Spindle Motor Adapter Design for Torque and Complexity Trade-offs

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Solution Overview

Problem

Existing spindle motor designs are limited in their ability to produce a variety of configurations with a small number of parts, lacking flexibility in torque and axial force generation, and often require complex and costly adaptations for different rotor lengths and spindle types.

Innovation Solution

A spindle motor design featuring a detachable adapter that connects to both the rotor and spindle nut, allowing for different rotor lengths and spindle types to be used with a single adapter, along with a shaft seal and lubrication system for compactness and high torque, and incorporating a bellows for protection against contamination and a spring element for kinetic energy absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If different rotor lengths are used to generate different torques, then torque capability is improved, but device complexity and part variety increase

Engineering Contradiction:
Improvetorque capabilityVSAvoidpart variety
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The adapter is designed with universal interfaces that can accommodate multiple rotor lengths and different spindle types. The adapter includes a first interface for connecting to rotors of different lengths and a second interface for connecting to various spindle nuts, allowing a single adapter design to serve multiple functions and configurations, thereby reducing the need for multiple specialized parts.

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

Solution Approach 2:

The adapter acts as an intermediary component between the rotor and the spindle nut. By introducing this intermediate element, the system can accommodate variations in rotor lengths and spindle types without requiring direct customization between these components. The adapter mediates the connection, allowing the rotor and spindle nut to be independently selected from different variants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If a small internal diameter rotor is used, then the rotor can be introduced into a narrow magnetization device, but the adapter requires a stepped design with different diameters

Engineering Contradiction:
Improverotor internal diameterVSAvoidadapter structure
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The adapter features an asymmetric stepped design where different sections have different diameters optimized for their specific functions. The first interface portion has a smaller diameter to accommodate the rotor's small internal diameter for magnetization, while the second interface portion has a larger diameter to provide adequate connection surface for the spindle nut. This asymmetric design allows each section to be optimized independently for its specific requirement.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The adapter utilizes the axial dimension to resolve the diameter conflict. By creating a stepped structure along the axial direction with different diameter sections, the adapter can simultaneously accommodate the small diameter requirement for rotor connection and the larger diameter requirement for spindle nut connection, effectively adding a dimensional solution to a two-dimensional constraint problem.

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

3Reliability

If the running surface on the spindle nut is accessible from the outside, then shaft sealing can be improved, but the adapter adds axial length to the assembly

Engineering Contradiction:
Improveshaft sealingVSAvoidaxial length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The adapter is designed as a segmented component with distinct functional zones: a first interface for rotor connection, a second interface for spindle nut connection, and sealing surfaces positioned at appropriate locations. The running surface on the spindle nut remains accessible from the outside through the adapter structure, allowing shaft sealing rings to be properly positioned and function effectively, while the adapter's segmented design minimizes the overall axial length by efficiently arranging these functional zones.

Inventive Principle:
Principle #1Segmentation

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

Enables the production of multiple spindle motor variants with a small number of parts, providing high torque and axial forces, improved sealing and lubrication, and enhanced protection against contamination and mechanical stress, while allowing for precise position control and relubrication.

Implementation Method 1

The spindle motor (100) comprises a shaft seal (14, 214, 215)

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

The spindle nut (11) has at least one radial bore (13) for the passage of lubricant into the area of the meshing toothing of the spindle nut (11) and the spindle (17)

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

a spring element is provided on the spindle, which is provided for absorbing kinetic energy when a stop of the spindle motor is approached

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 4

bellows are provided on the spindle motor to protect the spindle from contamination

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 5

The adapter (8) includes a receptacle for the inner ring of a first bearing (5) for supporting the rotor (1) connected to the adapter (8) and the spindle nut (11) connected to the adapter (8)

Methodology Applied
Scientific EffectRolling friction: Ball Bearing

Data Source

PatentEP2005557B1Spindle motor
Publication Date: 2013.05.22 SEW EURODRIVE GMBH & CO KG
  • EP2005557B1 patent drawingFigure 1
  • EP2005557B1 patent drawingFigure 1a
  • EP2005557B1 patent drawingFigure 1b

AI summary

Spindle motor, comprising a stator (2), a rotor (1) which is in the form of a hollow shaft and/or has a hollow shaft section, with an adaptor (8) being detachably connected to the rotor (1), with a spindle nut (11) being detachably connected to the adaptor (8), and with the spindle nut having an (11) internal thread which interacts directly or indirectly with the external thread on a spindle which is provided within the spindle nut, such that the rotary movement of the rotor (1) is converted to a linear movement of the spindle.