KR100305601B1 - Co upling structure and method of push rod and hydraulic piston in a clutch booster - Google Patents

Abstract

Simplify the configuration of the connection between the push rod 16 and the hydraulic piston 22, reduce costs, generate sound when operating the clutch pedal, and generate shock from the clutch pedal. To prevent. The power piston 10 is operated by the air introduced into the pressure chamber 12 of the power cylinder 2, and this output is transmitted to the hydraulic cylinder 4 through the push rod 16 connected to the power piston 10. To the piston 22. The insertion hole 22a is formed in the end surface of the hydraulic piston 22, and the annular groove 22b is formed in the inner surface of this hole 22a. On the other hand, the annular groove (16b) is also formed on the outer peripheral surface of the front end of the push rod (16). The wire rod 41 and the hydraulic piston 22 are connected to each other by simultaneously fitting the wiring 41 into these ring grooves 16b and 22b.

Description

Structure and connection method of push rod and hydraulic piston of clutch powering device {CO UPLING STRUCTURE AND METHOD OF PUSH ROD AND HYDRAULIC PISTON IN A CLUTCH BOOSTER}

The present invention relates to a clutch boosting device, and in particular, to a push rod connected to a front face of a power piston, a connection structure between a hydraulic piston to which an output of a power piston is transmitted by sandwiching the push rod, and a connection method thereof. .

The clutch power booster is generally operated by a control valve which is switched by operation of a clutch pedal and supplies compressed air to a pressure chamber of a power cylinder, and a power piston operated by compressed air introduced into the pressure chamber. And a piston of a hydraulic cylinder in which the push rod connected to the power piston is integrally moved forward and backward, the hydraulic cylinder to which the output of the power piston is transmitted by sandwiching the push rod, and the hydraulic piston is pushed in and out. And a push rod for clutch operation which performs a single contact of the clutch while rotating the clutch outer lever.

The relationship between the conventional push rod 116 and the hydraulic piston 122 will be described with reference to FIG. 6. The push rod 116 is fixed to the front side of the power piston 110 which partitions the inside of the power cylinder 102 into the pressure chamber 112, the waiting chamber 114, etc., and retreats integrally. The front end of the push rod 116 extends toward the hydraulic cylinder 104 through the inside of the push rod guide 128 accommodated into the housing 118, and the front end thereof is a cross section of the hydraulic piston 1 22. It is in contact with the recess of. Further, the rear end face of the clutch operation push rod 147 connected to the clutch outer lever (not shown) is in contact with the front side of the hydraulic cylinder 104.

When the clutch pedal (not shown) is pressed down and pushed in, the clutch power supply device sends the hydraulic pressure from the master cylinder to the hydraulic chamber 124 of the hydraulic cylinder 104 through the passage 162 in the housing 118, Furthermore, the control valve 106 is changed by sending it to the hydraulic chamber of the control valve 106 (not shown) through the inner passage 160, and the compressed air is introduced into the pressure chamber 112 of the power cylinder 102. It is intended to operate 110. In this operation, first, the hydraulic piston 122 is stroked by the hydraulic pressure introduced into the hydraulic chamber 124 of the hydraulic cylinder 104, and the clutch side (right side of the drawing) is more than this piston 122. Narrow your margins. Then, the power piston 10 is stroked by the compressed air introduced through the control valve 106, and the push rod 116 is brought into contact with the hydraulic piston 122, and further, the stroke is Clutch operation is carried out.

As described above, first, after the hydraulic piston 122 is stroked, the power piston 110 and the push rod 116 start the stroke, so that the push rod 116 is previously stroked. There was a problem that the hitting occurs when contacted by contact with the hydraulic piston 122. In addition, since the hydraulic piston 122 does not move until the power piston 110 starts the stroke and the push rod 116 contacts the hydraulic piston 122, the portion of the push rod 116 is stroked. The volume in the hydraulic chamber 124 of the hydraulic cylinder 104 is reduced, and the hydraulic pressure in the hydraulic cylinder 104 rises. This hydraulic rise was transmitted to the master cylinder, causing a momentary shock to the clutch pedal.

