JP2001277888A - Traveling transmission for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of holding friction by correct energization force of a speed changing lever, and easily adjusting the energization force. SOLUTION: This device is provided with a continuously variable transmission, a speed changing pedal, and the speed changing lever 26 for setting- changing an operation position of the speed changing pedal, a holding mechanism 60 for bolding the operation position by the speed changing lever 26 by friction is composed of friction plates 41, 42 to hold friction, a pressing mechanism 61 to press the friction plates 41, 42 in a pressing direction, and an energization means 62 to provide pressure to the pressing mechanism 61 in such a direction as to press the friction plates 41, 42, and the pressing mechanism 61 to the friction plates 41, 42 is composed to provide pressure by lever action of a rotary lever 70 operated to rotate around a fixed support point P0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural work vehicle such as a tractor, a lawn mower, a combine machine, a rice transplanter, a transport vehicle, and a construction having a continuously variable transmission of a hydrostatic type or a belt type for traveling. The present invention relates to a traveling transmission for a working vehicle such as a vehicle.

[0002]

2. Description of the Related Art In a work vehicle of this kind, for example, when a mower is mounted on an agricultural tractor to perform lawn mowing work, a continuously variable transmission is provided so that the lawn mowing work can be performed while traveling at a constant speed. And a so-called cruise control mechanism configured to include a holding mechanism capable of holding the gear at a desired shift position, and a shift lever for operating the holding mechanism. With this configuration, the holding mechanism is operated in accordance with the operation of the shift lever, and the continuously variable transmission can be held at a desired shift position by the holding mechanism.
This allows the vehicle to run at a constant speed without continuously depressing the speed change pedal, which is useful in reducing the operator's work load.

Conventionally, as a traveling transmission for a working vehicle having such a cruise control mechanism, for example, as shown in FIG. 20 of Japanese Patent Application Laid-Open No. Friction members are provided on both sides of the pivot portion of the operable shift lever, and the friction member is urged toward the side where the friction force is increased by a coil spring, so that an arbitrary operation position of the shift lever is held by the friction force. Such a configuration is known.

[0004]

In the above-mentioned conventional structure, the coil spring for pressing and fixing the friction member to fix the position is used to reliably restrict the return of the speed change lever during the traveling operation and perform the constant speed traveling. Used. However, if the biasing force of the coil spring is set high to obtain a sufficient frictional force, it is effective to reliably control the return of the shift lever and maintain the constant speed running state. It is heavy, and it is inconvenient that it is difficult to perform the speed change operation smoothly. Conversely, if it is set too weak, the purpose of setting and holding the speed change lever at the intended constant speed position cannot be fulfilled. For this reason, it is difficult to perform some operations, so be patient and secure sufficient frictional force, or set the frictional force to the minimum value required to maintain constant speed and shift lightly to the allowable limit. There is a choice of whether to make adjustments so that the operation can be performed. However, in reality, in the conventional structure in which the effective length of the coil spring is directly adjusted by tightening bolts and nuts, the nut tightening amount is small. Significant changes are likely to occur in the operation, and the adjustment operation requires considerable skill. Also, even after starting the constant speed running after frictionally fixing the operation position of the shift lever, when the brake pedal is depressed during stopping or turning of the aircraft, if the shift lever is still set to the constant speed traveling state, the body braking is performed. Therefore, it is necessary to release the constant speed traveling with the depression of the brake pedal. At this time, if a coil spring for urging the friction member that has a strong urging force with priority given to frictional stop of the shift lever is adopted, the brake release by operating the brake pedal is performed by the coil. Since the release operation must be performed against the strong spring pressure of the spring, the release operation itself is heavy, and there is a problem that the operation is also difficult in this respect.

[0005] One object of the present invention is to provide a traveling transmission for a working vehicle equipped with a continuously variable transmission for traveling, wherein the operation of a transmission lever can be performed lightly.
An object of the present invention is to provide a traveling transmission for a working vehicle having a structure capable of holding friction with an appropriate urging force and easily adjusting the urging force. Another object of the present invention is to make it possible to release the holding of the shift lever accompanying the brake operation by a light operation. Still another object is to make it possible to set the speed of the shift lever with a light operation.

[0006]

Means for solving the problems The technical means of the traveling transmission for a working vehicle according to the present invention taken to achieve the above object are as follows.

[Invention according to claim 1] A continuously variable transmission for traveling, a shift pedal for shifting the continuously variable transmission, a shift lever for changing the operation position of the shift pedal, and a shift for the shift And a holding mechanism for holding an operation position by a lever by friction, wherein the continuously variable transmission and the speed change pedal are linked via a first link mechanism, and the stepless transmission is operated to shift the continuously variable transmission. And a second link mechanism for mechanically linking the shift lever with the holding mechanism and the shift pedal. The shift mechanism is operated to operate the holding mechanism and the second shift mechanism.
In a traveling transmission for a working vehicle, wherein the shift pedal can be operated and held at a desired shift position via a linkage mechanism, the holding mechanism comprises a friction plate for holding friction, and the friction plate being pressed against the friction plate. A pressing mechanism for pressing the friction plate against the friction plate, and a pressing mechanism for applying a pressing force to the side of pressing the friction plate against the pressing mechanism. It is configured to apply a pressing force by a lever action of a rotating lever that is operated to rotate by.

According to the first aspect of the present invention, by operating the shift lever, the shift pedal can be operated and held at a desired shift position via the holding mechanism and the second linkage mechanism. In addition, the continuously variable transmission can be operated and held at a desired shift position via the first linkage mechanism. In this holding mechanism, when the friction plate is pressed and urged, the friction plate is not directly pressed by the urging means but is urged by a lever action of a turning lever which is turned around a fixed fulcrum. Therefore, the urging force of the urging means can be reduced by the amount that the boosting action by the lever can be used. In addition, when such a rotating lever is used, when adjusting the urging force of the urging means, the rotating lever is present even before the adjusting action of the urging means reaches the friction plate. I have. Therefore, by utilizing the difference in the swing amount of the rotating lever, the operation amount can be reduced and transmitted, contrary to the boost, and the adjustment operation itself can be easily performed.

