Hybrid Transmission Clutch Layout for Compact Case Packaging

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Solution Overview

Problem

The incorporation of an actuator and an electric motor into a hybrid drive module increases the thickness and size of the case, necessitating a solution to restrain the growth in dimensions.

Innovation Solution

A power transmission device with a case member that accommodates a clutch, reduction gear pair, and release member, featuring a bulge portion that radially extends to house part of the release member, with the rotating electric machine on one side and the actuator on the opposite side, thereby optimizing space utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the actuator and the electric motor are incorporated into the hybrid drive module, then the clutch can be operated to connect and disconnect power transmission, but the thickness of the case and the overall size of the hybrid drive module increase

Engineering Contradiction:
Improveclutch operationVSAvoidcase thickness
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent applies dimensional redistribution by extending the case in the radial direction (width) rather than increasing thickness in the axial direction. The actuator is positioned radially outward from the clutch assembly, allowing the clutch operation function to be achieved while maintaining compact axial thickness. This dimensional shift resolves the contradiction between operational capability and case thickness.

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

Solution Approach 2:

The actuator is nested within the hybrid drive module assembly, with its operating mechanism integrated into the existing clutch housing structure. The actuator rod connects directly to the clutch release mechanism through the case wall, allowing compact integration that minimizes the required case thickness while maintaining full operational functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the actuator and the electric motor are incorporated into the hybrid drive module, then the clutch can be operated to connect and disconnect power transmission, but the hybrid drive module increases in size

Engineering Contradiction:
Improveclutch operationVSAvoidmodule area
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The design redistributes spatial requirements by utilizing the radial dimension for actuator placement rather than expanding the axial or lateral dimensions of the module. This allows the clutch operation function to be integrated without increasing the overall footprint area of the hybrid drive module.

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

Solution Approach 2:

The actuator mechanism is merged with the existing clutch housing and case structure, sharing common mounting surfaces and support elements. This integration eliminates the need for separate actuator housings and reduces the overall module area by consolidating multiple functions into a compact unified assembly.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4678439A1Power transmission device for hybrid vehicle
Publication Date: 2026.01.14 SUZUKI MOTOR CORP
  • EP4678439A1 patent drawingFigure 1
  • EP4678439A1 patent drawingFigure 2
  • EP4678439A1 patent drawingFigure 3

AI summary

[Problem to be solved] There is provided a power transmission device (4) for a hybrid vehicle that can restrain thickness of a case body accommodating a clutch (26), a release member (36), and a reduction gear pair (28, 35) from increasing and restrain the power transmission device (4) from increasing in size. [Solution] A case member (21) of a power transmission device (4) has a case body portion (21A) that accommodates a damper (22), a wet clutch (26), a drive gear (35), a driven gear (28), and a release mechanism (36), and a bulge portion (21B) that bulges outward in a radial direction from the case body portion (21A) and accommodates a driven plate (37A) that is a part of the release mechanism (36), a motor generator (2) is disposed on one side of the bulge portion (21B) outside the case member (21), and an actuator (motor (41)) is disposed on the other side of the bulge portion (21B) on an opposite side to the motor generator (2).