JPH03263B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention is directed to a braking system for a vehicle in which a tandem master cylinder is used to configure two independent braking hydraulic circuits. Regarding the hydraulic control device, in particular, there is a common housing interposed in the middle of the first and second flow paths that separately supply the output hydraulic pressure of the master cylinder to a pair of left and right rear wheel brakes; and a cylinder hole formed in this housing. a pair of left and right pressure receiving pistons that slide together and define, on each outer end side, first and second output hydraulic chambers communicating downstream of the first and second flow paths; formed on each of the pressure receiving pistons; Each slides into a small cylinder hole of the same diameter,
a valve moving piston defining first and second input hydraulic chambers communicating upstream of the first and second flow paths, respectively, on each outer end side; capable of coming into contact with each pressure receiving piston and the valve moving piston; a pair of left and right spacers that define the limits of movement of the pistons; a common pressure regulating spring that is compressed between the spacers; a communicating hole formed; a valve that opens and closes the communicating hole by sliding of each of the pressure receiving pistons, and is moved by movement of the valve moving piston over a predetermined distance to keep the communicating hole open; The present invention relates to an improvement of a brake hydraulic control device for a vehicle equipped with;

(2) Prior art This braking hydraulic control device is disclosed in Japanese Patent Application Laid-Open No. 57-175451.
It is disclosed in the publication No.

(3) Problems to be solved by the invention In the brake hydraulic control device disclosed in the above publication,
The valve movement piston is held in the neutral position by the repulsive force of the pair of valve springs that bias the left and right valves in the valve closing direction, so in order to maintain the neutral position, the set load of the valve springs must be applied. It must be set to a large extent. However, if this is done, the opening pressure of the valve becomes high, which has the disadvantage of making it difficult to open the valve due to the hydraulic pressure in the output hydraulic chamber when the brake is released.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a simple and effective braking hydraulic control device capable of holding a valve moving piston in a neutral position without adversely affecting the valve opening characteristics of the valve. shall be.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a flange portion at the outer end of the spacer to be held between the pressure receiving piston and the pressure regulating spring. Shoulders facing the outer surface of the flange portion are provided on the inner periphery of the pressure receiving piston and the outer periphery of the valve moving piston, respectively, and a disc portion that abuts on the both shoulders is provided between the shoulder portions and the flange portion. It is characterized by interposing a neutral spring consisting of a resilient piece cut and raised from the disk portion and pressed into contact with the flange portion.

(2) Effect By providing the neutral spring, the valve moving piston can be held at the neutral position without changing the opening characteristics of the valve.

Moreover, since the disc portion of the neutral spring plays the role of a washer that abuts the shoulder portions of the pressure receiving piston and the valve moving piston to define the neutral position of the valve moving piston, a dedicated washer is not required.

(3) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. In FIG.
During operation, a pair of front and rear pistons 2 in the cylinder
₁ and 2 ₂ are respectively the first and second output ports P ₁ ,
Pressure oil can be supplied from P ₂ to the first and second flow paths L ₁ and L ₂ . This pressure oil is led to the front wheel brakes Bf, Bf' and the brake hydraulic control device C.

The housing 3 of the brake hydraulic control device C has a cylinder hole 4 with one end open.
The open end of is closed by a screw plug 5. Two pressure receiving pistons 6 ₁ and 6 ₂ having the same diameter are slid into this cylinder hole 4 . Each pressure receiving piston 6
₁ and 6 ₂ have small cylinder holes 7 ₁ and 7 ₂ of the same diameter.
are formed, and these small cylinder holes 7 ₁ ,
Valve moving pistons 8 ₁ and 8 ₂ whose back surfaces are in contact with each other are respectively slid on 7 ₂ . A common pressure regulating spring 10 is compressed between both pressure receiving pistons 6 ₁ and 6 ₂ via spacers 9 ₁ and 9 ₂ . These spacers 9 ₁ , 9 ₂ each have a flange portion 9 a held between the pressure receiving piston 6 ₁ , 6 ₂ and the pressure regulating spring 10 at its outer end, and a flange portion 9 a facing the outer end surface of each flange portion 9 a. and the pressure receiving piston 6 ₁ ,
Shoulders 6a and 8a are formed on the inner periphery of valve moving piston 6 ₂ and on the outer periphery of valve moving pistons 8 ₁ and 8 ₂ , respectively. Neutral springs 11 ₁ and 11 ₂ are interposed between the shoulders 6a and 8a and the flange 9a. As shown in FIG. 2, each of the neutral springs 11 ₁ and 11 ₂ includes a disk portion 11a that abuts both the shoulders 6a and 8a, and a plurality of neutral springs cut and raised from the disk portion 11a and pressed against the flange portion 9a. It is composed of an elastic piece 11b.

