Motor unit

Abstract

A motor unit 2 includes: an electric motor 10; a control board 20 arranged along a direction orthogonal to the axial direction of the electric motor 10; and a housing 5 having a motor storage chamber 51, a board storage chamber 52, and a motor cover 55 provided between the storage chambers 51, 52 as a partition wall. An axial pin-shaped terminal 32 connected to a coil 17 is inserted via a terminal insertion hole 55b provided in the motor cover 55 into a terminal insertion hole 21 provided in the control board 20 and thereby electrically connects the coil 17 and the (control unit of the) control board 20. The pin-shaped terminal 32 is held by the motor cover 55 via a terminal holding section 53 for insulating and holding the pin-shaped terminal 32, and an annular elastic seal 37 provided on the outer periphery of the terminal holding section 53.

Description

Motor Unit

[0001] The present invention relates to a motor unit.

[0002] For example, Patent Document 1 listed below describes an electric pump for a vehicle that includes a motor unit and a pump unit driven by the output of the motor unit. The motor unit includes a three-phase electric motor, a board (control board) arranged along a direction (radial direction) perpendicular to the axial direction of the electric motor and provided with a control unit that controls the operation of the electric motor, and a housing that houses the electric motor and the control board in a mutually isolated state. Terminals of three-phase coils (U-phase, V-phase, and W-phase coils) provided on the motor stator are directly inserted into corresponding holes provided on the control board, thereby electrically connecting the coils to the control board (and the control unit provided on the control board). In other words, in the motor unit of Patent Document 1, the terminals of the coil wires that constitute the coils function as power lines for the electric motor.

[0003] In the motor unit of Patent Document 1, to simplify the process of connecting the terminals of the coil wire to the control board, a resin coil guide is provided axially between the electric motor and the control board to guide the terminals of the coil wire axially toward a hole in the control board and hold them in a predetermined position and orientation. This coil guide functions as a partition wall that divides the interior space of the housing into an electric motor chamber and a control board chamber, and also functions as a lid member that seals an opening at one end of the motor chamber. To this end, the coil guide is provided with a guide portion consisting of an axial through hole that guides the terminals of the coil wire axially, a potting region provided in the region where the guide portion opens on one or the other end of the coil guide, and a potting material filled in the potting region.

[0004] With this configuration, after the coil wire (or its terminal portion) is inserted into the guide portion of the coil guide, the gap between the coil wire and the guide portion is sealed by the potting material filled in the potting area, thereby liquid-tightly separating the motor housing chamber and the board housing chamber. As a result, even if a fluid (insulating fluid) such as oil seeps into the motor housing chamber from the pump housing chamber that houses the pump unit, the insulating fluid is prevented from seeping into the board housing chamber via the guide portion (the gap) and from adhering to the control board, making it possible to stably maintain and exert a predetermined motor output, and ultimately pump capacity.

[0005] Japanese Patent Application Laid-Open No. 2023-4064

[0006] When a motor control board is disposed axially outside the electric motor, as in the motor unit of Patent Document 1, a member (coil guide) that functions as a partition and a cover member must be provided between the motor housing chamber and the board housing chamber in the axial direction, and the power line must be held accurately relative to this coil guide. However, due to the configuration of Patent Document 1, when holding the power line in the coil guide, it is necessary to precisely insert and position the terminal end of the coil wire into a guide portion consisting of an axial through-hole, and to fill and harden the potting material in the potting region, which tends to make the assembly process of the motor unit complicated and costly.

[0007] In view of the above circumstances, a main object of the present invention is to provide a motor unit that is easy to assemble.

[0008] The present invention, which was devised to achieve the above-mentioned object, is a motor unit comprising: an electric motor consisting of a three-phase motor; a control board arranged in a direction perpendicular to the axial direction of the electric motor; and a housing having a motor accommodating chamber that accommodates the electric motor, a board accommodating chamber that accommodates the control board, and a partition wall provided between the motor accommodating chamber and the board accommodating chamber, wherein the stator coil and the control board are electrically connected by inserting pin-shaped terminals extending in the axial direction that are connected to the stator coil of the electric motor into terminal insertion holes provided in the control board through terminal insertion holes provided in the partition wall, and wherein the pin-shaped terminals are held in the partition wall via a terminal holding portion that holds them insulated on its inner periphery and an annular elastic seal provided on the outer periphery of the terminal holding portion.

