JP2006273214A - Pneumatic booster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic booster capable of enhancing the responsiveness of a braking device by setting the stroke of an output rod to be larger than that of an input rod. <P>SOLUTION: A valve body 9 is connected to a power piston 5 to demarcate a constant pressure chamber 7 and a variable pressure chamber 8. A plunger 16 is moved by an input rod 22 and a poppet valve 21 is opened to introduce the atmosphere into the variable pressure chamber 8. The power piston 5 and the valve body 9 are advanced by the differential pressure between the variable pressure chamber 8 and the constant pressure chamber 7 constantly maintained at the negative pressure, the servo force is given to an output rod 14 via a reaction disk 13, and a part of the reaction force is fed back to an input rod 22 via the reaction disk 13. During braking, the poppet valve 21 is opened by a part of the reaction force from the reaction disk 13 via a rod 37 to set the stroke of the output rod 14 to be larger than that of the input rod 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic booster that can be used in a brake device of a vehicle such as an automobile.

In general, a brake device of an automobile is equipped with a pneumatic booster to increase the braking force. As described in, for example, Patent Document 1, a general pneumatic booster includes a constant pressure chamber (which is constantly maintained at a negative pressure by engine intake negative pressure) and a variable pressure chamber inside a housing by a power piston. The air pressure (positive pressure) is introduced into the variable pressure chamber by moving the plunger provided in the valve body connected to the power piston by the input rod, so that there is a difference between the constant pressure chamber and the variable pressure chamber. Pressure is generated, and the thrust generated in the power piston due to this differential pressure is applied to the output rod via the reaction member, and part of the reaction force that acts on the reaction member from the output rod is fed back to the input rod. ing.
JP 2004-001632 A

  And the brake device of a motor vehicle operates the piston of a master cylinder with the output rod of the above-mentioned pressure type booster, generates brake fluid pressure, and supplies this fluid pressure to a wheel cylinder via brake piping. Then, the piston is operated to press the brake pad or the like against the disc rotor or the like to generate a braking force.

  At this time, the brake fluid pressure generated in the master cylinder is supplied to the wheel cylinder, and a certain amount of brake fluid is supplied from the master cylinder to the wheel cylinder until the piston is activated and the braking force actually rises. Since this is necessary, this becomes a loss stroke, and the stroke amount of the input rod (ie, brake pedal) of the pneumatic booster increases accordingly. Therefore, in the above-described pneumatic booster, a clearance (jump-in clearance) is provided between the reaction member and the plunger that presses the reaction member, and the reaction force from the output rod does not act on the input rod in the initial stage of braking. Thus, by reducing the brake operation force, the braking force rises quickly (jump-in characteristic).

  However, in the conventional pneumatic booster, as shown by the broken line in FIG. 6, the stroke of the input rod and the stroke of the output rod are linearly proportional. It is necessary to increase the stroke of the input rod only, and there is a problem in the response of the brake device.

  The present invention has been made in view of the above points, and an object thereof is to provide a pneumatic booster capable of increasing the stroke of the output rod with respect to the stroke of the input rod.

The invention according to claim 1 defines the inside of the housing as a constant pressure chamber and a variable pressure chamber by a power piston, and moves the plunger disposed in the valve body connected to the power piston by an input rod, thereby Opening and introducing working gas into the variable pressure chamber, generating a differential pressure between the constant pressure chamber and the variable pressure chamber, generating a thrust in the power piston by this differential pressure to advance the valve body, A thrust is applied to the output rod via the reaction member, a part of the reaction force acting on the reaction member is transmitted from the output rod to the input rod, and the valve means is closed by the advancement of the valve body. In a pneumatic booster designed to be valved,
Valve opening means for opening the valve means by a part of the reaction force from the reaction member is provided.
A pneumatic booster according to a second aspect of the present invention is the rod according to the first aspect, wherein the valve opening means has a predetermined moving range interposed between the reaction member and the valve means. It is characterized by including.

According to the pneumatic booster of the first aspect of the present invention, at the time of braking, the valve means is opened by a part of the reaction force from the reaction member by the valve opening means, so that the valve means is closed. The moving distance of the valve body increases, and the stroke of the output rod can be increased with respect to the input rod.
According to the pneumatic booster of the second aspect of the invention, the valve means can be opened via the rod by a part of the reaction force from the reaction member, and the valve means can be opened by the movement range of the rod. The valve can be controlled.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the pneumatic booster 1 according to the present embodiment includes a front shell 2 and a rear shell 3 coupled together to form a housing 4. The housing 4 includes a power piston 5 and a diaphragm. 6, a constant pressure chamber 7 and a variable pressure chamber 8 are defined. A front end portion of a substantially cylindrical valve body 9 is inserted and connected to the power piston 5 in an airtight manner, and a rear end side of the valve body 4 passes through the variable pressure chamber 6 and is airtightly connected to the cylindrical portion 3A of the rear shell 3. It is slidably inserted and extended to the outside. A seal member 10 and a dust cover 11 are provided between the cylindrical portion 3A and the valve body 9. A connection pipe 12 is attached to the front shell 2, and the connection pipe 12 is connected to a negative pressure source (not shown) such as an intake pipe of the engine so that the constant pressure chamber 7 is always maintained at a predetermined negative pressure. The

  A proximal end portion of the output rod 14 is connected to a front end portion of the valve body 9 in the constant pressure chamber 7 via a reaction disk 13 (reaction member), and the distal end portion of the output rod 14 is airtightly connected to the front shell 2. It is slidably inserted and extended to the outside. The distal end portion of the output rod 14 is connected to a piston of a master cylinder (not shown) attached to the front shell 2 side.

