JPH1044707A - Tread adjusting device for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust a tread with ease by constituting a tread adjusting device so as to be able to control the right and left wheels to move them in the tread direction so that the tread width of the right wheels and the width of the left wheels become equal to the tread width set by a setting operation section and prevent the tread width of the right and left wheels from substantially changing when an engine starts by avoiding the width set by the operation section from substantially changing from the actual tread width. SOLUTION: In order to set the tread width of the right and left wheels of a tractor in a given setting range infinitely or in a plurality of stages, a tread adjusting device is provided with a manually operable setting section 61, a hydraulic device which moves the wheels in a tread direction according to the setting position set by the operation section 61 and a restriction means, which restricts the setting operation section 61 to set a range only within a given range based on the actual tread width by feeding-back the actual tread width of the right and left wheels to the setting operation side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tractor tread adjusting device.

[0002]

2. Description of the Related Art A conventional tractor tread adjusting device is:
For example, this conventional device is disclosed in Japanese Patent Application Laid-Open No. 3-182808. In this conventional device, an axle case of a rear wheel is made extendable and contractable, and a hydraulic cylinder for extending and contracting the axle case is provided. The switching valve is provided so that the switching can be manually performed by lever operation.

[0003]

According to the above prior art, in order to obtain a desired tread width, it is necessary to measure the tread width while operating a lever, and the operation is very complicated. It was difficult to do. Therefore,
The present inventors provide a manually operable setting operation unit to set the tread width of the left and right wheels of the tractor in a predetermined setting range steplessly or in a plurality of steps, and set a wheel according to the setting position of the operation unit. By operating a hydraulic device that moves the wheels in the tread direction, a device that automatically controls the movement of the wheels in the tread direction to achieve the target tread width has been developed.

[0004] However, if the setting operation section is operated when the engine is stopped and the engine is started in a state where the set width by the operation section and the actual tread width of the left and right wheels are different, the engine is inadvertently started when the engine is started. Wheels are moved in the tread direction. In particular, when the difference between the set width and the actual tread width is large, the tread is unexpectedly greatly changed at the time of starting the engine, and the wheels hit an obstacle present on the side of the tractor to damage the axle, There is a fear that the wheels may hit the tractor body side.

In view of the above, the present invention is configured to control the movement of the left and right wheels in the tread direction so as to have the tread width set by the setting operation section, so that the tread adjustment operation can be easily performed, and the setting operation section can be easily controlled. It is an object of the present invention to prevent the left and right wheels from being significantly tread-changed when the engine is started by preventing the set width from largely differing from the actual tread width.

Further, the present invention performs an initialization process for comparing the set tread width and the actual tread width by the setting operation unit at the time of starting, so that the tread can be prevented from being accidentally changed at the time of starting the engine. The purpose is to.

[0007]

Means for Solving the Problems In order to achieve the above object, the present invention has taken the following technical means. That is, the tread adjusting device of the present invention includes a setting operation unit that can be manually operated to set the tread widths of the left and right wheels of the tractor in a predetermined setting range in a stepless or multiple steps, and at a setting position of the operation unit. The hydraulic device that moves the wheels in the tread direction in response to the actual tread width of the left and right wheels is fed back to the setting operation unit side to regulate the settable range of the setting operation unit only within a predetermined range based on the actual tread width Feedback restricting means.

[0008] With this feedback restriction means, the setting operation section can be set only within a predetermined range based on the actual tread width, and the tread width set by the setting operation section does not become larger than the actual tread width. Even if the setting operation part is operated when the engine is stopped, the automatic tread change amount at the time of engine start is suppressed to a small range,
It is guaranteed that the tread will not change significantly.

Further, when the setting operation section is operated after the engine is started, the hydraulic device is actuated in response thereto, and the actual tread width is changed to follow the set tread width. Therefore, by operating the setting operation unit in accordance with the operating speed of the hydraulic device, the settable range by the feedback control unit is also shifted, so that the setting operation unit can be set and operated over the entire setting range.

Further, since the set width by the setting operation section corresponds to the actual tread width, the target tread width can be easily and quickly set without the operator having to measure the tread width. Also, even if the actual tread width is temporarily changed by the wheels hitting an obstacle such as a rock while traveling, the hydraulic device is operated so that the set width is set by the setting operation unit, and the target set width is set. Since it is corrected, it is guaranteed that the set width and the actual tread width match.

Further, the tread adjusting device of the present invention comprises a casing provided with a setting dial which can be rotated to set the tread width of the left and right rear wheels of the tractor in a predetermined setting range in a stepless manner or in a plurality of steps. A hydraulic device for moving a rear wheel in a tread direction in accordance with a setting position of the dial, wherein the casing is disposed near a driver's seat of a tractor, and treads for left and right rear wheels are provided in the casing. A rotor interlocking with the movement in the direction is provided on the same axis as the dial, and includes a restricting means for restricting a relative rotation angle of the dial with respect to the rotor within a predetermined range.

