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US 6,454,042 B1Granted
Ball screw and electrically powered steering device having the ball screw
AssigneeNtn Corporation
InventorsIsamu Yoshida, Yoshinori Ikeda
Life of this patent
Estimating the term…
Abstract
A ball screw (20) includes a bridge member (24) fitted to a rotary nut (22) and provided with a plurality of connecting grooves (28). Each connecting groove (28) connects neighboring convolutions of an inner spiral groove (26) of the rotary nut (22). The ball screw (20) is used as a mechanism for transmitting rotation of a rotor (10) of a motor (8) to a steering shaft (2)in an electrically powered steering device.
Claims9
A ball screw which comprises:
- a screw shaft;
- a rotary nut having at an inner periphery thereof an inner spiral groove facing the screw shaft;
- a plurality of balls disposed in a rolling guideway formed between the screw shaft and the inner spiral groove for transmitting a force between the rotary nut and the screw shaft;
- and
- a bridge member fitted to the rotary nut and having a plurality of connecting grooves, each connecting neighboring convolutions of the inner spiral groove, wherein said bridge member is provided with an arm being engaged with the inner spiral groove of the rotary nut so as to position the bridge member in an axial direction with respect to the rotary nut;
- and wherein said arm is provided with a slit extending from a tip end toward a base portion of the arm.
3 more elements
A ball screw which comprises:
- a screw shaft;
- a rotary nut having at an inner periphery thereof an inner spiral groove facing the screw shaft;
- a plurality of balls disposed in a rolling guideway formed between the screw shaft and the inner spiral groove for transmitting a force between the rotary nut and the screw shaft;
- and
- a bridge member fitted to the rotary nut and having a plurality of connecting grooves, each connecting neighboring convolutions of the inner spiral groove, wherein said bridge member is provided with a pair of guide walls protruding radially outwardly from the rotary nut from opposite edges of the bridge member confronting to each other in a circumferential direction of the rotary nut and the guide walls are in elastic contact with a pair of inner surfaces, facing each other, of a bridge member fitting opening formed in the rotary nut.
2 more elements
Dependencies are inferred from the claim text.