Steering mechanism and electric mobility vehicle

Abstract

This steering mechanism for steering a pair of front wheels (10) of an electric mobility vehicle is configured to be capable of steering an inner wheel and an outer wheel such that a steering angle difference between an inner wheel steering angle, which is the steering angle of the inner wheel, and an outer wheel steering angle, which is the steering angle of the outer wheel, when the inner wheel steering angle is a second angle, which is any angle in a range of 90° or more, is at least five times the steering angle difference when the inner wheel steering angle is a first angle, which is any angle in a range of 40° to 45°.

Description

Steering mechanisms and electric mobility

[0001] The present invention relates to an electric mobility vehicle and its steering mechanism.

[0002] A known steering mechanism for such electric mobility vehicles includes a pitman arm, left and right knuckles, and rods connecting the pitman arm to the left and right knuckles, as disclosed in Patent Document 1, for example.

[0003] US Patent Application Publication No. 2022 / 0396309

[0004] The electric mobility vehicle has a steering mechanism for making pivot turns or super pivot turns, but the configuration of the electric mobility vehicle makes it difficult to actually have the central axes of the pair of front wheels intersect with the central axes of the pair of rear wheels at the midpoint or center between the pair of rear wheels, making it difficult to achieve smooth super pivot turns.

[0005] In view of the above circumstances, there is a demand for a steering mechanism that can realize smooth pivot turns.

[0006] One aspect of the present invention is a steering mechanism that steers a pair of front wheels of an electric mobility vehicle, and is configured to be able to steer the inner and outer wheels so that the steering angle difference between the inner wheel steering angle and the outer wheel steering angle when the inner wheel steering angle is at a first angle that is any angle in the range of 40° to 45° is five times or more when the inner wheel steering angle is at a second angle that is any angle in the range of 90° or more. Another aspect of the present invention is a steering mechanism for steering the right and left front wheels of an electric mobility vehicle, the steering mechanism including a center shaft that is rotatable at least about a first axis extending in the vertical direction and that rotates in response to operation of a steering wheel, a pitman arm fixed to the center shaft, a right knuckle that is rotatable at least about a second axis on the right side that extends in the vertical direction and that supports the right front wheel, a right knuckle arm provided on the right knuckle, and a left knuckle that is rotatable at least about the second axis on the left side that extends in the vertical direction and that supports the left front wheel. a left knuckle arm provided on the left knuckle; a right rod having one end connected to the right knuckle arm and the other end connected to the pitman arm; and a left rod having one end connected to the left knuckle arm and the other end connected to the pitman arm, wherein when the right and left front wheels are positioned at a straight-ahead steering angle for straight-ahead driving of the electric mobility, each of the rods is tilted so that the difference in height between the other end and the one end is 15 mm or more, and when the steering angle of the inner wheel is 90° or more, the difference in height is 4 mm or more smaller than at the straight-ahead steering angle.

[0007] 5 is a front view of an electric mobility vehicle according to one embodiment. FIG. 6 is a rear perspective view of the electric mobility vehicle according to the present embodiment. FIG. 7 is a side view of the electric mobility vehicle according to the present embodiment. FIG. 8 is a bottom view of the electric mobility vehicle according to the present embodiment. FIG. 9 is a plan view of a rear wheel side body of the electric mobility vehicle according to the present embodiment. FIG. 10 is a partial cross-sectional view of the rear wheel side body of the electric mobility vehicle according to the present embodiment. FIG. 11 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 12 is a bottom view of the rear wheel side body of the electric mobility vehicle according to the present embodiment. FIG. 13 is a perspective view of a main part of the rear wheel side body of the electric mobility vehicle according to the present embodiment. FIG. 14 is a rear view of the swing base of the electric mobility vehicle according to the present embodiment and a swing control unit of a first modified example. FIG. 15 is a perspective view of a main part of the rear wheel side body of the electric mobility vehicle according to the present embodiment and a swing control unit of a first modified example. FIG. 16 is a rear view of the swing base of the electric mobility vehicle according to the present embodiment and a swing control unit of a second modified example. FIG. 17 is a rear view of the swing base of the electric mobility vehicle according to the present embodiment and a swing control unit of a third modified example. FIG. 18 is a rear view of the swing base of the electric mobility vehicle according to the present embodiment and a swing control unit of a fourth modified example. FIG. 19 is a rear view of the swing base of a modified example of the electric mobility vehicle according to the present embodiment and a swing control unit of a fifth modified example. FIG. 10 is a rear view of a swing base of another modified example of the electric mobility of this embodiment and a swing control unit of a sixth modified example. FIG. 11 is a front view of the main parts of the electric mobility of this embodiment. FIG. 12 is a plan view showing the operation of the steering mechanism of this embodiment. FIG. 13 is a plan view showing the operation of the steering mechanism of this embodiment. FIG. 14 is a plan view showing the operation of the steering mechanism of this embodiment. FIG. 15 is a plan view showing the operation of the steering mechanism of this embodiment. FIG. 16 is an exploded oblique view of the main parts of the front wheel side frame of this embodiment. FIG. 17 is a cross-sectional view of the main parts of the front wheel side frame of this embodiment. FIG. 18 is a cross-sectional view of the angle adjustment mechanism of this embodiment. FIG. 19 is a cross-sectional view of the main parts of the angle adjustment mechanism of this embodiment. FIG. 19 is a front view of the main parts of the angle adjustment mechanism of this embodiment. FIG. 19 is a cross-sectional view of the main parts of the electric mobility of this embodiment. FIG. 19 is a cross-sectional view of the main parts of the electric mobility of this embodiment. FIG. 19 is a side view of the electric mobility of this embodiment in a stored state. FIG. 19 is a block diagram of the control unit of the electric mobility of this embodiment.

[0008] An electric mobility 1 according to one embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 4 , the electric mobility 1 has a mobility body 30. The mobility body 30 has a pair of front wheels 10, a pair of rear wheels 20, and a body 31 supported by the front wheels 10 and the rear wheels 20. The electric mobility 1 also has a seat unit 40 detachably attached to the mobility body 30. The electric mobility 1 of this embodiment is designed for one person to sit on the seat unit 40. Such vehicles are sometimes referred to as personal mobility vehicles. In the following description, the vehicle's fore-and-aft direction may be simply referred to as the fore-and-aft direction, and the vehicle's width direction may be simply referred to as the width direction. Furthermore, the vehicle's fore-and-aft direction and the mobility body 30 or body 31 coincide with each other, and the vehicle's width direction and the width direction of the mobility body 30 or body 31 coincide with each other. The following description will essentially be directed to the electric mobility 1 placed on a horizontal plane in an unloaded state or with a predetermined load applied. An example of a state in which a predetermined load is applied is a state in which an object or person of the allowable weight of the electric mobility 1, or an object or person of two-thirds the allowable load, is resting on the seat unit 40.

[0009] 6 and 7 , in this embodiment, the output shaft 51 of the motor 50 is connected to each of the pair of rear wheels 20, and each of the two rear wheels 20 can be driven by each of the motors 50. In this embodiment, the output shaft 51 of the motor 50 functions as the axle of the rear wheels 20. Alternatively, the driving force of the motor 50 may be transmitted to the pair of front wheels 10 via a power transmission member such as a belt, a gear, a shaft, or the axle of the rear wheels 20.

[0010] Each front wheel 10 is supported by a body 31. In this embodiment, the pair of front wheels 10 includes an axle 11, a hub 12 attached to the axle 11, and an outer peripheral member 13 provided on the outer periphery of the hub 12, the outer peripheral surface of which is formed from a material having rubber-like elasticity such as rubber or silicone. The front wheels 10 are configured to be rotatable by bearings or other bearings (not shown).

[0011] In this embodiment, each rear wheel 20 has an axle, such as the output shaft 51 of the motor 50, a hub 22 attached to the axle, and an outer peripheral member 23 provided on the outer periphery of the hub 22, the outer peripheral surface of which is formed from a material having rubber-like elasticity such as rubber or silicone.

[0012] In this embodiment, the front wheel 10 and the rear wheel 20 may be pneumatic tires or solid tires formed from a material having rubber-like elasticity all the way to the inside.

[0013] The mobility body 30 includes a front-wheel-side body 110 and a rear-wheel-side body 120 detachably connected to the front-wheel-side body 110. The front-wheel-side body 110 has a front-wheel-side frame (body frame) 111 formed so that its front end extends along the ground and to which the axles of the front wheels 10 are attached via front-wheel suspensions 160. The rear end of the front-wheel-side frame 111 is a vertical frame 111a extending upward, to the upper end of which the seat unit 40 is attached. As shown in FIG. 1 , the front-wheel suspension 160 includes a base 172 that supports the pair of front wheels 10 at both ends in the vehicle width direction via knuckles 173, 174, and a pair of springs 161 attached to the base 172. The base 172 supports the front-wheel-side frame (body frame) 111 via the pair of springs 161. In addition, the front wheel side body 110 has a front wheel side cover 110a, which is arranged to cover at least a portion of the front wheel side frame 111 and is used to protect the front wheel side frame 111, as a place to rest the feet of a passenger sitting in the seat unit 40, as a luggage storage area, as a mudguard, etc.

[0014] The front wheel side frame 111 is made of a material suitable for obtaining strength, such as metal.

[0015] 2, 4, etc., the rear-wheel-side body 120 has a rear-wheel-side frame (body frame) 121 and a rear-wheel-side cover 120a that is provided to cover at least a portion of the rear-wheel-side frame 121 and is used to protect the rear-wheel-side frame 121, as a mudguard, etc. The front-wheel-side frame 111 and the rear-wheel-side frame 121 form the entire body frame of the mobility main body 30.

[0016] The rear wheel side frame 121 is made of a material suitable for obtaining strength, such as metal.

[0017] As shown in FIG. 2 and other figures, the rear wheel side frame 121 is provided with a pair of detachable anti-tip members 126 in the width direction to prevent the electric mobility 1 from tipping backward.

[0018] As shown in FIGS. 2, 3, 5, etc., a rechargeable battery BA is detachably attached to the rear wheel side body 120.

[0019] The seat unit 40 has a seat surface 41 on which a passenger sits and a backrest 42. A center shaft 171 is rotatably attached to the front end of the front-wheel-side frame 111, and a handle shaft 181 is attached to the upper end of the center shaft 171 so as to be swingable in the front-rear direction. The handle shaft 181 can be fixed to an upper swing position shown in Figures 1 to 3, etc., by an angle adjustment mechanism described below, and can swing to a lower swing position shown in Figure 29. A handle 180 is fixed to the upper end of the handle shaft 181, and the handle includes a first operating unit 180a and a second operating unit 180b, each of which is an operating lever, a button, or the like. The passenger can move the operating units 180a, 180b toward the rear of the vehicle.

[0020] When the handle shaft 181 is not in a rotation position for a pivot turn, which will be described later, operating the operation unit 180a causes the control device 80, which will be described later, to rotate the pair of rear wheels 20 in the forward direction using both motors 50. Furthermore, when the handle shaft 181 is not in a rotation position for a pivot turn, operating the operation unit 180b causes the control device 80 to rotate the pair of rear wheels 20 in the backward direction using both motors 50. When the handle shaft 181 is in a rotation position for a pivot turn, operating the operation unit 180a or 180b causes the control device 80, which will be described later, to rotate the pair of rear wheels 20 in opposite directions using both motors 50. It is also possible for the control device 80 to drive the electric mobility 1 in an automatic driving mode based on a program, without the rider operating the handle 180, operation unit 180a, operation unit 180b, etc.

