JPH1159397A - Brake booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake booster capable of providing a brake characteristic with a lineaer pedaling feel. SOLUTION: A valve body 28 provided in a power piston is provided with a guide cylinder 51 guiding a push rod 64, and a sleeve 55 guided by the guide cylinder 51 is provided in a position where a reaction plate 86 make contact therewith; when the sleeve 55 is pushed by the pushing force of the reaction plate 86, its amount of movement is limited by the valve body 28, and an elastic body 57 providing a resilient force in the direction of movement of the sleeve 55 is inserted into the sleeve 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master cylinder which is disposed between a brake pedal to which a driver's treading force is applied and a master cylinder which converts the treading force into hydraulic pressure, and which increases the treading force applied to the brake pedal. To a brake booster for transmitting to a vehicle.

[0002]

2. Description of the Related Art In general, a brake device for a vehicle is provided with a brake booster for the purpose of increasing the braking force by increasing the driver's depression force applied to a brake pedal.

As a conventional brake booster, a negative pressure type brake booster utilizing a differential pressure between negative pressure and atmospheric pressure is used. The boosting characteristics of this negative pressure type brake booster
It has a linear characteristic as shown by a line a in FIG. By the way, it is generally known that the brake characteristic becomes an upwardly convex non-linear graph as shown in FIG. When the boosting characteristics and the braking characteristics of the negative pressure type brake booster are combined, the deceleration increases as the output increases, as shown by the line c in FIG. 11C.
When the output exceeds a certain level, there is a tendency that the manner of elongation of the deceleration decreases and the effectiveness of the brake decreases. Speaking of the pedal operation feeling, it gives a heavy feeling to the driver when sudden braking is applied.

Therefore, as shown by a line b in FIG. 11 (A), a negative pressure type brake booster in which the boosting factor is increased in the vicinity where the effectiveness of the brake is reduced to increase the degree of the treading force is increased. (Treading force-deceleration characteristic) is as shown in FIG.
As shown by the d-line, the linear operation becomes almost linear, and a linear pedal operation feeling can be obtained.

[0005]

As described above, a negative pressure type brake booster is required to make its boosting characteristic nonlinear in accordance with the braking characteristic in order to make the driver feel a corresponding braking expectation. Is required. Tokuhei 3-83
Japanese Patent Application Laid-Open No. 06-192736 and Japanese Patent Application Laid-Open No. 8-192736 disclose a device that makes the boost characteristics non-linear. However, it is difficult to obtain predetermined boost characteristics matching various brake characteristics. was there. Therefore, a feeling of linear pedal operation could not be obtained.

Accordingly, an object of the present invention is to provide a brake booster having a predetermined boosting characteristic such that a linear pedal operation feeling can be obtained.

[0007]

According to a first aspect of the present invention, there is provided a tread force transmitting means for transmitting a tread force of a driver, and brake generating means receiving the pressing force of the tread force transmitting means. Output means 12 for boosting and transmitting the pressing force of the treading force transmitting means 11 in accordance with the pressing force of the treading force transmitting means 11, and the boosting means 13 and the valve means 14 are provided to the output means 12. The valve means 14 is opened by the treading force transmitting means 11, and provides a boost corresponding to the pressing force of the treading force transmitting means 11 to the boosting means 13.
In the brake booster 10 that closes the valve when the brake force occurs, the booster 13 includes a guide 15 that holds the pedaling force transmitting unit 11, and the booster 13 has a boost factor of the booster 13. It is characterized in that a boost factor setting means 16 which can be adjusted in advance is provided.

The boost factor setting means 16 includes a moving guide means 17 provided along the longitudinal direction of the guide means 15, a tip end surface of the moving guide means 17 and the pedaling force transmitting means 11.
A reaction means 18 disposed between the end face of the actuator and the output means 12 for applying a reaction force to the treading force transmitting means 11, and a limiting means 19 for limiting the amount of movement of the movement guide means 17
And a resilient means 20 for generating a pressing force for the movement when the movement guide means 17 is moved by the reaction means 18 between the restricting means 19 and the movement guide means 17 ( Claim 2).

According to a third aspect of the present invention, the housing 25 is divided into a constant pressure chamber 38 connected to a negative pressure source and a constant pressure chamber 38 or a variable pressure chamber 40 connected to the atmosphere. The valve body 28 provided with the valve means 70 is connected to the power piston 32 to be formed.
8 is provided with an input rod 46 penetrating the valve means 70 and connected to the push rod 64, and the output rod 5 penetrating through the constant pressure chamber 38 concentrically facing the push rod 64.
A brake booster in which a reaction plate 86 formed of an elastic body is disposed between the output rod 56 and the tip of the push rod 64. Body 2
8, a guide cylinder 51 for guiding the push rod 64 is provided, and a sleeve 55 guided by the guide cylinder 51 is provided at a position where the reaction plate 86 comes into contact with the sleeve 55. The sleeve 55 is pushed by the pressing force of the reaction plate 86. The amount of movement is limited by the valve body 28,
It is characterized in that an elastic body 57 for giving a repulsive force in the moving direction is inserted.

The power piston 32 of the output rod 56
It is preferable that an enlarged diameter portion 56A is provided on the side, and the enlarged diameter portion 56A covers both the reaction plate 86 and the sleeve 55 (claim 4). It is preferable that the elastic body 57 that applies a pressing force to the sleeve 55 with which the reaction plate 86 abuts is a metal elastic body 57 (Claim 5). It is preferable that the metal elastic body 57 be a metal coil elastic body 57 (claim 6). The sleeve 15 with which the reaction plate 186 contacts.
It is preferable that the elastic member 157 that applies a pressing force to the fifth member is a metal bamboo child spring 157 (claim 7). It is preferable that the elastic body 257 that applies a pressing force to the sleeve 255 with which the reaction plate 286 abuts is a metal or non-metallic disc spring 257 (claim 8). Cuts 257a, 257 from inside or outside of the disc spring 257
7b is preferable (claim 9).

[0011] The invention of claim 10 for solving the above-mentioned problems is as follows.
A valve body provided with a valve device is connected to a power piston that divides the inside of the housing into a constant-pressure chamber connected to a negative pressure source and a constant-pressure chamber or a variable-pressure chamber connected to the atmosphere to form a constant pressure chamber. An input rod that penetrates the valve device of the body and is connected to the push rod is provided, and an output rod that penetrates the constant-pressure chamber concentrically facing the push rod is disposed. In a brake booster in which a reaction plate formed of an elastic body is disposed between the front end and a front end, a guide cylinder 351 for guiding the push rod is provided on a valve body provided on the power piston. A recess 351A having an opening on one side is provided on the reaction plate side, and a sleeve 355 is provided on the opening side of the recess 351A.
Are slidably disposed, and the sleeve 355 and the recess 351 are arranged.
An elastic body 357A made of rubber is provided with a gap 359A that can move when the sleeve 355 is pressed by the reaction plate 386.

The reaction plate 386 of the guide cylinder
A concave portion 351A with one side opening on the side has a stepped portion having a reaction plate 386 of the guide cylinder 351 and two side surfaces opened on the outer periphery thereof, and the outer periphery of this stepped portion is covered with the enlarged diameter portion 356A of the output rod. It is preferable to adopt a configuration (claim 11). It is preferable that the concave portion 451A whose one side surface is opened on the reaction plate 486 side of the guide cylinder 451 be configured to be opened only in the reaction plate 486 of the guide cylinder 451 (claim 12). It is preferable that the sleeve 455 to be inserted into the recess 451A of the guide cylinder 451 and the elastic body 457 be bonded (claim 13). It is preferable that the hardness of the reaction plate 486 and the hardness of the elastic body 457 disposed in the concave portion 451A be different from each other (claim 14).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a brake system including a brake booster 10 according to the embodiment.

As shown in FIG. 1, a brake booster 10 includes a brake pedal 1 supported so as to be swingable around a support shaft, and a hydraulic pressure for converting a pedaling force applied to the brake pedal 1 to a hydraulic pressure. It is arranged between the master cylinder 2 as a conversion means. The master cylinder 2 is connected to a cylinder of a brake device 3 such as a disc brake or a drum brake via a brake pipe or the like. The master cylinder 2 and the brake device 3 constitute a brake generating means.

The brake booster 10 includes a pedaling force transmitting means (push rod) 11 for transmitting the driver's pedaling force.
Output means (output rod) for receiving the pressing force of the treading force transmitting means 11 and boosting and transmitting the pressing force of the treading force transmitting means 11 to the brake generating means 2, 3 in accordance with the pressing force of the treading force transmitting means 11. ) 12, and a booster 13 and a valve 14 are connected to the output 12, and the valve 14 is opened by the pedaling force transmitting unit 11, and the pushing force of the pedaling force transmitting unit 11 is opened. Boosting means 13 corresponding to
The booster 13 is provided with a guiding means 15 for holding the treading force transmitting means 11.
The guide means 15 is provided with a boost factor setting means 16 capable of adjusting the boost factor of the boost means in advance.

