1 Overview Bevel gear transmissions are widely used in the manufacture of automobiles, helicopters, machine tools and power tools. Different applications have different requirements on the performance and quality of bevel gears, and they include: 1 good contact area, reliable transmission of power torque; 2 good matching geometry, smooth motion transmission, so as to ensure uniform load, Smooth transmission, low vibration and low noise. The factory usually uses a double-gear meter and a rolling checker to detect contact spots to control the mass of the bevel gear, but it is actually difficult to accurately determine the bevel gear performance. 2 Main measurement methods and instruments for bevel gear accuracy 2.1 Coordinate geometry analysis and measurement methods and instruments Mechanical development into a straight bevel gear co-ordinate measuring instrument has a product earlier, represented by the Swiss Mag KP42 type, high precision but the structure is complex. Since 1990, the CNC gear measurement center was introduced to the market, and the coordinate arc bevel gear geometry error measurement method has developed rapidly and has been widely applied. The foreign gear measuring centers on the market today, whether it is the P63 from Klingelberg in Germany, the GMX275 from Gleason/Marl, or the Sigma 3 from M&M, all have the function of measuring bevel gears. These instruments have reached Class 1 of the VDI/VDE class, and the spatial measurement uncertainty is more than 2 microns; a single geometric error of the bevel gear can be detected, such as pitch deviation (including single pitch deviation, accumulative pitch deviation, Total accumulated tooth pitch deviation, tooth profile deviation (including total tooth profile deviation, tooth profile shape deviation, tooth profile inclination deviation), tooth direction deviation (including total tooth deviation, tooth profile deviation, tooth pitch deviation) Output three-dimensional shape of the surface shape deviation maps. 2.2 Integrated Measure Method and Instrument for One-Sided Mesh Rolling Inspection The bevel gear single-meshing rolling detection method has been used in production for many years. Taking the US Gleason N0.513 Rolling Inspection Machine as an example, under the condition that the measured bevel gear pair meshes with one side, the working state is simulated, a certain speed and load are added, V/H is adjusted, and a colored contact area (speckle) is performed The detection of the detected bevel gear pair is determined by the detection of the contact condition of the measured bevel gear pair; the vibration and the noise are measured by means of an acceleration sensor and a pickup, and the tooth-frequency harmonics are scanned and detected. This method belongs to the "quasi-dynamic" measurement method, which is incomplete and inaccurate for the accuracy detection of bevel gears. The bevel gear single-side meshing checker using an optical encoder as an angle reference for the detection of the tangential accuracy of the bevel gear, such as the PSKE900 from the Klingelberger GmbH of Germany, is particularly difficult to detect on the basis of the single test item. The adjustment of gear processing machine parameters is given guidance to improve the quality of bevel gear machining. The cost performance is poor, so it is not used in production. 2.3 Overall error measurement method and apparatus The overall error measurement of bevel gears integrates all individual geometric errors measured at each detection point on the working tooth face of the bevel gear into a bevel gear in the same rotation angle displacement coordinate. Based on the error map, and based on this, the bevel gear single-item geometric accuracy, comprehensive motion accuracy, and contact state of the bevel gear pair are analyzed and measured, and the performance and quality of the bevel gear are evaluated and monitored. The method and apparatus for measuring the overall error of bevel gears can be divided into two types. One is the coordinate geometry analytical measurement method, which is further divided into "point-to-point measurement method" and "spot scanning measurement method". The instruments used in both methods are CNC gear measurement centers, but they are equipped with measurement software packages. Different; the other is the meshing type motion geometry measurement (that is meshed point scanning measurement method, this method is our country's first), the instrument used is a bevel gear single-sided mesh checker, equipped with a dedicated measuring bevel gear And measurement software packages. 3 Conclusion By reviewing the status quo and development of bevel gear measurement technology in recent years, the overall error measurement techniques and methods of bevel gears at home and abroad are introduced and corresponding instruments are developed. The continuous development of the whole error measurement technology of the meshed point scanning bevel gear developed by our country has gradually been recognized by the domestic and foreign counterparts; the bevel gear overall error measuring instrument developed based on this technology is being pushed to the production line and continues to be perfected in the measurement practice. . It can be believed that, relying on the overall error measurement technology of meshing point scanning bevel gears, a database of mass accuracy products for bevel gears is established. It is entirely possible to use computer-aided measurement techniques to achieve automatic rapid pairing of bevel gears according to the requirements of use.
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The precision measurement method of the bevel gear is similar to that of the spur gear, which can be generally divided into three types: 1 coordinate geometric analysis measurement method. That is, the bevel gear is used as a geometric entity, and the geometrical elements of the bevel gear are individually measured for geometric accuracy. The gear measurement center is its main measuring instrument. 2 meshing integrated accuracy measurement method. That is, the bevel gear is used as a transmission element, and its transmission precision, contact spot, and vibration noise are comprehensively measured. The measuring instruments mainly include a bevel gear single-face meshing tester, a bevel gear double-face meshing measurer, and a bevel gear rolling tester. 3 Bevel gears overall error measurement method. It regards the bevel gear as a geometric entity for realizing the transmission function, or uses the coordinate measurement method to measure the overall error of the bevel gear in a single geometric accuracy measurement manner, and realizes the inherent connection between the single geometric error of the bevel gear and the transmission precision and quality. Analyze and study; Measure the whole error of the bevel gear according to the single-meshing measurement method and the meshing point scanning measurement method, and obtain the comprehensive motion accuracy, the contact spot, and the individual geometric accuracy of the bevel gear. Therefore, the overall error measurement method for bevel gears is the integration and development of the first two measurement methods.
With the development of coordinate measurement technology, computer control and measurement technology, the research on the whole error measurement technology of bevel gear has been rapidly developed in recent years. Due to the improvement of measurement performance and data processing capability of cylindrical multi-coordinate multi-function measuring instruments such as gear measuring centers, the coordinate geometry analysis technology of bevel gears has evolved from a single geometric error measurement to an overall error measurement of bevel gears, improving the cones. The level of the entire bevel gear manufacturing technology such as gear design, machining, accuracy and quality inspection and use performance prediction. The bevel gear single-meshing point scanning measurement technology developed by our country and based on the principle of “controllable point motion-geometry measurement†and the bevel gear integral error measuring instrument developed based on this technology are also moving more towards the production line. The practical application of our bevel gear measurement theory and measurement technology has been further improved and developed.
In recent years, the Phoenix 500HCT numerical control bevel gear rolling tester launched by Gleason Company has both the rolling inspection machine and the single-mesh engagement tester. It can not only measure the tangential composite error of bevel gears, but also can measure bevel gears digitally. Contact area, 3D structural noise analysis, etc. The advanced features of the model represent the contemporary level of development of this type of product. Although the price is expensive, there are individual users in the country. Similarly, there are CNC bevel gear inspection machines such as Klingerberg GKC60 and Olecon T50.
(1) Measurement of the overall error of the coordinate point-to-point bevel gear On the gear measurement center, three-dimensional probes are used to detect the tested tooth surfaces along the tooth profile and tooth direction of the bevel gear in predetermined directions. The geometrical errors of the points (usually 5 on the tooth profile and 9 on the tooth, for a total of 45 points) are measured little by little. This method can avoid the friction between the three-dimensional probe and the measured tooth surface during measurement and affect the measurement result. The measurement method adopts the principle of “direct measurementâ€. The specific steps are: Firstly, according to the adjustment parameters of the bevel gear machine tool and the geometric parameters of the tool, the geometric parameters of the ideal machining tooth surface of the processed large and small bevel gears are calculated; The tooth surface is used as the reference tooth surface and compared with the tooth surfaces of the large and small gears that are actually processed (or after heat treatment), and the geometric deviations of the actual tooth surface and the ideal tooth surface are measured. With the aid of the dedicated MATCH program, the imaginary machining parameters corresponding to the actual tooth surface to be measured are determined; then the TCA analysis is performed according to the meshing model to calculate the tangential integrated deviation and contact condition of the bevel gear pair and check whether the requirements are satisfied. If necessary, the corresponding software will recalculate and adjust the machine tool's processing parameters based on the measurement results so that when the test is repeated again, a more satisfactory product can be processed.
(2) Measurement of the overall error of the coordinate point scanning bevel gear The method proposed by Osaka Seiki, Japan, which uses a two-dimensional probe to perform spot scanning on bevel gear tooth surfaces, has yielded reliable and satisfactory measurement results. The method has the following characteristics: By controlling the rotation of the workpiece and the parallel displacement movement of the probe, the adverse effect of the friction between the probe and the tooth surface on the measurement is avoided; due to the use of the scanning measurement method, the measurement area can cover the entire tooth surface including The top of the tooth and the area close to the large and small end; the measurement path can have a variety of choices, usually 3 for the number of teeth and 3 for the number of teeth, a total of 6; the number of samples per scan line can reach 113 points, due to The high sampling density can reflect the tiny waviness on the tooth flute (which is often the main source of unpleasant noise and is difficult to measure with conventional point-to-point measurement methods). This method adopts the principle of “conjugation measurementâ€. The specific steps are as follows: Firstly, the geometric parameters of the ideal gear tooth surface of the large gear are calculated according to the machining parameters of the machine tool and the tool parameters, and the virtual conjugated with it is calculated. The flank geometry parameters of the conjugated pinion gear; the actual processing of the large gear tooth surface and the ideal machining large gear tooth surface are compared and measured to detect the relative deviation of the tooth profile and the tooth up; the actual processing of the pinion tooth surface and the calculation The virtual conjugate pinion tooth surface is compared for measurement and the relative deviation of the tooth profile and the tooth direction is detected. According to the measured relative deviations, the three-dimensional tooth profile comprehensive deviation topography of the bevel gear pair, tangential comprehensive deviation and contact form (including contact path, contact area shape, size and position, etc.) are calculated. Through physical measurement and comparison verification, the measurement results of the point-to-point measurement method and the spot scanning measurement method are consistent.
(3) Measure the overall error of the meshing point scanning bevel gear The bevel gear meshing point scanning measurement method proposed by Chengdu Tool Research Institute is on the bevel gear single-side meshing inspection instrument, according to the design installation position, using special measurement bevel gears and Measured bevel gears perform single-mesh rolling measurements. The "basis" geometry of this measuring bevel gear pair is exactly the same as the geometry of the bevel gear pair being measured. During the measurement, the method of etching or pasting is used to make the required tooth profile or tooth-direction measurement ridge on the gear teeth between the large and small measurement gears, and to match the tooth profile or tooth-to-measurement ridge line of the bevel gear. The measured bevel gear tooth surface contact transmission completes the overall error measurement of the meshing point scanning of the bevel gear. The number of measuring paths is related to the number of measuring gear teeth, which is generally 3 + 3 in total. The overall error measurement of bevel gear meshing point scan uses the principle of “local reference relative measurementâ€. The specific measurement steps are as follows: According to the actual sports car/trial test (or experience) of the bevel gear pair, the factory selects the bevel gear pair that best meets the requirements for use as the “reference†bevel gear pair (called the local datum). The tangential composite deviation, one-tooth tangential composite deviation and contact zone morphology were confirmed as the main reference indicators for evaluating the accuracy of the pair of bevel gear pairs. Measure the bevel gear and the local reference bevel gear to mesh. Measure the comprehensive tooth profile deviation test on the bevel gear single-mesh engagement tester (measurement of the local reference bevel gear pair - measure the reference bevel gear pair, the same below), and comprehensive tooth deviation Bureau-test, tangential comprehensive deviation bureau-test, one-tooth comprehensive deviation bureau-testing, contact zone morphology bureau-test and three-dimensional tooth profile comprehensive deviation topography map-test etc., and confirmed as batch bevel gear detection The reference data of the main accuracy index of this single bevel gear. The measured workpiece bevel gear and measuring bevel gear are measured in the same way to obtain the deviation of the workpiece bevel gear-measuring bevel gear data; the corresponding deviation work-field data is obtained through operation (ie, the workpiece bevel gear is relative to the local reference cone The deviation of the corresponding accuracy of the gear). Then, according to the measured work-site deviation data and the established precision index tolerance range, the bevel gear quality and interchangeability level are determined.
The method of measuring the overall error of bevel gears is simple, fast, reliable, and rich in measurement information. It is especially suitable for mass production. Because special measurement gears must be used for measurement, this measurement method is not suitable for single-piece, small-batch measurements. However, since the bevel gear overall error measuring instrument also has the function of a bevel gear rolling tester, it can be fully used for the single-piece small batch bevel gear pair's comprehensive precision detection and mass production of the workpiece's test cutting and machine debugging.