JPH032054Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission device for working vehicles such as rice transplanters, fertilizers, transplanters, etc.

[Problems to be solved by the prior art and the invention]

Generally, some work vehicles of this type are provided with an auxiliary transmission mechanism that performs high-speed and low-speed switching in addition to the main transmission mechanism. There are such devices, such as those shown in Japanese Utility Model Application Publication No. 58-156026, but all of these devices shift the gear shift lever by moving the bullet over the fulcrum. To keep the gear shift lever in the neutral position,
It is necessary to hold the gear shift lever in the neutral position by providing a dedicated notch in the lever guide or by using a specially shaped positioning device. Therefore, in the former case, the gear shift lever cannot be operated in a straight line. In addition, it is difficult to match the position beyond the fulcrum with the neutral holding position by the notch groove or the positioning bullet, and for this reason, the shift lever This has become a problem because it has the disadvantage that the operation inevitably becomes unnatural.

[Means to solve the problem]

In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a transmission for a work vehicle that can eliminate these shortcomings. The transmission device for a work vehicle is configured to perform gear shifting at a position, and the cam plate provided on the gear shift lever is in contact with the cam surface from both sides at the neutral position of the gear shift lever, and the cam plates are moved inwardly. A pair of pressing bodies are provided facing each other, and the cam surface of the cam plate is formed with a surface on which the pressing bodies move over a mountain when the gear shift lever is operated from a neutral position. It is something.

With this structure, this invention enables each switching state to be accurately operated and maintained by linear and natural operation of the gear shift lever.

〔Example〕

Next, one embodiment of the present invention will be described based on the drawings. In the drawings, reference numeral 1 denotes a traveling body of a riding type rice transplanter, and a planting section 2 is attached to the rear of the traveling body 1 so as to be movable up and down. 3 and 4 are front wheels and rear wheels, 5 is a steering wheel, and 6 is a driver's seat, all of which are constructed in the conventional manner.

7 is a drive pulley on the engine side, and 8 and 9 are driven pulleys of different diameters on the transmission side.
0 and 11 are hung respectively. 12,13
is a tension pulley, and the tension arms 12a, 13a of the tension pulleys 12, 13
and a bracket 14 that is integrally fixed to the steering column 5a side of the steering wheel 5.
Due to the biasing forces of 5 and 16, tension pulley 1
2 and 13 are biased toward the side that keeps the transmission belts 10 and 11 under constant tension.

On the other hand, 17 is a foot-type main clutch pedal, and the main clutch pedal 17 has a swing shaft 17a.
One end of a connecting rod 18 is pivotally connected to the boss portion of the main clutch pedal 17. The other end of the connecting rod 18 is connected to arm bodies 12b and 13 which are pivotally connected to an arm shaft 19 so as to be able to swing together with the tension arms 12a and 13a, respectively.
It fits loosely into long holes 12c and 13c drilled in b.
Depress the main clutch pedal 17 and the arm body 12b,1
By pushing 3b away, tension arm 12
a and 13a simultaneously move downward against the bombs 15 and 16, thereby loosening the transmission belts 10 and 11, thereby cutting off power transmission.

Reference numeral 20 denotes a speed change lever according to the present invention, and the base end of the speed change lever 20 is integrally fixed to a cam plate 21 that swings back and forth about a support shaft 21a. Further, the lower ends of connecting plates 22, 23 are pivotally connected 22a, 23a to the tension arms 12a, 13a.
Links 24 and 25 are pivotally connected to the upper ends of 2 and 23, respectively. The tips of these links 24 and 25 are pivotably connected to a support shaft 26 fixed to the steering column 5a, and the wheels 27 and 28 (corresponding to the pressing body of the present invention) are connected to cams. It is mounted on a shaft so as to face the cam surface of the plate 21. As will be described later, the links 24 and 25 and the tension pulleys 12 and 13 are
Tension pulleys 12 and 13 are moved up by moving links 24 and 25 about support shaft 26 as a fulcrum.
are interlocked and connected so as to move downward against the bombs 15, 16 and relax the transmission belts 10, 11. Further, the cam surface of the cam plate 21 is connected to the support shaft 21.
On both sides of the first cam surface 21b, which has a large span from a, a second cam surface 21b whose span becomes smaller toward the ends;
It is formed into a substantially trapezoidal shape by the third cam surfaces 21c and 21d, and furthermore, the first cam surface 21 is formed on the second and third cam surfaces 21C and 21d side.
Concave portions 21e and 21f are formed in portions adjacent to b. As shown in FIG. 5B, when the shift lever 20 is located at the neutral position, the tension pulleys 12 and 13 are moved into the recesses 21e and 2, respectively.
I'm starting to immerse myself in 1F. In this state, both links 24 and 25 are set to be in a power-cut state in which they are moved upward against the bombs 15 and 16 and the transmission belts 10 and 11 are relaxed, as described above. In this case, the cam plate 21 receives the urging force of the bombs 15, 16 from the wheels 27, 28 so as to be clamped from both sides, and is held at the neutral position. When the gear shift lever 20 is switched from this neutral state to the low speed side, the wheel body 27 exits the recess 21e and crosses the mountain to reach the first cam surface 21b, as shown in FIG. 5A, and the wheel body 27 comes out from the recess 21f and reaches the third cam surface 21d.
You will be able to descend as it is. For this reason link 24
is maintained in an upward moving state, and the transmission belt 10 on the high speed side
remains relaxed, while the tension pulley 13 moves downward under the biasing force of the bullet 16 as the link 25 moves down the third cam surface 21d, tensioning the transmission belt 11. Therefore, power transmission is achieved in a low speed state (in this case, in the embodiment, the link 25 is connected to the third cam surface 21).
It is slightly separated from d. ). In addition, when the gear shift lever 20 is operated to the high speed side, the operation is the opposite, and the transmission belt 11 remains relaxed, and the transmission belt 10 is tensed, so that power is transmitted at the high speed side. It's getting old.

