JPS5921091Y2 - Brake hydraulic pressure control valve - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a brake fluid pressure control valve used in a vehicle.

Many vehicles such as automobiles use hydraulic pressure for braking, but in general, when sudden braking is performed, the deceleration increases, causing load fluctuations between the front and rear wheels, making it easier for the rear wheels to lock up early.

Therefore, in order to safely stop a vehicle from high-speed driving, it is very important to adjust the ratio of braking force on the rear wheels to the front wheels depending on the magnitude of the load.

The brake fluid pressure control valve is provided in the middle of a pipe connecting the mask cylinder and the wheel cylinder, and is adapted to adjust the brake force as described above.

As a prior application relating to this type of brake fluid pressure control valve, there is Utility Model Application No. 46-91596 (Utility Model Publication No. 52-12867).

Now, in this prior application, a cylinder is inserted into a passage between a master cylinder and a rear wheel brake device, and has an inlet hole connected to the master cylinder and an outlet hole connected to the rear wheel brake device; A hollow piston is movably inserted and has a small pressure receiving surface facing the inlet hole and a large pressure receiving surface facing the outlet hole, and when the piston moves toward the small pressure receiving surface side, an opening on the small pressure receiving surface side is formed. A brake hydraulic control device comprising a valve seat that blocks the inlet hole and the outlet hole and blocks communication between the inlet hole and the outlet hole, and a spring that urges the piston in a direction away from the valve seat, the adjusting rod to which the valve seat is attached. is arranged coaxially with the piston and slidably protrudes from the adjacent end of the cylinder with a liquid seal, and an adjusting rod is screwed into the cylinder so that the screwing position can be adjusted arbitrarily from outside the cylinder. The braking force ratio can be adjusted from the outside because it has a configuration in which a knob is provided on the protruding end of the adjustment rod.

However, this prior application discloses a point (hereinafter referred to as a "cut point") at which to start applying the brake and adjusting the proportion of the braking force.

), the adjustment rod moves away from the operating end of the adjustment rod while still blocking the opening on the side of the small pressure receiving surface of the hollow piston.

Therefore, in this prior application, it is possible to change the cut point when the brake pedal is not actuated, but once the brake force is adjusted at a certain rate when the brake is applied, the cut point cannot be adjusted. Ta.

This invention provides a brake fluid pressure control valve that allows the cut point to be changed even during braking and after the fluid pressure adjustment has started from the cut point.

Next, one embodiment of this invention will be explained with reference to the diagram.
In the figure, 1 is a valve body, which is formed by joining two parts 2 and 3.

A connection port 4 is provided at the left end of the valve body 1, and is commonly connected to a mask cylinder and a front wheel cylinder (both not shown).

Further, near the center of the valve body 1, there is a connection port 5 that opens perpendicularly to the connection port 4, and a rear wheel cylinder (not shown) is connected to the connection port 5.

A stepped hole is bored inside one portion 2 of the valve body 1, and the left end thereof forms a small diameter cylinder 6 communicating with the aforementioned connection port 4.

Further, a chamber 7 consisting of two stepped holes is formed in communication with the small diameter cylinder 6.

A large diameter cylinder 8 is bored inside the other portion 3 of the valve body 1 and communicates with the aforementioned connection port 5, and the left end of this large diameter cylinder 8 opens into the aforementioned chamber 7.

These two cylinders 6.8 have a small diameter part 9 and a large diameter part 1.
One stepped piston 11 having a diameter of 0 is tightly and slidably fitted.

12.13 is O nong.

A washer 14 is fitted on the left side of the stepped portion of the large diameter portion 10 of the stepped piston 11, and a spring 16 is interposed between the washer 14 and one side portion 15 of the chamber 7.

The stepped piston 11 is always urged to the right in FIG. 1 by the spring 16.

A through hole 17 whose diameter is slightly larger on the large diameter portion 10 side is bored in the axial center of the stepped piston 11 .

A valve seat 19 having a passage 18 in the center is fitted on the right side of the through hole 17.

A ball valve 20 is provided inside this valve seat 19, and this valve 20 is always urged by a spring 21 in a direction in which it comes into contact with the valve seat 19.

On the right side of the valve body 1 opposite to the connection port 4, there is a boss 23 with a knob 22 attached thereto, and a male thread 24 carved on its circumferential surface.
An internal thread 25 carved into the end of one part 3 of the valve body 1
It is attached by screwing into the

An adjuster portion 26 is integrally provided on the boss 23 via a reduced diameter portion, and this adjuster portion 26 is connected to the O-ring 2.
7, it is tightly and slidably fitted into the large diameter cylinder 8.

