Vehicle

Abstract

[Problem] To provide a vehicle with which it is possible to improve operability when traveling at high speed and to make the vehicle less liable to tip over when traveling at low speed. [Solution] A three-wheeled bike 1 comprises a saddle 2, wheels 3, a handlebar 4, a frame 5, and a differential leaning mechanism 6. The three-wheeled bike 1 comprises: a control device 8 for controlling the three-wheeled bike 1; and a differential leaning mechanism adjusting device 7 for adjusting a damping force of the differential leaning mechanism 6. The control device 8 comprises: a traveling speed detecting unit 81 for detecting the traveling speed of the three-wheeled bike 1; and a differential leaning mechanism control unit 82 for causing the differential leaning mechanism adjusting device 7 to adjust the damping force of the differential leaning mechanism 6 so as to reduce the damping force when the traveling speed detected by the traveling speed detecting unit 81 is high, and causing the differential leaning mechanism adjusting device 7 to adjust the damping force of the differential leaning mechanism 6 so as to increase the damping force when the traveling speed detected by the traveling speed detecting unit 81 is low.

Description

vehicle

[0001] The present invention relates to a vehicle having at least three wheels.

[0002] Conventionally, a vehicle has been known that includes a seat for a human body to sit on, at least three wheels, a handle for steering the wheels, and a frame that supports the wheels and the handle (see, for example, Patent Document 1). The vehicle described in Patent Document 1 has a pair of left and right rear wheels, and the pair of left and right rear wheels is equipped with a lean device (differential lean mechanism) that lowers one wheel as the other wheel rises and lowers one wheel as the other wheel rises. The lean device is configured to tilt the vehicle body in the left and right directions by driving a lean motor, so that the vehicle can turn stably by driving the lean device to tilt the vehicle body during turning.

[0003] JP 2014-69672 A

[0004] However, in a vehicle equipped with such a differential lean mechanism, if the damping force of the differential lean mechanism is set to a constant value, the vehicle will be able to travel more stably at high speeds compared to low speeds, but the vehicle's maneuverability will be reduced, and the vehicle may be more likely to tip over at low speeds compared to high speeds.

[0005] An object of the present invention is to provide a vehicle that can improve operability when traveling at high speeds and that is less likely to tip over when traveling at low speeds.

[0006] The vehicle of the present invention is a vehicle comprising a seating section for a human body to sit on, at least three wheels, a handlebar for steering the wheels, and a frame for supporting the wheels and the handlebar, wherein either the front wheels or the rear wheels have a pair of left and right wheels, and the pair of left and right wheels are equipped with a differential lean mechanism that lowers one wheel as the other wheel rises and lowers one wheel as the other wheel rises, and the vehicle is characterized by comprising a control device for controlling the vehicle and a differential lean mechanism adjustment device that adjusts the damping force of the differential lean mechanism, and the control device is equipped with a traveling speed detection unit that detects the vehicle's traveling speed, and a differential lean mechanism control unit that causes the differential lean mechanism adjustment device to adjust the damping force of the differential lean mechanism to reduce the damping force when the traveling speed detected by the traveling speed detection unit is high, and causes the differential lean mechanism adjustment device to adjust the damping force of the differential lean mechanism to increase the damping force when the traveling speed detected by the traveling speed detection unit is low.

[0007] With this configuration, the differential lean mechanism control unit controls the differential lean mechanism adjuster to reduce the damping force of the differential lean mechanism when the traveling speed detected by the traveling speed detector is high, and controls the differential lean mechanism adjuster to increase the damping force when the traveling speed detected by the traveling speed detector is low. This improves the vehicle's maneuverability when traveling at high speeds and makes it less likely to tip over when traveling at low speeds. Furthermore, by adjusting the damping force of the differential lean mechanism to an extremely large value, the vehicle can stand on its own when stopped without limiting the maximum lean angle to a certain value.

[0008] In the present invention, the differential lean mechanism comprises a predetermined cylindrical shaft, a differential lean link rotatably attached to the predetermined cylindrical shaft and having one end connected to one wheel via a swing arm and the other end connected to the other wheel via a swing arm, an annular first cam portion rotatably attached to the predetermined cylindrical shaft and rotating integrally with the differential lean link, an annular second cam portion non-rotatably attached to the predetermined cylindrical shaft and engaging with the first cam portion, and a moving mechanism that moves the position of the second cam portion along the predetermined cylindrical shaft, and the differential lean mechanism adjustment device comprises a biasing means that biases the second cam portion toward the first cam portion and an adjusting means that adjusts the biasing force of the biasing means, and it is preferable that the first cam portion and the second cam portion are engaged by fitting corresponding concave and convex surfaces together.

