JPH0143659B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control valve for two-system piping used in a two-system hydraulic brake system of an automobile.

A car's hydraulic brake system brakes the front and rear wheels at the same time, but at this time, the weight of the vehicle moves forward, reducing the load on the rear wheels and reducing the frictional force between the rear wheels and the road surface. The front wheels are easier to lock than the front wheels. By the way, if the rear wheels lock first, the car will experience a swaying phenomenon called skid, which is dangerous. Therefore, in a general hydraulic brake device, a hydraulic pressure control valve is usually inserted into the hydraulic pressure circuit facing the wheel cylinder of the rear wheel. This hydraulic pressure control valve does not directly supply master cylinder hydraulic pressure to the rear wheel cylinders, but responds to and limits this master cylinder hydraulic pressure (inlet hydraulic pressure) and uses it as outlet hydraulic pressure. is supplied to the rear wheel cylinder as rear brake fluid pressure.

On the other hand, as a hydraulic brake system for automobiles, a two-system hydraulic brake system is widely used today for safety reasons, which is divided into two systems so that even if one system fails, braking can be performed by the other system. This type of safety brake system uses a tandem master cylinder as a master cylinder that converts the force applied to the brake pedal into hydraulic pressure, and the master cylinder hydraulic pressure from one of the hydraulic pressure outlets is applied to the wheel cylinders of the left front wheel and the right rear wheel. In addition, there is a so-called X pipe that is divided into two to supply the master cylinder hydraulic pressure from the other hydraulic pressure outlet to the wheel cylinders of the right front wheel and the left rear wheel, respectively, and other pipes that are called J-J piping. It has been put into practical use.

However, no matter which of these piping systems is adopted, a two-system hydraulic brake system requires two of the above-mentioned hydraulic pressure control valves, and these hydraulic pressure control valves are required due to installation space and cost constraints. For related reasons, hydraulic control valves for dual-line piping housed in a single housing are being put into practical use.

However, conventional hydraulic control valves for dual-system piping are completed by sequentially assembling the parts of each hydraulic control valve into the corresponding holes in the housing, and after such assembly, performance tests are performed on each hydraulic pressure control valve. When it was determined that the valve was defective, the defective hydraulic control valve had to be disassembled by reversing the procedure used to assemble it, which took a lot of effort. Furthermore, when integrating the conventional two-line piping hydraulic control valve into a tandem master cylinder,
After assembling and testing each hydraulic pressure control valve, if it is determined that it is a defective product, the hydraulic control valve must be disassembled as described above.
In addition to being troublesome to remove, when testing each hydraulic pressure control valve, it is impossible to test each hydraulic pressure control valve individually while it is removed from the master cylinder, and it is necessary to test the tandem master cylinder as an integral part. Unavoidably, the test was extremely time-consuming.

The present invention involves preassembling all of the components of each hydraulic control valve into individual valve bodies, inserting the valve bodies into a common hole in the housing, and inserting both hydraulic control valves into the housing. From the viewpoint that if they are arranged coaxially in abutting relationship, each hydraulic pressure control valve can be integrated into a unit, and the various problems mentioned above can be solved at once, we have attempted to provide a hydraulic pressure control valve for two-system piping that embodies this idea. It is something to do.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

The drawing shows a preferred example in which the hydraulic pressure control valve for two-system piping according to the present invention is integrated into a tandem master cylinder. The pressure control valves are shown respectively. The cylinder body 1 houses a secondary piston and a primary piston (both not shown) that are slidably fitted into the bore 1a of the cylinder body 1, and together with these pistons constitutes a tandem master cylinder. This tandem master cylinder is a normal one which simultaneously outputs the same value of master cylinder hydraulic pressure P _n from the corresponding hydraulic pressure outlets 1b and 1c when both pistons respond to depression of the brake pedal.

The cylinder body 1 further has a valve housing 3 integrally formed on one side thereof, and the hydraulic pressure control valve 2 for dual-system piping of the present invention is assembled into the hole 3a of the housing 3. This two-system piping hydraulic pressure control valve 2 includes two hydraulic pressure control valves 4, 4' as a set, and these hydraulic pressure control valves 4,
4' is placed in the common hole 3a of the housing 3.
The respective hydraulic pressure control valves 4 and 4' are arranged in a coaxial abutting relationship with their directions facing opposite to each other, but in order to keep the structure and dimensions of each part exactly the same, only the hydraulic pressure control valve 4 will be explained below. As for the hydraulic pressure control valve 4', corresponding parts are only shown with the same reference numerals with dashes attached.

