Cold-Chamber Piston Bayonet Lock and Spring Bush Design
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Solution Overview
Problem
Current pistons for die casting machines experience frequent wear and require frequent replacement due to surface material wear, and existing vacuum technology in die casting does not efficiently maintain porosity-free and thin-walled piece production, necessitating improvements in locking systems and cooling efficiency.
Innovation Solution
A piston design featuring a separate bayonet lock ring with semicircular parts and a conical spring bush that adjusts to the container diameter, allowing for easy assembly and replacement of wear-prone components, and incorporating a spring bush with a conical spring ring for enhanced vacuum and cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the external body is made as a single integrated piece, then the structure is simpler, but the wear-prone surfaces require complete replacement leading to higher costs and longer downtime
Solution Approach 1:
The external body is divided into multiple independent components: the main external body structure, a replaceable bush for the locking ring groove, and a sealing ring. This segmentation allows the wear-prone bush to be replaced separately from the main body, reducing replacement costs and downtime while maintaining structural integrity.
2Device complexity
If the bayonet lock is integrated into the external body, then the assembly has fewer parts, but the locking surfaces wear down requiring frequent complete replacement
Solution Approach 1:
The bayonet lock ring is extracted as a separate component from the external body, with its groove positioned in the external body but the locking ring itself being replaceable. This allows the locking mechanism to be maintained independently from the main body structure, extending the operational life of the assembly.
Solution Approach 2:
The bush in the locking ring groove is made from a different material optimized for wear resistance compared to the main external body. This local quality enhancement targets the specific area subject to wear (the locking interface) while keeping the rest of the structure simple and cost-effective.
3Device complexity
If the piston uses conventional cooling, then the structure is simpler, but the vacuum capacity is insufficient for producing thin-walled porosity-free pieces
Solution Approach 1:
The cooling channels are nested within the external body structure itself, with the bayonet lock ring groove and cooling passages integrated into the same component. This nested arrangement provides efficient cooling for thin-walled pieces without adding external cooling apparatus, maintaining structural compactness while achieving high vacuum capacity.
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 design extends the life of the piston, reduces material costs by allowing selective replacement of wear-prone parts, and achieves high-grade vacuum conditions, resulting in improved cast piece quality and reduced machine downtime.
Implementation Method 1
a conical spring ring that, mounted under the same, i.e. between the external body of the piston and the aforementioned spring bush, aims to adapt the diameter of the spring bush so that it adjusts to the expansion of the container and to counteract the wear of the bush, thanks to the expansive pressure that said ring itself exerts
Implementation Method 2
given that the described conical spring ring is always in contact with the external body of the piston that is cooled via the aforementioned cooling fluid, the spring bush is also advantageously cooled to counteract the high temperatures that the liquid metal injected reaches
Data Source
Figure 1
Figure 2~3
AI summary
A PISTON FOR COLD-CHAMBER INJECTION MACHINES comprising a support (2) and an external body (3) with a sealing ring (5), joined by a bayonet lock ring (6) independent of the external body (3) and divided into two parts (6a) fitted onto a groove (21) in the support (2) and connected by long screws (7) inserted into threaded holes (61). The piston preferably includes a spring bush (4) as a part that adjusts to the container, independent of the external body (3) and of the bayonet lock ring (6), under which a conical spring ring (8) is included which exerts pressure on the two parts that form the bush (4), tending to expand the same. The piston also includes alternating transverse grooves (81) along the edges thereof for receiving conical metal tips (9) inserted through holes (63) in the bayonet lock ring (6).