[0009] With this configuration, the first cam portion rotates integrally with the differential lean link, and the first cam portion and the second cam portion are engaged by fitting their corresponding concave and convex surfaces together, so that the second cam portion moves in a direction away from the first cam portion via the moving mechanism as the differential lean link rotates. The differential lean mechanism adjustment device includes a biasing means that biases the second cam portion toward the first cam portion, and an adjustment means that adjusts the biasing force of the biasing means. Therefore, the damping force of the differential lean mechanism can be adjusted to increase by increasing the biasing force of the biasing means, and can be adjusted to decrease the damping force by decreasing the biasing force of the biasing means.

[0010] In the present invention, the differential lean mechanism preferably includes a restricting means for restricting movement of the second cam portion in a direction away from the first cam portion.

[0011] According to this configuration, the differential lean mechanism includes a restricting means for restricting movement of the second cam portion away from the first cam portion, and by positioning the position where the restricting means restricts movement of the second cam portion close to the first cam portion, the clearance at the mating portion of the first cam portion and the second cam portion can be reduced, and by positioning the position where the restricting means restricts movement of the second cam portion away from the first cam portion, the clearance at the mating portion of the first cam portion and the second cam portion can be increased. Therefore, the differential lean mechanism can adjust the maximum lean inclination angle.

[0012] In the present invention, it is preferable that the restricting means is configured to be able to restrict the position at which the movement of the second cam portion is restricted to a position at which the second cam portion engages with the first cam portion.

[0013] According to this configuration, the regulating means is configured to be able to regulate the position at which the movement of the second cam portion is regulated to a position where it engages with the first cam portion, so that the clearance at the engaging portion of the first cam portion and the second cam portion can be set to zero, and the rotation of the differential lean link can be locked.

[0014] a perspective view of a three-wheeled motorcycle according to a first embodiment of the present invention; an enlarged perspective view of the left front wheel; an enlarged perspective view of a three-wheeled motorcycle with a reduced caster angle; an enlarged perspective view of a three-wheeled motorcycle with an increased caster angle; an enlarged perspective view of the differential lean mechanism as seen from the front wheel side; an enlarged perspective view showing the operation of the differential lean mechanism; a partial perspective view of the differential lean mechanism as seen from the right side; a view and cross-sectional view of the differential lean mechanism as seen from the front; an enlarged perspective view showing the operation of the differential lean mechanism when one wheel is lowered as the other wheel is raised; a partial perspective view of the differential lean mechanism as seen from the right side with the spring holder moved; a view and cross-sectional view of the differential lean mechanism as seen from the front with the spring holder moved Schematic diagram showing the overall configuration of a three-wheeled motorcycle. Partial perspective view of a differential lean mechanism according to a second embodiment of the present invention, as seen from the right side. Front view and cross-sectional view of the differential lean mechanism. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side. Partial perspective view of the differential lean mechanism according to the second embodiment, as seen from the right side.

[0015] [First Embodiment] A first embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a perspective view showing a three-wheeled motorcycle according to the first embodiment of the present invention. As shown in Fig. 1, the three-wheeled motorcycle 1 is a vehicle including a saddle 2 serving as a seat for a human body, three wheels 3, a handlebar 4 for steering the wheels 3, and a frame 5 supporting the wheels 3 and the handlebar 4. In Fig. 1, the vertically upward direction is defined as the +Z-axis direction, and two axes perpendicular to the Z-axis are defined as the X- and Y-axes. This also applies to the following drawings.

[0016] The wheels 3 include a front wheel 31 attached to the +Y axis direction side of the frame 5 and a rear wheel 32 attached to the -Y axis direction side of the frame 5. The front wheels 31 comprise a pair of left and right wheels, including a left front wheel 33 attached to the -X axis direction side of the frame 5 and a right front wheel 34 attached to the +X axis direction side of the frame 5. The rear wheel 32 is connected to a motor 35 attached to the frame 5. This motor 35 rotates the rear wheel 32, which is the drive wheel, about its axis of rotation in response to accelerator operation input by the rider of the three-wheeled bike 1.

[0017] In this embodiment, the wheels 3 include two front wheels 31, each having a pair of left and right wheels, but may also include two rear wheels, each having a pair of left and right wheels. Also, the wheels may include both two front wheels, each having a pair of left and right wheels, and two rear wheels, each having a pair of left and right wheels, and the vehicle may have at least three wheels.

[0018] 2 is an enlarged perspective view of the left front wheel. As shown in FIG. 2, the front wheel 31 includes a wheel 311, a hub 312 attached to the center of the wheel 311 and having a steering shaft (not shown) therein that extends radially, and a tire 313 attached along the outer periphery of the wheel 311. The steering shaft of the hub 312 is connected to a cylindrical caster variable shaft 314. Therefore, the caster angle, which is the angle of the steering shaft, of the front wheel 31 can be changed by rotating the caster variable shaft 314 about its axis.

