JPH0239667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a transmission case device for a swing type power unit for a motorcycle.

Conventional technology In swing type power units for motorcycles,
When transmitting the output of the engine located in the front to the rear wheels, since there is a relatively large distance between the engine output shaft and the rear wheel axle, it is preferable to use a V-belt device, and the engine output shaft Since it rotates at high speed, it is necessary to equip it with a reduction gear device.
There is something described in the No.

In the power unit described in the above publication, the engine crankcase is divided into left and right parts along the front and rear vertical planes near the cylinder center axis, and the crankcase located on the left side of the vehicle body is formed integrally with the transmission case body of the power unit. The rear end portion of the transmission case body is formed at each right-hand pivot portion of the rear axle integrated with the rear wheel and the intermediate shaft of the reduction gear device, and serves as the left-hand pivot portion of the rear axle and the intermediate shaft. The transmission cover is attached to the recessed portion of the transmission case body from the left side of the transmission case body, and a V-belt cover that covers the V-belt device is further attached to the left side of the transmission case body.

Problems to be Solved In the conventional power unit disclosed in the above publication, the transmission cover is attached from the left side so as to seal the rear left opening of the transmission case body, and the V-belt cover is further attached to the left side.
When servicing the reduction gear or inspecting the rear axle pivot, be sure to
After removing the belt cover and attaching the transmission cover, the V-belt cover had to be attached, which required a lot of effort and time to maintain and inspect the reduction gear device and the rear axle.

In addition, at the rear of the transmission case body, in addition to the intermediate shaft of the reduction gear device and the pivot portion of the rear axle, a seal structure surrounding the drum opening of the rear wheel and a structure equipped with parts of the rear wheel braking means are formed. In addition, the mold for the transmission case body has become larger and has a complicated shape over its entire length, which inevitably increases the molding cost.

Means and Effects for Solving the Problems The present invention relates to an improvement of a transmission case device for a motorcycle that overcomes the above-mentioned difficulties. A recess is formed on the side surface of the rear wheel in the extending transmission case main body, a reduction gear device comprising an input shaft and an axle is disposed within the recess, and a transmission cover is fluid-tightly attached to the recess from the rear wheel side. A V-belt is stretched between a pulley on the input shaft and a pulley on the engine output shaft, which are located on the opposite side of the transmission cover with the transmission case main body in between.
The present invention is characterized in that a V-belt cover constituting a belt device and covering the V-belt device is attached to the transmission case main body from the side opposite to the rear wheel.

Since the present invention is configured as described above,
When servicing the reduction gear device or inspecting the pivot portion of the rear axle, it is only necessary to remove the transmission cover without removing the V-belt cover. The effort and time required for maintenance and inspection can be greatly reduced.

Further, in the present invention, there is no need to form a seal surrounding the rear wheel drum opening or a structure for mounting parts of the rear wheel braking means on the transmission case body.
It is possible to suppress the enlargement of the mold for the transmission case main body as much as possible, and also to simplify the shape of the rear part of the mold, thereby reducing mold forming costs.

Embodiment Hereinafter, an embodiment of the present invention illustrated in FIGS. 1 to 5 will be described.

Power unit 2 of scooter type motorcycle 1
In this case, the engine E and the transmission case 3 are integrally constructed. The transmission case 3 extends from the side of the engine E to the side of the rear wheel RW to form a rear frame.

The transmission case 3 includes a case body 4, a V-belt cover 5 that covers the outside of the vehicle body, and a transmission cover 6 that defines a rear transmission chamber together with the case body 4.

Further, inside the transmission case 3, a crankshaft 7, an intermediate shaft 8 of a kick starting device, a kick shaft 9, an input shaft 10 of a reduction gear device, an intermediate shaft 11, and an axle 12 are arranged in order from the front. The axle 12 passes through the transmission cover 6, and a wheel is attached to the end of the axle.
RW is fitted. A variable pulley 13 is disposed at one end of the crankshaft 7, and a V-belt 15 is stretched across the variable pulley 13 and a variable pulley 14 on the input shaft 10 located at the rear. Also, on the input shaft 10, an automatic centrifugal starting clutch 1 is located outside the variable pulley 14.
6 are arranged.

On the other hand, a concave wall 4a is formed at the rear of the case body 4 on the side where the rear wheels are disposed, and a mission cover 6 having a substantially U-shaped cross section is fluid-tightly fitted into the concave wall 4a. A reduction gear device 21 is disposed within a mission chamber 20 defined by a concave wall 4a and a mission cover 6. As shown in FIG.

This reduction gear device 21 includes an input shaft 1 that is pivotally supported across a case body 4 and a transmission cover 6.
0, an intermediate shaft 11 and gears 22, 23, 24, 25 fitted onto the axle 12. Further, the axle 12 passes through the transmission cover 6,
It is pivotally supported by the transmission cover 6 and the case body 4, and a rear wheel RW is integrally fitted to the axle 12.

