Vehicle

Abstract

To provide a vehicle capable of improving driving stability during turning.SOLUTION: A tricycle 200 (vehicle) adjusts an arm length ratio a / b, which is a ratio of a length a of a lower arm 3 to a length b of a tie rod 6 as viewed from a traveling direction and an inter-arm angle θ, which is an angle between the lower arm 3 and the tie rod 6 as viewed from the traveling direction when the two front wheels 201 upright with the tilting mechanism not tilting the two front wheels 201, so that a difference in steering angles between two front wheels 201, generated when the tilting mechanism tilts the front wheels, is 10° or less.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle, and more particularly to a vehicle having two front wheels that are inclined in the vehicle width direction relative to the vertical direction. [Background technology]

[0002] BACKGROUND ART Conventionally, vehicles having two front wheels that are inclined in the vehicle width direction with respect to the vertical direction are known (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a tricycle (vehicle) with two front wheels that tilt widthwise relative to the vertical. In Patent Document 1, the tricycle (vehicle) is equipped with a structure (tilt mechanism) in which a handlebar post to which a handle is connected and a pair of side posts that support the two front wheels so that they can be turned are rotatably connected. The structure (tilt mechanism) tilts the pair of side posts left and right in response to the left and right tilt of the handlebar post, making it possible to oscillate (tilt) the two front wheels. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-19281 Summary of the Invention [Problem to be solved by the invention]

[0005] In a tricycle (vehicle) such as that described in Patent Document 1, the two front wheels can be tilted widthwise relative to the vertical direction. However, in a conventional tricycle (vehicle) such as that described in Patent Document 1, tilting the two front wheels widthwise relative to the vertical direction can result in a difference in steering angle between the two front wheels. The difference in steering angle between the two front wheels causes an operator to feel uncomfortable, reducing riding stability during cornering. For this reason, there is a demand for a vehicle that can improve riding stability during cornering by suppressing the operator's discomfort caused by the difference in steering angle between the two front wheels that occurs when the two front wheels are tilted widthwise relative to the vertical direction.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a vehicle that can improve driving stability when cornering. [Means for solving the problem]

[0007] To achieve the above object, the present inventors conducted extensive research and found that the operator can turn without feeling any discomfort when the difference in steering angle between the two front wheels caused by tilting the front wheels with a tilt mechanism is within 10°. Furthermore, the present inventors found through experiments and simulations that the difference in steering angle between the two front wheels caused by tilting the front wheels with a tilt mechanism is correlated with the arm length ratio a / b, which is the ratio of the length a of the lower arm section to the length b of the steering arm section as viewed from the direction of travel, and the inter-arm angle θ, which is the angle between the lower arm section and the steering arm section as viewed from the direction of travel when the front wheels are upright and not tilted by the tilt mechanism, and that by adjusting the arm length ratio a / b and the inter-arm angle θ, the difference in steering angle between the two front wheels caused by tilting the front wheels with a tilt mechanism can be kept within 10°.

[0008] That is, a vehicle according to one aspect of the present invention is a vehicle having two front wheels that rotate in the direction of travel, and is equipped with a tilt mechanism that tilts the front wheels in the vehicle width direction with respect to the vertical direction and includes a lower arm portion connected to two suspension portions that are connected to each of the two front wheels, and a steering mechanism that changes the steering angle of the front wheels in accordance with the steering of the vehicle and includes a steering arm portion connected to the two suspension portions so as to be positioned below the lower arm portion or at the same height as the lower arm portion when viewed from the direction of travel, and the arm length ratio a / b, which is the ratio of the length a of the lower arm portion to the length b of the steering arm portion when viewed from the direction of travel, and the arm angle θ, which is the angle between the lower arm portion and the steering arm portion when viewed from the direction of travel when the front wheels are upright and not tilted by the tilt mechanism, are adjusted so that the steering angle difference between each of the two front wheels caused by the tilt mechanism to be within 10°. Here, the term "vehicle" as used herein is a broad concept that includes bicycles with two front wheels, straddle-type vehicles such as motorcycles and tricycles, kick scooters, and recumbent bicycles.

[0009] In the vehicle according to this aspect, as described above, the arm length ratio a / b, which is the ratio of the length a of the lower arm section to the length b of the steering arm section as viewed from the direction of travel, and the inter-arm angle θ, which is the angle between the lower arm section and the steering arm section as viewed from the direction of travel when the front wheels are upright and not tilted by the tilt mechanism, are adjusted so that the difference in steering angle between the two front wheels, which is caused by tilting the two front wheels in the vehicle width direction with respect to the vertical, is within 10°. As a result, driving stability during cornering can be improved.

[0010] In the vehicle according to the above aspect, preferably, in a graph having inter-arm angle θ on the horizontal axis and arm length ratio a / b on the vertical axis, the inter-arm angle θ and the arm length ratio a / b are adjusted based on the range of arm length ratio a / b obtained by experiment or simulation in which the steering angle difference between each of the two front wheels caused by the tilt mechanism tilting the front wheels by 10° to 25° is within 10°, so that when |θ|, the absolute value of the inter-arm angle θ, is |θ|≦10°, the arm length ratio a / b is between a minimum line connecting the minimum values in the range of arm length ratios a / b and a maximum line connecting the maximum values in the range of arm length ratios a / b. Here, the inventors of the present application have calculated, through experiment and simulation, the range of arm length ratio a / b in which the steering angle difference between each of the two front wheels caused by the tilt mechanism tilting the front wheels by 25° is within 10° when |θ|, the absolute value of the inter-arm angle θ, is |θ|≦10°. By adjusting the inter-arm angle θ and the arm length ratio a / b so that they fall within the range of this calculated arm length ratio a / b, the inter-arm angle θ and the arm length ratio a / b can be easily adjusted.

[0011] In this case, preferably, the tilt mechanism and the steering mechanism are configured to have a structure in which one side and the other side in the vehicle width direction are line-symmetrical when viewed from the traveling direction, and in the graph above, on one side in the vehicle width direction, the inter-arm angle θ is -10°, which is positive when the lower arm portion and the steering arm portion widen outward in the vehicle width direction when viewed from the traveling direction, and negative when the lower arm portion and the steering arm portion approach each other outward in the vehicle width direction when viewed from the traveling direction. the inter-arm angle θ and the arm length ratio a / b are adjusted so that they fall within a range defined by a first region where the inter-arm angle θ is -10°≦θ≦2.5° and the arm length ratio a / b is 0.74≦a / b≦1.06, and a third region where the inter-arm angle θ is -5°≦θ≦0° and the arm length ratio a / b is 0.74≦a / b≦1.14. With this configuration, the adjustment ranges of the inter-arm angle θ and the arm length ratio a / b become clear, making it easier to adjust the inter-arm angle θ and the arm length ratio a / b. In addition, since the tilt mechanism and steering mechanism have a structure that is linearly symmetrical on one side of the vehicle width when viewed from the direction of travel, the movement of each of the two front wheels due to tilting and steering is approximately identical, thereby reducing the discomfort felt by the operator due to the different movement of each of the two front wheels due to tilting and steering.

[0012] In a vehicle in which the inter-arm angle θ and the arm length ratio a / b are adjusted to be within the range defined by the first, second, and third regions, the inter-arm angle θ and the arm length ratio a / b are preferably adjusted to be within the range defined by the second and third regions in the graph. Here, when the inter-arm angle θ is 2.5°<θ≦10°, the change in the steering angle of the front wheels caused by the tilt mechanism tilting the front wheels by 25° includes a relatively large change in the direction opposite to the direction in which the front wheels are tilted (the turning direction). Therefore, by adjusting the inter-arm angle θ and the arm length ratio a / b so that the inter-arm angle θ is within the range formed by the second and third regions, which are within the range of -10°≦θ≦2.5°, the change in the steering angle of the front wheels caused by the tilt mechanism tilting the front wheels 25° will no longer include a relatively large change in the direction opposite to the direction in which the front wheels are tilted (turning direction), thereby effectively suppressing the discomfort felt by the operator due to the difference in steering angle of each of the two front wheels caused by tilting the two front wheels in the vehicle width direction relative to the vertical direction.

