JP3404184B2 - Pulley type transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulley type transmission, and more particularly, a belt is stretched over a pulley composed of a fixed sheave and a movable sheave respectively provided on a pair of rotating shafts, and an effective radius of each pulley. The present invention relates to the improvement of the link bar that links the movable sheaves to the one in which the gear ratio between both rotary shafts is changed by changing the.

[0002]

2. Description of the Related Art Conventionally, in agricultural machinery and the like, a pulley type transmission utilizing belt transmission has been widely used in order to shift the power of an engine and transmit it to a drive wheel or various working devices. As an example of a pulley type transmission utilizing this belt transmission, there is a conventional one such as, for example, Japanese Utility Model Laid-Open No. 57-16.
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 link bar via a rotating lever, when the movable sheave of one variable pulley approaches a fixed sheave facing it, the other The movable cams of the variable pulleys are rotated in cooperation with each other so that the movable sheaves of the variable pulleys move away from the fixed sheaves facing the variable pulleys, and the effective radius (pulley diameter) of each variable pulley with respect to the transmission belt is changed. A variable pulley type is known in which the gear ratio between the rotating shafts is changed. Further, an operation shaft is connected to the link bar, and the rotation cams are rotated in cooperation with each other by the movement of the link bar due to the operation of the operation shaft to obtain a desired gear ratio.

Further, as described above, since the direction of one movable sheave to the fixed sheave and the direction of the other movable sheave to the fixed sheave are set to be opposite to each other, the both rotary levers are The straight line connecting the connection points of the link bars to be connected is inclined with respect to the direction orthogonal to the rotation axis (the belt extension direction).

[0004]

By the way, in the conventional transmission as described above, no particular consideration is given to the connecting position of the operating shaft with respect to the link bar connecting the two rotating cams, and the shape of this link bar is not taken into consideration. Also, depending on the connecting position of the operating shaft, the component of the operating force acting on the link bar from the operating shaft may act in the torsion direction on the link bar. Specifically, for example, when the link bar is made of a triangular plate material in order to ensure the rigidity of the entire link bar, the turning lever is connected to two points of the three vertices and the remaining one point is connected. Although it is usually conceivable to connect the operating shaft, in this configuration, the operating force from the operating shaft is applied to the link bar because the distance between the connecting point of the operating shaft and the connecting point of the rotating lever in the link bar is large. On the other hand, there is a fear that the stress acts locally in the torsional direction due to the torsional action, which in some cases damages the link bar, making it impossible to perform the gear shifting operation. In view of this point, the inventors of the present invention have reached the present invention by considering setting the connecting position of the operation shaft to the link bar to an optimum position. The main object of the present invention is to improve the structure of the link bar, in particular, the connecting position of the operating shaft to the link bar, thereby avoiding local stress concentration on the link bar and improving its reliability. Especially.

[0005]

In order to achieve the above object, according to the present invention, the connecting position of the operating shaft with respect to the link bar is set in the vicinity of the connection point of the rotating lever in the link bar, so that the operating shaft is connected. The operation force applied from does not act in the direction of twisting the link bar.

Specifically, in the invention of claim 1, a pair of rotating shafts arranged in parallel to each other and the rotating shafts are respectively provided on the rotating shafts, and the rotating shafts are rotationally integrated with each other in the axial direction. A fixed sheave that is immovably fixed and supported, and a boss 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 that has a portion and is fitted and supported by the boss portion such that the movable sheave is rotatably integrated with the rotary shaft and is movable in the axial direction. One of the movable sheave faces the fixed sheave and the other movable sheave. The drive and driven pulleys, which are set in opposite directions to the fixed sheave, the belt wound between the belt grooves of the drive and driven pulleys, and the movable sheave rear side of the drive and driven pulleys, respectively. Arranged, each one another It is composed of a first cam and a second cam that come into cam contact, 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 with the movable sheave and relatively rotatable. 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 rotatable. A drive pulley that is an immovable fixed cam, and moves the movable sheave in the axial direction so as to move toward and away from the fixed sheave by relative rotation of the rotating cam and the fixed cam, thereby changing the effective radius of each pulley. Side and driven pulley side cam mechanisms, turning levers provided on the turning cams of both cam mechanisms, link bars connecting the turning levers to each other, and connecting to the link bars to the link bars. On the other hand, the rotation axis When the movable sheave of one of the drive and driven pulleys approaches the fixed stationary sheave of the drive and driven pulleys, the other movable sheave of the drive and driven pulley faces each other. Is arranged between the drive and driven pulleys and the gear shift switching mechanism that changes the gear ratio between the two rotating shafts by interlocking the two rotating cams so as to move away from the fixed sheave. It is premised on a pulley type transmission including a tension mechanism that presses a loose side span of a belt to be hung so that the belt bites into a belt groove of each pulley to generate a thrust force to the belt. Then, the link bar is made of a substantially triangular plate material, and each of the turning levers is connected to two points of the three vertex portions,
The connecting position of the operating portion with respect to the link bar is set at a position other than the remaining apex portion of the above-mentioned substantially triangular shape on the link bar and
The rotation lever is set at a position near the connection point .

