JPH071331Y2 - Brake fluid pressure control device - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention relates to the increase rate of the hydraulic pressure of the rear wheel cylinder used in the hydraulic brake system for a vehicle to the increase of the hydraulic pressure of the master cylinder. Regarding the brake fluid pressure control device for controlling the lock of the rear wheel by controlling it smaller than the ratio,
In particular, the present invention relates to a brake fluid pressure control device having a mechanism for disabling the above control when the fluid pressure circuit from the master cylinder to the front wheel cylinder is broken.

(Prior Art) A conventional device of this type is disclosed in Japanese Utility Model Laid-Open No. 59-47564. This valve opens when the hydraulic pressure difference before and after the proportioning valve reaches a specified value in a bypass circuit that is installed in parallel with the proportioning valve that controls the hydraulic pressure of the rear wheel cylinder compared to the hydraulic pressure of the master cylinder. A check valve that connects the master cylinder and the rear wheel cylinder to each other without using a proportioning valve is provided, and the check valve is used to receive the hydraulic pressure of the rear wheel cylinder at one end and the hydraulic pressure of the front wheel cylinder at the other end. When the hydraulic pressure of the rear wheel cylinder is higher than the hydraulic pressure of the front wheel cylinder, the balance piston slides in the valve opening direction by a predetermined amount when the hydraulic pressure of the rear wheel cylinder becomes higher than that of the front wheel cylinder. Only the movement from the fixed position of the piston to the moving position is connected by the connecting means that transmits to the check valve. It is.
Thus, when the hydraulic circuit on the front wheel cylinder side fails, the hydraulic pressure of the rear wheel cylinder is made equal to the hydraulic pressure of the master cylinder regardless of the operation of the proportioning valve to prevent the braking force from becoming insufficient. In addition, the actual development Sho 57-12346
In the publication, in the hydraulic control device for the rear two-system hydraulic pipe, the separation of the control piston that constitutes the proportioning valve of one system is limited to a certain length or less by a fail-safe clip, and when both are normal, both pistons are controlled. Allow each slide, and when one of the systems fails, the control piston slide is regulated by a fail-safe clip.
Braking force is secured by restricting the operation of the proportioning valve.

(Problems to be Solved by the Invention) However, in the former device of the related art described above, since the connecting means is formed integrally with the balance piston, the machining cost of the balance piston increases, and the brake fluid pressure control device concerned. However, there is a problem that the manufacturing cost increases and becomes expensive. Further, in the latter device, a fail-safe clip is provided so that the opposite left and right opposite side edges of both lateral U-shaped legs form a circular inner surface intermittently formed by the opposite arcuate portions, and one opposite arcuate portion is controlled. The piston is fitted and fixed in the circumferential groove of the piston, and the other opposing arcuate portion is loosely fitted in the circumferential groove of the balance piston with a degree of freedom in the axial direction. As a result, backlash in the axial direction occurs at one of the opposing arcuate portions, and the backlash cannot control the reciprocating sliding of the control piston, which causes the proportioning valve to operate, possibly resulting in insufficient braking force. Atsuta

In view of this, the present invention is to make it possible to reliably regulate the operation of the proportioning valve in the event of a failure of the hydraulic circuit on the front wheel cylinder side without increasing the manufacturing cost in the brake fluid pressure control device. This is a technical issue.

[Constitution of device]

(Means for Solving the Problem) The technical means taken to solve the above-described technical problem is a brake fluid pressure control device in which the diameter of the stepped piston is increased to the bypass piston side end portion. The bypass piston is fitted and inserted with a window portion for providing a coupling portion, the coupling means having a cylindrical shape with a bottom, and the engagement portion being accommodated in the hole so as to be movable by a predetermined amount so as to be engageable with the bottom portion. And a needle pin that fixes the sleeve and the bypass piston.

(Operation) According to this, it is possible to reliably prevent axial play of the sleeve with respect to the bypass piston, and it is possible to reliably restrict the movement of the stepped piston toward the valve closing side of the valve mechanism. Secure the braking force when the front brake hydraulic line fails.

Embodiment An embodiment of the brake fluid pressure control device according to the present invention will be described below with reference to the drawings.

In FIG. 1, the brake fluid pressure control device 10 includes a front brake fluid pressure line P1 and a rear brake fluid pressure line P2 extending from the master cylinder 40 to the front wheel cylinder 50 and the rear wheel cylinder 60 in the vicinity of the master cylinder 40.
And a proportioning valve V having a stepped piston 12, an elastic seal valve 13, and a spring 14 in a body 11 and interposed in a rear brake hydraulic pressure line P2,
A bypass piston (20), which is arranged so as to face the stepped piston (12) and has one end exposed in the front brake conduit (P1) and the other end exposed in the rear brake conduit (P2), and the bypass piston (20).
And connecting means 22 for connecting the stepped piston 12 and the stepped piston 12.

