JPH0538981Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] 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 for switching between high and low speeds in addition to the main transmission mechanism. For example, there is a device like the one shown in Japanese Utility Model Application Publication No. 156026/1983, but in all of these devices, the gear shift lever is shifted by moving the bullet over the fulcrum, so the gear shift is difficult. In order to hold the lever in the neutral position, it is necessary to provide a dedicated notch groove in the lever guide or use a specially shaped positioning bullet to hold the shift lever in the neutral position. In the former case, there is a particular disadvantage that the operation of the gear shift lever is no longer linear, resulting in poor operability. virtually difficult to match a neutral holding position;
Therefore, there is a problem in that the operation of the gear shift lever inevitably becomes unnatural.

[Means for solving the problem] The present invention was created in view of the above-mentioned circumstances with the aim of providing a transmission device for a working vehicle that can eliminate these drawbacks.
A transmission device for a work vehicle that performs gear change with a neutral position located at an intermediate position by a swinging operation of a gear shift lever, wherein the gear shift lever includes a flat first cam surface and a flat first cam surface. A cam plate is provided with skirt-shaped second and third cam surfaces located on both sides in the axial direction so as to be at the top, and the second and third cam surfaces are formed on the cam plate at the neutral position of the gear shift lever. A pair of pressing bodies are installed opposite each other to press the cam plate inward, and one of the pressing bodies presses the corner between the adjacent cam surfaces by swinging the gear shift lever from the neutral position. In addition, supports for supporting each of the above-mentioned pressing bodies are disposed on both sides so as to sandwich the cam plate surface, and the supports have a laminated structure on the cam plate surface. This feature is characterized in that an overlap portion is formed that overlaps the two.

According to the present invention, with this configuration, each switching state can be accurately operated and maintained through natural linear operation of the gear shift lever.

[Example] Next, an example 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. Also 3,4
5 is a front and rear wheel, 5 is a steering wheel, and 6 is a driver's seat, all of which are configured 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. Bombs 15 and 16 are stretched between the steering wheel 5 and a bracket 14, and the biasing force of the bullets 15 and 16 causes the tension to be The pulleys 12 and 13 are always biased toward the side that keeps the transmission belts 10 and 11 under tension.

On the other hand, 17 is a foot-depressable main clutch pedal, and the main clutch pedal 17 swings up and down with a swing shaft 17a as a fulcrum. One end of the is pivotally connected. The other end of the connecting rod 18 is connected to arm bodies 12b and 13b which are pivotally connected to an arm shaft 19 so as to swing together with the tension arms 12a and 13a, respectively.
The main clutch pedal 17 is depressed and the arms 12b, 13b are loosely fitted into long holes 12c, 13c drilled in the
By pushing away the tension arm 12a, 1
3a simultaneously moves 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, respectively. corresponding) 24 and 25 are the cam plate 21
are spaced apart from each other at appropriate intervals on the plate surface side, but are arranged so as to sandwich the plate surface from both sides, and their lower ends are viewed from the front, that is, axially, as shown in Figure 2. When viewed from the core direction, overlap portions 24b and 25b are formed to overlap the upper portion of the cam plate 21 in a laminated manner, and are pivotally connected 24a and 25a, respectively. The tips of these links 24 and 25 are pivotally connected to a support shaft 26 fixed to the steering column 5a, and wheels 27 and 28 (corresponding to the pressing body of the present invention) are attached to the cam plate 21. The shaft is supported by a shaft so as to face the cam surface of the shaft. And link 24,
25 and the tension pulleys 12 and 13, the tension pulleys 12 and 13 are connected to each other by the links 24 and 25 moving upward about the support shaft 26 as described later.
The transmission belts 10 and 11 are connected to each other so that the transmission belts 10 and 11 are loosened in conjunction with the downward movement of the bullets 13 against the bombs 15 and 16.

In addition, the cam surface of the cam plate 21 has a second cam surface 21a and a second cam surface 21b on both sides in the axial direction across the first cam surface 21b, which has a large span (distance) from the support shaft 21a, such that the span becomes smaller toward the end. Third cam surface 21c, 2
1d, and is formed into a substantially trapezoidal shape by the second and third cam surfaces 21c and 21d.
On the sides, recesses 21e and 21f are formed at positions close to the first cam surface 21b. As shown in FIG. 5B, when the gear shift lever 20 is located at the neutral position, the tension pulley 1
2 and 13 are fitted into the recesses 21e and 21f, respectively, and in this state, both links 2
As described above, the cam plates 21 are set so as to be moved upward against the bullets 15 and 16, and the power is cut off in which the transmission belts 10 and 11 are relaxed. , bullet 1 from wheels 27 and 28
It receives urging forces 5 and 16 from both sides so as to be pressed and held at the neutral position.

