Saddle-type electric vehicle

Abstract

The present invention achieves a lower floor design while using a battery case as a part of a vehicle body frame, and is capable of ensuring a stroke amount for a rear suspension.　Provided is saddle-type electric vehicle comprising: a swing arm (16) that rotatably supports a rear wheel (12); a battery case (33) that is provided between a front wheel (14) and the rear wheel (12) as at least a portion of a vehicle body frame (11); and a drive battery (40) that is accommodated in the battery case (33). One end (17a) of a link-type rear suspension (17) that suspends the swing arm (16) is supported by the battery case (33).

Description

Straddle-type electric vehicle

[0001] The present invention relates to a straddle-type electric vehicle.

[0002] In recent years, efforts to achieve a low-carbon society or a decarbonized society have become active, and research and development on electrification technologies have been conducted in vehicles as well to reduce CO2 emissions and improve energy efficiency. Among straddle-type electric vehicles composed of multiple modules, there is one that uses a battery case for housing a driving battery 40 as part of the vehicle body frame (see, for example, Patent Document 1).

[0003] International Publication No. 2017 / 130040

[0004] By the way, in technologies related to electrification technologies, for example, in the case of a step-through type vehicle, while using a battery case as part of the vehicle body frame, it is desirable to lower the floor to improve habitability. Even in such an electric vehicle, it is necessary to ensure a sufficient stroke amount of the rear suspension. The present application aims to provide a straddle-type electric vehicle that can achieve a lower floor while using a battery case as part of the vehicle body frame and ensure the stroke amount of the rear suspension. Since a link-type rear suspension can be laid on the rear part of the battery case, the external appearance exposure of the rear suspension is suppressed, and by improving the external appearance, reducing weight, and concentrating mass, the running performance is optimized, the lifetime energy consumption due to reduction of running power consumption is suppressed, and ultimately it contributes to the mitigation or reduction of the impact of climate change.

[0005] Provided is a straddle-type electric vehicle having a swing arm that rotatably supports a rear wheel, a battery case provided at least as part of the vehicle body frame between a front wheel and the rear wheel, and a driving battery housed in the battery case, wherein one end of a link-type rear suspension for suspending the swing arm is supported by the battery case.

[0006] According to the present invention, the battery case can be used as part of the vehicle frame while lowering the floor and ensuring sufficient stroke for the rear suspension. Furthermore, by concentrating the rear suspension, pivot axis, and at least a portion of the rear frame at the rear of the battery case, the vehicle components can be made lighter, and consequently, the vehicle weight can be reduced. In addition, by suspending the rear suspension near the center of the vehicle, weight reduction and mass centralization can be achieved.

[0007] Figure 1 is a side view of a saddle-type electric vehicle according to an embodiment of the present invention. Figure 2 is a side view of the battery case along with its surrounding components. Figure 3 is a top view of the battery case along with its surrounding components. Figure 4 is a diagram showing the battery case, rear wheel module, rear module, and front module. Figure 5 is a side view of the battery case. Figure 6 is a top view of the battery case. Figure 7 is a bottom view of the battery case. Figure 8 is a perspective view showing the battery case rear connection structure along with its surrounding components. Figure 9 is a side view showing the rear suspension and battery case rear connection structure along with its surrounding components. Figure 10 is a diagram showing a cross-section at the center of the vehicle width of Figure 9. Figure 11 is a diagram showing a cross-section at the center of the vehicle width when the rear suspension is compressed. Figure 12 is an enlarged view of the main part of the battery case rear connection structure. Figure 13 is a side view showing the battery case front connection structure along with its surrounding components. Figure 14 is a top view showing the battery case front connection structure along with its surrounding components. Figure 15 is a front view showing the battery case front connecting structure along with its surrounding components.

[0008] Embodiments of the present invention will be described below with reference to the drawings. In the description, directions such as front, back, left, right, and up and down refer to directions relative to the vehicle body unless otherwise specified. In each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the top of the vehicle body, and the symbol LH indicates the left side of the vehicle body.

[0009] [Embodiment] [1. Overall Vehicle Configuration] Figure 1 is a side view of a saddle-type electric vehicle 10 according to an embodiment of the present invention. Hereinafter, the saddle-type electric vehicle 10 will be referred to as "electric vehicle 10". As shown in Figure 1, the electric vehicle 10 is an electric motorcycle comprising a body frame 11, a drive motor 13 that drives the rear wheel 12 which is the drive wheel, a pair of left and right front forks 15 that steerably support the front wheel 14, a swing arm 16 that supports the rear wheel 12, a rear suspension 17 that suspends the swing arm 16, a seat 18 on which the rider sits, a luggage box 19 located below the seat 18, a grab rail 20, and a body cover 21 that covers the body frame 11.

[0010] The electric vehicle 10 is a saddle-type vehicle in which the rider sits straddling the seat 18, and is a step-through type scooter vehicle having a low floor section 10f in the center of the front and rear of the vehicle body.

[0011] As shown in Figure 1, the vehicle frame 11 comprises a head pipe 31 located at the front of the vehicle, a front frame 32 extending downward from the head pipe 31, a battery case 33 which is part of the vehicle frame 11, and a rear frame 34 located at the rear of the vehicle. The head pipe 31 supports a pair of left and right front forks 15 and a steering handle 23 via a steering shaft 31s (Figure 3), thereby supporting the front wheels 14 so that they can be steered left and right.

[0012] The front frame 32 is a frame that connects the head pipe 31 and the battery case 33, and has a pair of left and right frames that extend from the head pipe 31 to the left and right and downward and rearward. The lower end of each front frame 32 is connected to the front of the battery case 33. The pair of left and right front frames 32 are formed in a symmetrical shape with respect to the vehicle width center LC. Furthermore, since there is space between the pair of left and right front frames 32, it is possible to arrange control devices such as an ECU that controls the electrical components of the electric vehicle 10, and lead-acid batteries used for auxiliary batteries, etc.

