JPH08118976A - Four-wheel drive working vehicle - Google Patents

Abstract

PURPOSE: To carry out highly reliable setting of two states - one state that a front wheel speed change gear is operated to change over to a speed increasing state at the time of turning and the other state that it is not operated to change over to it on a four-wheel drive working car furnished with the front wheel speed change gear free to operate to change over to a standard state and to the speed increasing state. CONSTITUTION: This working car is furnished with a change-over operating part 23 to operate to change a front wheel speed change gear to over to a standard state and a speed increasing state and an operating member 12 to be operated to displace by steering operation of a front wheel, and a first contact part 23a is fixed on the change-over operating part 23. When the operating member 12 is operated to displace, it makes contact with the first first contact part 23a and supports a second contact part 24 on the operating member 12 free to operate to oscillate it to a working position where the changeover operating part 23 is operated to push it from a standard state position A to a speed increasing state position B and to a non-working position where the operating member 12 does not make contact with the first contact part 23a even when the operating member is operated to displace and the changeover operating part 23 is left at the standard state position A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a traveling system in a four-wheel drive type work vehicle such as a riding type rice transplanter and an agricultural tractor.

[0002]

2. Description of the Related Art In a four-wheel drive type work vehicle such as a passenger type rice transplanter or an agricultural tractor, for example, the actual construction machine 63-19403 is used.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 0, a front wheel transmission capable of switching operation between a standard state in which front wheels and rear wheels are driven at substantially the same speed and an increased state in which front wheels are driven at a higher speed than rear wheels. Is equipped with a transmission system to the front wheels, the front wheel transmission is configured to be switched from the standard state to the speed-up state when turning while steering the front wheels, so that a smooth small turn can be performed. There is something.

In this case, an operating shaft (45 in FIG. 4 of the publication) which is driven to rotate in association with the steering operation of the front wheels and a cam member (44 in FIG. 4 of the publication) are provided. When the front wheels are steered from the straight ahead position to the right or left by a set angle or more, the operation shaft and the cam member cause the shift shaft (31 in FIG. 4 of the publication) and the shift fork (4 of the publication).
By pressing 30) in the figure, the front wheel transmission is switched from the standard state to the speed increasing state.

[0004]

Problems to be Solved by the Invention
In the four-wheel drive work vehicle disclosed in Japanese Patent No. 94030, it is possible to set a state in which the front wheel transmission is not switched to the speed increasing state and remains in the standard state during turning. In this case, the cam member (44 in FIG. 4 of the publication) is fitted onto the operation shaft (45 in FIG. 4 of the publication) by a spline structure, and the cam member slides along the operation shaft. Operate the cam member to shift shaft (31 in FIG. 4 of the publication).
When the vehicle is turned, the front wheel transmission is set so as not to be switched to the speed-increasing state when the vehicle is turned.

However, in the above-mentioned structure, when the front wheel transmission is set to the two states, that is, the switching operation to the speed increasing state and the non-switching operation, the cam member is slid along the operating shaft. Because I am configuring
If insufficient lubrication occurs between the cam member and the operating shaft, a twisting phenomenon may occur, and the cam member may not be smoothly slid along the operating shaft. The present invention relates to a four-wheel drive work vehicle equipped with a front wheel transmission,
An object of the present invention is to obtain a configuration in which two states, that is, a state in which the front wheel transmission is switched to a speed-up state and a state in which the front wheel transmission is not switched are always smoothly set during turning.

[0006]

A feature of the present invention is that the four-wheel drive type working vehicle as described above is configured as follows. That is, [1] a front wheel transmission that is switchable between a standard state in which the front wheels and the rear wheels are driven at substantially the same speed and an increased state in which the front wheels are driven at a higher speed than the rear wheels are transmitted to the front wheels. In addition to the system, a switching operation unit for switching the front-wheel transmission to a standard state and a speed-up state, and an operation member that is displaced by a steering operation of the front wheels over a set angle of right and left from a straight traveling position are provided. A first contact part is fixed to one of the switching operation part and the operation member, and a second contact part is provided to the other, so that when the operation member is displaced, the first contact part and the second contact part. With the department,
Even if the switching operation section is pushed from the standard state position to the acceleration state position and the operation member is displaced, the first contact portion and the second contact portion do not contact each other, and the switching operation is performed. The second part allows the swinging operation to the non-acting position where the part remains in the standard state position.
It supports the abutment.

