JPS6067253A - Negative-pressure booster - Google Patents

Abstract

PURPOSE:To simplify seal structure by forming a series of bulged parts onto the annular inner peripheral bead of a piston diaphragm and strongly pressing said bulged parts in the direction of the center line and outwardly in the radial direction of the insertion hole of the diaphragm by the flange for preventing the slip- off of a valve cylinder and the tapered surface of the valve cylinder. CONSTITUTION:The inner peripheral bead 58 of a piston diaphragm 6 is fitted onto the opened edge of the insertion hole 41 of a booster piston 5, and said inner peripheral bead 58 has, in free state, a series of bulged parts 58a which project to the front-surface side 5a of the booster piston 5 and into the insertion hole 41, as shown by the chain line. When a flange 45 for preventing the slip- off of a valve cylinder 14 is locked between a locking plate 50 and the booster piston 5, said bulged part 58a is strongly pressed in the direction of the center line of the insertion hole 41 as shown by the arrow (b) by the slip-off preventing flange 45, and outwardly in the radial direction of the insertion hole 41 as shown by the arrow (c) by the tapered surface 46 of the valve cylinder 41, and compressed into the annular concaved part 62 on the periphery of the insertion hole 41. Thus, certain seal is secured between the valve cylinder 41 and the booster piston 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative pressure booster used, for example, in operating a brake mask cylinder of a vehicle.

Conventionally, this type of device has a booster piston that can freely reciprocate back and forth within the booster shell, a first working chamber at the front that is constantly in communication with a negative pressure source by a piston diaphragm attached to the rear surface of the booster piston, and a control chamber. It is known that the booster piston is divided into a first working chamber or a second working chamber in the rear part of which is alternately controlled to communicate with the atmosphere (F) through a valve, and a valve cylinder is provided in which the booster piston accommodates the control valve. .

In the above device, if the booster piston is constructed in an assembled manner with the valve cylinder, it is economical because the booster piston can be changed and used in common with the valve cylinder when manufacturing products with various output characteristics. However, conventionally, the booster piston and the valve barrel are integrally molded from synthetic resin, so the above effects cannot be obtained.

On the other hand, if the valve m is assembled to the booster piston, the sealing structure between them becomes a problem.

In view of the above, the present invention configures the valve cylinder to be assembled to the booster piston, so that the valve cylinder can be easily assembled, and the valve cylinder can be commonly used when manufacturing boosters having various output characteristics. The purpose of the present invention is to provide a booster which improves economical efficiency, simplifies the sealing structure between the booster piston and the valve cylinder, and enables reliable sealing. A series of bulges protruding toward the first working chamber and inward of the insertion hole are provided on the annular inner circumferential bead of the piston diaphragm that is fitted into the opening edge of the valve cylinder fitting hole, and the piston diaphragm is fitted into the fitting hole for the valve cylinder. a cylindrical body, and a retaining flange provided on the outer circumferential surface of one end of the body and located on the first working chamber side, and a retaining flange on the connecting portion of the main body with the retaining flange side facing the larger diameter side. A retaining flange is sandwiched between the booster piston and a retaining plate that forms a tapered surface and is retained by a plurality of retaining pawls protruding from the first working chamber side of the booster piston, thereby preventing the retainer from coming off. The feature is that the bulge of the inner peripheral bead is strongly pressed outward in the centerline direction and radial direction of the insertion hole by the flange and tapered surface.

Hereinafter, an embodiment in which the present invention is applied to a brake mask cylinder will be described with reference to the drawings.

In Fig. 1, booster shell I of negative pressure booster S
Fi Consists of a pair of front and rear bowl-shaped bodies 1F and 1R molded from lightweight thin-walled steel plate or synthetic resin, and a plurality of claw pieces 2 protruding from the opening of the rear bowl-shaped body 1R at equal intervals on the circumference.
are engaged with a plurality of notches 3 formed at equal intervals on the circumference in the opening of the front bowl-shaped body 1F, and the mutual positioning of both arm-shaped bodies 1F and 1R is performed via a pair of tie rods 4. are connected. The connection structure between the booster shell 1 and the tie rod 4 will be described later.

