JP2962333B2 - Brake booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake booster and, more particularly, to an improvement of a brake booster having a function as an automatic brake device.

[0002]

2. Description of the Related Art Conventionally, a brake booster having a function as an automatic brake device is known from Japanese Patent Application Laid-Open No. 60-25840. JP-A-60-2584
In the brake booster disclosed in Japanese Patent Publication No. 0, the transformer chamber of the front chamber and the transformer chamber of the rear chamber partitioned in the shell communicate with each other via a communication path formed of a conduit,
A switching valve is provided in the communication passage. When the brake booster functions as an automatic brake, the switching valve is switched to prevent communication between the two variable pressure chambers.
Atmosphere is introduced into the transformer room of the front room. In this way, by introducing the atmosphere into the variable pressure chamber of the front chamber, the brake booster can be operated without depressing the brake pedal. In addition, in addition to the above, as a brake booster having a function as an automatic brake device, JP-A-2-225166,
JP-A-1-127446 is also known.

[0003]

In the brake booster disclosed in Japanese Patent Application Laid-Open No. 60-25840, the constant pressure chamber of the front chamber is connected to the negative pressure chamber so that the brake booster can function as an automatic brake device. In addition to the negative pressure introducing pipe which constantly communicates with the pressure source, another conduit for communicating the two variable pressure chambers is provided as described above, and a switching valve is attached to the conduit. Therefore, when assembling the brake booster to the vehicle, the connecting operation of the plurality of conduits described above is required, so that there is a disadvantage that the assembling operation becomes complicated.

[0004]

[Means for Solving the Problems] In view of such circumstances,
The present invention provides a valve body slidably provided in a shell, a power piston connected to the valve body, a diaphragm stretched on the back of the power piston to partition the inside of the shell into a constant pressure chamber and a variable pressure chamber, and the valve A brake booster comprising: a valve mechanism formed in a body that communicates with the constant-pressure chamber and a valve mechanism that switches a fluid circuit; and a valve booster and a constant-pressure passage that communicates the constant-pressure chamber with the variable-pressure chamber through a variable-pressure passage. One end of a flexible conduit is connected to the constant pressure passage, and the other end is pulled out of the shell, and is connected to the outside of the shell.
A switching valve for selectively communicating the conduit with a negative pressure source or the atmosphere in the conduit located in the portion, and further, from a space inside the conduit to a constant pressure chamber located outside the conduit. A check valve is provided in the conduit in the constant-pressure chamber, the check valve being configured to allow the negative pressure to flow therethrough and to prevent the flow of the atmosphere from the space inside the conduit to the constant-pressure chamber located outside the conduit. It is a thing.

[0005]

