The gear motion error curve assumes that the driving wheel is an ideal gear with no error. The driven wheel is the actual gear with error. The gears of the two gears are equal. When the driving wheel rotates the angle error 45b, 90b, 135b, 225b, The moving wheels are rotated through the same angle in turn, but since the tooth distribution is uneven, there is a corner error with respect to the wheel angle (the middle dotted line position) at each position.
The sources of gear motion errors are mainly geometric eccentricity and motion eccentricity. Geometric eccentricity is caused by the error of the tooth blank itself when the tooth is cut or the misalignment of the gear reference hole with the center of rotation of the hobbing machine table. Different from geometric eccentricity, when the gear is processed by the principle of development, the gear transmission chain from the tool to the tooth blank should maintain the accuracy of motion according to a certain transmission ratio. These transmission chains are composed of a series of transmission components ( Gears, worm gears, etc., the manufacturing and assembly errors must be reflected in the end of the transmission chain during the transmission movement, resulting in non-uniformity of relative motion. Therefore, the eccentricity of motion is only equivalent to eccentricity. Since the left and right tooth profiles are simultaneously formed when the teeth are cut, the radial position of the cutter relative to the tooth blank is unchanged, and the points of the left and right tooth profiles are simultaneously cut out with the same increment of the meshing line, and the directions are opposite, and the formed radial position of the tooth profile is unchanged. And tangential error occurs along the circumferential tangential direction.
Optimization calculation In the actual transmission process, the fundamental wave of the gear angle error curve changes sinusoidally, and the maximum rotation angle error occurs only once in the gear. This maximum corner error reflects the actual gear motion error. It can be attributed to the meshing line of the gear drive for calculation. The mesh line increment is a comprehensive reflection of all the gear errors and is a function of the gear angle. When there are multiple errors at the same time, the geometric eccentricity e generated by the tooth blank when cutting the tooth can be calculated by the square root of the square sum, ie: e=Ee2i(1) where: the Zibo electric drum ei is the independent original error Maximum value.
If the gear rotates counterclockwise through an angle U, the increment of the mesh line caused by the geometric eccentricity can be calculated by the projection of e on the meshing line, ie: $F = e sin(A0 U) (2 Where: A0 is the tooth angle, equal to the index circle pressure angle Af. The eccentricity of the motion is that the base circle of the gear is not eccentric with respect to the matching hole, but the radius of the base circle of each moment is different, and the generated motion eccentricity can be calculated by the equation (3): e transport = 12 $ UE worm r0 (3) Where: $UE is the maximum angle error of the indexing worm wheel; r0 is the base circle radius of the gear to be machined.
At this time, the increment of the meshing line is: $F transport = e transport sinU (4) a pair of gear mesh with error, the maximum corner error value caused by the different meshing starting points is different, select different starting points for measurement By selecting the minimum angle error curve for meshing, the movement accuracy of the gear can be greatly improved. For this reason, when the gear is assembled, eight different starting meshing points can be selected for the measurement of the tangential integrated error, and the curve with the smallest corner error is selected as the meshing position of the gear pair. In the transmission process, a certain rotation angle error will be generated every time one tooth is rotated. The MATLAB software is used to program the motion error curve, and the maximum rotation angle error of all the gear transmissions is calculated, and the error value is selected from the smallest. As a meshing point.
According to the gear accuracy grade, it is simple and convenient to consider the work site at the same time. The gear teeth in the eight positions shown are taken as sampling points for measurement. The drive is divided into 4 units, and the internal gears are optimized and matched. The method is as follows.
1) The gear 1 meshes with the gear 2, and the Caesar air compressor uses the gear 1 as the driving wheel to rotate in the direction of the gear 1 shown, and measures the tangential integrated error curve of the first meshing point of the gear 2 and records it, and then rotates 45b each time. Measure once and select the curve with the smallest tangential integrated error. 2) Take the gear 3 as the driving wheel, rotate in the direction of the gear 3 shown, the gear 4 is the passive wheel, measure once every 45b, and select the curve with the smallest tangential integrated error. 3) By analogy, find the curve with the smallest tangential error of the 5 and 6, 7 and 8 gears. The starting point is the minimum error curve between the four units of the meshing point.
It can be seen from these corner error values ​​that the maximum corner error of the gear meshing transmission can be reduced to 20Lm. After optimized design, the accuracy of gear and transmission accuracy is improved, the printing quality is guaranteed, the number of adjustments is reduced, and the adjustment difficulty is reduced. Thereby, the startup preparation time is greatly shortened, the production efficiency is improved, and the maximum benefit is achieved while facilitating the worker's operation.
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