A linkage system for transmitting torque includes a central element, an input arm and an output arm. The central element has four sides and a top and bottom. The input arm and an output arm each have a head portion for connecting with the central element and a body portion. The head portion of each of the input and output arms defines a bearing surface having a first radius. The input and output arms engage the central element such that the bearing surfaces of the heads are offset by 90 degrees.

A universal joint including a joint cross having a bearing journal supported in a trunnion bearing having a bearing bushing and a seal assembly including a one-piece seal body sealing the journal cross against the bearing bushing, the seal body having a first lip configured to form a dynamic seal on the bearing bushing or on a U-shaped sleeve connected to the bearing bushing, a second lip configured to form a dynamic seal on the bearing bushing or on the sleeve, a first arm of the sleeve being press-fit in a cylindrical receiving surface of the bearing bushing, or the sleeve having a section that is rounded or doubly corrugated in radial section, or wherein between the seal body and rolling elements of the trunnion bearing a separate ring part is disposed and pressed towards the rolling elements by at least one elastic element projecting from the seal body.

A robot apparatus includes: a base plate; a rotation-driving motor provided on the base plate; a transmission mechanism that is provided on a bottom surface side of the base plate and to which a rotational force of the rotation-driving motor is transmitted; and a rotation-driving mechanism that is provided on the bottom surface side of the base plate and to which the rotational force of the rotation-driving motor is input via the transmission mechanism. A workpiece is rotated by the rotation-driving mechanism at an end of the rotation-driving mechanism opposite to the base plate.

A sealing assembly for a cup bearing of a universal joint includes a seal sub-assembly configured to be positioned in a space between a cup of the cup bearing and a trunnion of the universal joint. The seal sub-assembly includes an elastic sealing member configured to contact an outer surface of the trunnion, and a seal insert attached to the elastic sealing member and configured to contact an inner surface of the cup. The seal insert includes an extension portion configured to contact and extend away from a rim surface of the cup. The sealing assembly further includes an external shield including an inner portion and an outer portion. The inner portion is configured to contact the outer surface of the trunnion, and the outer portion is attached to the extension portion of the seal insert.

Universal joint bushes for universal joints are disclosed, as well as methods of making or treating the universal joint bushes. The universal joint bush may include an outer ring, which has a peripheral layer (R) formed by at least one measure for diffusing an element into regions of the universal joint bush near the surface. The peripheral layer (R) of the outer ring may include nitrogen. A method for producing a universal joint bush having a nitrogen-containing peripheral layer (R) may include preparing a universal joint bush made from a case-hardened steel and diffusing, via a thermochemical treatment, nitrogen into regions of the universal joint bush that are close to the surface in order to form the nitrogen-containing peripheral layer (R). The thermochemical treatment may be carried out in a temperature range of at least 800 C.

After a cup bearing (13a) is incorporated into a circular hole (11c) of a coupling portion (10c) forming a yoke, a notch (25) having a V-shaped cross section is formed in a portion near the periphery of the circular hole (11c) on an outer side surface of the coupling arm portion (10c). Thereafter, a thin-walled portion (27) having a substantially trapezoidal cross section formed in a radially inner portion of the notch (25) in an opening edge portion of the circular hole (11c) is plastically deformed inward in a radial direction to form a staking portion (14a). Therefore, it is possible to achieve a method of assembling a joint cross type universal joint and a joint cross type universal joint which can form the staking portion for preventing the cup bearing from falling off without complicating the staking work.

A pin is made of a synthetic resin having an appropriate thermal expansion rate and a low friction coefficient. At a state where respective members configuring a cross shaft universal joint are assembled, a tip portion of the pin is heated and softened, and one yoke is pivotally displaced relative to other yoke. Thereby, it is possible to set a fitting margin of the pin to a bottom inner surface of a bearing cup to an appropriate size and to adjust a shape of an end surface of the pin.

A seal for sealing between a trunnion and bearing cup of a joint member includes a main annular body. A plurality of annular lips extend radially inwardly from the main body. The lips are configured for engaging an outer bearing surface of the trunnion. A first one and a second one of the lips slope in a first direction with respect to the outer bearing surface of the trunnion and a third one of the lips slope in a second direction with respect to the outer bearing surface of the trunnion.

A universal joint having a retainer ring that secures a bearing cup to a cross shaft. A bearing cup retainer may secure the bearing cup to the retainer ring. A cross shaft retainer may secure the retainer ring to the cross shaft. A seal may extend from the body of the retainer ring to the cross shaft.

A universal joint bearing with at least a first and a second elastomeric ring. The universal joint bearing is free from spiral springs, which exert a force on a portion of one of the elastomeric rings. The portion is provided for abutting against a trunnion of a crosspiece of a universal joint in a condition in which the universal joint bearing is part of the universal joint.