JP2001178206A - Four-wheel drive tractor for agriculture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agricultural four-wheel drive tractor to whose rear body portion a ground working machine is liftably connected and which has improved turning operability at the edge of a ride and enables an arbitrary operation for lifting or lowering the ground working machine by a worker. SOLUTION: This four wheel drive tractor for agriculture, provided with an operation means for automatically upward operating an actuator 57 for a ground working machine 56, when a front wheel speed-changing device is switched from a standard state into an accelerated state and when a side brake on the inside of the turning is switched into a weak braked state with a power steering mechanism, and capable of arbitrarily lifting or lowering the ground working machine 56 by the operation of a lifting lever 61 or a lifting switch 62.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheel drive agricultural tractor in which a ground working device such as a rotary tilling device is connected to the rear part of an airframe so as to be able to move up and down freely.

[0002]

2. Description of the Related Art In a farm tractor as described above, when a rotary tilling device (corresponding to a ground work device) is connected to the rear of the body to perform tilling work in a field, when the body reaches a ridge, a lifting lever is used. And other operations, such as operating the rotary tilling device upward, operating the steering handle, turning the aircraft 180 °, operating the lifting lever, etc., and lowering the rotary tilling device again to perform the tilling operation. ing. A front wheel transmission is provided which can be switched between a standard state in which the front wheels and the rear wheels are driven at substantially the same speed, and a speed-up state in which the front wheels are driven at a higher speed than the rear wheels. When the steering operation is performed at a set angle or more, the front wheel transmission is configured to be switched from the standard state to the speed increasing state,
There is an agricultural tractor configured so that a small turning can be smoothly performed near a ridge by a speed increasing action of a front wheel.

[0003]

In the above-described agricultural tractor, when the aircraft reaches a ridge while working in a field, the operator performs an ascending operation of the ground work device by using an elevating lever or the like, and the operator controls the aircraft by using a steering handle. Since two operations must be performed, such as performing a turning operation, there is room for improvement in operability. An object of the present invention is to improve the operability at the time of turning by effectively utilizing the front wheel transmission when the agricultural tractor is equipped with the front wheel transmission.

[0004]

The feature of the present invention resides in the following configuration of the four-wheel drive agricultural tractor as described above. That is, a front wheel transmission capable of freely switching between a standard state in which the front wheels and the rear wheels are driven at substantially the same speed, and a speed-up state in which the front wheels are driven at a higher speed than the rear wheels, and the front wheel being moved to the right or left A power steering mechanism for steering operation, a side brake capable of independently braking the left and right rear wheels, and an actuator for vertically operating a ground working device connected to a rear portion of the fuselage; When operated, the front wheel transmission is switched from a standard state to a speed increasing state, the side brake on the turning center side is operated to a weak braking state by the power steering mechanism, and the actuator is automatically operated on the ascending side. Operating means for raising and lowering the ground working device by the operating means, and an operation signal based on an operation on an elevating lever or an elevating switch. Even, have configured to drive the actuator the ground work apparatus to raise and lower operation.

[0005]

When the operator operates the steering wheel to steer the front wheels right or left to start turning the aircraft, the front wheel transmission shifts from the standard state to the speed increasing state. When the switching operation is performed and the side brake on the turning center side is switched to the weak braking state by the power steering mechanism, and the aircraft starts to make a small turn, the ground working device that is being lowered is automatically raised. Thus, the operator only needs to perform the steering operation of the front wheels with the steering wheel, and does not need to operate the lifting lever or the like to perform the lifting operation of the ground work apparatus.

Further, in addition to operating the operating means to raise the ground working device, the ground working device can be raised and lowered by operating a lifting lever and a lifting switch.

[0007]

According to the first aspect of the present invention, when the operator operates the steering wheel to start turning the body, the front wheel transmission is switched from the standard state to the speed increasing state, and the center of turning is operated by the power steering mechanism. When the side brake on the side is switched to the weak braking state and the aircraft starts making a small turn, the ground work equipment is automatically raised,
At this time, there is no need for the operator to operate the lifting lever or the like to perform the lifting operation of the ground working device, and the operability at the time of turning can be improved.

