Track Bolt Nut and Spacer Geometry for Clamp Load Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Track bolts in track chains of endless track drive vehicles tend to loosen over time due to vibration and wear, leading to improper positioning of track shoes and potential damage to the undercarriage, necessitating frequent maintenance.
Innovation Solution
A track nut with a non-circular perimeter and a track nut spacer are used to increase the clamp load, featuring a specific ratio of nut axial height to minimum diameter and a stepped periphery, which enhances the bolted connection's stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bearing surface area of the track nut is increased to improve clamp load retention, then the reliability of the bolted connection is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by modifying the nut height-to-diameter ratio to at least 1.20, which increases the clamp load retention without requiring an increase in bearing surface area. This dimensional parameter change resolves the contradiction by achieving improved reliability through a different geometric parameter rather than increasing bearing surface area, thus avoiding increased device complexity
Solution Approach 2:
The patent transitions from increasing bearing surface area (two-dimensional solution) to increasing nut height (three-dimensional solution). By extending the nut in the axial dimension rather than expanding the bearing face area, the patent achieves improved clamp load retention while maintaining simple nut geometry that is easy to manufacture
2Reliability
If a larger bolt and/or nut is used to increase the bearing surface area, then the clamp load retention is improved, but the adaptability to different applications is reduced
Solution Approach 1:
The patent changes the nut height-to-diameter ratio parameter to at least 1.20, which allows the same sized nut to achieve improved clamp load retention. This parameter change enables the solution to be applied across different bolt sizes and applications without requiring larger components, thus maintaining adaptability while improving reliability
Solution Approach 2:
The patent creates a universal solution that can be applied across different track chain applications by modifying the nut geometry ratio rather than requiring application-specific custom sizes. The standardized height-to-diameter ratio of at least 1.20 makes the solution broadly applicable to various bolt and nut sizes, enhancing versatility
3Reliability
If the nut axial height is increased to improve clamp load retention, then the reliability of the bolted connection is improved, but the volume of the nut increases
Solution Approach 1:
The patent optimizes the nut height-to-diameter ratio to at least 1.20, which provides a balanced increase in nut height that improves clamp load retention while minimizing volume increase. This specific ratio parameter ensures that the height increase is proportionate and efficient, achieving the desired reliability improvement with minimal additional material volume
Data Source
AI summary
A track link and track shoe bolted connection includes a track link with a clearance hole, a track bolt with a free end extending through the clearance hole, and a track nut with a top surface that is spaced away a minimum distance from the clearance hole. The track link includes a rail surface, a bottom surface, and a midplane between the rail surface and the bottom surface. The top surface of the track nut is at or above the midplane.