JPH0143967Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vehicle deceleration sensing type brake fluid pressure control device that controls rear wheel brake fluid pressure of a vehicle, and in particular, to a vehicle deceleration sensing type brake fluid pressure control device that has both the so-called S valve function and P valve function. The present invention relates to a sensing type brake fluid pressure control device.

Conventionally, as this type of device,
There is one disclosed in Japanese Patent Publication No. 2003-100002 and shown in FIG. 3. This device includes a body 1, a stepped control piston 2, and a spring 3 that biases the piston to the right.
Seal ring 4 attached to the right end of control piston 2
The main components are a ball 5 that can be seated on the ball 5, and a needle 6 that extends axially through a passage 2a provided in the control piston 2 and is fixed to the body 1 at its left end. This device is compact because the control piston 2, spring 3, seal ring 4, ball 5, and needle 6 are coaxially assembled in the inner hole 1a of the body 1.
In addition, in this device, during braking, after the ball 5 is seated on the seal ring 4 and a so-called G valve function is obtained, the control piston 2 and the ball 5 move to the left as a unit, and the ball 5 engages with the needle 6. By separating them from the seal ring 4, a so-called P-valve function is obtained. By the way, since the above-mentioned P valve function is obtained by the ball 5, seal ring 4, control piston 2, and needle 6, which are susceptible to vibration (vehicle body vibration), the control characteristics of the device cannot be stably obtained. There is a risk. Further, in this device, the ball 5 senses a predetermined deceleration and seats on the seal ring 4. For this reason, as shown in Figure 2, there is an ideal distribution line for front and rear brake fluid pressure (hereinafter simply referred to as the ideal distribution line) when the load is light and the ideal distribution when the load is large and constant. In a vehicle where the lines are far apart, if the timing of seating the ball 5 on the seal ring 4 is set so as to obtain control characteristics that approximate the ideal distribution line when the load is light, the control characteristics when the load is constant becomes too low than the ideal distribution line, resulting in insufficient braking force. On the contrary, if the timing of the seating of the ball 5 on the seal ring 4 is set so as to obtain a control characteristic that approximates the ideal distribution line at constant load, the control characteristic at light load will be the ideal distribution line. If it gets too high above the line, it will cause the rear wheels to lock up.

This invention was created in view of the actual situation,
The purpose of this is to create a compact vehicle that can obtain control characteristics that approximate the ideal distribution lines for both ideal distribution lines, respectively, in vehicles where the ideal distribution lines for light loads and constant loads are far apart, and that can stably obtain the control characteristics. An object of the present invention is to provide a deceleration sensing type brake fluid pressure control device for a vehicle.

The deceleration-sensing brake fluid pressure control device for a vehicle according to the present invention has an inflow port connected to a brake master cylinder and an outflow port connected to a rear wheel cylinder, and has an internal port that communicates with both ports. a body provided with a hole; a first liquid chamber provided in an intermediate interior of the body that communicates the inner hole with the inflow port; and a second liquid chamber that communicates with the outflow port.
a partition wall having a communication hole that partitions into a liquid chamber and communicates both the liquid chambers; and a stepped inner hole that is provided in parallel with the communication hole and has a larger diameter on the second liquid chamber side; A first tube provided in the body at a neck portion provided within the liquid chamber and having a larger diameter than the large diameter inner hole of the stepped inner hole.
The seal ring constitutes a hydraulic pressure control valve, and the stepped leg portion is fitted into the stepped inner hole liquid-tightly and slidably in the axial direction to form an air chamber, and the stepped leg portion is fitted into the stepped inner hole to form an air chamber, and the stepped leg portion is fitted into the stepped inner hole so as to be slidable in the axial direction. a stepped piston having a communication hole that communicates the inside of the stepped inner hole with the port; a spring that urges the stepped piston toward the outflow port; an inertial response valve body that seats on a second seal ring provided at the opening end of the stepped inner hole on the first liquid chamber side and blocks communication between the first liquid chamber and the stepped inner hole when speed is sensed; the first liquid chamber side end of the stepped piston protrudes into the first liquid chamber through the second seal ring when the stepped piston moves a predetermined amount against the spring; A stopper is provided to prevent the valve body from seating on the second seal ring.

