JP2007176387A - Front wheel steering device of motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front wheel steering device of a motorcycle capable of reducing the weight and the height of the center of gravity of a vehicle body, hardly causing a diving phenomenon, and reducing restraints on a portion for arranging a steering mechanism. <P>SOLUTION: In this front wheel steering device of a motorcycle, an axle holder 4 is supported by a swing arm 3 comprising lower arms 3b journalled on both sides of a front end of a main frame 2 on its rear end and mounted to the axle holder 4 on its front end, approximately S-shaped upper arms 3a provided almost in parallel to the lower arms 3b, and reinforcing arms 3c connecting the lower arms 3b and the upper arms 3a at one part. A shaft 9b having a steering handle 9a at the top is installed at the center in the width direction at the rear part of the main frame 2 rotatably relative to an approximately vertical shaft, and an arm 23 almost vertically hung at the bottom end of the shaft 9b is connected with a lever 6 extending sideward of the axle holder by a transmission means 24 comprising rods 7a, 7b and linking members 8a, 8b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a device for steering a front wheel of a motorcycle, and more particularly to a front wheel steering device for a motorcycle in which an axle is cantilevered by a swing arm extending forward from a vehicle body.

In general, a telescopic front fork is often used as a device for steering the front wheels of a motorcycle. This is a structure in which a suspension mechanism is incorporated in a steering fork having the same form as a bicycle, and has advantages such as simplicity of structure, mass productivity, and durability compared to other systems. However, since the rigidity with respect to the braking force at the time of braking is insufficient, the fork is bent when the brake is applied, and the slidability of the telescopic structure may be deteriorated. Further, since the suspension mechanism contracts due to the braking force at the time of braking, a so-called diving phenomenon occurs in which the vehicle body turns forward when the brake is applied during high speed traveling. Therefore, there is a problem that the traveling state is likely to become unstable particularly during corner traveling that requires rapid deceleration.
In order to cope with such a problem, a so-called hub center steering type steering device is known in which the axle is cantilevered by a swing arm whose rear end is attached to a vehicle body so as to be swingable in the vertical direction. This method can increase the rigidity with respect to the braking force at the time of braking, and is excellent in maintainability because the tire can be easily replaced. Conventionally, several inventions and devices have been disclosed for the hub center steering system.

  For example, in Patent Document 1, the front end of a swing arm and a knuckle are connected via a joint under the name of “a motorcycle front wheel suspension device”, and the movement of the swing arm in the vertical direction and the rotation direction of the knuckle are not limited. An invention related to a front wheel suspension device for a motorcycle configured as described above is disclosed.

Hereinafter, the invention disclosed in Patent Document 1 will be described with reference to FIG.
FIG. 6 is a perspective view of a front wheel suspension device for a motorcycle according to the prior art.
As shown in FIG. 6, the front wheel suspension device for a motorcycle according to the prior art is such that the lower end portion of the steering stem 54 inserted through the steering pivot 53 is armed via the universal joint 56, the steering rod 57 and the joint 59. 60, and the arm 60 is pivotally attached to a lever 61 protruding laterally from the steering plate 52 via a steering rod 58. A handle 55 is fixed to the upper portion of the steering pivot 53, and the steering pivot 53 and the arm 60 are each installed on a vehicle body (not shown). A joint 62 comprising a first support portion 62a and a second support portion 62b is attached to the upper end of the steering plate 52 that serves as a knuckle, and the rear end of the swing arm 51 is attached to the vehicle body (not shown). The front end of the steering plate 52 is pivotally supported by the first support portion 62a so as to be rotatable on the rotation center in the vehicle width direction, and the steering plate 52 is rotatable on the rotation center substantially orthogonal to the vehicle width direction by the second support portion 62b. It is supported by. Further, the lower end of the steering plate 52 is pivotally supported via a joint (not shown) similar to the joint 62 at the front end of a swing arm (not shown) whose rear end is pivotally supported by a vehicle body (not shown). ing.
In the “front wheel suspension device for a motorcycle” having the above structure, when the handle 55 is rotated, the driving force is transmitted to the steering plate 52 via the steering stem 54 and the steering rods 57 and 58, and the second support portion 62b is moved. As a center, the steering plate 52 rotates in the directions of arrows E and F. Further, when the vehicle body swings in the vertical direction due to road surface unevenness or the like during traveling, the swing arm 51 rotates in the directions of arrows C and D around the end portion supported by the second support portion 62a. That is, when the front wheels are steered, it is difficult to limit the movement of the swing arm in the vertical direction and the knuckle rotation direction.