Therefore, in addition to the above operation, the setting operation section is constituted by a dial, and the casing provided with the dial is provided near the driver's seat, thereby enabling easy and quick operation from the driver's seat. In addition, the configuration can be made compact, and a narrow space near the driver's seat can be effectively used. If the restricting means is provided with a circumferentially long hole provided on the rotor side and a pin provided on the dial side so as to engage with the long hole, the structure can be simplified and the cost can be reduced.

A tread adjusting device according to the present invention further comprises a setting operation section which can be manually operated to set the tread width of the left and right wheels of the tractor in a predetermined setting range in a stepless manner or in a plurality of steps; A hydraulic device to be moved to
A control unit for electronically controlling the operation of the hydraulic device according to the setting width by the setting operation unit.The control unit is fed back with the actual tread widths of the left and right wheels, and the control unit controls the left and right wheels when starting. It is configured to perform an initialization process of comparing the actual tread width with the set width by the setting operation unit.

If the control unit is configured to electronically control the hydraulic device, various control contents requested by the program of the control unit can be obtained, and the tread width setting operation can be performed more easily. Become. Further, when the actual tread width of the left and right wheels and the set width set by the setting operation unit are different due to the initialization process performed at the time of starting, the operator is notified of the fact, the operation of the hydraulic device is prohibited, and various operations are performed. Control can be performed, so that it is possible to prevent the tread change control from being performed accidentally.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Right and left front wheels 12 and left and right rear wheels 13 are mounted on the front and rear of the vehicle body 11 of the tractor 10 shown in FIGS. 22 and 23, respectively. The rear wheel 13 is covered with a fender 16.

An engine is mounted on the front of the vehicle body 11,
The engine is covered with a hood 17. Although not shown, a three-point link mechanism for mounting various working devices is provided at a rear portion of the vehicle body 11, and the mechanism is configured to be able to move up and down by a hydraulic elevating device. A cabin 18 is mounted on the vehicle body 11, and a driving control section is provided in the cabin 18. That is, a driver's seat 19 is provided in the cabin 18, a steering handle 20 is provided in front of the driver's seat 19, and various operation levers (not shown) are provided near the driver's seat 19.
Are arranged.

FIGS. 1 to 13 show a tread adjusting device according to a first embodiment of the present invention. To be described below, as shown in FIG. A brake case 22, a rear axle case 23, and a rear axle 24 are mounted on both left and right sides of a rear portion of the case 21. The rear axle case 23 is configured to extend and contract from a fixed case 25 and a movable case 26 slidably provided in the left and right axial direction. The fixed case 25 is connected to the transmission case 2 via the brake case 22.
1 attached and fixed.

A brake 28 is provided in the brake case 22 for braking a differential yoke shaft 27 projecting left and right outward from a rear wheel differential device in the transmission case 21. It is operatively connected to the axle 24. The rear axle 24 has a planetary reduction gear 29
Is connected to a transmission shaft 30 connected to the tractor body 11 via a spline cylinder shaft 31 so as to be movable in the axial direction which is the left-right direction with respect to the tractor body 11. The transmission shaft 30 is supported by a fixed case 25 via a bearing 32, and the rear axle 24 is supported by a movable case 26 via bearings 33 and 34, and a flange 35 at the outer end of the rear axle 24.
The disk 13a of the rear wheel 13 is mounted on the rear wheel.

On the rear side of the rear axle case 23, a rear wheel 13 is provided.
A hydraulic cylinder 36 (hydraulic device) for moving the rear axle 24 in the axial direction in order to move the rear axle 24 in the tread direction is disposed in parallel and housed in a holding case formed integrally with the fixed case 25. . The hydraulic cylinder 36
Piston rod 38 whose inner end is fixed to fixed case 25
And the piston 3 fixed to the outer end of the piston rod 38
9 and a cylinder body 40 slidably fitted to the piston 39 and the piston rod 38.
The piston rod 38 has a cylindrical shape, and an inner cylinder 41 is inserted through the piston rod 38 so as to form an oil passage inside and outside, and the oil passage is provided in each oil chamber in a cylinder body 40 defined by a piston 39. 42 and 43 are connected.

An interlocking body 44 fixed to the outer end of the movable case 26 is fixed to the outer end of the cylinder body 40. The cylinder body 40, the movable case 26 and the rear axle 24 are fixed via the interlocking body 44. And are integrally linked.
A cylindrical stopper 45 is loosely fitted in the oil chamber 43 of the cylinder body 40.

The structure inside the rear axle case 23 is the same for both the left and right wheels, and the right and left rear wheels 13 can be tread-changed independently of each other by extending and retracting the respective hydraulic cylinders 36. FIG. 12 shows a hydraulic circuit including left and right hydraulic cylinders 36. In this hydraulic circuit, the hydraulic pump 50 is configured to supply hydraulic oil in an oil tank 51 via an oil filter 52 to a hydraulic device for lifting and lowering a work implement provided at a rear portion of a tractor, and to hydraulic cylinders 36 on right and left rear axles. And is driven by an engine mounted on the front of the tractor body 11.

