Planet Pin Contour Shaping for S-Shaped Deformation Compensation
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Solution Overview
Problem
Planet pins in plain bearings experience deformations due to axial forces, leading to breakdown of the lubricating film and increased wear, particularly in highly loaded transmissions like wind turbines, where existing solutions fail to compensate for S-shaped deformations.
Innovation Solution
A planet pin with an outer contour defined by a function r(x) that varies with axial position, composed of linear, convex, and concave components to compensate for S-shaped deformations, ensuring a uniform bearing gap and reduced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spherical contour is used on the plain bearing running surface, then deflections caused by radially acting forces are compensated, but deformations caused by axially acting forces are not compensated
Solution Approach 1:
The planet pin outer contour is modified with different geometric characteristics in different axial regions. The contour includes a first longitudinal portion with one geometric characteristic and a second longitudinal portion with another geometric characteristic, allowing each region to compensate for deformations caused by axially acting forces in its specific location, thereby achieving comprehensive compensation along the entire axial length
Solution Approach 2:
The invention extends the spherical contour concept from the bearing running surface to the outer contour of the planet pin itself. By defining the outer contour with specific curved geometric characteristics in different longitudinal portions, the pin can pre-compensate for S-shaped deformations caused by axial forces, maintaining proper alignment and lubricating film distribution
2Device complexity
If a conventional cylindrical planet pin is used, then the structure is simple, but S-shaped deformations occur under load leading to lubricating film breakdown
Solution Approach 1:
The outer contour of the planet pin is pre-shaped with specific geometric characteristics before installation and operation. This preliminary geometric configuration compensates for anticipated S-shaped deformations that will occur under axial loads, ensuring that the lubricating film remains stable and prevents contact between bearing shells during actual operation
Data Source
AI summary
A planet pin includes a center axis and an outer contour that runs at a distance r(x) from the center axis. The distance r(x) is dependent on an axial position x in at least one longitudinal portion. For at least one axial position interval [x1, x2], the distance r(x), for all x∈[x1, x2], of the outer contour from the center axis is r(x)=l(x)+g(x)+o(x), where l(x) is a linear function, g is constantly zero or convex on the interval [x1, x2], and o(x0)=0 applies for at least one x0∈]x1, x2[. The function o is concave on the interval [x1, x0], convex on the interval [x0, x2], and decreasing in x0.