JPS637984B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double piping master cylinder having a built-in hydraulic pressure control valve for use in a vehicle brake system.

It has long been known that when braking a vehicle, it is necessary to reduce the brake force on the rear wheels at a constant rate compared to the front wheels. Hydraulic pressure control devices such as proportioning valves that control gradual rise are provided.

In addition, when the brake fluid system is made into a double piping type to improve the safety of vehicle braking, various improvements have been made in which the hydraulic pressure control of one system is linked to the other system between these two independent systems. has been done.

By the way, since such a hydraulic pressure control device is ultimately installed between the piping leading from the hydraulic pressure source to each brake device, it is possible to attach a control mechanism to the master cylinder as the hydraulic pressure source. For example, there is an advantage in reducing the weight and size of the device based on the common use of cylinder bodies, etc., and from this point of view, the present invention has the following advantages:
A control valve is installed at the hydraulic pressure supply port of the master cylinder to the rear wheel brake system, and when a failure occurs in one system of double piping, the operation of the control valve in the normal system is canceled and the pressure is supplied to the rear wheel side. It is an object of the present invention to provide a double piping master cylinder which can compensate for insufficient braking force by transmitting the same brake fluid pressure as that on the front wheel side to a brake device.

As a master cylinder for double piping for this purpose, one of the previously proposed master cylinders is Japanese Patent Application Laid-Open No.
There is one described in No. 146775. However, in this conventionally proposed master cylinder, if one brake hydraulic system fails, hydraulic control of the normal brake hydraulic system is canceled, but both the balance piston and the control piston The problem is that there is a lot of ineffective brake fluid consumption caused by the movement of brake fluid.

Therefore, the present invention provides a double piping master cylinder that can reduce ineffective brake fluid consumption in such cases.

That is, the feature of the double-piped master cylinder with a built-in hydraulic pressure control valve according to the present invention is that by applying an external force, hydraulic pressure is generated in two independent chambers, and the hydraulic pressure is transmitted to the corresponding front wheel brake device. and a fluid port for supplying hydraulic pressure from each of the two independent chambers of the main body to the corresponding rear wheel brake device. A hydraulic pressure control valve that controls the supply hydraulic pressure to slowly increase at a turning point and the hydraulic pressure of the two independent chamber systems in the main body are in balance, and the system is stopped, and when one system fails, the normal hydraulic system is stopped. The hydraulic pressure control valve is equipped with a compensation mechanism that uses a balance piston that moves under pressure to release the normal hydraulic pressure control valve, and the hydraulic pressure control valve is operated by the difference in hydraulic pressure acting on end surfaces of different areas at both ends of the shaft. a stepped piston that moves toward the smaller diameter side; a valve body that cooperates with the moving stepped piston to control the hydraulic pressure supplied to the rear wheel brake device to gradually rise at the corner point; A fluid chamber that faces a shoulder and is independent from a system for supplying fluid pressure to the rear wheel brake device, and when the fluid pressure of the fluid chamber is sealed, the stepped piston moves toward the small diameter side. the compensation mechanism includes a normally open flow path connected to release the liquid pressure of the stepped liquid chamber to a reservoir; and an independent fluid chamber of the main body. A flow path that is linked to a balance piston that moves when one system of the two chambers fails, and that moves the balance piston to close the normally open flow path and seal the liquid pressure in the stepped liquid chamber. It is configured to include a circuit closing means.

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

In the figure, 1 is the cylinder body of the master cylinder, which includes a main body in which the cylinder 2 is formed, reservoirs 3 ₁ , 3 ₂ in the upper part, hydraulic control valve built-in parts 4 ₁ , 4 ₂ and a built-in compensation mechanism in the lower part. It consists of part 5. The structure of the main body is almost the same as that of an existing tandem master cylinder, and includes a pair of primary and secondary pistons 6, 7 that are slidably fitted into the cylinder 2, and these pistons 6, 7 are moved in the direction in which external force is applied as shown by the arrows in the figure. a pair of return springs 8 and 9 that press in opposite directions; a piston cup 10 that seals the sliding surfaces of the two independent hydraulic pressure chambers a ₁ and a ₂ and the pistons 6 and 7 and the cylinder 2; The compensating ports 11 ₁ , 11 ₂ and the intake ports 12 ₁ , 12 ₂ connected to the liquid chambers a ₁ , _a 2 and the reservoirs 3 ₁ , 3 ₂ and the pair of pistons 6 , 7 are prevented from coming close to each other. It is comprised of a bolt 13 that prevents an increase in pedal stroke in the event of a system failure.

The operation is such that when the primary piston 6 is moved to the left in the figure in the cylinder 2 by the application of an external force F, the secondary piston 7 is also moved to the left in the figure by the hydraulic pressure in the liquid chamber _A1 and the balance between the return springs 8 and 9. Therefore, approximately the same hydraulic pressure is generated in the liquid chamber _a2 .

