JPH11230285A - Automatic transmission for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission for a motorcycle that allows an increase in the common ratio of its V belts and an increase in the banking angle even if a tire of a small diameter is used as in a motor scooter without affecting the design of an engine adversely. SOLUTION: An automatic transmission for motorcycle comprises a driving pulley 8 fitted on a crankshaft 4 in a motorcycle engine 1, a driven pulley 15 fitted on a driveshaft 6, an idle pulley 22 situated substantially right between the crankshaft 4 and driveshaft 6, and a first V belt 25 and a second V belt 26 looped among the driving pulley 8, driven pulley 15 and the idle pulley 22. This idle pulley 22 is made up of a pair of outer pulleys 23 fitted on an idle shaft 7 with an interval and an inner pulley 24 interposed between the paired outer pulleys 23 for sliding motion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission for a motorcycle mounted on a scooter or the like.

[0002]

2. Description of the Related Art A V-belt type automatic transmission having excellent lightness and low noise is attached to a scooter, a moped, or the like. In this automatic transmission (not shown), a V-belt common ratio (LOW / TOP) is set. To increase the diameter, it is common to increase the diameter of the drive pulley and the driven pulley. With this configuration, (1) the minimum diameter of the V-belt cannot be made small in consideration of the strength of the shaft and the surface pressure of the inner diameter of the movable drive face. (2) The reason is that the radius of the V-belt cannot be extremely reduced due to the durability of the V-belt. Therefore, conventionally, unless the pulley diameters of the drive pulley and the driven pulley are increased, the common ratio of the V-belt cannot be increased.

[0003] As a prior art document relating to this type of automatic transmission, there is JP-A-63-38746 and the like.

[0004]

However, when the pulley diameters of the drive pulley and the driven pulley are set to be large, the width of the crankcase and its cover increases up and down.
There was a problem that the design of the motorcycle was adversely affected. In the case of a small-diameter tire such as a scooter, there is a problem that the bank angle cannot be increased.

The present invention has been made in view of the above-mentioned conventional problems, and can increase the common ratio of a V-belt without adversely affecting the design of an engine. It is an object of the present invention to provide an automatic transmission for a motorcycle that can increase the vehicle speed.

[0006]

According to the present invention, in order to achieve the above object, a drive pulley attached to a crankshaft of a motorcycle engine, a driven pulley attached to the drive shaft, An idle pulley interposed between the crankshaft and the drive shaft; and a plurality of belts wound around the drive pulley, the driven pulley, and the idle pulley. It is characterized by comprising a pair of outer pulleys fitted at intervals and an inner pulley slidably interposed between the pair of outer pulleys. Note that a starting device may be provided between the drive pulley and the idle shaft.

Here, the "motorcycle" in the claims includes at least an on-road, a scooter, a family motorcycle, a moped, and the like. The “engine” includes a type such as a two-cylinder engine, a four-cylinder engine, a V-type engine, and a unit swing engine, but is not particularly limited. Further, the “plurality of belts” may be a two-stage hanger using two belts, or a multi-stage hanger of more than two. Therefore, the idle shaft and the idle pulley may be singular or plural. Further, the pair of outer pulleys constituting the idle pulley are fixedly attached to the idle shaft by means such as spline fitting, nut fastening, welding, or the like. Furthermore, "Inner pulley"
May be rotatable as long as it can slide in the direction of the idle axis, or may be spline-fitted or mounted in an intervening state by other known means.

According to the first aspect of the present invention, for example, in the case of two-stage hanging using two first and second belts, the motorcycle is wound around the drive pulley when idling or starting the motorcycle. The first belt rotates with a small turning radius, the inner pulley of the idle pulley is positioned inward of the vehicle body, the first belt wound on the idle pulley is pushed out, the turning radius increases, and the idle pulley rotates. The radius of rotation of the second belt wound on the pulley is reduced. In addition, the radius of rotation of the driven pulley increases.
This is because the spring force on the driven pulley side is larger than the force due to the centrifugal force of the rollers on the drive pulley side,
This is the state with the largest reduction ratio.

