Inverted Track Roller Seal Assembly for High-Speed Sealing Reliability

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Solution Overview

Problem

Existing track roller sealing strategies experience performance degradation or failure due to high rotational speeds and complex engineering complications, particularly in heavy-duty track-type machines operating in rugged conditions.

Innovation Solution

A track roller design featuring an inverted seal assembly with outer and inner seal carriers and face seals, utilizing radial compression and interference-fits to maintain a fluid seal between rotating components, enhancing durability and simplifying the construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal face seals are used to provide a rotating but fluidly sealed interface between track rollers and a supporting roller shaft, then sealing performance is improved, but the sealing system experiences high rotational speeds that result in performance degradation or failure

Engineering Contradiction:
Improvesealing performanceVSAvoidrotational speed of face seal components
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The face seal assembly is divided into separate functional components: an inner seal carrier fixed to the roller shaft, an outer seal carrier fixed to the roller rim, and face seals positioned between them. This segmentation allows each component to perform its specific function independently, with the inner seal carrier handling rotation at lower speeds and the outer seal carrier providing fluid sealing, thereby reducing the rotational speed burden on the sealing system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The face seal acts as an intermediary element between the inner seal carrier and the outer seal carrier. This intermediary structure provides a fluidly sealed interface that accommodates the relative motion between the roller shaft and roller rim without requiring the entire sealing system to withstand high rotational speeds, thus improving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If existing sealing strategies are used to accommodate high rotational speeds, then sealing function is maintained, but the engineering and design of other parts of the track roller becomes complicated

Engineering Contradiction:
Improvesealing functionVSAvoidengineering complexity of track roller
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing system is segmented into distinct carriers and seal elements, each with defined functions. The inner seal carrier is fixed to the roller shaft while the outer seal carrier is fixed to the roller rim, creating a modular assembly that simplifies the overall engineering design by assigning specific roles to each component rather than requiring a complex integrated solution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of designing a complex sealing system to accommodate high rotational speeds directly, the invention inverts the approach by using the roller shaft and roller rim as the primary rotating structures and positioning the sealing components to work with their relative motion. This inversion simplifies the design by leveraging the existing rotational mechanics rather than adding complex sealing mechanisms.

Inventive Principle:
Principle #13The other way round (Inversion)

3Strength

If track rollers are constructed to withstand severe loading conditions, then durability is improved, but the weight and complexity of the track-type machine increases

Engineering Contradiction:
Improvedurability of track rollerVSAvoidweight of track-type machine
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The face seal assembly uses parameter changes in the sealing mechanism design, specifically using an inverted configuration where the outer seal element is radially inward of the outer seal ring and squeezed in radial compression. This parameter change allows the seal to maintain effectiveness under severe loading conditions without requiring additional weight, as the radial compression provides the necessary sealing force.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The seal assembly combines different materials with complementary properties: the outer seal ring and inner seal ring provide structural support, while the outer seal element and inner seal element provide fluid sealing. This composite approach allows the seal to withstand severe loading conditions through material composition rather than increasing the overall weight of the track roller.

Inventive Principle:
Principle #40Composite materials

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 design provides a robust and efficient sealing mechanism that withstands severe loading conditions, reducing performance degradation and failure, while optimizing lubrication and simplifying engineering complexity.

Implementation Method 1

Each outer seal element is radially inward of the respective outer seal ring and squeezed in radial compression to form a fluid seal with the respective outer seal carrier

Methodology Applied
Scientific EffectRadial compression: Compression

Implementation Method 2

metal face seals are used to provide a rotating but fluidly sealed interface between track rollers and a supporting roller shaft

Methodology Applied
Scientific EffectFluid sealing: Lubrication

Data Source

PatentEP4313742B1Track roller for undercarriage system having inverted seal, and roller rim for same
Publication Date: 2026.02.18 CATERPILLAR INC
  • EP4313742B1 patent drawingFigure 1
  • EP4313742B1 patent drawingFigure 2~3
  • EP4313742B1 patent drawingFigure 4~6

AI summary

A track roller (30) for an undercarriage system (14) includes a roller rim (32) defining a roller axis and including a first seal bore (40) formed in a first axial end (38) and a second seal bore (44) formed in a second axial end (42). A roller shaft (46) extends through the first seal bore (40) and the second seal bore (44), and may include a straight shaft having an uninterrupted cylindrical outer surface. A first seal assembly (58) includes a first outer seal carrier (60) interference-fitted within the first seal bore (40), and a second seal assembly (66) includes a second outer seal carrier (68) interference-fitted within the second seal bore (44). The first seal assembly (58) and the second seal assembly (66) include a first face seal (64) and a second face seal (72), respectively, each including an outer seal ring (74,76) and an outer seal element (78,80), and an inner seal ring (82,84) and an inner seal element (86,88), where each outer seal element (78,80) is radially inward of the respective outer seal ring (74,76) and squeezed in radial compression to form a fluid seal with the respective outer seal carrier (60,68).