7 shows another example of a clutch power booster having a conventional connection structure between a push rod and a hydraulic piston, and this clutch power booster has a built-in clutch wear adjustment function. When the clutch booster is actually installed in the clutch, the power piston 210 is located approximately in the middle of the power cylinder 202 and gradually retreats (moves to the left in the drawing) as the clutch wears. Then, when the retracted power piston 210 presses the wear alarm switch 284, an alarm is generated.

In the example of FIG. 7, the spring 215 is arranged in the pressure chamber 212, and the power piston 210 is pushed toward the hydraulic piston 222 side. On the contrary, the spring is arranged toward the waiting chamber 214 side. Also, clutch power boosters having a configuration in which a power piston 210 is applied in a direction away from the hydraulic piston 222 are also widely known. In the case of such a structure, it is necessary to connect the hydraulic piston 222 and the push rod 216 on the power piston 210 side, etc. Usually, these pins 286 are similar to the structure of FIG. Both are connected (216, 222).

In the conventional configuration described above, the connection between the push rod 216 and the hydraulic piston 222 is cumbersome. In particular, as shown in FIG. 7, when the housing 218 on the power cylinder 202 side and the body 220 or the like of the hydraulic cylinder 204 are integrally formed, the push rod 216 is connected to the push rod 216. , The oil seal 270 or the cup seal 274 of the push rod guide 228 is fitted, and the hydraulic piston 222 is connected with the pin 286 to the wiring 288. After the pin 286 is prevented from escaping, the pin 286 is incorporated into the housing 218 to be joined by a snap ring 280. Therefore, there was a problem that the bonding property was bad.

The present invention has been made to solve the above problems, and the connection structure and connection method of the push rod and the hydraulic piston of the clutch power supply device that does not generate a hitting sound when the stepping on the clutch pedal, or impart shock to the pedal The purpose is to provide. It is also an object of the present invention to provide a connection structure and a connection method between a push rod and a hydraulic piston of a low-cost clutch boosting device having a simple structure and good assembly.

1 is a longitudinal cross-sectional view of a clutch power booster having a connection structure between a push rod and a hydraulic piston according to an embodiment of the present invention.

2 is an enlarged longitudinal sectional view of the connection structure between the power piston and the push rod of the clutch power booster.

3 is an enlarged longitudinal sectional view showing an example of the connection structure between the push rod and the hydraulic piston.

4 is a diagram illustrating an example of wiring used for connecting the push rod and the hydraulic piston.

It is a figure explaining the engagement state of said wiring.

Fig. 6 is a cross-sectional view of the main portion (connecting portion of the push rod and the hydraulic piston) of the conventional clutch booster.

7 is a view showing another example of the conventional clutch booster.

(Explanation of symbols on the main parts of drawing

2 … Power cylinder

4 … Hydraulic cylinder

10... Power piston

12... Pressure chamber

16. Push rod

16b. Ring Groove of Push Rod

22. Hydraulic piston

22a... Hole of hydraulic piston

22b. Ring Groove of Hydraulic Piston

22c... Chamfer

41…. Wiring

The connection structure between the push rod and the hydraulic piston of the clutch booster according to the present invention operates the power piston by air introduced into the pressure chamber of the power cylinder, and outputs the output of the hydraulic cylinder through the push rod connected to the power piston. It is provided in the clutch powering device which transmits to the piston. In particular, a hole is formed in the end face of the hydraulic piston, and an annular groove is formed in the inner circumferential surface of the hole, and an annular groove is formed in the outer circumferential surface of the end of the push rod. In addition, the push rod and the hydraulic piston and the like are connected by sandwiching wiring wires which are simultaneously hooked into both ring-shaped grooves.

