JP7662980B2 - Electric pump - Google Patents

Description

The present invention relates to an electric pump.

There is known a pump mechanism having an inner rotor with external teeth, an outer rotor that surrounds the inner rotor and has internal teeth that mesh with the external teeth of the inner rotor. For example, Patent Document 1 describes a trochoid gear pump as such a pump.

Japanese Utility Model Application Publication No. 06-67876

In the pump described above, a pump housing section that houses the inner rotor and the outer rotor, and an intake section and an exhaust section that are connected to the pump housing section are provided. When fluid flows into the pump housing section from the intake section, there is a problem in that the inner rotor and the outer rotor in the pump housing section tilt due to the pressure of the fluid.

One aspect of the present invention includes a pump mechanism that is rotatable around a central axis extending in the axial direction and has an inner rotor with external teeth, and an outer rotor that surrounds the inner rotor and has internal teeth that mesh with the external teeth, and a pump housing that has a pump housing section that houses the pump mechanism, and an intake section and a discharge section that are connected to the pump housing section. The pump housing has a first end face that faces the pump mechanism in the axial direction on one axial side of the pump mechanism, and a second end face that faces the pump mechanism in the axial direction on the other axial side of the pump mechanism and axially sandwiches the pump mechanism between the first end face. The intake section has a first intake side recess that is recessed from the first end face to one axial side, and a second intake side recess that is recessed from the second end face to the other axial side. The discharge section has a first discharge side recess that is recessed from the first end face to one axial side, and a second discharge side recess that is recessed from the second end face to the other axial side. The bottom surface of the first suction side recess and the bottom surface of the second suction side recess each have a suction side inclined surface that is inclined with respect to a plane that intersects with the axial direction. The bottom surface of the first discharge side recess and the bottom surface of the second discharge side recess each have a discharge side inclined surface that is inclined with respect to a plane that intersects with the axial direction. The suction side inclined surface of the first suction side recess and the suction side inclined surface of the second suction side recess at least partially overlap each other when viewed from the axial direction, and are inclined in a direction that approaches each other in the axial direction toward one side in the circumferential direction around the central axis. The discharge side inclined surface of the first discharge side recess and the discharge side inclined surface of the second discharge side recess at least partially overlap each other when viewed from the axial direction, and are inclined in a direction that moves away from each other in the axial direction toward one side in the circumferential direction.

According to one aspect of the present invention, an electric pump is provided that can suppress vibration of the pump mechanism.

FIG. 1 is a cross-sectional view of the electric pump of this embodiment, taken along line II of FIG. FIG. 2 is a perspective view, including a partial cross section, showing the pump mechanism and the suction side structure of the present embodiment. FIG. 3 is a perspective view showing the pump mechanism and the discharge side structure of the present embodiment, and is a perspective view including a cross section taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing the structure of the pump mechanism and the suction and discharge portions of this embodiment, and includes a cross-sectional view of the pump housing side taken along line IV-IV in FIG. 5 and a cross-sectional view of the pump cover side taken along line VI-VI in FIG. FIG. 5 is a diagram showing the structure of the first suction side recess and the first discharge side recess on the pump housing side. FIG. 6 is a view showing the inner surface side of the pump cover. FIG. 7 is a diagram showing the positional relationship between the pump mechanism and the suction portion and discharge portion of the pump housing.

In each of the drawings referred to below, an XYZ coordinate system is shown as a three-dimensional orthogonal coordinate system as appropriate.
In the XYZ coordinate system, the X-axis direction is parallel to the axis of the central axis J shown in Fig. 1. The central axis J is the central axis of a shaft 21 of a motor 220, which will be described later. The Y-axis direction is a direction perpendicular to the X-axis, parallel to the up-down direction in Fig. 1. The Z-axis direction is a direction perpendicular to both the X-axis and Y-axis directions, and parallel to the depth direction in Fig. 1. In each of the X-axis, Y-axis, and Z-axis directions, the side toward which the arrow in the figure points is the + side, and the opposite side is the - side.

In the following description, unless otherwise specified, the direction parallel to the central axis J (X-axis direction) is simply referred to as the "axial direction." The radial direction centered on the central axis J is simply referred to as the "radial direction." The circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, is simply referred to as the "circumferential direction." The side of the circumferential direction that progresses clockwise when viewed from the +X side is referred to as "one side of the circumferential direction." The side of the circumferential direction that progresses counterclockwise when viewed from the +X side is referred to as "the other side of the circumferential direction."

In this embodiment, the "one side in the circumferential direction" may simply be referred to as the "downstream side" in the direction in which oil flows in the electric pump 200. The "other side in the circumferential direction" may simply be referred to as the "upstream side" in the direction in which oil flows in the electric pump 200.

The positive side (+X side) in the X-axis direction may be referred to as the "front side." Similarly, the negative side (-X side) in the X-axis direction may be referred to as the "rear side." The rear side (-X side) corresponds to one axial side in this invention. The front side (+X side) corresponds to the other axial side in this invention.

The electric pump 200 of this embodiment is an electric oil pump that pumps oil as a fluid. The electric pump 200 is used, for example, to supply oil to equipment mounted on a vehicle or the like. As shown in Figures 1 and 2, the electric pump 200 includes a pump housing 210, a motor 220, and a pump mechanism 30.

The pump housing 210 has a housing body 211, a pump cover 212, and a motor cover 213. The housing body 211 has a motor housing section 211a that houses the motor 220, a pump housing section 211b that houses the pump mechanism 30, and a first through hole 211c that connects the inside of the motor housing section 211a to the inside of the pump housing section 211b.

