JPH11334402A - Paddy farming work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly operate a turning auxiliary device to an operation side when a front wheel is steered right or left without any mud effect in a paddy farming work vehicle provided with a front wheel transmission and a turning auxiliary device such as a side brake, a side clutch or the like. SOLUTION: A steering transmission mechanism 34 for transmitting the steering operation of a steering handle to a pitman arm is disposed inside a supporting case 4, first linking means 35 and 37 for taking out the steering operation of the steering transmission mechanism 34 are disposed inside the supporting case 4, and the first linking means 35 and 37 are connected with a turning auxiliary mechanism via second linking means 41 and 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a traveling system of a paddy working vehicle such as a riding type rice transplanter, a riding type direct sowing machine, a riding type management machine and the like used in paddy fields.

[0002]

2. Description of the Related Art There is a riding type rice transplanter, which is an example of a paddy field working vehicle as described above, provided with a turning assist mechanism for smoothly turning in a paddy field. Sometimes a front wheel transmission that allows the front wheels to be driven at a higher speed than the rear wheels, a side brake that can independently brake the right and left rear wheels, and an independent transmission and transmission of power to the right and left rear wheels There is a side clutch capable of interrupting transmission.

For example, a riding type rice transplanter having a front wheel transmission as a turning assist mechanism is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-11897.
As disclosed in Japanese Unexamined Patent Application Publication No. 6-106, a pitman arm that steers the front wheels to the right and left (see FIGS.
In 22), the steering operation of the pitman arm is
It is taken out by a cam (22a in FIGS. 3 and 4 of the above-mentioned publication), and is taken out of a front wheel transmission (1 of FIGS. 2 and 3 of the above-mentioned publication).
There is one configured to transmit to 4). As a result, the front wheel transmission is operated in the standard state when traveling straight,
When the front wheel is driven at substantially the same speed as the rear wheel, and the pitman arm steers the front wheel to the right or left when turning on a ridge, etc., the steering operation of the pitman arm is transmitted to the front wheel transmission, The front wheel transmission is operated in the speed increasing state. In the speed-up state of the front wheel transmission, the front wheels are driven at a higher speed than the rear wheels, and the body turns smoothly by the pulling action of the front wheels in the turning direction.

[0004]

A paddy field working vehicle such as a riding rice transplanter travels in a state where the front and rear wheels are submerged to some extent in the paddy field, so that a lot of mud adheres to the lower part of the body. A lot of mud also adheres near the pitman arm. As a result, when mud adheres to the portion where the steering operation of the pitman arm is taken out, and the mud is bitten into the operating portion, etc., the mud interferes with the removal of the steering operation of the pitman arm, and It is conceivable that a state occurs in which the steering operation cannot be properly taken out. The present invention is directed to a paddy field vehicle equipped with a turning assist mechanism such as a front wheel transmission, a side brake, and a side clutch so that the turning assist mechanism is appropriately operated to the operating side when the front wheel is steered to the right or left. It is intended to be configured.

[0005]

According to a first aspect of the present invention, a steering transmission mechanism for transmitting a steering operation transmitted from a steering handle to a pitman arm for steering a front wheel to the right and left, First linking means, which is provided inside the support case and takes out the steering operation of the steering transmission mechanism, is disposed inside the support case, and the steering operation of the steering transmission mechanism is taken out by the first linkage means,
It is transmitted to the turning assist mechanism via the second linking means.
By arranging the first linking means for taking out the steering operation of the steering transmission mechanism inside the support case as in the feature of the first aspect, the paddy field vehicle can be operated in a state where the front wheel and the rear wheel are submerged to some extent in the paddy field. Even when the vehicle travels, the first linking means is protected by the support case, and a state in which mud adheres to the first linking means is avoided.

[II] According to the features of claim 2, similar to the case of claim 1, the "action" described in the above-mentioned [I] is provided, and in addition to this, the following "action" is provided. ing. The paddy field work vehicle may be configured to be able to select between a state in which the turning assist mechanism is operated during turning and a state in which the turning assist mechanism is not operated, depending on conditions such as the hardness of the mud in the paddy field and the depth of the paddy field.

According to the second aspect of the present invention, a linked state in which the steering operation of the steering transmission mechanism is taken out (a state in which the turning assist mechanism is operated during turning), and a linked state in which the steering operation of the steering transmission mechanism is not taken out (turning). Operating means capable of operating the first linking means in a state where the turning assist mechanism is not operated at times). In this case, since the first linking means is arranged inside the support case as described in [I] above, the operation means is also arranged inside the support case. Thus, the operating means is also protected by the support case in the same manner as the first linking means, and a state in which mud adheres to the operating means is avoided.