A priority valve 54 composed of a flow control valve is provided in the middle of the oil supply path 53 to the hydraulic cylinder 36, and a part of the hydraulic oil supplied from the hydraulic pump 50 The oil is supplied to a cylinder 36 and other oil is supplied to a hydraulic elevating device at the rear of the tractor 10. For example, if the capacity of the hydraulic pump 50 is 6
The amount of hydraulic oil supplied to the hydraulic cylinders 36 on the left and right axles is 3 liters / minute.

A relief valve 55 is provided on the downstream side of the priority valve 54 and on the upstream side of the cylinder 36 to prevent the pressure in the hydraulic cylinder 36 and the pressure in the oil supply pipe from abnormally increasing. The hydraulic cylinders 36 are connected in series, with the hydraulic cylinder 36 on the left axle located upstream and the hydraulic cylinder 36 on the right axle located downstream. Each hydraulic cylinder 36 is provided with a corresponding three-position switching type electromagnetic switching valve 56. The solenoid-operated switching valves 56 include a cylinder extending solenoid 57 for operating the switching valve 56 to move the rear wheel 13 in the tread expanding direction, and a switching valve 56 for operating the rear wheel 13 in the tread reducing direction. A solenoid 58 for shortening the cylinder is provided, and a switching operation is performed from the neutral position by exciting either the extension solenoid 57 or the compression solenoid 58.

In the vicinity of the driver's seat 19, there is provided a tread setting operation section 61 which can be manually operated and a casing 63 provided with an actual tread width display section 62 by the operation section 61. With the extension solenoid 57
Alternatively, the hydraulic cylinder 36 (hydraulic device) can be controlled by exciting one of the compression solenoids 58.

In this embodiment, as shown in FIGS. 22 and 23, a casing 63 is provided on the left side of the driver's seat 19, so that the operator on the driver's seat 19 can easily operate the setting operation section 61 manually. In addition, the actual tread width display portion 62 is made visible. Note that the casing 63 may be disposed on the right side of the driver's seat 19 or on the front and rear sides. As shown in FIGS. 1 to 5, the casing 63 is formed of a heat-resistant resin such as an ABS resin in the shape of a rectangular box that is open downward.
Bolt holes 6 for mounting are provided in the corners of the casing 63.
4 are provided. A pair of tread setting operation sections 61 are provided side by side on this single casing 63, and each operation section 61 corresponds to a change in the tread of the left and right rear wheels 13 respectively. The rear wheels 13 are configured to be independently movable in the left-right width direction (tread direction).

Each of these tread setting operation sections 61 is constituted by a dial which is rotated by manual operation.
m, 10 in the range of 1280 mm (minimum width tire)
The tread width of each of the left and right rear wheels 13 can be set in mm units. It is preferable that the setting operation unit 61 is configured to be switchable in a plurality of steps as described above. However, the setting operation unit 61 can be switched in a stepless manner.

The casing 63 is provided with a regulating member 65 for regulating the operation range of the setting operation section 61 so that the position can be changed so that the minimum setting limit width of the tread width can be switched to a plurality of types. 4 and 9.
As shown in FIG. A short pin 65a is integrally connected to the pin 65.
5a and 65b are removably attached to a pair of mounting holes 67 provided in the casing 63 for inserting and supporting them. The short pin 65a serves to prevent the restriction member 65 from being accidentally displaced from the mounting hole 67. In addition, long pin 6
By replacing the position of the short pin 65a with the position of the short pin 65a in the mounting hole 67, the minimum set limit width of the tread width can be switched to a plurality of types.

An operating section 61 is provided on a first rotor 70 to be described later.
An engagement portion 66 that engages with the regulating member 65 is provided in order to regulate the range of the rotation operation. Therefore, when a wide wheel is mounted as the rear wheel 13, in order to avoid contact between the rear wheel 13 and the fender 16, the mounting position of the regulating member 65 is exchanged with the position of the short pin 65 a and the dial 61 is used. The minimum setting width is regulated to be 1320 mm.
It is to be noted that a rotation regulating engagement portion 66 for the regulation member 65 is provided.
Is provided on the first rotor 70 in the present embodiment, but may be provided on the dial 61.

A scale 62 constituting an actual tread width display portion is provided around the dial 61 on the outer surface of the casing 63 (the upper surface in the illustrated example), and left and right corresponding to the set position of the dial 61 are provided. The actual tread widths of the rear wheels 13 are displayed, so that the driver's seat 19 can easily recognize the current tread width of the left and right rear wheels 13.