[0021] A signal corresponding to the amount of displacement of the operating portions 180a and 180b is transmitted to a control unit 60, which will be described later, and the motors 50 are driven in response to the signal.

[0022] As shown in FIG. 30, the control unit 60 includes a motor driver 70 that drives each motor 50, and a control device 80.

[0023] The control device 80 has a processor 81 having, for example, a CPU, RAM, etc., a storage device 82 having non-volatile memory, ROM, etc., and a transmitter / receiver 83. The storage device 82 stores a program for controlling the electric mobility 1, and the processor 81 operates based on the program and transmits drive signals for driving each motor 50 to the motor driver 70.

[0024] Each rear wheel 20 is attached to the rear-wheel-side vehicle body 120 via a rear-wheel suspension. As shown in FIG. 7 , each rear-wheel suspension has a swing base 131 and a spring 140 made of metal such as steel. The swing base 131 is formed using a material suitable for obtaining strength, such as aluminum or other metallic materials. A portion of the swing base 131 may be made of plastic. The electric mobility 1 of this embodiment has a swing unit 2 including the swing base 131 and a motor 50 fixed to the swing base 131. The swing unit 2 is a part that swings together with the swing base 131, and the swing unit 2 may further have other components.

[0025] The base end side of the swing base 131 is attached to the rear-wheel-side frame 121 of the rear-wheel-side body 120 so as to be swingable in the vertical direction, and when the swing base 131 swings, the tip of the swing base 131 moves in the vertical direction. The base end side of the swing base 131 is located toward the center in the width direction of the underside of the rear-wheel-side frame 121, and the tip end part of the swing base 131 is located outward in the width direction from the rear-wheel-side frame 121. In this embodiment, the base end, base end part, and base end side of the swing unit 2 are the base end, base end, and base end side of the swing base 131, and the tip end, tip end, and tip side of the swing unit 2 are the tip end, tip end, and tip side of the swing base 131.

[0026] More specifically, a pair of shaft support portions are provided on the underside of the rear wheel side frame 121, and each shaft support portion is provided with a through-hole extending in the front-rear direction. Meanwhile, as shown in Figure 4, a shaft 150 extending in the front-rear direction is fixed to the base end side of the swing base 131.

[0027] A bearing such as a plain bearing is provided between the shaft 150 and the shaft support portion.

[0028] With the above-described configuration, the oscillating base 131 oscillates around an oscillating axis 150a (see FIGS. 4, 7, etc.), which is the central axis of the shaft 150. Note that a shaft support portion may be provided on the base end side of the oscillating base 131, and the shaft 150 may be fixed to the underside of the rear wheel side frame 121.

[0029] As shown in Figures 6 and 7, a rear wheel support member 132 is provided at the tip of the oscillating base 131. The rear wheel support member 132 is a member provided at the tip of the oscillating base 131. In this embodiment, the oscillating base 131 and the rear wheel support member 132 are integrally formed by pressing (bending, cutting, etc.) a steel plate, welding, etc. When the rear wheel support member 132 is fixed to the oscillating base 131, the rear wheel support member 132 is part of the oscillating base 131. As shown in Figures 6 and 7, the rear wheel support member 132 extends upward from the tip of the oscillating base 131, and in this embodiment, the housing of the motor 50 is fixed to the rear wheel support member 132 with a plurality of bolts.

[0030] The hub 22 of the rear wheel 20 is fixed to the output shaft 51 of the motor 50. This supports the motor 50 and the rear wheel 20 at the tip of the oscillating base 131. In other words, the rear wheel support member 132 supports the rear wheel 20 to the oscillating base 131 via the motor 50. Other mechanical elements such as bearings, axles, other members, etc. may be fixed to the rear wheel support member 132, and the rear wheel support member 132 may support the rear wheel 20 via the other mechanical elements, axles, other members, etc. Also, the housing of the motor 50 may be fixed to the tip or middle portion of the oscillating base 131. In this case, the rear wheel 20 is supported by the oscillating base 131 via the motor 50 even without providing the rear wheel support member 132. Also, other mechanical elements such as bearings, axles, other members, etc. may be fixed to the tip of the oscillating base 131, and the tip of the oscillating base 131 may support the rear wheel 20 via the other mechanical elements, axles, other members, etc. In either case, the rear wheel 20 is disposed on the tip side of the swing base 131 and is supported by the swing base 131 so as to move up and down together with the tip side of the swing base 131 .

[0031] As shown in Figure 7, stopper portions 128a and 128b are provided on the underside of the rear-wheel-side frame 121, and when the tip end of the oscillating base 131 moves downward, the base end of the oscillating base 131 abuts against the rear-wheel-side frame 121 from below via the stopper portion 128a. This position is the lower limit swing position of the oscillating base 131. On the other hand, when the tip end of the oscillating base 131 moves upward, the base end of the oscillating base 131 abuts against the rear-wheel-side frame 121 from below via the stopper portion 128b. This position is the upper limit swing position of the oscillating base 131.

[0032] It should be noted that even if the tip of the oscillating base 131 oscillates downward, the base end of the oscillating base 131 may not come into contact with the rear wheel side frame 121 or the like, and the downward or upward oscillation of the oscillating base 131 may be stopped by the force of the spring 140. In this case, the position where the downward or upward oscillation of the oscillating base 131 is stopped by the support of the spring 140 becomes the lower limit oscillation position or the upper limit oscillation position.

[0033] The rear wheel width W1 (FIG. 7), which is the widthwise distance between the outer ends of one rear wheel 20 and the other rear wheel 20, is, for example, 450 to 650 mm. In this embodiment, the rear wheel width W1 is 530 to 550 mm. In contrast, the support shaft width W2 (FIG. 7), which is the widthwise distance between one swing axis 150a and the other swing axis 150a, is, for example, 50 to 200 mm. In this embodiment, the support shaft width W2 is 120 to 130 mm or less.

[0034] In this embodiment, the distance from the swing axis 150a to the outer edge of the rear wheel 20 is approximately 210 mm, and when the swing base 131 swings from the upper swing limit position to the lower swing limit position, the rear wheel 20 moves up and down by 25 mm or more. To improve passenger comfort, it is preferable that the rear wheel 20 be configured to move up and down relative to the body frame by 15 mm or more, and more preferably by 20 mm or more, but these numerical values ​​are not limiting and it is sufficient that the required suspension function is realized.

[0035] 6, one end of a spring 140 is attached to the tip of the oscillating base 131. In this embodiment, one end of the spring 140 is attached to the tip of the oscillating base 131 via a rear wheel support member 132. Note that one end of the spring 140 may be attached to another part of the oscillating base 131.

[0036] On the other hand, the other end of the spring 140 is attached to the rear wheel side frame 121 .

[0037] In this embodiment, the angle that the extension direction of the spring 140 forms with the width horizontal line is 20° or less. In one example, the width horizontal line is parallel to a line passing through the center point of the axle of one rear wheel 20 and the center point of the axle of the other rear wheel 20. In another example, the width horizontal line is parallel to a line passing through the radial center point of the axle of one front wheel 10 and the center point of the axle of the other front wheel 10.

[0038] In one example, the extension direction of the spring 140 is a straight line passing through the radial center of one end of the spring 140 and the radial center of the other end of the spring 140. For example, the angle is set in the range of 5° to 20°. If the angle is 50° or less, it may be possible to achieve the same function as when the angle is 20°.

[0039] It is also preferable to use a known non-linear spring as spring 140. One example of a non-linear spring has a different winding pitch at one end than at the other, which results in a higher spring rate as compression progresses than at the beginning of compression. Other types of non-linear springs may also be used.

[0040] In this manner, in this embodiment, the spring 140 extends in the vehicle width direction and also extends obliquely downward from the inside to the outside in the vehicle width direction.

[0041] When a force is applied to each rear wheel 20 from below and each rear wheel 20 moves upward relative to the rear-wheel-side frame 121, each spring 140 is compressed. Because the springs 140 are arranged as described above, the ratio of the horizontal force component to the vertical force component of the force applied from the other end of each spring 140 to the rear-wheel-side frame 121 is large. In other words, the vertical force is less likely to be transmitted from each spring 140 to the rear-wheel-side frame 121. It is also possible to provide a damper arranged in parallel with the spring 140. For example, a known damper such as an oil damper may be arranged inside the spring 140. In another example, instead of the spring (biasing member) 140, another biasing member such as an air cylinder may be provided. In this case, a biasing system can be configured that includes an air cylinder capable of supplying air to the base end and tip end of the cylinder, a pump that supplies air to the cylinder, electronically controlled valves provided on the base end and tip end of the cylinder, and a control device. By controlling the pump and the electronically controlled valve with the control device, it is possible to achieve an appropriate suspension function according to the weight of the rider. The biasing member may be any member that can apply a downward force to the swinging portion 2 when the tip side of the swinging portion 2 moves upward.

[0042] The electric mobility 1 is required to be small, lightweight, have a simple structure, and be durable, among other things. For this reason, the space available for arranging suspensions, springs, dampers, etc. is relatively small, and it is often not possible to make the suspensions, springs, dampers, etc. large. The above configuration is useful for effectively cushioning the force acting from below on the rear wheels 20 in a limited space. Note that the force from below includes the force that the rear wheels 20 receive from the ground when a rider sits on the seat unit 40, the force that the rear wheels 20 receive from unevenness in the ground when the electric mobility 1 is traveling, etc.

[0043] In this embodiment, the swing base 131 of the swing unit 2 extends outward in the vehicle width direction from the swing axis 150a and also extends substantially horizontally from the swing axis 150a. In this embodiment, when the angle formed by the extension direction of the swing base 131 or the swing unit 2 in the vehicle width direction with respect to the horizontal direction is 35° or less, it can be said that the swing base 131 extends substantially horizontally from the swing axis 150a. The angle is preferably 25° or less, more preferably 10° or less, and even more preferably 5° or less.

[0044] In one example, the extension direction of the oscillating base 131 (oscillating unit 2) is a direction passing through the centroid of the cross section of the base end of the oscillating base 131 and the centroid of the cross section of the tip end of the oscillating base 131. The cross section is a cross section cut by a plane extending in the longitudinal direction and the vertical direction of the vehicle. In another example, the extension direction of the oscillating base 131 is a direction in which the bottom surface or the top surface of the oscillating base 131 substantially extends.

[0045] In this embodiment, when no passenger is sitting on the seat unit 40, the rocking base 131 extends slightly downward from the rocking axis 150a relative to the horizontal. When a passenger sits on the seat unit 40, the rocking base 131 rocks upward against the reaction force of the spring 140, and the rocking base 131 extends slightly upward from the rocking axis 150a relative to the horizontal. When the passenger is light, the rocking base 131 extends horizontally from the rocking axis 150a or slightly downward from the horizontal.

[0046] In this state, one end of the spring 140 is attached to the tip of the swing base 131 via the rear wheel support member 132, and the spring 140 extends in the vehicle width direction as described above. Therefore, as the swing position of the swing base 131 approaches the upper limit swing position, the compression amount of the spring 140 per unit swing amount of the swing base 131 increases. With this configuration, when a lighter passenger is riding, the compression amount of the spring 140 per unit swing amount of the swing base 131 is smaller than when a heavier passenger is riding.

