JPS5930776Y2 - air pressure booster - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air pressure booster used in a brake device or the like.

Some pneumatic boosters that perform a boosting action using negative pressure in the engine intake pipe or compressed gas from a compressor, etc. have a pressurized deformable member made of an elastic body.
The main body consisting of a pair of shells is divided into two chambers by a diaphragm and a power piston attached to the diaphragm, and thrust is applied to the power piston by operating the input shaft and creating a pressure difference between the two chambers. This thrust force is transmitted to the output shaft via the pressure member, while the reaction force from the output shaft is transmitted to the input shaft via the pressure member.

By the way, in conventional devices of this kind, the valve body that slidably holds the valve body connected to the input shaft is molded from phenol resin or the like, and integrated with the power piston, and the output shaft is attached to the integrally molded product. A recess is provided for accommodating the base end portion of the valve body and the pressurizing deformation member, a hole is provided in the integrally molded product in communication with the recess and has a smaller diameter than the recess, and the valve body head is inserted into the hole. Because they fit together in a slidable manner, when changing the diameter ratio of the recess and hole to change the input/output ratio, it is necessary to change the integrally molded product to match these dimensions and shape. It is necessary to prepare a molded product, which causes a large amount of cost.

Therefore, a method can be considered in which the power piston and the valve body are made up of separate members and the power piston is locked to the outer periphery of the valve body using, for example, a bayonet method, but in this case, the contact area between the valve body and the power piston is small. Therefore, there is a risk of damage due to differential pressure.

In addition, this type of configuration has the advantage that the power piston can be made of a steel plate, etc., but if a rod is provided that penetrates the piston and fixes the pair of shells, the strength around the through hole forming part of the piston will decrease. This may cause a decrease in the temperature.

In view of the above points, the present invention has a configuration in which the power piston is sandwiched between a valve body located on the rear chamber side of the main body consisting of a pair of shells and a plate located on the front chamber side. In order to facilitate changes in the size of the device, input/output ratio, etc., and to improve the strength of the connection between the power piston and the valve body, the plate is provided with a structure that surrounds the rod that passes through the power piston, By providing a flange portion that comes into contact with the front surface of the piston, it is possible to prevent the strength from decreasing around the rod penetration portion of the power piston.

The present invention will be described in detail below with reference to the illustrated embodiment.The main body 1 is composed of a front shell 1A and a rear shell 1B, and the inside of the main body 1 is defined by a diaphragm 2 into a front chamber 3 and a rear chamber 4. A plate-shaped power piston 5 attached to the front side of the diaphragm 2 has a valve body 6 located on the rear chamber 4 side and a plate 7 located on the front chamber 3 side.
is held between.

The valve body 6 is molded from phenolic resin, etc.
Inside this valve body 6, there is a valve seat part 8 and a cylinder part 9.
A valve body 11 connected to an input shaft 10 is slidably fitted into the cylinder portion 9 .

12 is a poppet valve that interlocks with the valve body 11, and the inside of the poppet valve 12 communicates with the atmosphere.

A hole 7A is formed in the plate 7 to slidably fit into the head 11A of the valve body 11, and a base end 13A of the output shaft 13 and a reinforcement made of an elastic material such as rubber are formed on the front surface of the plate 7. A holder 15 that slidably accommodates the pressure deformation member 14 is provided, and here, the holder 15, the plate 7, the power piston 5, and the valve body 6 have a screw that can be screwed into the front surface of the valve body 6. 16, and is removably fastened.

Communication holes (not shown) for communicating the front chamber 3 and the rear chamber 4 are formed in the holder 15, the plate 7, the blower piston 5, and the valve body 6, respectively. and the poppet valve 12 to communicate with the rear chamber 4.

An annular groove 11B serving as a recess is formed on the outer periphery of the valve body 11, and an engagement hole 5A that engages with the annular groove 11B is formed in the power piston 5.

Note that the annular groove 11B is formed between the power piston 5 and the valve body 11.
The valve body 11 is formed so as to be able to move slightly in the axial direction when the valve body 11 is engaged with the valve body 11.

