LEANING VEHICLE

Abstract

A leaning vehicle including a vehicle body, two front wheels, and a support mechanism by which the two front wheels are supported by the vehicle body. The support mechanism includes a joint mechanism that is a ball joint and that includes a ball stud including a ball part connected to a shaft, and a holder having an open end part through which the ball stud is insertable, such that the ball part is freely rotatable in the holder. The open end part includes first to fourth inner edge parts. When the ball stud is in a steering neutral and leaning neutral position, in a direction along a central axis of the ball stud, the first and second inner edge parts do not overlap, and the third and fourth inner edge parts overlap, the ball part. The ball stud is tiltable between the first and second inner edge parts.

Claims

1. A leaning vehicle comprising: a vehicle body that is leanable leftward and rightward; two front wheels that are leanable leftward and rightward together with the vehicle body and are steerable leftward and rightward; and a support mechanism by which the two front wheels are supported by the vehicle body, the support mechanism including: a first member, a second member, and a joint mechanism that connects the first member and the second member in such a manner as to allow the first member and the second member to be displaced relative to each other along with leaning of the two front wheels, and to allow the first member and the second member to be displaced relative to each other along with steering of the two front wheels, wherein the joint mechanism is a ball joint that includes: a ball stud including a spherical ball part connected to a bar-like first shaft, and a metal holder having an open end part through which the ball stud is insertable, such that the ball part is freely rotatable in the holder, the open end part including a first inner edge part and a second inner edge part, and a third inner edge part and a fourth inner edge part, positioned separately from each other between the first and second inner edge parts; and the joint mechanism is so configured that, when the ball stud is in a steering neutral and leaning neutral position, in a direction along a central axis of the ball stud, neither the first inner edge part nor the second inner edge part overlaps the ball part, and both the third inner edge part and the fourth inner edge part overlap the ball part, and when the ball stud is not in the steering neutral and leaning neutral position, the ball stud is tiltable between the first and second inner edge parts.

2. The leaning vehicle according to claim 1, wherein the open end part is so configured that, when the ball stud is in the steering neutral and leaning neutral position, in the direction along the central axis of the ball stud, the first and second inner edge parts are positioned between a center of the ball part and a ball-side end of the first shaft, and the ball-side end of the first shaft is positioned between either of the first and second inner edge parts and either of the third and fourth inner edge parts.

3. The leaning vehicle according to claim 2, wherein the first and second inner edge parts are so configured as to allow the ball stud to tilt within a range off 25 degrees from the central axis of the ball stud when the ball stud is in the steering neutral and leaning neutral position.

4. The leaning vehicle according to claim 3, wherein the open end part is so configured as to limit a tilt angle of the ball stud by contact of the ball stud with a part of the open end part that is other than the first to fourth inner edge parts.

5. The leaning vehicle according to claim 2, wherein the open end part is so configured as to limit a tilt angle of the ball stud by contact of the ball stud with a part of the open end part that is other than the first to fourth inner edge parts.

6. The leaning vehicle according to claim 1, wherein the first and second inner edge parts are so configured as to allow the ball stud to tilt within a range off 25 degrees from the central axis of the ball stud when the ball stud is in the steering neutral and leaning neutral position.

7. The leaning vehicle according to claim 1, wherein the open end part is so configured as to limit a tilt angle of the ball stud by contact of the ball stud with a part of the open end part that is other than the first to fourth inner edge parts.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0037] FIG. 1 is an illustrative diagram including: a perspective view of a leaning vehicle according to an embodiment of the present teaching; a back view and a plan view of a support mechanism of the leaning vehicle; and a perspective view of a ball joint of the leaning vehicle.

[0038] FIG. 2 is an illustrative diagram including: sectional views of the ball joint of the leaning vehicle shown in FIG. 1; and a plan view showing the relationship between a ball part of a ball stud and the inner edge of an open end part of a holder.

[0039] FIG. 3 is an illustrative diagram including: sectional views of conventional ball joints; and a sectional view of the ball joint of the leaning vehicle shown in FIG. 1.

[0040] FIG. 4 is a plan view of a modification of the support mechanism of the leaning vehicle.

DESCRIPTION OF EMBODIMENTS

[0041] A leaning vehicle according to an embodiment of the present teaching will hereinafter be described in detail with reference to the drawings. The embodiment described below is merely an example. The present teaching shall not be understood to be limited to the embodiment below.

[0042] With reference to FIG. 1, a leaning vehicle 5 will be described. FIG. 1 includes: (a) a perspective view of the leaning vehicle 5; (b) a back view of a leaning linkage mechanism 53 contained in the leaning vehicle 5; (c) a plan view of the leaning linkage mechanism 53; and (d) a perspective view of a ball joint 1 that serves as a joint mechanism in the leaning vehicle 5.

