JPS629060A - Vibration isolating construction for belt of belt transmission type stepless transmission - Google Patents

Abstract

PURPOSE:To improve the durability of a belt by suppressing the flapping vibration of said belt in both up and down and right and left directions, and suppressing an internal heat generation due to the bending of said V-belt. CONSTITUTION:A guide roller 33 is provided so as to be brought into contact with the inner peripheral surface of a V-belt, on a line connecting the centers of both pulleys, near points at which a belt line 31 intersects a belt line 32. Thereby, a contact between the V-belt and a guide roller 33 can be kept properly at all times regardless of variation in velocity ratio. Accordingly, the flapping vibration of the V-belt can be suppressed by providing the guide roller, efficiently suppressing a heat generation due to the internal stress of the belt.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a continuously variable transmission mainly used in a drive device of a motorcycle, and in particular to a belt having a guide means that can effectively suppress vibration of the belt. This invention relates to a belt vibration isolation structure for a continuously variable transmission.

<Prior Art> Continuously variable transmissions using belt transmission, which can vary the pitch circle radius of the drive and driven pulleys by utilizing centrifugal force or the like, have conventionally been used as driving force transmission devices for motorcycles.

<Problems to be Solved by the Invention> In this type of belt transmission device, the temperature of the belt increases due to heat generation due to friction between the belt and the pulley, resulting in loss of durability of the belt due to thermal fatigue. It's inconvenient. Regarding belt temperature rise, not only friction heat generation mentioned above but also
Heat generation is also caused by the internal friction of the belt structure itself due to belt bending and waving.In any case, in order to suppress belt temperature rise as much as possible, it is necessary to suppress belt vibration and eliminate unnecessary internal stress in the belt structure. It is preferable not to generate.

The present invention was made in view of such knowledge, and its main purpose is to provide a belt vibration isolation structure for a belt-driven continuously variable transmission having a guide means that can effectively suppress belt vibration. There is a particular thing.

<Means for Solving the Problems> According to the present invention, this object is to provide a belt transmission system consisting of a variable diameter drive pulley, a driven pulley, and a V-belt suspended between these pulleys. A belt vibration isolation structure for a continuously variable transmission, which is located on a line connecting the centers of the drive pulley and the driven pulley, and viewed from the side of each belt line at the maximum speed ratio and the minimum speed ratio. a rotation center located in the vicinity of the intersection point and supported so as to be slidable and rotatable in the axial direction; and an outer circumferential surface adjacent to the inner circumferential surface of the V-belt and having a circumferential groove capable of receiving the V-belt. This is achieved by providing a belt vibration isolation structure for a belt-driven continuously variable transmission characterized by having a guide roller having the following characteristics.

<Function> In this way, the wave motion of the belt in the vertical direction is suppressed by the idle roller, and therefore heat generation due to unnecessary internal stress is minimized, resulting in improved belt durability. It is possible. Furthermore, by receiving the V-belt in the annular groove, it is possible to suppress not only vertical shooting but also horizontal shooting.

Embodiments The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 shows a drive device for, for example, a scooter to which the present invention is applied, in which a drive pulley 2 is attached to the crankshaft of an air-cooled gasoline engine 1, and the rotation of the engine 1 is controlled by a V-belt 3. is transmitted to the driven pulley 4 via.

The rotation of the driven pulley 4 is transmitted to a plurality of gears in a reducer 6 via a centrifugal clutch 5, and after being decelerated by the meshing of these gears, it is transmitted to a rear wheel 7 fixed to a drive shaft. . These drive devices are entirely covered with a cover 8 to prevent dust and raindrops from entering the drive devices.

FIG. 2 shows the main parts of the above-mentioned drive device.

A crankshaft 12 connected to the large end of the connecting rod 11 is rotatably supported by the engine body 1, and a drive pulley 2 is attached to one end of the crankshaft 12. The drive pulley 2 includes a fixed drive pulley half 13 fixed to the shaft end of the crankshaft 12, and a fixed drive pulley half 13 fixed to the shaft end of the crankshaft 12.
The movable drive pulley half 14 is slidably supported in the axial direction relative to the engine 1, and when the rotational speed of the engine 1 increases, the movable drive pulley half 14 moves radially outward due to centrifugal force. The roller weight 15 allows it to be pushed axially towards the fixed drive pulley half 14 . Therefore, the width of the groove formed by both drive pulley halves 13 and 14 is variable depending on the rotational speed of the engine.
When the rotational speed increases, the V-belt 3 is pushed up toward the outer circumference of the drive pulley 2, and as a result, the pitch circle radius is increased.

A fan blade 13a whose outer peripheral side is curved and extends in the radial direction is provided on the outer surface of the fixed drive pulley half 13 over the entire circumference. Outside air can be drawn into the cover 8.

The driven pulley 4 to which the rotational force of the engine 1 is transmitted through the V-belt 3 is a fixed driven pulley half 16.
and a movable driven pulley half 17, the fixed driven pulley half 16 is fixed to a hollow shaft 19 that is rotatably supported relative to the pulley shaft 18, and the movable driven pulley half 17 has an axis line on the outer peripheral surface of the hollow shaft 19. It is supported so as to be slidable in the direction. Further, this movable driven pulley half 17 is biased toward the fixed driven pulley half 16 by the coil spring 22, and at low speeds, both driven pulley halves 16 and 17
The groove width formed by (1) is made to be the narrowest.

The pulley shaft 18 and the hollow shaft 19 are connected via the centrifugal clutch 5, and when the hollow shaft 19 to which the fixed driven pulley half 16 is fixed exceeds a predetermined rotation speed, the pulley shaft 18
The centrifugal clutch 5 is connected so that the shaft 19 and the hollow shaft 19 can rotate together, and the driving force of the engine 1 is transmitted to the pulley shaft 18.

Further, the fixed driven pulley half 16 and the movable driven pulley half 17 are connected by a torque cam mechanism (not shown), so that the pulley pitch circle radius can be automatically changed in accordance with running resistance.

The pulley shaft 18 meshes with a plurality of gears provided inside the reducer 6 and is connected to the drive shaft 21, and as described above, the tire 7 fixed to the drive shaft 21 is driven. .

A guide roller 33 contacts the inner peripheral surface of the V-belt 3 on a line connecting the centers of both pulleys near the intersection of the belt line 31 at the maximum speed ratio and the belt line 32 at the minimum speed ratio. (Fig. 3).

By doing so, proper contact between the V-belt 3 and the guide roller 33 is always maintained regardless of changes in the speed ratio.

The guide roller 33 has an annular groove 33 to receive the V-belt 3.
A fixed shaft 3 is fixed to a bracket screwed onto a boss 34 provided upright on the drive device casing.
5 and is rotatably supported. The fixed shaft 35 has a sliding shaft 36 spline-fitted to each other on its outer peripheral surface, and the guide roller 33 described above is supported on the outer peripheral surface of the sliding shaft 36 via a ball bearing 37.

Further, the sliding shaft 36 is always urged toward the center of the vehicle body by a coil spring 38 fitted into the spline portion of the fixed shaft 35. In this way, the guide roller 33 can rotate while sliding in the axial direction, and can therefore follow the displacement of the V-belt 3 due to changes in the pitch circle radius of both pulleys 2.4. be.

Since the tension of the V-belt 3 changes due to changes in the driving force,
In a vehicle transmission device where the speed and driving force constantly change, waving vibrations of the V-belt 3 tend to occur relatively large. However, by providing the above-mentioned guide roller, it is possible to suppress such vibrations.
Heat generation due to internal stress of the belt can be effectively suppressed.

<Effects of the Invention> As described above, according to the present invention, since it is possible to effectively suppress the undulating vibration of the V-belt in both the vertical and horizontal directions, it is possible to suppress internal heat generation due to unnecessary bending of the V-belt. This can have a great effect on improving the durability of the belt.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a drive system for a motorcycle to which the present invention is applied. FIG. 2 is a partially cutaway top view of the belt-driven continuously variable transmission according to the present invention. FIG. 3 is a side view showing the relationship between the pulley and the belt. 1...Engine 2...Drive pulley 3.
...V-belt 4...Driven pulley 5...
Centrifugal clutch 6...Reducer 7...Rear wheel
8...Cover 8a...Outside air intake port 11...
・Connecting rod 12...Crankshaft 13...Fixed drive pulley half 13a...Fan blade 14...Movable drive pulley half 15...Roller weight

Claims (1)

[Scope of Claims] A belt vibration isolation structure for a belt transmission type continuously variable transmission comprising a variable diameter drive pulley, a driven pulley, and a V-belt suspended between these pulleys, the drive pulley and The belt line is located on a line connecting the centers of the driven pulleys and near the intersection of each belt line when viewed from the side at the maximum speed ratio and the minimum speed ratio, and is supported so as to be slidable and rotatable in the axial direction. A belt-driven continuously variable transmission comprising a guide roller having a center of rotation, a circumferential groove capable of receiving the V-belt, and an outer circumferential surface adjacent to the inner circumferential surface of the V-belt. Belt anti-vibration structure.