Planetary Vehicle Drivetrain for Seamless Ratio Shifting

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Solution Overview

Problem

Existing vehicle transmissions experience uncomfortable traction force interruptions during gear shifts, and alternative solutions like CVT, dual clutch, and hydrodynamic torque converters have limitations such as restricted power transmission, high structural complexity, or significant losses.

Innovation Solution

A drive train with a planetary gear train that allows stepless adjustment of the translation ratio between the primary input shaft and output shaft, utilizing a secondary input shaft's rotation speed to set the translation ratio, and incorporating intermediate elements like gear stages and clutches for compactness and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If selectable gear mechanisms are used to change translation ratio, then the translation ratio can be adjusted, but traction force is interrupted during shift process

Engineering Contradiction:

Improvetranslation ratio adjustmentVSAvoidtraction force continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The planetary gear mechanism enables dynamic adjustment of the translation ratio by varying the rotation speed of the secondary input shaft while maintaining continuous power flow. The system transitions from static gear ratios to dynamic ratio adjustment, allowing the translation ratio to change smoothly without interrupting traction force delivery to the output shaft.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The planetary gear train acts as an intermediary mechanism between the primary and secondary input shafts, enabling continuous power transmission while adjusting the translation ratio. The planetary gears mediate the power flow, allowing ratio changes without the complete disengagement and re-engagement required in conventional gear mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If CVT transmissions are used for stepless adjustment, then translation ratio can be adjusted continuously, but transmissible power is restricted due to friction

Engineering Contradiction:

Improvetranslation ratio adjustmentVSAvoidtransmissible power

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The invention replaces the friction-based mechanical contact of CVT systems with a planetary gear mechanism that transmits power through rigid gear engagement. This substitution eliminates the friction limitation, allowing continuous translation ratio adjustment while maintaining high transmissible power capability through positive gear engagement rather than frictional contact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If dual clutch transmission is used for stepless adjustment, then translation ratio can be adjusted continuously, but structural complexity increases

Engineering Contradiction:

Improvetranslation ratio adjustmentVSAvoidstructural complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The planetary gear mechanism serves multiple functions simultaneously: it provides continuous translation ratio adjustment, maintains structural compactness, and enables power splitting between primary and secondary input shafts. This multi-functionality replaces the need for complex dual clutch mechanisms, achieving stepless adjustment with simpler architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If transmission with hydrodynamic torque converter is used, then traction force interruption is reduced, but energy losses increase

Engineering Contradiction:

Improvetraction force continuityVSAvoidenergy losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention replaces the hydrodynamic torque converter with a planetary gear mechanism that achieves continuous power transmission through rigid mechanical engagement. This substitution eliminates the hydrodynamic losses inherent in fluid-based torque transmission while maintaining continuous traction force delivery, resulting in higher efficiency without sacrificing reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12012004B2Drive train for a vehicle

Publication Date: 2024.06.18 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH

AI summary

A drive train for a vehicle includes at least one transmission having a primary input shaft designed to be connected to a primary drive, a secondary input shaft designed to be connected to a secondary drive, an output shaft designed to output power that has been introduced into the at least one transmission by the primary input shaft, and a planetary gearbox designed to continuously variably set a transmission ratio between the primary input shaft and the output shaft on the basis of the rotational speed of the secondary input shaft. The invention further relates to a vehicle having a drive train of this type, to a method for controlling a drive train of this type, and to a computer program product.