METHOD FOR DETECTING PRELOAD RESIDUAL RATE

• US 20150377719A1
• Filed: 08/07/2014
• Published: 12/31/2015
• Est. Priority Date: 06/25/2014
• Status: Active Grant

• Current Assignee: HIWIN Technologies Corp.
• Original Assignee: HIWIN Technologies Corp.
• Inventors: TSAI, MENG-SHIUN, HSIEH, WEN-HSIN, YANG, AN-SHIK, YUAN, WEI-HSIANG, HUANG, HONG-WEI, LIU, CHUNG-CHING, HWANG, YIH-CHYUN
• Granted Patent: US 9,593,987 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F16H 25/2204 with balls
• CPC Class Codes: F16H 25/2209 with arrangements for taking up backlash
• CPC Class Codes: G01K 13/08 in rotary movement
• CPC Class Codes: G01K 3/10 in respect of time, e.g. reacting only to a quick change of temperature
• CPC Class Codes: G01L 1/00 Measuring force or stress, in general measuring force due to impact G01L5/00

Abstract

A method for detecting a preload residual rate involves: a. installing a temperature sensor on one of two preloaded elements; b. making the two preloaded elements to move with respect to each other, and recording a time-related temperature variation sensed by the temperature sensor, so as to obtain an initial temperature-rising curve; c. making the two preloaded elements to move with respect to each other, and recording a time-related temperature variation sensed by the temperature sensor, so as to obtain a detected temperature-rising curve; and d. comparing the initial and detected temperature-rising curves, so as to obtain the preload residual rate between the two preloaded elements of the step c to the step b. The method detects a preload residual rate applied to an object when the object is operating while being advantageous in terms of cost, service life, response and accuracy.

Claims

1. A method for detecting a preload residual rate, the method comprising steps of:

a. installing a temperature sensor on one of two preloaded elements that are configured to move with respect to each other;

b. making the two preloaded elements to move with respect to each other, and simultaneously recording a time-related temperature variation sensed by the temperature sensor, so as to obtain an initial temperature-rising curve;

c. making the two preloaded elements to move with respect to each other, and simultaneously recording a time-related temperature variation sensed by the temperature sensor, so as to obtain a detected temperature-rising curve; and

d. comparing the initial temperature-rising curve with the detected temperature-rising curve, so as to obtain the preload residual rate between the two preloaded elements of the step c to the step b.

2. The method of claim 1, wherein in the steps b and c the two preloaded elements move with respect to each other at an identical velocity.

3. The method of claim 1, wherein the two preloaded elements are a screw and a nut of a ball screw device, and the steps a and b are performed at a manufacturer'"'"'s side, while the steps c and d are performed at a user'"'"'s side.

4. The method of claim 3, wherein in the steps b and c the nut moves along the screw linearly at an identical velocity.

5. The method of claim 2, wherein the step b further comprises deriving an initial temperature-rising rate from the initial temperature-rising curve, and the step c further comprises deriving a detected temperature-rising rate from the detected temperature-rising curve, in which the preload residual rates of the step d is a ratio between the detected temperature-rising rate and the initial temperature-rising rate.

6. The method of claim 5, wherein each of the initial temperature-rising curve and the detected temperature-rising curve has an almost straight linear segment, in which the initial temperature-rising rate and the detected temperature-rising rate are slopes of the linear segments of the initial temperature-rising curve and the detected temperature-rising curve, respectively.

7. The method of claim 4, wherein the step b further comprises deriving an initial temperature-rising rate from the initial temperature-rising curve, and the step c further comprises deriving a detected temperature-rising rate from the detected temperature-rising curve, in which the preload residual rates of the step d is a ratio between the detected temperature-rising rate and the initial temperature-rising rate.

8. The method of claim 7, wherein each of the initial temperature-rising curve and the detected temperature-rising curve has an almost straight linear segment, in which the initial temperature-rising rate and the detected temperature-rising rate are slopes of the linear segments of the initial temperature-rising curve and the detected temperature-rising curve, respectively.

9. The method of claim 3, wherein the nut has an outer periphery, and a receiving hole depressed from the outer periphery toward the screw for allowing the temperature sensor to be installed therein.

10. The method of claim 3, wherein the nut has an end surface, and a receiving hole depressed from the end surface near the screw for allowing the temperature sensor to be installed therein.

11. The method of claim 1, wherein the element on which the temperature sensor is installed has receiving hole for allowing the temperature sensor to be installed therein.

12. The method of claim 1, wherein the temperature sensor is a thermocouple.