Electric pump and control device

Abstract

The present invention provides an electric pump and control device capable of determining when an abnormality occurs in the sliding shaft support section due to a lack of fluid. [Solution] The electric pump comprises a motor unit having a shaft rotatable about a rotation axis, a pump unit connected to one axial end of the shaft and driven by the motor unit to pump fluid, a housing that houses the motor unit and the pump unit, and a control device that controls the operation of the motor unit. The control device determines an abnormality due to a lack of fluid in the sliding shaft support based on a first fluctuation value Vf1, which is the fluctuation value of the rotation speed of the shaft, a second fluctuation value Vf2, which is the fluctuation value of the current supplied to the motor unit, or a third fluctuation value Vf3, which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotation speed of the shaft is constant.

Description

[Technical Field]

[0001] The present invention relates to an electric pump and a control device. [Background technology]

[0002] A pump is known in which a shaft that transmits the rotational torque of the rotor to the pump is rotatably supported by an inner cylindrical portion of the housing (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-090277 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In the pump described above, if the amount of fluid such as oil interposed between the shaft and the inner cylinder of the main body decreases, the lubrication performance between the shaft and the inner cylinder of the main body by the fluid decreases, and the frictional force between the shaft and the inner cylinder of the main body increases. If the pump continues to operate in this condition, there is a risk that the pump will fail due to wear on at least one of the shaft and the inner cylinder of the main body, and seizure of the shaft against the inner cylinder of the main body.

[0005] One aspect of the present invention aims to provide an electric pump and control device that can determine when an abnormality occurs due to a lack of fluid in the sliding shaft support section, in view of the above circumstances. [Means for solving the problem]

[0006] One embodiment of the electric pump of the present invention comprises a motor unit having a shaft rotatable about a rotation axis, a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid, a housing housing the motor unit and the pump unit, and a control device for controlling the operation of the motor unit. The housing has a motor housing for housing the motor unit, a pump housing for housing the pump unit, and a sliding shaft support for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support. The control device determines an abnormality due to a shortage of the fluid in the sliding shaft support based on a first fluctuation value, which is the fluctuation value of the rotation speed of the shaft, a second fluctuation value, which is the fluctuation value of the current supplied to the motor unit, or a third fluctuation value, which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotation speed of the shaft is constant.

[0007] One aspect of the control device of the present invention is a control device for controlling the operation of an electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; and a housing housing the motor unit and the pump unit. The housing has a motor housing unit for housing the motor unit, a pump housing unit for housing the pump unit, and a sliding shaft support unit for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support unit. An abnormality due to a shortage of the fluid in the sliding shaft support unit is determined based on a first fluctuation value, which is the fluctuation value of the rotation speed of the shaft, a second fluctuation value, which is the fluctuation value of the current supplied to the motor unit, or a third fluctuation value, which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotation speed of the shaft is constant. [Effects of the Invention]

[0008] According to one aspect of the present invention, an electric pump and control device can determine if an abnormality has occurred in the sliding shaft support due to a lack of fluid.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing the electric pump of the first embodiment. [Figure 2] FIG. 2 is a plan view of the annular wall portion of the first embodiment as viewed from one axial side. [Figure 3] FIG. 3 is a plan view of the pump cover of the first embodiment as viewed from the other axial side. [Figure 4] FIG. 4 is a block diagram schematically showing the control device of the first embodiment. [Figure 5] FIG. 5 is a first diagram showing an example of the first variation value, the second variation value, and the third variation value in the electric pump of the first embodiment. [Figure 6] FIG. 6 is a second diagram showing an example of the first variation value, the second variation value, and the third variation value in the electric pump of the first embodiment. [Figure 7] FIG. 7 is a third diagram showing an example of the first variation value, the second variation value, and the third variation value in the electric pump of the first embodiment. [Figure 8] FIG. 8 is a flowchart showing a method for determining an abnormality of the sliding shaft support portion of the first embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing the electric pump of a modification of the first embodiment. [Figure 10] FIG. 10 is a flowchart showing a method for determining an abnormality of the electric pump of the second embodiment. [Figure 11] FIG. 11 is a first diagram showing an example of the rotational speed of the shaft in the electric pump of the second embodiment. [Figure 12] FIG. 12 is a second diagram showing an example of the rotational speed of the shaft in the electric pump of the second embodiment.

Embodiments for Carrying Out the Invention

[0010] The following description of an electric pump according to an embodiment of the present invention will be made with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and modifications can be made as appropriate within the scope of the technical concept of the present invention. Furthermore, in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0011] Each figure shows the XYZ coordinate system as appropriate. The direction in which the Y-axis extends is the direction in which the rotation axis J of the embodiment described below extends. The rotation axis J shown in each figure is a virtual axis. In the following description, the direction in which the rotation axis J extends, that is, the direction parallel to the Y-axis, is called the "axial direction". The side of the axial direction in which the Y-axis arrow points (+Y side) is called the "one side of the axial direction", and the side of the axial direction opposite to the side in which the Y-axis arrow points (-Y side) is called the "other side of the axial direction". The radial direction centered on the rotation axis J is simply called the "radial direction". The circumferential direction centered on the rotation axis J is simply called the "circumferential direction".

[0012] The direction in which the Z-axis extends is the vertical direction when the electric pump of the embodiment described below is attached. In the following description, the vertical direction when the electric pump is attached will simply be referred to as the "vertical direction". The side of the vertical direction in which the Z-axis arrow points (+Z side) will be referred to as the "upper side".

[0013] The direction in which the X-axis extends is the left-right direction when the electric pump of the embodiment described below is installed. The left-right direction is perpendicular to both the axial direction and the up-down direction. In the following description, the left-right direction when the electric pump is installed will simply be referred to as the "left-right direction". The side of the left-right direction in which the X-axis arrow points (+X side) will be referred to as the "left side", and the side of the left-right direction opposite to the side in which the X-axis arrow points (-X side) will be referred to as the "right side".

[0014] The orientation of the electric pump in the vertical direction described below is just one example. Furthermore, "upper," "right," and "left" are merely names used to describe the relative positions of the parts, and other arrangements are also possible.

[0015] <First Embodiment> Figure 1 is a cross-sectional view showing the electric pump 1 of this embodiment. The electric pump 1 is attached to, for example, a mounting device 5 installed on a vehicle. In this embodiment, the electric pump 1 is housed inside the housing 5a of the mounting device 5. The mounting device 5 may be an automatic transmission or a drive device that drives the axle of a vehicle. The electric pump 1 of this embodiment is an electric pump that supplies fluid R to the mounting device 5. In this embodiment, fluid R is oil. Fluid R may be another liquid such as water. The electric pump 1 is connected to a flow path provided in the mounting device 5 via an inlet 19b and a discharge port 19c. The electric pump 1 comprises a housing 10, a motor unit 20, a pump unit 40, and a control device 70.

[0016] The housing 10 is substantially cylindrical in shape and extends in the axial direction. The housing 10 houses the motor unit 20, the pump unit 40, and the control device 70, respectively. The housing 10 has a housing body 11, a lid 17, a pump cover 19, a motor housing 10a, and a pump housing 10c. In this embodiment, the housing body 11, the lid 17, and the pump cover 19 are separate components.

[0017] The housing body 11 is substantially cylindrical in shape, extending axially with respect to the rotation axis J. The housing body 11 houses the motor section 20 and the pump section 40 inside. The housing body 11 has a cylindrical section 12, an annular wall section 13, and a sliding shaft support section 15. In other words, the housing 10 has a sliding shaft support section 15.

[0018] The cylindrical portion 12 is substantially cylindrical in shape, extending axially with respect to the rotation axis J. The cylindrical portion 12 has openings on both sides, one axial side and the other axial side. The cylindrical portion 12 surrounds the motor portion 20 and the pump portion 40 from the radial outside. A cover portion 17 is fixed to the other axial end of the cylindrical portion 12. A pump cover 19 is fixed to the one axial end of the cylindrical portion 12. The cylindrical portion 12 is provided with a locking groove portion 12a and a recess portion 12c. The cylindrical portion 12 has a first inner surface portion 12e.

[0019] The locking groove 12a is a groove that recesses radially inward from the outer circumferential surface of the cylindrical portion 12. The locking groove 12a is provided on the other axial side of the cylindrical portion 12. The locking groove 12a is provided along the outer circumferential surface of the cylindrical portion 12 for a full circumference.

[0020] The recess 12c is recessed in the axial direction from a part of the surface of the cylindrical portion 12 facing the other axial direction. The recess 12c is provided on the right side (-X side) of the surface of the cylindrical portion 12 facing the other axial direction. The recess 12c is open to both the radially inward and radially outward directions. This creates a small gap between the housing body 11 and the lid 17. This gap connects the internal space of the cylindrical portion 12 to the external space of the housing 10.

[0021] The first inner surface portion 12e is the portion of the inner surface of the cylindrical portion 12 that is on one axial side of the annular wall portion 13. The first inner surface portion 12e surrounds the pump portion 40 from the radially outer side. Viewed from the axial direction, the first inner surface portion 12e has a substantially circular shape that is eccentric with respect to the rotation axis J.

[0022] The annular wall portion 13 is located inside the cylindrical portion 12. The annular wall portion 13 is located on one axial side of the motor portion 20 and on the other axial side of the pump portion 40. The annular wall portion 13 is substantially circular with respect to the rotation axis J. The portion of the outer circumferential surface of the annular wall portion 13 on one axial side is connected to the inner circumferential surface of the cylindrical portion 12 over a full circumference. The annular wall portion 13 has opposing surfaces 13a.

[0023] The opposing surface 13a is the outer surface of the annular wall portion 13 that faces in one axial direction. The opposing surface 13a faces the pump portion 40 in the axial direction. The opposing surface 13a is provided with a first suction side groove portion 13c and a first discharge side groove portion 13e.

[0024] The first intake groove 13c and the first discharge groove 13e are grooves that are recessed from the opposing surface 13a to the other side in the axial direction. The first intake groove 13c and the first discharge groove 13e each open to one side in the axial direction. As shown in Figure 2, the first intake groove 13c and the first discharge groove 13e each are arc-shaped grooves that extend in the circumferential direction. The first intake groove 13c and the first discharge groove 13e are located at different positions in the circumferential direction relative to each other. The first intake groove 13c and the first discharge groove 13e face each other radially across the axis of rotation J.

