JPH0127902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid device that eliminates a wheel lock condition that may occur when braking a vehicle by lowering brake fluid pressure by operating a fluid pressure control valve.

In general, anti-skid devices electrically detect when a wheel slipping condition (locked condition) occurs and activate a brake fluid pressure reducer, and then extend the braking distance when the wheel skidding condition is resolved. As one of this type of device, the applicant has proposed
A control valve type anti-skid device is provided in which a flow path opening/closing valve, a liquid return pump, a throttle valve, etc. are interposed between a master cylinder and a brake device.

Its basic structure is that three liquid chambers, first, second, and third, are formed in the valve body.The first liquid chamber is connected to the master cylinder, and the second liquid chamber is connected to the master cylinder through a brake device and a throttle valve. The third liquid chamber is connected to the master cylinder via a liquid reflux pump, and opens and closes the communication path between the first and second liquid chambers and the communication between the second and third liquid chambers. First thing to do
and a second valve part, and when it is stationary, the first valve part is opened and the second valve part is opened to adjust the hydraulic pressure of the master cylinder to the first valve part.
The signal is transmitted to the brake device via the fluid chamber and the second fluid chamber, and when an anti-skid signal (brake fluid pressure drop signal) is input, the opening and closing of the first and second valve portions are reversed, and the signal is transmitted from the master cylinder to the brake device. At the same time, the pressure fluid in the brake device is returned to the master cylinder via the third fluid chamber and the fluid return path pump to lower the brake fluid pressure, and when the input of the anti-skid signal is stopped, Pressure fluid is gradually transmitted from the master cylinder to the brake device, which is connected to the brake device by closing both the first and second valve portions, and the fluid in the second fluid chamber is gradually transmitted through the throttle valve. The pressure increase is the first
When the liquid pressure in the liquid chamber reaches a predetermined ratio, the first valve portion is opened based on the liquid pressure balance between the two liquid chambers to return to the stationary state (initial state).

By the way, considering the drop/rise characteristics of the brake fluid pressure in such a configuration, the re-rise characteristics of the brake fluid pressure, which is particularly important for preventing wheels from relocking during anti-skid control, depend on the flow path diameter of the throttle valve. If this diameter is constant, it will be affected by the differential pressure relationship between the master cylinder and the brake device, and the larger the differential pressure, the faster the fluid pressure in the second fluid chamber (brake device) will increase. It will be raised to In other words, the characteristic line when the brake fluid pressure rises again after it drops shows a tendency for the rate of rise in fluid pressure to gradually decrease as shown in line A in Figure 1. This is due to the rapid rise in the initial stage, which is caused by the prevention of wheel relock. It was not desirable from that point of view.

The present invention aims to make the brake fluid pressure re-rise characteristic during anti-skid control more desirable by improving the above-mentioned throttle valve, and to increase the degree of freedom in selecting the characteristic according to the vehicle type. Specifically, a first fluid chamber connected to a fluid pressure source, a second fluid chamber connected to a brake device and connected to the fluid pressure source via a throttle valve, and a fluid chamber connected to a fluid pressure source. three liquid chambers, a third liquid chamber connected to the liquid pressure source via a reflux pump; a first valve portion that opens and closes a first flow path between the first and second liquid chambers; and a second and third liquid chamber.
a second valve portion that opens and closes a second flow path between the liquid chambers;
When stationary, the first valve part is opened and the second valve part is closed to transmit the hydraulic pressure from the hydraulic pressure source to the brake device, and when the anti-skid signal is input, the opening and closing of the first and second valve parts are reversed to control the hydraulic pressure of the brake device. is refluxed to the hydraulic pressure source,
When the input of the anti-skid signal is stopped, the first and second
While closing the valve part, when the liquid pressure in the second liquid chamber, which is gradually increased through the throttle valve, rises again to a predetermined proportion of the liquid pressure value in the first liquid chamber, the first valve part is opened and brought to a stationary state. In the anti-skid device configured to return, the throttle valve includes a valve seat that divides the valve chamber into an input liquid chamber on the side of the liquid pressure source and an output liquid chamber on the side of the second liquid chamber, and a flow path in the valve seat. A valve shaft is provided so as to be movable in the axial direction by passing through the valve shaft, and has a tapered part that gradually reduces the liquid flow gap between the inner diameter of the valve seat and the inner diameter of the valve seat by moving toward the output liquid chamber side. and a spring mechanism that biases a spring force to the valve shaft, and is configured such that a liquid flow thrust from the input liquid chamber to the output liquid chamber acts on the valve shaft as a moving force against the biasing spring force. This is an anti-skid device.