The boost factor setting means 16 includes a moving guide means 17 provided along the longitudinal direction of the guiding means 15, a tip end face of the moving guiding means 17, an end face of the pedaling force transmitting means, and the output means 12. Treading force transmitting means 1 disposed between
Reaction means 18 for giving a reaction force to the actuator 1, a limiting means 19 for limiting the amount of movement of the movement guiding means 17, and the movement guiding means 17 between the limiting means 19 and the movement guiding means 17 by the reaction means 18. Resilient means 20 for generating a pushing force when moved
It is composed of

The guide means 15 is provided with a movement guide means 17 and a resilient means 20, and the movement guide means 17 moved by the reaction means 18 moves to the limiting means 19 against the pressing force of the resilient means 20. Therefore, the point at which the boost factor changes can be changed by changing the pressing force of the resilient means 20. Further, by using the spring means 20 having various linear or non-linear spring constants, the manner of curve at the point where the boost factor changes can be changed rapidly or gently. As a result, it is possible to obtain predetermined boosting characteristics that match various braking characteristics.

The structure of the above-described brake booster 10 will be described in detail below. FIG. 2 shows a brake booster 10.
Is shown. Note that an appropriately indicated arrow FR indicates a front side of the vehicle, and an arrow UP indicates an upper side of the vehicle.

As shown in FIG. 2, the brake booster 10 includes a housing 25 including a front shell 22 and a rear shell 24, and has a flat cylindrical shape as a whole. The front shell 22 has a bottomed cylindrical main body portion 22A, and a cylindrical protruding portion 22B protruding rearward of the vehicle is formed at the bottom wall axis of the main body portion 22A. The rear shell 24 has a dish-shaped base 24A,
A cylindrical protruding portion 24B protruding toward the rear side of the vehicle is formed at the axis of the base portion 24A. The main body 22A of the front shell 22 is provided with a negative pressure introduction port 26 that communicates with an intake manifold (not shown).

A power piston 32 comprising a valve body 28 and a diaphragm plate 30 is accommodated in the rear shell 24 so as to be movable in the axial direction. The valve body 28 has a main body portion 28A having a larger diameter than the protruding portion 24B of the rear shell 24, and an intermediate portion formed to protrude from the axial center portion of the main body portion 28A toward the vehicle rear side and having a smaller diameter than the protruding portion 24B. 28B, and a cylindrical portion 2 protruding from the outer peripheral portion of the intermediate portion 28B toward the vehicle rear side.
8C. The rear end of the cylindrical portion 28C further projects from the projecting portion 24B of the rear shell 24, and the space between both rear ends is covered with a boot 34.

On the other hand, the diaphragm plate 30 is formed in a dish shape having a hole in the shaft core, and the periphery of the hole is integrated with the valve body 28 by being engaged with the main body 28A of the valve body 28. ing. On the outer surface of the diaphragm plate 30, a diaphragm 36 is stretched. The inner end of the diaphragm 36 is fixed to the outer peripheral surface of the main body 28A of the valve body 28,
The outer end of the diaphragm 36 is fixed between the rear end of the front shell 22 and the outer end of the rear shell 24. Thereby, the front shell 22 and the rear shell 24
Is separated by a diaphragm 36 into a constant pressure chamber 38 in which a predetermined negative pressure acts and a variable pressure chamber 40 in which the negative pressure changes to atmospheric pressure.

The protruding portion 22B of the front shell 22
A return spring 44 is interposed between the outer periphery of the valve body 28 and the main body 28A of the valve body 28. Therefore, the return spring 44 constantly urges the power piston 32 toward the base 24A of the rear shell 24.

Further, a human-powered rod 46 is disposed in the cylindrical portion 28C of the valve body 28 described above. The rear end of the human-powered rod 46 is connected to a brake pedal (not shown) via a clevis 48. Therefore, when a pedaling force is applied to the brake pedal, the human-powered rod 46 moves axially toward the front of the vehicle. Further, an assembly 52 of a silencer and an air filter is provided between the axially intermediate portion of the human-powered rod 46 and the rear end of the cylindrical portion 28C. Further, a valve device 6 described later is provided on the distal end side of the human-powered rod 46.
0 is provided.

On the other hand, the main body 28A of the valve body 28
A guide cylinder 51 protrudes from a restriction surface 52 at the shaft core. The limiting surface 52 is provided in the concave portion 53 of the valve body 28.
And the guide cylinder 51 has a structure located at the center in the concave portion 53. A sleeve 55 guided around the outer periphery of the guide cylinder 51 is slidably fitted. Sleeve 55
An elastic body 57 in the form of a coil spring is interposed between the elastic member 57 and the restricting surface 52 so as to give a repulsive force in a moving direction when the sleeve 55 is pressed by a pressing force of a reaction plate 86 described later. I have. Further, the movement amount when the sleeve 55 is pressed by the pressing force of the reaction plate 86 is limited by the restriction surface 52.

In the recess 53 of the valve body 28,
An output rod 56 for accommodating a reaction plate 86 described in detail later is provided. The output rod 56
The reaction plate 86 is inserted into the recess 53 and the reaction plate 86.
Enlarged portion 56A having a recess for accommodating the
And a rod portion 56B protruding from the shaft core portion 6A and penetrating the protruding portion 22B of the front shell 22. The distal end portion of the rod portion 56B can press a piston (not shown) arranged in the master cylinder 2 (see FIG. 1). Note that a seal member 58 is provided on the bottom of the protruding portion 22B of the front shell 22.

Next, the valve device 60 will be described. FIG.
As shown in FIG.
Is formed with another concave portion 62 at a position facing the concave portion 53 of the main body portion 28A, and a push rod 64 is accommodated in the concave portion 62. The push rod 64 includes a main body 64A slidably disposed within the concave portion 62, and a main body 28A through a neck portion 64B from an axis of the main body 64A.
Pressing portion 64C protruding toward the concave portion 53 side of the main body 6
The air valve 64D is formed so as to protrude toward the input rod 46 so as to cover a spherical portion provided at the distal end of the input rod 46 from the axis of 4A.

Returning to FIG. 2, the aforementioned push rod 64
A passage 68 is formed in a predetermined portion (a portion facing the atmosphere valve 64D) in the intermediate portion 28B of the valve body 28 corresponding to the above. One end of the passage 68 is open to the variable pressure chamber 40, and the other end is open to the concave portion 62 of the intermediate portion 28 </ b> B of the valve body 28. Thereby, the internal space of the cylindrical portion 28C of the valve body 28 and the
0 can be communicated.

A rubber poppet 70 is disposed at the rear end of the push rod 64 at the rear end of the atmosphere valve 64D. The poppet 70 has a ring-shaped front end, a cylindrical rear end, and a flexible intermediate portion connecting the both.
Returning to FIG. 2, a retainer 72 having a two-stage cylindrical section is provided on the rear end side of the poppet 70.
A return spring 76 is interposed between 2 and the spring seat 74 of the input rod 46. For this reason,
The return spring 76 constantly presses the retainer 72 toward the push rod 64, whereby the poppet 70
Is sandwiched between the retainer 72 and a step formed on the inner peripheral surface of the cylindrical portion 28C. On the other hand, poppet 7
A ring-shaped retainer 78 is fitted inside the front end of the “0”, thereby providing a predetermined rigidity to the front end (hereinafter, this front end is referred to as “vacuum valve 70A”). . A return spring 80 is interposed between the retainer 78 and the spring seat 74. For this reason, the return spring 80 constantly urges the vacuum valve 70A of the poppet 70 toward the intermediate portion 28B of the valve body 28. A valve seat 82 is formed on the pressing direction side of the vacuum valve 70A.
The outer periphery of 0A is pressed against the valve seat 82 by the urging force of the return spring 80.

In correspondence with the poppet 70 described above, a negative pressure passage 84 is formed in the main body 28A and the intermediate part 28B of the valve body 28. One end of the negative pressure passage 84 is opened into the constant pressure chamber 38, and the other end is opened near the valve seat 82 of the poppet 70 with which the vacuum valve 70 </ b> A contacts. Normally, the vacuum valve 70A is slightly open, and the constant pressure chamber 38 and the atmospheric pressure chamber 40 are normally connected.

Here, in the above-described brake booster 10, the reaction plate 86 fitted and held in the enlarged-diameter portion 56A of the output rod and the configuration related thereto will be described in detail with reference to FIG.