[0025] As shown in Figure 1, the sliding shaft support portion 15 is located inside the cylindrical portion 12. The sliding shaft support portion 15 is located, for example, on one axial side of the motor portion 20 and on the other axial side of the pump portion 40. The sliding shaft support portion 15 is substantially cylindrical in shape, extending axially with respect to the rotation axis J. The other axial end of the sliding shaft support portion 15 is located on the other axial side of the annular wall portion 13. In the axial direction, the position of the one axial end of the sliding shaft support portion 15 is approximately the same as the position of the opposing surface 13a. A shaft 23, which will be described later, passes through the sliding shaft support portion 15 in the axial direction. As shown in Figure 2, a part of the outer circumferential surface of the sliding shaft support portion 15 is connected to the inner circumferential surface of the annular wall portion 13. The sliding shaft support portion 15 has a support surface 15a and a first communication groove portion 15c.

[0026] The support surface 15a is the inner circumferential surface of the sliding shaft support portion 15. Viewed from the axial direction, the support surface 15a is substantially circular in shape. As shown in Figure 1, the support surface 15a is in contact with the outer circumferential surface of the shaft 23, which will be described later. The support surface 15a supports the shaft 23 so that it can rotate about the rotation axis J. In this embodiment, the sliding shaft support portion 15 functions as a sliding bearing that supports the shaft 23.

[0027] The first communication groove 15c is a groove that recesses from the surface of the sliding shaft support 15 facing one axial side to the other axial side. The first communication groove 15c is provided on the right side (-X side) of the surface of the sliding shaft support 15 facing one axial side. As shown in Figure 2, the first communication groove 15c extends linearly along the radial direction. The radially inner end of the first communication groove 15c opens into the interior of the sliding shaft support 15. The radially outer end of the first communication groove 15c opens into the first discharge side groove 13e. Thus, the first communication groove 15c connects the interior of the sliding shaft support 15 and the interior of the first discharge side groove 13e. Therefore, a portion of the fluid R supplied to the pump section 40 can be supplied between the shaft 23 and the support surface 15a, which will be described later, via the first discharge side groove 13e and the first communication groove 15c. This allows the fluid R to be suitably interposed between the shaft 23 and the sliding shaft support portion 15. Therefore, the fluid R can suitably lubricate both the shaft 23 and the sliding shaft support portion 15.

[0028] As shown in Figure 1, the lid portion 17 is substantially cylindrical in shape, projecting axially around the rotation axis J. The lid portion 17 has an opening on one axial side. The lid portion 17 is fixed to the other axial end of the housing body portion 11. The lid portion 17 closes the other axial opening of the cylindrical portion 12. The internal space of the lid portion 17 and the internal space of the cylindrical portion 12 are connected to each other. The control device 70 is housed inside the lid portion 17. In this embodiment, the lid portion 17 is made of resin, for example. The lid portion 17 may be made of other materials such as metal. The lid portion 17 has a peripheral wall portion 17a and a substrate cover 17e.

[0029] The peripheral wall portion 17a is substantially annular in shape with the rotation axis J as its center. The peripheral wall portion 17a surrounds the control device 70 from the radially outer side. The peripheral wall portion 17a is provided with a plurality of claw portions 17b and groove portions 17c.

[0030] Each of the multiple claw portions 17b extends from the circumferential wall portion 17a in one axial direction. The claw portions 17b are arranged in a line along the circumferential direction. Each claw portion 17b has a projection that protrudes radially inward from one axial end. The projections of each claw portion 17b are located inside the locking groove portion 12a. As a result, the lid portion 17 is fixed to the housing body portion 11.

[0031] The groove 17c is a groove that recesses radially inward from the outer circumferential surface of the peripheral wall 17a. The groove 17c extends circumferentially along the outer circumferential surface of the peripheral wall 17a. An O-ring 91 is fitted into the groove 17c. The O-ring 91 is in contact with the inner surface of the housing portion 5a of the equipment to be mounted 5. In this way, the O-ring 91 seals the space between the housing 10 and the equipment to be mounted 5.

[0032] The substrate cover 17e is positioned on the other axial side of the peripheral wall portion 17a. The substrate cover 17e is substantially disc-shaped with respect to the axis of rotation J. In this embodiment, the substrate cover 17e is adhesively fixed to the other axial end of the peripheral wall portion 17a. The substrate cover 17e covers the control device 70 from the other axial side. In this way, the substrate cover 17e protects the control device 70.

[0033] The pump cover 19 is substantially disc-shaped with respect to the axis of rotation J. The pump cover 19 is positioned on one axial side of the pump section 40. The pump cover 19 covers the pump section 40 from one axial side. The pump cover 19 is fixed to one axial end of the housing body 11. The pump cover 19 closes the opening on one axial side of the cylindrical section 12. The pump cover 19 has an intake section 19a, a discharge port 19c, a second intake side groove 19e, a second discharge side groove 19f, an opposing recess 19g, and a second communication groove 19j.

[0034] The suction section 19a is substantially cylindrical in shape and protrudes from the pump cover 19 in one axial direction. The suction section 19a is provided with an inlet 19b. The inlet 19b is located on the tip surface of the suction section 19a. As will be described later, the inlet 19b is connected to the bottom surface of the second suction groove section 19e. Through the inlet 19b, the fluid R from outside the electric pump 1 is drawn into the housing 10.

[0035] The discharge port 19c is an opening provided on the surface of the pump cover 19 facing one axial direction. The fluid R compressed in the pump section 40 is discharged to the outside of the electric pump 1 through the discharge port 19c.

[0036] The second suction groove 19e and the second discharge groove 19f are grooves that are recessed in one axial direction from the surface of the pump cover 19 facing the other axial direction. The second suction groove 19e and the second discharge groove 19f each open to the other axial direction. As shown in Figure 3, the second suction groove 19e and the second discharge groove 19f each are arc-shaped grooves that extend in the circumferential direction. The second suction groove 19e and the second discharge groove 19f are each provided radially outward from the opposing recess 19g. The second suction groove 19e and the second discharge groove 19f are provided at different circumferential positions relative to each other. The second suction groove 19e and the second discharge groove 19f face each other radially across the rotation axis J.

[0037] An intake port 19b is open at the bottom of the second intake groove 19e. As a result, the inside of the second intake groove 19e is connected to the intake port 19b. As shown in Figure 1, when viewed from the axial direction, the second intake groove 19e overlaps with the first intake groove 13c. As shown in Figures 2 and 3, when viewed from the axial direction, the second intake groove 19e and the first intake groove 13c have substantially the same shape.

[0038] As shown in Figure 3, a discharge port 19c is open at the bottom of the second discharge channel 19f. As a result, the inside of the second suction channel 19e is connected to the discharge port 19c. As shown in Figure 1, when viewed from the axial direction, the second discharge channel 19f overlaps with the first discharge channel 13e. As shown in Figures 2 and 3, when viewed from the axial direction, the second discharge channel 19f and the first discharge channel 13e have substantially the same shape.

[0039] As shown in Figure 1, the opposing recess 19g is a hole recessed in one axial direction from the surface of the pump cover 19 facing the other axial side. As shown in Figure 3, when viewed from the axial direction, the opposing recess 19g is a substantially circular hole centered on the axis of rotation J. The shape of the opposing recess 19g is not limited to this embodiment. The opposing recess 19g is provided radially inward from the second suction groove 19e and the second discharge groove 19f. As shown in Figure 1, the opposing recess 19g faces the shaft 23, which will be described later, in the axial direction.

[0040] The second communication groove 19j is a groove that recesses in the axial direction from the surface of the pump cover 19 facing the other axial direction. The second communication groove 19j is provided on the left side (+X side) of the surface of the pump cover 19 facing the other axial direction. As shown in Figure 3, the second communication groove 19j extends linearly along the radial direction. The radially inner end of the second communication groove 19j opens into the opposing recess 19g. The radially outer end of the second communication groove 19j opens into the second suction side groove 19e. As a result, the inside of the opposing recess 19g and the inside of the second suction side groove 19e are connected via the second communication groove 19j. In this embodiment, the portion of the second suction side groove 19e that connects to the suction port 19b is located above (+Z side) the portion that connects to the second communication groove 19j.

[0041] As shown in Figure 1, the motor housing 10a is the portion of the housing 10 that houses the motor unit 20 and the control device 70, respectively. In this embodiment, the motor housing 10a is composed of the portion of the cylindrical unit 12 on the axial side of the annular wall unit 13, the annular wall unit 13, the sliding shaft support unit 15, and the cover unit 17. The pump housing 10c is the portion of the housing 10 that houses the pump unit 40. In this embodiment, the pump housing 10c is composed of the portion of the cylindrical unit 12 on one axial side of the annular wall unit 13, the annular wall unit 13, the sliding shaft support unit 15, and the pump cover 19. The pump housing 10c is located on one axial side of the motor housing 10a. The pump housing 10c and the motor housing 10a are separated by the annular wall unit 13 and the sliding shaft support unit 15.

[0042] The motor unit 20 is housed inside the housing body 11. More specifically, the motor unit 20 is housed inside the motor housing 10a. In the axial direction, the motor unit 20 is positioned on one axial side of the control device 70 and on the other axial side of the pump unit 40. The motor unit 20 includes a rotor 21, a stator 30, and a terminal unit 38.

[0043] The rotor 21 is rotatable about the axis of rotation J. The rotor 21 has a rotor core 21a, a magnet 21b, and a shaft 23. That is, the motor unit 20 has a shaft 23. The rotor core 21a is substantially annular about the axis of rotation J. The magnet 21b is fixed to the rotor core 21a.

[0044] The shaft 23 is substantially cylindrical in shape and extends axially about the rotation axis J. In this embodiment, the shaft 23 is a hollow shaft. The shaft 23 extends across the motor housing 10a and the pump housing 10c. The other axial end of the shaft 23 is located inside the motor housing 10a. The one axial end of the shaft 23 is located inside the pump housing 10c. The shaft 23 passes axially through the inside of the rotor core 21a and the inside of the sliding shaft support 15, respectively. The other axial portion of the shaft 23 is fixed to the inner circumferential surface of the rotor core 21a. This allows the shaft 23 to rotate about the rotation axis J. The axial central portion of the shaft 23 is rotatably supported about the rotation axis J by the support surface 15a of the sliding shaft support 15. In other words, the sliding shaft support 15 supports the shaft 23. The one axial end of the shaft 23 is connected to the pump section 40. As a result, the rotational torque of the rotor 21 is transmitted to the pump section 40. The shaft 23 has a hollow section 23h. The hollow section 23h is open on both sides, one axial side and the other axial side. This connects the inside of the motor housing section 10a and the inside of the opposing recess 19g via the hollow section 23h.

