JP6169953B2 - Straddle-type electric vehicle - Google Patents

Description

  The present invention relates to a straddle-type electric vehicle, and more particularly, to a straddle-type electric vehicle including an electric motor that drives drive wheels using electric power from a power source.

  In an electric vehicle using an electric motor as a drive source, the electric motor is cooled using a cooling medium (see, for example, Patent Documents 1 and 2).

JP-A-5-122903 JP 2012-23837 A

  In the configuration using the cooling medium, a mechanism (refrigerant circulation mechanism) for circulating the cooling medium around or inside the electric motor is required. However, if the refrigerant circulation mechanism is reduced in size in order to suppress the increase in size of the electric vehicle, the cooling capacity cannot be ensured or the mechanism becomes complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a straddle-type electric vehicle that can suppress an increase in the temperature of an electric motor while suppressing an increase in the size of the electric vehicle. To do.

  In order to solve the above-described problem, a straddle-type electric vehicle according to an aspect of the present invention is a straddle-type electric vehicle including an electric motor that drives drive wheels using electric power from a power source. The electric motor includes a stator and a rotor that is driven to rotate about a rotation axis with respect to the stator, and a hollow space that extends on the axis of the rotation shaft and is opened on both sides in the axial direction is formed. The straddle-type electric vehicle is configured such that the hollow space communicates with the outside of the vehicle.

  According to the above configuration, air flows between the hollow space formed in the electric motor and the outside of the vehicle. For this reason, the temperature increase of the electric motor can be prevented without increasing the size of the saddle riding type electric vehicle in order to increase the capacity of the refrigerant circulation mechanism.

  One of the stator and the rotor arranged on the outer peripheral side may have at least an end surface on one end side in the axial direction of the rotating shaft inclined with respect to the axis. According to this, the surface area of at least one end surface of the rotating shaft in the axial direction can be increased without increasing the radial size of the rotating shaft in one of the stator and the rotor. Therefore, the surface area where the electric motor comes into contact with air is increased, and the temperature increase of the electric motor can be suitably prevented.

  The saddle riding type electric vehicle may include a cover that covers the rotor and the stator. Thereby, an electric motor can be protected.

  The cover may include a radiation fin extending in a radial direction of the rotary shaft between an outer peripheral surface and an inner peripheral surface of the electric motor. Thereby, the surface area which an electric motor contacts with air becomes large, and the temperature rise of an electric motor can be prevented suitably.

  The heat radiating fins may also extend to a cylindrical inner wall that forms the hollow space. Thereby, the surface area which an electric motor contacts with air becomes large, and the temperature rise of an electric motor can be prevented suitably.

  The straddle-type electric vehicle includes a communication path that is adjacent to an open end of a hollow space and communicates with the hollow space, and the communication path may be formed along an axial direction of the rotating shaft. Good. According to this, since the air outside the vehicle easily passes in the axial direction of the rotating shaft in the hollow space, the temperature increase of the electric motor can be suitably prevented.

  The above object, other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

  According to the straddle-type electric vehicle of the present invention, it is possible to suppress an increase in the temperature of the electric motor while suppressing an increase in the size of the electric vehicle.

FIG. 1 is a right side view of a saddle riding type electric vehicle according to a first embodiment of the present invention. FIG. 2 is a top view of the saddle riding type electric vehicle shown in FIG. FIG. 3 is a view of the electric motor applied to the saddle riding type electric vehicle shown in FIG. 4 is a cross-sectional view of the electric motor shown in FIG. 3 taken along the line IV-IV. FIG. 5 shows the internal structure of the electric motor shown in FIG. FIG. 6 is a sectional view showing a modification of the electric motor shown in FIG. FIG. 7 is a top view of the saddle riding type electric vehicle according to the second embodiment of the present invention. FIG. 8 is a top view of the saddle riding type electric vehicle according to the third embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted unless otherwise specified.

<First Embodiment>
First, a first embodiment of the present invention will be described. FIG. 1 is a right side view of the saddle riding type electric vehicle according to the first embodiment of the present invention. As shown in FIG. 1, the saddle riding type electric vehicle 1 includes a body frame 3 constituting a vehicle body, a front wheel 4 that is a driven wheel, and a rear wheel 5 that is a driving wheel. The vehicle body frame 3 includes a head frame 6 tilted forward and downward, a pair of left and right upper frames 7 extending rearward from the upper end portion of the head frame 6, and a pair of left and right lower frames 8 extending rearward from the lower end portion of the head frame 6. The front gusset frame 9 connects the front portion of the upper frame 7 and the front portion of the lower frame 8 in the vertical direction. Each frame 7-9 is formed of a pipe and is fixed to each other by welding.

