JPH0550916A - Booster - Google Patents

Abstract

PURPOSE:To simplify jumping quantity regulating work by providing at least either of abutting faces where the basic part of an output shaft and a reaction disc abut mutually with a recess, and accommodating a shim in the recess to regulate the size of the inside space of the recess. CONSTITUTION:In a brake booster, a valve plunger 2 connected with an input shaft is fittedly inserted in a through hole drilledly provided in a valve body 1, and the right inner periphery of a recess 4a provided on the basic part of an output shaft 4 is slidably fitted on the outer periphery of an annular projection 1b provided at the left end of the through hole 1a of the valve body 1. A reaction disc 3 is accommodated in the recess 4a. In this case, a circular recess 4b is formed on the axial part of the bottom of the recess 4a, and plural thin plate-shaped shims 5 are accommodated in the recess 4b for regulating the size of the inside space of the recess 4b. Thus rapid increase in output caused by abutting of the valve plunger 2 onto the disc 3, namely dispersion in jumping quantity, can be regulated.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster, and more particularly to improvement of a booster capable of adjusting a so-called jumping amount.

2. Description of the Related Art Conventionally, as a booster, an output shaft having one end serving as a base portion slidably provided on a valve body and a tip end portion of the output shaft slidably fitted in a through hole of the valve body. Of the valve plunger facing the base of the output shaft, and a reaction disc provided between the base of the output shaft and the tip of the valve plunger to transmit the reaction force of the output acting on the output shaft to the input shaft via the valve plunger. It is known that a gap is formed between the reaction disc and the tip of the valve plunger in the non-operating state (for example, Japanese Utility Model Laid-Open No. 57-88660). In such a conventional booster, the reaction disk elastically deformed as the input shaft moves forward comes into contact with the tip of the valve plunger to obtain an output of a predetermined servo ratio. The sudden increase in output at the time when the reaction disc and the valve plunger come into contact with each other is generally called jumping.

By the way, conventionally, when the clearance between the reaction disk and the valve plunger in the non-actuated state is different, the jumping amount described above varies. Therefore, the jumping amount varies when assembling the booster. I try to adjust it so that it doesn't exist. In the conventional booster described above, an annular shim is interposed between the rear end face of the reaction disc and the end face of the valve body in order to adjust the variation in the jumping amount. By interposing the shim in this way, the variation in the gap between the reaction disc and the tip of the valve plunger is adjusted so that the variation in the jumping amount does not occur. As described above, in the conventional booster, since the shim is provided on the side where the servo ratio is determined, that is, between the reaction disc and the end surface of the valve body, the inner diameter of the annular shim is the outer diameter of the tip of the valve plunger. Had to be set to the same. Therefore, when the servo ratio of the booster is different, it is necessary to prepare a shim with a different inner diameter for each booster with a different servo ratio, so the number of types of shims increases and the work of adjusting the jumping amount is complicated. There was a drawback that

[Means for Solving the Problems] In view of such circumstances,
The present invention relates to an output shaft having one end serving as a base portion slidably provided on a valve body, and a valve plunger slidably fitted in a through hole of the valve body so that a tip end faces the base portion of the output shaft. And a reaction disc that is provided between the base of the output shaft and the tip of the valve plunger and transmits the reaction force of the output acting on the output shaft to the input shaft via the valve plunger. In a booster in which a gap is formed between the tip of the plunger and the reaction disc, a recess is provided in at least one of the contact surfaces where the base of the output shaft and the reaction disc contact each other, and The size of the internal space of the recess can be adjusted by accommodating the shim in the recess.

