Segmented Planetary Transmission Output Element

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Solution Overview

Problem

Existing planetary gear transmissions face challenges with one-sided accessibility, complex assembly, low performance, high wear due to unsupported output elements, and conflicting requirements for rigidity and strength, leading to increased friction losses and potential overheating.

Innovation Solution

A hollow-cylindrical base body design with internal teeth, where only one rotary body is mounted directly on the base body to handle axial forces, allowing the other to be unsupported and reducing the load on connecting elements, which are designed to bypass the unsupported body, enhancing manufacturing ease and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If both rotary bodies are mounted directly on the base body to handle axial forces, then the rigidity and strength of the transmission are improved, but the assembly becomes cumbersome and friction losses increase

Engineering Contradiction:
Improverigidity and strength of the transmissionVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The transmission is segmented into two distinct mounting configurations: one rotary body mounted directly on the base body for strength, and another rotary body mounted on the first rotary body for simplified assembly. This segmentation allows each subsystem to be optimized independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first rotary body serves as an intermediary mounting platform for the second rotary body. This intermediate structure eliminates the need for complex direct mounting of both rotary bodies to the base body, simplifying assembly while maintaining structural integrity through the gear connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If axial forces are increased to improve rigidity and strength of the gear, then the bearing performance deteriorates due to increased friction losses and potential overheating

Engineering Contradiction:
Improverigidity and strength of the gearVSAvoidfriction losses
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The force transmission path is segmented between two rotary bodies mounted in different configurations. The directly-mounted rotary body handles primary axial loads, while the second rotary body transfers additional loads through gear meshing, distributing the force burden and reducing friction at any single bearing interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mounting configuration parameter is changed from uniform direct mounting to differential mounting (one direct, one indirect). This parameter change optimizes the balance between strength and friction by allowing the indirectly-mounted rotary body to engage through gear teeth rather than bearing contact, reducing friction losses.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the output element is arranged without bearings to simplify the structure, then the manufacturing ease is improved, but the wear increases and performance decreases

Engineering Contradiction:
Improvemanufacturing easeVSAvoidperformance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The bearing support function is segmented: one rotary body receives full bearing support from the base body, while the second rotary body uses gear-tooth contact for support. This segmentation allows the second element to be manufactured without additional bearings while maintaining reliability through the load-bearing gear mesh.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gear teeth serve multiple functions: they transmit rotational motion and simultaneously provide bearing support for the second rotary body. This multi-functionality eliminates the need for separate bearing components, simplifying manufacturing while maintaining reliability through the dual-purpose gear interface.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Strength

If connecting elements are designed to transmit axial forces between rotary bodies, then the strength is improved, but the device complexity increases

Engineering Contradiction:
Improvestrength of connecting elementsVSAvoidcomplexity of connecting elements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The gear connection serves multiple functions: it transmits rotational motion between rotary bodies and simultaneously transmits axial forces. This multi-functionality eliminates the need for separate connecting elements designed specifically for axial force transmission, reducing device complexity while maintaining strength.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The functions of motion transmission and force transmission are merged into the gear interface. The gear teeth simultaneously engage for rotational drive and provide load-bearing contact for axial forces, combining what would traditionally require separate mechanisms into a single integrated connection.

Inventive Principle:
Principle #5Merging (Combining)

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

This design simplifies manufacturing and assembly, increases torsional strength, and enhances power density while reducing weight and friction losses, leading to improved transmission performance and reliability.

Implementation Method 1

At least one gear wheel which is driven by the input member and meshes with the internal toothing is arranged between the two rotary bodies

Methodology Applied
Scientific EffectGear meshing: Gear

Implementation Method 2

The input member is mounted on both sides in the rotary bodies or is only indirectly mounted on one of the two rotary bodies, or is only mounted directly on or in the base body for support against radial forces

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP2255104B1Transmission
Publication Date: 2012.07.04 SPINEA SRO
  • EP2255104B1 patent drawingFigure 1
  • EP2255104B1 patent drawingFigure 1A
  • EP2255104B1 patent drawingFigure 1a

AI summary

A transmission is described, having a main body (40), which is like a hollow cylinder and has an internal gearing (41), a rotational axis (40a) and front sides (49), and in which a driven input element (10) and an output element are rotatably supported, wherein said output element has two rotating bodies (50, 50'), which can be connected or are connected to one another non-rotatably and have a circular cross-section transversely to said rotational axis (40a), between which at least one gear wheel (30) and means (70) for converting planetary movements of said gear wheel (30) into rotational movements of said output element are disposed. In the transmission, the forces which hold together the output element and the supporting forces which act between the output element and the main body (40) are independent of one another.