The inside of the booster shell 1 is divided into a first working chamber A at the front and a second working chamber A at the rear by a booster piston 5 housed therein so as to be able to reciprocate back and forth, and a piston diaphragm 6 attached to the rear surface 5h of the booster piston 5. It is divided into a working chamber B.

The first working chamber A is always in communication with the intake manifold (not shown) of the internal combustion engine, which is a negative pressure source, through the negative pressure introduction pipe 7.
The second working chamber B is connected to the first working chamber A via a control valve 8, which will be described later.
Alternatively, the air inlet 11 opened in the end wall 10 of the rear extension tube 9 of the booster shell 1 is alternately connected and controlled.

The booster piston 5 is always regulated in the backward direction by a return spring 12 contracted in the first working chamber A, that is, by the protrusion 13 formed protuberantly formed on the back surface of the second actuating shuffle ram 3 abutting against the inner surface of the rear wall of the booster cylinder 1. be done.

The booster piston 5 is provided with a valve cylinder 14 that protrudes rearward from its center, and the valve cylinder 14 is slidably supported by a flat bearing 15 provided on the extension cylinder 9, and its rear end is connected to the atmosphere introduced into the cylinder 9. It is also opened towards the mouth 11.

The control valve 8 is configured in the valve cylinder 14 as follows. That is, an annular first valve seat 16. is provided on the front inner wall of the valve cylinder 14. A valve piston 18 connected to the input rod 17 and forming the front end thereof is slidably connected to the front part of the valve cylinder 14, and the first valve seat 16. is formed at the rear end of the valve piston 18. An annular second valve seat 162 surrounded by the valve seat 162 is formed.

A base end portion 20 of a cylindrical valve body 19 with both ends open is held on the inner wall of the valve cylinder 14 via a valve body holding cylinder 21 that is fitted into the valve cylinder 14 . The valve body 19 is made of an elastic material such as rubber, and a thin diaphragm 22 extends radially inward from its base end 20, and a thick valve portion 23 is connected to the inner peripheral end thereof. The valve portion 23 faces the first and second valve seats 16+ and 16□. Therefore, valve part 2
3 can move back and forth by deforming the diaphragm 22, and can also come into contact with the front end surface of the valve body holding cylinder 21.

An annular reinforcing plate 24 is embedded in the valve portion 23, and a valve spring 25 is connected to this to bias the valve portion 23 toward both valve seats 161 and 162.

The outer part of the first valve seat 16□ is connected to the first working chamber A through a pair of through holes 26 of the booster piston 5, and to the first and second
Valve seat 16. ．． The middle part of the valve seat 16□ is always in communication with the second working chamber B through another pair of through holes 2T, and the inner part of the second valve seat 16□ is in constant communication with the atmosphere inlet 11 through the inside of the valve body 19. .

The booster piston 5 is provided with a large-diameter cylinder hole 28 that opens at the center of its front surface, and a small-diameter cylinder hole 29 that opens at the inner end surface of the cylinder hole 28. An elastic piston 30 made of rubber or the like and an output piston 31 of the same diameter are sequentially slid together from the back, and an elastic piston 3 is inserted into the small diameter cylinder hole 29.
A reaction piston 32 having a diameter smaller than 0 is slid together. Furthermore, a small shaft 33 protruding from the front end surface of the valve piston 18 enters the small diameter cylinder hole 29 and opposes the rear end surface of the reaction piston 32 . An output rod 34 is located in front of the output piston 31.
is provided in a protruding manner, and its output rod 34 is disposed within the first working chamber A.

The input rod 17 is always urged in the backward direction by the return spring 37, and its retreat limit is reached when the movable stopper plate 35 screwed onto the input rod 17 comes into contact with the inside of the end wall 10 of the rear extension tube 9. regulated by.

When the movable stopper plate 35 is rotated, the screwing position between the movable stopper plate 35 and the input rod 17 changes, so that the retraction limit of the input rod 17 can be adjusted back and forth. After the adjustment, the movable stopper plate 35 is fixed by tightening a lock nut 36 which is also screwed onto the input rod 17. A vent hole 38 is formed in the movable stopper plate 35 so that the movable stopper plate 35 does not block the air inlet 11.

