US3696224A

US3696224A - Transformer & inductor unit for heating valve seats

Info

Publication number: US3696224A
Application number: US151496A
Authority: US
Inventors: John C Lewis
Original assignee: Park Ohio Industries Inc
Current assignee: Park Ohio Holdings Inc
Priority date: 1971-06-09
Filing date: 1971-06-09
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: AU432404B2; CA922790A; AU3571871A; DE7143333U; GB1364172A; SE379784B; BR7200656D0; FR2140987A5; IT945043B

Abstract

An induction heating device for inductively heating the conical surface of a valve seat in an engine block for subsequent quench hardening including a fixed multi-turn transformer primary winding having a central opening and a carrier having both the secondary of the transformer and the inductor mounted thereon wherein the carrier is selectively shiftable between a first position with the inductor spaced away from the valve seat and a second position with the inductor magnetically coupled to the valve seat and with the secondary then within the primary.

Description

United States Patent 1151 3,696,224 Lewis [45] Oct. 3, 1972 [54] TRANSFORMER & INDUCTOR UNIT 2,496,950 2/ 1950 Marcus et a1. ..2l9/ 10.73 FOR HEATING VALVE SEATS 2,757,268 7/1956 Edwards ..2l9/ 10.79 X 9 2 764 660 9/1956 Grenoble ..219/10.79 X 72 I t 1 wemwmh 3,472,991 10/1969 Seulen et a1. ..219/10.79 [73] Assignee: Park-Ohio Industries Inc., Cleve- FOREIGN PATENTS 0R APPLICATIONS and, 1,537,394 7/1968 France ..219/10.79 22 Filed: June 9,1971 1 H h Primary ExaminerWil iam e a [21] Appl 15l496 Attorney-Meyer, Tilberry & Body [52] US. Cl. ..2l9/l0.57, 219/10.79, 266/5 E, ABSTRACT 336/119 336/129 An induction heatin g device for 1nduct1ve1y heating 3; g g gg g the conical surface of a valve seat in an engine block 1 le 0 I are i for subsequent quench hardening including a fixed multi-tum transformer primary winding having a central opening and a carrier having both the secondary [56] References Cited of the transformer and the inductor mounted thereon UNITED STATES PATENTS whereinthe carrier is selectively shiftable between a first position w1th the inductor spaced away from the 2,223,902 12/1940 Somes ..336/119 X valve Seat and a second position with the inductor 2,241,431 5/1941 Somes ..266/51 E magnetically coupled to h valve Seat and with the 2,256,873 9/ 1941 Somes ..266/5 E secondary then within the primary 2,280,861 4/1942 Somes ..336/119 2,281,297 4/1942 Somes ..336/1 19 X 3 Claims, 5 Drawing Figures PATENTEDncrs SHEET 1 BF 2 FIG INVENTOR. JOHN C. LEWIS Me 74mm, 5 Bad,

ATTORNEYS P'A'TENTED 0:13 m2 SHEET 2 BF 2 INVENTOR. JOHN C. LEWIS ATTORNEYS TRANSFORMER & INDUCTOR UNIT FOR HEATING VALVE SEATS The present invention relates to the art of induction heating and more particularly to a transformer and inductor unit for heating the valve seat of an engine block preparatory to quench hardening.

The invention is particularly applicable for inductively heating the conical surface of a valve seat in a gray cast iron engine block for an internal combustion engine, and it will be described with particular reference thereto; however, it must be appreciated that the invention has much broader applications and may be used for inductively heating many cylindrical, conical and flat surfaces.

In recent time, considerable work has been devoted to induction heating devices for heating the conical surface of a valve seat in an engine block preparatory to quench hardening thereof. Generally, an inductor is positioned adjacent the cylindrical surface and energized by a high frequency power source. This causes induction heating of the valve seat for subsequent quench hardening. The inductor must be movable into and out of the valve seat for processing successive engine blocks. This presents a substantial difficulty in an induction heating installation. The inductor itself must be connected onto the secondary of a transformer used to couple the power source to the inductor. Because of the reciprocal movement of the inductor, it has been suggested to use flexible leads between the inductor and the secondary. Such flexible leads cause power loss, and the possibility of damage to the leads is also present. Also, such an arrangement requires flexible leads for directing coolant to the inductor. To overcome the disadvantages of providing flexible connections to the inductor itself, it has been suggested to connect the inductor rigidly to the secondary of the transformer and have the secondary and primary reciprocate as a unit. This then requires flexible connections between power source and the primary winding of the transformer. Again, flexible cooling leads are also required in this type of installation.

