Poona Couplings

Flexible Coupling ( RB )

 
POONA COUPLINGS have been leaders in the design and manufacture of flexible couplings for over 25 years. with the following capabilities:

 

Flexible Couplings ( RB )
General purpose, cost effective range which is manufactured
in C.I. & S.G. iron Torques up to 41 kNm.
Rating: 0.12 HP/RPM to 5.5 HP/RPM
Flexible Couplings ( RB )
 
 
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Flexible Couplings ( RB )
1. Approved to ISO 9001-2008 Certificate & API
2. Total quality system
3. Latest CAD technology
4. Torsional vibration analysis
5. Transient and finite element analysis
 
General purpose, cost effective range which is manufactured in C.I. & S.G. iron torques up to 41 kNm.
 
THE STANDARD RANGE COMPRISES
1. Shaft to shaft
2. Shaft to shaft with increasing shaft engagement
3. Flywheel to shaft
4. Flywheel to shaft with increased shaft engagement
 
APPLICATION
1. Generator sets
2. Pump sets
3. Compressors
4. Wind turbines
5. Metal manufacture
6. Bulk handling
7. Pulp and paper industry
8. General purpose heavy duty industrial applications
 
FEATURES BENEFITS
1. Intrinsically fail safe
1. Ensuring continuous operation of the driveline in the unlikely event of rubber damage
2. Control of resonant torsional vibration
2. Achieving low vibratory loads in the driveline components by selection of optimum stiffness characteristics.
3. Maintenance free
3. With no lubrication or adjustment required resulting in low running costs
4. Severe shock load protection
4. Avoiding failure of the driveline under short circuit and other transient conditions.
5. Misalignment capability
5. Allows axial and radial misalignment between the driving and driven machines.
6. Zero backlash
6. Eliminating torque amplifications through precompression of rubber elements.
7. Low cost
7. The RB Coupling gives the lowest lifetime cost.
 
Construction details
1. Cast iron to BS 17 grade
2. Spheroidal graphite to BS 2789 Grade 420/12.
3. Separate rubber elements with a choice of grade and hardness with SM70 shore hardness being the standard.
4. Rubber elements which are totally enclosed and loaded in compression.
Flexible Couplings
 
Flexible Couplings
FEATURES BENEFITS
1. Can accommodate a wide range of shaft diameters
1. Allows the optimum coupling to be selected.
2. Easy disconnection of the outer member and driving flange
2. Allows the driving and machines to be disconnected
3. Coupling available with limited end float.
3. Provides axial location for armatures with axial float.
Dimensions, Weight, Inertia and Alignment
 
RB Shaft to shaft With Increased Shaft Engagement
Right half / Flex half
Flexible Couplings
FEATURES BENEFITS
1. Long Boss Inner Member
1. Allows small diameter long length shafts to be used
2. Reduces key stress
3. Allows increased distances between shaft ends
4. Full shaft engagement avoids the need for spacer collars
Dimensions, Weight, Inertia and Alignment
 
RB Standard SAE Flywheel to shaft (0.24 to 1.15)
Flexible Couplings
FEATURES BENEFITS
1. Wide range of adaptor plates
1. Allows the coupling to be adapted to suit most engine flywheels
2. Choice of rubber compound and hardness
2. Allows control of the torsional vibration system
3. Short axial length
3. Allows the coupling to fit in bell housed applications
Dimensions, Weight, Inertia and Alignment
RB Standard SAE Flywheel to shaft
Flexible Couplings
Dimensions, Weight, Inertia and Alignment
 
RB Standard SAE Flywheel to shaft With Increased shaft Engagement
Flexible Couplings
FEATURES BENEFITS
1. Long Boss Inner Member
1. Allows small diameter long length shafts to be used
2. Reduces key stress
3. Allows increased distances between shaft end and flywheel
4. Full shaft engagement avoids the need for spacer collars
 
RB Standard SAE Flywheel to shaft With Increased shaft Engagement
Flexible Couplings
INDUSTRIAL DRIVES
 

For industrial electrical Motor Applications refer to the "Selection Procedures " and base selection on Tkmax with the appropriate services factors.
The services factors used in the " Selection Procedures " are based upon 40 years of Holset's experience of drives and their shock frequency / amplitude. The stated Tkmax quoted should not exceed by design , without reference to PCPL. )
Care needs to be taken in the design of couplings with shaft brakes to ensure the coupling torques are not increased by severe deceleration.

