JPH0444136B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable V-pulley continuously variable transmission.

[Conventional technology]

A variable V-pulley continuously variable transmission has a pair of V-pulleys around which an endless V-belt is stretched.
At least one of them uses a variable V pulley that can steplessly change the diameter of the V belt,
The variable speed is changed steplessly by changing the diameter of the V-belt wrapped around the variable V pulley, and since stepless speed change can be achieved with a relatively simple structure,
As described in Japanese Patent No. 58-137663, it is extremely effective as a transmission for motorcycles with low engine output.

FIG. 1 shows a conventional example of such a variable V-pulley type continuously variable transmission.

This continuously variable transmission uses variable V pulleys 1 and 2 on both the input and output sides in order to widen the setting range of the gear ratio. V-belt 3 is stretched across it.

As shown in FIGS. 2 and 3, this chain type V-belt 3 connects two types of link plates 4 and 5 with a connecting pin 6 and a bush 7 in an endless manner like a chain. Each ring plate 4, 5 is provided with drive blocks 8, 9 that engage with the V grooves of each pulley 1, 2, and these drive blocks 8, 9 provide a function as a V belt.

As shown in FIG. 4, the variable pulleys 1 and 2 face a fixed-side V-groove structure plate B fixed to the shaft A, and this fixed-side V-groove structure plate B, and the fixed-side V-groove structure plate B. A movable side V-groove structure board D that is movable only in the axial direction with respect to the board B and cooperates with the fixed side V-groove structure board B to form the V-groove C, and this movable side V-groove structure board The structure includes a biasing means (not shown) that biases D toward the stationary side V-groove configuration board B to generate a frictional force between the V-groove C and the V-belt 3, and By moving the movable V-groove configuration board D in the axial direction, the diameter of the V-belt 3 around which it is wound is changed.
The inclined surfaces E and F of the V-groove constituent plates B and D forming the V-groove C are finished substantially uniformly over the entire area and are given a predetermined coefficient of friction.

[Problem that the invention seeks to solve]

The aforementioned variable V pulleys 1 and 2 generate a frictional force between the V-groove C and the V-belt 3 by the urging means that urges the movable side V-groove structure plate D, and this frictional force causes From V pulley 1 to V belt 3, and then V
Power is transmitted sequentially from the belt 3 to the V-pulley 2, but when the diameter of the V-belt 3 changes and the gear ratio changes, the power is transmitted sequentially from the belt 3 to the V-pulley 2. Since the contact area between the V-groove C and the V-belt 3 also increases or decreases, if a simple elastic member is used as the biasing means so that the force for biasing the movable side V-groove component plate D is approximately constant, the power An inconvenient problem arises because the frictional force itself related to transmission increases or decreases as the gear ratio changes.

For example, when the V-pulley 1 on the input side has to transmit a large torque, the diameter of the V-belt 3 is reduced to increase the gear ratio. Therefore, the contact area between the V-groove C and the V-belt 3 becomes smaller, and as a result, the frictional force generated between the V-belt 3 and the V-groove C becomes relatively smaller than before, resulting in the maximum allowable transmission. A problem arises in that the torque decreases.

This invention was proposed to solve such problems, and uses a simple elastic member with a substantially constant biasing force as a biasing means for biasing the movable V-groove plate of the variable V pulley. To obtain a variable V-pulley type continuously variable transmission in which the frictional force between a V-belt and a V-groove related to power transmission does not increase or decrease with a change in the gear ratio even when used, that is, To provide a variable V-pulley type continuously variable transmission capable of maintaining high allowable transmission torque over the entire speed change range and requiring inexpensive parts.

[Means for solving problems]

In the variable V-pulley type continuously variable transmission of the present invention, as a means to solve the above-mentioned problem, each of the V-groove configuration plates on the fixed side and the movable side constituting the variable V-pulley is
The friction coefficient of the sloped surface forming the V-groove was increased as the diameter of the sloped surface became smaller.

[Effect]

In this way, if the friction coefficient of the sloped surface forming the V-groove is increased as the diameter of the sloped surface becomes smaller, the diameter around which the V-belt wraps becomes smaller, and the contact area between the V-belt and the V-groove decreases. Even if the frictional force decreases due to the reduction in the contact area, it can be compensated for by the increased frictional force due to the increased friction coefficient. Therefore, even if a simple resilient member with a substantially constant biasing force is used as a biasing means for biasing the movable side V-groove configuration plate of the variable V pulley, the gap between the V-belt and the V-groove This eliminates the problem that the frictional force generated in the transmission increases or decreases as the gear ratio changes.

