Piston pump
A piston pump (10) for supplying pressure fluid into at least one vehicle brake, into a master cylinder, into a pressure fluid reservoir, or into a pressure fluid accumulator of a controlled vehicle brake system, is integrated into an accommodating member (3) in a simple and space-saving manner. A plurality of valve seats (38, 54) of non-return valves (32, 33, 36, 37) are kept as free as possible from pressing or attaching forces in that a sleeve (18, 19) has a radial flange for being secured in position between a closing member (52) and the accommodating member (3).
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The present invention relates to a piston pump for supplying pressure fluid into at least one vehicle brake, into a master cylinder, into a pressure fluid reservoir or into a pressure fluid accumulator of a controlled vehicle brake system.
A piston pump of this type is e.g. disclosed in DE 100 22 811 A1 and comprises, among others, a sleeve retained in a stepped bore. This sleeve is pressed into the stepped bore by a closing member that abuts axially on a bottom of the sleeve. It is disadvantageous in this type of construction that the pressing and attaching forces introduced into the sleeve may cause a deformation of a seat for a non-return valve. This jeopardizes the operational safety of the vehicle brake system.
A generic piston pump is described in DE 197 53 083 A1. A closing member bears in an axial direction directly against the sleeve, pressing it axially against a bore step. The forces introduced through the sleeve and a conical abutment surface of the sleeve in the area of the non-return valve can cause a deformation of the sleeve in the area of the valve seat.
In view of the above, an object of the invention is to disclose a means permitting an integration of a piston-pump subassembly into an accommodating member, while in particular valve seats of non-return valves can be retained so as to be free from pressing or attaching forces being due to the assembly and from resultant deformations.
SUMMARY OF THE INVENTIONAccording to the invention, this object is achieved in that the sleeve includes a radial flange, and in that the radial flange is compressed between the closing member and the accommodating member for securing the sleeve in position in an axial direction. This measure is used to retain the pump subassembly in the accommodating member, while the necessary attaching forces are introduced into the sleeve at a point spaced from the seat of non-return valves, thereby preventing that the sealing effect of the non-return valves is impaired.
In a favorable embodiment of the invention, the stepped bore has a bore step with a bore diameter that is designed larger than the radial flange so that an exclusively axial abutment of the radial flange prevails. This prevents an application of force at the periphery of the sleeve which causes out-of-true operation or deformations of the sleeve.
It is furthermore favorable that the sleeve includes a bowl-shaped portion which is used as a support for the resetting spring and has a cylindrical wall and a bottom on which one end of the resetting spring is abutting. This obviates the need for a separate assembly of a separate spring retainer in the accommodating member.
A portion of the sleeve can be substantially V-shaped or U-shaped in cross-section so that an indentation provided between the wall and a collar is used to accommodate the resetting spring, and an outside indentation formed by the collar accommodates a non-return valve in such a fashion that resetting spring, sleeve and non-return valve intersect at least in the area of the portion in a radial direction. An arrangement of the components involved that achieves especially short dimensions is thereby given, and a seat for a non-return valve can be provided in the bottom area of the sleeve. The seat is preferably provided at the collar.
Centering of the spring is enabled when the collar in the seat area has a substantially conical portion, the diameter of said portion corresponding basically to the diameter of the resetting spring and the portion engaging the resetting spring. The conicalness facilitates the placement in the event of an inexact feeding of components.
The mounting space requirement is furthermore reduced when the closing member has a bowl-shaped design and includes a wall and a bottom, and the bowl-shaped portion of the sleeve is accommodated in an inner space of the closing member, and an end surface of the wall maintains the radial flange in abutment on the bore step.
Essential parts of the piston pump, in particular the sleeve and the portion, due to the protuberances are formed as sheet-metal shaped parts being fastened in the area of the radial flange to the closing member by means of calked or pressed engagement.
In principle, the pump of the invention shows a good aspiration behavior, even at low temperatures of the pressure fluid, because the construction allows correspondingly expanded aspiration cross-sections especially as regards the channel routing and the piston configuration.
Further details of the invention can be taken from the following description making reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGSIn the drawings:
A preferably central stepped bore 5 of the accommodating member 3 accommodates a sealed roller bearing 6 of the drive shaft 7 whose free end is designed as an eccentric 8 projecting into a crank chamber 9 of the stepped bore 5. It is principally possible that the eccentric 8 is ground out directly at the drive shaft 7 or motor shaft, or is designed as a separate component and attached to the drive shaft. For an extended pump operation life the crank chamber 9 can be flooded with leakage fluid, especially with brake fluid, and a reservoir connected to the crank chamber 9 is used for the fluid take-up within the drive 2, the accommodating member 3 or the electronic control unit 4.
The eccentric 8 is equipped with a needle bearing 11 which is closed on one side by a bowl-shaped outside ring 12, the bowl bottom 13 thereof, with a wart-like projection, being movable into abutment on an end surface of the drive shaft in a punctual manner and with low friction. A bottom 14 of the crank chamber 9 has a ball 15 so that the bowl bottom 13 abuts with an outside surface remote from the motor shaft on the ball 15 in a low-friction fashion, and the outside ring 12 that can be rotated relative to the accommodating member 3 does not have any direct contact to the material of the accommodating member 3. This counteracts frictional stress of the accommodating member 3, without having to apply wear-resistant material coatings such as eloxal coatings onto walls of an accommodating member 3 made of aluminum.