[0013] In a vehicle in which the inter-arm angle θ and the arm length ratio a / b are adjusted to be within the range defined by the second and third regions, the inter-arm angle θ and the arm length ratio a / b are preferably adjusted to be within the range of the third region in the graph. Here, when the inter-arm angle θ is -10°≦θ<-5°, the change in the steering angle of the front wheels caused by the tilt mechanism tilting the front wheels by 25° is relatively large compared to when the inter-arm angle θ is -5°≦θ≦0°. Furthermore, when the inter-arm angle θ is 0°<θ≦2.5°, the change in the steering angle of the front wheels caused by the tilt mechanism tilting the front wheels by 25° includes a change in the direction opposite to the direction of tilting the front wheels (turning direction), unlike when the inter-arm angle θ is -5°≦θ≦0°. Therefore, by adjusting the inter-arm angle θ and the arm length ratio a / b so that the inter-arm angle θ is within the range of the region formed by the third region within the range of -5°≦θ≦0°, it is possible to prevent the change in the steering angle of the front wheels caused by the tilt mechanism tilting the front wheels by 25° from becoming too large and to prevent changes in the direction opposite to the direction in which the front wheels are tilted (turning direction), thereby effectively suppressing the discomfort felt by the operator due to the difference in steering angle of each of the two front wheels caused by tilting the two front wheels in the vehicle width direction relative to the vertical direction.

[0014] In the vehicle according to the above aspect, preferably, the tilt mechanism is constituted by a first link mechanism including two suspension parts, upper arms connected to the upper sides of each of the two suspension parts, lower arms connected to the lower sides of each of the two suspension parts, and a main body connecting the upper and lower arms and connected to the frame of the vehicle, and the steering mechanism is constituted by a second link mechanism including the two suspension parts, a steering arm, and a rotating part rotatable about a first axis perpendicular to the traveling direction and the vehicle width direction and connecting the main body and the steering arm. With this configuration, the tilt mechanism and the steering mechanism are constituted by a link mechanism, and therefore the tilt mechanism and the steering mechanism can be constituted with a relatively simple structure.

[0015] In this case, preferably, the two suspension units include a joint unit connected to the upper arm unit and the lower arm unit, and the joint unit is restricted from swinging in any direction other than the vehicle width direction. With this configuration, the link mechanism can restrict the tilt of the two front wheels in the vehicle width direction, thereby reducing the discomfort felt by the operator due to the two front wheels tilting in any direction other than the vehicle width direction.

[0016] In the vehicle according to the above aspect, the steering mechanism preferably includes a first pulley into which a string-like member is fitted, to which tension is applied in response to steering of the vehicle, and a portion of the first pulley with which the string-like member contacts has a non-circular shape when viewed from the direction of the rotation axis of the first pulley. This configuration enables the relationship between the steering angle and the steered angle of the front wheels, which changes in response to steering, to be adjusted nonlinearly, thereby optimizing the relationship between the steering angle and the steered angle of the front wheels, which changes in response to steering, depending on the steering situation of the operator. As a result, usability (user convenience) can be improved. Furthermore, because the above adjustment can be made simply by changing the shape of the first pulley, the design work can be simplified compared to when complex geometric design is required.

[0017] In this case, the steering system preferably further includes a second pulley that rotates in response to steering of the vehicle to apply tension to the string-like member, and the portion of the second pulley that contacts the string-like member has a non-circular shape when viewed from the direction of the rotation axis of the second pulley. With this configuration, in addition to the first pulley, the portion of the second pulley that contacts the string-like member has a non-circular shape. This allows for more non-linear adjustment of the relationship between the steering angle and the steered angle of the front wheels that changes in response to steering, compared to when only the portion of the first pulley that contacts the string-like member has a non-circular shape. This allows for a more optimal relationship between the steering angle and the steered angle of the front wheels that changes in response to steering, depending on the steering situation of the operator. As a result, usability (user convenience) can be further improved. Furthermore, because the above adjustments can be made simply by changing the shapes of the first and second pulleys, design work can be simplified compared to when complex geometric design is required.

[0018] The vehicle including the first pulley having a non-circular shape at the portion where the string-like member contacts preferably further includes a tension adjustment unit that presses the string-like member fitted onto the non-circular first pulley, and the tension adjustment unit is configured to apply tension to the string-like member by pressing the string-like member. Here, since the portion of the first pulley where the string-like member contacts has a non-circular shape, the tension applied to the string-like member decreases in response to steering, which may cause the operator to feel uncomfortable when turning. Furthermore, the decrease in tension applied to the string-like member may cause the string-like member to come off the first pulley. Therefore, applying tension to the string-like member by pressing the string-like member can prevent a decrease in the tension of the string-like member that would cause the operator to feel uncomfortable when turning, and can also prevent the string-like member from coming off the first pulley, which would cause the vehicle to become unable to travel. As a result, traveling stability during turns can be effectively improved. [Effects of the Invention]

[0019] As described above, the vehicle of the present invention can improve driving stability during cornering. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing the overall configuration of a tricycle according to one embodiment. [Figure 2] FIG. 1 is a front view of a suspension system for a tricycle according to one embodiment. [Figure 3] FIG. 1 is a rear view of a suspension system for a tricycle according to an embodiment. [Figure 4] FIG. 1 is a front view of a suspension system for a tricycle according to one embodiment, with the two front wheels not tilted in the vehicle width direction relative to the vertical direction. [Figure 5] FIG. 1 is a top view of a suspension system for a tricycle according to one embodiment, in a state in which the two front wheels are not tilted in the vehicle width direction relative to the vertical direction. [Figure 6]FIG. 1 is a front view showing a state of a suspension device for a tricycle in one embodiment in which the two front wheels are tilted in the vehicle width direction relative to the vertical direction. [Figure 7] FIG. 10 is a top view illustrating the steering angle difference of the suspension system of a tricycle in one embodiment when the two front wheels are tilted in the vehicle width direction relative to the vertical direction. [Figure 8] 7 is a cross-sectional view of the joint portion taken along line VII-VII in FIG. 4. [Figure 9] 8 is a cross-sectional view of the joint portion taken along line VIII-VIII in FIG. 4. [Figure 10] 10A and 10B are diagrams illustrating an arm length ratio a / b and an inter-arm angle θ according to one embodiment. [Figure 11] 10 is a graph illustrating the relationship between the arm length ratio a / b and the steering angle difference when the front wheels are tilted at an angle of 25° when the inter-arm angle θ=0° according to one embodiment. [Figure 12] 10 is a graph illustrating an area representing an adjustment range of an inter-arm angle θ and an arm length ratio a / b according to one embodiment. [Figure 13] 10 is a graph illustrating a region showing a more preferable adjustment range of the inter-arm angle θ and the arm length ratio a / b according to one embodiment. [Figure 14] 10 is a graph illustrating the difference in the adjustment range of the inter-arm angle θ and the arm length ratio a / b depending on the tilt angle according to one embodiment. [Figure 15] FIG. 1 is a side view of a tricycle according to one embodiment. [Figure 16] FIG. 2 is a bottom view showing a front wheel side pulley, a handle side pulley, and a tension adjustment unit according to one embodiment. [Figure 17] 4 is a graph illustrating the relationship between the rotation angles of a handle-side pulley and a front-wheel-side pulley according to one embodiment. [Figure 18] FIG. 10 is a bottom view showing a front wheel side pulley, a handle side pulley, and a tension adjuster according to Modification 1 of the embodiment. [Figure 19] 10 is a graph illustrating the relationship between the rotation angles of a handle-side pulley and a front-wheel-side pulley according to Modification 1 of the embodiment. [Figure 20]FIG. 10 is a diagram showing the shape of a pulley according to a second modified example of the embodiment. [Figure 21] FIG. 10 is a diagram showing a tension adjusting section according to a third modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] (Tricycle configuration) The configuration of a tricycle 200 according to one embodiment of the present invention will be described with reference to Figures 1 and 15. In the following description, the direction along the width of the tricycle 200 is referred to as the X direction, the direction along the direction of travel of the tricycle 200 is referred to as the Y direction, and the direction perpendicular to the X and Y directions and along the height of the tricycle 200 is referred to as the Z direction. One side of the X direction will be referred to as the X2 direction, and the other side will be referred to as the X1 direction. In the Y direction, the direction in which the tricycle 200 moves forward will be referred to as the Y2 direction, and the direction in which the tricycle 200 moves backward will be referred to as the Y1 direction. In the Z direction, the direction in which the height increases will be referred to as the Z1 direction, and the direction in which the height decreases will be referred to as the Z2 direction. The tricycle 200 is an example of a "vehicle" as defined in the claims.

