US2193088A

US2193088A - Poppet valve blank and method of making same

Info

Publication number: US2193088A
Application number: US190220A
Authority: US
Inventors: Charlton George
Original assignee: Eaton Manufacturing Co
Current assignee: Eaton Corp
Priority date: 1937-06-28
Filing date: 1938-02-12
Publication date: 1940-03-12
Anticipated expiration: 1957-03-12
Also published as: US2183254A; FR836333A

Description

March 12, 1940. CHARLTON 2,193,088

POPPET VALVE BLANK AND METHOD OF MAKING SAME Original Filed June 28,1837

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A TT0RNEY 59% y/zm.

Patented Mar. 12, 1940 g V r 2,193,088

PATENT OFFICE POPPE'i" VALVE BLANK AND METHOD OF MAKING SAME George Charlton, Battle Creek, Micln, assignor to Baton Manufacturing Qhio, a corporation of Ohio rlglnal application June as, 1937, Serial No. 150,771. Divided and this application February 12,1938, Serial rim-190,220

Company; Cleveland,

iiClaiins. (ciao-156.7)

. This invention relates to poppet valves and to t method of making the same and is particularly adaptable for use in connection with poppet .valves of the type employed ininternal combustion engines and to those types thereof which are hollow and contain sealed therein ,a mass of coolant material. This application is a division of my application for Letters Patent of the United States filed'the 28th day of June, 193.7"for improvements in Valve structure and method of forming, Serial No. 150,771. Objects of the invention include the provision of a new and novel method of forming a hollow poppet valve; the provision of. a novel method of making a hollow pop t valve formed from aplurality of independently formed parts; the provision of a method of making hollow poppet valves in whichrthe head portion and the stem portion of the valve are independently formed and are thereafter joined by internally distributing 'a mass of molten metal under the efiects of centrifugal force over the Joint between them; the provision of a methodof making a hollow p ppet valve in which the head portion of the valve is independently formed from the stem portion thereof and both portions thereof are hollow, so forming the stem portion as to predetermine its position with respect to the head portion when initially assembled thereto, temporarily securing 30 the two portions together in sealed relationship, and then distributing a mass of molten metal to the joint between the parts under the effects of centrifugal force, and thereafter machining the structure to bring it to its completed size, shape and contour; and the method of making a hollow poppet valve as above described in which the molten metal employed for bonding the two parts together is" initially introduced into one of the parts in solid state and both parts are thereafter heated to a sufllcient temperature to effect a melting of the bonding material without effecting a melting of the parts. Further objects include the provision of a novel form of poppet valve blank; and the provision of a poppet valve blank constructed of a plurality of separately formed parts so initially formed as to predetermine their assembled relationship when assembled together.

, The above being among the objects of the present invention the same consists in certain novel features of construction, combination of parts, and step or steps of operation to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illus trates suitable embodiments of the present invention, and in which like numerals. refer to like parts throughout the several different views,

Figure 1 is a vertical sectional broken view 5 taken axially through the stem portion of a. valve constructed in accordance with the present invention as initially formed independently of the head portion and before its assembly to the head portion; JFig.-2 is an axial view of the valve stem shown in Fig. I-taken as on the line 2 -2 of Fig. 1;

Fig. 3 is a vertical sectional view taken axially through an independently formed head portion of a valve to be constructed in accordance with iii the present invention prior to the assembly of the stem portion thereto;

Fig. 4 is-a fragmentary sectional view'taken axially through the parts and illustrates the stem portion shown in Fig. l assembled to the head 20 portion shown in Fig. 3.and welded thereto to temporarily seal' the joint between them and maintain them in a predetermined position, a mass of the material, which is to be employed to bond the two parts together being shown as 28 contained within the bottom of the hollow interior of the stem portion;

Fig. 5 is a view similar to Fig. 4 after the bonding operation hasbeen completed;

Fig. 6 is a partially broken vertical sectional view taken axially through a completed valve formed in accordance with the disclosure in the preceding figures;

Fig. ,7 is a fragmentary vertical sectional view taken centrally through the head portion of a valve similar to that shown in Fig. 6 but including certain additional features;

Fig. 8 is a view similar to Fig. 4 but illustrating a modified form of construction; and,

Fig. 9 is a fragmentary vertical sectional view 40 taken axially through a completed valve formed in accordance with the disclosure in Fig. 8.

