Note: Descriptions are shown in the official language in which they were submitted.
9 8 û 7 -TC-SC
Thiæ invention relates to universal joints. More
particularly this invention is a universal joint cross
formed by joining a palr of generally cylindrical plns by
the application of heat and pressure.
5In the manufacture of universal ioints, a common
practice is to provide a cross to support the needle
bearings that permit the relative rotation of the yokes of
the universal joint. It is customary to secure one yoke to
opposite pairs of pins on the cross and to secure the other
yoke to the remaininy pair of pins on the cross.
One currently used method of making universal joint
crosses is to produce by forging or casting a cross member
and then machining and grinding the ends of the pln shafts
to form bearing surfaces for the needle bearings which are
placed over the ends of the pins. This raises problems in
the machining operations and in maintaining suitable
tolerances and efficiencies in the manufac~uring process.
The resul~ of these disadvantages is a relatively expensive
part.
20Another currently used method of making universal joint
crosses is to precision grind a long pin and two short plns
which are then assembled into a center hub~ The two small
pins ~Rually each have a forked end which encompasses the
center of the long pin in assembly. Costly equipment is
required to properly form the forked ends o~ the sma}l pins.
- Thus the making of universal joint crosses which include a
long pin and two short pins is relatively costly.
Still another method of making a universal joint cross
is described in U.S. Patent 3,110,166 patented November 12,
1963 by Mr. William ~. Shutt and entitled UUni~ersal Joint
SpiderU. In the Shutt patent the universal joint cross is
formed by resistance welding under pressure two generally
cylindrical members that have been pre-machined. ~owever,
the ends of the pins, which are to receive the needle
bearings must still be ground and polished after the cross
has been formed. This takes additional equipment and
fixtures and time which would not be required if the steps
in the Sbutt process of grinding and polishing the bearing
-- 2
surfaces of the pins after they are welded together
were eliminated.
This invention is a new universal joint cross
and a new rnethod of making a universal joint cross.
The cross is complete and ready for use after the
pins have been formed into the cross. There is no
need for the final steps of grinding or polishing
or any other treatment of the bearing ends of the
pins.
Briefly described, the new universal joint cross
comprises a first generally cylindrical hardened an
ground pin and a second generally cylindrical hardened
and ground pin forming bearing pins. The pins are
disposed transversely to each other and have their
axes in a common plane. The cross is formed by welding
the two pins under pressure while controlling the
lengths of the welds on the pins to provide bearing
surfaces on the ends of the pins with an undisturbed
rnetallurgical structure.
A plastic hub is molded around the welded center
of the universal joint cross to create thrust surfaces.
My new method of making the universal joint cross
comprises the steps of hardening and grinding a pair
of pins. One pin is then positioned on a first elec-
trode with the hardened and ground pin ends extending
beyond the outer periphery of the first electrode
and into support means separate from the first elec-
trode. The second pin is positioned in a second elec-
trode with the hardened and ground pin ends extend-
ing beyond the ou-ter periphery of the second electrode
and into suppart means separate from the second elec-
trode and with the pin axes disposed transversely
to each other. The electrodes and the support means
are pushed together and direct current pulses are
periodically applied across the electrodes at a con-
- 2a -
trolled pulse intensity and controlled pulse duration
whereby to control the lengths of the pins which are
heated to cause only the central portion of the
material on the pins to melt to join the pins leaving
the pin ends hardened and ground.
The invention as well as its many advantages
will be further understood from the following detailed
description and drawings in which:
Fig. 1 is a side view of a preferred embodiment
of cross in accordance with this invention;
Fig. 2 is a front view taken along lines 2-2
of Fig. 1 and in the direction of the arrows;
Fig. 3 is a back view taken along lines 3-3 of
Fig. 1 and in the direction of the arrows;
9807 -TC-SC
....
. .
