Drop-Forged Gear Rim Segments for Large Bearing Load Capacity
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Solution Overview
Problem
Existing gear rims composed of cast segments in heavy mechanical engineering, particularly for large diameter bearings, face issues such as shape and dimension changes, blowholes, and less resilient material structures during solidification, leading to high reject rates and production-related failures.
Innovation Solution
The development of a gear rim made from individual metal segments through drop forging, where each segment has a cuboid shape with a centrally located material recess and concave surface, and machined terminal surfaces for improved resistance to deformation, combined with a method involving hot forming and machining of ingots to produce dense and tough material structures, and a device using an open forging die with a hollow mold for efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cast segments are used for gear rims, then production is simpler and easier, but the material structure becomes less resilient and prone to defects like blowholes and shape changes
Solution Approach 1:
The patent changes the manufacturing parameter from casting to drop forging, fundamentally altering how the metal segments are formed. This process change transforms the material structure from a potentially defective cast microstructure to a dense, fibrous forged structure with improved mechanical properties and resilience, eliminating blowholes and shape changes while maintaining production efficiency
Solution Approach 2:
The drop forging process utilizes phase transition by heating the metal to austenite phase before forging, allowing the material to be shaped under pressure and then cooled to form a refined grain structure. This thermal-mechanical process creates a superior material structure compared to casting, achieving both reliability and manufacturing efficiency
2Loss of substance
If traditional casting is used for gear rim segments, then material loss is higher due to rejects and defects, but the production process is less complex
Solution Approach 1:
By changing from casting to drop forging, the patent achieves near-net-shape forming with significantly reduced material waste. The forging process allows precise control of material flow and density, minimizing defects that would lead to rejects and requiring less post-processing, thereby reducing overall material loss despite increased process complexity
Solution Approach 2:
The drop forging process performs preliminary shaping and densification of the metal segments before final assembly. This preliminary action ensures that the material structure is optimized early in the process, preventing defects that would cause material loss and reducing the need for rework or rejection of defective parts
3Strength
If drop forging with material recess is used, then resistance to deformation is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent introduces a concave material recess in the gear rim segments, creating a curved geometric feature that enhances structural rigidity and resistance to deformation. This curved design optimizes stress distribution and structural efficiency, improving strength while the integrated forming process keeps manufacturing complexity manageable
Solution Approach 2:
The material recess creates local variation in the segment structure, concentrating material where needed for maximum strength and rigidity. This local quality enhancement optimizes the structural properties of specific areas without requiring complex overall design changes, achieving improved deformation resistance with controlled process complexity
4Adaptability or versatility
If segments are joined together to form gear rim, then adaptability and repairability are improved, but the connection strength may be reduced compared to monolithic structure
Solution Approach 1:
The patent divides the gear rim into multiple segments that can be assembled and disassembled, providing adaptability and repairability. Each segment is designed with connection surfaces and joining features that maintain structural integrity while enabling modular assembly, balancing connection strength with the benefits of segmentation for maintenance and flexibility
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 approach enhances the load-bearing capacity of gear rims by minimizing material losses and structural damage, reducing shrinkage, and providing high resistance to deformation, while allowing for efficient assembly and repair, thus improving the reliability and durability of large diameter bearings.
Implementation Method 1
each sprocket segment is at least one drop forging... the forming process performed on a drop forging, the ring gear according to the invention has an advantageously dense and tough material structure, with which a high resistance to deformation is achieved
Implementation Method 2
For hot forming, the ingots are first heated to a temperature above the recrystallization temperature of their metal. The heated ingots are then pressure-formed into the ring segment blanks by applying mechanical force in a forging process
Data Source
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AI summary
In a gear ring composed of individual gear ring segments, each gear ring segment (14) is a drop forging whose basic shape is that of a longitudinally curved cuboid. The cuboid has a material recess located centrally on one of its curved edges, which is bounded by a surface that is concave in sections. Each drop forging also has machined connecting surfaces. To manufacture the gear rings, the raw blocks are hot-formed into ring segment blanks, the ring segment blanks are machined while retaining gear ring segments (14, 21), and the gear ring segments (14, 21) are assembled to form the gear rings (22). The tool of a suitable device for this production is a forging die with a hollow form and circumferential flash formed between the die parts (27, 28).The hollow form representing a wreath segment blank has the basic shape of an elongated cuboid, and this cuboid has a reduction in the hollow form located centrally on one of its long edges. This reduction forms a convexly curved surface on the forging die, with diagonally opposite long edges on the hollow form, not affected by the reduction in the hollow form, running along the ridge of the forging die.