JPH0525349Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tandem pneumatic booster used in brake systems of automobiles and the like.

(Prior Art) A tandem pneumatic booster generally divides the inside of a housing consisting of a front shell and a rear shell into front and rear chambers by a center plate, and slides a valve body onto the rear shell and center plate. A front power piston and a rear power piston are connected to the valve body together with a diaphragm, and the front constant pressure chamber and the rear constant pressure chamber separated by the diaphragm are communicated through a communication passage, and the front power piston and the rear power piston are connected to each other through a communication passage. The chamber and rear variable pressure chamber are connected through a communication passage provided in the valve body, and the valve mechanism built in the valve body is linked to the input shaft to generate thrust in each of the power pistons, and this thrust is transferred to the valve. The signal is configured to be transmitted to the output shaft via the body.

In such a tandem type pneumatic booster, in order to effectively transmit the thrust generated in the power piston to the output shaft, it is necessary to stably connect the front power piston or rear power piston to the valve body. However, if the structure becomes complicated with only stability in mind, the length in the axial direction will unnecessarily increase, leading to an increase in the size of the device, or it will cause troublesome assembly and increase in cost. An important issue is how to balance bond stability and structural simplification.

Conventionally, various structures have been adopted for coupling the above-mentioned valve body and power piston. For example, in Japanese Utility Model Application Publication No. 63-72274, an annular groove is provided on the outer periphery of the valve body, and this annular groove is A ring-shaped member is fitted to the valve body, and a power piston is fitted to the valve body while elastically deforming the engagement piece formed on the ring-shaped member, and the front end of the valve body is moved using the elastic recovery of the engagement piece. A pneumatic booster was shown in which the inner circumferential edge of a power piston was pressed and held against a stepped part, and Utility Model No. 63-72275
The publication describes a method of elastically deforming an engaging piece formed on a ring-shaped member, fitting the ring-shaped member into an opening of a communication passage of a valve body, and holding a power piston in the ring-shaped member. A pneumatic booster is shown. According to the structures disclosed in these publications, the power piston can be fixed to the valve body simply by using a ring-shaped member, so that the structure can be simplified.

(Problem to be solved by the invention) However, according to the above-mentioned coupling structure using a ring member, since the elastic deformation of the locking piece formed on the ring-shaped member is utilized, the structure has high rigidity. There was a problem in that it was impossible to use a ring-shaped member and looseness was likely to occur in the axial direction during use. In addition, since the power piston is directly sandwiched between the ring-shaped member and the stepped portion of the valve body, play is likely to occur in the axial direction even in the early stages of assembly, and the ring-shaped member, annular groove, or connecting There was also the problem that high-precision machining of passages and the like was required, increasing manufacturing costs.

The present invention was developed to solve the above-mentioned conventional problems, and its purpose is to provide a tandem pneumatic booster that can easily and stably connect a valve body and a power piston. shall be.

(Means for solving the problem) In order to solve the above problem, the present invention is summarized as follows: in the above-mentioned tandem type pneumatic booster, ridges are intermittently provided on the outer periphery of the valve body located in the front variable pressure chamber, on a circumference including the opening of the communicating passage, and a ring-shaped member which is fitted into the valve body and has a locking portion on its inner periphery passes between the ridges from behind and rotates to engage the locking portion with the ridges, so that the inner periphery of the front power piston and the inner periphery bead portion of the diaphragm are clamped between the ring-shaped member and a front end step portion of the valve body.

(Function) In the tandem pneumatic booster configured as described above, the ring-shaped member is rotated and engaged with the protrusion, so it is possible to use a highly rigid ring-shaped member. Moreover, since the ring-shaped member and the step at the front end of the valve body sandwich the inner peripheral edge of the front power piston and the inner peripheral bead of the diaphragm, it is possible to absorb axial play by the elastic force of the diaphragm. Become.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

In FIGS. 1 to 7, 1 is a front shell, 2 is a rear shell, and both shells form an integral housing. The inside of the housing is divided into front and rear chambers by a center plate 3, and a bottomed cylindrical valve body 4 is connected to the center plate 3 and the rear shell 2 to maintain airtightness by seal members 5 and 6. It is slidably fitted. As will be detailed later, a front power piston 7 and a rear power piston 8 are connected to the valve body 4 together with diaphragms 9 and 10, respectively, and the front chamber is divided into a front constant pressure chamber A and a front variable pressure chamber B by one diaphragm 9. The rear chamber is divided into a rear constant pressure chamber C and a rear variable pressure chamber D by the other diaphragm 10. and,
The front constant pressure chamber A and the rear constant pressure chamber C and the front variable pressure chamber B and the rear variable pressure chamber D are communicated with each other by a first communication passage 11 and a second communication passage 12 provided in the valve body 4, while the front constant pressure chamber Negative pressure from the engine is introduced into the chamber A through a negative pressure pipe 13 connected to the front shell 1.

