Planetary Gearbox Integral Service Brake Radial Layout

Solution Overview

Problem

High-speed off-highway machines face challenges with external disc-caliper service brakes due to size, cost, and corrosion issues, while internal multi-disc wet brakes suffer from torque transfer limitations and heat generation, necessitating a compact and efficient braking solution that protects from environmental corrosion.

Innovation Solution

A planetary gearbox with an integral service brake and parking brake, where the service brake is radially outward and operates between the output gear housing and a stationary spindle, utilizing large surface area discs and slits for oil guidance to manage heat and lubrication, and a spring-loaded piston for engagement, while the parking brake is integrated within the spindle to maintain assembly length and prevent crop disturbance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external output disc-caliper service brake is used, then braking capability is improved, but device size and cost increase

Engineering Contradiction:

Improvebraking capabilityVSAvoidbrake mass

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The service brake is merged with the planetary gearbox by integrating the brake rotor with the ring gear and the brake caliper with the gearbox housing. This combination eliminates the need for a separate external brake assembly, reducing overall device size and mass while maintaining braking capability through the enclosed brake mechanism that operates within the gearbox structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The brake mechanism is nested within the planetary gearbox structure. The brake rotor is positioned inside the ring gear, and the brake caliper is integrated into the gearbox housing, creating a compact nested arrangement where the braking system is contained within the existing gearbox boundaries rather than adding external mass.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If an external output disc-caliper service brake is used, then braking capability is improved, but environmental exposure increases corrosion risk

Engineering Contradiction:

Improvebraking capabilityVSAvoidenvironmental corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The brake mechanism is nested within the planetary gearbox structure. The brake rotor is positioned inside the ring gear, and the brake caliper is integrated into the gearbox housing, creating a compact nested arrangement where the braking system is contained within the existing gearbox boundaries rather than adding external mass.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The gearbox housing and ring gear act as protective enclosures for the brake components. This shielding effect protects the brake rotor and caliper from direct environmental exposure, reducing corrosion risk while maintaining braking functionality through the enclosed design.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If a wet multi-disc input brake is used, then service braking is achieved, but assembly length increases

Engineering Contradiction:

Improveservice brakingVSAvoidassembly length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The service brake is merged with the planetary gearbox by integrating the brake rotor with the ring gear and the brake caliper with the gearbox housing. This combination eliminates the need for a separate external brake assembly, reducing overall device size and mass while maintaining braking capability through the enclosed brake mechanism that operates within the gearbox structure.

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides a compact, environmentally protected braking system that effectively manages heat and lubrication, reducing assembly length and crop disturbance, while enhancing braking efficiency and durability by integrating the service and parking brakes within the gearbox.

Implementation Method 1

service brake is radially outward and operates between the output gear housing and a stationary spindle

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

utilizing large surface area discs and slits for oil guidance to manage heat and lubrication

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentEP2910395B1Planetary gearbox with integral service brake

Publication Date: 2019.02.13 FAIRFIELD MFG CO INC

Figure 1
Figure 1A
Figure 1B

AI summary

A planetary gearbox with substantial speed reduction includes a stationary spindle, an integral service brake, and a parking brake. The integral service brake resides radially outwardly with respect to the parking brake in a stacked arrangement such that axial space is conserved yielding an axially short and compact gearbox. An oil passageway extends radially through the spindle. A rotating input shaft drives the planetary gearbox and produces an output in the form of a rotatable housing. The service brake rotors have a large surface area and are keyed to the rotatable hub enabling efficient brake cooling and efficacious brake performance in a compact arrangement.