JP3412786B2 - Front wheel drive for automatic two- and three-wheeled vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel drive device for a two-wheeled and three-wheeled vehicle.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 60-176881 discloses a front-wheel drive type two-wheeled vehicle, in which a drive shaft and a direction changing gear box provided on a front fork side are connected by a joint on a steering axis. The front wheels are belt driven from the output shaft side of the joint.

The axis of the output shaft of this joint (that is, the input shaft of the direction changing gearbox) is substantially orthogonal to the steering axis, but the drive shaft serving as the input shaft of the joint intersects the steering axis obliquely in a side view. .

Further, in Japanese Patent Laid-Open No. 4-353090, a joint is provided on the steering axis, and its input shaft and output shaft are arranged in the vehicle width direction, and when viewed from the front, the respective axes become the steering axis. A front wheel drive device for a motorcycle is shown in which the input shaft is connected to the engine side and the output shaft is connected to the front wheel side while making them orthogonal to each other.

[0005]

FIG. 8 shows a moment generated around the steering axis by the transmitted driving force when the angle θ (less than 90 °) between the input axis and output axis of the joint and the steering axis is ( The principle of steering shaft moment, MS) will be shown below.

FIG. 8A shows the case where the input shaft of the joint forms an angle θ with the steering axis ST and the output shaft of the joint is 90 °, and FIG. 8B shows that the input shaft conversely intersects the steering axis ST at right angles. However, the output shaft forms an angle θ.

First, in FIG. 8A, the surface A is a plane orthogonal to the steering axis ST, T is a tangential force given around the steering axis ST by the rotation of the input shaft, and Rn is the rotation of the input shaft. The radius, Rs, is the radius from the contact point between the rotating circle of the input shaft having the radius Rn and the surface A to the steering axis ST.

In this case, the input moment is T × Rn, and as a result, the steering axis moment generated around the steering axis ST is MS = T × Rs.

The same applies to B in FIG. However, in this case,
The rotation circle inclined with respect to the plane A is on the output shaft side, and similarly, if the rotation radius is Rn, output moment = T * Rn MS = T * Rs.

That is, when either the input shaft or the output shaft intersects with the steering axis ST at a certain inclination without being orthogonal to each other, the respective rotational driving forces generate a steering shaft moment MS around the steering axis ST, and as a result, , Will require special handling techniques.

The above-mentioned Japanese Patent Laid-Open No. 60-176881 has exactly such a problem. Further, in Japanese Patent Laid-Open No. 4-353090, both the input shaft and the output shaft are orthogonal to the steering axis ST, so that although such a steering shaft moment can be prevented from occurring, these shafts are steered in the vehicle width direction ST. Since it is provided so as to intersect with the vehicle, the dimension in the vehicle width direction is enlarged, and it becomes impossible to slim the vehicle body.

[0012]

The invention according to claim 1 is
Gase is located above the front end of the main pipe that makes up the body frame.
The head pipe is installed through the
Place the passed drive shaft in the front-rear direction and
The jaws provided below the saddle pipe and in front of the main pipe.
Connected to the inlet, and in front of the joint,
, The driving force is redirected backwards
It is transmitted to the driving sprocket on the upper part of the
Check the chain between the dynamic sprocket and the sprocket on the front wheels.
The drive shaft is arranged in the front-rear direction and the output shaft of the joint is arranged in the extension direction of the drive shaft in a side view, and the output shaft of the joint and the drive shaft are respectively aligned with the axis of the head pipe. It is characterized by being orthogonal.

The invention according to claim 2 is characterized in that, in the invention of claim 1, the drive shaft is provided along the center of the vehicle body in a plan view.

According to a third aspect of the invention, in the first aspect of the invention, the drive shaft is disposed obliquely with respect to the center of the vehicle body in a plan view.

[0015]

DETAILED DESCRIPTION OF THE INVENTION

[0016]

1 is an overall side view of a motorcycle applied to the present invention, and FIG. 2 is a diagram showing a drive system.

As is apparent from these figures, the front wheel 1 is supported by a front fork 2, and a handle 3 is attached to the upper end of the front fork 2.

A front carrier 6 is attached to a front surface of a direction changing gear box 5 which is provided above the front fender 4 at an intermediate portion of the front fork 2.

On a vehicle body frame (described later) that supports the front fork 2, a fuel tank 7 and a luggage carrier 8 extending obliquely upward and rearward from the rear surface thereof are supported, and a seat 9 is supported above the middle portion of the cargo carrier 8. There is.

In the vehicle body frame, a head pipe 10 for rotatably supporting the front fork 2 is attached to a front end portion via a gusset 11, and a main pipe 12 extending in the front-rear direction is integrated with the rear end portion in a left-right alignment. And a body portion

An engine 14 is supported by the body portion 13, and an air cleaner 16 is connected to an intake passage of the engine 14 through a carburetor 15. The air cleaner 16 is supported by the main pipe 12.

Further, a rear swing arm 17 is rotatably supported on the rear portion of the body portion 13, and a rear wheel 18 is supported on the rear end portion thereof. Between the rear cushion 19
Is installed.

