Turbocharger Compressor Housing Segmentation for Scroll Shape Flexibility
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Solution Overview
Problem
Current turbocharger production methods, such as gravity die casting and die casting, face challenges in achieving an ideal shape for the discharge scroll chamber, leading to increased costs, complexity, and reduced efficiency due to limited flexibility in shape and increased number of parts.
Innovation Solution
A method where the scroll piece, shroud piece, and back plate are individually casted, with the back plate's outer peripheral concave surface forming part of the discharge scroll chamber, allowing for flexible shape formation and reduced part count, enabling smoother air flow and improved performance by varying the central mold's phase relative to the body mold for different vehicle types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If gravity die casting is used to form the compressor housing, then flexibility in shape is high and complicated shapes can be formed, but the casting cycle is long and productivity is poor
Solution Approach 1:
The compressor housing is divided into multiple separate components (scroll piece, shroud piece, outer peripheral annular piece) that are formed by die casting and then assembled together. This segmentation allows each part to be manufactured using high-productivity die casting processes while maintaining the capability to form complicated shapes through precise molding of individual segments.
Solution Approach 2:
Multiple separately cast components are assembled and combined to form the complete compressor housing assembly. The scroll piece, shroud piece, and outer peripheral annular piece are joined together to create the final structure, merging the advantages of die casting (productivity) with the ability to form complicated geometries.
2Shape
If sand mold is used for casting the compressor housing, then flexibility in shape is high, but surface roughness becomes large and efficiency of the compressor is deteriorated
Solution Approach 1:
The housing is segmented into multiple pieces that are each formed by die casting with sand cores. This allows the use of sand molding flexibility for complicated shapes while maintaining better surface finish compared to traditional sand casting of the entire housing, as die casting produces smoother surfaces than sand casting.
3Shape
If the compressor housing is formed by assembling three pieces (scroll piece, shroud piece, outer peripheral annular piece), then flexibility in shape of the discharge scroll chamber is secured, but the number of parts is increased and producing costs become high
Solution Approach 1:
The compressor housing is divided into three functional segments (scroll piece, shroud piece, outer peripheral annular piece) that can be independently formed by die casting. Each segment is optimized for its specific function and can be manufactured using standard die casting processes, balancing shape flexibility with manufacturing efficiency.
4Ease of manufacture
If a curved surface is formed on the back plate with constant cross-sectional shape, then manufacturing is simplified, but flexibility in shape of the discharge scroll chamber is limited
Solution Approach 1:
The back plate is designed with a curved surface whose cross-sectional shape varies at different locations along its length. This local variation in geometry allows the discharge scroll chamber to achieve optimal airflow characteristics in different regions, providing shape flexibility where needed while maintaining manufacturability through standard casting processes.
Data Source
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AI summary
The present invention provides a turbocharger capable of reducing its costs and enhancing its performance, and provides a method of producing the turbocharger. The turbocharger 1 includes a compressor housing 2, a bearing housing 6 and a back plate 3. A discharge scroll chamber 12 has such a shape that a cross-sectional area thereof gradually increases toward a discharge port in a circumferential direction. The compressor housing 2 includes a scroll piece 4 and a shroud piece 5 which are assembled to each other. The scroll piece 4 includes a suction port-forming portion 41, a suction-side concave surface 42 and a scroll outer periphery 43. The shroud piece 5 includes a shroud fit-in portion 51, an inner peripheral concave surface 52, a shroud surface 53 and a diffuser surface 54. The back plate 3 includes a facing surface 31, an outer peripheral annular fit-in portion 32 and an outer peripheral concave surface 33. The outer peripheral concave surface 33 has such a shape that a cross sectional shape thereof formed by a plane including a rotation axis of an impeller 13 gradually changes in the circumferential direction.