Bucket Pin Bearing Structure With Centralized Grease Equalization

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Solution Overview

Problem

The existing bearing structure for construction machines requires excessive grease due to increased volume of grease chambers and results in uneven grease supply to bushes, leading to potential over-supply on one side and under-supply on the other.

Innovation Solution

A modified bearing structure with a grease supply pipe disposed between side plates, allowing even distribution of grease to both bushes by filling both chambers simultaneously through a central grease passage, reducing the overall amount of grease needed and ensuring balanced lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the lid plate is disposed away from the inner surface of each boss part to accommodate mounting of nipple or bolt, then the grease chamber volume increases, but the amount of grease to be supplied increases

Engineering Contradiction:
Improvemounting accessibilityVSAvoidamount of grease
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

A grease supply pipe is introduced as an intermediary component to connect the external grease supply source to the grease chamber. This eliminates the need to position the nipple or bolt at the end of the boss pipe, allowing the lid plate to be disposed close to the inner surface of the boss part, thereby reducing grease chamber volume and the amount of grease required.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the nipple is provided in one grease chamber only, then the mounting is simplified, but the grease supply to right and left bushes becomes uneven

Engineering Contradiction:
Improvemounting simplicityVSAvoidgrease supply uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The grease supply system is segmented into two separate grease supply pipes, with each pipe connected to one of the two grease chambers (right and left). This segmentation allows independent control and uniform distribution of grease to both bushes, eliminating the uneven supply problem that occurs when a single nipple serves both chambers.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the nipple is mounted on one side for ease of operation, then the operation is simplified, but the grease supply to the other side becomes insufficient

Engineering Contradiction:
Improvegrease supply operationVSAvoidlubrication adequacy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The grease supply operation is divided into two independent channels through separate grease supply pipes. Each pipe delivers grease directly to its corresponding grease chamber, ensuring that both right and left bushes receive adequate lubrication simultaneously, thereby maintaining reliability while simplifying the operation.

Inventive Principle:
Principle #1Segmentation

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 modified structure reduces the total amount of grease required and ensures even distribution to both bushes, preventing over-supply or under-supply, thus enhancing lubrication efficiency.

Implementation Method 1

a grease supply operation from the nipple is performed while avoiding obstacles such as buckets, and hence, the nipple is mounted onto a side selected for ease of operation. Then, one grease chamber is filled with grease supplied from the nipple. Afterward, the other grease chamber is filled with the grease supplied through the grease passage

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP3892780B1Construction machine
Publication Date: 2024.02.07 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3892780B1 patent drawingFigure 1
  • EP3892780B1 patent drawingFigure 2
  • EP3892780B1 patent drawingFigure 3~4

AI summary

Provided is a construction machine in which a pair of boss parts (17L, 17R) coupled via a boss pipe (18) are welded to a tip end of an arm (7), a coupling pin (16) is rotatably supported in bushes (20L, 20R) of the respective boss parts (17L, 17R), and brackets (8b) of a bucket (8) are coupled to opposite ends of the coupling pin (16). An inner pipe (25) is fitted onto the coupling pin (16) on an inner circumferential side of the boss pipe (18), and defines a grease passage (26) between the coupling pin (16) and the inner pipe (25). Left and right gaps between the boss pipe (18) and the inner pipe (25) are closed with side plates (27L, 27R), and a pair of grease chambers (28L, 28R) communicating with each other via the grease passage (26) are defined. A grease supply pipe (29, 30) has a base end welded to a center of an outer circumferential surface of the inner pipe (25) in an axis (C) direction, and a tip end opened in a left side plate (7L) of the arm (7), so that a nipple (33) is mounted to the tip end.