JP3412787B2 - 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 In Japanese Examined Patent Publication No. 40-26092, a drive shaft extending forward from an engine is connected to a direction changing gear box extending forward from a steering axis, and a main driving sprocket and a follower at the tip of the direction changing gear box are connected. A front wheel drive for a motorcycle driven by a chain wrapped around a front wheel sprocket on the side is shown.

Further, Japanese Patent Laid-Open No. 59-114185 discloses that
There is shown a type in which a direction changing gear box provided in front of a head pipe raises power once and then bends it downward and transmits it again.

[0004]

With the constructions of the above-mentioned respective known examples, since the direction change gearbox having a relatively large weight is formed in front of the head pipe whose central axis corresponds to the steering axis, the steering inertial force is increased. The moment increases, making it difficult to achieve light handling.

In addition, since a relatively large direction changing gear box presses the space in front of the head pipe, when arranging a luggage basket, headlights, etc. at this portion, the mounting position of these becomes high, which increases the weight of the vehicle. It tends to be closed.

Further, since the direction changing gearbox is located relatively forward from the center of gravity of the vehicle, it becomes difficult to balance the weight of the vehicle body in the front-rear direction.

[0007]

According to a first aspect of the present invention, a drive shaft provided in the front-rear direction of a vehicle body is connected by a joint to a direction changing gear box provided in front of a front fork, and the direction changing gear box is provided. In a front-wheel drive device for a two- and three-wheeled vehicle that drives front wheels by switching the power transmission direction from the front-rear direction to the up-down direction, a direction-changing gearbox has a direction-changing portion input having an axis orthogonal to the axis of the head pipe. A shaft, a direction-changing part intermediate shaft which vertically overlaps the direction-changing part input shaft and extends parallel to the front-rear direction, and a direction-changing part extending perpendicularly to the rear end of the direction-changing part intermediate shaft to one side in the vehicle width direction. With an output shaft,
This direction changer output shaft , direction changer input shaft and direction changer
It is characterized in that the replacement portion intermediate shaft is arranged below the head pipe and near the axis.

According to a second aspect of the present invention, in the invention of the first aspect, a main rotating member is provided on the output shaft of the direction changing portion, and a winding transmission member for driving front wheels is wound around the main rotating member, and the main rotating member is provided on the side surface. It is characterized in that it is arranged at a position overlapping the front fork when viewed.

[0009]

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 the 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 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 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. The rear end upper portion of the body portion 13 and the rear portion of the rear swing arm 17 are supported. Between the rear cushion 19
Is installed.

This motorcycle is a 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 at the lower end portion of the front fork 2 by a pivot 28, and the intermediate 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 device 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 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 drive side line 50 is bent so as to pass over the pivot 28 and then extends substantially along the link arm 27. . The symbol P in the figure indicates the tensile force of the chain.

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 direction changing section output shaft 46 is located in the vicinity of the head pipe 10, and the center line of the head pipe 10 coincides with the steering axis ST.
The position is extremely close to the steering axis ST.

By doing so, the output shaft 46 of the direction changing portion
And the output shaft bevel gear 45 directed to the inner end thereof
Can be accommodated in a relatively wide space 52 formed below the head pipe 10 and the joint 22 and between the rear part of the front fender 4 and a portion that curves rearward and downward.

Therefore, the amount by which the upper portions of the direction changing gear box 5 and the chain case 51 project toward the front of the head pipe 10 can be reduced, and as a result, the steering moment of inertia can be reduced and light handling is possible.

That is, for comparison, FIG. 5 is a view showing a hypothetical example as A and the present invention as B as being vertically aligned with the axles 25 aligned. In the hypothetical example of A,
The direction changing portion output shaft 46a is projected in the forward extension direction of the drive shaft 21, and the position thereof is forward by the dimension L from the present invention.

Therefore, in the hypothetical example, the position of the direction change gear box 5 having a relatively large weight is determined by the steering axis S.
Although the steering moment of inertia becomes relatively large as a result of being far away from T, the present invention can make the steering moment of inertia much smaller than the case of the hypothetical example, and the front-rear weight balance becomes excellent.

Further, the output shaft 46a of the direction changing portion and the axle 25
The height H1 between them is relatively higher than the height H2 shown in FIG. 7B according to the present invention (H1> H2), and the difference between them is H1-
The present invention can lower the body weight of the vehicle by H2 minutes.

