JPH0914371A - Pulley type transmission - Google Patents

Abstract

PURPOSE: To provide stable operating physical force and a stable transmission gear ratio for a long period of time by increasing abrasion resistance and strength of a cam surface by providing a cam with a cam main body and a cam tip installed and fixed on this cam main body and consisting of an abrasion resistance material having the cam surface. CONSTITUTION: A cam main body 52 of a revolving cam 51 is externally fit and supported on a boss part of a movable sheave free to relatively rotate around an input shaft through a bearing and to move integrally in the axial direction. Additionally, a circular arc plate type cam tip 53 is fixed on the cam main body 52 by inserting a tapping screw 54 into a bolt insertion hole 53a on a facing end part to a cam receiver bearing 59. Thus cam tip 53 is made by applying carburization quenching treatment to ferrous sintered metal, and an inclined cam surface 55 inclined at a specified angle is formed on its surface. Consequently, the cam surface 55 on the revolving cam 51 is hardly abrased as the cam receiver bearing 59 is repeatedly rolled on it, and it is possible to stably maintain a transmission gear ratio for a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technique for a pulley type transmission.

[0002]

2. Description of the Related Art Conventionally, in agricultural machines and the like, a pulley-type transmission using a belt transmission has been frequently used in order to change the power of an engine and transmit the power to driving wheels or various working devices. As an example of a pulley type transmission using this belt transmission, a conventional pulley type transmission, for example,
As shown in Japanese Patent Laid-Open No. 4352, a fixed sheave fixed to each of a pair of rotating shafts arranged in parallel with each other is integrally and non-slidably fixed to each of the rotating shafts. A movable sheave, which is arranged so as to face the fixed sheave so as to form a belt groove having a substantially V-shaped cross section, and is rotatably integrated and slidably supported, and one of the movable sheaves faces the fixed sheave. And a pair of variable pulleys in which the direction of the other movable sheave toward the fixed sheave is set to be opposite to each other, and a transmission belt is wound between the belt grooves of these variable pulleys to move the variable pulleys. The movable sheave is fixed to the fixed sheave by the rotation of the rotation cam with respect to the fixed cam. To approach and separate By arranging a cam mechanism for moving, and connecting the rotating cams of both cam mechanisms with a rod and a speed change shaft, when the movable sheave of one variable pulley approaches the fixed sheave facing it, the other variable pulley moves. The rotating cams of the two cam mechanisms are rotated in cooperation with each other so that the sheave moves away from the fixed sheave facing the sheave, and the effective radius (pulley diameter) of each variable pulley with respect to the transmission belt is changed so that the rotating shafts A variable pulley type is known in which the gear ratio is changed.

By the way, when the movable sheave of the speed change pulley on the rotary shaft is moved in the axial direction by the cam on the back side thereof, aluminum or zinc is used as the cam because of its workability and weight reduction. A die-cast material of the system is used.

[0004]

However, a cam formed by die-casting a material such as aluminum as described above has a problem that the strength is lower than that of an iron-based material, particularly a hardened material thereof, and the wear resistance is poor. . Therefore, if the gear shifting operation is repeated many times, it is unavoidable that the cam surface of the cam is worn or deformed. At this time, the forward / backward position of the movable sheave with respect to the fixed sheave is changed from the initial state of use of the transmission. A change in the gear ratio causes a shift. In addition, if an indentation is made on the cam surface, it is possible to avoid that the cam contact is not made smoothly, the driving force of the cam for moving the movable sheave increases, and the gear shifting operation force increases compared to the initial use. Absent.

Although the entire cam may be molded by casting or the like, a quenching process is required after the molding, and since post-processing is required along with the quenching process, the cost is increased. There is a difficulty in doing so.

The present invention has been made in view of the above problems, and an object thereof is to improve the structure of the cam itself in the above-mentioned speed change pulley so that it does not require post-processing, is low in cost, and is resistant to wear of the cam surface. It is to increase the property and strength so that stable operation force and gear ratio can be obtained for a long period of time.

[0007]

In order to achieve the above object, in the present invention, only the cam surface portion of the cam is made of an abrasion resistant material which is separate from the other portions.

Specifically, in the invention of claim 1, a fixed sheave, which is rotatably integrated with the rotating shaft and is immovably supported in the axial direction, and a belt is wound around the fixed sheave. The transmission pulley is formed so as to face the fixed sheave so as to form a V-shaped belt groove, and includes a movable sheave that is supported on the rotating shaft by a boss portion so as to rotate integrally and movably in the axial direction. A first cam and a second cam arranged on the back side of the movable sheave and in cam contact with each other.
A cam, one of the first and second cams is supported on the boss portion of the movable sheave via a bearing so as to be movable integrally and relatively rotatably together with the movable sheave in the axial direction, and the other is axially supported by the rotary shaft. Is provided so as to be immovable and rotatable relative to the rotary shaft, one of the cams being a rotary cam rotatable about the rotary shaft, and the other being a non-rotatable fixed cam. A pulley type transmission equipped with a cam mechanism that moves the movable sheave in the axial direction so as to move toward and away from the fixed sheave by relative rotation between the rotating cam and the fixed cam to change the effective radius of the transmission pulley is premised. Is.

Each of the cams is provided with a cam body and a cam tip made of an abrasion-resistant material having a cam surface, which is fixedly attached to the cam body.

According to the second aspect of the present invention, a pair of rotary shafts arranged in parallel to each other and a pair of rotary shafts respectively provided on the rotary shafts are integrally fixed to the rotary shafts so as not to move axially and immovably. A fixed sheave, and a boss portion that is provided so as to face the fixed sheave so as to form a belt groove having a substantially V-shaped cross section between the fixed sheave and that extends in the axial direction on the back side. A movable sheave, which is externally fitted to and supported by the boss portion so as to rotate integrally with the rotary shaft and is movable in the axial direction, has one movable sheave facing toward the fixed sheave and the other movable sheave facing toward the fixed sheave. Drive and driven pulleys that are set in opposite directions, a belt wound between the belt grooves of these drive and driven pulleys, and a movable sheave rear surface side of the drive and driven pulleys, respectively. Cam contact A first cam and a second cam, and one of the first and second cams is supported on the boss of the movable sheave via a bearing so as to be movable integrally and relatively rotatable with the movable sheave in the axial direction, The other is provided on the rotary shaft so as to be immovable in the axial direction and rotatable relative to the rotary shaft, and one of the cams is a rotary cam rotatable about the rotary shaft, while the other is not rotatable. And a driving pulley side that moves the movable sheave in the axial direction so as to move toward and away from the fixed sheave by the relative rotation of the rotating cam and the fixed cam, and changes the effective radius of each pulley. When the driven pulley side cam mechanism and one movable sheave of the drive pulley and the driven pulley approach the fixed sheave facing each other, the rotating cams of both cam mechanisms are connected to each other so that the other movable sheave moves away from the facing fixed sheave. The looseness side span of the belt arranged between the drive and driven pulleys, which is arranged between the drive and driven pulleys, is connected to the gear shift mechanism that changes the gear ratio between the two rotating shafts by connecting and rotating the belt. Press so as to bite into the belt groove of each pulley,
It is premised on a pulley type transmission provided with a tension mechanism for generating thrust on a belt.

As in the first aspect of the invention, each of the cams is attached to and fixed to the cam body.
And a cam tip made of an abrasion resistant material having a cam surface.

According to the third aspect of the invention, in the cam mechanism, a cam tip having an inclined cam surface is attached to an end of one of the first and second cams facing the other cam, and the other cam is It is assumed that a rolling element that comes into contact with the inclined cam surface of the cam tip while rolling is provided.

In the invention of claim 4, the cam tip is made of sintered metal.

According to the fifth aspect of the present invention, the cam body is formed by die casting an aluminum alloy, and the cam tip is formed by quenching a ferrous sintered metal.

[0015]

With the above construction, according to the invention of claim 1, the rotary cam and the fixed cam of the cam mechanism rotate relative to each other during gear shifting of the transmission, and the relative rotation of the both cams causes the movable sheave of the shift pulley to rotate. And moves toward and away from the fixed sheave, which changes the effective radius of the pulley and changes the gear ratio.

At this time, each of the cams is provided with a cam body and a cam tip made of a wear-resistant material, which is fixedly mounted on the cam body. Since the cam tip is provided with the cam surface, the shifting operation is repeated. Also, it is possible to effectively prevent the cam surface of the cam tip from being worn or the cam surface being indented. Therefore, it is possible to suppress the change in the gear ratio and the increase in the gear shift operation force due to the wear of the cam, and to obtain the gear shift operability and the gear ratio stable over a long period of time.

