JPS5823734Y2 - anti-stress - Google Patents

Description

[Detailed description of the invention] This invention is an anti-skid pressure regulating device that is pressed during braking and operates to lower the brake pressure and maintain a suitable slip ratio between the wheels and the road surface when the skidding state of the wheels is detected. It is related to.

Conventionally, this type of device is known to include a pressure reducing device that operates a hydraulic pressure control plunger using a power piston that moves based on the pressure difference between two air chambers.

However, this configuration has the disadvantage that the device is large, complicated, and expensive, and that the recovery rate of brake pressure can only be controlled at a constant rate or in stages.

The present invention eliminates these drawbacks and has developed an anti-skid pressure regulating device that can change the recovery of brake pressure steplessly while maintaining a suitable slip ratio for the road surface and wheels.

The present invention will be explained based on the embodiment shown in the drawings.
In the figure, 1 is a brake pedal, 2 is a master cylinder, 3 is a control valve, and 4 is a first hydraulic pressure transmission path, which connects the master cylinder 2 to the brake device (not shown) via the control valve 3. and are connected.

A reservoir 5 is connected to the control valve 3 through a third hydraulic pressure transmission path 6, and is also connected to the master cylinder through a reflux pump 7.

Reference numeral 8 denotes a pressure regulating valve for restoring brake pressure, which is connected between the master cylinder 2 and the brake device through a second hydraulic pressure transmission path 9 so as to be parallel to the control valve 3 .

The preferred brake pressure recovery according to the present invention is due to the operating characteristics of the pressure regulating valve 8, whose structure and operation will be explained in detail with reference to the enlarged view of FIG. 2.

10 is a solenoid, and 11 is an anti-skid control circuit, which outputs a brake pressure drop signal when a wheel slippage is detected during braking to change the control valve 3 from the normal communication state shown in FIG. 1a. 1C to the communication state (that is, the first path 4 is shut off and the third path 6 is connected), and when the wheel skidding state is no longer detected, a brake pressure recovery signal is output and the control valve 3 is activated. This transitions to the communication state shown in FIG. 1 (that is, both the first and third paths 4 and 6 are blocked).

In FIG. 2, a conical plunger 13 is housed in the pulp body 12 so as to be movable in the axial direction passing through the pulp body cylindrical portion 12'. ) is the first
It is located in the hydraulic pressure chamber 14, and its axially central portion is located in a second hydraulic pressure chamber 15 communicating with the master cylinder 2, and the other end is hydraulically sealed from the second hydraulic pressure chamber 15. It protrudes into the spring chamber.

16 is a spring that presses the plunger 13 toward the conical tip side, 17 is a spring support, and 18 is a hydraulic seal.

Further, when the plunger 13 is stationary at the rightmost end as shown in FIG.
3 has a minute gap, and the first hydraulic pressure chamber 14 and the second hydraulic pressure chamber 15 are communicated with each other through this gap.

Next, the operation of the anti-skid pressure regulating device constructed as described above will be described.

(g) During normal braking, the control valve 3 is in the communication state shown in FIG. 1a, and hydraulic pressure is directly transmitted from the master cylinder 2 to the brake device.

(Extension) When the skid state of the wheels is detected during braking, the anti-skid control circuit 11 outputs a brake pressure drop signal and the control valve 3 shifts to the state shown in FIG. 1C.

Therefore, the brake pressure escapes to the reservoir 5 and rapidly drops.

(c) When the skid state of the wheels is no longer detected due to a drop in brake pressure, the anti-skid control circuit 11 outputs a brake pressure recovery signal and the control valve shifts to the state shown in FIG. 1.

Therefore, as shown in the figure, communication between the master cylinder 2 and the brake device is only through the 20th hydraulic pressure transmission path 9 via the pressure regulating valve 8, and the above-mentioned conical plunger 13
The brake pressure is gradually restored through the gap between the pulp body cylindrical portion 12' and the pulp body cylindrical portion 12'.

FIG. 3 shows a basic diagram of this brake pressure P recovery.

That is, the plunger 13 resists the pressing force of the spring 16 due to the increase in brake pressure acting on the conical tip surface, and moves to the second position.
The brake pressure recovery rate gradually increases because the above-mentioned gap increases with this movement.
This results in a downwardly convex characteristic curve as shown in the figure.

