JP2000035058A - Push rod guide for clutch booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure by reducing the number of components for a push rod guide. SOLUTION: A body 20 of a hydraulic cylinder 4 is fixed to a housing for closing an opening of a power cylinder 2. A power piston 10 and a hydraulic piston 22 are connected with each other via the push rod 16 penetrating a push rod guide 28. The push rod guide 28 is provided with a resin annular holding member 29, an air suction preventing seal member 33 fitted to the both ends of the internal circumference, and a liquid leakage prevention seal member 31 and stored in a recessed part 18c formed in the housing 18. One of the both seal members 31, 33 is prevented from being pulled out by the internal circumference of the housing and the other by the fixing plate 39, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch booster, and more particularly, to a push-rod for transmitting an output of a power piston to a hydraulic piston, for guiding forward and backward movement of the push rod. The present invention relates to a push rod guide that maintains liquid tightness and air tightness.

[0002]

2. Description of the Related Art A clutch booster generally includes a control valve which is switched by operating a clutch pedal to supply compressed air to a pressure chamber of a power cylinder, and a power piston which is operated by compressed air introduced into the pressure chamber. A push rod connected to the power piston to move forward and backward integrally, a piston of a hydraulic cylinder to which the output of the power piston is transmitted via the push rod, and a forward and backward movement through the hydraulic piston, And a push rod for operating the clutch for rotating and disengaging the clutch outer lever.

[0003] A push rod for transmitting the operation of the power piston to the hydraulic piston passes through a guide portion provided at the center of a housing that partitions between the power cylinder and the hydraulic cylinder. In addition to guiding the push rod forward and backward, the liquid leakage from the hydraulic cylinder side and the suction of air from the power cylinder side are prevented.

A conventional structure of the above-described push rod guide will be described with reference to FIG. A cylinder body 120 of the hydraulic cylinder 104 is connected to a housing 118 that closes an opening of the power cylinder 102. A central portion of the housing 118 protrudes toward the atmosphere chamber side of the power cylinder, and a concave portion 118c is formed on the hydraulic cylinder side.
A push rod guide (indicated by reference numeral 128 as a whole) is mounted therein. Power piston 1 that partitions the inside of power cylinder 102 into pressure chamber 112 and atmosphere chamber 114
A push rod 116 connected to the piston 10 penetrates the guide portion 128, and the tip of the push rod 116 contacts the end face of the hydraulic piston 122.

In the push rod guide 128 mounted on the housing 118, the oil seal 170 is first pressed into the recess 118c, and then the bearing 172, the cup seal 174, the cup seal retainer 176, and the plate 178 are sequentially inserted. Finally, the snap ring 180 is configured by being incorporated into the groove of the housing 118.

FIG. 7 shows another configuration of a conventional push rod guide 228. The push rod guide 228 is formed from a hydraulic cylinder 204 side in a hole 218c of a housing 218.
Oil seal holding member 27 into which cup seal retainer 270, cup seal 272, and oil seal 274 are press-fitted.
6 and the plate 278 are sequentially inserted into the housing 2
A snap ring 280 is incorporated in the groove of the opening on the side of the power cylinder 202 of No. 18. The oil seals 170 and 274 prevent suction of air from the air chambers of the power cylinders 102 and 202 to the hydraulic cylinders 104 and 204, and the cup seals 174 and 27.
Reference numeral 2 is for preventing liquid leakage from the hydraulic cylinders 104 and 204 to the atmosphere chamber.

[0007]

As described above, the conventional push rod guide of the clutch booster has a problem that the number of parts is large, the structure is complicated, and the assembling property is poor. In particular, there is a disadvantage in that it takes time to press-fit the oil seal and install the snap ring. Further, the oil seal has a problem that the cost is high and the followability in the radial direction is weak.

An object of the present invention is to provide a push rod guide of a clutch booster which can reduce the number of parts and simplify the structure. is there. Further, it is another object of the present invention to provide a push rod guide of a clutch booster which is excellent in assemblability without requiring operations such as press-fitting of an oil seal and installation of a snap ring.

