Pump device

Abstract

A bearing is located with movement of an outer race in the longitudinal direction of a drive shaft being restricted, and the drive shaft is fixed to an inner race 51c with the press fit, so that, it is possible to prevent the drive shaft from escaping. In addition, the inner race is longer than the outer race. Therefore, it is possible to obtain sufficient strength of the press fit of the drive shaft in the inner race 51c while suppressing the size of the outer race (in other words, suppressing the size of the pump device). As a consequence, the size of the pump device can be suppressed while increasing reliability of the function for preventing the drive shaft from escaping.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objective, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings. In the drawings:

FIG. 1 is a schematic diagram showing a vehicle brake device having a pump device according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the pump device including two rotary pumps;

FIG. 3A is a perspective view of a third cylinder;

FIG. 3B is a frontal view of the third cylinder; and

FIG. 4 is a cross-sectional view taken along the IV-IV line in FIG. 2.

Claims

1. A pump device comprising: a first case;a drive shaft inserted in the first case;a first bearing for supporting the drive shaft allowing the drive shaft to rotate; anda first pump located in the first case, the pump being driven by the drive shaft to draw in and discharge fluid;wherein:the first bearing includes: an inner race into which the drive shaft is inserted with a press fit;an outer race located in the first case with movement of the outer race in the longitudinal direction of the drive shaft restricted; anda rolling body inserted between the inner race and the outer race while having capability of restricting relative movement between the inner race and the outer race in the longitudinal direction of the drive shaft; anda length of the inner race in the longitudinal direction of the drive shaft is larger than a length of the outer race in the longitudinal direction of the drive shaft.

2. The pump device according to claim 1, wherein: the outer race is inserted into the first case with a loose fit and is restricted in the movement of the outer race in the longitudinal direction of the drive shaft caused by a surface of the first case, the surface facing the longitudinal direction of the drive shaft and being in touch with the outer race.

3. The pump device according to claim 1, comprising a plurality of bearings for supporting the drive shaft allowing the drive shaft to rotate, the plurality of bearings including the first bearing, wherein:each of one or more of the plurality of bearings includes: a first inner race into which the drive shaft is inserted with a press fit;a first outer race located in the first case with movement of the first outer race in the longitudinal direction of the drive shaft restricted, the outer race being larger than the first inner race in length in the longitudinal direction of the drive shaft; anda first rolling body inserted between the first inner race and the first outer race while having capability of restricting relative movement between the first inner race and the first outer race in the longitudinal direction of the drive shaft; andeach of the other one or more of the plurality of bearings includes: a second inner race; anda second outer race being as large as the second inner race in length in the longitudinal direction of the drive shaft.

4. The pump device according to claim 2, comprising a plurality of bearings for supporting the drive shaft allowing the drive shaft to rotate, the plurality of bearings including the first bearing, wherein:each of one or more of the plurality of bearings includes: a first inner race into which the drive shaft is inserted with a press fit;a first outer race located in the first case with movement of the first outer race in the longitudinal direction of the drive shaft restricted, the outer race being larger than the first inner race in length in the longitudinal direction of the drive shaft; anda first rolling body inserted between the first inner race and the first outer race while having capability of restricting relative movement between the first inner race and the first outer race in the longitudinal direction of the drive shaft; andeach of the other one or more of the plurality of bearings includes: a second inner race; anda second outer race being as large as the second inner race in length in the longitudinal direction of the drive shaft.

5. The pump device according to claim 1, comprising a plurality of bearings for supporting the drive shaft allowing the drive shaft to rotate, the plurality of bearings including the first bearing, wherein:each of one or more of the plurality of bearings includes: a first inner race into which the drive shaft is inserted with a press fit;a first outer race located in the first case with movement of the first outer race in the longitudinal direction of the drive shaft restricted, the outer race being larger than the first inner race in length in the longitudinal direction of the drive shaft; anda first rolling body inserted between the first inner race and the first outer race while having capability of restricting relative movement between the first inner race and the first outer race in the longitudinal direction of the drive shaft; andeach of the other one or more of the plurality of bearings includes a second inner race into which the drive shaft is inserted with a loose fit.

6. The pump device according to claim 2, comprising a plurality of bearings for supporting the drive shaft allowing the drive shaft to rotate, the plurality of bearings including the first bearing, wherein:each of one or more of the plurality of bearings includes: a first inner race into which the drive shaft is inserted with a press fit;a first outer race located in the first case with movement of the first outer race in the longitudinal direction of the drive shaft restricted, the outer race being larger than the first inner race in length in the longitudinal direction of the drive shaft; anda first rolling body inserted between the first inner race and the first outer race while having capability of restricting relative movement between the first inner race and the first outer race in the longitudinal direction of the drive shaft; andeach of the other one or more of the plurality of bearings includes a second inner race into which the drive shaft is inserted with a loose fit.

