JPH0735153Y2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a continuously variable transmission that continuously changes rotation, and in particular, an improved technique of a pulley type having an intermediate pulley between a drive pulley and a driven pulley. Regarding

(Prior Art) Conventionally, as a pulley type continuously variable transmission provided with an intermediate pulley of this type, for example, one disclosed in Japanese Utility Model Publication No. 45-3212 is known. That is, this is a drive pulley supported by a drive shaft, a driven pulley supported by a driven shaft parallel to the drive shaft, and a rotation between a drive shaft and a driven shaft in a plane orthogonal to both shafts. It comprises an intermediate pulley rotatably supported by an intermediate portion of a possible arm via an intermediate shaft, and a pair of belts respectively wound around the drive and driven pulleys and the intermediate pulley. The intermediate pulley is slidably and rotatably supported by a pair of axially opposed fixed shave and an intermediate shaft between the fixed shave, and a pair of pulleys are provided between the fixed shave. Comprised of a movable shape of the abacus ball shape that forms the part,
By rotating the arm and moving the movable shave in the axial direction by the tension of the belt, the pulley diameters of both pulley portions are changed to change the rotation between the drive and driven pulleys.

However, this has a problem in that the belt slips. Therefore, as an improved technology,
According to Japanese Patent Laid-Open No. 45-14572, in the above-mentioned pulley type continuously variable transmission, a tensioner (tension pulley) for pressing one of the pair of belts on the loose side by the spring force of a spring is provided. The tensioner applies tension to the belt to suppress the slip.

(Problems to be solved by the device) However, in this proposal, on the other hand, the belt tension is applied by pressing the tensioner, and when the pulley diameter of each pulley part of the intermediate pulley increases or decreases in the opposite direction at the time of gear shifting. , The tensioner is displaced greatly. For this reason, there has been a problem that the amount of elongation of the spring for applying tension to the belt fluctuates greatly, the tension of each belt becomes unstable, and the transmission efficiency thereof decreases.

The present invention has been made in view of the above points, and an object thereof is to provide two belts with tensioners each having a dedicated tensioner so that two tensioners are provided and the two tensioners are linked. The purpose is to stabilize the tension of both belts and improve the transmission efficiency thereof regardless of the speed change state by making them movable.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the solution means of the present invention is to support both tensioners on a swingable link and to connect the both links by a spring.

That is, the present invention includes a drive pulley supported on a drive shaft, a driven pulley supported on a driven shaft parallel to the drive shaft, and an intermediate shaft parallel to the drive and driven shafts.
An intermediate pulley having first and second pulley portions, a first belt wound between the drive pulley and the first pulley portion of the intermediate pulley, and a second pulley of the driven pulley and the intermediate pulley. The intermediate pulley comprises a pair of first and second fixed sheaves facing each other in the axial direction and an intermediate shaft between the two fixed sheaves. It is slidably and rotatably supported, and has a substantially abacus-ball-shaped movable shape that forms the first and second pulley portions between the fixed shapes, and the movable shape in the axial direction of the movable shape. It is premised on a continuously variable transmission in which the pulley diameters of both pulley portions are changed in opposite directions by movement to change the rotation between the drive and driven pulleys.

In this continuously variable transmission, a first tensioner for pressing the back surface or the inner surface of the first belt to apply tension to the belt and a first tensioner parallel to the drive shaft, the driven shaft and the intermediate shaft. Of the first tensioner is rotatably supported by the support shaft of the first tensioner, and the first tensioner is rotatably supported at the end thereof, and the tensioner and the first support shaft are pressed when pressing the back surface of the belt of the first tensioner. And a first link having a spring engaging portion formed at a portion opposite to the first tensioner with respect to the first support shaft when pressing the inner surface of the belt.

On the other hand, the second tensioner for pressing the rear surface or the inner surface of the second belt to apply tension to the belt and the second support shaft that is parallel to the drive shaft, the driven shaft and the intermediate shaft are rocked. And a second tensioner rotatably supported at the end of the belt. When the second tensioner presses the back surface of the belt, an intermediate portion between the tensioner and the second support shaft is provided. In addition, when the inner surface of the belt is pressed, a spring engaging portion is formed on a portion of the second support shaft opposite to the second tensioner.
And link.

Further, a spring is provided between the spring engaging portions of the both links, and the pulley diameter of one of the pulley portions is increased by the movement of the movable shape of the intermediate pulley, and the spring is hung on the pulley portion. When one tensioner corresponding to one belt moves so as to be pushed by the one belt, both links are rotationally biased so that the other tensioner moves in a direction of pressing the other belt. To configure.

