JPS6058124B2 - Trolley wheel assembly and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to trolley wheels, and more particularly to an improved trolley wheel that has a high load-bearing capacity and is wear-resistant and durable, and which eliminates the manufacturing difficulties and expense of the prior art. The present invention relates to a method of manufacturing an improved trolley wheel that avoids the above.

Trolley wheels have been used for many years in many industries, especially overhead and other conveyors.

Such wheels typically support suspension brackets that transport articles through various processing steps. For many years, metal trolley wheels were used, but such trolley wheels were subject to wear, corrosion, deterioration, and were noisy during operation. In recent years,
Trolley wheel assemblies combining metal and plastic were devised and greatly advanced the industry due to their many advantages.

One such trolley wheel is Frederik
Frederick R. Sytsma
), '6 Sanitary Antifriction Trolley Wheel (SANITARYANTIFRICTIO
No. 3,971,601, entitled NTROLLEYWHEEL) 53.

The trolley wheel utilizes a pair of metal outer bearing races mounted adjacent to a central opening in an anti-friction plastic trolley wheel, with an inner race assembly extending through the opening and a space between the inner and outer races. A pair of rows of anti-friction ball bearings are arranged. The outer race is spaced apart by a portion of the plastic wheel. A difficulty encountered with such prior art wheels is that the portion of the wheel that separates the outer race is critical to bearing spacing and therefore to the proper functioning of the trolley wheel assembly.

Due to material shrinkage during wheel manufacture, it is difficult to obtain the exact dimensions needed for the wheel, particularly in the area between the outer races, prior to insertion of the outer races. Another difficulty encountered during use was the rotation of the outer metal bearing race against the anti-friction plastic wheel.

Such races also have been difficult to maintain axial alignment with the wheels. As the race rotated relative to the wheel, it generated heat and abrasion, shortening the life of the wheel. Excessive wear causes bearing misalignment. Also, the shape of the prior art outer race requires drawing of a portion of the race, which means that the material used must have sufficient ductility for said drawing.

Providing sufficient ductility to the metal material precluded the use of materials with high hardness and wear resistance and limited the load-bearing capacity of the assembly. Therefore, we maintain the advantages of recently designed metal-plastic trolley wheel assemblies useful in sanitary overhead conveyors, yet manufacture and
A need exists for an improved trolley wheel assembly that overcomes the above maintenance and use problems.

Accordingly, the present invention provides an improved trolley wheel assembly that is easier to manufacture and has a higher load carrying capacity than previously known assemblies, yet maintains certain advantages of previously known assemblies.

The present invention is particularly suited to hygienic conditions and frequent steam cleaning, such as in the food processing industry where assemblies are exposed to high heat and moisture conditions and must be used for long periods of time without corrosion, deterioration and failure. Extremely useful in conveyors that require In broader aspects, the trolley wheel assembly of the present invention includes an anti-friction plastic trolley wheel having a central opening with a through shaft, and a pair of annular metal outer wheels disposed rear-to-back within the opening. bearing races, each outer bearing race including a portion adapted to receive an anti-friction bearing member for rotational support of the wheel and the outer race, and further for preventing relative rotation of the outer race with respect to the wheel. with a concave area.

The plastic wheel also includes an engagement portion that engages a recessed area on the outer race to prevent relative rotation of the wheel and race and to prevent axial movement of the outer race from the rear abutment position. an inner bearing bearing race having a pair of inner raceways in the central opening aligned with the shaped portion of the outer bearing race; and an inner bearing raceway disposed between each outer bearing race and the inner raceway for rotational support of the wheel and the outer race. An anti-friction bearing member is provided. In more detailed aspects of the wheel assembly, the plastic wheel is molded around the outer race and includes a portion extending on the axially outer end surface of the outer race to hold the outer race in a rear abutment position; It also includes an integral portion extending into a scallop formed on the axially extending flange of the outer race to prevent relative rotation of the race with respect to the wheel.

A method of manufacturing an anti-friction trolley wheel is also disclosed which provides an easier and simpler method than previously known.

