Pump device
A pump device may include an eccentric member mounted on an output shaft in an eccentric manner, a cam mechanism which is engaged with the eccentric member to convert a motion of the output shaft into a radial direction and at least one pump body which includes a diaphragm that is moved in the radial direction in relation to the output shaft by the cam mechanism for performing a pumping operation.
The present invention claims priority under 35 U.S.C. § 119 to Japanese Application No. 2004-166205 filed Jun. 3, 2004, which is incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates to a pump device for circulating fluid. More specifically, the present invention relates to a pump device provided with a pump body utilizing a diaphragm.
BACKGROUND OF THE INVENTION A conventional circulating pump 100 has been known in which a plurality of pump bodies 102 are provided for sucking and compressing fluid by means of the operation of diaphragms 101 and the diaphragms 101 of the respective pump bodies 102 are disposed on the same plane as shown in
When the motor 103 is driven continuously and the rotation shaft 104 is rotated, the peripheral part of the cam plate 105 is moved in the axial direction of the rotation shaft 104 by the inclined end face of the rotation shaft 104. The up and down operations of the respective diaphragms 101 are performed by the movement in the axial direction of the cam plate 105. When the diaphragm 101 is pressed, the capacity of a pressure chamber 106 is decreased and fluid is sent in one direction by the operation of an inflow valve and an outflow valve.
However, in the above-mentioned circulating pump 100, the diaphragms 101 are disposed on the same plane and thus downsizing is difficult while maintaining the size of the pump body 102. Further, since the diaphragms 101 are disposed on the same plane, the diameter of the cam plate 105 has to be also enlarged when the diaphragm 101 is enlarged in order to increase the flow rate, and thus an extensive modification is required.
In addition, since the cam plate 105 is slightly inclined with respect to the disposing face of the diaphragm 101 and the motor 103 is continuously rotated, it is difficult to operate only one of the pump bodies 102 at a time. In other words, since the cam plate 105 is slightly inclined with respect to the disposing face of the diaphragm 101, adjacent pump bodies 102 are operated together. Therefore, it is difficult to operate only one of the pump bodies 102 at a time in order to obtain a little flow rate.
SUMMARY OF THE INVENTIONIn view of the problems described above, the present invention may advantageously provide a pump device that can be easily miniaturized and can obtain a little flow rate.
Thus, according to an embodiment of the present invention, there may be provided a pump device including a motor, an eccentric member which is mounted on an output shaft of the motor in an eccentric manner, a cam mechanism which engages with the eccentric member and converts into a motion in a radial direction of the output shaft, and a plurality of pump bodies each of which includes a diaphragm that is moved in the radial direction of the output shaft by the cam mechanism for performing a pumping operation.
According to an embodiment of the present invention, when a motor is driven, an eccentric member is rotated and a diaphragm is pressed through a cam mechanism to operate a pump body. Therefore, the pump device is operated and fluid is sucked or compressed.
In the pump device described above, a stepping motor may be preferably used as the motor. When a stepping motor is used, the cam mechanism may be controlled by a small angle, and at this time, only one of the plurality of pump bodies can be operated to obtain a little flow rate.
In accordance with an embodiment of the present invention, the cam mechanism may preferably include a contact ring which is rotatably mounted with respect to the eccentric member and, when the eccentric member is rotated, the contact ring makes the diaphragm move in the radial direction of the output shaft while the contact ring relatively rotates with respect to the eccentric member. When the cam mechanism is constructed such that the contact ring makes the diaphragm move in the radial direction while the contact ring is relatively rotated with respect to the eccentric member, the contact ring does not perform the operation of pushing while rotating with respect to the diaphragm and thus the movement of the diaphragm in the radial direction can be stably performed.
In accordance with an embodiment of the present invention, a pressure chamber may be provided which is closed by the diaphragm and is in communication with an inflow passage and an outflow passage and a projecting part for moving the diaphragm is formed on an opposite side to the pressure chamber with respect to the diaphragm. According to the construction described above, when the pressure of the pressure chamber increases with the diaphragm being pushed by the contact ring through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm is returned, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
In accordance with an embodiment of the present invention, the projecting part of the diaphragm may be preferably covered with a fluorine coating or material having an abrasion resistance property and a low friction coefficient for the improvement of durability and the reduction of contact resistance.
