JP2024067996A - Drive unit - Google Patents

Abstract

To appropriately cool a heating component.SOLUTION: A drive unit 12 configured to drive a straddle-type vehicle includes: a motor 16; an inverter 20 configured to control the motor 16; and a cooling air passage 24 through which cooling air introduced from the outside flows. A first partial passage (partial passage) that is a part of the cooling air passage 24 is located between the inverter 20 and the motor 16 and is defined by a first wall surface (front surface) that is a wall surface of the inverter 20 and a second wall surface (back surface, bottom surface) that extends along the first wall surface and is a wall surface of the motor 16.SELECTED DRAWING: Figure 8

Description

The present invention relates to a drive unit using a motor.

Patent Document 1 discloses a saddle-type vehicle equipped with an electric motor and an inverter. In this saddle-type vehicle, the inverter is disposed in front of the electric motor.

JP 2021-84573 A

Recently, there has been a demand for technology that can optimally cool heat-generating components. The electric motor and inverter in Patent Document 1 are exposed to outside air when the saddle-type vehicle is running. This allows the electric motor and inverter to be cooled. However, depending on the arrangement of the electric motor and inverter, there is a risk that either or both of the electric motor and the inverter will not be exposed to outside air. In this case, the electric motor and inverter cannot be optimally cooled.

The present invention aims to solve the above-mentioned problems.

One aspect of the present invention is a drive unit for driving a saddle-type vehicle, comprising a motor, an inverter for controlling the motor, and a cooling air passage through which cooling air introduced from the outside flows, and a first partial passage that is a part of the cooling air passage is located between the inverter and the motor, and is defined by a first wall surface that is the wall surface of the inverter, and a second wall surface that is aligned with the first wall surface and is the wall surface of the motor.

According to the present invention, the motor and inverter can be cooled effectively regardless of the arrangement of the motor and inverter.

FIG. 1 is a schematic diagram of a saddle-type vehicle. FIG. 2 is a perspective view of the drive unit. FIG. 3 is a plan view of the drive unit. FIG. 4 is a bottom view of the drive unit. FIG. 5 is a front view of the drive unit. FIG. 6 is a right side view of the drive unit. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is a cross-sectional view taken along line IX-IX of FIG. FIG. 10 is a cross-sectional view taken along line XX in FIG. FIG. 11 is a plan view of the drive unit with the cover removed. FIG. 12 is a partially enlarged view of a partial passage.

[1 saddle-type vehicle 10]
1 is a schematic diagram of a saddle-ride type vehicle 10. The saddle-ride type vehicle 10 is an electric vehicle. For example, the saddle-ride type vehicle 10 is an electric two-wheeler. The saddle-ride type vehicle 10 is equipped with a drive unit 12. Power of the drive unit 12 is transmitted to a rear wheel 14 via drive system components (such as a chain, a belt, a drive shaft, etc.) not shown. The saddle-ride type vehicle 10 moves forward by being driven by the rear wheel 14.

[2. Structure of drive unit 12]
FIG. 2 is a perspective view of the drive unit 12. FIG. 3 is a plan view of the drive unit 12. FIG. 4 is a bottom view of the drive unit 12. FIG. 5 is a front view of the drive unit 12. FIG. 6 is a right side view of the drive unit 12. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 3. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 3. FIG. 10 is a cross-sectional view taken along line XX in FIG. 6. FIG. 11 is a plan view of the drive unit 12 with the cover 62 removed. Note that the "front-rear direction" used in the following description corresponds to the "front-rear direction" of the saddle riding type vehicle 10. Also, the "up-down direction" used in the following description corresponds to the "up-down direction" of the saddle riding type vehicle 10. Also, the "left-right direction" used in the following description corresponds to the "left-right direction" of the saddle riding type vehicle 10.

As shown in FIG. 2 etc., the drive unit 12 includes a motor 16, a speed reduction mechanism 18, an inverter 20, and a fan 22 (FIG. 7). The motor 16, the speed reduction mechanism 18, the inverter 20, and the fan 22 are integrated. Also, as shown in FIG. 8, FIG. 9 etc., the drive unit 12 includes a cooling air passage 24 through which cooling air flows. Cooling air (outside air) introduced into the inside of the drive unit 12 by the fan 22 flows through the cooling air passage 24. The cooling air cools the motor 16 and the inverter 20.

