JP2902844B2 - Pneumatic booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic booster for assisting the operation of a master cylinder in a vehicle or the like in response to a brake operation or the like.

[0002]

2. Description of the Related Art Conventionally, a housing having a front shell and a rear shell, a power piston which is slidably inserted in a generally bottomed cylindrical valve body into an insertion hole provided in a rear shell of the housing, A valve plunger inserted into a valve plunger chamber provided at the bottom of the valve body of the power piston, an operating rod connected to the valve plunger and operated in response to a brake pedal input, and an inner peripheral side supported by the power piston. And a diaphragm whose outer peripheral portion is supported by the housing and partitions the inside of the housing into a negative pressure chamber on the front shell side and a working pressure chamber on the rear shell side; and a working pressure chamber and a negative pressure chamber provided in the valve body. A valve mechanism for communicating and shutting off, and for communicating and shutting off the working pressure chamber and the atmosphere; A pneumatic booster composed of a seat surface provided on a valve plunger, a seat surface provided on a valve body portion, and a valve member which is detachably seated on the seat surface is disclosed in Japanese Utility Model Laid-Open No. 2-99061. There is one disclosed in the official gazette, and the configuration inside the valve body of the power piston of this pneumatic booster is as shown in FIG.

That is, a retainer 81 fitted into the inner peripheral portion of a substantially bottomed cylindrical valve body portion 80, and an outer bead portion 82 and a valve body portion 80 attached to a left side surface of the retainer 81 in FIG. The second communication hole 84 and the valve plunger chamber 85 contact or separate from the bottom 83.
A valve portion 88 that controls the communication with the valve plunger 86 and controls the communication between the first communication hole 87 and the atmosphere by contacting or separating from the valve plunger 86, and connects the valve portion 88 with the outer peripheral bead portion 82. A valve 91 or the like made of an elastic member having a rolling portion 90 that can expand and contract according to the operation of the operating rod 89 and the like is provided, and the negative pressure applied to the valve 91 is reduced by extending the retainer 81 inward. The effect of the thrust in the axial direction (left-right direction in FIG. 3) of the pressure difference from the atmospheric pressure is reduced.

[0004]

However, in the above-mentioned pneumatic booster, the valve 91 is displaced in the radial direction due to the influence of the differential pressure applied to the rolling portion 90 of the valve 91 other than the axial direction. And the valve 91
There is a possibility that the seating position of the valve portion 88 may be shifted to cause poor airtightness.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pneumatic booster having high airtight reliability without causing a deviation in a seating position of a valve.

[0006]

In order to achieve the above object, a pneumatic booster according to the present invention comprises a housing having a front shell and a rear shell, and a fitting hole provided in the rear shell of the housing. A power piston slidably fitted in a substantially bottomed cylindrical valve body, a valve plunger inserted into a valve plunger chamber provided at the bottom of the valve body of the power piston, and connected to the valve plunger An operating rod that is operated in response to an input from a brake pedal, an inner peripheral side is supported by the power piston, and an outer peripheral part is supported by the housing. A diaphragm partitioned into a working pressure chamber; and a diaphragm provided in the valve body, wherein the working pressure chamber and the negative A chamber communicated with and blocking, and a valve mechanism for communicating and blocking the said working pressure chamber and the atmosphere,
The valve mechanism includes a seat surface provided on the valve plunger, a seat surface provided on the valve body portion, and a valve member which is separated from and seated on the seat surface, and one end side is provided with the valve member. A retainer fixed to the inner peripheral portion of the valve body portion and having the other end side as a cylindrical portion slidingly guiding the valve member on the outer peripheral surface is provided, and the valve member is biased toward the valve plunger chamber. It is characterized by becoming.

[0007]

According to the pneumatic booster of the present invention, a retainer having one end fixed to the inner peripheral portion of the valve body and the other end formed as a cylindrical portion for slidingly guiding the valve member on the outer peripheral surface is provided. , Biasing the valve member toward the valve plunger chamber,
The valve member is detached from and seated on a seat surface provided on the valve plunger and a seat surface provided on the valve body, thereby communicating and blocking the working pressure chamber and the negative pressure chamber.
The working pressure chamber and the atmosphere are communicated and shut off. Then, a differential pressure between the negative pressure and the atmospheric pressure is applied to the retainer. However, since the retainer does not deform due to the influence of the differential pressure or the like, the retainer slides along the outer peripheral surface of the cylindrical portion of the retainer. The valve member does not shift in the radial direction.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A pneumatic booster according to one embodiment of the present invention will be described below with reference to FIGS. In the following description, up, down, left, and right are used for convenience.

