JPH01126466A - Continuously variable gear - Google Patents

Abstract

PURPOSE:To easily secure stable neutral state by providing the first and second bevel gears which are rotated in the opposite directions by rotary motion of a driven shaft and a driving shaft and controlling the rotation and stop of an output shaft according to a difference in relative rotational frequency therebetween. CONSTITUTION:When an operating lever 24 is located at a neutral position, the effective radii of the first and second driven pulleys 13, 14 and the first and second driving pulleys 6, 7 are at an intermediate value in a variable range, so that the rotation of a driving shaft 1 is transmitted as it is without change in speed to a driven shaft 1. Accordingly, the first bevel gear 27 connected to the driven shaft 1 and the second bevel gear 28 rotated through bevel gears 30-32 by the first driven pulley 13 are rotated in the reverse directions in the same rotational frequency. Accordingly, only the third bevel gear is rotated round a shaft 34, and an output gear 38 rotatably supporting the third bevel gear 33 is not rotated, so that an output shaft 3 connected to the output gear 38 through a gear 37 is not rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvement of a variable pulley type continuously variable transmission used in automobiles, agricultural machinery, etc.

(Prior Art) Conventionally, as a belt-type continuously variable transmission using belt transmission, a pair of input/output shafts arranged parallel to each other has been used, for example, as disclosed in Japanese Patent Application Laid-open No. 118159/1983. a fixed shave that is rotatably and non-slidably fixed to each of the input/output shafts, and a fixed shave that is opposed to each other so as to form a V-shaped belt groove between the fixed shaves on each shaft. A variable pulley consisting of a movable shaver and a movable shaver rotatably and slidably supported is provided, and a belt member is wound between the belt grooves of both variable pulleys to move the movable shaver of each variable pulley in the axial direction. It is well known that the gear ratio between the input and output shafts is changed by making the belt move toward and away from a fixed shaver and making the effective radius of the belt member wound around the belt groove between both shavers variable. There is.

(Problems to be Solved by the Invention) However, the above-mentioned conventional transmission is equipped with a planetary gear mechanism, and in the transmission equipped with this planetary gear mechanism,
It is generally difficult to achieve a neutral state in which the rotation of the output shaft is zero. For this reason, when actually installed in a vehicle, etc.,
There is a risk that the vehicle or the like may start moving even though it is in the neutral state, and the installation of a clutch or brake becomes necessary, which leads to the complexity of the device.

The present invention has been made in view of the above-mentioned problems, and its object is to change the rotation and rotation of the output shaft in relation to the movement of the movable shave of the variable pulley that changes the gear ratio between the input and output shafts.
By taking appropriate measures to control stopping, a large braking force can be generated in the neutral state, thereby easily ensuring a stable neutral state, and thus eliminating the need for clutches and brakes, making the device more compact. The goal is to try to make the world a better place.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides a drive shaft, a driven shaft, and an output shaft arranged parallel to each other. A pair of fixed shaves are disposed facing each other in the axial direction and are rotatably and non-slidably fixed to the drive shaft; There are provided two sets of first and second driving pulleys each consisting of one movable shaver having a shave surface for forming a belt groove between each fixed shaver. Further, a fixed shave is disposed on the driven shaft corresponding to the first drive pulley and is rotatably and non-slidably supported on the driven shaft, and the fixed shave is slidable and rotatably integral with the fixed shave. a first driven pulley comprising a movable shaver provided therein and having a shave surface for forming a belt groove between the movable shaver and the fixed shaver;
disposed on the driven shaft in correspondence with the second drive pulley;
A fixed shave that is rotatably and non-slidably fixed to a driven shaft, and a shave surface that is slidably and rotatably fixed to the fixed shave and that forms a belt groove between the fixed shave and the fixed shave. A second driven pulley is provided on the driven shaft. The movable shaves of each of the pulleys are moved toward and away from the opposing fixed shaves in order to change the gear ratio between the drive shaft and the output shaft, thereby changing the effective radius of each pulley. A belt is wound between the belt grooves of the first driving pulley and the first driven pulley, and between the belt grooves of the second driving pulley and the second driven pulley. Further, a first bevel gear is rotatably fixed to the driven shaft, and the first bevel gear is rotatably supported by the driven shaft opposite to the first bevel gear, and is rotationally driven by the first driven pulley in a direction opposite to the first bevel gear. a second bevel gear, and a first and second bevel gear.
A third bevel gear that meshes with the bevel gear, and a gear that is rotatably supported by the driven shaft between the first and second bevel gears and is rotationally fixed to the output shaft, and rotates the third bevel gear. A bevel gear mechanism is provided having a support output gear. By the bevel gear mechanism, when the first and second bevel gears rotate in opposite directions at the same rotation speed, the third bevel gear rotates in opposite directions.
While only the bevel gear is rotated and the rotation of the output gear is stopped, when the first and second bevel gears rotate in opposite directions to each other at different rotation speeds, the output gear is rotated together with the third bevel gear according to the difference in their relative rotation speeds. The output shaft is configured to be connected to rotate the output shaft.

