Straight Coil Spring Torsional Damper Design
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Solution Overview
Problem
Existing torsion dampers face limitations in stiffness performance due to geometry and dimensioning constraints, particularly at high torque levels, and exhibit hysteresis issues due to non-uniform spring stress and frictional contact.
Innovation Solution
A torsion damper design featuring a straight vacuum coil spring housed in a housing window with specific end turns and intermediate portions, allowing for bending around the axis of revolution, which increases available volume and length, reducing frictional contact and hysteresis at low torques while optimizing operation at high torques by eliminating radial contact with the inner wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If straight vacuum coil springs are used in conventional torsion dampers, then the springs work uniformly at high torque, but the geometry limits the diameter and stiffness performance is low
Solution Approach 1:
The spring is allowed to operate in a bent configuration around the axis of revolution rather than being constrained to a straight arrangement. This dimensional change enables the spring to achieve greater effective length and diameter within the same housing window, improving stiffness performance without increasing the overall damper diameter.
Solution Approach 2:
The spring is bent into a curved configuration around the axis of revolution, utilizing curvature to maximize the use of available volume. This curved arrangement allows the spring to achieve longer length and greater diameter compared to straight arrangements, thereby improving stiffness while maintaining compact overall dimensions.
2Shape
If curved coil springs are used in arcuate windows, then the diameter can be increased, but the springs are not stressed uniformly and hysteresis occurs
Solution Approach 1:
The spring configuration transitions dynamically between bent and straight states based on operating conditions. At low torque, the spring is bent around the axis; at high torque, the spring straightens out. This dynamic behavior allows the spring to maintain uniform stress distribution during compression while achieving greater diameter through the bent configuration, eliminating hysteresis throughout the operating range.
3Length of moving object
If the spring is bent around the axis of revolution, then available volume is best used and spring length increases, but frictional contact introduces hysteresis at low torques
Solution Approach 1:
The spring configuration transitions dynamically between bent and straight states based on operating conditions. At low torque, the spring is bent around the axis; at high torque, the spring straightens out. This dynamic behavior allows the spring to maintain uniform stress distribution during compression while achieving greater diameter through the bent configuration, eliminating hysteresis throughout the operating range.
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 design enhances stiffness and reduces hysteresis, particularly at high torque levels, by allowing the spring to act over its entire length without radial contact, thereby improving performance within the given outside diameter.
Implementation Method 1
springs working in compression between the web and the guide washers
Implementation Method 2
the springs are progressively compressed until they reach an end-of-travel position
Implementation Method 3
At low rpm and low torque, the springs begin to deflect under the effect of centrifugal force
Implementation Method 4
The contact between the main spring and the inner wall of the window in the middle reference position introduces friction
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A torsional damper (10) comprises a disc (38) rotating around an axis of rotation (100), and at least one spring (16) and at least one guide washer (20, 22) rotating around the axis of rotation (100) with respect to the disc (38). The disc (38) is provided with at least one housing window (42) delimited by the walls including an interior wall (42.2) radially rotated towards the exterior of the end walls (42.3, 42.4). The spring (16) is housed in the window (42) and comprises intermediate turns (16.3). The guide washer (20, 22) is provided with at least one direct abutment face (34.1) and at least one retrograde abutment face (34.2). The spring (16) is a straight empty helical spring. In the absence of torque, at least one of the intermediate turns (16.3) of the spring (16) bears radially against the internal wall (42.2) and the spring (16) is arched around the axis of rotation (100). In the direct end of stroke position, the spring (16) is straightened and bears against the retrograde abutment face (34.2) and against one of the end walls (42.3) of the window (42), parallel to the retrograde abutment face (34.2).