[0023] As shown in Figures 1 and 15, tricycle 200 includes two front wheels 201, handlebars 202, a frame 203, a saddle 204, a rear wheel 205, a suspension system 100, a handlebar-side pulley 9, a tension adjustment unit 13, and a wire 8. Tricycle 200 is configured so that it can travel in the forward direction (Y2 direction) on the surface on which the two front wheels 201 and rear wheels 205 are placed by rotating in the forward direction (Y2 direction) of the two front wheels 201 and rear wheels 205. Tricycle 200 is a straddle-type vehicle configured so that an operator (not shown) can straddle saddle 204 while holding handlebars 202.

[0024] (Suspension system configuration) Next, the configuration of the suspension system 100 according to one embodiment of the present invention will be described with reference to FIGS.

[0025] As shown in Figures 2 to 4, the suspension device 100 includes a knuckle arm 1, an upper arm 2, a lower arm 3, a suspension bracket 4, a damper 5, a tie rod 6, and a pivoting unit 7. The upper arm 2 and the lower arm 3 are provided to extend in the width direction (X direction) of the tricycle 200. Furthermore, the knuckle arm 1, the upper arm 2, the lower arm 3, the suspension bracket 4, the damper 5, the tie rod 6, and the pivoting unit 7 are line-symmetrical with respect to a center line C2 (see Figure 4) that divides the tricycle 200 into one side and the other side in the vehicle width direction when viewed from the direction of travel of the tricycle 200 (Y2 direction). Furthermore, the knuckle arm 1, the upper arm 2, the lower arm 3, and the tie rod 6 are provided in pairs so that they each have a symmetrical structure on one side (X2 side) and the other side (X1 side) in the vehicle width direction of the tricycle 200. Therefore, in the following description of the suspension device 100, unless otherwise specified, the description will be focused on one side (X2 side) of the tricycle 200 in the vehicle width direction. The knuckle arm 1 is an example of a "suspension portion" in the claims. The upper arm 2 is an example of an "upper arm portion" in the claims. The lower arm 3 is an example of a "lower arm portion" in the claims. The suspension bracket 4 is an example of a "main body portion" in the claims. The tie rod 6 is an example of a "steering arm portion" in the claims.

[0026] As shown in FIG. 4, the knuckle arm 1 includes a ball joint shaft 11 and a ball joint shaft 12. The upper arm 2 includes a ball joint bearing 21. The lower arm 3 includes a ball joint bearing 31. The ball joint shaft 11 is composed of a shaft portion 11a and a spherical portion 11b. The shaft portion 11a is fixed to the end of the knuckle arm 1 on the upper side (Z1 side), and the spherical portion 11b is connected to be fitted inside the ball joint bearing 21. The ball joint shaft 12 is composed of a shaft portion 12a and a spherical portion 12b. The shaft portion 12a is fixed to the end of the knuckle arm 1 on the lower side (Z2 side), and the spherical portion 12b is connected to be fitted inside the ball joint bearing 31. The ball joint shaft 11 and the ball joint shaft 12 are examples of a "joint" in the claims.

[0027] As shown in Figure 8, ball joint bearing 21 has an opening 22 through which shaft 11a passes. Opening 22 extends in the width direction (X direction) of tricycle 200 and is provided to restrict swinging of ball joint shaft 11 in directions other than the width direction (X direction) of tricycle 200. In other words, ball joint shaft 11 is configured to swing only in the width direction (X direction) of tricycle 200 along opening 22.

[0028] As shown in Figure 9, the ball joint bearing 31 has an opening 32 through which the shaft 12a passes. The opening 32 extends in the width direction (X direction) of the tricycle 200 and is provided to restrict the ball joint shaft 12 from swinging in any direction other than the width direction (X direction) of the tricycle 200. In other words, the ball joint shaft 12 is configured to swing only in the width direction (X direction) of the tricycle 200 along the opening 32.

[0029] As shown in Figures 2 and 4, the suspension bracket 4 comprises an upper connection portion 41, a main bracket 42, a lower connection portion 43, and a frame connection portion 44. The upper connection portion 41 includes an upper connection shaft 41a extending in the direction of travel (Y direction) of the tricycle 200. The lower connection portion 43 includes a pair of lower connection shafts 43a extending in the direction of travel (Y direction) of the tricycle 200. The pair of lower connection shafts 43a have a symmetrical structure on one side (X2 side) and the other side (X1 side) in the vehicle width direction of the tricycle 200. The upper connection portion 41 is provided on the upper side (Z1 side) of the main bracket 42, and the lower connection portion 43 is provided on the lower side (Z2 side) of the main bracket 42. The main bracket 42 is connected to the frame 203 via the frame connection portion 44.

[0030] The end of the upper arm 2 on the other side (X1 side) in the vehicle width direction of the tricycle 200 and the upper connecting shaft 41a are connected so as to be relatively rotatable about axis C4 of the upper connecting shaft 41a. The end of the lower arm 3 on the other side (X1 side) in the vehicle width direction of the tricycle 200 and the lower connecting shaft 43a are connected so as to be relatively rotatable about axis C5 of the lower connecting shaft 43a. For convenience of illustration, only the other side (X1 side) in the vehicle width direction of the tricycle 200 of the lower connecting shaft 43a is visible in Figure 2.

[0031] The knuckle arm 1, upper arm 2, lower arm 3, and suspension bracket 4 connected as described above are configured with a link mechanism so that, as shown in Figure 6, the two front wheels 201 are tilted in the width direction (X direction) of the tricycle 200 with respect to the vertical direction (Z direction) of the frame 203 in accordance with the tilt of the tricycle 200 in the width direction (X direction) with respect to the vertical direction (Z direction) of the frame 203. Hereinafter, the tilt angle of the two front wheels 201 is defined as the angle formed by the two front wheels 201 that are not tilted as shown in Figure 4 and the two front wheels 201 that are tilted as shown in Figure 6. The knuckle arm 1, upper arm 2, lower arm 3, and suspension bracket 4 connected as described above are an example of a "tilt mechanism" in the claims.

[0032] 7, when the two front wheels 201 are tilted in the width direction (X direction) of the tricycle 200 with respect to the vertical direction (Z direction), the steering angles α and β of the two front wheels 201 are the angles formed by axis D, which is the direction in which the two front wheels 201 face when the two front wheels 201 are not tilted in the width direction (X direction) of the tricycle 200 with respect to the vertical direction (Z direction), and axis S1 and S2, which are the direction in which the two front wheels 201 face when the two front wheels 201 are tilted in the width direction (X direction) of the tricycle 200 with respect to the vertical direction (Z direction). In this embodiment, the steering angle difference between the two front wheels 201 when the two front wheels 201 are tilted in the width direction (X direction) of the tricycle 200 with respect to the vertical direction (Z direction), is taken to be |α-β|.