[0043] The leaning vehicle 5 includes a vehicle body 54, two front wheels 51F, one single rear wheel 51R, and a support mechanism 52. Various directions relative to the leaning vehicle 5 are directions from the perspective of a rider riding the leaning vehicle 5.

[0044] The vehicle body 54 is capable of leaning to the left and right of the leaning vehicle 5. The two front wheels 51F lean to the left and right of the leaning vehicle 5 together with the vehicle body 54, and are steerable to the left and right of the leaning vehicle 5. The single rear wheel 51R is supported by the vehicle body 54. The single rear wheel 51R leans to the left and right of the leaning vehicle 5 together with the vehicle body 54.

[0045] The support mechanism 52 includes a leaning linkage mechanism 53. The leaning linkage mechanism 53 allows the vehicle body 54 and the two front wheels 51F to lean to the left or right of the leaning vehicle 5 when the leaning vehicle 5 turns left or right. Thus, when the leaning vehicle 5 is turning left or right, the vehicle body 54 and the two steerable wheels 51F lean to the left or right of the leaning vehicle 5.

[0046] The support mechanism 52 includes a steering handlebar 551 to be manipulated by a rider, a steering linkage 552, a swing shaft 553, pitman arms 554, tie rods 555, and knuckles 556. The steering handlebar 551 is swingably supported by the vehicle body. The steering handlebar 551 is connected to the swing shaft 553 via the steering linkage 552. The swing shaft 553 swings around a swing axis extending in the upward-and-downward direction. The pitman arms 554 are supported by the swing shaft 553 in such a manner as to swing together with the swing shaft 553. Each of the tie rods 555 has an end (which will hereinafter be referred to as a first end) that is connected to the corresponding one of the pitman arms 554, and another end (which will hereinafter be referred to as a second end) that is connected to the corresponding one of the knuckles 556. With this mechanism, a swing of the steering handlebar 551 caused by the rider's manipulation is transmitted to the steering linkage 552, the swing shaft 553, the pitman arms 554, the tie rods 555 and then to the knuckles 556. The knuckles 556 swing around a steering axis. Accordingly, the two front wheels 51F swing around the steering axis. Thereby, the two front wheels 51F are steered.

[0047] In the support mechanism 52, the tie rods 555 (which are examples of first members) and the pitman arms 554 (which are examples of second members) are connected by ball joints 1 (which are examples of joint mechanisms). In other words, each of the tie rods 555 is connected to the corresponding one of the pitman arms 554 via a ball joint 1. In a similar manner, the tie rods 555 (which are examples of first members) and the knuckles 556 (which are examples of second members) are connected by ball joints 1. In other words, each of the tie rods 555 is connected to the corresponding one of the knuckles 556 via a ball joint 1.

[0048] The ball joint 1 between each of the tie rods 555 and the corresponding one of the pitman arms 554 connects the tie rod 555 and the pitman arm 554 in such a manner as to allow the tie rod 555 and the pitman arm 554 to be displaced relative to each other along with leaning of the two front wheels 51F and to allow the tie rod 555 and the pitman arm 554 to be displaced relative to each other along with steering of the two front wheels 51F.

[0049] The ball joint 1 between each of the tie rod 555 and the corresponding one of the knuckles 556 connects the tie rod 555 and the knuckle 556 in such a manner as to allow the tie rod 555 and the knuckle 556 to be displaced relative to each other along with leaning of the two front wheels 51F and to allow the tie rod 555 and the knuckle 556 to be displaced relative to each other along with steering of the two front wheels 51F.

[0050] Next, with reference to FIGS. 1 and 2, the ball joint 1 will be described. The ball joint 1 includes a ball stud 3, a holder 2, and a cover 4. FIG. 1 shows the ball joint 1 with the cover 4 removed. FIG. 2 includes: (a) a sectional view of the ball joint 1 along line A-A; (b) a sectional view of the ball joint 1 along line B-B; and (c) a partial plan view of the ball joint 1. FIG. 2(c) omits a slide member 25 for a clear illustration of the relationship between each of a first inner edge part 211, a second inner edge part 212, a third inner edge part 213 and a fourth inner edge part 214 at an open end part 21 and a ball part 31 of the ball stud 3.

