JPH05221310A - Structure of reaction part of pneumatic booster - Google Patents

Abstract

PURPOSE:To stabilize the jump-up characteristic without generating a jump-up greater than a specified value by providing a spring for energizing a reaction transmitting member to the direction for separating from a valve plunger at the time of non-operation with the elastic force corresponding to the specified reaction. CONSTITUTION:A disc-shape reaction transmitting member 100 is provided between an end 32a of an output member 32 and a valve plunger 50. A ring member 200 made of plastic and a spring 300 made of waveform washer are located between the rear surface 100r of the reaction transmitting member 100 and a shoulder part 31 of the movable body 20 side. The spring 300 for specifying the jump-up quantity of a pneumatic booster 10 has the elastic force corresponding to the jump-up quantity. When a valve plunger 50 abuts on the rear surface 100r of the reaction transmitting member 100 with the deformation of the spring 300, the reaction from the output member 32 side is transmitted to the foot of a driver. Since this elastic force of the spring 300 is stabilized, the stabilized jump-up quantity is obtained.

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 giving an assisting force to a brake master cylinder or the like, and more particularly to a reaction force structure of a pneumatic booster having a jump-up function.

[0002]

2. Description of the Related Art Generally, a pneumatic booster of this type includes a movable body in the internal space of a shell, and a boosting function is obtained by a force based on a pressure difference acting on both sides of the movable body. ing. There is a through hole through the center of the movable body,
The end portion of the output member fits from one end side thereof, while the valve plunger interlocking with the input member fits from the other end side thereof.
There is a reaction force transmission member (reaction rubber) made of synthetic rubber between the valve plunger and the output member. The reaction force transmission member transmits the reaction force from the output member side to the input member side through the valve plunger. Regarding the transmission of such reaction force,
It is known that a gap is provided between the valve plunger and the reaction force transmitting member when not in operation to obtain a so-called jump-up action (see, for example, Japanese Utility Model Laid-Open No. 2-3966). According to that technology, the reaction force is not transmitted to the input member for a short time after the operation of the input member is started,
It is possible to reduce the operating force at the initial stage of operation. The time during which the reaction force is not transmitted is until the gap is clogged, and the gap is such that the valve plunger moves to the reaction force transmitting member side as the input member is operated, and the reaction force transmitting member moves to the output member side. It is blocked by receiving a reaction force from it and deforming. When the gap is clogged, the reaction force that has already increased, that is, the reaction force that jumps up is transmitted to the input member side.

However, since the reaction force transmitting member is made of synthetic rubber, the amount of deformation varies due to variations in hardness, the hardness changes due to temperature changes, or the coefficient of friction with respect to the wall surface of the through hole varies. Therefore, there is a problem that the jump-up amount greatly varies and the characteristic becomes unstable. Then, for example, in the winter season, the jump-up amount becomes larger than in other seasons, which causes an unfavorable phenomenon in terms of brake operation feeling.

[0004]

It is an object of the present invention to eliminate a gap between a reaction force transmitting member and a valve plunger so that a jump-up of a predetermined value can always be obtained when a reaction force is transmitted from an output member side. The purpose is to provide.

[0005]

According to the present invention, the non-actuated reaction force transmitting member is urged in the direction away from the valve plunger by the spring having the elastic force corresponding to the required jump-up amount. As the spring, it is preferable to use a metal plate material such as a corrugated washer and locate it between the shoulder portion provided in the through hole of the movable body and the reaction force transmitting member. Therefore, since such a spring defines the jump-up amount, the variation is small and the jump-up characteristic can be stabilized.

[0006]

1 is a view showing the sectional structure of a pneumatic booster to which the present invention is applied. Referring to this FIG.
First, the entire structure of the pneumatic booster will be clarified, and then the points that are the point of the present invention will be described. The pneumatic booster 10 includes an outer peripheral bead portion 12 of a diaphragm 12.
A shell 14 supporting a is provided. Inside the shell 14, there is a sufficient internal space, and the dish-shaped movable body 20 is movably inserted therein. An inner peripheral bead portion 12b of the diaphragm 12 is attached in the middle of the movable body 20, whereby two chambers are defined in the shell 14. One is a transformer room 2 which is divided behind the movable body 20.
2 is the other, and the other is the low-pressure chamber 24 divided in front of the movable body 20. The dish-shaped movable body 20 is made of plastic and integrally includes a tubular portion 26 in the center portion on the rear side thereof. The tubular portion 26 penetrates the shell 14 and projects to the outside. A rubber boot 28 covers the tubular portion 26. The movable body 20 includes a cylindrical portion 26 from the main body portion inside the shell 14.
A through hole 30 that also penetrates is provided. The through hole 30 is a stepped hole, and the end portion 32a of the output member 32 fits from the front side, while the input member 41 fits from the rear side. A front end of the output member 32 is connected to a brake master cylinder (not shown), and a brake pedal is connected to a rear end of the input member 41.