[0047] Alternatively, spring 140 may be a nonlinear spring whose spring rate increases as compression progresses. In one example, spring 140 is a nonlinear spring whose spring rate after increase is 1.3 times or more, preferably 1.5 times or more, of the spring rate before increase. In other words, the spring rate of the entire rear wheel suspension changes in accordance with the weight of the rider. Note that the mere fact that spring 140 is a nonlinear spring can achieve the effect of changing the spring rate of the entire rear wheel suspension in accordance with the weight of the rider.

[0048] In this way, the spring rate of the entire rear wheel suspension changes depending on the rider's weight, preventing excessive rocking of the rocking base 131 when a heavy rider is riding on the vehicle. This configuration, which adjusts the spring rate according to the rider's weight, not only reduces vibration but also protects each frame of the mobility body 30. Furthermore, when the electric mobility vehicle 1 turns or pivots, a large force is applied to the spring 140 of one of the pair of rear wheels 20. Here, the spring rate of the spring 140 increases when a large force is applied. For example, when a light rider is riding on the electric mobility vehicle 1 and the electric mobility vehicle 1 is stationary or moving straight, the spring rate has not yet increased, but when the electric mobility vehicle 1 turns or pivots, the spring rate of the outer rear wheel suspension increases. This suppresses the roll angle when turning or pivoting, stabilizing the posture of the electric mobility vehicle 1 and the rider.

[0049] Furthermore, in this embodiment, a swing control unit 3 is provided that prevents or restricts different vertical movements of the base ends of the pair of swing units 2, thereby preventing the tip side of one of the pair of swing units 2 from becoming higher than the tip side of the other, or restricts the height to within a predetermined range. As shown in Fig. 9 and other figures, the swing control unit 3 of this embodiment has a first member 310 and a second member 320 made of metal, hard plastic, or the like. More preferably, the first member 310 and the second member 320 are made of a spring material such as stainless steel or spring steel that is used in the manufacture of springs such as coil springs.

[0050] The first member 310 has a main body 310a fixed by bolts or the like to the base end portion of one (right side) of the pair of oscillating bases 131, and the second member 320 has a main body 320a fixed by bolts or the like to the base end portion of the other (left side) of the pair of oscillating bases 131. The first member 310 has a plurality of upper contact portions 311 arranged at intervals from each other in the vehicle longitudinal direction, and a plurality of lower contact portions 312 arranged at intervals from each other in the vehicle longitudinal direction.

[0051] In this embodiment, each of the contact portions 311, 312 extends inward in the vehicle width direction from the main body 310a and is fixed to the main body 310a. Alternatively, each of the contact portions 311, 312 is formed integrally with the main body 310a. As shown in Figures 8 and 9, the upper contact portions 311 and the lower contact portions 312 are arranged alternately in the vehicle front-rear direction. The upper contact portions 311 are arranged above the lower contact portions 312.

[0052] The second member 320 also has a plurality of upper contact portions 321 spaced apart from one another in the vehicle longitudinal direction, and a plurality of lower contact portions 322 spaced apart from one another in the vehicle longitudinal direction. Each of the contact portions 321, 322 extends from the main body 320a toward the inside of the vehicle in the vehicle width direction, and is fixed to the main body 320a. Alternatively, each of the contact portions 321, 322 is formed integrally with the main body 320a. As shown in Figures 8 and 9, the upper contact portions 321 and the lower contact portions 322 are alternately arranged in the vehicle longitudinal direction. The upper contact portions 321 are arranged above the lower contact portions 322.

[0053] The first member 310 and the second member 320 are fixed to a pair of swing bases 131 so that the upper contact portions 311 of the first member 310 and the lower contact portions 322 of the second member 320 are aligned in the vertical direction, and the lower contact portions 312 of the first member 310 and the upper contact portions 321 of the second member 320 are aligned in the vertical direction (FIG. 9). As described above, when the left and right rear wheels 20, which can move in the vertical direction, are positioned at the same height relative to the vehicle frame, that is, when the tip ends of the pair of swing bases 131 (swing units 2) are positioned at the same height relative to the vehicle frame, the first member 310 and the second member 320 do not come into contact with each other, or are in light contact with each other without engaging with each other in the vertical direction. The tip end of the swing base 131 (swing unit 2) is, for example, a specific portion at the tip of the swing base 131.

[0054] Here, the height position can be measured relative to a reference plane (reference height position) based on a reference element, a reference shape, a reference position, etc. of the rear-wheel-side body 120. The reference element is, for example, a part or all of the underside of the rear-wheel-side frame 121 in the body frame, a pair of anti-toppling members 126, their central axes, etc. The reference shape is, for example, a single or multiple characteristic shapes of the rear-wheel-side frame 121. The reference position is, for example, the height position of the specific part of the rear wheel 20 or the oscillating base 131 relative to the body frame, measured when the electric mobility 1 is stationary and unloaded.

[0055] For example, in the case of a reference element, a reference plane (reference height position) can be set based on a single or multiple grooves, protrusions, flat surfaces, etc. extending horizontally in the vehicle width direction on the underside of the rear wheel side frame 121, or holes, grooves, protrusions, flat surfaces, etc. lined up in the vehicle width direction on the underside of the rear wheel side frame 121. The reference shape and reference position can also be set in a similar manner.

[0056] When the electric mobility vehicle 1 is turning, centrifugal force acts on the electric mobility vehicle 1, and a large load may be applied to the rear wheel 20 on the outside of the turning or corner of the pair of rear wheels 20. In this case, the electric mobility vehicle 1 may lean toward the outside of the turning or corner, as indicated by the arrow in FIG. 3 . This behavior is sometimes referred to as rolling. This leaning behavior may also occur when a passenger puts their weight on one side of the vehicle width. For example, a passenger sitting on a stopped electric mobility vehicle 1 may put their weight on one side of the vehicle width to reach an item next to the electric mobility vehicle 1.

[0057] This leaning behavior can also occur when a passenger stands on the footrest and puts their weight on one side of the vehicle width. As mentioned above, this leaning behavior is more likely to occur when a soft rear wheel suspension is used to improve passenger comfort. This leaning behavior can also be considered a rotational behavior around an axis extending in the fore-and-aft direction of the vehicle.

[0058] In this embodiment, due to this tilting behavior, the height position of the tip end side of one of the pair of oscillating parts 2 becomes higher than the height position of the tip end side of the other oscillating part 2. For example, when the difference between the two height positions reaches a predetermined difference of 10 mm, the multiple upper contact portions 311 and the multiple lower contact portions 322 come into contact in the vertical direction. At this time, in this embodiment, the multiple lower contact portions 312 of the first member 310 and the multiple upper contact portions 321 of the second member 320 also come into contact in the vertical direction. This contact restricts the vertical movement of the first member 310 and the second member 320 relative to each other. In other words, the difference between the height position of the tip end side of one of the pair of oscillating parts 2 and the height position of the tip end side of the other oscillating part 2 is prevented or restricted from exceeding the predetermined difference. More specifically, the difference between the height position of the tip end side of one of the pair of oscillating parts 2 and the height position of the tip end side of the other oscillating part 2 is restricted to a predetermined range of 10 mm.

[0059] The predetermined range can be set as appropriate. Specific values ​​vary depending on factors such as the size of the electric mobility vehicle 1. For example, if the predetermined range is set to a relatively small range of 2 to 10 mm, the electric mobility vehicle 1 will be less likely to roll. If the predetermined range is set to a relatively large range exceeding 10 mm, the electric mobility vehicle 1 will have greater freedom of movement to tilt when turning.

[0060] This configuration reduces the tilting behavior while realizing a soft rear wheel suspension for improved rider comfort, as described above. This leads to improved driving performance of the electric mobility 1 and further improved rider comfort. Note that, if the first member 310 and the second member 320 are formed using spring material as described above, a configuration can be adopted in which, when the upper contact portion 311 and the lower contact portion 322 come into contact with each other in the vertical direction, the upper contact portion 311 and / or the lower contact portion 322 can deform within a range of elastic deformation in response to a force applied in the vertical direction to the contact portions. In this case, for example, a force of 500 N, 1000 N, or the like is applied to the contact portions in the vertical direction, and in response to this force, the tip of the upper contact portion 311 and / or the tip of the lower contact portion 322 can be displaced in the vertical direction by 0.3 mm or more, 0.5 mm or more, or 1 mm or more. This configuration is expected to soften the restriction on the displacement of the oscillating portion 2 and make the members 310 and 320 less susceptible to settling (permanent deformation).

[0061] Alternatively, the first member 310 may be provided with a single upper contact portion 311 and a single lower contact portion 312, and the second member 320 may be provided with a single upper contact portion 321 and a single lower contact portion 322. In this case as well, the above-described advantageous effects can be similarly achieved.

[0062] It is also possible to omit the second member 320 and achieve the above effect using only the first member 310. In this case, a portion of the base end of one oscillating base 131 is disposed below the plurality of upper contact portions 311 of the first member 310 fixed to the base end of the other oscillating base 131. Also, a portion of the base end of the other oscillating base 131 is disposed above the plurality of lower contact portions 312 of the first member 310. When the portion of the base end functions in the same manner as the second member 320, the above effect is achieved.

[0063] A part or all of the first member 310 and the second member 320 can be part of the base end of the oscillating base 131. For example, the upper contact portion 311 and the lower contact portion 312 may be integrally provided on the base end side of one oscillating base 131, and the upper contact portion 321 and the lower contact portion 322 may be integrally provided on the base end side of the other oscillating base 131.

[0064] Alternatively, a hole or a notch may be formed on the base end side of one of the oscillating bases 131, and a protrusion inserted into the hole or notch may be formed on the base end side of the other oscillating base 131. The upper end surface of the hole or notch functions as an upper contact portion that contacts the protrusion from above, and the lower end surface of the hole or notch functions as a lower contact portion that contacts the protrusion from below.

[0065] As mentioned above, in order to regulate the different direction swinging in which one of the base ends of a pair of swinging parts 2 swings in a different vertical direction relative to the other, it is sufficient that the base end side of at least one of the swinging parts 2 is provided with an upper contact portion that contacts the base end side of the other swinging part 2 from above and a lower contact portion that contacts it from below.

[0066] 10 and 11 can be used instead of the swing control unit 3 of this embodiment. The swing control unit 4 has a connecting member 400 in which a first fixing portion 410 is fixed to the base end side of one of the pair of swing bases 131 by a bolt or the like, and a second fixing portion 420 is fixed to the base end side of the other of the pair of swing bases 131 by a bolt or the like. The swing control unit 4 may have other members in addition to the connecting member 400.

[0067] The connecting member 400 has a force generating portion 430 made of metal, hard plastic, or the like that connects the first fixing portion 410 and the second fixing portion 420, and the force generating portion 430 has an elastically deformable shape. One end of the force generating portion 430 is a connecting portion with the first fixing portion 410, and the other end of the force generating portion 430 is a connecting portion with the second fixing portion 420.

[0068] An example of an elastically deformable shape is a shape disposed over a range of 170° or more around an axis 431 extending in the vehicle longitudinal direction, as shown in Figure 10. The axis 431 is disposed within an area surrounded by the force generating unit 430 and extends in the vehicle longitudinal direction. For this reason, the elastically deformable shape is usually a shape disposed over a range of 180° or more around the axis 431.

