Torsional Viscous Damper With Single-Weld Half-Shell Structure

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Solution Overview

Problem

Torsional viscous dampers for internal combustion engines face weaknesses due to axial stresses from weldings, leading to unbalanced structures and reduced resistance to high-speed and axial acceleration, particularly in high-performance engines, where maximum damping is desired while minimizing weight and cost.

Innovation Solution

A torsional viscous damper design featuring two half-shells with a single angular welding at the free radial end, eliminating the weak point of radially inner weldings and enhancing axial stress resistance, combined with a sealing ring and complementary flanges for improved structural balance and fluid sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two axial weldings are used to couple the lid to the casing, then the chamber is sealed, but the structural strength and resistance to axial stress are compromised

Engineering Contradiction:

Improveaxial stress resistanceVSAvoidwelding strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The single welding is segmented into two portions: a first portion extending in the radial direction to provide strong stress resistance, and a second portion extending in the axial direction to provide sealing. This segmentation allows each portion to optimize for its specific function while working together as a unified joint.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The welding transitions from being purely axial (in the previous design) to having a radial component. By adding the radial dimension to the welding orientation, the design achieves superior axial stress resistance while maintaining sealing through the combined radial-axial welding geometry.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the lid and casing have different structural features, then they can be easily manufactured, but the structure becomes unbalanced and prone to vibrations

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstructural balance

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The half-shells are provided with localized structural features (protrusions and recesses) at specific positions to achieve both manufacturing ease and structural balance. The protrusion on one half-shell and the corresponding recess on the other allow for simple assembly while creating a balanced, vibration-resistant structure.

Inventive Principle:

Principle #3Local quality

3Reliability

If multiple weldings are used to seal the chamber, then sealing is improved, but the number of weak points increases

Engineering Contradiction:

Improvesealing reliabilityVSAvoidwelding complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 design significantly improves axial stress resistance, extends the service life of the damper, balances structural stresses, reduces production costs and weight, and achieves maximum damping performance without compromising high-speed and axial acceleration capabilities.

Implementation Method 1

a bath of viscous damping fluid, normally based on silicone. The kinetic energy produced by these torsional vibrations causes the inertial mass, which is contained in the chamber defined by the casing closed by the lid, to resonate. This causes the movement of the inertial mass inside the chamber. The kinetic energy is, thus, transformed into heat via friction and, therefore, dissipated.

Methodology Applied

Scientific EffectViscous damping: Viscous Damping

Implementation Method 2

The half-shells are fixed to one another by means of a single welding, which extends angularly about the axis (A) of the damper, in particular at the free radial end of the half-shells

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentEP4261432B1Improved torsional viscous damper

Publication Date: 2025.01.15 AGLA POWER TRANSMISSION

Figure 1
Figure 2

AI summary

A torsional viscous damper (1) is described for damping torsional vibrations transmitted by a shaft (3) of an engine, the damper (1) has a central rotation axis (A) and comprises: a casing (4) and a lid (5) coupled together for delimiting a closed chamber (6), annular with respect to the central axis (A) and containing a viscous damping fluid; and an inertial mass (7) housed in the chamber (6) so as to be immersed in the viscous fluid; the damper (1) comprises a pair of half-shells (4, 5), a first half-shell (4) defining the casing and a second half-shell (5) defining the lid, each half-shell (4 , 5) defining part of said chamber (6) and part of an axial hub (2) configured to be engaged by said shaft (3), the half-shells (4, 5) are axially coupled to one another for defining, together, said chamber (6) and said hub (2), the half-shells (4, 5) are fixed to each other by means of a single welding (8) which extends angularly about the central axis (A).