JPH04314663A - Discharge valve structure for liquid pressure type booster - Google Patents

Abstract

PURPOSE:To prevent a flutter noise generated from a discharge valve, when a brake is loosened, by providing a crossing wall surface part, crossed in a tapered part, before and after the tapered part of a seat member serving as a valve seat of the discharge valve. CONSTITUTION:A bottom wall part 200 and a tubular part 300, crossing with a tapered part 161, are provided before and after a seal point S of a discharge valve Vo. A wall surface of the bottom wall part 200 in the bottom of a recessed part 110 is orthogonal to an axial line of a movable valve 44 to set a distance from the movable valve unit 44 when the discharge valve Vo is closed to about 0.2 to 0.3mm. The tubular part 300 in an opening side of the recessed part 110 is extended in parallel to the axial line so as to surround the side periphery of the movable valve unit 44, and also a distance between an internal wall surface of the tubular part 300 and a side wall of the movable valve unit 44 is set to about 0.2 to 0.3mm. Thus by providing a throttle part, even in the case of liquid from a side of a servo chamber 38 flowing out to a side of a passage 60 through the discharge valve Vo changed from closing to opening when a brake is loosened, a flutter noise of squeak is prevented from being generated.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a hydraulic booster used in a brake system of a vehicle etc. to assist the operation of a master cylinder. This relates to the structure of a discharge valve for communicating and blocking.

0002

[Prior Art and its Problems] This type of hydraulic booster has a servo piston inside the cylinder body, and a servo chamber at one end, as shown in, for example, Japanese Patent Laid-Open No. 63-287656. It is divided. Inside the servo piston there is also a valve chamber in which the supply and discharge valves are arranged. The supply valve is a valve for communicating and shutting off between the servo chamber and an external source of hydraulic pressure, while the discharge valve is a valve for disconnecting and communicating between the servo chamber and an external source of hydraulic pressure release. It is the valve of The two valves are typically arranged around a movable valve body that fits into a servo piston. The movable valve body has a hollow structure with a passage inside, and the passage is used as a communication path to a source of hydraulic pressure release. Therefore, the supply valve is located in the middle of the movable valve body, whereas the discharge valve is located at one end of the movable valve body. That is, one end of the movable valve body faces the recessed portion of the seat member, and functions as a discharge valve by coming into contact with and leaving the tapered portion within the recessed portion.

By the way, when such a hydraulic booster operates, the pressure inside the valve chamber is high, while the inside of the passage of the movable valve body is under low pressure (atmospheric pressure). Therefore, when the discharge valve changes from closed to open due to the loosening operation, the liquid from the servo chamber side passes through the recess in the seat member at a high flow velocity and is discharged toward the passage inside the movable valve body. That will happen. Is that why?
It was found that a squealing sound was produced when the product was first loosened, which could cause discomfort to drivers and the like.

0004

[Object of the Invention] An object of the present invention is to solve the above-mentioned noise problem by devising the structure of the discharge valve portion of a hydraulic booster, particularly the shape of the seat member that constitutes the valve seat. It is in.

[0005]

[Means and Effects Therefor] In the present invention, within the recessed portion of the seat member, at least one of the front and rear sides of the tapered portion on which the end edge of one end surface of the movable valve body is seated has a cross wall surface that intersects with the tapered portion. I am trying to set it up. The intersecting wall portion may be either the bottom wall portion located at the bottom of the recess and facing one end surface of the movable valve body, or the cylindrical portion located on the opening side of the recess and surrounding the side periphery of the movable valve body. can also be applied. Of course, it is more preferable to apply both the bottom wall part and the side peripheral part. The intersecting wall portion should be close to the movable valve body (for example, 0.5 mm or less, more preferably 0.5 mm or less).
2 to 0.3 mm), so that the passage formed between the movable valve body and the movable valve body functions as a throttle for the liquid flowing from the servo chamber side to the hydraulic pressure release source side. Perhaps due to the effect of this throttle or because the flow becomes more complicated, the above-mentioned squeal no longer occurs.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic booster 10 has a cylinder body 14 having a stepped cylinder hole 12 therein. In this booster 10, an operating force is applied to the input member 16 from one side of the cylinder body 14 via a pedal or the like, and then a servo action occurs in response to the movement of the input member 16. The force assisted by this action is applied to the output member 18 on the other side of the cylinder body 14 through the servo piston 30 inside the cylinder hole 12, and is applied to the master cylinder side (not shown).