[0069] The cross-sectional shape of the force generating unit 430 may be various shapes, such as a shape consisting of a single arc, a shape formed by connecting multiple arcs, a shape formed by connecting one or multiple arcs with one or multiple straight lines, or a shape formed by removing some of the sides of a polygon. The cross-sectional shape is the shape of a cross section cut along a plane perpendicular to the longitudinal direction of the vehicle. Some or all of the arcs may have a center of curvature outside the force generating unit 430. The force generating unit 430 in FIG. 10 has a cross-sectional shape formed by connecting multiple arcs. Furthermore, the force generating unit 440 in FIG. 12, which is a modified example of a swing control unit 4', has a cross-sectional shape formed by connecting multiple arcs having a center of curvature outside the force generating unit 440.

[0070] Since the force generating units 430, 440 have the above-described configuration, when the base ends of the pair of oscillating bases 131 oscillate together upward or downward (same-direction oscillation), a first deformation occurs in which one end and the other end of the force generating units 430, 440 are displaced horizontally relative to each other. When the pair of oscillating bases 131 oscillate in the same direction, the force generating units 430, 440 having the above-described configuration apply a relatively small reaction force to the base ends of the pair of oscillating bases 131.

[0071] On the other hand, during different-direction swing, in which the base end of one of the pair of swing bases 131 swings upward or downward relative to the base end of the other, a second deformation occurs in which one end and the other end of the force generating units 430, 440 are displaced vertically relative to each other. In this manner, the force generating units 430, 440 deform in a different mode from that during same-direction swing. In this embodiment, the ratio of the force from the force generating units 430, 440 to the amount of deformation of the second deformation during different-direction swing (second spring constant) is 3 times or more, more preferably 5 times or more, compared to the ratio of the force from the force generating units 430, 440 to the amount of deformation of the first deformation during same-direction swing (first spring constant). This ratio may be 1.5 times or more. The ratio of the second spring constant to the first spring constant is not limited to this value, and may be any value that can reduce the tilting behavior as described above. The same applies to the following description.

[0072] Therefore, the swing control units 4, 4' suppress different-direction swinging, in which one of the base ends of the pair of swinging units 2 swings in a different vertical direction relative to the other. This configuration can suppress or restrict the difference in height between the tip end of one of the pair of swinging units 2 relative to the vehicle body frame and the tip end of the other of the pair of swinging units 2 from exceeding the predetermined range. In the case of suppression, the force generating units 430, 440 generate a sufficiently large force before the difference exceeds the predetermined range, thereby making it less likely that the difference will exceed the predetermined range. The same applies to the other force generating units.

[0073] It is also possible to use a swing control unit 4'' shown in FIG. 13, which has a modified shape of the force generating unit 430 of the swing control unit 4 described above in this embodiment. The force generating unit 430'' of the swing control unit 4'' also has an elastically deformable shape. The force generating unit 430'' is also shaped to be disposed over a range of 170° or more around an axis 431, and has a cross-sectional shape formed by connecting multiple arcs.

[0074] 14 can be used in place of the swing control unit 3 of this embodiment. The swing control unit 5 has a connecting member 500 in which a first fixing portion 510 is fixed to the base end side of one of the pair of swing bases 131 by a bolt or the like, and a second fixing portion 520 is fixed to the base end side of the other of the pair of swing bases 131 by a bolt or the like. The swing control unit 5 may have other members in addition to the connecting member 500.

[0075] The connecting member 500 has a force generating unit 530 made of a thread-like member, string-like member, band-like member, or the like that connects the first fixing portion 510 and the second fixing portion 520. The force generating unit 530 of this embodiment is made by winding a thread made of polyester fiber, nylon fiber, aramid fiber, or the like multiple times around the first fixing portion 510 and the second fixing portion 520. The thread-like member or string-like member can be made of chemical fiber such as polyester fiber, nylon fiber, or aramid fiber, natural fiber, or metal fiber. The band-like member can be made of metal, plastic, rubber, or the like. The force generating unit 530 of this embodiment may have a rubber-like elasticity that covers the force generating unit 530.

[0076] Since the connecting member 500 has the above-described configuration, during the same-direction swing, a first deformation occurs in the force generating unit 530, in which the first fixed portion 510 side and the second fixed portion 520 side of the force generating unit 530 are displaced horizontally relative to each other. The length of the force generating unit 530 between the first fixed portion 510 and the second fixed portion 520 is set so that a strong tension is not generated during the deformation.

[0077] On the other hand, during the different-direction swing, a second displacement occurs in the force generating unit 530, in which the first fixed portion 510 side and the second fixed portion 520 side of the force generating unit 530 are displaced vertically relative to each other. In this embodiment, the ratio (second spring constant) between the force (tension) from the force generating unit 530 and the deformation amount of the second deformation during the different-direction swing is 3 times or more, more preferably 5 times or more, compared to the ratio (first spring constant) between the force (tension) from the force generating unit 530 and the deformation amount of the first deformation during the same-direction swing. This ratio may be 1.5 times or more. As mentioned above, this ratio is not limited to these values. The deformation amount can also be considered as the displacement amount (change in distance) of the first fixed portion 510 relative to the second fixed portion 520.

[0078] Therefore, the swing control unit 5 suppresses or restricts opposite-directional swinging, in which one of the base ends of the pair of swinging units 2 swings in a different vertical direction relative to the other. This configuration suppresses or restricts the difference in height between the tip end of one of the pair of swinging units 2 relative to the body frame and the tip end of the other of the pair of swinging units 2 relative to the body frame from exceeding the predetermined difference.

[0079] The swing control unit 6 can also be provided on the swing base 131' in Figure 15. In Figure 15, components equivalent to those in the above embodiment are denoted by the same reference numerals. In Figure 15, the shaft 150 fixed to the base end of the right swing base 131' is positioned to the left of the shaft 150 fixed to the base end of the left swing base 131'. The swing control unit 6 has a connecting member 600 that connects the base end of the right swing base 131' to the base end of the left swing base 131'. The swing control unit 6 may have other members in addition to the connecting member 600.

[0080] The connecting member 600 can also be said to be a force generating unit made of a thread-like member, string-like member, band-like member, etc. that connects the base end side of the right oscillating base 131′ and the left oscillating base 131′. The force generating unit can be made of the same material as the force generating unit 530.

[0081] Since the connecting member 600 has the above-described configuration, the change in the distance between both ends of the force generating portion in the vertical direction (first deformation) is small during the same-direction swing. The length of the force generating portion is set so that a strong tension is not generated at this time.

[0082] On the other hand, during the opposite-direction swing, the distance between the two ends of the force generating unit in the vertical direction changes significantly (second deformation). In this embodiment, the ratio (second spring constant) between the force (tension) from the force generating unit during the same-direction swing and the deformation amount of the first deformation is three times or more, and more preferably five times or more, compared to the ratio (first spring constant) between the force (tension) from the force generating unit during the opposite-direction swing and the deformation amount of the second deformation. The ratio may be 1.5 times or more. As mentioned above, the ratio is not limited to these values. The deformation amount can also be considered as the displacement (change in distance) of the upper end of the force generating unit relative to the lower end.

[0083] Therefore, the swing control unit 6 suppresses or restricts opposite-directional swinging, in which one of the base ends of the pair of swinging units 2 swings in a different vertical direction relative to the other. This configuration suppresses or restricts the difference in height between the tip end of one of the pair of swinging units 2 relative to the body frame and the tip end of the other of the pair of swinging units 2 relative to the body frame from exceeding the predetermined difference.

[0084] The swing control unit 7 can also be provided on the swing base 131" in FIG. 16. In FIG. 16, the same components as those in the above embodiment are designated by the same reference numerals. In FIG. 16, the shaft 150 fixed to the base end of the right swing base 131" and the shaft 150 fixed to the base end of the left swing base 131" are spaced apart by a predetermined distance in the vehicle width direction. In FIG. 16, the rear wheel support member 132 is fixed to the swing base 131", but the lower end of the rear wheel support member 132 may be connected to the swing base 131" so as to be swingable in the vehicle width direction, as in a double wishbone suspension. In this case, the upper end of the rear wheel support member 132 is connected to an upper swing base (not shown) so as to be swingable in the vehicle width direction, as necessary.

[0085] The swing control unit 7 has a connecting member 700 in which a first fixing portion 710 is fixed to the base end side of one of the pair of swing bases 131'' by a bolt or the like, and a second fixing portion 720 is fixed to the base end side of the other of the pair of swing bases 131'' by a bolt or the like. The swing control unit 7 may have other members in addition to the connecting member 700. In one example, the fixing portions 710 and 720 are each pulleys fixed to the swing base 131'' coaxially with the swing axis 150a. The connecting member 700 also functions as a force generating unit.

[0086] The connecting member 700 has force generating portions 731, 732 made of thread-like, string-like, or band-like members that connect the first fixing portion 710 and the second fixing portion 720. The force generating portions 731, 732 of this embodiment are band-like members that can be created in the same way as the force generating portion 530. One end of the force generating portion 731 is fixed to the upper end of the fixing portion 710, and the other end of the force generating portion 731 is fixed to the lower end of the fixing portion 720. One end of the force generating portion 732 is fixed to the lower end of the fixing portion 710, and the other end of the force generating portion 732 is fixed to the upper end of the fixing portion 720.

[0087] Because connecting member 700 has the above-described configuration, during the same-direction swing, first fixed portion 710 and second fixed portion 720 rotate in different directions, and this rotation causes a first deformation in force generating portions 731 and 732. The lengths of force generating portions 731 and 732 between first fixed portion 710 and second fixed portion 720 are set so that strong tension is not generated during this deformation.

[0088] On the other hand, during the different direction swing, for example, the first fixed portion 710 and the second fixed portion 720 rotate in the same direction, and this rotation causes a second displacement in which one of the force generating portions 731, 732 is stretched more than the first deformation.

[0089] For this reason, during the second deformation, the swing control unit 7 suppresses or restricts rotation of the first fixed part 710 and the second fixed part 720 about the swing axis 150a with a force greater than during the first deformation. This suppresses or restricts different-directional swing, in which one of the base ends of the pair of swinging parts 2 swings in a different vertical direction relative to the other. This configuration suppresses or restricts the difference in height between the tip end side of one of the pair of swinging parts 2 relative to the body frame and the tip end side of the other of the pair of swinging parts 2 from becoming greater than the predetermined difference.

[0090] In the swing control unit 7, the first fixed portion 710 and the second fixed portion 720 may be gears such as spur gears instead of pulleys, and the first fixed portion 710 and the second fixed portion 720 may be meshed with each other. In this case, the meshed first fixed portion 710 and the second fixed portion 720 allow swing in the same direction and restrict swing in different directions. A single or multiple gears may be provided between the first fixed portion 710 and the second fixed portion 720. In this case, the rotation of the first fixed portion 710 may be transmitted to the second fixed portion 720 via a single or multiple gears, and the single or multiple gears may allow swing in the same direction and restrict swing in different directions. Furthermore, instead of a single or multiple gears, a member such as a rod or plate extending in the vertical direction may be provided, and rack gears extending in the vertical direction may be provided on both left and right ends of the member. In this case, if the member is attached to the vehicle body frame by a linear guide or the like so as to be movable only in the up and down direction, the member will allow swinging in the same direction and restrict swinging in the opposite directions.

