JPH0867239A - Negative pressure type booster - Google Patents

Abstract

PURPOSE: To markedly recuce an operating input when starting action, by forming a diameter in a point end of a seat of a negative pressure controlling seal valve almost equal to or less than a diameter formed by a diaphragm between a control valve and an internal peripheral side of a cylindrical part. CONSTITUTION: A cylinder part 19a and a bead part 19b, playing a role of diaphragm, are provided in a control valve in a cylindrical part, to provide an atmospheric seal part 19c and a negative pressure seal part 19d in a front side end. When a rod 17 is operated, the negative pressure seal part 19d comes into contact with a negative pressure controlling seal valve 15a of almost the same small diameter, to interrupt a change pressure chamber 13 from a fixed negative pressure chamber 12, and a plunger atmospheric controlling seal valve 16a is lifted from the atmospheric seal part 19c of the control valve, to increase a pressure of the change pressure chamber 13. This propulsive force is transmitted to an output member 25 through a rubber disk 26. Since operating resistance in this stage is almost not changed, an operating input at starting of action is markedly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative pressure type booster and is used in a vehicle brake device to reduce an operation input at the start of operation.

[0002]

2. Description of the Related Art Conventionally, as a negative pressure type booster of this type,
Those described in Japanese Utility Model Laid-Open No. 2-99061 can be mentioned. The negative pressure type booster disclosed in the above publication has a housing, a movable wall partitioning the inside of the housing into a constant negative pressure chamber and a variable pressure chamber, and a cylinder extending from the center of the movable wall to the outside of the housing. A cylindrical portion, a plunger concentrically and slidably fitted in the cylindrical portion, and a plunger connected in the cylindrical portion to the plunger by a ball joint, and from the tip end opening of the cylindrical portion, An input member composed of a rod extending out of the cylindrical portion; and an atmosphere control seal valve formed at one end of the plunger facing the opening of both ends of the plunger, A negative pressure control seal valve formed on the inner surface of the cylindrical portion so as to be located on the outer peripheral side of the atmosphere control seal valve and oriented in the same direction as the atmosphere control seal valve, and the atmosphere control seal valve and Negative pressure control The control valve is provided with a seal portion facing the seal valve at one end of a control valve having a tubular portion and a flange portion that can expand and contract in the axial direction according to the axial movement of the rod, and the other end of the control valve has the cylindrical shape. A control valve that is airtightly fixed to the inner surface of the part,
A first compression coil spring that urges the seal portion of the control valve toward the negative pressure control seal valve; and, in a normal state, the atmosphere control seal valve contacts the seal portion and the seal portion A second compression coil spring that urges the rod in the cylindrical portion to lift it from the pressure control seal valve, and a stopper that defines the amount of displacement of the plunger with respect to the cylindrical portion by the force of the second compression coil spring. And a reaction force mechanism that applies a reaction force corresponding to the propulsive force generated in the movable wall to the plunger due to the pressure difference between the constant negative pressure chamber and the variable pressure chamber, wherein the variable pressure chamber is for controlling the atmosphere. To the atmosphere through the gap between the seal valve and the seal portion, and to the constant negative pressure chamber through the gap between the negative pressure control seal valve and the seal portion, respectively. In addition to the general configuration in communication with,
In the normal state, the seal portion of the control valve receives the pressure difference between negative pressure and atmospheric pressure and controls the area of the pressure receiving surface that urges the input member to oppose the force of the second compression coil spring. The control valve has an urging force that is reduced by blocking the radially extending portion on the other end side of the valve from the atmosphere and urges the input member at the start of operation by the differential pressure between the negative pressure and the atmospheric pressure. From the stage until the seal portion comes into contact with the negative pressure control seal valve, the seal portion of the control valve comes into contact with the negative pressure control seal valve and the atmosphere control seal valve comes into contact with the control valve of the control valve. By shifting to the stage of lifting from the seal portion, the operating resistance is reduced and the increase in operating resistance is reduced, and the applied load of the second compression coil spring and the first compression coil are reduced. The operation resistance force based on the applied load of the spring (the applied load of the second compression coil spring when the first compression coil spring is stretched between the seal portion and the cylindrical portion). The operation input at the start of operation is reduced.

