Vehicle Flap Spindle Drive with Nested Planetary Gearing
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Solution Overview
Problem
Existing spindle drive assemblies for vehicle hatches are bulky and inefficient, requiring complex reduction gears that occupy significant space and complicate assembly.
Innovation Solution
A two-stage planetary gear unit with a single planet carrier and spiral-toothed gears, where planet gears are rotationally fixed and axially balanced, coupled with a compact design and efficient torque transmission using a single planet carrier and Oldham coupling, along with a laser-welded ring gear for simplicity and reduced axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional reduction gear is used to reduce the speed of the spindle drive motor, then the desired speed reduction is achieved, but the assembly becomes bulky and occupies significant space
Solution Approach 1:
The patent employs a two-stage planetary gear unit where the second planetary gear stage is nested within the first stage, sharing a common planet carrier. This nested configuration allows both gear stages to occupy the same radial space, significantly reducing the overall volume of the reduction gear compared to conventional sequential arrangements.
Solution Approach 2:
The common planet carrier serves multiple functions: it supports planet gears from both the first and second planetary gear stages, providing structural support for both gear reductions while eliminating the need for separate carriers. This multi-functional design reduces the number of components and overall assembly volume.
2Power
If a complex reduction gear is used to achieve the desired gear ratio, then the speed reduction is sufficient, but the assembly complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges two planetary gear stages into a single integrated unit with a common planet carrier. The first and second planetary gear stages are combined such that they share the same carrier structure, reducing the total number of components and simplifying manufacturing while maintaining the required gear ratio for adequate torque transmission.
Solution Approach 2:
The reduction gear is segmented into two distinct planetary gear stages with different gear ratios, allowing each stage to be optimized for specific torque and speed requirements. This segmentation enables manageable manufacturing of individual stages while achieving complex overall gear reduction through their combination.
3Adaptability or versatility
If multiple separate planet carriers are used in a two-stage planetary gear unit, then each stage can be independently designed, but the axial length and manufacturing effort increase
Solution Approach 1:
The second planetary gear stage is nested within the radial space of the first stage, both sharing the same planet carrier. This nested arrangement allows independent design optimization of each gear stage while maintaining a compact axial profile, as the stages are stacked radially rather than axially.
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 design achieves a compact, efficient, and easy-to-assemble spindle drive assembly that occupies minimal space, operates with high efficiency, and emits pleasant sounds, while ensuring reliable torque transmission and reduced assembly complexity.
Implementation Method 1
the ring gear of the motor-side planetary gear stage is mounted in a rotationally and axially fixed manner in a spindle drive assembly housing and/or in a planetary gear housing
Data Source
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AI summary
A spindle drive assembly (12) for opening and/or closing a vehicle flap is described. Said spindle drive assembly comprises a spindle (26) extending along a spindle drive axis (16) and a spindle drive motor (36) which is coupled to the spindle (26) in terms of drive and the motor shaft (38) of which is arranged substantially coaxially with respect to the spindle drive axis (16). The spindle drive motor (36) is coupled to the spindle (26) via a two-stage epicyclic gearing (58). Furthermore, a vehicle flap with such a spindle drive assembly (12) is presented. In addition, a method for installing an epicyclic gearing (58) of a spindle drive assembly (12) of this type is indicated.