The motor 16 is an AC motor. The motor 16 is operated by receiving a current from the inverter 20. As shown in Figs. 7, 9, etc., the motor 16 includes a motor housing 26, a stator 28, a rotor 30, and a rotating shaft 32. The motor 16 shown in Figs. 7, 9, etc. is an inner rotor type motor. The motor 16 is disposed so that the axis A of the motor 16 (the axis A of each of the stator 28, the rotor 30, and the rotating shaft 32) is perpendicular to the front-rear direction (first direction) and the up-down direction. In other words, the motor 16 is disposed so that the axis A of the motor 16 extends in the left-right direction (second direction).

In this specification, the portion of the motor 16 that is located relatively rearward is referred to as the rear portion 34. Additionally, the portion of the motor 16 that is located relatively forward is referred to as the front portion 36. The boundary between the rear portion 34 and the front portion 36 in the front-rear direction is a surface that includes the axis A of the motor 16 and extends in the vertical and horizontal directions. Additionally, in this specification, the portion of the outer wall surface of the motor housing 26 that surrounds the stator 28 around the axis is referred to as the outer peripheral surface 38 of the motor 16.

9, etc., the outer peripheral surface 38 of the motor housing 26 at the rear portion 34 includes an upper surface 40, a rear surface 42, and a lower surface 44. The upper surface 40 faces upward. The rear surface 42 faces backward. The lower surface 44 faces downward. Meanwhile, at the front portion 36, the outer peripheral surface 38 of the motor 16 includes a curved surface 48. The curved surface 48 is located at a portion from the front end of the upper surface 40 to the front end of the lower surface 44. The curved surface 48 is an arc-shaped surface that protrudes forward along the outer periphery of the stator 28. The outer peripheral surface 38 of the front portion 36 is an arc-shaped surface, which reduces the air resistance generated in the drive unit 12 during driving. Also, as shown in FIG. 7, etc., the right surface 50 of the motor housing 26 faces rightward. The left surface 52 of the motor housing 26 faces leftward.

9, 11, etc., a rear groove 54 is formed in the rear surface 42. The inner surface of the rear groove 54 is included in the rear surface 42. The rear groove 54 extends along the rear surface 42 in a direction perpendicular to the rotation axis 32 (up-down direction). The rear groove 54 extends linearly from the lower end of the rear surface 42 to the upper end of the rear surface 42. An upper groove 56 is formed in the upper surface 40. The inner surface of the upper groove 56 is included in the upper surface 40. The upper groove 56 extends along the upper surface 40 in a direction perpendicular to the rotation axis 32 (front-rear direction). The upper groove 56 extends linearly from the rear end of the upper surface 40 to the boundary between the upper surface 40 and the curved surface 48. A curved groove 58 is formed in the curved surface 48. The inner surface of the curved groove 58 is included in the curved surface 48. The curved groove 58 extends along the curved surface 48 in a direction perpendicular to the rotation axis 32 (the circumferential direction of the stator 28). The curved groove 58 extends from the boundary between the upper surface 40 and the curved surface 48 to the boundary between the curved surface 48 and the lower surface 44.

9, the upper end of the rear groove 54 and the rear end of the upper groove 56 are connected to each other. The front end of the upper groove 56 and the rear end of the curved groove 58 are connected to each other. Furthermore, a plurality of heat dissipation fins 60 are formed inside the upper groove 56 and inside the curved groove 58. The heat dissipation fins 60 protrude from the bottom of the groove toward the outside of the groove. The heat dissipation fins 60 extend along the longitudinal direction of the groove.

As shown in Figures 3, 5, 9, etc., a resin cover 62 is attached to the top surface 40 and the curved surface 48. The cover 62 covers the entire upper groove 56 and part of the curved groove 58. As shown in Figure 9, the upper groove 56, the curved groove 58, and the cover 62 define a part of the cooling air passage 24. This part of the cooling air passage 24 is referred to as the partial passage 24c. The partial passage 24c extends along the top surface 40 and the curved surface 48 radially outward of the motor 16. In other words, the partial passage 24c is bent so as to protrude radially outward of the motor 16 when viewed from the right side.

9, the cover 62 extends from a first end located at the rear end of the upper surface 40 to a second end located between the front end and the lower end of the curved surface 48. The second end of the cover 62 is located at the discharge position P. At the discharge position P, an opening 64 of the cooling air passage 24 is formed. The opening 64 is an exhaust port for the cooling air. The opening 64 exhausts the cooling air that has flowed through the cooling air passage 24 (partial passage 24c). The opening 64 is formed to exhaust the cooling air in a direction between the downward direction and the rearward direction.