Further, the cam portion of the cam may be separated as a cam tip, and only the cam tip may be processed for wear resistance, and the other cam bodies do not require post-processing as in the case of a cast cam. , There is no cost increase.

According to the second aspect of the present invention, when the gear ratio between the two rotary shafts is switched, one rotating cam (one of the first and second cams) of the drive pulley side or the driven pulley side cam mechanism is fixed to the fixed cam ( When it is rotated relative to the other of the first and second cams, the movable sheave of the pulley on the cam mechanism side moves in the axial direction to approach the fixed sheave, and the pulley closes. On the other hand, since the rotating cams of the drive and driven pulley side cam mechanisms are linked so as to interlock with each other by the shift changeover mechanism, the other rotating cam of the drive pulley side or the driven pulley side cam mechanism is also a fixed cam. Relative to the cam mechanism, the movable sheave of the pulley on the cam mechanism side moves axially away from the fixed sheave, and the pulley opens. In this way, the two pulleys move in the direction opposite to each other to move the movable sheave toward and away from the fixed sheave, and the speed ratio between the two rotating shafts is changed by the movement of the two movable sheaves in the reverse direction.

Then, the loose side span of the belt wound between the driving and driven pulleys is pressed by the tension mechanism, the belt bites into the belt groove of each pulley, and the wedge effect at that time generates belt thrust. Then, this belt thrust causes power to be transmitted between the rotating shafts.

In this way, the thrust force on the belt is generated by the pressing of the loose side span, and when the gear shift between the two rotary shafts is performed, the gear shift switching mechanism drives and the rotary cam in the driven pulley side cam mechanism interlocks, Since both pulleys open and close in synchronization with each other, the opening and closing behaviors of the drive and driven pulleys are reversed, the opening and closing thrusts between the two pulleys partially cancel each other, and the rest becomes the shift operation force. That is, in general,
The initial tension acting on the belt is divided into tension side and loose side tension by the rotational torque input to the drive pulley, and power is transmitted from the drive pulley to the driven pulley due to the difference between these tensions. The thrust (the force of the pulley pushing the belt) is substantially the same in a static state where the pulley does not rotate, or in a light load state where the transmission load is small even if the pulley rotates. On the other hand, when the transmission load increases, the thrust on the driving pulley side always becomes larger than the thrust on the driven pulley side due to a change in the tension distribution in the belt, and a difference occurs between the two thrusts. In the present invention, a cam mechanism is arranged on the back side of the movable sheave of each pulley, and these mechanisms move the movable sheave in the axial direction by relative rotation between the first cam and the second cam. The thrusts generated in the two pulleys are canceled each other, and a shift operation can be performed by applying an external force greater than the difference between the two thrusts. Therefore, the shifting operation force may be an operating force that exceeds the difference between the thrusts generated on the two pulleys, so that the shifting operation force can be greatly reduced even under a high load as well as a light load. it can.

Moreover, at that time, since the thrust generated in one pulley is transmitted to the other pulley as a thrust by the cam mechanism arranged on the rear side of the movable sheave of each pulley, the thrust of each pulley is It is possible to efficiently convert into torque for relatively rotating both cams of the pulley side cam mechanism, and the power transmission path between them can be shortened so that the sliding resistance becomes extremely small, and the gear shift operation force can be further reduced. .

At this time, a cam rotation reaction force is generated on both cams by the torque for relatively rotating the first and second cams, which is converted from the thrust of the pulley. Then, the cam rotation reaction force generated on one of the cams supported on the boss portion of the movable sheave via the bearing acts so as to press the boss portion of the movable sheave supporting the cam. In other words, the cam rotation reaction force against the boss is the moment acting in the direction of tilting the movable sheave with respect to the rotation shaft when the movable sheave receives thrust from the belt due to the clearance at the sliding portion between the boss and the rotation shaft. Acts in such a way as to generate a moment in the opposite direction, and the moment in the opposite direction causes the boss portion to maintain substantially parallelism with respect to the rotation axis, and the pressing force due to the cam rotation reaction force has a predetermined width. Acting on the boss portion via the bearing, the surface pressure distribution of the inner periphery of the movable sheave on the inner periphery of the boss portion with respect to the outer periphery of the rotating shaft is dispersed in the axial direction, and a large peak is eliminated. As a result, the sliding resistance of the boss portion is reduced. . The belt generated thrust is transmitted to the cam mechanism as a greater take-out thrust than in the related art because the sliding resistance is reduced.

Further, in the transmission, the rotating cams of both cam mechanisms are connected by a gear change mechanism so that the opening and closing forces between the two pulleys are reversed and the opening and closing forces between the two pulleys partially cancel each other out. Since the extraction thrust of one cam mechanism is used for the belt thrust of the other cam mechanism, if this relationship is compared to a seesaw, when the gear ratio is constant and gear shifting is not performed, Although the thrust itself is larger in the case of the present invention than in the conventional case, the extraction thrust is the same on the drive side and the driven side, and these are balanced with each other, and the thrust extraction efficiency is the same as in the conventional case.

However, when changing the gear ratio,
Since the difference between the belt-generated thrust and the take-out thrust is the load (operating force) required for the speed change operation, in the conventional case, the remaining man- agement force increases as the take-out thrust decreases, whereas in the present invention, Since the extraction thrust is large, the operation force is conversely small. As a result, the speed change between the two rotating shafts is promptly performed with a small operation force.

Also in the present invention, as in the case of the first aspect of the present invention, each of the cams is composed of a cam body and a cam tip made of a wear-resistant material that is fixedly attached to the cam body. Since the cam surface is provided, it is possible to prevent wear on the cam surface of the cam tip and indentation on the cam surface even if the gear shifting operation is repeated, which reduces costs and achieves stable gear shifting for a long period of time. Operability and gear ratio are obtained.

In the invention of claim 3, a cam tip having an inclined cam surface is attached to an end of one of the first and second cams of the cam mechanism facing the other cam, and the other cam has the inclination of the cam tip. Since the rolling element comes into contact with the cam surface while rolling, the rolling element rolls on the inclined cam surface of the cam tip when the movable sheave is moved in the axial direction by the operation of the cam mechanism. The sliding resistance between the cams at this time becomes the rolling resistance of the rolling elements, and the gear shift operation force can be reduced.

According to the invention of claim 4, since the cam tip is made of sintered metal, a cam tip having a desirable structure having wear resistance can be easily obtained.

According to the invention of claim 5, the cam body is die-cast from an aluminum alloy, so that the cost of the cam body can be reduced. Further, since the cam tip is obtained by quenching an iron-based sintered metal, the configuration of the sintered metal cam tip can be specifically obtained.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. 4 and 5 show the overall structure of a pulley type continuously variable transmission T according to an embodiment of the present invention. This transmission T is a power source between an engine and drive wheels in a traveling agricultural machine, which is not shown. It is arranged in the transmission path.

In FIGS. 4 and 5, reference numeral 1 denotes a case of the transmission T, which is divided into a front case 2 on the left side of FIG. 4 and a rear case 3 on the right side. The front case 2 is a dish-shaped one opened to the right side in FIG. 4, and in FIG. 4, a boss-shaped (cylindrical) input bearing hole 2a is formed in the upper part and an output of the same shape is formed in the lower part. The bearing hole 2b is recessed. Further, the rear case 3 is a dish-shaped one opened to the left side in FIG. 4, and a boss-shaped input bearing hole 3a in the upper part of FIG. 4 corresponds to the input bearing hole 2a of the front case 2, Similar output bearing holes 3b are formed in the lower portion so as to correspond to the output bearing holes 3b of the front case 2. A flange 2c is provided on the opening edge of the front case 2.
Is formed, and a plurality of screw holes 4, 4 are formed in the flange 2c.
4,... Are opened. On the other hand, a flange 3c joined to the flange 2c of the front case 2 is formed at the opening edge of the rear case 3, and a plurality of flanges 3c are formed on the flange 3c corresponding to the screw holes 4, 4,. Bolt insertion hole 5,
Are provided. When the front and rear cases 2 and 3 are assembled, the flanges 2c and 3c are brought into contact with each other to insert the assembly bolts 6 into the bolt insertion holes 5 of the rear case 3, respectively. The two cases 2 and 3 are integrally assembled by screwing the tip of the attached bolt 6 into the corresponding screw hole 4 of the front case 2.