Further, Patent Document 2 discloses an invention relating to a hub center steer having a structure in which the above-described problem of the telescopic front fork is solved and the number of steering rods is reduced under the name “hub center steer”.
In the invention disclosed in Patent Document 2, a steering rear arm is attached to a lower end of a connection shaft having a steering main arm connected to an upper end so as to be substantially parallel to the steering main arm, and an axle is held at a lower portion. A steering hub carrier arm is attached to the upper part of the hub carrier so as to be substantially parallel to the steering rear arm. The center portion of the steering hub carrier arm is pivotally supported by the high upper arm around the front wheel so as to be rotatable about the vertical axis, and both ends of the steering hub carrier arm are respectively steered to both ends of the steering rear arm. It is connected through a rod.
In the “hub center steer” having the above structure, when the steering main arm is steered, the rotation is transmitted to the steering hub carrier via the connection shaft, the steering rear arm, the steering rod, and the steering hub carrier arm. The front wheels are steered. As described above, since the suspension mechanism of the structure that contracts by the braking force at the time of braking is not incorporated in the steering mechanism of the front wheels, the telescopic front fork described above is similar to the invention disclosed in Patent Document 1. The problem can be solved. In addition, since the number of steering rods is small, steering is not unstable.

Patent Document 3 discloses a front wheel of a motorcycle that can prevent vibration of a knuckle in a front wheel suspension device having a name of “front wheel suspension device of a motorcycle” and having a structure in which a knuckle is steerably supported by a front end of a swing arm. An invention relating to a suspension device is disclosed.
The invention disclosed in Patent Document 3 includes a substantially Y-shaped swing arm in which a rear end is pivotally supported by a vehicle body so as to be swingable in the vertical direction and an upper mounting portion and a lower mounting portion are formed at the front end, and a front wheel A knuckle supported at both ends by the upper and lower mounting parts at the top and bottom of the axle, a crank formed on the upper part of the knuckle, and one end pivotally connected to this crank via a universal joint and arranged above the front wheel And a torque rod that moves back and forth in conjunction with the handle.
In the “motorcycle front wheel suspension device” having the above-described structure, the swing arm supports the knuckle in a two-sided manner above and below the axle of the front wheel, so that vibration of the knuckle is prevented.

Japanese Patent Laid-Open No. 7-2158 JP-A-6-99872 JP-A 63-207781

  However, in the invention disclosed in Patent Document 1 which is the above-described prior art, the second support portions 62b serving as the center of rotation when steering the front wheels are respectively attached to the upper and lower sides of the steering plate 52 with the axle interposed therebetween. Since the lever 61 used for steering the steering plate 52 is disposed between the two second support portions 62b, when the steering plate 52 swings in the vertical direction, the steering plate 52 moves in the E and F directions. There is a problem that the resistance to rotation of the motor increases and the maneuverability decreases.

  Further, in the invention disclosed in Patent Document 2, since the steering mechanism is disposed above the front wheels, there is a problem that the center of gravity of the vehicle body is increased and stability during traveling is lowered.

  Furthermore, in the invention disclosed in Patent Document 3, since the steering shaft of the front wheel does not pass through the center of the front wheel, there is a problem that the turning radius of the vehicle body is increased and the resistance during front wheel operation is increased. Further, since a steering mechanism such as a steering wheel is disposed above the front wheel, the same problem as that of the invention disclosed in Patent Document 2 is caused.

  The present invention has been made in response to such a conventional situation, and can reduce the weight and the center of gravity of a vehicle body, hardly cause a diving phenomenon, and has few restrictions on the location of a steering mechanism. An object is to provide a steering device.