(Operation) With the above configuration, in the present invention, when the gear ratio of the transmission is changed, the movable shave in the intermediate pulley is moved in the axial direction. Due to the axial movement of the movable shave, the pulley diameters of the first and second pulley portions are increased / decreased in mutually opposite directions, whereby the gear ratio between the drive and driven shafts is variably adjusted. For example, when the movable shape is moved to the side of the first fixed shape, the pulley diameter of the first pulley portion becomes larger than that of the second pulley portion, and the rotation of the drive pulley is decelerated by the intermediate pulley to the driven pulley. It becomes a low speed state that is transmitted.

In that case, when the movable shape of the intermediate pulley moves, the pulley diameter of one pulley portion becomes larger than that of the other pulley portion, and when the tension of one belt hung on the pulley portion becomes high, it corresponds to the belt. One tensioner moves in the direction pushed by the one belt, and one link supporting the tensioner rotates about the support shaft, and the rotation of this link hangs the spring engagement portion. The spring is deformed. Then, this spring force causes the other link to rotate about the same support shaft, and the other tensioner supported by the link moves in a direction of pressing the other belt.

For example, when the first tensioner presses the inner surface of the first belt and the second tensioner presses the back surface of the second belt, the first tensioner presses the first support shaft against the first support shaft. A spring engaging portion is formed at the end opposite to the first tensioner, and a spring engaging portion is formed at the intermediate portion between the second support shaft and the second tensioner in the second link. Then, when the tension of the first belt increases and the first tensioner is pushed by the first belt, the first link rotates around the first support shaft and hangs on the end portion thereof. Extend the springs that are attached. Due to the restoring force of the spring in the contracting direction, the second link is pulled at the intermediate portion thereof, the link rotates about the second support shaft, and the second tensioner at the end portion thereof has the second belt. Move in the direction of pressing the back of the.

That is, since the spring rotates and contracts the other link by the amount pulled by the rotation of the one link, the tension applied to the belt by the spring hardly changes and is kept substantially constant. Therefore, the transmission efficiency can be improved and maintained by ensuring the stable tension of the belt.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the entire structure of a continuously variable transmission A according to an embodiment of the present invention, where 1 is a drive shaft which is an output shaft of an engine mounted on a combine as an agricultural machine, and 3 is the drive shaft 1 described above. Is a rotatable driven shaft that is arranged in parallel below the drive shaft, and the driven shaft 3 is a drive mechanism (not shown) of the combine.
Are linked to. Reference numeral 5 denotes an intermediate shaft which is arranged between the drive shaft 1 and the driven shaft 3 in parallel with both shafts 1, 3, and these shafts 1, 3, 5 are provided in a case (not shown) of the transmission A. It is rotatably supported. The drive shaft 1 has a drive pulley 2 which is a fixed pulley having a belt groove 2a having a V-shaped section, and the driven shaft 3 has a belt groove 4a having a V-shaped section which is offset from the drive pulley 2. The driven pulleys 4 made of fixed pulleys are mounted so as to rotate together and are not slidable, and the pulley diameter of the driven pulley 4 is set larger than that of the drive pulley 2. Reference numeral 30 is an idler pulley arranged above the driven pulley 2.

Further, an intermediate pulley 6 is supported on the intermediate shaft 5. As shown in FIG. 2, the intermediate pulley 6 includes a pair of first and second fixed sheaves 7 and 8 facing each other in the axial direction.
A pair of first and second pair of pulley portions 10 and 11 is slidably and rotatably supported by the intermediate shaft 5 between the fixed shapes 7 and 8 and is formed between the fixed shapes 7 and 8 in a pair. And a movable shape 9 having a substantially abacus ball shape. In addition, for example, three rod insertion holes (not shown) penetrating the vicinity of the boss portion are formed in the first fixed shape 7 at equal angular intervals in the circumferential direction. A first belt 12, which is a V-belt, is provided between the first pulley portion 10 and the belt groove 2a of the drive pulley 2, and the second pulley portion 11, the belt groove 4a of the driven pulley 4 and the idler pulley. A second belt 13, which is also a V-belt, is also wound between the first and second pulley portions 10 and 11 by the movement of the movable shave 9 in the axial direction. The diameter is increased / decreased in opposite directions, and the rotation is continuously changed between the driving and driven pulleys 2 and 4.

Further, the movable shape 9 of the intermediate pulley 6 moves the movable shape 9 in the axial direction to drive and drive the driven pulleys 2,4.
It is connected to a speed change mechanism 14 for changing the rotation speed.
The speed change mechanism 14 is a cylindrical cam that is fixed to a case as a fixed body so as to surround the intermediate shaft 5.
The cam 15 is provided with a pair of cam grooves 16, 16 (only one is shown) horizontally extending through the inside and outside of the cam 15 so as to face each other in the horizontal direction.

