KEMENTERIAN PENDIDIKAN, KEBUDAYAAN,
RISET, DAN TEKNOLOGI Jalan Prof. Sudarto, S.H.
Tembalang Semarang Kode Pos 50275
UNIVERSITAS DIPONEGORO Tel. (024) 7460059, Faks. (024) 7460059
FAKULTAS TEKNIK
DEPARTEMEN TEKNIK MESIN
UJIAN AKHIR SEMESTER
PTMS 6409 ELEMEN MESIN 2
Hari/Tgl : Thursday/ 14 December 2023 (as scheduled)
Waktu : Take home test (deadlines is 1 PM, 17 December 2023)
Sifat : Open book
Pengampu : Ojo Kurdi, ST, MT, PhD
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QUESTION 1
A commercial enclosed gear drive consists of a 20° spur pinion having 16 teeth driving a 48-
tooth gear. The pinion speed is 300 rev/min, the face width 2 in, and the diametral pitch 6
teeth/in. The gears are grade 1 steel, through-hardened at 200 Brinell, made to No. 6 quality
standards, uncrowned, and are to be accurately and rigidly mounted. Assume a pinion life of
108 cycles and a reliability of 0.90. Determine the AGMA bending and contact stresses and
the corresponding factors of safety if 5 hp is to be transmitted.
[Total: 25 marks]
Question 2
A spur gearset has 17 teeth on the pinion and 51 teeth on the gear. The pressure angle is 20°
and the overload factor Ko=1. The diametral pitch is 6 teeth/in and the face width is 2 in. The
pinion speed is 1120 rev/min and its cycle life is to be 108 revolutions at a reliability R = 0.99.
The quality number is 5. The material is a through-hardened steel, grade 1, with Brinell
hardnesses of 232 core and case of both gears. For a design factor of 2, rate the gearset for
these conditions using the AGMA method
[Total: 25 marks]
Question 3
A catalog of stock bevel gears lists a power rating of 5.2 hp at 1200 rev/min pinion speed for
a straight-bevel gearset consisting of a 20-tooth pinion driving a 40-tooth gear. This gear pair
has a 20° normal pressure angle, a face width of 0.71 in, a diametral pitch of 10 teeth/in, and
is through-hardened to 300 BHN. Assume the gears are for general industrial use, are
generated to a transmission accuracy number of 5, and are uncrowned. Also assume the gears
are rated for a life of 3 x 106 revolutions with a 99 percent reliability. Given these data, what
do you think about the stated catalog power rating?
[Total: 25 marks]
1
KEMENTERIAN PENDIDIKAN, KEBUDAYAAN,
RISET, DAN TEKNOLOGI Jalan Prof. Sudarto, S.H.
Tembalang Semarang Kode Pos 50275
UNIVERSITAS DIPONEGORO Tel. (024) 7460059, Faks. (024) 7460059
FAKULTAS TEKNIK
DEPARTEMEN TEKNIK MESIN
Question 4
An uncrowned straight-bevel pinion has 22 teeth, a module of 4 mm, and a transmission
accuracy number of 5. The pinion and the gear are made of through-hardened steel, both
having core and case hardnesses of 180 Brinell. The pinion drives the 24-tooth bevel gear.
The shaft angle is 90°, the pinion speed is 1800 rev/min, the face width is 25 mm, and the
normal pressure angle is 20°. Both gears have an outboard mounting. Find the power rating
based on AGMA pitting resistance if the life goal is 109 revolutions of the pinion at 0.999
reliability.
[Total: 25 marks]
Total Mark: 100 Marks
