CN113228478A

CN113228478A - Motor unit

Info

Publication number: CN113228478A
Application number: CN202080007205.6A
Authority: CN
Inventors: 山口雄平; 青野真乡; 佐藤留介
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2019-02-13
Filing date: 2020-02-07
Publication date: 2021-08-06
Also published as: WO2020166532A1

Abstract

One embodiment of a motor unit according to the present invention includes: a motor main body having a rotor that rotates about a central axis extending in a vertical direction and a stator located radially outward of the rotor; a one-way clutch having an inner ring and an outer ring, the inner ring being coupled to the rotor; a housing that houses the motor main body; and a holding member fixed to the housing and coupled to the outer ring, the holding member being made of the same material as the outer ring.

Description

Motor unit

Technical Field

The present invention relates to a motor unit.

The application is based on Japanese patent application No. 2019-023886 filed on 13.2.2019. The benefit of priority is claimed by this application. The contents of which are incorporated by reference into this application in their entirety.

Background

In a motor having a rotor and a stator, a shaft of the rotor is rotatably supported by a bearing. The motor transmits the rotation of the shaft to the outside, thereby driving a device or the like to be driven. Such a motor may be provided with a one-way clutch to suppress reverse rotation of the shaft. For example, patent document 1 discloses a structure in which a one-way clutch is provided between a shaft (output shaft) and a pump cover of an oil pump to be driven.

Patent document 1: international publication No. 2013/099505

Disclosure of Invention

Problems to be solved by the invention

Such a motor is sometimes used for an oil pump for raising the oil temperature from room temperature to about 150 ℃. As a material of the one-way clutch, iron-based alloys (steel) similar to those of a bearing and the like are mainly used. On the other hand, aluminum alloys are often used for a case such as a pump cover supporting the one-way clutch for weight reduction. The difference in linear expansion coefficient between the iron-based alloy and the aluminum alloy is large. Therefore, a gap may be enlarged between the housing and the one-way clutch to generate a lost motion.

In view of the above, an object of the present invention is to provide a motor unit capable of improving the reliability of the connection between the one-way clutch and the housing.

Means for solving the problems

Effects of the invention

According to one aspect of the present invention, a motor unit capable of improving the reliability of the connection between the one-way clutch and the housing is provided.

Drawings

Fig. 1 is a perspective view showing an external appearance of a motor unit according to an embodiment.

Fig. 2 is a plan view of the motor unit according to the embodiment as viewed from above.

Fig. 3 is a view showing an internal structure of a motor unit according to an embodiment, and is a sectional view taken along line III-III of fig. 2.

Fig. 4 is a view showing an internal structure of a lower portion of the motor unit according to the embodiment, and is an enlarged view of a main portion of fig. 3.

Fig. 5 is an expanded perspective view of a housing of the motor unit of one embodiment.

Detailed Description

Fig. 1 is a perspective view showing an external appearance of a motor unit 10 of the present embodiment. Fig. 2 is a plan view of the motor unit 10 of the present embodiment as viewed from above. Fig. 3 is a diagram showing the internal structure of the motor unit 10 of the present embodiment, and is a cross-sectional view taken along the line III-III in fig. 2. As shown in fig. 1 to 3, the motor unit 10 includes a motor main body 20, a housing 11, a control unit 50 (see fig. 3), and an upper cover 60.

In the following description, a direction parallel to the central axis J (see fig. 3) is simply referred to as an "axial direction" or a "vertical direction", a radial direction about the central axis J is simply referred to as a "radial direction", and a circumferential direction about the central axis J, that is, a direction around the central axis J is simply referred to as a "circumferential direction". In the following description, the term "plan view" refers to a state viewed in the axial direction. In the present specification, the upper side of fig. 3 in the axial direction along the center axis J is simply referred to as "upper side", and the lower side is simply referred to as "lower side". The "vertical direction" does not indicate the posture, positional relationship and direction of each part of the motor unit 10 when the motor unit is mounted on an actual device. In the drawings below, the actual structure may be different from the structure in scale, number, or the like in order to facilitate understanding of the structures.

