JPH0437014Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field The present invention relates to a connection structure between a diaphragm and a valve cylinder in a negative pressure booster that boosts the brake master cylinder of an automobile with negative pressure. In particular, the present invention relates to an improvement in a structure in which a diaphragm and a valve cylinder passing through a center hole of the diaphragm are connected using a chrysanthemum washer.

(2) Conventional technology Such a conventional connection structure is known, for example, from Utility Model Application Publication No.
As disclosed in Japanese Patent No. 69068, the inner peripheral bead of the diaphragm that is fixed to the outer periphery of the valve cylinder is pressed and fixed with a chrysanthemum washer attached to a step formed on the outer periphery of the valve cylinder. There is.

(3) Problems to be solved by the invention However, in the conventional connection structure described above, when the valve cylinder is moved by stepping on the brake pedal during non-servo mode when the negative pressure in the negative pressure chamber has disappeared, the diaphragm fixed to the valve cylinder is moved. The inner bead was pressed against the side of the chrysanthemum washer, and there was a risk that the diaphragm would come off the valve cylinder or that the inner bead of the diaphragm or the chrysanthemum washer would be damaged.

The present invention has been made in view of the above circumstances, and provides the above-mentioned connection structure that can prevent the inner bead of the diaphragm from coming off and also prevent damage to the inner bead and the chrysanthemum washer. The purpose is to

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention provides a negative pressure booster in which the inner peripheral bead of the diaphragm is locked to the outer periphery of the valve cylinder and fixed with a chrysanthemum washer. A cover having a connecting structure for a diaphragm and a valve cylinder, in which a protrusion is formed on the inner periphery of a ring-shaped plate body radially inward, and a flange is provided on the outer periphery of the plate body protruding axially. a plate, and a groove formed on the outer periphery of the valve cylinder so that the protrusion of the cover plate can engage, the cover plate being eccentrically inserted into the valve cylinder and brought into contact with the inner peripheral bead of the diaphragm. After that, the cover plate is coaxially aligned with the valve cylinder and the chrysanthemum washer is installed between the flange of the cover plate and the valve cylinder with the protrusion engaged in the groove.

(2) Effect In the above configuration, when connecting the diaphragm and the valve cylinder, first insert and lock the inner peripheral bead of the diaphragm into the valve cylinder, and then cover the valve cylinder with the inner bead eccentric to the valve cylinder. Insert the plate and bring the side surface of the cover plate into contact with the inner bead of the diaphragm that has already been inserted. Subsequently, by aligning the cover plate coaxially with the valve cylinder, the protrusion protruding on the inner periphery of the cover plate is engaged with the groove formed on the outer periphery of the valve cylinder, thereby preventing the cover plate from moving in the axial direction. regulate. Next, the chrysanthemum washer inserted into the valve cylinder is installed between the flange protruding in the axial direction on the outer periphery of the cover plate and the valve cylinder, and the cover plate is placed concentrically with the valve cylinder so that the protrusion does not come out of the groove. Hold. As a result, even if the inner peripheral bead of the diaphragm is pressed toward the chrysanthemum washer, the load is supported by the cover plate, so the chrysanthemum bead is deformed and the diaphragm does not come off the valve cylinder, or it is pressed against the chrysanthemum washer. This prevents the inner peripheral bead of the diaphragm from being damaged by this.

(3) Examples Examples of the present invention will be described below with reference to the drawings.

First, in FIG. 1 showing an embodiment of the present invention,
The booster shell 1 of the negative pressure booster B includes a pair of front and rear shell halves 1a and 1b whose opposite ends are connected to each other.
A brake master cylinder M is attached to the front surface of the front shell half 1a, and the rear shell half 1b is fixed to a vehicle body (not shown).

The inside of the booster shell 1 is divided into a negative pressure chamber 4 on the front side and an operating chamber 5 on the rear side by a booster plate 2 accommodated therein so as to be able to reciprocate back and forth, and a diaphragm 3 superimposed on the rear surface. The negative pressure chamber 4 is connected to a negative pressure source (not shown) via a negative pressure introduction pipe 7. The outer peripheral bead 3a of the diaphragm 3 is sandwiched between the two shell halves 1a, 1b.

The booster plate 2 is made of a steel plate and is connected to a valve cylinder 6 passing through a center hole 2a thereof. Valve cylinder 6
is made of synthetic resin. A return spring 9 that biases the valve cylinder 6 in the backward direction (to the right in the figure) via the spring seat plate 8 is housed in the negative pressure chamber 4 .

