JPH037653A - Liquid pressure booster - Google Patents

Abstract

PURPOSE:To provide brake application in different modes simply by operating a power piston with the liquid pressure, which is introduced by a selector valve changed over when certain operating conditions are met, and thereby allowing a liquid pressure booster device to give an output automatically regardless of the input shaft. CONSTITUTION:Power piston 6 of a liquid pressure booster device 1 as a braking force doubler device is operated with the liquid pressure introduced into No.1 power chamber 15 through the action of an input shaft 17. When in addition thereto, certain specified conditions are met, a selector valve 61 is changed over to introduced the liquid pressure to No.2 power chamber 48, and now the power piston 6 is operated with this liquid pressure automatically regardless of the operation of the input shaft 17. This allows accomplishment of brake application in different modes simply; i.e., auto-braking for avoidance of obstacle or any hazardous state, stop hold braking actuated by a stop signal given by a speed sensor when the car is at a standstill, and manual braking applied with a manual switch.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hydraulic booster used in a brake booster, etc., which performs servo control of input and output at a predetermined servo ratio. be.

[Prior Art] In general, a hydraulic booster is disclosed in Japanese Patent Application Laid-Open No. 61-94865, for example.
As shown in the publication, a power piston slidably fitted into a housing, a power chamber into which hydraulic pressure acting on one end of the power piston is introduced, and a hydraulic pressure source or It includes a control valve that switches and controls communication with the reservoir, an input shaft that operates the control valve, and an output shaft that is connected to the power piston. By operating the input shaft and switching the control valve, hydraulic pressure from a hydraulic pressure source is introduced into the power chamber, and the hydraulic pressure operates the power piston to output from the output shaft. In that case, the hydraulic booster performs so-called servo control, which controls the magnitude of the output of the output shaft in response to the magnitude of the input of the input shaft.

[Problems to be Solved by the Invention] By the way, in any of these conventional hydraulic boosters, the hydraulic booster is activated by moving the input shaft forward by pressing the pedal or the like and switching the control valve. It is now output for the first time. Therefore, conventionally, it has not been possible to automatically operate the hydraulic booster regardless of the operation of the input shaft.

The present invention has been made in view of these circumstances, and its purpose is to provide a hydraulic booster that can be automatically operated.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a second power chamber into which hydraulic pressure acting on another power piston in the power chamber is introduced, and the second power chamber It is characterized in that it is connected to a hydraulic pressure source via a switching valve that automatically switches and operates under predetermined conditions.

"Function" 3- In the hydraulic pressure booster according to the present invention having such a configuration, the power piston is operated by the hydraulic pressure introduced into the power chamber by the operation of the input shaft, as in the conventional case. Then, when the predetermined conditions are met, the switching valve switches and operates, and the second
Hydraulic pressure is introduced into the power chamber. The power piston is actuated by this positive fluid. Therefore, the hydraulic booster automatically operates regardless of the operation of the input shaft.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of a hydraulic booster according to the present invention applied as a brake booster.

As shown in FIG. 1, the brake booster 1 includes a housing 2 formed in a substantially cylindrical shape. The housing 2 has a first hole 3 and a second hole 4 which are opened at the right end and left end of the housing 2, respectively, and these first and second holes.
A third hole 5 communicating with the second holes 3 and 4 is coaxially bored.

The diameter of the second hole 4 is set larger than the diameter of the third hole 5. It is.

A power piston 6 is disposed across the second and third holes 4 and 5. This power piston 6 includes a first piston portion 7 that slides liquid-tightly within the third hole 5, and a second piston portion having a larger diameter than the first piston portion 7 that slides liquid-tightly within the second hole 4. 8
It is equipped with Further, the power piston 6 has fourth and fifth holes 9 and 10 opened at the left and right ends, respectively, and a sixth hole 11 that communicates these holes 9 and 10, which are coaxially bored. .