[0051] The ball joint 1 is illustrated in a coordinate system in which the leftward-and-rightward direction and the upward-and-downward direction are defined when the open end part of the holder 2 is viewed from a point in the extending direction of the central axis CL of the ball stud 3 in the steering neutral and leaning neutral position. The direction in which the second shaft 22 of the holder 2 extends is defined as the right. Along the central axis CL of the ball stud 3 in the steering neutral and leaning neutral position, the direction from the open end part into the holder 2 is defined as the front. Directions in the coordinate system in which the ball joint 1 is illustrated may be same or may be different with directions in the coordinate system in which the leaning vehicle 5 is illustrated. These two coordinate systems are independent of each other. FIGS. 1 and 2 show the position of the ball stud 3 when the two front wheels 51F are in their respective steering neutral and leaning neutral positions.

[0052] The ball stud 3 includes a spherical ball part 31 and a bar-like first shaft 32. The ball stud 3 is made of metal. The holder 2 holds the ball part 31 in such a manner that the ball part 31 is freely rotatable. The holder 2 is made of metal.

[0053] The holder 2 includes: a body 21 having an open end part 210 pierced by the ball stud 3; a bar-like second shaft 22 having an axis extending rightward; a connection part 23 connecting the body 21 and the second shaft 22; and a cap 24 that defines a space for the ball part 31 in the body 21. After the ball stud 3 is fixed to the body 21, the cap 24 is attached to the body 21 in such a manner as to cover another open end of the body 21. The cap 24 functions as a stopper that stops the ball stud 3 from being pushed into the holder 2 any further. As will be described later, the third inner edge part 213 and the fourth inner edge part 214 function as a stopper that stops the ball stud 3 from being pulled out of the holder 2. Between the body 21 and the ball part 31, a resin slide member 25 is positioned. The resin slide member 25 is formed into a shape that fits in between the body 21 and the ball part 31.

[0054] The cover 4 is elastically deformable. The cover 4 includes a cover body 41, a metal core 42, and a clip 43. The cover body 41 is formed from an elastically deformable material. The metal core 42 is formed integrally with the cover body 41. The first shaft 32 of the ball stud 3 pierces through the metal core 42. The cover 4 elastically deforms when the ball joint 1 tilts.

[0055] The open end part 210 includes at least a first inner edge part 211, a second inner edge part 212, a third inner edge part 213, and a fourth inner edge part 214. The first inner edge part 211 and the second inner edge part 212 are formed at positions outward from the circumference of the maximum width part of the ball part 31 with respect to a direction perpendicular to the central axis CL of the ball stud 3 in its steering neutral and leaning neutral position. The third inner edge part 213 and the fourth inner edge part 214 are formed at positions inward from the circumference of the maximum width part of the ball part 31 with respect to a direction perpendicular to the central axis CL of the ball stud 3 in its steering neutral and leaning neutral position. The third inner edge part 211 and the fourth inner edge part 214 are formed at separate positions between the first inner edge part 211 and the second inner edge part 212.

[0056] The open end part 210 is formed in such a manner that the tilt angle θw of the ball stud 3 varies between the first inner edge part 211 and the second inner edge part 212 when the two front wheels 51F are steered from their respective steering neutral and leaning neutral positions. In other words, in the leaning vehicle 5, the ball joint 1 is arranged in such a manner that the tilt angle θw of the ball stud 3, which is variable between the first inner edge part 211 and the second inner edge part 212, corresponds to the steering angle of the two front wheels 51F.

[0057] The open end part 210 is formed in such a manner that the first inner edge part 211 and the second inner edge part 212 are positioned between the center 31C of the ball part 31 and the ball-side end 321 of the first shaft 32 with respect to the direction parallel to the central axis CL of the ball stud 3 in the steering neutral and leaning neutral position. Further, the open end part 210 is formed in such a manner that the ball-side end 321 of the first shaft 32 is positioned between either of the first inner edge part 211 or the second inner edge part 212 and either of the third inner edge part 213 or the fourth inner edge part 214 with respect to the direction parallel to the central axis CL of the ball stud 3 in the steering neutral and leaning neutral position.

[0058] The open end part 210 is formed in such a manner that the first inner edge part 211 and the second inner edge part 212 allow the tilt angle θw of the ball stud 3 to be variable within the range of ±25 degrees from the position in the steering neutral and leaning neutral position.

[0059] In the leaning vehicle 5, the ball joint 1 is arranged in such a manner that the tilt angle θw of the ball stud 3, which is variable between the first inner edge part 211 and the second inner edge part 212, corresponds to the steering angle of the two front wheels 51F. Thereby, the steering angle range during leaning of the two front wheels 51F can be expanded.

