JPH0529570Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a pulley that changes the diameter of each of a pair of variable pulleys around which a transmission belt is wound, thereby making the speed ratio between the two pulleys variable. This invention relates to improvements in transmissions.

(Prior Art) This type of pulley type transmission has been widely used in relatively low-load power transmission systems, such as transmissions in agricultural machinery and vehicles. This transmission has, for example, a pair of variable pulleys (driving and driven pulleys) respectively attached to a pair of rotating shafts arranged parallel to each other, and each pulley is rotatably integral with the rotating shaft and slides. a fixed sheave that is fixed irremovably; and a movable sheave that is rotatably and slidably supported on a rotating shaft and that forms a belt groove with a V-shaped cross section around which a transmission belt is wound. By changing the pulley diameter (effective radius of the belt groove) by moving the movable sheave toward and away from the fixed sheave using a speed change mechanism,
The gear ratio between both rotating shafts is switched from a low speed state to a high speed state.

(Problem to be solved by the invention) As a method of linking the movable shafts of the drive and driven pulleys and sliding them in the axial direction, the speed change mechanisms of both pulleys are both constructed with a cam mechanism, and one of them is equipped with a speed change mechanism. A method in which the operating lever is directly fixed and the cam mechanism of the other pulley is connected to the cam mechanism of one pulley by a link, or a method in which the movable sheave of the drive pulley is driven by a flyweight and the movable sheave of the driven pulley is moved by a spring. There is a method in which the movable shafts of both the drive and the drive pulley are driven by springs, one of which is driven by a control lever, and the other driven by a ring.

By the way, when such a pulley-type transmission is installed in agricultural machinery, etc., the engine is usually supported by a mount on the vehicle body, and a drive pulley is attached thereto, with its output shaft serving as one rotational shaft. on the other hand,
The other rotating shaft is directly supported on the vehicle body side, and a driven pulley is attached to the rotating shaft.

In that case, since the vibration systems on the driving side (engine side) and driven side (vehicle body side) are different, the above
In either method, the vibrations of the engine mounted on the mount are transmitted to the transmission mechanism of the driven pulley, causing the drive pulley and driven pulley to move differently, causing the pulley to open and close, resulting in a constant transmission ratio. The condition is not stable, and as a result, there are problems such as premature wear of the sliding parts of the pulleys, an increase in heat generation due to radial fluctuation of the belt, and a decrease in its durability.

The purpose of the present invention is to suppress the vibration of one pulley from being transmitted to the other pulley even if the vibration systems of the driving and driven pulleys are different by using the above-mentioned mount. The purpose is to eliminate the opening and closing of the pulley due to transmission, thereby suppressing wear on the pulley sliding part and improving the durability of the belt.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides means for absorbing vibrations in a mechanism that varies the pulley diameters of the driving and driven pulleys in conjunction with each other.

That is, the invention according to claim (1) includes a pair of rotating shafts arranged parallel to each other, a fixed shaft fixed to each rotating shaft in a rotationally integral manner and immovable in the axial direction, and each rotating shaft. a pair of variable pulleys consisting of a movable sheave that is rotatably and movably supported in the axial direction and that forms a belt groove with a V-shaped cross section between it and the fixed sheave; and a belt groove between the two variable pulleys. A power transmission belt is provided.

Furthermore, it has a cylindrical rotating cam that is rotatable around a rotation axis and a fixed cam that makes cam contact with the rotating cam, and a cam surface is formed on at least one of the rotating cam or the fixed cam. a pair of transmission mechanisms that move the movable sheave of each of the variable pulleys in the axial direction to move toward and away from the fixed sheave by rotation and relative rotation of the fixed cam, thereby changing the pulley diameter of the variable pulley; It is composed of a straight rod-shaped link connected to the rotary cam of one of the transmission mechanisms, and a ball joint connected to the rotation cam of the other transmission mechanism and slidably supported by the link. A speed change switching mechanism is provided which interlocks the two speed change mechanisms so that the pulley diameters of the variable pulleys change in opposite directions to vary the speed ratio between the two rotating shafts.

The transmission switching mechanism includes a spring disposed between the ball joint and the link to limit relative movement between the two, and a buffer means for absorbing vibrations transmitted between the two transmission mechanisms. composition.

In the device described in claim (2), the direction of the movable sheave of one variable pulley toward the fixed sheave and the direction of the movable sheave of the other variable pulley toward the fixed sheave are opposite to each other, so that the movable sheave of each variable pulley is is rotatably and movably supported in the axial direction on each rotating shaft at its boss portion.

Further, a cam surface is formed on one of the rotary cam or the fixed cam, and a roller is provided on the other that rolls into contact with the cam surface.