A pin 28 having a smaller diameter than the passage 18 of the valve seat 19 is installed in the adjuster portion 26, and the pin 28 pushes the ball valve 20 to the left.

29 is a bolt for preventing the adjuster portion 26 from coming off.

By rotating the knob 22 using this hydraulic pressure control valve configured as described above, the valve 20 is set so as to be moved away from the valve seat 19 against the spring 21 as shown in FIG.

When the driver depresses the brake pedal in this state, fluid from the mask cylinder with a pressure corresponding to the depressing force on the brake pedal is connected from the connection port 4 through the small diameter cylinder 6, the through hole 17 of the stepped piston 11, and the passage 18. It flows to port 5 and operates the wheel cylinder of the rear wheel.

When the pressure inside the mask cylinder connected to the connection port 4 increases, the stepped piston 11 moves to the left in FIG. 1 against the spring 16 due to the difference in pressure receiving area between its left and right ends.

Due to this movement, the ball valve 20 and the valve seat 19 gradually come close to each other, and eventually the ball valve 20 is seated on the valve seat 19 and the passage 1 is closed.
8 will close late.

When the pressure inside the mask cylinder further increases from this state, the hydraulic pressure inside the small diameter cylinder 6 increases accordingly, and the force pushing the stepped piston 11 to the right increases, causing the stepped piston 11 to move as shown in FIG. Move to the right.

Even with this movement, the ball valve 20 is separated from the valve seat 19 because its movement to the right is restricted by the pin 28.
The passage 18 is opened again, and the hydraulic pressure from the mask cylinder flows into the wheel cylinder of the rear wheel, and the hydraulic pressure in the wheel cylinder increases somewhat.

At this time, the stepped piston 11 moves to the left again due to the hydraulic pressure applied to the difference in pressure receiving area between the left end and the right end of the stepped piston 11, and the passage 18 is eventually closed.

At this time, the increase in hydraulic pressure between the mask cylinder and the rear wheel cylinder is calculated as ΔPm,
If the increase in the hydraulic pressure of the wheel cylinder is ΔPw, the pressure receiving area on the small diameter side of the stepped piston is a, and the pressure receiving area on the large diameter side is A, then ΔPw - ΔΔPm is obtained.

In this way, as long as the hydraulic pressure on the mask cylinder side continues to rise, the balance between the pushing force of the spring 16 and the pushing force due to the differential pressure on the stepped piston 11 is maintained, and the hydraulic pressure on the wheel cylinder side of the rear wheel is kept constant. As we continue to rise,
As shown in line a in Figure 2, the rate of increase in hydraulic pressure after the inflection point A is gradual, and therefore the rate of increase in the hydraulic pressure through this control valve is gradual compared to the front wheel which is directly connected to the mask cylinder. The pressure will rise.

When the hydraulic pressure in the mask cylinder decreases during the driver's brake release process, while the pressure on the small diameter cylinder 6 side is higher than the pressure on the large diameter cylinder 8 side (until it reaches the line zero in Figure 2), , the ball valve 20 leaves the pin 28 while the ball valve 20 remains seated on the valve seat 19, and the stepped piston 11 compresses the spring 16 and moves to the left.

Therefore, the volume inside the large-diameter cylinder 8 increases, and the pressure on the large-diameter cylinder 8 side decreases by the amount of increase.

When the pressure on the small diameter cylinder 6 side becomes equal to the pressure on the large diameter cylinder 8 side, and the pressure on the small diameter cylinder 6 side further decreases, and the differential pressure between the left and right sides of the ball valve 20 becomes larger than the force of the spring 21, the ball valve 20 Due to the differential pressure, the valve seat 1
The fluid in the wheel cylinder of the rear wheel is returned from the connection port 4 to the mask cylinder side via the connection port 5, the passage 18, and the through hole 17.

The force of the spring 16 pushes the stepped piston 11 back to the right in FIG. The state returns to the state shown in FIG. 1 before the start of brake operation.

Next, rotate the knob 22 appropriately to connect the boss 23 and the valve body 1.
When the adjuster part 26 is advanced to the left in FIG. 1 by the screw connection, the pin 28 installed in the adjuster part 26 pushes the ball valve 20 to the left, so that the ball valve 20 and the valve The distance from the seat 19 increases, and the ball valve 2
The amount of compression of the spring increases until the valve seat 19 contacts the valve seat 19, and as a result, the inflection point of the increase in hydraulic pressure rises from A to B in Fig. 2, and the line of increase in hydraulic pressure at the rear wheel becomes as shown in b. Become.

Rotate the knob 22 in the opposite direction to move the ball valve 20 to the valve seat 19.
When the ball valve 20 is brought closer to the valve seat 19, the timing at which the ball valve 20 seats on the valve seat 19 becomes earlier, and the inflection point of the increase in fluid pressure falls to C in FIG.
At that time, the hydraulic pressure rise line will look like C.