[III] According to the feature of claim 3, similar to the case of claim 2, the "action" described in the above [I] and [II] is provided, and in addition to this, the following "action" is provided. "
It has. When turning is performed by operating the turning assist mechanism to the operating side during turning, a small turning operation is often performed by the action of the turning assist mechanism. Operates the first linking means to the linked state and the unlinked state by the operating means,
In a state where the worker recognizes that the linking means is being operated in the linked state, the worker steers the front wheel to the right or left with the control handle, and the turning assist mechanism is operated to the operating side. Preferably, there is. This is a situation in which the operator operates the front wheel to the right or left with the control handle in a state where the first linking means is operated in the linked state and the worker misunderstands that the first linking means is operated in the unlinked state. This is because when the direction operation is performed, a situation occurs in which the turning assist mechanism is unexpectedly operated to the operating side for the operator.

According to a third aspect of the present invention, if the operating means is configured to be biased to the uncoupling state by the biasing means, the operating means (first linking means) is linked based on some operation or the like. Since the operation is automatically performed in the release state, the operator turns the first linkage means in the linkage state, but mistakes that the operator is operating in the linkage release state. The state where the turning assist mechanism is sometimes unexpectedly operated to the operating side can be reduced.

[IV] According to the feature of claim 4, as in any one of claims 1 to 3, the above [I]
To [III], in addition to the following “action”. According to the feature of claim 4, the first from the right or left side of the support case.
The linking means protrudes, and the protrusion of the first linking means and the turning assist mechanism are linked by the second linking means. Accordingly, when adjusting the linking portion between the projecting portion of the first linking means and the second linking means, the adjustment can be performed only on one of the right and left sides of the support case, and the right and left sides of the support case can be adjusted. In both of the parts, it is not necessary to adjust the link between the projecting portion of the first linking means and the second linking means.

[V] According to the feature of claim 5, claim 1 is
As in any one of the above [I] to [4],
It has the “action” described in [IV], and additionally has the following “action”. When the first linking means projects from one of the right and left sides of the support case, and the projecting portion of the first linking means and the turning assist mechanism are linked by the second linking means, as in the feature of claim 4, A wire is often used as the second linking means.

According to a fifth aspect of the present invention, when the first linking means projects from one of the right and left sides of the support case,
A pair of wires as the second linking means are arranged in the same direction along the operation direction of the protrusion of the first linking means, and the inner of one wire and the outer of the other wire are connected to the protrusion of the first linking means. Connected. Thus, when the protrusion of the first linking means moves to one side, the inner of one wire is pulled, and when the protrusion of the first linking means moves in the opposite direction, the outer of the other wire moves in the opposite direction. As a result, the inner side of the other wire is pulled.
According to the fifth aspect of the present invention, when the first linking means is projected from one of the right and left sides of the support case, the pair of wires are arranged in the same direction not obstructed by the support case, and the first linking means is provided. The inner portion of the pair of wires can be pulled and operated by the operation of the projecting portion of the means.

[VI] According to the feature of claim 6, as in any one of claims 1 to 5, the above [I]
To [V], in addition to the following “action”. In a paddy field working vehicle having a ground working device supported on an airframe, when the front wheel is steered to the right or left to start turning, the ground working device located on the rice field needs to be raised to perform turning. According to the feature of claim 6, when the pitman arm is steered through the steering transmission mechanism to start turning, the ground working device is automatically raised, so that the work is performed when the turning is started. It is not necessary for the user to raise the ground working device by an artificial operation using the operation lever or the like.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an engine 3 and a transmission case are provided at the front of a body supported by a pair of left and right front wheels 1 and a pair of left and right rear wheels 2 that can be steered right and left. 4, a control unit 7 including a control handle 5 and a control seat 6 is disposed in the center of the fuselage, and a seedling planting device 9 is supported by a link mechanism 8 provided at the rear of the fuselage. Further, a hydraulic cylinder 10 for operating the link mechanism 8 up and down is provided.

The power of the engine 3 is transmitted to the transmission case 4, and the transmission is operated by a transmission (not shown) provided in the transmission case 4 to change the speed of the front axle case 11.
(Refer to FIG. 2) and transmitted to the right and left front wheels 1 via a front wheel differential mechanism (not shown). The power branched from the transmission system to the right and left front wheels 1 is transmitted via the transmission case 4, the transmission shaft 12, and the rear axle case 13 to the right and left rear wheels 2.
Is transmitted to

Next, the rear axle case 13 will be described. As shown in FIG. 11, one first axle is attached to the rear axle case 13.
The transmission shaft 14 is arranged, and the power of the transmission shaft 12 from the transmission case 4 is transmitted to the first transmission shaft 14 via a pair of bevel gears 12a and 14a. A pair of second transmission shafts 15 are arranged concentrically on the left and right of the first transmission shaft 14, and the power transmitted to the second transmission shaft 15 is transmitted by the transmission gear 1.
6, the power is transmitted to a rear axle 17 supporting the rear wheel 2.