A valve plunger 50 is integrally connected to the front end of the input member 41. The valve plunger 50 constitutes the valve device 60 together with the poppet member 52 around the input member 41 and the like. There are the following three control modes of the valve device 60. One is a state in which the low pressure chamber 24 and the variable pressure chamber 22 are communicated with each other through the passages 54 and 56, while the communication between the variable pressure chamber 22 and the atmosphere is cut off, which eliminates the differential pressure between the variable pressure chamber 22 and the low pressure chamber 24. This is the non-actuated position. The other is a state in which the communication between the variable pressure chamber 22 and the low pressure chamber 24 and the communication between the variable pressure chamber 22 and the atmosphere are both cut off.
This is a neutral position for keeping the differential pressure between the low pressure chamber 24 and the low pressure chamber 24 constant.
Furthermore, one is a state in which the low pressure chamber 24 and the variable pressure chamber 22 are disconnected, and the variable pressure chamber 22 and the atmosphere are in communication with each other.
This is the operating position that produces a differential pressure. The movable body 20 in the shell 14 is located rearward as shown in the figure by the force of the return spring 70 when the movable body 20 is not in operation. When a differential pressure occurs in the cylinder, a force based on the differential pressure assists the operation of the master cylinder.

Now, pay attention to the inside of the through hole 30 of the movable body 20. Looking at the front opening 30a having a relatively large diameter, there is a disc-shaped reaction force transmission member 100 between the end 32a of the output member 32 and the valve plunger 50. The reaction force transmission member 100 is similar to a conventional synthetic rubber member. Usually, this reaction force transmitting member 100 has a front surface 100
f hits the rear surface of the output member 32, while the rear surface 100
The outer peripheral portion of r is supported by the shoulder portion 31 in the middle of the through hole 30. Here, the rear surface 1 of the reaction force transmission member 100
00r and the shoulder 31 on the movable body 20 side, a spring 3 made of a plastic ring member 200 and a corrugated washer.
00 is arranged. The ring member 200 has a spring 300.
One of the spring bearings functions as a guide for the valve plunger 50. On the other hand, the spring 300 defines the jump-up amount of the pneumatic booster 10, and has an elastic force according to the jump-up amount. When the jump-up amount is large, the elastic force of the spring 300 is set large, and when the jump-up amount is small, the elastic force of the spring 300 is set small. Since the spring 300 regulates the jump-up amount, the reaction force transmitting member 100 has a reaction force before the reaction force transmitting member 100 and the valve plunger 50 come into contact with each other before the spring 300 is compressed on the rear surface 100r side. Air gap 150 between the force transmission member 100 and the valve plunger 50
It has enough hardness to not bite and deform.

Therefore, when operating the pneumatic booster 10, the valve plunger 5 is interlocked with the movement of the input member 41.
0 moves so as to fill the void 150, and accordingly,
The spring 300 elastically deforms. Due to the deformation of the spring 300, the valve plunger 50 moves the rear surface 10 of the reaction force transmitting member 100.
In the state of hitting 0r, that is, in the state where the gap 150 is clogged, the reaction force from the output member 32 side is applied to the reaction force transmitting member 10.
0, the valve plunger 50, and the input member 41 to reach the driver's foot on the brake pedal. At this time, the initial reaction force transmitted, that is, the jump-up amount is determined by the elastic force of the spring 300 and the distribution degree by the ring member 200 and the valve plunger 50. The elastic force of the spring 300 is more stable than that of the reaction force transmission member 100 made of rubber even if there is a change in temperature or the like, and thus a stable jump-up amount can be obtained.

The ring member 200 may be omitted by embedding a part of the spring 300 made of a metal plate in the rear surface 100r of the reaction force transmitting member 100.

[0011]

According to the present invention, in addition to the reaction force transmission member 100 made of synthetic rubber, the spring 300 for urging the reaction force transmission member 100 away from the valve plunger 50 side is provided. The jump-up characteristic can be stabilized without causing a jump-up exceeding the specified value.

[Brief description of drawings]

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

[Explanation of symbols]

 10 pneumatic booster 30 through hole 32 output member 41 input member 50 valve plunger 100 reaction force transmitting member 150 void 200 ring member 300 corrugated washer (spring)

Claims (2)

[Claims] 1. An end of an output member fits into a through hole of a movable body provided movably in an internal space of a shell from one end side thereof, and a valve plunger interlocking with an input member fits from the other end side thereof. , A reaction force transmission member made of synthetic rubber is provided between the valve plunger and the end portion of the output member, and one end portion of the reaction force transmission member engages with the end portion of the output member. In addition, in the reaction force part structure of the pneumatic booster, the other end partly engages with the movable body, and further engages with the valve plunger when a predetermined reaction force acts on the output member. A reaction force part structure of a pneumatic booster provided with a spring for urging the reaction force transmission member in a direction away from the valve plunger when not in operation with an elastic force corresponding to the predetermined reaction force. 2. The reaction force portion of the pneumatic booster according to claim 1, wherein the spring is made of a metal plate material and is located between a shoulder portion provided in the through hole and the reaction force transmission member. Construction.