In the box-shaped casing 63, each operation section 61 is provided.
Rotor 70, second rotor 71, and reel 73 of Bowden wire 72, which is linked to rear axle 24.
Are each stored. One set of the first rotor 70, the second rotor 71, and the reel 73 are arranged on the same axis. The first rotor 70 is rotatably accommodated in a cylindrical holding portion 63a formed in the casing 63,
At the center of the rotor 70, a top plate 63 of a casing 63 is provided.
b, a shaft 74 protruding upward from the shaft 7 is provided.
A setting operation section 61 is detachably attached to the operation section 4, and the operation section 61 and the first rotor 70 are connected so as to rotate integrally. The stopper pin 65 is detachable by removing the setting operation section 61 from the shaft section 74.

A latch (not shown) is formed on the inner periphery of the holding portion 63a, and a positioning mechanism 75 for engaging with the latch is provided on the outer periphery of the rotor 70. The operability is improved by making it possible to surely perform the turning operation by the pitch (tread width: 10 mm). The illustrated positioning mechanism 75 is composed of a steel ball that engages with the latch and a coil spring that urges the ball in a direction that engages with the latch, but may have another structure. .

The second rotor 71 is disposed below the first rotor 70 so as to be opposed to the first rotor 70. The second rotor 71 is rotatably fitted to a boss 80 provided at the center of the first rotor 70 so as to project downward. I have. The second rotor 71 is received from below by a substrate 82 fitted into the casing 63 from below and fixed by tapping screws 81, and a boss provided at the center of the second rotor 71 so as to protrude downward. The portion 83 is rotatably inserted into and supported by a support hole 84 provided in the substrate 82.

Further, between the first rotor 70 and the second rotor 71, an operation angle restricting means for restricting a relative rotation operation angle of the first rotor 70 with respect to the second rotor 71 to a predetermined range is provided. . The means comprises an engagement pin 85 provided on the first rotor 70 so as to protrude downward, and an engagement hole 86 provided on the second rotor 71 so that the pin 85 engages. The engagement hole 86 is formed in a long hole shape extending in the circumferential direction,
The first rotor 70 can be rotated with respect to the second rotor 71 within the range of the elongated hole.

The reel 73 is disposed below the substrate 82, and a bolt 8 is mounted on the boss 83 of the second rotor 71.
8 are integrally attached and fixed. On the outer circumference of the reel 73, a winding groove 89 for guiding and holding the inner 72a of the Bowden wire 72 is provided, and a locking portion 90 for locking and holding a connector attached to the inner 72a is provided. An end of the outer 72 b of the Bowden wire 72 is attached to a substantially central portion of the side wall of the casing 63 in the left-right direction.

As shown in FIGS. 10 and 11, the other end of the Bowden wire 72 has an outer 72b attached and fixed to the tractor body 11 via a long plate-shaped bracket 91, and an inner 72a. It is attached and fixed to the interlocking body 44 fixed to the outer end of the rear axle 24 via an L-shaped bracket 92. The outer 7 to the bracket 91
By adjusting the attachment of the inner tread 2b or the attachment of the inner 72a to the bracket 92, the tread width indicated by the actual tread display portion 62 can be adjusted to be the true actual tread width. .

The inner portion of the reel 73 has
A torsion coil spring 95 (urging means) for urging the reel 73 to rotate in the direction of winding the 2a is mounted. One end of the spring 95 is connected to the reel 7.
3 and the other end is locked to a projection 96 provided on the casing 63. It should be noted that a through hole 97 of the projection 96 is formed in the substrate 82.

Accordingly, when the rear axle 24 moves right and left outward, the inner 72a is paid out from the reel 73, and the reel 73 and the second rotor 71 are rotated in that direction. When moved inward, the reel 73 is biased by the spring 95.
And the second rotor 71 is rotated in the winding direction so that the reel 7
3, the inner 72a is wound up. In this way,
In the present embodiment, a feedback unit that feeds back the actual tread width of each of the right and left rear wheels 13 to the setting operation unit 61 is configured as a mechanical type mainly including the Bowden wire 72 described above.

When the setting operation section 61 and the display section 62 indicate the actual tread width, the first rotor 70, the second rotor 71 and the substrate 82 are electrically disconnected from each other, and the value indicated by the display section 32 is displayed. Is provided with a contact (switch) that is electrically connected when is different from the actual tread width. These contact points are connected to the extension solenoid 57 and the compression solenoid 58 of the above-mentioned left and right electromagnetic switching valves 56, so that the hydraulic cylinder 24 can be controlled by the setting operation section 61.
A control circuit including the contact (118) will be described later.

That is, on the upper surface of the second rotor 71 (the surface facing the first rotor 70), as shown in FIG. 6, a central ring-shaped positive conducting portion 101 made of a copper plate is formed. In addition, two semicircular arc-shaped negative conducting portions 102 and 103 are formed on the outer peripheral side of the conducting portion 101 so as to face each other. A slight space is provided between the ends of the pair of negative-side conducting portions 102 and 103 to form an insulating portion 104.