The hydraulic control valve 4 comprises a valve body 5, into which valve components are sequentially preassembled as follows.
That is, first, the pressure regulating piston 6 is slidably fitted in the vicinity of the closed end of the valve body 5 to define the outlet chamber 7, and the retainer 8 and the seal 9 in which the pressure regulating piston 6 is fitted into the valve body 5 are fitted. is guided in the axial direction under liquid-tight sealing. Note that the pressure regulating piston 6 has a stop flange 6a.
is provided, and when this collides with the retainer 8, the amount of axial movement of the pressure regulating piston 6 is limited to _L1 . Further, the open end of the valve body 5 is closed by a plug 10 to define an inlet chamber 11 between the valve body 5 and the seal 9, and a spring seat 12 is slidably fitted into the plug 10. A valve body 13 is hooked onto the end of the spring seat 12 facing the seal 9, and the valve body is resiliently supported by a spring 14 at the position shown in the figure closest to the seal 9. A valve seat 15 for the valve body 13 is fixed to the pressure regulating piston 6, and a spring 16 is compressed between the valve seat 15 and the spring seat 12, so that the stop flange 12a provided on the spring seat 12 and the plug 10 are connected to each other. In the illustrated state where a gap L ₂ exists between them, a gap L ₃ corresponding to the valve lift amount is created between the valve body 13 and the valve seat 15. In addition, the gap L ₁ ,
Between L ₂ and L _3, L ₃ < L ₁ so that the effect described below can be obtained.
Set the relationship <L ₂ +L ₃ . The valve body 13 further includes a valve rod 17 whose one end can come into contact with the closed end of the valve body 5.
This valve stem is loosely inserted into the hollow hole of the pressure regulating piston 6, and a hydraulic pressure passage 18 is established between the two.

The hydraulic pressure control valves 4, 4' having the above-mentioned configuration are preassembled into the respective valve bodies 5, 5', and then
First, insert the valve body 5 into the housing hole 3 from its closed end side.
a into the housing hole 3a, and then insert the valve body 5' from its open end into the housing hole 3a and abut the plug 10' against the housing hole 3a. Incorporate. By maintaining this state with a plug 19 screwed onto the open end of the housing hole 3a, both hydraulic pressure control valves 4,
4' can be held in coaxial butting relationship within housing bore 3a.

Also, in the assembled state of this hydraulic pressure control valve 4, 4',
The valve bodies 5, 5' are provided with grooves 5a, 5'a and ports 5b, 5'b which communicate the hydraulic outlets 1b, 1c with the inlet chambers 11, 11'.
Ports 3b and 3c are formed in the housing 3 to directly take out the master cylinder hydraulic pressure _Pn that has reached the grooves 5a and 5'a from the port 3c. The valve bodies 5, 5' are further provided with ports 5c, 5'c communicating with the outlet chambers 7, 7', and ports 3d, 3e communicating with these ports are formed in the housing 3.

When the hydraulic pressure control valve for two-system piping of the present invention configured as described above is used in a two-system hydraulic brake system with X piping of an automobile, port 3b is connected to the wheel cylinder of the left front wheel, and port 3c is connected to the right front wheel. For practical use, the port 3d is connected to the right rear wheel cylinder, and the port 3e is connected to the left rear wheel cylinder, respectively, and the operation is as follows.

The drawing shows both hydraulic control valves 4, 4' in the inoperative state. When the driver depresses the brake pedal to brake the vehicle, the tandem master cylinder outputs master cylinder hydraulic pressure P _n from the outlets 1b and 1c. The hydraulic pressure P _n from the outlets 1b and 1c is supplied to the inlet chambers 11 and 11', and since the ports 3b and 3c are always in communication with these inlet chambers, the hydraulic pressure P _n of both master cylinders is directly supplied to these ports. It reaches the left and right front wheel cylinders and brakes the left and right front wheels. On the other hand, the hydraulic pressure P _n that has reached the inlet chambers 11, 11' is initially at the open position where the valve bodies 13, 13' are away from the valve seats 15, 15', respectively.
Passage 18, 18', outlet chamber 7, 7', port 5c,
5'c and ports 3d and 3e, it is directly supplied to the wheel cylinders of the corresponding right and left rear wheels, and brakes these rear wheels.

By the way, the pressure regulating pistons 6 and 6' have different pressure receiving areas at both ends, and the pressure receiving area facing the chambers 7 and 7' is larger than the pressure receiving area facing the chambers 11 and 11', so that the master cylinder fluid is The pressure P _n moves the valve seats 15, 15' against the springs 16, 16' in a direction toward the valve bodies 13, 13'. When the master cylinder hydraulic pressure P _n reaches a certain value (critical hydraulic pressure), the valve seats 15, 15' come into contact with the valve bodies 13, 13', cutting off the hydraulic pressure passages to both rear wheel cylinders. From this point onwards, the increase in hydraulic pressure P _r toward the rear wheel cylinder is restricted. In other words, since the valve seats 15, 15' are seated on the valve bodies 13, 13' at this time, the master cylinder hydraulic pressure P _n acts on the pressure receiving surfaces of the pressure regulating pistons 6, 6' facing the chambers 7, 7'. The rear wheel brake fluid pressure P _r is applied. Therefore,
When the master cylinder hydraulic pressure P _n subsequently increases,
This rising amount pushes back the pressure regulating pistons 6, 6',
The valve seats 15, 15' are separated from the valve bodies 13, 13' again. As a result, the pressure regulating piston 6 facing the chambers 7, 7',
The master cylinder hydraulic pressure P _n comes to act on the pressure receiving surface of the valve 6' again, and the pressure regulating pistons 6, 6' stroke again so that the valve seats 15, 15' are seated on the valve bodies 13, 13'. By repeating the above action, both hydraulic pressure control valves 4 and 4' generate rear wheel brake hydraulic pressure P _r which increases at a lower rate with respect to the increase in master cylinder hydraulic pressure P _n in the region above the above-mentioned critical hydraulic pressure. This is then supplied to the rear wheel cylinder.

