-379 1 -380 1 Oil Free Bushings - Technical Information Q Oil Free Bushings Selection Procedure Q Calculating Oil Free Bushings Service Life (Wear) The service life of Oil Free Bushings is determined by the wear amount. The wear amount calculated will greatly differ by the conditions, such as surface pressure, sliding speed, movement type, lubrication, surface roughness of the mating shaft, etc. Provided that the wear amount is proportional to the load and the sliding distance, the following formula is generally used to calculate the wear amount. Use this as an indication for you to select a specification. Estimated wear amount (mm) W=K* 1 xPxVxT Specific Wear Rate K : mm/(N/mm 2 • m/s • Hr) Design Surface Pressure P : N/mm 2 Sliding Speed V : m/s Friction Time T : Hr-hr Q Oil Free Bushings Securing Method 1Press-Fit To press-fit the Oil Free Bushings, make sure to do it gently using a vise or a press. To make this operation easier, install a chamfering on the edge of the housing I.D. We recommend that you apply a little amount of lubricant to the housing. 2Rotation Stopper Screw/Bonding If you want to emphasize on preventing Oil Free Bushings from falling off or rotating, we recommend the following methods according to your operating conditions and environment. * 2 *1 Specific wear rate range Lubrication mm/(N/mm 2 • m/s • Hr) mm/(kgf/cm 2 • m/min • Hr) Unlubricated 3x10 -3 ~6x10 -4 1~5x10 -6 Regular 3x10 -4 ~6x10 -5 1~5x10 -7 Oil 3x10 -5 ~6x10 -6 1~5x10 -8 NG Determine the operating conditions - General usage, heat resistance, chemical resistance, load, usage frequency, with or without lubrication • Select the shape such as Straight/Flanged • Temporary select the size and dimensions from the design conditions. P.377, 378 • Permissible maximum load Make sure that the load falls within the permissible maximum load range. P.380 • Permissible maximum speed Make sure that the travel speed falls within the permissible maximum speed range. P.380 • Service life (wear amount calculation) Calculate the estimated wear amount to verify the necessary life hours can be secured. P.379 Press Fit Fixture Load Bushing Housing Calculation Example Bearing of I.D. 20mm/Length 10mm, Load 1000N without lubricant, Rotational speed 2r/min When used for 100 hours of friction time = Specific Wear Rate× x x Operating Time = × x x 100 = 0.0028(mm) Load I.D. x Length 1000 20×10 3 1000 π x I.D. x Rotational Speed 1000 πx20x2 1000 W = K x P x V x T Chamfer Determine the operating condition Temporary specification selection Basic safety check Selection complete Q Material Properties and Environmental Tolerances (Reference Value) Q Mechanical Properties (Reference Value) Characteristics Unit Copper Alloy Bronze Multi-Layer LF High Precision Resin Type (Polyacetal Resin) Resin Type (PTFE) Casting Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method Density g/cm 3 7.8 - 8.5 - - - - - - - - - - - Tensile Strength N/mm 2 {kgf/mm 2 } 755 {77.0} JIS Z 2241 150 {15.0} JIS Z 2241 380 {38.7} JIS Z 2241 12 {1.2} ASTM D 638 51.0 {5.2} ASTM D 638 13.1 {1.3} ASTM D 638 245 (25.0) - Tensile Elongation after Fracture % 12 JIS Z 2241 - - - - - - 60 ASTM D 638 150 ASTM D 638 - - Elongation % - - - - 27 JIS Z 2241 171 ASTM D 638 - - - - - - Flexural Strength N/mm 2 {kgf/mm 2 } - - - - - - - - 76.5{7.8} ASTM D 790 - - - - Flexural Modulus N/mm 2 {kgf/mm 2 } - - - - - - - - 2,650{270.2} ASTM D 790 - - - - Compression Strength N/mm 2 {kgf/mm 2 } - - - - - - - - - - - - - - Compression Yield Strength N/mm 2 {kgf/mm 2 } 345 {35.0} - - - - - - - - - - - - - Compression Stress 1% Deformation N/mm 2 {kgf/mm 