A diaphragm device for a double diaphragm vacuum booster

Abstract

The present invention relates to a diaphragm device for a double-diaphragm vacuum booster, belonging to the technical field of automobile brakes. A metal insert is embedded in the edge of a diaphragm and is evenly distributed along the circumference. The number of the metal inserts is 8 to 14, and the height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting. The advantage is that the structure is novel, and the connection strength of the diaphragm can be improved without increasing the interference amount of the diaphragm. The metal insert is placed in the diaphragm during the diaphragm molding, and the production process is simple. When the diaphragm is subjected to force, the height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting. The diaphragm will not cross the space after the rear shell and the middle shell are riveted, and the diaphragm will not fall out. It is an upgraded product of the diaphragm of the conventional double-diaphragm vacuum booster, which solves the defects of low clamping force and easy fall out of the diaphragm, and improves the performance and reliability of the double-diaphragm vacuum booster.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile braking, in particular to the improvement of automobile vacuum booster components. Background Art

[0002] The vacuum booster is a brake servo device in the brake system of light vehicles, cars and micro vehicles, and is a key component in the automobile braking system. Its working principle is to use the vacuum generated by the working gasoline engine, or the vacuum generated by the vacuum pump installed on the diesel engine. When the driver steps on the brake pedal, the thrust generated by the different pressure differences between the two working chambers in the vacuum booster pushes the piston of the brake master cylinder, compresses the brake fluid in the brake master cylinder to generate hydraulic pressure, and transmits it to the wheel brake to make the brake shoe contact with the wheel hub to generate friction resistance to control the vehicle deceleration or braking. The diaphragm is an important component in the vacuum booster. The main function of the diaphragm is to separate the booster into two working chambers.

[0003] The structure of a conventional vacuum booster, such as Figure 1 The dual-chamber vacuum booster is mainly composed of a diaphragm 1, a return spring 3, a valve body 4, two booster discs 5, two diaphragms 6, a middle housing component 7, a front housing component 8, a rear housing component 9, a booster disc 10, a feedback disc 11, a pressure block 12, a locking plate 13, a valve stem component 14, a dust cover component 15, a rubber valve component 16, an air valve seat 17, a master cylinder push rod component 18 and other components. The front housing component 8 and the rear housing component 9 are clearance-matched and riveted; the two diaphragms 6 and the rear housing component 9 are clearance-matched, and the two diaphragms 6 are squeezed in the space between the middle housing component 7 and the front housing component 8 and the rear housing component 9. The two booster discs 5 and the valve body 4 are clearance-matched and riveted together. The rubber part of the middle housing component 7 is radially interference-fitted with the valve body 4. The outer diameter of a diaphragm 1 is loosely matched with the rear housing component 9, and is fixed by squeezing the middle housing component 7 and the rear housing component 9. The inner diameter of a diaphragm 1 is loosely matched with the valve body 4 in the radial direction. The inner hole of a power-assisting disc 10 is loosely matched with the valve body 4 and fixed by riveting. The pressing block 12 is loosely matched with the valve body 4 in the radial direction, one end is in contact with the air valve seat 17, and the other end is in contact with the feedback disc 11. The locking plate 13 is loosely matched with the valve body 4, and the end face is in contact with the rear housing component 9, and is loosely matched with the air valve seat 17. The air valve seat 17 is loosely matched with the valve stem component 14 and fixed by riveting. The rubber valve component 16 is loosely matched with the valve body 4, and is squeezed and fixed by the valve stem component 14 and the valve body 4, and the end face is in contact with the air valve seat 17. The feedback disc 10 is loosely matched with the valve body 11 in the radial direction, and the master cylinder push rod component 18 is loosely matched with the valve body 4. The master cylinder push rod component 18 is in contact with the end face of the feedback disc 11.