The plurality of screw holes 4 in the front case 2
4, screw holes 4 located near a tension pulley 41 described later (the ones on the upper left side in FIG. 5), and screw holes 4 located substantially opposite to the tension pulley 41 with respect to the screw holes 4 (see FIG. Collars 7 and 7 are fitted and inserted as a knock pin in a pair with the one on the lower right side of 5). The collars 7 and 7 are adapted to perform centering when assembling the front and rear cases 2 and 3. There is.

As shown in FIG. 5, the lower left and right middle portions of the transmission case 1 are partially recessed so that the lower side of the transmission T does not interfere with the propeller shaft 113 extending in the longitudinal direction of the agricultural machine. There is.

In the transmission case 1, an input shaft 9 (rotary shaft) and an output shaft 13 arranged in parallel to each other are provided in front and rear cases 2,
3 is rotatably supported. The input shaft 9 and the output shaft 13 rotate counterclockwise in FIG. The front end portion (the left end portion in FIG. 4) of the input shaft 9 rotates in the input bearing hole 2a of the front case 2 via the bearing 10, and the rear end portion rotates in the input bearing hole 3a of the rear case 3 via the bearing 11. Supported as possible. The front end of the input shaft 9 (the left end in FIG. 4) projects from the case 1 to the outside, and the output shaft of the engine (not shown) is drive-connected to this end.

On the other hand, a small diameter portion 13a is formed at the front end portion (left end portion in FIG. 4) of the output shaft 13, and the small diameter portion 13a allows the output shaft 13 to pass through the bearing 14 in the output bearing hole 2b of the front case 2. It is rotatably supported. On the other hand, the rear end of the output shaft 13 is rotatably supported by an output bearing hole 3b of the rear case 3 via a bearing 15.
The rear end protrudes out of the case 1 and is drivingly connected to a driving wheel (not shown). A sleeve 16 (in this embodiment, the sleeve 16 and the output shaft 1 is provided at an intermediate portion of the output shaft 13).
3 and 3 constitute a rotating shaft in the present invention) are fitted to each other so as to be relatively rotatable. The inner diameter of the front end of the sleeve 16 is made larger than that of the other portions to form a large diameter portion 16a, and the large diameter portion 16a and the small diameter portion 13 at the front end of the output shaft 13 are formed.
The bearing 17 is interposed between the bearing 14 and the rear side of the bearing 14 by engaging the inner ring 17a with the small diameter portion 13a of the output shaft 13 and the outer ring 17b with the sleeve 16, respectively.

A transmission pulley mechanism 20 for drivingly connecting the input shaft 9 and the output shaft 13 by a V-belt 30 is accommodated in the transmission case 1. The speed change pulley mechanism 20 has a drive pulley 21 that is a speed change pulley arranged on the input shaft 9. This drive pulley 21
A flange-shaped fixed sheave 22 which is keyed integrally and non-slidably on the input shaft 9 in a non-slidable manner, and is slidable on the input shaft 9 by a boss 23a so as to face the fixed sheave 22 and It comprises a flange-shaped movable sheave 23 supported so as to be relatively rotatable, and a belt groove 24 having a substantially V-shaped cross section is formed between the sheaves 22 and 23. On the back surface of the fixed sheave 22, a plurality of fins 22a, 22 for air cooling are radially arranged at equal intervals in the circumferential direction.
are integrally formed.

On the other hand, a driven pulley 26 composed of a variable speed pulley having the same diameter as the driving pulley 21 is provided on the sleeve 16 externally fitted to the output shaft 13. The driven pulley 26 has the same configuration as that of the drive pulley 21, and includes a flange-shaped fixed sheave 27 which is keyed integrally and non-slidably on the sleeve 16 of the output shaft 13, and a sleeve 16 (output shaft). 13), the boss 28a is slidably and relatively rotatably coupled to the fixed sheave 27 so as to oppose the movable sheave 23 to the fixed sheave 22 in the driving pulley 21 in the opposite direction to the fixed sheave 22. A flange-shaped movable sheave 28 is formed, and a belt groove 29 having a substantially V-shaped cross section is formed between the sheaves 27 and 28. Fixed sheave 27 of the driven pulley 26
A plurality of fins 27a, 27a,... For cooling air that are radially arranged at equal intervals in the circumferential direction are integrally formed on the rear surface of the fixed sheaves 22, 27. An air flow is generated in the case 1 by the 27a to cool the heat generating portion.

The sliding structure of the driving pulley 21 with respect to the input shaft 9 of the movable sheave 23 and the sliding structure of the driven pulley 26 with respect to the sleeve 16 (output shaft 13) of the driven pulley 26 are the same. The driven pulley 26 will be described, and the same reference numerals will be given to the drive pulley 21 side, and detailed description will be omitted. That is, as shown in FIG. 7, on the inner peripheral surface of the boss portion 28a of the movable sheave 28 in the driven pulley 26, the fixed sheave 27 is moved from the end of the boss portion 28a on the fixed sheave 27 side to the diametrically opposed position. A pair of engagement grooves 31, 31 having a substantially rectangular cross-section extending in the axial direction over the entire end to the opposite side is formed by broaching.

On the other hand, the outer peripheral surface of the sleeve 16 (the input shaft 9 on the side of the drive pulley 21) is located at a position facing the diametrical direction.
Notches 32, 32 in which a part of the outer circumferential surface of the sleeve 16 in the axial direction is partially cut out by a predetermined depth in parallel with the tangential direction.
Are formed. Further, the sleeve 16 and the output shaft 13
On the (rotary shaft), pins 33 penetrating both in the diameter direction are fixedly supported by press-fitting into the sleeve 16 (press-fitted and fixed to the input shaft 9 on the drive pulley 21 side). It projects from the notch 32 by a predetermined dimension. As shown in FIG. 7, the pin 33 has a long hole 36 having a long diameter larger than the outer diameter of the pin 33 in the output shaft 13.
And is rotatable relative to the output shaft 13 by a predetermined angle. A pair of bearings 34, 34 are respectively supported on the projections at both ends of the pin 33 by respective inner races 34b. Each of the bearings 34 is engaged with the inner periphery of the boss 28a of the movable sheave 28. The outer ring 34 a is engaged with the groove 31 and rolls by contacting the side surface of the engagement groove 31. Further, the outer diameter of each bearing 34 (outer diameter of the outer ring 34a) is equal to that of the sleeve 16
The outer diameter of the (input shaft 9) is 1 / 2.5 or more.

The belt groove 2 of the driving pulley 21
The V-belt 30, which is, for example, a block belt, is wound between the belt pulley 4 and the belt groove 29 of the driven pulley 26, and the movable sheaves 23, 2 of the pulleys 21, 26 are wound around the V-belt 30.
8 is moved toward and away from the fixed sheaves 22 and 27, respectively, to change the belt winding diameter of each pulley 21 and 26. For example, when the movable sheave 23 of the driving pulley 21 approaches the fixed sheave 22 and the movable sheave 28 of the driven pulley 26 is separated from the fixed sheave 27, the belt winding diameter of the driving pulley 21 is made larger than that of the driven pulley 26. As a result, the rotation of the input shaft 9 is transmitted to the output shaft 13 at a high speed. On the other hand, conversely, when the movable sheave 23 of the drive pulley 21 is separated from the fixed sheave 22 and the movable sheave 28 of the driven pulley 26 approaches the fixed sheave 27, the belt winding diameter of the drive pulley 21 is reduced, By increasing the belt winding diameter of the driven pulley 26, the rotation of the input shaft 9 is decelerated and a low-speed state is transmitted to the output shaft 13.

In the transmission case 1, the loose side span 30a of the pair of spans of the V belt 30 stretched between the driving and driven pulleys 21 and 26 is pressed outward from the inner surface thereof. A tension mechanism 38 that generates a belt thrust by applying tension to the belt 30 is provided. As shown in FIG. 8, the tension mechanism 38 has a tension arm 39 rotatably fitted to and supported by a boss portion 39a on the base end side of a boss-shaped portion around the output bearing hole 2b in the front case 2. The boss portion 39a of the tension arm 39 is integrally welded to the main body of the tension arm 39. A tension shaft 40 extending rearward in parallel with the output shaft 13 (input shaft 9) is integrally welded to the tip end of the tension arm 39, and the tip end of the tension shaft 40 is a belt groove 24, 29 in each pulley 21, 26. A tension pulley 41, which is located at a portion and is capable of pressing the loose side span 30 a of the V belt 30 from the inner surface, is rotatably supported via a bearing 42. The position of the tension pulley 41 is always constant regardless of the axial movement of the V-belt 30 due to the gear shift.
1 is set at a position where it can contact a part of the inner surface of the belt 30 and press it. Both side surfaces of the tension pulley 41 in cross section have belt grooves 24 of the pulleys 21 and 26,
The angle is parallel to the side surface of the tension pulley 41, so that the inclination angle of the side surface of the tension pulley 41 matches the sectional angle of the belt grooves 24 and 29, and the axial length of the outer peripheral surface of the tension pulley 41 is smaller than the width on the outer surface side of the belt 30. Has also been made smaller.