[0060] Specifically, when the two front wheels 51F are steered from their respective steering neutral and leaning neutral positions, the tilt angle θw of the ball stud 3 varies between the first inner edge part 211 and the second inner edge part 212. The first inner edge part 211 and the second inner edge part 212 are formed at positions outward from the circumference of the maximum width part of the ball part 31, and accordingly, the variable range of the tilt angle θw of the ball stud 3, which is limited by the first inner edge part 211 and the second inner edge part 212, is not restricted so strictly. As a result, a large tilt angle θw of the ball stud 3 can be obtained. Even while the two front wheels 51F are leaning, since the tilt angle θw of the ball stud 3 is variable between the first inner edge part 211 and the second inner edge part 212, the tilt angle range of the ball stud 3 becomes large. Thus, the steering angle range during leaning of the two front wheels 51F can be expanded.

[0061] In the leaning vehicle 5, the ball joint 1 is used as the joint mechanism. Therefore, the ball part 31 of the ball stud 3 can be supported by the holder 2 in such a manner to be freely rotatable, and the tie rod 555 is allowed to be displaced relative to the pitman arm 554 or the knuckle 556 when the two front wheels 51F are leaned and/or steered. This does not cause an increase in the size of the part around the two front wheels 51F. Additionally, the third inner edge part 213 and the fourth inner edge part 214, which are formed at positions inward from the circumference of the maximum width part of the ball part 31, are positioned between the first inner edge part 211 and the second edge part 212 separately, and the third inner edge part 213 and the fourth inner edge part 214 function as a stopper that stops the ball stud 3 from being pulled out of the holder 2. This eliminates the need to increase the size of the ball part 31. Therefore, the part around the two front wheels 51F is not increased in size.

[0062] The reason why the ball stud 3 is required to be hard to come off from the holder 2 is as follows: in a case in which the ball joint 1 is used as a joint mechanism that connects a tie rod 555 with a pitman arm 554 or a knuckle 556, when a disturbance is applied to the front wheels 51F or the steering handlebar 551 during steering of the two front wheels 51F, the connection part between the tie rod 555 and the pitman arm 553 or between the tie rod 555 and the knuckle 556 needs a certain level of strength against a force of pulling out the ball stud 3. Even when the leaning vehicle 5 includes a steering mechanism that does not provide a mechanical connection between the steering handlebar 551 and the two front wheels 51F, that is, even when a steering actuator operates to steer the two front wheels 51F in accordance with manipulation applied to the steering handlebar 551, the ball joint 1 is required to have a specific level of strength against a force of pulling out the ball stud 3 so that the steering actuator can continuously control the steering angle against the disturbance inputted to the two front wheels 51F.

[0063] With reference to FIG. 3, the ball joint 1 will be described in more detail. FIG. 3(a) shows the ball joint 1. FIGS. 3(b) and 3(c) show ball joints 100 and 101, respectively, which have structures of comparative examples. In FIGS. 3(b) and 3(c), the left half and the right half of the drawing show different sections of the ball joint 100 or 101. Specifically, the left half of the drawing shows a sectional view of the ball joint 100 or 101 on a plane rotated by 90 degrees around the central axis of the ball stud 300 or 301 from the plane of the sectional view shown in the right half of the drawing. The following descriptions of the ball joints 100 and 101 shown in FIGS. 3(b) and 3(c) are about hypothetical cases in which these ball joints 100 and 101 are used in a leaning vehicle. However, the descriptions do not show that the ball joints 100 and 101 shown in FIGS. 3(b) and 3(c) are usable in a leaning vehicle.

[0064] In the ball joint 100, the body of the holder 200 has an open end part 210A, and the open end part 210A includes two inner edge parts 21A and two inner edge parts 21B. The two inner edge parts 21B are separately positioned between the two inner edge parts 21A. In other words, the two inner edge parts 21A and the two inner edge parts 21B are arranged alternately along the circumference of the open end part 210A. In the ball joint 101, the body of the holder 201 has an open end part 210B, and the open end part 210B has an inner edge 21C on the entire circumference. The inner edge parts 21A and the inner edge parts 12B are formed at positions inward from the circumference of the maximum width part of the ball part 310, with respect to directions perpendicular to the central axis CL1 of the ball stud 300 in the steering neutral and leaning neutral position. As compared with the inner edge parts 21A, the inner edge parts 21B are positioned more inward from the circumference of the maximum width part of the ball part 310, with respect to the directions perpendicular to the central axis CL1 of the ball stud 300 in the steering neutral and leaning neutral position. Thus, all the inner edge parts 21A and the inner edge parts 21B function as a stopper that stops the ball stud 300 from being pulled out of the holder 200. Therefore, the ball stud 300 is inserted upward in FIG. 3(a) into the body of the holder 200 through another open end part (a second open end part). After the ball stud 300 is inserted in the body of the holder 200, a cap 240 is attached to the body of the holder 200 in such a manner as to cover the second open end part of the body of the holder 200. The cap 240 functions as a stopper that stops the ball stud 300 from being pushed into the holder 200 any further.

