Stand for Testing Hydraulic Actuators with Modified Working Surfaces

Increasing production costs require the search for new cheaper or more durable solutions for hydraulic components, such as actuators. Direction of the development of actuator constructions is to apply new methods of modifying surfaces of working elements, for example, pistons and piston rods. Operation of actuators under high pressure and variable temperatures, additionally in a hydraulic oil environment, requires special properties of the surfaces, in particular, low friction coefficients, high hardness, and resistance to abrasion, corrosion, or aggressive environments. This paper presents a test stand for actuators with various working surfaces. The test stand can be used for long-term tests (fatigue tests) performed on four actuators simultaneously, as well as for testing selected parameters, such as mechanical-hydraulic efficiency. One of the actuators is a reference actuator made of typical material and standard surface modification, while the others are manufactured using modern surface modification methods, such as nitriding, nitrosulphurization, or application of a DLC carbon coating enriched with tungsten carbide particles. The design of the workstations makes it possible to set different load levels on all cylinders simultaneously, as well as different operating speeds. All important parameters of the working cycles and the number of cycles performed are measured. The article presents examples of measurement cycles.