Planetary Gearbox Carrier Plate Slots for Stiff Pin Fastening
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Solution Overview
Problem
The existing connection methods for planet pins to carrier plates in planetary gear boxes impair the stiffness of the carrier plates, leading to reduced performance and increased wear, particularly in gas turbine engines where a strong interference fit is required for the planet pins.
Innovation Solution
A new fastening concept using radially oriented slots on the carrier plates, where platforms at the ends of the planet pins are pushed into these slots, providing a connection without the need for openings in the carrier plates, thereby maintaining or enhancing the stiffness of the carrier plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If planet pins are arranged in openings of carrier plates to realize a strong interference fit, then the connection strength between planet pins and carrier plates is improved, but the stiffness of the carrier plates is reduced
Solution Approach 1:
The connection approach transitions from a through-opening design (axial dimension) to a slot design (radial dimension). The slots extend radially from the outer circumference toward the inner circumference, allowing planet pins to be inserted from the radial direction rather than through axial openings, thereby maintaining carrier plate stiffness while achieving strong connection.
Solution Approach 2:
The connection structure is segmented into slots that extend only over a portion of the carrier plate thickness rather than forming complete through-openings. This partial penetration approach divides the opening structure into segments, preserving the structural integrity and stiffness of the carrier plate while providing sufficient space for planet pin insertion and interference fit.
2Reliability
If openings are formed in carrier plates for receiving planet pins, then the planet pins can be securely fastened, but the production complexity and cost increase
Solution Approach 1:
The fastening approach changes from axial insertion through openings to radial insertion via slots. The slots extend in the radial direction from the outer circumference, allowing planet pins to be inserted from the radial direction, which simplifies the manufacturing process and eliminates the need for complex through-opening formations while maintaining secure fastening.
3Stability of the object's composition
If radially oriented slots are formed in carrier plates, then the stiffness of carrier plates is maintained, but the slots must extend only over partial thickness of the carrier plates
Solution Approach 1:
The slot structure is designed to extend only over a portion of the carrier plate thickness rather than forming complete through-openings. This segmented approach divides the opening into partial-depth slots, which maintain the structural continuity and stiffness of the carrier plate while providing sufficient radial space for planet pin insertion and interference fit engagement.
Data Source
AI summary
A planetary gear box, which has a sun gear, a plurality of planet gears, a ring gear, a plurality of planet pins an axially front carrier plate and an axially rear carrier plate, wherein the planet pins are connected to the carrier plates. Provision is made whereby the planet pins, at their axial ends, have in each case one platform, radially oriented slots are formed on the carrier plates, and the platforms are pushed via guide grooves into the radially oriented slots. The invention furthermore relates to a method for the assembly of a planetary gear box.