A dry running mechanical ball joint seal includes a spherical element penetrated by a central passage and suspended between support rings that are pressed by springs against the spherical element and form a sliding dry seal therewith. A lip seal is located between the support rings and includes wipers pressed radially inward by a lip seal spring to form an additional seal with the spherical element. In embodiments directed to piping systems, a fluid is able to flow through the central passage. Other embodiments include a sliding rod directed through the central passage and sealed to the spherical element by a rod support within the central passage and also by at least one rod lip seal having a wiper pressed by a spring against the rod. The rod support can include a compressible packing material and/or a linear ball bearing sealed to the spherical element within the central passage.

Provided is a linear-motion bearing, including: an outer cylinder member made of a synthetic resin, the outer cylinder member having a plurality of endless steel ball circulation paths each including an outer-peripheral-side steel ball circulation path and an inner-peripheral-side steel ball circulation path, and having sheet-like spaces in regions that are opposed to the endless steel ball circulation paths, respectively; a plurality of steel balls accommodated and arrayed in the endless steel ball circulation paths; and a synthetic resin plate, which has an arc cross section, and is fitted to each of the sheet-like spaces, the synthetic resin plate including a metal piece at a position at which the synthetic resin plate is held in contact with a steel ball row in the inner-peripheral-side steel ball circulation path, the metal piece having an elongated shape in a direction along the steel ball row in the inner-peripheral-side steel ball circulation path, in which the elongated metal piece is curved so as to protrude toward an inner peripheral side of the outer cylinder member in the direction along the steel ball row in the inner-peripheral-side steel ball circulation path.

A dry running mechanical ball joint seal includes a spherical element penetrated by a central passage and suspended between support rings that are pressed by springs against the spherical element and form a sliding dry seal therewith. A lip seal is located between the support rings and includes wipers pressed radially inward by a lip seal spring to form an additional seal with the spherical element. In embodiments directed to piping systems, a fluid is able to flow through the central passage. Other embodiments include a sliding rod directed through the central passage and sealed to the spherical element by a rod support within the central passage and also by at least one rod lip seal having a wiper pressed by a spring against the rod. The rod support can include a compressible packing material and/or a linear ball bearing sealed to the spherical element within the central passage.

A linear-motion bearing is disclosed including: an outer cylinder member having a plurality of endless steel ball circulation paths each including an outer-peripheral-side steel ball circulation path and an inner-peripheral-side steel ball circulation path, and having planar spaces in regions that are opposed to the endless steel ball circulation paths, respectively; a plurality of steel balls accommodated and arrayed in the endless steel ball circulation paths: and a synthetic resin plate including a metal piece at which the synthetic resin plate is held in contact with a steel ball row, the metal piece having an elongated shape in a direction along the steel ball row in the inner-peripheral-side steel ball circulation path, in which the elongated metal piece is curved so as to protrude toward an inner peripheral side of the outer cylinder member in the direction along the steel ball row in the inner-peripheral-side steel ball circulation path.

A linear motion bearing assembly comprising a rolling element retainer structure and an outer housing sleeve enclosing substantially all of an exposed exterior surface of said rolling element retainer structure. A bearing block effective to enclose substantially all of an exposed exterior surface of the outer housing sleeve, the bearing block including a first bearing block segment effective to enclose a first part of the outer housing sleeve; and a second bearing block segment effective to enclose a second part of the outer housing sleeve, wherein the first bearing block segment and the second bearing block segment include first elements and second elements effective to interlock with each other when the bearing block encloses the outer housing sleeve.