Slewing Ring Screw Layout for Higher Tilting Moment
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Solution Overview
Problem
Special foundation engineering machines face limitations in achieving higher maximum tilting moments due to constraints in slewing ring design, particularly in transport dimensions and screw connection characteristics, which restrict the use of larger screws and increased pitch circle diameters.
Innovation Solution
The solution involves axially offsetting tool engagements of adjacent screw connections to increase the density of screw connections without altering the pitch circle diameter, using expansion sleeves and varying screw lengths or nut designs to enhance screw preload force and flexibility, allowing for a higher number of screws in a limited space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If larger screws or increased pitch diameter are used to increase maximum tilting moment, then the load-bearing capacity of the slewing ring improves, but the transport dimensions and space constraints worsen
Solution Approach 1:
The patent applies axial offsetting of tool engagements in the third dimension (axial direction) to increase screw connection density without increasing the radial pitch circle diameter. This dimensional transition allows more screws to be arranged on the same pitch circle by staggering their axial positions, thereby increasing the maximum tilting moment while maintaining compact transport dimensions.
Solution Approach 2:
The patent changes the arrangement parameter of screw connections from coplanar to axially offset positions. By varying the axial positions of tool engagements and using expansion sleeves with different lengths, the patent optimizes the spatial distribution of screws to maximize connection density within the constrained radial dimension.
2Strength
If the number of screw connections is increased to increase maximum tilting moment, then the load-bearing capacity improves, but the minimum distance between screws increases due to tool engagement requirements
Solution Approach 1:
The patent resolves the spacing constraint by utilizing the axial dimension for tool engagement offsetting. This allows screw connections to be positioned closer together radially while maintaining sufficient axial separation for tool access, effectively reducing the minimum spacing requirement between adjacent screws on the pitch circle.
Solution Approach 2:
The patent segments the tool engagements of adjacent screw connections into different axial levels using expansion sleeves of varying lengths. This segmentation allows each screw connection to have its own axial workspace for tool engagement, enabling higher screw density without interference between adjacent tool engagements.
3Strength
If higher-strength screws are used to increase screw preload, then the maximum tilting moment capacity improves, but the risk of brittle fracture increases
Solution Approach 1:
The patent optimizes the preload force parameter by increasing the number of screw connections rather than individually increasing the strength of each screw. This distributed approach achieves the required total preload capacity while using screws with moderate strength ratings, thereby reducing the risk of brittle fracture associated with high-strength fasteners.
Data Source
Figure 1~2
Figure 3~5
Figure 6~8b
AI summary
The invention relates to a construction machine, in particular a special foundation engineering machine, with a superstructure (12) which carries a mast (3) on which a carriage (4) for receiving a work tool is movably arranged, wherein the superstructure (12) is rotatably connected to a substructure (11) via a slewing ring (6), wherein the slewing ring (6) comprises two bearing rings, namely an outer ring (61) and an inner ring (62), between which rolling elements are arranged, wherein one of the bearing rings is connected to the superstructure (12) via arc-shaped screw connections and the other bearing ring is connected to the substructure (11) via arc-shaped screw connections, wherein the screw connections each have a screwing means with a tool engagement for tightening the screw connection with a tool, characterized in that the tool engagements of at least two adjacent screw connections are arranged axially offset from each other.The invention further relates to a method for rotatably connecting the upper carriage to the undercarriage of such a construction machine.