JP7552041B2 - Electric pump - Google Patents

Description

The present invention relates to an electric pump.

Conventionally, electric pumps are known to have a configuration in which a pump body houses a motor, a pump mechanism, and a control board that controls the motor.

Patent No. 5969342

In an electric pump where the control board and motor are aligned in the axial direction, for example, if a large control board is used to achieve high output, the control board will protrude significantly in the radial direction of the motor. This will result in a larger electric pump.

According to one aspect of the present invention, there is provided an electric pump comprising a motor having a rotor rotatable around a central axis, a pump mechanism connected to the motor, a control board located radially outside the motor, a motor housing that houses the motor, and a joint bus bar that connects the control board and the motor. The electric pump has a board holder that holds the control board and can be attached to the motor housing. The joint bus bar is insert molded into the board holder.

According to this aspect of the present invention, an electric pump is provided that can use a large control board while suppressing the overall size, and is easy to assemble.

FIG. 1 is a cross-sectional view of an electric pump according to an embodiment. FIG. 2 is a perspective view showing an internal structure of the electric pump according to the embodiment. FIG. 3 is a side view showing the internal structure of the electric pump according to the embodiment. FIG. 4 is a partial perspective view showing the board unit of the embodiment. FIG. 5 is a diagram showing a connection structure between a stator and a control board according to the embodiment.

The following describes an electric oil pump as an embodiment of an electric pump. The electric oil pump of the embodiment is used to supply oil to equipment mounted on a vehicle, etc.

In the drawings referred to below, an XYZ coordinate system is appropriately shown as a three-dimensional Cartesian coordinate system. 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 the shaft 21 of the motor 20 described below. The Y-axis direction is a direction perpendicular to the X-axis, parallel to the depth 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 up-down direction in FIG. 1. In all of the X-axis, Y-axis, and Z-axis directions, the side toward which the arrows shown in the drawings point 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 (θ direction), is simply referred to as the "circumferential direction."

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 front side (+X side) corresponds to one axial side in this invention. The rear side (-X side) corresponds to the other axial side in this invention.

As shown in FIGS. 1 and 2 , an electric oil pump 100 of the present embodiment includes a pump body 10 , a motor 20 , a pump mechanism 30 , and a board unit 140 having a control board 40 .
The pump body 10 has a motor housing 11 that houses the motor 20, a pump housing 12 that houses the pump mechanism 30, and a board housing 13 on which a control board 40 is mounted. In this embodiment, the motor housing 11, the pump housing 12, and the board housing 13 are part of a single member.

The motor housing 11 is located on the rear side (-X side) of the pump body 10. The motor housing 11 is cylindrical and extends in the axial direction. The motor housing 11 has a first accommodating recess 11a that is a recess that opens to the rear side. The first accommodating recess 11a is closed from the rear side by a bearing holder 26, which will be described later.

The pump housing 12 is located on the front side (+X side) of the pump body 10. The pump housing 12 has a second accommodating recess 12a that is a recess that opens to the front side. The electric oil pump 100 has a pump cover 12b that covers the second accommodating recess 12a from the front side. The pump cover 12b is a circular plate-shaped member when viewed from the axial direction. The pump cover 12b is screwed to the pump housing 12.

The board housing 13 is located on the side of the motor housing 11 and the pump housing 12. The board housing 13 is located on the illustrated lower side (-Z side) of the motor housing 11 and the pump housing 12. The board housing 13 is roughly rectangular when viewed from the radial outside. The board housing 13 has a third accommodating recess 13a that opens toward the illustrated lower side of the pump body 10. The board unit 140, which will be described later, is attached to the board housing 13 from the illustrated lower side.

The pump body 10 has a first through hole 10a and a second through hole 10b inside. The first through hole 10a connects the first accommodation recess 11a of the motor housing 11 and the second accommodation recess 12a of the pump housing 12 in the axial direction. The second through hole 10b connects the first accommodation recess 11a of the motor housing 11 and the third accommodation recess 13a of the board housing 13 in the radial direction. In other words, the second through hole 10b is an accommodation portion that extends radially between the motor housing 11 and the board housing 13 and accommodates the joint bus bars 51a to 51c described later. The accommodation portion is not limited to a through hole, and may be, for example, a groove that opens in the axial direction and extends radially. If the accommodation portion is a groove, the opening of the groove may be blocked by a bearing holder 26 described later.

