Adjustable Ram Damper Assembly for Vertical Lathe Vibration
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Solution Overview
Problem
Vertical lathes with narrow rams at long extensions suffer from inadequate dynamic stiffness, particularly at specific frequencies related to structural natural frequencies, limiting their cutting capability.
Innovation Solution
An adjustable damping arrangement using springs to suspend a damper mass within the ram, combined with compressible rubber rings that can be selectively compressed to adjust the dynamic stiffness by tuning the damper mass to match the resonant frequency of the ram, thereby enhancing damping and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the ram extension is increased to reach tall parts, then the reach is improved, but the dynamic stiffness deteriorates
Solution Approach 1:
The damper mass is suspended by springs that allow dynamic movement, enabling the system to adapt its stiffness characteristics. The mass can move relative to the ram body, creating a dynamic response that counteracts vibrations at different extension positions, thus maintaining stiffness despite increased length.
Solution Approach 2:
The dynamic stiffness of the damper can be adjusted by changing the pre-compression of the rubber rings. By modifying this parameter, the damper can be tuned to provide optimal stiffness compensation at different ram extension positions, allowing the system to maintain adequate stiffness even when the ram is extended to reach tall parts.
2Strength
If damping elements are added to increase damping, then the dynamic stiffness is improved, but the device complexity increases
Solution Approach 1:
The damper assembly integrates multiple functions into a single compact unit: the damper mass provides inertial damping, the springs provide suspension and frequency tuning, and the rubber rings provide adjustable stiffness. This merging of elements into one integrated assembly adds damping capability without proportionally increasing overall structural complexity.
Solution Approach 2:
The damper mass is positioned inside the hollow ram structure, nesting the damping mechanism within the existing ram geometry. This nested arrangement allows the addition of damping elements without significantly increasing the external dimensions or overall structural complexity of the ram assembly.
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 solution increases the cutting capacity of vertical lathes by effectively absorbing vibrational energy, improving dynamic stiffness and reducing the minimum stiffness to match or exceed other frequencies, thus enhancing the machine's operational performance.
Implementation Method 1
springs to suspend a damper mass
Implementation Method 2
A spring-mass-damper may be tuned to a particular frequency
Implementation Method 3
damping rubber rings that can be selectively compressed
Implementation Method 4
Greater damping results in higher stiffness
Implementation Method 5
damping which may be defined as the ability to absorb or neutralize vibrating energy
Implementation Method 6
A spring-mass-damper may be tuned to a particular frequency for operation of the ram at the greatest extension, the lowest stiffness condition for the ram
Data Source
AI summary
A damper assembly for use with a non-rotating tool holder includes a hollow ram for supporting a non-rotating tool and a damper assembly mounted in the hollow ram for absorbing vibrations of the ram. The damper assembly includes a front plate and a rear plate, an upper tie rod and a lower tie rod extending between the front plate and the rear plate, and a damper mass mounted between the front plate and the rear plate. Ring dampers are mounted between the damper mass and the front and rear plates, and suspension springs are mounted between the upper tie rod and the lower tie rod. The suspension springs carry the weight of the damper mass so that the ring dampers do not have to carry the weight of the damper mass, and the damper mass is free to respond to vibrations in the ram.