JPH072085A - Hydraulic pressure booster - Google Patents

Abstract

PURPOSE:To simplify structure of the device and reduce the dimensions and improve the feeling in the case when a brake padal is stepped, by opening and closing the control valve of a hydraulic pressure booster indirectly by the hydraulic pressure generated in the device, independently of the operation of an operating member. CONSTITUTION:A hydraulic pressure booster is equipped with a cylinder body 1, output hydraulic pressure chamber 4 which communicates to a wheel cylinder, booster piston 3a which receives the hydraulic pressure in a power hydraulic pressure chamber 12, flow valve A which is controlled by the relative shaft between a booster piston and an action piston 13, and opens and closes the communication between the power hydraulic pressure chamber and a reservoir 2, opening/closing valve B fur cutting off the communication between the output hydraulic pressure chamber and the reservoir by the shift of the action piston, and a hydraulic pressure introducing valve C which is operated by the hydraulic pressure generated in the output hydraulic pressure chamber and permits the communication between the hydraulic pressure chamber and the power hydraulic pressure chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic booster that boosts pressure by utilizing a hydraulic pressure supplied from a hydraulic pressure source, and more particularly, a master cylinder and a hydraulic booster are integrated. The present invention relates to a small hydraulic booster.

[0002]

2. Description of the Related Art Hydraulic boosters are used, for example, in hydraulic brake systems for automobiles to boost the operating force. As disclosed in Japanese Utility Model Publication No. 3-31653, a hydraulic booster of this type generally operates in response to the operation of a power piston operated by the hydraulic pressure of a power hydraulic chamber and an operation member. An input piston and a control valve that is provided between the power piston and the input piston and that is operated by relative movement of both pistons to control the hydraulic pressure of the power hydraulic chamber are configured.

In this device, when the input piston moves forward in response to the operation of the operating member, the control valve raises the hydraulic pressure in the power hydraulic chamber, whereby the power piston moves forward and pushes the push rod of the master cylinder. Press,
The pedal force of the operator's brake pedal is reduced. At this time, the hydraulic pressure of the power hydraulic chamber is also applied to the input piston on a relatively small pressure receiving surface, and a reaction force proportional to the operating force of the power piston acts on the input piston, and the operator boosts the hydraulic pressure. It is designed to be aware of the increased output of the device.

[0004]

However, in the above hydraulic booster, a control valve for controlling the power piston is provided between the power piston and the input piston, and is operated by the relative movement of both pistons. Yes, and
Since the boosted operating force is transmitted to the push rod of the conventionally known master cylinder that is arranged in series with the power piston, the axial length of the entire device becomes long, and miniaturization is difficult. However, there is a problem in that a mounting space for that purpose is required and the manufacturing cost becomes high.

Therefore, according to the present invention, the opening and closing of the control valve (hereinafter referred to as the hydraulic pressure introducing valve) of the hydraulic booster is separated from the operation of the operation member, and indirectly by the hydraulic pressure generated in the hydraulic booster. By providing a hydraulic booster that simplifies the structure and downsizes the entire device by opening and closing, and reduces the sliding resistance when the brake pedal is pressed to improve the feel, To solve the problem.

[0006]

Therefore, the present invention provides a hydraulic booster, which comprises a cylinder body 1 and
An output hydraulic pressure chamber 4 which is arranged in the cylinder body and connects the inside of the cylinder body to a wheel cylinder, a booster piston 3a which receives the hydraulic pressure in the power hydraulic chamber 12, and a relative movement of the booster piston 3a and the action piston 13. A flow valve A controlled by a control valve for opening and closing the communication between the power hydraulic chamber 12 and the reservoir 2, an open-close valve B for disconnecting the communication between the output hydraulic chamber and the reservoir by movement of the action piston, and the output hydraulic pressure. A hydraulic pressure introducing valve C that is operated by the hydraulic pressure generated in the chamber and connects the hydraulic pressure source and the power hydraulic chamber is provided, and the flow valve A is provided slidably in the axial direction of the booster piston 3a. The action piston 13, the first flow paths 14 a and 14 b formed in the action piston 13, and the valve body 18 that opens and closes the first flow path 14. Dobentai 18 action piston 1
The first flow path 14 can be closed by the cooperation of the action piston 13 and the booster piston 3a during three operations, and this is a means for solving the problem.

