Study On Double Flank Testing Technology For Fine-pitch Bevel Gears

As the era of intelligence comes,fine-pitch gear also starts to shine.Although finepitch gears have played an irreplaceable role in many fields such as precision machinery,instruments,aerospace,medical devices,electronic products,etc.,with the advent of 5G,internet of things and the era of intelligence,service robots,IT equipment,communications,smart home,smart city and other fields have a huge demand for micro-transmission systems,fine-pitch gears as micro-transmission.The importance of the key basic components of the system will be more and more obvious.The quality of fine-pitch gears often directly determines the operation performance,service life,safety and reliability of the system.At present,fine-pitch gears are developing in the direction of high precision,high efficiency,high reliability,long life and low noise.However,as the main way to detect the quality of fine-pitch gear,the measurement of fine-pitch gear,especially the measurement of micro gear,has always been a difficult problem in the gear industry.Compared with fine-pitch cylindrical gears,the measurement of fine-pitch bevel gears is more difficult.So far,it can be said that there is a lack of necessary instruments.Aiming at the urgent need of fine-pitch bevel gears used in dental handpiece,this paper develops a dual-rod comprehensive measurement technology for fine-pitch bevel gears.The maximum output speed of dental handpiece is 200,000 revolutions per minute,which consists of two-stage "orthogonal" and "non-orthogonal" speedincreasing bevel gear pairs.The bevel gears are small in size,high in speed and low in noise.The lack of measuring means has been restricting the quality improvement of dental mobile devices in China.The instrument developed in this paper solves the detection problem of small modulus bevel gears for dental handpiece.The main work accomplished in this paper is as follows:(1)Measuring scheme-According to the structural characteristics of bevel gear transmission system of dental handpiece,based on the analysis of measuring force,a comprehensive measurement scheme of small modulus bevel gear pair is proposed.The main machine is a horizontal structure.Stepping motor drives the fine-pitch bevel gear pair to engage in two-sided motion.The force sensor monitors the measuring force.One grating sensor is used to measure the two-sided motion.The other grating sensor is used to determine the initial position of the gear pair.The whole measuring process is completed automatically.(2)Measurement and control system-Based on the technology of "ARM + FPGA",a motor control,signal processing and Ethernet communication system for the integrated measurement of double-rod of fine-pitch bevel gear pair is developed.Two grating signals are received by differential circuit,and the real-time acquisition and display of gear position signals are realized by the subdivision and direction discrimination of the FPGA.The force signal is collected by FPGA through A/D conversion circuit,and the force value is displayed in real time.By communicating with FPGA,ARM can set the sampling frequency of grating,A/D sampling frequency and the dividing coefficient of motor driving pulse,and then realize the precise control of stepping motor.(3)The software of double-rod measurement for fine-pitch bevel gear pair has been developed,which has various functions such as measuring process control,data processing,error display and network communication.(4)Experiments-Based on the double-rod measuring system of fine-pitch bevel gear pair,the actual test of fine-pitch bevel gear pair of dental handpiece was carried out.The test results show that the developed system is reliable and can realize the comprehensive testing of double-rod of fine-pitch bevel gear pairs.