JP4848596B2 - Negative pressure booster - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a negative pressure booster for a vehicle.
[0002]
[Prior art]
Usually, in a negative pressure type booster, a housing that forms at least one pressure chamber inside, a housing that can be moved forward and backward with respect to the housing, and that the pressure chamber is divided into a constant pressure chamber and a variable pressure chamber. A movable wall to be divided, a power piston coupled to the movable wall, an input member installed inside the power piston so as to be able to move forward and backward, and a propulsive force of the power piston accompanying the movement of the movable wall An output member that outputs to the outside of the apparatus, a biasing member that is provided in the housing and biases the power piston toward the rear, a first end is pressed against the power piston by the biasing member, and a second end is A rod retainer for restricting the separation of the output member from the power piston is provided. An example of such a conventional negative pressure booster is described in Japanese Patent Application Laid-Open No. 8-67239.
[0003]
In this system, the air is introduced into the variable pressure chamber in accordance with the brake operation, the power piston coupled to the movable wall and the movable wall moves forward, and the propulsive force of the power piston is output to the external device such as the master cylinder by the output member. , Braking force is generated. When the brake operation is completed, the output member and the power piston are returned backward by the reaction force from the external device such as the master cylinder. At this time, the output member inserted into the front end of the power piston is the power piston. A rod retainer is provided so as not to fall off. In the rod retainer, the first end is pressed against the power piston by the biasing member, and the second end restricts the detachment of the output member from the power piston.
[0004]
[Problems to be solved by the invention]
However, in this conventional negative pressure type booster, when the power piston makes a full stroke forward, the second end of the rod retainer is sandwiched between the front end surface of the power piston and the inward protruding part of the front of the housing, There is a possibility that the second end of the rod retainer may be deformed or damaged.
[0005]
The present invention is a negative pressure type in which the second end portion of the rod retainer is not deformed or damaged even when the power piston makes a full stroke forward, and the detachment of the output member from the power piston can be reliably regulated. An object is to provide a booster.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, as described in claim 1, a housing that forms at least one pressure chamber therein, a housing that can be moved forward and backward with respect to the housing, and A movable wall that divides the pressure chamber into a constant pressure chamber and a variable pressure chamber; a power piston coupled to the movable wall; and an input member installed inside the power piston so as to be capable of moving forward and backward with respect to the power piston. An output member that outputs the propulsive force of the power piston that accompanies the movement of the movable wall to the outside of the device, a first end that contacts the power piston, and a second that restricts the separation of the output member from the power piston. And a rod retainer provided with an end.When the power piston makes a full stroke forward, the front end surface of the power piston comes into contact with the inward protruding portion in front of the housing.In the negative pressure type booster, the front end surface of the second end portion of the rod retainer is located behind the front end surface of the power piston.And the second end of the rod retainer includes a plurality of tongues extending radially inward, and the tongues engage with a plurality of grooves provided in a circumferential direction on the front end surface of the power piston. DoThe negative pressure type booster characterized by this was constructed.According to a second aspect of the present invention, the housing forms at least one pressure chamber therein, and is installed in the housing so as to be capable of moving forward and backward relative to the housing, and the pressure chamber is a constant pressure chamber. A movable wall that is divided into a variable pressure chamber, a power piston that is coupled to the movable wall, an input member that is installed inside the power piston so as to be capable of moving forward and backward, and movement of the movable wall An output member that outputs the propulsive force of the power piston to the outside of the apparatus, a first end that contacts the power piston, and a second end that restricts the separation of the output member from the power piston. A rod retainer, and when the power piston makes a full stroke forward, a front end surface of the power piston and an inward projecting portion in front of the housing In the negative pressure type booster that abuts, the front end surface of the second end portion of the rod retainer is behind the front end surface of the power piston, and the second end portion of the rod retainer extends radially inward. The rim portion includes a plurality of tongue-shaped rim portions and a ring portion that connects the rim portions in the circumferential direction, and the rim portion engages with a plurality of grooves provided in the circumferential direction on the front end surface of the power piston. The negative pressure type booster characterized by this was constructed.
