Proof of the functionality of a flat sliding valve with ceramic components for the hydraulics

 

Motivation

For the control of fluid flows, traditional piston sliding valves with metallic cylindrical spools are primarily used in hydraulic systems. However, this kind of valve has typical corrosion and wear problems at the spool edges, which lead to the rounding of edges. Moreover, the principal gap between the spool and sleeve leads to an annular gap with a height of about 3 to 10 microns. The edge rounding and the annular gap result in an unavoidable leakage between the chambers when a pressure differential is applied. This causes a loss of performance and a reduction of efficiency of valves.

Compared to metals, high-performance ceramics have significantly higher corrosion- and wear resistance. Additionally, the high possible parallelism of the ceramic plates allows almost closed gaps. Therefore, the edge rounding and the annular gap of the piston sliding valves can be significantly reduced when the flat sliding valve with high-performance ceramic plates are applied.

Goals

• Selection of the most suitable ceramic pair for the application of flat sliding valves
• Reduction of fracture probability by optimizing the geometry of ceramic plates

Content

• Characterization of different high-performance ceramics
• Investigation on the friction performance of ceramic pairings
• Determination of flexural strength and Weibull parameters via bending tests
• Prediction of short-term fracture probability of ceramic components

Funding

VDMA - AiF