[0033] As shown in Figures 2, 4, and 6, the damper 5 includes a damper arm 51. The damper arm 51 includes an upper damper shaft 51a on its upper side (Z1 side) that extends in the direction of travel (Y direction) of the tricycle 200. The end of the damper 5 on one side (X2 side) in the vehicle width direction of the tricycle 200 and the upper damper shaft 51a are connected so as to be relatively rotatable about axis C6 of the upper damper shaft 51a. Furthermore, the end of the damper arm 51 on its lower side (Z2 side) and the lower connecting shaft 43a are connected so as to be relatively rotatable about axis C5 of the lower connecting shaft 43a. As shown in FIG. 6, the damper 5 is configured to absorb vibrations and shocks caused by road surface conditions when the two front wheels 201 are tilted in the width direction (X direction) of the tricycle 200 relative to the vertical direction (Z direction), thereby attenuating the vibrations and shocks transmitted to the operator (not shown).

[0034] As shown in Figures 3 and 5, the rotating unit 7 includes a front-wheel pulley 71 and a rotating bracket 72. The front-wheel pulley 71 is configured to rotate about an axis C1 that is perpendicular to the direction of travel (Y direction) of the tricycle 200 and the widthwise direction (X direction) of the tricycle 200. A wire 8 is fitted into the front-wheel pulley 71. The wire 8 is configured to be tensioned in response to steering of the tricycle 200. The rotating bracket 72 is located below the front-wheel pulley 71 (Z2 side), and is configured to rotate about the axis C1 as the front-wheel pulley 71 rotates. A connection point 61 between the end of the tie rod 6 on one side (X2 side) in the widthwise direction of the tricycle 200 and the lower side (Z2 side) of the knuckle arm 1 is connected by, for example, a ball joint. Furthermore, the connection point 62 between the end of the tie rod 6 on the other side (X1 side) in the vehicle width direction of the tricycle 200 and the pivot bracket 72 is connected by, for example, a ball joint. The front wheel pulley 71 is an example of a "first pulley" in the claims. The wire 8 is an example of a "string-like member" in the claims. The axis C1 is an example of a "first axis" and a "rotation axis of the first pulley" in the claims.

[0035] The knuckle arms 1, tie rods 6, and rotating unit 7 connected as described above are configured to have a link mechanism, which changes the steering angle of the two front wheels 201 using the wire 8 to which tension is applied in response to steering of the tricycle 200. Here, the wire 8 is fitted into the front-wheel-side pulley 71, and the tensioned wire 8 rotates the front-wheel-side pulley 71 (rotating unit 7) about the axis C1. The rotated rotating unit 7 then pushes and pulls the tie rod 6, thereby changing the steering angle of the two front wheels 201. The link mechanism formed by the knuckle arms 1, tie rods 6, and rotating unit 7 connected as described above is a so-called parallel steering mechanism, in which the steering angles of the two front wheels 201 are approximately the same when turning. Note that the knuckle arms 1, tie rods 6, and rotating unit 7 connected as described above are an example of a "steering mechanism" in the claims.

[0036] (Adjustment of inter-arm angle θ and arm length ratio a / b) Next, adjustment of the inter-arm angle θ and the arm length ratio a / b according to one embodiment of the present invention will be described with reference to Figures 10 to 14. For convenience of explanation, the other side (X1 side) in the vehicle width direction of tricycle 200 is omitted from Figure 10.

[0037] The adjustment of the inter-arm angle θ and the arm length ratio a / b is carried out based on data obtained by the simulation shown in Figures 11 to 14. The inventors of the present application have confirmed that data similar to the data obtained by the simulation shown in Figures 11 to 14 can also be obtained from experiments using an actual device.

[0038] As shown in Figure 10, the inventors of the present application conducted a simulation using as variables the arm length ratio a / b, which is the ratio of the length a of the lower arm 3 along the extension direction to the length b of the tie rod 6 along the extension direction when viewed from the direction of travel of the tricycle 200 (direction Y2), and the inter-arm angle θ, which is the angle between the axis LL along the extension direction of the lower arm 3 and the axis LT along the extension direction of the tie rod 6 when viewed from the direction of travel of the tricycle 200 (direction Y2) with the two front wheels 201 not tilted and upright. Note that the length a along the extension direction of the lower arm 3 is an example of the "length a of the lower arm portion" in the claims. Note that the length b along the extension direction of the tie rod 6 is an example of the "length b of the steering arm portion" in the claims.

[0039] The relationship between the arm length ratio a / b and the difference in steering angle between the two front wheels 201 when they are tilted 25° in the case where the inter-arm angle θ=0° is represented by the solid line in Fig. 11. The dashed-dotted line in Fig. 11 indicates the line where the difference in steering angle between the two front wheels 201 when they are tilted 25° is 10°. In other words, within the range r4 where the arm length ratio a / b is 0.725≦a / b≦1.15, the difference in steering angle between the two front wheels 201 when they are tilted 25° is within 10°.

[0040] As shown in Figure 12, when the two front wheels 201 are tilted 25° at θ = -10°, -5°, -2.5°, 0°, 2.5°, 5°, and 10°, the ranges of a / b (first range r1, second range r2, third range r3, fourth range r4, fifth range r5, sixth range r6, and seventh range r7) within which the steering angle difference is within 10° are different for each range. Specifically, the first range r1 is 0.72 ≦ a / b ≦ 1.08. The second range r2 is 0.73 ≦ a / b ≦ 1.15. The third range r3 is 0.73 ≦ a / b ≦ 1.16. The fourth range r4 is 0.725 ≦ a / b ≦ 1.15. The fifth range r5 is 0.72 ≦ a / b ≦ 1.12. The sixth range r6 is 0.71≦a / b≦1.08. The seventh range r7 is 0.75≦a / b≦0.98. As shown in FIG. 10, when the lower arm 3 and tie rod 6 move closer to each other in the width direction of the tricycle 200 (X2 direction) as viewed from the direction of travel of the tricycle 200 (Y2 direction), the inter-arm angle θ takes a negative value. When the lower arm 3 and tie rod 6 move farther apart in the width direction of the tricycle 200 (X2 direction) as viewed from the direction of travel of the tricycle 200 (Y2 direction), the inter-arm angle θ takes a positive value.

[0041] In this embodiment, the inter-arm angle θ and the arm length ratio a / b are adjusted to fall within a region R between a line R1 connecting the minimum values of the first range r1, the second range r2, the third range r3, the fourth range r4, the fifth range r5, the sixth range r6, and the seventh range r7, and a line R2 connecting the maximum values of the first range r1, the second range r2, the third range r3, the fourth range r4, the fifth range r5, the sixth range r6, and the seventh range r7. Note that lines R1 and R2 are represented by dashed lines in FIG. 12. Region R is the hatched region in FIG. 12. Note that the first range r1 to the seventh range r7 are an example of the "range of the arm length ratio a / b" in the claims.

[0042] In this embodiment, as shown in FIG. 13 , more preferably, the inter-arm angle θ and the arm length ratio a / b are adjusted to be within a range defined by region A, region B, and region C. Also, more preferably, the inter-arm angle θ and the arm length ratio a / b are adjusted to be within a range defined by region B and region C. Also, more preferably, the inter-arm angle θ and the arm length ratio a / b are adjusted to be within a range defined by region B and region C. In region A, the inter-arm angle θ is −10°≦θ≦10°, and the arm length ratio a / b is 0.76≦a / b≦0.96. In region B, the inter-arm angle θ is −10°≦θ≦2.5°, and the arm length ratio a / b is 0.74≦a / b≦1.06. In region C, the inter-arm angle θ is −5°≦θ≦0°, and the arm length ratio a / b is 0.74≦a / b≦1.14. Note that area A is an example of the "first area" in the claims. Area B is an example of the "second area" in the claims. Area C is an example of the "third area" in the claims.

