JPH0826094A - Hydraulic valve - Google Patents

Abstract

PURPOSE:To provide a hydraulic valve which possesses the large degree of freedom in the setting of the hydraulic pressure characteristic, secures the easy brake distribution control and possesses the high performance and the small stroke. CONSTITUTION:When the hydraulic pressure becomes larger than the sum of the pressure in an oil chamber D and the urging force of a spring 14, a piston 3 shifts rightward, and valves 8 and 13 are closed. When the hydraulic pressure increases, the piston 3 shifts leftward, and the hydraulic pressure flows into an oil chanber C, and the hydraulic pressure is adjusted. When the hydraulic pressure increases furthermore, and the pistin 3 deflects, a piston 2 is shifted rightward by the master cylinder pressure acting into the oil chamber A, and each hydraulic pressure in the oil chambers B and C is increased in accordance with the sectional area ratio of the piston 2. and the piston 3 is shifted rightward, and the hydraulic pressure in the oil chamber D is increased according to the sectional area ratio of the piston 2. Furthr, when the higher prescribed hydraulic pressure is reached, the piston 2 shifts further rightward, and the hydraulic pressure acts into the oil chamber C, and the piston 3 shifts leftward, and the higher hydraulic pressure acts into the oil chamber D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control valve, and more particularly to a hydraulic booster for boosting the hydraulic pressure supplied from a hydraulic source, a control valve for controlling a brake of a vehicle, and the like. The present invention relates to a simple and inexpensive hydraulic control valve that can be applied to any of the above and can easily change the control characteristics.

[0002]

2. Description of the Related Art Conventionally, for example, as a hydraulic control valve used for boosting an operating force in a hydraulic brake device of an automobile, Japanese Patent Publication No. 34-1008.
The ones shown in the issue are well known. The structure of this hydraulic control valve will be described with reference to the drawings. In FIG. 4, 51 is a two-stage piston slidably provided in a hydraulic cylinder 52 and having different cross-sectional areas. The inside of the hydraulic cylinder is partitioned by 51 into a wide sectional area chamber 53 and a narrow sectional area chamber 54. The two-stage piston 51 is urged to the left in the figure by a return spring 55, and a flow hole 56 is formed in the center of the two-stage piston 51. The middle portion of the flow hole 56 is pressed against the wide sectional area chamber 53, and when the two-stage piston 51 moves in the hydraulic cylinder 52 to the left in the drawing, the stopper 57 forces the flow passage. The valve 58 that opens the door is stored.

Therefore, according to the hydraulic control valve having the above structure, for example, immediately after the brake pedal is depressed, the hydraulic pressure generated in the master cylinder (not shown) is caused by the action of the wide sectional area chamber 53 in the hydraulic cylinder → the stopper. The open valve 58 → acts on the wheel cylinder connected to the tip of the hydraulic control valve through the narrow sectional area chamber 54, and the brake works. However, the large cross-section area 5
When the hydraulic pressure of 3 further increases, the two-stage piston moves due to the cross-sectional area ratio formed in the two-stage piston 51 and the valve 58 closes, and a high hydraulic pressure is generated in the narrow cross-sectional area chamber 54 according to the cross-sectional area ratio. Then, it comes to act on the brake cylinder.
In this way, the hydraulic control valve can obtain a strong braking force without increasing the stroke of the brake pedal. This control valve can be used not only as a normal hydraulic booster, but also as a so-called proportioning valve for making a difference in brake pressure between front wheels and rear wheels in an automobile.

However, in the hydraulic control valve described in the above-mentioned conventional example, when the hydraulic pressure generated in the master cylinder becomes equal to or higher than a predetermined pressure, as shown by the dotted line C in FIG. Since the hydraulic pressure on the W / C side is boosted according to the area ratio, the degree of freedom in setting the brake hydraulic pressure characteristics is low, and it is necessary to perform detailed brake hydraulic pressure control depending on the running condition. In automobiles, the performance as a hydraulic control valve is insufficient.

