JPH0615817Y2 - Rear wheel support device for motorcycles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a motorcycle having a cantilever type swing arm at the rear of the vehicle body, in which the rear wheel is attached to the end of the rear axle in a center lock manner. Regarding things.

[Prior Art] A motorcycle having a cantilever type swing arm for supporting a rear wheel is known, and a rear axle is passed through a center portion of a wheel hub of the rear wheel to prevent a locking member such as a center nut. A so-called center lock type in which both are connected by only one is also known. An example of such a structure is disclosed in JP-A-62-20780.
In this structure, an axle flange is provided on the middle part on one side of the rear axle, and a threaded portion is formed at the tip of the rear axle, and this threaded portion penetrates the mounting hole at the center of the wheel hub of the rear wheel and projects outward. By fastening the center nut to this, the inner end surface of the wheel hub is forcibly brought into contact with the axle flange, and the wheel hub is sandwiched between the center nut and the axle flange. The contact portion between the center nut and the wheel hub is tapered so that the rear axle can be aligned when the center nut is fastened.

In addition, at the contact part between the axle flange and the wheel hub,
The entire inner end surface of the wheel hub contacts the axle flange.

[Problems to be Solved by the Invention] In the case of the above structure, the coupling force between the rear axle and the rear wheel is obtained by the frictional force at each contact surface between the wheel hub, the center nut, and the axle flange. Therefore, when the rear wheels try to swing in the left-right direction with respect to the center line of the vehicle body during cornering while traveling, a force in a direction inclined with respect to the axis of the rear axle is applied to each contact surface. At this time, the contact part between the center nut and the wheel hub should be
Since the component force acts in the diffusion direction along the tapered surface, the binding force becomes small. Furthermore, at the contact surface between the wheel hub and the axle flange, an attempt is made to create an inclination with the inner peripheral edge of the wheel hub as the fulcrum, so the innermost part of the contact portion of the wheel hub with respect to the axle flange and the axial center part. The radius between them (hereinafter referred to as the contact radius) becomes smaller, and the binding force also becomes smaller.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rear wheel support device of the center lock type, which can further enhance the coupling force between the wheel hub of the rear wheel and the rear axle.

[Means for Solving Problems] A rear wheel supporting device for a motorcycle according to the present invention includes a cantilever type swing arm having a front end pivotally attached to a frame of the motorcycle, and a rear end of the cantilever swing arm. A rear axle having an axle flange that is rotatably supported by the rear axle and that extends in a radial direction at an intermediate portion, and a rear wheel having a wheel hub attached to one end of the rear axle. The inner end surface of the wheel hub is forcibly brought into contact with the axle flange by a lock member that is fastened to the tip of the rear axle that penetrates from the outside of the vehicle body, and the contact surface between the lock member and the wheel hub is the rear axle. While being formed in a direction orthogonal to the axis line of, the inner end surface of the wheel hub, the inner peripheral side portion is a recess not in contact with the axle flange, It is characterized in that it is configured so as to contact with the axle flange only at the outer peripheral side of the recess.

[Advantage of the Invention] When the rear wheel swings in the left-right direction with respect to the center of the vehicle body, a force in a direction inclined with respect to the axis of the rear axle is applied to each contact surface between the wheel hub, the lock member and the axle flange. At this time, at the contact surface between the lock member and the wheel hub, both are in contact with each other in a plane orthogonal to the rear axle, so most of this force is received from the right angle direction, and the decrease in coupling force is small. .

Further, since the inner end surface of the wheel hub has a concave portion formed in the vicinity of the rear axle on the inner peripheral side, the inner peripheral portion thereof is not in contact with the axle flange, and only the outer peripheral portion is in contact with the axle flange. Therefore, even when such a force is applied, it is possible to maintain a relatively large contact radius and obtain a predetermined coupling force.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention.

