Bearing-Integrated Gear Failure Detection Device

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Solution Overview

Problem

Existing devices for detecting gear failure in gearboxes are unable to accurately detect failures in individual gears due to the influence of the vibration transfer path through the gearbox case, and they often require expensive and high-performance sensors.

Innovation Solution

A measuring device is attached to the bearing part of a gearbox, featuring a cover with an acceleration sensor and an angle sensor on the inner face, and a data collecting unit that obtains time-synchronous angle-acceleration pairs. This configuration allows for accurate detection of gear failure by minimizing the vibration transfer path and using a self-powered, sensor-equipped bearing device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the acceleration sensor is fixed to the case of the gearbox, then the device structure is simple and easy to manufacture, but the vibration transfer path is long and causes measurement inaccuracy due to damping and stiffness properties of the case

Engineering Contradiction:
Improvedevice structure simplicityVSAvoidvibration measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The measuring device is nested within the bearing part, with the acceleration sensor housed inside the bearing assembly rather than being mounted on the external case. This nesting approach shortens the vibration transfer path from the gear mesh to the sensor while maintaining structural simplicity, as the sensor is integrated into the existing bearing structure that is already close to the gear.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The bearing part serves as an intermediary structure that directly connects the gear to the acceleration sensor. By using the bearing assembly as the mounting platform for the sensor, the invention creates a direct vibration transfer path through the bearing components rather than through the gearbox case, thereby improving measurement accuracy while keeping the device structure relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the acceleration sensor is attached to the bearing part, then the vibration transfer path is shortened and measurement accuracy is improved, but the device complexity increases due to additional components and assembly requirements

Engineering Contradiction:
Improvevibration measurement accuracyVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The bearing part serves multiple functions: it supports the rotating shaft, provides a mounting platform for the acceleration sensor, and acts as part of the vibration transfer path. By making the bearing assembly multi-functional, the invention avoids adding separate structural components for sensor mounting, thereby improving measurement accuracy without significantly increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The measuring device is merged with the bearing part, combining the sensor housing, mounting structure, and bearing assembly into a single integrated unit. This merging eliminates the need for separate mounting brackets or additional structural elements, reducing overall device complexity while achieving the goal of shortening the vibration transfer path.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional vibration detection methods are used with long transfer paths, then inexpensive sensors can be used, but the vibration characteristics are altered by the transfer path properties making failure detection inaccurate

Engineering Contradiction:
Improvesensor costVSAvoidfailure detection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The acceleration sensor is extracted from the external case environment and placed directly within the bearing part, removing it from the influence of the gearbox case's damping and stiffness properties. This extraction allows the use of inexpensive sensors while achieving accurate failure detection, as the sensor now measures vibrations before they are significantly altered by the case transfer path.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enables accurate detection of gear failure by minimizing the influence of the vibration transfer path and allowing for the use of inexpensive sensors, such as MEMS acceleration sensors, while also providing a self-powered and wireless communication capability for the measuring device.

Implementation Method 1

an acceleration sensor provided on an inner face of the cover to measure vibrations of the bearing part

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

an angle sensor provided on the inner face of the cover to measure the angle between the outer ring and an inner ring of the bearing part

Methodology Applied
Scientific EffectAngular position measurement:

Data Source

PatentEP4127642B1Measuring device and gear failure determining device
Publication Date: 2025.04.16 NSK LTD
  • EP4127642B1 patent drawingFigure 1
  • EP4127642B1 patent drawingFigure 2
  • EP4127642B1 patent drawingFigure 3~4

AI summary

A measuring unit (100) is attached to one side face of a bearing part, which supports a shaft (24a) having a gear (22) thereon such that the shaft can rotate. The measuring device ( 100) includes a cover (110) attached to an outer ring of the bearing part to cover the side face of the bearing part, an acceleration sensor (441) provided on an inner face of the cover to measure vibrations of the bearing part, an angle sensor (443) provided on the inner face of the cover to measure an angle between the outer ring and an inner ring of the bearing part, and a data collecting unit (456) provided on the inner face of the cover to obtain the acceleration measured by the acceleration sensor and the angle measured by the angle sensor in a linked manner, sharing one common time base.