[0003]

However, in the negative pressure type booster disclosed in the above publication, the diameter formed by the tubular portion of the control valve, that is, the size of the pressure receiving surface is reduced, so that the negative pressure type Although it is possible to reduce the rising load at the time of operating input of the booster, the size of the pressure receiving surface is smaller than the diameter formed by the valve seat of the negative pressure control seal valve, so the control valve At the time of operation, the seal part receives the differential pressure between the atmospheric pressure and the negative pressure that has flowed in from the gap between the atmospheric control seal valve and the seal part of the control valve, so that the seal part receives the negative pressure control seal valve. There is a possibility that the seal portion is urged to be released and the seal portion may be separated from the negative pressure control seal valve, and the responsiveness of the negative pressure type booster may be deteriorated.

Therefore, an object of the present invention is to provide a negative pressure type booster capable of reducing the operation input at the start of operation and solving the above problems.

[0005]

In order to solve the above-mentioned problems, the invention of claim 1 is directed to a housing, a movable wall partitioning the inside of the housing into a constant negative pressure chamber and a variable pressure chamber, and a center of the movable wall. Portion extending from the housing to the outside of the housing, an input member having a flange portion on the inner peripheral side of the cylindrical portion, an atmosphere control seal valve formed at one end of the input member, and an atmosphere control seal valve And a negative pressure control seal valve formed on the inner circumference of the cylindrical portion so as to face the same direction as the atmospheric control seal valve, and an atmospheric control seal valve and a negative pressure control seal valve. A control valve having an atmospheric seal portion and a negative pressure seal portion that come into contact with the diaphragm, a diaphragm formed between the control valve and the inner peripheral side of the cylindrical portion, and a negative pressure seal portion on the negative pressure control seal valve side. Coil spring urged toward And a reaction force mechanism for applying a reaction force corresponding to the propulsive force generated in the movable wall due to the pressure difference between the constant negative pressure chamber and the variable pressure chamber to the input member, and the variable pressure chamber is an atmosphere control seal valve. To the atmosphere through the gap between the atmosphere seal part,
Further, in the negative pressure type booster that communicates with the constant negative pressure chamber through the gap between the negative pressure control seal valve and the negative pressure seal portion, the diameter of the tip of the valve seat of the negative pressure control seal valve is The diameter is set to be substantially the same as or smaller than the diameter formed by the diaphragm.

In the negative pressure type booster of claim 2, in addition to the invention of claim 1, the control valve and the diaphragm are integrally formed by an elastic member.

[0007]

In the negative pressure type booster of the first aspect, the operation is started by applying an operation input to the input member. The input member is moved by the urging force generated by the operation input applied to the input member and the pressure difference between the negative pressure and the atmospheric pressure, that is, the urging force acting on the input member and the load of the coil spring. The pressure seal portion comes into contact with the negative pressure control seal valve of the cylindrical portion to disconnect the communication between the variable pressure chamber and the constant negative pressure chamber. Here, the diaphragm always airtightly separates the variable pressure chamber and the constant negative pressure chamber in the cylindrical portion.

After that, the input member is continuously moved to lift the atmospheric control seal valve from the atmospheric seal portion, so that the variable pressure chamber communicates with the atmospheric pressure, the atmospheric pressure flows into the variable pressure chamber, and the pressure in the variable pressure chamber rises. As a result, a propulsive force is generated in the movable wall to move the movable wall. At this stage, since the negative pressure seal portion is in contact with the negative pressure control seal valve, the urging force for urging the control valve due to the differential pressure between the negative pressure and the atmospheric pressure does not act on the input member. The member is moved by the sum of the urging force applied to the movable wall by the applied operation input and the differential pressure between the negative pressure and the atmospheric pressure, and the operation input applied to the input member.

