Cam Disk Contour Transmission for Reversible On-Load Tap Changing
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Solution Overview
Problem
On-load tap-changers with energy accumulators are complex, costly, and prone to faults, making it difficult to interrupt the tap-change process in case of faults, as they rely on freewheels and accumulator springs that prevent reversal or termination of the process.
Innovation Solution
A transmission system using a cam disk with inner and outer contours followed by a roller, allowing for constant selector movement and abrupt diverter switch operation without freewheels or accumulator springs, enabling direction reversal and fault termination during tap-change processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If energy accumulators with spring and freewheels are used to achieve abrupt rotational movement, then the diverter switch operation is enabled, but the device complexity increases and fault safety decreases
Solution Approach 1:
The patent extracts and eliminates the complex energy accumulator components (spring and freewheel) from the system. Instead of using these traditional components to achieve abrupt rotational movement, the invention uses a cam mechanism with specifically contoured surfaces that directly generate the required motion profile without needing energy storage elements or one-way couplings.
Solution Approach 2:
Rather than using an energy accumulator to store and release energy for abrupt motion, the invention inverts the approach by using a cam mechanism that directly imprints the desired motion profile onto the drive shaft through its contour geometry. The motion is generated by the cam's shape rather than by energy release from a spring.
2Speed
If freewheels are used to decouple selector movement from diverter switch operation, then abrupt movement is achieved, but the ability to interrupt or reverse the process is lost
Solution Approach 1:
The patent removes the freewheel component from the system entirely. The cam mechanism directly couples the selector shaft motion to the drive shaft motion through its contour geometry, eliminating the need for one-way couplings while maintaining the ability to control the motion profile and allow reversal when needed.
Solution Approach 2:
The cam mechanism acts as an intermediary element between the selector shaft and drive shaft. Its specifically contoured surfaces translate the rotational motion into the desired abrupt movement profile while maintaining bidirectional control capability, unlike a freewheel which only allows unidirectional motion.
3Power
If accumulator springs are used to drive the drive shaft abruptly, then diverter switch operation is enabled, but costs and component quantity increase
Solution Approach 1:
The patent merges multiple functions into the cam mechanism. The cam contour simultaneously controls the timing, speed profile, and direction of the drive shaft motion, eliminating the need for separate spring, freewheel, and coupling components. This single element performs what previously required multiple interacting parts.
Solution Approach 2:
The cam mechanism serves multiple functions: it stores the motion program in its contour geometry, acts as the driving element for abrupt motion, provides the coupling between shafts, and enables control over the entire motion profile. This multi-functional element replaces several specialized 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
The solution simplifies the operation, reduces costs, and enhances safety by allowing direction reversal and fault termination in on-load tap-changers, reducing component complexity and improving reliability.
Implementation Method 1
The cam disk has an inner contour and an outer contour, the inner contour and the outer contour being configured to be followed by the roller. The roller is configured such that, in an event of a rotational movement of the cam disk, the roller follows the inner contour and the outer contour
Data Source
AI summary
An on-load tap-changer has a transmission, a motor with an output shaft, and a diverter switch with a drive shaft. The transmission has a cam disk; a drive gear wheel; and a roller coupled to the drive gear wheel. The cam disk is connected the output shaft, which lies on a rotation axis of the cam disk. The drive gear wheel is connected to the drive shaft. The cam disk has an inner and outer contour, which are followed by the roller, and which each have a first region with a constant radius of curvature and a second region in which a distance of a respective contour from the rotation axis of the cam disk changes. During a rotational movement of the cam disk, the roller follows the first region of the outer contour, the second region of the outer contour, and then the first region of the inner contour.