The tension arm 39 is integrally formed with a spring mounting arm 43 extending in a direction from the distal end toward the proximal side (substantially opposite to the tension shaft 40). Is bent forward, and a spring engaging portion 44 formed of a concave portion is formed in the bent portion. On the other hand, as shown in FIGS. 5 and 9, a ring-shaped tension collar 46 is attached and fixed to one inner surface of the front case 2 by an attachment bolt 47 extending parallel to the output shaft 13 (input shaft 9). One end of a tension spring 48, which is a tension spring, is locked to the tension collar 46 in an externally fitted state, and the other end of the spring 48 is a spring locking portion of the spring mounting arm portion 43 of the tension arm 39. The tension arm 39 is urged in the counterclockwise direction in FIG. 5 by the spring force of the tension spring 48, and the tension pulley 41 causes the inner surface of the slack side span 30a of the V belt 30 to move. Press. Then, the rotational biasing force of the tension spring 48 with respect to the tension arm 39 is set so that the tension pulley 41 presses the loose side span 30a of the belt 30 with a tension larger than the maximum tension generated in the loose side span 30a. The belt thrust is generated by this tension.

A drive pulley side cam mechanism 50 as a drive mechanism for bringing the movable sheave 23 into and out of contact with the fixed sheave 22 is provided on the input shaft 9 on the rear side of the movable sheave 23 in the drive pulley 21. ing. The cam mechanism 50 includes a rotating cam 51 having a cylindrical cam body 52 made of, for example, an aluminum alloy die cast, and the cam body 52 of the rotating cam 51 is the boss portion 23 of the movable sheave 23.
It is externally fitted and supported on a by a bearing 57 so as to be relatively rotatable around the input shaft 9 and axially movable integrally.
On the end surface of the cam body 52 on the side opposite to the drive pulley 21 (the end portion facing the cam receiving bearings 59, 59 described later), the outer periphery of the bearing 57 in the radial direction and the circumferential direction at equal angular intervals (180 ° intervals). ) In the vertical position,
~ As shown in Fig. 3, a pair of arc-shaped cam tips 53,
The tapping screw 54 is attached and fixed by inserting the tapping screw 54 into a bolt insertion hole 53 a formed in each cam tip 53 and screwing and fastening it to the cam body 52. Each of the cam tips 53 is obtained by carburizing and quenching an iron-based sintered metal, and has an inclined cam surface 55 inclined at a predetermined angle on the surface thereof. Further, on the outer periphery of the cam body 52, a rotating lever 56 extending downward along a line passing through the cam tips 53, 53 (see FIG. 5 is shown in FIG. 4 so as to extend to the side opposite to the output shaft 13 for the sake of explanation). (Shown) are provided so as to integrally rotate.

Further, on the back side of the rotating cam 51, the cam tips 53 are provided at positions corresponding to the cam tips 53.
A pair of cam receiving bearings 59, 59 serving as rolling elements and a fixed cam that makes a cam contact with the cam surface 55 of the front case 2 are arranged.
It is supported by a support shaft 60 arranged and fixed on the inner surface of the input shaft 9 along the radial direction of the input shaft 9. That is, as shown in an enlarged manner in FIG. 6, a pair of bearings 61 and 63 arranged in a line in the radial direction of the input shaft 9 are provided at predetermined positions on the inner surface of the front case 2,
A bottomed screw hole 62 extending in a direction parallel to the input shaft 9, that is, a direction from the inner surface of the front case 2 toward the opening is formed in the one bearing portion 61. The other bearing 6
A concave portion 64 having a substantially semicircular cross section is formed at the tip of 3. Further, one end of the support shaft 60 is formed in a flat plate shape and a through-hole bolt hole 60a is formed, and the other end of the support shaft 60 is tightly fitted in the recess 64 of the other bearing 63. , The mounting bolt 65 to the bolt hole 6 at one end of the support shaft 60
The cam receiving bearing 59 is fixedly supported on the inner surface of the front case 2 by the support shaft 60 by inserting 0a and screwing it into the screw hole 62 of the one bearing portion 61.

On the other hand, on the output shaft 13, the driven pulley 26
At the back side of the movable sheave 28,
A driven-pulley-side cam mechanism 67 for bringing the stationary sheave 27 into and out of contact with the stationary sheave 27 is provided. The driven pulley-side cam mechanism 67 has the same configuration as that of the drive pulley-side cam mechanism 50, and is arranged around the output shaft 13 via a bearing 74 on a bearing collar 68 externally fitted to the boss portion 28a of the movable sheave 28. The rotary cam 69 has an externally fitted and supported rotatably rotatable and axially movable integral fit. This rotating cam 6
9 is a cam body 70 made of aluminum alloy die casting,
The end face opposite to the driven pulley 26 is mounted and fixed at a vertical position outside the bearing 74 in the radial direction of the output shaft 13 and at equal angular intervals in the circumferential direction.
Cam tips 71, 71 made of a pair of iron-based carburized and quenched sintered metal having two cam tips 71.
Is similar to the rotary cam 51 of the drive pulley side cam mechanism 50 (which will be described with reference to FIGS. 1 to 3 which is the same as the rotary cam 51), the tapping screw 54 is attached to the bolt insertion hole 71a of the cam tip 71. It is fixed by being threadedly fastened to the cam main body 70 by being inserted into. On the outer periphery of the cam body 70, a rotation lever 73 (FIG. 4) extending downward along a line passing through the cam tips 71, 71, that is, in the same direction as the rotation lever 56 of the drive pulley side cam mechanism 50. For the sake of explanation, it is described so as to extend on the side opposite to the input shaft 9) and is provided so as to integrally rotate.

On the back side of the rotating cam 69, there are fixed cams which make cam contact with the respective cam tips 71 in a rolling state and a pair of cam receiving bearings 76, 76 as rolling elements corresponding to the cam tips 71, 71. The cam receiving bearings 76 are arranged on the inner surface of the rear case 3 and the output shaft 13
Is supported on a support shaft 77 which is arranged and fixed along the radial direction. Since the supporting structure of the cam receiving bearing 76 is the same as that of the driving pulley side cam mechanism 50 (see FIG. 6), the same parts as those of FIG.

Then, as shown in FIG. 10 and FIG.
In the drive pulley side cam mechanism 50, the tip end of the turning lever 56 on the outer circumference of the cam 51 and the tip end of the turning lever 73 on the outer circumference of the cam 69 of the driven pulley side cam mechanism 67 are linked to each other so that they rotate. They are connected by 79. The link bar 79 is made of a substantially elongated triangular plate material, and an intermediate portion thereof is a recessed portion in the lower portion of the transmission case 1 (see FIG. 5).
The upper end is bent upward so as not to interfere with the front end, and a rib-shaped flange 79a is integrally formed on the front edge thereof.
A pin hole 80 is provided at one end of the link bar 79 (a portion forming one of the three apexes of the triangle), and the drive pulley side cam mechanism 5 is provided.
A pin hole 81 having a diameter smaller than that of the pin hole 80 is penetratingly formed in parallel with the input shaft 9 at the front end portion of the turning lever 56 of 0.
When the bush 82 made of sintered metal is fitted into the pin hole 80 of the link pin 83, the link pin 83 is inserted into both the pin holes 80 and 81 to prevent the link pin 83 from being pulled out.
The six tip portions are swingably connected by a link pin 83.

On the other hand, a pin hole 85 is formed also at the rear end portion of the other end portion of the link bar 79 (a portion forming one of the remaining two apexes of the triangle), and the tip end of the rotary lever 73 of the driven pulley side cam mechanism 67. The pin hole 8 having a smaller diameter than the pin hole 85
6 are formed in parallel with the output shaft 13 so that the pin holes 85 and 86 are aligned with each other and the pin holes 8 of the link bar 79 are formed.
By inserting the link pin 88 into the two pin holes 85 and 86 to prevent the link bar 88 from being pulled out while the sintered metal bush 87 is inserted into the bush 5, the link bar 79 and the tip of the rotating lever 73 are connected to the link pin 88. Are swingably connected to each other. Then, the rotating levers 56 and 73, the link pins 83 and 88
And a link bar 79, a speed changeover mechanism 89 is provided.
The rotating cams 51 and 69 at 0 and 67 are linked with each other to rotate around the bosses 23a and 28a of the movable sheaves 23 and 28, and the cam surfaces 55 and 7 of the respective cam tips 53 and 71.
By rolling the cam receiving bearings 59 and 76 on the movable sheave 2, the movable sheaves 23 and 28 of the respective pulleys 21 and 26 are moved in the axial direction so as to be opposed to and separated from the fixed sheaves 22 and 27, respectively. The effective radius of the belt grooves 24 and 29, that is, the belt winding diameter at each of the pulleys 21 and 26 is made variable to change the pulley ratio between the two pulleys 21 and 26, that is, the speed ratio of the transmission T.