  The head frame 6 has a pair of upper and lower front support parts 12 and 13 for supporting the front wheel 4. The front wheels 4 are connected to the front end portions of a pair of upper and lower front wheel arms 10 and 11 so as to be rotatable, and the rear end portions of the front wheel arms 10 and 11 extending rearward from the front wheels 4 are connected to the front support portions 12 and 13. Yes. Since the rear end portions of the front wheel arms 10 and 11 are connected to the front support portions 12 and 13 so as to be rotatable around a horizontal axis, the front wheel arms 10 and 11 are connected to the front support portions 12 and 13. On the other hand, it can swing up and down. The front wheels 4 are connected to the lower ends of a pair of left and right handle support members 14 that extend obliquely rearward and upward. A handle grip 15 that protrudes inward in the vehicle width direction is provided at the upper end of the handle support member 14.

  A rear frame 36 is fixed to the rear ends of the upper frame 7 and the lower frame 8 via cross frames 19 and 20. The rear portion of the rear frame 36 is rotatably connected to the front portion of the rear wheel arm 17 that supports the rear wheel 5. Accordingly, the rear wheel arm 17 can swing up and down with respect to the rear frame 36. The rear wheel arm 17 has a hollow shape. An electric motor 18 for driving is attached to the rear wheel arm 17. Further, the rear wheel arm 17 houses a power transmission mechanism (for example, a gear) (not shown) that transmits the rotational power generated by the electric motor 18 to the rear wheel 5.

  A power storage unit 22 for supplying electric power to the electric motor 18 is mounted on the body frame 3 between the front wheels 4 and the rear wheels 5. The power storage unit 22 has a cylindrical shape as a whole and has a cylindrical outer shape. The power storage unit 22 includes a power storage device 24 and an inverter 26 that is electrically connected to the power storage device 24 and disposed behind the power storage device 24. The inverter 26 and the electric motor 18 are connected by three high-voltage electric wires 27 (three-phase alternating current) extending in the front-rear direction.

  The lower frame 8 includes a frame front portion 8a that extends horizontally rearward from the head frame 6, and a frame rear portion 8b that extends rearward from the rear end of the frame front portion 8a and is inclined forward and downward along the power storage unit 22. have. A space is formed below the frame rear portion 8b of the lower frame 8, and a step member 30 for the rider to put his sole on is extended from the vehicle body frame 3 through the space. A dome-shaped cowl 31 that covers the vehicle body frame 3 from above is attached to the vehicle body frame 3. A seat 32 is disposed behind the cowl 31 and above the rear wheel arm 17 for a rider to sit on. The seat 32 is attached to the vehicle body frame 3 by a seat rail (not shown).

  FIG. 2 is a top view of the saddle riding type electric vehicle shown in FIG. As shown in FIG. 2, the structure of the saddle riding type electric vehicle 1 is symmetrical. The power storage unit 22 is disposed on a center line L0 that passes through the center in the vehicle width direction of the vehicle 1 and extends in the front-rear direction of the vehicle body in plan view. The axis of the power storage unit 22 overlaps the center line L0 in plan view. The rear wheel arm 17 including the electric motor 18 is also disposed on a center line L0 extending in the vehicle longitudinal direction in plan view. In the present embodiment, both the power storage unit 22 and the rear wheel arm 17 are formed symmetrically with respect to the center line L0 in plan view. More specifically, the front wheel 4, the front wheel arms 10, 11, the power storage unit 22, the electric motor 18, the rear wheel arm 17 (see FIG. 1), and the rear wheel 5 extend in the front-rear direction passing through the center in the vehicle width direction. Are formed symmetrically. The electric motor 18 is located directly below the seat 32. The power storage unit 22 is covered with a cowl 31 from above. The rear portion 31 b of the cowl 31 is narrower in the vehicle width direction than the front portion 31 a of the cowl 31. In plan view, the frame front portion 8a of the lower frame 8 is covered with the cowl 31, but the frame rear portion 8b of the lower frame 8 protrudes outward in the vehicle width direction from the narrow rear portion 31b of the cowl 31. . The frame rear portion 7 b of the upper frame 7 does not protrude from the cowl 31 in the vehicle width direction.

  The electric motor 18 has an axis S of a rotating shaft 42a (see FIGS. 3 to 5 described later) extending in the vehicle width direction. Two electric motors 18 are provided along the axis S of the rotating shaft 42a. These two electric motors 18 are arranged symmetrically with respect to the center line L0.

