JPH0215735Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake hydraulic pressure control device used in a vehicle braking system, which reduces input hydraulic pressure at a constant rate to obtain output hydraulic pressure.

The brake fluid pressure control device applies the same braking force to the front and rear wheels when the braking force is low at the beginning of braking, and when the braking force exceeds a predetermined value, the braking force on the rear wheels is made smaller than that on the front wheels. This allows the front and rear wheels to lock at the same time. For this reason, the valve is opened and closed by a plunger that responds to the master cylinder pressure, and by opening and closing the valve, the master cylinder pressure is reduced to a predetermined rate and transmitted to the rear wheel side wheel cylinder.

By the way, a failure occurred in the hydraulic piping leading from the master cylinder to, for example, the front wheel side wheel cylinder.
If sufficient brake fluid pressure is no longer transmitted to the front wheel side wheel cylinder, and the plunger acts despite this, the brake fluid pressure as a whole will further decrease, reducing the safety of the vehicle.

For this reason, brake fluid pressure control devices have been proposed that have a fail-safe mechanism that directs fluid pressure from other systems directly to the foil cylinder when a failure occurs in one system of hydraulic piping, but all of them have a special fail-safe mechanism. However, the problem was that the structure was complicated and had a large number of parts.

In view of the above points, the present invention provides a brake hydraulic pressure control device having a fail-safe function with a simple configuration. Two systems of hydraulic pressure from the master cylinder are introduced into the front and rear surfaces to hold the sleeve in a stationary position with the front surface in contact with each other. A plunger that is received by the pressure receiving part, a spring that always biases the plunger in the front side direction, and a valve body provided in the front side introduction hydraulic pressure passage are provided, and the liquid is introduced from the front and rear surfaces from the master cylinder. The plunger is moved forward and backward against the spring by pressure to open and close the valve body, and a proportioning valve is configured to supply a reduced output hydraulic pressure to the foil cylinder according to the hydraulic pressure introduced on the front side, and the rear surface of the sleeve is configured. On the side, when the hydraulic pressure introduced to the rear side decreases abnormally, the sleeve is displaced toward the rear side and comes into contact with a plug fitted on the rear side and moves relative to the sleeve to bring the valve body to the open position. The plunger is characterized in that a protruding end portion of the plunger to be held is formed.

The present invention will be explained below with reference to illustrated embodiments. In the figure, a hole 3 is bored in a housing 2 connected to a master cylinder 1, and a plug 5 having a first output port 4 is screwed onto the opposite side of the hole 3 from the master cylinder 1. Further, a second output port 6 is formed on the master cylinder 1 side of the hole 3. The first output port 4 leads to the front wheel side wheel cylinder (not shown), and the hydraulic pressure from the master cylinder 1 led to the first input port 7 bored near the plug 5 of the hole 3 is connected to the front wheel cylinder (not shown). The signal is output from the first output port 4 as it is. That is, the hydraulic pressure generated by the master cylinder 1 is directly transmitted to the front wheel cylinder. On the other hand, the second output port 6 communicates with the rear wheel side wheel cylinder (not shown), and the input liquid from the master cylinder 1 is guided to the second input port 8 formed at the end of the hole 3. The pressure is controlled by a control valve mechanism, which will be described later, and is reduced and transmitted at a constant rate.
In other words, when the input hydraulic pressure from the master cylinder 1 exceeds a predetermined value, a hydraulic pressure lower than the input hydraulic pressure is transmitted to the rear wheel side wheel cylinder.

The sleeve 9 slidably fitted into the hole 3 has a substantially cylindrical shape, and has an annular joint 10 projecting inward to form a valve chamber 11 on the master cylinder 1 side. A central portion of the joint portion 10 is a valve hole 12, and a ball valve 13 for opening and closing the valve hole 12 is housed in the valve chamber 11. The ball valve 13 is always urged to close the valve hole 12 by a spring 15 elastically loaded between an annular spring seat 14 fitted to the end of the valve chamber 11. During operation, the rod 19a of the plunger 19, which will be described later,
is pressed to open the valve hole 12. In addition,
An annular sheet member 1 is provided on the inner wall of the joint portion 10 on the valve chamber 11 side.
6 is attached to ensure that the valve hole 12 is completely blocked by the ball valve 13.

A sliding chamber 18 is provided on the opposite side of the joint portion 10 from the valve chamber 11.
A plunger 19 is slidably supported within this chamber 18. A rod 19a that can penetrate the valve hole 12 and come into contact with the ball valve 13 is provided on the end face of the plunger 19, and a groove 1
9b is carved, so that the hydraulic pressure introduced from the master cylinder 1 into the valve chamber 11 via the second input port 8 during non-operation is directly transmitted to the second output port 6. That is, a through hole 22 is bored in the vicinity of the joint 10 of the sleeve 9, and when the sleeve 9 is not in operation, pressure oil flows through the valve chamber 11 and the valve hole 1.
2. The liquid flows to the second output port 6 through the groove 19b and the through hole 22. Note that the hole 3 of the second output port 6
The side opening is recessed long in the axial direction of the sleeve 9, so that even if the sleeve 9 moves, the through hole 22 is always kept in the second position.
It is made to communicate with the output port 6.

Now, most of the sleeve 9 has the same diameter as the hole 3, but the diameter on the plug 5 side is slightly smaller, forming a reduced diameter part 9a, and between the end of this reduced diameter part 9a and the plug 5. A spring 17 is provided to bias the sleeve 9 toward the master cylinder 1. Therefore, under normal conditions when the same pressure is applied to the first and second input ports 7 and 8, the sleeve 9 is in contact with the inner wall of the hole 3 on the master cylinder 1 side and is stationary; In the event of an abnormality in which sufficient hydraulic pressure is not introduced to the sleeve 9, the sleeve 9 receives pressure from the second input port 8 and moves toward the plug 5 while bending the spring 17. Note that the axial length of the reduced diameter portion 9a is the first length when the sleeve 9 moves toward the plug 5 side.
The length is set so as not to block the input port 7.