Filters 39 and 40 are attached to the outer end opening of the valve cylinder 14 to purify the air introduced from the atmospheric air inlet 11 and to be deformable so as not to interfere with the operation of the input rod 17.

Next, the assembly structure of the valve cylinder 14 to the booster piston 5 will be explained. As shown in Figs. A cylinder fitting hole 41 is formed. Further, the booster piston 5 includes a pair of arc-shaped reinforcing ribs 42 that are arranged so as to surround the insertion hole 41 and protrude from the front surface 5a, and a front surface 5a with tips facing each other on the outside of both reinforcing ribs 42; A pair of locking claws 43 are provided which are cut and raised to the side. Both image retaining claws 43 are biased to one side of both reinforcing lips 42 and are arranged point-symmetrically with respect to the center of the insertion hole 41.

The valve cylinder 14 is molded from thermosetting synthetic resin such as phenol resin, and has a cylindrical main body 44 and a retaining flange 45 protruding from the outer peripheral surface of one end of the main body 44. The outer circumferential surface of the connecting portion with the retaining flange 45 is formed into a tapered surface 46 with the flange 45 side being the larger diameter side. The retaining flange 45 has the large-diameter cylinder hole 28 on its end face, a truncated conical short cylindrical portion 47 concentric with the main body 44, and a flat top surface 48 disposed to sandwich the short cylindrical portion 47. A pair of protrusions 49 are provided, and one of the through holes 26 is opened at the top surface 48 of the protrusions 49 .

Further, the other through hole 27 is opened on the small diameter side of the tapered surface 46.

The locking plate 50 includes a flat plate part 52 having a truncated conical cap part 51 into which the short cylindrical part 47 can be fitted loosely, and the flat plate part 52.
A pair of leg parts 35 are bent diagonally in a direction opposite to the protruding direction of the cap part 51 from both ends of the cap part 51, and a pair of locking parts 54 extend further outward from both ends of both leg parts 53. . The connecting portion between the flat plate portion 52 and the leg portion 53 is formed in an arc shape along the outer periphery of the retaining flange 45, and the connecting portion between the leg portion 53 and the locking portion 45 is formed in an arc shape along the outer periphery of the reinforcing lip 42. Each is formed.

Reinforcing edges 55 are formed by bending on both side edges of the locking plate 50 except for one end of both image locking portions 54 which are point symmetrical with respect to the center of the cap portion 51 .

A through hole 56 having a smaller diameter than the output piston 31 and a larger diameter than the output rod 34 is formed in the top wall of the cap portion 51, and a pair of through holes 56 communicating with the through hole 26 are formed on the base end side of the cap portion 51 of the flat plate portion 52. A communication hole 57 is formed.

When assembling the valve cylinder 14 to the booster piston 5, the main body 44 of the valve cylinder 14 is inserted into the insertion hole 41 of the booster piston 5 from the front face 5a side, and the retaining flange 45 is positioned inside both reinforcing lips 42. and polymerizes into the booster piston 5. Then, as shown in FIG. 4, the cap part 51 of the locking plate 50 is loosely fitted into the short cylinder part 47, and the connecting part between the flat plate part 52 and the leg part 53 is closed at the position where the locking claw 43 is released. The outer circumferential edge of the retaining flange 45 and the connecting portion between the leg portion 53 and the locking portion 54 are aligned with the outer circumferential edge of the reinforcing rib 42, and from this state, the locking plate 5o is connected to the leg portion 53 and the locking portion. When the connecting portion with the reinforcing rib 42 is brought into contact with the reinforcing rib 42 and rotated in the direction of the arrow α in FIG.
is locked with the locking pawl 43, and at the same time, the flat plate portion 52 is locked with the protruding portion 49.
As a result, the retaining flange 45 is caught between the locking plate 50 and the booster piston 5, and the valve cylinder 1
5 is assembled to the booster piston 5. In this case, the reinforcing edge 55 located at one end of the locking part 54 abuts against the edge of the locking pawl 43, and the rotation angle of the locking plate 50 is regulated. The holes 26 match. Further, the movable end of the return spring 12 engages with the cap portion 51 of the locking plate 50, and the locking plate 50 is prevented from rotating by the elastic force of the return spring 12.

