JP3175443B2 - Vehicle brake pressure reducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pressure reducing valve device for a vehicle.

[0002]

2. Description of the Related Art A hydraulic control device is interposed between a brake pedal and a master cylinder, or in the middle of a pipe connecting the master cylinder and each of the front and rear left and right wheel cylinders. There is a brake pressure control device that drives to control a braking force (brake pressure) that acts on each wheel to improve steering performance.

FIG. 7 shows an example of a conventional brake pressure control device. The master cylinder 5 supplies hydraulic pressure to the wheel cylinders 1 and 3 of the right and left front wheels FWR and RWR, and the left and right front and rear wheels FWL and RWL. An actuator, for example, a double-acting hydraulic cylinder 8, 9 is inserted between each rod of the master cylinder 6 for supplying oil pressure to the wheel cylinders 2, 4 and the brake pedal 7, and these cylinders 8 and 9 are reverse-parallel-connected. And the control pressure Pa or Pb is supplied to one of the cylinders 8.

At the time of normal braking, when the brake pedal 7 is depressed, the hydraulic cylinders 8 and 9 are evenly pushed, and the master cylinders 5 and 6 are driven to drive the wheel cylinders 1 and 2.
Supply hydraulic pressure to 3, 2 and 4 and right and left front wheels FWR, RW
R, to generate a braking force evenly on the front left and right wheels RWL, RWL. For turning braking, for example, for left turning braking, the cylinder 8
Is supplied to the cylinder, the piston of the cylinder 8 moves to the left according to the control pressure Pa, the master cylinder 5 is driven in the pressurizing direction, and the hydraulic pressure of the wheel cylinders 1 and 3 is increased to the right. The braking force of the wheel increases. On the other hand, the piston of the cylinder 9 moves to the right, the master cylinder 6 is driven in the pressure reducing direction, the hydraulic pressure of the wheel cylinders 2, 4 is reduced, and the braking force of the left wheel is reduced. That is, during turning braking, the braking force of the outer wheel is increased, and the braking force of the inner wheel is reduced.

As shown in FIG. 8 of Japanese Patent Application Laid-Open No. 2-185847, a valve 11 is inserted into a brake fluid passage 10 that connects a master cylinder 15 and a wheel cylinder 1, and the valve 11 is opened and closed. Control cylinder 12
And a control chamber 12a to which the hydraulic pressure from the accumulator 14 is applied is provided on one side of the piston, and a variable fluid chamber 12b is provided on the other side of the brake fluid passage 10, so that the hydraulic pressure in the control chamber 12a decreases. When the valve 11 is closed, the volume of the variable liquid chamber 12b is increased and the liquid chamber 13b of the cylinder 13 is increased.
A pressure control valve that absorbs the pressure fluid of the wheel cylinder 1 through the pressure control valve is disclosed.

[0006]

However, the brake pressure control device having the structure shown in FIG. 7 has a large shape and the master cylinders 5, 6 and the cylinders 8, 9 and the brake pedal 7 are connected by a link. Due to the structure, the mounting position is limited, and there is a problem that the degree of freedom in layout is small. The pressure control valve shown in FIG. 8 requires another valve (valve device) 11 in addition to the control cylinder 12 in order to cut off the fluid path 10 that connects the master cylinder 15 and the wheel cylinder 1 side. Becomes complicated. In addition, in a state where the fluid passage 10 between the master cylinder 15 side and the wheel cylinder 1 side is shut off, there is a problem that the wheel cylinder pressure cannot be increased even if the master cylinder pressure increases due to an increase in the depression of the brake pedal 7. .

The present invention has been made in view of the above points, and has as its object to provide a brake pressure reducing valve device which is small, light, and simple in structure.

