基于FBG的齿根弯曲应力在线检测方法

根据国际标准化组织(international organization for standardization,简称ISO)和美国齿轮制造者协会(American gear manufacturers association,简称AGMA)关于渐开线圆柱齿轮强度的计算方法,在计算单个齿轮齿根弯曲应力时,可将轮齿简化为一悬臂梁。基于此,提出了一种齿根弯曲应力在线检测的新方法,利用光纤布拉格光栅(fiber Bragg grating,简称FBG)的应变特性和齿轮传递扭矩时轮齿产生的挠度,将齿根弯曲应力的测量转化为光栅反射波长的测量,通过对反射波长的实时解调,能够实现对运行中齿轮的齿根弯曲应力进行实时在线检测。通过对一对渐开线圆柱尼龙斜齿轮进行分析,并在1~18N·m扭矩范围进行实验,结果表明该方法能够准确测量齿根的弯曲应力,灵敏度高达70pm/MPa,线性拟合度达0.99以上,且响应速度快。利用光纤光栅准确检测齿轮运行时的齿根弯曲应力,不但能够代入实际工况实现在线检测,同时对齿轮的设计和故障诊断具有指导意义。

Study on the Method of On-Line Detection of Bending Stress of Gear Tooth Based on FBG

This paper puts forward a new type of on-line detection for the gear tooth root bending stress by real-time demodulation of the grating reflection wavelength. The proposed method is based on the strain characteristics of fiber Bragg grating (FBG) and the deflection that gear teeth produce under the force. The experiments are carried out on a pair of involute cylindrical nylon gears and the results are obtained when the torque ranges from 1 to 18 N·m. The sensitivity is up to 70 pm/MPa and the linear fitting degree is above 0.99 when the tooth root bending stress is measured with fast response. The high accuracy implies that FBG is able to be used to detect the running gear tooth root bending stress under the real condition, which has a guiding significance on the gear design and fault diagnosis.