JP3464909B2 - Transmission neutral holding device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission in which the output portion is rotated while rotating normally or reversely and is stopped in the neutral state between the normal rotation and the reverse rotation in order to stably maintain the neutral state. Belongs to the technical field of neutral holding devices.

[0002]

2. Description of the Related Art As an example of a belt type continuously variable transmission, a pair of rotary shafts arranged in parallel with each other is fixed to each rotary shaft so as to rotate integrally with the rotary shafts so as not to slide. A sheave and a movable sheave, which are arranged to face each other so as to form a V-shaped belt groove between the sheave and the fixed sheave on the rotating shaft, and are supported so as to be rotatable integrally and slidably, A speed change pulley mechanism having a V-belt wound between the belt grooves of these speed change pulleys,
It is known that the gear ratio between both rotary shafts is changed by changing the effective radius with respect to the V-belt by moving the movable sheave in the axial direction.

Further, conventionally, as disclosed in Japanese Patent Laid-Open No. 62-118159, the shift pulley mechanism is provided and a planetary gear mechanism (differential gear mechanism) as a gear mechanism for shifting is provided. Continuously variable transmissions are also known.
In a continuously variable transmission including such a speed change pulley mechanism and a differential gear mechanism, when the output shaft is attempted to be rotated from a stopped state by using the differential gear mechanism, the power transmission path causes the driving power and the circulation power to be changed. It will be divided into two routes. That is, in the closed circuit type differential gear device, one of the three gear elements of the differential gear mechanism is connected to the output shaft, and the rotation speed of the remaining one gear element of the differential gear mechanism is adjusted by adjusting the pulley ratio of the pulley mechanism. By changing the rotation direction and the rotation speed between the gear element and the remaining other gear elements, the rotation direction and the rotation speed of the output side gear element, that is, the output shaft are determined. At that time, driving power and circulating power are generated as power, and the output power is the driving power minus the circulating power. Which of the two power transmission paths from the input shaft to the output shaft is the drive power path or the circulating power path is determined by the rotation speed of the gear element in the differential gear mechanism, and the one with the higher rotation speed is driven. It becomes a power route. The rotation speed of the gear element represents the peripheral speed of the gear element on the pitch circle.

By the way, in a continuously variable transmission equipped with the above-mentioned transmission pulley mechanism and differential gear mechanism, in order to stably maintain the neutral state in which the rotation of the output portion is stopped, the sheave in the transmission pulley of the transmission pulley mechanism is maintained. When the transmission is in the neutral state and the torque is transmitted to the speed change pulley in the direction in which the neutral state shifts, the torque is transmitted when the transmission is in the neutral state. It is known that the torque cam mechanism is operated to move the sheave in the axial direction to return the sheave to the neutral state.

[0005]

However, when the torque cam mechanism is used as described above, there are the following problems. That is, in order to generate the restoring force to the neutral state by the small torque acting on the belt, the cam angle of the torque cam mechanism must be increased, and with the increase of this cam angle, a large running torque acts at a high load. At this time, a large operation force (operation load) is required near the neutral position, and the gear change operation force increases.

When the vehicle equipped with the continuously variable transmission is stopped on a slope, the stopping force acts on the torque cam mechanism in the opposite direction away from the neutral direction. There is also a problem that the torque that acts acts in a direction to prevent the vehicle stop state, and the stop holding force of the vehicle on a slope is reduced.

The present invention has been made in view of the above problems, and its main purpose is not limited to the continuously variable transmission in which the above-described speed change pulley mechanism and differential gear mechanism are combined, but the output section is input. For the transmission that changes the gear ratio between the input and output parts by switching between the normal rotation state, the neutral state, and the reverse rotation state with respect to the rotation of the parts, by increasing the gear shift operation force in the neutral state by taking predetermined means. (EN) A neutral state can be stably maintained without lowering the slope stopping force of an installed vehicle.

[0008]

In order to achieve the above object, the present invention utilizes the rotational torque when the output portion of the transmission rotates from the neutral state to return the operating mechanism to the neutral state. I tried to drive.

Specifically, in the first aspect of the invention, the output portion rotates in one direction with respect to the input portion rotating in a fixed direction, the neutral state in which the output portion stops rotating, and the reverse state in which the output portion rotates in the other direction. A neutral transmission including a speed change mechanism for changing the gear ratio between the input and output sections in the forward and reverse rotation states and an operation mechanism for controlling the operation of the speed change mechanism by operating the operation section. For holding devices.

Concentric to the side of the output section in the axial direction.
Disposed, the output rotation to be rotated in the same direction as the direction of rotation as relatively rotatably <br/> always in friction transmission state to the output unit sliding contact and by receiving the rotational torque of the output unit to follow the output unit Provide a member. Further, when the output unit is connected between the output rotating member and the operating mechanism and rotates in a neutral state, the rotational torque of the output rotating member that rotates following the output unit is transmitted to the operating mechanism to perform the operation. A torque transmission mechanism is provided to move the mechanism back to the neutral position.

With the above structure, when the output portion rotates to shift to the forward rotation state or the reverse rotation state in the neutral state of the transmission in which the rotation of the output portion is stopped , the axial direction of the output portion is changed. The output rotating member, which is arranged concentrically to the side and is always in sliding contact with the output portion in a frictionally transmitted state so as to be relatively rotatable , receives the rotational torque of the output portion and follows the output portion. Rotate in the direction. Since the output rotating member is connected to the operating mechanism via the torque transmitting mechanism, the rotational torque of the output rotating member that rotates following the output section is transmitted to the operating mechanism via the torque transmitting mechanism, and the rotation of the rotating member is performed. The operating mechanism is driven by the torque and moves in the direction of returning to the neutral position. As a result, no matter which direction the output unit rotates in the neutral state of the transmission, the operating mechanism is constantly restored to the neutral position, and the neutral state of the transmission can be stably maintained.

Further, as long as the output portion is rotating, the operating mechanism which receives the rotational torque from the output rotating member is urged in the direction of increasing the operating force (operating load) in the neutral direction, but from the outside. Since the load for moving the gear ratio to the neutral state is extremely small, the operating force of the operating mechanism does not increase.

Furthermore, since the operating mechanism is moved by the output rotating member that receives the rotational torque of the output section, the direction of the load for returning to the neutral state is determined according to the rotating direction of the output section, and this load direction is the output section. It acts to maintain the stop state of. Therefore, when the vehicle equipped with the transmission is stopped on a slope, the stop holding force on the slope can be favorably maintained.

According to a second aspect of the present invention, the speed change mechanism includes a speed change pulley mechanism and a differential gear mechanism that are supported on first and second rotating shafts that are parallel to each other. Use a transmission.

The speed change pulley mechanism rotatably connects both rotary shafts in a variable speed manner. A pair of speed change pulleys are arranged and supported by the rotary shafts so that the fixed sheave and the movable sheave are opposite to each other. And a belt wound between the speed change pulleys and the movable sheave rear side of the speed change pulleys, and the movable sheaves are brought into and out of contact with fixed sheaves facing each other, and the speed change pulley belts are wound. A pair of drive mechanisms for changing the diameter, an interlocking mechanism for changing the pulley ratio between the pulleys by interlocking the drive mechanisms so that the belt winding diameters of the speed change pulleys change in opposite directions. And a tension mechanism that presses the loose side span of the belt between the speed change pulleys so that the tension is greater than the tension generated on the loose side span corresponding to the pulley ratio between the pulleys.

On the other hand, the differential gear mechanism has first to third gear elements connected to each other and connects the first gear element to the first rotating shaft, while the second gear element connects to the second rotating shaft. Link.

Further, the operating mechanism is configured to control the operation of the interlocking mechanism in the speed change pulley mechanism.

The transmission has one of the first rotary shaft and the third gear element as an input section and the other as an output section, and is operated in the forward rotation state, the neutral state, and the reverse rotation by operating the operation mechanism. The belt is pressed against the movable sheaves of the two speed change pulleys in the speed change pulley mechanism in the axial direction of the rotary shaft through the interlocking mechanism and the drive mechanism, and both of them are pressed. The neutral state is restored by the difference between the pressures (hereinafter referred to as the belt thrust force in the present invention).

According to the present invention, the first rotary shaft has a power transmission path including a speed change pulley mechanism that is bridged between the first and second rotary shafts with respect to the third gear element of the differential gear mechanism, and the power transmission path. Since it is arranged in parallel to the transmission path and is connected via the power transmission path from the first gear element of the differential gear mechanism to the first rotation shaft, the first rotation shaft or the third gear of the differential gear mechanism is connected.
The power input using one of the gear elements as an input section uses one of the power transmission path including the speed change pulley mechanism or the power transmission path from the first gear element of the differential gear mechanism to the first rotation shaft as the driving power path. , The other is transmitted as a circulation power path, and then the other of the first rotary shaft or the third gear element is output as an output unit. Then, the operation mechanism is operated to control the operation of the interlocking mechanism of the speed change pulley mechanism, and the pulley ratio is changed, so that the output portion is switched to the normal rotation state, the neutral state, or the reverse rotation state with respect to the input portion.

In the above-mentioned speed change pulley mechanism, when one of the drive mechanisms is operated by the operation of the operating mechanism to move the movable sheave of the one speed change pulley in the axial direction, the other drive mechanism is also operated and the other is driven. The movable sheave of the speed change pulley of (1) moves by an operation opposite to the operation of the movable sheave of one of the speed change pulleys with respect to the fixed sheave,
The pulley ratio between the two pulleys is changed by the movement of the two movable sheaves in the opposite directions.

