| 主权项 |
1. An error measuring method of gear comprising following steps:
providing a gear pair and a single gear flank testing device, the single gear flank testing device having an operation unit, the single gear flank testing device performing single gear flank testing of the gear pair for obtaining transmission error data used to produce a testing signal graph; the operation unit decomposing the testing signal graph by means of an Empirical Mode Decomposition (EMD) to generate a plurality of intrinsic-mode-function graphs (IMFs); the operating unit selecting a first function graph and a second function graph from the intrinsic-mode-function graphs (IMFs) wherein the first function graph fluctuates with a first frequency value falling into a first numerical range, and the first frequency value is most close to a meshing frequency of the gear pair, while the second function graph fluctuates with a second frequency value falling into a second numerical range, and the second frequency is most close to a rotational frequency of the gear pair, and wherein a value falling into the first numerical range is greater than a value falling into the second numerical range; the operation unit selecting a plurality of third function graphs from the intrinsic-mode-function graphs (IMFs), so that the first function graph is among the third function graphs, wherein each of the third function graphs fluctuates with a corresponding third frequency value that falls into a third numerical range, and a value falling into the third numerical range is greater than the value falling into the second numerical range but not greater than the value falling into the first numerical range; the operation unit combining the third function graphs to produce a graph of superposing function, the graph of superposing function having a plurality of wave crest values; the operation unit calculating a plurality of single pitch errors of the gears errors based on a difference of the wave crest values in the graph of superposing function for every pair of adjacent pitches, and calculating a plurality of adjacent pitch errors of the gears and an accumulated pitch error of the gears based on the plurality of single pitch errors, wherein the adjacent pitch errors of the gears are defined as a difference in single pitch errors the gears for every pair of adjacent pitches, and the accumulated pitch error of the gears is defined as a combination of every single pitch error of the gears for all pitches; the operation unit measuring the amplitude of the first function graph to obtain a profile error of the gears and measuring the amplitude of the second function graph to obtain a deflection error of the gears; and the operation unit transforming the profile error of the gears, the deflection error of the gears, the single pitch error of the gears, the adjacent pitch error of the gears and the accumulated pitch error of the gears into a definition of a gear precision of the gear pair. |