According to a second aspect of the present invention, as described in the second aspect, a release mechanism for operating the rotating lever of the pressing mechanism to a side that releases or reduces the pressing force on the friction plate by the urging means. It is preferable that the release mechanism is linked to the braking operation of the brake operating tool so as to perform the release operation.

The provision of such a release mechanism is synergistic with the fact that the urging force itself by the urging means is small, as described above, so that the release operation force when the brake operating tool is operated when the machine is stopped or the like. Can be reduced.

According to a third aspect of the present invention, the distance from the fixed fulcrum, which is the center of rotation of the rotating lever, to the position where the rotating lever presses the friction plate side. The distance may be set so as to be smaller than the distance to the release operation position on the rotating lever by the release mechanism.

With this configuration, the urging force itself by the urging means can be reduced, and the releasing operation can be performed more lightly by effectively utilizing the boosting effect by the lever ratio of the rotating lever. Can be.

According to a fourth aspect of the present invention, in configuring the pressing mechanism for pressing the friction plate toward the press-contact side, a rotating lever that is rotated around a fixed fulcrum, Composed with a pressing body that transmits the rotating motion of the rotating lever as a pressing action against the friction plate,
In addition, the notch for link formed on the shaft of the pressing body along the pressing direction is changed to the shaft center of the locking pin on the side of the rotation lever which is engaged with the notch for link. It is good to form so that it may be engaged at a position deviated to the lateral side closer to the rotation fulcrum than the axis of the part.

When the pressing mechanism is configured as described above, the distance from the rotation fulcrum to the locking pin is shortened for the entire length of the rotation lever, and the lever ratio of the rotation lever as the pressing mechanism is minimized. Can be used effectively. That is, for example, an engaging hole for inserting a locking pin is formed on the center axis of the shaft portion of the pressing body,
As compared with the case where the locking pin of the rotating lever is inserted into the engagement hole, the engaging portion can be set to a position deviated to one lateral side off the center of the shaft portion of the pressing body, so that the pressing body of the pressing body is The engagement point can be brought closer to the pivot point without being affected by the thickness of the shaft.

According to a fifth aspect of the present invention, in configuring the pressing mechanism for pressing the friction plate toward the pressure contact side, the pressing mechanism for pressing the friction plate toward the pressure contact side is fixed. A pivoting lever pivotally operated around a fulcrum and a pressing body for transmitting the pivoting movement of the pivoting lever as a pressing action against the friction plate, wherein the pivotal support portion of the pivoting lever is And a pivot notch provided in the fixing portion to be engaged with the fulcrum pin, and the pivot notch is provided with the locking pin of the rotating lever. And may be formed at a position offset from the fixing portion toward the locking pin.

By using the notch for pivotal support constructed as described above, it is not necessary to make the rotating lever a complete shaft and boss fitting structure. Therefore, even under the condition that the rotation fulcrum shafts have the same shaft diameter, it is possible to further shorten the interval with the locking pin by the notch that can be formed smaller in size than using such a boss portion. Become.

According to a sixth aspect of the present invention, there is provided a release mechanism for operating the rotary lever on a side for releasing or reducing the pressing force on the friction plate by the urging means. A first rotating member that is rotated around a first rotation axis at a fixed position in conjunction with a braking operation of a brake operating tool, and around a second rotation axis in a direction intersecting the first rotation axis; A second rotating member that is operated to rotate,
The rotation of the rotation member may be transmitted to the second rotation member by rotation, and the rotation of the second rotation member may cause the rotation lever to swing toward the urging force release side.

As described above, the operation of the brake operating tool is performed by the first operation.
By transmitting the rotation of the rotating member and the second rotating member to the rotating lever through two-stage rotational movement, the influence of the discrepancy in the moving direction between the transmitting direction of the operating force of the brake operating tool and the operating direction of the rotating lever is reduced. With smooth rotation, the operating force can be transmitted even more lightly.

According to a seventh aspect of the present invention, the speed change lever is configured to be swingable in a direction different from the speed change operation direction, and the swing operation in the different direction is rotated. A release operating portion for transmitting as an operating force to the biasing force release side of the moving lever is provided on the shift lever, and the shift lever is moved in the shift operation direction while maintaining the swing operation state in the different direction. It is good to be able to operate.

With this configuration, the influence of the urging force of the urging means can be reduced not only when the above-described brake operating tool is operated but also when the shift operation lever is operated.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Overall Structure] FIG. 1 shows an agricultural tractor as an example of a working vehicle, in which a pair of left and right front wheels 1, an engine 4 and a clutch 6 are arranged at the front of the body. A pair of right and left rear wheels 2 and a transmission case 9 are arranged at the rear of the vehicle, and the clutch 6 and the transmission case 9 are connected to each other via right and left body frames 3 each having a vertical wall shape. A ceiling plate (not shown) and a bottom plate (not shown) are connected to the right and left body frames 3, and the right and left frames 3 are formed in a tubular shape having a rectangular cross section. An operation unit 5 is formed on the upper part of the body frame 3 of the vehicle.

As shown in FIGS. 1 and 2, a front end of the transmission case 9 is connected to a hydrostatic continuously variable transmission 7 which can be shifted to a forward side F and a reverse side R.
Are located between the right and left body frames 3,
The power of the clutch 6 is transmitted to the continuously variable transmission 7 by a transmission shaft 8 disposed between the right and left body frames 3.