[0043] 14, the smaller the inclination angle of the two front wheels 201, the larger the range of the arm length ratio a / b in which the difference in steering angle between each of the two front wheels 201 is within 10°. Specifically, the area between line R3 connecting the minimum values of the range of the arm length ratio a / b in which the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 20°, and line R4 connecting the maximum values of the range of the arm length ratio a / b in which the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 20°, is larger than area R. Furthermore, the area between line R5 connecting the minimum value of the range of arm length ratio a / b where the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 15° and line R6 connecting the maximum value of the range of arm length ratio a / b where the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 15° is larger than the area when the inclination angle is 20°. Furthermore, the area between line R7 connecting the minimum value of the range of arm length ratio a / b where the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 10° and line R8 connecting the maximum value of the range of arm length ratio a / b where the difference in steering angle between each of the two front wheels 201 is within 10° when the inclination angle of the two front wheels 201 is 10° is larger than the area when the inclination angle is 15°. The line R7 is an example of the "minimum line" in the claims, and the line R8 is an example of the "maximum line" in the claims.

[0044] Specifically, in the region between line R3 and line R4, when the inter-arm angle θ=−10°, 0.54≦a / b≦1.18; when the inter-arm angle θ=−5°, 0.53≦a / b≦1.23; when the inter-arm angle θ=−2.5°, 0.52≦a / b≦1.24; when the inter-arm angle θ=0°, 0.52≦a / b≦1.22; when the inter-arm angle θ=2.5°, 0.51≦a / b≦1.19; when the inter-arm angle θ=5°, 0.53≦a / b≦1.15; and when the inter-arm angle θ=10°, 0.63≦a / b≦1.05.

[0045] Specifically, in the region between line R5 and line R6, when the inter-arm angle θ=−10°, 0.05≦a / b≦1.32; when the inter-arm angle θ=−5°, 0.15≦a / b≦1.4; when the inter-arm angle θ=−2.5°, 0.2≦a / b≦1.39; when the inter-arm angle θ=0°, 0.28≦a / b≦1.39; when the inter-arm angle θ=2.5°, 0.37≦a / b≦1.35; when the inter-arm angle θ=5°, 0.43≦a / b≦1.29; and when the inter-arm angle θ=10°, 0.56≦a / b≦1.16.

[0046] Specifically, in the region between line R7 and line R8, when the inter-arm angle θ=−10°, 0.05≦a / b≦1.56; when the inter-arm angle θ=−5°, 0.06≦a / b≦1.69; when the inter-arm angle θ=−2.5°, 0.13≦a / b≦1.72; when the inter-arm angle θ=0°, 0.19≦a / b≦1.69; when the inter-arm angle θ=2.5°, 0.27≦a / b≦1.63; when the inter-arm angle θ=5°, 0.35≦a / b≦1.56; and when the inter-arm angle θ=10°, 0.49≦a / b≦1.42.

[0047] The inventors of the present invention carried out the simulation under the following conditions. As shown in FIG. 10, the length a along the extension direction of the lower arm 3 is set to 165 mm. The axis LL along the extension direction of the lower arm 3 shown in FIG. 10 is parallel to the installation surface of the two front wheels 201. As shown in FIG. 10, the distance d between the end point of the lower arm 3 on the inner side (X1 side) in the vehicle width direction of the tricycle 200 and the end point of the tie rod 6 on the inner side (X1 side) in the vehicle width direction of the tricycle 200 is set to 25 mm. As shown in FIG. 10, the straight line connecting the end point of the lower arm 3 on the inner side (X1 side) in the vehicle width direction of the tricycle 200 and the end point of the tie rod 6 on the inner side (X1 side) in the vehicle width direction of the tricycle 200 is perpendicular to the installation surface of the two front wheels 201. When viewed from the direction of travel of the tricycle 200 (Y2 direction), the tie rod 6 is disposed below the lower arm 3 (Z2 side) or at the same height. As shown in Figure 5, the distance e along the direction of travel (Y direction) of the tricycle 200 between the ball joint shaft 12 and the connection point 62 between the end of the tie rod 6 on the other side (X1 side) in the vehicle width direction of the tricycle 200 and the pivot bracket 72 is 187.8 mm. As shown in Figure 5, the distance f along the direction of travel (Y direction) of the tricycle 200 between the ball joint shaft 12 and the connection point 61 between the end of the tie rod 6 on one side (X2 side) in the vehicle width direction of the tricycle 200 and the lower side (Z2 side) of the knuckle arm 1 is 124.5 mm.

[0048] (Configuration of steering mechanism) Next, the configuration of the steering mechanism of the tricycle 200 according to one embodiment of the present invention will be described with reference to FIGS.

[0049] As shown in FIG. 15, the handle-side pulley 9 is provided below the handle 202 (Z2 side) and in the direction in which the tricycle 200 of the suspension system 100 moves backward (Y1 direction). The handle-side pulley 9 is disposed below the frame 203 (Z2 side) and is configured to rotate about an axis C3 that is perpendicular to the direction of travel of the tricycle 200 (Y direction) and the width direction of the tricycle 200 (X direction). A wire 8 is fitted into the handle-side pulley 9. The handle-side pulley 9 is configured to rotate about the axis C3 when an operator (not shown) operates (steers) the handle 202. The handle-side pulley 9 applies tension to the wire 8 by rotating about the axis C3. The handle-side pulley 9 is an example of a "second pulley" in the claims. The axis C3 is an example of the "rotation axis of the second pulley" in the claims.

[0050] As shown in Figures 15 and 16(a), the tension adjustment unit 13 is provided between the front wheel side pulley 71 and the handle side pulley 9. The tension adjustment unit 13 is located on the lower side (Z2 side) of the frame 203 and is configured to slidably hold the wire 8. The tension adjustment unit 13 includes a first adjustment unit 13a and a second adjustment unit 13b. The first adjustment unit 13a is configured to hold the wire 8 located on the other side (X1 side) in the vehicle width direction of the tricycle 200. The second adjustment unit 13b is configured to hold the wire 8 located on one side (X2 side) in the vehicle width direction of the tricycle 200.

[0051] 16(b), tension adjustment unit 13 is configured to apply tension to wire 8 by first adjustment unit 13a and second adjustment unit 13b moving relatively closer to each other along the vehicle width direction (X direction) of tricycle 200. First adjustment unit 13a and second adjustment unit 13b are configured to apply tension to wire 8 by pressing on wire 8 as they move relatively closer to each other along the vehicle width direction (X direction) of tricycle 200.

[0052] As shown in Figures 16(a) and 16(b), the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts have a non-circular shape when viewed from the direction of their respective rotation axes. Specifically, the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts have an elliptical shape in which the major axis length is twice the minor axis length. The portion of the front-wheel-side pulley 71 where the wire 8 contacts has an elliptical shape that extends along the direction of travel of the tricycle 200 (Y direction) when not being steered. The portion of the handle-side pulley 9 where the wire 8 contacts has an elliptical shape that extends along the width direction of the tricycle 200 (X direction) when not being steered.

[0053] As shown in Fig. 17, the relationship between the rotation angles of the handle-side pulley 9 and the front-wheel-side pulley 71 in this embodiment is non-linear. Specifically, when the rotation angle of the handle-side pulley 9 is relatively small, the rotation angle of the front-wheel-side pulley 71, which rotates in response to the rotation of the handle-side pulley 9, is relatively small. On the other hand, when the rotation angle of the handle-side pulley 9 is relatively large, the rotation angle of the front-wheel-side pulley 71, which rotates in response to the rotation of the handle-side pulley 9, is relatively large. Note that the dashed dotted line in Fig. 17 indicates the relationship between the rotation angles of the handle-side pulley 9 and the front-wheel-side pulley 71 when both the handle-side pulley 9 and the front-wheel-side pulley 71 have circular shapes and are equal in diameter.

[0054] (Effects of the embodiment) Next, the effects of the embodiment will be described.

