Three-Piston Rotary Machine Intrados Chamber Geometry
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Solution Overview
Problem
State-of-the-art three-piston rotary machines have inefficient power/size and power/mass ratios due to unused central volumes and complex geometries, limiting their efficiency compared to four-piston machines.
Innovation Solution
A three-piston rotary machine with a stator enclosure and a rotor assembly featuring six variable-volume chambers, where the geometry of the pistons and crankshaft allows equal or greater displacement of intrados chambers compared to extrados chambers, enabling dynamic geometric complementarity and direct torque transmission without a differential system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional three-piston rotary machine geometry is used, then the machine structure is simple, but the power/size ratio and power/mass ratio are low due to unused central volumes
Solution Approach 1:
The machine is divided into six functional chambers (three extrados and three intrados chambers) instead of traditional three chambers. This segmentation allows the central volume to be utilized for additional work chambers, doubling the effective working volume and significantly improving the power/size ratio while maintaining the three-piston configuration
Solution Approach 2:
The invention transitions from utilizing only the external perimeter volume to utilizing both the external perimeter and the internal central volume of the machine. By creating intrados chambers inside the traditional extrados chambers, the design exploits the third dimension (radial depth) to maximize volume utilization, achieving up to 2.5 times higher power/size ratio
2Power
If four-piston deformable diamond machines are used, then the power/size ratio is improved, but the device complexity and manufacturing cost increase due to large number of parts
Solution Approach 1:
The three pistons in the invention serve dual functions: they form the extrados chambers for primary work and simultaneously form the boundaries of the intrados chambers for additional work. This multi-functionality allows the same components to perform multiple roles, achieving four-piston-like performance with only three pistons, thereby reducing part count and manufacturing complexity
Solution Approach 2:
The invention merges the functionality of separate extrados and intrados chambers into a unified three-piston system. Instead of requiring four separate pistons to create multiple chambers, the design combines the chamber-forming function into three multi-functional pistons that create both outer and inner chambers simultaneously, simplifying the overall structure
3Ease of manufacture
If traditional three-piston geometry is used, then the machine is easy to manufacture, but the central volume is unused or used only for secondary functions
Solution Approach 1:
The intrados chambers are designed with dynamic volume variation during the rotation cycle, allowing the central volume to actively participate in the work cycle. The chambers expand and contract in sync with the extrados chambers, converting the previously static or secondary-use central volume into an active working volume that contributes to primary functions
Solution Approach 2:
The intrados chambers are nested within the overall machine structure, utilizing the internal space between the crankshaft and the pistons. This nesting approach allows the central volume to be productively used without increasing the external dimensions of the machine, effectively doubling the working volume within the same footprint
4Productivity
If intrados chambers are added to three-piston machine, then the displacement is increased, but the geometric complexity of pistons and crankshaft increases
Solution Approach 1:
The pistons are designed with asymmetric geometry, featuring an extrados surface for the outer chambers and an intrados surface for the inner chambers. This asymmetric design allows each piston to form both types of chambers simultaneously, enabling the creation of six chambers from three pistons while managing the geometric complexity through purposeful asymmetry rather than symmetric repetition
Data Source
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AI summary
The invention concerns a rotary volumetric machine (100) with three pistons (1) comprising an enclosure (2) forming a stator in which there moves a rotating assembly (30) forming a rotor comprising a crankshaft (3) that mechanically engages with the pistons (1), the rotating assembly (30) defining, inside said enclosure (2), six chambers of variable volume of which the volume varies when the rotating assembly (30) rotates, each of the pistons (1) delimiting, with the enclosure (2), a variable volume chamber called the suction chamber (101) and two consecutive pistons (1) delimiting, with the enclosure (2) and the crankshaft (3), a variable-volume chamber called the pressure chamber (102), said machine being characterised in that the geometry of the pistons (1) and of the crankshaft (3) is designed such that each pressure chamber (102) has a capacity greater than or equal to the capacity of the suction chambers (101).