When the shift lever 20 is switched from this neutral state to the low speed side, the wheel body 27 exits the recess 21e and moves between the second cam surface 21c and the first cam surface 21b, as shown in FIG. 5A. The wheel body 28 crosses over the mountain at the formed corner portion and reaches the first cam surface 21b, and the wheel body 28 comes out from the recessed portion 21f and goes down the third cam surface 21d as it is.In this state, the link 2
4 is maintained in an upward moving state, and the high-speed side transmission belt 10 remains relaxed. On the other hand, when the link 25 moves down the third cam surface 21d, the tension pulley 13 moves downward under the biasing force of the bullet 16 and tensions the transmission belt 11, thereby increasing the power at low speeds. (In this case, in the embodiment, the link 25 is slightly spaced apart from the third cam surface 21d).
In addition, when the gear shift lever 20 is operated to the high speed side, the operation is reversed, and the transmission belt 11 remains relaxed, and the transmission belt 10 is tensed, so that power transmission at the high speed side is achieved. (See Figure 5C). And in such a shift change,
Even though the relative positions of the cam body 21 and the links 24, 25 change, the above-mentioned overlap portions 24b, 25b formed on the links 24, 25 are set so that a portion that overlaps the cam plate 21 still remains.

Incidentally, the first cam surface 21b has a substantially flat shape, and in a low and high speed operating state, the ammunition 15, 16
The wheels 27 and 28, which are pressed against the first cam surface 21b under the urging force of , are held at approximately the center position of the first cam surface 21b. Further, the stopper of the shift lever 20 is provided by a stopper 29 protruding from the connecting plate 23 for the low-speed operation side, and by the stopper 29 provided protruding from the connecting plate 23 for the high-speed operation side, when the connecting plate 22 comes into contact with the displaced shift lever 20. It is set so that it becomes a stopper.

Furthermore, in this embodiment, the front wheel 3 has a boss portion 3
a is fitted onto the axle 30 in a state where it is prevented from rotating by a key 31, and the outer surface of the boss portion 3a has a diameter larger than that of the boss portion 3a and a center portion that is larger than the axle 30. A collar portion 32 in which a small diameter bolt hole 32a is drilled is integrally fixed. When replacing the front wheel 3, use the gear puller 3.
The front wheel 3 can be pulled out from the boss part 3a by locking the claw part 33a of No. 3 on the outer circumferential part of the flange part 32. On the other hand, when installing the front wheel 3, the axle 30 can be assembled until it hits the flange part 32. The mounting position of the front wheel 3 can be determined.

Furthermore, in the planting section 2, the side float 34 to be attached is attached to the side float main body 3.
4a and an auxiliary float 34b that is removably attached to the outside thereof.In this case, the attachment structure is as follows. That is, the bolt 35 is attached to the float body 34a.
A cylindrical portion 36 is integrally provided on the bracket 35 fixed at point a, while an auxiliary float 34b
A connecting rod 39 is integrally provided and protrudes from a cylindrical portion 38 provided on a bracket 37 which is fixed to the bracket 37 through a bolt hole 37a. By fitting this connecting rod 39 into the cylindrical portion 36, the auxiliary float 34b is removably attached to the float body 34a.
is formed, and this flat part 39a is connected to the bolt 4.
By tightening using 0, the rotation of the auxiliary float 34b around the connecting rod 39 is prevented. Moreover, the auxiliary float 34b installed in this way has an appropriate gap L between it and the float main body 34a, and the mud that is pushed away by the leading edge of the side float 34 when the aircraft is running is not only left and right but also By actively dispersing and escaping from this gap L, it is possible to minimize as much as possible the phenomenon of ripples on the rice field that have a negative impact, such as knocking down already planted seedlings. Although this gap L varies depending on the field conditions, it is preferably about 7 to 13 mm in a normal field.

In the embodiment of the present invention constructed as described above, the sub-shifts between high speed, neutral, and low speed are accomplished by the switching operation of the shift lever 20, as described above. Lever 2
0 lever operation is direct, each shift position can be distinguished step by step, and each shift position can be maintained.