The motor 20 includes a rotor 22 having a shaft 21, a stator 23, a busbar unit 120, a bearing holder 26, a first bearing 27, and a second bearing 28. The busbar unit 120 includes a busbar assembly 24 and a busbar cover 25. The bearing holder 26 covers the opening of the motor housing 11. In this embodiment, the bearing holder 26 also serves as the motor cover.

The shaft 21 is a cylindrical member extending along the central axis J. The rotor 22 has the shaft 21, a rotor core 22a fixed to the outer peripheral surface of the shaft 21, and a plurality of rotor magnets 22b fixed to the rotor core 22a. The rotor magnets 22b may be annular magnets that surround the shaft 21.

The shaft 21 is supported by a first bearing 27 and a second bearing 28 so that it can rotate about its axis. The first bearing 27 supports a portion of the shaft 21 that is rearward of the rotor core 22a. The second bearing 28 supports a portion of the shaft 21 that is frontward of the rotor core 22a. The shaft 21 protrudes to the front side through the inner hole of the second bearing 28. The front end of the shaft 21 is connected to the pump mechanism 30.

The stator 23 includes an annular stator core 23a that surrounds the rotor 22, an insulator 23b that is attached to the teeth of the stator core 23a, and a coil 23c that is wound around the teeth via the insulator 23b. The stator core 23a is fixed to the inner circumferential surface of the cylindrical motor housing 11.

The busbar unit 120 is located between the stator 23 and the bearing holder 26. The busbar unit 120 has a busbar assembly 24 and a busbar cover 25 arranged side by side in the axial direction. The busbar assembly 24 faces the stator 23 in the axial direction. The busbar cover 25 faces the bearing holder 26 in the axial direction.

As shown in Figures 2 and 3, the busbar assembly 24 has busbars 24a, 24b, and 24c, and a resin busbar holder 24d that holds the busbars 24a to 24c. The three busbars 24a to 24c are insert molded into the busbar holder 24d. The busbars 24a to 24c may be fixed by screws or snap fit.

As shown in FIG. 1, the busbar assembly 24 is located on the rear side of the stator 23. The busbar assembly 24 is inserted into the first accommodating recess 11a of the motor housing 11 from the rear side. As shown in FIG. 3 and FIG. 5, one end of the three busbars 24a to 24c is hook-shaped. The hook-shaped ends of the busbars 24a, 24b, and 24c are each connected to the coil wire 23d extending from the coil 23c to the rear side. The other ends of the busbars 24a to 24c are located at the end of the busbar holder 24d on the board housing 13 side (the lower side in the figure). The ends of the busbars 24a, 24b, and 24c located at the bottom of the busbar holder 24d are each connected to the joint busbars 51a, 51b, and 51c described below.

The busbar cover 25 is located on the rear side of the busbar assembly 24. The busbar cover 25 is inserted into the first accommodating recess 11a from the rear side. The busbar cover 25 is annular when viewed from the axial direction. The busbar cover 25 covers the busbar assembly 24 from the rear side. The busbar cover 25 has a groove portion 25a that is annular when viewed from the axial direction on the surface facing the rear side. An elastic member 25b made of an O-ring is placed inside the groove portion 25a.

The bearing holder 26 is located on the rear side of the busbar unit 120. The bearing holder 26 has a cylindrical portion 26a extending along the central axis J, and a holder body 26b extending radially outward from the outer circumferential surface of the cylindrical portion 26a. The cylindrical portion 26a opens on both sides in the axial direction. The first bearing 27 is inserted into the opening on the front side of the cylindrical portion 26a. The cylindrical portion 26a has a stepped surface 26c on part of its inner circumferential surface that faces the front side. Movement of the first bearing 27 to the rear side is restricted by the stepped surface 26c.

The bearing holder 26 extends radially outward from the busbar unit 120. The bearing holder 26 covers the busbar unit 120 from the rear side. The bearing holder 26 is screwed to the pump body 10 on the radially outer side of the busbar unit 120. The surface of the bearing holder 26 facing the front side is axially opposite the surface of the busbar cover 25 facing the rear side.

The motor housing 11 has a groove 11c that opens toward the rear side on the end face surrounding the first accommodating recess 11a. The groove 11c is annular when viewed from the axial direction. A seal member 29 made of an O-ring is disposed inside the groove 11c. The seal member 29 provides an airtight seal between the face of the bearing holder 26 facing the front side and the end face of the motor housing 11 facing the rear side.