[0008]

Means for Solving the Problems] According to the present invention in order to achieve the above object, a pilot cylinder fluid pressure adjusting cylinders and pilot pressure to be connected to the master cylinder and the wheel cylinders is introduced adjacent A control housed in the provided hydraulic pressure adjusting cylinder, the hydraulic pressure adjusting cylinder being divided into a master cylinder side chamber and a wheel cylinder side chamber adjacent to the pilot cylinder, and having a communication passage communicating the two chambers. A first spring for biasing the control piston to an initial position where the volume of the wheel cylinder side chamber is minimized;
Housed in the pilot cylinder, a valve unit capable of interrupting the communication passage of the control piston with partitioning the pilot cylinder and the pilot pressure introducing chamber and the low pressure chamber to which the pilot pressure is introduced, the pilot pressure introduced Room
Side receives the pilot pressure and changes to the control piston side.
A pressure receiving piston that displaces the control piston at least against the urging force of the first spring in a state where the communication path is shut off by the valve portion, and a valve receiving portion in a state where the pilot pressure is minimized. A second spring for urging the pressure receiving piston in a direction opposite to the pilot pressure so as to release the interruption of the communication path, and a second spring provided in parallel with the communication path on the control piston and the control piston being at an initial position. The master cylinder side chamber and the wheel cylinder side chamber communicate with each other, and a communication control valve that shuts off the flow from the master cylinder side chamber to the wheel cylinder side chamber when the control piston moves a predetermined amount from the initial position. Things.

[0009]

When the pilot pressure (control pressure) is not applied, the control piston is moved to the initial position by the spring force of the first spring, the communication passage for communicating the wheel cylinder side chamber and the master cylinder side chamber is opened, and the brake is braked. The system is normally braked. When pilot pressure is applied,
The pressure receiving piston moves against the spring force of the second spring, moves the control piston from the initial position, and the valve section blocks the communication passage of the control piston. At the same time, the communication control valve shuts off the flow of the hydraulic fluid from the master cylinder side chamber of the control piston to the wheel cylinder side chamber. With the movement of the control piston, the volume of the wheel cylinder side chamber of the hydraulic pressure adjustment cylinder increases, and the wheel cylinder pressure decreases.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a brake system of a vehicle to which a brake pressure reducing valve device according to the present invention is applied, in which a master cylinder 15 and wheel cylinders 1 of front, rear, left and right wheels are shown.
Between the pressure control valve (hereinafter simply referred to as “control valve”) 20 and the pressure reduction control valve (hereinafter simply referred to as “control valve”) 4
0 is inserted, the control valve 20 pressurizes and controls the brake pressure supplied to the front wheel cylinders 1 and 2, and the control valve 40 controls the brake pressure supplied to the rear wheel cylinders 3 and 4. Control pressure reduction. Control pressures (pilot pressures) Pa and Pb are supplied to these control valves 20 and 40, respectively. The control valve 20 performs a pressurizing operation in accordance with the control pressure Pa or Pb. 40 is the control pressure Pa or Pb
A pressure reducing action is performed according to.

The control valve 20 pressurizes the brake pressure of the wheel cylinder 1 on the right side of the front wheel (hereinafter simply referred to as "control valve") 20R, and pressurizes the brake pressure of the wheel cylinder 2 on the left side. A pressurization control valve (hereinafter simply referred to as a “control valve”) 20L to be controlled is integrally housed in the casing 21 in parallel. The control valve 40 is a pressure reducing control valve (hereinafter simply referred to as a “control valve”) 40R that controls the pressure of the brake of the wheel cylinder 3 on the right side of the rear wheel.
And a pressure reducing control valve (hereinafter simply referred to as “control valve”) 40L for controlling the pressure reduction of the brake pressure of the left wheel cylinder 4 are integrally housed in parallel in the casing 41.

As shown in FIG. 2, the control valve 40 includes a hydraulic pressure adjusting cylinder 41a, a hole 41b, and a pilot cylinder 41c on one side of a casing 41, and a hydraulic pressure adjusting cylinder 4 on the other side.
1d, a hole 41e, and a pilot cylinder 41f are formed so as to communicate linearly with each other along the axial direction. The holes 41b and 41e communicating the cylinders 41a and 41c and the cylinders 41d and 41f are smaller in diameter than the cylinders 41a and 41d. Ports 41g and 41 that open at both ends of the cylinder 41a are provided on one side wall of the casing 41.
h, a small hole 41i opening on the partition wall side with respect to the hole 41b of the cylinder 41c, and a port 41j opening at the center of the rear end of the cylinder 41c are provided on the rear end surface. The small holes 41i are holes for venting air. A port 41k which similarly opens on the cylinder 41d on the other side wall of the casing 41,
41m, a small hole 41n opening to the cylinder 41f, and a port 41p are provided.