[Structure Related to Transmission Pedal] Next, the structure of the transmission pedal 13 for shifting the continuously variable transmission 7 to the forward side F and the reverse side R will be described. As shown in FIGS. 1 and 2, the support shaft 11 is fixed to the lateral outside of the right body frame 3, the boss member 13 a is rotatably fitted on the support shaft 11, and the forward pedal portion 13 f is connected to the boss 13 f. It is fixed to the member 13a and extends forward of the fuselage, and the reverse pedal portion 13r
Is fixed to the boss member 13a, extends to the rear of the body, and is capable of swinging around the support shaft 11 (the boss member 13a, the forward and reverse pedal portions 13f, 13f).
r) is configured.

As shown in FIGS. 2, 3 and 4, an operation arm 19 is fixed to the trunnion shaft 12 of the continuously variable transmission 7 between the right and left body frames 3. Reference numeral 22 protrudes laterally outward from the opening 3 a of the right body frame 3. As shown in FIGS. 2, 3, and 4, the operation arm 14 is fixed to the boss member 13a, the linkage rod 16 is connected to the operation arm 14, and the vibration-proof rubber 15 is attached to the end of the linkage rod 16. Connecting portion 1 of boss member 18 externally fitted to vibration-proof rubber 15
8a is connected to the operation shaft 22.

As shown in FIGS. 3 and 2, between the right and left body frames 3, an arm 21 is swingably supported around a horizontal axis P1 of the continuously variable transmission 7, and a roller is attached to the arm 21. 21a is provided. Operation arm 1
The arm 21 is urged by a spring 20 in a counterclockwise direction in FIG. 3 so that the roller 21a is pressed by the V-shaped cam portion 19a. As shown in FIG. 2, a bracket 17 is swingably supported around a horizontal axis P2 on the outer side of the right body frame 3, and a damper 23 is connected between the bracket 17 and the operation arm 14. A stopper 24 for determining the limit of the depressing operation of the forward pedal portion 13f and a stopper 25 for determining the limit of the depressing operation of the reverse pedal portion 13r are fixed to the laterally outer side of the right body frame 3.

With the above structure, the forward pedal portion 13
By stepping on f, the continuously variable transmission 7 (trunnion shaft 12) is shifted to a higher speed side on the forward side F via the linking rod 16, and by stepping on the reverse pedal portion 13r, the link rod is operated. A first linking mechanism is configured such that the continuously variable transmission 7 (trunnion shaft 12) is shifted to a high speed side on the reverse side R via the gear 16. In this case, the abrupt depression of the forward and reverse pedal portions 13f, 13r is reduced by the damper 23, and the continuously variable transmission 7 (trunnion shaft 12) and the transmission pedal 1 are moved by the arm 21.
3 is biased to the neutral position N, and the vibration of the continuously variable transmission 7 (trunnion shaft 12) is not transmitted to the transmission pedal 13 by the vibration-proof rubber 15.

[Structure Related to Holding Mechanism] Next, the speed change lever 2
6, the transmission pedal 13 and the continuously variable transmission 7 are moved to the forward side F.
The structure of the holding mechanism for holding the desired shift position will be described. As shown in FIGS. 6 and 7, a support member 27 having a rectangular shape in a side view and a flat plate shape is provided.
A support plate 28 is fixed to a support rod 27a fixed to the support rod 27a. One end of the operation shaft 30 is rotatably supported by the boss 28a of the support plate 28, and the opposite end of the operation shaft 30 is connected to the boss 27b of the support member 27 by friction plates 41 and 42 described later. The shaft 29a of the pressing body 29 of the pressing mechanism 61 is fitted and supported, and is fitted in a shaft support hole formed in the center of the pressing body 29 and is rotatably supported.

Support arm 27 fixed to support member 27
The linking arm 34 is swingably supported around the horizontal axis P4 of FIG. 3C, a bracket 44 having a long hole 44a is fixed to the tip of the linking arm 34, and the operating arm 35 rotates relative to the operating shaft 30. A link rod 36 is fitted freely over the operation arm 35 and the link arm 34. As described later, the pin 13c of the bracket 13b fixed to the reverse pedal portion 13r is inserted into the long hole 44a of the bracket 44, and the link arm 34 and the reverse pedal portion 13r are linked.

A support member 31 formed in an L-shape when viewed from the front is externally fitted to the operation shaft 30 and fixed by a spring pin 32. The transmission lever 26 is swingably supported around the axis P3, and the speed change lever 26 is fixed to the support member 31.
A ring member 37 having a pin 37 a is slidably fitted on the operation shaft 30, and the pin 33 a of the operation arm 33 is engaged with the ring member 37. A spring 39 is provided to bias the shift lever 26 and the operation arm 33 in the counterclockwise direction in FIG. 7 (the direction in which the pin 37a is separated from the operation arm 35), and the shift lever 26 is moved to the lever guide 38 (see FIG. 10). The spring 43 biasing toward the neutral position N) is connected across the support plate 28 and the operation arm 33.

6, 7, and 9 are states in which the shift lever 26 is operated to the neutral position N of the lever guide 38, and the pin 37a is separated from the operation arm 35 to the right in FIG. ing. From this state, the shift lever 26 is moved from the neutral position N along the lever guide 38 to the forward shift path 38.
a, the ring member 37 is operated by the operation arm 33.
And the pin 37a is slid to the left in FIG.
The pin 37a comes into contact with the operation arm 35 from below. From this state, the shift lever 26 is moved to the forward shift path 38.
a, the shift lever 26 operates the operating shaft 3.
0 and the pin 37a are integrally rotated.
The operation arm 35 is rotated integrally with the operation shaft 30 by the pin 37a.

The first and second friction plates 41 and 42, the pressing mechanism 61, and the second linking mechanism for mechanically linking the shift lever 26 and the shift pedal portion 13 configured as described above.
A holding mechanism 60 including the urging means 62 is provided.