The motor housing 211a is provided in the rear side (-X side) of the housing body 211. The motor housing 211a is cylindrical and opens to the rear side and extends in the axial direction. The rear side opening of the motor housing 211a is closed from the rear side by the motor cover 213. The motor 220 housed in the motor housing 211a has a rotor 22 having a shaft 21, a stator 23 located radially outside the rotor 22, a bus bar assembly 224, a bus bar cover 225, a first bearing 27, and a second bearing 28. In this embodiment, the first bearing 27 and the second bearing 28 are rolling bearings. Either or both of the first bearing 27 and the second bearing 28 may be a sliding bearing. The front end of the shaft 21 is connected to the pump mechanism 30.

As shown in FIG. 1, the busbar assembly 224 has a plurality of busbars 224a and a resin busbar holder 224b that holds the plurality of busbars 224a. The busbar assembly 224 has a circular ring shape when viewed from the axial direction. The plurality of busbars 224a are held with portions embedded in the busbar holder 224b.

The bus bar assembly 224 is located on the rear side of the stator 23. The bus bar assembly 224 is inserted into the motor accommodating portion 211a from the rear side.
One end of the bus bar 224a is connected to a coil wire 23d extending from the coil 23c of the stator 23 toward the rear side.

The busbar cover 225 is located on the rear side of the busbar assembly 224. The busbar cover 225 is inserted into the motor housing section 211a from the rear side. Although not shown in the figure, the busbar cover 225 has a circular ring shape when viewed from the axial direction. The busbar cover 225 covers the busbar assembly 224 from the rear side. The motor cover 213 is placed over the rear side of the busbar cover 225.

The motor cover 213 is a disk-shaped member that covers the bus bar cover 225 from the rear side. The motor cover 213 has a cylindrical portion 213a extending along the central axis J and an annular cover body 213b that extends radially outward from the outer circumferential surface of the cylindrical portion 213a. Although not shown, the cylindrical portion 213a opens on both sides in the axial direction of the motor cover 213. As shown in FIG. 2, the front opening of the cylindrical portion 213a is a bearing holding portion 213c that holds the first bearing 27. As shown in FIG. 3, a breather 60 is attached to the rear opening of the cylindrical portion 213a. Although not shown, the breather 60 has a built-in filter. The filter of the breather 60 is, for example, a gas-liquid separation filter that allows gas to pass but blocks liquid.

The cover body 213b extends radially outward from the busbar cover 225. The cover body 213b is screwed to the housing body 211 at a location radially outward from the busbar cover 225.

As shown in FIG. 2, the second bearing 28 is inserted into the first through hole 211c from the rear side. Inside the first through hole 211c, the oil seal 15, the fixing ring 16, the wave washer 17, and the second bearing 28 are arranged in this order from the front side.

The shaft 21 passes through the inner holes of the second bearing 28, the wave washer 17, the fixing ring 16, and the oil seal 15. The pump mechanism 30 is connected to the front end of the shaft 21.

The pump housing 211b is located on the front side (+X side) of the motor housing 211a. The pump housing 211b is configured by a recess that opens to the front side. The pump housing 211b is, for example, a circular recess when viewed from the front side. The front opening of the pump housing 211b is closed from the front side by a pump cover 212. The pump mechanism 30 housed in the pump housing 211b has an inner rotor 31 connected to the front end of the shaft 21, and an outer rotor 32 located radially outside the inner rotor 31.

The pump mechanism 30 of this embodiment is, for example, a trochoid pump. The inner rotor 31 and the outer rotor 32 mesh with each other. The inner rotor 31, which has external teeth, and the outer rotor 32, which has internal teeth 32a that mesh with the external teeth 31a of the inner rotor 31, are pump gears. The inner rotor 31 and the outer rotor 32 each have a trochoid tooth profile. The inner rotor 31 is connected to the shaft 21 of the motor 220. The inner rotor 31 is rotated by the rotation of the shaft 21 around the central axis J. The rotation of the inner rotor 31 also rotates the outer rotor 32 that meshes with the inner rotor 31. In this way, the motor 220 rotates the inner rotor 31 to drive the pump mechanism 30. The rotation axis of the outer rotor 32 is an axis that is radially eccentric with respect to the central axis J.

The pump cover 212 is fixed to the front side of the housing body 211. The pump cover 212 extends radially outward from the pump accommodating portion 211b. The pump cover 212 is fastened to the housing side connecting end surface 211d facing the front side of the housing body 211 at a position radially outward from the pump accommodating portion 211b using a plurality of screws 215 shown in FIG. 1. An annular seal member 214 is disposed on the housing side connecting end surface 211d, surrounding the opening of the pump accommodating portion 211b from the radial outside. The seal member 214 seals between the housing body 211 and the pump cover 212.

As shown in FIG. 4, the pump housing 210 has a first end face 210a, a second end face 210b, an intake section 61 and an exhaust section 62 connected to the pump housing section 211b, and an intake side flow path 81 and an exhaust side flow path 82. The first end face 210a is provided on the housing body 211. The first end face 210a is a surface located on the rear side of the inner surface of the pump housing section 211b. The first end face 210a faces the front side. The first end face 210a faces the pump mechanism 30 in the axial direction on the rear side of the pump mechanism 30. The first end face 210a is, for example, a flat surface perpendicular to the axial direction.

The second end surface 210b is provided on the pump cover 212. The second end surface 210b is a portion of the rear surface of the pump cover 212 that faces the pump mechanism 30. The second end surface 210b faces the rear side. The second end surface 210b faces the pump mechanism 30 in the axial direction on the front side of the pump mechanism 30. The second end surface 210b sandwiches the pump mechanism 30 in the axial direction between the second end surface 210b and the first end surface 210a. The second end surface 210b closes the opening on the front side of the pump housing portion 211b. The second end surface 210b is, for example, a flat surface perpendicular to the axial direction.