When the rotation speed of the engine increases, the centrifugal force of the roller increases, and when the spring force is overcome, the belt rotation radius of the drive side of the first belt increases,
The inner pulley on the idle side of the first belt gradually moves to the left, and the radius of rotation of the belt on the idle side of the first belt decreases. At the same time, the belt turning radius on the idle side of the second belt gradually increases, and the belt turning radius on the driven side of the second belt decreases. By such an operation, a wide belt common ratio from a low speed to a high speed can be achieved. This common ratio can be larger than that of a single belt.

According to the second aspect of the present invention, all or a part of the starting device can be installed in a space between the drive pulley and the idle shaft that has no particular use.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The automatic transmission of the motorcycle according to the present embodiment is a large scooter (for example, 250 cc,
An idle shaft 7 is interposed between the crankshaft 4 and the drive shaft 6 of the engine 1 of the motorcycle comprising
A drive pulley 8 is fitted to the crankshaft 4, a driven pulley 15 is fitted to the drive shaft 6, an idle pulley 22 is fitted to the idle shaft 7, and a first V is provided between the drive pulley 8 and the idle pulley 22. A belt 25 is wound around, a second V-belt 26 is wound between the idle pulley 22 and the driven pulley 15, and a kick starter 27 is interposed between the drive pulley 8 and the idle shaft 7. ing.

The engine 1 is of a unit swing type and includes a crankcase 2 in which a cylinder is mounted. A crankshaft 4 for supporting a connecting rod 3 is provided between a front part of the front part of the crankcase 2 and a bearing. It is rotatably mounted on the shaft. The side of the crankcase 2
An opening is formed, and a cover 5 is removably covered on the opening side via a fastener. Also, the drive shaft 6
The rear part of the crankcase 2 is rotatably supported via a bearing, and transmits power to a rear tire via an idle shaft and a rear axle shaft in a gear box (not shown). Also, the idle shaft 7 is configured to be short, and the crankcase 2
Is rotatably mounted via a bearing between a substantially central portion of the cover 5 and a cover 5, and is located substantially in the middle of the crankshaft 4 and the drive shaft 6.

The drive pulley 8 has a movable drive face 9 fitted slidably inside the crankshaft 4 via a spacer and a fixed drive face 10 fitted to the end of the crankshaft 4 in an opposed state. In preparation. The removable drive face 9 has an opposing surface formed in a tapered shape and an opposite opposing surface formed in an opening surface, and a plurality of weight rollers 11 move through a dish-shaped plate 12 at a predetermined interval inside. It is built in so that it can be rolled. Further, the fixed drive face 10 is formed in a dish shape in cross section, and a fan 13, a starter 14, a washer, and a
And nuts are mounted on top of each other.

The driven pulley 15 has a fixed driven face 16 fitted inside the drive shaft 6 via a bearing, and a movable driven face 17 fitted slidably on the end side of the drive shaft 6 via a spacer. Is provided in the facing state. A plurality of torque cam pins 18 are screw-projected from the peripheral surface of the fixed driven face 16 at predetermined intervals. In the movable driven face 17, a plurality of torque cams 19 fitted on the torque cam pins 18 on the peripheral surface are inclined in the circumferential direction and are cut out.
The cylindrical sheet 20 is fitted and covered.

A clutch shoe 21 is mounted on the movable driven face 17 at an end of a boss of the fixed driven face 16. Further, a spring 17a for controlling a shift is interposed between the movable driven face 17 and the clutch shoe 21. The spring 17a acts to bias the movable driven face 17 in the direction of the fixed driven face 16.