[0005]

SUMMARY OF THE INVENTION Therefore, according to the present invention, by combining two pistons each having a large and small cross-sectional area and a valve which is actuated by hydraulic pressure, the degree of freedom in setting hydraulic characteristics is large, and the brake distribution control is performed. It is an object of the present invention to solve the above problems by proposing a small-sized and high-performance hydraulic control valve that is easy to perform and has a small stroke of the valve body.

[0006]

Therefore, the first technical solution adopted by the present invention has a first stepped piston 2 and a second stepped piston 3 which are slidable in the cylinder body 1. Then, a first oil chamber A communicating with a hydraulic pressure source is provided between the large cross-sectional area side of the first stepped piston 2 and the cylinder body, and is provided between the first stepped piston 2 and the second stepped piston 3. The second oil chamber B and the third oil chamber C are respectively formed with a fourth oil chamber D communicating with the actuator between the small cross-sectional area side of the second stepped piston 3 and the cylinder body 1, and each of the stepped portions is formed. The piston includes passages 7 and 11 formed therein, and a first valve 8 and a second valve 13 arranged in each passage and operated by hydraulic pressure,
When the oil pressure from the oil pressure source is below a predetermined value, the oil pressures of the oil pressure source and the fourth oil chamber D are substantially equal, and when the oil pressure from the oil pressure source exceeds a predetermined value within a certain range, the first stage When the second staged piston 3 is actuated by the hydraulic pressure regulated by the auxiliary piston 2 to boost the hydraulic pressure in the fourth oil chamber D, and when the hydraulic pressure exceeds the above range, the hydraulic pressure from the hydraulic source is increased. Is configured so as to boost the hydraulic pressure in the fourth oil chamber only by the second stepped piston 3.

The second technical solution means has a first stepped piston 2 and a second stepped piston 3 slidably accommodated in the first stepped piston 2. A first oil chamber A communicating with a hydraulic pressure source is provided between the large cross-sectional area side of the first stepped piston 2 and the second stepped piston 3, and the first stepped piston 2
The oil chamber B between the small cross-sectional area side of the
An oil chamber C communicating with the oil chamber B is provided between the large cross-sectional area side of the second stepped piston 3 and the cylinder body 1 between the small cross-sectional area side of the second stepped piston 3 and the cylinder body 1. A fourth oil chamber D communicating with the actuator is formed, and each of the stepped pistons has passages 7 and 11 formed therein, and a first valve 8 and a first valve 8 arranged in each passage and operated by hydraulic pressure. 2 valve 13 is provided, and when the hydraulic pressure from the hydraulic source is below a predetermined value,
When the hydraulic pressures of the hydraulic pressure source and the fourth oil chamber D are substantially equal to each other and the hydraulic pressure from the hydraulic pressure source exceeds a predetermined value within a certain range, the hydraulic pressure adjusted by the first stepped piston 2 causes the second stage. When the hydraulic pressure in the fourth oil chamber D is boosted by operating the attached piston, and when the hydraulic pressure exceeds the range, the hydraulic pressure in the fourth oil chamber is boosted only by the second stepped piston 3. It is characterized by being configured as appropriate.

[0008]

