JP6046507B2 - Negative pressure booster - Google Patents

Description

The present invention relates to a negative pressure booster used for boosting a brake master cylinder of an automobile, and in particular, a saddle-shaped front shell half and a rear end of the front shell half sandwiching a diaphragm. A saddle-shaped rear shell half whose front ends are opposed to each other, and a tie rod that passes through the front and rear shell halves in an axial direction and connects them to each other. The tie rod includes a rear shell half an airtight coupling portion that is coupled hermetically to the body, through holes respectively provided a fastening receiving portion for supporting the rear face the front shell half, front section half shells and the mounting flange of the master cylinder to be overlaid on the front face A negative pressure booster in which a nut for fastening between a front shell half and the mounting flange is screwed to the bolt portion in cooperation with the fastening receiving portion.

  Such a negative pressure booster is already known as disclosed in Patent Document 1.

Japanese Patent No. 4638054

  In the negative pressure booster described in Patent Document 1, the fastening receiving portion for supporting the rear surface of the front shell half is composed of a nut screwed to the tie rod, so the front and rear shell halves are connected by the tie rod. In order to ensure the hermeticity of the booster shell, the screwing position of the nut is adjusted, and the distance between the nut and the hermetic joint connected to the rear shell half is set as specified. Therefore, the number of parts is large and the assembly work is troublesome.

The present invention has been made in view of such circumstances, and a fastening receiving portion for supporting the rear surface of the front shell half is integrally formed with the tie rod, so that it is not necessary to adjust the screwing position of the nut as in the prior art. In this way, it is easy to connect the front and rear shell halves with the tie rods and to attach the master cylinder. Even if the fastening receiving part is formed integrally with the tie rod, the fastening receiving part and the mounting flange of the master cylinder It is an object of the present invention to provide the negative pressure booster capable of reliably sealing the through hole of the front shell half through which the tie rod penetrates while securing the fastening axial force between the tie rod and the tie rod.

In order to achieve the above object, the present invention comprises a bowl-shaped front shell half, and a bowl-shaped rear shell half with a front end opposed to the rear end of the front shell half. A tie rod that passes through the front and rear shell halves in an axial direction and interconnects the tie rods, the tie rods including an airtight coupling that is airtightly coupled to the rear shell halves, a fastening receiving portion for supporting the rear surface of the part shell half, front section half shells and provided with a front bolt extending through a respective hole provided in the mounting flange of the master cylinder to be overlaid on the front end surface, the engagement in the negative pressure booster of the receiving part in cooperation with a nut for fastening between the front shell half and the mounting flange screwed to the front bolt portion, integrally formed a front flange to a tie rod as the fastening receptacle The surface facing the front portion shell halves before Symbol mounting flange, surrounds the mounting flange peripheral surface and at is defined in a triangular cross tie rod tapered surface and the tie rod which is formed on the rear edge of the hole of An annular seal groove is formed, and an O-ring that is in close contact with the front shell half is attached to the seal groove, and the O-ring is directed toward the front through hole of the front shell half by the tapered surface. pressed, the front flange, the outer diameter of a feature that was formed to have a larger than the outer diameter of the seal groove.

The hermetic coupling portion corresponds to a rear flange 33 in an embodiment of the present invention described later.

According to features of the present invention, since the integrally formed front flange to a tie rod as a fastening receptacle, during assembly of the booster shell, there is no need to perform distance adjustment between the front flange and the hermetic coupling portion, the assembling property As a result, the front bolt part and nut of the tie rod can be easily attached to the front shell half of the mounting flange of the master cylinder.

Moreover, the surface facing the front portion shell halves of Installing with flanges, are defined on the tapered surface formed on the rear edge of the through hole of the mounting flange and the tie rod outer peripheral surface and in cross section triangular in tie rods An annular seal groove that surrounds the front shell half is formed, and an O-ring that is in close contact with the front shell half is attached to the seal groove, so that seal pressure is applied to the seal member at the same time that the mounting flange is attached to the front shell half. Thus, the through hole of the front shell half can be reliably sealed.

Further, the tapered surface, so that presses the O-ring in the hole of the front shell half, thereby enhancing the sealing effect on the hole of the front shell half effectively.

Furthermore , since the front flange is formed so that its outer diameter is larger than the outer diameter of the seal groove, there is no fastening axial force between the front flange and the mounting flange regardless of the presence of the seal groove. It is possible to reliably transmit, firmly hold the front shell half, and reliably apply a seal pressure to the O-ring in the seal groove.

Longitudinal sectional view of a negative pressure booster according to the implementation embodiments of the present invention. FIG. 2 is an enlarged view of part 2 of FIG. 1. FIG. 3 is a view corresponding to FIG. 2 showing a reference embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, in FIG. 1, the booster shell 1 of the negative pressure booster B is composed of a front shell half 1a and a rear shell half 1b that are each formed in a bowl shape and are connected to each other at opposite ends. The front shell half 1a and the rear shell half 1b are made of a steel plate, and they are coupled via a pair of steel tie rods 6 (only one of which is shown in FIG. 1). . The pair of tie rods 6 are arranged so as to sandwich the central axis of the booster shell 1, and by using these tie rods 6, on the front surface of the front shell half 1a, the cylinder body Ma of the master cylinder M for brakes of an automobile is arranged. And the rear shell half 1b is fastened to the front surface of the vehicle body F of the automobile by using these tie rods 6.