2 } - - - - - - - - 21.1 {2.2} ASTM D 695 10.5 {1.1} ASTM D 695 - - 10% Deformation 81.9 {8.4} 23.0 {2.3} ASTM D 695 Impact Strength J/cm {kgfm/cm} 19{1.9} JIS Z 2242 - - - - - - 58.8 {6.0} ASTM D 256 - - - - Hardness - HB210 JIS Z 2243,2245 HB 60 JIS Z 2243 - - HDD62 ASTM D 2240 HRM72 ASTM D 785 HRR25 ASTM D 785 HB240 - Young's Modulus N/mm 2 {kgf/mm 2 } 105,000 {10,700} JIS Z 2241 - - - - - - - - - - - - Linear Thermal Expansion Coefficient x10 -5 °C -1 2.2 - - - - - 9~9.75 ASTM D 696 8~13 ASTM D 696 9~11 ASTM D 696 0.92~1.18 - Thermal Conductivity W/m°C {cal/sec°C cm} 0.009 {0.21} - - - - - - - - - - - - - Melting Point °C - - - - - - - - 165 DSC 327 DSC - - Specific Gravity - - - - - - - 1.98 ASTM D 792 1.39 ASTM D 792 2.25 ASTM D 792 7.1 - UL Flammability - - - - - - - - - HB UL94 - - - - Page P.381~390 P.391, 392 P.398~400 P.399 P.401 P.397 Type Copper Alloy Bronze Multi-Layer LF High Precision Resin Type (Polyacetal Resin) Resin Type (PTFE) Casting Shape Material Properties Composite products with embedded solid lubricant in high-tensile brass. Porous bronze casting soaked in lubricant Composite product consisting of three layers: steel-backed metal layer, sintered bronze layer and filler added PTFE layer. Fluororesin is bonded on duralumin (A2017). Polyacetal resin with added lubricant and special fillers. PTFE with added friction- resisting filler and solid lubricant Molybdenum Disulfide is embedded spirally in FC250. Lubrication Regular Unlubricated Regular Oil Unlubricated Unlubricated Unlubricated Unlubricated Regular Unlubricated Rotation g g g g g g g Oscillating Motion g g g g g g g Reciprocating Motion g g g g g g g Operating Temp. Range (°C) -40~200 -40~150 -40~150 -195~280 -50~140 -40~80 -200~200 -40~150 Electrical Conductivity Provided Provided Provided Not provided Not provided Volume Resistivity: 3x10 2 Ω • cm 2 Provided Environmental Conditions In Air g g g g g g g In Oil g g G n g g g In Water - n n r n r g n In Seawater - n n n n r g n In Chemical - n n r n r g n In Corrosive Atmosphere r r n r g r g n Maximum Allowable Load (Bottom C-VALUE Products Specifications) 29.0(98.0) 20.3(68.6) N/mm 2 10N/mm 2 49.0(137)N/mm 2 6N/mm 2 17.5N/mm 2 7N/mm 2 8N/mm 2 5N/mm 2 296(1,000) 207 (700) kgf/cm 2 102kgf/cm 2 500(1400)kgf/cm 2 61kgf/cm 2 179kgf/cm 2 71kgf/cm 2 82kgf/cm 2 51kgf/cm 2 Maximum Allowable Velocity (Bottom C-VALUE Products Specifications) 1.00 0.7 m/s 0.5 0.35 m/s 1.66m/s 5.0m/s 0.65m/s 3.33m/s 0.85m/s 1.65m/s 0.25m/s 0.15m/s 60 42 m/min 30 21 m/min 100m/min 300m/min 39m/min 200m/min 51m/min 99m/min 15m/min 9m/min Maximum Allowable PV Value (Bottom C-VALUE Products Specifications) 3.25 2.28 N/mm 2 • m/s 1.65 1.16 N/mm 2 • m/s 1.65 N/mm 2 • m/s 3.25 N/mm 2 • m/s 3.60 N/mm 2 • m/s 0.98 N/mm 2 • m/s 2.45 N/mm 2 • m/s 1 N/mm 2 • m/s 0.8 N/mm 2 • m/s 0.5 N/mm 2 • m/s 1,990 1,393 kgf/cm 2 • m/min 1,010 707 kgf/cm 2 • m/min 1,000 kgf/cm 2 • m/min 2,000 kgf/cm 2 • m/min 2,200 kgf/cm 2 • m/min 600 kgf/cm 2 • m/min 1,500 kgf/cm 2 • m/min 612 kgf/cm 2 • m/min 490 kgf/cm 2 • m/min 306 kgf/cm 2 • m/min Environmental Condition Δ - Applicable only under certain conditions. Some values for Casting Type are for reference only. Values for High Precision Type are values for the sliding material. Values in ( ): Allowable Static Surface Pressure (no sliding motion or sliding at extremely low speed) EListed values are not standard values but reference values. Rotation Stopper Screw Rotation Stopper Screw Adhesive Housing Bushing Apply Adhesives on Outer Cylinder *2 Using the rotation stopper screw is recommended for a heavy load at a high temperature.