On the driven pulley 26 side, a torque cam mechanism 91 for moving the movable sheave 28 in the axial direction to generate a belt thrust when a transmission torque acts to relatively rotate the movable sheave 28 and the output shaft 13. Is provided. This torque cam mechanism 91, as shown in FIG.
The boss portion 28a of the movable sheave 28 is inclined at a diametrically opposed position (a position offset by 90 ° from the engaging grooves 31, 31) toward the circumferential direction toward the axial direction of the output shaft 13. Moreover, a pair of cam holes 92, 92 penetrating the inner and outer surfaces of the boss portion 28a are provided. Further, the output shaft 1 is provided at a position diametrically opposed to the outer peripheral surface of the portion of the output shaft 13 not covered by the sleeve 16.
3. Notches 93, 93 are formed by cutting out a part of the outer peripheral surface in the axial direction partially in parallel to the tangential direction by a predetermined depth. A pin 94 penetrating in the diametrical direction is fixedly supported on the output shaft 13 by press fitting, and both ends of the pin 94 project from the notches 93, 93 by a predetermined dimension, and the projecting parts at both ends of the pin 94 respectively. , The movable sheave 2
8 is engaged with the cam hole 92 in the boss portion 28a of the outer ring 9
A bearing 95 for rolling the 5a in contact with the side surface of the cam hole 92 is supported. When a transmission torque acts on the driven pulley 26, the cam effect of the cam hole 92 and the bearing 95 causes the movable sheave 28 to move in the axial direction. It is moved to generate belt thrust.

Further, a boss-shaped shaft insertion hole 97 is formed in the front wall portion of the front case 2 at a position on the plane substantially between the input shaft 9 and the output shaft 13 and passing through the respective shaft centers of the shafts 9 and 13. An operation shaft 98 which is formed so as to penetrate therethrough and extends in a direction parallel to the input shaft 9 (output shaft 13) is rotatably supported by a bearing 99, and one end of the operation shaft 98 is outside the transmission case 1. It extends and has a quadrangular cross section, and an operation lever (not shown) is attached to the end of the unit so as to rotate integrally.

As shown in FIGS. 5, 10 and 11, the other end of the operating shaft 98 is located inside the transmission case 1, and the other end of the crank arm 100 is fixedly welded to the base end of the crank arm 100 so as to rotate together. ing. The crank arm 100 is made of a plate material bent in a substantially rectangular shape, and has a connecting rod 1
02 is connected to one end. This connecting rod 102
A pair of link balls 101, 101 each having a shaft portion 101a in the orthogonal direction rotatably supported at the distal end thereof.
01a and 101a are connected so as to be arranged in opposite directions, and one link ball 101 of the connecting rod 102 is attached to the tip of the crank arm 100 by its shaft 101a.
It is connected by. The other end of the connecting rod 102, that is, the shaft portion 101a of the other link ball 101 is connected to the vicinity of the rotating lever 56 of the driving pulley cam mechanism 50 by the link bar 79. And the operation axis 9
8 is switched between a Lo position and a Hi position by an operation lever to operate the transmission changeover mechanism 89,
Each rotating arm 5 projecting from each rotating cam 51, 69
By rotating the gears 6, 73 between the Lo and Hi positions and changing the pulley ratio of the speed change pulley mechanism 20, the output shaft 13 is switched to the deceleration state or the speed increase state with respect to the input shaft 9 to change the speed. ing. A dust seal 107 is arranged around the input shaft 9, the output shaft 13, and the operation shaft 98.

Next, the operation of the above embodiment will be described. The engine mounted on the agricultural machine is the input shaft 9 of the transmission T.
Since the output shaft 13 is drive-connected to the drive wheels, the rotational power of the engine is transmitted to the drive wheels after being speed-changed by the transmission T. Then, the rotating lever 5 in the drive and driven pulley side cam mechanisms 50 and 67.
Since 6 and 73 are linked by the link bar 79, the pulley ratio of the transmission pulley mechanism 20 is changed by the switching operation of the operation shaft 98, and the transmission ratio of the transmission T is switched.

(Low-speed state) Specifically, when the transmission gear ratio of the transmission T is lowered to the low-speed state (Lo state), the operating shaft 9
8 is rotated and operated by the operation lever to be positioned at the Lo position. That is, the base end of the crank arm 100 is integrally fixed to the inner end of the operation shaft 98, and the tip end of the crank arm 100 is connected to the link bar 79 via the connecting rod 102. Since the rotating lever 56 on the outer periphery of the rotating cam 51 in the driving pulley side cam mechanism 50 and the rotating lever 73 on the outer periphery of the rotating cam 69 in the driven pulley side cam mechanism 67 are connected,
With the rotation of the operation shaft 98, the crank arm 100 rotates, and the two rotation levers 56, 73 rotate. When the operating shaft 98 is switched to the Lo position, the rotating cam 69 of the driven pulley side cam mechanism 67 moves its cam tip 7
The driven pulley 26 rotates in one direction around the boss 28a of the movable sheave 28 while rolling the cam receiving bearings 76 on the cam surfaces 72, 72 of the base 71. By this rotation, the cam surfaces 72 are pushed by the cam receiving bearings 76, and the rotating cam 69 moves on the sleeve 16 around the output shaft 13, and the cam 69
The movable sheave 28 which moves integrally with the movable sheave 28 moves in the same direction and approaches the fixed sheave 27 via the movable sheave 4. As a result, the driven pulley 26 closes and the belt winding diameter increases, and the V-belt 30 is driven by the driven pulley 26
Attracted to the side.

At the same time, L of the operating shaft 98 is
o, the driving pulley cam mechanism 50 is synchronized with the movement of the movable sheave 28 of the driven pulley 26.
The rotating cam 51 rotates on the input shaft 9 in the same direction as the cam 69 of the driven pulley side cam mechanism 67. This cam 5
Due to the rotation of 1, the pressing of the cam surface 55 of each cam tip 53 against the cam receiving bearing 59 is eliminated. Therefore, the cam 51 and the movable sheave 23 connected thereto via the bearing 57 move on the input shaft 9 in a direction away from the fixed sheave 22 by the tension of the belt 30 moving to the driven pulley 26 side. Both sheaves 22, 23
, The drive pulley 21 is opened and the belt winding diameter is reduced. As a result, the belt winding diameter of the driven pulley 26 becomes larger than that of the drive pulley 21, and the rotation of the input shaft 9 is reduced and transmitted to the output shaft 13. As a result, the transmission T enters the Lo state, and the rotation of the engine is reduced and transmitted to the drive wheels.

The tension arm 39 is moved by the urging force of the tension spring 48 of the tension mechanism 38 as shown in FIG.
Is urged to rotate in a clockwise direction by the tension pulley 41 at its tip end to press the inner surface of the loose side span 30a of the belt 30, and the pressing force imparts tension to the belt 30.
At this time, this tension is larger than the maximum tension generated in the slack side span 30a, so that the belt tension causes a wedge effect on the pulleys 21 and 26 of the belt 30 to generate thrust, and this thrust causes both pulleys 21 and 26 to be generated. Power is transmitted via the belt 30 between them.

(High speed state) On the other hand, the operating shaft 98 is set to Hi.
When the position is switched to the Hi position,
The movable sheave 23 of the drive pulley 21 while the cam 51 of the drive pulley side cam mechanism 50 rolls the cam receiving bearing 59 on the cam surface 55 of each cam tip 53.
About the boss 23a in the other direction. As a result, the cam surface 55 is pushed by the cam receiving bearing 59 so that the cam 51 moves on the input shaft 9, and the movable sheave 23 integral with the cam 51 moves in the same direction to move the fixed sheave 22.
Approach. As a result, the drive pulley 21 is closed to increase the belt winding diameter, and the V belt 30 is pulled toward the drive pulley 21 side due to the increase in the belt winding diameter.