[0091] As mentioned above, each of the swing control units controls the tilting behavior when the vehicle is moving, such as when the user stands on the footrest, and contributes to stabilizing the vehicle's posture, so they can also be called stabilizers.

[0092] When the swing control unit 4 is configured to connect a pair of swing units 2, like the connecting member 400 of the swing control unit 4, the spring constants of the force generating units 430, 430'', 440 when swinging in the same direction can be adjusted to supplement or replace the spring 140. In other words, the swing control unit has the function of a stabilizer as well as the function of a suspension spring.

[0093] The pair of front wheels 10 are steered by a steering mechanism. As shown in Figures 1, 4, etc., the steering mechanism of this embodiment has a center shaft 171, a base 172, a right knuckle 173 attached to the right side of the base 172 in the vehicle width direction, a left knuckle 174 attached to the left side of the base 172 in the vehicle width direction, and a pair of kingpins 175. The base 172 is composed of a single member or multiple members.

[0094] The center shaft 171 is attached to the front-wheel-side frame 111 so as to be rotatable about the first axis 101, and has a pitman arm 171a extending in a direction intersecting the first axis 101. In this embodiment, the pitman arm 171a extends in a direction substantially perpendicular to the first axis 101, but is not limited to this and can be set appropriately as long as at least one of the effects described below is achieved. In this embodiment, the base end of the pitman arm 171a is fixed to the center shaft 171 by a bolt, welding, or the like.

[0095] The right knuckle 173 and the left knuckle 174 are attached to the base 172 so as to be rotatable about the second axis 102, which is the central axis of the kingpin 175. The right knuckle 173 and the left knuckle 174 respectively have a right knuckle arm 173a and a left knuckle arm 174a extending in a direction intersecting the second axis 102. In this embodiment, the knuckle arms 173a, 174a extend in a direction substantially perpendicular to the second axis 102, but this is not limited to this and may be set as appropriate as long as at least one of the effects described below is achieved. In this embodiment, the base ends of the knuckle arms 173a, 174a are fixed to the knuckles 173, 174 by bolts, welding, etc.

[0096] The steering mechanism has a right rod 176 connecting the tip of the pitman arm 171a to the tip of the right knuckle arm 173a, and a left rod 177 connecting the tip of the pitman arm 171a to the tip of the left knuckle arm 174a.

[0097] With the above configuration, a link mechanism is formed that has at least four joints: a first connection portion between the center shaft 171 having the pitman arm 171a and the front wheel side frame 111; a second connection portion between the base 172 and the right knuckle 173; a third connection portion between the tip of the right knuckle arm 173a and one end of the right rod 176; and a fourth connection portion between the other end of the right rod 176 and the tip of the pitman arm 171a.

[0098] Furthermore, a link mechanism is configured having at least four joints: a fifth connecting portion between the center shaft 171 having the pitman arm 171a and the front wheel side frame 111, a sixth connecting portion between the base 172 and the left knuckle 174, a seventh connecting portion between the tip of the left knuckle arm 174a and one end of the left rod 177, and an eighth connecting portion between the other end of the left rod 177 and the tip of the pitman arm 171a. The fifth connecting portion is the same as the first connecting portion.

[0099] As shown in FIG. 17 , one end of each of the rods 176 and 177 is a joint part 176a or 177a, typically a universal joint such as a ball joint, and the rods 176 and 177 are connected to the knuckle arms 173a and 174a via the joint parts 176a and 177a. The other end of each of the rods 176 and 177 is a joint part 176b or 177b, typically a universal joint such as a ball joint, and the rods 176 and 177 are connected to the pitman arm 171a via the joint parts 176b and 177b. The length of the rod 176 is the distance between the center point of the spherical portion of the joint part 176a (the pivot center of the joint) and the center point of the spherical portion of the joint part 176b (the pivot center of the joint), and the same is true for the length of the rod 177. In this embodiment, the rods 176 and 177 are 165 to 175 mm long, but the present disclosure is not limited to this. In this embodiment, the third link is the center of the spherical portion of the coupling part 176a (the center of swing of the coupling), and the fourth link is the center of the spherical portion of the coupling part 176b (the center of swing of the coupling), as well as the seventh and eighth link.

[0100] 1, 17, etc., the joint parts 176b and 177b are stacked in the vertical direction. More specifically, the joint parts 176b and 177b are aligned in the direction of extension of the first axis 101. The other ends of the rods 176 and 177 may be stacked in the vertical direction, or may be aligned in the direction of extension of the first axis 101. This configuration is useful for increasing the pushing amount by changing the rod angle, as described below.

[0101] In this embodiment, as shown in FIG. 3 , the kingpin 175 is inclined in the longitudinal direction of the vehicle. In this embodiment, the inclination angle (caster angle) α1 of the second axis 102 of the kingpin 175 in the longitudinal direction of the vehicle is 2 to 4 degrees. To reduce the operating force of the handlebar 180 for elderly people and the like, the inclination angle α1 is preferably approximately 0 to 6 degrees, and more preferably 4 degrees or less. When straight-line stability is taken into consideration, the inclination angle α1 can be set in a range of 12 degrees or less. The inclination angle α1 can be set to an angle other than the above depending on the conditions and required performance. Note that, although the second axis 102 is inclined toward the rear of the vehicle in this embodiment, the present disclosure is not limited to this.

[0102] In this embodiment, as shown in FIGS. 1 and 17 , the kingpin 175 is inclined in the vehicle width direction. In this embodiment, the inclination angle α2 of the second axis 102 of the kingpin 175 with respect to the vehicle width direction is 9 to 10 degrees. Because of an increase in the pushing amount due to a change in the rod angle, which will be described later, the inclination angle α2 is 3 degrees or more, preferably 5 degrees or more, and more preferably 8 degrees or more. The inclination angle α2 may be set to an angle other than the above depending on the conditions and required performance. Note that, although the second axis 102 is inclined inward in the width direction in this embodiment, the present disclosure is not limited thereto. The inclination angle α2 is preferably 1 degree or more larger than the inclination angle α1, more preferably 3 degrees or more larger, and even more preferably 5 degrees or more larger.

[0103] As shown in FIG. 17 , the axle 11 of the right front wheel 10 is fixed to a right knuckle 173, and the axle 11 of the left front wheel 10 is fixed to a left knuckle 174. In this embodiment, when both front wheels 10 are steered for forward travel with a tilt angle α2, the camber angle is configured to be smaller than the tilt angle α2. In other words, if the camber angle of the front wheels 10 is set equal to the tilt angle α2, the front wheels 10 will have a negative camber angle equal to the tilt angle α2. However, in this embodiment, the front wheels 10 have a small positive or negative camber angle of a predetermined angle. The small predetermined angle is preferably 3° or less, and more preferably 2° or less. In this embodiment, the front wheels 10 have a positive camber angle of 1° or less or 0.5° or less. With this configuration, when both front wheels 10 are steered for forward travel, the axle 11 extends obliquely downward rather than perpendicular to the second axis 102.

[0104] It can be said that the second axis 102 extends mainly in the vertical direction in an inclined arrangement with the inclination angles α1 and α2. In addition, the second axis 102 extends slightly in the vehicle longitudinal direction and the vehicle width direction, and also extends mainly in the vertical direction. Therefore, it can be said that the second axis 102 extends at least in the vertical direction.

[0105] In this embodiment, as shown in Fig. 3, the center shaft 171 is inclined in the longitudinal direction of the vehicle. The inclination angle β of the first axis 101 of the center shaft 171 in the longitudinal direction of the vehicle is 5° or more, preferably 8° or more, and more preferably 10° or more. In this embodiment, the inclination angle β is set in the range of 8° to 12°, and in Fig. 3, the inclination angle β is 10° to 11°.

[0106] It can be said that the first axis 101 extends mainly in the vertical direction at an inclination angle β. Furthermore, since the inclination angle β extends slightly in the vehicle front-rear direction and mainly in the vertical direction, it can be said that the first axis 101 extends at least in the vertical direction. The inclination angle α1 is preferably smaller than the inclination angle β by 1° or more, more preferably by 3° or more, and even more preferably by 5° or more. Note that, although the first axis 101 is inclined toward the rear of the vehicle in this embodiment, the present disclosure is not limited thereto.

[0107] 18 , when the steering angle of both front wheels 10 is 0° or approximately 0°, or when both front wheels 10 are positioned at a steering angle for straight driving, the pitman arm 171a extends forward of the vehicle from the center shaft 171, and the knuckle arms 173a, 174a also extend forward of the vehicle from the knuckles 173, 174. At this time, in this embodiment, the third connecting portion is positioned outward in the vehicle width direction from the second connecting portion, and the seventh connecting portion is positioned outward in the vehicle width direction from the sixth connecting portion.

[0108] Furthermore, in this state, the height positions of the joint parts 176b, 177b (the fourth and eighth connecting parts) are higher than the height positions of the joint parts 176a, 177a (the third and seventh connecting parts). In other words, the rods 176, 177 are tilted so that the other end is higher than the other end. In this embodiment, the seventh connecting part is higher than the third connecting part by the difference in height between the eighth connecting part and the fourth connecting part so that the inclination of the right rod 176 is equal to the inclination of the left rod 177. Furthermore, due to this height difference, the length of the right rod 176 and the length of the left rod 177 differ by 1 mm or more. In this embodiment, the length of the right rod 176 and the length of the left rod 177 differ by 2 mm or more.

[0109] Each component is designed and set so that the above numerical values ​​are obtained when the electric mobility 1 is placed on a horizontal plane and in an unloaded state or when the predetermined load is applied.

[0110] 19 and 20 , when the rider turns the handlebars 180 and the handlebar shaft 181 so that the electric mobility 1 moves forward and left, the pitman arm 171a rotates to the left about the first axis 101. At this time, the height positions of the fourth and eighth links of the pitman arm 171a change in accordance with the leftward rotation and the tilt angle β. In this embodiment, because the first axis 101 is tilted toward the rear of the vehicle, the height positions of the fourth and eighth links move downward in accordance with the leftward rotation.

[0111] At this time, the left rod 177 pushes the tip end (seventh link) of the left knuckle arm 174a outward in the vehicle width direction, causing the left knuckle arm 174a to rotate to the left about the second axis 102. At this time, the height position of the seventh link of the left knuckle arm 174a changes in accordance with the left rotation and the tilt angle α2. In this embodiment, because the second axis 102 is tilted inward in the vehicle width direction, the left rotation and the tilt angle α2 act to move the height position of the seventh link upward.

[0112] For this reason, in this embodiment, the difference in height between the eighth link and the seventh link decreases in response to the leftward rotation, resulting in a decrease in the inclination of the left rod 177. Furthermore, in response to this decrease, the amount by which the left rod 177 pushes the tip end (seventh link) of the left knuckle arm 174a outward in the vehicle width direction increases.

[0113] In this embodiment, as the amount of leftward rotation of the pitman arm 171a increases, the downward movement of the height positions of the fourth and eighth links per unit angle of rotation increases. In this embodiment, as the amount of leftward rotation of the left knuckle arm 174a increases, the height position of the seventh link increases. Therefore, in this embodiment, it is possible to set the pushing amount to increase as the amount of leftward rotation increases.

