1. Mechanical Design of Machine Elements/Components
Gandingan
( Coupling )

2. Gandingan Tujuan: Menyambung 2 aci hujung ke hujung.
Sambungan boleh dilakukan dalam tiga keadaan kegunaan:
paksi aci-aci adalah sepaksi(collinear)
paksi aci-aci adalah bersilang(intersect)
paksi aci-aci adalah selari(parallel) tetapi tidak sepaksi
Menyambung aci mesin pemacu kepada aci mesin dipacu.
Tiga keadaan penjajaran sambungan aci

3. Jenis-jenis Gandingan
Gandingan Tegar (Rigid Couplings)~provide a connection between two perfectly aligned shafts. Frequently in use in industry ~ Steel, Copper, Paper, Petro-chemical, Food, Wastewater, Transportation and also for applications ~ Pumps; Compressors; Fans; Conveyors; anywhere motors, engines, and turbines are used
cth: gandingan bebibir(flanged coupling), clamped coupling, tapered-sleeve coupling.
Gandingan Mudah-Lentur (Flexible Coupling)
cth: rubber element Flexible Coupling, Falk Flexible Coupling, roller chain Coupling, gear type Coupling, Oldham Coupling, Universal Joints (~ Hooke’s joint and Constant velocity Universal Joints ).

4. Jenis-jenis Gandingan

5. Rigid Coupling Flexible Coupling Locks the shaft together
Alowing no relative motion between them
No provision for misalignment between them
Does not reduce shock or vibration across it from one shaft to the other
suitable for low speeds, accurately aligned shafts
Flexible Coupling
Take care of a small amount of unintentional misalignment
Allow radial, angular and axial misalignment
Slight misalignment and vibration absorbed by coupling
Provide for end float (axial movement of a shaft)

6. Flanged Rigid Coupling
Keyed Coupling
widely used
coupling halves attached to shaft ends by keys
used standard keys
Compression coupling
split double cone that does not move axially
Design consideration for flanged coupling
the torque capacity of the key or wedged friction connection with the shaft
the strength of the relatively thin web portions that are drilled to accommodate the bolts
the strength of the bolts.
For this course only item 1 and 3 will be discuss. Db
flange
bolt
key
shaft

7. tall = 0.18Su or 0.3Syp (which is lower/small)
Basic formula of shear stress analysis of bolts in coupling
where
To find the torque that can be transmited
Where td =Ssy= 0.577Sy/N or td = tall
tall = 0.18Su or 0.3Syp (which is lower/small)
Nb= number of bolts
Db= bolt circle diameter
w = 2pn/ rad/second
P = Power, kW or hp
n = rpm
Ks= service factor for machinery
To find the required bolts diameter

8. Ks = c1 + c2 Driving machines Driven machines
Table of Service Factors for Machinery
Ks = c1 + c2
Driving machines c1
Electric motors
0.5
turbomachinery
0.75
Reciprocating engines:
1.5 – 2.8
4-cylinder
6-cylinder
1 - 2
Driven machines c2
Machine tools 3
Rolling mills
1.6 -2
blowers
1.5
Textile machinery
1.6 – 2.2
Rotary pumps, compressors
Rciprocating pumps, compressors
2.2 – 3.2
Paper mills
1.8 -3
Mixing machines
Wood processing machines
2 - 3
Electric generators
1.1 – 1.3
hoists

9. Contoh: An electric motor is used to drive a blower at 600rpm
Contoh: An electric motor is used to drive a blower at 600rpm. The shaft of the motor is connected to the shaft of the blower by flange coupling. Calculate the rated power of the flanged keyed coupling assembly as shown. Given that there are 6 bolts of diameter 15mm with allowable shear strength Sall 210MPa. The bolts circle diameter is Db = 150mm. Db
Area in shear for one bolt is
Allowable force for one bolt is
Therefore the rated power is
The torque that can be transmited by six bolts which are at a 75mm distance from the central axis is

10. A rigid flange coupling used 4 bolts
A rigid flange coupling used 4 bolts. The bolts circle diameter is 125mm. If the bolt has an ultimate tensile strength of 550MPa and a yield point in tension of 345MPa, determine the bolts size if it is to transmit a torque of 2kN.m
tall = 0.18Su = 0.18(550MPa) = 99MPa
or tall = 0.3Syp= 0.3(345MPa) = 103.5MPa
Use tall= 99MPa ; T = 2kN.m ; Nb= 4
Hence from Table 8-1, use M12 bolts.