JPH01309886A - Steering gear of motorcycle - Google Patents

Abstract

PURPOSE:To decrease occurrence of shimmy effectively, by attaching a dynamic damper which absorbs vibration in the rotating peripheral direction of a front fork to a steering member which steers together with a steering wheel. CONSTITUTION:A dynamic damper 9 is installed at the front end of a front fender which is steered together with a front steering wheel. The sliding axle 11 of the dynamic damper 9 is directed in the rectangular direction to the running direction and is fixed in the dent of the front end of the front fender. As the weight 12 of the dynamic damper 9 is supported by a front fork through the front fender, the weight 12 becomes movable elastically by a coil spring 13 in a rectangular face to a steering axle. Therefore, vibration of the front fork in the rotating peripheral direction with the steering axle as an axle is absorbed. Energizing power of the spring 13 is set by adjustment of a nut 15 to a frequency where for its natural frequency shimmy is easy to occur, and thus the occurrence of the shimmy is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steering system for a motorcycle, and more particularly to a steering system for a motorcycle that reduces the effects of shimmy.

[Prior Art] In a conventional motorcycle steering system, a front fork is rotatably supported on the vehicle body via a steering shaft, and the front fork is rotated by a handle to steer the front wheel. In a motorcycle equipped with such a steering device, so-called shimmy may occur during driving.

This shimmy is a phenomenon in which the steering wheel vibrates in the circumferential direction of its rotation around the steering shaft due to various factors during driving, and motorcycle manufacturers try to avoid this phenomenon called shimmy. A great deal of time and effort has been spent on steering systems at each stage of design, development, and manufacturing.

However, many of the causes of shimmy have not yet been elucidated, and at present they can only be avoided through empirical testing.

However, manufacturers are making every effort to ensure that motorcycle steering systems are perfect in order to avoid shimmy caused by various factors.

[Problems to be Solved by the Invention] However, when motorcycles are put on the market and reach the end users, even the best-adjusted and designed steering devices may experience shimmy.

Despite manufacturers' efforts to avoid this situation, the factors involved in the shimmy phenomenon remain unclear.
Furthermore, various factors caused by the rider cause the steering wheel of a motorcycle to shimmy.

In this way, shimmy is thought to be caused by various factors after the motorcycle reaches the consumer, such as the riding style of the individual rider, modification of the motorcycle, replacement of parts, and other factors that cannot be predicted by the manufacturer. It is being said.

For this reason, even in motorcycles that have been optimally adjusted at the factory to prevent shimmy of any kind, shimmy may occur due to various factors that the manufacturer cannot predict.

This invention was made in view of the above circumstances, and an object of the present invention is to provide a steering device for a motorcycle that reduces the effects of shimmy occurring in a motorcycle due to various environments or unpredictable usage. .

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a motorcycle in which a front fork is rotatably supported on the vehicle body via a steering shaft, and a steering wheel is steered by the front fork. The present invention is characterized in that a dynamic damper is attached to the steering member that steers together with the steering wheel, which absorbs vibrations in the circumferential direction of rotation of the front fork.

[Function] In this invention, when shimmy occurs in the steering wheel while driving,
Vibration in the circumferential direction of rotation of the front fork due to this shimmy is absorbed by the dynamic damper, reducing the impact of the shimmy on driving.

[Example] Next, an example of the present invention will be described in detail with reference to the accompanying drawings.

1 to 4 are diagrams showing a first embodiment of a steering system for a motorcycle to which the present invention is applied. Reference numeral 1 in the figure indicates a front fork, which is composed of an inner tube 2 and an outer tube 3. The inner tube 2 is rotatably supported by a head vibrator 4 of a motorcycle body via a steering shaft 5, and a handle 6 for steering the inner tube 2 is supported at the upper end of the inner tube 2.

The outer tube 3 is telescopically supported by the inner tube 2, and a front wheel 7, which is a steering wheel, is pivotally supported at the lower end of the actor tube 3. A front fender 8 that covers the upper part of the front wheel 7 is supported on the outer tube 3, and a dynamic damper 9 is provided at the tip of the front fender 8, which is a steering member.

The dynamic damper 9 is installed with a stay 10 and a sliding shaft 11
．． Weight! 2. It is composed of a coil spring 13 and the like.

A bracket 14 is fixed perpendicularly to the stay 1o, and the sliding shaft 11 is mounted on the bracket 14 so that the shaft is parallel to the stay 10, and one end 11a of the sliding shaft 11 is supported. A weight 12 is slidably attached to the sliding shaft 11, and coil springs 13 are arranged on the sliding shaft 11 at both ends of the weight 12. Adjustment nut 15 screwed onto the other end 11b
is pressed through the washer 16 by the adjusting nut 1.
By changing the position of the coil spring 13, the biasing force of the coil spring 13 can be adjusted.