[Operation] When the brake pedal is depressed and the hydraulic pressure generated in the master cylinder is in an initial state where the hydraulic pressure is extremely low, the first oil chamber A → the first valve 8 → the second oil chamber B → the third oil chamber C → Second valve 13
Acting on the fourth oil chamber D through the bypass oil passage 17
It acts on the fourth oil chamber D through the check valve 15 provided in the. The hydraulic pressure acting on the second oil chamber B and the third oil chamber C increases,
The force to move the second stepped piston 3 to the right is
When the sum of the hydraulic pressure acting on the fourth oil chamber D and the urging force of the second spring 14 becomes larger, the second stepped piston 3 moves to the right in the figure until these forces are balanced. As a result,
Since the first valve 8 is closed by the urging force of the spring 8c and the second valve 13 is closed by the urging force of the spring 13c, the second oil chamber B and the third oil chamber C are shut off from the master cylinder side. In this state, the master cylinder pressure is also acting on the first oil chamber A, but since the hydraulic pressure is still low, the urging force of the first spring 6 keeps the first stepped piston 2 in the state shown in FIG. ing. When the hydraulic pressure of the master cylinder increases and the hydraulic pressure of the fourth oil chamber D increases via the check valve 15, the second stepped piston moves leftward in the figure by this hydraulic pressure, and the second valve 13 moves to the second engagement position. The hydraulic pressure of the fourth oil chamber flows into the third oil chamber via the second valve 13 which is opened by the stop rod 13d. When the hydraulic pressure flows into the third oil chamber C, the second stepped piston 3 moves rightward in the drawing due to the sectional area ratio, and the hydraulic pressure in the fourth oil chamber increases again. Thus, the third oil chamber C
And the hydraulic pressure of the fourth oil chamber D are regulated. Through the above process, the relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder increases at a ratio of 1: 1 until the master cylinder rises to a predetermined hydraulic pressure, as shown by a in FIG. To do.

Next, when the hydraulic pressure of the master cylinder further increases and the second stepped piston is biased to a predetermined position, this time, the first stepped piston 2 is moved to the right by the master cylinder pressure acting on the first oil chamber A. And the hydraulic pressure in the second oil chamber B and the third oil chamber C is increased according to the cross-sectional area ratio of the first stepped piston 2. At this time, the first valve 8 is closed. And
Due to the increased oil pressure in the second oil chamber B and the third oil chamber C,
The second stepped piston moves to the right in the figure, and increases the hydraulic pressure in the fourth chamber according to the sectional area ratio of the first stepped piston. At this time, the check valve provided in the bypass is also closed by the hydraulic pressure generated in the fourth oil chamber that is higher than that of the master cylinder. As a result, the hydraulic pressures of the second oil chamber B and the third oil chamber C are adjusted by the movement of the first stepped piston 2. Through the above process, the relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder increases at a predetermined inclination. This inclination can be freely changed by setting the first stepped piston, the first spring, the second stepped piston, and the second spring.

When the hydraulic pressure generated in the master cylinder reaches a predetermined higher hydraulic pressure, the increased hydraulic pressure causes the first stepped piston 2 to move further rightward and come into contact with the stopper 5. At this time, the first valve 8 is kept open by the first locking rod 8d, and the high hydraulic pressure from the master cylinder directly acts on the third oil chamber C via the second oil chamber B. Due to this oil pressure, the second stepped piston moves to the left this time, and a much higher oil pressure corresponding to the cross-sectional area ratio of the second stepped piston is generated in the fourth oil chamber. As a result, thereafter, as the hydraulic pressure of the master cylinder increases, the hydraulic pressure of the wheel cylinder increases at a predetermined inclination corresponding to the cross-sectional area ratio of the second stepped piston. Note that this inclination can be freely changed by setting the cross-sectional area ratio of the second step piston as in the conventional oil chamber control valve described above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a hydraulic control valve according to the first embodiment of the present invention. As shown in FIG. 1, a hydraulic control valve 10 according to a first embodiment includes a cylinder body 1 and a first stepped piston 2 having a large and small cross-sectional areas which are slidably accommodated in series in the axial direction of the cylinder. , And the second stepped piston 3. First stepped piston 2
Is arranged so that the large cross-section side is directed toward the oil passage 4 side communicating with the M / C, and the first stepped piston 2 is biased leftward in the figure by the first spring 6, and The stepped piston 2 is prohibited from moving to the right in the figure by a stopper 5 provided on the cylinder body 1 for a predetermined stroke or more. A first flow path 7 is formed in the first stepped piston 2, and a first valve 8 is arranged in this flow path 7.
The first valve 8 includes a valve seat 8a formed in the first flow path 7,
A valve body (ball) 8b that abuts the valve seat 8a, and the valve body 8
a spring 8c for urging b toward the valve seat 8a, and a first member arranged in the first flow path 7 and for separating the valve body 8b from the valve seat against the urging force of the spring 8c. It is composed of a stop rod 8d. The spring 8c is supported by a stop ring (not shown) provided on the main body of the first stepped piston 2,
When the valve 8 is not operated, the first flow path 7 is open as shown in the figure.

