Electric Scroll Compressor Dynamic Balancing via Pressure-Actuated Rotor Weight

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Solution Overview

Problem

Existing electric spiral compressors experience dynamic imbalance due to varying gas forces and operating points, leading to vibrations, noise, and increased loads on bearing elements, with balancing weights only effectively compensating for imbalances at predefined operating points.

Innovation Solution

The electric spiral compressor features a radially displaced balancing weight on the rotor, integrated with a rotor pressure chamber that adjusts based on high-pressure conditions, allowing for dynamic imbalance compensation across varying operating points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If balancing weights are designed and positioned to compensate for dynamic imbalance at a predefined operating point, then dynamic imbalance is compensated at that operating point, but at other operating points the balancing weight has significantly reduced effect or even increases dynamic imbalance

Engineering Contradiction:
Improvedynamic imbalance compensationVSAvoidoperating point adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The balancing weight is made radially displaceable on the rotor instead of being fixed, allowing it to dynamically adjust its position based on operating conditions. The high-pressure chamber fluidly connected to the balancing weight applies pressure that moves the balancing weight radially to different positions, enabling continuous adaptation to varying operating points and maintaining effective dynamic imbalance compensation across the entire operating range

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the radial position parameter of the balancing weight based on pressure conditions. The high-pressure chamber receives compressed gas from the compressor, and the varying pressure levels correspond to different operating points, automatically adjusting the balancing weight's radial position to match the current operating conditions and maintain optimal balance

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the balancing weight is fixed on the rotor, then the structure is simple, but it cannot compensate for dynamic imbalance caused by varying gas forces at different operating points

Engineering Contradiction:
Improvebalancing weight structureVSAvoiddynamic imbalance compensation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The balancing weight structure transitions from a fixed configuration to a dynamically adjustable one. The radial displacement mechanism allows the balancing weight to move along the rotor surface, and the high-pressure chamber provides the actuating force. This dynamic structure maintains reliability across varying operating conditions while adding only minimal complexity through the integration of the pressure chamber and displaceable mounting

Inventive Principle:
Principle #15Dynamics

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 design significantly reduces vibrations, noise, and loads on bearing elements across different operating points by dynamically adjusting the balancing weight to counteract changing dynamic imbalances.

Implementation Method 1

a rotor pressure chamber that is at least radially delimited by the balancing weight and is fluidly connected to the high-pressure chamber, wherein the balancing weight is radially positionable depending on the pressure prevailing in the rotor pressure chamber

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

the balancing weight is arranged in a radial home position by means of a preloaded spring element and, depending on the pressure prevailing in the rotor base chamber, in at least one radial pressure position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4341564B1Electric scroll compressor
Publication Date: 2025.05.07 PIERBURG GMBH
  • EP4341564B1 patent drawingFigure 1

AI summary

An electric scroll compressor having an electric motor (22) which has a stationary stator (24) and a rotating rotor (26), wherein the eccentric unit (50) is fastened to the rotor (26), and wherein at least one balance weight (72, 74) is arranged on the rotor (26), and having a high-pressure chamber (68) which is arranged fluidically between the compressor outlet (6) and the compressor unit (58), wherein the balance weight (72, 74) is arranged radially displaceably on the rotor (26), and the rotor has a rotor pressure chamber (88, 90) which is limited at least radially by the balance weight (72, 74) and is fluidically connected to the high-pressure chamber (68), wherein the balance weight (72, 74) can be positioned radially depending on a pressure prevailing in the rotor pressure chamber (88, 90).