When the bearing holder 26 blocks the first housing recess 11a from the rear side, the elastic member 25b is sandwiched between the bearing holder 26 and the bus bar cover 25 in the axial direction. The elastic member 25b is compressed in the axial direction by the bus bar cover 25 and the bearing holder 26. The elastic member 25b exerts an elastic force on the bus bar cover 25 and the bearing holder 26, moving them away from each other in the axial direction. Because the bearing holder 26 is fixed to the motor housing 11, the elastic return force of the elastic member 25b acts in a direction that pushes the bus bar cover 25 toward the front side.

The busbar cover 25 functions as a spacer inserted between the busbar assembly 24 and the bearing holder 26. The busbar cover 25 is pushed toward the front side by the elastic member 25b, thereby pushing the busbar assembly 24 toward the front side. The front end 24e of the busbar assembly 24 abuts against the step surface 11b facing the rear side of the motor housing 11. With this configuration, the busbar assembly 24 and the busbar cover 25 are fixed in the axial direction. The end 24e of the busbar assembly 24 may abut against the stator 23.

In the electric oil pump 100 of this embodiment, the busbar unit 120 can be fixed in the first accommodating recess 11a simply by fixing the bearing holder 26 to the motor housing 11 during the assembly process. Therefore, the electric oil pump 100 of this embodiment has a configuration that allows an operator to assemble it efficiently.

The busbar unit 120 may be a member in which the busbar cover 25 and the busbar assembly 24 are fixed together. For example, the busbar cover 25 and the busbar holder 24d may be configured as part of a single component. The busbar cover 25 and the busbar assembly 24 may be connected together by adhesive, screwing, or other methods.

A breather 26e is inserted into the rear end of the cylindrical portion 26a. The breather 26e allows air to flow between the inside and outside of the bearing holder 26. The inner space of the bearing holder 26 is connected to the inside of the first accommodating recess 11a via the cylindrical portion 26a. The first accommodating recess 11a is connected to the second accommodating recess 12a and the third accommodating recess 13a. Therefore, the breather 26e allows air to flow between the internal space of the pump body 10 and the external space.

In the electric oil pump 100, the bearing holder 26 that holds the first bearing 27 functions as a motor cover, making manufacturing easier and improving assembly workability compared to a configuration in which the motor cover and bearing holder are separate parts.
Furthermore, in the electric oil pump 100, the bearing holder 26, which functions as a motor cover, has a cylindrical portion 26a with a through hole that axially passes through the bearing holder 26, and holds a breather 26e at the rear end of the cylindrical portion 26a, and holds a first bearing 27 at the front end of the cylindrical portion 26a. With this configuration, the first bearing 27 and the breather 26e are aligned in the axial direction in the bearing holder 26, so that the space around the first bearing 27 inside the first accommodating recess 11a can be effectively utilized. This makes it possible to prevent the electric oil pump 100 from becoming large.

The second bearing 28 is inserted from the rear side into the first through hole 10a that connects the first accommodating recess 11a and the second accommodating recess 12a. Inside the first through hole 10a, 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 first through hole 10a is a stepped hole having multiple steps inside. The first through hole 10a has a first step surface 10c and a second step surface 10d inside, both of which face the rear side. Therefore, the inner diameter of the first through hole 10a becomes smaller each time it passes through the steps toward the front side. The oil seal 15 is located between the first step surface 10c and the fixed ring 16 in the axial direction. The fixed ring 16 abuts against the second step surface 10d from the rear side. The fixed ring 16 supports the wave washer 17 with its surface facing the rear side. The wave washer 17 presses the outer ring of the second bearing 28 from the front side toward the rear 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 front end of the shaft 21 passes through the first through hole 10a and reaches the second accommodating recess 12a.

The pump mechanism 30 has an inner rotor 31 connected to the front end of the shaft 21, and an outer rotor 32 surrounding the inner rotor 31 from the radial outside. The inner rotor 31 and the outer rotor 32 are housed between the second housing recess 12a and the pump cover 12b. The inner rotor 31 and the outer rotor 32 each have a trochoid tooth profile. In other words, the pump mechanism 30 is a trochoid pump.

The board unit 140 includes a control board 40, a board holder 141 that holds the control board 40 from the radial outside, and three joint bus bars 51a, 51b, and 51c that are insert molded into the board holder 141.