[0007]
The rear means the brake pedal side or the vehicle rear side with respect to the negative pressure booster, and the front means the master cylinder side or the vehicle front side with respect to the negative pressure booster.
[0008]
Claim 1, Claim 2According to the invention, the front end surface of the second end of the rod retainer is disposed rearward of the front end surface of the power piston, so that the front end surface of the power piston and the housing can be used even during a full stroke forward of the power piston. The second end portion of the rod retainer is not sandwiched between the front projecting portion and the second end portion of the rod retainer, and the second end portion of the rod retainer is reliably prevented from being deformed or damaged.
[0010]
Also,Claim1According to the invention, since the second end portion of the rod retainer is formed as a plurality of tongue pieces, it is possible to obtain an appropriate elastic force for pressing the output member against the power piston, and at the time of press molding of the rod retainer. A tongue piece is easily formed. Further, since the tongue piece is engaged with a plurality of grooves provided in the circumferential direction on the front end face of the power piston, the rod retainer can be easily and reliably assembled.
[0012]
Also,Claim2According to the invention, since the second end portion of the rod retainer is formed from a plurality of tongue-shaped rim portions extending radially inward, an appropriate elastic force can be obtained, and the rim portion and the ring portion Are integrally formed, and thus have high strength. In addition, since the rim portion is engaged with a plurality of grooves provided in the circumferential direction on the front end surface of the power piston, the rod retainer can be easily and reliably assembled.
[0013]
Next, the claim3The negative pressure type booster is characterized in that the second end of the rod retainer presses the output member elastically toward the power piston as shown in FIG.
[0014]
Claim3According to the invention, the second end portion of the rod retainer elastically presses the output member against the power piston, so that the detachment of the output member from the power piston can be reliably regulated.
[0015]
Next, the claim4And a negative pressure valve seat disposed on the power piston and facing backward, and a reaction force member that transmits a reaction force according to the output of the output member to the input member, and A valve mechanism having a movable part facing the negative pressure valve seat and a fixed part fixed to the power piston in an airtight manner, the negative pressure valve seat comprising: a first negative pressure valve seat integrated with the power piston; The first negative pressure valve seat can be moved forward and backward with respect to the power piston, and a second negative pressure valve seat provided on a substantially concentric valve seat member, and the advance amount of the input member relative to the power piston is less than a predetermined value In this case, holding means for holding the valve seat member in a predetermined position forward, and when the advance amount of the input member relative to the power piston is larger than a predetermined value, the valve seat member is moved backward by a predetermined amount. And stage, the power piston vacuum booster is preferably characterized in that a return means for returning the valve seat member to a predetermined forward position when a predetermined position relative to the housing.
[0016]
Claim4According to the invention, when the relative movement amount between the input member and the power piston is equal to or greater than a predetermined value, that is, during emergency braking in which the driver rushes and depresses the brake pedal, the holding of the valve seat member by the holding means is released, The valve seat member is moved backward by a predetermined amount by the movable means, and the second negative pressure valve seat provided on the valve seat member presses the movable portion of the valve mechanism rearward, so that the variable pressure chamber is rapidly and forcibly released into the atmosphere. Communicated with.
[0017]
As a result, a propulsive force larger than that during normal braking is applied to the movable wall, the power piston, and thus the output member, and a sufficiently large brake fluid pressure can be generated. In other words, jumping characteristics (the ratio of output to input is infinite until the input member comes into contact with the reaction member when the brake pedal is depressed and brake operation is performed, which is called jumping) Thus, a larger propulsive force than that during normal braking is applied to the output member. That is, a negative pressure booster having two types of input-output characteristics, that is, a normal brake characteristic and an emergency brake characteristic, that is, a negative pressure booster with a B / A (brake assist) function can be realized with a simple configuration.
[0018]
Moreover, since the second end of the rod retainer elastically presses the output member against the power piston, the valve is added to the reaction force member and the output member when the brake pedal is returned and the valve seat member moves forward. The reaction force from the seat member is reliably supported by the second end of the rod retainer. For this reason, there is no axial gap between the reaction force member and output member and the power piston, and the re-engagement of the valve seat member with the holding means is ensured.