[0013] As shown in Figure 1, the head pipe 31 and front frame 32 are covered by the front cowl 21a and leg shield 21b, which are part of the vehicle body cover 21. The rear frame 34 is the frame at the rear of the vehicle body and supports the rear components of the vehicle body, including the seat 18 and luggage box 19. The rear frame 34 has a pair of left and right frames that extend upward from the rear of the battery case 33 with a gap between them. The pair of left and right rear frames 34 are formed in a symmetrical shape with respect to the vehicle width center LC. Each rear frame 34 is covered by a rear side cover 21c, which is part of the vehicle body cover 21.

[0014] Figure 2 is a side view of the battery case 33 along with its surrounding components. Figure 3 is a top view of the battery case 33 along with its surrounding components. As shown in Figures 2 and 3, the battery case 33 is a hollow, rectangular box shape that extends in the front-to-back and left-to-right directions and has a relatively small thickness compared to these dimensions, housing the drive battery 40 inside. The battery case 33 is made of a rigid material such as metal, and its high rigidity satisfies the strength required for the frame between the front frame 32 and the rear frame 34.

[0015] In this configuration, the battery case 33 includes a rear suspension connecting portion 41 to which one end 17a of the rear suspension 17 is connected, a swing arm connecting portion 42 that supports the pivot shaft 36 of the swing arm 16, a pair of left and right rear frame connecting portions 43 to which parts of a pair of left and right rear frames 34 are connected, and a pair of left and right front frame connecting portions 44 to which parts of a pair of left and right front frames 32 are connected. In each figure, the one end 17a of the rear suspension 17 and the pivot shaft 36, etc., are indicated by their axis lines with reference numerals.

[0016] The rear suspension connecting portion 41, the swingarm connecting portion 42, and the rear frame connecting portion 43 are provided at the rear of the battery case 33. The area of ​​the connecting structure Sr related to the rear of the battery case 33 is shown in Figures 2 and 3 and is referred to as the "rear battery case connecting structure Sr". The front frame connecting portion 44 is provided at the front of the battery case 33. The area of ​​the connecting structure Sf related to the front of the battery case 33 is shown in Figures 2 and 3 and is referred to as the "front battery case connecting structure Sf".

[0017] Figure 4 shows the swingarm 16, rear frame 34, and front frame 32 separated from the swingarm connecting portion 42, rear frame connecting portion 43, and front frame connecting portion 44 of the battery case 33, respectively. As shown in Figure 4, the drive system components, including the drive motor 13, rear wheel 12, and motor case cover 45, are attached to the swingarm 16, thereby forming a rear wheel module 50 consisting of a unit swing type drive device.

[0018] Furthermore, the rear module 51 is formed by attaching rear body components, including the seat 18 and luggage box 19, to the rear frame 34. Also, the front module 52 is formed by attaching front body components, including the front wheel 14, front fork 15, head pipe 31, and steering system, including the handlebars 23, to the front frame 32.

[0019] As shown in Figure 4, the electric vehicle 10 is formed in a modular structure in which the rear wheel module 50, rear module 51, and front module 52, each consisting of a unit swing type drive unit, can be separated from the battery case 33.

[0020] [2. Battery Case 33] Figure 5 is a side view of the battery case 33. Figure 6 is a top view, and Figure 7 is a bottom view. As shown in Figures 5 to 7, the battery case 33 has a case portion 61 that houses the drive battery 40 and a lid member 62 that closes the case portion 61 from below. As shown in Figure 5, the height of the case portion 61, Ha, is set to be greater than the height of the lid member 62, Hb. The interface Mk between the case portion 61 and the lid member 62 is parallel to the top surface Mu and the bottom surface Mq of the battery case 33.

[0021] The case portion 61 has a pair of left and right side plates 61a extending in the front-rear direction with a gap between them, a front plate 61b bridging the front ends of the pair of left and right side plates 61a, and a rear plate 61c bridging the rear ends of the pair of left and right side plates 61a. Furthermore, the case portion 61 has a top plate 61d that covers the space enclosed by the pair of left and right side plates 61a, the front plate 61b, and the rear plate 61c from above, forming a rectangular box shape that opens downwards. These are formed from a rigid material such as metal, giving the case portion 61 high rigidity. For example, the side plates 61a extending linearly in the front-rear direction make the battery case 33 strong against loads acting in the front-rear direction, and the front plate 61b and rear plate 61c extending in the vehicle width direction make the battery case 33 strong against loads acting in the vehicle width direction.

[0022] Ribs extending in the front-to-back direction are formed on the upper surface of the top plate portion 61d at intervals in the vehicle width direction. These ribs increase the surface area of ​​the battery case 33, enabling efficient heat dissipation of the drive battery 40. Furthermore, these ribs increase the rigidity of the top plate portion 61d, thereby further increasing the rigidity of the battery case 33. Female screw portions 63 (Figure 7) for fixing the lid member 62 are formed at intervals on the left and right pair of side plates 61a, the front plate portion 61b, and the rear plate portion 61c. The number and position of the female screw portions 63 can be set as appropriate.

[0023] A lid member 62 is attached to cover the opening formed by the left and right side plates 61a, the front plate 61b, and the rear plate 61c from below. The lid member 62 is fixed to the case portion 61 by fastening a plurality of screw members 70 to each female screw portion 63 (Figure 7) from below. The drive battery 40 inside the case portion 61 is surrounded by the case portion 61 and the top plate portion 61d, thus enabling proper protection of the drive battery 40. The lid member 62 is made of a rigid material such as metal, which contributes to improving the rigidity of the battery case 33.

