US2055342A

US2055342A - Method of making valve tappets

Info

Publication number: US2055342A
Application number: US726041A
Authority: US
Inventors: Schneider George
Original assignee: Wilcox Rich Corp
Current assignee: Wilcox Rich Corp
Priority date: 1934-05-17
Filing date: 1934-05-17
Publication date: 1936-09-22
Anticipated expiration: 1953-09-22

Description

Sept. 22, 1936. G. SCHNEIDER METHOD OF MAKING VALVE TAPPETS Filed May 17, 1934 5 w R 5. 5 fimmw m llllllllrl & m M .M .H yr 6 r w MM w ,m & E H

Patented Sept. 22, 1936 2,0553

* UNITED STATES PATENT OFFICE- METHOD OF MAKING VALVE TAP-PETS George Schneider, Saginaw, Mich, assignor to Wilcox-Rich Corporation, a corporation of Michigan Application May 17, 1934, Serial No. 726,041

6 Claims. (01. 29- 1561?) My invention relates to the construction of is not fragile or easily machinable, for the wear valve tappets which are used in internal combusportion of. the head and attaching it by welding tion engines to transmit the thrust of the valve and then by forging operations to a material operating cams to the fuel intake valves and to that is more easily forged and machined and the exhaust valves. These devices require a hard which is preformed, in such manner that the head 5' wear-resisting face for contacting the cam and material is not greatly deformed in the forgingalso a face which is not brittle or easily fracoperation while the body material is deformed tured. Heretofore it has been customary to conand upset to a greater degree to provide strength struct tappets of a steel body member and a cast in the region of strain adjacent its joint with the iron head or wearing face for contact with the head portion, to broaden its bearing upon and 10 cam. Chilled cast iron provides as good a wearcontact with the head portion, and to strengthen ing surface as is known but it has the disadvanthe parts adjacent the joint.

tage of being more fragile and brittle than steel. Another object is to provide a method of tappet The increase of engine speeds and valve loads construction of, which a large part of the forging 5' have made it necessary and desirable to provide a is eliminated, permitting the use of less forgetappet construction in which the head member able and better wearing head materials.

has practically comparable wearing qualities to Another object of my invention is to provide a chilled cast iron but isstronger and less subject method of tappet construction wherein a preto fracture by impact. Various steel co-nstrucformed head is joined and fitted to a body initially tions have heretofore been proposed, among them by a welding operation which provides the main 20.

the construction wherein apiece of relatively hard bond between two parts and then by a forging steel is attached to a solid rod of relatively soft operation which accomplishes simultaneously the steel of the same size and the combined article extrusion of a portion of the head portion and the is then forged to enlarge the head member to the upsetting of the body portion to broaden its condesired size and to spread the desired hard steel tact and bearing upon the head portion and to 25,.

facing material over the surface of the enlarged thicken and strengthen its wall structure in the head member which is usually chiefly composed region where the greatest stresses are applied to of the softer steel. This requires a considerable the article in use.

amount of forging and acomplete deformation Another object is to lessen the cost of manuand reworking of the hard steel facing material facture of such articles. 30;

with the consequent development of flaws and With these and other objects in w, y inequalities of distribution which are likely to vention consists in the combination, arrangement occur in such forging operations. and construction of the various parts of my imone bject of my invention is to provide a, tapproved device and the method of making the same pet construction wherein metal or alloy having described and Claimed in pa y 3 predominant wear and impact resisting qualities Specification and Shown in the drawing. in wh ch! but which is somewhat difficult to forge or ma- Fi re 1 is a V w in elevation and p r ly in chine because of those qualities and characteris- Section Of the y portion of the pp t ade a0- tics may be utilized as a facing or head member cording to y invention- 40 for the tappet and attached to and combined with 2 is a p View Of the head portion f the the preformed body portion of a more easily matappet e according to my invention. chined and forgeable metal without the necessity 3 is an edge V ew in elevation of the head of re-working or reforming the facing or head portion Shown in member to any substantial degree. Fig. 4 is a view partly in elevation and'partly Another object of my invention is to provide a in section Of the body portion and head portion 45-.

method of construction in which the wearing assembled in a welding 11% for he n al weldface or head member of wear and impact resisting Operation ing material is joined to a body portion of more Fig. 5 is a View p y in elevation and partly easily machinable and forgeable material in a in section of the body and head portions mounted manner that diminishes substantially the amount in the welding fixture showing their relation to 50. of forging or working of the more diflicult head one another after the welding operation has been material. 7 completed. v

Another object of my invention is to provide a Fig. 6 is a view in elevation and partly in secmethod of tappet construction by providing a pretion showing the tappet mounted in a forging fixformed disc-of the wear resisting material which ture preparatory to the forging operation which accomplishes the simultaneous extrusion of the head portion and upsetting of the body portion.