[0019]
Further, the front end surface of the second end of the rod retainer is disposed rearward of the front end surface of the power piston, so that the front end surface of the power piston and the front end surface of the housing can be accommodated even during a full stroke forward of the power piston. The second end portion of the rod retainer is not sandwiched between the protruding portions and the second end portion of the rod retainer is reliably prevented from being deformed or damaged.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
1 and 2 are sectional views of a negative pressure booster for a vehicle according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of FIG.
[0022]
In FIG. 1, a negative pressure booster 10 for a vehicle includes a front shell 11, a rear shell 12, and a movable wall 20. The housing is divided into a constant pressure chamber 23 and a variable pressure chamber 24 by the movable wall 20. 14. The movable wall 20 in the housing 14 includes a metal plate 18 and a rubber diaphragm 19, and is installed so as to be movable in the front-rear direction with respect to the housing 14.
[0023]
The bead portion on the outer peripheral edge of the diaphragm 19 is airtightly held between the folded portion provided on the outer peripheral edge of the rear shell 12 and the front shell 11. The bead portion on the inner peripheral edge of the diaphragm 19 is airtightly fixed together with the plate 18 in a groove provided on the outer periphery of the front flange portion of the power piston 22.
[0024]
The constant pressure chamber 23 communicates with an engine intake manifold (not shown) which is a negative pressure source, and is always kept at a negative pressure during engine operation. The variable pressure chamber 24 communicates and is disconnected from the constant pressure chamber 23 via the passage 60 and the valve mechanism 36, and is also communicated and blocked from the atmosphere via the valve mechanism 36.
[0025]
As shown in FIGS. 1 and 2, the power piston 22 has a first space 22 a located in the front (left side in FIGS. 1 and 2) and communicating with the constant pressure chamber, and a rear in the interior. It has a second space 22b that is located (right side in FIGS. 1 and 2) and communicates with the atmosphere, and an intermediate portion 221 that is interposed between the first space 22a and the second space 22b. The intermediate portion 221 communicates the first space 22a and the second space 22b separately from the third space 22c and the third space 22c that communicates the first space 22a and the second space 22b at the center of the intermediate portion 221. And a passage 60 to be connected.
[0026]
Inside the power piston 22, an input rod 28 and a plunger 37 constituting the input member 27 penetrate the first space 22 a, the second space 22 b, and the third space 22 c and can move in the front-rear direction with respect to the power piston 22. It is installed as follows. Further, the input rod 28 and the plunger 37 are integrally coupled by a coupling portion 80, and the input rod 28 is coupled to a brake pedal (not shown) at the rear thereof.
[0027]
As shown in FIGS. 1, 2, and 5, a rod retainer 15 in which a tongue piece 15 b and a base portion 15 a are integrally connected by a connecting portion 15 c is provided on the outer periphery of the front end portion of the power piston 22. The base portion 15a is pressed against the power piston 22 by the spring 57, and the tongue piece 15b engaged with the groove 22e of the front end surface 22f of the power piston 22 presses the flange portion of the output member 55 elastically. Regulates withdrawal to the front.
[0028]
Further, the front end face 15b1 of the tongue piece 15b is located rearward of the front end face 22f of the power piston 22, and the front end face 22f of the power piston 22 is also connected to the housing 14 even when the power piston 22 has made a full stroke forward. The tongue piece 15b of the rod retainer 15 is not sandwiched between the front end surface 22f of the power piston 22 and the forward inward projection portion 14a of the housing 14, so that the tongue piece The deformation and breakage of 15b are reliably prevented.
[0029]
As shown in FIG. 6, the rod retainer is a rod formed by integrating a ring portion 115d and a base portion 115a by a plurality of tongue-like rim portions 115b extending inward in the radial direction and a connecting portion 115c. The retainer 115 may be used. In this case, an appropriate elastic force for pressing the output member 55 against the power piston 22 is obtained, and the rim portion 115b and the ring portion 115d are integrally formed, so that the strength is high. In addition, since the rim portion 115b is engaged with a plurality of grooves 22e provided in the circumferential direction on the front end surface of the power piston 22, the rod retainer 115 can be easily and reliably assembled.
[0030]
In the present embodiment, considering that the rod retainer is applied to a negative pressure type booster having an emergency brake function, which will be described later, the tongue piece 15b presses the flange portion of the output member 55 elastically. However, the present invention is not necessarily limited to this. That is, in a normal negative pressure booster that does not have an emergency brake function, the tongue piece 15b does not have to press the flange portion of the output member 55 elastically, and a slight gap may be set. .
[0031]
An output member 55 is fitted to the front end portion of the power piston 22, and a reaction force member 54 is disposed between the front end portion of the power piston 22 and the output member 55. Further, a contact member 70 is disposed between the reaction force member 54 and the front end portion of the plunger 37, and the contact member 70 transmits the output of the output member 55 transmitted via the reaction force member 54. A part of the reaction force corresponding to is transmitted to the plunger 37.
[0032]
In order to define the amount of movement of the plunger 37 and the input rod 28 with respect to the power piston 22, the key member 32 is inserted into the radial hole 33 formed in the intermediate portion 221 of the power piston 22. The thickness dimension of the key member 32 in the front-rear direction (left-right direction in FIGS. 1 and 2) is smaller than the dimension of the radial hole 33 in the front-rear direction. It can move in the front-rear direction by the indicated distance C.
[0033]
The key member 32 can come into contact with the rear shell 12 at the rear surfaces of both ends protruding to the outer peripheral side of the power piston 22, and the limit of movement of the power piston 22 to the rear with respect to the housing 14 is as shown in FIG. In addition, the front wall of the radial hole 33 is in contact with the front surface of the key member 32, and the rear surfaces of both ends of the key member 32 are in contact with the rear shell 12. The central portion of the key member 32 is disposed between a pair of flange surfaces 34, 35 formed at the central portion of the plunger 37, and the rearward movement limit of the plunger 37 relative to the power piston 22 is determined by the flange surface 34. This is the position where the front surface of the key member 32 abuts and the rear surface of the key member 32 abuts the rear wall of the radial hole 33. The forward movement limit of the plunger 37 with respect to the power piston 22 is such that the flange surface 35 is in contact with the rear surface of the key member 32 and the front surface of the key member 32 is in contact with the front wall of the radial hole 33. is there.
[0034]
Inside the power piston 22, an output reducing action state in which the variable pressure chamber 24 is communicated with the constant pressure chamber 23 and cut off from the atmosphere while the plunger 37 moves in the front-rear direction relative to the power piston 22, and 23 and a valve mechanism 36 for switching between an output holding action state that is shut off from the atmosphere and an output increasing action state in which the variable pressure chamber 24 is shut off from the constant pressure chamber 23 and communicated with the atmosphere.
[0035]
The valve mechanism 36 includes an atmospheric valve seat 37a formed integrally with the rear end of the plunger 37, and a first negative pressure valve seat formed integrally with the power piston 22 around the rear side opening of the third space 22c. 38, a movable part 41 having a negative pressure valve seat 41a and an atmospheric valve seat 41b facing the first negative pressure valve seat 38 and the atmospheric valve seat 37a, respectively, and a fixed fixed to the power piston 22 by a retainer 42. A cylindrical member 45 having a portion 43 and the movable portion 41 being urged forward by a spring 44 is a main constituent member.
[0036]
In the third space 22c of the intermediate portion 221, a valve seat member 40 on which a second negative pressure valve seat 39 is formed is disposed concentrically with the first negative pressure valve seat 38, and in the front-rear direction with respect to the power piston 22. It can be moved.
[0037]
As shown in a perspective view in FIG. 3, the valve seat member 40 includes a slit 40 b into which an abutting portion 37 c that protrudes in the radial direction is inserted into the outer periphery of the plunger 37, and a through hole that penetrates the valve seat member 40 in the front-rear direction. 40e. Further, the key member 32 is inserted across the connecting portion 40a.
[0038]
By inserting the plunger 37 into the through hole 40e of the valve seat member 40, the contact portion 37c and the slit 40b face each other, and the contact portion 37c protrudes outside the valve seat member 40 through the slit 40b. Will do. When the plunger 37 provided with the valve seat member 40 is disposed in the power piston 22, the contact portion 37 c comes into contact with the concave portion 221 a on the inner peripheral surface of the intermediate portion 221. It is slidably supported on the inner periphery of the intermediate portion 221, that is, the inner periphery of the power piston 22 via 37 c.
[0039]
On the other hand, the valve seat member 40 is located between the outer peripheral portion of the plunger 37 and the inner peripheral portion of the intermediate portion 221 of the power piston 22, and the intermediate portion 221 at the rear end where the first negative pressure valve seat 38 is formed. It will contact | abut to the inner peripheral surface of this so that sliding is possible in the front-back direction. That is, the power piston 22 includes the intermediate portion 221 as a holding portion that holds the valve seat member 40 so as to be slidable in the front-rear direction.
[0040]
An annular seal member 46 that keeps an airtight seal between the rear end portion of the valve seat member 40 and the inner peripheral surface of the intermediate portion 221 is attached to the outer periphery of the rear end portion that contacts the intermediate portion 221 of the valve seat member 40. Yes. Further, the valve seat member 40 is urged rearward by a spring 47 disposed between the valve seat member 40 and a flange portion provided on the inner peripheral surface of the intermediate portion 221.
[0041]
A spring 59 disposed between a retainer 58 that is locked to the input rod 28 that is integrally connected to the plunger 37 and the coupling portion 80 and a retainer 42 that is locked to the power piston 22 is provided to the input rod 28. When the brake pedal is not depressed, the atmospheric valve seat 37a is brought into contact with the movable portion 41 of the valve mechanism 36, and the movable portion 41 is separated from the first negative pressure valve seat 38 by a distance A. Hold it in a state.
[0042]
The passage 60 formed in the intermediate portion 221 and the first space 22a communicate the valve mechanism 36 and the constant pressure chamber 23, and the third space 22c communicates the valve mechanism 36 and the variable pressure chamber.
[0043]
A movable means for propelling the valve seat member 40 rearward is disposed inside the front portion of the power piston 22, that is, in the intermediate portion 221. The movable means includes a spring 47 and a key member 32 that urge the valve seat member 40 rearward.
[0044]
A holding means 48 is disposed inside the front portion of the power piston 22, that is, in the first space 22a. The holding means 48 includes a holding member 52 having a first engaging portion 52b that engages with the engaged portion 40c of the valve seat member 40, and a ring-shaped elastic body 53 that urges the holding member 52 in a direction to reduce the diameter. Thus, the second engaging portion 52 c of the holding member 52 is fitted in the locking groove 50 a of the auxiliary holding member 50 fixed to the front portion of the power piston 22. For this reason, the holding member 52 cannot move in the front-rear direction, but is allowed to move in the radial direction around the second engagement portion 52c. As shown in FIG. 4, the holding member 52 has a three-divided hollow truncated cone shape obtained by cutting the hollow truncated cone in three planes passing through its central axis, and three three-divided hollow truncated cones are opposed to each other. Then, it is assembled to the power piston 22 via the auxiliary holding member 50.
[0045]
The auxiliary holding member 50 also functions as a guide member that guides the movement of the contact member 70 in the front-rear direction.
[0046]
A cam is constituted by an inclined surface portion 52 a provided in the inward flange portion of the holding member 52 and an inclined surface portion 37 b provided in the forward outward urange portion of the plunger 37, and the plunger 37 moves forward by a predetermined amount with respect to the power piston 22. When the relative movement is performed, the holding member 52 is moved in the radial direction by a cam action, and the engagement between the engaging portion 52b and the engaged portion 40c of the valve seat member 40 is released.
[0047]
Next, the operation of the negative pressure booster according to the present embodiment will be described. However, the operation as a negative pressure booster during normal braking is generally known, so the description thereof will be omitted. The operation during emergency braking will be described.
