JPS6210861B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deceleration sensing type hydraulic pressure control device using a vehicle brake hydraulic system.

In general, it is considered desirable for vehicle safety braking to control the front and rear wheel braking force of a vehicle to be greater for the front wheels and smaller for the rear wheels due to the force of pressing the wheels against the road surface during braking. In other words, although it depends on the loading condition of the vehicle, it is normal for the rear wheels to apply less force to the road surface than the front wheels, so applying equal braking force to the front and rear wheels will lock the rear wheels. This is because there is a risk of inviting the phenomenon of

In view of these characteristics of the brake system, proportioning is developed to suppress an excessive increase in rear wheel brake force by controlling the front wheel brake fluid pressure from a predetermined value to the rear wheel brake fluid pressure. Various hydraulic control devices such as valves are provided. In addition, with the main purpose of preventing the occurrence of a locked state in individual wheels of a vehicle, abnormal changes in wheel rotational speed during braking due to changes in external conditions such as changes in the friction coefficient of the road surface are collected, and brake fluid pressure is measured. A so-called anti-skid type hydraulic pressure control device that controls the increase and decrease of the pressure is also provided.

By the way, I think that the latter type of device is preferable as a brake control device because it has excellent responsiveness to changes in external conditions, but on the other hand, it has disadvantages such as complicated structure, durability, and high cost. The current situation is that it has not yet been generalized.

In view of these problems, the present invention provides a new proportioning type hydraulic pressure control device that incorporates anti-skid type responsiveness to external conditions. That is, the present invention provides a proportion that controls the output hydraulic pressure to slowly increase at a corner point relative to the input hydraulic pressure by balancing the working hydraulic pressure from the input/output liquid chambers and the biasing spring force in the direction of the output liquid chamber. A shock valve mechanism, a G-valve mechanism that closes the flow path by a constant deceleration during vehicle braking, and seals a hydraulic pressure approximately proportional to the vehicle's carrying load in the sealing liquid chamber; a control spring whose spring force is increased in proportion to the hydraulic pressure value, and a boosting means for boosting the spring force of the control spring and transmitting the spring force to the control piston as an urging spring force; This is a deceleration sensing type hydraulic pressure control device, characterized in that it is provided with means for canceling or reducing the boosting ability of the boosting means by detecting an abnormal drop in rotational speed.

The present invention will be described below based on embodiments shown in the drawings.

In Fig. 1, 1 is a valve body, with anti-skid mechanisms and
It has a built-in proportioning valve mechanism and a G-valve mechanism, and a variable spring force adjustment mechanism for the control spring is built in the lower part, and the spring force of the control spring is controlled through a booster consisting of a seesaw ring on the right side. It is configured to transmit to the piston.

Proportioning valve mechanism 2 and 3 are stepped cylinders, and the control piston 4 is slidably fitted to the small diameter cylinder 2 at the tip, and the large diameter cylinder 3 at the rear end.
The inner cylinder member 5 is slidably fitted to the middle cylinder member 5. A second protrusion 29b of a seesaw link 29 as a boosting means described below is brought into contact with the rear end surface and pushed toward the tip side.

6 is an output liquid chamber facing the tip of the control piston 4;
Reference numeral 7 designates an input fluid chamber in which the control piston 4 shafts of the stepped portions of the stepped cylinders 2 and 3 are located; the former is connected and communicated with the rear wheel brake position via the output port 8, and the latter is connected to the input port 9 It is connected and communicated with a master cylinder, which is a hydraulic pressure source, through the hydraulic pressure source (this master cylinder is directly communicated with the front wheel brake system).

These input and output liquid chambers 6 and 7 are connected via a check valve mechanism built into the control piston 4, with reference numeral 10 representing a valve seat thereof, reference numeral 11 a valve body, and reference numeral 12 a pressing spring. In this check valve mechanism, normally (when not braking), the tip of the valve body 11 engages with the side wall of the cylinder 2 to open a flow path as shown in the figure, and the control piston 4 is moved to the right side of the figure (input When it moves to the liquid chamber 7 side), the flow path is closed by the contact between the valve body 11 and the valve seat 10, and after this, the flow path is opened and closed by the reciprocating movement according to the hydraulic balance of the control spring 4. .

