Hybrid Powershift Transmission with Claw Clutch Mode Switching

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Solution Overview

Problem

Hybrid drive systems in vehicles, particularly those with multiple electric machines and internal combustion engines, face challenges in optimizing power flow and efficiency due to complex transmission designs and high installation space requirements, leading to inefficiencies and increased mechanical complexity.

Innovation Solution

A hybrid drive system with a powershift transmission that utilizes two partial transmissions, including a power-split transmission and a spur gear secondary shaft transmission, connected via a claw switching element with multiple switching positions, allowing for flexible power distribution and efficient energy recovery without the need for separate clutches, enabling seamless gear changes and operation modes without traction interruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple separate clutches are used to control different switching positions in the transmission, then the ability to achieve various operating modes (power split, electric drive, generator operation) is improved, but the mechanical complexity and number of components increase significantly

Engineering Contradiction:
Improveoperating mode flexibilityVSAvoidtransmission component count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The claw clutch is designed as a universal coupling element that can assume multiple switching positions (first, second, third positions) to control different operating modes. Instead of using separate clutches for each mode, this single multi-functional component replaces multiple specialized clutches, thereby reducing mechanical complexity while maintaining the ability to achieve power split, electric drive, and generator operation modes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functions of multiple separate clutches into a single claw clutch component. By combining the switching control for different transmission modes into one integrated element, the design reduces the total number of components and simplifies the transmission structure while preserving all necessary operating capabilities.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a complex transmission design with multiple clutches and shafts is used to enable flexible power distribution, then the ability to optimize power flow is improved, but the installation space requirements increase

Engineering Contradiction:
Improvepower flow control capabilityVSAvoidtransmission installation space
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The invention consolidates multiple transmission functions into a compact arrangement where the claw clutch integrates multiple switching positions and control functions. This merging of functions into a single integrated component reduces the overall footprint and installation space requirements compared to designs using multiple separate clutches and shafts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The claw clutch serves multiple functions simultaneously - it can couple and decouple different shafts, control power flow distribution, and enable various operating modes all through a single component. This multi-functionality eliminates the need for additional separate components that would increase installation space.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If separate clutches are used for each switching position to ensure reliable mode switching, then the reliability of mode transitions is improved, but the mechanical effort and overall system complexity increase

Engineering Contradiction:
Improvemode switching reliabilityVSAvoidmechanical system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The claw clutch is designed as a reliable universal switching element that can assume distinct switching positions (first, second, third positions) for different operating modes. The positive engagement mechanism of the claw clutch ensures reliable coupling and decoupling in each position while maintaining a simpler overall system compared to multiple separate clutches.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3244097B1Hybrid power train with powershift transmission and method of switching such a transmission in the hybrid power train
Publication Date: 2023.11.08 HOFER POWERTRAIN INNOVATION GMBH
  • EP3244097B1 patent drawingFigure 1
  • EP3244097B1 patent drawingFigure 2
  • EP3244097B1 patent drawingFigure 3

AI summary

The present invention deals with the design of a hybrid drive or a drive train that is equipped with different drive motors, preferably different energy types. Such a hybrid drive creates the possibility of using different drive energy carriers. The various drive sources or drive motors are connected to one another via a gear. The transmission with its switching positions and switching variants makes it possible to bring one or the other drive motor alone or in combination with other drive motors in terms of torque directly or indirectly or directly or translated to the driven road wheels. Advantageously, the transmission can also be shifted under load. Shift changes can be carried out even under load.