The output rod 34 is loosely inserted into the through hole 56 of the cap portion 51, but since the diameter of the through hole 56 is smaller than that of the output piston 31, the cap portion top wall 51. z functions as a stopper piece that faces the opening of the cylinder hole 28 and faces the output piston 31, thereby causing problems such as the output piston 31 and the output rod 34 falling from the valve cylinder 14 when the booster piston 5 is assembled. There is no.

1st. As shown in FIG. 3, the piston diaphragm 6 is formed with annular inner and outer peripheral beads 58 and 59, and the outer peripheral bead 59 has a positioning protrusion 60 protruding from its end surface in a rear bowl shape. It is fitted into each positioning hole 61 formed on the outer periphery of the body 1R and sandwiched between the arm-like bodies 1F and 1R.

The inner peripheral bead 58 is fitted into the edge of the insertion hole 410 of the booster piston 5, but the inner peripheral bead 58 is attached to the front surface 5α side of the booster piston 5 and the insertion hole 41 in a free state as shown by the chain line in FIG. A series of bulges 58α projecting inward are formed. This bulge 58. Z is the direction of the center line of the insertion hole 41 as shown by the arrow when the retaining flange 45 of the valve cylinder 14 is clamped between the locking plate 50 and the booster piston 5 as described above. In addition, the tapered surface 46 of the valve cylinder 14 presses strongly outward in the radial direction of the fitting hole 41 as shown by arrow C, and the valve cylinder 14 is compressed into the annular recess 62 around the fitting hole 41, thereby creating a space between the valve cylinder 14 and the booster piston 5. will be securely sealed.

The pressure receiving portion 63 of the piston diaphragm 6 is in close contact with the rear surface of the booster piston 5, and protrudes toward the first working chamber A between the outer circumferential surface of the booster piston 5 and the inner circumferential surface of the front bowl-shaped body 1F. 5 It is bent into a U shape, and this U
The booster piston 5 moves forward due to the transfer of the bent portion,
It is designed to allow for setbacks.

1st. As shown in FIG. 5, an opening 64 is formed in the portion of the booster piston 5 where the locking claw 43 is cut and raised, and the connection between the booster piston 5 and the piston diaphragm 6 is established through the opening 64 during the first operation. Since they are communicated with chamber A, no air pockets will be generated between them. Further, the portion of the piston diaphragm facing the opening 64 is formed into a thick wall portion 65, whereby the atmosphere is introduced into the second working chamber B, and the air pressure in the second working chamber B is changed to the first working chamber. Even if the height is higher than that of A, the thick portion 65 does not bulge into the opening 64, and therefore the piston diaphragm 6
Damage caused by the opening 64 can be prevented.

Next, the connection structure between the tie rod 4 and the booster shell 1 will be explained.

As shown in FIG. 1, the tie rod 4 has a mounting bolt 66 that penetrates the front wall of the booster shell 1 and projects forward.
are integrally formed, and a spring receiving plate 67 that comes into contact with the inner surface of the front wall of the booster shell 1 is fixed. Then, the mounting bolt 66 is passed through the mounting flange 68 of the brake mask cylinder M stacked on the front surface of the booster shell 1, and a nut 69 is screwed onto the tip of the bolt 66 and tightened.
The spring receiving plate 67, the front wall of the booster shell, and the surround of the mounting flange 68 are connected together. At this time, an annular seal member 71 that seals the tie rod through hole in the front wall of the booster shell 1 is fitted into an annular groove 70 formed on the front surface of the spring receiving plate 67 so as to surround the bolt 66 . The spring receiving plate 67 supports the fixed end of the return spring 12, and allows the elastic force of the return spring 12 to be borne by the tie rod 4, thereby removing the load on the booster shell 1.

