Abstract: Based on the introduction of the structure, the operating principle and the pressure-flow characteristics of the PM flow controller, the bearing capacity, the oil-film stiffness and the dynamic transfer function of the rectangular contra-positive oil pocket with PM flow controller are derived. Taking a pair of contra-positive oil pockets of a machine tool for an example, the mutual relationship among the flow ratio cr, the initial flow q0, the pump pressure ps, and the influence of three parameters on the bearing capacity, the static stiffness and the dynamic characteristics are analyzed. The research indicates that, if the initial flow q0 and the pump pressure ps are determined, the static stiffness gets larger gradually with the increase of cr. There is a peak value of the static stiffness when cr= 6.2, and it is detrimental to the normal operation of the hydrostatic slide. The reasonable value scope of cr is 1.2～5.2. Meanwhile, the larger the q0 , the smaller the pp, and the larger the static stiffness of the oil pocket. Based on the transfer function expression of the oil film thickness, when the volume of the sensitive oil circuit Vo=500 cm3, the influence of the different flow ratio cr, the initial flow q0, the pump pressure ps on oil film dynamic characteristics in time and frequency domain under the step load is considered. The research has shown that in time domain cr, q0 and pp affect the overshoot of the oil film thickness. The overshoot increases obviously with the increase of cr, q0 and the decrease of pp. To improve the bearing stability of the oil film and decrease the overshoot during the transient process, it is best to decrease cr, q0 and increase pp. In frequency domain, the peak frequency of the amplitude-frequency characteristic curve is the nature frequency of the oil vibration. With the increase of cr, q0 and the decrease of pp, the amplitude and the nature frequency get larger, and the frequency scope of the instability zone becomes wider. When the frequency is very high, the influence of cr, q0 and pp on the amplitude is small. The research on the design of the hydrostatic slide based on the PM flow controller has certain reference value.

Key words: Frequency characteristics, Hydrostatic slide, PM flow controller, Static stiffness, Transient characteristics