According to such a configuration, only one conduit is required to connect the brake booster and the negative pressure source, so that the conventional brake booster requires a plurality of conduits.
The assembling work when assembling the brake booster to the vehicle is simplified. When a negative pressure is introduced into the conduit after the assembly is completed, the negative pressure introduced into the conduit is also introduced into the constant-pressure chamber via the check valve, and from that state, the brake is released. When the pedal is depressed, the brake booster is activated. On the other hand, when the air is introduced into the conduit by switching the switching valve, the air introduced into the conduit is prevented from being introduced into the constant-pressure chamber by the check valve. Therefore, at that time, the atmosphere introduced into the conduit is introduced into the variable pressure chamber through the valve mechanism and the variable pressure passage, whereby the brake booster can be operated even if the brake pedal is not depressed. Can be activated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a tandem brake booster will be described below. In FIG. 1, a shell 1 has a front shell 2 formed in a substantially cup shape,
And a substantially dish-shaped rear shell 3 for sealing the opening of the front shell 2. The cup-shaped front shell 2 has a small-diameter cylindrical portion 2A on the front side, a large-diameter cylindrical portion 2B on the rear side, and an annular wall portion 2C extending between the two in the radial direction. A larger-diameter cylindrical hooking portion 2D is formed on the opening side of the large-diameter cylindrical portion 2B. A center plate 4 formed in a substantially cup shape is fitted inside the front shell 2, and a front room 5 is defined between an end wall surface of the center plate 4 and an end wall surface of the front shell 2. Has formed. The center plate 4 is a large-diameter cylindrical portion 2 of the front shell 2.
B has a cylindrical portion 4A closely fitted therein, and the right end of the cylindrical portion 4A fitted to the large-diameter cylindrical portion 2B of the front shell 2 is a large-diameter cylindrical portion of the front shell 2. 2B
Is located slightly rearward from the end face of the step between the cylindrical hooking portion 2D. In this state, the flange 3A formed radially on the outer peripheral portion of the rear shell 3 is fitted to the cylindrical hook 2D of the front shell 2 and
The center plate 4 is in contact with the right end of the cylindrical portion 4A. The front shell 2, the center plate 4, and the rear shell 3 are integrally connected to each other by locking the rear shell 3 in this state with a plurality of engaging claws 2E formed on the cylindrical hooking portion 2D. ing. The flange portion 3 of the rear shell 3 connected as described above.
An O-ring 6 made of rubber is interposed between A and the step end surface of the front shell 2 opposed thereto, thereby maintaining airtightness between the two members. Further, the rear chamber 7 is formed between the wall surface of the rear shell 3 connected as described above and the end wall surface of the center plate 4.

A through hole is formed in each of the center shaft portions of the center plate 4 and the rear shell 3.
A stepped cylindrical valve body 8 is slidably penetrated into each of the through holes, and an airtightness between each through hole and the valve body 8 is maintained by a seal member 9. A front power piston 12 and a rear power piston 13 are provided in the front chamber 5 and the rear chamber 7, respectively.
And the inner periphery of each power piston 12, 13 is connected to the valve body 8, and the front diaphragm 1 is mounted on the rear side surface of each power piston 12, 13.
4 and a rear diaphragm 15 are respectively stretched, and inner peripheral portions of the respective diaphragms 14 and 15 are also connected to the valve body 8. On the other hand, the outer peripheral bead portions 14a, 15a of the respective diaphragms 14, 15 are sandwiched by the above-described front shell 2, center plate 4, and rear shell 3. That is, the outer peripheral bead portion 14a of the front diaphragm 14 is formed on the annular wall portion 2C of the front shell 2 and the opposed wall portion formed on the outer peripheral portion of the left end of the cylindrical portion 4A of the center plate 4 so as to face the annular wall portion 2C. 4
B and B. In this manner, the airtightness of the front chamber 5 is divided into a constant-pressure chamber A on the front side and a variable-pressure chamber B on the rear side. At this time, the radially inner portion of the opposed wall portion 4B is annularly protruded toward the annular wall portion 2C, so that airtightness can be maintained more reliably. An outer peripheral bead portion 15a of the rear diaphragm 15 is housed in an annular groove 3B formed radially outward on the outer peripheral portion of the rear shell 3, and the outer peripheral bead portion 15a
The outer peripheral surface of the annular groove 3B and the cylindrical portion 4 of the center plate 4
A is sandwiched in the radial direction by the inner peripheral surface of A, thereby maintaining the airtightness of that portion, and the inside of the rear chamber 7 is divided into a constant pressure chamber C on the front side and a variable pressure chamber D on the rear side. A valve mechanism 16 having a conventionally well-known configuration is provided in the valve body 8.
In a state where the pressure chamber 8 is not provided, the fluid circuit between the two constant pressure chambers A and C and the two variable pressure chambers B and D can be switched by the valve mechanism 16.

