JPH01156191A - Rear wheel supporter for motorcycle - Google Patents

Abstract

PURPOSE: To steer a rear wheel with lateral force acting on the ground point of a tire by crossing a line segment connecting two points at the upper and lower parts of a knuckle to arm member side with a perpendicular line passing through the ground point of the rear wheel tire, so as to form a caster angle. CONSTITUTION: A line segment K which connects the central points A, B of a ball joint connected by the protrusion part of a knuckle 41 to the knuckle holders 26, 26 of a rear swing arm 21 side is formed so as to cross a vertical line L passing through the ground point of a rear wheel tire when viewed from a side surface, so that a caster angle θ is formed at the rear wheel. Therefore, the line segment K becomes the steering axis of the rear wheel. When it becomes turning driving and lateral force is applied to the ground point, an intersection to the ground surface of the steering axis K is positioned by the angle θ, therefore, it is possible for the rear wheel to conduct steering in the same direction as the turning direction as a result of a moment generated, and improve turning performance.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention utilizes lateral force acting on the tire contact point during cornering, lane changes, etc. in a motorcycle without providing a steering device on the rear wheel side. This invention relates to a rear wheel support device that is capable of steering the rear wheels by rotating the vehicle and preventing the occurrence of wobble during high-speed driving.

(Prior Art) A motorcycle in which one end side of a drive shaft of a rear wheel is supported with respect to a rear fork via an elastic device is known from Japanese Patent Application Laid-open No. 70277/1985, which was proposed by the present applicant. ing. According to this, it is possible to absorb and alleviate the horizontal vibrations of the rear wheels that are experienced during high-speed driving, and it is possible to prevent the occurrence of wobble (high-frequency vibrations around the steering shaft) without affecting the dynamic characteristics of the tires.

Furthermore, a motorcycle equipped with a steering device connected from a bar handle to the rear wheel side is also known from Japanese Patent Laid-Open No. 62-71780, which enables steering of the front and rear wheels and improves turning performance.

(Problems to be Solved by the Invention) Incidentally, the latter requires an interlocking rear wheel steering device in addition to the usual front wheel steering device.

Also, unlike four-wheeled vehicles such as passenger cars, motorcycles use a steering operation by banking the vehicle body to one side when cornering or changing lanes, so only a small amount of steering angle is required for the rear wheels. .

On the other hand, although the former method can prevent the occurrence of bulging, it does not allow the rear wheels to be steered to follow the steering.

Therefore, an object of the present invention is to prevent the occurrence of crashes in motorcycles, and also to prevent cornering by creating a trail by providing a caster angle on the rear wheel without providing a steering device on the rear wheel side. The rear wheels can be steered by using the lateral force that acts on the tire contact point during lane changes, etc., and due to the characteristics of the elastic device, the rear tires and the vehicle body move as one due to high resistance at the beginning. It is an object of the present invention to provide a rear wheel support device which suppresses the generation of cornering force and attenuates the vibration of a vehicle body with a low resistance force against vibrations with an amplitude exceeding that range.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the objects, the present invention provides a rear wheel support device for a motorcycle, including an arm member 21 extending rearward from the vehicle body, and a rotatable arm member 21 extending rearward from the vehicle body. A drive shaft 31 supported by this drive shaft 3
1, the rear wheel hub 38. A knuckle 41 that rotatably supports this rear wheel hub 38 and is bendably connected to the arm member 21 side at two points A and B above and below that pass through the drive shaft center 0, and this knuckle 41 and the arm member 21 side The elastic device 51 is installed, and the line segment K connecting the upper and lower connection points A and B of the knuckle 41 with respect to the arm member 21 side in side view is connected to the vertical line passing through the grounding point S of the rear tire 16t. They intersect to provide a caster angle θ to the rear wheels 16, and also provide a resistance force to regulate the steering behavior of the rear wheels 16, and have elastic properties that provide a high resistance force at the beginning of the steering behavior. elastic device 51
It is characterized by having the following.

