JPS637985B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control device for double piping in a vehicle brake system.

It has long been known that when braking a vehicle, the braking force on the front and rear wheels needs to be reduced by a predetermined percentage compared to the front wheel due to the difference in the pressing force of the wheels against the road surface. .

For this purpose, a proportioning type or a limiting type hydraulic pressure control device that distributes and controls front and rear wheel brake fluid pressure is provided, and in order to further improve vehicle safety, a double piping type brake fluid system is used. In this case, an active proportioning actuated (or limiting actuated) valve mechanism is installed in one system, and the hydraulic pressure of the other system is controlled in conjunction with the operation of this valve mechanism. A dual piping hydraulic control device with a driven valve mechanism is also provided.

The present invention relates to an improvement of this type of hydraulic pressure control device for double piping. In other words, a brake fluid system with double piping has the effect of improving safety because when one system fails, the braking force is secured by the fluid pressure of the other system, but if one system fails, Sometimes, the entire vehicle's brake system tends to be insufficient. Therefore, in this case, it is desirable to cancel the reduction control of the rear wheel brake fluid pressure under normal conditions and transmit the same hydraulic pressure to the front wheels to the rear wheels to compensate for the lack of braking force in the entire vehicle. The present invention provides a configuration suitable for this purpose, and specifically, a cylindrical fail-safe piston that is slidably fitted to a valve cylinder,
A balance piston is slidably fitted to the middle cylinder inside the fail-safe piston and divides the valve chamber into left and right A and B system liquid chambers, and a balance piston is disposed inside the A system liquid chamber and is biased by a hydraulic action. A pressure reduction control type valve mechanism that controls the opening and closing of the input and output liquid chambers a ₁ and a ₂ by the operation of a control piston that moves backward from the balance piston against force, and・By moving in the direction of the control piston that balances the fluid pressure in the B system output fluid chamber, the input and output fluid chambers b ₁ , b ₂
In a hydraulic pressure control device for double piping equipped with a driven type valve mechanism for controlling opening and closing, a fail is fitted and fixed to the former and loosely fitted to the latter between opposing parts of the control piston and the balance piston. A safety clip is installed to regulate the left and right separation limits of both to a constant value, and the failsafe clip abuts against the failsafe piston to stop movement of the control piston due to the biasing spring force. This is a hydraulic pressure control device for double piping characterized by having the following configuration.

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

In the figure, 1 is a valve body, 2 and 2' are valve cylinders formed at one end of the valve chamber,
A blind hole cylinder 3 is formed at the other end of the valve chamber so as to face the valve cylinders 2 and 2', and is open at the inner end of the plug 4 that closes the valve chamber. 5, 5' are valve cylinders 2,
a cylindrical fail-safe piston slidingly fitted to the first portion 5 of the fail-safe piston;
A middle cylinder 6 is formed in the valve chamber 6, and a balance piston 7 is slidably fitted to the valve chamber A/B2.
The fail-safe pistons 5, 5' are biased by a small spring force of a hold spring 14 through the valve seats 11, and the valve cylinders 2, 2' are It is pressed into engagement with the body wall of the B system side liquid chamber.

Further, the balance piston 7 is formed with extending portions on both left and right sides, and the extending portion into the B system chamber is a valve body portion 8 that cooperates with the valve seat 24 described below to form a driven valve mechanism. and the other A
The extending portion into the system chamber is provided with a circumferential groove 9 into which a fail-safe clip 30 described below is fitted.

Next, the valve mechanisms of the A and B systems will be explained. The valve mechanism of the A system has a tip head facing the end of the balance piston 7, and a small diameter portion of the rear end that fits into the blind hole cylinder 3. A control piston 10 that is fitted together, a control spring 12 that presses the control piston 10 toward the distal end, and a control spring 12 that presses the control piston 10 toward the distal end.
The input/output liquid chambers a ₁ , a ₂ are fitted loosely into the shaft of the A system chamber.
and a valve seat 11 which cooperates with a valve body portion 10' formed at the top end of the control piston 10 to form a proportioning type active valve mechanism. The valve seat 11 is pressed against the end of the fail-safe piston 5 via a backup 15 by the spring force of a hold spring 14. 16,17,1
8 is the spring seat, 19 is the piston cup, 20
indicates input liquid chamber _a1 and A-system master cylinder (not shown)
Input port 21 connects the same input liquid chamber A ₁ to A
The output port 22 connects to the system front wheel brake system (not shown), and is an output port that connects the output liquid chamber _a2 to the A system rear wheel brake system (not shown).

