Stenso - Hovedkatalog 2019

Guide Ring Guide rings have a rectangular cross-section and are chamfered at the corners to avoid excess edge pressures at groove corners. The chamfers also serve to simplify assembly. The standard design has a chamfered cut at the ring end. Guide rings can beused for every piston and rod diameter. The slit "m" is especially necessary for that function. Materials Overview AF-9600: Preformed slide ring from fabric cotton and phenolic resin reinforcement without auxilliary lubricant. Good shear characteristics, high compression and wear resistance. Meant for high loads in foodstuffs and pharmaceutical industry. AF-9610: Preformed slide ring from fabric cotton and phenolic resin reinforcement with graphite as additional lubricant. Good shear characteristics and resistance to galling, high compression and wear resistance. Meant for heavy duty hydraulics and pneumatics. AF-9210: Slide band from fine plastics fibre with additional lubricant. Very high com- pression resistance, high wear resistance and good shear characteristics. Meant for heavy duty hydraulics. AF-9200: Slide band from fine plastics fibre with PTFE lubricant. Very high compres- sion resistance, high wear resistance and good shear characteristics. Meant for heavy duty hydraulics. Material Data Type AF-9200 andAF-9210 Type AF-9600 andAF- 9610 Compress. strength, stat. N/mm² 345 250 Compress. strength, dyn. N/mm² 70 55 Temperature range °C -40 to +130 -50 to +145 Water uptake % < 0,1 < 1,2 Calculations Designing and sizing of wear ring for dynamic applications is dependent to a large ex- tent on the radial force and the associated deformation strength of the material, wear rings cut splitting and service temperature. The value of the dynamic compressi- ve strength is to be considered, taking the above factors into account. In practice is it important to include a factor of safety. Non metallic materials are preferred instead of metal bushes for use in wear rings to pistons and piston rods of hydraulic and pneu- matic cylinders. This is specially important for applications like mining, building and heavy machinery engineering where exceptionally high or inadequately defined radial forces come into play. In accordance with the above calculations, a choice can be made as: 1 slide ring for groove width of 15.0 mm. 2 slide rings for groove width of 9.7 mm. To cover as much of surface as possible, incorporation of two wear rings is to be recom- mended. Where: B = min. width of guide ring [mm] min F = max. radial load [N] R = permissible dynamic compression zul.dyn strength [N/mm²] S = safety factor D = nominal diameter (of rod/piston) [mm] n B min [mm] > .F S R . D zul. dyn. n Rod diameter D = 63 mm n max. radial load F = 40000 N R dyn. compr. strength = 70 N/mm² zul.dyn (material AF-9600) Safety factor S = 2 B min 18,1 > 40000 ·2 70 · 63 Example: ~ 201 PWR, RWR Guide Rings