A pair of annular metal outer bearing races is provided including a portion adapted to receive the bearing mechanism and a recessed area to prevent relative rotation of the race with respect to the wheel. The race is disposed in engagement with each other such that the shaped portions are axially aligned, and a plastic wheel is disposed about the race such that the wheel contacts and supports a radially outer end surface of the race. Ru. The wheel fills the gap between the outer races but does not separate them, contacts a concave area of the outer race to prevent relative rotation of the race and the wheel, and projects axially beyond at least a portion of the outer race. Hold the outer race in axial alignment. The wheel assemblies and methods of making the same are advantageous because the races are prepositioned in engagement with each other and the wheels are molded or otherwise disposed around them so that the exact portions of the plastic wheel that space the outer races are avoid difficult dimensioning. The assembly is very durable and wear resistant since relative rotation between the outer race and the plastic wheel is prevented by the concave area, and the races are held axially in engagement with each other by the portion of the wheel. Proper alignment of the bearings is ensured. The shape of the outer bearing race eliminates the need for drawing during manufacturing and allows the use of hardened materials.
A higher load-bearing capacity is obtained for the assembly. In addition to each of the above advantages, the assemblies are frequently steam cleaned and are therefore free from high heat and moisture without all the corrosion, breaking, chipping and other deterioration that can contaminate the food being conveyed by such assemblies. It maintains other advantages useful for hygienic conveyors, such as in the food processing industry, where they must be exposed to These and other objects, advantages and features of the invention will become more apparent from the following description in conjunction with the drawings. Referring to the drawings, FIGS. 1-3 illustrate a preferred embodiment 10 of the trolley wheel assembly of the present invention, which includes a pair of identical, annular, metal outer bearing races 12;
and a multi-piece inner race assembly 40 extending through the wheel and outer race combination.

A pair of rows of anti-friction ball bearings 80 are positioned between the axially and radially aligned outer and inner races to allow the wheel and outer race combination to rotate about the multi-piece inner race assembly. I support it. As shown in FIG. 1, assembly 10 is designed to be supported on the upper end of trolley bracket 11, with the bracket depending from the wheel assembly.

The wheel 30 itself includes an angled outer circumferential surface, adapted to accommodate the angled surface of the lower flange of an I-beam commonly used on overhead conveyors. A bracket 11 extends on one open side of the I-beam and another bracket 11 and wheel assembly extends on the opposite side of the I-beam.
The two brackets are coupled to hold the wheel in alignment with and moving along the beam.

An annular metal outer bearing as shown in Figures 1 and 2.
Races 12 are used in pairs within a single wheel 30.

Each race 12 is preferably stamped from precipitation hardened stainless steel to provide a durable, long-life support surface for the row of ball bearings 80. 12 races each
includes a radially extending annular flange 14 having a circular central opening 16 . The flange 14 is a curved transition area 1
It is joined to an axially extending annular flange 20 via 8, which flange 20 has an outer end surface 22 lying in one plane.
The curve transition area 18 has a cross-sectional shape of a portion of a circle, and has a first
It is adapted to match the spherical profile of a ball bearing 80 received therein as shown. The outer end surface 22 of the axially extending flange 20 of each race also preferably includes four equally spaced curved scallops.
lOp) or a recess 24.

The recesses 24 tightly engage a correspondingly shaped portion of the plastic wheel 30 to prevent relative rotation between each race 12 and the wheel 30 when in place within the wheel, and to prevent axial movement and/or movement of each race 12. or prevent separation. As shown in FIGS. 1-3, wheel 30 receives race 12 in rear-to-back abutment relationship within its central opening 32. As shown in FIGS. The radial flanges 14 are joined together and the axial flanges 20 extend away from each other. Although wheel 30 is shown as a separately manufactured part in FIG. 2, in actual manufacture, wheel 30 is injection molded around a pair of prepositioned races, as shown in FIGS. 10 and 11. Ru. However, if the material of the wheel is flexible enough to allow insertion of the race, and each portion of the wheel can be engaged with the recess 24 and outer end surface 22 of the flange 20, then the wheel can be made into a race. It is also possible to mold the race separately from the race and then assemble it to the wheel. In either case, the wheel 30 includes an annular, generally square-shaped cross-sectional portion 34 that fits between the curved transition areas 18 of the engagement races and completely secures the races without separating them. To support.

