PUMP APPARATUS

Abstract

A pump apparatus includes: a housing; a pump unit; a suction passage; a discharge passage member including a discharge hydraulic passage which is formed therein, and which is arranged to discharge the hydraulic fluid pressurized by the pump unit to an outside of the housing; a first discharge passage insertion hole which is formed in the pump unit, and into which the discharge passage member is inserted through an elastic member; a second discharge passage insertion hole which is formed in the housing, and into which the discharge passage member is inserted through an elastic member; and an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member within the first discharge passage insertion hole and the second discharge passage insertion hole.

Description

BACKGROUND OF THE INVENTION

This invention relates to a pump apparatus arranged to discharge a desired hydraulic pressure by a pump.

U.S. Patent Application Publication No. 2011/0062773 A1 (corresponding to Japanese Patent Application Publication No. 2011-64147) discloses a conventional pump apparatus in which a center plate is assembled to a housing, and a discharge portion received in a receiving hole formed in the housing is inserted into the center plate, so that a discharge passage confronts a low pressure chamber, so as to decrease a size of the pump unit.

SUMMARY OF THE INVENTION

However, in the above-described conventional apparatus, the assembly error and the dimension error of the housing and the center plate are generated. Accordingly, it is difficult to ensure the assembling characteristic (ease of assembly).

It is, therefore, an object of the present invention to provide a pump apparatus devised to solve the above-mentioned problem, and readily assemble the pump apparatus while suppressing error.

According to one aspect of the present invention, a pump apparatus comprises: a housing; a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber; a suction passage which is opened in an outer circumference of the pump unit, and which is arranged to supply a hydraulic fluid into the pump unit; a discharge passage member including a discharge hydraulic passage which is formed therein, and which is arranged to discharge the hydraulic fluid pressurized by the pump unit to an outside of the housing; a first discharge passage insertion hole which is formed in the pump unit, and into which the discharge passage member is inserted through an elastic member; a second discharge passage insertion hole which is formed in the housing, and into which the discharge passage member is inserted through an elastic member; and an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member within the first discharge passage insertion hole and the second discharge passage insertion hole.

According to another aspect of the invention, a pump apparatus comprises: a housing; a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber; a discharge passage which is arranged to discharge a hydraulic fluid pressurized by the pump unit, through the housing to an outside of the housing; a discharge passage member which constitutes the discharge passage, and which includes a discharge hydraulic passage formed therein; a first discharge passage insertion hole which is formed in the pump unit, and into which an one end portion of the discharge passage member is inserted through an elastic member; a second discharge passage insertion hole which is formed in the housing, and into which the other end portion of the discharge passage member is inserted through an elastic member; an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member with respect to the first discharge passage insertion hole and the second discharge passage insertion hole; and the first discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween, the second discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween, a radial position adjusting mechanism arranged to adjust a radial position relationship between the each of the first discharge passage insertion hole and the second discharge passage insertion hole, and the discharge passage member.

According to still another aspect of the invention, a pump apparatus comprises: a housing; a pump unit which is received in a receiving portion formed in the housing, and which includes a low pressure portion and a high pressure portion formed therein; a suction passage formed in the housing, and arranged to supply a hydraulic fluid to the low pressure portion of the pump unit; a low pressure chamber connected with the suction passage and the low pressure portion, and formed between the pump unit and a wall portion forming the receiving portion when the pump unit is received in the receiving portion; a discharge passage arranged to discharge the hydraulic fluid pressurized by the pump unit; a connection pipe which constitutes the discharge passage, and which passes through the low pressure chamber, and which connects the housing and the high pressure chamber, a first connection pipe insertion hole which is formed in the pump unit, and into which the connection pipe is inserted through an elastic member; a second connection pipe insertion hole which is formed in the housing, and into which the connection pipe is inserted through the elastic member; an axial position adjusting mechanism arranged to adjust an axial position of the connection pipe with respect to the first connection pipe insertion hole and the second connection pipe insertion hole; and the first connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween, the second connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween, a radial position adjusting mechanism arranged to adjust a radial position relationship between each of the first connection pipe insertion hole and the second connection pipe insertion hole, and the connection pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a hydraulic pressure circuit diagram showing a brake hydraulic pressure control apparatus to which a pump apparatus according to a first embodiment of the present invention is applicable.

FIGS. 2A-2C are skeleton diagrams showing a housing of a hydraulic pressure control unit in the brake hydraulic pressure control apparatus of FIG. 1.

FIGS. 3A-3C are skeleton diagrams showing the housing when viewed from directions different from FIGS. 2A-2C.

FIG. 4 is a perspective view showing the housing of FIGS. 2A-2C and FIG. 3A-3C.

FIG. 5 is a perspective view showing the housing of FIGS. 2A-2C and FIG. 3A-3C.

FIG. 6 is a perspective view showing the housing of FIGS. 2A-2C and FIG. 3A-3C.

FIG. 7 is a perspective view showing a pump unit and discharge portions in the pump apparatus according to the first embodiment of the present invention.

FIG. 8 is a sectional view showing a portion in a state where the pump unit and the discharge portions are received within the housing, in the pump apparatus according to the first embodiment of the present invention.

FIG. 9 is a sectional view taken along a section line A-A of FIG. 8.

FIG. 10 is an enlarged sectional view showing a portion near the discharge portion.

FIG. 11 is an enlarged sectional view showing a portion near a discharge portion in a pump apparatus according to a second embodiment of the present invention.

FIG. 12 is an enlarged sectional view showing a portion near a discharge portion in a pump apparatus according to a third embodiment of the present invention.

FIG. 13 is an enlarged sectional view showing a portion near a discharge portion in a pump apparatus according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Pump apparatuses according to embodiments of the present invention will be explained hereinafter with reference to the accompanying drawings.

First Embodiment

[Structure of Brake Hydraulic Pressure Circuit]

FIG. 1 is a hydraulic pressure circuit diagram showing a brake hydraulic pressure control apparatus 32. The hydraulic pressure circuit is formed within a hydraulic pressure control unit 30 provided between a master cylinder M/C and wheel cylinders W/C. FIG. 2 and FIG. 3 are skeleton diagrams of a housing 31 of a hydraulic pressure control unit 30. FIG. 2 and FIG. 3 show a state in which valves, the control unit, and a motor M are detached for facilitating the understanding.

