Модульные инструментальные системы линейки KM4X Kennametal 2017 - страница 118

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Technical Manual Spindle Design 5.2 Spring Pack Design Spring selection should follow the basic guidelines below: • Use the largest possible diameter to increase fatigue life and reduce spring pack length. • For a given disc spring diameter and thickness, the longer the stack, the longer the life. • Parallel stacking (spring sets in series) allows for shorter spring packs and higher spring force; however, a friction factor is introduced between the springs. Technical Manual • Maximum number of springs stacked in parallel should be three, unless specified otherwise. • Larger number of sets reduces spring pack force at tool release. • Spring pack force at the “clamped without tool” position should be greater than or equal to the minimum clamping force divided by the mechanical advantage. • Spring pack force at the clamped position should be greater than or equal to the nominal clamping force divided by the mechanical advantage. This is a representation of three sets of springs that have two springs in parallel. 5.3 Spring Pack Design Example for KM4X100 Spring Force 20kN 18kN Displacement -1,2mm 0mm 8mm 11,8mm Tool Release Spindle Clamping End of Stroke Face Position (Minimum Held) Design A: Preferred design. Less variation in clamping force and lower force at tool release position; 20kN at clamping position and more than 18kN at the end of stroke (minimum held). Longer spring life than designs B, C, and E. Design B: Good solution. 20kN at clamping position and 18kN at end of stroke. Design C: Higher resultant spring constant. Designed to provide 18kN at the end of the stroke (required), providing higher than nominal clamping force and higher force at tool release. Lower spring life, but also good design. Design D: Designed to provide 18kN at the end of the stroke (required), providing lower than nominal clamping force at clamping position and low force at tool release. Highest spring fatigue life. Acceptable solution when clamping force is not a major concern. Longest spring life. Design E: Nominal clamping force achieved at clamping position, but resultant spring constant (stiffness) is excessive and minimum force at the end of the stroke cannot be achieved. Low spring life and high spring force at tool release position. This design must be avoided. C18 kennametal.com L V i KMT KMT_KM4X_Catalog_C018_C019_EN.indd 18 KM4X C l C018 C019 EN S b 1 2016 12 53 PM 9/1/16 2:03 PM