The second stepped piston 3 is constructed as a piston which is slightly larger than the first stepped piston 2, and the large area side of the second stepped piston 3 is the small area of the first stepped piston 2. These pistons are opposed to each other, and when not in operation, these pistons are in contact with each other via the plate 9 by the urging force of the second spring 14 described later. The second stepped piston 3 is biased leftward in the figure by a second spring 14. A second flow passage 11 is formed in the second stepped piston 3, and a second valve 13 is arranged in the flow passage 11. The second valve 13 includes a valve seat 13a formed in the second flow passage 11, a second valve body (ball) 13b that abuts on the valve seat 13a, and the valve body 13b facing the valve seat 13a. It includes a biasing spring 13c and a second locking rod 13d arranged in the second flow path 11 and for separating the valve body 13b from the valve seat 13a against the biasing force of the spring 13c. There is. The spring 13c is supported by a stop ring 13e provided on the second stepped piston. Second
The locking rod 13d is arranged between the plate 9 and the second valve body 13b, and when the valve 13 is not operated, the second flow path 11 is opened as shown in the figure.

In the hydraulic cylinder 1, a first oil chamber A is provided between the first stepped piston 2 and the large cross-sectional area side thereof, and between the first stepped piston and the second stepped piston. Second oil chamber B
Further, a fourth oil chamber D is formed between the third oil chamber C and the small cross-sectional area side of the second stepped piston. The first oil chamber A is connected to the oil passage 4 on the M / C side (hydraulic pressure source side), and the fourth oil chamber D is connected to the oil passage 16 on the W / C side (master cylinder side). And the oil passage 4 on the M / C side
The oil passage 16 on the W / C side is connected by a bypass oil passage 17 in which the check valve 15 is arranged.

The operation of the hydraulic control valve 10 having the above structure will be described. When the brake pedal is depressed and the hydraulic pressure generated in the master cylinder is in an initial state where the hydraulic pressure is extremely low, the first oil chamber A → the first flow path 7 → the first valve 8 → the second oil pressure
It acts on the fourth oil chamber D through the oil chamber B → the third oil chamber C → the second flow passage 11 → the second valve 13, and at the same time, through the check valve 15 provided in the bypass oil passage 17 to the fourth oil chamber D. To work. That is, at this time, the fourth oil chamber D is in communication with the third oil chamber B via the open second valve 13. The second oil chamber B, the third
The oil pressure acting on the oil chamber C is increased, and the force for moving the second stepped piston 3 to the right is larger than the sum of the oil pressure acting on the fourth oil chamber D and the urging force of the second spring 14. Then, the second stepped piston 3 moves to the right in the figure until these forces are balanced. As a result, the first valve 8 is closed by the biasing force of the spring 8c, and the second valve 13 is closed by the biasing force of the spring 13c, so that the second oil chamber B and the third oil chamber C are on the master cylinder side and the wheel cylinder side. Is cut off. In this state, the master cylinder pressure is also acting on the first oil chamber A, but since the hydraulic pressure is still low, the urging force of the first spring 6 keeps the first stepped piston 2 in the state shown in FIG. ing. Further, in this balanced state, the hydraulic pressures of the second oil chamber B and the third oil chamber C are lower than the hydraulic pressure of the fourth oil chamber D.

