JPS6067250A - Negative-pressure type booster - Google Patents

Abstract

PURPOSE:To simplify the turn preventing structure by preventing the relative turn between a valve cylinder and an expandable boot which covers a tie rod by a turn preventing means which is installed between the valve cylinder and the expandable boot and fitted in the mutual correspondence in uneven parts. CONSTITUTION:A seal installation cylinder 83 for the installation of an expandable boot is installed in sealed state onto a piston 5, allowing each opened edge of the through hole 79 of a booster piston 5 and the through hole of a piston diaphragm between the locking hook 84 and the flange 86. While, a cut part 92 having an arcuate concaved inner peripheral surface which conforms to the outer peripheral surface between the contiguous locking hooks 84 on the seal installation cylinder 83 is formed onto a flange 45 for preventing the slip-off of a valve cylinder 14. Therefore, the outer peripheral surface in the vicinity of the both edges of the cut part 92 on the flange 54 for preventing the slip-off of the valve cylinder 14 is engaged with the side surface 84 of the contiguous locking hook 84 on assembly, and the relative turn between the valve cylinder 14 and the seal installation cylinder 83 is prevented.

Description

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

Conventionally, as this latch device, a booster tank consisting of a pair of front and rear bowl-shaped bodies is connected to a first working chamber at the front which is constantly connected to a negative pressure source by a booster piston that can reciprocate back and forth, and a control valve. The booster piston is divided into a first working chamber and a second working chamber at the rear which is alternately controlled to be communicated with the atmosphere, and the booster piston is provided with a valve part that houses the entire control valve, and a tie rod that passes through the keboostaviston between both bowl-shaped bodies. It is known that the booster piston and the tie rod are connected by a sealing means for sealing the tie rod through hole of the booster piston.

If the two arm-like bodies are connected by a tie rod as described above, the reinforcement effect of the tie rod will allow the booster/el to be molded from a lightweight material, such as a thin steel plate or synthetic resin, thereby reducing the weight of the device. can be achieved.

By the way, in the above device, if the valve cylinder is completely assembled to the booster piston, when manufacturing products with various output characteristics, the booster piston can be changed and the valve cylinder can be used in common, which is economical. However, conventionally, the booster piston and the valve barrel are integrally molded from synthetic resin, so the above effects cannot be obtained.

In view of the above, the present invention improves economic efficiency by configuring the booster piston and the valve cylinder separately so that the valve cylinder can be used in common when manufacturing a booster having various output characteristics. It is an object of the present invention to provide the entire booster device in which the rotation prevention structure for the booster piston of the valve cylinder can be completely simplified, and the booster piston has a fitting hole for the valve cylinder located at the center thereof and a periphery of the fitting hole. A through hole for passing through the tie rod is provided at the position, a valve cylinder is fitted into the insertion hole, a 1/7-hole mounting cylinder is fitted into the through hole and provided on the booster piston,
It is characterized in that a rotation preventing means is provided between the valve cylinder and the 7-hole mounting cylinder to prevent them from rotating by fitting concavely and concavely between the valve cylinder and the 7-hole mounting cylinder, and a sealing means is provided between the 7-hole mounting cylinder and the tie rod.

An embodiment in which the present invention is applied to a brake master/ring will be described below with reference to the drawings.

In FIG. 1, booster shell 1 of negative pressure booster S
consists of a pair of front and rear bowl-shaped bodies 1F and 1R molded from a lightweight thin-walled steel plate or synthetic resin, and a plurality of claw pieces 2 protruding from the openings of the rear bowl-shaped bodies 1R at equal intervals on the circumference. , both arm-shaped bodies 1F and 1R are mutually positioned by engaging with a plurality of notches 3 formed at equal intervals on the circumference in the opening of the front bowl-shaped body 1F, and both arm-shaped bodies 1F , 1R, the front and rear opposing walls are connected via a pair of tie rods 4. The connection structure between the booster/well 1 and the tie rod 4 will be described later. The tire diaphragm 6 separates a first working chamber A at the front and a second working chamber B and V at the rear.

The first working chamber Ail''J: is constantly connected to the intake manifold (not shown) of the internal combustion engine, which is a negative pressure source, through the negative pressure introduction pipe 7, and the second working chamber B is connected through the control valve 8, which will be described later. First
Communication is alternately controlled to the working chamber A or the atmosphere inlet 11 opened in the end wall 1o of the rear extension tube 9 of the booster nonyl 1.