(Function) A knuckle 41 bendably connects a rear wheel hub 38 to a drive shaft 31 rotatably supported by an arm member 21 extending rearward from the motorcycle body, and rotatably supports the rear wheel hub 38. The arm member 2 of this knuckle 41 is bendably connected to the arm member 21 side at two upper and lower points A and B passing through the drive shaft center 0.
The rear wheels 16 can be steered by using the line segment connecting the upper and lower connection points A and B with respect to the first side as the steering axis.

Further, an elastic device 5 is provided on the knuckle 41 and the arm member 21 side.
1, the elastic device 51 causes the rear wheel 16 to
It is possible to provide a resistance force against the steering behavior of the vehicle, regulate the amount of steering, and also absorb and alleviate the horizontal vibrations of the rear wheels 16 that are received during high-speed driving, thereby preventing the occurrence of wobble.

Since the rear wheel 16 is provided with a caster angle θ by intersecting the steering axis K with a vertical line passing through the grounding point S of the rear tire 16t in a side view, the rear wheel 16
A trail occurs, and the rear wheels 1 are caused to move around the steering axis due to the lateral force F that acts on the tire contact point S due to the steering operation of the vehicle body during corner links or lane changes.
6 or 6 will be steered.

Moreover, since the elastic device 51 has an elastic property that provides a high resistance force at the initial stage of the steering behavior of the rear wheels 16 due to the lateral force F, the high resistance force initially causes the rear tires 16t and the vehicle body to become integral. When the vibration amplitude exceeds this, the rear tires lag behind the vehicle body by 16 tons due to the low resistance force (the slip angle decreases), which suppresses the generation of cornering force and reduces the vibration of the vehicle body. is also attenuated.

(Example) Examples will be described below based on the accompanying drawings.

FIG. 1 shows a motorcycle as an example to which the present invention is applied, and the illustration shows a body frame 2 on which an engine 1 is mounted.
Upper body 3 is connected to the upper part of body 3.
A seat 4 is installed on the top of the
will be placed. The front wheel 6 has a shaft 7 supported on a cantilever by a knuckle 8, a steering link mechanism 9 is installed from the bar bundle 5 to the knuckle 8, and the knuckle 8 is a leading type front swing that is pivotally supported on the left and right sides of the front part of the vehicle body frame 2. It is supported by arm 11.

The swing arm 11 is composed of two upper and lower arms 12 and a lower arm 13, and a shock absorber 14 and a progressive link mechanism 15 are installed between the swing arm 11 and the front part of the vehicle body frame 2.

In order to support the rear wheels 16, trailing type rear swing arms 21 are pivotally supported on the left and right sides of the rear part of the vehicle body frame 2, and this swing arm 21 is composed of a single piece, and a shock absorber 17 is provided between the rear wheel 16 and the rear part of the vehicle body frame 2. and a progressive link mechanism 18 are installed.

In the above, the support structure for the rear swing arm 21 of the rear wheel 16 is as shown in FIGS. 2 to 4.

That is, in the rear part 24 of the rear swing arm 21, a bearing block 25 is integrally assembled from the rear and up and down directions by connecting with a large number of bolts and nuts as shown in the figure, and at the right end of this bearing block 25 there are two bolts extending vertically. A knuckle holder 26, 26 and one knuckle arm holder 27 extending forward are integrally provided.

The drive shaft 31 is divided into a left shaft 32 and a right shaft 33, and the left end of the right shaft 33 is located within the right end of the left shaft 32 and has an arcuate spline fitting portion 34.
are connected so that they can be bent slightly.

The right half of the left shaft 32 of this drive shaft 31 is rotatably incorporated into the bearing block 25 via the left two rows of ball bearings 35 and the right roller bearing 36, and the right end of the right shaft 33 is provided with a rotational force. A rear wheel hub 38 is connected via a constant velocity ball joint 37 that can be bent while transmitting the same. As shown in the figure, the wheel 16w of the rear wheel 16 and the brake disc 39 are connected to the right end of the rear wheel hub 38 by a plurality of bolts and nuts.

Here, the rear swing arm 21 is formed by bending the middle part to the left, and the wheel 16w of the rear wheel 16 is also formed by displacing the outer peripheral part to the left, and the wheel rim 16r faces inside the middle part of the rear swing arm 21. ing.

