KR100888375B1 - Brake booster - Google Patents

Abstract

A brake booster is provided to improve the output since the pressurizing piston is suppressed in plunger. A brake booster comprises a cell in which the constant pressure chamber and transformation chamber are formed, a valve apparatus(20) which pressurizes the output axis(18) while moving with the pressure difference of the transformation chamber and constant pressure chamber. A pressurizing piston(40) combined in the leading end of plunger(22) is installed in the valve apparatus in order to pressurize a reaction disk(25).

Description

Brake booster {BRAKE BOOSTER}

The present invention relates to a brake power booster, and more particularly, to a brake power booster capable of rapidly raising the output when emergency braking is performed.

Conventional brake booster is a device that can exhibit a large braking force even with a small force by using the pressure difference between the intake pressure and the atmospheric pressure of the vehicle engine. In other words, when the driver presses the brake pedal, the device generates much more power than the force applied to the pedal.

1 is a cross-sectional view showing a conventional brake booster. As shown, the power supply apparatus includes a cell 1 having a positive pressure chamber 2 and a transformer chamber 3 partitioned therein. In addition, the positive pressure chamber 2 and the transformer chamber 3 communicate with each other according to the operation of the input shaft 4 so that the pressures in the positive pressure chamber 2 and the transformer chamber 3 are equal to each other, or the positive pressure chamber 2 and the transformer chamber ( The valve device 5 is provided so that communication of 3) is interrupted and the transformer chamber 3 is in communication with the atmosphere so that a pressure difference is generated between the constant pressure chamber 2 and the transformer chamber 3. The suction pressure of the vehicle engine acts on the positive pressure chamber 2.

This power supply device is the positive pressure chamber (2) is blocked when the input shaft (4) is advanced by the pressure of the brake pedal (not shown) and the transformer chamber (3) is in communication with the atmosphere ) And the pressure difference chamber 3 occurs. This pressure difference moves the power piston 6 and the valve device which partitions the constant pressure chamber 2 and the transformer chamber 3 toward the output shaft 7 to press the output shaft 7 so that an output amplified than the input is produced. .

In addition, the power supply apparatus maintains a predetermined gap C1 between the tip of the plunger 8 and the reaction disk 9 in a state before the plunger 8 is pressed by the input shaft 4. Therefore, at the beginning of the braking operation, the front end of the plunger 8 and the reaction disk 9 are kept in a spaced state, and thus the output may increase rapidly without increasing the input force. This is called the jump-in effect. The jump-in effect is applied until the reaction disc 9 is deformed toward the tip of the plunger 8 as the pressure on the input shaft 4 increases and fills the gap C1 between the plunger 8 (until the moment the reaction disc and the plunger come into contact with each other). ) Occurs. This jump-in effect allows quick braking when the driver operates the brake pedal.

The above-described brake booster allows the jump in effect to occur by maintaining the gap C1 between the reaction disc 9 and the plunger 8 tip before or during the braking operation. However, such a power system has a problem that it is difficult to increase the jump-in effect because the jump-in effect is limited to the initial braking operation and there is a limit to increase the gap due to structural problems. In particular, there was a limit to increase the braking effect in the case of emergency braking.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a brake power boosting device which can quickly improve the output of the power boosting device when performing a long braking.

The brake power supply apparatus according to the present invention for achieving the above object is to communicate with the constant pressure chamber and the transformer chamber, the constant pressure chamber and the transformer chamber in accordance with the operation of the input shaft or the transformer chamber is in communication with the atmosphere and the positive pressure And a valve device for pressurizing the output shaft while moving by a pressure difference between the chamber and the transformer chamber, wherein the valve device includes a first channel for communicating the constant pressure chamber and the transformer chamber and a second channel for communicating the transformer chamber with the atmosphere. A plunger having a valve body provided, a plunger provided in the valve body to retreat with the input shaft and selectively opening and closing the first and second flow paths, and an elastic material interposed between the valve body and the output shaft. Coupled to the plunger tip to press the disc and the reaction disc in the retraction direction of the plunger Retractable pressure piston and a locking device for maintaining the pressure piston is restrained by the plunger during normal braking and to release the restraint of the pressure piston during emergency braking to allow the pressure piston to retreat relatively a predetermined section. do.

