US2210593A - Bearing alloy - Google Patents

Description

Patented Aug. 6, 1940 Q UNITED STATES 'BEARING ALLOY William E. McCullough, Detroit, Mich., assignor to Bohn Aluminum & Brass Corporation, Detroit, Micln, a corporation of Michigan No Drawing. Application July 31, 1939,

i Serial No. 287,681

2 Claims.

The invention relates to alloys and more particularly to alloys adapted for use as bearings, as for example a lining in a shell of a dlfierent metal. 7

One of the principal objects of the invention is to obtain an alloy which has better properties and characteristics than Babbitt metal. More particularly, it is an object of the invention to obtain an alloy having higher compression 10 strength at elevated temperature, greater resistance to cracking due to fatigue, more effective bonding to the backing metal while at the same time having at least as good resistance to shaft wear as Babbitt.

small amounts of othermetals may sometimes be present either as impurities or intentlonallyf added. p. In its broader aspects, my invention comprises alloys having the following analysis:

Per cent A 0.5 to 1.6 Sh 5.0] to 15.0

Sn Balance However, other metals such as copper, nickel,

iron, zinc, cadmium and lead may be present singly or in combination providing the total of so these metals is not substantially in excess of 1.5%.

As illustrative of my invention, the following specific examples are given:

85 Alloy Silver Antimony Tin Percent Percent Example 1 2.12 7. 57 Balance Example 2. 3. 7.32 Do. Example 3 4. 56 4. 49 Do. Example 4 6. 98 6. 72 D0. 40 Example 5 7. 51 6. 89 Do.

bronze or wrought bronze. In preparingsuch composite bearings, it is desirable to use a flux such as acidified zincchloride on the shells and then to tin the shells. The tinning may be carried outwith pure commercial tin or with an alloy of such tin with up to 15% of lead. Generally speaking, I prefer to use commercially pure tin for the first coating prior to lining with my new alloys.

As before stated, one of the advantages of my new silver 'alloys is that they have higher com- My improved bearing alloys are essentially ternary alloys of tin, silver and antimony, although I pression strength at elevated temperatures than Babbitt 'alloys containing corresponding amounts of copper. This is illustrated by the following tests which compare the compression strength both at room and elevated temperatures. In carrying out the tests, cylinders of four compositions, A, B, C and D as listed below, were cast in graphite molds and machined to one-half inch diameter and one and one-half inches length.

Alloy Copper Silver Antimony Tin Lead Percent Percent Percent I Percent A 2. 12 None 7. 22 Balance 0.'15 B 3. 66 None 6; 79 .do 15 C None 2. 12 7. 57 do 10 D None 3. 40 7. 32 do l5 .it will be observed in the above table that .Babbitt alloys A andB were substantially the same as my new silver alloys C and D except that they had copper instead of the sliver of my alloys. The cylinders were tested under compression and the loads determined at 1% permanent reduction in height of the specimens at F. and

17 permanen 1'7 rmanent 33% time F. 831%; W F.

Lbs. per sq. in. Lbs. per rq. in.

tion D and fully machined by turning, boring and broachingin a well known manner. The lining metal machined very well and after broaching of the lining hada mirror-like surface, free from porosity, gas holes, oxides or any other defects.

To illustrate another advantage of my alloys the bearing lined with composition D was cut into half shells, flattened with a hammer, and after repeated bendings, it was impossible to separate the silver-antimony-tin lining from the steel shell by use of a chisel or any other means except to conventional production practice to fit a wellknown automotive connecting rod. The bearings were tested in a standard and generally used testing machine under conditions of loading, shaft speed, oil temperature and duration to simulate extreme hard conditions of engine o pera tion. Similar bearings lined with composition D were tested under the same conditions.

that Time beam] Shaft Bearing of op- 011 was Oil Bearing speed, load, erasure, temp., temp., R. P. M. P. s. 1. tion, P. s. I. F. F mm hours alloy 2 3200 1382 1 75 221 250 240 3750 1897 1 75 238 276 266 4000 2159 20 75 273 1 D 1800 437 l 75 207 g 2800 1058 1 75 205 $1 1 3200 1382 1 75 210 g 3750 1897 1 75 233 273 278 4000 2159 20 75 242 297 297 The schedule of oil and bearing temperatures show the variations normally experienced in such testing, the early variations occurring during the conformation of the bearing surfaces to the .shafts. At the end of the tests the bearings were ings after approximately 30,000-40,000 miles of 3 engine operation in an automobile, the superiority of my alloys when used as'bearing liningslfor 1 engines is clearly indicated.

The above tests show thattmy new silver-alloys have physical properties of such a character 1 as to make them more desirable for use as linings in bearing shells than the Babbitt metal of the prior art. Thus by means of my invention I have produced an improved composite bearing. a

What I claim as my invention is:

1. A hearing alloy comprising antimony 5 to 15%, silver 0.5 to 7.6% and the balance of tin.

2. A bearing alloy comprising antimony 6.5% to 8.0%, silver 2 to 7.5% and the balance of tin.

W'HLIAM E. MCCULLOUGH.