  FIG. 3 is a view of the electric motor applied to the straddle-type electric vehicle shown in FIG. 1 as viewed from the direction of the rotation axis. 4 is a cross-sectional view of the electric motor shown in FIG. 3 taken along the line IV-IV. 3 and 4 illustrate one of the two electric motors 18 (the electric motor 18 on the right side of the vehicle), the other electric motor 18 is configured similarly. As shown in FIGS. 3 and 4, the electric motor 18 includes a stator 41 and a rotor 42 that rotates around the axis S of the rotation shaft 42a with respect to the stator 41, and the axis S of the rotation shaft 42a. A hollow space 43 that extends upward and is open to both sides in the direction of the axis S is formed. The hollow space 43 is formed by a cylindrical inner wall 44 that penetrates the rotating shaft 42 a of the electric motor 18.

  The saddle riding type electric vehicle 1 is configured such that the hollow space 43 communicates with the outside of the vehicle 1. The electric motor 18 is arranged such that the end portion on the vehicle outer side (the left side in FIG. 4) of the rotation shaft 42 a in the hollow space 43 is exposed to the outside of the vehicle 1. More specifically, the outer end portion in the vehicle width direction of the rear frame 36 forms the outer end portion in the vehicle width direction of the vehicle 1 at that location. The electric motor 18 is arranged to extend outward from the outer end of the rear frame 36 in the vehicle width direction. Thereby, the hollow space 43 communicates with the outside of the vehicle 1.

  According to the above-described configuration, air travels between the hollow space 43 formed in the electric motor 18 and the outside of the vehicle 1 (indicated by an arrow AIR in FIG. 4). For this reason, the temperature increase of the electric motor 18 can be prevented without increasing the size of the saddle riding type electric vehicle 1 in order to increase the capacity of the refrigerant circulation mechanism (not shown). Furthermore, it can also be set as the structure which eliminated the refrigerant | coolant circulation mechanism.

  Even when the electric motor 18 configured as described above is employed, a cooling mechanism (not shown) for circulating a refrigerant in the electric motor 18 may be used (used together). Even in this case, since the electric motor 18 is cooled not only by the cooling mechanism but also by the hollow space 43, an appropriate cooling capacity can be obtained without excessively improving the cooling capacity of the cooling mechanism. Therefore, the temperature increase of the electric motor 18 can be prevented without increasing the size of the saddle riding type electric vehicle 1.

  Furthermore, in this embodiment, since the rotating shaft 42a of the electric motor 18 extends in the vehicle width direction, the hollow space 43 also extends in the vehicle width direction. For this reason, the inflow of the outside air into the hollow space 43 can be promoted by inclining the vehicle body when traveling on a curved road or the like. For this reason, the heat generated by the electric motor 18 during traveling can be easily released to the outside. Further, it is possible to easily release the heat in the hollow space 43 by tilting the vehicle body using the side stand when the vehicle is stopped.

  As shown in FIGS. 1 and 2, the electric motor 18 is arranged behind the lowermost position on the upper surface of the seat 32. For this reason, it is prevented that the introduction part to the hollow space 43 is blocked by a traveling rider.

  Further, the electric motor 18 is provided between the seat 32 and the step member 30 in the vertical direction. When the rider sits on the seat 32 and puts his sole on the step member 30, the rider is in a state where his knee is bent. For this reason, the electric motor 18 is disposed between the seat 32 and the step member 30 in the up-and-down direction, so that the introduction portion into the hollow space 43 is prevented from being blocked by the traveling rider. Further, the electric motor 18 may be arranged behind the step member 30. In this case, it is possible to prevent the introduction portion into the hollow space 43 from being blocked by the rider traveling more reliably. Further, when the passenger seat is disposed behind the seat 32, it is preferable that the electric motor 18 be disposed between the passenger seat and the step member for the passenger. Furthermore, in this case, it may be arranged below or behind the passenger step member.

  In the electric motor 18, the one end side in the axis S direction of the rotating shaft 42a is located outward in the vehicle width direction with respect to the other end portion. As shown in FIG. 4, at least one of the stator 41 and the rotor 42 (hereinafter referred to as one member) disposed on the outer peripheral side has at least an end face K on one end side in the axis S direction of the rotation shaft 42a. It is inclined with respect to it. According to this, it is possible to increase at least the surface area of the end surface K on one end side in the axis S direction of the rotation shaft 42a without increasing the radial size of the rotation shaft 42a in one member. Therefore, the surface area where the electric motor 18 comes into contact with air is increased, and the temperature increase of the electric motor 18 can be suitably prevented. Furthermore, since the one member is inclined inward in the axial direction as it goes radially outward, interference between the road surface and the electric motor 18 can be prevented when the vehicle body is inclined. In the present embodiment, the stator 41 is configured as one member. That is, the stator 41 is arranged on the outer peripheral side from the rotor 42.

