JPH0437018Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The present invention relates to a tandem negative pressure booster that boosts the brake master cylinder of an automobile with negative pressure. An open bottomed cylindrical front shell half, a rear shell half that closes the open end of the front shell half, and a shell sandwiched between the front and rear shell halves. A booster shell is constituted by a partition plate that divides a chamber between the two halves into a front shell chamber and a rear shell chamber, and the rear end of the front shell half has an annular step extending radially outward; a cylindrical portion extending rearward from the outer periphery of the bulkhead plate, and first and second flanges that overlap each other within the cylindrical portion and can rotate between a disassembled position and an assembled position, respectively on the bulkhead plate and the rear shell half. and a large number of notches are arranged circumferentially on the periphery of these flanges, and a positioning notch provided on the periphery of the second flange in order to match the notches of both flanges,
A projecting piece formed by cutting down a part of the first flange is penetrated and engaged with the cylindrical part, and when the both flanges are disassembled, the two flanges are inserted into the cylindrical part in alignment with the plurality of notches. A large number of locking claws are provided to enable fitting and removal, and to clamp both flanges to the stepped portion in the assembly position, and the outer peripheral bead of the front diaphragm is clamped between the front shell half and the partition plate; Further, a cylindrical portion of a partition plate continuous to the inner peripheral edge of the first flange;
This invention relates to an improvement in which the outer peripheral bead of the rear diaphragm is sandwiched between an annular locking protrusion that projects forward and radially outward from the inner peripheral edge of the second flange.

(2) Prior Art Such a tandem type negative pressure booster is already known, for example, as disclosed in Japanese Utility Model Application Publication No. 157361/1983.

Generally, in such a negative pressure booster, the state of engagement between the positioning notch on the rear shell half and the protruding piece on the bulkhead plate can be seen from the outside, so it is possible to see whether the phases of the first and second flanges match or mismatch with each other. can be determined immediately, which is convenient for assembly inspection.

(3) Problems to be solved by the invention By the way, the invention disclosed in the above publication extends the projecting piece of the rear shell half in the axial direction of the partition plate so that it is within the inscribed circle of the locking pawl group. Let me out, first, second
When both flanges are rotated to the assembly position, the protruding piece and the locking pawl are prevented from interfering with each other to prevent deformation of the protruding piece, but when the rear shell half and the partition plate are fitted together, There is a risk that the outer peripheral bead of the rear diaphragm, which is sandwiched between them, will be rubbed by the sharp tips of the protrusions and be damaged. In addition, when rotating both flanges toward the assembly position, it does not have a means to stop them at a predetermined assembly position, so it is easy to under-rotate or over-rotate both flanges, resulting in poor assembly performance. There are also problems.

The present invention was developed in view of the above circumstances, and when assembling the booster shell, the projecting piece of the bulkhead plate,
Not only can interference with the locking pawl of the front shell half be avoided, but also damage to the outer peripheral bead of the rear diaphragm caused by the protrusion can be prevented, and both flanges can be reliably stopped at a predetermined assembly position. It is an object of the present invention to provide the tandem type negative pressure booster as described above.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention forms the projecting piece so as to curve outward in the radial direction of the partition plate, while The second flange is characterized in that a stopper protrusion is formed on the second flange to stop both flanges at the assembly position by coming into contact with a predetermined locking pawl before the locking pawl interferes with the protrusion when rotating to the assembly position. do.

(2) Effect In the above configuration, when assembling the booster shell, when inserting the rear shell half into the cylindrical part of the bulkhead plate with the outer peripheral bead of the rear diaphragm in between, the protruding piece of the rear shell half will radially outward. Since it is curved, the tip will not rub against the outer peripheral bead.

Next, the projecting piece is penetrated into the positioning notch of the second flange to align the phases of the first flange and the second flange, and both flanges are fitted into the cylindrical part of the front shell half at the disassembled position. When the rear shell half is rotated relative to the front shell half to the assembly position, the first flange is simultaneously rotated from the second flange via the protrusion. Ru.

The locking pawl of the front shell half comes into contact with the stopper protrusion of the second flange before interfering with the protrusion, thereby ensuring that both flanges are stopped at a predetermined assembly position.

