JPS6122018Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention comprises a hydraulic continuously variable transmission device that performs stepless speed change in forward and reverse states by operating a speed change operation shaft that rotates in forward and reverse directions, and a drive cam body. A fixed swinging arm is pivoted to the hydraulic continuously variable transmission device so as to be swingable around an axis parallel to the shaft center of the speed change operation shaft, and the swing arm is moved near and far from the speed change operation shaft. Elastically biased in one direction,
A neutral return urging mechanism configured to press the driven cam plate fixed to the speed change operation shaft with the drive cam body to return the speed change operation shaft to the neutral rotation position, and a transmission case. This invention relates to a traveling transmission device for a mobile agricultural machine equipped with a vehicle.

The above-mentioned traveling transmission uses a hydraulic continuously variable transmission to perform stepless shifting in the forward and reverse states, and also uses a neutral return biasing mechanism to bias the shift back to the neutral state. The gear shift operation to the neutral state can be performed accurately without erroneous operation, and the drive cam body of the neutral return biasing mechanism is supported movably in the distance direction with respect to the shift operation shaft using an elastic material. By supporting it on a swinging arm that is biased, it is possible to move smoothly over a long period of time without problems such as twisting when using a slide structure, etc. By equipping the transmission case with a continuously variable transmission and a neutral return biasing mechanism, it can be used satisfactorily for a long period of time without getting muddy.

However, conventional structures have been such that once the drive cam body and driven cam plate are installed at a predetermined relative position so that the shift operation shaft is biased back to the neutral state, these positions cannot be easily adjusted. Therefore, if the driving cam body or driven cam plate wears out during long-term use and their relative positions change and it becomes impossible to properly return to the neutral state and energize them, it is necessary to remove them and replace them. It became necessary to carry out the work frequently, and furthermore, the opening formed in the transmission case became larger in order to facilitate these works, which could lead to a decrease in the strength of the transmission case.

In view of the above-mentioned circumstances, the present invention allows for easy adjustment of the relative position of the driving cam body with respect to the driven cam plate from the outside of the transmission case, and also minimizes the opening formed in the transmission case for this adjustment operation. The purpose is to prevent the strength of the case from decreasing by making it small enough.

The present invention provides a traveling transmission for a mobile agricultural machine having the above-mentioned structure, in which a cylindrical transmission is rotatably fitted onto a bolt screwed into the hydraulic continuously variable transmission and can be fixed by tightening the bolt. The swing arm is pivotally supported on the shaft, and the pivot axis of the cylindrical shaft with respect to the bolt and the swing axis of the swing arm with respect to the cylindrical shaft are eccentrically supported, and the cylindrical shaft is attached to the transmission case. It is characterized by forming an opening for operating the shaft.

In other words, we focused on the fact that the position of the drive cam body of the neutral return biasing mechanism can be adjusted by changing the pivot position of the swing arm. The shaft is rotationally fixed, and the position of the swing axis of the swing arm, which is eccentric to the rotation axis, is thereby changed to adjust the position of the driving cam body relative to the driven cam plate. Therefore, it is possible to easily adjust the neutral return biasing mechanism to a desired state from outside the case, and in addition, an opening is provided in the transmission case in order to rotate and fix the cylindrical shaft from outside the case. Since the opening area required for rotating the cylindrical shaft and the opening area required for rotating the bolt are small when forming the transmission case, the opening formed in the transmission case can be made as small as possible. This makes it possible to prevent a decrease in the strength of the transmission case. As a result, we have achieved a traveling transmission device for a mobile agricultural machine that can be used very conveniently in practice as a whole.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 shows a side view of a four-wheel drive agricultural tractor, where 1 is an engine, 2 is a clutch housing containing a traveling clutch (not shown), and 3 is a hydraulic continuously variable transmission device 4 and a gear transmission device, which will be described later. (not shown); 5 is a driver's seat; 6 is a transmission case with a
is a rotating steering wheel.

The engine output is transmitted to the continuously variable transmission 4 via the traveling clutch, and after being changed to a desired speed by this transmission 4, it is transmitted to the gear transmission, and further changed to a desired speed by this gear transmission. The power is then transmitted to a pair of left and right rear wheels 7, 7 and a pair of left and right front wheels 8, 8.

The continuously variable transmission device 4 continuously changes the engine output in a forward state and a reverse state, and includes:
The operating structure of this transmission 4 will be explained based on FIG. 2.