As shown in FIGS. 12 and 11, at a portion where the first transmission shaft 14 and the right and left second transmission shafts 15 are arranged concentrically, a ring-shaped first support member 18 is provided. The first transmission shaft 14 is integrally rotatably and slidably fitted to the outside of the first transmission shaft 14 in a spline structure, and a cylindrical second support member 19 is fixed to an end of the second transmission shaft 15. A number of friction plates 20 are arranged between 18, 19,
A side clutch 21 is formed between the first and second support members 18 and 19. The stopper rings 18a and 19a are provided between the first and second support members 1 so as to sandwich the friction plate 20.
A spring 22, which is attached to the first and second transmission shafts 14 and 19, biases the first support member 18 to the right in FIG. 12.

As described above, the first support member 1 is
12 is urged to the right in FIG. 12, the friction plates 20 are pressed by the stopper rings 18a and 19a, and the side clutch 21 is in a transmission state, and the power of the first transmission shaft 14 is transmitted to the side clutch 21. The right and left rear wheels 2 are transmitted to the right and left second transmission shafts 15 via the right and left wheels. As shown in FIGS. 12 and 11, a first cylindrical operating member 23 is slidably fitted to the first transmission shaft 14, and the first operating member 23 is slid to the left in FIG. When the first support member 18 is pushed to the left in FIG. 12, the pressing of the friction plate 20 by the stopper rings 18a and 19a disappears, and the transmission of the side clutch 21 is interrupted. By operating one of the side clutches 21 in the transmission cutoff state, the power of the first transmission shaft 14 is not transmitted to the one second transmission shaft 15 and the one rear wheel 2 can be freely rotated. In the free state, the first transmission shaft 1
4 can be transmitted to the other second transmission shaft 15 to drive the other rear wheel 2.

As shown in FIGS. 12 and 11, a plurality of friction plates 24 are provided between the second support member 19 and the rear axle case 13.
Is disposed, the second support member 19 and the rear axle case 13
A side brake 25 is formed between the two. A cylindrical second operation member 27 is externally fitted to the first support member 18 via a bearing 26, and the first support member 18 and the second operation member 27 are integrally slidable.

As described above, when the first support member 18 is urged to the right in FIG. 12 by the spring 22 and the side clutch 21 is operated in the transmission state, the second operation member 27 is actuated.
Is separated from the friction plate 24, and the side brake 25 is operated in the brake release state. When the second operation member 27 is slid leftward on the paper from the state shown in FIG. 12, the first support member 18 is separated from the first operation member 23, and the side clutch 21 is operated in the transmission cutoff state. (2) The operation member 27 presses the friction plate 24, and the side brake 25
Is operated in the braking state, and the second transmission shaft 15 (rear wheel 2) is braked.

Next, the structure of the steering operation of the front wheel 1 will be described. As shown in FIGS.
A steering shaft 28 is rotatably supported vertically at a front portion of the front axle case 11, and a pitman arm 29 is fixed to a portion of the steering shaft 28 projecting downward from a lower portion of the transmission case 4. A tie rod 30 is connected across the front wheel 1 and the pit moom 29 which are supported to be steerable. As shown in FIGS. 3, 4, and 6, a large-diameter first
A gear 32a and a small-diameter second gear 32b are supported so as to rotate integrally, and an operation shaft 31 interlocked with the steering handle 5 shown in FIG. 1 is connected to a pinion gear 33 that meshes with the first gear 32a. Have been. Steering shaft 2
A fan-shaped operation gear 34 is fixed to the upper part of the gear 8, and the operation gear 34 is engaged with the second gear 32b. By operating the steering handle 5 with the above structure, the pitman arm 29 is steered by the pinion gear 33, the first and second gears 32a and 32b, the operation gear 34, and the steering shaft 28, and the front wheel 1 is moved to the right. And the steering operation is performed to the left.

Next, the linking between the right and left steering operations of the front wheel 1 and the side clutch 21 shown in FIG. 12 will be described. As shown in FIGS. 4, 6, 7 and 9, inside the transmission case 4, a diamond-shaped engaging member 36 is supported on the upper end of the steering shaft 28 so as to be vertically slidable. The bent portion 36a is inserted into the long hole 34a of the operation gear 34. In this case, the engagement member 36
The bent portion 36a and the elongated hole 34a of the operation gear 34 have the same width, so that the engagement member 36 rotates integrally with the operation gear 34 and the steering shaft 28 while rotating the steering shaft 28.
Is slid up and down.

A link rod 35 is slidably supported in the left-right direction of the transmission case 4, and an end of the connection rod 35 projects laterally from a right side of the transmission case 4. On the lower side of the operation gear 34, a linking member 37 is fitted around the steering shaft 28 so as to be relatively rotatable, and a long hole 35b of a bracket 35a fixed to the linking rod 35 is provided.
, The pin 37a of the linking member 37 is inserted. A long hole 37b wider than the bent portion 36a of the engaging member 36
Are formed on the linking member 37, and the state shown in FIGS.
6 is pushed downward, and the bent portion 3 of the engaging member 36 is pressed.
6a is in a state where it has entered the long hole 37b of the linking member 37.

