JPS62268761A - Variable load liquid pressure control valve - Google Patents

Abstract

PURPOSE:To secure the braking force when the external input disappears by inserting an internal spring energizing a piston in the opening direction at a predetermined time between a lever rotatively energized in response to the change of the vehicle height and the piston in a liquid pressure control valve with which this lever is brought into contact. CONSTITUTION:A lever 26 is rotatably fitted to a liquid pressure control valve main body 15 with a bolt 27, and a rod 28 provided at one end of this lever 26 is inserted into a chamber 24 formed between a piston 18 and a plug 23. An external spring 14 is inserted between the lever 26 and a link 13, with one end pivotally fitted to a vehicle body 11 and the other end fixed to an axle. Thereby, the lever 26 is rotatively energized in response to the change of the vehicle height. In this case, an internal spring 25 energizing the piston 18 in the opening direction until the input pressure when the vehicle is vacant reaches the cut pressure for the maximum use pressure is inserted between the lever 26 and piston 18, and the piston and lever 26 are energized in opposite directions to each other by this internal spring 25.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a variable load hydraulic pressure control valve provided in a brake system of an automobile.

(Conventional technology) Generally, when braking a car, the center of gravity shifts due to the inertia of the car body, and more load is applied to the front wheels. Therefore, when the same braking force is applied, the rear wheels are braked before the front wheels, making the vehicle's posture unstable. There was a risk that the rear wheels would lock up. Therefore, a hydraulic pressure control valve is provided in the rear wheel brake system to control the hydraulic pressure supplied to the rear wheel brake system. In addition, particularly in vehicles such as trucks whose loaded weight changes significantly, a variable load hydraulic pressure control valve is used that can adjust the brake fluid pressure to the rear wheels according to the loaded weight.

Conventionally, for example, there is a variable load hydraulic pressure control valve shown in FIGS. 3 and 4.

To explain the figure, an oil inlet 2 is provided in the hydraulic control valve body 1.
and an outflow port 3, and has a cylinder section 4 inside the main body 1 that communicates the inflow port 2 and the outflow port 3, and a piston 5 is slidably installed inside the cylinder section 4, and the piston 5 A liquid passage 6 is formed in which the inlet 2 and the outlet 3 communicate with each other. Further, a valve body 7 is disposed in the liquid passage 6, and as the piston 5 moves, a valve seat 8 formed at the end of the piston 5 comes into contact with the valve body 7, so that the liquid passage 6 can be closed. It looks like this. Further, the piston 5 is resiliently biased in the valve opening direction by an internal spring 9. Then, a lever 10 is pivoted to the main body l of the hydraulic pressure control valve configured in this way, one end of the lever 10 is engaged with the piston 5, and the other end is pivoted to the vehicle body 11 and the axle 12, respectively. Link 1
3 through an external spring 14.

Next, the operation related to the above configuration will be explained using FIG. 5.

When the brake of the vehicle is stepped on when the vehicle is piled up, the master cylinder hydraulic pressure (input hydraulic pressure) is transmitted from the demonstrator 2 through the flow path 6 in the piston 5 and from the outlet 3 to the rear wheel brake device. (Output hydraulic pressure) At this time, the piston 5 is in the open state due to the resilient bias of the internal spring 9 and the rotational bias of the lever 10 by the external spring 14, but if the brake is continued to be depressed, When the supplied hydraulic pressure increases and the pressure inside the flow passage 6 becomes greater than the biasing force, the piston 5
moves, and the valve body 7 is seated on the valve seat 8, closing the flow passage 6 and cutting off the supply of oil. (Cut point A) When the flow of oil is cut off, the pressure on the inlet z side increases and acts on the large diameter portion 5a of the piston 5, causing the piston 5 to move and the valve body 7 and valve seat 8 to move.
are separated from each other, and the oil is again supplied to the outlet 3 side through the flow path 6. In this way, the valve body 7 and the valve seat 8 are repeatedly separated and seated, and brake fluid pressure corresponding to the deceleration of the vehicle is supplied to the rear wheels (dynamic characteristics when empty).

