Rotary Damper Locking Groove Compact Braking Torque
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Solution Overview
Problem
Conventional rotary dampers face challenges in achieving both high braking torque and compact size due to limitations in their design, particularly with the contact area between the rotor and viscous fluid, which affects the braking torque when trying to reduce the external shape for more compactness.
Innovation Solution
The rotary damper incorporates an annular locking groove and locking convex portion on the inner peripheral surface of the blade portion to maximize the contact area with the viscous fluid, while maintaining a compact design by strategically placing these features to increase the braking torque without expanding the external shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the external shape of the rotary damper is reduced to make it compact, then the size of the damper is reduced, but the contact area between the rotor and viscous fluid decreases leading to reduced braking torque
Solution Approach 1:
The rotor is nested inside the housing with the blade portion extending into the liquid chamber, allowing the rotor to be contained within the compact housing volume while maintaining sufficient contact area with the viscous fluid for effective braking torque generation
Solution Approach 2:
The blade portion of the rotor is designed to extend in the axial direction into the liquid chamber, utilizing the third dimension (depth) to maximize the contact area between the rotor and viscous fluid without increasing the radial or lateral dimensions of the overall damper assembly
2Stability of the object's composition
If a locking structure is added to control the movement of the rotor relative to the housing, then the rotor position is controlled, but the contact area between the rotor blade and viscous fluid is reduced leading to smaller braking torque
Solution Approach 1:
The locking structure is segmented into discrete locking portions on the rotor and corresponding locking grooves on the housing, allowing the rotor to be locked at specific angular positions while maintaining continuous contact between the blade portion and viscous fluid for effective braking torque generation
Solution Approach 2:
The locking portions and locking grooves are positioned at specific locations on the rotor and housing that do not interfere with the blade portion's contact area with the viscous fluid, allowing localized locking function without compromising the overall braking performance
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 allows for both high braking torque and a more compact size by optimizing the contact area between the blade portion and the viscous fluid, ensuring effective rotational resistance while minimizing the damper's size.
Implementation Method 1
due to a fluid resistance (an internal frictional resistance) of the viscous fluid, there is generated a braking torque between the rotations of the rotor and the housing
Implementation Method 2
due to a fluid resistance (an internal frictional resistance) of the viscous fluid, there is generated a braking torque
Data Source
Figure 1
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Figure 3
AI summary
To obtain both a high braking torque and a more compact size in a rotary damper. A rotary damper 1 includes a housing 2 having an outer cylinder 6 and an inner cylinder 7 disposed concentrically, and a bottom plate 8 closing one end side in an axis line direction of the outer cylinder and the inner cylinder, in which a viscous fluid is filled in an annular liquid chamber 9; a rotor 3 having a cylindrical blade portion 21; an annular locking groove 16 extending in one of either a first portion 17 which is an outer peripheral surface of the inner cylinder and is disposed at an end edge portion on a side opposed to the bottom plate side, or a second portion 33 facing the first portion of an inner peripheral surface of the blade portion; a locking convex portion 32 projecting from the other of either the first portion or the second portion, and locked in the locking groove; an annular inside seal member 38 interposed between a portion on the outer peripheral surface of the inner cylinder and on the bottom plate side more than the first portion and the inner peripheral surface of the blade portion; and an annular outside seal member 37 interposed between a vicinity of the other end in the axis line direction on an inner peripheral surface of the outer cylinder, and an outer peripheral surface of the blade portion.