Scroll Fluid Machine Wrap Geometry for Balanced Rotation
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Solution Overview
Problem
Existing scroll type fluid machines face challenges with high thrust loads on bearings, increased upsetting moments due to radial loads, and inefficient compression spaces due to non-contributory wrap arrangements, which affect discharge volume and rotation balance.
Innovation Solution
A scroll type fluid machine design featuring a first scroll unit with uniformly spaced wraps and a second scroll unit with a cylindrical outer peripheral ring and connection block, where the wraps of the second unit are offset by 90°, providing increased strength and balanced rotation, allowing for effective compression and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the follower scroll rotates with the drive scroll to reduce closed space volume, then compression capability is improved, but thrust load increases on the end plates and bearings
Solution Approach 1:
The scroll mechanism is divided into a drive scroll and a follower scroll that rotate independently but synchronously. The drive scroll generates compression through its rotation, while the follower scroll follows without generating opposing thrust loads, segmenting the load path to reduce bearing burden while maintaining compression capability.
Solution Approach 2:
The end plates serve as intermediaries between the drive scroll and follower scroll. They transmit the rotational motion and compression force from the drive scroll to the follower scroll while distributing loads more evenly, preventing direct thrust load concentration on the bearings.
2Productivity
If the scroll wraps are elevated to increase closed space volume, then discharge volume is improved, but radial load increases and upsetting moment increases in cantilever arrangement
Solution Approach 1:
The drive scroll and follower scroll are merged into a synchronized dual-scroll system. This combination allows the closed spaces to be distributed across both scrolls, increasing total discharge volume while the shared rotation mechanism balances radial loads and reduces upsetting moments compared to a single cantilevered wrap arrangement.
3Stability of the object's composition
If two wraps with the same shape are used and combined with π/2 deviation, then structural symmetry is improved, but useless spaces between wraps are created reducing compression efficiency
Solution Approach 1:
The wraps are designed with different extension angles at their terminal portions. The first wraps have a smaller extension angle while the second wraps have a larger extension angle, creating local variations in geometry that eliminate useless spaces between wraps and improve compression efficiency while maintaining overall structural symmetry through the π/2 phase deviation.
Data Source
AI summary
A scroll type fluid machine includes a housing, a first scroll unit arranged rotatably in the housing and a second scroll unit rotating with rotation of the first scroll unit and gyrating relative to the first scroll unit to vary volumes of compression spaces. The first scroll unit includes a first wrap group including two end plates with support shafts supported rotatably by the housing and scrolled wraps arranged uniformly. The second scroll unit includes a cylindrical outer peripheral ring portion held slidably between the end plates of the first scroll unit, a connection block portion located in a center portion and a second wrap group having plural scrolled wraps extending from the ring portion to the connection block portion to define insertion spaces into which the wraps of the first wrap group are inserted and, with the first wrap group, forming compression spaces.