The present invention relates to provision of an extreme pressure agent-containing grease composition using, as a thickener, a urea-based thickener, the grease composition being excellent in both torque transmitting efficiency and leakage prevention performance and also excellent in wear resistance and load resistance. The grease composition contains a base oil (A), a urea-based thickener (B), and an extreme pressure agent (C), wherein particles containing the urea-based thickener (B) in the grease composition satisfies the following requirement (I): Requirement (I): an arithmetic average particle diameter of the particles on an area basis as measured by the laser diffraction/scattering method is 2.0 μm or less, and the extreme pressure agent (C) is at least one selected from an organic metal-based extreme pressure agent, a sulfur-based extreme pressure agent, a phosphorus-based extreme pressure agent, and a sulfur-phosphorus-based extreme pressure agent.

When a strain wave gearing is used in an application for an operation of repeating startup/stopping, an outer-side lubrication portion and an inner-side lubrication portion, which are lubricated using different types of grease, remain in a communicating state without being divided using a seal member or the like. The outer-side lubrication portion is supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Similarly, the inner-side lubrication portion is also supplied with a much smaller amount of grease than the amount that would be required if used in an application such as a steady operation. Essentially, the outer-side lubrication portion and the inner-side lubrication portion can be lubricated appropriately using different types of grease, without the grease becoming mixed.

A lubrication system comprises a lubricant reservoir, a lubricant supply passage fluidly connecting the lubricant reservoir and a space requiring lubrication, and a lubricant supply pump. The supply pump includes a piston having a first piston head slidably received in a chamber in fluid communication with the lubricant reservoir and a second piston head slidably received in a pumping chamber. The pumping chamber is divided into a first and second cavities by the second piston head. The first cavity is between the first piston head and second piston head. The first and second cavities are placeable in fluid communication with pressure sources externally of the pumping chamber to provide a pressure differential between the first cavity and the second cavity, whereby the piston may move as a result of the pressure differential to cause the first piston head to dispense lubricant from the lubricant reservoir to the space.

A gear is provided that has excellent continuous moldability for practical use, and both high slidability and high durability. The provided gear is a molded resin constructed of a resin composition comprising a thermoplastic resin (A) and cellulose nanofibers (B) with an average fiber diameter of 1000 nm or smaller, and having a number average molecular weight of the thermoplastic resin (A) in the range of 10,000 to 150,000, wherein a sliding surface of the gear with another gear teeth has an arithmetic mean surface roughness Sa of 3.0 μm or lower.

A robot includes: a first arm having a first body, a first housing fixed to the first body, and a first gear transmitting power to a rotary member supported by the first housing so as to be rotatable; a second arm supporting the first arm and having a second body, a second shaft having a second gear meshing with the first gear, and a second bearing supporting the second shaft so that the second shaft is rotatable relative to the second body; and a channel in the arms. An inlet of the channel is formed in an outer surface of the first body, an outlet of the channel opening into a space in which an outer peripheral surface of the second shaft and the second bearing are arranged inside the second arm, the channel extending from the inlet to the outlet through inside of the first body.

A strain wave gear system (10) includes first and second sets of ball bearings (80, 82) located intermediate a flange (84) and a retainer plate (88) rotatable with an output (54) and a radially oriented flat disc (74) of the input including strain relief (76). Strain relief (76) is a helical slot in a coupling (70) located radially within the wave generator (94) and the ring gear (22). The ring gear (22) is sealed by a sealing system including sealant (42) forced by a protrusion (34) of the cap (24) entering into a cavity (36) through a channel (40) into a relief volume (38) of the housing (12). The bearing (48) rotatably mounting the housing (12) to the output (54) is lubricated by a lubricating system including plungers (110) threadably received in axial bores (102) intersecting with radial bores (104) in communication with radial holes (47) of the bearing (48).

According to one embodiment, a grease filling method for a ball screw device includes the steps of covering an outer periphery of a screw shaft protruding from one end portion of a nut with a covering member, supplying grease to a portion between a nut inner peripheral surface on one end portion side of the nut and the screw shaft, inserting the protruding screw shaft into a nut inner side while being covered with the covering member by relatively rotating the screw shaft and the nut, bringing a tip of the covering member in an insertion direction closer to an end portion of an infinite circulation path on the one end portion side of the nut, and sending the grease supplied to the nut inner side to a region of the infinite circulation path, pulling out the covering member together with the screw shaft from the one end portion of the nut by relatively rotating the screw shaft and the nut in an opposite direction, and taking out the covering member from the screw shaft.

The present invention relates to provision of an extreme pressure agent-containing grease composition using, as a thickener, a urea-based thickener, the grease composition being excellent in both torque transmitting efficiency and leakage prevention performance and also excellent in wear resistance and load resistance. The grease composition contains a base oil (A), a urea-based thickener (B), and an extreme pressure agent (C), wherein particles containing the urea-based thickener (B) in the grease composition satisfies the following requirement (I): Requirement (I): an arithmetic average particle diameter of the particles on an area basis as measured by the laser diffraction/scattering method is 2.0 μm or less, and the extreme pressure agent (C) is at least one selected from an organic metal-based extreme pressure agent, a sulfur-based extreme pressure agent, a phosphorus-based extreme pressure agent, and a sulfur-phosphorus-based extreme pressure agent.

A radial-type anti-backlash nut for use upon linear actuator leadscrews uses a separate housing resting upon the actuator’s main nut. The anti-backlash action is a multi-finger collet and spring setup located inside the housing. The collet tapers radially inward toward tips of the fingers at a specified taper angle. The whole interior length of an internal thread of the collet engages an external thread of the leadscrew. The housing is a pre-load nut with an internal tapered surface that mates with the collet fingers with substantially the same taper angle. The pre-load nut, when screwed onto external threads of the adjustment nut, both compresses a load spring and applies radially inward adjustable load force to the collet fingers against the leadscrew. Three tolerances adjust load: the taper angle of the main nut’s collet fingers, the spring load’s compression, and the collet finger mismatch with respect to the lead screw.

A drive device includes a motor, an output part outputting torque to the outside, a gear part transmitting torque of the motor to the output part, and a housing having an internal space. The gear part includes at least one gear shaft extending in an axial direction, to which at least one gear is fixed, and a gear case accommodating the gear. The gear case includes a wall part facing an outer circumferential surface of the accommodated gear in a radial direction and extending in a circumferential direction and an opening adjacent to the wall part in the circumferential direction and penetrating in the radial direction. The opening faces the housing in the radial direction, and in a rotation direction of the gear, the wall part includes a front end disposed on a front side of the opening and adjacent to the opening. The front end contacts the housing.