[0045] The stator 30 is positioned radially outward from the rotor 21. The stator 30 faces the rotor 21 with a radial gap between them. The stator 30 has a stator core 31, an insulator 32, and a coil section 33.

[0046] The stator core 31 surrounds the rotor core 21a from the radially outer side. The outer circumferential surface of the stator core 31 is fixed to the inner circumferential surface of the cylindrical portion 12. The stator core 31 has a substantially annular core back portion 31a and a plurality of tooth portions 31b that protrude radially inward from the inner circumferential surface of the core back portion 31a. Although not shown in the figure, each of the plurality of tooth portions 31b is arranged at intervals along the circumferential direction. Coil portions 33 are mounted on the tooth portions 31b via insulators 32.

[0047] The coil section 33 is composed of wound coil wires. As shown in Figure 4, the coil section 33 has a U-phase coil 33U, a V-phase coil 33V, and a W-phase coil 33W. Different phase currents (U-phase current, V-phase current, and W-phase current) are supplied to each of the U-phase coil 33U, V-phase coil 33V, and W-phase coil 33W from the control device 70. Coil wires (not shown) are drawn out from the coil section 33.

[0048] Although not shown in the diagram, the coil wire drawn from the coil section 33 is connected to the terminal unit 38 shown in Figure 1. In the axial direction, the terminal unit 38 is positioned between the stator 30 and the control device 70. The terminal unit 38 has multiple terminals. These terminals include the U-phase terminal 39U, V-phase terminal 39V, and W-phase terminal 39W shown in Figure 4. The terminal unit 38 electrically connects the coil section 33 and the control device 70 via the multiple terminals 39U, 39V, and 39W.

[0049] As shown in Figure 1, the pump unit 40 is housed inside the housing body 11. More specifically, the pump unit 40 is housed inside the pump housing 10c. The pump unit 40 is positioned on one axial side of the motor unit 20. The pump unit 40 is connected to one axial end of the shaft 23. The pump unit 40 is driven by the motor unit 20 to draw in fluid R from outside the electric pump 1, compress the drawn-in fluid R, and discharge it outside the electric pump 1. The pump unit 40 is driven by the motor unit 20 to pump the fluid R. The pump unit 40 in this embodiment is a trochoid pump. The pump unit 40 has an inner rotor 41 and an outer rotor 42.

[0050] The inner rotor 41 is an annular shape extending in the axial direction. One axial portion of the shaft 23 is inserted into the interior of the inner rotor 41. The shaft 23 is fixed to the inner circumferential surface of the inner rotor 41. As a result, the pump unit 40 is connected to one axial end of the shaft 23. Power from the rotor 21 is transmitted to the inner rotor 41. This allows the inner rotor 41 to rotate around the rotation axis J.

[0051] The outer rotor 42 is positioned radially outward from the inner rotor 41. The outer rotor 42 is annular in shape, surrounding the inner rotor 41 from the radial outside. The outer circumferential surface of the outer rotor 42 is in radial contact with the first inner surface 12e. The first inner surface 12e supports the outer rotor 42 so that it can rotate around the axis of rotation J.

[0052] Each of the inner rotor 41 and the outer rotor 42 has a trochoidal tooth profile (not shown). The trochoidal tooth profile of the inner rotor 41 and the trochoidal tooth profile of the outer rotor 42 mesh at one point in the circumferential direction. When the inner rotor 41 rotates integrally with the shaft 23 around the axis of rotation J, the outer rotor 42 rotates eccentrically around the axis of rotation J while sliding on the first inner surface 12e.

[0053] The interior of the second intake groove 19e and the interior of the first intake groove 13c are connected axially via the gap G between the inner rotor 41 and the outer rotor 42. In the following description, the internal spaces of the second intake groove 19e and the first intake groove 13c that are connected to each other will be referred to as the intake chamber A2. The intake chamber A2 is connected to the intake port 19b.

[0054] The interiors of the second discharge channel 19f and the first discharge channel 13e are connected axially via the gap G between the inner rotor 41 and the outer rotor 42. In the following description, the internal spaces of the second discharge channel 19f and the first discharge channel 13e that are connected to each other will be referred to as the compression chamber A1. The compression chamber A1 is connected to the discharge port 19c.

[0055] When the electric pump 1 is driven, the gap G between the inner rotor 41 and the outer rotor 42 moves around the axis of rotation J. As a result, when the pressure in the intake chamber A2 decreases, fluid R flows into the intake chamber A2 through the intake port 19b, as shown by arrow F1 in Figure 1. Furthermore, when the gap G moves circumferentially, fluid R moves from the intake chamber A2 to the compression chamber A1, as shown by arrow F2 in Figure 1. As a result, when the pressure in the compression chamber A1 increases, fluid R in the compression chamber A1 is pumped to the outside of the electric pump 1 through the discharge port 19c, as shown by arrow F3 in Figure 1. The fluid R pumped into the housing 5a of the equipment to be installed is then pumped through an opening 5b provided in the equipment to be installed into a flow path (not shown) in the equipment to be installed 5. In this way, the electric pump 1 supplies fluid R to the equipment to be installed 5.

[0056] As described above, the first communication groove 15c connects the inside of the sliding shaft support 15 to the inside of the first discharge side groove 13e. In other words, the first communication groove 15c connects the inside of the sliding shaft support 15 to the compression chamber A1. When the electric pump 1 is driven, as described above, when the pressure in the compression chamber A1 increases, as shown by arrow F4 in Figure 1, a portion of the fluid R in the compression chamber A1 flows into the motor housing 10a through the first communication groove 15c and the inside of the sliding shaft support 15. As a result, fluid R is supplied to the inside of the motor housing 10a, and fluid R is also supplied between the shaft 23 and the support surface 15a. In other words, the pump unit 40 supplies fluid R to the sliding shaft support 15. Therefore, fluid R can be suitably interposed between the shaft 23 and the sliding shaft support 15. As a result, the fluid R can suitably lubricate the shaft 23 and the sliding shaft support 15, thereby reducing the frictional force between the shaft 23 and the sliding shaft support 15. Therefore, the rotational speed Rv of the shaft 23 can be stabilized. In the following description, the "rotational speed Rv of the shaft 23" may be simply referred to as "rotational speed Rv". Note that the rotational speed Rv of the shaft 23 is the same as the rotational speed of the rotor 21.

[0057] As shown by arrow F5 in Figure 1, a portion of the fluid R pumped into the housing 5a of the equipment to be mounted flows into the motor housing 10a through the recess 12c provided in the cylindrical portion 12. This supplies fluid R to the inside of the motor housing 10a. Also, as described above, a portion of the fluid R in the compression chamber A1 flows into the motor housing 10a by passing through the first communication groove 15c and the sliding shaft support portion 15. As a result, fluid R is stored inside the motor housing 10a. The fluid R in the motor housing 10a circulates within the motor housing 10a due to the rotation of the rotor 21, cooling the motor portion 20 and the control device 70, respectively. This prevents the temperature of the motor portion 20 and the control device 70 from becoming too high, thereby improving the operational stability of the motor portion 20 and the control device 70.

[0058] As described above, the inside of the motor housing 10a and the inside of the opposing recess 19g provided in the pump cover 19 are connected via the hollow portion 23h of the shaft 23. Also, as described above, the inside of the opposing recess 19g and the inside of the second suction side groove 19e are connected via the second communication groove 19j. As a result, the inside of the motor housing 10a is connected to the suction chamber A2. Therefore, as described above, when the pressure in the suction chamber A2 decreases when the electric pump 1 is driven, a portion of the fluid R inside the motor housing 10a flows into the suction chamber A2 via the hollow portion 23h, the opposing recess 19g, and the second communication groove 19j, as shown by arrow F6 in Figure 1. The fluid R that has flowed into the suction chamber A2 is pumped out of the electric pump 1 through the discharge port 19c, along with the fluid R that flowed into the suction chamber A2 from the suction port 19b.

[0059] As described above, the fluid R interposed between the shaft 23 and the sliding shaft support 15 lubricates both the shaft 23 and the sliding shaft support 15. Therefore, if the shaft 23 continues to rotate with a small amount of fluid R interposed between the shaft 23 and the sliding shaft support 15, the frictional force between the shaft 23 and the sliding shaft support 15 increases, causing wear on at least one of the shaft 23 and the sliding shaft support 15. If wear particles from at least one of the shaft 23 and the sliding shaft support 15 become lodged between the inner rotor 41 and the outer rotor 42, the pump unit 40 may lock up. Furthermore, if the amount of wear on the sliding shaft support 15 increases, the shaft 23 may tilt. If the inner rotor 41 tilts as a result, the frictional force between the inner circumferential surface of the pump housing 10c and the outer rotor 42 may increase. If wear on the inner surface of the pump housing 10c creates a gap between the pump housing 10c and the outer rotor 42, the pressure of the fluid R in the compression chamber A1 will decrease, which may reduce the pump efficiency. In the following description, wear on at least one of the shaft 23 and the sliding shaft support 15, locking of the pump unit 40, and a decrease in pump efficiency may be referred to as failures of the electric pump 1.

[0060] The control device 70 controls the current supplied to the coil section 33 of the stator 30 based on control signals transmitted from the main control unit 6 of the vehicle, the operation of each part of the electric pump 1, and the current supplied to each part of the electric pump 1. In this way, the control device 70 controls the operation of the motor section 20. In other words, the control device 70 controls the operation of the electric pump 1. The main control unit 6 is, for example, an on-board ECU (Electronic Control Unit) mounted on a vehicle. As shown in Figure 1, the control device 70 is located on the other axial side of the motor section 20. As described above, the control device 70 is electrically connected to the motor section 20 via a terminal unit 38. The control device 70 has a circuit board 71. As shown in Figure 4, the control device 70 has a motor drive circuit 72, a control unit 75, a storage unit 76, a first detection unit 77, a second detection unit 78, and a third detection unit 79.

