JPH0437017Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tandem pneumatic booster used in brake systems of automobiles and the like.

(Prior Art) Conventionally, a tandem type pneumatic booster has been configured as shown in FIG. 5 as an example. In the figure, 1 is the front shell, 2 is the rear shell,
Both shells form an integral housing. The inside of the housing is divided into front and rear chambers by a center plate 3, and the front chamber is further divided into a front constant pressure chamber 6 and a front variable pressure chamber 7 by a diaphragm 5 holding a front power piston 4, and the rear chamber is a front chamber containing a rear power piston. The rear constant pressure chamber 10 and the rear variable pressure chamber 11 are each partitioned by a diaphragm 9 holding a diaphragm 8. A cup-shaped center body 12 is fixed to the front power piston 4, and a valve body 13 is fixed to the rear power piston 8. Both bodies 12 are movably inserted,
13 are connected. Note that the center body 12 has a hole 1 in which the claw piece 13a of the valve body 13 engages.
2a is provided, and both the constant pressure chambers 6 and 10 are communicated through the hole 12a. Further, a bellows 15 is bridged between the center plate 3 and the diaphragm 9 including the rear power piston 8, and the bellows 15 is connected to both the variable pressure chambers 7, 1.
1 is connected. Further, negative pressure of the engine is introduced into the front constant pressure chamber 6 through an air supply pipe 16.

A large diameter proximal portion 18a of an output shaft 18 whose distal end is engaged with the master cylinder 17 is fitted into the bottom of the center body 12, while the valve body 1
A rubber reaction disk 19 and a spacer 20 are housed at the bottom of the large diameter hole 14 of No. 3. Further, the valve body 13 is provided with a small diameter hole 21 connected to the large diameter hole 14, and
A negative pressure passage 22 is provided with one end opening into the rear constant pressure chamber 10 and the other end opening into the rear hollow portion 13b of the valve body 13. A plunger 23 is slidably fitted into the small-diameter hole 21, and one end of an input shaft 24 that is connected to a brake pedal (not shown) is connected to its rear end. This plunger 2
Valve seats 23a and 22a are formed at the rear end of 3 and the opening of the negative pressure passage 22 on the side of the hollow part 13b.
A poppet valve 25, which can be seated and taken off, is installed inside a and 22a. The valve body 13 also includes a ventilation passage 2 that communicates the rear pressure change chamber 11 and the hollow portion 13b.
6 is provided, and the poppet valve 25 is connected to the valve seat 23.
a, 22a, the ventilation path 2
6 and the negative pressure passage 22 are both closed. The poppet valve 25 is normally biased in the seating direction by a spring 27. Further, a return spring 28 is interposed in the front constant pressure chamber 6 to return the front power piston 4 to its original state.

With such a configuration, when the brake pedal is depressed to move the input shaft 24 forward, the plunger 23 moves forward, its valve seat 23a separates from the poppet valve 25, and the atmosphere flows through the air passage 26 into the rear transformation chamber 1.
1 and further into the front transformation chamber 7 through the bellows 19. This introduction of atmospheric air creates a pressure difference between the front constant pressure chamber 6 and rear constant pressure chamber 10, which are at negative pressure, and the rear front variable pressure chamber 7 and rear variable pressure chamber 11, and the front power piston 4 and rear power piston 8 A forward thrust is generated. This thrust is transmitted to the output shaft 18 via the center body 12 and acts as a booster. Thereafter, when the brake pedal is further depressed, the reaction disk 19 is elastically deformed by the reaction force, and a portion thereof protrudes into the small diameter hole 21, causing the plunger 23 to retreat. This plunger 23 is moved back and a reaction force is transmitted to the input shaft 24, and a boosting action is performed in response to the input. When the brake pedal is no longer depressed, the plunger 23 is moved back and its valve seat 23a is pushed back into the poppet. valve 25
The valve seat 22a of the negative pressure passage 22 is further opened. As a result, the introduction of atmospheric air into the rear variable pressure chamber 11 is cut off, and the negative pressure in the rear constant pressure chamber 10 is transferred to the rear variable pressure chamber through the negative pressure passage 22 and the ventilation passage 26.
1 and into the front pressure variable chamber 7, the differential pressure becomes smaller, the thrust is reduced, and the whole returns to its original state by the pressing force of the return spring 28.

(Problem to be solved by the invention) By the way, in the tandem type pneumatic booster described above, it is necessary to prevent the output shaft 18 from coming off from the center body 12 and to adjust the height of the output shaft 18. Therefore, as shown in FIG. 5, a retainer 29 that holds the large diameter portion 18a of the output shaft 18 is press-fitted into the inner bottom of the center body 12, and an adjusting member 30 having a threaded portion 30a is separately prepared. It was designed to be screwed into the tip of the output shaft 18. That is, the retainer 29 and the adjustment member 30
The problem is that the number of parts required increases, leading to an unavoidable increase in costs. Further, the output shaft 18 must be machined with a knurl 18b or the like as a gripping portion when the adjusting member 30 is screwed in, and an increase in costs is unavoidable in this respect as well.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to provide a tandem type pneumatic booster with a simple structure and a reduced number of parts.

(Means for Solving the Problems) In order to achieve the above object of the present invention, a hole is provided at the bottom of the center body that is inserted into the large diameter hole of the valve body, and a screw is installed at the base end of the output shaft. and the output shaft is configured to engage with the hole via a threaded portion.

(Function) In the tandem type pneumatic booster having the above configuration, the output shaft is engaged with the hole in the center body through the threaded part, so that the threaded part does not prevent the output shaft from coming off from the center body. Of course, it can also have the function of adjusting the height of the output shaft.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings. In the following figures, the same parts as those shown in FIG.