In the drawing, reference numeral 1 denotes a pneumatic booster, reference numeral 2 denotes a front shell in which a master cylinder (not shown) is provided on a left side surface portion 3, and reference numeral 4 denotes a front shell fitted to the right side of the front shell 2. 2 is a rear shell forming a housing 5 together with a power piston 6 slidably supported by the housing 5 in the left and right direction;
The output shaft 9 has a right end and a left end protruding from an insertion hole 8 provided in the front shell 2 and outputs leftward toward a master cylinder (not shown) by moving the power piston 6 leftward. A front seal 10 seals between the front shell 7 and the insertion hole 8 of the front shell 2. Reference numeral 10 denotes a left end 10 a abuts against the inner wall 11 of the front shell 2 and a right end 10 b denotes a left end face 12 of the power piston 6.
And a return spring 13 for urging the power piston 6 rightward with a predetermined urging force. A bead-shaped inner peripheral portion 14 is fitted to the power piston 6 and an outer peripheral portion 15 is supported by the housing 5. Each of the diaphragms is shown.

The inside of the housing 5 is communicated from the negative pressure communication pipe 16 to a negative pressure source (not shown) by the diaphragm 13, and a negative pressure chamber 17 on the front shell 2 side, which is always in a negative pressure state, is not shown. The operating pressure chamber 19 on the side of the rear shell 4 from which the air is introduced or the introduced air is discharged according to the operation of the operating rod 18 which moves in the left-right direction by operating the brake pedal.

The power piston 6 has a tubular portion 20 formed to protrude from the rear shell 4 and extending in the left-right direction. The power piston 6 is provided on the left side of the tubular portion 20 and is housed in the housing 5. A flange portion 21 having a predetermined diameter larger than that of the portion 20
And a valve body 22 having a substantially cylindrical shape with a bottom provided therein with a valve mechanism 22 for controlling the introduction and discharge of the atmosphere of the working pressure chamber 19, and an outer peripheral portion of a flange 21 of the valve body portion 23. The negative pressure chamber 17 and the working pressure chamber 19 are provided to extend outward.
And a piston portion 24 that receives a pressure difference between The cylindrical portion 20 of the valve body 23 is slidably fitted into and supported by the fitting hole 25a of the rear seal and support member 25 supported on the inner periphery of the right end of the rear shell 4, and the rear shell 4, the diaphragm 13, The working pressure chamber 19 is surrounded by a valve body portion 23, a rear seal and support member 25, and the like.
Is composed.

The front end of the cylindrical portion 20 of the valve body 23 of the power piston 6 and the rear shell 4 are connected by an elastically deformable boot 26. The boot 26 allows the valve body 23 and the rear seal and support member 25 to be connected. , Dust and the like are prevented from adhering to the gap. Further, in the right side portion of the cylindrical portion 20 of the valve body portion 23, dirt, dust, and the like are contained in the valve body portion 23.
There is provided a filter 27 for preventing intrusion into the inside.

An inner peripheral portion of the cylindrical portion 20 of the valve body portion 23 has a large-diameter inner peripheral portion 30 having a predetermined diameter provided from a right end thereof to a predetermined position and a left-hand side of the large-diameter inner peripheral portion 30. A small-diameter inner peripheral portion 31 having a smaller diameter than the large-diameter inner peripheral portion 30 by a predetermined amount;
A bottom portion 32 on the left side of the small-diameter inner peripheral portion 31, and a stepped portion extending along a direction perpendicular to the axis of the valve body portion 23 at a boundary between the large-diameter inner peripheral portion 30 and the small-diameter inner peripheral portion 31. The part 33 is formed over the circumferential direction. In the vicinity of the bottom portion 32 at the left end portion of the small diameter inner peripheral portion 31 of the valve body portion 23, a second communication hole 34 opened near the bottom portion 32 and penetrating through the valve body portion 23 and communicating with the negative pressure chamber 17. Further, a valve plunger chamber 3 having a smaller diameter than the small diameter inner peripheral portion 31 by a predetermined amount is provided on a bottom portion 32 inside the second communication hole 34.
5 are provided. Then, the bottom 3 near the boundary between the valve plunger chamber 35 and the small-diameter inner peripheral portion 31 is thereby formed.
2, a first seat surface (seat surface provided on the valve body portion) 36 is formed along a direction orthogonal to the axial direction of the valve body portion 23.