A plug 12 is fixed to the right end of the housing 2 to close the first hole 3 in a liquid-tight manner. Further, the intermediate portion 13 of the plug 12 is fitted into the third hole 5 in a liquid-tight manner, and the left end portion 14 of the plug 12 is inserted into the fourth hole 9 of the power stone 6. Between this plug 12 and the power piston 6,
A first power chamber 15 is formed.

A seventh hole 16 is bored in the plug 12 coaxially with the fourth to sixth holes 9 to 11. This seventh hole 16 has an input shaft 1
7 is slidably inserted in a fluid-tight manner. A flange portion 18 is formed at the left end of the input shaft 17, and when the input shaft 17 moves backward, that is, to the right, this flange portion 1
8 comes into contact with the left end of the plug 12, so that the input shaft 7 can no longer move to the right. This position is the retraction limit position of the input shaft 17. Further, the flange portion 18 is disposed between the stepped portion 9 between the fourth hole 9 and the sixth hole 11 and a ring-shaped retaining member 20 attached to the power piston 6, so that the input shaft 17 When the input shaft 17 moves to the right with respect to the power piston 6, the flange portion 18 comes into contact with the retaining member 20, thereby preventing the input shaft 17 from being removed from the power piston 6. Therefore, the flange portion 18 can move relative to the power piston 6 between the stepped portion 19 and the retaining member 20. Furthermore, a cylindrical member 21 is provided at the left end of the input shaft 17. On the other hand, the right end of the input shaft 17 is connected to a brake pedal (not shown) via a connecting member 22.

An axial passage 24 communicating with the hole 23 of the cylindrical member 21 is bored at approximately the center of the input shaft 17, and a diametric passage 25 communicating with the right end of this passage 24 is bored. . This passage 25 communicates with an annular groove 26 formed in the plug 12 , which communicates via a diametrical passage 27 in the plug 12 with an annular chamber 28 between the housing 2 and the plug 12 . is connected to. Furthermore, the annular chamber 28 communicates with a reservoir 31 via an outlet 29 formed in the housing 2 and an outlet conduit 30.

A valve body 33 having a ball 32 at the right end is slidably disposed in the sixth hole 11 of the power piston 6. Also, the 6th
A cylindrical valve seat member 34 is fixed at the right end of the hole 11, and the ball 32 of the valve body 33 is seated on this valve seat member 34 by the biasing force of a compression coil spring 35. A pressure chamber 37 is defined by a sealing portion between the ball 32 and the valve seat portion 34 and a sealing member 36 that seals the valve body 33. Further, the left end portion of the cylindrical portion 7 material 21 is inserted into the hole 38 of the valve seat member 34, and its end surface is in contact with the ball 32.

A compression coil spring 39 is disposed between the cylindrical member 21 and the valve seat member 34. This spring 39 constantly biases the input shaft 17 and the cylindrical member 21 in the direction in which the cylindrical member 21 moves away from the valve body 33, that is, in the right direction, and the force on the input shaft 17 is strong enough to overcome the biasing force of the spring 39. When no leftward force having the magnitude of is applied, the input shaft 17 is set to the backward limit position. Then, the input shaft 17 is connected to the spring 3
When the ball 32 moves forward, that is, to the left, with respect to the power piston 6 against the biasing force 9, the left end of the cylindrical member 21 moves the valve body 33 to the left, so that the ball 32 moves away from the valve seat member 34. By leaving the seat, the pressure chamber 37 and the first power chamber 15 are brought into communication. That is, the cylindrical member 21,
A control valve 40 is constituted by a valve body 33 having a ball 32 and a valve seat member 34.

The right end portion of the output shaft 41 is attached to the fifth hole 10 of the power piston 6 by a ring-shaped retaining member 42 attached to the power piston 6 . This output shaft 41 is adapted to operate a piston of a brake mask cylinder (not shown) fixed to the left end of the housing 2. A return spring 45 disposed between a plug 43 screwed into the housing 2 and a stepped portion 44 formed at the right end of the output shaft 41 causes the output shaft 41 and the power piston 6 to constantly move toward the right. Forced.

When a leftward force large enough to overcome the biasing force of the spring 45 is not applied to the power piston 6, the right end of the power piston 6 comes into contact with the plug 12, and the power piston 6 is held at the backward limit position. ing.