At this time, the drive mechanisms are arranged such that the fixed and movable sheaves of the speed change pulleys are located on opposite sides with respect to the axial direction, and the movable sheaves face the fixed sheaves facing each other from the rear side. Since the two drive mechanisms are linked by the interlocking mechanism, the belt thrust forces on the two speed change pulleys cancel each other out. Therefore, when the transmission is in the neutral state,
Both of the speed change pulleys in the speed change pulley mechanism are drive side pulleys (or driven side pulleys), and the belt tension forces are balanced because the belt tension distribution between the two pulleys is balanced. The difference becomes zero due to the above cancellation, and the neutral state is maintained.

However, when the transmission changes from the neutral state to the normal rotation side or the reverse rotation side and the belt winding diameter of one pulley of the transmission pulley mechanism becomes larger than the other, the belt tension distribution in both pulleys is increased. Is unbalanced and effective tension of the belt (difference between tension on the tension side and tension on the slack side) is generated, and the belt thrust of the pulley on the side where the belt winding diameter is increased is smaller The thrust force is larger than the thrust force, and the difference in the belt thrust force increases as the load increases. That is, if the transmission ratio changes slightly from the neutral state and the pulley ratio of the speed change pulley mechanism changes, even if there is the above-described cancellation of the belt thrust between the speed change pulleys of the speed change pulley mechanism, the speed difference between the speed change pulley mechanism and the speed change pulley mechanism is increased. The difference in the belt thrust remains, and due to the difference in the belt thrust, the pulley on the side where the belt winding diameter is increased changes so that the winding diameter becomes smaller. That is, the restoring force that automatically returns to the neutral state acts on the transmission pulley mechanism. Then, when this restoring force reaches the neutral state where the rotation of the output section is stopped, the belt thrust between both speed change pulleys is balanced and the effective tension of the belt disappears, so that the neutral state is maintained. Be drunk As a result, the neutral state of the transmission can be maintained more stably.

According to a third aspect of the present invention, the speed change pulley mechanism is configured such that the movable sheaves of both speed change pulleys are opposite to the fixed sheave.

Further, the drive mechanism is a cam mechanism, and each of the cam mechanisms includes a cylindrical rotating cam rotatably supported on a boss portion of the movable sheave of the speed change pulley via a bearing,
A fixed cam that comes into cam contact with the rotary cam, and a cam surface is formed on one of the rotary cam and the fixed cam, while the other is a cam follower that contacts the cam surface. The movable sheave is moved in the axial direction by the relative rotation of the fixed cam.

Further, the interlocking mechanism has a single link for connecting the rotating cams of both cam mechanisms.

According to this structure, when the ratio of the number of revolutions of the output portion to the input portion, that is, the transmission gear ratio is changed,
Since the rotating cams of the cam mechanisms of both speed change pulleys are interlockably connected by the interlocking mechanism having one link, the rotating cam of the cam mechanism of one pulley is rotated around the rotation axis. When the movable sheave of the pulley is moved in the axial direction by the cam contact with the fixed cam, the movable sheave of the other pulley is accompanied by a movement opposite to the moving movement of the movable sheave of the one pulley with respect to the fixed sheave. When the movable sheave moves in the opposite direction, the pulley ratio of the speed change pulley mechanism is switched and changed.

At this time, for example, the rotating cam in each cam mechanism has a cam surface inclined at a predetermined inclination angle with respect to the surface orthogonal to the rotation axis, and the fixed cam is provided with a cam follower that moves on the cam surface. Then, a force acts on the cam surface of the rotating cam from the cam follower on the fixed cam in the direction perpendicular to the cam surface, and this force is a parallel component force in the direction parallel to the rotation axis and a right angle in the direction orthogonal to the rotation axis. The latter component acts at a right angle to the line connecting the axis of the rotating shaft and the connecting point to one link of the interlocking mechanism. Since the rotating cam is restrained immovably by the connection with the link, the change of the pulley ratio with respect to the line connecting the axis of the rotating shaft and the connection point to the link is caused by the action of the right-angled component force. Regardless of the right angle and in the opposite direction to the right angle component force, a cam rotation reaction force that rotates the rotation cam around the connection point to the link is generated, and this rotation reaction force is supported by the rotation cam. On the plane passing through the center of the boss of the movable sheave and the center of the boss, which is approximately the center of the area around which the belt of the pulley is wound (the position 90 ° out of phase with the link point to the link). It acts so as to press the boss portion toward the center of the rotation shaft from one of both sides of the boss portion that are opposed to each other in the diametrical direction. That is, the cam rotation reaction force on the boss is a clearance in the sliding portion between the boss and the rotary shaft, and is a moment acting in the direction of tilting the movable sheave with respect to the rotary shaft when the movable sheave receives thrust from the belt. In the opposite direction, acts to generate a moment that makes the boss parallel to the rotation axis,
This moment offsets the original moment and reduces it, and the surface pressure distribution of the inner circumference of the boss of the movable sheave with respect to the outer circumference of the rotating shaft is dispersed in the axial direction, eliminating the large peaks that existed in the past, and the sliding resistance of the boss Becomes smaller. The smaller the sliding resistance is, the larger the load (that is, the take-out thrust) applied to the fixed point by the rotating cam of the belt-generated thrust becomes. In other words, the belt-generated thrust is taken out by the rotating cam without a large resistance. Will be transmitted as.

In the speed change pulley mechanism, the rotating cams of both cam mechanisms are set to 1 so that the opening / closing forces between the speed change pulleys are reversed and the opening / closing forces between the two pulleys partially cancel each other out.
Since it is connected by a book link and the take-out thrust force of one cam mechanism is used for the belt thrust force of the other cam mechanism, when this relationship is likened to a seesaw, gear shifting is performed with a constant pulley ratio. When not present, the extraction thrust itself becomes larger in the case of the present invention than in the conventional case, but the extraction thrust becomes the same on the drive side and the driven side, and these are balanced and the thrust extraction efficiency is the same as in the conventional case. is there. However, when changing the pulley ratio, the difference between the belt-generated thrust and the take-out thrust is the load (operating force) required for gear shifting operation, so in the conventional case, the remaining take-up force is large due to the small take-out thrust. On the other hand, in the present invention, since the ejection thrust is large, conversely, the operation force can be correspondingly small. As a result, the resistance at the time of shifting to the neutral state becomes small due to the thrust force balance of the belt between the both shifting pulleys in the above shifting pulley mechanism, and the neutral state is smoothly adjusted.

According to a fourth aspect of the present invention, pressing means for pressing the output rotating member against the output portion is provided. Further, in the invention of claim 5, the pressing means includes a support member provided in the output portion so as to rotate integrally with and separable from the output portion, and a biasing means for biasing the support member toward the output portion. The output rotating member is arranged between the output unit and the support member. According to these inventions, a desirable structure for transmitting the rotational torque of the output portion to the output rotating member can be easily obtained.

According to a sixth aspect of the present invention, the operating mechanism shifts the operating force of the operating portion to the operating portion side of the connecting portion with the torque transmitting mechanism only when the operating portion is operated by a predetermined amount or more. It shall have a dead zone part which transmits to. As a result, even when the rotational torque of the output rotating member that rotates by frictionally contacting the output portion is transmitted to the operating mechanism in the neutral state of the transmission, the operating mechanism on the transmission mechanism side of the connecting portion of the torque transmission mechanism is transmitted. Only the movable part moves within the allowable range of the dead zone part, the operating part does not move, and the neutral state can be maintained while the operating part is stopped.

According to the invention of claim 7, when the transmission is mounted on a vehicle, the input portion is drivingly connected to the engine side mounted on the vehicle, while the output portion is drivingly connected to the driving wheels of the vehicle. As a result, the same effect as that of the first aspect of the invention can be obtained.

[0032]

1 to 3 show the entire structure of a continuously variable transmission A according to an embodiment of the present invention. This transmission A is, for example, a vehicle such as a lawn mower or an agricultural machine (other than an agricultural machine). In another vehicle, it is arranged in the power transmission path between the engine and the drive wheels (neither is shown).

1 to 3, reference numeral 1 denotes a casing of a continuously variable transmission A, which is, for example, a first to a third divided casings 1a to 1a from the left side (the left side in FIG. 3) of the vehicle toward the right side. 1c is divided into three, a gear chamber 2 is formed between the first and second divided casings 1a and 1b, and a pulley chamber 3 is formed between the second and third divided casings 1b and 1c.

Inside the casing 1, a pair of front and rear first and second members extending in parallel with each other in the horizontal direction of the vehicle in a substantially horizontal plane.
The rotating shafts 5 and 15 are rotatably supported. The first rotary shaft 5 is arranged rearward of the second rotary shaft 15 and constitutes an input portion (input shaft), and is axially divided into two parts, a gear shaft portion 6 and a pulley shaft portion 7. . The left end of the gear shaft portion 6 (the left end in FIG. 3) projects to the outside of the casing 1, while the right end portion is located in the gear chamber 2, and the right end of the gear shaft portion 6 has a boss penetrating the second split casing 1b. A gear 8 having a portion 8a is concentrically and integrally fixed to the gear. The middle portion of the gear shaft portion 6 is supported by the first split casing 1a via the bearing 9, and the hollow boss portion 8a of the gear 8 is supported by the second split casing 1b via the bearing 10. .

On the other hand, the pulley shaft portion 7 is arranged in the pulley chamber 3, and the left end portion (the left end portion in FIG. 3) of the pulley shaft portion 7 has a small diameter, and the boss of the gear 5 integral with the gear shaft portion 6 is provided. Part 5
It is fitted in the inside of a so as to be able to rotate together and to be pulled out.
The right end side half of the pulley shaft portion 7 is a small diameter portion, and the sleeve 11 is externally fitted to this small diameter portion. And
The pulley shaft portion 7 is supported by the third divided casing 1c via a bearing 12 at a large diameter portion formed at the right end of the sleeve 11.

