Compound Planet Gear Arrangement for Balanced Load Distribution
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Solution Overview
Problem
Existing planetary gear arrangements face issues with over-determination, leading to unbalanced load and uneven wear, as well as shock absorption challenges due to transient forces, which reduces the service life and increases the size and weight of gearboxes, particularly in applications like wind turbines.
Innovation Solution
A compound planet gear arrangement with a structural body that allows precise positioning of rotational components, featuring axially connected planet gear units with primary and secondary gears, and a transmission arrangement enabling elastic rotation between them, which distributes load evenly and absorbs shock, allowing for high gear ratios and compact designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional planetary gear arrangements are used to transmit torque, then torque can be split between several gear components, but over-determination occurs leading to unbalanced load and uneven wear
Solution Approach 1:
The planet gear is divided into two separate gears: a first planet gear that meshes with the sun gear, and a second planet gear that meshes with the ring gear. These two planet gears are connected via a planet shaft, allowing independent load paths that eliminate over-determination and ensure balanced load distribution across all gear components.
2Speed
If conventional planetary gear arrangements are used, then gear ratio can be achieved, but shock absorption capabilities are insufficient due to transient forces
Solution Approach 1:
The planet shaft connecting the first and second planet gears is designed to allow limited relative movement between the gears. This dynamic capability enables the gear arrangement to absorb transient forces and shocks while maintaining the required gear ratio, improving shock absorption without sacrificing speed transformation.
3Weight of stationary object
If gearbox size is reduced to achieve compact design, then weight and volume decrease, but service life may be compromised
Solution Approach 1:
By segmenting the planet gear into two separate gears with distinct meshing relationships (sun gear and ring gear), the load is evenly distributed across all components. This balanced load distribution prevents premature wear and failure, extending service life even in compact, lightweight gearbox designs.
4Power
If high gear ratio is achieved, then torque transformation is improved, but gearbox volume and weight increase
Solution Approach 1:
The compound planet gear arrangement with two planet gears connected via a planet shaft enables high gear ratios to be achieved within a compact volume. The nested configuration of meshing gears (sun-planet-ring) maximizes torque transformation capability while minimizing the overall gearbox size and weight.
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 enhances the service life and reduces weight and size of gearboxes by ensuring even load distribution and shock absorption, enabling high energy density and speed ratios while maintaining compactness.
Implementation Method 1
a transmission arrangement which is arranged to allow a limited elastic rotation of the secondary planet teeth in relation to the primary planet gears
Data Source
Figure 1
Figure 1b
Figure 1c
AI summary
A compound planet gear arrangement (1) comprising; a housing (10) enclosing an interior space; a first rotational in- or output shaft; a ring gear which is fixed or connectable to the first in- or output shaft; a sun wheel which is connectable to a second in- or output shaft; and at least two planet gear units. Each planet gear unit comprises a primary planet gear with primary planet teeth meshing with the ring gear and a secondary planet gear with secondary planet teeth meshing with the sun wheel, the secondary planet gear being axially connected with the primary planet gear by means of a planet shaft. The planet gear arrangement comprises a structural body (16) which is formed in one piece, arranged in the interior space and fixed to the housing (10), which structural body (16) exhibits a number axial bores (20a, 20b, 22a, 22b) arranged to define the absolute and relative positions of respective bearings by which the first in- or output shaft and the planet shafts are journaled to the structural body.