Further, in the hypothetical example, a space having a height of H3 is required in front of the direction changing gear box 46a, and the mounting position of the headlight or the carrier is increased by this amount, or the height is made the same. Although it is necessary to reduce these as they are, the present invention solves such a problem.

In addition, since the output shaft 46 of the direction changing portion overlaps with the front fork 2 in a side view, this portion is hardly visible and the appearance is refreshing.

FIG. 6 shows a modified example in which lowering the drive shaft position is prioritized. The direction changing portion intermediate shaft 43, the output shaft 46, gears and the like provided on these are positioned above the joint 22.

In this way, since the drive shaft 21 can be lowered as much as possible, even if the joint 22 moves upward, the vehicle body center of gravity can be maintained at the same level as a whole, and the drive shaft 21 above the lowered drive shaft 21 can be maintained. Since the space 53 is expanded downward, it is easy to pass the foot when getting on and off, and it is possible to easily get on and off.

The present invention can be modified in various ways. For example, instead of the chain 24, a transmission system by belt drive or gear train drive may be used. Further, it can be applied to a three-wheeled motor vehicle.

[0039]

According to the first aspect of the present invention, the direction changing gear box has a direction changing section input shaft having an axis orthogonal to the axis of the head pipe, and the direction changing section input shaft is vertically stacked.
Is provided with a direction changing portion intermediate shaft that extends parallel to the front-rear direction and a direction changing portion output shaft that extends to one side in the vehicle width direction orthogonal to the rear end of the direction changing portion intermediate shaft. The input shaft of the direction changing portion and the intermediate shaft of the direction changing portion are arranged below the head pipe and near the axis.

Therefore, it is possible to reduce the amount of the direction change gear box projecting forward of the head pipe, and as a result,
The steering moment of inertia is reduced to enable light handling.

In addition, the relatively heavy direction changing gearbox is lowered rearward as compared with the conventional case, and is located closer to the center of gravity of the vehicle, so that the front-rear weight balance is also excellent.

Further, since the direction changing gear box does not press the space in front of the head pipe so much, the mounting position of the headlight and the carrier can be lowered and the weight of the vehicle can be lowered. If the mounting position is not lowered, the size of mounting parts such as headlights and carriers can be increased.

According to a second aspect of the present invention, in the invention of the first aspect, a main rotating member is provided on the output shaft of the direction changing portion, and a winding transmission member for driving front wheels is wound around the main rotating member, and the main rotating member is provided on the side surface. It was placed at a position overlapping the front fork when viewed.

Therefore, most of the members constituting the direction changing mechanism, such as the output shaft of the direction changing section, can be made to be hardly visible, and the appearance can be improved.

[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 wheel 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 diagram showing an action.

FIG. 6 shows a modified example.

[Explanation of symbols]

1: front wheel, 2: front fork, 5: direction change gear box, 10: head pipe, 21: drive shaft, 22: joint, 23: direction change gear train 23, 4
6: Output shaft of direction changing part, ST: Steering axis

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62M 17/00 B60K 17/34 B62K 11/00 B62K 21/18

Claims (2)

(57) [Claims] 1. A drive shaft provided in the front-rear direction of a vehicle body is connected by a joint to a direction-changing gear box provided in front of a front fork, and the direction-changing gear box changes the power transmission direction from the front-rear direction to the up-down direction. In a front-wheel drive device for a two- and three-wheeled vehicle that drives front wheels, a direction-changing gearbox includes a direction-changing portion input shaft having an axis orthogonal to the axis of the head pipe, and the direction-changing portion input shaft and a vertical direction. A direction changing part intermediate shaft that overlaps and extends parallel to the front-rear direction and a direction changing part output shaft that extends to one side in the vehicle width direction orthogonal to the rear end of the direction changing part intermediate shaft are provided. Direction changing section output shaft and direction changing section input shaft
A front-wheel drive device for a two-wheeled motorcycle, characterized in that an intermediate shaft and a direction changing part intermediate shaft are arranged below the head pipe and near the axis. 2. A driving rotation member is provided on the output shaft of the direction changing portion,
The front wheel of the motorcycle of claim 2, wherein a winding transmission member for driving the front wheels is wound around the winding member, and the driving rotation member is disposed at a position overlapping the front fork in a side view. Drive.