As shown in FIG. 2, the suction section 61 is connected to the suction port 51 provided on the side of the pump housing 210 via the suction side flow path 81. The suction port 51 is located, for example, closer to the motor 220 than the pump accommodating section 211b. Oil that flows from the suction port 51 into the suction side flow path 81 flows into the suction section 61. As shown in FIG. 2 and FIG. 4, the suction section 61 has a first suction side recess 71 located on the housing body 211 side with respect to the pump accommodating section 211b, and a second suction side recess 91 located on the pump cover 212 side with respect to the pump accommodating section 211b. The shape of the first suction side recess 71 as viewed from the axial direction and the shape of the second suction side recess 91 as viewed from the axial direction are, for example, the same shape as each other. The first suction side recess 71 and the second suction side recess 91 at least partially overlap each other as viewed from the axial direction. The first suction side recess 71 and the second suction side recess 91, for example, entirely overlap each other as viewed from the axial direction.

3, the discharge section 62 is connected to the discharge port 52 provided on the side of the pump housing 210 via the discharge side flow path 82. The discharge port 52 is located, for example, closer to the motor 220 than the pump accommodating section 211b. Oil discharged from the pump mechanism 30 flows into the discharge section 62. As shown in FIGS. 3 and 4, the discharge section 62 has a first discharge side recess 72 located on the housing body 211 side with respect to the pump accommodating section 211b, and a second discharge side recess 92 located on the pump cover 212 side with respect to the pump accommodating section 211b. The shape of the first discharge side recess 72 as viewed from the axial direction and the shape of the second discharge side recess 92 as viewed from the axial direction are, for example, the same shape. The first discharge side recess 72 and the second discharge side recess 92 at least partially overlap each other as viewed from the axial direction. The first discharge side recess 72 and the second discharge side recess 92 overlap each other entirely as viewed from the axial direction, for example.

As shown in FIG. 4, the first suction side recess 71 and the first discharge side recess 72 are recessed from the first end face 210a toward the rear side. The first suction side recess 71 and the first discharge side recess 72 are, for example, disposed at the same position in the axial direction. The axial depth T1 of the first suction side recess 71 and the axial depth T2 of the first discharge side recess 72 are, for example, the same. Note that the depth T1 and the depth T2 may be different from each other.

As shown in FIG. 5, the first suction side recess 71 and the first discharge side recess 72 are, for example, grooves extending in the circumferential direction. In this embodiment, when viewed in the axial direction, the first suction side recess 71 and the first discharge side recess 72 extend in an arc shape along the circumferential direction around the central axis J.

As shown in FIG. 7, the radial outer edge of the first suction side recess 71 and the radial outer edge of the first discharge side recess 72 extend in an arc shape in a direction along the outer circumference of the outer rotor 32 of the pump mechanism 30, i.e., in the circumferential direction around the rotation axis of the outer rotor 32, when viewed from the axial direction. The radial inner edge of the first suction side recess 71 and the radial inner edge of the first discharge side recess 72 extend in an arc shape in the circumferential direction around the central axis J, when viewed from the axial direction.

When viewed from the axial direction, the side surface 71a of the first suction side recess 71 facing radially inward and the side surface 72a of the first discharge side recess 72 facing radially inward overlap in the axial direction with a number of maximum diameter portions 32c of the inner circumferential surface 32b facing radially inward of the outer rotor 32 of the pump mechanism 30.

As shown by the thick arrows in FIG. 5, in the first suction side recess 71 and the first discharge side recess 72, oil flows from the other circumferential side to one circumferential side. In other words, in the first suction side recess 71 and the first discharge side recess 72, the other circumferential side, i.e., the side opposite to the side indicated by the thick arrow in FIG. 5, is the upstream side, and the one circumferential side, i.e., the side indicated by the thick arrow in FIG. 5, is the downstream side.

In this embodiment, the first suction side recess 71 gradually widens in radial width from the upstream end 71h to the downstream end 71j in the circumferential direction around the central axis J. The upstream end 71h is the end of the first suction side recess 71 on the other circumferential side. The downstream end 71j is the end of the first suction side recess 71 on one circumferential side. In other words, the radial width of the first suction side recess 71 increases from the other circumferential side to one circumferential side.

Meanwhile, the radial width of the first discharge side recess 72 gradually narrows from the upstream end 72h to the downstream end 72j in the circumferential direction around the central axis J. The upstream end 72h is the end of the first discharge side recess 72 on the other circumferential side. The downstream end 72j is the end of the first discharge side recess 72 on one circumferential side. In other words, the radial width of the first discharge side recess 72 narrows from the other circumferential side to one circumferential side.

As shown in FIG. 4, the second suction side recess 91 and the second discharge side recess 92 are recessed from the second end surface 210b toward the front side. For example, the axial depth T3 of the second suction side recess 91 and the axial depth T4 of the second discharge side recess 92 are the same. Note that the depths T3 and T4 may be different from each other. The depths T3 and T4 of the second suction side recess 91 and the second discharge side recess 92 are smaller than the depths T1 and T2 of the first suction side recess 71 and the first discharge side recess 72. Not limited to this, the depths T3 and T4 of the second suction side recess 91 and the second discharge side recess 92 may be larger than the depths T1 and T2 of the first suction side recess 71 and the first discharge side recess 72.

As shown in FIG. 6, the second suction side recess 91 and the second discharge side recess 92 are, for example, grooves extending in the circumferential direction. In this embodiment, when viewed in the axial direction, the second suction side recess 91 and the second discharge side recess 92 extend in an arc shape along the circumferential direction around the central axis J.