As shown in FIGS. 6 and 8, in the link rod 35 projecting laterally from the right side of the transmission case 4, the support plate 3 is positioned above the link rod 35.
9 is fixed to the transmission case 4. Support plate 39
The outer 41b of the wire 41 is fixed to the end of the wire 41, and the inner 41a of the wire 41 is inserted into an opening (not shown) of the bracket 40 attached to the link rod 35, and the end of the inner 41a of the wire 41 is inserted. Is provided with a retaining member 41c. The outer 42 b of the wire 42 is fixed to the bracket 40, and the inner 42 a of the wire 42 is inserted into an opening (not shown) of the base 39 a of the support plate 39, and a retaining member is provided at the end of the inner 42 a of the wire 42. 42c is attached.

As shown in FIGS. 2 and 11, a pair of left and right operation shafts 43 are rotatably supported by the rear axle case 13. As shown in FIGS. The cored pin 43a is inserted into the hole 23a of the first operation member 23 of the right and left side clutches 21. Arm 43b fixed to right and left operation shafts 43
2 and 10 are directed to the left and right center sides as shown in FIGS. 2 and 10, and the inner 41a of the wire 41 is connected to the arm 43b of the right operating shaft 43 as shown in FIGS. Is connected to the arm 43b of the left operating shaft 43. In this way, along the sliding direction of the link rod 35, the wires 41,
42 are arranged (see FIG. 6).

The state shown in FIGS. 2 and 6 is a state in which the front wheel 1 is operated to the straight traveling position by the steering handle 5,
As shown in FIG. 12, the right and left side clutches 21 are operated in the transmission state, and the power is transmitted to the right and left front wheels 1 and the right and left rear wheels 2. In this state, even if the front wheel 1 is steered to the right or left by the steering handle 5 and the engagement member 36 rotates integrally with the operation gear 34 and the steering shaft 28, the bent portion 36a of the engagement member 36 is If only the range of the long hole 37b of the linking member 37 is moved, the linking member 37 and the linking rod 35 maintain the state shown in FIG. 6, and the right and left front wheels 1 and the right and left rear wheels 2 Is maintained.

Next, when the front wheel 1 is steered to the left by the steering handle 5 from the state shown in FIGS.
When the front wheel 1 is further steered leftward after the bent portion 36a of the sixth member reaches the end of the long hole 37b of the link member 37, the bent portion 36a of the engagement member 36 and the long hole 37b of the link member 37 6, the linking member 37 rotates in the counterclockwise direction in FIG. 6 together with the operation gear 34 and the steering shaft 28, and the linking rod 35 is moved out of the transmission case 4 to the outside (the lower side in FIG. 6). ) Is done.

As described above, when the link rod 35 is pulled out of the transmission case 4 and operated, the outer rod 42b of the wire 42 is separated from the retaining member 42c by the link rod 35 as shown in FIG. 2 and 10, the left operating shaft 43 shown in FIGS. 2 and 10 is rotated, and the pin 43a of the left operating shaft 43 is used to rotate the left first operating member 2.
3 is slid to the left in FIG. 12, and the left side clutch 21 starts operating from the transmission state to the transmission cutoff state.

Thus, when the front wheel 1 is steered from the straight-ahead position to the left steering limit, the engagement member 3 is moved from the straight-ahead position to the steering member.
Until the sixth bent portion 36a reaches the end of the long hole 37b of the link member 37, the state in which power is transmitted to the right and left front wheels 1 and the right and left rear wheels 2 is maintained. When the front wheel 1 is further steered to the left, the left side clutch 21 starts to be operated from the transmission state to the transmission cutoff state, and the power transmitted to the left rear wheel 2 gradually decreases.
When the front wheel 1 is steered to the left steering limit, the left side clutch 21 is completely in the power transmission cutoff state, and is in a free state in which the left rear wheel 2 can rotate freely. In contrast,
The same power is transmitted to the right and left front wheels 1 and the right rear wheel 2.

Next, when the front wheel 1 is steered to the right by the steering handle 5 from the state shown in FIGS.
When the front wheel 1 is further steered to the right after the bent portion 36a of the sixth member 6 reaches the end of the long hole 37b of the link member 37, the bent portion 36a of the engaging member 36 and the long hole 37b of the link member 37 are moved. 6, the linking member 37 rotates clockwise in FIG. 6 along with the operating gear 34 and the steering shaft 28, and the linking rod 35 is pulled into the transmission case 4 (upper side in FIG. 6). Is done. As described above, when the link rod 35 is pulled into the transmission case 4, the inner rod 41a of the wire 41 is pulled by the link rod 35 as shown in FIG. Of the right operating shaft 43 is rotated by the pin 43a of the right operating shaft 43.
Is operated to slide, and the right side clutch 21 starts to be operated from the transmission state to the transmission cutoff state.