Similarly, the second rotating shaft 15 is also divided into a gear shaft portion 16 and a pulley shaft portion 17. The gear shaft portion 16
Penetrates through the second split casing 1b, and its left end (the left end in FIG. 3) is supported by the first split casing 1a through a bearing 18, and the intermediate portion is supported by the second split casing 1b through a bearing 19. ing. On the other hand, the pulley shaft portion 17 is a tubular member arranged in the pulley chamber 3, and the right end portion of the gear shaft portion 16 is spline-coupled to the left end portion (the left end in FIG. 3) of the gear shaft portion 16 so that the gear shaft portion 16 can be rotationally integrated and pulled out. The right end is supported by the third split casing 1c via a bearing 20.

With the above structure, the casing 1 is divided into the first and second divided casings 1a and 1b and the third divided casing 1c, and the rotary shafts 5 and 15 are respectively divided into the gear shaft portions 6 and 16 and the pulley. By dividing the continuously variable transmission A into two parts, that is, the shaft parts 7 and 17, the continuously variable transmission A is unitized into a planetary gear mechanism 22 and a speed change pulley mechanism 30, which will be described later, and can be divided into two parts.

Although not shown, a driven pulley, which is a V pulley, is attached to the end of the first rotating shaft 5 protruding from the casing 1 so as to rotate together. A V-belt is wound around this driven pulley and a drive pulley attached to the output shaft of the engine, and the power of the engine is transmitted through the V-belt to the first rotary shaft 5 (input section) of the transmission A.
To rotate the first rotating shaft 5 in a fixed direction.

Inside the casing 1, the output gear 25 (output part), which will be described later, rotates in one direction with respect to the first rotating shaft 5 (input part) that rotates in the fixed direction, and the neutral state in which the rotation stops. State and the reverse rotation state of rotating in the other direction, and the first rotation in the forward rotation and reverse rotation states.
A transmission mechanism 21 that continuously and continuously changes the transmission ratio between the rotary shaft 5 and the output gear 25 is housed. The speed change mechanism 21 is arranged on the left end portion of the second rotary shaft 15 in FIG. 3 and is located in the gear chamber 2 as a planetary gear mechanism 22 as a differential gear mechanism. , And a speed change pulley mechanism 30 for drivingly connecting the rotating shafts 5 and 15 with a V belt 41 so that the speed can be changed.

The planetary gear mechanism 22 includes the second rotating shaft 15
A sun gear 23 as a second gear element integrally formed with the gear shaft portion 16 located in the gear chamber 2, and a plurality of pinions 24, 24, ... (Only one shown) meshing with the sun gear 23. , Is rotatably supported by bearings 27, 27 on the side of the first split casing 1a of the gear shaft portion 16 of the second rotating shaft 15, and the pinions 24, 24,
An output gear 25 (pinion carrier) as a third gear element that rotatably carries, and is arranged on the outermost periphery and is rotatably supported by the gear shaft portion 16 via bearings 28, 28. , 24, ... A ring gear 26 as a first gear element meshing with the inner circumference. The ring gear 26 has an outer periphery on which the first rotating shaft 5
It is meshed with the upper gear 8. Also, the output gear 25
Represents an output portion of the transmission A, is meshed with a transmission gear 29 outside the transmission, and the gear 29 is drivingly connected to drive wheels (not shown).

On the other hand, the speed change pulley mechanism 30 includes the second and third split casings 1b and 1c on the first rotary shaft 5.
It has a first speed change pulley 31 arranged on the pulley shaft portion 7 in the pulley chamber 3 between them. This first speed change pulley 31
Is the sleeve 1 on the pulley shaft portion 7 of the first rotating shaft 5.
1. A flange-shaped fixed sheave 32 that is key-joined to the shaft 1 so as to rotate integrally and non-slidably at the boss, and the sleeve 11 described above.
A flange-shaped movable sheave 33 is slidably and relatively rotatably supported by the boss portion 33a on the (first rotating shaft 5) so as to face the fixed sheave 32. A pulley groove 34 is formed between them.

On the other hand, a second speed change pulley 36 having the same diameter as the first speed change pulley 31 is provided on the pulley shaft portion 17 of the second rotary shaft 15. The second speed change pulley 36 is the same as the first speed change pulley 36.
It has the same structure as the speed change pulley 31, and has a flange-shaped fixed sheave 37 key-joined to the pulley shaft portion 17 of the second rotating shaft 15 at the boss portion so as to rotate integrally and non-slidably, and to the pulley shaft portion 17. , The boss portion 38a so as to face the fixed sheave 37 in a direction opposite to the direction in which the movable sheave 33 faces the fixed sheave 32 in the first speed change pulley 31.
And a flange-shaped movable sheave 38 that is slidably and relatively rotatably coupled to each other.
A pulley groove 39 is formed between 38.

A V-belt 41, which is a block belt, is wound between the pulley groove 34 of the first speed change pulley 31 and the pulley groove 39 of the second speed change pulley 36. Each movable sheave 33, 3
8 is brought into contact with and separated from the fixed sheaves 32 and 37, respectively, to change the belt winding diameter of the pulleys 31 and 36. For example, the movable sheave 33 of the first speed change pulley 31 is replaced by the fixed sheave 3
2 and the movable sheave 3 of the second speed change pulley 36.
When 8 is separated from the fixed sheave 37, the rotation speed of the first rotating shaft 5 is increased to the second rotating shaft 15 by making the belt winding diameter of the first speed changing pulley 31 larger than that of the second speed changing pulley 36. And communicate. On the contrary, when the movable sheave 33 of the first transmission pulley 31 is separated from the fixed sheave 32 and the movable sheave 38 of the second transmission pulley 36 is brought close to the fixed sheave 37, the belt winding of the first transmission pulley 31 is reversed. By reducing the attachment diameter and increasing the belt winding diameter of the second speed change pulley 36, the rotation of the first rotary shaft 5 is decelerated and transmitted to the second rotary shaft 15.

Although not shown, the V-belt 41 has, for example, a pair of endless tension bands fitted with tension bands on the left and right side surfaces, and the left and right side surfaces other than the fitting portion are provided with pulleys 31,
36 and a large number of substantially trapezoidal blocks that can be brought into contact with the side surfaces of the pulley grooves 34 and 39 of 36, and correspond to the upper and lower surfaces of the tension bands and the upper and lower surfaces of the fitting portions of the blocks, respectively. It is for high load transmission in which the formed concavo-convex portions (not shown) are engaged with each other and the block is locked and fixed to the tension band in the belt longitudinal direction, and can withstand high lateral pressure.

Movable sheave 33 of the first speed change pulley 31
A torque cam mechanism 45 is arranged between the boss portion 33 a of the first rotary shaft 5 and the pulley shaft portion 7 of the first rotating shaft 5. The torque cam mechanism 45 has a linear torque pin 46 fixed to the first rotating shaft 5 so as to project from the outer peripheral surface of the first rotation shaft 5 in the diametrical direction, and is rotatable with respect to the distal projection of the torque pin 46. The torque ring 47 fitted to the boss portion 33a of the movable sheave 33 is formed so as to penetrate therethrough.
Six torque cam holes 48 and 48 (only one is shown) respectively engaged with the torque ring 47 at the six ends. Although not shown, each torque cam hole 48 has a substantially triangular shape, and one side wall of the torque cam hole 48 is on the forward side inclined by a predetermined lead angle (eg, 26 °) with respect to the direction parallel to the axis of the rotary shaft 2. Similarly, on the other side wall, the cam surface is formed with a reverse cam surface which is inclined by a smaller lead angle (for example, 8 °) than the forward cam surface, so that the continuously variable transmission A (vehicle) advances. The torque cam mechanism 45 is actuated during each power transmission in the reverse and reverse states, and the belt 41 is moved forward and backward.
The movable sheaves 3 move so that the thrust force against the belt is applied in the opposite direction to obtain a larger belt thrust force when moving forward than when moving backward.
3, 38 are moved to the fixed sheaves 32, 37 side, respectively.

As shown also in FIG. 2, on the pulley shaft portion 7 of the first rotary shaft 5, the movable sheave 33 is brought into contact with and separated from the fixed sheave 32 on the rear side of the movable sheave 33 in the first transmission pulley 31. The 1st cam mechanism 50 as a drive mechanism for making it operate is provided. The cam mechanism 50 includes a rotating cam 5
1, the rotary cam 51 is relatively rotatable via a bearing 52 on a cylindrical collar 56 that is fitted over the boss portion 33a of the movable sheave 33 so as to cover the torque cam holes 48. Moreover, it is externally fitted and supported so as to move integrally in the axial direction. A pair of inclined cam surfaces 51a, 51a are formed on the end surface of the rotating cam 51 on the side opposite to the first speed change pulley 31 at equal angular intervals (180 ° intervals) in the circumferential direction, and extend upward on the outer circumference. A rotary lever 53 is provided so as to integrally rotate.

A cylindrical fixed cam 54 as a cam follower integrally formed concentrically with the first rotating shaft 5 on the second split casing 1b is arranged on the rear side of the rotating cam 51. Rollers 55, 55, which are in contact with the respective cam surfaces 51a of the rotating cam 51 and roll, are rotatably supported by 54.

On the other hand, on the pulley shaft portion 17 of the second rotary shaft 15, the movable sheave 3 of the second speed change pulley 36 is provided.
A second cam mechanism 5 as a drive mechanism for bringing the movable sheave 38 into and out of contact with the fixed sheave 37 on the back side of
7 is provided. The second cam mechanism 57 has the same configuration as the first cam mechanism 50, and is externally fitted and supported on the boss portion 38a of the movable sheave 38 through a bearing 58 so as to be relatively rotatable and axially movable integrally. It has a rotating cam 59. A pair of inclined cam surfaces 59a, 59a are formed on the end surface of the cam 59 opposite to the second speed change pulley 36 at equal angular intervals in the circumferential direction, and a rotating lever 60 extending upward is rotated on the outer circumference. It is projected integrally.

