JPH05294251A - Steering lock pin protecting device in four-wheel steering vehicle - Google Patents

Abstract

PURPOSE:To protect the lock pin of a steering locking device by applying pres sure oil of lower relief pressure than normal relief pressure to lateral rear steering cylinders as long as the lock release of the steering locking device is not confirmed. CONSTITUTION:The lock release of a steering locking device 20 by a lock pin 27 is detected by a lock release confirming switch 48 provided at the lower part of an air cylinder 25. As long as a detection signal is not applied to a controller 51, the change-over valve 42 of a shut-off valve 40 provided at the by-pass passages 43, 44 of oil passages 35, 36 is switched into the opened state from the closed state so as to be switched to a low pressure relief valve 41. Lateral rear steering cylinders 10A, 10B are thereby operated with low pressure oil so as not to generate excessive stress around the lock pin 27 of the steering locking device 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a steering lock pin protection device for a four-wheel steering vehicle, and more particularly,
The present invention relates to a steering lock pin protection device for a four-wheel steering vehicle, in which either the rear steering or the front steering in the four-wheel steering vehicle can be locked by the steering lock device at a proper time.

[0002]

The present inventor has separately proposed that either the rear steering or the front steering in a conventional four-wheel steering vehicle can be timely locked by a lock pin of the steering lock device. Then, there is the one shown in the schematic explanatory view of FIG.

This is a wheel-wheel vehicle as a four-wheel steering vehicle in which power steering of a front wheel and a rear wheel can be operated simultaneously or separately.
Left rear wheel of a special vehicle such as a vehicle (refer to reference numeral "6A" in FIG. 2 showing an embodiment of the present invention. Incidentally, although not shown, the configuration and operation of the right rear wheel are substantially the same. Is provided at the end of the rear axle housing (same as 3) swingably by a king pin (same as 7) and extends from the knuckle (same as 8) of the left rear wheel (same as 6A). Knuckle arm 9 and left rear cylinder rod 11A of left rear steering cylinder 10A
The left end of the left rear steering cylinder 10A (right rear steering cylinder 10B).
(Approximately the same as above), oil is sent from the hydraulic pump 32 to either of the left and right oil chambers (FIG. 4) through the relief valve 32A, the rear steering control valve 33, etc., and the cylinder rod 11A is sent. The knuckle arm 9 is swung around the king pin (same as above), and at the same time, a right rear wheel (not shown) is swung around the king pin in the same manner as the left rear wheel (6A). Configure the power steering of the rear wheel.
Although not shown, the power steering of the front wheel also has substantially the same configuration.

In the power steering of the front wheel and the rear wheel of the special vehicle such as the wheel crane 1, the wheel crane 1 is run for a long distance, or It is not necessary to make a small turn around the wheel crane, and the rear steering lock device 20 is provided to improve the steering operability of the wheel crane 1 in a normal traveling state along a straight line and / or a gentle curve.
Is usually locked by the lock pin 27 so that the vehicle is in a state of traveling only by the front steering.

For this reason, the four wheels such as the wheel crane 1
In a wheel-power steering vehicle, the hydraulic pump 32
To the left chamber or the right chamber of the left and right rear steering cylinders 10A and 10B through the relief valve 32A, the rear steering control valve 32, the oil passages 35 and 36, and the left and right rear cylinder rods 11A, 11
B is returned to the neutral position (state of FIG. 3), and thereby the knuckle arm 9 connected to the left and right rear cylinder rods 11A and 11B by the pin 13 is returned to the neutral state of FIGS.
Through the knuckle 8, the left rear wheel 6A and the right rear wheel (6B) (not shown) are connected to the vehicle front-rear direction of the wheel crane (an arrow F in FIG. 2 showing an embodiment of the present invention).
Direction).

At this time, the knuckle 8 of the left rear wheel 6A
And a knuckle of a right rear wheel (not shown) are connected by a tie lot 15 and left and right rear wheels 6A, (6
B) rotates equiangularly around each kingpin 7.

Left rear wheel 6A and right rear wheel (6
2) in which the left and right rear steerings 10A and 10B are in the neutral position, the lock hole 9A of the knuckle arm 9 and the guide of the vehicle body base 2 are shown in FIG. The positions of the holes 22 in the vertical direction coincide with each other, and the lock hole 9A is located directly below the lock pin 27.