As shown in fig. 3, the motor main body 20 has a rotor 25 and a stator 21. The rotor 25 rotates about a central axis J extending in the vertical direction. The rotor 25 has a shaft 26, a rotor core 27, and a plurality of magnets 28.

The shaft 26 is disposed along a central axis J extending in the vertical direction. The shaft 26 has a cylindrical shape extending in the vertical direction. The shaft 26 is made of metal and is made of an iron-based alloy (steel material). The shaft 26 is supported by an upper bearing 29A and a lower bearing 29B so as to be rotatable about the center axis J. An upper bearing 29A supporting the upper portion of the shaft 26 is held by a motor housing 30 of the housing 11. The upper bearing 29A is located on the upper side of the stator 21. The lower bearing 29B supporting the lower portion of the shaft 26 is held by the gear housing 40. The lower bearing 29B is located on the lower side of the stator 21. In the present embodiment, the lower bearing 29B is constituted by the one-way clutch 89, as will be described later in detail.

As shown in fig. 3, rotor core 27 is columnar extending in the vertical direction. The rotor core 27 has a fixing hole portion 27a penetrating the rotor core 27 in the vertical direction. The shape of the fixing hole portion 27a as viewed in the up-down direction is a circle centered on the central axis J. The shaft 26 passes through the fixing hole portion 27 a. The shaft 26 is fixed to the rotor core 27 by press fitting, bonding, or the like. The shaft 26 may be fixed to the rotor core 27 via a resin member or the like. Thereby, the rotor core 27 is fixed to the shaft 26.

The plurality of magnets 28 are fixed to the rotor core 27. The magnet 28 may be fixed inside the rotor core 27 or may be fixed to the outer peripheral surface. The plurality of magnets 28 are arranged in the circumferential direction. The magnets 28 adjacent to each other in the circumferential direction are arranged such that magnetic poles facing the radial direction are reversed from each other. The plurality of magnets 28 are arranged at equal intervals in the circumferential direction over the entire circumference.

The stator 21 is located radially outside the rotor 25. The stator 21 mainly has a stator core 22 and a coil 24.

Stator core 22 includes a cylindrical core back portion 23a centered on central axis J, and a plurality of tooth portions 23b extending radially inward from core back portion 23 a. As shown in fig. 1, the core back 23a has a core outer peripheral surface 22a facing radially outward. The core outer peripheral surface 22a extends in the circumferential direction. As described later, the core outer peripheral surface 22a of the core back 23a is exposed from the motor case 30.

The plurality of teeth 23b are provided at equal intervals in the circumferential direction around the center axis J. The coil 24 is wound around the tooth portion 23b with an insulating insulator interposed therebetween.

The housing 11 has a motor housing (first member) 30 and a gear housing (second member) 40. The motor case 30 houses the motor main body 20. Thereby, the housing 11 houses the motor main body 20. The gear housing 40 houses a drive gear not shown. In the present specification, "containing" is a concept including not only a case where the entire object enters the inside but also a case where at least a part of the object is surrounded by the object.

The motor housing 30 includes a motor holding portion 32, a bearing holder 33, and a washer 34.

The motor holding portion 32 is made of resin. More specifically, the insert molded product includes the stator 21, the bearing holder 33, and the washer 34. In other words, the motor holding portion 32 is a resin portion 32p that holds the stator 21, the bearing holder 33, and the washer 34. As shown in fig. 1 to 3, the motor holding portion 32 includes a columnar portion 35, a bulging portion 36, and a case expanding portion 37. The columnar portion 35, the bulging portion 36, and the case expanding portion 37 are one member.

The columnar portion 35 has a columnar shape extending in the vertical direction. The columnar portion 35 has substantially the same outer diameter as the stator 21. As shown in fig. 1, on the outer peripheral surface of columnar portion 35, core outer peripheral surface 22a located at the outer peripheral portion of stator 21 may be exposed. As shown in fig. 3, the columnar portion 35 has a plate-like portion 35a and a filling portion 35 b. That is, the motor housing 30 has a plate-shaped portion 35a and a filling portion 35 b.