Thus, when the front wheel 1 is steered from the straight traveling position to the right steering limit, the engaging member 3 is moved from the straight traveling position to the right steering limit.
Until the sixth bent portion 36a reaches the end of the long hole 37b of the link member 37, the state in which power is transmitted to the right and left front wheels 1 and the right and left rear wheels 2 is maintained. When the front wheel 1 is further steered to the right, the right side clutch 21 starts to be operated from the transmission state to the transmission cutoff state, and the power transmitted to the right rear wheel 2 gradually decreases.
When the front wheel 1 is steered to the right steering limit, the right side clutch 21 is in a completely transmission cutoff state, and is in a free state in which the right rear wheel 2 can freely rotate. In contrast,
The same power is transmitted to the right and left front wheels 1 and the left rear wheel 2.

As shown in FIGS. 6 and 8, by rotating the screw type adjusting portion 44, the fixing position of the outer 41 b of the wire 41 with respect to the support plate 39 and the fixing position of the outer 42 b of the wire 42 with respect to the bracket 40. Can be changed along the wires 41 and 42.
When the fixing position is changed in this way, the inner holes 41a and 42a of the wires 41 and 42 inserted into the opening of the bracket 40 and the opening of the base 39a of the support plate 39 also move together, and FIG. As shown, the retaining member 41
c, 42c are the base 3 of the bracket 40 and the support plate 39.
The retaining members 41c and 42c can be slightly separated from the bracket 40 and the base 39a of the support plate 39 upward from the state of being in contact with 9a. As a result, when the link rod 35 is extended and pulled out as described above, the inner members 41a, 42 of the wires 41, 42 are formed.
It is possible to slightly delay the timing at which a is pulled and slightly delay the timing at which the right or left side clutch 21 starts operating from the transmission state to the transmission cutoff state.

Next, a configuration will be described in which the right and left side clutches 21 are not operated from the transmission state to the transmission cutoff state even when the front wheel 1 is steered right and left. As shown in FIGS. 3, 4, and 7, an operation rod 38 is rotatably supported along the left and right direction of the transmission case 4 above the engagement member 36 inside the transmission case 4. The operation arm 38 a is fixed, and the end of the operation rod 38 projects laterally from the right side of the transmission case 4. An operation plate 45 formed by bending a plate material is swingably supported around the horizontal axis P1 outside the transmission case 4.
An operation lever 46 is attached to the operation lever 5, and a toggle spring 47 is connected between the arm 38 b at the end of the operation rod 38 and the operation plate 45.

As shown in FIGS.
A spring 48 is provided which lifts the engaging member 36 and urges the bent portion 36a of the engaging member 36 in the direction of pulling out the long hole 37b of the linking member 37. The states shown in FIGS. 3, 4, and 7 are states in which the operating lever 46 is pressed down to operate the entering position, and the operating rod 38 is rotated counterclockwise in FIG. The engaging member 36 is pushed downward against the bent portion, and the bent portion 36 a of the engaging member 36
b. In this case, since the holding action by the toggle function of the toggle spring 47 is set to be stronger than the urging force of the spring 48, the bent portion 36a of the engagement member 36 is
The state of having entered is maintained. In this state, when the front wheel 1 is steered right or left, the right or left side clutch 21 is operated from the transmission state to the transmission cutoff state as described above.

Next, as shown in FIGS. 3 to 5, when the operating lever 46 is pulled up and operated to the cutting position, the operating rod 38 is rotated clockwise in FIG. 5 and the operating arm 38a is engaged. The bent portion 36 a of the engaging member 36 escapes upward from the elongated hole 37 b of the linking member 37 by the urging force of the spring 48. In this case, the state in which the bent portion 36a of the engagement member 36 is pulled upward from the long hole 37b of the linking member 37 is maintained by the spring 48, and the operation of the operation lever 46 and the holding lever 46 by the toggle function of the toggle spring 47 is maintained. The operating rod 38 is maintained in the cutting position. In this state, even if the front wheel 1 is steered to the right or left, only the engaging member 36 idles with respect to the linking member 37, and the linking rod 35 is not pulled out or pulled, and the right and left wheels are not moved. The side clutch 21 is not operated from the transmission state to the transmission cutoff state.

From the state where the operation lever 46 is operated to the cut position as shown in FIG. 5, the operation lever 4 is moved as shown in FIG.
6, when the front wheel 1 is steered right or left, the position of the bent portion 36a of the engaging member 36 and the position of the long hole 37b of the linking member 37 are shifted. Operation state, the operation arm 38
a, the engaging member 36 is pushed downward,
6 cannot be inserted into the elongated hole 37b of the linking member 37.