[0024] As shown in Figure 6, the rear suspension connecting portion 41 is integrally provided with the top plate portion 61d, located at the top of the battery case 33 and in the center of the battery case 33 in the vehicle width direction, and is a pair of left and right plate-like members that protrude upward from the top plate portion 61d. The pair of left and right members constituting the rear suspension connecting portion 41 have holes 41h (Figure 5) that penetrate in the vehicle width direction. One end 17a of the rear suspension 17 is rotatably supported in each hole 41h. The left side of the rear suspension connecting portion 41 in the vehicle width direction has a first opening 61k1 for arranging a charging connector that is connected to the drive battery 40 and to a power transmission cable extending from the charging port (not shown) of the drive battery 40. On the other hand, the right side of the rear suspension connecting portion 41 in the vehicle width direction has a second opening 61k2 for arranging a signal line extending from the drive battery 40. Furthermore, a DC-DC converter and other lift-up piezoelectric components are arranged below the rear suspension connecting portion 41 and in front of the rear plate portion 61c. In this embodiment, a charging connector is placed in the first opening 61k1 and the signal lines for the drive battery 40 are placed in the second opening 61k2. However, the electrical components placed in the first opening 61k1 and the second opening 61k2 can be selected as appropriate. For example, the signal lines for the drive battery 40 may be placed in the first opening 61k1 and the charging connector in the second opening 61k2. Furthermore, the number, shape, and size of the first opening 61k1 and the second opening 61k2 can be changed as appropriate.

[0025] As shown in Figure 6, the swing arm connecting portion 42 is integrally provided with the rear plate portion 61c and is formed in a cylindrical shape that extends outward in the vehicle width direction from the vehicle width center LC behind the rear plate portion 61c. The swing arm connecting portion 42 is formed in a cylindrical shape for inserting the pivot shaft 36.

[0026] As shown in Figures 5 and 6, the rear frame connecting portion 43 integrally comprises a first rear frame connecting portion 43a and a second rear frame connecting portion 43b, which are integrally provided at the rear of a pair of left and right side plate portions 61a. In the side view of the vehicle body shown in Figure 5, the first rear frame connecting portion 43a is located in front of the rear end surface Mr of the battery case 33, protruding upward from the upper surface Mu of the battery case 33, and has a hole 43h at its protruding end that extends in the vehicle width direction. The second rear frame connecting portion 43b is located below the upper surface Mu of the battery case 33 and above the lower surface Mq, and is provided closer to the rear end surface Mr of the battery case 33 than the first rear frame connecting portion 43a, and has a hole 43h that extends in the vehicle width direction.

[0027] The rear frame connecting portion 43, including the first and second rear frame connecting portions 43a and 43b, is formed as a plate-like shape that extends in the front-rear direction in a plan view, by extending from the rear upper surface to the rear rear surface of the side plate portion 61a and protruding around the side plate portion 61a. In this embodiment, the rear frame connecting portion 43 is formed as a triangular shape with corners at the top and rear in a side view of the vehicle body shown in Figure 5, with the top corner formed on the first rear frame connecting portion 43a and the rear corner formed on the second rear frame connecting portion 43b.

[0028] Although the rear frame connecting portion 43 is formed integrally with the side plate portion 61a, it may also be constructed separately from the side plate portion 61a and joined to the side plate portion 61a by a known joining method such as welding. In either case, the joining area between the rear frame connecting portion 43 and the side plate portion 61a is made a wide area that extends continuously from the rear upper surface to the rear back surface of the side plate portion 61a, as indicated by the symbol Hr in Figure 5, thereby ensuring a wide joining area between the rear frame connecting portion 43 and the battery case 33. This ensures the joining strength between the rear frame connecting portion 43 and the battery case 33, and efficiently distributes the load acting from the rear frame 34 to the battery case 33.

[0029] As shown in Figure 5, the rear plate portion 61c is provided with a push rod connecting portion 46 below the swing arm connecting portion 42, to which one end 65a of a push rod 65, which constitutes part of the link mechanism of the rear suspension 17, is connected. The push rod connecting portion 46 is integrally provided with the rear plate portion 61c and the swing arm connecting portion 42, is located behind the rear plate portion 61c, at or around the vehicle width center LC, and is formed in a cylindrical shape extending in the vehicle width direction.

[0030] As shown in Figure 5, the front frame connecting portion 44 has a first front frame connecting portion 44a and a second front frame connecting portion 44b, which are integrally provided on the front of a pair of left and right side plate portions 61a. The first front frame connecting portion 44a protrudes upward above the upper surface Mu of the battery case 33 and behind the front end surface Mf in the side view of the vehicle body shown in Figure 5, and has a hole 44h at its protruding end that extends in the vehicle width direction. The second front frame connecting portion 44b protrudes forward below the upper surface Mu of the battery case 33 and above the lower surface Mq in the side view of the vehicle body shown in Figure 5, and has a hole 44h at its protruding end that extends in the vehicle width direction. More specifically, the second front frame connecting portion 44b is formed above the interface surface Mk of the case portion 61 and the lid member 62 and below the upper surface Mu of the battery case 33, and is provided within the height-direction thickness Ha of the case portion 61.

[0031] The front frame connecting portion 44, including the first and second front frame connecting portions 44a and 44b, is formed as a plate-like shape that extends in the front-rear direction in a plan view, by extending continuously from the front upper surface to the front front of the side plate portion 61a and protruding around the side plate portion 61a. In this embodiment, the front frame connecting portion 44 is formed as a triangular shape with corners on the upper and front sides in a side view of the vehicle body shown in Figure 5, with the upper corner formed on the first front frame connecting portion 44a and the front corner formed on the second front frame connecting portion 44b.

