Radial Rotor Damping Device for Compact Vibration Attenuation
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Solution Overview
Problem
Existing damping devices increase in size to enhance damping force, limiting their applicability due to the proportional relationship between rotor surface area and damping force, which restricts their effectiveness in attenuating vibrational energy between structural bodies.
Innovation Solution
A damping device with a cylindrical rotor member that covers the fixed cylinder, increasing its inertia moment and allowing for a larger mass distribution, synergistically combining the viscous fluid's damping effect with the rotor's inertia to effectively attenuate vibrational energy without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the axial length of the rotor is increased to enhance damping force, then the damping force is improved, but the entire length of the damping device is increased
Solution Approach 1:
The rotor is repositioned from an internal configuration (inside the housing member) to an external configuration (outside the housing member), utilizing the radial dimension instead of the axial dimension. This dimensional change allows the rotor surface area to be increased without extending the axial length of the damping device, thereby resolving the contradiction between enhancing damping force and maintaining compact size.
Solution Approach 2:
Instead of increasing the rotor length axially to increase surface area, the invention inverts the approach by increasing the rotor surface area through radial extension. The rotor is configured to rotate about the shaft member with its surface facing the housing member's inner peripheral surface, creating a containing chamber for viscous fluid in a radial rather than axial configuration.
2Force
If the rotor surface area is increased to enhance damping force, then the damping capability is improved, but the device size is increased
Solution Approach 1:
The invention transitions from axial dimensionality to radial dimensionality for rotor surface area expansion. The rotor extends radially outward from the shaft member, with its outer surface forming the containing chamber wall for viscous fluid. This radial configuration increases the effective surface area for damping without proportionally increasing the overall device volume, as the rotor operates within the existing radial envelope of the housing member.
3Loss of energy
If a longer rotor is used to increase damping force, then the energy attenuation is improved, but the stroke amount requirement increases
Solution Approach 1:
The invention inverts the conventional approach by not extending the rotor axially but rather utilizing radial extension to increase surface area. The rotor surface area is increased by expanding radially outward to form the containing chamber, while the axial stroke amount remains determined by the nut member's travel along the shaft member's thread groove, decoupling damping force enhancement from stroke length requirements.
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 solution effectively reduces vibration amplitude by converting vibrational energy into rotational energy, which is then attenuated by the viscous fluid, achieving enhanced damping capabilities in a compact form.
Implementation Method 1
a shear friction force in proportion to a rotational angular speed of the rotor is applied to the viscous fluid in the accommodation chamber. As a result, heat is generated in the viscous fluid. In other words, in this damping device, vibrational energy between the structural bodies is converted into rotational energy, and further, energy of the rotational energy is converted into thermal energy.
Implementation Method 2
the rotor member that is rotated together with the nut member is formed into the cylindrical shape so as to cover the fixed cylinder... Thus, an inertia moment of the rotor member can be set to be larger than that in a related-art damping device
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Provided is a damping device that is smaller in size and capable of increasing a damping force with respect to vibrational energy that is propagated between two structural bodies. The damping device includes: a fixed cylinder (2) that is configured to be fixed to a first structural body and formed into a cylindrical shape so as to comprise a hollow portion; a shaft member (3) that is configured to be fixed to a second structural body, the shaft member (3) being housed in the hollow portion of the fixed cylinder (2) and having an outer peripheral surface provided with a helical thread groove; a nut member (4) that is threadedly engaged with the shaft member, and converts an axial motion of the shaft member into a rotational motion; a rotor member (6) that is formed into a cylindrical shape so as to cover the fixed cylinder (2) and to form a cylindrical accommodation chamber (8) between the rotor member (6) and an outer peripheral surface of the fixed cylinder, and is rotated by the nut member (4); and viscous fluid (7) that is sealed in the cylindrical accommodation chamber (8).