[0114] During the leftward rotation, the tip end (third coupling portion) of the right knuckle arm 173a is pulled inward in the vehicle width direction by the right rod 176, causing the right knuckle arm 173a to rotate leftward about the second axis 102. At this time, the height position of the third coupling portion of the right knuckle arm 173a changes in accordance with the leftward rotation and the tilt angle α2. In this embodiment, because the second axis 102 is tilted inward in the vehicle width direction, the leftward rotation and the tilt angle α2 act to move the height position of the third coupling portion downward.

[0115] Therefore, in this embodiment, during the leftward rotation, the amount of decrease in inclination of the right rod 176 due to the decrease in the difference in height between the first and third connectors is smaller than or equal to the amount of decrease in inclination of the left rod 177 due to the decrease in the difference in height between the eighth and seventh connectors. Therefore, the increase in the amount by which the right rod 176 pulls the tip end (third connector) of the right knuckle arm 173a toward the inside in the vehicle width direction is smaller than or equal to the increase in the amount by which the left rod 177 pushes the tip end (seventh connector) of the left knuckle arm 174a toward the outside in the vehicle width direction. Note that, to differentiate the amount of decrease in inclination of the left and right rods 176, 177 as described above, it is also possible to position the kingpin 175 so that the upper side of the second axis 102 is positioned outward in the vehicle width direction relative to the lower side. In this case, the rods 176, 177 are tilted so that the other end is lower than the other end during a straight-ahead steering angle.

[0116] Depending on the degree of increase in the pushing amount and the pulling amount, the difference between the left and right steering angles when the pitman arm 171a is rotated to the left by a large amount can be made significantly larger than the difference in steering angle when the pitman arm 171a is rotated to the left by a small amount. The difference in steering angle is the difference between the inner wheel steering angle of the inner wheel (left front wheel 10) and the outer wheel steering angle of the outer wheel (right front wheel 10). When the pitman arm 171a is rotated to the right, as in the case of rotating to the left, the inner wheel steering angle of the inner wheel (right front wheel 10) is larger than the outer wheel steering angle of the outer wheel (left front wheel 10). Furthermore, the difference in steering angle when the pitman arm 171a is rotated to the right by a large amount can be made significantly larger than the difference in steering angle when the pitman arm 171a is rotated to the right by a small amount.

[0117] Using the above configuration, the following example of steering characteristics can be obtained, in which the steering angle difference when the pitman arm 171a is rotated to the right or left by a large amount is significantly larger than the steering angle difference when the pitman arm 171a is rotated to the right or left by a small amount. The example of steering characteristics includes the following: When the steering angle of the inner wheel (inner wheel steering angle) is approximately 20°, the steering angle of the outer wheel (outer wheel steering angle) is approximately 20°, resulting in a steering angle difference of 0° ( FIG. 19 ); When the steering angle of the inner wheel is approximately 45°, the steering angle of the outer wheel is approximately 42°, resulting in a steering angle difference of approximately 3° ( FIG. 20 ); When the steering angle of the inner wheel is approximately 102°, the steering angle of the outer wheel is approximately 78°, resulting in a steering angle difference of approximately 24° ( FIG. 21 ). In this example of steering characteristics, the steering angle difference is as described above both when the right front wheel 10 is the inner wheel and when the left front wheel 10 is the inner wheel.

[0118] In FIG. 21 , in a plan view, the intersection of the central axis A1 of the inner wheel (left front wheel 10) and the axis A3 passing through the center of the pair of rear wheels 20 and the intersection of the central axis A2 of the outer wheel (right front wheel 10) and the axis A3 are approximately aligned. "Approximately aligned" refers to a case where the distance between the two intersections is 4 cm or less. Furthermore, in the vehicle width direction, the two intersections are located between the two rear wheels 20. More specifically, in the vehicle width direction, the two intersections are located at intermediate positions between the two rear wheels 20. The intermediate position is preferably a completely central position, but also includes a position separated from the completely central position by 20 cm or less in the vehicle width direction, preferably by 15 cm or less, and more preferably by 10 cm or less. Furthermore, it is preferable that the two intersections are aligned or approximately aligned, but it is also acceptable for the two intersections to be located at intermediate positions. The distance between the two intersections is preferably 15 cm or less, more preferably 10 cm or less, and even more preferably 5 cm or less.

[0119] The above state is in accordance with the theory of Ackermann steering geometry and is useful for smoothly turning the electric mobility vehicle 1 around the intersection point. To achieve this turning, in the above state, the control device 80 drives the motor 50 so that the left and right rear wheels 20 rotate in opposite directions. This type of turning is referred to as a pivot turn in this embodiment. It is preferable that the rotation speeds of the left and right rear wheels 20 are the same, but this can be changed as appropriate depending on the conditions. For smooth turning, it is preferable that the two intersection points are located at or near the exact center position.

[0120] The above configuration is useful because the intersection location allows the steering angle difference when the pitman arm 171a rotates significantly to the right or left compared to the steering angle difference when the pitman arm 171a rotates slightly to the right or left. For example, as shown in FIG. 21 , when the steering angle of the inner wheel (left front wheel 10) approaches 90° or 100°, the pushing force of the left rod 177 makes it difficult to apply a rotational force to the left knuckle arm 174a. In this embodiment, a setting can be realized that increases the pushing force when the rotation to the right or left increases, which is useful for firmly applying a rotational force to the knuckle arms 173a, 174a of the inner wheel when the steering angle of the inner wheel approaches 90° or 100°.

[0121] As a comparative example, the results of a simple calculation of steering characteristics based on the theory of Ackermann geometry are shown. The simple calculation was performed using the formula tan α = 1 / ((1 / tan β) - (T / W)). α is the steering angle of the inner wheel, β is the steering angle of the outer wheel, T is the tread dimension, and W is the wheelbase dimension. In this simple calculation of steering characteristics, as an example, the wheelbase dimension is set to 2.2 times the tread dimension.

[0122] The steering characteristics of the comparative example include the following: when the steering angle of the inner wheel is approximately 20°, the steering angle of the outer wheel is approximately 17.5°, resulting in a steering angle difference of 2.5°; when the steering angle of the inner wheel is approximately 45°, the steering angle of the outer wheel is approximately 35°, resulting in a steering angle difference of approximately 10°; when the steering angle of the inner wheel is approximately 102°, the steering angle of the outer wheel is approximately 77°, resulting in a steering angle difference of approximately 25°.

[0123] The theory of Ackermann geometry is a theory that perfectly matches the positions of the two intersections. Therefore, when the steering angle of the inside wheel of the comparative example is approximately 102°, the positions of the two intersections perfectly match at the midpoint between the two rear wheels 20. In this way, the example of the steering characteristics of this embodiment described above is useful for smooth pivot turns, just like the comparative example.

[0124] Normally, the positions of the two intersections are aligned at the midpoint between the two rear wheels 20, so when the theory of Ackermann geometry is used, the steering angle difference gradually increases when the steering angle of the inner wheel is small, as described above. In contrast, in this embodiment, the increase in the steering angle difference after the steering angle of the inner wheel exceeds 45° is significantly greater than that according to the theory of Ackermann geometry, as described above. This configuration is useful for applying a strong rotational force from the rods 176, 177 to the knuckle arms 173a, 174a of the inner wheel when the steering angle of the inner wheel increases, as described above.

[0125] In this embodiment, the kingpin 175 is tilted inward in the vehicle width direction. The inner wheel is positioned further rearward of the kingpin 175 as the steering angle increases. At this time, the positive camber angle of the inner wheel increases. That is, the inner wheel tilts in a direction such that the lower side of the inner wheel moves under the axle 11. This movement causes the portion supported by the inner wheel to move downward due to gravity. For example, in FIG. 21 , the left front wheel 10 (inner wheel) tilts in a direction such that the lower side moves under the axle 11, and the left knuckle 174 moves downward due to gravity. Because gravity tends to move objects lower, this configuration can assist in setting the steering angle of the inner wheel to a deep angle, such as 90° or 100°, by using the pushing force of the rods 176 and 177.

[0126] Furthermore, in the example of the steering characteristics of this embodiment, the steering angle difference when the steering angle of the inner wheel is 20°, 45°, etc. does not conform to the theory of Ackermann geometry. It can also be said that when turning right or left at low speed, the front wheel 10 is in a state close to parallel steering geometry. In this embodiment, as the steering angle increases, the part supported by the inner wheel moves downward due to gravity. This configuration acts to increase the steering angle of the inner wheel. Because there is play due to gaps between the components of the steering mechanism and elastic deformation of each component, the above-mentioned gravity-related movement tends to increase the steering angle of the inner wheel within the range of play when turning right or left with a steering angle of the inner wheel of 45° or less. This contributes to smooth driving of the electric mobility 1 when turning right or left at low speed.

[0127] In the above example of the steering characteristic of this embodiment, when the steering angle of the inner wheel is a first angle that is any angle in the range of 40° to 45°, the steering angle difference is approximately 3° or less. Furthermore, when the steering angle of the inner wheel is 102° (second angle) that is any angle in the range of 90° or more, the steering angle difference is approximately 24°. At this time, the two intersection points are located between the two rear wheels 20. In this case, if the simplified calculation of the Ackermann geometry theory is performed on a narrow vehicle body where W is three times T, for example, the steering angle difference will be approximately 16° when the positions of the two intersection points coincide.

[0128] Therefore, the steering angle difference at the second angle can be said to be five times or more the steering angle difference at the first angle, and in the example of the steering characteristic, it is seven or eight times or more. This configuration means that when the steering angle of the inner wheel increases in a steering angle range close to 90° as described above, the increase in the steering angle difference per unit steering angle change of the inner wheel (when the steering angle of the inner wheel changes by 1°) becomes large. This configuration is useful for applying a strong rotational force from the rods 176, 177 to the knuckle arms 173a, 174a of the inner wheels when the steering angle of the inner wheels increases.

[0129] In this embodiment, the rods 176, 177 are tilted so that one end is higher than the other end when the pair of front wheels 10 are positioned at a straight steering angle. When the electric mobility 1 is viewed from the front as shown in FIG. 1 , the height difference between the third and fourth links and the seventh and eighth links is set to between 32 and 38 mm. The height difference at the straight steering angle is preferably 15 mm or greater, more preferably 20 mm or greater, and even more preferably 25 mm or greater. The height of each link can also be measured using the position of the center point of the spherical portion of the coupling parts 176a, 176b, 177a, and 177b (the center of oscillation of the coupling). Alternatively, the height can be measured using the position of a specific part of a fixing member, such as a bolt, that secures the coupling parts 176a, 176b, 177a, and 177b to the pitman arm 171a or the knuckle arms 173a and 174a.

[0130] In this embodiment, when the steering angle of the inner wheel is 102°, the height difference decreases by 9 to 10 mm in the rod 176 of the inner wheel, while the rod 177 of the outer wheel remains unchanged or increases by 5 mm or less. In other words, when the inner wheel changes from a straight-ahead steering angle to 102°, the difference in height between the third and fourth connecting portions of the rod 176 of the inner wheel decreases by 9 to 10 mm. This decrease is preferably 4 mm or more, more preferably 6 mm or more, and even more preferably 8 mm or more. Thus, when the steering angle of the inner wheel is the second angle, the difference in height between the right rod or the left rod corresponding to the inner wheel is clearly smaller, and the inclination angle of the rods 176, 177 of the inner wheel is correspondingly smaller. This configuration is extremely useful for applying a rotational force from the rods 176, 177 to the knuckle arms 173a, 174a of the inner wheel firmly when the steering angle of the inner wheel increases.