The power piston 5 has a hole 5B formed therein for the rod 17 to pass through, and the rod 17 passes through the hole 5B.
Both ends are front and rear shell IA.

A flange portion 17 that penetrates through 1B and is provided on the rod 17
A and the nut 18 screwed onto the rod 17.
The rear shells IA and IB are fastened and fixed.

A flange portion 7B that surrounds the rod 17 and comes into contact with the front surface of the power piston 5 is formed on the outer periphery of the plate 7.

Here, one end portion of the bellows 19 that seals the front chamber 3 side surface of the rod 1T is connected to the flange portion 7 of the plate 7.
B and the front surface of the power piston 5.

Further, here, a flange portion 6A that surrounds the rod 17 and comes into contact with the rear surface of the power piston 5 is formed on the outer peripheral portion of the front end of the valve body 6, and the inner peripheral portion of the diaphragm 2 is formed on the outer peripheral portion of the front end of the valve body 6. The power piston 5 is held between the 7-run no. 6A and the rear surface of the power piston 5.

A return spring 20 presses the power piston 5 toward the rear chamber 4, and the rear end of the return spring 20 engages with a spring receiver IC formed on the front surface of the plate 7.

Since the bottom surface of the spring receiver IC is located in front of the head of the spring 16, there is no interference between the spring 20 and the screw 16, and the generation of abnormal noise is prevented. .

When the pneumatic booster having the above configuration is used in a brake system for an automobile, the front chamber 3 is connected to a negative pressure generating portion such as an engine intake pipe.

Now, when the input shaft 10 is pushed to the left against the spring force of a spring (not shown) by depressing the brake pedal, the valve body 11 and the poppet valve 12 pushed by another push spring (not shown) are pushed together. The poppet valve 12 is moved to the left with respect to the valve body 6, and the poppet valve 12 is seated on the valve seat 8 to open the front chamber 3.
communication with the rear chamber 4 is cut off.

After that, when the input shaft 10 is further pushed to the left, the valve body 1
1 is separated from the poppet valve 12, and the atmosphere is introduced into the rear chamber from inside the poppet valve 12 through between the valve body 11 and the poppet valve 12.

As a result, a pressure difference is generated between the front chamber 3 and the rear chamber 4, and a leftward thrust is generated in the power piston 5, thereby starting a boosting action.

This thrust force is transmitted from the plate 7 to the output shaft 13 via the pressurizing deformation member 14, and as a result, the output shaft 13 is pressed leftward and hydraulic pressure is generated in the mask cylinder (not shown).

At this time, the reaction force from the output shaft 13 is applied to the pressurized deformable member 14.
While the pressure is transmitted from the plate 7 to the power piston 5 through the pressure, the pressurized deformable member 14 is elastically deformed by the pressurization, and a part thereof protrudes into the hole TA of the plate 7, and the head 11A of the valve body 11. Abuts on the end.

As a result, a portion of the reaction force from the output shaft 13 is transmitted from the pressurizing deformation member 14 to the brake pedal via the valve body 11 and the input shaft 10.

Here, the ratio of the output from the output shaft 13 to the input from the input shaft 10 (input/output ratio) is the area where the pressure deformation member 14 contacts the plate 7 and the hole from which a part of the pressure deformation member 14 protrudes. 7A, in other words, the pressure deformation member 14
is determined by the ratio of the inner diameter of the holder 15 that accommodates the It is only necessary to change the dimensions and shapes of the plate γ and the valve body 11, and there is no need to change the power piston, valve body, etc., which have complicated shapes, so that cost reduction can be achieved.

Note that the reaction force transmitted from the pressure deformation member 14 to the plate 7 is further transmitted from the plate 7 to the valve body 6 via the power piston 5, but the plate 7, power piston 5, and valve body 6 have a so-called sand inch structure. and
Since a sufficiently large contact area is secured between these three parts 7, 5, and 6, stress concentration does not occur locally on the power piston 5.

Therefore, there is no risk of damage to the attachment portion between the three members 7, 5, and 6.