A first plate member 9 fixed to a shift operation shaft 4a of the transmission 4 that is rotated in forward and reverse directions;
A second plate-like member 11 fixed to a rotating shaft 10 rotatably supported by the mission case 3 in parallel with the second plate member 12 is interlocked with the second plate member 11 via a rod 12. Further, at the end of the rotary shaft 10 protruding outside the case,
A gearshift foot pedal 13 that can be rotated in forward and reverse directions is fixed. Further, as the pedal 13 is rotated toward the front, the speed is changed to a high-speed forward movement state, and conversely, as the pedal 13 is rotated toward the rear, the speed is changed to a high-speed reverse movement state. As shown in FIGS. 4 and 5 (a) and (b), the pedal 13 has a foot rest part 13b for forward gear shifting and a foot rest part 13b for forward gear shifting at the front and rear ends of an arm 13a fixed to the rotating shaft 10 and facing in the front-rear direction. The reverse gear shift foot rest 13c is aligned with the horizontal axes X ₁ and X ₂ within a certain range.
It is configured to be rotatably supported around the periphery, and is capable of forward shifting by using the heel as a fulcrum and stepping on the foot rest part 13b with the toe part, and also with the toe part as a fulcrum and the foot rest being placed on the heel part. Reverse gear shifting by stepping on the footrest 13c can be performed favorably by rotating the footrests 13b and 13c.

Furthermore, a neutral return biasing mechanism is provided within the transmission case 3 to bias the shift operation shaft 4a back to the neutral rotation position.

That is, the swinging arm 15, which can freely swing around an axis parallel to the axis of the shift operation shaft 4a and is elastically biased by a spring 14 when approaching the shift operation shaft 4a in the distance direction, moves toward the shift operation shaft 4a. It is pivotally supported on the case of the device 4, is supported by the free end portion of the arm 15 so as to be movable in the distance direction with respect to the speed change operation shaft 4a, and is elastically biased to one side in the distance direction. Roller 16 as a driving cam body
is rotatably supported. The first plate-like member 9 has an inclined cam surface S1 for returning the shift operation shaft 4a from the forward state to the neutral rotation position, and an inclined cam surface _S2 for returning the shift operation shaft 4a from the reverse state to the neutral _rotation position. It is composed of a driven cam plate. The roller 16 is configured to abut and press the first plate member 9 to urge the speed change operation shaft 4a back to the neutral rotation position. FIG. 3 shows a pivot portion of the swing arm 15, in which the arm 15 is rotatably fitted onto a bolt 17 screwed into the transmission 4,
Further, the cylindrical shaft 18 is fixed by tightening the bolt 17, and the pivot shaft 18 is pivoted so that the pivot axis is eccentric with respect to the rotation axis by the bolt 17. An operating opening 19 for the cylindrical shaft 18 is formed. In addition, 20 in the figure
21 is a groove formed in the end surface of the cylindrical shaft 18 into which a tool such as a screwdriver can be inserted, and 21 is a lid that is elastically fitted into the opening 19 in a detachable manner.

Then, by adjusting the rotation of the cylindrical shaft 18, the roller 1
6 and the first plate-shaped member 9, thereby making it possible to adjust the shift operation shaft 4a so that it is correctly urged back to the neutral rotation position.

22 in the figure is a pin 24 that is inserted into a long hole 23 formed in the second plate-like member 11, and the position of the pin 24 is moved and adjusted via a rod 25 to change and adjust the shiftable range of the transmission 4. It is a swinging lever that is designed to be locked and held by the guide frame 26 at a desired swinging position.

[Brief explanation of the drawing]

The drawings show an embodiment of the traveling transmission device for a mobile agricultural machine according to the present invention, and FIG. 1 is a side view of an agricultural tractor;
FIG. 2 is a side view of the speed change operation structure, FIG. 3 is a longitudinal sectional front view of the swing arm pivot, FIG. 4 is a plan view of the pedal, and FIGS. 5A and 5B are side views of the pedal. 3...Transmission case, 4...Continuously variable transmission, 4a
... Speed change operation shaft, 9 ... Driven cam plate, 15 ... Swing arm, 16 ... Drive cam body, 17 ... Bolt, 18 ... Cylindrical shaft, 19 ... Opening, 21 ...
Lid body.

Claims (1)

[Claims for Utility Model Registration] A hydraulic continuously variable transmission device 4 that performs stepless speed change in forward and reverse states by operating a speed change operation shaft 4a that is rotated in forward and reverse directions, and a drive cam body 16. A fixed swinging arm 15 is pivoted to the hydraulic continuously variable transmission 4 so as to be swingable around an axis parallel to the axis of the speed change operation shaft 4a,
The swinging arm 15 is elastically biased to one side in the distance direction with respect to the speed change operation shaft 4a, and the driven cam plate 9 fixed to the speed change operation shaft 4a is brought into contact and pressed by the drive cam body 16, The traveling transmission device for a mobile agricultural machine is equipped with a neutral return biasing mechanism configured to return the shift operating shaft 4a to a neutral rotational position in the transmission case 3, and the hydraulic continuously variable transmission The swing arm 15 is pivotally supported on a cylindrical shaft 18 that is rotatably fitted onto a bolt 17 that is screwed into the device 4 and can be fixed by tightening the bolt 17. The rotation axis of the shaped shaft 18 and the cylindrical shaft 18
A traveling transmission device for a mobile agricultural machine, characterized in that a swing axis of a swing arm 15 is eccentric to the center of the swing axis, and an opening 19 for operating the cylindrical shaft 18 is formed in the transmission case 3. The traveling transmission device for a mobile agricultural machine according to claim 1, wherein the opening 19 is closed with a detachable lid 21.