This brake hydraulic pressure control apparatus 32 performs a hydraulic pressure control in accordance with a desired hydraulic pressure for a Vehicle Dynamics Control (hereinafter, referred to as a VDC), and an Anti-lock Brake System (hereinafter, referred to as ABS) from a controller. Brake hydraulic pressure control apparatus 32 has an x-piping system having two systems including a brake hydraulic pressure circuit 21P of a P system and a brake hydraulic pressure circuit 21S of an S system. The P system is connected with a wheel cylinder W/C(FL) of a left front wheel, and a wheel cylinder W/C(RR) of a right rear wheel. The S system is connected with a wheel cylinder W/C(FR) of a right front wheel, and a wheel cylinder W/C(RL) of a left rear wheel. Brake hydraulic pressure control apparatus 32 and wheel cylinders W/C are connected with wheel cylinder ports 19 (19RL, 19FR, 19FL, and 19RR) formed on an upper surface 31c of housing 31 described later. Moreover, a pump unit P is a tandem gear pump including a gear pump PP in the P system, and a gear pump PS in the S system.

Master cylinder M/C and hydraulic pressure control unit 30 are connected with each other by fluid passages 18P and 18S through master cylinder ports 20P and 20S formed on a port connection surface 31a1 of housing 31 described later. These fluid passages 18 (18P and 18S) and a suction side of pump unit P are connected by fluid passages 10P and 10S. Moreover, there is provided a master cylinder pressure sensor 22 provided on fluid passage 18P between master cylinder port 20P, and a connection portion between fluid passage 18P and fluid passage 10P.

A discharge side of pump unit P and wheel cylinders W/C are connected, respectively, by fluid passages 11P and 11S. There are provided pressure increasing valves 3FL, 3RR, 3FR, and 3RL which are normally-open solenoid valves corresponding to wheel cylinders W/C, and which are provided on fluid passages 11 (11P and 11S). Moreover, there are check valves 6 (6P and 6S) which are provided on fluid passages 11 (11P and 11S) between pressure increasing valves 3 (3FL and 3RR, and 3FR and 3RL) and pump unit P. Each of check valves 6 is arranged to allow a flow of a brake hydraulic pressure in a direction from pump unit P toward the corresponding pressure increasing valve 3, and to prohibit a flow of the brake hydraulic pressure in an opposite direction from the corresponding pressure increasing valve 3 to pump unit P. Moreover, there are provided discharge pressure sensors 23P and 23S disposed on fluid passages 11 (11P and 11S) between pressure increasing valves 3 (3FL and 3RR, and 3FR and 3RL) and pump unit P.

Moreover, there are provided fluid passages 16FL, 16RR, 16FR, and 16RL which are disposed on fluid passages 11 (11P and 11S), and which bypass the corresponding pressure increasing valves 3, respectively. There are provided check valves 9FL, 9RR, 9FR, and 9RL which are disposed, respectively, on fluid passages 16 (16FL, 16RR, 16FR, and 16RL). Each of check valves 9 (9FL, 9RR, 9FR, and 9RL) is arranged to allow a flow of the brake hydraulic pressure in a direction from the corresponding wheel cylinder W/C to pump unit P, and to prohibit a flow of the brake hydraulic pressure in an opposite direction from pump unit P to the corresponding wheel cylinder W/C.

Master cylinder M/C and fluid passages 11 (11P and 11S) are connected by fluid passages 12P and 12S. Fluid passages 11 and fluid passages 12 are joined between pump unit P and the corresponding pressure increasing valves 3. There are provided gate out valves 2P and 2S which are normally open solenoid valves, and which are disposed on fluid passages 12. Moreover, there are provided fluid passages 17P and 17S which are disposed on fluid passages 12, and which bypass the respective gate out valves 2 (2P and 2S). Furthermore, there are provided check valves 8P and 8S which are disposed on fluid passages 17 (17P and 17S). Each of check valves 8P and 8S is arranged to allow a flow of the brake hydraulic pressure in a direction from the master cylinder M/C's side toward the corresponding wheel cylinders W/C, and to prohibit a flow of the brake hydraulic pressure in an opposite direction from the corresponding wheel cylinders W/C toward the master cylinder M/C's side.

Furthermore, there are provided reservoir 15P and 15S which are disposed on the suction side of pump unit P. These reservoirs 15P and 15S and pump unit P are connected by fluid passages 14P and 14S. There are provided check valves 7P and 7S which are disposed between reservoirs 15 (15P and 15S) and pump unit P. Wheel cylinders W/C and fluid passages 14 (14P and 14S) are connected by fluid passages 13P and 13S. Fluid passages 13 (13P and 13S) and fluid passages 14 are joined between check valves 7 (7P and 7S), and reservoirs 15 (15P and 15S). There are provided pressure decreasing valves 4FL, 4RR, 4FR, and 4RL which are disposed on fluid passages 13 (13P and 13S), and which are normally-closed solenoid valves.

[Structure of Housing]

In below illustrations, a surface on which master cylinder ports 20 are opened is a front surface 31a, and a back surface of front surface 31a is a rear surface 31b. A surface on which wheel cylinder ports 19 are opened is an upper surface 31c. A back surface of upper surface 31c is a lower surface 31d. A side surface on a left side of front surface 31a is a left side surface 31e. A side surface on a right side of front surface 31a is a right side surface 31f. FIG. 2A is a view when housing 31 is viewed from front surface 31a's side. FIG. 2B is a view when housing 31 is viewed from the upper surface 31c's side. FIG. 2C is a view when housing 31 is viewed from the rear surface 31d's side. FIG. 3A is a view when housing 31 is viewed from the rear surface 31b's side. FIG. 3B is a view when housing 31 is viewed from the right side surface 31f's side. FIG. 3C is a view when housing 31 is viewed from the left side surface 31e's side.

Moreover, FIG. 4, FIG. 5, and FIG. 6 are perspective views showing housing 31. FIG. 4 is a view when housing 31 is viewed from the rear surface 31b's side, the upper surface 31c's side, and the left side surface 31e's side. FIG. 5 is a view when housing 31 is viewed from the front surface 31a's side, the upper surface 31c's side, and the left side surface 31e's side. FIG. 6 is a view when a unit case 34 and motor M are attached.

