| 摘要 |
PROBLEM TO BE SOLVED: To improve strength in a piston fastening part with a simple structure without using a special high-strength material for a piston rod of a hydraulic cylinder or applying heat treatment to the piston rod. SOLUTION: In this cylinder, the front end of a piston rod 3 is formed with a male thread part 3d, while a piston 4 has a recess with a bottom formed with a female thread part capable of meshing with the male part 3d of the piston rod 3. A bottom part of the recess is formed with six threaded through- holes open to the recess. After insertion of an insertion part 3c through a cushion ring 30, the female thread part of the recess of the piston 4 is screwed on the male thread part 3d of the piston rod 3 until an end face of the piston rod 3 comes into contact with the bottom part of the recess of the piston 4. In this state, by screwing bolts 22 in the threaded through-holes until the front ends of the bolts 22 abut on the end face of the piston rod 3 and by fastening each the bolt 22 to a specified torque, the piston 4 is fastened to the piston rod 3.
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