In this case, by the toggle function of the toggle spring 47 shown in FIG. 4, the operation lever 46 and the operation plate 45 are maintained at the entering position, and at the same time, the operation rod 38 is moved to the position shown in FIG.
The paper is urged in a counterclockwise direction. Accordingly, when the front wheel 1 is returned to the vicinity of the straight traveling position, the position of the bent portion 36a of the engaging member 36 matches the position of the long hole 37b of the linking member 37, so that the operation rod 38 is turned by the toggle function of the toggle spring 47. 4, the engaging member 36 is pushed downward against the spring 48 by the operating arm 38a, and the bent portion 36a of the engaging member 36 is inserted into the long hole 37b of the linking member 37. Get in.

In this riding type rice transplanter, when the front wheel 1 is steered to the right or left and the right or left side clutch 21 is operated from the transmission state to the transmission cutoff state as described above, At the same time, an automatic ascent function is provided for automatically raising the seedling planting device 9 from the rice field, and this automatic ascending function will now be described. As shown in FIGS. 6 and 8, a contact member 49 having a plate material bent in a trapezoidal shape is fixed to the link rod 35, and a limit switch 50 that contacts the contact member 49 is fixed to the support plate 39. , A signal from the limit switch 50 is input to a control device (not shown).

The state shown in FIGS. 6 and 8 is a state in which the front wheel 1 is being operated to the straight traveling position. In this state, the limit switch 50 comes into contact with the contact member 49 and the signal from the limit switch 50 automatically turns on. The lift function does not work. Next, when the front wheel 1 is steered to the right or left and the link rod 35 is pulled or pulled out, the contact member 49 moves together with the link rod 35, and the contact member 49 is moved to the limit switch. Move away from 50. In such a state, based on the signal of the limit switch 50, the control valve (not shown) of the hydraulic cylinder 10 shown in FIG. Thereby, the seedling planting device 9 is automatically raised from the rice field.

An operation switch (not shown) for operating the above-described automatic ascent function between an operating state and a stopped state is provided. If the operating switch is operated to the operating position, the front wheel 1 is moved to the right as described above. Or, when the steering operation is performed to the left, the seedling planting device 9 is automatically raised from the rice field. If the operation switch is operated to the stop position, the front wheel 1 is moved to the right or left as described above. , The seedling planting device 9 is not raised.

As shown in FIGS.
A limit switch 55 for detecting that the operation plate 6 and the operation plate 45 are operated to the entry position is fixed to the transmission case 4, and a signal of the limit switch 55 is input to the control device. Thereby, in the state where the operation lever 46 is operated to the ON position, the automatic ascent function can be operated to the operation state and the stop state by the operation switch described above. When the operation lever 46 is operated to the OFF position, The automatic ascent function is set to the stop state regardless of the operation switch.

Next, the operation structure of the side brake 25 will be described. As shown in FIGS. 12 and 11, a bifurcated operation arm 51 for pushing the rear end of the second operation member 27 of the side brake 25 is rotatably supported by the rear axle case 13 as a pair of left and right sides. 2 and FIG. 10, the operation shaft 51a of the operation arm 51 is connected to the rear axle case 13.
Arm 5 protruding outside of the arm and fixed to the operation shaft 51a.
1b is set so as to face the same machine right side. As shown in FIG. 2, a pair of side brake pedals 52 and 53 are disposed on the right front side of the control unit 7, and the right side brake pedal 52 and the arm 5 of the right side brake 25 are arranged.
1b is connected by a link rod 54, and the left side brake pedal 53 and the arm 5 of the left side brake 25
1b is connected by a link rod 54.

With the above structure, when the left side brake pedal 53 is depressed, the link rod 54 is pulled, and the operation arm 51 of the left side brake 25 is rotated counterclockwise in FIG. , Operation arm 5
12, the second operating member 27 is slid to the left in FIG. 12, the first support member 18 is separated from the first operating member 23, and the left side clutch 21 is changed from the transmission state to the transmission cutoff state as described above. The second operation member 27 presses the friction plate 24, and the left side brake 2
5 is operated in a braking state, and braking is applied to the left second transmission shaft 15 (the left rear wheel 2). Next, when the right side brake pedal 53 is depressed, the link rod 54 is pulled, and the right side clutch 21 is operated from the transmission state to the transmission cutoff state as described above, and the right side brake 25 is in the braking state. , The braking is applied to the right second transmission shaft 15 (the right rear wheel 2).

When the right and left side brake pedals 52 and 53 are depressed as described above, the first support member 18 is pushed by the slide operation of the second operation member 27 as shown in FIG. 18a, 19a
The pressing of the friction plate 20 by the
Is operated from the transmission state to the transmission cutoff state, and then the friction plate 24 is pressed by the sliding operation of the second operation member 27 to operate the side brake 25 in the braking state. As a result, the second operation member 2 of the side brake 25 becomes larger than the sliding operation amount of the first support member 18 of the side clutch 21.
The slide operation amount of No. 7 is larger.

