JPH07149228A - Differential pressure type booster - Google Patents

Abstract

PURPOSE:To constitute a booster capable of changing a boosting ratio at the time when operating force of an input rod is weak and at the time when it is strong and varying the boosting ratio and a varying point of the boosting ratio at low cost. CONSTITUTION:A housing 10, a power piston 151 partitioned into constant pressure chambers Ra2, Rb2 and variable pressure chambers Ra1, Rb1, a control valve selectively communicating the variable pressure chambers to a high pressure source or the constant pressure chambers and an input rod 41 connected to an air valve are provided. Additionally, a ring groove 431a provided at least in the neighbourhood of an outer periphery of a contact surface with a reaction disc 432 of the output rod in the axial direction is furnished in a differential pressure type booster furnished with the reaction disc 432 transmitting driving force generated on the power piston 151 by pressure differential between the constant pressure chambers and the variable pressure chambers from the power piston to the output rod and adding reaction force to the air valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure type booster for boosting and outputting an operating force exerted on an input rod by utilizing a differential pressure between a constant pressure chamber and a variable pressure chamber.

[0002]

2. Description of the Related Art Conventionally, in a differential pressure type booster, a reaction disk made of rubber or the like is provided at the tip of an input rod to which the pedaling force from a brake pedal is input, and the pedaling force is transmitted to a master cylinder following the reaction disk. An output rod is provided. Further, the power piston disposed in the housing so as to be slidable in the axial direction and the movable wall that moves integrally with the power piston divide the internal space formed by the housing into a constant pressure chamber and a variable pressure chamber. The operation of such a differential pressure type booster is such that the variable pressure chamber is partitioned from the constant pressure chamber by the operation of the control valve by the forward movement of the input rod and communicated with the high pressure source, and the forward movement of the power piston due to the differential pressure between the constant pressure chamber and the variable pressure chamber. Then, the output rod is pressed through the reaction disc, and the pedal force is transmitted to the output rod by determining the boost ratio by the reaction disc by directly pressing the reaction disc of the input rod.

For example, in the technique disclosed in Japanese Examined Patent Publication No. 3-24383, the reaction disk for determining the boosting ratio is arranged on the inner disk on the disk and on the outer side of the inner disk with a gap, and output. And an outer disc having a receding contact surface that is annular with respect to the shaft. In the reaction disc having this structure, the contact area with the output rod is small when the operating force of the input rod is light, and the contact area with the output rod is large when the operating force is strong. Therefore, when the operating force is light, the boosting ratio is low due to the contact of only the inner disc, and even if the brake pedal is lightly depressed, the brake does not work too much, and the fine adjustment operation of the braking force is facilitated and the brake feeling is improved. On the other hand, when the operating force is strong, the entire reaction disc comes into contact with the output rod due to the compression deformation of the inner disc, and a specified boosting ratio can be obtained, which improves the braking effect.

[0004]

The reaction disc is formed by pouring a melted rubber into a mold, and when the boost ratio or the change point of the boost ratio is changed, the reaction disc is removed from the reaction disc. Dimensions such as diameter and thickness are changed, and a new mold is required to mold it. Since the above-mentioned conventional reaction disc is composed of the inner disc and the outer disc, a mold satisfying this shape and the dimensions of each part is required, resulting in a significant cost increase. Further, in order to change the boost ratio and the change point of the boost ratio, it is necessary to change the size of each part of the reaction disk and to manufacture a new mold, which is expensive.

According to the present invention, the boost ratio can be changed when the operating force of the input rod is weak and when it is strong, and the boost ratio and the change points of the boost ratio can be changed at low cost. Is a technical issue.

[0006]

In order to solve the above technical problems, the technical measures taken in the invention of claim 1 are provided at least in the vicinity of the outer circumference of the axial contact surface of the output rod with the reaction disk. That is, it has an annular groove.

The technical means taken in the second aspect of the present invention is to provide an annular groove provided at least near the outer periphery of the axial contact surface of the piston with the reaction disk.

[0008]

The operation of the invention of claim 1 will be described. The boost ratio is
When a light operating force is applied to the input rod, the reaction disc comes into contact with a surface other than the annular groove of the axial contact surface of the output rod, so a low boost ratio is obtained, and when a strong operating force is applied, the reaction disc Has a high boost ratio because it contacts the entire axial contact surface of the output rod. On the other hand, by arbitrarily setting the width and depth of the annular groove, the boost ratio and the change point of the boost ratio can be freely changed. Since it is provided at least in the vicinity of the outer periphery of the axial contact surface, the boost ratio and change points of the boost ratio can be easily and inexpensively cut by cutting the axial contact surface of the output rod with the reaction disk. Will be able to change.

