The Impact of Processing Conditions on the Anti-loosening Properties of the Clasp Locking High Precision Locknut

• Main Authors: Huang-Wei Li, 李晃瑋
• Other Authors: Chih-Ming Chen
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/89631710174151116384

碩士 === 國立勤益科技大學 === 機械工程系 === 99 === This study focused on the clasp locking high precision locknut applied in ball screw and high speed precision spindle. Through static torque - axial force tests, as well as dynamic impact tests, this study discussed the relationships between thread flank friction coefficients, clasping torque, loosening torque and axial force of the high precision locknut under different processing conditions and experimental testing factors. This study applied the Taguchi method for analysis to identify major factors of anti-loosening properties in static and dynamic states of the clasp locking high precision locknut in order to determine the impact of different processing conditions and experimental testing factors to obtain the best processing parameters to achieve the anti-loosening effects. Regression analysis was conducted to establish the regression equations for the control factors of the clasp locking high precision locknut in static and dynamic tests and the target properties. The prediction of the properties of the clasp locking high precision locknut in the static and dynamic states based on the experiential equation can provide a reference to high precision nut manufacturers in the modification of relevant product designs and the development of major components to facilitate the transformation of Taiwan’s relevant industries in the direction of high speed, high precision, specialization and multi-function. Moreover, it can enhance the industry’s international competitiveness and lower industrial costs to gain considerably. The experimental results showed that, during the static test with control factors including: Factor A (effective diameter: +0.03mm, +0.2mm, +0.5mm), Factor B (tightening-loosening velocity: 2rpm, 4rpm, 6rpm), Factor C (surface processing, cross grinding, finish turning level, concentric grinding), Factor D (thread pitch: 1.0P, 1.5P, 2.0P). Regarding the thread surface friction coefficient, sample of the tightening and loosening velocity at 2rpm, the thread pitch at 1.0mm and the effective diameter at +0.03mm had the best thread flank friction coefficient. The best parameter experimental value of thread flank friction coefficient improved by 14.48% as compared with the standard clasp locking high precision locknut. In the respect nut loosening ratio, concentric grinding high precision nut with thread pitch at 1.0mm, effective diameter at +0.03mm and velocity at 2rpm can obtain the best anti-loosening effects in the torque and axial force loosening test. The best parameter experimental value as compared with the standard clasp locking high precision locknut in terms of loosening ratio can improve by 9.41%. During the static tests with control factors including: Factor A (cutting velocity 800rpm, 1300 rpm, 1800 rpm), Factor B (cutter, titanium, ceramic, titanium plus ceramic), Factor C (effective diameter+0.03mm, +0.2mm, +0.5mm), Factor D (surface processing cross grinding , finish turning level, concentric grinding). To thread surface friction coefficient, using ceramic cutter with cutting velocity at 800rpm, effective diameter at +0.03mm in the torque and axial force loosening test of the clasp locking high precision locknut can have the best thread surface friction coefficient. The best parameter experimental value can improve by 1.4% in thread surface friction coefficient as compared with the standard clasp locking high precision locknut. Regarding the nut loosening ratio, in the torque and axial force loosening test of using ceramic cutter with cutting velocity at 800rpm, effective diameter at +0.03mm to process the clasp locking high precision locknut by concentric grinding, the best anti-loosening effects can be achieved. The loosening ration can improve by 3.12% as compared with the standard clasp locking high precision locknut. In dynamic tests, the best parameter combination was A3 B1 C1 D3 E1 F1 G1. Compared with the standard clasp locking high precision locknut in terms of the lapse rate, the lapse rate of the axial force can improve by 123.69%.In the respect of the nut loosening torque, the best parameter combination was A3 B1 C1 D3 E1 F3 G1. Compared with the standard clasp locking high precision locknut in terms of loosening torque, its loosening torque can improve by 123.78%.