Bearing cap assembly

The present invention concerns a unique method and apparatus for machining a bearing cap assembly of the type typically utilized in a universal joint mechanism. The bearing cap assembly includes an open-ended bearing cap having a closed end wall with an outer surface secured to a mounting plate located generally parallel to the end wall and having spaced apart opposite end portions extending outwardly past the bearing cap. The present invention is specifically concerned with machining the end portions of the mounting plate extending outwardly from the bearing cap to produce spaced apart machined surfaces which can be utilized to attach the bearing cap assembly to an associated yoke arm. The present invention also concerns a unique bearing cap assembly which is produced by the disclosed method and apparatus.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a bearing cap and mounting plate 
assembly of the type typically utilized in a universal joint mechanism 
and, in particular, to a method and apparatus for machining the surfaces 
of the mounting plate which are adapted to engage an associated universal 
joint yoke arm. 
Bearing cap assemblies of the type utilized in a universal joint mechanism 
typically include an open ended cup-shaped member having a cylindrical 
sidewall and a closed end wall which is securely attached to an associated 
mounting plate. The mounting plate is utilized to secure the bearing cap 
relative to the yoke arms of a universal joint yoke assembly. Examples of 
such bearing cap assemblies are disclosed in U.S. Pat. Nos. 2,291,436 and 
2,315,006. 
One of the difficulties in producing universal joint bearing cap assemblies 
relates to the strict tolerances which much be observed during the 
manufacturing operation. For example, typically, the inner surface of the 
bearing cap sidewall, which provides an outer bearing race for an 
associated roller bearing unit, must be precisely located relative to a 
pair of spaced apart mounting holes provided in the mounting plate. Also, 
the surfaces of the mounting plate which are adapted to engage cooperating 
mounting surfaces formed on the associated yoke arm must be precisely 
located relative to the inner surface of the end wall of the bearing cap. 
In the past, in order to maintain such tolerances, it has been necessary to 
utilize a drill press unit with an associated cutting tool for machining 
the mounting plate surfaces. While such a machining operation produces a 
quality part, the production rate of such an operation is relatively slow. 
U.S. Pat. No. 2,291,436 discloses the use of a pair of spaced apart 
broaches for machining spaced apart mounting surfaces on the attaching 
strap of a universal joint bearing cap. However, the broaching operation 
as disclosed in this patent does not lend itself to a high production 
operation. 
SUMMARY OF THE INVENTION 
The present invention concerns a unique method and apparatus for machining 
a bearing cap assembly which can be utilized, for example, in a universal 
joint mechanism. The present invention also concerns a unique bearing cap 
assembly which is produced by means of the method and apparatus disclosed 
herein. 
In particular, the bearing cap assembly includes an open ended bearing cap 
having an axis and including a generally cylindrical sidewall parallel to 
the axis, and a closed end wall attached to the sidewall and perpendicular 
to the axis. A mounting plate is located generally parallel to and is 
securely attached to the end wall of the bearing cap. The mounting plate 
includes a mounting surface in facing relationship with the bearing cap. 
The mounting surface includes a central surface portion secured to the 
outer surface of the end wall and two spaced apart end portions located on 
opposite sides of the central surface portion and spaced outwardly past 
the sidewall of the bearing cap. The end surface portions are spaced from 
one another by a distance at least as great as the outer diameter of the 
bearing cap and are raised relative to the adjacent areas of the central 
surface portion. 
In the method of the present invention, the open end of the bearing cap is 
first placed on a support pin having a stop surface adapted to engage the 
inner surface of the end wall of the bearing cap. Next, the support pin 
having the bearing cap assembly supported thereon is moved in a 
predetermined direction with the mounting plate located in a plane 
generally parallel to the direction of travel. As the support pin and the 
bearing cap assembly are moved, a force is exerted on the bearing cap 
assembly in a direction perpendicular to the direction of travel to urge 
the inner surface of the end wall of the cap into positive engagement with 
the stop surface of the support pin. While the cap is urged toward the 
support pin, the end portions of the mounting plate extending outwardly of 
the bearing cap are machined to produce spaced apart machine surfaces 
generally parallel to the direction of travel of the bearing cap assembly. 