The valve mechanism 16 includes an annular first valve seat 17 formed in the valve body 8 and a right end of a valve plunger 18 slidably provided on the valve body 8 inside the annular first valve seat 17. Annular second valve seat 19 formed in the section
1 and the springs 20 from the right side of FIG.
And a valve body 21 to be seated. The first
In the state where the bellows 38 is not provided, the space on the outer peripheral side of the annular seat portion where the valve seat 17 and the valve body 21 are in contact with each other is the first constant pressure passage 2 formed in the valve body 8 in the axial direction.
4 communicates with the constant pressure chamber A. In the constant pressure chamber A, a negative pressure is introduced from a negative pressure source via a negative pressure introducing pipe 25 having one end penetrating the front shell 2.
The constant-pressure chamber A is provided with an annular wall 2C of the front shell 2.
Is constantly communicated with a constant pressure chamber C via a second constant pressure passage 26 described later. Therefore, when a negative pressure is introduced into the constant pressure chamber A, the negative pressure is also introduced into the constant pressure chamber C via the second constant pressure passage 26. On the other hand, on the inner peripheral side of the annular seat portion where the first valve seat 17 and the valve body 21 are in contact, and on the outer peripheral side of the annular seat portion where the second valve seat 19 and the valve body 21 are in contact, That is, the space in the middle portion between the inner and outer annular seat portions is communicated with the variable pressure chamber D through the radial variable pressure passage 27 formed in the valve body 8, and the variable pressure chamber D is formed in the other axial direction formed in the valve body 8. It is communicated with the variable pressure chamber B via the variable pressure passage 28. Further, the space on the inner peripheral side of the inner annular seat portion where the second valve seat 19 and the valve element 21 are in contact with each other is the filter 2.
9 and communicate with the atmosphere. The right end of the valve plunger 18 slidably provided on the valve body 8 is connected to an input shaft 30 linked to a brake pedal (not shown).
And the left end thereof is opposed to the right end surface of the reaction disk 32 housed in the concave portion 31a formed at the base of the push rod 31. The left end of the push rod 31 is linked to a piston of a master cylinder (not shown) through an opening 2a of a shaft in the front shell 2. Airtightness is maintained between the opening 2a and the push rod 31 by a seal member 33. Since the return spring 34 is mounted between the valve body 8 and the front shell 2,
The valve body 8 is normally held at a non-operating position shown. In this non-operating state, the valve body 21 is in the second valve seat 1.
9, a slight gap is maintained between the first valve seat 17 and the valve element 21.

In this embodiment, however, the front shell 2
A rubber bellows 38 is attached to the reinforcing plate 37 attached to the inner wall of the valve body 8 and the outer periphery of the front end of the valve body 8, and one end is connected to the reinforcing plate 37 through the front shell 2 and the reinforcing plate 37. Negative pressure introduction pipe 2
5, the internal space A 'of the bellows 38 communicates with the negative pressure source. That is, the rear end of the thickened bellows 38 is pressed into the annular recess 12 a formed in the inner periphery of the front power piston 12 and then fitted to the outer periphery of the valve body 8 from the front side. Retainer 3
9 locks in the annular recess 12a so that the rear end of the bellows 38 and the annular recess 1
2a is kept airtight. On the other hand, bellows 38
Is folded back in a U-shape toward the inward side, and fits into the outer peripheral tubular portion 37a of the reinforcing plate 37 with the outer peripheral edge of the second retainer 40 sandwiched between the folded portions. Like that. Thereby, airtightness between the outer peripheral cylindrical portion 37a of the reinforcing plate 37 and the front end of the bellows 38 is maintained. The inner peripheral portion of the second retainer 40 is fitted on the shaft portion of the front shell 2, and the airtightness between the shaft portion of the front shell 2 and the reinforcing plate 37 is maintained by a rubber O-ring 41. . In the middle of the negative pressure introducing pipe 25, a solenoid valve 42 for selectively communicating the negative pressure introducing pipe 25 with the atmosphere and a negative pressure source is provided. The solenoid valve 42 is ON / OFF controlled by a controller (not shown), and connects the negative pressure introducing pipe 25 to the negative pressure source in a normal state where it is not operated. Therefore, at that time, the negative pressure introduction pipe 25
, A negative pressure is introduced into the internal space A ′ of the bellows 38. On the other hand, when the solenoid valve 42 is operated by the controller when necessary, the negative pressure introduction pipe 25
The atmosphere is introduced into the internal space A ′ of the bellows 38 through the air.

