Transcript Belt Seminar - CR Products website

Drive Design Seminar
Product Description
Materials
Cost Drivers
General Drive Design
Additional Considerations
Product
Product Description
• General Information
• Standard Product
• MTO Product
Product - General
Two Major Belt Categories
• V-Belt works on the principle of
the wedge and relies on tension
to create friction on the sidewall
of the sheave to transmit power
• Synchronous or timing belt
relies on accurate and smooth
meshing of the teeth on the belt
with the grooves of the sprocket
Product - General
Two Major Types of V-Belts
• Wrapped Molded which has
a fabric cover and is molded
into a V shape
• Raw Edge which is cured
and then cut into a V shape
Product - General
Industry Standards
Standards are determined by the following
manufacturing associations:
• RMA – Rubber Manufacturers Association
• MPTA – Mechanical Power Transmission Association
• ISO – International Standard Organization
• SAE – Society of Automotive Engineers
• API – American Petroleum Institute
• ASAE – American Society of Agricultural Engineers
• Government Standards
Product - Standard
Standard Belts
•
•
•
•
•
•
•
•
Classical (Multiple)
Single (FHP)
Narrow (Wedge)
Double-V (Hexagonal)
Joined (Banded)
V-Ribbed
Variable Speed
Synchronous (Timing)
Product - Standard
Classical V-Belts
Reference ASAE S211.5 & RMA Standard IP-20
Nominal Cross-Section Dimensions (inches)
Belt Reference Nomenclature
Part Number:
A63
Belt Type:
A
Outside Length (O.L.): 65.3”
Part Number + 2.3”= Belt O.L.
Cross
Section
Top
Width
Th.
Angle
(degrees)
O.L.
Add-ons
A/AX
0.500
0.310
40/38
2.3
B/BX
0.660
0.410
40/38
2.8
C/CX
0.880
0.530
40/38
4.2
Note(s): Typical cross section designation
for Aggie/LG Belts adds ‘H’ prefix.
For example: HA, HB, etc.
D/DX
1.250
0.750
40/38
5.2
For metric designations, refer to
appropriate Industry Standard.
Wrapped Molded
(A, B, C, & D Sections)
Th
Raw Edge – Cog
(AX, BX, CX & DX Sections)
Angle
Angle
TW
TW
Th
Product - Standard
Single (FHP) V-Belts
Reference RMA Standard IP-23
Belt Reference Nomenclature
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
2L
0.250
0.160
40/36
3L
0.380
0.220
40/36
4L
0.500
0.310
40/36
5L
0.660
0.380
40/36
Wrapped Molded
Angle
TW
Th
Part Number:
4L500
Belt Type:
4L
Outside Length (O.L.): 50.0
Part Number=
Belt O.L.
Note(s): For metric designations, refer
to appropriate Industry Standard.
Raw Edge Laminated
Product - Standard
Narrow V-Belts
Reference ASAE S211.5 & RMA Standard IP-22
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
3V/3VX
0.380
0.310
40/36
5V/5VX
0.620
0.530
40/36
8V
1.000
0.910
40
Wrapped Molded
(3V, 5V, & 8V Sections)
Raw Edge Cog
(3VX & 5VX)
Belt Reference Nomenclature
Part Number:
5V630
Belt Type:
5V
Outside Length (O.L.): 63.0”
Part Number =
Belt O.L.
Note(s): Typical cross section designation
for Aggie/LG Belts adds an ‘H’ prefix.
For example: H3V, H5V, etc.
For metric designations, refer to
appropriate Industry Standard.
Product - Standard
Double-V (Hexagonal) V-Belts
Reference ASAE S211.5 & RMA Standard IP-21
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
O.L.
Add-ons
AA
0.500
0.410
40
3.4
BB
0.660
0.530
40
4.6
CC
0.880
0.690
40
6.4
Cross Sections (AA, BB, & CC Sections)
Belt Reference Nomenclature
Part Number:
AA60
Belt Type:
AA
Outside Length (O.L.): 63.4
Part Number =
Belt O.L.
