Wafer type ultrasonic non-destructive testing probe for low-modulus gear root residual stress

Abstract

The invention provides a wafer type ultrasonic non-destructive testing probe for a low-modulus gear root residual stress. The method can be applied to non-destructive testing for gear root circumferential residual stress, combines an ultrasonic non-destructive testing system with a piezoelectric wafer and a wedge block, stimulates critical refraction longitudinal waves which are most sensitive to the residual stress nearby the root, and accurately calculates the residual stress at the area according to a sound time difference of the critical refraction longitudinal waves between the stress situation and non-stress situation nearby the root. The method can accurately, quickly and non-destructively test the low-modulus gear root residual stress.

Description

1. Technical field [0001] The invention proposes a method based on the acoustoelastic principle to directly generate critical refraction longitudinal waves by piezoelectric wafers to realize the non-destructive detection of the circumferential residual stress of the tooth root of the gear, and the method is suitable for the non-destructive detection of the circumferential residual stress of the tooth root of the gear. 2. Background technology [0002] Gear is an important part of mechanical equipment to transmit power. It is responsible for the important tasks of transmitting torque, power and movement. The residual stress of gear tooth root has an important impact on the manufacturing quality, carrying capacity, safety and reliability of use and service life of gears. The mechanical processing and heat treatment process of gears in the forming process will cause residual stress in the tooth root, and the cyclic working load will also force the tooth root to produce residual ...

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Problems solved by technology

[0003] After searching the literature of Wanfang and HowNet, it was found that the paper: (Zhao Xiyong. Determination of tooth root stress of worn traction gear [J]. Locomotive Electric Transmission, 1985:19-26) mentioned the method of attaching strain gauges to Measuring the stress of the dedendum, but this method is limited to monitoring the dynamic stress on the side of the dedendum during the movement of the gear, and cannot detect the residual stress caused by the manufacturing and service fatigue factors of the dedendum.

Patent: (Jiang Chuanhai, et al. Detection method for residual stress of shot peening layer at the root of small curved gears [P]. Patent No.: CN102628815A, 2012) discloses a rectangular diffraction baffle with different sizes prepared according to the curvature radius of the gear. Under the condition of the baffle, use the method of X-ray diffraction to detect the residual stress value of the root of the curved surface gear, and obtain the relationship between the width of the rectangular baffle and the residual stress value. This is a stress detection method based on X-rays, which requires the gear tooth root The surface is basically flat and must undergo appropriate chemical treatment to expose the crystal lattice, and the incident angle of X-rays must be adjusted repeatedly to obtain a certain intensity at a suitable diffraction angle. The operation is complicated, there are many influencing factors, and the accuracy is not good. High, and can only detect the residual stress on the tooth root surface, the practical application is greatly limited

Patent: (Xu Chunguang, Jin Xin, etc. An ultrasonic non-destructive testing method for measuring the circumferential residual stress of gear tooth roots [P]. Patent No.: CN103808806A, 2014) discloses a method using traditional ultrasonic transducers and wedges The block method is used to measure the residual stress of the tooth root. This method can only be used to measure the residual stress of gears with relatively large modulus. For gears with small modulus and small cogging spaces, traditional ultrasonic transducers cannot be used.

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