WO2020166531A1

WO2020166531A1 - Motor unit

Info

Publication number: WO2020166531A1
Application number: PCT/JP2020/004962
Authority: WO
Inventors: 雄平山口; 佐藤　孝弘; 真郷青野; 留介佐藤
Original assignee: 日本電産株式会社
Priority date: 2019-02-13
Filing date: 2020-02-07
Publication date: 2020-08-20
Also published as: CN113228475A

Abstract

A motor unit according to an embodiment of the present invention comprises: a motor body having a rotor that rotates around a center axis extending in the vertical direction and a stator positioned on a radial outside of the rotor; a control unit that is positioned above the motor body and controls the rotation of the rotor; a housing that accommodates the motor body; and an upper cover that covers the control unit form above. The upper cover has: a first region overlapping the control unit when viewed in the vertical direction; and a second region positioned outside the control unit and below the first region when viewed in the vertical direction. The second region is provided with fixing holes passing through the upper cover in the vertical direction, and the upper cover is fixed to the housing by bolts inserted into the fixing holes.

Description

Motor unit

The present invention relates to a motor unit.

This application is based on Japanese Patent Application No. 2019-023905 filed on February 13, 2019. This application claims priority benefit to the application. The entire contents of which are incorporated herein by reference.

In recent years, a motor integrated with a control unit is being adopted for the purpose of simplifying the assembly process. Such a motor includes a motor main body having a rotor and a stator, a control unit located above the motor main body to control the rotation of the rotor, and a cover surrounding the control unit from the outside in the radial direction. For example, Patent Document 1 discloses a configuration in which a motor body and a cover are fixed to each other by a snap fit portion. The snap-fit portion includes a hook portion provided on the cover and a claw portion provided on the motor body. The snap fit portion fixes the motor body and the cover to each other by hooking the hook portion on the claw portion.
Japanese Patent Laid-Open No. 2018-126041

In the above structure for fixing the motor body and the cover, it may be required to more firmly fix the motor body and the cover. However, in order to more firmly fix the motor body and the cover, the motor is often upsized.

In view of the above circumstances, an object of the present invention is to provide a motor unit capable of firmly fixing an upper cover that covers a control unit while suppressing an increase in size of the motor.

One aspect of a motor unit of the present invention is a motor main body having a rotor that rotates about a central axis extending in the vertical direction and a stator that is located radially outside the rotor, and a motor main body that is located above the motor main body. A control unit that controls the rotation of the rotor; a housing that houses the motor body; and an upper cover that covers the control unit from above, the upper cover overlapping the control unit when viewed from above and below. 1 area|region and the 2nd area|region located below the said 1st area|region outside the said control part seeing from an up-down direction, The said 2nd area|region penetrates the said upper cover in an up-down direction. A fixing hole is provided, and the upper cover is fixed to the housing by a bolt inserted into the fixing hole.

According to one aspect of the present invention, there is provided a motor unit capable of firmly fixing an upper cover covering a control unit while suppressing an increase in size of the motor.

FIG. 1 is a perspective view showing the outer appearance of a motor unit according to an embodiment. FIG. 2 is a plan view of the motor unit according to the embodiment as seen from above. FIG. 3 is a view showing an internal structure of the motor unit of the embodiment, and is a sectional view taken along line III-III of FIG. FIG. 4 is a diagram showing an internal structure of an upper portion of the motor unit according to the embodiment, and is an enlarged view of a main part of FIG. 3. FIG. 5 is a diagram showing an internal structure of a lower portion of the motor unit according to the embodiment, and is an enlarged view of a main part of FIG. FIG. 6 is an exploded perspective view showing a state where the upper cover of the motor unit according to the embodiment is removed. FIG. 7 is an enlarged cross-sectional view showing the internal structure of the motor unit of the modification.