  The saddle riding type electric vehicle 1 includes a cover 45 that covers the stator 41 and the rotor 42. Thereby, the electric motor 18 can be protected. As shown in FIG. 4, the cover 45 is fixed to the stator 41. Further, a part of the cover 45 forms an end face K on one end side in the axial direction of the rotation shaft 42a of the one member described above. Further, a part of the cover 45 extends in the direction of the axis S on the radially inner side of the rotating shaft 42a to form the above-described cylindrical inner wall 44.

  As shown in FIGS. 3 and 4, the cover 45 has radiating fins 46 extending in the radial direction of the rotating shaft 42 a across the outer peripheral surface and the inner peripheral surface of the electric motor 18. More specifically, the cover 45 includes an outer peripheral wall 45 a that covers the outer peripheral surface of the electric motor 18, a cylindrical inner wall 44 that covers the inner peripheral surface of the electric motor 18 and forms the hollow space 43, and a rotating shaft 41 a of the inner wall 44. A ring-shaped outer member 45b extending radially outward from one end in the axial line S direction, and a ring-shaped inner member 45c extending radially inward from the other end in the axis S direction of the rotation shaft 41a of the outer peripheral wall 45a. Prepare. Therefore, the outer peripheral surface of the electric motor 18 is formed by the outer peripheral wall 45 a and the inner peripheral surface is formed by the inner wall 44. The inner wall 44 has a cylindrical shape. The center of the cylindrical shape coincides with the axis S of the rotation shaft 42a. The cover 45 is fixed to a stator body 41a of the stator 41 described later.

  Thus, by forming a part of the cover 45 as the heat radiating fins 46, the surface area of the electric motor 18 that comes into contact with air is increased, and the temperature increase of the electric motor 18 can be suitably prevented. A plurality of the radiating fins 46 are provided with a gap in the circumferential direction of the rotating shaft 42a. The hollow space 43 and the outside are configured to communicate with each other through a gap between the plurality of heat radiation fins 46.

  The heat radiating fins 46 also extend to the cylindrical inner wall 44 that forms the hollow space 43. That is, the radiation fins 46 include a radially extending portion 46a extending in the radial direction of the rotating shaft 42a, and an axially extending portion 46b extending in the axial direction of the rotating shaft 42a from the radially inner end portion of the radially extending portion 46a. And. Thereby, the surface area which the electric motor 18 contacts with air becomes large, and the temperature rise of the electric motor 18 can be prevented suitably.

  The radiating fins 46 and the outer member 45b of the cover 45 are formed of a material having a high thermal conductivity (for example, a metal material such as aluminum). Thereby, the cooling efficiency at the time of the heat which generate | occur | produced in the electric motor 18 is transmitted to the radiation fin 46 and the outer member 45b from the hollow space 43 can be made high. Thus, the cooling efficiency can be increased by using the cover 45 as a heat radiating member. Moreover, since the surface area which functions as a heat radiating member becomes large by providing the some heat radiating fin 46 in addition to the outer side member 45b, cooling efficiency can be made still higher.

  FIG. 5 is a diagram showing an internal structure of the electric motor shown in FIG. FIG. 5 shows a state where the cover 45 is removed in FIG. As shown in FIGS. 4 and 5, the stator 41 has a plurality of first magnets 47 arranged in the circumferential direction of a virtual circle C perpendicular to the rotation shaft 42 a. The plurality of first magnets 47 are arranged at equal intervals. The rotor 42 has a plurality of second magnets 48 disposed to face the plurality of first magnets 47. The plurality of second magnets 48 are arranged at equal intervals. In the present embodiment, nine first magnets 47 and nine second magnets 48 are provided. The number of the 1st magnet 47 and the 2nd magnet 48 is not restricted to this, It sets suitably suitably.

  At least one of the first magnet 47 and the second magnet 48 is configured as an electromagnet. In the present embodiment, the first magnet 47 provided on the stator 41 is configured as an electromagnet. The plurality of first magnets 47 have conductivity, and have a plurality of extending members (teeth) 47 a extending in the radial direction so as to face the second magnet 48. Further, a coil 47b is wound around the plurality of extending members 47a.

