Battery-Free Bolt Strain Detection via Wireless Power
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Solution Overview
Problem
Existing bolts that detect fastened states require batteries, making them difficult to downsize and limiting measurement capabilities once the battery reaches the end of its life.
Innovation Solution
A bolt design that includes a strain detection unit with a resistance strain gauge, power receiving coil, and RFID tag chip, which uses wireless power and interrogation signals to convert and transmit strain data without a battery, allowing for accurate axial force detection and fastened state monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery is included in the bolt to transmit strain gauge output, then the bolt can transmit measurement data, but the circuit size increases and the bolt cannot be downsized
Solution Approach 1:
The patent extracts the battery from the bolt system and relocates it to the external measurement device. The bolt now contains only passive strain gauges and signal conditioning circuitry, while power supply and data processing functions are moved externally. This extraction resolves the contradiction by enabling data transmission without increasing bolt volume.
Solution Approach 2:
The external measurement device serves multiple functions: it provides wireless power transmission to the bolt, receives measurement data from the bolt, and processes the strain gauge signals. This multi-functional external device eliminates the need for a battery in the bolt while maintaining full measurement and transmission capabilities.
2Duration of action of stationary object
If a battery is used in the bolt, then the bolt can operate continuously, but measurements stop when the battery reaches the end of its life
Solution Approach 1:
By extracting the battery from the bolt and placing it in the external measurement device, the patent eliminates the limited lifespan constraint. The external device can be continuously powered without compromising the bolt's measurement availability, as power is transmitted wirelessly to the bolt only when measurements are being taken.
Solution Approach 2:
The bolt performs self-service by using the externally transmitted power to operate its strain gauges and signal conditioning circuitry. The bolt does not require its own power source, eliminating battery replacement needs while maintaining continuous measurement capability through periodic wireless power transmission.
3Volume of moving object
If wireless power feed is used to power the measuring portion, then the bolt can be downsized, but power transmission requires additional system complexity
Solution Approach 1:
The patent introduces an intermediary wireless power transmission system consisting of a transmitting coil in the external device and a receiving coil in the bolt. This intermediary electromagnetic coupling enables power transfer without physical connection, downsizing the bolt while managing system complexity through standardized wireless power technology.
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
Enables accurate detection of axial forces and fastened states without battery constraints, reducing size and operational costs while maintaining measurement accuracy over time.
Implementation Method 1
The measuring portion is configured to operate by receiving a first wireless power feed
Implementation Method 2
an axial force of the shank is detected by forming a hole in the bolt, inserting and fixing a strain gauge to the hole, and detecting a strain on the bolt with the strain gauge
Implementation Method 3
The transmitting portion is configured to operate by receiving a second wireless power feed after the first wireless power feed, read the measurement data stored in the memory, and transmit the read measurement data
Data Source
AI summary
A bolt includes a body and a detecting portion. The body includes a shank and a head provided at one end of the shank. The detecting portion is configured to detect a strain in accordance with an axial force of the shank. The detecting portion includes a memory, a measuring portion, and a transmitting portion. The measuring portion is configured to operate by receiving a first wireless power feed, convert the strain into measurement data, and write the measurement data to the memory. The transmitting portion is configured to operate by receiving a second wireless power feed after the first wireless power feed, read the measurement data stored in the memory, and transmit the read measurement data.