The invention may be employed for integrally uniting a plurality of parts to form an integral valve structure. In such case the plurality of 45 parts are so constructed and arranged as to provide a reservoir for a granular alloy material and the parts are so constructed and arranged that upon melting of the material and spinning of the assembly the alloying material 'will become dis- 5o tributed in the joint between the parts and after solidifying will form all of the parts into a unitary' valve structure. Accordingly, the invention is particularly valuable in connection with the forming of hollow valves and particularly hollow u .a hollow head portion and an independently formed hollow stem portion the character of both of which is such as to permit them to be easily and quickly machined. The stem portion insuch case in initially formed in such a manner as to provide a space adjacent the Joint between the parts when assembled together for receiving the alloying or other material which is to form a bond between the parts. The stem portion and the head portion are then assembled together, temporarily secured together in assembled rela tlonship and the joint between them temporarily sealed, the bonding material is introduced into the stemv portion and then both portions are heated to a temperature sufllcient to melt the bonding material without causing a melting of the head portion and the stem portion and while the bonding material is in molten condition the assembly is subjected to a spinning operation whereby the molten material under centrifugal force is distributed to the joint between the parts where it bonds itself to both parts, seals the joints between the parts and permanentlysecures the parts together in such a manner as to effectively prevent leakage or escape of a contained cooling medium when employed from the interior of the" valve during operation of the valve under high temperatures.

. It has heretofore been suggested that hollow valves intended to containsodium or other cooling agent be formed byv constructing the valve in 'two or more pieces each of which may be relatively easily machined, and thereafter welding them together by known methods as, for instance, electric or' gas welding, but this practice has never become, commercially practicable for the reason that it is commercially impracticable in production to produce valves in this manner without an unduly large percentage of scrap, and the final product, even where the weld appears perfeet, too frequently develops cracks in the welded zone which permits escape of the contained cooling medium. Because of these reasons such types of valves as have heretofore been sucully 1 preferred methods of rused commercially and produced in we." rcial quantities have each been produced from a le piece of steel by boring it out of a solid and sng down the portion desired for the s a to suitable dimensions, which obviously requirw an are large amount of careful j and expensive work in its production. th emplo of the present invention the t '9. on screw maed tnthe ri is oi sucha nate the constructed in accordance therewith, d rei'errin'g first to the construction illustrated in 1 Figs. 1 to 6,, inclunve, the independen .io

stem portion of the valve is illustrated in Figs. 1 and 2. In these figures the stem portion is indicated generally at It ascomprising a hollow cylindrical body having a bore I l, a closed end l2 and an open end it. The diameter of the 5 body III over the greater portion of its length is slightly greater than-the outside diameter desired in vtlie finished valve stem. The end I. is initially made of a materially, greater diameter as illustrated so that during the flnal steps of operation 10 this end may be swaged down to bring the outer diameter commensurate with the diameter of the main body portion of the stem and thereby constrict the bore of the stem in the manner illus-:

trated at It for reasons which will hereinafter be more apparent; On its outer face the closed end it is provided with an axial projection II the purpose of which will hereinafter be apparent and the side walls of the main body portion III of the stem immediately above the end wall I! are pro- 20 vided with one or more radial apertures I! therethrough.

The head portion 20 of the valve which is shown in Fig. 3 is initially formed as a short lindrical block of slightly greater diameter than 25' of the length of the bore 22 as shown.