The idle pulley 22 includes a pair of left and right outer pulleys 2 fitted and mounted on the idle shaft 7 at intervals.
3 and an inner pulley 24 having a substantially abacus section in cross section, which is spline-fitted to the idle shaft 7 and positioned between the pair of outer pulleys 23. Each outer pulley 2
Reference numeral 3 is formed in a dish shape in cross section. Also, the inner pulley 24 functions to slide in the left-right direction of the idle shaft 7, in other words, in the axial direction. Further, the first and second V-belts 25 and 26 are formed endlessly using glass fiber or Kepler fiber having excellent heat resistance and abrasion resistance, and a plurality of teeth are arranged side by side on the inner peripheral surface. I have.

Further, the kick starter 27 includes a kick pedal 28 and a starter shaft 29 having the kick pedal 28 at an end. The starter shaft 29 is provided between the crankcase 2 and the cover 5 by a clip or bush. Is mounted on the shaft. A substantially fan-shaped drive gear 30 is fitted to the starter shaft 29 via a coil-shaped starter spring 31, and the drive gear 30 is meshed with a driven gear 32 that is supported by the cover 5 so as to protrude therefrom. Power is transmitted from 32 to the starter 14. A ratchet mechanism 33 is provided at an opposing portion between the driven gear 32 and the starter 14.

In the above configuration, when the kick pedal 28 is depressed, the drive gear 30 rotates the driven gear 32, and the driven gear 32 protrudes.
Is transmitted to the starter 14 and the crankshaft 4 rotates. When the engine 1 starts, the ratchet mechanism 33
Interrupts transmission to the driven gear 32.

According to the above configuration, a single V
Since the speed is changed smoothly using the first and second V-belts 25 and 26 instead of the belts, there is no need to set the pulley diameters of the drive pulley 8 and the driven pulley 15 to be large. Therefore, the gear ratio can be increased to approximately the square of the conventional gear ratio, and the gear width can be increased. In this regard, in recent years, large scooters have appeared, but with conventional automatic transmissions, it is not possible to increase the gear ratio and cannot expect improvement in performance. However, in this embodiment, a large gear ratio can be sufficiently obtained,
Performance such as speed of a large scooter can be remarkably improved.

Further, since the width of the crankcase 2 and its cover 5 does not expand vertically, there is no possibility that the design is adversely affected. Further, since there is no possibility of adversely affecting the design, shape, and the like, even if the tire such as a scooter has a small diameter, it is possible to increase the bank angle.

[0021]

As described above, according to the first aspect of the present invention, the V is reduced without adversely affecting the design of the engine.
There is an effect that the common ratio of the belt can be increased. Further, even in the case of a small-diameter tire such as a scooter, the bank angle can be increased. Furthermore, according to the second aspect of the present invention, since the starting device is installed in an unused space, it is not necessary to particularly provide a mounting space dedicated to the starting device in the engine, and the space can be effectively used.

[Brief description of the drawings]

FIG. 1 is a partial sectional explanatory view showing an embodiment of a motorcycle automatic transmission according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 engine 2 crankcase 4 crankshaft 5 cover 6 drive shaft 7 idle shaft 8 drive pulley 9 movable drive face 10 fixed drive face 11 weight roller 15 driven pulley 16 fixed driven face 17 movable driven face 17a spring 22 idle pulley 23 outer pulley 24 Inner pulley 25 First V-belt (belt) 26 Second V-belt (belt) 27 Kick starter (starter) 28 Kick pedal 29 Starter shaft 30 Drive gear 32 Driven gear 33 Ratchet mechanism

Claims (2)

[Claims] 1. A drive pulley attached to a crankshaft of a motorcycle engine, a driven pulley attached to the drive shaft, an idle pulley interposed between the crankshaft and the drive shaft, A plurality of belts wound around a pulley, a driven pulley, and an idle pulley, wherein the idle pulley has a pair of outer pulleys fitted at intervals on an idle shaft; An automatic transmission for a motorcycle, comprising an inner pulley interposed slidably on the automatic transmission. 2. An automatic transmission for a motorcycle according to claim 1, further comprising a starting device between said drive pulley and said idle shaft.