JP2000035057A - Connecting structure between power piston for clutch booster and push rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure and improve the operation responsiveness of a clutch booster by reducing the number of components of a connecting part between a power piston and a push rod. SOLUTION: A power piston 10 is actuated by air introduced into a pressure chamber 12 of a power cylinder 2 and this output is transmitted to a piston 22 of a hydraulic cylinder 4 via a push rod 16 connected to the power piston 10. A cylindrical connecting part 10a is provided in the frontal center part of the power piston 10 and a bottomed hole 10b is formed in its inside. A cup- shaped push rod holding member 11 is fitted and connected to the end of the push rod 16 and the holding member 11 is threadly engaged and fixed to the bottomed hole 10b. This constitution can reduce the number of components, reduce the volume of the pressure chamber 12 in non-actuating time, and improve the operation responsiveness of the power piston 10.

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 power piston and a push rod connected to a front surface of the power piston and transmitting an output of the power piston to a hydraulic piston. It is about structure.

[0002]

2. Description of the Related Art Generally, a clutch booster is controlled by operating a clutch pedal to supply and discharge compressed air to and from a pressure chamber of a power cylinder, and a power valve operated by the compressed air introduced to the pressure chamber. A piston, 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 connecting and disconnecting the clutch by rotating the clutch outer lever.

The push rod is connected to the center of the front surface of the power piston (the surface on the side of the hydraulic cylinder), and is integrally advanced and retracted by the operation of the power piston. The power piston and the push rod are connected by a structure as shown in FIG. That is, the cup-shaped push rod holding member 111 is fitted to the end (the left end in FIG. 7) of the push rod 116, and the most end 11
1c, these push rods 11
6 and the push rod holding member 111 are connected. On the other hand, in the center of the power piston 110, a hole 110c penetrating both surfaces is formed.
The push rod holding member 111 is inserted into Oc, and the push rod 116 and the push rod holding member 111 are fixed to the power piston 110 by screwing the nut 172 through the plate 170. The airtightness between the pressure chamber 112 and the atmosphere chamber 114 is determined by the O-ring 174 fitted between the through hole 110 c of the power piston 110 and the push rod holding member 111.
Is held by

[0004]

As described above, the conventional clutch booster has a power piston 110 in which a through hole 11 is formed.
0c, and the push rod 11 is formed in the hole 110c.
6 and the push rod holding member 111 are inserted, so that an O-ring 174 is required to maintain the airtightness between the pressure chamber 112 and the atmosphere chamber 114. Further, a plate 170 and a nut 172 are required to fix the push rod holding member 111 to the power piston 110, and the number of parts is large and the structure is complicated. In addition, since the tip of the push rod holding member 111 inserted through the through hole 110c of the power piston 110 protrudes toward the pressure chamber 112, the volume of the pressure chamber 112 when the power piston 110 is not operated is increased, and the loss volume is reduced. Due to the large size, when the clutch booster is operated, extra air must be supplied by the amount corresponding to the loss volume, and there is a problem that the operation responsiveness is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a connection structure between a power piston and a push rod of a clutch booster which can reduce the number of parts and simplify the structure. It is intended for. It is another object of the present invention to provide a connection structure between a power piston and a push rod, which can reduce the non-operating capacity of the pressure chamber of the power cylinder and improve the operation responsiveness.

[0006]

In a clutch booster according to the present invention, a power piston and a push rod are connected to each other by an air introduced into a pressure chamber of a power cylinder. A clutch booster transmitting to a piston of a hydraulic cylinder via a push rod connected to
A bottomed hole is formed in the front surface of the power piston, and the end of the push rod is inserted into this hole and connected.

[0007]

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 connection structure between a power piston and a push rod according to an embodiment of the present invention. The clutch booster includes a power cylinder 2 and a hydraulic cylinder. 4 and a control valve 6.

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. The angle of inclination of the chamfered portion 11d is set such that the push rod 16 comes out when a load equal to or greater than a predetermined value is applied.