  The inside of the booster shell 1 is partitioned into a negative pressure chamber 2 on the front side and a working chamber 3 on the rear side by a diaphragm 5 sandwiched between the two shell halves 1a and 1b. A booster piston 4 capable of reciprocating back and forth within the booster shell 1 is disposed in an overlapping manner. The diaphragm 5 is integrally formed with a cylindrical slide seal 8 that passes through an intermediate portion of the booster piston 4 in an airtight manner and can slide on the tie rod 6. The opposing ends of both shell halves 1a and 1b are caulked together with the outer peripheral bead portion of the diaphragm 5 being clamped.

  A resin valve cylinder 10 is integrally coupled to the central portions of the booster piston 4 and the diaphragm 5. The valve cylinder 10 is slidably supported via a bearing bush 9 on a bearing cylinder 12 protruding rearward from the center of the rear shell half 1b.

  The negative pressure chamber 2 is connected to a negative pressure source V (for example, inside the intake manifold of the internal combustion engine) via a negative pressure introduction pipe 14 and a check valve 19.

  At the rear end portion of the valve cylinder 10, an air introduction port 7 for introducing air into the valve cylinder 10 is provided. Further, in the valve cylinder 10, an input rod 20 connected to the brake pedal P, and a control valve for switching the working chamber 3 to the negative pressure chamber 2 and the atmosphere introduction port 7 in accordance with the longitudinal movement of the input rod 20. 11 is disposed. That is, the control valve 11 shuts off the working chamber 3 from the atmosphere introduction port 7 and communicates with the negative pressure chamber 2 when the input rod 20 moves backward, and connects the working chamber 3 and the negative pressure chamber when the input rod 20 moves forward. 2 and a known structure that can communicate with the air inlet 7. Between the input rod 20 and the valve cylinder 10, an input return spring 13 that biases the input rod 20 in the backward direction is contracted.

  The control valve 11 includes a valve piston 18 slidably fitted to the valve cylinder 10 and connected to the front end portion of the input rod 20. A reaction force piston 17 is formed at the front end of the valve piston 18. The

  A key member 23 is attached to the valve cylinder 10 so as to abut the front end portion of the bearing cylinder 12 and define the backward limit of the valve cylinder 10 and the input rod 20.

  The valve cylinder 10 is provided with an operating piston 15 that protrudes forward and a small-diameter cylinder hole 16 that penetrates the center of the operating piston 15, and the reaction-force piston 17 is slidable in the small-diameter cylinder hole 16. To be fitted. A cup body 21 is slidably fitted on the outer periphery of the working piston 15, and the cup body 21 is filled with a flat elastic piston 22 that faces the working piston 15 and the reaction force piston 17.

  An output rod 25 is connected to the front surface of the cup body 21. Therefore, the output rod 25 is slidably supported by the valve cylinder 10 via the cup body 21. This output rod 25 is connected to the rear end portion of the master piston Mb of the master cylinder M passing through the center portion of the front shell half 1a.

  In the above, the operation piston 15, the reaction force piston 17, the elastic piston 22, and the cup body 21 constitute a reaction force mechanism 24 that feeds back a part of the output of the output rod 25 to the input rod 20.

  Between the front wall of the booster shell 1 and the front end surface of the valve cylinder 10, a booster return spring 27 that urges the valve cylinder 10 in the backward direction is contracted.

  Now, a connection structure of the front shell half 1a, the rear shell half 1b and the master cylinder M by the tie rod 6 will be described with reference to FIGS.

  The tie rod 6 includes a front bolt part 30 located at the front end, a rear bolt part 31 located at the rear end, a front flange 32 adjacent to the inner end of the front bolt part 30, and a rear bolt part 31. A rear flange 33 adjacent to the inner end is integrally formed. At this time, the distance L1 between the front and rear flanges 32 and 33 is set in advance so as to correspond to the distance L2 between the end walls between the front and rear shell halves 1a and 1b connected to each other.

  On the other hand, the front shell half 1a is provided with a front through hole 34 through which the front bolt part 30 passes, and the rear shell half 1b is provided with a rear through hole 35 through which the rear bolt part 31 passes. The rear shell half 1b is caulkingly coupled to the rear flange 33 at the peripheral edge of the rear through hole 35 in an airtight manner.

  Further, a through hole 36 through which the front bolt part 30 passes is also formed in the mounting flange Ma1 of the master cylinder M, which is overlapped with the front surface of the front shell half 1a. A tapered surface 37 is formed at the rear edge of the through hole 36, and an annular, triangular cross-sectional sealing groove 38 surrounding the tie rod 6 is defined by the tapered surface 37 and the outer peripheral surface of the tie rod 6. An O-ring 39 is attached to the seal groove 38. A nut 40 is screwed and fastened to the front bolt part 30 protruding forward of the mounting flange Ma1.