FIG. 1 is a perspective view showing the appearance of the motor unit 10 of this embodiment. FIG. 2 is a plan view of the motor unit 10 of the present embodiment as seen from above. FIG. 3 is a view showing the internal structure of the motor unit 10 of the present embodiment, which is a sectional view taken along the line III-III of FIG. As shown in FIGS. 1 to 3, the motor unit 10 includes a motor body 20, a motor housing (housing) 30, a gear housing (lower cover) 40, a controller 50 (see FIG. 3), and an upper cover 60. And

In the following description, the direction parallel to the central axis J (see FIG. 3) is simply referred to as “axial direction” or “vertical direction”, the radial direction around the central axis J is simply referred to as “radial direction”, The circumferential direction about the central axis J, that is, the circumference of the central axis J is simply referred to as “circumferential direction”. Further, in the following description, “plan view” means a state viewed from the axial direction. Further, in the present specification, the upper side of FIG. 3 in the axial direction along the central axis J is simply referred to as “upper side”, and the lower side is simply referred to as “lower side”. It should be noted that the vertical direction does not indicate the posture of the motor unit 10 and the positional relationship and direction of each part when it is incorporated in an actual device. Moreover, in the following drawings, in order to make each structure easy to understand, the scale and the number of each structure may be different from the actual structure.

As shown in FIG. 3, the motor body 20 has a rotor 25 and a stator 21. The rotor 25 rotates about a central axis J extending along the up-down direction. The rotor 25 has a shaft 26, a rotor core 27, a plurality of magnets 28, and a sensor magnet 26m.

The shaft 26 is arranged along the central axis J extending in the vertical direction. The shaft 26 has a columnar shape extending in the vertical direction. The shaft 26 is rotatably supported around the central axis J by an upper bearing 29A and a lower bearing 29B. An upper bearing 29A that supports the upper portion of the shaft 26 is held by the motor housing 30. The upper bearing 29A is located above the stator 21. A lower bearing 29B that supports the lower portion of the shaft 26 is held by the gear housing 40. The lower bearing 29B is located below the stator 21. In this embodiment, the lower bearing 29B has a one-way clutch function.

FIG. 4 is a diagram showing the internal structure of the upper portion of the motor unit 10 of the present embodiment, and is an enlarged view of the main parts of FIG. A sensor magnet 26m is fixed to the upper end of the shaft 26. The sensor magnet 26m rotates around the central axis J together with the shaft 26.

As shown in FIG. 3, the rotor core 27 has a columnar shape extending in the vertical direction. The rotor core 27 has a fixing hole portion 27a that penetrates the rotor core 27 in the vertical direction. The shape of the fixing hole portion 27a viewed in the up-down direction is a circular shape with the central axis J as the center. The shaft 26 is passed through the fixing hole portion 27a. The shaft 26 is fixed to the rotor core 27 by press fitting or adhesion. The shaft 26 may be fixed to the rotor core 27 via a resin member or the like. As a result, 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 on the outer peripheral surface. The plurality of magnets 28 are arranged along the circumferential direction. The magnets 28 that are adjacent to each other in the circumferential direction are arranged such that their magnetic poles facing in the radial direction are reversed. The plurality of magnets 28 are arranged at equal intervals along the circumference along the circumference.

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

The stator core 22 has a tubular core back portion 23a centered on the central axis J and a plurality of teeth portions 23b extending inward in the radial direction from the core back portion 23a. As shown in FIG. 1, the core back portion 23a has a core outer peripheral surface 22a that faces outward in the radial direction. The core outer peripheral surface 22a extends along the circumferential direction. As will be described later, the core outer peripheral surface 22a of the core back portion 23a is exposed from the motor housing 30.

A plurality of teeth portions 23b are provided at equal intervals in the circumferential direction around the central axis J. The coil 24 is wound around the teeth portion 23b via an insulating insulator.

As shown in FIGS. 3 and 4, the motor housing 30 houses the motor body 20. In addition, in this specification, "accommodating" is a concept including not only the case where the whole object enters inside but also surrounding at least a part of the object from the periphery. The motor housing 30 has a motor holding portion 32, a bearing holder 33, and a collar 34.

The motor holding portion 32 is made of resin. More specifically, the motor holding portion 32 is an insert molded product including the stator 21, the bearing holder 33, and the collar 34. In other words, the motor holding portion 32 is the resin portion 32p that holds the stator 21, the bearing holder 33, and the collar 34. The resin portion 32p is made of a resin material.

As shown in FIGS. 1 to 3, the motor holding portion 32 has a columnar portion 35, a bulge portion 36, and a housing extension portion 37. The columnar portion 35, the bulging portion 36, and the housing expansion portion 37 are a single member.