These and other disadvantages are completely overcome by the present invention wherein the primary winding of the transformer is fixedly mounted and the inductor is secured with respect to the secondary of the transformer on a carrier that is reciprocally mounted within the primary. In this manner, flexible connections are limited only to the coolant lines for both the transformer secondary and the inductor itself. These lines can be made flexible with less difficulty than conductor leads.

In accordance with the present invention, there is provided an induction heating device for inductively heating the conical surface of a valve seat in an engine block for subsequent quench hardening which device comprises a fixed multi-turn primary winding having a central opening with an axis generally perpendicular to the turns, a carrier having first and second longitudinally spaced portions with a single turn sheet type secondary adjacent the first portion and a single turn inductor adjacent the second portion and leads electrically connecting the secondary and the inductor, and means for selectively shifting the carrier generally along the axis of the primary between a first position with the inductor substantially spaced from the valve seat a distance not corresponding to the proper magnetic coupling distance and a second position with the inductor magnetically coupled to the valve seat at the proper distance and with the secondary within the primary winding whereby energizing of the primary causes inductive heating of the valve seat. In this manner, the inductor may be moved away from the engine block for insertion and removal of the engine block from the induction heating station. Also, it is possible to move the inductor to change the spacing with the valve seat without moving the primary. Movement of the inductor carries with it the movement of the secondary so that the secondary is then positioned adjacent the primary winding of the transformer for proper energization of the inductor when the inductor is moved into the proper position to create the proper gap between the inductor and the valve seat.

The primary object of the present invention is the provision of a transformer and inductor unit for induction heating of the valve seat of an engine block preparatory to quench hardening, which unit simplifies the electrical and coolant connections for the total installation.

Another object of the present invention is the provision of a transformer and inductor unit for induction heating of the valve seat of an engine block preparatory to quench hardening, which unit is easy to install and reduces the number of flexible connections in the installation.

These and other objects and advantages will become apparent from the following description taken together with the accompanying drawings in which:

FIG. 1 is a schematic side elevational view illustrating the present invention;

,FIG. 2 is a partial cross-sectional view taken generally along line 22 of FIG. 1;

FIG. 3 is a cross-sectional view taken generally along line 3-3 of FIG. 1;

FIG. 4 is a cross-sectional view taken line 4-4 of FIG. 1; and,

FIG. 5 is a partial side elevational view illustrating, somewhat schematically, a second embodiment of the present invention.

Referring now to the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting same, FIG. 1 shows an engine block A having a plurality of spaced exhaust ports B with valve seats 10, lower rod bores 12 and machined surfaces 14. A plurality of induction heating devices C are positioned with one device above each of the exhaust ports. These induction heating devices operate somewhat in unison with independent vertical adjustment; however, they are substantially identical in structure and only one of these units or devices will be described in detail.

A plurality of relatively fixed

multi-turn primaries

20, 22, 24 are positioned directly above the exhaust ports B and are connected in series by

leads

30, 32 with an appropriate high frequency power source 34. The primaries are formed from a hollow conductor, and coolant is circulated therethrough by inlet 40 and outlet 42. The fixed primary 20 used with the first of the induction heating devices C will be used in the following description.

A carrier 50 includes an upper support plate 52 and a lower insulated body 54 and is mounted to be generally along reciprocated within an appropriate guide arrangement schematically disclosed as

guide surfaces

56, 58. A single sheet secondary 60 having a hollow'structure is secured onto one end of the carrier 50 and includes a ductor 80 secured onto the insulated body 54 of carrier 50. Coolant is circulated through secondary, through

leads

70, 72 and through inductor 80. A variety of arrangements could be used for the coolant circulating arrangement; however, in accordance with the illustrated embodiment of the present invention, there is provided a coolant inlet 90 connected by a flexible hose to a source of' coolant, not shown. A circumferentially extending baffle 92 and anaxially extending baffle 94 causes the coolant to flow through the secondary 60 in accordance with the arrows shown in FIGS. 1, 2 and 3. Coolant then flows down through lead 70, around inductor 80 and up lead 72 into the secondary 60. Thereafter, the coolant passes then again through a different portion of the secondary, as shown by the arrows,.to the outlet 96 which is connected by a flexible lead to the next induction heating unit or to an ap propriate sump.

Carrier 50 includes a lower hose 100 for supporting a locator tip 102 which coacts with the bore 12 to locate the inductor 80 concentrically with respect to the valve seat 10 when the carrier 50 is in its lower position. To reciprocate the carrier, there is provided appropriate means, illustrated as a double acting pneumatic cylinder 1 10 connected onto support plate 52 by a rod 112. Of course, other arrangements could be used for moving the carrier 50 in a vertical direction with respect to the engine block A. For instance, it is possible to employ a threaded rod driven by a rotating nut. The movement can be between a position spaced from the engine block to the proper heating position or from a position with the inductor generally contacting the block to a back-off position with the inductor in the proper heating position.