A hole 4a is provided at the bottom of the valve body 4, and a plunger 14 is slidably fitted into the hole 4a. One end of an input shaft 15 that is linked to a brake pedal (not shown) is connected to the rear end of the plunger 14. Plunger 1
Valve seats 16 and 17 are formed at the rear end of the valve body 4 and the rear opening of the first communication passage 11, while the valve seats 16 and 17 are normally formed in the rear hollow of the valve body 4 by the biasing force of a spring 18. Poppet valve 18 seated on 17
It's decorated. The valve body 4 is also provided with a ventilation passage 19 that communicates between the rear hollow interior and the rear variable pressure chamber D, and a key member 20 that restricts the axial movement of the plunger 14 is provided in the ventilation passage 19.
is inserted. In addition, valve body 4 has
A proximal end of an output shaft 21 whose one end is connected to a master cylinder (not shown) is connected via a reaction disk 22, and the reaction disk 22 is connected to the plunger 1 through the hole 4a of the valve body 4.
It is facing 4. In addition, 23 is the valve body 4
This is a return spring for returning the

In the pneumatic booster configured as described above, when the brake pedal is depressed to move the input shaft 15 forward, the plunger 14 moves forward, its valve seat 16 separates from the poppet valve 18, and the atmosphere flows into the air passage 19. It is introduced into the rear variable pressure chamber D through the second communication passage 12, and further into the front variable pressure chamber B through the second communication passage 12. This introduction of atmospheric air creates a pressure difference between the front constant pressure chamber A and rear constant pressure chamber C, which are at negative pressure, and the rear front variable pressure chamber B and rear variable pressure chamber D, causing the front power piston 7 and the rear power piston 8 to A forward thrust is generated. This thrust is transmitted to the output shaft 21 via the valve body 4 and acts as a booster.

At this time, a reaction force is transmitted to the brake pedal via the rear action disk 22, plunger 14, and input shaft 15. When the input from the brake pedal disappears, the plunger 14 retreats and its valve seat 16 comes into contact with the poppet valve 18.
Further, the valve seat 17 of the first communication path 11 is opened. As a result, the introduction of atmospheric air into the rear variable pressure chamber D is cut off, and the negative pressure in the front constant pressure chamber A and the rear constant pressure chamber C is transferred to the rear variable pressure chamber D and the front variable pressure chamber through the first communication path 11 and the ventilation path 19. B, the pressure difference decreases and the thrust force decreases. The pressing force of the return spring 23 returns the entire structure to its original state.

As shown in detail in FIG. 2, the front power piston 7 and the diaphragm 9 are fixed to the valve body 4 at one end by a protrusion 31 fitted into the valve body 4 and provided on the outer periphery of the valve body 4. The ring-shaped member 35 engages the inner peripheral edge 7a of the front power piston 7 and the inner peripheral bead 9a of the diaphragm 9 together with the valve body 4.
This is done by pressing and holding against the back part (step part) 30a of the outer flange 30 provided at the front end of the outer flange 30.

As shown in FIGS. 3 and 4, the protrusion 31 includes a plurality of openings 12a, 12 of the communication passage 12 that connects the front variable pressure chamber B and the rear variable pressure chamber D.
Two strips are provided on the circumference connecting points a and facing the areas that avoid the openings 12a, 12a. Each protrusion 31 also has a claw portion 32 at one end in the same circumferential direction that protrudes toward the stepped portion 30a of the outer flange 30.
The other end opposite to the claw portion 32 is connected to the stepped portion 30a via a connecting portion 33. Step portion 3 of this outer flange 30
0a consists of two stepped surfaces, and a groove 34 is formed between one of the stepped surfaces and each protrusion 31 (FIGS. 2 and 3). Note that the claw portion 3 of each protrusion 31
2 and the connecting portion 33, and the gap a defined by the claw portion 32 of each protrusion 31 and one of the stepped surfaces (Fig. 3) are the length l of the groove 34 defined by the connecting portion 33 (Fig. 3), respectively. It has a close relationship with the shaped member 35.

