JP3171820B2 - Brake booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a master cylinder which is disposed between a brake pedal to which a driver's pedaling force is applied and a master cylinder which converts the pedaling force into hydraulic pressure, and which increases the pedaling force applied 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.
Output means 12 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 braking force generating means in accordance with the pressing force of the treading force transmitting means 11
And the output means 12 has a booster 13
And the valve means 14, which is opened by the pedaling force transmitting means 11,
3 is a brake booster 10 that closes when a boost corresponding to the pressing force of the treading force transmitting means 11 is generated, wherein the boosting means 13 comprises a guiding means 15 for supporting the treading force transmitting means 11. the provided, boosting factor setting means can precondition the boosting ratio of the booster means 13 to the guide means 15 16
In the brake booster 10 having the above, the boost factor setting means 16 includes a movement guide means 17 provided along the longitudinal direction of the guide means 15, a tip surface of the movement guide means 17 , Tip surface and pedal force transmitting means 1
1 of the reaction means providing end face and a reaction force to the pedal force transmission means 11 Yes disposed between said output means 12 18
When, the mobile guide means 1 by the end plane of the axial direction of said moving guide means 17 abuts directly the guide means 15
And a resilient means for generating a pressing force for the movement when the movement guide means is moved toward the limit means by the reaction means. Composed and before
From the output means 12 to the reaction means 18
Based on the increase in the reaction force, the
The contact area of the end face with the reaction means 18 is reduced by one.
While maintaining the constant, the reaction means 1
8 shows the reaction force transmission area from the booster 13 to the booster 13
Movement by the limiting means 19 to the front end face of the means 15
A surface to which the tip surface of the restricted movement guide means 17 is added
It is characterized by increasing the product .

According to a second aspect of the present invention for solving the above-mentioned problems, 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 power piston 32 is connected to the valve body 28 having the valve device 60, and the input rod 46 is provided through the valve device 60 and connected to the push rod 64. The input rod 46 is concentrically opposed to the push rod 64. An output rod 56 penetrating the constant pressure chamber 38 is arranged,
In 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, the push rod 64 is guided to the valve body 28 on the inner peripheral side. the guide cylinder 51 is provided, the tip of the sleeve 55 to be more guided on the outer periphery of the guide cylinder 51, its front end surface of the abutment guide tube to
Able to contact the reaction plate 86 with the surface
The reaction play of the sleeve 55
The amount of movement in the direction away from preparative 86 while restricted by the valve body 28, before the sleeve 55
Elastic body 5 pressed against reaction plate 86
7, made by interposing between the sleeve 55 and the valve body 28, with the advancement of the input rod 46
From the output rod 56 to the reaction plate 8
6 based on the increase in the reaction force applied to
For the reaction plate 86 at the tip of the rod 64
While keeping the contact area constant,
From the action plate 86 to the valve body 28
The reaction force transmission area is defined by the area of the tip of the guide cylinder 51 and the
Sleeve 55 whose movement is restricted by the lube body 28
Is increased to an area that is the sum of the area of the tip end surface and the area .

The power piston 32 of the output rod 56
It is preferable that the 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 3). 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 coil spring .

According to a fifth aspect of the present invention which solves the above problems, the housing 28 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 power piston 32, connecting the valve body over 28 with a valve device 60, the input rod 46 to the push rod 64 through the valve device 60 of this is articulated provided, facing the push rod 64 coaxial with A brake booster comprising an output rod 56 penetrating through the constant pressure chamber, 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 valve body
-28 , a guide cylinder 35 for guiding the push rod 64
The reaction plate 3 of the guide cylinder 351 is provided.
86 side a recess 351A in which one side is open, while being disposed a sleeve 355 slidably to the reaction plate 386 side surface of the concave portion 351A, the
In the space of the sleeve 355 and the concave portion 351A, the sleeve 35 is provided.
5 is the pressing force from the reaction plate 386,
A gap 359A allowing the movement to the concave portion 351A side is formed.
An elastic body 357A made of rubber is arranged,
The movement of the sleeve 355 is restricted by the elastic body 357A.
It is characterized by doing .

