Integrated Hydraulic Clutch Actuator for Compact Transmission Modules

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Solution Overview

Problem

Existing hydraulic actuators for hybrid drive vehicles have large overall dimensions, particularly in the axial direction, posing challenges for installation in situations with limited space.

Innovation Solution

A compact hydraulic actuator is integrated into the support structure of a transmission module, reducing axial dimensions and eliminating the need for dedicated fixing means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If autonomous hydraulic actuators are used, then the actuator can function independently, but the overall dimensions become large particularly in axial direction

Engineering Contradiction:
Improveindependent functionVSAvoidaxial dimensions
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The actuator is integrated into the support structure by merging the piston chamber with a cavity in the support structure and the piston rod with a protrusion from the support structure. This combining of previously separate components (autonomous actuator and support structure) into a unified integrated assembly achieves space reduction in axial direction while maintaining independent actuation function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support structure serves multiple functions: it provides structural support, houses the piston chamber, and integrates the actuator mounting. The cavity in the support structure is multi-functional, serving both as a structural feature and as the hydraulic chamber for actuator operation. This multi-functionality eliminates the need for separate autonomous actuator housing.

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

2Reliability

If dedicated fixing means are used, then the actuator can be securely mounted, but the installation space requirement increases

Engineering Contradiction:
Improvemounting securityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The fixing means are integrated directly into the support structure rather than being separate components. The piston rod is constrained by a protrusion from the support structure, and the piston chamber is formed within a cavity of the support structure. This integration eliminates dedicated fixing means as separate elements while maintaining secure mounting through the unified structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator components are nested within the support structure. The piston chamber is nested within a cavity of the support structure, and the piston rod is nested within a constrained path defined by a protrusion. This nesting arrangement secures the actuator within the support structure without requiring external fixing means, thereby reducing installation space requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

The integrated actuator allows the module to be housed in spaces with limited axial space, enhancing installation flexibility and reducing overall size.

Implementation Method 1

The hydraulic actuators for known clutches generally consist of an autonomous unit defining an internal chamber into/from which pressurized oil can be supplied/discharged. When the chamber is pressurized, the actuator expands axially so as to provide an axial load which overcomes the force of the clutch spring.

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4081720B1Transmission module provided with a hydraulic actuator
Publication Date: 2025.07.30 PROPULSION SOLUTIONS SRL
  • EP4081720B1 patent drawingFigure 1~2
  • EP4081720B1 patent drawingFigure 3
  • EP4081720B1 patent drawingFigure 4

AI summary

A transmission module (1) for a hybrid drive vehicle configured to be interposed between an internal combustion engine (E) and a transmission (T) of the vehicle, including a tray-like support structure (5) configured to be secured to the engine (E) and defining a housing (22) for a clutch (23) to be interposed between a crankshaft (7) of the internal combustion engine (E) and the said module (1), and an actuator (34) for controlling the clutch (23), wherein the actuator (34) includes an annular chamber (36) provided in the support structure (5) and open towards the housing (22) for the clutch, an annular piston (35) housed in the annular chamber (36) in an axially sliding and angularly fixed way, and a thrust member (46) coupled in a rotationally free manner to the piston (35), coaxial thereto and operable to cooperate with a control member (30) of the clutch (23) under the thrust of the piston (35).