(Function) With the above configuration, in the present invention, when changing the gear ratio between the drive shaft and the output shaft, the movable shave of the first driven knob is moved toward and away from the fixed shave. As a result, the effective radius of the first driven pulley is variably adjusted, while the movable shave of the first drive pulley of the drive shaft (common with the movable shave of the second drive pulley) is moved toward and away from the fixed shave, and 1 The effective radius of the drive pulley is variably adjusted.

By this movement of the movable shave toward and away from the movable shave, the movable shave of the second drive pulley (common to the movable shave of the first drive pulley) is moved toward and away from the fixed shave in a manner opposite to that of the first drive pulley. The effective radius of the drive pulley is variably adjusted. Furthermore, the movable shave of the second driven pulley is moved toward and away from the fixed shave in a manner opposite to that of the first driven pulley, and the effective radius of the second driven pulley is variably adjusted. That is, when the movable shave of the first driven pulley is brought closer to the fixed shave, for example, and the effective radius of the first driven pulley becomes smaller, the effective radius of the first driving pulley becomes larger. On the other hand, the effective radius of the second driving pulley becomes smaller, and therefore the effective radius of the second driven pulley becomes larger.

In this case, the first driven pulley is rotated at a low speed, and the second driven pulley is rotated at a high speed.

The rotation of the second driven pulley is caused by a first bevel gear rotatably fixed to the driven shaft, and the rotation of the first driven pulley is rotatably supported by a driven shaft opposite to the first bevel gear. and are transmitted to the second bevel gear which is rotationally driven in the opposite direction to the first bevel gear by the first driven pulley, so that the first and second bevel gears are caused to rotate in opposite directions to each other at different rotational speeds. As a result, the first
A third bevel gear that meshes with the second bevel gear is rotated, and an output gear that rotatably supports the third bevel gear is rotated by the difference in relative rotational speed between the first and second bevel gears. The output shaft drivingly connected to the output gear rotates in a direction opposite to the rotational direction of the drive shaft when the first bevel gear rotates at a higher speed than the second bevel gear, and when the output shaft rotates at a lower speed than the second bevel gear. are rotated at different speeds in the same direction as the rotational direction of the drive shaft.

On the other hand, when ensuring a neutral state, the first
The effective radius of both the second driven pulley and the first and second driving pulleys is set to be the same, and the first driven pulley and the second driven pulley are rotated at the same rotational speed. Therefore, the first bevel gear and the second bevel gear
The bevel gears are rotated in opposite directions at the same rotational speed, so that only the third bevel gear rotates, and the output gear rotatably supporting the third bevel gear does not rotate, thereby being drivingly connected to the output gear. The output shaft does not rotate.

In this way, for example, by moving the movable sheave of the first driven pulley toward and away from the fixed sheave, the rotation speed of the drive shaft can be changed to the driven shaft via the first drive pulley, the second drive pulley, and the second driven pulley. At the same time, the rotation and stopping of the output shaft is controlled by the difference in the relative rotational speed of the first and second bevel gears, which rotate in opposite directions due to the rotational movement of the driven shaft and the drive shaft. A large braking force is generated in the neutral state, thereby making it easy to maintain the neutral state, eliminating the need for a clutch or brake, and making the device more compact.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall configuration of a pulley-type continuously variable transmission according to an embodiment of the present invention, in which 1 is a drive shaft as an input shaft rotatably supported by a case (not shown) of the continuously variable transmission;
．． 3 are disposed below the drive shaft 1, and bearings 5, 5. A driven shaft and an output shaft are rotatably supported by..., and each of the drive shaft 1, driven shaft 2, and output shaft 3 is arranged parallel to each other in that order from above.

On the drive shaft 1, first and second drive pulleys 6.7 are disposed facing each other in the axial direction via a common boss portion 8, and the brush 1 and the second drive pulley 6.7 , a pair of flange-shaped fixed shaves 9 and 9' that are rotatably and non-slidably fixed to the drive shaft 1 by a key or the like, and both fixed shaves 9 and 9' that are opposite to each other. It consists of one abacus bead-shaped movable shaver 10 which is slidably and rotatably connected and supported by the common boss portion 8 of the shaver 9゜9'' by spline connection, and both fixed shavers 9, 9' and Between the movable shaver 10 and the movable shaver 10, belt grooves 11 and 11- each having a V-shaped cross section are formed by the respective shaver surfaces.

Furthermore, there is a gap between one side of the common movable shave 10 (on the right side in the figure) of the brush 1 and the second drive pulley 6.7 and the fixed shave 9'' of the second drive pulley 7 located on the right side in the figure. A spring 12 is compressed to bias the movable shaver 10 in the left direction toward the fixed shovel 9 of the first drive pulley 6 located on the left side in the figure.

On the other hand, the driven shaft 2 has first and second driven pulleys 1
3 and 14 are arranged in parallel in the axial direction via the boss portion 15.16, and the first driven pulley 13 is arranged on the driven shaft 2 in correspondence with the first driving pulley 6, and is rotated on the driven shaft 2. A fixed shave 17 in the form of a flange is supported in a non-slidable manner and is slidably and rotatably connected to the boss portion 15 of the fixed shave 17 by a spline connection so as to face the fixed shave 17. A belt groove 21 having a V-shaped cross section is formed between the fixed shave 17 and the movable shave 19 by the respective shave surfaces. On the other hand, the first
The driven pulley 14 is disposed on the driven shaft 2 in correspondence with the second driving pulley 7, and includes a flange-shaped fixed shave 18 that is rotatably and non-slidably fixed to the driven shaft 2, and a fixed shave 18 that is fixed to the driven shaft 2 in a fixed manner. It consists of a flange-shaped movable shaver 20 which is slidably and rotatably connected to the boss portion 16 of the fixed shaver 18 by spline connection so as to face each other, and between the fixed shaver 18 and the movable shaver 20, A belt groove 21 having a V-shaped cross section is formed by each shaved surface. Also, the output shaft 3 on the back side of the movable shuv 20 of the second driven boob 914 located on the right side in the figure
A spring seat 22 is rotatably fixed to the spring seat 22, and between the spring seat 22 and the back surface of the movable shuv 20, the movable shovel 20 is moved in the direction toward the fixed shuv 18 (
A spring 23 is compressed and biased in the left direction in the figure. Furthermore, the first driven pulley 1 located on the left side in the figure
A ring-shaped cam member 40 having a cam surface 40a is rotatably supported by a bearing 41 on the movable shave 19 of No. 3.
An operating lever 24 is provided for moving the fixed shaver toward and away from the fixed shaver 17.

Further, between the belt grooves 11 and 21 between the first driving pulley 6 and the first driven pulley 13, and between the belt grooves 11'' and 21 between the second driving pulley 7 and the second driven pulley 14, a first and second V-belts 25° and 26 are wound around each other.Then, by operating the operating lever 24, the T
51 The movable sheave 19 of the driven pulley 13 is moved toward and away from the fixed sheave 17 to variably adjust the effective radius of the first drive pulley 6 and the first driven pulley 13 with respect to the first V-belt 25. Movable shave 1
9 approaches the fixed shave 17, the effective radius of the first driven pulley 13 is increased, and the tension of the first V-belt 25 causes the common movable shave 10 of the first drive pulley 6 to resist the biasing force of the spring 12. by moving the effective radius of the first drive pulley 6 away from the fixed shaver 9.
Make it smaller than 13. At the same time, the effective radius of the second drive pulley 7 is increased, and the tension of the second V-belt 26 causes the movable shave 20 of the second driven pulley 14 to be moved by the spring 2.
By separating the second driven pulley 14 from the fixed shaver 18 against the urging force of 3 and making the effective radius of the second driven pulley 14 smaller than that of the second drive pulley 7, the While changing the gear ratio, the output shaft 3 is rotated in the opposite direction to the drive shaft 1 via a bevel gear mechanism 39, which will be described later. On the other hand, when the movable shaver 19 of the first driven pulley 13 is separated from the fixed shaver 17, the first
The effective radius of the driven pulley 13 is made small, and the first V belt 25
The tension of the common movable shaver 1 of the first drive pulley 6
0 approaches the fixed shaver 9 by the biasing force of the spring 12 to make the effective radius of the first driving pulley 6 larger than that of the first driven pulley 13. At the same time, the effective radius of the second driving pulley 7 is made smaller, and the tension of the second V-belt 26 causes the movable shave 20 of the second driven pulley 14 to approach the fixed shave 18 by the biasing force of the spring 23. By making the effective radius of the second drive pulley 14 larger than that of the second drive pulley 7, the gear ratio between the drive shaft 1 and the driven shaft 2 (output shaft 3) is changed, and the output shaft 3 is connected to the drive shaft via the bevel gear mechanism 39. It is configured to rotate in the same direction as 1.