Note that 13 is a sealing member that seals between the input and output liquid chambers 6 and 7, and 14 is a piston cup that prevents liquid from leaking toward the middle cylinder member 5 side.

The proportioning valve mechanism with the above configuration has a sliding cross-sectional area of the control piston 4 to the cylinder 2 and the middle cylinder member 5 that is A ₁ , A ₂ (A ₁ >A ₂ ) on the left side of the figure from the seesaw link part. Pressure force toward
If Fx is used, the input and output hydraulic pressures Pi and Po are controlled as follows.

A At the initial stage of braking, the input and output fluid chambers 6 and 7 are in communication, so Pi=Po B Px (Pi=Po)=Fx/A ₂ indicates the hydraulic pressure breaking point C After this, tanθ=A ₁ − At a ratio of A ₂ /A ₁ (<1), the output hydraulic pressure Po shows a lower increase than the input hydraulic pressure Pi. This example shows an example of a proportioning valve mechanism, and the above-mentioned control is It can also be replaced with an existing one of the same type.

G valve mechanism 15 is a valve chamber, and is communicated with the input liquid chamber 7 via a flow path 16. 17 is a ball having a weight of W; 18 is a guide surface for guiding the inertial movement of this ball 17, and is provided so as to form an elevation angle α with respect to the vehicle traveling direction shown by the arrow in the figure. 1
9 is a valve seat that closes the communication of the flow path 20 by contacting the ball 17 that moves inertia;
The flow path 20 normally communicates the valve chamber 15 and the sealing liquid chamber 21 .

The G valve mechanism having such a configuration is configured so that the flow path 20 is closed until the vehicle deceleration during braking reaches a certain value gc.
, and then closes the flow path 20, so that the brake fluid pressure at the time when the constant deceleration gc occurs is sealed in the sealing fluid chamber 21. Since the brake fluid pressure required to produce this constant deceleration gc is inversely related to the load carrying capacity of the vehicle, a higher hydraulic pressure is confined as the number of load carrying devices increases.

Incidentally, such a G valve mechanism can also be replaced with an existing electromagnetically actuated type.

The spring force adjustment and boost transmission mechanism 22 of the control spring is an adjustment piston, which is slidably fitted to the cylinder 23 forming the sealing liquid chamber 21 so that the tip part faces the sealing liquid chamber 21, and the rear end has a holding part. spring 2
4. Control spring 25 is engaged. 26
27 is a sealing member, and 27 is a stopper for the hold spring 24.

The rear end of the control spring 25 engages with the lower end of the seesaw link 29 via the spacer 28, and applies a spring force to the control piston 4 of the proportioning valve mechanism via the seesaw link 29. It is set up like this.

As shown in the figure, this seesaw link 29 has a length l ₂ from a central fulcrum projection 29a to a first projection 29 at the lower end that engages with the spacer 28, and a central fulcrum projection 29a that engages with the control piston 4. Second
If the length to the protrusion 29b is l ₁ (<l ₂ ), then l ₂ /
The spring force from the control spring 25 is amplified at a rate of ₁ and transmitted to the control piston 4.

The adjustment mechanism with such a configuration is moved by the balance between the liquid pressure sealed in the sealing liquid chamber 21 and the hold spring 24 and the control spring 25.
The spring force increased in accordance with this amount of movement is applied to the seesaw link 29, and the seesaw link 29
Since the biasing force is mechanically amplified in , the set load of the control spring 25 becomes smaller, and the cross-sectional area of the adjustment piston 22 becomes smaller, so the change in the volume of the sealing liquid chamber 21 does not become large. ,
It is also possible to prevent an unnecessary increase in the amount of fluid required, which would lead to an increase in the pedal stroke.

The anti-skid operating mechanism 30 is a liquid chamber interposed between the output liquid chamber 6 and the output port 8 of the proportioning valve mechanism, and is a normally closed liquid chamber formed by the rear end valve body 31a of the armature 31 and the valve seat 32. It is provided so that hydraulic pressure can be transmitted to the regulating liquid chamber 33 via the molded valve part.

This armature 31 normally comes into contact with the valve seat 32 by a pressure spring 34 to cut off communication between the liquid chamber 30 and the adjustment liquid chamber 33, and moves against the pressure spring 34 when the solenoid 35 is energized. It is provided to open a communication path. The operation of the solenoid 35 is controlled by a wheel rotational speed abnormal drop detector (not shown).
This is done, for example, by comparing vehicle speed and wheel rotation speed.