As shown in FIG. 3 etc., the reduction mechanism 18 is located on the left side of the motor 16. The reduction mechanism 18 reduces the rotation of the motor 16 and transmits it to the rear wheel 14. As shown in FIG. 7, FIG. 10 etc., the reduction mechanism 18 includes a reduction gear case 66, a plurality of gears 68, and an output shaft 70. The reduction gear case 66 is attached to the motor housing 26. The reduction gear case 66 covers the plurality of gears 68. The left end of the rotating shaft 32 protrudes from the left surface 52 of the motor housing 26.

7, 10, etc., in this embodiment, the multiple gears 68 include a first gear 68a, a second gear 68b, a third gear 68c, and a fourth gear 68d. The first gear 68a is attached to the left end of the rotating shaft 32. The second gear 68b and the third gear 68c are attached to the intermediate shaft 69. The fourth gear 68d is attached to the output shaft 70. The rotating shaft 32, the intermediate shaft 69, and the output shaft 70 are parallel to each other. The first gear 68a and the second gear 68b mesh with each other. The third gear 68c and the fourth gear 68d mesh with each other. The output shaft 70 is connected to the rear wheel 14 via a drive system component (a chain, a belt, a drive shaft, etc.). With the above configuration, the power of the motor 16 is transmitted to the rear wheel 14 via the rotating shaft 32, the first gear 68a, the second gear 68b, the intermediate shaft 69, the third gear 68c, the fourth gear 68d, the output shaft 70, and the drive system components.

The more gears 68 and shaft members are included in the reduction mechanism 18, the larger the reduction gear case 66 becomes. As shown in Figures 7, 10, etc., the reduction gear case 66 of this embodiment protrudes rearward compared to the stator 28. In this specification, the part of the reduction mechanism 18 located rearward of the rear end 29 of the stator 28 is referred to as the protruding portion 72. The output shaft 70 is included in the protruding portion 72. The output shaft 70 is parallel to the rotating shaft 32 of the motor 16. In the left-right direction, the right end of the output shaft 70 is located to the left of the left surface 52 of the motor housing 26.

As shown in FIG. 3 and other drawings, the inverter 20 is located behind the motor 16. The inverter 20 converts direct current supplied from a battery (not shown) into alternating current and supplies it to the motor 16. As shown in FIG. 7 and other drawings, the inverter 20 includes an inverter case 74, an inverter board 76, and a heat sink 78. The inverter board 76 and the inverter case 74 are attached to the rear side of the heat sink 78. The inverter case 74 covers the inverter board 76. The inverter board 76 is sealed by the inverter case 74 and the heat sink 78. The part of the heat sink 78 that faces forward is the front surface 80. The heat sink 78 is attached to the rear surface 42 of the motor housing 26. As described above, the rear surface 42 includes the inner surface of the rear groove 54. In other words, a part of the cooling air passage 24 is defined by the front surface 80 (first wall surface) of the heat sink 78 and the rear surface 42 (second wall surface) of the motor housing 26. In other words, a portion of the cooling air passage 24 is defined by the front surface 80 (first wall surface) and the inner surface of the rear groove 54. This portion of the cooling air passage 24 is referred to as the partial passage 24b. As shown in FIG. 9, the partial passage 24b is connected to the partial passage 24a. The partial passage 24b is located upstream of the partial passage 24a.

12 is a partially enlarged view of the partial passage 24b. FIG. 12 is a cross-sectional view in a plane parallel to the front-rear and left-right directions. The heat sink 78 has a plurality of heat dissipation fins 82 protruding into the partial passage 24b. The heat dissipation fins 82 extend along the longitudinal direction (up-down direction) of the partial passage 24b. The wall surface of the rear surface 42 located at the bottom of the rear groove 54 is referred to as the bottom surface 42b. The distance D1 between the adjacent heat dissipation fins 82 is greater than the distance D2 between the tip 84 of the heat dissipation fin 82 and the bottom surface 42b of the rear surface 42. If the distance D2 is greater than the distance D1, the cooling air is more likely to flow between the tip 84 of the heat dissipation fin 82 and the bottom surface 42b. On the other hand, the cooling air is less likely to flow between the adjacent heat dissipation fins 82. This reduces the cooling effect of the heat sink 78. In this embodiment, by making the distance D1 greater than the distance D2, the cooling air can easily flow between the adjacent heat dissipation fins 82. As a result, the cooling effect of the heat sink 78 is improved.