Furthermore, on both sides of the central opening 34 there are provided areas 36 having a shape that matches the shape of the outer end surface of the race 12, and a radially extending flange 37 at each axial end of the wheel 30;
38 are provided. The flanges 37, 38 have an axially extending curved protrusion 39 extending on the outer end surface 22 of the race 12 to tightly engage the outer end surface 22 of the race to maintain the axial position of the race. These protrusions are in the recess 3
4, it is generally parallel to the axis of the wheel 30 and fits into the recess 24 to prevent relative rotation of the wheel and race. The radially inner end surfaces of the flanges 37, 38 and the protrusion 39 are in the same plane as the inner surface of the axial flange 20 of the race 12 to prevent interference with the bearing 80 (see Figs. 1, 4, and 6). ). Preferably, the wheel 30 is one
．． E. DupOntdeNemOursandComp
It is formed from a thermoplastic material such as an acetal resin sold under the trademark Delrin '5 by Any.

This material is easily injection molded as described below and when cooled forms a durable, abrasion resistant, high load bearing wheel that is particularly abrasion resistant when used in conveyors and is easily moved. It is possible.

This material has sufficient strength to hold the races 12 in the proper engaged position and is substantially silent when operated in contact with a conventional metal 1 beam. As shown in FIGS. 1-3, an axially extending inner race assembly 40 is preferably formed entirely of stainless steel and includes a solid shaft 42 having an enlarged head 44.
tapers inwardly at section 46 to a constant diameter shaft portion 48 .

The free end of shaft 42 has a thread 50 adapted to receive a nut for securing the shaft and thus the entire wheel assembly to bracket 11 (FIG. 1).
. A second, hollow, inner race member 52 is disposed on shaft 48 abutting head 44 and tapered section 46.
is arranged, the member 52 having an enlarged diameter portion 54 and a concave surface 56 forming an inner raceway, the concave surface 56 having a spherical ball shape.
The outer race 1 is complementary to the outer shape of the bearing 80 and
It has the same radius of curvature as the curve transition area 18 of No. 2.

Concave surface 56 merges with a constant diameter portion 58 terminating in a radial end surface 60 . Member 52 has an inner diameter that matches the outer diameter of shaft 48 and includes an enlarged tapered opening 55 that engages a correspondingly shaped enlarged head 44 to prevent movement of member 52. The third, hollow, cylindrical member 62 includes an enlarged diameter section 64 that curves inwardly to a reduced diameter section 68 to form a contoured track for a ball bearing 80.

Portion 68 terminates in a radial end face 70 . member 62
fits over shaft 48 and abuts end surface 60 of member 52 and has an inner diameter that matches shaft 48 . Inner race members 52, 62 are retained on the shaft by a retainer assembly that includes split elastic clips 74. Clip 74 fits into alignment grooves 75 and 76 formed on the outer diameter of shaft 48 and the inner diameter of member 62, respectively. One of the grooves 75 and 76 is slightly wider than the clip 74;
A small amount of axial movement is provided between member 62 and shaft 48 to allow member 52 to be pressed tightly against end face 70, which also allows member 52 to press against head 44.
The two parts are attached to each other so that they function as a unit without relative rotation. The width of the member 62 is such that when assembled into the wheel 30, it protrudes from the outer or axial side surface of the wheel (FIG. 1). This causes bracket 11 to engage member 62 and press it tightly against end face 60 of member 52. Additionally, at least one of the grooves 75, 76 is deep enough to receive the entirety of the clip 74 when the member 52 is on the shaft 48 and the member 62 is seated onto the clip 74 on the shaft 48. have The structure of the multi-component inner race assembly 40 was developed by D on August 2, 1977.
everW. C℃ONN granted to Schmidt
ECTION APPARATUSFORrVlULTI
It follows the concept disclosed in US Pat. No. 4,039,233 entitled PIECEBEARING RACEO.

7-9, alternative embodiments of axially extending inner race assemblies are shown, all of which may be used with the improved trolley wheel structure of the present invention.

All of these alternative inner race assemblies are preferably formed from stainless steel and are similar to those described in U.S. Pat. No. 4,039.
A split, elastic, retainer clip 74 is utilized in accordance with the concepts disclosed in the '233 patent. i.e., placing the clip in a fixed position on one of the members of the assembly, allowing slight axial movement of the members relative to each other, and - having dimensional characteristics that ensure the clamping of the members so that they function as a unit. The clip sits within the groove. In FIG. 7, the solid shaft 85 has an enlarged head 86 and
It has a curved inner raceway section 87 shaped to match the spherical shape of ball 80 and a constant diameter section 88 and is inserted through opening 16 in bearing race 12 .