[0004] Working principle: Double chamber vacuum booster (see Figure 2) is composed of two vacuum chambers (A and C) and two atmospheric chambers (B and D). The vacuum source generated when the engine is working draws out the air in the four chambers A, B, C, and D through the vacuum tube to form a certain degree of vacuum. When braking, the booster valve stem component is forced to move forward, closing the booster vacuum valve port, separating the two vacuum chambers (A and C are always connected) and the two atmospheric chambers (B and D are always connected). After that, the atmospheric valve port is opened, and air enters the two atmospheric chambers (B and D). The two diaphragms generate vacuum servo force under the action of the pressure difference between the front and rear chambers, and combined with the valve stem input force, the master cylinder push rod generates an increased output force.

[0005] When the car engine is started, the vacuum chamber of the booster begins to be evacuated.

[0006] When the car brakes, the input force of the valve stem pushes the valve stem, air valve seat and rubber valve components of the control valve component forward. The rubber valve component contacts the sealing surface of the valve body and seals and closes the vacuum valve port, separating the booster's atmospheric cavity from the vacuum cavity. Under the action of the input force and vacuum force, the air valve seat overcomes the resistance of the valve stem return spring and continues to move forward to separate from the rubber valve component to open the atmospheric valve port. Air begins to enter the booster's atmospheric cavity, causing a pressure difference between the atmospheric cavity and the vacuum cavity, causing the booster to generate a servo force. The servo force is transmitted to the master cylinder push rod component through the diaphragm, the booster disc, and the valve body to the feedback disc.

[0007] When the input force of the valve stem reaches a certain value, the air entering the atmospheric cavity increases continuously, thereby rapidly increasing the pressure difference between the two cavities, and the entire valve body, diaphragm and power-assisting disc move forward under the action of the servo force, and the servo force acts on the feedback disc until the atmospheric valve port is gradually closed and reaches a balanced state.

[0008] When the brake is released, the input force of the valve stem decreases. At this time, under the reaction force of the feedback plate and the resistance of the valve stem return spring, the valve stem drives the air valve seat to return quickly, and the air valve seat compresses the rubber valve component to close the atmospheric valve port. The rubber valve component separates from the valve body sealing surface to open the vacuum valve port, and the booster's atmospheric cavity and vacuum cavity are unblocked. Under the reaction force of the master cylinder push rod and the resistance of the return spring, the valve body moves backward and returns to the original working position.

[0009] Air intake method:

[0010] The air passages of the two atmospheric chambers (chamber B and chamber D) of the conventional double diaphragm booster are on the first and second diaphragms. Figure 3At the arrow shown. The outer diameter of a diaphragm 1 has a clearance fit with the rear shell component 9, and the inner diameter has a clearance fit with the middle shell component 7. The axial connection is fixed by the interference fit between the middle shell component 7 and the rear shell component 9. The connection strength between a diaphragm 1 and the middle shell component 7 and the rear shell component 9 is proportional to the axial interference of the diaphragm. If the connection strength is guaranteed, the axial interference must be increased. This will cause the airway at E of the diaphragm to be squeezed and reduced. If the size of the airway at E is guaranteed, the interference of the diaphragm will be reduced, which will directly affect the connection strength. This will cause a diaphragm to fall off. Summary of the invention

[0011] The present invention provides a diaphragm device for a double-diaphragm vacuum booster to solve the problem that a diaphragm of a conventional double-diaphragm booster is easily separated from a housing, resulting in booster failure.

[0012] The technical solution adopted by the present invention is that metal inserts are embedded in the edge of a diaphragm and are evenly distributed along the circumference. The number of the metal inserts is 8 to 14.

[0013] The height H of the metal insert of the present invention is greater than the distance L between the rear shell and the middle shell after riveting.