1 and 2 show a first embodiment of the present invention. In this first embodiment,
Center body 1 assembled to valve body 13
2 is formed by sheet metal processing, and has a protrusion 31 with an irregular cross section (hexagonal in this case) on the cup-shaped bottom that is fitted into the large diameter hole 14 of the valve body 13. A cylindrical portion 32 integrally formed by burring is provided at the center of the protruding portion 31, and a female thread 33 is carved on the inner surface of the cylindrical portion 32. On the other hand, the output shaft 18 is entirely formed into a rod shape, and a male thread 34 is formed at the base end thereof. The output shaft 18 is connected to the center body 12 by screwing its male thread 34 into the female thread 33 of the cylindrical portion 32.

To assemble the output shaft 18 to the center body 12, first insert a jig (not shown) into the space in the protrusion 31 to prevent the center body 12 from rotating. Just screw it into section 32. In this case, it is desirable to provide a hexagonal portion 35 at the tip of the output shaft 18 and engage a suitable turning screw (not shown) with the hexagonal portion 35 to rotate the output shaft 18.

With this configuration, the output shaft 18 is prevented from coming off from the center body 12 by screwing its male thread 34 into the female thread 33 of the center body 12, and the height can be increased by changing the screwing amount. It can be adjusted arbitrarily, and the retainer 29 and adjustment member 30, which were conventionally necessary, can be made unnecessary. Furthermore, in the first embodiment, since the center body 12 is made of sheet metal, it can be welded and fixed to the front power piston 4, making the assembled structure even stronger.

FIG. 3 shows a second embodiment of the present invention. The features of this second embodiment are as follows:
Instead of providing the female thread 33 in the cylindrical portion 32, a holder 36 having a female thread 33a is fixed to the cylindrical portion 32 by caulking, and the output shaft 18 is indirectly connected to the center body 12 through the holder 36. At the connected points. In this case, the presence of the holder 36 increases the strength of the threaded portion, making it possible to connect the output shaft 18 to the center body 12 in a more stable state.

FIG. 4 shows a third embodiment of the present invention. The features of this third embodiment are as follows:
A cylindrical portion 32 is attached to the protruding portion 31 of the center body 12.
Instead of providing a central hole 32a at the bottom of the protruding portion 31, a female thread 33b is provided in the existing spacer 20 housed in the large diameter hole 14 of the valve body 13, and a female thread 33b is provided in the output shaft 18. This is because a large diameter stopper 37 is provided. In this case, since the output shaft 18 can be screwed using the existing spacer 20, it is sufficient to simply provide the center hole 32a in the center body 12, which makes manufacturing easier. Here, the stopper 37 acts to prevent the center body 12 from coming off, but this can be replaced by a step provided on the output shaft 18.

In the above embodiments, the center body 12 is made of sheet metal, but it may be made of resin instead. In this case, the cylindrical portion 32 is also formed by integral molding.

Further, in the overall structure, the configuration for communicating the two constant pressure chambers 6 and 10 and the two variable pressure chambers 7 and 11 is not limited to the above embodiment, and may be replaced with other aspects.

(Effects of the invention) As explained above in detail, the tandem pneumatic booster according to the invention has a hole at the bottom of the center body that is inserted into the large diameter hole of the valve body. Since the base end of the output shaft is engaged with the base end of the output shaft through the threaded part, the output shaft can be assembled without requiring any special members to prevent it from coming off or to adjust the height, simplifying the structure. This has the effect of achieving increased efficiency and cost reduction.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of a tandem type pneumatic booster according to the present invention, and FIG.
3 is a cross-sectional view of main parts showing the second embodiment of the present invention; FIG. 4 is a cross-sectional view of main parts showing the third embodiment of the present invention; FIG. The figure is a sectional view showing a conventional tandem type pneumatic booster. 1...Front shell, 2...Rear shell, 3
... Center plate, 4, 8 ... Power piston, 5, 9 ... Diaphragm, 6, 10 ... Constant pressure chamber, 7, 11 ... Variable pressure chamber, 12 ... Center body, 13 ... Valve body, 14 ... Large diameter hole, 1
5... Bellows, 18... Output shaft, 19... Reaction disk, 20... Spacer, 23...
... Plunger, 24 ... Input shaft, 25 ... Poppet valve, 32 ... Cylindrical part (hole), 32a ... Center hole,
33, 33a, 33b...Female thread (threaded part), 3
4...Male thread, 36...Holder.

Claims (1)

[Scope of utility model registration request] The inside of the housing, which consists of a front shell and a rear shell, is divided into front and rear chambers by a center plate, and the front and rear chambers are divided into a front constant pressure chamber, a front variable pressure chamber, and a rear chamber by diaphragms that hold the front power piston and rear power piston, respectively. It is divided into a constant pressure room and a rear variable pressure room, and
The two constant pressure chambers and the two variable pressure chambers are communicated with each other, and the bottom of a cup-shaped center body fixed to the front power piston is slidably fitted into a large diameter hole of a valve body fixed to the rear power piston. By operating the valve mechanism built into the valve body in accordance with the movement of the input shaft, atmospheric air is introduced into each of the variable pressure chambers to generate thrust in each of the power pistons, and this thrust is transferred to the output shaft via the center body. In a tandem pneumatic booster, the reaction force at that time is transmitted to the input shaft via a reaction disk housed in the bottom of a large diameter hole of the valve body,
A tandem pneumatic doubler, characterized in that a hole is provided at the bottom of the center body, a screw is provided at the base end of the output shaft, and the output shaft is engaged with the hole through a threaded portion. power device.