Leaf Spring Suspension Failure Detection via Wind-Up Path Sensing

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Solution Overview

Problem

Detecting leaf spring failure in vehicle suspension systems is difficult, especially in harsh environments, leading to potential accidents and costly repairs due to undetected damage.

Innovation Solution

A vehicle suspension system with inertial measurement units at the wind-up center of leaf springs to monitor the actual path of deflection, comparing it to a reference path, and generating an alarm if a threshold difference is detected, allowing for early warning and automatic speed reduction or stoppage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If visual inspection methods are used to detect leaf spring failure, then detection can be performed without additional equipment, but detection reliability is poor especially in harsh environments

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces manual visual inspection with an automated sensor-based detection system. Accelerometers and gyroscopes mounted on the vehicle systematically collect data about suspension behavior, eliminating the need for manual inspection and providing reliable detection even in harsh environments where visual inspection fails.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces intermediate sensor components (accelerometers, gyroscopes) that mediate between the leaf spring system and the detection function. These sensors indirectly measure leaf spring status through suspension behavior patterns, providing reliable detection without direct contact with the leaf springs themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If manual inspection is performed by drivers, then no additional detection equipment is needed, but detection precision is insufficient due to driver inability to sense unbalanced vehicle behavior

Engineering Contradiction:
Improvefailure detection precisionVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces human driver sensing capability with electronic sensors. Accelerometers and gyroscopes precisely measure suspension dynamics and vehicle behavior, providing objective, high-precision detection that far exceeds human sensory capabilities for detecting unbalanced vehicle behavior.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital copy of the physical suspension system's behavior through sensor data. The control unit processes accelerometer and gyroscope signals to reconstruct suspension performance metrics, enabling precise measurement of leaf spring condition without direct physical measurement.

Inventive Principle:
Principle #26Copying

3Reliability

If continuous monitoring of leaf spring condition is implemented, then early failure detection is achieved, but energy consumption increases due to constant sensor operation

Engineering Contradiction:
Improveearly failure detection capabilityVSAvoidsensor system energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic monitoring instead of truly continuous monitoring. The control unit evaluates sensor data at specific intervals or under specific conditions (e.g., during suspension activity), providing early failure detection capability while allowing the system to enter low-power states during periods when monitoring is less critical.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent makes the monitoring system dynamic and adaptive. The control unit adjusts monitoring intensity based on vehicle operating conditions, suspension activity levels, and detected anomaly patterns, consuming more energy when failure risk is higher and less energy during normal operation.

Inventive Principle:
Principle #15Dynamics

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

Provides early detection of leaf spring failure, preventing loss of vehicle control and reducing the risk of accidents and repair costs by continuously monitoring and alerting the driver or automatically adjusting vehicle speed.

Implementation Method 1

an inertial measurement unit arranged at the wind-up centre of the first leaf spring, wherein the inertial measurement unit is adapted to provide a signal indicative of an actual path followed by the wind-up centre of the first leaf spring when the first leaf spring deflects

Methodology Applied
Scientific EffectInertial measurement: Inertia

Data Source

PatentEP4364983B1A vehicle suspension system
Publication Date: 2026.01.28 VOLVO TRUCK CORP
  • EP4364983B1 patent drawingFigure 1
  • EP4364983B1 patent drawingFigure 2
  • EP4364983B1 patent drawingFigure 3

AI summary

The invention relates to a vehicle (1) comprising a chassis (7), a pair of left and right wheels (3, 4) and a suspension system (10) for connecting the wheels (3, 4) and the chassis (7), wherein the suspension system (10) comprises: a wheel axle (2); a first leaf spring (6) connected to the wheel axle (2) in association with a corresponding wheel (4), wherein the first leaf spring (6) is connected also to the chassis (7) so as to, while deflecting, allow relative vertical movement between the chassis (7) and the wheel axle (2) and thereby also between the chassis (7) and the wheels (3, 4), wherein the first leaf spring (6) extends in a longitudinal direction of the vehicle (7) and is connected to the chassis (7) via a moveable connection (6b, 6c) configured to allow a wind-up centre (20) of the first leaf spring (6) to move in the longitudinal direction when the first leaf spring (6) deflects; an inertial measurement unit (8b) arranged at the wind-up centre (20) of the first leaf spring (6), wherein the inertial measurement unit (8b) is adapted to provide a signal indicative of an actual path (30) followed by the wind-up centre (20) of the first leaf spring (6) when the first leaf spring (6) deflects; wherein the vehicle (1) further comprises a control circuitry (13) configured to: compare the signal indicative of the actual path (30) followed by the wind-up centre (20) with a representation of a reference path (40) that the wind-up centre (20) of the first leaf spring (6) should follow when the first leaf spring (6) is well-functioning and deflects as intended; determine whether a difference between the actual path (30) and the reference path (40) is greater than a threshold value; and, if the determined difference is greater than the threshold, generate an alarm signal indicative of a detected or possibly detected leaf spring failure.