[0009] According to the above configuration, when assembling the motor unit, the opening of the motor chamber of the housing is sealed with a partition wall (dividing the interior space of the housing into a motor chamber and a circuit board chamber by the partition wall), if an annular elastic seal is provided on the outer periphery of the terminal holder that holds the pin terminals on its inner periphery, the terminal insertion holes in the partition wall can be sealed simply by inserting the pin terminals (held in the terminal holder that has the elastic seal attached to its outer periphery) into the terminal insertion holes in the partition wall, without having to fill the partition wall with potting material and harden the filled potting material. Furthermore, when the pin terminals held by the terminal holder are inserted into the terminal insertion holes in the partition wall and the opening of the motor chamber is sealed with the partition wall, the partition wall and the elastic seal allow the pin terminals to be positioned relative to the housing. Therefore, the insertion of the pin terminals into the terminal insertion holes in the circuit board, i.e., the electrical connection between the stator coil and the control board, can be completed smoothly. Therefore, the present invention provides a motor unit that is easy to assemble and can be mass-produced at low cost.

[0010] To realize a highly durable and reliable motor unit, it is preferable to use a metal housing, including the partition wall. In this case, it is preferable to hold the pin terminals in the partition wall (terminal insertion holes) with the board-accommodating-chamber-side end of the terminal holder protruding into the board-accommodating chamber. This allows for a longer creepage distance between the housing partition wall and the pin terminals compared to, for example, when the board-accommodating-chamber-side end of the terminal holder and the partition wall are flush with each other, thereby improving insulation between the housing partition wall and the pin terminals.

[0011] In order to properly seal between the pin-shaped terminal (the terminal holding portion holding the pin-shaped terminal) and the terminal insertion hole in the partition wall, an annular groove containing an elastic seal can be provided on the outer surface of the terminal holding portion.

[0012] The motor stator having the above configuration may further include three bus bars, each having the pin-shaped terminal and a terminal for connection to a corresponding stator coil, and a retaining member that insulates and holds the three bus bars in a non-contact state between the electric motor and the partition wall in the axial direction. In this case, the terminal retaining portion may be molded from resin integrally with the retaining member.

[0013] The partition wall may have a cylindrical bearing mounting surface on which a support bearing for the output shaft of the electric motor is mounted.

[0014] The housing may further include a pump chamber that accommodates a pump rotor that is attached to the output shaft of the electric motor, and the motor chamber and the pump chamber may be connected via a radial gap. In other words, the motor unit according to the present invention can be used as a motor unit for a fluid pump that sucks and pumps fluid such as oil, and because the motor chamber and the substrate chamber are separated liquid-tightly, infiltration of fluid into the substrate chamber can be prevented as much as possible, thereby maintaining and exhibiting the desired motor performance in a stable manner.

[0015] As described above, according to the present invention, a motor unit that is easy to assemble can be realized.

[0016] Fig. 2 is a longitudinal sectional view of an electric pump including a motor unit according to an embodiment of the present invention; Fig. 3 is a plan view of a motor cover (partition wall) of the motor unit shown in Fig. 1, as viewed from the direction of arrow A; Fig. 4 is a perspective view of a stator unit; Fig. 5 is an exploded perspective view of the motor unit; Fig. 6 is a partially enlarged view of Fig. 1; Fig. 7 is a partially enlarged view of a motor unit according to another embodiment of the present invention;

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 6).