The valve cylinder 6 is slidably supported via a bush 11 and a seal member 12 on a rear extension cylinder 10 that is integrally formed on the rear wall of the rear half shell 1b.

The inside of the valve cylinder 6 has a negative pressure chamber 4 and an operating chamber 5.
first and second ports 13, 1 respectively communicating with
4 is provided. Further, a control valve 15 is provided in the valve cylinder 6, whereby the second port 14 is alternately communicated with the first port 13 and the atmosphere inlet 16 opened in the end wall of the rear extension cylinder 10. It is becoming more and more common. The control valve 15 is of a known type and is operated by a brake pedal 18 via an input rod 17.

Further, the valve cylinder 6 is provided with an output rod 20 that projects forward and is connected to the piston 19 of the master cylinder M.

As shown in FIGS. 2 and 3, the valve cylinder 6 includes:
A connecting flange 21 is formed at the front end thereof, and an annular stepped portion 23 adjacent to the connecting flange 21 with an annular groove 22 in between is formed at the rear surface of the connecting flange 21 . The inner periphery of the booster plate 2 is bent in two stages to form a bent portion 2a, and this bent portion 2a is tightly fitted into an engagement groove 3c formed in an inner peripheral bead 3b of the diaphragm 3. The inner peripheral bead 3b of the diaphragm 3 and the booster plate 2, which are thus integrally connected, are connected to the connecting flange by the cover plate 24, which engages with the groove 22 and restricts the movement of the valve cylinder 6 in the axial direction. It is held under pressure between it and the rear surface of 21.

As is clear from FIGS. 4A and 4B, the cover plate 24 is composed of a ring-shaped plate, and a projection 24a is provided on a part of the inner periphery of the plate to protrude radially inward. At the same time, its outer periphery is bent in two steps to form a diaphragm holding flange 24b that projects forward and a diaphragm holding flange 24c that projects rearward. The cover plate 24 has its protrusion 24a inserted into the groove 22 of the valve cylinder 6.
In the engaged state, it is fixed by the chrysanthemum washer 25 installed between the chrysanthemum washer holding flange 24c and the stepped portion 23 of the valve cylinder 6.

By the way, as shown in FIG. 3, the valve cylinder 6 has a radius R ₁ at the large diameter portion behind the stepped portion 23, while the radius of the inner circumference of the cover plate 24 is
_R2 , the height of the protrusion 24a is L. Then, the protrusion 24a of the cover plate 24
The distance 2R ₂ -L from the inner end of the cover plate 24 to the opposing inner periphery with the center interposed therebetween is slightly larger than the outer diameter 2R ₁ of the valve cylinder 6. Therefore, if the cover plate 24 is made eccentric to the valve cylinder 6, the cover plate 24 can be moved eccentrically to the valve cylinder 6.
The protrusion 24a can be inserted into the groove 22 to engage the protrusion 24a. Furthermore, the radius R ₂ -L of the inner periphery of the protrusion 24a of the cover plate 24 is smaller than the radius R ₃ of the upper end of the groove 22 of the valve cylinder 6, so that the protrusion 24a of the cover plate 24 is temporarily When the cover plate 24 and the valve barrel 6 are coaxially aligned after being engaged with the groove 22 of the protrusion 2, the protrusion 2
4a remains engaged with groove 22.

Next, the operation of this embodiment will be explained.

Input rod 1 is activated by pressing the brake pedal 18.
7 moves forward (moves to the left in Figure 1), the working chamber 5
The second port 14 connected to
Communication with the first port 13 connected to the negative pressure chamber 4 is cut off and communication is established with the atmospheric air inlet 16, so that atmospheric pressure acts on the working chamber 5, causing the negative pressure chamber 4 and the working chamber 5 to
The booster plate 2 moves forward due to the pressure difference generated between the two, and the thrust is transmitted from the bottomed cylindrical portion 24 to the output rod 20 via the connecting flange 21, and further transmitted to the piston 19 of the master cylinder M to double the thrust. Can be power operated.

Next, release the brake pedal 18 and press the input rod 1.
7 is retracted, the second port 14 is connected to the control valve 1.
5 cuts off communication with the atmosphere inlet 16 and communicates with the first port 13, so both chambers 4,
5 decreases, and the force of the return spring 9 causes the valve cylinder 6 to retreat together with the booster plate 2.