Further, for example, three rods 17, 17, ... Which axially penetrate the first fixed shape 7 through the rod insertion holes are integrally fixed to the movable shape 9 at the inner end. The outer ends of 17, 17, ... Are integrally formed into a ring portion (not shown), and the cam follower 18 is supported on the ring portion so as to be relatively rotatable and slid integrally through a bearing (not shown), On the outer circumference of this cam follower 18, the above-mentioned cam 15
A roller 19 that fits into each cam groove 16 and rolls is rotatably supported. Further, an operation lever 20 is attached to the upper part of the outer periphery of the cam follower 18.

The cam follower 18 is operated by operating the operation lever 20.
By rotating the roller about the intermediate shaft 5, the roller 19
The cam follower 18 while rolling in the cam groove 16 of the cam 15.
Is moved in the axial direction to move the movable shave 9 connected to the cam follower 18 through the bearings and the rods 17, 17, ... In the axial direction, and the operation lever 20 is rotated to, for example, the low speed position on the drive pulley 2 side. When the moving operation is performed, the movable shape 9 is moved to the second fixed shape 7 side so that the pulley diameter of the first pulley portion 10 is smaller than that of the second pulley portion 11 to rotate the drive pulley 2. The intermediate pulley 6 decelerates and the low speed state is transmitted to the driven pulley 4. on the other hand,
When the operation lever 20 is reversely rotated to the high speed position on the driven pulley 4 side, the movable shape 9 is moved to the first fixed shape 7 side and the pulley diameter of the second pulley portion 11 is set to the first value.
By making it smaller than the pulley portion 10, the rotation speed of the drive pulley 2 is increased by the intermediate pulley 6 and is transmitted to the driven pulley 4 in a high speed state.

Further, as shown in FIG. 1, in the case above the drive shaft 1, a first link 21 is provided in a vertical plane by a first support shaft 22 parallel to the drive shaft 1 (driven shaft 3) at an intermediate portion thereof. One end of the link 21 (end on the intermediate shaft 5 side) is swingably supported by
An idler pulley 23 as a first tensioner for pressing the inner surface of the first belt 12 on the slack side to apply tension to the belt 12 is rotatably supported via a support pin 24. .

On the other hand, in the case below the driven shaft 3, a second link 25 is supported at one end thereof by a second support shaft 26 parallel to the driven shaft 3 (driving shaft 1) so as to be swingable in the vertical plane. The link 25
The other end (the end on the side of the intermediate shaft 5) of the second belt
A tension roll 27 as a second tensioner for pressing the back surface of the loose side 13 to apply tension to the belt 13 is rotatably supported via a support pin 28.

A first spring engaging hole 21a is formed through the other end of the first link 21, one end of a tension spring 29 is locked in the engaging hole 21a, and the other end of the spring 29 is The second link 25 is locked in a second spring engagement hole 25a formed through the middle portion of the second link 25.
A spring 29 is extended between the spring engagement holes 21a and 25a. Then, due to the tension spring force of this spring 29, the pulley diameter of, for example, the first pulley portion 10 increases due to the movement of the movable shave 9 of the intermediate pulley 6, and the first belt 12 hung on the pulley portion 10 is changed. When the corresponding idler pulley 23 is pushed by the first belt 12 and moves from the high speed position (Hi) shown by the phantom line in FIG. 1 to the solid low speed position (Lo), the tension roll 27 moves to the second position. The links 21 and 25 are rotationally biased so as to move in the direction of pressing the belt 13.

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

First, when the transmission A is switched to the low speed state, the operation lever 20 of the speed change mechanism 14 is positioned at the low speed position.
By this switching operation of the operation lever 20, the cam follower 18 integrated with the lever 20 rotates in one direction, and by this rotation,
A roller 19 on the outer periphery of the cam follower 18 rolls in the cam groove 16 of the cam 15, and the cam follower 18 moves along the axial direction, for example, in the second direction.
Move to the right in the figure. The axial movement of this cam follower 18 causes the bearing and rod 1
The movable shave 9 of the intermediate pulley 6 connected via 7, 17, ... Moves toward the first fixed shave 7, and the pulley diameter of the first pulley portion 10 is larger than that of the second pulley portion 11. Become. As a result, the rotation of the drive pulley 2 is decelerated and transmitted to the intermediate pulley 6, and the rotation of the intermediate pulley 6 is decelerated and transmitted to the driven pulley 4, so that the rotation of the drive shaft 1 is decelerated at a large reduction ratio. Is transmitted to the driven shaft 3 and the transmission A is decelerated.

