Scroll Compressor Counterweight Mounting via Eccentric Shaft Segments
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Solution Overview
Problem
Existing scroll compressor assemblies face challenges in precisely locating counterweights to effectively counteract weight imbalances, leading to vibration and noise issues due to the offset eccentric section on the drive shaft.
Innovation Solution
A novel method of mounting counterweights on a shaft using a central annular segment and an eccentric annular segment, where the counterweight engages both segments for precise location and mounting, utilizing thermal differentiation to facilitate assembly and secure the counterweight with an interference fit, minimizing the need for axial pressing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a counterweight is mounted on a shaft with an offset eccentric section to counteract weight imbalance, then vibration and noise are reduced, but precise angular positioning of the counterweight becomes difficult to achieve
Solution Approach 1:
The patent introduces an intermediary locating feature (such as a keyway, tab, or positioning protrusion) on the shaft that engages with a corresponding feature on the counterweight. This intermediary element serves as a mediator between the shaft and counterweight, automatically establishing the correct angular relationship without requiring complex alignment procedures. The locating feature physically guides the counterweight into its precise angular position during assembly, resolving the contradiction between mounting simplicity and positioning precision.
Solution Approach 2:
The shaft is pre-formed with locating features (such as eccentric annular segments, keys, or positioning surfaces) that are integrated into the shaft structure before counterweight assembly. This preliminary preparation of the shaft with built-in positioning mechanisms eliminates the need for post-assembly alignment adjustments, ensuring that the counterweight is automatically positioned at the correct angle when mounted, thereby achieving precise angular positioning without complicating the assembly process.
2Ease of operation
If thermal differentiation is used to facilitate counterweight assembly on the shaft, then assembly ease is improved, but additional manufacturing steps and process complexity are introduced
Solution Approach 1:
The patent utilizes thermal differentiation by changing the temperature parameter of either the shaft or counterweight during assembly. By heating the counterweight (or cooling the shaft), the dimensional parameters of the interfering fit are temporarily modified, allowing easy assembly. After assembly, the temperature returns to normal, creating a secure interference fit. This parameter change approach provides a simple and effective assembly method that, while adding a thermal step, avoids complex mechanical pressing equipment and alignment mechanisms.
Solution Approach 2:
The patent replaces a purely mechanical assembly system (requiring heavy pressing forces and complex alignment fixtures) with a thermally-assisted assembly system. Instead of using mechanical force to overcome the interference fit, thermal energy is used to temporarily alter the dimensions of the mating surfaces, allowing assembly with minimal force. This substitution reduces the mechanical complexity of assembly equipment while introducing a controlled thermal process.
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 approach allows for precise angular positioning of the counterweight, effectively balancing the rotating components, reducing vibration and noise by aligning the center of mass with the central axis, thereby enhancing the operational stability of the scroll compressor.
Implementation Method 1
thermally differentiating a shaft and a counterweight to facilitate assembly
Data Source
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AI summary
A counterweight mounted to a drive shaft in a scroll compressor is provided. The drive shaft has a central annular segment generally concentric about the central axis and an eccentric annular segment offset from the central axis that can be used for driving the movable scroll compressor body.. A counterweight engages the eccentric and also engages the annular segment for location and mounting of the counterweight to the shaft.