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Screw device capable of detecting preload

A lead screw and lead screw shaft technology, which is applied in the directions of transmissions, transmission parts, belts/chains/gears, etc., can solve the problems of the rigidity of the screw device, the reduction of positioning accuracy, the reduction of the preload of the screw device, etc. Detect the effect of preload and strain amount expansion

Active Publication Date: 2021-09-21
THK CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If these components are worn, the preload of the screw device will decrease, thereby reducing the rigidity and positioning accuracy of the screw device.

Method used

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  • Screw device capable of detecting preload
  • Screw device capable of detecting preload
  • Screw device capable of detecting preload

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0029] figure 1 A perspective view showing the appearance of the screw device 1 according to the first embodiment of the present invention, figure 2 A sectional view along the axis of the spindle arrangement 1 is shown. The screw device 1 of the present embodiment includes a screw shaft 2 , a nut 3 , and balls 4 as rolling elements interposed between an outer surface groove 2 a of the screw shaft 2 and an inner surface groove 3 a of the nut 3 .

[0030] On the outer surface of the screw shaft 2, a spiral outer surface groove 2a in which the balls 4 roll is formed. The cross-sectional shape of the outer surface groove 2a perpendicular to the longitudinal direction is a pointed arch shape formed by combining two arcs with a radius slightly larger than that of the ball 4 (see Figure 4 (b)). The ball 4 is in contact with the outer surface groove 2a at two points.

[0031] Insert the screw shaft 2 into the nut 3 . One end in the axial direction of the nut 3 is provided with ...

no. 2 approach

[0052] Figure 10 An external perspective view showing a bar device 21 according to a second embodiment of the present invention, Figure 11 A sectional view along the axis of the screw device 21 is shown. The screw device 21 of the second embodiment also includes a screw shaft 2 , a nut 3 , and balls 4 as rolling elements interposed between the outer surface groove 2 a of the screw shaft 2 and the inner surface groove 3 a of the nut 3 .

[0053] The screw device 1 of the first embodiment is a screw device 1 with oversized ball preloading. In contrast, the screw device 21 of the second embodiment is a screw device 21 with bias preloading. That is, if Figure 12 As shown in (a) and (b), a part 3a1 of the inner surface groove 3a of the nut 3 is offset in the axial direction of the nut 3 with respect to the other part 3a2 of the inner surface groove 3a of the nut 3 . The circulation circuit using a part 3a1 of the inner surface groove 3a and the circulation circuit using the o...

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PUM

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Abstract

Provided is a screw device in which a preload is imparted with a single nut, wherein the preload can be detected easily. This screw device (1) is provided with: a screw shaft (2) having an outer surface groove (2a) with a helical shape; a nut (3) into which the screw shaft (2) is fitted, the nut having a helical inner-surface groove (3a) and a return path (9), a passage (8) formed between the outer-surface groove (2a) and the inner-surface groove (3a) being joined to the return path (9); a plurality of rolling elements (4) arranged in the passage (8) and the return path (9); and a strain sensor (5) attached to an outer surface of the nut (3). At least one hole (11) is provided between an inner surface (3d) of the nut (3) and an attachment surface (3e) of the nut (3) and / or a vicinity of the attachment surface, the attachment surface being a surface to which the strain sensor (5) is attached.

Description

technical field [0001] The present invention relates to a screw device capable of detecting preload. Background technique [0002] The screw device includes a screw shaft, a nut, and a plurality of rolling elements interposed between the screw shaft and the nut. When the screw shaft is rotated by a motor or the like, the nut moves linearly. A screw assembly is used as a mechanical element that converts motion between rotary motion and linear motion. Since the rolling elements perform rolling motion during the rotation of the screw shaft, it has the feature of reducing frictional resistance. [0003] In order to increase the rigidity of the screw unit and improve the positioning accuracy, a preload is applied to the screw unit. As the preloading method of the screw device, double nut preloading, offset preloading, and oversized ball preloading are known. In the double-nut preload, two nuts are used, and a spacer is interposed between the two nuts so that the axial clearan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F16H25/22
CPCF16H25/24F16H25/22F16H25/2204F16H57/01F16H2057/012
Inventor 久保田祐次铃木浩史富山贵光辻泽优太
Owner THK CO LTD