In addition, the method of connecting the push rod and the hydraulic piston of the clutch power booster according to the present invention inserts a substantially arc-shaped wiring cut into a ring groove provided in the inner surface of the hole formed on the end surface of the hydraulic piston. Next, the push rod having the annular groove on the outer circumferential surface is inserted into the wiring so as to pass through it, and then the wiring is inserted into the annular groove of the push rod, thereby the both ring grooves. It is combined with

EMBODIMENT OF THE INVENTION Below, this invention is demonstrated by embodiment shown in drawing. Fig. 1 is a longitudinal sectional view of a clutch power booster having a connection structure between a push rod and a hydraulic piston according to Embodiment 1 of the present invention. The clutch power booster includes a power cylinder 2, a hydraulic cylinder 4 and The control valve 6 etc. are provided.

The power cylinder 2 has a power piston 10 which is fitted to slide freely into the cylinder shell 8, and the power piston 10 pushes the inside of the cylinder shell 8 into the pressure chamber 12. ), The waiting room 14 and the like. A push rod 16 is connected to the shaft portion of the power piston 10 to integrally move forward and backward. The power piston 10 is applied to the pressure chamber 12 by a return spring 15 arranged in the waiting chamber 14, and stops at the position shown in FIG. have.

The connection structure between the power piston 10 and the push rod 16 will be described. At the central portion of the front surface of the power piston 10 (the direction in which the power piston 10 moves during operation, that is, the right side of FIG. 1 is referred to as the front), a push rod connecting portion 10a protruding in a cylindrical shape is formed, Into the bottomed hole 10b of the cylindrical connecting portion 10a, the rear end of the push rod 16 is connected by sandwiching the push rod holding member 11 therebetween.

2, the push rod holding member 11 holds a cup-shaped portion 11a, a flange 11b formed on the opening side thereof (right side of the drawing), and the like. An annular groove 11c is provided on the inner circumferential surface of 11a). And the chamfer 11d is formed in the wall surface of the entrance part side of this annular groove 11c. On the other hand, an annular groove 16a is also formed on the outer peripheral surface of the end of the push rod 16. The wiring 13 is simultaneously fitted into both of the push-rod supporting members 11 and the ring-shaped grooves 11c and 16a of the push rod 16 so that the push rod 16 and the push rod supporting member 11 and the like are fitted. Is connecting.

A female screw is formed on the inner circumferential surface of the bottomed hole 10b of the power piston 10, and a male screw is formed on the outer circumferential surface of the push rod supporting member 11, and this push rod supporting member 11 is formed. By twisting into the bottomed hole 10b, the push rod support member 11 and the push rod 16 connected to the support member 11 are fixed to the power piston 10. Thus, in the state in which the push rod support member 11 is screwed into the hole 10b of the power piston 10, the flange 11b of the push rod support member 11 has the cylindrical shape of the power piston 10. It is in contact with the front end surface of the phase connection part 10a.

In addition, in this embodiment, the structure of the connection part of the push rod 16 and the push rod support member 11 is the front end part (right side of FIG. 1) and the hydraulic piston 22 of the push rod 16 demonstrated later. Although the structure is the same as that of the structure of the connection part, it is not limited to such a structure and may be fixed by caulking etc. similarly to the conventional clutch booster.

Further, a small cup seal 21, a wear ring 23, and the like are fitted to the sliding portion of the power piston 10 with the cylinder shell 8 around the outer circumference. By using such a small cup seal 21, the resistance to slipping can be reduced without deteriorating the durability and airtightness of the seal member, and the operation sealing of the clutch pedal can be made excellent.

The hydraulic cylinder 4 is provided in the cylinder body 20 fixed to the housing 18 which closes and closes the inlet part of the cylinder shell 8. The O-ring 19 is fitted between the housing 18 and the cylinder body 20 so as to be fitted. The hydraulic piston 22 is arranged to slide in the cylinder hole 20a of the cylinder body 20. The hydraulic piston 22 divides the inside of the cylinder hole 20a into a hydraulic chamber 24 on the power cylinder 2 side, a waiting chamber 26 on the front end side, and the like. 51, 53 hold | maintain the liquid tightness and airtight between the chambers 24 and 26. As shown to FIG.