Housing 31 has a substantially rectangular parallelepiped (rectangular solid) shape. Motor M is mounted on the front surface 31a's side. The solenoid valves of gate out valves 2, pressure increasing valves 3, and pressure decreasing valves 4, and an electric unit arranged to drive the solenoid valves are mounted on the rear surface 31b's side. The electric unit includes a circuit board arranged to perform a predetermined calculation in accordance with input signals of wheel speed sensors and so on which are attached to the vehicle. The electric unit is arranged to output a predetermined electric signal to solenoids attached to the solenoid valves, and motor M. This electric unit is received within unit case 34. Housing 31 includes power supply holes which penetrate through front surface 31a and rear surface 31b. Electrodes of motor M are inserted into these power supply holes 24, so that the electric unit and motor M are connected.

Housing 31 includes a valve mounting holes in which the solenoid valves are mounted by press fit or staking; a plurality of fluid passages which connect the ports and the solenoid valves; and holes in which ports (wheel cylinder ports 19 and master cylinder ports 20) connected with the cylinders (wheel cylinders W/C and master cylinders M/C), and reservoirs 15 are disposed. These holes, fluid passages, and so on are formed by drilling the respective surfaces from the outside of housing 31.

Housing 31 includes a port connection surface 31a1 which is formed on front surface 31a on the upper surface 31c's side, which has a surface normal on the motor M's side, and which is substantially parallel with front surface 31a. Port connection surface 31a1 is formed to protrude in a forward direction (the motor side in the axial direction of the motor drive shaft) from front surface 31a. Master cylinder ports 20 are formed on this port connection surface 31a1.

Pump unit P is received within a substantially cylindrical receiving portion 41 which penetrates through housing 31 from front surface 31a to rear surface 31b. This receiving portion 41 includes an opening portion which is on the rear surface 31b's side, and which is closed by a pump cover 35. Moreover, housing 31 includes a discharge portion receiving hole 47 (47P and 47S) which extends from left side surface 31e of housing 31 to right side surface 31f of housing 31, and which is substantially perpendicular to receiving portion 41. Discharge portions 48 (48P and 48S) are received within this discharge portion receiving hole 47. Discharge portions 48 are connected with the discharge side of pump P.

[Structure of Pump Unit]

FIG. 7 is a perspective view showing pump unit P and discharge portions 48. Moreover, FIG. 8 is a partially sectional view showing a state where pump unit P and discharge portions 48 are received within housing 31. FIG. 9 is a sectional view taken along a section line A-A of FIG. 8.

Pump unit P includes a pump housing 36, a center plate 49, and a pump cover 35. Pump housing 36, center plate 49, and pump cover 35 have, respectively, substantially cylindrical outer profiles. Pump housing 36, center plate 49, and pump cover 35 are arranged in this order in the axial direction. Pump housing 36 includes a bottomed hollow section. Gear pump PP is received in a space between this hollow section of pump housing 36 and center plate 49. Moreover, pump cover 35 includes a bottomed hollow section. Gear pump PS is received in a space between this hollow section of pump cover 35 and center plate 49.

Pump housing 36 includes an O-ring groove 55a and an O-ring groove 55b formed on an outer circumference of pump housing 36. Pump cover 35 includes an O-ring groove 55c formed on an outer circumference of pump cover 35. O-ring grooves 55a, 55b, and 55c are formed to be apart from each other in the axial direction. O-rings 45a, 45b, and 45c are mounted, respectively, in O-ring grooves 55a, 55b, and 55c.

Pump housing 36 includes a circumferential side surface 56P formed between O-ring 45a and O-ring 45b. Moreover, there is formed a low pressure chamber groove 57P which is formed on an inner circumference of receiving portion 41 at a position to confront circumferential side surface 56P when pump unit P is received within receiving portion 41 of housing 31. There is formed a low pressure chamber 40P defined by circumferential side surface 56P of pump housing 36, low pressure chamber groove 57P of receiving portion 41, O-ring 45a, and O-ring 45b.

Center plate 49 includes a low pressure chamber groove 56S formed on an outer circumference of center plate 49 in a circumferential direction. Moreover, housing 31 includes a low pressure chamber groove 57S which is formed on an inner circumference of receiving portion 41 at a position to confront low pressure chamber groove 56S when pump unit P is received within receiving portion 41 of housing 31.

Gear pumps PP and PS include, respectively, first gear plates 38P and 38S, second gear plates 39P and 39S, and a pair of driving and driven gears 46P and 46S which are externally engaged with each other. There are formed suction portions 58P and 58S between first gear plates 38P and 38S, and second gear plates 39P and 39S. An O-ring 37P is provided on an outer circumference of gear pump PP on the opening portion side of suction portion 58P of gear pump PP, that is, on an outer circumference of gear pump PP on a side on which gear pump PP and pump housing 36 are abutted on each other. Moreover, an O-ring 37S is provided on an outer circumference of gear pump PS on the opening portion side of suction portion 58S of gear pump PS, that is, on an outer circumference of gear pump PS on a side on which gear pump PS and center plate 49 are abutted on each other.

A shaft 63 is connected to a drive side of gear 46P and a drive side of gear 46S. This shaft 63 penetrates through first gear plates 38P and 38S, second gear plates 39P and 39S, center plate 49, and pump housing 36. This shaft 63 is connected to a rotational shaft of motor M.

There is formed a high pressure chamber 480P defined by pump housing 36, center plate 49, first gear plate 38P, and second gear plate 39P. Moreover, there is formed a high pressure chamber 480S defined by pump cover 35, center plate 49, first gear plate 38S, and second gear plate 39S.

Pump housing 36 includes a suction passage 42P connecting suction portion 58P of gear pump PP and low pressure chamber 40P. Moreover, center plate 49 includes a suction passage 42S connecting suction portion 58S of gear pump PS and low pressure chamber 40S.

Discharge portions 48P and 48S are received, respectively, within discharge portion receiving holes 47P and 47S formed to extend from left side surface 31e of housing 31 to right side surface 31f of housing 31 to be substantially perpendicular to receiving portion 41, as described above. That is, these discharge portions 48P and 48S are received within discharge portion receiving holes 47P and 47S formed in symmetry with respect to a line in a radial direction of low pressure chambers 40P and 40S.

