Vibration Testing of Poppet Valve Based on Virtual Binocular Vision

The vibration of the spool caused by the change of the medium flow near the spool of the hydraulic valve has an important influence on the stability and service life of the poppet valve. In order to investigate the three-dimensional vibration characteristics of the poppet valve, this paper proposed a visual experiment method based on virtual binocular vision, and obtained the image sequence of the valve core vibration. The spatial coordinate value of the geometric vertex of the spool was obtained by fitting the outline of the spool, which improves the measurement accuracy of the spool position. By analyzing the vibration characteristics of the valve core under different inlet and outlet pressures, spring stiffness, and other conditions, it is shown that the spatial range and impact degree of the valve core vibration are closely related to the operating conditions of the hydraulic system and the valve core structure. When the inlet pressure increases from 3.2 MPa to 4.4 MPa, the vibration of the valve core gradually intensifies, and the dispersion increases; when the precompression amount increases from 14 mm to 17 mm, the valve core vibration tends to be stable and the dispersion decreases. In addition, with the increase of the spring stiffness and the valve core half cone angle, the dispersion of the valve core vibration also shows a trend of decreasing firstly and then increasing, and its minimum values appear when the spring stiffness is 2 N/mm and the valve core half cone angle is 30°. In the projection of the spool vibration along the axial, front, and side directions, the waveform factor of the side radial vibration is larger than that of the front radial, while the waveform factor of the axial vibration is the smallest. The variation trend of the waveform factor is consistent with the variation trend of the dispersion. The dispersion of the valve core vibration is positively correlated with the waveform factor, and the waveform factor is the smallest when the valve core half cone angle is 30° and the spring stiffness is 2 N/mm. The research results can provide theoretical support for the structural design of the hydraulic valve with the poppet valve structure, thereby improving the stability of the hydraulic system and reducing the damage to the hydraulic valve caused by vibration.