[0018] FIG. 1 is a longitudinal cross-sectional view of an electric pump 1 including a motor unit 2 according to one embodiment of the present invention. The electric pump 1 shown in the figure is mounted on a vehicle such as an automobile and used as an electric oil pump that generates hydraulic pressure in a transmission while the engine is stopped. The electric pump 1 includes a motor unit 2, a pump unit 3 driven by the output of the motor unit 2, and a housing 5 that houses both units 2 and 3. The terms "axial direction," "radial direction," and "circumferential direction" used in the following description refer to a direction parallel to an axis O of an output shaft 12 of an electric motor 10 constituting the motor unit 2, a radial direction of a circle centered on the axis O, and a circumferential direction of the circle, respectively. The left side of the paper in FIG. 1 (the side where the motor unit 2 is located) and the opposite side (the side where the pump unit 3 is located) are also referred to as one axial side and the other axial side, respectively.

[0019] The housing 5 has a motor accommodating chamber 51 and a board accommodating chamber 52 that respectively accommodate the electric motor 10 and the control board 20 that are components of the motor unit 2, and a pump accommodating chamber 53 that accommodates the pump unit 3.

[0020] The motor accommodating chamber 51 is mainly formed by a cylindrical motor case 54 having the stator 15 of the electric motor 10 fixed to its inner peripheral surface and a motor cover 55 that seals the opening at one axial end of the motor case 54, while the board accommodating chamber 52 is formed by a cylindrical board case 56 attached to the outer periphery of the motor case 54, the motor cover 55, and a board cover 57 that seals the opening at one axial end of the board case 56. The pump accommodating chamber 53 is mainly formed by a cylindrical pump case 58 disposed adjacent to the other axial side of the motor case 54 and a pump cover 59 that seals the opening at the other axial end of the pump case 58. The components of the housing 5, such as the motor case 54 and the pump case 58, are made of a metal material that has good electrical and thermal conductivity and is easy to process, such as an aluminum alloy.

[0021] The motor housing chamber 51 and the pump housing chamber 53 communicate with each other via a radial gap Ga formed between the inner circumferential surface of the pump case 58 and the outer circumferential surface of the output shaft 12 of the electric motor 10, while the motor housing chamber 51 and the substrate housing chamber 52 are separated in a liquid-tight manner. A motor cover 55 is disposed between the motor housing chamber 51 and the substrate housing chamber 52, and this motor cover 55 (and various seals attached thereto; details will be described later) separates the two housing chambers 51, 52 in a liquid-tight manner. Therefore, the motor cover 55 also functions as a "partition wall" as defined in the present invention.

[0022] The pump unit 3 of this embodiment is a trochoid pump in which an inner rotor 4A is mounted on a portion of the output shaft 12 of the electric motor 10 that is positioned in the pump housing chamber 53 so as to be rotatable together with the inner rotor 4A, and an outer rotor 4B that meshes with the inner rotor 4A is positioned radially outward of the inner rotor 4A. In this type of pump, when the outer rotor 4B is driven to rotate as the inner rotor 4A rotates together with the output shaft 12 of the electric motor 10, oil is continuously sucked into a pump chamber formed between the inner rotor 4A and the outer rotor 4B and discharged (pressurized) to the outside of the pump chamber.

[0023] The motor unit 2 includes an electric motor 10 , a control board 20 arranged on one axial side of the electric motor 10 and provided with a control unit that controls the operation of the electric motor 10 , and a busbar unit 30 .

[0024] The control board 20 is a flat member with a mounting surface 20a, on which electronic components (not shown) are mounted, arranged along the radial direction, and is secured to the housing 5 with screws (screws are not shown) while housed in the board housing chamber 52 of the housing 5. Examples of electronic components mounted on the mounting surface 20a include capacitors such as electrolytic capacitors, inductors, semiconductor elements (switching elements) such as MOSFETs, integrated circuits such as driver ICs, and resistors. These electronic components are electrically connected to form a control unit that controls the operation of the electric motor 10.

[0025] The electric motor 10 is a radial gap type three-phase motor including a rotor 11 and a cylindrical stator 15 that is disposed radially outward of the rotor 11 at a distance and fixed to the inner circumferential surface of the housing 5 (motor case 54). Therefore, the stator 15 has U-phase, V-phase, and W-phase coils 17.