[0032] Although the front frame connecting portion 44 is formed integrally with the side plate portion 61a, it may also be constructed separately from the side plate portion 61a and joined to the side plate portion 61a by a known joining method such as welding. In either case, the joining area between the front frame connecting portion 44 and the side plate portion 61a is made into a wide area that extends continuously from the front upper surface to the front front surface of the side plate portion 61a, as indicated by the symbol Hf in Figure 5, thereby ensuring a wide joining area between the front frame connecting portion 44 and the battery case 33. This ensures the joining strength between the front frame connecting portion 44 and the battery case 33, and efficiently distributes the load acting from the front frame 32 to the battery case 33.

[0033] [3. Rear Battery Case Connecting Structure Sr] Figure 8 is a perspective view showing the rear battery case connecting structure Sr along with its surrounding configuration. Figure 9 is a side view showing the rear suspension 17 and the rear battery case connecting structure Sr along with its surrounding configuration when the rear suspension 17 is compressed in the unloaded, ground-contacting state of the saddle-type electric vehicle 10. Figure 10 is a diagram showing the cross-section of the vehicle width center LC in Figure 9, and Figure 11 is a diagram showing the cross-section of the vehicle width center LC when the rear suspension 17 is further compressed from the unloaded, ground-contacting state of the saddle-type electric vehicle 10.

[0034] As shown in Figures 8 and 9, the rear frame 34 has fastening portions 71 that are fastened to the first rear frame connecting portion 43a. These fastening portions 71 include a first fastening portion 71a fastened by a screw member 70 to the outer side of the first rear frame connecting portion 43a in the vehicle width direction, and a second fastening portion 71b fastened by a screw member 70 to the outer side of the second rear frame connecting portion 43b in the vehicle width direction. By providing the first rear frame connecting portion 43a and the second rear frame connecting portion 43b at a distance from each other in the front-rear and up-down directions, the distance between the two fastening portions 71a and 71b of the rear frame 34 can be increased, while the space required for the placement of these fastening portions 71a and 71b can be reduced in the front-rear and up-down directions, and the weight of the fastening portion 71 can be reduced. In this embodiment, the rear frame 34 is fastened by a screw member 70, but the fastening method is not limited to a screw member.

[0035] In this embodiment, by connecting the left and right rear frames 34 to the outside in the vehicle width direction of each rear frame connecting portion 43, the internal space enclosed by the rear frames 34 can be expanded, improving the freedom of placement of rear body components such as the rear suspension 17. In this embodiment, the rear frame 34 is formed as a truss structure, but it is not limited to a truss structure, and other suitable frame structures such as pipe forms or monocoque structures made of plate materials can be adopted.

[0036] As shown in Figures 10 and 11, the rear suspension 17 includes a suspension body 67, one end 17a at the rear end of which is connected to a rear suspension connecting portion 41; a link plate 68 to which the other end 17b at the front end of the suspension body 67 is connected; and a push rod 65, one end 65a at the front end of which is connected to a push rod connecting portion 46 and the other end 65b at the rear end of which is connected to the link plate 68. The link plate 68 is also called a rod link plate.

[0037] The suspension body 67 is positioned between the left and right rear frames 34, above the upper surface Mu of the battery case 33, and inclined towards the rear and upward at an angle close to the horizontal plane. The symbol LS in Figures 10 and 11 indicates the central axis of the suspension body 67. In this configuration, the suspension body 67 is positioned in the center of the vehicle width of the battery case 33, but it is not limited to the center of the vehicle width and may be positioned around the center of the vehicle width (for example, at a position offset to either side of the vehicle width center in the vehicle width direction).

[0038] The link plate 68 connects the other end 17b of the suspension body 67, the swing arm 16, and the other end 65b of the push rod 65 to each other. More specifically, the other end 65b of the push rod 65 is rotatably connected to the link plate 68, and the other end 17b of the suspension body 67 is rotatably connected to the end of the first arm portion 68a that extends rearward and upward from the other end 65b. Furthermore, the end 68c of the second arm portion 68b that extends rearward and downward from the other end 65b of the push rod 65 is rotatably connected to the swing arm 16. By using the link mechanism consisting of the link plate 68 and the push rod 65, the stroke amount of the rear suspension 17 can be appropriately changed in relation to the stroke amount of the swing arm 16, and the stroke length of the suspension body 67 can be increased.

[0039] In this configuration, the suspension body 67 is inclined upward and rearward above the upper surface Mu of the battery case 33, and a link mechanism including the push rod 65 is positioned below the suspension body 67. This allows the rear suspension to be compactly positioned in the vertical direction while ensuring sufficient stroke for the rear suspension 17.

[0040] In Figures 10 and 11, the symbol LR indicates the central axis of the push rod 65. As shown in Figures 10 and 11, the link mechanism is configured so that the push rod 65 is maintained in an upward and rearward inclined position even when the rear suspension 17 changes state between a 1G state and a compressed state. One end 65a of the push rod 65, which is the front end, is connected to a push rod connecting part 46 which is located higher than the lower surface MQ of the battery case 33, so that the push rod 65 does not move below the battery case 33. This allows the push rod 65 to be located higher than the lower surface MQ of the battery case 33, thereby suppressing the impact on the minimum ground clearance of the electric vehicle 10.

[0041] Figure 12 is an enlarged view of the main part of the battery case rear connecting structure Sr. As shown in Figure 12, the rear suspension 17 is provided in a position that overlaps with the rear frame 34 in a side view of the vehicle body, so that the rear frame 34 can function as a guard member that protects the rear suspension 17 from the outside in the vehicle width direction. Therefore, it is possible to suppress situations in which flying debris from the side of the vehicle body affects the rear suspension 17, and for example, water exposure and dirt on the rear suspension 17 can be reduced.