In accordance with an embodiment of the present invention, a plurality of pump bodies may be four pump bodies which are disposed around the cam mechanism at every 90 degrees with an equal distance, and only one of the four pump bodies is preferably operated by the contact ring at a time. When only one of the four pump bodies can be operated by the contact ring at a time, an output with a little flow rate can be easily obtained.
In accordance with an embodiment of the present invention, the cam mechanism may include a slider which is relatively rotatably mounted with respect to the eccentric member. According to the construction described above, when the eccentric member is rotated, the diaphragm is moved in the radial direction of the output shaft while the slider is relatively rotated with respect to the eccentric member.
In accordance with an embodiment of the present invention, a pressure chamber may be provided which is closed by the diaphragm moved by the slider and is in communication with an inflow passage and an outflow passage, and a projecting part for moving the diaphragm is formed on an opposite side to the pressure chamber with respect to the diaphragm. According to the construction described above, when the pressure of the pressure chamber increases with the diaphragm being pushed by the slider through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm is returned by the slider through the projecting part, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
According to the pump device described above in accordance with an embodiment of the present invention, since the cam mechanism makes the diaphragm move in the radial direction of the output shaft, the diaphragms are not required to be disposed on the same plane as the conventional example, and thus the downsizing of the pump device can be easily attained.
Further, when a stepping motor is used as the motor, the cam mechanism can be controlled by a little angle and thus a little flow rate can be obtained by means of operating only one pump at a time. As a result, the applicable scope of the pump device can be extended.
Other features and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings that illustrate, by way of example, various features of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGSEmbodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:
FIGS. 1(A) and 1(B) are views showing a pump device in accordance with an embodiment of the present invention.
FIGS. 20(A), 20(B) and 20(C) are plan views showing embodiments in which different number of pump bodies are disposed.
FIGS. 21(A) and 21(B) are views showing a cam mechanism in accordance with another embodiment of the present invention.
Several embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
A pump device 1 in accordance with an embodiment of the present invention is shown in
The motor 2 is a stepping motor. The motor 2 is mounted on a support plate 11 with a screw. The inner ring 22 of a ball bearing 12 is mounted on the eccentric member 4, for example, by press fitting. On the tip end of the output shaft 3 of the motor 2 are fixed a washer for pressing the ball bearing 12 and a slit ring 13 with a screw 14. The eccentric member 4 is fixed to the output shaft 3 of the motor 2 with a screw 49.
The cam mechanism 5 is provided with a slide guide 15 which is integrally formed on the support plate 11, a slider 16 which is slidable in a direction perpendicular to an axial direction (radial direction), and a bearing holder 17 for accommodating the ball bearing 12 as shown in
The slider 16 is formed in a ring shape and provided with slide guide side protruded parts 19 which are formed to protrude on the slide guide 15 side in the radial direction and bearing holder side protruded parts 20 which are formed to protrude on the bearing holder 17 side in the radial direction at different angular positions from those of the slide guide side protruded parts 19. The bearing holder 17 is formed in a cylindrical shape. On the end face on the slider 16 side are provided with guide grooves 21 formed in the radial direction with which the bearing holder side protruded parts 20 of the slider 16 are slidably engaged. The outer ring 23 of the ball bearing 12 is fitted to the bearing holder 17.
Further, as shown in
The pump bodies 7 through 10 are constructed in the same manner. Each of the pump bodies 7 through 10 is provided with a pressure chamber 28 constructed in a case 27 and a diaphragm 6 formed to close the pressure chamber 28 as shown in
A projecting part 33 is formed at the center of the opposite side face of the diaphragm 6 to the pressure chamber 28 for pressing and transforming the diaphragm 6. Fluorine coating is preferably applied on the projecting part 33 of the diaphragm 6 to enhance durability and reduce contact resistance. Alternatively, the projecting part 33 is covered with material having an abrasion resistance property and a low friction coefficient to enhance durability and reduce contact resistance.
