KR20030010107A - Brake booster for car - Google Patents

Abstract

PURPOSE: A brake booster for a vehicle is provided to reduce noise generated by suction of air in case of operating a booster. CONSTITUTION: A brake booster for a vehicle is equipped with a casing, divided into a constant pressure chamber and a transformer chamber; a valve body(60), forming an air suction port(63); a plunger(70), installed to a cylinder formed inside the tip of the valve body; a poppet valve, fixed inside the air suction port; a fist elastic support member, elastically supporting the poppet valve; an input shaft(40), contacting with the rear end of the plunger; and a second elastic support member, elastically supporting the input shaft in the restoration direction. The first elastic support member(90) comprises a retainer(91), fixing the rear end of the poppet valve to the inner periphery, forming a spring seat portion(91a), and a cylindrical first coil spring(92), supported to the front end of the poppet valve and the spring seat portion. The second elastic support member(73) comprises a cylindrical second coil spring, supported to the wall of the cylinder(65) and the plunger(70). Air suction is performed more smoothly through the inner space of the first coil spring in case of operating the booster and therefore, the working noise of the booster is reduced.

Description

Brake booster for car}

The present invention relates to a brake booster for a vehicle, and more particularly, to a brake booster for a vehicle provided with a finger member for elastically supporting an input shaft and a poppet valve installed in the valve body.

In general, a brake booster (BRAKE BOOSTER) is a device that generates a large braking force with a small force by using a pressure difference between the vacuum and the atmosphere, the master cylinder assembly is coupled to the front shell, braking hydraulic pressure through the amplified force Is formed. 1 is a cross-sectional view showing a conventional vehicle brake booster having such a function.

As shown in FIG. 1, a conventional brake booster for a vehicle includes a casing 1 in which the front shell 1a and the rear shell 1b are hermetically coupled to each other, and the inside of the casing 1 includes a front seal 2a and 2b. Center plate 1c partitioned into rear chambers 2c and 2d, one end slidably penetrates the center of the center plate 1c, and the other end penetrates the rear shell 1b to protrude outward to control air inflow. It includes a valve body (6), an input shaft (4) interlocked by a brake pedal (not shown) and an output shaft (5) receiving a displacement force in accordance with its operation.

The front chambers 2a and 2b are divided into the front static pressure chamber 2a and the front transformer chamber 2b by the front diaphragm 3a and the front power piston 3b, and the rear chambers 2c and 2d are The rear diaphragm 3c and the rear power piston 3d are divided into the rear static pressure chamber 2c and the rear transformer chamber 2d.

The valve body 6 slides integrally with the diaphragms 3a and 3c and the power pistons 3b and 3d. For this purpose, the valve body 6 has a front diaphragm 3a and a front power piston at one end thereof. (3b) and the rear diaphragm 3c, the rear power piston 3d and the center plate 1c are directly coupled. In addition, the other end of the valve body 6 penetrates through the center portion of the rear shell 1b and communicates with the atmosphere, and an air suction part 6c is formed therein.

In the valve body 6, a pressure passage 6a communicating with the constant pressure chambers 2a and 2c and the transformer chambers 2b and 2d, and a transformer passage for communicating the atmosphere with the transformer chamber 2b and 2d ( 6b) is provided, and a plunger 7 which is engaged with the end of the input shaft 4 and slides in the axial direction is disposed. In addition, a reaction disk 5a is provided between the plunger 7 and the tip of the output shaft 5 to double the force applied due to the difference in the cross-sectional area and transmit it to the output shaft 5.

The valve body 6 is elastically supported and restored by the return spring 8 disposed in the front hydrostatic chamber 2a. That is, the return spring 8 is composed of a kind of coil spring, one end of which is supported inside the center of the front shell 1a forming the front positive pressure chamber 2a and the other end of which is supported on the center of one end of the valve body 6. .

On the other hand, reference numeral "6d" is an elastic poppet valve installed in the valve body 6 to control the inflow of air in accordance with the operation of the input shaft (4), the positive pressure passage (6a) by the poppet valve (6d) And the transformer passage 6b are selectively opened and closed.

In addition, a first spring 9a and a second spring 9b for elastically supporting the input shaft 4 and the poppet valve 6d are provided in the air intake 6c of the valve body 6, respectively. The first spring 9a is provided in a conical shape whose diameter gradually expands from one end to the other end, one end of which is supported on the outer circumference of the input shaft 4, and the other end of which the diameter is extended is fixed to the inner circumference of the air intake 6c. 4 is elastically supported toward the brake pedal (not shown). And the second spring (9b) is also provided in a conical shape, one end of which is supported on the outer periphery of the front end of the input shaft (5) and the other end of which the diameter is expanded is supported on the end of the poppet valve (6d), the poppet valve (6d) It is elastically supported in the direction opposite to the input shaft (4).