The board holder 141 is a box-shaped member that opens toward the board housing 13 (+Z side). The control board 40 is fixed to an opening 141d that faces the upper side of the board holder 141 in the figure. The board holder 141 has a bottom wall 141e that faces the surface of the control board 40 that faces the side opposite the motor 20 (the lower surface in the figure). In this embodiment, the control board 40 is screwed to the bottom wall 141e.
In this embodiment, the board holder 141 is made of resin and has a connector 141b in which a plurality of metal terminals 141a are insert-molded, and a bus bar support portion 141c in which a plurality of joint bus bars 51a to 51c are insert-molded.

The multiple metal terminals 141a of the connector 141b are connected to the front end of the control board 40. The joint bus bars 51a to 51c are connected to the rear end of the control board 40. The multiple metal terminals 141a and the joint bus bars 51a to 51c are soldered to the control board 40.

The busbar support portion 141c is part of the board holder 141 and is made of resin. The busbar support portion 141c protrudes from the rear end of the board holder 141 towards the motor 20 (upper side in the figure). In other words, the busbar support portion 141c protrudes from the open end of the board holder 141 towards the motor 20. The joint busbars 51a to 51c extend from the connection position with the control board 40 towards the rear side and are inserted into the busbar support portion 141c. The joint busbars 51a to 51c extend radially inside the busbar support portion 141c. The joint busbars 51a to 51c protrude from the tip of the busbar support portion 141c towards the motor 20.

The joint bus bars 51a to 51c connect the motor 20 and the control board 40. The joint bus bars 51a to 51c and the bus bar support portion 141c are inserted from the radially outer side into the second through hole 10b that connects the third accommodating recess 13a and the first accommodating recess 11a. The tips of the joint bus bars 51a to 51c are located within the first accommodating recess 11a and overlap the bus bar assembly 24 when viewed from the axial direction. The joint bus bars 51a to 51c are screwed to the bus bars 24a to 24c of the bus bar assembly 24 by the screws 53a to 53c. This electrically connects the control board 40 and the motor 20 via the joint bus bars 51a to 51c.

The board unit 140 is fixed to the board housing 13 of the pump body 10 with the control board 40 facing the motor 20. In this embodiment, the board holder 141 of the board unit 140 is screwed to the board housing 13. The control board 40 is enclosed between the pump body 10 and the board holder 141.

In the electric oil pump 100 of this embodiment, the control board 40 is disposed along the side surface of the motor 20. The control board 40 has joint bus bars 51a, 51b, and 51c that are located inside the second through-hole 10b of the pump body 10 and electrically connect the motor 20 and the control board 40. With this configuration, the plate surface of the control board 40 faces in the radial direction, and the motor 20 and the control board 40 are connected in the radial direction by the joint bus bars 51a to 51c, so that the control board 40 does not protrude significantly in the radial direction. This makes it possible to prevent the electric oil pump 100 from becoming large.
Furthermore, the use of the joint bus bars 51a to 51c made of metal plate material facilitates connection inside the pump body 10. The electric oil pump 100 of this embodiment can be manufactured efficiently.

The electric oil pump 100 of this embodiment also includes a board unit 140 in which the control board 40, board holder 141, and joint bus bars 51a to 51c are assembled as a single component. With this configuration, the control board 40 can be attached by mounting the board unit 140 to the board housing 13 and connecting the joint bus bars 51a to 51c to the bus bars 24a to 24c. The electric oil pump 100 of this embodiment can be manufactured efficiently with few man-hours.

In this embodiment, the joint bus bars 51a to 51c and the control board 40 are connected on the board holder 141. Therefore, there is no need to perform soldering on the side of the pump body 10, as is the case when the control board 40 is fixed to the pump body 10. This improves the workability during assembly work. In addition, the control board 40 can be easily removed from the pump body 10 during repairs.

In this embodiment, the joint bus bars 51a to 51c are supported by bus bar support parts 141c that protrude from the board holder 141 towards the motor 20, and the bus bar support parts 141c are inserted into the second through holes 10b together with the joint bus bars 51a to 51c. As a result, the resin bus bar support parts 141c are positioned between the inner wall surface of the second through holes 10b and the joint bus bars 51a to 51c, making it difficult for short circuits to occur due to contact or proximity between the joint bus bars 51a to 51c and the pump body 10.