Reference numerals 14 ₁ and 14 ₂ are fluid ports that supply the fluid pressure of these fluid chambers a ₁ and a ₂ to the front wheel brake device.

Numerals 15 ₁ and 15 ₂ are liquid ports that supply hydraulic pressure to the rear wheel brake equipment, and hydraulic pressure control valves built in the front stage of the liquid ports 15 ₁ and 15 ₂ are constructed as follows.

16 ₁ , 16 ₂ are plugs forming the liquid ports 15 ₁ , 15 ₂ , 17 ₁ , 17 ₂ are cylinders formed at the inner ends of the plugs, and 18 ₁ , 18 ₂ are the cylinders 17 1 , 17 ₂ .
It is a stepped piston that is slidably fitted to the piston 17 ₂ , and vertical flow passages 19 ₁ , 19 ₂ are bored through the shaft portion, and piston cups 20 ₁ , 20 ₂ are assembled to the small diameter portion. The stepped portion liquid chambers b ₁ , b ₂ (hereinafter simply referred to as liquid chambers b ₁ , b ₂ ) of the stepped pistons 18 ₁ , 18 ₂ are connected to the liquid flowing from the liquid chambers a ₁ , a ₂ to the rear wheel side brake device. It is separated from the pressure system based on pressure. The stepped pistons 18 ₁ , 18 ₂ have a difference in the hydraulic pressure acting area between the small diameter end faces facing the liquid chambers a ₁ and a ₂ side and the large diameter end faces facing the liquid ports 15 ₁ and 15 ₂ side, and the stepped pistons 18 1 , 18 2 . Piston 18 ₁ ,
Due to the relationship between the spring forces of the control springs _{21 1 and} 21 2 that press and bias the control springs 21 1 and 21 ₂ toward the large diameter end, when brake fluid pressure is applied, the springs of the control springs 21 ₁ and 21 ₂ increase as the fluid pressure increases. The vertical flow passages 19 ₁ , 19 ₂ are moved to the small diameter end side against the force, and the upper diameter end side openings of the vertical flow passages 19 1 , 19 2 cooperate with the valve bodies 21 ₁ , 22 ₂ to open the vertical flow passages 19 ₁ , 19 2 .
19 ₂ is provided so that it can be opened and closed.

In the hydraulic pressure control valve having such a configuration, when hydraulic pressure is generated in each of the liquid chambers a ₁ and a ₂ of the main cylinder body 2, this hydraulic pressure is initially transferred to the vertical flow paths 19 ₁ , 19 ₂ , It is transmitted to the rear wheel brake device via the fluid ports 15 ₁ and 15 ₂ , and as this fluid pressure increases, the stepped piston 1
By moving 8 ₁ , 18 ₂ toward the small diameter end side, the valve body 22 ₁ ,
22 _{2 ,} the stepped piston ₁₈ The liquid chambers b ₁ , b ₂ in the stepped shoulders of ₁ , 18 ₂ are always in communication with the reservoirs 3 ₁ , 3 ₂ via the flow paths 23 ₁ , 23 ₂ , the compensation mechanism 5 and the intake ports 12 ₁ , 12 ₂ , respectively. and is placed in a state of zero hydraulic pressure.

The liquid chambers b ₁ and b ₂ are two independent hydraulic systems.
It is provided so that when one of A ₁ and A ₂ fails, the normal system side is sealed off from communicating with the reservoir 3 ₁ or 3 ₂ by the operation of the compensation mechanism 2. It is configured to restrict the movement of the pistons 18 ₁ and 18 ₂ to release the control valve.

That is, the compensation mechanism 5 includes a cylinder 24 in which a balance piston 25 and a follower piston 26 that can follow the balance piston 26 are slidably fitted together, and the balance piston 25 has a fluid chamber on both end surfaces thereof that generates brake fluid pressure.
It is provided so that the hydraulic pressure of a ₁ and a ₂ acts on it.
When the hydraulic pressures acting on both ends of the balance piston 25 are equal, the balance piston 25 remains stationary and communicates the liquid chambers b ₁ and b ₂ of each hydraulic pressure control valve with the reservoirs 3 ₁ and 3 ₂ , and when the hydraulic pressure in one system fails The balance piston 25 is provided so as to be pushed toward the failure side and cut off communication from the liquid chambers b ₁ and b ₂ of the normal system to the reservoirs 3 ₁ and 3 ₂ . 27 ₁ and 27 ₂ are the liquid chambers of the hydraulic pressure control valve
This is a seal that serves as a flow path closing means for blocking the flow path connecting and communicating b ₁ and b ₂ with the reservoir, and the seal is shut off by fitting into the small diameter portion of the cylinder 24 by movement of the balance piston 25 or follower piston 26. configured to perform an action.

Reference numeral 28 denotes an abnormality detection switch that detects movement of the balance piston 25 in either axial direction and activates a warning device (not shown).