On the other hand, the first rotor 70 has the structure shown in FIGS.
As shown in the figure, the positive-side conductive portion 101 and the negative-side conductive portion 10
A conductive member 105 is provided for electrically connecting either one of the second and third members. This conductive member 105
Is made of a copper plate having a width extending over the positive-side conductive portion 101 and the negative-side conductive portions 102 and 103.
And is urged in a direction of pressing against the conductive portions 101, 102, and 103 by a spring 107 housed at the back of the recess 106.

When the actual tread width display section 62 indicates the actual actual tread width of the left and right rear wheels 13, the display section 6 is positioned so that the conductive member 105 is located on the insulating section 104.
2 corresponds to the insulating portion 104. At this time, the pin 85 of the restricting means is configured to be disposed at the center of the elongated hole 86, and is set by one pitch (equivalent to a tread width of 10 mm) in the direction of expansion and contraction with respect to the actual tread width. 61 is rotatable relative to the second rotor 71.

As shown in FIG. 6, when the conducting member 105 is located on the insulating portion 104 and the display portion 62 displays the actual tread width, the positive conducting portion 101 and the negative conducting portions 102, 1 are displayed.
When the setting operation unit 61 is rotated from the neutral position or the second rotor 71 is rotated together with the reel 73, the positive conduction unit 101 is switched to the negative conduction unit 102 or 103. Is electrically connected to the other.

On the upper surface of the substrate 82 (the surface facing the second rotor 71), as shown in FIG. 8, a ring-shaped positive conducting portion 111 on the center side and a semicircular pair on the outer peripheral side are formed. Are formed. This substrate 82
Positive-side conductive portion 111 of the second rotor 71 and the positive-side conductive portion 10 of the second rotor 71
1 is conducted through a coil spring 114 and a conductive member 115 mounted on the second rotor 71, and similarly, the respective negative-side conducting portions 112 and 113 of the substrate 82 are connected to the corresponding second rotor 71. The conduction is made to the negative conduction parts 102 and 103, respectively. The conductive portions 111 of these substrates 82,
Conductive wires 116 are connected to 112 and 113, respectively. These conductive wires 116 are bundled and pulled out of the casing 63, and a connector 117 is provided at an end thereof.
It is detachably connectable to a wiring connector on the tractor vehicle body 11 side.

The positive conducting portion 111 is connected to a power source mounted on the tractor vehicle body 11 via one of the wirings. One of the negative conducting portions 112 and 113 is connected to the extension solenoid 57, and the other is the compression solenoid 58. Connected to
In order to control the hydraulic cylinder 24 by the setting operation unit 61, a contact 118 (switch) provided in a power supply path to the solenoids 57 and 58 for expanding and contracting the electromagnetic switching valve is configured.

FIG. 13 shows a first embodiment of an electric control circuit having a contact 118 for controlling the operation of the electromagnetic switching valve 56, and is a control circuit having an alarm device. FIG. 12 described above.
Since the left and right hydraulic cylinders 36 are connected in series in one hydraulic circuit, it is necessary to operate only one of them. Therefore, in the control circuit of the present embodiment, when the left and right contacts are energized, the left telescopic solenoid 5
7, 58 are operated with priority.

That is, the telescopic solenoid 5 for the right axle
A relay 120 is provided in the middle of the power supply path to the power axles 7 and 58. The relay 120 is operated when the telescopic solenoids 57 and 58 for the left axle are energized and operates when the telescopic solenoids 57 and 58 for the right axle are extended. The power supply path to the solenoids 57 and 58 is cut off. An alarm device 121 is connected to the control circuit of the present embodiment, indicating that the telescopic solenoids 57 and 58 are being excited, that is, that the hydraulic device 36 for changing the tread is being operated. The alarm device 121 is provided near the driver's seat 19. Note that the alarm device 121 is preferably provided on the casing 63. As such an alarm device, a lamp, a buzzer, or the like can be employed.

The alarm device 121 includes telescopic solenoids 57 and 58 for the left axle and telescopic solenoids 5 for the right axle.
Each of the solenoids 57 and 58 is electrically connected in parallel, and informs the operator that any one of these solenoids 57 and 58 is operating.
According to the tread adjusting device, since the hydraulic pump 50 is not operating while the engine is stopped, the hydraulic cylinder 36 does not extend and contract even if the contact 118 is connected by operating the setting operation unit 61, and the rear wheels 13 Tread width is not changed. If the tread width is not changed, the reel 73 connected to the rear axle 24 via the Bowden wire 72 and the second
Since the rotor 71 also does not rotate, it is possible to prevent the setting operation section 61 whose rotation operation angle with respect to the second rotor 71 is restricted from being largely rotated while the engine is stopped.
It is possible to prevent the rear wheel 13 and the rear axle 24 from unexpectedly largely moving when the engine is started. The second rotor 7
The rotation restricting range of the first rotor 70 with respect to 1 is equal to one pitch (tread width 10 mm) in each of the tread expanding and contracting directions.
Min), but may be two pitches.

