JPS6058067B2 - Negative pressure booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a negative pressure booster that boosts the brake master cylinder of an automobile using negative pressure, and in particular to a booster in which a booster shell made of synthetic resin is accommodated in the booster shell so as to be movable back and forth. The first pipe is connected to a negative pressure source by a piston.
When an input rod, which is divided into a working chamber and a second working chamber whose communication with the first working chamber or the atmosphere is selectively controlled via a control valve, and which is connected to the booster piston so as to be able to move back and forth, moves forward;
The input rod is connected to the control valve, and a tie rod passes through the booster piston between the front and rear walls of the booster shell so that a pressure difference for operating the booster piston accordingly is generated between the two working chambers. The present invention relates to an improvement in a negative pressure booster in which a sealing means is provided between the tie rod and the booster piston to allow the piston to operate.

The booster device transmits the forward thrust load received from the output side to the vehicle body via the tie rod, thereby avoiding the effect of that load on the booster shell. There is no need to provide high rigidity, and even if it is molded from a synthetic resin material, there is no problem in terms of strength, and it has the advantage of being lightweight.

The present invention provides the above booster in which the booster shell and the cover tube protruding from the rear surface of the booster piston and covering the valve tube housing the control valve are interconnected using the tie. , the number of parts in the connection part can be reduced and the structure can be simplified, and the entire booster including the cover tube and tie rod can be assembled into a single completed unit before being assembled on the car body. The purpose is to be able to be assembled independently of the vehicle and to simplify handling during inspection and transportation. In order to achieve this object, the present invention provides a booster of the type described above, in which a cover tube is attached to the rear wall of the booster shell to protrude from the rear surface of the booster piston and cover the valve tube housing the control valve. A connecting flange is integrally formed on the outer periphery of a screw member whose front end is screwed onto the tie rod by overlapping the flanges, and the rear wall of the booster shell and the mounting flange are sandwiched and connected between the front surface of the connecting flange and the tie rod. The present invention is further characterized in that the vehicle body, such as the front wall of the vehicle compartment, is sandwiched and connected between the rear surface of the connection flange and a nut screwed onto the screw member.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. S is a negative pressure booster, and the booster shell 1 is a pair of front and rear bowl-shaped bodies 1A, 1 made of synthetic resin, respectively.
It is constructed by butt-coupling B.

A cover tube 1C made of a steel plate is joined to the rear surface of the rear bowl-shaped body 1B, and its joining structure will be described later. The interior of the booster shell 1 includes a booster piston 2 housed therein so as to be able to reciprocate back and forth, and a rear surface. A first working chamber A at the front and a second working chamber B at the rear are defined by a piston diaphragm 3 whose inner peripheral part is fixed to the piston diaphragm 3 and whose outer peripheral part is clamped between the bowl-shaped bodies 1A and 1B. be done.

The first working chamber A is connected to the intake manifold of the internal combustion engine, which is a negative pressure source, through a negative pressure introduction pipe 4! The second working chamber B is controlled to be alternately communicated with an atmosphere inlet 6 opened at the rear end of the cover tube 1C. 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 reached by a raised rib 3a on the back surface of the piston diaphragm 3. is regulated by contacting the rear wall of the booster shell 1. The booster piston 2 is integrally formed with a valve cylinder 8 projecting in the axial direction from the rear surface of its central portion, and is slidably supported by a synthetic resin flat bearing 9 integrally molded into the rear bowl-shaped body 1B. At the same time, the rear end of the valve cylinder 8 is opened toward the atmosphere inlet 6 within the cover cylinder 1C.

The control valve 5 is configured in the valve chamber 8 as follows. That is, an annular first valve seat 101 is formed on the inner wall of the front part of the valve cylinder 8, and a valve piston 12 connected to the input rod 11 and forming the front end thereof is slidably connected to the front part of the valve cylinder 8. This valve piston 12
An annular second valve seat 102 surrounded by the first valve seat 101 is formed at the rear end. A base end portion 13a of a cylindrical valve body 13 with both ends open is clamped to the inner wall of the valve cylinder 8 via a valve body holding/holding cylinder 14 fitted into the valve cylinder 8.