The reaction plate 86 is formed in a disk shape having a predetermined outer dimension a, and has an enlarged diameter portion 56 of the output rod.
A is fitted in a concave portion 56C having a predetermined inner diameter dimension a formed in A. The reaction plate 86 is made of rubber having a predetermined hardness, and distributes and transmits a reaction force from the master cylinder 2 (FIG. 1) to the power piston 32 and the push rod 64 when the brake is actuated, so that a predetermined boosting factor is obtained. In addition to having a function of obtaining a predetermined jumping function, the reaction plate and the push rod 64 are brought into a non-contact state at the time of an initial low pedaling force to exert a predetermined jumping function.

A rear end of the reaction plate 86 is slidably guided by a front end of the guide cylinder 51 having a predetermined outer dimension c and a predetermined inner diameter b and an outer periphery of the guide cylinder 51, and has a predetermined outer dimension a. The structure is such that the front end of the sleeve 55 having the inner diameter c is in contact with the sleeve 55. The sleeve 55 is covered with the reaction plate 86 by the enlarged diameter portion 56A. A distance 1 is provided between the rear end of the sleeve 55 and the regulating surface 52. Therefore, the push rod 64
When pressed between the front end of the guide tube 51 and the front end of the guide tube 51 and the bottom surface 56D of the recess 56C of the output rod, the reaction plate 86 expands between the inside diameter of the recess 56C and the outside diameter of the guide tube 51. And pushes the sleeve 51 backward by overcoming the urging force of the elastic body 57.
At the time of 2, the distance 1 becomes zero.

Next, the operation of this embodiment will be described. When the brake is not operated without applying the pedaling force to the brake pedal 1 (FIG. 1), as shown in FIG.
2 is pushed back (to the right in the drawing) to the bottom position of the base 24A of the rear shell 24 by the urging force of the return spring 44. In this state, the input rod 46 and the push rod 64 are pushed back to the initial position (to the right in the drawing) by the urging force of the return spring 76. Further, at this time, the urging force of the return spring 80 pushes the vacuum valve 70A of the poppet 70 back (to the left in the drawing) until it contacts the atmospheric valve 64D of the push rod 64. As a result, the vacuum valve 70 of the poppet 70
A and the valve seat 82 are in a non-contact state, and a predetermined gap is formed between the two (see FIG. 3). Therefore, both the negative pressure valve (the negative pressure inlet 26 or a check valve provided in the pipeline connected thereto) and the vacuum valve 70A are open, and the atmospheric valve 64D is closed. For this reason, since the negative pressure from the intake manifold (not shown) acts on both the constant pressure chamber 38 and the variable pressure chamber 40, there is no pressure difference between the two chambers. That is, the brake booster 10 is in a non-operating state. In this state, as shown in FIG.
Although the pressing portion 64C of the push rod 64 is located in the center hole 88 of the guide cylinder 51, the reaction plate 86
Is in non-contact with the rear end face.

When a slight depression force is applied to the brake pedal 1 (FIG. 1) from this state, the power piston 32 is still at the initial position as shown in FIG. As a result, the front end face of the pressing portion 64C of the push rod 64 comes into contact with the rear end face of the reaction plate 86. Therefore, the urging force of the return spring 80 causes the vacuum valve 70A of the poppet 70 to move following the atmospheric valve 64D of the push rod 64 and abut on the valve seat 82. Therefore, since the negative pressure passage 84 is closed by the vacuum valve 70A, no negative pressure is introduced into the variable pressure chamber 40 after this point. In this case, the pedaling force applied to the brake pedal 1 (FIG. 1)
4, transmitted to the output rod via the reaction plate 86. That is, the brake booster 10 is in an operation start state.

When further depressing force is applied to the brake pedal 1 from this state, as shown in FIG. 4, the output rod is further pushed to the left in the figure, and the atmospheric valve 64D of the push rod 64 is connected to the vacuum valve 70A of the poppet 70. Separate from.
For this reason, the atmosphere is reduced to the air filter / silencer assembly 5.
2, is introduced into the cylindrical portion 28 </ b> C, and is further introduced into the transformation chamber 40 through the passage 68. As a result, a pressure difference occurs between the constant pressure chamber 38 and the variable pressure chamber 40. Accordingly, the power piston 32 moves to the left side in the figure from the point in time when this pressure difference exceeds the urging force of the return spring 44. In this case, the pedaling force applied to the brake pedal 1 is
The input rod 46 is transmitted to the reaction plate 86 via both the push rod 64 and the power piston 32, and further transmitted to the output rod. As a result, the pedaling force applied to the brake pedal 1 by the driver is increased (boosted). That is, this state is the brake booster 1
0 is the operating state.

Here, looking at the state of the reaction plate 86 in this case, in the low pedaling force range (low input range), FIG.
(A) As shown in FIG.
It is in a state of slightly swelling with the inner periphery of the inner concave portion 56C. The swelling portion of the swelling reaction plate 86
Overcoming the biasing force of the elastic body 57, the sleeve 55 is moved toward the restriction surface 52. In this state, when the pedal force is further increased, the reaction force from the master cylinder 1 increases, and as shown in FIG.
The swelling of the reaction plate 86 continues until the sleeve 55 guided by the outer circumference of the first plate 1 hits the limiting surface 52. Therefore, the contact area between the rear end surface of the reaction plate 86 and the valve body 28 including the front end of the guide cylinder 51 and the restriction surface 52 is different between the low pedal effort region and the high pedal effort region.

As shown in FIGS. 5A and 5B,
The area A of the inner diameter a of the concave portion 56C in the diameter portion 56A is A = a
^Two× π / 4, outside the pressing portion 64C of the input rod 64.
Area B of diameter b is A = b^Two× π / 4, and the guide cylinder 51
The area C of the outer diameter c is ^Two× π / 4. In FIG.
In the low pedaling force range shown in the input-output diagram, the input rod 46
Ratio of the input to the output rod of the motor (the so-called servo ratio [times
Power factor]) R is R = C / B. Input-output diagram of FIG.
In the high pedaling force range, the servo ratio [boost factor]) R is
A / B. That is, the servo ratio R is small in the low pedaling force range.
It becomes large in the high pedaling force area. Low and high pedal effort
Is a break point P.

As a result, the boosting characteristic of the brake booster 10 according to this embodiment is a line graph with a downward convex as shown in FIG. In general, as shown in FIG. 11B, the brake characteristic is an upwardly convex non-linear graph. Therefore, when the boost characteristic of the brake booster 10 according to the present embodiment and the conventional brake characteristic are viewed together. In the present embodiment, however, the boosting factor increases in the vicinity where the braking effect decreases, and the degree of increase in the pedaling force increases. As a result, according to the present embodiment, the braking characteristic (pedal force-deceleration characteristic) is
As shown in FIG. 11 (C), it becomes almost linear, and a linear pedal operation feeling is obtained.

In this embodiment, a sleeve 55 and an elastic body 57 for obtaining the break point P shown in FIG. 6 are slidably fitted on the outer periphery of the guide cylinder 51, and the enlarged diameter portion 56 at the rear end of the output rod is provided.
Since the reaction plate 86 is accommodated in A, the selectivity of the dimensions a, b, and c that determine the boost factor is expanded. For example, the diameter of the reaction plate 86 can be increased. Due to the presence of the sleeve 55 and the elastic body 57, even if the reaction plate 86 becomes large, the movement of the sleeve 55 according to the degree of swelling can be ensured.
By changing the elastic modulus of the elastic body 57, there is an advantage that the position of the break point P in FIG. 6 can be changed.

In particular, the position of the bending point P and the degree of bending in FIG. 6 are important to obtain a linear pedal operation feeling as shown in FIG. It is effective to slidably fit the outer periphery of 51 to provide a variable element. An example of characteristic adjustment by changing the elastic body will be described with reference to FIGS.

FIG. 7 shows a case in which a metal bamboo child spring 157 is used as the elastic body. As shown in FIG. 7B, the bamboo child spring 157 is formed by winding a leaf spring having a predetermined width w into a bamboo child shape, and when pressed, becomes a metal body having the thickness of the predetermined width w. That is, as shown in FIG.
Even if the sleeve 155 is formed in a ring shape, it can be compressed to a predetermined width w to form a metal integrated structure. Therefore, the sleeve 15
5 and the structure of the combination of the bamboo child spring 157 are simplified. In addition, a stepped portion having two side surfaces is provided at the front end of the guide tube 151, and the enlarged diameter portion 156 </ b> A covering the stepped portion forms a concave portion 151 </ b> A opening toward the reaction plate 86. Since the sleeve 155 and the bamboo shoot spring 157 are fitted into the concave portion 151A on the outer peripheral portion of the front end of the guide cylinder 151, the mounting can be simplified.