This motorcycle is of the front and rear wheel drive type,
The front wheel drive system is the front wheel power take-off shaft 2 provided in the engine.
From 0 to the direction change gear train 23 in the direction change gear case 5 via the drive shaft 21 and the joint 22 which are rotatably supported in the main pipe 12, and are further transmitted to the axle 25 of the front wheel 1 by the chain 24. It is transmitted to the supported front sprocket 26.

In the front wheel suspension, the other end of the link arm 27, which supports the axle 25 at one end, is rotatably supported to the lower end portion of the front fork 2 by a pivot 28, and the middle portion of the link arm 27 and the front fork 2 are supported. Front cushion 2 attached to the pivot 28 upper position and
It is composed of 9.

The rear wheel drive system includes a chain 33 between an output sprocket 31 and a rear wheel sprocket 32 provided at one end of a rear wheel power output shaft 30 arranged in the engine 14.
It is configured by wrapping around.

FIG. 3 is a side perspective view of the front wheel suspension and the front wheel drive portion, and FIG. 4 is a front side perspective view thereof.
FIG. 5 is a plan sectional view of the front wheel drive device portion.

First, referring to FIG. 5, the rear wheel power output shaft 30 is shown.
Has an output sprocket 31 at one end, and a first gear 34 provided at an intermediate portion meshes with a second gear 35 on the front wheel power output shaft 20.

The front wheel power output shaft 20 is a rear wheel power output shaft 30.
Parallel to the inner shaft 36 and the outer shaft 3 fitted around the inner shaft 36.
The second gear 35 is attached to the outer shaft 38, and the inner and outer sides of the torque limiter 37 are separately attached to the shaft ends of both shafts on the left side in the traveling direction of the vehicle body. .

A first bevel gear 38 is attached to the shaft end of the inner shaft 36.
a is provided, which meshes with the second bevel gear 39, and the second bevel gear 39 is connected to the drive shaft 21.
Is attached to the shaft end of the drive shaft 21, that is, the axis of the drive shaft 21 coincides with the center C of the vehicle body.

With this configuration, the torque limiter 3
Since the input side and the output side of 7 are on the same side, the maintainability is improved and the front wheel power take-off shaft 20 can be shortened as a whole, and the differential mechanism can be made compact and at the same time reduce the weight.

As is apparent from FIGS. 3 and 4, the direction change gear train 23 includes an input shaft gear 41, an intermediate shaft gear 42 meshing with the input shaft gear 41, and an intermediate shaft bevel gear 4 coaxial with the input shaft gear 41.
4, an output shaft bevel gear 45 meshing with the output shaft bevel gear 45.

The direction changing portion input shaft 40 provided with the input shaft gear 41 has one end connected to the output side of the joint 22 and is disposed on an extension line of the drive shaft 21 in a side view.

Intermediate shaft gear 42 and intermediate shaft bevel gear 44
The direction change part intermediate shaft 43 provided at both ends extends vertically below and parallel to the direction change part input shaft 40, and the direction change part output shaft 46 provided with the output shaft bevel gear 45 at one end is It extends in the vehicle width direction orthogonal to the intermediate shaft 43 of these direction changing parts.

A direction changing part driving sprocket 47 is provided at the other end of the direction changing part output shaft 46, and the chain 24 is wound between this and the front wheel sprocket 26.

Therefore, the driving force transmitted from the drive shaft 21 to the front is U-turned by the direction changing gear train 23 to be directed to the rear, and is further directed downward to drive the chain along the front fork 2 by the front wheel sprocket 26. Transmitted to.

A portion of the chain 24 near the front wheel sprocket 26 is bent forward by an idler 48 and a tension roller 49, and the driving side line 50 is bent so as to pass over the pivot 28 and then extends substantially along the link arm 27. .

The tension roller 49 is pressed against the chain 24 by a spring in order to remove the looseness of the chain 24. The symbol P in the figure is the tensile force of the chain.

The upper part of the chain 24 is the front fork 2
It is accommodated in a chain case 51 extending vertically along the inside of the idler, and an idler 48 and a tension roller 49.
Is also housed and supported here.

As shown in FIG. 5, the main pipe 12 is arranged in the front-rear direction with its central axis overlapping the center C of the vehicle body. The drive shaft 21 inserted into the main pipe 12 as well as the joint 22 during straight traveling. The input shaft 52 and the output shaft 40 of the direction changing portion, which is the output shaft, are also aligned on the center C of the vehicle body.

As is apparent from FIG. 3, the joint 22 is on the steering axis ST, and the input shaft 5 of the joint 22.
Drive shaft 21 connected to 2 and joint 22
The input shaft 40, which is the output shaft of the steering wheel, is orthogonal to the steering axis ST in a side view.

Therefore, it is possible to prevent the steering shaft moment from being generated around the steering axis ST even by the rotational driving force of the drive shaft 21, and the handling becomes easy.

Moreover, as is apparent from FIG. 5, the axis of the drive shaft 21 coincides with the center C of the vehicle body. Therefore, the heavy drive shaft 21 is located at the center C of the vehicle body.
Since it is located on the upper side, the weight balance on the left and right becomes good.