Fig. 4 is a side view of part of a pref erred embodiment -- -
of die and welding machine assembly used to make the new ~.
universal j oint cross with parts broken away and in section , .
to illustrate the position of the various parts;
FigO 5 is a view ~aken along lines 5--5 of Fig. 4 and --
in the direction o the arrows; and ----
Fig. 6 is a f ront view of a completed hub and cross c-
a ssembly ~ --
In the various f igures like parts are referred to by --
like numbers.
.-..
Referring to the drawings and more particularly to
Figs. 1 through 3 the new universal joint crvss has a first
generally cylindrical hardened and ground pin 10 and a
second generally cylindrical hardened and ground pin 12.
These pins are shown after they are joined together into a
universal joint cross by the application o~ controlled
amounts of electrical current to join the pins together by
- controlled heat and high pressure. ~he ends 14 and 16 Of
pin 10, and the ends 18 and 20 of pin 12 serve as ~earing
surfaces for the annulus of nee~les in needle bearings, not
shown, which are commonly placed over the ends of the pins
10 and 12. The enlarsement 22 is formed during the welding
operation and represen~s material that is displaced during
. -
the welding operation.
In forming the new universal joint cross the pins 10
and 12 are first hardened and ground. Before being joined
together to form the cross, the pins lQ and 12 have the same -
.
diameter throughout their length. It has been found that if
the center areas are reduced the resulting cross is too weak
3~ to be useful in high load applications.
The pins are positioned with one pin above the other
pin with their axes disposed transversely to each other.
The pin~ are joined at their respective centers by the
precise application of heat and pressure while controlling
the distance from the centers o~ the pins the pin~ are
heated~ ~he resulting universal joint cross then has the
shape shown in Figs. 1 through 3~ .
Fig. 4 and Flg. 5 show a portion of the die or fixture
~2~ ~3
4 .-
_ _
-
used to perform the welding operation. Tne die includes abottom assembly having a copper electrode 24 with a pedestal
26. The pedestal 26 inc~udes a central groove 28 for
suppor~ing one of the pins. The semi circular grooves 30
and 32 adjacent each side of ~he pin supporting groove 28
are provided in the copper pedestal 26 to provide a-place
for the molded metal to go before the metal solid1fies into
the enlargement 22 of Figs. 1 through 3.
An annular steel disk 34 (see Fig. 5~ having a central
bore 36 rests on the annular shoulder 38 of the copper
electrode 24. The pedestal 26 of the electrode 24 extends
partially through the bore 36 of annular disk 34. The
diameter of the bore 36 is greater than the diameter of the
pedestal 26 thus providing an annular space 40.
Four perpendicular semi-circular grooves 42, 44, 46,
and 48 (see Fig. 5) extend fr~m the bore 36 of annular disk
3~ to the perimeter of the annular disk 34. Semi-circular
grooves 42 and 46 are in line with the pin supporting groove
28 of the pedestal 26; semi-circular grooves 44 and 48 are
perpendicular to the pin supportiny groove 28r The copper
electrode pedestal 26 is also provided with a short semi-
circular groove 50 in line with groove 44 of the annular
disk 34 and a short semi-circular groo~-e 52 in line with
.....
groove 48 on the annular disk 34. ~
The top assembly of the dle or fixture used to weld the ...
pins together to form the universal joint cross, as ~een in .-.
Fig. 4 includes a top copper electrode 60 with a centrally ..
located pedestal 62. A steel annular disk 64 with a central .. -
bore 66 fits over the copper pedestal 62. The diameter of ...
30 the bore 66 is larger than the diameter of the pedestal 62 -.
thu~ providing an annular space 68. Semi-circular grooves
70 and 72 on annular disk 64 register with semi-circular ~-
grooves 44 and 48, respectively, on annular disk 34. .~
~nnular disk 64 i8 provided with additional grooves ~not ~-
1 35 shown) which register with the grooves 42 and 46 (see Fi~. -
: 5) on the annular disk 34.
The pedestal 62 of upper copper electrode 60 is also
provided with a curved pin support, and two adjacent
.....