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

The plate-shaped portion 35a is provided above the stator 21. The plate-shaped portion 35a is a disk-shaped portion that is orthogonal to the central axis J. As shown in FIG. 4, a bearing holding recess 35h is provided on the lower surface of the plate-shaped portion 35a. The bearing holding recess 35h is located at the center of the plate-shaped portion 35a. The bearing holding recess 35h is recessed upward. The bearing holder 33 is held in the bearing holding recess 35h. The plate-shaped portion 35a holds the upper bearing 29A via the bearing holder 33.

The filling portion 35b surrounds the tooth portion 23b and the coil 24 in the stator 21, and is provided between the tooth portion 23b and the coil 24 that are adjacent to each other in the circumferential direction. The filling portion 35b extends downward from the plate-shaped portion 35a.

As shown in FIGS. 1 to 3, the bulging portion 36 is provided on the outer peripheral portion of the columnar portion 35. The bulging portion 36 projects radially outward from the outer peripheral surface of the columnar portion 35. The bulging portions 36 are provided at a plurality of places at intervals in the circumferential direction. In the present embodiment, the bulging portions 36 are provided at three places spaced apart in the circumferential direction. As shown in FIG. 3, each bulging portion 36 extends in the vertical direction. Each bulging portion 36 has a hole portion 36h extending along the up-down direction. That is, the resin portion 32p is provided with the hole portion 36h.

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

As shown in FIG. 4, 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 lid portion 33b. The holder cylinder portion 33a and the lid portion 33b are a single member. The holder tubular portion 33a has a cylindrical shape extending in the vertical direction. An upper bearing 29A is arranged on the radially inner side of the holder tubular portion 33a. The lid portion 33b is a disc-shaped member that extends in the vertical direction and covers the upper end portion of the holder tubular portion 33a. A sensor opening 33c is provided at the center of the lid 33b. The sensor magnet 26m is arranged inside the sensor opening 33c in the radial direction when viewed in the vertical direction. The lid 33b of the bearing holder 33 and the sensor magnet 26m are covered by the plate-shaped portion 35a from above with a gap therebetween.

The collar 34 is arranged in the hole 36h of the bulging portion 36. The collar 34 is made of metal and has a cylindrical shape extending in the vertical direction. The collar 34 is provided with a bolt insertion hole 34h penetrating in the vertical direction. The collar 34 is molded in the bulging portion 36. As shown in FIGS. 3 to 5, the collar 34 is exposed on the upper surface 36a and the lower surface 36b of the bulging portion 36. The vertical length of the collar 34 is slightly larger than the vertical thickness of the bulging portion 36 (the vertical spacing between the upper surface 36a and the lower surface 36b). The upper end portion of the collar 34 is located above the upper surface 36 a of the bulging portion 36. The lower end of the collar 34 is located below the lower surface 36b of the bulging portion 36. As a result, when the bolt 70 described later is fastened, the upper cover 60 and the gear housing 40 hit the upper and lower sides of the collar 34, and the axial force of the bolt 70 excessively acts on the resin motor holding portion 32. Can be suppressed.

FIG. 5 is a diagram showing the internal structure of the lower portion of the motor unit 10 of the present embodiment, and is an enlarged view of the main parts of FIG. As shown in FIG. 5, the gear housing 40 is provided below the motor housing 30. The gear housing 40 has a base portion 41 and an outer cylinder portion 42. The base portion 41 and the outer cylinder portion 42 are a single member. The gear housing 40 is made of metal such as aluminum alloy.

The base 41 is a disc-shaped portion that intersects in the vertical direction. A bearing holding hole 43 is provided at the center of the base 41. The bearing holding hole 43 extends vertically through the base 41.

The outer cylinder portion 42 is a cylindrical shape extending in the vertical direction, and extends downward from the outer peripheral portion of the base portion 41 in the vertical direction. A gear accommodating recess 44 is provided inside the outer tubular portion 42 in the radial direction. The gear housing recess 44 opens below the gear housing 40.

As shown in FIG. 5, a plurality of screw holes 46 are provided on the upper surface of the gear housing 40. Each screw hole 46 is opposed to the bolt insertion hole 34h of the collar 34 provided in the bulging portion 36 of the motor housing 30 in the vertical direction. A female screw groove is provided on the inner peripheral surface of each screw hole 46.

A bearing holding plate 47 is provided above the base 41 of the gear housing 40. The bearing holding plate 47 has a bearing holding cylinder portion 47a and a flange portion 47b. The bearing holding cylinder portion 47a and the flange portion 47b are a single member.