A knuckle 41 rotatably supports the rear wheel hub 38.
or may be provided. The knuckle 41 has upper and lower protrusions 42, 42.
and one knuckle arm 43 extending forward are integrally provided, and this knuckle 41 is assembled onto the rear wheel hub 38 via one row of ball bearings 44.

Ball joints 45 and 45 are incorporated into the upper and lower protrusions 42 and 42 of this knuckle 41, respectively, and the horizontal screw members 46 and 46 are connected to the knuckle holder 26.
．． 26 and is connected by screwing. These upper and lower ball joints 45.45 allow the knuckle 41 to bend relative to the knuckle holder 26.26 on the rear swing arm 21 side.

As shown in FIG. 2, when viewed from the side, the line segment connecting the centers A and B of the upper and lower ball joints 45 and 45 passes through the drive shaft center O. In addition, as shown in FIG. 3, the constant velocity ball joint 37 and the ball bearing 44 are arranged above the line segment when viewed from the rear.
Moreover, the line segment has the center of the wheel rim 16r of the rear wheel 16, as shown in FIG. It matches on the IC.

Further, a ball joint 48 is connected to the front end of the knuckle arm 43 by screwing a vertical screw member 47 thereinto, and an elastic device i51 is installed between the ball case 49 and the knuckle arm holder 27. .

The elastic device 51 has a pair of left and right annular elastic rubbers 52.52, and these elastic rubbers 52.52 are baked on the left and right sides of the outer periphery of the inner cylinder 54 to form a flange 55 formed at the center of the outer periphery of the inner cylinder 54.
It is separated by. Further, both elastic rubbers 52 and 52 are incorporated into the outer cylinder 28 at the front end of the knuckle arm holder 27, so that their outer peripheries are in pressure contact with each other, and the inner wall 29 formed at the right end of the outer cylinder 28 and the left end of the outer cylinder 28 are in contact with each other. Left and right elastic rubbers 52 and 52 separated by a flange 55 are adapted to slide individually between a nut member 56 screwed into the part.

The left half of the screw member 57 is inserted into the inner cylinder 54, and the inner cylinder 54 is interposed between a flange 58 formed at the center of the screw member 57 and a nut 59 screwed onto the left end of the screw member 57. functions as a stopper that interferes with the inner wall 29 at the right end of the outer cylinder 28, and the nut 59 functions as a stopper that interferes with the nut member 56 at the left end of the outer cylinder 28,
The right half of the screw member 57 is hingedly connected to the ball case 49.

Here, the left shaft 32 of the drive shaft 31
A driven sprocket 62 is installed on the left half of the engine 1 via a damper device 61, and a chain 63 is hung between the drive sprocket provided on the output shaft (not shown) of the engine 1 and the driven sprocket 62. Further, a rear brake caliber 69 is installed at the rear of the knuckle 41 to apply braking force to the brake disc 39.

In a motorcycle with the above rear wheel support structure, the second
As shown in FIG. 5, the upper and lower pole shims 45.4 connect the protrusions 42, 42 of the knuckle 41 to the knuckle holder 26.26 on the rear swing arm 21 side.
A line segment K connecting the center points A and B of 5 is intersected in side view with a vertical line passing through the grounding point S of the rear tire 16t.
A caster angle θ is provided at 6.

In this embodiment, the line segment K is set to be tilted forward as shown in the figure, and the intersection point T with the ground is placed behind the tire contact point S, thereby generating a negative trail on the rear wheel 16. ing.

Next, rear wheel steering will be explained.

First, the rear wheels 16 can be steered around the line segment, and therefore the line segment is a steering axis.

For example, when the vehicle starts to turn left after traveling straight, a lateral force (centripetal force) F is applied to the tire grounding point S from the right side as shown in FIG. Then, since the intersection point T between the steering axis and the ground is located behind the tire contact point S, the moment around point T is caused by the lateral force F acting on the tire contact point S as shown in Figure 7. The rear wheels 16 are steered to the left side, which is the same as the turning direction.

When the rear wheel 16 turns around the steering axis, the elastic device 51 installed between the knuckle arm 43 and its holder 27 provides resistance to the steering behavior of the rear wheel 16, and The amount of steering is regulated by the stopper function. Moreover, since the horizontal vibrations of the rear wheels 16 that are received during high-speed straight running are absorbed and alleviated by the elastic device 51, the occurrence of cracks is also prevented.

