JPS5848218Y2 - Deceleration responsive hydraulic control valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a deceleration-responsive hydraulic pressure control valve that controls the brake fluid pressure transmitted to the rear wheel brakes in response to the deceleration occurring in the vehicle when the vehicle zero brake is activated. .

Conventionally, one of these is a small pressure-receiving surface that receives hydraulic pressure from an inlet chamber connected to the master cylinder, and a large pressure-receiving surface that receives hydraulic pressure from an outlet chamber connected to the rear wheel brake, facing each other. a stepped piston; and a valve means that opens and closes a liquid passage between the inlet chamber and the outlet chamber by movement due to a pressing force difference between hydraulic pressures acting on both pressure receiving surfaces of the stepped piston;
a control chamber connected to the inlet chamber via a preload spring that presses the stepped piston in a direction to open the valve means; and a deceleration responsive valve that closes in response to deceleration of the vehicle; There is a deceleration-responsive hydraulic pressure control valve that includes a control piston that increases the biasing force of the preload spring in accordance with the hydraulic pressure in the control chamber when the deceleration-responsive valve is closed.

Conventionally, this type of deceleration-responsive hydraulic pressure control valve optimally controls the hydraulic pressure supplied to the rear wheel brakes depending on the loading condition of the vehicle, for example, whether it is fully loaded or fully loaded.
The control start fluid pressure is determined based on the brake fluid pressure when the vehicle deceleration reaches a predetermined value, and when the brake fluid pressure supplied from the master cylinder reaches the control start fluid pressure, the brake fluid pressure is supplied from the master cylinder. Brake fluid is supplied directly to the rear brakes, and when the hydraulic pressure exceeds the control start hydraulic pressure, the hydraulic pressure supplied to the rear brakes is reduced to a predetermined ratio with respect to the hydraulic pressure from the master cylinder.

However, the ratio of the rear wheel brake hydraulic pressure to the master cylinder side hydraulic pressure above the control start hydraulic pressure is always kept at a predetermined ratio regardless of the magnitude of the control start hydraulic pressure determined by the vehicle deceleration. So, for example, if you set the ratio according to the fully loaded state of the vehicle, the ratio will be too small when the vehicle is fully loaded, especially if the load is concentrated on the rear axle of the vehicle and the effectiveness of the chassis or brakes becomes poor. However, there was a drawback that sufficient brake fluid pressure could not be supplied to the rear wheel brakes.

The present invention has been made in view of the above drawbacks, and provides a deceleration-responsive hydraulic pressure control valve that can supply higher brake fluid pressure to the rear wheel brakes when a large braking force is required for the rear wheel brakes. The purpose of the invention is to provide a liquid passage that directly connects the inlet chamber and the control chamber by bypassing the deceleration response valve, and that the liquid passage is connected to the liquid pressure of the inlet chamber. and a second pressure receiving surface receiving the hydraulic pressure of the control chamber, and the sum of the pressing forces due to the respective hydraulic pressures acting on the first pressure receiving surface and the second pressure receiving surface is greater than the biasing force of the valve spring. This is due to the provision of a bypass valve that opens when this happens.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

In the figure, 1 is a tandem master cylinder operated by a brake pedal 2, and an independent f
? Equipped with two hydraulic pressure generating chambers, one of the hydraulic pressure generating chambers is connected to the front wheel brake equipment 5, 5 via piping 3, 4.4'.
', and the other hydraulic pressure generating chamber is connected via piping 6 to a deceleration-responsive hydraulic pressure control valve, generally designated by 1, and then to the rear wheel brake system via piping 9, 10, and 10'. 11°11'.

12 is a main body of the deceleration responsive hydraulic pressure control valve I, and a first cylinder hole 13. A stepped piston 18 having a second cylinder hole 14 and a hole 15, and a large diameter portion 16 and a small diameter portion 17 in the first cylinder hole 13. A control piston 19 is slidably inserted.

The stepped piston 18 has a left side portion of the small diameter portion 17 fitted into a hole 38 formed in the control piston 19, and a valve member 21 in a valve chamber 20 provided on the right side portion.
．． A valve spring 23 is provided that presses the valve member 21 against the valve seat 22.