When the power piston 6 and the input shaft 17 are both at the retracting limit position, the flange portion 18 is spaced apart from the step portion 19 and the retaining member 20. That is, when the input shaft 17 is not in operation, the input shaft 17
When the flange portion 18 comes into contact with the left end portion of the plug 12, the retaining member 2 is held against the power piston 6.
It is held at a predetermined forward position away from 0. In this held position, the cylindrical member 21 at the left end of the input shaft 17
The left end of is in contact with the ball 32.

A chamber 46 is formed between the power piston 6 and the output shaft 41. This chamber 46 communicates with the first power chamber 15 through a passage 47 formed in the power piston 6.

Further, the left end of the valve body 33 faces the inside of the chamber 46 . On the other hand, a second power chamber 48 is formed between the housing 2 of the second hole 4 and the power piston 6.

The pressure chamber 37 is connected to the first piston part 7 and the second piston part 7 through a passage 49.
It communicates with an annular groove 5o provided on the outer periphery of the power piston 6 between it and the piston part 8.

Further, the groove 50 communicates with a supply port 53 via a hole 51 formed in the housing 2 and a filter 52. This supply port 53 is connected to the accumulator 55 via a supply conduit 54.
and the discharge side of the pump 56, and the suction side of the pump 56 communicates with the reservoir 31. Pump 56 and accumulator 55 constitute the hydraulic pressure source of the present invention. A check valve 57 is interposed between the accumulator 55 and the pump 56, which allows liquid to flow from the pump 56 toward the accumulator 55, but blocks liquid from flowing in the opposite direction. There is.

Furthermore, the housing 2 has a first connection port 58 communicating with the first power chamber 15 and a second connection port 5 communicating with the second power chamber 48.
9 are provided respectively.

The first connection port 58 is connected to a first port 61a of a three-bottom, two-position switching valve 61 via a conduit 60. Switching valve 6
The second port 61b of 1 is connected to the second connection port 5 via the conduit 62.
9 is connected. The conduit 60 is provided with an orifice 63 and a check valve 64 in parallel, which allows only the flow of liquid from the second connection port 59 to the first connection port 58 . Further, the second connection port 59 is connected to the reservoir 31 via the check valve 65.
It is connected to the. This check valve 65 is designed to only allow liquid to flow from the reservoir 31 toward the second connection port 59. On the other hand, the third bow l-61c of the switching valve 61 is connected to the accumulator 55.

11. The switching valve 61 is formed of a solenoid valve, and is normally set by a spring to the position (2), which connects the first port 61a and the second boat 62b.

When predetermined operating conditions are met, the control device 66 energizes the solenoid of the switching valve 61, so that the switching valve 61 connects the second port 611:l and the third port 1□ 61c.
The device can be switched to the second device H that connects the device.

Next, the operation of this embodiment will be explained.

When the pump 56 is driven, the hydraulic fluid is introduced from the reservoir 31 into the accumulator 55 via the check valve 57, and the supply conduit 54, supply port 53, filter 52, and passage 51 are introduced into the accumulator 55.
, groove 50, and passage 49 into the pressure chamber 37. A constant level of hydraulic pressure is always maintained in the pressure chamber 37 and the accumulator 55.

In the normal state, the switching valve 61 is set in the first device I, so the first connection port 58 is connected to the second connection port 59 via the orifice 63.

In a state where the brake is not operated, 2-brake booster 1 is connected to input shaft 17 and power piston 6.
, and the output shaft 41 are both at the backward limit position.

In this state, the ball 32 of the control valve 40 is seated on the valve seat member 34, and the cylindrical member 21 is seated on the ball 32. Therefore, the first power chamber 15 is isolated from the pressure chamber 37 and the reservoir 31. Therefore, the inside of the first power chamber 15 is maintained at a hydraulic pressure that is approximately balanced with the spring force of the return spring 45.