Further, the tie rod 4 is integrally formed with a mounting bolt 72 that penetrates the rear wall of the booster shell 1 and projects rearward thereof, and a stepped flange 73 that abuts the inner surface of the rear wall of the booster shell 1. The stepped franchise 3 is fitted into a support tube 74 that is welded and fixed to the inner surface of the rear wall of the booster shell 1, and its retaining ring 75 is locked to the support tube 74 to connect the tie rod 4 and the rear wall of the booster shell 1. are connected together. At this time, an annular seal member 77 that seals the tie rod through hole in the rear wall of the booster shell 1 is fitted into the annular groove 76 between the small diameter portion of the stepped flange 73 and the support tube 74 .

The mounting bolt 72 is passed through the front wall W of the vehicle compartment, and the tie rod 4 is fixed to the front wall W of the vehicle compartment by screwing and tightening the nut 18 at its tip.

Thus, the booster shell 1 is attached to the single-chamber front wall W via the tie rod 4, and is also attached to the brake mask cylinder M.
are connected to the booster shell 1 via tie rods 4.

Next, a seal structure between the tie rod 4, booster piston 5, and piston diaphragm 6 will be explained.

The booster piston 5 has a first. As shown in FIG. 3, a pair of tie rod penetration holes 79 are formed between both reinforcing lips 42, and a plurality of notches 80 (three in the illustrated example) are formed at equal intervals on the circumference at the rim. It is located at 111'.

Further, the piston diaphragm 6 is also formed with through holes 81 corresponding to the through holes 79, and the rim of each through hole 81 has a thick wall portion 8.
2 is formed.

Third. As shown in FIG. 6, three locking pawls 84 corresponding to the notches 80 are provided at one end of the outer peripheral surface of the two seal mounting tubes 83, and four tool locking claws are provided at the other end. A retaining flange 86 having a mating portion 85 is provided in a protruding manner. The top surface 84a of each locking pawl 84 is formed with a fitting guide inclined surface 84I5 that slopes downward from the intermediate portion toward the end surface of the seal mounting tube 83, and the rising surface 84C has one end formed from the intermediate portion. A rotation guiding inclined surface 84d is formed with a downward slope toward. The direction of inclination of the rotation guiding inclined surface 84d in each locking pawl 84 is the same.

The seal mounting tubes 83 are assembled to the booster piston 5 before the valve tube 14 is assembled to the booster piston 5. 84 is fitted into each notch 80 and inserted into the through hole 81° 79 of the piston diaphragm 6 and the booster piston 5.

In this case, the fitting guide slope B4h of the top surface 84α of each locking pawl 84 allows the seal mounting cylinder 83 to be smoothly fitted into the through hole 79 of the booster piston 5. And the 6th. As shown in FIG. 7, the short cylindrical part 8B of the tool 87 is engaged with the seal mounting cylinder 83, and each of the engaging protrusions 89 on the outer peripheral surface of the short cylindrical part 88 is engaged with each of the tool engaging recesses 85, and the booster piston is still attached. 5 by applying the receiver 90 to the front surface 5α of the booster piston 5 and pressing the tool 87.
2 while rotating the handle 91 in the direction of arrow d in FIG. As a result, each locking pawl 84 is misaligned with each notch 80, and the rising surface 84C of each locking pawl 84 and the retaining flange 8
The booster piston 5 and the edges of the through holes 79, 810 of the piston diaphragm 6 are sandwiched between the booster piston 5 and the seal mounting cylinder 83, and the space between the booster piston 5 and the seal mounting cylinder 83 is sealed. In this case, the rotation guiding inclined surface 84 of the rising surface 84C of each locking pawl 84
d, each locking pawl 84 engages with the through hole 79 of the booster piston 5.
It smoothly enters the zero edge and the clamping is performed reliably.

Second. As shown in FIG. 3, the retaining flange 4 of the valve cylinder 14
5 includes adjacent locking claws 84 on both seal mounting tubes 83.
Notch 92 having a concave arc-shaped inner circumferential surface that can match the outer circumferential surface between
is formed, and when the valve cylinder 14 is fitted into the insertion hole 41 of the booster piston 5 and each notch 92 and each seal mounting cylinder 83 are fitted with the concave and convex portions as described above, each notch 92 in the retaining flange 45 is formed. Locking claws 84 whose outer peripheral surfaces near both ends are adjacent to each other
is engaged with the side surface 84h of the valve cylinder 14 and the seal receiving cylinder 8.
3. Mutual rotation is stopped. As another rotation preventing means, as shown in FIG. 8, a groove 93 which can be engaged with one locking pawl 84 may be formed in the notch 92 of the retaining flange 45 in the valve cylinder 14. good.

