US1847742A - Connecting rod - Google Patents

Description

March 1, 1932. p. E. ANDERSON CONNECTING ROD Filed Oct. 13, 1930 hI/IIIIlI/A INVENTOR Par/J 74/74 16 ram ATTORNEYS R H Q Patented Mar. 1, 1932 UNITED STATES DAVID E. ANDERSON, or DETROIT, MICHIGAN, AssIGNoR To 'RCHN ALUMINUM ANn BRASS CORPORATION, or DETROIT, MICHIGAN, A CORPORATION or MICHIGAN CONNECTING ROD Application filed October 13, 1930. Serial No. 488,494.

This invention relates to connecting rods designed for use in high speed internal combustion engines and consists in the novel construction as hereinafter set forth.

In the drawings:

Figure 1 is a side elevation partly in section of my improved connecting rod;

Figure 2 is a central longitudinal section therethrough Figure 3 is a bottom plan view of the cap.

In the present state of the art all manufaoturers of high speed internal combustion engines are experiencing a short life from connecting rod bearings. This is primarily due to the fact that bearing loads increase asthe square of the speed with the result that heat frictionally generated frequently rises to the point where the Babbitt lining is melted. To overcome this difliculty connecting rods have been made of aluminum which has a much higher thermal conductivity than steel. These have not, however, proven satisfactory, chiefly through the high coefficient of expansion of the aluminum which renders it difiicult to hold the bearing tight at high temperatures without having it too tight at low temperatures.

The present invention is based on the discovery that the frictional heat of the hearing may be more'rapidly and successfully dissipated through the cap than through the body of the rod. The reason for this is that at high speed operation the bearing in the cap of the rod is more heavily loaded than the bearing in the body. This in turn is due to the fact that at high speed operation the inertia forces are far in excess of the explosion forces as the resultant load from explosion, compression, inertia and centrifugal force falls to a great extent on the cap. This being the case, more heat will be frictionally developed in the cap than in the rod.

My improvement consists essentially in a construction of rod, the body portion of a which is formed of steel, and the cap of aluminum alloy. The steel body being of the same material as the crank pin will have a corresponding rate of expansion and by properly designing this steel body, the expansion of the-aluminum cap may be held Within perpate the same.

consequent higher convection rate through contact with the air.

In detail, A is a connecting rod preferably formed of a steel forging and having the head B forming a half bearing for the crank pin. C is a cap formed of aluminum, magnesium or other light materials having a high rate of thermal conductivity. This cap is designed with projecting segmental fins D for increasing both the extent of radiating surface and also the strength and rigidity of the structure. Both cap and body of the rod are provided with Babbitt linings E E. The cap is secured by bolts F and clamping nuts G.

The construction as above described has been subjected to severe tests of running continuously at a high rate of speed without detrimental results. This is due to the fact as above set forth that the heat is directly and effectively dissipated from the point of generation. Also considerable weight is saved by making the cap of aluminum in place of one of steel.

What I claim as my invention is:

1. A connecting rod comprising a body portion formed of steel and a cap for the crank pin end of the rod formed of a metal having a much higher coefficient of thermal conductivity fashioned to dissipate the heat from the bearing.

2. A connecting rod comprising a body formed of steel and a cap for the crankpin end of the rod formed of a metal of the aluminum group fashioned to dissipate the heat from the bearing.

3. A connecting rod comprising abody including a half bearing for the crank pin the said body and half bearing being formed of steel, and a cap formed of an alloy chiefly of metal of the aluminum group fashioned to dissipate the heat from the bearing.

4. A connecting rod comprising a body infor the crank pin aring being formed steel, a complementary cap formed of an oup and having a Babbitt lining said cap eing fashioned to dissipate the heat fromthe bear- In testimony whereof I affix my signature.

DAVID E. ANDERSON.

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