Driving device

Abstract

To provide a driving device capable of releasing heat with high efficiency.SOLUTION: A driving device 10 includes a motor part 20, a circuit part 30, and a housing 40. The circuit part 30 includes a circuit board 31 on which an electronic component 32 related to energization control of a motor coil 21 is mounted and which is formed extending outward relative to a motor region in which the motor part 20 is projected in an axial direction. The housing 40 includes a housing main body 41 in which a motor housing part 411 for accommodating the motor part 20 and a circuit housing part 412 for accommodating the circuit part 30 are formed integrally, and a cover 61 that closes the opening on the circuit housing part 412 side. The heat of the circuit part 30 can be received in at least one of the housing main body 41 and the cover 61. The housing 40 has a heat release part 65. The heat release part 65 includes a heat release fin 56 formed in a protruding way in a peripheral wall part 55 formed surrounding an outer edge of the circuit board 31.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] Conventionally, there is known a mechanically and electrically integrated motor equipped with a control board that controls the motor body. For example, in Patent Document 1, a heat sink is composed of a bearing holder having a holder body and a protrusion, and a heat transfer member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-44984 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the surface area of ​​the heat dissipation surface is relatively small, and heat dissipation into the air is limited.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a drive device capable of dissipating heat with high efficiency. [Means for solving the problem]

[0006] The drive device of the present invention includes a motor section (20), a circuit section (30), and a housing (40). The motor section includes a stator (22) around which a motor winding (21) is wound, a rotor (23) that rotates when current is applied to the motor winding, and a shaft (25) that rotates integrally with the rotor. The circuit unit has a circuit board (31) on which electronic components (32) related to current control of the motor windings are mounted, and which is formed to extend outside a motor area when the motor unit is projected in the axial direction.

[0007] The housing has a housing main body (41, 42) in which a motor housing section (411, 421) for accommodating a motor section and a circuit housing section (412, 422) for accommodating a circuit section are integrally formed, and a cover (61, 71) for closing an opening on the circuit housing section side, and at least one of the housing main body and the cover can receive heat from the circuit section. The housing has a heat dissipation section (65), which includes peripheral wall heat dissipation sections (56, 57, 58, 74, 75) formed to protrude from a peripheral wall section (55, 73) formed to surround the outer edge of the circuit board. This can improve the heat dissipation efficiency. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an electric motorcycle to which a drive device according to a first embodiment is applied. [Diagram 2] FIG. 2 is a cross-sectional view of the drive device according to the first embodiment. [Diagram 3] FIG. 2 is a side view of the drive device according to the first embodiment. [Figure 4] 4 is a view taken in the direction of the arrow IV in FIG. 3. [Diagram 5] FIG. 4 is a view taken in the direction of the arrow V in FIG. [Figure 6] FIG. 11 is a side view of a drive device according to a second embodiment. [Figure 7] FIG. 7 is a view taken in the direction of an arrow VII in FIG. 6. [Figure 8] FIG. 8 is a view taken in the direction of the arrow VIII in FIG. 6. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 11 is a schematic diagram showing an electric motorcycle to which a drive device according to a third embodiment is applied. [Figure 11] FIG. 11 is a side view of a drive device according to a third embodiment. [Figure 12] 12 is a view taken in the direction of the arrow XII in FIG. 11. [Figure 13] 13 is a view taken in the direction of the arrow XIII in FIG. 11. [Figure 14] 14 is a view taken in the direction of the arrow XIV in FIG. 11. [Figure 15]15 is a cross-sectional view taken along line XV-XV of FIG. 14. [Figure 16] FIG. 13 is a side view of a drive device according to a fourth embodiment. [Figure 17] FIG. 17 is a view taken in the direction of the arrow XVII in FIG. [Figure 18] 18 is a view taken in the direction of the arrow XVIII in FIG. 16. [Figure 19] 19 is a view taken in the direction of the arrow XIX in FIG. 16. [Figure 20] 20 is a cross-sectional view taken along the line XX-XX in FIG. 19. [Figure 21] FIG. 13 is a cross-sectional view of a drive device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A driving device according to the present invention will be described below with reference to the drawings. In the following, in a number of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