The first and second friction plates 41 and 42 are configured as follows. As shown in FIGS. 7, 8, and 9, a plurality of first friction plates 41 are loosely fitted to the left side of the paper of FIG. 7 of the operation shaft 30, and the first friction plates 41 are connected to the support member 27. Support rod 27a for connecting to support plate 28
The first friction plate 41 is in a position fixed state together with the support member 27 and the support plate 28 because the first friction plate 41 is provided in a penetrating state. The plurality of second friction plates 42 disposed between the first friction plates 41 are also loosely fitted to the operation shaft 30 so as to be relatively rotatable. The second friction plate 42 is engaged with the pin 31 a formed so as to protrude from the support member 31 and is fixed to the support member 31. Therefore, the first friction plate 41 in a fixed position and the second friction plate 42 fixed to the support member 31 that is rotated integrally with the shift lever 26 are:
They can rotate relative to each other. The first friction plate 41 and the second friction plate 42 arranged as described above are
1 and the pressing body 29 are configured to be switchable between a state of being pressed by the pressing mechanism 61 and a state of being pressed by the releasing mechanism 80.

The pressing mechanism 61 for pressing the first friction plate 41 and the second friction plate 42 against each other is configured as follows. That is, the pressing mechanism 61 includes a pressing body 29 provided with a pressing plate 29b against the first friction plate 41 and the second friction plate 42, and a rotating lever that presses the pressing body 29 by rotation about the fixed fulcrum P0. 70.

The pivot lever 70 includes a fulcrum pin 71 which engages with a notch 27B formed in a base bracket 27A attached to the support member 27, and a pressing member 29.
And a locking pin 72 that engages with a notch 29c formed in the shaft 29a.
A locking hole 73 for locking one end of a tension spring serving as the urging means 62 is provided near the end opposite to 1.
The pivoting lever 70 thus configured can be pivotally operated with the axis of the fulcrum pin 71 as a fixed fulcrum P0 at the center of rotation, and the urging force of the urging means 62 causes the pressing body 29 to rotate. Is pressed toward the friction plates 41 and 42. At this time, the axis of the fulcrum pin 71 and the locking pin 72
Is the distance L2 from the axis of the fulcrum pin 71 to the center of the locking hole 73, and the fulcrum pin 71
Is set to be sufficiently smaller than a distance L3 from the shaft center to a release action point by a release mechanism 80 described later.

That is, the ratio of the distance L1 to the distance L2 is determined by the urging force applied to the rotating lever 70 and the pressing body 2
Since the ratio is equal to the acting force with respect to No. 9, setting the distance L1 to a sufficiently small value can secure a desired pressing force with a relatively small urging force and a compact structure. Therefore, the present invention employs the following structure as a means for setting the distance L1 as small as possible. In other words, when the rotation lever 70 is configured to be freely rotatable, for example, when the rotation lever 70 is simply supported by the fitting structure of the pivot shaft and the boss on the base bracket 27A provided on the support member 27, When a dimension corresponding to 1/2 of the outer diameter is required in the range of the distance L1, and a locking structure is formed by the locking pin 72 and a shaft hole provided in the shaft center of the pressing body shaft portion 29b. A dimension corresponding to 1/2 of the shaft diameter of the pressing body shaft portion 29b having the shaft hole is required in the range of the distance L1. In the present invention, the pivot portion formed on the base bracket 27A has the same depth as the outer diameter of the fulcrum pin 71 so as to reduce the unnecessary portion of the boss portion and the shaft diameter portion from the dimension of the distance L1. Cutout 27B
And a pressing body shaft portion 2 as a connecting portion with the locking pin 72.
9b is also formed with a cutout portion 29c having a depth substantially equal to the outer diameter of the locking pin 72. In the engaged state with the notches 27B and 29c, each of the pins 7
1 and 72, the axis of the fulcrum pin 71 is the base bracket 2
In this state, the center of the locking pin 72 is closer to the fulcrum pin 71 than the center of the pressing body shaft portion 29b. It is in a state of being biased.

A tension spring as one of the urging means 62 whose one end is locked in the locking hole 73 of the rotary lever 70 is a bolt / nut as a pressure adjusting means 63 whose other end is attached to the support plate 28. , And the pulling urging force can be changed by rotating the nut.

[Release Mechanism Related Structure] As shown in FIGS. 6, 7, and 8, the release mechanism 80
The bending rod-shaped contact member 74 is fixed by welding, and the cylindrical boss-shaped rotary operation body 4 is provided around the horizontal axis P5 of the support member 27.
5 is rotatably supported, and an operation cam body 45a in the form of a round bar is provided on the outer periphery of the rotary operation body 45 so that the center line 45L of the operation cam body 45a is brought into contact with a contact portion 75 of a contact member 74 at the tip of the rotary lever 70.
Is welded and fixed in a state of crossing the center line 75L at an angle. In this state, when the rotary operation body 45 is rotated clockwise in the direction of arrow a shown in FIG. 8, the operation cam body 45a moves in the direction of arrow a, and pushes the contact member 74 in the direction of arrow b to attach Pushing the rotating lever 70 back in the direction opposite to the biasing direction of the tension spring of the biasing means 62,
The pressing state of the first and second friction plates 41 and 42 by the pressing body 29 is released. As described later, the second operation of the rotary operation body 45
The arm 45b and the side brake pedal 10 (an example of a brake operating tool) are linked, and the side brake pedal 10
The above-described releasing operation is performed by the stepping-in operation.

[Side Brake Pedal] As shown in FIGS. 2 and 11 (a), a support shaft 47 is fixed to the lateral outside of the right body frame 3, and a pair of boss members 48 are rotatable about the support shaft 47. The right and left side brake pedals 10 are fixed to the right and left boss members 48, respectively. Right and left side brakes (not shown) for independently braking the right and left rear wheels 2 are provided, and the right side brake pedal 10 and the right side brake are mechanically linked to each other. The side brake pedal 10 and the left side brake are mechanically linked, and a spring 54 for biasing the right and left side brake pedals 10 to the return side is provided.

