A method for manufacturing a rod includes a step of preparing a hollow first member and a second member formed so as to have a portion smaller in outer diameter than an outer diameter of the first member, a restraining step of placing a restraining member into abutment with an outer peripheral surface of the first member, a step of moving an inner peripheral surface of the first member and an outer peripheral surface of the second member closer to each other while rotating at least one of the first member or the second member, and a step of joining the first member and the second member by welding with the aid of friction by axially pressing in the first member and the second member by a predetermined amount after placing the inner peripheral surface of the first member and the outer peripheral surface of the second member into contact.

A hydraulic damper includes: a cylinder extending from one side to the other side and containing liquid; a rod configured to move relative to the cylinder; a first piston configured to move relative to the cylinder inside the cylinder along with relative movement of the rod and generate damping force; a first elastic member inside the cylinder and configured to be displaced along with relative movement of the rod; a second elastic member separate from the first elastic member inside the cylinder and configured to be displaced along with relative movement of the rod; and a second piston separate from the first piston and configured to move relative to the cylinder inside the cylinder, to be always supported by the first and second elastic members so as to be movable inside the cylinder, and to generate damping force that varies according to displacement of the first and second elastic members.

Disclosed is a frequency sensitive type shock absorber including a piston rod reciprocating an inside of a cylinder and having a connection passage therein; a piston valve mounted on the piston rod and having a plurality of compression and rebound flow paths penetrating up and down thereof, and partitioning the cylinder into compression and rebound chambers; and a valve assembly mounted on the piston rod to generate a damping force that changes with frequency during a rebound stroke; wherein the valve assembly comprises: a housing coupled to the piston rod and having a pilot chamber in communication with the connection passage; a main retainer coupled to the piston rod and having a main chamber formed on an upper portion thereof in communication with the connecting passage; and a pilot valve coupled to the piston rod and disposed between the housing and the main retainer to partition the pilot chamber and the main chamber.

A combination gas spring and shock absorber apparatus includes a vented gas spring housing and a vented shock absorber housing slidably mounted within the gas spring housing. A shock absorber piston is concentrically mounted within a gas spring piston. A base housing is slidably mounted in the gas spring housing. A shaft extends through the base housing and into the shock absorber housing. The shock absorber piston is mounted in the shock absorber housing on the free end of the shaft. The gas spring piston is mounted in the gas spring housing on the distal end of the base housing. The shock absorber piston is fluidically sealed and slides within the shock absorber housing. The gas spring piston is fluidically sealed and slides along the gas spring housing and the shock absorber housing. The base housing telescopically translates relative to the gas spring housing.

An air spring for a cab of a heavy truck with automatic height adjustment, in which the air spring is provided between the cab and a frame of a truck and supports the cab with a pressure of air filling in the air spring, includes a canister in which an internal space is formed, and a piston movably mounted in the internal space of the canister and configured to ascend and descend relative to the canister. A port opening unit is provided adjacent to an intake port and an exhaust port of the piston, respectively. When the cab ascends or descends, each of the port opening units comes into contact with guides, each having an inclined surface, formed in the canister to open either the intake port or the exhaust port.

This cylinder device of the present aspect includes: a cylinder having a bottomed tubular shape; a seal member provided at an opening of the cylinder; and a piston rod that is provided to protrude from the opening of the cylinder and slides with respect to the seal member. A sliding surface of the piston rod has a chrome-plated layer. In the sliding surface, as characteristic evaluation parameters of a plateau structure surface described in JIS B 0671-2 and ISO 13565-2, a reduced valley depth Rvk is 0.06 μm or more and less than a plating thickness, a reduced peak height Rpk is 0 μm or more and 0.04 μm or less, and a core roughness depth Rk is 0.08 μm or more and 0.16 μm or less.

A shock absorber is provided with a cylinder, a piston inserted into the cylinder and demarcating an interior of the cylinder into an extension side chamber and a compression side chamber, a piston rod joined to the piston, a damping passage, provided in the piston rod, that communicates with the extension side chamber and the compression side chamber, and a damping force adjustment valve provided in the damping passage. The damping force adjustment valve includes a damping force adjustment unit and a solenoid that drives the damping force adjustment unit to adjust a flow channel resistance. The piston rod includes a yoke into which the damping force adjustment valve is inserted, and a piston holding member mounted on the yoke. The yoke includes a through-hole opening from a side of the yoke and leading to the interior, and a groove provided on a perimeter of the yoke, extending from an anti-piston end, and leading to the through-hole.

A shock absorber includes a hard-side damping element for applying resistance to a flow of liquid from a compression side chamber to an extension side chamber, a solenoid valve capable of changing an opening area of a compression side bypass passage for communicating the compression side chamber and the extension side chamber by bypassing the hard-side damping element, and a soft-side damping element provided in the compression side bypass passage in series with the solenoid valve. The hard-side damping element has an orifice and a leaf valve provided in parallel with the orifice. The soft-side damping element has an orifice having an opening area larger than that of the orifice.

In a cylinder device, a rod of which one end portion is joined to a piston in a cylinder and the other end portion protrudes from an opening portion of the cylinder includes a first member that is a hollow cylindrical member in sliding contact with a sliding contact member, and a second member that does not come into sliding contact with the sliding contact member. An outer diameter of at least a first member side end portion of the second member is smaller than an outer diameter of the first member. An inner peripheral portion of the first member is joined to an outer peripheral portion of the second member by friction weld joining.

A shock absorber for a wheel suspension of a vehicle may include an outer cylinder, an outer piston that is axially displaceably guided in the outer cylinder, an inner piston that is axially displaceably guided in the outer piston, and a piston rod that is connected to the inner piston and that is guided out of the outer piston. A surface, which is located remote from the piston rod, of a piston portion of the outer piston, which is axially displaceably guided on an inner lateral surface of the outer cylinder, is connected so as to communicate partially with surroundings of the shock absorber.