[0010] (First embodiment) A first embodiment is shown in Figs. 1 to 5. As shown in Fig. 1, a driving device 10 is applied to, for example, an electric motorcycle 90. The electric motorcycle 90 is provided with a main battery 96 of, for example, 48 [V], an auxiliary battery 97 of, for example, 12 [V], and the driving device 10. The driving device 10 is connected to the main battery 96 and is driven by the power of the main battery 96. In Fig. 1, the driving device 10 is provided on the rear wheel 92 side of the electric motorcycle 90, but the driving device 10 may be provided on the front wheel 91 side, or on the front wheel 91 and the rear wheel 92.

[0011] 2 to 5, the drive device 10 includes a motor unit 20, a circuit unit 30, and a housing 40. The drive device 10 is a so-called "mechanically and electrically integrated" type in which the circuit unit 30 is provided on one side of the motor unit 20 in the axial direction.

[0012] The motor unit 20 is, for example, a three-phase brushless motor, and the driving force is transmitted to the rear wheel 92 via gears (not shown) etc. The electric motorcycle 90 runs using the driving force of the motor unit 20, and the motor unit 20 is a running motor (so-called main motor).

[0013] Fig. 2 is a view corresponding to the cross section taken along line II-II in Fig. 5. As shown in Fig. 2, the motor section 20 has a stator 22 around which a motor winding 21 is wound, a rotor 23, a shaft 25, and the like. The stator 22 is fixed to a housing 40. The rotor 23 is provided radially inside the stator 22 and is provided to be rotatable relative to the stator 22.

[0014] The shaft 25 is fitted into the rotor 23 and rotates integrally with the rotor 23. The shaft 25 is rotatably supported by bearings 251 and 252. One end of the shaft 25 is exposed from the housing 40 towards the circuit unit 30, and a magnet 255 is provided thereon. The other end of the shaft 25 is an output end 258, which is exposed from the housing 40 on the side opposite the circuit unit 30. The output end 258 is connected to the rear wheel 92 via a reduction gear or the like (not shown). As a result, the rear wheel 92 is driven by the driving force of the motor unit 20.

[0015] Hereinafter, the imaginary line extending from the axis of the shaft 25 is referred to as the rotation axis Ax. The axial direction of the motor section 20 is referred to as the "motor axial direction" or simply the "axial direction" as appropriate. In the axial direction, the lower side of the paper in FIG. 2 is referred to as the "output end side" and the upper side of the paper is referred to as the "cover side". Furthermore, the area obtained by projecting a tube section 43 of a housing main body 41, which will be described later, in the axial direction is referred to as the "motor area", and the area extending outside the motor area is referred to as the "extension area" (see FIG. 3). Note that in FIG. 3 and other figures, the motor area and extension area have been omitted to avoid complication.

[0016] The circuit unit 30 has a circuit board 31. The circuit board 31 is fixed to the housing 40 by fixing members such as screws (not shown), and is formed to extend outside the motor area on one radial side. Various electronic components 32 related to motor control are mounted on the circuit board 31. Hereinafter, the surface of the circuit board 31 facing the motor unit 20 will be referred to as a motor surface 311, and the surface opposite the motor unit 20 will be referred to as a cover surface 312.

[0017] The electronic components 32 include a switching element 321, height components 323 such as a capacitor, and a control component 325 such as a microcomputer. The switching element 321 constitutes an inverter related to switching the current supply to the motor windings 21, and is mounted on the motor surface 311 and the cover surface 312 of the circuit board 31. In this embodiment, a part of the switching element 321 is mounted outside the motor area. The height components 323 are mounted on the motor surface 311 of the circuit board 31 outside the motor area. The control component 325 is mounted on the cover surface 312 of the circuit board 31 within the motor area.

