US2089749A - Valve - Google Patents

Description

Aug. 10, 15537. R JARDINE 2,089,749

VALVE Filed Nov. 2, 1933 INVENTOR Wya/IM M M ATTORN EY Patented Aug. 10, 1937 UNITED STATES PATENT OFFICE VALVE Application November 2, 1933, Serial No. 696,404

3 Claims.

This invention relates to valves, more particularly to hollow valves of the poppet type such as are used in internal combustion engines.

One object of the invention resides in the provision of a hollow valve having a quantity of cooling medium, capable of being quickly and cheaply produced and adapted to effectively contain the cooling medium against leakage.

Another object of the invention resides in the provision of a valve having an enlarged opening in the valve head for holding cooling medium, the valve having a cap or top which iswelded to the valve body portion and which is also so fitted in the valve body Portion as to be joined or locked at the body portion independently of the weld.

Another object of the invention resides in the method of making a valve in which a separate cap or top is welded to a valve body or shell and in which a shrink fit is provided between conical surfaces provided on the body and on the top.

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, central section through a valve embodying the present invention;

Fig. 2 is an enlarged fragmentary section corresponding to Fig. 1-;

Fig. 3 is a central section of a modified form of construction;

Fig. 4 is a, central section of another modified form of construction; and

Fig. 5 is a central section of still another modiiication of the invention.

Referring more particularly to the drawing and more specifically to Figs. 1 and 2, l0 designates generally a hollow valve containing a quantity of cooling medium il partly filling the hollow chamber l2 provided in the valve stem and also in the valve head. It will be noted that the chamber I2 is of considerably larger diameter in the valve head so that the cooling medium efiectively cools the outer portion of the valve head and effectively transmits the heat from the head of the valve to the stem portions from which the heat may be dissipated.

The valve In comprises a main body portion 14 which is of suitable steel. Integrally connected to the body portion I4 is a separate cap or top portion l5 also of suitable steel. The body portion I4 is made by suitable machining operations to form the lower portion of the valve head as indicated at l6 and the stem portion ll. If desired the body portion l4 may be formed from a bar which is drilled through, the head portion l6 being formed by enlarging the diameter at that end of the bar, while the other end of the bar is closed or substantially closed by a swaging operation. The substantially closed stem portion of the bar is then drilled and tapered to receive a pin l8, the opening in which the pin is received being provided for filling the hollow chamber with the cooling medium. The body portion l4 may, if desired, be made by machining the entire body portion from a piece of metal substantially of the same diameter as the largest finished diameter of the valve.

In making the body portion l4, a seat surface 20 is provided by a suitable turning or grinding operation. As shown in Figs. 1 and 2, the seat surface 20 is slightly tapered or conically formed, the conical surface 20 being of slightly larger diameter adjacent the valve stem than adjacent the head end of the valve. This surface 20 is of substantial length and is adapted to receive a corresponding tapered surface 2| machined on the cap or top IS. The 'angle of the taper may be approximately two and one-half degrees in a valve of about a three inch head diameter. The diameter of the' surface 2| on the valve top l5 maybe made about .001" larger than the corresponding point of contact with the surface 20 of the valve body portion. The two parts of the valve are 'then joined and locked together by heating the valve body portion to a temperature of about eight hundred degrees and by shrinking the valve cap I5 as by cooling the same in liquid air. The two parts may then be readily assembled so that the end 22 of the valve cap seats against the annular surface 23 of the valve body, both of these surfaces being accurately machined. After placing the valve cap in the valve body as described above, the two parts will reach the same temperature and the cap will then be locked or connected to the valve body.

After shrinking the valve body on the cap, the two parts are connected and sealed by a fused interconnection. This interconnection in accordance with the construction shown in Figs. 1 and 2, embodies a weld of cobalt alloy such as stellite, the weld extending annularly around the valve head and integrally interconnecting adjacent portions of the valve cap and valve body and thus permanently and securely sealing any tiny cracks that might be present between the joining surfaces of the cap and body. The stellite may also extend around the outer portions of the head so as to form a hard seat surface '24, if desired. After sealing and connecting the valve head to the valve body, the cooling medium 55 II is added through the tapered hole provided in the valve stem. This cooling medium may be sodium, or may be other similar metals or mixtures of salts that are a liquid at the normal operating temperature of the valve which eflectively transmits the heat by a turbulent action from the valve head to the valve stem. After adding the cooling medium H, a plug I8 is driven in the tapered filling hole and a weld 26 01' suitable material is also applied over the stem end of the valve to hold the plug in place and to very definitely seal any tiny cracks that might be present so that the cooling medium cannot find its way out of the chamber in the valve.

