SMA Wire Bonding in Camera Drivers to Prevent Assembly Jamming

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Solution Overview

Problem

Conventional SMA drivers face issues during assembly due to loose SMA wires being crushed or pressed into the chassis, leading to wire breakage and jamming, which affects the assembly process and operation performance.

Innovation Solution

The SMA driver incorporates an adhesive part to bond at least a part of the SMA wire to the spring plate, ensuring the wire is not crushed or pressed into the motor chassis during assembly, using materials like jelly or damping adhesives to maintain elasticity and prevent interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the SMA wire is made longer to reduce wire breakage risk, then the reliability improves, but the wire becomes loose and may be crushed or pressed into the chassis during assembly

Engineering Contradiction:
Improvewire breakage riskVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-bonding the SMA wire to the spring plate before the housing assembly process. The adhesive part is applied to fix the SMA wire to the spring plate in advance, ensuring the wire is in a tensioned state during subsequent assembly operations. This prevents the wire from being loose and potentially crushed or pressed into the chassis during housing assembly, while still maintaining the length needed to reduce breakage risk.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the SMA wire is kept in a relaxed state with redundancy, then the stress on the wire decreases, but the wire may interfere with other components and get cut during assembly

Engineering Contradiction:
Improvewire stressVSAvoidwire interference and cut risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-bonding the SMA wire to the spring plate before housing assembly. The adhesive part fixes the wire in a tensioned state in advance, preventing it from being loose and interfering with other components during assembly. This eliminates the risk of the wire being cut while maintaining appropriate stress levels through proper tensioning.

Inventive Principle:
Principle #10Preliminary action

3Shape

If heating treatment is applied to tension the SMA wire during assembly, then the wire is in a tensioned state, but wire jamming may occur due to temperature sensitivity and phase transformation

Engineering Contradiction:
Improvewire tension stateVSAvoidwire jamming risk
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent replaces the thermal field method (heating treatment) with a chemical field method (adhesive bonding). Instead of using heat to tension and fix the SMA wire, the patent applies an adhesive part that chemically bonds the wire to the spring plate at room temperature. This avoids the wire jamming risk associated with phase transformation and temperature sensitivity while still achieving the desired tensioned state.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical-chemical parameter from temperature-based tensioning to adhesive-based bonding. By using the adhesive part, the wire is fixed in a tensioned state through chemical bonding rather than thermal expansion and phase transformation. This parameter change eliminates the wire jamming issue while maintaining the tensioned state necessary for proper function.

Inventive Principle:
Principle #35Parameter changes

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 solution reduces the risk of wire breakage and jamming, facilitating the assembly process and ensuring normal operation of the SMA driver by minimizing shaking and interference with other components.

Implementation Method 1

an adhesive part 600, where the adhesive part 600 bonds at least a part of the SMA wire 500 to at least a part of the spring plate 302

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

Thermoelastic martensite transformation is a root cause for SMA generating the features such as a shape memory effect, superelasticity, and the like

Methodology Applied
Scientific EffectThermoelastic martensite transformation: Phase Change

Implementation Method 3

the temperature-raising treatment is performed on the SMA wire in the assembly process by taking advantage of the feature that the SMA wire increases and decreases with the rise and fall of the temperature

Methodology Applied
Scientific EffectShape memory alloy effect: Shape Memory Alloy

Data Source

PatentEP4033748B1SMA driver, camera device, and electronic device
Publication Date: 2026.03.04 HUAWEI TECH CO LTD
  • EP4033748B1 patent drawingFigure 1~3
  • EP4033748B1 patent drawingFigure 4~5
  • EP4033748B1 patent drawingFigure 6

AI summary

This application relates to the field of camera technologies, and in particular, to an SMA driver, a camera apparatus, and an electronic device. The SMA driver includes a housing, a support member, a moving member, and an SMA wire. The housing covers the support member and the moving member, and the moving member can move relative to the support member. The support member includes a fixed wire connection part. The moving member includes a connected moving wire connection part and a spring plate. The SMA wire extends between the fixed wire connection part and the moving wire connection part, two ends of the SMA wire are respectively connected to the fixed wire connection part and the moving wire connection part, and the spring plate is configured to connect to a lens unit. The SMA driver further includes an adhesive part, and the adhesive part bonds at least a part of the SMA wire to at least a part of the spring plate. In this application, problems that because an SMA wire is crushed or a wire is pressed into a chassis during assembly of the SMA driver, the wire is cut due to interference with another component, and consequently the wire is dropped and broken can be effectively resolved.