In this state, the air cylinder 25 as the lock cylinder of the rear steering lock device 20.
Compressed air is sent to the upper chamber (Fig. 4) to lower the cylinder rod 26, and the lock pin 27 at the end thereof is passed through the guide hole 22 of the vehicle body base 2 above the knuckle arm 9 and the knuckle arm. 9 is inserted into the lock hole 9A of the vehicle body 9 and is located below the knuckle arm 9 of the vehicle body base 2
The knuckle 8 of the left knuckle arm 9 is locked to the vehicle body base 2 by inserting it into the guide hole 22 (see FIG. 3), and therefore, the rotation of the left rear wheel 6A around the kingpin 7 is prevented. The rear steering of the left rear wheel 6A and the right rear wheel is locked, and the normal two-wheel steering traveling mode using only the front steering is blocked.

Compressed air is sent to the other side of the air cylinder 25 (the lower chamber in FIG. 4) to raise the cylinder rod 26, and the lock pin 2 is inserted through the lock hole 9A of the knuckle arm 9.
By pulling out 7, the knuckle arms 9 of the left and right rear wheels 6A, and hence the state of the lock device 20 for the rear steering, are released, and the rear steering of the rear wheel can be operated together with its front steering. By returning it, the front wheel and the rear wheel with small turns are used to prepare the four-wheel steering traveling mode.

[0010]

However, in the rear steering lock device in the power steering of the four-wheel steering vehicle as described above, for example, the left rear steering cylinder 10A (the right steering cylinder 1) is used.
For 0B, the pressure oil of the hydraulic pump 32 is supplied to either the left or right side (FIG. 4) via the rear steering control valve 33 and the oil passages 35 and 36. Further, by draining the oil to the tank 31, the left and right knuckle arms 9, 9 are pulled or pushed through the left and right cylinder rods 11A, 11B and rocked around the respective kingpins 7 to lock the knuckle arms 9. Hole 9
A, the guide hole 22 and the lock pin 27 of the vehicle body base 2
, The compressed air is sent to the upper chamber of the air cylinder 25, and the lock pin 27 at the end of the cylinder rod 26 is passed through the guide hole 22 of the vehicle body base 2 to lock the knuckle arm 9. The rear steering was locked by inserting it in the hole 9A.

Therefore, the oil is fed to the left and right rear steering cylinders 10A and 10B to rotate the rear wheel 6A around the king pin 7, and at the same time, the knuckle arm 9 is rotated to lock the lock hole 9A. The guide pin 22 of the vehicle body base 2 is accurately aligned with each other, and compressed air is sent to the air cylinder 25 while ensuring an accurate aligned state thereof, so that the lock pin 27 is inserted into the lock hole 9A of the knuckle arm 9. Although it can be inserted into the smooth and the rear steering can be locked in a smooth manner as needed,
By introducing the pressure oil to the left and right rear steering cylinders 10A, 10B, the left and right cylinder rods 11A, 1
If there is any error in the swing angle of the knuckle arm 9 around the king pin 7 that is swung via 1B, the lock hole 9A of the knuckle arm 9 and the guide hole 22 of the vehicle body base 2 are caused. The vertical position will be displaced.

As described above, the lock pin 27 and the knuckle luer
If the compressed air is sent to the upper chamber of the air cylinder 25 to lower the cylinder rod 26 in a state where the vertical position of the arm 9 is deviated from the lock hole 9A, the lock pin 27 causes the knuckle arm 9 to move. Misaligned lock hole 9A
Will be forced into.

When the positional deviation is large, not only is it difficult to insert the lock pin 27 into the lock hole 9A, but also the air cylinder 25 for operating the lock pin 27.
In addition, excessive stress is generated in the knuckle arm 9 and the left and right rear steering cylinders 10A, 10B, etc., so that the lock pin 27 does not enter the lock hole 9A of the knuckle arm 9 and does not go into the smooth. There is a risk that the lock pin 27 or the lock hole 9A may be damaged and that the lock pin 27, the air cylinder 25, the knuckle arm 9, the steering cylinders 10A, 10B, or the like may be damaged.

In particular, the lock pin 27 is a knuckle luer.
If it does not completely fit into the lock hole 9A of the cam 9, the correction is made by steering operation by supplying / discharging pressure oil to the left or right steering cylinders 10A, 10B, but if the operating direction is reversed, the lock pin 27 or There was a risk that stress would be generated in the peripheral mechanism and cause a failure.