2.0 STIFFNESS PROPERTIES--
The RB Coupling retains fully flexible under torque conditions. The RB Series is a non-bonded type operating with the Rubber-in-Compression principle.

2.1 AXIAL STIFFNESS-
When subject to misalignment forces in the axial direction , the coupling will have an axial resistance which gradually reduces due to the effect of vibratory torques.
Given sufficient axial force as shown in the catalogue, the coupling will slip to its new position immediately.

2.2 RADIAL STIFFNESS---
The radial stiffness of the coupling is torque dependent, and is as shown in the Technical Data.

2.3 TORSIONAL STIFFNESS--
The torsional stiffness of the coupling is dependent upon applied torque ( see Technical Data ) and temperature.
2.4 -- PREDICTION OF THE SYSTEM TORSIONAL VIBRATION CHARACTERISTICS-----
An adequate prediction of the system torsional vibration characteristics can be made by the following method.
2.4.1-- Use the torsional stiffness as published in the catalogue which is based upon data measured at 30 C ambient temperature.
2.4.2- Repeat the calculation made as 2.4.1 but using the maximum
temperature correction factor St100 and M100 for the rubber selected for both torsional stiffness and dynamic magnifier from the table.
2.4.3 Review the calculations 2.4.1 and 2.4.2 and if the speed range is clear of criticals which do not exceed the allowable heat dissipation value as published in the catalogue, the coupling is then considered suitable for the application with respect to the torsional vibration characteristics. If there is critical in the speed range the actual temperature of the coupling will need to be calculated at this speed.

2.5 PREDICTION OF THE ACTUAL COUPLING TEMPERATURE AND TORSIONAL STIFFNESS---

2.5.1 Use the torsinal stiffness as published in the catalogue, which is based upon data measured at 30o C and the dynamic magnifier at 30o C ( M30 )
2.5.2-- Compare the synthesis value of the calculated heat load in the coupling ( P x ) at the speed of interest to the " Allowable Heat Dissipation " ( P kw )
The coupling tmperature rise
C + Temp = ( Px / P kw ) X 70
The coupling temperature = o
o = Temp + ambient Temp.

2.5.3- Calculate the temperature correction factor St from 2.6 ( If coupling temperature > 100 C, then use S )
Calculate the dynamic magnifier as per 2.7. Repeat the calculation with the new value of coupling stiffness and dynamic magnifier.

2.5.4-- Calculate the coupling temperature as per 2.5, Repeat calculation
until the coupling temperature agrees with the corrction factors for torsional stiffness and dynamic magnifier used in the calculation.

   
RB - 0.12 SP ASSY RB - 0.2 SAE 7.5 B&K ASSY DRG WITH KPLATE
RB - 0.24 SAE 10 WITH LONG BOSS - B&K - ASSY DRG RB - 0.24 SAE 10 WITH SPLINES - ASSY
   
   
RB - 0.24 SP ASSY RB - 0.24 STD SAE 10 ASSY DRG
   
RB - 0.37 SP ASSY WITH SPACER & LB IM RB - 0.73 STD 11.5 - ASSY DRG
   
RB - 0.73 STD.SAE 14 - B&K - ASSY DRG RB - 3.86 SAE 18 BK - ASSY DRG -WITH SILICONE RUBBER
   
RB - 3.86 SHAFT TO SHAFT - VERTICAL ASSY DRG WITH SPACER RB - 3.86 STD SAE 18 - B&K - ASSY DRG
   
RB - 3.86 WITH STUB SHAFT - ASSY DRG WITH B&K RB - 5.5 SAE 18 WITH Si-70 - ASSY DRG
   
RB - 5.5 SA 21 - B&K - ASSY DRG  
 
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