As shown in FIG. 1, the seal mounting tube 83 and tie rod 4
A sealing means is provided between them to allow the booster piston 5 to operate. The sealing means is constituted by a bellows-shaped retractable boot 94 made of an elastic material such as rubber, which surrounds the tie rod 4 in the first working chamber A and extends from the front end 94. Z is in the annular groove 95 of the tie rod 4,
The rear ends 94A are still fitted into the openings of the seal mounting tube 83, respectively.

In the vehicle interior, at the rear end of the input rod 17 of the booster S, there is a brake pedal 98 that is pivotally supported 97 on a fixed bracket 96.
are connected via a connecting fitting 99. 100 is a return spring that biases the brake pedal 98 rearward.

Cylinder body 101 of brake mask cylinder M.

The rear end passes through the front wall of the booster shell 1 and enters the first working chamber A.
The output rod 34 of the booster S is opposed to the rear end of the actuating piston 102 inside the cylinder body 101.

Next, to explain the operation of this embodiment, the state shown in FIG. 1 shows a non-operating state. 10 and is held by the spring force of the spring 37, and the valve piston 18 presses the front surface of the valve portion 23 via the second valve seat 162 to push it into the valve body holding cylinder 21. The first valve seat 161 is moved back until it lightly contacts the front surface, thereby forming a slight gap y between the first valve seat 161 and the valve portion 23. Such a state can be easily obtained by adjusting the movable strut plate 35 described above.

As described above, during engine operation, the first working chamber A, which always stores negative pressure, communicates with the second working chamber B through the through hole 26, the gap @J, and the through hole 27, and the front opening of the valve part 23. Since the section is closed by the second valve seat 16□, the negative pressure in the first working chamber A is transmitted to the second working chamber B, and the air pressures in both working chambers A and H are balanced.

Therefore, the booster piston 5 also occupies the illustrated retracted position by the elastic force of the return spring 12.

Now, step on the brake pedal 98 to brake the vehicle,
When the input rod 17 and the valve piston 18 are moved forward, the valve portion 23, which is urged forward by the valve spring 25, is moved forward by the valve piston 1.
8, but since the gap y between the first valve seat 161 and the valve part 23 is extremely narrow as described above, the valve part 23
Immediately, the second valve seat 162 seats on the first valve seat 161 to cut off communication between the two working chambers A and B, and at the same time, the second valve seat 162 separates from the valve portion 23 and passes through the second working chamber B through the hole 27 and inside the valve body 19. It communicates with the atmosphere inlet 11 via the air inlet port 11. Therefore, the second working chamber B
Atmospheric air is quickly introduced into the chamber B, and the pressure in the classroom B becomes higher than that in the first working chamber A. Due to the pressure difference between the two chambers A and B, the booster piston 5 moves forward against the return spring 12, causing the elastic piston 30 to move forward. Since the output rod 34 is advanced through the brake mask cylinder M, the actuating piston 102 of the brake mask cylinder M is driven forward, and the vehicle is braked.

When the operating piston 102 is driven, the cylinder body 10
A forward thrust load is applied to the vehicle 1, and this load is transmitted to the vehicle body, that is, the single-chamber front wall IV, through the tie rod 4, and is supported therein. Therefore, the above-mentioned load does not act on the booster shell 1.

On the other hand, when the small shaft 33 of the valve piston 18 comes into contact with the elastic piston 30 via the reaction piston 32 due to its advancement,
Due to the bulging deformation of the reaction piston 32 side of the elastic piston 30 due to the actuation reaction force of the output rod 34, a part of the reaction force is fed back to the brake pedal 98 side via the valve piston 18, so that the operator can output The output of the rod 34, that is, the braking force can be sensed.

