USRE21495E

USRE21495E - Bearing

Info

Publication number: USRE21495E
Authority: US
Publication date: 1940-06-25

Description

"c. R. SHORT. I

BEARING Original Filed se p. 22; 1927 Imam-0R Reisaued June 25, 1940 assume Charles a. Short, Cler incnt, m, mm, by

mesne assignments, to General Motorso bo ration, Detroit, Mich., a corporation of Delaware Original No. 1,819,272, dated Allllllt rial No. 221,340, September 22, 1927. v

18, m1, seln mtion for reissue December 18, 1039, Serial No.

14 Claims.

This invention relates to machine elements having surfaces adapted to be placed in rubbing contact with a relatively movable part, such as a bearing for a shaft.

It has been heretofore found desirable to employ porous metallic material as a bearing surface in elements of this character, and to secure this porous metallic material to a backing or reinforcing member of denser metal, by means of a metallic bond between. the porous and denser members, said'bond alloying with the porous and denser metals to securely attach said metals together. Under certain conditions as, for instance, when the machine element becomes highly heated, the bond may be wholly or partially broken down due to a tendency of the porous material to absorb the bonding material when hot, thus permitting the porous bearing surface to become loose.

It is the primary object of this invention to provide a novel and improved machine element of this character in whichzthe porous metallic bearing surface is securely attached to the reinforcing member in such a way that it will remain so attached during all conditions of manufacture and operation. a It is also a further object of this invention to devise a novel method of making machine elements of the type described in which the bearing surface is attached to the reinforcing mem; ber in an improved manner. I

With these objectsin view, one feature of the 1 invention consists in the provision of a machine element having a porous metallic bearing sur-' face, secured directly to a denser metal reinforcing member, without the use of any intermediate bonding material. I

A further featureoi the invention consists in a method of making such a machine element in which the step of attaching the porous bearing surface to the denser metal back consists in heating the two. metal elements to a high tempera- 'ture while clamped together under pressure. The

invention also contemplates the heating of the elements clamped together as described in a liquid bath.

The invention further contemplates the heating of the elements while clampedv together as described; by means of an electric circuit to electrically weld such elements together.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the. present invention is clearly shown. I

In the drawing:

Fig. 1 is a plan viewof a preferred porous metallic plate.

Fig. 2 is an enlarged sectional 2-2 of Fig. 1.

Fig. 3 is-a sectional view, largely diagrammatic, of apparatus used to weld the porous metallic plate to a reinforcing member, for example a form of view on the line connecting rod.

Fig. 4 is an enlarged fragmentary section of a connecting rod bearing formed according to this invention.

In my copending applications, Serial Nos. 188,- 930, now matured into Patent No. 1,768,529, and 221,341, now matured into Patent No. 1,834,746, and filed respectively May 5, i927, and September 22, 1927, I have disclosed bearings having a facing consisting of a thin sheet of porous metallic material, secured to a reinforcing backing of denser metal having a greater tensile, strength, and certain methods of making such bearings. The porous metallic element employed in such bearings has been either such an element as described in the application of H. M. Williams, Serial No. 582,550, filed August 17, 1922, and now matured into Patent No. 1,842,347, or such an element as described in my copending application, Serial No. 221,341, filed September 22, 1927, Patent No. 1,834,746 above referred to. The porous metallic element described in the Williams application is of substantially the same porosity throughout, while that disclosed in my copending application is of laminated construction having layers which differ in degree of porosity. The methods employed to make these metallic elements'form no part of this invention and need not be described in detail herein. Briefly, itmay be said that the porous metailic element disclosed in the Williams 1,642,347 is made by briquetting together a mixture of metal powders, together with graphite and a volatile void forming substance such as salicylic acid. The briquette is then sintered in a non-oxidizing atmosphere for a sufllcient period to complete Another material which incorporates lead therein may have a formula as follows:

Parts copper Tin 13841 35 Graphite .6 Salicylic acid 4 The metal element disclosed'in my copending application is made by adding a layer, principally copper or copper alloy to the porous metallic element disclom in the Williams application.

Inl'ig. l of the drawing,.is disclosed ametallic element 2. which is of novel and improved forni to give the best results when bonded directly to the reinforcing member without use, of an intermediate metal bond suchras tin, which has been formerly employed in making bear-3 ings with a porous metallic facing. It has been found that when the porous metallic facing is secured directly to the denser metal backing, particularly by electrically welding as set forth hereinafter, better results are obtained if a portion only of the two contacting surfaces are bonded. The metal element II according'to the present invention is formed with an embossed surface, having areas 2i projecting above the remaining surface of said metallic element. The element is embossed in anysuitabie manner, for example; by pressing with a dierof proper shape to secure the desired formation. It will be understood also that the raised areas Il may be formed from the body of the metallic element as the element itself is formed, or may be formed thereon at .a subsequent operation. The projecting areas II are joined to a reinforcing member of denser metal in the manufacture of a hearing as later described.

