JPH043900Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial field of application The present invention provides a piston for a negative pressure booster, in particular, a disk portion superimposed on a piston diaphragm, and a center portion of this disk portion. The present invention relates to an improvement in a device in which a connecting flange, which is divided into a penetrating boss portion and a connecting flange formed integrally with the boss portion and abuts one side of the disk portion, is connected to the disk portion via a connecting member.

(2) Prior Art Conventionally, in such a booster piston, the connecting member is formed from a steel plate (for example, in
(See Publication No. 67248).

(3) Problems to be solved by the invention However, since the steel plate connecting member has relatively high rigidity, when the disc part bends due to a large pressure difference between the front and rear parts, the connection between the disc part and the connecting member There is a risk that concentrated stress will occur in the abutting portion, which may impair the durability of the disc portion.

The present invention was developed in view of the above circumstances, and an object of the present invention is to provide a booster piston that does not generate concentrated stress in the disk portion even if the disk portion is bent due to a pressure difference, and has high durability. do.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention consists of a disk portion that overlaps the piston diaphragm on the back side, and a boss that passes through the center of this disk portion. divided into parts,
A booster piston for a negative pressure booster, comprising a connecting flange integrally formed with the boss portion and abutting against the front surface of the disk portion, connected to the disk portion via a connecting member. A connecting member consisting of a pair of presser bars that cross the front surface of the presser bars with the axis line in between, a pair of hinge pins formed by bending one end of each of the presser bars, and a connecting rod that connects the other ends of the presser bars to each other. The hinge pins are formed of a single piece of elastic steel wire, and both the hinge pins are inserted into a pair of pin bosses cut and raised on the front surface of the disc part, while the connecting rod is fixed to the disc part by a fixing member. It is characterized in that the presser bar is pressed against the front surface of the boss portion while being bent.

(2) Effect When the disk portion of the booster piston bends due to the pressure difference between the front and rear sides, the connecting member made of steel wire can also bend together with the disk portion, and therefore the connecting member of the disk portion and It is possible to avoid the occurrence of concentrated stress at the abutting part. Moreover, since the presser rod of the connecting member is crimped to the front surface of the boss part due to its bending elasticity,
Even when the disc part is deformed, no gap is created between the boss part and the presser bar, and therefore no hitting sound is generated even when the disc part is deformed and restored.

A small assembly of the disc part and the connecting member can be configured in advance by inserting the hinge pin of the connecting member into the hinge boss of the disc part. Therefore, when assembling the booster piston, after fitting the boss into the disk,
The boss portion can be connected to the disk portion simply by rotating the connecting member toward the boss portion around the hinge pin and fixing the connecting rod to the disk portion using the fixing member.

(3) Embodiment Below, an embodiment of the present invention will be explained with reference to the drawings. In FIG. The interior is composed of
A booster piston 2 is housed in the booster piston 2 so as to be able to reciprocate back and forth, and a piston diaphragm 3 is attached to the rear surface of the booster piston 2.
It is divided into a working chamber B. The first working chamber A is always in communication with a negative pressure source, for example, an intake manifold (not shown) of an internal combustion engine, through a negative pressure introduction pipe 4, and
The working chamber B is alternately controlled to communicate with the first working chamber A or an atmospheric air inlet 6, which will be described later, via the control valve 5.

The booster piston 2 is always urged in the backward direction, that is, toward the second working chamber B, by a return spring 7 contracted in the first working chamber A, and its backward limit is set by a plurality of bumps formed on the back surface of the piston diaphragm 3. Convex part 3
a is regulated by contacting the rear wall of the booster shell 1.

The booster piston 2 is provided with a valve cylinder 8 that protrudes in the axial direction from the rear surface of the boss portion 2b, a valve body holding cylinder 9 is fitted into the rear part of the valve cylinder 8, and the rear end is connected to the atmosphere inlet 6. A flexible filter 10 is installed to filter the introduced air.

The valve cylinder 8 is slidably supported by an extension cylinder 1a extending rearward from the rear wall of the booster shell 1 via a flat bearing 11 and a seal member 12. Within this valve cylinder 8, the control valve 5 is configured as follows.

That is, a cylinder hole 15 is formed in the front inner wall of the valve cylinder 8.
and an annular first valve seat 1 surrounding the rear opening thereof.
6 ₁ is formed, and a valve piston 18 constituting a front end portion of an input rod 17 operated by the brake pedal P is slid into the cylinder hole 15 . A second valve seat 16 ₂ surrounded by a first valve seat 16 ₁ is formed at the rear end of the valve piston 18 .

Further, a base end portion 19a of a cylindrical valve body 19 with both ends open is clamped on the inner wall of the valve cylinder 8 via the valve body holding cylinder 9. This valve body 19 is molded from an elastic material such as rubber, and has a thin intermediate portion 19b extending radially inward from its base end 19a, and a thick valve at the inner peripheral end of the intermediate portion 19b. The valve portion 19c is connected to the first and second valve seats 1.
6 ₁ and 16 ₂ are arranged opposite to each other. Thus, the valve portion 19c can be moved back and forth by deforming the intermediate portion 19b.