As shown in FIG. 11 (a), an operation arm 49 is swingably supported around the horizontal axis P6 of the right body frame 3, and as shown in FIGS.
A link rod 50 is connected across the second arm 45b and the operation arm 49. As shown in FIG. 11A, each of the right and left boss members 48 is provided with an arm 48 a having a different length, and the link 51 connected to the operation arm 49 and the right boss member 48 The arm 48a and the arm 48a of the left boss member 48 are connected by a pair of links 52 and pins 53.

With the above structure, as shown in FIGS. 1, 6, and 7, the shift lever 26, the operating shaft 30, the cam plate 29a, the spring 40, the first and second friction plates 41 and 42, and the link arm 34.
The linking rod 36 and the like are supported by the support member 27 to form a single unit.

As shown in FIGS.
3, the support member 27 is fixed to the body by bolts 55, a lever guide 38 is provided, and the pin 13c of the bracket 13b of the reverse pedal portion 13r is inserted into the long hole 44a of the bracket 44. To link the link arm 34 with the reverse pedal portion 13r. As shown in FIG. 11A, an operation arm 49, a link rod 50, links 51 and 52, and a pin 53 are provided. As shown in FIGS. 6 and 7, the link rod 50 is attached to the second arm 45b of the rotary operation body 45. Connect.

[Explanation of Operation Mode] In the state shown in FIGS. 6, 7, and 10, the shift lever 2 is set at the neutral position N of the lever guide 38.
6 is being operated, and the first force is
And the second friction plates 41 and 42 are pressed and the transmission lever 2
6, the ring member 37 and the pin 37a are slid to the right in FIG. 7 by the operation arm 33, and the pin 37a is moved to the operation arm 35.
It is in a state of being separated from.

When the forward pedal 13f is depressed in this state, the continuously variable transmission 7 (trunnion shaft 12) is shifted to the high speed side of the forward F, and the linking arm 34 is operated by the reverse pedal 13r. Is pivoted upward about the horizontal axis P4, and the operation arm 35 is operated by the linkage rod 36.
Is rotated clockwise around the operation axis 30 in FIG. When the reverse pedal 13r is depressed, the continuously variable transmission 7 (the trunnion shaft 12) is shifted to the high speed side of the reverse R, and the link arm 34 is moved around the horizontal axis P4 by the reverse pedal 13r. Swinging downwards
The operation arm 35 is rotated around the operation shaft 30 counterclockwise in FIG.

Next, when the shift lever 26 is operated from the neutral position N of the lever guide 38 to the high speed side of the forward shift path 38a against the urging force of the spring 39, the ring member 37 and the pin 37a are moved by the operation arm 33. 7, the slide operation is performed to the left of the paper, and the pin 37a comes into contact with the operation arm 35 from below. Even in this state, since the first and second friction plates 41 and 42 are pressed by the urging force of the spring 40 and the frictional force is applied to the shift lever 26, the shift lever 26 is moved by the lever guide 38 against the frictional force. Forward shift path 38a
When the gear is operated to the high speed side of
0 and the pin 37a are integrally rotated in the clockwise direction in FIG. 6, and the operation arm 35 is operated by the pin 37a.
Is rotated integrally with the operation shaft 30 clockwise in FIG. Thereby, the linkage arm 34 is pivoted upward by the linkage rod 36 around the horizontal axis P4, the reverse pedal portion 13r is pivoted upward, and the forward pedal portion 13f is depressed. Similarly, the speed change pedal 13
And the continuously variable transmission 7 (trunnion shaft 12) is shifted to the high speed side of the forward side F.

Conversely, when the shift lever 26 is operated to the low speed side (the neutral position N side) of the forward shift path 38a of the lever guide 38 against the frictional force, the pin 37a is rotated counterclockwise in FIG. State, and tries to move away from the operation arm 35. In this case, since the continuously variable transmission 7 (the trunnion shaft 12) and the transmission pedal 13 are urged to the neutral position N by the arm 21 shown in FIG. 3, the transmission lever 26 is moved to the lever guide 38 against the frictional force. Forward shift path 3
8a is moved to the low speed side (the neutral position N side).
The transmission pedal 13 and the continuously variable transmission 7 (the trunnion shaft 12) are shifted to a low-speed side of the forward side F so as to follow a.

After shifting the transmission pedal 13 and the continuously variable transmission 7 (trunnion shaft 12) to the high-speed side and the low-speed side of the forward side F by the shift lever 26, release the hand from the shift lever 26 at a desired shift position. Also the spring 40, the first and second
The shift lever 26 is held at a desired shift position by the frictional force based on the friction plates 41 and 42. As a result, FIG.
The transmission pedal 13 and the continuously variable transmission 7 (the trunnion shaft 12) also move forward by the action of urging the continuously variable transmission 7 (the trunnion shaft 12) and the transmission pedal 13 to the neutral position N by the arm 21 shown in FIG. The desired shift position on the side F is held. Since the lever guide 38 is not provided with a reverse speed change path, the speed change lever 26 cannot be operated to shift the speed change pedal 13 and the continuously variable transmission 7 (the trunnion shaft 12) to the reverse side R.

When the vehicle is temporarily driven at a high speed in this state,
It is possible to depress the forward pedal portion 13f, and when the forward pedal portion 13f is depressed, the operation arm 35 is rotated clockwise in FIG.
, The stepping operation of the forward pedal portion 13f can be performed without any trouble. When the foot is released from the forward pedal portion 13f, the operation arm 35 is urged to the neutral position N by the arm 21 shown in FIG.
The gear returns to the position where it contacts the a, and returns to a state where the speed change pedal 13 and the continuously variable transmission 7 (trunnion shaft 12) are held at the desired speed change position on the forward side F.