[0011]

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 is a brake booster.
A pedal force transmission means (pushrod) 11 that operates in accordance with the movement of the dull, for the braking force generating means 2, 3 receives the pressing force of the treading force transmission means 11, the more booster means 13
Output means (output rod) for transmitting the boosted force
12 and the pedaling force transmitting means 11 to open the valve.
The valve means 14, which is closed by boosting the pressing force of the transmission means 11, and the boosting means 13,
With a guide means 15 for supporting the 1, but provided with 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 face of the moving guide means 17 and the pedaling force transmitting means 11.
End surface and the reaction means 18 to provide a reaction force to the pedal force transmission means 11 Yes disposed between the output section 12, the axial direction of the one side end face directly guiding means 1 of the moving guide means 17
5 for limiting the amount of movement of the movement guide means 17 by contacting the movement guide means 5; and when the movement guide means 17 is moved by the reaction means 18 between the limitation means 19 and the movement guide means 17; And a resilient means 20 for generating a pressing force for the movement.

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 a shaft core portion, and a peripheral portion of the hole is integrated with the valve body 28 by being engaged with a main body portion 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.

An input rod 46 is disposed in the cylindrical portion 28C of the valve body 28 described above. The rear end of the input 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 input rod 46 moves axially toward the front of the vehicle. A silencer / air filter assembly 52 is disposed between the axial middle portion of the input rod 46 and the rear end of the cylindrical portion 28C. Further, a valve device 6 to be described later is provided on the distal end side of the input 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 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 above-described 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 configuration related thereto will be described in detail with reference to FIG.

The reaction plate 86 has a disk shape with a predetermined outer dimension a, and is fitted in a concave portion 56C having a predetermined inner diameter dimension 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.
In addition to having a function of obtaining a predetermined boost factor by dispersing and transmitting the reaction force from the side of FIG. 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
And the sleeve 55 is pushed backward by overcoming the urging force of the elastic body 57, and the distance 55 becomes zero when the sleeve 55 hits the regulating surface 52.

Next, the operation of the present 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.

[0032] slightly 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, input
Since the force rod 46 is pressed to the left in the drawing against the urging force of the return spring 76, the front end face of the pressing portion 64 </ b> C of the push rod 64 abuts 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 input rod 46 is further pushed to the left in the drawing, 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, the pedaling force applied to the brake pedal 1 is transmitted from the input rod 46 to the reaction plate 86 via both the push rod 64 and the power piston 32, and further transmitted 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
The area B of the outer diameter b 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 the present embodiment is a line graph having 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, the sleeve 55 and the 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 where 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 where 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 486 side at the tip end surface of the guide cylinder 451.
And the rubber elastic body 457 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 486 and the sleeve 455 is preferably a child so does not change the posture against the rubber elastic body 457 of the sleeve 455. Further, by varying the phase and the rubber hardness of the rubber hardness and rubber elastic body 457 of the reaction plate 486, the elastic modulus of a rubber elastic body 457 can be changed (the spring constant).

[0043]

According to the first aspect of the present invention, the guide means 15 is provided.
Is provided with a movement guide means 17 and a resilient means 20. Since 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, the resilient means 20 is provided. The point at which the boost factor changes can be changed by changing the pressing force, and the point at which the boost factor changes can be obtained by using the elastic means 20 having various linear or non-linear spring constants. Can be changed, so that a predetermined boosting characteristic matching various braking characteristics can be obtained.

According to the second to fourth aspects of the present invention, the sleeve 55 and the elastic body 57 for obtaining the breaking 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 fifth aspect of the present invention, since a rubber elastic body such as a synthetic rubber is used, by changing the cross section of the rubber elastic body to provide various gaps, the elastic modulus can be selected in various forms nonlinearly. . 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 (braking force generating means) 3 Brake device (braking force 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 Movement guide means 18 Reaction means 19 Restriction means 20 resiliently means 26 housing 28 the valve body over 32 power piston 38 pressure chamber 40 variable pressure chamber 51 the guide tube 55 sleeve 56 output rod 56A enlarged diameter portion 57 elastic member 64 push rod 70 valve means 86 the reaction plate 157 volute spring 257 disc spring 257a, 257b Cut 351A Recess 357A Rubber elastic body 359A Gap 356A Large diameter portion 451A Recess 457 Rubber elastic body

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-92242 (JP, A) JP-A-8-85442 (JP, A) JP-A-5-178203 (JP, A) 205858 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 13/573

Claims (5)