[0065] In the ball joint 100, even the inner edge parts 21A, which are positioned outward from the inner edge parts 21B with respect to the directions perpendicular to the central axis CL of the ball stud 300 in the steering neutral and leaning neutral position, are positioned inward from the circumference of the maximum width part of the ball part 310 with respect to the direction perpendicular to the central axis CL1 of the ball stud 300 in the steering neutral and leaning neutral position. Accordingly, as compared with the ball joint 1, the tilt angle range of the ball stud 300 is smaller. Therefore, when the ball joint 100 is used in a leaning vehicle, it is difficult to expand the steering angle range during leaning of two front wheels. In order to clearly illustrate the difference between the tilt angle range of the ball stud 3 and the tilt angle range of the ball stud 300, in FIG. 3, the positions of the ball studs 3 and 300 tilted at their respective maximum tilt angles are shown by phantom lines. However, when the ball joints 1 and 100 are practically used, stoppers are attached so as to limit the tilt angles of the ball studs 3 and 300 to smaller angles than their respective maximum tilt angles. Even if such stoppers are attached, it makes no difference as to the fact that the tilt angle range of the ball stud 3 of the ball joint 1 is greater than the tilt angle range of the ball stud 300 of the ball joint 100.

[0066] In the ball joint 101, a cap 242 functions as a stopper that stops the ball stud 301 from being pushed into the holder 201 any further. However, the ball stud 301 is inserted downward in FIG. 3(c) into the holder 201 at the time of assembly of the ball joint 101, and the ball joint 101 lacks in the strength against a force of pulling the ball stud 301 out of the holder 201. Specifically, in assembling the ball joint 101, the ball stud 301 is inserted in the holder 201 through the open end part 210B of the holder 201, which means that the ball stud 301 passes through the open end part 210B, and accordingly, the ball joint 101 lacks in the strength against a force of pulling the ball stud 301 out of the holder 201. Therefore, it is difficult to use the ball joint 100 in a leaning vehicle.

[0067] [Modification of Support Mechanism]

[0068] With reference to FIG. 4, a modification of the support mechanism 52 will be described. In a support mechanism 52A according to the modification, the ball joint 1 is positioned in such a manner that the rotation angle θr of the ball stud 3 corresponds to the steering angle of the two front wheels 51F (not shown in FIG. 4) compared to the support mechanism 52. The rotation angle θr of the ball stud 3 means the rotation angle of the ball stud 3 around the central axis CL. In this modification also, the steering angle range during leaning of the two front wheels 51F can be expanded.

[0069] Specifically, the ball part 31 of the ball stud 3 is supported by the holder 2 to be freely rotatable, and therefore, when the two front wheels 51F are steered from their respective steering neutral and leaning neutral positions, the ball stud 3 rotates around the central axis CL. Thus, the variable range of the rotation angle θr of the ball stud 3 is large. Even while the two front wheels 51F are leaning, the variable range of the rotation angle θr of the ball stud 3 is large. Accordingly, the steering angle range during leaning of the two front wheels 51F can be expanded.

OTHER EMBODIMENTS

[0070] The embodiments and modifications described herein and/or illustrated by the drawings are to make the present teaching easier to understand and not to limit the concept of the present teaching. It is possible to adapt or alter the embodiments and modifications described above without departing from the gist thereof. The gist includes all equivalent elements, modifications, omissions, combinations (for example, combinations of features of the embodiments and modifications), adaptations and alterations as would be appreciated by those in the art based on the embodiments and modifications disclosed herein. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to the embodiments described in the present specification or during the prosecution of the present application. Such embodiments and modifications are to be understood as non-exclusive. For example, the terms “preferable” and “good” in the present specification are to be understood as non-exclusive, and these terms mean “preferable but not limited to this” and “good but not limited to this”, respectively.

REFERENCE SIGNS LIST

[0071] 1: ball joint [0072] 2: holder [0073] 3: ball stud [0074] 5: leaning vehicle [0075] 21: body [0076] 31: ball part [0077] 32: first shaft [0078] 51F: two front wheels [0079] 52: support mechanism [0080] 54: vehicle body [0081] 210: open end part [0082] 211: first inner edge part [0083] 212: second inner edge part [0084] 213: third inner edge part [0085] 214: fourth inner edge part [0086] 554: pitman arm [0087] 555: tie rod [0088] 556: knuckle [0089] θr: rotation angle [0090] θw: tilt angle