Injector Needle Displacement Sensing Without Casing Modification
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Solution Overview
Problem
Conventional displacement detection devices require modifications to the injector body design to accommodate the sensor and soft magnetic material, limiting their compatibility with existing injector bodies.
Innovation Solution
A displacement detection device that uses a soft magnetic material and a sensor to detect the displacement of a needle within an injector body, with magnets and a yoke forming a uniform magnetic field outside the injector body, allowing for displacement measurement without altering the injector's design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to detect displacement, then measurement precision is improved, but the sensors are susceptible to external factors such as temperature changes and aging
Solution Approach 1:
The patent replaces optical sensors with a magnetic sensor system that uses a magnetic field generated by a coil and detected by a Hall effect sensor. This substitution eliminates the optical system's vulnerability to temperature changes and aging while maintaining displacement measurement capability through magnetic field interactions.
Solution Approach 2:
The patent changes the detection parameter from optical properties to magnetic field strength. By measuring the change in magnetic field intensity caused by the moving object's displacement, the system achieves reliable measurement without being affected by environmental factors that interfere with optical sensors.
2Measurement precision
If contact-type displacement sensors are used, then measurement precision is improved, but the sensors may come into contact with the measured object and cause damage
Solution Approach 1:
The patent replaces contact-type mechanical sensors with a non-contact magnetic field-based detection system. The coil generates a magnetic field that penetrates the measured object without physical contact, and the Hall effect sensor detects changes in this field, thereby achieving precise measurement without damaging the object.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the measurement system and the measured object. The magnetic field acts as a non-intrusive mediator that carries displacement information without requiring physical contact, thus avoiding damage to the object while enabling precise measurement.
3Object-affected harmful factors
If non-contact type sensors are used to avoid contact with measured object, then object damage is prevented, but measurement precision deteriorates
Solution Approach 1:
The patent uses a magnetic field-based detection system that combines non-contact operation with high measurement precision. The Hall effect sensor can detect subtle changes in magnetic field intensity, enabling precise displacement measurement without physical contact with the measured object.
Solution Approach 2:
The patent changes the detection mechanism to measure magnetic field intensity changes rather than relying on optical methods. This parameter change enables the system to achieve both non-contact operation and high measurement precision by detecting subtle magnetic field variations caused by object displacement.
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 displacement detection of the needle within the injector body without changing its design, reducing weight and sensitivity issues, and maintaining high accuracy and responsiveness.
Implementation Method 1
a coil is disposed at a position corresponding to a start position of the measured object in a direction in which the measured object moves, and a magnetic field is generated by the coil in response to a drive signal
Implementation Method 2
a Hall effect sensor is disposed at a position corresponding to a start position of the measured object... the Hall effect sensor detects a strength of the magnetic field generated by the coil
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
To provide a displacement detection device that detects a displacement of a measuring object housed in a casing without changing the design of the casing or while suppressing the design change of the casing. A displacement detection device 2 includes a pair of magnets 14a and 14b arranged outside an injector body 10 housing a needle 11 with a space between the magnets and forming a magnetic field in the space, a soft magnetic material 12 connected to the needle 11 inside the injector body 10 and displaced in accordance with the displacement of the needle 11 and disposed in the magnetic field formed by the pair of magnets 14a and 14b, and a sensor 13 disposed outside the injector body 10 and in the magnetic field formed by the pair of magnets 14a and 14b, and detecting a change in magnetic flux density in accordance with the displacement of the soft magnetic material 12.