The bearing holding cylinder portion 47a has a cylindrical shape extending in the vertical direction. The bearing holding cylinder portion 47a is inserted inside the bearing holding hole 43 of the base portion 41 in the radial direction. The outer ring 29a of the lower bearing 29B is press-fitted inside the bearing holding cylinder portion 47a in the radial direction.

The flange portion 47b extends radially outward from the upper end of the bearing holding cylinder portion 47a. The flange portion 47b extends along the upper surface of the base portion 41. The flange portion 47b is sandwiched between the motor holding portion 32 of the motor housing 30 and the gear housing 40. As a result, the bearing holding plate 47 is fixed to the motor housing 30. The bearing holding plate 47 is preferably made of the same material as the outer ring 29a of the lower bearing 29B.

FIG. 6 is an exploded perspective view showing a state where the upper cover 60 of the motor unit 10 of this embodiment is removed. As shown in FIGS. 4 and 6, the control unit 50 is located above the motor body 20. The control unit 50 controls the rotation of the rotor 25. The control unit 50 includes a control board 51 and a plurality of electronic components 52.

The control board 51 has a flat plate shape and is arranged above the plate-like portion 35 a of the motor housing 30 with a space. The control board 51 extends along a plane orthogonal to the vertical direction. The control board 51 is provided parallel to the upper surface of the plate-shaped portion 35a.

The control board 51 has a main body portion 51a and an extension portion 51b. The main body portion 51a and the expansion portion 51b are a single member. The main body portion 51 a is provided above the columnar portion 35 of the motor holding portion 32 of the motor housing 30. As a result, the motor body 20 and the bearing holder 33 face the control unit 50 in the vertical direction. The expansion portion 51b extends radially outward from the main body portion 51a. The expansion portion 51b is also located radially outward of the columnar portion 35 of the motor housing 30. The extension portion 51b is arranged in a region overlapping with the housing extension portion 37 when viewed from above and below.

As shown in FIG. 3, the extension part 51b of the control part 50 is provided with a connector part 53 extending downward. As shown in FIGS. 1 and 3, at least a part of the connector portion 53 projects downward from the housing extension portion 37. An external connector (not shown) that externally supplies electric power and inputs/outputs control signals is detachably connected to the connector portion 53.

The various electronic components 52 are mounted on the upper surface and the lower surface of the control board 51. Here, it is preferable that a large electronic component having a large vertical dimension is mounted on the lower surface of the extension portion 51b of the motor housing 30 that is radially outward of the columnar portion 35 and is housed in the housing extension portion 37.

Further, as shown in FIG. 4, a rotation sensor 54 is mounted as an electronic component 52 on the lower surface of the control board 51. That is, the control unit 50 has the rotation sensor 54. The rotation sensor 54 faces the sensor magnet 26m provided on the shaft 26 with a space in the vertical direction. That is, the rotation sensor 54 is located above the sensor magnet 26m.
The rotation sensor 54 detects a change in magnetic flux density caused by the rotation of the sensor magnet 26m.

As shown in FIGS. 1 to 4, the upper cover 60 faces the motor housing 30 in the vertical direction. The upper cover 60 covers the upper part of the motor housing 30. The upper cover 60 has a cover base portion 61 and a cover fixing portion 62. The cover base portion 61 and the cover fixing portion 62 are a single member. The upper cover 60 is made of metal.

The cover base 61 covers the main body 51a and the extension 51b of the controller 50 from above. The cover base 61 has a flat plate shape orthogonal to the central axis J and covers the columnar portion 35 of the motor housing 30 and the upper portion of the housing extension portion 37. A part of the cover base 61 is provided with a protruding cover part 61b protruding upward. Among the electronic components 52 provided in the control unit 50, the electronic components 52 having a large protrusion size upward from the control board 51, the connection terminals, the wiring, and the like are provided in the protrusion cover unit 61b in order to avoid interference with the upper cover 60. It is provided on the lower side. The cover base 61 constitutes a first area A1 that overlaps the control unit 50 when viewed in the vertical direction.

The cover fixing portions 62 are provided at a plurality of locations on the outer peripheral portion of the cover base portion 61 that are spaced apart in the circumferential direction. The cover fixing portion 62 projects radially outward from the cover base portion 61. The cover fixing portion 62 faces the bulging portion 36 of the motor housing 30 in the vertical direction.