The push rod 16 connected to the power piston 10 extends toward the hydraulic cylinder 4 through the inside of the guide portion (denoted by reference numeral 28 as a whole) held at the center of the housing 18. have. The housing 18 is provided with a concave portion 18c that protrudes toward the waiting chamber 14 side of the power cylinder 2 and has a through hole 18b formed on the bottom thereof, and is described above into the concave portion 18c. The guide part 28 is accommodated. The guide portion 28 includes an annular seal support member 29 and a liquid leakage preventing seal member 31 incorporated into an annular recess formed on both ends of the inner surface of the seal support member 29. An air suction prevention seal member 33 is provided. Both sealing members 31 and 33 are constituted by Y packing. The seal supporting member 29 is made of resin. The annular seal supporting member 29 has an inner diameter substantially coinciding with the outer diameter of the push rod 16 and an outer diameter substantially coinciding with the inner diameter of the recess 18c of the housing 18. The push rod 16 penetrates into the recess 18c of the housing 18 and penetrates the inner circumferential portion thereof. An O-ring 37 is fitted to the outer circumference of the seal support member 29 to maintain liquid tightness and airtightness on the outer circumferential side of the guide portion 28.

The guide portion 28 joins a ring plate 39 to the inlet side of the recessed portion 18c of the housing 18 and is formed by the end of the cylinder body 20 fixed to the housing 18. It is fixed by being pressed. The air suction prevention seal member 33 incorporated in the seal support member 29 is prevented from escaping by the inner peripheral part of the bottom surface of the recessed portion 18c of the housing 18, while preventing the liquid leakage. The seal member 31 is prevented from escaping by the ring plate 39 described above.

The front end of the push rod 16 penetrating the inside of the guide portion 28 is connected to a hydraulic piston 22 which is fitted to slide into the cylinder body 20. In the end face of the hydraulic piston 22 on the power cylinder 2 side, an insertion hole 22a having an inner diameter slightly larger than the outer diameter of the push rod 16 is formed (see FIG. 3 to enlarge and display the connecting portion). The front end of the push rod 16 is inserted into this insertion hole 22a. An annular groove 22b is formed on the inner circumferential surface of the insertion hole 22a of the hydraulic piston 22, and an annular groove 16b is formed on the outer circumferential surface of the front end of the push rod 16, respectively. The chamfer 22c is formed in the wall surface of the opening side (left side of FIG. 3) of the annular groove | channel 22b of the inner periphery of the hydraulic piston 22. As shown in FIG.

A wiring 41 is fitted into both of the ring grooves 22b and 16b, and both of them are connected together by being pushed together with the push rod 16 and the hydraulic piston 22 and the like. The angle of inclination of the chamfer 22c is set at an angle at which the push rod 16 is pulled out when a load of a predetermined or more acts.

The wiring 41 has a shape having a length of about three quarters in a free state in which a part of a substantially circular ring is cut. As shown in FIG. 4, the wiring 41 is slightly deformed and has a diameter D in a direction orthogonal to the diameter D ₁ (up and down direction in FIG. 4) of the portion holding the cut portion 41a. ₂ ) is slightly enlarged on both sides. Therefore, when fitting this wiring 41 with both ring-shaped grooves 16b and 22b, it does not engage with the ring-shaped groove 22b of the hydraulic piston 22 in the whole circumference, and it is two places 41b and 41c on both sides. ), So as to fit together (see Fig. 5). As described above, the chamfer 22c of a predetermined angle is formed in the annular groove 22b of the hydraulic piston 22, and the wiring 41 is formed in the annular groove 22b of the hydraulic piston 22. On the contrary, since only a part (41b, 41c) is applied, not the entire circumference, the push rod (16) does not escape from the hydraulic piston (22) at a pulled load of less than or equal to a predetermined load. In this case, the push rod 16 can be pulled out from the insertion hole 22a of the hydraulic piston 22.