The operation of such a valve mechanism is known, and the seal cross-sectional area of the valve body 10' is A ₁ , the cross-sectional area of the blind hole cylinder 3 is A ₂ , the spring force of the control spring 12 is F, and the input and The hydraulic pressure in the output liquid chambers a ₁ and a ₂ is Pa ₁ ,
If Pa ₂ , then Pc (= Pa ₁ , Pa ₂ ) = F/A ₂ At the corner value Pc, the control piston 10 starts moving to the left in the figure, and the valve body 10' comes into contact with the valve seat 13. Then, the communication between the input and output liquid chambers _{a1 and a2} is closed, and after this, the output liquid pressure _Pa2 is relaxed relative to the input liquid pressure _Pa1 at an angle of tanθ=( _A1 − _A2 )/ _A1 . raise. Furthermore, if A ₁ =A ₂ is set, the valve mechanism becomes a limiting operation type.

On the other hand, in the B-system driven valve mechanism, a valve seat 24 assembled inside the cylinder of the fail-safe piston 5' divides the B-system chamber into input and output liquid chambers b ₁ and b ₂ , and the balance piston 7 The valve body portion 8 is configured to come into close contact with the valve seat 24 due to the movement, thereby controlling opening and closing of communication between the input and output liquid chambers b ₁ and b ₂ . That is, the valve body portion 8 of the balance piston 7 is provided so as to have the same sealing cross-sectional area A3 as the middle cylinder 6 with which the balance piston 7 is slidably engaged, and therefore the hydraulic action is controlled by _A3 in the left-right direction in the figure. The system moves so that the system output hydraulic pressure Pa ₂ and the B system output liquid chamber Pb ₂ are balanced, and as the A system hydraulic pressure control starts, the A system output hydraulic pressure Pa ₂ changes to the A system input hydraulic pressure.
When the pressure is reduced relative to Pa ₁ (same as B system input hydraulic pressure Pb ₁ ), the balance piston 7 moves to the left in the figure, and the valve body 8 comes into contact with the valve seat 24 to open the input/output liquid chamber. The communication between b ₁ and b ₂ is closed, and after this, the A and B system output hydraulic pressures Pa ₂ and Pb ₂ are increased to the same pressure. 25 is a hold spring for the valve seat 24, 26 is a spring seat, 27 is an input port that connects the input fluid chamber b ₁ to the B system master cylinder, and 28 is the input port that connects the input fluid chamber b ₁ to the B system master cylinder.
Output port connected to system front wheel brake system, 29
is an output port that connects the output fluid chamber _b2 to the B-series rear wheel brake system.

A feature of the present invention is that the control piston 10 and the balance piston 7, which constitute the valve mechanisms of the A and B systems as described above, are connected via a failsafe clip 30, so that relative separation can be achieved as will be described later. The control piston 10 is provided so as to be regulated to a related value, and the control piston 10 is configured to abut against the fail-safe piston 5 via the fail-safe clip 30. That is, as shown in FIGS. 2A and 2B, the fail-safe clip 30 includes a semi-cylindrical arc portion 30a, bending arms 30b extending tangentially from both ends of the arc portion, and arc-shaped The portion 30a is provided with semi-annular flange portions 30c, 30c bent along both side edges, one of the flange portions 30c is fitted into the circumferential groove 20 formed at the tip head of the control piston 10, and One of the flange portions 30c is loosely fitted into the circumferential groove 9 of the balance piston 7, and the bending arms 30b are bent radially inward to prevent them from coming off.

In the hydraulic pressure control device for double piping having the above-described configuration, in the normally shown stationary state, the control piston 10 is connected to the fail-safe pistons 5 and 5 via the fail-safe clip 30 by the spring force of the control spring 12. ', and the balance piston 7 is also biased by the control piston 10, so that the valve mechanisms of the A and B systems are connected to the input and output liquid chambers _a1 ,
A communication path between a ₂ and b ₁ and b ₂ is opened.

