Stator Snap-Fixing for Vibration and Thermal Expansion

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Solution Overview

Problem

Existing cooling circuit pumps for motor vehicles face challenges in securely fastening the stator under vibration loads while accommodating temperature-related dimensional tolerances.

Innovation Solution

The stator is fastened to the motor housing using a snap hook device with radially distributed snap-in hooks that engage with latching lugs, supported by a one-piece injection-molded motor housing and support ring, incorporating a tolerance compensation element for thermal expansion and easy assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stator is fastened by screw or adhesive connections, then the stator is securely fixed under vibration loads, but the temperature-related dimensional tolerances cannot be compensated

Engineering Contradiction:
Improvefixation security under vibrationVSAvoidtemperature tolerance compensation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The fixation system is divided into multiple snap hooks distributed around the circumference, each independently engaging with the stator. This segmentation allows localized adjustment and compensation for thermal expansion while maintaining overall fixation security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The snap hooks are designed with elastic deformation capability, allowing them to change their engagement parameters (position, force) in response to temperature-induced dimensional changes in the stator, thereby maintaining secure fixation across temperature variations.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the stator is fastened by screw or adhesive connections, then the structure is simple, but the assembly is difficult and temperature tolerances cannot be accommodated

Engineering Contradiction:
Improvefastening structure simplicityVSAvoidassembly ease
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The snap hooks are pre-formed with latching lugs positioned to automatically engage with corresponding features on the stator during assembly. This preliminary positioning eliminates the need for complex alignment procedures required by screw connections, significantly easing assembly while maintaining structural simplicity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The traditional mechanical screw or adhesive fastening system is replaced with a snap-fit mechanical interlocking system using latching lugs. This substitution maintains structural simplicity while dramatically improving assembly ease through tool-free installation.

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

3Adaptability or versatility

If snap hooks are used to fasten the stator, then temperature tolerances can be compensated and assembly is easy, but the fixation security under vibration loads may be insufficient

Engineering Contradiction:
Improvetemperature tolerance compensationVSAvoidfixation security under vibration
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The snap hooks integrate multiple functions into a single component: they provide the latching action for easy assembly, incorporate elastic elements for temperature compensation, and maintain continuous contact pressure for vibration resistance. This merging of functions resolves the apparent contradiction between ease of assembly and fixation security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The snap hooks feature curved engagement surfaces and elastic deformation zones that allow them to conform to thermal expansion while maintaining secure contact. The curved geometry provides mechanical advantage for resisting vibration loads while accommodating dimensional changes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 provides secure fixation against vibrations and compensates for temperature-induced dimensional changes, ensuring reliable operation and easy assembly, enhancing the durability and performance of the cooling circuit pump.

Implementation Method 1

a tolerance compensation element (22) is arranged between the support ring (18) and the laminated core (11, 12, 13, 14, 15) which, as mentioned at the outset, ensures that temperature-related expansions can be absorbed

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

snap-in hooks (16) are arranged on the inside of the laminated core (11, 12, 13, 14, 15) distributed radially around the circumference of the motor housing (14) and grip the laminated core (11, 12, 13, 14, 15) in a form-fitting manner with the aid of latching lugs (20) formed at their ends

Methodology Applied
Scientific EffectMechanical Fastening: Mechanical Fastener

Data Source

PatentEP2761185B1Cooling circuit pump for a motor vehicle
Publication Date: 2019.01.09 ROBERT BOSCH GMBH
  • EP2761185B1 patent drawingFigure 1~2
  • EP2761185B1 patent drawingFigure 3~4

AI summary

The invention relates to a cooling circuit pump for a motor vehicle, having a stator which is arranged in a motor housing (14) and in which a rotatably mounted rotor is received. It is proposed that the stator (12) is received in the motor housing (14) in a positively locking manner.