The servo piston 30 has a stepped hole or recess 32 open to the input member 16 side. Recess 32
The diameter is the largest on the opening side, and the diameter decreases in several steps toward the inside. Further, on the outer circumference of the servo piston 30, seal rings 34 and 36 are provided at locations separated from each other, thereby sealing the cylinder hole 12.
It is divided into multiple rooms. A portion adjacent to the lid member 20 that closes the opening of the cylinder hole 12 is a servo chamber 38,
The chamber around the servo piston 30 between the seal rings 34 and 36 is an inlet chamber 40, and the chamber around the output member 18 is a low pressure chamber 42. The low pressure chamber 42 is connected to a reservoir, which is a source of hydraulic pressure release, on the master cylinder side, and also connected to the inlet chamber 4.
0 are each connected to a hydraulic pressure source including an accumulator and a pump, also not shown.

When looking inside the recess 32 of the servo piston 30, there is an elongated cylindrical movable valve body 44 at the back of the recess 32. The movable valve body 44 is movable in the axial direction of the servo piston 30 while being supported by the end of the servo piston 30 and the support member 46 . The movable valve body 44 has a flange 45 in its midway portion, which receives a force from a spring 48 and is urged toward the input member 16 side. Therefore, the bulge 50 adjacent to the flange 45 is in contact with the opening 52 of the central hole 47 of the support member 46 . This bulge 5
0 and the opening 52 constitute the supply valve Vi. The supply valve Vi supplies hydraulic pressure from an external hydraulic pressure source to the servo chamber 38.
This is a valve for supplying Hydraulic pressure from the hydraulic pressure source first enters chamber 54 from inlet chamber 40 through passage 55 . The hydraulic pressure then passes from the open portion of the supply valve Vi to the chamber 90 around the movable valve body 44 and further to the support member 46.
It enters the relay chamber 92 in the large diameter part of the recess 32 through the diagonal passage 91 inside. Then, it enters the servo chamber 38 from the relay chamber 92 through the groove passage 93 on the outer periphery of the cylindrical member 58. The support member 46 and the cylindrical member 58 in the middle of the hydraulic pressure introduction path are connected to a threaded ring 5 screwed to the opening of the recess 32.
9, it is integrated with the servo piston 30. The cylindrical member 58 includes a passage 101 running in the radial direction connecting the groove passage 93 side on the outer periphery and the valve chamber 100 side on the inner periphery, as well as two passages connecting the relay chamber 92 and the reaction force chamber 70. There are two check valves 71 and 72 in the rear passage. One check valve 71 is a balance valve whose forward direction is from the reaction force chamber 70 around the input member 16 to the relay chamber 92, and the other check valve 72 is in the opposite direction to the balance valve 71. This is a jump-up valve with forward direction. The jump-up valve 72 functions to prevent hydraulic pressure from being introduced into the reaction chamber 70 until a predetermined pressure is reached, and the balance valve 71 functions to prevent hydraulic pressure from being introduced into the reaction chamber 70 until the hydraulic pressure in the servo chamber 38 is returned to the reservoir side. It functions to return hydraulic pressure to the reaction force chamber 70 when the pressure difference between the pressure chamber 38 and the reaction force chamber 70 reaches the opening pressure of the valve 71.

Now, while the supply valve Vi is located in the middle of the movable valve body 44, the discharge valve Vo is located at one end of the movable valve body 44. This is because, as mentioned above, the passage 60 inside the hollow movable valve body 44 is used as a part of the discharge path. The discharge valve Vo is a valve that controls communication and isolation between the servo chamber 38 side and the low pressure chamber 42 side. The movable valve body 44 passes through the support member 46, and its end portion 44e protrudes into the valve chamber 100. In the valve chamber 100, the tip of the input member 16 that receives an operation input is also located so as to face the end 44e of the movable valve body 44. The input member 16 includes three members 161 in the axial direction,
It is divided into 162 and 163. The protruding end 44e of the movable valve body 44 is connected to the first member 1 at the end of the input member 16.
I am facing the 61st. The first member 161 is the second member 16
The seal ring 61 is inserted into the hole at the end of the second member 162, and is urged toward the second member 162 by a spring 62. A tapered portion 161 whose diameter gradually increases toward the movable valve body 44 side is provided at the end of the first member 161.
There is a recess 110 having a shape t. The discharge valve Vo is configured with the tapered portion 161t in the recess 110 serving as a valve seat, and the edge of the end portion 44e of the movable valve body 44 serving as a valve portion. That is, the first member 161 of the input member 16 is connected to the discharge valve V
Functions as a seat member for o. In addition, the second member 1
62 and the third member 163 are integrally press-fitted with each other with the balance piston 120 built therein. The balance piston 120 is movable toward the operation input side, and when the servo piston 30 and the input member 16 approach each other during braking, the balance piston 120 alleviates the volume reduction of the reaction force chamber 70 and eliminates unnecessary internal pressure. This is to prevent the occurrence of