In order to achieve the above object, a front wheel steering device for a motorcycle according to claim 1 is a front wheel steering device for a motorcycle that is steered while being supported only from one side of the left and right side surfaces of the front wheel of the motorcycle. A swing arm installed on the main frame of the two-wheeled vehicle and extending to one of the left and right side surfaces of the front wheel, a steering shaft provided at the end of the swing arm, and a front wheel via a hub orthogonal to the steering shaft An axle holder that is rotatably provided on the steering shaft, and that extends to the side of the axle holder, and receives the driving force to rotate the axle holder at a desired angle. And a lever for steering the front wheels.
In the front wheel steering device for a motorcycle having such a structure, the swing arm acts to restrain movement of the steering shaft in the vehicle width direction. Further, since the steering shaft is arranged so as to pass through the center of the axle as viewed from the side of the front wheel, the turning radius of the vehicle body is reduced and the resistance when steering the front wheel is reduced. In addition, the axle holder has a simple structure.

According to a second aspect of the present invention, in the front wheel steering apparatus for a motorcycle according to the first aspect, the hub is provided rotatably on the axle, the brake disc plate is provided around the hub, and the axle holder is provided. A disc caliper that can clamp both sides of the brake disc plate, the brake disc plate is arranged at the center in the width direction of the front wheel, and the disc caliper clamps both sides of the brake disc plate to brake the rotation of the front wheel It is what.
In the front wheel steering device for a motorcycle having such a structure, the braking force during braking acts equally to the left and right in the width direction of the front wheel. That is, there is no difference due to the rotation direction of the front wheels with respect to the braking force during braking.

According to a third aspect of the present invention, in the front wheel steering apparatus for a motorcycle according to the first or second aspect, a shaft provided at the center in the width direction of the main frame so as to be rotatable with respect to the vertical axis, and an upper portion of the shaft. A steering handle attached to the shaft, an arm substantially suspended from the lower end of the shaft, and a transmission means for transmitting the driving force generated by the steering handle to the lever.
In the front wheel steering device for a motorcycle having such a structure, it is not necessary to dispose the steering handle in the vicinity of the front wheel. That is, there are few restrictions regarding the arrangement of the steering wheel.

According to a fourth aspect of the present invention, in the front wheel steering apparatus for a motorcycle according to the third aspect, the transmission means includes a rod whose end is pivotally attached to a lever or an arm, and the rod and the lever or the arm are ball joints. It is characterized by being connected by.
In the front wheel steering device for a motorcycle having such a structure, the front wheel swings up and down due to the influence of unevenness on the road surface and the relative positional relationship between the rod and lever or the rod and arm changes. Even if the change amount is within a predetermined range, the operation of the rod, lever or arm is not hindered.

  As described above, in the front wheel steering device for a motorcycle according to claim 1 of the present invention, the steering shaft does not sway from side to side during traveling, so that steering is stable. Further, since the axle holder has a simple structure, it is possible to easily remove the front wheels when exchanging tires for maintenance or the like, and it is possible to reduce the size and weight of the steering device. Further, the axle holder can be rotated with a small force without difficulty by the steering of the lever, and the steering radius is small, so that the steering is easy.

  According to the front wheel steering apparatus for a motorcycle according to claim 2 of the present invention, a stable traveling posture can be maintained, which is safe.

  In the front wheel steering apparatus for a motorcycle according to claim 3 of the present invention, for example, the center of gravity of the vehicle body can be lowered by arranging the steering handle at a low position. Thereby, the safety | security at the time of driving | running | working can be improved.

  In the front wheel steering device for a motorcycle according to claim 4 of the present invention, it is possible to maintain a stable traveling state even when the road surface is bad.

  Examples of a front wheel steering apparatus for a motorcycle according to the best mode for carrying out the invention will be described below with reference to FIGS.