[0008] When the turn is completed and the aircraft returns to the straight traveling state,
The operator can operate the operating tool (elevating lever, elevating switch, etc.) to lower the ground working device.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. [1] As shown in FIG. 10, the engine 3 is mounted on the front of the body supported by the front wheel 1 and the rear wheel 2, and the transmission case 4 is mounted on the rear of the body to form a four-wheel drive agricultural tractor. I have. A rotary tilling device 56 (corresponding to a ground working device) is connected to be movable up and down by one top link 53 and two lower links 55 at the rear of the transmission case 4. A pair of left and right lift arms 58 is swingably supported on the upper part of the transmission case 4, and the lift arm 58 and the lower link 55 are connected by a lift rod 59, and a hydraulic cylinder that swings the lift arm 58 up and down. 57 (corresponding to an actuator) are provided in the transmission case 4.

As shown in FIG. 2, motive power from the engine 3 is supplied to a traveling main transmission (not shown), a first auxiliary transmission (not shown), and a second auxiliary transmission (not shown) in a transmission case 4. The power is transmitted to the left and right rear wheels 2 from the rear wheel differential mechanism 5, and the power branched from the rear wheel differential mechanism 5 is transmitted from the front wheel transmission 7 to the front wheel transmission shaft 8 and the front wheel differential. The power is transmitted to the left and right front wheels 1 via the mechanism 6.

[2] Next, the front wheel transmission 7 will be described. As shown in FIG. 9, the power branched immediately before the rear wheel differential mechanism 5 is transmitted from the transmission gear 16 to the first standard gear 12, and the first speed increasing gear is transmitted through the first standard gear 12 and the transmission shaft 11. 13 is transmitted. Front wheel transmission shaft 8 to front wheel 1
A second standard gear 9 and a second speed increasing gear 10 are fitted to the outside so as to be relatively rotatable, and each of the first and second standard gears 12, 9 and the first and second speed increasing gears 13, 10 is engaged. are doing.

A shift member 14 is slidably fitted on the front wheel transmission shaft 8 in a spline structure, and when the shift member 14 is engaged with the second standard gear 9, the front wheel 1 has substantially the same speed as the rear wheel 2. The power is transmitted in the standard state driven by. Conversely, when the friction clutch 15 formed between the second speed increasing gear 10 and the front wheel transmission shaft 8 is pressed and operated by the shift member 14, the front wheel 1 is driven at a higher speed than the rear wheel 2. Power is transmitted in the state.

Next, the structure of the operation system of the shift member 14 of the front wheel transmission 7 will be described. As shown in FIG. 9, a shift fork 17 for the shift member 14 is externally fitted to an operation shaft 18 slidable in the axial direction via a spring 19 for flexibility, and a spring having a smaller urging force than the spring 19. By 20, the shift fork 17 is biased toward the occlusal side (standard state side) with the second standard gear 9. As shown in FIGS. 2 and 3, a pitman arm 22 for steering operation of the front wheel 1 is supported by a power steering mechanism 21.
Is fixed to the cam plate 23, and the longitudinal axis P of the body fixing portion is fixed.
Pin 2 of cam arm 24 supported swingably around 1.
4 a is engaged with the cam hole 23 a of the cam plate 23.
Then, a wire 25 is connected across the distal end of the cam arm 24 and the operation shaft 18 in FIG.

With the above structure, when the pitman arm 22 is swung from the straight traveling position to the right or left by a predetermined angle or more by operating the steering handle 26 shown in FIG. When the steering operation is performed to the right or left from the straight traveling position by a set angle or more), the cam arm 24 is swung to the left in the drawing by the cam action of the cam hole 23a and the pin 24a as shown in FIG. The wire 25 is pulled toward the cam arm 24. As a result, the operation shaft 18 and the shift fork 17 in FIG. 9 are slid to the left in the drawing, the shift member 14 presses the friction clutch 15 and the front wheel 1 is driven at an increased speed.