Furthermore, when the vehicle is loaded with luggage, etc.,
Since the vehicle body 11 is lowered, the external spring 14 is stretched, and the rotational biasing force of the lever 1G increases, thereby shifting the cutting pressure upward. (Point B) That is, a large braking force can be obtained depending on the vehicle load. (Dynamic characteristics of vehicle a) In this way, the output hydraulic pressure is adjusted according to the vehicle's load according to the ideal distribution curve, and is transmitted to the rear wheel brake system, allowing for effective braking action. It is something that

In reality, when the vehicle is braked, the vehicle body 11 lifts up, so the external spring 14 is compressed by that amount, the rotation biasing force of the lever 10 is reduced, and the cutting pressure is shifted downward. For example, when the input hydraulic pressure is increased to 0 point in Figure 5, the intersection point (D point) is the cutting pressure.

(Problems to be Solved by the Invention) However, the variable load hydraulic pressure control valve having the above configuration has the following problems.

First, if the external spring 14, lever lO, etc. are damaged, there will be no external input and the piston 5 will be moved by the force of the internal spring 9 alone.
will be energized. Therefore, if the spring force is too small, the cutting pressure will be low and the brake force on the rear wheels will drop too much, resulting in a longer vehicle stopping distance.If the spring force is too large, the rear wheels may lock, which is dangerous. There was a problem.

In addition, in the above-mentioned configuration, if the vehicle rebounds due to unevenness on the road surface without any external input, such as when the external spring 14 has reached its free length, the external spring 14 becomes completely free, and the external spring 14 becomes completely free, preventing the body from getting caught in the body. There was a problem that there was a risk that the number 11 would drop out.

The present invention has been made in view of the above problems, and enables optimum braking force to be obtained even when no external input is applied.
Furthermore, the purpose is to securely hold the external spring 14.

(Means for solving the problem) As a means to solve the above problem and achieve the purpose, we installed a lever rotatably attached to the piston built into the main body of the hydraulic control valve. An external spring is stretched between the lever and a link whose one end is pivoted to the vehicle body and the other end is fixed to the axle, and the lever is applied to the lever via the external spring to respond to changes in vehicle height. In the variable load hydraulic pressure control valve that follows and applies rotational bias, the piston is moved in the valve opening direction until the input pressure when the vehicle is empty reaches a cut pressure with respect to the maximum operating pressure between the lever and the piston. An internal spring that can be biased toward the piston is provided, and the piston and the rod are resiliently biased in opposite directions.

(effect) The above configuration works as follows.

When the external input is lost, such as when the external spring or lever is damaged, the piston is biased by the internal spring that can bias the piston in the valve opening direction until the input pressure when the vehicle is empty reaches the cut pressure for the maximum working pressure. Ru.

In this way, when there is no external input, the operation is performed only by the internal spring, so the characteristic follows the static decompression heavy line shown in Figure 6, and the piston operates at the cut pressure point e relative to the maximum working pressure E. In addition, the rear wheels do not lock up, and the braking force does not decrease too much, ensuring braking power in ideal conditions.

Additionally, the internal spring biases the lever in the opposite direction as a reaction to the biasing force on the piston described above, thereby preventing the external spring from reaching its free length condition.

(Example) Next, an example of the present invention will be described based on the drawings. Note that the same members as in the prior art are given the same reference numerals.

FIG. 1 shows a longitudinal sectional view of the first embodiment, in which an inlet IB and an outlet 17 are provided in the hydraulic control valve main body 15, and an inlet 1B and an outlet 17 are provided inside. A cylinder portion 19 is formed which communicates with the piston 18 and allows the piston 18 to slide therein. A flow passage 20 that communicates the inlet 16 and the outlet 17 is provided in the piston 18, and a valve body 21 is disposed in the flow passage 20, so that as the piston 18 moves, The piston 18 is seated on a valve seat 22 attached to the outlet side of the flow passage 20 at one end of the piston 18 to close the flow passage 20. The other end of the piston 18 is a plug 23
A plate 18a is attached to a holder that protrudes into the room 24 defined by and receives an internal spring 25, which will be described later.