[0026] The rotor 11 has an output shaft 12 of the electric motor 10, and this output shaft 12 is rotatably supported in the housing 5 via two support bearings (a first rolling bearing 13A and a second rolling bearing 13B) arranged axially at an interval. The first rolling bearing 13A is mounted on a cylindrical bearing mounting surface 55a provided on the motor cover 55, and supports a portion of the output shaft 12 that protrudes to one axial side of the stator 15. The second rolling bearing 13B is mounted on the inner circumferential surface of an annular portion provided at the other axial end of the motor case 54, and supports a portion of the output shaft 12 that protrudes to the other axial side of the stator 15. The rolling bearings 13A and 13B are, for example, deep groove ball bearings.

[0027] The motor unit 2 of this embodiment is provided with a detection unit 6 for detecting the rotation angle of the rotor 11 (output shaft 12). The detection unit 6 includes a sensor magnet 6A attached to one axial end of the output shaft 12 via a bracket, and a rotation sensor 6B attached to the control board 20 and arranged axially opposite the sensor magnet 6A.

[0028] The rotation sensor 6B is electrically connected to a control unit provided on the control board 20, and the value detected by the rotation sensor 6B is input to the control unit. As a result, the value detected by the rotation sensor 6B is used to control the operation of the electric motor 10. Note that the detection unit 6 is not necessarily provided and may be omitted in some cases. In other words, the motor unit 2 (and the electric pump 1 including the motor unit 2) may be used in a sensorless state without the detection unit 6.

[0029] In the motor unit 2 of this embodiment, the stator 15 is accommodated and fixed in the motor accommodating chamber 51 of the housing 5 in an assembled state with the annular busbar unit 30 attached to one axial end of the stator 15 (see Figures 3 and 4).

[0030] The stator 15 includes a starter core 16 having a plurality of teeth 16a spaced apart in the circumferential direction, and a plurality of coils (stator coils) 17 formed by winding coil wire around the outer periphery of each tooth 16a with an insulating member such as an insulator interposed therebetween. As described above, the coils 17 include U-phase, V-phase, and W-phase coils, and the same number of coils 17 are provided for each phase. Each coil 17 is formed by so-called concentrated winding.

[0031] The busbar unit 30 includes a plurality of busbars 31 formed of a metal material with high electrical conductivity such as copper, and a holding member 33 formed of an insulating material such as resin, which holds the plurality of busbars 31 in an insulated, non-contact state.

[0032] There are provided at least three bus bars 31: a U-phase bus bar 31U having a connection terminal to which an end of the coil wire constituting the U-phase coil is connected, a V-phase bus bar 31V having a connection terminal to which an end of the coil wire constituting the V-phase coil is connected, and a W-phase bus bar 31W having a connection terminal to which an end of the coil wire constituting the W-phase coil is connected. When the connection method of the coils 17 is a delta connection, one bus bar 31 is provided for each phase, and when the connection method of the coils 17 is a star connection, in addition to the bus bars 31 for each phase, a neutral bus bar is provided.

[0033] Each of U-phase bus bar 31U, V-phase bus bar 31V, and W-phase bus bar 31W is provided with a pin-shaped terminal 32 extending along the axial direction. In the completed motor unit 2 (see FIG. 1 ), (the tip of) each pin-shaped terminal 32 is inserted into a corresponding terminal insertion hole 21 provided in control board 20. This electrically connects coil 17 and control board 20 (a control unit provided thereon), enabling a current for driving the motor to be supplied to coil 17.

[0034] The retaining member 33 that holds the bus bars 31 has an annular portion 34 that is arranged coaxially with the stator core 16 on one axial side of the stator core 16, and a cylindrical terminal retaining portion 35 that holds the pin-shaped terminals 32 of each bus bar 31 in a state of not contacting the partition wall (motor cover 55) of the housing 5 made of a conductive metal, and the annular portion 34 and the terminal retaining portion 35 are formed integrally or separately from an insulating resin material. The retaining member 33 is attached to the stator core 16 by any appropriate means (for example, snap fitting) that allows a predetermined amount of relative movement with respect to the stator 15 (stator core 16) in the axial, radial, and circumferential directions.

