JPH0822668B2 - Hydraulic 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 hydraulic booster used in a vehicle brake to assist the operation of a master cylinder.

[0002]

2. Description of the Related Art Generally, this type of hydraulic booster has a piston inside a cylinder hole of a cylinder body, as disclosed in Japanese Patent Laid-Open No. 2-68258. There are supply and discharge valves in the holes. The valve seats of the two valves are formed as separate members, one of which is a seat member that divides the valve chamber, and the other of which is an input member that receives an operating force. . On the other hand, the number of movable valve bodies that are attached to and detached from the respective valve seats is usually single. The movable valve body includes a tip end portion that is separated from and seated on the discharge valve seat, and a bulge portion that is mounted on and separated from the supply valve seat.

Conventionally, the bulging portion located in the middle of the movable valve body has a spherical shape, and the movable valve body is inserted into the valve hole of the seat member from the valve chamber side, and its tip end is opposed to the input member. The seal area of the supply valve is larger than the seal area of the discharge valve. For this reason, when pressure is introduced into the valve chamber, the movable valve element receives a force in the direction of opening the supply valve, which causes a seal failure of the supply valve, and the biasing force of the spring to prevent the seal failure. There is a problem in that when the value is increased, a rise delay occurs due to the boosting effect.

As a matter of course, in order to make the seal areas of both the supply valve and the discharge valve equal, as shown in Japanese Patent Laid-Open No. 63-287656, the movable valve body has a two-piece structure, and one of the parts has a supply valve. It is also conceivable for the valve part to constitute the valve part of the discharge valve in the other part, respectively. However, this increases the number of parts and reduces the assemblability of the device.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique capable of minimizing the difference between the seal areas of the supply valve and the discharge valve while keeping the movable valve body in a one-piece structure.

[0006]

According to the present invention, the supply valve seat provided in the opening of the seat member is provided by forming a convex curved surface having an arc-shaped cross section, while the bulging portion on the movable valve body side is provided. The outer peripheral surface is a conical surface whose diameter becomes gradually smaller toward the valve hole side along the axis of the movable valve body, or an inclined surface which is a concave curved surface similar to the conical surface, and the apex angle of this inclined surface becomes an acute angle. The shape. Thereby, the seating point of the movable valve body in the supply valve can be set to the inner side in the radial direction, and the seal area of the supply valve can be made close to the seal area of the discharge valve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A hydraulic booster 10 has a cylinder body 14 having a stepped cylinder bore 12 therein. In this booster 10, an operating force from one side of the cylinder body 14 via a pedal or the like is applied to the input member 16, and then a servo action is generated according to the movement of the input member 16, and the assisted force is applied to the cylinder body. It is added to the master cylinder side (not shown) through the output member 18 on the other side of 14.

The input member 16 to which the pedal operating force is applied is composed of a first member 161 penetrating the center of the lid member 20 and a second member 162 movably fitted in the hole at the first end. The lid member 20 is a member that closes the opening of the cylinder hole 12, the outer periphery of which is sealed by an O-ring 22, and the periphery of the first member 161 that penetrates the lid member 20 is sealed by a cup seal 24. On the other hand, the output member 18 located on the opposite side is connected to the end of the piston 30 by the metal fitting 26. Metal fittings 26
The piston 30 and the output member 18, which also function as a spring receiver, are urged toward the lid member 20 by a return spring 28 having a rectangular cross section. Therefore, one end of the piston 30 is in contact with the plate member 21 on the inner circumference of the lid member 20 in a normal state where no operation is performed. The bent plate member 21 is used for the cup seal 2
It also functions as a retainer for 4.