This valve body 13 is molded from an elastic material such as rubber.
A thin-walled diaphragm 13b extends radially inward from the base end 13a, and a thick-walled valve portion 13c is connected to the inner peripheral end of the diaphragm 13b.
It is made to face the valve seats 101 and 102. Thus, the valve portion 13c can move back and forth by deforming the diaphragm 13b, and can also come into contact with the front end surface of the valve body holding cylinder 14. An annular reinforcing plate 15 is embedded in the valve part 13c, and the valve part 1 is inserted into the annular reinforcing plate 15.
3c is both valve seats 101 and 10.

The valve spring 16 is actuated to urge the valve toward the position. The outer part of the first valve seat 101 is connected to the first working chamber A through the through hole 17 of the booster piston 2, and to the first and second valve seats 101, 1.
The middle part of 02 is connected to the second working chamber B through another through hole 18,
Further, the inner side of the second valve seat 102 is always in communication with the atmosphere inlet 6 through the inside of the valve body 13.

The booster piston 2 is provided with a large-diameter hole 19 that opens at the center of its front surface and a small-diameter hole 20 that opens at the inner end of the large-diameter hole 19. An elastic piston 21 and an output piston 22 having the same diameter are sequentially slid together, and a reaction piston 23 having a smaller diameter than the elastic piston 21 is slid into the small diameter hole 20. The protruding small shaft 13a is pushed in and opposed to the rear end surface of the reaction piston 23.

The output piston 22 integrally has an output rod 22a that projects forward. The input rod 11 is always urged in the backward direction by the return spring 24, and its retraction limit is reached by a movable stopper plate 25, which is screwed onto the input rod 11, at an inward direction formed at the rear end of the cover tube 1C. It is regulated by coming into contact with the inside of the stopper flange 1Ca.

If the movable stopper plate 25 is rotated, the screwing position between the movable stopper plate 25 and the input rod 11 changes, so that the retraction limit of the input rod 11 can be adjusted back and forth. After the adjustment, the movable stopper plate 25 is fixed by tightening a lock nut 26 which is also screwed onto the input rod 11. Movable stopper plate 25
A ventilation hole 27 is provided so as not to block the air inlet 6. Filters 32 and 33 are attached to the outer end opening of the valve cylinder 8 to purify the air introduced from the atmospheric air inlet 6 and to be deformable so as not to interfere with the operation of the input rod 11.

Both front and rear walls of booster shell 1, that is, both bowl-shaped bodies 1A and 1B
One or more tie rods 3 passing through the booster piston 2 and the piston diaphragm 3 are connected between the opposing walls of the
In order to seal the through hole 31 of the booster piston 2, which is connected to the booster piston 2 through the tie rod 4 and through which the tie rod 34 passes, so as not to interfere with the operation of the piston 2, a The rolling diaphragm 35 is stretched.

It is preferable that the rolling diaphragm 35 is integrally molded with the piston diaphragm 3 as shown in the figure, and its fixed end is fitted into an annular attachment groove 36 on the circumferential surface of the tie rod 34 to be fixed therein. To specifically explain the connection structure between the tie rod 34 and the booster shell 1, the tie rod 34
integrally includes a tightening bolt 37 that passes through the front wall of the booster shell 1, a nut 39 that is screwed onto the tip of the bolt and tightened, and a stopper ring that is fixed to the outer periphery of the tie rod 34 in the first working chamber A. 38 and the front wall of the booster shell 1;
A mounting flange 40 of a brake master cylinder M stacked on the front surface thereof is sandwiched and connected.

At this time, an annular seal member 41 is interposed between the tie rod 34 and the front wall of the booster shell 1. Further, the front end of a screw member 43 that passes through the rear wall of the booster shell 1 and the mounting flange 1Cb at the front end of the cover tube 1C that overlaps the rear surface is screwed into the rear end of the tie rod 34. The rear wall of the booster shell 1 and the mounting flange 1Cb are clamped and connected by the front surface of the connecting flange 44 integrally provided on the outer periphery of the intermediate portion and the flange 45 provided protrudingly provided at the rear end of the tie rod 34. At this time, an annular seal member 47 is interposed between the screw member 43 and the rear wall of the booster shell 1. The above screw member 4
The rear half of the bolt 3 passes through the front wall W of the vehicle compartment, and the front wall W of the vehicle compartment is held between the nut 52 screwed and tightened to the rear end 51 and the rear surface of the connecting flange 44 .

Thus, the brake master cylinder M is connected to the vehicle body, that is, the front wall W of the vehicle interior via the tie rod 34.