[0048]
The emergency braking characteristics of the negative pressure booster of this embodiment are achieved by changing the jumping characteristics described above and applying a larger driving force to the output member than during normal braking. In order to change the jumping characteristics, the gap D between the contact member 70 and the reaction force member 54 in FIG. The gap D is enlarged by the distance between the contact surface 22d of the power piston 22 to the reaction force member 54 and the negative pressure valve seat 38, and the contact surface 22d of the power piston 22 to the reaction force member 54 and the atmospheric valve seat 37a. Is the same as expanding the distance. That is, by moving the negative pressure valve seat 38 and the atmospheric valve seat 37a rearward, the gap D is expanded, the output until the contact member 70 receives the reaction force from the reaction force member 54 is increased, and the output with respect to the input is increased. The output in the so-called jumping state in which the ratio of is infinite is made larger than in the normal state.
[0049]
If the relative movement amount between the input rod 28 and the power piston 22 exceeds a predetermined value B during emergency braking when the driver rushes and depresses the brake pedal, the inclined surface portion 37b of the plunger 37 becomes the tapered portion 52a of the holding member 52. At the same time, the holding member 52 urged in the direction of reducing the diameter by the ring-shaped elastic body 53 is expanded in the radial direction.
[0050]
When the minimum inner diameter portion 52aa of the slope portion 52a rides on the stepped portion 37d of the plunger 37, the engagement between the engaged portion 40c of the valve seat member 40 and the engaging portion 52b of the holding member 52 is released. Since the valve seat member 40 is urged rearward by the spring 47, as soon as the engagement of the engaged portion 40c is released, the valve seat member 40 moves rearward by the urging force of the spring 47.
[0051]
When the valve seat member 40 moves rearward, the second negative pressure valve seat 39 of the valve seat member 40 abuts on the valve 41a constituting the movable portion 41 of the valve mechanism 36, and the constant pressure chamber 23 and the variable pressure chamber 24 are communicated. Cut off. At this time, since the plunger 37 is moving forward together with the input rod 28 and the valve seat member 40 pushes back the movable portion 41 of the valve mechanism 36, the valve 37 and the air valve seat 37a of the plunger 37 The valve 41b constituting the movable part 41 of the mechanism 36 is rapidly separated, and the variable pressure chamber 24 communicates with the atmosphere. As a result, compared with the normal brake operation, the communication between the constant pressure chamber 23 and the variable pressure chamber 24 is rapidly cut off and the variable pressure chamber 24 is communicated with the atmosphere, and the power piston 22 is substantially connected to the reaction force member 54. The distance between the contact surface 22d and the first negative pressure valve seat 38 and the distance between the contact surface 22d of the power piston 22 to the reaction force member 54 and the atmospheric valve seat 37a are increased, and output in a jumping state is achieved. Can be made larger than the normal state.
[0052]
The normal brake characteristics and the emergency brake characteristics are shown in FIG. In FIG. 7, the jumping in the normal brake is F₀₁However, jumping during emergency braking is F₀₁₁Thus, a sufficiently large brake fluid pressure can be generated with a small pedal effort.
[0053]
When the brake operation is finished and the brake pedal is returned, the plunger 37 moves rearward while the flange surface 34 is in contact with the key member 32. When the key member 32 comes into contact with the rear shell 12, the key member 32 comes into contact with the front groove wall 40 f of the valve seat member 40, and the rearward movement of the valve seat member 40 that has been retracted integrally with the power piston 22 is restricted. To do. At this time, since the power piston 22 is still retracted, the engaging portion of the holding member 52 that is integrally retracted with the power piston 22 is in contact with the rear shell 12 via the key member 32 and is stationary. To be engaged with the engaged portion 40c of the member 40, the holding member 52 disengaged by the emergency brake operation and the valve seat member 40 are re-engaged to prepare for the next emergency brake operation. Become.
[0054]
【The invention's effect】
According to the present invention, even when the power piston makes a full stroke forward, the second end portion of the rod retainer is not deformed or damaged, and the detachment of the output member from the power piston can be reliably regulated. A negative pressure booster can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a negative pressure booster according to an embodiment of the present invention.
FIG. 2 is an enlarged partial view of a main part of FIG.
FIG. 3 is a perspective view before the valve seat member 40 is assembled.
FIG. 4 is a perspective view before the holding member 52 is assembled.
FIG. 5 is a view as viewed from A in FIG. 1 showing a mounted state of the rod retainer 15;
6 is a view as seen from A in FIG. 1 showing a mounting state of the rod retainer 115. FIG.
