Variable Speed-Ratio Transmission With Connecting Rod Mechanism
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Solution Overview
Problem
Existing infinitely variable transmissions are complex, poorly versatile, and unsuitable for many industrial applications due to their kinematic mechanisms, which often lead to breakage or unbalancing issues.
Innovation Solution
A compact and simple variable speed ratio transmission using a toothed wheel, planet wheels, and a connecting rod mechanism with a variation device that adjusts the spacing between the pivot axis and rotation axis, allowing for infinite variation of the transmission ratio without complex kinematic chains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex kinematic gear mechanisms (toothed wheels, cardan joints, helical screws) are used to achieve infinite variable transmission ratio, then the transmission ratio can be varied continuously, but the device complexity increases and reliability decreases due to susceptibility to breakage
Solution Approach 1:
The transmission system is divided into distinct functional modules: a first gear mechanism for speed reduction, a second gear mechanism for speed multiplication, and a variable ratio mechanism. Each module performs a specific function, allowing the complex overall function to be achieved through simpler, more reliable individual components that can be independently optimized and maintained.
Solution Approach 2:
An intermediate mechanism is introduced between the input and output shafts, consisting of a first gear mechanism connected to an intermediate shaft, which then connects to a second gear mechanism. This intermediary structure breaks the direct complex kinematic chain into manageable stages, reducing overall system complexity while maintaining the infinite variable ratio capability.
2Adaptability or versatility
If eccentric elements are used inside the kinematic chain to achieve variable transmission ratio, then the transmission ratio can be adjusted, but unbalancing forces occur which urge the bearings during introduction and/or discharge
Solution Approach 1:
The design incorporates counterbalancing mechanisms that offset the unbalancing forces generated during transmission ratio adjustment. By introducing counterweights or balancing masses that move in opposition to the eccentric elements, the net force on bearings is reduced, preventing excessive bearing loads during introduction and discharge operations.
Solution Approach 2:
The transmission mechanism uses dynamic elements such as movable gears or variable pitch mechanisms that can adjust the transmission ratio without relying solely on static eccentric positioning. This dynamic adjustment capability allows for smoother operation with reduced冲击 forces on bearings, improving reliability during ratio changes.
3Adaptability or versatility
If planet gears both inside and outside a ring gear are used to achieve infinite variable transmission ratio, then the transmission ratio can be varied continuously, but the radial dimensions increase which make the transmission poorly usable in many applications
Solution Approach 1:
The gear mechanisms are arranged in a nested configuration where the first gear mechanism and second gear mechanism are positioned concentrically or in overlapping spatial arrangements. This nesting allows multiple gear stages to occupy a smaller radial envelope, reducing the overall radial dimensions while maintaining the infinite variable ratio functionality.
Solution Approach 2:
Instead of expanding radially to accommodate multiple planet gears inside and outside the ring gear, the design transitions to an axial arrangement or uses a different spatial dimension for gear stacking. This dimensional reconfiguration reduces radial footprint while achieving the same transmission ratio variation capability.
Data Source
AI summary
A variable speed ratio transmission comprises a support structure, an input member, an output member and a plurality of planet wheels which are supported rotatably on the support structure and which receive the movement from the input member. Each of the planet wheels comprises a connecting rod which is rotatably connected thereto in the region of a first end thereof and which supports at an opposite end thereof a unidirectional connection wheel which entrains in rotation the output member. The transmission further comprises a variation device for the spacing between the pivot axis of the connecting rods and a respective rotation axis of the planet wheels.