Plug-In Motor-Gearbox Coupling for Misalignment-Tolerant Assembly

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Solution Overview

Problem

Existing drive units with shaft couplings face challenges in automated assembly due to alignment and angular errors, and require significant installation space, limiting flexibility in combining different motors and transmissions.

Innovation Solution

A drive unit system featuring a clutch with a spur gear and coupling sleeve that allows for a compact, plug-in connection with play, enabling easy assembly and tolerance compensation, allowing for the combination of various motors and transmissions with different dimensions and performance data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shaft couplings are used to connect motor and gearbox, then alignment and angular errors can be compensated to a certain extent, but automated assembly becomes hardly feasible and installation space requirements increase

Engineering Contradiction:
Improvealignment error compensationVSAvoidautomated assembly feasibility
Core Design Contradiction:
ReliabilityVSExtent of automation

Solution Approach 1:

The coupling element acts as an intermediary component with a standardized interface that mediates between the motor shaft and gearbox input shaft. It provides alignment error compensation while enabling automated assembly through its standardized, pre-configured connection geometry that can be automatically positioned and secured.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling element changes the geometric parameters of the connection interface by providing a standardized flange or mounting surface with predetermined hole patterns and dimensional tolerances. This standardization allows automated assembly systems to reliably position and secure the coupling without complex alignment procedures.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If shaft couplings are used to connect motor and gearbox, then alignment errors can be compensated, but the coupling size becomes comparatively large requiring more installation space

Engineering Contradiction:
Improvealignment error compensationVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The coupling element is designed to nest efficiently with the motor and gearbox interfaces, fitting into the existing spatial envelope without requiring additional installation space. The compact design allows the coupling to be integrated within the minimal clearance between the motor shaft and gearbox input shaft.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The coupling element optimizes its dimensional parameters by providing a standardized interface with minimized outer dimensions while maintaining sufficient alignment error compensation capability. The flange diameter, thickness, and mounting hole positions are precisely defined to achieve compact size without sacrificing alignment tolerance.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If standardized interfaces are used for motor and gearbox connection, then different motors can be combined with different gearboxes, but existing couplings require complex friction-fit clamping connections

Engineering Contradiction:
Improvemotor-gearbox combination flexibilityVSAvoidclamping connection complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coupling element serves as a standardized intermediary that simplifies the connection between motor and gearbox. It replaces complex friction-fit clamping mechanisms with a simple, pre-configured interface that may use basic fasteners or even tool-free attachment methods, reducing assembly complexity while maintaining versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling element is designed as a universal component with a standardized interface that can accommodate different motor and gearbox combinations. The same coupling design can be used across multiple applications, eliminating the need for application-specific custom couplings and simplifying inventory management.

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

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 cost-effective, compact, and automated assembly of drive units with uniform torque transmission, reducing inventory needs and shortening delivery times by allowing flexible combinations of motors and transmissions.

Implementation Method 1

The spur gear also has spur teeth, and the clutch sleeve has internal teeth, which are configured to correspond to each other, form a plug connection

Methodology Applied
Scientific EffectMechanical engagement: Gear

Implementation Method 2

designed such that the spur teeth can be inserted into the internal teeth without force... enabling easy assembly and tolerance compensation

Methodology Applied
Scientific EffectTolerance compensation: Backlash

Data Source

PatentEP3992483B1Drive unit comprising a motor, a gearbox and a coupling connecting the same
Publication Date: 2024.11.06 SIEMENS AG
  • EP3992483B1 patent drawingFigure 1~2

AI summary

The invention relates to a drive unit (1) comprising a motor (10), a gearbox (20), and a clutch (30) configured to transmit a drive torque from a shaft (11) of the motor (10) to a drive shaft (21) of the gearbox (20). The clutch (30) comprises a spur gear (31) and a clutch sleeve (32), wherein the spur gear (31) is rotationally fixed to the shaft (11) of the motor (10) and the clutch sleeve (32) is rotationally fixed to the drive shaft (21) of the gearbox (20). The spur gear (31) has spur teeth and the clutch sleeve (32) has internal teeth, which are configured to correspond to each other and form a plug connection such that the spur teeth can be inserted into the internal teeth without force. With such an interface between a motor and a gearbox, different motors can be combined with different gearboxes.