[2] In the structure of [1] above, a gear shift lever for shifting the traveling transmission device and a lever guide for guiding the shift lever to the high speed side and the low speed side of the transmission device are provided. When the auxiliary lever guide is extended from the low speed position in a direction different from that of the lever guide, and the speed change lever is operated to the low speed position of the lever guide, the second contact portion is rocked to the non-acting position. And,
When the gear shift lever is operated into the auxiliary lever guide, the gear shift lever and the second abutment portion are moved so that the second abutment portion is swung to the operating position while the transmission is left at the low speed position of the lever guide. And are linked.

[0008]

[Action]

[I] When configured as in [1] above, for example, as shown in FIG.
As shown in (a), if the second contact portion 24 is rocked to the non-acting position, in this state, the steering operation of the front wheel at the right or left set angle or more causes Even if the operating member 12 is displaced as shown, the first contact portion 23a and the second contact portion 23a
The switching operation part 23 is not in contact with the contact part 24 and is left in the standard state position A (a state in which the front wheel transmission is left in the standard state without being switched to the speed increasing state during turning). .

Next, for example, as shown in FIG.
It is assumed that the contact portion 24 is rocked from the non-acting position to the acting position. In this state, when the operation member 12 is displaced and operated as described above, the first contact portion 23a and the second contact portion 24 contact each other as shown in FIG. Thus, the switching operation section 23 is pushed from the standard state position A to the speed increasing state position B. As a result, the front wheel transmission is switched from the standard state to the speed increasing state (a state in which the front wheel transmission is switched from the standard state to the speed increasing state during turning).

As described above, in the case of setting the two states, that is, the state in which the front wheel transmission is switched to the speed-increasing state and the state in which the front wheel transmission is not switched during turning, in the structure of the above [1], the second contact portion The above-mentioned two states can be set by the rocking operation. In this case, compared with the conventional structure in which the above-mentioned two states are set by sliding the cam member along the operation shaft by the spline structure, the second contact portion is pivotally operated around the support shaft. With this configuration, it becomes more difficult for an abnormality such as a twist phenomenon to occur.

[II] When configured as in the above item [2],
As in the case of the configuration of the above [1], the "action" described in the above [I] is provided, and in addition to this, the following "action" is provided. As described above, it is preferable that the front wheel transmission is switched to the speed-up state during turning when the traveling speed of the machine body is low. Therefore, with the configuration as in the above [2], for example, as shown in FIG. 8, when the speed change lever 33 of the transmission for traveling is operated to the low speed position L of the lever guide 34, FIG. As shown, the second contact portion 24 is rocked to the non-acting position, and a state is set in which the front wheel transmission is not switched to the speed-up state during turning. Next, if the speed change lever 33 is operated into the auxiliary lever guide 35 from the low speed position L, the second contact portion as shown in FIG. 24 is rocked to the operating position, and a state is set in which the front wheel transmission is switched to the speed increasing state during turning.

Therefore, with the construction of the above [2], after operating the speed change lever of the traveling speed change device to the low speed position, the speed change lever is directly operated inside the auxiliary lever guide without releasing the speed change lever. Thus, it is possible to set the state in which the front wheel transmission is switched to the speed-up state during turning. On the contrary, the gear shift lever is operated from the auxiliary lever guide to the low speed position (the front wheel transmission is not switched to the speed increasing state during turning), and the gear shift lever is directly moved along the lever guide to the high speed side for traveling. Can be operated. This makes it difficult to operate the shift lever to the low speed position and then operate another switching lever for the front wheel transmission to set a state in which the front wheel transmission is switched to the speed-up state during turning. You don't have to.

[0013]

According to the first aspect of the present invention, in a four-wheel drive type work vehicle equipped with a front wheel transmission, there are two states, that is, a state in which the front wheel transmission is switched to a speed-up state and a state in which the front wheel transmission is not switched during turning. The state can now be set to be less abnormal such as a twisting phenomenon and the reliability of the four-wheel drive work vehicle can be improved.