[0018] The connector 35 is provided in the extension region, and a connector terminal 351 is connected to the circuit board 31. In this embodiment, the frontage of the connector 35 faces the output end side, and the insertion / removal direction of the harness (not shown) is parallel to the rotation axis Ax. The frontage orientation and the insertion / removal direction may be different. By providing the connector 35 in the extension region, it is possible to effectively utilize the dead space created by extending the circuit unit 30 side radially from the motor region.

[0019] As shown in Figs. 2 to 5, the housing 40 has a housing main body 41, a cover 61, and a frame member 81. The housing main body 41 has a motor housing section 411 that houses the motor section 20, and a circuit housing section 412 that houses the circuit section 30, which are integrally formed from a metal material such as aluminum. The housing main body 41 has a cylindrical section 43, a heat sink section 45, an extension section 51, and a peripheral wall section 55, which are integrally formed from a metal material such as aluminum. When viewed from the cover side, the housing 40 is formed in a shape that combines a semicircle and a rectangle as a whole. The semicircle portion has a smaller diameter than the cylindrical section 43, and is provided within the motor region. The rectangular section is formed by extending from the semicircle portion to the outside of the motor region.

[0020] In this embodiment, the cylinder portion 43 and the output end side of the heat sink portion 45 form the motor housing portion 411, and the cover side of the heat sink portion 45, the extension portion 51 and the peripheral wall portion 55 form the circuit housing portion 412. In other words, the heat sink portion 45 can be considered as a partition wall that separates the motor portion 20 side and the circuit portion 30 side, and is shared by the motor housing portion 411 and the circuit housing portion 412.

[0021] The stator 22 is fixed to the radially inner side of the cylindrical portion 43. An annular heat dissipation fin 435 is integrally formed on the radially outer side of the cylindrical portion 43. The heat dissipation fins 435 are formed in multiple stages that protrude radially outward from the cylindrical portion 43 and are arranged in the axial direction. A frame member 81 is provided on the output end side of the cylindrical portion 43.

[0022] The frame member 81 is formed in a substantially circular plate shape from, for example, metal. The frame member 81 is attached to the output end side of the cylindrical portion 43 by a fixing member such as a screw so as to close the opening of the cylindrical portion 43. The frame member 81 is formed with a bearing holder 811. The bearing 251 is provided in the bearing holder 811.

[0023] The heat sink portion 45 is provided on the cover side of the cylindrical portion 43, and is formed with a bearing holding portion 451. The bearing holding portion 451 is provided with a bearing 252. Thereby, the shaft 25 is rotatably supported by the housing 40.

[0024] The extension portion 51 is formed continuously with the heat sink portion 45, and extends radially outward from the tubular portion 43. Hereinafter, the direction in which the extension portion 51 extends radially outward from the tubular portion 43 is referred to as the extension direction. The extension portion 51 has an accommodating recess 511 formed on its cover side surface. The tall part 323 is disposed in the accommodating recess 511.

[0025] The peripheral wall portion 55 stands along the outer edge of the heat sink portion 45 and the extension portion 51, and is provided approximately perpendicular to the circuit board 31. The peripheral wall portion 55 is composed of a curved surface portion 551 standing on the semicircular portion side, a side wall portion 552 extending from the curved surface portion 551 to the outside of the motor area, and a tip surface 553 which is the end surface on the extension area side. The circuit board 31 and the electronic components 32 mounted on the circuit board 31 are accommodated in the accommodation space surrounded by the cover side surface of the heat sink portion 45, the extension portion 51, and the peripheral wall portion 55.

[0026] The cover 61 is made of, for example, metal, and is attached to the housing body 41 with fixing members such as screws so as to close the opening on the cover side of the housing body 41. This makes it possible to prevent foreign matter such as water droplets and dust from entering the inside of the housing 40.

[0027] In this embodiment, the drive unit 10 is connected to the main battery 96, and when a relatively high voltage (for example, 96 [V] when two 48 [V] main batteries 96 are connected in series) is applied, the drive unit 10 becomes hot due to heat generation in the circuit section 30, etc., and heat countermeasures are therefore required. Therefore, in this embodiment, in order to promote heat dissipation from the circuit section 30, heat dissipation fins 56, 62 are provided on the circuit housing side.