A control piston 42 and a pressure receiving piston 43 are housed in the cylinders 41a and 41c, respectively. The piston 42 connects the cylinder 41a to the front end side chamber (master cylinder).
Rear chamber) and the rear end side adjacent to the pilot cylinder 41c.
Chamber (wheel cylinder side chamber)
A hole (communication passage) 42a for communicating these two chambers is provided through the center, and a flange 42b is provided concentrically around the entire periphery in the vicinity of the peripheral edge of the rear end face.
Is provided with a plurality of holes 42c in the radial direction. The outer diameter of the flange 42b is slightly smaller than the outer diameter of the piston 42. In the illustrated state where the flange 42b of the piston 42 is in contact with the partition wall with the hole 41b, a gap is provided between the rear end surface of the piston 42 and the partition wall, and the partition side chamber of the cylinder 41a communicates with the port 41h. ing.

A hole 42d is formed in the piston 42 in the axial direction in parallel with the hole 42a of the axial center.
A check valve 44 is housed in d. This check valve 44
Allows the flow of hydraulic oil only from the rear end side chamber of the piston 42 to the front end side chamber. The rear end face of the cylinder 41a, that is, the hole 4
A base end of a rod 45 is axially implanted on the end face of the partition wall 1b, and its tip is loosely fitted into a hole 42d of the piston 42 to open and close the check valve 44 with the movement of the piston 42. It has become. That is, the check valve 44 is
The second flange 42b is pushed by the rod 45 in the illustrated state in contact with the partition to open the valve, and the piston 42 is separated from the rod 45 and closed as the piston 42 separates from the partition. Thus, the state in which the flange 42b is in contact with the partition wall
That is, when the piston 42 is in the initial position,
The front end chamber communicates with the rear end chamber, and the piston 42 is in the initial position.
From the front end side chamber to the rear end side chamber
The hole 42d, the check valve 44 and the rod 4
5, a communication control valve is formed.

The piston 43 includes a pilot cylinder 41
c through a port 41j to which a control pressure is introduced.
Low pressure communicating with the atmosphere through the pressure introduction chamber and the small hole 41i.
A shaft 43a is integrally formed on the front end face, and the shaft 43a is slidably fitted into the hole 41b via an O-ring, and has a conical valve end. Thus, the piston 42 can be closed by contacting the opening end of the hole 42a of the piston 42. The shaft 43a has a hole 41 in the illustrated state where the piston 43 is in contact with the rear end face of the cylinder 41c.
b slightly protrudes into the cylinder 41a and the piston 42
Opposes the opening end of the hole 42a at a slight gap.
2a communicates with the port 41h. Piston 42
(First spring) 46 is provided between the front end surface of the piston 41 and the inner surface of the front end of the cylinder 41a.
A spring (second spring ) is provided between the front end face of the
G) 48 are contracted. Thus, the control valve 40R on one side is configured.

The control valve 40L on the other side has exactly the same configuration as the control valve 40R. Note that the control valve 40L is
Members corresponding to 0R are denoted by reference numerals in their fifties, and detailed description is omitted. Returning to FIG. 1, each of the front control valves 20R, 2R
0L ports 21g and 21k are front wheels FWR and FWL, respectively.
Ports 41h, 41m of the control valves 40R, 40L on the rear side are connected to the rear wheels RW, respectively.
R, RWL are connected to the wheel cylinders 3, 4. The port 21h of the control valve 20R and the port 41k of the control valve 40L are connected to the port 2 of the control valve 20L by the oil passage 60.
1 m and a port 41g of the control valve 40R are connected by an oil passage 61. Further, the port 21j of the control valve 20R and the port 41p of the control valve 40L are connected by the oil passage 62 to the control valve 2R.
The port 21p of 0L and the port 41j of the control valve 40R are connected by an oil passage 63.

