Compact Motor Assembly in Linear Motion Device

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Solution Overview

Problem

Existing linear motion devices are bulky and costly due to the arrangement of components, with the electric motor and threaded spindle being externally mounted, which occupies valuable installation space and requires extensive protection from environmental influences.

Innovation Solution

The electric motor and threaded spindle are internally arranged within the first base body, allowing the rolling elements to rotate in the first assembly, reducing the length of the guide rail and creating space for the motor, and using a U-shaped guide rail to accommodate the rolling elements and motor, ensuring protection and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the electric motor and threaded spindle are arranged externally on the first base body, then the components can be easily protected from environmental influences, but the overall length of the linear movement device becomes particularly large

Engineering Contradiction:
Improveprotection of componentsVSAvoidoverall length
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The electric motor and threaded spindle are merged into a single integrated drive unit that is arranged within the first base body, combining multiple components into one compact assembly that reduces overall device length while maintaining protection capabilities

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive unit with electric motor and threaded spindle is nested within the first base body structure, placing components inside the existing housing space rather than externally, thereby reducing the overall length of the device

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If the rolling elements rotate in the second assembly, then the guide rail can extend over the entire length of the first base body, but no space is available for accommodating the electric motor and threaded spindle

Engineering Contradiction:
Improverolling element circulationVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of having the rolling elements circulate in the second assembly (movable part), the circulation is inverted to occur in the first assembly (stationary part), specifically in a groove formed directly in the first base body, thereby creating space for the drive unit

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

Solution Approach 2:

The rolling element circulation path is repositioned from the movable second assembly to the stationary first base body structure, changing the spatial dimension of circulation from the moving side to the fixed side, which enables compact integration of the drive unit

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

3Ease of manufacture

If a standard electric motor is used without environmental protection, then the device is more cost-effective, but the motor is exposed to environmental influences

Engineering Contradiction:
Improvecost-effectivenessVSAvoidexposure to environmental influences
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The electric motor is merged with the threaded spindle and first base body into a single protected assembly, eliminating the need for separate protective housings and reducing overall cost while ensuring environmental protection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric motor is nested within the first base body structure, placing it inside the protected housing space where it is shielded from environmental influences without requiring additional protective components

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration results in a more compact, cost-effective linear motion device with improved protection of components and efficient cooling of the electric motor, enabling the use of smaller, high-power-density motors and ensuring lifelong lubrication of the screw drive.

Implementation Method 1

Between the first and second rolling surfaces, a series of spherical rolling elements is accommodated, which can circulate endlessly in the first assembly

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

The first assembly also includes a rotatable threaded spindle 24 which is in screw engagement with a threaded nut

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 3

the threaded spindle is connected to an electric motor 22 whose axis of rotation is collinear with the axis of rotation of the threaded spindle

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

the threaded spindle and the electric motor are arranged next to one another in the area of the first base body

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Data Source

PatentEP2218928B1Linear movement device with compact motor assembly
Publication Date: 2011.06.29 ROBERT BOSCH GMBH
  • EP2218928B1 patent drawingFigure 1
  • EP2218928B1 patent drawingFigure 2
  • EP2218928B1 patent drawingFigure 3

AI summary

The apparatus has a threaded spindle (95) and an electric motor (101) that are arranged in a region of a base adjacent to each other and surrounded by the base. The electric motor extends over a longitudinal section of the base while a rolling surface extends over another longitudinal section that is different from the former longitudinal section. The threaded spindle extends over the former longitudinal section and extends sectionally over the latter longitudinal section, and a rolling body continuously rotates in an assembly i.e. housing.