According to the second aspect, similar to the case of the first aspect, the above-mentioned "effect of the invention" is provided. According to the present invention, the gear shift lever of the traveling transmission can set two states, that is, a state in which the front wheel transmission is switched to the speed increasing state and a state in which the front wheel transmission is not switched during turning. It becomes a good one.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an engine 3 is provided in the front part of the machine body supported by a pair of left and right steerable front wheels 1 and a pair of left and right rear wheels 2, and a control section 4 is provided in the center part of the machine body. The link mechanism 5 is connected to the rear part so that it can be moved up and down, and the seedling planting device 6 is connected to the link mechanism 5 to form a four-wheel drive type rice transplanter, which is an example of a four-wheel drive work vehicle. There is.

Next, the transmission system for traveling will be described.
As shown in FIG. 1, the power from the engine 3 is transmitted to the hydrostatic continuously variable transmission 11 at the rear portion, and the continuously variable transmission 11
The power from the vehicle is branched in parallel, one of the branched power is transmitted to the seedling planting device 6, and the other power of the branched is transmitted via the gear transmission 8 (corresponding to a traveling transmission) to the rear wheels. 2 is transmitted. The power branched from immediately before the rear wheel 2 is transmitted to the front wheel transmission 14 connected to the front axle case 13 and transmitted to the left and right front wheels 1.

Next, the front wheel transmission 14 will be described. As shown in FIG. 2, the speed change shaft 16 is arranged in parallel above the pinion shaft 15 that drives the differential mechanism 7 in the front axle case 13, and the power branched immediately before the rear wheel 2 is applied to the speed change shaft 1
6 has been transmitted. A first standard gear 17 and a first speed increasing gear 18 are fitted onto the speed change shaft 16 so as to be rotatable relative to each other, and a second standard gear 19 and a second speed increasing gear 20 fixed to the pinion shaft 15 are The first standard gear 17 and the first speed increasing gear 18 are engaged with each other. The shift gear 2 is attached to the transmission shaft 16.
Reference numeral 1 denotes a spline structure, which is externally fitted to the transmission shaft 16 so as to rotate integrally and slidably.

With the above structure, when the shift gear 21 is slid to the left in the plane of the drawing to be engaged with the first standard gear 17, the front wheel 1 and the rear wheel 2 are driven at substantially the same speed, and the power is applied to the front wheel. 1 is transmitted. On the contrary, the shift gear 21
When the wheel is slid rightward on the paper surface and engaged with the first speed increasing gear 18, the power is transmitted to the front wheel 1 in a speed increasing state in which the front wheel 1 is driven at a higher speed than the rear wheel 2.

Next, the linkage between the pitman arm 22 for steering operation of the front wheels 1 and the front wheel transmission 14 will be described. As shown in FIGS. 3 and 2, the shift shaft 9 fixed to the shift fork 9a for slidingly operating the shift gear 21 of the front wheel transmission 14 is rotatably supported and extends outside the front wheel transmission 14. An operation arm 23 (corresponding to a switching operation unit) is fixed to the outer end of 9. Figure 5
As shown in (a) and FIG. 3, the pin 2 is attached to the operation arm 23.
3a (corresponding to the first contact portion) is fixed, and the side where the shift gear 21 meshes with the first standard gear 17 (standard state side)
The spring 10 for urging is connected to the pin 23 a of the operation arm 23.

A flat plate-shaped first operating member 12 (corresponding to an operating member) is swingably supported around the horizontal axis P2 on the outer surface of the front wheel transmission 14, and the first operating member 12 is rotated around the horizontal axis P3. A second operation member 24 (corresponding to a second contact portion) is swingably supported by the. A spring 29 for urging the second operating member 24 in the clockwise direction of the paper surface of FIG. 5A (on the non-acting position side described later) with respect to the first operating member 12 is provided with the first operating member 12 and the second operating member 12.
It is connected to the operation member 24.

As shown in FIGS. 3 and 4, the front axle case 1
On the front side of 3, the pitman arm 22 for steering operation of the front wheel 1 is supported swingably around the vertical axis P1, and the left and right front wheels 1 and the pitman arm 22 are linked via a tie rod 25. Has been done. An operation shaft 26 is vertically rotatably supported next to the pitman arm 22, and the first arm 2 fixed to the lower end of the operation shaft 26.
The roller 26c of 6a is abutted against the cam portion 22a of the pitman arm 22, and the second arm 26b fixed to the upper end of the operation shaft 26 is connected to the first operation member 12 via the linkage rod 27 and the spring 28 for accommodation. It is connected to the.