On the back side of the rotating cam 59, there is arranged a fixed cam 61 as a cam follower which is formed by bulging the third divided casing 1c to the outside in a cylindrical shape concentric with the second rotary shaft 15. Rollers 62, 62 which are in contact with the cam surfaces 59a of the rotating cam 59 and roll, are rotatably supported by the cam 61.

As shown in FIGS. 2 and 4, one end of a straight rod-shaped link 65 extending in the horizontal direction is swingably connected to the tip of the rotary lever 53 of the first cam mechanism 50 via a pin 66. Has been done. The other end of the link 65 has a first end 65a extending horizontally on a vertical plane substantially the same as the one end.
And then bent from the other end of the intermediate part of the link 65
The end portion 65a is divided into a second end portion 65b extending in parallel to the side, and the tip end of the turning lever 60 of the second cam mechanism 57 is swingably connected to the second end portion 65b via a pin 67. An interlocking mechanism 68 is constituted by the rotating levers 53 and 60, the link 65 and the pins 66 and 67. By this interlocking mechanism 68, the cams 51, 59 of the cam mechanisms 50, 57 are linked to each other, and the movable sheave 3
The movable sheaves 33, 38 are moved in the axial direction by rotating around the boss portions 33a, 38a of the rollers 3, 38 and rolling the rollers 55, 62 on the respective cam surfaces 51a, 59a of the fixed sheaves 32. , 37 opposite to each other, the effective radii of the pulley grooves 34, 39, that is, the belt winding diameter of the pulleys 31, 36 are made variable to change the pulley ratio between the speed change pulleys 31, 36. I have to.

Further, an operation mechanism 70 for controlling the operation of the speed change mechanism 21, specifically, the interlocking mechanism 68 of the speed change pulley mechanism 30 is provided. That is, in the upper part of the casing 1 between the first and second rotary shafts 5 and 15, the operation shaft 7 extending parallel to the rotary shafts 5 and 15 is provided.
1 is rotatably supported in a state of penetrating the first and second divided casings 1a and 1b in a liquid-tight manner, and an inner end portion of the operation shaft 71 is located in the pulley chamber 3. This operation axis 7
A rotary arm 72 extending substantially upward is fixedly attached to the inner end of the rotary body 1 so as to rotate together. One end of a rod 73 is swingably connected to the tip of the rotary arm 72 by a pin 74. As shown in FIG. 4, the other end of the rod 73 has a link 65 in the interlocking mechanism 68 of the speed change pulley mechanism 30.
Is pivotally connected to the tip of the first end portion 65a via a pin 75.

As shown in FIG. 1, a base end portion of a swing lever 77 is rotationally integrally attached and fixed to an outer end portion of the operation shaft 71 outside the casing 1, and a tip end portion of the swing lever 77 is fixed to the end portion. One end of the link 78 is swingably connected.
The other end of the link 78 is connected to an operation unit (for example, an operation lever) (not shown) operated by a vehicle driver or the like. Although not shown, this operation unit is operated to move between the operation positions of the forward maximum speed position, the neutral position, and the reverse maximum speed position by a vehicle driver or the like. It is transmitted to the operating shaft 71 via the lever 77 to move the operating shaft 71 to the forward maximum speed position Fm.
ax, neutral position N and reverse maximum speed position Rmax
(Both are shown in the angular position of the rotating arm 72 in FIG. 1)
Between them, and the interlocking mechanism 68 is operated to move the rotary levers 53 and 60 protruding from the rotary cams 51 and 59 between the forward maximum speed position, the neutral position and the reverse maximum speed position. By rotating and changing the pulley ratio of the speed change pulley mechanism 30, the output gear 25 (output part) as the pinion carrier of the planetary gear mechanism 22 is moved to the first rotary shaft 5.
The (input section) is switched to the normal rotation state, the neutral state, or the reverse rotation state to shift gears. In addition, the planetary gear mechanism 2
By setting the gear ratio between the two gear elements and the coupling gear ratio of the gear 8 with respect to the planetary gear mechanism 22, the output gear 25 is rotated in the reverse direction with respect to the first rotation shaft 5 in the forward traveling state of the vehicle.
The rotation speed of the ring gear 26 drivingly connected to the rotation shaft 5 is higher than the rotation speed of the sun gear 23 connected to the second rotation shaft 15.

Further, the operating mechanism 70 includes the link 78.
And a tip portion of the rocking lever 77, that is, an operating portion side (upstream side of an operating force transmission path from the operating portion to the speed change mechanism 21) with respect to a connecting portion with a torque transmission mechanism 102 described later.
Only when the operating portion is operated by a predetermined amount or more, the operating force of the operating portion is transmitted to the swing lever 77, that is, the interlocking mechanism 68 of the speed change mechanism 21, only when the operating portion is operated to be smaller than the predetermined amount. Is provided with a dead zone portion 79 that makes transmission impossible. The dead zone portion 79 is provided at one end portion of the link 78 and a pin 80 fixed to the tip end portion of the swing lever 77, and the pin 80 is engaged so as to be movable along the link length direction. The engaging portion 81 includes a long groove (or a long hole) that slidably engages the pin 80 by a predetermined distance. When the transmission A is in the neutral state, the operating portion is in the neutral position. At this time, only the operating mechanism 70 closer to the speed change mechanism 21 than the swing lever 77 can be moved within the relative movable range of the pin 80 at the engaging portion 81 without moving the operating portion.

Of the pair of spans of the V-belt 41 stretched between the first and second speed change pulleys 31 and 36, the span on the loose side is pressed outward from the inner surface of the belt 41.
A tension mechanism 84 is provided for generating a belt thrust by applying a tension to the belt. This tension mechanism 84
Is a first tension arm 85 in which a boss portion is rotatably supported by a bearing portion projecting concentrically around the second rotary shaft 15 in the second split casing 1b, and a boss portion of the first tension arm 85. A second tension arm 86 having a boss portion that is rotatably supported on the upper side. As shown in FIG. 2, the second tension arm 86 is
Extends toward the first rotary shaft 5 and its tip is curved downward.

The base end of a tension shaft 87 extending parallel to the rotary shafts 5 and 15 is fixedly attached to the tip of the first tension arm 85. The position of the tip of the tension shaft 87 is determined by the speed change pulley. Corresponding to the pulley grooves 34, 39 in 31, 36, the V-belt 4
A first tension pulley 88 capable of pressing one of the first (upper) spans from the inner surface is rotatably supported via a bearing (not shown).

On the other hand, a base end of a tension shaft 89 extending parallel to the rotary shafts 5 and 15 is attached and fixed to an intermediate portion of the second tension arm 86, and a tip end portion of the tension shaft 89 is also attached to the speed change pulleys 31 and 36. A second tension pulley 90, which corresponds to the pulley grooves 31 and 36 and is capable of pressing the other (lower) span of the V belt 41 from the inner surface, is rotatably supported at its tip end via a bearing (not shown). Has been done.

A spring attachment arm 92 extending downward is integrally attached to the boss portion of the first tension arm 85, and between the tip of the spring attachment arm 92 and the tip of the second tension arm 86. Is applied with a tension spring 93. The tension spring 93 urges the first tension arm 85 to rotate counterclockwise in FIG. 2 and the second tension arm 86 to rotate clockwise, respectively. Both tension pulleys 88 and 90 respectively press the inner surface of the span of the V-belt 41. Further, the rotational biasing force of the tension spring 93 with respect to the tension arms 85 and 86 causes the tension pulleys 88 and 90 to press the slack side span of the belt 41 with a tension larger than the maximum tension generated in the slack side span. The belt thrust is generated by this tension.

Further, on the outer side of the output gear 25 forming the pinion carrier of the planetary gear mechanism 22 (on the side of the first split casing 1a), a thin plate annular brake pad 95 serving as an output rotating member is disposed relative to the output gear 25. It is rotatably and concentrically arranged. The inner diameter of the brake pad 95 is set to approximately half the outer diameter of the output gear 25, and the outer diameter is set to a size slightly smaller than the outer diameter of the output gear 25. It corresponds to the department. Then, the brake pad 95 is connected to the output gear 25.
Of the outer peripheral surface 25a (side surface on the side of the first split casing 1a) of the output gear 25 that is always in sliding contact with the output gear 25 by friction transmission.
The output gear 25 rotates in the same direction as the output gear 25.

That is, the brake pad 95 is constantly pressed against the outer surface 25a of the output gear 25 by the pressing mechanism 96. The pressing mechanism 96 has a thin plate annular support member 97 arranged concentrically outside the output gear 25, and the support member 97 is slightly larger than the inner diameter of the output gear 25 (outer diameter of the bearing 27). It has an inner diameter and an outer diameter of the same size as the outer diameter of the brake pad 95, and the outer peripheral half corresponds to the brake pad 95.
It is desirable that the brake pad 95 has a high coefficient of static friction.

A plurality of support pins 98, 98, ... Extending in parallel to the output gear 25 and slidably passing through the output gear 25 are provided at positions radially inward of the brake pad 95 in the output gear 25. (Only one shown)
Are arranged and supported at equal intervals in the circumferential direction, and one end portion of each of the support pins 98, 98 ,.
The support member 97 is integrally connected to the (a side) by caulking or the like, whereby the support member 97 is provided so as to be rotatable integrally with and separable from the output gear 25.