Further, the rotary cam is supported on the outer periphery of the boss part of the movable shaft via a bearing so that it can move integrally in the axial direction and can rotate relative to the rotary shaft, while the fixed cam is immovable in the axial direction and can rotate relative to the rotating shaft. shall be.

(Operation) With the above configuration, the device according to claim (1),
By the switching operation of the speed change switching mechanism, the speed change mechanisms of both variable pulleys are operated in conjunction with each other, the pulley diameters of both variable pulleys are changed in mutually opposite directions, and the speed change ratio between both rotating shafts is switched. Specifically, when the rotary cam in the transmission mechanism is rotated about the rotation axis with respect to the fixed cam, the movable shaft moves in the axial direction due to the relative rotation between the two cams, and the pulley diameter changes. In this way, when the transmission mechanism of one variable pulley operates, the movement is transmitted to the transmission mechanism of the other pulley via the link and the ball joint supported by the link, thereby causing both pulleys to move relative to each other. They can be opened and closed together.

At this time, at the beginning of the gear change, the link and the ball joint transiently move relative to each other while expanding and contracting the spring between them, but in a steady state, the spring returns to its original state and the gear ratio becomes stable.

In a steady state where the gear ratio is constant, if the vibration systems of both variable pulleys are different from each other, the vibration of one variable pulley will be transmitted to the other pulley through the link and ball joint of the gear change mechanism. However, since the speed change mechanism is equipped with a spring as a shock absorbing means for absorbing vibrations, the vibration causes the link and ball joint to move relative to each other, causing the spring to expand and contract, and due to the damping of this spring. As a result, vibrations are absorbed and transmission of vibrations to the other pulley is suppressed. Therefore, opening and closing due to vibration of the variable pulley can be eliminated, and the gear ratio can be stabilized in a steady state.

In this case, since the link is in the shape of a straight rod, the space for arranging the speed change switching mechanism is small, and its layout can be simplified. Therefore, it is possible to both simplify the arrangement and layout of the speed change switching mechanism and to suppress vibration transmission by using the straight rod-shaped link.

In addition, regarding the action of the device stated in claim (2),
This will be explained with reference to FIGS. That is, in this invention, as shown in FIGS. 1 and 2, when switching the gear ratio between both rotating shafts 3 and 6, each transmission mechanism 2 consisting of a cam mechanism of both variable pulleys 10 and 16 is used.
Since the rotary cams 24 and 32 in 2 and 30 are interlockably connected by a speed change switching mechanism 48 having one link 41, one pulley 10
or 16 transmission mechanisms 22 or 30 rotating cams 24
Or, when the movable sheave 13 or 19 of the pulley 10 or 16 is moved in the axial direction by rotating the movable sheave 13 or 19 of the pulley 10 or 16 due to its cam contact with the fixed cam 27 or 37, the other The movable sheave 19 or 13 of the pulley 16 or 10 moves in a manner opposite to the movement of the movable sheave 13 or 19 in the one pulley 10 or 16 toward and away from the fixed sheave 12 or 18, and both movable sheaves 13, 19 in the opposite direction, the gear ratio between both rotating shafts 3 and 6 is changed.

At that time, as shown in FIGS. 3 and 4, for example, the rotary cam 2 in each transmission mechanism 22, 30
4, 32 have cam surfaces 24a, 32a inclined at an inclination angle α with respect to a plane orthogonal to the rotating shafts 3, 6, and fixed cams 27, 37 have rolling elements 29, which roll on the cam surfaces 24a, 32a. 39 is provided, the rolling elements 29 on the fixed cams 27, 37,
39 to the cam surfaces 24a, 3 of the rotating cams 24, 32
A force A acts on the cam surface 2a in a direction perpendicular to the cam surfaces 24a and 32a, and this force A is divided into a component force A1 in a direction parallel to the rotation axes 3 and 6 and a component force A2 in a direction perpendicular to the rotation axes 3 and 6. The latter component force A2 acts at right angles to the line connecting the axes of the rotating shafts 3 and 6 and the connection point to one link 41 of the speed change switching mechanism 48. As shown in FIG.
Perpendicular and above component force A2 regardless of the change of Lo to Hi
A cam rotation reaction force W in the opposite direction is generated. In the case of the device described in claim (2), the rotating cams 24, 3
2 is the boss portion 13a, 1 of the movable shaft 13, 19.
Since the cam rotation reaction force W is supported on the rotating cam 2a, as shown in FIG.
4, 32 are supported
For the boss portions 13a, 19a of 9, the pulleys 10,
It acts to press the boss portions 13a, 19a at the center position of the range where the belt B of 16 is wound. In other words, the boss portions 13a, 19
The cam rotation reaction force W against a is the boss portion 13a, 1
9a and the sliding portion of the rotating shafts 3, 6, when the movable shaves 13, 19 receive thrust from the belt B, a moment M1 acts in the direction of tilting the movable shaves 13, 19 with respect to the rotating shafts 3, 6. This acts to generate a moment M2 in the opposite direction, and this moment M2 cancels out the moment M1 and reduces it, so that the boss portions 13a, 19 of the movable sheaves 13, 19 as shown in FIG. 5a.
The surface pressure distribution on the inner circumference of the rotating shafts 3 and 6 on the outer circumference of the rotating shafts 3 and 6 is dispersed in the axial direction, and the large peak as in the conventional case (see Fig. 5b) is eliminated, and the boss portions 13a and 19
The sliding resistance of a becomes smaller. As this sliding resistance becomes smaller, the rotational cam 2 of the belt-generated thrust F is
Load applied to the fixed point by 4, 32 (extraction thrust
In other words, the thrust force F generated by the belt is transmitted to the rotary cams 24, 32 as the extraction thrust F' without significant resistance.

