Screw circulating ball screw

Abstract

This invention relates to a screw-type circulating ball screw, comprising: a nut having an internal threaded groove; a screw rotatably inserted through the nut, having a return channel extending axially along the screw, an external threaded groove forming a helical channel with the internal threaded groove, and two receiving grooves extending radially from the external threaded groove along the screw to communicate with the return channel; two return elements disposed in the receiving grooves of the screw, each having a deflection channel connecting the return channel and the helical channel; and a plurality of balls rotatably disposed in the return channel, the helical channel, and the deflection channel; wherein the pitch circle diameter of the screw is PCD, the groove depth of the receiving groove of the screw is DP, the diameter of the ball is BD, and the safety value is SF, and satisfies the following conditions: BD < DP < (PCD - BD - SF), and 0.28 * BD < SF < 0.98 * BD.

Claims

1. A screw-type circulating ball screw, comprising: a nut having an internal threaded groove; a screw rotatably inserted through the nut, having a return channel extending axially along the screw, an external threaded groove forming a helical channel with the internal threaded groove, and two receiving grooves extending radially from the external threaded groove along the screw to communicate with the return channel; two return elements disposed in the receiving grooves of the screw, each having a deflection channel connecting the return channel and the helical channel; and a plurality of balls rotatably disposed within the return channel, the helical channel, and the deflection channel; wherein, The screw has a pitch circle diameter of PCD, a groove depth of DP, a ball diameter of BD, and a safety value of SF, and satisfies the following conditions: BD < DP < (PCD - BD - SF) and 0.28 * BD < SF < 0.98 * BD.

2. The screw-type ball screw as described in claim 1, wherein, The diameter BD of the ball and the safety value SF satisfy the following conditions: 0.35*BD≦SF≦0.82*BD.

3. The screw-type ball screw as described in claim 1, wherein, The path of the steering channel includes a compound curve comprising a first curve segment connecting the external threaded groove, a second curve segment connecting the first curve segment, and a third curve segment connecting the second curve segment and the return channel. The radius of curvature of the first curve segment is R1, the radius of curvature of the second curve segment is R2, and the radius of curvature of the third curve segment is R3, and satisfies the following conditions: 0.5*BD < R1 < 0.5* (PCD-BD-SF), 0.5*BD < R2 < 0.5* (PCD-BD-SF), and 0.5*BD < R3 < 0.5* (PCD-BD-SF).

4. The screw-type ball screw as described in claim 1, wherein, The screw has two receiving grooves, each including a first groove and a second groove. The first groove has a first groove bottom surface and a first groove wall surface. The first groove wall surface is connected in the radial direction of the screw and not connected in the axial direction of the screw. The second groove is recessed from the first groove bottom surface along the radial direction of the screw, so that the first groove bottom surface is divided into a first plane and a second plane. The two return elements also each have a positioning part disposed in the second groove, a bearing part abutting against the first plane, and a fixing part fixed to the second plane.

5. The screw-type ball screw as described in claim 4, wherein, The second groove has a second groove bottom surface and a second groove wall surface that surrounds the screw radially and connects to the return channel.

6. The screw-type ball screw as described in claim 4, wherein, The fixing part of each of the two return elements is fixed to the second plane of the screw by a fixing member.

7. The screw-type ball screw as described in claim 4, wherein, Secondly, each of the recirculation elements also has a nail portion, which has a portion of its outer surface extending beyond the outer ring surface of one of the screws.

Images