The plate-like portion 35a is provided above the stator 21. The plate-like portion 35a is a disc-like portion perpendicular to the central axis J. As shown in fig. 3, a bearing holding recess 35h is provided on the lower surface of the plate-like portion 35 a. The bearing holding recess 35h is located at the center of the plate-like portion 35 a. The bearing holding recess 35h is recessed upward. The bearing holder 33 is held in the bearing holding recess 35 h. The plate-like portion 35a holds the upper bearing 29A via the bearing holder 33.

As shown in fig. 3, the bearing holder 33 is provided in the bearing holding recess 35h of the motor holding portion 32. The bearing holder 33 is made of metal. The bearing holder 33 has a holder cylinder portion 33a and a cover portion 33 b. The cage cylinder portion 33a and the cover portion 33b are one member. The holder cylinder portion 33a is cylindrical and extends in the vertical direction. The upper bearing 29A is disposed radially inward of the holder cylindrical portion 33 a. The lid portion 33b is a portion that is shaped like a circular plate extending so as to intersect the vertical direction and covers the upper end portion of the holder cylinder portion 33 a.

The filling portion 35b surrounds the teeth 23b and the coils 24 in the stator 21, and is provided between the teeth 23b and the coils 24 adjacent to each other in the circumferential direction.

The filling portion 35b extends downward from the plate-like portion 35 a.

As shown in fig. 1 to 3, the bulging portion 36 is provided on the outer peripheral portion of the columnar portion 35. The bulging portion 36 protrudes radially outward from the outer peripheral surface of the columnar portion 35. The bulging portions 36 are provided at a plurality of positions at intervals in the circumferential direction. In the present embodiment, the bulging portions 36 are provided at 3 in the circumferential direction at intervals. As shown in fig. 3, the respective bulging portions 36 are continuous in the vertical direction. Each of the bulging portions 36 has a hole portion 36h extending in the vertical direction. That is, resin portion 32p is provided with hole portion 36 h.

As shown in fig. 1 and 2, the case expanding portion 37 is provided on an outer peripheral portion of an upper portion of the motor holding portion 32 (more specifically, the columnar portion 35). The case expanding portion 37 is provided only in a part in the vertical direction with respect to the columnar portion 35. The case expanding portion 37 is provided between two bulging portions 36 adjacent to each other in the circumferential direction. The case expanding portion 37 extends radially outward from the upper portion of the columnar portion 35.

As shown in fig. 3, the washer 34 is disposed in the hole 36h of the bulging portion 36. The gasket 34 is made of metal and has a cylindrical shape extending in the vertical direction. The washer 34 is provided with a bolt insertion hole 34h penetrating in the vertical direction. The gasket 34 is molded into the bulge 36. The washer 34 is exposed on the upper surface 36a and the lower surface 36b of the bulge portion 36. The length of the gasket 34 in the vertical direction is slightly larger than the thickness of the bulging portion 36 in the vertical direction (the vertical distance between the upper surface 36a and the lower surface 36 b). The upper end portion of the washer 34 protrudes upward with respect to the upper surface 36a of the bulge portion 36. The lower end portion of the washer 34 protrudes downward with respect to the lower surface 36b of the bulging portion 36. When a bolt 70 described later is tightened, the upper cover 60 and the gear housing 40 abut against the upper and lower sides of the washer 34, and an excessive axial force of the bolt 70 is suppressed from acting on the motor holding portion 32 made of resin.

Fig. 4 is a diagram showing an internal structure of a lower portion of the motor unit 10 of the present embodiment, and is an enlarged view of a main portion of fig. 3. Fig. 5 is an expanded perspective view of the housing 11 of the motor unit 10 of the present embodiment. As shown in fig. 4 and 5, the gear housing 40 is provided on the lower side of the motor housing 30. The gear housing 40 has a base portion (outer ring holding portion) 41 and an outer cylinder portion 42. The base 41 and the outer cylindrical portion 42 are one member. The gear housing 40 is made of metal and is made of aluminum alloy.

The base portion 41 is a disk-shaped portion intersecting the vertical direction. The central portion of the base 41 is provided with a bearing holding hole 43. The bearing holding hole 43 penetrates the base portion 41 in the vertical direction. The upper portion 43a of the bearing holding hole 43 has an enlarged inner diameter with respect to the lower portion 43 b. The inner circumferential surface of the upper portion 43a of the bearing holding hole 43 is provided with a housing recess 43d that is enlarged radially outward from the inner circumferential surface of the lower portion 43 b. The housing recess 43d is a space portion opened upward.