As shown in FIG. 4, the upper surface 62a of the cover fixing portion 62 is located below the upper surface 61a of the cover base 61. The cover fixing portion 62 constitutes a second area A2 located below the cover base portion 61 (first area A1) around the controller 50 when viewed in the vertical direction.

As shown in FIGS. 3, 4, and 6, the cover fixing portion 62 is provided with a fixing hole 64 that vertically penetrates the upper cover 60. When viewed in the vertical direction, the fixing hole 64 overlaps the bolt insertion hole 34h of the collar 34 provided in the bulging portion 36.

As shown in FIG. 3, the upper cover 60 is fixed to the motor housing 30 with bolts 70. The shaft portion 71 of the bolt 70 is fastened to the screw hole 46 of the gear housing 40 from the fixing holes 64 provided in the plurality of cover fixing portions 62, the bolt insertion holes 34h of the collar 34, and the screw holes 46. The axial force of the bolt 70 is transmitted between the cover fixing portion 62 of the metallic upper cover 60 and the metallic gear housing 40 via the metallic collar 34. This prevents the axial force of the bolt 70 from excessively acting on the bolt insertion hole 34h.

As shown in FIG. 4, the head 72 of the bolt 70 contacts the upper surface 62 a of the cover fixing portion 62 of the upper cover 60 while the bolt 70 is fastened. In this state, the upper end surface 72t of the head 72 of the bolt 70 is located below 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 portion 61 is the upper surface of the protruding cover portion 61b.

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

The motor unit 10 has a seal structure 80 that suppresses moisture from entering between the motor housing 30 and the upper cover 60. The seal structure 80 is provided along the inner peripheral edge of a region where the upper surface 30t of the motor housing 30 and the lower surface 60b of the upper cover 60 face each other in the vertical direction. The seal structure 80 is provided in an annular shape so as to surround the entire circumference of the control unit 50 when viewed in the vertical direction. The plurality of bolts 70 are arranged outside the seal structure 80 when viewed in the vertical direction.

The seal structure 80 has a concave groove 81, a rib 82, and a gasket portion (sealing portion) 83. The groove 81 is provided in the motor housing 30. The concave groove 81 is recessed downward from the upper surface 30t of the motor housing 30. The recessed groove 81 is provided radially outside the control unit 50 and continuously over the entire circumference in the circumferential direction.

The rib 82 is provided on the upper cover 60. The rib 82 projects downward from the lower surface 60b of the upper cover 60. The ribs 82 extend radially outward of the control unit 50 and continuously over the entire circumference of the lower surface 60b of the upper cover 60 in the circumferential direction. The rib 82 is arranged at the center of the groove 81 in the groove width direction with the upper surface 30t of the motor housing 30 and the lower surface 60b of the upper cover 60 facing each other in the vertical direction. In addition, a lower end of the rib 82 is vertically spaced apart from the bottom surface of the concave groove 81 with the upper surface 30t of the motor housing 30 and the lower surface 60b of the upper cover 60 facing each other in the vertical direction. Are arranged. As a result, a gap is provided between the outer peripheral surface of the rib 82 and the inner peripheral surface of the concave groove 81.

The gasket portion 83 is located between the motor housing 30 and the upper cover 60 in the vertical direction. The gasket portion 83 has an annular shape that surrounds the control unit 50 when viewed in the vertical direction. The gasket portion 83 is provided in the gap between the outer peripheral surface of the rib 82 and the inner peripheral surface of the concave groove 81. The gasket portion 83 is made of a cured liquid gasket. Such a gasket portion 83 is formed by applying an uncured liquid gasket into the groove 81, inserting the rib 82 into the groove 81, and then curing the liquid gasket.

As shown in FIG. 6, a positioning recess 85 is provided on the outer peripheral portion of the upper cover 60. The positioning recesses 85 are provided at a plurality of locations spaced apart in the circumferential direction, for example, five locations in the present embodiment. The positioning recess 85 is recessed upward from the lower surface 60b of the upper cover 60 and is open outward in the radial direction. That is, the positioning recess 85 has a surface 85a facing outward in the radial direction.