The valve plunger chamber 35 of the valve body 23 is provided with a valve plunger insertion hole 37 having a predetermined diameter and a predetermined depth in a direction along the axis of the valve body 23 on the left side thereof. A valve plunger 38 is slidably inserted into the plunger insertion hole 37. On the other hand, the valve body portion 23 is provided with a first series of through holes 39 from the opening of the valve plunger insertion hole 37 of the valve plunger chamber 35 in a direction orthogonal to the axis of the valve body portion 23. Through the through hole 39, the valve plunger chamber 35 and the working pressure chamber 19 are in communication. Further, on the left side of the valve plunger insertion hole 37 of the valve body portion 23, a reaction disk 40 as a pressure deformable member and a reaction disk insertion hole 42 of a predetermined diameter into which a right end insertion portion 41 of the output shaft 7 is inserted are provided. Have been.

Here, the valve plunger 38 includes:
A groove 43 is provided at a predetermined position on the outer peripheral portion, and a spherical portion 44 of the operating rod 18 is provided on the right side thereof.
Are connected to each other, and a convex portion 46 for preventing the spherical portion 44 of the operating rod 18 from being pulled out is provided in the operating rod connecting hole 45. A seat portion 47 extending rightward by a predetermined length is provided outside the operating rod connection hole 45, and a right end portion of the seat portion 47 has a second seat surface (a seat provided on the valve plunger). Plane) 48.

The operating rod 18
Is a first shaft portion 49 having a predetermined diameter on the right side, and the first shaft portion 49 provided at a predetermined position on the left side of the first shaft portion 49 with a predetermined width.
A flange portion 50 having a larger diameter by a predetermined amount; a second shaft portion 51 having a predetermined length provided on the left side of the flange portion 50 and having substantially the same diameter as the first shaft portion 49; A third shaft portion 52 provided at a predetermined length further to the left and having a smaller diameter by a predetermined amount than the second shaft portion 51,
The spherical portion 44 is provided on the left side of the third shaft portion 52. One end of a first spring 53, which will be described later, comes into contact with a boundary between the flange 50 and the second shaft 51.

The first communication hole 3 of the valve body 23
A plate 54 is inserted into the groove 9 with a predetermined width gap, and the upper end of the plate 54 is inserted into the groove 43 of the valve plunger 38 with a predetermined width gap. Further, the lower end portion thereof can be brought into contact with a stopper 55 mounted in the rear shell 4 so that movement of the lower end portion beyond a predetermined position in the right direction is restricted. The plate 54 regulates a limit position of the right movement of the power piston 6 and regulates a positional relationship between the power piston 6 and the valve plunger 38.

In the space between the valve body 23 and the operating rod 18, a retainer 56, a valve member 57, a first spring 53 and a second spring 5 are provided.
8 etc. are provided. Next, these are mainly shown in FIG.
This will be described with reference to FIG. The above-described valve mechanism 22 includes a valve member 57, a first seat surface 36, and a second seat surface 48.

