JPH08326859A - V-belt type continuously variable transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] Prevents roaring noise from the V-belt in the low speed range, and prevents deterioration of the V-belt due to frictional heat in the high-speed range.
Eliminates the need for particularly high rigidity. A V-belt type continuously variable transmission according to the present invention narrows a V-belt holding angle of a drive pulley 13 from an outer peripheral side toward an inner peripheral side, and a V-belt holding angle on the outer peripheral side is a V-belt.
On the other hand, the V-belt holding angle of the driven pulley 14 was widened from the outer peripheral side to the inner peripheral side while the V-belt holding angle of the driven pulley 14 was made closer to the V angle of the V-belt 15. For example, the V-belt holding angle on the outer peripheral side of the drive pulley 13 and the V-belt holding angle on the inner peripheral side of the driven pulley 14 are set to 30 °, and the V-belt holding angle on the inner peripheral side of the drive pulley 13 and the driven pulley 14 are set. The V-belt holding angle on the outer peripheral side is set to 28 °. The V angle of the V belt 15 is 30 °.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-belt type continuously variable transmission.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view of a V-belt type continuously variable transmission used as a transmission for, for example, a scooter type vehicle. This V-belt type continuously variable transmission 101 includes a drive pulley 103 mounted on a driving shaft (engine crankshaft) 102, a driven pulley 105 mounted on a driven shaft 104, and between these two pulleys 103, 105. It is composed of a wound V belt 106.

The drive pulley 103 is provided with a fixed drive face 107 that is provided so as to rotate integrally with the driving shaft 102, and a movable drive face 108 that is provided so as to rotate integrally with the driving shaft 102 and is movable in the axial direction. The driven pulley 105 is provided so as to rotate integrally with the driven shaft 104, and is provided so as to be rotatable integrally with the driven shaft 104 and movable in the axial direction, and is pressed toward the fixed driven face 109 side by the spring 110. It has a movable driven face 111.

As the rotation speed of the drive pulley 103 increases, the movable drive face 108 is fixed by the centrifugal force of the built-in weight roller 112.
And the V belt 106 is pushed out in the centrifugal direction to increase the V belt winding diameter d1 of the drive pulley 103.

On the other hand, on the driven pulley 105 side, the V belt
Since the 106 bites in the central direction and the V belt 106 moves the movable driven face 111 in the direction away from the fixed driven face 109 against the biasing force of the spring 110, the V belt winding diameter d2 of the driven pulley 105 is small. Become. Therefore, as the rotation speed of the driving shaft 102 increases, the rotation speed of the driven shaft 104 increases steplessly, and smooth gear shifting is performed.

By the way, as the V-belt 106, a cogged belt is generally used. This cogged belt is
As shown in FIG. 6, rack-shaped ridges 106a are provided at equal intervals on the inner peripheral portion thereof.

The V-belt holding angle α between the drive pulley 103 and the driven pulley 105 is slightly smaller than the V-angle β of the V-belt 106. For example, V-belt 106
Is set to 30 °, and the V belt holding angle α of both pulleys 103 and 105 is set to 28 °.

As a result, only the outer peripheral portion of the V-belt 106 (the hatched portion) comes into contact with both pulleys 103 and 105, and the side surface of the mountain portion 106a of the V-belt 106 is less likely to come into contact with the pulleys 103, 105, so that the howling noise is prevented. .

[0009]

However, as described above, the V belt holding angle α of the two pulleys 103 and 105 is set to the V belt 10 as described above.
If it is set smaller than V angle β of 6, V belt is always
Since only the outer peripheral part of 106 contacts both pulleys 103 and 105,
It is necessary to increase the strength and rigidity of the outer peripheral portion of the V belt 106.

Since the contact area between the pulleys 103 and 105 and the V-belt 106 is small, the V-belt 106 is particularly effective in the high speed range.
The frictional heat is hard to be radiated to both pulleys 103 and 105 side, and this frictional heat may deteriorate the V-belt 106.

The present invention has been made in order to solve the above problems, and it prevents the roaring noise from being generated from the V-belt in the low speed range, and prevents the V-belt from being deteriorated by frictional heat in the high speed range. An object of the present invention is to provide a V-belt type continuously variable transmission capable of preventing and also eliminating the need for particularly increasing the strength and rigidity of the V-belt outer peripheral portion.

[0012]

In order to achieve the above object, a V-belt type continuously variable transmission according to the present invention comprises a drive pulley mounted on a driving shaft side and a driven pulley mounted on a driven shaft. And the V wound between these two pulleys
A V-belt type continuously variable transmission including a belt and configured such that, as the rotational speed of the driving shaft increases, the V-belt winding diameter of the drive pulley increases and at the same time the V-belt winding diameter of the driven pulley decreases. , The V-belt holding angle of the drive pulley is narrowed from the outer peripheral side toward the inner peripheral side, and the V-belt holding angle of the outer peripheral side is made closer to the V-angle of the V-belt, while the V-belt holding angle of the driven pulley is changed from the outer peripheral side. It is characterized in that it is widened toward the inner peripheral side and the V-belt holding angle on the inner peripheral side is made closer to the V-angle of the V-belt.