[0061] As shown in FIG. 1, the circuit board 71 is in a plate shape extending in a direction orthogonal to the axial direction. The circuit board 71 is electrically connected to the coil portion 33 of the stator 30 via the terminal unit 38. As shown in FIG. 4, a motor drive circuit 72, a control unit 75, a storage unit 76, a first detection unit 77, a second detection unit 78, and a third detection unit 79 are mounted on the circuit board 71, respectively.

[0062] The motor drive circuit 72 is a circuit that supplies current to the motor unit 20. The motor drive circuit 72 converts the direct current supplied from the external power source 95 into a three-phase alternating current and supplies it to the motor unit 20. In the present embodiment, the external power source 95 is, for example, a battery mounted on a vehicle. The motor drive circuit 72 includes an upper-arm switch Q UL , UH , , ,

[0064] for the U phase, an upper-arm switch Q VH for the V phase, an upper-arm switch Q WH for the W phase, a lower-arm switch Q UL for the U phase, a lower-arm switch Q VL for the V phase, and a lower-arm switch Q WL for the W phase. In the present embodiment, each arm switch is, for example, an N-channel type MOS-FET.

[0063] The drain terminals of the upper-arm switch Q UH for the U phase, the drain terminal of the upper-arm switch Q VH for the V phase, and the drain terminal of the upper-arm switch Q WH [[ID=​​​​​​​​​​​​​It is electrically connected to the drain terminal and electrically connected to the U-phase terminal 39U via the U-phase connection line 35U. V-phase upper arm switch Q VH The source terminal is the V-phase lower arm switch Q. VL It is electrically connected to the drain terminal and electrically connected to the V-phase terminal 39V via the V-phase connection line 35V. W-phase upper arm switch Q WH The source terminal is the W-phase lower arm switch Q. WL It is electrically connected to the drain terminal and electrically connected to the W-phase terminal 39W via the W-phase connection line 35W.

[0065] U-phase upper arm switch Q UH The gate terminal, V-phase upper arm switch Q VH The gate terminal and the W-phase upper arm switch Q WH Each of the gate terminals is electrically connected to the control unit 75. Also, the U-phase lower arm switch Q UL The gate terminal, V-phase lower arm switch Q VL The gate terminal and the W-phase lower arm switch Q WL Each of the gate terminals is also electrically connected to the control unit 75.

[0066] The motor drive circuit 72 in this embodiment is an inverter composed of a three-phase full-bridge circuit having three upper arm switches and three lower arm switches. The motor drive circuit 72 converts the DC current supplied from the external power supply 95 into a three-phase AC voltage by switching control of each arm switch by the control unit 75, and supplies it to the respective coils 33U, 33V, and 33W of each phase.

[0067] The first detection unit 77 detects the voltage applied to the coils 33U, 33V, and 33W of each phase and inputs the detection result to the control unit 75. In this embodiment, the control device 70 has three first detection units 77. One end of each first detection unit 77 is electrically connected to different connecting wires 35U, 35V, and 35W. The other end of each first detection unit 77 is grounded. Although not shown in the figures, each first detection unit 77 is electrically connected to the control unit 75. The control unit 75 calculates the rotational speed Rv of the shaft 23 based on the back electromotive force generated in the U-phase coil 33U, V-phase coil 33V, and W-phase coil 33W that are not supplied with current from the motor drive circuit 72.

[0068] The second detection unit 78 detects the current supplied to the motor unit 20 and inputs the detected current value Im to the control unit 75. In this embodiment, the second detection unit 78 is, for example, a shunt resistor. One end of the second detection unit 78 is electrically connected to the source terminal of each of the three lower arm switches. The other end of the second detection unit 78 is electrically connected to the negative terminal of the external power supply 95. Furthermore, one end of the second detection unit 78 is electrically connected to the control unit 75. A voltage proportional to the current supplied to the motor unit 20 appears between the terminals of the second detection unit 78. The voltage between the terminals of the second detection unit 78 is input to the control unit 75 as a current value Im, which represents the current supplied to the motor unit 20.

[0069] The third detection unit 79 detects the voltage applied to the control device 70 and inputs the detected voltage value Vc to the control unit 75. One end of the third detection unit 79 is electrically connected to the positive terminal of the external power supply 95. The other end of the third detection unit 79 is electrically connected to the negative terminal of the external power supply 95. Although not shown in the diagram, the third detection unit 79 is electrically connected to the control unit 75.

[0070] The control unit 75 is a microprocessor such as an MCU (Microcontroller Unit). The control unit 75 receives a rotation speed command signal CS1 from the main control unit 6. Based on the rotation speed command signal CS1, the control unit 75 calculates the target rotation speed TRv of the shaft 23. In the following description, the target rotation speed TRv of the shaft 23 may be simply referred to as "target rotation speed TRv". As will be described later, when the control unit 75 determines that there is an abnormality due to a deficiency of fluid R in the sliding shaft support 15, it sends an abnormality determination signal Sa to the main control unit 6. In the following description, the abnormality due to a deficiency of fluid R in the sliding shaft support 15 may be simply referred to as "abnormality of the sliding shaft support". Based on the abnormality determination signal Sa, the main control unit 6 sends a rotation time command signal CS2 to the control unit 75. Based on the rotation time command signal CS2, the control unit 75 calculates a second predetermined period P2, which is the time from determining the abnormality of the sliding shaft support 15 until the operation of the motor unit 20 is stopped. In this embodiment, the second predetermined period P2 is, for example, 10 seconds or less.

[0071] As described above, the control unit 75 receives the back electromotive force generated in the coil that is not supplied with current from the motor drive circuit 72 from the first detection unit 77. The control unit 75 also calculates the rotational speed Rv based on this back electromotive force. The control unit 75 controls the rotational speed Rv by controlling the motor drive circuit 72 based on the rotational speed Rv and the target rotational speed TRv. Specifically, the control unit 75 determines the switching duty cycle of each arm switch necessary to match the rotational speed Rv to the target rotational speed TRv, and controls the switching of each arm switch with the determined switching duty cycle. As a result, a three-phase AC current is supplied to the motor unit 20 that matches the rotational speed Rv to the target rotational speed TRv. In other words, the control device 70 controls the current supplied to the motor unit 20 so that the rotational speed Rv of the shaft 23 matches the target rotational speed TRv.

[0072] As described above, the control unit 75 receives the current value Im, which is the current supplied to the motor unit 20, from the second detection unit 78. As described above, the control unit 75 receives the voltage value Vc, which is the voltage applied to the control device 70, from the third detection unit 79. Based on these, the control device 70 acquires the rotation speed Rv, the current value Im, and the voltage value Vc, respectively.

[0073] Figure 5 is the first figure showing an example of the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 in the electric pump 1 of this embodiment. The uppermost graph in Figure 5 shows the change in the fluid amount MR, which is the amount of fluid R interposed between the shaft 23 and the sliding shaft support part 15. In this embodiment, we will describe the case in which the fluid amount MR stabilizes at a sufficient amount from time T0 to time T3, and then monotonically decreases after time T3. The decrease in the fluid amount MR occurs, for example, when foreign matter clogs the first communication groove part 15c (see Figure 1), causing a decrease in the amount of fluid R supplied from the pump part 40 to the sliding shaft support part 15. When the fluid amount MR decreases, the shaft 23 and the support surface 15a are more likely to come into direct contact, so the frictional force between the shaft 23 and the sliding shaft support part 15 increases.

[0074] The second graph from the top in Figure 5 shows the change in the rotational speed Rv of the shaft 23 calculated by the control unit 75. The rotational speed Rv oscillates around the target rotational speed TRv. In this embodiment, the fluctuation value of the rotational speed Rv of the shaft 23 during the first predetermined period P1 is called the first fluctuation value Vf1. The control device 70 calculates the first fluctuation value Vf1 based on the rotational speed Rv. The first fluctuation value Vf1 correlates with the rotational speed Rv of the shaft 23, i.e., the target rotational speed TRv. From time T0 to time T3, when the fluid amount MR is stable at a sufficient amount, the fluid R can suitably lubricate the shaft 23 and the sliding shaft support part 15, thereby reducing the frictional force between the shaft 23 and the sliding shaft support part 15. As a result, the rotational speed Rv of the shaft 23 is stable, and the first fluctuation value Vf1 is small. In contrast, from time T3 onward, when the fluid amount MR decreases, the frictional force between the shaft 23 and the sliding shaft support part 15 increases, as described above. As a result, the rotational speed Rv becomes unstable after time T3, and the amplitude of the rotational speed Rv increases. In other words, as the fluid volume MR decreases, the first fluctuation value Vf1 increases. Therefore, the control device 70 can determine an abnormality in the sliding shaft support 15 based on the first fluctuation value Vf1.

[0075] Furthermore, when the control unit 75 determines an abnormality in the sliding shaft support unit 15 based on the first fluctuation value Vf1, it is preferable that the target rotational speed TRv during the first predetermined period P1 is constant. This suppresses the inclusion of fluctuations in the rotational speed Rv caused by adjusting the target rotational speed TRv to a different speed in the first fluctuation value Vf1. Therefore, the control unit 75 can accurately determine an abnormality in the sliding shaft support unit 15 based on the first fluctuation value Vf1.

[0076] The first predetermined period P1 is preferably 1 second or more and 3 seconds or less. This prevents the first predetermined period P1 from becoming too long, allowing for quick detection of abnormalities in the sliding shaft support 15. In this embodiment, the first predetermined period P1 is 2 seconds. The first predetermined period P1 may be shorter or longer than 2 seconds, as long as it allows for quick detection of abnormalities in the sliding shaft support 15.

[0077] The third graph from the top in Figure 5 shows the change in the current value Im, which is the current supplied to the motor unit 20. In this embodiment, the fluctuation value of the current value Im during the first predetermined period P1 is called the second fluctuation value Vf2. The control device 70 calculates the second fluctuation value Vf2 based on the current value Im. From time T0 to time T3, when the fluid volume MR is stable at a sufficient amount, the second fluctuation value Vf2 is small. This is because, as described above, the rotational speed Rv of the shaft 23 is stable. In other words, the second fluctuation value Vf2 correlates with the rotational speed Rv of the shaft 23, i.e., the target rotational speed TRv. In contrast, from time T3 onward, when the fluid volume MR decreases, the second fluctuation value Vf2 increases. This is because, as described above, when the fluid volume MR decreases, the rotational speed Rv becomes unstable. In other words, when the fluid volume MR decreases, the second fluctuation value Vf2 increases. Therefore, the control device 70 can determine an abnormality in the sliding shaft support unit 15 based on the second fluctuation value Vf2.