Therefore, even if the projecting piece protrudes outside the inscribed circle of the locking claw group due to radially outward warping,
Interference with the locking pawl is avoided, and deformation thereof can be prevented. In addition, as mentioned above, the warped protrusion crosses the second flange diagonally within the positioning notch, so even if the plate thickness of the protrusion and the second flange is relatively thin, the contact area between the two is relatively small. It can be obtained widely, and the surface pressure of the corresponding contact portion can be lowered when the first flange is rotated from the second flange.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a booster shell 1 of a tandem negative pressure booster B includes a pair of front and rear shell halves 1a, 1b whose opposing ends are connected to each other, and a pair of shell halves 1a, 1b which are sandwiched between both shell halves 1a, 1b. Half body 1a, 1
It is composed of a partition wall plate 1c that partitions the chamber between b into a front shell chamber 2 and a rear shell chamber 3. A brake master cylinder M is attached to the front surface of the front shell half 1a, and the rear shell half 1b is fixed to a vehicle body (not shown).

The front shell chamber 2 has a front booster piston 4 housed therein so as to be able to reciprocate back and forth, and is bonded to the rear surface thereof in an overlapping manner, and is sandwiched between the front shell half 1a and the partition wall plate 1c. The front diaphragm 5 divides the chamber into a front negative pressure chamber 2a on the front side and a front working chamber 2b on the rear side. Further, the rear shell chamber 3 has a rear booster piston 6 housed therein so as to be able to reciprocate back and forth, and a rear booster piston 6 which is overlapped and bonded to the rear surface and sandwiched between the two shell halves 1a and 1b together with the partition wall plate 1c. The diaphragm 7 divides the chamber into a rear negative pressure chamber 3a on the front side and a rear working chamber 3b on the rear side.

The front and rear booster pistons 4 and 6 are each formed into an annular shape from a steel plate, and are mounted at both front and rear ends of a synthetic resin piston boss 10 that is slidably supported on the partition plate 1c via a bush 8 and a seal member 9. Each is fixed. In this way, both booster pistons 4 and 6 are integrally connected to each other via the piston boss 10.

A valve cylinder 11 is integrally protruded from the rear end of the piston boss 10, and this valve cylinder 11 is connected to a rear extension cylinder 12 that protrudes from the rear wall of the booster shell 1 and covers the valve cylinder 11. It is slidably supported via a seal member 14.

The front negative pressure chamber 2a is connected to a negative pressure source (not shown) (for example, inside an intake manifold of an internal combustion engine) via a negative pressure introduction pipe 15, and is connected to a piston boss 1.
It communicates with the rear negative pressure chamber 3a through the first port 16 of No. 0. Further, both the front and rear working chambers 2b, 3b communicate with each other via the second port 17 of the piston boss 10, and a control valve 18 provided in the valve cylinder 11
This allows communication to be alternately switched between the front and rear negative pressure chambers 2a, 3a and an air inlet 19 opened in the end wall of the rear extension cylinder 12. The control valve 18 is connected to a brake pedal 21 via an input rod 20.
This is a known method operated by.

Further, an output rod 23 is attached to the piston boss 10, which protrudes forward and is connected to the rear end of the piston 22 of the master cylinder M, and is connected to the front negative pressure chamber 2a.
A return spring 24 that urges the piston boss 10 in the backward direction is contracted therein.

When the input rod 20 is moved forward by depressing the brake pedal 21, the working chambers 2b and 3b are moved forward.
is disconnected from the negative pressure chambers 2a, 3a by the control valve 18 and communicated with the atmosphere inlet 19, so that atmospheric pressure acts on the working chambers 2b, 3b, and the negative pressure chambers 2a, 3a and the working chambers 2b and 3b, the booster pistons 4 and 6 move forward, and the piston 22 of the master cylinder M can be boosted via the output rod 23. Furthermore, when the brake pedal 21 is released and the input rod 20 is moved backward, the working chambers 2b and 3b are moved to the control valve 18.
The working chamber 2 is disconnected from the atmosphere inlet 19 and communicated with the negative pressure chambers 2a and 3a.
The pressure difference between b, 3b and negative pressure chambers 2a, 3a decreases, and the force of the return spring 24 causes the booster pistons 4,
6 can retreat.

