ThorPlas Engineering Manual - Thordon Bearings

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PHYSICAL PROPERTIES i) ThorPlas Typical Physical Properties 6 Figure 3: ThorPlas Typical Physical Properties – Metric & Imperial Property Unit Values Density g.ml -1 1.40 Hardness (Shore D) – 83 Tensile Strength at Break (D638) MPa (psi) 67 (9,750) Tensile Modulus of Elasticity MPa (psi) 2930 (425,000) Elongation at Break % ~10 Compression Strength (D695) MPa (psi) 105 (15,300) Compression Stress at Yield MPa (psi) 92 (13,400) Compressive Young’s Modulus of Elasticity MPa (psi) 2,410 (350,000) Compression Strain at Yield % ~8 Minimum Notched Impact Energy (D256) J.m –1 (Ft.lb.in. -1 ) 31 (0.60) Notched Specific Impact Energy (D256) J.m –2 (Ft.lb.in. -2 ) 506 (0.24) Coefficient of Linear Thermal Expansion (20-120°C) °C (°F) 4.6 x 10 -5 (2.5 x 10 -5 ) Volumetric Swell -Water, 24-h immersion (D570) Wt% 0.034 Volumetric Swell -Water, long-term immersion Vol% < 0.15 Dynamic Coefficient of Friction (0.27MPa or 40psi), dry (D3702) – ~ 0.1 Dynamic Coefficient of Friction (>200 bar or >3000psi), dry – ~ 0.10 Dynamic Coefficient of Friction (>200 bar or >3000psi), wet – 0.10-0.17 Abrasive Wear (Rotary Drum Abrasion), dry (D5963) mm 3 (in. 3 ) 195 (0.012) Melting Temperature °C (°F) > 250 (> 480) Max. Continuous Service Temp. in Air °C (°F) 110 (230) Max. Continuous Service Temp. in Water °C (°F) 80 (176) Note: Properties are typical values, unless otherwise noted, and may be altered to some extent by processing conditions.
3. Design Guide a) Application Analysis The following information should be considered when evaluating an application where ThorPlas is to be used: • shaft and housing dimensions • bearing pressure • shaft rotation and speed • type and magnitude of abrasives • type of lubrication – lubricating medium and flow rate b) Bearing Pressure Nominal bearing pressure is calculated by dividing the radial load by the projected or cross sectional area. The projected area is determined by multiplying the inside diameter (I.D.) of the bearing by the bearing length (L), as in Figure 4. The use of I.D. multiplied by bearing length (L) is a bearing industry norm for calculating the projected area for bearing pressure. Dividing the load by the projected area gives the approximate pressure. This assumes that the pressure is uniform across the area. In reality, the pressure is greatest at the 6 o’clock position and decreases in a parabolic curve to zero where the shaft starts to have clearance with the bearing. It is therefore advantageous, considering load carrying capacity, to keep running clearances to a minimum. WALL THICKNESS (1) Figure 4: Bearing Pressure I.D. LENGTH BEARING PROJECTED AREA FIG. 11 Radial load needs to be defined as maximum design load, normal operating load or a combination of static and impact loads. Furthermore, it is important to define if the load is constant or cyclic. Bearing = Radial Load = Load Pressure Projected Area Length x I.D. c) Velocity The sliding velocity or the peripheral shaft speed is also an important design factor. Velocity is an essential consideration when evaluating frictional heat generation. It is calculated by the following equation for rotating shafts. V (m/sec) or = V (fpm) = DESIGN GUIDE π dN = dN 60 x 1000 19,100 π dN 12 = 0.262 dN where V = Sliding Velocity d = Shaft Diameter (mm or in.) N = RPM of the shaft π = pi constant 3.1416 ThorPlas can work at high pressures in oscillating motion or at slow full rotation rpm. For non-hydrodynamic operation, as the peripheral velocity increases, the load on the bearing should be reviewed in conjunction with the allowable PV limit as described in Figure 5. For applications outside the PV limits, please consult with Thordon Bearings Inc. 7
Page 1 and 2: ThorPlas ® ThorPlas Bearings ® Be
Page 3 and 4: Index INDEX 1. INTRODUCTION . . . .
Page 5 and 6: 2. Physical Properties a) General T
Page 7: h) Chemical Compatibility PHYSICAL
Page 11 and 12: WAL 0.25 0.23 0.21 0.19 0.17 0.15 0
Page 13 and 14: 4. Application Design a) Applicatio
Page 15 and 16: e) Thermal Expansion Allowance As w
Page 17 and 18: h) Minimum Installed Clearance The
Page 19 and 20: APPLICATION DESIGN SAMPLES USING TH
Page 21 and 22: n) Step-by-Step Manual Calculations
Page 23 and 24: 5. Machining Instructions a) Genera
Page 25 and 26: Step 3. Sharp and smooth tool bits
Page 27 and 28: 6. Installation Guidelines a) Freez
Page 29 and 30: Appendix 1. Shaft and Housing Toler
Page 31: Customer Focused To Support Your Im

ThorPlas Engineering Manual - Thordon Bearings

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