[0019] As shown in Figures 1 and 2, the frame 5 is formed in a rectangular column shape and includes a swing arm 51 whose base end is supported so as to be freely rotatable around the X axis, and the caster adjustable shaft 314 is supported so as to be freely rotatable around the central axis by being inserted into a hole formed at the tip of the swing arm 51.

[0020] 1, the frame 5 is equipped with two setting plates 52 attached to both sides in the X-axis direction on the -Z-axis direction side of the saddle 2. Each setting plate 52 has multiple holes for attaching a steering link 53 that transmits operation input of the handlebars 4 by the rider of the three-wheeled bike 1, and a caster link rod 54 that rotates the caster variable shaft 314 around the X-axis.

[0021] The steering link 53 includes a steering rod 531 connected at one end to a steering arm 530 attached to the end of the handlebar 4 on the −Z axis direction side, a link member 532 connected at the +Z axis direction side to the other end of the steering rod 531 and rotatably attached to a hole formed in the setting plate 52, and a tie rod 533 connected at one end to the −Z axis direction side end of the link member 532. The other end of the tie rod 533 is connected to the front wheel 31 via a knuckle arm 534.

[0022] An operation input of the handlebars 4 by the rider of the three-wheeled bike 1 moves the tie rod 533 back and forth along the Y-axis direction via the steering arm 530, steering rod 531, and link member 532. By moving back and forth, the tie rod 533 transmits the operation input of the handlebars 4 to the front wheel 31 via the knuckle arm 534, and the front wheel 31 rotates around the steering axis.

[0023] In this way, the three-wheeled bike 1 is supported by the frame 5 and is equipped with a hub-center steering mechanism having a pair of left and right swing arms 51 that swing each front wheel 31 up and down, and a steering link 53 that connects the handlebars 4 and the hubs 312 of the front wheels 31 and steers each front wheel 31 based on operation of the handlebars 4.

[0024] The caster link rod 54 has its base end attached to a hole formed in the setting plate 52, and its tip end attached to one end of the reaction lever 55. The other end of the reaction lever 55 is connected to the end of the caster variable shaft 314 opposite the front wheel 31. Therefore, by moving the position of the hole in the setting plate 52 to which the base end of the caster link rod 54 is attached in the Y-axis direction, the caster angle can be changed by rotating the caster variable shaft 314 via the reaction lever 55.

[0025] FIG. 3 is an enlarged perspective view of the three-wheeled bike with the caster angle reduced. FIG. 4 is an enlarged perspective view of the three-wheeled bike with the caster angle increased. By moving the position of the hole in the setting plate 52 in the +Y-axis direction, the caster link rod 54 rotates the reaction lever 55 around the X-axis (see the clockwise arrow in the figure) as shown in FIG. 3, thereby reducing the caster angle. By moving the hole in the setting plate 52 in the -Y-axis direction, the caster link rod 54 rotates the reaction lever 55 around the X-axis (see the counterclockwise arrow in the figure) as shown in FIG. 4, thereby increasing the caster angle. Therefore, the setting plate 52, caster link rod 54, and reaction lever 55 function as a caster angle adjustment mechanism 50 (see FIG. 13), which adjusts the caster angle of the steering shaft of the steered wheels.

[0026] In addition, the pair of left and right front wheels 31 are equipped with a differential lean mechanism 6 that lowers one wheel (e.g., the right front wheel 34) as one wheel (e.g., the left front wheel 33) rises, and lowers one wheel as the other wheel rises.

[0027] 5 is an enlarged perspective view of the differential lean mechanism 6 as viewed from the front wheel side. As shown in FIG. 5, the differential lean mechanism 6 includes a pair of left and right shock absorbers 61 attached to the pair of left and right swing arms 51, a differential lean link 62 connecting the shock absorbers 61, and a rotation mechanism 63 that supports the differential lean link 62 rotatably relative to the frame 5 around the center of rotation of the differential lean link 62 in the X-axis direction.

[0028] 6 is an enlarged perspective view showing the operation of the differential lean mechanism. As shown in FIG. 6, the differential lean link 62 rotates about the Y axis (counterclockwise in the figure) as the left front wheel 33, which is one of the wheels, rises, thereby lowering the right front wheel 34, which is the other wheel. Furthermore, the differential lean link 62 rotates about the Y axis (clockwise in the figure) as the right front wheel 34, which is the other wheel, rises, thereby lowering the left front wheel 33, which is one of the wheels (not shown).