  The second magnet 48 is configured as a permanent magnet. The rotor 42 has a plurality of (nine) arm portions 42b extending in the axis S direction from one end portion in the axis S direction of the rotor main body configured as the rotation shaft 42a, and at the tip of the arm portion 42b. A second magnet 48 that is a permanent magnet is attached in a direction facing the first magnet 47. For example, a neodymium magnet or the like can be used as the permanent magnet.

  The second magnet 48 configured as a permanent magnet may be configured on the surface of the rotor 42 as shown in FIG. 4 (so-called SPM structure), but is instead disposed inside the rotor 42. It is good also as a structure (so-called IPM structure). Further, both the first magnet 47 and the second magnet 48 may be electromagnets. Further, the first magnet 47 may be a permanent magnet and the second magnet 48 may be an electromagnet. Furthermore, in the present embodiment, the stator 41 is disposed on the outer peripheral side from the rotor 42, but instead, the rotor 42 may be disposed on the outer peripheral side from the stator 41.

  In the present embodiment, the plurality of first magnets 47 are arranged in a state inclined at a predetermined angle with respect to the axis S of the rotation shaft 42a. More specifically, in a cross-sectional view passing through the axis S and the end surface K on one end side in the axis S direction of the rotating shaft 42a in the stator 41 where the tip ends of the plurality of extending members 47a (winding portions of the coil 47b) are one member. It is comprised so that it may become substantially parallel. Each of the plurality of extending portions 47a is fixed to the stator main body 41a at the base end portion, and rotates toward the one end side in the axis S direction from the first portion 47a1 extending in the axis S direction and the distal end of the first portion 47a1. 2nd part 47a2 located in the radial direction center side of the axis | shaft 41a. The coil 47b is wound around at least a part of the second portion 47a2.

  The plurality of arm portions 42b in the rotor 42 are each formed in a substantially J shape. The distal end portions of the plurality of arm portions 42 are configured to be positioned radially outward of the rotation shaft 41a from the one end side (the vehicle width direction outer side) toward the distal end in the axis S direction. Accordingly, the distal end portions of the plurality of arm portions 42b, the second magnet 48, and the extending member 47a (second portion 47a2) constituting the first magnet 47 can be arranged on a straight line.

  According to the said structure, the 2nd magnet 48 which is an electromagnet is arrange | positioned in the position inclined with respect to the axis S of the rotating shaft 42a. Thereby, the length of the 2nd part 47a2 in the 1st magnet 47 can be lengthened, without changing the magnitude | size of the rotating shaft 42a of the electric motor 18 in the radial direction. That is, the number of turns of the coil 47b wound around the first magnet 47 can be increased, and the magnetic force of the first magnet 47 can be improved. According to the above configuration, instead of improving the magnetic force of the first magnet 47, the size of the electric motor 18 in the radial direction can be reduced without changing the magnetic force of the first magnet 47. Further, the surface area of the electric motor 18 can be increased without changing the size of the electric motor 18 in the radial direction, and the cooling efficiency of the electric motor 18 can be increased. Furthermore, the ratio of the length in the axis S direction to the length in the radial direction of the rotation shaft 42a of the rotor 42 increases (the surface area of the inner wall 44 forming the hollow space 43 increases). Therefore, the cooling efficiency by introducing the outside air into the hollow space 43 can be increased.

  In the rotor 42, the rotor main body constituting the rotary shaft 42 a is pivotally supported on the stator main body 41 a of the stator 41 via a bearing 49. An output mechanism that outputs the rotational power of the rotor 42 is provided at the other end of the rotating shaft 42a in the direction of the axis S (the side opposite to the mounting portion of the second magnet 48). For example, as shown in FIG. 4, the output mechanism is an output gear 50 that is coaxially fixed to the rotor 42. The output gear 50 constitutes a part of a power transmission mechanism that transmits the rotational power generated by the electric motor 18 to the rear wheel 5. The output gear 50 is provided with a communication hole 50 a adjacent to the open end on the other end side in the axis S direction of the hollow space 43 and communicating with the hollow space 43. That is, the output gear 50 is formed in a ring shape having a communication hole 50a at the center. The output gear 50 is accommodated in the rear wheel arm 17. The rear wheel arm 17 and the cover 45 of the electric motor 18 may be integrally formed. Further, the cover 45 or the rear wheel arm 17 of the electric motor 18 is pivotally supported on the rear frame 36 via a bearing 51 so that the electric motor 18 and the rear wheel arm 17 can rotate with respect to the rear frame 36. Yes. The bearing 51 shares the axis S with the rotating shaft 42 a of the electric motor 18. That is, the axis of the swing shaft of the rear frame 36 coincides with the axis S of the rotating shaft 42 a of the electric motor 18. Thereby, the electric motor 18 and the rear wheel arm 17 are configured to be swingable about the axis S of the rotation shaft 42 a of the electric motor 18 with respect to the rear frame 36. At this time, in the electric motor 18, both the stator 41 and the rotor 42 swing with respect to the rear frame 36.

