JPH0789431A - Pneumatic type booster - Google Patents

Abstract

PURPOSE:To prevent the generation of noise by suppressing the discharge of the compressed air in a pressure varying chamber through the opened port part of a valve body, by installing a check valve which permits only the inflow of atmosphere into the valve body part, on the atmosphere opened port part inside the valve body. CONSTITUTION:The compressed air and the atmosphere which flow into a pressure varying chamber 5 are discharged into the vacuum source of an engine, passing through a pressure varying chamber communication passage 63, the second atmosphere valve 82, the second communication passage 59 of a plunger, center passage 57, the first communication passage 58 of the plunger, vacuum valve 75, vacuum passage 62, and a constant pressure chamber 4. In this case, even if the first atmosphere valve 76 is opened by the temporary inside deflection of the first valve body 73 for a control valve by the pressure of the compressed air, the outside discharge of the compressed air from an opened port part 29 can be suppressed, since a check valve 71 is installed on an opened port 29 side. Accordingly, the generation of the noise can be prevented, by the discharge of the compressed air passing through the opened port part 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic booster used for a braking system of an automobile.

[0002]

2. Description of the Related Art As an example of a conventional pneumatic booster, there is an apparatus configured as follows. That is, in this pneumatic booster, the inside of the housing is divided into a constant pressure chamber and a variable pressure chamber by a power piston equipped with a diaphragm, and one end side of a substantially cylindrical valve body is airtightly attached to the power piston. The other end of the valve body is airtightly passed through a hole formed in the rear surface of the housing so as to protrude outside the housing to communicate the inside of the valve body with the atmosphere. In the valve body, a plunger interlocked with the input shaft connected to the brake pedal, and a poppet valve as an opening / closing valve that opens / closes according to the relative displacement of the input shaft, the plunger and the valve body are arranged and responds to the input shaft. The pneumatic device is connected to the variable pressure chamber via the compressed air valve that opens and closes.

When the poppet valve is opened / closed, the constant pressure chamber and the variable pressure chamber are connected / disconnected through the vacuum passage formed in the valve body, and the pressure is changed through the internal space of the valve body and the atmosphere passage formed in the valve body. The communication between the chamber and the atmosphere is cut off, and compressed air is supplied from the pneumatic device to the variable pressure chamber in response to the opening operation of the compressed air valve to switch the internal pressure of the variable pressure chamber to vacuum pressure, atmospheric pressure or compressed air pressure. I am trying. In this pneumatic booster, a pressure difference is generated between the constant pressure chamber and the pressure changing chamber by setting the internal pressure of the pressure changing chamber to the atmospheric pressure, and the power piston is moved forward by this pressure difference to pass through the output rod. It is designed to output boosted thrust. Further, by setting the internal pressure of the variable pressure chamber to the compressed air pressure, a larger differential pressure is obtained and a larger thrust is generated.

[0004]

In the pneumatic booster described above, when the internal pressure of the variable pressure chamber is set to the compressed air pressure, the internal pressure of the variable pressure chamber is partitioned by the poppet valve when the brake pedal is suddenly returned. Since the pressure is higher than the atmospheric pressure, the poppet valve is pushed and opened, and the compressed air in the variable pressure chamber is discharged to the outside through the opening of the valve body, which causes noise.

The present invention has been made in view of the above circumstances, and provides a pneumatic booster capable of suppressing the generation of noise by suppressing the discharge of compressed air in a variable pressure chamber through the opening of a valve body. The purpose is to provide.

[0006]

To achieve the above object, the present invention defines a constant pressure chamber and a variable pressure chamber in a housing by a power piston having a diaphragm, and the power piston has a substantially cylindrical shape. One end of the valve body is attached airtightly, and the other end of the valve body is passed airtightly through a hole formed on the rear surface of the housing to project outside the housing to communicate the inside of the valve body with the atmosphere and the valve body. A plunger interlocking with the input shaft and an opening / closing valve that opens and closes according to the relative displacement of the input shaft, the plunger and the valve body are provided therein, and a pneumatic device is provided through a compressed air valve that opens and closes in response to the input shaft. Is connected to the variable pressure chamber, and the open / close valve is opened / closed to connect / disconnect the constant pressure chamber and the variable pressure chamber through the vacuum passage formed in the valve body, and the internal space / body of the valve body The inside and outside of the variable pressure chamber is evacuated by supplying compressed air from the pneumatic device to the variable pressure chamber in response to the opening operation of the compressed air valve while connecting and disconnecting the variable pressure chamber from the atmosphere through the atmosphere passage formed in the body. In a pneumatic booster that switches and sets pressure, atmospheric pressure or compressed air pressure, a check valve that allows only the inflow of air into the valve body is provided on the atmosphere opening side inside the valve body. .

