JPH06104462B2 - Wheel steering method of tractor towing work machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic steering method for a working machine towed by a tractor to work.

TECHNICAL BACKGROUND In a field using a tractor and a working machine towed by the tractor, a land for changing the direction of the tractor and the working machine, that is, a vacant land called “pillow” is required at both ends of the ridge.

This pillow area makes it impossible to produce crops at all.

In terms of the control surface of the tractor, it is more convenient to have the area of the above-mentioned pillow, especially a large size, but from the viewpoint of production, the area should be as small as possible.

Therefore, efforts are being made to develop a work machine having a structure that allows the work machine to turn in a small radius in the above-mentioned pillow.

In a general vehicle, if the wheel base is large, the difference between the inner wheels of the rear wheels is also large, and therefore the turning radius of the rear wheels is much larger than the turning radius of the steered wheels.

In the case of a field work machine, since it is a articulated form towed by a tractor, if the work machine does not have a steering mechanism,
A wheelbase relationship is created between the rear wheels of the tractor and the wheels on the work implement side, and thus an inner ring difference based on the rut of the rear wheels of the tractor occurs. Therefore, in such a case, the tractor operator must perform steering with consideration for the rut of the rear wheel, because the rear wheel of the tractor is a basic curve running with respect to the working machine side wheel.

In such a situation, a large width of pillow is required.

Therefore, for the purpose of reducing the width of the pillow as much as possible and increasing the production amount, steering wheels can be provided to the wheels of the working machine in conjunction with the steering of the tractor that pulls the working machine. is there.

Techniques for imparting steerability to the wheels of an articulated vehicle in this way to reduce the turning radius also exist in trailers, etc., but these aims are achieved by simply reducing the turning radius. It is a thing.

The technology intended by the applicant is in the traveling locus of the work vehicle in the agricultural work machine, for example, the tractor comes out of the ridge from the ridge and at the end of the ridge, rotates in a direction orthogonal to the ridge direction, and, Even when the work implement is still in the ridge position, the wheels of the work implement are allowed to go straight along the ridge until it comes out to the pillow, and when entering the ridge section from the pillow again, The purpose is to enable the wheels of the work machine to run parallel to the ridges.

That is, these are to prevent the wheels of the tractor and the towed work machine from crushing the ridge for turning work even at the ridge end.

The basic technical idea is that when the wheels of a work vehicle can travel on the same track as the rudder of the rear wheels of the tractor, it is as if each wheel on the railroad track can travel on the same track. It has the same shape as the relationship with the wheels.

The steering mode of the wheels of the work vehicle that achieves the above purpose is such that, with the start of turning of the tractor, the wheels initially start at a gentle steering angle, gradually increase that angle, and suddenly increase at a certain point. The vehicle makes a turn, and the second half is a curved run that acts in a direction completely opposite to the first half. Therefore, the curved form of the work vehicle is made to turn with a small radius as a whole.

This is mechanically read out the displacement of the connection angle provided in the hitch part connecting the tractor and the work vehicle, and this is used as the operation command source for the hydraulic pressure switching operation via the electric transmission means. These steering instruction mechanisms are equipped on the work machine side,
The hydraulic power source is supplied from the tractor side.

In the working machine, the steering instruction mechanism is basically set so as to operate according to a certain set standard, but it is used by connecting to the tractor individually owned by the recipient side. Recipient tractors vary in vehicle type, model, and form, that is, horsepower, size, connection position, etc., depending on the manufacturer, and are generally used in order to match the function and purpose when using the work machine. Must make fine adjustments.

In addition, even in the case of the same beneficiary side and the same tractor, the wheel spacing of the work vehicle may be changed depending on the type of work every season.

That is, the size of the ridges varies depending on the type of agricultural product, and the number of ridges crossing the ridges varies.