An inflow passage 34 and an outflow passage 35 are formed in the pressure chamber 28 so as to be in communication with the outside. An L-shaped inflow valve groove 36 is formed on the way of the inflow passage 34 and an L-shaped inflow valve 37 is inserted into the inflow valve groove 36 and fixed. The inflow valve 37 has a mounting part 37a and a valve part 37b. The valve part 37b is in tight contact with the opposite side face of the inflow valve groove 36 to the pressure chamber 28. Therefore, when the diaphragm is pushed and the pressure of the volume chamber increases, the fluid is flown out from the pressure chamber 28. At this time, the valve part 37b is brought into tight contact with the wall of the inflow valve groove 36 and the flow is stopped. When the diaphragm is returned and the pressure of the volume chamber decreases, the fluid is flown into the pressure chamber 28. At this time, the valve part 37b moves away from the wall of the inflow valve groove 36 and the fluid flows. In other words, the inflow valve 37 constructs a so-called check valve. A spot facing 39 for mounting an O-ring 38 is formed in the inlet port of the inflow passage 34.
An L-shaped outflow valve groove 40 is formed on the way of the outflow passage 35 and an L-shaped outflow valve 41 is inserted into the outflow valve groove 40 and fixed. The outflow valve 41 has a mounting part 41a and a valve part 41b. The valve part 41b is in tight contact with the face of the outflow valve groove 40 on the pressure chamber 28 side. Therefore, when the diaphragm is returned and the pressure of the volume chamber decreases, the fluid is flown into the pressure chamber 28. At this time, the valve part 41b is brought into tight contact with the wall of the outflow valve groove 40 and the flow is stopped. When the diaphragm is pushed and the pressure of the volume chamber increases, the fluid is flown out from the pressure chamber 28. At this time, the valve part 41b moves away from the wall of the outflow valve groove 40 and the fluid flows. In other words, the outflow valve 41 constructs a so-called check valve. An outflow pipe 42 is connected to the outlet port of the outflow passage 35.
The respective valve parts 37b, 41b of the inflow valve 37 and the outflow valve 41 are formed of an extremely thin elastic member which is capable of being deformed with a prescribed little pressure. Thus, the valve can be operated with a small pressure loading. In addition, since a check valve structure is used which can be mounted only by inserting to the respective valve grooves 36, 40, a valve which is easily assembled with a high degree of sensibility and reliability can be obtained and the valve is capable of coping with a small flow rate.
As shown in
As shown in
The outflow pipe 42 of each of the pump bodies 7 through 10 is penetrated through the through hole of the support plate 11 of the cam mechanism 5. An O-ring 38 is fitted to the spot facing 39 at the inlet port of each of the inflow passages 34. In addition, a flow passage cover 43 is provided on the side faces of the pump bodies 7 through 10 which are opposite to the cam mechanism 5. The flow passage cover 43 is provided with holes 44 each of which is formed at the position corresponding to the spot facing 39 of each of the pump bodies 7 through 10 and pipe lines 45 each of which is penetrated in its side face direction from the hole 44 as shown in
A circuit board 46 is disposed on the inner face side of the flow passage cover 43 as shown in
The operation of the above-mentioned pump device 1 will be described below.
When the motor 2 is driven, the inner ring 22 of the ball bearing 12 is rotated by the eccentric member 4. The outer ring 23 of the ball bearing 12 performs a circling movement with a radius of the eccentric dimension of the eccentric member 4. Accordingly, the bearing holder 17 and the contact ring 24 also perform a circling movement with the radius of the eccentric dimension of the eccentric member 4. Since the cam mechanism 5 is operated by the output shaft 3 through the eccentric member 4, the contact ring 24 performs a circling movement with the radius of the eccentric dimension of the eccentric member 4 which is fixed to the output shaft 3. Therefore, even though the contacting point of the contact ring 24 with the diaphragm is away from the rotation center, the contact speed “V” of the contact ring 24 with the diaphragm becomes very slow in comparison with the case when a rigid cam fixed to the rotating shaft is operated to directly move the diaphragm. As a result, the contact PV (product of pressure P and velocity V) can be extremely reduced in comparison with the case that the cam mechanism 5 is directly mounted on the output shaft 3, and thus the durability can be improved.
