Integrated Gearbox Torque Tube for Generator Set

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Solution Overview

Problem

Existing generator sets with freestanding gearboxes face challenges in managing reaction torque stress, leading to increased weight, cost, and physical dimensions due to misalignment of crankshaft and generator shaft, requiring over-engineered mounting arrangements and larger chassis sizes, especially in high-horsepower applications.

Innovation Solution

The integration of a gearbox housing that rigidly couples the engine and generator, aligning the crankshaft, generator shaft, and gears axially, forming a torque tube structure to distribute torque load and reduce stress on the chassis, thereby optimizing structural strength and reducing the overall size and weight of the genset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a freestanding gearbox is used to couple the engine to the generator, then the gearbox can independently manage speed and torque, but the crankshaft and generator shaft become misaligned, increasing the physical dimensions of the genset

Engineering Contradiction:
Improvespeed and torque adjustmentVSAvoidphysical dimensions of genset
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The gearbox is integrated with the engine and generator assemblies to form a unified torque tube structure. The gearbox housing is rigidly coupled to both the engine and generator, merging three separate components into one integrated unit. This eliminates the need for separate mounting arrangements and reduces the overall physical dimensions while maintaining speed and torque adjustment capabilities through the gear set.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the crankshaft and generator shaft are misaligned, then the gearbox can provide flexible coupling, but the genset height and footprint increase

Engineering Contradiction:
Improvecoupling flexibilityVSAvoidgenset height
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

Instead of allowing misalignment and using the gearbox to compensate, the invention inverts the approach by ensuring precise axial alignment of the crankshaft, generator shaft, and gearbox. The integrated torque tube structure naturally accommodates torque variations without requiring offset alignment, thereby reducing genset height while maintaining coupling flexibility through the integrated design.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If an over-engineered chassis is used to support the gearbox and absorb torque stress, then the mounting stability is improved, but the weight and cost of the genset increase

Engineering Contradiction:
Improvemounting stabilityVSAvoidgenset weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The gearbox, engine, and generator are merged into a single integrated torque tube structure that is rigidly coupled together. This integration allows the entire assembly to share and distribute torque stresses internally, eliminating the need for an over-engineered chassis. The unified structure provides inherent mounting stability while reducing overall weight and cost.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If the gearbox is rigidly coupled to the engine and generator, then the torque load is distributed more efficiently, but the structural complexity of the gearbox housing increases

Engineering Contradiction:
Improvetorque load distributionVSAvoidgearbox housing structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The integrated torque tube structure is segmented into distinct coupling interfaces: the gearbox housing is rigidly coupled to the engine assembly at one end and to the generator assembly at the other end. This segmentation allows each interface to be optimized independently for torque transmission, simplifying the overall design while maintaining efficient torque load distribution through the integrated structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3542038B1Generator set integrated gearbox
Publication Date: 2023.06.07 CUMMINS POWER GENERATION LTD
  • EP3542038B1 patent drawingFigure 1
  • EP3542038B1 patent drawingFigure 2
  • EP3542038B1 patent drawingFigure 3A~3C

AI summary

A generator set comprises an engine including a crankshaft rotatable in a first direction about a longitudinal axis of the generator set, and a generator including a generator shaft. A gearbox is positioned between the engine and the generator, all mounted on a chassis. The gearbox couples the crankshaft to the generator shaft. The gearbox includes a gearbox housing having a first end and a second end. The first end is coupled to an engine first end and the second end is coupled to a generator first end. The gearbox also includes a gear set including a plurality of gears, a first gear shaft coupled to a crank shaft first end, and a second gear shaft coupled to a generator shaft first end. The crankshaft and at least a portion of the plurality of gears, and the generator shaft are axially aligned along the longitudinal axis of the generator set.