Electroconductive grease-filled bearing
An electroconductive grease-filled bearing is a rolling bearing comprising an inner race 11 and an outer race 12 , both of the races being coaxially provided, a plurality of steel balls 13 radially being retained between track surfaces of the races, the bearing rotatably supporting the edge of heating roll 6 a in the fixing section of an electrostatic transfer copying machine, fixed to the inner periphery of inner race 11 , an electroconductive grease to be filled between the track surfaces comprising a fluorocarbon oil as a base oil and graphite (or together with polytetrafluoroethylene) as a thickening agent. The electroconductive grease has a distinguished electroconductance so as to effectively discharge the static electricity, and has a distinguished heat-resistant durability even at elevated temperatures, and also prevents revolution failure due to the increased torque caused by an excessive lowering in the grease consistency, while maintaining the good electroconductance. The bearing is most suitable for rotatably supporting a photosensitive drum or a heating roll or a pressing-heating roll in the fixing section in an electrostatic transfer copying machine, and is also effective for stabilization of printed images.
1. An electroconductive grease-filled bearing, which is a rolling bearing comprising an inner race and an outer race, both of the races being coaxially provided, a plurality of rolling elements radially being retained between track surfaces of the races, the rolling bearing rotatably supporting a shaft fitted on the inner periphery of the inner race, an electroconductive grease, which comprises a fluorocarbon oil as a base oil and graphite as a thickening agent, being filled between the track surfaces.
2. An electroconductive grease-filled bearing according to claim 1 , wherein the fluorocarbon oil as a base oil has a kinematic viscosity of 5-1,500 mm 2 /sec (40° C.).
3. An electroconductive grease-filled bearing according to claim 2 , wherein the electroconductive grease comprises 50-90% by weight of the fluorocarbon oil and 50-10% by weight of the thickening agent, sum total being 100% by weight.
4. An electroconductive grease-filled bearing according to claim 2 , wherein polytetrafluoroethylene is used as a thickening agent.
5. An electroconductive grease-filled bearing according to claim 4 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and 5-25% by weight of the polytetrafluoroethylene, sum total being 100% by weight.
6. An electroconductive grease-filled bearing according to claim 5 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
7. An electroconductive grease-filled bearing according to claim 4 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and not more than 30% by weight of the polytetrafluoroethylene, sum being 100% by weight.
8. An electroconductive grease-filled bearing according to claim 7 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
9. An electroconductive grease-filled bearing according to claim 4 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
10. An electroconductive grease-filled bearing according to claim 1 , wherein the fluorocarbon oil as a base oil has a kinematic viscosity of 250-1,000 mm 2 /sec (40° C.).
11. An electroconductive grease-filled bearing according to claim 10 , wherein the electroconductive grease comprises 50-90% by weight of the fluorocarbon oil and 50-10% by weight of the thickening agent, sum total being 100% by weight.
12. An electroconductive grease-filled bearing according to claim 10 , wherein polytetrafluoroethylene is used as a thickening agent.
13. An electroconductive grease-filled bearing according to claim 12 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and not more than 30% by weight of the polytetrafluoroethylene, sum being 100% by weight.
14. An electroconductive grease-filled bearing according to claim 13 6, wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
15. An electroconductive grease-filled bearing according to claim 12 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and 5-25% by weight of the polytetrafluoroethylene, sum total being 100% by weight.
16. An electroconductive grease-filled bearing according to claim 15 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
17. An electroconductive grease-filled bearing according to claim 12 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
18. An electroconductive grease-filled bearing according to claim 1 , wherein the graphite is amorphous graphite.
19. An electroconductive grease-filled bearing according to claim 18 , wherein the electroconductive grease comprises 50-90% by weight of the fluorocarbon oil and 50-10% by weight of the thickening agent, sum total being 100% by weight.
20. An electroconductive grease-filled bearing according to claim 18 , wherein polytetrafluoroethylene is used as a thickening agent.
21. An electroconductive grease-filled bearing according to claim 20 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and not more than 30% by weight of the polytetrafluoroethylene, sum being 100% by weight.
22. An electroconductive grease-filled bearing according to claim 21 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
23. An electroconductive grease-filled bearing according to claim 20 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and 5-25% by weight of the polytetrafluoroethylene, sum total being 100% by weight.
24. An electroconductive grease-filled bearing according to claim 23 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
25. An electroconductive grease-filled bearing according to claim 20 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
26. An electroconductive grease-filled bearing according to claim 1 , wherein the electroconductive grease comprises 50-90% by weight of the fluorocarbon oil and 50-10% by weight of the thickening agent, sum total being 100% by weight.
27. An electroconductive grease-filled bearing according to claim 1 , wherein polytetrafluoroethylene is used as a thickening agent.
28. An electroconductive grease-filled bearing according to claim 27 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and not more than 30% by weight of the polytetrafluoroethylene, sum being 100% by weight.
29. An electroconductive grease-filled bearing according to claim 28 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
30. An electroconductive grease-filled bearing according to claim 27 , wherein the electroconductive grease comprises 50-80% by weight of the fluorocarbon oil, 15-30% by weight of the graphite and 5-25% by weight of the polytetrafluoroethylene, sum total being 100% by weight.
31. An electroconductive grease-filled bearing according to claim 30 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
32. An electroconductive grease-filled bearing according to claim 27 , wherein the polytetrafluoroethylene has an average primary particle size of 0.2-15 μm.
33. An electroconductive grease-filled bearing according to claim 1 , for use in rotatably supporting a rotating roll provided in electrophotographic process machinery.
34. An electroconductive grease-filled bearing according to claim 33 , wherein the rotating roll is a photosensitive drum or a heating roll or a pressing-heating roll provided in a fixing section.