Note(s): Typical cross section designation
for Aggie/LG Belts adds ‘H’ prefix.
For example: HAA, HBB, etc.
For metric designations, refer to
appropriate Industry Standard.
Product - Standard
Joined (Banded) V-Belts
Reference ASAE S211.5 & RMA Standards IP-20 & IP-22
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
Sg
(in.)
O.L.
Add-ons
B/BX
0.660
0.500
40/38
0.750
4.0
C/CX
0.880
0.660
40/38
1.000
5.3
D/DX
1.250
0.840
40/38
1.438
6.3
3V/3VX
0.380
0.380
40/38
0.406
1.1
5V/5VX
0.620
0.620
40/38
0.688
1.1
WRAPPED MOLDED
(RB, RC, RD, R3V & R5V)
Angle
TW
Belt Reference Nomenclature
Part Number:
RB103-3
Belt Type:
B
Number of ribs/band:
3
Outside Length (O.L.): 107.0
Part Number + 4.0”= Belt O.L.
Note(s): Typical cross section designation for
Aggie/L&G Belts adds ‘H’ prefix.
For example: RHB, R3V, etc.
- For metric designations, refer to appropriate
Industry Standard.
RAW EDGE – COG
(RBX, RCX, RDX, R3VX & R5VX)
Angle
Th
TW
Th
Product - Standard
V-Ribbed Belts
Reference ASAE S211.5 & RMA Standard IP-26
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
Sg
(in.)
O.L.
Add-ons
J
0.092
0.160
40
0.092
0.5
K
0.140
0.240
40
0.140
See Notes
L
0.185
0.380
40
0.185
1.0
M
0.370
O.660
40
0.370
2.0
Cross Sections (J, K, L, & M Sections)
Angle
TW
Th
Belt Reference Nomenclature
Part Number:
400J6
Belt Type:
J
Number of ribs/band:
6
Outside Length (O.L.): 40.5”
Part Number + 0.5” = Belt O.L.
Note(s): For metric designations, refer
to appropriate Industry Standard.
The ‘K’ Section is primarily an MTO
item and belt section parameters are
determined by application.
Product - Standard
Variable Speed V-Belts
Reference RMA Standard IP-25
Nominal Cross-Section Dimensions (inches)
Cross
Section
Top
Width
Th.
Angle
(degrees)
O.L.
Add-ons
1422V
0.880
0.310
22
0.60
1922V
1.190
0.380
22
0.60
2322V
1.440
0.440
22
0.70
1926V
1.190
0.440
26
0.80
2926V
1.810
0.500
26
0.80
3226V
2.000
0.530
26
0.80
2530V
1.560
0.590
30
1.10
3230V
2.000
0.620
30
1.10
4430V
2.750
0.690
30
1.10
4036V
2.500
0.690
36
1.10
4436V
2.750
0.720
36
1.10
4836V
3.000
0.750
36
1.10
Belt Reference Nomenclature
Part Number:
3226V603
Belt Top Width in 1/16”:
32
Intended Pulley Angle:
26
Outside Length (O.L.):
61.1”
Part Number + 0.80”= Belt O.L.
Raw Edge Cog Belts
Angle
TW
Th
Note(s): Aggie counterparts to
these sections are
termed Adjustable Speed Belts
and are listed in the SAE S211.5
Standard.
- For metric designations, refer
to appropriate Industry
Standard.
Product - Standard
Synchronous (Straight Sided) Belts
Reference RMA Standards IP-24
Nominal Cross-Section Dimensions (inches)
Pitch
Pb
Hs
Th.
MXL
0.080
0.045
0.020
XL
0.200
0.090
0.050
L
0.375
0.140
0.075
H
0.500
0.160
0.090
XH
0.875
0.440
0.250
XXH
1.250
0.620
0.375
DXL
0.200
0.120
0.050
DL
0.375
0.180
0.075
DH
0.500
0.234
0.090
Cross
Section
Hd
Th.
Ht
Th.