The operation of the conventional vehicle brake booster configured as described above is as follows.

First, when the driver does not step on the brake pedal (not shown), each of the positive pressure chambers 2a and 2c and the transformer chambers 2b and 2d is maintained in a vacuum in the negative pressure source (not shown). In this state, when the driver presses the brake pedal, the input shaft 4 moves forward and the plunger 7 is pushed toward the reaction disc 5a. In addition, the transformer passage 6b communicates with the outside air by the movement of the plunger 7, so that the outside air flows into the transformer chambers 2b and 2d through the air suction part 6c and the transformer passage 6b.

At this time, the external air is instantaneously introduced by the differential pressure, so that the diaphragms 3a, 3c, the power pistons 3b, 3d, and the valve body 6 are simultaneously pushed toward the positive pressure chambers 2a, 2c, The output amplified from the input is transmitted to the master cylinder assembly (not shown) through the reaction disk 5a and the output shaft 5 to generate braking hydraulic pressure. In addition, the return spring 8 arranged in the front positive pressure chamber 2a and the first spring 9a and the second spring 9b arranged in the air suction part 6c are compressed.

When the driver releases the brake pedal, the input / output shafts 4, 5, plunger 7 and the valve are caused by the elastic restoring force of the return spring 8, the first spring 9a and the second spring 9b. The main body 6 is restored.

However, in the conventional brake booster, the air intake is made inward from the outside of the conical first spring 9a and the second spring 9b as shown by the arrow of FIG. That is, since the first spring 9a and the second spring 9b are compressed as the input shaft 4 is advanced, the pitch between them is narrowed, which causes the intake air to flow into the first spring 9a. And since it does not pass smoothly between the pitch of the second spring (9b), there is a problem that the air intake noise is increased during the operation of the booster.

Moreover, when the input shaft 4 advances more than a predetermined section, the valve body 6 moves forward integrally with the plunger 7, and this time point is normally called booster KNEE POINT. Conventionally, after the booster KNEE POINT, the plunger 7 pushes the valve body 6 and outputs the key. The valve body 6 is provided with a key 6f and a key through the support jaw 6e. Therefore, the base jaw 6e acts as an air suction resistance during the booster operation.

The present invention is to solve this problem, it is an object of the present invention to provide a brake booster for a vehicle that can further reduce the operating noise by minimizing the interference during air intake by improving the spring structure for supporting the poppet valve and the input shaft.

1 is a cross-sectional view showing a conventional brake booster for a vehicle.

2 is a cross-sectional view schematically showing a brake booster for a vehicle according to the present invention.

3 and 4 are enlarged views taken from the "A" part of Figure 2, showing the initial state and the operating state of the booster.

* Description of the symbols for the main parts of the drawings *

10. Casing 40. Input shaft

50. Output shaft 60. Valve body

63. Air suction 64. Poppet valve

65. Cylinder 70. Plunger

73. Second Carton Member 90. First Carton Member

The present invention for achieving this object is;

A casing divided into a constant pressure chamber and a transformer chamber, a valve body formed at one side of the casing and having an air suction portion to communicate with the atmosphere, a plunger installed in a cylinder formed inside the front end of the valve body so as to move forward and backward, and a rear end of the plunger In combination with a poppet valve fixed in the air inlet to selectively communicate with and shut off the transformer chamber and outside air; In a brake booster for a vehicle having an input shaft installed so as to penetrate the air suction portion to contact the rear end of the plunger, and a second holding member elastically supported in the direction of restoring the input shaft.

The first holding member has a retainer provided with a spring seat portion while fixing the rear end of the poppet valve to the inner circumference of the air suction portion, and a cylindrical first coil spring having one end supported by the front end of the poppet valve and the other end supported by the spring seat portion.

The second holding member is characterized in that the one end is supported on the cylinder wall surface and the other end is formed of a cylindrical second coil spring supported by the plunger.

In addition, the step of the cylinder wall and the outer wall of the plunger are respectively provided to support both ends of the second coil spring.

According to this configuration, since air is sucked into the transformer chamber via the central portion of the cylindrical first coil spring during operation of the booster, the air suction is made more smooth and the suction noise is significantly lowered.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. Briefly, the accompanying drawings, Figure 2 shows the overall structure of the brake booster according to the present invention, Figures 3 and 4 is an extract showing the installation structure and the support member of the input shaft according to the present invention.

