JP3412788B2 - 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]

In Japanese Patent Laid-Open No. 4-353090, one end of a link arm is pivotally supported on the lower end of a front fork, and a front wheel is supported on the other end, and a front cushion is provided between the intermediate part of the link arm and the front fork. A front wheel drive device that employs the provided bottom ring type suspension and that has a two-stage chain is shown.

The first-stage chain is wound around the upper part of the front fork and between the idlers provided at the pivot points of the link arms, and the second-stage chain is located between the idler and the front wheel sprockets on the front axle. Wrapped around,
In addition, the drive side line passes below the link arm.

Further, JP-A-58-206477 discloses that
It has the same bottom ring type suspension, and connects the upper end of the front fork and the front wheel sprocket with a one-step chain, and changes the direction of the drive side line with an idler provided on the fulcrum of the link arm. It is shown.

[0005]

In each of the above conventional sides, the idler is provided on the shaft fulcrum of the link arm.
The drive side line of the chain, which is a winding transmission member, does not intersect the link arm and passes below the link fulcrum, apart from the shaft fulcrum.

Therefore, when a driving force is applied to the chain, a moment is generated due to the pulling force to rotate the tip end side of the link arm downward around the pivot point.

However, since the front wheels are in contact with the ground, this moment acts in a direction to extend the front cowl upward, which causes a lift phenomenon of lifting the front portion of the vehicle body. Therefore, a front wheel drive device that can eliminate such a lift phenomenon is desired.

[0008]

According to a first aspect of the present invention, a front wheel is supported on the other end of a link arm whose one end is supported by a front fork, and a cushion for a front wheel suspension is attached to the link arm and the front wheel is wound. In motorcycles that drive the front wheels by hanging transmission, the drive side line of the winding transmission member is on the fulcrum of the link arm.
Characterized by being arranged to passing so that.

[0009]

According to a second aspect of the invention, in the invention of the first aspect, an idler for bending the drive side line of the winding transmission member so as to pass on the shaft fulcrum is attached to the front fork. To do.

According to a third aspect of the invention, in the invention of the first aspect, an idler for bending the driving side line of the winding transmission member so as to pass on the shaft fulcrum is attached to the link arm portion. And

[0012]

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 mounted on the front surface of the direction changing gear case 5 which is provided above the front fender 4 at the intermediate portion of the front fork 2.

On a vehicle body frame (described later) which supports the front fork 2, a fuel tank 7 and a cargo bed 8 extending obliquely upward and rearward from the back surface thereof are supported, and a seat 9 is supported above an intermediate portion of the cargo tank 8. There is.

In the vehicle body frame, a head pipe 10 for rotatably supporting the front fork 2 is attached to the front end portion via a gusset 11 and extends in the front-rear direction, and a main pipe 12 is integrated in 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 at a rear portion of the body portion 13, and a rear wheel 18 is supported at a rear end portion thereof, and a rear upper portion of the body portion 13 and a rear portion of the rear swing arm 17 are supported. 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 a link arm 27, which supports the axle 25 at one end, is rotatably supported at the lower end 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 an enlarged side perspective view of the front suspension and front wheel drive portion, and FIG. 4 is a front side perspective view of this portion.

As is apparent from these figures, the direction change gear train 23 includes an input shaft gear 41, an intermediate shaft gear 42 meshing with the input shaft gear 41, an intermediate shaft bevel gear 44 coaxial therewith,
The output shaft bevel gear 45 meshes with this.

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 arranged 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.

The other end of the direction changing section output shaft 46 is provided with a direction changing section driving sprocket 47, 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 forks 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 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 is apparent from FIG. 3, the idler 48 is supported at a position where the driving side line 50 just passes over the pivot 28.

Therefore, when a driving force is applied to the front wheel sprocket 25 through the chain 24, the tensile force generated in the driving side line 50 will pass on the pivot 28 as indicated by P in the figure. Therefore, the lift phenomenon unlike the conventional case does not occur.

FIG. 5 is a deformation example of some modifications,
The idler 48 is rotatably supported at a position above the pivot 26 by a mounting portion 52 formed on a part of the link arm 27.

However, the point that the drive side line 50 passes over the pivot 28 is the same as before. In this way, even if the link arm 27 swings, the idler 48 follows this. The drive-side line 50 can be prevented from shifting from the pivot 28.

[0035]

[0036]

[0037]

[0038]

The present invention can be modified in various ways.
For example, a belt can be driven as a winding transmission member that changes to a chain. It can also be applied to a motorcycle.

[0040]

Effects of the Invention According to claim 1 the invention is characterized in that arranged the drive side line of the wrapping connector member on the pivot point of the link arm through so that.

[0041]

[0042]

Therefore, since the tensile force generated along the driving side line acts on the pivot point, the link arm can be reliably prevented from swinging due to the driving force.

The invention according to claim 2, wherein in the invention according to the first, fitted with idler for bending the driven side line of the wrapping connector member on the shaft fulcrum through so that the front fork.

With this arrangement, the driving side line can be easily set and the degree of freedom regarding the attachment position of the idler is increased .

According to the invention of claim 3 , in the invention of claim 1, the idler is attached to the link arm. Accordingly, even if the link arm swings, the idler follows this, so that the drive line can be prevented from shifting from the shaft fulcrum.

[Brief description of drawings]

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

FIG. 2 is a left perspective view of the same as above.

FIG. 3 is a side perspective view showing a front suspension and a front wheel drive unit.

FIG. 4 is a diagram showing the same part as above from the front.

FIG. 5 is a graph showing the change Katachirei

[Explanation of symbols]

1: front wheel, 2: front fork, 24: chain, 2
6: front wheel sprocket, 27: link arm, 28: pivot, 50: drive side line

Claims (3)

(57) [Claims] Claims: 1. An automatic two- or three-wheel system in which a front wheel is supported on the other end of a link arm whose one end is supported by a front fork, a cushion of a front wheel suspension is attached to the link arm, and the front wheel is driven by winding transmission. in the car, automatic, characterized in that the drive-side line of the wrapping connector member is disposed on the pivot point of the link arm through so that 2
-Front wheel drive for three-wheeled vehicles. 2. The motorcycle of claim 1, wherein an idler for bending the drive side line of the winding transmission member so as to pass on the shaft fulcrum is attached to the front fork. Front wheel drive. 3. The motorcycle of claim 1, wherein an idler for bending the drive side line of the winding transmission member so as to pass on the shaft fulcrum is attached to the link arm. Front wheel drive.