[3] As shown in FIG. 2, a pair of left and right side brakes 27 capable of independently braking the left and right rear wheels 2 are provided. Next, the operation structure of the left and right side brakes 27 will be described. As shown in FIG. 2, the pair of left and right side brakes 27 is
3 are provided. This brake operation mechanism 33 is shown in FIG.
As shown in FIG. 7, an L-shaped brake arm 28 is swingably supported around the axis P2, and the lower end of the paper surface of the brake arm 28 and the side brake 27 are linked to each other by a link rod 29. Have been. 2 and 3
As shown in FIG. 2, a pair of left and right side brake pedals 30 are provided on the right side of the control section of the aircraft, and one end of the side brake pedal 30 and one end of the brake arm 28 are connected to the link rod 3.
1 and the connection pin 32 for interlocking connection.

When the left side brake pedal 30 is depressed by the above structure, the link rod 31 is pulled upward as shown in FIG. 8, and the brake arm 28 swings counterclockwise in FIG. The link rod 29 operates the left side brake 27 to the braking side.

[4] Next, the linkage between the left and right side brakes 27 and the power steering mechanism 21 for the front wheels 1 will be described. As shown in FIGS. 6 and 7, an operation arm 34 is supported around the axis P2 of the brake operation mechanism 33 so as to be swingable independently of the brake arm 28.
A link arm 36 is swingably supported around a support pin 35 at the tip of the operation arm 34. A spring 37 for urging the link arm 36 clockwise in FIG.
A vertically long recess 36 a is formed on the left side of the paper of the link arm 36. As a result, the connection pin 32 of the brake arm 28 enters the recess 36 a of the link arm 36 by the urging force of the spring 37.

As shown in FIGS. 2, 3, and 5, a right operating arm 39 is swingably supported around a longitudinal axis P3 of a right frame 38 at the front of the body, and a right brake operating mechanism 33 is provided.
The support pin 35 of the operating arm 34 and the right operating arm 39 are linked by a spring 40 and a wire 41. A support shaft 42 is rotatably supported around a longitudinal axis P4 of the left frame 38.
The operation arm 43 is fixed, and the left second operation arm 4 is
4 is fixed. The support pin 35 of the operation arm 34 of the left brake operation mechanism 33 and the left second operation arm 44 are linked by a spring 40 and a wire 41. The right operation arm 39 and the left second operation arm 44 are shown in FIG.
Are fixed to the left and right frames 38. As shown in FIGS. 7 and 6, a spring 45 for urging the operation arm 34 clockwise in FIG. 7 is attached to the support pin 35 of the operation arm 34 of the brake operation mechanism 33.

With the above structure, for example, when the front wheel 1 is steered to the left by a predetermined angle or more, as shown in FIG. 4, the pitman arm 22 swings downward in the drawing, and the cam plate 23 moves to the left first operation position. The arm 43 comes into contact with the arm 43, and the left first and second left operation arms 43 and 44 are pivoted clockwise in the drawing. Thus, the left wire 41 is pulled toward the left first and second left operation arms 43 and 44, and the operation arm 34 of the left brake operation mechanism 33 swings counterclockwise in the drawing.

In this case, as shown in FIG.
6, the connecting pin 32 of the brake arm 28 is inserted into the recess 36a.
, The linking arm 36 is pulled upward with respect to the plane of the paper with the swing of the operation arm 34, and the brake arm 28 is also rocked counterclockwise with the engagement of the concave portion 36 a and the connecting pin 32, Left side brake 27
Is operated in a weak braking state. The weak braking state of the side brake 27 refers to a state in which the rear wheel 2 on the turning center side (braking side) is dragged along with the turning of the aircraft, and the braking force of the side brake 27 is lost, so that the turning center side (braking). side)
The rear wheel 2 slightly rotates. in this case,
As shown in FIG. 4, both ends of the outer 41a of the left and right wires 41 are fixed to a fixed bracket 54 by a pair of nuts 47 so that the fixing position of the outer 41a can be adjusted. The amount of pull operation (the amount of operation of the side brake 27 toward the braking side) is adjusted so that the braking force of the side brake 27 can be finely adjusted.