The retainer 56 has substantially the same diameter as the large-diameter inner peripheral portion 30 of the valve body 23 provided at one end thereof, and has a predetermined length along the axial direction (left-right direction in the figure) of the valve body 23. A first cylindrical portion 59 having a length, and a first perforated disk portion 6 extending radially inward from a left end of the first cylindrical portion 59
0, a second cylindrical portion 61 extending a predetermined length from the inside of the first perforated disk portion 60 to the left in the axial direction and having a smaller diameter than the small diameter inner peripheral portion 31 by a predetermined amount; A second perforated disk portion 62 extending radially inward from the left end of the second perforated disk portion;
A third cylindrical portion 63 extending a predetermined length to the left in the axial direction from the inside of the third cylindrical portion 63 having a smaller diameter than the second cylindrical portion 6 by a predetermined amount, and a third cylindrical portion 63 extending radially inward from the left end of the third cylindrical portion 63. Three perforated disk portions 64,
The third shaft portion 5 of the operating rod 18 provided inside extends from the inside of the third perforated disk portion 64 leftward in the axial direction (toward the valve plunger chamber 35) by a predetermined length.
It is an integrally molded product having a fourth cylindrical portion 65 on the other end side having a predetermined diameter larger than that of the second cylindrical portion 65. And, the first cylindrical portion 5 of the retainer 56
A seal member 66 is fitted in a portion surrounded by the first perforated disk portion 9, the second perforated disk portion 60, the second cylindrical portion 61, and the step portion 33 of the valve body portion 23, and the outer periphery of the retainer 56 is fitted by the seal member 66. The communication between the side and the inner peripheral side of the valve body portion 23 is blocked. Here, the first cylindrical portion 59, the first perforated disk portion 60, the second cylindrical portion 61, the second perforated disk portion 62,
The third cylindrical portion 63 and the third perforated disk portion 64 are
7. Note that the fourth cylindrical portion 65 constitutes a cylindrical portion in the present embodiment.

The boundary between the second cylindrical portion 61 and the second perforated disk portion 62 of the retainer 56 and the boundary between the flange portion 50 and the second shaft portion 51 of the operating rod 18 are provided. A first spring 53 having a predetermined urging force is provided. The operating rod 18 is urged rightward by the first spring 53, and the second seat surface 48 of the valve plunger 38 to which the operating rod 18 is connected abuts on the third seat surface 68 of the valve member 57. The atmosphere valve constituted by these is closed (described later).

The valve member 57 includes a main body 69 having a left seat surface provided with a third seat surface 68 which can be detachably seated on the first seat surface 36 of the valve body 23 and the second seat surface 48 of the valve plunger 38. The fourth cylindrical portion 65 of the retainer 56, which is bent and protrudes from the right inner side of the main body 69.
A valve body 71 made of an elastic material having a lip portion 70 slidably guided while maintaining airtightness, and a reinforcing cup 72 fixed to the right surface of the valve body 71. Second perforated disk portion 6 of cup 72 and retainer 56
A second spring 58 having a predetermined urging force is provided between the second and third cylindrical portions 63 to urge the valve member 57 toward the valve plunger chamber 35. The second spring 58 has a biasing force or the like set so that the valve member 57 follows the movement of the valve plunger 38, similarly to the rolling portion of a conventional valve.

Here, when the third seat surface 68 of the valve member 57 is separated from and seated on the first seat surface 36 of the valve body 23, the working pressure chamber 19 and the negative pressure chamber 17 are communicated and shut off. When the three seat surfaces 68 are separated from and seated on the second seat surface 48 of the valve plunger 38, the working pressure chamber 19 and the atmosphere are communicated and shut off. Note that a valve composed of the third seat surface 68 and the first seat surface 36 is called a vacuum valve, and a valve composed of the third seat surface 68 and the second seat surface 48 is called an atmospheric valve.

According to the pneumatic booster 1 configured as described above, the normal state (the state where the brake pedal is not depressed)
, The valve member 57 causes the third seat surface 68 to contact the first seat surface 36 and the second seat surface 48 by the urging force of the second spring 58 to close the vacuum valve and the atmospheric valve, and the negative pressure chamber 17 The communication between the pressure chamber 19 and the working pressure chamber 19 via the second communication hole 34, the valve plunger chamber 35 and the first communication hole 39 is cut off, and the valve plunger chamber 35 and the first communication path between the operating pressure chamber 19 and the atmosphere are interrupted. When the brake pedal is depressed and the valve plunger 38 moves to the left with respect to the valve body 23 via the operating rod 18, the second seat surface 48 is closed. And the third seat surface 68 of the valve member 57 are separated from each other, and the atmospheric valve is opened. Then, the air is introduced, and the power piston 6 moves to the left so that the output shaft 7 protrudes due to the pressure difference from the negative pressure chamber 17, the boost operation is performed, and the depression of the brake pedal is released. And the operating rod 18 and the valve plunger 38 move rightward with respect to the power piston 6 to bring the second seat surface 48 into contact with the third seat surface 68 of the valve member 57 to close the atmospheric valve and further close the valve. The member 57 is pressed and moved against the urging force of the second spring 58 to separate the first sheet surface 36 and the third sheet surface 68 to open the vacuum valve, thereby opening the first communication hole 39 and the second communication hole. Conventional operations can be performed, such as communicating the working pressure chamber 19 and the negative pressure chamber 17 via 34 and the like to eliminate the pressure difference between them and return the power piston 6 to its original position.