In the transmission, the rotating cams 24 of both transmission mechanisms 22 and 30 are arranged so that the opening and closing forces between the variable pulleys 10 and 16 are reversed and the opening and closing forces between both pulleys 10 and 16 partially cancel each other out. , 32 are connected by one link 41, and the output thrust F1' or F2' of one transmission mechanism 22 or 30 is used for the belt thrust of the other transmission mechanism 30 or 22. If the relationship is likened to a seesaw as shown in Fig. 6, when the gear ratio is constant and no gear change is performed, as shown in Fig. 7, the extracted thrusts F1' and F2' themselves are (see Figure 7a) is larger than the conventional case (see Figure 7b), but the extraction thrust F on the driving side and driven side
1' and F2' are the same, and these balance each other, so that the extraction efficiency of thrust forces F1' and F2' is the same as in the conventional case.

However, when changing the gear ratio, the eighth
As shown in the figure, the difference between the belt-generated thrusts F1, F2 and the extraction thrusts F1', F2' is the load (operating force) required for the gear shifting operation, so in the conventional case (see Figure 8b), the extraction Whereas the remaining operating force increases as the thrust forces F1' and F2' are smaller, in this design (see Figure 8a), the output thrust forces F1' and F2' are large, so the operating force increases accordingly. This means that less force is required. As a result, the rotating cams 24, 3
2 and the fixed cams 27, 37 come into contact with each other via the rolling elements 29, 39, and the speed change between the two rotary shafts 3, 6 can be quickly performed with a small operating force. It is possible to quickly deal with the situation.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIGS. 1 and 2 show the overall configuration of an embodiment in which the present invention is applied to a transmission device for agricultural machinery. 1 is a first rotating shaft rotatably supported by a bearing part (not shown);
The bearing portion is elastically supported by a mount on the vehicle body of the agricultural machine together with a vehicle-mounted engine (not shown). A second rotating shaft 2 is rotatably supported by a bearing fixed to the vehicle body, and is connected to an axle (not shown) of the agricultural machine. Both rotating shafts 1 and 2 are arranged parallel to each other. A drive shaft 3 is attached to the first rotating shaft 1 so as to rotate integrally therewith. That is, this drive shaft 3 has a center hole 3.
a is formed through the center hole 3a, and the first rotating shaft 1 is inserted from one end side (the upper side in FIG. 2) of the drive shaft 3 into the center hole 3a.
The drive shaft 3 is rotatably attached to the first rotary shaft 1 by inserting the fastening bolt 5 from the other end of the drive shaft 3 to the end of the rotary shaft 1 via the stopper 4. ing.

Further, a driven shaft 6 is rotatably attached to the second rotating shaft 2 with the same mounting structure as the drive shaft 3 described above. That is, the rotating shaft 2 is inserted into the center hole 6a of the driven shaft 6 from one end side (lower side in FIG. 2), and the fastening bolt 8 is inserted into the rotating shaft 2 from the other end of the driven shaft 6 via the stopper 7. The driven shaft 6 is attached to the second rotating shaft 2 by screwing and fastening the end portion thereof.

A V-pulley 9 is rotatably fixed to the other end of the drive shaft 3 (the end opposite to the first rotating shaft 1), and this V-pulley 9 is drivingly connected to the engine via a V-belt (not shown). , a drive shaft 3 (first rotating shaft 1) is driven by the rotation of the engine. Also,
A drive pulley 10 is provided at one end of the drive shaft 3. This drive pulley 10 includes a flange-shaped fixed sheave 12 that is rotatably and non-slidably fixed to the drive shaft 3 by a key 11, and a boss portion 13a that is attached to the drive shaft 3 so as to face the fixed sheave 12.
A belt groove 15 is formed between these two shafts 12 and 13.