With the above structure, the steering handle 3 shown in FIG.
At 0, when the pitman arm 22 is rockingly operated from the straight ahead position to the right and left before the steering limit, the operation shaft 26, the first operation member 12 and the like are not operated, and the first operation is performed. The member 12 is in the posture shown in FIG.
The urging force of 0 holds the operating arm 23 in the standard state position A (the standard state in which the shift gear 21 of the front wheel transmission 14 of FIG. 2 is engaged with the first standard gear 17).

When the pitman arm 22 is rocked to the right or left steering limit from the above state, the cam portion 22a of the pitman arm 22 pushes the first arm 26a of the operation shaft 26 downward in the plane of FIG. Operated and operated axis 26
Rotates counterclockwise on the paper by a predetermined angle and the linkage rod 27
Is pushed to the left on the paper surface, and the operation shown in FIG.
As shown in (b), the first operating member 12 is rocked in the counterclockwise direction of the drawing (the first operating member 12 is displaced). In this case, as shown in FIG.
When the operation member 24 is swingingly operated in the non-acting posture, as shown in FIG.
As shown in (b), even if the first operating member 12 is rocked, the second operating member 24 cannot contact the pin 23a of the operating arm 23, and the operating arm 23 moves to the standard state position A. It is left.

Next, as shown in FIG.
The pulling operation causes the second operating member 24 to swing and hold the second operating member 24 in the acting position against the spring 29. From the above state, when the pitman arm 22 is rocked to the right or left steering limit, and the first operation member 12 is rocked counterclockwise in the same manner as described above, as shown in FIG. ), The second operating member 24 contacts the pin 23 a of the operating arm 23, and the second operating member 24 swings the operating arm 23 to the speed increasing state position B. As a result, the front wheel transmission 1 of FIG.
In 4, the shift gear 21 is slid rightward on the paper surface to be engaged with the first speed increasing gear 18, and power is transmitted to the front wheel 1 in a speed increasing state in which the front wheel 1 is driven at a higher speed than the rear wheel 2.

As described above, the front wheel transmission 1 of FIG.
When the shift gear 21 of No. 4 is slid to the first speed increasing gear 18 side, the shift gear 21 does not match the phase of each other.
Is unable to occlude the first speed increasing gear 18 well,
The spring 28 of the linking rod 27 of (a) and (b) is compressed, and the pushing operation of the linking rod 27 is absorbed. In this case, the spiral spring 28 is compressed to a state where the spring 28 is in close contact, and if the phases of the shift gear 21 and the first speed increasing gear 18 match, the biasing force of the spring 28 causes the shift gear 21 to move to the first speed increasing speed. It engages with the gear 18.

Next, the structure of the operating system for swinging the second operating member 24 to the non-acting position shown in FIG. 6A and the acting position shown in FIG. 5A will be described. As shown in FIGS. 7 (a) and 7 (b), the speed change shaft 32 for speed-changing the gear speed change device 8 is rotatably supported, and the speed change lever 33 is swingable around the axis P4 at the tip of the speed change shaft 32. It is supported. As a result, the transmission lever 32 is operated to the high speed position H, the neutral position N and the low speed position L along the lever guide 34 shown in FIG.
To shift gears between high and low.

An operation plate 36 is swingably supported around the horizontal axis P5 at the upper end of the arm 32a fixed to the speed change shaft 32. The operation plate 36 and the second operation member 24 of FIG.
Are connected via an arc-shaped link arm 37 and a wire 31, and the shift lever 33 and the operation plate 36 are connected via a link 38. 7 (a) and 8
As shown in, the auxiliary lever guide 35 extends from the low speed position L of the lever guide 34 in a direction orthogonal to the lever guide 34.

As shown in FIGS. 7A and 8, the low speed position L of the lever guide 34 is in the OFF position of the auxiliary lever guide 35, and the shift lever 33 is in the low speed position L.
When the switch 31 is operated (OFF position), the wire 31 is not pulled to the speed change lever 33 side, and the second operating member 24 is swingably operated to the non-acting position shown in FIG. As a result, even if the pitman arm 22 is swung to the right or left steering limit as shown in FIGS. 6A to 6B, the first operating member 12 swings counterclockwise in the drawing. However, the operating arm 23 remains in the standard state position A (the front wheel transmission 14 remains in the standard state and is not switched to the speed increasing state). Then, the shift lever 33
Along the lever guide 34 to the neutral position N and the high speed position H.
Even if it is operated to, the wire 31 is not pulled and the operation arm 23 is maintained in the standard state position A.

