Roller screw
AssigneeHitachi, Ltd.
InventorsHiroyuki Yamada, Isao Hayase
Life of this patent
Estimating the term…
Abstract
In a roller screw (1) having a screw shaft (2), a plurality of rollers (4) that roll on a flank face (21a) of the screw shaft; and a cage (3) that rotatably houses the plurality of rollers, a plurality of roller groups (40) each having a plurality of rollers arranged at equal intervals while contacting with the same flank face along a spiral groove of the screw shaft for one lead are provided, and the plurality of roller groups are arranged at intervals in the axial direction of the screw shaft. With this configuration, the size of the nut portion in the axial direction of the screw shaft can be prevented from being bloated, and the load distribution in a circumferential direction of the screw shaft can be uniformized.
Claims5
A roller screw comprising:
- a screw shaft;
- a plurality of rollers that roll on a flank face of the screw shaft;
- and
- a cage that rotatably houses the plurality of rollers,
- wherein a plurality of roller groups, each having a plurality of the rollers that roll on said flank face of the screw shaft and that are arranged at equal intervals while contacting said flank face of the screw shaft along a spiral groove of the screw shaft for one lead, are provided,
- wherein the plurality of roller groups are arranged at intervals in the axial direction of the screw shaft,
- wherein diameters of the rollers included in the plurality of roller groups are larger than pitches of the screw shaft,
- wherein the number of rollers in the respective roller groups is equal to each other, and
- wherein when one roller group of the plural roller groups, and another roller group adjacent to the one roller group are viewed from the axial direction of the screw shaft, arrangement positions of the plural rollers in both of the one roller group and the another roller group are different from each other.
Dependencies are inferred from the claim text.