The radial outer edge of the second suction side recess 91 and the radial outer edge of the second discharge side recess 92 extend in an arc shape in the circumferential direction around the rotation axis of the outer rotor 32 when viewed from the axial direction. The radial inner edge of the second suction side recess 91 and the radial inner edge of the second discharge side recess 92 extend in an arc shape in the circumferential direction around the central axis J when viewed from the axial direction. Although not shown in the figure, the side surface facing the radially inward of the second suction side recess 91 and the side surface facing the radially inward of the second discharge side recess 92 overlap in the axial direction with multiple portions 32c that are the maximum diameter of the inner circumferential surface 32b facing the radially inward of the outer rotor 32 of the pump mechanism 30.

As shown by the thick arrows in FIG. 6, in the second suction side recess 91 and the second discharge side recess 92, oil flows from the other circumferential side to one circumferential side. In other words, in the second suction side recess 91 and the second discharge side recess 92, the other circumferential side, i.e., the side opposite to the side toward which the thick arrows in FIG. 6 point, is the upstream side, and the one circumferential side, i.e., the side toward which the thick arrows in FIG. 6 point, is the downstream side.

As shown in FIG. 6, the second suction side recess 91 in this embodiment has a gradually increasing radial width from the upstream end 91h to the downstream end 91j in the circumferential direction around the central axis J. The upstream end 91h is the end of the second suction side recess 91 on the other circumferential side. The downstream end 91j is the end of the second suction side recess 91 on one circumferential side. In other words, the radial width of the second suction side recess 91 increases from the other circumferential side to one circumferential side.

On the other hand, the radial width of the second discharge side recess 92 gradually narrows from the upstream end 92h to the downstream end 92j in the circumferential direction around the central axis J. The upstream end 92h is the end of the second discharge side recess 92 on the other circumferential side. The downstream end 92j is the end of the second discharge side recess 92 on one circumferential side. In other words, the radial width of the second discharge side recess 92 narrows from the other circumferential side to one circumferential side.

As shown in FIG. 4, a suction side flow path 81 is connected to the first suction side recess 71. The suction side flow path 81 opens to a side surface 71a facing radially inward of the first suction side recess 71. A discharge side flow path 82 is connected to the first discharge side recess 72. The discharge side flow path 82 opens to a side surface 72a facing radially inward of the first discharge side recess 72.

The bottom surface 71f of the first suction side recess 71 has a suction side flat surface 71c and a suction side inclined surface 71b. The bottom surface 71f is located on the rear side of the inner surface of the first suction side recess 71 and faces the front side. The bottom surface 72f of the first discharge side recess 72 has a discharge side flat surface 72c and a discharge side inclined surface 72b. The bottom surface 72f is located on the rear side of the inner surface of the first discharge side recess 72 and faces the front side.

The suction side flat surface 71c and the discharge side flat surface 72c are surfaces that intersect with the axial direction. The suction side flat surface 71c and the discharge side flat surface 72c are, for example, surfaces that are perpendicular to the axial direction. The suction side flat surface 71c and the discharge side flat surface 72c are, for example, parallel to the first end surface 210a. The suction side flat surface 71c of the first suction side recess 71 is located closer to the suction side flow path 81 than the suction side inclined surface 71b in the circumferential direction and is connected to the end of the suction side inclined surface 71b on the other side (upstream side) in the circumferential direction. The discharge side flat surface 72c of the first discharge side recess 72 is located closer to the discharge side flow path 82 than the discharge side inclined surface 72b in the circumferential direction and is connected to the end of the discharge side inclined surface 72b on one side (downstream side) in the circumferential direction.

The suction side inclined surface 71b and the discharge side inclined surface 72b are surfaces that are inclined with respect to the suction side flat surface 71c and the discharge side flat surface 72c. The suction side inclined surface 71b is located closer to the front as it moves from the suction side flat surface 71c to one side in the circumferential direction (downstream side). The discharge side inclined surface 72b is located closer to the front as it moves from the discharge side flat surface 72c to the other side in the circumferential direction (upstream side). The inclination angle θ1 of the suction side inclined surface 71b with respect to the suction side flat surface 71c and the inclination angle θ2 of the discharge side inclined surface 72b with respect to the discharge side flat surface 72c are, for example, the same as each other. The inclination angles θ1 and θ2 are preferably within a range of, for example, 15° to 35°. Note that the inclination angle θ1 and the inclination angle θ2 may be different from each other.

The first suction side recess 71 has a surface 71d that extends in the axial direction from a downstream end 71j on one circumferential side of the suction side inclined surface 71b toward the front side pump mechanism 30. Surface 71d is, for example, a surface perpendicular to the circumferential direction. The first discharge side recess 72 has a surface 72d that extends in the axial direction from an upstream end 72h on the other circumferential side of the discharge side inclined surface 72b toward the front side pump mechanism 30. Surface 72d is, for example, a surface perpendicular to the circumferential direction.

The bottom surface 91f of the second suction side recess 91 has an suction side flat surface 91c and an suction side inclined surface 91b. The bottom surface 91f is the surface located on the front side of the inner surface of the second suction side recess 91 and facing the rear side. The bottom surface 92f of the second discharge side recess 92 has a discharge side flat surface 92c and a discharge side inclined surface 92b. The bottom surface 92f is the surface located on the front side of the inner surface of the second discharge side recess 92 and facing the rear side.

The suction side flat surface 91c and the discharge side flat surface 92c are surfaces that intersect with the axial direction. The suction side flat surface 91c and the discharge side flat surface 92c are, for example, surfaces that are perpendicular to the axial direction. The suction side flat surface 91c and the discharge side flat surface 92c are, for example, parallel to the second end surface 210b. The suction side flat surface 91c of the second suction side recess 91 is located closer to the suction side flow path 81 than the suction side inclined surface 91b in the circumferential direction and is connected to the other (upstream) end of the suction side inclined surface 91b in the circumferential direction. The discharge side flat surface 92c of the second discharge side recess 92 is located closer to the discharge side flow path 82 than the discharge side inclined surface 92b in the circumferential direction and is connected to the one (downstream) end of the discharge side inclined surface 92b in the circumferential direction.