FIG. 8 shows a case in which a disc spring 257 made of metal or nonmetal is used as the elastic body. The disc spring 257 has elasticity until the oblique ring is pressed flat. With such a structure, not only metal but also elastic nonmetallic resin or rubber can be used.
The elastic modulus can be easily changed by forming notches 257a radially from the inside as shown in FIG. 8C, not limited to a simple oblique ring shape as shown in FIG. 8B. As shown in FIG. 8D, cuts 2 are formed radially from the outside.
57b can be inserted. As shown in FIG. 8E, the number of radial cuts 257c from the outside is increased, and the protrusion 257d between the cuts 257c and the cuts 257c.
May have a rounded chrysanthemum washer shape. The thickness dimension of the disc spring 257 in FIG. 8A is also determined when the disc spring 257 is crushed flat, and a sleeve 255 having a simple shape can be used. In addition, various types of disc springs having a shape shown in FIG. 8E having an elastic modulus close to a linear characteristic can be appropriately selected from the shape shown in FIG. It is. The configuration in which the concave portion 251A is formed jointly with the stepped portion of the outer peripheral portion of the front end of the guide cylinder 251 and the enlarged diameter portion 256A is the same as that in FIG.

As shown in FIG. 9, a rubber elastic body such as synthetic rubber can be used as the elastic body. Rubber elastic body 35
7A is a gap 359A so that it can be deformed and move when pressed.
Is provided. The gap 359A is a U-shaped groove on the inner and outer circumferences, and the cross section of the rubber elastic body 357A has a drum shape. By changing the cross section of the rubber elastic body to provide various gaps, the elastic modulus can be selected in various forms of non-linearity. FIG.
As shown in (B), a gap 359B having a rectangular cross section may be provided on the rubber elastic body 357B so that the change in the initial elastic modulus is increased and the elastic characteristic in which the change in the elastic modulus in the latter half is suppressed. As shown in FIG. 9C, the rubber elastic body 357C is formed by making the regulating surface 352C of the rubber elastic body 357C oblique.
A predetermined elastic characteristic can be obtained with both the shape of the control surface 352C and the shape of the control surface 352C. As shown in FIG. 9D, a rubber elastic body 357 is formed.
The cross section of D is made narrower toward the rear.
By making the cross section of the rubber elastic body 357E into a semicircle as in (E), it is possible to make the change in the elastic modulus non-linear with an upward convexity. As shown in FIG. 9A, the inner diameter of the enlarged diameter portion 356A of the push rod 356 and the two
A reaction plate 35 is provided between the step portion and the side portion.
A concave portion 351A having one side surface opened on the 8 side is formed to accommodate the rubber elastic body 357A and the sleeve 355, so that the concave portion 351A can be easily formed. The entire structure of the brake booster other than the illustration is the same as that described with reference to FIGS.

FIG. 10 shows a modification of the recess when a rubber elastic body is used as the elastic body. A concave portion 451A that opens only on the reaction plate 458 side on the tip end surface of the guide cylinder 451.
May be formed, and the rubber elastic body 557 and the sleeve 455 may be housed in the recess 451A. The shape of the recess 451A is uniquely determined. It is also preferable to bond the reaction plate 458 and the sleeve 455 so that the attitude of the sleeve 455 with respect to the rubber elastic body 557 does not change. Also, the rubber hardness of the reaction plate 458 and the rubber hardness of the rubber elastic body 557 can be made different from each other to change the elastic modulus (spring constant) of the rubber elastic body 557.

[0045]

According to the first and second aspects of the present invention, the guide means 15 is provided with the movement guide means 17 and the resilient means 20, and the movement guide means 17 moved by the reaction means 18 reduces the pressing force of the resilient means 20. Since it is configured to move to the limiting means 19 in opposition, by changing the pressing force of the resilient means 20,
The point at which the boost factor changes can be changed.
By using a linear or non-linear spring having various spring constants, it is possible to change the curve at the point where the boost factor changes, so that a predetermined boosting characteristic matching various braking characteristics can be obtained. Can be.

According to the third to ninth aspects of the present invention, the sleeve 55 and the elastic body 57 for obtaining the break point P of the boost factor are slidably fitted on the outer periphery of the guide cylinder 51, and the rear end of the output rod is provided. Since the reaction plate 86 is accommodated in the enlarged diameter portion 56A, the selectivity of the dimensions a, b, and c that determine the servo ratio can be increased. For example, the diameter of the reaction plate 86 can be increased. Sleeve 55
And the presence of the elastic body 57, the reaction plate 8
Even if the size of the sleeve 6 becomes large, the sleeve 5 according to the degree of bulging
5 movements can be secured. By changing the elastic modulus of the elastic body 57, the position of the break point P can be changed. As a result, it is possible to obtain predetermined boosting characteristics that match various braking characteristics.

According to the tenth to fourteenth aspects of the present invention, since a rubber elastic body such as synthetic rubber is used, the elastic modulus can be varied in various non-linear forms by changing the cross section of the rubber elastic body to provide various gaps. Can be selected. As a result, it is possible to obtain predetermined boosting characteristics that match various brake pad characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a structure of a brake booster of the present invention.

FIG. 2 is a sectional view of a brake booster of the present invention.

FIG. 3 is an enlarged sectional view of a main part of the brake booster in FIG. 2;

FIG. 4 is an enlarged sectional view of a main part showing an operation of the brake booster of the present invention.

FIG. 5 is an enlarged sectional view showing a swelling state of a reaction plate.

FIG. 6 is a graph showing a boost factor change of the brake booster of the present invention.

FIG. 7 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 8 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 9 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 10 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 11 is a graph showing a change in a boost factor required for a brake booster.

[Explanation of symbols]

 2 Master cylinder (brake generating means) 3 Brake device (brake generating means) 11 Treading force transmitting means 12 Output means 13 Boosting means 14 Valve means 15 Guide means 16 Boost factor setting means 17 Moving guide means 18 Reaction means 19 Limiting means 20 Resilient means 26 housing 28 valve body 32 power piston 38 constant pressure chamber 40 variable pressure chamber 51 guide cylinder 55 sleeve 56 output rod 56A enlarged diameter portion 57 elastic body 64 push rod 70 valve means 86 reaction plate 157 bamboo spring 257 dish spring 257a, 257b Notch 351A Recess 357A Rubber elastic body 359A Gap 356A Large diameter portion 451A Recess 457 Rubber elastic body

[Procedure amendment]

[Submission date] November 2, 1998

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[Document name to be amended] Drawing

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[Document Name] Statement

[Title of the Invention] Brake booster

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates] is disposed between the master cylinder for converting a brake pedal, a pedal pressure depression force of the driver is applied to the hydraulic, the master and enhance granted depression force to the brake pedal The present invention relates to a brake booster transmitting to a cylinder.

[0002]

2. Description of the Related Art Generally, a brake device of an automobile is provided with a brake booster for the purpose of increasing a driver 's treading force applied to a brake pedal to increase a braking force.

As a conventional brake booster, a negative pressure type brake booster utilizing a differential pressure between negative pressure and atmospheric pressure is used. The boosting characteristics of this negative pressure type brake booster
It has a linear characteristic as shown by a line a in FIG. By the way, it is generally known that the brake characteristic becomes an upwardly convex non-linear graph as shown in FIG. When the boosting characteristics and the braking characteristics of the negative pressure type brake booster are combined, the deceleration increases as the output increases, as shown by the line c in FIG. 11C.
When the output exceeds a certain level, there is a tendency that the manner of elongation of the deceleration decreases and the effectiveness of the brake decreases. Speaking of the pedal operation feeling, it gives a heavy feeling to the driver when sudden braking is applied.

Therefore, as shown by a line b in FIG. 11 (A), a negative pressure type brake booster which increases the boosting factor in the vicinity where the braking effect is reduced to increase the degree of the stepping force is increased. (Treading force-deceleration characteristic) is as shown in FIG.
As shown by the d-line, the linear operation becomes almost linear, and a linear pedal operation feeling can be obtained.

[0005]

As described above, in the negative pressure type brake booster, the boosting characteristic is made non-linear in accordance with the brake characteristic in order to make the driver feel a sense of expectation of braking. Is required. Tokuhei 3-8306
Japanese Patent Application Laid-Open No. 8-192736 and Japanese Patent Application Laid-Open No. 8-192736 disclose a device having a nonlinear boosting characteristic. However, there is a problem that it is difficult to obtain a predetermined boosting characteristic matching various brake characteristics. there were. Therefore, a feeling of linear pedal operation could not be obtained.