Since the wiring 13 has the same configuration as a wiring 41 for connecting the push rod 16 and the hydraulic piston 22, which will be described later, FIG.
This will be described with reference to FIG. The wiring 13 is
A part of a substantially circular ring is cut, and has a shape having a length of about three-quarters of a circumference in a free state. And FIG.
As shown in, Yes and is slightly deformed, it is expanded in the direction of diameter D ₂ which is perpendicular than (vertical direction in FIG. 4) part of the diameter D ₁ having a cutting portion slightly on both sides. Therefore, when the wiring 13 is fitted into both the annular grooves 11c and 16a, it does not engage with the annular groove 11c of the push rod holding member 11 over the entire circumference, but is provided at two places on both sides (reference numerals 41b and 41b in FIG. 5).
41c). Note that FIG. 4 is exaggerated for easy understanding of the deformed state of the wiring 41.

As described above, the push rod holding member 11
The annular groove 11c is formed with a chamfered portion 11d at a predetermined angle, and the wiring 13 is hooked on the annular groove 11c of the push rod holding member 11 instead of the entire circumference, but a part thereof. The push rod 16 does not come out of the push rod holding member 11 with the following pulling load, but the push rod 16 can be pulled out of the push rod holding member 11 when a larger load is applied. .

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.

In this embodiment, the push rod 1
6 and the structure of the connecting portion between the push rod holding member 11
Although the structure of the connecting portion between the distal end portion (the right side in FIG. 1) of the push rod 16 and the hydraulic piston 22 described later is the same as that of the conventional clutch booster, the present invention is not limited to such a structure. Similarly, it may be fixed by caulking or the like.

In the conventional configuration shown in FIG. 7, a cup seal 121 is mounted as a seal member on a sliding portion of the outer periphery of the power piston 110 with the cylinder shell 108 so that the space between the pressure chamber 112 and the atmosphere chamber 114 is provided. Although airtightness is maintained, such a cup seal 121 has a problem in that the sliding resistance is large and the air pressure supplied to the pressure chamber 112 pulsates, so that the feeling is not good. Therefore, in this embodiment, the cup seal 21 is downsized, and the wear ring 23 is added. With this configuration, the sliding resistance can be reduced without reducing 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 extends through a guide portion (generally indicated by reference numeral 28) held at the center of the housing 18 to the hydraulic cylinder 4 side. The housing 18 has a recessed portion 18 protruding toward the atmosphere chamber 14 of the power cylinder 2 and having a through hole 18b formed in the bottom surface.
The guide portion 28 is accommodated in the concave portion 18c. The guide portion 28 includes an annular seal holding member 29, a liquid leakage preventing seal member 31 and an air suction preventing seal member 33 incorporated in annular concave portions formed at both ends of the inner surface of the seal holding member 29. ing. 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 that substantially matches the outer diameter of the push rod 16 and an outer diameter that substantially matches the inner diameter of the recessed portion 18c of the housing 18, and is provided in the recessed portion 18c of the housing 18. The push rod 16 penetrates the inner periphery thereof while being fitted. An O-ring 37 is provided on the outer periphery of the seal holding member 29.
Are fitted to maintain liquid tightness and air tightness on the outer peripheral side of the guide portion 28.

The guide portion 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. Seal holding member 2
9 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 seal member 3 for preventing liquid leakage is incorporated.
1 is prevented from falling off by the ring plate 39.

The distal end of the push rod 16 penetrating through the guide portion 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). The tip of the push rod 16 is inserted into the hole 22a. An annular groove 22b is formed in the inner peripheral surface of the insertion hole 22a of the hydraulic piston 22.
On the other hand, an annular groove 16 b is also formed on the outer peripheral surface of the distal end 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 the annular grooves 22b and 16b, and engages with the push rod 16 and the hydraulic piston 22 at the same time to connect the two. 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 of a circumference 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 at a predetermined angle, and the wiring 41 is not partially connected to the annular groove 22b of the hydraulic piston 22 but is formed in a part 41b, 41c. The push rod 16 does not come out of the hydraulic piston 22 with a pulling load less than a predetermined value. It can be removed from the hole 22a.

A push rod 47 for operating the 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 42 a 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 on 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.

In the clutch booster, the push rod holding member 11 fitted and connected to the end of the push rod 16 is screwed into the bottomed hole 10b formed in the center of the front surface of the power piston 10. As a result, since the power piston 10 and the push rod 16 are connected, the nut 172, the plate 170, the O-ring 174 (see FIG. 7), and the like, which are conventionally required, can be eliminated, and the number of parts can be reduced. Thus, the structure can be simplified. Further, since there is no hole 110c penetrating through the power piston 10 as in the conventional configuration, the airtightness at the connection portion with the push rod 16 is further ensured. Further, since there is no portion that penetrates through the power piston 10 and protrudes toward the pressure chamber 12, the volume of the pressure chamber 12 when not in operation can be reduced, and the operation responsiveness of the clutch booster improves.