Next, when the shift lever 33 is operated from the low speed position L to the ON position in the auxiliary lever guide 35, the operation plate 36 is rocked to the left side of the paper as shown in FIG. Is pulled and the gear shift lever 33 is held at the ON position of the auxiliary lever guide 35 by the action of the linkage arm 37. In this way, when the wire 31 is pulled toward the speed change lever 33, the second operating member 24 is swingably operated and held at the operating position against the spring 29, as shown in FIG. Therefore, when the pitman arm 22 is rocked to the right or left steering limit as shown in FIG. 5 (a) to FIG. 5 (b) (first operation member 12
Is rotated counterclockwise on the paper surface), the operation arm 2
3 is pushed from the standard state position A to the speed increasing state position B (the state in which the front wheel transmission 14 is switched from the standard state to the speed increasing state).

[Other Embodiments] In the structure of FIGS. 5A and 6A, the second operating member 24 is swingably supported by the first operating member 12, but the second operating member 24 is Operation arm 2
3 may be configured to be swingably supported. Further, the present invention can be applied not only to the riding type rice transplanter but also to a four-wheel drive type agricultural tractor.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

[Fig. 1] Overall side view of the riding rice transplanter

FIG. 2 is a vertical sectional side view of a front wheel transmission device.

FIG. 3 is a side view showing a structure in which a pitman arm and an operation arm of a front wheel transmission are linked with each other.

FIG. 4 is a plan view near the pitman arm.

FIG. 5 is a side view showing a state before and after a swing operation of the first operating member in a state where the second operating member is operated to the operating position.

FIG. 6 is a side view showing a state before and after a swing operation of the first operating member in a state where the second operating member is operated to a non-acting position.

FIG. 7 is a rear view showing a state in which the shift lever is operated to a cut position and a shift position.

FIG. 8 is a plan view showing a lever guide and an auxiliary lever guide of a shift lever.

[Explanation of symbols]

 1 front wheel 2 rear wheel 8 speed change device for traveling 12 operation member 14 front wheel speed change device 23 switching operation part 23a first contact part 24 second contact part 33 speed change lever 34 lever guide 35 auxiliary lever guide A standard state position B increase High speed position L Low speed position

Claims (2)

[Claims] 1. A normal state in which a front wheel (1) and a rear wheel (2) are driven at substantially the same speed, and an increased state in which a front wheel (1) is driven at a higher speed than a rear wheel (2). A front wheel transmission (14) capable of switching operation is provided in a transmission system to the front wheel (1), and a switching operation section (23) for switching the front wheel transmission (14) between a standard state and a speed-up state. An operating member (12) that is displaced by steering operation of the front wheel (1) at a set angle of right and left from a straight ahead position is provided, and among the switching operating part (23) and the operating member (12) The first contact part (23a) is fixed to one side, and the second contact part (24) is provided to the other side. When the operation member (12) is displaced, the first contact part (23a) is moved. And the second contact part (24) contact each other, and the switching operation part (23) accelerates from the standard position (A). Even if the operating position is pushed to the position (B) and the operating member (12) is displaced, the first contact portion (2)
3a) and the second contact portion (24) are not in contact with each other, and the switching operation portion (23) is swingably operated to a non-acting position left in the standard state position (A) so that the second contact portion is movable. A four-wheel drive work vehicle supporting a part (24). 2. A shift lever (33) for shifting the traveling transmission (8) and a lever guide (34) for guiding the shift lever (33) to a high speed side and a low speed side of the transmission (8). ) And an auxiliary lever guide (35) is extended from the low speed position (L) of the lever guide (34) in a direction different from the lever guide (34), and the shift lever (33) is connected to the lever. When the guide (34) is operated to the low speed position (L), the second contact portion (2)
When the gear shift lever (33) is moved into the auxiliary lever guide (35) such that the gear shift lever (4) is swung to the non-acting position, the transmission (8) causes the gear shift lever (33) to move to the lever guide (3).
4) The gear shift lever (33) and the second contact portion (24) so that the second contact portion (24) is oscillated to the operating position while being left in the low speed position (L). The four-wheel drive work vehicle according to claim 1, wherein