[0009]

A push rod guide of a clutch booster according to the present invention operates a power piston by compressed air introduced into a pressure chamber of a power cylinder, and outputs the output of the push piston connected to the power piston. A clutch booster that transmits to a piston of a hydraulic cylinder via a rod is mounted on a housing that separates the power cylinder and the hydraulic cylinder, and guides the push rod to advance and retreat, as well as the liquid tightness between the two cylinders. In particular, a seal member for preventing liquid leakage and a seal member for preventing air suction are incorporated in the inner periphery of the annular seal holding member, and the seal holding member is formed in the housing. The hydraulic fluid is accommodated in the recess and is disposed through a plate disposed at the opening of the recess. It is obtained by fixing the body of Kushirinda.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of a clutch booster provided with a push rod guide according to an embodiment of the present invention. The clutch booster includes a power cylinder 2, a hydraulic cylinder 4, a control valve 6, It has.

The power cylinder 2 has a power piston 10 slidably fitted in a cylinder shell 8. The power piston 10 partitions the inside of the cylinder shell 8 into a pressure chamber 12 and an atmosphere chamber 14. ing. A push rod 16 is connected to the shaft center of the power piston 10 and moves forward and backward integrally. The power piston 10 is provided in the atmosphere chamber 14.
It is urged to the pressure chamber 12 side by a return spring 15 disposed inside, and is stopped at the inoperative position shown in FIG.

The connection structure between the power piston 10 and the push rod 16 will be described. At the center 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 in FIG. 1 is referred to as the front), a push rod connecting portion 10a protruding in a cylindrical shape is formed. In the bottomed hole 10b of the shape connecting portion 10a,
The rear end of the push rod 16 is connected via the push rod holding member 11.

The push rod holding member 11 has a cup-shaped portion 11a and a flange 11b formed on the opening side (right side in the figure) as shown in an enlarged view in FIG. An annular groove 11c is provided on the inner peripheral surface of the portion 11a. A chamfered portion 11d is formed on a wall surface of the annular groove 11c on the opening side. On the other hand, an annular groove 16 a is also formed on the outer peripheral surface of the end of the push rod 16. The wiring 13 is simultaneously engaged in both the annular grooves 11c and 16a of the push rod holding member 11 and the push rod 16, thereby connecting the push rod 16 and the push rod holding member 11.

A female screw is formed on the inner peripheral surface of the bottomed hole 10 b of the power piston 10, and a male screw is formed on the outer peripheral surface of the push rod holding member 11. The push rod holding member 11 and the push rod 16 connected to the holding member 11 are fixed to the power piston 10 by being screwed into the bottom hole 10b. With the push rod holding member 11 screwed into the hole 10b of the power piston 10 as described above, the flange 11b of the push rod holding member 11 comes into contact with the distal end surface of the cylindrical connecting portion 10a of the power piston 10. ing.

Further, a small cup seal 2 is provided on a sliding portion of the outer periphery of the power piston 10 with the cylinder shell 8.
1 and the wear ring 23 are fitted. By using such a small cup seal 21, the sliding resistance can be reduced without lowering the durability and airtightness of the seal member, and the operation feeling of the clutch pedal can be improved.

The hydraulic cylinder 4 is provided on a cylinder body 20 connected and fixed to a housing 18 for closing an opening of the cylinder shell 8. An O-ring 19 is interposed between the housing 18 and the cylinder body 20. Cylinder hole 20 of cylinder body 20
A hydraulic piston 22 is slidably disposed in a. The hydraulic piston 22 divides the inside of the cylinder hole 20a into a hydraulic chamber 24 on the power cylinder 2 side and an atmosphere chamber 26 on the distal end side. Liquid tightness and airtightness between 24 and 26 are maintained.

A push rod 16 connected to the power piston 10 has a push rod guide (denoted by reference numeral 28 as a whole) held at the center of a housing 18.
And extends toward the hydraulic cylinder 4 side. The housing 18 includes the air chamber 1 of the power cylinder 2.
4 and is provided with a recess 18c having a through hole 18b formed in the bottom surface.
The push rod guide 28 is housed therein.
The push rod guide 28 is provided on the annular seal holding member 2.
9 and a seal member 31 for preventing liquid leakage incorporated in annular concave portions formed at both ends of the inner surface of the seal holding member 29.
And a seal member 33 for preventing air suction.
These two seal members 31, 33 are made of Y packing. Further, the seal holding member 29 is made of resin. The annular seal holding member 29 has an inner diameter substantially matching the outer diameter of the push rod 16 and an outer diameter substantially matching the inner diameter of the recessed portion 18c of the housing 18. Mated,
A push rod 16 penetrates the inner peripheral portion. A seal member (O-ring) is provided on the outer periphery of the seal holding member 29.
37 is fitted to maintain liquid tightness and air tightness on the outer peripheral side of the push rod guide 28.