By the way, when the negative pressure in the negative pressure chamber 4 is lost for some reason, the valve cylinder 6 is directly driven to the left in FIG. Since there is no pressure difference in the working chamber 5, the movement of the valve cylinder 6 causes the diaphragm 3 to deform in a direction away from the surface of the booster plate 2. However, since the inner peripheral bead 3a of the diaphragm 3 is in contact with the cover plate 24 that engages with the groove 22 of the valve cylinder 6, the load is distributed over the entire surface of the cover plate 24 and uniformly transmitted to the chrysanthemum washers 25. be done. As a result, Kikuwasushiya 25
This prevents the diaphragm 3 from being damaged due to torsion moment or bending moment, and also prevents the diaphragm 3 from coming off due to damage to the chrysanthemum washer 25. Further, the inner peripheral bead 3a of the diaphragm 3 is also prevented from being damaged because it comes into surface contact with the cover plate 24 and receives a uniform load. Since the movement of the inner peripheral bead 3b of the diaphragm 3 toward the outside in the radial direction is restricted, the diaphragm 3 is more reliably prevented from coming off the valve cylinder 6.

When connecting the diaphragm 3 and the valve cylinder 6 in such a negative pressure booster B, the cover plate 24 is inserted eccentrically with respect to the valve cylinder 6 as shown in FIG. is valve cylinder 6
When the position of the groove 22 is reached, the cover plate 24 is aligned concentrically with the valve barrel 6 and the protrusion 24a is engaged with the groove 22, as shown in FIG. 4B. From this state, the chrysanthemum washer 25 is engaged between the chrysanthemum washer retaining flange 22c formed on the outer periphery of the cover plate 24 and the stepped portion 23 of the valve cylinder 6, and as shown in FIGS.
As shown in the figure, the inner peripheral bead 3b of the diaphragm 3, which is integrally connected to the booster plate 2, is held between the connecting flange 21 of the valve cylinder 6 and the cover plate 24 under pressure. At this time, since the cover plate 24 is positioned concentrically with the valve cylinder 6 by the chrysanthemum washers 25, the engagement state between the protrusion 24a and the groove 22 is maintained, and the cover plate 24 is prevented from falling off.

In the above embodiment, the groove 22 is formed along the front circumference of the valve cylinder 6, but the groove 22 can be formed only in the portion of the cover plate 24 corresponding to the protrusion 24a.

C. Effects of the invention As described above, according to the invention, a protrusion is formed on the inner periphery of a ring-shaped plate radially inward, and a flange is provided protruding axially on the outer periphery of the plate. A cover plate is inserted into the outer periphery of the valve cylinder and brought into contact with the inner bead of the diaphragm, and a chrysanthemum washer is inserted between the flange and the valve cylinder with the protrusion engaged with the groove formed on the outer periphery of the valve cylinder. Since the cover plate is fixed by attaching the cover plate, the load applied to the inner peripheral bead of the diaphragm is distributed to the cover plate and is prevented from being directly transmitted to the chrysanthemum washer. This not only prevents the diaphragm from coming off the valve cylinder due to damage to the chrysanthemum washer, but also prevents the inner peripheral bead of the diaphragm from being pressed against the chrysanthemum washer and being damaged.

[Brief explanation of drawings]

Figures 1 to 4 show one embodiment of the present invention, in which Figure 1 is a vertical sectional side view of a negative pressure booster, Figure 2 is a sectional view taken along the line - - of Figure 1, and Figure 3 is a sectional view of a negative pressure booster. FIGS. 4A and 4B are enlarged cross-sectional views taken along the line -- in FIG. 1, showing the procedure for attaching the cover plate. 3...Diaphragm, 3a...Inner peripheral bead, 6
...Valve cylinder, 22...Groove, 24...Cover plate, 24a...Protrusion, 24c...Chrysanthemum lash holding flange (flange), 25...Chrysanthemum lash.

Claims (1)

[Scope of Claim for Utility Model Registration] A ring-shaped connection structure between a diaphragm and a valve cylinder in a negative pressure booster, in which the inner bead 3b of the diaphragm 3 is locked to the outer periphery of the valve cylinder 6 and fixed with a chrysanthemum bolt 25. A cover plate 24 has a protrusion 24a formed on the inner periphery of the plate body radially inward, and a flange 24c protruding axially on the outer periphery of the plate body, and a cover plate 24 formed on the outer periphery of the valve cylinder 6. and a groove 22 in which the protrusion 24a of the cover plate 24 can engage, and after the cover plate 24 is eccentrically inserted into the valve cylinder 6 and brought into contact with the inner peripheral bead 3b of the diaphragm 3, this cover plate 24
The protrusion 24 is aligned coaxially with the valve barrel 6.
With the chrysanthemum washers 2 engaged with the grooves 22
5 is installed between the 24 flange 24c of the cover plate and the valve cylinder 6, in a negative pressure booster, the diaphragm and the valve cylinder are connected to each other.