The suction side inclined surface 91b and the discharge side inclined surface 92b are surfaces that are inclined with respect to the suction side flat surface 91c and the discharge side flat surface 92c. The suction side inclined surface 91b is located toward the rear as it moves from the suction side flat surface 91c toward one side in the circumferential direction (downstream side). The discharge side inclined surface 92b is located toward the rear as it moves from the discharge side flat surface 92c toward the other side in the circumferential direction (upstream side).

The inclination angle θ3 of the suction side inclined surface 91b relative to the suction side flat surface 91c and the inclination angle θ4 of the discharge side inclined surface 92b relative to the discharge side flat surface 92c are, for example, the same as each other. The inclination angles θ3 and θ4 are preferably within the range of, for example, 0° to 15°. In this embodiment, the inclination angles θ3 and θ4 are smaller than the inclination angles θ1 and θ2. Note that the inclination angles θ3 and θ4 may be different from each other. The inclination angles θ3 and θ4 may be the same as the inclination angles θ1 and θ2, or may be larger than the inclination angles θ1 and θ2.

The second suction side recess 91 has a surface 91d that extends in the axial direction from a downstream end 91j on one circumferential side of the suction side inclined surface 91b toward the rear side pump mechanism 30. The surface 91d is, for example, a surface perpendicular to the circumferential direction. The second discharge side recess 92 has a surface 92d that extends in the axial direction from an upstream end 92h on the other circumferential side of the discharge side inclined surface 92b toward the rear side pump mechanism 30. The surface 92d is, for example, a surface perpendicular to the circumferential direction.

The bottom surface 71f of the first suction side recess 71 and the bottom surface 91f of the second suction side recess 91 in the suction section 61 at least partially overlap each other when viewed in the axial direction. The suction side inclined surface 71b of the first suction side recess 71 and the suction side inclined surface 91b of the second suction side recess 91 at least partially overlap each other when viewed in the axial direction. In this embodiment, the suction side flat surface 71c of the first suction side recess 71 and the suction side flat surface 91c of the second suction side recess 91 at least partially overlap each other when viewed in the axial direction. It is preferable that the bottom surface 71f of the first suction side recess 71 and the bottom surface 91f of the second suction side recess 91 overlap each other by, for example, 80% to 90% or more of their areas when viewed in the axial direction.

The bottom surface 71f of the first suction side recess 71 and the bottom surface 91f of the second suction side recess 91 have the same area when viewed in the axial direction, for example. The bottom surface 71f of the first suction side recess 71 and the bottom surface 91f of the second suction side recess 91 overlap each other entirely when viewed in the axial direction, for example. The suction side inclined surface 71b and the suction side inclined surface 91b have the same area when viewed in the axial direction, for example. The suction side inclined surface 71b and the suction side inclined surface 91b overlap each other entirely when viewed in the axial direction, for example. The suction side flat surface 71c and the suction side flat surface 91c have the same area when viewed in the axial direction, for example. The suction side flat surface 71c and the suction side flat surface 91c overlap each other entirely when viewed in the axial direction, for example.

In this embodiment, the boundary B1 between the suction side flat surface 71c and the suction side inclined surface 71b in the first suction side recess 71 overlaps with the boundary B2 between the suction side flat surface 91c and the suction side inclined surface 91b in the second suction side recess 91 when viewed in the axial direction.

The bottom surface 72f of the first discharge side recess 72 and the bottom surface 92f of the second discharge side recess 92 in the discharge section 62 overlap at least partially when viewed from the axial direction. The discharge side inclined surface 72b of the first discharge side recess 72 and the discharge side inclined surface 92b of the second discharge side recess 92 overlap at least partially when viewed from the axial direction. In this embodiment, the discharge side flat surface 72c of the first discharge side recess 72 and the discharge side flat surface 92c of the second discharge side recess 92 overlap at least partially when viewed from the axial direction. It is preferable that the bottom surface 72f of the first discharge side recess 72 and the bottom surface 92f of the second discharge side recess 92 overlap, for example, by 80% to 90% or more of their areas when viewed from the axial direction.

The bottom surface 72f of the first discharge side recess 72 and the bottom surface 92f of the second discharge side recess 92 have the same area when viewed in the axial direction, for example. The bottom surface 72f of the first discharge side recess 72 and the bottom surface 92f of the second discharge side recess 92 overlap each other entirely when viewed in the axial direction, for example. The discharge side inclined surface 72b and the discharge side inclined surface 92b have the same area when viewed in the axial direction, for example. The discharge side inclined surface 72b and the discharge side inclined surface 92b overlap each other entirely when viewed in the axial direction, for example. The discharge side flat surface 72c and the discharge side flat surface 92c have the same area when viewed in the axial direction, for example. The discharge side flat surface 72c and the discharge side flat surface 92c overlap each other entirely when viewed in the axial direction, for example.

In this embodiment, the boundary B3 between the discharge side flat surface 72c and the discharge side inclined surface 72b in the first discharge side recess 72 overlaps with the boundary B4 between the discharge side flat surface 92c and the discharge side inclined surface 92b in the second discharge side recess 92 when viewed in the axial direction.

In this specification, "a certain boundary portion overlaps with another boundary portion when viewed from the axial direction" means that at least a part of the certain boundary portion overlaps with a part of the other boundary portion when viewed from the axial direction.

As shown in FIG. 5, the first discharge side recess 72 has a semicircular notch 72k at the upstream end 72h. As shown in FIG. 6, the second discharge side recess 92 has a semicircular notch 92k at the upstream end 92h.