7 is a diagram showing the relationship between the force (input) applied to the input rod 28 and the propulsive force (output) of the output member 55. FIG.
[Explanation of symbols]
10 Negative pressure booster
12 Rear shell (return means)
14 Housing
15 Rod retainer
15a Base (first end)
15b Tongue piece (second end)
15b1 Front end surface of tongue
20 movable wall
22 Power piston
22e Groove
22f Front end face of power piston
23 constant pressure chamber
24 Transformer room
27 Input members
28 Input rod (input member)
32 Key members (movable means, return means)
37 Plunger (input member)
38 First negative pressure valve seat
39 Second negative pressure valve seat
47 Spring (movable means)
48 Holding means
50 Auxiliary holding member (holding means)
52 Holding member (holding means)
53 Ring-shaped elastic body (holding means)
54 Reaction force member
55 Output member
57 Spring (biasing member)
115 Rod retainer
115a base (first end)
115b Rim part (second end)
115d Ring part (second end)

Claims (4)

A housing forming at least one pressure chamber therein;
A movable wall installed inside the housing so as to be capable of moving forward and backward with respect to the housing and dividing the pressure chamber into a constant pressure chamber and a variable pressure chamber;
A power piston coupled to the movable wall;
An input member installed inside the power piston so as to be movable forward and backward with respect to the power piston;
An output member that outputs the propulsive force of the power piston accompanying the movement of the movable wall to the outside of the device;
A rod retainer provided with a first end abutting on the power piston and a second end for restricting separation of the output member from the power piston ;
In the negative pressure type booster in which the front end surface of the power piston and the inward protruding portion in front of the housing abut when the power piston makes a full stroke forward ,
Ri rearward near than the front end surface of the front end surface of the second end of the rod retainer is the power piston,
The second end of the rod retainer includes a plurality of tongue pieces extending radially inward, and the tongue pieces engage with a plurality of grooves provided in a circumferential direction on the front end face of the power piston. A negative pressure booster. A housing forming at least one pressure chamber therein;
A movable wall installed inside the housing so as to be capable of moving forward and backward with respect to the housing and dividing the pressure chamber into a constant pressure chamber and a variable pressure chamber;
A power piston coupled to the movable wall;
An input member installed inside the power piston so as to be movable forward and backward with respect to the power piston;
An output member that outputs the propulsive force of the power piston accompanying the movement of the movable wall to the outside of the device;
A rod retainer provided with a first end abutting on the power piston and a second end for restricting separation of the output member from the power piston ;
In the negative pressure type booster in which the front end surface of the power piston and the inward protruding portion in front of the housing abut when the power piston makes a full stroke forward ,
Ri rearward near than the front end surface of the front end surface of the second end of the rod retainer is the power piston,
The second end of the rod retainer includes a plurality of tongue-shaped rim portions extending radially inward and a ring portion for connecting the rim portions in the circumferential direction. A negative pressure booster , wherein the rim portion engages with a plurality of grooves provided in a direction . In any one of claim 1 or claim 2, the second end of the rod retainer, the vacuum servo characterized by repulsive manner pressed against the output member to the power piston device . The reaction force according to any one of claims 1 to 3 , wherein the reaction force is transmitted to the input member according to the output of the negative pressure valve seat disposed on the power piston and facing backward and the output member. A force mechanism, and a valve mechanism having a movable part facing the negative pressure valve seat and a fixed part airtightly fixed to the power piston, the negative pressure valve seat being integrated with the power piston. The first negative pressure valve seat and a second negative pressure valve seat provided on a valve seat member substantially concentric with the first negative pressure valve seat and capable of moving forward and backward relative to the power piston, and the power of the input member A holding means for holding the valve seat member at a predetermined position forward when the advance amount relative to the piston is less than a predetermined value, and a valve seat member when the advance amount relative to the power piston of the input member is greater than a predetermined value. A negative means characterized by comprising a movable means for moving the valve seat by a predetermined amount, and a return means for returning the valve seat member to a predetermined forward position when the power piston is in a predetermined position relative to the housing. Pressure booster.

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