Further, a first bevel gear 27 is rotatably fixed to the inner end of the gear box 4 of the driven shaft 2, and on the right side in the figure, a second bevel gear 28 is opposed to the first bevel gear 27 and has a bearing 29. .29, it is supported by the driven shaft 2 so as to be relatively rotatable. Then, the second bevel gear 2
Reference numeral 8 denotes a bevel gear 30 which is rotatably fitted and connected to the end of the boss portion 15 of the first driven pulley 13 (fixed pulley 17), and another bevel gear 31 which meshes with the bevel gear 30.
The drive shaft 1, more specifically, the first drive pulley 6
The first driven pulley 13, which is rotated by belt transmission of the rotational force of the first driven pulley 13, rotates in the opposite direction to the first bevel gear 27.

Further, between the first and second bevel gears 27.28, a plurality of third bevel gears 33.33°... are arranged radially at predetermined intervals so as to mesh with the first and second bevel gears 27.28. It is located in In addition, each of the above third
A shaft 34 is rotatably inserted into the bevel gear 33, and one end of the shaft 34 is integrally connected to a ring member 36 rotatably supported on the driven shaft 2 by a bearing 35, while the other end is integrally connected to a ring-shaped output gear 38 that is located on the outer periphery of each of the third bevel gears 33 and meshes with a gear 37 that is rotatably fixed to the output shaft 3. 38 is rotatably supported on the driven shaft 2 between the first and second bevel gears 27 and 28, and is rotatably supported on the driven shaft 2 between the first and second bevel gears 27.
The bevel gear 33 is rotatably connected to the output gear 38 around the shaft 34.
is supported by Then, when the first and second bevel gears 27, 28 rotate in opposite directions at the same rotation speed by the neutral switching operation of the operating lever 24, only the third bevel gears 33 are rotated around the shaft 34, and the While the rotation of the output gear 38 is stopped, when the first and second bevel gears 27,28 rotate in opposite directions at different rotation speeds due to the speed change operation of the operating lever 24, the output gear A bevel gear mechanism 39 is configured to rotate the output shaft 3 by rotating the output shaft 38 together with a third bevel gear.

Further, a support member 42 is attached to the side surface of the gear box 4, and a ring-shaped cam follower 43 is disposed on the support member 42 via a mounting ring 44 so as to move toward and away from the cam member 40. ing. On the other hand, a pulley 45 is attached to the output shaft 3, and the pulley 48 is connected to a pulley 48 attached to the shaft portion 47 of an electromagnetic clutch 46 located above the pulley 45 and turned ON by the neutral operation of the operating lever 24. Drive is connected via. Further, a screw member 50 is rotatably supported on the shaft portion 47 of the electromagnetic clutch 46, and a bar 51 provided on the camfoil and lower 43 is threadedly connected to the screw member 50. There is. If the output shaft 3 is rotating when the operating lever 24 is in the neutral position, the rotation is transmitted to the screw member 50 via the pulley 45.4B by the belt, and the screw member 46 is screwed. By advancing the cam follower 43, the cam member 40
The output shaft 3 is engaged with the cam surface 40a of the output shaft 3.
The rotating operation of the rotor is forcibly stopped.

Next, the operation of the above embodiment will be explained.

First, when the operating lever 24 is in the neutral position, as shown in FIG.
, 14 and the first and second drive pulleys 6.7 are at intermediate values in the variable range, and the rotation of the drive shaft 1 is directly transmitted to the driven shaft 2 without being changed in speed. Therefore, the first bevel gear 27 connected to the driven shaft 2 and the second bevel gear 28 rotated by the first driven pulley 13 via the bevel gears 30 to 32 rotate in opposite directions at the same rotation speed. As a result, only each third bevel gear 33 rotates around the shaft 34, and the output gear 38 that rotatably supports each third bevel gear 33 does not rotate. The drive-coupled output shaft 3 does not rotate. In other words, a neutral state is ensured.