As shown in FIG. 2, the vehicle brake booster according to the present invention includes a casing 10 in which the front shell 11 and the rear shell 12 are hermetically coupled to each other, and the inside of the casing 10 includes a front seal 21 and a 22. ) And the center plate 13 divided into the rear chambers 23 and 24, and the center plate 13 penetrates so as to slide freely through the center of the center plate 13, and the front chambers 21, 22 and the rear chamber 23 Valve body 60 for controlling the inflow of air to the (24), the input shaft 40 for operating the valve body 60 by the operation of the brake pedal (not shown), and to receive the force doubled by the differential pressure The output shaft 50 provided with the reaction disk 51 of elastic material is provided in the front-end | tip.

The front chambers 21 and 22 are formed in the space between the front shell 11 and the center plate 13, which are again formed by the front diaphragm 31 and the front power piston 32. ) And front transformer chamber (22). In addition, the rear chambers 23 and 24 are formed in the space between the center plate 13 and the rear shell 12, which are also formed by the rear diaphragm 33 and the rear power piston 34. 23) and the rear transformer chamber (24). Unexplained reference numeral 14 is a vacuum connecting tube installed on the outer wall of the front shell 11 to communicate the front pressure chamber 21 and a negative pressure source (not shown), and the numeral 80 indicates a front pressure chamber 21. The return spring is arranged to elastically support the valve body 60.

The valve body 60 has a multi-step cylindrical shape, one end of which is the front diaphragm 31, the front power piston 32 and the center plate 13, the rear diaphragm 33 and the rear power piston ( 34) Fit in the center. And the other end of the valve body 60 is formed through the central portion of the rear shell 12, the air suction portion 63 is in communication with the outside is formed. At the open end of the air suction unit 63, a silencer 66 for reducing air intake noise and a filter 67 for preventing the inflow of foreign substances are disposed.

In the valve body 60, the positive pressure passage 61 for communicating the constant pressure chambers 21, 23 and the transformer chambers 22, 24, and the transformer passage for communicating the transformer chambers 22, 24 with the outside air. The cylinder 65 is processed in the axial direction at 62 and one center part. The cylinder 65 is provided with a plunger 70 which slides in the axial direction in association with the end of the input shaft 40, and the input shaft 40 is operated inside the valve body 60, that is, the inner wall of the air suction unit 63. By the poppet valve 64 of the elastic material which substantially controls the inflow of air is provided. The poppet valve 64 has a rear end fixed to the inner circumference of the air suction unit 63 and has a free end.

In addition, a first valve seat 60a is provided on the inner circumference of the valve body 60 to perform a vacuum valve function in combination with the poppet valve 64, so that the tip of the poppet valve 64 is seated on the first valve seat 60a. When the positive pressure passage 61 is closed. In addition, a second valve seat 71 is provided at the rear end of the plunger 70 so as to perform an air valve function in combination with the poppet valve 64, and the tip of the poppet valve 64 is seated on the second valve seat 71. When the outside air flows into each transformer chamber 22, 24 is blocked.

On the other hand, in the valve body 60, a poppet valve 64 and a first support member 90 and a second support member 73 for elastically supporting the poppet valve 64 and the input shaft 40 in opposite directions are provided. The sealing force of) is improved and the input shaft 40 is restored when the braking action is released. The structure thereof will be described with reference to FIGS. 3 and 4 as follows.

First, the first holding member (90) is a retainer (91) for fixing the poppet valve (64) on the inner wall of the air suction unit (63), and a first coil installed between the retainer (91) and the poppet valve (64). A spring 92 is provided. The retainer 91 has a cylindrical shape and is press-fitted to the air suction unit 63 to securely fix the rear end of the poppet valve 64. An end of the first coil spring 92 is seated inside the edge thereof. The spring seat part 91a is provided so that it may be. In addition, the first coil spring 92 is formed in a cylindrical shape having a predetermined inner diameter, one end of which is seated and supported by the spring seat portion 91a of the retainer 91, the other end of which is respectively the front end of the poppet valve 64. . Accordingly, the tip of the poppet valve 64 is normally maintained in close contact with the second valve seat 71.

And the second holding member 73 is made of a cylindrical second coil spring is installed to surround the outer wall of the plunger 70, for the installation of the inner end of the cylinder 65 and the outer wall of the rear end of the plunger 70 Steps 65a and 72 are formed, respectively. Accordingly, one end of the second holding member 72 is caught by the stepped portion 65a of the cylinder 65 and the other end thereof is held by the stepped portion 72 of the plunger 70, so that the input shaft 40 is elastically supported in the backward direction. Will be.