The rear end of the cylinder body 58 of the brake master cylinder M penetrates the front wall of the booster shell 1 and protrudes into the first working chamber A, and the working piston 59 inside the cylinder body 58 penetrates the front wall of the booster shell 1 and projects into the first working chamber A.
The output rod 22a of the booster S is opposed to the rear end of the booster S. In the vehicle interior, a brake pedal 55 that is pivotally supported 54 on a fixed bracket 53 is connected to the rear end of the input rod 11 of the booster S via an adjustment connection fitting 56.

57 is a return spring that biases the brake pedal 55 rearward.

Next, to explain the operation of this embodiment, the illustrated state shows the non-operating state of the booster, and the valve piston 12, input rod 11 and brake pedal 55 which are connected to each other are connected to each other when the movable stopper plate 25 is fixed. The valve piston 12 is returned to the predetermined retracted position where it abuts the stopper flange 1Ca and is held by the spring force of the spring 24, and the valve piston 12 presses the front surface of the valve portion 13c via the second valve seat 102 to hold it in the valve body holding cylinder. 14
The first valve seat 101 is moved back until it comes into light contact with the front surface of the valve part 13c, thereby forming a small gap g between the first valve seat 101 and the valve part 13c.

Such a state can be easily obtained by adjusting the movable stopper plate 25 described above. As described above, the first working chamber A, which constantly stores negative pressure, communicates with the second working chamber B through the through hole 17, the gap g, and the through hole 18, and the front opening of the valve part 13c is connected to the second valve seat. 102, the negative pressure of the first working chamber A is transmitted to the second working chamber B, and both working chambers A,
The air pressure at B is in equilibrium.

Therefore, the booster piston 2 also occupies the illustrated retracted position by the elastic force of the return spring 7. Now, if the brake pedal 55 is depressed to brake the vehicle and the input rod 11 and the valve piston 12 are moved forward, the valve portion 13c, which is urged forward by the valve spring 16, will move forward following the valve piston 12. , since the gap g between the first valve seat 101 and the valve part 13c is extremely narrow as described above, the valve part 13c immediately closes to the first valve seat 1.
01 to cut off communication between the two working chambers A and B, and at the same time, the second valve seat 102 separates from the valve part 13c and opens the second working chamber B.
The air inlet 6 is communicated through the through hole 18 and the inside of the valve body 13 .

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 resist the return spring 7. The output rod 22 moves forward through the elastic piston 21.
Since the vehicle a is moved forward, the operating piston 59 of the brake master cylinder M is driven forward, and the vehicle is braked. When the operating piston 59 is driven, a forward thrust load is applied to the cylinder body 58 as described above, but this load is transmitted to and supported by the vehicle body, that is, the front wall W of the vehicle compartment via the tie rod 34. .

Therefore, the above-mentioned load does not act on the booster shell 1. On the other hand, when the small shaft 12a of the valve piston 12 comes into contact with the elastic piston 21 via the reaction piston 23 due to its advancement, the elastic piston 21 bulges and deforms toward the reaction piston 23 side due to the operational reaction force of the output rod 22a. A portion of the reaction force is fed back to the brake pedal 55 side via the valve piston 12, so that the driver can sense the output of the output rod 22a, that is, the braking force.

Next, when the depression force on the brake pedal 55 is released, the reaction force applied to the valve piston 12 and the return spring 24 are
The input rod 11 retreats due to the elastic force of , thereby seating the second valve seat 102 on the valve portion 13c and
c is brought into contact with the front surface of the valve body holding cylinder 14, so that the valve part 13
c receives the retreating force of the input rod 11 and undergoes compressive deformation in the axial direction.