〔Example〕

FIG. 5 is a sectional view of the main parts of a scooter type motorcycle to which the present invention is applied.

In the figure, 10 is an engine, 11 is a case, and a final shaft 13 serving as a rotation axis of a rear wheel 12 is supported at the rear of the case 11.

The case 11 has a transmission chamber 14 on the engine 10 side.
A reduction gear chamber 15 is defined on the final shaft 13 side. A continuously variable transmission 16 according to the present invention is housed in the transmission chamber 14, and a driven shaft 18 which receives rotational force from the continuously variable transmission 16 via a clutch mechanism 17 and the shaft are installed in the reduction gear chamber 15. Gears 19, 20, and 21 for transmitting the rotation of 18 to the final shaft 13 are installed inside.

The continuously variable transmission 16 uses the crankshaft 10a of the engine 10 as an input shaft, and has a cylindrical driven face boss 24 rotatably fitted onto the driven shaft 18 via pairings 22 and 23. As an output shaft, a variable V pulley 25 is provided on both the input shaft (crankshaft 10a) and the output shaft (driven face boss 24).
26, and an endless chain type V belt 3 is stretched around these variable V pulleys 25, 26, which is the so-called variable V pulley type.
The rotational force of the driven face boss 24 is transmitted to the dribble face boss 24, and the rotational force of the driven face boss 24 is transmitted to the driven shaft 18 via the clutch outer 17a of the clutch mechanism 17.

As described above, each of the variable V pulleys 25 and 26 is connected to the fixed side V groove configuration board 2 fixed to the shaft.
5a, 26a, and the fixed side V-groove configuration board 25a, 2
A movable side V-groove structure board 2 is provided coaxially with the fixed side V-groove structure board 25a, 6a, and is supported movably only in the axial direction with respect to the fixed side V-groove structure boards 25a, 26a.
5b and 26b, and the V-groove 25 around which the V-belt 3 is wound is provided by both of these V-groove configuration boards.
c, 26c are formed.

Each of the variable V pulleys 25 and 26 biases the respective movable side V-groove configuration plates 25b and 26b toward the fixed side V-groove configuration plates 25a and 26a, and the V-groove 25c,
26c and the V-belt 3 are provided with biasing means 27 and 28 for generating a frictional force.

The biasing means 27 of the variable V-pulley 25 is disposed behind the movable side V-groove structure plate 25a, and its movement in the axial direction is restrained, so that the biasing means 27 of the variable V-groove structure plate 25
A lamp plate 30 has a space 29 formed between it and the back surface of the crankshaft 10a, the width of which becomes narrower as the distance from the center of the axis of the crankshaft 10a increases. Weight roller 3 moves outward due to the centrifugal force generated
1, and when the weight roller 31 moves outward under centrifugal force, the centrifugal force urges the V-groove structure plate 25a to move the V-groove structure plate 25a to a balanced position.

The biasing means 28 of the variable V pulley 26 is a compression coil spring, and the compression coil spring 28 is in a compressed state between the clutch plate 32 fixed to the end of the driven face boss 24 and the movable V groove configuration plate 26b. V-groove configuration board 2 is attached with almost constant force.
6b is energized.

The variable V pulleys 25 and 26 described above improve the power transmission efficiency, so the V groove 25 and 26 each improve the power transmission efficiency.
The slopes of the V-groove plates that make up parts c and 26c have been carefully designed. This point will be explained using the variable pulley 26 as an example.

Each V groove configuration board 26a, 2 of the variable V pulley 26
6b, as shown in FIG. 6, the inclined surface S forming the V-groove 26c is provided by the welding layer 33.

This welding layer 33 is applied to each V-groove configuration board 26a, 26.
Fine metal pieces are welded onto base metals 26d and 26e of b, and are arranged so that the coefficient of friction increases as the diameter decreases by setting the size of the metal pieces.