The inner diameter of the shaft hole 9b of the reduced diameter portion 9a is the sliding chamber 1.
The small diameter portion 19c of the plunger 19 is slidably inserted into the shaft hole 9b. This plunger small diameter part 19
A snap spring 20 is fitted into the protruding portion from the shaft hole 9b of c, and a spring 21 is provided between the snap spring 20 and the plug 5, thereby biasing the plunger 19 toward the master cylinder 1 side, and thereby During operation, the rod 19a is brought into contact with the joint 10 and presses the ball valve 13 to open the valve hole 12. However, the tip of the small diameter portion 19c extends toward the plug 5 and faces the bottom surface thereof, and as will be described later, the sleeve 9 and the plunger 19 are When moved toward the plug 5 side, the tip of the small diameter portion 19c comes into contact with the plug 55, thereby maintaining the open state of the ball valve 13.

To explain the normal operation of this embodiment device, when the hydraulic pressure generated by the master cylinder 1 is relatively low, the hydraulic pressure introduced into the first input port 7 passes through the hole 3 and the first output port 4. The hydraulic pressure is then transmitted to the front wheel side wheel cylinder and introduced into the second input port 8 through the valve chamber 11, the valve hole 12, the groove 19b,
It is transmitted to the rear wheel side wheel cylinder through the through hole 22 and the second output port 6. However, when the hydraulic pressure generated in the master cylinder 1 exceeds a predetermined value, the first
The hydraulic pressure output from the output port 4 is the same as the generated hydraulic pressure as described above, but the hydraulic pressure output from the second output port 6 is lower than the generated hydraulic pressure of the master cylinder 1 as follows. The pressure is reduced.

That is, in the plunger 19, the hydraulic pressure from the first input port 7 acts on one end, and the hydraulic pressure from the second input port 8 acts on the other end, and these hydraulic pressures are the same pressure, but the plunger 19 Since the pressure-receiving area of both end faces is larger on the second input port 8 side, the plunger 19 moves to the right, and together with this, the ball valve 13 seats on the seat member 16 and closes the valve hole 12. The increase in output hydraulic pressure from the second output port 6 is stopped. Furthermore, master cylinder 1
When the generated hydraulic pressure increases, the hydraulic pressure acting on the right end surface of the plunger 19 increases, but the hydraulic pressure acting on the left end surface does not increase due to the blockage of the valve hole 12, so the plunger 9 moves to the left and closes the ball valve. 13 to open the valve hole 12. However, plunger 1 again
The hydraulic pressure acting on the left end face of the second output port 6 increases, and the same operation is repeated to reduce the output hydraulic pressure from the second output port 6 at a constant rate.

On the other hand, the hydraulic pressure introduced into the first input port 7 is
When the hydraulic pressure is abnormally lower than the hydraulic pressure introduced to the second input port 8, the sleeve 9 moves to the right while bending the spring 17 due to the difference in these hydraulic pressures, and the plunger 19 also moves to the right and the small diameter portion 19c end of the sleeve 9 moves to the right. is plug 5
comes into contact with. As a result, the sleeve 9 interferes with the snap spring 20 and stops, and in this state,
The rod 19a presses the ball valve 13 to open the valve hole 12.
maintain the open state. Therefore, the hydraulic pressure introduced to the second input port 8 is always outputted as is to the second output port 6, and the hydraulic pressure generated in the master cylinder 1 is not reduced as in the normal state.

As described above, the sleeve 9 is stationary under normal conditions, and only the operation of the plunger 19 and the valve body 13 performs the pressure reducing action. Therefore, the flow amount of pressure oil in the hole 3 can be kept to the necessary minimum, and the operation of supplying pressure oil to the foil cylinder is stable and reliable.

Further, in maintenance and inspection of the valve mechanism in this device, the entire valve mechanism can be taken out by simply removing the plug 5 and pulling out the sleeve 9, making the work easy.

As described above, according to the present invention, it is possible to obtain a brake hydraulic pressure control device having a fail-safe function with a small number of parts and a simple configuration.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. 1...Master cylinder, 2...Housing,
3...hole, 9...sleeve, 12...valve hole, 13
... Ball valve, 19 ... Plunger.

Claims (1)

[Scope of utility model registration request] A substantially cylindrical sleeve is slidably fitted into the hole of the housing, and two systems of hydraulic pressure from a master cylinder are introduced to the front and rear surfaces of this sleeve to bring the sleeve into a resting position with the front surfaces in contact with each other. In addition, within the sleeve, there is a plunger that receives the liquid pressure introduced from the front and rear surfaces with pressure receiving parts having different pressure receiving areas, a spring that always biases this plunger in the front side direction, and a plunger that receives the liquid pressure introduced from the front and rear surfaces. A valve body provided in a pressure passage is provided, and the plunger is moved forward and backward against the spring by the hydraulic pressure introduced from the front and rear surfaces from the master cylinder to open and close the valve body in response to the hydraulic pressure introduced from the front side. A proportioning valve is configured to supply reduced output hydraulic pressure to the foil cylinder, and a proportioning valve is provided on the rear side of the sleeve to prevent the sleeve from displacing toward the rear side when the hydraulic pressure introduced to the rear side decreases abnormally. A braking hydraulic pressure control device characterized in that a protruding end portion of the plunger is formed, the protruding end portion of the plunger coming into contact with a plug fitted on the rear surface side and moving relative to the plug to hold the valve body in an open position.