Here, the first cam surface 21b is flat, and the wheels 27, 28 which are pressed against the first cam surface 21b under the urging force of the projectiles 15, 16 in the low-high-speed operation state, It is adapted to be held at the center position of the first cam surface 21b. In addition, the stopper of the gear shift lever 20 is as follows for the low speed operation side.
This is achieved by a stopper 29 protruding from the connecting plate 23, and on the high speed operation side, the connecting plate 22 itself is set to come into contact with the displaced shift lever 20 and act as a stopper.

In the embodiment of the present invention constructed as described above, the sub-shifts between high speed, neutral, and low speed are performed by switching the shift lever 20, as described above. In,
The lever operation of the shift lever 20 is linear, and each shift position can be distinguished in stages, and each shift position can be maintained.

That is, in the present invention, the cam plate 21 provided on the shift lever 20 is attached so as to be clamped from both sides by the biasing force of the tension bullets 15 and 16 at a neutral position between high and low speeds. Therefore, there is no need to provide a guide groove dedicated to the neutral position as in the past.
Even when operating in a straight line, the neutral position can be maintained reliably. Moreover, when changing gears, one of the wheels 27, 28 is displaced from the above-mentioned state where they are clamped from both sides so as to cross over the cam surface 21b, and the lever load at this time is
When operating from low speed → neutral → high speed, as shown in Figure 6, there is a characteristic load change when moving from low speed to neutral and when moving from neutral to high speed, and this change is different from low speed → high speed, Since it is reliably reproduced at the lever position regardless of the lever change from high speed to low speed, it has excellent operability and does not cause deviations in the operating feeling like when moving over the fulcrum of a bullet. This greatly improves the operability of lever operation and greatly contributes to preventing operational errors.

Moreover, in the embodiment, the biasing force for holding the gear shift lever 20 in the neutral position is provided by effectively utilizing the belt tensioners 15 and 16, so that in addition to the dual use of parts, The structure can be simplified.

[Effect]

In summary, since the present invention is constructed as described above, the gear shift lever is held in the neutral position by the cam plate being pressed inward from both sides by a pair of pressing bodies. Therefore, it is possible to operate the lever linearly without providing a guide groove exclusively for the neutral position. Moreover, when operating the lever, the lever resistance changes due to the over-hill action of the pressing body, so the lever sensation for shifting gears occurs in correspondence with the gear shifting position. This means that gear changes with a neutral position in the middle can be done naturally and reliably.

[Brief explanation of the drawing]

The drawings show an embodiment of the transmission device for a working vehicle according to the present invention, in which Fig. 1 is an overall side view of the rice transplanter, Fig. 2 is a side view of the speed change lever section, and Fig. 3 is the same as above. The front view, Figure 4 is an enlarged view of the cam plate, Figures 5A, B, and C are action explanatory diagrams showing the states of switching to low speed, neutral, and high speed positions, respectively, and Figure 6 is a diagram showing changes in lever load. It is. In the figure, 1 is the traveling body, 2 is the planting part, 5 is the steering wheel, 15 and 16 are the bullets, 17 is the main clutch pedal, 20 is the gear shift lever, 21 is the cam plate, and 27 and 28 are the wheels. .

Claims (1)

[Scope of utility model registration request] This is a transmission device for a work vehicle that performs gear shifting with a neutral position located at an intermediate position by lever operation of a gear shift lever. A pair of pressing bodies are installed opposite each other to press the cam plates inwardly, and the cam surfaces of the cam plates allow the pressing bodies to move over a mountain by operating the gear shift lever from the neutral position. A transmission device for a work vehicle, characterized in that a surface is formed to