[0029] FIG. 7 is a partial perspective view of the differential lean mechanism as seen from the right side. FIG. 8A is a view of the differential lean mechanism as seen from the front side, and FIG. 8B is a cross-sectional view taken along line A-A in FIG. 8A. As shown in FIGS. 7 and 8 , the rotation mechanism 63 is inserted into a hole formed in a substantially L-shaped shaft holder 56 attached to the frame 5 and includes a cylindrical shaft 631 (a predetermined cylindrical shaft) fixed to the shaft holder 56 (see FIG. 8B). As shown in FIG. 8B, the differential lean link 62 has a circular hole formed in its center, and is rotatably supported by inserting the shaft 631 through a bearing 621. In other words, the differential lean link 62 is rotatable around the central axis of the shaft 631. The differential lean link 62 is rotatably attached to the shaft 631, and one end of the differential lean link 62 is connected to one wheel via the swing arm 51, and the other end is connected to the other wheel via the swing arm 51.

[0030] 7 and 8 , the rotating mechanism 63 includes an annular first cam 632 that is inserted through the shaft 631 and fixed to the differential lean link 62 so as to be coaxial with the shaft 631, and an annular second cam 633 that is inserted through the shaft 631 and engages with the first cam 632. The rotating mechanism 63 also includes a cylindrical slider 634 that is inserted through the shaft 631 and fixed to the second cam 633, a cylindrical spring holder 635 that is inserted through the shaft 631 and attached adjacent to the slider 634, a spring 636 that is inserted through the shaft 631 and sandwiched between the slider 634 and the spring holder 635 (see FIG. 8B ), and a disk-shaped stopper 637 that is attached to the end face of the shaft 631 on the +Y axis direction side.

[0031] 7, first cam 632 has a wavy end face on the +Y axis direction side (second cam 633 side). As described above, this first cam 632 is fixed to differential lean link 62 so as to be coaxial with shaft 631, and therefore rotates around the central axis of shaft 631 as differential lean link 62 rotates. Second cam 633 has a wavy end face on the −Y axis direction side (first cam 632 side) that corresponds to the wavy end face of first cam 632, and is configured to mate with first cam 632.

[0032] As shown in FIG. 8B , the slider 634 has an outer diameter slightly smaller than the inner diameters of the first cam 632 and the second cam 633, and is inserted into the first cam 632 and the second cam 633. The slider 634 has a sliding portion 6341 formed at the end on the −Y axis direction side and slidingly mating with a key groove formed on the outer circumferential surface of the shaft 631, and a flange portion 6342 formed at the end on the +Y axis direction side and fixed to the second cam 633. Therefore, the second cam 633 and the slider 634 are attached to the shaft 631 so that they slide integrally along the axial direction of the shaft 631 by moving the sliding portion 6341 along the key groove of the shaft 631. In other words, the slider 634 and the key groove of the shaft 631 function as a moving mechanism that moves the position of the second cam 633 along the shaft 631.

[0033] As described above, the differential lean mechanism 6 includes an annular first cam 632 (first cam portion) that is rotatably attached to the shaft 631 and rotates integrally with the differential lean link 62, an annular second cam 633 (second cam portion) that is non-rotatably attached to the shaft 631 and engages with the first cam 632, and a slider 634 (movement mechanism) that moves the position of the second cam 633 along the shaft 631. The first cam 632 and the second cam 633 are engaged with each other by fitting their corresponding wavy end faces (concave and concave surfaces) together.

[0034] In this embodiment, the first cam portion and the second cam portion are fitted together by fitting corresponding wavy end faces together, but they may be simply inclined surfaces, or may have any shape as long as they are fitted together by fitting corresponding uneven surfaces together.

[0035] The spring holder 635 has an inner diameter that is approximately the same as the inner diameter of the slider 634. The spring holder 635 is formed at the end on the +Y axis direction side, and has a threaded portion 6351 with an internal thread that screws into an external thread formed on the outer circumferential surface of the shaft 631 on the +Y axis direction side. Therefore, the spring holder 635 is attached to the shaft 631 so that when the spring holder 635 is rotated around the axis of the shaft 631, it moves along the axial direction of the shaft 631. Note that the stopper 637 has the function of preventing the spring holder 635 from falling off by restricting movement of the spring holder 635 in the +Y axis direction side.

[0036] Spring 636 is disposed between the outer periphery of shaft 631 and the inner periphery of slider 634 and spring holder 635. Spring 636 is sandwiched between sliding portion 6341 of slider 634 and threaded portion 6351 of spring holder 635. Therefore, spring 636 is compressed by the sliding of second cam 633 and slider 634 toward the +Y axis direction and the movement of spring holder 635 toward the −Y axis direction, and is extended by the sliding of second cam 633 and slider 634 toward the −Y axis direction and the movement of spring holder 635 toward the +Y axis direction.

[0037] 9 is an enlarged perspective view showing the operation of the differential lean mechanism when one wheel is lowered as the other wheel is raised. For example, as shown in FIG. 9, the differential lean link 62 rotates about the Y axis as the swing arm 51 (the swing arm 51 on the −X-axis side in the figure) of the left front wheel 33, which is one of the wheels, rises, thereby lowering the swing arm 51 (the swing arm 51 on the +X-axis side in the figure) of the right front wheel 34, which is the other wheel.

