Retractable Vehicle Door Handle Nonlinear Restoring Force
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Solution Overview
Problem
Retractable motor vehicle door handles can freeze in deployed states and pose a risk of finger trapping due to limited restoring force, which is inadequate for reliable retraction in icy conditions.
Innovation Solution
A handle actuation arrangement with a non-linear restoring force profile, utilizing a mechanical coupling and non-linear spring elements, ensures a higher restoring force in the standby position without increasing the risk of injury, achieved through a combination of a spring element with varying spring constants and an actuator coupling mechanism that decouples during retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear spring with higher spring constant is used to increase restoring force in standby position, then retraction reliability improves, but finger trapping risk increases
Solution Approach 1:
The patent applies a non-linear spring element that dynamically adjusts its spring constant based on handle position. The spring has a first spring constant in the rest position range and a second, higher spring constant in the standby position range. This dynamic adjustment allows the system to provide sufficient restoring force for reliable retraction while maintaining lower force near the rest position to prevent finger trapping.
Solution Approach 2:
The invention changes the physical parameter of the spring constant from a fixed linear value to a variable non-linear value. The non-linear spring element provides different spring constants (first spring constant near rest position, second spring constant near standby position) depending on the handle's position, thereby optimizing both safety and retraction reliability without requiring a uniformly high spring constant throughout the entire range.
2Strength
If restoring force is increased to ensure retraction in icy conditions, then ice-breaking capability improves, but finger trapping hazard increases
Solution Approach 1:
The non-linear spring element provides high restoring force (second spring constant) only when the handle is in the standby position or being retracted from it, which is when ice-breaking capability is needed. When the handle is near the rest position, the spring provides lower force (first spring constant), reducing the hazard to fingers. This dynamic force adjustment resolves the contradiction between ice-breaking strength and finger safety.
Solution Approach 2:
The spring element exhibits different local properties (spring constants) at different positions along its deflection range. The first spring constant applies locally near the rest position where low force is safe, while the second spring constant applies locally near the standby position where high force is needed for ice-breaking. This spatial variation in local quality allows simultaneous optimization of both safety and performance.
3Reliability
If a non-linear spring element with varying spring constants is used, then both retraction reliability and finger safety are improved, but device complexity increases
Solution Approach 1:
The non-linear spring element is designed to automatically provide the appropriate spring constant based on its own deflection state. The spring's geometry and material properties are configured such that it naturally exhibits the first spring constant at low deflection (near rest position) and the second spring constant at high deflection (near standby position). This self-regulating behavior eliminates the need for additional control mechanisms, sensors, or actuators, thereby minimizing the increase in device complexity while achieving the desired dual optimization.
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 non-linear restoring force profile enhances reliable retraction in icy conditions while minimizing the risk of finger trapping and injury, providing a safer and more effective mechanism compared to traditional linear spring systems.
Implementation Method 1
an arrangement (1) being designed to load the handle (10) with a total restoring force (f) which, starting from the standby position (X1) to back into the rest position (X0), has an at least partially nonlinear profile
Data Source
AI summary
An arrangement, the arrangement being designed for actuating a motor vehicle door, the arrangement having a handle which can be grabbed by a hand, the arrangement having an actuator which is connected to the handle via a coupling, it being possible for the handle to be moved from a rest position into a standby position by means of the actuator, the arrangement being designed to load the handle with a total restoring force which, starting from the standby position to back into the rest position, has an at least partially nonlinear profile.