Accordingly, an object of the present invention is to provide a brake booster having a predetermined boosting characteristic such that a linear pedal operation feeling can be obtained.

[0007]

According to a first aspect of the present invention, there is provided a tread force transmitting means for transmitting a tread force of a driver.
1, and transmits the booster the pushing force of the treading force transmission means 11 in accordance with the pressing force of the brake force <br/> generated hand the the stage treading force transmission means 11 receives the pressing force of the treading force transmission means 11 Output means 12
And the output means 12 has a booster 13
And connecting the valve means 14 and, the valve means 14 is opened by the treading force transmission means 11, the booster means 1
In the brake booster 10 that closes when a boost corresponding to the pressing force of the treading force transmitting means 11 is generated by the step 3, the boosting means 13 includes a guide means 15 for holding the treading force transmitting means 11. , characterized in that a booster ratio setting means 16 which can be pre-adjusted boosting factor of the guide means 15 doubles power unit 13.

The boost factor setting means 16 includes a moving guide means 17 provided along the longitudinal direction of the guide means 15, a tip end surface of the moving guide means 17 and the pedaling force transmitting means 11.
A reaction means 18 disposed between the end face of the actuator and the output means 12 for applying a reaction force to the treading force transmitting means 11, and a limiting means 19 for limiting the amount of movement of the movement guide means 17
And a resilient means 20 for generating a pressing force for the movement when the movement guide means 17 is moved by the reaction means 18 between the restricting means 19 and the movement guide means 17 ( Claim 2).

According to a third aspect of the present invention, a housing 25 is divided into a constant pressure chamber 38 connected to a negative pressure source and a constant pressure chamber 38 or a variable pressure chamber 40 connected to the atmosphere. A valve body 28 having a valve device 60 is connected to the power piston 32 to be formed, and an input rod 46 that penetrates the valve device 60 and is connected to a push rod 64 is provided. A brake booster comprising an output rod 56 penetrating through the constant pressure chamber 38 and a reaction plate 86 formed of an elastic body disposed between the output rod 56 and the tip of the push rod 64. in the guide tube 51 for guiding the push rod 64 before Kiba Rububodi 28
The provided provided a sleeve 55 which is guided by the guide tube 51 to the position where the reaction plate 86 strikes, the sleeve 55, the amount of movement when pressed by pressing force of the reaction plate 86 in the valve body 28 Elastic body 5 that restricts and gives repulsive force in the moving direction
Characterized in that the insertion of the 7.

The power piston 32 of the output rod 56
It is preferable that an enlarged diameter portion 56A is provided on the side, and the enlarged diameter portion 56A covers both the reaction plate 86 and the sleeve 55 (claim 4). The elastic member 57 to provide a pushing force on the sleeve 55 of the reaction plate 86 abuts, preferably those made of metal (claim 5). The previous Symbol bullet resistant body 57, made of metal coil elastic body 5
7 is preferable (claim 6). The elastic body 57
The, preferably those with metallic bamboo shoot Ba Ne (claim 7). It is preferable that the elastic body 57 is a disc spring 257 made of metal or non-metal (claim 8). The Farewell Ne
It is preferable that cuts 257a and 257b are made from the inside or outside of the slab (claim 9).

[0011] The invention of claim 10 for solving the above-mentioned problems is as follows.
The power piston 32 to form a each partitioned into a variable pressure chamber 40 connected with the constant pressure chamber 38 connected to Haujin grayed 28 to a negative pressure source to the pressure chamber 38 or the atmosphere, a valve body with a valve device 60 28 and the valve body 2
An input rod 46 which push rod 64 passes through the 8 of the valve device 60 is connected is provided, in opposition to the push rod 64 coaxially will place the output rod 56 that passes through the pressure chamber, the output rod in the brake booster formed by placing the reaction plate 86 which is formed of an elastic body between 56 and distal end of the push rod 64 is provided with a guide tube 351 for guiding the push rod 64 before Kiba Rububodi 28 A concave portion 35 having an open side surface on the reaction plate 386 side of the guide cylinder 351.
1A, a sleeve 355 is slidably disposed on the side surface on the opening side of the recess 351A, and an elastic body 357A made of rubber is pressed between the sleeve 355 and the recess 351A by a reaction plate 386. It is characterized in that it is provided with a gap 359A that can be moved.

The reaction plate 386 of the guide cylinder
A concave portion 351A with one side opening on the side has a stepped portion having a reaction plate 386 of the guide cylinder 351 and two side surfaces opened on the outer periphery thereof, and the outer periphery of this stepped portion is covered with the enlarged diameter portion 356A of the output rod. It is preferable to adopt a configuration (claim 11). It is preferable that the concave portion 451A whose one side surface is opened on the reaction plate 486 side of the guide cylinder 451 be configured to be opened only in the reaction plate 486 of the guide cylinder 451 (claim 12). It is preferable that the sleeve 455 to be inserted into the recess 451A of the guide cylinder 451 and the elastic body 457 be bonded (claim 13). It is preferable that the hardness of the reaction plate 486 and the hardness of the elastic body 457 disposed in the concave portion 451A be different from each other (claim 14).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a brake system including a brake booster 10 according to the embodiment.

As shown in FIG. 1, a brake booster 10 includes a brake pedal 1 supported so as to be swingable around a support shaft, and a hydraulic pressure for converting a pedaling force applied to the brake pedal 1 to a hydraulic pressure. It is arranged between the master cylinder 2 as a conversion means. The master cylinder 2 is connected to a cylinder of a brake device 3 such as a disc brake or a drum brake via a brake pipe or the like. The master cylinder 2 and the brake device 3 constitute a braking force generating means.

The brake booster 10 includes a pedaling force transmitting means (push rod) 11 for transmitting the driver 's pedaling force,
Output means (output rod) for receiving the pressing force of the treading force transmitting means 11 and boosting and transmitting the pressing force of the treading force transmitting means 11 to the brake force generating means 2, 3 in accordance with the pressing force of the treading force transmitting means 11. And a power booster 13 and a valve 14 are connected to the output 12, and the valve 14 is opened by the treading force transmitting means 11. When the booster 13 generates a corresponding boost, the valve is closed.
3 is provided with a guide means 15 for holding the treading force transmitting means 11, and provided with a boost factor setting means 16 capable of adjusting the boost factor of the booster in advance.

The boost factor setting means 16 includes a moving guide means 17 provided along the longitudinal direction of the guiding means 15, a tip end face of the moving guiding means 17, an end face of the pedaling force transmitting means, and the output means 12. Treading force transmitting means 1 disposed between
Reaction means 18 for giving a reaction force to the actuator 1, a limiting means 19 for limiting the amount of movement of the movement guiding means 17, and the movement guiding means 17 between the limiting means 19 and the movement guiding means 17 by the reaction means 18. Resilient means 20 for generating a pushing force when moved
It is composed of

The guide means 15 is provided with a movement guide means 17 and a resilient means 20, and the movement guide means 17 moved by the reaction means 18 moves to the limiting means 19 against the pressing force of the resilient means 20. Therefore, the point at which the boost factor changes can be changed by changing the pressing force of the resilient means 20. Further, by using the spring means 20 having various linear or non-linear spring constants, the manner of curve at the point where the boost factor changes can be changed rapidly or gently. This ensures that it is possible to obtain a predetermined boosting properties that meet the various brake characteristics.

The structure of the above-described brake booster 10 will be described in detail below. FIG. 2 shows a brake booster 10.
Is shown. Note that an appropriately indicated arrow FR indicates a front side of the vehicle, and an arrow UP indicates an upper side of the vehicle.

As shown in FIG. 2, the brake booster 10 includes a housing 25 including a front shell 22 and a rear shell 24, and has a flat cylindrical shape as a whole. The front shell 22 has a bottomed cylindrical main body portion 22A, and a cylindrical protruding portion 22B protruding rearward of the vehicle is formed at the bottom wall axis of the main body portion 22A. The rear shell 24 has a dish-shaped base 24A,
A cylindrical protruding portion 24B protruding toward the rear side of the vehicle is formed at the axis of the base portion 24A. The main body 22A of the front shell 22 is provided with a negative pressure introduction port 26 that communicates with an intake manifold (not shown).

A power piston 32 comprising a valve body 28 and a diaphragm plate 30 is accommodated in the rear shell 24 so as to be movable in the axial direction. The valve body 28 has a main body portion 28A having a larger diameter than the protruding portion 24B of the rear shell 24, and an intermediate portion formed to protrude from the axial center portion of the main body portion 28A toward the vehicle rear side and having a smaller diameter than the protruding portion 24B. 28B, and a cylindrical portion 2 protruding from the outer peripheral portion of the intermediate portion 28B toward the vehicle rear side.
8C. The rear end of the cylindrical portion 28C further projects from the projecting portion 24B of the rear shell 24, and the space between both rear ends is covered with a boot 34.