The push rod guide 28 is fixed by attaching a ring plate 39 to the entrance side of the recess 18 c of the housing 18 and pressing the ring plate 39 by the end of the cylinder body 20 fixed to the housing 18. The air suction preventing seal member 33 incorporated in the seal holding member 29 is prevented from falling off by the inner peripheral portion of the bottom surface of the concave portion 18c of the housing 18, while the liquid leakage preventing seal member 31 is connected to the ring plate. 39 prevents the slipping out.

Push rod guide 2 according to this embodiment
In the configuration of No. 8, the number of components is greatly reduced and the structure is simplified as compared with the configuration of the conventional guide portion. In addition, troublesome operations such as press-fitting of an oil seal and installation of a snap ring are eliminated, and assemblability is improved. Further, since the seal members 31 and 33 are made of Y packing and the seal holding member 28 is made of resin, cost can be reduced. Moreover, the retaining members 31 and 33 are prevented from coming off.
This is performed by the housing 18 and the ring plate 39, and the reliability is improved because the snap ring is not used.

The distal end of the push rod 16 penetrating through the push rod guide 28 is connected to a hydraulic piston 22 slidably fitted in the cylinder body 20. An insertion hole 22a having an inner diameter slightly larger than the outer diameter of the push rod 16 is formed on the end surface of the hydraulic piston 22 on the power cylinder 2 side (see FIG. 3 showing a connecting portion in an enlarged manner). Hole 22a
The tip of the push rod 16 is inserted therein. An annular groove 22 b is formed on the inner peripheral surface of the insertion hole 22 a of the hydraulic piston 22, while an annular groove 16 b is also formed on the outer peripheral surface of the distal end portion of the push rod 16. A chamfered portion 22c is formed on the wall surface on the opening side (left side in FIG. 3) of the inner peripheral annular groove 22b of the hydraulic piston 22. A wire ring 41 is fitted in these two annular grooves 22b, 16b, and engages with the push rod 16 and the hydraulic piston 22 simultaneously, so that both of them are engaged.
22 are connected. The inclination angle of the chamfered portion 22c is set to an angle such that the push rod 16 comes out when a load equal to or more than a predetermined value is applied.

The wiring 41 has a shape in which a part of a substantially circular ring is cut and has a length of about three quarters in a free state. As shown in FIG. 4, the wiring 41 is slightly deformed, and the diameter D ₂ in the direction orthogonal to the diameter D ₁ (the vertical direction in FIG. 4) of the portion having the cut portion 41a is slightly shifted on both sides. It is enlarged. Therefore,
When this wiring 41 is fitted into both annular grooves 16b and 22b, it does not engage with the annular groove 22b of the hydraulic piston 22 over the entire circumference, but engages only at two places 41b and 41c on both sides. (See FIG. 5). As described above, the annular groove 22b of the hydraulic piston 22 is formed with the chamfered portion 22c having a predetermined angle, and the wiring 39 is partially formed on the annular groove 22b of the hydraulic piston 22 instead of the entire circumference, but in part 41b, 41c. However, the push rod 16 does not come out of the hydraulic piston 22 at a withdrawal load less than a predetermined value. It can be removed from the hole 22a.

A push rod 47 for operating a clutch is in contact with the front surface (the end surface on the side of the atmosphere chamber 26) of the hydraulic piston 22. Further, the other end of the clutch operating push rod 47 is connected to a clutch outer lever (not shown).

The control valve 6 includes a housing 18
And, it is provided in valve holes 18a, 30a formed in a valve housing 30 fixed to the housing 18. A valve lifter 32 is provided in the valve hole 30a.
Are slidably fitted. On the housing 18 side of the valve lifter 32, a diaphragm 43 is provided.
It is clamped between the step on the inner surface of a and the annular retainer 45. The valve lifter 32 has a medium diameter portion 32 a slidably supported in a valve hole 30 a of the valve housing 30.
And a small-diameter portion 32c penetrating through the inside of the annular retainer 45, and a large-diameter portion 32b intermediate the small-diameter portion 32c. The inside of the valve holes 18a, 30a is partitioned into a hydraulic chamber 34, an exhaust chamber 35, and a variable pressure chamber 36 by the diaphragm 43 and the sealing member 49 on the outer periphery of the valve lifter 32.