When the brake pedal (not shown) is depressed for braking, the input shaft 17 moves to the left and the ball 32 touches the valve seat member 34.
immediately leaves the seat, and the pressure fluid in the pressure chamber 37 flows into the first power chamber 1.
It will be introduced in 5. This pressure fluid causes the power piston 6
moves forward with a resistance of 1 to the elastic force of the spring 45, so the output shaft 41 outputs an output to actuate the piston of the mask cylinder.

Braking is thereby performed. At this time, as the second piston portion 8 moves, the inside of the second power chamber 48 tends to become negative pressure, but the hydraulic fluid at atmospheric pressure is sucked in from the reservoir 31 via the check valve 65. , second power chamber 4
8 will never become negative pressure. Therefore, the power piston 6 can move smoothly without resistance.

Moreover, since the hydraulic pressure in the first power chamber 15 also acts on the input shaft 17, the force applied to the input shaft 17 due to this hydraulic pressure is transmitted to the driver as a brake reaction force. As the power piston 6 moves, the valve seat member 34 also moves to the left, and when the valve seat member 34 comes into contact with the ball 32, communication between the pressure chamber 37 and the first power chamber 15 is cut off. For this reason, no more pressurized fluid is introduced into the NIO 1 power chamber 15, so the movement of the power piston 6 is stopped. As a result, the amount of depression of the brake pedal, that is, the amount corresponding to the input of the input shaft 17,
Pressure fluid is introduced into the first power chamber 15 .

Therefore, the output of the output shaft 41 has a magnitude corresponding to the input of the input shaft 17.

Further, the pressure liquid in the first power chamber 15 passes through the passage 47 to the chamber 4.
It will also be introduced in 6. Since the hydraulic pressure in this chamber 46 comes to act on the left end of the valve body 33, the force due to the hydraulic pressure in the first power chamber 5 applied to the valve body 33 is reduced and the valve body 33 moves to the left. Never. This eliminates the need to increase the elastic force of the spring 35 so much.

By the way, the hydraulic pressure in the first power chamber 15 is transmitted from the first connection port 58 to the conduit 60, the orifice 63, the switching valve 61, and the second
It is also introduced into the second power chamber 48 via the connection port 59. At this time, the pressure liquid that has passed through the orifice 63 is transferred to the reservoir 31.
However, the check valve 65 prevents the pressure liquid from flowing into the reservoir 31. As a result, the pressure fluid is introduced only into the second power chamber 48. Since the pressure liquid is constricted by the orifice 63, the pressure in the second power chamber 48 increases later than the pressure in the first power chamber 15. Therefore, for example, the input shaft 17
When the input is stopped at an intermediate load point and the valve seat member 34 comes into contact with the ball 32, the pressure in the first power chamber 15 no longer increases. However, since the pressure in the second power chamber 48 increases with a delay, even if the input to the input shaft 17 stops, the output shaft 48
The output of 2 is further increased, and the braking force is also increased to a predetermined maximum level. That is, an aftereffect effect of the brake is performed.

When the brake pedal is released from the brake pedal to release the brake, the input shaft 17 moves back significantly until the flange portion 18 contacts the retaining member 20 with respect to the power piston 6. Therefore, the left end of the cylindrical member 21 is separated from the ball 32, and the first power chamber 15 is communicated with the reservoir 31, and its pressure is reduced. Therefore, the power piston 6 retreats due to the elastic force of the spring 45, and accordingly, the pressure fluid in the first power chamber 15 is discharged to the reservoir 31, and the pressure fluid in the second power chamber 48 is also switched. Valve 61, check valve 6
4. It is discharged to the reservoir 31 via the first power chamber 15.

At this time, the pressure fluid in the second power chamber 48 is not influenced by the flow orifice 63 mainly through the check valve 64. Moreover, since the cylindrical member 21 is far away from the ball 32 and a large flow path area is formed, the first and second power chambers 1
Pressure fluid within 5° 48 will be quickly drained into the reservoir 31. Therefore, the power piston 6 quickly retreats.