The dynamic damper 9 is mounted with the sliding shaft 11 facing perpendicular to the running direction, and the stay lO is fixed to the recess 8a formed at the tip of the front fender 8 with screws 17 through the hole 10a. has been done. A cover 8b is attached to the recess 8a of the front fender 8, and the dynamic damper 9 is housed inside so that it cannot be seen from the outside.

In this way, the weight 12 of the dynamic damper 9 is supported by the front fork 1 via the front fender 8, and therefore, as shown in the basic conceptual diagram of FIG. It is elastically movable with
The vibration of the front fork 1 in the rotational circumferential direction A around the steering shaft 4 is absorbed.

The dynamic damper 9 moves the position of the adjustment nut 15 to adjust the biasing force of the coil spring 13, thereby setting its natural frequency to a frequency at which shimmy is likely to occur during driving. When shimmy occurs in the front wheel 7 while the motorcycle is running, a force is applied to the front fork 1 due to the shimmy to cause it to vibrate in the rotational circumferential direction A, but the dynamic damper 9
absorbs this.

In this way, attach the front fender 8 to the front fork 1.
Since the dynamic damper 9 that absorbs the vibration in the circumferential direction A of rotation of the steering shaft 5 is attached through the dynamic damper 9, the dynamic damper 9 absorbs this vibration, and the 129 caused by shimmy to travel is reduced.

For this reason, the steering system of a motorcycle, which is composed of a #mulberry rudder shaft 5, a front fork 11, a handle 6, a front wheel 7, etc., is shipped from the factory in the best condition, and after it is released on the market, for example, individual This reduces the occurrence of shimmy during riding due to differences in the riding style of riders, the usage environment, modifications to the vehicle body, replacement of parts, etc. that cannot be predicted by the manufacturer, and improves riding comfort. Deterioration is prevented.

In addition, the dynamic damper 9 houses the sliding shaft 11, the weight 12, the coil spring 13, etc. in a casing (not shown), fills it with oil, and attaches the housing to the stay 10.
If it is installed with the oil, the frequency range that resonates with the oil can be widened, making it possible to more effectively reduce the occurrence of shimmy.

FIG. 5 and FIG. 6 are diagrams showing a second embodiment. The dynamic damper 18 of this embodiment is attached to the front fender 1.
9. It is composed of a weight 20 at the tip, a spring 21, etc. That is, the front fender 19 is divided into a front fender 1 (la) and a rear fender 19b.
It is supported via a bearing 23 so as to be rotatable in the left and right direction. In addition, the rear fender 19b has a fork brace 22.
It is fixed at a position below the front fender 19a.

Furthermore, springs 21 are provided between both sides of the base 19c of the front fender 19a and the protrusions 22a at both ends of the fork brace 22 to constantly bias the front fender 19a in the direction of movement.

A weight 20 is supported inside the tip of the front fender 19a,
The 1iilt 20 is elastically movable in a plane perpendicular to a steering axis (not shown).

In addition, in this embodiment, the front fender 19a itself may be used as a weight without providing a special weight to the front fender 19a.Furthermore, the front fender 19 is not divided into front and rear halves, but is integrated and biased by a spring. You can do it like this.

FIG. 7 and FIG. 8 are diagrams showing a third embodiment. In this embodiment, a dynamic damper 24 is attached above an under bracket 25 that connects the left and right inner tubes 2. In this dynamic damper 24, a weight 29 is supported by a support 27 fixed to the inner tube 2 with a bolt 26 via a plate spring 28, and the weight 29 is elastically moved in a direction perpendicular to a steering axis (not shown). It is now possible. Since this dynamic damper 24 is easy to install, it can be used for commercial purposes.

In this embodiment, the plate spring 28 that supports the weight 29 may be made of baked rubber, and the dynamic damper 24 is attached to the outer tube 3, the under bracket 25, and the handle crown in addition to the inner tube 2. 31 etc. may be sufficient.

FIG. 9 and FIG. 10 are diagrams showing a fourth embodiment. The dynamic damper 30 of this embodiment is constructed as follows. That is, the rotating body 32 is supported by the steering shaft 5 of the head vibe 4 on which the handle crown 31 is pivotally supported, and this rotating body 32 has a base portion 32a, an arm portion 32b, and a heel portion 3.
2c is integrally formed. A ring 33 is integrally bonded to the inside of the base 32a with an annular rubber 34, and this ring 33 is fastened to the head vibrator 4 with a nut 36 via a washer 35.

In this embodiment, if the arm portion 32b is formed of a plate spring, there is no need to interpose the annular rubber 34.

FIG. 11 and FIG. 12 are diagrams showing the fifth embodiment. In this embodiment, dynamic dampers 37 are attached to both left and right ends of a front axle 38 supported by the outer tube 3. In this dynamic damper 37, a weight 40 is supported by a leaf spring 39 fixed to the front axle 38, and the weight 40 is elastically movable in the front-rear direction, that is, in a direction substantially perpendicular to the steering axis. In this embodiment, the leaf spring 39 may be made of baked rubber.