As shown in FIG. 7 etc., the fan 22 is located on the right side of the motor 16. The fan 22 is, for example, a sirocco fan. The fan 22 introduces outside air as cooling air into the drive unit 12. The right end of the rotating shaft 32 protrudes from the right surface 50 of the motor housing 26. The fan 22 is attached to the right end of the rotating shaft 32. The outer periphery of the fan 22 is covered with a shroud 88 made of resin. The shroud 88 is attached to the motor housing 26. The shroud 88 has an opening 90 and an introduction portion 92.

The opening 90 is an intake port for cooling air. The opening 90 introduces outside air as cooling air from the outside into the cooling air passage 24. The opening 90 is formed to introduce outside air from the right side. As shown in FIG. 8, the introduction portion 92 covers the outer periphery of the fan 22. Furthermore, as shown in FIG. 4, FIG. 8, etc., the introduction portion 92 covers a part of the lower surface 44 of the motor housing 26. The introduction portion 92 extends to the lower end of the rear groove 54 (partial passage 24b). As a result, as shown in FIG. 8, a part of the cooling air passage 24 is defined by the right surface 50 of the motor housing 26, the lower surface 44 of the motor housing 26, and the shroud 88. This part of the cooling air passage 24 is referred to as the partial passage 24a. As shown in FIG. 9, the partial passage 24a is connected to the partial passage 24b. The partial passage 24a is located upstream of the partial passage 24b.

[3. Positional Relationship Between the Motor 16, the Reduction Mechanism 18, and the Inverter 20]
As can be seen from FIG. 3, FIG. 5, etc., the inverter 20 is hidden behind the motor 16 in the front view. In other words, the inverter 20 is hidden behind the motor 16 in the first direction view. That is, the motor 16 and the inverter 20 overlap in the front view (first direction view). Also, as can be seen from FIG. 3, FIG. 6, etc., the reduction mechanism 18 is hidden behind the inverter 20 and the motor 16 in the right side view. In other words, the reduction mechanism 18 is hidden behind the inverter 20 and the motor 16 in the second direction view. That is, the reduction mechanism 18 and the inverter 20 overlap in the right side view (second direction view). Also, the reduction mechanism 18 and the motor 16 overlap in the right side view. Furthermore, as can be seen from FIG. 10, the output shaft 70 in the protruding portion 72 and the partial passage 24b overlap in the right side view. Note that the output shaft 70 in the protruding portion 72 and the inverter 20 may overlap in the right side view. As described above, in this embodiment, the inverter 20 is disposed in the space located behind the motor 16 and to the right of the speed reduction mechanism 18. This structure can prevent the inverter 20 from protruding from the motor 16 and the speed reduction mechanism 18. As a result, the drive unit 12 can be made smaller.

When viewed from the front, if at least a part of the motor 16 and at least a part of the inverter 20 overlap, it is possible to make the drive unit 12 smaller to some extent. Also, when viewed from the right side, if at least a part of the reduction gear mechanism 18 and at least a part of the inverter 20 overlap, it is possible to make the drive unit 12 smaller to some extent.

[4. Flow of cooling air]
In this embodiment, the cooling air is introduced into the cooling air passage 24 by the rotation of the fan 22 .

The fan 22 rotates in conjunction with the motor 16. For example, as shown in FIG. 8, the fan 22 rotates clockwise when viewed from the right side. Then, cooling air made from outside air is introduced into the inside of the drive unit 12 from the opening 90. As shown by the arrow 94a in FIG. 8 and FIG. 9, the cooling air introduced from the opening 90 flows through the partial passage 24a and reaches the lower end of the partial passage 24b.

As shown by arrow 94b in FIG. 9, the cooling air flows from the lower end of partial passage 24b toward the upper end of partial passage 24b, and reaches the rear end of partial passage 24c. That is, the cooling air flows upward (a direction intersecting the axial direction of motor 16) through partial passage 24b. The cooling air flowing through partial passage 24b comes into contact with heat dissipation fins 82 attached to inverter case 74 and bottom surface 42b of rear groove 54 formed in motor housing 26. As a result, the cooling air absorbs heat from inverter 20 and motor 16. Then, inverter 20 and motor 16 are cooled.