[0028] The heat dissipation fins 56 are provided to protrude outward from the peripheral wall portion 55. In this embodiment, the heat dissipation fins 56 are formed continuously across one side wall portion 552, the curved surface portion 551, and the other side wall portion 552, and are substantially perpendicular to the rotation axis Ax. In other words, the heat dissipation fins 56 are formed substantially parallel to the mounting surface of the circuit board 31. The heat dissipation fins 56 are formed in multiple stages in the axial direction.

[0029] The heat dissipation fins 62 are provided to protrude substantially perpendicularly from an outer surface 615, which is the end surface opposite the output end of the cover 61. In this embodiment, the heat dissipation fins 62 are formed in multiple rows that are substantially parallel to the side wall portion 552 and extend from the motor region side to the extension region side. In this embodiment, the heat dissipation fins 435, 56, and 62 form a heat dissipation portion 65.

[0030] As shown in Fig. 1, the drive unit 10 is mounted on the electric motorcycle 90 so that the rear side of the vehicle is the motor area and the front side is the extension area. Therefore, the cooling air generated by the vehicle running flows from the tip side of the extension part 51 to the motor area side (see Figs. 3 and 5). Therefore, in this embodiment, the heat dissipation fins 56, 62 are formed along the extension direction so as to follow the flow of the cooling air. By forming the heat dissipation fins 56, 62 so as to follow the flow of the cooling air, the circuit part 30 can be cooled with high efficiency by the cooling air.

[0031] As shown in FIG. 2, a heat receiving protrusion 456 is formed on the board facing surface 455 of the heat sink part 45 facing the circuit board 31. A heat receiving protrusion 612 is formed on the inner side surface 611 of the cover 61. The heat receiving protrusions 456, 612 are formed in an area where the electronic components 32 that require heat dissipation are mounted. In this embodiment, the electronic components 32 that require heat dissipation are the switching element 321 and the control component 325, which are provided so as to be able to dissipate heat to the heat receiving protrusions 456, 612 via the heat dissipation gel 33. In other words, in this embodiment, the housing main body 41 and the cover 61 can be considered to have a function as a case as well as a function as a heat sink related to heat dissipation of the circuit part 30. This allows the heat generated in the heat generating element by the passage of electricity to be dissipated with high efficiency.

[0032] In this embodiment, the housing 40 has an unbalanced shape in which the circuit housing protrudes radially to one side beyond the outer diameter of the motor housing. By making the circuit section 30 side protrude beyond the motor section 20 side, it is possible to ensure a mounting area and to improve heat dissipation by air cooling.

[0033] Furthermore, the driving device 10 is applied to an electric motorcycle 90, and there is a risk that the driving device 10 will vibrate due to external forces such as wind pressure and vehicle vibration. In this embodiment, the motor housing and the circuit housing are formed as a single unit into the housing main body 41, so that loosening or damage to the connection points between the motor unit 20 and the circuit unit 30 due to vibration can be prevented.

[0034] As described above, the drive device 10 includes the motor section 20, the circuit section 30, and the housing 40. The motor section 20 includes a stator 22 around which the motor windings 21 are wound, a rotor 23 that rotates when current is applied to the motor windings 21, and a shaft 25 that rotates integrally with the rotor 23. The circuit section 30 includes a circuit board 31 on which electronic components 32 related to current control of the motor windings 21 are mounted, and which is formed to extend outside the motor area when the motor section 20 is projected in the axial direction.

[0035] The housing 40 has a housing main body 41 in which a motor housing section 411 that accommodates the motor section 20 and a circuit housing section 412 that accommodates the circuit section 30 are integrally formed, and a cover 61 that covers the opening on the circuit housing section 412 side, and at least one of the housing main body 41 and the cover 61 can receive heat from the circuit section 30.