The valve lifter 32 is constantly urged toward the hydraulic pressure chamber 34 by a spring 38 disposed in the variable pressure chamber 36. When the valve lifter 32 is not operated, the large diameter portion 32b hits the annular retainer 45 and stops. When the hydraulic pressure from the master cylinder is introduced into the
To move to the right in FIG. An axial and radial passage 32 d is formed in the valve lifter 32, and one end of the internal passage 32 d is connected to the variable pressure chamber 3.
Opened at the end on the 6th side, the other end is opened in the exhaust chamber 35, and is open to the atmosphere via an exhaust cover (not shown).

The valve hole 30 of the valve housing 30
a, the poppet valve 42
Are slidably disposed. This poppet valve 42
The head 42a faces the valve lifter 32 with a small diameter portion 30b formed in the valve hole 30a. A cap 44 is inserted into the opening side of the valve hole 30a, and is fixed by a 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 is slidably fitted on the inner peripheral surface of the cap 44 so that the poppet valve 42 is guided to move forward and backward. O-rings 48 and 50 are fitted on the outer peripheral surface of the shaft portion 42b of the poppet valve 42 sliding on the inner peripheral surface of the cap 44 and the outer peripheral surface of the cap 44 fitted on the inner peripheral surface of the valve hole 30a, respectively. Thus, the airtightness between the air pressure chamber 52 inside the valve hole 30a and the outside of the valve hole 30a is maintained.

A spring 54 is interposed between the back side (the right side in the figure) of the head 42a of the poppet valve 42 and the tip end surface of the cap 44 to urge the poppet valve 42 toward the valve lifter 32. When the control valve 6 is not operated, the head 42a of the poppet valve 42 urged by the spring 54 engages the small diameter portion 3 of the valve hole 30a.
0b is seated on a valve seat 56 formed on the side surface. When the poppet valve 42 is seated on the valve seat 56, an air tank (not shown) is provided through the compressed air supply port 58.
Is disconnected from the air pressure chamber 52 connected to the pressure change chamber 36. Although the poppet valve 42 is made of metal in the conventional configuration, it is made of resin in this embodiment. By making the poppet valve 42 resin, the weight can be reduced and the cost can be reduced.

The compressed air supply port 58 of the control valve 6 is connected to an air tank (not shown), and the variable pressure chamber 36 is connected to the supply port 30 of the valve housing 30.
The pressure chamber 12 is connected to the pressure chamber 12 of the power cylinder 2 via a pipe 66 and a pipe 66.

The hydraulic chamber 34 of the control valve 6 communicates with the hydraulic chamber 24 of the hydraulic cylinder 4 through a passage 60 formed in the housing 18. The opening 62 communicates with an inlet port 64 by a passage 62 formed at the end. Further, the inlet port 64 of the housing 18 is connected to an output pressure chamber of a master cylinder (not shown) operated by a clutch pedal.

The end (rear end) of the cylinder body 20 is connected to the hydraulic passage 6 formed in the housing 18.
0, 62, but the hydraulic fluid sent from the master cylinder is
Hydraulic chamber 24 and hydraulic chamber 34 of control valve 6
The passage grooves 20b and 20c are formed to supply the air to the air passage. The shape and size of these passage grooves 20b and 20c can be set as appropriate. In particular, it is preferable that the passage groove 20b on the master cylinder side has a sufficiently large passage area from the viewpoint of responsiveness. The passage groove 20c on the control valve 6 side preferably has a small sectional area so as to have 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. When a clutch pedal (not shown) is depressed, the liquid in the output pressure chamber of the master cylinder
8 through the passage 62 and the passage groove 20 b of the cylinder body 20 from the inlet port 64 of the hydraulic cylinder 4.
Is sent to the hydraulic chamber 24 of the control valve 6 through the passage groove 20c and the passage 60. Accordingly, the hydraulic piston 22 is pressed rightward in FIG. 1, and the valve lifter 32 is moved rightward in the figure via the diaphragm 43.

When the valve lifter 32 moves, first, the tip of the valve lifter 32 comes into contact with the head 42a of the poppet valve 42, and the passage 32 inside the valve lifter 32 is moved.
d is closed, and the valve lifter 32 further moves to move the poppet valve 42 away from the valve seat 56. When the poppet valve 42 is separated from the valve seat 56, the air pressure chamber 52 communicating with the compressed air supply port 58 and the variable pressure chamber 36 are connected. Then, the compressed air in the air tank is released from the air pressure chamber 52.
From the pressure chamber 12 of the power cylinder 2
Supplied to The compressed air supplied to the pressure chamber 12 moves the power piston 10 to the right in FIG. When the power piston 10 advances, the push rod 16 and the hydraulic piston 22
Move integrally to the right in FIG. 1 to move the clutch operating push rod 47 forward. As the clutch operating push rod 47 advances, the clutch outer lever operates to disengage the clutch.