In addition, the vehicle centerline of the work vehicle and the vehicle centerline of the tractor are not always aligned. (See FIG. 5)
In order to always match the one-sided track of the tractor with the one-sided track of the work vehicle, the track on the other side of the work machine with different vehicle width dimensions is in a state of inconsistency with the other side track of the tractor. Naturally it occurs. Therefore, the work vehicle is always located at the rear of the slant, and the slanted traction is in a proper connection form. The angle forming the oblique shape in the oblique traction also varies depending on the type of the tractor as described above, and it is necessary to finely adjust the steering instruction mechanism for each coupling work in order to obtain a proper shape. .

2. Description of the Related Art Conventionally, the traction angle between a tractor and a work machine is mechanically detected with respect to the wheels of a tractor-type work machine, and the resulting differential is used as a differential source of a piston rod in a cylinder to generate generated hydraulic pressure. The technique of using the steering power or steering oil pressure switching valve as an operation source is known in Japanese Laid-Open Patent Publications Nos. 50-121428 and 51-100541.

However, these mechanically detect the degree of displacement of the hitch angle as it is, and replace this with hydraulic pressure to provide a means for transmitting the displacement amount.

That is, the wheels of the towed vehicle are expected to have the same effect as the rear wheels of the tractor, resulting in an inner ring difference.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention enables a wheel of a working machine to run in parallel with a ridge until it comes out to a pillow, and when the ridge enters from a pillow to a ridge. In terms of the plan view of these tractors and work machines, the wheels of the work machine delay the turning steering more than the wheels of the tractor.
With respect to the work machine that has been towed and started to rotate, the direction of the wheels of the work machine is to steer in a direction opposite to the direction of rotation, and this is read mechanically from the hitch angle and once equipped properly. By controlling the hydraulic pressure via the electrically adjusted signal of the means described above, a more appropriate steering action can be obtained than the conventional steering means that connects the hydraulic pressure that directly operates the detected differential amount as the transmission means. The purpose is to do so.

Means for Solving the Problems The present invention is, as a means for achieving the above object, a work machine connected to a tractor and towed at a connecting portion at the time of bending to break a linear series state. A solenoid valve is operated by a solenoid valve that operates a solenoid valve by an electrical signal that is detected by a hitch angle sensor installed at the joint between a drawbar on the tractor side and a hitch on the working machine side. The steering action is performed by the movement of the pressure oil in the direction and the out-of-phase, and the steering action is linked to the steering action of the wheels of the work implement until the work implement shifts to the tractor in series, by the detection signal by the tire angle sensor, The continuity of the steering action is maintained by the circuit that controls the steering action.
When the tractor and the work implement return to the serial state, the automatic steering action is performed by linking the return steering action with the action of the tractor steering so that the work implement can go straight on the wheels of the steered work implement. It is made possible.

Embodiment An embodiment of the present invention will now be described with reference to the drawings. The positive side of the power source 1, the relay 2, the resistor 3, the diode 4, the automatic contact 6 of the push button switch 5, and the straight limit switch of the steering sensor 7. 8 is connected in series to form a circuit A.

A circuit B is formed by connecting the minus side of the power source 1, the minus side of the limit switch 8 for straight movement of the steering sensor 7, and the minus side of the solenoid valve 10 for steering. A limit switch 13 for left / right operation of the hitch angle sensor 12 and a contact 14 for left / right operation of the solenoid valve 10 are connected in parallel to a circuit C in series with the power source 1 and the relay 11.

In the circuit C, the two contacts of the snap switch 15 are connected in parallel with the relays 2 and 11.

A circuit D is formed by connecting the power source 1, the one contact 17 of the snap switch 15 and the limit switches 13 and 18 of the hitch angle sensor 12 in series.

Manual contact 19 of pushbutton switch 5 between power supply 1 and circuit C
To provide. The circuit E is formed by connecting the limit switch 18, the left and right operation limit switch 20 of the steering sensor 7, and the circuit C in series. Reference numeral 21 forms a circuit F by connecting in series a diode, the power source 1, the left and right push button switches 22 for hitching, and the left and right solenoid valves 9.

The circuit B, the circuit C, and the circuit F are connected through the diode 23.