As shown by arrow 94c in FIG. 9, the cooling air flows along partial passage 24c and reaches opening 64. The cooling air flowing through partial passage 24c comes into contact with the inner wall of upper groove 56 and the heat dissipation fins 60 in upper groove 56. The cooling air flowing through partial passage 24c also comes into contact with the inner wall of curved groove 58 and the heat dissipation fins 60 in curved groove 58. As a result, the cooling air absorbs heat from motor 16. The cooling air is discharged from opening 64 in a direction between the downward and rearward directions.

The inverter 20 has a lower heat resistance than the motor 16. To deal with this, a partial passage 24b that cools the inverter 20 is arranged relatively upstream in the cooling air passage 24. Furthermore, a partial passage 24c that cools the motor 16 is arranged relatively downstream in the cooling air passage 24. This structure allows the inverter 20 to be cooled with priority, and prevents failure of the inverter 20.

According to this embodiment, the cooling air that flows through the cooling air passage 24 is discharged from the opening 64 in a direction between the downward and rearward directions. The cooling air discharged from the opening 64 is unlikely to hit the passenger of the saddle-ride type vehicle 10. In addition, the opening 64 discharges the cooling air in the direction opposite to the traveling direction of the saddle-ride type vehicle 10. This makes it possible to reduce the running resistance caused by the cooling air. In addition, because the opening 64 is not facing forward, foreign objects are unlikely to enter through the opening 64 while the saddle-ride type vehicle 10 is running.

[5. Other embodiments]
The drive unit 12 does not need to include the fan 22. For example, the partial passage 24a may be formed in a cover member attached to the motor housing 26, or in the motor housing 26 itself. In this case, the air intake of the partial passage 24a faces forward. As a result, outside air is introduced into the partial passage 24a from the air intake as the saddle riding type vehicle 10 travels.

In the above embodiment, the partial passage 24c located in the front portion 36 has a shape that curves forward when viewed from the right side. Alternatively, the partial passage 24c located in the front portion 36 may have a shape that curves when viewed from the right side, with multiple straight passages connected together.

[6 Invention Obtained from the Embodiments]
The invention that can be understood from the above embodiment will be described below.

The present invention relates to a drive unit (12) for driving a saddle-type vehicle (10), comprising a motor (16), an inverter (20) for controlling the motor, and a cooling air passage (24) through which cooling air introduced from the outside flows. A first partial passage (24b) which is a part of the cooling air passage is located between the inverter and the motor, and is defined by a first wall surface (80) which is the wall surface of the inverter, and a second wall surface (42, 42b) which is aligned with the first wall surface and is the wall surface of the motor.

The above configuration allows the motor and inverter to be cooled simultaneously. In addition, the above configuration allows the cooling air passage to be positioned between the motor and the inverter, preventing the cooling air passage from protruding from the motor and the inverter.

In an aspect of the present invention, the second wall surface may be the outer peripheral surface (38) of the motor.

In one aspect of the present invention, the drive unit may include a fan (22) that rotates in conjunction with the motor's rotating shaft (32) to introduce the cooling air, which is made from outside air, into the cooling air passage.

With the above configuration, the motor or inverter can be efficiently cooled by the cooling air introduced by the fan.

In one aspect of the present invention, the inverter is provided with a heat sink (78) that protrudes into the first partial passage, and the heat sink may have a plurality of heat dissipation fins (82) that extend along the longitudinal direction of the first partial passage.

With the above configuration, the inverter can be cooled efficiently by the heat dissipation fins.

In one aspect of the present invention, the heat sink is provided on the first wall surface, and the distance (D1) between adjacent heat dissipation fins may be greater than the distance (D2) between the tip (84) of the heat dissipation fin and the second wall surface.

With the above configuration, the cooling air flows more easily between adjacent heat dissipation fins than between the tip of the heat dissipation fin and the second wall surface. As a result, the cooling effect of the heat sink is improved.

In one aspect of the present invention, the axial direction of the motor corresponds to the left-right direction of the saddle-type vehicle, the front portion (36) of the motor is shaped like an arc when viewed in a second direction along the axial direction of the motor, and the inverter may be located behind the motor.

According to the above configuration, the outer peripheral surface of the front part is arc-shaped, and the inverter is located behind the motor. This reduces the amount of protrusion of the inverter from the top-bottom and left-right directions of the motor. This reduces the air resistance generated in the drive unit when the vehicle is traveling. In addition, according to the above configuration, because the inverter is located behind the motor, foreign objects such as stones are less likely to hit the inverter when the vehicle is traveling.