A coaxial shaft 89 extends from the end surface of section 88;
A screw 90 is provided. A second inner race member, identical to member 62 described above, fits over shaft 89 and abuts axial end face 91 of section 88 and is retained on shaft 89 by resilient clip 74 in the manner described above. There is. In FIG. 8, the inner race assembly includes a bushing 95 having an outer surface having the same shape as the solid shaft 85 of FIG.

However, in this case member 95 is hollow and adapted to receive a shaft or stud, such as shaft 42 of FIG. Member 95 includes a reduced diameter cylindrical surface 96 that receives inner race member 62 as described in connection with FIGS. The member 62 is held on the cylindrical surface 96 by the elastic clip 74 as described above, and protrudes slightly from the end face of the member 95 and the side surface of the wheel 30, so that both members are tightly pressed by the bracket. There is. In Figure 9, 3
The inner race assembly of the member configuration is connected to the opening 1 of the race 12.
6.

This assembly is similar to that in FIG.
Two head bushings 9 are used instead of the bushing 95 shown in the figure.
8,99 are used. Member 62 abuts the end face of member 98 and presses this member onto the head end of member 99 to hold all the members together tightly, while elastic clip 74 engages between members 99 and 62 to retain the assembly. do. In FIG. 8 or 9, a separate support shaft is inserted through the inner diameter of the inner bushing to hold the assembly in the desired condition. Next, referring to Figures 10 and 11,
A preferred method and apparatus for manufacturing the improved trolley wheels shown in FIGS. 1-9 is shown.

The wheel is preferably injection molded in a mold apparatus 100 that includes an upper movable mold section 102 and a lower fixed mold section 140. Sections 102, 140 engage each other along parting line P as shown in FIG. Upper mold section 102 includes an upper plate 104 that is secured to a lower plate 106 by conventional fastening means or welding.

A central hollow block 108 is disposed within the lower plate 106 and is pressed onto the upper plate 104 by shoulders 110. A reciprocating cylindrical member 114 is disposed within a pair of central openings 112 of block 108, having a hollow cylindrical end portion 116 and a central cylindrical recess 118 therein. The reciprocating member 114 is biased downwardly by springs 122 disposed within the top plate 104 which engage the upper surface of the member 114 such that the downward movement of the member 114 is caused by the shoulder 1
20. The upper part of mold cavity C is block 1
08 and as described below, a reciprocating member 114
is moved downwardly therethrough to assist in forming the mold cavity and prepositioning the outer race 112. The lower mold section 140 includes a base plate 142 that is secured to a central plate 144 and that is connected to the base plate 142.
44 is fixed to the upper plate 146, and the plate 146
is the central opening 1 for receiving the lower hollow block 148.
47 and the block 148 is secured to the plate 144 by a shoulder 150.

The block 148 includes a lower portion of a mold cavity C formed therein and an upright cylinder 152 in the center of each lower mold portion. The cylinder 152 includes a shoulder 154 shaped to match the shape of the portion 18 of the outer race 12 onto which the portion 18 is mounted during manufacture. The upper end of the cylinder 152 matches the diameter of the recess 118 of the reciprocating member 114. A plurality of protruding rods 156 fixed to a reciprocating protruding plate 158,
It is inserted into cavity C through aligned openings through plate 144 and block 148.

The end of rod 156 is flush with the bottom of the cavity when retracted, but can be moved upwardly by ejector plate 158 to eject the molding wheel assembly from cavity C after the molding process. Upper mold section 1 to form the wheel
02 is removed from the lower mold section 140 along the parting line.

