Model Railway Motor Nesting in Underframe

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Solution Overview

Problem

Existing model railway vehicle models face challenges in accommodating electric motors and drive elements on small scales due to limited space, which hinders true-to-scale designs and visibility issues, especially in railcars with passenger compartments.

Innovation Solution

The electric motor is integrated into the vehicle underframe through an opening, with the motor shaft arranged at an acute angle to the longitudinal axis, allowing for a compact design that includes a worm gear for self-locking and using flexible sections to optimize space, enabling the use of simpler gears and larger flywheels for improved running characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the electric motor is mounted on top of the vehicle underframe, then the motor is easily accessible and simple to install, but the overall height of the model increases and space for passenger compartment structures is reduced

Engineering Contradiction:
Improvespace for passenger compartmentVSAvoidmotor accommodation structure
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The electric motor is nested within an opening in the vehicle underframe, with the motor shaft extending through the underframe to connect to the axle. This nesting approach allows the motor to be housed within the limited space of the model vehicle without increasing overall height, while still providing adequate space for passenger compartment structures.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The motor shaft is arranged at an acute angle to the longitudinal axis of the vehicle underframe, utilizing the vertical dimension and diagonal space rather than only horizontal alignment. This angular arrangement optimizes space utilization within the constrained volume of the model vehicle.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the motor shaft is arranged parallel to the longitudinal axis, then the drive transmission is simple, but the available length for motor and shaft within the underframe is insufficient

Engineering Contradiction:
Improveavailable length for motor and shaftVSAvoidmotor shaft arrangement
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The motor shaft is arranged at an acute angle α to the longitudinal axis of the vehicle underframe, utilizing diagonal space rather than strict parallel alignment. This angular arrangement effectively increases the available length for motor and shaft within the constrained underframe dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If conventional gears are used with the angled motor shaft, then the gear design is simple, but play and imprecise movement occur

Engineering Contradiction:
Improvemovement precisionVSAvoidgear type
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The worm gear is specifically designed with a helix angle that corresponds to the acute angle α of the motor shaft arrangement. This parameter matching eliminates play in the gear engagement and ensures precise movement transmission, while the self-locking property of the worm gear provides additional mechanical advantage.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If the electric motor is made smaller to fit the model, then the model scale accuracy is improved, but the motor lacks sufficient power and robustness

Engineering Contradiction:
Improvemodel scale accuracyVSAvoidmotor power
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

A worm gear transmission system is used to provide mechanical advantage, allowing a smaller electric motor to generate sufficient torque at the axle. The worm gear's self-locking property and high reduction ratio enable the motor to be compact while maintaining adequate power and robustness for the model vehicle.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for the creation of detailed, lifelike models on small scales without obstructing the passenger compartment, providing smooth and precise movement while reducing overall height and manufacturing costs.

Implementation Method 1

The gear is a worm gear with a worm and a worm wheel, the worm being arranged in a rotationally fixed manner on the motor shaft of the electric motor and the worm wheel being arranged in a rotationally fixed manner on one of the axes

Methodology Applied
Scientific EffectWorm gear mechanism: Worm Drive

Implementation Method 2

A flywheel is preferably arranged on the motor shaft

Methodology Applied
Scientific EffectFlywheel effect: Flywheel

Implementation Method 3

an electric motor for driving at least one of the axles being attached to the vehicle underframe

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2762215B1Vehicle model
Publication Date: 2017.06.07 VIESSMANN MODELLSPIELWAREN
  • EP2762215B1 patent drawingFigure 1~3

AI summary

The vehicle model (1) has a vehicle chassis (2) with a longitudinal axis, where two axes (7,8) are rotatably mounted at the vehicle chassis. An electric motor (11) is provided for driving one of the axes and is fixed to the vehicle chassis. The electric motor has a motor shaft which is connected with one of the axes over a transmission (19,20). The electric motor is arranged in an opening (10) of the vehicle chassis.