A positioning protrusion 86 is provided on the outer periphery of the motor housing 30. The positioning protrusions 86 are provided at a plurality of locations spaced apart in the circumferential direction, for example, five locations in this embodiment. The positioning protrusion 86 projects upward from the upper surface 30t of the motor housing 30. Each positioning convex portion 86 is arranged to face the positioning concave portion 85 in the vertical direction.

The positioning protrusion 86 is inserted into the positioning recess 85 with the lower surface 60b of the upper cover 60 and the upper surface 30t of the motor housing 30 abutting each other in the vertical direction. In this state, the surface 86a of the positioning projection 86 facing inward in the radial direction contacts the surface 85a of the positioning recess 85 facing outward in the radial direction.

By providing the positioning concave portion 85 and the positioning convex portion 86 at three or more positions in the circumferential direction, the upper cover 60 and the motor housing 30 are positioned in the radial direction. Accordingly, as described above, the rib 82 is arranged in the groove width direction central portion of the concave groove 81 over the entire circumference.

As shown in FIG. 4, the recessed groove 81 is provided in the bank portion 89 protruding upward from the outer edge of the upper surface of the motor housing 30. In the present embodiment, the control board 51 is located above the bank portion 89. Therefore, the outer peripheral portion 51r of the control board 51 can be arranged so as to overlap the bank portion 89 when viewed from the up and down direction, and a large area of the control board 51 can be secured. In addition, according to this embodiment, it is possible to secure a large gap between the lower surface of the control board 51 and the upper surface of the motor housing 30, and it is easy to mount electronic components on the lower surface of the control board 51. As a modification, the control board 51 may be arranged radially inward of the bank portion 89 and below the upper surface of the bank portion 89. In this case, since the control board 51 can be arranged as close to the motor body 20 as possible, the motor unit 10 can be downsized in the vertical direction.

According to the present embodiment, the upper cover 60 has the cover fixing portion 62 (second area A2) located below the cover base 61 around the cover base portion 61 (first area A1) overlapping the controller 50. Have. The upper cover 60 is fixed to the motor housing 30 by bolts 70 inserted into fixing holes 64 provided in the cover fixing portion 62. As a result, it is possible to prevent the bolt 70 from projecting far above the upper cover 60. Moreover, the upper cover 60 and the motor housing 30 can be firmly fixed by the bolts 70. Therefore, it is possible to provide the motor unit 10 that can firmly fix the upper cover 60 that covers the control unit 50 while suppressing the size increase of the motor unit 10.

According to the present embodiment, the upper end surface 72t of the bolt 70 is located below the uppermost surface 61t of the upper cover 60 in the cover base 61. This makes it possible to more effectively prevent the bolt 70 from projecting above the upper cover 60. Therefore, it is possible to firmly fix the upper cover 60 that covers the control unit 50 while suppressing an increase in the size of the motor unit 10.

According to the present embodiment, the shaft portion 71 of the bolt 70 is inserted into the metal collar 34 embedded in the resin portion 32p of the motor housing 30. When the motor housing 30 has the resin portion 32p, the fastening of the bolt 70 may be loosened due to the difference in linear expansion coefficient between the bolt 70 and the resin portion 32p. By inserting the shaft portion 71 of the bolt 70 into the metal collar 34, which has a linear expansion coefficient closer to that of the metal bolt 70 than the resin portion 32p, it is possible to suppress loosening of the bolt 70.

According to the present embodiment, the motor housing 30 has the gear housing 40 located below the resin portion 32p. The bolt 70 is fastened to the screw hole 46 provided in the gear housing 40. The bolt 70 penetrates the resin portion 32p. As a result, the upper cover 60 and the gear housing 40 can be simultaneously fixed to the motor housing 30 by the bolt 70.

According to the present embodiment, the motor unit 10 has the gasket portion 83 located between the motor housing 30 and the upper cover 60 in the vertical direction. As a result, it is possible to prevent water or the like from entering the accommodation space of the control unit 50 from between the motor housing 30 and the upper cover 60. Further, the plurality of bolts 70 are arranged outside the gasket portion 83 when viewed in the vertical direction. Therefore, it is possible to prevent water from entering the accommodation space of the control unit 50 through the holes (the fixing holes 64, the hole portions 36h, and the bolt insertion holes 34h) into which the bolts 70 are inserted.