Discharge passages 43P and 43S are formed by discharge passage members 481P and 481S each having an axial through hole. One end portions of discharge passage members 481P and 481S are inserted, respectively, together with O-rings 483P and 483S into insertion holes 64P and 64S formed in side surfaces of center plate 49. In this case, discharge passage members 481P and 481S penetrate through low pressure chamber 40S. Center plate 49 includes connection passages 49P and 49S which connect opening portions of one ends of discharge passage members 481P and 481S, and high pressure chambers 480P and 480S, respectively.

FIG. 10 is an enlarged sectional view showing a portion near the discharge portion in the pump apparatus according to the first embodiment of the present invention. In FIG. 10, an axis X1 is defined by a direction in which discharge portion 48 extends. Discharge portion 48P has a structure substantially identical to that of discharge portion 48S. Accordingly, the only discharge portion 48S is illustrated below. Discharge portion 48S includes discharge passage member 481S inserted into center plate 49; a closing member 482S serving as a cover closing discharge portion receiving hole 47S; and a wave washer 70 elastically sandwiched between discharge passage member 481S and closing member 482S.

Discharge passage member 481S includes a tip end portion 481a which is formed into a tapered shape, and which is inserted into insertion hole 64S of center plate 49, and a body portion 481h which is formed into a cylindrical shape, and which has a diameter larger than that of tapered portion 481a.

Tip end portion 481a of discharge passage member 481S includes a seal groove 481b formed on an outer circumference of tip end portion 481a. An O-ring 483S is mounted in this seal groove 481b. When tip end portion 481a is inserted within insertion hole 64S, O-ring 483S liquid-tightly separates connection passage 49S and low pressure chamber 40S within insertion hole 64S. Tip end portion 481a includes a tip end side discharge passage 481c which is formed at a shaft center of tip end portion 481a, and which penetrates through tip end portion 481a.

Body portion 481h is a member which is inserted into a discharge passage member receiving hole 47c of discharge portion receiving hole 47S that receives discharge passage member 481S. Body portion 481h includes a seal groove 481e formed on an outer circumference of body portion 481h. An O-ring 484S is mounted in this seal groove 481e. Body portion 481h includes a body side discharge passage 481f which is formed at a shaft center of body portion 481h in the axial direction, and which is connected with tip end side discharge passage 481c. Discharge passage member 481S includes a stepped portion 481d provided at a connection portion between tip end portion 481a and body portion 481h. This stepped portion 481d is engaged with low pressure chamber groove 56S of center plate 49 so as to position discharge passage member 481S in a direction of axis X1. Accordingly, low pressure chamber groove 56S serves as an engagement portion which is engaged with stepped portion 481d.

As shown in a partially enlarged view of body portion 481h, there is formed a radial gap provided radially between the outer circumference of body portion 481h and discharge passage member receiving hole 47c. This gap is arranged to ensure sufficient liquid-tightness by the elastic deformation of O-ring 484S, and to absorb the deviation even when a radial position relationship between discharge passage member 481S and discharge passage member receiving hole 47c is misaligned (deviated) due to the manufacturing error, assembly error, and so on. That is, in discharge passage member 481S, tip end portion 481a is inserted into center plate 49, and body portion 481h is inserted into discharge passage member receiving hole 47c formed in housing 31. In this case, the position relationship between center plate 49 and housing 31 in the direction of the motor rotational shaft is not stable due to the assembly error and so on. For improving the assembling accuracy so as to dissolve the above-described matter, it is necessary to improve the accuracy of the entire components. Accordingly, the cost may be increased. On the other hand, in the pump apparatus according to this embodiment, there is provided the radial gap. With this, it is possible to absorb the deviation in the radial direction. Therefore, since the high accuracy of the components is not needed, it is possible to ensure the facility (ease) of the assembling operation while avoiding the cost increase. Besides, O-ring 484S liquid-tightly separates low pressure chamber 40S and body portion side discharge passage 481f.

Body portion side discharge passage 481f is opened on a body portion side end surface 481g of discharge passage member 481S. A position of this body portion side end surface 481g in the direction of axis X1 is designed to be positioned at a position on the outer side of the housing outer side end portion of discharge passage member receiving hole 47c. Wave washer 70 is provided on this body portion side end surface 481g. Closing member 482S is assembled through wave washer 70.

Closing member 482S includes a cover portion 482a received within a cover portion receiving hole 47a of discharge portion receiving hole 47S, and a cylindrical portion 482b received within a cylindrical portion receiving hole 47b of discharge portion receiving hole 47S. Cylindrical portion receiving hole 47b has a diameter larger than that of discharge passage member receiving hole 47c. A radial portion of cylindrical portion receiving hole 47b of closing member receiving hole 47S is connected to the discharge hydraulic passage. Moreover, cover member receiving hole 47a has a diameter larger than that of cylindrical portion receiving hole 47b. Discharge portion receiving hole 47S is liquid-tightly closed by the staking and so on after closing member 482S is inserted. Cylindrical portion 482b includes a damper chamber 482c which is formed at a shaft center of cylindrical portion 482b, which has a diameter larger than that of body portion side discharge passage 481f, and which has an axial length longer than that of body portion side discharge passage 481f. Moreover, cylindrical portion 482b includes a radial hydraulic passage 482d which is formed radially outside this damper chamber 482c. Cylindrical portion 482b includes a discharge groove 482h formed on an outer circumference of cylindrical portion 482b at an axial position at which discharge groove 482h is overlapped with radial hydraulic passage 482d; and a ring groove 482e and a ring groove 482f formed on both sides of this discharge groove 482h in the axial direction. Ring groove 482f receives an O-ring 485S. Ring groove 482e receives an O-ring 486S. Moreover, wave washer 70 is abutted on a io pump side end surface 482g of cylindrical portion 482b.

Next, an assembling process, and functions of the members are illustrated. When hydraulic pressure control unit 30 is assembled, pump unit P is assembled to housing 31. With this, the position of center plate 49 with respect to housing 31 is determined. Then, discharge passage member 481S is inserted from discharge portion receiving hole 47S formed in the side surface of housing 31. The tip end of discharge passage member 481S is inserted within insertion hole 64S of center plate 49. In this case, even when the position relationship between discharge passage member receiving hole 47c and center plate 49 is deviated (misaligned) in a measure, it is possible to insert discharge passage member 481S since there is the radial gap between discharge passage member 481S and discharge passage member receiving hole 47c. The position of discharge passage member 481S in the direction of the axis X1 is determined by the engagement between low pressure chamber groove 56S of center plate 49, and stepped portion 481d of discharge passage member 481S.