[0007]

In the hydraulic booster, when the brake pedal is stepped on and the push rod 14 is pushed, the action piston 13 first moves the distance of the gap L formed by the set pin 13a and the action piston 13.
As a result, the ball valve 18 comes into contact with the valve seat 13c formed on the action piston 13, and the first passage 1
The communication between 4a and the flow path 16 is cut off. After that, when the action piston 13 contacts the set pin 13a and presses the first booster piston 3a leftward, the spring 8 is compressed, and the spring 9 moves the valve member 7 leftward and the flow path 6
Close. Then, hydraulic pressure is generated in the first output hydraulic chamber 4,
This hydraulic pressure is supplied to the wheel cylinder and moves the second booster piston 3b. As a result, the second output hydraulic chamber 5 is also shut off from the flow path 6 by the on-off valve,
A hydraulic pressure is generated in the output hydraulic chamber 5, and this hydraulic pressure is supplied to the wheel cylinder.

The hydraulic pressure generated in the first and second output hydraulic chambers 4 and 5 acts on the fail-safe piston 25 and the balance piston 26. As a result, the control valve 33 is moved to the right in the figure, and the movement of the control valve 33 causes the high pressure fluid from the accumulator to flow through the flow path 3
1a → annular groove 31b → annular groove 29 → passage 30 → passage 30
The fluid is supplied to the power hydraulic chamber 12 through the flow path 21.
The hydraulic pressure introduced into the power hydraulic chamber 12 presses the booster piston 3a to the left to reduce the pedal effort of the brake pedal of the operator. In addition, the hydraulic pressure of the power hydraulic chamber at this time acts on the action piston 13 at the portion where the action piston 13 and the ball valve 18 contact each other, whereby a reaction force proportional to the operating force of the booster piston 3a acts on the push rod. In effect, the operator may be aware of the increased output of the hydraulic booster.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a hydraulic booster according to an embodiment of the present invention. In the figure, 1 is a cylinder body, and in this cylinder body 1, first and second booster pistons 3a, 3b are arranged in series. Between the first booster piston 3a and the cylinder body 1, a power hydraulic chamber 12 having a configuration described later and a flow valve A for opening and closing a flow path to the power hydraulic chamber 12 are arranged. Also, the first
A first output hydraulic pressure chamber 4 is formed between the second booster pistons 3a and 3b, and a second output hydraulic pressure chamber 5 is further provided between the second booster piston 3b and the cylinder body. Has been formed. The first and second output hydraulic chambers 4 and 5 are communicated with the reservoir 2 via an opening / closing valve B having the same structure. Further, a hydraulic pressure introduction valve C that is indirectly opened / closed by the hydraulic pressure generated in the hydraulic pressure booster is arranged between the hydraulic booster and the accumulator AC as a hydraulic pressure source. By opening and closing the pressure introducing valve, the hydraulic pressure accumulated in the accumulator AC can be introduced into the power hydraulic chamber 12. Also, accumulator AC
A predetermined hydraulic pressure is constantly accumulated by the hydraulic pump P.

Hereinafter, the constitution of each element of the flow valve, the power hydraulic chamber, the opening / closing valve, and the hydraulic pressure introducing valve, which constitute the above hydraulic booster, will be described. [Flow Valve A and Power Hydraulic Chamber 12] In FIG. 2, an action piston 13 is slidably mounted on the booster piston 3a at the right end of the first booster piston 3a in the figure. The action piston 13 has the same circular cross section, and first flow paths 14a and 14b are formed in the piston. The first flow path 14
b is always communicated with a power hydraulic chamber 12 described later via a passage 14c. In addition, the first flow passage 14a is a valve body (here, a ball valve) 18 arranged between the booster piston 3a and the action piston 13 and the flow passage 1
A liquid chamber 15 formed by the first booster piston 3 a and the cylinder body 1 is communicated via 6. The liquid chamber 15 communicates with the reservoir 2 as shown in FIG. 1, and the ball valve 18 serves as the action piston 1.
The diameter is substantially the same as the diameter of No. 3.

The ball valve 18 is normally provided with a valve seat 13c.
And the first flow passage 14a and the flow passage 16 are communicated with each other, and when the action piston 13 moves leftward in the drawing, the action piston 13 comes into contact with the valve seat 13c and comes into contact with the first flow passage 14a and the flow passage 1.
It has a function to cut off communication with 6. An annular groove 13a is formed in the action piston 13, and a set pin 13b provided in the booster piston 3a is fitted in the annular groove 13a. A gap L is formed between the set pin 13b and the annular groove 13a to allow relative movement between the action piston 13 and the booster piston 3a, and the gap L regulates the relative movement amount between the two. ing.

The action piston 13 is a plug 20.
Is slidably fitted in the cylinder body 1, and the plug 20 is attached to the cylinder body 1 by a nut 22.
The power hydraulic chamber 12 includes a booster piston 3a and a plug 20.
And a spacer 19 is disposed in the power hydraulic chamber 12. In addition, the power hydraulic chamber 12
Is connected to a hydraulic pressure introduction valve described later by a flow path 21. In the figure, reference numeral 42 denotes a stopper, and the movement amount of the spacer 19 is regulated by the stopper 42.

