Follower Pinion Position Sensing for Accurate Cabin Swing Rotation

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Solution Overview

Problem

Existing systems for determining the rotation of components in construction equipment, such as excavators, are imprecise and require costly component replacements, and sensor signals are prone to variations due to vibrations and temperature changes, necessitating a more robust and accurate position-sensing system.

Innovation Solution

A nonmetallic follower pinion is introduced to mesh with the swing gear, allowing continuous measurement of rotation independent of the swing gear's tooth count, using a sensor to detect the follower pinion's position, which can be retrofitted to existing machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is used to generate a signal related to proximity to a gear tooth, then the position can be sensed, but the signal values vary significantly due to vibrations, temperature variations, and sensor characteristics

Engineering Contradiction:
Improveposition sensing accuracyVSAvoidsignal stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A nonmetallic follower pinion is introduced as an intermediary component that meshes with the swing gear. This follower pinion rotates in response to swing gear rotation, and a sensor detects the follower pinion's position rather than directly sensing the swing gear. This intermediary approach isolates the sensor from the harsh environment and mechanical variations of the original swing gear system, providing more stable and reliable position sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the swing gear's tooth count is used for measurement, then the rotation can be determined, but the measurement accuracy is limited and component replacement is costly

Engineering Contradiction:
Improverotation measurement accuracyVSAvoidcomponent replacement cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of directly measuring the swing gear's rotation using its tooth count, a follower pinion is created as a copy that replicates the rotational motion. The sensor measures the follower pinion's position, which accurately reflects the swing gear's rotation without being limited by the swing gear's tooth count. This copying approach enables higher measurement precision and allows the follower pinion to be replaced more easily than the entire swing gear assembly.

Inventive Principle:
Principle #26Copying

3Reliability

If a position-sensing system with sensors is employed, then the actual position can be monitored, but the system is inaccurate due to variations in sensor characteristics and power supply

Engineering Contradiction:
Improveposition monitoring capabilityVSAvoidposition accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The follower pinion serves as a mechanical intermediary that converts the swing gear's rotation into a measurable position signal. By sensing the follower pinion's angular position rather than directly sensing the swing gear, the system achieves more accurate and reliable position monitoring that is less susceptible to sensor and power supply variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4276253B1Cabin swing sensor follower pinion
Publication Date: 2025.08.27 CATERPILLAR INC
  • EP4276253B1 patent drawingFigure 1
  • EP4276253B1 patent drawingFigure 2
  • EP4276253B1 patent drawingFigure 3

AI summary

A follower pinion apparatus (402) can include a swing gear system comprised of a swing gear (406) and a swing motor pinion (604). The follower pinion apparatus can also include a nonmetallic follower pinion (404) positioned to mesh with the swing gear and a sensor (702) configured to sense a position of the follower pinion.