[0055] In this embodiment, as described above, the arm length ratio a / b, which is the ratio between the length a of the lower arm 3 as viewed from the direction of travel and the length b of the tie rod 6, and the inter-arm angle θ, which is the angle between the lower arm 3 and the tie rod 6 as viewed from the direction of travel when the two front wheels 201 are upright and not tilted by the tilt mechanism, are adjusted so that the difference in steering angle between the two front wheels 201, which is caused by tilting the two front wheels 201 in the vehicle width direction with respect to the vertical direction, is within 10°. As a result, it is possible to reduce the discomfort felt by the operator due to the difference in steering angle between the two front wheels 201.

[0056] Furthermore, in this embodiment, as described above, in a graph with the inter-arm angle θ on the horizontal axis and the arm length ratio a / b on the vertical axis, the inter-arm angle θ and the arm length ratio a / b are adjusted based on the range of the arm length ratio a / b in which the difference in steering angle between the two front wheels 201 caused by the tilt mechanism tilting the two front wheels 201 by 10° to 25°, obtained through experiments or simulations, is within 10°, so that the arm length ratio a / b when |θ|, the absolute value of the inter-arm angle θ, is |θ|≦10°, falls within the range of region R between the minimum line connecting the minimum values in the range of the arm length ratio a / b and the maximum line connecting the maximum values in the range of the arm length ratio a / b. This makes it possible to easily adjust the inter-arm angle θ and the arm length ratio a / b.

[0057] In addition, in this embodiment, as described above, the tilt mechanism and the steering mechanism are configured to have a structure in which one side and the other side in the vehicle width direction are line-symmetrical when viewed from the traveling direction, and in the graph above, the inter-arm angle θ becomes positive when the lower arm 3 and the tie rod 6 spread outward in the vehicle width direction when viewed from the traveling direction on one side in the vehicle width direction, and becomes negative when the lower arm 3 and the tie rod 6 move closer to each other toward the outside in the vehicle width direction when viewed from the traveling direction. The inter-arm angle θ and the arm length ratio a / b are adjusted so that they fall within a range defined by: region A where the inter-arm angle θ is -10°≦θ≦10° and the arm length ratio a / b is 0.76≦a / b≦0.96, region B where the inter-arm angle θ is -10°≦θ≦2.5° and the arm length ratio a / b is 0.74≦a / b≦1.06, and region C where the inter-arm angle θ is -5°≦θ≦0° and the arm length ratio a / b is 0.74≦a / b≦1.14. This clarifies the adjustment ranges of the inter-arm angle θ and the arm length ratio a / b, making it easier to adjust the inter-arm angle θ and the arm length ratio a / b. Furthermore, since the tilt mechanism and steering mechanism have a structure that is linearly symmetrical on one side and the other side in the vehicle width direction when viewed from the direction of travel, the movement of each of the two front wheels 201 due to tilting and steering is approximately the same, thereby reducing the discomfort felt by the operator due to the different movement of each of the two front wheels 201 due to tilting and steering.

[0058] Furthermore, in this embodiment, as described above, the inter-arm angle θ and the arm length ratio a / b are adjusted so as to fall within the range of the region formed by region B and region C in the graph. Here, when the inter-arm angle θ is 2.5°<θ≦10°, the change in the steering angle of the two front wheels 201 caused by the tilt mechanism tilting the two front wheels 201 by 25° includes a relatively large change in the direction opposite to the direction in which the two front wheels 201 are tilted (turning direction). Therefore, by adjusting the inter-arm angle θ and the arm length ratio a / b so that the inter-arm angle θ is within the range formed by area B and area C, which are within the range of -10°≦θ≦2.5°, the change in the steering angle of the two front wheels 201 caused by the tilt mechanism tilting the two front wheels 201 by 25° will no longer include a relatively large change in the direction opposite to the direction in which the front wheels are tilted (turning direction), and therefore it is possible to effectively suppress the discomfort felt by the operator due to the difference in the steering angle of each of the two front wheels 201 caused by tilting the two front wheels 201 in the vehicle width direction relative to the vertical direction.

[0059] Furthermore, in this embodiment, as described above, the inter-arm angle θ and the arm length ratio a / b are adjusted so as to fall within the range of region C in the graph. Here, when the inter-arm angle θ is -10°≦θ<-5°, the change in the steered angle of the two front wheels 201 caused by the tilt mechanism tilting the two front wheels 201 by 25° is relatively large compared to when the inter-arm angle θ is -5°≦θ≦0°. Furthermore, when the inter-arm angle θ is 0°<θ≦2.5°, unlike when the inter-arm angle θ is -5°≦θ≦0°, the change in the steered angle of the two front wheels 201 caused by the tilt mechanism tilting the two front wheels 201 by 25° includes a change in the direction opposite to the direction in which the two front wheels are tilted (the turning direction). Therefore, by adjusting the inter-arm angle θ and the arm length ratio a / b so that the inter-arm angle θ is within the range of region C where -5°≦θ≦0°, it is possible to effectively suppress the discomfort felt by the operator due to the difference in steering angle between the two front wheels 201 caused by tilting the two front wheels 201 in the vehicle width direction relative to the vertical direction.

[0060] Furthermore, in this embodiment, as described above, the tilt mechanism is made up of a link mechanism including two knuckle arms 1, upper arms 2 connected to the upper sides of each of the two knuckle arms 1, lower arms 3 connected to the lower sides of each of the two knuckle arms 1, and suspension brackets 4 connecting the upper arms 2 and lower arms 3 and connected to frame 203 of tricycle 200, while the steering mechanism is made up of a link mechanism including two knuckle arms 1, tie rod 6, and a rotating part 7 that is rotatable about axis C1 that is perpendicular to the traveling direction and the vehicle width direction and connects suspension brackets 4 and tie rod 6. As a result, since the tilt mechanism and steering mechanism are made up of a link mechanism, the tilt mechanism and steering mechanism can be made up of a relatively simple structure.

[0061] Furthermore, in this embodiment, as described above, the two knuckle arms 1 include the ball joint shafts 11 and 12 connected to the upper arm 2 and the lower arm 3, and the ball joint shafts 11 and 12 are restricted from swinging in any direction other than the vehicle width direction. This allows the link mechanism to restrict the tilt of the two front wheels 201 in the vehicle width direction, thereby suppressing any discomfort felt by the operator due to the two front wheels 201 tilting in any direction other than the vehicle width direction.

[0062] Furthermore, in this embodiment, as described above, the steering mechanism includes the front-wheel pulley 71 into which the wire 8 is fitted, and which is tensioned in response to steering of the tricycle 200. The portion of the front-wheel pulley 71 that contacts the wire 8 has a non-circular shape when viewed from the direction of the rotation axis of the front-wheel pulley 71. This makes it possible to adjust the relationship between the steering angle and the steering angles of the two front wheels 201 that change in response to steering in a non-linear manner, thereby optimizing the relationship between the steering angle and the steering angles of the two front wheels 201 that change in response to steering in response to the operator's steering situation. As a result, usability (user convenience) can be improved. Furthermore, because the above-mentioned adjustments can be made simply by changing the shape of the front-wheel pulley 71, the design work can be simplified compared to when complex geometric design is required.

[0063] Furthermore, as described above, this embodiment further includes a handle-side pulley 9 that applies tension to the wire 8 by rotating in response to steering of the tricycle 200, and the portion of the handle-side pulley 9 that contacts the wire 8 has a non-circular shape when viewed from the direction of the rotation axis of the handle-side pulley 9. As a result, in addition to the front-wheel-side pulley 71, the portion of the handle-side pulley 9 that contacts the wire 8 has a non-circular shape. Therefore, compared to when only the portion of the front-wheel-side pulley 71 that contacts the wire 8 has a non-circular shape, the relationship between the steering angle and the steering angles of the two front wheels 201 that change in response to steering can be adjusted more non-linearly. This makes it possible to more optimally adjust the relationship between the steering angle and the steering angles of the two front wheels 201 that change in response to steering in response to the operator's steering situation. As a result, usability (user convenience) can be further improved. Furthermore, because the above-mentioned adjustments can be made simply by changing the shapes of the front-wheel-side pulley 71 and the handle-side pulley 9, the design work can be simplified compared to when complex geometric design is required.