=16- When the flange portion 18 comes into contact with the left end of the plug 12, the input shaft 17 will no longer move back, and only the power piston 6 will move back. Therefore, the flange portion 18 becomes separated from the retaining member 20. When the right end of the power piston 6 comes into contact with the plug 12, the power piston 6 stops retracting and reaches the retracting limit position.

In this state, the input shaft is at a predetermined position advanced relative to the power piston 6, and the tip of the cylindrical member 21 is in contact with the ball 32.

Next, it is based on various signals such as an overspeed signal or a stop signal from a speed sensor, a logical product of a speed signal from a speed sensor and a steering wheel steering angle signal, or an obstacle detection signal from an obstacle detection sensor. , switching valve 6
1, the control device 66 switches the switching valve 6
Energize solenoid 1. As a result, the switching valve 61 is switched to the second position (3). As a result, the hydraulic pressure of the accumulator 55 is introduced into the second power chamber 48 via the switching valve 61. Since this hydraulic pressure acts on the second piston portion 8, the power piston 6 moves forward and the output shaft 41 outputs an output. This output activates the brake mask cylinder and automatically performs braking.

When the operating conditions of the switching valve are no longer satisfied due to this automatic braking, the control device 66 de-energizes the solenoid.
The switching valve 61 is switched to the first position (3). For this reason,
The pressure liquid in the second power chamber 48 flows into the reservoir 31 through the switching valve 61, the check valve 64, the first power chamber 15, the gap between the ball 32 and the cylindrical member 21, etc., as in the normal case described above. It is discharged. Therefore, the power piston 6 is returned to the rearward limit position by the spring 45, and the brake is released.

FIG. 2 is a sectional view similar to FIG. 1 showing another embodiment of the invention. It should be noted that the same components as those in the above-mentioned embodiments are given the same reference numerals, and detailed explanations thereof will be omitted.

In this embodiment, a 3-point, 3-position switching valve 61' is used in place of the 3-point, 2-position switching valve 61 of the previous embodiment. Also, the first connection port 58, check valve 64, 75, and orifice 63 of the previous embodiment are omitted.

The switching valve 61- is connected to the first bow 1-61'a and the second bow.
1-61 = 1st position straight weight where b is connected, 2nd position ■ where all 3 boats are cut off and in a neutral state, 3rd position
The third boat 61'c and the second boat 61'b communicate with each other.
Position ■ is set. Dai 1 Bo 1□ 61-
a is connected to the reservoir 31, and the second port 61'
b is connected to the second connection port 59, and the third port 61-c is further connected to the accumulator 55. The switching valve 61' is normally set at the first port 61'a, but is switched to the second position (2) or the third position (2) by the control device 66 when predetermined operating conditions are met. .

In this embodiment, when a predetermined first operating condition for the switching valve 61' is met, the control device 66 energizes the solenoid to switch the switching valve 61- to the third position (2). As a result, the pressure fluid in the accumulator 55 is introduced into the second power chamber 48 . Since the hydraulic pressure in the second power chamber 19-48 acts on the second piston portion 8, the power piston 6 moves forward and braking is performed.

When a predetermined brake force is obtained and a predetermined second operating condition is reached, the control device 66 switches the switching valve 61 to the second position (2). As a result, the second power chamber 48 is connected to the accumulator 55.
and from the reservoir 31. Second power chamber 4
8 is maintained at that hydraulic pressure. If the second operating condition is not satisfied, the switching valve 61
The brake force is further increased by further increasing the hydraulic pressure in the second power chamber 48, and if the first operating condition is not established, the switching valve 61' is switched to the first position. Pressure fluid in the second power chamber 48 is discharged to the reservoir 33, and the brake is released. In this way, by providing the switching valve 61' with the second position (2) that maintains the hydraulic pressure in the second power chamber 48 constant, the hydraulic pressure in the second power chamber 48 can be easily adjusted to a desired level. be able to.

FIG. 3 is a diagram showing still another embodiment of the present invention. Similarly, the same components as in the embodiment shown in FIG. ).