1, in this embodiment, the joint bus bar 51b has a first portion 151 that extends radially outward from a connection position with the motor 20 and is inserted into the bus bar support portion 141c, a second portion 152 that extends from a connection position with the control board 40 toward the bottom wall 141e of the board holder 141, and a third portion 153 that connects the first portion 151 and the second portion 152. The other joint bus bars 51a, 51c have a similar configuration. That is, the joint bus bars 51a to 51c have a shape that is bent roughly into a U shape.
The joint bus bars 51a to 51c are insert molded into the board holder 141, and both ends are exposed from the resin portion of the board holder 141. The third portions 153 of the joint bus bars 51a to 51c protrude from the inner wall surface of the board holder 141 to the front side (+X side) and connect to the ends of the second portions 152 through the gap between the control board 40 and the bottom wall 141e. The second portions 152 extend from the connection position with the third portions 153 toward the control board 40.
According to this configuration, second portions 152 of joint bus bars 51a to 51c are arranged with their tips facing the opening 141d. This allows control board 40 to be installed through opening 141d of board holder 141 and easily connected to joint bus bars 51a to 51c. An operator can efficiently assemble board unit 140.
Furthermore, because the third portions 153 of the joint bus bars 51a to 51c and the control board 40 partially overlap when viewed from the radial direction, it is easy to prevent the board holder 141 from becoming large in the axial direction (X-axis direction).

The connections between the joint bus bars 51a-51c and the bus bars 24a-24c are located on the surface facing the rear of the bus bar assembly 24. This allows the screws 53a-53c that secure the joint bus bars 51a-51c and the bus bars 24a-24c to be tightened axially within the openings of the motor housing 11. This makes it easier to assemble the electric oil pump 100.

In this embodiment, the multiple joint bus bars 51a to 51c are supported by one bus bar support portion 141c. This makes it easier to assemble the electric oil pump 100 because only one member is inserted into the second through hole 10b. In addition, because the multiple joint bus bars 51a to 51c are fixed in a state where they are positioned relative to each other, the multiple joint bus bars 51a to 51c are less likely to become misaligned, making it easier to screw them to the bus bars 24a to 24c. Note that each of the joint bus bars 51a, 51b, and 51c may be supported by a separate bus bar support portion.

10...pump body, 11...motor housing, 13...board housing, 20...motor, 22...rotor, 23...stator, 24a-24c...busbar, 30...pump mechanism, 40...control board, 51a-51c...joint busbar, 100...electric oil pump, 140...board unit, 141...board holder, 141c...busbar support, 141d...opening, J...center axis

Claims (6)

A motor having a rotor that can rotate around a central axis;
a pump mechanism coupled to the motor;
A control board located radially outside the motor;
a motor housing that houses the motor;
a joint bus bar connecting the control board and the motor;
Equipped with
a box-shaped board holder that holds the control board, is mountable to the motor housing, and opens toward the motor housing;
The substrate holder includes:
an opening portion that opens toward the motor side ;
a bottom wall facing a surface of the control board facing away from the motor ,
the control board is disposed inside the opening of the box-shaped board holder;
the joint bus bar is insert molded into the board holder;
The joint bus bar is
a first portion extending radially outward from a connection position with the motor;
A second portion that is connected to the control board;
a third portion connecting the first portion and the second portion,
The third portion is
a motor shaft extending between the control board and the bottom wall and connected to an end of the second portion;
A tip of the second portion is disposed toward the opening side and extends from a radially outer side toward the control board and the motor.
Electric pump. the substrate holder has a bus bar support portion protruding from an open end of the substrate holder toward the motor;
The electric pump according to claim 1. The bus bar support portion holds a plurality of the joint bus bars.
The electric pump according to claim 2. The joint bus bar is
the first portion to be inserted into the bus bar support portion;
the second portion extending from a connection position with the control board toward the bottom wall of the board holder ,
The electric pump according to claim 2 or 3. a pump body capable of accommodating the motor and the control board;
The pump body includes:
a motor housing that houses the motor;
a board housing that houses the control board;
a housing portion extending radially between the motor housing and the board housing;
having
The joint bus bar passes through the housing and connects the control board and the motor.
The electric pump according to any one of claims 1 to 4. The motor is
a stator radially opposed to the rotor;
a bus bar located on one axial side of the stator and electrically connected to the stator;
having
The joint bus bar electrically connects the bus bar and the control board.
The electric pump according to any one of claims 1 to 5.

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