  In the above embodiment, the number of the first magnets 47 and the number of the second magnets 48 are the same. However, the present invention is not limited to this, and can be applied to a configuration in which the first magnet 47 is larger than the second magnet 48 or a configuration in which the first magnet 47 is smaller than the second magnet 48. Further, the plurality of arm portions 42 b in the rotor 42 are provided by the number of the second magnets 48 provided in the rotor 42. That is, one second magnet 48 is provided on one arm portion 42b. However, the present invention is not limited to this, and a plurality of second magnets 48 may be provided in each of one or a plurality of arm portions 42b.

  As described above, in the present embodiment, the two electric motors 18 are arranged symmetrically with respect to the center line L0 of the saddle riding type vehicle 1. 3 to 5 show the electric motor 18 on the right side of the vehicle. Therefore, the electric motor 18 on the left side of the vehicle has a shape that is a left-right reversal of FIGS. The output gear 50 is also attached to each of the two electric motors 18 (has two output gears 50), but one output gear common to the left and right electric motors 18 may be used. In addition, when two output gears 50 are provided, the two output gears 50 may be connected and interlocked, or may be cut off from each other to enable independent left and right drive.

<Modification of First Embodiment>
Next, a modification of the first embodiment will be described. FIG. 6 is a cross-sectional view showing a modification of the electric motor shown in FIG. In addition, about the structure similar to the said 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. The electric motor 18M in the present modification is different from the electric motor 18 of the first embodiment in that the cross-sectional area perpendicular to the axis S at the vehicle outer side end OE of the hollow space 43 is as shown in FIG. Is configured to be larger than the cross-sectional area perpendicular to the axis S at the vehicle inner side end portion IE in the axis S direction. More specifically, the cylindrical inner wall 44M forming the hollow space 43 is configured such that the cross-sectional area perpendicular to the axis S increases toward the vehicle outer side in the axis S direction in at least a partial region in the axis S direction. Has been. In FIG. 6, a cylindrical inner wall 44M extends from the vehicle inner side end portion IE in the axis S direction toward the vehicle outer side in the axis S direction, and has a constant diameter portion 44a having a constant inner diameter, and an axis S of the constant diameter portion 44a. And an enlarged diameter portion 44b having an inner diameter that increases from the directional vehicle outer side end portion CP toward the axial direction vehicle outer end portion OE.

  Also in this modification, the cylindrical inner wall 44M has a circular cross section perpendicular to the axis S. Therefore, the inner peripheral upper wall of the enlarged diameter portion 44b of the hollow space 43 is formed so as to incline upward toward the outside of the vehicle in the axis S direction. Thereby, the heat generated by the electric motor 18B is likely to escape to the outside. Furthermore, the inner peripheral lower wall of the enlarged diameter portion 44b of the hollow space 43 is formed so as to be inclined downward toward the vehicle outward in the axis S direction. Thereby, even when water enters the hollow space 43, it is easily discharged to the outside.

  In addition, in this modification, although it was set as the structure which provided the enlarged diameter part 44b in a part of inner wall 44M, you may comprise so that the whole inner wall 44M may become an enlarged diameter part. That is, the inner wall 44M may be configured such that its inner diameter increases from the axial S direction vehicle inner end portion IE to the axial S direction vehicle outer end portion OE.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 7 is a top view of the saddle riding type electric vehicle according to the second embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 7, the saddle riding type electric vehicle 101 of the present embodiment is an electric motorcycle. The vehicle 101 includes a front wheel 104 that is a driven wheel and a rear wheel 105 that is a driving wheel.

  Also in this embodiment, the electric motor 18 is attached to a vehicle body frame (not shown) below the seat 32. The electric motor 18 is disposed behind the step member 30. Thereby, it is prevented that the introduction part to the hollow space 43 is blocked by a traveling rider. Further, two electric motors 18 are arranged in the direction of the axis S of the rotating shaft. The axis S of the rotating shaft of the electric motor 18 is along the vehicle width direction.