After sealing the cooling medium in the valve, the entire valve may be heat-treated at a temperature of about five hundred degrees for an hour-or so to equalize stresses in the connections, and to see if any leakage occurs past the welds. After this operation the finished surfaces of the valve may be machined and finished to the exact size required.

In accordance with the construction shown in Fig. 3, a valve body 26 may be suitably machined in a manner previously described, in this case the stem end of the valve being entirely closed by swaging or similar operation. The machined seat surface 21 provided on the valve body may be either cylindrical or conical, and if conical should not be of greater diameter at the head end of the valve than at the stem end. The valve cap or top 28 is applied in the same way as in the construction shown in Fig. 1 that is by shrinking the valve body around the cap so as to securely lock the two parts together, the valve cap where it fits in the seat provided in the body being about .001" larger in diameter than the surface H with which it contacts. Inasmuch as this difierence in diameter is comparatively small, no substantial strains will be imposed on the metal of the valve head, but the two parts will be held securely together. The adjacent surfaces of the valve head and cap may then be permanently and integrally sealed together by a stellite weld 28a. The cooling medium 29 is applied through the small filling hole 30 provided in the valve cap 28. This hole 30 is preferably threaded and after the cooling medium is added a plug 3| is screwed in so as to fit tightly in the filling opening. The outer end of the opening which preferably flares outwardlyas shown is then filled with a stellite weld or the like so as to seal any small cracks and hold the-plug 3| in place against any movement.

In accordance with the construction shown in Fig. 4, the valve cap 34 fits tightly in the valve portion 35, the connection being a threaded one as indicated at 36. In this modification the body portion 35 is not shrunk around the cap 34 but the threaded connection 36 is accurately made so as to provide a tight fit or lock between the two parts independently of the weld. The weld of stellite or the like as indicated at 31, is applied. annularly around the valve head, the valve body portion and top portion being grooved as shown adjacent the point of connection so as to leave a recess in which the weld material 31 is received. In this form of construction the cooling material such as sodium or the like is applied through a filling hole having a plug 38 in the valve cap 34, the end of the filling hole being sealed by a weld of stellite or the like, as indicated at 39.

As shown in Fig. 5, the valve body portion 40 is connected to the valve cap portion 4| by a tapered or conical joint 42, the conical seat sur face provided on the valve cap being of slightly larger diameter toward the stem end of the valve than toward the head end, and the seat surface provided in the body portion 40 being correspondinglytapered and of slightly smaller diameter in accordance with the construction shown in Fig. 1. The filling material is applied through a filling opening 43 provided in the cap ll, and the filling plug 44 which is subsequently applied in the hole 43 is sealed in place by an acetylene weld 45. In this construction the lock provided between the cap II and the valve body 40 is reinforced, and the cooling medium definitely and permanently sealed. in the valve against leakage by means of hydrogen copper brazing, the copper 46 extending annularly around the valve head and covering the joint between the cap and the body portion.

It will be apparent that the machining of the body portion of the valve may be economically carried out. The valve cap may also be readily made, the two portions of the valve being so machined as to have accurately made seat portions of substantial length by means of which they are securely locked together against relative movement. The weld or fused interconnection between the body portion and cap covers the joint and eflectively seals the cooling medium against leakage and reinforces the joints provided by the shrunk connection between the valve body and the cap or top. The arrangement is therefore such as to efiectively hold the cooling medium against leakage and to provide a valve which is adapted to withstand the high temperatures to which it is subjected in use.

While themethods herein described, and the forms of apparatus for carrying these methods into efiect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise methods and forms of apparatus, and that changes may be madein either without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A liquid cooled poppet valve for internal combustion engines having a hermetically closed chamber in the head and stem with the chamber. of larger diameter in the head of the valve comprising'a steel body portion forming the stem and lower part of the head, a separate top portion, and an annular weld of cobalt alloy integrally interconnecting and sealing said portions, the cobalt alloy weld also covering the peripheral parts of the valve head to provide a thin hard layer over the seat portions of the valve, and a quantity of cooling medium partly filling the closed chamber.

2. A liquid cooled poppet valve for internal combustion engines having a hermetically closed chamber in the head and stem of larger diameter in the head than in the stem, comprising an integral steel body portion forming the stem and lower part of the head, a Separate top portion, and an annular weld joining and sealing said portions, said top portion having a peripheral conical surface of larger diameter towards the valve stem closely fitting throughout a substantial length of contact within a conical surface of the body portion which is also of larger diameter toward the valve stem and having a shrunk fit therein so that the top portion is locked to the body portion independently of said annular weld and a quantity of cooling medium partly filling the closed chamber.

surface in the body portion and thereby securely held to the body portion independently of said annular weld, a small filling opening provided in said top portion, a plug welded in said opening and hermetically sealed therein, and a quantity of cooling medium partly filling the closed chamber.

ROBERT JARDINE.

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