At that time, as the diameter of the first pulley portion 10 of the intermediate pulley 6 becomes larger than that of the second pulley portion 11 due to the movement of the movable shape 9 toward the first fixed shape 7 side, the pulley diameter becomes larger. , The first belt 12 hung on the first pulley portion 10 tries to be tensioned, and the second belt 13 hung on the second pulley portion 11 having a smaller pulley diameter tries to loosen the belt. . Then, due to the tension of the first belt 12, the idler pulley 23 contacting the belt 12 is
The first link 21 is pushed in the direction toward the low speed position (Lo) from 12 and rotates clockwise in FIG.
By the rotation of, the spring 29 hooked in the spring engagement hole 21a is pulled, and the spring force thereof is increased. Since the other end of the spring 29 is hooked on the spring engaging hole 25a in the middle portion of the second link 25, the second link 25 is pulled by the increased spring force of the spring 29, and is rotated counterclockwise in the figure. The second belt 13 is rotated in this direction, and the tension roll 27 at the tip of the link 25 is pushed in the direction toward the low speed position (Lo) by the rotation of the link 25 so that the second belt 13 tries to relax.
, Which causes the tension of the second belt 13 to increase above a predetermined level.

On the other hand, conversely, when the transmission A is switched to the high speed state, the operation lever 20 is positioned at the high speed position. By this switching operation, the cam follower 18 rotates in the other direction,
The engagement of the roller 19 with the inside of the cam groove 16 on the outer periphery of the cam 15 causes the cam follower 18 to move leftward in FIG. By this movement, the movable shape 9 of the intermediate pulley 6 moves to the second fixed shape 8 side, and the pulley diameter of the first pulley portion 10 becomes smaller than that of the second pulley portion 11. As a result, the rotation of the drive pulley 2 is accelerated and transmitted to the intermediate pulley 6, and the rotation of the intermediate pulley 6 is accelerated and transmitted to the driven pulley 4, so that the rotation of the drive shaft 1 is increased by a large acceleration ratio. Is transmitted to the driven shaft 3 and the transmission device A is put into an accelerated state.

At that time, similarly to the above, as the pulley diameter of the second pulley portion 11 of the intermediate pulley 6 becomes larger than that of the first pulley portion 10, the second pulley portion 11 is hung on the second pulley portion 11 by the second diameter. The belt 13 of the first belt 12 tries to be tensioned, and the first belt 12 hung on the first pulley portion 10 tries to loosen, but the tension of the second belt 13 causes the tension roll contacting the belt 13. 27 is pushed in the direction toward the high speed position (Hi) by the second belt 13, the second link 25 is rotated clockwise in FIG. 1, and the rotation of this link 25 pulls the spring 29. , Its spring force increases. Due to the increased spring force of the spring 29, the first link 21 is pulled and rotated in the counterclockwise direction in the drawing, and the rotation of this link 21 causes the idler pulley 23 at one end thereof to move toward the high speed position (Hi). The first belt 12 which is pushed in the direction and relaxed is pressed, and the tension of the first belt 12 is secured.

Therefore, when the gearbox of the transmission A is thus shifted, the spring 29 rotates and contracts the other link 25 (or 21) by the amount pulled by the rotation of the one link 21 (or 25). Belt 13 by 29 (or 1 by
The tension applied to 2) hardly changes and is kept substantially constant, so that the belts 12 and 13 are always kept at proper tensions.
As a result, stable transmission of the tension of the belts 12 and 13 can improve and maintain the transmission efficiency.

In the above embodiment, the cam 15 of the gear change mechanism 14 is fixed to the case, and the roller engaging with the cam groove 16 of the cam 15 is used.
Although the cam follower 18 having 19 is connected to the movable shape 9 of the intermediate pulley 6, conversely, the cam may be connected to the movable shape 9 and the cam follower may be fixed to the case, and the same effect as the above-described embodiment is obtained. be able to.

In the above embodiment, the idler pulley 23 as the first tensioner is on the inner surface of the first belt 12, and the tension roll 27 as the second tensioner is the second belt 13.
The idler pulley 23 may press the back surface of the first belt 12 and the tension roll 27 may press the inner surface of the second belt 13, respectively. In that case, a first spring engaging hole 21a is formed in the middle portion of the first link 21, and a second link 2 is formed.
It suffices to extend 5 to the side opposite to the tension roll 27, form second spring engagement holes 25a at the ends thereof, and extend the spring 29 between these spring engagement holes 21a, 25a.