Now, the three-way joint structure of the front and rear shell halves 1a, 1b and the partition plate 1c will be explained.

The front shell half 1a has a bottomed cylindrical shape with an open rear end, and has first, second, and annular rings extending radially outward at its center, rear intermediate portion, and rear end, respectively. Three step portions 25, 26, and 27, and first, second, and third cylindrical portions 28, 29, and 30 extending rearward from each outer circumferential end of these step portions are formed, and the rearward of these cylindrical portions, It has a large diameter.

The partition wall plate 1c includes annular fourth and fifth step portions 32 and 33 that respectively oppose the first and second step portions 25 and 26 within the front half shell 1a, and the third step portion 27. a first flange 34 in contact with the first flange 34;
a fifth which fits into the second cylindrical portions 28 and 29 respectively;
Sixth cylindrical portions 35 and 36 are formed.

Furthermore, a locking projection 38 is bent and formed on the partition wall plate 1c, and projects diagonally forward from the inner circumferential edge of the fourth step 32 to define an annular groove 37 between the fourth step 32 and the fourth step 32. The tip of 38 is the first step portion 25
They face each other with a certain gap between them. Thus, the outer peripheral bead 5a of the front diaphragm 5 is fitted into the annular groove 37, and its root portion is held between the first step portion 25 and the locking protrusion 38.

The fifth step portion 33 is close to the second step portion 26 to the extent that it does not touch the second step portion 26 .

On the other hand, the rear shell half 1b has a dish shape with an open front end, and has a second flange 39 overlapping the rear surface of the first flange 34 at the front end, and a diagonally forward direction from the periphery of the second flange 39. A locking protrusion 41 that protrudes to define an annular groove 40 between the second flange 39 and the second flange 39 is formed.
The tip faces the fifth step portion 33 with a certain gap therebetween. Thus, the outer peripheral bead 7a of the rear diaphragm 7 is fitted into the annular groove 40, and its root portion is held between the fifth step portion 33 and the locking protrusion 41.

In addition, as shown in FIGS. 2 and 5, the third
A large number of locking claws 42 ₁ , 42 ₂ . . . 42 _o are formed on the cylindrical portion 27 at equal intervals in the circumferential direction by cutting and bending inward in the radial direction, and these locking claws are connected to the second By engaging with the rear surface of the flange 39, the first
Both second flanges 34 and 39 can be clamped to the third step portion 27. Both flanges 3 at this time
The position No. 4, 39 is called assembly position A.

On the other hand, the first and second flanges 3 overlapped with each other.
4, 39, the above-mentioned locking claws 42 ₁ , 42 ₂ . . . 42
The same number of _notches 43 ₁ ,
43 ₂ ... 43 _o , 44 ₁ , 44 ₂ ... 44 _o are provided, respectively. As shown in FIG. 3, these notches 43 ₁ , 43 ₂ ... 43 _o , 44 ₁ , 44 ₂ ... 4
When the phases of 4 _o and the locking claws 42 ₁ , 42 ₂ ... 42 _o match, the locking claws 42 ₁ , 42 ₂ ... 42 _o have notches 43 ₁ , 43 ₂ ... 43 _o , 44 ₁ , 44 ₂ ...44 _o
can pass through. The position of both flanges 34 and 39 at this time is called disassembly position D.

Also, as shown in Figures 2, 6 and 7,
When the second flange 39 occupies the assembly position A, a positioning notch 45 is provided between adjacent locking claws 42 ₁ and notches 43 ₁ , and a protrusion that penetrates and engages with this positioning notch 45 is provided in the second flange 39. 46 is connected to the rear end of the sixth cylindrical portion 36. At this time, the protruding piece 46 is formed by cutting down the first flange 34. These positioning notches 45 and protrusions 46 engage with each other to constitute positioning means 47.
Phase matching of 3 ₁ , 43 ₂ . . . 43 _o , 44 ₁ , 44 ₂ . . . 44 _o can be obtained.