Moreover, since the direction change gear train 23 is connected to the drive shaft 21 in the extension direction thereof (when traveling straight),
Since the input shaft 52 and the output shaft of the joint 22 are arranged in the front-rear direction and the protrusion in the vehicle width direction is eliminated, the vehicle body can be made slim in the vehicle width direction, and further slim by the adoption of the compact differential mechanism. it can.

FIG. 6 is a side view of the modified example, and FIG. 7 is a plan sectional view of the front wheel drive system thereof. In this example, the main pipe 12 intersects the vehicle body center C at an angle α, and the rear side That is, the engine side opens laterally from the center C of the vehicle body, and the sub-pipes 53 are provided substantially symmetrically on the opposite side of the vehicle body.

The distance between the rear ends of the main pipe 12 and the sub pipe 53 corresponds to the width of the vehicle body, and a relatively large space 54 is formed inside both pipes. For this reason, the differential mechanism such as the torque limiter 37 is arranged in the direction opposite to that shown in FIG.

Furthermore, since the intake system parts such as the engine cylinder 55 and the carburetor 15 can be accommodated in the space 54, the layout of the parts can be facilitated.

Even in this way, the drive shaft 21
Also, there is no change in that the direction changer input shaft 40 is orthogonal to the steering axis ST, and the occurrence of the steering shaft moment can be prevented. The present invention is not limited to the above embodiment.
It can be modified in various ways, and can be applied to, for example, a motorcycle.
It

[0048]

According to the invention of claim 1, the body frame is
A gusset is installed above the front end of the main pipe.
Drive with a dead pipe installed and passed through the main pipe
Place the shaft in the front-back direction and place the front end under the head pipe.
Connection to the joint located in front of the main pipe
Install a direction change gearbox in front of the joint.
The drive force is changed to the rear and the front fork upper part
To the driving sprocket installed on the
Wrap the chain between the wheel and the sprocket on the front wheels.
The drive shaft is mounted in the front-rear direction, the output shaft of the joint is arranged in the extension direction of the drive shaft in a side view, and the output shaft of the joint and the drive shaft are orthogonal to the axis of the head pipe.

Therefore, it is possible to prevent the steering shaft moment from being generated around the steering axis even by the rotational driving force of the drive shaft, and the handling becomes easy.

Moreover, since the direction changing gear train is connected to the drive shaft in the extension direction thereof (when traveling straight), the input shaft and the output shaft of the joint are arranged in the front-rear direction and there is no overhang in the vehicle width direction. The body can be made slim in the vehicle width direction.

According to the invention of claim 2, in the invention of claim 1, since the drive shaft is provided along the center of the vehicle body in a plan view, it is possible to position the heavy drive shaft on the center of the vehicle body. Good left / right weight balance.

According to the invention of claim 3, in the invention of claim 1, since the drive shaft is disposed obliquely with respect to the center of the vehicle body in a plan view, it is possible to prevent the generation of the steering shaft moment as before, and A relatively large space is formed on the center side of the vehicle body, and the intake system components such as the torque limiter, the engine cylinder, and the carburetor can be accommodated in this space as appropriate, which facilitates the layout of the components.

[Brief description of drawings]

FIG. 1 is an external side view of a motorcycle to which the present invention is applied.

FIG. 2 Same as above, perspective view on the left side

FIG. 3 is a side perspective view of a front wheel drive device.

FIG. 4 is a front perspective view of the same.

FIG. 5 is a plan view of a drive shaft.

FIG. 6 is a side view of a modified example.

[Figure 7] Plan view in section

FIG. 8 is a diagram illustrating a principle of generating a steering shaft moment.

[Explanation of symbols]

2: front fork, 5: direction change gear box, 2
1: Drive shaft, 22: Joint, 40: Direction changing part input shaft, ST: Steering shaft

Claims (3)

(57) [Claims] Claims: 1. A front pipe is rotatably supported by a head pipe provided on a vehicle body frame, and a drive shaft provided on the vehicle body frame side and an output shaft of a direction changing gear box provided on the front fork side are joined. In a front-wheel drive device for a motorcycle, which is connected via a drive shaft and transmits the drive force of a drive shaft from a direction changing gear box to front wheels, a main pie constituting a body frame.
A head pipe is provided above the front end of the butt via a gusset,
Drive shaft passed through the main pipe in the front-back direction
The front end below the head pipe and the main pipe.
Connect to the joint provided in front of the
A direction change gear box is installed on the
Converted and installed on the front fork
To the driving wheel and the sprockets on the front wheels.
The chain is wound between rockets, and the output shaft of the joint is arranged in the extension direction of the drive shaft in side view , and the output shaft of the joint and the drive shaft are respectively orthogonal to the axis of the head pipe. Front wheel drive for motorcycles. 2. The automatic transmission according to claim 1, wherein the drive shaft is provided along the center of the vehicle body in plan view.
Front-wheel drive for three-wheeled vehicles. 3. The front wheel drive system for a motorcycle of claim 1, wherein the drive shaft is arranged obliquely with respect to the center of the vehicle body in a plan view.