Ball screw device

Abstract

To provide a ball screw device which is improved in workability, durability and quietness while suppressing a cost.SOLUTION: A ball screw device comprises: a screw shaft 10 having a spiral screw groove 11 at an external peripheral face; a nut 20 that has a spiral screw groove 21 at an internal peripheral face and externally fits to the screw shaft 10; a plurality of balls 30 accommodated in a rolling path 32 which is formed by the first screw groove 11 of the screw shaft 10 and the second screw groove 21 of the nut 20; a circulation dowel 40 arranged at the nut 20, and forming a circulation path which is connected to the rolling path 32, and in which the balls 30 can circulate. The circulation dowel 40 has a guide wall part 44 for delivering the balls 30 between the second screw groove 21 of the nut 20 and itself, and a contact point Pc of the balls 30 at an end part of the guide wall part 44 is located in a position in which a linear line L1 orthogonal to a center O of the screw shaft 10 and a contact line L2 contacting with the balls 30 in the second screw groove 21 of the nut 20 intersect with each other.SELECTED DRAWING: Figure 3

Claims

1. A screw shaft having a helical screw groove on its outer surface, A nut having a helical screw groove on its inner surface and fitted onto the screw shaft, A plurality of balls housed in the rolling path formed by the screw shaft and the screw groove of the nut, A circulating member provided on the nut, which connects the rolling paths and forms a circulation path through which the balls can circulate, Equipped with, The circulating member has a guide wall portion that transfers the ball between itself and the screw groove of the nut, The contact point of the ball at the end of the guide wall is positioned at the intersection of a straight line perpendicular to the center of the screw shaft and the contact line in the screw groove of the nut where the ball makes contact. The end of the guide wall portion has an edge that intersects diagonally with respect to the direction of movement of the ball, and the contact point is located on the edge. Ball screw device.

2. The circulating member is fitted into a mounting hole formed radially in relation to the nut. The ball screw device according to claim 1.

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