JPS6313545Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a gear shift operating device for a tractor.

(Prior Art) It is well known that a plurality of transmissions can be operated simultaneously using one operating means. For example, in the specification of Japanese Utility Model Application No. 55-8095, a plurality of transmissions are connected to one cam disc and the cam disc is rotated to enable simultaneous operation of the plurality of transmissions.

This conventional speed change operating device is comprised of a cam disk and a cam follower device that engages with the cam disk, which are separately assembled to the vehicle body.

(Problems to be Solved by the Invention) The above-mentioned conventional system is constructed by separately assembling the cam disc and cam follower to the vehicle body, and is not integrated into a unit, and the assembly process is complicated. line. In addition, the cam disc and cam follower device are exposed to the outside, and rubber etc. tend to adhere to them, requiring constant maintenance.

Accordingly, the present invention attempts to solve the above-mentioned problems by making the speed change operating device smaller and more compact, and by making it into a unit.

(Means for Solving the Problems) The present invention is characterized in that a disc-shaped mounting plate is fixed to the tractor body, and a disc-shaped cam disc is rotatable concentrically on the mounting plate. A plurality of cam grooves are provided in the end face of the cam disk, and a cam follower device that fits into the cam grooves and is interlocked with the transmission is rotatably supported on the mounting plate. A plurality of transmission devices are configured to be operated simultaneously by rotating a disk,
A notched recess concentric with the center of rotation of the cam disc is formed in a part of the outer peripheral surface of the cam disc, and a plurality of positioning recesses corresponding to the shift operation positions of the cam disc are arranged in a row on the outer peripheral surface of the recess, and the positioning recess is arranged in a row on the outer peripheral surface of the recess. A positioning device that removably engages with the mounting plate is provided in the notch recess, and the cam disk, the cam follower device, and the positioning device are covered with a cover having a circular cross section that is fixed to the mounting plate. It is in.

(Function) According to the present invention, since the cam disc and the cam follower device are attached to the mounting plate to form a unit, assembly is completed by simply fixing the mounting plate to the vehicle body.

Further, since the cam disc and the cam follower device are covered with a cover, the adhesion of dust and the like is prevented. When installing this cover, the positioning device can be stored in the notch, so
The cover can be made to have a circular cross section so that it can be fitted onto the cam disc, thereby achieving miniaturization.

(Example) Hereinafter, with reference to the drawings, a case will be described in which an embodiment of the present invention is adopted as a traveling transmission system (auxiliary transmission mechanism and creep transmission mechanism) for a tractor. For example, it can be applied to the main transmission, PTO transmission, and even the transmission of a tiller.

What is shown in FIGS. 1 to 3 is an embodiment of the present invention, in which numeral 1 denotes a transmission case of a tractor, which constitutes the vehicle body of the tractor.

A power transmission mechanism (not shown) is provided within the transmission case 1, and a traveling system transmission is provided to this mechanism. This driving system transmission includes a main transmission that converts the power from the engine to, for example, 4-speed and reverse speed, a sub-transmission that further converts the power after the main shift to 2-speed, and a 2-speed that switches to ultra-low speed. It consists of a creep transmission. Each speed change is performed by appropriately selecting a gear train. This selection is made by selectively switching a shift means such as a shifter or a shift fork, and a predetermined gear train is constructed. The shift means is operated by means of a lever, a link mechanism, or the like.

2 is its operating means, which consists of a cam mechanism;
This allows the auxiliary transmission and creep transmission to be operated at the same time.

The operating means 2 has a mounting plate 4 fixed to the side surface of the mission case 1 with bolts 3, and a main shaft 5 projecting outward is rotatably supported on the mounting plate 4. A rotation operating lever 6 is fixed to the outer end of the main shaft 5. A flange 7 is fixed to the main shaft 5, and a cam disk 8 is attached to the flange 7 with bolts 9. Cam grooves 10 and 11 are provided at two locations on the end surface of the cam disk 8, and the cam grooves 10 and 11 have irregularities in the radial direction and are provided over a predetermined length in the circumferential direction.

One of the cam grooves 10 is for sub-shift operation, and is formed in an arc concentric with the main shaft 5 from point a to point b in the figure, and oriented toward the center from point b to point c. The area from point to point d is formed into an arc concentric with the main axis 5. The other cam groove 11 is for creep speed change operation, and is oriented radially outward from point a' to point b', oriented toward the center from point b' to point c', and oriented radially outward from point a' to point b', and oriented toward the center from point b' to point c'. The area from point ' to point d' is formed into a mountain shape with the same height so as to point in the radial direction.

The central angles between a-b and a'-b' are the same, and similarly between b-c and b'-c', and between c-d and c'-
The central angles between d′ are formed to be equal.

12 is an arm for sub-shift operation;
2 is rotatably attached to the mounting plate 4 via a support shaft 13. The support shaft 13 and the arm 12 are fixed to rotate together. A cam follower 14 or a pin is provided at the tip of this arm 12,
The cam follower 14 fits into the cam groove 10. A connecting arm 15 is fixed to the other end of the support shaft 13, and a sub-shift operation link 1 is attached to the connecting arm 15.
6 is rotatably pivotally mounted, and the link 16 is operatively connected to a protrusion 17 of a shift means of the sub-transmission device.