Then, the hydraulic pressure of the master cylinder rises,
When the hydraulic pressure in the fourth oil chamber D rises via the check valve 15, the hydraulic pressure moves the second stepped piston to the left in the figure, and the second valve 13 is opened and opened by the second locking rod 13d. The hydraulic pressure of the fourth oil chamber flows into the third oil chamber via the second valve 13 that is open. When the hydraulic pressure flows into the third oil chamber C, the second stepped piston 3 moves rightward in the drawing due to the sectional area ratio, and the hydraulic pressure in the fourth oil chamber increases again. In this way, the hydraulic pressure of the third oil chamber C and the hydraulic pressure of the fourth oil chamber D are adjusted. After the above process, until the master cylinder rises to the specified hydraulic pressure,
The relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder increases at a ratio of 1: 1 as indicated by a in FIG. 2 due to the pressure adjusting action of only the second stepped piston. At this time, the balance of the piston with the second step is to adjust the oil pressure in the third oil chamber C to PC.
, The cross section of the third oil chamber is Sc, and the cross section of the fourth oil chamber is S
d, master cylinder hydraulic pressure PM, second spring force f
Then, PC = (Sd.PM + f) / Sc. Further, the hydraulic pressure at the break points of A and B in the graph in FIG. 2 is Pk = C · F / (A · C−B · D).

Next, when the hydraulic pressure of the master cylinder rises further and the second stepped piston is biased to a predetermined position, this time, the first stepped piston 2 is moved to the right by the master cylinder pressure acting on the first oil chamber A. And the hydraulic pressure in the second oil chamber B and the third oil chamber C is increased according to the cross-sectional area ratio of the first stepped piston 2. At this time, the first valve 8 is closed. And
Due to the increased oil pressure in the second oil chamber B and the third oil chamber C,
The second stepped piston moves to the right in the figure, and increases the hydraulic pressure in the fourth chamber according to the sectional area ratio of the first stepped piston. At this time, the check valve provided in the bypass is also closed by the hydraulic pressure generated in the fourth oil chamber that is higher than that of the master cylinder. As a result, the hydraulic pressures of the second oil chamber B and the third oil chamber C are adjusted by the movement of the first stepped piston 2. Through the above-described process, the relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder rises at a predetermined inclination as shown by B in FIG. It should be noted that this inclination is based on the first stepped piston, the first step
It is possible to freely change the setting method of the spring, the second stepped piston, and the second spring.

At this time, the balance between the first stepped piston and the second stepped piston is such that the oil pressure in the first oil chamber A (master cylinder oil pressure) is PM, the cross-sectional area of the first oil chamber is Sa, and the first spring force. , F, the cross-sectional area of the second oil chamber is Sb, the second oil chamber B,
If the hydraulic pressure in the third oil chamber C is PC, the cross-sectional area of the third oil chamber is Sc, the second spring force is f, the cross-sectional area of the fourth oil chamber is Sd, and the hydraulic pressure of the wheel cylinder is PW, the second step is added. In the piston, PC = (Sd.PW + f) / Sc However, PW> PM In the first stepped piston, PC = (Sa.PM-F) / Sb. Further, the hydraulic pressure at the broken points of B and C in the graph in FIG. 2 is Pk = [C · F / D (AB)] − f / D.

When the hydraulic pressure generated in the master cylinder reaches a predetermined higher hydraulic pressure, the increased hydraulic pressure causes the first stepped piston 2 to move further rightward and come into contact with the stopper 5. At this time, the first valve 8 is kept open by the first locking rod 8d, and the high hydraulic pressure from the master cylinder directly acts on the third oil chamber C via the second oil chamber B. This hydraulic pressure moves the second stepped piston to the right, and a much higher hydraulic pressure is generated in the fourth oil chamber corresponding to the sectional area ratio of the second stepped piston. As a result, thereafter, as the hydraulic pressure of the master cylinder increases, the hydraulic pressure of the wheel cylinder increases at a predetermined inclination corresponding to the cross-sectional area ratio of the second stepped piston, as shown by C in FIG. Note that this inclination can be freely changed by setting the cross-sectional area ratio of the second step piston as in the conventional oil chamber control valve described above. The balance of the second stepped piston at this time is PM = (Sd.PW + f) / Sc where PW> PM.

