Articulated Loader Joint Bearings to Eliminate Body Rattling

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Solution Overview

Problem

Existing wheel loaders experience rattling between the front and rear machine bodies due to gaps in shaft support bushings, hydraulic hoses wear out from swinging with the lift arm, and rainwater accumulation in lamp brackets.

Innovation Solution

Implementing spherical plain bearings for shaft support and restricting hydraulic hose rotation, and designing lamp attachments to prevent rainwater ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If cylindrical bushings are used to support shafts for rotation, then rotation is enabled, but gaps between shafts and bushings cause rattling between machine bodies

Engineering Contradiction:
Improverotational movementVSAvoidrattling
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies spherical plain bearings instead of cylindrical bushings to support the shafts. The spherical geometry allows rotation while eliminating gaps that cause rattling, as the spherical surfaces maintain continuous contact during rotational movement about the vertical shaft and horizontal shaft.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If hydraulic hoses are allowed to swing with the lift arm, then movement flexibility is maintained, but the hoses contact other parts and wear out

Engineering Contradiction:
Improvemovement flexibilityVSAvoidhose durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses a protective sleeve or sheath to enclose the hydraulic hose, allowing it to swing with the lift arm while preventing contact with other parts. This flexible protective covering maintains the hose's movement flexibility while protecting it from wear and damage.

Inventive Principle:
Principle #30Flexible shells and thin films

3Device complexity

If simple brackets are used to attach head lamps, then structure is simplified, but rainwater accumulates inside the brackets

Engineering Contradiction:
Improvebracket structureVSAvoidrainwater accumulation
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent designs the lamp bracket with a sloped or angled surface that directs rainwater to drain away from the mounting area. By changing the geometric orientation of the bracket surface, water naturally flows off along the slope, preventing accumulation while maintaining structural simplicity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Reduces rattling between machine bodies, prevents hose wear, and ensures clear visibility and water drainage.

Implementation Method 1

The first supporting part includes a first spherical plain bearing. The first spherical plain bearing includes a first inner wheel including a convex curved sliding surface and provided on an outer circumferential surface of the center shaft, and a first outer wheel including a concave curved sliding surface and provided on the rear machine body.

Methodology Applied
Scientific EffectSpherical plain bearing: Ball Bearing

Implementation Method 2

a first inner wheel including a convex curved sliding surface and provided on an outer circumferential surface of the center shaft, and a first outer wheel including a concave curved sliding surface and provided on the rear machine body

Methodology Applied
Scientific EffectRolling contact: Ball Bearing

Data Source

PatentEP3951080B1Work machine
Publication Date: 2025.09.17 KUBOTA CORP
  • EP3951080B1 patent drawingFigure 1
  • EP3951080B1 patent drawingFigure 2
  • EP3951080B1 patent drawingFigure 3

AI summary

A working machine (1) includes a rear machine body (2B) on which an operator's seat (13) is mounted, a front machine body (2A) to which a working tool (9) is attached, a center shaft (252) having a first axis (XI) extending in a fore-and-aft direction, a first supporting part (260) supporting the center shaft rotatably relative to the rear machine body around the first axis, a coupling shaft (251) having a second axis (Z1) extending in a vertical direction and connected to the front machine body, and a second supporting part (270) supporting the center shaft rotatably relative to the coupling shaft relative to the second axis. The first supporting part includes a first spherical plain bearing (264), and the first spherical plain bearing includes a first inner wheel (264a) including a convex curved sliding surface and provided on an outer circumferential surface of the center shaft, and a first outer wheel (264b) including a concave curved sliding surface and provided on the rear machine body.