Next, when the depression force on the brake pedal 98 is released, the reaction force applied to the valve piston 18 and the return spring 37 are
The input rod 17 retreats due to the elastic force, thereby seating the second valve seat 162 on the valve portion 2-3 and
is brought into contact with the front surface of the valve body holding cylinder 21, so that the valve portion 23 receives the retreating force of the input rod 17 and undergoes compressive deformation in the axial direction. As a result, a gap larger than the initial gap y is formed between the first valve seat 161 and the valve part 23, so that the air pressures in both the working chambers A and H quickly become balanced with each other through this large gap. When the pressure difference disappears, booster piston 5
moves backward by the elastic force of the return spring 12, and the protrusion 13 of the piston diaphragm 6 comes into contact with the inner surface of the rear wall of the boot shell 1 and stops. Then, when the input rod 17 comes into contact with the end wall 10, the valve part 23 is released from the retreating force of the input rod 17 and returns to its original shape, so that the gap with the first valve seat 16m is narrowed to the small gap 1 again. It can be fitted.

As described above, according to the present invention, the valve cylinder can be assembled to the booster piston extremely easily by the cooperation of the locking claw protruding from the booster piston and the locking plate. Since it can be commonly used in boosters having various output characteristics, economical efficiency can be improved.

Further, since the inner circumferential bead of the piston diaphragm is used to seal between the booster piston and the valve cylinder, a special sealing member is not required and the sealing structure can be simplified.

Furthermore, the valve cylinder's retaining flange and tapered surface strongly press the bulging part of the inner peripheral bead in the direction of the center line of the insertion hole and outward in the radial direction, ensuring a secure seal between the booster piston and the valve cylinder. be able to.

[Brief explanation of drawings]

1 to 7 show one embodiment of the present invention.
The figure is a longitudinal sectional front view of the whole, and corresponds to the case taken along the line I-I in Figure 2. Figure 2 is a side view showing the attachment relationship of the valve cylinder, locking plate, and seal mounting cylinder to the booster piston, and
The figure shows Boostapist 2.・-v L , + 71+
No, 2 I Park K1 Hat) - An exploded perspective view of the toy seal mounting cylinder, Figure 4 is a side view showing how to assemble the valve cylinder to the booster piston, and Figure 5 is a diagram showing how to assemble the valve cylinder to the booster piston. Fig. 6 is a perspective view showing the relationship between the seal mounting cylinder and tools, Fig. 7 is a cross-sectional view showing how the seal mounting cylinder is attached to the booster piston, and Fig. 8 is a partially enlarged vertical front view showing the seal structure. It is a partial side view of a modification which shows the relationship between a cylinder and a seal attachment cylinder. A, B... 1st. Second working chamber 1... booster shell, 5... booster piston,
6... Piston diaphragm, 8... Control valve, 14
... Valve cylinder, 41 ... Fitting hole, 43 ... Locking claw, 4
4... Cylindrical body, 45... Removal prevention flange, 46 Upper lever surface, 50... Locking plate, 58... Inner peripheral bead,
58a...Bulging portion patent applicant Nissin Kogyo Co., Ltd.

Claims (1)

[Claims] Boo, In the negative pressure booster, the booster piston is divided into the first working chamber or a second working chamber at the rear which can be alternately controlled to be communicated with the atmosphere through the booster piston, and the booster piston is provided with a valve cylinder for accommodating the control valve. A series of bulges protruding toward the first working chamber and inward of the fitting hole are provided on the annular inner peripheral bead of the piston diaphragm that is fitted to the opening edge of the valve cylinder fitting hole at the center of the booster piston, The valve barrel is configured with a retaining flange that is fitted into the fitting hole and is located on the first working chamber side, and the connecting portion of the main body with the retaining flange is tapered such that the retaining flange side has a larger diameter side. The retaining flange is clamped between the booster piston and a locking plate that forms a surface and is locked by a plurality of locking claws protruding from the first working chamber side of the booster piston. A negative pressure booster characterized in that the stop flange and the tapered surface press the bulging portion of the inner circumferential bead toward the center line direction and the radially outward direction of the insertion hole, respectively.