On the other hand, a driven pulley 16 is provided on the driven shaft 6. This driven pulley 16 has the same configuration as the driving pulley 10 described above, and includes a flange-shaped fixed sheave 18 that is rotatably and non-slidably fixed to the driven shaft 6 by a key 17, and a flange-shaped fixed sheave 18 that is fixed to the driven shaft 6 by a key 17 to drive the drive pulley 10. The drive pulley 10 on the shaft 3 is slidably and rotatably connected to the driven shaft 6 by a key 20 so as to be opposed to the fixed sheave 12 in the opposite direction. It consists of a flange-shaped movable sheave 19, and both these sheaves 18,1
A belt groove 21 is formed between the belt grooves 9 and 9. A V-belt B is wound between the belt groove 15 of the drive pulley 10 and the belt groove 21 of the driven pulley 16.
Each of the 16 movable sheaves 13 and 19 is moved toward and away from the fixed sheaves 12 and 18, respectively, to change the pulley diameter (effective radius with respect to the V-belt B) of each pulley 10 and 16. For example, when the movable sheave 13 of the drive pulley 10 is brought close to the fixed sheave 12 and the movable sheave 19 of the driven pulley 16 is separated from the fixed sheave 18, the drive pulley 1
By making the diameter of the pulley 0 larger than that of the driven pulley 16, the rotation of the drive shaft 3 is transmitted to the driven shaft 6 at an increased speed. On the other hand, conversely, the movable sheave 13 of the drive pulley 10 is separated from the fixed sheave 12,
When the movable sheave 19 of the slave pulley 16 approaches the fixed sheave 18, the drive pulley 1
By reducing the diameter of the pulley 0 and increasing the diameter of the driven pulley 16, the rotation of the drive shaft 3 is decelerated and transmitted to the driven shaft 6.

On the drive shaft 3, a first cam mechanism 2 is provided as a speed change mechanism for moving the movable sheave 13 of the drive pulley 10 toward and away from the fixed sheave 12.
2 is provided. This cam mechanism 22 has a bearing 23 mounted on the boss portion 13a of the movable shaft 13.
The cam 24 has a cylindrical cam 24 as a cylindrical rotary cam that is externally fitted and supported so as to be relatively rotatable and axially movable through the cam 24. A pair of inclined cam surfaces 24a,
24a are formed at equal intervals (180° intervals) in the circumferential direction, and a rotary lever 25 is rotatably protruded from the outer periphery. Further, on the outer periphery of the other end of the drive shaft 3, a roller mount 27 constituting a fixed cam is supported so as to be relatively rotatable via a bearing 26, and the roller mount 27 is attached to a fixed body such as a transmission case C. It is fixed non-rotatably via a flange (not shown). A pair of pins 28 extending in the radial direction are provided on the outer periphery of the roller mounting base 27.
28 are attached at equal intervals in the circumferential direction. The head side of each pin 28 is a roller mounting base 2.
7, and the above-mentioned cam 2 is attached to the protruding part.
A cam roller 29 that rolls in contact with each cam surface 24a of No. 4 is rotatably supported.

On the other hand, a second cam mechanism 30 is provided on the driven shaft 6 as a speed change mechanism for moving the movable shaft 19 of the driven pulley 16 toward and away from the fixed shaft 18 . The second cam mechanism 30 has the same configuration as the first cam mechanism 22, and is rotatably and non-slidably externally fitted and supported on the boss portion 19a of the movable shaft 19 via a bearing 31. It has a cylindrical cam 32 as a cam, and this cam 32
A pair of inclined cam surfaces 32a, 32a are formed at equal intervals in the circumferential direction on the end surface opposite to the drive pulley 16, and a rotation lever 33 is rotatably attached to the outer periphery of the cam surfaces 32a. An operating lever mounting member 34 is attached to the tip of the rotating lever 33 with bolts 35, 3.
5, and the tip of the mounting member 34 is connected to an operating lever (not shown). Further, a roller mount 37 (cam follower) as a fixed cam is supported on the outer periphery of the other end of the driven shaft 6 via a bearing 36, and the roller mount 37 is fixed to the case C described above and cannot rotate. ing.
A pair of pins 38, 38 extending in the radial direction are attached to the outer periphery of the roller mount 37 at equal intervals in the circumferential direction, and the protruding portion of each pin 38 from the roller mount 37 has the above-mentioned A cam roller 39 that comes into contact with each cam surface 32a of the cam 32 is rotatably supported.