[First Embodiment of the Invention] FIGS. 1 to 13
In the configuration shown in FIG. 2, when the front wheel 1 is steered to the right or left steering limit, the right or left side clutch 21 is operated to be in a complete transmission cutoff state. When the vehicle is steered to the right or left steering limit, the right or left side clutch 21 may be operated in a semi-transmission state in which power is transmitted to some extent.

1 to 13, the first operating member 23 and the operating shaft 43 are eliminated, and the wires 41 and 42 are replaced with the right and left side brakes 2 in FIGS.
5 may be connected to the arm 51b. Thus, when the front wheel 1 is steered to the right or left, the right or left side clutch 21 is changed from the transmission state to the transmission cutoff state, similarly to the case where the right or left side brake pedal 52, 53 is depressed. And the right or left side brake 25 is operated in the braking state.

[Second Alternative Embodiment of the Invention] FIGS. 1 to 13
11, the side clutch 21 is eliminated and the side brake 25 is left.
a, 14a is provided with a rear wheel differential mechanism (not shown),
2 and 10, the wires 41 and 42 may be connected to the arms 51b of the right and left side brakes 25. Thus, for example, when the front wheel 1 is steered from the straight-ahead position to the right steering limit, the right-hand operation is performed until the bent portion 36a of the engagement member 36 reaches the end of the long hole 37b of the link member 37 from the straight-ahead position. Also, power is transmitted to the left front wheel 1 and the right and left rear wheels 2, and the right side brake 25 is not operated in the braking state. Further, when the front wheel 1 is steered to the right, the right side brake 25 starts to be braked, and the braking is gradually applied to the right rear wheel 2, so that the front wheel 1 is steered to the right steering limit. When operated, the braking force of the right side brake becomes maximum. In this case, the braking force of the side brake 25 when the front wheel 1 is steered to the right and left steering limits is set to a strong braking force such that the right and left rear wheels 2 are completely stopped. Alternatively, the braking force may be set to a small value such that the right and left rear wheels 2 rotate to some extent with the turn.

Third Embodiment of the Invention The front wheel 1 and the rear wheel 2 are operated in a standard state in which they are driven at substantially the same speed, and the front wheel 1 is operated in a speed-up state in which it is driven at a higher speed than the rear wheel 2. A flexible front wheel transmission (not shown) is configured as shown in FIGS.
In preparation for the first alternative embodiment of the invention and the second alternative embodiment of the invention, the wires 41 and 42 may be connected to the front wheel transmission. As a result, when the front wheel 1 is steered to the right or left, and the right or left side clutch 21 starts operating from the transmission state to the transmission cutoff state (the right or left side brake 25 starts operating to the braking state). And) the front wheel transmission is operated from the standard state to the speed increasing state.

[0049]

According to the first aspect of the present invention, in a paddy field working vehicle equipped with a turning assist mechanism such as a front wheel transmission, a side brake, and a side clutch, a first linking means for extracting a steering operation of a steering transmission mechanism is supported. By arranging it inside the case and avoiding adhesion of mud to the first linking means, it is possible to prevent operation failure due to adhesion of mud and biting, so that operation of the steering transmission mechanism can be prevented. Direction operation can be properly taken out, and the operation reliability of the paddy field working vehicle can be improved.

According to the feature of claim 2, the "effect of the invention" of the above-mentioned claim 1 is provided similarly to the case of the claim 1, and in addition to the "effect of the invention", the following "invention" is provided. Of the effect. According to the second aspect of the present invention, the linking state in which the steering operation of the steering transmission mechanism is taken out (the state in which the turning assist mechanism is operated at the time of turning), and the linking state in which the steering operation of the steering transmission mechanism is not taken out (the turning assisting state in the turn). When the first linking device is provided with an operating device that can operate the first linking device in a state where the mechanism is not operated), like the first linking device, the operating device also avoids adhesion of mud,
By ensuring the operation of the operating means, the reliability of the operation of the paddy field working vehicle could be further improved.

According to the feature of the third aspect, similar to the case of the second aspect, the above-mentioned "effect of the invention" of the second aspect is provided, and in addition to the "effect of the invention", the following "invention" is provided. Of the effect. According to a third aspect of the present invention, if the operating means is configured to be biased to the disengaged state by the biasing means, the operating means (first
(Linking means) is automatically operated in the unlinked state, so that the operator mistakenly thinks that the operator is operated in the unlinked state while the first linking means is operated in the linked state. In this state, the state in which the turning assist mechanism is unexpectedly operated to the operating side during turning can be reduced, so that it is possible to prevent a decrease in ride comfort due to an operator's misunderstanding.