[0035] Terminal insertion holes 21 are formed on both the front and back surfaces (mounting surface 20a and the surface opposite thereto) of control board 20. The terminal insertion holes 21 are holes into which (the tips of) pin-shaped terminals 32 of bus bars 31 are inserted, and a total of three terminal insertion holes 21 are provided at intervals corresponding to the radial and circumferential arrangement positions of pin-shaped terminals 32 of U-phase bus bar 31U, V-phase bus bar 31V, and W-phase bus bar 31W.

[0036] The motor cover 55 is provided with three spaced-apart terminal insertion holes 55b, each consisting of an axial through-hole. A resin terminal holder 35, which holds a pin terminal 32 of a bus bar 31 (31U, 31V, 31W), is individually inserted into each terminal insertion hole 55b with a clearance fit. As shown enlarged in FIG. 5 , a radial gap Gb exists between the outer circumferential surfaces of the opposing terminal holders 35 and the inner circumferential wall surface of the terminal insertion hole 55b. The term "clearance fit" used here conforms to the definition of "clearance fit" specified in JIS B 0401-2. An annular elastic seal 37 is disposed in the radial gap Gb, elastically compressed and deformed in the radial direction, i.e., pressed against both the outer circumferential surface of the terminal holder 35 and the inner circumferential wall surface of the opposing terminal insertion hole 55b.

[0037] As described above, the motor unit 2 of this embodiment constitutes a part of the electric pump (electric oil pump) 1, and the motor accommodating chamber 51, which accommodates the motor unit 2 within the internal space of the housing 5, communicates with the pump accommodating chamber 53, which contains oil as an insulating fluid, via a minute radial gap Ga. As a result, oil is also present within the motor accommodating chamber 51. If this oil flows into the board accommodating chamber 52 and adheres to electronic components mounted on the control board 20, there is a risk that the control unit will not operate normally.

[0038] Therefore, in the housing 5, an annular elastic seal 36 that functions as an oil seal is interposed in an elastically compressed and deformed state in the mating portion of the motor case 54 and the motor cover 55 (between the opposing inner surface of the motor case 54 and the outer surface of the motor cover 55), and as described above, an annular elastic seal 37 that functions as an oil seal is also interposed in an elastically compressed and deformed state in the radial gap Gb between the inner wall surface of the terminal insertion hole 55b of the motor cover 55 and the outer surface of the terminal holding portion 35 that faces it.

[0039] The elastic seals 36, 37 can be, for example, O-rings, but liquid gaskets or grommets (sealing members with a shape appropriate for the application) can also be used instead of O-rings. The elastic seals 36, 37 can be made of resin, but rubber is preferred because it is flexible, easily elastically deformed, and can absorb gap variations due to dimensional tolerances of parts and components. The rubber material used to form the elastic seals 36, 37 can be changed as appropriate depending on the type of fluid present in the motor housing chamber 51. In this embodiment, in which oil is present in the motor housing chamber 51, oil-resistant materials such as acrylic rubber, nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), and silicone rubber are preferred.

[0040] In this embodiment, the motor cover 55 has an axial center hole on its inner periphery, in which the end of the output shaft 12 (and the sensor magnet 6A) are disposed. The opening of this center hole is closed by a concave-shaped cover member that fits onto the inner periphery of the center hole. This configuration minimizes the intrusion of oil into the circuit board housing space 52.

[0041] The motor unit 2 having the above configuration is assembled, for example, by following the steps (1) to (4) below (also see FIG. 4).

[0042] [Step 1] An assembly including the stator 15 and the busbar unit 30 is inserted into the motor case 54 (the motor housing chamber 51 defined on the inner periphery of the motor case 54) having the circuit board case 56 fixed to the outer periphery, and the stator 15 is fixed to the inner periphery of the motor case 54.

[0043] [Step 2] An assembly with the first rolling bearing 13A mounted on the outer periphery of the output shaft 12 is inserted into the inner periphery of the stator 15, and the second rolling bearing 13B mounted on the inner periphery of the motor case 54 is mounted on the outer periphery of the output shaft 12.