First and second input hydraulic pressure chambers 13 _{1 , 13 2 are formed in both the small cylinder holes 7 1 , 7 2 by the respective outer ends of the valve moving pistons 8 1 , 8 2 , and in both} ends of the cylinder hole 4 . The outer ends of both pressure receiving pistons 6 ₁ and 6 ₂
and second output hydraulic chambers 14 ₁ , 14 ₂ are respectively defined, and the pressure receiving area of each output hydraulic chamber 14 ₁ , 14 ₂ side of each pressure receiving piston 6 1 , 6 ₂ is equal to that of each input hydraulic chamber 13 ₁ , 14 ₂ . 13 It is larger than the pressure receiving area on _{the 2} side.
These first and second input hydraulic chambers 13 ₁ , 13 ₂ are connected to the upstream side of the first and second flow paths L ₁ , L ₂ via inflow ports 15 ₁ , 15 ₂ , and to the first and second input hydraulic chambers 13 1 , 13 2 . The output hydraulic chambers 14 ₁ , 14 ₂ have outflow ports 16 ₁ , 1
The downstream channels of both channels L ₁ and L ₂ are connected to each other through the channel 6 ₂ so as to be in constant communication with each other.

The end walls of the small cylinder holes 7 ₁ and 7 ₂ are provided between adjacent input and output hydraulic chambers 13 ₁ and 14 ₁ and between 13 ₂ and 14 _{2 .}
Communication holes 17 ₁ and 17 ₂ are formed to communicate between the valve ₁ and the valve ₁ .
Valve opening rods 19 protruding from the outer ends of 8 ₁ and 18 ₂ , respectively.
_1,192 can penetrate through it _.

Each valve 18 ₁ , 18 ₂ and valve moving piston 8
Valve springs 20 ₁ and 20 ₂ are compressed between the valves 1 and 8 ₂ , respectively, and normally the valve opening rods 19 ₁ and 19 ₂ of the valves 18 _{1 and} 18 ₂ are connected to the end wall of the cylinder hole 4 and the screw. The valves 18 ₁ and 18 ₂ are held in the open position by abutting against the inner ends of the plugs 5 and at the limits of outward sliding of the respective pressure receiving pistons 6 ₁ and 6 ₂ . The pressure receiving pistons 6 ₁ , 6 ₂ move inward and open the small cylinder holes 7 ₁ , 6 2 .
When the valves 18 ₁ and 18 ₂ are seated on the end wall of 7 ₂ ,
The communication holes 17 ₁ and 17 ₂ are closed.

A connector 21 is attached to the inner end of each valve 18 ₁ , 18 ₂ .
₁ and 21 ₂ are connected together. The inner ends of these connectors 21 ₁ , 21 ₂ are connected to stoppers 22 provided at the outer ends of the valve moving pistons 8 ₁ , 8 ₂ when the valve moving pistons 8 ₁ , 8 ₂ move inward by a predetermined distance l ₂ . ₁ , 22 ₂ . This distance l ₂ is larger than the distance l ₁ that the pressure receiving pistons 6 ₁ and 6 ₂ move from the open position to the closed position of the valves 18 ₁ and 18 ₂ , and this distance l ₁ and
The sum of the distance l 3 that the valve moving pistons 8 ₁ and 8 ₂ move from the neutral position to the position where they contact the flange portions 9a of the spacers _{9 1 and 9 2 via} the disk portions 11a of the neutral springs 11 1 and _{11 2} is set smaller than.
That is, l ₁ < l ₂ < l ₁ + l ₃ .

