US1903485A - Internal combustion engine - Google Patents

Description

April 11, 1933. G. W SMWH, JR 1,903,485

INTERNAL COMBUSTION ENGINE Filed NOV. l0, 1930 IA' l/'ENTOR A TTORNE Y GW. 5MlTH,Jr.

Patented Api.' 11, 1933 UNITED STATES PATENT OFFICE GEORGE W. SMITH, JB., OF CLEVELAND, OHIO,ASSIGNOR TO THE WHITE MOTORCOM- PANY, 0F CLEVELAND, OHIO, A. CORPORATION OF OHIO INTERNAL COMBUSTION ENGINE Application led November 10, 1930. Serial No. 494,556.

This invention relates to internal combustion engines of the poppet valve type, and more particularly to valve seats for such engines.

It is an object of my invention to provide a new construction for a valve seat unit for an internal combustion engine which can be employed to overcome many of the difficulties encountered in securing valve seat materials in engine parts constructed of dierent materials.

As hereinafter disclosed, a unit constructed in accordance with my invention can be successfully employed to eli'ect the securement in an engine part of a body of valve seat material having a materially dilerent coeiiicient of thermal expansion than the engine part.

My invention further possesses utility in instances in which it is desired to use a costly valve seat material, the units employed in such instances being constructed with small valve seat portions, and with base portions of suitable design to properly support the valve seatparts.

My invention also possesses utility in instances in which it is necessary or desirable to secure the valve seat material to the part which supports it by a brazing or similar bonding process, since it permits the bonding process to be performed in a facile manner with small parts.

Other uses of my invention will occur to those skilled in the art to which my invention pertains.

In the drawing:

Figure 1 is a fragmentary side elevation, partly in section, of an engine equipped with valve seat units constructed in accordance with this invention.

Figure 2 is a fragmentary bottom plan view of the cylinder head of the engine shown in Figure 1.

Figure 3 is a perspective view, drawn to a relatively large scale, of an unfinished part of a valve seatrunit of the type illustrated in Figures 1 and 2.

Figure 4 is a perspective View, drawn to the same scale as Figure 3, of a second unfinished part of a valve seat unit of the type illustrated in Figures 1 and 2, and

into the cast-iron .cylinder head. 11 adjacent the interior end'of each exhaust vpassage 13, there is a valve seat insert or? unit 16 consisting of a threaded outer. steel' part 17 and an inner aluminum-bronze valve'se'at part 18 affixed to the steel part 17 in 'such a manner as not to become detached therefrom by unequal expansion or contractionof the metals of thel two parts.

The aluminum-bronze alloy valve'seat parts 18 are constructed is particularly adapted for use in valve seats, but .due to its relatively high coetlicient of thermal of which the expansion has been found in practice to be exceedingly dilicult to secure in place in a castiron part in the form of an insert. In the present construction the diliiculty of securing the aluminum-bronze valve seat parts within the cast-iron cylinder head is overcome by the addition to the valve seat units of the external steel parts 17 which have a coeiiicient of thermal expansion similar to that of cast iron, and which for that reason maintain a tight threaded engagement with their seats 19 in the cylinder head throughout the range of temperatures to which the inserts and the adjacent port-ionsof the cast-iron cylinder head are subjected.

In the initial construction of an insert 16, an aluminum-bronze 18a of the form shown in Figure 3 is securely bonded within an unthreaded steel part 17a as shown in Figure 4. This may be accomplished by brazing or soldering nthe aluminum-bronze part to the steel part, the steel part in su'ch case being constructed withan inner diameter a few hundredths of an inch larger than the outer diameter of the aluminum-bronze part so as to provide a space for the reception of the bonding material.

Under one process, the aluminum-bronze part 18a and the steel part 17 a are first coat- -ed with a spelter of brass by dipping them in a molten bath of that metal upon which is floated a flux of borax. The aluminumbronze part is then placed in an assembled position Within the steel part, and the two parts immersed in the molten spelter bath for a period of several minutes, after which the two parts are withdrawn and allowed to cool.

Under a second process, the parts 17a and 18a are placed within the flame of a gas torch and heated to a temperature of about 1450 degrees Fahrenheit, the iame being adjusted at the termination of the heating period so as to maintain the parts at such temperature. The inner surfacesof the steel part, and the outer peripheral and bottom surfaces of the aluminum-bronze part are then coated with a flux of fused borax which is spread'over the surfaces of the parts in any suitable manner after being reduced to a molten state by the heat of the flame; following which, the steel part is coated with a silver solder consisting of approximately 45 per-cent silver, 25 per cent zinc and 30 per cent copper, the solder like the ux being applied in a molten state after being melted by the flame. The aluminum-bronze part is then placed Within the steel part and the annular space between the two parts filled with molten silver solder of the same character as .that previously described, the solder as before being reduced to a molten state by the heat of the ame. Upon completion of the process, the flame is .extinguished and the parts allowed to cool.

A better bond is obtained in the last described process if the inner surfaces of the steel member 17 a are protected from the flame during the initial part of the process by means of a steel member 20 of the form illustrated in Figure 5. In using the protector member 20, the flux and silver solder used in coating the inner surfaces of the steel part 17a' are applied through apertures 21 in the upper flange of the protector member, and continuously spread over the inner surfaces of the part by rotation of the protector member, and by means of a special tool inserted through the central opening in the protector member. After the steel part has been coated with solder, the protector member is removed, the

aluminum-bronze part inserted, and the an-y nular space between the two parts filled with solder as before described.

