Hybrid Motor Bearing Control for Speed and Radial Load
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Solution Overview
Problem
The application of a gas-lubricated bearing in high-speed motors leads to increased fluid friction and resistance, worsening electric efficiency, while the wedge and restriction effects are insufficient in low-speed ranges, and large radial loads complicate the formation of a gas layer.
Innovation Solution
A motor bearing system with a rolling bearing and a gas-lubricated slide bearing, controlled by a pump and detector, switches between operating modes based on rotation speed and radial load to optimize electric efficiency and prevent contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gas-lubricated bearing is applied in high-speed motors, then friction is reduced, but fluid friction and resistance of the lubricating gas increase, worsening electric efficiency
Solution Approach 1:
The patent changes the operating parameters of the gas-lubricated bearing by controlling the rotational speed thresholds for activation. The bearing is activated only when rotational speed exceeds a first threshold and deactivated when it falls below a second threshold, optimizing the balance between friction reduction and electric efficiency across different speed ranges
Solution Approach 2:
The system dynamically switches between different bearing modes (gas-lubricated and non gas-lubricated) based on real-time rotational speed conditions. This dynamic adaptation allows the system to utilize the gas-lubricated bearing's low friction advantage at high speeds while avoiding its detrimental fluid friction at lower speeds
2Reliability
If the wedge effect and restriction effect are used to form a gas layer, then gaseous lubrication is achieved, but these effects cannot be exerted in the low-speed range, causing bearing contact
Solution Approach 1:
The patent establishes specific rotational speed thresholds (first and second thresholds) that define the operational boundaries for the gas-lubricated bearing. By monitoring and responding to speed parameter changes, the system ensures the bearing is only activated when rotational speed is sufficient to generate the necessary wedge and restriction effects for reliable gas layer formation
3Reliability
If a pump is used to apply static pressure to form a gas layer in the low-speed range, then gaseous lubrication is achieved, but electricity consumption by the pump worsens electric efficiency
Solution Approach 1:
The system uses the motor's own rotational motion to generate the necessary effects (wedge effect and restriction effect) for gas layer formation, eliminating the need for an external pump. The rotational kinetic energy of the motor shaft itself is utilized to create the pressure differential and gas flow needed for lubrication, avoiding additional electricity consumption
Solution Approach 2:
The patent implements speed-based activation thresholds that prevent pump operation (or gas-lubricated bearing activation) at low speeds where the energy cost would exceed the benefits. The system only engages the gas-lubricated mode when rotational speed parameters indicate sufficient kinetic energy is available to maintain the gas layer without continuous pump assistance
4Loss of energy
If the gas-lubricated bearing is applied in the middle-speed range, then electric efficiency is improved, but the pump must be actuated which increases electricity consumption
Solution Approach 1:
The patent defines a middle-speed range bounded by a first threshold (lower limit) and a second threshold (upper limit). Within this parameter range, the gas-lubricated bearing is activated to reduce friction losses. The thresholds are specifically calibrated to identify the speed window where the benefits of reduced friction outweigh the costs of pump operation or gas supply system activation
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 system effectively improves electric efficiency by minimizing pump usage and preventing bearing contact, ensuring reliable operation across varying speeds and loads.
Implementation Method 1
a so-called wedge effect and a so-called restriction effect are preferably used to form this gas layer
Implementation Method 2
a so-called wedge effect and a so-called restriction effect are preferably used to form this gas layer
Implementation Method 3
the gas layer is formed according to a combination of the static pressure, which is applied by the pump
Implementation Method 4
gaseous lubrication with gas supplied to the slide bearing
Data Source
AI summary
A motor bearing system has: a slide bearing operable as a gas-lubricated bearing by gas supplied from a pump; a rolling bearing; and a controller. The controller controls the pump such that, when the motor rotation speed is equal to or higher than the first speed and is lower than the second speed, the slide bearing functions as a bearing that supports the rotary shaft and the slide bearing is operated as the gas-lubricated bearing, and when the motor rotation speed is equal to or higher than the second speed, the pump is stopped. In addition, even in the case where the motor rotation speed is equal to or higher than the second speed, the controller does not stop the pump when a radial load applied to the rotary shaft of the motor is equal to or larger than a predetermined value.