  As described above, the front flange 32 of the tie rod 6 is formed such that the outer diameter D1 thereof is larger than the outer diameter D2 of the seal groove 38.

  After the master cylinder M is attached to the front shell half 1a, the rear shell half 1b is fastened to the vehicle body F by the rear bolt portion 31 of the tie rod 6 and the nut 41 screwed and tightened thereto, and thus negative pressure is obtained. The booster B is attached to the vehicle body F.

  Next, the operation of this embodiment will be described.

  The tie rod 6 is integrally formed with a front flange 32 that supports the rear surface of the front shell half 1a and a rear flange 33 that is airtightly caulked to the rear shell half 1b. When assembling the booster shell 1 composed of the half halves 1a and 1b, it is not necessary to adjust the distance between the front and rear flanges 32 and 33, the assemblability is improved, and the front bolt portion 30 of the tie rod 6 and The attachment flange Ma1 of the master cylinder M by the nut 40 can be easily attached to the front shell half 1a.

  Moreover, the front shell half 1a and the mounting flange Ma1 of the master cylinder M are fastened by the cooperation of the front flange 32 and the nut 40 screwed to the front bolt part 30 of the tie rod 6, and at the same time, The O-ring 39 mounted in the groove 38 is pressed against and closely contacts the tapered surface 37 of the mounting flange Ma1, the front surface of the front shell half 1a and the outer peripheral surface of the tie rod 6, and the front of the front shell half 1a. The partial through hole 34 can be reliably sealed, and leakage from the front through hole 34 due to the negative pressure in the negative pressure chamber 2 can be prevented. In particular, the tapered surface 37 presses the O-ring 39 toward the front through hole 34 of the front shell half 1a, and the sealing effect on the front through hole 34 of the front shell half 1a is effective. Can be enhanced.

  Further, the front flange 32 of the tie rod 6 is formed so that the outer diameter D1 thereof is larger than the outer diameter D2 of the seal groove 38. Therefore, regardless of the presence of the seal groove 38, the front flange 32 and the master cylinder The fastening axial force can be reliably transmitted to the M mounting flange Ma1, and the front shell half 1a can be firmly clamped, and a seal pressure can be reliably applied to the O-ring 39 in the seal groove 38. it can.

Next, a reference embodiment of the present invention shown in FIG. 3 will be described.

In this reference embodiment, an annular seal groove 138 surrounding the tie rod 6 is formed on the front end surface of the front flange 32 of the tie rod 6 instead of the seal groove 38 of the mounting flange Ma1, and an O-ring is formed in the seal groove 138. 139 is mounted. The other configuration is the same as the implementation form, in FIG. 3, portions corresponding to implementation embodiments are denoted by the same reference numerals, and overlapping description is omitted.

According to this reference form, the O-ring 139 can seal the front through-hole 34 securely in close contact with the rear surface of the front shell half 1a as well as the inner surfaces of the seal grooves 138 . You can achieve the same effect as implementation form.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, it is also possible to features the seal groove 138 and O-ring 139 of reference embodiment the seal groove 3 8及 beauty O-ring 39 of the implementation forms.

B ... Negative pressure booster M ... Master cylinder Ma1 ... Master cylinder mounting flange 1 ... Booster shell 1a ... Front shell half 1b ... Rear shell half 5 ... .... Diaphragm 6 ... Tie rod 30 ... Front bolt part 32 ... Fastening receiving part (front flange)
34: Front shell half through-hole (front through-hole)
36 ... mounting flange through hole 3 8 · · · sealing groove 3 9 · · seal member (O-ring)
40 ... Nut

Claims (1)

A bowl-shaped front shell half (1a), and a bowl-shaped rear shell half (1b) opposite to the front end of the front shell half (1a) with a diaphragm (5) interposed therebetween , And tie rods (6) for connecting the front and rear shell halves (1a, 1b) to each other while passing through in the axial direction. The tie rod (6) includes a rear shell half ( airtight coupling portion that is coupled hermetically to 1b) and (33), a fastening receiving portion for supporting the rear surface of the front shell half (1a), front section half shells (1 a) and, superimposed on the front face And a front bolt half (30) penetrating through holes (34, 36) respectively provided in the mounting flange (Ma1) of the master cylinder (M), and a front shell half in cooperation with the fastening receiving portion. (1a) and the mounting flange (Ma1) are fastened In the negative pressure booster which is screwed the nut (40) to the front bolt portion (30),
The front flange (32) formed integrally with the tie rod (6) as said fastening receivers, before SL on the opposing surface of the front portion shell half of the mounting flange (Ma1) and (1a), of the mounting flange (Ma1) holes (36) tapered surface formed on the rear edge (37) and an annular seal groove (3 8 is defined in a triangular cross section with an outer peripheral surface surrounding the tie rods (6) of the tie rod (6) ) was formed, by mounting O-ring (3 9) to close the front shell half to the seal groove (3 8) (1a), wherein the said tapered surface of the O-ring (39) (37) The front flange (32) is pressed toward the front through hole (34) of the front shell half (1a), the outer diameter (D1) of which is the outer diameter (D2) of the seal groove (38). A negative pressure booster that is formed to be larger than the above .

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