[0131] When the length of the rod 176 is 170 mm and the difference in height is 35 mm, the rod 176 is inclined at an angle (rod angle) of approximately 12° relative to the horizontal plane, and when the difference in height is 25 mm, the rod 176 is inclined at an angle (rod angle) of approximately 8.5° relative to the horizontal plane. At a straight-ahead steering angle, the rods 176, 177 are preferably inclined at an angle (rod angle) of 5° or more relative to the horizontal plane, more preferably 8° or more, and even more preferably 10° or more. To ensure that the rods 176, 177 apply a sufficient rotational force to the knuckle arms 173a, 174a, the angle at a straight-ahead steering angle is 40° or less, preferably 30° or less, and more preferably 20° or less.

[0132] In this embodiment, the right second axis 102 is inclined so that its upper side is positioned more inward in the vehicle width direction than its lower side. Furthermore, during a straight-ahead steering angle, the right knuckle arm 173a extends from the right knuckle 173 toward the front of the vehicle, and one end of the right rod 176 is connected to the tip of the right knuckle arm 173a. With this configuration, the height position of the one end of the right rod 176 changes as the steering angle of the right front wheel 10, which serves as the inner wheel, increases. This configuration achieves the above-described steering characteristics without using a complex structure, and is useful for applying a reliable rotational force from the rods 176 and 177 to the knuckle arms 173a and 174a of the inner wheel when the steering angle of the inner wheel increases.

[0133] In this embodiment, the first axis 101 is inclined so that its upper side is positioned rearward of the vehicle relative to its lower side. Furthermore, when the steering angle is straight ahead, the pitman arm 171a extends forward from the center shaft 171, and the other end of the right rod 176 is connected to the tip of the pitman arm 171a. With this configuration, the height position of the other end of the right rod 176 changes as the steering angle of the right front wheel 10, which serves as the inner wheel, increases. This configuration achieves the above-described steering characteristics without using a complex structure, and is useful for applying a reliable rotational force from the rods 176 and 177 to the knuckle arms 173a and 174a of the inner wheel when the steering angle of the inner wheel increases.

[0134] For example, as shown in Figure 21, when the steering angle of the inner wheel is 90° or more and the amount of rotation of the knuckle arms 173a, 174a of the inner wheel is also 90° or more, in order to apply a sufficient rotational force to the knuckle arms 173a, 174a of the inner wheel from the rods 176, 177, it is possible to consider a configuration in which the tip of the pitman arm 171a is positioned considerably forward of the knuckle arms 173a, 174a. However, this configuration would be an obstacle to reducing the longitudinal dimension of the electric mobility 1.

[0135] In this embodiment, the above configuration enables a reliable rotational force to be applied from the rods 176, 177 to the knuckle arms 173a, 174a of the inner wheels when the steering angle of the inner wheels increases. Therefore, this embodiment is also useful for reducing the longitudinal dimension of the electric mobility vehicle 1. In recent years, the number of cases in which the electric mobility vehicle 1 is used within facilities and luxury cruise ships has increased, making miniaturization of the electric mobility vehicle 1 particularly important. For example, if the electric mobility vehicle 1 cannot turn smoothly in an elevator, it will be necessary to reverse the electric mobility vehicle 1 when entering or exiting the elevator. This can result in situations in which it takes a long time for the electric mobility vehicle 1 to exit the elevator, which is undesirable for users of the electric mobility vehicle 1 and the elevator. For this reason, miniaturization and turning performance of the electric mobility vehicle 1 are important.

[0136] The front-wheel-side frame 111 has a longitudinal frame 111b manufactured by extrusion molding of a metal such as aluminum. As shown in FIG. 22 , the longitudinal frame 111b is elongated in the longitudinal direction of the vehicle and has one or more partition walls 111c that separate the interior space into upper and lower sections. Meanwhile, the vertical frame 111a is also manufactured by extrusion molding, and can use the same extrusion molding material as the longitudinal frame 111b. This configuration is useful for reducing manufacturing costs, weight, etc.

[0137] Furthermore, this embodiment employs the swing control unit that can reduce the leaning behavior. This configuration reduces the leaning behavior of the electric mobility 1 during a pivot turn or immediately before the start of a pivot turn. This is useful for making the movement of the rods 176, 177 as intended, or for making them as close to the intended movement as possible, and can also be said to be useful for allowing the electric mobility 1 to perform a smooth pivot turn.

[0138] One end of a curved member 112 made of a metal such as aluminum is fixed to the rear end of the longitudinal frame 111b by a fixing structure. As part of this fixing structure, one end of the curved member 112 is provided with one or more protrusions 113 extending toward the front of the vehicle. The protrusions 113 have an upper surface that fits along the lower surface of the partition wall 111c, and a plurality of through holes 113a are formed in the protrusions 113 at intervals in the longitudinal direction of the vehicle. Each of the through holes 113a passes through the protrusion in the up-down direction.

[0139] The vertical dimension of the protrusion 113 is equal to the distance between the bottom wall 111d of the longitudinal frame 111b and the partition wall 111c. For example, the protrusion 113 is inserted into the space between the partition wall 111c and the bottom wall 111d until one end of the curved member 112 comes into contact with the rear end of the longitudinal frame 111b.

[0140] The partition wall 111c has a plurality of holes formed at positions corresponding to the plurality of through holes 113a of the inserted protrusions 113. The bottom wall 111d also has a plurality of holes formed at positions corresponding to the plurality of through holes 113a of the inserted protrusions 113. The fixing structure also has a nut member 114 disposed on the partition wall 111c. The nut member 114 has female threads 114a formed at positions corresponding to the plurality of through holes 113a of the protrusions 113.

[0141] With the protrusion 113 inserted into the space and the nut member 114 placed on the partition wall 111c as described above, a plurality of bolts 115 are inserted into the plurality of holes in the partition wall 111c and screwed into the female threads 114a, thereby fixing one end of the curved member 112 to the rear end of the longitudinal frame 111b. The other end of the curved member 112 is fixed to the end of the vertical frame 111a by a similar fixing structure.

[0142] An angle adjustment mechanism is provided that adjusts the angle of the swing position of the handle shaft 181 in the front-to-rear direction around the axis 181a in Fig. 2. As shown in Figs. 24 and 25 , the angle adjustment mechanism has a first engagement member 183 fixed to the lower end of the handle shaft 181, and a second engagement member 184 fixed to the center shaft 171. When the first engagement member 183 rotates around the axis 181a relative to the second engagement member 184, the inclination of the handle shaft 181 in the front-to-rear direction changes.

[0143] A contact surface 183a of the first engaging member 183 with the second engaging member 184 is an uneven contact surface having, for example, a plurality of radially extending protrusions, and a contact surface 184a of the second engaging member 184 with the first engaging member 183 is a contact surface having a shape complementary to the contact surface 183a. A clamp lever 185 contacts the surface of the first engaging member 183 opposite to the contact surface 183a. The clamp lever 185 is attached to one end of a fastening shaft 186, and the clamp lever 185 is capable of swinging up and down around an axis 185a of its base end.

[0144] The clamp lever 185 has a first swing position where the tip end is positioned approximately directly above the base end, as shown in Figure 24, which is the clamping position, and a second swing position where it is rotated (swung) a predetermined angle from the clamping position, as shown in Figure 25, which is the release position. A known clamp lever having a cam curved surface formed on its base end can be used as the clamp lever 185. The clamping shaft 186 extends in a direction along the axis 181a, and in this embodiment, the central axis of the clamping shaft 186 coincides with the axis 181a. The clamping shaft 186 is movable in a direction along the central axis relative to the first engaging member 183 and the second engaging member 184.

[0145] A flanged bushing 186a, a nut 186b, etc. are fixed to the other end of the fastening shaft 186, and a plurality of disc springs are arranged on the outer circumferential surface of the other end of the fastening shaft 186 in a direction along the central axis of the fastening shaft 186. The plurality of disc springs constitute a spring member 187, although other spring members such as coil springs can also be used in place of the plurality of disc springs. The spring member 187 is sandwiched between the flanged bushing 186a and the center shaft 171. The flanged bushing 186a and the nut 186b are members that move together with the fastening shaft 186 when the fastening shaft 186 moves toward the clamp lever 185, thereby pushing the spring member 187 toward the center shaft 171.

[0146] When the clamp lever 185 is placed in the clamping position, the clamping shaft 186 moves toward the clamp lever 185, compressing the spring member 187 to a first compressed state. When the clamp lever 185 is placed in the release position, the clamping shaft 186 moves in the opposite direction to the clamp lever 185, and the spring member 187 reaches a second compressed state that is smaller in compression than the first compressed state. In the second compressed state, the spring member 187 is compressed to some extent. In another example, the spring member 187 is not compressed at all.

[0147] In this state, for contact surface 183a to move around axis 181a relative to contact surface 184a, a jumping-over operation is required in which spring member 187 moves in a direction along the central axis until the engagement of the protrusions and recesses with contact surface 184a is released. In this embodiment, the spring member 187 is configured to be compressed during this jumping-over operation. Therefore, as the inclination of the handle shaft 181 in the fore-and-aft direction changes, the spring member 187 is compressed each time the engagement of the protrusions and recesses between contact surface 183a and contact surface 184a is overcome. With this configuration, the user can gradually change the position of the handle shaft 181 in the fore-and-aft direction. Furthermore, the user can make this adjustment simply by setting clamp lever 185 to the release position.

[0148] After the handle shaft 181 is placed in the desired swing position, when the user swings the clamp lever 185 to the clamping position, the spring member 187 is compressed to a first compressed state. In this state, the remaining compression of the spring member 187 is smaller than the amount of movement required for the overcoming operation. This configuration is useful for preventing unintended changes in the swing position of the handle shaft 181, which is subject to large forces.

[0149] The portion of the first engaging member 183 that comes into contact with the base end of the clamp lever 185 has a first contact portion 183b made of a metal material and a second contact portion 183c made of a resin material. It is preferable to select a resin material with a low coefficient of friction. The first contact portion 183b and the second contact portion 183c are aligned in the direction of oscillation of the clamp lever 185. When the direction along the central axis is the up-down direction of the clamp, the second contact portion 183c is located directly below the axis 185a.

[0150] With this configuration, when the clamp lever 185 is in the clamping position, the base end of the clamp lever 185 contacts the first contact portion 183b and the second contact portion 183c. This ensures that the clamped state is maintained in the clamping position. On the other hand, when the clamp lever 185 moves from the clamping position to the release position, the base end of the clamp lever 185 contacts only the second contact portion 183c. This allows the clamp lever 185 to move smoothly from the clamping position to the release position.

[0151] The front-wheel-side vehicle body 110 is detachably connected to the rear-wheel-side vehicle body 120. As shown in FIG. 22 , in this embodiment, an upper engagement portion 191 and a lower engagement portion 192 located below the upper engagement portion 191 are provided at the rear end of the front-wheel-side frame 111 of the front-wheel-side vehicle body 110. The lower engagement portion 192 is an engagement portion that opens downward. As shown in FIGS. 27 and 28 , the rear-wheel-side frame 121 of the rear-wheel-side vehicle body 120 has an upper engaged portion 193 and a lower engaged portion 194 that are located at height positions corresponding to the upper engaging portion 191 and the lower engaging portion 192. In this embodiment, the engaged portions 193, 194 are frame components such as pipes or rods that extend in the vehicle width direction, for example.