The pressure piston includes a cylindrical portion coupled to the outer surface of the plunger to be retractable, and the locking device includes at least one restraint ball installed to be radially retractable in the cylindrical portion, and the restraint ball may be caught. A locking groove formed on the outer surface of the plunger and the restricting ball are installed on the outer side of the cylindrical portion to retreat in the retracting direction of the plunger so as to be caught by the locking groove or released. It includes a control ring having a step surface for, and the adjustment spring for pressing the control ring in the pressing direction of the plunger.

The boosting apparatus further includes a support cylinder installed in the valve body for transmitting the pressing force of the valve body to the reaction disk and supporting the pressure piston in a retractable manner.

The adjustment ring is characterized in that the front end is in contact with the support cylinder to limit the advancement of the restraint of the restraining ball.

The pressure piston is characterized in that the movement in the opposite direction of the operation direction of the plunger when the restraint by the restraint ball is released.

The brake power booster according to the present invention may allow the pressure piston to retreat a predetermined section relatively while maintaining the state in which the pressure piston is restrained by the plunger during normal braking by the operation of the locking device and the restriction of the pressure piston is released during emergency braking. . Therefore, when the emergency braking is performed, the jump-in phenomenon is increased, so that the output of the power plant can be quickly improved.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the brake booster according to the present invention divides the sealed cell 10 and the inner space of the cell 10 into a front positive pressure chamber 11 and a rear transformer chamber 12 at a rear side thereof. The power piston 13 and the diaphragm 14 provided in the inside of 10 are provided. The pipe 15 provided on the front of the cell 10 is connected to an external negative pressure source (such as an intake manifold of the vehicle). Therefore, the constant pressure chamber 11 is maintained at low pressure.

An opening 16 is provided in the rear center of the cell 10, and the opening 16 is provided with a positive pressure chamber 11 and a transformer chamber according to an operation of an input shaft 17 connected to a brake pedal (not shown) of a vehicle driver's seat. The pressure between the positive pressure chamber 11 and the transformer chamber 12 is caused by the communication between the positive pressure chamber 11 and the transformer chamber 12 and the transformer chamber 12 in communication with the atmosphere. The valve device 20 which makes a difference arise is provided.

2 and 3, the valve device 20 is installed inside the hollow valve body 21 and the valve body 21, the plunger (opening and closing the flow path in accordance with the operation of the input shaft 17 ( 22) and poppet valves (23).

The valve body 21 is supported by the opening 16 at the rear of the cell 10 so as to be retractable, and the power piston 13 and the diaphragm 14 are fixed to the outer surface of the tip portion entering the cell 10. Therefore, the valve body 21 moves forward and backward with the power piston 13 when the power piston 13 moves forward due to the pressure difference between the positive pressure chamber 11 and the transformer chamber 12.

In front of the valve body 21 inside the cell 10 is provided an output shaft 18 which penetrates the center of the cell 10 and is connected to a master cylinder (not shown), and the rear end of the output shaft 18 is elastically deformed. Possible reaction disk 25 is coupled to the valve body 21 via. For this coupling, a cup-shaped coupling portion 24 is provided at the rear end of the output shaft 18, and the reaction disk 25 is accommodated in the cup-shaped coupling portion 24. In addition, a restoring spring 19 for providing restoring force to the valve body 21 is provided outside the output shaft 18.

The valve body 21 includes a first flow path for communicating the constant pressure chamber 11 and the transformer chamber 12, and a second flow path for communicating the transformer chamber 12 with the atmosphere. The first flow path is formed in the longitudinal direction on the outer side of the hollow portion 26 so as to communicate with the positive pressure chamber 11, and in the radial direction of the hollow portion 26 to communicate with the transformer chamber 12. The formed second communication path 28 is a flow path that is formed when communicating with each other through the hollow portion 26, the second flow path air inlet in the rear end of the valve body 21 in the state in which the first communication path 27 is blocked It is a flow path formed when the 29 and the second communication path 28 communicate with each other through the hollow portion 26.

The poppet valve 23 and the plunger 22 installed in the hollow portion 26 of the valve body 21 selectively open these first flow passages and the second flow passages as the input shaft 17 moves forward and backward. The plunger 22 is coupled to the front end of the input shaft 17 and retracts with the input shaft 17, and has an opening and closing portion 30 for opening and closing the flow path while being in contact with or spaced apart from the front end of the poppet valve 23. The poppet valve 23 is fixed to the inner surface of the valve body 21 outside the input shaft 17 and is provided in the form of a corrugated pipe that can be expanded and contracted.