With this structure, even when the operating portion for applying the operating force to the substantially triangular link bar is connected, the bending stress of the link bar is not concentrated by the operating force from the operating portion, and the link bar is broken. And the like can be reliably prevented.

According to a second aspect of the present invention, in the pulley type transmission according to the first aspect, the link bar is provided with pin holes for connecting the rotating levers at two vertex portions to which the rotating levers are connected. A bush made of sintered metal is fitted in the pin hole.

With this structure, wear of the connecting portion between each rotating lever and the link bar is reduced by the bush, so that stable shift operability can be obtained over a long period of time.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 3 show the entire configuration of a pulley type continuously variable transmission T according to an embodiment of the present invention. The transmission T is a power source between an engine and a drive wheel in a traveling agricultural machine (not shown). It is arranged in the transmission path.

1 and 4, reference numeral 1 denotes a case of the transmission T, which is divided into a front case 2 on the left side of FIG. 1 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. 1, and a boss-shaped (cylindrical) input bearing hole 2a is formed in the upper part in FIG. 1 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 member opened to the left side in FIG. 1, and a boss-shaped input bearing hole 3a in the upper part of FIG. 1 corresponds to the input bearing hole 2a of the front case 2, Further, similar output bearing holes 3b are formed in the lower portion so as to correspond to the output bearing holes 2b of the front case 2, respectively. 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 corresponding to the screw holes 4, 4, ... Bolt insertion hole 5,
5 are provided, and when assembling the front and rear cases 2 and 3, the flanges 2c and 3c are brought into contact with each other, and the assembly bolts 6 are inserted into the bolt insertion holes 5 of the rear case 3, respectively. The front end of the bolt 6 is screwed into the corresponding screw hole 4 of the front case 2 so that the cases 2 and 3 can be integrally assembled.

A plurality of screw holes 4 in the front case 2
4, screw holes 4 located near a tension pulley 41 (to be described later on the upper left side in FIG. 4), and screw holes 4 on the side substantially opposite to the tension pulley 41 with respect to the screw holes 4 (see FIG. Collars 7 and 7 are respectively inserted as knock pins in a pair with the one on the lower end of 4), and these 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. 4, the left and right intermediate portions of the lower portion 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.

The transmission case 1 includes an input shaft 9 (rotating shaft) and an output shaft 13 which are arranged in parallel with each other.
It is rotatably supported over 3. The input shaft 9 and the output shaft 13 rotate counterclockwise in FIG. The front end portion (the left end portion in FIG. 1) 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. 1) 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. 1) of the output shaft 13, and the output shaft 13 is inserted into the output bearing hole 2b of the front case 2 through the bearing 14 at the small diameter portion 13a. It is rotatably supported. On the other hand, the rear end of the output shaft 13 is rotatably supported in the output bearing hole 3b of the rear case 3 via a bearing 15.
The rear end projects outside the case 1 and is drivingly connected to driving wheels (not shown). A sleeve 16 (in this embodiment, the sleeve 16 and the output shaft 13 constitute a rotating shaft in the present invention) is fitted to the intermediate portion of the output shaft 13 so as to be relatively rotatable. The inner diameter of the front end portion of the sleeve 16 is made larger than that of the other portion to form a large diameter portion 16a. The large diameter portion 16a and the small diameter portion 13 at the front end of the output shaft 13 are formed.
A bearing 17 is provided between the bearing 14 and the rear portion 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.