From this state, if the operating lever 24 is operated to move the movable shave 19 of the first driven pulley 13 closer to the fixed shave 17 as shown in FIG. Due to the tension of the first V-belt 25, the common movable shaver 10 of the first driving boob 96 is separated from the fixed shaver 9 against the biasing force of the spring 12, and the effective radius of the first driving pulley 6 becomes the first driven pulley. Pulley 1
It becomes smaller than 3. At the same time, the second drive pulley 7
The effective radius of the second driven pulley 14 increases, and the movable shave 20 of the second driven pulley 14 resists the biasing force of the spring 23 and moves away from the fixed shave 18 due to the tension of the second V-belt 26, and the effective radius of the second driven pulley 14 increases. 2 drive pulley 7. As a result, the first bevel gear 27 rotates at high speed, and the second bevel gear 28 rotates at a low speed in the opposite direction to the first bevel gear 27, and the output gear 38 is driven at a rotation speed corresponding to the difference in relative rotation speed. The output shaft 3 is rotated in the same direction as the shaft 2, and this rotation causes the output shaft 3 to rotate in the opposite direction to the drive shaft 1.

On the other hand, if the operating lever 24 is operated in the opposite direction to the above to separate the movable shave 19 of the first driven pulley 13 from the fixed shave 17 as shown in FIG. The effective radius of the first driving pulley 6 becomes smaller, and the common movable shave 10 of the first driving pulley 6 approaches the fixed shave 9 due to the biasing force of the spring 12 due to the tension of the first V-belt 25, so that the effective radius of the first driving pulley 6 becomes the first It is larger than the driven pulley 13. At the same time, the effective radius of the second driving pulley 7 becomes smaller, and the tension of the second V-belt 26 causes the movable shave 20 of the second driven pulley 14 to approach the fixed shave 18 due to the biasing force of the spring 23, causing the second driven pulley to move closer to the fixed shave 18. 14 effective radius of the second drive pulley 7
becomes larger than As a result, the first bevel gear 2
7 rotates at a low speed, and the second bevel gear 28 rotates at a low speed.
The output gear 38 rotates at high speed in the opposite direction to the bevel gear 27, and the output gear 38 rotates to the driven shaft 2 at a rotation speed corresponding to the difference in relative rotation speed.
This rotation causes the output shaft 3 to rotate in the opposite direction.
rotates in the same direction as the drive shaft 1.

As described above, in this embodiment, by moving the movable shaver 19 of the first driven pulley 13 toward and away from the fixed shaver 17, the rotation of the drive shaft 1 is controlled by the first drive pulley 6, the second drive pulley 7, and the second drive pulley 7. The speed is changed and transmitted to the driven shaft 2 via the driven pulley 14, and due to the difference in the relative rotational speed of the first and second bevel gears 27 and 28, which rotate in opposite directions due to the rotational movement of the driven shaft 2 and the drive shaft 1. , output shaft 3
By controlling the rotation and stopping of the
A large braking force is generated in the neutral state, and a stable neutral state can be easily ensured. This eliminates the need to install a clutch or brake, and the device can be made more compact.

Further, in the above embodiment, two first and second V belts 25 and 26 are used to move the first driven pulley 13 and the second driven pulley 6 so that when one becomes high speed, the other becomes low speed. Therefore, the relative speed difference can be taken quickly and excellent speed response can be obtained.Furthermore, the diameter of the pulley can be reduced by sharing the load, the width of the belt can be reduced by sharing the speed ratio, and the operation movement of the operating lever 24 can be reduced. It is also possible to reduce the amount of water used.

Furthermore, in the embodiment described above, the rotational movement of the output shaft 3 in the neutral state is transmitted to the screw member 50 by the belt through the pulleys 45 and 48 to cause the screw member 46 to advance, thereby moving the cam follower 43 toward the cam member 40. Cam surface 40
Since the output shaft 3 is engaged with the output shaft 3, the rotational movement of the output shaft 3 can be forcibly stopped, resulting in excellent safety.