FIG. 1 is a partially cutaway view showing the overall plan view of the rear wheel support system of a motorcycle, and FIG. 2 is an enlarged view showing the joint between the rear axle and the wheel hub, and FIG. FIG. 4 is a diagram showing an enlarged partial cross section thereof. A cantilever swing arm 1 curved in a substantially S shape is pivotally attached to a rear end portion of a main frame F by a shaft 3 at a front end portion 2 thereof, and a known eccentric unit 4 for chain tension adjustment is provided at the other end portion. The rear axle 5 is rotatably supported via the. The eccentric unit 4 is supported by a cylindrical holder portion 1a formed at the rear end portion of the cantilever swing arm 1 so as to be able to rotate inward, and the divided portion 1b of the holder portion 1a is fastened with a bolt 1c. It is fixed by.

The rear axle 5 is a hollow shaft, and one end of the rear axle 5 projects to one side of the cantilever type swing arm 1, to which a driven sprocket 6 is attached by spline connection and fixed by a lock nut 7. The other end of the rear axle 5 projects toward the other end of the cantilever swing arm 1,
An axle flange 8 extending in the radial direction is formed in the middle of the protruding portion.

On the other hand, the rear wheel 10 has a wheel hub 13 formed at a central portion of a spoke 12 to which a tire 11 is mounted, and a front end side of an axle flange 8 of a rear axle 5 is fitted into a mounting hole formed at a central portion thereof. There is. Reference numeral 14 is an outer tightening surface of the wheel hub 13, and 15 is an inner tightening surface that is forcibly contacted with the axle flange 8 and forms a part of the inner end surface of the wheel hub 13. The inner end surface of the wheel hub 13 is formed with a recess 16 concentrically surrounding the rear axle 5 on the inner peripheral side, and has a clearance (see FIG. 3) between the axle flange 8 and the axle flange 8. It is a contact part. Therefore, the inner tightening surface 15 is formed only on the outer peripheral side portion of the recess 16. A hole 13a is formed in the inner tightening surface 15, and a pin 17 attached to the axle flange 8 engages with the hole 13a to prevent rotation between the two.

An annular recess 13b is formed in the center of the inner periphery of the wheel hub 13 along the rear axle 5, and a step 13c is formed on the outer tightening surface 14 side with the annular recess 13b sandwiched between the inner recess 13b and the inner recess. A step portion 13d is also formed on the attachment surface 15 side. These step portions 13c and 13d are portions that come into contact with the rear axle 5, and in particular, the contact surfaces of the step portions 13c and 13d and the rear axle 5 are required to be dimensionally controlled with high accuracy for the purpose of alignment. Further, tapered cut portions 13e and 13f are formed on the step portion 13d, and the cut portion 13f facilitates fitting the wheel hub 13 toward the axle flange 8 of the rear axle 5.

Inside the rear axle 5, a long tension bolt 2
0 is internally provided, and a head portion 21 (see FIG. 1) thereof is axially prevented from slipping off at a step portion formed inside the rear axle 5 on the driven sprocket 6 side, and is also prevented from rotating by spline coupling. A screw portion 22 is formed on the other end of the tension bolt 20. This part projects from the open end of the rear axle 5,
A lock member 25 including a center nut 23 and a seat portion 24 is attached here. Reference numeral 26 is a retaining pin.

As shown in FIG. 3, the lock member 25 is in contact with the outer tightening surface 14 at the seat portion 24. It should be noted that this contact surface is formed so as to be in a plane orthogonal to the rear axle 5. The step portion 24 a formed inside the seat portion 24 is fitted in the mounting hole of the wheel hub 13 and forms a slight gap with the end surface of the axle flange 8. Further, the inner tightening surface 15 and the axle flange 8 are also in contact with each other in the plane orthogonal to the rear axle 5.

In FIG. 2, reference numeral 30 is a brake disc, 31 and 32 are the mounting nuts, 33 is a brake caliper, 3
Reference numeral 4 is a brake caliper bracket, and 35 is a connecting rod forming a part of the brake torque rod, which crosses the cantilever swing arm 1. The symbol C in FIG. 1 is the vehicle body center line.