As described above, when one of the side brakes 27 is operated in a weak braking state by the steering operation of the front wheel 1, the wire 25 is pulled by the action of the cam plate 23 and the cam arm 24 shown in FIG. As described above, the front wheel transmission 7 is switched from the standard state to the speed increasing state. Thus, when the front wheel 1 is steered to a predetermined angle or more, the front wheel transmission 7 is switched to the speed increasing state, and the front wheel 1 is driven to increase the speed. The side brake 27 of the rear wheel 2 is operated to a low braking state.

As shown in FIGS. 4 and 7, an elongate hole 31a is provided in the link rod 31 on the side brake pedal 30 side, and a connecting pin 32 is inserted into the elongate hole 31a. Thus, even if the front wheel 1 is steered beyond the set angle as described above and the operation arm 34 and the brake arm 28 swing counterclockwise as shown in FIG.
Only the connecting pin 32 moves upward in the drawing, and the side brake pedal 30 is not operated. In the state shown in FIG. 3 (the state in which the wire 41 is not pulled in the straight-ahead state), when the side brake pedal 30 is depressed to move the link rod 31 upward in the drawing, the brake is applied as shown in FIG. The arm 28 swings in the counterclockwise direction on the drawing sheet, and the connecting pin 32 simply moves upward in the drawing in the concave portion 36a of the linking arm 36. The operation arm 34 and the linking arm 36 are in the postures shown in FIGS. It does not move as it is.

[5] Next, when the front wheel 1 is steered beyond a set angle, the side brake 27 on the turning center side is automatically operated to the weak braking state as described above, and is not operated. The structure for switching the state will be described. As shown in FIG. 2 and FIG. 7, an operation lever 50 is swingably supported by a control section of the fuselage, and extends over each of the link arms 36 of the left and right brake operation mechanisms 33 and the operation lever 50. A pair of wires 51 are connected.

The state shown by the solid line in FIG.
Is operated to the ON position, and the link arm 36 of the left and right brake operation mechanism 33 is pivoted clockwise in the drawing sheet, and the connection pin 32 on the brake arm 28 side is inserted into the concave portion 36a of the link arm 36. It is in a state of being intruded. In this state, for example, when the front wheel 1 is steered to the left by a set angle or more, the operation arm 34 of the left brake operation mechanism 33 swings counterclockwise in FIG.
The engagement between the concave portion 36a and the connecting pin 32 causes the brake arm 28 to swing in the counterclockwise direction on the paper surface, and the left side brake 27 to be operated in a weak braking state.

Next, when the operating lever 50 is operated to the OFF position, the pair of wires 51 is pulled toward the operating lever 50, and the link arms 36 of the left and right brake operating mechanisms 33 are operated as shown by the two-dot chain line in FIG. The rocking operation is performed in the counterclockwise direction on the paper surface, and the concave portion 36a of the link arm 36 is separated from the connection pin 32 on the brake arm 28 side to the right in the paper surface. In this state, for example, even if the front wheel 1 is steered to the left by a set angle or more, only the operation arm 34 of the left brake operation mechanism 33 swings in the counterclockwise direction, and the brake arm 28 moves in the counterclockwise direction. No swing operation is performed in the direction, and the left side brake 27 is not operated in the weak braking state.

[6] Next, the lifting operation of the rotary tilling device 56 will be described. This agricultural tractor has automatic tillage depth control means for maintaining the rotary tillage device 56 at a set height from the ground and keeping the tillage depth constant, and position control means for maintaining the height of the rotary tillage device 56 relative to the body at a set position. Is provided in the control device 49.

As shown in FIG. 1, the rotary tilling device 56
A tillage depth sensor 56b for detecting the vertical swing angle of a rear cover 56a provided to be vertically swingable. Thereby, the automatic cultivation depth control means operates the hydraulic cylinder 5 so that the detection value of the cultivation depth sensor 56b becomes the set cultivation depth of the potentiometer type cultivation depth setter 48 provided on the machine body.
By switching the control valve 60 for 7, the rotary tilling device 56 is automatically raised and lowered by the hydraulic cylinder 57 and the lift arm 58.

