Magnetic Sheave Position Sensing for Accurate CVT Displacement Detection
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Solution Overview
Problem
Existing continuously variable transmission systems face limitations in accurately detecting the position of a movable sheave due to separation of actuators and sensors, leading to reduced accuracy.
Innovation Solution
A displacement detection device incorporating a magnet and a sensor that detects changes in magnetic flux density induced by a concave or protruded surface on a rotating measuring object, allowing direct detection of the movable sheave's position within its displacement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the actuator and sensor are separated and the sensor detects the position of the arm, then the influence of dimensional errors and assembly errors is reduced, but the position detection accuracy is still limited because the movable sheave position is not directly detected
Solution Approach 1:
The invention extracts the position detection function from the actuator by using a separate sensor that directly detects the movable sheave position. The sensor detects the position of the movable sheave directly rather than detecting the arm position, thereby extracting the direct position measurement capability from the mechanical linkage system.
Solution Approach 2:
The invention introduces a magnetic field as an intermediary between the movable sheave and the sensor. A magnet is attached to the movable sheave, and a magnetic sensor detects the magnetic field changes to determine the sheave position, using the magnetic field as a mediator to achieve non-contact direct position detection.
2Measurement precision
If the sensor directly detects the movable sheave position, then the position detection accuracy is improved, but the device complexity increases due to additional components
Solution Approach 1:
The invention replaces the mechanical detection system with a magnetic field-based detection system. Instead of using mechanical linkages and contact-based sensors to detect position, the system uses a magnet attached to the movable sheave and a magnetic sensor to detect position through magnetic field changes, eliminating complex mechanical detection mechanisms.
Solution Approach 2:
The invention changes the detection parameter from mechanical position measurement to magnetic field strength measurement. By detecting changes in magnetic field strength caused by the magnet's movement with the movable sheave, the system translates mechanical position information into magnetic field parameter changes that can be measured electronically.
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 precise and direct detection of the movable sheave's position without contact, improving accuracy and reliability in continuously variable transmission systems.
Implementation Method 1
a magnet for forming a magnetic field
Implementation Method 2
detects a change in magnetic flux density due to displacement of the measuring object in the magnetic field formed by the magnet
Data Source
AI summary
A system includes a magnet for forming a magnetic field and a sensor between the magnet and an object having a circumferential surface. The object rotates around a rotation axis direction of the circumferential surface and displaces along the rotation axis direction, and an interaction between the magnet and a recess or projection portion of the circumferential surface of the object is configured to induce the magnetic field. The sensor outputs a first signal proportional to a first magnetic flux density in the rotation axis direction at a predetermined time, outputs a second signal proportional to a second magnetic flux density in a direction perpendicular to the circumferential surface of the object at the predetermined time, calculates an angle based on the first and the second magnetic flux density, and output a third signal proportional to the angle based on the first and the second magnetic flux density.