JPS61133832A - Screw tester - Google Patents

Abstract

PURPOSE:To measure uneven torque accurately, by mounting a cantilever on a female thread combined with a male thread of a combination thread for precision thread to engage the tip thereof with a load cell. CONSTITUTION:A cantilever 7 is fastened to a female thread 6 of a combination thread and a load cell 9 is engaged with the tip thereof. A motor 3 is started to transmit the rotation thereof to a male thread 5 through a coupling 2, a bearing 4 and the like. According to the rotation of the male thread 5, the female thread 6 moves in the axial direction of the male thread 5 and the cantilever 7 tends to turn according to the torque generated between both the threads. The resulting force is measure with the load cell 9 to detect the uneven torque of the combination thread. The axial movement of a load cell 9 enables precise detection of uneven torque. Moreover, joint arrangement of laser length measuring apparatus 12-15, a collimator 16 and the like permits simultaneous measurement of pitch errors.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a screw testing machine, and in particular is used as a precision feed screw in precision machines such as precision measuring machines and semiconductor printing equipment.
This invention relates to a screw testing machine that has a simple structure and can easily and accurately measure the torque unevenness of only a combination of male and female threads.

[Background of the Invention] Precision machines such as precision measuring machines and semiconductor printing equipment are required to perform more accurate measurement and alignment.

Therefore, the precision feed screws used in these machines need to be manufactured precisely, and the torque unevenness needs to be accurately known.

However, conventional measuring machines for measuring torque unevenness of precision feed screws are of the direct-coupled type, and there are parts between the measured object and the torque detection section that support the measured object, such as bearings and lubricants. Because of this, it was only possible to make measurements that included the torque unevenness of the support member.

Therefore, in order to measure the torque unevenness of the precision feed screw with higher accuracy, there is a need for an apparatus that can eliminate the torque unevenness of the support member of the object to be measured and measure only the torque unevenness of the precision feed screw.

[Purpose of the Invention] The present invention has been made in view of the problems of the prior art described above, and is capable of reducing only the torque unevenness of a combination screw of a male screw and a female screw, without being affected by the support member of the object to be measured. The purpose of the present invention is to provide a screw testing machine that has a simple structure and can perform simple and precise measurements.

[Explanation of Examples] Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic perspective view of a screw testing machine according to an embodiment of the present invention. In the figure, 1 is a rotary encoder for detecting the position of a female thread that measures the rotation angle of the shaft, 2 is a coupling, 3 is a drive motor, and 4 is an air bearing for removing thrust play. 5 is a male screw, 6 is a female screw, and these constitute one combination screw. 7 is a cantilever fixed to the female screw 6. 8 is a bearing that supports the male screw 5; 9 is a load cell (load measurement m>r: it engages with the tip of the cantilever 7, and detects the load that causes the cantilever 7 to rotate; 10 supports the load cell 9); When the cantilever 7 moves in the axial direction of the male screw 5 due to the rotation of the male screw 5, the load cell 9 is moved along with the cantilever 7 without applying a load. 1
2 is a laser emission source, 13 is an interferometer, 14 is a reflector, and 15 is a receiver (
Detector) These constitute a complete set of laser length measuring devices.

16 is a collimator, and 17 is a mirror for the collimator.
These are fixed to the cantilever 7 and measure the inclination angle of the cantilever 7.

Next, a method for measuring torque unevenness of a combination screw will be explained based on FIG.

First, by starting the motor 3, the rotation of the motor 3 is transmitted to the male screw 5 via the coupling 2, the bearing 4, etc. Then, the female screw 6 moves in the axial direction of the male screw 5 in accordance with the rotation of the male screw 5.

At this time, since the cantilever 7 is fixed to the female screw 6, the cantilever 7 tends to rotate in response to the torque generated between the male screw 5 and the female screw 6. Then, the force of the tip of the cantilever 7 to rotate is applied to the load cell 9, which detects the torque unevenness of the combination screw.

According to such a structure, since there is no support member for the object to be measured such as the bearings 4 and 8 interposed between the male screw 5, the female screw 6 and the load cell 9, the torque of only the combination screw excluding the influence of these It becomes possible to measure unevenness.

Here, the female screw 6 and the cantilever 7 move along the axial direction of the male screw 5, but the load cell 9 also moves along the L A B 10
．． Since the f5 and LA8 guy guides 11 can freely move in the axial direction, it is possible to accurately detect torque unevenness applied to the combination screw.

Therefore, with such a testing machine, it is possible to measure the starting torque at any position of the combination screw and the torque fluctuation during constant speed rotation in both left and right rotations.

In addition, in the present invention, a laser m-length device 1 as shown in FIG.
2 to 15, a collimator 16, etc., it is also possible to measure pitch errors at the same time.

[Application Example of the Invention] In the above-mentioned embodiment, the torque unevenness was measured using a combination of male and female threads, but in the present invention, a standard male or female thread with grooves formed accurately in advance was measured. By attaching it to either the male thread 5 or the female thread 6 shown in FIG.

[Effects of the Invention] As explained above, according to the present invention, only the torque of the combination screw is transmitted to the load cell via the cantilever, thereby eliminating the influence of members such as bearings that support the object to be measured. , it is possible to measure torque unevenness of only combination screws.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of an embodiment of the present invention. 1... Rotary encoder, 2... Coupling, 3... Motor, 4.8... Bearing, 5... Male thread, 6... Female thread, 7... Cantilever, 9... Load cell, 10...LAB, 11...t, AB guide, 12...laser emission source, 13...interferometer, 14...reflector, 15...receiver, 16... Collimator, 17...mirror.

Claims (1)

[Claims] 1. A screw testing machine for measuring torque unevenness of only a combination screw consisting of a male screw and a female screw for precision feeding, in which a cantilever is attached to the female screw combined with the male screw, and the tip of the cantilever is A screw testing machine characterized by being engaged with a load cell. 2. The screw testing machine according to claim 1, wherein the load cell is movably supported along with the cantilever by a linear air bearing.