FIGS. 1 and 2 are an external perspective view and a partial plan view, respectively, of an example of a front wheel steering device for a motorcycle according to an embodiment of the present invention.
As shown in FIGS. 1 and 2, the front wheel steering device 1 of the present embodiment is a so-called hub center steering type steering device in which a front wheel 5 of a motorcycle is supported from the side by a swing arm 3, and the front wheel 5 is attached. The front wheel 5 is steered by directly operating the axle holder 4.
The swing arm 3 includes an upper arm 3a, a lower arm 3b, and a reinforcing arm 3c. The lower arm 3b has two rear ends that are bifurcated on both sides of the front end of the main frame 2 and are horizontally supported so as to be vertically movable, and a front end that extends to one side surface of the front wheel 5 is attached to the axle holder 4. It has been installed. The substantially S-shaped upper arm 3a disposed substantially parallel to the lower arm 3b is supported by a rear end that is horizontally supported on one side of the front end of the main frame 2 so as to move up and down, and forwards so as to bypass the front wheel 5. The extended front end is attached to the axle holder 4 together with the front end of the lower arm 3b. The lower arm 3b and the upper arm 3a disposed above the lower arm 3b are partially connected by a reinforcing arm 3c. That is, the swing arm 3 can swing up and down about the rear end. A shock absorber 11 is disposed between the vicinity of the rear end of the upper arm 3a and the main frame 2 to mitigate an impact generated in the vertical direction by the operation of the swing arm 3.
A post 10a is installed at the center of the rear of the main frame 2 in the vehicle width direction, and a shaft 9b with a steering handle 9a attached to the top is inserted into the post 10a so as to be rotatable about a substantially vertical axis. The arm 23, the lever 6, the rods 7a and 7b, and the link members 8a and 8b for transmitting the rotational driving force of the steering handle 9a to the front wheels 5 will be described later.

  In the front wheel steering device 1 for a motorcycle having such a structure, the translational movement of the front wheel 5 in the vehicle width direction is restricted by the swing arm 3. In addition, since the shock absorber 11 is installed only on one side, there is no problem in traveling due to a deviation in the characteristics of the left and right forks seen in the telescopic front fork.

  In FIGS. 1 and 2, the swing arm 3 supports the front wheel 5 from the right side when viewed in the traveling direction. However, the present invention is not limited to this, and the swing arm 3 and the shock absorber 11 are attached to the left and right sides. It is good also as a structure which supports the front wheel 5 from the left side. Further, the position and the number of the reinforcing arms 3c that connect the upper arm 3a and the lower arm 3b are not limited to those shown in FIG. 1, but can be appropriately changed by providing a plurality of reinforcing arms 3c on the front wheel 5 side or the main frame 2 front end side. It is. If the upper arm 3a and the lower arm 3b are high in rigidity and need not be reinforced, a structure in which the reinforcing arm 3c is not attached may be employed. Furthermore, when only the lower arm 3b is sufficiently rigid, the shock absorber 11 may be attached to the lower arm 3b and the upper arm 3a may be omitted. The upper arm 3a, whose rear end is pivotally supported on one side of the front end of the main frame 2 and whose front end is mounted on the axle holder 4, may be any shape as long as it bypasses the front wheel 5 and extends forward. In particular, it is not limited to a substantially S shape, and various modifications are possible.

Next, the structure of the axle holder 4 will be described with reference to FIGS.
3 is a cross-sectional view taken along line KK in FIG. 2, and FIG. 4 is a cross-sectional view taken along line LL in FIG. In addition, the same code | symbol is attached | subjected about the same component as shown in FIG.1 and FIG.2, and the description is abbreviate | omitted.
As shown in FIGS. 3 and 4, the hub 14 is rotatably attached to the axle 15 protruding from the side surface of the axle holder 4 using bearings 18 a and 18 a and a nut 21 c, and the wheel 13 of the front wheel 5 is connected to the hub 14. Are fixed using bolts 20a and nuts 21a. The king pin 19 serving as a steering shaft inserted into the bearings 18b and 18b and the collar 22b press-fitted into the front end of the swing arm 3 has both ends thereof on the upper and lower surfaces of the axle holder 4 by nuts 21d and 21d and the collars 22a and 22a. Each is fixed and orthogonal to the axle 15. The king pin 19 is disposed at the center in the width direction of the front wheel 5 and is disposed so as to pass through the center of the axle 15 when viewed from the side surface of the front wheel 5. A lever 6 extends laterally from the lower surface of the axle holder 4, and the front end of the rod 7a is connected to the end of the lever 6 via a ball joint 12a. In other words, when the rod 7a is moved back and forth, the axle holder 4 rotates around the steering shaft.
A brake disc plate 16 is attached to the hub 14 so as to be positioned at the center of the front wheel 5 in the width direction, and the axle holder 4 holds both sides of the brake disc plate 16 so as to brake the rotation of the front wheel 5. A disc caliper 17 is attached using bolts 20b and nuts 21b.