The present invention will be described below based on embodiments shown in the drawings.

FIG. 2 shows an anti-skid device including a hydraulic piping system, in which 1 is a brake pedal, 2 is a master cylinder, 3 is a hydraulic pressure transmission path, and 4 is an anti-skid control valve. 2 and third liquid chambers 6, 7, and 8 are formed. This first liquid chamber 6 is connected to the master cylinder 2 via the hydraulic pressure transmission path 3, and the second liquid chamber 7 is connected to a brake device (wheel cylinder) and a throttle valve 9.
The third liquid chamber 8 is connected to the hydraulic pressure transmission path 3, that is, the master cylinder 2, via a liquid reflux pump 10. 11 is a hydraulic pressure transmission path from the throttle valve 9 to the second liquid chamber 7; 12 is a passage from the third liquid chamber 8 to the pump 1;
This is the liquid reflux path to 0. Reference numeral 13 designates a solenoid built into the third liquid chamber 8 side in the body 5 of the anti-skid control valve 4, and reference numeral 14 designates the solenoid 13.
The armature is moved by the excitation of the armature, and is normally biased toward the third liquid chamber 8 (to the left in the figure) by the spring force of the return spring 15. The solenoid 13 is energized by receiving an anti-skid signal _S1 generated by an anti-skid control circuit (not shown) upon detecting a locked state of the wheels during braking of the vehicle.

A valve shaft 16 extends from the armature 14, passes through the third liquid chamber 8 and the second liquid chamber 7, and is formed to protrude into the first liquid chamber 6. The valve seat 18 is provided so that a ball 19 pushed against the valve seat 18 by a spring 17 can be moved away from the valve seat 18. In the illustrated state, the armature 14 is biased to the leftward limit position by the spring force of the return spring 15, causing the ball 19 to move away from the valve seat 18. The communication path 20 between the liquid chambers 7 is open. When the valve stem 16 moves to the right, the ball 19 comes into contact with the valve seat 18 and the communication passage 20 is closed, and the movement of the valve stem 16 causes the gap between the first and second liquid chambers 6 and 7 to be closed. It constitutes a first valve part that opens and closes the communication passage 20 of.

Reference numeral 21 denotes a communication path of a vertical hole formed in the shaft portion of the valve stem 16. When the opening at the tip of the valve stem 16 is in contact with the ball 19, the communication path is closed and the ball 1
It is provided so that it opens when the contact with 9 is released. Therefore, the communication passage 21 closes the communication passage 20 between the first and second liquid chambers 6 and 7 when the first valve part closes the communication passage 20 between the first and second liquid chambers 6 and 7, and further closes the second liquid chamber 7 only when the tip of the valve shaft 16 is separated from the ball 19. and the third liquid chamber 8, and when the armature 14 is moved to the left in the figure by the excitation of the solenoid 13, the second and third liquid chambers are connected to each other. 7 and 8 are connected to each other. 22 and 23 are piston cups that seal the sliding portion of the valve shaft 16, respectively.

To explain the operation of the anti-skid control valve with the above configuration, in the stationary state shown in the figure, the first
Since the valve part is open and the second valve part is closed, the hydraulic pressure generated in the master cylinder 2 is transmitted to the brake device via the first liquid chamber 6 and the second liquid chamber 7 (line C in FIG. 1).

