CN110962823A

CN110962823A - Diaphragm device for double-diaphragm vacuum booster

Info

Publication number: CN110962823A
Application number: CN201911365513.1A
Authority: CN
Inventors: 曹明明; 涂中萍; 李丕雷; 孙炳龙; 吴月
Original assignee: Jilin Dongguang Aowei Automobile Brake System Co Ltd
Current assignee: Jilin Dongguang Aowei Automobile Brake System Co Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-04-07

Abstract

The invention relates to a diaphragm device for a double-diaphragm vacuum booster, belonging to the technical field of automobile braking. The metal inserts are embedded in the edge of a diaphragm and are uniformly distributed along the circumference, and the number of the metal inserts is as follows: 8 ~ 14, metal insert's height H is greater than the distance L between the riveting back of back casing and the middle shell. The advantage is novel structure, under the prerequisite that does not increase the magnitude of interference of a diaphragm, also can improve the joint strength of a diaphragm, and metal insert puts into the diaphragm when the diaphragm shaping, and production technology is simple, and during the diaphragm atress, metal insert's height H is greater than the distance L between the riveting back of back casing and the middle casing. A diaphragm can not cross the space behind back casing and the riveting of well casing, and the diaphragm just can not deviate from, is the product of upgrading of a diaphragm of two diaphragm vacuum booster of conventionality, solves the defect that a diaphragm clamp force is low, easily takes off, has improved two diaphragm vacuum booster performances and reliability.

Description

Diaphragm device for double-diaphragm vacuum booster

Technical Field

The invention belongs to the technical field of automobile braking, and particularly relates to an improvement on an automobile vacuum booster component.

Background

The vacuum booster is a brake servo device in a light car brake system, a sedan car brake system and a mini car brake system, and is a key component in an automobile brake system. The working principle is that when a driver steps on a brake pedal, the vacuum generated by the working of a gasoline engine or the vacuum generated by a vacuum pump additionally arranged on a diesel engine is utilized, and the thrust generated by different pressure differences of two working cavities in a vacuum booster pushes a piston of a brake master cylinder to compress brake fluid in the brake master cylinder to generate hydraulic pressure, and the hydraulic pressure is transmitted to a wheel brake to enable a brake shoe to be in contact with a wheel hub so as to generate friction resistance to control the deceleration or braking of a vehicle. The diaphragm is an important part of the vacuum booster, and the main function of the diaphragm is to divide the booster into two working chambers.

The structure of a conventional vacuum booster is shown in fig. 1, and the double-cavity vacuum booster mainly comprises a diaphragm 1, a return spring 3, a valve body 4, two boosting discs 5, two diaphragms 6, a middle shell part 7, a front shell part 8, a rear shell part 9, a boosting disc 10, a feedback disc 11, a pressing block 12, a locking plate 13, a valve rod part 14, a dust cover part 15, a rubber valve part 16, an air valve seat 17, a main cylinder push rod part 18 and other parts. Wherein the front shell component 8 is in clearance fit with the rear shell component 9 and is riveted and fixed; the two diaphragms 6 are in clearance fit with the rear shell component 9, the two diaphragms 6 are extruded in the space between the middle shell component 7 and the front shell component 8 and the space between the middle shell component and the rear shell component 9, and the two power assisting discs 5 are in clearance fit with the valve body 4 and are fixedly riveted together. The rubber part of the middle housing part 7 is in a radial interference fit with the valve body 4. The outer diameter of a diaphragm 1 is in clearance fit with a rear shell component 9 and is extruded and fixed with the rear shell component 9 through a middle shell component 7, the inner diameter of the diaphragm 1 is in radial interference fit with a valve body 4, an inner hole of a power disc 10 is in clearance fit with the valve body 4 and is fixed through riveting, a pressing block 12 is in radial clearance fit with the valve body 4, one end of the pressing block is in contact with an air valve seat 17, and the other end of the pressing block is in contact with a feedback disc 11; the locking piece 13 is in clearance fit with the valve body 4, and the end surface is in contact with the rear shell component 9 and in clearance fit with the air valve seat 17. The air valve seat 17 is in clearance fit with the valve rod component 14, is fixed by riveting, the rubber valve component 16 is in interference fit with the valve body 4, is fixed by extruding the valve rod component 14 and the valve body 4, and the end surface is contacted with the air valve seat 17. The feedback disc 10 is in interference fit with the valve body 11 in the radial direction, and the main cylinder push rod part 18 is in clearance fit with the valve body 4. The master cylinder push rod member 18 is in end surface contact with the feedback disk 11.

The working principle is as follows: the double-cavity vacuum booster (see figure 2) is composed of two vacuum cavities (cavity A and cavity C) and two atmospheric cavities (cavity B and cavity D), and the vacuum source generated during the working of the engine pumps away the air in the A, B, C, D cavities through vacuum tubes to form a certain vacuum degree. When braking, the valve rod part of the booster is stressed to move forwards, the vacuum valve port of the booster is closed, two vacuum cavities (A cavity and C cavity are communicated all the time) and two atmospheric cavities (B cavity and D cavity are communicated all the time) are separated, then the atmospheric valve port is opened, air enters the two atmospheric cavities (B cavity and D cavity), the two diaphragms generate vacuum servo force under the action of the pressure difference of the front cavity and the rear cavity, and in addition, the valve rod input force enables the main cylinder push rod to generate increased output force.

And after the automobile engine is started, vacuumizing the vacuum cavity of the booster.