Following the bonding of the aluminumbronze, part 18a within the steel part 17a, the excess bonding material adhering to the external surfaces of the insert is removed, and the outer peripheral surface of the part 17a formed with threads. The insert is then screwed into a threaded seat 19 in the cylinder block by means of a special tool which engages the radial projections 22 of the part 18a. After the insert has been set up tightly in the cylinder head, the radial projections 22 are partially removed, and the seating surface 23 added. Should an insertbecome unserviceable, it may be removed by the special tool above mentioned, and a new insert installed. f

Although the inserts 16 have been described as being screwed into the cylinder block, they may be secured in place in some other manner, such as by brazing or shrinking them within suitable seats in the cylinder head. Thevalve seat parts 18 may also be secured within the steel parts 17-by various other processes than those described, as for instance by Welding, or by a process similar to that disclosed in United States Patent Number 976,456.

The inlet valves 14 are provided with seats 24 formed Iin the cast-iron cylinder head 11, but if desired may be provided with valve seat inserts similar to the inserts 16. Such construction is, however, not warranted in the present engine as the inlet valves and their seats are not subjected to sufliciently high temperatures as to materially lessen their resistance to wear, or to cause a material amount of scaling or pitting of such parts.

Although the foregoing description has been concerned with securing a valve seat in an engine part constructed of a material having a diHerent coefficient of expansion, it will be understood that my invention is not limited to such use, but may be employed, irrespective of the purpose for which it is empl-oyed, to secure a valve seat of any desirable metal in an engine part constructed of any metal adapted for suchv use.

j It willbe understood that various changes and ymodifications in construction may be resorted to Without departing from the spirit and scope of my invention.

I claim as my invention:

1. A valve seat unit for an internal combustion engine comprising an inner portion of metal having a coeiiicient of thermal expansion materially different than the metal of the part to which the unit is to be attached, and an external porti-on of metal having a coefficient of thermal expansion similar to the coeiiicient of expansion of the metal of the aforesaid part.

bustion engine comprising 'an inner portion of metal having a coefiicient of thermal expansion materially different than that ,of cast iron, and an external portion of nieta'l'having a coefficient of thermal expansion similar to that of cast iron.

3. A valve seat unit for an internal combustion engine comprising an outer part of 2. A valve seat unit for an internal comsteel, and an inner part of aluminum-bronze alloy securely bonded to said outer part.

4. A valve seat unit for an internal coml bustion engine comprising a portion constructed of metal having a coeicient of thermal expansion similar to the coeilicient of expansion of the metal of the engine part to which the unit is to be attached, and designed for securement to the aforesaid engine part, and a portion constructed of metal having a different coeilicient of thermal expansion than the aforesaid engine part, securely bonded to said first named parte, and formed with a valve seat surface.

5. A valve seat unit for` an internal combustion en ine comprising an outer art constructed 0% a metal havmg a coe cient of thermal expansion similar to the coefficient of thermal ex ansion of the metal of the engine part to whlch the unit is to be attached, and an inner portion of a metal having a coefficient of thermal expansion different than the metal of the aforesaid engine part, .secured to said outer part by a fused metallic bond, and formed with a valve seat surface.

6. A valve seat unit for attachment to a cast-iron part of an internal combustion engine comprising an outer steel part, and an inner part constructed of a metal having a materially different coeilicient of ex anslon than the metal of the aforesaid castiron engine part, secured to said steel part by a fused meta lic bond, and formed with a valve seat surface.

7. A valve seat unit for attachment to a outer ortion or said engine part, securely bond to said outer portion by a fused metallic bond, and formed with a valve seat surface.

11. A valve seat insert for use in an internal combustion engine in conjunction with a poppet valve for controlling a breathing passage of an engine, designed for securement `within an englne in a recess formed at the inner end of a breathing assage in circumambient relation to the reathing passage, said insert comprising a metallic ortion in the form Aof a ring by which sai insert is 4 secured in place, and a' second metallic ortion constructed of a different metal t an said first named portion, securely bonded to said first named portion by a fused metallic bond, and formed with a valve seat surface.

. In testimony whereof I hereunto aix my signature this 6th day of November, 1930.

' GEORGE W. SMITH, Jn.-

cast-iron part of an internal combustion enginev comprising a threaded steel part de'- si ed for threaded engagement with the a oresaid cast-iron engine part, and a part Y securely bonded to said steel part, constructed of a metal having a' materially different co-- eicient of expansionl than the metal of the aforesaid cast-iron engine part, and formed Y ferent metal thansaid first named portion,

securely bonded to said firstnamed portion, and formed with a' valve seat surface.

9. A valve seat unit for an internal combustion engine comprising an-outer metallic portion, and an inner metallic portion cony structed of a different metal than said `rst named portion, secured to said first named portion a fused metallic bond, and formed with a va ve seat surface. A y

10. A valve seat insert for attachment to a cast-iron part of an ,internal combustion engine comprising an outer steel portion constructed in the form of a ring and designed for engagement with said cast-iron engine,

part, an an inner annular portion, constructed of a different metal than either said

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