Method and apparatus for inductively heating valve seats

Abstract

A method and apparatus for simultaneously heating the conical surfaces of first and second valve seats lying generally in a given plane on an engine component, which method and apparatus comprises mounting two inductors for independent reciprocal and lateral movement with respect to a common frame and biased outwardly therefrom, moving the common frame toward the plane of the valve seats until each is stopped by contacting the engine component, locking the two inductors with respect to the common frame, moving the common frame away from the valve seats to provide the necessary coupling gap, and then energizing the inductors to inductively heat the valve seats preparatory to quench hardening thereof.

Having thus defined my invention, I claim: 
     
       1. A method of inductively heating the conical surface of a valve seat coaxially aligned with a bore in an engine component, said method comprising the following steps: a. providing a single turn inductor having a shape generally matching said surface;   b. mounting said inductor for reciprocal movement with respect to a frame and in a direction generally parallel to the axis of said bore;   c. biasing said inductor in a direction toward said engine component;   d. moving said frame toward said engine component with said inductor generally aligned with said valve seat;   e. stopping the movement of said inductor at a preselected location while said frame continues to move toward said engine component;   f. thereafter stopping the movement of said frame toward said engine component;   g. then, locking said inductor with respect to said frame;   h. moving said frame and inductor away from said engine component a selected distance to provide proper spacing of said inductor from said surface; and,   i. energizing said inductor to thereby inductively heat said surface.   
     
     
       2. A method as defined in claim 1 wherein said selected distance is between about 0.015 - 0.050 inches. 
     
     
       3. A method as defined in claim 1 wherein said selected distance is approximately 0.040 inches. 
     
     
       4. A method as defined in claim 1 including the step of: j. aligning said inductor in an axial direction with said valve seat as said frame is moving toward said engine component.   
     
     
       5. An induction heating device for heating the conical surface of a valve seat of an engine component preparatory to quench hardening, said engine component having a structural element fixed with respect to the center of said conical surface, said device comprising: a support frame fixed in a direction radial of said conical surface; an inductor having a shape generally matching said conical surface and two input leads for energizing said inductor; a carrier means for supporting said inductor; means for mounting said carrier means onto said support frame, said mounting means including means for limiting movement of said carrier means to only a direction radially of said conical surface; and, means on said carrier and adapted to coact with said structural element of said component for shifting to, and holding said carrier in, a position with said inductor generally concentric with said surface. 
     
     
       6. An induction heating device as defined in claim 5 including a first locator means on said frame and a second locator means on said carrier, said first and second locator means coacting to bias said carrier, and thus said inductor, into a preselected position with respect to said frame. 
     
     
       7. An induction heating device as defined in claim 6 wherein one of said locator means is a cam member and the other of said locator means is a follower member and means for biasing said members together in a direction generally axial of said conical surface. 
     
     
       8. An induction heating device as defined in claim 5 wherein said mounting means includes a flange on said carrier means, said flange lying in a plane generally perpendicular to the axis of said conical surface and said limiting means includes clamping means acting perpendicularly against said flange. 
     
     
       9. An induction heating device as defined in claim 8 wherein said clamping means includes a series of roller elements in contact with said flange and means for forcing said roller elements against said flange in a direction generally parallel to the axis of said conical surface. 
     
     
       10. An induction heating device as defined in claim 8 including a first locator means on said frame and a second locator means on said flange, said first and second locator means coacting to bias said flange, and thus said inductor, into a preselected position with respect to said frame. 
     
     
       11. An induction heating device as defined in claim 5 wherein said leads extend in a direction away from said conical surface, and including a transformer spaced from said frame, said transformer including a relatively fixed primary having a central opening with an axis generally parallel to the axis of said conical surface and a secondary within said opening, fixed onto said leads and movable with respect to said primary in a direction generally radial of said conical surface. 
     
     
       12. An induction heating device as defined in claim 11 including means for shifting said frame with respect to said fixed primary in a direction generally parallel to the axis of said conical surface and means for allowing said secondary to move within said opening in a direction generally parallel to said axis of said conical surface. 
     
     
       13. An induction heating device as defined in claim 12 including means for locking said frame with respect to said fixed primary during energization of said inductor. 
     
     
       14. An induction heating device as defined in claim 13 including means for selectively moving, in unison, said primary and said frame between a first position with said inductor spaced from said conical surface and a second position with said inductor adjacent said conical surface. 
     
     
       15. An induction heating device as defined in claim 5 including guide means for mounting said frame for reciprocal movement in a direction generally parallel to the axis of said conical surface. 
     
     
       16. An induction heating device as defined in claim 15 including means for selectively locking said frame with respect to said guide means. .Iadd. 17. An induction heating device for heating the conical surface of a valve seat of an engine component preparatory to quench hardening, said engine component having a structural element fixed with respect to the center of said conical surface, said device comprising: an inductor having a shape generally matching said conical surface and two input leads for energizing said inductor; a carrier means for supporting said inductor; means for mounting said carrier means with respect to said valve seat, said mounting means including means for limiting radial movement of said carrier means to a selected direction for maintaining a uniform spacing between said valve seat surface and said inductor when said carrier means shifts radially of said valve seat into a concentric relationship with said valve seat surface; and means on said carrier to coact with said structural element of said component for shifting to, and holding said carrier in, a position with said inductor generally concentric with said surface, said movement limiting means being a flange on said carrier means, said flange lying in a plane generally perpendicular to the axis of said conical surface when said inductor is concentric with said valve seat surface..Iaddend.