When the setting operation section 70 is rotated by one pitch in either the tread expanding direction or the reducing direction to adjust the tread of each rear wheel 13 after the engine is started, the transmission member provided on the first rotor 70 is rotated. The positive-side conductive portion 101 of the second rotor 71 and one of the negative-side conductive portions 102 and 103 are electrically connected to each other via 115 (that is, the contact 11
8 is closed), and the extension solenoid 57 or the compression solenoid 5
8, the electromagnetic switching valve 56 is operated, and pressure oil is supplied to one of the oil chambers 42 and 43 of the hydraulic cylinder 36,
The rear axle 24 is moved in the axial direction by one pitch (10 mm).

Then, as the rear axle 24 moves, the reel 73 and the second rotor 71 are rotated, and the second rotor 7
When the first insulating portion 104 is positioned on the conductive member 115 of the first rotor 70, the contact 118 is opened and the solenoid 5 is opened.
The energization to 7, 58 is cut off. Here, the actual tread width of the rear wheel 13 is not correctly fed back due to a maladjustment of the Bowden wire 72 or a failure of each part. If the energization is continued, the alarm device 121 operates continuously, so that the operator can recognize that the maintenance is required, and it is possible to prevent the relief valve 55 from continuing to operate for an abnormally long time, and to prevent malfunction. Reduction is also achieved.

As described above, by feeding back the actual tread width of the rear wheel 13 to the setting operation section 61, the required tread width can be easily and reliably set to the required tread width while being a simple operation. The actual tread width of the left and right rear wheels 13 can be displayed by the actual tread width display portion 62 provided around the left and right wheels. Further, even when the rear wheel 13 hits a rock, a curb or the like during traveling and the rear axle 24 is temporarily moved in the axial direction, the reel 73 and the second rotor 71 rotate accordingly. The contact 118 is connected, the hydraulic cylinder 36 is controlled to expand and contract so as to have the correct actual tread width set by the setting operation unit 61, and the reliability of the actual tread width indicated by the actual tread width display unit 62 can be secured. If the actual tread width is prevented from being displaced from the set tread width by this method, the circuit internal pressure becomes abnormally high as compared with the method in which the hydraulic cylinder 36 is hydraulically locked by confining the hydraulic oil using a check valve, and the Etc. are not damaged.

FIG. 14 shows a second embodiment of the electric control circuit. The difference from the first embodiment is that a predetermined time has elapsed from the start of energization of the solenoids 57 and 58 in place of the alarm device 121. An automatic power disconnection device 130 for forcibly disconnecting power to the solenoids 57 and 58 is provided. The device 130 includes a telescopic solenoid 57,5.
8 and the common ground 131, and the relay 132 is actuated for a predetermined time after the energization of one of the relays 57 and 58 and the relays 57 and 58 is started. And a timer 133 for connecting to the terminal 131. The time for operating the telescopic solenoids 57, 58 is set to, for example, 5 seconds.

According to the control circuit of the second embodiment, the continuous operation of the relief valve 55 due to the improper adjustment of the Bowden wire 72 can be reliably prevented. Note that an alarm device such as a lamp or a buzzer can be provided together with the timer 133. FIG. 15 shows a third embodiment of the electric control circuit. The difference from the first embodiment is that the alarm device 121 is not provided. I do.

FIGS. 16 and 17 show another embodiment of the setting operation section 61 and the like. The difference from the above embodiments is that the regulating member 65 is not provided and the setting operation section 61 is different. In that a large-diameter dial is adopted, and that the engagement pin 85 and the engagement hole 86 that regulate the rotation range of the first rotor 70 with respect to the second rotor 71 are not provided. The other configurations are the same, so the same reference numerals are given and the detailed description is omitted.

FIG. 18 shows the second embodiment of the present invention, and shows an example in which the microcomputer controls the telescopic solenoids 57 and 58. In addition, the first
The same components as those of the embodiment are denoted by the same reference numerals, and the detailed description is omitted. This tread adjusting device has a control unit 140 provided with a central processing unit (CPU). The control unit 140 includes a stroke sensor 141 provided on the left and right hydraulic cylinders 36, a buzzer 142 and left and right lamps 143 that constitute an alarm device, and an extension solenoid 57 and a compression solenoid 58 for the left and right rear axles 24. In addition to being connected, a pair of left and right volumes (not shown) provided in the casing 63 are connected. The control unit 140 includes a timer 133.

The setting operation section 61 is attached to the above-mentioned volume, and when the resistance value of the volume is changed by rotating each setting operation section 61, the expansion / contraction of the hydraulic cylinder 36 is controlled correspondingly. It is designed to energize the solenoids 57 and 58. Note that the actual tread width of each of the left and right rear wheels 13 is fed back to the setting operation unit 61 by an electric signal from the stroke sensor 141,
The extendable solenoids 57 and 58 are controlled so that the fed-back actual tread width signal and the volume of the setting operation unit 61 match.

