Adjustable Viscous Spindle Damper for Wide-Range Vibration Control
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Solution Overview
Problem
Existing vibration damping systems for machine tool spindles are limited in their ability to adapt to varying excitation frequencies and often result in inefficient damping due to geometric imperfections, leading to increased wear and reduced machining quality.
Innovation Solution
A vibration damping device featuring a housing with an annular damper mass and a gap filled with viscous liquid, where the gap width is adjustable, allowing for adaptable damping behavior through varying friction generated by shear forces, and supported by spring elements for resilient movement in multiple directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed damping system is used, then the damping effect is simple and reliable, but it can only be designed for a single excitation frequency and cannot adapt to varying operational conditions
Solution Approach 1:
The patent implements adjustability by allowing the damping mass to be repositioned axially along the shaft, enabling the system to adapt to different excitation frequencies. The damping mass can be moved to different positions where it interacts with damping fluid in gaps of varying widths, thereby dynamically adjusting the damping characteristics to match different operational conditions and frequency ranges.
Solution Approach 2:
The patent changes the parameter of gap width between the damping mass and housing to adjust damping characteristics. By varying the gap width (through axial positioning of the damping mass), the system modifies the amount of damping fluid interaction, thereby changing the damping coefficient to suit different excitation frequencies without requiring a completely different damping system.
2Reliability
If the damping mass is tightly coupled to the housing, then the structural stability is improved, but the damping effect is reduced because the damping mass cannot move relative to the housing
Solution Approach 1:
The patent introduces damping fluid as an intermediary substance between the damping mass and the housing. The damping fluid fills the gap between these components and provides the necessary coupling: it allows the damping mass to move relative to the housing while simultaneously transmitting damping forces. This intermediary enables both relative motion (for damping effect) and structural connection (for stability).
Solution Approach 2:
The patent employs hydraulic damping by using a viscous fluid (damping fluid) to provide the damping effect. The damping fluid is contained in the gap between the damping mass and housing, and its viscosity creates resistance to the relative motion of the damping mass, thereby dissipating vibration energy while maintaining structural connection.
3Adaptability or versatility
If the gap width between the damping mass and housing is large, then the adjustability is improved, but the damping effect is reduced due to decreased friction from the damping fluid
Solution Approach 1:
The patent makes the gap width a dynamic parameter that can be adjusted based on operational requirements. By allowing axial movement of the damping mass along the shaft, the system can dynamically change the gap width between the damping mass and housing, thereby adjusting the damping effect in real-time to match varying excitation frequencies and operational conditions.
Solution Approach 2:
The patent uses parameter changes by varying the gap width (through positioning adjustments) to optimize damping performance. The gap width serves as a controllable parameter that directly influences the damping coefficient: smaller gaps provide stronger damping through increased fluid interaction, while larger gaps reduce damping. This parameter adjustment enables adaptation to different operational scenarios.
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
The device effectively dampens vibrations across a wide frequency range by adjusting the gap width and viscosity of the damping fluid, providing a flexible and efficient solution to the limitations of existing systems.
Implementation Method 1
a gap (21) is provided between a circumferential surface of the damper mass (16) and an inner surface of the housing (2), which is filled with a viscous damper fluid
Implementation Method 2
shear forces act on the fluid in the gap, which in turn generate internal friction within the viscous fluid, thus decelerating the movement of the damping mass
Implementation Method 3
at least one spring element (22, 23) by which the damping mass (16) is held resiliently and elastically on the housing (2) with respect to the longitudinal axis of the device (1) at least in the circumferential direction of the damping mass
Implementation Method 4
The friction generated in the fluid within the gap changes proportionally to the clear width of the gap. With larger gap widths, friction and consequently the braking effect are lower than with narrow gap widths
Data Source
Figure 1
AI summary
The invention provides a device for damping vibrations of a spindle of a machine tool rotating about a rotary axis, which has a central longitudinal axis (L) aligned coaxially to the rotary axis of the spindle in use, and a housing (2) which is provided for rotationally fixed coupling to the spindle and delimits a housing space (9) which is designed as an annular space aligned coaxially to the central longitudinal axis (L) and revolves around the central longitudinal axis (L), an annular damping mass (16) which is movably arranged in the housing space (9) relative to the central longitudinal axis (L) and is aligned coaxially to the central longitudinal axis (L) in the rest state, and comprises at least one spring element (22, 23) by means of which the damping mass (16) is held resiliently and elastically on the housing (2) with respect to the central longitudinal axis (L) of the device (1) at least in the circumferential direction of the damping mass (16).In such a device, by providing a gap (21) between a circumferential surface (14) of the damping mass (16) and an inner surface (20) of the housing (2), which is filled with a viscous damping fluid, and by making the clear width (WL) of the gap (21) filled with the viscous fluid adjustable, the damping effect can be easily adapted to the respective requirements.