On the other hand, after the booster KNEE POINT in which the input shaft 40 advances the predetermined section or more, the gap between the respective pitches of the second holding member 73 is completely eliminated, thereby compressing the valve body together with the plunger 70. 60 goes forward. That is, after the booster KNEE POINT, the second support member 73 is completely compressed and the plunger 70 directly pushes the valve body 60 to output the output. Therefore, in the present invention, the supporting step structure for the key installation is not required, and thus the rear end of the plunger is made flat so that the air intake is more smoothly made.

Next, the operation and effects of the vehicle brake booster according to the present invention will be described.

First, when the driver presses the brake pedal and the input shaft 40 moves forward, the plunger 70 is pushed toward the reaction disk 51 so that the second valve seat 71 and the poppet valve 64 are spaced apart from each other so that the positive pressure chamber 21 23 and the transformer chamber 22, 24 communication is cut off.

Accordingly, the outside air flows into the transformer chambers 22 and 24 in the vacuum state through the transformer passage 62 by the air pressure differential, and the front diaphragm 31, the front power piston 32, and the rear diamond which are operable. As the fram 33 and the rear power piston 34 are pushed together with the valve body 60 to the output shaft 50, the output is transmitted to the master cylinder assembly (not shown) through the reaction disk 51 and the output shaft 50. To generate a braking pressure.

During the braking operation, the return spring 80 and the second support member 73 are compressed to elastically support the output shaft 50, the valve body 60, and the input shaft 40. In addition, since the first coil spring 92 of the first finger member 90 supports the poppet valve 64 in the forward direction of the input shaft 40, the tip of the poppet valve 64 is connected to the first valve seat 60a. It is firmly seated.

In addition, the inflow of the outside air is made through the air intake portion 63 and the transformer passage 62 in which the filter 67 and the silencer 66 are installed. Most of the air is shown in FIG. By flowing smoothly (in the direction of the arrow) relatively linearly through the inner space of the first coil spring 92 of the finger member 90, the air intake noise is significantly reduced as compared with the prior art.

When the driver releases the brake pedal, as shown in FIG. 3, the plunger 70 and the input shaft 40 are restored by the elastic restoring force of the return spring 80 and the second gripping member 73 and the poppet valve 64. ) Is pushed by the second valve seat 71 to be separated from the first valve seat 60a and serves as an air valve to prevent the inflow of air. In addition, as the poppet valve 64 is separated from the first valve seat 60a, the positive pressure passage 61 communicates with each other, so that the air in the front transformer chamber 22 and the rear transformer chamber 24 is vacuumed. 21) and the rear static pressure chamber (23). Subsequently, this air escapes through the vacuum connection pipe 14 connected with the negative pressure source to the initial state of the brake booster.

As described in detail above, according to the brake booster for a vehicle according to the present invention, first and second support members for elastically supporting the poppet valve and the input shaft are installed in the valve body, and the first support member has a cylindrical first coil. It includes a spring, the second holding member is also made of a cylindrical second coil spring is installed to surround the outside of the plunger. Accordingly, when the booster is operated, air intake is made more smoothly through the inner space of the first coil spring, thereby reducing the overall operating noise of the booster.

Claims (2)

A casing divided into a constant pressure chamber and a transformer chamber, a valve body formed at one side of the casing and having an air suction unit to communicate with the atmosphere, a plunger installed in a cylinder formed inside the front end of the valve body so as to move forward and backward, and the plunger; A poppet valve fixed in the air suction unit to selectively communicate with and shut off the transformer chamber and the outside air in combination with a rear end of the first and an elastic support for the poppet valve to closely contact the free end of the poppet valve to the rear end of the plunger. A brake booster for a vehicle having a first carbon member, an input shaft provided so that a tip thereof penetrates through the air suction portion to contact a rear end of the plunger, and a second carbon member elastically supports in a direction of restoring the input shaft to operate the plunger. In The first holding member 90 has a retainer 91 provided with a spring seat portion 91a while fixing a rear end of the poppet valve 64 to an inner circumference of the air suction unit 63, and one end of the poppet valve 64. A first coil spring 92 having a cylindrical shape supported at a tip of the other end and supported at the other end of the spring sheet portion 91a, The second support member (73) is a brake booster for a vehicle, characterized in that the one end is supported on the wall of the cylinder (65) and the other end is a cylindrical second coil spring supported by the plunger (70). The method of claim 1, Brake booster for a vehicle, characterized in that the step (65a) (72) is provided on the wall surface of the cylinder (65) and the outer wall of the plunger (70) to support both ends of the second coil spring (73).