[0014] The advantages of the present invention are novel structure, and the connection strength of a diaphragm can be improved without increasing the interference of a diaphragm. The metal insert is placed in the diaphragm when the diaphragm is formed, and the production process is simple. When the diaphragm is subjected to force, the height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting. A diaphragm will not cross the space after the rear shell and the middle shell are riveted, and the diaphragm will not fall out. It is an upgraded product of a diaphragm of a conventional double-diaphragm vacuum booster, which solves the defects of low clamping force and easy fall out of a diaphragm, and improves the performance and reliability of the double-diaphragm vacuum booster. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of a conventional double-chamber vacuum booster;

[0016] Figure 2 It is a schematic diagram of the working principle of the four chambers of a conventional double-chamber vacuum booster;

[0017] Figure 3 This is a schematic diagram of the airway position and air flow of a conventional double-diaphragm booster;

[0018] Figure 4 It is a schematic diagram of the structure of the present invention;

[0019] Figure 5 It is a partial enlarged view of the present invention;

[0020] Figure 6 It is a schematic diagram of the installation state of the present invention;

[0021] Figure 7 It is a schematic diagram showing that the height H of the metal insert of the present invention is greater than the distance L between the rear shell and the middle shell after riveting. DETAILED DESCRIPTION

[0022] like Figure 4 , 5 As shown, the metal insert 2 is embedded in the edge of a diaphragm 1 and is evenly distributed along the circumference. The number of the metal inserts 18 is 8 to 14.

[0023] like Figure 7 As shown, the height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting.

[0024] like Figure 6 As shown, the booster structure of the present invention is basically consistent with the working principle of a conventional double-diaphragm vacuum booster. Without increasing the interference fit of a diaphragm 1, the connection strength of a diaphragm 1 can also be improved. When the diaphragm is subjected to force, the height H of the metal insert 2 is greater than the distance L between the rear shell and the middle shell after riveting. The diaphragm 1 will not cross the space after the rear shell and the middle shell are riveted, and the diaphragm 1 will not fall out.

Claims

1. A diaphragm device for a double-diaphragm vacuum booster, wherein the double-diaphragm vacuum booster structure is that the front housing part and the rear housing part are clearance-matched and riveted and fixed; two diaphragms are clearance-matched with the rear housing part, the two diaphragms are squeezed in the space between the middle housing part and the front housing part and the rear housing part, two booster discs are clearance-matched with the valve body and riveted and fixed together, and the rubber part of the middle housing part is radially interference-fitted with the valve body; the outer diameter of one diaphragm is clearance-matched with the rear housing part, and is squeezed and fixed by the middle housing part and the rear housing part, the inner diameter of one diaphragm is radially interference-fitted with the valve body, and one booster disc is clearance-matched with the rear housing part, and is squeezed and fixed by the middle housing part and the rear housing part, and the inner diameter of one diaphragm is radially interference-fitted with the valve body, and one booster disc is clearance-matched with ... clearance-matched with the rear housing part, and the inner diameter of one diaphragm is radially interference-fitted with the valve body, and one booster disc is clearance-matched with the rear housing part, and the inner diameter of one diaphragm is clearance-matched The inner hole of the force plate has a clearance fit with the valve body and is fixed by riveting. The pressure block has a clearance fit with the valve body in the radial direction, one end of the pressure block contacts the air valve seat and the other end of the pressure block contacts the feedback plate. The locking plate has a clearance fit with the valve body, the end face contacts the rear housing component and has a clearance fit with the air valve seat. The air valve seat has a clearance fit with the valve stem component and is fixed by riveting. The rubber valve component has an interference fit with the valve body and is fixed by extrusion between the valve stem component and the valve body, and the end face contacts the air valve seat. The feedback plate has an interference fit with the valve body in the radial direction, the master cylinder push rod component has a clearance fit with the valve body, and the master cylinder push rod component contacts the end face of the feedback plate. The characteristics are as follows: The metal inserts are embedded in the edge of a diaphragm and are evenly distributed along the circumference. The number of the metal inserts is 8 to 14.

2. A diaphragm device for a double diaphragm vacuum booster according to claim 1, characterized in that: The height H of the metal insert is greater than the distance L between the rear shell and the middle shell after riveting.

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