As shown in
As can be seen, the stepped end of the piston 16 which is also split like a fork by at least one groove has a plate-shaped valve seat 38 whose cylindrical wall portion 39 is slipped at least partly onto the end 22. It also carries the guiding and sealing ring 26 on an outside surface. The valve seat 38 includes a stop 40 to secure the sealing ring 26 axially in position. A component 42 which acts additionally as a spring plate for a piston resetting spring 41 and a valve spring 45 or, like in
The piston resetting spring 41 extends through the entire displacement chamber 24 and bears with one end on an abutment 47 that is remote from the piston and also serves as a bottom for the sleeve. According to the embodiment of
Various measures are possible to support the valve spring 56 of the non-return valve 36. As can be seen in
In all embodiments the sleeve is retained by a closing member 52, 52′, 52″ in the stepped bore of the accommodating member 3. For this purpose, the closing member 52, 52′, 52″ is calked or clinched with the accommodating member 3, as is shown in the Figures. A clinched engagement implies in this context that the closing member 52, 52′, 52″ is made of a material harder than the accommodating member 3, and that the closing member 52, 52′, 52″ in the area of a bore wall is further provided with a contour producing a form lock by means of cold working between the components involved in the event of a relative displacement between closing member 52, 52′, 52″ and accommodating member 3.
In order to integrate the closing member 52 into the independently operable pump assembly even in the type of construction according to
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- 1 assembly
- 2 drive
- 3 accommodating member
- 4 control unit
- 5 stepped bore
- 6 roller bearing
- 7 drive shaft
- 8 eccentric
- 9 crank chamber
- 10 piston pump
- 11 needle bearing
- 12 outside ring
- 13 bowl bottom
- 14 bottom
- 15 ball
- 16 piston
- 17 piston
- 18 sleeve
- 19 sleeve
- 20 end
- 21 end
- 22 end
- 23 end
- 24 displacement chamber
- 25 displacement chamber
- 26 guiding ring
- 27 guiding ring
- 28 sealing assembly
- 29 sealing assembly
- 30 supply chamber
- 31 supply chamber
- 32 non-return valve
- 33 non-return valve
- 34 filter
- 35 filter
- 36 non-return valve
- 37 non-return valve
- 38 valve seat
- 39 wall portion
- 40 stop
- 41 resetting spring
- 42 component
- 43 leg
- 44 leg
- 45 valve spring
- 46 component portion
- 47 support
- 48 radial flange
- 49 wall
- 50 bottom area
- 51 radial flange
- 52 closing member
- 53 collar
- 54 seat
- 55 valve member
- 56 valve spring
- 57 retaining component
- 58 guiding portion
- 59 radial flange
- 60 retaining portion
- 61 stop
- 62 elevation
- 63 elevation
- 64 stepped bore
- 65 stepped bore
- 66 wall
- 67 end surface
- 68 bottom
- 69 bore step
- E inlet
- A outlet
- Ax axial direction
- R radial direction
Claims
1-9. (canceled)
10. A piston pump (10) for supplying pressure fluid for a controlled vehicle brake system, including the following features:
- a piston (16, 17) is movably arranged in a stepped bore (64) of an accommodating member (3) provided with a closing member (52);
- the piston (16, 17) is guided in a sleeve (18, 19) at least in sections;
- the sleeve (18, 19) comprises a non-return valve (32, 33, 36, 37) which is arranged coaxially to the piston (16, 17) and is used for the ventilation of a working chamber (24, 25) into which the piston (16, 17) plunges;
- a resetting spring (41) is provided within the sleeve (18, 19) between a support (47) and the piston (16, 17),
- wherein the sleeve (18, 19) includes a radial flange (51), and wherein the radial flange (51) is compressed between the closing member (52) and the accommodating member (3) for securing the sleeve (18, 19) axially in position.
11. The piston pump as claimed in claim 10,
- wherein the stepped bore (64) has a bore step (69) with a bore diameter designed to be larger than the radial flange (51) for an exclusively axial abutment of the radial flange (51).
12. The piston pump as claimed in claim 10,
- wherein the sleeve (18, 19) includes a bowl-shaped portion which is used as a support (47) for the resetting spring (41) and has a wall (49) and a bottom area (50) on which one end of the resetting spring (41) is abutting.
13. The piston pump as claimed in claim 12,
- wherein the portion of the sleeve (18, 19) is bulged to be substantially V-shaped or U-shaped in cross-section so that an indentation provided between the wall (49) and a collar (53) is used to accommodate the resetting spring, and wherein an outside indentation formed by the collar (53) accommodates a non-return valve (36, 37) in such a fashion that resetting spring (41), sleeve (18, 19) and non-return valve (36, 37) intersect each other at least in the area of the portion in a radial direction R.
14. The piston pump as claimed in claim 12,
- wherein the collar (53) in the seat area has a substantially conical portion, the diameter thereof corresponding basically to the diameter of the resetting spring (41), and wherein the portion engages the resetting spring (41).
15. The piston pump as claimed in claim 12,
- wherein the closing member (52) has a bowl-shaped design and includes a wall (66) with an end surface (67) and a bottom (68), and wherein the sleeve (18, 19) at least with the support (47) is accommodated in an inner space of the closing member (52), and wherein the end surface (67) retains the radial flange (51) in abutment on the bore step (69).
16. The piston pump as claimed in claim 10,
- wherein a seat (54) for a non-return valve (36, 37) is provided in a bottom area of the sleeve (18, 19).
17. The piston pump as claimed in claim 16,
- wherein the seat (54) is provided at the collar (53).
18. The piston pump as claimed in claim 16,
- wherein the sleeve (18, 19) and in particular the support (47) are designed as sheet-metal shaped parts, and wherein these are fastened in the area of the radial flange (51) to the closing member (52) by means of calked or pressed engagement.
Type: Application
Filed: Dec 12, 2003
Publication Date: Apr 26, 2007
Applicant:
Inventors: Dieter Dinkel (Schwalbach), Albrecht Otto (Schoneck), Hans-Georg Zentgraf (Russelsheim)
Application Number: 10/545,258
International Classification: F04B 53/12 (20060101);