When the solenoid 13 is energized by the input of the anti-skid signal _S1 , the armature 14 and the valve shaft 16 are activated.
is moved to the right in the figure, the ball 19 comes into contact with the valve seat 18 to close the first valve part, and the valve shaft 16
The tip of the valve is separated from the ball 19 and the second valve part opens.
Therefore, the hydraulic pressure in the second hydraulic chamber 7, that is, the brake hydraulic pressure P in the brake device, is returned to the master cylinder 2 side via the third hydraulic chamber 8 and the pump 10 and is lowered (line D in FIG. 1).

After that, when the input of the anti-skid signal _S1 is stopped, the armature 14 and the valve stem 16 are returned to the left in the figure by the return spring 15.
Since the ball 19 is strongly pressed against the valve seat 18 by the differential pressure between the first and second liquid chambers 6 and 7, the valve shaft 16 abuts against the ball 19 and further return movement is stopped. Ru. Therefore, both the first and second valve portions are closed, and hydraulic pressure is gradually transmitted to the second hydraulic pressure 7 from the master cylinder 2 side via the throttle valve 9. and the second
The liquid pressure _P2 in _the liquid chamber 7 is relative to the liquid pressure _P1 in the first liquid chamber ₆ . When the spring force of the return spring 15 is reached, the valve stem 16 pushes the ball 19 to open the first valve portion, and the device returns to its resting state (initial state).

At this time, when the hydraulic pressure in the second liquid chamber 7, that is, the brake hydraulic pressure P in the brake device, rises again, if the throttle valve is an orifice with a constant diameter, it will become convex upward as shown in line A in Figure 1. As already mentioned, the characteristics are shown.

On the other hand, when the throttle valve 9 of this example is used, the liquid pressure re-rise characteristic of the second liquid chamber 7 can be made substantially linear as shown in line B in FIG. , there is an advantage that various characteristics can be selected depending on the design.

The configuration and operation of the throttle valve 9 of this example will be explained below. 24 is the body of the throttle valve 9, 25 and 26 are input and output liquid chambers formed in the body 24,
The input liquid chamber 25 is connected to the master cylinder 2 via the hydraulic pressure transmission path 3, and the output liquid chamber 26 is connected to the second liquid chamber 7 via the hydraulic pressure transmission path 11. 2
7 is a valve seat that divides these input and output liquid chambers 25 and 26, and 28 and 29 are these input and output liquid chambers 25 and 26.
The cylinders 30 have the same diameter and are formed to face the left and right outer walls of the cylinders 28 and 30, respectively.
29, and a tapered part 31 whose diameter gradually increases toward the input liquid chamber 8 is formed on the shaft part that passes through the inner diameter part of the valve seat 27. It is slightly pressed and biased towards the 25 side.

According to such a configuration, when pressure liquid flows from the input liquid chamber 25 in a high pressure state to the output liquid chamber 26 in a low pressure state, this flowing liquid causes the valve shaft 30 to flow in the direction of the output liquid chamber 26. A thrust force acts on the valve shaft 3 due to the relationship with the spring force set in the spring 32.
0 is moved slightly by the thrust, and as a result, the tapered portion 31 advances into the valve seat 27 and the valve shaft 30
The amount of gap between the tapered portion 31 and the valve seat 27 is reduced.

This gap reduction is large because when the differential pressure between the input and output liquid chambers 25 and 26 is large, a thrust force due to a large liquid flow acts on the valve shaft 30, and it gradually decreases as the differential pressure decreases. The gap amount shows an inversely proportional relationship to the differential pressure between the input and output liquid chambers 25 and 26. Figure 3 A shows that when this differential pressure is small,
FIG. 3B shows the positional relationship of the valve shaft 30 when the differential pressure is large.

As is clear from the above relationship, the re-rise characteristic of the brake fluid pressure P in the throttle valve 9 of this example is such that when a rapid rise occurs due to a large differential pressure, the throttle ratio is increased, and other If the differential pressure decreases and the rise of the brake fluid pressure P becomes gradual, reduce the throttling ratio to allow the brake fluid pressure P to rise again approximately linearly as shown in line B in Figure 1. It was decided that it would be done.

