Mill Spindles
20Pages

Mill Spindles Carburized and Nitrided Designs Crowned and Barrelled Teeth with Tooth-Tip Piloting High Power Density Roll End Piloting Tight Fitting Spline Connections With Long Life Custom Compound Tooth Curvature Superior Technology www.renold.com

Capabilities New CNC machinery New CNC machinery Cell manufacturing approach Gear shaping machine New electro discharge wire machine CNC hobbing machine 3

Spindle Parts and Assembly Type 1 roll end ring gear Spindle in paint booth Advanced load-sharing tooth design Finished parts staged for assembly Finished hot strip mill spindles Type 3 roll end adaptor 4

Spindle Parts and Assembly Main drive for large reversing mill Large gearbox ex halves Large telescopic spindle Finished assemblies head to overseas packager Finished hot strip mill spindles Various parts ready for assembly Roughing spindle ready for shipment 5

Spindle Design Types Design and construction characteristics balance the cost of the initial investment versus the cost to maintain the spindle over years of services. Renold offers basic designs. Type 1 1 Type 1 is normally used in smaller mills or in mills with restrictions on spindle diameters such as small minimum work roll diameter or pinion shaft center dimension. It features a high torque capacity with maximized pitch diameter. This spindle is the most economical in initial investment but the most costly to maintain because gear element replacement involves replacement of the entire...

Spindle Design Types Continued Type 2 1 Type 2 provides the maximum pitch diameter and therefore the highest torque capacity like the Type 1 but uses a replaceable gear element to reduce maintenance costs. 2 3 4 5 1 2 Sleeve Ring Gear 3 Hub Gear 4 Center Shaft 5 7 Pinion End Adaptor Roll End Adaptor

Spindle Design Types Continued 1 Type 3 The Type 3 offers the least possible cost in maintenance, but this economy in gear element replacement comes at the expense of torque capacity because the pitch diameter must be reduced relative to the outside diameter. 2 Highest initial cost for a given torque capacity is offset by economical maintenance costs in operation. 3 4 5 1 2 Ring Gear Insert 3 Hub Gear 4 Center Shaft 5 8 Pinion End Adaptor Roll End Adaptor

Spindle Design Types Continued Type 4 Type 4 spindle is a combination of Type 1 and Type 3 spindle designs which is used as a compromise of initial cost vs. cost to maintain when minimum roll diameters are much smaller than the pinion shaft center dimension. 1 2 3 4 5 1 2 Ring Gear Insert 3 Hub Gear 4 Center Shaft 5 9 Pinion End Adaptor Roll End Adaptor

Continuous Circulating Oil Lubrication In order to address the inadequacies of grease lubrication, Renold has developed an oil lubricated spindle design for use in all types of mills including Hot Strip Roughing and Finishing applications. All types of spindles create heat through sliding contact under heavy compressive stress at the tooth anks of the contacting teeth. Conventional grease lubricated spindles rely on this heat to be emitted from the OD of the spindle. If the heat generation rate exceeds the rate at which the heat can be emitted, then the temperature will rise to unsafe...

Continuous Circulating Oil Lubrication Continued Stationary housing Split oil transfer bearing 4 1 3 2 5 The Renold Continuous Circulating Oil Lubrication System provides a vehicle to remove this destructive heat. Oil is pumped onto the rotating spindle components through a transfer bearing, where it passes This process also ushes away any wear debris that occurs at the tooth anks, instead of allowing it to remain at the gear mesh to act as lapping compound, as is the case with grease lubrication. 1 radially inward, 2 through the center of the shaft, This Oil Lubrication System has been...

Spindle Designs and Features These examples show some of the features of Renold Ajax Spindles that are currently in operation. Spherical Seal Single Lip Seal Rising Lip Seal Double Lip Seal Rising O-Ring Various Seal Options available on Renold Ajax Spindles Vertical Type 3 telescopic spindle for top driven bar mill 12

Spindle Designs and Features Continued Heavy duty motor coupling Consult Renold Ajax Engineering personnel with your application, and let us customize a spindle to meet your exact needs. Type 3 hot strip reversing rougher spindle with overload release arrangement 13

Spindle Designs and Features Continued Type 3 telescopic spindle with spherical seals for single stand reversing (Steckel) mill with roll shifting Type 3 telescopic spindle for hot strip nishing stands with roll shifting Maximized tooth contact at load angle Single Curvature Single Compound Curvature Renold uses a compound curvature on the tooth ank to maximize the working area of the tooth, reduce Hertzian contact stress and vastly extend wear life. 14

Spindle Designs and Features Continued Renold also uses a piloting system to reduce the action in the roll end bore without interfering with the roll change process. This system helps to reduce bore wear, reduce vibration and chatter, and improve product quality from the mill. 15

Materials and Heat Treatment carrying teeth. Correcting distortion by lapping or grinding decreases the case depth. As with induction hardening 4140, carburizing’s low tempering temperature of 350o F to 400o F can lead to soft spots and rapid wear. In selecting gear spindle material, mill operating conditions, desired spindle service life and cost must be taken into consideration. Early gear spindles were made of medium carbon steel (AISI 1045), normalized and induction hardened for surface wear. This material and heat treatment is still used today, but the search for better performance and...

Preliminary Spindle Coupling Selection Guide To guide the designer and user in preliminary selec- tion of mill spindle couplings, the following approach is recommended. Final selection is best handled by Renold application engineers. ■ Compute normal torque. ■ Select proper service factor. ■ Determine load / no load misalignment factor from Graph A. (The no load angle is critical - hold ■ Calculate design torque. ■ From Graph B or C, determine spindle diameter. ■ Cross check size with nominal bore and envelope limitations. ■ Send preliminary selection and required data to Renold for final...