A transmission pulley mechanism 20 for drivingly connecting the input shaft 9 and the output shaft 13 with a V-belt 30 in a variable speed manner 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
Is a flange-shaped fixed sheave 22 that is rotationally integrated and non-slidably keyed on the input shaft 9, and is slidable on the input shaft 9 by a boss portion 23a so as to face the fixed sheave 22. 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, there are a plurality of fins 22a, 22 for radially cooling the air which are radially arranged at equal intervals in the circumferential direction.
a, ... Are integrally formed.

On the other hand, a driven pulley 26, which is a speed change pulley having the same diameter as that of the drive pulley 21, is provided on the sleeve 16 which is externally fitted to the output shaft 13. The driven pulley 26 has a structure similar to that of the drive pulley 21, and includes a flange-shaped fixed sheave 27 key-joined to the sleeve 16 of the output shaft 13 so as to rotate integrally with the sleeve 16 and the sleeve 16 (output shaft). 13) is slidably and relatively rotatably coupled to the fixed sheave 27 by the boss portion 28a so as to face the fixed sheave 22 of the drive pulley 21 in the opposite direction to the facing direction of the movable sheave 23. It is composed of a flange-shaped movable sheave 28, and a belt groove 29 having a substantially V-shaped cross section is formed between these sheaves 27, 28. Fixed sheave 27 in this driven pulley 26
A plurality of fins 27a, 27a, ... Radially arranged radially at equal intervals in the circumferential direction are also integrally formed on the back surface of the fins, and the fins 22a of the respective fixed sheaves 22, 27 are formed. An air flow is generated in the case 1 by 27a to cool the heat generating portion.

The sliding structure of the movable sheave 23 of the drive pulley 21 with respect to the input shaft 9 and the sliding structure of the driven sheave 28 of the movable sheave 28 with respect to the sleeve 16 (output shaft 13) are the same. The driven pulley 26 will be described, and the same reference numerals are given to the drive pulley 21 side and detailed description thereof will be omitted. That is, as shown in FIG. 3, 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, on the outer peripheral surface of the sleeve 16 (the input shaft 9 on the drive pulley 21 side), at a position facing in the diametrical direction,
Notches 32, 32 formed by partially cutting a part of the outer peripheral surface of the sleeve 16 in the axial direction in parallel with the tangential direction by a predetermined depth.
Are formed. In addition, the sleeve 16 and the output shaft 13
A pin 33 penetrating both of them in the diametrical direction is fixedly supported on the (rotation shaft) by press-fitting to the sleeve 16 (press-fittingly 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. 3, the pin 33 has a long hole 36 having a longer 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 by the inner rings 34b on the protruding portions at both ends of the pin 33, and the bearings 34 are engaged with each other on the inner periphery of the boss portion 28a of the movable sheave 28. The outer ring 34 a is engaged with the groove 31 and comes into contact with the side surface of the engaging groove 31 to roll. 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.

Then, the belt groove 2 of the drive pulley 21.
4 and the belt groove 29 of the driven pulley 26 are wound around the V belt 30 such as a block belt, and the movable sheaves 23 and 2 of the pulleys 21 and 26 are wound around each other.
8 is brought into contact with and separated from the fixed sheaves 22 and 27, respectively, to change the belt winding diameter of the pulleys 21 and 26. For example, when the movable sheave 23 of the drive pulley 21 is brought close to 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 drive pulley 21 is made larger than that of the driven pulley 26. As a result, a high speed state in which the rotation of the input shaft 9 is increased and transmitted to the output shaft 13 is established. 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 is brought close to 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 transmitted to the output shaft 13 in a low speed state.

In the transmission case 1, the loose side span 30a of the pair of spans of the V belt 30 stretched between the drive 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. 5, 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 portion 43 extending in the direction from the tip end toward the base end side (substantially opposite to the tension shaft 40). The front end portion of is bent forward, and the bent portion has a spring locking portion 44 formed of a recess. On the other hand, as shown in FIGS. 4 and 7, on one inner surface of the front case 2, a ring-shaped tension collar 46 is attached and fixed 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. 44, and the tension arm 39 is urged to rotate counterclockwise in FIG. 4 by the spring force of the tension spring 48, and the inner surface of the loose side span 30a of the V belt 30 is attached to the tension pulley 41. 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 back side of the movable sheave 23 of the drive pulley 21 on the input shaft 9. ing. The cam mechanism 50 includes a rotating cam 51 having a cylindrical cam body 52 made of, for example, an aluminum alloy, and the rotating cam 51 is
On the boss portion 23a of the movable sheave 23, an outer fitting support is provided via 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, radially outward of the bearing 57 and circumferentially equiangularly spaced (180 ° apart).
10 to 12, the cam tips 53, 53 in the shape of an arc plate made of a pair of sintered metals are formed at the upper and lower positions.
However, the tapping screw 54 is inserted into the bolt insertion hole 53a formed in each cam tip 53 and screwed and fastened to the cam body 52 to be fixedly mounted. A surface 55 is formed. 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. 4; in FIG. 1, the output shaft 13 is shown for explanation).
(It is described so as to extend to the opposite side) and is provided so as to integrally rotate.

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 fixed cams, which come into cam contact with the cam surface 55 of the above, are arranged and fixed on the inner surface of the front case 2 along the radial direction of the input shaft 9. It is supported by the supporting shaft 60. That is, as shown in an enlarged manner in FIG. 6, a pair of bearing portions 61, 63 arranged in a line in the radial direction of the input shaft 9 are provided at a predetermined position on the inner surface of the front case 2, and the one bearing portion 61 is provided.
A bottomed screw hole 62 extending in a direction parallel to the input shaft 9, that is, in a direction from the inner surface of the front case 2 toward the opening is formed therein. Further, a concave portion 64 having a substantially semicircular cross section is formed at the tip of the other bearing portion 63. And the support shaft 60
Has a flat plate-shaped through-hole bolt hole 60a, and the other end of the support shaft 60 is tightly fitted in the recess 64 of the other bearing 63, and the mounting bolt 65 is By inserting the bolt hole 60a at one end of the support shaft 60 and screwing it into the screw hole 62 of the one bearing portion 61, the cam bearing 59 is fixedly supported by the support shaft 60 on the inner surface of the front case 2. ing.

On the other hand, on the output shaft 13, the driven pulley 26
On the back side of the movable sheave 28 in
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 structure as the drive pulley-side cam mechanism 50, and is mounted around the output shaft 13 via the bearing 74 on the bearing collar 68 fitted outside the boss portion 28a of the movable sheave 28. It has a rotating cam 69 which is relatively rotatable and axially movable and integrally fitted and supported. This rotating cam 6
Reference numeral 9 denotes a cam main body 70, and an end face opposite to the driven pulley 26, which is fixedly mounted 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 sintered metal having a pair 72, and each of the cam tips 71 is a rotating cam 51 of the drive pulley side cam mechanism 50.
(Note that the same as the rotation cam 51 shown in FIGS.
The tapping screw 54 is inserted into the bolt insertion hole 71a of the cam tip 71 and screwed and fastened to the cam body 70 to be fixed. Further, on the outer periphery of the cam body 70, it is downward along the line passing through the cam tips 71, 71, that is, the drive pulley side cam mechanism 50.
Rotating lever 73 extending in the same direction as the rotating lever 56 of
(In FIG. 1, it is illustrated so as to extend to the side opposite to the input shaft 9 for the sake of description), and is provided so as to integrally rotate.