At the same time, the cam 69 of the driven pulley side cam mechanism 67 rotates on the sleeve 16 in the same other direction as the cam 51 of the drive pulley side cam mechanism 50.
Due to the rotation of the cam 69, there is no pressing against the cam receiving bearing 76. For this reason, due to the tension of the belt 30 moving to the drive pulley 21 side, the movable sheave 2 connected to the cam 69 and the cam 69 via the bearing 74.
8 moves on the sleeve 16 in a direction away from the fixed sheave 27, and the separation between the sheaves 27 and 28 opens the driven pulley 26 to reduce the belt winding diameter. As a result, the belt winding diameter of the driving pulley 21 is
And the rotation of the input shaft 9 is accelerated and transmitted to the output shaft 13. As a result, the transmission T enters the Hi state, and the rotation of the engine is accelerated and transmitted to the drive wheels.

In the case of this embodiment, the rotary cams 51, 69 of the cam mechanisms 50, 67 are mounted on the bearings 57, 69 on the boss portions 23a, 28a of the movable sheaves 23, 28 of the pulleys 21, 26 of the speed change pulley mechanism 20, respectively. The rotation lever 5 on the outer circumference of both the rotation cams 51 and 69 is supported via 74.
6 and 73 are connected by one link bar 79, so that when the speed change of the speed change pulley mechanism 20 is switched, the rotating cam 51 is moved from the cam receiving bearings 59 and 76 supported by the front case 2 and the rear case 3, respectively. , 69 apply force to the cam surfaces 55, 72 of the cam tips 53, 71.
5 and 72, and a force perpendicular to the input shaft 9 and the output shaft 13 is applied to the input shaft 9 and the output shaft 1.
When acting at right angles to the line connecting the axis of No. 3 and the connection point to the link bar 79, the pulley ratio of the pulley ratio to the line connecting the axis of the input shaft 9 and the output shaft 13 and the connection point to the link bar 79. Regardless of the change, a cam rotation reaction force is generated at a right angle and opposite to the right angle component, and this cam rotation reaction force is applied to the boss portions 23a, 28a of the movable sheaves 23, 28 on which the rotating cams are supported. The pulleys 21 and 26 act to press the bosses 23a and 28a at the center of the area around which the belt 30 is wound. That is, the bosses 23a, 28
The cam rotation reaction force with respect to a is a clearance in a sliding portion between the bosses 23a and 28a and the input shaft 9 and the output shaft 13, and is defined by the movable sheaves 23 and 28 when the movable sheaves 23 and 28 receive thrust from the belt 30. Acts in a direction opposite to the direction acting in the direction of tilting the shaft with respect to the input shaft 9 and the output shaft 13, and this moment cancels out the original moment and reduces the moment. The surface pressure distribution on the inner periphery of the input shaft 9 and the outer periphery of the output shaft 13 on the inner periphery of the shafts 23a and 28a is dispersed in the axial direction, and the sliding resistance of the bosses 23a and 28a is reduced. As the sliding resistance decreases, the load of the belt-generated thrust applied to the fixed point by the rotating cams 51 and 69 (that is, the take-out thrust) increases. 51 and 69 are transmitted as the extraction thrust. When changing the pulley ratio, the difference between the belt generated thrust and the take-out thrust is the load (operating force) required for the speed change operation. Therefore, the larger the take-out thrust, the smaller the operation force is. become. As a result, the two speed change pulleys 2 in the speed change pulley mechanism 20 are used.
The shift operation force can be reduced by the thrust balance of the belt 30 between 1 and 26.

Moreover, the pair of cam tips 53, 71 having the inclined cam surfaces 55, 72 are attached to the cam bodies 52, 70 of the rotating cams 51, 69 in the cam mechanisms 50, 67, respectively, and the cases 2, 3 Each cam tip 5 on the inner surface
Since the cam receiving bearings 59 and 76 that come into contact with the inclined cam surfaces 55 and 72 of the rollers 3 and 71 while rolling are supported, the operation of the cam mechanisms 50 and 67 causes the pulleys 21 and 2 to move.
The sliding resistance when moving the movable sheaves 23 and 28 of No. 6 in the axial direction becomes the rolling resistance of the cam receiving bearings 59 and 76, and the gear shift operation force can be further reduced.

Further, in this embodiment, the movable sheave 23 of the drive pulley 21 moves on the input shaft 9 at the time of shifting as described above.
Further, when the movable sheave 28 of the driven pulley 26 receives the transmission load torque on the sleeve 16 and moves in the axial direction, the bearings 34 on the pins 33 projecting from the outer periphery of the input shaft 9 or the sleeve 16 are changed. Movable sheaves 23, 2
The bosses 23a and 28a of FIG. The sliding resistance at this time is the rolling resistance between the outer peripheral surface of the outer ring 34a of the bearing 34 and the side surface of the engagement groove 31 and the rolling resistance of the inner and outer rings of the bearing 34, and no sliding resistance occurs. Therefore, the shift operation force can be further reduced by the sliding resistance composed of the rolling resistance.

Further, since the outer diameter of the bearing 34 is 1 / 2.5 or more of the outer diameter of the input shaft 9 or the sleeve 16, which is a relatively large diameter, the Hertz stress generated in the engaging groove 31 and the bearing 34 is small. The outer ring 34 of the bearing 34 becomes smaller
a It is not necessary to quench the outer peripheral surface and the side surface of the engaging groove 31,
Cost can be reduced.

Further, one pin 33 is diametrically penetrated through the input shaft 9 or the sleeve 16 so that both ends thereof are projected onto the surface of the input shaft 9 or the sleeve 16, and the projected pin 33 is formed.
Since the bearings 34, 34 are respectively supported on both ends of the bearing, the pins 33 for supporting the bearings 34, 34 can be commonly used to reduce the number of parts and facilitate assembly.

Further, the engaging groove 31 on the inner periphery of the boss portions 23a, 28a of each of the movable sheaves 23, 28 has the boss portion 23.
Since the a and 28a are broached in the lengthwise direction, the sheave portions of the movable sheaves 23 and 28 are obstructed as compared with the case where the engaging groove 31 is punched from the outer peripheral side of the boss portions 23a and 28a. Without engaging the engaging groove 31 with the bosses 23a, 2
8a can be machined over the entire length, and the bearing 3
4 is effectively moved, and the boss 2
The total length of 3a and 28a can be shortened, and movable sheaves 23 and 28
As a result, the pulleys 21 and 26 can be made compact.

Further, the rotating cams 51, 69 in the cam mechanisms 50, 67 are cam bodies 52, 70 and cam tips made of hardened iron-based sintered metal attached to the cam bodies 52, 70. 53, 71, that is, only the portion of the rotating cams 51, 69 in contact with the cam receiving bearings 59, 76 is separated from the other portions, and the hard sintered metal cam tip 5 different from that is formed.
3 and 71, the cam surfaces 55 and 72 of the rotating cams 51 and 69 have the cam receiving bearings 59 and
Almost no wear occurs due to the repeated rolling of 76, and the gear ratio and the gear shifting operation force of the transmission T can be stably maintained from the initial stage of use for a long period of time.

Incidentally, Table 1 is a test conducted by the present inventor. The output torque of the transmission T is 15 N-m, the input rotation speed is 2736 rpm, the gear ratio in the Lo state is 0.6, and the gear ratio in the Hi state is The gear ratio is 1.66, from the initial use Lo state to Hi
The operation force to the state is 6 N-m, and the operation force from the Hi state to the Lo state is 5 N-mw. Then, after maintaining the Lo state for 3 seconds, shifting from the Lo state to the Hi state takes 3 seconds, then holding the Hi state for 3 seconds, and then shifting from the Hi state to the original Lo state taking 3 seconds. Total 1
The operation for 2 seconds was set as one cycle, and the deformation amount of the cam portion, the change amount of the gear ratio, and the change amount of the operating force after 30,000 cycles were evaluated.

According to Table 1, it can be seen that the example of the present invention is smaller in the amount of deformation of the cam portion and has no change in the gear ratio and the operating force even when the gear shifting is repeated, as compared with the comparative example and the conventional example. .

[0066]

[Table 1]

By forming the cam surfaces 55 and 72 of the cams 51 and 69 on the cam tips 53 and 71 which are separate from the cam bodies 52 and 70 in this manner, the cam tips 51 and
It suffices to perform wear-resistant processing (quenching processing) only on 69, and the cam bodies 52 and 70 do not have to be post-processed as in the case where the entire cam is made of cast metal, and cost reduction can be achieved. . Further, the cam tips 53 and 71 can be easily replaced with other ones, and the specification of the inclination of the cam surfaces 55 and 72 can be easily changed.

