Rotor housing for a rotary piston type engine and method for manufacturing the same

Abstract

Rotor housing for a rotary piston type engine comprising a liner made of a metal sheet having one surface formed with teeth-like projections, said liner being formed into a trochoidal configuration with said one surface directed outside, and an aluminum based metal housing substrate cast around the liner whereby firm bonding is assured between the liner and the housing substrate due to the existence of the projections. Novel method for manufacturing such a rotor housing is also disclosed.

We claim: 
     
       1. Method for manufacturing a rotor housing for a rotary piston type engine having a rotor housing liner with a cold zone located substantially opposite an ignition plug opening, comprising steps of providing a rolled metal sheet, scratching one side of said metal sheet to provide a rough surface, welding opposite terminal edges of said metal sheet together with said rough surface directed outside, forming said metal sheet into a trochoidal configuration to provide a liner with the welded edges disposed within a cold zone of the completed housing, and casting under pressure an aluminum based material around said liner with terminal edges welded to form a housing substrate. 
     
     
       2. Method in accordance with claim 1 in which the liner is formed into a trochoidal configuration having a major axis longer than that of a nominal trochoidal configuration which is larger than a desired configuration of the rotor housing by an average shrinkage during manufacture of the housing, and a minor axis shorter than that of the nominal trochoidal configuration. 
     
     
       3. Method in accordance with claim 1 in which a plurality of saw-teeth like projections are formed to provide the rough surface by the scratching step. 
     
     
       4. Method in accordance with claim 1 in which a plurality of saw-teeth like projections are formed in staggered relationship with each other on said one side of the metal sheet to provide said rough surface by the scratching step. 
     
     
       5. Method in accordance with claim 1 in which said metal sheet is formed into a circular configuration with said edges flattened to the welding step. 
     
     
       6. Method in accordance with claim 1 in which said metal sheet is formed into a trochoidal configuration before the edges are welded together. .Iadd. 7. A method of manufacturing a rotor housing for a rotary piston type engine having a rotor housing liner with a cold zone located substantially opposite an ignition plug opening, comprising the steps of providing a metal sheet, treating one side of said metal sheet to provide a rough surface, bonding opposite terminal edges of said metal sheet together with said rough surface directed outside, forming said metal sheet into a trochoidal configuration to provide a liner with the bonded edges disposed within a cold zone of said housing and casting an aluminum based material around said liner to form a housing substrate. .Iaddend. .Iadd. 8. A method in accordance with claim 7 wherein said treating step comprises scratching said one side of said metal sheet. .Iaddend..Iadd. 9. A method in accordance with claim 8 wherein said scratching step includes forming a plurality of sawteeth like projections on said one side of said metal sheet. .Iaddend..Iadd. 10. A method in accordance with claim 7 wherein said bonding step comprises welding together said metal sheet terminal edges. .Iaddend. .Iadd. 11. A rotor housing for a rotary piston type engine, comprising a liner provided by a rolled metal sheet which is scratched at one side to form a rough surface and has opposite terminal edges welded together to form a trochoidal configuration with said rough surface directed outside, and an aluminum based metal housing substrate cast around the liner, said welded terminal edges of the metal sheet being disposed within a cold zone of the housing located substantially opposite an ignition plug opening. .Iaddend. .Iadd. 12. A rotor housing in accordance with claim 11 in which said liner is made of iron. .Iaddend..Iadd. 13. A rotor housing in accordance with claim 11 in which said rough surface of the liner is constituted by a plurality of saw-teeth like projections formed by scratching the surface. .Iaddend. .Iadd. 14. A rotor housing in accordance with claim 13 in which said projections are arranged in staggered relationship with each other. .Iaddend. .Iadd. 15. A rotor housing for a rotary piston type engine, comprising a liner provided by a metal sheet which is treated at one side to form a rough surface and has opposite terminal edges bonded together to form a trochoidal configuration with said rough surface directed outside, and an aluminum based metal housing substrate cast around the liner, said bonded terminal edges of the metal sheet being disposed within a cold zone of the housing located substantially opposite an ignition plug opening. .Iaddend. .Iadd. 16. A rotor housing in accordance with claim 15 in which said liner is made of iron. .Iaddend..Iadd. 17. A rotor housing in accordance with claim 15 in which said rough surface of the liner is constituted by a plurality of saw-teeth like projections formed by treating the surface. .Iaddend..Iadd. 18. A rotor housing in accordance with claim 17 in which said projections are arranged in staggered relationship with each other. .Iaddend.