7. The pump device according to claim 1, comprising: a housing including a concave portion;a second case located coaxially with the first case, the case being movable relative to the first case in the longitudinal direction of the drive shaft; anda spring means located between the first case and the second case, the spring means biasing the first case and second case so that the first case and second case get apart from each other,wherein:the first case and the second case are inserted into the concave portion in a manner that the first case is closer to the bottom of the concave portion than the second case is;the second case is pressed against the first case in a direction from the entrance of the concave portion to the first case; andthe outer race is in touch with a surface of the first case, the surface facing a bottom surface of the concave portion and is in touch with the bottom surface of the concave portion, so that movement of the outer race is restricted in the longitudinal direction of the drive shaft.

8. The pump device according to claim 2, comprising: a housing including a concave portion;a second case located coaxially with the first case, the case being movable relative to the first case in the longitudinal direction of the drive shaft; anda spring means located between the first case and the second case, the spring means biasing the first case and second case so that the first case and second case get apart from each other,wherein:the first case and the second case are inserted into the concave portion in a manner that the first case is closer to the bottom of the concave portion than the second case is;the second case is pressed against the first case in a direction from the entrance of the concave portion to the first case; andthe outer race is in touch with a surface of the first case, the surface facing a bottom surface of the concave portion and is in touch with the bottom surface of the concave portion, so that movement of the outer race is restricted in the longitudinal direction of the drive shaft.

9. The pump device according to claim 4, comprising: a housing including a concave portion;a second case located coaxially with the first case the case being movable relative to the first case in the longitudinal direction of the drive shaft; anda spring means located between the first case and the second case, the spring means biasing the first case and second case so that the first case and second case get apart from each other,wherein:the first case and the second case are inserted into the concave portion in a manner that the first case is closer to the bottom of the concave portion than the second case is;the second case is pressed against the first case in a direction from the entrance of the concave portion to the first case; andthe outer race is in touch with a surface of the first case, the surface facing a bottom surface of the concave portion and is in touch with the bottom surface of the concave portion, so that movement of the outer race is restricted in the longitudinal direction of the drive shaft.

10. The pump device according to claim 6, comprising: a housing including a concave portion;a second case located coaxially with the first case, the case being movable relative to the first case in the longitudinal direction of the drive shaft; anda spring means located between the first case and the second case, the spring means biasing the first case and second case so that the first case and second case get apart from each other,wherein:the first case and the second case are inserted into the concave portion in a manner that the first case is closer to the bottom of the concave portion than the second case is;the second case is pressed against the first case in a direction from the entrance of the concave portion to the first case; andthe outer race is in touch with a surface of the first case, the surface facing a bottom surface of the concave portion and is in touch with the bottom surface of the concave portion, so that movement of the outer race is restricted in the longitudinal direction of the drive shaft.

11. The pump device according to claim 9, wherein, the first pump is a gear pump and at least one of the plurality of bearings is a ball bearing.

12. The pump device according to claim 10, wherein, the first pump is a gear pump and at least one of the plurality of bearings is a ball bearing.

13. The pump device according to claim 1, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves; anda second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves.

14. The pump device according to claim 13, wherein: the first pump and the first side cylinder are in touch with each other so that a space between the first pump and the first side cylinder is sealed; andthe second pump and the second side cylinder are in touch with each other so that a space between the second pump and the second side cylinder is sealed.

15. The pump device according to claim 3, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.

16. The pump device according to claim 5, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.

17. The pump device according to claim 7, comprising: a second pump installed in the first case, the second pump being driven by the drive shaft to draw in and discharge fluid, the second pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.the annular groove is located radially outside of the axis seal member.

18. The pump device according to claim 8, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the pump being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.

19. The pump device according to claim 11, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.

20. The pump device according to claim 12, comprising: a second pump installed in the first case, the pump being driven by the drive shaft to draw in and discharge fluid, the pump being aligned with the first pump in the longitudinal direction of the drive shaft,wherein:the first case includes: a middle cylinder located between the first pump and the second pump, the middle cylinder being faced by a surface of the first pump and a surface of the second pump;a first side cylinder located at the opposite side of the first pump from the middle cylinder, the side cylinder being faced by the other surface of the first pump; anda second side cylinder located at the opposite side of the second pump from the middle cylinder, the side cylinder being faced by the other surface of the second pump;annular grooves are formed respectively on surfaces of the middle cylinder, the surfaces facing respectively the first pump and the second pump;a first seal member sealing a space between the first pump and the middle cylinder is located within one of the annular grooves;a second seal member sealing a space between the second pump and the middle cylinder is located within another one of the annular grooves;the middle cylinder includes a center hole into which the drive shaft is inserted;an axis seal member is located at the center hole and seals a space between the middle cylinder and the drive shaft; andone of the annular grooves is located radially outside of the axis seal member.