Emotor Junction Box Cooling and Compliant Phase Bar Support

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Solution Overview

Problem

In electric or hybrid electric vehicles, the phase bars connecting power electronics to electric motors can overheat and require secure retention across varying tolerances to prevent vibration, which existing methods fail to adequately address.

Innovation Solution

A junction box configuration with cooling fluid channels and insulating retainers with elastic tabs to prevent overheating and secure phase bar placement, including a first access cover with a cooling fluid channel and second access cover for connecting phase bars to power electronics, and insulating retainers that apply a preload to maintain phase bar position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If phase bars are used to connect power electronics to emotor, then electrical current can be delivered, but overheating occurs due to current loads

Engineering Contradiction:

Improveelectrical current deliveryVSAvoidphase bar temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

A thermal management system with cooling channels is introduced as an intermediary between the phase bars and the environment. The cooling channels circulate coolant to actively remove heat from the phase bars, preventing overheating while maintaining high current delivery capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A hydraulic cooling system is implemented where coolant flows through channels in the phase bar housing or adjacent structures. This fluid-based thermal management efficiently transports heat away from the high-current phase bars, resolving the overheating issue while preserving electrical performance

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Stability of the object's composition

If phase bars are securely held in junction box, then vibration can be avoided, but retention across wide tolerances is difficult

Engineering Contradiction:

Improvephase bar position stabilityVSAvoidtolerance accommodation

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The retention system uses elastic or compliant elements that can dynamically adjust to tolerance variations in phase bar positioning. These elastic retainers deform within elastic limits to accommodate manufacturing tolerances while maintaining secure retention and preventing vibration

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The retention mechanism utilizes changes in elastic deformation parameters to accommodate tolerance variations. By designing the retainers with appropriate elastic properties, the system adapts to dimensional variations in phase bars and junction box features, ensuring stable positioning across the full tolerance range

Inventive Principle:

Principle #35Parameter changes

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

The solution effectively prevents overheating and vibration of phase bars, ensuring reliable electrical connections by using cooling fluid channels to manage heat and elastic tabs to compensate for tolerance accumulations and apply a preload for secure retention.

Implementation Method 1

the first access cover includes a cooling fluid channel with a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

cooling fluid channel with a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

Elastic tabs located on at least one of the first or second insulating retainers, with the elastic tabs being configured to contact a respective inner surface of at least one of the first housing part or the second housing part, and the elastic tabs are further configured to generate a preload that presses the first and second insulating retainers toward one another and against the phase bars

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11955871B2Emotor connection arrangement with phase bar cooling and compliant internal support in the junction box

Publication Date: 2024.04.09 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

An emotor connection arrangement for connecting power electronics of an electric or hybrid electric vehicle to an emotor. The emotor connection arrangement includes a junction box configured to extend from the power electronics to the emotor, and phase bars that extend in the junction box and electrically connect the power electronics to the emotor. A first access cover is removably connected to the junction box and configured to provide access for connecting the phase bars to the emotor, and a second access cover provides similar access for connecting the phase bars to the power electronics. In order to prevent overheating, the first access cover includes a cooling fluid channel with a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return.