[0064] Furthermore, as described above, this embodiment further includes a tension adjustment unit 13 that presses the wire 8 fitted into the front wheel side pulley 71 having a non-circular shape, and the tension adjustment unit 13 is configured to apply tension to the wire 8 by pressing the wire 8. This prevents a decrease in the tension of the wire 8 that would cause the operator to feel uncomfortable when turning, and also prevents the wire 8 from coming off the front wheel side pulley 71, making it impossible to travel. As a result, it is possible to effectively improve traveling stability when turning.

[0065] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0066] For example, while the above embodiment shows an example in which the vehicle is a tricycle 200, the present invention is not limited to this. For example, the vehicle may be a bicycle with two front wheels, a saddle-type vehicle such as a motorcycle or tricycle, a kick scooter, or a recumbent bicycle.

[0067] Furthermore, in the above embodiment, an example was shown in which the inter-arm angle θ and the arm length ratio a / b were adjusted based on data obtained by simulation, but the present invention is not limited to this. For example, the inter-arm angle θ and the arm length ratio a / b may be adjusted based on data obtained by experiments using an actual device. Furthermore, for example, the inter-arm angle θ and the arm length ratio a / b may be adjusted based on data calculated without using a calculator or the like.

[0068] In addition, in the above embodiment, an example was shown in which the inter-arm angle θ and the arm length ratio a / b were adjusted within the range of -10°≦θ≦10°, but the present invention is not limited to this. For example, the inter-arm angle θ and the arm length ratio a / b may be adjusted within a range in which the inter-arm angle θ is outside the range of -10°≦θ≦10°.

[0069] In the above embodiment, an example was shown in which there were seven pieces of data (first range r1, second range r2, third range r3, fourth range r4, fifth range r5, sixth range r6, and seventh range r7) regarding the ranges of a / b in which the difference in steering angle between the two front wheels 201 when tilted by 25° is within 10°, obtained by simulation, but the present invention is not limited to this. For example, there may be pieces of data other than seven pieces of data regarding the ranges of a / b in which the difference in steering angle between the two front wheels 201 when tilted by 25° is within 10°, obtained by simulation.

[0070] Furthermore, in the above embodiment, the knuckle arm 1, upper arm 2, lower arm 3, suspension bracket 4, damper 5, tie rod 6, and rotating part 7 are shown as being line-symmetrical with respect to the center line C2 that divides the tricycle 200 into one side and the other in the vehicle width direction (X direction) when viewed from the direction of travel of the tricycle 200 (Y2 direction), but the present invention is not limited to this. For example, the knuckle arm 1, upper arm 2, lower arm 3, suspension bracket 4, damper 5, tie rod 6, and rotating part 7 do not have to be line-symmetrical with respect to the center line C2 that divides the tricycle 200 into one side and the other in the vehicle width direction (X direction) when viewed from the direction of travel of the tricycle 200 (Y2 direction).

[0071] In addition, in the above embodiment, an example has been shown in which the tilt mechanism is configured by the connected knuckle arm 1, upper arm 2, lower arm 3, and suspension bracket 4, but the present invention is not limited to this. For example, the tilt mechanism may have any configuration as long as it includes at least the lower arm 3.

[0072] In the above embodiment, the steering mechanism is configured by the connected knuckle arm 1, tie rod 6, and rotating unit 7, but the present invention is not limited to this. For example, the steering mechanism may have any configuration as long as it includes at least the tie rod 6.

[0073] Furthermore, in the above embodiment, an example was shown in which the swinging of ball joint shafts 11 and 12 was restricted in directions other than the width direction (X direction) of tricycle 200, but the present invention is not limited to this. For example, ball joint shafts 11 and 12 may be configured to swing in directions other than the width direction (X direction) of tricycle 200.

[0074] In the above embodiment, the tie rod 6 is operated by the pulleys (the front wheel side pulley 71 and the handle side pulley 9) and the wire 8, but the present invention is not limited to this. For example, the steering power may be transmitted to the tie rod 6 without passing through the pulleys (the front wheel side pulley 71 and the handle side pulley 9) and the wire 8.

[0075] In addition, in the above embodiment, an example was shown in which the portion of the front-wheel-side pulley 71 that contacts the wire 8 and the portion of the handlebar-side pulley 9 that contacts the wire 8 have a non-circular shape, but the present invention is not limited to this. For example, the portion of the front-wheel-side pulley 71 that contacts the wire 8 and the portion of the handlebar-side pulley 9 that contacts the wire 8 may have a circular shape. Furthermore, for example, either the portion of the front-wheel-side pulley 71 that contacts the wire 8 or the portion of the handlebar-side pulley 9 that contacts the wire 8 may have a non-circular shape, and the other may have a circular shape.

[0076] In addition, in the above embodiment, an example has been shown in which tension is applied to the wire 8 by the tension adjustment unit 13, but the present invention is not limited to this. For example, the tension adjustment unit 13 may not apply tension to the wire 8, but may instead hold the wire 8 so that it can slide. Also, for example, the tension adjustment unit 13 may not be provided.

[0077] In the above embodiment, the tension adjuster 13 holds the wire 8 slidably, but the present invention is not limited to this. For example, the tension adjuster 13 does not have to hold the wire 8 slidably.

[0078] Furthermore, in the above embodiment, an example was shown in which there is one tension adjusting unit 13, but the present invention is not limited to this. For example, there may be a plurality of tension adjusting units 13.

[0079] Furthermore, in the above embodiment, an example was shown in which tension adjustment unit 13 applies tension to wire 8 by moving first adjustment unit 13a and second adjustment unit 13b relatively closer to each other along the vehicle width direction (X direction) of tricycle 200, but the present invention is not limited to this. For example, tension adjustment unit 13 may be configured to apply tension to wire 8 by moving first adjustment unit 13a and second adjustment unit 13b relatively farther apart along the vehicle width direction (X direction) of tricycle 200.

[0080] Furthermore, in the above embodiment, an example was shown in which the portion of the front-wheel-side pulley 71 with which the wire 8 contacts has an elliptical shape extending along the direction of travel (Y direction) of the tricycle 200 when not being steered, and the portion of the handlebar-side pulley 9 with which the wire 8 contacts has an elliptical shape extending along the width direction (X direction) of the tricycle 200 when not being steered, but the present invention is not limited to this. For example, as shown in Figure 18, the portion of the front-wheel-side pulley 71 with which the wire 8 contacts may have an elliptical shape extending along the width direction (X direction) of the tricycle 200 when not being steered, and the portion of the handlebar-side pulley 9 with which the wire 8 contacts may have an elliptical shape extending along the direction of travel (Y direction) of the tricycle 200 when not being steered. In this case, the relationship between the rotation angles of the handlebar-side pulley 9 and the front-wheel-side pulley 71 is as shown in Figure 19. Specifically, when the rotation angle of the handlebar side pulley 9 is relatively small, the rotation angle of the front wheel side pulley 71, which rotates in response to the rotation of the handlebar side pulley 9, is relatively large. On the other hand, when the rotation angle of the handlebar side pulley 9 is relatively large, the rotation angle of the front wheel side pulley 71, which rotates in response to the rotation of the handlebar side pulley 9, is relatively small. Note that the dashed dotted line in Figure 19 shows the relationship between the rotation angles of the handlebar side pulley 9 and the front wheel side pulley 71 when both the handlebar side pulley 9 and the front wheel side pulley 71 have circular shapes and are the same diameter.

[0081] In the above embodiment, the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts have an elliptical shape in which the major axis is twice the length of the minor axis, but the present invention is not limited to this. For example, the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts may have an elliptical shape in which the major axis is not twice the length of the minor axis. Also, for example, the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts may have a diamond shape as shown in FIG. 20(a). Also, for example, the portion of the front-wheel-side pulley 71 where the wire 8 contacts and the portion of the handle-side pulley 9 where the wire 8 contacts may have a barrel shape as shown in FIG. 20(b). Furthermore, for example, the portion of the front wheel side pulley 71 that contacts the wire 8 and the portion of the handle side pulley 9 that contacts the wire 8 may have an oval shape as shown in FIG. 20(c).