A lever 2B is rotatably pivoted to the hydraulic control valve body 15 at a port 27, and a rod 28 provided at one end of the lever 26 is inserted into the chamber 24. A spring seat 2 is provided between the tip of the rod 28 and the piston 18.
9 is provided, and the spring seat 29 is provided with a rod 28
A spring receiver 29a extends along the radial outer direction of the plate 18a, and the spring receiver 29a and the receiver of the piston 18 are connected to the plate 18a.
An internal spring 25 is interposed between the two. An external spring 14 is attached to the other end of the lever 26, and the external spring 14 is stretched between the link 13 connecting the vehicle body 11 and the axle (not shown) and the other end of the lever 2B. ing.

In the variable load hydraulic pressure control valve configured as above, the external spring 14
Alternatively, if the lever 26 is damaged by a flying stone or the like, there will be no external input from the rod 28 of the lever 26, and the piston 18 will be biased only by the internal spring 25. The characteristic at this time follows the static decompression heavy line from the cut point e shown in FIG. Furthermore, when the rod 28 comes off, the spring sheet 29 retreats to the end of the chamber 24, causing the internal spring 25 to expand and reduce the spring force; however, if the internal spring 25 is set to a small spring constant, the cutting pressure can be significantly reduced. can be prevented. Therefore, an appropriate amount of braking force can be obtained without causing insufficient or excessive braking force.

In addition, the external spring 14 is expanded and contracted by the link 13 according to the vehicle height, or the lever 2B is rotationally biased by the internal spring 25 via the rod 28, so that the external spring 14 is always under a load. , foreign objects will not get caught or fall off.

Next, FIG. 2 is a longitudinal sectional view showing a second embodiment, which differs from the first embodiment only in the engagement state of the internal spring 25.

A rod 30 that is movable within the chamber 24 is provided separately from the lever 26, and a spring receiver 30a is integrally extended in the radial direction of the rod 30, and one end of the rod 30 is brought into contact with the piston 18. , the other end is brought into contact with the lever 28.

An internal spring 25 is interposed between the spring receiver 30a and the spring receiver of the piston 18 and the plate 18a.

The variable load hydraulic pressure control valve configured in this manner also exhibits the same function as the first embodiment.

(Effects of the Invention) As explained in detail above, an internal spring is provided between the lever and the piston that can bias the piston in the valve opening direction until the input pressure when the vehicle is empty reaches the cut pressure for the maximum working pressure. As a result, even when no external input is applied, the brake force does not drop significantly or the rear wheels lock, ensuring optimal braking force.

Further, by constantly applying force to the external spring, the external spring is reliably held in the vehicle body under any conditions.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the first embodiment of the present invention when it is mounted on a vehicle body. FIG. 2 is a longitudinal cross-sectional view of the second embodiment of the present invention when it is mounted on a vehicle body. Fig. 4 is a vertical sectional view showing an example of a conventional variable load hydraulic pressure control valve; Fig. 4 is a front view showing how the conventional variable load hydraulic pressure control valve is mounted on the vehicle body; Fig. 5; FIG. 6 is a diagram showing the relationship between the input hydraulic pressure and the output hydraulic pressure of the variable load hydraulic pressure control valve. ! 1... Vehicle body 13φ... Link 14... External spring 15... Hydraulic pressure control valve body 18... Piston 25... Φ Internal spring 26 Fist... Lever Patent applicant Tokico Co., Ltd. No. 1 Figure 3

Claims (1)

[Claims] (1) The piston installed in the main body of the hydraulic control valve,
A rotatably pivoted lever is brought into contact with the lever,
An external spring is provided between the link, which has one end pivoted to the vehicle body and the other end fixed to the axle, and applies rotational force to the lever via the external spring in accordance with changes in vehicle height. In the variable load hydraulic pressure control valve, an internal spring is provided between the lever and the piston to bias the piston in the valve opening direction until the input pressure when the vehicle is empty reaches a cut pressure with respect to the maximum operating pressure. Intermediate,
A variable load hydraulic pressure control valve characterized in that the internal spring elastically biases the piston and the lever in opposite directions.