The body 11 has a stepped inner hole 11a with one end opened inside, and the body 11 is opened to the stepped inner hole 11a.
Rear brake hydraulic line P2 and front brake line P at 0
Inlet ports 11b and 11c, which are communicated via 1 respectively
And an outlet port 11d opened to the stepped inner hole 11a and connected to the rear wheel cylinder 60, and an outlet port 11e opened to the stepped inner hole 11a and connected to the front wheel cylinder 50. There is.

A cylindrical member 1 that is slidable in a liquid-tight manner in the stepped inner hole 11a and is locked to the stepped portion of the stepped inner hole 11a via a spacer 19.
5 is fitted and a plug 16 for closing the opening is liquid-tightly fitted in the opening, and the plug 16 is formed by a ring fitted near the opening of the stepped inner hole 11a. Inner hole 1
The escape from 1a is prevented.

The stepped piston 12 is supported in the inner hole of the tubular member 15 and the inner hole of the plug 16 so as to be slidable in the axial direction, and a spring 14 having one end locked by a retainer 17 locked by the plug 16. The other end is locked to the flange portion 12a and is biased to the right in the figure. Further, on the upper part of the stepped piston 12, there is formed a valve portion 12b which constitutes a valve mechanism by an annular elastic seal valve 13 fixedly provided on an inner peripheral step portion of the tubular member 15a. The valve mechanism controls the communication between the inlet port 11b and the outlet port 11d on and off, and when the stepped piston 12 slides to the right in the figure, the valve portion 12b
Is separated from the elastic seal valve 13, and allows the master cylinder 40 and the rear wheel cylinder 60 to communicate with each other through the stepped inner hole 11a and acts on the stepped piston 12. The force to the left in the figure due to the difference between the pressure receiving area of the master cylinder hydraulic pressure from the master cylinder 40 and the pressure receiving area of the rear wheel cylinder hydraulic pressure of the rear wheel cylinder 60, and the force to the right side in the figure due to the biasing force of the spring 14. When sliding to the left in the figure due to the balance with the valve part 12b, the elastic seal valve 1
Seated in 3 and master cylinder 40 and rear wheel cylinder 6
The communication with 0 is cut off, and the rising gradient of the rear wheel cylinder hydraulic pressure is reduced to a predetermined value with respect to that of the master cylinder hydraulic pressure. The tubular member 15 is urged rightward in the drawing together with the spring 4 by a spring 18 whose one end is locked by a retainer 17.

Further, the bypass piston 20 is fluid-tightly fitted in the stepped inner hole 11a so as to be slidable by a predetermined amount on the bottom side thereof. The bypass piston 20 is biased toward the stepped piston 12 side by a spring 21 that is locked at the bottom of the stepped inner hole 11a at one end, and one end is exposed in the front brake conduit P1 and the other end is rear. It is exposed in the brake pipe P2 and is slidable due to the pressure difference, and when it slides to the right in the drawing by the connecting means 22 to be described later, it is combined with the stepped piston 12 to form the stepped piston 12. Is prevented from sliding to the left in the figure.

The connecting means 22 has a bottomed tubular shape as shown in FIGS. 2 and 3, and allows the enlarged engagement portion 12c formed at the right end of the stepped piston 12 in the figure to move into the hole 23a. Housing and engaging part
A sleeve 23 having a window 23c that allows the side surface of 12c to be engaged with the bottom portion 23b thereof and a tubular shape 23d into which the bypass piston 20 is fitted, and an axial center of the tubular portion 23d of the sleeve 23 that is orthogonal to each other. The sleeve 23 and the bypass piston are inserted into the formed hole 23d and the hole 20a formed at the other end of the bypass piston 20 so that the axis of the bypass piston 20 is orthogonal to each other in the piston axial direction without play.
It is composed of a needle pin 24 for fixing 20 and 20.
As a result, the bypass piston 20 is normally held by the spring 21 in the illustrated fixed position where the sleeve 23 is in contact with the spacer 19, and the hydraulic pressure in the rear brake hydraulic pressure line P2 is higher than that in the front brake hydraulic pressure line P1. When the pressure becomes high, the valve mechanism slides in the valve opening direction by a predetermined amount, and the connecting means 22 moves from the fixed position to the moving position (moving to the right in the figure).
Is transmitted to the stepped piston 12 to restrict sliding of the stepped piston 12 toward the valve closing direction of the valve mechanism.

The operation of this embodiment having the above configuration will be described.

The brake fluid pressure control device 10 includes a front brake fluid pressure line.
When P1 is normal, the bypass piston 20 is held in the first illustrated fixed position, the stepped piston 12 repeats reciprocal sliding, and the proportioning valve V performs known pressure reduction control.

When the front brake hydraulic pipe P1 fails, the bypass piston 20 slides to the right in the drawing due to the pressure difference acting on both ends, and the bottom portion 23b of the sleeve 23 engages with the engaging portion 12c of the stepped piston 12 to move the step. A valve mechanism is maintained in an open state by restricting sliding of the attached piston 12 toward the valve closing direction of the valve mechanism. This prevents the braking force from being insufficient due to the operation of the pillow position valve V to reduce the hydraulic pressure of the rear wheel cylinder 60 in the state where the control force of the front wheel cylinder 50 is insufficient.

Thus, in this embodiment, the sleeve 23 and the bypass piston 20 are connected by the needle pin 24. Therefore, the axial play of the sleeve 23 with respect to the bypass piston 20 can be reliably prevented, the movement of the stepped piston 12 toward the valve closing side of the valve mechanism can be reliably controlled, and the front brake fluid can be prevented. The braking force when the pressure line P1 fails can be secured. Further, after the bypass piston 20 and the sleeve 23 are coupled by the needle pin 24 so as not to move relative to each other, the stepped piston 12 can be assembled from the window portion 23c, so that not only the assembly and disassembly workability are good, Since the needle pin 24 bears a tensile load by moving the bypass piston 20 to the right in the drawing and moving the stepped piston 12 to the left in the drawing, the brake fluid pressure control device can be made compact.

[Effect of device]

As described above, according to the present invention, the needle pin can reliably make the sleeve and the bypass piston immovable relative to each other, so that the operation of proportioning at the time of the failure of the front brake hydraulic pressure line is surely performed. It is possible to regulate, lock the rear wheel normally and secure the braking force in case of failure of the front brake hydraulic pressure line, and at the same time, the needle pin is used in the place that can withstand pulling. As a result, the brake fluid pressure control device can be downsized.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a brake fluid pressure control device according to the present invention, and FIG. 2 is a plan view of the sleeve shown in FIG.
FIG. 3 is a side view of the sleeve shown in FIG. 10 …… Brake fluid pressure controller, 11 …… Body, 11a ……
Stepped bore, 12 …… Stepped piston, 12b …… Valve part, 12c
...... Engagement part, 13 ...... Elastic seal valve, 14 ...... Spring, 16 ...... Plug, 20 ...... Bypass piston, 22 ...... Coupling means, 23 ...... Sleeve, 23 a ...... hole, 23 b ...... Bottom part, twenty three
c …… window, 23d …… cylindrical part, 24 …… needle pin, 40 ……
Master cylinder, 50 ... Front wheel cylinder, 60
…… Rear wheel cylinder, P1 …… Front brake hydraulic line, P2 …… Rear brake hydraulic line, V …… Proportioning valve.

Claims (1)

[Scope of utility model registration request] 1. A hydraulic pressure of the master cylinder and the rear wheel cylinder, which are slidably fitted in an inner hole of a body interposed in a rear brake hydraulic pressure line extending from the master cylinder to the rear wheel cylinder. From the stepped piston having a valve mechanism that slides back and forth due to the difference in the hydraulic pressure receiving area to intermittently control the communication of the hydraulic circuit, and a spring that normally urges the valve mechanism of the stepped piston in the valve opening direction. And a hydraulic pressure in the rear wheel cylinder and a hydraulic pressure in the front brake hydraulic pressure line, which are slidably fitted in the inner hole so as to be slidable in a liquid-tight manner so as to face the stepped piston. Is held in a normal position during normal operation, and when the hydraulic pressure in the rear brake hydraulic pressure line becomes higher than the hydraulic pressure in the front brake hydraulic pressure line, a predetermined amount is slid in the valve opening direction of the valve mechanism. A moving bar The bypass piston and the bypass piston capable of restricting the sliding of the stepped piston toward the valve closing direction of the valve mechanism by transmitting only the movement of the bypass piston from the fixed position to the moving position to the stepped piston. And a connecting means for connecting the stepped piston, in a brake fluid pressure control device, wherein an engaging portion having an enlarged diameter is provided at an end of the stepped piston on the bypass piston side, and the connecting means has a bottomed cylinder. And a sleeve having a window portion that accommodates the engagement portion movably in the hole and engages with the bottom portion of the engagement portion, and a tubular portion into which the bypass piston is fitted, and the sleeve and the sleeve. A brake fluid pressure control device comprising a needle pin for fixing a bypass piston.