[0082] In the above embodiment, the tension adjuster 13 applies tension to the wire 8 using the first adjuster 13a and the second adjuster 13b, but the present invention is not limited to this. For example, as shown in Fig. 21, the tension adjuster 13 may be formed of an annular elastic member. In this case, the tension adjuster 13 may be configured to apply tension to the wire 8 by bundling two wires 8 together using the annular elastic member.

[0083] In addition, in the above embodiment, an example has been shown in which a pair of upper arms 2 are provided, but the present invention is not limited to this. For example, the upper arm 2 may be configured as a single arm that connects a pair of knuckle arms 1.

[0084] In addition, in the above embodiment, an example has been shown in which a pair of lower arms 3 are provided, but the present invention is not limited to this. For example, the lower arm 3 may be configured as a single arm that connects a pair of knuckle arms 1.

[0085] In addition, in the above embodiment, an example was shown in which the two front wheels 201 are configured to tilt in accordance with the tilt of the frame 203, but the present invention is not limited to this. For example, the two front wheels 201 may be tilted in accordance with an operation performed by the operator other than the tilt of the frame 203.

[0086] Furthermore, in the above embodiment, the wire 8 is used as the string-like member, but the present invention is not limited to this. For example, a chain, a belt, or the like may be used as the string-like member.

[0087] Furthermore, in the above embodiment, an example was shown in which the inter-arm angle θ and the arm length ratio a / b were adjusted so that they lie between a line R1 connecting the minimum value and a line R2 connecting the maximum value of the range of the arm length ratio a / b in which the difference in steering angle between the two front wheels 201 when the inclination angle of the two front wheels 201 is 25° and within 10°, but the present invention is not limited to this. For example, it is sufficient that the inter-arm angle θ and the arm length ratio a / b are adjusted so that they lie between a line connecting the minimum value and a line connecting the maximum value of the range of the arm length ratio a / b in which the difference in steering angle between the two front wheels 201 when the inclination angle of the two front wheels 201 is 0° to 25° and within 10°. Furthermore, for example, the inter-arm angle θ and the arm length ratio a / b may be adjusted so that they are between line R7 connecting the minimum values and line R8 connecting the maximum values of the range of arm length ratio a / b in which the steering angle difference between each of the two front wheels 201 when the inclination angle of the two front wheels 201 is 10° is within 10°. [Explanation of symbols]

[0088] 1 Knuckle arm (suspended part) 2 Upper arm (upper arm part) 3 Lower arm (lower arm part) 4. Suspension bracket (main body) 6 Tie rod (steering arm) 7 Rotating part 8 Wire (string-like member) 9. Handle side pulley (second pulley) 11, 12 Ball joint axis (joint) 13 Tension adjustment section 71 Front wheel pulley (first pulley) 200 Tricycle (Vehicle) 201 front wheel 203 frames C1 axis (first axis, rotation axis of first pulley) C3 axis (rotation axis of second pulley) a) Length along the direction in which the lower arm 3 extends (length a of the lower arm part) b Length along the direction in which the tie rod 6 extends (length b of the steering arm) a / b arm length ratio θ angle between arms r1~r7 1st range to 7th range (Arm length ratio a / b range) R1~R6 lines R7 Minimum Line R8 Max Line Area A (first area) B area (second area) Area C (3rd area) α, β Rudder angle

Claims

1. A vehicle having two front wheels that rotate in the direction of travel, a tilt mechanism that tilts the front wheels in a vehicle width direction of the vehicle with respect to a vertical direction and includes a lower arm portion connected to two suspension portions that are connected to the two front wheels, respectively; a steering mechanism including a steering arm portion that changes the steering angle of the front wheels in response to steering of the vehicle and is connected to the two suspension portions so as to be located below the lower arm portion or at the same height as the lower arm portion when viewed from the traveling direction, an arm length ratio a / b, which is the ratio of the length a of the lower arm portion as viewed from the direction of travel to the length b of the steering arm portion, and an arm angle θ, which is the angle formed by the lower arm portion and the steering arm portion as viewed from the direction of travel when the front wheels are not tilted by the tilt mechanism and the vehicle is upright, are adjusted so that the steering angle difference between the two front wheels caused by the tilt mechanism tilting the front wheels is within 10°.

2. 2. The vehicle according to claim 1, wherein, in a graph taking the inter-arm angle θ as the horizontal axis and the arm length ratio a / b as the vertical axis, the inter-arm angle θ and the arm length ratio a / b are adjusted so that when |θ| that is an absolute value of the inter-arm angle θ is |θ|≦10°, the arm length ratio a / b lies between a minimum line connecting minimum values in the range of the arm length ratio a / b and a maximum line connecting maximum values in the range of the arm length ratio a / b, based on a range of the arm length ratio a / b obtained by experiment or simulation in which a steering angle difference between each of the two front wheels caused by the tilt mechanism tilting the front wheels by 10° to 25° is within 10°.

3. the tilt mechanism and the steering mechanism are configured to have a structure in which one side and the other side in the vehicle width direction are line-symmetrical when viewed from the traveling direction, 3. The vehicle according to claim 2, wherein in the graph, on one side in the vehicle width direction, as seen from the direction of travel, the inter-arm angle θ is positive when the lower arm portion and the steering arm portion widen outward in the vehicle width direction and negative when the lower arm portion and the steering arm portion approach each other outward in the vehicle width direction, as seen from the direction of travel, and the inter-arm angle θ and the arm length ratio a / b are adjusted to be within a range defined by: a first region in which the inter-arm angle θ is -10°≦θ≦10° and the arm length ratio a / b is 0.76≦a / b≦0.96; a second region in which the inter-arm angle θ is -10°≦θ≦2.5° and the arm length ratio a / b is 0.74≦a / b≦1.06; and a third region in which the inter-arm angle θ is -5°≦θ≦0° and the arm length ratio a / b is 0.74≦a / b≦1.

14.

4. 4. The vehicle according to claim 3, wherein the inter-arm angle θ and the arm length ratio a / b are adjusted so as to fall within a range defined by the second region and the third region in the graph.

5. The vehicle according to claim 4 , wherein the inter-arm angle θ and the arm length ratio a / b are adjusted so as to fall within the range of the third region in the graph.

6. the tilt mechanism is configured by a first link mechanism including the two suspension parts, an upper arm part connected to the upper side of each of the two suspension parts, a lower arm part connected to the lower side of each of the two suspension parts, and a main body part connecting the upper arm part and the lower arm part and connected to a frame of the vehicle, 2. The vehicle according to claim 1, wherein the steering mechanism is configured by a second link mechanism including the two suspension portions, the steering arm portion, and a rotating portion that is rotatable about a first axis that is perpendicular to the traveling direction and the vehicle width direction and that connects the main body portion and the steering arm portion.

7. the two suspension parts include joint parts connected to the upper arm part and the lower arm part, The vehicle according to claim 6, wherein the joint portion is restricted from swinging in any direction other than the vehicle width direction.

8. the steering mechanism includes a first pulley into which a string-like member is fitted that is tensioned in response to steering of the vehicle; The vehicle according to claim 1 , wherein a portion of the first pulley that comes into contact with the string-like member has a non-circular shape when viewed from the direction of the rotation axis of the first pulley.

9. a second pulley that applies tension to the string-like member by being rotated in response to steering of the vehicle; 9. The vehicle according to claim 8, wherein a portion of the second pulley that comes into contact with the string-like member has a non-circular shape when viewed from the direction of the rotation axis of the second pulley.

10. a tension adjusting unit that presses the string-like member that is fitted onto the first pulley having the non-circular shape, The vehicle according to claim 8 , wherein the tension adjusting portion is configured to apply tension to the string-like member by pressing the string-like member.

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