- The above portions of thevalve and DQ111011. larly the head portion 20 may be made from any suitable steel or steel alloy such as is commonly used for the valves of internal combustion 6o engines. Where the valve is to be used as anexhaust valve these portions of the valve are. preferably of a type of steel that will stand the high temperatures and corrosive action of the exhaust gases and in such case it may be desir- 5 able to employ analloy generally known to the trade as silichrome X'-142having-'approximately the following analysis. This alloy has a melting point of approximately 2650 F. a

Carbon am to nganese 320% maximum chromium--. 13.00% to 15.00% Nickel 13.00% to 15.00% COD $097 t0 i 1.70% s.00

m mm .il3% maximum Sulphur i I? iron Remainder Another suitable oy in use in the m an 00 and stem it is as follows, the percen fiven being approximate.

of 39 0.1 u, 2604? F. *1 first of these alloys is mown as an austenitic type of alloy, and does not become hard upon heating and quenching. -The last described alloy is an m a type of go all a e;-

alloy; that is, it becomes hard upon heating and quenching. These two alloys areset out merely as illustrative of the various types of material that may be satisfactorily employed for the head 20 and stem l0.

As willbe apparent to those skilled in the art the stem I and head 20 are of such character that they may be readily formed from bar stock on screw machines or the like in a quick, easy and economical manner. On the other hand they may be formed in any suitable or desirable manner and the head in particular formed by suitable initial forging or other operations. In any case the hollow interiors of both the head and the stem portions will be readily available to easy machining operation so as tobring their internal dimensions to accurate conformance with a preapparent that the projection l1 serves as a means for locating the stem l0 in axially desired relation with respect tothe head 20. Accordingly, the length of the projection Il may be so governed as to'obtain any desired relationship between the head and the stem but in the particular instance shown this is such as to bring the radial openings l8 in the stem I 0 to radial alignment with the annular groove 26 in the head 20. In the figures the amount of clearance between the outer surface of the stem l0 and the bore 22 of the head 20 is exaggerated in order to better illustrate the construction, it being understood that in actual practice the fit between these parts will be sufliwill not be of excessive thickness. .In some cases at least it may be found satisfactory to so control the clearance between these parts that it will effect a capillary action on the bonding material tending to draw the bonding material throughout the entire area of the joint between the parts. However, due to the spinning operation hereinafter described it will be understood that such capillary attraction of the bonding material is not entirely relied upon to obtain the proper distribution of the bonding material throughout the area of the joint.

The parts being assembled as illustrated in Fig. 4 they are then welded together as at 28, preferably by gas or electric welding, not only to-temporarily secure these parts together in assembled relationship but also to seal this end of the joint between the parts against the escape of the bonding material during the stepof distributing this material between the parts.

When the parts have reached the stage of assembly illustrated in Fig. 4 a mass of material 30 which it is desired to employ as the agent for bonding the two parts together is then deposited in the bottom of the stem portion ID as illustrated in Fig. 4. The material 30 will usually be of a composition which will be determined to a great extent by the use to which the valve is to be put. Where the valve is not to be employed in internal combustion engines and is not to be employed for any use which will regiven as is follows:

*quire it to withstand anything above normal room temperatures, or relatively low temperatures, it may be hard solder, spelter or the like. Where higher temperatures are to be encountered by the valve any suitable metal or alloy capable of being bonded to the head 20 and stem ill in molten condition and of such a character as to stand the temperatures to be encountered without melting or materially weakening its structure may be employed. Aluminum bronze is an example of a material that may e employed under such conditions. Where the valve is for an internal combustion engine and particularly where it is of the sodium or other internally cooled type requiring it to withstand relatively high temperatures, and the stem and head of the valve are formed from a suitable steel or steel alloy such as those heretofore specifically set out, a suitable alloy having a melting point lower than that of the head and stem of the valve but nevertheless approaching the melting point of these parts will usually be found preferable. An alloy of the following composition has been found suitable for use in such case. I

. Per cent Carbon l 0.76 Manganese 0.14 Chromium 9.04 Silicon 0.63 Nickel 33.17 Boron 1.87 Balance Principally iron The melting point of this alloy is approximately 2075 F. With this alloy spinning can readily be done between 2150 F. and 2200 F. and it may be employed where the head and stem portions of the valve are made of any suitable type of steel having an ordinary melting point.