  Further, the saddle riding type electric vehicle 101 is provided with a communication path 52 adjacent to the open end of the hollow space 43 of the electric motor 18 and communicating with the hollow space 43. The path of the communication path 52 is formed along the axis S direction of the rotation axis. According to this, since the air outside the vehicle 101 easily passes in the direction of the axis S of the rotating shaft in the hollow space 43, the temperature increase of the electric motor 18 can be suitably prevented. Further, by providing the communication passage 52 that connects the outside and the hollow space 43 of the electric motor 18, even when the electric motor 18 is provided inside the vehicle 101, it is possible to cause the air to flow appropriately. .

  Although the shape of the front-end | tip part of the communicating path 52 is not specifically limited, For example, as shown in FIG. 6, you may have a shape along the shape of the exterior (a cowl etc.) of the vehicle 101. As shown in FIG. Moreover, the front-end | tip part of the communicating path 52 may have a shape which is located in a vehicle width direction inner side as it goes ahead of a vehicle in planar view. Thereby, it becomes easy to take in air from the front, and traveling wind generated during traveling can be easily introduced into the hollow space 43 via the communication path 52.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 8 is a top view of the saddle riding type electric vehicle according to the third embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 8, the saddle riding type electric vehicle 201 of the present embodiment is an electric motorcycle. The vehicle 201 includes a front wheel 204 that is a driven wheel and a rear wheel 205 that is a driving wheel.

  Also in this embodiment, the electric motor 18 is attached to a vehicle body frame (not shown) below the seat 32. Further, the electric motor 18 is arranged such that the axis S of the rotation axis is along the vehicle longitudinal direction. The axis S of the rotating shaft of the electric motor 18 is located on a center line L0 that passes through the center in the vehicle width direction of the vehicle 201 and extends in the longitudinal direction of the vehicle body in plan view.

  The straddle-type electric vehicle 201 includes communication passages 53 f and 53 r that are adjacent to the open end of the hollow space 43 of the electric motor 18 and communicate with the hollow space 43. The communication paths 53f and 53r have at least part of their paths formed along the axis S direction of the rotation shaft. According to this, since the air outside the vehicle 201 easily passes in the direction of the axis S of the rotating shaft in the hollow space 43, the temperature increase of the electric motor 18 can be suitably prevented. Further, by providing the communication passages 53f and 53r that connect the outside and the hollow space 43 of the electric motor 18, even when the electric motor 18 is provided inside the vehicle 201, air can be suitably routed. Can do.

  In the present embodiment, the communication path 53f provided on the front side of the electric motor 18 has a curved portion in order to communicate with the outside. Further, the front communication passage 53f is configured such that an end portion (air intake port from the outside) on the vehicle exterior side faces the front of the vehicle. Thereby, it becomes easy to take in air from the front, and traveling wind generated during traveling can be easily introduced into the hollow space 43 via the communication path 52. The communication path 53r provided on the rear side of the electric motor 18 is along the axis S direction over the entire path.

  Rotational power output from the electric motor 18 is transmitted to the rear wheel 205 via the power transmission mechanism 54. The power transmission mechanism 54 converts the rotation around the axis S along the vehicle longitudinal direction by the electric motor 18 into rotation along the vehicle width direction via a transmission direction conversion mechanism (not shown) such as a bevel gear. It is configured to transmit to the wheel 205.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description is to be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the preferred mode of carrying out the invention. The details of the structure and / or function can be substantially changed without departing from the spirit of the invention. For example, the constituent elements in the plurality of embodiments and the modified examples may be arbitrarily combined.

  In the above embodiment and the modification, the case where the shape of the cross section perpendicular to the axis S of the rotation axis of the hollow space 43 of the electric motor 18 is circular has been described, but the present invention is not limited to this. For example, the cross-sectional shape of the hollow space 43 may have a polygonal shape greater than or equal to a triangle. Similarly, the cross-sectional shape of the communication passages 52 and 53 adjacent to the hollow space 43 is appropriately selected.

  In the above-described embodiment, the configuration in which the hollow space 43 of the electric motor 18 is opened only on both sides in the axial direction has been described. However, a passage communicating with the outside of the vehicle 1 is formed in the middle portion of the hollow space 43 in the axial direction. May be. In this case, it is possible to generate a flow of air that flows from the axially intermediate portion of the hollow space 43 to both sides in the axial direction. Further, in order to promote the air flow in the hollow space 43 in any one of the axial directions, the shapes and / or areas of the openings on both sides in the axial direction of the hollow space 43 may be different from each other. For example, the area of the opening on one end side in the axial direction of the hollow space 43 may be larger than the area of the opening on the other end side. Thereby, the flow of air from the axial direction one end side to the axial direction other end side can be promoted.

