Hybrid Power Distribution Shaft Layout for Compact, Low-Loss Drivetrains

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Solution Overview

Problem

Hybrid electric vehicles face a contradiction between transmission efficiency and spatial arrangement, with existing designs often compromising on either efficiency or compactness due to the spatial constraints and complexity of power transmission systems.

Innovation Solution

A hybrid power-driven system with independent motor and engine modules, featuring a power distribution shaft that allows direct transmission between the motor and the transmission mechanism or main reducer, minimizing the need for intermediate gears and optimizing spatial usage, enabling efficient power distribution and compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the motor is integrated with the transmission mechanism through shared shafts and gears, then the spatial arrangement is compact, but the transmission efficiency decreases due to overlapping transmission paths and increased mechanical losses

Engineering Contradiction:
Improvespatial arrangementVSAvoidtransmission efficiency
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The power transmission system is segmented into two independent modules: the engine transmission mechanism and the motor power distribution mechanism. Each module has its own dedicated transmission path, avoiding overlapping and reducing mechanical losses. The motor power distribution mechanism includes a power distribution shaft, mode selection apparatus, and transmission apparatus that independently transmit motor power without interfering with the engine transmission path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The motor power distribution mechanism is extracted as a separate module from the traditional integrated transmission system. The power distribution shaft and associated gears are taken out as independent components that can selectively connect to either the input shaft or main reducer, allowing the motor to operate independently without being constrained by the engine transmission path.

Inventive Principle:
Principle #2Taking out (Extraction)

2Loss of energy

If the motor power distribution mechanism uses a separate power distribution shaft independent from both the transmission mechanism and motor, then the transmission paths have low overlap and efficiency improves, but the device complexity increases

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The power distribution shaft serves multiple functions: it transmits motor power to the input shaft during engine-start modes, transmits motor power to the main reducer during motor-driven modes, and enables selective switching between different operating modes through the mode selection apparatus. This multi-functionality justifies the added complexity by providing versatile power transmission capabilities.

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

Solution Approach 2:

The system employs a dynamic mode selection apparatus that can selectively connect the power distribution shaft to different components based on operating conditions. The synchronizers and shifting mechanisms allow the system to dynamically switch between first mode (motor to input shaft) and second mode (motor to main reducer), optimizing performance for different driving scenarios.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If direct transmission paths are used between the motor and both the input shaft and main reducer, then the transmission path length is minimized and efficiency is maximized, but the spatial arrangement becomes more challenging

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidspatial arrangement
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The power distribution shaft is arranged in a spatial configuration that allows direct meshing with both the input shaft gear and main reducer gear through three-dimensional positioning. The first gear and second gear on the power distribution shaft are coaxially disposed and directly meshed with their respective targets, utilizing radial and axial spaces efficiently to achieve direct transmission paths without excessive length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Adaptability or versatility

If the hybrid power-driven system implements mode switching between motor-to-input-shaft and motor-to-main-reducer configurations, then the adaptability improves, but the control complexity increases

Engineering Contradiction:
Improvemode switching capabilityVSAvoidcontrol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The mode selection apparatus acts as an intermediary control mechanism between the motor power distribution mechanism and the two possible power transmission paths. It includes synchronizers and shifting mechanisms that mediate the connection state, automatically engaging or disengaging the appropriate transmission path based on the selected mode, thereby simplifying the control logic despite the dual-mode capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3868587B1Hybrid power drive system and vehicle
Publication Date: 2024.12.04 BYD CO LTD
  • EP3868587B1 patent drawingFigure 1
  • EP3868587B1 patent drawingFigure 2
  • EP3868587B1 patent drawingFigure 3

AI summary

A hybrid power-driven system and a vehicle are provided. The hybrid power-driven system includes an engine, a transmission, and a motor power apparatus. The transmission includes a transmission mechanism and a main reducer. The motor power apparatus includes a motor and a power distribution mechanism. The power distribution mechanism includes a power distribution shaft, a mode selection apparatus, a first transmission apparatus, and a second transmission apparatus. The power distribution shaft is disposed independently from the transmission mechanism, and the power distribution shaft is disposed independently from the motor. A motor driven gear configured to receive power of the motor is disposed on the power distribution shaft.