Reference numeral 24 is a receiving plug, and 25 is a shell set.

Axle 32 and axle of work implement 31 towed by tractor 30
A hydraulic cylinder 34 is provided straddling a direction changing shaft 33 provided in parallel with 32, that is, the cylinder is attached to the axle 32, the piston rod is attached to the direction changing shaft 33, and the front and rear of the hydraulic cylinder 34 are provided. The oil pipes 37 and 38 of the solenoid valve 10 are connected and opened to the oil chambers 35 and 36, and the oil pipe 39 of the hydraulic package is connected and opened to the solenoid valve 10.

Further, a slide rod 41 covered with a dustproof case 40 is provided in parallel with the hydraulic cylinder 34, the dustproof case 40 is attached to the axle 32, the slide rod 41 is attached to the direction changing shaft 33, and the slide rod 41 goes straight to three places. , Right turn, left turn lock grooves 42, 43, 44 are engraved at regular intervals, and case 40
Install the limit switches 20,8,20 almost at the center of the
The tire angle sensor (see FIG. 3) is formed so that the limit switches 20, 8, 20 are opened and closed when the roller 45 is fitted into the lock grooves 42, 43, 44.

The straight lock groove 42 is shallow and has a width that can accommodate one roller 45, and the left and right lock grooves 43 and 44 are deep and have a width that allows two rollers 45 at the center and left or right, and the left and right limit switches. Is designed to close the circuit when entering the deep lock grooves 43 and 44.

The limit switches 13, 18, 13 for the hitch angle sensor 12 are attached to the hitch 46 provided at the front part of the working machine 31,
It is opened and closed by a drawbar interlocking cam 48 provided on a drawbar 47 pivotally attached to the front end of 46.

A roller 49 is attached to the front ends of the limit switches 13, 18, 13 at the tips. In contrast to this, a recess 50 is formed in one central place in a circular shape, a drawbar interlocking cam 48 is formed, the drawbar interlocking cam 48 is fixed to the drawbar 47, and the limit switches 13, 18 of the hitch angle sensor 12 are formed.
The roller 49 provided in 13 is abutted, and the limit switch 18 is fitted and abutted in the recess 50 so that the limit switch 13 is in the recess 50.
Keep it in contact with the outside.

22 is a push-button switch for ridge adjustment. A hydraulic package is connected to the solenoid valve 9 for ridge adjustment, and an oil pipe 52 of the solenoid valve 9 is connected and opened to a hydraulic cylinder 51 attached to a hitch portion. By pressing either of the push button switches 22, the solenoid valve 9
The oil is sent to the cylinder chamber, the piston rod is expanded and contracted, and the front part of the working machine is moved left and right to match the digging opening with the ridge.

First of all, the drawbar 47 is attached to the three-point link of the tractor 30 and the snap switch 15 is switched to fully automatic. After that, the work machine 31 is towed by the tractor 30 to work, and when the work is reversed and the next work is started, the tractor 30 When the steering wheel is turned to the left or to the right, the drawbar 47 rotates together with the tractor 30, so that the drawbar 47 rotates leftward or rightward relative to the hitch 46. The tractor interlocking cam 48 integrally attached to the drawbar 47 also rotates in the left or right direction together with the drawbar 47 with respect to the hitch 46, so that the limit switch 18 provided on the hitch 46 escapes from the recess of the drawbar interlocking cam 48. When the drawbar interlocking cam 48 rotates by a certain angle (for example, 45 degrees), either the left or right limit switch 13 enters the recess 50 and closes the contact, and either the left or right circuit of the solenoid valve 10 is closed and the valve is switched. Since the oil is pumped to the oil chambers 35 or 36 in the front and rear of the hydraulic cylinder 34, the rod of the cylinder 34 is expanded and contracted, and the direction changing shaft 33 moves leftward or rightward relative to the axle 32. Dustproof case 40 attached to
When the slide rod 41 inside moves to the left or right, the limit switch 8 moves to the thicker part of the slide rod 41 from the lock groove 42 for straight movement of the slide rod 41 and closes the contact, so that the relays 2 and 11 are Closing relay 11 is held, circuits B and C are held, solenoid valve 10
Is activated. Therefore, the solenoid valve 10 maintains the state as it is and pumps oil into the cylinder 34, so that the slide rod 41 continues to move in the left or right direction by the action of the rod of the cylinder 34, and the direction conversion shaft 33
Are moved and the wheels convert angles. During this operation, either the left or right limit switch 20 temporarily enters the lock groove 42 for straight movement of the slide rod 41.
Since 42 is shallow, the limit switch 20 passes without closing. Then, either left or right of the slide rod 41, which is deep and wide, has a lock groove 43 for left turn or right turn.
44 includes limit switch 8 and either left or right limit switch 20, and either left or right limit switch 20
However, the limit switch 8 turns off and the operation stops.

