Unified Method for Evaluating the Strength Properties of the Bottom Parts of High-Pressure Hydraulic Cylinders

It is established that the bottom parts of hydraulic cylinders are bearing elements, in which the control valves are built-in, as a result of which their design is significantly complicated due to the need for special seating surfaces and additional holes for high-pressure fluid supply and connection of hydraulic control lines. The main factors that determine the design and parameters of highpressure hydraulic cylinders bodies are considered. The strength properties of the bottom parts of high-pressure hydraulic cylinders, in which the control valves are built-in, are evaluated. The bottom parts of hydraulic cylinders have been studied using the finite element method. According to the results of the stress-strain analysis of the hydraulic cylinder bottom part, it has been found that making the bevel radius smaller than the allowable design value causes the appearance of the pronounced stress concentration zones in it, and deepening of the bevel into the bottom part more than the value fixed by the study leads to appearance of the additional radial forces, which predetermine plastic deformations and promote the development of fatigue cracks. A comparative analysis of different schemes of making fillets in the bottom parts of hydraulic cylinders has been made. A number of curves have been made by the results of the analytical calculations. These curves allow to project a high-pressure hydraulic cylinder body, ensuring a rational ratio of the relevant design parameters of the bottom part and taking into account a notch for the control valve and high-pressure liquid supply and a necessary safety margin under given operating conditions in accordance with a particular value of the bottom slackening coefficient. The method of designing the bottom part of hydraulic cylinders with built-in valve for technological equipment with hydraulic drive, which is used in different areas of mechanical engineering, is unified.