In this embodiment, second and third switching valves 67, 68, a pressure regulating valve 69, and a second accumulator 70 are further provided in the embodiment of FIG. That is, in the conduit 60 between the first connection port 58 and the orifice 63, a second switching valve 67 and a pressure regulating valve 69 connected in series and a third switching valve 68 are arranged in parallel. . In that case, the second and third switching valves 67, 68 are formed by two-point, two-position valves, and normally the second switching valve 67 is in the blocking position (2), and the third switching valve 68 is in the communicating position (H). are set respectively. Further, on the downstream side of the orifice 63, a hydraulic pressure absorption device 70 consisting of an accumulator or the like is provided.

The operation of this embodiment will be explained.

In the illustrated normal state, the operation is almost the same as in the case of FIG. In this case, the pressure of the liquid flowing from the first power chamber 15 when the input shaft 17 is actuated is absorbed by a predetermined amount by the hydraulic pressure absorbing device 70, so that the pressure of the liquid flowing from the first power chamber 15 is absorbed by the hydraulic pressure absorbing device 70.
The rise in pressure within the power chamber 48 is further delayed. As a result, the brake aftereffect effect can be performed even more effectively.

On the other hand, when the second switching valve 67 is switched to the communication position (3) and the third switching valve 68 is switched to the cutoff position (direct load), the pressure fluid from the first power chamber 15 is transferred to the second power chamber via the pressure regulating valve 69. It will be introduced within 48. The maximum pressure introduced into the second power chamber 48 by this pressure regulating valve 7o is smaller than that in the normal state described above. Therefore, the braking force in this case is weaker than that in the normal state, so the final vehicle The deceleration is also reduced. In this way, the final vehicle deceleration can be changed by the pressure regulating valve 69.

On the other hand, the automatic braking operation by the switching valve 61 is the same as in the embodiment shown in FIG. 1, so its explanation will be omitted.

In each of the above-mentioned embodiments, it is clear that the present invention is applied to a brake booster, but it can also be applied to other hydraulic pressure boosters other than brake boosters, such as clutch boosters. Needless to say, it can also be used in power devices.

(Effects of the Invention) As is clear from the above explanation, the hydraulic booster according to the present invention uses the hydraulic pressure introduced by the switching valve that is switched when predetermined operating conditions are met to boost the power piston. , the hydraulic booster can be automatically output regardless of the input shaft. Therefore, for example, if the hydraulic pressure booster of the present invention is applied to a brake booster, automatic brakes for avoiding obstacles or dangerous situations, etc., and stop-holding brakes activated by a stop signal from a speed sensor when the vehicle is stopped. , it becomes possible to easily obtain various types of brakes such as a manual brake using a manual switch.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment in which a hydraulic pressure booster according to the present invention is applied to a brake booster, FIG. 2 is a longitudinal cross-sectional view showing another embodiment of the present invention, and FIG. FIG. 3 is a vertical cross-sectional view showing still another embodiment of the present invention. 1... Brake booster (hydraulic pressure booster), 2...
Housing, 6... Power piston, 12...
Plug (stopper means), 15...first power chamber, 1
7... Input shaft, 20... Retaining member, 31...
・Reservoir, 40... Control valve, 41... Output line
48...Second power chamber, 55...Accumulator (hydraulic pressure source), 56...Pump (hydraulic pressure source), 61.61'.
・・Switching valve

Claims (1)

[Scope of Claims] A power piston that is slidably fitted into a hole in a housing, a first power chamber into which hydraulic pressure acting on the power piston is introduced, and a hydraulic pressure source that generates the hydraulic pressure. , an input shaft slidably inserted into the power piston, an output shaft connected to the power piston, and communication between the first power chamber and the hydraulic pressure source when the input shaft is not in operation. and a control valve that operates when the input shaft moves forward toward the power piston to communicate the first power chamber and the hydraulic pressure source, further comprising: , a second power chamber into which hydraulic pressure acting on the power piston is introduced; normally this second power chamber is communicated with the reservoir and is isolated from the hydraulic pressure source, and when predetermined operating conditions are met; A hydraulic booster comprising: a switching valve that operates to isolate the second power chamber from the reservoir and communicate with the hydraulic pressure source.