The valve member 21 and the valve seat 22 constitute a valve means.

An outlet chamber 24 defined on the right side of the stepped piston 18 is connected to the piping 9 through a connection port 25 and is connected to a liquid passage 26.
．． An inlet chamber 21 communicating with the valve chamber 20 via valve means (21, 21) and defined between the stepped piston 18 and the control piston 19 is connected to a liquid passage 28. Hole 15. It is connected to the piping 6 through a connection port 29 and communicates with the valve chamber 20 through a liquid passage 30 .

The retaining ring 3 is fitted into the left end of the first cylinder hole 13 in the housing.
A control chamber 33 defined between the blind cover 32 and the control piston 19, which is prevented from being pulled out by 1, communicates with the bore 15 by a liquid passage 34,35.

An air chamber 36 is formed inside a hole 37 bored in the stepped piston 18 and a hole 38 in the control piston 19.

The preload spring 39 is arranged with its tension, that is, a biasing force, set between a spring receiver 41 that is in contact with the stepped portion 40 of the stepped piston 18 and a spring receiver 42 that is still in contact with the right end of the control piston 19; The stepped piston 18 is pushed to the right in the figure, the right end of the stepped piston 18 is brought into contact with the right end wall of the cylinder hole 13, and the valve member 21 is moved away from the valve seat 22.

43, 44, 45, and 46 are sealing materials, respectively.

47 is a stepped portion provided in the first cylinder hole 13, and functions as a stopper to limit the amount of rightward movement of the control piston 19.

An adjustment spring 48 is set to a smaller force than the preload spring 39, and adjusts the pushing force of the preload spring 39 that pushes the control piston 19 to the left.

50 is a ball valve, and the guide member 5 is installed in the hole 15.
The valve seat 53 is arranged so as to be able to slide or roll on the guide surface 52 of the valve 1, and can be seated on a valve seat 53 provided at the right end of the liquid passage 35.
The ball valve 50 and the valve seat 53 constitute a deceleration responsive valve.

Reference numeral 54 denotes a support member for supporting the valve seat 53, the left end portion of which is press-fitted into the liquid passage 35, and has a liquid passage 55 therein.

Reference numeral 56 denotes a blind lid, which is provided with a sealing material 5γ on the outer periphery and closes the hole 1.
5 and is prevented from being removed by a retaining ring 58.

60 is a bypass valve member, which is connected to the second cylinder hole 14
A chamber 62 and a liquid passage 3 are slidably inserted into the 20th cylinder hole 14 and communicate with the hole 15 via a liquid passage 61.
The bypass valve member 6 is divided into a chamber 63 communicating with the bypass valve member 6.
0, the sealing material 68, and the stepped portion of the second cylinder hole 140 constitute a bypass valve γ1, and when the bypass valve member 60 is in the right position in the figure, the chamber 62 and the chamber 63 are shut off,
When moving to the left, the chambers 62 and 63 are communicated with each other.

υL When the bypass valve 71 is pressed, the right end surface 60b of the bypass valve member 60 forms a first pressure receiving surface that receives the liquid pressure supplied to the hole 15 via the liquid passage 61, and the chamber 6
A second pressure-receiving surface that receives the hydraulic pressure supplied to the control chamber 33 via the liquid passage 34 is formed by the stepped portion 60a provided on the bypass valve member 60 facing 3.

Reference numeral 64 denotes a spring, which is inserted with its tension set to a predetermined value between a spring receiver 65 in contact with one end of the bypass valve member 60 and a spring receiver 6γ whose removal is prevented by a retaining ring 66. ing.

69 is a sealing material.

Then, the main body 12 is attached to the vehicle body through a mounting hole 10°70' so that the left side faces the front of the vehicle and the guide surface 52 of the guide member 51 is at an angle θ with respect to the horizontal plane H. It is being

This angle O is set so that when a preset deceleration occurs in the vehicle, the ball valve 50 moves to the left on the inclined surface and seats on the valve seat 53, thereby blocking the liquid passage 55 from the hole 15. ing.

Next, the operation will be explained.