FIG. 19 shows an example of a flowchart of a program for operating the control unit 140. In this flowchart, the left rear wheel 13 detected by the stroke sensor 141 attached to the left hydraulic cylinder 36
Is the first actual tread width LH, the tread width set by the setting operation section 61 on the left side of the casing 63 is the second actual tread width LS, and the right side detected by the stroke sensor 141 attached to the right hydraulic cylinder 36. The actual tread width of the rear wheel 13 is a first actual tread width RH, and the tread width set by the setting operation unit 61 on the right side of the casing 63 is a second actual tread width RS.

This program has an initialization program executed first when the engine is started. That is, when starting the engine, first, it is checked whether the first actual tread widths LH, RH of the left and right rear wheels 13 and the second actual tread widths LS, RS match, and if they match, the lamp 143 is turned on. If not, the corresponding lamp 143
Is controlled and the buzzer 142 is operated to notify the operator that the setting operation section 61 is being operated while the engine is stopped. When the operator operates the setting operation section 61 to match the first actual tread widths LH and RH with the second actual tread widths LS and RS, and the left and right lamps 143 are both turned on, the buzzer 142 is activated. Is stopped, and the initialization process ends.

By performing the initialization processing, even if the setting operation section 61 is operated accidentally while the engine is stopped, it is possible to prevent the tread width from being changed when the engine is started. In the above-described initialization processing, the hydraulic cylinder 36 is not operated until the first actual tread width and the second actual tread width match. However, if the difference is as small as about one pitch, the first embodiment will be described. The hydraulic cylinder 36 may be operated in the same manner as described above.

After the completion of the initialization process, the left and right hydraulic cylinders 36 are controlled by the right cylinder 3
6 is performed in priority. That is, first, the first rear wheel 13
Compare the actual tread width LH and the second actual tread width LS,
If they are different, the timer is initialized, and either the extension solenoid 57 or the compression solenoid 58 is excited, and when the widths LH and LS match, the solenoid 5 is turned off.
Power supply to 7 or 58 is stopped. If the two widths LH and LS do not match even after a predetermined time, for example, 5 seconds or more, an error process is performed because it is considered that the maintenance is defective. Error handling can be of any kind,
For example, the power supply to all the solenoids 57 and 58 is stopped, and the buzzer 142 notifies the operator.

When the first actual tread width LH of the left rear wheel 13 matches the second actual tread width LS, the right rear wheel 1
A similar process is performed for the first actual tread width RH and the second actual tread width RS. Since this process is the same as the above, detailed description is omitted, and is not shown in FIG. In the second embodiment, the first actual tread width LH,
A liquid crystal display device for displaying RH can be provided, and by providing such a display device, an initialization operation at the time of starting the engine can be easily performed.

The present invention is not limited to the above embodiments, but can be appropriately designed. For example, the setting operation unit 61
In addition to the dial type, it can be constituted by a knob that can be operated linearly. 20 and 21 show the front wheel 12
The left and right front axle cases 161 are provided on a front wheel differential case 160 provided at the front of the tractor vehicle body 11. This front axle case 161
The fixed case 162 includes a fixed case 162 fixed to the differential case 160, and a movable case 163 inserted in the fixed case 162 so as to be movable in the left-right axial direction.

A gear case 164 accommodating the final reduction gear is fixed to the outer end of the movable case 163, and a guide pin 165 projecting inward in the left-right direction is fixed. It is inserted and guided by a guide portion 166 provided on a side portion of the fixed case 162. A bracket 167 for fixing the movable case 163 is attached to the gear case 164. The bracket 167 is made of a long plate-shaped steel plate, and has a fixed case 162.
Is arranged on the upper surface side. The bracket 167 is provided with a plurality of mounting holes 168 in the left-right direction. Further, a tapered bolt hole is also provided on the upper surface of the fixed case 162, and the movable case 163 is fixed to the fixed case 162 by inserting and fastening the tapered bolt 171 by aligning one of the mounting holes 168 with the bolt hole. Fixed.

As described above, the detachable taper bolt 17
By using No. 1, even if the mounting hole 168 and the bolt hole are slightly displaced, these holes are forcibly matched by fastening the tapered bolt 171, so that the tread changing operation of the front wheel 12 can be facilitated and quick. Can be achieved. A front wheel case 174 is attached to the gear case 164 via a bracket 173 so as to be rotatable around a king pin 172, and the front wheel 12 is mounted on the case 174.

The tractor body 11 is provided with a hydraulic cylinder 175 of a power steering device. The hydraulic cylinder 175 includes a piston rod 176 projecting in both left and right directions.
Are connected to the bracket 173 via tie rods 177. The work of changing the tread of the front wheels 12 can be performed using the hydraulic cylinder 175 of the steering device.