On the back side of the rotating cam 69, a pair of cam receiving bearings 76, 76 as fixed cams that come into cam contact with the respective cam tips 71 are provided.
Are arranged in correspondence with the respective cam receiving bearings 76
Are supported on a support shaft 77 arranged and fixed on the inner surface of the rear case 3 along the radial direction of the output shaft 13. Since the support structure of the cam receiving bearing 76 is the same as that of the drive pulley side cam mechanism 50 (see FIG. 6), the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

2 and 8, the tip of the rotary lever 56 on the outer circumference of the cam 51 of the drive pulley side cam mechanism 50 and the rotary lever 73 on the outer circumference of the cam 69 of the driven pulley side cam mechanism 67. A link bar 79 is connected to the tip so as to rotate in association with each other. As shown in FIG. 9, the link bar 79 is made of a substantially elongated triangular plate material, and the middle portion thereof is bent upward so as not to interfere with the recessed portion (see FIG. 4) at the lower portion of the transmission case 1, and the front portion thereof is provided. A rib-shaped flange 79a is integrally formed on the edge. 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 a pin having a diameter smaller than that of the pin hole 80 is provided at the tip of the rotary lever 56 of the drive pulley side cam mechanism 50. A hole 81 is formed in parallel with the input shaft 9 so that both pin holes 80 and 81 are aligned with each other and a bush 82 made of a sintered metal is fitted into the pin hole 80 of the link bar 79. Pin hole 8
Link bar 7
9 and the tip of the rotary lever 56 are swingably connected by a link pin 83.

On the other hand, at the other end of the link bar 79, a pin hole 85 is formed also at the rear end (a part forming one of the remaining two apexes of the triangle), and the tip 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 so as to penetrate in parallel to the output shaft 13, respectively, so that both pin holes 85 and 86 are aligned with each other and the pin hole 8 of the link bar 79 is formed.
By inserting the link pin 88 into both pin holes 85 and 86 in a state where the sintered metal bush 87 is inserted into the pin 5, and preventing the link pin from coming off, the link bar 79 and the tip end portion of the rotating lever 73 are linked. Are connected so that they can swing. Then, the rotating levers 56, 73 and the link pins 83, 88
A gear shift switching mechanism 89 is configured by the link bar 79 and the link bar 79, and each cam mechanism 5 is configured by the gear shift switching mechanism 89.
The rotating cams 51, 69 of 0, 67 are rotated around the boss portions 23a, 28a of the movable sheaves 23, 28 in association with each other, and the cam surfaces 55, 7 of the respective cam tips 53, 71 are moved.
By rolling the cam receiving bearings 59 and 76 on the moving shaft 2, the movable sheaves 23 and 28 of the pulleys 21 and 26 are moved in the axial direction to be brought into contact with and separated from the fixed sheaves 22 and 27, respectively. The effective radii of the belt grooves 24 and 29, that is, the belt winding diameters of the pulleys 21 and 26 are made variable, and the pulley ratio between the pulleys 21 and 26, that is, the gear ratio of the transmission T is changed.

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. The 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, in the front wall portion of the front case 2, there is a boss-shaped shaft insertion hole 97 at a position substantially between the input shaft 9 and the output shaft 13 and on a plane passing through the shaft centers of both 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. 4, 2 and 8, the other end of the operating shaft 98 is located inside the transmission case 1, and the base end of the crank arm 100 is rotationally integrally welded and fixed to the other end. ing. The crank arm 100 is made of a plate material curved in a substantially V shape, and has a connecting rod 102 at its tip.
Are connected at one end. This connecting rod 102 is
A pair of link balls 101, 101, each of which has a shaft 101a rotatably supported at the front end thereof, are rotatably supported.
a and 101a are connected so as to be arranged in opposite directions. The connecting rod 10 is attached to the tip of the crank arm 100.
One of the two link balls 101 is connected by its shaft portion 101a. The other end of the connecting rod 102, that is, the shaft portion 101a of the other link ball 101 is connected to the link bar 79 in the vicinity of the rotation lever 56 of the drive pulley side cam mechanism 50. Then, the operating shaft 98 is rotationally switched between the Lo position and the Hi position by the operating lever, thereby actuating the speed change switching mechanism 89, and the rotating arms 56 protruding from the rotating cams 51 and 69. ，
By rotating 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 decelerating state or the accelerating state with respect to the input shaft 9 so as to shift gears. .

Reference numeral 107 is a dust seal arranged around the input shaft 9, the output shaft 13, and the operation shaft 98.

Next, the operation of the transmission according to the above embodiment will be described. Since the engine mounted on the agricultural machine is drivingly connected to the input shaft 9 of the transmission T and the output shaft 13 thereof is drivingly connected to the drive wheels, the rotational power of the engine is changed by the transmission T and then the drive wheels are changed. Be transmitted to. Since the rotating levers 56 and 73 of the drive and driven pulley side cam mechanisms 50 and 67 are linked by the link bar 79, the pulley ratio of the speed change pulley mechanism 20 is changed by the switching operation of the operation shaft 98, and the speed change is performed. The gear ratio of the machine 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 switched by the operation lever and is positioned at the Lo position. That is, the base end portion of the crank arm 100 is integrally fixed to the inner end of the operation shaft 98, and the tip end portion of the crank arm 100 is connected to the link bar 79 via the connecting rod 102. Since the rotation lever 56 on the outer circumference of the rotation cam 51 in the drive pulley side cam mechanism 50 and the rotation lever 73 on the outer circumference of the rotation cam 69 in the driven pulley side cam mechanism 67 are connected,
The crank arm 100 rotates in accordance with the rotation of the operation shaft 98, and the both rotation levers 56 and 73 rotate. Then, when the operation shaft 98 is switched to the Lo position, the rotary cam 69 of the driven pulley side cam mechanism 67 causes the cam tip 7 to move.
While rotating the cam receiving bearings 76, 76 on the cam surfaces 72, 72 of 1, 71, the driven pulley 26 rotates in one direction around the boss portion 28a of the movable sheave 28. By this rotation, the cam surfaces 72 are pushed by the cam receiving bearings 76, and the rotating cams 69 move on the sleeve 16 around the output shaft 13, so that the bearings 7 are attached to the cams 69.
The movable sheave 28, which is integrally movable, moves in the same direction via 4 to approach the fixed sheave 27. As a result, the driven pulley 26 is closed to increase the belt winding diameter, and the increase in the belt winding diameter causes the V belt 30 to move.
Attracted to the side.

At the same time, the L of the operating shaft 98 is
With the switching to the o position, the drive pulley side 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 one direction as the cam 69 of the driven pulley side cam mechanism 67. This cam 5
The rotation of 1 eliminates the pressing of the cam surface 55 of each cam tip 53 against the cam receiving bearing 59. Therefore, the tension of the belt 30 moving to the driven pulley 26 side causes the movable sheave 23 connected to the cam 51 and the bearing 57 to move on the input shaft 9 in a direction away from the fixed sheave 22. Both sheaves 22, 23
The drive pulley 21 is opened due to the separation of the above, 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 decelerated and transmitted to the output shaft 13. As a result, the transmission T is brought into the Lo state, and the rotation of the engine is decelerated 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 it is set to the position, in the switching state to this Hi position,
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, the movable sheave 23 in the drive pulley 21.
It rotates in the other direction around the boss portion 23a. As a result, the cam surface 55 is pushed by the cam receiving bearing 59, the cam 51 moves on the input shaft 9, and the movable sheave 23, which is 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.
The rotation of the cam 69 eliminates the pressure on the cam receiving bearing 76. Therefore, 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 bearing 74 via the cam 69.
8 moves on the sleeve 16 in a direction away from the fixed sheave 27, and the separation of the sheaves 27, 28 opens the driven pulley 26, and the belt winding diameter is reduced. As a result, the belt winding diameter of the drive pulley 21 becomes smaller than that of the driven pulley 26.
The rotation of the input shaft 9 is accelerated and transmitted to the output shaft 13. As a result, the transmission T is in the Hi state, and the rotation of the engine is accelerated and transmitted to the drive wheels.