Then, the rotary lever 2 of the first cam mechanism 22 is
5 A ball joint 40 is attached to the shaft portion 40 at the tip.
It is rotatably supported at point a with a rotation center parallel to the drive shaft 3. The ball joint 40 has a link insertion hole 40b, into which one end of a straight bar-shaped link 41 is slidably inserted. A pair of spring stoppers 42, 42 are immovably fixed to this link 41 on both sides of the ball joint 40. Each spring stopper 42 has a nut 43 inserted into the link 41 and a screw 44 screwed into the nut 43. By screwing in the screw 44, the nut 43 is fixed to the link 41 in a non-slidable manner. There is. Further, on the links 41 on both sides of the ball joint 40, ring-shaped spring retainers 45, 45 are attached to the ball joint 40, respectively.
A coil spring 46 is compressed between each spring presser 45 and a corresponding spring stopper 42, and the extension force of the pair of springs 46 causes the ball joint to 40
is balanced and biased at a central position between both spring stoppers 42, 42. The link 41 extends toward the driven shaft 6, and its other end is rotatably connected to the operating lever mounting member 34 via a link ball 47 about a rotation center parallel to the driven shaft 6. Therefore, the ball joint 40, link 41, springs 46, 46
etc., the cams 24, 32 in each cam mechanism 22, 30 are linked to each other in response to the switching operation of the operating lever, and the boss portion 13 of the movable shakes 13, 19 is
a, rotate around 19a, and rotate the cam surface 24a,
By rolling the cam rollers 29, 39 on the cam rollers 32a, the movable sheaves 13, 19 are moved in the axial direction to move toward and away from the fixed sheaves 12, 18 in opposition to each other, and the belt grooves 15, 21 are moved. A speed change switching mechanism 48 is configured in which the effective radius, that is, the pulley diameter of the pulleys 10 and 16 is made variable, and the speed ratio between the two rotating shafts 3 and 6 is changed.

Further, the springs 46, 46 are biased to limit relative movement of the ball joint 40 with respect to the link 41, thereby absorbing vibrations transmitted between the cam mechanisms 22, 30 (transmission mechanism). A buffer means is configured.

In addition, the movable sheave 13 in the fixed sheave 12, 18 of the driving and driven pulleys 10, 16
Belt grooves 15 and 2 are provided on the surface opposite to belt groove 19, respectively.
Cylindrical ring parts 12a and 18a as belt regulating means, which extend concentrically with the drive and driven shafts 3 and 6 toward the movable shafts 13 and 19, are integrally protruded at predetermined positions on the inner peripheral edge corresponding to the bottom part of the belt. It is set up. On the other hand, annular grooves 13b and 19b as annular recesses are formed on the faces of the movable shaves 13 and 19 facing the fixed shaves 12 and 18, respectively.
18a, and when the movable shaves 13, 19 approach the fixed shaves 12, 18, the ring portions 12a, 18a are formed in the annular grooves 13b, 18a.
19b.

In FIG. 1, reference numeral 49 denotes a tension pulley that presses the back surface of the slack side of the belt B to apply a predetermined tension to the belt B. This pulley 49 is rotatably supported at the tip of a tension arm 50 that is pivotally supported on the case C of the transmission.
1 by a spring 51 stretched between the middle portion of the arm 50 and the case C, and the tension pulley 49 is pressed against the back surface of the belt B by the biasing force of the spring 51.

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

For example, when setting the engine to a low speed state where the rotation is decelerated and transmitted to the axle, the speed change switching mechanism 48
Position the control lever in the low speed position Lo. This operating lever is connected to the cam 32 in the second cam mechanism 30.
Since it is connected to the rotary lever 33 on the outer periphery via the mounting member 34, when the cam 32 is switched to the low speed position Lo, the cam 32 rotates each cam roller 39 on its cam surface 32a. The driven pulley 16 rotates in one direction around the boss portion 19a of the movable sheave 19. As a result, the cam surface 32a
is pushed by the roller 39 and the cam 32 moves downward on the driven shaft 6 in FIG. approach. As a result, the driven pulley 16 closes and its pulley diameter increases, and this increase in pulley diameter draws the V-belt B toward the driven pulley 16.

Further, since the rotary lever 25 is drivingly connected to the mounting member 34 via a link 41 and a ball joint 40, the operating lever can be moved to a low speed position.
With the switching to Lo, the cam 24 of the first cam mechanism 22 moves in the same direction as the cam 32 of the second cam mechanism 30 on the drive shaft 3 in synchronization with the movement of the movable shake 19 of the driven pulley 16. Rotate. This rotation of the cam 24 eliminates the pressure on the cam roller 29. Therefore, due to the tension of the belt B moving toward the driven pulley 16, the cam 24 and the movable sheave 13 connected thereto via the bearing 23 move away from the fixed sheave 12 (downward in the figure) toward the drive shaft 3. The driving pulley 10
opens and the pulley diameter decreases. As a result, the pulley diameter of the drive pulley 10 becomes smaller than that of the driven pulley 16, and the rotation of the drive shaft 3 is decelerated and transmitted to the driven shaft 6.

