Wobble Plate Compressor Rotation Prevention Mechanism
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Solution Overview
Problem
Conventional wobble plate type variable displacement compressors face issues with durability, noise, and cost due to excessive surface pressure and lubrication challenges in the rotation preventing mechanism, particularly in small-sized designs.
Innovation Solution
The compressor incorporates a rotation preventing mechanism with a relative shape difference in axial cross-sectional profiles between the outer ring and sleeve, reducing surface pressure and preventing seizure and abrasion, while maintaining durability and silent performance through optimized guide grooves and ball transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Birfield type constant velocity universal joint is used as a wobble plate rotation preventing mechanism, then the compressor structure is provided with rotational support, but the number of interposed parts increases and accumulated play becomes great, resulting in insufficient vibration, noise and durability
Solution Approach 1:
The patent extracts and eliminates the unnecessary intermediate components (cage, inner ring, outer ring) from the constant velocity universal joint structure, retaining only the essential ball elements for power transmission. This reduction of interposed parts minimizes accumulated play while maintaining rotational support functionality.
Solution Approach 2:
The patent segments the complex universal joint mechanism into discrete functional elements: balls for power transmission, and direct support structures for the wobble plate and main shaft. This segmentation allows each component to perform its specific function with minimal interference from other parts.
2Power
If a Birfield type constant velocity universal joint is used for wobble plate rotation prevention, then rotational power transmission is achieved, but the contact surface between balls and guide grooves has large inclination, causing high contact load and requiring large ball size, making the structure difficult to miniaturize
Solution Approach 1:
The patent changes the geometric parameters of the guide grooves and ball contact surfaces to reduce the inclination angle. By optimizing these parameters, the contact load is minimized while maintaining sufficient power transmission capability, allowing for smaller ball sizes in compact compressor designs.
3Device complexity
If cantilever supporting is employed for the rotational main shaft, then the structure is simplified, but whirling of the main shaft becomes great, resulting in poor durability, vibration and noise
Solution Approach 1:
Instead of supporting the main shaft at one end (cantilever), the patent inverts the approach by providing support at both ends of the main shaft. This dual-support configuration eliminates excessive whirling and improves durability while maintaining structural simplicity.
4Ease of operation
If the inner ring is supported slidably in the axial direction with rotation prevention, then the mechanism allows controlled movement, but the main shaft must be made thick to ensure rigidity, increasing weight and product size
Solution Approach 1:
The patent replaces the sliding support mechanism with a direct bearing support system. This substitution eliminates the need for thick main shaft design while maintaining controlled movement and rigidity, thereby reducing weight and product size.
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 achieves uniform and continuous ball contact, reduces vibration and noise, and enhances reliability, making the compressor smaller, easier to machine, and more cost-effective.
Implementation Method 1
a plurality of balls held by the guide grooves formed in the inner ring and the outer ring at a condition of opposing each other and performing power transmission by being compressed between the guide grooves
Data Source
AI summary
A wabble plate type variable displacement compressor has a wabble plate rotation preventing mechanism including an inner ring axially movable relative to a main shaft, an outer ring connected to the wobble plate, a plurality of balls placed between guide grooves of the inner and outer rings and performing power transmission, and a sleeve axially movably engaged with the inner ring, provided so as to be axially movable together with the inner ring. A shape differs between the axial cross-sectional profiles of substantially concave spherical surfaces formed respectively in the inner periphery of the outer ring and the outer periphery of the sleeve such that the closer to the axial opposite ends of the contact portion between both the surfaces the position is, the greater the clearance between these surfaces. Implementation of the wabble plate rotation preventing mechanism in such a compressor can provide excellent durability and silent performance.