Compressor Rotational Speed Measurement Without Permanent Magnet
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Solution Overview
Problem
Conventional compressors face issues with increased inertia, unstable balance, noise, vibration, refrigerant leakage, and high costs due to the use of permanent magnets for rotational speed measurement, which also lead to decoupling during operation.
Innovation Solution
A compressor design that utilizes a hall effect sensor to measure rotational speed without a permanent magnet, incorporating a sensor mounting groove and fixing mechanisms with hooks to prevent decoupling and refrigerant leakage, while maintaining accuracy and reducing installation time and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a permanent magnet is used for rotational speed measurement, then the rotational speed can be measured, but the inertia of the rotating body increases
Solution Approach 1:
The permanent magnet is extracted from the rotating body and relocated to the stationary clutch housing. This allows the rotational speed measurement function to be maintained while eliminating the increase in rotating mass and inertia. The hall effect sensor remains stationary and detects magnetic flux changes from the clutch's magnetic field during rotation.
Solution Approach 2:
The clutch's magnetic field serves as an intermediary to provide rotational speed information without requiring a permanent magnet on the rotating body. The hall effect sensor detects the magnetic flux changes generated by the clutch's electromagnetic field as it rotates, enabling measurement without adding mass to the rotating components.
2Measurement precision
If a permanent magnet is used for rotational speed measurement, then the rotational speed can be measured, but the balance of the rotating body becomes unstable
Solution Approach 1:
The permanent magnet is extracted from the rotating body to eliminate the imbalance it causes. By relocating the magnet to the stationary clutch housing, the rotational balance is restored while the measurement function is maintained through detection of the clutch's magnetic field variations.
3Measurement precision
If a sensor is installed through the casing to measure rotational speed, then the rotational speed can be measured, but refrigerant may leak through the through-hole
Solution Approach 1:
The sensor installation is extracted from the casing structure. Instead of creating a through-hole in the casing, the sensor is mounted on the outer surface of the casing, eliminating the refrigerant leakage path while maintaining measurement capability through external magnetic field detection.
Solution Approach 2:
The casing integrity is maintained by avoiding through-holes. The sensor is positioned externally, allowing the casing to remain a continuous barrier against refrigerant leakage while still enabling magnetic field sensing from the outside.
4Object-affected harmful factors
If the rotation measurement means is installed to prevent refrigerant leakage, then refrigerant leakage is prevented, but the installation cost and time increase
Solution Approach 1:
The sensor mounting groove and fixing mechanism are merged with the existing clutch assembly structure. The sensor is fixed to the clutch housing using the same manufacturing processes and assembly steps already required for the clutch, eliminating additional installation time and cost while maintaining refrigerant containment.
5Object-affected harmful factors
If the rotation measurement means is installed to prevent refrigerant leakage, then refrigerant leakage is prevented, but the installation cost increases
Solution Approach 1:
The sensor mounting groove and fixing features are integrated into the clutch housing manufacturing process. The same machining operations and assembly procedures used for the clutch are utilized for sensor installation, eliminating the need for separate expensive installation steps while maintaining refrigerant containment integrity.
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 allows for accurate rotational speed measurement without increasing inertia or size, preventing refrigerant leakage and decoupling, thereby reducing costs and operational issues.
Implementation Method 1
a rotation measurement means for receiving the magnetic force from the clutch to measure a change in magnetic flux according to the rotation of the rotary shaft and measure a rotational speed of the rotary shaft
Data Source
AI summary
A compressor that includes a casing, a compression mechanism provided inside the casing to compress a refrigerant, a rotary shaft transmitting a rotational force to the compression mechanism from a drive source provided outside the casing, a clutch connecting the drive source and the rotary shaft by a magnetic force generated when electric power is applied to the clutch and disconnecting the drive source and the rotary shaft by losing the magnetic force when the electric power applied thereto is cut off, and a rotation measurement means for receiving the magnetic force from the clutch to measure a change in magnetic flux according to the rotation of the rotary shaft and measure a rotational speed of the rotary shaft. Thus, it is possible to measure the rotational speed of the rotary shaft without including a permanent magnet.