关键词: 液压元件, 二维活塞, 微间隙, 剪切空化

Abstract:  Two-dimensional hydraulic components could benefit from the surface sealing and circumferential distribution of two-dimensional pistons, but they might face cavitation due to oil shear in the gap between the piston and cylinder body. In order to investigate the one-dimensional motions of the oil in the gap, a shear rheology device with a rotating outer cylinder was established to carry out visual studies of shearing flow, including the influences from various rotating speeds, fluid pressures, air ratios in the space above the shearing fluid field, inner cylinder outer wall surface with chute structure and micro-gap thickness. The experimental results demonstrate that the increase of flow field pressure linearly leads to larger critical shear stress， the more air there is in the space above the shearing fluid field, the stronger the effect of preventing shear cavitation， the two-dimensional pistons flow distribution groove structure will reduce the shear torque of the oil on the one hand, and change the pure shear flow field on the other hand, thus inhibiting the occurrence of shear cavitation， the decrease of gaps will decline critical shear stress, which makes the generation of the shearing cavitation ease.

Key words:  , hydraulic component, 2D piston, micro-gap, shear cavitation