[0007]

With this structure, when the internal pressure of the variable pressure chamber is set to the compressed air pressure and then the brake pedal is suddenly released, the on-off valve is temporarily opened by the pressure difference between the compressed air and the atmospheric pressure. Even if the compressed air passes through the on-off valve, the flow of the compressed air is suppressed by the check valve provided on the opening side.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic booster according to an embodiment of the present invention will be described below with reference to FIG. In the figure, the inside of the housing 1 is divided into a constant pressure chamber (negative pressure chamber) 4 and a variable pressure chamber 5 by a power piston 3 having a diaphragm 2.
Is connected to a vacuum source 7 on the engine (not shown) side through a constant pressure side inlet 6, and a negative pressure is introduced. A casing 8 is connected to the rear surface side of the housing 1, and a pressure accumulating chamber 9 is formed by the rear surface of the housing 1 and the casing 8.

The accumulator 9 is provided with a compressed air side inlet 10, and a compressed air generating mechanism 11 is connected to the compressed air side inlet 10. The compressed air generating mechanism 11 is a motor
A compressor 13 driven by 12 to generate compressed air, and a compressor
A dryer 15 provided in the middle of a pipe 14 that connects 13 and the compressed air side inlet 10, a portion of the pipe 14 between the dryer 15 and the compressor 13, and between the dryer 15 and the compressed air side inlet 10. Compressed air side first and second check valves respectively provided in the
It has 16 and 17. The portion of the pipe 14 between the second check valve 17 on the compressed air side and the dryer 15 and the vacuum source 7 are connected to the pipe 18.
A normally open solenoid valve 19 is provided in the middle of the pipe 18. A portion of the pipe 18 between the electromagnetic valve 19 and the vacuum source 7 and the constant pressure side inlet 6 are connected via a pipe 20.

A compressed air generating mechanism 11 is installed in the pressure accumulating chamber 9.
The compressed air is stored in advance by the operation of. In this embodiment, a pneumatic device is composed of the compressed air generating mechanism 11 and the accumulator 9.

Holes 21 and 22 are formed in the center of the diaphragm 2 and the center of the power piston 3, respectively.
Airtightly insert the power piston 3 into the valve body 23
Large diameter cylinder (hereinafter referred to as valve body large diameter cylinder) 24
Is attached.

The valve body 23 includes a valve body large-diameter cylindrical portion 24 having a large-diameter hole 25 with a bottom, and the valve body large-diameter cylindrical portion.
A valve body small-diameter cylindrical portion 26 connected to 24 is generally configured. The tip side of the small-diameter tubular portion 26 of the valve body (the other end side)
Protrudes to the outside of the casing 8 through a hole 27 formed in the rear surface of the housing 1 and a hole 28 formed in the casing 8 in a secret manner, and the atmosphere is introduced into the inside through an opening 29 of the small-diameter cylindrical portion 26 of the valve body. It can be done. In the valve body small-diameter tubular portion 26, first, second, third, fourth, and fifth hole portions 30, 31, whose inner diameters decrease in order from the opening 29 toward the valve body large-diameter tubular portion 24, 32, 33, 34 are formed, and the fifth hole portion 34 communicates with the large diameter hole 25. First, second, third, fourth and fifth holes
First, second, third, and fourth step portions 35, 36, 37, 38 are formed between 30, 31, 32, 33, 34, respectively. Third
An annular protrusion 40 that protrudes toward the input shaft 39 is formed on the inner diameter side portion of the step portion 37.

The large diameter hole 25 of the valve body 23 accommodates a reaction disk 41 and a large diameter end portion 43 of the output shaft 42 connected to a master cylinder (not shown). Contains a plunger 44 which is linked to the input shaft 39. The plunger 44 is a first plunger 45 located in the first, second and third hole portions 30, 31, 32.
And a second plunger 46 slidably accommodated in the fifth hole 34.

The first plunger 45 is slidably housed in the third hole 32 through a pair of seal members 47, 47.
A plunger main body 48, a first plunger shaft portion 49 connected to the first plunger main body 48 and extending toward the opening 29,
The second plunger 46 is provided so as to be connected to the plunger body 48.
The first, second, and third small diameter portions 50, 51, 52 of which the diameter is gradually reduced toward the first side, and the first of the first plunger shaft portion 49 is
The first plunger flange portion 53, which is located on the side of the plunger main body 48 and projects outward in the radial direction, is roughly configured. The first plunger shaft portion 49 is connected to the input shaft 39, and the input shaft 39 is adapted to be linked to the movement of a brake pedal (not shown).

