Compressor-Accumulator Fixing Structure for 3N Vibration
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Solution Overview
Problem
Existing compressor units experience significant vibrations on the surface of the accumulator when operating at high speeds due to interference between the structural eigenvalue of the accumulator and the 3N-frequency component of the electric motor, particularly at frequencies between 10 Hz to 120 Hz.
Innovation Solution
The compressor unit is designed with a more rigid attachment structure by using a fixing member that is welded at four points between the compressor and the accumulator, along with a thick suction pipe, to shift the structural eigenvalue of the accumulator to a higher frequency, preventing interference with the 3N-component of the electric motor, thereby reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the accumulator is fixed to the compressor via a bracket (conventional attachment), then the structure is simple and easy to manufacture, but vibrations and noise increase significantly at high rotation speeds due to interference between the structural eigenvalue and 3N-frequency component
Solution Approach 1:
The patent changes the attachment parameters by using a fixing member with four welding points instead of a simple bracket, and increases the suction pipe thickness from conventional standards to 3mm or more. These parameter changes shift the structural eigenvalue of the accumulator to a higher frequency, preventing resonance with the 3N-frequency component of the motor and reducing vibration to 8 m/s² or less at high rotation speeds.
2Object-affected harmful factors
If the suction pipe thickness is increased to 3mm or more (rigid structure modification), then the structural eigenvalue shifts to higher frequency reducing vibration interference, but the weight and manufacturing complexity increase
Solution Approach 1:
The patent specifies precise parameter ranges to achieve the desired effect with minimal weight increase. The suction pipe thickness is set to 3mm or more (specific parameter change), and the fixing member has exactly four welding points positioned at specific locations. These controlled parameter changes shift the eigenvalue sufficiently to reduce vibration while limiting unnecessary material addition and weight increase.
3Stability of the object's composition
If a fixing member with four welding points is used to attach the accumulator to the compressor, then the attachment rigidity increases shifting eigenvalue to higher frequency, but the manufacturing complexity and time increase
Solution Approach 1:
The patent segments the attachment system into distinct functional components: a fixing member with four specific welding points that provides rigid attachment, and a thick-walled suction pipe that provides structural support. This segmentation allows each component to be optimized independently and manufactured separately, then assembled through standardized welding procedures, reducing overall manufacturing complexity despite the increased rigidity requirements.
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 configuration effectively reduces vibrations on the accumulator surface to 8 m/s^2 or less, even at high rotation speeds, by ensuring the frequency response function in the circumferential direction meets the target value of 1.0 m/s^2/N or less, thus minimizing interference and vibration increase.
Implementation Method 1
interference between the structural eigenvalue of the accumulator and the 3N-frequency component of the electric motor
Implementation Method 2
a fixing member that is welded at four points between the compressor and the accumulator
Data Source
AI summary
A compressor unit includes a compressor and an accumulator. The compressor includes a vertically elongated first casing, an electric motor, a drive shaft, and a compression mechanism. The accumulator includes a vertically elongated second casing. In a frequency range between a value three times larger than a maximum compressor rotation speed and 1.25 times greater than the value when a first part is vibrated, an index showing a frequency response function of the second casing in a circumferential direction in a second part is 1.0 m/s2/N or less. The first part is part of an upper part of a side surface of the first casing and is orthogonal to an alignment direction of the compressor and the accumulator, and the second part is part of an upper part of a side surface of the second casing and is opposed to a part facing the first casing.