The protruding piece 46 is curved so as to move radially outward toward the rear.

Furthermore, as shown in FIGS. 2, 8, and 9, first and second stopper projections 49, 50 are formed on the second flange 39. First stopper protrusion 4
9 comes into contact with a predetermined locking pawl 42 ₁ at the assembly position A of the second flange 39 to prevent the second flange 39 from rotating more than necessary, and in order to ensure this prevention, the side wall of the protrusion 49 stands upright from the rear surface of the second flange 49.

On the other hand, the second stopper protrusion 50 comes into contact with a locking claw 42 ₂ that is different from the predetermined locking claw 42 ₁ at the assembly position A of the second flange 39 and rotates the second flange 39 to the disassembly position D. However, when a load of a certain value or more is applied from the locking claw 42 ₂ , the side wall is rounded to allow the locking claw 42 ₂ to pass through.

Next, to explain the operation of this embodiment, when assembling the booster shell 1, first, the outer circumferential bead 7a of the rear diaphragm 7 is attached to the partition plate 1c in which the outer circumferential bead 5a of the front diaphragm 5 is attached to the annular groove 37. The rear shell half 1b attached to the groove 40 is fitted, and the protrusion 46 is inserted into the positioning notch 45.
The first and second flanges 34, 3
9 is polymerized.

In this case, the protruding piece 46 is inclined as described above, and its tip is spaced apart from the outer peripheral bead 7a of the rear diaphragm 7, so that the outer peripheral bead 7a is damaged by the tip of the protruding piece 46 during the above-mentioned fitting. Never.

Next, as shown in FIG. 3, the notches 43 ₁ , 43 ₂ . . . 43 _o , 44
₁ , 44 ₂ ... 44 _o with the locking claw 42 ₁ , 42 ₂ ... 42
The partition plate 1c and the rear shell half 1b are fitted into the front shell half 1a at the disassembled position _D , which is aligned with the position D. Then, the first flange 34 is attached to the front shell half 1.
The rear half shell 1b is rotated relative to the front shell half 1a in the direction of arrow R in FIG. 7, that is, toward the assembly position A, while being brought into contact with the third step 27 of FIG. At this time, the partition plate 1c rotates integrally with the rear shell half 1b because the protruding piece 46 is engaged with the positioning notch 45 of the second flange 39. In this case, since the protrusion 46 diagonally crosses the second flange 39 within the positioning notch 45, even if the protrusion 46 and the second flange 39 are thin,
Their contact area is relatively large, so the surface pressure during the rotation can be reduced.

With the rotation of the rear half shell 1b in the R direction,
When the locking pawl 42 ₂ approaching the second stopper projection 50 passes over the second stopper projection 50 and the rear shell half 1b reaches the assembly position A, the other locking pawl 42
₁ immediately comes into contact with the first stopper protrusion 49 and prevents the rear half shell 1b from rotating more than necessary, so that the locking pawl 42 that has climbed over the second stopper protrusion 50
₂ does not come into contact with the protruding piece 46 of the positioning means 47.

Thus, the first and second stopper projections 49, 50
can hold the assembly position A of both shell halves 1a, 1b by sandwiching a plurality of locking claws 42 ₁ , 42 ₂ between them, and therefore all the locking claws 42 1 , 42 ₂ can be held in the assembled position A.
42 ₂ ... 42 _o makes the first and second flanges 34,
39 can be reliably clamped to the third step portion 27.

Further, even after assembly, the engaged state of the positioning notch 45 and the protruding piece 46 can be seen from the rear of the rear half shell 1b.
It is possible to determine whether the 37 phases match or do not match.

The procedure for disassembling the booster shell 1 is to perform the above operations in reverse. In this case, the locking claw 42 ₂
is slightly deformed by climbing over the second stopper protrusion 50 again, but the other locking pawl ₄₂₁ facing the first stopper protrusion 49 is not deformed.
Even during reassembly, the rear shell half 1b can be reliably stopped at the predetermined assembly position A by the contact between the locking pawl 42 ₁ and the first stopper protrusion 49.