A discharge hole 23 is provided in the side wall of the intermediate portion of the housing 3 that accommodates the pressure regulating spring 10, and this discharge hole 23 is normally closed with a rubber stopper 24.
This rubber plug 24 is designed to prevent hydraulic fluid from leaking from the input hydraulic chambers 13 ₁ , 13 ₂ due to damage to the sealing members around the pressure receiving pistons 6 ₁ , 6 ₂ and the valve moving pistons 8 ₁ , 8 ₂ . It is designed to rupture or separate due to the pressure of the oil, and if the rupture or separation occurs, leaked hydraulic oil will flow out from the discharge hole 23, so damage to the seal member can be avoided in the reservoir of the master cylinder M. It can be detected as an abnormal drop in the oil level.

Next, the operation of this embodiment will be explained.
When the master cylinder M is not operating, both the left and right pressure receiving pistons 6 ₁ and 6 ₂ are pressed to the outward sliding limit shown in FIG. 1 by the set load of the pressure regulating spring 10.
The valves 18 ₁ and 18 ₂ are open, respectively, and between the first and second input and output hydraulic chambers 13 ₁ and 14 ₁ and 1
3 ₂ and 14 ₂ are in communication with each other. Also,
The valve moving pistons 8 ₁ , 8 ₂ have neutral springs 11 ₁ ,
The disc part 11a of ₁₁₂ comes into contact with the pressure receiving pistons ₆₁ , ₆₂ and both shoulder parts 6a, _8a of the valve moving pistons ₈₁ , 82 with the repulsive force of the elastic piece 11b, and is brought to the neutral position. Retained.

When the brake pedal 1 is operated here, the output hydraulic pressure of the master cylinder M flows through the first and second flow paths L ₁ ,
It is transmitted to each downstream of L ₂ , and the front and rear brakes Bf,
Bf′, Br, and Br′ operate simultaneously.

Then, as the output oil pressure of the master cylinder M increases, the first and second input and output oil pressure chambers 13 ₁ , 14 ₁
The pressure inside the pressure receiving pistons 6 ₁ , 14 ₂ also rises, but when the pressure reaches a certain value, the pressure receiving areas of the pressure receiving pistons 6 ₁ , 6 ₂ increase due to the difference in the pressure receiving areas on the inside and outside of the pressure receiving pistons 6 ₁ , 6 2 .
The differential oil pressure acting on 6 ₂ becomes larger than the set load of the pressure regulating spring 10, and the pressure receiving pistons 6 ₁ and 6 ₂
Each moves inward while compressing the pressure regulating spring 10.

During this time, if any pressure difference occurs between the left and right input hydraulic chambers 13 ₁ , 13 ₂ , the valve moving pistons 8 ₁ , 8 ₂ will shift from the neutral position shown in the figure to the resilient pieces of the neutral springs 11 ₁ , 11 ₂ . 11b while deforming it, slightly move it to the lower pressure side, and both input hydraulic chambers 13
₁ , 13 Balance the pressure of ₂ . Even during such movement, the valve moving pistons 8 ₁ and 8 ₂ keep the valve spring 2
0 ₁ , 20 ₂ to press the valves 18 ₁ , 18 ₂ outward, and hold the valve opening rods 19 ₁ , 19 ₂ in contact with the end wall of the cylinder hole 4 and the inner end of the screw plug 5. .

Therefore, each pressure receiving piston 6 ₁ , 6 ₂ has a distance l ₁
When the valves 18 ₁ and 18 2 have moved inward by a certain amount, the valves 18 1 and 18 ₂ close the communicating holes 17 ₁ and 17 ₂ . As a result, during this period, the oil pressure in the output oil pressure chambers 14 ₁ and 14 ₂ , that is, the braking oil pressure for the rear wheels, is stopped from increasing.

When the output hydraulic pressure of the master cylinder M further increases, the pressure within the input hydraulic chambers 13 ₁ and 13 ₂ increases, pushing each pressure receiving piston 6 ₁ and 6 ₂ outward.
Therefore, the valves 18 ₁ , 18 ₂ open again, increasing the pressure in the output hydraulic chambers 14 ₁ , 14 ₂ . When this pressure reaches a certain value, the pressure receiving piston 6 ₁ ,
6 ₂ is activated again, the communication holes 17 ₁ and 17 ₂ are closed, and the increase in pressure is stopped. By repeating this action, the braking oil pressure for each rear wheel is
It is assumed that the output hydraulic pressure of the master cylinder M is reduced at a constant ratio.