Since the flow valve constructed as described above maintains the state shown in the figure when the brake is not operated,
The power hydraulic chamber 12 has a passage 14c → first passages 14a, 14
It communicates with the reservoir 2 through b → ball valve 18 → flow path 16 → liquid chamber 15 and is at atmospheric pressure. When the brake pedal is stepped on and the push rod 14 is pushed leftward in the figure, the action piston 13 first moves the distance of the gap L formed by the set pin 13a and the action piston 13. As a result, the ball valve 18 has the valve seat 1 formed on the action piston 13.
3c is contacted, and the communication between the first flow path 14a and the flow path 16 is cut off (that is, the communication between the reservoir and the power hydraulic chamber 12 is cut off).

Then, with the action piston 13 in contact with the set pin 13a, the first booster piston 3
By pressing a to the left, hydraulic pressure is generated in the first output hydraulic chamber 4 in FIG. At this time, a high-pressure hydraulic pressure from the accumulator is introduced into the power hydraulic chamber 12 from the flow path 21 via the hydraulic pressure introduction valve described later, and the booster piston 3a is pressed to the left by this hydraulic pressure, so that the operator The pedal force of the brake pedal is reduced (the so-called booster function is exerted). At this time, the hydraulic pressure of the power hydraulic chamber 12 also acts on the action piston side of the portion where the action piston 13 and the ball valve 18 contact each other, whereby a reaction force proportional to the operating force of the booster piston 3a is pushed. It acts on the rod so that the operator can be aware of the increased output of the hydraulic booster.

[Open / Close Valve B] The open / close valve is a valve for controlling the communication between the first and second output hydraulic chambers 4 and 5 and the reservoir 2. The open / close valve will be described with reference to FIGS. 1 and 3. In the following description, the on-off valve is a valve for opening and closing the communication between the flow passage 6 formed in the second booster piston 3b or the cylinder body 1 and the output hydraulic chamber 4 or the output hydraulic chamber 5. The member 7, the spring 8 that keeps the valve member 7 normally open, and the spring 8 that is operated by the push rod.
When the valve is in a compressed state, the valve member 7 is moved to move the flow path 6
It is composed of a spring 9 for shutting off. The valve member 7 is slidably provided on the washers 10 and 11.

In this on-off valve, when the push rod 14 is operated, the first booster piston 3a moves leftward in FIG. 3 and compresses the spring 8, which causes the spring 9 to move the valve member 7 leftward. It moves and closes the flow path 6 to cut off communication with the reservoir 2. Then, a hydraulic pressure is generated in the first output hydraulic chamber 4, and this hydraulic pressure is supplied to the wheel cylinder and moves the second booster piston 3b leftward in FIG. By the movement of the booster piston 3b, the on-off valve in the second output hydraulic pressure chamber 5 closes the flow path 6 in the same manner as above, and disconnects the communication between the reservoir 2 and the second output hydraulic pressure chamber 5. As a result, the second
A hydraulic pressure is also generated in the output hydraulic pressure chamber, and this hydraulic pressure is supplied to the wheel cylinder.

[Liquid Pressure Introduction Valve C] The hydraulic pressure introduction valve is a valve for introducing the hydraulic pressure accumulated in the accumulator AC shown in FIG. 1 into the power hydraulic chamber 12. As shown in FIG. 1, this hydraulic pressure introducing valve is arranged between the hydraulic booster and the accumulator, and the first and second output hydraulic chambers 4, 5 of the hydraulic booster are arranged.
It is designed to be opened and closed indirectly by the hydraulic pressure generated at. In FIG. 1, a valve body 24 is attached to the cylinder body 1.
An elongated hole 28 communicating with the first and second output hydraulic chambers 4 and 5 and the wheel cylinder is formed therein, and the elongated hole 28 communicates with the accumulator AC.
Is connected to the flow path 217 communicating with the power hydraulic chamber 12.

The fail-safe piston 2 is provided in the slot 28.
5 and a balance piston 26 are provided, the fail-safe piston 25 communicates the second output hydraulic chamber 5 with the wheel cylinder, and the first,
The communication between the second output hydraulic chambers 4 and 5 is cut off. further,
The fail-safe piston 25 is restricted from moving leftward in the drawing by a step portion 28a formed in the elongated hole 28.
The balance piston 26 communicates the first output hydraulic chamber 4 with the wheel cylinder. The fail safe 25 and the balance piston 26 are the first and second
The hydraulic pressure generated in the output hydraulic pressure chambers 4 and 5 can move to the right in the drawing.

