Annular sliding fluoroplastics member, and method of producing an annular sliding fluoroplastics member
The present invention relates to an annular sliding fluoroplastics member which is requested to have good mechanical properties, resistance to abrasion and wear, thermal conductivity, heat resistance, and the like, and also to a method of producing such an annular sliding fluoroplastics member. The annular sliding fluoroplastics member of the invention has a composite structure which mainly consists of fluorine plastics and short fibers, and 20 or more wt. % of short fibers by weight of a total amount of the short fibers are oriented in a direction along which a burden of a load is large. According to this configuration, the buckling resistance and the pressure resistance are enhanced. A member having a high buckling resistance can be used in a thrust slide bearing or a thrust washer in which a large press load is applied in the axial direction, and a member having a high pressure resistance can be used in a radial slide bearing in which a large press load is applied in a radial direction. In some cases, in the annular sliding fluoroplastics member of the invention, filaments consisting of long fibers may be stitched to the inner peripheral face or the like, the surface is covered with an expanded graphite sheet, or the member is impregnated with a lubricant. The member having such a structure is excellent in buckling resistance and pressure resistance in a radial direction, and also in resistance to abrasion and wear, thermal conductivity, etc. According to the production method of the invention, a cutting work step can be omitted, and therefore materials can be prevented from being wastefully used, and the production cost can be reduced.
1. An annular sliding fluoroplastics member having a composite structure containing a plurality of layers stacked in a radial direction and coupled to one another, wherein: each layer includes fluorine plastic and short fibers; and wherein 20 or more wt. % of said short fibers by weight of a total amount of said short fibers are oriented in a direction along which the magnitude of a load is large.
2. An annular sliding fluoroplastics member according to claim 1 , wherein 20 or more wt. % of the short fibers by weight of the total amount of said short fibers are oriented in an axial direction of said annular sliding fluoroplastics member.
3. An annular sliding fluoroplastics member according to claim 1 , wherein 20 or more wt. % of the short fibers by weight of the total amount of said short fibers are oriented in a circumferential direction of said annular sliding fluoroplastics member.
4. An annular sliding fluoroplastics member according to claim 1 , wherein 20 or more wt. % of the short fibers by weight of the total amount of said short fibers are oriented in a spiral direction of said annular sliding fluoroplastics member.
5. An annular sliding fluoroplastics member according to claim 1 , wherein 50 or more wt. % of the short fibers by weight of the total amount of said short fibers are oriented in a direction along which the magnitude of a load is large.
6. An annular sliding fluoroplastics member according to claim 1 , wherein said short fibers are fibrillated aramid fibers, and said fluorine plastics is PTFE plastics.
7. An annular sliding fluoroplastics member according to claim 1 , wherein at least one surface of said annular sliding fluoroplastics member having said composite structure which mainly consists of said fluorine plastics and said short fibers is covered with an expanded graphite sheet.
8. An annular sliding fluoroplastics member according to claim 1 , wherein said annular sliding fluoroplastics member having said composite structure which mainly consists of said fluorine plastics and said short fibers is impregnated with a lubricant.
9. An annular sliding fluoroplastics member according to claim 1 , wherein each layer is coupled so that the layers do not move relative to each other in the axial direction.
10. An annular sliding fluoroplastics member according to claim 1 , wherein each of said stacked layers has a wavy sectional shape which undulates in an axial direction of said annular sliding fluoroplastics member.
11. An annular sliding fluoroplastics member according to claim 10 , wherein overlapping faces of said layers are integrally coupled to one another.
12. An annular sliding fluoroplastics member according to claim 1 , wherein plural filaments are stitched to said composite structure which mainly consists of said fluorine plastics and said short fibers.
13. An annular sliding fluoroplastics member according to claim 12 , wherein, as said filaments, long fibers selected from aramid fibers, glass fibers, polyimide fibers, and PTFE fibers which are stretched, or metal wires selected from stainless wires, aluminum wires, and copper wires are used.