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Screw drive design and test parameters

- Blue - △ mouth 2sin tan so with three-pin diameter measurement in the final result obtained by the following formula d2 d2 +24.3 screw pair with a diameter consistent with the experience of tolerance and understanding 58 * 2006 26, No. 5 relaxed diameter tolerance, increased tolerance of the diameter consistency,[link widoczny dla zalogowanych], of course,[link widoczny dla zalogowanych], reduces the difficulty of sub-processing screw, but in order to screw and nut with axial play after the meet the design must be single with screw nut, This reduces the interchangeability, or even no interchangeability, improvements need to take certain measures, such as the use of double nuts to adjust. With the increased processing capacity and means, should give priority to maintain the interchangeability of parts. 4.4 Axial tooth thinning with the amount of clearance and to ensure the backlash, the need for screw and nut tooth thinning, as mentioned above, in accordance with the uniform distribution, screw or nut thinning the amount of tooth △ A / 2mm, from a practical point of view, should be considered such as strength of the screw and nut design. The main failure mode of screw pair is worn, usually screw longer than the nut, which nut wear faster. To the design, for example, the length of the screw and nut than 44, consider the material and heat treatment and processing methods and other factors, in theory, the wear rate is the screw nut 30 times more, that screw on the wear of the tooth thickness 0.1mm, 3mm wear at least over the nut. Therefore, the design should be the amount of tooth thinning on the screw, while the nut tooth thickness thinning as much as possible, or even have to consider thicker. 5 Summary In this design, using a long sliding screw drive mechanism. From the requirements and economic and other aspects, this paper analyzes in depth the design parameters of the screw pair and mutual relationship between the screw design and test the same time easy to confuse the concept in the analysis,[link widoczny dla zalogowanych], various design parameters on a reasonable matching, to reduce technical risk and processing difficult to meet the requirements of the goal. References [1] Kim Guan Liang, gold in the rich. Thread processing and measurement manual [M]. Beijing: National Defence Industry Press, 1982. [2] Zhao Xun expensive. Thread grinding [M]. Beijing: Mechanical Industry Press, 1989. [3] Liu Nian Zhao,[link widoczny dla zalogowanych], et al. Interchangeability and Technical Measurement [M]. Beijing: China Metrology Press,】 986. (Continued from page 46) Table 3K extended weighted arithmetic mean K d 6 relative uncertainty of the calibration results are given in Table 4 Comparison of the Great Wall in Beijing Institute of Measurement and Testing Technology (CIMM) and NASALFPL the results of the comparison. Table 4CIMM comparison of the results with the NASALFPL sensor CIMMNASALFPL comparison type (a) / K ID number of a table, = (Kl + K27 / 2. 7 discussions 1) Table 1 shows the correction factor K radiation temperature sensor calibration results of partial data . By a given part of the calibration results can be seen, the radiation error of △ 71 size, with the Mach number, temperature and wall temperature thermocouples, etc. restoration differ, generally with the flow Mach number, wall temperature decreases and the thermal Even restore the temperature increases. The radiation correction factor in each group is different K, and their uncertainty is not the same, therefore, need to come to each thermocouple weighted method of radiation correction factor K. 2) can be seen from Table 2, in different states, the temperature sensor correction factor K radiation relative combined standard uncertainty and the relative expanded uncertainty of different sizes, K Sweet relative expanded uncertainty of 0.09 ~ 0 .34 between. Uncertainty of the size of many factors, but mainly the size of radiation error △, generally when △ is small, the larger uncertainty. When we converted K relative expanded uncertainty of recovery temperature of the thermocouple pairs' effect sizes, we found that the relative error of 71, 0.6 ~ 0.8, is smaller. In calculating the correction factor when the radiation temperature sensor, were weighted to make it more reasonable and accurate calculations. Weighted average of the radiation correction factor relative expanded uncertainty of less than 0.12. 3) can be seen from Table 4, for A, A and 9 bare thermocouple, CIMM and the average between comparison, the absolute value of the ratio between 0 to 0.6; for B and 9 shielded thermocouples, the ratio was 3.5. If these results shall be converted radiation error △ 71 pairs of values, a difference of 2C is also within very small. 8 Conclusion The size of K relative expanded uncertainty arising from the temperature of the thermocouple 71 of recovery, a difference of only 0.6% ~ 0.8; with the United States NASALFPL compared the results between the two close to the level of good . So that, in our thermal calibration wind tunnel,[link widoczny dla zalogowanych], on the bare thermocouple, shielded thermocouple calibration of the radiation correction to be accurate and reliable.

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