As described above, the operating resistance when the negative pressure seal portion of the control valve is in contact with the negative pressure control seal valve and the atmospheric control seal valve is lifted from the atmospheric seal portion is the operating resistance of the atmospheric control seal valve. It increases compared to the operating resistance at the stage of contact with the atmosphere seal part and the negative pressure seal part being lifted from the negative pressure control seal valve, but the increase is only the load of the coil spring, and the negative pressure and large The biasing force acting on the input member due to the pressure difference from the atmospheric pressure is the negative pressure when the atmospheric control seal valve is in contact with the cylindrical atmospheric seal part and the negative pressure seal part is lifted from the negative pressure control seal valve. Since the seal part is in contact with the negative pressure control seal valve and the atmospheric control seal valve is lifted from the atmospheric seal part, the operation input at the start of operation is compared to the conventional negative pressure booster. Significantly reduced Rukoto can.

[0010]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the negative pressure type booster of the present invention. Housing 1 of negative pressure type booster 10
1 is the rear portion 11 in the rear side opening of the front portion 11a.
They are joined by inserting b. Housing 11
The movable wall 14 that divides the interior into a front side constant negative pressure chamber 12 (which communicates with a negative pressure source such as an engine intake pipe or a negative pressure pump not shown) and a rear side variable pressure chamber 13 is a pressure receiving plate 14a.
And a bending portion 14b. The pressure receiving plate 14 a is joined to the outer periphery of the front end of the cylindrical portion 15 at its inner peripheral portion and is integrated with the cylindrical portion 15. The flexible portion 14b has its outer peripheral bead portion airtightly sandwiched between the front portion 11a and the rear portion 11b of the housing 11, and its inner peripheral bead portion is airtightly fitted into the annular groove on the outer periphery of the cylindrical portion 15. ing.

The cylindrical portion 15 extends from the central portion of the movable wall 14 to the rear side, and the rear side portion 11b of the housing 11 is provided.
Through the airtight and slidably, and projects out of the housing 11. The input member is the plunger 16 and the rod 1.
7, the input member is formed, the plunger 16 slidably penetrates into the cylindrical portion 15, and is fitted to the front end of the rod 17 by a ball joint. Air control seal valve 16 for controlling the inflow of air
It has a at the rear end. The control valve 19 in the cylindrical portion 15 integrally forms a cylindrical portion 19a and a bead portion 19b having a function as a diaphragm, and a bead portion 19b at the rear end of the cylindrical portion 19a is formed by the retainer 20 into a cylindrical portion. Is airtightly fixed to the inner surface of the cylinder 19a.
Has an atmosphere seal portion 19c and a negative pressure seal portion 19d at its front end. The atmosphere seal portion 19c faces the atmosphere control seal valve 16a of the plunger 16. The negative pressure seal portion 19d faces the negative pressure control seal valve 15a. The negative pressure control seal valve 15 a is for controlling the negative pressure transmission from the constant negative pressure chamber 12 to the variable pressure chamber 13.

Atmospheric sealing portion 1 of control valve 19
9c and the negative pressure seal portion 19d are urged toward the atmosphere control seal valve 16a and the negative pressure control seal valve 15a by the first compression coil spring 21 interposed in a compressed state between the 9c and the negative pressure seal portion 19d. Has been done.

The rod 17 has a second compression coil spring 22 inserted in a compressed state between the rod 17 and the retainer 20.
Is biased toward the rear side by. The force (load) of the second compression coil spring 22 brings the atmosphere control seal valve 16a of the plunger 16 into contact with the atmosphere seal portion 19c of the control valve 19, and causes the negative pressure seal portion 19d of the control valve 19 to move to the plunger 16 Can be lifted from the negative pressure control seal valve 15a against the pressure difference between the negative pressure and the atmospheric pressure that act to bias the front side. In order to define the amount of displacement of the plunger 16 to the rear side with respect to the cylindrical portion 15 by the second compression coil spring 22, the key member 23 having a notch into which the reduced diameter portion 16b of the plunger 16 fits is formed on the cylindrical portion 15. It is installed throughout.