Further, the other end side portion (second divided casing 1b side portion) of each of the support pins 98 projects above the inner side surface (side surface on the second divided casing 1b side) of the output gear 25, and the tip of the other end portion. A spring receiver 99 is attached to the. The support member 97 is provided between the spring bearing 99 and the inner side surface of the output gear 25, and
A compression spring 100 as a biasing means for biasing toward a is compressed around the support pin 98. The brake pad 95 is arranged so as to be sandwiched between the output gear 25 and the support member 97. The urging force of the support member 97 due to the spring force of the compression spring 100 causes the brake pad 95 to move to the output gear 25. It is pressed toward the outer peripheral surface 25a of the output gear 25 so that the outer peripheral surface 25a of the output gear 25 is always in sliding contact with the outer peripheral surface of the output gear 25, and is rotated in the same direction as the output gear 25 so as to follow the output gear 25. .

Further, the brake pad 95 and the operating shaft 71 of the operating mechanism 70 are connected by a torque transmitting mechanism 102. When the output gear 25 is rotated by the torque transmitting mechanism 102 while the transmission A is in the neutral state. First, the rotational torque of the brake pad 95 is transmitted to the operation shaft 71 of the operation mechanism 70 to move the operation shaft 71 so as to return to the neutral position.

That is, an arm portion 95a protruding outward in the radial direction is formed on a part of the outer peripheral portion of the brake pad 95, and one end portion of the link 103 is swingably connected to the arm portion 95a by a pin 104. Has been done. The link 103 extends around the operation shaft 71 in the gear chamber 2, and the other end thereof is swingably connected to a swing lever 105 mounted integrally with the operation shaft 71 through a pin 106, As a result, the brake pad 95 and the operation shaft 71 are connected to each other. In the neutral state of the transmission A in which the operation shaft 71 is in the neutral position N and the output gear 25 is not rotating, for example, when the output gear 25 rotates in the forward direction in the clockwise direction in FIG. Following the output gear 25, the brake pad 95 rotates in the same direction to pull the link 103, and the pulling operation of the link 103 moves the operation shaft 71 in the reverse direction toward the neutral position N in the clockwise direction in FIG. On the other hand, when the output gear 25 rotates counterclockwise in FIG. 1 which is the reverse direction while rotating, the brake pad 95 follows the output gear 25 in the same direction to rotate the link 103. By pushing and pushing the link 103, the operating shaft 71 is turned counterclockwise in FIG. 1, which is the forward direction toward the neutral position N. It has to.

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

An in-vehicle engine is drivingly connected to the first rotary shaft 5 of the continuously variable transmission A, and the pinion 24 of the planetary gear mechanism 22 is
Since the output gear 25 as a pinion carrier that supports 24, ... Is drivingly connected to the drive wheels of the vehicle, the rotational power of the engine is transmitted to the drive wheels after being changed by the continuously variable transmission A. At this time, in the transmission A, the planetary gear mechanism 22 and the speed change pulley mechanism 30 as the speed change mechanism 21 are arranged in parallel in the power transmission path between the first rotary shaft 5 as the input section and the output gear 25 as the output section. Therefore, during the operation of the transmission A, the power input from the first rotary shaft 5 is transmitted to the speed change pulley mechanism 30, the gear 8 on the first rotary shaft 5, and the planetary gear mechanism 22. After that, the output power is output from the output gear 25 as a pinion carrier in the planetary gear mechanism 22.

(At Neutral) Specifically, at the neutral position of the operating portion, the operating shaft 71 is
Is also positioned at the neutral position N. In this state, the output gear 25 of the planetary gear mechanism 22 has stopped rotating, the continuously variable transmission A is in the neutral state, and the rotational power of the engine is not transmitted to the drive wheels. , The vehicle stops.
In this neutral state, the first and second speed change pulleys 3
Both 1 and 36 are the drive side (or the driven side).

In addition, the tension spring 93 of the tension mechanism 84
Since the first tension arm 85 is urged in the counterclockwise direction in FIG. 2 and the second tension arm 86 is urged in the clockwise direction by the spring force of, respectively, when the operation portion is in the neutral position, The first tension pulley 88 presses the inner surface of the upper span of the V-belt 41 in FIG. 2, and the second tension pulley 90 presses the inner surface of the lower span thereof with the same pressing force.

At this time, in the speed change pulley mechanism 30, the fixed sheaves 32 and 37 and the movable sheaves 33 and 38 of the speed change pulleys 31 and 36 are arranged so as to be located on the opposite sides with respect to the axial direction. Since the cam mechanisms 50 and 57 that bring the movable sheaves 33 and 38 into and out of contact with the fixed sheaves 32 and 37, which are opposed to each other from the back side, are linked by the interlocking mechanism 68, the belt thrusts to the speed change pulleys 31 and 36 are mutually different. Offset. Therefore, in the neutral state, both of the speed change pulleys 31 and 36 are on the drive side (or the driven side), so that the belt 4 on both pulleys 31 and 36 is moved.
Since the tension distribution of 1 is balanced and the belt thrusts are equal to each other, the difference between the belt thrusts of the transmission pulleys 31 and 36 becomes zero due to the above-mentioned offset, and the neutral state is maintained.

Then, in this neutral state,
Due to an external load from the drive wheels, the output gear 25 rotates slightly to the forward side (forward rotation side) or the reverse side (reverse rotation side), and the belt winding diameter of one of the first and second speed change pulleys 31 and 36 is increased. If it is larger than the other, both pulleys 3
1 and 36, the tension distribution of the belt 41 becomes unbalanced, the effective tension of the belt 41 is generated, and the belt thrust of the pulley 31 (or 36) on the side where the belt winding diameter is increased is decreased. The belt thrust of the pulley 36 (or 31) is larger, and the difference in the belt thrust becomes larger as the load increases. This means that when the continuously variable transmission A changes slightly from the true neutral state and the pulley ratio of the speed change pulley mechanism 30 changes, the speed change pulley mechanism 3 is changed.
Despite the above-described cancellation of the belt thrust between the two pulleys 31 and 36, the difference in the belt thrust remains between the two pulleys 31 and 36. The pulley 31 (or 3 with the increased winding diameter)
This means that the winding diameter of 6) changes so as to decrease and the restoring force that automatically returns to the neutral state acts. Then, due to the action of the restoring force, the output gear 25
When it returns to the neutral state in which the rotation of the belt stops, the belt thrust between the two transmission pulleys 31 and 36 is balanced and the effective tension of the belt 41 disappears, so that the neutral state is maintained.

In addition, a brake which is pressed laterally from the support member 97 by the spring force of the compression spring 100 to the side of the output gear 25, which is a pinion carrier of the planetary gear mechanism 22, and which constantly slides in contact with the side surface of the output gear 25 in a frictionally transmitted state. Since the pad 95 is arranged and the brake pad 95 is connected to the operation shaft 71 by the torque transmission mechanism 102, the output gear 25, which has stopped rotating, is rotated by the load from the outside, and the operation shaft 71 is moved. Neutral position N
If deviated, the brake pad 95 receives the rotational torque of the output gear 25 and rotates in the same direction as the rotational direction of the output gear 25 with the rotation of the output gear 25, and the rotational torque of the brake pad 95 changes the operating shaft 71. Is transmitted to the operation shaft 71, and the operation shaft 71 rotates so as to return to the original neutral position N.

Specifically, when the output gear 25 rotates, for example, in the forward direction (clockwise direction in FIG. 1), the brake pad 95 rotates in the same direction following the output gear 25, and the link 103 moves. Pulled this link 103
The operation shaft 71 is rotated in the reverse direction (clockwise direction in FIG. 1) by the pulling operation. On the contrary, when the output gear 25 rotates in the reverse direction (counterclockwise direction in FIG. 1), the brake pad 95 also rotates in the same direction to push the link 103,
The pushing operation of the link 103 causes the operation shaft 71 to rotate in the forward direction (counterclockwise direction in FIG. 1). The rotation of the operation shaft 71 toward the neutral position N operates the transmission mechanism 21 to stop the rotation of the output gear 25.

In the operating force transmission path between the operating portion of the operating mechanism 70 and the speed change mechanism 21, a dead zone 79 is provided on the operating portion side of the connecting portion (operating shaft 71) with the torque transmitting mechanism 102. Therefore, when the operating shaft 71 tries to return to the neutral position N, the pin 80 in the dead zone 79 is freely moved by the engaging portion 81, and the restoration to the neutral position N is not restricted. Becomes As a result, no matter which direction the output gear 25 rotates from the neutral state of the continuously variable transmission A, the operating shaft 71 of the operating mechanism 70 is constantly restored to the neutral position N, and the transmission A itself is neutralized. In order to restore the state, a self-locking function occurs, so that the neutral state can be stably maintained, the vehicle does not move carelessly, and the stop stability at the time of neutral can be enhanced.

As long as the output gear 25 is rotating, the operating shaft 71 that receives the rotational torque from the brake pad 95 is urged in the neutral direction, that is, the direction in which the operating force becomes heavy. Since the load itself for moving the vehicle to the neutral state is extremely small, the operating force of the operating unit does not increase.

Moreover, since the operating shaft 71 is rotated by the rotating torque of the output gear 25, the direction of the load for returning to the neutral state is determined according to the rotating direction of the output gear 25, and this load direction is the direction of the output gear 25. It acts to maintain the stopped state. Therefore, when the vehicle is stopped on a slope while the transmission A is in the neutral state, the stop holding force on the slope can be favorably maintained.

(During Forward) Since the rotating levers 53 and 60 of the cam mechanisms 50 and 57 on the side of the speed change pulleys 31 and 36 are linked by the link 65, the speed change pulley mechanism 30 can be operated by switching the operation portion. By changing the pulley ratio of, the output rotation of the output gear 25 of the planetary gear mechanism 22, that is, the output rotation of the continuously variable transmission A can be changed to the normal rotation or the reverse rotation and the rotation speed thereof can be increased.