Another alloy suitable for use as the material 30 where the head and stem portion of the valve are formed from either ordinary steel or of .a steel alloy such as either of the first two analyses Per cent Carbon 0.38 Silicon 0.23 Chromium 14.53 Tungsten 18.08 Boron 3.5 Balance Principally iron The melting point of this alloy is approximately 2130 F. and successful spinning has been done with it at 2250 F. I

One type of alloy whichismarketed under a well known trade-name isalso adaptable for use as the material 30; Such material is manufac tured in diiferent grades any one of which may 7 be found suitable for use as the material 30 and.

as indicative of the various grades of such 'mate rial the approximate analysis of one grade here set out.

The melting point of this particular alloy is approximately 2350 F. Other grades of the same type of alloy contain thesame elements but in difierent proportions than thosestated, the

characteristics of the final product what varied thereby.

The amount of material 30 that is placed withbeing somein the stem of the parts as brought to the assembled-condition illustrated in Fig. 4 is preferably only slightly in excess of that required to effect the desired bond between'the parts, a slight excess being provided to insure the completeness of this bond and the bulk of the excess which escapes into the pocket 24 is evenly distributed around the periphery thereof in the final product and offers no particular problem, nor is its presence particularly undesirable.

While in the broader aspects of the present invention the stem Ill, and head 20 after being welded together as at 28 in Fig. 4 may be brought up to a temperature approaching or in excess of the melting point of the material 30 before the material 30 is added and in such conditions the suitable flux if thought necessary, or in a neutral Preferably the temperature will be approximately 100 degrees in excess of the melting point of the material 30. In the absence of a furnace or other heating device not capable of heating the assembly up in a neutralor non-oxidizing atmosphere, a suitable material may be introduced into the interior of the hollow stem prior to the heating operation to prevent oxidization of the interior surfaces thereof during such operation. Alcohol is an example of such material and in such case it will be preferable to temporarily substantially close the open end of the stem during the heating operation so as to insure the maintenance of the non-oxidizing atmosphere within the hollow interior of the parts.

As soon as the parts i0 and 2i) and the material 30 have been brought to a sufficient temperature to effect a melting of the material 30, the assembly is then removed from the heating device and is immediately subjected to a spinning operation about the axis of the parts. This spinning operation places the molten material 30 under a centrifugal force which drives the material 3B radially outwardly through the openings i8 and into the joint formed by the bore 22 and the opposed outer face of the stem it, filling the groove 25 and causing this material to be intimately bonded to both the stem l0 and head 20. In some instances where the fit between the parts permits, the capillary attraction aiforded by the fit as previously mentioned may aid in the distribution of the material 30 throughout the area of the joint. Also a portion of the molten material 3% will be discharged during the spinning operation into the pocket it where it will be distributed to the radially outer wall thereof as indicated at 32 in Fig. 5, this, of course, being unnecessary but occurring only because of the precaution taken to insure sufiicient material 36 in all cases to complete the bond at the joint between the parts. Some of the material 30 will remain in the openings 58 and it will, of course,

completely fill the annular groove 26 so that those portions of the material 36 remaining in the openings l8 and received in the groove 2% will serve to provide keys formed from the material laieaoae a tending to lock the stem lo and head against axial separation by a mechanical interconnection as well as by the bond of the material 30 to these parts.