[0036] The housing 40 has a heat dissipation section 65, which includes heat dissipation fins 56 formed integrally with a peripheral wall section 55 formed to surround the outer edge of the circuit board 31 and protruding therefrom. By providing the heat dissipation fins 56 and increasing the surface area contributing to heat dissipation and reducing thermal resistance, it is possible to enhance heat dissipation from the circuit section 30. This allows for a higher motor output. In this embodiment, the heat dissipation fins 56 are formed on the peripheral wall section 55 constituting the circuit housing section 412 in the housing main body 41 and have a rib structure, which improves the strength of the circuit housing section 412 formed to protrude from the motor area.

[0037] In the housing body 41, a heat receiving protrusion 456 is formed on a board facing surface 455 which faces the circuit board 31 at a location where an electronic component 32 requiring heat dissipation is mounted. In the cover 61, an inner surface 611 which faces the circuit board 31 is formed on a location where an electronic component 32 requiring heat dissipation is mounted. In this embodiment, the "electronic component requiring heat dissipation" is the switching element 321 and the control component 325.

[0038] Forming the heat-receiving protrusions 456, 612 allows the heat generating element and the housing 40 to be placed close to each other, improving heat dissipation efficiency. In addition, a space is created between the circuit board 31 and the housing 40 in areas other than where the elements requiring heat dissipation are mounted, increasing the freedom of arrangement of elements other than the heat generating element.

[0039] The heat dissipation section 65 includes heat dissipation fins 62 formed integrally with and protruding from an outer surface 615 parallel to the cover surface 312 which is the mounting surface of the circuit board 31. This increases the surface area contributing to heat dissipation, thereby improving the heat dissipation efficiency of the circuit section 30.

[0040] The housing body 41 has a cylindrical portion 43 that accommodates the motor portion 20 radially inside. The heat dissipation portion 65 includes heat dissipation fins 435 that are formed integrally with the cylindrical portion 43 and protrude radially outward. This can improve the efficiency of heat dissipation from the motor portion 20 side.

[0041] The electronic components 32 include a switching element 321 for switching current through the motor windings 21. At least a portion of the switching element 321 is disposed in an extension area that is outside the motor area. This allows the thermal efficiency of the switching element 321 to be increased.

[0042] The drive unit 10 is mounted on the electric motorcycle 90 in a state exposed to the outside. The heat dissipation fins 56, 62, which are heat dissipation parts provided on the circuit housing part 412, are formed in a linear fashion and are arranged along the direction of cooling air generated by the running of the electric motorcycle 90. In this embodiment, the heat dissipation fins 56, 62 are formed along the front-rear direction of the vehicle so that the air generated in the front-rear direction of the vehicle as the vehicle runs can be used as cooling air. This allows the circuit part 30 to dissipate heat with high efficiency by the cooling air.

[0043] Second embodiment The second embodiment is shown in Figs. 6 to 9. In the following embodiments, the circuit housing section and the cover are different from those of the above-mentioned embodiment, and this point will be mainly described. In the housing main body 42 of this embodiment, the motor housing section 421 and the circuit housing section 422 are integrally formed from a metal material, and the housing main body 42 has a cylindrical section 43, a heat sink section 46, and an extension section 52. In this embodiment, for simplification, the illustration of the heat dissipation fins 435 of the cylindrical section 43 is omitted, but they may be formed in the same manner as in the first embodiment. The same applies to the fourth embodiment.

[0044] The heat sink portion 46 and the extension portion 52 have board fixing portions 461 and 521 formed to protrude on the opposite side to the output end. The circuit board 31 is fixed to the board fixing portions 461 and 521 by fixing members such as screws (not shown). The board fixing portions 461 and 521 are formed in relatively outer regions of the heat sink portion 46 and the extension portion 52 so as to be able to hold the outer edge side of the circuit board 31. In this embodiment, the switching element 321 is not mounted on the motor surface 311 of the circuit board 31, and no heat-receiving protrusions are formed on the board-facing surface 465 of the heat sink portion 46.