A pair of outer races 12 are inserted onto the cylinder 152 in an axially aligned, back-to-back butt relationship such that the lower race portions 18 engage the shoulders 154 of the cylinder.
Upper mold section 102 is then attached and engaged with lower mold section 140 so that portion 116 is received by upper race portion 18 seated on cylinder 152. The cylinder 152 engages the recess 118 to axially align the cylinder and the reciprocating member 114. spring 12
2 biases member 114 downwardly to hold each race tightly together during molding. Heat-molten plastic, preferably the acetal resin described above, is then forced into each mold cavity through nozzle 160 and sprue 162, 164 (FIG. 11) to fill the mold cavity. The injected molten plastic is allowed to cool and solidify to hold the race in its pre-positioned position, and then when the upper mold section 102 is removed the ejector rod 156 is reciprocated through the ejector plate 158 to displace the forming wheel. stand out As can be seen in FIG. 10, the plastic is molded tightly around the race 12 to form a middle portion 34 of the rear face of the race as well as flanges 37, 38 which, as previously described, are located on the inner side of the race. It is flush with the ball bearing contact surface.

This method eliminates the need to precisely dimension the center portion of the wheel before assembling the races, and also securely bonds the races together so that the races maintain proper axial and radial orientation throughout the life of the wheel. maintain alignment and engagement. Of course, the race can be integrated into the wheel by pre-positioning it in the mold cavity C as described above.
It is also possible to mold the wheel from a flexible plastic rubber or other material that can be unshaped and flexibly placed around a pair of prepositioned races. In this case, in order to form only the wheel 30, the central upright cylinder 15 is
2 and the lower end 116 of the reciprocating part 9 member 114 is changed in shape, and the parts 32, 34 of the wheel for receiving the race,
36 to be properly molded. Accordingly, the present invention maintains the advantages of plastic-metal wheel assemblies for use in sanitary conveyors, yet improves the load carrying capacity, wear resistance, durability and ease of manufacture of the assembly. An improved trolley wheel assembly is provided.

While several forms of the invention have been shown and described, other forms will be apparent to those skilled in the art. It is therefore to be understood that the embodiments shown and described are for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of one embodiment of the improved trolley wheel assembly of the present invention secured to the upper end of a typical overhead conveyor trolley bracket. 2 is an exploded perspective view of the trolley wheel assembly of FIG. 1; FIG. FIG. 3 is an end view of the trolley wheel assembly of FIGS. 1 and 2. FIG. FIG. 4 is a cross-sectional view of the trolley wheel and outer race. Figure 5 shows V in Figure 3.
It is a partial sectional view along the -V line. Figure 6 is the same as in Figure 4.
It is a sectional view taken along the line -■. FIG. 7 is a cross-sectional view of a trolley wheel assembled with another embodiment of an axial inner race assembly. FIG. 8 is a cross-sectional view of a trolley wheel assembled with yet another embodiment of an axial inner race assembly. FIG. 9 is a cross-sectional view of a trolley wheel assembled with yet another embodiment of an axial inner race assembly. FIG. 10 is a sectional view of a preferred injection molding apparatus used to manufacture the trolley wheel of the present invention. FIG. 11 is a plan view of the lower half of the injection molding apparatus as viewed in the direction of line 1--M in FIG. 10. 10... Trolley wheel assembly, 11... Trolley bracket, 12... Outer race, 30...
・Plastic trolley wheel, 42・Uyaft,
52...Inner race member, 62...Inner race member, 74...Clip, 80...Ball
Bearing, 100... Injection molding device, 102
...Movable section, 108...Central hollow block, 114...Reciprocating molded member, 1
22...Spring, 140...Fixed section, 148...Cavity block, C...
・Mold cavity, 156...Protruding rod, 158...
protruding board.

Claims (1)