Belt Reference Nomenclature
Part Number:
770XL025
Belt Type:
XL
Width (1/100”):
0.25”
Pitch Length (nearest 1/10”): 77.0”
Part Number = Pitch Length *10
Notes: For metric information
refer to appropriate Industry Standard.
Synchronous Single Sided (MXL, XL, L, H, XH & XXH Sections)
Synchronous Double Sided (DXL, DH & DXH Sections)
Product - Standard
Synchronous (Curvilinear Toothed) Belts
Reference RMA Standard IP-27
Nominal Cross-Section Dimensions (mm)
Pitch
Pb
Hs
Th.
8M
8.0
5.4
3.2
14M
14.0
9.7
6.0
Cross
Section
Hd
Th.
Ht
Th.
Belt Reference Nomenclature
Part Number:
600-8M-20
Belt Type:
8M
Width (mm):
20
Pitch Length (mm):
600
Part Number = Pitch Length
Curvilinear Single Sided (8M & 14M Sections)
D8M
8.0
7.8
3.2
D14M
14.0
14.5
6.0
Curvilinear Double Sided (D8M & D14M Sections)
Product - MTO
Made-to-Order (MTO)
Key: Application-Specific Design
Design machine around standard belt???
or…
Design MTO belt around machine???
Product - MTO
Modifications
The following may be changed to create
a Made-to-Order (MTO) Belt
• Length
• Construction
• Materials
• Cross-Section
Product - MTO
Length Modifications
• Non-Standard Lengths (std = 1” increments)
• Application-Specific Tolerances
Product - MTO
Construction Modifications
• Raw-Edge vs. Wrapped
• Cogged versus Plain RE
• Fabric Plies
• Cord Position
Product - MTO
Material Modifications
• Rubber – abrasion resistance, heat
resistance, oil resistance, fiber loading,
flex resistance
• Cord – shock loading, synchronous
tracking, belt stretch
• Fabric – clutching requirements, static
conductivity
Product - MTO
Cross Section Modifications
• Width
• Thickness
• Angle
Product Description
Materials
Cost Drivers
General Drive Design
Additional Considerations
Materials
Three Basic Materials
• Rubber
• Cord
• Fabric
Materials - Rubber
Rubber: General Information
• Used in all facets of our life
• Over 80 pounds in every car
• Natural rubber was primary elastomer prior to WWII
• Synthetic rubber (SBR) was introduced in the late
1940’s
• Chloroprene was introduced in the late 1950’s
• Today we use rubber compounds – blending natural
and synthetic to achieve optimal properties
Materials - Rubber
Rubber Compound Formulation
•
•
•
•
Improved processing characteristics
Improved strength and/or hardness
Protection from working environment
Enhance vulcanizing (curing)
Materials - Rubber
Typical Rubber Formulation
• Elastomer (SBR, Neop, NBR, etc.)
 50% - 60%
• Fillers (Carbon Black, Fiber, etc.)
 30% - 40%
• Vulcanizers, Cure Agents, Accelerators,
Retarders, Processing Aids
 5% - 10%
Materials - Rubber
Engineering Properties
RUBBER
TYPE
TEMP
Amb (F)
PHYSICAL CHARACTERISTICS
OIL/CHEM
FLEX
HYSTERSIS
ABRASION
OZONE
SBR
-40/+160
Fair/Poor
Good
Good
Good
Fair
4
SBR-F
-40/+160
Fair/Poor
Fair
Fair
Exc
Fair
3
CR
-35/+190
Good
Exc
Exc
Good
Good
2
CR-F
-35/+190
Good
Fair
Good
Exc
Good
1
NBR
-45/+220
Exc
Fair
Good
Good
Poor
4
BR
-45/+180
Fair/Poor
Good
Exc
Exc
Fair
4
HSN
-30/+230
Exc
Exc
Good
Good
Exc
3
PDf
LEGEND:
SBR:
Styrene-Butadiene
SBR-F:
Styrene-Butadiene
Fiber Reinforced
CR:
Neoprene Rubber
CR-F:
Neoprene Rubber
- Fiber Reinforced
NBR:
Nitrile Rubber
BR:
Polybutadiene Rubber
HSN:
Highly Saturated
Nitrile
PDf:
Power Density Factor
Ability/strength of
rubber to support
power transmission.