Brake pedal 2 for the driver to brake the vehicle
When the pedal is depressed, brake fluid pressure corresponding to the pedaling force is generated in each hydraulic pressure generating chamber of the master cylinder 1, and the brake fluid in one of the hydraulic pressure generating chambers passes through the pipe 3°4.4' and is delivered to the front wheel brake device 5. , 5', and brakes are applied to the front wheels.

At the same time, the brake fluid in the other hydraulic pressure generation chamber is
The liquid is supplied into the hole 15 through the connection port 29, and is further connected to the liquid passage 2.
8 into the inlet chamber 27.

Is the deceleration of the vehicle a predetermined value, for example 0.31? (
When the brake fluid pressure is lower than the control start fluid pressure (described later), the stepped piston 18 is biased to the right by the tension of the preload spring 39;
Since its right end is in contact with the right end wall of the first cylinder hole 13 and the valve member 21 is separated from the valve seat 22, the inlet chamber 2T
The brake fluid supplied to the fluid passage 30. Valve chamber 20. The liquid is supplied to the outlet chamber 24 through the passage 26, and from the connection port 25 through the pipes 9, 10, 10' to the rear wheel brake device 11.1.
1', and the brake is applied to the rear wheels.

At the same time, the brake fluid supplied into the bore 15 is supplied to the control chamber 33 through the fluid passage 55.35, since the ball valve 50 is in the position shown.

Therefore, the same brake fluid pressure acts on the control piston 19 from both sides, but the inlet chamber 2 of the control piston 19
Since the pressure receiving surface facing T is smaller than the pressure receiving surface facing the control chamber 33 by the cross-sectional area S1 of the small diameter portion 17 of the stepped piston 18, if the brake fluid pressure is P, the control piston 1
9 receives the pressing force of Sl·P to the right.

When this pressing force S1·P becomes larger than the tension obtained by subtracting the set tension of the adjustment spring 48 from the set tension of the preload spring 39, the control piston 19 compresses the preload spring 39 and moves to the right. The tension of the load spring 39 is increased to increase the biasing force that biases the stepped piston 18 to the right.

The brake fluid pressure at which the control piston 19 begins to move to the right can be adjusted by appropriately setting the tension of the adjustment spring 48.

Moreover, the bypass valve member 60 has a chamber 63 at its stepped portion 60a.
The right end surface 60b receives the liquid pressure of the chamber 62 supplied through the liquid passage 61.

However, since the tension of the spring 64 is set to be sufficiently large, when the brake fluid pressure reaches a sufficiently high predetermined value, which will be described later, the bypass valve member 60 is maintained in the state shown in the figure, and the chamber 6
2 and the chamber 63 are cut off.

When the brake pedal 2 is strongly depressed and the deceleration of the vehicle reaches a predetermined value, the ball valve 50 moves to the left by its inertia force against the inclination angle θ of the guide member 510 and the guide surface 52. It is seated on the valve seat 53 to block the fluid passage 55 from the inside of the hole 15, stopping the supply of fluid to the control chamber 33 and the chamber 63, and sealing the brake fluid in each chamber.

Therefore, even if the brake fluid pressure supplied to the hole 15 and the inlet chamber 2T increases more than that, no more brake fluid will be supplied to the brake chamber 33, and the control piston 1
9, the vehicle stops at a position determined by the hydraulic pressure when the deceleration of the vehicle reaches a predetermined value.

That is, the biasing force of the preload spring 39 that biases the stepped piston 18 to the right increases or decreases depending on the brake fluid pressure supplied to the control chamber 33, and when the deceleration of the vehicle reaches a predetermined value. Since its value is limited by the hydraulic pressure of When the vehicle is fully loaded or close to fcl/i, the brake fluid pressure is high when the deceleration reaches a predetermined value, and the biasing force of the preload spring 39 is set to be large.