On the other hand, since the output hydraulic pressure of the master cylinder M directly acts on the front wheel brakes Bf, Bf', the braking hydraulic pressure of the front wheels rapidly increases as the output hydraulic pressure of the master cylinder M increases. In this way, when braking is applied strongly, the vehicle body leans forward and the brakes Bf and Bf′ are applied more strongly to the front wheel on the side where the downward load increases, while the brakes Bf and Bf′ are applied more strongly to the rear wheel on the side where the load decreases. Since the brakes Br and Br′ will be operated weakly,
Efficient braking can be performed without causing skidding in each wheel.

Next, one of the systems in the brake hydraulic circuit, for example the second flow path _L2 side, breaks down and the rear wheel brake
Suppose that braking hydraulic pressure is no longer applied to the hydraulic operating part of Br′. At this time, when the brake pedal 1 is operated, the output oil pressure of the master cylinder M is changed to the first flow path _L1.
The pressure in the first input hydraulic pressure 13 ₁ increases, but the pressure in the second input hydraulic pressure chamber 13 ₂ does not increase. Therefore, both the valve moving pistons 8 ₁ and 8 ₂ move to the right in the figure, and the left valve moving piston 8 ₁ moves toward the disk portion 1 of the neutral spring 11 ₁ .
It contacts the flange portion 9a of the spacer ₉₁ via 1a. As the valve moving piston 8 ₁ moves, the pressure regulating spring 10 is applied via the spacer 9 ₁ .
Compress.

As a result, the pressure receiving piston 6 ₁ has a pressure regulating spring 10
Since the pressing force is no longer applied, the piston 6 ₁ moves inward due to the differential pressure from the inside and outside.

When the valve moving pistons 8 ₁ , 8 ₂ move to the right by a predetermined distance l ₂ , the stoppers 22 ₁ at their outer ends move.
engages the inner end of connector 21 ₁ and moves valve 18 inwardly. Since the distance l ₂ is set smaller than l ₁ + l ₃ , the valve 18 ₁
is apart from the end wall of the small cylinder hole ₇₁ , and maintains an open state.

In this way, the valve moving piston 8 ₁ and the valve 18
_1. The pressure receiving piston 6 ₁ moves inward to a position where the inner end of the spacer 9 ₁ abuts the inner end of the other spacer 9 ₂ .

The valve moving piston 8 ₁ is the innermost, that is, the first
When the spacers 9 ₁ and 9 ₂ move to the right in the figure and the inner ends of the spacers 9 1 and 9 2 are in contact with each other, the pressure receiving piston 6 ₁ is also moved to a position where its inner ends are in contact with the flange portion 9a of the spacer 9 ₁ . However, since the stopper 22 ₁ is engaged with the inner end of the connector 21 ₁ at this time, the valve 18 ₁ continues to open the communication hole 17 ₁ .
Therefore, the output oil pressure of the master cylinder M is directly transmitted to the first output oil pressure chamber 141, and the output oil pressure of the master cylinder M is directly transmitted to the first output oil pressure chamber ₁₄₁ , and
The rear wheels of the _L1 side system will be braked with the same strength as the front wheels. In other words, when one system fails, this brake hydraulic control device C operates in the same way as when this control device C is not installed, without reducing the rear wheel brake hydraulic pressure for the other system. This means that the brake hydraulic control device C is provided with a bypass function.

When the master cylinder M is returned to the inactive state to release the brake, the input hydraulic chambers 13 ₁ , 13 ₂
At this time, the pressure receiving pistons 6 ₁ , 6 ₂
is in the inward movement position and the valves 18 ₁ and 18 ₂ are closed, the oil pressure in the output oil pressure chambers 14 ₁ and 14 ₂ becomes relatively higher than the oil pressure in the input oil pressure chambers 13 ₁ and 13 ₂ . However, such input and output hydraulic chambers 13 ₁ , 1
The valves 18 _{1 and 18 2 are opened due to the pressure difference between 4 1 and} between 13 ₂ and 14 ₂ , and the communication holes 17 ₁ and 17 ₂ are opened _.
to open. As a result, the output hydraulic chambers 14 ₁ , 14 ₂
The rear wheel brakes Br and Br′ can also be deactivated by reducing the pressure.