In one aspect of the present invention, the cooling air passage is formed so as to intersect with the axial direction of the motor, and the cooling air passage includes a second partial passage (24c) extending along the radially outer outer peripheral surface of the motor, and the second partial passage may be bent so as to protrude radially outward from the motor when viewed in a second direction along the axial direction of the motor.

The above configuration allows the contact area between the outer circumferential surface of the motor and the cooling air to be increased. This makes it possible to further suppress the temperature rise of the motor and improve the efficiency of the motor.

In an aspect of the present invention, the first partial passage may be located upstream of the second partial passage.

The above configuration allows the inverter to be cooled with priority, improving the durability of the inverter.

In one aspect of the present invention, the axial direction of the motor corresponds to the left-right direction of the saddle-ride type vehicle, and the first partial passage has an opening (64) for discharging the cooling air to the outside, and the opening may be formed to discharge the cooling air in a direction between a downward direction and a rearward direction.

According to the above configuration, the cooling air discharged from the opening is unlikely to hit the passenger of the saddle-riding type vehicle. Also, according to the above configuration, the opening discharges the cooling air in the direction opposite to the traveling direction of the saddle-riding type vehicle. Therefore, it is possible to reduce the running resistance caused by the cooling air. Also, according to the above configuration, because the opening is not facing forward, it is unlikely for foreign objects to enter through the opening while the saddle-riding type vehicle is traveling.

In one aspect of the present invention, the drive unit includes a resin shroud (88) around the fan, and a third partial passage (24a) that is a part of the cooling air passage is formed by the shroud, and the third partial passage may introduce outside air drawn into the fan into the first partial passage.

A resin shroud is easy to mold. Therefore, with the above configuration, it is easy to form part of the cooling air passage.

In one aspect of the present invention, the drive unit may include a resin cover (62) that covers the outer peripheral surface of the motor, and the second partial passage may be formed between the outer peripheral surface of the motor and the cover.

Resin covers are easy to mold. Therefore, with the above configuration, it is easy to form part of the cooling air passage.

In one aspect of the present invention, the drive unit includes a reduction mechanism (18) that reduces the rotation of the motor and transmits it to the output shaft (70), the motor, the inverter, and the reduction mechanism are integrated, the reduction mechanism includes a protrusion (72) that protrudes beyond the outer periphery of the stator (28) of the motor in a first direction perpendicular to the axial direction of the motor, and when viewed in a first direction along the first direction, the motor and the first partial passage overlap, and when viewed in a second direction along the axial direction, the protrusion and the first partial passage may overlap.

The above configuration can prevent the first partial passage from protruding from the motor and the reduction mechanism. As a result, the drive unit can be made smaller.

In an aspect of the present invention, the motor and the inverter may overlap when viewed in the first direction, and the protrusion and the inverter may overlap when viewed in the second direction.

The above configuration makes it possible to prevent the inverter from protruding from the motor and reduction gear mechanism. As a result, the drive unit can be made smaller.

In one aspect of the present invention, the first partial passage may be formed so that the direction of the cooling air flowing through the first partial passage intersects with the axial direction of the motor.

If the direction of the cooling air flowing through the first partial passage were to be aligned with the axial direction of the motor, the protruding portion of the reduction mechanism would be positioned to impede the flow of the cooling air through the first partial passage. This would prevent the cooling air from flowing smoothly through the first partial passage, reducing the cooling efficiency of the motor and inverter. In contrast, in the above configuration, the direction of the cooling air flowing through the first partial passage intersects with the axial direction of the motor. In this case, there is nothing to impede the direction of the cooling air. This allows the cooling air to flow smoothly, resulting in high cooling efficiency for the motor and inverter.

In one aspect of the present invention, the output shaft of the reduction mechanism is provided on the protruding portion, and the output shaft does not protrude from the protruding portion toward the first partial passage or the inverter, and the inverter or the first partial passage and the output shaft may overlap when viewed in the second direction.

The above configuration makes it possible to secure space for arranging the inverter or the first partial passage next to the protruding portion. The above configuration makes it possible to suppress the protrusion of the inverter or the first partial passage from the motor and the reduction mechanism. As a result, the drive unit can be made smaller.

The present invention is not limited to the above disclosure, and various configurations may be adopted without departing from the gist of the present invention.