Conversely, in high-speed conditions where the engine rotation is increased and transmitted to the axle, the operating lever should be moved to the high-speed position.
Position it as Hi. With this switching operation of the operating lever, the cam 24 of the first cam mechanism 22 rotates in the other direction around the boss portion 13a of the movable sheave 13 on the drive pulley 10 while rolling the cam roller 29 on its cam surface 24a. Rotate. This cam 2
4, the cam surface 24a is rotated by the cam roller 29.
The movable sheave 13 also moves in the same direction and approaches the fixed sheave 12, thereby closing the drive pulley 10 and increasing the pulley diameter. . This increase in pulley diameter draws the V-belt B toward the drive pulley 10.

Further, in synchronization with the movement of the movable shake 13, the cam 32 of the second cam mechanism 30 rotates on the driven shaft 6 in the same direction as the cam 24, and the rotation of the cam 32 causes the cam roller to rotate. 39 is no longer pressed, and the tension of the belt B causes the driven pulley 1 to
The movable sheave 19 of No. 6 moves along with the cam 32 on the driven shaft 6 in a direction away from the fixed sheave 18 (upward in the figure). Due to the separation between the two sheaves 18 and 19, the driven pulley 16 opens and the pulley diameter decreases. As a result, the pulley diameter of the drive pulley 10 becomes larger than that of the driven pulley 16, and the rotation of the drive shaft 3 is accelerated and transmitted to the driven shaft 6.

In this embodiment, during the shift change as described above, the link 41 and the ball joint 40 temporarily move relative to each other while compressing one spring 46 and the other spring 46. However, when the steady state is reached, both springs 46, 46 return to their original length,
The ball joint 40 is held in a predetermined position by the balance between the springs 46, 46, and the gear ratio between the drive shaft 3 and the driven shaft 6 is held constant. In a steady state where the gear ratio is constant, the drive pulley 10 is supported on the engine side, and the driven pulley 16 is supported on the vehicle body side, and their vibration systems are different. Therefore, vibrations on the drive pulley 10 side, which is the engine side vibration system, The second cam mechanism 30 of the driven pulley 16, which is a vibration system on the vehicle body side, passes through the link 41 and the ball joint 40.
will be transmitted to That is, with the vibration, the link 41 moves relative to the ball joint 40, but this movement is caused by the springs 46, 46.
It will be attenuated by expanding and contracting. Therefore, due to the transmission of engine vibration, the second cam mechanism 30
The movable shaft 19 of the driven pulley 16 does not move in the axial direction due to a change in the operating state of the driven pulley 16, thereby eliminating unstable opening and closing of the driven pulley 16 and stabilizing the speed ratio in a steady state. As a result, the sliding part between the movable shaft 19 and the driven shaft 6 can be prevented from being worn out early, and the pulley 16 can be prevented from being worn out early.
Eliminates radial movement of belt B due to opening and closing of
The durability of belt B can be improved by suppressing the heat generation.

Further, in this case, since the link 41 has a straight bar shape, the space for arranging the speed change switching mechanism 48 is small, and its layout can be simplified. Therefore, it is possible to both facilitate the arrangement and layout of the speed change switching mechanism 48 and to suppress vibration transmission by employing the straight rod-shaped link 41.

In this embodiment, the slack side span of V-belt B is
By pressing the back surface of B ₁ with the tension pulley 49, tension is applied to the V-belt B, and this tension generates a belt thrust and also increases the movability of both the driving and driven pulleys 10 and 16. The shift switching mechanism 48 shifts the shift gears 13 and 19
Since it is moved in the axial direction by a mechanical drive, the opening and closing forces between the driving and driven pulleys 10 and 16 are opposite, and the opening and closing forces between the two pulleys 10 and 16 partially cancel each other out, and the remaining becomes the operating force.

When the speed ratio between the drive and driven shafts 3 and 6 is changed by moving the movable shafts 13 and 19 of both pulleys 10 and 16 in the opposite direction in this way, as shown in FIGS. 3 and 4. As shown, the cam surfaces 24a, 32a of the cylindrical cams 24, 32 of each cam mechanism 22, 30 are driven by the force A applied from the rollers 29, 39 of the roller mounting bases 27, 37 in a direction orthogonal to the driven shafts 3, 6. A component force A2 is generated, and this component force A2 acts at right angles to the line connecting the axis of the driving or driven shafts 3 and 6 and the connection point of the speed change switching mechanism 48 to the link 41. As shown in FIG. 4, the axes of the driving or driven shafts 3 and 6 and the link 41
A cam rotational reaction force W is generated which is always perpendicular to the line connecting the connecting point to the cylindrical cam 2 and is opposite to the component force A2, and as shown in FIG.
4, 32 are supported
For the boss portions 13a, 19a of 9, the pulleys 10,
It acts to press the boss portions 13a, 19a at the center position of the range where the belt B of 16 is wound. In other words, this boss portion 13a,
The cam rotation reaction force W against the boss portion 19a is
a, 19a and the driving or driven shaft 3, 6 at the sliding part, the movable shaft 13, 1
9 receives thrust from the belt B, it acts so that a moment M2 is generated in the opposite direction to the moment M1 that acts in the direction of driving or tilting the movable shafts 13 and 19 with respect to the driven shafts 3 and 6. The moment M1 is canceled out and reduced, and as shown in FIG.
The surface pressure distribution on the inner periphery of the boss portions 13a, 19a with respect to the outer periphery of the driving or driven shafts 3, 6 is dispersed in the axial direction, and the large peak as in the conventional case (see Fig. 5b) is eliminated, and the pressure distribution on the inner periphery of the boss portions 13a, The sliding resistance of 19a becomes smaller. As this sliding resistance becomes smaller, the load that the belt-generated thrust F gives to the fixed points of the cylindrical cams 24 and 32, that is, the take-out thrust F' increases. 24 and 32 as extraction thrust F'.