In the case of this embodiment, the speed change pulley mechanism 20
The rotary cams 51, 69 of the cam mechanisms 50, 67 are supported on the bosses 23a, 28a of the movable sheaves 23, 28 of the pulleys 21, 26 of the above through the bearings 57, 74, respectively. , 69 Outer rotation lever 5
Since 6 and 73 are connected to each other by one link bar 79, when the speed change of the speed change pulley mechanism 20 is performed, the cam receiving bearings 59 and 76 respectively supported by the front case 2 and the rear case 3 move from the rotating cam 51. , 69, the force is applied to the cam surfaces 55 and 72 of the cam tips 53 and 71.
5, 72 acting in a direction perpendicular to the input shaft 9 and the output shaft 13, and a perpendicular component force of this force in the direction orthogonal to the input shaft 9 and the output shaft 13.
When operated at a right angle to the line connecting the shaft center of 3 and the connection point to the link bar 79, the pulley ratio of the line connecting the shaft center of the input shaft 9 and the output shaft 13 to the connection point to the link bar 79 Regardless of the change, a cam rotation reaction force that is a right angle and is opposite to the right angle component force is generated, and this cam rotation reaction force is applied to the boss portions 23a and 28a of the movable sheaves 23 and 28 on which the rotating cam is supported. , The pulleys 21 and 26 act so as to press the boss portions 23a and 28a at the center position of the area around which the belt 30 is wound. That is, the boss portions 23a, 28
The cam rotation reaction force with respect to a is a clearance in the sliding portion between the boss portions 23a and 28a and the input shaft 9 and the output shaft 13, and when the movable sheaves 23 and 28 receive thrust from the belt 30, the movable sheaves 23 and 28 are moved. Acts on the input shaft 9 and the output shaft 13 so as to generate a moment in the direction opposite to the moment acting in the tilting direction, and this moment cancels the original moment to make it smaller, and the boss portions of the movable sheaves 23, 28 become smaller. The surface pressure distributions of the inner circumferences of 23a and 28a with respect to the outer circumferences of the input shaft 9 and the output shaft 13 are dispersed in the axial direction, and the sliding resistance of the boss portions 23a and 28a is reduced. As the sliding resistance becomes smaller, the load of the belt-generated thrust applied to the fixed point by the rotating cams 51, 69 (that is, the take-out thrust) becomes larger. In other words, the belt-generated thrust does not have a large resistance and the rotating cam does not have a large resistance. It is transmitted to 51 and 69 as extraction thrust. When the pulley ratio is changed, the difference between the belt-generated thrust and the take-out thrust is the load (operating force) required for the gear shifting operation. Therefore, the amount of take-out thrust is large and conversely the operating force can be small. become. As a result, both of the speed change pulleys 2 in the speed change pulley mechanism 20.
The gear shift operation force can be reduced by the thrust balance of the belt 30 between the Nos. 1 and 26.

Next, the operation of assembling the tension spring 48 in the transmission case 1 while tensioning the tension spring 48 will be described with reference to FIG. 13. The speed change pulley mechanism 20, the tension mechanism 38, and the cam mechanisms 5 are previously attached to the front case 2.
0, 67, the speed change mechanism 89, the operating shaft 98, etc. are assembled to leave only the rear case 3 unassembled.
The spring mounting arm portion 43 of No. 9 and the tension collar 46 on the inner surface of the front case 2 are stretched 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.
3 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 in 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 tensioning spring 48 to the assembling jig 111, 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.

As described above, the link bar 79 is made of a substantially triangular plate material, and the rotary lever 56 of the rotary cam 51 of the drive pulley side cam mechanism 50 is provided at one end which is one of the three vertices. The rotating cam 69 of the driven pulley side cam mechanism 67 that is connected and is the rear side vertex of the remaining two vertices
Since the rotation lever 73 on the outer periphery is connected and the end of the connecting rod 102 on the operation shaft 98 side is connected to the rotation lever 56 side of the drive pulley side cam mechanism 50, the end of the connecting rod 102 is connected to the above. Compared with the case of connecting to the front vertex of the remaining two vertices, the bending stress is not concentrated on the link bar 79, and the breakage or the like can be reliably prevented.

Further, 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.

Although the present embodiment is applied to the transmission T having the speed change pulley mechanism 20 including a pair of speed change pulleys, the present invention has the fixed and movable sheaves facing each other on the rotary shaft. Any transmission having a transmission pulley can be applied.

In the present embodiment, the connecting rod 10 has a driving pulley on the upper side and a driven pulley on the lower side in FIG.
Although the connecting position of the second link bar 79 is set near the connection point of the rotary lever 56 on the drive pulley side, the present invention
However, the connection position of the connecting rod to the link bar may be set near the connection point of the rotation lever on the driven pulley side, with the driven pulley on the upper side and the driving pulley on the lower side.