In order to prevent damage to the lock pin 27 and the like as described above, the rear steering cylinder 1
Since it is necessary to perform the operation of aligning the lock holes 9A of the left and right knuckle arms 9 with the guide holes 22 of the vehicle body base 2 by 0A and 10B gently and carefully, it takes time, and moreover, the vehicle body base. There is a problem that it is not easy to ensure that the guide hole 22 of the screw 2 and the lock hole 9A of the knuckle arm 9 are accurately aligned with each other throughout the entire process of inserting the lock pin 27 into the lock hole 9A. there were.

The present invention has been made in view of the above problems in the prior art, and the lock pin of the steering lock device unlocks either the rear steering or the front steering of a four-wheel steering vehicle. When the lock release confirmation means provided around the lock pin or its operating means detects the lock release confirmation by the lock pin of the steering lock device, the detection signal causes a low release of the oil passage to the steering cylinder. -By allowing the relief pressure to be switched to the normal relief pressure by the switching means, the cylinder rod of the steering cylinder is moved with a low relief pressure oil during the operation of the lock pin of the steering lock device,
An object of the present invention is to provide a protection device for a steering lock pin in a four-wheel steering vehicle that can solve the above problems by smoothly inserting the lock pin into a lock hole of a knuckle arm and locking the lock pin.

[0017]

In order to solve the above-mentioned problems of the conventional example, the present invention enables either the rear steering or the front steering of a four-wheel steering vehicle to be locked by a lock pin at a proper time. A lock release confirmation means by the lock pin of the lock device is provided around the lock pin of the steering lock device or an operating means of the lock pin, and a rear steering cylinder or a front steering wheel is provided by a lock release confirmation signal detected by the lock release confirmation device. Oil pressure to the cylinder
A switching means for switching from a low relief pressure to a normal relief pressure is provided, and a rear wheel and / or a front wheel provided at the end of the rear axle and / or the front axle via a king pin. Knuckle arm,
The rear axle and / or the axle housing of the front axle or the gear casings thereof are connected by a rear steering cylinder and / or a front steering cylinder, and the rear wheel and / or the front wheel are arranged in the longitudinal direction of the vehicle body. In the state in which the knuckle arm is oriented, a lock pin capable of appearing and retracting in the lock hole of the knuckle arm is provided in the vehicle body base, and either the rear steering or the front steering is locked by the lock pin. In a steering lock device for a four-wheel steering vehicle,
A lock release confirmation means for the steering lock device by the lock pin is provided around the lock pin or its operating means, and a lock release confirmation signal detected by the lock release confirmation means is applied to the rear steering cylinder or the front steering cylinder. A switching means is provided for switching the oil passage pressure from the low relief pressure to the normal relief pressure.

(Operation) Since the present invention has the above-mentioned structure, either the rear steering or the front steering is locked by the lock pin of the locking device, and only the front steering or the rear steering is provided. Regarding a four-wheel steering vehicle that can be switched to a normal two-wheel steering traveling system,
The lock release by the lock pin of the steering lock device for either the rear steering or the front steering is detected by the lock release confirmation means provided around the lock pin or the operation means thereof, and by this lock release confirmation detection signal, Releasing the oil passage to the rear steering cylinder or the front steering cylinder
The relief pressure can be switched from a low relief pressure to a normal relief pressure, and when the lock pin is moved, low relief pressure oil is sent to the rear steering cylinder or the front steering cylinder, With the same low relief pressure oil, the rear wheel or front wheel is rotated around their kingpins, and the lock pin of the rear steering or front steering lock device is inserted into the lock hole of the knuckle arm without difficulty. And lock.

Further, a knuckle arm of the rear wheel and / or the front wheel provided at the end of the rear axle and / or the front axle via a kingpin, and an axle housing of the rear axle and / or the front axle or around a gear case. A bypass provided with a switching valve for switching a relief pressure to a low pressure relief valve is provided in an oil passage for supplying pressure oil to the rear steering cylinder and / or the front steerer, and the switching valve of the bypass is locked by the lock valve. When the lock pin of the device or its operating means is provided, it is closed by the lock release confirmation detection signal by the lock release confirmation means to switch to the normal relief pressure, and when there is no lock release confirmation signal, The rear steering cylinder or the front steering cylinder Pressure oil is used as a low relief pressure to move the knuckle arm of the rear wheel or front wheel with low pressure oil, and the lock pin is inserted into the lock hole of the knuckle arm without difficulty, resulting in smoothness. Lock the steering.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lock pin protection device in a steering device for a special vehicle according to the present invention will be described below with reference to FIGS. Incidentally, the same names and the same reference numerals are used for the portions common to the conventional example shown in FIG.