[0045] The cover 71 is formed in a generally cylindrical shape with a bottom, having a cover portion 72 and a peripheral wall portion 73, and is provided so as to cover the circuit board 31. The cover 71 is provided so that the cover portion 72 is opposite the output end, and the opening side of the peripheral wall portion 73 is the output end side.

[0046] The cover portion 72 is formed in a manner generally similar to the cover 61 of the first embodiment, and a heat receiving protrusion 722 is formed on an inner surface 721. Although no heat dissipation fins are provided on an outer surface 725 of the present embodiment, the heat dissipation fins 62 similar to those of the first embodiment may be provided.

[0047] The peripheral wall portion 73 is composed of a curved surface portion 731 provided in the semicircular portion, a side wall portion 732 extending from the curved surface portion 731 to the outside of the motor area, and a tip surface 733 which is the end surface on the extension area side.

[0048] The heat dissipation fins 74 are formed integrally with the cover 71, protrude outward from the peripheral wall portion 73, and are provided in multiple stages in the axial direction. In this embodiment, the heat dissipation fins 74 are formed continuously across one side wall portion 732, the curved surface portion 731, and the other side wall portion 732, and are formed approximately perpendicular to the rotation axis Ax. The heat dissipation fins 74 are included in the heat dissipation portion 65.

[0049] That is, in the first embodiment, the outer peripheral wall of the circuit housing portion 412 is formed by a peripheral wall portion 55 provided on the housing main body 41, whereas in the present embodiment, the outer peripheral wall of the circuit housing portion 422 is formed by a peripheral wall portion 73 provided on the cover 71.

[0050] By providing peripheral wall 73 on the cover 71 side and forming heat dissipation fins 74 on peripheral wall 73, it is possible to improve the heat dissipation efficiency of the elements mounted on the cover surface 312 side of circuit board 31. Fig. 9 shows, as an example, a case in which switching element 321 is not mounted on the motor surface 311 side of circuit board 31.

[0051] 9, when it is desired to increase heat dissipation from the cover surface 312 more than from the motor surface 311, it is preferable in terms of heat dissipation to provide the peripheral wall portion 73 on the cover 71. When it is desired to increase heat dissipation from the motor surface 311 more than from the cover surface 312, it is preferable to provide the peripheral wall portion 73 on the housing main body 41 side as in the first embodiment.

[0052] In this embodiment, the peripheral wall 73 formed to surround the outer edge of the circuit board 31 is provided on the cover 71. The heat dissipation section 65 includes heat dissipation fins 74 formed integrally with the peripheral wall 73 to protrude therefrom. This can improve heat dissipation from the cover 71 side. In addition, the same effects as those of the above embodiment can be achieved.

[0053] Third embodiment The third embodiment is shown in Fig. 10 to Fig. 15. As shown in Fig. 10, in this embodiment, the drive unit 10 is mounted on an electric motorcycle 90 so that the lower side in the vertical direction is the motor area and the upper side is the extension area. Therefore, the cooling air generated by the vehicle running flows in a direction perpendicular to the extension direction (see Fig. 12, etc.). Therefore, in this embodiment, as shown in Fig. 11 to Fig. 15, heat dissipation fins are formed along a direction perpendicular to the extension direction.

[0054] The heat dissipating fins 57, 58 protrude approximately perpendicular to the rotation axis Ax on the outer side of the peripheral wall portion 55 and are formed in multiple stages in the axial direction. The heat dissipating fin 57 is formed on the curved surface portion 551, and the heat dissipating fin 58 is formed on the tip surface 553.

[0055] The heat dissipation fins 63 are provided to protrude substantially perpendicularly from the outer surface 615 of the cover 61. In this embodiment, the heat dissipation fins 63 are formed in multiple rows along a direction perpendicular to the extension direction and substantially parallel to the tip surface 553. In this embodiment, the heat dissipation fins 57, 58, and 63 are included in the heat dissipation portion 65.