[0042] Furthermore, the second rear frame connecting portion 43b, the swing arm connecting portion 42, and the push rod connecting portion 46 are located below the upper surface Mu of the battery case 33, above the lower surface Mq, and behind the rear end surface Mr, and are close to each other in the vertical direction. More specifically, the swing arm connecting portion 42 is located within the height-direction thickness Ha of the case portion 61 at the same height as, or within a range that can be considered the same as, the upper surface Mu of the battery case 33, and the push rod connecting portion 46 is located within the height-direction thickness Ha of the case portion 61 at the same height as, or within a range that can be considered the same as, the interface surface Mk between the case portion 61 and the lid portion 62 of the battery case 33. Therefore, the swing arm connecting portion 42 and the push rod connecting portion 46 are provided within the height-direction thickness Ha of the case portion 61. As a result, the battery case 33 can suppress the scattering of moisture and other debris from the front and below of the vehicle body to the second rear frame connecting portion 43b, the swing arm connecting portion 42, the push rod connecting portion 46, and their surroundings. Furthermore, the swingarm 16 and push rod 65 can be compactly arranged vertically in the space behind the battery case 33.

[0043] [3. Front Connection Structure Sf of Battery Case] Fig. 8 is a side view showing the front connection structure Sf of the battery case together with the peripheral components. Fig. 14 is a view showing the front connection structure Sf of the battery case from above together with the peripheral components. Fig. 15 is a view showing the front connection structure Sf of the battery case from the front together with the peripheral components. As shown in Figs. 13 to 15, the pair of left and right front frames 32 has a first fastening portion 81a fastened by a screw member 80 to the outside in the vehicle width direction of the first front frame connection portion 44a and a second fastening portion 81b fastened by the screw member 80 to the inside in the vehicle width direction of the second front frame connection portion 44b as fastening portions 81 fastened to the first front frame connection portion 44a. The first front frame connection portion 44a and the second front frame connection portion 44b are provided spaced apart in the front-rear and up-down directions, thereby obtaining the separation distance between the two fastening portions 81a and 81b of the front frame 32 while saving space in the front-rear and up-down directions for the space required for the arrangement of these fastening portions 81a and 81b and achieving weight reduction of the fastening portion 81. Note that the front frame 32 of the present embodiment is fastened by the screw member 80, but the fastening method is not limited to the screw member.

[0044] In the present embodiment, by connecting the left and right front frames 32 to the inside in the vehicle width direction of each front frame connection portion 44a, the protrusion of the front frame 32 to the outside in the vehicle width direction can be suppressed, and the vehicle width can be made compact. Each front frame 32 is formed in a frame shape that becomes wider in the front-rear direction as it goes toward the outside in the vehicle width direction in the plan view shown in Fig. 14. The arrows in Fig. 14 indicate the front-rear width of the front frame 32. Thereby, a wide joining area between the front frame 32 and the front plate-like member including the front frame connection portion 44 can be ensured, and a high connection strength can be ensured.

[0045] Note that the front frame 32 of the present embodiment has a reinforcing rib structure in the range from the upper and lower intermediate portions to the first and second fastening portions 81a and 81b as shown in Fig. 13, thereby increasing the frame strength while achieving weight reduction. However, it is not limited to the configuration having the reinforcing rib structure, and an appropriate frame structure can be adopted.

[0046] [4. Effects] As described above, the electric vehicle 10 of this embodiment has a battery case 33 provided between the front wheel 14 and the rear wheel 12 as part of the vehicle frame 11, as shown in Figure 5. At the rear of the battery case 33, one end 17a of the rear suspension 17, the pivot shaft 36 of the swing arm 16, and the rear frame 34 are each independently supported. With this configuration, by configuring the rear suspension 17, the swing arm 16, and the rear frame 34 as independent modules, an electric vehicle with a divided module structure can be realized in which the load acting on the battery case 33 from each module can be distributed. This makes it possible to use the battery case 33 as part of the vehicle frame 11 while suppressing the concentration of load on the battery case 33. In addition, by connecting each module to the rear of the battery case 33, it is possible to reduce the weight of the entire vehicle while maintaining high rigidity, thereby reducing raw material costs, processing costs, and lifetime energy consumption by reducing the consumption of running power, and ultimately improving energy efficiency and optimizing driving performance, which can contribute to mitigating or reducing the impact of climate change.

[0047] Furthermore, as shown in Figure 3, one end 17a of the rear suspension 17 is supported at the top of the battery case 33, in the center of the battery case 33 in the vehicle width direction. With this configuration, since the components related to the rear suspension 17 are not located below the battery case 33, it is possible to lower the floor while maintaining the minimum ground clearance. In addition, by positioning the components related to the rear suspension 17 in the center, it is possible to avoid the rear of the floor portion 10f on the battery case 33 protruding upward, thereby improving passenger comfort. Note that the same effect can be obtained even if the rear suspension 17, including the one end 17a, is supported at the top of the battery case 33, around the center of the battery case 33 in the vehicle width direction.

[0048] Further, a rear frame connection portion 43 to which at least a part of the rear frame 34 is connected is provided at the rear portion of the battery case 33. As shown in FIG. 5, the rear frame connection portion 43 includes a first rear frame connection portion 43a located above the upper surface Mu of the battery case 33 and in front of the rear end surface Mr, and a second rear frame connection portion 43b located below the upper surface Mu of the battery case 33 and on the rear end surface Mr side of the battery case 33 with respect to the first rear frame connection portion 43a. According to this configuration, the load from the rear frame 34 can be dispersed and received at a plurality of locations of the battery case 33. Further, by supporting the rear frame 34 at a high position around the upper surface Mu of the battery case 33, it is possible to reduce water ingress and contamination caused by scattered objects from below the vehicle, and to reduce the influence of contamination on the attachment and detachment of the rear frame 34 and the like.