[0078] The bottom graph in Figure 5 shows the change in the voltage value Vc, which is the voltage applied to the control device 70. In this embodiment, the fluctuation value of the voltage value Vc during the first predetermined period P1 is called the third fluctuation value Vf3. The control device 70 calculates the third fluctuation value Vf3 based on the voltage value Vc. From time T0 to time T3, when the fluid volume MR is stable at a sufficient amount, the third fluctuation value Vf3 is small. This is because, as described above, the rotational speed Rv of the shaft 23 is stable. In other words, the third fluctuation value Vf3 correlates with the rotational speed Rv of the shaft 23, i.e., the target rotational speed TRv. In contrast, from time T3 onward, when the fluid volume MR decreases, the third fluctuation value Vf3 increases. This is because, as described above, when the fluid volume MR decreases, the rotational speed Rv becomes unstable. In other words, when the fluid volume MR decreases, the third fluctuation value Vf3 increases. Therefore, the control device 70 can determine an abnormality in the sliding shaft support 15 based on the third fluctuation value Vf3.

[0079] As shown in Figure 4, the control unit 75 has a determination unit 75a. That is, the control device 70 has a determination unit 75a. In this embodiment, the determination unit 75a is part of the control unit 75. In this embodiment, the determination unit 75a determines a first determination value Vj1, a second determination value Vj2, and a third determination value Vj3 based on the target rotational speed TRv. The first determination value Vj1 is a threshold value of the first fluctuation value Vf1 used by the control device 70 to determine an abnormality in the sliding shaft support unit 15. In this embodiment, if the first fluctuation value Vf1 is less than the first determination value Vj1, the control device 70 determines that no abnormality has occurred in the sliding shaft support unit 15 and continues the operation of the motor unit 20. On the other hand, as shown in Figure 5, if the first fluctuation value Vf1 is greater than or equal to the first determination value Vj1, the control device 70 determines that there is an abnormality in the sliding shaft support unit 15 due to a deficiency of fluid R.

[0080] The second determination value Vj2 is a threshold value for the second fluctuation value Vf2 used by the control device 70 to determine an abnormality in the sliding shaft support section 15. In this embodiment, if the second fluctuation value Vf2 is less than the second determination value Vj2, the control device 70 determines that no abnormality has occurred in the sliding shaft support section 15 and continues the operation of the motor section 20. Figure 6 is a second diagram showing an example of the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 in the electric pump 1 of this embodiment. As shown in Figure 6, if the second fluctuation value Vf2 is greater than or equal to the second determination value Vj2, the control device 70 determines that there is an abnormality in the sliding shaft support section 15 due to a deficiency of fluid R.

[0081] The third determination value Vj3 is a threshold value for the third fluctuation value Vf3 used by the control device 70 to determine an abnormality in the sliding shaft support section 15. In this embodiment, if the third fluctuation value Vf3 is less than the third determination value Vj3, the control device 70 determines that no abnormality has occurred in the sliding shaft support section 15 and continues the operation of the motor section 20. Figure 7 is a third figure showing an example of the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 in the electric pump 1 of this embodiment. As shown in Figure 7, if the third fluctuation value Vf3 is greater than or equal to the third determination value Vj3, the control device 70 determines that there is an abnormality in the sliding shaft support section 15 due to a deficiency of fluid R.

[0082] The storage unit 76 includes a non-volatile memory that stores programs and various setting data necessary for the control unit 75 to execute various processes, and a volatile memory used as a temporary storage location for data when the control unit 75 executes various processes. The non-volatile memory is, for example, EEPROM (Electrically Erasable Programmable Read-Only Memory) or flash memory. The volatile memory is, for example, RAM (Random Access Memory). The storage unit 76 may be provided outside the control unit 75 or may be built into the control unit 75. The storage unit 76 is connected to the control unit 75 in a communicative manner via a communication bus (not shown). The control unit 75 performs abnormality detection of at least the sliding shaft support unit 15 according to a program pre-stored in the storage unit 76.

[0083] Figure 8 is a flowchart showing the method for determining abnormalities in the sliding shaft support section 15 in this embodiment. The method for determining abnormalities in the sliding shaft support section 15 in this embodiment is a method for determining abnormalities in the sliding shaft support section 15 due to a deficiency of fluid R. When the control device 70 starts the operation of the motor section 20, the determination unit 75a determines a first determination value Vj1, a second determination value Vj2, and a third determination value Vj3 based on the target rotational speed TRv (S01). In this embodiment, each time the target rotational speed TRv is changed, the determination unit 75a determines the first determination value Vj1, the second determination value Vj2, and the third determination value Vj3 based on the target rotational speed TRv.

[0084] Next, the control device 70 calculates the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 based on the target rotational speed TRv of the shaft 23 during the first predetermined period P1 in which the target rotational speed TRv of the shaft 23 is constant (S02).

[0085] Next, if the first fluctuation value Vf1 is less than the first determination value Vj1 (S03), the second fluctuation value Vf2 is less than the second determination value Vj2 (S04), and the third fluctuation value Vf3 is less than the third determination value Vj3 (S05), the control device 70 determines that there is no shortage of fluid volume MR and continues the operation of the motor unit 20. From this point onward, the control device 70 repeats the above operation.

[0086] In response, the control device 70 determines that there is an abnormality in the sliding shaft support 15 if the first fluctuation value Vf1 is greater than or equal to the first determination value Vj1 (S03), if the second fluctuation value Vf2 is greater than or equal to the second determination value Vj2 (S04), or if the third fluctuation value Vf3 is greater than or equal to the third determination value Vj3 (S05), and transmits an abnormality determination signal Sa to the main control unit 6 (S06) (see Figure 4). The control device 70 may, for example, determine the abnormality in the sliding shaft support 15 based on the absolute values ​​of the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3. In this case as well, the control device 70 can accurately determine the abnormality in the sliding shaft support 15. In this case, the determination unit 75a may or may not determine the first determination value Vj1, the second determination value Vj2, and the third determination value Vj3.

[0087] The timing at which the control device 70 transmits the abnormality determination signal Sa to the main control unit 6 can be varied, as follows. For example, as shown in Figure 5, the control device 70 may start calculating the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 at time T4, and even if the first fluctuation value Vf1 becomes equal to or greater than the first determination value Vj1 at time Tj, it may transmit the abnormality determination signal Sa to the main control unit 6 at time T5, which is the timing after the first predetermined period P1 has elapsed from time T4. Alternatively, as shown in Figure 6, the control device 70 may start calculating the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 at time T4, and immediately transmit the abnormality determination signal Sa to the main control unit 6 when the second fluctuation value Vf2 becomes equal to or greater than the second determination value Vj2 at time Tj. Similarly, in Figure 7, the control device 70 starts calculating the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 at time T4, and immediately transmits an abnormality determination signal Sa to the main control unit 6 when the third fluctuation value Vf3 becomes equal to or greater than the third determination value Vj3 at time Tj.

[0088] When the control device 70 transmits an abnormality detection signal Sa to the main control unit 6, as described above, the main control unit 6 transmits a rotation time command signal CS2 to the control unit 75. Based on the rotation time command signal CS2, the control unit 75 determines an abnormality in the sliding shaft support unit 15 and calculates a second predetermined period P2 for stopping the operation of the motor unit 20. Various forms can be adopted for the rotation time command signal CS2 that the main control unit 6 inputs to the control device 70, as follows. For example, the rotation time command signal CS2 may be a command signal that immediately stops the operation of the motor unit 20, that is, a command signal in which the second predetermined period P2 is 0 seconds. In this case, as shown in Figure 5, when the control device 70 receives the rotation time command signal CS2 at time T5, it quickly stops the supply of current to the motor unit 20 and stops the operation of the motor unit 20 (S07). Similarly, if the rotation time command signal CS2 is a command signal in which the second predetermined period P2 is 0 seconds, as shown in Figure 6, when the control device 70 receives the rotation time command signal CS2 at time Tj, it quickly stops supplying current to the motor unit 20 and stops the operation of the motor unit 20 (S07). In these cases, since the control device 70 can quickly stop the operation of the motor unit 20 when it determines that there is an abnormality in the sliding shaft support unit 15, it is possible to effectively suppress the rotation of the shaft 23 when the amount of fluid MR interposed between the shaft 23 and the sliding shaft support unit 15 is small. This effectively suppresses the failure of the electric pump 1.

[0089] Furthermore, the rotation time command signal CS2 may be a command signal that stops the operation of the motor unit 20 after the control device 70 has determined an abnormality in the sliding shaft support unit 15 and has continued the operation of the motor unit 20 for a second predetermined period P2. In this case, as shown in Figure 7, when the control device 70 receives the rotation time command signal CS2 at time Tj, it stops the operation of the motor unit 20 at time T6, after the second predetermined period P2 has elapsed from time Tj (S07). That is, the control device 70 stops the operation of the motor unit 20 after the second predetermined period P2 has elapsed after determining an abnormality in the sliding shaft support unit 15 at time Tj. This allows the motor unit 20 to stop operating after supplying the required amount of fluid R to the equipment 5 to be mounted. This suppresses instability in the operation of the equipment 5 to be mounted.

[0090] Furthermore, as shown in Figure 7, the control device 70 may set the rotational speed Rv of the shaft 23 during the second predetermined period P2 to a slower rotational speed. That is, if the control device 70 detects an abnormality in the sliding shaft support 15, it may reduce the rotational speed Rv of the shaft 23. This reduces the frictional force between the shaft 23 and the sliding shaft support 15 during the second predetermined period P2, thereby effectively suppressing failure of the electric pump 1 during the second predetermined period P2.

[0091] If the motor unit 20 stops operating after detecting an abnormality in the sliding shaft support 15, the worker performing maintenance on the electric pump 1 can restore the amount of fluid R supplied from the pump unit 40 to the sliding shaft support 15 to a normal level by performing tasks such as removing foreign matter clogged in the first communication groove 15c (see Figure 1). This allows the amount of fluid MR interposed between the shaft 23 and the sliding shaft support 15 to be set to an appropriate level during the operation of the electric pump 1, thereby reducing the frictional force between the shaft 23 and the sliding shaft support 15. This helps to prevent the electric pump 1 from failing.