[0010] Here, attention will be paid to the recessed portion 110 of the first member 161, which is the seat member. Regarding the recessed portion 110, FIGS. 2 and 3, which show the closed and opened states of the discharge valve Vo, can be used as a reference. The sealing point S, that is, the edge of the end portion 44e of the movable valve body 44 is the tapered portion 161t.
The portion seated on the movable valve body 44 is on a tapered portion 161t surrounding the opening of the passage 60. In the embodiment shown in the figure, a bottom wall portion 200 and a cylindrical portion 300 are provided before and after the sealing point S, intersecting the tapered portion 161t. Recess 110
The wall surface of the bottom wall portion 200 at the bottom is perpendicular to the axis of the movable valve body 44, and the distance from the movable valve body 44 side is approximately 0.2 to 0.3 mm when the discharge valve Vo is closed. be. Further, the cylindrical portion 300 on the opening side of the recess 110 is connected to the movable valve body 44 .
The cylindrical portion 30 extends parallel to the axis so as to surround the side periphery of the cylindrical portion 30.
The distance between the inner wall surface of 0 and the side wall of the movable valve body 44 is also 0.2 to 0.
．． It is about 3 mm. The reason why the bottom wall portion 200 and the cylindrical portion 300 are brought close to the movable valve body 44 side is to provide a throttling effect there. Therefore, although it is possible to have a slight range in the degree of proximity, at least 0
．． It should be set to 5 mm or less. By providing such a constriction part, when the brake is released, the discharge valve Vo changes from closed to open, and the liquid from the servo chamber 38 side flows to the discharge valve Vo.
Even when the liquid flows out through the passageway 60 side, there is no squeaking sound as in the conventional case.

[0011] Note that squealing can be prevented if there is only one diaphragm before or after the sealing point S. Therefore, for example, the cylindrical portion 300 side may be omitted, or a plurality of V-shaped notch passages may be provided on the cylindrical portion 300 side.

Furthermore, in the embodiment shown in the figure, the play on the discharge valve Vo side is almost zero, but the movable valve body 44 may also have play that is slightly away from the valve seat side when not in operation. Can be applied.

[0013]

According to the present invention, by changing the shape of the seat member 161 at the tip of the input member 16, the discharge valve V
Since at least one of the front and rear sides of the sealing point S of o has the function of a throttle, the problem of squealing when the brake is released can be effectively solved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of FIG. 1, and is a partial cross-sectional view showing the discharge valve in a closed state.

FIG. 3 is a view showing the same part as FIG. 2, and is a view showing the discharge valve in an open state.

[Explanation of symbols]

10 Hydraulic booster 14 Cylinder body 16 Input member 30 Servo piston 38 Servo room 44 Movable valve body 161 First member (seat member) 161t Taper part 200 Bottom wall part (cross wall part) 300 Cylindrical part (cross wall part) Vi supply valve Vo discharge valve

Claims (2)

[Claims] Claim 1: A servo piston that is located inside a cylinder body and defines a servo chamber at one end; a valve chamber that is formed within the servo piston to enable communication between the servo chamber and a hydraulic pressure release source; A movable valve body that fits together, one end of which protrudes into the valve chamber, and has an opening for a passage communicating with the hydraulic pressure release source on the protruding one end surface, and a recess that opens toward the one end surface of the movable valve body. a seat member that is movable within the valve chamber in response to an operational input; and a tapered portion that gradually increases in diameter toward the movable valve body on a side circumferential wall within the recess, the opening of the movable valve body being A discharge valve structure for a hydraulic booster, comprising: a valve seat that surrounds the movable valve body and on which an edge of the one end surface is seated and unseated, and the valve seat and the edge of the one end surface of the movable valve body constitute a discharge valve. In the hydraulic doubler, in the recess of the seat member, an intersecting wall portion intersecting the tapered portion is provided on at least one of the front and rear sides of the tapered portion on which the edge of one end surface of the movable valve body is seated. Discharge valve structure of power device. 2. The intersecting wall portion is close to the movable valve body, and the passage formed between the cross wall portion and the movable valve body acts as a restriction for liquid flowing from the servo chamber side to the hydraulic pressure release source side. A operative discharge valve structure for a hydraulic booster according to claim 1.