JPS5951468B2 - Anti-skid control device with load response mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an anti-skid control device for eliminating a wheel lock condition that may occur when braking a vehicle.

The anti-skid control device includes an anti-skid circuit that detects a locked state of wheels during braking and outputs a brake pressure drop signal, and a pressure reducing device that lowers the brake pressure in response to input of this signal.

Since the wheel braking force is controlled by controlling the operation of the pressure reducing device, detailed operation control is required to maintain a suitable slip ratio between the road surface and the wheels.

Generally, a pressure reducing device is a system that determines the positive brake value by sliding a power piston that divides the inside of the case into two high and low air chambers based on the pressure difference between these two air chambers, so the brake pressure will eventually drop. It can be said that fine control of the rise can be achieved by finely controlling the pressure difference between the two air chambers that cause the sliding movement of the power screw.

The present invention focuses on this point, and detects the load capacity of the vehicle, which has a large influence on the fluctuation of the slip ratio between the wheels and the road surface.
The rate of change in the pressure difference between the two chambers of the decompression device is made variable.

In other words, when the friction coefficient of the road surface is constant, the smaller the load carrying capacity, the more likely the wheels will lock.Therefore, in anti-skid control, it is necessary to reduce the brake pressure quickly, but on the other hand, when the load is This is because if the amount increases, if the brake pressure is lowered too much, the braking distance will increase.

The present invention will be explained below with reference to embodiments shown in the drawings.

In FIG. 1, 1 is a pressure reducing device, and a power piston 5 that divides the inside of the case 2 into two high and low air chambers 3 and 4 is normally moved into a high pressure chamber by the pressing force of a return spring 6 in the low pressure chamber 4.
biased into position on the side.

Reference numeral 7 denotes a plunger that can slide within the cylinder 8 and follow the sliding movement of the power piston 5, and one end faces a decompression chamber 9 communicating with the foil cylinder.

A valve chamber 10 communicates with the mask cylinder, and is provided so that when the plunger slides, the ball valve abuts against the valve seat and communication with the decompression chamber 9 is cut off.

The above configuration is similar to a known pressure reducing device, and when the plunger 7 or power piston 5 moves to the left in the figure (toward the low pressure chamber 4 side), communication between the pressure reducing chamber 9 and the valve chamber 10 is cut off, and The brake pressure is lowered by increasing the volume of the decompression chamber 9.

Furthermore, the low pressure chamber 4 is connected to a negative pressure source such as the engine intake manifold! An orifice 11 is provided in the power screw 5 to communicate the high pressure chamber 3 and the low pressure chamber 4.

Reference numeral 12 denotes a solenoid valve for opening/closing a flow path interposed in a flow path connecting the high pressure chamber 3 and the atmosphere, and is provided to open in response to input of a brake pressure drop signal from the anti-skid control circuit.

Reference numeral 13 denotes a throttle valve, which, like the electromagnetic valve 12, is interposed in a flow path that connects the high pressure chamber 3 to the atmosphere.

This throttle valve 13 is interlocked with a load response mechanism 16 that collects the amount of relative movement between the vehicle body 14 and the axle 15, and the displacement x = It is provided so that the drawing ratio increases in proportion to l -1'(1' is the interval during load loading).

The configuration of this interlocking connection is easily achieved by known technical means such as a link mechanism.

Next, talking about its operation, when it is stationary, the height
Since the air chambers 3 and 4 are in communication with each other through the orifice 11, they are at the same pressure, and are biased to a predetermined position by being pressed by the return spring 6.

When a brake pressure drop signal is input to the electromagnetic valve 12 from the anti-skid control circuit, the valve 12 opens and the atmosphere flows into the high pressure chamber 3 via the throttle valve 13.
A differential pressure is generated between the power pistons 4 and 4, and the power piston 5 begins to slide toward the low pressure chamber 4.

Since the plunger slides following the sliding of the power piston 5, the brake is lowered as described above, but the sliding speed of the power piston 5 determines the brake lowering rate, and the sliding Since the speed is determined by the differential pressure state between the two high and low air chambers 3 and 4, that is, the rate of inflow of the atmosphere into the high pressure chamber 3, the throttle ratio of the throttle valve 13 is increased as the vehicle load capacity increases, and as a result, the brake The rate of descent increases the longer the vehicle is empty.

FIG. 2 shows a second embodiment in which a three-way solenoid valve 17 is provided in the path connecting the atmosphere and the high pressure chamber 3 via the throttle valve 13. communicate,
It is provided so that communication between the high pressure chamber 3 and the negative pressure source is cut off by electromagnetic switching, and at the same time, the high pressure chamber 3 is communicated with the atmosphere via the throttle valve 13.

Its action and effect are substantially the same as in the first embodiment. In FIG. 3, contrary to Embodiment 1.2, the oil pressure increase rate is varied by the control valve 13, and the effect of maintaining a suitable slip ratio when the oil pressure that has dropped is increased again can be expected.

As described above, the anti-skid control device having a load response mechanism according to the present invention is capable of controlling the brake pressure to drop and rise again in a suitable manner according to changes in the load capacity of the vehicle. The profits are extremely large.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1 shows embodiment 1.
FIG. 2 is a partial schematic diagram showing the second embodiment, and FIG. 3 is a partial schematic diagram showing the third embodiment. 1... pressure reducing device, 2... case, 3.
...High pressure chamber, 4...Low pressure chamber, 5...
... Power screws 1 to 6, Return spring, 7... Plunger, 8... Cylinder, 9... Decompression chamber, 10... ... Valve chamber, 11 ... Orifice, 12 ... Solenoid valve, 13 ... 1 valve, 14 ... Car body, 15 ... ...Axle, 16...Load response mechanism, 17...3-way solenoid valve.

Claims (1)

[Claims] 1 In an anti-skid control system for a vehicle equipped with a pressure reducing device in which a power piston that divides the inside of the case into two high and low air chambers slides to lower and increase brake pressure due to changes in pressure between these two air chambers, wheel locking is performed. A crest valve is interposed in the gas flow path that communicates the high pressure chamber and the high pressure source in response to input of a state detection signal, and the crest valve is installed in a gas flow path that communicates the high pressure chamber with the high pressure source, and the crest valve is arranged approximately in proportion to the amount of relative movement between the vehicle body and the axle that approaches asymptotically as the load carrying capacity increases. An anti-skid control device having a load response mechanism characterized by increasing the throttling rate of a throttle valve.