In the configuration of the present embodiment, when the push rod 16 is stuck to the hydraulic piston 22, the wiring 41 is first inserted into the annular groove 22b of the hydraulic piston 22. Then, the push rod 16 is inserted into the insertion hole 22a of the hydraulic piston 22. The tip 16c of the push rod 16 is tapered as shown in FIG. 3, and the wiring 41 is inserted into the hole while widening the range, and the annular groove 1 of the push rod 16 is thereafter. When 6b) reaches the position of the wiring 41, the wiring 41 is inserted into the annular groove 16b. As described above, the push rod 16 and the hydraulic piston 22 can be connected to each other by a simple operation, and thus the cost can be reduced.

Further, the push rod 47 for clutch operation is in contact with the front surface (cross section of the waiting chamber 26 side) of the hydraulic piston 22. Moreover, the other end of this clutch operation push rod 47 is connected to a clutch out lever not shown.

The control valve 6 is provided in the valve hole 18a, 30a formed from the housing 18 and the valve housing 30 fixed to this housing 18. As shown in FIG. In the valve hole 30a, a valve lifter 32 is fitted so as to be free to slide. On the housing 18 side of the valve lifter 32, a diaphragm 43 is sandwiched between the stair part on the inner surface of the valve hole 18a and the annular retainer 45. As shown in FIG. The valve lifter 32 includes a middle diameter portion 32a supported so as to be free to slide into the valve hole 30a of the valve housing 30, and a small diameter portion that penetrates the annular retainer 45. (32c), a large diameter portion 32b in the middle thereof, and the like, and a sealing member 49 is fitted to the outer circumference of the middle diameter portion 32a.

By the diaphragm 43 and the sealing member 49 of the outer periphery of the valve lifter 32, the valve hole 18a, 30a is divided into the hydraulic chamber 34, the exhaust chamber 35, and the transformer chamber 36. It is.

The valve lifter 32 is always exerted a force toward the hydraulic chamber 34 by a spring 38 disposed in the transformer chamber 36. When the valve lifter 32 is not operated, the large diameter portion 32b has an annular retainer 45. ) Is stopped, and when hydraulic pressure from the master cylinder is introduced into the hydraulic chamber 34, the diaphragm 43 is pressed to move to the right in FIG. In the valve lifter 32, an axial direction and a radial passage 32d are formed, and one end of the inner passage 32d opens to the front end of the transformer chamber 36 side, The other end is opened into the exhaust chamber 35, and is opened to the atmosphere by sandwiching an exhaust cover (not shown).

The poppet valve 42 is arranged freely to slide near the opening (right side of the drawing) of the valve hole 30a of the valve housing 30 described above. The poppet valve 42 faces the valve lifter 32 described above with the small diameter portion 30b whose head portion 42a is formed into the valve hole 30a. The cap 44 is inserted into the opening side of the valve hole 30a and is fixed by the retaining ring 46 so as not to fall out of the valve hole 30a. The small diameter shaft portion 42b of the poppet valve 42 fits freely on the inner circumferential surface of the cap 44 so that the poppet valve 42 is guided in and out. O-rings 48 and 50 are fitted to the outer circumferential surface of the shaft 44b of the poppet valve 42 which slides the inner circumferential surface of the cap 44 and the outer circumferential surface of the cap 44 fitted with the inner circumferential surface of the valve hole 30a. In addition, the airtightness is maintained between the pneumatic chamber 52 on the inner side of the valve hole 30a and the outside of the valve hole 30a.