In this embodiment, since the push rod 16 and the hydraulic piston 22 are connected to each other, a tensile load is applied between the push rod 16 and the push rod holding member 11. High connection strength is required. Therefore, the annular groove 16a of the push rod 16 and the push rod holding member 1
The wiring 13 is engaged with the one annular groove 11c. However, when the push rod 16 and the hydraulic piston 22 are not connected to each other (see FIG. 7 in the related art), no tensile load is applied between the push rod 16 and the push rod holding member 11, so that the configuration is shown in FIG. As described above, the annular grooves 16 respectively formed in both the push rod 16 and the push rod holding member 11
The elastic members 17 such as O-rings may be attached to the insides 11a and 11c to connect them.

In the above embodiment, the push rod 1
The push rod holding member 11 is connected to the end of the power piston 6 and is fixed to the power piston 10 via the holding member 11, but the end of the push rod 16 is directly inserted into the bottomed hole of the power piston 10. It can also be inserted and connected. In this case as well, similarly to the case where the push rod holding member 11 is interposed, the connection by the wire 13 or the connection by the O-ring 17 is possible. In the configuration in which the push rod 16 is directly connected to the power piston 10 as described above, the push rod holding member 11 becomes unnecessary, so that the structure can be further simplified.

[0035]

As described above, according to the present invention, the power piston is operated by the air introduced into the pressure chamber of the power cylinder, and the output of the power cylinder is transmitted through the push rod connected to the power piston. In the clutch booster transmitting to the piston, a bottomed hole is formed in the front surface of the power piston, and the end of the push rod is inserted and connected in this hole, thereby connecting the power piston and the push rod. The number of parts can be reduced, and the structure can be simplified. Also,
Since the push rod does not penetrate the power piston, the airtightness of this part is significantly improved. Further, since the end of the push rod does not protrude toward the pressure chamber of the power cylinder, the volume of the pressure chamber when not operating can be reduced, so that the operation responsiveness of the clutch booster is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a clutch booster provided with a connection structure between a power piston and a push rod according to one embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a connection structure between the power piston and a push rod.

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 diagram showing an example of a wiring used for connecting a power piston and a push rod.

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

FIG. 6 is an enlarged longitudinal sectional view showing another connection structure between the power piston and the push rod.

FIG. 7 is a sectional view of a main part of a conventional clutch booster.

[Explanation of symbols]

 Reference Signs List 2 Power cylinder 4 Hydraulic cylinder 10 Power piston 10b Hole with bottom 11 Push rod holding member 11c Annular groove of push rod holding member 12 Pressure chamber 13 Wiring 16 Push rod 16a Annular groove of push rod 17 Elastic member 22 Hydraulic piston

Claims (5)

[Claims] 1. A clutch booster for operating a power piston by 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 coupling structure between a power piston and a push rod of a clutch booster, wherein a bottomed hole is formed in a front surface of a piston, and an end of a push rod is inserted and coupled into the hole. 2. A push rod holding member having a bottomed cylindrical shape is fitted to and connected to an end of the push rod, and the push rod holding member is screwed into a screw formed on an inner surface of a bottomed hole of the power piston. The connection structure between the power piston and the push rod of the clutch booster according to claim 1, wherein the push rod is connected to the power piston by coupling. 3. The clutch booster according to claim 1, wherein an end of the push rod is directly inserted into a bottomed hole of the power piston to connect the power piston and the push rod. Connection structure between power piston and push rod. 4. An annular groove is formed on the inner surface of the push rod holding member or the inner surface of the hole of the power piston.
An annular groove is formed on the outer peripheral surface of the end of the push rod, and the push rod is connected to a push rod holding member or a power piston via a wire ring simultaneously engaged in both annular grooves. 4. A coupling structure between a power piston and a push rod of the clutch booster according to claim 3. 5. An annular groove is formed on the inner surface of the push rod holding member or the inner surface of the hole of the power piston.
An annular groove is formed in an outer peripheral surface of an end portion of the push rod, and the push rod is connected to a push rod holding member or a power piston via an elastic member which simultaneously engages in both annular grooves. A connection structure between a power piston and a push rod of the clutch booster according to claim 2 or 3.