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-3791 -3801
Oil Free Bushings - Technical Information
C_0379-0380_F06-06_cENGC_0379-0380_F06-06_cENG cENG 2nd
Q Oil Free Bushings Selection Procedure
Q Calculating Oil Free Bushings Service Life (Wear) The service life of Oil Free Bushings is determined by the wear amount. The wear amount calculated will greatly differ by the conditions, such as surface pressure, sliding speed, movement type, lubrication, surface roughness of the mating shaft, etc. Provided that the wear amount is proportional to the load and the sliding distance, the following formula is generally used to calculate the wear amount. Use this as an indication for you to select a specifi cation.
Estimated wear amount (mm) W=K*1xPxVxTSpecifi c Wear Rate K : mm/(N/mm2 • m/s • Hr)Design Surface Pressure P : N/mm2
Sliding Speed V : m/sFriction Time T : Hr-hr
Q Oil Free Bushings Securing Method1Press-Fit To press-fi t the Oil Free Bushings, make sure to do it
gently using a vise or a press. To make this operation easier, install a chamfering on
the edge of the housing I.D. We recommend that you apply a little amount of lubricant to the housing.
2Rotation Stopper Screw/Bonding If you want to emphasize on preventing Oil Free Bushings from
falling off or rotating, we recommend the following methods according to your operating conditions and environment. *2
*1 Specifi c wear rate range
Lubrication mm/(N/mm2 • m/s • Hr) mm/(kgf/cm2 • m/min • Hr)
Unlubricated 3x10-3~6x10-4 1~5x10-6
Regular 3x10-4~6x10-5 1~5x10-7
Oil 3x10-5~6x10-6 1~5x10-8
NG
Determine the operating conditions - General usage, heat resistance, chemical resistance, load, usage frequency, with or without lubrication
• Select the shape such as Straight/Flanged• Temporary select the size and dimensions from the design conditions. P.377, 378
• Permissible maximum load Make sure that the load falls within the permissible maximum load range. P.380
• Permissible maximum speed Make sure that the travel speed falls within the permissible maximum speed range. P.380
• Service life (wear amount calculation) Calculate the estimated wear amount to verify the necessary life hours can be secured. P.379
Press Fit Fixture
Load
Bushing
Housing
Calculation ExampleBearing of I.D. 20mm/Length 10mm, Load 1000N without lubricant, Rotational speed 2r/minWhen used for 100 hours of friction time
= Specifi c Wear Rate × x x Operating Time
= × x x 100
= 0.0028(mm)
LoadI.D. x Length
100020×10
31000
π x I.D. x Rotational Speed1000
πx20x21000
W = K x P x V x T
Chamfer
Determine the operating condition
Temporary specifi cation selection
Basic safety check
Selection complete
Q Material Properties and Environmental Tolerances (Reference Value)
Q Mechanical Properties (Reference Value)
Characteristics UnitCopper Alloy Bronze Multi-Layer LF High Precision Resin Type
(Polyacetal Resin)Resin Type
(PTFE) Casting
Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method Value Testing Method
Density g/cm3 7.8 - 8.5 - - - - - - - - - - -
Tensile Strength
N/mm2
kgf/mm2755
77.0 JIS Z 2241 15015.0 JIS Z 2241 380
38.7 JIS Z 2241 121.2 ASTM D 638 51.0
5.2 ASTM D 638 13.11.3 ASTM D 638 245
(25.0) -
Tensile Elongation after Fracture % 12 JIS Z 2241 - - - - - - 60 ASTM D 638 150 ASTM D 638 - -
Elongation % - - - - 27 JIS Z 2241 171 ASTM D 638 - - - - - -
Flexural Strength N/mm2
kgf/mm2 - - - - - - - - 76.57.8 ASTM D 790 - - - -
Flexural Modulus N/mm2
kgf/mm2 - - - - - - - - 2,650270.2 ASTM D 790 - - - -
Compression Strength
N/mm2
kgf/mm2 - - - - - - - - - - - - - -
Compression Yield Strength
N/mm2
kgf/mm2345
35.0 - - - - - - - - - - - - -
Compression Stress
1%Deformation N/mm2
kgf/mm2 - - - - - - - -
21.12.2
ASTM D 695
10.51.1 ASTM D 695
- -10%
Deformation81.98.4
23.02.3 ASTM D 695
Impact Strength
J/cmkgfm/cm 191.9 JIS Z 2242 - - - - - - 58.8
6.0 ASTM D 256 - - - -
Hardness - HB210 JIS Z 2243,2245 HB 60 JIS Z 2243 - - HDD62 ASTM D
2240 HRM72 ASTM D 785 HRR25 ASTM D 785 HB240 -
Young's Modulus
N/mm2
kgf/mm2105,00010,700 JIS Z 2241 - - - - - - - - - - - -
Linear Thermal Expansion Coeffi cient x10-5°C-1 2.2 - - - - - 9~9.75 ASTM D 696 8~13 ASTM D 696 9~11 ASTM D 696 0.92~1.18 -
Thermal Conductivity
W/m°Ccal/sec°C cm
0.0090.21 - - - - - - - - - - - - -
Melting Point °C - - - - - - - - 165 DSC 327 DSC - -
Specifi c Gravity - - - - - - - 1.98 ASTM D 792 1.39 ASTM D 792 2.25 ASTM D 792 7.1 -
UL Flammability - - - - - - - - - HB UL94 - - - -
Page P.381~390 P.391, 392 P.398~400 P.399 P.401 P.397
Type Copper Alloy Bronze Multi-Layer LF High Precision Resin Type(Polyacetal Resin)
Resin Type(PTFE) Casting
Shape
Material Properties
Composi te products with embedded solid lubricant in high-tensile brass.