  In the axle holder 4 having the above structure, since the king pin 19 is disposed at the center of the front wheel 5 in the width direction, the front wheel 5 is steered left and right with respect to the center of the vehicle width. That is, since the distance between the front and rear axles does not change even if the front wheel 5 is steered to the left or right side, the steering is stabilized. In addition, since the king pin 19 is disposed so as to pass through the center of the axle 15 when viewed from the side of the front wheel 5, the turning radius of the vehicle body is reduced and the resistance to rotation of the front wheel 5 is reduced. Furthermore, the structure of the axle holder 4 is simplified. Further, since the brake disc plate 16 is disposed at the center in the width direction of the front wheel 5, the braking force by the brake acts on the front wheel 5 equally on the left and right. In other words, even if the front wheel 5 is rotated to the left or right, there is no difference in the braking force by the brake, so that the steering is stabilized.

  3 and 4, the arm 6 extends from the lower surface of the axle holder 4. However, the present invention is not limited to this, and may be configured to extend from a part of the axle holder 4 other than the lower surface. . Further, the shape of the axle holder 4 is not limited to a substantially box shape, and can be variously modified. For example, a substantially U-shaped structure in a side view, which includes only an upper surface and a lower surface to which the king pin 19 is attached and a side surface from which the axle 15 projects, may be employed.

The transmission means 24 for connecting the arm 23 at the lower end of the shaft 9b and the lever 6 will be described with reference to FIG.
FIG. 5 is a schematic diagram showing the configuration of the transmission means 24. The same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof is omitted.
As shown in FIG. 5, the rear end of the rod 7b is connected to the end of the arm 23 at the lower end of the shaft 9b via a ball joint 12d, and the front end of the rod 7b is connected to one end of the link member 8a via the ball joint 12c. It is connected. The other end of the link member 8a is connected to one end of the link member 8b via a link shaft (not shown) inserted into the post 10b, and the other end of the link member 8b is connected to the ball joint 12b via a ball joint 12b. The rear end of the rod 7a is connected, and the front end of the rod 7a is connected to the end of the lever 6 via the ball joint 12a. Further, the axle holder 4 is disposed so that a steering rotation shaft 25 coinciding with the king pin 19 shown in FIG. 3 or 4 is inclined with respect to the vertical direction 26 so as to form a desired caster angle 27.
In the front wheel steering apparatus 1 having the above structure, the transmission means 24 transmits the rotational driving force generated by the steering handle 9 a to the lever 6. In addition, when the front wheel 5 swings in the vertical direction due to the unevenness of the road surface, the vertical position is displaced between the rod 7a and the lever 6 or the link member 8b, or between the rod 7b and the arm 23 or the link member 8a. There is. The ball joints 12a to 12d act so as to absorb such a shift and not hinder the operation of the rods 7a and 7b, the lever 6 or the arm 23.

  In FIG. 5, the rods 7a and 7b are connected by the link members 8a and 8b. However, the arm 23 and the lever 6 may be connected only by the rod 7a, and the link members 8a and 8b may not be used. Moreover, you may use the universal joint with a some rotating shaft instead of the ball joints 12a-12d. Furthermore, instead of the transmission means 24 constituted by the rods 7a and 7b and the link members 8a and 8b, a structure may be adopted in which the rotational driving force of the arm 23 is transmitted to the lever 6 by a hydraulic mechanism.

