FR2468777A1 - PNEUMATIC SERVO-SURPRESSOR - Google Patents

Abstract

Disclosed is a pneumatic booster including a housing formed by facing and connecting the respective open end portions of generally cup-shaped front and rear casings, with a flexible membrane separating the interior of the housing into chambers. front and rear, the circumference of the membrane being tightly clamped between the open end parts of the envelopes. According to the invention, first and second retaining portions 7, 8 protruding radially inwardly, are formed on the open end portion of the casing 1, and they are spaced forward and backward, and a flange 2a is formed at the open end of the envelope 2 and is placed between the first and second retaining portions to thereby prevent the relative movement of the envelopes 1, 2 forward and backward. The invention applies in particular to braking systems.

Description

The present invention relates to a servo

  pneumatic booster for use in a braking system of a vehicle and, more particularly, to a pneumatic booster-type booster having a housing formed by disposing face to face and connecting the open end portions of front and rear envelopes generally cutting shape, with a flexible membrane separating the interior of the housing into the front and rear chambers, and the outer circumference of which is sealed between the open end portions

envelopes.

  The pneumatic servo-booster of the above kind

  thereon further comprises a valve mechanism for controlling the pressure difference between the front and rear chambers, an input shaft actuating the valve mechanism, a power piston connected to the diaphragm and receiving a differential pressure force acting through the membrane, and an output shaft connected to the piston. The housing receives the force produced by the pressure difference between the front and rear chambers, the reaction force of the output shaft and the force acting on the related parts such as the master cylinder attached to the front casing, and , the front and rear envelopes must be rigidly connected to prevent relative forward movement

and backwards.

  Traditionally, the open end portion of each envelope is enlarged to define a radial step which faces an end portion flange or flange of the other envelope, to thereby restrict the relative movement of envelopes in the approach direction. Relative displacement in the separation direction is prevented by radially inserting a protuberance formed on the outer circumference of the flanged or flanged end portion of the other envelope into a retaining aperture formed in the

  part of increased diameter of the first envelope.

  However, a pneumatic servo-booster is usually installed in a small space in an engine compartment of the vehicle, so it is not advantageous to increase the total diameter of the housing.

  The present invention relates to a servo

  pneumatic booster to avoid inconvenience

  described above and, according to the invention, the

  first and second retaining parts making radial-

  the inward end portion of the front and rear envelopes, which retaining portions are spaced from each other in a forward and a rearward direction, and a flange or flange is formed at the open end portion of the other envelope and is placed between the first and second retention portions, to prevent relative movement of the envelopes to

forward and backward.

  The invention will be better understood and other purposes, features, details and advantages thereof

  will appear more clearly in the description

  explanatory text which follows will refer to several illustrative drawings several embodiments of

the invention and in which:

  - Figure 1 shows a side view in partial section of a pneumatic servo-compressor according to the invention; FIG. 2 is a partial and enlarged perspective view of a front casing of the servo-booster of FIG. 1; Figure 3 is a partial and enlarged view of a portion of Figure 1 which is surrounded by a circle, and Figure 4 is a view similar to Figure 3;

but showing a modified form.

  The pneumatic booster-booster illustrated in FIG. 1 comprises a housing 3 consisting of a front casing 1 and a rear casing 2. A flexible and annular membrane 4 divides the inside of the casing 3 into a front chamber 5 and a rear chamber 6. The front and back wraps 1 and 2 are generally cup-shaped, and the open end portions of the cups are disposed thereof, and are in sealing relationship with the circumferential portion.

  outer membrane 4 which is clamped together.

  Figures 2 and 3 show the connection between the front and rear envelopes. 1 and 2. On the open end (the right-hand end facing the drawings) of the front casing 1 are provided first and second retaining portions 7 and 8 spaced in the front and rear direction (transverse direction in the drawings) and in the circumferential direction and protruding radially inwards. In the drawings, short cut-off lines 9, 10 and 11 are formed in the front casing 1 to extend respectively in the circumferential direction of the front casing 1, and are spaced apart from one another by direction forward and backward, and radially inwardly deforming the portions defined between the lines 9 and 10, are formed the first retaining portions 7, the second retaining portions 8 being formed by deforming radially towards inside the parts defined between the lines 11 and the open end of the front casing 1. An annular flange Za extending radially outwardly is provided on the rear casing 2 and the thickness of the casing

  flange 2a corresponds to the space between lines 10 and 11.