[0038] The first cam 632 rotates around the central axis of the shaft 631 as the differential lean link 62 rotates. Here, the first cam 632 and the second cam 633 have wavy end faces that engage with each other, so the second cam 633 and the slider 634 slide integrally toward the +Y axis direction along the axial direction of the shaft 631 as the first cam 632 rotates (see the arrow in the figure). The spring 636 is compressed by the sliding of the second cam 633 and the slider 634 toward the +Y axis direction. Therefore, the differential lean link 62 can rotate against the elastic force of the spring 636.

[0039] Fig. 10 is a partial perspective view of the differential lean mechanism as seen from the right side with the spring holder moved. Fig. 11(A) is a view of the differential lean mechanism as seen from the front with the spring holder moved, and Fig. 11(B) is a cross-sectional view taken along line A-A in Fig. 11(A). Spring holder 635 is attached to shaft 631 so that it can move along the axial direction of shaft 631 by rotating it around the axis of shaft 631, and therefore can be moved until it abuts against stopper 637, as shown in Figs. 10 and 11.

[0040] 12 is an enlarged perspective view showing the operation of the differential lean mechanism in a state in which one wheel is lowered as the other wheel is raised when the spring holder is moved until it abuts against the stopper. For example, as shown in FIG. 12, the differential lean link 62 rotates about the Y axis as the swing arm 51 (the swing arm 51 on the −X-axis side in the figure) of the left front wheel 33, which is one of the wheels, is raised, thereby lowering the swing arm 51 (the swing arm 51 on the +X-axis side in the figure) of the right front wheel 34, which is the other wheel.

[0041] The first cam 632 rotates around the central axis of the shaft 631 as the differential lean link 62 rotates. Here, the first cam 632 and the second cam 633 have wavy end faces that engage with each other, so the second cam 633 and the slider 634 slide integrally toward the +Y axis direction along the axial direction of the shaft 631 as the first cam 632 rotates. The spring 636 is compressed by the sliding of the second cam 633 and the slider 634 toward the +Y axis direction. Therefore, the differential lean link 62 can rotate against the elastic force of the spring 636.

[0042] Here, as described above, the spring 636 is extended by moving the spring holder 635 toward the +Y axis direction, and therefore the differential lean link 62 is able to rotate against the elastic force of the spring 636, which is smaller than when the spring holder 635 is moved toward the −Y axis direction. In other words, the damping force of the differential lean mechanism 6 can be reduced by moving the spring holder 635 toward the +Y axis direction, and the damping force of the differential lean mechanism 6 can be increased by moving the spring holder 635 toward the −Y axis direction, and so the spring holder 635 functions as part of the differential lean mechanism adjustment device 7 (see FIG. 13 ) that adjusts the damping force of the differential lean mechanism 6.

[0043] As described above, in this embodiment, the differential lean mechanism adjustment device 7 is provided with the spring 636 (biasing means) that biases the second cam 633 toward the first cam 632, and the spring holder 635 (adjusting means) that adjusts the biasing force of the spring 636. Note that in this embodiment, the differential lean mechanism adjustment device adjusts the damping force of the differential lean mechanism by including the biasing means and the adjusting means, but other structures may be adopted as long as they are capable of adjusting the damping force of the differential lean mechanism.

[0044] 13 is a schematic diagram showing the overall configuration of a three-wheeled bike. As shown in FIG. 13, the three-wheeled bike 1 includes a saddle 2, three wheels 3, a handlebar 4, a frame 5, a differential lean mechanism 6, a differential lean mechanism adjustment device 7, and a control device 8 that controls the three-wheeled bike 1.

[0045] The control device 8 includes a traveling speed detection unit 81 and a differential lean mechanism control unit 82. The traveling speed detection unit 81 detects the traveling speed of the three-wheeled bike 1, for example, by detecting the rotation speed of the motor 35. In this embodiment, the traveling speed detection unit 81 detects the traveling speed of the three-wheeled bike 1 by detecting the rotation speed of the motor 35, but the traveling speed of the three-wheeled bike 1 may also be detected by other methods, such as detecting the number of rotations of the motor 35.

[0046] The differential lean mechanism control unit 82 causes the differential lean mechanism adjustment device 7 to adjust the damping force of the differential lean mechanism 6 so as to reduce the damping force when the traveling speed detected by the traveling speed detection unit 81 is fast. Furthermore, the differential lean mechanism control unit 82 causes the differential lean mechanism adjustment device 7 to adjust the damping force of the differential lean mechanism 6 so as to increase the damping force when the traveling speed detected by the traveling speed detection unit 81 is slow. Specifically, the three-wheeled bike 1 is equipped with a drive unit (not shown) that rotates the spring holder 635, and the differential lean mechanism control unit 82 adjusts the damping force of the differential lean mechanism 6 by using this drive unit to rotate the spring holder 635 and move the spring holder 635 along the Y-axis direction.

[0047] This embodiment provides the following advantages and functions. (1) The differential lean mechanism control unit 82 controls the differential lean mechanism adjustment device 7 to adjust the damping force of the differential lean mechanism 6 to a smaller value when the traveling speed detected by the traveling speed detection unit 81 is high, and controls the differential lean mechanism adjustment device 7 to adjust the damping force of the differential lean mechanism 6 to a larger value when the traveling speed detected by the traveling speed detection unit 81 is low. This improves the operability of the three-wheeled motorcycle 1 when traveling at high speeds and makes it less likely to tip over when traveling at low speeds. Furthermore, by adjusting the damping force of the differential lean mechanism 6 to an extremely large value, the three-wheeled motorcycle 1 can stand on its own when stopped without limiting the maximum lean angle to a certain value.

[0048] (2) The differential lean mechanism adjustment device 7 is equipped with a spring 636 that biases the second cam 633 toward the first cam 632, and a spring holder 635 that adjusts the biasing force of the spring 636. Therefore, by increasing the biasing force of the spring 636, the damping force of the differential lean mechanism 6 can be adjusted to increase the damping force, and by decreasing the biasing force of the spring 636, the damping force of the differential lean mechanism 6 can be adjusted to decrease the damping force.

[0049] (3) Because the three-wheeled motorcycle 1 is equipped with a hub-center steering mechanism, it is possible to create a space between the handlebars 4 and the front wheel 31, compared to vehicles equipped with a front fork mechanism, which increases the design flexibility of the vehicle. For example, the three-wheeled motorcycle 1 can install a storage battery, a control device 8, etc. in this space. Furthermore, the three-wheeled motorcycle 1 can also be equipped with decorations in this space to improve its design.

[0050] Second Embodiment A second embodiment of the present invention will now be described with reference to the drawings. FIG. 14 is a partial perspective view of a differential lean mechanism according to the second embodiment of the present invention, as seen from the right side. FIG. 15(A) is a view of the differential lean mechanism as seen from the front, and FIG. 15(B) is a cross-sectional view taken along line A-A in FIG. 15(A). In the first embodiment, the differential lean mechanism 6 includes a pivot mechanism 63, which includes a spring 636. In contrast, in this embodiment, as shown in FIGS. 14 and 15, a differential lean mechanism 6A includes a pivot mechanism 63A, which does not include a spring. This embodiment differs from the first embodiment in that it includes a pivot mechanism 63A. In the following description, parts that have already been described are designated by the same reference numerals, and their description will be omitted.

[0051] 16 is an enlarged perspective view showing the operation of the differential lean mechanism when one wheel is lowered as the other wheel is raised. For example, as shown in FIG. 16, the differential lean link 62 rotates about the Y axis as the swing arm 51 (the swing arm 51 on the −X-axis side in the figure) of the left front wheel 33, which is one of the wheels, is raised, thereby lowering the swing arm 51 (the swing arm 51 on the +X-axis side in the figure) of the right front wheel 34, which is the other wheel.

[0052] The first cam 632 rotates around the central axis of the shaft 631 in conjunction with the rotation of the differential lean link 62. Here, the first cam 632 and the second cam 633 have wavy end faces that engage with each other. Therefore, the second cam 633 and the slider 634 slide integrally along the axial direction of the shaft 631 toward the +Y axis direction in conjunction with the rotation of the first cam 632 (see the arrow in the figure). The second cam 633 and the slider 634 are restricted from moving toward the +Y axis direction by abutting against the spring holder 635. Therefore, the spring holder 635 functions as a restricting means that restricts the movement of the second cam 633 in a direction away from the first cam 632. In this embodiment, the spring holder 635 does not clamp a spring. However, the spring holder 635 may clamp a spring, as in the first embodiment.

[0053] 17 is a partial perspective view of the differential lean mechanism from the right side with the spring holder moved. The spring holder 635 is attached to the shaft 631 so that it can move along the axial direction of the shaft 631 by rotating the spring holder 635 around the axis of the shaft 631. As shown in FIG. 17, the spring holder 635 can be moved in a direction approaching the first cam 632.

[0054] 18 is an enlarged perspective view showing the operation of the differential lean mechanism when one wheel is lowered as the other wheel is raised. For example, as shown in FIG. 18, the differential lean link 62 rotates about the Y axis as the swing arm 51 (the swing arm 51 on the −X-axis side in the figure) of the left front wheel 33, which is one of the wheels, is raised, thereby lowering the swing arm 51 (the swing arm 51 on the +X-axis side in the figure) of the right front wheel 34, which is the other wheel.

[0055] The first cam 632 rotates around the central axis of the shaft 631 in conjunction with the rotation of the differential lean link 62. Here, the first cam 632 and the second cam 633 have wavy end faces that engage with each other, so the second cam 633 and the slider 634 slide integrally toward the +Y axis direction along the axial direction of the shaft 631 in conjunction with the rotation of the first cam 632 (see the arrow in the figure). The second cam 633 and the slider 634 are restricted from moving toward the +Y axis direction by abutting against the spring holder 635. Here, in the example of FIG. 18 , the spring holder 635 is moved in a direction approaching the first cam 632, so the maximum lean inclination angle is smaller than in the example of FIG. 16 .

[0056] 19 is a partial perspective view of the differential lean mechanism as viewed from the right side with the spring holder moved. The spring holder 635 is attached to the shaft 631 so as to move along the axial direction of the shaft 631 by rotating the spring holder 635 about the axis of the shaft 631. As shown in FIG. 19 , the spring holder 635 can move the second cam 633 until it engages with the first cam 632. Therefore, in this embodiment, the spring holder 635 is configured to be able to restrict the position at which it restricts the movement of the second cam 633 to the position at which it engages with the first cam 632. Note that, although the spring holder 635 is configured to be able to restrict the position at which it restricts the movement of the second cam 633 to the position at which it engages with the first cam 632 in this embodiment, it is not necessary to be configured to be able to restrict the movement of the second cam 633 to the position at which it engages with the first cam 632.

[0057] According to this embodiment, in addition to the same effects and advantages as those of (3) in the first embodiment, the following effects and advantages can be achieved. (4) Since the differential lean mechanism 6A includes the spring holder 635 that restricts the movement of the second cam 633 in a direction away from the first cam 632, the clearance at the engagement portion between the first cam 632 and the second cam 633 can be reduced by bringing the position at which the spring holder 635 restricts the movement of the second cam 633 closer to the first cam 632, and the clearance at the engagement portion between the first cam 632 and the second cam 633 can be increased by moving the position at which the spring holder 635 restricts the movement of the second cam 633 away from the first cam 632. Therefore, the differential lean mechanism 6A can adjust the maximum lean inclination angle.

[0058] (5) The spring holder 635 is configured to be able to restrict the position that restricts the movement of the second cam 633 to a position where it engages with the first cam 632. Therefore, the clearance at the engagement portion of the first cam 632 and the second cam 633 can be set to zero, and the rotation of the differential lean link 62 can be locked.

[0059] Third Embodiment A third embodiment of the present invention will now be described with reference to the drawings. FIG. 20 is a schematic diagram showing the overall configuration of a three-wheeled motorcycle according to the third embodiment of the present invention. In the first embodiment, the caster angle adjustment mechanism 50 adjusted the caster angle of the steering shaft of the steered wheels by moving the position of the hole in the setting plate 52, to which the caster link rod 54 is attached, in the Y-axis direction. The control device 8 also included a traveling speed detection unit 81 and a differential lean mechanism control unit 82. In contrast, in this embodiment, as shown in FIG. 20 , the caster angle adjustment mechanism 50B includes a rod drive unit 57 that moves the caster link rod 54 along the Y-axis direction. The rod drive unit 57 moves the caster link rod 54 in the Y-axis direction to adjust the caster angle of the steering shaft of the steered wheels. This embodiment also differs from the first embodiment in that the control device 8B includes a traveling condition detection unit 83 and a caster angle adjustment mechanism control unit 84.

[0060] The riding state detection unit 83 detects the straight and turning riding states of the three-wheeled bike 1, for example, by detecting the rotation angle of the handlebars 4. In this embodiment, the riding state detection unit 83 detects the straight and turning riding states of the three-wheeled bike 1 by detecting the rotation angle of the handlebars 4, but the straight and turning riding states of the three-wheeled bike 1 may also be detected by other methods, such as detecting angular velocity with a gyro sensor.

[0061] When the riding condition detection unit 83 detects that the three-wheeled bike 1 is traveling straight, the caster angle adjustment mechanism control unit 84 causes the rod drive unit 57 to move the caster link rod 54 in the -Y axis direction, thereby adjusting the caster angle adjustment mechanism 50B to increase the caster angle; when the riding condition detection unit 83 detects that the three-wheeled bike 1 is turning, the caster angle adjustment mechanism control unit 84 causes the rod drive unit 57 to move the caster link rod 54 in the +Y axis direction, thereby adjusting the caster angle adjustment mechanism 50B to decrease the caster angle.

