Motor Bearing Switching Control for Gas Lubrication Efficiency

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Solution Overview

Problem

Existing motor bearing systems face inefficiencies due to increased fluid friction and resistance in high-speed operations when using gas-lubricated slide bearings, which worsen electric efficiency, and the reliance on pumps for forming a gas layer complicates this further, making it difficult to ensure reliable operation across varying speeds.

Innovation Solution

A motor bearing system that includes a rolling bearing and a gas-lubricated slide bearing, controlled by a detector and controller to switch between states based on rotation speed, using a pump only when necessary to maintain efficient gas lubrication, thereby optimizing electric efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a gas-lubricated slide bearing is applied in the high-speed range of the motor, then friction is reduced, but fluid friction and resistance of the lubricating gas increase, which worsens electric efficiency

Engineering Contradiction:
Improvefriction lossVSAvoidelectric efficiency
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent changes the lubrication parameter from liquid (oil) to gas (air), exploiting the lower viscosity of gas to reduce friction loss while minimizing the adverse effect of gas resistance on electric efficiency. This parameter change allows the bearing to operate more efficiently across a broader speed range.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a pump is used to apply static pressure to form a gas layer in the low-speed range, then the gas-lubricated bearing can function, but electricity consumption by the pump worsens electric efficiency

Engineering Contradiction:
Improvegas layer formation reliabilityVSAvoidelectric efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The bearing structure itself generates the necessary gas layer through its geometric design (wedge-shaped clearance) and the motor's own rotation, eliminating the need for an external pump. The system uses its own operational characteristics (rotation speed, gas supply) to create the lubricating film, achieving self-lubrication without additional energy consumption.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes pneumatic principles by supplying gas (air) to the bearing clearance and relying on the wedge effect to generate sufficient pressure for lubrication. This approach replaces mechanical pumping with a simpler gas supply system that leverages the motor's rotation to distribute the gas effectively.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Loss of energy

If the wedge effect and restriction effect are used to form a gas layer, then gas lubrication can be achieved, but these effects can only be exerted in the high-speed range, causing contact between bearing and rotary shaft in the low-speed range

Engineering Contradiction:
Improvefriction lossVSAvoidbearing operation reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent implements a dynamic switching mechanism that transitions between rolling bearing and slide bearing modes based on rotation speed. At low speeds, the rolling bearing provides reliable support; at high speeds, the slide bearing with gas lubrication takes over. This dynamic adaptation ensures optimal performance and reliability across the entire operating range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bearing system is segmented into two distinct components: a rolling bearing for low-speed operation and a slide bearing for high-speed operation. Each component is optimized for its specific speed range, and they work in sequence rather than simultaneously, allowing the system to exploit the advantages of each bearing type without compromise.

Inventive Principle:
Principle #1Segmentation

4Reliability

If a rolling bearing is used at low speed, then it functions reliably, but it has a finite life due to rolling contact fatigue

Engineering Contradiction:
Improvebearing reliabilityVSAvoidbearing life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the traditional rolling contact mechanism with a sliding contact mechanism in the high-speed range. The slide bearing with gas lubrication eliminates the rolling contact fatigue that limits the life of rolling bearings, providing infinite life potential under appropriate lubrication conditions while maintaining reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 precisely controls the bearing operation based on motor speed, minimizing electricity consumption and reducing friction, ensuring reliable operation and improved electric efficiency across different speed ranges.

Implementation Method 1

a slide bearing that is arranged in parallel with the rolling bearing on an axis of the rotary shaft to support the rotary shaft, the slide bearing being operable as a gas-lubricated bearing that achieves gaseous lubrication with gas supplied to the slide bearing

Methodology Applied
Scientific EffectGaseous lubrication: Air Lubrication

Implementation Method 2

a so-called wedge effect and a so-called restriction effect are preferably used to form this gas layer

Methodology Applied
Scientific EffectWedge effect: Wedge

Implementation Method 3

a so-called wedge effect and a so-called restriction effect are preferably used to form this gas layer

Methodology Applied
Scientific EffectRestriction effect:

Data Source

PatentEP4435283B1Motor bearing system
Publication Date: 2025.10.01 MAZDA MOTOR CORP
  • EP4435283B1 patent drawingFigure 1
  • EP4435283B1 patent drawingFigure 2
  • EP4435283B1 patent drawingFigure 3~4

AI summary

[Problem] To precisely execute control related to a bearing according to a motor rotation speed in a motor bearing system that has the bearing operable as a gas-lubricated bearing by a pump. [Solution] A motor bearing system 100 has: a slide bearing 3 operable as a gas-lubricated bearing by gas supplied from a pump 30; a rolling bearing 4; a switching mechanism 20 switching between the slide bearing and the rolling bearing; and a controller 50. When a motor rotation speed is lower than a first speed, the controller controls the switching mechanism to apply the rolling bearing. When the motor rotation speed is equal to or higher than the first speed and lower than a second speed, the controller controls the switching mechanism to apply the slide bearing and controls the pump to operate the slide bearing as a gas-lubricated bearing. When the motor rotation speed is equal to or higher than the second speed, the controller controls the switching mechanism to apply the slide bearing and stops the pump.