An angle sensor 5 for detecting the vertical angle of the lift arm 58 with respect to the machine body is provided at the base of the lift arm 58.
2 are provided. Thereby, the position control means switches the control valve 60 so that the detection value of the angle sensor 52 becomes the target value set by the elevating lever 61 (corresponding to an operation tool which is manually operated) provided on the body. By operating the hydraulic cylinder 57, the lift arm 58 is swung up and down. Therefore, when the rotary tilling device 56 is located above the ground, the operator operates the elevating lever 61 to arbitrarily change the position of the rotary tilling device 56 with respect to the body up and down by the position control means. can do. Then, when the rotary tillage device 56 is lowered by the elevating lever 61 to a position in contact with the ground, the state automatically switches to a state in which the automatic tillage depth control means operates, and the detection value of the tillage depth sensor 56b is used as the tillage depth setting device 48.
The rotary tillage device 56 is automatically moved up and down so as to reach the set tillage depth.

An elevating switch 62 (corresponding to an artificially operated operating tool) for raising the rotary tilling device 56 to a predetermined height with respect to the body at a stretch is provided. Accordingly, when the raising / lowering switch 62 is pressed and turned on, the control valve 60 is operated in preference to the position control means and the automatic plowing depth control means, and the rotary tillage device 56 is raised at a stroke to a predetermined height with respect to the body. Because
When the raising / lowering switch 62 is pressed again and turned off, the rotary tillage device 56 is lowered to the original position,
The state returns to the above-described position control means or automatic plowing depth control means.

[7] Next, the relationship between the raising / lowering operation of the rotary tilling device 56 and the front wheel transmission 7 and the left and right side brakes 27 will be described with reference to FIGS. As shown in FIGS. 2 and 3, when the cam arm 24 for the front wheel transmission 7 is swung, the limit switch 64 with which the cam arm 24 comes into contact is fixed inside the left frame 38. The control device 49 is provided with an automatic ascending means for automatically ascending the rotary tillage device 56 during turning.

As a result, when the changeover switch 63 (see FIG. 1) (corresponding to an operation device which is manually operated) for the automatic ascending means is pressed once to turn on (step S).
2) The lamp 63a incorporated in the changeover switch 63 is turned on (step S3), and the automatic ascent means is set to the operating state (step S4) (corresponding to the changeover means).

In this state, when the airframe reaches the ridge, the operator operates the control handle 26 to move the pitman arm 2.
When the front wheel 1 is swung from the straight-ahead position to, for example, a left angle or more (when the front wheel 1 is steered to the left from the straight-ahead position to a set angle or more), as shown in FIG. The front wheel transmission 7 is switched to the speed-up state and the front wheel 1 is driven to speed-up, and the left first operation arm 43 is rocked by the cam plate 23 to move the left wheel. The side brake 27 is operated to a weak braking state.

At the same time, the cam arm 24 comes into contact with the limit switch 64 (step S5), and the control device 49 switches the control valve 60 in response to a signal from the limit switch 64 to automatically rotate the rotary tillage device 56.
Is largely lifted from the ground (step S6).
Also, if the operator operates the elevating lever 61 to the ascending side or pushes the elevating switch 62 to turn it on before the signal is received from the limit switch 64, the rotary tillage device 56 is operated to ascend. As described above, when the front wheel 1 is steered beyond the set angle, the front wheel transmission 7 is switched from the standard state to the speed increasing state, the power steering mechanism 21 operates the side brake 27 on the turning center side to a weak braking state, and the actuator 57 Is referred to as operating means for automatically operating the ascending side.

When the 180 ° turn at the end of the ridge is completed as described above, the operator presses the elevating switch 62 or operates the elevating lever 61 downward (step S7). The control valve 60 is switched by 49, and the rotary tilling device 56 in the ascending state is operated to descend (step S8) (corresponding to the descending operation means).

