Elaboration of a lubrication system for universal spindle hinges of rolling mills

The experience of running drives of most of heavy-duty rolling mills shows that the designs of universal spindles with blade hinges under conditions of increased alternating loads are most acceptable comparing with other spindles types. Open friction surfaces are the drawbacks of these types of spindles, which complicate the matter of continuous supply of lubrication. Perfected effective system of forced lubrication of rolling mill spindles hinges proposed. The facility for their lubrication has a bearing support of balancing design, spindle, in radial holes of which spring-loaded plungers are installed in a diametrically opposite order. Besides, the facility has suction valves and force valves installed in the spindle axial holes, connecting with the radial ones. A methodology proposed to select the eccentricity of the internal cylindrical surface of the bearing support of the spindle hinge, the axis of which is located eccentrically relative the spindle rotation axis. A calculating scheme and a mathematical model of the process of lubrication supply into joints of rolling mill spindle hinge elaborated. A differential equation of lubrication motion in the conical slot of the hinge between a blade and insertions drawn up. Parameters of hydrodynamic motion of lubrication in the conical slot established. Modes of the lubrication motion in the conical slot between roller blade and hinge insertion determined. Based on experience of operation of friction couple bronze-steel, a lubrication for rolling mills universal spindles proposed. To improve the operation characteristics of hinges based on the friction couple bronze-steel, a thick lubrication having antifriction properties namely based on oils with additives ИП-10, КП-10 and ДФ-11 proposed. Dependence of pressure distribution along the length of the hinge conical slot presented for various lubrications of low viscosity (ИП-10 + ДФ-11) and high viscosity (КП-10 + ДФ-11). The quality effect of the speed of roller blade movable wall on distribution of speeds of lubrication layer motion over the height of the hinge conical slot for comparatively low and comparatively high boundary speeds demonstrated.

Toolpath Planning and Simulation for Cutting Test of Non-Orthogonal Five-Axis Machine Tool

Owing to NAS 979 describes a cutting test for five-axis machine center with a universal spindle, several conditions for C-type machine tool have not been defined yet. This paper proposes a cutting test for a non-orthogonal swivel head and a rotary table type five-axis machine tool (C type) to evaluate its performance. The workpiece consists of 10 machining features. These features include the multi-axis simultaneous machining patterns and the positioning machining patterns. The flat end mill cutters are applied in each machining feature. Cutter location data for the test piece was generated using a commercial CAD/CAM system (UG) and converted to five-axis NC code using a postprocessor created in UG Post Builder. This UG postprocessor is verified through the developed postprocessor utilizing the modified D-H notation. It is also verified using VERICUT® solid cutting simulation software demonstrated the veracity of the generated five-axis NC code. The machining test is applicable for a variety of five-axis machine tool configurations.

Finite Element Analysis of the Influence of Balance Mode on Rolling Mill Universal Spindle Strength

For the problem of balance bearing of universal spindle in rolling mill being prone to damage, the paper established mechanical model and finite element model of universal spindle. The paper has analyzed that the shear and bending moment in the middle of the shaft is the largest. The fillet near shoulder of balance bearing of the spindle is dangerous part. In order to reduce principal stress of universal spindle caused by moment, the paper improved balance mode of the spindle. The equilibrant was applied from in one place of shaft to put in two places. After optimizing, equivalent stress of the spindle is slight smaller than before under the same loading condition, which illustrates that the strength of the spindle is appropriately improved. Although the effect is not obvious, this has played a guiding role for the optimization of balance mode of universal spindle.

Research on Spindle Bearing Pre-Tightening Based on Spacer Sleeve Adjustment

Machine spindle pre-tightening force is closely related to machining precision. Universal spindle is generally pre-tightened through spacer sleeve adjustment. The calculation method about bearing pre-tightening force is put forward through analyzing and computing the main factors of bearing pre-tightening force, and the machine spindle bearing pre-tightening methods based on pre-tightening force are described in detail. This method is used for installation and maintenance of machine spindle, and it is proved to achieve the accuracy recovery of high-revolution, high-precision machine spindle.