As will be discussed herein, the apparatus of the present invention 
includes means for performing the above described method steps.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown a perspective view of a bearing cap and 
mounting plate assembly 10 having a structure according to the present 
invention. A sectional view of the bearing cap assembly 10 of FIG. 1 is 
shown in FIG. 2. The bearing cap assembly 10 includes an open ended 
bearing cap 12 (having an axis A) which is secured to a mounting plate 14 
generally perpendicular to the axis A. The bearing cap 12 includes a 
generally cylindrical sidewall 16 and a closed end wall 18. The inner 
surface 16a of the sidewall 16 is machined and provides an outer bearing 
race for a roller bearing unit (not shown) for rotatably supporting one 
end of a universal joint trunion (not shown). The extreme outer end 
surface of the trunion is adapted to abut against a machined surface 18a 
formed on the inner side of the end wall 18. The outer surface of the end 
wall 18 is securely fastened by welding, for example to the mounting plate 
14. The mounting plate 14 is provided with spaced apart apertures 14a and 
14b for receiving suitable threaded fasteners for fastening the bearing 
cap and mounting plate assembly and to an associated yoke arm (not shown) 
of a universal joint assembly. 
The present invention is specifically concerned with a method and apparatus 
for machining a pair of spaced apart mounting surfaces 14c and 14d which, 
as viewed in FIG. 2, face upwardly toward the open end of the bearing cup 
12. The surfaces 14c and 14d are located on opposite sides of the bearing 
cap 12 and are spaced outwardly past the sidewall of the bearing cap. The 
surfaces 14c and 14d are spaced apart by a distance S which is at least as 
great as the outside diameter D of the bearing cap, and are raised 
relative to the adjacent surface portions 14e and 14f respectively. Prior 
to machining, the mounting plate 14 includes unfinished end surface 
portions which are shown in phantom in FIG. 2 and are represented by 
reference numerals 14g and 14h. As will be discussed, a bearing cap 
assembly having such a structure enables the mounting surfaces 14c and 14d 
to be machined by a pair of spaced apart, longitudinally extending 
stationary broaches as the bearing cap is moved in a longitudinal path. 
It should be noted that the machining operation of the surfaces of 14c and 
14d must be performed within a strict tolerance range. More specifically, 
the distance T (shown in FIG. 2) between the machined surface 18a on the 
inner side of the end wall 18 and the machined surfaces 14c and 14d must 
be within a predetermined tolerance range in order to ensure proper 
operation of the universal joint mechanism. 
As shown in FIG. 1, the mounting plate 14 is provided with a flat surface 
portion 20a and spaced apart angled portions 20b and 20c which, as will be 
discussed, are utilized to properly orient the bearing cap assembly prior 
to the machining operation. The flat surface portion 20a is spaced 
outwardly from the outer sidewall of the bearing cap by a distance B. 
The method and apparatus of the present invention enables the surfaces 14c 
and 14d of the mounting plate to be machined within the predetermined 
tolerance range while also achieving a relatively high rate of production. 
There is shown in FIG. 3 a schematic drawing illustrating the overall 
structure of the machine apparatus of the present invention. Basically, 
the apparatus includes a plurality of individual transport cars 30 which 
are interconnected by an endless chain 32 (the lower portion of which is 
represented by dashed line 32a). The transport cars 30 each include a 
support pin 34 utilized to support a separate bearing cap assembly 10 with 
the open end of the bearing cup and the unfinished surfaces 14g and 14h 
facing downwardly. The chain 32 is driven by an external drive source (not 
shown) and is utilized to move the cars 30 in a linear path at a 
predetermined rate of speed. 
Initially, and prior to any machining of the surfaces 14g and 14h, the 
transport car 30 carrying the bearing cap assembly having unfinished 
surfaces 14g and 14h is moved through a positioning means 36. A limit 
switch unit 38 is located at the forward end of the positioning means to 
ensure that the bearing cap assembly 10 has been properly placed on the 
associated support pin 34. As will be discussed, the positioning means 36 
includes a flipper assembly which is utilized to properly orient the 
bearing cap assembly on the support pin. Once the bearing cap assembly has 
been properly oriented, the car 30 transports the bearing cap assembly to 
a machining tunnel 40 which, in the preferred embodiment of the invention, 
includes a pair of longitudinally extending spaced apart broach cutters 
(not shown in FIG. 3) for machining the surfaces 14c and 14d. 
One of the important features of both the method and apparatus of the 
present invention is related to the manner in which the bearing cap 
assembly 10 is held in position during both the positioning and the 
machining operation. More specifically, referring to FIG. 4, which is a 
section taken through the machining tunnel 40 along the line 4--4 of FIG. 
3, there is shown a spring bias hold down bar 42 which is utilized to urge 
the inside machined surface 18a of the end wall 18 into positive 
engagement with an upper stop surface 34a provided on the upper end of the 
support pin 34 of the car 30. As shown in FIG. 4, the machining apparatus 
includes an upper main body 44 having a downwardly facing longitudinally 
extending slot 44a formed therein for receiving the hold down bar 42. A 
spring cavity 44b extends upwardly from the slot 44a for receiving a 
helical coil spring 46 for exerting a downward force on the hold down bar 
42. The hold down bar 42 is provided with a lower surface 42a which 
engages an outer upwardly facing surface 14m of the mounting plate 14. 
Also shown in FIG. 4 are a pair of spaced apart broaches 48a and 48b which 
are securely mounted relative to the main body 44 and are utilized to 
machine the surfaces 14c and 14d as the support pin 34 having the bearing 
cap assembly 10 mounted thereon is moved through the machining tunnel. 
Referring to FIGS. 5 through 8, the transport cars 30, the positioning 
means 36, and the machining tunnel 40, all of which are schematically 
shown in FIG. 3, will now be discussed in more detail. One of the 
transport cars 30 is shown in more detail in FIGS. 7 and 8. More 
specifically, each transport car 30 includes a main body portion 50 which 
is securely coupled to the drive chain 32 for slidable movement along a 
lower guide track 52 (shown in FIG. 3). The support pin 34 having the 
upper stop surface 34a is securely mounted relative to the main body 
portion 50. The car 50 is also provided with a pair of cooperating 
clamping members 54 and 56 which include V-shaped clamping surfaces 54a 
and 56a respectively for securely engaging the outer surface of the 
cylindrical shell of the bearing cap assembly 10 (shown in phantom in 
FIGS. 7 and 8) during the machining operation. The clamping member 54 can 
further include a raised flat portion 56b engageable with the flat surface 
portion 20a of the mounting plate 14 to provide initial positioning of the 
bearing cap. The clamping member 54 is securely mounted relative to the 
body 50, while the clamping member 56 is mounted for selective axial 
movement toward and away from the support pin 34, as represented by 
direction arrows R. 
In FIGS. 7 and 8, the solid line position of the clamping member 56 
represents its clamped position, while the phantom position 56' represents 
its unclamped position. As will be discussed, the clamping member 56 is 
maintained in its unclamped position until the bearing cap assembly has 
been properly oriented by the positioning means 36. At that time, the 
clamping member 56 can be moved toward the clamping member 54 to securely 
grasp the bearing cap assembly. While not shown in the drawings, 
conventional means can be provided for controlling the movement of the 
clamping member 56. It should be noted that, in some instances, it may be 
desitable to fix the year clamping member 56, and mount the front clamping 
member 54 for selective axial movement. The positionng means 36 is shown 
in more detail in FIGS. 5 and 6. The positioning means includes a main 
body 60 which is supported by suitable support means (not shown) above the 
transport car and drive assembly. Prior to entering the positioning means, 
the transport car having the bearing cap assembly placed on its support 
pin must pass the limit switch unit 38. The switch unit includes a toggle 
member 62 pivotally mounted to support arm 64a and 64b attached to the 
main body 60. In the event the bearing cap is not properly placed upon the 
support pin, the limit switch 38 will trip and provide a signal which can 
be used to stop the drive assembly and prevent damage to the positioning 
means due to the misplaced part. 
The positioning means includes a hold down bar 66 similar in structure to 
the hold down bar 44 of the machining means shown in FIG. 4. The bar 66 
extends longitudinally within a downwardly facing slot 60a formed in the 
lower side of the main body portion 60. The hold down bar 66 includes a 
downwardly facing workpiece engaging surface 66a which is spring biased 
into engagement with the outer upwardly facing surface 14m of the mounting 
plate 14 of the bearing cap assembly 10 by means of a plurality of helical 
coil springs 68 mounted within spring cavities formed in the main body 
portion 60. The leading edge of the workpiece engaging surface 66a is 
provided with an inclined portion 66b for initially engaging the bearing 
cap assembly. As previously mentioned, the hold down bar 66 functions to 
maintain the inner surface 18a of the end wall 18 in positive engagement 
with the upper support surface 34a of the support pin 34. 