The outer tube portion 42 is a cylindrical shape extending in the vertical direction, and extends downward in the vertical direction from the outer peripheral portion of the base portion 41. As shown in fig. 4, a gear housing recess 44 is provided radially inward of the outer tube portion 42. The gear housing recess 44 opens downward of the gear housing 40.

As shown in fig. 4 and 5, the upper surface of the gear housing 40 is provided with a plurality of screw holes 46. Each screw hole 46 vertically faces a bolt insertion hole 34h of the washer 34 provided in the bulging portion 36 of the motor case 30. The inner peripheral surface of each screw hole 46 is provided with an internal thread groove.

The gear housing 40 is provided with a holding member 90 on the upper side of the base portion 41. The holding member 90 holds the one-way clutch 89 constituting the lower bearing 29B. One-way clutch 89 has an outer race 81, an inner race 82, a plurality of steel balls 83, and a clutch portion 84. The outer race 81, the inner race 82, the steel balls 83, and the clutch portion 84 are made of metal and are made of iron-based alloy (steel material).

The inner ring 82 is cylindrical and extends in the vertical direction. The shaft 26 is pressed into the radially inner side of the inner race 82. Thereby, the inner race 82 is coupled to the rotor 25. The outer ring 81 is disposed radially outward of the inner ring 82 with a gap therebetween. The outer ring 81 is cylindrical and extends in the vertical direction. The plurality of steel balls 83 are disposed between the outer circumferential surface of the inner ring 82 and the inner circumferential surface of the outer ring 81. In the present embodiment, a one-way clutch 89 having a ball bearing mechanism using steel balls 83 as rolling elements is shown. However, the one-way clutch may have a needle bearing mechanism having a cylindrical body as a rolling body, or may have a structure without any bearing mechanism, that is, a structure having only the one-way clutch function.

The clutch portion 84 is disposed between the outer peripheral surface of the inner race 82 and the inner peripheral surface of the outer race 81 above the steel balls 83. When the shaft 26 rotates in a predetermined first direction around the shaft during operation of the motor main body 20, the clutch portion 84 slides between the inner race 82 and the outer race 81 into which the shaft 26 is press-fitted. Thereby, the inner ring 82 is rotatable with respect to the outer ring 81, and the shaft 26 is rotatable around the axis. In this state, the one-way clutch 89 (the lower bearing 29B) functions as a bearing in the same manner as a normal bearing. When an external force for rotating the shaft 26 in the reverse direction in the second direction opposite to the predetermined first direction is input from the drive gear side, which is not shown, the clutch portion 84 increases the frictional resistance between the inner ring 82 and the outer ring 81. Thereby, the inner ring 82 is locked with respect to the outer ring 81, and the rotation of the inner ring 82 around the shaft is restricted. In this state, the one-way clutch 89 prevents an external force to rotate the shaft 26 in the reverse direction from being input from the driving gear side.

As shown in fig. 4 and 5, the holding member 90 includes a cylindrical portion 91 and a flange portion 92. The cylindrical portion 91 and the flange portion 92 are one member.

The cylindrical portion 91 is cylindrical and extends in the vertical direction. The cylindrical portion 91 is inserted radially inward of the housing recess 43d of the bearing holding hole 43. The cylindrical portion 91 is accommodated in the accommodation recess 43 d. The outer race 81 of the one-way clutch 89 is press-fitted into the radial inner side of the cylindrical portion 91. Thus, the holding member 90 has a cylindrical portion 91 into which the outer ring 81 is press-fitted. The holding member 90 is coupled to the outer race 81.

The flange 92 extends radially outward from the upper end of the cylindrical portion 91. The flange portion 92 is along the upper surface 41f of the base portion 41. The upper surface 41f is a plane perpendicular to the central axis J. That is, the flange portion 92 extends along a plane perpendicular to the center axis J. The flange portion 92 is sandwiched between the motor holding portion 32 of the motor housing 30 and the gear housing 40. Thereby, the holding member 90 is fixed to the housing 11. That is, the housing 11 includes the motor housing 30 and the gear housing 40 that hold the holding member 90 by sandwiching the flange portion 92 from the vertical direction.