The brake fluid pressure supplied to the inlet chamber 27 further increases, and the force pushing the stepped piston to the left, that is, the stepped piston 18
The hydraulic pressure S2·P of the outlet chamber 24 acting on the cross-sectional area S2 of the large-diameter portion 16 of The hydraulic pressure (of the inlet chamber 27) acting on the area difference (S2-81)
S2-81), the sum of P and the biasing force F of the preload spring 39 (
S2-8t) When the value becomes larger than P+F, the stepped piston 18 moves to the left, and the valve member 21 is seated on the valve seat 22 by the tension of the valve spring 23, thereby preventing liquid communication between the inlet chamber 27 and the outlet chamber 24. The rear wheel brake device 1 is shut off from the exit chamber 24.
1. Begin controlling the brake fluid pressure supplied to 11'.

(At this time, the amount of liquid in the control chamber 33 is maintained at the same level as when the ball valve 50 was closed, and the tension of the preload spring 39 remains unchanged.)
From the above relationship, this control start hydraulic pressure PC is determined by S2・PC
=(S2-81)*PC+F'PC2F/S1, and is proportional to the biasing force F of the preload spring 39.

Therefore, the control start hydraulic pressure is determined according to the brake hydraulic pressure when the deceleration of the vehicle reaches a predetermined value.

Then, when the brake fluid pressure supplied to the inlet chamber 27 further increases from the control start fluid pressure, the stepped piston 18 moves to the right due to the increased fluid pressure, and the valve member 21 moves toward its valve seat 22.
and transmits the hydraulic pressure in the inlet chamber 27 to the outlet chamber 24.

As a result, the hydraulic pressure in the outlet chamber 24 increases, and the stepped piston 1
8 to the left again to cut off fluid communication between both chambers 27, 24.

By repeating this operation, the brake fluid pressure in the outlet chamber 24 is controlled.

The increase in the brake fluid pressure in the outlet chamber 24 is caused by the increase in the brake fluid pressure in the outlet chamber 24.
If the brake fluid pressure in the outlet chamber 24 is PI and the brake fluid pressure in the outlet chamber 24 is PO, then S2・PO=(S2−8l)・P1+
F, the increase in hydraulic pressure in the inlet chamber 24 (S2-81)/S
reduced to 2.

If the brake effectiveness deteriorates or the rear axle becomes overloaded due to thermal fading of the lining of the brake system, even higher brake fluid pressure is supplied from the tandem master cylinder 1 to the hole 15, and the fluid pressure increases. When reaches a predetermined value that is half as high as above, the hydraulic pressure in the chamber 63 acting on the stepped portion 60a of the bypass valve member 60 and its right end surface 60bK
Since the sum of the applied hydraulic pressure in the chamber 62 becomes greater than the set tension of the spring 64, the bypass valve member 60 moves to the left against the tension of the spring 64, opens the bypass valve, and closes the chambers 62 and 63. The high brake fluid pressure in the hole 15 is communicated with the fluid passage 61. Rooms 62, 63. Control room 33 through liquid passage 34
supply to.

That is, the deceleration responsive valve 50.53 is bypassed and the hole 1 is
5 is directly transmitted to the control chamber 33.

Therefore, the control piston 19 compresses the preload spring 39 by its hydraulic pressure and moves to the right, increasing the biasing force of the preload spring 39 and increasing the brake hydraulic pressure transmitted to the outlet chamber 24. Apply more effective braking to the rear wheel brakes.

The hydraulic pressure that pushes the bypass valve member 60 to the left is the hydraulic pressure within the control chamber 33 limited by the deceleration responsive valves 50 and 53 acting on the stepped portion 60a and the right end surface 60b.
The brake fluid pressure when operating the bypass valve 71 is given as the sum of the fluid pressures in the hole 15 that act on the
If the hydraulic pressure is low when the vehicle is lightly loaded and the deceleration reaches a predetermined value, it will be a high value, and if the vehicle is fully loaded and the hydraulic pressure is high when the deceleration reaches the predetermined value. , a relatively low value.

Therefore, when the vehicle is lightly loaded and does not require a large braking force for the rear wheel brakes, the bypass valve 71 operates to reduce the possibility that high brake fluid pressure is suddenly supplied, and the vehicle When the rear wheels are in a fully loaded state or close to it and require greater braking force to the rear wheels, the bypass valve γ can be easily activated by strongly depressing the brake pedal 2.
1 to supply higher brake fluid pressure to the rear wheels.