In FIG. 4, a valve sleeve 31 is attached to the valve body 24 by a nut 34, and the control valve 3 is installed in the valve sleeve 31.
3 is slidably arranged. A spring 32 is arranged between the valve sleeve 31 and the control valve 33, and the urging force of the spring 32 causes the control valve 33 to constantly contact the balance piston 26. The valve sleeve 31 has an accumulator A
A channel 31a communicating with C is formed, and the channel 3
An annular groove 31b is formed on the inner peripheral surface of the valve sleeve 31 so as to communicate with 1a. Meanwhile, the control valve 33
A flow channel 30 is formed in the control channel 33, and the flow channel 30 communicates with an annular groove 29 formed on the outer circumference of the control valve 33. The annular grooves 31b and 29 constitute a hydraulic pressure introducing valve mechanism, and as shown in the figure, the annular groove 3b is normally provided.
Communication between 1b and 29 is broken. In addition, the flow path 3
0 communicates with the flow path 21 through the communication hole 30a.

When the push rod is pushed, the first and second
When hydraulic pressure is generated in the output hydraulic chambers 4 and 5, the fail-safe piston 25 and the balance piston 26 move the control valve 33 to the right in the figure against the biasing force of the spring 32 by this hydraulic pressure. As a result, the annular grooves 31b and 29 are communicated with each other. Then, the high-pressure hydraulic pressure from the accumulator AC changes the flow path 31a → the annular groove 31b →
It is supplied to the power hydraulic chamber 12 through the annular groove 29 → the flow passage 307 flow passage 30a → the flow passage 21 and acts on the booster piston 3a as described above. When a failure occurs in the first output hydraulic pressure chamber 4 system, the fail-safe piston 25 operates the control valve 33 via the balance piston 26 by the hydraulic pressure in the second output hydraulic pressure chamber 5 system. When the second output hydraulic pressure chamber 5 system is defective, the balance piston 26 operates the control valve 33 with the hydraulic pressure of the first output hydraulic pressure chamber 4 system. It is possible and safer.

This embodiment is constructed as described above,
It works as follows. In FIG. 1, the hydraulic booster is
Normally, the state shown in the figure is maintained, but when the brake pedal is stepped on and the push rod 14 is pushed to the left in the figure, the action piston 13 is first formed by the set pin 13a and the action piston 13. Move the distance of the gap L. Accordingly, the ball valve 18
Comes into contact with the valve seat 13c formed on the action piston 13 to cut off the communication between the first flow path 14a and the flow path 16 (that is, cut off the communication between the reservoir and the power hydraulic chamber 12). After that, when the action piston 13 comes into contact with the set pin 13a and presses the first booster piston 3a leftward, the spring 8 is compressed by the leftward movement of the first booster piston 3a, whereby the spring 9 is released. Moves the valve member 7 to the left and closes the flow path 6. Then, a hydraulic pressure is generated in the first output hydraulic chamber 4, and this hydraulic pressure is supplied to the wheel cylinder and the second booster piston 3
b is moved to the left in FIG. As a result, the second output hydraulic chamber 5 is also cut off from the flow path 6 by the opening / closing valve, a hydraulic pressure is generated in the second output hydraulic chamber 5, and this hydraulic pressure is supplied to the wheel cylinder.

The hydraulic pressure generated in the first and second output hydraulic pressure chambers 4 and 5 acts on the fail-safe piston 25 and the balance piston 26. As a result, the control valve 33 moves to the right in the figure against the biasing force of the spring 32. By the movement of the control valve 33, the annular groove 31b and the annular groove 29 are communicated with each other as shown in FIG. 4, and the high-pressure hydraulic pressure from the accumulator is changed from the flow passage 31a to the annular groove 3.
It is supplied to the power hydraulic chamber 12 through 1b → annular groove 29 → passage 30 → passage 30a → passage 21. Power hydraulic chamber 1
The hydraulic pressure introduced into 2 presses the booster piston 3a to the left and reduces the pedal effort of the brake pedal by the operator. In addition, the hydraulic pressure of the power hydraulic chamber at this time acts on the action piston 13 at the portion where the action piston 13 and the ball valve 18 contact each other, whereby a reaction force proportional to the operating force of the booster piston 3a acts on the push rod. In operation, the operator may be aware of the increased output of the hydraulic booster.

Even if the first output hydraulic pressure chamber system or the second output hydraulic pressure chamber system fails, the control valve 33 can be operated by either the fail-safe piston 25 or the balance piston 26. Safety is also high.

Next, a second embodiment of the present invention will be described with reference to the drawings. The second embodiment is aimed at improving the pedal feeling by preventing the initial reduction of the boosting ratio due to the sliding resistance when the pedal pedal is depressed. 5 is a sectional view of the hydraulic booster according to the embodiment of the present invention, and the main configuration is the same as that of the first embodiment. Therefore, here, the power hydraulic chamber 12 'having a configuration different from that of the first embodiment is used.
And the configuration of the hydraulic pressure introducing valve C ′ will be mainly described, and detailed description of portions having the same configuration as those of the first embodiment will be omitted.

