To drive the rigid tube sleeve or the biaxial flexible roller with different diameters to bend the hollow thin-walled tube sleeve with larger outer diameter
on the rigid roller is equivalent to increasing the diameter of the rigid roller and rolling the thin-walled tube of the thin-walled piece with different diameters
tightly connected to the rigid roller without deformation.
The outer diameter of thin-walled tubes is usually in series.Or provide rigid rollers of various diameters, such as two shafts made in Russia, and provide parametric models
of the series diameter of rigid rollers.
The aim is to transform the sensitive free roll bending area into several coupling roll bending and several continuous roll bending controllable areas,
which are suitable for single curvature parts and high precision roll bending occasions
The flexible pad made of high elastic material is first rolled into a bending piece.
When the flat sheet is put into the roll, the flexible pad is added for rolling and bending.
Since the pad only experiences elastic deformation, the shape and size of the pad remain the same before and after processing, so the pad can be reused.
The bending of the roll with the flexible cushion is basically equivalent to increasing the diameter of the rigid roll, and thin-walled parts with different radii can be
manufactured without changing the rigid roll.
3) Variable diameter biaxial flexible roll bending, whether rigid pipe, rigid roller of various diameters or flexible cushion, is characterized by the fact that the pressure
in the rigid roller and flexible roller is greater than the optimal pressure in the preferred pressure is the pressure in the rigid roller and flexible roller, which can only make
the thin plate adhere to the rigid roller before springback.
The flexible roll bending technique of reducing diameter is to roll thin-wall parts with different diameters by controlling the pressure of rigid and flexible rolls without achieving the
optimal pressure.
Based on the external force of the workpiece and the classical formula of rebound, as well as the calculation formula of radial stress, circumferential stress and bending moment
of the plate during rolling and bending deformation, the relation expressions between the radius of the bounce-back workpiece and the pressure amount, the material parameters of
the workpiece, the radius of the rigid and flexible roller and the material parameters can be established.
Theoretical model error is bigger, was 15%, the error is small, 2.6% elastic layer in the process of roll bending stress in order to analysis, puts forward the concept of lower
modulus of elasticity to define polyurethane rubber in the process of the flexible roll bending elastic modulus, elastic modulus changes with the forming process, and deduce the
formula of lower modulus of elasticity of polyurethane rubber, the formula can accurately describe the polyurethane rubber roller bend forming process in the state of strain distribution.
Flexible roll bending technology with variable diameter still needs to be studied in detail.At present, the precision is not high, elliptical parts in the same amount of rolling.