According to the present embodiment, the gasket portion 83 is made of a liquid gasket that is hardened between the concave groove 81 and the rib 82. Therefore, in the manufacturing process, by filling the uncured liquid gasket into the concave groove 81 and inserting the rib 82 into the concave groove 81, the gasket portion 83 is arranged without a gap between the concave groove 81 and the rib 82. It is possible to realize an airtight seal structure easily and surely.

According to this embodiment, the positioning recess 85 provided on the motor housing 30 and the positioning projection 86 provided on the upper cover 60 are in radial contact with each other. As a result, the upper cover 60 is positioned in the radial direction with respect to the motor housing 30. Therefore, it is possible to suppress partial deviation in the gap between the inner peripheral surface of the concave groove 81 and the outer peripheral surface of the rib 82, and to uniformly provide the gasket portion 83 in the concave groove 81.

According to the present embodiment, the motor housing 30 has the plate-shaped portion 35a that covers the sensor magnet 26m located at the upper end of the shaft 26. Therefore, the plate-shaped portion 35a partitions the space in which the control unit 50 is housed from the space in which the motor body 20 is housed. When the motor unit 10 of this embodiment is used for an oil pump, the rotor 25 may be used in a state of being immersed in oil. According to the present embodiment, the plate-shaped portion 35a covers the sensor magnet 26m from above, so that the fluid (for example, oil) on the motor body 20 side can be suppressed from entering the space that houses the control unit 50.

According to the present embodiment, the bearing holder 33 faces the control unit 50 in the vertical direction. Similarly, according to the present embodiment, the bearing holder 33 faces the upper cover 60 in the vertical direction. As a result, the motor body 20, the control unit 50, and the upper cover 60 are arranged in the vertical direction, and the motor unit 10 can be prevented from increasing in the radial direction.

According to this embodiment, the upper cover 60 contacts the motor housing 30 and is directly fixed to the motor housing 30. Therefore, the vertical size of the motor unit 10 can be reduced as compared with the case where another member is interposed between the motor housing 30 and the upper cover 60.

(Modification)
FIG. 7 is an enlarged cross-sectional view showing the internal structure of the upper portion of the motor unit 10B of the modified example of the above embodiment. The motor unit 10B of the present modification is different from the above-described motor unit 10 mainly in the configuration of the seal structure 80B. The same components as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 7, the motor unit 10B has a solid gasket member 88 in place of the gasket portion 83 made of the liquid gasket shown in the above embodiment. The gasket member 88 is formed of an elastic material such as a rubber material. The gasket member 88 is a gasket molded product that is previously molded in a similar shape to the shape of the recessed groove 81 and has a predetermined shape. The gasket member 88 as described above is compressed by the lower surface 60 b of the upper cover 60 while being fitted in the groove 81. As a result, the gasket member 88 is sandwiched between the upper surface 30t of the motor housing 30 and the lower surface 60b of the upper cover 60, and exhibits sealing performance. Even when such a seal structure 80B is adopted, it is possible to prevent moisture or the like from entering the accommodation space of the control unit 50 from between the motor housing 30 and the upper cover 60, as in the above-described embodiment. it can.

Although one embodiment of the present invention and its modified example have been described above, each configuration and the combination thereof in the embodiment and the modified example are examples, and addition of the configuration is not departing from the scope of the present invention. , Omissions, substitutions and other changes are possible. The present invention is not limited to the embodiments.

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

Further, in the above-described embodiment and its modification, the concave groove 81 may be provided on the lower surface 60b of the upper cover 60 and the rib 82 may be provided on the upper surface 30t of the motor housing 30. That is, one of the upper surface of the motor housing 30 and the lower surface of the upper cover 60 may be provided with the concave groove 81, and the other may be provided with the rib 82.

Further, in the above-described embodiment and its modification, the positioning recess 85 may be provided in the motor housing 30, and the positioning projection 86 may be provided in the upper cover 60. That is, one of the upper surface of the motor housing 30 and the lower surface of the upper cover 60 may be provided with the positioning projection 86 projecting toward the other side, and the other may be provided with the positioning recess 85.

Further, in the above-described embodiment and its modification, the case where the bolt 70 is fastened to the screw hole 46 of the gear housing 40 from the upper cover 60 side has been illustrated. However, as another example, a bolt may be penetrated from the gear housing 40 side to the motor housing 30 and the upper cover 60, and a screw shaft may be projected upward from the upper cover 60 to fasten the nut.