A spring 54 is fitted between the rear side (right side of the drawing) of the head portion 42a of the poppet valve 42 and the front end surface of the cap 44, and the poppet valve 42 is connected to the valve. A force is applied to the lifter 32 side. When the control valve 6 is inoperative, the head portion 42a of the poppet valve 42 applied to the spring 54 is formed on the side surface of the small diameter portion 30b of the valve hole 30a. The valve seat 56 is seated. In a state where the poppet valve 42 is seated on the valve seat 55, the pneumatic chamber 52 connected with an air tank (not shown) with a compressed air supply port 58 interposed therebetween, The said transformer chamber 36 is interrupted | blocked. The poppet valve 42 is made of metal in the conventional configuration, but is made of resin in the present embodiment. In this way, the poppet valve 42 is resinized, thereby making it possible to reduce the weight and the cost.

The compressed air supply port 58 of the control valve 6 described above is connected to an air tank (not shown), and the transformer chamber 36 is a supply port 30c of the valve housing 30 and a pipe 66. ) And the like are connected to the pressure chamber 12 of the power cylinder 2.

The hydraulic chamber 34 of the control valve 6 is connected to and connected to the hydraulic chamber 24 of the hydraulic cylinder 4 by a passage 60 formed in the housing 18. The hydraulic chamber 24 is connected to the inlet port 64 by a passage 62 formed in the housing 18. Moreover, the inlet port 64 of the housing 18 is connected to the output pressure chamber of the master cylinder (not shown) operated by the clutch pedal.

In addition, although the end (rear end) of the cylinder body 20 is directed into the hydraulic passages 60 and 62 formed in the housing 18 described above, the hydraulic pressure conveyed from the master cylinder is supplied to the hydraulic cylinder 4 at this end. Passage grooves 20b and 20c are formed to supply the hydraulic chamber 24 of the control panel 24 and the hydraulic chamber 34 of the control valve 6. Although the shape and size of these passage grooves 20b and 20c can be appropriately set, in particular, the passage groove 20b on the master cylinder side should ensure a passage area of sufficient size in terms of responsiveness. Preferably, the passage groove 20c on the control valve 6 side preferably has a small cross-sectional area so as to retain an orifice effect, and may be a small slit or a small hole.

The operation of the clutch booster according to the above configuration will be described. Stepping on the clutch pedal (not shown), the liquid in the output pressure chamber of the master cylinder passes through the passage 62 and the passage groove 20b of the cylinder body 20 at the inlet port 64 of the housing 18. It is conveyed to the hydraulic chamber 24 of the hydraulic cylinder 4, and it is conveyed to the hydraulic chamber 34 of the control valve 6 by sandwiching the channel | channel groove | channel 20c and the channel | path 60 between them. Therefore, although the hydraulic piston 22 is pushed toward the right side of FIG. 1, since the hydraulic piston 22 is connected to the push rod 16, only the hydraulic piston 22 does not stroke. In addition, by the hydraulic pressure introduced into the hydraulic chamber 34 of the control valve 6, the valve lifter 32 is moved to the right in the drawing with the diaphragm 43 interposed therebetween.

When the valve lifter 32 moves, first, the front end of the valve lifter 32 comes into contact with the head portion 42a of the poppet valve 42 so that the passage 32d inside the valve lifter 32 is closed. In addition, the valve lifter 32 moves to move the poppet valve 42 to the seat of the valve 56. When the poppet valve 42 is moved from the valve seat 56, the pneumatic chamber 52, the transformer chamber 36, etc., which are connected to the compressed air supply port 58, are connected. Then, the compressed air of the air tank passes through the transformer chamber 36 in the pneumatic chamber 52 and is supplied to the pressure chamber 12 of the power cylinder 2. The compressed air supplied to this pressure chamber 12 moves the power piston 10 to the right side of FIG. When the power piston 10 is advanced, the push rod 16 and the hydraulic piston 22 connected thereto are integrally moved to the right side of FIG. 1, and the clutch operated push rod 4 7 is advanced. As the clutch-operated push rod 47 moves forward, the clutch outer lever operates to break the clutch.