After this, when hydraulic pressure is transmitted, the control piston 10
moves against the control spring 12 and starts hydraulic pressure control of system A, and in conjunction with this, hydraulic pressure control of system B is also performed. At this time, the fail-safe pistons 5, 5' remain stationary due to the small spring force of the hold spring 14. If the amount of movement of the control piston 10 of the A-system valve mechanism is l ₂ and the amount of movement of the balance piston 7 is l ₃ , then l ₁ >l ₂ −l with respect to the loose fitting amount l ₁ of the fail-safe clip 30. It is necessary to set the relationship as ₃ .

By having this relationship, the fail-safe clip 30 and the circumferential groove 9 of the balance piston 7 do not engage, and the valve body parts 10', 8 and the valve seats 11, 24 engage simultaneously. sell.

When the B system fails, the balance piston 7 is moved to the right in the figure by the hydraulic pressure from the A system, so the fail-safe clip 30 and the circumferential groove 9 of the balance piston 7 engage, and the control piston 10 is restricted to the left side of the valve seat 11 in the figure, the hydraulic pressure control by the valve mechanism of the A system is released, and the input and output liquid chambers a ₁ and a ₂ always maintain communication.

In addition, when system A fails, the balance piston 7 and fail-safe pistons 5, 5' move to the left in the diagram due to the hydraulic action from system B, and they maintain the relationship shown in the diagram with respect to the control piston. , the control piston 10 hits the bottom of the blind bore cylinder 3 and is stopped. Therefore, the valve body 8 in the B-system driven type valve mechanism cannot come into contact with the valve seat 24, and the input and output liquid chambers b ₁ and b ₂ always maintain communication.

As described above, the hydraulic pressure control device for double piping according to the present invention has a relatively simple configuration, and cancels the valve operation of the normal system in the event of a failure of one system to increase the output hydraulic pressure, that is, the rear wheel brake. A sufficient increase in hydraulic pressure can be obtained, and the practical benefits thereof are extremely large.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a hydraulic control device, and FIGS. 2A and 2B show a fail-safe clip. FIG. 1... Valve body, 2, 2'... Valve cylinder, 3... Blind hole cylinder, 4... Plug, 5,
5'... Fail-safe piston, 6... Middle cylinder, 7... Balance piston, 8... Valve body part,
9... Circumferential groove, 10... Control piston, 11... Valve seat, 12... Control spring, 13...
Spring seat, 14...Hold spring, 1
5... Backup, 16, 17, 18... Spring seat, 19... Piston cup, 20... Circumferential groove, 21... Input port, 22, 23... Output port, 24... Valve seat, 25... Hold spring, 26... Spring seat, 27... Input port, 28, 29... Output port, 30...
Fail-safe clip, 30a... arcuate portion, 3
0b...Bending arm part, 30c...Flange part.

Claims (1)

[Claims] 1. A cylindrical fail-safe piston that is slidably fitted to a valve cylinder, and a balance piston that is slidably fitted to a middle cylinder inside the cylinder of this fail-safe piston and that divides the valve chamber into left and right A and B system liquid chambers. , the A system is turned on and off by the operation of a control piston that is disposed in the A system liquid chamber and moves backward from the balance piston against the biasing spring force due to hydraulic action.
A pressure reduction control type valve mechanism that controls the opening and closing of the output liquid chambers _a1 and _a2 , and a balance piston that moves toward the control piston that is arranged in the B system liquid chamber and balances the liquid pressure of the A and B system output liquid chambers. By moving, the input/output liquid chamber of B system
In a hydraulic pressure control device for double piping equipped with a driven type valve mechanism that controls the opening and closing of b ₁ and b ₂ , the control piston and the balance piston are fitted and fixed to the control piston between opposing parts, and the latter is fitted and fixed to the control piston. A fail that loosely fits into the balance piston to regulate the left and right separation limits of both of them to a constant value, and stops movement of the control piston due to the action of the biasing spring force by abutting against the fail safe piston. Install a safety clip and further increase the left and right separation limits mentioned above.
l ₁ , the amount of movement of the control piston to control the opening and closing of the valve mechanism is l ₂ , and the amount of movement of the balance piston to control the opening and closing of the valve mechanism is l ₃ , then these are l ₁ > l ₂ − _{l 3}
A hydraulic pressure control device for double piping, characterized in that it is configured to have the following relationship.