The booster piston 5Vi is always urged in the backward direction, that is, in the second working chamber B side, by the return spring 12 contracted in the first working chamber A, and its backward limit is reached by a protrusion 13 formed protrudingly formed on the back surface of the piston diaphragm 3. It is regulated by coming into contact with the inner surface of the rear wall of the shell 1.

The booster piston 5 is provided with a valve cylinder 14 that protrudes rearward from its center.The valve cylinder 14 is slidably supported on a flat bearing 15 provided on the extension cylinder 9, and its rear end It is opened toward the atmosphere inlet 11.

The control valve 8 is configured in the valve cylinder 14 as follows. That is, an annular first valve seat 16□ is formed on the inner wall of the front part of the valve cylinder 14, and a valve piston/18 that is connected to the man lever 17 and forms the front end thereof is formed in the front part of the valve cylinder 14. The rear end of the valve piston 18 is fitted with the first valve seat 16. 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 clamped onto 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 is connected to the first and second valve seats 16. ．． Facing 162. 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 this cleverly connects the valve portion 23 to both valve seats 16. ．． Valve spring 25 is connected to bias toward 162 .

First valve seat 16. The outer part of the booster piston 5 is connected to the first working chamber A through a pair of through holes 26, and to the first and second working chambers A.
Valve seat 16. ．． The middle part of the valve 162 is in constant 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 VC, and a small-diameter 7-ring hole 29 that opens at the inner end of the cylinder hole 28. An elastic piston 3o made of rubber or the like and an output piston 31 having the same diameter as the elastic piston 3o are inserted into the hole 28 from the back thereof.
The elastic piston 30 and the reaction piston 32 of a smaller diameter are slid into the small diameter cylinder hole 29 one after another. A small shaft 33 protruding from the front end surface of the valve piston/18 enters the cylinder hole 29 having a relatively small diameter, and the reaction piston/32
Opposed to the rear end surface of. An output rod 34 is protruded from the front surface of the extractor piston 31, and the output rod 34 is disposed in the first working chamber A.

The input rod 1T is always pushed 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. It is regulated by

When the movable stopper plate 35 is fully rotated, the screwing position between it 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 air inlet 11 will not be blocked.

Filters 39 and 40 that can be deformed so as not to come off the atmosphere inlet 11 are attached to the outer end opening of the valve barrel 14 .

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. '-i: The booster piston 5 has a fitting hole 41ff.
i A pair of arc-shaped reinforcing ribs 42 that are arranged so as to surround each other and protrude from the front surface 5a, and a pair of locking ribs on the outside of both reinforcing ribs 42 that are cut up toward the front surface 5a with their tips facing each other. A claw 43 is provided. 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 cylindrical body 45. is a tapered surface 46 whose flange 45 side is the larger diameter side.
is formed. The retaining flange 45 has the large-diameter cylinder hole 28 on its end face, and a truncated conical short cylindrical portion 47 concentric with the main body 44, and the short cylindrical portion 47'f! : It has a pair of protrusions 49 having flat top surfaces 48 arranged so as to be sandwiched therebetween, and the one through hole 26 is opened in 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 that can be loosely fitted into the short cylinder part 47', 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 thereof, and a pair of locking parts 54 extend further outward from both ends of both leg parts 530. 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 54 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 tube part 47, and the connecting part between the flat plate part 52 and the leg part 53 is closed at a position where it is removed from the locking claw 43. Align the outer circumferential edge of the retaining flange 45 and the connecting portion between the leg portion 53 and the locking portion 54 with the outer circumferential edge of the reinforcing lip 42, and from this state, connect the locking plate 50 with the leg portion 53 and the locking portion. When the connecting portion with the reinforcing lip 42 is brought into contact with the reinforcing lip 42 and rotated in the direction of the arrow a 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.
0 rides on the top surface 48, and as a result, the retaining flange 45 is caught between the locking plate 50 and the booster piston 5, and the valve cylinder 1
4 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. The movable end of the return spring 12 engages with the cap portion 51 of the locking plate 50, and the elastic force of the return spring causes the locking plate to be inserted 500 times without being stopped. 3
Since the diameter is smaller than that of No. 1, the cap top wall 51a surrounding the through hole 56 faces the opening of the cylinder hole 28 and functions as a stopper piece facing the output piston 31, so that when the booster piston 5 is assembled, the output Viston 31
Also, problems such as the output rod 34 falling from the valve cylinder 14 will not occur.

