Clutch Actuation Assembly with Nested Automatic Actuator

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Solution Overview

Problem

Conventional clutch actuation arrangements for manual transmissions do not allow for comfortable shifting while still enabling driver intervention, as they either require manual operation or rely solely on automatic systems, lacking flexibility and efficiency.

Innovation Solution

A clutch actuation arrangement with a master cylinder, a slave cylinder, and an intermediate cylinder connected hydraulically, featuring an automatic actuator that can actuate the clutch automatically or manually, allowing for seamless integration with existing designs and enabling both automatic and manual operation modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If an automatic actuator is added to enable automatic clutch actuation, then driving comfort and automation are improved, but device complexity increases

Engineering Contradiction:
Improveautomatic clutch actuationVSAvoidclutch actuation arrangement
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The automatic actuator is arranged concentrically inside the ring cylinder, with the ring piston guided in the ring cylinder and capable of engaging on the intermediate piston. This nested configuration allows the automatic actuation system to be integrated within the existing hydraulic clutch actuation arrangement without requiring separate external components, thereby improving automation while minimizing the increase in device complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

An intermediate cylinder with an intermediate piston is introduced as a mediator between the master cylinder and the slave cylinder. The automatic actuator acts on the intermediate piston, which then transmits force through the hydraulic medium to the slave cylinder. This intermediary mechanism enables automatic clutch actuation while maintaining compatibility with the existing master-slave cylinder hydraulic system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If an intermediate cylinder and automatic actuator are integrated concentrically, then space utilization and compactness are improved, but manufacturing complexity increases

Engineering Contradiction:
Improveactuator assembly volumeVSAvoidconcentric integration
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The automatic actuator and ring cylinder are arranged concentrically around the intermediate piston, creating a compact nested structure where the ring piston can engage on the intermediate piston. This concentric integration maximizes space utilization by utilizing the radial space around the intermediate piston, reducing the overall volume required for the actuator assembly

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The intermediate piston serves multiple functions: it is actuated by the master cylinder through hydraulic pressure, it can be engaged by the ring piston of the automatic actuator, and it transmits force to the slave cylinder. This multi-functionality reduces the need for separate components, simplifying the overall manufacturing process despite the concentric integration

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

3Power

If the automatic actuator acts directly on the intermediate piston, then actuation efficiency is improved, but the risk of interfering with manual operation increases

Engineering Contradiction:
Improveactuation force transmissionVSAvoidmanual clutch operation
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The system dynamically switches between manual and automatic actuation modes. When the driver operates the clutch pedal, the master piston moves and increases hydraulic pressure in the intermediate cylinder, which moves the intermediate piston. The automatic actuator is designed to disengage from the intermediate piston during manual operation, allowing pure manual actuation. When automatic mode is activated, the automatic actuator engages with the intermediate piston to provide assisted or automatic clutch actuation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The intermediate piston acts as a mediator that can receive force from either the master cylinder (manual operation) or the automatic actuator (automatic operation). The hydraulic coupling between the master cylinder and intermediate piston ensures that manual operation through the clutch pedal is transmitted effectively, while the automatic actuator can independently actuate the intermediate piston when needed, without permanently interfering with manual operation

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This solution provides a compact, efficient, and comfortable shifting experience by allowing automatic actuation in certain conditions while allowing the driver to manually intervene, maintaining the flexibility of manual transmission operation without significant efficiency losses.

Implementation Method 1

a master cylinder that can be foot-operated via a clutch pedal for applying hydraulic and/or pneumatic pressure

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

The servo cylinder contains at least one piston that is used to generate an auxiliary force

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

a slave cylinder that is hydraulically connected to the master cylinder for opening and/or or closing the clutch

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2937589B1Clutch actuation assembly
Publication Date: 2018.01.10 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2937589B1 patent drawingFigure 1~2

AI summary

Clutch actuation arrangement for actuating a clutch for coupling a drive shaft of a motor vehicle engine with at least one transmission input shaft of a motor vehicle transmission, provided with a master cylinder (12) that can be foot-operated via a clutch pedal for applying hydraulic and/or pneumatic pressure, a slave cylinder (16) hydraulically connected to the master cylinder for opening and/or closing the clutch, an intermediate cylinder (20) hydraulically arranged between the master cylinder and the slave cylinder for applying hydraulic and/or pneumatic actuation pressure for actuating the clutch, an intermediate piston (22) guided in the intermediate cylinder (20), wherein the master cylinder hydraulically acts on the intermediate piston, and an automatic actuator (32) acting on the intermediate piston for displacing the intermediate piston in the intermediate cylinder.If the driver desires comfortable shifting without pressing the clutch pedal, the automatic actuator can automatically engage the clutch and, if necessary, initiate a shifting process, while simultaneously retaining the option of manually engaging the clutch pedal independently of the automatic actuator. Thus, a comfortable shifting of a manual transmission is made possible through a structurally simple arrangement of the intermediate cylinder and the automatic actuator, without depriving the driver of the ability to intervene.