Floating Gearbox Alignment and Lubrication
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Solution Overview
Problem
Earth boring machines, such as roadheaders, experience misalignment and premature wear of gears due to axial and radial forces, leading to lubrication issues and potential leaks within the gearbox, which can result in failure.
Innovation Solution
A floating gearbox design that allows gears to maintain their optimal alignment by using spherical bearings and spline connections, enabling the ring gear to float independently of the housing, thus preventing misalignment and incorporating a lubrication system that uses a floating ring gear to ensure consistent lubrication despite tilting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the ring gear is affixed to the housing of the gearbox, then the structure is rigid and stable, but axial and radial forces cause misalignment of gears and components leading to abnormal wear and destruction
Solution Approach 1:
The patent applies the dynamics principle by making the ring gear floating rather than fixed to the housing. The ring gear is supported by spherical bearings that allow it to dynamically adjust its position in response to axial and radial forces, maintaining proper gear alignment while accommodating load variations. This dynamic adaptation prevents misalignment and abnormal wear.
Solution Approach 2:
The patent segments the connection between the ring gear and housing by introducing spherical bearings as intermediate elements. This segmentation allows the ring gear to be mechanically separated from direct rigid attachment to the housing, enabling independent movement and alignment adjustment while maintaining structural support.
2Adaptability or versatility
If the cutter head and gearbox are inclined with respect to horizontal during operation, then the roadheader can operate in varied terrain, but lubrication problems occur as bearings are lifted out of the lubricating oil
Solution Approach 1:
The patent introduces an intermediary lubrication system that uses a pump to deliver lubricating oil from a reservoir to the spherical bearings. This intermediary mechanism ensures continuous lubrication delivery regardless of the gearbox inclination angle, decoupling the lubrication supply from gravitational dependence and maintaining reliable bearing operation in varied terrain.
Solution Approach 2:
The patent employs a hydraulic lubrication system using a pump to circulate lubricating oil to the bearings. This hydraulic delivery mechanism overcomes gravitational effects during inclined operation, ensuring consistent lubrication supply to spherical bearings regardless of the roadheader's operating angle or terrain conditions.
3Device complexity
If internal tube connections are used within the gearbox, then the structure is compact, but vibrations cause the tube to vibrate and connections to leak allowing water entry and gearbox failure
Solution Approach 1:
The patent extracts the vulnerable internal tube connections from the gearbox and replaces them with external rigid piping. This removal of the problematic internal tubular structure eliminates the vibration-induced leakage issue while maintaining compactness through optimized external routing of water and lubrication lines that are more resistant to vibrational stresses.
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 floating gearbox design enhances load balancing, reduces wear, and prevents leaks by maintaining gear alignment and ensuring continuous lubrication, thereby extending the lifespan of gearbox components and preventing failures.
Implementation Method 1
A first pair of spherical bearings is interposed between each first planet gear and each first planet shaft. The first pair of spherical bearings is separated from each other and provides support for the first planet gear.
Implementation Method 2
The roadheader includes a cutter head, a gearbox and a motor (prime mover). When the gearing, most notably the ring gear, is affixed to the housing of the gearbox, the axial and radial forces imparted on the cutter head are transmitted to the ring gear through the housing and cause misalignment of the gears and other components.
Data Source
AI summary
An overload protection device in combination with a prime mover and gearbox transmission supplies torque through a gearbox transmission to a load. An input shaft with is driven by the prime mover and rotates therewith. An external spline on the input shaft mates with an input gear having an internal spline. Upon overload of the gearbox transmission, the input shaft fractures an annular groove in the input shaft. A bushing prevents travel of the portion of the input shaft which is driven by the prime mover and which continues to spin after the fracture.