Drawn Planetary Pin Assembly for Controlled Bearing Lubrication
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Solution Overview
Problem
Existing planetary bearing designs face challenges in ensuring sufficient lubrication flow, including high costs, complex assembly requirements, pin deformation, and debris issues from machining operations.
Innovation Solution
A pin assembly with a cylindrical side wall, inlet and outlet bores, and a radially extending annular groove that includes a slidable cylindrical plate to enhance lubrication flow, formed through drawing and hardening of sheet stock steel, with features like annular flanges and crimped seals to manage oil pressure and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lubrication methods (lube dams, hollow pins, cross drilled pins) are used, then lubrication flow is provided, but cost increases and assembly complexity increases
Solution Approach 1:
The pin is segmented into functional zones: a lubrication reservoir portion with internal cavities for storing lubricant, and a structural portion for mechanical support. This segmentation allows the lubrication function to be integrated into the pin structure itself rather than requiring separate lubrication delivery systems, thereby reducing assembly complexity while maintaining reliable lubrication flow to the planetary bearing.
2Reliability
If pressed ball or drawn steel plug methods are used, then lubrication is directed, but pin deformation occurs and reliability decreases
Solution Approach 1:
The lubrication reservoir is merged directly into the pin structure as an integrated component rather than being added as a separate pressed-in element. The pin includes internal cavities formed during the forging or machining process, eliminating the need for separate lubrication plugs or balls that could deform the pin or fall out, thereby maintaining both lubrication delivery reliability and pin structural integrity.
3Reliability
If multiple complex machining operations are used, then lubrication features are created, but debris and burrs are generated requiring additional operations
Solution Approach 1:
The lubrication reservoir cavities and lubricant delivery features are formed during the initial pin manufacturing process (forging or machining) before final assembly. This preliminary formation of lubrication features eliminates the need for subsequent complex drilling, tapping, or plug installation operations that would generate debris and burrs, thereby simplifying manufacturing while ensuring reliable lubrication flow paths free of contaminants.
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
The solution effectively enhances lubrication flow in planetary bearings by minimizing oil leakage and ensuring proper assembly, reducing operational friction and assembly complexities while maintaining structural integrity.
Implementation Method 1
A drawn planetary pin assembly includes a pin with a blind bore extending into the pin... lubrication flow through the pin... The width of the first plate in a direction parallel to the longitudinal center axis is less than a width of the first annular groove in the direction parallel to the longitudinal center axis so that the first plate is axially slidable within the first annular groove.
Implementation Method 2
drawing a hollow cylindrical pin from a piece of sheet stock steel, performing a forming step on the cylindrical pin
Implementation Method 3
performing a hardening step on the cylindrical pin
Data Source
AI summary
A pin assembly for use in a planetary gear including a pin including a cylindrical side wall defining a central bore that extends from a first end to a second end of the pin along its longitudinal center axis, an inlet bore, and a first annular groove that extends radially outwardly into the side wall of the pin adjacent the first end. A first cylindrical plate includes a first side wall, a second side wall, and a cylindrical outer wall extending therebetween, the first plate being disposed within the first annular groove of the pin, wherein a width of the first plate in a direction parallel to the longitudinal center axis is less than a width of the first annular groove in the direction parallel to the longitudinal center axis so that the first plate is axially slidable within the first annular groove.