FIG. 1 is a schematic perspective view of the essential portion showing an embodiment of a steering lock pin protection device in a four-wheel steering vehicle according to the present invention, together with its hydraulic circuit.
FIG. 2 is a schematic plan view of the rear steering lock device, and FIG. 3 shows a main part of the rear steering lock device.
FIG. 3 is a schematic side surface explanatory diagram viewed from a direction of an arrow G in FIG. 2 (a rear side of the vehicle).

1 to 3, 1 is a wheel crane as a four-wheel steering vehicle, 2 is a vehicle body base of the wheel crane 1, 3 is a rear axle, 4 is a rear axle housing, and 5 is a rear axle. 3 gear case,
6A is a left rear wheel, 7 is a king pin that installs the left rear wheel 6A at the end of the rear axle 3, and 8 is a rear wheel.
6A knuckle, 9 knuckle arm, 10A left rear steering cylinder, 11A left steering cylinder 10A left cylinder rod, 12 pin for rotatably connecting the steering cylinder 10 and the gear gear 5,
13 is a left rear cylinder rod 11A and a knuckle arm 9
It is a pin that rotatably connects and.

In the four-wheel steering vehicle referred to in this specification, one tire 6A as shown in FIG. 2 is provided through the kingpin 7 at the ends of the rear axle 3 and the front axle (not shown). , Outside the so-called four-wheel steering vehicle, and at the ends of the rear axle 3 and the front axle via their kingpins 7, 2
It goes without saying that a configuration in which either one of the rear steering and the front steering of this embodiment can be alternately locked, such as a configuration in which individual tires are provided, is also applicable.

Reference numeral 15 is a tie lot for connecting the knuckle arms 9, 9 of the left and right rear wheels 6A, 6B, 20 is a steering lock device, 22 is a guide hole of a lock pin 27, 25 is an air cylinder as a lock cylinder, 26
Is a cylinder rod of an air cylinder, 28 is a vehicle base 2
The columns 29, which are erected upright, are links, and the cylinder rod 2 of the air cylinder 25 is provided at both ends of the link 29.
The upper end of 6 and the upper end of the lock pin 27 are rotatably connected. Reference numeral 30 denotes a support shaft that rotatably supports the central portion of the lever 29 on the support column 28.

Reference numeral 31 is a tank, 32 is a pump, 33 is a rear steering control valve, 35 and 36 are oil passages for supplying and discharging pressure oil to the left and right rear steering cylinders 10A and 10B, and 32A is oil passages 35 and 36. It is a relief valve that sets the normal hydraulic pressure. The above configuration is substantially the same as the steering lock device in the four-wheel steering vehicle shown in FIG. 4 according to another proposal of the present inventor.

Reference numeral 40 is a shutoff valve, 41 is a low pressure relief valve, 42 is a switching valve, and 43 and 44 are hydraulic pressures 3.
5, 36 bypasses, 45, 46 bypasses 43, 44
A check valve 47 is provided on the lock check switch 47, and the lock check switch 47 is provided on the top of the air cylinder 25 (FIGS. 1 and 3). A lock pin 27 that descends via a link 29 supported by a column 28
, The lock hole 9A of the knuckle arm 9 and the vehicle body base 2
The lock confirmation signal is transmitted by being turned on by being inserted into the guide hole 22 (on the lower side in FIG. 3).

48 is the bottom of the air cylinder 25 (see FIG. 1,
With the lock release confirmation switch provided in 3), the cylinder pin 26 of the air cylinder 25 is lowered to lock the lock pin 2
After being pulled out from the lock hole 9A of the knuckle arm 9, the switch 7 is turned on and a lock release confirmation signal is transmitted.

The lock confirmation switch 47 and the lock release confirmation switch 48 are provided at the top and bottom around the air cylinder 25 as shown in FIGS. 1 and 3.
Although not shown, the structure is provided around the lock pin 27 to directly detect the ascending / descending position of the lock pin 27 for confirmation, or the support column 2
8 is provided around the support shaft 30 and the rotation angle of the link 29 rotatably supported by the support shaft 30 in the clockwise or counterclockwise direction is detected to confirm the lock by the lock pin 27. Alternatively, the lock pin 27 can be pulled out to confirm the release of the lock.