[0044] [Step 3] After the elastic seal 36 is attached to the motor cover 55 (in the annular groove on the outer surface thereof) and the elastic seals 37 are attached to the outer peripheries of the three terminal holders 35, the motor cover 55 is fitted to the inner periphery of one axial end of the motor case 54. In this embodiment, as shown in FIG. 5 , the elastic seal 37 is attached so as to axially engage with the radially stepped surface 35a on the outer periphery of the terminal holder 35. When fitting the motor cover 55 to the motor case 54, the terminal holders 35, which hold the terminals 32 of the bus bars 31 on their inner peripheries and the elastic seals 37 on their outer peripheries, are fitted into each of the three terminal insertion holes 55b provided in the motor cover 55, and the elastic seals 37 are pressed against both the outer periphery of the terminal holders 35 and the inner periphery of the terminal insertion holes 55b facing each other. This positions each terminal 32 in the radial and circumferential directions.

[0045] [Step 4] The control board 20 is placed in the board accommodating chamber 52, and the control board 20 is screwed to the housing 5. When placing the control board 20 in the board accommodating chamber 52, the terminals 32 of each bus bar 31 are inserted into the corresponding terminal insertion holes 21. After fixing the control board 20 to the housing 5 in this manner, the board cover 57 is fixed to the board case 56 so as to close the end opening on one axial side of the board case 56.

[0046] In the motor unit 2 of this embodiment described above, the coil 17 of the electric motor 10 is electrically connected to the control board 20 (its control unit) by inserting the pin-shaped terminal 32 of the bus bar 31, which is wired to the coil 17 of the electric motor 10, into the terminal insertion hole 21 provided in the control board 20 through the terminal insertion hole 55b provided in the motor cover 55, which functions as a partition wall. The pin-shaped terminal 32 is held in the motor cover 55 via the terminal holding portion 35, which holds the pin-shaped terminal 32 insulated on its inner periphery, and the annular elastic seal 37 provided on the outer periphery of the terminal holding portion 35.

[0047] According to this configuration, when assembling the motor unit 2, the opening of the motor accommodating chamber 51 is sealed with the motor cover 55 (the internal space of the housing 5 is divided into the motor accommodating chamber 31 and the board accommodating chamber 32 by the motor cover 55), if an annular elastic seal 37 is provided on the outer periphery of the terminal holding portion 35 which holds the pin-shaped terminal 32 insulatedly on its inner periphery, the terminal insertion hole 55b can be sealed simply by inserting the pin-shaped terminal 32 (the pin-shaped terminal 32 held by the terminal holding portion 35 which has the elastic seal 37 attached to its outer periphery) into the terminal insertion hole 55b of the motor cover 55.

[0048] Furthermore, when the pin-shaped terminal 32 held by the terminal holding portion 35 is inserted into the terminal insertion hole 55b and one end opening of the motor accommodating chamber 51 (motor case 54) is sealed with the motor cover 55, the motor cover 55 and the elastic seal 37 allow the pin-shaped terminal 32 held by the terminal holding portion 35 to be positioned relative to the housing 5 (the assembly of the motor case 54 and the board case 56).

[0049] In particular, in this embodiment, because the motor cover 55 is made of metal, the dimensional tolerances of each part can be set smaller than those of the resin coil guides used in conventional motor units. This allows the pin terminals 32 and the terminal insertion holes 21 of the control board 20 to be positioned with high radial and circumferential precision. This allows the insertion of the pin terminals 32 into the terminal insertion holes 21 of the board 20 (electrical connection between the coil 17 and the control board 20), which is required when attaching the control board 20 to the housing 5, to be completed smoothly and accurately.

[0050] Furthermore, as described above, if the pin-shaped terminals 32 of each bus bar 31 are positioned radially and circumferentially by the motor cover 55, the stator 15 (stator core 16), to which the bus bar unit 30 is attached, is less likely to affect the positional accuracy of the terminals 32 of the bus bars 31. This makes it possible to relax the fixing accuracy of the bus bar unit 30 relative to the stator 15 and the dimensional accuracy (dimensional tolerance) required of the stator core 16.

[0051] As described above, the motor unit 2 (and the electric pump 1 including the motor unit 2) according to this embodiment has the advantages of being easy to assemble and being inexpensive to manufacture.