When the motor 2 is rotated, the contact ring 24 presses and then releases successively the projecting part 33 of the diaphragm 6 of each of the pump bodies 7 through 10 as shown in
The rotating position of the output shaft 3 is detected by the photo interrupter 47. Since the motor 2 is a stepping motor 2, the output shaft 3 can be rotated in movements of a specific or arbitrary angle with respect to each of the pump bodies 7 through 10. The movements of the diaphragms 6 in the respective pump bodies 7 through 10 do not simultaneously occur at two of the pump bodies as shown by the solid line in
As described above, the motor 2 is a stepping motor. Therefore, normal or forward and reverse rotations are easily performed with a high degree of controllability and the accuracy of flow rate of the carried fluid can be enhanced by the pump device 1. Further, since the motor 2 is a stepping motor, the motor is not activated when operation is not required and thus an energy saving pump can be attained.
Although the present invention has been shown and described with reference to specific embodiments, various changes and modifications will be apparent to those skilled in the art from the teachings herein. For example, in an embodiment of the present invention, the diaphragm 6, the inflow valve 37 and the outflow valve 41 are formed in a separated manner. However, the present invention is not limited to this embodiment and they may be integrally formed as shown in
In addition, in an embodiment of the present invention, the assembling of the respective pump bodies 7 through 10 is performed by using a screw, and further the assembling of the respective pump bodies 7 through 10 and the support plate 11 is also performed by using a screw. However, the present invention is not limited to this embodiment and ultrasonic, wave welding or adhesion may be used. Further, in an embodiment of the present invention, the photo interrupter 47 is used to detect the rotational position of the output shaft 3. However, the present invention is not limited to this embodiment and well-known rotation detecting means such as a Hall element or an MR (magneto-resistance effect) element may be used.
Further, in an embodiment of the present invention, four pump bodies 7 through 10 are provided. However, the present invention is not limited to this embodiment and, for example, the number of pump bodies may be set to be one through three as shown in FIGS. 20(A), 20(B) and 20(C), or set to be any arbitrary number. In this case, the displacement dimension of the diaphragm 6 can be sufficiently obtained with a smaller number of pump bodies. In addition, in an embodiment of the present invention, the pump bodies 7 through 10 are arranged to be constructed in only one stage in the axial direction of the output shaft 3. However, the present invention is not limited to this embodiment and a plurality of stages of the pump bodies may be arranged in the axial direction of the output shaft 3.
In an embodiment of the present invention, two types of free rotating members are arranged in the cam mechanism 5, in other words, the ball bearing 12 and the contact ring 24 are arranged in the cam mechanism 5. However, the present invention is not limited to this embodiment and the free rotating members are not necessarily provided in the cam mechanism 5. For example, the cam mechanism 5 comprising of a cam member as shown in FIGS. 21(A) and 21(1B) may be used. Further, a cam mechanism as shown in
In addition, in an embodiment of the present invention, the bearing holder 17 presses the diaphragm 6 through the contact ring 24 by using the combination of the slide guide 15, the slider 16 and the bearing holder 17. However, the present invention is not limited to this embodiment and, instead of using the slide guide 15, the slider 16 and the bearing holder 17, a pair of sliders 50A, 50B may be arranged around the periphery of the ball bearing 12 such that the sliders 50A, 50B are engaged with the eccentric member 4 in the eccentric direction to reciprocate in a linear manner as shown in
In an embodiment of the present invention, the diaphragm 6 is used. However, the present invention is not limited to this embodiment and a tube may be used.
While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.
The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims
1. A pump device comprising:
- a motor;
- an eccentric member which is mounted on an output shaft of the motor in an eccentric manner;
- a cam mechanism which is engaged with the eccentric member to convert a motion of the output shaft into a radial direction; and
- at least one pump body, which includes a diaphragm that is moved in the radial direction in relation to the output shaft by the cam mechanism for performing a pumping operation.
2. The pump device according to claim 1, wherein the motor is a stepping motor.
3. The pump device according to claim 1, wherein the cam mechanism includes a contact ring which is rotatably mounted with respect to the eccentric member and, when the eccentric member is rotated, the contact ring makes the diaphragm move in the radial direction relative to the output shaft while the contact ring relatively rotates with respect to the eccentric member.
