Hybrid Vehicle Gear Layout for Input Gear Lubrication

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Solution Overview

Problem

In hybrid vehicles, the position of the input gear above the lubricating oil level creates difficulties in effectively lubricating the gear due to upward thrusting of lubricating oil by the intermediate gear, leading to inadequate lubricity.

Innovation Solution

The design positions the intermediate gear lower than the input gear, with an oil reservoir and passage system to direct upward-thrust lubricating oil to the input gear, ensuring efficient lubrication without the need for a separate lubricating oil pump.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the input gear is positioned higher to accommodate high-volume internal combustion engine drive force, then the engine power transmission capability is improved, but the lubricating oil supply to the input gear becomes insufficient

Engineering Contradiction:

Improveengine power transmission capabilityVSAvoidlubricating oil supply reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

Instead of positioning the input gear higher than the intermediate gear (conventional arrangement), the patent inverts the vertical positions so that the intermediate gear is higher than the input gear. This inversion allows the intermediate gear to effectively thrust lubricating oil upward to the input gear, solving the lubrication problem while maintaining high power transmission capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces an oil reservoir positioned between the intermediate gear and the input gear as an intermediary structure. This oil reservoir collects and stores the lubricating oil thrust upward by the intermediate gear, then supplies it to the input gear, ensuring reliable lubrication for the high-positioned input gear.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the intermediate gear is positioned higher than the input gear, then the structural arrangement is simplified, but the lubricating oil cannot be effectively supplied to the input gear

Engineering Contradiction:

Improvetransmission device structureVSAvoidinput gear lubrication

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies inversion by positioning the intermediate gear higher than the input gear, which is the opposite of the conventional arrangement. This inverted configuration enables the intermediate gear to naturally thrust lubricating oil upward to the input gear through its rotation, achieving effective lubrication while maintaining structural simplicity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The intermediate gear serves a dual function: it transmits power and simultaneously thrusts lubricating oil upward to the input gear through its rotation. This self-service mechanism eliminates the need for separate lubrication pumps or complex oil supply systems, achieving reliable lubrication through the gear's own rotational motion.

Inventive Principle:

Principle #25Self-service

3Volume of moving object

If the input gear is positioned above the oil level, then space utilization is improved, but gear lubricity deteriorates leading to increased friction and heat

Engineering Contradiction:

Improvetransmission device space utilizationVSAvoidfriction and heat generation

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the vertical positioning relationship, placing the intermediate gear above the input gear. This inversion enables the intermediate gear to thrust lubricating oil upward to the input gear during rotation, ensuring the input gear receives adequate lubrication even though it is positioned above the main oil level, thereby reducing friction and heat generation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The oil reservoir acts as an intermediary that collects lubricating oil from the intermediate gear's upward thrust and supplies it to the input gear. This intermediary structure ensures continuous lubrication of the high-positioned input gear, preventing metal-to-metal contact and reducing harmful friction and heat generation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration enhances the lubricity of the input gear by effectively supplying lubricating oil, reducing gear rattle and maintaining motive power transmission efficiency while minimizing heat generation and oil agitation.

Implementation Method 1

supplying the lubricating oil is a problem to be addressed... thrusting the lubricating oil upward to lubricate the input gear... lubricating oil that has been thrust upward by the intermediate gear to be supplied to the input gear

Methodology Applied

Scientific EffectHydrodynamic lubrication: Lubrication

Data Source

PatentEP3862206B1Hybrid vehicle

Publication Date: 2024.02.14 NISSAN MOTOR CO LTD

Figure 1
Figure 2~3

AI summary

A rotational center O2 of an intermediate gear 14 (second gear 12a2, internal-combustion-engine final reduction gear 12b) is positioned lower than a straight line L1 that links a rotational center O1 of a first gear 12a1 and a rotational center O3 of a ring gear 10a as seen from a rotational-axis direction of a driveshaft 5.