In the above state, when the changeover switch 63 is pressed again to turn it off (step S).
9) The lamp 63a goes out (step S10), the process proceeds from step S1, S2 to step S11, and the automatic ascent unit is set to the operation stop state (corresponding to the switching unit).
In this state, as described above, even if the pitman arm 22 is swung from the straight-ahead position to the right or left angle or more, the rotary tilling device 56 is not automatically moved up, and the operator can use the up / down switch 62. Is operated, or the elevating lever 61 is operated to the ascending side to operate the rotary tillage device 56 ascending.

Then, once the engine 3 is stopped (step S1), the automatic ascent means is set to the operation stop state (step S11) (corresponding to the check means). Therefore, when the engine 3 is restarted by the key switch 65 in FIG. 1, the automatic ascent means is set to the operation stop state, and unless the changeover switch 63 is pressed to turn on the automatic ascent means, the automatic ascent means is activated. It has been stopped.

[Alternative Embodiment] In the aforementioned embodiment, one limit switch 64 is provided on the cam arm 24 for the front wheel transmission 7.
However, as shown in FIG. 13, a pair of limit switches 64 may be provided on each of the right operation arm 39 and the left second operation arm 44.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a diagram showing a linked state of a rotary tillage device such as lifting and lowering, a lifting lever, a lifting switch and a changeover switch.

FIG. 2 is a plan view showing a linked state of a front wheel power steering mechanism, a front wheel transmission, and left and right side brakes.

FIG. 3 shows a state in which a front wheel is operated to a straight-ahead position;
Plane and side views showing the linked state of the front wheel power steering mechanism and the left and right brake operation mechanisms

FIG. 4 is a plan view and a side view showing a linked state between a power steering mechanism for the front wheels and left and right brake operating mechanisms when the front wheels are steered to the left by a set angle or more.

5 is a rear view of the vicinity of the power steering mechanism for the front wheels in FIG. 3 as viewed from the right side in FIG. 3;

FIG. 6 is a rear view of the vicinity of the brake operating mechanism in FIG. 3 as viewed from the right side in FIG. 3;

FIG. 7 is a side view showing a linked state of the left and right brake operation mechanisms and the left and right side brakes and the side brake pedal.

8 is a side view showing a state in which a side brake pedal is depressed from the state shown in FIG. 7;

FIG. 9 is a longitudinal sectional side view of the front wheel transmission.

FIG. 10 is an overall side view of the agricultural tractor.

FIG. 11 is a diagram showing a flow in the first half of elevating control for the rotary tillage device;

FIG. 12 is a diagram showing a flow of the latter half of the elevating control for the rotary tillage device;

FIG. 13 is a plan view and a side view showing a linked state between a front wheel power steering mechanism and left and right brake operation mechanisms in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 3 Engine 7 Front wheel transmission 21 Power steering mechanism 27 Side brake 56 Ground work device 57 Actuator 61 Lifting lever 62 Lifting switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B62D 11/08 B62D 11/08 D 49/00 49/00 K F (72) Inventor Satoshi Iida Sakai, Osaka 64 Ishizu-Kitacho, Ishizu-shi Kubota Sakai Works

Claims (1)

[Claims] 1. A standard state in which the front wheel (1) and the rear wheel (2) are driven at substantially the same speed, and a speed-up state in which the front wheel (1) is driven at a higher speed than the rear wheel (2). An operable front wheel transmission (7), a power steering mechanism (21) for steering the front wheel (1) right or left, and braking the left and right rear wheels (2) and (2) independently. A possible side brake (27) and an actuator (57) for lifting and lowering a ground working device (56) connected to the rear part of the fuselage, and when the front wheel (1) is steered, the front wheel The transmission (7) is switched from the standard state to the speed-up state, the power steering mechanism (21) operates the side brake (27) on the turning center side to a weak braking state, and the actuator (57) moves upward. Operating means to activate automatically Only, in addition to elevating and lowering the ground working device (56) by said operating means, by an operation signal based on the operation of the lift lever (61) or lift switch (62),
A four-wheel drive agricultural tractor configured to drive the actuator (57) to raise and lower the ground working device (56).