MIL-U-3963A
the other end of the joint clamped in a hori-
The application. of the load and reversal of the
zontal position. The moment of force shall not
load shall constitute one cycle. The maximum
exceed LO pound-inch. Sixteen joints shall be
rate of load and application shall not exceed
tested*
150 cycles per minute. At 10,000-cycle inter-
4.4.6 Torsional play. An 8 pound-inch
vals during the test, each specimen shall be
torque shall be applied to the joint, to obtain an
inspected for fatigue cracks in accordance with
initial reading, then the torque load shall be
the method prescribed by Type I of Specifica-
reversed and a second reading taken. The dif-
tion MIL-I-6866. After completion of 50,000
cycles in the fatigue test, each test specimen
ference between the two readings shall not
exceed the pertinent limit shown in table I.
shall be inspected for fatigue cracks in accord-
ance with Specification MIL-I-6868. The ini-
Sixteen joints shall be measured.
tial appearance of fatigue cracks shall be
4.4.7 End and side play. A 5-pound load
considered failure of the joint. After the
shall be applied alternately in either the end-
fatigue test, but prior to magnetic particle in-
wise or sidewise direction to obtain an initial
spection, the joint shall be inspected for tight-
reading, then the load shall be reversed and a
ness as specified in 4.4.5.
second reading taken. The total play is the
4.4.11 Operability test.
play recorded between the two readings. The
4.4.11.1 Phase Z. Six joints of each size
side play shall be measured in the same plane
shall be subjected to the operability test. The
as an inspection hole, then the joint rotated
operability test shall consist of a combination
through an angle of 90 degrees and measured
of operability static torque, endurance, environ-
again. The maximum allowable end play is
mental, and friction torque tests on the same
0.0024 inch. The maximum allowable side play
specimen. The joints shall be subjected to the
is 0.0056 inch. Sixteen joints shall be meas-
static torque load specified in table I for a
ured.
period of 30 seconds. After completion of the
4.4.8 Axial load. Two joints, except
static torque tests, the joints, in pairs, shall be
MS24314 joints, shall be subjected to the axial
subjected to the endurance torque specified in
tension and compression tests at zero angular-
table I at 500 rpm and 15 degrees angularity,
ity. Two flange hubs shall be subjected to the
continuously loaded in a clockwise direction for
axial tension test. The specimens shall be sub-
50,000 revolutions. After completion of the
jected to the load specified in table I for a period
initial 50,000 revolutions, the endurance test
of 30 seconds. There shall be no permanent
shall be continued for an additional 50,000
deformation of flange hubs and no excessive
revolutions, but with intermittent reversal of
tightness of universal joints after the load is
loading. The intermittent reversal of loading
removed (see 3.4.2).
shall consist of rotation with torque loading for
4.4.9 Maximum static troque. The maxi-
15 seconds followed by rotation and torque load-
mum static torque load specified in table I
ing in a counterclockwise direction for 2 min-
shall be applied to each of two joints and to
two coupling flanges. Two mating flanges shall
utes. After completion of a total of 100,000
revolutions, the bearings in the joints shall be
be used for this test. Fracture of the material
shall constitute failure.
purged with lubricant conforming to Specifica-
4.4.10 Fatigue test. At least eight joints
tion MIL-G-3278 and the joints shall be sub-
and flange hubs of each size shall be subjected
jected to the environmental tests as specified in
to the fatigue test. One-half of the test speci-
phase II.
mens shall be subjected to the test at a 5-degree
4.4.11.2 Phase II. After completion of
angularity; the remaining test specimens shall
phase I, the joints, in pairs, shall be subjected
to the following conditions in the order given:
be tested at a 20-degree angularity. Joints
shall withstand reversal of the specified torque
Step 1. Endurance test. Intermittent rever-
sal of torque loading at 1,500 rpm, 15 degrees
load for the number of cycles specified in table I.
5
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