Note that during assembly at the production factory, the locking claws 42 ₁ , 4 are attached to the third cylindrical portion 30 of the front shell half 1a.
2 ₂ ...42 _o Before forming the front shell half 1a, the partition plate 1c and the rear shell half 1b are fitted, and then, as shown in FIG. 42 ₁ , 42 ₂ ... 42 _o may be formed.

C. Effects of the invention As described above, according to the invention, damage to the outer peripheral bead of the rear diaphragm caused by the positioning protrusion between the first and second flanges can be prevented during assembly of the booster shell.

Furthermore, when both flanges are rotated to the assembly position, even if the protruding piece protrudes outside the inscribed circle of the locking pawl group of the front shell half, the protruding piece and the locking pawl are not engaged before they interfere with each other. Since both flanges can be reliably stopped at the predetermined assembly position by the contact between the retaining pawl and the stopper protrusion of the second flange, deformation of the protruding piece is prevented and the ease of assembly is extremely good. .

Furthermore, even if the plate thickness of the protruding piece and the second flange is thin, the contact area between them is relatively wide due to their diagonal intersection, and as a result, the surface pressure of these contact parts is reduced, and the durability is improved. can bring about improvement.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a longitudinal cross-sectional side view of a tandem negative pressure booster, Fig. 2 is a view taken in the direction of the arrows in Fig. 1, and Fig. 3 is a diagram showing Fig. 2 before assembly. The corresponding explanatory drawings, FIG. 4, FIG. 5, and FIG. 6 are sectional views taken along lines -, -, and - of FIG.
7 is a cross-sectional view taken along the line -- in FIG. 6, and FIGS. 8 and 9 are cross-sectional views taken along the line -- and -- in FIG. 2. B...Negative pressure booster, 1...Booster shell,
1a, 1b...Front and rear shell halves, 1c...Partition plate, 2...Front shell chamber, 3...Rear shell chamber, 7...Rear diaphragm, 7a...Outer periphery bead, 27...Step part , 30... Cylindrical portion of front shell half, 34, 39... First and second flanges, 36
... Cylindrical part of bulkhead plate, 42 ₁ to 42 _o ... Locking claw,
43 ₁ ~ 43 _o ... Notch of first flange, 44 ₁ ~
44 _o ...Notch of second flange, 45... Positioning notch, 46... Protrusion piece, 49... Stopper protrusion.

Claims (1)

[Claims for Utility Model Registration] A bottomed cylindrical front shell half with an open rear end;
A rear shell half that closes the open end of the front shell half is sandwiched between the front and rear shell halves to divide the chamber between the two shell halves into a front shell chamber and a rear shell chamber. A booster shell is formed from a bulkhead plate, and the rear end of the front shell half has an annular step extending radially outward, and a cylindrical portion extending rearward from the outer periphery of the step. First and second flanges that overlap each other within the cylindrical portion and can rotate between a disassembled position and an assembled position are provided on the bulkhead plate and rear shell half, respectively, and a number of notches are formed in the circumferential direction on the periphery of these flanges. A projection piece formed by cutting down a part of the first flange is penetrated and engaged with a positioning notch provided on the periphery of the second flange so that the notches of both flanges coincide with each other, and the cylindrical part In the disassembled position of both flanges, there are a number of locks that coincide with the plurality of notches to enable fitting and detachment of both flanges to and from the cylindrical part, and in an assembled position, a number of locks that clamp both flanges to the step part. A retaining pawl is provided, the outer peripheral bead of the front diaphragm is sandwiched between the front shell half and the partition plate, and the cylindrical portion of the partition plate continues to the inner peripheral edge of the first flange, and the inner peripheral edge of the second flange. In a tandem negative pressure booster in which the outer circumferential bead of the rear diaphragm is sandwiched between an annular locking protrusion that protrudes forward and radially outward from the partition plate, the protrusion is bent radially outward of the bulkhead plate. and a stopper projection that abuts a predetermined locking pawl to stop both flanges at the assembly position before the locking pawl interferes with the protrusion when the flanges are rotated to the assembly position. A tandem negative pressure booster, characterized in that a second flange is formed with a second flange.