In addition, in the process (a) described above, the plunger 13 moves to the left in FIG. ), the duration ja, tb, tc of the state α0 is the starting point of brake pressure recovery shown in Figure 3 a, b, c (in other words, the gap at the start of brake pressure recovery). amount).

In other words, since the coefficient of friction of the road surface is low, recovery of the wheel speed is slow, and when the brake pressure of the brake device drops to a low point a, the amount of leftward movement of the plunger 13 due to the brake pressure is small.

Therefore, the gap between the cylindrical portion 12' and the plunger 13 is small, and the brake pressure increases slowly through that gap.
Re-skidding of the wheels is reliably prevented.

Since the friction coefficient of the road surface is high, when the wheel speed recovers quickly and the brake pressure drops only to point C, the plunger 13 has moved largely to the left due to the high brake pressure at point C.

Therefore, the brake pressure increases quickly through the large gap between the cylindrical portion 12' and the plunger 13, thereby preventing the brake pressure from becoming too loose.

These relationships are shown in Figures 4, 5, and 6. When the road surface friction coefficient μ is low (Figure 4), the above condition ←) remains for a long time, and the brake pressure Pa drops significantly. Afterwards, it begins to recover slowly.

When the coefficient μ is high (FIG. 6), on the other hand, the drop in brake pressure Pc is relatively small and therefore shows a rapid recovery.

FIG. 5 shows these intermediate states.

As described above, the anti-skid pressure regulating device according to the present invention is capable of performing stepless brake pressure recovery control while maintaining a suitable slip ratio between the wheels and the road surface, and has a simple and inexpensive structure. Furthermore, by changing the shape of the conical plunger in the pressure regulating valve mentioned above, various brake pressure recovery characteristics can be selected, and the function of this pressure regulating valve is used in the brake pressure decreasing process to gradually increase the rate of increase in brake pressure. It is also possible to construct such an anti-skid pressure regulating device, and the anti-skid control provides even better safety during braking, and its practical effects are extremely significant.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is a block diagram of the anti-skid pressure regulating device, Fig. 2 is a sectional view of the pressure regulating valve, Fig. 3 is a diagram of the basic characteristic curve of brake pressure, and Fig. 4 is a diagram of the basic characteristic curve of brake pressure. 5 and 6 are brake pressure recovery characteristic curve diagrams when divided by the value of the road surface coefficient μ, respectively. 1... Brake pedal, 2... Master cylinder 3
... Control valve, 4... First hydraulic pressure transmission path, 5... Reservoir, 6... Second hydraulic pressure transmission path, 7... Pump, 8... Pressure regulating valve, 9...・Third hydraulic pressure transmission path, 10・
...Solenoid, 11...Anti-skid control circuit,
DESCRIPTION OF SYMBOLS 12... Valve body, 1z... Valve body cylindrical part, 13... Conical plunger, 14... First hydraulic pressure chamber, 15... Second hydraulic pressure chamber, 16... spring,
17... Spring support, 18... Hydraulic seal.

Claims (1)

[Scope of utility model registration request] When a first hydraulic pressure transmission path having a control valve interposed therebetween and a second hydraulic pressure transmission path having a pressure regulating valve interposed therebetween are connected in parallel between the hydraulic pressure source and the brake device, the above-mentioned control valve normally communicates the hydraulic pressure source with the brake device, communicates the brake device with the reservoir via the third hydraulic pressure transmission path when a brake pressure drop signal is input, and communicates the brake device with the reservoir via the third hydraulic pressure transmission path when a brake pressure recovery signal is input. and a 30th hydraulic pressure transmission path, and the pressure regulating valve includes a plunger that can be moved in the axial direction against a spring force by the action of brake pressure, and the plunger is arranged in the cylindrical part. The hydraulic pressure source and the brake device are communicated with each other through a minute gap formed between the conical portion and the inner periphery of the cylindrical portion, and the brake pressure is changed from the minimum gap state when the plunger is at rest. An anti-skid pressure regulating device characterized in that the gap is configured to gradually increase as the plunger moves against the spring force as the gap increases.