On the other hand, the diaphragm plate 30 is formed in a dish shape having a hole in the shaft core, and the periphery of the hole is integrated with the valve body 28 by being engaged with the main body 28A of the valve body 28. ing. On the outer surface of the diaphragm plate 30, a diaphragm 36 is stretched. The inner end of the diaphragm 36 is fixed to the outer peripheral surface of the main body 28A of the valve body 28,
The outer end of the diaphragm 36 is fixed between the rear end of the front shell 22 and the outer end of the rear shell 24. Thereby, the front shell 22 and the rear shell 24
Is separated by a diaphragm 36 into a constant pressure chamber 38 in which a predetermined negative pressure acts and a variable pressure chamber 40 in which the negative pressure changes to atmospheric pressure.

The protruding portion 22B of the front shell 22
A return spring 44 is interposed between the outer periphery of the valve body 28 and the main body 28A of the valve body 28. Therefore, the return spring 44 constantly urges the power piston 32 toward the base 24A of the rear shell 24.

Further, in the cylindrical portion 28C of the valve body 28 described above, the input rod 46 is arranged. The rear end of the input rod 46 is connected to a brake pedal (not shown) via a clevis 48. Therefore, when the depression force is applied to the brake pedal, the input rod 46 is axially moved toward the front of the vehicle. Further, between the rear end portion of the axially intermediate portion and the tubular portion 28C of the input rod 46, the assembly 52 of the silencer and the air filter is disposed. Further, the front end portion of the input rod 46, described later valve device 6
0 is provided.

On the other hand, the main body 28A of the valve body 28
A guide cylinder 51 protrudes from a restriction surface 52 at the shaft core. The limiting surface 52 is provided in the concave portion 53 of the valve body 28.
And the guide cylinder 51 has a structure located at the center in the concave portion 53. A sleeve 55 guided around the outer periphery of the guide cylinder 51 is slidably fitted. Sleeve 55
An elastic body 57 in the form of a coil spring is interposed between the elastic member 57 and the restricting surface 52 so as to give a repulsive force in a moving direction when the sleeve 55 is pressed by a pressing force of a reaction plate 86 described later. I have. Further, the movement amount when the sleeve 55 is pressed by the pressing force of the reaction plate 86 is limited by the restriction surface 52.

In the recess 53 of the valve body 28,
Output rod 56 it housing is disposed a reaction plate 86 to be described later. The output rod 56 has a concave portion 56A having a concave portion for entering the concave portion 53 and accommodating the reaction plate 86, and an enlarged diameter portion 56A.
Projecting portion 22 of the front shell 22 projected from the shaft
B, and a rod portion 56B penetrating through B. Rod part 56
The tip of B can press a piston (not shown) arranged in the master cylinder 2 (see FIG. 1). Note that a seal member 58 is provided on the bottom of the protruding portion 22B of the front shell 22.

Next, the valve device 60 will be described. FIG.
As shown in FIG.
Is formed with another concave portion 62 at a position facing the concave portion 53 of the main body portion 28A, and a push rod 64 is accommodated in the concave portion 62. The push rod 64 includes a main body 64A slidably disposed within the concave portion 62, and a main body 28A through a neck portion 64B from an axis of the main body 64A.
Pressing portion 64C protruding toward the concave portion 53 side of the main body 6
The air valve 64D is formed so as to protrude toward the input rod 46 so as to cover a spherical portion provided at the distal end of the input rod 46 from the axis of 4A.

Returning to FIG. 2, the aforementioned push rod 64
A passage 68 is formed in a predetermined portion (a portion facing the atmosphere valve 64D) in the intermediate portion 28B of the valve body 28 corresponding to the above. One end of the passage 68 is open to the variable pressure chamber 40, and the other end is open to the concave portion 62 of the intermediate portion 28 </ b> B of the valve body 28. Thereby, the internal space of the cylindrical portion 28C of the valve body 28 and the
0 can be communicated.

A rubber poppet 70 is disposed at the rear end of the push rod 64 at the rear end of the atmosphere valve 64D. The poppet 70 has a ring-shaped front end, a cylindrical rear end, and a flexible intermediate portion connecting the both.
Returning to FIG. 2, a retainer 72 having a two-stage cylindrical section is provided on the rear end side of the poppet 70.
A return spring 76 is interposed between 2 and the spring seat 74 of the input rod 46. For this reason,
The return spring 76 constantly presses the retainer 72 toward the push rod 64, whereby the poppet 70
Is sandwiched between the retainer 72 and a step formed on the inner peripheral surface of the cylindrical portion 28C. On the other hand, poppet 7
A ring-shaped retainer 78 is fitted inside the front end of the “0”, thereby providing a predetermined rigidity to the front end (hereinafter, this front end is referred to as “vacuum valve 70A”). . A return spring 80 is interposed between the retainer 78 and the spring seat 74. For this reason, the return spring 80 constantly urges the vacuum valve 70A of the poppet 70 toward the intermediate portion 28B of the valve body 28. A valve seat 82 is formed on the pressing direction side of the vacuum valve 70A.
The outer periphery of 0A is pressed against the valve seat 82 by the urging force of the return spring 80.

In correspondence with the poppet 70 described above, a negative pressure passage 84 is formed in the main body 28A and the intermediate part 28B of the valve body 28. One end of the negative pressure passage 84 is opened into the constant pressure chamber 38, and the other end is opened near the valve seat 82 of the poppet 70 with which the vacuum valve 70 </ b> A contacts. Normally, the vacuum valve 70A is slightly open, and the constant pressure chamber 38 and the atmospheric pressure chamber 40 are normally connected.

Here, in the above-described brake booster 10, the reaction plate 86 fitted and held in the enlarged diameter portion 56A of the output rod 56 and the structure related thereto will be described in detail with reference to FIG.

The reaction plate 86 has a disk shape having a predetermined outer dimension a, and is fitted in a recess 56C having a predetermined inner diameter a formed in the enlarged diameter portion 56A of the output rod 56 . The reaction plate 86 is made of rubber having a predetermined hardness.
Addition to having the function of obtaining the predetermined boosting ratio to reaction force from the side by distributed and transmitted to the power piston 32 and the push rod 64 (FIG. 1), the reaction plate 86 and the push rod 64 initial low It is provided in order to exert a predetermined jumping function by making it in a non-contact state at the time of pedaling force.

A rear end of the reaction plate 86 is slidably guided by a front end of the guide cylinder 51 having a predetermined outer dimension c and a predetermined inner diameter b and an outer periphery of the guide cylinder 51, and has a predetermined outer dimension a. The structure is such that the front end of the sleeve 55 having the inner diameter c is in contact with the sleeve 55. The sleeve 55 is covered with the reaction plate 86 by the enlarged diameter portion 56A. A distance 1 is provided between the rear end of the sleeve 55 and the regulating surface 52. Therefore, the push rod 64
When the reaction plate 86 is pressed between the front end of the guide cylinder 51 and the front end of the guide cylinder 51 and the bottom surface 56D of the recess 56C of the output rod 56 , the reaction plate 86
The bulges between the outer diameter, extruded sleeve 55 rearwardly, overcoming the biasing force of the elastic body 57, the distance l is zero hit sleeve 55 the restricting surface 52.

Next, the operation of this embodiment will be described. When the brake is not operated without applying the pedaling force to the brake pedal 1 (FIG. 1), as shown in FIG.
2 is pushed back (to the right in the drawing) to the bottom position of the base 24A of the rear shell 24 by the urging force of the return spring 44. In this state, the input rod 46 and the push rod 64 are pushed back to the initial position (to the right in the drawing) by the urging force of the return spring 76. Further, at this time, the urging force of the return spring 80 pushes the vacuum valve 70A of the poppet 70 back (to the left in the drawing) until it contacts the atmospheric valve 64D of the push rod 64. As a result, the vacuum valve 70 of the poppet 70
A and the valve seat 82 are in a non-contact state, and a predetermined gap is formed between the two (see FIG. 3). Therefore, both the negative pressure valve (the negative pressure inlet 26 or a check valve provided in the pipeline connected thereto) and the vacuum valve 70A are open, and the atmospheric valve 64D is closed. For this reason, since the negative pressure from the intake manifold (not shown) acts on both the constant pressure chamber 38 and the variable pressure chamber 40, there is no pressure difference between the two chambers. That is, the brake booster 10 is in a non-operating state. In this state, as shown in FIG.
Although the pressing portion 64C of the push rod 64 is located in the center hole 88 of the guide cylinder 51, the reaction plate 86
Is in non-contact with the rear end face.