Further, both the idler pulley 23 and the tension roll 27 may press the back surface (or inner surface) of the belt. In that case, spring engaging holes 21a and 25a are formed in the intermediate portions (or end portions) of the links 21 and 25, and a spring 29 is extended between these spring engaging holes 21a and 25a.

Further, the present invention can be applied not only to the combine as in the above embodiment, but also to a transmission having a relatively low load transmission capability such as another agricultural machine such as a harvester, a lawn mower, and a snowplow transmission. Needless to say.

(Effects of the Invention) As described above, according to the present invention, the drive and driven pulleys, the intermediate pulley having a pair of pulley portions with variable pulley diameters, arranged between the pulleys, and the pulleys and the intermediate pulleys. In a pulley type transmission including a pair of belts that are respectively wound between pulley parts, tensioners for applying tension to both belts are supported by swingable links, and a spring is provided between the two links. Erection,
By this spring, the pulley diameter of one pulley portion is increased by moving to the movable shape of the intermediate pulley, and one tensioner corresponding to one belt hung on the pulley portion is moved in the direction pushed by the belt. sometimes,
By urging both links to rotate so that the other tensioner moves in the direction that presses the other belt, the spring is pulled by the rotation of one link during gear shifting, so that the other link is pulled. By rotating and contracting, the tension applied to the belt by the spring can be kept stable, and thus the transmission efficiency of the belt in the transmission can be improved and maintained.

[Brief description of drawings]

1 is a front view schematically showing a transmission, and FIG. 2 is a side view showing an intermediate pulley and a gear change mechanism. A ... transmission, 1 ... engine drive shaft, 2 ... drive pulley, 3 ... driven shaft, 4 ... driven pulley, 5 ... intermediate shaft, 6 ... intermediate pulley, 7 ... first fixed Shave, 8
...... Second fixed shape, 9 ...... Movable shape, 10 ......
1st pulley part, 11 ... 2nd pulley part, 12 ... 1st belt, 13 ... 2nd belt, 14 ... Shift-change mechanism, 21
...... First link, 21a ...... First spring engagement hole, 22
...... First support shaft, 23 ...... Idler pulley (first tensioner), 25 ...... Second link, 25a ...... Second spring engaging hole, 26 ...... Second support shaft, 27 ...... Tension roll (Second tensioner), 29 ... Spring.

Claims (1)

[Scope of utility model registration request] 1. A drive pulley supported by a drive shaft, a driven pulley supported by a driven shaft parallel to the drive shaft, and an intermediate shaft parallel to the drive and driven shafts. An intermediate pulley having two pulley portions, a first belt wound between the drive pulley and the first pulley portion of the intermediate pulley, and the driven pulley and the second pulley portion of the intermediate pulley. With a second belt wrapped between
The intermediate pulley has a first and a second axially opposed first pulley.
Substantially abacus ball shape that is slidably and rotatably supported by a pair of fixed shapes and an intermediate shaft between the fixed shapes, and that forms the first and second pulley portions between the fixed shapes. A continuously variable transmission having a movable shape and a movable shape, and by changing the movable shape in the axial direction, the pulley diameters of both pulley portions are changed in opposite directions to change the rotation between the drive and driven pulleys. In, the first tensioner for pressing the back surface or the inner surface of the first belt to apply tension to the belt and the first support shaft parallel to the drive shaft, the driven shaft and the intermediate shaft can be swung. When the first tensioner presses the back surface of the belt, the first tensioner is rotatably supported at its end, and the first tensioner is rotatably supported at the intermediate portion between the tensioner and the first support shaft. , Again press the inner surface of the belt It shall be when it first spring engaging portion respectively on the opposite side portion and the first tensioner with respect to the first support shaft is provided
Link, a second tensioner for pressing the back surface or the inner surface of the second belt to apply tension to the belt, and a second support shaft parallel to the drive shaft, the driven shaft, and the intermediate shaft. When the second tensioner is movably supported, and the second tensioner is rotatably supported at the end, and the second tensioner presses the back surface of the belt, an intermediate portion between the tensioner and the second support shaft. And a second engaging shaft for pressing the inner surface of the belt, a second engaging portion is provided with a spring engaging portion at a portion opposite to the second tensioner.
And the spring engaging portions of the both links, and the movable diameter of the intermediate pulley causes the pulley diameter of one of the pulleys to increase, so that one of the belts hung on the pulley is A spring for urging both links so that when the corresponding one tensioner moves so as to be pushed from the one belt, the other tensioner moves in a direction to push the other belt. A continuously variable transmission characterized by: