Views: 0 Author: Site Editor Publish Time: 2022-10-07 Origin: Site
Although the principles of gear measuring centers in various countries are much the same, there are still some differences in the implementation methods. It is mainly shown in:
(1) In terms of measuring sensors, although high-precision circular gratings are generally used for angle measurement, length measurement varies with different objects. For gears with high accuracy requirements or workpieces with long axial dimensions, dual frequency (or single frequency) laser interferometer is generally used as the length reference (such as measuring involute or spiral template); In other cases, high-precision long gratings are used.
(2) In terms of the accuracy of mechanical systems, high-precision bearings are necessary; The precision of linear guide rail is guaranteed by mechanical precision, and it is also achieved by error correction technology.
(3) In terms of numerical control system, NC open-loop control was often used in the 1970s; After the 1980s, they were all CNC controlled, mostly DC servo motors or stepping motors. At present, AC servo system or linear motor has been adopted.
(4) In terms of the probe, there are inductive type and grating type; There are one-dimensional, three-dimensional and even rigid. The rigid probe is not equipped with a micrometer sensor. If a rigid probe is used, the instrument is usually dedicated.
The gear measuring center is generally composed of host, CNC numerical control unit, data acquisition unit, communication interface between machines, computer and peripherals, measurement software and data processing software. The main features of the latest CNC gear measuring center are: ① High efficiency, high precision and easy operation. The measures taken include optimization design of precision machinery, 32 bit CNC 4-5 axis numerical control system, linear motor, 3D probe and error correction technology. ② In terms of functions, it includes the measurement of major error items of rotary parts such as gears (internal and external), gear cutters (hobs, gear shapers, gear shavers), bevel gears, worm gears, worms, screws, convex gears, broaches, etc; Geometric tolerance measurement of shaft parts; Strong analysis functions, such as contact analysis, process error analysis, tooth root shape analysis, parameter reverse analysis, etc; It can be coupled to the machining system for real-time data communication. ③ In terms of maintainability, it has the ability of fault self diagnosis and network remote fault diagnosis. ④ Upgradeability. It includes software upgradeability and hardware upgradeability.
Compared with the mechanical generative measuring instrument, the advantages of CNC gear measuring center are self-evident. Its qualitative leap is to make it possible to measure the tooth profile of any shape, not just the involute or linear tooth profile. The measurement of bevel gear, K worm (hob) and C worm (hob) is proof. CNC gear measuring center provides a tool for measuring and controlling nonlinear spiral surface.
Since 1990, several noticeable phenomena have appeared in the field of gear measurement technology worldwide: ① the integration of gear overall error measurement technology and gear coordinate measurement technology. Chengdu Tool Research Institute has launched a gear measuring machine CZN450 with both standard worm and measuring head, and foreign CNC gear measuring centers can also provide "virtual global error". ② The combination of gear measuring center and CMM, such as Rdiance of TSK Company and ND430 of Process Equipment Company. ③ Combination of functional test and separate test. Simplifying measurement is one of the development trends of gear measuring instruments. The gear overall error measuring instrument is accepted by the gear manufacturing industry because it can give full information of gears efficiently.
Looking forward to the future, the focus of research and development of gear measuring instrument is: gear network measurement technology; Virtual analysis technology of gear performance based on measured results (intelligent pairing, dynamic performance prediction, etc.); Gear overall error measurement technology (index quantification, performance optimization, etc.); Intelligent analysis technology of gear error; The establishment of the concept system of gear statistical error and its corresponding measurement technology; Fast measurement and analysis technology of gears on the production site (at present, the model 4823 of ITW is 450-600 pieces/hour; the target is 1000 pieces/hour); Application of precision machinery, photoelectric technology, microelectronics technology, software engineering and other technologies in gear.