  Moreover, in the said embodiment, although the structure which used the permanent magnet 48 for the hollow space 43 side (rotor 42) of the electric motor 18 among the stator 41 and the rotor 42 was demonstrated, out of a stator and a rotor. An electromagnet having a coil may be disposed on the hollow space 43 side of the electric motor 18. In this case, when the electric wire constituting the coil generates heat when energized, the coil is brought close to the hollow space 43, whereby heat radiation is promoted by the air passing through the hollow space 43.

  Moreover, in the said embodiment, although the axis line S of the rotating shaft of the electric motor 18 demonstrated the aspect along the vehicle width direction, and the aspect along the vehicle front-back direction, it is not restricted to these aspects. For example, the axis line S of the rotating shaft may be along the vehicle vertical direction. Furthermore, you may arrange | position the electric motor 18 so that the axis line S may face diagonally with respect to a vehicle. In addition, the presence / absence, shape, size, and the like of the communication path can be appropriately set according to the configuration of the saddle riding type electric vehicle in which the electric motor 18 is installed. Moreover, in the said embodiment, although the structure using one or two electric motors 18 was demonstrated, the structure provided with more electric motors 18 may be sufficient. When two or more electric motors 18 are used, the hollow spaces 43 of the electric motors 18 may not necessarily communicate with each other as in the above-described embodiment. Moreover, when it has two or more electric motors, it is not always necessary to have a configuration in which the hollow space 43 is provided for all electric motors as in the above embodiment. In other words, at least one of the plurality of electric motors is configured as in the above embodiment, and the effects described in the present specification are achieved.

  In the above embodiment, the configuration in which the front wheels 4 are supported by the pair of upper and lower front wheel arms 10 and 11 attached to the vehicle body frame 3 has been described. However, the straddle-type electric vehicle to which the present invention is applied is described here. Not limited. For example, a straddle-type electric vehicle may have a structure in which front wheels are indicated by a front fork supported by a body frame.

  INDUSTRIAL APPLICABILITY The present invention is useful in a straddle-type electric vehicle for suppressing an increase in the temperature of an electric motor while suppressing an increase in the size of the electric vehicle.

1,101,201 Saddle-type electric vehicle 5,105,205 Rear wheel (drive wheel)
18, 18M Electric motor 22 Power storage unit (power supply)
41 Stator 42 Rotor 42a Rotating shaft 43 Hollow space 44 Inner wall 45 Cover 45a Outer peripheral wall 46 Radiation fin 52, 53 Communication path K End face on one end side in axial direction

Claims (4)

A straddle-type electric vehicle including an electric motor that drives driving wheels using electric power from a power source,
The electric motor includes a stator and a rotor that rotates around a rotation axis with respect to the stator, and a hollow space that extends on the axis of the rotation shaft and is open on both sides in the axial direction is formed. Configured to
The saddle riding type electric vehicle is configured such that the hollow space communicates with the outside of the vehicle ,
One of the stator and the rotor arranged on the outer peripheral side is a straddle-type electric vehicle in which at least an end surface on one end side in the axial direction of the rotation shaft is inclined with respect to the axis . A straddle-type electric vehicle including an electric motor that drives driving wheels using electric power from a power source,
The electric motor includes a stator and a rotor that rotates around a rotation axis with respect to the stator, and a hollow space that extends on the axis of the rotation shaft and is open on both sides in the axial direction is formed. Configured to
The saddle riding type electric vehicle is configured such that the hollow space communicates with the outside of the vehicle,
A cover that covers the rotor and the stator;
The straddle-type electric vehicle , wherein the cover has a heat radiation fin extending in a radial direction of the rotary shaft between an outer peripheral surface and an inner peripheral surface of the electric motor. The straddle-type electric vehicle according to claim 2 , wherein the radiating fin extends to a cylindrical inner wall that forms the hollow space. A straddle-type electric vehicle including an electric motor that drives driving wheels using electric power from a power source,
The electric motor includes a stator and a rotor that rotates around a rotation axis with respect to the stator, and a hollow space that extends on the axis of the rotation shaft and is open on both sides in the axial direction is formed. Configured to
The saddle riding type electric vehicle is configured such that the hollow space communicates with the outside of the vehicle,
Adjacent to the open end of the hollow space, comprising a communication passage communicating with the hollow space,
The communication path is a straddle-type electric vehicle in which the path is formed along the axial direction of the rotating shaft .

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