The flange portion 92 has extended flange portions 93 at a plurality of positions in the circumferential direction. The extending flange portions 93 extend radially outward from the flange portions 92. The extended flange portion 93 is sandwiched between the bulging portion 36 of the motor housing 30 and the outer peripheral portion of the base portion 41 of the gear housing 40. More specifically, the extended flange portion 93 is sandwiched between the washer 34 and the outer peripheral portion of the base portion 41 of the gear housing 40. When the bolt 70 is fastened, the upper surface of each extended flange portion 93 contacts the lower surface of the washer 34, and the lower surface of each extended flange portion 93 contacts the upper surface of the outer peripheral portion of the base portion 41. Each extended flange portion 93 has a bolt insertion hole 94. The bolt insertion hole 94 extends through the flange 93 in the vertical direction. The bolt insertion holes 94 communicate with the bolt insertion holes 34h of the washer 34 provided in the bulging portion 36 in the vertical direction. A bolt 70 described later is inserted into the bolt insertion hole 94.

The holding member 90 is made of a material having a linear expansion coefficient closer to the outer ring 81 made of an iron-based alloy than the base portion 41 of the gear housing 40 made of an aluminum alloy. The holding member 90 is made of the same material as the outer race 81 of the one-way clutch 89. The holding member 90 is made of the same iron-based alloy (steel material) as the outer ring 81. The base portion 41 made of an aluminum alloy is made of a material different from that of the outer ring 81 made of an iron-based alloy. The holding member 90 is formed into a predetermined shape by press working.

As shown in fig. 3, the control portion 50 is located on the upper side of the motor main body 20. The control unit 50 controls the rotation of the rotor 25. The control unit 50 includes a control board 51. The control board 51 is flat and disposed above the plate-shaped portion 35a of the motor case 30 with a space therebetween. The control board 51 is provided in parallel with the upper surface of the plate-like portion 35 a. A plurality of electronic components are mounted on the upper and lower surfaces of the control board 51.

As shown in fig. 2, the control board 51 has a main body portion 51a and an expansion portion 51 b. The main body portion 51a and the expanding portion 51b are one member. The main body 51a is provided above the columnar portion 35 of the motor holding portion 32 of the motor case 30. Thereby, the motor body 20 and the bearing holder 33 face the control unit 50 in the vertical direction. The expanding portion 51b extends radially outward from the main body portion 51 a. The expanded portion 51b protrudes radially outward from the columnar portion 35 of the motor housing 30. The expanding portion 51b is disposed in a region overlapping the case expanding portion 37 when viewed in the vertical direction.

As shown in fig. 3, the expansion portion 51b of the control portion 50 is provided with a connector portion 53 extending downward. As shown in fig. 1 and 3, at least a part of the connector portion 53 protrudes downward from the housing extension portion 37. An external connector (not shown) for supplying power from the outside and inputting and outputting a control signal is detachably connected to the connector portion 53.

As shown in fig. 1 to 3, the upper cover 60 faces the motor case 30 in the vertical direction. The upper cover 60 covers the upper side of the motor housing 30. The upper cover 60 has a cover base 61 and a cover fixing portion 62. The cover base 61 and the cover fixing portion 62 are one member. The upper cover 60 is made of metal.

The cover base 61 covers the main body 51a and the expanding portion 51b of the control unit 50 from above. The cover base portion 61 is flat and perpendicular to the center axis J, and covers the upper portions of the column portion 35 and the case expanding portion 37 of the motor case 30. A protruding cover portion 61b protruding upward is provided in a part of the cover base portion 61. In order to avoid interference with the upper cover 60, electronic components having a large protruding dimension upward from the control board 51, wiring, and the like among the electronic components provided in the control unit 50 are provided below the protruding cover portion 61 b.

The cover fixing portions 62 are provided at a plurality of positions spaced apart in the circumferential direction in the outer peripheral portion of the cover base portion 61. The cover fixing portion 62 protrudes radially outward from the cover base portion 61. The cover fixing portion 62 is vertically opposed to the bulging portion 36 of the motor case 30.