The piston 30 is a hollow structure having a stepped inner hole 32. The inner hole 32 has the largest diameter on the opening side facing the lid member 20, and the diameter is gradually reduced toward the inside. Also, this piston 30
The outer periphery of the seal ring 34, 3 is spaced apart from each other.
6 therewith defining a plurality of chambers in the cylinder bore 12. A portion adjacent to the lid member 20 is a servo chamber 38, a chamber around the piston between the seal rings 34 and 36 is an inlet chamber 40, and a chamber around the output member 18 is a low pressure chamber 42. The low pressure chamber 42 is connected to the reservoir on the master cylinder side, which is a pressure release source, and to the inlet chamber 4
0 respectively communicates with a pressure source including an accumulator and a pump, which are also not shown. The respective seal rings 34, 36 are rubber inner rings 34i, 36i.
And outer rings 34o, 36o made of resin. The outer rings 34o and 36o are provided to reduce the sliding resistance of the piston 30. In order to effectively reduce the sliding resistance, it is important to stably support the outer rings 34o and 36o. Therefore, it is preferable that the inner rings 34i, 36i made of rubber have a rectangular cross section, and the width thereof be set to be about the same as or slightly larger than that of the outer rings 34o, 36o.

Next, look inside the inner hole 32 of the piston 30. At the inner side of the inner hole 32, there is an elongated cylindrical movable valve element 44. The movable valve element 44 is movable in the axial direction of the piston 30 while being supported by the end portion of the piston 30 and the seat member 46. The movable valve body 44 has a flange 45 in the middle thereof, and receives a force from a spring 48 there, and is urged toward the input member 16. Therefore, the bulging portion 50 adjacent to the flange 45 hits the opening portion 52 of the valve hole 47 at the center of the seat member 46. The bulging portion 50 and the opening 52 constitute the supply valve Vi. The supply valve Vi is
This is a valve for supplying the pressure from the external pressure source to the servo chamber 38.

The valve chamber 54 having the spring 48 is provided in the movable valve body 44.
It is partitioned by a seal ring 56 that seals around the end of the output member 18 and a seal ring 57 that seals the outer periphery of the seat member 46. The valve chamber 54 always communicates with the inlet chamber 40 through a passage 55 provided in the piston 30. The seal ring 5 around the movable valve body 44
6 has the same structure as the seal rings 34 and 36 around the piston 30, although the inside and the outside are reversed.

The seat member 46 is integrated with the piston 30 by a tubular member 58 inserted into the inner hole 32 of the piston 30 and a screw ring 59 screwed to the opening of the inner hole 32. The valve hole 47 at the center of the seat member 46 penetrates the seat member 46, and accordingly, the end portion 44 e of the movable valve body 44 near the input member 16 projects from the valve hole 47. The protruding end portion 44e faces the second member 162. The second member 162 is fitted in the hole at the end of the first member 161 with the seal ring 60 interposed therebetween, and is urged by the spring 62 toward the first member 161. A concave portion 162a is formed at the end of the second member 162, and the end portion 44e of the movable valve body 44 is attached to and opposed to the concave portion 162a so as to be separable. The recess 162a is a discharge valve seat and constitutes the discharge valve Vo together with the end portion 44e of the movable valve body 44. The discharge valve Vo is a valve that controls connection and disconnection between the servo chamber 38 side and the low pressure chamber 42 side. The passage 64 provided inside the movable valve body 44 and the passage 66 provided at the end of the output member 18 function as a passage for discharging. Two check valves, that is, the reaction force chamber 6 are provided inside the tubular member 58.
There is a first check valve 71 whose forward direction is from 6 to the relay chamber 68, and a second check valve 72 whose forward direction is the opposite direction. The second check valve 72 functions so as not to introduce the hydraulic pressure into the reaction force chamber 66 until the predetermined pressure is reached,
The first check valve 71 is operated when the pressure difference between the servo chamber 38 and the reaction force chamber 66 reaches the valve opening pressure of the check valve 71 while the hydraulic pressure in the servo chamber 38 is returned to the reservoir side. To return the pressure of the reaction force chamber 66 to.