[0034] With slight imparting pedaling force from this state to the brake pedal 1 (Fig. 1), as shown in FIG. 4, the power piston 32 is still being positioned in the initial position, the biasing of the output rod 56 return spring 76 Since the push rod 64 is pressed to the left against the force, the front end face of the pressing portion 64C of the push rod 64 contacts the rear end face of the reaction plate 86. Therefore, the urging force of the return spring 80 causes the vacuum valve 70A of the poppet 70 to move following the atmospheric valve 64D of the push rod 64 and abut on the valve seat 82. Therefore, the negative pressure passage 84 is controlled by the vacuum valve 70A.
Is closed, no negative pressure is introduced into the transformation chamber 40 after this point. In this case, the pedaling force applied to the brake pedal 1 (FIG. 1) is applied from the input rod 46 to the output rod 5 via the push rod 64 and the reaction plate 86.
6 is transmitted. That is, the brake booster 10 is in an operation start state.

When further depressing force is applied to the brake pedal 1 from this state, as shown in FIG. 4, the output rod 56 is further pushed to the left in the figure, and the atmospheric valve 64D of the push rod 64 is connected to the vacuum valve of the poppet 70. Separated from 70A. For this reason, the atmosphere is introduced into the cylindrical portion 28C through the air filter / silencer assembly 52, and
8 into the transformer chamber 40. As a result, a pressure difference occurs between the constant pressure chamber 38 and the variable pressure chamber 40. Therefore, the power piston 32 moves to the left side in the figure from the point in time when the force generated by the pressure difference and the pressure receiving area overcomes the urging force of the return spring 44. In this case, granted depression force to the brake pedal 1 is transmitted to the reaction plate 86 through both of the input rod 46 or we push rod 64 and the power piston 32 is transmitted further to the output rod 56. As a result, the pedaling force applied to the brake pedal 1 by the driver is increased (boosted). That is, this state is the operating state of the brake booster 10.

Here, looking at the state of the reaction plate 86 in this case, in the low pedaling force range (low input range), FIG.
(A) As shown in FIG.
It is in a state of slightly swelling with the inner periphery of the inner concave portion 56C. The swelling portion of the swelling reaction plate 86
Overcoming the biasing force of the elastic body 57, the sleeve 55 is moved toward the restriction surface 52. In this state, when the pedal force is further increased to a higher pedaling force region (higher input region), the reaction force from the master cylinder 2 increases, and as shown in FIG.
The swelling of the reaction plate 86 continues until the sleeve 55 guided by the outer circumference of the first plate 1 hits the limiting surface 52. Therefore, the contact area between the rear end surface of the reaction plate 86 and the valve body 28 including the front end of the guide cylinder 51 and the restriction surface 52 is different between the low pedal effort region and the high pedal effort region.

As shown in FIGS. 5A and 5B, the area A of the inner diameter a of the concave portion 56C in the enlarged diameter portion 56A is A = a
² × π / 4, and the pressing portion 64C of the push rod 64
Is B = b ² × π / 4, and the area C of the outer diameter c of the guide cylinder 51 is C = c ² × π / 4. In the low pedaling force range of the input-output diagram of FIG.
R (the so-called servo ratio [power boosting factor]) R between the input from the controller and the output to the output rod 56 is R = C / B. In the high pedaling force range shown in the input-output diagram of FIG. 6, the servo ratio [boost ratio]) R
Is R = A / B. That is, the servo ratio R is small in a low pedal effort region and large in a high pedal effort region. A break point P is between the low pedal effort area and the high pedal effort area.

As a result, the boosting characteristic of the brake booster 10 according to this embodiment is a line graph with a downward convex as shown in FIG. In general, as shown in FIG. 11B, the brake characteristic is an upwardly convex non-linear graph. Therefore, when the boost characteristic of the brake booster 10 according to the present embodiment and the conventional brake characteristic are viewed together. In the present embodiment, however, the boosting factor increases in the vicinity where the braking effect decreases, and the degree of increase in the pedaling force increases. As a result, according to the present embodiment, the braking characteristic (pedal force-deceleration characteristic) is
As shown in FIG. 11 (C), it becomes almost linear, and a linear pedal operation feeling is obtained.

In this embodiment, a sleeve 55 and an elastic body 57 for obtaining the break point P shown in FIG. 6 are slidably fitted on the outer periphery of the guide cylinder 51, and the enlarged diameter portion at the rear end of the output rod 56 is provided. The configuration in which the reaction plate 86 is accommodated in 56A expands the selectivity of the dimensions a, b, and c that determine the boost factor. For example, the diameter of the reaction plate 86 can be increased. Due to the presence of the sleeve 55 and the elastic body 57, even if the reaction plate 86 becomes large, the movement of the sleeve 55 according to the degree of swelling can be ensured. By changing the elastic modulus of the elastic body 57, FIG.
Has the advantage that the position of the break point P can be changed.

In particular, the position of the bending point P and the degree of bending in FIG. 6 are important to obtain a linear pedal operation feeling as shown in FIG. It is effective to slidably fit the outer periphery of 51 to provide a variable element. An example of characteristic adjustment by changing the elastic body will be described with reference to FIGS.

FIG. 7 shows a case in which a metal bamboo child spring 157 is used as the elastic body. As shown in FIG. 7B, the bamboo child spring 157 is formed by winding a leaf spring having a predetermined width w into a bamboo child shape, and when pressed, becomes a metal body having the thickness of the predetermined width w. That is, as shown in FIG.
Even if the sleeve 155 is formed in a ring shape, it can be compressed to a predetermined width w to form a metal integrated structure. Therefore, the sleeve 15
5 and the structure of the combination of the bamboo child spring 157 are simplified. In addition, a stepped portion having two side surfaces is provided at the front end of the guide tube 151, and the enlarged diameter portion 156 </ b> A covering the stepped portion forms a concave portion 151 </ b> A opening toward the reaction plate 86. Since the sleeve 155 and the bamboo shoot spring 157 are fitted into the concave portion 151A on the outer peripheral portion of the front end of the guide cylinder 151, the mounting can be simplified.

FIG. 8 shows a case in which a disc spring 257 made of metal or nonmetal is used as the elastic body. The disc spring 257 has elasticity until the oblique ring is pressed flat. With such a structure, not only metal but also elastic nonmetallic resin or rubber can be used.
The elastic modulus can be easily changed by forming notches 257a radially from the inside as shown in FIG. 8C, not limited to a simple oblique ring shape as shown in FIG. 8B. As shown in FIG. 8D, cuts 2 are formed radially from the outside.
57b can be inserted. As shown in FIG. 8E, the number of radial cuts 257c from the outside is increased, and the protrusion 257d between the cuts 257c and the cuts 257c.
May have a rounded chrysanthemum washer shape. The thickness dimension of the disc spring 257 in FIG. 8A is also determined when the disc spring 257 is crushed flat, and a sleeve 255 having a simple shape can be used. In addition, various types of disc springs having a shape shown in FIG. 8E having an elastic modulus close to a linear characteristic can be appropriately selected from the shape shown in FIG. It is. The configuration in which the concave portion 251A is formed jointly with the stepped portion of the outer peripheral portion of the front end of the guide cylinder 251 and the enlarged diameter portion 256A is the same as that in FIG.

As shown in FIG. 9, a rubber elastic body such as synthetic rubber can be used as the elastic body. Rubber elastic body 35
7A is a gap 359A so that it can be deformed and move when pressed.
Is provided. The gap 359A is a U-shaped groove on the inner and outer circumferences, and the cross section of the rubber elastic body 357A has a drum shape. By changing the cross section of the rubber elastic body to provide various gaps, the elastic modulus can be selected in various forms of non-linearity. FIG.
As shown in (B), a gap 359B having a rectangular cross section may be provided on the rubber elastic body 357B so that the change in the initial elastic modulus is increased and the elastic characteristic in which the change in the elastic modulus in the latter half is suppressed. As shown in FIG. 9C, the rubber elastic body 357C is formed by making the regulating surface 352C of the rubber elastic body 357C oblique.
A predetermined elastic characteristic can be obtained with both the shape of the control surface 352C and the shape of the control surface 352C. As shown in FIG. 9D, a rubber elastic body 357 is formed.
The cross section of D is made narrower toward the rear.
By making the cross section of the rubber elastic body 357E into a semicircle as in (E), it is possible to make the change in the elastic modulus non-linear with an upward convexity. As shown in FIG. 9A, the inner diameter of the enlarged diameter portion 356A of the push rod 356 and the two
A reaction plate 35 is provided between the step portion and the side portion.
A concave portion 351A having one side surface opened on the 8 side is formed to accommodate the rubber elastic body 357A and the sleeve 355, so that the concave portion 351A can be easily formed. The entire structure of the brake booster other than the illustration is the same as that described with reference to FIGS.