Further, in the present embodiment, the bellows 3 described above is used.
8, a check valve 43 made of rubber is provided. The check valve 43 allows a negative pressure to flow from the internal space A 'of the bellows 38 to the constant-pressure chamber A, and the internal space A of the bellows 38. ′, The introduction of air to the constant pressure chamber A is prevented. The check valve 43 is formed in a substantially funnel shape, and its constricted tip portion is located in the internal space A 'of the bellows 38, while the enlarged outer peripheral portion serving as the other end is formed in the bellows 38. It fits into the through hole with keeping airtightness. The check valve 43 attached to the bellows 38 in this manner normally normally completely closes its distal end by its own elasticity. Therefore, when a negative pressure is introduced into the internal space A ′ of the bellows 38 via the negative pressure introducing pipe 25, the bellows 38
The check valve 4 by the negative pressure introduced into the internal space A '
Since the distal end portion 3 is expanded, a negative pressure is introduced from the internal space A ′ of the bellows 38 to the constant pressure chamber A via the check valve 43. At that time, a negative pressure is also introduced into the constant pressure chamber C of the rear chamber via the second constant pressure passage 26.
Conversely, when the controller activates the solenoid valve 42 as required and air is introduced into the internal space A 'of the bellows 38, the atmospheric pressure introduced into the internal space A' of the bellows 38 is reduced by the atmospheric pressure. Because of the elasticity of the check valve 43 itself, the distal end of the check valve 43 is closed, so that communication between the internal space A ′ of the bellows 38 and the constant pressure chamber A is prevented. Therefore, the air introduced into the internal space A ′ of the bellows 38 is introduced into both the variable pressure chambers B and D via the first constant pressure passage 24, the variable pressure passage 27, and the variable pressure passage 28. As described above, in the present embodiment, by operating the solenoid valve 42 from the inoperative state of the tandem brake booster shown in FIG. 1, even if the brake pedal (not shown) linked to the input shaft 30 is not depressed. The tandem brake booster can be operated. Further, in the present embodiment, the second constant pressure passage 26 that connects the two constant pressure chambers A and C is configured as follows. That is, the second
The constant pressure passage 26 is formed in the annular wall 2C of the front shell 2 described above.
An inner peripheral surface and an outer peripheral bead of the large-diameter cylindrical portion 2B of the front shell 2 at a position radially outward of a portion sandwiched between the outer peripheral bead portion 14a of the front diaphragm 14 and the opposing wall portion 4B of the center plate 4. A first passage 44 formed between the outer peripheral surface of the portion 14a and the axially rear end of the first passage 44 at the center plate 4 at a position radially outward of the holding portion. It communicates with the constant-pressure chamber C of the rear chamber through the perforated through-hole 4C. On the other hand, the end of the first passage 44 on the axial front side is formed by swelling a part of the small-diameter cylindrical part 2A and a part of the annular wall part 2C of the front shell 2 radially outward. Through the second passage 45 in the bulging portion 2F, it communicates with the constant pressure chamber A in the front chamber. Therefore, in the present embodiment, the two constant-pressure chambers A and C are in direct communication with each other via the second constant-pressure passage 26, and when a negative pressure is introduced into the constant-pressure chamber A in the front chamber, the constant-pressure chamber C in the rear chamber. Negative pressure is introduced inside.