When the depression force of the clutch pedal is released, the pressure in the hydraulic chamber 34 of the control valve 6 decreases, and the valve lifter 32 returns to the state shown in FIG. Then, the internal passage 32d of the valve lifter 32 is opened, and the variable pressure chamber 36 is communicated with the exhaust chamber 35 via the internal passage 32d, and the air in the pressure chamber 12 of the power cylinder 2 flows through the pipe 66, the variable pressure chamber 36, and the internal passage. 32d, is discharged to the atmosphere via 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 outer lever returns, and the clutch is connected again.

Incidentally, the shapes of the seal holding member, the seal member, the ring plate, the recessed portion of the housing, the cylinder body, and the like constituting the push rod guide are not limited to those shown in the drawings, but have the same functions. It is needless to say that can be appropriately selected.

[0034]

As described above, according to the present invention, the power piston is operated by the compressed air introduced into the pressure chamber of the power cylinder, and the output of the power piston is transmitted through the push rod connected to the power piston. A push rod mounted on a housing that separates the power cylinder and the hydraulic cylinder of the clutch booster that transmits the piston to the piston, guides the advance and retreat of the push rod, and maintains liquid tightness and air tightness between the two cylinders. In the guide, a seal member for preventing liquid leakage and a seal member for preventing suction of air are assembled on the inner periphery of the annular seal holding member, and the seal holding member is housed in a recess formed in the housing. Through the plate arranged in the opening of the hydraulic cylinder body By was boss, to reduce the push rod guide parts, it is possible to simplify the structure. Further, there is no need to perform operations such as press-fitting of an oil seal and installation of a snap ring, so that assemblability is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a clutch booster provided with a push rod guide according to one embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a coupling structure between a power piston and a push rod of the clutch booster.

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

FIG. 4 is a view showing an example of a wiring used for connecting a push rod to a power piston and a hydraulic piston.

FIG. 5 is a diagram illustrating an engagement state of the wiring.

FIG. 6 is a sectional view of a main part (push rod guide) of a conventional clutch booster.

FIG. 7 is a sectional view showing another example of a conventional push rod guide.

[Explanation of symbols]

 2 Power cylinder 4 Hydraulic cylinder 10 Power piston 12 Pressure chamber 16 Push rod 18 Housing 18c Concave portion of housing 20 Hydraulic cylinder body 20b Liquid passage 20c Liquid passage 22 Hydraulic piston 28 Push rod guide 29 Seal holding member 31 Liquid leakage Sealing member for prevention 33 Sealing member for preventing air suction 37 Sealing member (O-ring) 39 Plate

Claims (6)

[Claims] 1. A clutch booster for operating a power piston by compressed air introduced into a pressure chamber of a power cylinder and transmitting the output to a piston of a hydraulic cylinder via a push rod connected to the power piston. A push rod guide mounted on a housing that separates the power cylinder and the hydraulic cylinder, guides the push rod forward and backward, and maintains liquid tightness and air tightness between the two cylinders. In addition, a seal member for preventing liquid leakage and a seal member for preventing suction of air are assembled, the seal holding member is housed in a recess formed in the housing, and via a plate arranged in the opening of the recess,
A push rod guide for a clutch booster, wherein the push rod guide is fixed by a body of the hydraulic cylinder. 2. The push rod guide for a clutch booster according to claim 1, wherein a seal member is mounted on an outer periphery of the seal holding member. 3. A plate in which a seal member for preventing liquid leakage and a seal member for preventing air suction held by a seal holding member are interposed between an inner peripheral portion of a housing and the seal holding member and the cylinder body. The push rod guide of the clutch booster according to claim 1 or 2, wherein each of the push rod guides is prevented from coming off. 4. The push rod guide for a clutch booster according to claim 1, wherein the seal member for preventing leakage of liquid and the seal member for preventing suction of air are Y packing. 5. The push rod guide for a clutch booster according to claim 1, wherein the seal holding member is made of resin. 6. The push rod guide for a clutch booster according to claim 3, wherein a liquid passage is formed at a tip of a cylinder body for holding the plate.