1 being the best.
Materials - Cord
Cord: General Information
• Cotton – used extensively in 1940’s & 1950’s
• Rayon – popular in the 1950’s & 1960’s
• Polyester – introduced in the 1950’s, dominant belt tensile
member today
• Steel – introduced in the late 1950’s
• Fiberglass - introduced in the late 1950’s, popular in synchronous
belts
• Nomex – introduced in the 1960’s
• Aramid (Kevlar) – introduced in the 1970’s, popular in lawn and
grounds applications
Materials - Cord
Engineering Properties of Various Fibers
Material
Specific Gravity
Tensile Strength
(psi)
Rayon
1.52
115,000
Nylon
1.14
140,000
Polyester
1.38
160,000
Fiberglass
2.54
195,000 / 310,000
Steel
7.85
340,000
1.39 / 1.45
400,000 / 495,000
Aramid
Materials - Cord
R&D Efforts
Focused on Treating and
Construction
• Developing proper cord twist
• Temperature
• Tension
• Time
Materials - Cord
Most Commonly Used
• Polyester
• Fiberglass
• Aramid
Materials - Cord
Polyester
• Moderate Cost
• Good Tensile Strength with Moderate Stretch
• Excellent Flex Properties
• Shrinkage when Subjected to Heat
• Excellent Shock Absorption
Materials - Cord
Fiberglass
• Moderate Cost
• High Tensile Strength with No Stretch
• No Shrinkage
• Poor Flex Qualities
• Low Tolerance for Misalignment
• Low Shock Absorption Qualities
Materials - Cord
Aramid
• High Cost
• High Tensile Strength with Minimal Stretch
• No Shrinkage
• Good Flex Qualities
• Some Tolerance for Misalignment
Materials - Cord
Engineering Properties
CORD TYPE
BELT
SECTION
ELONG. %
*
TENSILE
(MIN)
SHOCK
FLEX
Polyester - A
Sm PV
3.0
52
Excellent
Exc
Polyester - B
Sm WM
3.0
145
Excellent
Exc
Polyester - C
Sm RE
2.0
145
Good
Good
Polyester - D
Lg WM
3.0
210
Excellent
Exc
Polyester - E
Lg RE
2.5
210
Good
Good
Polyester - F
X-Lg RE/WM
2.5
385
Good
Good
Aramid - A
Sm PV
1.5
95
Good
Good
Aramid - B
Sm RE/WM
1.0
325
Good
Good
Aramid - C
Lg RE/WM
1.0
495
Good
Good
Fiberglass - A
Sm RE/WM
1.0
150
Poor
Poor
Fiberglass - B
Lg RE/WM
1.0
220
Poor
Poor
Fiberglass - C
Sync Belts
0.5
175
Good
Good
Fiberglass - K
Sync Belts
0.5
230
Good
Good
*Elongation % is an
approximation of belt
elongation over its
normal life under normal
load and operating
conditions.