As a result, a gap larger than the original gap g is deformed between the first valve seat 101 and the valve part 13c, so that the air pressures in both working chambers A and B are quickly balanced with each other through this gap, and their When the pressure difference disappears, the booster piston 2 moves backward due to the elastic force of the return spring 7, and the rib 3a of the piston diaphragm 3 comes into contact with the inner surface of the rear wall of the booster shell 1 and stops. Then, when the stopper plate 25 of the input rod 11 comes into contact with the stopper flange 1Ca, the valve part 13c
Since it is released from the retreating force of 1 and restored to its original shape, the gap with the first valve seat 101 can be narrowed to the small gap g again. As described above, according to the present invention, the first working chamber A is connected to the negative pressure source by the booster piston 2 housed inside the synthetic resin booster shell 1 so as to be able to freely reciprocate back and forth;
When the input rod 11, which is divided into the first working chamber A and the second working chamber B whose communication with the atmosphere is switched and controlled via the control valve 5, and which is connected to the booster piston 2 so as to be able to move back and forth, moves forward; so that a pressure difference is generated between the working chambers A and B to cause the booster piston 2 to follow the action,
The input rod 11 is connected to the control valve 5, and the front and rear walls of the booster shell 1 are connected via a tie rod 34 passing through the booster piston 2, and the tie rod 34 and the booster piston 2 are connected to each other. In a negative pressure booster provided with a sealing means 35 for permitting operation of the piston 2, a valve cylinder 8 protrudes from the rear surface of the booster piston 2 and houses the control valve 5 on the rear wall of the booster shell 1. A screw member 43 is formed by overlapping the mounting flange 1Cb of the cover tube 1C that covers the cover tube 1C and screwing the front end onto the tie rod 34.
A connecting flange 44 is integrally formed on the outer periphery of the connecting flange 44, and the rear wall of the booster shell 1 and the mounting flange 1Cb are sandwiched and connected between the front surface of the connecting flange 44 and the tie rod 34, and the rear wall of the connecting flange 44 and Since the vehicle body such as the front wall W of the vehicle compartment is sandwiched and connected between the nut 52 screwed onto the screw member 43, the rear wall of the booster shell 1, the cover tube 1C, and the tie rod 34 are connected to each other. The vehicle body and the tie rods 34 can be connected independently, and therefore the entire booster including the tie rods 34 and cover tube 1C can be assembled as a single completed unit before assembly to the vehicle body, and is independent of the vehicle body. It is easy to handle during inspection and transportation, and the booster can be easily and accurately assembled to the vehicle body.

Moreover, the clamping force between the connecting flange 44 of the screw member 43 and the nut 52, which should be applied to the vehicle body, and the clamping force between the connecting flange 44 and the tie rod 34, which should be applied to the rear wall of the synthetic resin booster shell 1, are independent of each other. Therefore, the tie rods 34 can be properly fastened to vehicle bodies and synthetic resin booster shells 1 having completely different rigidities and strengths according to their respective characteristics.
Furthermore, the tie rod 34 also serves as a connecting member between the booster shell 1 and the cover IC, so that the number of parts in the connecting portion between them is reduced and the structure can be simplified.

[Brief explanation of drawings]

The drawing is a longitudinal sectional side view of one embodiment of the device of the present invention. A: First working chamber, B: Second working chamber, S: Booster, W: Front wall of the vehicle compartment as the vehicle body. , 1 ...booster shell, 1C
......Cover tube, 1Cb...Mounting flange,
2...Booster piston, 5...Control valve, 6...Atmospheric inlet, 8...Valve cylinder, 11...Input rod , 34... Tie rod, 35... Rolling diaphragm as sealing means, 43... Screw member, 44...
...Connection flange, 52...Nut.

Claims (1)

[Claims] 1 The interior of the synthetic resin booster shell 1 is connected to a first working chamber A connected to a negative pressure source by a booster piston 2 accommodated therein so as to be able to reciprocate back and forth, and to the first working chamber A or the atmosphere via a control valve 5. When the input rod 11, which is divided into a second working chamber B whose communication is switched and controlled, and which is connected to the booster piston 2 so as to be able to move back and forth, moves forward, the pressure difference between the two working chambers causes the booster piston 2 to follow the movement. Room A,
The input rod 11 is connected to the control valve 5 so that the input rod 11 is located between In a negative pressure booster device in which a sealing means 35 is provided between the booster pistons 2 to allow the operation of the pistons 2, the control valve 5 is provided on the rear wall of the booster shell 1 and protrudes from the rear surface of the booster piston 2. The mounting flange 1Cb of the cover cylinder 1C that covers the accommodated valve cylinder 8 is overlapped, and a connecting flange 44 is integrally formed on the outer periphery of a screw member 43 whose front end is screwed onto the tie rod 34. The rear wall of the booster shell 1 and the mounting flange 1Cb are sandwiched and connected between the tie rod 34 and the rear wall of the booster shell 1, and the front part of the vehicle compartment is connected between the rear surface of the connecting flange 44 and the nut 52 screwed into the screw member 43. A negative pressure booster characterized in that a vehicle body such as a wall W is clamped and connected.