Linear actuator

In a linear actuator including a threaded shaft member, a bearing unit mounting member having a portion disposed in substantial concentric relation to the shaft member, a bearing unit interposed between said shaft member and said mounting member for moving one of said members linearly relative to the other member, and means for rotating the shaft member, the improvement wherein said bearing unit comprises:

• an outer race structure received about said shaft member,
• and a plurality of discrete rollers received between said shaft member and said outer race structure in rolling relation about said shaft member and in rolling relation within said outer race structure,
• said rollers each comprising elongate roller elements circumferentially spaced about and extending axially of the shaft member and each defining:
• a bearing surface about either end of same that is oblique relative to the longitudinal axis of the respective rollers,
• and a plurality of right flanges intermediate said bearing surfaces of the respective rollers and in rolling threaded engagement with the shaft member threading,
• said outer race structure defining spaced annular raceways respectively radially aligned with the respective roller bearing surfaces on which the respective roller bearing surfaces ride in rolling engagement therewith, with said raceways being in substantial concentric relation about the shaft member,
• said roller flanges being free of engagement with said outer race structure and the mounting member and said roller elements being in free rolling nonjournalled relation to said outer race structure,
• and means for securing the bearing unit to the mounting member for linearly moving said one member on rotation of said shaft member.

In a linear actuator including a threaded shaft member, a bearing unit mounting member having a portion disposed in substantial concentric relation to the shaft member, a bearing unit interposed between said shaft member and said mounting member for moving one of said members linearly relative to the other member, and means for rotating the shaft member, the improvement wherein said bearing unit comprises:

• an outer race structure received about said shaft member,
• and a plurality of rollers received between said shaft member and said outer race structure in rolling relation about said shaft member and in rolling relation within said outer race structure,
• said rollers each defining:
• a bearing surface at either end of same that is oblique relative to the longitudinal axis of the respective rollers,
• and a plurality of right flanges intermediate said bearing surfaces of the respective rollers and in rolling threaded engagement with the shaft member threading,
• said outer race structure defining spaced annular raceways inwardly disposed and oblique relative to the length of said shaft member and respectively radially aligned with the respective roller bearing surfaces on which the respective roller bearing surfaces ride,
• said roller flanges being free of engagement with said outer race structure and the mounting member,
• and means for securing the bearing unit to the mounting member for linearly moving said one member on rotation of said shaft member,
• said outer race structure comprising a pair of ring members,
• with one of said ring members forming one of said raceways and the other of said ring members forming the other raceway,
• said securing means comprising:
• a pair of annular members keyed to the mounting member and disposed in spaced apart relation on either side of said ring members about the shaft member adjacent opposed ends of said ring members,
• and antifriction means interposed between the respective ring member ends and the annular member adjacent same.

In a linear actuator including a threaded shaft member, a bearing unit mounting member having a portion disposed in substantial concentric relation to the shaft member, a bearing unit interposed between said shaft member and said mounting member for moving one of said members linearly relative to the other member, and means for rotating the shaft member, the improvement wherein said bearing unit comprises:

• an outer race structure received about said shaft member,
• and a plurality of rollers received between said shaft member and said outer race structure in rolling relation thereabout,
• said rollers each defining:
• a bearing surface at either end of same that is oblique relative to the longitudinal axis of the respective rollers,
• and a plurality of right flanges intermediate said bearing surfaces of the respective rollers and in rolling threaded engagement with the shaft member threading,
• said outer race structure defining spaced annular raceways respectively radially aligned with the respective roller bearing surfaces on which the respective roller bearing surfaces ride,
• said roller flanges being free of engagement with said outer race structure and the mounting member,
• and means for securing the bearing unit to the mounting member for linearly moving said one member on rotation of said shaft member,
• said raceway surfaces and said roller bearing surfaces define spherically contoured complementing surfaces struck on an arc having its center on the longitudinal axis of the shaft.

In a linear actuator including a threaded shaft, a member to be moved linearly by the shaft, a bearing unit operatively connected to said member and shaft for translating rotational movement of said shaft to linear movement of said member, and means for rotating the shaft, the improvement wherein said bearing unit comprises:

• an outer race structure received about said shaft,
• and a plurality of rollers received between said shaft and said outer race structure in rolling relation thereabout,
• said rollers each defining:
• a bearing surface at either end of same that is oblique relative to the longitudinal axis of the respective rollers,
• and a plurality of right flanges intermediate said bearing surfaces of the respective rollers and in rolling threaded engagement with the shaft,
• said outer race structure defining spaced annular raceways respectively radially aligned with the respective roller bearing surfaces on which the respective roller bearing surfaces ride,
• said roller flanges being free of engagement with said outer race and the tubular member,
• said improvement further including:
• means for resiliently coupling the member to said race structure for movement therewith linearly of the shaft on rotation of the shaft,
• a roller support threaded on said shaft and having said rollers disposed therein in free rolling relation relative thereto,
• and a stop fixed with respect to the member and disposed adjacent but spaced from one end of said roller support,
• said coupling means including resilient means acting on said race structure to resiliently bias said bearing unit to space said roller support one end from said stop,
• whereby on rotation of said shaft, said rollers roll thereabout to move the member longitudinally of the shaft through said coupling means, and when shock loads acting longitudinally of the shaft in the direction to move said roller support toward said stop are occasioned, said resilient means yields to bring said end of said roller support to bear against the stop to resist the shock load.

A motion translating bearing unit for application between a threaded shaft member and a member for mounting the bearing unit to move one of the members linearly of the other by the translation of rotary motion to linear motion through the bearing unit, sad bearing unit comprising:

• a plurality of rollers having right flanges along their shanks spaced for rolling engagement with the shaft threading,
• said rollers at their ends defining bearing surfaces that are oblique relative to their longitudinal axes,
• an outer race structure defining spaced apart raceway surfaces about which said roller bearing surfaces respectively ride,
• and a roller support about which said rollers are received in free rolling nonjournaled relation thereto,
• said support being formed to be received over the shaft,
• said rollers having projecting end portions and said support being formed for cooperation with said roller end portions to support the rollers against substantial radial displacement relative to said raceways when the bearing unit is free of the shaft.