The suction side flow passage 81 is connected to a portion of the first suction side recess 71 where the bottom surface 71f is the suction side flat surface 71c. The connection position where the suction side flow passage 81 is connected to the first suction side recess 71 is away from the upstream end 71h to one side in the circumferential direction.

As shown in FIG. 2, the suction side flow passage 81 has a flow passage 81a extending radially outward from the connection position with the first suction side recess 71, a flow passage 81b extending from the radially outer end of the flow passage 81a to the rear side, and a flow passage 81c extending radially outward from the rear end of the flow passage 81b. The radially outer end of the flow passage 81c is connected to the suction port 51 that opens on the outer peripheral surface of the pump housing 210. In other words, the suction side flow passage 81 is a flow passage that connects the suction port 51 that opens on the surface facing radially outward of the pump housing 210 and the first suction side recess 71.

A cap 85 is fitted onto the intersection of flow passages 81a and 81b from the outer peripheral surface of the pump housing 210. A cap 86 is fitted onto the front end of flow passage 81b from the front end surface of the pump housing 210. The caps 85 and 86 close the openings of the drilled holes that make up flow passages 81a and 81b. The flow passage extending from the intersection of flow passages 81a and 81b to the cap 86 is a hole formed during the process of forming flow passage 81b using a mold, and is not an essential part of the suction side flow passage 81 in terms of its functionality as a flow passage.

As shown in FIG. 5, the discharge side flow path 82 is connected to a portion of the first discharge side recess 72 where the bottom surface 72f is the discharge side flat surface 72c. The connection position where the discharge side flow path 82 is connected to the first discharge side recess 72 is away from the downstream end 72j on the other side in the circumferential direction.

As shown in FIG. 3, the discharge side flow passage 82 has a flow passage 82a that extends radially outward from the connection position with the first discharge side recess 72. The radially outer end of the flow passage 82a is connected to the discharge port 52 that opens on the outer circumferential surface of the pump housing 210. The discharge side flow passage 82 has a flow passage 82b that branches off from the flow passage 82a and extends to the rear side. The rear end of the flow passage 82b reaches the rear end of the pump housing 210.

A relief valve 95 is disposed within the flow path 82b. The relief valve 95 has a valve body 95a that is movable along the axial direction, a coil spring 95b that pushes the valve body 95a toward the front, and a fixed portion 95c that supports the rear end of the coil spring 95b. The fixed portion 95c is male-threaded and is screwed into the rear end of the flow path 82b. The fixed portion 95c closes the opening at the rear end of the flow path 82b.

As shown in FIG. 3, the discharge side flow passage 82 has a flow passage 82c that extends downward from the flow passage 82b. The flow passage 82c branches off from a region in the flow passage 82b where the valve body 95a advances and retreats in the axial direction. The end of the flow passage 82c on the lower side in the figure is connected to the suction side flow passage 81 shown in FIG. 2. In the case of this embodiment, the flow passage 82c is connected at a position on the rear side of the position where the flow passage 81c connects to the flow passage 81b.

The relief valve 95 operates due to the pressure in the discharge side flow passage 82. When the valve body 95a retreats to the rear side by a predetermined distance or more due to oil pressure, the flow passages 82b and 82c are connected, and some of the oil in the discharge side flow passage 82 is returned to the suction side flow passage 81. This makes it possible to maintain the discharge pressure of the electric pump 200 below the limit value. Furthermore, by installing the relief valve 95, damage to piping and equipment due to abnormal pressure can be suppressed.

When the pump mechanism 30 is driven by the motor 220, oil is sucked into the suction side flow passage 81 from the suction port 51. As shown by the thick arrow in FIG. 2, the oil sucked into the suction side flow passage 81 flows through the flow passage 81c, the flow passage 81b, and the flow passage 81a in this order, and flows into the first suction side recess 71. As shown by the arrow F in FIG. 4, the oil sucked into the first suction side recess 71 from the suction side flow passage 81 by the pump action is sucked into the pump mechanism 30 while flowing through the first suction side recess 71. More specifically, the oil in the first suction side recess 71 is sucked between the outer teeth 31a of the inner rotor 31 and the inner teeth 32a of the outer rotor 32. The oil sucked into the pump mechanism 30 moves to one side in the circumferential direction inside the pump housing portion 211b as the inner rotor 31 and the outer rotor 32 rotate. A part of the oil sucked into the pump mechanism 30 also flows into the second suction side recess 91. The oil in the second suction side recess 91 flows, for example, to one side in the circumferential direction and is again sucked between the external teeth 31a of the inner rotor 31 and the internal teeth 32a of the outer rotor 32.

In the electric pump 200 having such a configuration, the oil moved to one side in the circumferential direction in the pump housing portion 211b by the pump mechanism 30 flows into the first discharge side recess 72 and the second discharge side recess 92. The oil that flows into the first discharge side recess 72 flows to one side in the circumferential direction in the first discharge side recess 72 and is discharged to the discharge side flow path 82. The oil that flows into the second discharge side recess 92, for example, flows to one side in the circumferential direction and is again sucked between the outer teeth 31a of the inner rotor 31 and the inner teeth 32a of the outer rotor 32, and is discharged to the discharge side flow path 82 through the first discharge side recess 72 as shown by the arrow F in FIG. 4. As shown by the thick arrow in FIG. 3, the oil discharged to the discharge side flow path 82 flows through the flow path 82a and is discharged from the discharge port 52 to the outside of the electric pump 200.