That is, when the operating portion is operated in the forward direction to position the operating shaft 71 at the forward position from the neutral state, the operating shaft 71 rotates the rotating lever 60 on the outer periphery of the rotating cam 59 of the second cam mechanism 57. Therefore, in the state of switching to the forward position, the cam 59 is mounted on the cam surfaces 59a and 59a of the cam roller 6 respectively.
While rotating the rollers 2, 62, the second sheave 36 rotates in one direction around the boss portion 38a of the movable sheave 38. As a result, the cam surface 59a is pushed by the roller 62 and the cam 59 moves on the second rotary shaft 15, and the cam 59 is moved.
The movable sheave 38, which is integrally movable, moves in the same direction via the bearing 58 and approaches the fixed sheave 37. As a result, the second speed change pulley 36 is closed and the belt winding diameter increases from the neutral state, and the V belt 41 is pulled toward the second speed change pulley 36 side due to the increase in the belt winding diameter.

At the same time, the rotary cam 51 of the first cam mechanism 50 moves to the first position in synchronization with the movement of the movable sheave 38 of the second speed change pulley 36 with the switching of the operating portion to the forward position. The one rotary shaft 5 is rotated in the same one direction as the cam 59 of the second cam mechanism 57. The rotation of the cam 51 eliminates the pressing force on the cam roller 55. Therefore, due to the tension of the belt 41 moving toward the second speed change pulley 36, the movable sheave 33 connected to the cam 51 and the bearing 52 through the cam 51 and the movable sheave 33 moves on the first rotary shaft 5 in the direction away from the fixed sheave 32. Move and both sheaves 3
The separation of 2, 33 opens the first speed change pulley 31, and the belt winding diameter decreases from the neutral state. As a result, the belt winding diameter of the second speed change pulley 36 is the first.
It becomes larger than the speed change pulley 31, and the rotation of the second rotary shaft 15 is accelerated and transmitted to the first rotary shaft 5. With this pulley ratio, the output gear 25 as the pinion carrier rotates in the reverse direction with respect to the first rotation shaft 5, and the drive wheels are rotationally driven in the forward direction of the vehicle by the output power of the engine.
By changing the pulley ratio to the forward maximum speed position, the rotational speed of the output gear 25 in the forward rotation direction, that is, the forward speed can be increased.

At this time, by setting the gear ratio between the gear elements of the planetary gear mechanism 22 and the coupling gear ratio of the gear 8 to the planetary gear mechanism 22, the vehicle is forwardly coupled to the first rotary shaft 5 in the forward drive state. The rotation speed of the ring gear 26 is
Since the rotation speed of the sun gear 23 connected to the second rotary shaft 15 is set to be higher than that of the sun gear 23, the ring gear 26 rotating in the opposite direction to the first rotary shaft 5 (second rotary shaft 15) is The output gear 25 rotates in a direction opposite to that of the first rotary shaft 5 (second rotary shaft 15) by rotating at a speed faster than the sun gear 23 rotating in the same direction as the first rotary shaft 5 (second rotary shaft 15). Rotate. In this state, it is necessary to make the driving force of the ring gear 26 larger than that of the sun gear 23. Therefore, the driving power is transmitted to the ring gear 26 via the gear 8, and the surplus power is circulated power from the sun gear 23 to the speed change pulley mechanism. It is transmitted to the first rotating shaft 5 via 30. That is, the input power input to the first rotating shaft 5 is transmitted from the first rotating shaft 5 to the gear 8 and the ring gear 26 of the planetary gear mechanism 22.
And the drive power sequentially transmitted through the path from the pinion 24 to the output gear 25 as the drive power path, and from the pinion 24 of the planetary gear mechanism 22 to the sun gear 23, the second
The rotary shaft 15 and the second speed change pulley 3 of the speed change pulley mechanism 30.
6, the belt 41, the first speed change pulley 31, and the first rotary shaft 5 are divided into the circulating power that is sequentially transmitted as a circulating power path. That is, generally, the frequency of use of the vehicle in the forward drive state is higher than that in the reverse drive, and since the speed change pulley mechanism 30 serves as a circulating power route during the forward drive, the drive power is applied to the belt 41 with high frequency over a long period as a whole. It is possible to transmit a circulating power smaller than that, and it is possible to reduce the transmission load of the belt 41 even at the time of high output in a forward state where it is frequently used.

Further, in the state where the speed change pulley mechanism 30 serves as the circulating power path, the circulating power passes from the pinion 24 of the planetary gear mechanism 22 to the sun gear 23, the second rotary shaft 15, the speed change pulley mechanism 30 and the first rotary shaft 5. As the second speed change pulley 36 becomes the drive side pulley,
The first speed change pulley 31 becomes the driven pulley, and the belt 41
2, the upper span is on the loose side, but the first tension pulley 88 is the upper span of the V belt 41 in FIG.
Further, since both tension arms 85 and 86 are urged by the tension spring 93 to rotate in opposite directions so that the second tension pulley 90 presses the lower span, the inner surface of the tension side span is pressed. Second tension pulley 90
Moves to the upper side in FIG. 2 and the second tension arm 86 rotates clockwise, whereby the tension spring 93 is extended, and the first tension arm 85 also rotates clockwise by that amount. Then, the first tension pulley 88 presses the inner surface of the upper span in FIG. 2 on the loose side of the belt 41 with a predetermined pressing force to obtain the belt tension.

Further, the boss portion 33a of the movable sheave 33 of the first speed change pulley 31 and the pulley shaft portion 7 of the first rotating shaft 5 are arranged.
A torque cam mechanism 45 is disposed between the torque cam mechanism 45 and the torque cam mechanism 45, and forward and backward cam surfaces are formed on both side walls of each torque cam hole 48 of the torque cam mechanism 45. Movable sheave 33
When the first rotating shaft 5 and the first rotating shaft 5 rotate relative to each other, the advancing side cam surface of each torque cam hole 48 comes into contact with the torque ring 47 at the tip of the torque pin 46, and the movable sheave 33 is axially pressed away from the fixed sheave 32. To the rotation cam 5 of the first cam mechanism 50 by the movement of the movable sheave 32.
The movable sheave 38 of the second speed change pulley 36 is pressed toward the fixed sheave 37 side via the interlock mechanism 68, the rotation cam 59 of the second cam mechanism 57, and the belt 4 at the speed change pulley 36.
The thrust for 1 can be increased.

The tension spring 9 of the tension mechanism 84 is
Both tension arms 85, 86 are urged to rotate in opposite directions by the urging force of 3, and the tension pulleys 88,
90 presses the inner surface of the slack side span of the belt 41, and the pressing causes tension on the belt 41.
Since this tension is larger than the maximum tension generated in the slack side span, this belt tension causes the pulley 3 of the belt 41 to move.
A wedge effect is generated on the wheels 1 and 36 to generate thrust, and the thrust transmits power between the pulleys 31 and 36 via the belt 41.

(Reverse travel) On the other hand, when the operation portion 71 is operated in the reverse travel direction to position the operation shaft 71 at the reverse travel position, the cam 51 of the first cam mechanism 50 causes each of the respective cams 51 to move in the reverse travel position. Cam surface 5
While rotating the cam roller 55 on 1a, the cam roller 55 rotates in the other direction around the boss portion 33a of the movable sheave 33 of the first transmission pulley 31. As a result, the cam surface 51a is pushed by the roller 55 and the cam 51 moves on the first rotary shaft 5, and the movable sheave 33, which is integral with the cam 51, moves in the same direction and approaches the fixed sheave 32. . As a result, the first speed change pulley 31 is closed and the belt winding diameter increases from the neutral state, and the V belt 41 is pulled toward the first speed change pulley 31 side due to the increase in the belt winding diameter.

In addition, the cam 59 of the second cam mechanism 57 causes the cam 59 of the second cam mechanism 57 to move to the second rotary shaft 1 in accordance with the switching of the operating portion to the reverse position.
5 is rotated in the same other direction as the cam 51 of the first cam mechanism 50. The rotation of the cam 59 causes the cam roller 62 to rotate.
There is no pressure against. Therefore, the tension of the belt 41 moving to the side of the first speed change pulley 31 causes the cam 59 to move.
And the movable sheave 38 connected thereto via the bearing 58 moves on the second rotary shaft 15 in the direction away from the fixed sheave 37, and the separation of the sheaves 32, 33 opens the second speed change pulley 36 to open the belt. The winding diameter decreases from the neutral state. As a result, the belt winding diameter of the first speed change pulley 31 becomes larger than that of the second speed change pulley 36, and the rotation of the first rotary shaft 5 is accelerated and transmitted to the second rotary shaft 15. With this pulley ratio, the output gear 25
When the rotation direction of the drive wheel is in the normal rotation state with respect to the first rotation shaft 5 and the drive power of the engine is driven to rotate in the reverse direction of the vehicle, and the pulley ratio is changed to the reverse maximum speed position, the output gear 25 rotates in the reverse direction. The rotational speed in the direction, that is, the reverse speed can be increased.

At this time, the first rotary shaft 5 (the second rotary shaft 1
5) the sun gear 23 rotating in the same direction as the first rotation shaft 5
The ring gear 2 that rotates in the opposite direction to the (second rotating shaft 15)
The output gear 25 is rotated at a speed higher than 6 to rotate in the same direction as the first rotary shaft 5 (second rotary shaft 15). In this state, it is necessary to make the driving force of the sun gear 23 larger than that of the ring gear 26. Therefore, the driving power is transmitted to the sun gear 23 via the speed change pulley mechanism 30, and the surplus power is circulated from the ring gear 26 to the gear. It is transmitted to the first rotating shaft 5 via 8. That is, contrary to the above-described forward movement, the input power to the first rotary shaft 5 is transmitted from the first rotary shaft 5 to the speed change pulley mechanism 30, the second rotary shaft 15, and the planetary gear mechanism 2.
The drive power sequentially transmitted through the path from the second sun gear 23 to the output gear 25 as the drive power path, and from the output gear 25 as the pinion carrier of the planetary gear mechanism 22 to the pinions 24, 24, ..., The ring gear 26, the gear 8 And the circulating power transmitted as a circulating power path. Since the speed change pulley mechanism 30 serves as a driving power path in this way, a large driving power acts on the V-belt 41, which may reduce the durability thereof. However, as described above, the vehicle is used in a reverse drive state. Since the frequency is generally lower than when the vehicle is moving forward, the state in which a high transmission load is applied to the V belt 41 is only for a short time, and the durability of the belt 41 is not significantly reduced.