As is clear from the above explanation, the present invention provides a bypass valve that bypasses the deceleration response valve that operates in response to a predetermined deceleration of the vehicle, and this bypass valve is connected to the hydraulic pressure in the inlet chamber and the hydraulic pressure in the control chamber. By opening the valve when the sum of the pressing forces from the valve springs exceeds the urging force of the valve spring, the control When the hydraulic pressure in the control chamber is low, the hydraulic pressure in the inlet chamber that acts to open the bypass valve is set to a high value, and when the hydraulic pressure in the control chamber is high, the hydraulic pressure in the inlet chamber that acts to open the bypass valve is set to a high value. The fluid pressure in the chamber can be set to a low value.

Therefore, when the vehicle is lightly loaded and a large braking force is not required for the rear wheel brakes, the bypass valve opens to reduce the possibility that brake fluid pressure from the master cylinder is supplied to the control chamber. , it can reduce the possibility of sudden high brake fluid pressure being supplied to the rear wheel brakes, and when the vehicle is fully loaded or close to it, the bypass valve is installed. Easily open the valve and apply brake fluid pressure from the master cylinder directly to the control piston.

Higher brake fluid pressure can be quickly supplied to the rear wheel brakes.

A bypass valve is installed between the inlet chamber and the control chamber, so even if the bypass valve is activated, brake fluid pressure controlled by a stepped piston can be supplied to the rear brakes. It has the effect of

Note that the present invention is not limited to the above-described embodiments, but may be applied to a type in which the biasing force of the preload spring that biases the stepped piston increases in accordance with the brake fluid pressure specified by the deceleration responsive valve. For hydraulic control valves, the shape of the stepped piston,
It is clear that implementation is possible regardless of whether the stepped piston and the control piston are arranged in the same cylinder bore.

[Brief explanation of drawings]

The figure is a drawing showing a brake system including a sectional view of a deceleration responsive hydraulic pressure control valve showing an embodiment of the present invention. 1...Mendem master cylinder, 5,5'.
...Front wheel brake device, 7... Deceleration response hydraulic pressure control valve, 11, 11'... Rear wheel brake device, 12... Body, 13. I4...
...Cylinder hole, 18...Stepped piston, 19
...... Control piston, 21°22... Valve means, 24... Outlet chamber, 27-... Inlet chamber, 33... Control chamber , 36...Air chamber, 39...Preload spring, 50.53...
・Deceleration responsive valve, 60... Bypass valve member, 6
0a... Stepped portion (second pressure receiving surface) 60b...
・Right end surface (first pressure receiving surface), 64... Spring, T1
...Bypass valve.

Claims (1)

[Scope of utility model registration request] A stepped piston with a small pressure receiving surface that receives hydraulic pressure in an inlet chamber connected to a master cylinder and a large pressure receiving surface that receives hydraulic pressure in an outlet chamber connected to a rear wheel brake facing each other, and this stepped piston. valve means that opens and closes the liquid passage between the inlet chamber and the outlet chamber by movement due to a pressure difference between hydraulic pressures acting on both pressure receiving surfaces of the stepped piston, and a valve means that moves the stepped piston in a direction in which the valve means opens. a preload spring that presses; a control chamber that is connected to the inlet chamber via a deceleration responsive valve that closes in response to vehicle deceleration; A deceleration-responsive hydraulic control valve comprising a control piston that increases the biasing force of the preload spring in accordance with the pressure, the deceleration-responsive valve is bypassed and the inlet chamber and the front B are connected to each other.
A liquid passage is provided that directly connects the +J chamber, and this liquid passage is provided with a first pressure receiving surface that receives the liquid pressure of the inlet chamber and a second pressure receiving surface that receives the liquid pressure of the control chamber, and the first pressure receiving surface and the second pressure receiving surface that receive the liquid pressure of the control chamber. Second
A deceleration-responsive hydraulic pressure control valve characterized by interposing a bypass valve that opens when the sum of the pressing forces of each hydraulic pressure acting on a pressure-receiving surface exceeds the biasing force of a valve spring.