According to this structure, the jumping amount can be adjusted by increasing or decreasing the number of shims to change the size of the internal space of the recess. And
Since the recess for accommodating the shim is provided on the side opposite to the side on which the servo ratio is determined, basically only one type of shim for accommodating the recess needs to be prepared according to the inner diameter of the recess. . Therefore, the adjustment work of the jumping amount can be simplified as compared with the related art in which different types of shims are required.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a main part in a shell of a brake booster. In FIG. 1, reference numeral 1 is slidably provided in the shell. It is a valve body. A through hole 1a is formed in the shaft portion of the valve body 1, and a valve plunger 2 forming a part of a valve mechanism is slidably fitted in the through hole 1a. The right end of the valve plunger 2 is connected to an input shaft (not shown), and the left end of the valve plunger 2 faces the right end surface 3a of the reaction disc 3. An annular protrusion 1b is provided at the left end of the through hole 1a of the valve body 1, and an outer peripheral portion of the annular protrusion 1b has a right inner periphery of a concave portion 4a provided at the base of the output shaft 4. The parts are slidably fitted together. The reaction disc 3 having a substantially disk shape is housed in the recess 4a of the output shaft 4, and the reaction disc 3 is axially sandwiched between the recess 4a and the tip surface of the annular projection 1b of the valve body 1. .. The left end of the output shaft 4 is interlocked with the piston of a master cylinder (not shown). In the non-actuated state of the booster shown in FIG. 1, a slight gap is maintained between the right end face 3a of the reaction disc 3 and the tip end face of the valve plunger 2 in the opposed state. The above configuration and the operation based on it are the same as those of the conventionally known booster. Therefore, in this embodiment, a circular concave portion 4b is formed in the shaft portion of the bottom surface of the concave portion 4a that abuts on the end surface 3b on the left side of the reaction disc 3, and the concave portion 4 is formed.
A circular, thin plate-shaped shim 5 is accommodated in the inside of b in accordance with its inner diameter. Thus, the recess 4b
By accommodating a plurality of thin plate-shaped shims 5 therein, the size of the internal space of the recess 4b is adjusted. As a result, when the valve plunger 2 is moved to the left as the input shaft (not shown) moves forward, a sharp output increase at the time when the right end surface 3a of the reaction disc 3 contacts the tip surface of the valve plunger 2, that is, It is possible to adjust the variation in the jumping amount. Further, in the present embodiment, since the concave portion 4b for accommodating the shim 5 is provided on the side opposite to the side where the servo ratio is determined, the concave portion 4b is formed.
Basically, only one type of shim 5 to be accommodated in the recess 4b may be prepared according to the inner diameter of the recess 4b. Therefore, according to the present embodiment, the jumping amount adjustment work can be simplified as compared with the conventional one in which different types of shims need to be prepared for each booster having a different servo ratio. In addition, in this embodiment, the reaction disk 3 is used.
The outer peripheral edge of the end surface 3b on the left side in is greatly chamfered, and therefore, the outer shape of the reaction disk 3 is a truncated cone shape that is short in the axial direction. Further, the concave portion 4a of the output shaft 4 for accommodating the reaction disc 3 is formed according to the outer shape of the reaction disc 3, and the entire base portion of the output shaft 4 provided with the concave portion 4a is also frustoconical. Further, the base of the output shaft 4 is the annular protrusion 1b.
6a of the retainer 6 for preventing the retainer 6 from falling off
Is brought into contact with the stepped end surface 1c of the valve body located on the left side of the tip end surface of the annular projection 1b.
Since the base portion of the output shaft 4 is frustoconical as described above, the tubular portion on the right side of the base portion of the output shaft 4 is positioned on the right side of the base portion 6a of the retainer 6. , They are substantially radially overlapping. Therefore, in comparison with the case where the retainer 106 covers the entire base of the output shaft 4 as in the embodiment shown in FIG. 2 described later, the recess 4 a of the output shaft 4 is compared.
It is possible to increase the outer diameter of the reaction disc 3 housed in. (Second Embodiment) FIG. 2 shows a second embodiment of the present invention. In the second embodiment, the recess 104b of the output shaft 4 for accommodating the shim 105 is a stepped recess and the shim 105 is formed in an annular shape, which is on the right side of the stepped recess 104b. The shim 105 is stored in the large diameter portion. In the second embodiment, the retainer 106 covers the entire base of the output shaft 4, and the base 106a of the retainer 106 contacts the step end surface 101c on the right side of the tip end surface of the annular projection 101b. I try to contact them. The other structure is basically the same as that of the first embodiment. Even with such a configuration of the second embodiment, it is possible to obtain the same operational effect as that of the first embodiment described above. In both of the above embodiments, the shims 5, 1
The recesses 4b and 104b for housing the output shaft 05 are
Although it is formed on the 104 side, the following configuration may be used. That is, a recess may be formed in the shaft portion of the left end surfaces 3b and 103b of the reaction discs 3 and 103, and the shim may be housed in the recess.

As described above, according to the present invention, it is possible to obtain an effect that the adjustment work of the jumping amount can be simplified as compared with the conventional case.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

1, 101 Valve body 2, 102 Valve plunger 3, 103 Reaction disc 4, 104 Output shaft 4b, 104b Recess 5,105 Shim

Claims (1)

[Claims] 1. An output shaft having one end serving as a base portion slidably provided on a valve body, and a valve having a tip end opposed to a base portion of the output shaft slidably fitted in a through hole of the valve body. A plunger and a reaction disc that is provided between the base of the output shaft and the tip of the valve plunger and transmits the reaction force of the output acting on the output shaft to the input shaft via the valve plunger. In a booster configured to form a gap between the tip of a valve plunger and a reaction disc, a recess is provided on at least one of the contact surfaces where the base of the output shaft and the reaction disc contact each other, and A booster, wherein a shim is housed in the recess so that the size of the internal space of the recess can be adjusted.