As shown in fig. 3, the upper surface of the cover fixing portion 62 is located lower than the upper surface of the cover base portion 61. The cover fixing portion 62 is provided with a fixing hole 64 penetrating the upper cover 60 in the vertical direction. The fixing hole 64 vertically overlaps with the bolt insertion hole 34h of the washer 34 provided in the bulging portion 36 and the bolt insertion hole 94 of the holding member 90 when viewed from the vertical direction.

The upper cover 60 is fixed to the motor housing 30 by bolts 70. The shaft portion 71 of the bolt 70 is fastened to the screw hole 46 of the gear housing 40 through the bolt insertion hole 34h of the washer 34 and the bolt insertion hole 94 of the holding member 90 from the fixing hole 64 provided in the plurality of cover fixing portions 62. The axial force of the bolt 70 is transmitted between the cover fixing portion 62 of the metal upper cover 60 and the metal gear housing 40 via the metal washer 34. This suppresses an excessive axial force of the bolt 70 from acting on the bolt insertion hole 34 h.

In a state where the bolt 70 is fastened, the head 72 of the bolt 70 contacts the upper surface of the cover fixing portion 62 of the upper cover 60. In this state, the upper end surface 72t of the head 72 of the bolt 70 is positioned lower than the uppermost surface 61t of the cover base 61 of the upper cover 60. In the present embodiment, the uppermost surface 61t of the cover base 61 is the upper surface of the protruding cover portion 61 b.

Here, the upper cover 60 is in contact with the motor housing 30 and is directly fixed to the motor housing 30. Specifically, the upper surface of the motor housing 30 and the lower surface of the upper cover 60 directly contact each other in the vertical direction outside the control unit 50.

The motor unit 10 has a seal structure 80 that suppresses the intrusion of moisture from between the motor housing 30 and the upper cover 60. The seal structure 80 is provided along an inner peripheral edge portion of a region where the upper surface of the motor housing 30 and the lower surface of the upper cover 60 face each other in the up-down direction. The seal structure 80 is annularly provided so as to surround the entire circumference of the control unit 50 when viewed in the vertical direction. The plurality of bolts 70 are disposed outside the seal structure 80 when viewed in the vertical direction. The seal structure 80 is constituted by a gasket member formed in advance into a predetermined shape and a cured liquid gasket.

In the present embodiment, the holding member 90 coupled to the outer ring 81 is made of the same material as the outer ring 81. Since the outer ring 81 and the holding member 90 are made of the same material, the difference between the linear expansion coefficient of the outer ring 81 and the linear expansion coefficient of the holding member 90 can be reduced. This makes it possible to bring the volume change amount of the holding member 90 and the outer ring 81 close to each other when the temperature of the use environment of the motor unit 10 is increased or the processing is performed. Therefore, the gap between the holding member 90 and the outer ring 81 can be suppressed from expanding. As a result, according to the present embodiment, the backlash between the outer race 81 of the one-way clutch 89 and the gear housing 40 can be suppressed regardless of the material of the gear housing 40, and the reliability of the connection between the one-way clutch 89 and the housing 11 can be improved.

In the present embodiment, the outer ring 81 and the holding member 90 are coupled by press fitting. However, the outer ring 81 and the holding member 90 may be coupled to each other by another structure. For example, the outer ring 81 and the holding member 90 may be coupled by spline fitting. In this case, by forming the outer ring 81 and the holding member 90 from the same material, the gap in which the splines are fitted can be suppressed from being enlarged. As a result, the spline fitting can be prevented from dropping off, and the reliability of the connection between the one-way clutch 89 and the housing 11 can be improved.

According to the present embodiment, the holding member 90 has the cylindrical portion 91 into which the outer ring 81 is press-fitted. Thus, the one-way clutch 89 can be assembled to the holding member 90 by press-fitting, and the assembly process can be simplified.

According to the present embodiment, the housing 11 has the base portion 41 provided with the housing recess 43d, and the housing recess 43d houses the cylindrical portion 91. The base 41 is composed of a different material from the outer race 81. This enables the material of the base portion 41 of the housing 11 to be selected without considering the material of the one-way clutch 89, thereby improving the degree of freedom in design.

According to the present embodiment, the base 41 is composed of an aluminum alloy. Aluminum alloys are lightweight and can be manufactured by die casting. Therefore, even if the housing 11 having the base portion 41 has a complicated shape, it can be manufactured at a relatively low cost.

According to the present embodiment, the housing 11 includes the motor housing 30 and the gear housing 40 that hold the holding member 90 by sandwiching the flange portion 92 from the vertical direction. In this way, the flange portion 92 of the holding member 90 is sandwiched between the motor housing 30 and the gear housing 40 in the vertical direction, whereby the rotation of the holding member 90 can be suppressed with a simple structure.

According to the present embodiment, the motor housing 30 and the gear housing 40 are fixed to each other by the bolts 70 extending in the up-down direction, and the flange portion 92 is provided with the bolt insertion holes 94 into which the bolts 70 are inserted. Thereby, the holding member 90 can be fixed using the bolt 70 that fixes the motor case 30 and the gear case 40. Further, since the bolt 70 passes through the bolt insertion hole 94, the rotation of the holding member 90 can be suppressed more reliably.

According to the present embodiment, the holding member 90 and the outer ring 81 are made of an iron-based alloy. The iron-based alloy has high rigidity and is relatively inexpensive, and is suitable for realizing a structure for suppressing the idling of the one-way clutch 89.

According to the present embodiment, the holding member 90 is formed by press working. This enables the holding member 90 to be manufactured at low cost.

While one embodiment of the present invention has been described above, the configurations and combinations thereof in the embodiment are examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the spirit of the present invention. The present invention is not limited to the embodiments.

For example, the use of the motor unit of the above-described embodiment and its modified examples is not particularly limited. The motor unit of the above-described embodiment and its modified examples is mounted on, for example, an electric pump, an electric power steering apparatus, and the like.

In the above embodiment, the lower bearing 29B is constituted by the one-way clutch 89, but the lower bearing and the one-way clutch 89 may be provided separately.

In the above-described embodiment and the modifications thereof, the gear housing 40 is provided, but the gear housing 40 may be omitted.

Description of the reference symbols

10: a motor unit; 11: a housing; 20: a motor main body; 21: a stator; 25: a rotor; 30: a motor housing (first member); 40: a gear housing (second member); 41: a base portion (outer ring holding portion); 43 d: a receiving recess; 70: a bolt; 89: a one-way clutch; 81: an outer ring; 82: an inner ring; 90: a holding member; 91: a cylindrical portion; 92: a flange portion; 94: a bolt insertion hole; j: a central axis.

Claims

1. A motor unit is provided with:

a motor main body having a rotor that rotates about a central axis extending in a vertical direction and a stator located radially outward of the rotor;

a one-way clutch having an inner ring and an outer ring, the inner ring being coupled to the rotor;

a housing that houses the motor main body; and

a holding member fixed to the housing and coupled to the outer race,

the holding member is made of the same material as the outer ring.

2. The motor unit according to claim 1,

the holding member has a cylindrical portion into which the outer ring is press-fitted.

3. The motor unit according to claim 1 or 2, wherein,

the housing has an outer ring holding portion provided with a housing recess portion that houses the cylindrical portion,

the outer ring holding portion is made of a different material from the outer ring.

4. The motor unit according to claim 3,

the outer ring holding portion is made of an aluminum alloy.

5. The motor unit according to any one of claims 1 to 4,

the holding member has a flange portion extending along a plane perpendicular to the central axis,

the housing includes a first member and a second member that hold the holding member by sandwiching the flange portion from the vertical direction.

6. The motor unit according to claim 5,

the first member and the second member are fixed to each other by a bolt extending in an up-down direction,

the flange portion is provided with a bolt insertion hole which penetrates in the vertical direction and into which the bolt is inserted.

7. The motor unit according to any one of claims 1 to 6,

the holding member and the outer ring are made of an iron-based alloy.

8. The motor unit according to any one of claims 1 to 7,

the holding member is formed by press working.