When the automobile brakes, the valve rod input force pushes the valve rod of the control valve component, the air valve seat, the rubber valve component and the like to move forwards, the rubber valve component is in contact with the sealing surface of the valve body and seals and closes the vacuum valve port, and an atmospheric chamber and a vacuum chamber of the booster are separated. Under the action of input force and vacuum force, the air valve seat overcomes the resistance of the valve rod return spring to continuously move forwards and is separated from the rubber valve component to open the atmospheric valve port, air begins to enter the atmospheric cavity of the vacuum booster so as to enable the atmospheric cavity and the vacuum cavity to generate pressure difference, the booster generates servo force, and the servo force is transmitted to the main cylinder push rod component through the diaphragm, the booster disc and the valve body acting on the feedback disc.

When the input force of the valve rod reaches a certain value, the pressure difference between the two cavities is rapidly increased due to the fact that the atmosphere entering the atmosphere cavity is continuously increased, the whole valve body, the diaphragm and the power-assisted disc move forwards under the action of the servo force, and the servo force acts on the feedback disc until the atmosphere valve port is gradually closed. An equilibrium state is reached.

When the brake is released, the valve rod input force is reduced. At the moment, under the action of the reaction force of the feedback disc and the resistance force of the return spring of the valve rod, the valve rod drives the air valve seat to return rapidly, the air valve seat compresses the rubber valve component to close the atmospheric valve port, the rubber valve component is separated from the sealing surface of the valve body to open the vacuum valve port, the atmospheric chamber of the booster is unblocked with the vacuum chamber, and the valve body moves backwards under the action of the reaction force of the push rod of the main cylinder and the resistance force of the return spring to return to the original working position.

The air inlet mode is as follows:

the air passages of the two atmospheric chambers (chamber B and chamber D) of the conventional dual diaphragm booster are on one diaphragm and two diaphragms, and the positions of the air passages are shown by arrows in FIG. 3. A diaphragm 1 has an outer diameter in clearance fit with the rear housing part 9 and an inner diameter in clearance fit with the middle housing part 7. The middle shell part 7 and the rear shell part 9 are fixedly connected in an interference fit mode in the axial direction. The strength of the connection between a membrane 1 and the central housing part 7 and the rear housing part 9 is proportional to the axial interference of a membrane. If the connection strength is ensured. The axial interference must be increased. This results in a less squeezed airway at one diaphragm E. If the size of the air passage at the position E is ensured, the interference magnitude of a diaphragm is reduced, and the connection strength is directly influenced. Leading to a failure of the diaphragm to fall off.

Disclosure of Invention

The invention provides a diaphragm device for a double-diaphragm vacuum booster, which aims to solve the problem that the conventional double-diaphragm booster with one diaphragm is easy to fall out of a shell to cause failure of the booster.

The technical scheme adopted by the invention is as follows: the metal inserts are embedded in the edge of a diaphragm and are uniformly distributed along the circumference, and the number of the metal inserts is as follows: 8-14.

The height H of the metal insert is larger than the distance L between the rear shell and the middle shell after riveting.

The diaphragm has the advantages that the structure is novel, the connection strength of the diaphragm can be improved on the premise of not increasing the interference magnitude of the diaphragm, the metal insert is placed in the diaphragm when the diaphragm is formed, the production process is simple, and when the diaphragm is stressed, the height H of the metal insert is larger than the distance L between the rear shell and the middle shell after riveting. A diaphragm can not cross the space behind back casing and the riveting of well casing, and the diaphragm just can not deviate from, is the product of upgrading of a diaphragm of two diaphragm vacuum booster of conventionality, solves the defect that a diaphragm clamp force is low, easily takes off, has improved two diaphragm vacuum booster performances and reliability.

Drawings

FIG. 1 is a schematic view of a conventional dual chamber vacuum booster;

FIG. 2 is a schematic diagram of the four chamber operating principles of a conventional dual chamber vacuum booster;

FIG. 3 is a schematic diagram of the air path position and air flow direction of a conventional dual diaphragm booster;

FIG. 4 is a schematic structural view of the present invention;

FIG. 5 is an enlarged view of a portion of the present invention;

FIG. 6 is a schematic view of the present invention in an installed state;

fig. 7 is a schematic view showing that the height H of the metal insert of the present invention is greater than the distance L between the rear housing and the middle housing after riveting.

Detailed Description

As shown in fig. 4 and 5, the metal inserts 2 are embedded in the edge of a diaphragm 1 and are uniformly distributed along the circumference, and the number of the metal inserts 18 is: 8-14;

as shown in fig. 7, the height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting.

As shown in fig. 6, the booster structure of the present invention is basically consistent with the working principle of the conventional dual-diaphragm vacuum booster, and can also improve the connection strength of a diaphragm 1 on the premise of not increasing the interference magnitude of the diaphragm 1, when the diaphragm is stressed, the height H of the metal insert 2 is greater than the distance L between the rear shell and the middle shell after riveting, and a diaphragm 1 cannot cross the space between the rear shell and the middle shell after riveting, and the diaphragm 1 cannot be separated.

Claims

1. A diaphragm device for a double-diaphragm vacuum booster is characterized in that: the metal inserts are embedded in the edge of a diaphragm and are uniformly distributed along the circumference, and the number of the metal inserts is as follows: 8-14.

2. A diaphragm assembly for a dual diaphragm vacuum booster as claimed in claim 1, wherein: the height H of the metal insert is larger than the distance L between the rear shell and the middle shell after riveting.