As shown in FIGS. 1 and 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 60f protruding from its end surface. It is fitted into each positioning hole 61 formed on the outer periphery of the rear bowl-shaped body 1R and sandwiched between both arm-shaped 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 in a free state, the inner peripheral bead 58 has a front surface 5a of the booster piston 5 as shown by the chain line in FIG.
A series of bulges 58a that protrude inward from the sides and the insertion hole 41
is formed. When the retaining flange 45 of the valve cylinder 14 is clamped between the locking plate 5o and the booster piston 5 as described above, the retaining flange 45 is located at the center of the insertion hole 41 as shown by the arrow. It is strongly pressed in the linear direction and radially outward of the fitting hole 41 as shown by arrow C by the tapered surface 46 of the valve cylinder 14, and is compressed into the annular recess 62 around the fitting hole 41, thereby causing the valve to close. The space between the cylinder 14 and the booster piston 5 is reliably sealed.

The pressure receiving portion 63 of the piston/diaphragm 6 is in close contact with the rear surface of the booster histone 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. The booster piston 5 is bent into a U-shape, and the booster piston 5 is allowed to move forward and backward by shifting the U-shaped bent portion.

As shown in FIGS. 1 and 5, an opening 64 is formed in the part of the booster piston 5 where the locking claw 43 is completely cut out, and the connection between the booster piston 5 and the piston diaphragm 6 is formed through the opening 64. Since it communicates with the first working chamber A, no air pockets occur between the two. Further, the portion of the piston diamond 7 ram 6 facing the opening 64 is formed into a thick wall portion 65, which allows air to be introduced into the second working chamber BVc so that the air pressure in the second working chamber B is changed to the first working chamber B. Even if the height is higher than that of the working chamber A, the thick portion 65 will not bulge into the opening 64, and therefore damage caused by the opening 64 of the piston diaphragm 6 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 7L 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 1, and the enclosure of the mounting flange 68 are integrally connected. At that time, bolt 66
An annular seal member 71 for sealing 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 spring receiving plate 67 . The spring receiving plate 67 supports the fixed end of the return spring 12,
The entire elastic force of the return spring 12 is borne by the tie rod 4, and the load on the booster shell 1 can be removed.

a mounting port (72) penetrating the rear wall and protruding rearward therefrom;
Stepped flange 7 that comes into contact with the inner surface of the rear wall of booster shell 1
3 are integrally formed. The step flange 73 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, so that the tie rod 4 and the rear wall of the booster shell 1 are connected to each other. connected together. At this time, the annular seal member 71 that seals the annular groove 76VC between the small diameter portion of the stepped flange γ3 and the support tube 74 and the tie rod through hole in the rear wall of the booster shell 1 is completely fitted.

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 WVc of the single compartment by screwing and tightening the nut γ8 to the tip thereof.

In this way, the booster shell 1 is attached to the front wall WVc of the vehicle interior through the entire tie rod 4, and the brake muff) 2 ・N II ・i JourrF A 7r+ -7L' A
&itel ``'rm''y Connected to J/el1.

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

As shown in FIGS. 1 and 3, the booster piston 5 has a pair of tie rod penetration holes 79 formed between the reinforcing ribs 42, and a plurality of through holes 79, three in the illustrated example, are formed on the rim of the booster piston 5. Notches 80 are provided at equal intervals on the circumference. Further, the piston diaphragm 6 also has a through hole 81 corresponding to the through hole 79.
A thick portion 82 is formed at the edge of each through hole 81.

As shown in FIGS. 3 and 6, three locking claws 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 locking claws 84 are provided at the other end. A retaining flange 86 having a tool engaging recess 85 is provided in a protruding manner. The top surface 84aK of each locking pawl 84 is formed with a fitting guide inclined surface 84b that slopes downward from the intermediate portion toward the end surface of the seal mounting tube 83, and the rising surface 84c is formed from the intermediate portion to one end. A rotation guiding inclined surface 84d having a downward slope is formed. The direction of inclination of the rotation guiding inclined surface 84d in each locking pawl 84 is the same.