In the above configuration, when the crankshaft 9 is rotated, the intermediate shaft 8 rotates due to the meshing relationship between the fan-shaped gear 9a and the gear 8a on the intermediate shaft 8, and the gear 8b and the crankshaft 7 slide on the shaft. upper gear 7a
are engaged, the crankshaft 7 is rotated, and the engine E is started. While the rotational speed of the engine E is low, the power transmitted to the rear variable pulley 14 via the variable pulley 13 and the V-belt 15 is not transmitted to the input shaft 10, but when the rotational speed increases, automatic centrifugal starting starts. The clutch 16 is connected and the input shaft 10 rotates. This rotation is reduced by the reduction gear device 21 and transmitted to the axle 12, causing the rear wheel RW to rotate. When the rotation of the engine E further increases, the variable pieces 13a and 14a of the variable pulleys 13 and 14 move toward the engine side and the centrifugal clutch side, and their effective pulley diameters change to expand and contract, respectively. moves to the front. Therefore, both pulleys 13,
The reduction ratio between 14 and 14 becomes smaller, resulting in an increased speed state.

By the way, the structural feature of this embodiment is that the transmission cover 6 is placed close to the rear wheel with respect to the case body 4.
Although it is located on the RW side, it is necessary to remove the oil-tight transmission cover 6 and remove the reduction gear device 21.
When performing maintenance, there is no need to remove the variable pulley 14 or the self-extending centrifugal starting clutch 16, resulting in good maintainability.

Furthermore, tighten the mounting bolts of the mission cover 6 to
Since everything is provided outside the belt cover 5, there is no need to remove the V-belt cover 5.

The attachment relationship of the mission cover 6 to the case body 4 may be structured as shown in FIG. 6. In the figure, 34 indicates the case body, and 36
indicate the mission covers, respectively.

Next, the embodiment shown in FIG. 7 will be described.

In the figure, 64 is the case body;
A transmission cover 66 is fluid-tightly fitted into the concave portion on the rear wheel side, an axle 72 is pivotally supported across the transmission cover 66 and the case body 64, and an input shaft 70 is coaxially supported with the axle 72. Case body 64
and a V-belt cover 65. An input shaft cylinder 70a is rotatably fitted onto the shaft 70, and a variable driven pulley 74 is disposed on the input shaft cylinder 70a.An automatic centrifugal starting clutch 76 is mounted on one end of the input shaft cylinder 70a. A clutch center 76a is integrally provided, and a corresponding clutch outer 76b is fitted onto the input shaft 70. Further, an intermediate shaft 71 is pivotally supported across the mission cover 66 and the case body 64, and the shaft 70,
Gears 82, 83 on intermediate shaft 71 and axle 72,
Reduction gear device 81 composed of 84 and 85
is housed in the mission chamber 80.

In the above configuration, when the rotational speed of the variable pulley 74, which rotates in conjunction with the variable pulley on the crankshaft, increases beyond a certain value, the automatic centrifugal starting clutch 76 becomes connected, and the reduction gear device 8
1, the engine output is transmitted to the axle 72.

The attachment structure of the mission cover 66 in this embodiment is also substantially the same as that shown in FIGS. 1 to 5, and is rigidly held by the case body 64.

[Brief explanation of drawings]

FIG. 1 shows a side view of a motorcycle equipped with a transmission case device according to an embodiment of the present invention, FIG. 2 shows a cross-sectional plane of the transmission case device, and FIG. A cutaway side view of the main visual part, Figure 4 is the 2nd
FIG. 5 is a side view of the main part as seen from the line arrow in FIG. 4, FIG. The figure is a cross-sectional plan view of a main part of a transmission case device according to still another embodiment. 1...Motorcycle, 2...Power unit, 3
...Transmission case, 4...Case body, 4a...Concave wall, 5...V belt cover, 6...Mission cover, 7...Crankshaft, 8...Intermediate shaft, 9
...Kick shaft, 10...Input shaft, 11...Intermediate shaft, 12...Axle, 13, 14...Variable pulley, 13a, 14a...Movable piece, 15...V belt, 16...Automatic centrifugal type Starting clutch, 20...
Mission chamber, 21... Reduction gear device, 22, 2
3, 24, 25...gear, 34...case body,
36...Mission cover, 64...Case body, 65...V belt cover, 66...Mission cover, 70...Input shaft, 70a...Input shaft cylinder, 71...Intermediate shaft, 72...Axle , 80...Mission chamber, 81...Reduction gear device, 82,8
3, 84, 85...gear.

Claims (1)

[Claims] 1. A recess is formed on the side surface of the rear wheel in the transmission case body that extends from the side surface of the engine located at the front to the side surface of the rear wheel located at the rear, and a reduction gear device consisting of an input shaft and an axle is disposed within the recess. A transmission cover is fluid-tightly attached to the recess from the rear wheel side, and a pulley on the input shaft and a pulley on the engine output shaft are located on the opposite side of the transmission case body from the transmission cover. A swing-type power unit for a motorcycle, characterized in that a V-belt is spanned to constitute a V-belt device, and a V-belt cover that covers the V-belt device is attached to the transmission case main body from the side opposite to the rear wheel. transmission case equipment.