Next, wave washer 70 is inserted. Moreover, closing member 482S is inserted into discharge portion receiving hole 47S. In this case, pump side end surface 482g of closing member 482S presses discharge passage member 481S through wave washer 70 in the direction of the axis X1 (in the rightward direction of FIG. 10). Besides, body portion side end surface 481g of discharge passage member 481S is exposed within cylindrical portion receiving hole 47b having the large diameter. Accordingly, it is possible to constantly act the elastic pressing force by wave washer 70. On the other hand, closing member 482S is positioned by the staking and so on of cover portion 482a. Accordingly, there are problems such as the manufacturing accuracy of cover portion receiving hole 47a and closing member 482S, and the assembly error in the direction of the axis X1. In this case, it is possible to absorb the error in the direction of the axis X1 by providing the elastic force by wave washer 70.

That is, discharge passage member 481S and closing member 482S are different members. Discharge passage member 481S absorbs the radial error. On the other hand, wave washer 70 absorbs the error in the direction of the axis X1. With this, it is possible to ensure the stable assembling accuracy.

(1) The pump apparatus according to the first embodiment of the present invention includes a housing 31, a pump unit P received within a receiving portion 41 which is formed in housing 31, and which constitutes low pressure chamber 40S; suction passages 58S and 58P opened in an outer circumference of pump unit P, and arranged to supply a hydraulic fluid to pump unit P; a discharge passage member 481S including a tip end side discharge passage 481c and a body portion side discharge passage 481f (discharge passage) formed within discharge passage member 481S so as to discharge the hydraulic fluid pressurized by pump unit P to the outside of pump housing 31; insertion hole 64S (first discharge passage insertion hole) which is formed in pump unit P, and in which discharge passage member 481S is inserted through O-ring 483S (elastic member); discharge passage member receiving hole 47c (second discharge passage insertion hole) which is formed in housing 31, and in which discharge passage member 481S is inserted through O-ring 484S (elastic member); and a wave washer 70 (axial position adjusting mechanism) arranged to position discharge passage member 481S within discharge passage member receiving hole 47c in the axial direction.

Accordingly, it is possible to absorb the assembly error of discharge passage member 481S and so on, and thereby to ensure the facility (ease) of the assembling operation without needs for the extreme increase of the manufacturing accuracy of the components.

(2) In the pump apparatus according to the embodiments of the present invention, wave washer 70 is an elastic member which is arranged to apply the elastic force to discharge passage member 481S.

Accordingly, it is possible to absorb the error in the wide range by elastically absorbing the manufacturing error of the components, the assembly error, and so on, and to ensure the stable assembling characteristic.

(3) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a predetermined radial gap between discharge passage member 481S and each of insertion hole 64S and discharge passage member receiving hole 47c (each of the insertion holes), and a radial position adjusting mechanism arranged to adjust the position relationship between the insertion holes and the discharge passage member 481S.

Accordingly, it is also possible to elastically adjust the assembly error in the radial direction, and so on, and to ensure the stable assembling characteristic.

(4) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes closing member 482S which is fixed to housing 31, and which closes discharge passage member receiving hole 47c (second discharge passage insertion hole); and wave washer 70 (the axial position adjusting mechanism) is provided between discharge passage member 481S and closing member 482S.

Accordingly, it is possible to ensure the stable assembling operation by the elastic force even when there is the variation of the axial lengths of the closing member 482S and discharge passage member 481S.

(5) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is wave washer 70 (plate spring) disposed in a contracted state between discharge passage member 481S and closing member 482S. Accordingly, it is possible to apply the large elastic force even when there is only slight gap relative to the gap necessary for the elastic member such as the coil spring and so on.
(6) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a low pressure chamber groove 56S (engagement portion) which is formed in insertion hole 64S, and which is arranged to be engaged with discharge passage member 481S. The axial position adjusting mechanism is an elastic member arranged to urge discharge passage member 481S toward low pressure chamber groove 56S. Accordingly, it is possible to engage low pressure chamber groove 56S and stepped portion 481d, and to further improve the seal characteristic between connection passage 49S having the high pressure and low pressure chamber 40S.

Second Embodiment

Next, a pump apparatus according to a second embodiment of the present invention is illustrated below. The pump apparatus according to the second embodiment of the present invention has a basic structure substantially identical to the pump apparatus according to the first embodiment of the present invention. Accordingly, only different portions are illustrated. FIG. 11 is an enlarged sectional view showing a portion near the discharge portion in the pump apparatus according to the second embodiment of the present invention. In the pump apparatus according to the first embodiment, wave washer 70 which is the elastic member is provided between discharge passage member 481S and closing member 482S. On the other hand, in the pump apparatus according to the second embodiment wave washer 70 is provided between discharge passage member 481S and insertion hole 64S, unlike the pump apparatus according to the first embodiment. Besides, in the pump apparatus according to the first embodiment, the positioning is performed by the engagement between stepped portion 481d of discharge passage member 481S and low pressure chamber groove 56S. On the other hand, in the pump apparatus according to the second embodiment, stepped portion 481d and low pressure chamber groove 56S are elastically held with a gap, by the change of the position of wave washer 70. The basic effects and functions in the pump apparatus according to the second embodiment are substantially identical to those in the pump apparatus according to the first embodiment. Accordingly, the repetitive illustrations are omitted.

Third Embodiment

Next, a pump apparatus according to a third embodiment of the present invention is illustrated. The pump apparatus according to the third embodiment has a basic structure substantially identical to that of the pump apparatus according to the first embodiment. Accordingly, only different portions are illustrated. FIG. 12 is an enlarged sectional view showing a portion near the discharge portion in the pump apparatus according to the third embodiment. In the pump apparatus according to the first embodiment, pump side end surface 482g of closing member 482S applies the elastic force to the discharge passage member 481S through wave washer 70. On the other hand, in the pump apparatus according to the third embodiment, a coil spring 71 is provided in place of wave washer 70. Moreover, closing member 482S has an axial length shorter than that of closing member 482S in the pump apparatus according to the first embodiment. With this, it is possible to form a large damper chamber by increasing a space formed by the wall surface of cylindrical receiving hole 47b, pump side end surface 482g, and body portion side end surface 481g. With this, it is possible to ensure the damping characteristic of the discharge passage. Besides, the radial position adjusting function, and the position adjusting function in the direction of the axis X1 are identical to those of the pump apparatus according to the first embodiment. Accordingly, the repetitive illustrations are omitted.