The adjusting piston 36 is provided in the adjusting liquid chamber 33.
The adjusting piston 36, whose front end faces toward the cylinder 37 and which is slidably fitted into the cylinder 37, is moved toward the right side in the figure (rear end According to the magnitude of the hydraulic pressure, a pressing force is applied to the third protrusion 29d at the upper end of the seesaw link 29 that engages with the rear end. 39 is a sealing member, and 40 is a spring seat.

The anti-skid operation mechanism with such a configuration is activated when an abnormal drop in wheel rotational speed occurs during vehicle braking, and when a skid state of the wheels is detected,
By energizing the solenoid 35 and moving the armature 31, fluid pressure is transmitted to the adjustment fluid chamber 33,
This hydraulic pressure can actuate the adjustment piston 36 to eliminate or reduce the biasing spring force boosting ability of the seesaw link 29.

Figure 2 shows the brake force control characteristics of the deceleration sensing type hydraulic pressure control device configured as described above. From when the car is empty to when the rear wheel brake force BR increases at a high rate when loaded, the actual brake force distribution state shown by the broken line in the figure is a sufficient approximation to the ideal brake force distribution state shown by the curve in the figure. It is understood that this can be achieved by

Furthermore, at point a in Fig. 2, the rear wheel brake force BR
It is shown that the brake force on the rear wheel decreases by a certain value, but this indicates that the anti-skid mechanism is activated, and the rear wheel brake force at this time
The reduction in BR is controlled by the degree to which the boosting ability of the boosting means is eliminated or reduced, the amount of movement of the adjustment piston 36, etc.

As described above, the deceleration sensing type hydraulic pressure control device according to the present invention efficiently performs the corner control of the rear wheel brake hydraulic pressure by the proportioning valve mechanism by the boosting means of the biasing spring force. In addition, by using an anti-skid mechanism in combination, it is possible to obtain a more desirable distribution of front and rear wheel brakes in response to changes in external conditions, and the practical benefits of this are extremely large. It is something.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of the device, and FIG. 2 is a diagram showing the characteristics of the braking force by the device. 1... Valve body, 2, 3... Cylinder, 4
... Control piston, 5 ... Middle cylinder member, 6...
...Output liquid chamber, 7...Input liquid chamber, 8...Output port, 9...Input port, 10...Valve seat,
11... Valve body, 13... Seal member, 14... Piston cup, 15... Valve chamber, 16... Channel, 17... Ball, 18... Guide surface, 19...
... Valve seat, 20 ... Channel, 21 ... Sealing liquid chamber, 22 ... Adjustment piston, 23 ... Cylinder,
24... Hold spring, 25... Control spring, 26... Seal member, 27... Stopper, 28... Spacer, 29... Seesaw link, 29a... Fulcrum projection, 29b... Second projection,
29c...first protrusion, 29d...third protrusion, 30
...Liquid chamber, 31...Amateur, 31a...Valve body part, 31...Valve seat, 33...Adjustment liquid chamber,
34...Press spring, 35...Solenoid,
36... Adjustment piston, 37... Cylinder, 38
... Adjustment spring, 39 ... Seal member, 40
...Spring seat.

Claims (1)

[Claims] 1 The control piston, which faces the input and output liquid chambers with different hydraulic pressure receiving areas, moves due to the balance between the biasing spring force acting on the control piston, which resists the liquid pressure in the input liquid chamber, and the liquid pressure from these liquid chambers. A proportioning valve mechanism that controls the output hydraulic pressure at a turning point and a gradual increase with respect to the input hydraulic pressure, and a proportioning valve mechanism that closes the flow path by constant deceleration when the vehicle is braked and stores it in the sealing liquid chamber according to the vehicle's load capacity. A G valve mechanism that seals in a proportional value of hydraulic pressure, a control spring whose spring force is increased in proportion to the hydraulic pressure value sealed in the sealing liquid chamber, and a control spring that doubles the spring force of this control spring and The invention is characterized by comprising a booster that transmits a biasing spring force to a control piston, and an anti-skid operating mechanism that detects a skid state of a wheel of a vehicle and eliminates or reduces the boosting ability of the booster. Deceleration sensing type hydraulic control device.