That is, in the embodiment of the present invention, the second and third cam surfaces 21c and 21d of the cam plate 21 provided on the speed change lever 20 are attached to the tensioning bullets 15 and 16 at intermediate positions between high and low speeds. It is held in this state by being pinched and held from both sides by the force, so there is no need to provide a guide groove dedicated to the neutral position as in the past, and it can be operated in a straight line. Even if there is a problem, it can be reliably held in the neutral position. Moreover, when changing gears, one of the wheels 27, 28 is formed between the second and third cam surfaces 21c, 21d and the first cam surface 21b from the pinched state from both sides. The lever load at this time is as follows:
For example, when operating from low speed to neutral to high speed, characteristic load changes occur when changing from low speed to neutral and when changing from neutral to high speed, as shown in FIG. And since this change is reliably reproduced at the lever position regardless of the lever change from low speed to high speed or high speed to low speed, it is easy to operate, and the operation feels like crossing the fulcrum of a bullet. This eliminates the possibility of misalignment, greatly improving the operability of lever operation, and greatly contributing to the prevention of operational errors.

Moreover, in this case, the links 24 and 25 supporting the wheels 27 and 28, respectively, are arranged on both sides of the cam plate 21 so as to overlap the cam plate 21 from both sides of the cam plate surface. When operating the gear shift lever 20, even if the direction of the force applied by the operator deviates from the correct direction of lever operation and the cam plate 21 attempts to deform to the deviated side, the cam plate 21 is deformed by the links located on both sides. 24, 25 restricts and prevents the wheels 27, 28 from coming out from the cam surface, and as a result, the wheels 27, 28 always roll reliably on the cam surface. This makes it possible to avoid dangers such as the sudden activation of the clutch due to disengagement, resulting in extremely high safety and reliability.

[Operations and Effects] In summary, the present invention is constructed as described above, so that the gear shift lever is configured such that the second and third cam surfaces formed on the cam plate are pushed inwardly from both sides by a pair of pressing bodies. By being pressed towards the neutral position, it is held in the neutral position, and therefore,
There is no need to provide a guide groove exclusively for the neutral position, and a linear lever operation is sufficient. In addition, when operating the lever, the lever resistance changes due to the action of the pressing body over the mountain at the corner between adjacent cam surfaces, so the lever sensation for shifting gears is different from that of gear shifting. This occurs in accordance with the position, so that gear shifting with a neutral position in the middle can be done naturally and reliably.

Furthermore, the cam plate has a pair of supports that support each pressing body, which sandwich the cam plate surface from both sides and overlap, so when the lever is operated, the direction may deviate from the normal operating direction. Also, the cam plate swings and displaces while being guided by both supports, and the cam plate is reliably prevented from deforming and the pressing body coming off the cam surface, and the pressing body is always aligned with the cam surface. As a result, the problem of the pressing body coming off the cam surface can be prevented, resulting in extremely high safety and reliability.

[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, Fig. 3A, B is a front view of the same as above, an enlarged view of the main parts, FIG. 4 is an enlarged view of the cam plate, FIG. The figure is an action diagram showing changes in lever load.
Fig. 7 is an explanatory diagram showing the boss portion of the front wheel, Fig. 8 is a sectional view of the same as above, Fig. 9 is a plan view of the side float, and Fig. 10 A and B are partial cutaways of the side float body and auxiliary float, respectively. A cutaway side view and FIGS. 11A and 11B are an action explanatory view and a longitudinal cross-sectional view of a main part, respectively, showing the assembled state of the auxiliary float. In the figure, 1 is a traveling aircraft, 15 and 16 are ammunition aircraft, and 17
is the main clutch pedal, 20 is the gear shift lever, 21 is the cam plate, 21b is the first cam surface, 21c, 21d are the second and third cam surfaces, 24, 25 are the links, 24
b and 25b are overlap portions, and 27 and 28 are rings.

Claims (1)

[Scope of utility model registration request] A transmission device for a work vehicle that performs gear change with a neutral position located in an intermediate position by a swinging operation of a gear shift lever, wherein the gear shift lever includes a flat first cam surface and the first cam surface. A cam plate is provided with foot-shaped second and third cam surfaces located on both sides in the axial direction so that the top of the cam plate is formed, and the second and third cam surfaces are formed on the cam plate at the neutral position of the gear shift lever. A pair of pressing bodies are installed opposite each other to press the cam plate inward by contacting the respective faces, and one of the pressing bodies moves between the adjacent cam surfaces by swinging the gear shift lever from the neutral position. The configuration is such that the corner part is crossed over the mountain to reach the first cam surface, and supports for supporting each of the above-mentioned pressing bodies are disposed on both sides so as to sandwich the cam plate surface, and the supports are laminated on the cam plate surface. 1. A transmission device for a work vehicle, characterized in that an overlap portion is formed to overlap in a shape.