[0013]

In this case, the V belt is wound around the inner circumference of the drive pulley and the outer circumference of the driven pulley in the low speed range. On the inner peripheral side of the drive pulley and the outer peripheral side of the driven pulley, since the V-belt holding angle is smaller than the V-angle of the V-belt, only the outer peripheral portion of the V-belt contacts the driven pulley and the drive pulley, The roaring noise is prevented.

In the high speed range, the V belt is wound around the outer circumference of the drive pulley and the inner circumference of the driven pulley. Since the V-belt holding angle between the outer peripheral side of the drive pulley and the inner peripheral side of the driven pulley is close to the V angle of the V-belt, the entire side surface of the V-belt contacts the driven pulley and the drive pulley. Therefore, the frictional heat of the V-belt is easily radiated to both pulleys, the deterioration of the V-belt due to the frictional heat is prevented, and it is not necessary to particularly increase the strength and rigidity of the outer peripheral portion of the V-belt.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a power unit of a scooter type vehicle. This power unit 1
Is provided with a single-cylinder engine 2 on its front head, and a V-belt continuously variable transmission 5 according to the present invention is provided inside a casing 4 connected to a crankcase 3 of the engine 2 and extending rearward. Equipment such as a reduction gear mechanism 6 and a centrifugal clutch mechanism 7 is built in, and the rear wheel 9 is supported by an axle 8 pivotally supported at the rearmost portion of the casing 4.

The crankshaft 10 of the engine 2 extends in the vehicle width direction inside the crankcase 3, and has a pair of left and right bearings 11L, 11
It is rotatably supported by R. This crankshaft 10
Is a drive shaft of the V-belt type continuously variable transmission 5.
On the other hand, a driven shaft 12 is supported in front of the axle 8, and this driven shaft 12 serves as a driven shaft of the V-belt type continuously variable transmission 5.

The V-belt type continuously variable transmission 5 includes a crankshaft.
A drive pulley 13 mounted on the shaft 10, a driven pulley 14 mounted on the driven shaft 12, and a V-belt 15 wound between these two pulleys.

By the way, an intermediate shaft 16 is supported between the driven shaft 12 and the axle 8, and these three shafts 8, 12, 16 are provided.
Each of the gears forming the reduction gear mechanism 6 is mounted on the shaft. Therefore, the rotation of the crankshaft 10 is further reduced by the reduction gear mechanism 6 after being changed by the V-belt type continuously variable transmission 5, and transmitted to the rear wheels via the axle 8.

As shown in FIG. 2, the drive pulley 13 includes a fixed drive face 18 provided integrally with the crankshaft 10 for rotation and a movable drive provided integrally with the crankshaft 10 for movement in the axial direction. It has a face 19 and. A slope plate 20 is provided inside the movable drive face 19, and a plurality of wedge-shaped roller chambers 21 narrowing toward the centrifugal direction are defined between the slope plate 20 and the movable drive face 19. Roller room 21
A cylindrical weight roller 22 is incorporated therein.

On the other hand, the drive pulley 13 has a fixed driven face 24 provided integrally with the driven shaft 12 via the centrifugal clutch mechanism 7, and a fixed driven face 24 provided integrally with the driven shaft 12 via the centrifugal clutch mechanism 7. The movable driven face 25 is provided so as to be movable in the axial direction, and the movable driven face 25 is pressed by the spring 26 toward the fixed driven face 24 side.

FIG. 2 shows the state of the V-belt type continuously variable transmission 5 in the low speed range. In this state, the movable driven face 25 of the driven pulley 14 moves the spring 26
Due to the urging force of the drive pulley 13, the driven pulley 14 has a larger V-belt winding diameter D2, and the drive pulley 13 has a smaller V-belt winding diameter D1. Therefore, the rotation speed of the crankshaft 10 is reduced and transmitted to the driven shaft 12.

FIG. 3 shows the state of the V-belt type continuously variable transmission 5 in the high speed range. As the rotation speed of the crankshaft 10 increases, the centrifugal force acting on the weight roller 22 built into the drive pulley 13 increases, and the weight roller 22 moves in the centrifugal direction to push and expand the roller chamber 21. 19 moves toward the fixed drive face 18, the V belt 15 is pushed out in the centrifugal direction, and the winding diameter D1 of the drive pulley 13 increases.

As a result, the V-belt is provided on the driven pulley 14 side.
Since 15 bites in the center direction and moves the movable driven face 25 in the direction away from the fixed driven face 24 against the biasing force of the spring 26, the winding diameter D2 of the driven pulley 14 becomes smaller. In this way, the rotational speed of the driven shaft 12 is continuously increased as the rotational speed of the crankshaft 10 increases, and a smooth gear shift operation is performed.

FIG. 4 shows an embodiment of the present invention.
(A) and (B) show the drive pulley 13 and the driven pulley 14, respectively. In the present invention, the V-belt holding angle of the drive pulley 13 is narrowed from the outer peripheral side toward the inner peripheral side,
The V-belt holding angle on the outer peripheral side is made closer to the V-angle of the V-belt 15, while the V-belt holding angle of the driven pulley 14 is widened from the outer circumferential side to the inner circumferential side, and the V-belt holding angle on the inner circumferential side is increased. It is close to the V angle of the V belt 15.