The operation of the invention of claim 2 will be described. The boost ratio is such that when a light operating force is applied to the input rod, the reaction disc comes into contact with the surface of the annular groove body on the axial contact surface of the input rod, so a low boost ratio is obtained and a strong operating force is applied. When the reaction disk is opened, the reaction disk comes into contact with the entire axial contact surface of the input rod, so that a high boost ratio is obtained. On the other hand, similarly to the invention of claim 1, the width and the depth of the annular groove can be arbitrarily set to freely change the boost ratio and the change point of the boost ratio. By providing at least in the vicinity of the outer periphery of the axial contact surface of the rod with the reaction disk, it is possible to easily and at low cost by cutting the axial contact surface of the input rod with the reaction disk, and at a low cost. It becomes possible to change the change point of the ratio.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a first embodiment in which the present invention is applied to a negative pressure type booster, and FIG. 2 is an enlarged sectional view around a reaction disk. In the figure, the housing 10 is
It comprises a first shell 13, a second shell 12, and a third shell 11. The housing 10 is formed by hermetically fitting the second shell 12 and the first shell 13 inside the third shell 11.

A closed space Rb is formed between the first shell 13 and the second shell 12.

A movable wall 15 is fixed in the space Rb. The interior of the space Rb is further divided by a movable wall 15 into a constant pressure chamber Rb1 and a variable pressure chamber Rb2. Movable wall 15
Is a metal power piston 151 and an annular plate 1
52 and a diaphragm 153. The inner peripheral portion of the annular plate 152 is engaged with the outer peripheral portion of the power piston 151. Further, the inner peripheral portion 153a of the diaphragm is supported on the outer periphery of the power piston 151, and is sandwiched between the inner peripheral portions of the sandwiching member 154 and the annular plate pressure 152, and the outer peripheral portion 153b is located in the first shell 13 and the third shell. It is tightly sandwiched between 11 and 11.

A communication passage 1 is provided inside the power piston 151.
51a and 151b are formed. The communication passage 151a connects the constant pressure chamber Ra2 and the constant pressure chamber Rb2. Communication passage 1
51b connects the transformer room Ra1 and the transformer room Rb1.

A plurality of bolts 21 are fixed to the first shell 13 and are attached to a dashboard (not shown) by the bolts 21.

A recess 111 for fixing a master cylinder (not shown) is formed in the third shell 11.
In the recess 111, the third shell 11 and the output rod 4
A seal 35 for hermetically sealing the gap with 3 is loosely inserted. The seal 35 is fixed by inserting the master cylinder, and further has a groove portion 35a for air escape.
Is provided.

Inside the first shell 13, the second shell 12 is provided.
The third shell 11 and the second shell 12 are fixed by caulking.
A sealed space Ra is formed between and. The movable wall 14 is fixed in the space Ra. Inside the space Ra,
By the movable wall 14, a constant pressure chamber Ra1 and a variable pressure chamber Ra2 are further provided.
Is divided into The movable wall 14 is an annular plate 142.
And a diaphragm 143. Annular plate 142
One end of is supported by the step portion 151c of the power piston 151. The outer peripheral end 143a of the diaphragm 143 is
The second shell 12 and the third shell 11 are hermetically sandwiched, and the inner peripheral end 143b is sandwiched by the cut portion of the power piston 151 and the sandwiching portions 151c and 151d, and the inner peripheral portion of the annular plate 142. There is.

A reinforcing plate 16 is fixed to the inside of the third shell 11. A plurality of bolts 22 for fixing the master cylinder are fixed to the reinforcing plate 16.

The third shell 11 has a connector 1 for communicating the space Ra2 with a negative pressure source (not shown) such as an internal combustion engine.
7 is connected.

Further, the second shell 12 and the power piston 15
An annular seal member 31 fixed to the second shell 12 is provided between the two. An annular seal member 32 fixed to the first shell 13 is provided between the first shell 13 and the power piston 151. And
The power piston 151 is supported by the seal members 31 and 32 and can slide in the axial direction of the housing 10.