Although it will be found that a most satisfactory bond between the material 30 and the stem and head 20 will occur even though the ma- 4 terial 30 has a melting point materially lower than the melting point of the stem Ill and the head 20, where the material 30 is formed from the higher melting point alloys, the composition of which has been specifically set out above, the temperature to which it is necessary to heat the parts to obtain the melting of the material 30 and the desired fluidity thereof for the spinning operation will often cause a sweating of the sur-- faces of the stem l0 and head 20 as commonly occurs preliminary to the actual melting of the.

material from which they are formed and where the molten material 30 is distributed to these tual alloying of the material 30 with the material of the stem l0 and head 20 occurs'so that in such case a most permanent and effective bond is established between the stem and the head which not only efiectively prevents any possibility of separation of the parts in service but additionally provides a most effective seal against the escape sweating surfaces it has been found that an ac-" of pressure through the joint between these parts.

This feature is particularly important in connecinternally cooled self-contained coolant types of valves subject to hard usage at elevated temperation with these valvesw'hen they are employed as tures in internal combustion engines and parthe material 30 has been permitted suflicient time to insure proper distribution throughout the joint between the parts and suiilcient time has elapsed to permit such material 30 to solidify. Thereafter the spinning operation is terminated, the assembly is allowed to cool and is then subiected to further operations to bringit to acompleted state. The first of these operations is to remove the end wall I! and projection II. This may be readily done by projecting a drill down the bore ll of the stem l0 and simply drilling out the end wall l2 upon which the projection I! may be readily discharged from the bore of the stem. This operation places the bore ll of the stem ID in open communication with the pocket 24 and the head 20 as illustrated in Fig. 6. The next operation may consist of swaging down the opposite end of the stem l0 as at I 6 previously described to restrict its bore, as illustrated in completed form in Fig. 6, and then the exterior surfaces of the assembly thus provided may be machined to bring it to completed condition and to form a desired seating surface such as 34 on the head 26, during which operations the welded material 28 will usually be removed completely.

It may be noted that it is only when the valve is to be of the internally cooled type and in which the internal coolant is self-contained that it is necessary to constrict the bore at the upper end of the stem it as illustrated, but under such circumstances the restricted end of the stem i0 is then drilled and reamed out ior reception of a tapered pin such as 86. Before insertion of the pin 33 the internal coolant illustrated in Fig. 6 at 38 is introduced into the hollow interior of the valve through the restricted bore in the end of the stem provided for the reception w of the pin 38, the pin 3815 introduced and driven firmly into place,the end of the stem l0 and pin 38 arethen finished off in flush relationship, and a valve stem end portion such as 38 is then welded in placeon the end of the stem over the pin 38. These last precautions are taken to absolutely insure the closing of the corresponding end of the stem In in order to thereafter obviate any possibility of the escape of the coolant 38 therethrough. The finish machiningoperations on the valve may then be accomplished to bring the valve to its completed condition.

The material 38 which is preferably employed as the internal self-contained coolant for the in its initial stages.

valve maybe metallic sodium or other suitable material such, for instance, as disclosed in U. 8. Patent No. 1,670,965, such material being fluid at ordinary temperatures to which such valves are subjected in normal operation of internal combustion engines and which, in being continuously transferred between the stem and head portions of the valve during operation tend to carry the heat away from the head 20to the stem Ill from which it is dissipated by contact with the valve guide (not shown) or other parts in which the stem I0 is commonly in contact.

In Fig. 7 a slight modification of the above described valve is shown. In this construction, inasmuch as the modification involves only a small change in the stem ID, the parts are indicated by the same numerals as employed in Figs. 1 to 6, inclusive, except such numerals bear a prime mark. The head 20 is identical to the head 20 previously described. The only difference in the stem I0 is that the exterior surface of the stem Ill in line with the radially outer ends of the openings I1 is provided with a circumferential groove 40 which lies in opposed relationship with respect to the annular groove 28'. Accordingly, in the final product the material in the grooves 28' and 40 combine to form an annular ring of the material 30 between the in the modification shown in Figs. 8 and 9 no such mechanical interlocking is provided for. The construction shown in Figs. 8 and 9 fs essentially similar to the construction shown and described in the preceding figures. In otherwords,