  As described above, according to the front wheel steering device for a motorcycle of the present embodiment, the axle holder 4 has a simple structure, so that the tire can be easily replaced and maintained. Moreover, since there are few restrictions with respect to arrangement | positioning of the steering handle 9a, it is possible to aim at the low center of gravity of the whole vehicle body, for example by arrange | positioning the steering handle 9a in a low position. Furthermore, since the steering mechanism of the front wheels 5 is simple, the weight of the vehicle body can be reduced. Therefore, the manufacturing cost can be reduced. In addition, the steering shaft does not sway from side to side during traveling, the steering is stabilized, and braking by the brake is reliably performed, so the steering stability performance is good.

  The inventions described in claims 1 to 4 can be applied not only to a motorcycle but also to a device for steering a front wheel of a motorcycle or a bicycle.

1 is an external perspective view of an example of a front wheel steering device for a motorcycle according to an embodiment of the present invention. 1 is a partial plan view of an example of a front wheel steering device for a motorcycle according to an embodiment of the present invention. FIG. 3 is a sectional view taken along line KK in FIG. 2. FIG. 4 is a cross-sectional view taken along line LL in FIG. 3. It is a schematic diagram which shows the structure of a transmission means. FIG. 6 is a perspective view of a front wheel suspension device for a motorcycle according to the prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Front wheel steering device 2 ... Main frame 3 ... Swing arm 3a ... Upper arm 3b ... Lower arm 3c ... Reinforcement arm 4 ... Axle holder 5 ... Front wheel 6 ... Lever 7a, 7b ... Rod 8a, 8b ... Link member 9a ... Steering handle 9b ... shafts 10a, 10b ... posts 11 ... shock absorbers 12a-12d ... ball joints 13 ... wheels 14 ... hubs 15 ... axes 16 ... brake disc plates 17 ... disc calipers 18a, 18b ... bearings 19 ... king pins 20a, 20b ... bolts 21a- 21d ... Nuts 22a, 22b ... Collar 23 ... Arm 24 ... Transmission means 25 ... Steering rotation shaft 26 ... Vertical direction 27 ... Caster angle 51 ... Swing arm 52 ... Knuckle 53 ... Steering pivot 54 ... Stearin Stem 55 ... handle 56 ... universal joint 57, 58 ... steering rod 59 ... Joint 60 ... arm 61 ... lever 62 ... fitting 62a ... first support portion 62b ... second supporting portion

Claims (4)

  A front wheel steering device for a motorcycle that steers while supporting only from one side of the left and right side surfaces of a front wheel of a motorcycle, and is installed on a main frame of the motorcycle and extends to one of the left and right sides of the front wheel. A swing arm, a steering shaft provided at an end of the swing arm, and an axle that is orthogonal to the steering shaft and rotatably supports the front wheel via a hub, and is rotatable about the steering shaft. A motorcycle comprising: an axle holder provided; and a lever that extends to a side of the axle holder and that steers the front wheel by receiving a driving force and rotating the axle holder by a desired angle. Front wheel steering device.   A hub provided rotatably on the axle; a brake disc plate provided around the hub; and a disc caliper provided on the axle holder and capable of sandwiching both surfaces of the brake disc plate; 2. The front wheel steering device for a motorcycle according to claim 1, wherein the front wheel steering device is disposed at a center in a width direction of the front wheel, and the disc caliper clamps both surfaces of the brake disc plate to brake rotation of the front wheel.   Generated by a shaft provided at the center in the width direction of the main frame so as to be rotatable with respect to a vertical axis, a steering handle attached to an upper portion of the shaft, an arm substantially suspended from the lower end of the shaft, and a steering handle The front wheel steering apparatus for a motorcycle according to claim 1 or 2, further comprising a transmission means for transmitting the driving force to the lever. The motorcycle according to claim 3, wherein the transmission means includes a rod whose end is pivotally attached to the lever or the arm, and the rod and the lever or the arm are connected by a ball joint. Front wheel steering device.