Next, the operation of this embodiment will be described. First, in order to remove the rear wheel 10 from the mounted state of the rear wheel shown in the figure, first, the retaining pin 2
6 is removed, the center nut 23 is loosened, and it is removed together with the seat portion 24. As a result, when the rear wheel 10 is pulled outward in the axial direction of the rear axle 5, the wheel hub 13 is easily separated from the axle flange 8 and the rear wheel 10 is disengaged from the rear axle 5. In order to mount the rear wheel 10, the wheel hub 13
A mounting hole provided at the center of the rear axle 5 is fitted into the end portion of the rear axle 5, and the pin 17 mounted on the axle flange 8 is engaged with the hole 13a of the wheel hub 13. Next, the seat portion 2 that passes through the screw portion 22 of the tension bolt 20 as a center
4 is fitted into the end opening of the rear axle 5, and the center nut 23 is fastened to the screw portion 22. When the center nut 23 is tightened with a predetermined torque, the seat portion 24 is moved to the wheel hub 13
Is pressed against the outer clamping surface 14, and at the same time, the inner clamping surface 15 is forcibly pressed against the axle flange 8. Therefore, the inner and outer side surfaces of the wheel hub 13 are pressed against each other between the seat portion 24 and the axle flange 8 to be coupled to the rear axle 5. Therefore, the rear wheel 10 can be quickly attached and detached, and the maintainability is greatly improved.

In this rear wheel mounted state, the coupling force between the rear wheel 10 and the rear axle 5 depends on the frictional force of each contact surface on both inner and outer side surfaces of the wheel hub 13.

Therefore, when the rear wheel 10 swings in the left-right direction with respect to the vehicle body center line C during cornering or the like while the motorcycle is running, a force in a direction inclined with respect to the axis of the rear axle 5 is applied to each contact surface. . At this time, at the contact surface between the seat portion 24 and the outer tightening surface 14, since the contact surface is in the plane orthogonal to the axis of the rear axle 5, most of this force is applied from a direction substantially perpendicular to the contact surface. That means the rear wheel 1
It retains a binding force that is not much different from a straight traveling state of 0.

Further, at the contact surface between the axle flange 8 and the inner tightening surface 15, the contact radius with the axial center portion of the rear axle 5 is R ₁ , which is far larger than the contact radius R ₂ assuming that the recess 16 is not formed. Grows to. Therefore, the surface pressure applied to the contact portion is increased accordingly, and accordingly, a larger coupling force between the axle flange 8 and the inner tightening surface 15 can be secured.

Since the tension bolt 20 is used in this embodiment, the center nut 23 can be more securely prevented from loosening.
However, the present invention is not limited to the above embodiment, and various applications are possible. For example, a screw portion is directly provided on the end portion of the rear axle 5 and a large diameter center nut or the like is used as a lock member. It is also possible to conclude directly.

[Effect of the Invention] The present invention adopts the center lock type, but the contact between the lock member and the wheel hub is made in a plane orthogonal to the rear axle, and the contact between the wheel hub and the axle flange is made. Since the operation is performed only on the outer peripheral side, the coupling force between the rear wheel and the rear axle during cornering or the like can be increased more than before.

Moreover, because of the center lock type, good maintainability can be maintained.

[Brief description of drawings]

1 to 3 show an embodiment, FIG. 1 is a partially cutaway plan view of a rear wheel support device in a motorcycle, and FIGS. 2 and 3 are enlarged sectional views of essential parts. . (Description of symbols) 1 ... cantilever type swing arm, 5 ... rear axle, 8 ... axle flange, 10 ... rear wheel, 13 ... wheel hub, 1
6 ... Recessed part, 20 ... Tension bolt, 23 ... Center nut, 24 ... Seat part, 25 ... Lock member.

Claims (1)

[Scope of utility model registration request] A cantilever type swing arm whose front end is pivotally attached to the frame of the motorcycle, and a rear axle which is rotatably supported at the rear end thereof and is provided with an axle flange extending in a radial direction at an intermediate portion, A rear wheel having a wheel hub attached to one end of this rear axle is provided, and the inner end surface of the wheel hub is connected to the axle flange by a locking member that is fastened from the outside of the vehicle body to the rear axle tip that penetrates the center of the wheel hub. In the rear wheel support device forcibly brought into contact, a contact surface between the lock member and the wheel hub is formed in a direction orthogonal to an axis of the rear axle, and an inner end surface of the wheel hub has an inner peripheral side thereof. A portion is a concave portion that is not in contact with the axle flange, and the outer peripheral portion of the concave portion is in contact with the axle flange only. Wheel supporting apparatus after the motorcycle, characterized by being made.