FIG. 10 shows a modification of the recess when a rubber elastic body is used as the elastic body. A concave portion 451A that opens only on the side of the reaction plate 458 on the distal end surface of the guide cylinder 451.
May be formed, and the rubber elastic body 557 and the sleeve 455 may be housed in the recess 451A. The shape of the recess 451A is uniquely determined. Further, by bonding the reaction plate 458 and the sleeve 455 is preferably a child so does not change the posture against the rubber elastic body 557 of the sleeve 455. Also, the rubber hardness of the reaction plate 458 and the rubber hardness of the rubber elastic body 557 can be made different from each other to change the elastic modulus (spring constant) of the rubber elastic body 557.

[0045]

According to the first and second aspects of the present invention, the guide means 15 is provided with the movement guide means 17 and the resilient means 20. Since it is configured to move to the limiting means 19 in opposition, by changing the pressing force of the resilient means 20,
The point at which the boost factor changes can be changed.
By using a linear or non-linear spring having various spring constants, it is possible to change the curve at the point where the boost factor changes, so that a predetermined boosting characteristic matching various braking characteristics can be obtained. Can be.

According to the third to ninth aspects of the invention, the sleeve 55 and the elastic body 57 for obtaining the break point P of the boost factor are slidably fitted on the outer periphery of the guide cylinder 51, and the rear end of the output rod 56 is provided. Since the reaction plate 86 is accommodated in the enlarged diameter portion 56A, the selectivity of the dimensions a, b, and c that determine the servo ratio can be expanded. For example, the diameter of the reaction plate 86 can be increased. Due to the presence of the sleeve 55 and the elastic body 57, even if the reaction plate 86 becomes large, the movement of the sleeve 55 according to the degree of swelling can be ensured. By changing the elastic modulus of the elastic body 57, the position of the break point P can be changed. As a result, it is possible to obtain predetermined boosting characteristics that match various braking characteristics.

According to the tenth to fourteenth aspects of the present invention, since a rubber elastic body such as synthetic rubber is used, the elastic modulus can be varied in various non-linear forms by changing the cross section of the rubber elastic body to provide various gaps. Can be selected. As a result, it is possible to obtain predetermined boosting characteristics that match various brake pad characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a structure of a brake booster of the present invention.

FIG. 2 is a sectional view of a brake booster of the present invention.

FIG. 3 is an enlarged sectional view of a main part of the brake booster in FIG. 2;

FIG. 4 is an enlarged sectional view of a main part showing an operation of the brake booster of the present invention.

FIG. 5 is an enlarged sectional view showing a swelling state of a reaction plate.

FIG. 6 is a graph showing a boost factor change of the brake booster of the present invention.

FIG. 7 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 8 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 9 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 10 is an enlarged sectional view of a main part of another brake booster of the present invention.

FIG. 11 is a graph showing a change in a boost factor required for a brake booster.

[EXPLANATION OF SYMBOLS] 2 mass Tashi Linda (braking force generating means) 3 brake device (brake force generating means) 11 treading force transmission means 12 output means 13 times power unit 14 valve means 15 guiding means 16 times power factor setting means 17 moves the guide Means 18 Reaction means 19 Limiting means 20 Resilient means 26 Housing 28 Valve body 32 Power piston 38 Constant pressure chamber 40 Variable pressure chamber 51 Guide cylinder 55 Sleeve 56 Output rod 56A Large diameter portion 57 Elastic body 64 Push rod 70 Valve means 86 Reaction plate 157 Bamboo spring 257 Belleville spring 257a, 257b Cut 351A Recess 357A Rubber elastic body 359A Gap 356A Large diameter portion 451A Recess 457 Rubber elastic body

Claims (14)

[Claims] 1. A stepping force transmitting means 11 for transmitting a stepping force of a driver, and a stepping force transmission corresponding to a pressing force of the stepping force transmitting means 11 to brake generating means 2 and 3 in response to a pressing force of the stepping force transmitting means 11. Output means 12 for boosting and transmitting the pressing force of the means 11 and connecting a boosting means 13 and a valve means 14 to the output means 12; And a boosting force corresponding to the pressing force of the pedaling force transmitting means 11
In the brake booster 10 that closes the valve when the brake force occurs, the booster 13 includes a guide 15 that holds the pedaling force transmitting unit 11, and the booster 13 has a boost factor of the booster 13. A brake booster comprising a boost factor setting means 16 which can be adjusted in advance. 2. The boost factor setting means 16 includes a movement guide means 17 provided along a longitudinal direction of the guide means 15,
The tip end surface of the movement guide means 17 and the pedaling force transmission means 1
A reaction means 18 arranged between the end face of the first and the output means 12 and providing a reaction force to the pedaling force transmission means 11;
Limiting means 19 for limiting the amount of movement of the movement guiding means 17
And a resilient means 20 for generating a pressing force for the movement when the movement guide means 17 is moved by the reaction means 18 between the limiting means 19 and the movement guide means 17. The brake booster according to claim 1, wherein 3. A power piston 32 which partitions the interior of the housing 25 into a constant pressure chamber 38 connected to a negative pressure source and a constant pressure chamber 38 or a variable pressure chamber 40 connected to the atmosphere.
Is connected to a valve body 28 provided with a valve means 70, and an input rod 46 penetrating through the valve means 70 of the valve body 28 and connected to a push rod 64 is provided. An output rod 56 penetrating through the constant pressure chamber 38 is arranged.
In the brake booster in which a reaction plate 86 formed of an elastic body is arranged between the push rod 64 and the tip of the push rod 64, the push rod 64 is guided to the valve body 28 provided on the power piston 32. A guide cylinder 51 is provided, and a sleeve 55 guided by the guide cylinder 51 is provided at a position where the reaction plate 86 abuts.
6. A brake booster characterized in that, when pushed by a pushing force of 6, the amount of movement is limited by the valve body 28 and an elastic body 57 for giving a repulsive force in the direction of movement is inserted. 4. The power piston 3 of the output rod 56.
The brake booster according to claim 3, wherein an enlarged diameter portion (56A) is provided on two sides, and the enlarged diameter portion (56A) covers both the reaction plate (86) and the sleeve (55). 5. The brake booster according to claim 3, wherein the elastic body 57 that applies a pressing force to the sleeve 55 with which the reaction plate 86 contacts is an elastic body 57 made of metal. 6. The brake booster according to claim 5, wherein the metal elastic body 57 is a metal coil elastic body 57. 7. An elastic body 157 for applying a pressing force to a sleeve 155 abutting the reaction plate 186 is a metal bamboo child spring 157.
Brake booster as described. 8. The brake double according to claim 3, wherein the elastic body 257 for applying a pressing force to the sleeve 255 with which the reaction plate 286 contacts is a metal or non-metallic disc spring 257. Power device. 9. The brake booster according to claim 8, wherein cuts 257a and 257b are formed from inside or outside of the disc spring 257. 10. A power piston having a housing divided into a constant pressure chamber connected to a negative pressure source and a constant pressure chamber or a variable pressure chamber connected to the atmosphere, and a valve body provided with a valve device. An input rod that is connected to the push rod and penetrates the valve device of the valve body, and an output rod that penetrates the constant-pressure chamber concentrically facing the push rod and is disposed. And a guide plate 351 for guiding the push rod to a valve body provided on the power piston, in a brake booster including a reaction plate formed of an elastic body disposed between the piston and a tip of the push rod. On the reaction plate side of the guide cylinder 351, there is provided a concave portion 351A whose one side surface is open, and a sleeve 355 is provided on the open side surface of the concave portion 351A. This sleeve 3 is slidably arranged.
Elastic body 3 made of rubber between 55 and recess 351A
Reaction sleeve 355 with reaction plate 386
A brake booster characterized by being provided with a gap 359A that can move when is pressed. 11. A reaction plate 3 for the guide cylinder.
A concave portion 351A having one side surface opened on the side
11. A step portion having a single reaction plate 386 and two side surfaces opened to the outer periphery thereof, and the outer periphery of the step portion is covered with the enlarged diameter portion 356A of the output rod.
Brake booster as described. 12. The brake booster according to claim 10, wherein a concave portion 451A of which one side surface is opened on the reaction plate 486 side of the guide cylinder 451 is opened only in the reaction plate 486 of the guide cylinder 451. 13. The brake booster according to claim 10, wherein a sleeve 455 inserted into the recess 451A of the guide cylinder 451 and an elastic body 457 are bonded. 14. The brake booster according to claim 10, wherein the hardness of the reaction plate 486 is different from the hardness of the elastic body 457 disposed in the recess 451A.