Shape-Memory Alloy Wire Actuator for Vehicle Glove Box Latch
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Solution Overview
Problem
Existing vehicle compartment actuators lack efficient and reliable mechanisms for opening and closing glove boxes, which can be cumbersome for users and may not provide smooth operation.
Innovation Solution
A shape-memory alloy wire actuator system coupled with a latch mechanism, guided by a wire guide and controlled by a power system, allows the glove box lid to transition between closed and open positions quickly and smoothly in response to user input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional actuator mechanism is used for the glove box latch, then the structure is simple and easy to manufacture, but the operation is cumbersome and lacks smooth transition
Solution Approach 1:
The patent replaces traditional mechanical actuators (motors, linkages, springs) with a shape-memory alloy wire that uses thermal expansion and phase transformation to actuate the latch. This substitution eliminates complex mechanical components while providing smooth, controlled motion through the inherent properties of the smart material.
Solution Approach 2:
The shape-memory alloy wire changes its physical parameters (length, shape) in response to temperature changes. When heated by an electrical current, the wire transforms from a martensitic to austenitic phase, causing it to contract and pull the latch. This parameter change enables smooth actuation without mechanical complexity.
2Speed
If a shape-memory alloy wire is used to actuate the latch, then the operation becomes smooth and rapid, but the device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical actuators (motors, linkages, springs) with a shape-memory alloy wire that uses thermal expansion and phase transformation to actuate the latch. This substitution eliminates complex mechanical components while providing smooth, controlled motion through the inherent properties of the smart material.
Solution Approach 2:
The actuator operates in periodic cycles: electrical current is applied to heat the wire, causing rapid contraction to open the glove box; then the current is removed, allowing the wire to cool and return to its original length. This periodic action enables rapid, repeated opening operations.
3Force
If a shape-memory alloy wire is used, then rapid access is achieved with specific force and displacement parameters, but the energy consumption increases
Solution Approach 1:
The shape-memory alloy wire is heated to a temperature slightly above the austenitic transformation point, which is sufficient to trigger the phase change and generate the required actuation force. This partial heating approach provides the necessary 22.5 Newtons of force with minimal energy input, avoiding excessive energy consumption.
Solution Approach 2:
The actuator exploits the phase transition of the shape-memory alloy wire from martensite to austenite when heated. This phase transition causes a sudden change in the wire's shape and length, generating the force needed to open the latch rapidly. The phase transition occurs at a specific temperature threshold, allowing precise control of the actuation force.
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 enables rapid and reliable access to the glove box with a force of 22.5 Newtons and a change in length of 8 millimeters in 0.8 seconds, providing a seamless user experience and enhancing the functionality of vehicle compartments.
Implementation Method 1
an actuator including a shape-memory alloy wire coupled to the latch to move the latch in response to changes in length of the shape-memory alloy wire
Data Source
AI summary
A vehicle includes a compartment mounted to a frame of the vehicle. The compartment includes a box coupled to a vehicle in a fixed position relative to the vehicle and a latch system coupled to the glove to allow a user access to the box. The latch system includes a continuous loop of material including at least a portion that is made from shape-memory alloy wire.