The oil chambers before and after the tandem type master cylinder 15 are connected in the middle of the oil passages 60 and 61, respectively.
Oil passages 64, 65 are connected to 63, and oil passages 64, 65 are connected.
65 is supplied with control pressures Pa and Pb. The master cylinder 15 is connected to the brake pedal 7 via a booster 16. The control pressures Pa and Pb are supplied from a hydraulic control device 70 including a pressure control valve, a direction switching valve, and the like. And the pressurization control valve 20 and the pressure reduction control valve 40
It is controlled by two control pressures. In this way, the master cylinder 15 and the front, rear, left and right wheel cylinders 1 to 4 are connected to the X-shaped pipe via the control valves 20 and 40 to form a brake system.

The control valves 20 and 40 completely separate the liquid chamber and the oil path to which the control pressures Pa and Pb are applied, and the liquid chamber and the oil path connecting the master cylinder 15 and each of the wheel cylinders 1 to 4. Therefore, it is possible to use a control hydraulic oil other than the brake fluid as the hydraulic oil for the control pressures Pa and Pb. The operation will be described below with reference to FIGS. In order to simplify the explanation, the right control valve 4
A case in which the right rear wheel RWR is braked by 0R will be described.

In FIG. 3, the control valve 40R is in the position shown by the dotted line when the brake pedal 7 is released when the brake pedal 7 is released, and when the control pressure Pb is 0, the piston 43 is moved to the right end by the spring force of the spring 48. When pushed, the piston 42 is pushed to the right end by the spring force of the spring 46, and the end face of the flange 42b is in contact with the partition. And
The opening end of the hole 42 a of the piston 42 is opened apart from the valve portion at the tip of the shaft 43 a of the piston 43. The check valve 44 is opened by being pushed by the rod 45.

In this state, when the brake pedal 7 is depressed as shown by a solid line, hydraulic pressure is discharged from the master cylinder 15, and the port 41g, the master cylinder side chamber of the cylinder 41a, the holes 42a and 42c of the piston 42, and the wheel of the cylinder 41a It is supplied to the wheel cylinder 3 as shown by the arrow through the cylinder side chamber and the oil passage of the port 41h, and a braking force is applied to the rear wheel RWR. Since the master cylinder 15 and the wheel cylinder 3 are communicated with each other by the oil passage, the master cylinder pressure and the wheel cylinder pressure become equal. This braking is normal braking, and the pistons 42 and 43 are immobile.

When the control pressure Pb is supplied from the hydraulic control device 70 (FIG. 1) in the normal braking state shown in FIG. 3, the piston 43 is pushed to the left against the spring force of the spring 48 as shown in FIG. And the valve at the end of the shaft 43a is
And the piston 4 is closed.
2 is pushed leftward against the spring force of the spring 46.
At this time, the air in the low pressure chamber of the cylinder 41c is
Is discharged from When the piston 42 is pushed to the left, the check valve 44 is separated from the rod 45 and closed, and the hole 42d is closed.
Is closed. As a result, the oil passage between the master cylinder 15 side and the wheel cylinder 3 side is shut off. Piston 42
Is pushed leftward by the piston 43 according to the control pressure Pb, the volume of the wheel cylinder side chamber of the cylinder 41a increases, and the wheel cylinder pressure is reduced.
That is, pressure reduction of the rear wheel RWR is controlled according to the control pressure Pb.

When the brake pedal 7 is further depressed to increase the hydraulic pressure of the master cylinder 15 from the state in which the control pressure Pb shown in FIG. 4 is applied and the wheel cylinder 3 is depressurized, the piston 42 is moved as shown in FIG. Pushed to the right against the pressing force of the piston 43, the check valve 44 is opened, and the hydraulic pressure from the master cylinder 15 is supplied to the wheel cylinder 3 through the check valve 44 through a path as indicated by an arrow.
Wheel cylinder pressure increases. The check valve 44 closes when the master cylinder pressure and the wheel cylinder pressure have a pressure difference corresponding to the control pressure Pb, and keeps the pressure difference constant. Therefore, if the control pressure Pb is constant, the pressure difference between the master cylinder pressure and the wheel cylinder pressure is kept constant regardless of the magnitude of the master cylinder pressure.

