Switchable Drag Lever Alignment via Segment Collar

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing drag levers for valve timing mechanisms in internal combustion engines are excessively wide and deep due to transverse bracket-like stops, leading to high material loading and alignment issues, which hinder coupling and freedom of movement.

Innovation Solution

The introduction of a segment-like collar on the outer lever that contacts the inner lever's arm, eliminating the need for a transverse bracket and allowing for alignment and reduced friction, enabling a narrower and more efficient drag lever design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a transverse bracket-like stop is used to align the inner lever, then alignment of receptacles is achieved, but the drag lever becomes excessively wide and deep

Engineering Contradiction:

Improvealignment of receptaclesVSAvoiddrag lever width and depth

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

Instead of using a transverse bracket extending outward from the outer lever to engage the inner lever, the invention inverts the approach by providing stop faces directly on the inner lever's arm that engage with the outer lever's side walls. This eliminates the need for protruding bracket structures and achieves alignment without increasing drag lever dimensions.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention extracts and eliminates the transverse bracket-like stop structure from the design. By removing this unnecessary intermediate component and directly engaging the inner lever's stop faces with the outer lever's side walls, the design achieves alignment functionality without the volumetric penalty of bracket structures.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If a transverse bracket is used for alignment, then coupling position is fixed, but freedom of movement in the cylinder head region is restricted

Engineering Contradiction:

Improvealignment of coupling meansVSAvoidfreedom of movement

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention inverts the engagement direction by having the inner lever's stop faces engage with the outer lever's side walls rather than having the outer lever's bracket engage the inner lever from above. This allows the inner lever's mating running face to move freely in the cam base circle while maintaining proper alignment through the stop faces.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention segments the alignment function from the support function. The stop faces on the inner lever's arm provide alignment without providing support, allowing the inner lever to maintain freedom of movement in the cam base circle while still achieving precise receptacle alignment.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If the drag lever is made wider to accommodate the bracket, then alignment is improved, but material loading increases

Engineering Contradiction:

Improvealignment precisionVSAvoidmaterial loading

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

The invention inverts the structural approach by eliminating the need for a wide bracket structure. The stop faces are integrated into the inner lever's arm geometry, allowing alignment to be achieved without increasing the overall drag lever width, thereby reducing material loading and Hertzian stress.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the geometric parameters of the alignment structure by replacing a wide, deep bracket with compact stop faces that engage horizontally. This parameter change reduces the volume and mass of material required while maintaining alignment precision, thereby reducing material loading and stress.

Inventive Principle:

Principle #35Parameter changes

4Manufacturing precision

If the drag lever is made deeper to accommodate the bracket engagement, then alignment is achieved, but base circle friction increases

Engineering Contradiction:

Improvealignment of receptaclesVSAvoidbase circle friction

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention inverts the engagement geometry by having stop faces engage horizontally rather than vertically. This eliminates the need for increased lever depth, allowing the inner lever's mating running face to move freely in the cam base circle without restriction, thereby reducing base circle friction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7240652B2Switchable drag lever of a valve timing mechanism of an internal combustion engine

Publication Date: 2007.07.10 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A switchable drag lever (1) of a valve timing mechanism of an internal combustion engine is proposed, having an outer lever (3) and an inner lever (4) which is arranged between the said outer lever (3). The drag lever (1) has a rest (7) for a gas exchange valve on an underside (5) at one end (6), and a pivoting bearing (9) for a supporting element on an underside (5) at the other end (8). The levers (3, 4) extend at one end (6) on a common pin (10). Receptacles (10a, 10b) for coupling means are provided which extend longitudinally at the end (8) facing away from the pin (10) and are aligned with respect to one another in the cam base circle. The side walls (2) of the outer lever (3) have contact faces (12) for lifting cams on their upper sides (11). A segment-like collar (13) protrudes inwards from each upper side (11), which segment-like collar (13) forms a structural unit with the respective contact face (12), the corresponding underside (14) of the collar (13) bearing against a complementary stop face (15) of an upper side (16) of the adjacent arm (2a) of the inner lever (4) in the coupling case. Alignment of the receptacles (10a, 10b) is therefore provided in a simple way for the coupling case.