Moreover, the cam tips 53, 71 of the rotating cams 51, 69 have a radius larger than the positions of the bearings 57, 74 for supporting the cam bodies 52, 70 on the boss portions 23a, 28a of the movable sheaves 23, 28. Since it is arranged on the outside in the direction, the cam surfaces 55 of the cam tips 53 and 71,
72 can be arranged closer to the center side of the pulleys 21 and 26 (to the fixed sheaves 22 and 27 side) than the bearings 57 and 74. Accordingly, the lengths of the cam mechanisms 50 and 67 in the axial direction can be shortened to make the pulleys 21 and 26 compact.

Further, since the torque cam mechanism 91 is provided on the driven pulley 26 side, when a transmission torque acts on the driven pulley 26 and the movable sheave 28 and the output shaft 13 rotate relative to each other, the boss of the movable sheave 28 is rotated. The side surface of each inclined cam hole 92 of the portion 28 a is the bearing 9 on the outer circumference of the sleeve 16.
5, the movable sheave 28 is axially moved by the cam effect, and a belt thrust is generated.

At this time, the pair of bearings 95, 95 of the torque cam mechanism 91 are supported by both ends of the pin 94 press-fitted and fixed to the output shaft 13 at a portion not covered by the sleeve 16, while the movable sheave is being moved. The pin 33 for supporting the bearing 34, which slidably engages the sleeve 28 with the sleeve 16, is inserted into an elongated hole 36 having a longer diameter larger than the outer diameter of the pin 33 in the output shaft 13 so as to form a predetermined angle with the output shaft 13. Since it is capable of relative rotation, the output shaft 13
The engagement of the torque cam mechanism 91 with the movable sheave 28 and the engagement of the sleeve 16 with the movable sheave 28 are separated. Therefore, the pulley 26 including the torque cam mechanism 91
Even in this case, the sliding structure of the movable sheave 28 can utilize the bearing 34.

The small diameter portion 13a at the front end of the output shaft 13 is also used.
The sleeve 16 on the outer ring 17b of the bearing 17 arranged in
Of the small diameter portion 13 of the output shaft 13 to the inner ring 17a.
Since the step portion between a and the other portion is locked, the inner ring 17a of the bearing 17 shares the thrust load by the torque cam mechanism 91, and the outer ring 17b shares the thrust load acting on the fixed sheave 27 from the belt 30. Thus, the resistance of the relative rotation of the sleeve 16 and the output shaft 13 can be made a small rolling resistance between the inner and outer races 17a and 17b of the bearing 17. The sleeve 16
A needle bearing (not shown) may be interposed between the inner peripheral surface and the outer peripheral surface of the output shaft 13, or the needle bearing and the bearing 17 may be provided in combination.

Further, in the tension mechanism 38,
Since the tension arm 39, its boss portion 39a, the tension shaft 40, and the spring attachment arm portion 43 are all joined and integrated by welding, the structure of the tension mechanism 38 is simplified, the number of parts is reduced, and the assemblability is improved. Can be improved.

Further, since the fixed side end of the tension spring 48 is locked to the tension collar 46 mounted and fixed in the transmission case 1, the spring 48 can be locked and fixed to the case 1 side. It ’s easy and
Since the spring 48 does not go out of the transmission case 1, the degree of sealing of the transmission case 1 can be enhanced.

Here, the work of assembling the tension spring 48 in the transmission case 1 while tensioning the tension spring 48 will be described with reference to FIG. 12. In the front case 2, the speed change pulley mechanism 20, the tension mechanism 38, the cam mechanisms 50, 67, the gear changeover mechanism 89, the operation shaft 98, etc. are assembled so that only the rear case 3 is not assembled, and the tension spring 48 is the spring mounting arm portion 43 of the tension arm 39 and the collar for tensioning the inner surface of the front case 2. It hangs with 46 in a contracted state. At this time, since the tension spring 48 is contracting, the tension pulley 41 causes the tension-side span 3 of the belt 30 to relax.
0a is largely pressed and transmission case 1 (front case 2)
It will be in a state of being spilled out.

The shaft engaging portion 111a is provided on one side of the tip portion.
However, the collar engaging portion 111 is provided on the other side of the predetermined position of the intermediate portion.
Plate-shaped assembling jig 111 in which b is notched
, The rear case 3 to the front case 2, both flanges 2c,
3c is tentatively attached in a close state, the shaft engaging portion 111a of the assembly jig 111 is engaged with the tension shaft 40, and the assembly jig 111 is pushed in this state to extend the tension spring 48. Tension pulley 41
The inside of the transmission case 1 and then the assembly jig 1
11 as a fulcrum at an engagement position with the tension shaft 40.
2 in the counterclockwise direction to turn the collar engaging portion 111b,
The collar 7 fitted into the screw hole 4 of the flange 2c of the front case 2 near the tension pulley 41 is engaged and stopped. In this state, the tension spring 48 is expanded and the tension pulley 41 moves into the transmission case 1, and the tension pulley 41 is positioned at the position of the normal gear shift state in which the inner surface of the belt 30 is pressed. Thereafter, the case 3 after the temporary attachment is assembled to the front case 2 by inserting and fastening the assembly bolts 6, 6, ... And the assembly jig 111 is rotated clockwise just before the assembly is completed. Then, after removing from the gap between the front and rear cases 2 and 3, the assembling of the front and rear cases 2 and 3 may be completed.

At this time, since the collars 7, 7 as knock pins are fitted into the pair of screw holes 4, 4 of the front case 2 in advance, when the rear case 3 is positioned and assembled to the front case 2, Both the above collars 7 and 7 are attached to the rear case 3
It is possible to perform accurate positioning simply by fitting and inserting into the corresponding bolt insertion holes 5 and 5, and the positioning can be performed easily.

Moreover, one of the collars 7 and 7 also serves as an engaging portion for fixing the assembling jig 111 to the tension spring 48 in the extended state, so that this engaging portion and the positioning collar Also, the number of parts can be reduced and the assembling work of the case 1 (the assembling work of the transmission T) can be facilitated.

The link bar 79 is made of a substantially triangular plate material, and one end of one of the three vertices of the link bar 79 is provided at one end of the rotary lever 7 of the rotary cam 51 of the drive pulley side cam mechanism 50.
3 is connected, the rotation lever 73 on the outer periphery of the rotation cam 69 of the driven pulley side cam mechanism 67 is connected, and the connecting rod 1 on the operation shaft 98 side
Since the end of 02 is connected to the drive pulley side cam mechanism 50 near the turning lever 56, compared to the case where the end of the connecting rod 102 is connected to the front apex of the remaining two apexes. Since there is no concentration of bending stress on the link bar 79, it is possible to reliably prevent breakage and the like.

Further, the bushes 8 made of sintered metal are respectively provided in the pin holes 80 and 85 at both ends of the link bar 79.
2, 87 are fitted and inserted, and with the bushes 82, 87 fitted, the link pins 83, 88 are inserted into the pin holes 80, 85 and the pin holes 81, 86 at the tips of the rotating levers 56, 73. Since the rotating levers 56, 73 and the link bar 79 are swingably connected, wear of these connecting portions is reduced by the bushes 82, 87, and stable shift operability is ensured over a long period of time. Obtainable.

The cam bearings 59 and 76 of the cam mechanisms 50 and 67 are supported on support shafts 60 and 77 mounted on the inner surface of the transmission case 1, and one end of each of the support shafts 60 and 77 is used for shifting. Bearing part 6 on the inner surface of machine case 1
3 is fitted in the concave portion 64, and the other end is screwed and fastened to the other bearing portion 61 by the mounting bolt 65. Therefore, the mounting bolt 65 is fixedly attached to the case 1 only by bolting the other end portion. The cam bearings 59 and 76 can be supported on the inner surface of the transmission case 1 in a cantilevered manner.
It can be easily attached and supported by.

The screw holes 62 into which the mounting bolts 65 for fastening the end portions of the support shafts 60 and 77 are screwed are formed in the transmission case 1 in a direction parallel to the input / output shafts 9 and 13. Since it extends in the direction from the inner surface toward the opening, if the hole portion for the screw hole 62 is formed when casting the transmission case 1, it can be easily formed only by processing the screw portion thereafter. The screw hole 62, the input / output shaft 9,
A hole for inserting a tool and a lid portion after the machining are not required when forming in a direction orthogonal to 13.

In the above embodiment, the cam tips 53, 7 are
Although an iron-based sintered alloy is used as 1, a pressed material or the like can also be used.