The second plunger 46 is the second plunger body.
54 and the second plunger shaft portion connected to the first plunger 45
55 and a second plunger flange portion 56 formed on the second plunger body 54 so as to project radially outward. The first plunger 45 and the second plunger 46 are the central passages in which the second plunger shaft portion 55 is formed in the first plunger 45.
It is pressed into 57 and integrated.

The central passage 57 extends to the first plunger body 48. One end side is connected to the extension of the central passage 57 and the other end side is the first plunger flange portion 53 of the first plunger 45.
The plunger first communication passage 58 is opened to the outside at the front side of the
Are formed. Further, one end of the central passage 57 is opened and the other end thereof is opened to the outside of the plunger first small-diameter portion 50 to form a second plunger communication passage 59. An annular groove 60 is provided between the pair of seal members 47 of the first plunger body 48.
Are formed. One end side is open to the annular groove 60, and the other end side is a plunger second small diameter portion 51 and a plunger third small diameter portion 52.
A plunger third communication passage 61 is formed in the step portion between and.

The valve body 23 has a vacuum passage 6 having one end opening to the constant pressure chamber 4 and the other end opening to the second step 36.
2, a variable pressure chamber communication passage 63 whose one end side is opened to the variable pressure chamber 5 and the other end side is opened to the fourth hole 33, and a pressure accumulation which one end is opened to the pressure accumulation chamber 9 and the other end is opened to the third hole 32 A chamber communication passage 64 is formed. Accumulation chamber communication passage 64 and the first plunger
A stopper 65 is provided by being inserted into the annular groove 60 of 45.

A ring-shaped retainer 66 which is fitted to the first plunger shaft portion 49 is fitted and inserted in the first hole portion 30 of the valve body 23. A retainer seal member 67 is interposed between the first plunger shaft portion 49 and the retainer 66. A small diameter first retainer hole 68 and a large diameter second retainer hole 69 communicating with the first retainer hole 68 are provided in the retainer 66 from the opening 29 side of the retainer 66 toward the second retainer hole 69 side. Is formed. The check valve valve body 70 is accommodated in the second retainer hole 69 so as to be movable in the axial direction facing the first retainer hole 68, and the second retainer hole 69 is provided from the opening 29 side.
The check valve valve body 70 separates from the first retainer hole 68 to allow the flow of atmospheric air to the side, while the check valve valve body 70 does not allow the flow in the opposite direction. Seals the first retainer hole 68 to suppress the flow. In the present embodiment, the check valve 71 is composed of the first retainer hole 68, the second retainer hole 69, the check valve valve body 70, etc. described above.

A first control valve mechanism 72 as an opening / closing valve is arranged so as to be located between the retainer 66 and the second step portion 36. The first control valve mechanism 72 has a flexible tubular first control valve mechanism valve body 73. The valve body 73 for the first control valve mechanism has its base portion sandwiched and held between the retainer small-diameter portion 74 provided on the distal end side of the retainer 66 and the first step portion 35.

The tip portion of the first control valve mechanism valve body 73 is the second
Of the first control valve mechanism valve body 73 and the second step portion 36 to form a vacuum valve 75. Of the control valve mechanism valve body 73 and the first plunger flange portion 53 of the first
It constitutes the atmospheric valve 76 of. First control valve mechanism valve body 73
A rigid member 77 is mounted on the tip side of the valve, and a spring 78 is interposed between the rigid member 77 and the retainer 66 to output the tip side of the first control valve mechanism valve body 73. It is biased toward the shaft 42 side.

A second control valve mechanism (compressed air valve) 79 is provided on the output shaft 42 side portion of the second plunger 46 inside the valve body 23. The second control valve mechanism 79 has a second
It has a control valve mechanism valve body 80. The base portion of the second valve element 80 for the control valve mechanism is held by the second small diameter portion 51 of the plunger, and the valve flange 81 extending radially inward is provided on the tip side.
Are formed.

The tip of the second valve body 80 for the control valve mechanism is adapted to be separated from and seated on the third step portion 37 and the second plunger flange portion 56, and the valve for the second control valve mechanism is The body 80 and the third step 37 constitute a second atmosphere valve 82, and
Control valve mechanism valve body 80 and second plunger flange portion 56
To constitute a compressed air valve 83.

