Cam Roller Pin Lubricant Paths for Variable-Speed Cam Followers

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Solution Overview

Problem

Internal combustion engines face challenges in effectively lubricating cam follower assemblies, particularly in distributing lubricant to reduce friction and maintain surface cooling, especially under varying cam roller speeds.

Innovation Solution

A cam roller pin with a reservoir and multiple lubricant paths, including first, second, and third lubricant paths, is designed to receive and distribute lubricant efficiently, with outlets positioned outside the load zone to prevent lubricant pressure buildup and ensure consistent lubrication across the cam roller and pin surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single lubricant path is used, then the device complexity is reduced, but the lubrication distribution becomes insufficient under varying cam roller speeds

Engineering Contradiction:

Improvelubrication distributionVSAvoidlubricant path configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The lubricant delivery system is segmented into multiple independent lubricant paths (first, second, and third paths) that can independently supply lubricant to different regions of the cam roller. This segmentation allows each path to be optimized for specific speed ranges or load zones, improving overall lubrication adaptability without requiring a single complex adjustable mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different lubricant paths are configured with different characteristics (such as path dimensions, outlet positions, or flow rates) to provide locally optimized lubrication. For example, certain paths may be designed to deliver more lubricant during high-speed conditions while others optimize for low-speed operation, ensuring that each region of the cam roller receives appropriate lubrication quality for its specific operating conditions.

Inventive Principle:

Principle #3Local quality

2Reliability

If lubricant outlets are positioned in the load zone, then direct lubrication of the contact surface is improved, but lubricant pressure buildup causes backflow and reduces lubrication consistency

Engineering Contradiction:

Improvelubrication consistencyVSAvoidlubricant pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The lubricant outlets are extracted from the high-pressure load zone and repositioned to locations outside this zone. This allows the lubricant to be delivered to the cam roller surface without being subjected to the extreme pressures present in the direct contact load zone, preventing backflow into the lubricant paths while still achieving effective surface lubrication through the outlet positioning.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The lubricant paths act as intermediary channels that transport lubricant from the reservoir to strategic outlet positions. These intermediaries allow lubricant to bypass the high-pressure load zone during delivery, using the paths as protected conduits that maintain positive flow direction and prevent pressure-induced backflow while still enabling lubricant to reach the cam roller surface for effective lubrication.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 improved lubrication to the cam roller and pin surfaces, maintaining effective lubrication during both low and high-speed conditions, and prevents lubricant backflow by positioning outlets outside the load zone, ensuring consistent performance and reducing friction.

Implementation Method 1

The pin includes a reservoir disposed at a radially outer and upper end of the pin configured to receive lubricant for lubrication of the cam roller rotating on the pin

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 2

a first lubricant path extending radially inward from the reservoir, a second lubricant path extending from the first lubricant path to a second lubricant path outlet at the radially outer and lower end of the pin

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11802615B1Cam follower assembly and cam roller pin with lubricant path

Publication Date: 2023.10.31 DEERE & CO

AI summary

A cam roller pin is rotationally fixed and defines a pin axis around which a cam roller is configured to rotate and apply a load at a load zone at a radially outer and lower end of the pin. The pin includes a reservoir configured to receive lubricant for lubrication of the cam roller rotating on the pin, a first lubricant path extending radially inward from the reservoir, a second lubricant path extending from the first lubricant path to a second lubricant path outlet, and a third lubricant path extending from the first lubricant path to a third lubricant path outlet.