Electric Vehicle Reducer Hub Segmentation for Lubrication Isolation

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Solution Overview

Problem

The existing reducers for electric vehicles with built-in electric motors face issues due to the co-location of differential and brake assemblies, leading to poor lubrication, oil contamination, and risk of mechanical interference, which can cause the brake assembly to fail in the event of differential assembly component failure.

Innovation Solution

The reducer design separates the differential assembly from the brake assembly, with the differential located at one hub and the brake at the opposite hub, using a hollow shaft with splined profiles to transmit motion and a multiple-disk brake assembly with a sliding sleeve to enhance braking effectiveness, preventing oil flow obstruction and mechanical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the differential assembly and brake assembly are located on the same side at the same wheel hub, then the device complexity is reduced, but the lubrication quality deteriorates and the reliability decreases

Engineering Contradiction:

Improvestructural complexityVSAvoidoperational reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the reducer into two separate hubs: a first hub containing the differential assembly and a second hub containing the brake assembly. This segmentation physically separates the two assemblies, preventing oil contamination from brake friction material and ensuring proper lubrication of the differential assembly while maintaining a compact overall structure.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the brake assembly disks are located upstream from the epicyclic reduction gear, then the braking function is achieved, but the oil flow to the differential assembly is blocked

Engineering Contradiction:

Improvebraking functionVSAvoidlubrication quality

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The brake assembly is extracted from the traditional location upstream from the epicyclic reduction gear and relocated to the second hub, opposite to the differential assembly. This extraction eliminates the obstruction of oil flow to the differential assembly while preserving the braking function through the multiple-disk brake mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the oil level in the tank is increased to improve lubrication, then the lubrication quality improves, but the power draw increases and heat balance deteriorates

Engineering Contradiction:

Improvelubrication qualityVSAvoidpower draw

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of increasing oil level to improve lubrication (which causes negative side effects), the patent uses the separation of assemblies to convert the potential harm of oil contamination into a benefit: the differential assembly receives clean, adequate lubrication through its dedicated space, eliminating the need for increased oil level while maintaining proper lubrication quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Device complexity

If the differential and brake assemblies share the same oil tank, then the device complexity is reduced, but the oil contamination risk increases

Engineering Contradiction:

Improvestructural complexityVSAvoidoil contamination

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the reducer into two separate hubs with the differential assembly in the first hub and the brake assembly in the second hub. This physical segmentation creates separate lubrication zones, preventing friction material from the brake assembly from contaminating the oil that lubricates the differential assembly, while maintaining structural compactness.

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

This design improves lubrication and prevents contamination, ensuring safe and effective operation by isolating the differential and brake assemblies, reducing the risk of mechanical interference and enhancing braking performance.

Implementation Method 1

The hollow shaft with splined profiles to transmit motion

Methodology Applied

Scientific EffectMechanical coupling through splined profiles: Mechanical Force

Implementation Method 2

multiple-disk brake assembly with a sliding sleeve to enhance braking effectiveness, preventing oil flow obstruction and mechanical interference

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP2548753B1Reducer with integral electric motor for electric vehicles

Publication Date: 2016.04.13 BONFIGLIOLI RIDUTTORI

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AI summary

A reducer (10) having : - a central electric motor (20); - two wheel hubs ((MZ1)(MZ2)); each hub ((MZ1)(MZ2)) having a respective epicyclic reduction gear ((RR1)(RR2)); - a differential assembly (30); and - a brake assembly (40). The central electric motor (20) separates the differential assembly (30) from the brake assembly (40). And the brake assembly (40) in turn has : - an instantaneous brake piston (42); - a first set (43) of outer disks integral with a box ((BX2)); - a second set (44) of inner disks integral with a sleeve (45); the second set (44) of disks alternating with the first set (43) of disks; - a third set (46) of disks integral with the sun gear ((SN2)) of the epicyclic reduction gear ((RR2)); - a fourth set (47) of disks projecting inwards of the sleeve (45) and alternating with the third set (46) of disks; and -a stop (48) integral with the box ((BX2)).