JPS6010231Y2 - Output structure of tandem vacuum booster - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a vacuum booster, particularly an output section structure of a tandem vacuum booster.

The interior of the shell is divided into two chambers, front and rear, by partition walls, and
A vacuum booster is a tandem booster in which each chamber is further divided into two pressure chambers by a power piston integrated with a diaphragm, and each power piston is driven by vacuum pressure to transmit its force to the output shaft. It is conventionally known as a type vacuum booster.

Further, in the above device, a reaction force transmission mechanism is provided for transmitting a reaction force proportional to the brake fluid pressure to the driver,
The reaction force applied to the output shaft is absorbed by a disk-shaped deformable body such as rubber.
A so-called reaction disk is used to reduce the pressure and transmit it to the input shaft.

That part is configured as shown in FIG. 1, for example.

The output shaft 1 is engaged with a cup-shaped boss 2 of the front piston, and the input shaft 3 is inserted into the rear piston boss 4.

A reaction disk 5 is inserted into the latter boss portion 4, and a protrusion 6 provided on the front piston boss portion 2 is attached to one side of the reaction disk 5.
The input shaft 3 is in pressure contact with the other surface during braking.

The above structure has the advantage that during operation, the force of the front piston does not act on the reaction disk 5, and only the force of the rear piston acts on it, so that the load on the reaction disk 5 is reduced.

By the way, in order to reduce the weight of the device, when the shell and piston are made of soft and lightweight materials such as plastic or aluminum, the boss portion 2 of the front piston shown in FIG. A large load is applied to the parts, and if the parts are made of the above-mentioned materials, this can cause weakening or destruction of the parts.

In addition, due to the compressive deformation force of the reaction disk 5,
The boss portion 4 of the rear piston has a similar cause.

Therefore, the object of this invention is to improve the piston boss section and provide an output section structure that eliminates the above-mentioned dangers.

In order to achieve the above object, this invention forms a cylindrical part at the center of the boss part of the front piston, engages one end of the cylindrical part with a part of the output shaft, and attaches it to the output shaft. The output piston is inserted into the cylindrical portion, and the distal end surface of the output piston is brought into contact with a reaction disk inserted into the boss portion of the rear piston.

Hereinafter, an embodiment of this invention will be described based on FIG. 2.

The output structure according to this invention is provided with a cylinder part 12 protruding forward at the center of the boss part 11 of the front piston 10, and the inside of the cylinder part 12 is made of metal or other material with sufficient rigidity. An output piston 13 is inserted, an output shaft 14 is inserted into the output piston 13, and a receiving collar 15 integrated with the output shaft 14 is pressed against the cylindrical portion 12 by a return spring 16.

A reaction disk 17 having the same diameter as the output piston 13 is in contact with the rear end of the output piston 13.

The reaction disk 17 engages with a stepped portion inside a guide bush 20 that is inserted into the boss portion 19 of the rear piston 18 in an airtight manner.

The guide bushing 20 is also made of a sufficiently rigid material.

An input shaft 21 is inserted into this guide bush 20, and this input shaft 21 is inserted into the reaction disk 17 during operation.
press against.

The tandem type vacuum booster shown in the drawings penetrates the reinforcing member 23 in the axial direction of the shell 22, and connects the mounting arm 25 of the mask cylinder 24 to one end of the reinforcing member 23, and connects the mounting plate 26 of the vehicle body to the other end. However, by supporting the reaction force of the mask cylinder 24 with the vehicle body via the reinforcing member 23, the shell 2
This structure reduces the burden placed on the shell 22, and allows the shell 22 to be made of a soft and light material such as plastic or aluminum.

The above device maintains each chamber in a vacuum state under normal conditions, opens the poppet valve mechanism by operating the input piston 27, and communicates the chambers behind each power piston 10, 18 with the atmosphere, thereby boosting power. At the same time, the reaction force due to the braking fluid pressure generated in the mask cylinder 24 is transferred to the reaction disk 1 through the output shaft 14.
7, the pressure is proportionally reduced, and the pressure is transmitted to the input shaft 21 and input piston 27.

Since the output part structure of the vacuum booster of this invention is constructed as described above, the boss part 11 of the front piston 10 has a cylindrical part 12 that is a part of the output shaft 14. engages with the output shaft 14 through the
4, but the boss portion 11 is connected to the reaction disk 1.
The output piston 13 is inserted into the cylindrical portion 12 without contacting the piston 7.
Since the structure is such that the output piston 13 is made of a material with sufficient rigidity, the boss portion 11
Even if the piston 10 including the piston 10 is constructed of a soft lightweight material, there is no risk of weakening or breaking.

Further, if a separate guide bushing 20 is inserted into the boss portion 19 of the rear piston 18 as in the embodiment and the reaction disc 17 is housed in the guide bushing 20, the reaction disc 17 may be deformed. The risk of weakening or breaking the boss 19 due to pressure is eliminated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a part of the output structure of a conventional vacuum booster, and FIG. 2 is a sectional view of a vacuum booster equipped with the output structure according to this invention. 10...Front piston, 11...Boss part, 12...Cylinder part, 13...Output piston, 14...Output shaft , 15... Uketsuba, 16... Return spring, 17... Reaction disc, 18... Rear piston, 19
...Boss part, 20 ... Guide bush, 21 ... Input shaft.

Claims (1)

[Scope of utility model registration request] The interior of the shell is divided into two chambers, front and rear, by a partition wall, with a front piston provided in the front chamber and a rear piston provided in the rear chamber.
In the output part structure of a tandem vacuum booster in which each piston is driven by vacuum pressure and the output shaft engaged with the front piston moves forward and backward, a cylindrical part is formed at the center of the boss part of the front piston. At the same time, one end of the cylindrical part is engaged with a part of the output shaft, the output piston attached to the output shaft is inserted into the cylindrical part, and the tip surface of the output piston is inserted into the boss part of the rear piston. An output section structure of a tandem vacuum booster characterized by contacting a disk.