In this case, the set loads of the valve springs _{20 1} , 20 ₂ that determine the opening pressure of the valves 18 1 , 18 ₂ can be set regardless of the neutral springs 11 ₁ , 11 ₂ , so that the set loads are suitable for the valves 18 ₁ , 18 ₂ . It is possible to provide suitable valve opening characteristics.

In the above embodiment, the valve moving pistons 8 ₁ and 8 ₂ are divided into left and right parts, but they can be integrated into one piece if there are no assembly problems.

C. Effects of the Invention As described above, according to the present invention, the outer end of the spacer is provided with a flange portion which is held between the pressure receiving piston and the pressure regulating spring, and the shoulder portion facing the outer surface of the flange portion is connected to the pressure receiving piston. and the outer circumference of the valve moving piston, and between the shoulders and the flange, there is a disc part that comes into contact with the shoulders, and a disc part that is cut and raised from the disc part and press-fitted to the flange part. Since a neutral spring consisting of a resilient piece is provided, the valve moving piston can be held at the neutral position without changing the valve opening characteristics of the valve.

In addition, the disk portion of the neutral spring functions as a washer that comes into contact with the shoulder portions of the pressure receiving piston and the valve moving piston to define the neutral position of the valve moving piston, so a dedicated washer is not required.
This can contribute to simplifying the structure by minimizing the increase in the number of parts.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view showing a brake hydraulic control device together with a brake hydraulic circuit of an automobile, and FIG. 2 is a perspective view of a neutral spring in the brake hydraulic control device. . Br, Br'... Rear wheel brake, C... Braking hydraulic control device, M... Master cylinder, 3... Housing, 4... Cylinder hole, 6 ₁ , 6 ₂ ... Pressure receiving piston, 6a... Shoulder part , 7 ₁ , 7 ₂ ... small cylinder hole,
8 ₁ , 8 ₂ ... Valve moving piston, 8a ... Shoulder section, 9 ₁ , 9 ₂ ... Spacer, 9a ... Flange section, 10 ... Pressure regulating spring, 11 ₁ , 11 ₂ ... Neutral spring, 11a ...Disc part, 11b...Bullet piece, 13
₁ , 13 ₂ ...first and second input hydraulic chambers, 14 ₁ , 1
4 ₂ ... first and second output hydraulic chambers, 15 ₁ , 15 ₂ ...
...Inflow port, 16 ₁ , 16 ₂ ...Outflow port, 1
7 ₁ , 17 ₂ ... Communication hole, 18 ₁ , 18 ₂ ... Valve, 19 ₁ , 19 ₂ ... Valve opening rod, 20 ₁ , 20 ₂ ...
Valve spring, 21 ₁ , 21 ₂ ... Connector, 22 ₁ , 2
2 ₂ ...stoppa.

Claims (1)

[Scope of Claims] 1. A common housing interposed in the middle of the first and second flow paths that separately supply the output hydraulic pressure of the master cylinder to the left and right rear wheel brakes; a cylinder hole formed in this housing; a pair of left and right pressure receiving pistons that slide together and define, on each outer end side, first and second output hydraulic chambers communicating downstream of the first and second flow paths, respectively; formed on each of the pressure receiving pistons; a valve moving piston that slides into a small cylinder hole of the same diameter and defines, on each outer end side, first and second input hydraulic pressure chambers communicating upstream of the first and second flow paths; a pair of left and right spacers that can come into contact with the pressure receiving piston and the valve moving piston and define the limits of movement of these pistons; a common pressure regulating spring that is compressed between the spacers; and each adjacent input and output hydraulic chamber. a communication hole formed in each of the pressure receiving pistons so as to communicate therebetween; the communication hole is opened and closed by sliding of each of the pressure receiving pistons, and is moved by movement of the valve moving piston over a predetermined distance; , a valve that keeps the communication hole open; and a flange portion held between the pressure receiving piston and the pressure regulating spring is provided at the outer end of the spacer, and the flange portion is provided at the outer end of the spacer. A shoulder portion facing the outer surface of the pressure receiving piston and an outer circumference of the valve moving piston are provided respectively on the inner periphery of the pressure receiving piston and the outer periphery of the valve moving piston. It is characterized by interposing a neutral spring consisting of a resilient piece cut and raised from the disc part and pressed against the flange part,
Vehicle brake hydraulic control device.