Reference numeral 18 designates an arm for operating a creep speed change. This arm 18 is also rotatably supported on the mounting plate 4 via a support shaft 19, and a cam follower 20 provided at the tip of the arm 18 is inserted into a cam groove 11 for creep speed change. They are mated. A connecting arm 21 is also fixed to the end of this support shaft 19, and a creep shift operation link 22 is connected to the arm 21, and the link 22 is interlocked and connected to a protrusion 23 of a shift means of the creep transmission. .

As shown in FIG. 1, the positional relationship between the sub-shift operating arm 12 and the creep shift operating arm 18 is such that the respective cam followers 14 and 20 are located at points a and a' at predetermined positions on the cam disc 8. .

A positioning and fixing means 24 is provided on the outer periphery of the cam disk 8. The means 24 is a cam disk 8
A recess 25A is formed in the circumferential direction on the arcuate outer peripheral surface 25 of the cam disc 8, that is, on a circle concentric with the rotation axis of the cam disc 8, that is, the lateral axis, and in this example, the recess 25A has a positioning part 26 corresponding to each gear shift position. It consists of four notched recesses arranged in a row at predetermined intervals, and a ratchet part 27 that removably engages with the positioning part 26.
It is equal to the central angle between c and d. The ratchet portion 27 includes a positioning arm 28 rotatably supported on the mounting plate 4, a ratchet pin 29 protruding from the tip of the arm 28, and a ratchet pin 29 that connects the pin 29 to the recess 3 of the cam disk 8.
In this example, the positioning arm 28 is parallel to the rotational axis of the cam disk 8, and a support shaft 34 fixed to the mounting plate 4 is attached to the pin 33. , other end 30
B is locked to the arm 28.

A cover 31 is made of synthetic resin and integrally molded into a bowl shape, and is fitted onto the outer periphery of the mounting plate 4 to cover the cam disc 8. Here, the cover 31 and the mounting plate 4 constitute a case on the fixed side. are doing. A seal hole 32 for penetrating the main shaft 5 is provided in the center of the cover 31, and the inner circumferential surface of the seal hole 32 is tapered in cross section so as to slide against the main shaft 5 and exert a sealing action.

The operation of the above embodiment of the present invention will be explained.

By rotating the rotation operation lever 6 in the X direction shown in the drawing, the cam follower 14 of the sub-shift operation arm 12 fitted in the point a of one cam groove 10 moves to the point b, and The cam follower 20 of the creep shift operating arm 18, which is fitted at point a' of 11, moves to point b'. Since the distance between a and b of the cam groove 10 is a circular arc, the sub-shift operation arm 12 maintains a constant position without swinging due to the rotation of the cam disk 8, but the creep shift operation arm 18 is connected to the cam groove 11. The shifter means for creep speed change is operated via the link mechanism 22 to perform a speed change operation. This shift position is ensured by the pin 29 re-engaging with the positioning portion 26.

By further rotating the cam disk 8, the auxiliary transmission operating arm 12 swings in the Y direction shown in the figure between the cam grooves 10b and 10c, and operates the auxiliary transmission via the connecting arm 15 and link 16. At the same time, the creep shift operation arm 18 swings in the Z direction along the cam grooves 11b'-c' and returns to its original position.
The swinging of each arm 15, 18 between the cam grooves 10c-d and between the cam grooves 11c'-d' is also the same,
Positioning is also the same, spring (bullet) 30
Since the engagement biasing force acts radially inward from the outer peripheral surface of the cam disk 8, the cam disk 8 does not fall.

Therefore, by rotating one operating lever 6, the sub-shift and the creep shifting are operated simultaneously, thereby improving operability and reducing the number of operating levers 6.

Further, since the cam grooves 10 and 11 are provided on a single cam disk 8, the structure is simple, and since the cam followers 14 and 20 are forced to move by the cam grooves 10 and 11, a return mechanism is not required. Improves followability.

(Effects of the invention) According to the invention, the cam disk 8, cam follower, and positioning device are mounted on the mounting plate to form a unit, so when assembling the tractor body, this unit can be attached to the tractor body. As a result, assembly lines can be achieved.

Further, since a notch is formed in a part of the outer circumference of the cam disc and the positioning device is housed in the recess, the speed change operating device can be made smaller.

Furthermore, since the cam disk, cam follower device, and positioning section are covered with a cover, there is no dust or the like attached, and maintenance is free.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially sectional side view of the first embodiment, FIG. 2 is a sectional view taken along the line of FIG. 1, and FIG. 3 is a plan view of the main part. 8...Cam disc, 10, 11...Cam groove, 1
2, 18...Operation arm, 35A...Recess, 26
...Positioning unit, 28...Positioning arm, 30
...Ammunition, 34...Spindle, 4,31...Case.

Claims (1)

[Scope of utility model registration request] A disk-shaped mounting plate is fixed to the tractor body, a disk-shaped cam disk is rotatably supported concentrically on the mounting plate, and a plurality of cam grooves are formed in the end surface of the cam disk. A cam follower device that fits into the cam groove and is operatively connected to the transmission is rotatably supported on the mounting plate, so that a plurality of the transmissions can be operated simultaneously by rotating the cam disk. A notched recess concentric with the center of rotation of the cam disc is formed in a part of the outer peripheral surface of the cam disc, and a plurality of positioning recesses corresponding to the gear change operation positions of the cam disc are arranged in a row on the outer peripheral surface of the recess, A positioning device that is removably engaged with the positioning recess is provided on the mounting plate within the notch recess, and the cam disk, the cam follower device, and the positioning device are covered with a cover having a circular cross section that is fixed to the mounting plate. A tractor speed change operation device characterized by: