US3192607A

US3192607A - Method and apparatus for making a self-aligning pillow block

Info

Publication number: US3192607A
Application number: US187872A
Authority: US
Inventors: Hilton Carl
Original assignee: MASTEN CORP
Current assignee: Return On Investment Corp; Eagle Picher Industries Inc
Priority date: 1962-04-16
Filing date: 1962-04-16
Publication date: 1965-07-06
Anticipated expiration: 1982-07-06

Description

July 6, 1965 c. HILTON METHOD AND APPARATUS FOR MAKING A SELF-ALIGNING PILLOW BLOCK Filed April 16, 1962 INVENTOR. CARL HILTON United States Patent 3,192,667 METHED AND APPARA'EEJS FUR MAKiNG A SELF- ALEGNWG PTLLGW BLOCK Carl Hilton, Chicago, iii, assignor, by means assignments,

to Masten Corporation, (Zhicago, ill, a corporation of illinois Filed Apr. 16, 1962, ar. No. 187,372 9 Gms. (Ci. 29l49.5)

This invention relates to the production of a novel pillow block.

More particularly the present invention relates to a new niethod and apparatus for making a self-aligning pillow b ock.

it is a particular object of the present invention to provide a novel method and apparatus for making a one-piece pillow block wherein the bearing is non-rotatably but pivotally retained therein whereby self-aligning bearings are provided for journaling the ends of a rotatable shaft.

It is a further object of the present invention to provide a method and means for casting a one-piece metal housing about a pre-formed bearing composed of elastic material and whereby after casting the bearing readily separates from the housing to the extent that it can be pivoted within but not disengaged from the housing.

In general, the unit of the present invention comprises an inner bearing member of elastic material such as sintered powdered metal having a spherical outer diameter and a cylindrical inner diameter or bore. The spherical outside diameter of the bearing is substantially enclosed by a rigid one-piece metal housing cast thereabout. The spherical outer diameter of the bearing permits it to pivot within the rigid housing to allow for alignment of a shaft journaled in the bearing.

Large scale commercial production of a unit of the foregoing type has been restricted at the present time, the basic problem therein being casting of a movable spherical insert into a rigid housing and to compensate for the contraction of the housing on cooling. Without some means of compensating for this contraction, the insert is locked in place and as a result cannot be pivoted. One method for compensating for this contraction is to coat the insert with some material, such as a lubricant, which will be dissipated either in the casting process or afterward. The prime reason for making the latter impractical for consistent large scale commercial production is that of main taining a uniform coating on the insert and controlling the dissipation of the coating. Another disadvantage of the aforesaid method is that when suificient coating is obtained for subsequent pivoting of the insert, some means must be introduced to keep the insert from spinning on its axis.

The difficulties of the prior practices are overcome by the present invention which employs a pre-formed bearing composed of elastic material such as the aforesaid porous sintered powdered metal composition. Such porous sintered powdered metal material is elastic within limits and has properties of expansion and contraction and a high degree of elasticity, and these properties are taken advantage of in the present invention.

Other objects and advantages of the present invention together with its details of construction, arrangement of parts and economies thereof will be apparent from a consideration of the following specification and accompanying drawings, wherein:

FIG. 1 is a perspective view of a unitary pillow block formed in accordance with the present invention, and wherein a bearing of the character aforesaid is pivotally disposed and retained within a one-piece metal housing cast thereabout, the housing being of the two-bolt flange mounting type.

FIG. 2 is a section through a one-piece metal housing "ice cast around and in firm embracing engagement with a sintered powdered metal bearing.

FIG. 3 is a sectional view of a die component for compressing the unitary assembly of FIG. 2.

FIG. 4 is a section through the die of FIG. 3 showing the unit of FIG. 2 compressed therein by means of a ram.

FIG. 5 is a section on the line 55 of FIG. 4.

FIG. 6 is a view showing the movement of a shouldered ram into the cavity of the die and contained pillow block assembly of FIG. 4.

FIG. 7 is a section on the line 77 of FIG. 6.

FIG. 8 is a section similar to that of FIG. 7 but with the pillow block removed from the ram and die components of FIG. 6.

Referring to the drawings, the reference numeral 10 generally indicates a one-piece metal housing, for example, aluminum, cast about the bearing generally indicated at 11. The housing is formed with a pair of

flanges

12, 12 each having a hole 13 for reception of a mounting bolt. It will, of course, be understood that the illustrated pillow block unit is for the purpose of illustration and not limitation. Thus, for example, the housing may have a threebolt flange mounting, and in lieu of the axis of the bearing 11 being parallel to the axes of the bolt holes 13, f3, it will be understood that the unit may be in the form of the standard mounting wherein the axes of the

bolt holes

13, 13 are perpendicular to the axis of the bearing 11. Of course, the flanges l2, 12 will then be at an angle of 90 to that shown in the illustration of FIG. 1. Alternatively the housing may be formed without attachment flanges so that the outer surface of the portion which embraces bearing 11 is cylindrical and is later pressed into a cylindrical holder by the user.

The bearing 11, as employed in the present invention, is pre-formed of conventional powdered metals, typical compositions of which are 90% copper and 10% tin; 77.5% copper, 7.5% tin and 15% lead; 25% copper and iron; 20% copper, 79.5% iron, and 0.5% carbon, and the like. A further alternative can be straight iron. These compositions are given for the purpose of illustration and not limitation. The bearings are composed of compressed powders which are sintered in conventional manner to result in compositions having a resilient sponge-like character. These are conventionally employed for selflubricating bearings in that they are porous and can contain approximately 25% of lubricating oil by volume stored in the tiny interconnected pores of the pro-formed bearing, this type being known as an Oilite bearing.

As shown in FIG. 2, the bearing 11 is formed initially with a cylindrical bore 14 and a spherical outer surface 15. In casting the housing 19 about the bearing 11 in a suitable mold or die, not shown, the bearing 11 is first seated on a core pin and a one-piece housing 10 cast thereabout.

As a result, the housing It? is formed with a mating spherical surface bore 16. Desirably also and for facility in subsequent pivoting as will be explained, the altitude of the spherical seat 16 of the housing It) is lessthan that of the spherical segment surface 15 of the bearing 11.

The housing material metal as it cools, shrinks tightly around the bearing 11. It will be understood that no coating has been employed between the outer surface of the bearing 11 and the cast face of the housing 16 and.

ing pressure to the end of the bearing 11 in an axial direction and in a further radial direction from inside the bore 14 of the bearing 11.

Thus, the unit as shown in FIG. 2 is forced into the cavity 17. of the die 18 by means of a ram 19, the cavity of the die 18 being slightly smaller than the outer dimensions of the housing 10. The reduction in size of the housing as a result of the aforesaid compression, is such as .to. maintain the metal of the housing 19 within its elastic limits so that no permanent set is retained after removing the housing 10' from the die 18.

A shouldered punch 29 is then inserted into the bore 14 of the bearing 11 until the shoulder 21 thereof, contacts an end of the bearing 11. The punch which is endwise tapered as at 22 has a diameter slightly larger than that of the bore 14 so that it results in radial compression in an outward direction and opposite to the radial compression resulting from forcing the housing 10 into the die 18.

The shouldered punch is slightly out-of-round so that when forced into the bearing 11 it induces in the latter a slightly out-of-round shape which is retained therein due to compression of the bearing 11 beyond its elastic limit.

Thus, when the punch 20 is removed from the bearing 11, and the housing 10 is removed from the die 18, the housing 10 will return to its original size and contour but the bearing 11 will retain about 20% of its compression and slightly out-of-round condition. This set compression in the hearing, as a result of its resilient character, causes it to thereby separate from the confines of the spherical bore 14 of the housing ltl but to be retained therein in a pivotal manner. Further due to the resulting out-of-round character of the bearing 11, it is prevented thereby from spinning within the housing 10. At the same time, the strain of shrinkage of the housing 10 is relieved.

In a modified practice, the precast assembly of the housing 10 about the bearing 11 is forced into the cavity 17 of the die 18 in the manner previously described. However, in this case the cavity 17 of the die is slightly out-of-round so that the housing 10 becomes temporarily pressed to out-of-round condition. Thereafter, a shouldered punch similar to that of punch 21 is forced into the now slightly deformed bore 14 of bearing 11. However, in this case the punch 20 is cylindrical in cross.

section, except for a slight taper. The diameter of the punch 26 is of course slightly greater than that of the bore 14 in this modification so that the outer surface of bearing 11 becomes deformed to an out-of-round condition since it is restricted by the out-of-r-ound compressed housing from expanding equally. The sintered powdered metal composition of the bearing 11 while being resilient and returning to some of its original form, nevertheless does not return to its completely original form but remains with its outer surface deformed and out-of-round. Thus, while it becomes in this operation separated from the housing 10, it is nevertheless retained therein in a pivotal manner, firstly by the housing 10, and secondly is retained against spinning on its axis by reason of its out-of-round character and relatively small degree of separation from the confines of the housing 10.

In another modified method, similar but not fully equivalent results may be accomplished with or without restraining the housing 10. In this case, the die 18 having a cavity 17 may be employed but wherein the cavity 17 is of equal dimension to the outer diameter of the housing 10 so that it merely forms a seat therefor. In the alterna tive, other holding means may be employed. In this modified method, the sintered powdered metal bearing 11 only is compressed by restraining its axial movement at one end by means of, for example, the die 18, or other means, and a shouldered punch similar to punch 29 of slightly larger diameter than the inside diameter of the bore 14 is forced into the bearing 11. This compresses the bearing to a degree beyond its elastic limit and when the punch is withdrawn the bearing will spring back sufiiciently to relieve the restraining force of the compression of the housing It) and separate itself from the housing. In this case, the housing and bearing remain round, but the amount of expansion and spring-back is controlled to retain sufficient friction of the bearing 14 against the confines of housing 10 so as to prevent the bearing 11 from spinning on its axis While remaining pivotally retained in the housing 10.

However, due to the pivotability of the bearing 11 within the housing 10 in each case, it is possible to corn pensate for initial or subsequent minor misalignment of a shaft journaled in the bearing 11 and to thereby relieve undue stress on either the bearing or the shaft or both. The housing It needs only to be bolted in place by means of suitable bolts engaged through the holes 13 in the integral flanges 12 to provide a bearing surface for a rotatable shaft. Thus, the device of the present invention provides a self-aligning bearing surface with a simple means by fastening the bearing to a suitable support and eliminates the need for costly alignment since the unique construction and arrangement of the parts automatically provides for self-alignment and the assembly relieves undue stress of the engaged rotating shaft in the bearing through application of a ball-joint-like unit.

Although I have shown and described the preferred embodiment of my self-aligning pillow block and preferred method and means for forming the same, it will be understood by those skilled in the art that various changes may be made in the details thereof without departing from the spirit and scope of my invention as comprehended by the following claims.

I claim:

1. The method of making a self-aligning pillow block which comprises casting a onepiece rigid metal housing about a bearing composed of elastic sintered powdered metal material having a spherical outer surface and formed with a cylindrical axial bore to provide said housing with a spherical bore partially embracing and retaining. said bearing, and then subjecting said bearing to radial compression outwardly from within its bore to cause it to become fixedly compressed, and then removing said compressing forces to cause said bearing to become slightly separated from the internal surface of the housing while remaining pivotally disposed therein and frictionally retained against rotation on its axis.

2. The method of making a self-aligning pillow block which comprises casting a one-piece rigid metal housing about a bearing composed of elastic sintered powdered metal material having a spherical outer surface and formed with a cylindrical axial bore to provide said housing with a spherical bore partially embracing and retaining said bearing, thereafter compressing said housing, Within its elastic limit, about said bearing to radially compress the latter, and then while so compressed further subjecting said bearing to radial compression outwardly from within its bore to cause it to become fixedly compressed, and then removing said compression forces.

3. The method of forming a self-aligning pillow block which comprises radially compressing to out-of-round contour a bearing composed of elastic sintered powdered metal material initially having a spherical outer surface and formed with a cylindrical bore while disposed in a onepiece rigid metal housing cast thereabout having a spherical bore of lesser altitude than that of said bearing surface, and thereafter permitting said bearing to expand and to but partially return to its original contour and to thereby become spaced from and pivotally disposed within said housing while frictionally retained therein against spinning on its axis.

4. The method of forming a self-aligning pillow block which comprises disposing a bearing composed of elastic sintered powered metal material having a spherical outer surface and formed with a cylindrical bore over a core pin having a cylindrical outer diameter snugly seating said bearing, casting a one-piece rigid metal housing about said bearing to provide said housing with a spherical bore of lesser altitude than that of said bearing surface, thereafter withdrawing said core pin, compressing said housing to deform its spherical bore to out-of-round condition, within its elastic limit, about said bearing to radially compress the latter, then while so compressed subjecting said bearing to axial compression outwardly from within its bore to cause it to become fixedly compressed into a slightly out-of-round controur, and thereafter removing the compressing forces to permit the housing to fully return to its original contour and the bearing to but partially do so and to thereby become spaced from while remaining in pivotal disposition within said housing.

5. The method of forming a self-aligning pillow block which comprises disposing a bearing composed of elastic sintered powdered metal material having a spherical outer surface and formed with a cylindrical bore over a core pin having a cylindrical outer diameter snugly seating said bearing, casting a one-piece rigid metal housing about said bearing to provide said housing with a spherical bore of lesser altitude than that of said bearing surface, thereafter withdrawing said core pin, compressing said housing, within its elastic limit, about said bearing to radially compress the latter, then while so compressed subjecting said bearing to axial compression and to further uneven radial compression outwardly from within its bore to cause it to become fixedly compressed into a slightly out-of-round contour, and thereafter removing the compressing forces to permit the housing to fully return to its original contour and the bearing to but partially do so and to thereby become spaced from while remaining in pivotal disposition within said housing.

6,. Means for forming a self-aligning pillow block wherein a one-piece metal housing is case about a preformed sintered powdered metal bearing formed with a. cylindrical bore and a spherical outer surface, comprising a die for radially compressing the housing about the bearing, and a punch for disposition within said bearing to resiliently radially expand it to slightly out-of-round condition.

7. Means for forming a self-aligning pillow block wherein a one-piece metal housing is case about a preformed sintered powered metal bearing formed with a cylindrical bore and a spherical outer surface, comprising a die for radially compressing the housing to out-ofround contour about the bearing, and a punch for disposition within said bearing to resiliently radially expand it to said slightly out-of-round contour.

8. Means for forming a self-aligning pillow block wherein a one-piece metal housing is cast about a preformed sintered powdered metal bearing formed with a cylindrical axial bore and a spherical outer surface, comprising a die formed with a cavity for radially compressing the housing about the bearing, within the elastic limit of the housing metal, and a shouldered punch for disposition within said bearing to axially compress it and to further radially expand it beyond its elastic limit.

9. The method of making a self-aligning pillow block which comprises casting a one-piece rigid metal housing about a bearing composed of elastic sintered powdered metal meterial having a spherical outer surface and formed with a cylindrical axial bore to provide said housing with a spherical bore partially embracing and retaining said bearing, and then subjecting said bearing to axial compression to cause it become fixedly compressed, and then removing said compressing forces to cause said bearing to become slightly separated from the internal surface of the housing while remaining pivotally disposed therein and frictionally retained against rotation on its axis. t

References Cited by the Examiner UNITED STATES PATENTS 2,626,841 1/5 3 Potter 30872 2,728,975 1/ 5 6 Potter.

2,894,789 7/59 Tracy 308-72 2,997,775 8/ 61 Pennala.

WHITMORE A. WILTZ, Primary Examiner.

FRANK SUSKO, Examiner.

Claims

1. THE METHOD OF MAKING A SELF-ALIGNING PILLOW BLOCK WHICH COMPRISES CASTING A ONE-PIECE RIGID METAL HOUSING ABOUT A BEARING COMPOSED OF ELASTIC SINTERED POWERED METAL MATERIAL HAVING A SPHERICAL OUTER SURFACE AND FORMED WITH A CYLINDRICAL AXIAL BORE TO PROVIDE SAID HOUSING WITH SPHERICAL BORE PARTIALLY EMBRACING AND RETAINING SAID BEARING, AND THEN SUBJECTING SAID BEARING TO RADIAL COMPRESSION OUTWARDLY FROM WITHIN ITS BORE TO CAUSE IT TO BECOME FIXEDLY COMPRESSED, AND THEN REMOVING SAID COMPRESSING FORCES TO CAUSE SAID BEARING TO BECOME SLIGHTLY SEPARATED FROM THE INTERNAL SURFACE OF THE HOUSING WHILE REMAINING PIVOTALLY DISPOSED THEREIN AND FRICTIONALLY RETAINED AGAINST ROTATION ON ITS AXIS.