Arm Boss Bearing Grease Passage for Even Bucket Pin Lubrication
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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 experiences 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 pair of boss parts coupled via a boss pipe, featuring a coupling pin with an inner pipe and side plates forming annular grease chambers, and a grease supply pipe that fills both chambers simultaneously, reducing grease volume and ensuring even distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lid plate is disposed away from an inner surface of each boss part to mount a nipple or bolt, then the grease chamber volume increases, but the amount of grease to be supplied increases excessively
Solution Approach 1:
The nipple is nested within the boss part structure, specifically positioned within the inner circumferential space of the boss part. This allows the mounting of the nipple without requiring the lid plate to be disposed away from the inner surface, thereby maintaining a compact grease chamber volume while still enabling easy grease supply operation.
2Device complexity
If the nipple is provided in one grease chamber, then the structure is simplified, but the grease supply to right and left bushes becomes uneven
Solution Approach 1:
The grease supply system is segmented into two independent grease supply paths, with one nipple provided for each grease chamber (left and right). This segmentation allows independent control and supply of grease to each bush, ensuring uniform grease distribution while maintaining structural simplicity through the use of identical standardized components.
3Productivity
If grease is supplied sequentially to one grease chamber first, then to the other, then the supply process becomes simple, but the grease supply to right and left bushes becomes noticeably uneven
Solution Approach 1:
The grease supply system is designed with two nipples that enable simultaneous grease supply to both grease chambers from the beginning. This preliminary arrangement of dual supply paths eliminates the need for sequential supply operations, allowing both bushes to receive grease uniformly and simultaneously, thereby achieving both operational simplicity and supply uniformity.
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
This configuration decreases the total grease amount supplied and ensures even lubrication to both bushes, preventing excessive or insufficient grease distribution.
Implementation Method 1
the grease is supplied through a grease passage (26) to both the right and left grease chambers (28R, 28L) simultaneously
Data Source
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.