Next, the structure of the hydraulic control valve according to the second embodiment of the present invention will be described with reference to FIG.
Similarly to the first embodiment, the second embodiment also has a first stepped piston 2 and a second stepped piston 3 having large and small cross-sectional areas. In the first embodiment, the first stepped piston and the second stepped piston are arranged in series in the cylinder body, whereas in the second embodiment, the first stepped piston is arranged as the second stepped piston. It is placed inside to make it even smaller overall. Further, in the second embodiment, since the bypass oil passage is unnecessary, the number of parts can be reduced.

In the figure, a second stepped piston 3 is slidably arranged in the cylinder body 1, and the second stepped piston 3 is biased to the left in the figure by a second spring 14. . A second flow passage 11 is formed in the second stepped piston 3, and the first stepped piston 2 and the second valve 13 are arranged in the flow passage 11.
The first stepped piston 2 is slidably arranged in the flow path 11 so that the large area side faces the small area side of the second stepped piston 3, and the stopper 5 provided in the second flow path 11 is provided. Therefore, the movement to the left in the drawing is prohibited for a predetermined stroke or more. The first stepped piston 2 is biased rightward in the figure by the first spring 6. A first flow path 7 is formed in the first stepped piston 2, and a first valve 8 having the same configuration as that of the first embodiment is arranged in the flow path 7. The first valve 8 is a first valve arranged in the first flow path 7.
It faces the locking rod 8d, and when the first stepped piston moves to the left in the figure, the first locking rod 8d can open the first flow path and the valve 8 Is configured to close the first flow path 7 when not operating, as shown in the figure.

The second valve 13 in the flow passage 11 has the same structure as that of the first embodiment, and the second locking rod 13d is disposed between the plate 9 and the first stepped piston 2. Is in contact with. An oil passage 20 is formed in the second stepped piston between the second valve 13 and the first stepped piston, and the oil passage 20 is connected to a master cylinder (hydraulic pressure) via an oil passage 4 formed in the cylinder body. Source). A first oil chamber A is provided between the large sectional area side of the first stepped piston 2 and the second stepped piston 3, and a second oil chamber A is provided between the first stepped piston and the second stepped piston. The oil chamber B is located between the cylinder body and the large cross-sectional area side of the second stepped piston.
A third oil chamber C communicating with each other is further formed with a fourth oil chamber D between the small cross-sectional area side of the second stepped piston and the cylinder body 1. The first oil chamber A is connected to the oil passage 4 on the M / C side (hydraulic power source) via the second passage 11 and the oil passage 20 formed in the second stepped piston, and the fourth oil Room D
Is connected to the oil passage 16 on the W / C side (actuator side). Further, the oil passage 4 on the M / C side and the oil passage 16 on the W / C side are communicated with each other through a second valve 13 which is open when not operating.

The operation of the hydraulic control valve having the above structure will be described. When the brake pedal is depressed and the hydraulic pressure generated in the master cylinder is low,
Oil passage 4 on the M / C side → oil passage 2 formed in the second stepped piston
0 → It acts on the first oil chamber A via the second flow passage 11 formed in the second stepped piston, and acts on the fourth oil chamber D via the open second stool. The relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder increases at a ratio of 1: 1 until the master cylinder rises to a predetermined hydraulic pressure, as shown by a in FIG. Then, when the hydraulic pressure of the master cylinder further increases, the first stepped piston moves to the left in the figure against the urging force of the first spring 6, and the second stepped piston
The locking rod 13d also moves to the left and the second valve 13 closes. Further, as the hydraulic pressure of the master cylinder moves the piston with the first step to the left, the hydraulic pressures of the second oil chamber B and the third oil chamber C increase according to the cross-sectional area ratio of the first step piston. At this time, the first valve 8 is closed because it has not yet moved to the position where it is pushed up by the first locking rod 8d. The second hydraulic chamber B and the third hydraulic chamber C, which have risen in pressure, cause the second hydraulic chamber B
The stepped piston moves to the right in the figure against the urging force of the second spring 14, and increases the hydraulic pressure in the fourth chamber according to the cross-sectional area ratio of the first stepped piston. In this process, the hydraulic pressures of the second oil chamber B and the third oil chamber C are adjusted by the movement of the first stepped piston 2.