[0056] (Fourth embodiment) 16 to 20 show the fourth embodiment. In this embodiment, as in the second embodiment, a peripheral wall portion 73 is provided on the cover 71 side. The heat dissipation fins 75 protrude substantially perpendicularly to the rotation axis Ax on the outer side of the peripheral wall portion 73, and are formed in multiple stages in the axial direction. In this embodiment, the heat dissipation fins 75 are included in the heat dissipation portion 65.

[0057] In this embodiment, heat dissipation fins 75 are formed on the tip surface 733, but similar to the third embodiment, heat dissipation fins may also be provided on the curved surface portion 731. Although no heat dissipation fins are provided on the outer surface 725 of this embodiment, heat dissipation fins 63 similar to the third embodiment may be provided.

[0058] In the third and fourth embodiments, the heat dissipation fins 57, 58, 63, and 75 are formed perpendicular to the extension direction. As a result, when the drive unit 10 is mounted on the electric motorcycle 90 in the orientation shown in Fig. 10, for example, the heat dissipation fins 57, 58, 63, and 75 are arranged so as to follow the flow of cooling air. This allows the circuit unit 30 to dissipate heat with high efficiency. Even with this configuration, the same effects as the above embodiments can be achieved.

[0059] Fifth embodiment The fifth embodiment is shown in Fig. 21. In this embodiment, the switching elements 321 and the control parts 325 are mounted on the motor surface 311. Furthermore, all the switching elements 321 are arranged within the motor area.

[0060] An outer surface 515 on the output end side of the extension portion 51 is parallel to the motor surface 311, which is the mounting surface of the circuit board 31, and has heat dissipation fins 59 protruding and formed integrally therewith. The heat dissipation fins 59 are formed in a plurality of rows approximately parallel to the tip surface 553 on the side closer to the tube portion 43 than the connector 35. This makes it possible to enhance heat dissipation from the elements mounted in the extension area of ​​the motor surface 311 of the circuit board 31. Even with this configuration, the same effects as those of the above embodiment can be achieved. Note that in this embodiment, the heat dissipation fins 59 are included in the heat dissipation portion 65.

[0061] In the embodiment, the motor surface 311 and the cover surface 312 correspond to the "mounting surface", the switching element 321 and the control component 325 correspond to the "electronic component requiring heat dissipation", the heat dissipation fins 56, 57, 58, 74, 75 correspond to the "peripheral wall heat dissipation portion", the board-facing surface 455 and the inner surfaces 611, 721 correspond to the "board-facing surface", the heat dissipation fins 59, 62, 63 correspond to the "parallel surface heat dissipation portion", and the heat dissipation fin 435 corresponds to the "motor heat dissipation portion". Note that "parallel", "perpendicular", etc. are allowed to have an error that can be regarded as parallel and perpendicular. Also, the electric motorcycle 90 corresponds to the "vehicle".

[0062] (Other embodiments) In the above embodiment, the heat dissipation fins on the circuit housing side are formed and arranged parallel or perpendicular to the extension direction depending on the mounting direction of the drive unit on the electric motorcycle. In other embodiments, the heat dissipation fins may be formed in a direction other than parallel or perpendicular to the extension direction and inclined with respect to the extension direction. Also, in the above embodiment, the heat dissipation fins are formed continuously in a straight line from one side to the other side, and multiple heat dissipation fins are arranged in parallel. In other embodiments, the heat dissipation fins may be formed intermittently or may be arranged non-parallel, for example radially. Also, the shape and arrangement of the heat dissipation part may be different from those of the above embodiment.

[0063] In the above embodiment, the control components are mounted on the side relatively close to the curved surface of the circuit board, the switching elements are mounted in the boundary area between the motor area and the extension area, and the tall components are mounted in the extension area. In the above embodiment, the heat generating elements are mounted on both sides of the circuit board in the example of FIG. 2, on the cover surface of the circuit board in the example of FIG. 9, and on the motor surface of the circuit board in the example of FIG. 21. In other embodiments, the arrangement of the electronic components, including the mounting surface, may be different from that of the above embodiment. In the above embodiment, the electronic components that require heat dissipation are the switching elements and the control components. In other embodiments, electronic components other than the switching elements and the control components may be considered as "electronic components that require heat dissipation", and a heat receiving protrusion may be formed at the mounting location of the electronic components. Also, it is not necessary to form a heat receiving protrusion.