In this way, by setting the rear wheels 16 to be steered in the same direction as the turning direction by lateral force during cornering, lane changes, etc., the cornering power of the tires is generated largely and the turning force is increased.

Here, since it is a motorcycle, it is preferable that the rear wheel steering angle is within a range of about 0.5 degrees at most. This is determined by the positional relationship between the inner wall 29 at the left and right ends of the outer cylinder 28 and the nut member 56.

By the way, the left and right elastic rubbers 52.5 forming the elastic device 51
As shown in Figure 8, there are multiple (three each in the illustration) on the outer periphery of 2.
are formed on the outer periphery of both elastic rubbers 52, 52, respectively.
53 are in pressure contact with the inner peripheral surface of the outer cylinder 28 that is integral with the knuckle arm holder 27.

Both elastic rubbers 52 are baked onto the outer peripheral surface of the inner cylinder 54.
．． 52 is in contact with the left and right surfaces of the flange 55 at the center of the outer circumference of the inner cylinder 54 to apply preload in the axial direction between the inner wall 29 at the right end of the outer cylinder 28 and the nut member 56 at the left end of the outer cylinder 28. Built in condition.

Therefore, in the steering behavior of the rear wheel 16, for example, to the left,
Knuckle arm 43. When the inner cylinder 54 moves to the left in the direction of the arrow in FIG. 8 via the ball bearing 48 and the screw member 57, the flange 55 and the nut member 5 at the left end of the outer #28
6 is compressed and deformed, and the inner circumferential surface of the fixed side outer cylinder 28 is compressed and deformed by both the left and right elastic rubbers 52L.
L.

The annular convex portion 53 on the outer periphery of 52R slides while being pressed against it. Furthermore, when the rear wheel 16 turns to the right, the right elastic rubber 52R is compressed and deformed.

Here, the elastic properties of the elastic rubber 52 as a single item are shown in Figure 9 (
As shown in a), it is a linear characteristic proportional to the stroke (travel amount) and load, and the annular convex portion 53 on the outer periphery of the elastic rubber 52...
The frictional force caused by the pressure contact between the inner circumferential surface of the outer cylinder 28 rises at the beginning of the stroke as shown in FIG. 2(b), and when it exceeds the maximum frictional force, it becomes a low sliding frictional force. The elastic properties of the elastic device 3151 obtained by combining these characteristics rise at the beginning of the stroke, then fall once, and then rise linearly again, as shown in FIG. 2(C). As described above, the use range corresponding to the rear wheel steering angle of up to about 0.5@ is determined by setting the stopper position of the elastic device 51 from the rise at the beginning of the stroke to the part where the stroke falls beyond the maximum value.

That is, the elastic device 51 has an elastic characteristic that provides a high resistance force at the beginning of the steering behavior of the rear wheels 16 due to the lateral force F, and thereafter the resistance force becomes low.

If the elastic device 51 is equipped with an elastic characteristic that provides a high resistance force at the initial stage of the rear wheel steering behavior due to the lateral force F, the rear tire 16t and the vehicle body will be integrated with the vehicle body due to the high resistance force at the initial stage. As shown in Figure 1, which shows the case of a slip angle of 4'' as an example, due to the low resistance force, the rear tire 16t lags behind the vehicle body by 0, s'' due to the low resistance force. cornering force is suppressed, and the vibration of the vehicle body is also damped.

Next, a second embodiment shown in FIGS. 11 and 12 will be described.

This embodiment differs from the above in that the rear swing arm 21 is composed of two upper and lower parallel links, and the structure of other parts is substantially the same as the above.

That is, the rear swing arm 11 consists of two parallel upper and lower arms 22 and a lower arm 23. At the rear ends of the upper and lower arms 22 and 23, upper and lower knuckle holders 26 and 26 of the bearing block 25 are provided.
The screw member 46.46 of the pole joint 45.45 is screwed into the shaft portion 71.71, which is integral with the shaft portion 71.71, or is incorporated therein via a ball bearing 72.72.