According to the feature of claim 4, the "effects of the invention" of the claims 1 to 3 are provided similarly to any one of the claims 1 to 3, and the "effects of the invention" are included in the "effects of the invention". In addition, it has the following "effects of the invention". According to the fourth aspect of the present invention, by projecting the first linking means from one of the right and left sides of the support case, adjustment of the linking portion between the projecting portion of the first linking means and the second linking means is performed. If
The operation can be performed only on one of the right and left sides of the support case, and the workability can be improved.

According to the feature of claim 5, the "effect of the invention" of the above-mentioned claim 4 is provided similarly to the case of the claim 4, and in addition to the "effect of the invention", the following "invention" is provided. Of the effect. According to the feature of the fifth aspect, when a wire is used as the second linking means, the pair of projections of the first linking means protruding from one of the right and left sides of the support case do not interfere with the support case, so that the pair of the support cases can be used. As a result, the turning assist mechanism can be operated to the operating side without any trouble by pulling the inner wire of the wire, and the operation reliability of the paddy field working vehicle can be further improved.

According to the feature of claim 6, as in any one of claims 1 to 5, the "effect of the invention" of the claims 1 to 5 is provided, and the "effect of the invention" is included in the "effect of the invention". In addition, it has the following "effects of the invention". According to the feature of claim 6, when the pitman arm is steered through the steering transmission mechanism to start turning, the ground working device is automatically raised, so that the work is performed when the turning is started. This eliminates the need for the user to raise the ground work device by an artificial operation using the operation lever or the like, and the operability of the paddy field work vehicle can be improved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a riding rice transplanter.

FIG. 2 is a schematic plan view showing the linked state of a steering wheel, right and left side brake pedals, right and left side clutches, and right and left side brakes.

FIG. 3 is a side view of the vicinity of a pitman arm in a transmission case.

FIG. 4 is a longitudinal sectional side view showing a state in which an operation lever is operated to an entering position near an operation gear of a transmission case.

FIG. 5 is a longitudinal sectional side view showing a state where an operation lever is operated to a cut position near an operation gear of a transmission case.

FIG. 6 is a cross-sectional plan view of the vicinity of an operation gear and a link rod in a transmission case.

FIG. 7 is a vertical sectional front view of the vicinity of an operation gear in a transmission case.

FIG. 8 is a front view of the vicinity of a link rod protruding from a transmission case.

FIG. 9 is an exploded perspective view showing an operation gear, a linking member, and an engaging member disposed inside a transmission case.

FIG. 10 is a plan view of a rear axle case.

FIG. 11 is a cross-sectional plan view of the rear axle case.

FIG. 12 is a cross-sectional plan view of the vicinity of a side clutch and a side brake in a rear axle case.

FIG. 13 is a vertical side view of the vicinity of an operation shaft of a side clutch in a rear axle case.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front wheel 4 Support case 5 Steering handle 9 Ground work device 21, 25 Turning assistance mechanism 29 Pitman arm 34 Steering transmission mechanism 35, 37 First linking means 36 Operating means 41, 42 Second linking means, wires 41a, 42a Inner wire 42b outer wire 48 biasing means

Claims (6)

[Claims] 1. A turning assist mechanism for assisting turning of an airframe, wherein a steering operation transmitted from an artificially operated steering handle is transmitted to a pitman arm that steers the front wheels right and left. A steering transmission mechanism; and a support case that houses the steering transmission mechanism. A first linking unit that takes out a steering operation of the steering transmission mechanism is disposed inside the support case, and the first linkage unit and the turning operation are performed. A second linking means for linking with the assist mechanism, wherein the first and the second and the third and the fourth steering mechanism are operated such that when the pitman arm is steered through the steering transmission mechanism, the turning assist mechanism is operated to the operating side. A paddy field work vehicle constituting a second linking means. 2. An operating means operable to operate the first linking means in a linked state in which the steering operation of the steering transmission mechanism is taken out and in a linked state in which the steering operation of the steering transmission mechanism is not taken out. The paddy field working vehicle according to claim 1. 3. The paddy field working vehicle according to claim 2, further comprising an urging means for urging the operation means to a disengaged state. 4. The first linking means is projected from one of a right side and a left side of the support case, and the projecting portion of the first linking means and the turning assist mechanism are linked by the second linking means. The paddy field working vehicle according to any one of claims 1 to 3. 5. The second linking means is constituted by a pair of wires arranged in the same direction along the operation direction of the projection of the first linking means, wherein the inner wire of the one wire and the outer wire of the other wire. 5. The paddy field working vehicle according to claim 4, wherein an inner wire of the one wire and an inner wire of the other wire are connected to the turning assist mechanism. 6. A lifting operation means for supporting the ground working device on the body so as to be able to lift and lower freely, and raising the ground working device when the pitman arm is steered through the steering transmission mechanism. The paddy field working vehicle according to any one of claims 1 to 5, wherein: