US2093774A - Method of making valves - Google Patents

Description

A. T. coLWELL METHOD OF MAKING VALVES Filed May 20, 1951 g., j Z 1 3 Sept. 21, 1937.

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3 y f F0, w 0 T \j v Patented Sept. 2l, i937 METHOD 0F MAKING VALVES Archie T. Colwell, Cleveland, 0hio, assgnor to Thompson Products, llncorporated, Cleveland, Ohio, a corporation of Ohio Application May 20, 1931, Serial No. 538,785

3 Claims.

This invention relates to the manufacture of valves and in particular to a process for making copper cooled exhaust valves for internal combustion engines.

Temperatures attained in the combustion chambers of automotive engines closely approximate the temperatures to which the metals used in the manufacture of valves are heated in such manufacture. The gases which pass through the 10 exhaust valves maintain the exhaust passageway 15 the metal of the valves.

at a temperature of around 1600 F. for ordinary engine speeds. These gases have a very destructive effect on the valves, causing corrosion and warping and producing a destructive change in Since these gases are directed against a portion of the valves which includes the upper portion of its stem and the lower portion of its head, it has beena problem for valve manufacturers to devise a means of cooling this portion of the valve.

This cooling has been accomplished in several ways, as by providing a shield around this porltion of the valve and by filling Athe interior of the valve with a cooling or high heat conducting means.

This invention relates to the latter type of cooled valve and it is an object of this invention to produce a valve of this type by a method which is inexpensive, expedient and adapted for use in large scale production.

It is a further object of this invention to produce a metallic cooled valve by a method which insures a perfect bond between the metal of the valve and the metallic cooling insert.

It is a particular object of this invention to provide a method of making a metallic cooled valve in which the metal of the body of the valve is shrunk onto an insert metal and welded thereto.

Other and further important objects of this invention will be apparent from the following.

description and appended claims.

This invention (in a preferred form) is illustrated in the drawing and hereinafter more fully described.

On the drawing:

Figure l is a sectional view of a metal blank with a recess drilled therein, used for forming the valve of this invention.

Figure 2 is a sectional View of the blank with an insert therein.

Figure 3 is a sectional view of a suitable form of die blank with a partially extruded valve therein.

Figure 4 is a sectional view of a valve blank after extrusion.

Figure 5 is a sectional view of a valve blank which has been extruded in accordance with a modiiied form of my invention.

Figure 6 is a sectional view of a completed valve.

As shown on the drawing: i

In carrying out this invention, a blank l is formed as by casting. or by cutting a slug from a bar of rolled stock. A suitable recess 2 is drilled in the blank l. The recess 2 is preferably cylindrical and concentric with the blank l extending through one end of the blank and for a substantial distance within the blank.

The blank I is heated to a forging temperature and an insert 3 is forced into the expanded recess 2.

The blank I may be formed of any suitable valve material, such as tungsten steel or nickel chromium steel. The insert or slug 3 is formed of a suitable metal which has a. high rate of heat conductivity relative to that of the metal of the blank. In practice, copper and aluminum have been found to be suitable metals from which to form the insert 3. v

The composite metal blank thus formed is headed or extruded to form the finished valve.

Figure 3 illustrates a suitable die block i for extruding the blank to form the valve. The block d preferably comprises a pair of superimposed members 5 and 6, the top member 5 of which is provided with a recess 'i extending for a considerable distance therein. The inner wall of the recess l tapers downwardly and inwardly and ends in an inwardly curved portion 8 shaped to form the neck of the valve. The recess 'l is preferably slightly larger in cross section than the blank i. The lower member 6 is formed with a long cylindrical recess 9, the inner wall of which is a continuation of the portion of the wall of the recess member 5. The recess S is for forming the stem of the valve. The lower inember 6 is also provided with a passageway i@ through which a suitable temperature controlling uid may be passed.

The heated blank is forced through the aperture in the extruding block to form the blank into a headed cylindrical member. In this operation, the insert 3 is drawn out into the stem portion il formed on the blank and a portion of the insert extends laterally, as at i2, and distributes itself within the head portion I3 formed on the blank.

At the end of the extruding operation, any excess metal of the insert expands through the end of the recess as shown at ill of Figure 4. The excess insert metal is removed to thereby leave a smooth top on the head I3 of the valve.

The valve blank is again heated and forged and machined to the shape shown in Figure 6.

Figure 5 illustrates a valve blankformed in a slightly different manner. In this case, the blank I having the insert 3 is forced through the die block 4 in reversed position in such a manner that the recessed end of the blank is extruded through the cylindrical opening 9. In this modiflcation, the head portion I3 of the blank completely covers the insert 3 as shown at I5, and the excess metal of the insert is forced out through the end of the stem as shown at I6. The excess metal I6 is removed and the recess may be closed in any suitable manner as by welding a metal piece thereacross.

The heating of the metal of the blank I and the subsequent cooling thereof after the formation of the valve tends to shrink the metal about the insert. This shrinking action, together with the forging operation assures a firm bond between the metals.

Many changes may be made in the design and proportion of the parts and the arrangement of the steps carrying out this process, and I do not wish to be limited otherwise than is necessary by the prior art and the scope of the appended claims.

I claim as my invention:

1. The method of making a cooled valve which comprises heating a metal blank having a recess therein to expand the metal and recess, forcing a cold metallic insert of desired characteristics into the expanded recess and working the composite blank thus formed to form a valve with a head and stem thereon with the insert metal spread out into the head and extending down the stem, said insert being rmly bonded to the blank metal.

2. The method of forming a metal cooled valve which comprises boring a recess in a metal blank, heating the recessed blank to forging temperatures to expand the blank and recess, forcing a cold metal plug into the recess to completely fill the same and extruding the composite blank thus formed to form a head and stem thereon with the insert metal spread out into the head, said insert metal being rmly bonded to the metal of the blank.

3. The method of making copper cooled valves which comprises providing a blind bore in a steel blank axially of the blank, said bore extending from one end of the blank into spaced relation from the other end thereof, heating 'the blank to expand the bore, forcing a slug of cold copper into the recess to ll the same and Working the composite blank thus formed while hot to provide a head and stem thereon with the insert metal spread out into the head and the excessive amount of metal extending beyond the mouth of the bore and thereafter removing the excess metal extending beyond the mouth f the bore.

ARCI-IIE T. COLWELL.

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