A rigid member 84 is mounted on the tip side of the second valve body 80 for the control valve mechanism, and the rigid member 84 and the retainer are attached.
A spring 85 is interposed between the first control valve mechanism valve 66 and the second control valve mechanism 66, and urges the tip end side of the second control valve mechanism valve body 80 toward the output shaft 42 side.

In the figure, 86 is a valve body return spring interposed between the front surface of the housing 1 and the valve body 23, and 87 is an input interposed between the step portion of the input shaft 39 and the retainer 66. It is a return spring for the shaft.

The operation of the pneumatic booster thus constructed will be described. When the brake 44 is operated to move the plunger 44 forward through the input shaft 39 during normal braking at the normal deceleration, the first plunger flange portion 53 separates from the first control mechanism valve body 73 and the first atmospheric valve 76. Opens. As a result, the check valve 71, the first atmosphere valve 76, the plunger first communication passage 58,
Central passage 57, plunger second communication passage 59, second atmospheric valve
82, the atmosphere is introduced into the variable pressure chamber 5 through the variable pressure chamber connecting passage 63. Then, a differential pressure is generated between the constant pressure chamber 4 and the variable pressure chamber 5, and the differential pressure causes the power piston 3 to move forward to move the output shaft.
A large thrust is applied to 42 to generate a braking force via a master cylinder (not shown) connected to the output shaft 42.

During high deceleration braking or sudden braking, the input shaft
39 is further pushed, the plunger 44 is further advanced, the valve flange 81 of the second atmosphere valve 82 is seated on the third step portion 37, and the second
The atmospheric valve 82 is closed, the valve flange 81 is supported by the third step portion 37, and the plunger 44 is moved forward to open the compressed air valve 83. Therefore, the compressed air stored in the pressure accumulating chamber 9 flows into the variable pressure chamber 5 through the pressure accumulating chamber communication passage 64, the annular groove 60, the third plunger communication passage 61, the compressed air valve 83 and the variable pressure chamber communication passage 63. To do. Then, the constant pressure chamber 4 and the variable pressure chamber 5
A large differential pressure is generated between the pressure difference and the pressure when the atmosphere is introduced into the variable pressure chamber 5, and the large differential pressure causes the power piston 3 to move forward to apply a larger thrust to the output shaft 42. , A braking force is generated via a master cylinder (not shown) connected to the output shaft 42.

An annular protrusion 40 protruding toward the input shaft 39 is formed on the inner diameter side portion of the third step portion 37, and the third step portion 37 and the second step portion 37 are formed through the annular protrusion 40. Control valve mechanism valve body 80
And are closely contacted with each other with high accuracy, and when compressed air is introduced into the variable pressure chamber 5, it is ensured that compressed air is sent to the first control valve mechanism 72 via the second atmosphere valve 82 and the central passage 57. To prevent.

When the brake pedal is returned after the above state, the input shaft 39 and the plunger 44 are moved to the valve body 23 by the elastic force of the input shaft return spring 87, the valve body return spring 86 and the reaction disc 41.
With respect to the vacuum valve 75, the tip end side of the first control mechanism valve body 73 is pushed by the first plunger flange portion 53, is separated from the third step portion 37, and the vacuum valve 75 is opened. Further, the second control valve mechanism 79 is returned as shown in FIG. 1 so that the compressed air valve 83 is closed and the second atmosphere valve 82 is opened.

The compressed air and the atmosphere flowing into the variable pressure chamber 5 are connected to the variable pressure chamber communication passage 63, the second atmosphere valve 82, the plunger second communication passage 59, the central passage 57, and the plunger first communication passage.
It is discharged to the vacuum source 7 of the engine through 58, the vacuum valve 75, the vacuum passage 62 and the constant pressure chamber 4. At this time, the first control valve mechanism valve body 73 is temporarily bent inward by the pressure of the compressed air, and
Even if the atmospheric valve 76 is opened, since the check valve 71 is formed on the opening 29 side, the compressed air can be suppressed from being discharged to the outside from the opening 29. Therefore, noise caused by discharging the compressed air through the compressed air opening 29 is not generated.

In this embodiment, the pneumatic device is composed of the compressed air generating mechanism 11 and the pressure accumulating chamber 9 and the like, but instead of this, a compressed air storage tank replacing the pressure accumulating chamber 9 is provided separately from the housing 1. At the same time, the compressed air storage tank and the variable pressure chamber 5 are connected via a compressed air valve 83, and the compressed air valve
The pneumatic device may be configured such that the opening / closing operation of 83 is interlocked with the input shaft 39.

