Rotary Torque Input Fixture for Solid Axle Road Simulation

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Solution Overview

Problem

Current road simulation test methods for vehicles with solid axles require modifications, such as removing the differential cover and ring gear, and introduce unwanted inertial loads due to the use of linear actuators, which affect the accuracy of test results by not replicating real-time driving conditions.

Innovation Solution

A rotary torque input fixture system using a rotary actuator, torsional load cell, and telescopically connected drive shaft to apply rotary torque to the axle assembly without modifications, monitored by an angular displacement transducer and controller, ensuring accurate replication of torsional loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adapters are used to attach the axle to the fixture, then the axle can be tested in the road simulation test, but the differential cover and ring gear must be removed which affects the mechanical properties of the axle

Engineering Contradiction:

Improvevalidity of road test simulationVSAvoidmodification requirement

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary coupling mechanism that connects the rotary actuator to the axle without requiring direct attachment to the differential cover and ring gear. This intermediary system allows torque application while preserving the integrity of the axle components, thus maintaining mechanical properties while enabling testing.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the torque application function from the traditional adapter-based system and implements it through a rotary actuator that applies torque directly to the axle shaft. This eliminates the need to remove the differential cover and ring gear, as the torque is applied through a different pathway that does not interfere with these components.

Inventive Principle:

Principle #2Taking out (Extraction)

2Force

If a linear actuator is used to input torque to the axle, then torque can be applied, but un-sprung mass is added which creates unwanted inertial loads

Engineering Contradiction:

Improvetorque applicationVSAvoidun-sprung mass

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The patent replaces the linear actuator mechanism with a rotary actuator system. This substitution eliminates the need for the linear-to-torsional conversion mechanism (pair of arms) and its associated un-sprung mass. The rotary actuator directly applies torque to the axle, reducing unwanted inertial loads while maintaining effective torque application.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If a linear actuator with pair of arms is used to convert linear motion to torsional motion, then torque can be applied to the axle, but the load path does not match real-time driving conditions

Engineering Contradiction:

Improvetorque inputVSAvoidaccuracy of test results

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

Instead of converting linear motion to torsional motion through a pair of arms (as in the linear actuator system), the patent inverts the approach by using a rotary actuator that directly generates torsional motion. This inverted mechanism creates a load path that more closely resembles real-time driving conditions, where torque is naturally applied in a rotational manner to the axle, thereby improving measurement precision and accuracy of test results.

Inventive Principle:

Principle #13The other way round (Inversion)

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 system allows for accurate simulation of axle windup without modifying the axle and reduces errors by applying torsional loads that match real-time driving conditions, ensuring valid test results.

Implementation Method 1

a torsional load cell, and a drive shaft connection portion... as the rotary actuator rotates the input shaft, a signal indicative of a torsional load is communicated by the torsional load cell

Methodology Applied

Scientific EffectTorsional deformation: Deformation

Implementation Method 2

an angular displacement transducer attached to the rotary actuator and in communication with the controller, wherein the angular displacement transducer is configured to transmit a signal indicative of an angular displacement applied to the input shaft

Methodology Applied

Scientific EffectAngular displacement: Displacement

Data Source

PatentUS11761852B2Rotary torque input fixture for testing a solid axle in a road simulation test

Publication Date: 2023.09.19 FCA US LLC

AI summary

A road simulation test system and method for testing torsional strain input to an axle assembly having an input shaft and a suspension system, including a torque input module configured to apply rotary torque to the axle assembly. The torque input module includes a rotary actuator, a torsional load cell, a drive shaft connection portion, and a controller in communication with the rotary actuator and the torsional load cell, wherein upon receipt of an instruction from the controller, the rotary actuator is configured to rotate the input shaft to apply the rotary torque to the axle assembly, and as the rotary actuator rotates the input shaft, a signal indicative of a torsional load is communicated by the torsional load cell to the controller to monitor the rotary torque applied to the axle assembly.