Reference numeral 49 is a signal line for a lock confirmation signal transmitted from the lock confirmation switch 47, 50 is a signal line for a lock release confirmation signal transmitted from the lock release confirmation switch 48, 51 is a controller, and 52 is a pressure reduction command signal. It is a line.

(Operation of the Embodiment) (Release of Rear Steering Lock Device) When compressed air is introduced into the upper chamber of the air cylinder 25 as a lock cylinder and the cylinder rod 26 is lowered, the upper end of the cylinder rod 26 is lifted. The link 29 pivotally attached to the shaft swings around the support shaft 30 of the column 28, and the lock pin 27 connected to the other end of the link 29 rises to guide the vehicle body base 2 (lower side in FIG. 3). Hole 22, lock hole 9A of knuckle arm 9
3 is pulled out from the position indicated by the chain line 27A in FIG. 3 to be in the position of the solid line position 27 in FIGS. 1 and 3, and the locked state by the lock pin 27 of the rear steering lock device 20 is released.

When the rear steering lock device 20 is in the unlocked state, the rear steering control valve 33 is lowered, for example, by operating a steering wheel (not shown) of the four-wheel steering vehicle, and pressure oil from the pump 32 is transferred to the oil passage 36. Oil is sent to the right chambers (Fig. 1) of the left and right rear steering cylinders 10A, 10B via the cylinders to move the cylinder rods 11A, 11B to the left side, and the pin 13
The left rear wheel 6A along with the knuckle arm 9 and the knuckle 8 is rotated clockwise around the kingpin 7 (Fig. 2).
Turn to.

Similarly, the cylinder rod 11B of the right rear steering cylinder 10B also moves to the left to rotate the right rear wheel clockwise around its kingpin. At this time, since the knuckles 8, 8 of the left and right rear wheels 6A, 6B are connected by the tie-lot 15, the left and right rear wheels 6A, 6B turn equiangularly around their kingpins to perform the required rear steering operation. Is done. The front steering is also operated in the same manner, and the normal four-wheel steering traveling mode is set.

(Rear Steering Lock) Further, compressed air is introduced into the lower chamber of the air cylinder 25 to lock the lock pin 2.
In the state where 7 is raised to the neutral position, the cylinder rods 11A and 11B of the left and right rear steering cylinders 10A and 10B are set to the neutral position, and the lock pin 9A of the knuckle arm 9 is guided to the guide hole 22. 27, the compressed air is introduced into the lower chamber of the air cylinder 25, the lock pin 27 is lowered together with the cylinder rod 26, and the lock pin 27 is inserted into the lock hole 9A to lock the rear steering device 20. Wheel Cray
1 to normal 2 by its front steering only
Prepare for wheel steering.

The above operation has been proposed by the present inventor, and either the rear steering or the front steering in the same four-wheel steering vehicle as the present invention shown in FIG. 4 is locked by the lock pin 27. The procedure is substantially the same as the two-wheel steering traveling posture and the lock state by the lock pin 27 is released to the four-wheel steering traveling posture. Proximity switch)
47 and lock release confirmation switch (proximity switch) 48
The lock confirmation and lock release confirmation signals detected by the both confirmation switches 47 and 48 are applied to the controller 51 through the lock confirmation signal line 49 and the lock release confirmation signal line 50.

When the lock release confirmation signal is not applied to the controller 51, a pressure reduction command signal is transmitted from the controller 51, and the switching valve 42 of the shutoff valve 40 is connected via the pressure reduction command signal line 52. Oil passages 35, 3 provided with a relief valve (not shown) having a normal relief pressure by moving from the closed position in FIG. 1 to the right to switch to the open position.
The bypasses 43 and 44 connected to the low pressure relief valve 4
1 to the tank 31.

As a result, the oil pressure in the oil passages 35, 36 becomes a low pressure set by the low pressure relief valve 41, and the working oil pressure to the left and right rear steering cylinders 10A, 10B becomes a low pressure, and is passed through the left and right cylinder rods 11A, 11B. The operating force of the knuckle arm 9 of the left and right rear wheels 6A and 6B operated by
Is driven around the king pin 7 with a small torque, and therefore, the lock pin 27 causes the lock hole 9A of the knuckle arm 9 and the guide hole 22 of the vehicle body base 2 (lower side in FIG. 2).
It is inserted without difficulty in.