  A reaction rod 15 that abuts on the reaction disk 13 and a plunger 16 that abuts on the reaction rod 15 are slidably guided in a small-diameter portion formed at the front portion in the valve body 9. A cylindrical movable seat member 17 is guided by a seal 18 in an airtight and slidable manner at a large diameter portion formed at the rear portion in the valve body 9. Further, a poppet valve 21 is attached to the inner wall of the large-diameter portion of the valve body 9, and the poppet valve 21 is attached to the seat portion 19 formed at the rear end portion of the plunger 16 and the rear end portion of the movable seat member 17. The seat portion 20 is formed and detached from the seat portion. The plunger 16 is connected to the distal end portion of the input rod 22, and the proximal end portion of the input rod 22 is inserted through a breathable dust seal 23 attached to the rear end portion of the valve body 9 and extended to the outside. Yes. A brake pedal (not shown) is connected to the proximal end portion of the input rod 22.

  A constant pressure passage 24 that communicates with the constant pressure chamber 7 and atmospheric passages 25 and 26 that communicate with the variable pressure chamber 8 are provided on the side wall of the valve body 9, and the plunger 16 and the movable seat member 17 move to move the seat of the plunger 16. When the portion 19 and the poppet valve 21 are separated from each other, the atmospheric passages 25 and 26 are communicated with and blocked from the atmosphere, and the seat portion 20 of the movable seat member 17 and the poppet valve 21 are separated from each other. The constant pressure passage 24 and the atmospheric passages 25 and 26 are communicated and blocked. As a result, the seat portion 19 of the plunger 16, the seat portion 20 of the movable seat member 17, and the poppet valve 21 constitute valve means for introducing the atmosphere as working gas into the variable pressure chamber 8.

  A stop key 27 is inserted into the atmospheric passage 25 of the valve body 9, and the stop key 27 engages with a step portion 28 of the rear shell 3 to limit the retracted position of the valve body 9. Engages with the outer peripheral groove 29 of the plunger 16 to limit the relative movement range of the valve body 9 and the plunger 16.

  A return spring 30 is provided between the front shell 2 and the valve body 9 to urge the valve body 9 to the retracted position. Between the retainer 31 that is attached to the inner peripheral surface of the valve body 9 and fixes the poppet valve 21 and the input rod 22, a return spring 32 that biases the input rod 22 to the retracted position is provided. A valve spring 33 that urges the poppet valve 21 toward the plunger 16 and the movable seat member 17 is provided between the metal core 21 </ b> A of the poppet valve 21 and the input rod 22. A spring 35 is provided between the seat portion 19 of the plunger 16 and the movable seat member 17 to press the movable seat member 17 to the shoulder portion 34 between the large diameter portion and the small diameter portion of the valve body 9. Yes. When the valve body 9 and the input rod 22 are in the retracted position, a predetermined gap C (jump-in clearance) is formed between the reaction disk 13 and the reaction rod 15.

  A guide hole 36 extending in the axial direction is provided on the side wall of the large-diameter portion of the valve body 9 from the end contacting the reaction disk 13 to the shoulder 34 contacting the movable seat member 17. A rod 37 (valve opening means) whose both ends abut against the reaction disk 13 and the movable sheet member 17 is slidably inserted into 36. The diameter of the guide hole 36 and the end of the rod 37 on the reaction disk 13 side is increased to form step portions 36A and 37A, and a gap L is provided between these step portions 36A and 37A. The movement range is limited, and the movable sheet member 17 can be moved from the position on the reaction disk 13 side by the gap L.

Next, the operation of the present embodiment configured as described above will be described.
In the non-braking state, as shown in FIG. 2, the movable seat member 17 contacts the shoulder portion 34, and the poppet valve 21 is seated on the seat portion 19 of the plunger 16 and the seat portion 20 of the movable seat member 17. Since the atmospheric passages 25 and 26 are blocked from the negative pressure passage 24 and the atmosphere, the pressures in the constant pressure chamber 7 and the variable pressure chamber 8 are maintained in a balanced state, and no thrust is generated in the power piston 5.

