A detection method for the directionality of the grinding corrugation of the crankshaft journal

Abstract

The invention discloses a method for detecting crankshaft journal grinding wave directions. Under the condition that size precision and surface roughness meet a drawing, the directions of waves of crankshaft journal machined through an end face numerical-control grinder are detected. A Dacron sewing thread is used for hanging a weight which is 10+ / -1 g on a crankshaft journal, the length of the Dacron sewing thread is limited, the best length of the Dacron sewing thread enables a contact arc which is 220-240 degrees to be formed by the Dacron sewing thread and the crankshaft journal, the forward direction rotating speed v of the Dacron sewing thread is maintained to be small than or equal to 70 r / min, and therefore the simple thread hanging test method is used for detecting the directions of grinding waves of shaft type parts. The method has the advantages of being low in input cost, convenient to operate, simple, practical and high in accuracy.

Description

technical field [0001] The invention relates to a detection method, in particular to a detection method for the directionality of crankshaft journal grinding corrugations, which belongs to the field of crankshaft machining. Background technique [0002] Grinding crankshaft journals with ordinary crankshaft grinders is a commonly used finishing method in domestic small and medium-sized crankshaft manufacturing enterprises. The surface roughness of the crankshaft journal processed by this method can reach Ra0.4-Ra0.8, and the precision level can reach IT5-IT6 level, which can meet the process requirements of conventional products. In the long-term production practice, it is found that the grinding surface of the crankshaft will produce grinding ripples. This defect directly affects the assembly of the engine. For example, it will cause oil leakage from the sealing ring and reduce the performance of the engine. This problem also exists in the single-cylinder crankshaft we prod...

AI Technical Summary

Problems solved by technology

In the long-term production practice, it is found that the grinding surface of the crankshaft will produce grinding ripples. This defect directly affects the assembly of the engine. For example, it will cause oil leakage from the sealing ring and reduce the performance of the engine.

This problem also exists in the single-cylinder crankshaft we produce. Even if the end-face CNC grinding machine that has been promoted in recent years is used, the sealing ring at the output shaft end will also have oil leakage due to the corrugation on the journal surface. The phenomenon reduces the performance of the engine, leaving hidden dangers of accidents, and for the crankshaft manufacturer, it is to bear the risk of claim handling from the engine customer or even losing the market, so how to find out the problem early in the product production process and deal with it is the crankshaft production The primary task that manufacturers must face correctly at present

However, eliminating grinding ripples is a difficult problem. First, it is affected by the geometric accuracy of the machine tool; second, it is affected by factors such as the forced vibration of the machine tool and the self-excited vibration of the motor; and the third is the balance problem of the crankshaft itself.

Therefore, the thinking direction of eliminating grinding ripples was changed. After long-term research and testing, the current end face CNC grinding machine can fully meet the requirements of use when the dimensional accuracy and surface roughness can meet the drawings. The existence of surface waviness generally does not affect the crankshaft. For individual shafts, as long as the directionality of corrugation can be detected and improved, but there is currently no general instrument for detecting the directionality of corrugations on the surface of shaft parts, and high-end CNC grinding machines are used regardless of production costs. And CBN grinding wheel, imported testing equipment are unrealistic

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