The metallic element described may be of sub-,

stantiaily the same degree of porosity throughout or may be an element having the laminated construction described in my copending application previously. referred to. Itis more desirable to use the laminated form of metallic element and form the ojecting areas II on the less. porous metallic layer, for thereason that the less porous layer has greater tensile strength than the more porous metallic layer, and when attached to the denser metal reinforcing member, a stronger bond is formed which will require a greater force to break it down, than u themore porous material were secured to the reinforcing member. As

set forth previously and more fully" explained later, a more desirable bond is secured when a metal element having an embossed surfam is secured directly to its reinforcing back by weldthedesired'alloying. Oneofthepowderodmetal tureoflm'toliitiilland'arethenquickly mixtures includes: cooled. This temperature will depend on the copper 90 Theciammd assembly may be heated in any Tin i desirable manner, and satisfactory results Graphite- 6 been obtained when said assembly is heated in'a Salicylic acid 2 to 4 bath of molten salts.

, The porous material may be composed of copper and an alloy of copper and other substances. When the porous material is heated while held in contact with the denser metal backing to the temperature referred to. a part of this alloy of copper arid other substances melts, but the specifiedtemperature is less than the melting point of copper. On cooling the melted portion of the alloy forms a bond attaching the porous metal to its reinforcing body. H

It is also within the scope of this invention to effect the joinder of a porous metallic element to a denser metal member by heating to high temperatures by means of an electric current to electrically weld the two elements together. In accordance with this method of bonding" the two" elements, the porous element is held against the member to which it is to be attachedrwith the projecting areas it in contact therewith. One conductor of an electric circuit is in electrical connection with the reinforcing member, while the other conductor of said circuit is in connection with an electrode which is brought into engagement with the exposed surface of the porous element.

m Fig. 8 is disclosed dl -srammaticaliy a suitable apparatus for effecting .ioinder of the two metallic elements by electric welding. The apparatus disclosed is designed to weld a porous metallic element of curved form to the curved surface of a connecting rod bearing. As disclosed I a connecting rod 22 is supported on a supporting cradle 2: having a hole therein through which.

the rod extends. The cradlev is pivoted at '24 so as to have a rocking movement. The porous element II is placed in the curved endpf the rod 22, with the projecting surfaces ii in contact with the surface of the connecting rod. An electrode 2! having a roller adapted to engage the upper surface of the metallic element II is supported above such element and is adapted to be brought into engagement therewith by any suitable means so as to press the element II into. engagement with the connecting rod with a moderate pressure. A conductor 2! constituting one branch of an electric circuit connects the electrode with a suitable source of electrical energy, while a conductor a connects the cradle II with such source of energy. a switch I! being provided to make and break the circuit as desired.

when the electrode is in such position as to hold the element ll against the adjacent surface ofthe connecting rod the switch is closed and the cradle is rocked to bring the roller It above the projections 2i successively. As the roller successively comes above the areas If, a positive contact is established at such areas and they are welded to the rod 23. By using a metallic element having raised surfaces a higher temperature is possible at the contacting surfaces with a given current and. a better weld is secured than if it be attempted to weld one plane element to another throughout their entire contacting areas.

While apparatus is shown for carrying out this method in the making of curved bearings only.

it is obvious that said method can be employed in the manufacture of flat bearings. In making such bearingafinstead of using a pivoted cradle such 'aszs..-;- a;;,. "e having lateral movement with respect .;to the3 electrode 2| could be employfl zf In'li'ig, 4.is disclosed a connecting rod assembly having a facing of porous material bonded to' the steel rod. An element is shown between the rod 22 and the cooperating crank shaft II.

In Fig. 4. which is on an enlarged scale, it

will be seen that between the projections 21 are channels 3i which are formed when said proiections are formed on the element 20. These proment ll hada plane surface thereof secured to the reinforcing member, so that any oil reaching the bearing would have to be absorbed by 'said:

element-2| through the ends thereof.

While the-form of embodiment of the .present invention as herein disclosed. constitutes a preferred form, it; is to be understood that other forms might b'e" adopted, all coming within the scope of theclaims which follow.

Whatis-claimed is as follows:

1. In the methodof making bearings for shafts and the like, the step of welding, a preformed porous metallic lining to a reinforcing member of denser metal which consists in holding said elements in direct contact and heating the said elem'entsto a high temperature while so held.

2. In the method of making bearings for shafts and the like, the step of attaching a preformed porous metallic facing consisting of a plurality of metals having-different melting points to a reinforcing member of denser metal which consists in holding the two metallic elements in direct contact and heating said elements while soheld to a temperature intermediate the melt-' ing points of the different metals in said metallic facing,,wh ereby"said porous facing is welded directly tosaid reinforcing member.

3. The method of attaching a preformed bearing element having a porous metallic structure consisting of almixture of metals tea reinforcing element of denser metal which consists in holding the said two elements in direct contact and heating said elements while so held to a degree sufficient to melt only the lower. melting constituents of said metallic structure.

' 4. The method of attaching a preformed bearing element having a porous metailic structure of' bronze to a reinforcing member of ferrous metal which consists in holding said bronze and ferrous elements in direct contact and heating such elements while so held. to a temperature intermediate the melting points of the high and low melting point. constituents. of said porous bronze structure;

5.;In-the method of making bearings for shafts and'the'like, the steps of attaching a preformed porousmetailicbearing lining to a denser metal reinforcing member which consists in holding the distributed raised 'areas on the back surface of the porous lining, pressing said back surface in direct contact with said denser metal'and heat- :two metal elements ing the contacting areas of the two metal elements to weld said lining and reinforcing member together. I

7. In the method of forming bearings for shafts and the like. the step of attaching a porous metallic lining to a denser metal reinforcing member which consists in forming substantially uniformly distributed raised areas on the back surfaceof the porous metal lining, pressing said back surface directly upon said reinforcing member and electrically welding the contacting areas of the progressively until all such areas are welded. g 8. The process of making a composite machine I element which includes the steps of providing a backing member of ferrous metal, providing a porous facing composed of compressed powdered material consisting at least predominantly of high-melting-point metal and which is substantially free from iron-corroding gases and vapors sorbed therein, said porous facing being formed by sintering the compressed powdered material in a controlled atmosphere; holding the facing with the surface thereof in firm contact with the surface of the backing member of the ferrous metal and heating the facing and the backing member while so held to effect a direct weld between the ferrous metal of the backing member and the hig'h-melting-point metal of the facing without fusion of the latter metal.

9. A process as claimed in claim 8 in which the provision of the porous facing substantially free from iron-corroding gases and vapors sorbed therein includes heating the porous facing of compressed powdered material sufilciently to drive out of the facing substantially all ironcorroding gases and vapors sorbed therein before the facing is contacted with the backing member in the welding operation.

10. A process as claimed in claim 8 in which the porous facing member is provided by compressing powdered material composed predominantly of high-melting-point metal and containing also lead, tin and graphite.

11. A composite machine element comprising in combination a ferrous metal backing member and a facing thereon consisting of a porous body of condensed and coherent powdered material composed at least predominantly of high-melting -point metal, the backing member and the facing being united substantially throughout their mutually contacting surfaces by a direct weld substantially stronger than the facing body,

said facing being formed by sintering condensedpowdered material in a controlled atmosphere so that the facing is substantially free from ironcorroding gases and vapors sorbed therein, and

said backing member and said facing being united by holding the facing with a surface thereof in firm contact with a surface of the backing member, and heating the facing and backing member while so held toeflect. said direct weld between the ferrous metal of the backing member and the high-melting-point metal of the facing without fusing the latter metal.

12. A composite machine element comprising in combination a ferrous metal backing member and a facing thereon consisting of a porous body of condensed and coherent powdered material composed at'least predominantly of high-melting-point metal, the backing member and the facing being united, substantially throughout their mutually contacting surfaces by a direct weld substantially stronger in shear parallel to the welded surfaces than the faci'ng body, said 4 facing being formed by sintering condensed powdered material in a controlled atmosphere so that the facing is substantially free from ironcorroding gases and vapors sorbed therein, and

.said backing member and said facing being united by holding the facing with a surface thereof in firm contact with a surface of the backing member, and heating the facing and backing member while so held to effect said direct weld between the ferrous metal of the backing member and the high-melting-point metal of the facing without fusing the latter metal.

13. A composite machine element comprising in combination a ferrous metal backing member and a facing thereon consisting of a porous body of condensed and coherent powdered material composedat least predominantly of high-melting-point metal, the backing member and the facing being united substantially throughout their mutually contacting surfaces by a direct aims the facing and backing'member while so held "to eflect said direct weld between the ferrous metal of the backing member and the high-meltingpoint metal of the facing without fusing the latter v metal.

14. A composite machine element comprising in combination a ferrous metal backing member and a facing thereon consisting of a porous body of condensed and coherent powdered material composed at least predominantly of high-melting-point metal, the member and the facing being united substantially through their mutually contacting. surfaces by a direct weld characterized by a substantially distinct line of demarcation between the backing member and the facing and by substantially greater strength in shear parallel to the welded surfaces than the facing body, said facing being formed by sinterlng condensed powdered material in, a controlled atmosphere so that the facing is substantially free from iron-eorrodlng gases and vapors sorbed therein, and said backing member-and said facing being united by holding the facing with a sur-, face thereof in firm contact with a surface of the backing member, and heating the facing and backing member while so held to efl'ect said direct weld between the ferrous metal of the backing member and the high-melting-point metal of the facing without fusing the latter metal.

CHARLES R. snon'r.