In addition, with this invention, even when the hydraulic pressure of the mask cylinder is maintained constant, if the position of the pin 28 is changed together with the boss 23 by rotating the knob 22 at the appropriate time, the hydraulic pressure rises while the brake is still operating. can be changed to something higher than the current state.

That is, assume that the driver is pressing the brake pedal with a constant pedal force F1 shown in FIG. 3, and the wheel cylinder pressure of the rear wheel is Pa.

At this time, the ball valve 20 shown in FIG. 1 is in contact with the valve seat 19,
At the same time, it is also in contact with the pin 28.

From this position, when the knob 22 is rotated in a direction to raise the bending point and the boss 23 is displaced, the ball valve 20 moves to the valve seat 19.
The liquid flows from the mask cylinder to the wheel cylinder, increasing the pressure in the wheel cylinder.

Then, in a state balanced with the force of the spring, ball valve 2
0 closes.

As a result, the wheel cylinder pressure of the rear wheel becomes P in Figure 3.
By increasing the pressure from a to Pb and changing the position of the boss 23 while keeping the pedal force constant, the pressure in the wheel cylinder can be increased.

This type of operation involves continuing to drive with the hydraulic pressure rising line downward in the snowy area, crossing the watershed and entering the long descending road in the dry area, and halfway through the descending road becoming a dry paved road and moving upward. If you want to obtain a hydraulic pressure rising line of 1, you can change to the upper hydraulic pressure rising line while applying the brake without loosening the brake, which increases the reliability of the brake.

As described above, in this invention, one connection port 4 is connected to the mask cylinder and the other connection port 5 is connected to the rear wheel cylinder inside the valve body 1, and the one connection port 4 side is connected to the small diameter cylinder 6. In addition, the other connection port 5 side is connected to the large diameter cylinder 8.
A stepped hole formed in the two cylinders 6.8 is bored.
A stepped piston 11 that fits into these is slidably provided inside the stepped piston 11, and a spring 16 that urges the stepped piston 11 toward the large diameter cylinder 8 is provided. A through hole 17 is provided with a valve mechanism consisting of a valve 19 and a valve 20 energized in the closing direction, and a boss 23 is provided on one side of the valve body 1 so as to be movable forward and backward. A pin 28 is disposed at one end of the cylinder 8, that is, between the adjuster portion 26 and the valve 20, so that the valve 20 and the pin 28 come into contact when the mask cylinder hydraulic pressure and the force of the spring 16 are balanced. Since the braking force is configured to immediately adapt to changes in the fluid pressure of the mask cylinder, the braking force changes, and by changing the position of the boss 23 from the outside, the bending point of fluid pressure rise can be easily changed to the high pressure side while the brake is applied. This has the advantage of providing a highly reliable brake fluid pressure control valve.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of this invention, FIG. 2 is a working hydraulic pressure characteristic diagram, and FIG. 3 is an explanatory diagram of pressure changes when the hydraulic pressure rise line is raised. DESCRIPTION OF SYMBOLS 1... Valve body, 4, 5... Connection port, 6... Small diameter cylinder, 8... Large diameter cylinder, 9... Small diameter part of stepped piston, 10... Stepped piston Large diameter part, 11...
・Stepped piston, 16.21...Spring, 17・
...Through hole, 18...Passage, 19...Valve seat, 20.
... Ball valve, 22 ... Knob, 23 ... Boss, 2
4...Male thread, 25...Female thread, 28...Pin.

Claims (1)

[Scope of utility model registration request] Inside the valve body, one connection port is connected to the mask cylinder, the other connection port is connected to the rear wheel cylinder, one connection port is connected to the small diameter cylinder, and the other connection port is connected to the large diameter cylinder. the formed stepped holes are drilled, and stepped pistons are slidably provided in the two cylinders to fit into the small diameter cylinder and the large diameter cylinder, respectively, through the small diameter part and the large diameter part, A spring is provided that urges the stepped screw toward the large diameter cylinder, and the stepped piston is provided with a through hole that penetrates in the axial direction of the stepped piston. A □valve mechanism consisting of a valve biased by a spring against a valve seat is arranged such that the valve seat is located on the large diameter end opening side of the stepped piston of the through hole, and the large diameter of the valve body is One side connected to the cylinder is provided with a boss whose one end faces the large diameter portion of the stepped piston and whose other end projects outside the valve body so that it can move back and forth in a tight manner. A brake fluid pressure control valve characterized by being provided with a pin that changes the distance between the valve and the valve seat in response to directional displacement.