JPH0319508Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an emergency steering system for a vehicle such as a dump truck equipped with a hydroneumatic suspension.

Conventional Technology Conventionally, power steering has been adopted in large vehicles such as dump trucks. Therefore, if the power source that supplies hydraulic pressure to the power steering circuit breaks down while the vehicle is running, there is a risk that the vehicle will be unable to steer the vehicle.

Problems that the invention aims to solve Conventionally, it was stipulated that an emergency power source be installed in the vehicle in preparation for the above situations.
When trying to obtain a power source that satisfies the regulations from an accumulator, there were problems such as the capacity of the accumulator becoming large, requiring a large space to be mounted on a vehicle, and the accumulator itself becoming expensive.

This invention was made for the purpose of improving the above-mentioned problems.

Means and Effects for Solving the Problems In an apparatus in which hydraulic pressure discharged from a variable pump is supplied to a steering cylinder via a steering valve, and a portion is supplied to a suspension cylinder via a leveling valve, The above-mentioned leveling valve is provided with an emergency position that can be switched by an emergency steering switch, and the accumulator connected to the suspension cylinder side can be connected to the steering side pipe through this emergency position. An emergency steering system for a vehicle that allows hydraulic pressure from the suspension side accumulator to be used for steering even if the power source fails by simply turning on the emergency steering switch.

Embodiment This invention will be described in detail with reference to an illustrated embodiment. In the figure, 1 is a variable pump, and oil discharged from the variable pump 1 is sent to a steering cylinder 3 via a steering valve 2 through a pipe 4. The steering wheel (not shown) is steered by the steering cylinder 3, and the variable pump 1
A part of the discharge pressure reaches the accumulator 6 and the leveling valve 7 through a conduit 5 branched from the conduit 4, and a part of the discharge pressure is accumulated in the accumulator 6.

Leveling valve 7 is at leveling position 7
a and an emergency position 7b, and is normally held in one of the leveling positions 7a by a signal sent from the leveling controller 8. The leveling position 7a is composed of a neutral position ₇₂ , a raised position ₇₁ , and a lowered position ₇₃ , and leveling is performed as follows. That is, the leveling valve 7 has a suspension cylinder 1 provided with an accumulator 9 on the bottom side.
0 is connected, and a pair of position detectors 11 are installed in the vicinity of the piston rod 10a of the suspension cylinder 10, vertically spaced apart from each other.
When the vehicle height lowers due to the load, etc., the position detector 11 detects this and sends a signal to the level controller 8, so the level controller 8 outputs a control signal to the leveling valve 7, and the leveling valve 7 raises. The position is switched to position 7 ₁ , and the discharge pressure of variable pump 1 is changed to suspension cylinder 1.
The vehicle is supplied to the bottom side of the vehicle and raised until the vehicle height reaches a certain level.

Also, if the vehicle height is too high, the position detector 11 detects this.
is detected and sends a signal to the level controller 8, so the leveling valve 7 is lowered to the lower position ₇₃ by the signal from the level controller 8.
Since the discharge pressure of the variable pump 1 is supplied to the rod side of the suspension cylinder 10, the vehicle height is always maintained constant.

On the other hand, the leveling valve 7 is also electrically connected to an emergency steering switch 12, and when the emergency steering switch 12 is turned on, it is switched to the emergency position 7b. As a result, the accumulator 9 provided for each wheel is connected to the conduit 4 on the steering side via the emergency position 7b, so that the hydraulic pressure accumulated in the accumulator 9 can be supplied to the steering cylinder 3 side. Even if the power source fails while driving and steering becomes impossible, by turning on the emergency steering switch 12,
It becomes possible to stop the vehicle in a safe place while performing steering operations.

Effects of the invention As detailed above, with this invention, even if the power source fails while the vehicle is running and steering becomes impossible, simply turning on the emergency steering switch will automatically turn the accumulator installed in the suspension on. Since hydraulic pressure can be used for steering, there is no need to mount a large accumulator on the vehicle in advance for emergency use. This eliminates the need for extra space for mounting a large accumulator on the vehicle, and also reduces costs.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of this invention. 1 is variable pump, 2 is steering valve, 3
is a steering cylinder, 4 is a conduit, 7 is a leveling valve, 7b is an emergency position, 9 is an accumulator, 10 is a suspension cylinder, 1
2 is an emergency steering switch.

Claims (1)

[Scope of utility model registration request] The hydraulic pressure discharged from the variable pump 1 is supplied to the steering cylinder 3 via the steering valve 2, and a portion is supplied to the suspension cylinder 10 via the leveling valve 7. A vehicle is provided with an emergency position 7b that can be switched by an emergency steering switch 12, and an accumulator 9 connected to a suspension cylinder 10 side can be connected to a steering side conduit 4 via this emergency position 7b. emergency steering system.