REFERENCE SIGNS LIST 10 saddle-type vehicle 12 drive unit 16 motor 18 speed reduction mechanism 20 inverter 22 fan 24 cooling air passage 24a partial passage (third partial passage)
24b...Partial passage (first partial passage)
24c: partial passage (second partial passage) 28: stator 32: rotating shaft 36: front portion 40: upper surface (outer circumferential surface) 42: rear surface (second wall surface)
42b: bottom surface (second wall surface) 48: curved surface (outer circumferential surface)
62: Cover 64: Opening 70: Output shaft 72: Protrusion 78: Heat sink 80: Front surface (first wall surface)
82: heat dissipation fin 84: tip 88: shroud

Claims (15)

A drive unit for driving a saddle-type vehicle,
A motor;
an inverter for controlling the motor;
a cooling air passage through which cooling air introduced from the outside flows;
Equipped with
a first partial passage, which is a part of the cooling air passage, is located between the inverter and the motor, and is defined by a first wall surface which is a wall surface of the inverter, and a second wall surface which is along the first wall surface and is a wall surface of the motor.
Drive unit. 2. A drive unit according to claim 1,
The second wall surface is an outer circumferential surface of the motor.
Drive unit. 2. A drive unit according to claim 1,
a fan that rotates in conjunction with a rotating shaft of the motor to introduce the cooling air made of outside air into the cooling air passage;
Drive unit. A drive unit according to claim 1 or 2,
The inverter is provided with a heat sink protruding into the first partial passage,
The heat sink includes a plurality of heat dissipation fins extending along the longitudinal direction of the first partial passage.
Drive unit. A drive unit according to claim 4,
The heat sink is provided on the first wall surface,
A distance between adjacent ones of the plurality of heat dissipation fins is greater than a distance between a tip of the heat dissipation fin and the second wall surface.
Drive unit. 2. A drive unit according to claim 1,
an axial direction of the motor corresponds to a left-right direction of the saddle riding type vehicle,
a front portion of the motor is formed into an arc shape when viewed in a second direction along the axial direction of the motor,
The inverter is located behind the motor.
Drive unit. 2. A drive unit according to claim 1,
The cooling air passage is formed so as to intersect with an axial direction of the motor,
the cooling air passage includes a second partial passage extending along an outer circumferential surface of the motor in a radial direction,
the second partial passage is bent so as to protrude radially outward of the motor when viewed in a second direction along the axial direction of the motor.
Drive unit. A drive unit according to claim 7,
The first partial passage is located upstream of the second partial passage.
Drive unit. A drive unit according to claim 7,
the axial direction of the motor corresponds to a left-right direction of the saddle riding type vehicle,
the first partial passage has an opening for discharging the cooling air to the outside,
The opening is formed to discharge the cooling air in a direction between a downward direction and a rearward direction.
Drive unit. A drive unit according to claim 3,
A resin shroud is provided around the fan,
a third partial passage which is a part of the cooling air passage is defined by the shroud,
The third partial passage introduces the outside air drawn by the fan into the first partial passage.
Drive unit. A drive unit according to claim 7,
a resin cover that covers the outer circumferential surface of the motor,
The second partial passage is formed between the outer circumferential surface of the motor and the cover.
Drive unit. 2. A drive unit according to claim 1,
a reduction mechanism for reducing the rotation speed of the motor and transmitting the reduced rotation speed to an output shaft;
The motor, the inverter, and the reduction mechanism are integrated together,
the reduction mechanism includes a protruding portion that protrudes beyond an outer periphery of a stator of the motor in a first direction perpendicular to an axial direction of the motor,
When viewed in a first direction along the first direction, the motor and the first partial passage overlap each other,
When viewed in a second direction along the axial direction, the protrusion and the first partial passage overlap each other.
Drive unit. A drive unit according to claim 12,
When viewed in the first direction, the motor and the inverter overlap each other,
When viewed in the second direction, the protrusion and the inverter overlap each other.
Drive unit. A drive unit according to claim 12,
The first partial passage is formed such that a direction of the cooling air flowing through the first partial passage intersects with an axial direction of the motor.
Drive unit. A drive unit according to claim 12 or 13,
The output shaft of the reduction mechanism is provided on the protruding portion,
the output shaft does not protrude from the protruding portion to the first partial passage side or to the inverter side,
When viewed in the second direction, the inverter or the first partial passage overlaps with the output shaft.
Drive unit.

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