The transmission device includes a driving pulley and a driven pulley 1.
The opening and closing forces between 0 and 16 are reversed, and both pulleys 10,
The cylindrical cams 24 and 32 of both cam mechanisms 22 and 30 are connected so that the opening and closing forces between the two cam mechanisms 22 and 30 partially cancel each other out, and the extraction thrust F1' or F2' of one cam mechanism 22 or 30 is transferred to the other. Since it is used for the belt thrust of the cam mechanism 30 or 22, when the gear ratio of the transmission is constant and no gear change is performed, the extracted thrust F1' is used as shown in FIGS. 6 and 7. , F2' in this embodiment (see Figure 7a) and in the conventional case (see Figure 7b)
Although it becomes larger than the above, the thrust extraction forces F1' and F2' are the same on the driving side and the driven side, and these cancel each other out, so that the thrust extraction efficiency is the same as in the conventional case. However, when changing the gear ratio, as shown in Fig. 8, the difference between the belt generated thrust F and the output thrust F1', F2' is the load (operating force) required for gear shifting operation, so in the conventional case (Figure 8b
), the remaining operating force increases as the extraction thrusts F1', F2' are smaller, whereas in this embodiment (see Figure 8a), the extraction thrusts F1', F2' are smaller.
Since 2' is large, the operating force can be reduced accordingly. As a result, cylindrical cam 2
The rollers 29, 39 of the roller mounting bases 27, 37 are in rolling cam contact with the cam surfaces 24a, 32a of the rollers 4, 32, and the driving or driven shafts 3, 6
The gear ratio can be changed smoothly even with a small operating force, and the gear ratio can be changed quickly even in an emergency.

In the above embodiment, the cylindrical cams 24, 32 (rotating cams) are mounted on the bearings 2 on the boss portions 13a, 19a of the movable shafts 13, 19 of the respective pulleys 3, 6.
3 and 31, but the present invention is not limited to this structure. For example, the cylindrical cams 24, 32
may be connected to the ends of the boss portions 13a, 19a.

Further, in the above embodiment, the rollers 29, 39 are brought into contact with the cam surfaces 24a, 32a of the cylindrical cams 24, 32, but the cam followers may be brought into direct contact with the cam surfaces.

Furthermore, in the above embodiment, the operation lever mounting member 34 is connected to the cylindrical cam 32 of the second cam mechanism 30 on the driven side.
However, it is also possible to attach it to the cylindrical cam 24 of the first cam mechanism 22 on the drive side and arrange the tip end 34a of the cam 24 to extend beyond the outer circumferential side of the drive pulley 10 to the side opposite to the first cam mechanism 22. Often, in that case the link 41 will be placed on the upper side in FIG.

It goes without saying that the present invention can also be applied to transmission devices for vehicles and other machines other than agricultural machines.

(Effects of the invention) As described above, according to the invention recited in claim (1), in a pulley type transmission equipped with a pair of variable pulleys, a transmission mechanism consisting of a cam mechanism that changes the pulley diameter of each variable pulley is interlocked. When the vibration systems of both variable pulleys are different due to the provision of a vibration-absorbing shock absorbing means consisting of a spring that limits the relative movement between these links and ball joints to the speed change switching mechanism consisting of links and ball joints. Even in the case of a variable pulley, the transmission of vibration between both variable pulleys can be suppressed by the spring, and the gear ratio can be maintained stably by eliminating the opening and closing of the pulley in a steady state, thereby suppressing early wear of the pulley sliding part. In addition, it is possible to prevent the belt from moving in the pulley radial direction, thereby suppressing excess heat generation and improving its durability. In particular, the straight rod-shaped links
The arrangement space for the speed change switching mechanism can be reduced and its layout can be facilitated, thereby making it possible to both facilitate the arrangement and layout of the speed change switching mechanism and suppress vibration transmission.