The thickness of the key member 23 is set to be smaller than the thickness of the key member insertion hole of the cylindrical portion 15 by a predetermined amount. Therefore, the key member 23 is located in the axial direction of the plunger 16 with respect to the cylindrical portion 15. It can be displaced by a fixed amount. When the key member 23 is displaced to the rearmost side with respect to the cylindrical portion 15, the negative pressure seal portion 19d of the control valve 19 is provided.
Is lifted from the negative pressure control seal valve 15a by the maximum amount, and the atmosphere in the variable pressure chamber 13 is rapidly discharged to the constant negative pressure chamber 12. Both ends of the key member 23 project from the cylindrical portion 15, can contact the inner surface of the housing 11, and function as stoppers that determine the return position of the movable wall 14. That is, the movement of the movable wall 14 toward the rear side by the force of the return spring 24 is terminated by bringing the cylindrical portion 15 into contact with the inner surface of the housing 11 via the key member 23. The lift amount of the negative pressure seal portion 19d of the control valve 19 from the negative pressure control seal valve 15a in the state where the movable wall 14 is restored is very small.

A cup-shaped portion 25a at the rear-side end of the output member 25 is slidably fitted into the front-side end of the cylindrical portion 15, and the rubber disc 2 is inserted in the cup-shaped portion 25a.
6 are accommodated. As is well known, such a configuration constitutes a reaction force mechanism that applies a reaction force proportional to the propulsive force of the movable wall 14 to the plunger 16.

Next, the operation will be described. The states shown in FIGS. 2 and 3 are views showing the main part of this embodiment in a non-operating state in which no operation input is applied to the rod 17 and an operating state in which an operation input is applied to the rod 17. In the non-operating state of FIG. 2, the atmosphere control seal valve 16a of the plunger 16 is replaced with the atmosphere seal portion 19c of the control valve 19.
The negative pressure seal portion 19d is lifted by a small amount from the negative pressure control seal valve 15a to transfer the negative pressure of the constant negative pressure chamber 12 to the variable pressure chamber 13. Therefore, the variable pressure chamber 13 has the same negative pressure as the constant negative pressure chamber 12, and no propulsive force is generated in the movable wall 14.

When an operation input is applied to the rod 17, the operation input transmitted to the rod 17 is the negative pressure seal portion 1 of the control valve 19 due to the differential pressure between the atmospheric pressure and the negative pressure.
9d and the force that biases the plunger 16 toward the front side and the force of the second compression coil spring 22 are exceeded (in other words, control is performed by the operation input transmitted to the rod 17 and the differential pressure between atmospheric pressure and negative pressure). If the sum of the negative pressure seal portion 19d of the valve 19 and the biasing force that biases the plunger 16 to the front side overcomes the load of the second compression coil spring 22, the rod 17 and the plunger 16 move to the front side and control The negative pressure seal portion 19d of the valve 19 follows. As a result, the negative pressure seal portion 19d of the control valve 19 contacts the negative pressure control seal valve 15a as shown in FIG.
And the operating input transmitted to the rod 17 is increased by the sum of the force of the first compression coil spring 21 and the urging force due to the differential pressure between the atmospheric pressure and the negative pressure acting on the control valve 19. The atmosphere control seal valve 16a of 16 lifts from the air seal portion 19c of the control valve 19 and passes through the cylindrical portion 15 to transform the chamber 1.
3, the pressure in the variable pressure chamber 13 rises. Transformer room 13
Is higher than the pressure in the constant negative pressure chamber 12, and the movable wall 1
4, a propulsive force is generated, and this propulsive force is transmitted to the output member 25 via the rubber disk 26, and the movable wall 14 and the output member 15 move to the front side.

When the propulsive force of the movable wall 14 reaches a predetermined value due to the pressure increase in the variable pressure chamber 13, the portion of the rubber disk 26 facing the plunger 16 bulges toward the plunger 16 side and comes into contact with the plunger 16 to contact the movable wall. A reaction force to the rear side proportional to the propulsive force of 14 is applied to the plunger 16.

In this embodiment, the atmospheric control seal valve 16a is used.
Although the atmospheric seal portion 19c is arranged on the front side of the negative pressure control seal valve 15a and the negative pressure seal portion 19d, it may be arranged on the rear side of the rear negative pressure seal portion 19d.