[0049] Further, a rear suspension connection portion 41 to which one end portion 17a of the rear suspension 17 is connected is provided at the rear portion of the battery case 33. The rear suspension 17 overlaps the rear frame 34 in a side view of the vehicle body shown in FIG. 5 and the like. According to this configuration, it is possible to reduce water ingress and contamination of the rear suspension 17 caused by scattered objects from the side of the vehicle body.

[0050] Furthermore, the rear of the battery case 33 is provided with a swingarm connecting portion 42 to which the swingarm 16 is connected via a pivot shaft 36, and a pushrod connecting portion 46 to which one end 65a of the pushrod 65, which constitutes part of the link mechanism of the rear suspension 17, is connected. As shown in Figure 5, the second rear frame connecting portion 43b, the swingarm connecting portion 42, and the pushrod connecting portion 46 are provided below the upper surface Mu of the battery case 33 and above the lower surface Mq, and the swingarm connecting portion 42 and the pushrod connecting portion 46 are located behind the rear end surface Mr of the battery case 33. With this configuration, the battery case 33 can suppress the scattering of debris from the front and below of the vehicle body to the second rear frame connecting portion 43b, the swingarm connecting portion 42, the pushrod connecting portion 46, and their surroundings, thereby suppressing contamination of the connecting portions of the rear frame 34, the swingarm 16, and the pushrod 65, and preventing issues that may affect maintenance. Furthermore, since the swingarm 16 and push rod 65 can be compactly arranged vertically in the space behind the battery case 33, the design flexibility is improved.

[0051] Furthermore, a rear frame connecting portion 43 is provided at the rear of the battery case 33, to which at least a part of the rear frame 34 is connected. The rear frame connecting portion 43 extends rearward from the side of the battery case 33, and the rear frame 34 is connected to the rear frame connecting portion 43 on the outside in the vehicle width direction. With this configuration, the load from the rear frame 34 can be received by the relatively rigid side of the battery case 33, and the internal space surrounded by the rear frame 34 can be increased compared to when the rear frame 34 is fastened on the inside in the vehicle width direction.

[0052] Furthermore, since the swing arm 16 is a unit swing drive system, the load from the unit swing drive system, rear frame 34, and rear suspension 17 is distributed and received at the rear of the battery case 33. This configuration allows for weight reduction of the entire vehicle while maintaining high rigidity, and is also advantageous for mass centralization.

[0053] Furthermore, as shown in Figure 4, the rear frame 34 is a frame that supports at least the seat 18 on which the occupant sits and the luggage box 19 below the seat 18. It comprises a rear module 51 including the rear frame 34, the seat 18 and the luggage box 19, and a front module 52 including the front frame 32 which constitutes part of the vehicle body frame 11. The rear module 51 is connected to the rear of the battery case 33 via the rear frame 34, and the front module 52 is connected to the front of the battery case 33. With this configuration, an electric vehicle can be realized in which multiple modules consisting of the front module 52, the rear module 51 and the rear wheel module including the swing arm 16 can be easily separated, making it easy to replace each module or change the design.

[0054] Next, the effects of the rear suspension structure will be described. As shown in Figures 10 and 11, in this embodiment, the electric vehicle 10 has one end 17a of a link-type rear suspension 17 that suspends a swing arm 16 supported by a battery case 33, which is provided between the front wheel 14 and the rear wheel 12 as part of the vehicle frame 11. With this configuration, the battery case 33 is used as part of the vehicle frame 11, and by positioning the battery case 33 low, the floor can be lowered. By supporting one end 17a of the link-type rear suspension 17 on the battery case 33, an electric vehicle with sufficient stroke for the rear suspension 17 can be realized. Furthermore, by concentrating the rear suspension 17, pivot shaft 36, and at least a part of the rear frame 34 at the rear of the battery case 33, the vehicle components can be made lighter, and consequently the vehicle weight can be reduced. In addition, by suspending the rear suspension 17 near the center of the vehicle, weight reduction and mass centralization can be achieved. Therefore, it is possible to improve energy efficiency and optimize driving performance, and contribute to mitigating or reducing the impact of climate change.

[0055] Furthermore, the rear suspension 17 includes a suspension body 67 to which one end 17a of the rear suspension 17 is connected to the rear of the battery case 33, a link plate 68 to which the other end 17b of the suspension body 67 is connected, and a push rod 65 to which one end 65a is connected to the rear of the battery case 33 and the other end 65b is connected to the link plate 68. The suspension body 67 is inclined upward and rearward above the upper surface Mu of the battery case 33, and the push rod 65 is inclined upward and rearward from the rear of the battery case 33. With this configuration, a sufficient stroke amount of the rear suspension 17 can be secured and it can be arranged compactly in the vertical direction. In addition, since the load acting on the rear suspension 17 acts horizontally, approximately parallel to the battery case 33, vertical vibrations during driving are suppressed, improving ride comfort and reducing the vertical load acting on the drive battery. Furthermore, because the push rod 65 is inclined upward and rearward from the rear of the battery case 33, the impact on the minimum ground clearance is minimized, making it easier to secure sufficient ground clearance.

[0056] Furthermore, the rear of the battery case 33 is provided with a swingarm connecting portion 42 to which the swingarm 16 is connected via a pivot shaft 36, and a pushrod connecting portion 46 to which one end 65a of the pushrod 65, which constitutes part of the link mechanism of the rear suspension 17, is connected. The swingarm connecting portion 42 and the pushrod connecting portion 46 are located below the upper surface Mu of the battery case 33 and behind the rear end surface Mr, and are close to each other in the vertical direction. With this configuration, the battery case 33 can be used to reduce water and dirt exposure to the pivot shaft 36 and pushrod 65, etc., caused by surrounding debris.