The check valve 71 may be constructed as shown in FIG. 2, for example. That is, in the figure, the retainer 66
A hole 90 having a constant inner diameter extending in the axial direction is formed in this.
A ring-shaped disc 91 made of rubber is located on the output shaft 42 side of the retainer 66 so as to close the hole 90. In the example of FIG. 2, the air flow from the hole 90 to the disk 91 side is allowed, while the disk 91 closes the hole 90 against the fluid flow in the opposite direction. To constitute a check valve 71. With this check valve 71,
The structure is simpler than that shown in FIG. 1, the number of parts is small, and high processing accuracy is not required. Therefore, the check valve 71 can be reduced in cost, and by using the check valve 71, the pneumatic booster can be reduced in cost.

A second control valve mechanism 79 shown in FIG. 3 may be provided instead of the second control valve mechanism 79 of FIG. In the third step portion 37 in FIG. 3, the third step portion 37 shown in FIG.
In contrast to the structure in which the annular protrusion 40 is provided, the annular protrusion 40 is omitted.

The pneumatic booster of FIG. 3 using the second control valve mechanism 79 is different from that of FIG. 1 in that the annular projection 40 is omitted in the third step portion 37. The precision of contact between the third step portion 37 and the second control valve mechanism valve body 80 is reduced, and the variable pressure chamber 5
When the compressed air is introduced into the second atmosphere valve 82 and the central passage 57
Although compressed air may be sent to the first control valve mechanism 72 via the above, since the check valve 71 is provided in the opening 29 side portion of the first control valve mechanism 72 as described above, It is possible to prevent the compressed air from being discharged through the opening 29 and causing noise. Therefore, by omitting the formation of the annular projection 40 on the third step portion 37, the shape can be simplified,
The processing accuracy can be relaxed, and the overall cost of the device can be reduced.

[0034]

Since the present invention is the pneumatic booster configured as described above, when the brake pedal is suddenly returned after the internal pressure of the variable pressure chamber is set to the compressed air pressure, the compressed air is compressed. Even if the on-off valve is pushed open due to the pressure difference between the air pressure and the atmospheric pressure and compressed air passes through the on-off valve, the check valve suppresses the flow of this compressed air, so the compressed air is discharged to the outside from the opening. Noise can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing a pneumatic booster according to an embodiment of the present invention.

2 is a cross-sectional view showing a pneumatic booster using another check valve in place of the check valve of FIG.

3 is a cross-sectional view showing a pneumatic booster using a second control valve mechanism that replaces the second control valve mechanism of FIG.

[Explanation of symbols]

 1 Housing 2 Diaphragm 3 Power Piston 4 Constant Pressure Chamber 23 Valve Body 27 Hole on Rear of Housing 1 39 Input Shaft 44 Plunger 71 Check Valve 72 1st Control Valve Mechanism 73 1st Control Valve Mechanism Valve Body 75 Vacuum Valve 76 First atmosphere valve 79 Second control valve mechanism 82 Second atmosphere valve 83 Compressed air valve

Claims (1)

[Claims] 1. A constant pressure chamber and a variable pressure chamber are defined by a power piston provided with a diaphragm inside the housing, and one end side of a substantially cylindrical valve body is airtightly attached to the power piston, and A plunger that is airtightly passed through a hole formed on the rear surface of the housing and protrudes outside the housing to communicate the inside of the valve body with the atmosphere and interlocks with the input shaft in the valve body, and the input shaft, the plunger and the valve. An on-off valve that opens and closes according to the relative displacement of the body is provided, and a pneumatic device is connected to the variable pressure chamber via a compressed air valve that opens and closes in response to the input shaft, and the valve body is opened and closed by opening and closing the open-close valve. The communication between the constant pressure chamber and the variable pressure chamber through the formed vacuum passage and the disconnection, and the variable pressure chamber and the atmosphere through the internal space of the valve body and the atmosphere passage formed in the valve body Pneumatic booster that sets and switches the internal pressure of the variable pressure chamber to vacuum pressure, atmospheric pressure or compressed air pressure by supplying compressed air from the pneumatic device to the variable pressure chamber in response to the opening and closing of the compressed air valve. The pneumatic booster is characterized in that a check valve that allows only the inflow of air into the valve body is provided on the side of the atmosphere opening inside the valve body.