[0048]

As described above, according to the first aspect of the present invention, the pair of rotary shafts are provided with the pulleys each having the fixed sheave and the movable sheave, and the belt is hung on each pulley and the cam mechanism is provided. The movable gear sheave is moved toward and away from the fixed sheave by the link mechanism, and the rotating cams of the cam mechanism are linked and linked by a link bar to make the gear ratio of the rotary shaft variable. Since the connecting position of the operating part for setting the link bar is set to a position near the connection point of one of the turning levers on the link bar, concentration of bending stress of the link bar due to the operating force from the operating part is eliminated. It is possible to reliably prevent the breakage and the like, and it is possible to prevent the breakage from causing an inoperable state of the gear shift operation, and it is possible to improve the reliability of the transmission.

According to the second aspect of the present invention, since the bush made of sintered metal is fitted in the pin hole for connecting the rotating levers formed in the link bar, the connecting between the rotating levers and the link bar. The wear of the parts can be reduced by the bush, and stable gear shifting operability can be obtained over a long period of time, so that the transmission can perform a highly reliable gear shifting operation over a long period of time. .

[Brief description of drawings]

FIG. 1 is a horizontal sectional view of a pulley type transmission according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a connecting structure of a link bar, a connecting rod, a crank arm, and an operating shaft of a speed change mechanism.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

FIG. 4 is a front view showing a pulley type transmission with a case opened.

FIG. 5 is an enlarged front view of a tension arm.

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

FIG. 7 is an enlarged cross-sectional view showing the structure of a spring mounting portion in the case.

FIG. 8 is an enlarged front view showing a connecting structure of a link bar, a connecting rod, a crank arm, and an operating shaft of the shift change mechanism.

FIG. 9 is a diagram showing a link bar.

FIG. 10 is an enlarged development view showing the mounting structure of the cam tip on the cam body.

FIG. 11 is an enlarged front view showing the mounting structure of the cam tip on the cam body.

FIG. 12 is an enlarged cross-sectional view showing the mounting structure of the cam tip on the cam body.

FIG. 13 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]

9 Input axis 13 Output shaft 21 Drive pulley 26 Driven pulley 22,27 fixed sheave 23, 28 movable sheaves 23a, 28a Boss part 24,29 Belt groove 30 V belt 50 Drive pulley side cam mechanism 51,69 Rotating cam 56, 73 Rotating lever 59,76 Cam bearing 67 Driven pulley side cam mechanism 79 Link bar 82,87 bush 98 Operation axis 100 crank arm 102 connecting rod

Front Page Continuation (72) Inventor Toshio Nakao 1-32 Chayamachi, Kita-ku, Osaka City, Osaka Prefecture Yanmar Agricultural Machinery Co., Ltd. (56) Reference JP-A-7-103309 (JP, A) 6249 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 9/00-9/26 F16H 59/00-61/12 F16H 61/16-61/36 F16H 63/00 -63/48

Claims (2)

(57) [Claims] 1. A pair of rotating shafts arranged in parallel to 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, A rotation lever provided on the rotation cams of the both cam mechanisms,
An operation of the operation unit includes a link bar that connects the respective rotation levers to each other, and an operation unit that is connected to the link bar and applies an operation force to the link bar in a direction orthogonal to the rotation axis. When the movable sheaves of the drive and driven pulleys approach the fixed sheaves facing each other due to the movement of the link bar, the two rotary cams are rotated in conjunction with each other so that the other movable sheaves move away from the facing fixed sheaves. A gear shift mechanism that changes the gear ratio between the two rotating shafts and a loose side span of a belt that is placed between the drive and driven pulleys and is wound between the pulleys so that the belt cuts into the belt groove of each pulley. In a pulley type transmission including a tension mechanism that presses against the belt to generate a thrust force to the belt, the link bar is a substantially triangular plate member, And the respective rotary lever two points are respectively connected, connecting position relative to the link bar operating part and the link bar other than the remaining top portion of said substantially triangular whereas
The pulley type transmission is characterized in that it is set at a position in the vicinity of a connection point with the rotation lever of the . 2. The pulley type transmission according to claim 1, wherein the link bar has pin holes for connecting a turning lever, which are formed at two apexes to which the turning lever is connected. Is a pulley type transmission in which a bush made of sintered metal is fitted.