In FIG. 5, reference numeral 1 denotes a cylinder body, and in this cylinder body 1, first and second booster pistons 3a and 3b are arranged in series, as in the first embodiment. Between the first booster piston 3a and the cylinder body 1 is a power hydraulic chamber 12 'having a configuration described later.
And a flow valve A for opening and closing the flow path to the power hydraulic chamber 12 '. A first output hydraulic pressure chamber 4 is provided between the first and second booster pistons 3a and 3b, and a second output hydraulic pressure is provided between the second booster piston 3b and the cylinder body 1. It has become room 5. The first and second output hydraulic chambers 4 and 5 are communicated with the reservoir 2 via an opening / closing valve B having the same structure. Further, between the hydraulic booster and the accumulator AC, a hydraulic pressure introduction valve C ′ that is indirectly opened / closed by the hydraulic pressure generated in the hydraulic booster.
Is arranged, and the hydraulic pressure accumulated in the accumulator AC can be introduced into the power hydraulic chamber 12 'by opening and closing the hydraulic pressure introducing valve C'. Further, a predetermined hydraulic pressure is constantly accumulated in the accumulator AC by the hydraulic pump P. The main structure is the same as that of the first embodiment. The configuration of each element of the power hydraulic chamber 12 'and the hydraulic pressure introducing valve C'of the hydraulic booster according to the second embodiment will be described below.

[Power hydraulic chamber 12 '] Power hydraulic chamber 1
2'is a booster piston 3 as shown in detail in FIG.
It is formed between a and the plug 20, and a spacer 19 is arranged in this power hydraulic chamber 12 '. on the other hand,
A passage 40 is formed in the plug 20 so as to connect the bower hydraulic chamber 12 'and the flow passage 21, and the flow passage 21 is connected to a hydraulic pressure introduction valve C'described later as in the first embodiment. ing. Spacer 19 arranged in the power hydraulic chamber 12 '
A ball valve 41 as a valve mechanism for opening and closing the passage 40 is arranged between the plug 20 and the plug 20. The ball valve 41 has a plug 20 via a spacer 19 by a booster piston biased rightward in the drawing by a spring 8 (disposed in the first output hydraulic chamber 4 and the second output hydraulic chamber 5). The flow path 21 is blocked by being pressed by. In the figure, reference numeral 42 denotes a stopper, and the movement amount of the spacer 19 is regulated by the stopper 42.

The ball valve 41 has a hydraulic pressure determined by the pre-pressure piston 51, the set spring 54, the pre-pressure valve 50 and the valve spring 52 when the brake is not operated (in the state shown in FIG. 7). When the hydraulic pressure becomes equal to or higher than a predetermined pressure, this hydraulic pressure opens the ball valve 41 through the passage 21 and the passage 40, and the brake fluid flows into the power hydraulic chamber 12 ′ through the flow passage 21, and the power hydraulic chamber 12 ′.
Has a function of holding a predetermined hydraulic pressure. Therefore, a predetermined hydraulic pressure is always accumulated in the power hydraulic chamber 12 '. Further, the ball valve 41 opens the passage 40 by the high-pressure brake fluid from the accumulator acting through the flow passage 21 during the brake operation, and introduces the fluid pressure from the accumulator into the power fluid pressure chamber 12 ′.

In the power hydraulic chamber 12 'having the above-described structure, when the brake is operated, the hydraulic pressure in the power hydraulic chamber is high to some extent as described above. Therefore, the hydraulic pressure from the accumulator acts to operate the booster piston. By the time, the time lag as in the conventional device is eliminated, the booster function with good responsiveness can be exhibited, and the brake feeling can be improved. At this time, the hydraulic pressure of the power hydraulic chamber 12 'also acts on the action piston 13 at the portion where the action piston 13 and the ball valve 18 contact each other, whereby a reaction force proportional to the operating force of the booster piston 3a is generated. It acts on the push rod so that the operator can be aware of the increased output of the hydraulic booster.

[Hydraulic Pressure Introduction Valve C '] The hydraulic pressure introduction valve applies the hydraulic pressure accumulated in the accumulator AC to the power hydraulic chamber 12'.
It constitutes the valve means for introducing into. This hydraulic pressure introducing valve C'is arranged between the hydraulic booster and the accumulator as in the first embodiment.