Thus, the braking force of the rear wheels that are braked by being supplied with the limited rear wheel brake fluid pressure P _r as described above is smaller than the braking force of the front wheels that are braked by being supplied with the master cylinder fluid pressure P _{n as} is. When the rear wheel load is reduced during braking, it is possible to prevent the rear wheels from locking up first.

During the above operation, the spring seats 12 and 12' move integrally from the high pressure side to the low pressure side when the master cylinder hydraulic pressure reaching the inlet chambers 11 and 11' becomes unbalanced for some reason. The pressures in both inlet chambers are corrected to be balanced, and the front and rear brake fluid pressures of the system related to valve 4 and the front and rear brake fluid pressures of the system related to valve 4' are always kept equal, so that the behavior of the braking vehicle body is maintained. prevent it from becoming stable.

Note that if one system, for example the system related to valve 4', fails, the hydraulic pressure P _n will not be generated in this system, so
Master cylinder hydraulic pressure P _n from outlet 1b during braking
Push the spring seat 12 by a gap _L2 . On the other hand, this master cylinder hydraulic pressure P _n pushes the pressure regulating piston 6 toward the valve body 13 as described above, but since L ₁ < L ₂ + L ₃ as described above, the valve seat 15 is such that the piston 6 is at its maximum. Even if the stroke is limited to L ₁ , the valve seat 13
The hydraulic pressure control valve 4 of the normal system is normally open, and the master cylinder hydraulic pressure P _n is directly output from the port 3d. Therefore, when one system fails, the valves 4 in the normal system do not perform the hydraulic pressure control, and it is possible to generate sufficient braking force with only one system.

Thus, in the hydraulic control valve for dual-system piping of the present invention, all the components of each valve 4, 4' are preassembled in the individual valve bodies 5, 5' as described above to form a unit, and the common hole of the housing 3 is assembled into a unit. Since the hole 3a is inserted coaxially into the hole 3a, the shape of the hole 3a is simple, and the processing thereof is simple and requires only one step, improving production efficiency. In addition, since each hydraulic pressure control valve 4, 4' is integrated into a unit, it is possible to test the performance of these valves before inserting them into the housing 3, detecting the occurrence of a defect in advance, and performing the test using hydraulic control. The work can be done with a single valve, which is easy to do, and even if the product is found to be defective after testing, only the valve can be used to discard it, which improves yield. Furthermore, even if the valves 4, 4' are found to be defective after being assembled into the housing 3, they can be easily and quickly taken out as a unit from the housing 3 and replaced with another valve, and the workability at this time is also very good. This effect becomes particularly noticeable when the valves 4, 4' are integrated with another object such as a master cylinder as shown in the illustrated example.

[Brief explanation of drawings]

The drawing is a longitudinal sectional side view of the hydraulic pressure control valve for two-system piping according to the present invention. 3... Housing, 3a... Hydraulic pressure control valve insertion hole, 4, 4'... Hydraulic pressure control valve, 5, 5'... Valve body, 6, 6'... Pressure regulating piston, 7, 7' ...Exit chamber, 8,8'...Retainer, 9,9'...Seal,
10,10'...Plug, 11,11'...Inlet chamber, 12,12'...Spring seat, 13,13'...Valve body, 14,14',16,16'...Spring, 15,
15'... Valve seat, 17, 17'... Valve stem, 18, 1
8'...Hydraulic pressure passage, 19...Plug.

Claims (1)

[Scope of Claims] 1. A spring and a pressure regulating piston that is applied with the inlet hydraulic pressure and the outlet hydraulic pressure in opposite directions, and the pressure regulating piston opens in response to the inlet hydraulic pressure and opens in response to the outlet hydraulic pressure. A set of two hydraulic pressure control valves is provided, which consists of a valve body and a valve seat assembly that close when the valve body closes, and which limits the inlet hydraulic pressure while controlling the outlet hydraulic pressure, and these hydraulic pressure control valves are housed in a single housing. In the hydraulic pressure control valve for two-system piping, the spring of each of the hydraulic pressure control valves, the pressure regulating piston,
Pre-assembling the valve body and valve seat assembly into individual valve bodies, inserting the valve bodies into a common hole in the housing, and coaxially coaxially positioning the hydraulic control valves within the housing in abutting relationship. Hydraulic pressure control valve for two pipe lines installed. 2. Both of the hydraulic pressure control valves are arranged so that when one system fails and the hydraulic pressure control valve related to this system is kept in an inoperable state, the hydraulic pressure control valve related to the other system is always opened even when activated. A hydraulic pressure control valve for two-system piping as set forth in claim 1 of the accompanying claims.