Reduction Gear Crown Assembly for Precise Torque Alignment
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Solution Overview
Problem
In reduction gears, particularly those with herringbone tooth configurations, precise positioning and orientation of external and internal sun gears are crucial to avoid load asymmetry, premature wear, and increased noise and vibrations, which existing methods struggle to achieve efficiently.
Innovation Solution
A method for centering and securing the first and second crowns relative to the satellites' toothings, allowing for better torque distribution and eliminating the need for assembled grinding, making the crowns interchangeable and easier to assemble and repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional centering methods (pins, fitted holes, oblong holes) are used to position and orient the first and second crowns, then the crowns can be assembled, but the alignment precision is insufficient leading to load asymmetry and premature wear
Solution Approach 1:
The method applies torques to the first and second crowns before final assembly to pre-position them in their correct angular orientations relative to the satellites. This preliminary action ensures that when the crowns are permanently fixed, they are already in the precise alignment required for balanced load distribution, eliminating the need for post-assembly grinding or adjustment.
Solution Approach 2:
The invention changes the physical state of the crowns by applying controlled torques during assembly. By varying the torque parameters applied to each crown independently, the method achieves precise angular positioning that traditional mechanical centering methods cannot attain, thereby ensuring proper alignment and preventing load asymmetry.
2Ease of manufacture
If the first and second crowns are manufactured and assembled separately with traditional centering methods, then assembly is possible, but the crowns require assembled grinding which increases complexity and reduces interchangeability
Solution Approach 1:
The crowns are pre-positioned by applying torques during the assembly process itself, eliminating the need for subsequent assembled grinding operations. This preliminary positioning action simplifies the manufacturing process by removing complex post-assembly steps while ensuring precise alignment for interchangeability.
Solution Approach 2:
The invention extracts the alignment function from the mechanical centering mechanism (pins, fitted holes) and replaces it with torque application. This separation allows the crowns to be independently manufactured and assembled without requiring complex centering features, thereby reducing assembly complexity while maintaining precision.
3Measurement precision
If pins or fitted holes are used to orient the crowns angularly, then the crowns can be positioned, but the torque distribution becomes asymmetric causing higher loads on one crown
Solution Approach 1:
By applying torques to the crowns before final assembly, the method establishes the correct angular orientation and load distribution in advance. This preliminary action ensures that when the crowns are permanently fixed, they are positioned to achieve symmetric load distribution, avoiding the load asymmetry caused by traditional pin-based centering methods.
Solution Approach 2:
The invention introduces dynamic torque application as the centering mechanism, replacing static mechanical centering (pins, fitted holes). The torques can be adjusted and optimized to achieve both precise angular orientation and balanced load distribution simultaneously, whereas static centering methods can only provide fixed geometric alignment without controlling load distribution.
Data Source
Figure 1~2
Figure 3~5b
Figure 6a~6b
AI summary
The invention relates to a method for mounting a reduction gear (10) comprising an external sun gear (14) and planet gears (16) engaging with an inner sun gear (12) and with the outer sun gear (14) and each mounted freely rotatable about a pivot (18) of a planet carrier (20), the outer sun gear (14) comprising a first ring (14a) including first gear teeth (34) and a second ring (14b) including second gear teeth (36) each engaging with first (16a) and second (16b) gear teeth of the planet gears (16). The method consists of simultaneously and independently applying a first torque to the first ring (14a) centred on the axis of the first ring (14a) and a second torque to the second ring (14b) centred on the axis of the second ring (14b), the first torque and the second torque having identical values.