In FIG. 7, a valve sleeve 31 is attached to the valve body 24 by a plug 34. A small-diameter hole S and a large-diameter hole S ′ are continuously formed in the valve sleeve 31.
A control valve 33 and a pressure valve 50 are slidably arranged in the small-diameter hole S and a pressure piston 51 is slidably arranged in the large-diameter hole S ′. The control valve 33 and the pre-pressure valve 50 are configured as a common component, and a valve spring 52 is arranged between the control valve 33 and the pre-pressure valve 50. Due to the biasing force of the valve spring 52, the control valve 33 is always brought into contact with the balance piston 26, and the pressure valve 50
Is in contact with the pressure piston 51. Further, the pre-pressure piston 51 is urged to the left in the figure by a set spring 54 arranged between the pre-pressure piston 51 and the plug 34, and the balance of the urging forces of the set spring 54 and the valve spring 52 causes the pre-pressure piston 51 to move. 51 is always located as shown in the figure, and a throttle 53 is formed between the pressure piston 51 and the valve sleeve 31.

The valve sleeve 31 has an accumulator A.
Flow paths 55 and 56 are formed which communicate with the flow path 27 with C. The flow path 55 is communicated with an annular groove 55 a on the inner peripheral surface of the valve sleeve 31, and the flow path 56 is also communicated with the flow path 56. An annular groove 56a is formed on the inner peripheral surface of the valve sleeve 31. On the other hand, a flow passage 30 is formed in the control valve 33 and the pressure valve 50. The flow passage 30 has an annular groove 29 formed on the outer circumference of the control valve 33, an annular groove 57 formed on the outer circumference of the pressure valve 50, It communicates with the throttle 53 formed by the pressure piston 51 and the valve sleeve 31, and the hydraulic chamber 58 formed by the balance piston 26 and the valve sleeve 31. The annular groove 56a and the annular groove 29 constitute a first hydraulic pressure introducing valve mechanism, and the communication between the annular groove 31b and the annular groove 29 is normally disconnected as shown in the figure. In addition, the annular groove 55a and the annular groove 5
A second hydraulic pressure introducing valve mechanism is constituted by 7 and this valve always communicates with the annular grooves 55a and 57 as shown in the figure.

Therefore, in the non-operating state (in the state shown in FIG. 7), the hydraulic pressure from the accumulator AC is applied to the flow path 2.
7-channel 55-annular groove 55a-annular groove 57-channel 30-
It acts on the pressure piston 51 via the throttle 53. And at this time, the pressure piston 5
1, set spring 54, pre-pressure valve 5
0, when the hydraulic pressure determined by the valve spring 52 exceeds a predetermined pressure, the hydraulic fluid acts on the ball valve 41 via the flow passage 21 and the passage 40 to open the brake fluid into the power hydraulic chamber 12 '. As a result, a predetermined hydraulic pressure is always accumulated in the power hydraulic chamber 12 '. Also, the brake pedal is depressed, and as a result, the first and second output hydraulic chambers 4, 5
When the hydraulic pressure is generated in the hydraulic pressure generating valve, the hydraulic pressure introducing valve operates as follows depending on the hydraulic pressure generating states of the first and second output hydraulic pressure chambers 4 and 5.

That is, when the hydraulic pressure in the first and second output hydraulic pressure chambers 4 and 5 is lower than a predetermined hydraulic pressure, the ball valve 41 is separated from the flow passage 40 by the initial movement of the action piston 13. Fluid pressure from accumulator AC is flow path 2
7-channel 55-annular groove 55a-annular groove 57-channel 30-
The hydraulic pressure from the accumulator AC flows into the power hydraulic chamber 12 'through the throttle 53, and pushes the booster piston 3a to generate hydraulic pressure in the first and second output hydraulic chambers 4 and 5.

When the hydraulic pressure in the first and second output hydraulic chambers 4 and 5 becomes higher than a predetermined hydraulic pressure, the fail-safe piston 25 and the valve piston 26 are moved to the right in the figure by the hydraulic pressure and further controlled. The pre-pressure piston 51 is moved to the right in the figure against the urging force of the set spring 54 via the valve 33, the valve spring 52 and the pre-pressure valve 50. When the pre-pressure piston 51 moves, the urging force of the valve spring 52 moves the pre-pressure valve 50 to the right, the flow passage between the annular groove 55a and the annular groove 57 is blocked, and the annular groove 29 and the annular groove 5 are closed.
6a communicates with. As a result, the hydraulic pressure from the accumulator flows into the power hydraulic chamber 12 ′ through the annular groove 56a → the annular groove 29 → the flow passage 30 → the flow passage 21 → the passage 40 → the ball valve 41. The hydraulic pressure in the power hydraulic chamber at this time is determined by the fail-safe piston 25, the valve piston 26, and the control valve 33 which operate depending on the hydraulic pressures of the first and second output hydraulic chambers 4, 5.

The present embodiment is configured as described above,
It works as follows. First, when the brake is not operated, in the power hydraulic chamber 12 ', the pre-pressure piston 51, the set spring 54, the pre-pressure valve 5
0, the hydraulic pressure determined by the valve spring 52 always acts via the ball valve 41. As a result, a predetermined brake hydraulic pressure is constantly acting on the power hydraulic chamber 12 ', thereby preventing the boosting ratio from decreasing during brake operation.

