Multi-Motor Planetary Drive Torque Distribution

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Solution Overview

Problem

Existing drive arrangements for work machines, such as track-type tractors, are inefficient due to oversized motors required for high-torque operations, leading to high component costs and operational inefficiencies, especially during low-torque conditions, and lack efficient regeneration of power.

Innovation Solution

A drive arrangement utilizing three planetary gear sets and corresponding motors, allowing for simultaneous operation of all three to distribute power across multiple motors, reducing the maximum torque and power load on any single motor, and enabling regeneration during both low and high range operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If motors are oversized to accommodate high-torque operations, then the work machine can handle high-torque and high-power loading situations, but the motors operate inefficiently during low-torque conditions and incur high component costs

Engineering Contradiction:

Improvetorque handling capabilityVSAvoidmotor efficiency

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The drive system is segmented into multiple motors (at least two motors per traction device) that work together to share the torque load. This segmentation allows the system to handle high-torque operations collectively while enabling individual motors to operate at optimal efficiency levels during low-torque conditions, eliminating the need for single oversized motors.

Inventive Principle:

Principle #1Segmentation

2Force

If motors are oversized to accommodate high-torque operations, then the work machine can handle peak torque loads, but the component cost increases

Engineering Contradiction:

Improvetorque handling capabilityVSAvoidcomponent cost

Core Design Contradiction:

ForceVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Device complexity

If only two motors are used per traction device, then the device complexity is reduced, but the motors must be oversized and regeneration is limited

Engineering Contradiction:

Improvemotor configurationVSAvoidregeneration capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The system implements different operational characteristics for different motors under different conditions. During regeneration, the braked motor operates in generator mode while other motors continue propulsion, allowing localized functional differentiation that maximizes energy recovery without requiring complete system reconfiguration.

Inventive Principle:

Principle #3Local quality

4Force

If three motors are used during low range operations, then the torque load per motor is reduced, but the device complexity increases

Engineering Contradiction:

Improvetorque distributionVSAvoidmotor control system

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The system dynamically adjusts motor operation based on operating conditions. During low-range high-torque operations, all three motors are activated to share the load. During high-range operations or regeneration, the system dynamically reconfigures which motors are active, optimizing performance while managing complexity through adaptive control rather than fixed configuration.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7410437B2Planetary drive arrangement

Publication Date: 2008.08.12 CATERPILLAR INC

AI summary

A drive arrangement for a machine includes a first planetary gear set, a second planetary gear set, a third planetary gear set, a first motor, a second motor, and a third motor. The first, second, and third motors are drivingly connected to the first, second, and third planetary gear sets to simultaneously generate fewer than three separate output rotations.