As described above, in the state where the speed change pedal 13 and the continuously variable transmission 7 (trunnion shaft 12) are held at the desired speed change position on the forward side F, both the right and left side brake pedals 10 are depressed. Suppose you did. When both the right and left side brake pedals 10 are depressed in this manner, as shown in FIGS. 11 (a) to 11 (b),
When the pair of links 52 and the pins 53 move to the right in the drawing, the operation arm 49 is pivotally operated by the link 51, and the link rod 50 is pulled toward the operation arm 49, so that the boss member 48 and the The one arm 48a is rotated counterclockwise in FIG. 6 and the rotating lever 70 is rotated clockwise in FIG. 7 by a predetermined angle against the urging force of the urging means 62. As a result, the frictional force for holding the shift lever 26 at the desired shift position disappears by separating from the first and second friction plates 41 and 42 to the left in FIG.
The transmission lever 26 returns to the neutral position N of the lever guide 38 by the urging force of the spring 43 shown in FIG. 3, and the continuously variable transmission 7 (the trunnion shaft 1) is moved by the arm 21 shown in FIG.
2) and the action of urging the shift pedal 13 to the neutral position N, the shift pedal 13 and the continuously variable transmission 7 (trunnion shaft 12) return to the neutral position N.

When the speed change pedal 13 and the continuously variable transmission 7 (trunnion shaft 12) are held at the desired speed change position on the forward side F, the right or left side brake pedal 10
Is operated. In this case, when the right side brake pedal 10 is depressed, only the right boss member 48 and the arm 48a rotate clockwise as shown in FIG. 11A to FIG. In addition, only the pair of links 52 is bent upward around the pin 53, and the operation arm 49 is not operated to swing. When the left side brake pedal 10 is depressed, only the left boss member 48 and the arm 48a rotate in the clockwise direction on the paper as shown in FIGS. Only the link 52 is bent downward around the pin 53, and the operation arm 49 is not swung. Thus, when one of the right and left side brake pedals 10 is depressed, the frictional force for holding the shift lever 26 at the desired shift position does not disappear, and the shift lever 26 remains at the desired shift position. .

[Drive Seat-Related Structure] FIGS. 13 to 15 show a support structure for the driver's seat 90. FIG. The driving seat 90 provided in the driving unit 5 is configured such that the rear side of the driving seat 91 rotates upward around the horizontal axis P7 at the front end of the support base 92. The support base 92 includes a fixed frame 93 for the body and a link mechanism 9 for the fixed frame 93.
Lifting frame 94 movably connected via lifting 5
And a sliding frame 96 slidably movable in the front-rear direction with respect to the elevating frame 94. The horizontal axis P7 is provided at the front end of the sliding frame 96, and the driving seat 91 is mounted. Have been.

In the link mechanism 95, a connecting portion 93a with the fixed frame 93 is formed at one corner of a pair of front and rear links 95a having a substantially triangular shape, and a connecting portion with the lifting frame 94 is formed at the other corner. A connecting rod 95c for connecting the left and right links 95a is provided at the remaining one corner portion. A contact portion 97 formed by bending a part of the link 95a outward is provided at an intermediate position between the connecting portions 93a, 95a of the link 95a, and a cushion rubber provided at a lateral position of the fixed frame 93 is provided. It is configured so that impact can be mitigated by contact with the 97.

Frame frames 93 before and after the fixed frame 93
An adjustment rod 98 is provided through b. A movable spring receiver 98a is screwed to the adjusting rod 98, and the movable spring receiver 98b is configured to be movable in the length direction by rotating the adjusting rod 98. At both left and right ends of the movable spring receiving body 98a, a pair of coil springs 99 for urging the front link 95a to the upright side are hung between a connecting rod 95c connecting the left and right links 95a, By rotating the adjusting rod 98, the movable spring receiver 98a is moved back and forth, and the link 95a is moved.
The biasing force in the upright direction of the vehicle can be adjusted. Accordingly, the urging force of the coil spring 99 is applied to the lifting frame 94 while the driver is seated on the driving seat 91.
Can be set to be in a floating state.

[Another Embodiment of Release Mechanism] The structure of the release mechanism 80 is not limited to the structure shown in FIGS. 6, 7, and 8 described above, and the following structure may be employed.

As shown in FIGS. 16, 17 and 18, a bending rod-shaped contact member 74 provided at the tip of the rotating lever 70.
The supporting member 33 is extended longer than the case of the structure shown in FIG.
A bent-side release-side operation portion 81 is fixed to the lower part of the gear, and during the operation of the shift lever 26 in the forward shift path 38a, the shift lever 26 is rotated clockwise around the longitudinal axis P3 shown in FIG. When the rotary lever 70 is rotated, the rotary lever 70 comes into contact with the contact member 74 and can be operated to the release side. The contact member 74 has a contact portion 75 with the release-side operation portion 81 operated by the shift lever 26, and a support member having the same specifications as those of the embodiment shown in FIGS. A contact portion with a round bar-shaped operation cam body 45a provided on an outer peripheral portion of a rotary operation body 45 rotatably supported around a horizontal axis P5 of 27 is provided.

Therefore, the release of the pressing force by the pressing mechanism 61 by operating the side brake 10 and the shifting lever 2
6 and the pressing force can be released by both operations. The release of the pressing force by the shift lever 26 does not completely release the frictional force, but slightly reduces the frictional force so that the shift operation itself can be performed lightly. May be canceled.