When the brake pedal is stepped on in this state and the push rod 14 is pushed to the left in the figure, the action piston 13 first moves, whereby the ball valve 1
8 contacts the valve seat formed on the action piston 13 to cut off the communication between the first flow passage 14a and the flow passage 16 (that is,
Disconnect the communication between the reservoir and the power hydraulic chamber 12 '). At the same time, the ball valve 41 is separated from the flow path 40 by the leftward movement of the booster piston 3a, and a predetermined hydraulic pressure flows into the power hydraulic chamber 12 ', pressing the first booster piston 3a leftward. The spring 8 is compressed by the leftward movement of the first booster piston 3a, and the spring 9 shown in FIG. 3 moves the valve member 7 leftward to close the flow path 6.
Then, a hydraulic pressure is generated in the first output hydraulic chamber 4, and this hydraulic pressure is supplied to the wheel cylinder and moves the second booster piston 3b leftward in FIG. This makes the second
The output fluid pressure chamber 5 is also shut off from the flow path 6 by the on-off valve, a fluid pressure is generated in the second output fluid pressure chamber 5, and this fluid pressure is supplied to the wheel cylinder.

On the other hand, the hydraulic pressure generated in the first and second output hydraulic pressure chambers 4 and 5 also acts on the fail-safe piston 25 and the balance piston 26. When the hydraulic pressure generated in the first and second output hydraulic pressure chambers 4 and 5 is lower than the predetermined hydraulic pressure, the ball valve 41 is separated from the flow passage 40 by the initial movement of the action piston 13, and thus the accumulator AC. The fluid pressure from the flow channel 27 → flow channel 55 → annular groove 55a →
The hydraulic pressure from the accumulator AC flows into the power hydraulic chamber 12 ′ through the annular groove 57 → the flow path 30 → the throttle 53, and pushes the booster piston 3a to exert the booster function.

When the hydraulic pressure in the first and second output hydraulic chambers 4 and 5 becomes higher than a predetermined hydraulic pressure, the fail-safe piston 25 and the valve piston 26 move to the right in the figure due to the hydraulic pressure, and The pre-pressure piston 51 is moved to the right in the drawing against the biasing force of the set spring 54 via the control valve 33, the valve spring 52, and the pre-pressure valve 50. Pressure piston 5
When 1 moves, the pressure valve 50 moves to the right due to the urging force of the valve spring 52, and the annular groove 55
The flow path between a and the annular groove 57 is blocked, and the annular groove 29 and the annular groove 56a communicate with each other. As a result, the hydraulic pressure from the accumulator flows into the power hydraulic chamber 12 ′ through the flow passage 30 → passage 21 → passage 40 → ball valve 41. The hydraulic pressure flowing into the power hydraulic chamber 12 'presses the booster piston 3a to the left, and reduces the pedal effort of the brake pedal by the operator. At this time, the hydraulic pressure in the power hydraulic chamber is dependent on the hydraulic pressures in the first and second output hydraulic chambers 4 and 5, the fail-safe piston 25, the valve piston 26,
It is determined by the control valve 33. As described above, in the present embodiment, the valve means is constituted by the control valve 33, the pressure valve 50 and the valve spring 52 arranged between them, which have a common structure, and two types of control can be realized. It is like this.

When boosted, the hydraulic pressure in the power hydraulic chamber 12 'acts on the action piston 13 at the portion where the action piston 13 and the ball valve 18 contact each other, and is proportional to the operating force of the booster piston 3a. The reaction force acts on the push rod so that the operator can be aware of the increased output of the hydraulic booster. In the power hydraulic chamber 12 'having the above-described structure, when the brake is operated, the hydraulic pressure in the power hydraulic chamber is high to a certain extent as described above, and therefore, the hydraulic pressure from the accumulator acts to activate the booster piston. As with the conventional device, the time lag is eliminated and the booster function with good responsiveness can be exhibited, and the brake feeling can be improved. In this embodiment as well, even if a failure occurs in either the first or second output hydraulic chamber system, the fail-safe piston 25,
Since the control valve 33 can be operated via either of the balance pistons 26, the safety is high.

[0040]

As described in detail above, according to the present invention,
Since the opening and closing of the hydraulic pressure introduction valve of the hydraulic booster is separated from the operation of the operating member and is indirectly opened and closed by the hydraulic pressure generated in the hydraulic booster, the entire device can be operated with the conventional hydraulic pressure. The device can be made smaller than the booster, and the weight and cost of the device can be reduced. Further, since the flow valve is composed of the ball valve and the action piston, the structure of the valve is simplified and the boost ratio is selected because the reaction pressure receiving area is set by the ball valve and the action piston. It will be easier. Since the action piston is formed of a cylindrical member having the same cross-sectional area, machining of the sliding diameter portion becomes extremely easy, and if the ball valve and the action piston have the same diameter, machining of the booster piston becomes easier. Further, by dividing the liquid chamber by the valve mechanism 41 as shown in FIG. 5, the power hydraulic chamber 12
Since the hydraulic pressure of the can be kept high to a certain degree from the normal time, there is no time lag as in the conventional device until the booster piston operates due to the hydraulic pressure from the accumulator, and a booster function with good responsiveness is provided. It can be exerted and the brake feeling can be improved. It is possible to obtain excellent effects such as.