Next, as the diaphragm 2 moves to the left, the poppet valve 12 moves to the left while sitting on the valve seat 8 and seats on the valve body 11, and the internal mechanism of the booster becomes stationary. .

If the brake pedal is further depressed, the same effect as described above is repeated.

When you release the pressure on the brake pedal, diaphragm 2
The power piston 5 is returned to its original position as shown by the spring force of the return spring 20.

When the power piston 5 returns, if the return speed of the power piston 5 is greater than the return speed of the master cylinder, the output shaft 13 tries to pull out from the holder 15. Hole 15A is output shaft 1
Since the diameter is smaller than that of the base end 13A of the output shaft 1
3 will never come out from the holder 15.

In the pressure booster having the above configuration, the power piston 5
can be easily made by press forming a steel plate, etc., but there is a risk that the strength around the rod penetrating portion 5B will be reduced.

However, in the present invention, since the plate I is provided with the flange portion 7B that surrounds the rod 17 and comes into contact with the front surface of the power piston 5, the area around the wand penetration portion 5B of the power piston 5 is reinforced. There is no risk of destruction due to differential pressure.

Further, in this embodiment, since the bellows 19 is sandwiched between the flange portion 7B of the coupler plate 7 at one end and the front surface of the power piston 5, sufficient airtightness is ensured.

Furthermore, in this embodiment, the valve body 6 is provided with a flange portion 6A that surrounds the rod 17 and contacts the rear surface of the power piston 5, and the diaphragm 2 is connected to the flange portion 6A and the rear surface of the power piston 5. Since they are sandwiched between the front chamber 3 and the rear chamber 4, the airtightness between the front chamber 3 and the rear chamber 4 becomes higher.

As explained above, in this invention, the power piston is sandwiched between the valve body and the plate.
It becomes possible to easily change the input/output ratio by simply changing the plate, etc. without making any changes to the power piston, valve body, etc., and the input/output ratio can be changed at low cost.

Moreover, since the power piston is sandwiched between the valve body and the plate, when the reaction force from the output shaft is transmitted from the plate to the valve body via the power piston, it is localized to the power piston. There is no risk of stress concentration occurring, and there is no risk of damage.

Therefore, the power piston can be made thinner.

Moreover, in this invention, the plate is provided with a flange portion that surrounds the rod that passes through the power piston and contacts the front surface of the power piston. It can be reinforced and supported in the direction you want.

It becomes possible to prevent a decrease in strength due to thinning of the power piston.

[Brief explanation of the drawing]

The figure is a partially cutaway front view of an air pressure booster showing an embodiment of the present invention. 1... Main body, IA, IB... Shell, 2... Diaphragm, 3... Front chamber, 4... Rear chamber, 5... Power piston, 6... Valve poday, 6A...・Flange part, 7... Plate, 7B... Flange part, 10
...Input shaft, 11...Valve body, 13...Output shaft,
17...Rod, 19...Bellows.

Claims (4)

[Scope of utility model registration request] (1) A power piston attached to a diaphragm that defines a front chamber and a rear chamber in the main body consisting of a pair of shells,
a valve body located on the rear chamber side and provided with a valve body that generates a differential pressure between the front chamber and the rear chamber in conjunction with the input shaft; and a valve body located on the front chamber side and including the power piston. In the air pressure booster, the pair of shells are fixed by a rod that is sandwiched between the shells and a plate that transmits the differential pressure received to the output shaft, and that passes through the power piston. An air pressure booster further comprising a flange portion that comes into contact with the front surface of the power piston. (2) Utility Model Registration The air pressure booster according to claim 1, characterized in that the valve body is provided with a flange portion surrounding the rod. (3) Utility model registration Claim 1, characterized in that the bellows sealing the front chamber surface of the rod is held between the flange of the plate, which is one end of the bellows, and the front surface of the power piston. Air pressure booster. (4) Utility model registration Claims 1 or 2, wherein the valve body is provided with a flange portion that surrounds the rod and comes into contact with the rear surface of the power piston, and the diaphragm is connected to the valve body. An air pressure booster, characterized in that it is sandwiched between a flange portion of a body and a rear surface of the power piston.