Further, in the above-described embodiment and its modification, the motor housing 30 is made of resin and the motor body 20 is insert-molded, but the invention is not limited to this. The motor housing 30 may be made of metal, or the motor body 20 may be inserted and arranged inside the tubular motor housing in the radial direction.

Further, although the structure having the gear housing 40 is shown in the above-described embodiment and its modification, it is also possible to adopt a configuration not having the gear housing 40.

10, 10B... Motor unit, 20... Motor body, 21... Stator, 25... Rotor, 26... Shaft, 26m... Sensor magnet, 29A... Upper bearing (bearing), 30... Motor housing (housing), 30t... Top surface, 32p ... Resin part, 33... Bearing holder, 34... Collar, 36h... Hole part, 40... Gear housing (lower cover), 46... Screw hole, 50... Control part, 54... Rotation sensor, 60... Upper cover, 60b... Bottom surface , 61t... Top face, 64... Fixing hole, 70... Bolt, 71... Shaft part, 72t... Top face, 80, 80B... Seal part, 81... Recessed groove, 82... Rib, 83... Gasket part (seal part), 85... Positioning concave portion, 85a... Surface facing radially outward, 86... Positioning convex portion, 86a... Surface facing radially inner side, 88... Gasket member (sealing portion), A1... First area, A2... Second area, J... central axis

Claims

A motor body having a rotor rotating about a central axis extending in the up-down direction and a stator located radially outside the rotor;
A control unit located on the upper side of the motor body for controlling rotation of the rotor;
A housing that houses the motor body,
An upper cover that covers the control unit from above,
The upper cover is
A first region that overlaps the control unit when viewed from above and below,
A second region located outside the control unit and below the first region when viewed from above and below,
In the second region, a fixing hole that penetrates the upper cover in the vertical direction is provided,
The motor unit, wherein the upper cover is fixed to the housing by a bolt inserted into the fixing hole.
The motor unit according to claim 1, wherein the upper end surface of the bolt is located below the uppermost surface of the upper cover in the first region.
The housing is
A resin portion formed of a resin material and provided with a hole portion extending in the vertical direction,
A tubular collar arranged in the hole portion and extending in the vertical direction,
The motor unit according to claim 1, wherein the shaft portion of the bolt is inserted into the collar.
The housing has a lower cover located below the resin portion,
The motor unit according to claim 3, wherein the bolt penetrates the resin portion and is fastened to a screw hole provided in the lower cover.
The motor unit has an annular seal portion that is located between the housing and the upper cover in the vertical direction and surrounds the control portion when viewed from the vertical direction,
The motor unit according to any one of claims 1 to 4, wherein the bolt is arranged outside the annular seal portion when viewed from above and below.
The seal portion is a gasket portion made of a cured liquid gasket,
Of the upper surface of the housing and the lower surface of the upper cover,
On one side, a concave groove filled with the liquid gasket is provided,
The motor unit according to claim 5, wherein a rib to be inserted into the groove is provided on the other side.
The seal portion is a gasket member,
Of the upper surface of the housing and the lower surface of the upper cover,
On one side, a concave groove for accommodating the gasket member is provided,
The motor unit according to claim 5, wherein the other compresses the gasket member in the groove.
Of the upper surface of the housing and the lower surface of the upper cover,
On one side, a positioning protrusion protruding to the other side is provided,
On the other side, a positioning concave portion into which the positioning convex portion is inserted is provided,
The motor unit according to any one of claims 1 to 7, wherein a surface of the positioning protrusion facing inward in the radial direction contacts a surface of the positioning recess facing outward in the radial direction.
Further comprising a bearing located above the stator,
The rotor is
A shaft rotatably supported by the bearing,
A sensor magnet fixed to the upper end of the shaft,
The control unit has a rotation sensor located above the sensor magnet,
The housing has a plate-shaped portion that holds the bearing through a bearing holder,
9. The motor unit according to claim 1, wherein the plate-shaped portion covers the sensor magnet from above.
The motor unit according to claim 9, wherein the bearing holder vertically faces the control unit.
The motor unit according to claim 9 or 10, wherein the bearing holder vertically opposes the upper cover.
The motor unit according to any one of claims 1 to 11, wherein the upper cover comes into contact with the housing and is directly fixed to the housing.