Multi-axis stress state dynamic friction coefficient measuring device suitable for tube expansion forming processing

Abstract

The invention relates to a device for testing dynamic frictional coefficients, which is applicable to the multi-axial stress condition in the shaping process of pipe expanding and belongs to the technical field of material processing. The device comprises a digital control machine tool holder, a frictional head, a hard rubber pad, a specimen fixing platform, a fixing platform support, a piezoelectric sensing platform of a three-phase dynamometer, a charge amplifier and an A / D collecting computer, wherein the frictional head is arranged under the digital control machine tool holder, testing specimens are fixed on the specimen fixing platform through the hard rubber pad, the specimen fixing platform is arranged on the fixing platform support, the lower end of the fixing platform support is provided with two swallow-tail shape surfaces which incline downward swallow-tail shape slots are arranged on the two inclined surfaces along the inclined direction, the upper portion of the fixing platform support is an upper inclined surface which is matched with the specimen fixing platform, swallow-tail shape bosses are arranged evenly on the upper inclined surface along the inclined direction, the swallow-tail shape bosses are matched with the swallow-tail shape slots, the fixing platform support is fixed on the piezoelectric sensing platform, and the piezoelectric sensing platform is connected with the A / D collecting computer through the charge amplifier. The invention has simple structure, convenient operation, high accuracy and strong versatility.

Description

technical field [0001] The invention relates to a device in the technical field of material processing, in particular to a device for measuring dynamic friction coefficients in a multi-axis stress state in pipe expanding and forming processing. Background technique [0002] In the material forming process, the pipe expansion forming method is a relatively common material forming method, but due to the mechanical relative movement between the mold and the inner surface of the pipe fitting during the pipe expansion process, and the plastic flow of the deformed metal, the expansion process In the tube forming process, the friction coefficient between the mold and the inner surface of the formed workpiece is a key parameter of the forming process. Inaccurate friction coefficient values ​​will lead to poor friction and lubrication state during the material forming process, which will easily cause defects such as product size out-of-tolerance, surface quality not up to requirement...

AI Technical Summary

Problems solved by technology

Its shortcoming is that it cannot measure the dynamic friction coefficient under multi-axial stress state, and the mechanical inertia measurement is used. During the measurement process, due to repeated surface wear, there is a large amount of contact heat, resulting in unstable values ​​and low accuracy.

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