[0057] Furthermore, the battery case 33 has a rear suspension connecting portion 41 to which one end 17a of the rear suspension 17 is connected. The battery case 33 has a case portion 61 that houses the drive battery 40 and a lid member 62 that closes the case portion 61 from below. The rear suspension connecting portion 41 is provided on the case portion 61. With this configuration, the load from the rear suspension 17 can be effectively supported by the case portion 61 of the battery case 33, which has relatively high rigidity, contributing to the stabilization of suspension performance, reduction of the number of parts, and improvement of assembly.

[0058] Next, the effects of the front structure will be described. As shown in Figure 11, the electric vehicle 10 of this embodiment has front frame connecting parts 44 on the front and top surfaces of the battery case 33, to which each of the left and right pair of front frames 32 are connected at multiple points. With this configuration, the battery case 33 can be used as part of the vehicle body frame 11, and the load acting from each front frame 32 to the battery case 33 can be distributed to the battery case 33, thereby suppressing the concentration of load from each front frame 32 to the battery case 33. Furthermore, as shown in Figure 4, by configuring a front module 52 that includes each front frame 32, it is possible to realize an electric vehicle with a divisible module structure in which the front module 52 can be easily divided while suppressing the concentration of load from the front module 52 to the battery case 33. In addition, while increasing the spacing between the multiple fastening parts 81a and 81b of the front frame 32, the space required for arranging these fastening parts 81a and 81b can be reduced in the front-to-back and up-to-down directions, and the weight of the fastening parts 81 can be reduced. Therefore, by improving energy efficiency and optimizing driving performance, it becomes possible to contribute to mitigating or reducing the impact of climate change.

[0059] The front frame connecting section 44 is not limited to a configuration in which each of the left and right front frames 32 is connected to the front and top surfaces of the battery case 33 at multiple points. For example, the front frame connecting section 44 may be configured in which each of the left and right front frames 32 is connected to the front or top surface of the battery case 33 at multiple points. In this case as well, the concentration of load from each front frame 32 to the battery case 33 can be suppressed. In other words, the front frame connecting section 44 should be configured in which each of the left and right front frames 32 is connected to at least one of the front and top surfaces of the battery case 33 at multiple points. Furthermore, the configuration is not limited to each of the left and right front frames 32 being connected to the battery case 33 at two points, but may be configured to be connected to the battery case 33 at three or more points.

[0060] Furthermore, the battery case 33 has a case portion 61 that houses the drive battery 40 and a lid member 62 that closes the case portion 61 from below, and the front frame connecting portion 44 is provided on the case portion 61. With this configuration, the load from the front frame 32 can be effectively supported by the case portion 61 of the battery case 33, which has relatively high rigidity, and excessive load concentration on the battery case 33 can be suppressed.

[0061] Furthermore, as shown in Figure 5, the front frame connecting portion 44 has a first front frame connecting portion 44a located above the upper surface Mu of the battery case 33 and behind the front end surface Mf, and a second front frame connecting portion 44b located below the upper surface Mu of the battery case 33 and in front of the front end surface Mf. With this configuration, the load from the front frame 32 can be effectively supported at positions separated from the front, rear and top and bottom of the battery case 33, thereby suppressing excessive load concentration on the battery case 33.

[0062] Furthermore, as shown in Figure 9 and other figures, the case portion 61 has a rear frame connecting portion 43 to which at least a part of the rear frame 34 is connected. With this configuration, the load from the rear frame 34 can be effectively supported by the case portion 61, which has relatively high rigidity within the battery case 33, thereby suppressing excessive load concentration on the battery case 33.

[0063] Furthermore, the front frame 32 is connected to the inside of the front frame connecting portion 44 in the vehicle width direction. With this configuration, the vehicle width can be made more compact by suppressing the outward protrusion of the front frame 32 in the vehicle width direction.

[0064] Furthermore, a rear frame connecting portion 43 is provided at the rear of the battery case 33, to which at least a part of the rear frame 34 is connected, and the rear frame 34 is connected to the rear frame connecting portion 43 on the outside in the vehicle width direction. With this configuration, the front frame 32 is connected relatively inward, and the rear frame 34 is connected relatively outward, so the load acting on the battery case 33 from each frame 32, 34 can be effectively distributed. In addition, the internal space surrounded by the rear frame 34 can be increased.

[0065] Furthermore, the height of the case portion 61, Ha, is greater than the height of the lid portion, Hb. This configuration allows for increased rigidity of the case portion 61, enabling it to effectively support the load from the front frame 32.

[0066] [Other Embodiments] The above embodiments represent only one aspect of the present invention and can be modified and applied as needed without departing from the spirit of the present invention.

[0067] For example, in the above embodiment, the case in which the present invention is applied to the electric vehicle 10 shown in Figure 1 was described, but the present invention may be applied to a different electric vehicle. The electric vehicles to which the present invention can be applied are not limited to two-wheeled vehicles, but the present invention may also be applied to saddle-type electric three-wheeled vehicles and saddle-type electric four-wheeled vehicles classified as ATVs (All Terrain Vehicles), etc.

[0068] [Configurations supported by the above embodiment] The above embodiment supports the following configurations.