The attachment of each 7-ring attachment tube 83 to the booster piston 5 is performed before the valve tube 14 is attached to the booster piston 5, and the seal attachment tube 83 is attached to each locking tube from the rear surface 5b side of the booster piston 5. The claws 84 are aligned with each notch 80 and inserted into the through holes 81.79 of the piston diaphragm 6 and the booster piston 5. In this case, the through-hole 7 of the booster piston 5 of the seal mounting cylinder 83 is formed by the fitting guide inclined surface 84b of the top surface 84a of each locking claw 84.
9 can be inserted smoothly. Then, as shown in FIGS. 6 and 7, the short cylindrical portion 88 of the tool 87 is inserted into the seal mounting tube 83, and each engagement protrusion 89 on the outer peripheral surface of the short cylindrical portion 88 is inserted into each tool engagement recess 85. Then, by pressing the tool 87 against the front surface 5a of the booster piston 5, the nondle 91 is rotated in the direction of the arrow d in FIG. 7 while the thick portion 82 of the booster piston 5 is fully compressed. As a result, each locking pawl 84 is misaligned with each notch 80.
The through hole 79 of the booster piston 5 and the piston diaphragm 6 is between the rising surface 84c of the booster piston 5 and the retaining flange 86.
The edge 810 is clamped, and the space between the booster piston 5 and the seal mounting cylinder 83 is sealed. In this case, each locking pawl 84 smoothly enters the edge of the through hole 790 of the booster piston 5 due to the rotation guiding inclined surface 84d of the rising surface 84c of each locking pawl 84, and the aforementioned clamping is performed reliably.

As shown in FIGS. 2 and 3, the retaining flange 4 of the valve cylinder 14
5, phase 11M-y in both seal mounting tubes 83
IH ■ I II J *a n\hJ IJ+1-;
A notch 92 having a circumferential surface is formed, and the valve cylinder 14 is formed as described above.
When inserted into the insertion hole 41 of the booster piston 5 and fully fitted with each notch 92 and each seal mounting tube 83, the outer peripheral surfaces near both ends of each notch 92 in the retaining flange 45 are locked adjacent to each other. It engages with the side surface 84e of the pawl 84, thereby preventing the valve cylinder 14 and the seal mounting cylinder 83 from rotating relative to each other. As another rotation preventing means, as shown in FIG. 8, a recessed groove 93 capable of engaging with one locking pawl 84 may be entirely 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 permit operation of the booster piston 5. The sealing means is composed of a bellows-shaped telescopic boot 94 made of an elastic material such as rubber. , and the rear ends 94b are fitted into the openings of the seal mounting tube 83, respectively.

In the single chamber, at the rear end of the input rod 17 of the booster S, there is a brake pedal 98 that is pivoted 9γ on a fixed bracket 96.
are connected via a connecting fitting 99. 100 is a return spring that biases the brake pedal 98 rearward.

The rear end of the cylinder body 101 of the brake mask cylinder M penetrates the front wall of the booster shell 1 and protrudes into the first working chamber A, and a booster S is installed at the rear end of the working piston 102 in the cylinder body 101. The output rods 34 of the two are opposed to each other.

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 and pushes it against the valve body holding cylinder 21. It is moved back until it makes light contact with the front surface, thereby forming a slight gap gk between the first valve seat 16 and the valve seat 23. Such a state can be easily obtained by adjusting the movable stopper 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 g, and the through hole 2γ, and the front opening of the reduced valve portion 23 Since the second working chamber BK is closed by the second valve seat 16□, the negative pressure of the first working chamber A is transmitted to the second working chamber BK, and the air pressures of both working chambers A and B 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 fully advanced, the valve portion 23 urged forward by the valve spring 25 moves forward following the valve piston 18, but the first valve seat 16. and valve part 23
As mentioned above, the gap g between the valve part 23 and the first valve seat 161 is extremely narrow, so the valve part 23 immediately seats on the first valve seat 161 to cut off the communication between the two working chambers A and B, and at the same time, the second valve seat 1°6□ is separated from the valve portion 23 and communicates with the atmosphere inlet 11 via the second working chamber Bi through hole 27 and the inside of the valve body 19. Therefore, the atmosphere is quickly introduced into the second working chamber B, and the second working chamber B is replaced by the first working chamber A.
The booster piston 5 moves forward against the return spring 12 due to the pressure difference generated between the compartments A and B, and moves the output rod 34 forward through the entire elastic piston 30, so that the operating piston 102 of the brake mask cylinder M It drives all the way forward and brakes are applied to the vehicle.

