At present, in the design of the general multi-axle box of the combined machine tool, when the gear modulus is manually determined, it is generally determined by the analogy method, or estimated by the formula, ie (30~32)p, P is the power transmitted by the gear, the unit is kW, Z The number of teeth of a pair of meshing gears, n is the speed of the pinion, the unit is r/min. Then, after the whole transmission system is drafted, the selected gear module is verified to check whether the work requirements are met. Because the checking is more annoying, generally only the gears that bear the most load and the weakest are checked. In the years of design practice, the author believes that the above methods have shortcomings. The rationality of the gear modulus determined by the analogy method obviously lacks quantitative evaluation, and the results obtained by applying the above estimation formula sometimes have a large deviation from the specific check result, and are also inconsistent with the actual use results. In addition, the above estimation formula needs to be improved in practical application convenience.
On the basis of analyzing the specific design of the general multi-axle gear of the combined machine tool, a set of special simplified design formulas for determining the gear modulus is recommended to improve the manual design quality, which can avoid the trouble of checking the check and can be used for the general multi-axle manual. Design review assessment. At the same time, it can also provide some experience for current computer-aided design.
2Special Simplified Design Formula 21 A brief analysis of the current estimation formula m>(30~32) The gear modulus estimation formula (0~32)g introduced in the current data is a simplified design of the general mechanical gear after roughly simplifying many parameters. Formula, the accuracy of the calculation results is poor; and the formula is based on the cubic root relationship, which is also affected by the simplified design formula of the general mechanical gear; in addition, the p (the power transmitted by the gear) is used as a parameter, which is not convenient for the actual design. Application, this is especially true for gear designs on the drive shaft.
The selection of 22 special simplified design formulas The gears used in the general multi-axis box of the machine tool are hard-tooth spur gears. The gear tooth surface has high contact strength and the tooth root bending strength is relatively low, and the lubrication and cooling conditions of the gear are better. Pitting corrosion occurs. The main and most dangerous form of failure is the bending and breaking of the gear teeth. Therefore, when designing the gear manually, it is more suitable to select the calculation result of the tooth root bending fatigue strength as the design basis. The calibration formula = <0 zhong, convertible two Y2 S obviously has a design formula m>: 1999-07 23.2 composite tooth profile Yfs combination machine tool universal multi-axle gear teeth number Z range of 16~70, the general preferred range is 18~50, the corresponding corresponding value is: By comparison analysis, the Yfs value is inversely proportional to the Z value; and as the Z value is large, the Yfs value becomes smaller. Due to the large data dispersion of this parameter, Yfs=4.45~4.00. 23.3 Gear tooth width b When using 1T074142 gear series, b=24mm When using 1T074141 gear series, b=32mm 23.4 Allowable bending stress ofp combined machine tool The material used for the axle box gear is 45 steel. The technical requirement is that the gear is high frequency hardened with G54 accuracy of 7 grades. The relevant data, combined with the actual production, are as follows: intermediate gear (two-way force) = print as = 340MPa24 Derivation of the simplified design formula. Substituting the calculated values ​​of the above groups into HYF, and paying attention to the unit of T value from Nmm Nm, it is not difficult to draw the special simplified design formulas in the various situations listed in Table 1: Table 1 gear usage gear tooth width (select gear series) general gear drill down expansion hinge type multi-axle box gear intermediate gear general gear tapping In order to facilitate the rounding of the formula data, the multi-axle gear intermediate gear is compared with the original estimation formula, and the simplified design formula of the above table is changed into the form of Table 2.
Table 2 Gear usage Gear tooth width (select gear series) Drilling expansion hinge type multi-axle box gear General gear intermediate gear tapping type Multi-axle box gear General gear intermediate gear table listed in the special simplified design public range factor, is Determined by the number of gears used, the value of the number of teeth is small, and the number of teeth is small. For specific application characteristics, see 2.3.2 Compound tooth coefficient Yfs entry.
3About the characteristics of the design of the multi-axis box gear modulus of the tapping type. When designing the multi-axle box of the tapping type, the influence of tap passivation should be taken into account, and the T value (or P value) of the special simplified design should be correspondingly Correction, combined with the proposed characteristics of the multi-axle transmission system of the combined machine tool, generally can be: T correction = (1.5 ~ 2.5) TT value correction coefficient and the number of taps driven by the gear, this paper is recommended as shown in Table 3.
Table 3 The number of taps transmitted by the number of taps is more than 8 T-value correction coefficient (edit Zhang Xinlong) bZFp, K is the load factor; T is the torque transmitted by the gear, the unit is Nmm; Yfs is the composite tooth profile; b is the gear tooth width , the unit is mm; Z is the number of gear teeth; Ffp is the allowable bending stress of the material used for the gear, the unit is MPa (or N/mm 23 The calculation parameters are determined according to the working characteristics of the common multi-axle gear of the combined machine tool, can be divided into There are two categories and four sub-categories: one is a multi-axle gear with a drill-and-spinning hinge; the other is a multi-axle gear with a tapping type. The two types of multi-axle gears are also divided into general gears. Force) and intermediate gear (two-way force). Therefore, when determining the relevant calculation parameters, it is necessary to classify and select.
23.1 Load factor K drill expansion joint type universal headstock gear load factor:
Synchronizer Key,Gear Key,Transmission Synchronizer Key,Gear Synchronizer Key
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