Adjustable Camshaft Assembly with Integrated Latching Mechanism

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Solution Overview

Problem

Existing adjustable camshafts for internal combustion engines face difficulties in assembly, as the locking element and spring element must be pre-installed correctly to avoid blocking and ensure proper latching, and reworking is challenging without disassembling the camshaft. Additionally, the process is prone to errors and distortion due to hardening or surface finishing of the support shaft.

Innovation Solution

The spring element and latching element are integrated into the cam assembly, allowing it to be slid onto the support shaft without prior arrangement, with the locking element and spring element being arranged after assembly, enabling precise prestressing and reworking without disassembly. This design eliminates the need for a receiving bore and ensures a positive-locking geometry between the carrier shaft and cam assembly, preventing distortion during hardening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the locking element and spring element are pre-installed in the support shaft before assembling the cam assembly, then the latching mechanism can function properly, but the assembly process becomes complex and error-prone, and reworking is difficult without disassembly

Engineering Contradiction:
Improvelatching mechanism functionVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent inverts the conventional assembly sequence by placing the locking element and spring element in the cam assembly rather than pre-installing them in the support shaft. This allows the cam assembly to be slid onto the support shaft freely, with the locking mechanism engaging automatically at the correct position, simplifying assembly and enabling easy reworking.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The locking element and spring element are extracted from the support shaft and integrated into the cam assembly. This separation allows the support shaft to be hardened and finished without distortion concerns, while the locking mechanism remains accessible for assembly and reworking.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If a receiving bore is provided in the support shaft for the locking element, then the locking mechanism can be installed, but the bore may be distorted during hardening or surface finishing of the support shaft

Engineering Contradiction:
Improvelocking element installationVSAvoidbore position accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The receiving bore is extracted from the support shaft and relocated to the cam assembly. This eliminates the risk of bore distortion during support shaft hardening or surface finishing, while still providing a proper mounting location for the locking element and spring mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the locking element is spherical to allow easy engagement, then the cam assembly can be pushed onto the support shaft, but the locking element may block the assembly process if not positioned correctly

Engineering Contradiction:
Improvecam assembly installationVSAvoidassembly process
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

A groove structure is introduced as an intermediary feature in the support shaft that guides the spherical locking element into the correct position during assembly. This mediator ensures proper engagement without blocking the assembly process, combining the benefits of spherical geometry with precise positioning.

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 simplifies the assembly process, ensures correct prestressing of the latching element, allows for reworking without disassembly, and prevents distortion during surface finishing, enhancing the reliability and ease of use of the camshaft system.

Implementation Method 1

at least one latching element biased by a spring element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3068983B1Adjustable camshaft
Publication Date: 2018.12.19 THYSSENKRUPP PRESTA TECCENTER AG
  • EP3068983B1 patent drawingFigure 1~4b
  • EP3068983B1 patent drawingFigure 5~7b

AI summary

The present invention relates to an adjustable camshaft (1) for an internal combustion engine having a support shaft (11) which extends in the direction of a rotational axis (10), wherein at least one cam pack (12) having at least one cam element (13) is received on the support shaft (11) such that it can be displaced in the direction of a rotational axis (10), wherein the cam pack (12) can be latched in at least two axial latching positions on the support shaft (11), and wherein at least one latching element (15) which is prestressed by way of a spring element (14) and at least one latching element seat (16) are provided in order to form the latching positions, with the result that the latching element (15) can latch in the latching element seat (16) in the latching positions. According to the invention, the spring element (14) and the latching element (15) which is prestressed by way of it are received in the cam pack (12), and it is provided that the at least one latching element seat (16) is arranged on the support shaft (11).