For example, in this embodiment, an angle changing line 27 is provided on the V belt contact surface of the drive pulley 13, and the V belt holding angle on the outer peripheral side of the angle changing line 27 is set to 30 °. The V-belt holding angle on the inner side of 27 is set to 28 °. The angle changing line 27 is provided substantially at the center in the radial direction of the belt contact surface of the drive pulley 13. The V angle of the V belt 15 is 30 °.

An angle changing line 28 is also provided on the V belt contact surface of the driven pulley 14, and the V belt holding angle on the outer peripheral side of the angle changing line 28 is set to 28 °.
The V-belt holding angle on the inner side of 28 is set to 30 °.

When the V-belt type continuously variable transmission 5 is constructed in this manner, the V-belt 15 drives the drive pulley 13 in the low speed range.
Is wound around the inner peripheral side and the outer peripheral side of the driven pulley 14. On the inner circumference side of the drive pulley 13 and the outer circumference side of the driven pulley 14, the V-belt holding angle is 28 °, and the V-belt 15 has a V-shape.
Since the angle is smaller than 30 °, only the outer peripheral portion of the V-belt 15 comes into contact with the driven pulley 14 and the drive pulley 13, and the roaring noise from the V-belt 15 is prevented.

In the high speed range, the V belt 15 is wound around the outer circumference of the drive pulley 13 and the inner circumference of the driven pulley 14. On the outer peripheral side of the drive pulley 13 and the inner peripheral side of the driven pulley 14, the V-belt holding angle is 30 °, and the V-belt 15
Is the same as the V angle, the entire side surface of the V belt 15 contacts the driven pulley 14 and the drive pulley 13. Therefore, the frictional heat of the V-belt 15 is easily radiated to the pulleys 13 and 14 side, the deterioration of the V-belt 15 due to the frictional heat is prevented, and the strength and rigidity of the outer peripheral portion of the V-belt 15 are particularly increased. There is no need.

In this embodiment, the V-belt holding angle of the drive pulley 13 and the driven pulley 14 is the angle changing line 27,2.
Although it is set in two stages with 8 as the boundary, angle change lines 27, 28
By adding more, the V belt wrap angle of both pulleys 13 and 14 can be set in multiple stages, and the belt contact surfaces of both pulleys 13 and 14 can be smoothly curved without providing angle change lines 27 and 28. The included angle may be changed steplessly.

[0030]

As described above, in the V-belt type continuously variable transmission according to the present invention, the V-belt holding angle of the drive pulley is narrowed from the outer peripheral side toward the inner peripheral side, and the V-belt on the outer peripheral side is formed. While making the included angle close to the V angle of the V belt, the V belt included angle of the driven pulley was widened from the outer peripheral side toward the inner peripheral side, and the V belt included angle on the inner peripheral side was made closer to the V angle of the V belt. It is characterized by that.

With this configuration, only the outer peripheral portion of the belt comes into contact with the driven pulley and the drive pulley in the low speed region, and the howling noise from the V belt is prevented. Also,
In the high speed range, the entire side surface of the belt comes into contact with the driven pulley and the drive pulley, so that the friction heat of the V belt is easily dissipated to both pulleys, the deterioration of the V belt due to the friction heat is prevented, and the outer peripheral portion of the V belt is prevented. Strength,
There is no need to increase rigidity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a power unit of a scooter type vehicle.

FIG. 2 is a cross-sectional view showing a state of a V-belt type continuously variable transmission in a low speed range.

FIG. 3 is a cross-sectional view showing a state of the V-belt type continuously variable transmission in a high speed range.

FIG. 4 shows an embodiment of the present invention, (A) is a diagram showing a drive pulley, and (B) is a diagram showing a driven pulley.

FIG. 5 is a cross-sectional view of a V-belt type continuously variable transmission showing a conventional technique.

FIG. 6 is a perspective view showing the structure of a V-belt.

[Explanation of symbols]

 5 V-belt type continuously variable transmission 10 Crankshaft which is the driving shaft 12 Driven shaft which is the driven shaft 13 Drive pulley 14 Driven pulley 15 V belt D1 V belt winding diameter of drive pulley D2 V belt winding diameter of driven pulley

Claims (1)

[Claims] 1. A drive pulley axially mounted on a driving shaft side, a driven pulley axially mounted on a driven shaft, and a V belt wound between these two pulleys. In the V-belt type continuously variable transmission configured such that the diameter of the drive belt wound around the V belt increases as it rises, and at the same time the diameter of the driven pulley wound around the V belt decreases. From the outer peripheral side toward the inner peripheral side, the outer peripheral side V belt holding angle is made closer to the V belt V angle, while the driven pulley V belt holding angle is widened from the outer peripheral side toward the inner peripheral side. A V-belt type continuously variable transmission characterized in that the V-belt sandwiching angle on the circumferential side is close to the V-angle of the V-belt.