Scroll Compressor Counterweight Geometry for Bushing Wear Reduction
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Solution Overview
Problem
Scroll compressors experience dynamic imbalance and vibration due to centrifugal forces generated by the orbiting scroll, leading to wear between the bushing and driving bearing, which is exacerbated by improper design of counterweights.
Innovation Solution
A counterweight is designed with a mass center located above the axial lower end of the driving bearing, with a ratio of axial distance to axial height ranging from 0.1 to 0.4, and an arc-shaped main counterweight portion concentric with the rotation center, reducing the overturning moment and maintaining an oil film thickness to prevent wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a counterweight is arranged on the bushing to balance the centrifugal force generated by the orbiting scroll, then the dynamic imbalance and vibration are reduced, but the bushing may become inclined relative to the driving bearing causing wear
Solution Approach 1:
A counterweight is arranged on the bushing to generate a reverse centrifugal force that balances the centrifugal force generated by the orbiting scroll during rotation, thereby reducing dynamic imbalance and vibration of the scroll compressor
Solution Approach 2:
The axial position parameter of the counterweight mass center is optimized to be located above the axial lower end of the driving bearing, with the axial distance ratio R satisfying 0.1 ≤ R ≤ 0.4, which changes the force distribution parameters to reduce the overturning moment on the bushing
2Reliability
If the counterweight design is unreasonable, then the centrifugal force from the counterweight causes the bushing to incline and contact the driving bearing, but improving the counterweight design increases manufacturing complexity
Solution Approach 1:
By optimizing the axial position parameter (ratio R between 0.1 and 0.4) and the arc-shaped geometry of the counterweight, the design achieves a balance between reducing bushing inclination and maintaining manufacturing feasibility
Solution Approach 2:
The main counterweight portion is designed with an arc shape that is concentric with the rotation center of the rotating shaft, which simplifies the manufacturing process while effectively generating the required centrifugal force for balancing
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
The solution effectively offsets centrifugal forces, reduces wear between the bushing and driving bearing, and optimizes the design by lowering manufacturing and assembly accuracy requirements, thus enhancing the overall performance of the scroll compressor.
Implementation Method 1
a centrifugal force generated by the orbiting scroll in the movement process causes the problem of dynamic imbalance... providing a reverse centrifugal force to balance the centrifugal force generated by the orbiting scroll
Implementation Method 2
a rotating shaft transmits power via an eccentric structure (such as an eccentric crank pin) of the rotating shaft through a bushing (such as an unloading bushing for providing radial compliance) and a driving bearing
Data Source
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AI summary
A scroll compressor, the scroll compressor comprising: a rotary shaft (4); a compression mechanism (M), the compression mechanism (M) comprising a fixed scroll member (2) and a moving scroll member (3), an extension portion of the moving scroll member (3) engaging with an eccentric structure of the rotary shaft (4) by means of a driving bearing (6) and a bushing (5), the driving bearing (6) having an axial height L1; and a counterweight (9) located on the bushing (5), the center of mass of the counterweight (9) being located above the axially lower end of the driving bearing (6) and having an axial distance L2 to the axial center of the driving bearing (6), and the ratio R of the axial distance L2 to the axial height L1 satisfying: 0.1≤R≤0.4. By rationally designing the counterweight (9), while counteracting the centrifugal force of the moving scroll member (3) and allowing the bushing (5) to incline by a certain degree relative to the driving bearing (6), the scroll compressor can reduce the contact and wear between the bushing (5) and the driving bearing (6), and reduce the requirements for the manufacturing precision and the mounting precision of components such as the counterweight (9) and the bushing (5), achieving optimized system design.