Further, according to the invention described in claim (2), the direction of the movable sheave of one variable pulley toward the fixed sheave and the direction of the movable sheave of the other variable pulley toward the fixed sheave are opposite to each other, and each variable pulley The movable shaft is rotatably and movably supported in the axial direction by a boss part on each rotating shaft, and one of the rotating cam or the fixed cam forms a cam surface, while the other forms a cam surface that rolls on the cam surface. Provide a roller that comes in contact with the
The rotary cam is supported on the outer periphery of the boss of the movable shaft via a bearing so that it can move integrally in the axial direction and can rotate relative to it, while the fixed cam is immovable in the axial direction but can rotate relative to the rotating shaft. This generates a cam rotational reaction force that acts on the outer periphery of the boss part of the movable sheave in the direction toward the axis of the rotating shaft through the bearing, and the moment generated by the thrust from the belt on the movable sheave is used to rotate the cam. The moment due to the reaction force offsets and reduces the
It is possible to suppress the peak of the surface pressure distribution in the axial direction of the boss part of the movable sheave and reduce the sliding resistance in the axial direction, increasing the extraction thrust that the belt generated thrust gives to the connection point to the cam. , it is possible to reduce the operating force as a difference between the thrust generated by the belt and the thrust to be taken out, and together with the cam contact between the rotary cam and the fixed cam via the rolling elements, the shift operating force is significantly reduced. can.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view of a transmission, and FIG. 2 is a sectional view thereof. Figure 3 is a schematic plan view showing the state of action of the cam rotation reaction force based on the relationship between the belt generated thrust and the force applied to the link, Figure 4 is a schematic front view of the same, and Figure 5 is a movable shaft due to the cam rotation reaction force. Fig. 6 is an explanatory diagram showing the relationship between the belt-generated thrust and the extraction thrust in both pulleys, and Fig. 7 shows the relation between the extraction thrust in both pulleys during non-shift operation. FIG. 8 is a diagram corresponding to FIG. 7 during a gear shift operation. 3... Drive shaft (rotating shaft), 6... Driven shaft (rotating shaft), 10... Drive pulley (variable pulley), 12...
... Fixed sieve, 13... Movable sieve, 15...
...belt groove, 16...driven pulley (variable pulley),
18...Fixed sieve, 19...Movable sieve,
21... Belt groove, 22, 30... Cam mechanism (speed change mechanism), 24, 32... Cylindrical cam (rotating cam),
24a, 32a...cam surface, 27, 37...roller mounting base (fixed cam), 40...ball joint, 41...link, 46...spring, 48...speed change mechanism, B...V belt .

Claims (1)

[Claims for Utility Model Registration] (1) A pair of rotating shafts arranged parallel to each other, a fixed shaft fixed to each rotating shaft so as to be rotationally integral and immovable in the axial direction; Rotatably and movably supported in the axial direction,
a pair of variable pulleys consisting of a movable sheave forming a belt groove with a V-shaped cross section between the fixed sheave; a transmission belt wound around between the belt grooves of both variable pulleys; It has a movable cylindrical rotary cam and a fixed cam that contacts the rotary cam, and a cam surface is formed on at least one of the rotary cam or the fixed cam, so that the rotary cam and the fixed cam can be rotated and fixed. A pair of transmission mechanisms that move the movable shafts of each of the variable pulleys in the axial direction to move toward and away from the fixed shaft by relative rotation of the cams, thereby changing the pulley diameter of the variable pulleys, and the rotation of one of the transmission mechanisms. It consists of a straight rod-shaped link connected to a rotating cam, and a ball joint connected to a rotating cam of the other transmission mechanism and slidably supported by the link, and the pulley diameters of both variable pulleys are mutually aligned. and a speed change mechanism that varies the speed ratio between the two rotary shafts by interlocking the two speed change mechanisms so as to change in opposite directions, and the speed change mechanism is configured to change the speed ratio between the ball joint and the link. What is claimed is: 1. A pulley type transmission comprising a spring arranged to limit relative movement between the two transmission mechanisms, and a buffer means for absorbing vibrations transmitted between the two transmission mechanisms. (2) The direction of the movable sheave of one variable pulley toward the fixed sheave and the direction of the movable sheave of the other variable pulley toward the fixed sheave are opposite to each other, and the movable sheave of each variable pulley has a boss on each rotating shaft. One of the rotary cam and the fixed cam has a cam surface formed thereon, while the other is provided with a roller that rolls into contact with the cam surface. The rotary cam is supported on the outer periphery of the boss part of the movable shaft via a bearing so that it can move integrally in the axial direction and can rotate relative to the rotary shaft, while the fixed cam cannot move in the axial direction and can rotate relative to the rotating shaft. The pulley type transmission device according to claim (1), characterized in that the pulley type transmission device is enabled.