An annular reinforcing plate 20 is embedded in the valve portion 19c,
A valve spring 21 is pressed against this to urge the valve portion 19c toward both valve seats 16 ₁ and 16 ₂ .

The outer part of the first valve seat ₁₆₁ is the booster piston 2
The middle part of the first and second valve seats is connected to the second working chamber A through another through hole 23.
The working chamber B and the inner side of the second valve seat 16 ₂ are always in communication with the atmosphere inlet 6 via the intermediate portion of the valve body 19 .

A return spring 25 is provided between the valve body holding cylinder 9 and a spring seat body 24 fixed to the input rod 17 to urge the input rod 17 in the backward direction.

Further, in the booster piston 2, an output rod 27 passing through the front wall of the booster shell 1 is connected to a reaction mechanism 26.
connected via. The reaction mechanism 26 is of a known type and transmits the reaction force of the output rod 17 to the valve piston 18 and therefore to the input rod 17, so that it can be sensed by the operator.

The output rod 27 is connected to the rear end of a piston 28 to operate a brake master cylinder M mounted on the front surface of the booster shell 1.

The booster piston 2 is divided into a disk portion 2a and a boss portion 2b that passes through the center of the disk portion 2a, and the disk portion 2a is formed from a steel plate and protrudes from the boss portion 2b and the rear surface. The valve cylinder 8 is integrally molded from synthetic resin.

A connecting flange 29 that contacts the front surface of the disk portion 2a is integrally formed on the boss portion 2b, and this connecting flange 29 is connected to the disk portion 2a by a connecting member 30.

As shown in FIG. 2, the connecting member 30 is made by bending an elastic steel wire, and includes a pair of presser bars 31, 31 facing each other with a gap therebetween, and one end of these presser bars 31, 31. It has a pair of hinge pins 32, 32 bent inward from each other, and a connecting rod 33 that connects the other ends of the presser bars 31, 31. At the center of each of the presser rods 31, 31, there is a pin concentric with the booster piston 2. arc-shaped guide portions 31a, 31a are formed,
Further, a semicircular portion 33a is formed in the center of the connecting rod 33 and is curved outwardly.

Thus, the hinge pins 32, 32 are connected to the disk portion 2a.
A pair of hinge bosses 34, 3 cut and raised on the front side of the
4 from the outside, each tip 34a, 34a
is bent to prevent it from coming out, and then the presser rods 31, 3
1 is rotated so as to come into contact with the connecting flange 29, and the bolt 35 installed upright on the front surface of the disc part 2a is inserted into the semicircular part 33a of the connecting rod 33, and the bolt 35 penetrates and connects. The connecting rod 33 is fixed to the disk portion 2a by a presser plate 36 superimposed on the rod 33 and a nut 37 screwed onto the bolt 35. In this way, the connecting member 30 presses the connecting flange against the disk portion 2a by the bending elasticity of the presser bars 31, 31,
Both 2a, 2a are integrally connected.

The front surface of the connecting flange 29 supports the rear end of the return spring 7. At that time, the rear end of the return spring 7 is connected to the presser bars 31, 31 in order to prevent the return spring 7 from moving inadvertently.
The guide portions 31a, 31a are engaged with each other inside.

On the other hand, an annular locking portion 38 having a hook-shaped cross section is formed on the inner peripheral edge of the disc portion 2a, and the inner peripheral bead 3b of the piston diaphragm 3 is locked to this locking portion 38. 3b is a locking portion 38
It is closely attached to the boss portion 2b to prevent it from coming off.

In FIG. 1, 40 is a dustproof boot stretched between the rear extension tube 1a and the valve body holding tube 9, and 41 is a dash board of the automobile body that supports the booster shell 1.

Next, to explain the operation of this embodiment, FIG. 1 shows the inoperative state of the booster S, and the input rod 1 is
7 and the booster piston 2 are held in predetermined retracted positions by the elastic forces of the return springs 25 and 7, respectively, and the valve piston 18 uses the elastic force of the return spring 25 to move the second valve seat 16 ₂ to the front surface of the valve portion 19c. and is spaced apart from the first valve seat 16 ₁ to form a gap g therebetween. Therefore, the first working chamber A, which constantly stores negative pressure, is connected to the through hole 2.
2. Second working chamber B via gap g and through hole 23
Since the front opening of the valve portion 19c is closed by the second valve seat ₁₆₂ , the negative pressure in the first working chamber A is transmitted to the second working chamber B, and both working chambers A and B are in communication with each other.
The air pressure is balanced and the booster piston 2 is under the control of the return spring 7.

