D170 Cu 60–66% Al 5,0–7,5% Fe 2,0–4,0% Mn 2,5–5,0% Zn 17,5–31,5% 8,2 750-800 180–210 450–550 5–8 105–115 0,04–0,15 45–55 1,6–2,0 × 10-5 7–8 ±150 25–30 5000 80 30 10000 OILLESS GUIDE ELEMENTS DESCRIPTION Low-maintenance sliding elements are used in the tool & die building as well as the machine building industries, for both linear and rotary motion applications. The material for these sliding elements is made of a base material (see chart), and an overlapping network of solid lubricant deposits. These deposits are embedded in a uniform geometric pattern in order to achieve the optimum lubrication coverage in the direction of the movement. The allowable directional movements can be found on the catalogue pages, and are marked with symbols. The optimum sliding conditions are achieved when the sliding elements are combined with a hardened and ground opposing surface, which are a minimum of 100 HB harder than the base material. A surface roughness of approx. Rz6.3 is optimal. Suitable product combinations of guide pillars and low-maintenance guide bushings can be found in the selection matrix at the beginning of chapter D. It is recommended to lightly lubricate the sliding surfaces of the low-maintenance sliding elements with lithium saponified grease, before usage. The solid lubricant will only be distributed from the pockets in the sliding zone during operation. In general, 25-35 % of the sliding surface is embedded with solid lubricant deposits, but deviations are possible due to the shape and size of a particular component. The size and arrangement of the solid lubricant deposits may also vary within the various products and sizes. A repair of the slide elements is possible. The sliding surface is usually re-ground. Advantages of oilless guide elements – Low-maintenance, with optimum conditions maintenance-free – low friction – good emergency sliding properties – „Stick - Slip“ effects are eliminted – extremely wide temperature resistance – hot and cold – damping properties in presence of vibration Characteristics for base material chemical composition specific density [kg/dm3] Tensile strength Rm [N/mm2] Brinell hardness HB 10 Yield point Rp 0.2 [N/mm2] Elongation to fracture A5 [%] Elasticity module [kN/mm2] Co-efficient of friction Thermal conductivity [W/(m × K)] Heat expansion coefficient [K-1] Electric conductance [m/(Ω × mm2)] alt. flexural strength [N/mm2] ratio sliding surface to lubricant deposits (%) Special version Rebuilds and other specifications and designs upon request. Surface pressure, temperature, speed and lubrication PV value The permissible bearing load is determined from the pressure and the PV value, which defines the bearing wear. The PV value is the product of surface pressure (P) and running velocity (V). Please keep in mind, that the maximum allowed speed and surface pressing can not be reached at the same time (see PV diagram) Calculation for the existing bushing load: PV = P x V (N/cm2 x m/min) P = F/A (N/cm2) F = Loading force (N) A = Projection surface of the guide bushing/sliding surface [cm2] V = Sliding speed [m/min] Sliding speed with lifting motion: V = 2 × H × nf/1000 [m/min] H = Stroke [mm] nf = Number of strokes [H/min] max. surface pressing [N/cm2] Temperature [C°] Speed [m/min.] PV value [N/cm2 × m/min] Lubrication Initial PV-diagramm * Example: At a surface pressing of N/cm² is, because of the maximum PV-value of N/cm² x m/min. the maximum allowed speed m/min. Surface pressure [N/cm²] Speed [m/min.] *
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