On the other hand, the ring-shaped member 35 is
As shown in the figure, a cylindrical main body 36 and a curled part 3 extending radially outward from one end of the main body 36
7, and two locking portions 38 extending radially inward from the other end of the main body portion 36 and bent in the axial direction. The locking portion 38 is configured to close the gap a between the claw portion 32 of the protrusion 31 and the stepped surface of the valve body 4.
The axial length a′ (second
), and has a circumferential length l' slightly shorter than the length l of the groove 34. The engaging portion 38
Further, the diameter D of the inner circumferential circle is approximately equal to the outer diameter of the valve body 4. That is, the ring-shaped member 35 has its engaging portion 38 connected to the protrusions 31 and 3.
By positioning it between 1 and 1, it is allowed to move forward, and when it is rotated at its forward end, the engaging portion 38 engages the claw portion 32 of the protrusion 31 and the stepped surface of the valve body 4. The groove 34 passes through the gap a between
It is now possible to go inside. Note that the curl portion 37 is provided with a notch 39 for mounting a rotation jig (not shown) to be described later.

With this configuration, in order to assemble the front power piston 7 and diaphragm 9 to the valve body 4, first, fit the front power piston 7 and diaphragm 9 onto the valve body 4 so as to overlap them, and then press the inner peripheral edge of the front power piston 7. The portion 7a and the inner peripheral bead 9a of the diaphragm 9 are brought into contact with the stepped portion 30a of the outer flange 30 of the valve body 4.
Next, the ring-shaped member 35 is fitted into the valve body 4,
The engaging portion 38 is positioned between each of the protrusions 31 and passed through the protrusion 31 from behind, and then a rotating jig is attached to the notch 39 of the curled portion 37 of the ring-shaped member 35, and the ring-shaped member Turn 35. Then, the ring-shaped member 35 enters into the groove 34 between each protrusion 31 and the stepped surface of the valve body 4, and due to the elasticity of the bead 9a of the diaphragm 9, the rear end of the engaging portion 38 is pushed. It is made to engage with the protrusion 31. As a result, the inner circumferential edge 7a of the front power piston 7 and the inner circumferential bead 9a of the diaphragm 9 are firmly sandwiched between the stepped portion 30a of the outer flange 30 of the valve body 4 and the ring-shaped member 35. It becomes like this.

(Effects of the invention) As explained above in detail, according to the tandem pneumatic booster according to the invention, the ring-shaped member fixing the front power piston 7 to the valve body 4 can be rotated. Since it was made to engage with the protrusion by utilizing the ring-shaped member, a highly rigid ring-shaped member could be used, and the stability of the joint structure could be ensured. In addition, since the ring-shaped member holds down the inner peripheral edge of the front power piston and the inner peripheral bead of the diaphragm, it is possible to absorb axial play by the elastic force of the diaphragm, making it easier to assemble. This eliminates the need for high precision, resulting in a reduction in manufacturing costs.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a tandem pneumatic booster according to the present invention, Fig. 2 is an enlarged sectional view of its main parts, Fig. 3 is an enlarged plan view of its main parts, and Fig. 4 is an enlarged plan view of its main parts.
Fig. 5 is a plan view of the ring-shaped member, Fig. 6 is a sectional view taken along the - arrow line in Fig. 5, and Fig. 7 is a cross-sectional view of the present tandem pneumatic booster. It is a front view. 1...Front shell, 2...Rear shell, 3
... Center plate, 4 ... Valve body,
7, 8... Power piston, 9, 10... Diaphragm, 12... Communication passage, 12a... Opening, 1
4... Plunger, 15... Input shaft, 18... Poppet valve, 21... Output shaft, 30a... Step portion,
31... Projection, 35... Ring-shaped member, 38...
Engagement part, A, C... Constant pressure chamber, B, D... Variable pressure chamber.

Claims (1)

[Scope of utility model registration request] The inside of the housing, which consists of a front shell and a rear shell, is divided into front and rear chambers by a center plate, and a valve body is slidably fitted into the rear shell and center plate, and the valve body has a front power piston and a rear chamber. The power pistons are connected to each other with a diaphragm, and the front constant pressure chamber and the rear constant pressure chamber separated by the diaphragm are communicated through a communication passage, and the front pressure change chamber and the rear pressure change chamber are connected to each other through a communication passage provided in the valve body. A tandem type pneumatic doubler that generates thrust in each of the power pistons by interlocking the valve mechanism built in the valve body with the input shaft, and transmits this thrust to the output shaft via the valve body. In the power device, protrusions are intermittently provided on the outer periphery of the valve body located in the front pressure transformation chamber, including the opening of the communication passage, and are fitted onto the valve body and locked to the inner periphery. passing between the respective protrusions from behind the protrusions and rotating a ring-shaped member having a
The locking portion is engaged with the protrusion, and the inner circumferential edge of the front power piston and the inner circumferential bead of the diaphragm are held between the ring-shaped member and the front end stepped portion of the valve body. Tandem type pneumatic booster.