(7) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a damper chamber formed by closing member 482S, discharge passage member 481S, and cylindrical portion receiving hole 47b (second passage member insertion hole). Accordingly, it is possible to effectively suppress the pulsation of the discharge pressure. Moreover, it is possible to ensure the volume necessary for the damping by using coil spring 71, and thereby to improve the damping characteristic.
(8) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is coil spring 71 disposed in a contracted state between discharge passage member 481S and closing member 482S. Accordingly, it is possible to ensure the larger elastic deformation region with respect to axis X1, relative to the wave washer and so on. Consequently, it is possible to effectively absorb the assembly error and so on. Moreover, it is possible to obtain the damping space, and thereby to ensure the damping characteristic.

Fourth Embodiment

Next, a pump apparatus according to a fourth embodiment of the present invention is illustrated. The pump apparatus according to the fourth embodiment has a basic structure substantially identical to the pump apparatus according to the first embodiment. Accordingly, only different portions are illustrated. FIG. 13 is an enlarged sectional view showing portions near the discharge portion of the pump apparatus according to the fourth embodiment of the present invention. In the pump apparatus according to the first embodiment, pump side end surface 482g of closing member 482S applies the elastic force to discharge passage member 481S through wave washer 70. On the other hand, the pump apparatus according to the fourth embodiment includes a plunger member 72, in place of wave washer 70. An inner wall of damper chamber 482c and plunger 72 are fixed by the press fit.

Plunger member 72 is a bottomed cylindrical member. Plunger member 72 includes a cylindrical portion 72b which is formed into a hollow cylindrical shape; a bottom portion 72a which closes an opening of body portion side discharge passage 481f of the discharge passage member 481S; an axial orifice 72c formed in bottom portion 72a, and opened to body portion side discharge passage 481f; and radial orifices 72d formed in cylindrical portion 72b, and opened to the discharge passage within housing 31.

At the assembly operation, first, discharge passage member 481S is inserted within discharge portion receiving hole 47S. Next, plunger member 72 is slightly mounted in the inner wall of damper chamber 482c of closing member 482S. In this temporary assembly state, this is inserted into discharge portion receiving hole 47S. Then, when cover portion 482a of closing member 482S is pressed into discharge portion receiving hole 47S by being applied with the load, the relative position between plunger member 72 and closing member 482S is varied. The press fit is continued until cover portion 482a of closing member 4825 is fully received within cover portion receiving hole 47a. With this, the urging force toward the pump unit side is applied to discharge passage member 481S.

(9) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism includes plunger member 72 which is arranged to be moved relative to closing member 482S (or discharge passage member 481S) in the axial direction. The axial position adjusting mechanism is arranged to adjust the relative position between plunger member 72 and closing member 482S (or discharge passage member 481S). With this, it is possible to absorb the assembly error in the axial direction, and to ensure the facility (ease) of the assembling operation without needs for the extreme increase of the manufacturing accuracy of the components. Besides, in the pump apparatus according to the fourth embodiment of the present invention, the axial position is adjusted by the relative displacement between closing member 482S and plunger member 72. However, discharge passage member 481S and plunger member 72 may be relatively moved, and the press fit may be performed by the pressing force of closing member 482S.

As described above, the pump apparatuses according to the embodiments of the present invention are illustrated. However, the present invention is not limited to the above-described embodiments. The other structures may be employed within the gist of the invention. For example, in the pump apparatus according to the embodiments of the present invention, the O-ring is used as the elastic member. However, the elastic member is not limited to the O-ring. It is optional to elastically absorb the deviation of the radial position by other elastic members. Moreover, in the pump apparatus according to the embodiments of the present invention, the elastic member and the press fit which serve as the axial position adjusting mechanism absorb the assembly error and so on. However, it is optional to employ a structure in which the axial position is adjusted by screw and so on.

[1] A pump apparatus according to the embodiments of the present invention including: a housing; a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber; a suction passage which is opened in an outer circumference of the pump unit, and which is arranged to supply a hydraulic fluid into the pump unit; a discharge passage member including a discharge hydraulic passage which is formed therein, and which is arranged to discharge the hydraulic fluid pressurized by the pump unit to an outside of the housing; a first discharge passage insertion hole which is formed in the pump unit, and into which the discharge passage member is inserted through an elastic member; a second discharge passage insertion hole which is formed in the housing, and into which the discharge passage member is inserted through an elastic member; and an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member within the first discharge passage insertion hole and the second discharge passage insertion hole.

With this, it is possible to absorb the assembly errors of the discharge passage member and so on, and to ensure the facility (ease) of the assembly operation without needs for the extreme increase of the manufacturing accuracy of the components.

[2] In the pump apparatuses according to the embodiments of the present invention, the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the discharge passage member.

Accordingly, it is possible to absorb the error in the wide range by elastically absorbing the manufacturing error of the components, the assembly error of the components and so on, and to ensure the stable assembly characteristic.

[3] In the pump apparatus according to the embodiments of the present invention, the first discharge passage insertion hole and the discharge passage member are disposed with a gap therebetween; the second discharge passage insertion hole and the discharge passage member are disposed with a gap therebetween; and the pump apparatus further includes a radial position adjusting mechanism arranged to adjust a position relationship between each of the first discharge passage insertion hole and the second discharge passage insertion hole, and the discharge passage member.

Accordingly, it is possible to elastically adjust the assembly error and so on in the radial direction, and to ensure the stable assembly characteristic.

[4] In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a closing member which is fixed to the housing, and which closes the second discharge passage insertion hole; and the axial position adjusting mechanism is disposed between the discharge passage member and the closing member.

Accordingly, it is possible to ensure the stable assembly characteristic by the elastic force even when there are the variations of the axial lengths of the closing member and the discharge passage member.

[5] In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a damper chamber formed by the closing member, the discharge passage member, and a wall surface of the second passage member insertion hole.