Since the push rod 16 and the hydraulic piston 22 and the like are connected and integrated as described above, when the power piston 10 and the push rod 16 are stroked as in the conventional configuration shown in FIG. The tip of the push rod 16 does not collide with the hydraulic piston 22, so that no batting occurs. In addition, since the hydraulic piston 22 does not strike in advance, the volume of the hydraulic chamber 24 of the hydraulic cylinder 4 does not change during the stroke of the push rod 16, and shock is applied to the clutch pedal. It is not delivered.

When the stepping force of the clutch pedal is released, the pressure in the hydraulic chamber 34 of the control valve 6 is lowered, and the valve lifter 32 is returned to the state of FIG. 1 by the spring 38. Then, the inner passage 32d of the valve lifter 32 is opened, and the transformer chamber 36 is connected to the exhaust chamber 35 via the inner passage 32d to communicate with the pressure chamber of the power cylinder 2. The air in (12) is discharged to the atmosphere by sandwiching the pipe 66, the transformer chamber 36, the inner passage 32d, the exhaust chamber 35, and an exhaust cover (not shown). Then, the power piston 10, the push rod 16, the hydraulic piston 22 and the clutch operating push rod 47 return to the state of FIG. 1, the clutch out lever returns, and the clutch is connected again.

As mentioned above, according to the connection structure of this invention, a hole is formed in the cross section of a hydraulic piston, an annular groove is provided in the inner peripheral surface of this hole, and an annular groove is provided in the outer peripheral surface of the end part of a push rod. And the push rod and the hydraulic piston, etc. are connected by sandwiching wiring wires which are simultaneously hooked into both ring-shaped grooves, so that the structure can be simplified and the cost can be reduced. Can be. In addition, since only the hydraulic piston is not stroked ahead of time during the clutch pedal operation, it is possible to prevent the occurrence of hitting and shock on the clutch pedal. In addition, according to the connection method according to the present invention, it is possible to connect the push rod and the hydraulic piston by an extremely simple operation.

Claims (5)

In the clutch powering device which operates the power piston by the air introduced into the pressure chamber of the power cylinder and transmits this output to the piston of the hydraulic cylinder by sandwiching the push rod connected to the power piston, a hole is formed in the end surface of the hydraulic piston. And the annular groove is formed on the inner circumferential surface of the hole, and the annular groove is formed on the outer circumferential surface of the push rod, and the push rod described above is sandwiched between the two wires which are simultaneously engaged into the annular grooves. And a connecting structure between the push rod and the hydraulic piston of the clutch booster, characterized in that the hydraulic piston and the connection. 2. The connecting structure between the push rod and the hydraulic piston of the clutch power booster according to claim 1, wherein the annular groove of the hydraulic piston has a chamfer formed on the wall surface of the opening side of the hole. 3. The connection structure between the push rod and the hydraulic piston of the clutch power booster according to claim 1 or 2, wherein the wiring has a substantially circular arc shape with a part cut off. 4. The push rod and the hydraulic piston of claim 3, wherein the wiring has a deformed arc shape, and a portion protruding outward from the circle is combined with the annular groove of the hydraulic piston. Structure of connection with. Connect the hydraulic piston and the push rod of the clutch booster which transfers the power piston to the piston of the hydraulic cylinder by interposing the push rod connected to the power piston through the air introduced into the pressure chamber of the power cylinder. In the method of the present invention, a generally circular arc-shaped wiring is partially inserted into an annular groove provided on the inner surface of the hole formed in the end surface of the hydraulic piston, and then a push rod holding the annular groove on the outer circumferential surface is wired. The method of connecting the push rod and the hydraulic piston of the clutch power booster, characterized in that it is inserted into the ring to pass through to widen the range, and thereafter, the wire is inserted into the annular groove of the push rod and combined with both ring grooves.