Inside the power piston 151, an air cleaner 51, an input rod 41, an air valve 42 and an output rod 43 are inserted. An air valve 42 is slidably inserted into the power piston 151 while its movement is restricted by a key 151e. A ball joint portion 411 is formed at one end of the input rod 41. The ball joint portion 411 is the first air valve 42.
It is inserted into the inside of 1 and fixed by caulking.
The input rod 41 is slidably supported by the first air valve 421. The air valve 42 is the input rod 4
1 and a second air valve 422, one end of which contacts the first air valve 421.

A control valve is formed between the input rod 41 and the air valve 42. The control valve includes a control valve 61 biased toward the air valve 42 by a spring 60, a power piston 151, and a first valve.
And an air valve 421. The control valve 61 has an end portion with the power piston 151 and the holding member 5
It is held by 2 and. The holding member 52 is in contact with one end of a spring 53 that biases the spring 60 and the input rod 41 toward the initial position. The other end of the spring 53 is in contact with the flange portion 412 of the input rod, and further holds the air cleaner 51 by the extra winding portion wound a plurality of times on the outer peripheral side.

A cup portion 431 is formed at one end of the metal output rod 43, and a reaction disc 432 is inserted inside the cup portion 431. An annular groove 431a is provided on the outer circumference of the bottom surface of the cup portion 431 (the surface that comes into contact with the reaction disc 432 in the axial direction).
Further, the output rod 43 is slidably supported by the seal member 35 of the recess 111 of the third shell 11.

A main spring 45 is provided between the cup portion 431 and the third shell 11, and the main spring 45 presses the power piston 151 toward the non-operating position.

Next, the operation of this embodiment will be described.

When a forward (leftward in FIG. 1) operating force is applied to the input rod 41 by depressing a brake pedal (not shown), it is movable due to a pressure increase in the variable pressure chambers Ra1 and Rb1 caused by a well-known operation of the control valve. Walls 14 and 15
Is pushed forward and the power piston 151 is pushed. The forward movement of the power piston 151 is transmitted to the output rod 43 via the reaction disc 432. On the other hand, the reaction disc 432 is elastically deformed by the pressing force of the power piston 151 and presses the second air valve 422 to generate a reaction force on the input rod 41.

FIG. 3 is a diagram showing the relationship between the operating force (input) to the brake pedal and the output from the output rod 43. In the same figure, points a and b show known jumping characteristics, and show until the reaction disk 432 elastically deforms and comes into contact with the second air valve 422.
Points b to c show the reaction disc 432 further elastically deformed and filled in the annular groove 431a. Points c to d show the time from when the reaction disc 432 is filled in the annular groove 431a to when the assisting force of the booster disappears. After the input exceeds the point d, the operating force applied to the input rod 41 is directly output to the output rod 43.

As can be seen from FIG. 3, in the region of points c to d, the boosting ratio is larger than in the region of points b to c, and the braking effectiveness is increased. Accordingly, when a light operating force is applied to the input rod 41, the reaction disc 432 comes into contact with a surface other than the annular groove 431a of the axial contact surface of the output rod 43, so that a low boosting ratio is obtained and a strong operating force is obtained. When is added,
Since the reaction disk 432 contacts the entire axial contact surface of the output rod 43, a high boost ratio can be obtained.

FIG. 4 is a sectional view of a negative pressure type booster according to a second embodiment of the present invention. In the figure, only differences from the first embodiment will be described. In the negative pressure type booster of the second embodiment, the reaction disc 432 is held by the metal reaction case 151f fitted in the fitting hole 151e of the power piston 151.

The annular groove 151g is provided on the outer periphery of the contact surface of the reaction case 151f with the reaction disc 432, and is similar to the negative pressure type booster of the first embodiment. When the input to 41 is small, a low boost ratio is obtained, and when the input to the input rod 41 is high, a high boost ratio is obtained.

The boosting ratio can be freely changed by changing the widths of the annular grooves 431a and 151g in both the negative pressure type boosters of the first and second embodiments. Also, by changing the depth of the annular grooves 431a and 151g,
The input value at the change point of the boost ratio (point c in FIG. 3) can be changed.

As described above, in the first and second embodiments,
By arbitrarily setting the width and depth of the annular grooves 431a and 151g, the boost ratio and the change point of the boost ratio can be freely changed. In the first embodiment, the cup of the output rod is changed. The bottom surface of the portion 431 (the axial contact surface with the reaction disc 432) and the axial contact surface with the reaction disc 432 of the reaction case 151f in the second embodiment can be easily and inexpensively doubled by cutting. The change points of the power ratio and the boost ratio can be changed.