When the operating piston 102 is driven, the cylinder body 10
A forward thrust load is applied to the vehicle body 1, and this load is transmitted to and supported by the vehicle body, that is, the single-chamber front wall W, via the tie rod 4. Therefore, the above 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, the elastic piston 30 bulges and deforms toward the reaction piston 32 side due to the operational reaction force of the output rod 34. A portion of the reaction force is fed back to the brake pedal 98 side via the valve piston 18, so that the driver can sense the entire output of the output rod 34, that is, the entire braking force.

Next, when the depression force of the brake pedal 98 is released, the valve piston 18 & the above-mentioned reaction force and the return spring 3
The input rod 17 retreats due to the elastic force of the second
The valve seat 162 is seated on the entire valve portion 23 and the valve portion 23
is brought into contact with the front surface of the valve element holding cylinder 21, so that the valve part 23 receives the retreating force of the input rod 17 and is compressively deformed in the axial direction. As a result, a gap larger than the initial gap g is formed between the first valve seat 1°61 and the valve part 23, so that the air pressures in both working chambers A and B are quickly balanced with each other through this large gap. When the pressure difference between them disappears, the booster piston 511-1 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 booster shell 1 and stops.

When the input rod 17 comes into contact with the end wall 10, the valve part 2
3 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 161 can again be inserted into the small gap g.

As described above, according to the present invention, the valve cylinder can be commonly used in boosters having various output characteristics, so that economical efficiency can be improved. In addition, it is possible to machine an annular groove or an annular protrusion for attaching the sealing means to the seal mounting tube, so even if the booster piston is made of a thin steel plate, it is possible to securely attach the sealing means to the booster piston through the seal receiving tube. It can be taken to Furthermore, since the valve cylinder and the seal mounting cylinder are mutually prevented from rotating by a rotation prevention means that is provided between them and engages in a concave and convex manner, the rotation prevention structure is simpler than when each cylinder is individually prevented from rotating. can be simplified,
Further, it is possible to prevent the occurrence of detachment or loosening of various parts due to rotation of the valve cylinder and the seal mounting cylinder.

[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 1-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 Figure 3
The diagram shows the booster piston, piston diaphragm, valve cylinder,
An exploded perspective view of the locking plate and the seal mounting cylinder, Fig. 4 is a side view showing how the valve cylinder is assembled to the booster piston, and Fig. 5 is a partially enlarged longitudinal sectional front view showing the seal structure of the booster piston and the valve cylinder. , Fig. 6 is a perspective view showing the relationship between the seal mounting cylinder and tools, Fig. 7 is a sectional view showing how the seal mounting cylinder is attached to the booster piston, and Fig. 8 is a valve cylinder and seal installation of another embodiment. FIG. 3 is a partial side view showing the relationship between cylinders. A, B...first and second working chambers, -1...booster shell, IF, IR...bowl-shaped body,
4...Tie rod, butt...Booster piston, 8...
・Control valve, 14... Valve cylinder, 41... Fitting hole, 79.
...Through hole, 83...Seal mounting tube, 84,92.93
...Latching pawl, notch, and groove constituting rotation stopping means, 94... Telescopic boot as sealing means.

Claims (1)

[Claims] Inside the booster shell, which is made up of a pair of front and rear bowl-shaped bodies, a first working chamber at the front part is constantly communicated with a negative pressure source by a booster piston that can freely reciprocate back and forth, and the first working chamber or The booster piston is divided into a second working chamber at the rear which is alternately controlled to be communicated with the atmosphere, and the booster piston is provided with a valve cylinder that accommodates the control valve in all stages, and a tie rod that passes through the entire booster piston between both arm-like bodies. In the negative pressure booster, the booster piston is connected to the tie rod, and the booster piston is provided with a sole means for sealing the tie rod penetration hole t'' of the booster piston between the booster piston and the tie rod.
Fitting hole for valve cylinder located in the center of it J-#m completed 1/7
- 1. A through hole is provided for passing through the valve cylinder, and a seal receiving cylinder is fitted into the through hole, respectively, and the booster is inserted into the through hole. A rotation preventing means is provided on the piston and fits between the valve cylinder and the sol mounting cylinder to prevent them from rotating, and the sealing means is provided between the seal mounting cylinder and the tie rod. A negative formal booster.