In the above embodiment, the cam surface 40a of the cam member 40 is moved by moving the cam follower 43 in the direction of the output shaft 3.
Although the cam follower 43 is engaged with the cam surface 40a of the cam member 40 by rotating the cam follower 43 around the output shaft 3, for example, the cam follower 43 may be engaged with the cam surface 40a of the cam member 40.

(Effects of the Invention) As described above, according to the present invention, a pair of fixed shaves are rotatably and slidably supported on the drive shaft between the two fixed shaves, and a A pair of first and second drive pulleys, each consisting of a movable shaver forming a belt groove, are arranged opposite to the drive shaft, and - a pair of fixed shavers and a sliding pulley are provided for each fixed shaver. A pair of first and second driven pulleys, each consisting of a pair of movable shavers that are movably and rotatably supported and that form a belt groove between each of the fixed shavers, are disposed on the driven shaft. By moving the movable shave of the first driven pulley toward and away from the fixed shave, the first bevel gear rotatably fixed to the driven shaft and the driven shaft can rotate opposite to the first bevel gear. When the second bevel gear supported by the first driven pulley rotates in opposite directions to the first bevel gear, the third bevel gear meshes with both boxes 1 and the second bevel gear.
While only the bevel gear is rotated and the rotation of the output gear is stopped, when the first and second bevel gears rotate in opposite directions to each other at different rotation speeds, the output gear is rotated together with the third bevel gear according to the difference in their relative rotation speeds. to rotate the output shaft. Therefore, the large braking force generated in the neutral state makes it easy to maintain the neutral state, which eliminates the need to install a clutch or brake, allowing the device to be made more compact.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of the continuously variable transmission in a neutral state, and FIGS. 2 and 3 are views corresponding to FIG. 1 in a variable speed state. 1... Drive shaft, 2... Driven shaft, 3... Output shaft, 6
...first drive pulley, 7...second drive pulley, 9,
1゜17.18...Fixed shave, 10,19.20
...Movable shave, 11.11-. 21... Belt groove, 13... First driven pulley, 14... Second driven pulley, 25... First V belt, 26... Second V belt, 27... First bevel gear, 28 ...Second bevel gear, 33...Third bevel gear, 38...Output gear, 39...Bevel gear mechanism.

Claims (1)

[Claims] (1) A drive shaft, a driven shaft, and an output shaft that are arranged parallel to each other, and a pair of shafts that are each arranged to face the drive shaft in the axial direction and are rotationally integrally and non-slidably fixed to the drive shaft. Consisting of a fixed shave and one movable shave that is rotatably and slidably supported on a drive shaft between the fixed shaves and has shave surfaces on both sides for forming belt grooves between each of the fixed shaves. a pair of first and second drive pulleys arranged on the driven shaft in correspondence with the first drive pulley;
A fixed shave that is rotatably but non-slidably supported on a driven shaft, and a movable shave that is slidably and rotationally integrated with the fixed shave and that forms a belt groove between the fixed shave and the fixed shave. a first driven pulley arranged on the driven shaft in correspondence with the second driving pulley;
A fixed shave that is rotatably and non-slidably fixed to a driven shaft, and a shave surface that is slidably and rotatably fixed to the fixed shave and that forms a belt groove between the fixed shave and the fixed shave. a second driven pulley consisting of a movable shaver having a movable shave; and a belt groove between the first drive pulley and the first driven pulley;
and a movable shaver of each pulley that is wound between the belt grooves of the second drive pulley and the second driven pulley to change the gear ratio between the drive shaft and the output shaft. first and second V-belts that change the effective radius of each pulley by moving toward and away from each other; a first bevel gear rotatably fixed to the driven shaft;
a second bevel gear rotatably supported by a driven shaft opposite to the first bevel gear and rotationally driven by the first driven pulley in a direction opposite to the first bevel gear; and a second bevel gear meshing with the first and second bevel gears. 3 bevel gear, and an output rotatably supported by the driven shaft between the first and second bevel gears, meshing with a gear rotatably fixed to the output shaft, and rotatably supporting the third bevel gear. When the first and second bevel gears rotate in opposite directions at the same rotation speed, only the third bevel gear is rotated to stop the rotation of the output gear, while the first and second bevel gears are rotated in opposite directions. a bevel gear mechanism that rotates the output gear together with a third bevel gear to rotate the output shaft according to the difference in the relative rotation speeds when the two rotate in opposite directions at different rotation speeds. Device.