ROLLER SCREW AND METHOD OF CIRCULATING ROLLERS IN ROLLER SCREW
First Claim
1. A roller screw comprising:
- a screw shaft having a spiral roller-rolling surface on an outer peripheral surface thereof;
a nut having a spiral loaded roller-rolling surface on an inner peripheral surface thereof, the loaded roller-rolling surface being opposed to the roller-rolling surface of the screw shaft;
a circulation member arranged in the nut and formed to have an unloaded return path connecting one end and the other end of the loaded roller-rolling surface, whose turn number is less than one, of the nut; and
a plurality of rollers arranged in a one-turn roller circulation path composed by a loaded roller-rolling path having less than one turn between the roller-rolling surface of the screw shaft and the loaded roller-rolling surface of the nut and an unloaded return path of the circulation member,wherein the circulation member is formed to guide the rollers which have rolled and arrived at one end of the loaded roller-rolling path of less than one turn to the unloaded return path and to return the rollers to the other end of the loaded roller-rolling path of less than one turn, when the screw shaft is relatively rotated to the nut.
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Accused Products
Abstract
There is provided a roller screw in which a twisted amount of an unloaded return path is reduced.
The roller screw has a screw shaft 1 having a spiral roller-rolling surface is on an outer peripheral surface thereof; a nut 2 having a spiral loaded roller-rolling surface 2a on an inner peripheral surface thereof, the spiral loaded roller-rolling surface being opposed to the roller-rolling surface is of the screw shaft 1; a circulation member 7 arranged in the nut 2 and formed to have an unloaded return path 8 connecting one end and the other end of the loaded roller-rolling surface 2a, whose turn number is less than one, of the nut 2; and a plurality of rollers 4 arranged in a one-turn roller circulation path composed by a loaded roller-rolling path 6 and the unloaded return path 8. The circulation member 7 guides the rollers which have moved and arrived at the one end of the loaded roller-rolling path 6 having less than one turn, to the unloaded return path 8, and then returns the rollers to the other end of the loaded roller-rolling path 6 having less than one turn. The number of turns of the loaded roller-rolling path 6 is set to be less than one turn, whereby the rollers 4 which have arrived at one end of the loaded roller-rolling path 6 can be transferred to the other end of the loaded roller-rolling path 6 without changing their attitudes.
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Citations
6 Claims
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1. A roller screw comprising:
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a screw shaft having a spiral roller-rolling surface on an outer peripheral surface thereof; a nut having a spiral loaded roller-rolling surface on an inner peripheral surface thereof, the loaded roller-rolling surface being opposed to the roller-rolling surface of the screw shaft; a circulation member arranged in the nut and formed to have an unloaded return path connecting one end and the other end of the loaded roller-rolling surface, whose turn number is less than one, of the nut; and a plurality of rollers arranged in a one-turn roller circulation path composed by a loaded roller-rolling path having less than one turn between the roller-rolling surface of the screw shaft and the loaded roller-rolling surface of the nut and an unloaded return path of the circulation member, wherein the circulation member is formed to guide the rollers which have rolled and arrived at one end of the loaded roller-rolling path of less than one turn to the unloaded return path and to return the rollers to the other end of the loaded roller-rolling path of less than one turn, when the screw shaft is relatively rotated to the nut. - View Dependent Claims (2, 3, 4, 5)
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6. A method of circulating rollers in a roller screw, guiding the rollers which have moved and arrived at one of ends of a loaded roller-rolling path having less than one turn, into an unloaded return path of the circulation member, wherein the loaded roller-rolling path is formed between a spiral roller-rolling surface on an outer peripheral surface of the screw shaft and a spiral loaded roller-rolling surface on an inner peripheral surface of a nut, and returning the rollers to the other end of the loaded roller-rolling path having less than one turn.
Specification