Crane Swing Drive Common Frame Pinion Mounting
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Solution Overview
Problem
Large cranes face challenges in designing a swing drive system that requires multiple pinion gears to generate sufficient torque, which complicates the design due to precision mounting needs and increases the number of independent components that need to be transported and assembled, especially when tolerances in the crane structure are not perfectly aligned.
Innovation Solution
The use of at least two pinion gears mounted on a common frame with a pivoting link, allowing them to be held in appropriate contact with the ring gear without requiring precise mounting, reducing the number of separate components and simplifying the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple pinion gears are used to generate sufficient torque, then the required torque is achieved, but the device complexity increases due to precision mounting requirements and multiple independent components
Solution Approach 1:
Multiple pinion gears are mounted on a common support structure (the rotatable boom assembly) rather than being independently mounted to the carbody. This merging of mounting functions reduces the overall complexity while maintaining the torque-generating capability of multiple pinion gears.
Solution Approach 2:
The rotatable boom assembly serves multiple functions: it supports the pinion gears, provides the rotational motion for swinging the crane, and acts as the mounting structure for the pinion gears. This multi-functionality eliminates the need for separate precision mounting structures for each pinion gear.
2Power
If multiple pinion gears are used to generate sufficient torque, then the required torque is achieved, but the quantity of components increases requiring more transportation and assembly
Solution Approach 1:
Multiple pinion gears are combined on a single rotatable boom assembly, reducing the number of independent components from multiple separately mounted pinion gears to one integrated assembly containing multiple pinion gears.
3Adaptability or versatility
If pinion gears are independently mounted to accommodate tolerances, then the adaptability to structural tolerances is improved, but the device complexity and number of components increases
Solution Approach 1:
The boom assembly is made rotatable, allowing it to dynamically adjust its position and orientation to accommodate structural tolerances and misalignments. This dynamic adaptation eliminates the need for multiple independently mounted pinion gears while maintaining tolerance accommodation capability.
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
This solution allows for the use of multiple pinion gears with reduced precision in mounting, minimizing the number of components to be transported and assembled, while maintaining the necessary backlash, thus reducing costs and increasing the lifespan of the drive system.
Implementation Method 1
a swing drive system exerts a moment between the upper and lower structures. This is usually accomplished by mounting a drive gear, commonly known as a pinion gear, offset from the centerline of rotation to produce the moment. Either the lower structure or the upper structure will usually have a ring gear having teeth on a surface thereof, and the other structure will include the pinion gear that meshes with the teeth on the ring gear to provide the swing torque.
Data Source
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AI summary
A crane (10) includes i) a lower structure (12) comprising ground engaging members(14, 16) ii) an upper structure (20) rotatably connected to the lower structure (12) such that the upper structure (20) can swing with respect to the lower structure (12), wherein one of the lower structure and upper structure (12, 20) comprises a first structure having a ring gear having teeth on a surface thereof, and the other of the lower structure and upper structure (12, 20) comprises a second structure; and iii) a boom (22) pivotally mounted on the upper structure.(20) The crane (10) further includes a drive system comprising at least two pinion gears mounted on a common frame (63) and in driving contact with the ring gear teeth (35); and a link (74) connecting the frame (63) to the second structure with two pivot axes between the frame (63) and the second structure.