Disclosed are seal arrangements in a hydraulic device. The seal arrangement includes a seal channel defining a loop. A seal is seated within the seal channel. A coolant flow passage has a first part intersecting with the seal channel at a first point and a second part intersecting with the seal channel at a second point. The first part of the coolant flow passage is configured to provide hydraulic fluid to the seal channel such that, at the first point, a first portion of the hydraulic fluid flows in a first direction around the loop and a second portion of the hydraulic fluid flows in a second direction opposite to the first direction around the loop. At the second point, the first portion of hydraulic fluid and the second portion of hydraulic fluid are configured to flow into the second part of the coolant flow passage.

In a hydrostatic pressure cylinder, a holding member which holds a magnet is mounted on a piston unit to rotate together with a cylinder tube. The cylinder tube is capable of rotating with respect to a rod cover and a head cover. It is thereby possible to change an attachment position of a magnetic sensor by rotating the cylinder tube.

A piston unit is provided with a piston body; a packing mounted on an outer circumferential portion of the piston body; a holding member having a plurality of magnet holding portions that are arranged along a circumferential direction; a plurality of magnets which are held at intervals in the circumferential direction; a first annular yoke disposed on one side in an axial direction of the plurality of magnets; and a second annular yoke disposed on the other side in the axial direction of the plurality of magnets.

A hydraulic cylinder may include a housing and a rod extending from a working end positioned outside the housing through a rod end of the housing to a piston end positioned within the housing. The hydraulic cylinder may also include a piston arranged on the piston end of the rod and configured to articulate within the housing. The hydraulic cylinder may also include a cap end secured to the housing and having a pocket for receiving a sensor. The pocket may have a cylindrical sidewall. The cap end may include a bore extending therethrough and arranged generally tangential to the sidewall where the bore extends into the cap end, breaches the sidewall, and extends further passed the pocket. The hydraulic cylinder may also include a retention pin configured for placement in the bore and for an interference fit with the sensor when the sensor is arranged in the pocket.

A piston and cylinder unit (1) of a working machine, for example a wheel loader, excavator, tipper, crane or stacker or a lifting platform serves to steer, support, extend, pivot, lift or other movements of the working machine or of a tool or a different part of the working machine. The piston and cylinder unit (1) includes a cylinder (2), a piston (7) being arranged in the cylinder (2) to be axially movable and a piston position detection unit (28) detecting the axial position of the piston (7) in the cylinder (2) by high frequency technology. The piston position detection unit (28) includes a housing (3) and an electronic unit being arranged in the housing is arranged in a mounting bore (27) extending radially in the cylinder (2). The piston position detection unit (28) is arranged in the mounting bore (27) such that the interior (3) of the cylinder (2) is sealed from the surroundings of the piston and cylinder unit (1) by the housing (29).

A fluid pressure cylinder has a sensor attachment tool mounted thereon. A holder holds the position sensor in a rail structure extending in an axial direction of a cylinder tube and is secured by screwing to a rod cover or a head cover in an arm part provided to one end of the holder.

The invention relates to a hydraulic cylinder comprising a body (1) having a wall (3) that defines a cylindrical cavity (2), with a cylindrical cavity axis (X), in which a piston (4) is movably mounted, said piston (4) separating said cylindrical cavity (2) into two tight chambers (5, 6) that are isolated from each other, the wall (3) of the body comprising at least two passages (7, 8) for introducing or discharging a fluid into each of said two chambers (5, 6). The cylinder also comprises two end walls (17, 18) and a rigid rod (32) which is secured to the piston (4) and coaxial with the cylindrical cavity (2), said rod (32) passing through a passage opening (20) provided in one of the two end walls (17, 18). The cylinder is characterised in that it comprises a position sensor (38) comprising a sensor head (39), a sensor rod (40) which is secured to the sensor head (39) and around which a magnet (41) is fitted, and a connector (42) connected to said sensor head (39).

A connection device for connecting an electrical or electronic component, which is accommodated in a thick-walled housing part, through a stepped bore in the wall of the housing part, includes a connection part having a stepped cylindrical body having a first cylindrical portion with a first outer diameter corresponding to the diameter of an inner bore portion of the stepped bore and a second cylindrical portion with a second outer diameter corresponding to the larger diameter of an outer bore portion, and a separate, essentially cylindrical contact carrier part fixed in the base body, which has contact pins protruding from an inner end face located on the inside of the thick-walled housing part. A fastener detachably fastens the connection part inserted in the stepped bore in the bore of the housing part.

A sensor mounting tool includes: a rail-shaped sensor holder having a first side wall in which a first connection hole is formed; a band part that has a first projection part, and that is formed to be wound on the outer peripheral surface of a cylinder tube; and a fastening mechanism that is for fastening the band part, and that is arranged at a position shifted away from the sensor holder on the outer peripheral surface of the cylinder tube.

A hydraulic cylinder is provided with a cylinder tube, a piston unit, and a piston rod. The piston unit has a piston body; packing mounted on the piston body; a holding member mounted on the piston body; and a magnet held by a magnet holding part of the holding member. The magnet holding part has a notch that is open on the outer circumferential surface of the holding member.