[0152] The lower engaging portion 192, which is open downward, approaches the lower engaged portion 194 from diagonally forward, thereby engaging with the lower engaged portion 194 from above. Conversely, when disengaging the lower engaging portion 192 from the lower engaged portion 194, it is necessary to move the lower engaging portion 192 diagonally forward relative to the lower engaged portion 194.

[0153] As shown in Figure 22, a locking projection 192a that projects in the vehicle width direction is provided at the end of the lower engaging portion 192 in the vehicle width direction. Meanwhile, a locking rotating member 195 is attached to, for example, a part of the rear-wheel-side frame 121 of the rear-wheel-side body 120. In this embodiment, the rotating member 195 is rotatable about an axis 195c that extends in the vehicle width direction, but the rotating member 195 may also be rotatable about an axis that extends in another direction. In this embodiment, the rotating member 195 is rotatably attached to the pipe-shaped frame of the lower engaged portion 194.

[0154] The rotating member 195 has a battery contact portion 195a that protrudes radially from one portion of its circumference. The rotating member 195 also has a lock portion 195b that protrudes radially from another portion of its circumference. The rotating member 195 is urged to rotate in a predetermined direction (counterclockwise in FIG. 28 ) by a biasing member such as a torsion spring (not shown). As a result, in an unloaded state, the rotating member 195 is positioned as shown in FIG. 28 . In this position, the battery contact portion 195a is positioned so that it can contact the battery BA installed in the battery holder 196. Then, as shown in FIG. 27 , during the process of installing the battery BA in the battery holder 196, the battery BA presses the battery contact portion 195a in the direction opposite to the biasing direction of the biasing member. Once the battery BA is installed in the predetermined position, the rotating member 195 rotates to the position shown in FIG. 27 .

[0155] In this state, the locking portion 195b of the rotating member 195 is disposed at least forward of the locking projection 192a, and the locking portion 195b restricts at least forward movement of the locking projection 192a. This prevents the lower engaging portion 192 from moving diagonally forward relative to the lower engaged portion 194. In other words, the engagement between the lower engaging portion 192 and the lower engaged portion 194 cannot be released unless the battery BA is removed from the battery housing portion 196.

[0156] In this way, the rotating member 195 rotatably attached to the rear-wheel-side frame 121 rotates to a predetermined rotation position when the battery BA is attached. At the predetermined rotation position, the rotating member 195 comes into contact with a part of the front-wheel-side frame 111 that is engaged with the engaged portion of the rear-wheel-side frame 121, and this contact restricts movement of the lower engaging portion (engaging portion) 192 of the front-wheel-side frame 111 in a direction that disengages the engagement.

[0157] As shown in Figure 2 and other figures, a stand member 197 is attached to the rear end of the electric mobility 1. The stand member 197 is fixed to the seat unit 40 and has a support portion 197a extending rearward from the seat unit 40, and a widthwise extending portion 197b whose central portion is fixed to the support portion 197a and extends in the vehicle width direction. Both ends of the widthwise extending portion 197b are located further rearward than the central side of the vehicle, and anti-slip members 197c made of a material having rubber-like elasticity may be attached to both ends.

[0158] 29 , the user can tilt the electric mobility 1 backward using the anti-tip members 126 as a fulcrum, and place both ends of the widthwise extending portions 197b on the ground, allowing the electric mobility 1 to stand on its own thanks to the anti-tip members 126 and the widthwise extending portions 197b. This state is useful for reducing the storage space required for the electric mobility 1. Furthermore, the user can store the electric mobility 1 without having to perform any operations such as folding it.

[0159] The central axis of the spring 140 is disposed on the vehicle front side relative to the rotation axis of the rear wheel 20. This configuration is advantageous for reducing the dimension of the electric mobility 1 in the front-to-rear direction.

[0160] In addition, in the rear-wheel-side cover 120a, it is preferable that the fender 120b (FIG. 5) of the right rear wheel 20 is fixed to the right swinging unit 2. The same is true for the left fender 120b. For example, the fender 120b is fixed to the rear wheel support member 132 of the swinging unit 2, the motor 50, etc. using a plurality of bolts (not shown).

[0161] In this case, the fender 120b moves up and down together with the swinging part 2 and the rear wheel 20. Therefore, even if the rear wheel 20 moves significantly up and down around the swing axis 150a, the change in shape of the electric mobility device 1 appears small when viewed from the rear, side, etc. This configuration improves the functionality of the rear wheel suspension while maintaining the appearance of the electric mobility device 1, thereby improving the mood of the rider of the electric mobility device 1.

[0162] Note that even if two or more pairs of front wheels 10 are provided on the front-wheel-side vehicle body 110, the various effects of the rear wheel suspension, the stabilizer, and the steering mechanism can be similarly achieved. Furthermore, even if the electric mobility 1 is not provided with the rear wheel suspension, the stabilizer, etc., the various effects of the steering mechanism can be similarly achieved. Furthermore, even if another wheel is provided between the front wheels 10 and the rear wheels 20, or if another wheel is provided behind the rear wheels 20, the various effects of the rear wheel suspension and the stabilizer can be similarly achieved. Furthermore, even if the electric mobility 1 is not provided with the rear wheel suspension and the stabilizer, and is provided with a single or multiple rear wheels 20 instead of a pair of rear wheels 20, the various effects of the steering mechanism and similar effects can be achieved.

[0163] Furthermore, the above-described various effects of the rear wheel suspension, the stabilizer, and the steering mechanism can be achieved even if the front-wheel side body 110 and the rear-wheel side body 120 are permanently connected to each other. In this case, the front-wheel side frame 111 and the rear-wheel side frame 121 are, for example, integral with each other, and the front-wheel side frame 111 and the rear-wheel side frame 121 form the body frame of the electric mobility 1.

[0164] Furthermore, if the rear wheel support member 132 is not provided at the tip of the oscillating base 131, one end of the spring 140 may be fixed to another member such as the housing of the motor 50, or may be fixed to another member fixed to or provided on the oscillating base 131. In this case, one end of the spring 140 is attached to the tip of the oscillating base 131 via the member. On the other hand, one end of the spring 140 may be attached directly to the tip of the oscillating base 131. Even in these cases, the various effects of the rear wheel suspension described above can be achieved.

[0165] It is also possible to attach two (or more) seat units 40 aligned in the front-to-rear direction to the electric mobility 1. In this case, two (or more) people will be seated aligned in the front-to-rear direction on the electric mobility 1. Even in such a case, the various effects of the rear wheel suspension, the stabilizer, and the steering mechanism described above can be achieved.

[0166] REFERENCE SIGNS LIST 1 Electric mobility 2 Swing unit 3, 4, 4', 4'', 5, 6, 7 Swing control unit 10 Front wheel 20 Rear wheel 110 Front wheel side body 111 Front wheel side frame 120 Rear wheel side body 121 Rear wheel side frame 131 Swing base 132 Rear wheel support member 171 Center shaft 171a Pitman arm 172 Base 173 Right side knuckle 173a Right side knuckle arm 174 Left side knuckle 174a Left side knuckle arm 175 King pin 176 Right side rod 177 Left side rod 140 Spring BA Battery

Claims

1. A steering mechanism for steering a pair of front wheels of an electric mobility vehicle, configured to be able to steer the inner and outer wheels so that the steering angle difference between the inner wheel steering angle and the outer wheel steering angle when the inner wheel steering angle is at a first angle that is any angle in the range of 40° to 45° is five times or more when the inner wheel steering angle is at a second angle that is any angle in the range of 90° or more.

2. The pair of front wheels include a right front wheel and a left front wheel, the pair of front wheels including a center shaft that is rotatable at least about a first axis extending in a vertical direction and that rotates when a handle is operated, a pitman arm fixed to the center shaft, a right side knuckle that is rotatable at least about a second axis on the right side extending in a vertical direction and that supports the right front wheel, a right side knuckle arm provided on the right side knuckle, a left side knuckle that is rotatable at least about a second axis on the left side extending in a vertical direction and that supports the left front wheel, a left side knuckle arm provided on the left side knuckle, a right side rod having one end connected to the right knuckle arm and the other end connected to the pitman arm, and a left side rod having one end connected to the left knuckle arm and the other end connected to the pitman arm, 2. The steering mechanism according to claim 1, wherein when the pair of front wheels are positioned at a straight-ahead steering angle for straight-ahead driving of the electric mobility, each of the rods is positioned at an angle such that the difference in height position between the other end and the one end is 15 mm or more, and when the inner wheel steering angle is at the second angle, the difference in height position is 4 mm or more smaller than at the straight-ahead steering angle.

3. A steering mechanism for steering the right and left front wheels of an electric mobility vehicle, comprising: a center shaft that is rotatable at least about a first axis extending in a vertical direction and that rotates by operating a handlebar; a pitman arm fixed to the center shaft; a right knuckle that is rotatable at least about a second axis on the right side extending in a vertical direction and that supports the right front wheel; a right knuckle arm provided on the right knuckle; a left knuckle that is rotatable at least about a second axis on the left side extending in a vertical direction and that supports the left front wheel; a left knuckle arm provided on the left knuckle; a right rod having one end connected to the right knuckle arm and the other end connected to the pitman arm; and a left rod having one end connected to the left knuckle arm and the other end connected to the pitman arm, a steering mechanism in which, when the right front wheel and the left front wheel are positioned at a straight-ahead steering angle for driving the electric mobility in a straight line, each of the rods is positioned at an angle such that the difference in height position between the other end and the one end is 15 mm or more, and when the steering angle of the inner wheel is 90° or more, the difference in height position is 4 mm or more smaller than at the straight-ahead steering angle.

4. A steering mechanism as described in claim 2 or 3, wherein the right second axis is inclined in the vehicle width direction, the right knuckle arm extends from the right knuckle toward the front of the vehicle during the straight-ahead steering angle, and the one end of the right rod is connected to the tip of the right knuckle arm, so that the height position of the one end of the right rod changes as the steering angle of the right front wheel as the inner wheel increases.

5. A steering mechanism as described in claim 2 or 3, wherein the first axis is inclined toward the rear of the vehicle, the pitman arm extends from the center shaft toward the front of the vehicle when the steering angle is straight ahead, and the other end of the right side rod is connected to the tip of the pitman arm, so that the height position of the other end of the right side rod changes as the steering angle of the right front wheel as the inner wheel increases.

6. A steering mechanism according to claim 2 or 3, wherein the other end of the right rod and the other end of the left rod are arranged to be aligned vertically.

7. An electric mobility comprising: a pair of front wheels; a steering mechanism as defined in any one of claims 1 to 3; a pair of rear wheels; and a body frame; a pair of oscillating parts, wherein when one end of each of the oscillating parts in the vehicle width direction is a base end and the other end in the vehicle width direction is a tip end, the base end side of each of the oscillating parts is supported by the body frame so as to be able to oscillate in the vertical direction around a swing axis extending in the fore-and-aft direction of the vehicle, and each of the rear wheels is supported by the oscillating parts so as to move in the vertical direction together with the tip end side of each of the oscillating parts; a biasing member that applies a downward force to each of the oscillating parts when the tip end moves upward; and a swing control part that suppresses different directional swing in which one of the base end sides of the pair of oscillating parts swings in a different direction in the vertical direction relative to the other, or restricts it to a predetermined range.

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