As described above, in the present embodiment, since the check valve 43 is provided on the bellows 38, a conduit for connecting the negative pressure source and the tandem brake booster is provided.
It is only necessary to provide one negative pressure introducing pipe 25. Therefore, when assembling the tandem brake booster configured as described above to a vehicle, it is only necessary to connect the single negative pressure introduction pipe 25 to a negative pressure source, so that a plurality of conduits are provided. The assembling work is simplified as compared with the related art. In other words, the bellows 3 can be formed simply by disposing the bellows 38.
In the case where the check valve 43 is not provided in the apparatus 8, another negative pressure introducing pipe for directly communicating the constant pressure chamber A with the negative pressure source is required separately from the negative pressure introducing pipe 25. become,
As a result, two negative pressure introducing pipes must be provided. In the case of such a configuration requiring two negative pressure introduction pipes,
When assembling the tandem brake booster to the vehicle, the operation becomes complicated. Further, in the tandem brake booster assembled to the vehicle as described above, the solenoid valve 42 is not normally operated as shown in FIG. Since the negative pressure is introduced into the inside of the chamber A, the tip of the check valve 43 is expanded, so that the negative pressure is introduced into all the chambers A, B, C, D and A '. . When a brake pedal (not shown) is depressed from this non-operating state, the input shaft 30 moves forward (leftward), and accordingly, the fluid circuit is switched by the valve mechanism 16, and the atmosphere is introduced into both the variable pressure chambers B and D. You. As a result, an output having a predetermined servo ratio can be obtained from the push rod 31 in the same manner as in a conventionally known tandem brake booster. When the tandem brake booster functions as an automatic brake device with respect to the normal brake operation,
The solenoid valve 42 may be operated by the controller from the inoperative state where the input shaft 30 shown in FIG. 1 is not advanced. As a result, the air is introduced into the internal space A 'of the bellows 38, but the air introduced into the internal space A' of the bellows 38 is prevented from being introduced into the constant pressure chamber A by the check valve 43. Therefore, the first constant pressure passage 24
And the variable pressure passage 27 and the variable pressure passage 2 in communication therewith
8 into both transformer chambers B, D. As a result, a pressure difference is generated between the two constant pressure chambers A and C and the two variable pressure chambers B and D, so that a predetermined output can be obtained from the push rod 31 even when the brake pedal is not depressed.

In this embodiment, when the tandem brake booster functions as an automatic brake device, the atmosphere can be introduced into both the transformation chambers B and D. Therefore, according to the present embodiment, when the tandem brake booster is operated as an automatic brake device, as compared with a conventional device in which the atmosphere is introduced into only one of the transformer chambers to function as an automatic brake device, The output of the tandem brake booster can be increased. Further, in this embodiment, since the second constant pressure passage 26 is provided on the outer side of the outer peripheral bead portion 14a of the front diaphragm 14 instead of being provided on the valve body 8, an axial hole formed on the valve body 8 and According to the present embodiment, it is possible to increase the strength of the valve body 8 in comparison with the conventional device in which the second constant pressure passage 26 is constituted by the radial holes continuously opening on the outer peripheral surface of the valve body 8. it can. In addition, by configuring the second constant pressure passage 26 as described above, when the tandem brake booster functions as an automatic brake, the output can be further increased as compared with the related art. That is, the axial hole and the radial hole for forming the second constant pressure passage 26 are formed in the valve body 8.
, It is possible to reduce the radial dimension of the valve body 8 as compared with such a conventional valve body 8. Thereby, the effective area of both diaphragms 14 and 15 connected to valve body 8 can be increased. Therefore, also in this sense, when the tandem brake booster is caused to function as an automatic brake, the output can be increased as compared with the conventional case.

