Providing Cavitation-Free Operation of Hydraulic Systems under Passing Load in Hydraulic Actuator

Abstract

The problems of braking and positioning of hydraulic actuators are an integral part of output speed control in hydro-pneumatic actuators. This article is focused on a hydraulic braking of driven elements of machines and mechanisms which is carried out by devices known as brake valves (counterbalance, load control, over-centre valves). Brake valves are used to exclude overrunning speed under passing loads when the external load direction coincides with the direction of movement (rotation) of the hydraulic actuator. They provide a constant pressure in pressure line and prevent cavitation. In this article the design and operation of brake valves are analyzed. The need for brake valves in hydraulic machines with hydraulic actuators under a passing load is proved. As a result of theoretical research a mathematical model of dynamics of hydraulic actuator with a brake valve has been developed. This model unlike others takes into account the design of main and control spools of the brake valve. The problem of logging-running unit braking is solved by the use of the hydraulic brake valve as a part of hydraulic logging system.

Experimental research characteristics of counterbalance valve for hydraulic drive control system of mobile machine

“…Qualitative process of executive device control, energy losses decrease and operating fluid overheating is achieved. However, the hydraulic drive control system, based on CBV does not recycle energy [8,15,16,[20][21][22][23].…”

“…Installation of CBV on the winch enables to avoid problems dealing with emergence of cavitation processes during its braking [8]. In particular, circuit, mathematical model and experimental stand for studying CBV operation in the system of the winch hydraulic drive control is developed.…”