JPH09177720A - Attaching mechanism for piston in fluid pressure cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an attaching mechanism for a piston, excellent in assemblage and maintenance performance by turning headed bolts respectively screwed to a plurality of thread holes, and bringing the inner ends in pressure-contact with the outer end surface of a piston. SOLUTION: A piston 2 is fitted around the outer periphery of a piston rod 3, and a piston nut 4 in which headed bolts 11 are previously screwed to respective thread holes 4b is screwed to an external thread 6 of the piston rod 3. In this case, the piston nut 4 is so screwed that a clearance larger than the heights of head parts 11a of the headed bolts 11 may be formed between the inner end surface and the outer end surface 2a of the piston 2. After that, the head parts 11a of respective headed bolts 11 are sequentially gripped by a tool such as a wrench and turned in such a direction that the headed bolts 11 are to be advanced from the threaded holes 4b. Therefore, the head parts 11a of respective headed bolts 11 are brought in contact with the outer end surface 2a of the piston 2, the surface pressure C is generated on the contact surface of the head parts 11a with the outer end surface 2a of the piston 2, the axial force T is generated on the piston rod 3, and the piston 2 is firmly fixed to the piston rod 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston mounting mechanism for a fluid pressure cylinder such as a hydraulic cylinder or a pneumatic cylinder used in construction machinery.

[0002]

2. Description of the Related Art An example of a conventional mounting mechanism of this type is shown in FIG. In FIG. 2, 1 is a cylinder, 2 is a piston fitted in the cylinder 1 so as to be reciprocally movable, 3 is a piston rod, and 4 is a piston nut.

The piston nut 4 is screwed into a male screw 6 formed at the end of the piston rod 3. Reference numeral 5 is a nylon ring for stopping the rotation of the piston nut 4.

When the piston nut 4 is tightened with a predetermined torque, an axial force T acts on the piston rod 3, and a surface pressure C is generated between the inner end surface 7 of the piston nut 4 and the outer end surface 8 of the piston 2. However, the piston nut 4 is prevented from being loosened by the axial force T and the frictional resistance of the nylon ring 5.

[0005]

In the above-mentioned conventional mounting mechanism, in order to prevent loosening of the piston nut 4 and to generate the axial force T for firmly fixing the piston 2 to the piston rod 3, , Requires a large tightening torque. Therefore, there is a problem that a large tightening device is required and a large number of man-hours are required for assembling the fluid pressure cylinder.

An object of the present invention is to provide a piston mounting mechanism which can obtain a large axial force with a relatively small tightening torque and is excellent in assemblability and maintainability.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is that a piston that reciprocates in a cylinder is fitted to the outer circumference of a piston rod, and a piston nut is screwed onto a male screw formed on the piston rod. In the fluid pressure cylinder described above, a plurality of screw holes are formed in the piston nut in parallel with the screw hole at the center of the piston nut, and headed bolts respectively screwed into the plurality of screw holes are rotated to thereby The piston mounting mechanism in a fluid pressure cylinder is characterized in that the end is pressed against the outer end surface of the piston.

Therefore, a predetermined axial force is generated by rotating a headed bolt screwed into a plurality of screw holes formed in the piston nut and pressing its inner end against the outer end surface of the piston. .

[0009]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the invention is shown in FIG. In FIG. 1, 1 is a cylinder, 2 is a piston that is reciprocally fitted in the cylinder 1, 3 is a piston rod, 4 is a piston nut, and it is screwed onto a male screw 6 formed at the end of the piston rod 3. Have been combined.

The piston nut 4 has a screw hole 4a at the center thereof.
A plurality of (for example, 12) screw holes 4b extending in parallel with are formed at equal intervals along the circumferential direction. Reference numeral 11 is a headed bolt having a hexagonal head portion 11a, and its screw portion 11b is screwed into each screw hole 4b so that the inner end surface of the head portion 11a can abut on the outer end surface 2a of the piston 2. .

Then, the piston 2 is replaced with the piston rod 3
Then, the piston nut 4 with the headed bolts 11 screwed into the respective screw holes 4b is fitted to the piston rod 3
It is screwed into the male screw 6 of. At this time, the piston nut 4 has a headed bolt 11 between the inner end surface and the outer end surface 2a of the piston 2.
Screw in so that a gap greater than or equal to the height of the head 11a is formed.

After that, the heads 11a of the headed bolts 11 are sequentially gripped by a tool such as a spanner and a wrench, and the headed bolts 11 are rotated in the direction of advancing from the screw holes 4b. As a result, the head portion 11a of each headed bolt 11 contacts the outer end surface 2a of the piston 2, and the surface pressure C is applied to the contact surface between the head portion 11a and the outer end surface 2a of the piston 2.
Occurs, an axial force T is generated on the piston rod 3, and the piston 2 is firmly fixed to the piston rod 3.

Thus, by rotating the plurality of headed bolts 11 with a torque smaller than that of the conventional one by using a tool such as a wrench or a wrench, the same axial force T as the conventional one can be obtained.
Therefore, the piston 2 can be firmly fixed to the piston rod 3.

Although the above embodiment has been described with reference to the hydraulic cylinder, it can be applied to all fluid pressure cylinders such as a pneumatic cylinder. Also, attach the headed bolt 11 to the piston nut 4
Can be screwed into the screw hole 4b from the left side, and the tip of the screw portion 11b can be brought into contact with the outer end surface of the piston 2.

[0015]

According to the present invention, since the piston is fixed to the piston rod by rotating each of the plurality of headed bolts, the rotating torque of each headed bolt can be smaller than that of the conventional one.

Therefore, unlike the conventional one, a large-sized tightening device is not required and the number of assembling steps is reduced, so that the piston can be easily maintained and replaced, and a fluid pressure cylinder excellent in assemblability and maintainability can be provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of a piston mounting mechanism in a fluid pressure cylinder according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a conventional mounting mechanism. is there.

[Explanation of symbols]

 1 Cylinder 2 Piston 2a Outer end face 3 Piston rod 4 Piston nut 4a Center screw hole 4b Screw hole 11 Headed bolt

Claims (1)

[Claims] 1. A fluid pressure cylinder comprising a piston reciprocating in a cylinder fitted on the outer circumference of a piston rod, and a piston nut screwed onto a male screw formed on the piston rod. A plurality of screw holes are bored in parallel with the screw holes of, and the inner end of the bolt is screwed into the outer end face of the piston by rotating the headed bolts screwed into the plurality of screw holes. Piston mounting mechanism in the characteristic fluid pressure cylinder.