As described above, the relationship between the hydraulic pressure of the master cylinder and the hydraulic pressure acting on the wheel cylinder rises at a predetermined inclination as shown by B in FIG. This inclination can be freely changed by setting the first stepped piston, the first spring, the second stepped piston, and the second spring. The balance between the first stepped piston and the second stepped piston at this time is that the oil pressure in the first oil chamber A (master cylinder oil pressure) is PM, the cross-sectional area of the first oil chamber is Sa, the first spring force is F, The cross-sectional area of the second oil chamber is Sb, the second oil chamber B,
If the hydraulic pressure in the third oil chamber C is PC, the cross-sectional area of the third oil chamber is Sc, the cross-sectional area of the fourth oil chamber is Sd, the second spring force is f, and the hydraulic pressure of the wheel cylinder is PW, the second step is applied. In the piston, PC = (Sd.PW + f) / Sc However, PW> PM In the first stepped piston, PC = (Sa.PM-F) / Sb.

When the hydraulic pressure generated in the master cylinder reaches a predetermined higher hydraulic pressure, the increased hydraulic pressure causes the first stepped piston 2 to move further leftward and the first locking rod 8d to move the first valve. 8 is forcibly opened. As a result, the high hydraulic pressure from the master cylinder directly acts on the third oil chamber C via the second oil chamber B. Due to this oil pressure, the second stepped piston moves further to the right while resisting the urging force of the second spring, and a further higher oil pressure corresponding to the sectional area ratio of the second stepped piston is provided in the fourth oil chamber. appear. After that, as the hydraulic pressure of the master cylinder increases, the hydraulic pressure of the wheel cylinder increases at a predetermined inclination corresponding to the cross-sectional area ratio of the second stepped piston, as shown by C in FIG. Note that this inclination can be freely changed by setting the cross-sectional area ratio of the second step piston as in the conventional oil chamber control valve described above. The balance of the second stepped piston at this time is PM = (Sd.PW + f) / Sc where PW> PM. In the present embodiment, the operating strokes of the first valve 8 and the second valve 13 in each piston are Sp> when the stroke of the first valve is Sp and the stroke of the second valve is Lv.
Must be Lv.

As described above, in this hydraulic control valve, the boosting state of the operating hydraulic pressure, that is, the control characteristic can be easily changed according to the hydraulic pressure of the master cylinder. Further, the entire structure of the hydraulic control valve can be downsized, and the manufacturing cost can be reduced.

[0026]

According to the present embodiment having the above-mentioned structure, by combining two pistons each having a large and small cross-sectional area and a valve which is actuated by hydraulic pressure, the degree of freedom in setting the hydraulic characteristic is increased. It is possible to obtain a large hydraulic control valve that is easy to control the brake distribution, and a small and high-performance hydraulic control valve while reducing the stroke of the valve body. Therefore, it is possible to obtain a high-performance hydraulic control valve that can be applied to current automobiles that need to perform fine brake hydraulic control according to the traveling state.

[Brief description of drawings]

FIG. 1 is a detailed view of a hydraulic control valve as a first embodiment according to the present invention.

FIG. 2 is a characteristic diagram of a hydraulic control valve.

FIG. 3 is a detailed view of a hydraulic control valve as a second embodiment according to the present invention.