As described above, according to the present invention, the negative pressure seal portion 19d of the control valve 19 contacts the negative pressure control seal valve 15a and the atmospheric control seal valve 16a is lifted from the atmospheric seal portion 19c. The operating resistance increases as compared with the operating resistance when the atmosphere control seal valve 16a is in contact with the atmosphere seal portion 19c and the negative pressure seal portion 19d is lifted from the negative pressure control seal valve 15a. Minute is substantially the first compression coil spring 2
It is considered that there is only one load, and the biasing force acting on the input member due to the differential pressure between the negative pressure and the atmospheric pressure is the atmospheric control seal valve 1.
6a is in contact with the atmospheric seal portion 19c of the cylindrical portion 15 and the negative pressure seal portion 19d is lifted from the negative pressure control seal valve 15a, and the negative pressure seal portion 19d is in contact with the negative pressure control seal valve 15a. And atmosphere control seal valve 16a
Is almost the same as when the air is lifted from the atmosphere seal portion 19c, the operation input at the time of starting the operation can be significantly reduced as compared with the conventional negative pressure type booster.

[0022]

According to the invention of claim 1, the diameter of the valve seat of the negative pressure control seal valve is made small so as to be substantially the same as the cylindrical portion of the control valve. Even if the operation input is applied, the seal portion of the control valve receives almost no differential pressure, and the rising load of the control valve can be reduced without increasing the force of the compression coil spring.

According to the invention of claim 2, in addition to the effect of claim 1, the valve seat of the atmosphere control seal valve is arranged on the front side of the negative pressure booster from the small diameter portion of the negative pressure control seal valve. By doing so, the atmospheric control seal valve can have the same diameter as the conventional one. As a result, it is possible to reduce the operation input at the start of operation without impairing the responsiveness of the device.

[0024]

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a negative pressure type booster of the present invention.

FIG. 2 is a main enlarged view of the negative pressure type booster of the present invention when there is no operation input.

FIG. 3 is a main enlarged view when an operation input is applied to the negative pressure type booster of the present invention.

[Explanation of symbols]

 10 ... Negative pressure type booster 11 ... Housing 12 ... Constant negative pressure chamber 13 ... Transformer chamber 14 ... Movable wall 15 ... Cylindrical part 15a ... Negative of cylindrical part Pressure control seal valve 16 ... Plunger 16a ... Plunger atmosphere control seal valve 19 ... Control valve 19a ... Control valve cylinder 19b ... Control valve bead 19c ... Control Atmospheric seal part of valve 19d ... Negative pressure seal part of control valve 20 ... Retainer 21 ... First compression coil spring 22 ... Second compression coil spring 25 ... Output member 26 ... Rubber disk

Claims (2)

[Claims] 1. A housing, a movable wall that divides the inside of the housing into a constant negative pressure chamber and a variable pressure chamber, a cylindrical portion that extends from a central portion of the movable wall to the outside of the housing, and a cylindrical portion of the cylindrical portion. An input member having a flange portion on the inner peripheral side; an atmospheric control seal valve formed on the outer peripheral portion of the input member; and an atmospheric control seal valve located on the outer peripheral side of the atmospheric control seal valve. A negative pressure control seal valve formed on the inner circumference of the cylindrical portion so as to face the same direction, and an atmospheric seal portion and a negative valve that can contact the atmospheric control seal valve and the negative pressure control seal valve, respectively. A control valve having a pressure seal portion, a diaphragm provided between the control valve and the inner peripheral side of the cylindrical portion, and urging the negative pressure seal portion toward the negative pressure control seal valve side. Coil spring and front A reaction force mechanism for applying a reaction force corresponding to a propulsive force generated in the movable wall to the input member due to a pressure difference between the constant negative pressure chamber and the variable pressure chamber, and the variable pressure chamber for controlling the atmosphere. The negative pressure control seal valve and the negative pressure seal are connected to the atmosphere through a gap between the seal valve and the atmosphere seal portion, and when the atmosphere control seal valve and the atmosphere seal portion are closed. In a negative pressure type booster that communicates with the constant negative pressure chamber via a gap between the negative pressure control seal valve and the negative pressure control seal valve, the diameter of the tip of the valve seat of the negative pressure control seal valve is substantially the same as the diameter formed by the diaphragm. Negative pressure type booster having a diameter or less. 2. The negative pressure type booster according to claim 1, wherein the control valve and the diaphragm are integrally formed by an elastic member.