As previously mentioned, the positioning means 36 includes a flipper 
assembly for properly orienting the bearing cap assembly on the support 
pin 34 prior to transporting the bearing cap assembly through the 
machining tunnel. The flipper assembly includes flipper arms 72 and 74 
pivotally mounted at 72a and 74b and having outer end portions 72b and 74b 
for engaging inclined surfaces of the mounting plate. 
Each of the flipper arms 72 and 74 are secured to a shaft rotatably 
supported by the main body 60. For example, in FIG. 6, the flipper arm 72 
is secured to the lower end of a shaft 76 which is rotatably supported by 
means of bushings 76a and 76b. The upper end of the shaft 76 is provided 
with a pinion gear 78. The other flipper arm 74 is rotatably supported 
within the main body in a similar manner and, as shown in FIG. 5, is 
coupled to an upper pinion gear 80. The movement of the flipper arm 72 and 
74 is synchronized by an elongate rack member 82 having a toothed portion 
82a along one side thereof engageable with the pinion gear 78 and a tooth 
portion 82b along the opposite side engageable with the pinion gear 80. 
The rack member 82 is supported within a guide block 84 having a cover 
plate 86. The end portions of the rack member 82 are engageable with 
helical coil springs 88a and 88b. The springs 88a and 88b function to 
maintain the rack member 82 in a position such that the flipper arm 72 and 
74 are normally pivoted inwardly toward one another. 
As a transport car carries a bearing cap assembly through the positioning 
means the rear clamping member 56 of the transport car 30 is in its 
unclamped position (position 56' shown in FIGS. 7 and 8). As the bearing 
cap assembly approaches the flipper arms 72 and 74, the bearing cap 
assembly 10 is biased downwardly by the hold down bar 66. When one of the 
angled surfaces 20b or 20c of the mounting plate of the bearing cap 
assembly contacts at least one of the end portions 72b and 74b of the 
flipper arms 72 and 74, the contacted flipper arm will cause the bearing 
cap 10 to be rotated about the support pin 34 until the other one of the 
flipper arms has engaged the respective inclined surface. It should be 
noted that the downward force exerted by the hold down bar is not so great 
as to prevent rotation of the cap 10 by the initially contacted flipper 
arm. When both flipper arms have contacted their respective inclined 
surfaces, the flipper arms will simultaneously be pivoted outwardly as the 
bearing cap travels in the linear path. As soon as the flipper arms begin 
to move outwardly, the bearing cap has been properly oriented such that an 
axis X (shown in FIG. 1) extending through mounting holes 14a and 14b is 
generally perpendicular to the line of travel. At this time, the rear 
clamping member 56 can be moved inwardly to securely clamp the bearing 
assembly. 
Once the bearing cap assembly has been securely clamped, the bearing cap 
assembly is moved out of engagement with the hold down bar 66 and into the 
machining tunnel 40, shown in FIGS. 7 and 8, wherein the bearing cap 
assembly is held downwardly by means of the hold down bar 44. As the 
bearing cap is carried through the machining tunnel, the surfaces are cut 
by the spaced apart broaches 48a and 48b, while simultaneously the bearing 
cap assembly in urged into positive engagement with the support pin 34 by 
means of the hold down bar 44. 
As shown in FIG. 3, the machining tunnel comprises plurality of individual 
hold down bars 44 having a length L which is less than the distance C 
between successive bearing cap assemblies. Thus, an individual hold down 
bar 44 will only engage a single bearing cap assembly at any one time. 
While the present invention has been described for use with respect to a 
dual broaching arrangement, it will be appreciated that other types of 
machining operations could be utilized. For example, the dual broaching 
arrangement could be replaced by a pair of spaced apart milling cutters. 
While the present invention has been illustrated and described in what is 
considered to represent its preferred embodiment, it should be noted that 
the present invention can be practiced otherwise than as specifically 
illustrated and described without departing from the scope of the attached 
claims.