Fig. 7 is a fragmentary elevational View partly in section showing the tappet in the forging fixture after the forging operation has been com- 7 pleted.

tubular member l preferably steel or alloy there-.

of preformed by machining and provided with a thickened flanged end portion 2, the upper'surface of which is beveled to provide a point contact portion 3. g The underside of the flange 2 is also slightly beveled as at 4. The lower end of the tappet is provided with a reduced bore 5, as shown in Fig. 10, which is internally threaded to receive an adjusting screw or stud of the usual type which may be turned in or backed out of the tappet to adjust the clearance between the end of the tappet and the valve stem of the engine, not shown, according to usual practice as well understood by those familiar with the art. The lower exterior end of the body I is reduced in outside diameter as at 6 and provided with wrench flats 7 on opposite sides thereof for receiving a wrench in the operation of manipulating the conventional adjusting screw or stud which is not shown. This body I is made of relatively easily machinable material such as is customarily used for this rp l 1 I In Figs. 2 and 3 are shown the head portion of l the tappet which consists of a preformed annular disc 8 of impact and wear-resisting metal or alloy. Standard Sp cification S. A. E. 52-100 steel being one suitable material. This disc may be punched from sheet stock or cast or otherwise formed to substantially the desired ultimate sizeof the tappet head which is indicated by the full lines in Figs. 2 and 3. This disc, however, mat be made smaller than the ultimate head size, and thicker, as indicated by the dotted lines in Fig. 3, which will be spread and thinned in the forging operation as hereinafter explained.

The body and the head piece having been preformed as described, the method of securing them together consists in first mounting the body memher I in a hollow welding electrode Band then positioning the head member 8 on the flange end 2 of thebody with the underside, of the disc 8 in contact with the point or ridge 3 formed on the upper surface of the flange 2. The opposite welding electrode I0 is then brought against the upper surface of the head member 8 and the welding circuit closed. Upon the, closing of the circuit,

the current passes through the point contact 3 between the head member 8 and the. body member l and melts and welds the metal of the parts together at this point. The welding is continued until the welded joint between the head member 8 and the body I extends substantially across the'widest portion ofthe flange 2 as shown in Fig. 5. This is in the nature of aprogressive welding operation and is carried out in the manner described to efliciently utilize the welding current and to secure as broad a homogeneous weld between the parts as is possible withthe possible area of contact between the two. It is desirable to provide fora point contact between the head and the body member in order to secure this weld on account of the fact that the shape of the flange 2 on the body member willnot permit the positioning of the electrode 9 in such a manner as to provide a uniform initial flow of current between a flat upper surface upon the flange 2 and the flat underside of the headmember 8; this because of the well known fact that the current will take the shortest path between the electrodes and there would be an uneven distribution of heat produced between the contacting parts of the head and body members, thus making for a nonuniform and very likely defective weld. By pro viding for the point contact between the two members the heat is initially concentrated in the form shown in Fig. lat the point contact between the inner edge of the flange 2 and the head member '8. This melts the metal of the flange 2 with comparative rapidity and of course pro-heats the adjacent parts of the flange 2 and the head;

member 8 so that when the two parts comes into full contact, as shown in Fig. 5, a substantially;uni-. form weld has been accomplished across the Wld'.

est portion of the flange member 2.. This may also be accomplished with themodifled form of; the body shown in Fig. 8, wherein the flange 2 isso formed that the point of contact with the head member 8 is at the outer edgeof the flange 2.

flange shown in Fig. 8, although themost desirable practice is to so form the flange that the point of contact is at or adjacent the inner edge of theflange. accepted weld by so forming the flange 2 that the pointed contact between it and the head member 8 will initially occur ata point intermediate the edges of the flange 2. This, however, may neces-v sitate additional machining operations which are.

undesirable because of cost,

After the head member 8 has been welded to the body member I, as described, the assembledarticle is reheated to a desirable forging temperatureand placed in thedie member I2 shown in Fig. 6. This die member is provided with a lon gitudinal cavity of a size adapted to closely receive that portion of the body I below the flange 2 and with an enlarged upper cavity of a size corresponding to the ultimate desiredsizeof the head member 8. The lower surface of this'upper cavity is inclined toward the reduced cavity which receives the lower part of the body l, the inclina-.,

tion being at a degree slightly less than the bevel 4 on the underside of the flange 2. The inclination of this die cavity may be regulated to cone trol to some extent the direction of displacement:

work the initial weld between the head 8 and the This strengthens the .Weld as Well as flange 2. broadens the bearing between the head 8 and the flange 2.

the tappet body immediately adjacent and bem t t e head m mb t ther ntwhere e Anv acceptable weld may be obtained with the form'of:

It is also possible to obtain an:

The forging operation also extends the. support of the flange 2 outwardly toward theedges of the head member 8 and thickens the walls of greatest strain occurs in use, thus substantially strengthening the construction. The forging operation also, simultaneously with the upsetting of the body flange 2, causes an extrusion of the metal of the head member 8 into the tubular end of the body member 2, as shown in Fig. '7. This extrusion extends downwardly through the opening between the thickened portions of the walls of the tappet body adjacent the head and in close engagement therewith and provides a solid reinforcement for the walls of the body at this point which, as before mentioned, is the point of greatest strain and use. The amount of this extension may be controlled as desired by controlling the travel of the punch. The purpose being accomplished when an embracing engagement between said members is obtained around the welded joint.