NOTE: Common trade
names for Aramid are
Kevlar (Dupont) and
Twaron (Teijin/Twaron)
Legend:
WM = Wrapped-Molded
RE = Raw Edge belts
PV = V-Ribbed Belts
Materials - Fabric
Fabric: General Information
Typically Square, Tubular Woven or Angle Induced
• Square Woven can be produced on high speed looms
– Highest bias angle = 90 degrees
• Tubular Woven is produced as a tube on slow speed looms
– Bias angle can be 110 degrees
– High bias angle = improved flexibility
• Angle Induced is produced on high speed looms as a square
woven fabric and the angle is shifted during treatment
– Bias angle can be 110 degrees
– High bias angle = improved flexibility
Materials - Fabric
Polyester/Cotton Blends
• Balance of Cost and Performance
• Easy to Process
• Good Bonding Qualities
• Good Abrasion Resistance
• Used to Develop Static Conductivity
Materials - Fabric
Nylon
• Excellent Abrasion Resistance
• Higher Elasticity
• Primarily Used in Synchronous Belts
• Very Difficult to Work With
Materials - Fabric
Fabric Treating
Single-Sided Coating (Bareback)
• Low coefficient of friction for clutching drives
Double-Sided Coating
• Used for wrapping of molded belts
• Used for crack barrier in wrapped-molded belts
• Used for laminates in raw edge belts
Materials - Fabric
Methods of Treating
• Frictioning
• Dipping / Spreading
• Skimming
Product Description
Materials
Cost Drivers
General Drive Design
Additional Considerations
Cost Drivers
Cost Drivers
•
•
•
•
Construction
Materials
Secondary Operations
Tooling
Cost Drivers - Construction
Wrapped-Molded V-Belt
• 2 Ply vs. 1 Ply Wrap
• Cord Types
• Rubber Core
• Profile Differences
Cost Drivers - Construction
Raw Edge V-Belt
• Multiple Layers of Fabric
Laminate
• Cord Types
• Rubber
• Profile Differences
• Cogged vs. Non-Cogged
Cost Drivers - Materials
Cord
Rubber
Fabric
Material
Polyester
Fiberglass
Aramid
Relative Cost
1.00
1.05
1.15/1.25
SBR-G
SBR-F
Neoprene G
Neoprene F
1.00
1.10
1.20
1.10/1.25
Standard
Dry Surface
Extra Dry Surface
1.00
1.20
1.60
Note: Relative cost is based on total belt cost
Cost
Drivers
Cost Drivers – Secondary
Operations
Secondary Operations
•
•
•
•
Trimming
Printing
Packaging
Measuring
Cost Drivers – Tooling
Tooling
• Raw Edge - drums range from $2000 to
$8000
• Wrapped-Molded - ring molds range from
$2000 to $20,000
• Synchronous - molds range from $2000 to
$18,000
Product Description
Materials
Cost Drivers
General Drive Design
Additional Considerations
Drive Design
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design - Theory
Power Transmission and V-Belt Theory
The function of a belt is to
simply transfer rotation from the
powered pulley to one or more
driven pulleys. The belt must be
designed and manufactured to
transfer this torque efficiently
and reliably.
Drive Design - Theory
Means of Power Transmission
•
•
•
•
•
•
V-Belts
Chains
Gears
Synchronous Belts
Hydraulics
Electronics
Drive Design - Theory
V-Belt Characteristics
• Less expensive than other forms of power transmission
• Start, stop and run smoothly
• Operate noiselessly and without lubrication
• Absorb objectionable and harmful vibrations
• Clean and require minimum maintenance
• Rugged and long lasting
• Provide a wide selection of speed ranges
• Cover an extremely wide horsepower range
• Easy to install and simple to replace
• Relatively unaffected by moisture, abrasive dusts,
or extreme variations in temperature
Drive Design - Theory
V-Belt Principle of Wedging
Drive Design - Theory
V-Belt Drive Terminology
Drive
Design
Drive Design
- Tension
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design - Tension
2 Pulley Drive at Rest
DRIVER
Ts
DRIVEN
Ts
Static
Condition
Ts
Ts
Ts = Static Strand Tension
2 Pulley Drive in Motion
DRIVER
T1
Q
DRIVEN
T1
Dynamic Condition
T2
T2
T1 > T2
T1 = Tight Side Tension
T2 = Slack Side Tension
Drive Design - Tension
Effective Pull
Effective pull can be calculated by:
EP = T1 – T2 = 24 Q (LBS.)
D
Where Q = Torque (FT-LBS) at the sheave
D = Pitch diameter of sheave (Inches)
Effective pull can also be calculated using the horsepower (HP) and
belt speed (S) of the drive as follows:
EP = HP x 33000 (LBS.)