In this reverse drive state, the driving power is the transmission pulley mechanism 30, the second rotating shaft 15, the planetary gear mechanism 22.
Is transmitted to the output gear 25 via the sun gear 23 of the first gear pulley 31, the second gear pulley 36 becomes the driven pulley while the second gear pulley 36 becomes the driven pulley, and the span of the belt 41 on the lower side in FIG. Is on the loose side. At this time as well, both tension arms 85 and 86 are urged to rotate in the opposite directions by the tension spring 93, so that the first tension pulley 8 pressing the inner surface of the tension side span in the same manner as above.
8 moves to the lower side in FIG. 2, and the first tension arm 85
2 rotates counterclockwise, the second tension arm 86 also rotates counterclockwise by the spring force of the tension spring 93, and the second tension pulley 90 is on the loose side of the belt 41. A belt tension is obtained by pressing the inner surface of the lower span with a predetermined pressing force.

Further, in this reverse drive state, when the movable sheave 33 of the first speed change pulley 31 and the first rotary shaft 5 rotate relative to each other due to the transmission load of the speed change pulley mechanism 30, the reverse side cam surface of each of the torque cam holes 48 is changed. The movable sheave 33 comes into contact with the torque ring 47 at the tip of the torque pin 46 so that the movable sheave 33 is fixed.
This movable sheave 3 moves axially in the direction toward the 2 side.
By the movement of 3, the thrust of the first speed change pulley 31 with respect to the belt 41 can be increased.

Therefore, in this embodiment, as described above, the planetary gear is set so that the rotation speed of the ring gear 26 is always higher than the rotation speed of the sun gear 23 on the forward side, which is frequently used in the forward or reverse drive state of the vehicle. The gear ratio between the gear elements of the mechanism 22 and the gear 8 for the planetary gear mechanism 22.
Since the connection gear ratio of is set, the transmission pulley mechanism 3
The frequency of transmission of small circulating power to the belt 41 of 0 can be increased and the frequency of transmission of large driving power to the belt 41 can be reduced, so that the burden on the belt 41 can be reduced and separately. The forward / reverse rotation state of the continuously variable transmission A can be easily obtained without the need for the forward / reverse rotation mechanism.

Further, the boss portion 33 of the movable sheave 33, 38 in each shift pulley 31, 36 of the shift pulley mechanism 30.
a, 38a, the rotation cams 51 of the cam mechanisms 50, 57,
59 is supported via bearings 52 and 58, and the rotary levers 53 and 60 on the outer circumferences of both rotary cams 51 and 59 are connected by a single link 65. A force acts on the cam surfaces 51a, 59a of the rotary cams 51, 59 from the rollers 55, 62 supported by the fixed cams 51, 61 in a direction perpendicular to the cam surfaces 51a, 59a, and the rotation shafts 5, 15 of this force are applied. When the perpendicular component force in the orthogonal direction acts at a right angle to the line connecting the axis of the rotating shafts 5 and 15 and the connecting point to the link 65, the rotating cams 51 and 59 become immovable due to the connection with the link 65. Since it is constrained, it is at right angles to the line connecting the shaft centers of the rotating shafts 5 and 15 and the connection point to the link 65 due to the above-mentioned right-angled component force, and is in the opposite direction to the right-angled component force regardless of the change in the pulley ratio. And the rotating cams 51, 59 Cam rotational reaction force that rotates occurs around the connecting point to the link 65. This cam rotation reaction force is applied to the pulley 3 against the boss portions 33a and 38a of the movable sheaves 33 and 38 on which the rotation cams 51 and 59 are supported.
On a plane passing through the center of the bosses 33a, 38a and the substantially central position (the position 90 ° out of phase with the connection point to the link 65) in the range where the belts 41 of 1, 36 are wound, the boss 33a. , 38a from one of the diametrically opposite sides of the bosses 33a, 38a to press the bosses 33a, 38a toward the centers of the rotating shafts 5, 15. That is, the cam rotation reaction force on the boss portions 33a and 38a is
When the movable sheaves 33 and 38 receive thrust from the belt 41, the movable sheaves 33 and 38 are moved by the clearances in the sliding portions between the rotating shafts 5 and 3a and 38a.
A moment that acts in the direction opposite to the direction of tilting with respect to 15 and that makes the boss portions 33a and 38a parallel to the rotation shafts 5 and 15 acts, and this moment cancels the original moment. Getting smaller,
The surface pressure distribution on the inner circumferences of the boss portions 33a, 38a of the movable sheaves 33, 38 with respect to the outer circumferences of the rotary shafts 5, 15 is dispersed in the axial direction, and the sliding resistance of the boss portions 33a, 38a is reduced. As the sliding resistance becomes smaller, the load of the belt-generated thrust applied to the fixed point by the rotating cams 51 and 59 (that is, the take-out thrust) becomes larger. In other words, the belt-generated thrust does not have a large resistance and the rotating cam does not have a large resistance. It is transmitted to 51 and 59 as extraction thrust. When the pulley ratio is changed, the difference between the belt-generated thrust and the take-out thrust is the load (operating force) required for the gear shifting operation. Therefore, the amount of take-out thrust is large and conversely the operating force can be small. become. As a result, both the transmission pulleys 3 in the transmission pulley mechanism 30 are
Due to the thrust balance of the belt 41 between the Nos. 1 and 36, the resistance at the time of shifting to the neutral state becomes small, and the neutral state is smoothly adjusted, so that the neutral state can be held more stably.

The first tension pulley 88 constantly presses the upper span of the V belt 41 in FIG. 2, and the second tension pulley 90 constantly presses the lower span of the V belt 41. Since the tension spring 93 is urged to rotate in the reverse direction by the tension spring 93 and the tension side span of the belt 41 returns, a pressing force against the slack side span is obtained.
Even if the tension side and the slack side span of the belt 41 are switched as described above, the slack side span can be automatically pressed while keeping the distance between the tension pulleys 88 and 90 constant, which is stable. Belt tension is obtained.

Moreover, since the tension arms 85 and 86 are rotationally biased by using the tension spring 93, there is no risk of buckling of the spring as in the case of using a compression spring, and an appropriate spring constant is obtained. It is also possible to stabilize the belt tension. As described above, instead of pressing the inner surfaces of both spans of the belt 41 with the tension pulleys 88 and 90, respectively, a pair of tension pulleys are arranged so that the back surface of the span of the belt 41 can be pressed. It is also possible to apply a rotational urging force in the belt pressing direction to the tension arm that supports the belt with a tension spring.

In the above embodiment, the planetary gear mechanism 22 is used.
Although the ring gear 26 is connected to the first rotating shaft 5, the gear 22 as a pinion carrier may be connected to the first rotating shaft 5 and the ring gear 26 may be used as the output portion. In addition, the sun gear 23 may be used as an output unit. In short, one of the sun gear 23, the pinion carrier, and the ring gear 26 of the planetary gear mechanism 22 is the first rotary shaft 5, and the other one is the second rotary shaft 15. It may be connected and the rest may be used as an output unit. Furthermore, it is possible to use the pinion carrier of the planetary gear mechanism 22 as the power input section and the first rotary shaft 5 as the output section.

Further, in the above embodiment, the circulatory power is transmitted to the speed change pulley mechanism 30 when the vehicle moves forward. However, when the frequency of use of the vehicle in the reverse is higher than that in the forward, the reverse drive is performed. Circulation power may be applied to the belt 41 in this state.

In the above embodiment, the dead zone portion 79 is provided at the connecting portion between the link 78 and the tip portion of the swing lever 77. However, the dead zone portion 79 is not limited to this portion, and the torque transmitting mechanism 102 in the operating mechanism 70 is not limited thereto. It may be provided on the operating portion side of the connecting portion.

Further, in the above embodiment, the speed change mechanism 21
Is a combination of the planetary gear mechanism 22 and the speed change pulley mechanism 30, but other speed change mechanisms such as HST
(Hydro Static Transmission), ring cone, etc. may be used, and the output part rotates in one direction with respect to the input part rotating in a fixed direction, the normal state where the output stops and the reverse state where the output rotates in the other direction. Any gear mechanism may be used as long as the gear ratio is changed so that the gear ratio between the input and output portions is changed in the forward and reverse rotation states.

For example, as shown in FIG. 5, the input shaft 110a
A variable swash plate type hydraulic pump 110 having (input unit);
Fixed swash plate type hydraulic motor 111 having an output shaft 111a
And H connected by hydraulic circuits 112a and 112b in a closed circuit
In the case of ST, the brake pad 95 as described above is pressed by the spring force of the spring 120 so as to be constantly in sliding contact with the rotating body 119 (output portion) attached to the output shaft 111a of the hydraulic motor 111, and the rotational torque thereof is adjusted by the hydraulic pump 110. The operation mechanism 70 for capacity control may be transmitted so that the operation mechanism 70 returns to the neutral position, and the same effect as the above embodiment can be obtained. In FIG. 5, 113 is the hydraulic pump 1.
A charge pump drivingly connected to the ten input shafts 110a includes check valves 11 connected to the hydraulic circuits 112a and 112b.
5, 116 are connected. 114 is a charge relief valve that relieves the hydraulic oil from the charge pump 113, and 117 and 118 are hydraulic circuits 112a and 11
It is a high pressure relief valve connected to 2b.