[0092] According to this embodiment, the electric pump 1 comprises a motor unit 20 having a shaft 23 that can rotate about a rotation axis J, a pump unit 40 connected to one axial end of the shaft 23 and driven by the power of the motor unit 20 to pump fluid R, a housing 10 housing the motor unit 20 and the pump unit 40, and a control device 70 that controls the operation of the motor unit 20. The housing 10 has a motor housing 10a that houses the motor unit 20, a pump housing 10c that houses the pump unit 40, and a sliding shaft support 15 that supports the shaft 23. A fluid R is interposed between the shaft 23 and the sliding shaft support 15. The control device 70 determines an abnormality due to a deficiency of fluid R in the sliding shaft support 15 based on a first fluctuation value Vf1, which is the fluctuation value of the rotational speed Rv of the shaft 23, a second fluctuation value Vf2, which is the fluctuation value of the current supplied to the motor unit 20, or a third fluctuation value Vf3, which is the fluctuation value of the voltage applied to the control device 70, during a first predetermined period P1 in which the target rotational speed TRv of the shaft 23 is constant. As described above, when the fluid quantity MR, which is the amount of fluid R interposed between the shaft 23 and the sliding shaft support 15, decreases, the frictional force between the shaft 23 and the sliding shaft support 15 increases, causing the rotational speed Rv of the shaft 23 to become unstable. As a result, when the fluid quantity MR decreases, the first fluctuation value Vf1 increases. Furthermore, as described above, the control device 70 controls the current supplied to the motor unit 20 so that the rotational speed Rv of the shaft 23 matches the target rotational speed TRv. Therefore, if the rotational speed Rv of the shaft 23 becomes unstable, the second fluctuation value Vf2 and the third fluctuation value Vf3 will each increase. Based on these, the control device 70 can determine that an abnormality has occurred in the sliding shaft support unit 15 based on the first fluctuation value Vf1, the second fluctuation value Vf2, or the third fluctuation value Vf3. In addition, since the control device 70 can quickly stop the operation of the motor unit 20 when an abnormality occurs in the sliding shaft support unit 15, it is possible to effectively prevent the electric pump 1 from failing.

[0093] According to this embodiment, the control device 70 has a determination unit 75a that determines a first determination value Vj1, a second determination value Vj2, and a third determination value Vj3 based on the target rotational speed TRv. The control device 70 determines an abnormality due to a deficiency of fluid R in the sliding shaft support 15 if the first fluctuation value Vf1 is greater than or equal to the first determination value Vj1, the second fluctuation value Vf2 is greater than or equal to the second determination value Vj2, or the third fluctuation value Vf3 is greater than or equal to the third determination value Vj3. As described above, each of the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 correlates with the rotational speed Rv of the shaft 23, i.e., the target rotational speed TRv. Therefore, by determining the first determination value Vj1, the second determination value Vj2, and the third determination value Vj3 based on the target rotational speed TRv, the control device 70 can accurately determine an abnormality in the sliding shaft support 15 regardless of the target rotational speed TRv. As a result, the control device 70 can quickly stop the operation of the motor unit 20 if an abnormality occurs in the sliding shaft support unit 15, thereby more effectively preventing the electric pump 1 from failing.

[0094] According to this embodiment, the control device 70 detects an abnormality in the sliding shaft support 15 and then stops the operation of the motor unit 20 after a second predetermined period P2 has elapsed. Therefore, as described above, the motor unit 20 can be stopped after supplying the required amount of fluid R to the device 5. This effectively prevents the operation of the device 5 from becoming unstable.

[0095] According to this embodiment, when the control device 70 detects an abnormality in the sliding shaft support 15, it reduces the rotational speed of the shaft 23. Therefore, as described above, the frictional force between the shaft 23 and the sliding shaft support 15 can be reduced during the second predetermined period P2, and thus the failure of the electric pump 1 during the second predetermined period P2 can be effectively suppressed.

[0096] When the electric pump 1 starts operating after being stopped for a long period of time, the fluid volume MR, which is the amount of fluid R interposed between the shaft 23 and the sliding shaft support 15, may decrease. In this case, even if the control device 70 detects an abnormality in the sliding shaft support 15, the pump unit 40 can be driven by rotating the shaft 23 at a low speed during the second predetermined period P2. Therefore, during the second predetermined period P2, the pump unit 40 can supply fluid to the sliding shaft support 15. This allows the shaft 23 to be rotated at a low speed when the fluid volume MR is low, and after the fluid volume MR increases and the rotational speed Rv stabilizes, the rotational speed Rv of the shaft 23 can be increased to the target rotational speed TRv based on the rotational speed command signal CS1.

[0097] According to this embodiment, the pump unit 40 supplies fluid R to the sliding shaft support unit 15. Therefore, in this embodiment, no additional mechanism is required to supply fluid R to the sliding shaft support unit 15, thus preventing an increase in the number of parts of the electric pump 1. Consequently, an increase in the manufacturing cost and manufacturing man-hours of the electric pump 1 can be prevented.

[0098] In this embodiment, the fluid R is oil. Therefore, compared to the case where the fluid R is water, the fluid R can improve the lubrication between the shaft 23 and the sliding shaft support 15. This makes it easier to reduce the frictional force between the shaft 23 and the sliding shaft support 15, and thus makes it easier to suppress wear on both the shaft 23 and the sliding shaft support 15 during the operation of the electric pump 1. Therefore, the lifespan of the electric pump 1 can be effectively extended.

[0099] The control device 70 determines an abnormality in the sliding shaft support section 15 due to a deficiency of fluid R, based on a first fluctuation value Vf1, which is the fluctuation value of the rotational speed Rv of the shaft 23, a second fluctuation value Vf2, which is the fluctuation value of the current supplied to the motor section 20, or a third fluctuation value Vf3, which is the fluctuation value of the voltage applied to the control device 70, during a first predetermined period P1 in which the target rotational speed TRv of the shaft 23 is constant. Therefore, as described above, the control device 70 can determine that an abnormality has occurred in the sliding shaft support section 15 based on the first fluctuation value Vf1, the second fluctuation value Vf2, or the third fluctuation value Vf3. Furthermore, since the control device 70 can quickly stop the operation of the motor section 20 when an abnormality occurs in the sliding shaft support section 15, it can effectively prevent the electric pump 1 from failing.

[0100] <Modified form of the first embodiment> As shown in Figure 9, the electric pump 101 of this modified example has a sliding bearing member 116. In the following description, components that are the same as those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted.

[0101] The modified housing 110 has a housing body 111, a lid 17, a pump cover 19, a motor housing 10a, and a pump housing 10c. The housing body 111 of this modified housing has a cylindrical portion 12, an annular wall portion 13, and a sliding shaft support portion 115. In other words, the housing 110 has a sliding shaft support portion 115.

[0102] The sliding shaft support portion 115 is substantially cylindrical in shape and extends axially with respect to the rotation axis J. A shaft 23 is passed through the interior of the sliding shaft support portion 115 in the axial direction. In this modified example, the sliding shaft support portion 115 is provided with a hole portion 115e. The hole portion 115e is a hole that is recessed in one axial direction from the surface of the sliding shaft support portion 115 facing the other axial side. Viewed from the axial direction, the hole portion 115e is substantially circular in shape with respect to the rotation axis J. In this modified example, the sliding shaft support portion 115 has a sliding bearing member 116.

[0103] The sliding bearing member 116 is substantially annular in shape with respect to the axis of rotation J. In this modified example, the sliding bearing member 116 is a sintered bearing made of a porous metal body manufactured by powder metallurgy and impregnated with lubricating oil. The sliding bearing member 116 may also be made of resin. The sliding bearing member 116 is located inside the hole 115e. The sliding bearing member 116 is fixed to the inner circumferential surface of the hole 115e. The shaft 23 passes through the sliding bearing member 116 in the axial direction. The inner circumferential surface of the sliding bearing member 116 is in contact with the outer circumferential surface of the shaft 23. The sliding bearing member 116 supports the shaft 23 so that it can rotate about the axis of rotation J. As a result, the sliding shaft support portion 115 functions as a sliding bearing that supports the shaft 23. In this modified example, the pump portion 40 supplies fluid R between the shaft 23 and the inner circumferential surface of the sliding bearing member 116. That is, the pump portion 40 supplies fluid R between the shaft 23 and the sliding shaft support portion 115. This allows for the suitable interposition of fluid R between the shaft 23 and the sliding shaft support portion 115, similar to the first embodiment described above. Therefore, the fluid R can suitably lubricate the shaft 23 and the sliding shaft support portion 115. Other configurations of the housing 110 in this modified example are the same as those of the housing 10 in the first embodiment described above. Other configurations of the electric pump 101 in this modified example are the same as those of the electric pump 1 in the first embodiment described above.

[0104] The method for determining abnormalities in the sliding shaft support portion 115 in this modified example is the same as the method for determining abnormalities in the sliding shaft support portion 15 in the first embodiment described above. In this modified example, when the fluid amount MR, which is the amount of fluid R interposed between the shaft 23 and the sliding bearing member 116, decreases, the shaft 23 and the sliding bearing member 116 become more likely to come into direct contact. As a result, the frictional force between the shaft 23 and the sliding bearing member 116 increases. Therefore, as in the first embodiment described above, when the fluid amount MR decreases, the rotational speed Rv of the shaft 23 becomes unstable. As a result, when the fluid amount MR decreases, the first fluctuation value Vf1, the second fluctuation value Vf2, and the third fluctuation value Vf3 each increase. Therefore, as in the first embodiment described above, the control device 70 can determine that an abnormality has occurred in the sliding shaft support portion 115 based on the first fluctuation value Vf1, the second fluctuation value Vf2, or the third fluctuation value Vf3. Therefore, if an abnormality occurs in the sliding shaft support section 115, the control device 70 can quickly stop the operation of the motor section 20, thereby effectively preventing the electric pump 101 from failing.

[0105] According to this modified example, the sliding shaft support portion 115 has a sliding bearing member 116 that supports the shaft 23. Therefore, even if the amount of wear on the sliding bearing member 116 increases due to a decrease in the amount of fluid R interposed between the shaft 23 and the sliding bearing member 116, the electric pump 101 can be restored by replacing only the sliding bearing member 116. Thus, the maintainability of the electric pump 101 can be improved.