When the control pressure Pb decreases to 0 from the pressure-increasing state caused by increasing the depression of the brake pedal shown in FIG.
The piston 42 moves to the right end by the spring force of the spring 46, as shown in FIG.
2a is opened to allow communication between the master cylinder 15 side and the wheel cylinder 3 side. As a result, the master cylinder pressure becomes equal to the wheel cylinder pressure, and the braking force of the rear wheel RWR becomes a normal braking force.

The left control valve 40L is also the right control valve 4
It operates in the same manner as 0R to reduce the braking force on the left rear wheel RWL in accordance with the control pressure Pa supplied from the hydraulic control device 70 (FIG. 1).

[0025]

As described above, according to the present invention, a brake pressure reducing valve device having a simple structure, small size, light weight, and low cost can be provided. In addition, during normal braking, the control piston and the pressure receiving piston are inoperative, so that deterioration of the seal and the influence of friction are reduced, and the life of the seal is prolonged. It also has excellent effects such as being economical.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a brake system equipped with a vehicle brake pressure reducing valve device according to the present invention.

FIG. 2 is an enlarged view of the pressure reducing control valve 40 of FIG.

FIG. 3 is a diagram showing the operation of the control valve 40R of FIG. 1 during normal braking.

FIG. 4 is a diagram showing an operation of the control valve 40R in FIG. 3 during pressure reduction control.

FIG. 5 is a diagram showing the operation of the control valve 40R of FIG. 4 when the master cylinder pressure is increased.

FIG. 6 is a diagram showing the operation of the control valve 40R of FIG. 5 when the control pressure is reduced.

FIG. 7 is a brake system diagram of a vehicle equipped with a conventional brake pressure control device.

FIG. 8 is a brake system diagram of a vehicle equipped with a conventional brake pressure control valve.

[Explanation of symbols]

 1-4 wheel cylinder 7 brake pedal 15 master cylinder 16 booster 20, 20R, 20L pressure control valve 40, 40R, 40L pressure reduction control valve 21, 41 casing 42, 52 control piston 43, 53 pressure receiving piston 44, 54 reverse Stop valve 70 Hydraulic control device FWR, FWL, RWR, RWL Wheel Pa, Pb Control pressure (pilot pressure)

Claims (1)

(57) [Claims] 1. A a casing and a pilot cylinder is provided adjacent the hydraulic adjusting cylinder and the pilot pressure connected to the master cylinder and the wheel cylinders is introduced, it is accommodated in the hydraulic pressure adjusting cylinder, the liquid A control piston that divides the pressure adjusting cylinder into a master cylinder side chamber and a wheel cylinder side chamber adjacent to the pilot cylinder and has a communication passage communicating between the two chambers; A first spring biased to an initial position, housed in the pilot cylinder, partitioning the pilot cylinder into a pilot pressure introduction chamber and a low pressure chamber into which the pilot pressure is introduced, and can shut off a communication passage of the control piston. The pilot pressure introduction chamber
Side receives the pilot pressure and changes to the control piston side.
A pressure receiving piston which displaces against the urging force of at least the first spring of the control piston while blocking the communicating path by the pre Kiben unit and position, the valve portion in a state in which the pilot pressure is minimum A second spring that urges the pressure receiving piston in a direction opposite to the pilot pressure so as to release the interruption of the communication passage by the control piston; and the control piston is provided in parallel with the communication passage and the control piston is at an initial position. A communication control valve that communicates the master cylinder side chamber with the wheel cylinder side chamber, and shuts off the flow from the master cylinder side chamber to the wheel cylinder side chamber when the control piston moves a predetermined amount from the initial position. Brake pressure reducing device for a vehicle.