In this way, if the coefficient of friction of the slope S forming the V-groove 26c is increased as the diameter of the slope S becomes smaller, the diameter around which the V-belt 3 is wound becomes smaller, and the V-belt 3 and the V-groove 26c are Even if the contact area is reduced, the reduced frictional force due to the reduced contact area can be compensated for by the increased frictional force due to the increased friction coefficient. Therefore, if a simple elastic member with a substantially constant urging force, such as the aforementioned compression coil spring, is used as the urging means 28 for urging the movable side V-groove configuration plate 26b of the variable V pulley 26, Also, the disadvantage that the frictional force generated between the V-belt 3 and the V-groove 26c increases or decreases as the gear ratio changes does not occur. Therefore, it is possible to maintain a high allowable transmission torque over the entire speed change range, and it is also possible to reduce costs by using cheaper parts.

In addition, in the above-mentioned example, although the slope S was entirely obtained by the welding layer 33, the structure of the slope S is not limited to this. For example, as shown in FIG.
4 and a second layer 35 on the smaller diameter side, the first layer 34 is made of welded metal pieces, and the second layer 35 is made of rubber or ceramic. It can also be constructed with a large number of layers. The inclined surface formed of a rubber material or ceramic is suitable when the portion contacting the V groove 26c is metal, as in the chain type V belt 3 of this embodiment.

〔Effect of the invention〕

As explained above, in the variable V-pulley type continuously variable transmission of the present invention, the coefficient of friction of the slope of each V-groove component plate that forms the V-groove is increased as the diameter of the slope becomes smaller. There is. Therefore, even if the diameter of the V-belt around which the V-belt wraps becomes smaller due to the movement of the movable V-groove configuration board and the contact area between the V-belt and the V-groove decreases, the frictional force that decreases due to this decrease in contact area will decrease. , the increased frictional force can be compensated for by the increased coefficient of friction. Therefore, the variable V
Even if a simple elastic member with a substantially constant biasing force is used as the biasing means for biasing the V-groove component plate on the movable side of the pulley, the frictional force generated between the V-belt and the V-groove The inconvenience of increasing or decreasing the speed change ratio as the gear ratio changes will no longer occur. In other words, it is now possible to maintain a high allowable transmission torque over the entire shift range, and also to reduce the cost of parts.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional variable V-pulley type continuously variable transmission, Figures 2 and 3 are enlarged views of the chain type V-belt used in Figure 1, and Figure 2 is an illustration of a conventional variable V-pulley type continuously variable transmission. 3 is a front view, FIG. 3 is a plan view, FIG. 4 is a sectional view of a conventional variable V pulley, FIG. 5 is a sectional view of the main parts of a motorcycle to which the present invention is applied, and FIG. FIG. 7 is an enlarged sectional view of the main parts of one embodiment, and FIG. 7 is an enlarged sectional view of the main parts of another embodiment of the present invention. 10a...Crankshaft, 16...Continuously variable transmission, 24...Driven face boss, 25,2
6...Variable V pulley, 25a, 26a...Fixed side V groove configuration board, 25b, 26b...Movable side V groove configuration board, 25c, 26c...V groove, 26d, 26e
... Base metal, 27, 28 ... Biasing means, S ... Inclined surface, 33 ... Welding layer, 34 ... First layer, 35 ...
...Second layer.

Claims (1)

[Claims] 1 comprising a pair of shafts serving as an input shaft and an output shaft, a pair of V pulleys attached to these shafts, and an endless V belt stretched across the V grooves of the pair of V pulleys, and At least one of the V pulleys has a fixed side V-groove structure plate fixed to the shaft, and a fixed side V-groove structure plate facing the fixed side V-groove structure plate and only in the axial direction with respect to the fixed side V-groove structure plate. a movable side V-groove configuration board that is movably provided and forms the V-groove in cooperation with a fixed side V-groove configuration board; and a movable side V-groove configuration board that is attached toward the fixed side V-groove configuration board. A variable V pulley is used, which includes a biasing means for generating friction between the V groove and the V belt.The variable V pulley is moved in the axial direction of the movable V groove configuration plate. In a variable V pulley type continuously variable transmission that obtains a desired gear ratio by changing the winding diameter of the V belt, the variable V
A variable pulley type continuously variable transmission characterized in that each V-groove forming plate of the pulley has a friction coefficient set to be larger as the diameter of the inclined surface forming the V-groove becomes smaller.