[0106] <Second Embodiment> Figure 10 is a flowchart showing the method for determining abnormalities in the electric pump 201 of this embodiment. In this embodiment, the control device 270 determines that there is an abnormality due to a deficiency of fluid R in the sliding shaft support 15 when the rotational speed Rv of the shaft 23 is equal to or greater than the first determination speed Rj1, or when the rotational speed Rv of the shaft 23 is equal to or less than the second determination speed Rj2. In the following description, components that are the same as those in the first embodiment described above are denoted by the same reference numerals, and their descriptions are omitted.

[0107] Although not shown in the figures, the electric pump 201 of this embodiment comprises a housing 10, a motor unit 20, a pump unit 40, and a control device 270. Although not shown in the figures, the control device 270 includes a circuit board 71, a motor drive circuit 72, a control unit 75, a storage unit 76, and a first detection unit 77. Similar to the first embodiment described above, the first detection unit 77 detects the voltage applied to the coils 33U, 33V, and 33W of each phase and inputs the detection result to the control unit 75. The control unit 75 calculates the rotational speed Rv of the shaft 23 based on the back electromotive force generated in the U-phase coil 33U, V-phase coil 33V, and W-phase coil 33W that are not supplied with current from the motor drive circuit 72. Also, similar to the first embodiment described above, the control device 270 controls the current supplied to the motor unit 20 so that the rotational speed Rv of the shaft 23 matches the target rotational speed TRv.

[0108] Figure 11 is the first diagram showing an example of the rotational speed Rv of the shaft 23 in the electric pump 201 of this embodiment. The upper graph of Figure 11 shows the change in the fluid amount MR, which is the amount of fluid R interposed between the shaft 23 and the sliding shaft support portion 15. In this embodiment, we will describe the case in which the fluid amount MR stabilizes at a sufficient amount from time T0 to time T3, and then monotonically decreases after time T3. Similar to the first embodiment described above, as the fluid amount MR decreases, the shaft 23 and the support surface 15a are more likely to come into direct contact, so the frictional force between the shaft 23 and the sliding shaft support portion 15 increases.

[0109] The lower graph in Figure 11 shows the change in the rotational speed Rv of the shaft 23 calculated by the control unit 75. The rotational speed Rv oscillates around the target rotational speed TRv. From time T0 to time T3, when the fluid volume MR is stable at a sufficient amount, the fluid R can suitably lubricate the shaft 23 and the sliding shaft support 15, thereby reducing the frictional force between the shaft 23 and the sliding shaft support 15. As a result, the rotational speed Rv is stable, and the amplitude of the rotational speed Rv is small. In contrast, from time T3 onward, when the fluid volume MR decreases, the frictional force between the shaft 23 and the sliding shaft support 15 increases, as described above. As a result, from time T3 onward, the rotational speed Rv becomes unstable, and the amplitude of the rotational speed Rv increases. In other words, as the fluid volume MR decreases, the maximum rotational speed of the shaft 23 increases, and the minimum rotational speed of the shaft 23 decreases. Therefore, the control device 270 can determine an abnormality in the sliding shaft support 15 based on the maximum or minimum rotational speed of the shaft 23. Furthermore, the maximum and minimum rotational speeds of shaft 23 are correlated with the target rotational speed TRv.

[0110] Similar to the first embodiment described above, the control device 270 has a determination unit 75a. In this embodiment, the determination unit 75a determines a first determination speed Rj1 and a second determination speed Rj2 based on the target rotational speed TRv. The first determination speed Rj1 and the second determination speed Rj2 are threshold values ​​of the rotational speed Rv for the control device 270 to determine an abnormality in the sliding shaft support unit 15. As shown in Figure 11, the first determination speed Rj1 is a rotational speed faster than the target rotational speed TRv. The second determination speed Rj2 is a rotational speed slower than the target rotational speed TRv. The first determination speed Rj1 and the second determination speed Rj2 are appropriately determined based on the set target rotational speed TRv and the amplitude of the rotational speed Rv when the fluid volume MR decreases at the target rotational speed TRv, which has been measured in advance. In this embodiment, the control device 270 determines that no abnormality has occurred in the sliding shaft support 15 when the rotational speed Rv of the shaft 23 is less than the first determination speed Rj1 and faster than the second determination speed Rj2, and continues to operate the motor unit 20. Conversely, as shown in Figure 11, the control device 270 determines that an abnormality has occurred in the sliding shaft support 15 due to a deficiency of fluid R when the rotational speed Rv of the shaft 23 becomes equal to or greater than the first determination speed Rj1. Also, as shown in Figure 12, the control device 270 determines that an abnormality has occurred in the sliding shaft support 15 due to a deficiency of fluid R when the rotational speed Rv of the shaft 23 becomes equal to or less than the second determination speed Rj2.

[0111] Figure 10 is a flowchart showing the method for determining abnormalities in the sliding shaft support section 15 according to this embodiment. When the control device 270 starts the operation of the motor section 20, the determination unit 75a determines the first determination speed Rj1 and the second determination speed Rj2 based on the target rotational speed TRv (S11). In this embodiment, each time the target rotational speed TRv is changed, the determination unit 75a determines the first determination speed Rj1 and the second determination speed Rj2 based on the target rotational speed TRv.

[0112] Next, the control device 270 calculates the rotational speed Rv of the shaft 23 (S12). Then, if the rotational speed Rv is less than the first determination speed Rj1 (S13) or greater than the second determination speed Rj2 (S14), the control device 270 determines that there is no shortage of fluid volume MR and continues the operation of the motor unit 20. From here on, the control device 270 repeats the above operation. In contrast, as shown in Figure 11, when the rotational speed Rv becomes greater than or equal to the first determination speed Rj1 (S13), or as shown in Figure 12, when the rotational speed Rv becomes less than or equal to the second determination speed Rj2 (S14), the control device 270 determines that there is an abnormality in the sliding shaft support unit 15 and transmits an abnormality determination signal Sa to the main unit control unit 6 (S06). When the control device 270 determines that there is an abnormality in the sliding shaft support unit 15 at time Tj, it immediately transmits an abnormality determination signal Sa to the main unit control unit 6.

[0113] When the control device 270 transmits an abnormality determination signal Sa to the main control unit 6, the main control unit 6 transmits a rotation time command signal CS2 to the control unit 75, similar to the first embodiment described above. Based on the rotation time command signal CS2, the control unit 75 determines an abnormality in the sliding shaft support 15 and calculates a second predetermined period P2 for stopping the operation of the motor unit 20. Various forms can be adopted for the rotation time command signal CS2 that the main control unit 6 inputs to the control device 270, as follows. For example, the rotation time command signal CS2 may be a command signal in which the second predetermined period P2 is 0 seconds. In this case, as shown in Figure 11, when the control device 270 receives the rotation time command signal CS2 at time Tj, it quickly stops the supply of current to the motor unit 20 and stops the operation of the motor unit 20 (S07). In this case, the rotation of the shaft 23 while the amount of fluid MR interposed between the shaft 23 and the sliding shaft support 15 is small can be suitably suppressed, and thus the failure of the electric pump 201 can be suitably suppressed.

[0114] Furthermore, the rotation time command signal CS2 may be a command signal that stops the operation of the motor unit 20 after the control device 270 has determined an abnormality in the sliding shaft support unit 15 and has continued the operation of the motor unit 20 for a second predetermined period P2. In this case, as shown in Figure 12, when the control device 270 receives the rotation time command signal CS2 at time Tj, it stops the operation of the motor unit 20 at time T7, after the second predetermined period P2 has elapsed from time Tj (S07). This allows the motor unit 20 to stop operating after supplying the required amount of fluid R to the device 5. This helps to prevent the operation of the device 5 from becoming unstable.

[0115] Furthermore, as shown in Figure 12, the control device 270 may reduce the rotational speed Rv of the shaft 23 during the second predetermined period P2. This reduces the frictional force between the shaft 23 and the sliding shaft support 15 during the second predetermined period P2, thereby effectively suppressing failure of the electric pump 201 during the second predetermined period P2. Other configurations of the control device 270 in this embodiment are the same as those of the control device 70 in the first embodiment described above. Other configurations of the electric pump 201 in this embodiment are the same as those of the electric pump 1 in the first embodiment described above.

[0116] According to this embodiment, the electric pump 201 comprises a motor unit 20, a pump unit 40, a housing 10, and a control device 270 that controls the operation of the motor unit 20. The control device 270 has a determination unit 75a that determines a first determination speed Rj1, which is a rotational speed faster than the target rotational speed TRv of the shaft 23, and a second determination speed Rj2, which is a rotational speed slower than the target rotational speed TRv. When the rotational speed Rv of the shaft 23 becomes greater than or equal to the first determination speed Rj1, or less than or equal to the second determination speed Rj2, the control device 270 determines that there is an abnormality due to a deficiency of fluid R in the sliding shaft support unit 15. As described above, when the amount of fluid MR, which is the amount of fluid R interposed between the shaft 23 and the sliding shaft support unit 15, decreases, the rotational speed Rv becomes unstable, and the amplitude of the rotational speed Rv increases. As a result, the control device 270 can determine that an abnormality has occurred in the sliding shaft support section 15 due to a deficiency of fluid R by determining that the rotational speed Rv is equal to or greater than the first determination speed Rj1, or that the rotational speed Rv is equal to or less than the second determination speed Rj2. Furthermore, since the control device 270 can quickly stop the operation of the motor section 20 when an abnormality occurs in the sliding shaft support section 15, it is possible to effectively prevent the electric pump 201 from failing.

[0117] According to this embodiment, the determination unit 75a determines a first determination speed Rj1 and a second determination speed Rj2 based on the target rotational speed TRv. As described above, the maximum rotational speed and minimum rotational speed of the shaft 23 are correlated with the target rotational speed TRv. Therefore, by determining the first determination speed Rj1 and the second determination speed Rj2 based on the target rotational speed TRv, the control device 270 can accurately determine abnormalities in the sliding shaft support 15 regardless of the target rotational speed TRv. As a result, the control device 270 can quickly stop the operation of the motor unit 20 when an abnormality occurs in the sliding shaft support 15, thereby more effectively preventing the electric pump 201 from failing.