Then, when the handle is returned to the left or right, either the left or right limit switch 13 moves to a larger diameter than the recess 50 of the drawbar interlocking cam 48, and is turned off to a certain angle (for example, 0 to 20 degrees).
When rotated, the limit switch 18 fits into the recess 50 and closes the contacts. At this time, since either the left or right limit switch 20 is closed, either the left or right of the solenoid valve 10 is actuated, the oil is sent to either the oil chamber 36 or 35 of the front or rear of the cylinder 34, and the rod of the cylinder 34 is expanded or contracted. Also moves to the left or right and left, and when the limit switch 8 is closed, the relay 11 is closed and the circuit B and the circuit C are held, and the limit switch 8 is inserted in the lock groove 42 for straight traveling.
The relay 5 is held and the solenoid valve 10 is actuated to move the slide rod 41 to the left or the right until the switch enters, so that the wheel returns to the straight traveling state.

As an example, the case of turning the steering wheel to the left will be explained.
Since the drawbar 47 rotates integrally with the tractor 30,
The drawbar interlocking cam 48 that rotates to the left with respect to the hitch 46 and is integrally attached to the drawbar 47 also pivots to the left with the drawbar 47 with respect to the hitch 46, so the limit switch 18 provided on the hitch 46 is a drawbar interlocking cam. 48 recesses
When the drawbar interlocking cam 48 rotates at a constant angle (for example, an angle of 45 degrees) while exiting from 50, the right limit switch 13 enters the recess 50, and when the contact point is closed, the right circuit of the solenoid valve 10 is closed to operate. , The valve is switched so that the oil is pumped from the oil package to the oil chamber 36 of the hydraulic cylinder 34 and the rod of the cylinder 34 is extended to extend the axle.
Since the direction changing shaft 33 moves in the right direction with respect to 32, the slide rod 41 in the dustproof case 40 attached to the axle 32 and the direction changing shaft 33 moves in the right direction (left in FIG. 3). The limit switch 8 moves out of the straight lock groove 42 of the slide rod 41 and moves to the thick part of the slide rod 41 to close the contacts, so that the relays 2 and 11 are closed and the relay 11 is held. C is held and the solenoid valve 10 continues to operate. Therefore, the solenoid valve 10 maintains the state as it is, and the oil is pumped into the cylinder 34, so that the slide rod 41 continues to move in the right direction (left in FIG. 3) by the action of the rod of the cylinder 34. The direction changing shaft 33 is moved by the operation of the cylinder 34, and the angle of the wheel is changed to the right turn direction. During this operation, the left (right in FIG. 3) limit switch 20 enters the lock groove 42 for straight movement of the slide rod 41 once, but at this time the groove 42 for straight movement is shallow, so the limit switch 20 is closed. Pass without. Then, the limit switch 8 and the left limit switch 20 are inserted into the deep and wide leftward lock groove 44 of the slide rod 41, and the left limit switch 20 is closed but the limit switch 8 is OFF and the operation is stopped.