8, the poppet valve 23 is pushed backward by the opening / closing portion 30 at the rear end of the plunger 22 when the input shaft 17 is retracted, as shown in FIG. 8. By opening 27, the constant pressure chamber 11 and the transformer chamber 12 communicate with each other, and at the same time, the introduction of outside air is blocked by the contact between the opening and closing portion 30 and the tip of the poppet valve 23. Therefore, at this time, both the positive pressure chamber 11 and the transformer chamber 12 are in a negative pressure state, so that the valve body 21 is pushed backward by the elasticity of the restoring spring 19.

When the input shaft 17 moves forward, as shown in FIG. 6, the contact between the poppet valve 23 and the plunger 22 opening / closing part 30 is released, and the poppet valve 23 extends forward to form a first communication path. At the same time as closing (27), the air inlet 29 at the rear end of the valve body 21 communicates with the second communication path 28 by the separation between the opening and closing portion 30 and the poppet valve 23. Therefore, at this time, since the positive pressure chamber 11 is maintained at the negative pressure state and the atmosphere flows into the transformer chamber 12, the power piston 13 inside the cell 10 is caused by the pressure difference between the positive pressure chamber 11 and the transformer chamber 12. It is pushed toward this constant pressure chamber 11. When the power piston 13 is pushed toward the positive pressure chamber 11, the valve body 21 also moves forward so that the valve body 21 pushes the output shaft 18 with great force.

As shown in FIG. 2, the support pin 31 is fitted into the second communication path 28 of the valve body 21. The support pin 31 prevents the inner end of the plunger 22 and the input shaft 17 from being coupled to the inside of the valve body 21 by being caught by the locking groove 32 of the plunger 22, and the outer end of the support pin 31. It catches on the inner surface of the cell 10 to limit the retraction of the valve body 21.

In addition, the valve body 21 is provided with a pressing piston 40 coupled to the tip of the plunger 22 to pressurize the reaction disk 25. The pressing piston 40 is coupled to the rear end of the cylindrical portion 41 to the front end side of the plunger 22 to be retractable. That is, the tip of the plunger 22 enters into the cylindrical part 41 and is coupled. The outer surface of the pressure piston 40 is interposed between the valve body 21 and the reaction disk 25 and supported by the support cylinder 50 provided in a cylindrical shape so as to be able to move forward and backward. The support cylinder 50 is fixed to the valve body 21 in a state where the front end is in contact with the rear circumference of the reaction disk 25 and the rear end is in contact with the valve body 21. Therefore, the support cylinder 50 transmits the pressing force when the valve body 21 moves forward to the reaction disk 25. An o-ring 51 for sealing is installed between the support cylinder 50 and the inner surface of the valve body 21. Here, this embodiment exemplified a form in which the pressure piston 40 is supported by the support cylinder 50. However, the pressure piston 40 may be supported by a structure (support means) directly formed in the valve body 21 in the same form as the support cylinder 50.

The pressing piston 40 is coupled to the front end portion of the plunger 22 by the locking device 60 provided on the cylindrical portion 41 to be restrained or restrained. This allows the gap C2 of the tip of the pressing piston 40 and the reaction disk 25 to be adjusted according to the pressure of the plunger 22. The locking device 60 for this operation is a plurality of through holes 61 formed in the radial direction in the cylindrical portion 41, the restraining ball 62 is installed in each of the through holes 61 in the radial direction to be retracted, restraining balls A locking groove 65 formed on the outer surface of the plunger 22 so that a part of the 62 can be caught, and the outer side of the cylindrical portion 41 so that the restraint ball 62 is caught in the locking groove 65 or the locking is released. And a cylindrical adjustment ring 63 provided to be able to move forward and backward in the direction of retraction of the plunger 22, and an adjustment spring 64 for pressing the adjustment ring 63 in the pressure direction of the plunger 22.

As shown in FIG. 4, the adjustment ring 63 has a plurality of stepped surfaces 63a and 63b for restraining and restraining the restraining ball 62. In more detail, the stepped surfaces 63a and 63b include a constrained surface 63a having a relatively small inner diameter so as to constrain the constrained ball 62, and a constrained surface having a larger inner diameter than the constrained surface 63a. A release surface 63b. As shown in FIG. 3, the adjustment ring 63 restrains the restraining surface 63a by pressing the restraining ball 62 toward the plunger 22 when the restraining ball 62 is in contact with the restraining surface 63a. As illustrated in FIG. 7, the restraint ball 62 is released when the restraint ball 62 is in contact with the restraint release surface 63b. When the restraint of the restraint ball 62 is released, the pressing piston 40 is able to move in the opposite direction to the pressing direction of the plunger 22.

