JPH0139624Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a front wheel steering lock device for a four-wheel drive vehicle such as a truck crane, which is configured to enable front wheel steering and rear wheel steering.

In the above-mentioned four-wheel-drive vehicle, the front wheels are steered when driving at high speeds on roads, but when moving around the site, the front and rear wheels may be set in opposite phases, or in the same phase for width alignment. This is what we are doing.

However, especially when front and rear wheel antiphase steering is used, the turning radius of the vehicle becomes very small.
There is a risk of falling when driving at high speeds.

For this reason, front wheel steering and rear wheel steering are configured to be used by selectively switching between them, but in the case of front wheel steering, the rear wheels are disconnected from the steering mechanism, so they do not move freely. There is a danger that the vehicle will meander, and in this case it is necessary to manually turn the rear wheels in the straight direction and lock them.

The present invention has been proposed as a device that can easily and reliably lock the rear wheels when steering the front wheels, and can also improve the degree of freedom in steering the vehicle until the front wheels are locked. It is.

Embodiments of the present invention will be described based on the drawings.

In the figure, reference numeral 1 denotes an electromagnetic steering switching valve, and this steering switching valve 1 has a neutral position a, a front and rear wheel reverse phase steering operating position b, and a crab steering operating position c. It is always biased by a spring to the neutral position a, and can be switched by selectively energizing both electromagnetic operating parts (solenoids). This steering switching valve 1 has a hydraulic power source 4 and hydraulic cylinders 5, 5 for steering the front wheels connected to its primary side via a steering valve 3 whose oil amount is adjusted by a steering handle 2. Further, hydraulic cylinders 6, 6 for steering the rear wheels are connected to the secondary side. Both electromagnetic actuating parts of this steering switching valve 1 are connected to a steering mode switch 7, and by switching this switch 7 to a neutral terminal 7a, the steering switching valve 1 becomes a neutral position a, and the front wheels are steered. , and the switch 7 is connected to the front and rear wheel reverse phase steering terminal 7b.
By switching the steering control valve 1 to the front and rear wheel opposite phase steering operation position b, the front and rear wheels are in reverse phase steering.Furthermore, by similarly switching the switch 7 to the front and rear wheel same phase steering terminal 7c, The front and rear wheels are steered in the same phase.

Reference numeral 8 denotes a locking metal fitting. This metal fitting 8 is fixed to an operating member on the rear wheel steering device side, such as a knuckle arm, and is adapted to operate together with the knuckle arm when the rear wheel is steered. This metal fitting 8 is provided with a lock hole 9. On the other hand, 10 is a lock pin provided slidably on the axle side, and this lock pin 1
0 is such that the lock fitting 8 engages with the lock hole 9 when the lock fitting 8 is in a neutral state, that is, when the rear wheels are traveling straight. Reference numeral 11 denotes a cylinder that operates this lock pin 10, and this cylinder 11 is connected to a hydraulic power source via a lock operation valve 12. The lock operation valve 12 is of an electromagnetic type, and is switched by selectively energizing a lock solenoid 12a and a release solenoid 12b.

Reference numerals 13, 14a, and 14b are one lock confirmation switch and two release confirmation switches provided near the lock pin 10, and 15 is a center detection switch provided near the lock fitting 8. 16 is an ON/OFF type manual rear wheel steering switch, one terminal of which is connected to a power source 17.

Reference numerals 18a to 18e indicate first to fifth relays having the same configuration, and each relay includes an excitation coil 19a to 19e and a normally open switch 20a to 20e that is turned on by the excitation coil.

The human power side of the coil 19a of the first relay 18a is connected to the output side terminal of the rear wheel steering switch 16.
Also, the other side is grounded. Also this relay 1
The input terminal of 8a is connected to the power supply 17, and the ON side terminal is connected to the input terminal of the second relay 18b.
The OFF side terminal is connected to the input terminal of the third relay 18c and the input side of the center detection switch 15. The input side of the coil 19b of the second relay 18b is connected to the input side of this relay 18b, and the ground side is grounded via the first release confirmation switch 14a. Also, this second relay 18b
The ON side terminal is connected to the release solenoid 12b of the lock operation valve 12, and the OFF side terminal is connected to the first indicator 21.

As described above, the input terminal of the third relay 18c is connected to the OFF side terminal of the first relay 18a, and the ON side terminal is connected to the fourth relay 18a.
It is connected to the input terminal of d. Also coil 19
The input side of c is connected to the ON terminal of the center detection switch 15.

The ON side terminal of the fourth relay 18d is connected to the lock solenoid 12a of the lock operation valve 12, the input side of the coil 19e of the fifth relay 18e, and the second indicator 22, and the coil 19d
The input side of is connected to the power supply via a lock confirmation switch 13.

The input terminal of the fifth relay 18e is connected to the power supply and
The ON side terminals are each connected to the first indicator 21, and the input side of the coil 19e is connected to the ON side terminal of the fourth relay 18d and the second indicator 22 as described above.

The operation of the above configuration will be explained below.

(1) Change the rear wheel steering from the released state to the rear wheel locked state. Note that the drawing shows the state in which the lock is completed.

