Variable-Damping Belt Tensioner for Hybrid Starter Generators

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Solution Overview

Problem

Belt tensioning devices in hybrid vehicles with starter generators face challenges in maintaining optimal damping properties across varying operating conditions, leading to potential overshooting and increased fuel consumption due to varying strand forces and vibrations.

Innovation Solution

A belt tensioning device with a damping system that adjusts damping moments based on the rotational position and direction of the tensioning arm, utilizing a radially resilient spring element and varying coefficients of friction over the circumference of the bearing surfaces to provide adaptive damping, minimizing torque in normal operation and increasing damping during starting or boost modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If constant damping is provided in the belt tensioning device, then vibrations are suppressed, but fuel consumption increases due to continuous drag torque

Engineering Contradiction:
Improvevibration suppressionVSAvoidfuel consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the damping torque variable rather than constant. The damping torque adapts dynamically based on the operational state of the starter generator, being higher during starting operations to suppress vibrations and lower during normal operation to reduce fuel consumption. This is achieved through the spring element and friction lining combination that automatically adjusts damping based on operational conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of damping torque from constant to variable. By using a spring element that can be preloaded to different extents and friction linings with varying friction coefficients, the damping torque parameter is adjusted according to operational requirements, allowing optimization between vibration suppression and energy efficiency.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If high damping torque is applied continuously, then overshooting is prevented, but drag torque increases and fuel consumption rises

Engineering Contradiction:
Improveovershoot preventionVSAvoiddrag torque
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The damping torque is made dynamic, applying high values only when needed during starting operations to prevent overshooting, and reducing to low values during normal operation to minimize drag torque. The spring element's preload and the friction lining engagement automatically adjust the damping torque level based on the operational state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The damping torque is applied periodically or conditionally rather than continuously. High damping torque is engaged during starting operations when overshooting risk exists, and disengaged or reduced during normal operation, creating a periodic or conditional action pattern that matches operational requirements.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If simple damping structures are used, then device complexity is reduced, but damping effectiveness varies under different operating conditions

Engineering Contradiction:
Improvedamping structure complexityVSAvoiddamping adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes physical parameters of the damping structure, specifically using a spring element with variable preload and friction linings with different friction coefficients. This allows the damping characteristics to adapt to different operating conditions without requiring complex active control systems, maintaining relatively simple structure while achieving adaptability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The damping structure uses composite functionality by combining a spring element (providing elastic force) with friction linings (providing friction-based damping). This composite approach allows the system to achieve adaptive damping characteristics through the interaction of different mechanical principles, balancing structural simplicity with operational versatility.

Inventive Principle:
Principle #40Composite materials

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 adaptive damping system effectively prevents overshooting, reduces fuel consumption by minimizing drag torque, and maintains optimal belt tensioning across different operating conditions, ensuring efficient energy transfer and reduced vibrations.

Implementation Method 1

a radially resilient spring element (31) is seated in the recess (30) and is resiliently supported radially between the bearing sleeve (26) and the damping plate (32)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The damping means (33) generate, when the first tensioning arm (13) pivots relative to the base body (11), a damping moment which varies depending on the rotational position of the first tensioning arm (13)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3943778B1Belt tensioning device and belt drive comprising such a belt tensioning device
Publication Date: 2024.08.07 MUHR UND BENNDER KG
  • EP3943778B1 patent drawingFigure 1
  • EP3943778B1 patent drawingFigure 2~5
  • EP3943778B1 patent drawingFigure 6

AI summary

Belt tensioning device (1) comprising: a base body (11), a first tensioning arm (13) pivotably mounted on the base body (11) about a first pivot axis (S1) and having a rotatable first tensioning roller (8), a second tensioning arm (14) pivotally mounted relative to the base body (11) about a second pivot axis (S2) and having a rotatable second tensioning roller (9), a spring arrangement (15) arranged between the first tensioning arm (13) and the second tensioning arm (14) and by means of which the first tensioning arm (13) and the second tensioning arm (14) are resiliently supported against each other in the circumferential direction; damping means (33) effectively arranged between the base body (11) and the first tensioning arm (13) to dampen a relative rotational movement between the first tensioning arm (13) and the base body (11);wherein the damping means (33) generate a varying damping moment M when the first clamping arm (13) pivots relative to the base body (11), the damping moment depending on the rotational position and/or direction of rotation of the first clamping arm (13) relative to the base body (11).