[0052] To achieve a highly durable and reliable motor unit 2 (electric pump 1), the housing 5 of the motor unit 2 of this embodiment is made of metal (particularly, aluminum alloy, which has high conductivity), including the motor cover 55, which also functions as a partition wall. While insulation of the pin terminals 32 from the metal motor cover 55 is ensured by the resin terminal holder 35 and the elastic seal 37 attached to its outer periphery, it is desirable to increase the insulation between the motor cover 55 and the pin terminals 32 as much as possible to stably maintain and achieve the desired motor performance. Therefore, the terminal holder 35, which holds the pin terminals 32, is held by the motor cover 55 with its end on the circuit board accommodating chamber 32 side (one axial side) protruding into the circuit board accommodating chamber 32, as shown enlarged in FIG. 5 . This allows the surface distance between the motor cover 55 and the pin-shaped terminals 32 to be longer than when the terminal holding portion 35 and the end of the motor cover 55 on the board accommodating chamber 52 side are flush, thereby improving the insulation between the motor cover 55 and the pin-shaped terminals 32.

[0053] The motor unit 2 and the electric pump 1 including the motor unit 2 according to one embodiment of the present invention have been described above, but the present invention is not limited to this embodiment.

[0054] 6, an annular groove 35b containing an elastic seal 37 may be provided on the outer peripheral surface of the terminal holder 53. In this way, the radial gap Gb formed between the terminal holder 53 holding the pin terminal 32 and the terminal insertion hole 55b of the motor cover 55 can be appropriately sealed, thereby improving the liquid-tightness of the motor accommodating chamber 51.

[0055] The present invention is not limited to the above-described embodiment, and can be embodied in various other forms without departing from the spirit of the present invention.

[0056] REFERENCE SIGNS LIST 1 electric pump 2 motor unit 3 pump unit 5 housing 10 electric motor 12 output shaft 15 stator 17 coil (stator coil) 20 control board 21 terminal insertion hole 30 bus bar unit 31 bus bar 32 pin-shaped terminal 35 terminal holding portion 37 elastic seal 51 motor accommodating chamber 52 board accommodating chamber 53 pump accommodating chamber 54 motor case 55 motor cover (partition wall) 55a bearing mounting surface 55b terminal insertion hole

Claims

1. A motor unit comprising: an electric motor consisting of a three-phase motor; a control board arranged in a direction perpendicular to the axial direction of the electric motor; and a housing having a motor accommodation chamber that accommodates the electric motor, a board accommodation chamber that accommodates the control board, and a partition wall provided between the motor accommodation chamber and the board accommodation chamber, wherein the stator coil and the control board are electrically connected by inserting pin-shaped terminals that extend in the axial direction and are connected to the stator coil of the electric motor into terminal insertion holes provided in the control board via terminal insertion holes provided in the partition wall, and wherein the pin-shaped terminals are held by the partition wall via a terminal holding section that holds the pin-shaped terminals insulated on the inner periphery and an annular elastic seal provided on the outer periphery of the terminal holding section.

2. A motor unit as described in claim 1, wherein the housing including the partition is formed of metal, and the pin-shaped terminals are held by the partition with the ends of the terminal holding portions on the board accommodating chamber side protruding into the board accommodating chamber.

3. The motor unit according to claim 1, wherein an annular groove is provided on the outer peripheral surface of said terminal holding portion to accommodate said elastic seal.

4. A motor unit as described in claim 1, further comprising a total of three bus bars, each having a terminal for connection to the pin-shaped terminal and the corresponding end portion of the stator coil, and a retaining member that insulates and holds the total of three bus bars in a non-contact state between the electric motor and the partition wall in the axial direction, wherein the terminal retaining portion is molded from resin integrally with the retaining member.

5. The motor unit according to claim 1, wherein the partition wall has a cylindrical bearing mounting surface on which a support bearing for the output shaft of the electric motor is mounted.

6. A motor unit as described in claim 1, wherein the housing further has a pump accommodating chamber that accommodates a pump rotor attached to the output shaft of the electric motor, and the motor accommodating chamber and the pump accommodating chamber are connected via a radial gap.

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