Variable-Speed Speed Increaser Braking via Windage Loss
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Solution Overview
Problem
In existing variable-speed speed increasers, urgent stopping leads to excessive rotation rate of the variable-speed motor due to power supply cutoff, as the rotation rate is determined by the constant-speed motor or inertia of the rotary machine, causing the variable-speed motor to over-rotate.
Innovation Solution
Incorporating a planetary gear transmission device with a sun gear, planetary gear, internal gear, and impeller to resist the rotation of the variable-speed rotor during urgent stops, and using a blower to increase windage loss by directing wind in opposite directions with first and second impellers, and introducing gas to increase pressure within the motor casing to control rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply is cut off for urgent stopping, then the constant-speed motor and rotary machine stop, but the variable-speed motor continues to rotate excessively due to inertia
Solution Approach 1:
The patent converts the harmful effect of windage loss (air resistance) into a beneficial braking mechanism. By intentionally introducing an impeller that generates controlled windage loss, the system utilizes air resistance to provide braking torque during urgent stopping, preventing the variable-speed motor from over-rotating while maintaining reliable stoppability.
2Reliability
If impeller is added to increase windage loss for braking, then variable-speed motor over-rotation is prevented, but cooling efficiency during operation may be affected
Solution Approach 1:
The patent employs a controllable impeller that can dynamically adjust its operation mode. During normal operation, the impeller rotates in synchronism with the motor to minimize windage loss and allow effective cooling. During urgent stopping, the impeller creates controlled windage loss to provide braking torque. This dynamic adjustment resolves the contradiction between cooling efficiency and braking capability.
Solution Approach 2:
The impeller operates in different modes depending on the operational phase: during normal operation it maintains a state that allows cooling, and during stopping it transitions to a state that provides braking. This periodic switching between operational states enables the system to achieve both cooling efficiency and over-rotation protection.
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
Prevents over-rotation of the variable-speed motor during urgent stops by providing resistance through the impeller and increasing windage loss, while also allowing for effective cooling and reduced windage loss during operation.
Implementation Method 1
an impeller which is installed on the variable-speed rotor and causes windage loss by rotation of the variable-speed rotor
Implementation Method 2
using a blower to increase windage loss by directing wind in opposite directions with first and second impellers
Data Source
AI summary
A variable-speed speed increaser includes: an electric driving device which is configured to generate a rotational driving force; and a transmission device which is configured to change the speed of the rotational driving force generated by the electric driving device and transmit the changed rotation driving force to a driving target. The transmission device includes: a sun gear which is configured to rotate about an axis; a sun gear shaft which is fixed to the sun gear and extends in an axial direction around the axis; a planetary gear which is configured to mesh with the sun gear, revolve around the axis and rotate about a center line of the planetary gear; an internal gear which includes a plurality of teeth aligned annularly around the axis and is configured to mesh with the planetary gear; a planetary gear carrier; and an internal gear carrier.