[0065]

According to the present invention, the movement of the setting operation section for setting the tread width of the left and right wheels is restricted to only within a predetermined range based on the actual tread width. However, the tread is not operated to a position greatly deviated from the actual tread width, so that it is possible to prevent the tread from being greatly changed when the engine is started. further,
The tread can be changed easily and quickly by operating the setting operation unit, and even if the wheel hits an obstacle during running and is temporarily moved in the tread direction, the setting width by the setting operation unit is automatically adjusted. Can be restored.

Further, according to the present invention, since the hydraulic device for changing the tread width is electronically controlled, the operability can be made very good, and the actual tread width can be set to the set width at the start. In comparison, it is possible to prevent an unexpected operation when the setting operation unit is operated when the engine is stopped.

[Brief description of the drawings]

FIG. 1 is a plan view showing a casing according to a first embodiment of the present invention.

FIG. 2 is a side view of the casing.

FIG. 3 is a front view showing a right half of the casing in cross section.

FIG. 4 is a side sectional view of the casing.

FIG. 5 is a bottom view of the casing, and left reels are indicated by phantom lines.

FIG. 6 is a top view of the second rotor.

FIG. 7 is a bottom view of the first rotor.

FIG. 8 is a top view of the substrate.

FIG. 9 is a simplified perspective view showing a mounting structure of a stopper pin.

FIG. 10 is a perspective view showing a structure for attaching a Bowden wire to a rear axle case.

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

FIG. 12 is a hydraulic circuit diagram of a rear axle moving hydraulic device.

FIG. 13 is a circuit diagram showing a first embodiment of the electric control circuit.

FIG. 14 is a circuit diagram showing a second embodiment of the electric control circuit.

FIG. 15 is a circuit diagram showing a third embodiment of the electric control circuit.

FIG. 16 is a plan view showing another embodiment of the setting operation unit.

FIG. 17 is a front view showing the same embodiment, in which the right half is shown in cross section.

FIG. 18 is a simplified electric circuit diagram showing a second embodiment of the present invention.

FIG. 19 is a flowchart of a control program according to the second embodiment.

FIG. 20 is a simplified plan view showing a mounting structure of a front wheel.

FIG. 21 is a simplified rear view showing the same structure.

FIG. 22 is an overall side view of the tractor.

FIG. 23 is an overall plan view of the tractor.

[Explanation of symbols]

 Reference Signs List 10 Tractor 13 Wheel (rear wheel) 19 Driver's seat 36 Hydraulic device 61 Setting operation unit 63 Casing 71 Rotor (second rotor) 85 Pin 86 Slot (engagement hole) 140 Control unit RH Right wheel actual tread width RS setting operation Set tread width of right wheel by unit LH Actual tread width of left wheel LS Set tread width of left wheel by set operation unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akio Inamori 64 Ishizukita-cho, Sakai-shi, Osaka Inside Kubota Sakai Works

Claims (4)

[Claims] 1. Right and left wheels (13) of a tractor (10)
A setting operation unit (61) that can be manually operated to set the tread width of the stepless or multiple steps within a predetermined setting range;
A hydraulic device (36) for moving the wheels (13) in the tread direction in accordance with the set position of the operation unit (61), and the actual tread width of the right and left wheels (13) is fed back to the setting operation unit side. A tread adjusting device for a tractor, comprising: a restricting means for restricting a settable range of the setting operation section (61) only within a predetermined range based on the width. 2. Right and left rear wheels (13) of a tractor (10).
(63) provided with a setting dial (61) that can be rotated to set the tread width of the tread in a predetermined setting range in a stepless manner or in a plurality of steps, and according to a setting position of the dial (61). A hydraulic device (36) for moving the wheel (13) in the tread direction;
Are disposed near the driver's seat (19) of the tractor (10), and the casing (63) contains left and right rear wheels (1).
A rotor (71) interlocking with the movement in the tread direction of 3) is provided on the same axis as the dial (61), and regulates a relative rotation angle of the dial (61) with respect to the rotor (71) within a predetermined range. A tread adjusting device for a tractor, characterized by comprising means. The regulating means includes a circumferentially long hole (86) provided on the rotor (71) side and a pin (85) provided on the dial (61) side to engage with the long hole (86). 3. The tread adjusting device for a tractor according to claim 2, wherein: 4. Left and right wheels (13) of a tractor (10)
A setting operation unit (61) that can be manually operated to set the tread width of the stepless or multiple steps within a predetermined setting range;
A hydraulic device (3) for moving the wheels (13) in the tread direction
6) and a control unit (140) for electronically controlling the operation of the hydraulic device (36) according to the set width by the setting operation unit (61), and the control unit (140) includes left and right wheels (13). Feedback of the actual tread width of the control unit (1
40) are the actual tread widths (RH, LH) of the left and right wheels (13) at the time of starting and the set width (R) set by the setting operation section (61).
(T, S, LS).