Claims: 1. An anti-friction plastic trolley wheel 30 having a central opening with a through shaft; a pair of annular metal outer bearing races 12 disposed rear-to-back within the central opening; and each said outer bearing race has a portion 18 adapted to receive an anti-friction bearing member 80 for rotational support of said wheel and said outer bearing race to prevent relative rotation of said outer bearing race with respect to said wheel. the wheel includes a recessed area 24 for each of the outer bearing races to prevent relative rotation of the outer bearing race with respect to the wheel and to prevent axial movement of the outer bearing race from the rear abutment position. engaging portions 37, 38 that engage said recessed areas of the outer bearing race;
39; an inner bearing race assembly 40 extending axially within the central aperture and having a pair of inner raceways aligned with the shaped portion of the outer bearing race; A trolley wheel assembly comprising an anti-friction bearing member disposed between each of the outer bearing races and the inner raceway for rotationally supporting the races; 2. The trolley wheel assembly of claim 1, wherein the recessed area and the engaging portion of the outer bearing race extend parallel to the axis. 3 including an axially extending flange 20 on each said outer bearing race, said flanges 20 extending away from each other; said engaging portion abutting an end face of each said axial outer bearing race flange; 3. A trolley wheel assembly as claimed in claim 2 including radially extending flanges 37,38. 4. Each said outer bearing race includes an annular radially extending flange 14 integral with and generally perpendicular to said annular axial flange 20, said radially outer bearing race flanges being generally mutually related. of the claim 1, wherein the shaped portions 18 of each bearing race include portions of the annular radial and axial flanges and a curved, annular transition area therebetween. A trolley wheel assembly according to scope 3. 5 the shaped portion 18 of the outer bearing race includes an inner surface that engages the anti-friction bearing member; the radially extending flanges 37, 38 of the engaging portion extend in the axial direction; 5. A trolley wheel assembly as claimed in claim 4 in which the inner surface of the outer bearing race flange is coplanar. 6 said recessed area 24 includes at least one scallop provided on the edge of each of said axially extending flanges 20 of said outer bearing race; Flanges 37, 38
6. The trolley wheel assembly of claim 5, wherein said scallop includes an axially extending projection (39) extending into and mating with said scallop. 7 said recessed area 24 includes an axially extending recess in each said outer bearing race; said engagement portion extends into and mates with an axially extending recess in said outer bearing race; A trolley wheel assembly according to claim 1 including a protrusion (39). 8 said engagement portion also includes radially extending flanges 37, 38 that engage the radially extending portion 22 of the axially outer end of said outer race, and said axial protrusion 39 and radially extending flanges 37, 38,
8. The trolley wheel assembly of claim 7, wherein the trolley wheel assembly is flush with a surface of the outer bearing race that engages the anti-friction bearing member. 9 said wheel 30 is molded around said outer bearing race 12 pre-positioned in said rear-butting relationship, said wheel having a V-shaped cross-sectional shape that engages a radially outer end surface of said outer bearing race; The trolley wheel assembly of claim 1, including a central portion (34), said engaging portions (37, 38, 39) engaging said axially outer end surface (22) of said outer bearing race. 10. The axially extending inner bearing race assembly 40 is a multi-part inner bearing race assembly forming a separate inner raceway shaped to match the shaped portion of the outer bearing race. 2. The trolley wheel assembly according to claim 1. 11 retaining assemblies 74, 75 for holding the multi-part inner bearing race assembly 40 together;
76, wherein the retention assembly allows axial movement between portions of the inner bearing race assembly;
11. The trolley wheel assembly of claim 10, wherein said portions of said inner bearing race assembly are adapted to be clamped together. 12 (1) providing a pair of annular metal outer bearing races 12 each having a flange 14 extending generally radially in the completed wheel assembly and a flange 20 extending generally axially in the completed wheel assembly; (2) arranging the races in a back-to-back relationship such that the radial flanges engage each other parallel and the axial flanges extend away from each other; (3) plastic around the locating races; A wheel 30 is positioned such that the plastic fills the gap between the races but does not separate the races from the rear-butting relationship and extends over the axial end faces 22, 24 of the axial flanges. and the rear butt race avoids the need for precise sizing of the wheel portion therebetween. 13. Manufacturing a trolley wheel according to claim 12, comprising forming the wheel around the race by molding it from a flowable plastic and allowing the plastic to settle and solidify around the race. Method. 14 positioning the outer bearing race on an upright central support 152 in the mold cavity c and engaging a retaining member 114 against the race to hold the race against the central support during molding; 14. A method of manufacturing a trolley wheel according to claim 13, which comprises combining. 15. parts of the retaining member and the central support are arranged flush with the radially inner end face of the axially extending flange of the outer bearing race and are used as part of the mold cavity, so that the wheel is portions 37, 38 that engage the axial end faces 22, 24 of the axial flange, terminating flush with the inner end face of the axial flange;
15. A method of manufacturing a trolley wheel according to claim 14, wherein the trolley wheel is molded to include: 39. 16. The method of claim 14, wherein the retaining member is biased into engagement with the race to hold the race against the central support. 17. A method of manufacturing a trolley wheel as claimed in claim 12, including axially aligning the outer bearing race before positioning the wheel around the outer bearing race.