  When the input rod 22 is advanced by the brake pedal, as shown in FIG. 3, the plunger 16 is advanced, the seat portion 19 is separated from the poppet valve 21, and the atmospheric passages 25, 26 are communicated with the atmosphere. Air is introduced into the chamber 8. As a result, a differential pressure is generated between the constant pressure chamber 7 and the variable pressure chamber 8 that are always maintained at a negative pressure. Due to this differential pressure, a thrust is generated in the power piston 5 and the valve body 9 moves forward, causing the reaction disk 13 to move forward. Then, the output rod 14 is advanced to press the piston of the master cylinder to generate a braking force. When the valve body 9 moves forward, the poppet valve 21 is seated on the seat portion 19 of the plunger 16, shuts off the air passages 25 and 26, and the differential pressure between the constant pressure chamber 7 and the variable pressure chamber 8 is maintained.

  At this time, part of the reaction force of the force acting on the output rod 14 from the valve body 9 via the reaction disk 13 is fed back to the brake pedal via the reaction rod 15, the plunger 16 and the input rod 22. Thereby, a braking force can be generated according to the operating force of the brake pedal.

  In the initial stage of braking, the reaction rod 15, the plunger 16, and the input rod 22 can move forward without receiving a reaction force from the reaction disk 13 due to the gap C between the reaction desk 13 and the reaction rod 15. Therefore, the braking force can be quickly started up (jump-in action).

  When the reaction disk 13 is compressed by the reaction force from the master cylinder, the reaction disk 13 presses the rod 37 in the guide hole 36 and retracts as shown in FIG. As a result, the rod 37 protrudes from the shoulder portion 34 to retract the movable seat member 17, and the poppet valve 21 is separated from the seat portion 19 of the plunger 16. As a result, the atmosphere passages 25 and 26 communicate with the atmosphere, the atmosphere is introduced into the variable pressure chamber 8, and a thrust is generated in the power piston 5. As shown in FIG. It moves forward until it seats on the 16 seat portions 19. As a result, as shown by the solid line in FIG. 6, the stroke of the output rod 14 becomes larger than the stroke of the input rod 22, thereby eliminating the loss stroke of the brake device and improving the response of the brake device. Can do. As shown in FIG. 5, after the rod 37 is retracted by the gap L and the stepped portion 37A comes into contact with the stepped portion 36A of the guide hole 36, the retracting of the rod 37 is stopped. The increase in the stroke of the rod 14 is released (see point P in FIG. 6).

  When the input to the input rod 22 is released, the input rod 22 and the plunger 16 are retracted by the return spring 32 and the spring 35, the seat portion 19 of the plunger 16 presses the poppet valve 21, and the seat portion 20 of the movable seat member 17. Separate from. As a result, the constant pressure passage 24 and the atmospheric passages 25, 26 communicate with each other, the pressure difference between the constant pressure chamber 7 and the variable pressure chamber 8 is eliminated, the thrust of the power piston 5 disappears, and the valve body 9 is attached to the return spring 30 by the valve spring 9. Reverses and braking is released. The rod 37 is returned to the original position by the spring 35 when the deformation of the reaction disk 13 is eliminated by releasing the brake.

1 is a longitudinal sectional view of a pneumatic booster according to an embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view of a main part showing a non-braking state in the apparatus of FIG. 1. FIG. 2 is an enlarged longitudinal sectional view of a main part showing an initial braking state in the apparatus of FIG. 1. FIG. 2 is an enlarged longitudinal sectional view of a main portion showing a state in which the movable seat member is retracted and the poppet valve is separated from the seat portion of the plunger in the apparatus of FIG. 1. FIG. 3 is an enlarged longitudinal sectional view of a main part showing a state in which the retracting of the movable seat member is stopped and the poppet valve is seated on the seat portion of the plunger in the apparatus of FIG. 1. It is a graph which shows the relationship between the stroke of the input rod of the apparatus of FIG. 1, and the stroke of an output rod.

Explanation of symbols

1 Pneumatic Booster, 4 Housing, 5 Power Piston, 7 Constant Pressure Chamber, 8 Transformer Chamber, 9 Valve Body, 13 Reaction Disc (Reaction Member), 14 Output Rod, 16 Plunger, 19 Seat (Valve Means), 20 Seat part (valve means), 21 Poppet valve (valve means), 22 Input rod, 37 Rod (valve opening means)

Claims (2)

The inside of the housing is defined as a constant pressure chamber and a variable pressure chamber by a power piston, and a plunger disposed in a valve body connected to the power piston is moved by an input rod, thereby opening valve means and operating gas in the variable pressure chamber. To generate a differential pressure between the constant pressure chamber and the variable pressure chamber, to generate a thrust to the power piston by this differential pressure to advance the valve body, and to output the thrust through the reaction member Actuating the rod, a part of the reaction force acting on the reaction member from the output rod is transmitted to the input rod, and the valve means is closed by the advancement of the valve body. Force device,
A pneumatic booster comprising valve opening means for opening the valve means by a part of the reaction force from the reaction member. 2. The pneumatic booster according to claim 1, wherein the valve opening means includes a rod having a predetermined movement range interposed between the reaction member and the valve means.

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