Accordingly, it is possible to effectively suppress the pulsation of the discharge pressure.

[6] In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism includes a plunger member arranged to be moved in an axial direction relative to one of the discharge passage member and the closing member; and the axial position adjusting mechanism is arranged to adjust a relative position between the plunger member, and the one of the discharge passage member and the closing member.

Accordingly, it is possible to absorb the assembly error in the axial direction, and so on, and to ensure the facility (ease) of the assembly operation without needs for the extreme increase of the manufacturing accuracy of the components.

[7] In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is a plate spring disposed in a contracted state between the discharge passage member and the closing member.

Accordingly, it is possible to apply large elastic force by a short travel, and to decrease the size of the apparatus.

[8] In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is a coil spring disposed in a contracted state between the discharge passage member and the closing member.

Accordingly, it is possible to ensure the space which has a damping function of the discharge pressure, and to improve the damping characteristic.

[9] In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes an engagement portion which is formed in the first discharge passage insertion hole, and with which the discharge passage member is engaged; and the axial position adjusting mechanism is an elastic member arranged to urge the discharge passage member toward the engagement portion.

Accordingly, it is possible to position the discharge passage member with respect to the pump unit, and to ensure the facility of the assembly operation.

(10) The pump apparatus according to the embodiments of the present invention including: a housing; a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber; a discharge passage which is arranged to discharge a hydraulic fluid pressurized by the pump unit, through the housing to an outside of the housing; a discharge passage member which constitutes the discharge passage, and which includes a discharge hydraulic passage formed therein; a first discharge passage insertion hole which is formed in the pump unit, and into which an one end portion of the discharge passage member is inserted through an elastic member; a second discharge passage insertion hole which is formed in the housing, and into which the other end portion of the discharge passage member is inserted through an elastic member; an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member with respect to the first discharge passage insertion hole and the second discharge passage insertion hole; and the first discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween, the second discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween, a radial position adjusting mechanism arranged to adjust a radial position relationship between the each of the first discharge passage insertion hole and the second discharge passage insertion hole, and the discharge passage member.

Accordingly, it is possible to absorb the assembly error and so on of the discharge passage member in the axial direction and in the radial direction, and to ensure the facility (ease) of the assembly operation without needs for the extreme increase of the manufacturing accuracy of the components.

(11) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the discharge passage member.

Accordingly, it is possible to absorb the error in the wide range since the axial position adjusting mechanism absorbs the manufacturing errors of the components, and the assembly errors, and so on, and thereby to ensure the stable assembling characteristic.

(12) In the pump apparatus according to the embodiments of the present invention, the radial position adjusting mechanism is an O-ring mounted on an outer circumference of the discharge passage member; and the radial position adjusting mechanism is arranged to adjust a size of the radial gap by an elastic deformation of the O-ring.

Accordingly, it is possible to absorb the error of the radial position while ensuring the seal characteristic, by simple structure.

(13) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a closing member which is fixed to the housing, and which closes the second discharge passage insertion hole; and the axial position adjusting mechanism is disposed between the discharge passage member and the closing member.

Accordingly, it is possible to ensure the stable assembling characteristic even when the axial length of the closing member and the axial length of the discharge passage member are varied.

(14) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is a plate spring disposed in a contracted state between the discharge passage member and the closing member.

Accordingly, it is possible to attain the large elastic force by a short travel, and thereby to decrease the size of the pump apparatus.

(15) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a damper chamber formed by the closing member, the discharge passage member, and a wall surface of the second passage member insertion hole.

Accordingly, it is possible to effectively suppress the pulsation of the discharge pressure.

(16) A pump apparatus according to the embodiments of the present invention includes: a housing; a pump unit which is received in a receiving portion formed in the housing, and which includes a low pressure portion and a high pressure portion formed therein; a suction passage formed in the housing, and arranged to supply a hydraulic fluid to the low pressure portion of the pump unit; a low pressure chamber connected with the suction passage and the low pressure portion, and formed between the pump unit and a wall portion forming the receiving portion when the pump unit is received in the receiving portion; a discharge passage arranged to discharge the hydraulic fluid pressurized by the pump unit; a connection pipe which constitutes the discharge passage, and which passes through the low pressure chamber, and which connects the housing and the high pressure chamber, a first connection pipe insertion hole which is formed in the pump unit, and into which the connection pipe is inserted through an elastic member; a second connection pipe insertion hole which is formed in the housing, and into which the connection pipe is inserted through the elastic member; an axial position adjusting mechanism arranged to adjust an axial position of the connection pipe with respect to the first connection pipe insertion hole and the second connection pipe insertion hole; and the first connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween, the second connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween, a radial position adjusting mechanism arranged to adjust a radial position relationship between each of the first connection pipe insertion hole and the second connection pipe insertion hole, and the connection pipe.

(17) In the pump apparatus according to the embodiments of the present invention, the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the connection pipe.

Accordingly, it is possible to absorb the error in the wide range since the manufacturing error of the components, the assembly error, and so on are elastically absorbed, and thereby to ensure the stable assembling characteristic.

(18) In the pump apparatus according to the embodiments of the present invention, the radial position adjusting mechanism is an O-ring which is mounted on an outer circumference of the discharge passage member; and the radial position adjusting mechanism is arranged to adjust a size of the radial gap by an elastic deformation of the O-ring.

Accordingly, it is possible to absorb the error of the radial position while ensuring the seal characteristic, by the simple structure.

(19) In the pump apparatus according to the embodiments of the present invention, the pump apparatus further includes a closing member which is fixed to the housing, and which closes the second connection pipe insertion hole; the axial position adjusting mechanism is disposed between the connection pipe and the closing member; and the pump apparatus further includes a damper chamber formed by the closing member, the connection pipe, and a wall surface of the second connection pipe insertion hole.

Accordingly, it is possible to ensure the space having the damping function, and to improve the damping characteristic.

The entire contents of Japanese Patent Application No. 2012-154866 filed Jul. 10, 2012 are incorporated herein by reference.

Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art in light of the above teachings. The scope of the invention is defined with reference to the following claims.