In a device with such a configuration, by appropriately setting the timing at which the inertial response valve element seats on the second seal ring, etc., the P valve function can be obtained after the G valve function is obtained during a light load. This makes it possible to obtain control characteristics that are close to the ideal distribution line at light loads, and at the same time, before the inertia-responsive valve element seats on the second seal ring at constant load, the inertia-responsive valve element is moved to the second seal ring at the stopper. It is possible to prevent the G valve function and the P valve function from being obtained by preventing the valve from seating on the seal ring, and it is possible to obtain control characteristics that approximate the ideal distribution line at constant volume. In addition, the first seal ring, stepped piston, second seal ring, and inertial response valve body are coaxially assembled in the inner hole of the body, making it compact. The G-valve function is achieved by the inertia-responsive valve body, and the P-valve function is achieved by the first seal ring provided on the body and the stepped piston, which is almost unaffected by vibration.
G-valve function and P-valve function can each be stably obtained.

An embodiment of the present invention will be described below based on the drawings. In the vehicle deceleration sensing type brake fluid pressure control device shown in FIG. The second body 14 has an outflow port 10b, and both ports 10a,
An inner hole 10c is formed to communicate with the inner hole 10b. The inflow port 10a is connected to one pressure chamber of the tandem brake master cylinder MC through a pipe P1, and the outflow port 10b is connected to the rear wheel cylinder RC through a pipe P2. Note that the front wheel cylinder FC is connected to the other pressure chamber of the tandem brake master cylinder MC by a pipe P3.

Furthermore, inside the body 10, a partition member 20 and a ball case 30 are assembled, as well as a stepped piston 40 and a ball (inertial response valve body) 50. The partition member 20 is provided in the middle part of the inner hole 10c of the body 10, and
a first liquid chamber R1 that communicates the inside of c with the inflow port 10a;
and a second liquid chamber R2 communicating with the outflow port 10b. The partition member 20 is positioned together with the ball case 30 by a pin 21 and a spring 60, and has a stepped inner hole 20a in the center with a larger diameter on the second liquid chamber R2 side, and has a stepped inner hole 20a with a larger diameter on the second liquid chamber R2 side. It has a communication hole 20b that allows the chambers R1 and R2 to communicate with each other.

The stepped piston 40 constitutes a hydraulic control valve (P valve) with a first seal ring 41 provided on the second body 14 at a neck portion 40a having a larger diameter than the large diameter inner hole of the stepped inner hole 20a. Then, the stepped leg portion 40b
to the partition wall member 2 via a pair of O-rings 42 and 43.
It is assembled by fitting slidably in the axial direction into the stepped inner hole 20a of No. 0, and is biased leftward by a spring 44 interposed between the partition members 20. Air chamber A1 in the large diameter step part of 20a
is formed. Further, the stepped piston 40 has a communication hole 40c in its axis that communicates the outflow port 10b with the inside of the stepped inner hole 20a, and has a rod-shaped stopper 40d at its right end. on the other hand,
The ball 50 constitutes a shutoff valve (G valve) with a second seal ring 51 provided at the opening end of the partition member 20 on the first liquid chamber R1 side, and is rotatably housed in the ball case 30. ing. Therefore, when the stepped piston 40 moves a predetermined amount against the spring 44 and comes into contact with the small diameter stepped portion of the stepped inner hole 20a in the partition member 20, the rod-shaped stopper 40d passes through the second seal ring 51 and the first Liquid chamber R
The ball 5 is formed to have a length that protrudes into the second seal ring 51, and the ball 5 is formed in a length that protrudes into the second seal ring 51.
0 from seating on the second seal ring 51.

The device configured as described above is used by being attached to a vehicle body such as a truck with a predetermined inclination angle θ, and when braking, as shown in Fig. 2, the device is applied to the rear wheel cylinder RC. Controls hydraulic pressure according to the vehicle's loading status. The action will be explained in detail below.