As shown in FIG. 3, the adjustment spring 64 is supported by the first spring support 67 provided at one end of the plunger 22, and the other end is supported by the second spring support 68 provided at the adjustment ring 63. Supported.

The following describes the operation of the brake booster.

When a normal braking operation (not emergency braking) is performed, as shown in FIG. 5, the plunger 22 is advanced as the input shaft 17 enters, and the opening and closing portion 30 of the plunger 22 is the poppet valve 23. At the same time, the poppet valve 23 blocks the first communication path 27.

Therefore, at this time, communication between the constant pressure chamber 11 and the transformer chamber 12 is blocked, and the transformer chamber 12 and the air communicate with each other, so that the pressure of the transformer chamber 12 increases. When the power piston 13 is advanced by the pressure difference between the constant pressure chamber 11 and the transformer chamber 12 according to the pressure rise of the transformer chamber 12, the valve body 21 is also advanced while pressing the output shaft 18. Allow braking. At this time, since the pressing piston 40 maintains the state where the restraint ball 62 is caught in the locking groove 65 of the plunger 22, the pressing piston 40 advances with the plunger 22 to pressurize the reaction disc 25. In addition, the reaction disk 25 is deformed by the pressing of the support cylinder 50 so that the rear center portion is deformed to enter the support cylinder 50.

In the initial stage of the normal braking operation, as shown in FIG. 3, the gap C2 exists between the tip of the pressure piston 40 and the reaction disk 25, so that the output is substantially identical even though the input through the input shaft 17 is substantially the same. Rises sharply. This phenomenon occurs until the point where the tip of the pressure piston 40 and the reaction disk 25 are in contact with each other, which is called a jump-in phenomenon. In the graph of FIG. 9, the section F0 shows a state in which the output sharply increases due to the initial jump-in phenomenon.

As shown in FIG. 5, a pressure difference between the positive pressure chamber 11 and the transformer chamber 12 is generated from the moment when the tip of the pressure piston 40 and the reaction disk 25 deformed into the support cylinder 50 are in contact with each other. The force forward of the valve body 21 and the force transmitted from the input shaft 17 to the pressure piston 40 act as braking force. At this time, the output for the input is increased in proportion to the F1-F2 section of the graph of FIG.

As such, when the braking is performed and emergency braking is required and the driver presses the input shaft 17 with a greater force, as shown in FIG. 6, the plunger 22 and the pressurizing piston 40 of the valve body 21 Advance faster than forward speed. Therefore, at this time, the front end of the adjustment ring 63 outside the pressure piston 40 is in contact with the rear end of the support cylinder 50, the advance of the adjustment ring 63 is limited. Therefore, at this time, since the restraint of the restraint ball 62 by the adjusting ring 63 is restrained, the restraint of the pressing piston 40 is restrained by the restraint ball 62. Therefore, at this time, as shown in FIG. 7, the pressure piston 40 retreats relatively with respect to the plunger 22, and the adjustment ring 63 also retreats with the pressure piston 40 relatively slightly. As described above, while the pressing piston 40 is relatively retreated, the second jump, which causes the output ratio to the input to rise rapidly, occurs. At this time, as the clearance gap between the opening and closing portion 30 of the plunger 22 and the poppet valve 23 becomes larger, the inflow of outside air toward the transformer chamber 12 becomes smoother. This second jump-in phenomenon shows a sharp increase in the output to the input as in the F2-F3 section in the graph of FIG. Therefore, braking can be performed more quickly.

On the other hand, such a power booster is immediately switched to the state of FIG. 7 when urgent braking is performed by rapidly pressing the input shaft 17 at the initial braking operation. That is, since the pressing piston 40 retreats relatively a predetermined section due to the emergency braking, the jump-in effect generated at the beginning of the braking operation is greatly increased. In other words, the first jump-in phenomenon mentioned above and the second jump-in phenomenon appear together in the initial braking operation. When emergency braking is performed from the beginning of the braking operation as described above, the initial jump-in phenomenon increases as in the section of F0 in the graph of FIG. 10. Therefore, when the emergency braking is performed, it is possible to quickly improve the output of the power plant in the initial braking operation.