[0096]

As described above, according to the invention of claim 1 or 7, the output part rotates in one direction with respect to the input part in the normal rotation state, the rotation state stops in the neutral state, and the other direction rotates in the reverse direction. switching so as to comprise a transmission mechanism for changing the speed ratio between the input and output unit, with respect to the transmission which is adapted to control operation by the speed change mechanism operating mechanism, the output
An output rotation member that is arranged concentrically to the side of the shaft in the axial direction and that is in sliding contact with the output unit at all times in a relatively rotatable manner and that rotates in the same direction so as to follow the output unit by its rotational torque. , This output rotation in neutral state
By transmitting the rotational torque when the member rotates following the output part to the operating mechanism and moving the operating mechanism in the direction to return to the neutral position, the direction in which the output part moves in the neutral state of the transmission Even if you try to rotate
The operating mechanism is constantly restored to the neutral position, so that it is possible to stably maintain the neutral state without increasing the shift operation force in the neutral state of the transmission and decreasing the slope stop force of the mounted vehicle.

According to the invention of claim 2, the speed change mechanism is set to 1
A transmission is a continuously variable transmission in which a transmission pulley mechanism and a differential gear mechanism having first to third gear elements are arranged in combination between a pair of rotating shafts. The first and second gear elements are drivingly connected to respective rotary shafts, and the movable sheave is connected to and separated from the movable sheave rear surface of each transmission pulley in the transmission pulley mechanism in opposite directions between the two transmission pulleys with respect to the fixed sheave facing each other. A pair of drive mechanisms is provided, and an interlocking mechanism is provided that changes the pulley ratio by operating both drive mechanisms by operating the operating mechanism so that the belt winding diameters of both speed change pulleys change in opposite directions. , One of the rotating shafts or one of the third gear elements of the differential gear mechanism is used as an input portion and the other is used as an output portion, and the output portion is rotated in a forward rotation state, a neutral state or a reverse rotation with respect to the input portion by a switching operation of the switching operation mechanism. Status The continuously variable transmission is configured so that the gears are switched and the speed is changed, and the neutral state is restored by the difference between the belt thrust (pressing force in the axial direction of the belt) of the movable sheaves of the two speed change pulleys. It is possible to stably maintain the neutral state.

According to the third aspect of the present invention, the movable sheaves of the two speed change pulleys are opposite to the fixed sheave, and the drive mechanism is rotatable on the boss of the movable sheave via the bearing. A cam mechanism having a supported cylindrical rotation cam and a fixed cam that comes into cam contact with the rotation cam is provided, and a cam surface is formed on one of the rotation cam and the fixed cam, while the other is used as a cam follower. The movable sheave is moved in the axial direction by the relative movement and the relative rotation of the fixed cam, and further, the interlocking mechanism has one link connecting both the rotating cams to each other. Due to the thrust balance of the belt between the two speed change pulleys, the resistance at the time of shifting to the neutral state is reduced, and the neutral state is adjusted smoothly, and the continuously variable transmission is neutralized. It is possible to even more stable retention of Lal state.

According to the fourth aspect of the invention, the pressing means for pressing the output rotating member against the output portion is provided. Further, in the invention of claim 5, the pressing means includes a support member provided in the output portion so as to rotate integrally with and separable from the output portion, and a biasing means for biasing the support member toward the output portion. The output rotating member is arranged between the output unit and the support member.
Therefore, according to these inventions, a preferable structure for transmitting the rotational torque of the output portion to the output rotating member can be obtained.

According to the sixth aspect of the invention, since the dead zone is provided in the operating mechanism on the operating portion side with respect to the connecting portion with the torque transmitting mechanism, the operating mechanism on the transmission mechanism side during transmission of the rotational torque of the output rotary member. Only the dead zone can be moved within the range of the dead zone, and the neutral state can be stably maintained with the operation section being positioned at the neutral position.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a gear chamber portion of a continuously variable transmission according to an embodiment of the present invention when viewed from the left side.

FIG. 2 is a cross-sectional view of a pulley chamber portion of a continuously variable transmission as viewed from the right side.

FIG. 3 is a plan sectional view showing the overall configuration of a continuously variable transmission.

FIG. 4 is an enlarged plan view showing a link of the interlocking mechanism.

FIG. 5 is an explanatory view schematically showing an HST according to another embodiment of the present invention.

[Explanation of symbols]

A continuously variable transmission 1 casing 5 First rotating shaft 15 Second rotating shaft 21 speed change mechanism 22 Planetary gear mechanism (differential gear mechanism) 23 Sun gear (second gear element) 25 output gear (3rd gear element) 26 ring gear (first gear element) 30 speed change pulley mechanism 31,36 speed change pulley 32,37 fixed sheave 33,38 movable sheave 33a, 38a Boss 34, 39 pulley groove 41 V belt 50,57 Cam mechanism (drive mechanism) 51, 59 Rotating cam 51a, 59a cam surface 54,61 Fixed cam 55,62 roller 65 links 68 interlocking mechanism 70 Operation mechanism 71 Operation axis 79 dead zone 80 pin 71 Engagement part 84 Tension mechanism 85,86 tension arm 88,90 Tension pulley 93 Extension spring 95 Brake pad (output rotating member) 96 Pressing mechanism (pressing means) 97 Support member 100 compression spring (biasing means) 102 torque transmission mechanism 110 hydraulic pump 110a Input shaft (input section) 111 hydraulic motor 119 Rotating body (output section) 120 spring

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60K 20/00-20/08 F16H 59/00-61/12 F16H 61/16-61/36 F16H 63/00-63 / 48

Claims (7)

(57) [Claims] 1. An input unit that rotates in a fixed direction is switched to a normal state in which the output unit rotates in one direction, a neutral state in which rotation stops, and a reverse state in which the output unit rotates in the other direction, and the normal rotation and A neutral holding device for a transmission, comprising: a speed change mechanism for changing a speed ratio between the input and output parts in a reverse rotation state; and an operation mechanism for operating and controlling the speed change mechanism by operating an operation part. They are arranged concentrically laterally in the axial direction, rotating in the same direction as the direction of rotation as relatively rotatably always sliding contact with friction transmission state to the output unit and receiving the rotational torque of the output unit to follow the output unit Connected to the output rotating member and the output rotating member and the operating mechanism, and follows the output unit when the output unit rotates in the neutral state.
And a torque transmitting mechanism for transmitting the rotational torque of the rotating output rotating member to the operating mechanism and moving the operating mechanism to return to the neutral position. 2. The neutral holding device for a transmission according to claim 1, wherein the transmission mechanism is arranged and supported so that the fixed sheave and the movable sheave are opposite to each other on the first and second rotating shafts that are parallel to each other. A pair of speed change pulleys, a belt wound between the speed change pulleys, and a rear surface of the movable sheave of each of the speed change pulleys. The movable sheave is moved toward and away from the fixed sheaves facing each other. The pair of drive mechanisms that change the belt winding diameter of the pulleys and the two drive mechanisms are interlocked so that the belt winding diameters of the two speed change pulleys change in opposite directions to change the pulley ratio between the pulleys. Tension for pressing the loose side span of the belt between the speed change pulley and the interlocking mechanism so that the loose side span has a larger tension than the tension generated corresponding to the pulley ratio between the pulleys. And a first and third gear elements connected to each other, and a first gear element is connected to the first rotation shaft. On the other hand, the second gear element includes a differential gear mechanism connected to the second rotating shaft, the operation mechanism is configured to control the operation of the interlocking mechanism in the speed change pulley mechanism, and the transmission is One of the first rotary shaft or the third gear element is an input part and the other is an output part, and is configured to switch between a forward rotation state, a neutral state, and a reverse rotation state by the operation of the operating mechanism to shift gears. The belt is pressed against the movable sheaves of both speed change pulleys in the speed change pulley mechanism in the axial direction of the rotary shaft through the interlocking mechanism and the drive mechanism, and the neutral state is caused by the difference between the two pressing forces. What Neutral holding device for a transmission, characterized in that it is configured to source. 3. The neutral holding device for a transmission according to claim 2, wherein the movable sheaves of the two transmission pulleys of the transmission pulley mechanism are opposite to the stationary sheave of the transmission pulley mechanism, and the drive mechanism is a cam mechanism. The cam mechanism has a cylindrical rotation cam rotatably supported on a boss portion of a movable sheave of a speed change pulley through a bearing, and a fixed cam that comes into cam contact with the rotation cam. Alternatively, a cam surface is formed on one of the fixed cams, while the other is a cam follower that contacts the cam surface, and is configured to move the movable sheave in the axial direction by rotation and relative rotation of the fixed cam. The interlocking mechanism has one link connecting the rotating cams of the two cam mechanisms to each other, and the neutral holding device for the transmission is characterized in that. 4. The neutral holding device for a transmission according to claim 1, further comprising a pressing means for pressing the output rotary member against the output portion. 5. The neutral holding device for a transmission according to claim 4, wherein the pressing means urges the support member, which is provided in the output portion so as to rotate integrally with the support member, and to be separable from the output member, toward the output portion. A neutral holding device for a transmission, comprising: an urging means, wherein an output rotating member is arranged between the output portion and the support member. 6. The neutral holding device for a transmission according to any one of claims 1 to 3, when the operating mechanism is operated to a side closer to the operating part than a connecting part with the torque transmission mechanism, the operating part is operated by a predetermined amount or more. A neutral holding device for a transmission, characterized in that it has a dead zone portion for transmitting the operating force of the operating portion to the transmission mechanism. 7. The neutral holding device for a transmission according to claim 1, wherein the input portion is drivingly connected to an engine mounted on the vehicle, while the output portion is drivingly connected to driving wheels of the vehicle. Characteristic transmission neutral holding device.