Now, when the brake pedal P is depressed to brake the vehicle and the input rod 17 and the valve piston 18 are moved forward, the valve portion 19c, which is urged forward by the valve spring 21, moves forward following the valve piston 18. Immediately, the first valve seat 16 ₁ seats on the first valve seat 16 1 to cut off the communication between the working chambers A and B, and at the same time the second valve seat 16 ₂ seats on the valve portion 19 .
The second working chamber B is communicated with the atmosphere inlet 6 through the through hole 23 and the inside of the valve body 19, apart from the second working chamber B. Therefore, the atmosphere is quickly introduced into the second working chamber B, and the pressure in this chamber B becomes higher than that in the first working chamber A, and the pressure difference between the two chambers A and B causes the booster piston 2 to return to the spring 7. Since the output rod 27 is moved forward through the reaction mechanism 26, the brake master cylinder M is operated and the vehicle is braked.

In this way, when the booster piston 2 operates due to the pressure difference between the working chambers A and B, even if the disc portion 2a is bent due to the pressure difference, the connecting member 30 made of steel wire is also bent. , disc part 2a
No concentrated stress is generated at the contact portion with the connecting member 30. Moreover, the presser rod 31 of the connecting member 30,
31 is crimped to the front surface of the boss portion 2b due to its bending elasticity, even when the disk portion 2a is deformed, there is no gap between the boss portion 2b and the presser bars 31, 31, and therefore the disk Even when the portion 2a is deformed and restored, no tapping sound is generated between the boss portion 2b and the presser bars 31, 31.

Next, when the depression force of the brake pedal P is released, the input rod 17 is moved backward by the elastic force of the return spring 25 applied to the valve piston 18, thereby seating the second valve seat ₁₆₂ on the valve portion 19c and ,
Separate the valve portion 19c from the first valve seat ₁₆₁ ,
Since a gap g is again formed between them, the air pressures in both working chambers A and B are quickly balanced through the gap g, and when the pressure difference between them disappears, the booster piston 2 is activated by the elastic force of the return spring 7. retreat by force.

By the way, in the booster piston 2, the connecting member 30 is attached to the hinge bosses 34, 34 of the disc portion 2a.
By inserting the hinge pins 32, 32,
A subassembly of the disk portion 2a and the connecting member 30 can be configured in advance. Therefore, when assembling the booster piston 2, after fitting the boss part 2b into the disc part 2a, the connecting member 30 is rotated toward the boss part 2b about the hinge pins 32, 32, and the fixing member allows
That is, the boss portion 2b can be fixed to the disk portion 2a by an extremely simple operation of fixing the connecting rod 33 to the disk portion 2a using the bolt 35, the presser plate 36, and the nut 37.

C. Effects of the invention As described above, according to the invention, a pair of presser bars that cross the front surface of the boss part with the axis line interposed therebetween, a pair of hinge pins formed by bending one end of each of the presser bars, and both presser bars are provided. A connecting member consisting of a connecting rod that connects the other ends of the rods is formed from a single elastic steel wire, and both hinge pins are inserted into a pair of pin bosses cut and raised on the front surface of the disc part, while the connecting rod is It is fixed to the disc part by the fixing member and is crimped to the front surface of the boss part while bending the presser bar, so when the pressure difference acts on the booster piston, the connecting member is bent together with the disc part, and the disc part is flexed. It is possible to avoid the occurrence of concentrated stress at the abutting portion of the disk portion with the connecting member, and the durability of the disk portion is improved. Moreover, since the presser rod of the connecting member is crimped to the front surface of the boss part due to its bending elasticity, the crimped state can be maintained even when the disc part is deformed, thereby preventing the generation of gaps that cause hitting noises. I can do it. Moreover, since the connecting member is constructed by bending a single steel wire, it can be obtained at extremely low cost. In addition, since the hinge pin of the connecting member can be inserted into the hinge boss of the disc part and a small assembly of the disc part and the connecting member can be configured in advance, the booster piston can be easily assembled. It is also possible to prevent loss of connecting members during disassembly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical sectional side view of a negative pressure booster equipped with a booster piston of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. 1. S... Negative pressure booster, 2... Booster piston, 2a... Disc part, 2b... Boss part, 3... Piston diaphragm, 29... Connection flange, 3
0... Connection member, 31... Presser bar, 32... Hinge pin, 34... Hinge boss, 35, 36, 37
...Bolts, holding plates, and nuts as fixing members.

Claims (1)

[Claims for Utility Model Registration] The piston diaphragm 3 is divided into a disk portion 2a superimposed on the back surface and a boss portion 2b passing through the center of the disk portion 2a, and formed integrally with the boss portion 2b. This is a booster piston for a negative pressure booster, in which a connecting flange 29 that is connected to the front surface of the disc part 2a is connected to the disc part 2a via a connecting member 30, and the axis of the boss part 2b is It consists of a pair of presser bars 31 that sandwich and cross the front surface thereof, a pair of hinge pins 32 formed by bending one end of each of the presser bars 31, and a connecting rod 33 that connects the other ends of the presser bars 31 to each other. The connecting member 30 is formed of a single elastic steel wire, and both the hinge pins 32 are inserted into a pair of pin bosses 24 cut and raised on the front surface of the disc portion 2a, while the connecting rod 33 is inserted into the fixing members 35 to 37.
The presser rod 3 is fixed to the disk portion 2a by
A booster piston for a negative pressure booster, characterized in that a piston 1 is bent and crimped onto the front surface of the boss portion 2b.