[0062] According to this embodiment, in addition to the same functions and effects as those of the first embodiment, the following functions and effects can be achieved: (6) When the riding condition detection unit 83 detects that the three-wheeled motorcycle 1 is traveling straight, the caster angle adjustment mechanism control unit 84 causes the caster angle adjustment mechanism 50B to adjust the caster angle of the steering wheel to increase the caster angle, and when the riding condition detection unit 83 detects that the three-wheeled motorcycle 1 is turning, the caster angle adjustment mechanism 50B to adjust the caster angle of the steering wheel to decrease the caster angle. This improves the stability of the three-wheeled motorcycle 1 when traveling straight and improves maneuverability when turning.

[0063] [Modifications of the Embodiments] The present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. For example, in the above-described embodiments, the spring holder 635 functions as a restricting means for restricting movement of the second cam 633 in a direction away from the first cam 632. However, the differential lean mechanism does not necessarily have to include a restricting means for restricting movement of the second cam portion in a direction away from the first cam portion. Also, in the above-described embodiments, the three-wheeled motorcycle 1 includes a hub-center steering mechanism that is supported by the frame 5 and includes a pair of left and right swing arms 51 that swing each front wheel 31 up and down, and a steering link 53 that connects the handlebars 4 to the hubs 312 of the front wheels 31 and steers each front wheel 31 based on operation of the handlebars 4. However, the three-wheeled motorcycle 1 does not necessarily have to include a hub-center steering mechanism.

[0064] As described above, the present invention can be suitably used in a vehicle having at least three wheels.

[0065] REFERENCE SIGNS LIST 1 Three-wheeled bike 2 Saddle (seating part) 3 Wheel 4 Handlebar 5 Frame 6, 6A Differential lean mechanism 7 Differential lean mechanism adjustment device 8, 8B Control device 31 Front wheel 32 Rear wheel 50, 50B Caster angle adjustment mechanism 51 Swing arm 52 Setting plate 53 Steering link 54 Caster link rod 55 Reaction lever 56 Shaft holder 57 Rod drive unit 61 Shock absorber 62 Differential lean link 63, 63A Rotating mechanism 81 Traveling speed detection unit 82 Differential lean mechanism control unit 83 Traveling state detection unit 84 Caster angle adjustment mechanism control unit 311 Wheel 312 Hub 313 Tire 314 Caster variable shaft 530 Steering arm 531 Steering rod 532 Link member 533 Tie rod 534 Knuckle arm 621 Bearing 631 Shaft (predetermined cylindrical shaft) 632 First cam (first cam portion) 633 Second cam (second cam portion) 634 Slider (movement mechanism) 635 Spring holder (adjustment means, restriction means) 636 Spring (biasing means) 637 Stopper 6341 Sliding portion 6342 Flange portion 6351 Threaded portion

Claims

1. A vehicle comprising a seating section for a human body to sit on, at least three wheels, a handlebar for steering the wheels, and a frame supporting the wheels and the handlebar, wherein either the front wheels or the rear wheels have a pair of left and right wheels, and the pair of left and right wheels are equipped with a differential lean mechanism that lowers one wheel as the other wheel rises and lowers one wheel as the other wheel rises, the vehicle comprising: a control device that controls the vehicle, and a differential lean mechanism adjustment device that adjusts the damping force of the differential lean mechanism, the control device comprising: a traveling speed detection unit that detects the traveling speed of the vehicle, and a differential lean mechanism control unit that causes the differential lean mechanism adjustment device to adjust the damping force of the differential lean mechanism to reduce the damping force when the traveling speed detected by the traveling speed detection unit is fast, and causes the differential lean mechanism adjustment device to adjust the damping force of the differential lean mechanism to increase the damping force when the traveling speed detected by the traveling speed detection unit is slow.

2. A vehicle as described in claim 1, wherein the differential lean mechanism comprises: a predetermined cylindrical axis; a differential lean link rotatably attached to the predetermined cylindrical axis, one end of which is connected to one wheel via a swing arm and the other end of which is connected to the other wheel via a swing arm; a first annular cam portion rotatably attached to the predetermined cylindrical axis and rotates integrally with the differential lean link; a second annular cam portion non-rotatably attached to the predetermined cylindrical axis and engages with the first cam portion; and a moving mechanism for moving the position of the second cam portion along the predetermined cylindrical axis; and the differential lean mechanism adjustment device comprises: a biasing means for biasing the second cam portion towards the first cam portion; and an adjustment means for adjusting the biasing force of the biasing means; and the first cam portion and the second cam portion are engaged by fitting corresponding concave and convex surfaces together.

3. A vehicle as described in claim 2, wherein the differential lean mechanism is provided with a restricting means for restricting movement of the second cam portion in a direction away from the first cam portion.

4. A vehicle as described in claim 3, characterized in that the restricting means is configured to be able to restrict the position at which the movement of the second cam portion is restricted to a position where it engages with the first cam portion.

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