FIGS. 19 and 20 show still another embodiment of the release mechanism. In this example, a rotation operation body 45 rotatably supported around the horizontal axis P5 is provided with the horizontal axis P5 provided in a fixed position with respect to the support member 27 as a first rotation axis. A round bar-shaped operation cam body 45a is provided with a center line 45L on the outer peripheral portion of the rotary operation body 45.
Are fixed by welding in an orthogonal state. At an intermediate position between the operation cam body 45a and the rotation lever 70, an intermediate rotation operation body 82 rotatably supported by a shaft 27D while being sandwiched by a bracket 27C fixed to the support member 27. Is provided. This intermediate rotation operation body 8
2 includes a cylindrical portion 83 pivotally supported by the bracket 27C, and the cylindrical portion 83 is pivotally rotatable around a center line P8 serving as a second rotation axis in a direction intersecting the horizontal axis P5. Supported. A first operating portion 84 having a round bar shape having a center line P9 orthogonal to a center line P8 of the cylindrical portion 83, and a second operating portion having a short cylindrical shape having a central line P10 parallel to the cylindrical portion 83 are provided. 85 and the operation cam body 4
By the rotation operation of 5a, the first operation unit 84 that comes into contact with the rotation operation
It rotates around the center line P8 of the cylindrical part 83,
The operation unit 85 is configured to swing the rotation lever 70 to the braking release side.

[Another Embodiment of the Invention] In the structure shown in FIGS. 2 and 4, the opening 3a of the right body frame 3 is eliminated, and the link rod 16, the damper 23 and the operating arm 14 are removed.
Is disposed between the right and left body frames 3, and the speed change pedal 13 is disposed laterally outside the right body frame 3.
And an operating arm 14 disposed between the right and left body frames 3 by an interlocking shaft (not shown) that penetrates the right body frame 3 in a rotatable state. Is also good.

In the configuration shown in FIGS. 1 and 2, the right and left body frames 3 in the form of vertical walls are eliminated, and a plurality of square pipe-shaped frames are arranged on the right side at predetermined intervals above and below the right side. The left and right body frames 3 are arranged on the left side at predetermined intervals vertically.
May be configured. With this configuration, the link rod 16 and the like are disposed in the right body frame 3 so as to pass between the upper frame and the lower frame. A belt-type continuously variable transmission (not shown) may be provided in place of the hydrostatic continuously variable transmission 7, and the hydrostatic continuously variable transmission 7 or the belt-type continuously variable transmission may be provided by an airframe. May be arranged at the front part.

[0059]

According to the first aspect of the present invention, the vehicle body can be driven at a constant speed by operating the transmission lever, and a friction plate is pressed as a holding mechanism used for the constant speed operation. At the time of urging, instead of pressing directly by the urging means, it is urged by the lever action of the turning lever that is turned around the fixed fulcrum, so that the boosting action by the lever is Utilization can reduce the urging force of the urging means for obtaining the required frictional force. Further, when the urging force of the urging means is adjusted, the pivoting lever is present in the transmission system until the adjusting action of the urging means reaches the friction plate. By utilizing the difference between the two, the amount of operation can be reduced and transmitted, contrary to the boost, and the adjustment operation itself can be easily performed.

According to the second aspect of the present invention, the provision of the release mechanism and the fact that the urging force by the urging means itself is small as described above are synergistic, so that the brake pedal is depressed when the vehicle stops. The release operation force at the time of the operation can be reduced, and a light operation can be performed.

According to the third aspect of the present invention, the distance from the fixed fulcrum of the rotating lever to the frictional plate pressing position by the rotating lever is determined by the release mechanism of the releasing lever to the rotating lever by the release mechanism. Because the distance is smaller than the distance to, in addition to the urging force itself by the urging means, it is possible to effectively use the boosting action by the lever ratio of the rotating lever,
The release operation can be performed more easily.

According to the fourth aspect of the present invention, the distance from the rotation fulcrum to the locking pin is made shorter than the total length of the rotation lever, and the lever ratio of the rotation lever as the pressing mechanism is made as effective as possible. Since, for example, an engaging hole for inserting a locking pin is formed on the center axis of the shaft portion of the pressing body, and a locking pin of the rotating lever is inserted into this engaging hole, The engagement portion can be made closer to the pivot point without being affected by the thickness of the shaft of the pressing body. As a result, a lighter release operation can be performed using the lever ratio of the rotating lever more effectively.

According to the feature of the fifth aspect, by using the notch for pivotal support configured as described above, it is not necessary for the rotary lever to have a complete shaft and boss fitting structure.
Therefore, even under the condition that the rotation fulcrum shafts have the same shaft diameter, the notch that can be formed smaller in size than using such a boss portion makes it possible to further shorten the interval between the locking pin and the notch. Also in this regard, a lighter release operation can be performed using the lever ratio of the rotating lever more effectively.

According to the sixth aspect of the present invention, the operation of the brake operating tool is transmitted to the rotating lever through two-stage rotating movement of the first rotating member and the second rotating member, thereby reducing the operating force of the brake operating tool. Between the transmitting direction and the operating direction of the rotating lever,
The operation force can be transmitted more lightly with a smooth rotational movement with little influence due to the difference in the movement direction.

According to the seventh aspect of the present invention, the influence of the urging force by the urging means is reduced not only at the time of operating the above-mentioned brake operating tool but also at the time of operating the speed change operation lever, and the speed change operation is lightened. Can be done.

[Brief description of the drawings]

FIG. 1 is an overall side view of an agricultural tractor.

FIG. 2 is a side view of the vicinity of a speed change pedal.

FIG. 3 is a side view showing the vicinity of a trunnion shaft of the continuously variable transmission.

FIG. 4 is a longitudinal sectional front view of the vicinity of a trunnion shaft of the continuously variable transmission.

FIG. 5 is a longitudinal sectional side view of the vicinity of a boss member of a link rod for linking a continuously variable transmission (trunnion shaft) and a speed change pedal;

FIG. 6 is a longitudinal sectional side view showing an operation system portion of a shift pedal and a shift lever.

FIG. 7 is a longitudinal rear view in the vicinity of a shift lever.

FIG. 8 is a perspective view of the vicinity of a release mechanism.

FIG. 9 is a sectional view of a friction plate portion.

FIG. 10 is an explanatory view of a lever guide portion.

FIG. 11 is a side view showing the vicinity of the right and left side brake pedals and showing a state where both the right and left side brakes are depressed;

FIG. 12 is a side view showing the vicinity of the right and left side brake pedals, showing a state where only the right side brake is operated and a state where only the left side brake is operated.