[0118] According to this embodiment, the control device 270 has a determination unit 75a that determines a first determination speed Rj1, which is a rotational speed faster than the target rotational speed TRv of the shaft 23, and a second determination speed Rj2, which is a rotational speed slower than the target rotational speed TRv. When the rotational speed Rv of the shaft 23 becomes equal to or greater than the first determination speed Rj1, or equal to or less than the second determination speed Rj2, the control device 270 determines that there is an abnormality due to a shortage of fluid R in the sliding shaft support 15. Therefore, as described above, the control device 270 can determine that an abnormality due to a shortage of fluid R in the sliding shaft support 15 has occurred by determining that the rotational speed Rv is equal to or greater than the first determination speed Rj1, or equal to or less than the second determination speed Rj2. In addition, since the control device 270 can quickly stop the operation of the motor unit 20 when an abnormality occurs in the sliding shaft support 15, it is possible to suitably prevent the electric pump 201 from failing.

[0119] Although embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are merely examples, and additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited by the embodiments.

[0120] The control device does not need to be housed inside the housing; it may be located outside the housing. Furthermore, the control device may calculate the rotational speed of the rotor core, i.e., the rotational speed of the shaft, based on the detection results of a sensor such as a Hall element that detects the magnetic field formed by the magnets of the rotor. The control device may also determine abnormalities due to insufficient fluid in the sliding shaft support based on the rotational speed of the rotor core.

[0121] Furthermore, the configuration of the fluid path in the electric pump is merely an example, and as long as the fluid can be pumped to the outside of the electric pump and the fluid can be supplied between the shaft and the sliding shaft support, the configuration is not limited to the above-described embodiment and its modified form.

[0122] The applications of the electric pump to which the present invention is applied are not particularly limited. The type of fluid delivered by the electric pump is not particularly limited and may be a liquid other than oil, such as water. The electric pump may be mounted on equipment other than vehicles. Furthermore, the configurations described herein can be combined as appropriate, within the bounds of what is not mutually contradictory.

[0123] Furthermore, this technology can be configured as follows: (1) An electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; a housing housing the motor unit and the pump unit; and a control device for controlling the operation of the motor unit, wherein the housing has a motor housing unit for housing the motor unit, a pump housing unit for housing the pump unit, and a sliding shaft support unit for supporting the shaft, the fluid is interposed between the shaft and the sliding shaft support unit, and the control device determines an abnormality due to a shortage of the fluid in the sliding shaft support unit based on a first fluctuation value which is the fluctuation value of the rotation speed of the shaft, a second fluctuation value which is the fluctuation value of the current supplied to the motor unit, or a third fluctuation value which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotation speed of the shaft is constant, (2) The electric pump according to (1), wherein the control device has a determination unit that determines a first determination value, a second determination value, and a third determination value based on the target rotational speed, and the control device determines an abnormality due to a shortage of fluid in the sliding shaft support when the first fluctuation value is equal to or greater than the first determination value, when the second fluctuation value is equal to or greater than the second determination value, or when the third fluctuation value is equal to or greater than the third determination value. (3) An electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; a housing housing the motor unit and the pump unit; and a control device for controlling the operation of the motor unit, wherein the housing has a motor housing unit for housing the motor unit, a pump housing unit for housing the pump unit, and a sliding shaft support unit for supporting the shaft, the fluid is interposed between the shaft and the sliding shaft support unit, and the control device has a determination unit for determining a first determination speed which is a rotation speed faster than the target rotation speed of the shaft, and a second determination speed which is a rotation speed slower than the target rotation speed, and when the rotation speed of the shaft is equal to or greater than the first determination speed, or when the rotation speed of the shaft is less than or equal to the second determination speed, it determines an abnormality due to a shortage of fluid in the sliding shaft support unit. (4) The electric pump according to (3), wherein the determination unit determines the first determination speed and the second determination speed based on the target rotational speed. (5) The electric pump according to any one of (1) to (4), wherein the control device stops the operation of the motor section after a second predetermined period has elapsed since determining the abnormality. (6) The electric pump according to any one of (1) to (4), wherein the control device reduces the rotational speed of the shaft when it detects the abnormality. (7) The pump section is an electric pump according to any one of (1) to (6) that supplies the fluid to the sliding shaft support section. (8) The electric pump according to any one of (1) to (7), wherein the fluid is oil. (9) The electric pump according to any one of (1) to (8), wherein the sliding shaft support portion has a sliding bearing member that supports the shaft. (10) A control device for controlling the operation of an electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; and a housing housing the motor unit and the pump unit, wherein the housing has a motor housing unit housing the motor unit, a pump housing unit housing the pump unit, and a sliding shaft support unit supporting the shaft, the fluid is interposed between the shaft and the sliding shaft support unit, and the control device determines an abnormality due to a shortage of the fluid in the sliding shaft support unit based on a first fluctuation value which is a fluctuation value of the rotation speed of the shaft, a second fluctuation value which is a fluctuation value of the current supplied to the motor unit, or a third fluctuation value which is a fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotation speed of the shaft is constant. (11) A control device for controlling the operation of an electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; and a housing housing the motor unit and the pump unit, the control device having a determination unit that determines a first determination speed which is a rotation speed faster than the target rotation speed of the shaft, and a second determination speed which is a rotation speed slower than the target rotation speed, wherein the housing has a motor housing unit for housing the motor unit, a pump housing unit for housing the pump unit, and a sliding shaft support unit for supporting the shaft, the fluid is interposed between the shaft and the sliding shaft support unit, and the control device determines an abnormality due to a shortage of the fluid in the sliding shaft support unit when the rotation speed of the shaft is equal to or greater than the first determination speed, or when the rotation speed of the shaft is equal to or less than the second determination speed. [Explanation of Symbols]

[0124] 1,101,201…Electric pump, 10,110…Housing, 10a…Motor housing, 10c…Pump housing, 15,115…Sliding shaft support, 20…Motor section, 23…Shaft, 40…Pump section, 70,270…Control device, 75a…Determination section, 116…Sliding bearing member, J…Rotation axis, P1…First predetermined period, P2…Second predetermined period, R…Fluid, Rj1…First determination speed, Rj2…Second determination speed, Rv…Shaft rotation speed, TRv…Target shaft rotation speed, Vf1…First fluctuation value, Vf2…Second fluctuation value, Vf3…Third fluctuation value, Vj1…First determination value, Vj2…Second determination value, Vj3…Third determination value

Claims

1. A motor unit having a shaft that can rotate around a rotation axis, A pump unit is connected to one end of the shaft on the axial side and is driven by the power of the motor unit to pump fluid, A housing that houses the motor unit and the pump unit, A control device for controlling the operation of the motor unit, Equipped with, The housing has a motor housing for housing the motor unit, a pump housing for housing the pump unit, and a sliding shaft support for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support portion. The control device determines an abnormality in the sliding shaft support section due to a lack of fluid based on a first fluctuation value, which is the fluctuation value of the rotational speed of the shaft, a second fluctuation value, which is the fluctuation value of the current supplied to the motor section, or a third fluctuation value, which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotational speed of the shaft is constant.

2. The control device has a determination unit that determines a first determination value, a second determination value, and a third determination value based on the target rotational speed. The electric pump according to claim 1, wherein the control device determines an abnormality due to a shortage of fluid in the sliding shaft support when the first fluctuation value is greater than or equal to the first determination value, the second fluctuation value is greater than or equal to the second determination value, or the third fluctuation value is greater than or equal to the third determination value.

3. A motor unit having a shaft that can rotate around a rotation axis, A pump unit is connected to one end of the shaft on the axial side and is driven by the power of the motor unit to pump fluid, A housing that houses the motor unit and the pump unit, A control device for controlling the operation of the motor unit, Equipped with, The housing has a motor housing for housing the motor unit, a pump housing for housing the pump unit, and a sliding shaft support for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support portion. The control device has a determination unit that determines a first determination speed which is a rotational speed faster than the target rotational speed of the shaft, and a second determination speed which is a rotational speed slower than the target rotational speed, and when the rotational speed of the shaft is equal to or greater than the first determination speed, or when the rotational speed of the shaft is less than or equal to the second determination speed, it determines that there is an abnormality due to a shortage of fluid in the sliding shaft support part, an electric pump.

4. The electric pump according to claim 3, wherein the determination unit determines the first determination speed and the second determination speed based on the target rotation speed.

5. The electric pump according to any one of claims 1 to 4, wherein the control device stops the operation of the motor unit after a second predetermined period has elapsed since determining the abnormality.

6. The electric pump according to any one of claims 1 to 4, wherein the control device reduces the rotational speed of the shaft when it detects the abnormality.

7. The electric pump according to any one of claims 1 to 4, wherein the pump section supplies the fluid to the sliding shaft support section.

8. The electric pump according to any one of claims 1 to 4, wherein the fluid is oil.

9. The electric pump according to any one of claims 1 to 4, wherein the sliding shaft support portion has a sliding bearing member that supports the shaft.

10. A control device for controlling the operation of an electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; and a housing that houses the motor unit and the pump unit, The housing has a motor housing for housing the motor unit, a pump housing for housing the pump unit, and a sliding shaft support for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support portion. A control device that determines an abnormality in the sliding shaft support section due to a deficiency of the fluid, based on a first fluctuation value which is the fluctuation value of the rotational speed of the shaft, a second fluctuation value which is the fluctuation value of the current supplied to the motor section, or a third fluctuation value which is the fluctuation value of the voltage applied to the control device, during a first predetermined period in which the target rotational speed of the shaft is constant.

11. A control device for controlling the operation of an electric pump comprising: a motor unit having a shaft rotatable about a rotation axis; a pump unit connected to one axial end of the shaft and driven by the power of the motor unit to pump fluid; and a housing that houses the motor unit and the pump unit, The system includes a determination unit that determines a first determination speed which is a rotational speed faster than the target rotational speed of the shaft, and a second determination speed which is a rotational speed slower than the target rotational speed. The housing has a motor housing for housing the motor unit, a pump housing for housing the pump unit, and a sliding shaft support for supporting the shaft. The fluid is interposed between the shaft and the sliding shaft support portion. A control device that determines an abnormality due to a shortage of fluid in the sliding shaft support when the rotational speed of the shaft exceeds a first determination speed or falls below a second determination speed.

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