(57) [Claims] 1. Tread force transmitting means 1 for transmitting a tread force of a driver
Output means 12 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 braking force generating means in accordance with the pressing force of the treading force transmitting means 11
And the output means 12 has a booster 13
And the valve means 14, which is opened by the pedaling force transmitting means 11,
3. A brake booster 10 that closes when a boost corresponding to the pressing force of the treading force transmitting means 11 is generated by the booster 3. The boosting means 13 includes a guiding means 15 for supporting the treading force transmitting means 11. the provided, in the brake booster 10 having a booster ratio setting means 16 which can be pre-adjusted boosting ratio of the booster means 13 to the guide means 15, the boosting ratio setting unit 16 of the guide means 15 a moving guide means 17 provided along the longitudinal direction, the distal end surface of the moving guide means 17, there are arranged between the end face and the output means 12 of the distal end surface and the treading force transmission means 11 of the guide means 15 and reaction means 18 to provide a reaction force to the pedal force transmission means 11, the moving amount of the moving guide means 17 by the end <br/> plane of the axial contact directly the guide means 15 of the mobile guide means 17 Control And limiting means 19 for limited, when said moving guide means 17 are approximated moved toward said restriction means 19 by the reaction unit 18 is constituted by a resilient means 20 for generating the pushing force for the movement, said output Means from the means 12
As the reaction force applied to the step 18 increases, the pedaling force
The end face of the transmission means 11 is opposed to the reaction means 18.
While keeping the contact area constant,
Reaction force transmission surface from the traction means 18 to the booster 13
The product is added to the front end surface of the guiding means 15 by the limiting means 1.
9. The tip of the movement guide means 17 whose movement is restricted by 9.
Brake booster characterized by increasing the area to the area added . 2. A power piston 32 which divides a 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 to form respective power pistons 32.
Is connected to the valve body 28 having the valve device 60,
An input rod 46 penetrating the valve device 60 and connected to a push rod 64 is provided, and an output rod 5 penetrating through the constant pressure chamber 38 concentrically facing the push rod 64.
6. A brake booster comprising a reaction plate 86 formed of an elastic body disposed between the output rod 56 and the tip of the push rod 64. 64 in
The guide tube 51 which guides the circumferential side provided outside the guide cylinder 51
A sleeve 55 which is more guided circumferentially, its front end surface abutment
The reaction plate 86 together with the front end surface of the guide cylinder
And the sleeve 55
The amount of movement in the direction away from the Deployment plate 86 as well as restricted by the valve body 28, the ground
Pressure on the reaction plate 86
The input rod 46 is formed by interposing an elastic body 57 between the sleeve 55 and the valve body 28.
The output rod 56 moves the reaction
Based on the increase in the reaction force applied to the plate 86,
The reaction play at the tip of the push rod 64
While keeping the contact area to
Then, the valve body is removed from the reaction plate 86.
The area for transmitting the reaction force to the wire 28
Product and movement restricted by the valve body 28
The area increased to the sum of the area of the tip surface of the sleeve 55
A brake booster characterized in that 3. The power piston 3 of the output rod 56.
The brake booster according to claim 2, wherein an enlarged diameter portion (56A) is provided on the second side, and the enlarged diameter portion (56A) covers both the reaction plate (86) and the sleeve (55). 4. The elastic body 57 that applies a pressing force to the sleeve 55 with which the reaction plate 86 contacts,
The brake booster according to claim 2 or 3, wherein the coil booster is a metal coil spring. 5. A power piston 32 which is divided into a constant pressure chamber 38 for connecting the housing 25 to a negative pressure source and a constant pressure chamber 38 or a variable pressure chamber 40 connected to the atmosphere.
Is connected to the valve body 28 having the valve device 60,
An input rod 46 penetrating the valve device 60 and connected to a push rod 64 is provided, and an output rod 5 penetrating through the constant pressure chamber 38 concentrically facing the push rod 64.
6. A brake booster comprising a reaction plate 86 formed of an elastic body disposed between the output rod 56 and the tip of the push rod 64. 64 is provided on the reaction plate 386 side of the guide cylinder 351.
A is provided, and a sleeve 355 is slidably disposed on the side surface of the recess 351A on the side of the reaction plate 386, and the sleeve 355 is pressed by the pressing force from the reaction plate 386 in the space between the sleeve 355 and the recess 351A. Elastic body 3 made of rubber and having gap 359A allowing movement to concave side 351A side
57A, and the sleeve 3
55. A brake booster characterized by restricting the movement of 55.