FIG. 4 is a detailed view of a conventional hydraulic control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Piston with 1st step 3 Piston with 2nd step 5 Stopper 6 1st spring 7 1st flow path 8 1st valve 9 Plate 10 Hydraulic control valve 11 2nd flow path 13 2nd valve 14 2nd spring 15 Check valve A 1st oil chamber B 2nd oil chamber C 3rd oil chamber D 4th oil chamber

Claims (6)

[Claims] 1. A first stepped piston 2 slidable in a cylinder body 1 and a second stepped piston 3 are provided.
A first oil chamber A communicating with a hydraulic source is provided between the large cross-sectional area side of the stepped piston 2 and the cylinder body, and a second oil chamber B is provided between the first stepped piston 2 and the second stepped piston 3. And the third oil chamber C
The small cross-sectional area side of the second stepped piston 3 and the cylinder body 1
A fourth oil chamber D communicating with the actuator, and the stepped pistons are provided with flow passages 7 and 11 formed therein, and the stepped pistons are arranged in the flow passages and operated by hydraulic pressure. When the hydraulic pressure from the hydraulic pressure source is equal to or lower than a predetermined value, the hydraulic pressure of the hydraulic pressure source and the fourth hydraulic chamber D are substantially equal to each other, and the hydraulic pressure from the hydraulic pressure source has a predetermined value. When it is within a certain range beyond, the second stepped piston 3 is actuated by the hydraulic pressure regulated by the first stepped piston 2 to boost the hydraulic pressure in the fourth oil chamber D, and then the above range is exceeded. The hydraulic control valve is configured to boost the hydraulic pressure in the fourth oil chamber only by the second stepped piston 3 when the hydraulic pressure reaches the above hydraulic pressure. 2. The first stepped piston 2 has a first flow passage 7 formed therein, and a first valve 8 arranged in the flow passage.
And a first spring 6 for urging the first stepped piston 2 toward the first oil chamber A side, the second stepped piston 3 having a second flow passage 11 formed therein, A second valve 13 arranged in the flow path and a second spring 14 for urging the second stepped piston 3 toward the third oil chamber C are provided, and each valve is configured to be hydraulically operated. The hydraulic control valve according to claim 1, wherein: 3. A bypass oil passage 1 having a check valve 15 for the first oil chamber A and the fourth oil chamber D of the hydraulic control valve.
7. The oil chamber control valve according to claim 1, wherein the oil chamber control valve is communicated with the oil chamber. 4. A first stepped piston 2 having a first stepped piston 2 and a second stepped piston 3 slidably accommodated inside the first stepped piston 2. The first oil chamber A communicating with the hydraulic source is provided between the cross-sectional area side and the second stepped piston 3, and the oil chamber is provided between the small cross-sectional area side of the first stepped piston 2 and the second stepped piston 3. B is an oil chamber C that communicates with the oil chamber B between the large cross-sectional area side of the second stepped piston 3 and the cylinder body 1, and the small cross-sectional area side of the second stepped piston 3 and the cylinder body 1. A fourth oil chamber D communicating with the actuator is formed between the stepped pistons, and the stepped pistons are provided with flow paths 7 and 11 formed therein, and a first valve disposed in each flow path and operated by hydraulic pressure. 8 and the second valve 13, and when the oil pressure from the oil pressure source is below a predetermined value, the oil pressures of the oil pressure source and the fourth oil chamber D are substantially equal, When the hydraulic pressure from the pressure source exceeds a predetermined value within a certain range, the hydraulic pressure adjusted by the first stepped piston 2 operates the second stepped piston to double the hydraulic pressure in the fourth oil chamber D. The hydraulic control valve is configured to boost the hydraulic pressure of the fourth oil chamber only by the second stepped piston 3 when the hydraulic pressure exceeds the above range. 5. The first stepped piston 2 has a first flow path 7 formed therein, and a first valve 8 arranged in the flow path.
And a first spring 6 for urging the first stepped piston 2 toward the first oil chamber A side, the second stepped piston 3 having a second flow passage 11 formed therein, The second valve 13 arranged in the flow path 11 and the second stepped piston 3
5. The hydraulic control valve according to claim 4, further comprising a second spring 14 biased toward the oil chamber C, wherein each valve is configured to be operated by hydraulic pressure. 6. The valve stroke of the first valve 8 is the second stroke.
The hydraulic control valve according to claim 4 or 5, wherein the valve stroke is larger than the valve stroke of the valve 13.