When the driver depresses the brake pedal to stop the vehicle, the tandem brake master cylinder
MC is activated, hydraulic pressure is applied from the other pressure chamber of the tandem brake master cylinder to the front wheel cylinder FC via pipe P3, and hydraulic pressure (master cylinder hydraulic pressure) is applied from one pressure chamber of the tandem brake master cylinder. It is applied to the rear wheel cylinder RC via the pipe P1, the brake fluid pressure control device, and the pipe P2, and both the front and rear brakes start operating, and the braking action begins. During this time, the hydraulic pressure within the brake hydraulic pressure control device is transmitted through the inflow port 10.
a, first liquid chamber R1, second seal ring 51, stepped inner hole 20a, communicating hole 40c of stepped piston 40,
Outflow port 10b and inflow port 10a,
The cleaning is performed in the order of the first liquid chamber R1, the communication hole 20b, the second liquid chamber R2, the first seal ring 41, and the outflow port 10b.

Therefore, when the load is light, when the master cylinder hydraulic pressure PM reaches Pm1 in FIG. 2, the vehicle deceleration reaches a predetermined value, the ball 50 seats on the second seal ring 51, and the inflow port 10a Communication hole 40c of stepped piston 40 from to outflow port 10b
Hydraulic pressure transmission through is interrupted. By the way, at this time, the neck 40a of the stepped piston 40 is in the first position.
The second liquid chamber R2 is located away from the seal ring 41.
Since the outflow port 10b and the outflow port 10b are in communication through the first seal ring 41, hydraulic pressure continues to be transmitted from the inflow port 10a to the outflow port 10b.
Thus, when the point A in FIG. 2 is reached, the neck 40a of the stepped piston 40 contacts the first seal ring 41, cutting off communication between the second liquid chamber R2 and the outflow port 10b, and thereafter the master cylinder liquid pressure PM As the hydraulic pressure increases, the stepped piston 40 and the first seal ring 4
1 operates a conventionally known P valve, and the hydraulic pressure applied to the rear wheel cylinder RC (rear wheel cylinder hydraulic pressure PW) is controlled to be reduced. In addition, when the master cylinder hydraulic pressure PM is more than Pm1, ball 5
0 continues to be seated on the second seal ring 51. As described above, when the vehicle is lightly loaded, the rear wheel cylinder hydraulic pressure PW is controlled as shown by the line connecting points 0, A, and B in FIG.

Also, during half-loading (between light loading and constant loading), the master cylinder hydraulic pressure PM is Pm2 (point C).
When the deceleration of the vehicle reaches a predetermined value, the ball 50 seats on the second seal ring 51, and hydraulic pressure is transmitted from the inflow port 10a to the outflow port 10b through the communication hole 40c of the stepped piston 40. is blocked. However, at this time, the previous A
At the point, the neck 40a of the stepped piston 40 is the first
Since communication between the second liquid chamber R2 and the outflow port 10b is blocked by contacting the seal ring 41, hydraulic pressure transmission from the inflow port 10a to the outflow port 10b is completely blocked. Note that between point A and point C, the stepped piston 40 is pushed to the right and fits into the first seal ring 41, but it does not come into contact with the small diameter step of the stepped inner hole 20a. First, the rod-shaped stopper 40d does not protrude from the second seal ring 51. In such a state, the master cylinder hydraulic pressure PM is Pm4.
continues until it reaches. Master cylinder hydraulic pressure PM
When Pm4 is reached, the stepped piston 40 receives the increase in master cylinder hydraulic pressure PM at the neck 40a, moves to the left, and finally reaches the neck 40a of the stepped piston 40.
is removed from the first seal ring 41, and thereafter, as the master cylinder hydraulic pressure PM increases, the stepped piston 40 and the first seal ring 41 perform the conventionally known P valve operation, and the rear wheel cylinder hydraulic pressure PW increases. Depressurization controlled. In addition, master cylinder hydraulic pressure PM
When Pm2 or more, the ball 50 continues to be seated on the second seal ring 51. As mentioned above, at half load, the rear wheel cylinder hydraulic pressure PW is the second
It is controlled as shown by the line connecting points 0, C, D, and B in the figure.

Furthermore, at constant volume, the master cylinder hydraulic pressure
When PM reaches Pm3 (point E), the vehicle deceleration reaches a predetermined value and the ball 50 moves to the second seal ring 5.
Trying to sit on number 1. At this time, the neck 40a of the stepped piston 40 contacts the first seal ring 41 at the previous point A, and the neck 40a of the stepped piston 40 contacts the first seal ring 41 and the second
Cut off the communication between the liquid chamber R2 and the outflow port 10b,
Between point A and point E, the stepped piston 40 is pushed to the right, fits into the first seal ring 41, and comes into contact with the small-diameter stepped portion of the stepped inner hole 20a, and the rod-shaped stopper 40d From the seal ring 51 to the first liquid chamber R
Protrude within 1. Therefore, ball 50 is the second
The master cylinder hydraulic pressure PM in the first liquid chamber R1 is not seated on the seal ring 51, and the master cylinder hydraulic pressure PM in the first liquid chamber R1 is not seated on the second seal ring 5.
1. It continues to be applied to the rear wheel cylinder RC through the stepped inner hole 20a, the communication hole 40c of the stepped piston 40, and the outflow port 10b. As mentioned above,
At constant volume, rear wheel cylinder hydraulic pressure
PW becomes as shown by the line connecting points 0 and F in Figure 2.

Therefore, according to the device shown in Fig. 1, the rear wheel cylinder hydraulic pressure PW is equal to the ideal distribution line at light loading, the ideal distribution line at half loading, and the ideal distribution line at half loading shown by the dashed line in Fig. It is controlled to approximate the ideal distribution line at the time of accumulation.

By the way, in the device shown in FIG.
1, stepped piston 40, second seal ring 51,
Since the balls 50 are coaxially assembled, it is compact, and the second seal ring 51 provided on the immovable partition member 20 and the balls 50,
A function (G valve function) is provided to cut off the transmission of hydraulic pressure when the vehicle deceleration exceeds a predetermined value,
In addition, the first seal ring 41 provided on the body 10 and the stepped piston 40 are hardly affected by vibration.
Since the function to reduce the fluid pressure (P valve function) can be obtained by using the
The characteristics shown in the figure can be stably obtained.

[Brief explanation of the drawing]

Fig. 1 is a brake system diagram including the vehicle deceleration sensing type brake fluid pressure control device according to the present invention, Fig. 2 is a characteristic diagram obtained by the device shown in Fig. 1, and Fig. 3 is a diagram of a conventional example. FIG. Explanation of symbols, 10... Body, 10a... Inflow port, 10b... Outflow port, 10c... Inner hole, 20... Partition member, 20a... Stepped inner hole, 2
0b...Communication hole, 40...Stepped piston, 40a
...Neck, 40b...Stepped leg, 40c...Communication hole, 40d...Bar-shaped stopper, 41...First seal ring, 44...Spring, 50...Ball (inertial response valve body), 51... ...Second seal ring,
MC……Tandem brake master cylinder, RC
... Rear wheel cylinder, R1 ... First liquid chamber,
R2...Second liquid chamber, A1...Air chamber.

Claims (1)

[Scope of utility model registration request] A body having an inflow port connected to a brake master cylinder and an outflow port connected to a rear wheel cylinder, and an inner hole communicating between the two ports, and a body provided in the middle of the body. The inner hole is divided into a first liquid chamber that communicates with the inflow port and a second liquid chamber that communicates with the outflow port, and a communication hole that communicates both liquid chambers and a second liquid chamber that is provided in parallel therewith. a partition wall having a stepped inner hole with a larger diameter on the liquid chamber side;
A liquid pressure control valve is constituted by a first seal ring provided in the body at a neck portion of the stepped inner hole having a larger diameter than the large diameter inner hole of the stepped inner hole. A stepped inner hole that fits liquid-tightly and slidably in the axial direction to form an air chamber, and has a communication hole in the axial center that communicates the outflow port with the inside of the stepped inner hole. a piston, a spring that biases the stepped piston toward the outflow port, and an opening end of the stepped inner hole on the first liquid chamber side provided in the first liquid chamber when a predetermined deceleration is detected. an inertial response valve element that is seated on a second seal ring provided in the stepped piston to block communication between the first liquid chamber and the stepped inner hole; a stopper that protrudes into the first liquid chamber through the second seal ring and prevents the inertia-responsive valve body from seating on the second seal ring when the attached piston moves a predetermined amount against the spring. Deceleration sensing type brake fluid pressure control device for vehicles.