In the electric pump 200 of this embodiment, the bottom surface 71f of the first suction side recess 71 and the bottom surface 91f of the second suction side recess 91 each have a suction side inclined surface 71b, 91b that is inclined with respect to a plane intersecting the axial direction. The suction side inclined surface 71b of the first suction side recess 71 and the suction side inclined surface 91b of the second suction side recess 91 overlap each other at least partially when viewed from the axial direction, and are inclined in a direction approaching each other in the axial direction as they approach one side in the circumferential direction around the central axis J. Therefore, the oil in the first suction side recess 71 and the oil in the second suction side recess 91 are guided in the axial direction toward the inside of the pump accommodating portion 211b while flowing toward one side in the circumferential direction along the suction side inclined surfaces 71b, 91b as the pump mechanism 30 rotates toward one side in the circumferential direction.

This allows the pump mechanism 30 to suck oil from the first suction side recess 71 and the second suction side recess 91 while maintaining a balance between the force toward the front side that the pump mechanism 30 receives from the oil in the first suction side recess 71 and the force toward the rear side that the pump mechanism 30 receives from the oil in the second suction side recess 91. Therefore, the pump mechanism 30 can be rotated while being appropriately pressed from both axial sides by the oil pressure. Therefore, it is possible to suppress the inner rotor 31 and the outer rotor 32 from tilting in the pump housing portion 211b, and the inner rotor 31 and the outer rotor 32 from vibrating. This allows the inner rotor 31 and the outer rotor 32 to rotate stably. Therefore, it is possible to suppress a decrease in the amount of oil sucked out from the pump mechanism 30 and pulsation of the suction pressure. In addition, it is possible to reduce friction between the inner rotor 31 and the outer rotor 32 and the inner surface of the pump housing portion 211b.

On the other hand, the discharge side inclined surfaces 72b, 92b facing each other in the axial direction on the discharge section 62 side are inclined in a direction away from each other in the axial direction as they go to one side (downstream side) in the circumferential direction. Therefore, the oil discharged from the pump mechanism 30 is efficiently guided into the first discharge side recess 72 and the second discharge side recess 92 along the discharge side inclined surfaces 72b, 92b. As a result, the oil can be discharged from the pump mechanism 30 to the first discharge side recess 72 and the second discharge side recess 92 while maintaining a balance between the force of the oil discharged from the pump mechanism 30 to the first discharge side recess 72 toward the rear side and the force of the oil discharged from the pump mechanism 30 to the second discharge side recess 92 toward the front side. Therefore, the inner rotor 31 and the outer rotor 32 can be prevented from tilting in the pump accommodating section 211b, and the inner rotor 31 and the outer rotor 32 can be prevented from vibrating. As a result, the inner rotor 31 and the outer rotor 32 can be rotated stably. This makes it possible to suppress a decrease in the amount of oil discharged from the pump mechanism 30 and pulsation of the discharge pressure.

In this way, the balance between the suction amount and suction pressure of the oil for the pump mechanism 30 and the discharge amount and discharge pressure is equalized on the suction side and the discharge side, which reduces friction between the inner rotor 31 and the outer rotor 32 and the inner surface of the pump housing 211b, and suppresses rotation loss of the inner rotor 31. Furthermore, it is possible to reduce wear between the inner rotor 31 and the outer rotor 32 and the inner surface of the pump cover 212 and the inner surface of the pump housing 211b. By reducing wear, heat generation and wear powder can be suppressed, and adverse effects on the electric pump 200 can be suppressed.

In this embodiment, on the suction section 61 side, a boundary B1 between the suction side flat surface 71c and the suction side inclined surface 71b of the first suction side recess 71 overlaps, as viewed in the axial direction, a boundary B2 between the suction side flat surface 91c and the suction side inclined surface 91b of the second suction side recess 91. As a result, the suction side inclined surfaces 71b and 91b that face each other in the axial direction overlap substantially entirely, so that at a circumferential position where oil in one first suction side recess 71 flows along the suction side inclined surface 71b, oil in the other second suction side recess 91 also flows along the suction side inclined surface 91b.
On the other hand, on the discharge portion 62 side, a boundary B3 between the discharge-side flat surface 72c and the discharge-side inclined surface 72b in the first discharge-side recess 72 overlaps, as viewed in the axial direction, a boundary B4 between the discharge-side flat surface 92c and the discharge-side inclined surface 92b in the second discharge-side recess 92. As a result, the discharge-side inclined surfaces 72b and 92b that face each other in the axial direction overlap substantially entirely, so that at a circumferential position where oil in one first discharge-side recess 72 flows along the discharge-side inclined surface 72b, oil in the other second discharge-side recess 92 also flows along the discharge-side inclined surface 92b.
This makes it easier to maintain a balance between the pressures that the pump mechanism 30 receives from the oil on both the suction side and the discharge side, thereby making the rotation of the inner rotor 31 more stable during suction and discharge.

In addition, in this embodiment, the suction side flat surface 71c of the first suction side recess 71 on the pump housing 210 side and the discharge side flat surface 72c of the first discharge side recess 72 are arranged at the same position in the axial direction. This makes it easier to axially align the positions of the suction side flow passage 81 and the discharge side flow passage 82 connected to the first suction side recess 71 and the first discharge side recess 72. This makes it easier for oil to flow from the suction side flow passage 81 to the discharge side flow passage 82 compared to when the suction side flat surface 71c and the discharge side flat surface 72c are in different axial positions. This results in more stable rotation of the pump mechanism 30.

