Tiltable Transmission Element for Friction Clutch Spindle Drive

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Solution Overview

Problem

In spindle drives, the tilting of the spindle nut due to increased friction leads to blocking of the adjustment device, and existing travel-controlled adjustment devices fail to maintain constant engagement and actuation paths as the friction lining wears, causing inefficiencies and potential unintended adjustments.

Innovation Solution

A spindle drive with a tiltable sheet metal transmission element that centrally applies force to the spindle nut, preventing tilting and maintaining constant engagement and actuation paths by compensating for relative movements and height changes through rotational adjustment of the adjustment ring, ensuring stable transmission force and preventing unintended adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the spindle nut engages directly with the adjusting ring, then the transmission force can be applied, but the spindle nut tilts due to increased friction, leading to blocking of the adjustment device

Engineering Contradiction:
Improvetransmission forceVSAvoidblocking of adjustment device
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

A transmission element is introduced as an intermediary component between the spindle nut and the adjusting ring. This transmission element receives the transmission force from the spindle nut and transfers it to the adjusting ring, preventing direct engagement that causes tilting. The transmission element acts as a mediator that decouples the force transmission path from the tilting mechanism, thereby maintaining reliability while preserving force transmission capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If the friction lining thickness decreases, then wear occurs, but the engagement path and actuation path become non-constant, causing inefficiencies

Engineering Contradiction:
Improveservice life of friction liningVSAvoidengagement path constancy
Core Design Contradiction:
Duration of action of moving objectVSProductivity

Solution Approach 1:

The transmission element is designed to be tiltable, allowing it to dynamically adapt its position as the friction lining wears and the adjusting ring rotates. This dynamic capability enables the system to maintain constant engagement and actuation paths throughout the service life of the friction lining, preventing inefficiencies while accommodating the natural wear process over time.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the spindle nut is translationally movable by worm drive, then displacement control is achieved, but friction increases and causes tilting

Engineering Contradiction:
Improvedisplacement controlVSAvoidfriction between spindle nut and worm drive
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The transmission element serves as an intermediary that receives the displacement-controlled force from the spindle nut and transfers it to the adjusting ring. By introducing this intermediate component, the system maintains the ease of displacement control provided by the worm drive while reducing the harmful effects of friction-induced tilting, as the transmission element absorbs and redistributes the forces more effectively.

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

The solution effectively reduces friction between the spindle nut and worm drive, prevents tilting, and maintains constant engagement and actuation paths, ensuring reliable and efficient operation even with wear of the friction lining, suitable for high-contact-pressure applications and space-constrained environments.

Implementation Method 1

a spindle shaft with a worm drive; a spindle nut that is translationally movable by means of the worm drive of the spindle shaft as a result of a rotation of the spindle shaft

Methodology Applied
Scientific EffectWorm drive: Worm Drive

Implementation Method 2

a transmission element designed to transmit the translational movement of the spindle nut to an adjusting ring rotatable about an axis of rotation oriented transversely to the spindle shaft. The spindle drive is characterized primarily by the fact that the transmission element comprises a sheet metal element that can be tilted about the axis of rotation, via which, in the assembly, the transmission force from the spindle nut to the adjusting ring can be centrally introduced onto the spindle nut

Methodology Applied
Scientific EffectMechanical force transmission through tilting: Mechanical Force

Implementation Method 3

a drive pinion for driving the spindle shaft; a drive pawl attachable to a coupling cover for the displacement-controlled driving of the drive pinion

Methodology Applied
Scientific EffectPawl and pinion engagement: Gear

Data Source

PatentEP3123048B1Path-controlled adjusting device for a friction clutch
Publication Date: 2019.10.23 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3123048B1 patent drawingFigure 1~2
  • EP3123048B1 patent drawingFigure 3~5
  • EP3123048B1 patent drawingFigure 6

AI summary

The invention relates to a spindle drive (1) for a path-controlled adjusting device, which has at least the following components: a spindle shaft (3) having a worm gear drive (4); a spindle nut (5), which is translationally movable by means of the worm gear drive of the spindle shaft as a result of a torsion of the spindle shaft; a drive pinion (6) for driving the spindle shaft; a drive pawl (8), which is fastenable to a coupling cover (7), for path-controlled driving of the drive pawl; a receptacle (9) for the spindle shaft, which axially fastens the spindle shaft; and a transfer element (10) which is designed to transfer the translational movement of the spindle nut to an adjusting ring, which is rotatable about a rotation axis aligned crosswise to the spindle shaft, wherein the transfer element comprises a plate element (13), which is tiltable around the rotation axis and via which, in assembly, the transfer force from the spindle nut on the adjusting ring can be applied centrally on the spindle nut. The transfer element according to the invention ensures an always central force application into a spindle nut, thus preventing a blocking of the adjusting device.