Eccentric Shaft Link Guide for Oscillating Displacement Machines
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Solution Overview
Problem
Existing oscillating displacement machines with eccentric shafts and piston rods face issues such as high bending moments on the crankshaft, increased costs, and large construction volumes due to the need for strong bearings and complex connecting mechanisms, which are not effectively balanced in multi-cylinder designs.
Innovation Solution
The engine employs a link guide with a slot, web, or groove, eliminating the need for connecting rods by directly coupling pistons to the eccentric shaft, allowing for a compact design with reduced components and friction through a T-slot and sliding block configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a crankshaft with several eccentrics arranged side by side is used, then the machine can achieve high performance and mass balance, but the crankshaft is exposed to high bending moments requiring strong dimensions, increasing bearing forces and construction volume
Solution Approach 1:
The patent transitions from a traditional in-line arrangement of eccentrics along the crankshaft axis to a radial arrangement where eccentrics are distributed around the circumference of a single crankshaft journal. This dimensional reconfiguration allows multiple piston rods to be driven from a single crankshaft location, reducing the overall construction volume while maintaining the ability to achieve mass balance through proper angular spacing of the eccentrics.
2Productivity
If a crankshaft with several eccentrics arranged side by side is used, then the machine can achieve high performance, but the bearing forces between crankshaft and engine housing increase, driving up costs
Solution Approach 1:
The patent combines multiple eccentric drives into a single crankshaft journal location, merging what would traditionally be separate bearing support points into one common bearing assembly. This consolidation reduces the total bearing forces that must be accommodated, as the bearing now supports the combined loads from all eccentrics at a single location rather than requiring multiple separate bearing supports along the crankshaft length.
3Reliability
If connecting rods are used to connect piston rods to the eccentric shaft, then the mechanical connection is robust, but the engine becomes expensive to manufacture and larger in size
Solution Approach 1:
The patent extracts and eliminates the connecting rod component from the drive mechanism. Instead of using traditional connecting rods to transmit motion from the eccentrics to the piston rods, the invention directly couples the piston rods to the eccentric shaft through simplified link guides and slots, removing an entire component category and reducing both complexity and manufacturing cost while maintaining reliable mechanical connection.
4Reliability
If return springs are used to press piston rods onto eccentric surfaces, then positive connection is achieved, but the spring force adds to rod force creating additional load on components
Solution Approach 1:
The patent replaces the elastic return spring mechanism with a direct geometric constraint system using link guides with slots and sliding blocks. Instead of relying on elastic forces to maintain contact between piston rods and eccentrics, the invention uses the geometry of the slot-groove interface to guide and constrain motion, eliminating the need for additional spring forces and reducing total load on components.
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 reduces the size and weight of the engine, eliminates the need for additional components, and minimizes lateral forces on the piston rods, resulting in lower production costs and improved mass balance.
Implementation Method 1
an engine for oscillating displacement machines, such as membrane pumps, with an eccentric shaft and a plurality of piston rods, the piston rods being connected to the eccentric shaft in such a way that rotation of the eccentric shaft causes an oscillating linear movement of the piston rods
Implementation Method 2
a T-slot and sliding block configuration
Data Source
Figure 1~2
Figure 3a~3c
Figure 4a~5b
AI summary
The present invention relates to a drive mechanism for oscillating positive-displacement machines, such as for example diaphragm pumps, having an eccentric shaft (2) and a multiplicity m of piston rods, wherein the piston rods are connected to the eccentric shaft in such a way that a rotation of the eccentric shaft generates an oscillating linear movement of the piston rods. In order to provide a corresponding drive mechanism which eliminates or at least reduces the described disadvantages, it is proposed according to the invention that the eccentric shaft and piston rods are connected to one another by means of a sliding-block guide.