Then, when the steering wheel is returned to the right, the right limit switch 13 moves to a larger diameter than the recess 50 of the drawbar interlocking cam 48 and is turned off. When the steering wheel is rotated by a certain angle (for example, 0 to 20 degrees), the limit switch 18 is recessed. Mate to 50 and close the contacts. At this time, since the left limit switch 20 is closed, the left side of the solenoid valve 10 is actuated, the oil is sent to the oil chamber 35 of the cylinder 34, the rod of the cylinder 34 is contracted, and the slide lock 41 is also left (in FIG. 3). To the right), and when the limit switch is closed, the relay 11 is closed, the circuits B and C are held, the relay 11 is held until the limit switch 8 enters the lock groove 42 for straight advance, and the solenoid valve 10 operates. , The slide rod 41 is moved to the left (to the right in FIG. 3) so that the wheels return to the straight traveling state.

Since the present application can also perform the same action automatically or manually, to explain the action, if the snap switch 16 is automatically switched and either the left or right pushbutton switch 5 is closed, the circuits B and C are selected. Is closed, the solenoid valve 10 is actuated, and oil is sent from the hydraulic package to one of the oil chambers 35 and 36 of the hydraulic cylinder 34, and the piston rod protrudes from the hydraulic cylinder 34 and the direction change shaft 33
Slide rod 41 integrally pivoted to move leftward or rightward also protrudes from case 40, so roller 45 of limit switch 8 moves away from lock groove 42 for straight advance to a large diameter portion, Close the limit switch 8. Even if the push button switch 5 is released, the relay 11 and the limit switch 8 are closed, so that the circuits B and C are not opened, the solenoid valve 10 continues to operate, and the slide rod 41
Continues sliding and lock groove 43 for right turn or left turn or
When the limit switch 20 and the roller 45 of the 8 are completely engaged with the limit switch 44, the limit switch 8 is opened and the solenoid valve 10 stops its operation.

Therefore, the operation of the hydraulic cylinder 34 changes the direction of the wheel to the right turn or the left turn.

If the direction is changed, the vehicle turns, and when the vehicle goes straight after the turning, the pushbutton switch 5 for left turn or right turn is pressed to close the circuits B and C, operate the solenoid valve 10, and operate the oil chamber 36 or 35. The oil is sent to the piston rod, the piston rod projects into the hydraulic cylinder 34, and the slide rod 41 slides in either direction at the same time, so that the roller 45 of the limit switch 8 moves to the large diameter portion, and the limit switch is closed to turn on the relay 11. Even if the push button switch 5 is released, the circuits B and C are closed, so the solenoid valve 10 continues to operate until the roller 45 of the limit switch 8 fits into the lock groove 42 for straight movement. The piston rod moves to change the wheel in the straight direction.

When further turning left or right from straight ahead, if the push button switch 5 for left or right turn is pressed once again, the above operation is repeated and the wheels change direction to left or right turn.

By manually switching the snap switch 15, the circuits B and C are closed regardless of the relay 11 and the limit switch while the push button switch 5 for right turn or left turn is being pressed. It can operate and change the direction of the wheels.

As described above, although it acts in automatic and manual operation, this action is based on the distance formed between the rear wheel of the tractor 30 and the working machine 31, the so-called wheel base, and the rear wheel of the tractor 30. Axle position and drawbar
Although it is assumed that the gap distance to 47 is a set constant distance, in reality, the tractor 30 towing the work machine 31 is different from the tractor 30 in terms of its manufacturer, vehicle type, model, etc. The distance between the rear wheel and the draw bar is not strictly constant, so that the steering action of the wheels of the work machine 31 is not constant due to these distances.

Therefore, the rear wheel center position of the tractor 30 and the drawbar
Drawbar interlocking cam corresponding to the difference in planar distance to 47
48 and the shape of the slide rod 41, depending on the case, these drawbar interlocking cams 48, the limit switches 13,18,13 and 20,8,20 that come into contact with the slide rod 41 can be installed and fixed at the type and model of the tractor 30. By preparing correspondingly, the set steering operation of the wheels of the work machine 31 can be obtained.