[Brief description of drawings]

FIG. 1 is a side sectional view of a hydraulic booster according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a flow valve and a power hydraulic chamber in FIG.

FIG. 3 is an enlarged view of an on-off valve in FIG.

FIG. 4 is an enlarged view of the hydraulic pressure introduction valve in FIG.

FIG. 5 is a side sectional view of a hydraulic booster according to a second embodiment of the present invention.

FIG. 6 is an enlarged view of a power hydraulic chamber in FIG.

FIG. 7 is an enlarged view of the hydraulic pressure introduction valve in FIG.

[Explanation of symbols]

 1 Cylinder body 2 Reservoir 3a First booster piston 3b Second booster piston 4 First output hydraulic chamber 5 Second output hydraulic chamber 6 Flow path 7 Valve member 8, 9 Spring 10, 11 Washer 12, 12 'Power Hydraulic chamber 13, 31 Valve sleeve 14 Input member (push rod) 15 Liquid chamber 18 Valve body (ball valve) 25 Fail-safe piston 26 Valve piston 41 Valve mechanism (ball valve) AC Hydraulic pressure source (accumulator) P Pump A, A'Distribution valve B Opening valve C, C'Liquid pressure introduction valve

Claims (6)

[Claims] 1. A hydraulic booster comprising: a cylinder body 1; and an output hydraulic chamber 4 arranged in the cylinder body and connecting the inside of the cylinder body to a wheel cylinder.
And a booster piston 3a that receives the hydraulic pressure in the power hydraulic chamber 12, and a flow valve that is controlled by the relative movement of the booster piston 3a and the action piston 13 to open and close the communication between the power hydraulic chamber 12 and the reservoir 2. A, an on-off valve B that disconnects the communication between the output hydraulic chamber and the reservoir by the movement of the action piston, a hydraulic pressure source that is operated by the hydraulic pressure generated in the output hydraulic chamber, and the power hydraulic chamber. A fluid pressure introducing valve C communicating with the flow valve A,
It has an action piston 13 slidably provided in the axial direction of the booster piston 3a, first flow paths 14a and 14b formed in the action piston 13, and a valve body 18 for opening and closing the first flow path 14. When the action piston 13 is actuated, the valve body 18 is
And the booster piston 3a in cooperation with the first flow path 1
4. A hydraulic booster characterized in that it is configured to be able to close 4. 2. The valve body 18 has a spherical shape, the valve body is disposed between the action piston 13 and the booster piston 3a, and the diameter of the valve body is formed to be substantially the same as the diameter of the action piston 13. The hydraulic booster according to claim 1, wherein the hydraulic booster is provided. 3. The power hydraulic chamber 12 is provided with a valve mechanism 41 for opening and closing a flow path with the hydraulic pressure introducing valve C operated by the hydraulic pressure generated in the output hydraulic chamber. The hydraulic booster according to claim 1. 4. The fluid pressure introducing valve C comprises a valve sleeve 3
1 and valve means 33 and 50 slidably arranged in the valve sleeve 31, and the valve means is controlled by a valve piston 26 that is operated by the hydraulic pressure generated in the output hydraulic chamber. The hydraulic booster according to claim 1, which is configured to connect the source AC and the power hydraulic chamber 12 to each other. 5. The valve means has a control valve 33, a pressure valve 50, and a valve spring 52 arranged between these valves. The control valve 33 is normally a hydraulic pressure source and a power hydraulic chamber. The hydraulic pressure source and the power hydraulic chamber 12 are communicated with each other when the hydraulic pressure is generated in the output hydraulic chamber and the pressure valve 50 is always connected to the hydraulic pressure source and the power hydraulic chamber 12. 5. It is configured such that the hydraulic pressure source and the power hydraulic pressure chamber 12 are cut off from each other when the hydraulic pressure is generated in the output hydraulic pressure chamber while communicating with the power hydraulic pressure chamber 12 through the throttle. Hydraulic booster. 6. The valve piston 26 receives the hydraulic pressure of one system of the brake system piping system separated into two systems, and the one end receives the hydraulic pressure of the other system coaxially with the valve piston 26, The hydraulic booster according to claim 4, further comprising a fail-safe piston 25, the other end of which is in contact with the valve piston 26.