FIGS. 13 to 15 are diagrams showing the sixth embodiment. In this embodiment, a dynamic damper 41 is provided at the tip of a front fender 42. A mounting stay 43 of the dynamic damper 41 is supported by the front fender 42 with bolts 44 and nuts 45, and a plate spring 46 is fixed to the mounting stay 43 by welding. Further, a weight 47 is attached to this leaf spring 46, one half 47a of this weight 4 is fixed with a screw 48, and the weight 47a is fixed to this half 47a.
The other half 47b of 7 is fixed with screws 49. Therefore, the weight 47 is elastically movable in the left-right direction, that is, in a direction substantially perpendicular to the steering shaft (not shown).

FIG. 16 and FIG. 17 are diagrams showing the seventh embodiment. The dynamic damper 50 of this embodiment is based on the one of the first embodiment and improved to have an outer diameter sliding type, and is provided at the tip of the front fender 8 similarly to the first embodiment.

The dynamic damper 50 includes a stay 51, a casing 52, a weight 53, coil springs 54a and 54b, and the like. That is, the mounting is done by attaching the pedestal 55 to the stay 51.
A guide tube 56 is fixed to the outer circumference of a weight 53 inserted through the casing 52, and a bearing 57 interposed between a groove 56a of the guide tube 56 and the casing 52 supports the weight 53. 53 can slide smoothly inside the casing 52. Coil springs 54a are provided at both ends of the weight 53.

54b is arranged, and the coil springs 54a, 54b are pressed by the cap 58 screwed onto the casing 52.
is given a biasing force.

The dynamic damper 50 is similar to that of the first embodiment,
For installation, the stay 51 is fixed to a recess 8a formed at the tip of the front fender 8 with screws 17.

Furthermore, when oil is poured into the casing 52 of the dynamic damper 50, the range of frequencies that resonate with the oil can be widened, making it possible to more effectively reduce the occurrence of shimmy.

FIG. 18 is a diagram showing the eighth embodiment. In this embodiment, a dynamic damper 59 is attached to the tip of a front fender 60. This dynamic damper 59 is
A peg 63 is supported on a support 61 fixed to the front fender 60 via an elastic body 62 such as rubber or a leaf spring, and the weight 63 is elastically movable in a direction perpendicular to a steering shaft (not shown). It has become. In this embodiment, the elastic body 62 that supports the weight 63 may be attached to the rear end of the front fender 60.

[Effects of the Invention] As explained above, in this invention, a dynamic damper that absorbs vibrations in the circumferential direction of rotation of the front fork is attached to the steering member that steers the steering wheel together with the steering wheel. When shimmy occurs in the front wheel, the dynamic damper absorbs the vibration caused by this shimmy in the rotational circumferential direction of the front fork, making it possible to effectively reduce the occurrence of shimmy due to various unpredictable usage conditions by the user. .

[Brief explanation of the drawing]

Figures 1 to 3 show the first embodiment, Figure 1 is a plan view of the dynamic damper, Figure 2 is a partial sectional view of the front fender with the dynamic damper attached, and Figure 3 is a side view of the front fork. 4 are basic conceptual diagrams of the steering device of the present invention, FIGS. 5 and 6 show a second embodiment, FIG. 5 is a perspective view of the front fender, FIG. 6 is a bottom view, and FIG. 7 and 8 show the third embodiment, FIG. 7 is a front view of the front fork, and FIG. 8 is a partial sectional view taken along ■-■ in FIG. 7. FIGS. 9 and 10 are the fourth embodiment. Fig. 9 is a front view of the front fork, Fig. 10 is a plan view, Figs. 11 and 12 show the fifth embodiment, Fig. 11 is a side view of the front fork, and Fig. 12 is a front view. A front view of the axle, FIGS. 13 to 15 show the sixth embodiment, FIG. 13 is a side view of the dynamic damper attached to the front fender, and FIG. 14 is a side view with the half-rest of the weight removed. , FIG. 15 is a sectional view taken along line XV-XV in FIG. 14, FIGS. 16 and 17 show the seventh embodiment, FIG. 16 is a plan view of the dynamic damper, and FIG. 17 is a front view with the dynamic damper installed. FIG. 18, which is a partial sectional view of the fender, is a perspective view of the front fender to which the dynamic damper of the eighth embodiment is attached. In the figure, numeral 1 is a front fork, 5 is a steering shaft, 7 is a front wheel, and 9, 18, 24, 30.37.41°50.59 is a dynamic damper. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] In a motorcycle in which a front fork is rotatably supported on the vehicle body via a steering shaft and a steering wheel is steered by the front fork, a steering member that steers together with the steering wheel is configured to rotate the front fork. A motorcycle steering system equipped with a dynamic damper that absorbs vibrations in the circumferential direction.