In this embodiment, the first suction side recess 71 and the second suction side recess 91 each have a surface 71d, 91d that extends axially from one circumferential end of the suction side inclined surface 71b, 91b toward the pump mechanism 30. The first discharge side recess 72 and the second discharge side recess 92 each have a surface 72d, 92d that extends axially from the other circumferential end, upstream side, of the discharge side inclined surface 72b, 92b toward the pump mechanism 30. In this way, the surfaces 71d, 91d that rise from the bottom surfaces 71f, 91f toward the pump mechanism 30 make it easier for oil to be sucked into the pump mechanism 30, and the surfaces 72d, 92d that extend from the pump mechanism 30 toward the bottom surfaces 72f, 92f make it easier for oil to be discharged from the pump mechanism 30. In addition, the axial surfaces 71d, 91d, 72d, and 92d allow the axial depth of each recess 71, 72, 91, and 92 to be increased, suppressing the occurrence of a reaction in the flow of oil sucked in or discharged from the pump mechanism 30. As a result, oil pulsation is reduced, allowing the oil to flow smoothly.

When viewed from the axial direction, the first suction side recess 71, the first discharge side recess 72, the second suction side recess 91, and the second discharge side recess 92 extend in an arc shape along the circumferential direction around the central axis. This allows the oil flowing in from the suction side flow path 81 to flow along the arcs of the first suction side recess 71 and the second suction side recess 91 while being guided to the pump mechanism 30 and efficiently sucked in. In addition, the oil discharged from the pump mechanism 30 is efficiently discharged to the discharge side flow path 82 while flowing along the arcs of the first discharge side recess 72 and the second discharge side recess 92.

As described above, in the electric pump 200 of this embodiment, by suppressing vibration of the pump mechanism 30, not only is friction reduced, but pump pulsation can also be reduced, improving efficiency.

Without departing from the spirit of the present invention, the configurations (elements) described in the above embodiments, modifications, and notes may be combined, and additions, omissions, substitutions, and other modifications of the configurations are possible.

22...rotor, 30...pump mechanism, 31...inner rotor, 31a...external teeth, 32...outer rotor, 32a...internal teeth, 61...suction portion, 62...discharge portion, 71...first suction side recess, 71b...suction side inclined surface, 71c...suction side flat surface, 71d, 72d, 91d, 92d...(axially extending) surface, 72b...discharge side inclined surface, 72c...discharge side flat surface, 71f, 72f, 91f, 92f... bottom surface, 72... first discharge side recess, 91... second suction side recess, 91b... suction side inclined surface, 91c... suction side flat surface, 92... second discharge side recess, 92b... discharge side inclined surface, 92c... discharge side flat surface, 200... electric pump, 210... pump housing, 210a... first end surface, 210b... second end surface, 211b... pump housing, B1, B2, B3, B4... boundary portion, J... central axis

Claims (5)

a pump mechanism including an inner rotor rotatable about a central axis extending in an axial direction and having external teeth, and an outer rotor surrounding the inner rotor and having internal teeth meshing with the external teeth;
a pump housing including a pump accommodating portion that accommodates the pump mechanism, and a suction portion and a discharge portion that are connected to the pump accommodating portion;
Equipped with
The pump housing comprises:
a first end surface that faces the pump mechanism in an axial direction on one axial side of the pump mechanism;
a second end surface that faces the pump mechanism in the axial direction on the other axial side of the pump mechanism and axially sandwiches the pump mechanism between the second end surface and the first end surface;
having
The suction section is
a first suction side recess recessed from the first end surface to one side in the axial direction;
a second suction side recess recessed from the second end surface to the other axial direction;
having
The discharge unit is
a first discharge side recess recessed from the first end surface to one side in the axial direction;
a second discharge side recess recessed from the second end surface to the other axial direction;
having
a bottom surface of the first suction side recess and a bottom surface of the second suction side recess each have a suction side inclined surface inclined with respect to a plane intersecting an axial direction,
a bottom surface of the first discharge side recess and a bottom surface of the second discharge side recess each have a discharge side inclined surface inclined with respect to a plane intersecting an axial direction,
the suction side inclined surface of the first suction side recess and the suction side inclined surface of the second suction side recess at least partially overlap each other when viewed in the axial direction, and are inclined in a direction approaching each other in the axial direction toward one side in a circumferential direction about the central axis,
the discharge-side inclined surface of the first discharge-side recess and the discharge-side inclined surface of the second discharge-side recess at least partially overlap each other when viewed in the axial direction, and are inclined in directions away from each other in the axial direction toward one side in the circumferential direction,
a bottom surface of the first suction side recess and a bottom surface of the second suction side recess each have a suction side flat surface that intersects with an axial direction and is connected to the other side of the suction side inclined surface in the circumferential direction,
a bottom surface of the first discharge side recess and a bottom surface of the second discharge side recess each have a discharge side flat surface that intersects with an axial direction and is connected to one side of the discharge side inclined surface in a circumferential direction,
a boundary portion between the suction side flat surface and the suction side inclined surface in the first suction side recess overlaps with a boundary portion between the suction side flat surface and the suction side inclined surface in the second suction side recess when viewed in the axial direction,
An electric pump, wherein a boundary portion between the discharge side flat surface and the discharge side inclined surface in the first discharge side recess overlaps with a boundary portion between the discharge side flat surface and the discharge side inclined surface in the second discharge side recess when viewed in the axial direction. The electric pump according to claim 1, wherein the suction side flat surface of the first suction side recess and the discharge side flat surface of the first discharge side recess are disposed at the same position relative to each other in the axial direction. 3 . The electric pump according to claim 1 , wherein the first suction side recess and the second suction side recess each have a surface that extends in the axial direction from one circumferential end of the suction side inclined surface toward the pump mechanism. 4. The electric pump according to claim 1, wherein the first discharge side recess and the second discharge side recess each have a surface that extends in the axial direction from an end portion on the other side in the circumferential direction of the discharge side inclined surface toward the pump mechanism. When viewed from the axial direction,
5. The electric pump according to claim 1, wherein the first suction side recess, the second suction side recess, the first discharge side recess, and the second discharge side recess extend in an arc shape along a circumferential direction around the central axis.

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