FIG. 13 is a side view showing a mounting portion of a driver seat.

FIG. 14 is a plan view showing a mounting portion of a driver seat.

FIG. 15 is a side view showing the fixed frame side of the driver's seat.

FIG. 16 is a longitudinal sectional side view showing another embodiment of an operation system portion of a shift pedal and a shift lever.

FIG. 17 is a vertical cross-sectional rear view showing another embodiment in the vicinity of a shift lever.

FIG. 18 is a perspective view showing another embodiment near the release mechanism.

FIG. 19 is a partial cross-sectional view showing another embodiment of the release mechanism.

FIG. 20 is a partial cross-sectional view showing another embodiment of the release mechanism.

[Explanation of symbols]

Reference Signs List 3 Body frame 7 Continuously variable transmission 10 Brake operating tool 13 Transmission pedal 13f Forward pedal portion of transmission pedal 13r Reverse pedal portion of transmission pedal 16, 18, 19 First linkage mechanism 26 Transmission lever 27 Support member 29 Pressing body 29c Notch for linking 27B Notch for pivot support 34, 36 Second linking mechanism 41 First friction plate 42 Second friction plate 45 Rotating operating body 60 Holding mechanism 61 Pressing mechanism 62 Biasing means 70 Rotating lever 71 Support pin 72 Locking pin 80 Release mechanism F Forward side R Reverse side P0 Fixed fulcrum L1 Distance from fixed fulcrum to pressing action point L3 Distance from fixed fulcrum to release operation point

Continued on the front page (72) Inventor Sada Wada 64 Ishizukita-cho, Sakai City, Osaka Prefecture F-term in Kubota Sakai Works (reference) 3D040 AA03 AA31 AB04 AC15 AC20 AC48 AD13 AF08 3J070 AA03 AA32 BA02 BA18 BA19 CB05 CD02 DA03 3J552 MA06 MA10 MA13 MA26 NA05 NA07 NB01 PA31 QC10 SA31 SB02 VA61W VD11Z VD16Z

Claims (7)

[Claims] 1. A continuously variable transmission for traveling, a speed change pedal for shifting the speed of the continuously variable transmission, a speed change lever for changing the operation position of the speed change pedal, and friction between the operation position by the speed change lever. And a continuously variable transmission device and a shift pedal are linked via a first linkage mechanism, and the continuously variable transmission device is configured to be capable of shifting operation by depressing a shift pedal. A second link mechanism for mechanically linking the shift lever, the holding mechanism, and the shift pedal; and operating the shift lever to move the shift pedal through the holding mechanism and the second link mechanism. A traveling transmission device for a working vehicle configured to be operable and capable of being held at a shift position, wherein the holding mechanism comprises: a friction plate for holding friction; and a pressing force for pressing the friction plate toward a pressure contact side. And a biasing means for applying a pressing force to the pressing mechanism against the friction plate. The pressing mechanism for the friction plate is rotated around a fixed fulcrum. A traveling transmission for a working vehicle configured to apply a pressing force by leverage of a rotating lever. 2. A release mechanism for operating a rotary lever of a pressing mechanism to release or reduce a pressing force on a friction plate by an urging means, and the releasing mechanism is linked to a braking operation of a brake operating tool. The traveling transmission of a work vehicle according to claim 1, wherein the traveling transmission is linked so as to perform a releasing operation. 3. The distance from the fixed fulcrum, which is the center of rotation of the rotating lever, to the point where the rotating lever presses against the friction plate, and the distance from the release mechanism to the release operation point on the rotating lever by the release mechanism. 3. The traveling transmission for a working vehicle according to claim 2, wherein the driving transmission is set to be smaller than the distance. 4. A rotating mechanism for rotating a pressing mechanism for pressing the friction plate against the pressure contact side around a fixed fulcrum;
A linking notch formed in the shaft of the pressing body along the pressing direction is formed by a combination with a pressing body that transmits the rotating motion of the rotating lever as a pressing action to the friction plate. The shaft center of the locking pin on the rotation lever side engaged with the notch for use is engaged at a position deviated to the lateral side closer to the rotation fulcrum than the shaft center of the shaft portion. 4. The traveling transmission for a working vehicle according to claim 1, wherein the traveling transmission is formed as follows. 5. A rotating lever which is rotated around a fixed fulcrum, comprising: a pressing mechanism for pressing the friction plate toward the pressure contact side;
The pivot lever is constituted by a combination of a pressing body that transmits the pivoting movement of the pivot lever as a pressing action to the friction plate, and a pivot portion of the pivot lever is connected to a fulcrum pin formed on the pivot lever and the fulcrum pin. And a notch for pivot provided on the fixed part so that
The notch part for pivotal support is opened toward the side where the locking pin is provided of the rotating lever, and is formed at a position offset from the locking part toward the locking pin. 5. The traveling transmission for a working vehicle according to claim 4. 6. A release mechanism for operating a rotation lever to a side for releasing or reducing a pressing force on a friction plate side by an urging means, a first rotation of a fixed position in association with a braking operation of a brake operation tool. A rotary operating body that is rotated around an axis and an intermediate rotary operating body that is rotated around a second rotary axis in a direction intersecting the first rotary axis; The rotational motion is transmitted to the intermediate rotary operation body by rotation,
4. The rotary lever according to claim 2, wherein the rotary lever is swung to the biasing force releasing side by the rotation of the intermediate rotary operating body.
A traveling transmission for a working vehicle as described in the above. 7. A release mechanism in which the speed change lever is configured to be swingable in a direction different from the speed change operation direction, and the swing operation in the different direction is transmitted as an operation force to the urging force cancel side of the rotation lever. An operation unit is provided on the shift lever,
7. The traveling device for a work vehicle according to claim 2, wherein the shift lever can be operated in the shift operation direction while maintaining the swing operation state of the shift lever in the different direction.