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semi~circular grooves all of which exrend perpendicularly to --.
the pin support 28 and two adjacent grooves 30 and 32 on
pedestal 26 of ~he lower copper electrode 24. In addition, F
the upper copper electrode pe~estal 62 is provided with -~
5 short semi-circular grooves (not shown) which are in line
with semi-circuiar grooves (not shown) extending from the ~--
bore 66 of the upper annular steel disk 64 to the outer
perimeter of the upper annular steel disk 64 and are .~-
registered with the annular grooves 42 and 46 of the lower
10 annular disk 34. --~
. . . _ . .
To practice my new method of making a universal joint
cross, a pair of pins like pins 10 and 12 are hardened and
ground. One pin is placed on the groove 28 of the pedestal
26 of the lower copper electrode 24. The other pin is
15 positioned in the center perpendicular groove ~not shown) on
the pedestal 62 of the upper copper electrodes 60 with the
two pins positioned with their axes disposed transversely to
- each other.
~- ~ Referring to Fig. 4 note that the pin 12 is positioned
20 so that the hardened and ground pin ends 18 and 20 extend
beyond the outer periphery of the pedestals 26 and 62 and
into the grooYes of the annular disks 38 and 64. Similarly,
the hardened and ground ends 14 and lfi o~ pin 10 extend
beyond the outer periphery of the pedestals 26 and 62 and
25 into grooves of the annular disks 38 and 64. The upper and
lower assemblies are then pushed together so that the pins
are joined at their respective centers by the precise
application of heat and pressure. The heat is applied by
periodically pulsing direct current pulses across the upper
30 and lower copper electrodes.
The proper co~trol of the electrical pulses across the
electrodes and the locating of the pins so that the hardened
pin ends extend into the grooves contained in annular disks
38 and 64 permits one to control the length of the weld from
35 the center. ~he lengths of the pins 10 and 12 which is
heated is controlled so that only the central portion of the
material on the pins is melted to provide the enlargement
22. The intensity and duration of the electriral pulses and
. . .
!l
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, . .
the location of the pins is such that the hardened pin ends,
18 and 20 on pin 12/ and 14 and 15 on pin 10 are not heated
duriny the operation. Tnus the portions 18 and 20 on pin 12 r'
and 14 and 16 on pin lO remain hardened so that the --
metallurgical structure of the hardened and ground pins at
those points are not disturbed. This is very important
because the hardened pin ends are the parts which support r''-'~
_._
the needle bearings. r'''''
After the universal joint cross has been completed a -_
lO jacket or hub of plastic 80 is molded around the welded ,-~
cen~er of the universal joint cross to create thrust sur-
faces for the needle bearings which are to be placed over
the ends 14 and 16 of pin lO and the ends 18 and 20 of pin
12. The plastic hub 80 is generally in the shape of a cubic
center portion 82 having the annular protuberances 84, 86,
88, and 90 extending from the four sides of the center
cubular por~ion 82 through which pins lO and 12 extend.
~ Annular protuberances 88 and 84 extend longitudinally
partially along the pin lO. Annular protuberances 86 and 90
e~tend partially alon~ pin 12. The extension of each of the
annular protuberances 84, 86, 88 and 90 is such that the
welded center port'ion of the universal ~oint cross is
covered by the plastic hub 80 leaving exposed the hardened
pin ends 14, 16, 18, and 20. The needle bearings (not
shown) which are placed over the hardened ends of the plns
lO and 12 thus have the needle rollers in the needle roller
bearings in contact with the hardened portions 14, 16, 18
and 20. Contact of needle rollers with hardened portions is
.-
necessary for the proper operation of the universal joint.
The annular extreme ends 92 and 94 of annLllar
protrusions 88 and 84, respectively, are perpendicular to
the axis of the pin lO and thus provide thrust surfaces for
the needle roller bearings (not shown) which are later
placed on ~he ends 14 and 16 of pin lO. The annular ex~reme
ends 96 and 98 of annular protrusions 86 and 90, respec-
tively, of the hub 80 extend perpendicularly to the axis of
pin 12 and serve as thrust surfaces for the needle roller
....
bearings (not shown) which are to be placed over the -"
hardened ends 18 and 20 of pin 12. --
._
