US2131953A - Method of making valves - Google Patents

Description

Oct. 4, 1938. R. JARDlNE :2,131,953

METHOD OF MAKING VALVES Filed 0G17. 14, 1951 IIIIIIIIAI l Patented Oct. 4, 1938 PATENT OFFICE METHOD oF MAKING vALvEs Robert Jardine, Detroit Mich., assignor, by mesne assignments, to Eaton Manufacturing Company, Cleveland, Ohi

o, a corporation of Ohio Application October 14, 1931, Serial No. 568,771

2 Claims.

'Ihis invention relates to valves and more particularly to the poppet type of valve used in internal combustion engines.

One object of the invention is the provision of a valve having a hollow steel head portion filled with material such as copper having superior heat conducting properties.

Another object of the invention is the provision of a valve having a steel shell portion formed by swaging the steel when filled with a ductile material.

Another object of the invention resides in the method of making a valve in which a steel bar is drilled, the hole being subsequently filled with a ductile heat conducting material, the lling material being swelled out in the valve head by a forging operation to provide a hollow steel head having a filling of the heat conducting material.

Other objects and advantages of the invention will be apparent from the following description, the appended claims and the accompanying drawing, in which Fig. 1 is a longitudinal cross-sectional view of a valve formed in accordance with the present invention;

Fig. 2 is a cross-sectional view of the valve body during its course of manufacture;

Figs. 3 and 4 are cross-sectional views Vshowing the head end of a valve at diiferent stages of a modified method of procedure; and

Figs. 5 to 9 illustrate different steps in the course of construction of a valve in accordance with another modification of the method of procedure.

Referring more particularly to the drawing by reference numerals, Ill designates generally a hollow valve adapted to be used in internal combustion engines, and especially adapted for use as an exhaust valve. In such type of valve it is desirable to conduct the heat rapidly from the valve head to the valve stem portion so that the operating temperature of the valve head is reduced. In accordance with the present invention, the valve comprises a hollow steel shell II, containing a lling I2 of a ductile material having superior heat conducting properties. As shown in Fig. l the filling I2 is flared outwardly within the valve head and fills the chamber provided in the valve stem, the head portion of the filling being of substantially mushroom shape and being encased or enclosed in the hollow steel valve head shell indicated at I3. Since the filling I2 is flared out within the valve head, there will be a comparatively rapid transfer of heat from the outer steel shell of the head, the intimate contact or bond between the filling I2 and the steel shell providing for the effective transfer of heat so that the heat may be conducted down to the valve stem and transferred to the valve guide.

In the construction of the Valve, a steel bar I5 shown in Fig. 2 preferably having one end IB of considerably greater diameter than the comparatively long and thinner end Il, is drilled so as to provide the hole I8 extending from one end part way through the bar. This hole is then filled with a plug I9 of copper or other suitable material of sufficient ductility so as to be adapted to the subsequent forging operation, and that has superior heat conducting properties. The filling I9 is preferably applied in the form of a bar which is forced within the hole, the length of this filling material being preferably somewhat shorter than the length of the hole so as to provide a small space 20 at the outer end of the steel bar, as shown.

The end I6 of larger diameter is then forged so as to provide a valve head of substantially mushroom shape, the forging operation serving to force the steel into the space 26 and close this space while at the same time radially expanding both the copper filling and the steel shell portion to provide a hollow steel head having the lling of copper as shown in Fig.V l. If the space 20 is not completely closed by the steel any small openings may be lled by welding. During the forging step, the copper filling of the valve head is intimately associated with or bonded or tted to the steel shell to provide for the effective conduction of heat from the shell to the copper. The heat may therefore be rapidly conducted away from the head and down to the stem portion of the valve during operating conditions, even though the steel shell is an alloy particularly desirable for withstanding the high operating temperatures and the attacking gases that are present in the engine fuel or products of combustion.

In accordance with the structures shown in Figs. 3 and 4, the valve head 2l comprises the steel shell 22 entirely enclosing and encasing the filling 23 of copper or the like, the copper filling being flared out in the valve head to provide for the eective heat transference from the valve head to the valve stem. The steel shell of the valve 2| may be formed by drilling a steel bar 24 almost but not quite down to the larger end 25, this end of the valve being subsequently forged after inserting the bar 26 of copper or similar filling material. The steel shell of the valve head is thus of one-piece integral construction entirely and perfectly sealing the copper filling within it. The stem may of course be machined and finished in any desired manner. When used with the copper filling the Yspace within the valve head and stem, the effective heat transfer during operating conditions is provided for. However, if the copper filling is removed after the valve head isV forged, in the manner more fully set forth and claimed in my co-pending application, Serial No. 568,770, filed on even date herewith, the forging of the head when filled with copper is particularly advantageous, providing inV a simple way forY a steelshell formation of the desired wall thickness.

In accordance with the steps shown in Figs. 5 to 9, the valve is made ina slightly modified manner. 23 designates a steel bar, that is provided with the bores 29 and 30, preferably produced by drilling the bar part Way from one end to the other. Between the two bores 29 and 3D there is a frusto-conical or tapered surface 3|. A filling of copper or other suitable material is then applied, this filling being suitably shaped so as to fit within both bores, and having a tapered or frusto-conical surface 33 that fits Ywith the surface 3l in thebar.v There is an upstanding ring 34 of steel projecting up above the top of the filling 32, and this ring is then forged over and around the filling 32 so as .to shape and Yclose this end of the filled bar substantially as shown in Fig.v 7. The upper end or closed portion of the filled bar may then be flattened by a suitable forging operation so as to provide a fiat circular end 35, and thelower end of the bar is then swaged .or forged so. as to reduce its diameter and form a stem 36 as shown in Fig. 8, curved outwardly at its upper end as shown at 3l. The valve head is then forged, being coined to the shape shown in Fig. 9, this forging step expanding the copper and the outer steel shell in Whichthe copper is enclosed so as to provide a substantially mushroom shaped copper filling 38 in the steel shell 39 of the valve head which entirely encloses it and which is'in close fitting or bonded engagement with it by reason of the forging operation, providing for effective heat transfer from the valve head to the valve stern. In accordance with the method just described the valve stem and the valve seat can then be ma-v chined and any necessary or desirable heat treatments given.

While the methods herein described, and the form of construction produced thereby, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise methods and form of construction, and that changes may be made in either without departing from the scope of the invention which is defined in the appended claims.

What is claimed is: v,

1. The method of making a valve of the class described comprising forming a chambered piece of steel, with continuous sides, rounded and im- Aperforate at one end and open at the other end,

providing a counterbored passage of larger diameter at the open end than at the closed end and with tapering sides joining the passages of different diameter, making a metal core which is larger in cross-sectional area at one end than shaped core encased in steel at the head end of the valve, and elongating the other end into a Valve stem in which the core is enclosed by the steel throughout its length.

2. The method of making a metal filled poppet valve comprising drilling a piece of steel to provide a piece with continuous sides and imperforate at one end and open at the other end, drillingan enlarged axial' passage at the open end of the steel piece of larger cross-sectional area than the passage adjacent the closed end of the'piece and tapering the adjacent ends of the passages from one to the other, forming a metal core of good heat conductivity, 'having rounded ends and larger in'cross-sectional area at the one end than at the other to fit within the chamber and axial passage and fitting the same within the chamber and the axial passage to leave the open end of the passage unfilled, heating the steel piece and forging'itsV terminal or open end so that it is rounded over the end of the core, forging said parts to flatten said terminal end and to elongate the other end of the composite steel piece and core into a valve stem in which the core is enclosed throughout its length in the stem by the steel piece, and forging the fiattened terminal end of the valve to increase the diameter of the steel and the core at the head end of the valve and provide a mushroom shaped core encased in steel.

ROBERT JARDINE. Y

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