Porous bronze casting soaked in lubricant
C o m p o s i t e p r o d u c t cons i s t i ng o f t h ree layers: steel-backed metal layer, sintered bronze layer and filler added PTFE layer.
Fluororesin is bonded on duralumin (A2017).
Po lyaceta l res in wi th a d d e d l u b r i c a n t a n d special fi llers.
PTFE with added friction-resisting filler and solid lubricant
Molybdenum Disulfide is embedded spirally in FC250.
Lubrication Regular Unlubricated Regular Oil Unlubricated Unlubricated Unlubricated Unlubricated Regular Unlubricated
Rotation g g g g g g g
Oscillating Motion g g g g g g g
Reciprocating Motion g g g g g g g
Operating Temp. Range (°C) -40~200 -40~150 -40~150 -195~280 -50~140 -40~80 -200~200 -40~150
Electrical Conductivity Provided Provided Provided Not provided Not provided Volume Resistivity:
3x102Ω • cm2 Provided
Env
iro
nmen
tal
Co
ndit
ions
In Air g g g g g g g
In Oil g g G n g g g
In Water - n n r n r g n
In Seawater - n n n n r g n
In Chemical - n n r n r g nIn Corrosive Atmosphere r r n r g r g n
Maximum Allowable Load
(Bottom C-VALUE Products Specifi cations)
29.0(98.0)20.3(68.6)
N/mm210N/mm2 49.0(137)N/mm2 6N/mm2 17.5N/mm2 7N/mm2 8N/mm2 5N/mm2
296(1,000)207 (700)
kgf/cm2102kgf/cm2 500(1400)kgf/cm2 61kgf/cm2 179kgf/cm2 71kgf/cm2 82kgf/cm2 51kgf/cm2
Maximum Allowable Velocity
(Bottom C-VALUE Products Specifi cations)
1.000.7m/s
0.5 0.35m/s
1.66m/s 5.0m/s 0.65m/s 3.33m/s 0.85m/s 1.65m/s 0.25m/s 0.15m/s6042
m/min
3021
m/min100m/min 300m/min 39m/min 200m/min 51m/min 99m/min 15m/min 9m/min
Maximum Allowable PV Value
(Bottom C-VALUE Products Specifi cations)
3.252.28
N/mm2 • m/s
1.651.16
N/mm2 • m/s
1.65 N/mm2 • m/s
3.25 N/mm2 • m/s
3.60N/mm2 • m/s
0.98N/mm2 • m/s
2.45N/mm2 • m/s
1N/mm2 • m/s
0.8N/mm2 • m/s
0.5N/mm2 • m/s
1,9901,393
kgf/cm2 • m/min
1,010707
kgf/cm2 • m/min
1,000kgf/cm2 • m/min
2,000kgf/cm2 • m/min
2,200kgf/cm2 • m/min
600kgf/cm2 • m/min
1,500kgf/cm2 • m/min
612kgf/cm2 • m/min
490kgf/cm2 • m/min
306kgf/cm2 • m/min
Environmental Condition ∆ - Applicable only under certain conditions. Some values for Casting Type are for reference only. Values for High Precision Type are values for the sliding material.Values in ( ): Allowable Static Surface Pressure (no sliding motion or sliding at extremely low speed) EListed values are not standard values but reference values.
Rotation Stopper Screw
Rotation Stopper Screw
Rotation Stopper Screw
Rotation Stopper Screw
Apply Adhesives on Outer Cylinder
Adhesive
Housing
BushingApply Adhesives on Outer Cylinder
Adhesive
Housing
Bushing
*2 Using the rotation stopper screw is recommended for a heavy load at a high temperature.
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