| 主权项 |
1. A fluid pressure shock absorber comprising:
a cylinder sealingly containing fluid; a piston slidably disposed in the cylinder; and a piston rod coupled with the piston, the piston rod having one end thereof extending to an outside of the cylinder, wherein the piston includes extension-side communication passages and compression-side communication passages, and has a first disk valve for generating damping forces by opening and closing one of the extension-side communication passages and the compression-side communication passages and a second disk valve for generating damping forces by opening and closing the other of the extension-side and compression-side communication passages; the piston includes a first piston body and a second piston body coupled to each other at coupled surfaces thereof, the coupled surfaces extend in a direction parallel to a radial direction of the piston rod, and the coupled surfaces of the first piston body and the second piston body contact each other or are opposed to each other; a first through-hole, which the piston rod penetrates through, is provided at the first piston body; the extension-side and compression-side communication passages are provided at the first piston body; a second through-hole, which the piston rod penetrates through, is provided at the second piston body; the extension-side and/or the compression-side communication passages are provided at the second piston body; an annular valve seat, which the second disk valve abuts against, is formed on a non-coupled surface of the second piston body, and the other of the extension-side and compression-side communication passages are in communication with an inner circumference of the annular valve seat; a rotation preventing unit for preventing relative rotation of the piston bodies is provided on the coupled surfaces of the piston bodies, the rotation preventing unit being configured such that the extension-side communication passages of the first piston body are aligned with the extension-side communication passages of the second piston body and/or the compression-side communication passages of the first piston body are aligned with the compression-side communication passages of the second piston body; the rotation preventing unit comprises, at one of the first and second piston bodies, a plurality of first recesses arranged in the circumferential direction of one of the first and second piston bodies and a plurality of first protrusions formed between the first recesses, and the rotation preventing unit further comprises, at the other of the first and second piston bodies, a plurality of second protrusions arranged in the circumferential direction of the other of the first and second piston bodies and a plurality of second recesses formed between the second protrusions; the second protrusions and the first protrusions are fitted into the first recesses and the second recesses, respectively, without press-fitting, to prevent the relative rotation of the piston bodies; the first recesses are recessed from the coupled surface of the one of the first and second piston bodies in an axial direction of the piston rod; the second protrusions protrude from the coupled surface of the other of the first and second piston bodies in an axial direction of the piston rod; the radially inner circumferences of the first recesses and the second protrusions are facing the through-holes of the piston bodies; one of the first protrusions and the second protrusions is substantially circumferentially tightly fitted into the second recesses or the first recesses, the rest of the first protrusions and the second protrusions are inserted into the second recesses or the first recesses with spaces therebetween in the circumferential direction; and the first piston body, the second piston body, and the first and second disk valves are fixed to the piston rod, with the first protrusions being engaged with the second recesses and the second protrusions being engaged with the first recesses. |