[0069] (Configuration 1) A saddle-type electric vehicle having a swing arm that rotatably supports the rear wheel, a battery case provided between the front wheel and the rear wheel as at least part of the vehicle frame, and a drive battery housed in the battery case, wherein one end of a link-type rear suspension that suspends the swing arm is supported on the battery case. With this configuration, the floor can be lowered by using the battery case as part of the vehicle frame and positioning the battery case low, and an electric vehicle can be realized that has sufficient stroke for the rear suspension by supporting one end of the link-type rear suspension on the battery case. Furthermore, by concentrating the rear suspension, pivot shaft and at least a part of the rear frame at the rear of the battery case, the vehicle components can be made lighter, and consequently the vehicle weight can be reduced. Furthermore, by suspending the rear suspension near the center of the vehicle, weight reduction and mass centralization can be achieved.

[0070] (Configuration 2) The saddle-type electric vehicle according to Configuration 1, wherein the rear suspension comprises a suspension body to which one end of the rear suspension is connected to the rear of the battery case, a link plate to which the other end of the suspension body is connected, and a push rod to which one end is connected to the rear of the battery case and the other end is connected to the link plate, the suspension body is inclined upward and rearward above the upper surface of the battery case, and the push rod is inclined upward and rearward from the rear of the battery case. With this configuration, a sufficient stroke amount of the rear suspension can be secured and it can be arranged compactly in the vertical direction. In addition, since the load acting on the rear suspension acts horizontally, substantially parallel to the battery case, vertical vibrations during driving can be suppressed, improving ride comfort and reducing the vertical load acting on the drive battery. In addition, because the push rod is inclined upward and rearward from the rear of the battery case, the impact on the minimum ground clearance is minimized and it becomes easier to secure sufficient ground clearance.

[0071] (Configuration 3) The rear of the battery case is provided with a swing arm connecting portion to which the swing arm is connected via the pivot shaft, and a push rod connecting portion to which one end of a push rod constituting part of the link mechanism of the rear suspension is connected, wherein the swing arm connecting portion and the push rod connecting portion are located below the upper surface of the battery case and behind the rear end surface, and are close to each other in the vertical direction, as described in Configuration 1 or 2. With this configuration, the battery case can be used to reduce water and dirt on the pivot shaft and push rod etc. caused by surrounding debris.

[0072] (Configuration 4) The swing arm is a unit swing type drive system, as described in any one of Configurations 1 to 3 for a saddle-type electric vehicle. With this configuration, the load from the unit swing type drive system, rear frame and rear suspension is distributed and received at the rear of the battery case, making it possible to reduce the overall weight of the vehicle while maintaining high rigidity, and is also advantageous for mass centralization.

[0073] (Configuration 5) A saddle-type electric vehicle according to any one of Configurations 1 to 4, wherein the battery case has a rear suspension connecting portion to which one end of the rear suspension is connected, the battery case has a case portion for housing the drive battery and a lid member for closing the case portion from below, and the rear suspension connecting portion is provided on the case portion. With this configuration, the load from the rear suspension can be effectively supported by the case portion of the battery case which has relatively high rigidity, contributing to the stabilization of suspension performance, reduction of the number of parts and improvement of assembly.

[0074] 10 Saddle-type electric vehicle 11 Body frame 12 Rear wheel 13 Drive motor 14 Front wheel 15 Front fork 16 Swing arm 17 Rear suspension 18 Seat 19 Luggage box 20 Grab rail 21 Body cover 31 Head pipe 32 Front frame 33 Battery case 34 Rear frame 36 Pivot shaft 40 Drive battery 41 Rear suspension connection 42 Swing arm connection 43 Rear frame connection 43a First rear frame connection 43b Second rear frame connection 44 Front frame connection 44a First front frame connection 44b Second front frame connection 46 Push rod connection 50 Rear wheel module 51 Rear module 52 Front module 61 Case 62 Lid member 65 Push rod 67 Suspension body 68 Link plates 71, 81 Fastening parts 71a, 81a First fastening parts 71b, 81b Second fastening parts Mf Front end surface of battery case Mr Rear end surface of battery case Mu Top surface of battery case Mq Bottom surface of battery case

Claims

1. A saddle-type electric vehicle having a swing arm (16) that rotatably supports a rear wheel (12), a battery case (33) provided at least as part of the vehicle frame (11) between the front wheel (14) and the rear wheel (12), and a drive battery (40) housed in the battery case (33), wherein one end (17a) of a link-type rear suspension (17) that suspends the swing arm (16) is supported by the battery case (33).

2. The rear suspension (17) comprises a suspension body (67) to which one end (17a) of the rear suspension (17) is connected to the rear of the battery case (33), a link plate (68) to which the other end (17b) of the suspension body (67) is connected, and a push rod (65) to which one end (65a) is connected to the rear of the battery case (33) and the other end (65b) is connected to the link plate (68), wherein the suspension body (67) is inclined upward and rearward above the upper surface (Mu) of the battery case (33), and the push rod (65) is inclined upward and rearward from the rear of the battery case (33), as described in claim 1.

3. The rear of the battery case (33) is provided with a swing arm connecting portion (42) to which a swing arm (16) is connected via a pivot shaft (36), and a push rod connecting portion (46) to which one end (65a) of a push rod (65) that constitutes part of the link mechanism of the rear suspension (17) is connected, wherein the swing arm connecting portion (42) and the push rod connecting portion (46) are located below the upper surface (Mu) and behind the rear end surface (Mr) of the battery case (33), and are close to each other in the vertical direction, as described in claim 1.

4. The saddle-type electric vehicle according to any one of claims 1 to 3, wherein the swing arm (16) is a unit swing type drive device.

5. The saddle-type electric vehicle according to any one of claims 1 to 3, wherein the battery case (33) has a rear suspension connecting portion (41) to which one end (17a) of the rear suspension (17) is connected, the battery case (33) has a case portion (61) for housing the drive battery (40) and a lid member (62) for closing the case portion (61) from below, and the rear suspension connecting portion (41) is provided on the case portion (61).

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