the stem l0" corresponds with the stem l0 previously shown and described and similarly too it includes an end wall l2" and projection l1" Likewise the head portion 20" is provided with a bore 22" for reception of the stem Ill" and this bore 22" opens into a pocket24". In this case the pocket 24" is of a different contour than the pocket 24 previously described, this being primarily because of the fact that the shape of the final valve head is somewhat different from the construction shown in the preceding figure. The function of the various elements of the construction, the method of assembly and steps of operation to provide the completed valve are substantially the same as that previously described and for that reason it is not believed necessary to repeat them. Neither the head 20" or stem ID" are provided with grooves such as the

grooves

28 and 40 previously described, the bond of the material 30" being relied upon entirely for securing the head and stem against axial separation. One difference, however, may be noted that in the construction shown in Fig. 9 a layer 42 of material which may be equivalent to any of the specific compositions ofmatter set out for the material 30 may be applied over that portion of the head 20" which is to serve as the valve seating surface, the purpose of the material 42 in this case being to provide such valve seating surface that will resist the corrosive and erosive effects of the hot exhaust gases of an internal combustion engine in which the valve is to be employed. The material 42 may be added by applying it to the head 20" by welding it in place in accordance with well known practices or may be applied in any other suitable manner.

Formal changes may be made in the specific embodiment of the invention shown and steps of operation described without departing from the spirit or substance of the broadinvention, the scope of which is commensurate" with the appended claims.

What is claimed is:

1. A valve blank comprising an independently formed hollow head portion and an independently formed hollow stem portion, an end wall at one end of said stem portion, said end of said stem projecting into said head portion to form a joint between them, and said stem portion having openings therethrough adjacent said end wall to provide communication between the interior and exterior thereofwithin the area of said joint.

2. A valve blank comprising an independently formed hollow head portion and an independently formed hollowstem portion, an end wall at one end of said stem portion, said end of said stem projecting into said head portion to form a joint between them, said stem portion having openings therethrough adjacent said end wall to provide communication between the interior and exterior thereof within the area of said joint,

and said head portion having an annular groove therein within the area of said joint.

3. A valve blank comprising an independently formed hollow head portion and an independently formed hollow stem portion, an end wall at one end of said stem portion, said end of said stem projecting into said head portion to form a joint between them, said stem portion having openings therethrough adjacent said end wall to provide communication between the interior and exterior thereof within the area of said joint, and said stem portion having an annular groove therein within the area of said joint.

4. In ,the manufacture of a hollow poppet valve,

' the steps of forming a head portion of a size in excess of the dimensions of the head in the desired completed valve, operating upon said head portion to form a pocket therein and opening. leading into said pocket, separately forming an bonding material having a melting point lower than the melting point of the material of both said portions into said stem, heating said assembly to a temperature suillcient to render said bonding material fluid but less than the melting points of the head portion and stem portion, spinning said assembly about its axis whilesaid bonding material is fluid whereby to centrifugally discharge said material through said hole and distribute it throughout the joint between said portions, continuing said spinning until said material has solidified, and then machining the resulting assembly.

5. In the manufacture of a hollow popp t valve, the steps of providing a hollow head having an opening leading into the interior thereof, inserting a hollow stem having an end wall and openings through the side walls thereof adjacent said end wall into said opening with said'end wall within said head and said openings closed by the walls of said opening, placing a mass of solid material having a lower melting point than that of said head and stem in said stem, heating the resulting assembly to a temperature suflicient to melt said material but insufilcient to melt said head and stem, and then spinning said assembly about its axis whereby to cause said molten material to be discharged through said end wall into said opening with said end wall within said head and said openings closed by the walls of said opening, placing a mass of solid material having a lower melting point than that of said head and stem in said stem, heating the resulting assembly to a temperature suflicient to melt said material but insufiicient to melt said head and stem, and then spinning said assembly aboutits axis whereby to cause said molten masaid stem and to fill the space between said stem and the walls of said opening in said head, continuing said spinning until said material has solidified, and then removing said end wall in said stem.

' GEORGE CHARLTON.

terial to be discharged through said openings in 80