Roll Neck Bushing Mounting for Axial Movement in Roll Stands
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Solution Overview
Problem
Existing roll stand designs face issues with wear and damage due to axial stresses on neck bushings, requiring large fastening units, long roll necks, and time-consuming mounting/dismounting processes, especially in hydrodynamic plain bearings where radial and axial deformation is necessary.
Innovation Solution
The neck bushing is mounted in an axially movable manner between two abutments on the cylindrical roll neck, allowing for axial displacement and deformation, eliminating the need for traditional fastening units and enabling radial deformation without mechanical overloading, using an axial plain bearing with a lubricant supply system for reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the neck bushing is fixed axially with fastening units, then the neck bushing is securely held on the roll neck, but wear and damage occur due to axial stresses and mechanical overloading
Solution Approach 1:
The neck bushing is designed to be axially movable between two abutments instead of being fixed, allowing it to dynamically adjust its position during operation. This dynamic configuration enables the neck bushing to accommodate axial displacement and deformation without mechanical overloading, preventing wear and damage while maintaining secure holding through the abutment constraints.
2Reliability
If traditional fastening units are used to hold the neck bushing, then the neck bushing is secured during rolling operation, but the roll stand requires larger dimensions and more components
Solution Approach 1:
The invention extracts and eliminates the traditional fastening units (such as pressure shoulder rings, feather keys, and pull-on devices) from the neck bushing assembly. Instead, the neck bushing is retained through its functional interaction with the two abutments, one on the roll neck and one on the axial bearing, thereby simplifying the overall structure while maintaining securing during operation.
Solution Approach 2:
The axial bearing serves a dual function: it provides radial support for the roll and simultaneously acts as the second abutment to axially retain the neck bushing. This multi-functionality eliminates the need for separate fastening components and reduces device complexity.
3Strength
If the neck bushing is shrunk-fit on the roll neck, then the neck bushing is firmly attached, but radial deformation is prevented which is essential for hydrodynamic bearing function
Solution Approach 1:
The retention mechanism is segmented into two independent abutments positioned at different locations (one on the roll neck and one on the axial bearing). This segmentation allows the neck bushing to be firmly attached axially while leaving its radial surface free for deformation, as the abutments constrain only axial movement without interfering with radial expansion.
4Reliability
If conical roll necks with pressure shoulder rings are used, then the neck bushing is axially positioned, but large fastening units and long roll necks are required
Solution Approach 1:
The axial bearing acts as an intermediary component that provides the second abutment for axial positioning of the neck bushing. By introducing this intermediary element, the roll neck itself can be shorter, as the axial bearing assumes part of the retention function, eliminating the need for long roll necks with integrated pressure shoulder rings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces wear and damage by allowing natural displacement of the neck bushing, eliminates the need for extensive fastening components, and ensures effective lubrication for reduced mechanical stress during rolling operations.
Implementation Method 1
The neck bushings together with bearing bushings in the chocks typically form a radially acting plain bearing. In such hydrodynamic plain bearings, especially oil film bearings, however, the neck bushing moves and deforms under loading not only in the radial direction, but also in the axial direction.
Implementation Method 2
an axial plain bearing with a lubricant supply system for reduced wear
Data Source
AI summary
A roll stand for the rolling of rolling stock, especially metal products. The roll stand includes at least two chocks for mounting at least one roll, the roll being rotatably mounted in the chocks by its two cylindrical roll necks. A cylindrical neck bushing is arranged on the roll neck with radial play. A rotationally fixed annual axial bearing is axially offset from the neck bushing. The bearing arrangement for the roll necks in the chocks is formed as a plain bearing, preferably a hydrodynamic oil film bearing. When subjected to a load in a rolling process, the neck bushing moves and deforms not only in the radial direction, but also in the axial direction.