4. The pump device according to claim 1, further comprising:
- a pressure chamber which is closed by the diaphragm and is in communication with an inflow passage and an outflow passage; and
- a projecting part for moving the diaphragm which is formed on an opposite side to the pressure chamber with respect to the diaphragm,
- wherein, when the pressure of the pressure chamber increases with the diaphragm being pushed by the contact ring through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm returns, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
5. The pump device according to claim 4, wherein a fluorine coating is applied to the projecting part of the diaphragm.
6. The pump device according to claim 4, wherein the projecting part of the diaphragm is covered with material having an abrasion resistance property and a low friction coefficient.
7. The pump device according to claim 3, wherein the plurality of pump bodies are four pump bodies disposed around the cam mechanism at every 90 degrees with an equal distance, and only one of the four pump bodies is operated by the contact ring at a time.
8. The pump device according to claim 1, further comprising a slider which is provided in the cam mechanism and relatively rotatably mounted with respect to the eccentric member,
- wherein, when the eccentric member is rotated, the diaphragm is moved in the radial direction of the output shaft while the slider is relatively rotated with respect to the eccentric member.
9. The pump device according to claim 8, further comprising:
- a pressure chamber which is closed by the diaphragm and is in communication with an inflow passage and an outflow passage; and
- a projecting part for moving the diaphragm which is formed on an opposite side to the pressure chamber with respect to the diaphragm,
- wherein, when the pressure of the pressure chamber increases with the diaphragm being pushed by the slider through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm is returned by the slider through the projecting part, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
10. A pump device comprising:
- an eccentric member mounted on a output shaft;
- a cam mechanism which is engaged with the eccentric member to convert a motion of the output shaft into a radial direction; and
- at least one pump body comprising a diaphragm that is moved in the radial direction in relation to the output shaft by the cam mechanism for performing a pumping operation.
11. The pump device according to claim 10, wherein the output shaft moves in discrete steps of rotation.
12. The pump device according to claim 10 wherein the cam mechanism includes a contact ring which is rotatably mounted with respect to the eccentric member and is structured so that when the eccentric member is rotated, the contact ring makes the diaphragm move in the radial direction relative to the output shaft while the contact ring relatively rotates with respect to the eccentric member.
13. The pump device according to claim 10, further comprising:
- a pressure chamber which is closed by the diaphragm and is in communication with an inflow passage and an outflow passage; and
- a projecting part for moving the diaphragm which is formed on an opposite side to the pressure chamber with respect to the diaphragm,
- wherein, when the pressure of the pressure chamber increases with the diaphragm being pushed by the contact ring through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm returns, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
14. The pump device according to claim 13, wherein a fluorine coating is applied to the projecting part of the diaphragm.
15. The pump device according to claim 13, wherein the projecting part of the diaphragm is covered with material having an abrasion resistance property and a low friction coefficient.
16. The pump device according to claim 12, wherein the plurality of pump bodies are four pump bodies disposed around the cam mechanism at every 90 degrees with an equal distance, and only one of the four pump bodies is operated by the contact ring at a time.
17. The pump device according to claim 10, further comprising a slider which is provided in the cam mechanism and relatively rotatably mounted with respect to the eccentric member,
- wherein, when the eccentric member is rotated, the diaphragm is moved in the radial direction of the output shaft while the slider is relatively rotated with respect to the eccentric member.
18. The pump device according to claim 15, further comprising:
- a pressure chamber which is closed by the diaphragm and is in communication with an inflow passage and an outflow passage; and
- a projecting part for moving the diaphragm which is formed on an opposite side to the pressure chamber with respect to the diaphragm,
- wherein, when the pressure of the pressure chamber increases with the diaphragm being pushed by the slider through the projecting part, fluid flows out from the pressure chamber and, when the diaphragm is returned by the slider through the projecting part, the pressure of the pressure chamber decreases to make fluid flow into the pressure chamber.
Type: Application
Filed: Jun 2, 2005
Publication Date: Dec 8, 2005
Inventors: Kenji Muramatsu (Nagano), Motohiro Iizawa (Nagano)
Application Number: 11/143,523