  The front and rear envelopes 1 and 2 are connected to each other by inserting the annular flange 2.a of the rear envelope 2 in the space between the first and second retaining portions 7 and 8, thus the relative displacement between the first and second envelopes. forward direction

and backward is prevented.

  Preferably, the annular flange 2a is formed at the rear end of a rearwardly extending curved and annular portion 2b, which is formed on the open end portion of the back shell 2 as shown in FIG. FIG. 3. An annular and thick portion 4a of the membrane 4 is tightly sealed between the front casing 1 and the recumbent portion 2.b of

the back envelope 2.

  In this embodiment, a plurality of first and second retaining portions 7 and 8 are formed on the outer casing 1 as can be seen in FIG. 1, which are spaced in the circumferential direction of the front casing 1 and which are in alignment with each other in the forward and backward direction, but the first and second retaining portions may be offset circumferentially. The pneumatic booster-booster of FIG. 1 is and a conventional type and it further comprises an input shaft 12, an output shaft 13 and traditional internal elements (not shown) such as a valve mechanism actuated by the shaft 12 to control the pressure difference between the front and rear chambers 5 and 6, and a piston associated with the membrane 4 to receive the pressure difference force and

  transmit the output force to the output shaft 13.

  However, the detailed explanation in relation to the construction of the internal elements and their function is omitted. FIG. 4 shows a modified form, where a first holding portion 7 'is defined by a part making

  radially inward projection formed on the casing

  loppe before 1 and a second holding portion 8 'is

  formed by radially inwardly deforming the

  In this embodiment, the first retaining portion 7 'is annular so as to extend over the entire circumference of the front casing 1 and is formed by a process of forming the casing. a bead, and a number of circumferentially spaced second retention portions

  8 'are formed for example by a process of discovery.

  page and bending, however the two retaining portions 7 'and 8' may have an annular shape or

  a circumferentially spaced arrangement.

  Alternatively, the first and second retaining portions may be formed on the back shell

2.

  As described above, the diameter of the housing can be reduced according to the invention, and the front and rear envelopes. can be connected

  easily and reliably to each other.

  Of course, the invention is not limited to the embodiments described and shown which have been given by way of example. In particular, it includes all means constituting equivalents

  techniques of the means described, as well as their

  if executed in accordance with his spirit and implemented in the context of the protection

as claimed.

Claims (2)

R E V E N D I C A T I 0 N S CLAIMS   A pneumatic servo-booster of the type comprising a housing formed by disposing face-to-face and connecting the respective open end portions of front and rear envelopes generally cup-shaped, and a flexible membrane separating the interior of said housing into front chambers. and rear, the outer circumference of said membrane being tightly sealed between the open end portions of the front envelopes. and rearward, characterized in that first and second (7,8) radially inwardly projecting retaining portions are formed on the open end portion of the front or rear casing, said first and second retaining portions being spaced forwards and backwards, and in that a flange (2a) is formed on the open end portion of the other envelope (2) and is placed between the first and second retaining portions, afon d thus prevent relative displacement   said envelopes (1,2) forward and rearward.   2. Pneumatic pressure booster according to claim   cation 1 characterized in that a number of groups of first, second and third circumferentially spaced and circumferentially extending cutouts 9, 10 and 11 are formed in the outer end portion of one of the front or rear envelopes, said respective groups being circumferentially spaced; and in that portions defined between first and second cuts   are radially inwardly deformed to   killing the first retaining portions (7) above, and parts defined between the third cutouts and the open end of the first envelope (1) above are deformed radially inward to form   the second holding portion (8) above.