Further, the above-mentioned embodiment is applied to the transmission T having the speed change pulley mechanism 20 composed of a pair of speed change pulleys. However, in the present invention, the fixed and movable sheaves are arranged to face each other on the rotary shaft. Any transmission having a transmission pulley can be applied.

[0084]

As described above, according to the first aspect of the present invention, the rotary sheave is provided with the fixed sheave and the movable sheave which is arranged to face the movable sheave so as to come in contact with and separate from the sheave, and the movable sheave is provided with the cam mechanism. In the pulley type transmission adapted to be moved in the axial direction by a cam, the cam is composed of a cam body and a cam tip made of a wear resistant material which is provided separately from the cam body. Further, in the invention of claim 2, drive and driven pulleys respectively provided on a pair of rotating shafts arranged in parallel with each other, a belt wound between these pulleys, and a movable sheave rear surface of each pulley. A cam mechanism that is disposed on the side and that moves the movable sheave in the axial direction by the relative rotation of the rotating cam with the fixed cam, and when one of the variable sheaves of both variable pulleys approaches the fixed sheave, the movable sheave of the other pulley is moved. Of the belt that is wound between both variable pulleys and the gear change mechanism that changes the gear ratio between both rotary shafts by rotating the rotating cams of both cam mechanisms so that they move away from the fixed sheave. In a variable pulley type transmission including a tension mechanism that presses the slack side span so that the belt bites into the belt groove of each pulley to generate thrust on the belt, A cam body the arm, fixedly attached to the cam body was composed of a Kamuchippu consisting wear-resistant material. Therefore, according to these inventions, it is possible to suppress the change in the gear ratio and the increase in the gear change operation force due to the wear of the cam due to the repetition of the gear change operation, and while reducing the cost, the gear change operability and the gear change of the transmission for a long period of time can be achieved. The ratio can be improved and maintained.

According to the third aspect of the present invention, the cam tip is provided on one of the cams of the cam mechanism which come into cam contact with each other.
By providing the other cam with a rolling element that comes into contact with the inclined cam surface of the cam tip, it is possible to reduce the shift operation force by using the sliding resistance between the cams as rolling resistance.

According to the fourth aspect of the present invention, since the cam tip is made of sintered metal, a cam tip having a desirable structure having abrasion resistance can be easily obtained.

According to the fifth aspect of the present invention, the cam body is made of a die-cast molding material of aluminum alloy and the cam tip is made of a ferrous sintered metal that is quenched. Can be realized.

[Brief description of the drawings]

FIG. 1 is an enlarged development view showing a mounting structure of a cam tip on a cam body.

FIG. 2 is an enlarged front view showing the mounting structure of the cam tip on the cam body.

FIG. 3 is an enlarged plan view showing a mounting structure of a cam tip on a cam body.

FIG. 4 is a horizontal sectional view of a pulley type transmission according to an embodiment of the present invention.

FIG. 5 is a front view showing the pulley type transmission with a case opened.

FIG. 6 is an enlarged sectional view showing a structure of a cam receiving bearing mounting portion in a case.

7 is an enlarged sectional view taken along line VII-VII of FIG.

FIG. 8 is an enlarged front view of a tension arm.

FIG. 9 is an enlarged cross-sectional view showing a structure of a spring mounting portion in the case.

FIG. 10 is an enlarged front view showing the connecting structure of the link bar, the connecting rod, the crank arm, and the operating shaft of the speed change mechanism.

FIG. 11 is an enlarged plan view showing a connecting structure of the link bar, the connecting rod, the crank arm, and the operating shaft of the speed change mechanism.

FIG. 12 is a front view showing a state in which front and rear cases are assembled while tension springs are tensioned by a jig.

[Explanation of symbols]

 T transmission 1 transmission case 2 front case 3 rear case 4 screw hole 7 collar 9 input shaft 13 output shaft 16 sleeve 17 bearing 20 speed change pulley mechanism 21 drive pulley 26 driven pulley 22, 27 fixed sheave 23, 28 movable sheave 23a, 28a Boss part 24, 29 Belt groove 30 V belt 31 Engagement groove 33 Pin 34 Bearing 38 Tension mechanism 39 Tension arm 41 Tension pulley 48 Tension spring 50 Drive pulley side cam mechanism 67 Driven pulley side cam mechanism 51, 69 Rotating cam 52 , 70 Cam body 53, 71 Cam tip 55, 72 Inclined cam surface 56, 73 Rotating lever 57, 74 Bearing 59, 76 Cam receiving bearing 60, 77 Support shaft 61, 63 Bearing portion 62 Screw hole 64 Recessed portion 65 Mounting bolt 70 C Main body 79 Link bar 80,85 Pin hole 82,87 Bushing 83,88 Link pin 89 Speed change mechanism 91 Torque cam mechanism 98 Operation shaft 102 Connecting rod 111 Assembly jig

Claims (5)

[Claims] 1. A belt groove having a substantially V-shaped cross section, around which a belt is wound, is formed between a fixed sheave that is rotatably integrated with a rotary shaft and is immovably supported in the axial direction, and the fixed sheave. The movable sheave is arranged so as to face the fixed sheave and is supported by the rotating shaft so as to rotate integrally with the boss portion and to be movable in the axial direction, and is provided on the back side of the movable sheave. , A first cam and a second cam that are in cam contact with each other, and one of the first and second cams is axially movable together with the movable sheave via a bearing on the boss portion of the movable sheave, and is rotatable relative to the movable sheave. Is supported on the rotary shaft, the other is provided on the rotary shaft immovably in the axial direction and is rotatable relative to the rotary shaft, and one of the cams is a rotary cam rotatable around the rotary shaft, while the other Is immovable A pulley provided with a cam mechanism that is a cam and that moves the movable sheave in the axial direction so as to move toward and away from the fixed sheave by relative rotation between the rotating cam and the fixed cam, thereby changing the effective radius of the shift pulley. A pulley type transmission, wherein each of the cams comprises a cam body and a cam tip which is fixedly mounted on the cam body and is made of an abrasion resistant material having a cam surface. 2. A pair of rotating shafts arranged in parallel with each other, and fixed sheaves provided on the rotating shafts, respectively, which are fixed to the rotating shafts so as to rotate integrally and immovably in the axial direction. Provided so as to face the fixed sheave so as to form a belt groove having a substantially V-shaped cross section between the fixed sheave and the fixed sheave,
And a movable sheave that has a boss portion that extends in the axial direction on the back side and that is externally fitted and supported by the boss portion so as to rotate integrally with the rotating shaft and be movable in the axial direction. To the drive sheave and the driven sheave to the fixed sheave of the other movable sheave, and a belt wound between the belt grooves of the drive sheave and the driven sheave. A first cam and a second cam, which are respectively arranged on the back side of the movable sheaves of the pulley and are in cam contact with each other.
A cam, one of the first and second cams is supported on the boss portion of the movable sheave via a bearing so as to be movable integrally and relatively rotatably together with the movable sheave in the axial direction, and the other is axially supported by the rotary shaft. Is provided so as to be immovable and rotatable relative to the rotary shaft, one of the cams being a rotary cam rotatable about the rotary shaft, and the other being a non-rotatable fixed cam. A drive pulley side and a driven pulley side cam mechanism for changing the effective radius of each pulley by moving the movable sheave in the axial direction so as to move toward and away from the fixed sheave by relative rotation between the rotating cam and the fixed cam, When the movable sheaves of one of the drive and driven pulleys approach the fixed sheaves facing each other, the rotary cams of the two cam mechanisms are interlocked with each other to rotate so that the other movable sheave moves away from the fixed sheaves facing each other. The speed change mechanism that changes the speed ratio between the two rotating shafts, and the loose side span of the belt that is placed between the drive and driven pulleys and is wound between both pulleys. In a pulley type transmission having a tension mechanism that presses so as to bite into the belt to generate a thrust force to the belt, each of the cams has a cam body and is fixedly mounted on the cam body, and has a cam surface and is provided with wear resistance. A pulley type transmission comprising a cam tip made of a conductive material. A pulley type transmission characterized in that 3. The pulley type transmission according to claim 1 or 2, wherein the cam mechanism is provided with a cam tip having an inclined cam surface at an end portion of one of the first and second cams facing the other cam body. On the other hand, the other cam includes a rolling element that comes into contact with the inclined cam surface of the cam tip while rolling, and a pulley type transmission. 4. The pulley type transmission according to claim 1, 2 or 3, wherein the cam tip is made of sintered metal. 5. The pulley type transmission according to claim 4, wherein the cam body is die cast from an aluminum alloy, and the cam tip is a hardened ferrous sintered metal. And pulley type transmission.