FIG. 4 shows another embodiment of the throttle valve 9', in which a piston 33' for adjusting the spring force of a spring 32' is arranged in the large diameter part of the cylinder 28, which receives the liquid pressure of the second liquid chamber 7 as back pressure. The spring force of the adjustment spring 34' is biased against the back pressure of the adjustment piston 33'.
The degree of adjustment of the spring force of 2' can be selected.

In the case of this example, in addition to varying the throttling rate by the thrust of the liquid flow acting on the valve shaft 30',
Furthermore, the spring force applied to the valve stem, which resists this thrust and determines the throttling rate, can be varied based on the state of the brake fluid pressure P rising again. It is also possible to make the pressure re-rise characteristic downward convex.

As described above, the anti-skid device according to the present invention has a wide range of options for re-rising the brake fluid pressure during anti-skid control, such as making it gentle when the pressure is low and steeply as the pressure increases, thereby preventing wheels from relocking. The practical benefits are extremely large, such as being able to effectively achieve the following.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the brake fluid pressure control characteristics of the anti-skid device of the present invention in comparison with a conventional example.
The figure is a partial sectional view including the brake hydraulic piping of the anti-skid device of the present invention, Figures 3A and 3B are diagrams showing the operating states of the throttle valve, respectively, and Figure 4 is a diagram showing another embodiment of the throttle valve. It is. DESCRIPTION OF SYMBOLS 1... Brake pedal, 2... Master cylinder, 3, 11... Hydraulic pressure transmission path, 4... Anti skid control valve, 5... Body, 6... First liquid chamber,
7...Second liquid chamber, 8...Third liquid chamber, 9,9'...
Throttle valve, 10...pump, 12...liquid return path,
13...Solenoid, 14...Amateur, 15
...Return spring, 16...Valve stem, 17...
... Spring, 18 ... Valve seat, 19 ... Ball,
20... Communication path, 21... Communication path, 22, 23...
...Piston cup, 24, 24'...Body, 2
5, 25'... Input liquid chamber, 26, 26'... Output liquid chamber, 27, 27'... Valve seat, 28, 28'... Cylinder, 29, 29'... Cylinder, 30, 30'...
... Valve stem, 31, 31'... Taper part, 32, 3
2'...Spring, 33'...Adjustment piston,
34'...adjustment spring.

Claims (1)

[Scope of Claims] 1. A first fluid chamber connected to a fluid pressure source, a second fluid chamber connected to a brake device and to the fluid pressure source via a throttle valve, and a fluid reflux pump. and a first fluid chamber that opens and closes a first flow path between the first and second fluid chambers.
It is equipped with a valve part and a second valve part that opens and closes a second flow path between the second and third liquid chambers, and when it is stationary, the first valve part is opened and the second valve part is closed, and the liquid pressure from the liquid pressure source is removed. is transmitted to the brake device, and when the anti-skid signal is input, the opening and closing of the first and second valve portions are reversed to return the hydraulic pressure of the brake device to the hydraulic pressure source, and when the anti-skid signal input is stopped, the first and second valve portions are reversed. When the fluid pressure in the second fluid chamber is closed and the fluid pressure in the second fluid chamber is gradually increased through the throttle valve and rises again to a predetermined percentage of the fluid pressure value in the first fluid chamber, the first valve portion is opened to return to a stationary state. In the anti-skid device configured, the throttle valve has a valve seat that divides the valve chamber into an input liquid chamber on the side of the liquid pressure source and an output liquid chamber on the side of the second liquid chamber, and a flow path in the valve seat that is inserted through the valve seat. a valve stem that is movable in the axial direction and has a tapered part that gradually reduces the liquid flow gap between the inner diameter of the valve seat and the inner diameter of the valve seat as it moves toward the output liquid chamber; An anti-skid device comprising a spring mechanism for biasing force, and configured such that liquid flow thrust from the input flow chamber to the output liquid chamber acts on the valve shaft as a moving force against the biasing spring force. . 2. The anti-skid device according to claim 1, wherein the spring mechanism of the throttle valve is a spring. 3. The anti-skid device according to claim 2, wherein the spring of the spring mechanism of the throttle valve is engaged with a spring force amplifying piston that receives output hydraulic pressure as back pressure.