[0064] In the above embodiment, the drive unit is applied to the main motor of the electric motorcycle. In other embodiments, the drive unit may be applied to a device other than the main motor. Furthermore, the drive unit may be applied to a vehicle other than the electric motorcycle or to a device other than an in-vehicle device.

[0065] The present disclosure may also be stipulated as "the drive device according to any one of items 1 to 3, wherein the housing main body has a cylindrical portion (43) that accommodates the motor portion radially inward, and the heat dissipation portion includes a motor heat dissipation portion (435) formed to protrude radially outward from the cylindrical portion," "the drive device according to any one of items 1 to 4, wherein the electronic components include a switching element (321) for switching current flow through the motor windings, and at least a portion of the switching element is disposed in an extension region that is outside the motor region," or "the drive device according to any one of items 1 to 5, wherein the heat dissipation portion provided in the circuit housing portion is formed in a linear manner and arranged along the direction of cooling air."

[0066] As described above, the present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0067] 10 Drive device 20 Motor section 21 Motor winding 22 stator 23 rotor 25 shaft 30 circuit section 31 circuit board 40 housing 41, 42: Housing body 411, 421 Motor housing part 412, 422...Cover housing part 61, 71 Cover 65 Heat dissipation section 56, 57, 58, 74, 75... Heat dissipation fins (peripheral wall heat dissipation parts) 59, 62, 63: Heat dissipation fins (parallel surface heat dissipation section) 435···Heat dissipation fin (motor heat dissipation part)

Claims

1. a motor section (20) having a stator (22) around which motor windings (21) are wound, a rotor (23) that rotates when current is applied to the motor windings, and a shaft (25) that rotates integrally with the rotor; a circuit section (30) having a circuit board (31) on which electronic components (32) relating to current control of the motor windings are mounted and which is formed to extend outside a motor area projected in the axial direction of the motor section; a housing (40) including a housing main body (41, 42) in which a motor housing portion (411, 421) for accommodating the motor portion and a circuit housing portion (412, 422) for accommodating the circuit portion are integrally formed, and a cover (61, 71) for closing an opening on the circuit housing portion side, and the housing (40) is capable of absorbing heat from the circuit portion at least on one side of the housing main body and the cover; Equipped with The housing has a heat dissipation portion (65), The drive device includes a peripheral wall heat dissipation portion that is formed by protruding from a peripheral wall that is formed surrounding an outer edge of the circuit board.

2. The drive device described in claim 1, wherein a heat-receiving convex portion (456, 612, 722) is formed on a board-facing surface (455, 611, 721) of at least one of the housing body and the cover, which is the surface facing the circuit board, at a location where the electronic component (321, 325) requiring heat dissipation is mounted.

3. 3. The drive device according to claim 1, wherein the heat dissipation portion includes a parallel surface heat dissipation portion (59, 62, 63) formed to protrude from an outer surface (515, 615) parallel to a mounting surface (311, 312) of the circuit board.

4. The housing body has a cylindrical portion (43) that accommodates the motor portion radially inside, 3. The drive device according to claim 1, wherein the heat dissipation portion includes a motor heat dissipation portion (435) formed to protrude radially outward from the cylindrical portion.

5. The electronic components include a switching element (321) for switching current flow to the motor windings, The drive device according to claim 1 or 2, wherein at least a part of the switching elements is disposed in an extension area that is outside the motor area.

6. It is mounted on a vehicle (90) in a state where it is exposed to the outside, 3. The drive unit according to claim 1, wherein the heat dissipation portion provided in the circuit housing portion is formed in a linear manner and arranged in a direction along a cooling airflow generated by the vehicle traveling.

Images