If it is desired, the head member 8, as previously mentioned, may be preformed to a disc of a greater thickness and less diameter than the ultimate size of the head, as shown by the dotted lines in Fig. 3, and by the dotted lines in Fig. 6. The process of welding this thickened head to the body is the same as previously described, and the process of forging is also the same, except that the forging operation instead of merely extruding the metal of the head member into the open end of the tubular body I will also spread the metal of the head member laterally to the ultimate size of the head which is the size of the cavity in the die member 12. It may be desirable to use this smaller form of disc on account of the size of stock readily available from which the discs may be punched and also for the purpose of spreading the flange 2 of the body member in the forging operation so that it will have a somewhat greater area of contact with the underside of the head than in the construction where the preformed disc of ultimate size is used. The ultimate construction of the tappet will be the same as shown in Fig. 10, except that the flange 2 may extend slightly closer to the outer edge of the head 8.

After the forging operation has been completed, the tappet is complete except for finishing operations such as tapping the reduced bore 5, final heat treatment, rough and finish grinding the stem or body portion of the tappet, and finish grinding the face of the head 8. The forging operation may be accomplished cold or with such heat as remains in the parts after the welding operation, although it is preferable to re-heat the assembly before forging.

Formal changes may be made in the specific embodiment of the invention described without departing from the spirit and substance of the broad invention, the scope of which is commensurate with the appended claims.

I claim:

1. The method of making a tappet which comprises preforming a tubular metal body portion and providing a thickened flanged end thereon, superposing a head of relatively harder metal in the shape of a preformed and flat disc on the thickened flanged end of said tubular body and welding the same together, and then forging the welded assembly of head and body to simultaneously re-work the welded joint and extrude part of the head member into the tubular opening in the body member to reinforce the walls of said body member beneath the overhanging portion of said head member.

2. The method of making a tappet comprising applying a preformed disc of hard steel and of substantially uniform thickness to a preformed tubular body member of relatively softer steel and having a thickened flanged end, by welding said disc to and over said thickened flanged end of said body, and then forging said assembled head and body to broaden the bearing and joint between the two and simultaneously extrude part of the disc into the tubular opening in the end of said body, and in tight engagement with the inner walls of said body beneath said head.

3. The method of making a tappet comprising applying a preformed disc of hard steel and of substantially uniform thickness to a preformed tubular body member of relatively softer steel and having a thickened flanged end, by welding said disc to and over said thickened flanged end of said body, and then forging said assembled head and body to broaden the joint between the two and simultaneously extrude part of the disc into the tubular opening in the end of said body and to upset and thicken said body wall beneath said flange portion to force a part of said thickened portion of said body to the inside of the walls of said body member to close bearing with the extruded portion of said head, thereby solidifying the upper end of said tubular body member beneath said head.

4. The method of making a tappet which comprises preforming a tubular body member of relatively soft steel and providing a pointed flanged end thereon, superposing a flat disc of relatively harder steel having wear-resisting qualities comparable to those of white cast iron but having greater resistance to fracture under impact than cast iron on said pointed flanged end of said body, applying localized Welding heat to the points of contact between said disc and said body, and maintaining the same until the said disc and body are welded together over substantially the greatest transverse dimension of the flange on said body, and forging the assembly to re-work the weld and broaden the bearing between said disc and body in both directions transverse to the major axis of said body walls, and simultaneously to extrude part of the metal of said disc into engagement with said tubular body.

5. The method of making a tappet comprising preforming a tubular metal body member and forming an annular flange on the end thereof having a pointed upper extremity, superposing a flat disc of relatively harder but less easily machinable and forgeable metal than that of said body member upon the'pointed extremity of said flange, electrically welding said disc to said flange by applying one electrode on the underside of said flange and another electrode on the top of said disc, and maintaining said welding contact until the weld between said disc and said flange extends substantially over the width of said flange.

6. The method of making a tappet comprising preforming a tubular steel body member, superposing a flat disc of relatively harder steel and of substantially the ultimate desired head size upon the open end of said tubular body and welding the same thereto, and then forging said assembly to simultaneously extrude a portion of said head member and upset a portion of said tubular body member into embracing engagement around said welded joint.

GEORGE SCHNEIDER.