In accordance with one operation, a cylinder 110 is actuated to move the carrier 50 into an upper position. In this manner, an engine block A can be moved into proper position with the respective exhaust ports aligned with each of the induction heating devices C. Thereafter, the cylinder 110 moves the carrier 50 downwardly into the position shown in FIG. 1 with the inductor 80 magnetically coupled with the valve seat 10. The tip 102 locates the inductor 80 concentric with the valve seat. Downward position of the carrier can be controlled by a sensing device, a servomechanism or a fixed position. Also, the tip 102 could contact the surface 14 for location. When the carrier is in the'ir'iward, active position, the power source 34 energizes the inductor to inductively heat the valve seat for. subsequent quenching in a manner well known in the art. After this has been done, the carrier 50 isthen shifted into its upper position for removal of the engine block and insertion of a subsequent engine block.

In accordance with another operation, the inductor carrier 50 can be shifted from any position which does not provide a proper coupling gap between the inductor and valve seat to a position where the proper gap is obtained. 1

Referring now .to FIG.- 5,, a modification of the present invention is illustratedln accordance with this modification, theprimary surrounds the secondary 122, similar to the secondary 60, and the body 124 mounts inductor 126.; In this embodiment, the inductor 126 is only closely spaced from the secondary 122.

Leads

130, 132 are relatively short as compared to the

leads

70, 72 in the previously discussed embodiment of the present invention. Thus, the length of the carrier is substantially reduced. Coolant is introduced into the secondary through inlet 134 and is withdrawn from the secondary through outlet 136. The coolant arrangement through the secondary, the connecting leads and the inductor is substantially similar to the coolant system employed in the first embodiment of theinvention.

By using the fixed primary, it is possible to employ different carriers when different types of valveseats are to be heated. Also, in some instances it may be possible to employ a plurality of carriers on an indexing mechanism each of the carriers having a difierent type of inductor and a similar secondary structure. With this type of system, when a given induction heating operation is to be performed, the proper carrier is indexed into position with the primary and then moved downwardly through the primary into proper heating position.

Having thus defined my invention, I claim:

1. An induction heating device for inductively heating the conical surfaces of two adjacent valve seats in an engine component for subsequent quench hardening, said device comprising: a heating unit for each valve seat, each of said units having a fixed multi-turn primary winding having a central opening with an axis generally perpendicular to said turns and a given axial length; a carrier having first and second longitudinally spaced portions, a single turn sheet type secondary adjacent said first portion and having a central axis generally coinciding with said axis of said primary winding, a single turn inductor adjacent said second portion and having a central axis generally parallel with said axis of said primary, and leads electrically connecting said secondary and said inductor; means for selectively shifting said carrier generally along said axis of said primary winding between a first positionand a second position with said inductor magnetically coupled to the valve seat associated with said unit at a desired spacing and with said secondary within said primary winding whereby energizing of said .primary causes inductive heating of said valve seat; and, said carrier including a third portion spaced from said second portion on the side opposite to said first portion and a locator means fixed onto said third portion and movable with said inductor, said locator means having an outwardly protruding nose coacting with a bore in said component and concentric with said conical surface for centering said inductor with said valve seat surface associated with said unit when said carrier is in said second portion.

2. An induction heating device as defined in claim 1 wherein said secondary includes a single turn winding having a generally cylindrical portion.

3. An induction heating device as defined in claim 1 wherein said inductor'is only slightly spaced from said secondary.

Claims

1. An induction heating device for inductively heating the conical surfaces of two adjacent valve seats in an engine component for subsequent quench hardening, said device comprising: a heating unit for each valve seat, each of said units having a fixed multi-turn primary winding having a central opening with an axis generally perpendicular to said turns and a given axial length; a carrier having first and second longitudinally spaced portions, a single turn sheet type secondary adjacent said first portion and having a central axis generally coinciding with said axis of said primary winding, a single turn inductor adjacent said second portion and having a central axis generally parallel with said axis of said primary, and leads electrically connecting said secondary and said inductor; means for selectively shifting said carrier generally along said axis of said primary winding between a first position and a second position with said inductor magnetically coupled to the valve seat associated with said unit at a desired spacing and with said secondary within said primary winding whereby energizing of said primary causes inductive heating of said valve seat; and, said carrier including a third portion spaced from said second portion on the side opposite to said first portion and a locator means fixed onto said third portion and movable with said inductor, said locator means having an outwardly protruding nose coacting with a bore in said component and concentric with said conical surface for centering said inductor with said valve seat surface associated with said unit when said carrier is in said second portion.

3. An induction heating device as defined in claim 1 wherein said inductor is only slightly spaced from said secondary.