When the vacuum valve constituted by the first seat surface 36 and the third seat surface 68 is closed, the differential pressure between the negative pressure and the atmospheric pressure is always applied to the retainer 56. The retainer 56 of this embodiment is not deformed by the influence of the differential pressure or the like.
The valve member 57 that slides along the outer peripheral surface of the fourth cylindrical portion 65 of No. 6
No displacement occurs in the radial direction. Therefore,
Since the seating position of the valve member 57 does not shift, the airtight reliability of this portion can be improved. In addition, as the material of the retainer 56, for example, a synthetic resin, a metal, or the like having a strength not deformed by the differential pressure can be adopted.

[0025]

As described above in detail, according to the pneumatic booster of the present invention, the differential pressure between the negative pressure and the atmospheric pressure is applied to the retainer. Since the valve member does not deform due to the influence, the valve member that slides along the outer peripheral surface of the cylindrical portion of the retainer does not shift in the radial direction. Therefore, since the seating position of the valve member does not shift, airtight reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pneumatic booster according to an embodiment of the present invention, showing a normal state (a state in which an operating rod is not operated).

FIG. 2 is a cross-sectional view showing a main part in a valve body of the pneumatic booster according to one embodiment of the present invention, showing a normal state (a state in which an operating rod is not operated).

FIG. 3 is a cross-sectional view showing a main part of a valve body in a conventional pneumatic booster, showing a normal state (a state in which an operating rod is not operated).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pneumatic booster 2 Front shell 4 Rear shell 5 Housing 6 Power piston 13 Diaphragm 17 Negative pressure chamber 18 Operating rod 19 Operating pressure chamber 22 Valve mechanism 23 Valve body part 25a Fitting hole 32 Bottom part 36 First seat surface (valve body) 35) Valve plunger chamber 38 Valve plunger 48 Second seat surface (seat surface provided in valve plunger) 56 Retainer 57 Valve member 65 Fourth cylindrical portion (cylindrical portion)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-3566 (JP, A) JP-A-64-109159 (JP, A) JP-A-63-71470 (JP, A) JP-A 61-61 244657 (JP, A) JP-A-62-258852 (JP, A) JP-A-62-80150 (JP, A) JP-A-62-80149 (JP, A) JP-A-5-503478 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60T 13/52-13/577

Claims (1)

(57) [Claims] 1. A housing having a front shell and a rear shell, a power piston slidably fitted into a fitting hole provided in the rear shell of the housing in a substantially bottomed cylindrical valve body portion, A valve plunger inserted into a valve plunger chamber provided at the bottom of the valve body of the power piston, an operating rod connected to the valve plunger and operated in response to an input of a brake pedal, and an inner peripheral side supported by the power piston A diaphragm whose outer peripheral portion is supported by the housing and partitions the inside of the housing into a negative pressure chamber on the front shell side and a working pressure chamber on the rear shell side; and a working pressure chamber provided in the valve body portion. To and from the negative pressure chamber, and to and from the working pressure chamber and the atmosphere. The valve mechanism comprises a seat surface provided on the valve plunger, a seat surface provided on the valve body, and a valve member which is separated from and seated on the seat surface. In the pneumatic booster, a retainer having one end fixed to the inner peripheral portion of the valve body portion and the other end portion being a cylindrical portion that slides and guides the valve member on the outer peripheral surface is provided, A pneumatic booster characterized by being urged toward the valve plunger chamber.