In this embodiment as well, the rear wheels 16 are provided with a caster angle θ, and the rear wheels 16 are steered in the same direction as the turning direction due to lateral force during cornering, lane changes, etc., as described above.

In each of the above embodiments, the rear wheels are provided with a negative trail, but as shown in FIG. A positive trail may be generated at the rear wheel 16 by arranging the rear wheel 16 at the rear wheel 16. According to this, the rear wheels 16 can be steered in a direction opposite to the turning direction by the lateral force, thereby improving cornering performance.

It goes without saying that any body structure, front wheel suspension system, and steering system may be used for the motorcycle. Further, various joints, elastic devices, etc. may be appropriately employed, and for example, elastic devices such as hydraulically controlled may be used.

(Effects of the Invention) As described above, according to the motorcycle equipped with the rear wheel support device of the present invention, a line connecting the upper and lower connection points of the knuckle to the arm member side without providing a steering device on the rear wheel side. The rear wheels can now be steered using the rear wheel as the steering axis, and the elastic device installed on the knuckle and arm member side can provide resistance to the rear wheel's steering behavior and regulate the amount of steering. , which absorbs and alleviates the horizontal vibrations of the rear wheels during high-speed driving and prevents the occurrence of breakage. By creating a caster angle, a trail is generated on the rear wheels, and the rear wheels can be steered around the steering axis by the lateral force that acts on the tire ground contact point when the vehicle is steered during cornering or lane changes. Moreover, since the elastic device has elastic properties that provide a high resistance force at the beginning of steering behavior, the rear tires and the vehicle body move as one due to the high resistance force at the beginning, and the vibration amplitude exceeds this. In contrast, the low resistance force suppresses the generation of cornering force and dampens the vibration of the vehicle body.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of the motorcycle according to the first embodiment, Fig. 2 is an enlarged side view showing the area around the rear wheel support, Fig. 3 is a longitudinal cross-sectional view as seen from the rear, and Fig. 4. is a cross-sectional view seen from above, Fig. 5 is a schematic side view showing the relationship between caster angle and trail, Figs. 6 and 7 are schematic plan views explaining the rear wheel steering behavior, and Fig. 8 is a schematic diagram showing the relationship between the caster angle and trail. An enlarged half-cut sectional view of the main part of the device, Figures 9 (a) to (C) are elastic characteristic diagrams for those due to compression, those due to slip, and those due to their combination, and Figure 10 is the relationship between slip angle and cornering force. FIG. 11 is a schematic side view of the motorcycle of the second embodiment, FIG. 12 is an enlarged vertical cross-sectional view of the rear wheel support section seen from the rear, and FIG. 13 is a diagram showing the caster angle and trail. FIG. 7 is a schematic side view showing other settings. In addition, in the drawing, 16 is a rear wheel, 21 is an arm member, 26 is a knuckle holder, 27 is a knuckle arm holder, and 31
is a drive shaft, 37 is a constant velocity joint, 38 is a rear wheel hub, 41 is a knuckle, 43 is a knuckle arm, 45
．． 48 is the ball joint, 51 is the elastic device, 52 is the elastic body, A and B are the connection points, F is the lateral force, is the steering axis, L is the vertical line, 0 is the center of the drive shaft, S is the tire grounding point ,
θ is the caster angle, and θ is the trail.

Claims (1)

[Scope of Claims] An arm member extending rearward from the vehicle body, a drive shaft rotatably supported by the arm member, a rear wheel hub bendably connected to the drive shaft, and a rear wheel hub rotatably supported. A knuckle is bendably connected to the arm member side at two points above and below passing through the center of the drive shaft, and an elastic device is installed between the knuckle and the arm member side, and the upper and lower sides of the knuckle with respect to the arm member side in side view are provided. A caster angle is created for the rear wheels by making the line connecting the two connecting points intersect with the vertical line that passes through the grounding point of the rear tires, and a resistance force is applied to the steering behavior of the rear wheels to regulate the steering behavior. What is claimed is: 1. A rear wheel support device for a motorcycle, comprising: an elastic device having an elastic property that provides a high resistance force at the initial stage of steering behavior.