When the braking is released, as shown in FIG. 8, the position of the pressing piston 40 is restored to the initial state as the input shaft 17 and the plunger 22 retreat. In this state, the pressure piston 40 enters the restraint ball 62 into the engaging groove 65 of the plunger 22 and the restraint surface 63a of the adjustment ring 63 presses the restraint ball 62. Is bound to 22. In this case, since the opening / closing portion 30 of the plunger 22 contacts the poppet valve 23 and pushes the poppet valve 23 backward, the inflow of air is blocked and the first communication path 27 is opened while the positive pressure chamber ( 11) and the transformer chamber 12 communicate with each other. Therefore, at this time, since the pressures in the constant pressure chamber 11 and the transformer chamber 12 are equal, the valve body 21 is retracted by the elasticity of the restoring spring 19, and the output shaft 18 is retracted by the retraction of the valve body 21. Retreat also.

1 is a cross-sectional view of a conventional brake booster.

2 is a cross-sectional view of the brake booster according to the present invention.

3 is a cross-sectional view of the valve device of the brake booster according to the present invention.

4 is a cross-sectional view of the pressure piston and the adjustment ring of the brake booster according to the present invention.

5 is a cross-sectional view of main parts of the brake booster according to the present invention, and shows a state in which general braking is performed.

6 and 7 are cross-sectional views of main parts of the brake power booster according to the present invention, each showing a state in which emergency braking is performed step by step.

8 is a cross-sectional view of the main portion of the brake power booster according to the present invention, showing a brake release state.

9 is a graph showing a change in output with respect to the input of the brake power booster according to the present invention, showing the first jump-in phenomenon and the second jump-in phenomenon during normal braking.

10 is a graph showing a change in output with respect to the input of the brake power booster according to the present invention, showing a state in which the initial jump-in phenomenon is greatly improved during emergency braking.

Explanation of symbols on the main parts of the drawings

10: cell 11: constant pressure chamber

12: transformer chamber 13: power piston

14: diaphragm 17: input shaft

18: output shaft 19: restoring spring

20: valve device 21: valve body

22: Plunger 23: Poppet Valve

25: Reaction disc 27: First communication path

28: second communication path 30: seat portion

40: pressure piston 41: cylindrical portion

50: support cylinder 60: locking device

62: restraint ball 63: adjustment ring

64: adjusting spring 65: locking groove

Claims (5)

The cell 10 having the constant pressure chamber 11 and the transformer chamber 12 and the constant pressure chamber 11 and the transformer chamber 12 communicate with each other according to the operation of the input shaft 17 or the transformer chamber 12. It includes a valve device 20 for communicating with the atmosphere and pressurizing the output shaft 18 while moving by the pressure difference between the constant pressure chamber 11 and the transformer chamber 12, The valve device 20 has a valve body 21 having a first flow path for communication between the constant pressure chamber 11 and the transformer chamber 12 and a second flow path for communication with the transformer chamber 12 and the atmosphere. And a plunger 22 installed in the valve body 21 to retreat with the input shaft 17 and having an opening and closing portion for selectively opening and closing the first and second flow paths, and the valve body 21 and the An elastic reaction disk 25 interposed between the output shaft 18 and a pressure piston 40 coupled to the plunger tip to pressurize the reaction disk 25 and capable of advancing and retracting in the retracting direction of the plunger; When the normal braking, the pressing piston 40 is restrained by the plunger 22, and during the emergency braking, the restraining device of the pressing piston 40 is released so that the pressing piston 40 retreats relatively predetermined section. Including (60), The pressure piston 40 includes a cylindrical portion 41 coupled to the outer surface of the plunger 22 in a retractable manner, and the locking device 60 is installed in the cylindrical portion 41 in a radially retractable manner. At least one restraint ball 62, a catching groove 65 formed on an outer surface of the plunger 22 so that a part of the restraining ball 62 is caught, and the restraining ball 62 are provided at the catching groove 65. Adjusting ring having a stepped surface for restraining and releasing the restraint ball 62 on the inner surface is installed in the retracted direction of the plunger 22 in the outer side of the cylindrical portion 41 in order to be caught or released And a control spring (64) for pressing the control ring (63) in the pressing direction of the plunger (22). delete The method of claim 1, It further comprises a support cylinder (50) installed in the valve body 21 to transfer the pressing force of the valve body 21 to the reaction disk 25 and to support the pressure piston 40 to be retractable Brake booster. The method of claim 3, The adjustment ring (63) is a brake power booster, characterized in that the front end is in contact with the support cylinder (50) to limit the restraint of the restraint ball (62). The method of claim 1, The pressure piston (40) is a brake booster, characterized in that when the restraint by the restraint ball 62 is released in the opposite direction of the operation of the plunger (22).

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