FIG. 2 shows a second embodiment of the check valve 43. The check valve 143 of this second embodiment is shown in FIG.
Then, the annular concave portion 112 of the front power piston 112
A plurality of linear notches 138a are formed in the surface of the rear end portion of the bellows 138 that abuts on the a in the radial direction of the annular concave portion 112a. In addition, the notch 1
Bellows 138 located radially inward from 38a
The inner peripheral edge 138b is formed in a lip shape, and the front end of the inner peripheral edge 138b is brought into close contact with the cylindrical portion that becomes the inner peripheral edge of the annular concave portion 112a. Also, a plurality of notches 139a are formed on the inner peripheral edge of the retainer 139 in which the rear end of the bellows 138 is locked in the recess 112a, and the retainer 139 is formed through the notches 139a.
The space before and after is connected. According to the check valve 143 of the second embodiment, when air is introduced into the internal space A 'of the bellows 138, the lip-shaped inner peripheral edge 138b of the bellows 138 is formed as shown in FIG. The pressure contact with the inner peripheral edge of the annular concave portion 112a of the front power piston 112 prevents the introduction of the atmosphere into the constant pressure chamber A. On the other hand, when a negative pressure is introduced into the internal space A 'of the bellows 138, as shown in FIG.
The negative pressure introduced into the internal space A ′ of the bellows 138 is introduced into the constant-pressure chamber A through the notch 138 a of the bellows 138 because it is separated from the inner peripheral edge of the twelve concave portions 112 a. Even with such a check valve 143 of the second embodiment,
The same operation and effect as those of the check valve 43 of the first embodiment can be obtained. In the second embodiment, each member corresponding to the first embodiment is given a member number obtained by adding 100. Further, in the first embodiment, the second constant-pressure passage 26 is configured as described above. Instead of such a configuration, the two constant-pressure chambers A and C are directly communicated with each other by a conduit, and the inside of the conduit is formed. The space may be the second constant pressure passage 26. In the above embodiments, the present invention is applied to a tandem brake booster. However, the present invention can be applied to a single type brake booster.

[0014]

As described above, according to the present invention, when assembling a brake booster having a function as an automatic brake device to a vehicle, the assembling work can be simplified as compared with the conventional art. The effect that it can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the main part of FIG. 1;

FIG. 3 is a sectional view showing a different state of FIG. 2;

[Explanation of symbols]

 8 Valve body 25 Negative pressure introducing pipe 38 Bellows 42 Solenoid valve 43 Check valve 138 Bellows 143 Check valve A, C Constant pressure chamber A 'Inner space of bellows 38, 138 B, D Transformer chamber

Claims (5)

(57) [Claims] 1. A valve body slidably provided in a shell, a power piston connected to the valve body, a diaphragm stretched on the back of the power piston to partition the inside of the shell into a constant pressure chamber and a variable pressure chamber, A brake booster comprising: a valve mechanism formed in a valve body for communicating with the constant pressure chamber and a valve mechanism for switching a fluid circuit; and a constant pressure passage that communicates the valve mechanism with the constant pressure chamber via the variable pressure passage. Connecting one end of the flexible conduit to the constant pressure passage, pulling the other end out of the shell, and positioning it outside the shell.
Conduit switching valve for selectively communicating the conduit to a negative pressure source or the atmosphere is arranged in the further, negative pressure from the space inner side of the conduit to the pressure chamber located on the outer side of the conduit allows distribution, and a check valve for preventing flow of air from the space inner side of the conduit to the pressure chamber located on the outer side of the conduit, said constant pressure chamber
A brake booster provided in a conduit inside . 2. A conduit located in the constant pressure chamber, wherein the conduit is located in an axial direction.
This bellows is made of bellows that can be expanded and contracted.
End of the shell to the shell wall and
The rear end of the door is connected to the constant pressure passage, Further, the check valve is provided on the bellows.
The brake booster according to claim 1, wherein: 3. The check valve according to claim 1, wherein the check valve is provided at an axial position of the bellows.
Mounted in place and tip protrudes into bellows
3. The method according to claim 2, wherein the elastic member has a conical shape.
On-board brake booster. 4. The valve according to claim 1, further comprising:
To form a cylindrical part to be fitted to the outer periphery of the bubody
Attach the rear end of the bellows to the power
And connect the check valve to the power piston.
Connection of the ton's tubular part with the rear end of the bellows
3. The breaker according to claim 2, wherein the breaker is provided on a portion.
Ki booster. 5. An inner peripheral portion at a rear end of the bellows.
A lip is formed, and the lip and the power piston are
It is characteristic that the above check valve is composed of a cylindrical part. To collect
The brake booster according to claim 4.