Turn off the rear wheel steering switch 16. In this way, the input side of the center detection switch 15 is energized through the OFF side terminal of the first relay 18a. Second release confirmation switch 14 before locking
Since the switch 14b is closed, the steering mode switch 7 is connected to the power source via this switch 14b. Therefore, in this state, by putting the steering mode switch 7 into the front and rear wheels opposite phase steering terminal 7b or the front and rear wheels same phase steering terminal 7c and operating the steering, the rear wheels are steered together with the front wheels.

When the rear wheels are steered straight and the center detection switch 15 is closed, the third relay 18c is turned on. Note that since the lock confirmation switch 13 is closed before locking, the fourth relay 18d is turned on. Therefore, when the third relay 18c is turned on, the locking solenoid 12a of the locking operation valve 12 is energized via the fourth relay 18d, the valve 12 is in the locking position, and the locking pin 10 performs a locking operation. At the same time as the lock is completed, the lock confirmation switch 13 is opened and the fourth relay 18d is activated.
OFF, the lock operation valve 12 returns to neutral,
Lock pin 10 remains locked. At this time, the second indicator 22 lights up during the locking operation and goes out when the locking is completed.

(2) Change the rear wheel steering from the locked state to the released state.

Turn on rear wheel steering switch 16. This turns on the first and second relays 18a and 18b.
Then, the release solenoid 12b of the lock operation valve 12 is energized and becomes the release position, and the lock pin 10 is released. Lock pin 1
When 0 is released, the first release confirmation switch 1
4a is open and the second relay 18b is OFF.
Then, the second release confirmation switch 14b is closed, and the steering mode can be selected by the steering mode switch 7. Said second relay 1
8b turns off, the lock operation valve 12 returns to neutral, and the unlocked state is maintained. The first indicator 21 goes out when the lock is locked, and lights up during the lock or when the lock is released.

Since the present invention is as described above, the lock operation can be performed easily. In addition, the lock operation is performed only when the rear wheels are in a straight-ahead state, and since the rear wheels are locked when the rear wheels are operated, even after the rear wheel steering switch 16 is turned OFF, the steering will not continue until the pin is completely in the lock position. Since electricity is supplied to the mode switch via the lock release confirmation switch 14b, the steering mode can be selected from front and rear wheel reverse phase steering mode or front and rear wheel same phase mode, and therefore rear wheel steering operation is possible. Even if the rear wheels are not in a straight-line direction and the pin gets stuck on the way, centering is possible and locking is easy. Further, according to the present invention, by switching between the rear wheel steering switch 16 and the steering mode switch 7, it is possible to perform only the front wheel steering operation or both the front wheel steering operation and the rear wheel steering operation. Therefore, by switching both switches 7 and 16, the turning radius can be reduced by steering both the front wheels and the rear wheels regardless of the size of the front wheel steering angle, making it easy to use at narrow construction sites. It is possible to improve the running workability of the machine.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing an embodiment of the present invention. 1 is a steering switching valve, 3 is a steering valve, 5 and 6 are hydraulic cylinders, 7 is a steering mode switch, 10 is a lock pin, 11 is a cylinder, 12 is a lock operation valve, 1
2a and 12b are solenoids, 13 is a lock confirmation switch, 14 is a release confirmation switch, 15 is a center detection switch, 16 is a rear wheel steering switch, 17 is a power source, 18a to 18e are relays, and 21 and 22 are indicators.

Claims (1)

[Scope of utility model registration request] It has hydraulic cylinders 5, 5 for front wheel steering and hydraulic cylinders 6, 6 for rear wheel steering, and between these hydraulic cylinders 5, 5, 6, 6 and the steering valve 3, Neutral position a where pressure oil is sent only to the hydraulic cylinders 5, 5, and Four-wheel steering operation front and rear wheel reverse phase steering position b where pressure oil is sent to each of the above hydraulic cylinders 5, 5, 6, 6.
and an electromagnetic steering switching valve 1 having crab steering operation front and rear wheels same phase steering position c, and a steering mode switch 7 is connected to the electromagnetic solenoid for switching of this steering switching valve 1. The rear wheel steering lock device also has a lock pin 10 for locking rear wheel steering operation, and an electromagnetic lock operation valve 12 is interposed between a hydraulic cylinder 11 that operates the lock pin 10 and a hydraulic power source. A rear wheel steering switch 16 is provided which has a lock position for locking the rear wheel steering and a release position for locking the rear wheel steering.
2 locking solenoid 12a and power supply 17,
One terminal of the first relay 18a is connected to the power supply when the rear wheel steering switch 16 is in the lock position, and it is turned on when the rear wheels are in a straight-ahead state.
The third relay 18c is connected via the fourth relay 18d, which is turned on when the lock is released, and the release solenoid 12b of the lock operation valve 12 and the power supply 17 are connected to the rear wheel steering. switch 1
6 is in the release position, the first
The other terminal of the relay 18a is connected via the second relay 18b, which is turned on when the lock is released, and the steering mode switch 7 is turned on only when the lock is released. A rear wheel steering lock device characterized in that it is connected to a power source via a switch 14.