In the hydraulic booster 10 as described above, in order to make the sealing areas of the discharge valve Vo and the supply valve Vi substantially the same, the valve seat and the valve portion of the supply valve Vi are as follows. Is configured. First, the seat member 46
The supply valve seat 52 at the opening of the valve hole 47 of
The cross-sectional shape is formed by a circular arc or a convex curved surface similar thereto. The bulging portion 50 on the side of the movable valve body 44 that is attached to and separated from the supply valve seat 52 is a conical surface whose outer peripheral surface gradually decreases in diameter toward the valve hole 47 side along the axis of the movable valve body 44. Moreover, the virtual apex angle formed by the conical surface and the axis of the movable valve body 44 is set to an acute angle, preferably about 30 degrees. The conical inclined surface has a shape that is easy to process,
In particular, although it is a preferable shape, an inclined surface having a concave curved surface similar to a conical surface can be used.

With such a shape, the seating point of the bulging portion 50 with respect to the supply valve seat 52 is located inside the movable valve element 44 in the radial direction, and the sealing area of the supply valve Vi is equal to the discharge valve V.
The sealing area of o can be almost the same. As a result, even though the movable valve element 44 has a one-piece structure, the movable valve element 44 is not given unnecessary force due to the influence of the hydraulic pressure. Let me explain a little more about this useless power. After the discharge valve Vo is closed and the supply valve Vi is opened according to the input operation, the chamber 80 around the movable valve element 44 in the valve hole 47, and the tubular member 58 having the spring 62.
The same pressure is introduced into both chambers 82. Then, the discharge valve Vo and the supply valve Vi are both closed in a pressure balanced state. Therefore, the discharge valve Vo and the supply valve V
A force corresponding to each seal area of i acts on the movable valve body 44, but in this case, since the seal areas of both valves are almost the same, almost no force is applied to push the movable valve body 44 toward the output member 18 side. Does not work Therefore, even if the biasing force of the spring 48 in the valve chamber 54 is reduced, the pressure from the pressure source does not leak from the portion of the supply valve Vi and enters the chamber 80 side, and the biasing force of the spring 48 is reduced. There is no rise delay which is a problem when the number increases.

[0015]

According to the present invention, it is possible to bring the difference between the seal areas of the supply valve Vi and the discharge valve Vo close to zero with the movable valve element 44 having a one-piece structure, so that the valve has a poor seal. Can be effectively prevented, and the rising characteristic of boosting action can be improved.

[Brief description of drawings]

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

[Explanation of symbols]

 10 hydraulic booster 14 cylinder body 16 input member 30 piston 38 servo chamber 44 movable valve body 46 seat member 47 valve hole 50 bulge 52 opening (supply valve seat) Vi supply valve Vo discharge valve

Claims (1)

[Claims] 1. A cylinder body having a cylinder hole,
A piston that slidably fits in the cylinder hole and defines a servo chamber on one end side, and is formed in this piston,
An inner hole having an opening on the side of the servo chamber, a seat member for defining a valve chamber in the inner hole, the valve chamber communicating with a pressure source, and the servo member penetrating the seat member, Valve hole that connects the chamber to the valve chamber, a supply valve seat formed in the seat member surrounding the valve chamber side opening of the valve hole, and a bulging portion that can be attached to and detached from the supply valve seat. A movable valve element that extends from the valve chamber side to the servo chamber side through the valve hole, and a spring in the valve chamber that biases the movable valve element toward the supply valve seat. And located on the servo chamber side of the seat member,
An input member capable of pressing the movable valve body toward the valve chamber side in response to an operation, and a discharge valve seat provided on the input member for shutting off the servo chamber from a pressure release source by the seating of the movable valve body. In the hydraulic booster including the above, the supply valve seat is provided by forming a convex curved surface on the peripheral edge of the valve chamber side opening of the valve hole, while the bulging portion has an outer peripheral surface that is movable. an inclined surface which becomes concave curved surface which gradually approximating the conical surface or a conical surface whose diameter increases toward the valve hole side along the axis of the valve body, moreover, a shape in which the top angle of the inclined surface is an acute angle, the Sit on the discharge valve seat of the movable valve body
The outer edge is the same as the part that is guided and supported by the valve hole.
The diameter of the supply valve seat is the smallest.
The inner diameter of the portion guides and supports the movable valve body of the valve hole.
The inner diameter of the portion is the same, and the inclined surface of the bulging portion is
Sit on the smallest opening of the supply valve seat
Hydraulic booster with a tilt angle .