S
This difference in belt tensions also introduces a term known as tension ratio (R):
Tension Ratio (R) = T1
T2
Drive Design - Tension
Strand Tension
The following formula is used when calculating static strand tension (Ts) for
fixed speed drives.
Ts = DHP x K + Tc
NxS
Where: K = Add-on value based on D-d
C
DHP = Design horsepower of the drive
N = Number of belts on the drive
Tc = Add-on value for centrifugal force.
S = Belt speed/1000
(See Design Guide, Table 29, Page 287)
(See Design Guide, Table 31, Page 291)
This formula will produce a tension ratio of 5:1 once the drive is operating
at the design horsepower.
Drive Design – Stress Fatigue
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Stress Fatigue
Stress Fatigue Analysis
• Design Method
Tensions
 Drive Speeds
 Sheave / Pulley Diameters
 Belt Length
• Estimates Belt Life in Hours
• Evaluates Various Drive Conditions
• Compares New Drive with an Existing Drive
• Variance Between Calculated Life & Actual Service Life
• Manual versus Computer System
Drive Design – Geometry
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Geometry
Drive Layout
Idler
Dr
Dn
Drive Design – Geometry
Drive Layout
• Relative sheave arrangement
• Sub-minimum diameter sheaves
• Maximize belt wrap (AOC)
• Minimize misalignment
• Avoid interference with other machine components
• Utilize proper belt guides / restraints
• Avoid long unsupported spans
• Belt installation and take-up provisions
Drive Design – Geometry
Idlers
• Lawn & Garden drives make extensive use of idlers
• Location in Span
• Location on Inside
• Belt Wrap
• Diameters
• Face Width
• Flat Idler Crowns
• Flanging Requirements
Reference ASAE S211.5 and RMA bulletin IP-3-6
Drive Design – Geometry
Sheaves
• Avoid Using Sub-Minimum Diameters
HA
AW
HB
3.0 (80mm)
5.4 (140mm)
5.4 (140mm)
• Deep Groove Sheaves
Clutching Drives
Misaligned Drives
Twist (Mule) Drives
Quarter Drives
• Sheave Condition
• Surface Finish
• Avoid Sharp Edges
Drive Design – Geometry
Effective versus Pitch Diameter
• Pitch Diameter
• Effective Diameter
• Effective Diameter / Pitch Diameter Relationships
• Relationship of the AW Cross-Section Belt
Drive Design – Geometry
Assume HA Deep Groove Sheaves 102.0mm EOD (for HA Belt)
HA PD Calculation
102.00 mm
- 6.35 mm
95.65 mm = PD
AW EOD Calculation
102.00 mm
+ 4.90 mm
106.90 mm = EOD
i
AW PD Calculation
106.90 mm
- 6.60 mm
100.30 mm = PD
Drive Design – Geometry
Assume HB Groove 127.0m EOD (for HB Belt)
HB PD Calculation
127.00 mm
- 8.89 mm
118.11 mm = PD
AW EOD Calculation
127.00 mm
- 6.96 mm
120.04 mm = EOD
i
AW PD Calculation
120.04 mm
- 6.60 mm
113.44 mm = PD
Drive Design – Geometry
Effective Diameter Relationships
AW
Note: Dimensions shown above are millimeters, and are based on sheave radius.
AW to HA = 4.90mm (0.193”)
AW to HB = 6.96mm (0.274”)
HA to HB = 11.86mm (0.467”)
Drive Design – Geometry
Pitch Diameter Relationships
AW
Note: Dimensions shown above are millimeters, and are based on sheave radius.
2a Values
HA = 6.35mm (0.25”)
HB = 8.89mm (0.35”)
AW = 6.60mm (0.26”)
AW to HA = 4.65mm (0.183”)
AW to HB = 4.67mm (0.184”)
HA to HB = 9.32mm (0.367”)
Drive Design – Multiple Plane
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Multiple Plane
Three Basic Types
• Quarter Turn
• Mule
• Crossed Belt (180 degree Twist)
Reference ASAE S211.5 and RMA IP-3-10
Drive Design – Multiple Plane
Quarter Turn Drives
Drive Design – Multiple Plane
Quarter Turn Drives
• Use Deep Groove Sheaves
• Not Recommended for Drives with Speed Ratios > 2.5
• Minimum Center Distance: 5.5 x (D + Fb)*
•
•
•
*
D = Diameter Large Sheave
Fb = Belt Top Width
The center of the face of the sheave on the vertical shaft shall be below
the axis of the horizontal shaft by amount ‘e’ which is dependent on the
center distance.
Up to 39”
e = 0.2”
40” to 59”
e = 0.4”
60” to 99”
e = 0.5”
Direction of Rotation must be such that the Tight Side of the drive is on
the bottom.
The axis of the Vertical Shaft shall lie in a plane perpendicular to the
horizontal shaft, and intersecting it at the center of the face of the
sheave on the horizontal shaft. (See Top View)
For 1/8 Turn Drives, use 4.0 instead of 5.5 in the Formula.
Drive Design – Multiple Plane
Mule Drives
Key Points:
• Use Deep Groove Sheaves
• Alignment Very Important (Idler Positioning)
• Construction Considerations
- Low Modulus Cord
- Low Coefficient of Friction Wrap
• Minimum Spans for 90 Degree Twist Angles:
HA = 9.0” HB = 11.0” AW = 12.0”
• Minimum Spans for Other Twist Angles:
Span at 90° x Angle/90°
Ex: HA Belt at 45° Twist
9.0” x (45°/90°) = 4.5”
Drive Design – Misalignment
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Misalignment
Two Basic Types of Misalignment
• Off-Set (common in mower deck drives)
• Angular (cocked sheaves)
Proper
Parallel Horizontal
Vertical
(Off-Set)
Angular
Angular
Drive Design – Misalignment
Common Mower Deck Drive
Drive Design – Misalignment
• Use Deep Groove Sheaves
• Recommended Maximum Misalignment 5 Degrees
• Concerns and Problems
Belt Rollover
Edge Cord Failures
Belt Take-Up Provisions
Related Component Issues
• Minimize Tight Strand Misalignment
• Belt Construction and Profiles
Polyester vs. Aramid Cord
HA vs. AW Section
Drive Design – Idlers
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Idlers
Spring Loaded Idlers
• Constant Tension Characteristics
Reduced Maintenance
Pretensioning avoided
Tensions proportional to Loads Transmitted
Higher Peak Load Transmission Possible
• Idler Location
• Not Recommended for Reversing Drives
• Concerns with High Shock or Pulsating Drives
• Belt Installation and Take-Up Concerns
Drive Design – Idlers
Calculation of Idler Shaft Loads
F
a
Idler Force = 2T sin a
2
Drive Design – Idlers
Drive Tensions – Fixed vs. Moveable Idler
10 Hp at 2100 RPM
T = 125 Lbs + 25 Lbs = 150 Lbs
R = 5:1
No Load
10 Hp at 2100 RPM
T = 125 Lbs + 25 Lbs = 150 Lbs
R = 5:1
T = 75 Lbs + 75 Lbs = 150 Lbs
R = 1.0:1
No Load
T = 25 Lbs + 25 Lbs = 50 Lbs
R = 1.0:1
15 Hp at 2100 RPM
T = 188 Lbs + 37 Lbs = 225 Lbs
R = 5:1
15 Hp at 2100 RPM
T = 175 Lbs + 25 Lbs = 200 Lbs
R = 7:1
Drive Design – Tolerances
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Tolerances
Guidelines
Belt
Section
Special
Y
1089
Tol. On
Y
T
+/- 5
289 N
G
(Min)
12.45
W
+/- 0.05
12.45
A
+/- 0 20’
32
O.D.