Claims

1. A pump apparatus comprising:

a housing;

a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber;

a suction passage which is opened in an outer circumference of the pump unit, and which is arranged to supply a hydraulic fluid into the pump unit;

a discharge passage member including a discharge hydraulic passage which is formed therein, and which is arranged to discharge the hydraulic fluid pressurized by the pump unit to an outside of the housing;

a first discharge passage insertion hole which is formed in the pump unit, and into which the discharge passage member is inserted through an elastic member;

a second discharge passage insertion hole which is formed in the housing, and into which the discharge passage member is inserted through an elastic member; and

an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member within the first discharge passage insertion hole and the second discharge passage insertion hole.

2. The pump apparatus as claimed in claim 1, wherein the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the discharge passage member.

3. The pump apparatus as claimed in claim 2, wherein the first discharge passage insertion hole and the discharge passage member are disposed with a gap therebetween; the second discharge passage insertion hole and the discharge passage member are disposed with a gap therebetween; and the pump apparatus further comprises a radial position adjusting mechanism arranged to adjust a position relationship between each of the first discharge passage insertion hole and the second discharge passage insertion hole, and the discharge passage member.

4. The pump apparatus as claimed in claim 1, wherein the pump apparatus further comprises a closing member which is fixed to the housing, and which closes the second discharge passage insertion hole; and the axial position adjusting mechanism is disposed between the discharge passage member and the closing member.

5. The pump apparatus as claimed in claim 4, wherein the pump apparatus further comprises a damper chamber formed by the closing member, the discharge passage member, and a wall surface of the second passage member insertion hole.

6. The pump apparatus as claimed in claim 4, wherein the axial position adjusting mechanism includes a plunger member arranged to be moved in an axial direction relative to one of the discharge passage member and the closing member; and the axial position adjusting mechanism is arranged to adjust a relative position between the plunger member, and the one of the discharge passage member and the closing member.

7. The pump apparatus as claimed in claim 4, wherein the axial position adjusting mechanism is a plate spring disposed in a contracted state between the discharge passage member and the closing member.

8. The pump apparatus as claimed in claim 4, wherein the axial position adjusting mechanism is a coil spring disposed in a contracted state between the discharge passage member and the closing member.

9. The pump apparatus as claimed in claim 1, wherein the pump apparatus further comprises an engagement portion which is formed in the first discharge passage insertion hole, and with which the discharge passage member is engaged; and the axial position adjusting mechanism is an elastic member arranged to urge the discharge passage member toward the engagement portion.

10. A pump apparatus comprising:

a housing;

a pump unit received within a receiving portion which is formed in the housing, and which constitutes a low pressure chamber;

a discharge passage which is arranged to discharge a hydraulic fluid pressurized by the pump unit, through the housing to an outside of the housing;

a discharge passage member which constitutes the discharge passage, and which includes a discharge hydraulic passage formed therein;

a first discharge passage insertion hole which is formed in the pump unit, and into which an one end portion of the discharge passage member is inserted through an elastic member;

a second discharge passage insertion hole which is formed in the housing, and into which the other end portion of the discharge passage member is inserted through an elastic member;

an axial position adjusting mechanism arranged to adjust an axial position of the discharge passage member with respect to the first discharge passage insertion hole and the second discharge passage insertion hole; and

the first discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween,

the second discharge passage insertion hole and the discharge passage member being disposed with a predetermined radial gap therebetween,

a radial position adjusting mechanism arranged to adjust a radial position relationship between the each of the first discharge passage insertion hole and the second discharge passage insertion hole, and the discharge passage member.

11. The pump apparatus as claimed in claim 10, wherein the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the discharge passage member.

12. The pump apparatus as claimed in claim 11, wherein the radial position adjusting mechanism is an O-ring mounted on an outer circumference of the discharge passage member; and the radial position adjusting mechanism is arranged to adjust a size of the radial gap by an elastic deformation of the O-ring.

13. The pump apparatus as claimed in claim 12, wherein the pump apparatus further comprises a closing member which is fixed to the housing, and which closes the second discharge passage insertion hole; and the axial position adjusting mechanism is disposed between the discharge passage member and the closing member.

14. The pump apparatus as claimed in claim 13, wherein the axial position adjusting mechanism is a plate spring disposed in a contracted state between the discharge passage member and the closing member.

15. The pump apparatus as claimed in claim 13, wherein the pump apparatus further comprises a damper chamber formed by the closing member, the discharge passage member, and a wall surface of the second passage member insertion hole.

16. A pump apparatus comprising:

a housing;

a pump unit which is received in a receiving portion formed in the housing, and which includes a low pressure portion and a high pressure portion formed therein;

a suction passage formed in the housing, and arranged to supply a hydraulic fluid to the low pressure portion of the pump unit;

a low pressure chamber connected with the suction passage and the low pressure portion, and formed between the pump unit and a wall portion forming the receiving portion when the pump unit is received in the receiving portion; a discharge passage arranged to discharge the hydraulic fluid pressurized by the pump unit;

a connection pipe which constitutes the discharge passage, and which passes through the low pressure chamber, and which connects the housing and the high pressure chamber,

a first connection pipe insertion hole which is formed in the pump unit, and into which the connection pipe is inserted through an elastic member;

a second connection pipe insertion hole which is formed in the housing, and into which the connection pipe is inserted through the elastic member;

an axial position adjusting mechanism arranged to adjust an axial position of the connection pipe with respect to the first connection pipe insertion hole and the second connection pipe insertion hole; and

the first connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween,

the second connection pipe insertion hole and the connection pipe being disposed with a predetermined radial gap therebetween,

a radial position adjusting mechanism arranged to adjust a radial position relationship between each of the first connection pipe insertion hole and the second connection pipe insertion hole, and the connection pipe.

17. The pump apparatus as claimed in claim 16, wherein the axial position adjusting mechanism is an elastic member arranged to apply an elastic force to the connection pipe.

18. The pump apparatus as claimed in claim 16, wherein the radial position adjusting mechanism is an O-ring which is mounted on an outer circumference of the discharge passage member; and the radial position adjusting mechanism is arranged to adjust a size of the radial gap by an elastic deformation of the O-ring.

19. The pump apparatus as claimed in claim 16, wherein the pump apparatus further comprises a closing member which is fixed to the housing, and which closes the second connection pipe insertion hole; the axial position adjusting mechanism is disposed between the connection pipe and the closing member; and the pump apparatus further comprises a damper chamber formed by the closing member, the connection pipe, and a wall surface of the second connection pipe insertion hole.