According to the present invention, as described above, when the working machine 31 connected to the tractor 30 and towed is bent to break the linear series state, the drawbar 47 and the working machine 31 side on the tractor 30 side, which is the connecting portion, are connected. The hitch angle sensor 12 installed at the joint with the hitch 46 of No. 1 operates the solenoid valve 10 with an electric signal to detect the differential, and the wheels on the side of the working machine 31 are moved to the tractor.
The steering action is carried out by the movement of the pressure oil in a phase different from the curving direction of the tire 30, and the steering action is carried out by interlocking the wheels of the work implement 31 with the steering action until the work implement 31 shifts to the tractor 30 in series. By the detection signal from the angle sensor, the circuit that controls the steering action is maintained to keep the steering action, and
When the tractor 30 and the work implement 31 return to the in-series state, the steering operation for returning is automatically linked to the operation by the steering of the tractor 30 so that the work implement 31 can move straight on the wheels of the steered work implement 31. The steering action can be achieved.

As described above, the forward maneuver and the backward maneuver can be performed in the same manner.

Since the form of the tractor 31 is known when the working machine 31 is provided to the consumer, the working machine 31 does not need to be reworked by simply mounting the prepared compatible hitch angle sensor unit. It is possible to obtain the desired operation of steering the side wheels.

EFFECTS OF THE INVENTION The present invention is provided when a tractor towing a work machine comes out of a ridge from a ridge and starts turning steering to move to the next work ridge, and a displacement difference occurs in a connecting portion with the work machine. Although the wheels on the work implement side are steered with respect to the work implement, they exhibit a straight-ahead action that substantially follows the ridges, and the tractor and the work implement are in a straight line at the time when the wheels try to move out of the ridges into the meadow. By steering the tractor in a straight line, the wheels on the working machine side can be quickly returned so that they can go straight on the extension of the center line of the working machine, so that work with the tractor can be performed with a small pillow width. It has the effect of enabling turning with the machine.

In addition, even if the work implement behaves unintentionally due to a bad environment after the tractor starts turning, the tire angle sensor is provided with a holding circuit that maintains the steering relation between the work implement and its wheels. As a result, the desired operation can be maintained, and the present condition can be maintained until the steering cancellation command is automatically issued.

[Brief description of drawings]

FIG. 1 is a plan view of a working machine, FIG. 2 is a perspective view showing a relationship between an axle and a direction changing shaft, and FIG. 3 is a sectional view of a slide rod.
FIG. 4 is a circuit diagram of FIG. 4, FIG. 5 is a plan view of a state in which the tractor and the working machine are connected, and FIG. 7 …… Hitch angle sensor 9 …… Solenoid valve 10 …… Solenoid valve 12 …… Hitch angle sensor 30 …… Tractor 31 …… Work machine 34 …… Hydraulic cylinder 41 …… Slide rod 46 …… Hitch 47 …… Drawbar 48 ...... Drawbar interlocking cam

Continuation of the front page (56) Reference JP-A-51-100541 (JP, A) Actually open 50-134834 (JP, U) Actually open 50-121428 (JP, U)

Claims (1)

[Claims] 1. A work implement connected to a tractor is installed at a joint between a drawbar on the tractor side and a hitch on the work implement, which is a connecting part, when the work implement breaks straight in a straight line. The differential signal detected by the hitch angle sensor is actuated by operating the solenoid valve to operate the wheels on the working machine side with the movement of pressure oil in a phase different from the direction in which the tractor is moving. Until the working machine shifts to the in-line state with the tractor, the wheels of the working machine are interlocked with the steering action, and the detection signal by the tire angle sensor causes the circuit that controls the steering action to keep the steering action continued. And the work implement return to the in-series state, the return steering operation is automatically linked to the operation by the tractor steering so that the work implement can move straight on the wheels of the steered work implement. Wheel steering method of tractor towing the working machine, characterized by comprising as can be achieved steering action.