In the double piping master cylinder with a built-in hydraulic pressure control valve configured as described above, under normal conditions, the hydraulic pressure generated in the main body's liquid chambers a ₁ and a ₂ due to the application of external force is applied to the front wheel brake system. The liquid is supplied as it is through the liquid ports 14 ₁ and 14 ₂ , and the liquid is supplied to the front wheel brake system through the liquid port 15 under gradual rising control at the corner point by the hydraulic pressure control valve.
It is supplied to the rear wheel brake system via ₁ , 15 _{and 2} .

When hydraulic pressure in one system fails, the normal hydraulic pressure can be supplied to the front and rear brake systems as is. That is, when the _A1 system loses hydraulic pressure, the balance piston 25 moves to the right in the figure ( _A1 system side) due to the hydraulic pressure action of the _A2 system, so the seal ₂₇₂ fits into the small diameter part of the cylinder 24. By blocking the communication of the flow path 23 ₂ with the reservoir 3 ₂ and sealing the liquid chamber b ₂ , the movement of the stepped piston 18 ₂ is restricted, and the liquid caused by the opening and closing operations of the vertical flow path 19 ₂ is prevented. Release pressure control. On the other hand, when the _A2 system loses hydraulic pressure, the balance piston 25 moves to the left in the figure ( _A2 system side), so the follower piston 26 is accompanied by this movement, and the seal 2
7 ₁ is fitted into the small diameter portion of the cylinder 24 and seals the liquid chamber b ₁ , thereby forming the stepped piston 1 in the same manner as above.
This is to restrict the movement of 8 ₁ and release hydraulic pressure control.

As described above, the master cylinder of the present invention has a built-in hydraulic pressure control valve, and when one system of double piping fails, the hydraulic pressure control of the normal system is canceled, so that the front and rear brake devices of the normal system are This has the effect of transmitting the same hydraulic pressure and compensating for the lack of braking force throughout the vehicle.Also, when one system fails, the movement of the stepped piston that controls the normal system hydraulic pressure can be restrained, so the brake fluid The amount of wasteful consumption is small, and the benefits are extremely large.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of a master cylinder showing an embodiment of the present invention. 1...Cylinder body, 2...Cylinder, 3 ₁ ,
3 ₂ ... Reservoir, 4 ₁ , 4 ₂ ... Hydraulic pressure control valve built-in part, 5 ... Compensation mechanism built-in part, 6 ... Primary piston, 7 ... Secondary piston, 8, 9 ...
Return spring, 10...Piston cup,
11 ₁ , 11 ₂ ...Competitive port, 12
₁ , 12 ₂ ... Intake port, 13 ... Bolt, 14 ₁ , 14 ₂ ... Liquid port, 15 ₁ , 15 ₂ ... Liquid port, 16 ₁ , 16 ₂ ... Plug, 17 ₁ , 17 ₂ ...
Cylinder, 18 ₁ , 18 ₂ ... Stepped piston, 19
₁ , 19 ₂ ... Vertical flow path, 20 ₁ , 20 ₂ ... Piston cup, 21 ₁ , 21 ₂ ... Control spring, 22
₁ , 22 ₂ ... Valve body, 23 ₁ , 23 ₂ ... Channel, 24
... Cylinder, 25 ... Balance piston, 26
...Following piston, 27 ₁ , 27 ₂ ...Seal.

Claims (1)

[Claims] 1 A main body of a master cylinder that generates hydraulic pressure in two independent chambers by applying an external force and supplies the hydraulic pressure to the corresponding front wheel brake device, and a hydraulic pressure that corresponds from each of the two independent chambers of the main body. a hydraulic pressure control valve that is disposed at each of the liquid ports that supply hydraulic pressure to the rear wheel brake device and controls the hydraulic pressure supplied to the rear wheel brake device to slowly increase at a turning point; When the hydraulic pressure values of the two-chamber system are balanced, the valve remains stationary, and when one system fails, the balance piston moves with the hydraulic pressure of the normal system, releasing the operation of the hydraulic pressure control valve of the normal system. The hydraulic pressure control valve has a stepped piston that moves toward a smaller diameter side due to a difference in hydraulic pressure acting on end surfaces of different areas at both ends of the shaft, and a compensation mechanism that cooperates with the moving stepped piston. A valve body that controls the hydraulic pressure supplied to the rear wheel brake device to slowly increase at the turning point, and a system that faces the stepped shoulder of the stepped piston and supplies hydraulic pressure to the rear wheel brake device. It has a stepped part liquid chamber which is an independent liquid chamber and restrains the movement of the stepped piston toward the small diameter side when the liquid chamber is hydraulically sealed; A normally open flow path connected to release the liquid pressure in the liquid chamber to the reservoir, and a balance piston that moves when one of the two independent chambers in the main body fails, are connected to the balance piston. A double piping master equipped with a built-in hydraulic pressure control valve, characterized by having a flow passage closing means for closing the normally open flow passage and sealing the liquid pressure in the stepped part liquid chamber by the movement of a piston. Cylinder.