[0033]

The effect of the invention of claim 1 will be described. The boost ratio is such that when a light operating force is applied to the input rod, the reaction disc comes into contact with a surface other than the annular groove of the axial contact surface of the output rod, so a low boost ratio is obtained and a strong operating force is applied. When the reaction disk is pushed, the reaction disk comes into contact with the entire axial contact surface of the output rod, so that a high boost ratio is obtained. On the other hand, by arbitrarily setting the width and depth of the annular groove, the boost ratio and the change point of the boost ratio can be freely changed. Since it is provided at least in the vicinity of the outer periphery of the axial contact surface, the boost ratio and change points of the boost ratio can be easily and inexpensively cut by cutting the axial contact surface of the output rod with the reaction disk. Will be able to change.

The effect of the invention of claim 2 will be described. The boost ratio is such that when a light operating force is applied to the input rod, the reaction disc comes into contact with the surface of the annular groove body on the axial contact surface of the input rod, so a low boost ratio is obtained and a strong operating force is applied. When the reaction disk is opened, the reaction disk comes into contact with the entire axial contact surface of the input rod, so that a high boost ratio is obtained. On the other hand, similarly to the invention of claim 1, the width and the depth of the annular groove can be arbitrarily set to freely change the boost ratio and the change point of the boost ratio. By providing at least in the vicinity of the outer periphery of the axial contact surface of the rod with the reaction disc, the axial contact surface of the reaction case integrally provided with the input rod with the reaction disc can be easily cut by cutting, and The boost ratio and the change point of the boost ratio can be changed at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view of a negative pressure type booster according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view around the reaction disc of FIG.

FIG. 3 is a diagram showing a relationship between an input and an output of the negative pressure type booster of the first embodiment.

FIG. 4 is a sectional view of a negative pressure type booster according to a second embodiment of the present invention.

[Explanation of symbols]

 10 ... Housing 14, 15 ... Movable wall 41 ... Input rod 42 ... Air valve 43 ... Output rod 151 ... Power piston 151f ... Reaction case (second embodiment) 151g. .. Annular groove (second embodiment) 432 ... Reaction disk 431 ... Cup portion of output rod 431a ... Annular groove (first embodiment) Ra1, Rb1 ... Transformer chamber Ra2, Rb2 ...・ Constant pressure chamber

Claims (2)

[Claims] 1. A housing, a constant pressure chamber that is located in the housing and is kept at a constant pressure inside the housing, and is selectively communicated with at least a high pressure source higher than the constant pressure chamber or the constant pressure chamber. A power piston that is partitioned into a variable pressure chamber, an air valve that slides axially through the power piston and the axial hole of the power piston, and the power piston and the air valve that can come into contact with the power piston and are always attached in a direction that comes into contact with both. A control valve configured to include an energized control valve and selectively communicating the variable pressure chamber with the high pressure source or the constant pressure chamber, and an input connected to the air valve for operating the control valve. The rod and the transmission of the propulsive force generated in the power piston due to the pressure difference between the constant pressure chamber and the variable pressure chamber from the power piston to the output rod. In a differential pressure type booster including a reaction disk for applying a reaction force to the air valve, an annular groove provided at least near an outer periphery of an axial contact surface of the output rod with the reaction disk is provided. The characteristic differential pressure type booster. 2. A housing, a constant pressure chamber which is located in the housing and is constantly kept at a constant pressure in the housing, and selectively communicates with at least a high pressure source higher than the constant pressure chamber or the constant pressure chamber. A power piston that is partitioned into a variable pressure chamber, an air valve that slides in the power piston and the power piston in the axial direction, is capable of contacting the power piston and the air valve, and is always urged in a direction of contacting both. A control valve which is composed of a control valve and which selectively communicates the variable pressure chamber with the high pressure source or the constant pressure chamber; and an input rod connected to the air valve for operating the control valve, The propelling force generated in the power piston due to the pressure difference between the constant pressure chamber and the variable pressure chamber is transmitted from the power piston to the output rod and In a differential pressure type booster including a reaction disc that applies a reaction force to the valve, an annular groove provided at least near the outer periphery of the axial contact surface of the power piston with the reaction disc is provided. Differential pressure type booster.