When the cylinder rod 26 of the air cylinder 25 is raised, the lock pin 27 is lowered via the link 29 and inserted into the lock hole 9A of the knuckle arm 9, and the lock confirmation switch 47 is turned on, thereby locking the lock. The confirmation signal is transmitted to the controller 51 via the lock confirmation signal line 49, the lowering of the lock pin 27 is stopped, and the lock state by the lock pin 27 of the rear steering device 20 is secured.

(Rear steering lock release)
The cylinder rod 26 of the air cylinder 25 is lowered and the link 29 is rotated clockwise around the support shaft 30 to move the lock pin 27 from the position of the chain double-dashed line in the lock hole 9A of the knuckle arm 9 (FIG. 3). When it is pulled out and raised to the position shown by the solid line in FIG. 3, the lock release confirmation switch 48 is turned on.

The lock release confirmation signal transmitted by turning on the lock release confirmation switch 48 is transmitted to the controller 51 via the lock release confirmation signal line 49.
Low voltage signal line 52 transmitted from the same controller 51
Is cut off, the switching valve 42 of the shutoff valve 40 is moved leftward by the spring to the cutoff position shown in FIG. 1, and the bypasses 43 and 44 are closed to close the oil passage 35.
The hydraulic pressure of 36 returns to a higher (predetermined) relief pressure, and the left and right rear steering cylinders 10A, 10B
The high-pressure oil is sent to the rear steering device 20 so that the power steering operation can be performed by the rear steering device 20 and the normal four-wheel power steering operation is resumed.

In the above description, the cylinder rod 26 of the air cylinder 25 and the lock pin 27 are supported on the top of the support column 28 on the vehicle body base 2 as the operating means of the lock pin 27 of the rear steering lock device 20. The example in which the link 29 is rotatably connected to both ends of the link 29 pivotally supported by the shaft 30 has been described. However, as long as a sufficient space can be secured around the top of the lock pin 27, the lock by the air cylinder 25 is performed. As the driving means of the pin 27, the air cylinder 25 is arranged on the extension line of the top of the lock pin 27, and the air cylinder 25 is attached to a proper position on the vehicle body base 2 (not shown). You can

Further, the air cylinder 25 as the lock cylinder may be constructed as a hydraulic cylinder, which is not shown.

The lock pin protection device in the steering lock device of the four-wheel steering vehicle can be implemented as the steering lock device 20 of the rear wheel 6A as in the above-described embodiment, and the steering lock device of the front wheel. Can be similarly implemented.

Although the wheel crane 1 is mentioned as an example of the four-wheel steering vehicle in the above description, the steering lock pin protection device in the four-wheel steering vehicle of the present invention is either a rear steering wheel or a front steering wheel. As long as it is a four-wheel steering vehicle having a configuration in which one of them is alternately locked by the steering lock device, it can be implemented as a protection device for a lock pin of a steering lock device of a special vehicle such as a power shovel.

[0044]

Since the present invention has the above-mentioned structure and operates, the following effects can be obtained.

(1) A lock release confirming means provided around the lock pin or the operating means of the lock pin for the motion state of the lock pin of the steering lock device for either the rear steering or the front steering of a four-wheel steering vehicle. Is not detected, that is, unless the lock release confirmation switch is turned on, the hydraulic pressure sent to the steering cylinder is switched to a low pressure. Therefore, the lock pin of the steering lock device, the lock cylinder of the lock pin, and them There is no undue force applied to the part related to the steering wheel, and the lock pin of the steering lock device and the periphery of the lock pin are protected.

(2) If the left or right steering lock pin does not completely fit into the lock hole of the left or right knuckle arm, pressure oil is supplied to or discharged from the left or right steering cylinder. It is necessary to correct by steering operation. In such a case, however, in the present invention, the hydraulic pressure sent to the steering cylinder is inevitable as long as the lock pins of the left and right steering lock devices are being operated normally. However, even if the steering direction is reversed in this state, the lock arm is driven by low-pressure oil, and therefore, the lock pin and its peripheral mechanism are not stressed. There is no fear of causing.

(3) As long as the lock pin of the steering lock device in the same type of conventional four-wheel steering vehicle is in motion (the lock release confirmation switch is not turned on), the hydraulic pressure applied to the lock cylinder is the normal release. Since it is lower than the pressure, the force applied to the lock pin is reduced compared to the conventional example, and there is no fear of causing excessive stress in the peripheral mechanism of the lock pin, and the operability of the lock pin is improved. To do.