+/-0.05
80.85
Ride
3.1
+/-1.0
Belt Section
Drive Design – Tolerances
Guidelines
Length Range
‘Y’ Tolerance
ASAE Tolerance
Up to 1000mm (39”)
+/- 3mm (.118”)
+/- 5mm (.197”)
1000mm to 1500mm (39” to 59”)
+/- 4mm (.157”)
+/- 5mm (.197”)
1500mm to 2500mm (59” to 98”)
+/- 5mm (.197”)
+/- 6.5mm (.256”)
2500mm to 4000mm (98” to 157”)
+/- 6mm (.236”)
+/- 8/10mm(.32”/.39”)
Note: Consider these as MINIMUM tolerances under normal circumstances.
Drive Design – Software
General Drive Design
• Power Transmission and V-Belt Theory
• Static and Dynamic Tension
• Stress Fatigue Analysis
• Drive Geometry
• Multiple Plane Drives
• Misalignment
• Spring Loaded Idlers
• Tolerances
• Drive Analysis Software
Drive Design – Software
Drive Design – Software
• Order from customer service 866-773-2926
Part # 109022
• Download from website
http://www.cptbelts.com/customercenter/drivepro
Product Description
Materials
Cost Drivers
General Drive Design
Additional Considerations
Additional Considerations
• Safety / Liability
• Failure Analysis
• Testing Capabilities
Drive
Considerations
Additional Considerations
– Safety/Liability
Proper Guard Design
• Sufficient Strength
• Prevent Accidental Contact
• Caution Labels
• Prevent Dirt and Debris from Entering the Drive
• Reduction of Noise
• Ventilation
Additional Considerations – Safety/Liability
Static Conductive Belts
• Explosive Environments
• Potential Fire Hazard
• Shock / Human Contact
Additional Considerations – Safety/Liability
Clutching Drives
•Do not use high thermal shrinkage cord
•Safety of person should not depend on
belt function
Additional Considerations – Failure Analysis
Leading Causes of Belt Failure
•
•
•
•
•
•
Improper Tensioning
Misalignment
Related Component Defects
Abrasive Conditions
Unusual Loading Cycles
Operating Temperature
Additional Considerations – Failure Analysis
Symptoms of Drive Problems
•
•
•
•
•
•
•
Flex Cracking
Shock Break
Belt Slippage
Rollover
Jumping Off Sheaves
Belt Squeal
Premature Wear
Additional Considerations – Testing
Testing Capabilities
• Materials Testing
• Static Product Testing
• Bench Tests
• Application Specific Testing
Additional Considerations – Testing
Materials Testing
• Rubber
– Raw material
– Mixed compounds
• Cord
– Raw material
– Treated cord
• Fabric
– Raw material
– Coated/Treated fabric
Additional Considerations – Testing
Static Product Testing
• Tensile / Elongation
• Adhesion
• Belt Size / Length
• Belt Variation / Deflection
• Static Conductivity
Additional Considerations – Testing
Bench Tests
• Dead Weight Testers
• Waterbrake / Differential Testers
Additional Considerations – Testing
4 Pulley Dead Weight Test
with back side idler
• Constant tension supplied
by weight on lower pulley
• Constant speed provided
by electric motor connected
to top pulley
• Adjustable alignment angle
• Small diameter pulleys and
backside pulley
Additional Considerations – Testing
4 Pulley Power Test
• Constant tension supplied by
weights on driven pulley
• Constant speed from electric
motor on driver pulley
• Constant HP load supplied
by generator on driven
pulley
• Small inside and backside
idler
• Adjustable alignment angle
Additional Considerations – Testing
High HP Variable Speed Tester
• 2200 RPM driver
• 300 HP load capability
• Computer controlled
speed and load cycle
Additional Considerations – Testing
CVT Drive Test
• Production clutch
mechanism
• Adjustable center
distance
• Computer controlled
speed and load cycle
Additional Considerations – Testing
Traction Drive Test
• Production tensioning
mechanism
• Constant speed from
electric motor on
driver pulley
• Constant HP load
supplied by water
brake on driven pulley
Additional Considerations – Testing
Application-Specific Testing
• Special Drive Configuration Testing
• Special Customer Machine Testing
www.CarlisleBelts.com
from
www.c-rproducts.com
[email protected]
Tel: +44 1327 701030
Fax: +44 1327 701031