Viscous Rotary Damper for Vehicle Door Velocity Control
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Solution Overview
Problem
Current automotive door systems face challenges with harsh operation, excessive door bounce back, and temperature-dependent performance issues due to the use of strut systems, and existing viscous dampers are too small for larger hinge systems like tailgates and doors, failing to meet resistance torque requirements and space constraints.
Innovation Solution
A viscous rotary damper assembly comprising a cover, rotor, and viscous material is designed to provide resistance torque for controlling the velocity of external vehicle closure panels, featuring a compact cylindrical design that can be mounted to vehicle closure systems, including tailgates, doors, and trunks, with a sealing mechanism to prevent leakage and stable performance across temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If strut systems are used to provide open assist and velocity control, then the door bounce back is controlled, but the system becomes more expensive, larger, and requires more packaging space
Solution Approach 1:
The patent extracts the velocity control function from the complex strut system and implements it independently through a viscous damper integrated into the hinge assembly. This separates the damping function from the support structure, allowing a more compact overall design while maintaining door bounce back control.
Solution Approach 2:
The viscous damper is merged with the hinge assembly, combining two functions (hinge and damper) into a single integrated component. This eliminates the need for separate strut systems and reduces packaging space while maintaining velocity control capability.
2Force
If viscous dampers are scaled up to produce required resistance torque (15-25 Nm) for larger hinge systems, then the torque requirement is met, but the damper size increases and cannot meet limited space requirements
Solution Approach 1:
The patent applies local quality by optimizing the viscous material properties (viscosity, density) and the rotor geometry (surface area, shape, distribution of viscous material) to achieve high torque output from a compact volume. The rotor design features specific surface configurations that maximize shear stress generation within limited space.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the viscous material characteristics (temperature-dependent viscosity, density) and operational parameters (rotational velocity, rotor surface area) to maintain required torque output across varying conditions while keeping the damper size compact. The viscous material is selected to provide stable performance across a wide temperature range.
3Ease of operation
If mechanical devices are used to provide soft stop locations and checks, then the door position is controlled, but the operation is perceived as harsh and aggressive
Solution Approach 1:
The patent replaces traditional mechanical stop devices with a viscous damping system that provides continuous, smooth resistance throughout the door's motion range. The viscous material absorbs energy progressively, eliminating the harsh mechanical impacts and aggressive bounce back associated with conventional mechanical stops.
Solution Approach 2:
The viscous damper provides beforehand cushioning by continuously dissipating kinetic energy during door motion, preventing the accumulation of energy that would otherwise result in harsh impacts at stop locations. The damping action is active throughout the entire range of motion, cushioning the door's movement before it reaches any stop positions.
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 viscous rotary damper effectively absorbs energy and reduces door bounce back, providing stable resistance torque within limited space, improving user experience and operational efficiency across varying temperatures, while reducing the need for additional structural support and cost.
Implementation Method 1
The viscous material is disposed in a space between the cover and the rotor. The shaft connects to the rotor such that rotation of the external vehicle closure panel between a closing position and an opening position causes relative motion between the rotor and the cover of the viscous damper to provide a resistance for controlling the velocity of the external vehicle closure member.
Data Source
AI summary
An assembly to pivotally connect an external vehicle closure panel to a vehicle body includes a first hinge member that is constructed to be mounted to one of the external vehicle closure panel and the vehicle body, a second hinge member that is constructed to be mounted to the other of the external vehicle closure panel and the vehicle body, a shaft that is constructed to pivotally connect the first hinge member to the second hinge member, and a viscous rotary damper. The damper includes a cover, a rotor, and a viscous material. The shaft connects to the rotor such that rotation of the external vehicle closure panel between a closing position and an opening position causes relative motion between the rotor and the cover of the viscous damper to provide a resistance for controlling the velocity of the external vehicle closure member.