(4) As long as the lock pin of the steering lock device in a four-wheel steering lock vehicle is in motion, the oil pressure to the steering cylinder is switched to a pressure lower than the normal relief pressure, so that the oil pressure in the oil Containment pressure in the circuit is reduced.

[Brief description of drawings]

FIG. 1 is a schematic perspective explanatory view of a main part of an embodiment of a steering lock pin protection device in a four-wheel steering vehicle according to the present invention.

FIG. 2 is a schematic plan view of a main part of the steering lock pin protection device.

FIG. 3 is a schematic side view of a main part of the steering lock pin protection device.

FIG. 4 is a schematic perspective explanatory view of a steering lock device in another four-wheel steering device proposed by the present inventor.

[Explanation of symbols]

1 ... Wheel crane (4-wheel steering vehicle) 2 ... Body base 3 ... Rear axle 4 ... Rear axle housing 5 ... Gear case 6A ... Left rear wheel 7 ... King pin 9 ... Knuckle arm 9A ... Lock hole 10A, 10B ... Left and right rear steering cylinders 11A, 11B ... Left and right rear cylinder rods 20 ... Lock device 22 ... Guide hole 25 ... Air cylinder (Lock cylinder ) 26 ... Cylinder rod 27 ... Lock pin 29 ... Link 31 ... Tank 32 ... Pump 33 ... Steering control valve 35, 36 ... Oil passage 40 ... Shut-off valve 41 ... Low pressure release Valve 42 ... Switching valve 43,44 ... Bypass 45,46 ... Check valve 47 ... Lock confirmation switch (Locking check means) 48 ...... lock release confirmation switch (lock release confirming means) 49 ...... lock acknowledge signal line 50 ...... lock release confirmation No. lines 51 ...... controller - La 52 ...... pressurization command signal line

Claims (3)

[Claims] 1. A lock pin of a steering lock device that locks either one of a rear steering and a front steering of a four-wheel steering vehicle with a lock pin at a proper time, or a lock device for locking the lock device around an operating means of the lock pin. Lock release confirmation means by means of a pin is provided, and the oil passage pressure to the rear steering cylinder or the front steering cylinder is switched from the low relief pressure to the normal relief pressure by the lock release confirmation signal detected by the lock release confirmation means. A protection device for a steering lock pin in a four-wheel steering vehicle, comprising a switching means. 2. A rear wheel and / or a knuckle arm of the front wheel provided at the ends of the rear axle and / or the front axle via a kingpin, an axle housing of the rear axle and / or the front axle, or gear casings thereof. A rear steering cylinder and / or a front steering cylinder are used to connect the surroundings of the vehicle to the vehicle body base in a state in which the rear wheel and / or the front wheel are oriented in the vehicle longitudinal direction of the vehicle. Providing a lock pin that can appear and disappear in the lock hole of the knuckle arm through the hole,
In a steering lock device for a four-wheel steering vehicle that locks either one of the rear steering and the front steering with the lock pin, a lock release confirmation of the steering lock device by the lock pin is provided around the lock pin or its operating means. And means for switching the oil passage pressure to the rear steering cylinder or the front steering cylinder from the low relief pressure to the normal relief pressure in response to the lock release confirmation signal detected by the lock release confirmation means. A steering lock pin protection device for a four-wheel steering vehicle. 3. A rear wheel is provided at a rear axle end of a four-wheel steering vehicle via a kingpin, a knuckle arm extending from the knuckle of the rear wheel, and a rear axle housing of the rear axle or a gear case thereof.
The knuckle rail extending from the rear wheel facing the front-rear direction of the vehicle body is connected to the vehicle body by a rear steering cylinder, and a lock pin is connected to the vehicle body base through a guide hole of the vehicle body base of the vehicle. In a rear steering lock device for a four-wheel steering vehicle provided so as to be insertable into a lock hole of a cylinder, a lock confirmation switch and a lock release confirmation switch by a lock pin connected to a cylinder rod of the lock pin are provided around the lock cylinder. Each switch is provided, and when the lock release confirmation switch is turned on, the switching valve of the shut-off valve provided in the bypass of the oil passage to the rear steering cylinder is switched from the open state connected to the tank via the low pressure relief valve to the closed state. 4-wheel steer characterized by being configured to obtain Protection device of the steering lock pin in the ring vehicle.