JPH0483915A - Rolling bearing - Google Patents

Abstract

PURPOSE:To minimize wear of a carbon rolling body even under heavy-load condition so as to increase its service life by providing the carbon rolling body with a carbon density of 1.55g/cm<3> or more and a hardness higher than that of metal races. CONSTITUTION:A ball 3 provided between an inner and outer metal races 1 and 2 has a carbon density of 1.55g/cm<3> or more and has a hardness higher than that of the inner and outer metal races 1 and 2. This prevents non- lubricated status which may be caused by worn out solid lubricating agent and minimizes friction of the ball 3, thus extending the service life.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to non-lubricated rolling bearings used in fields such as the food industry and the semiconductor industry that require high cleanliness in working rooms.

[Conventional technology]

In environments where it is difficult to use lubricants such as oil and grease, solid lubricants are used as lubricants for bearings. A widely used method for using solid lubricants is to coat the surfaces of bearing components with solid lubricants, but this has the disadvantage that once the coating is worn away, there will be no lubrication and the life of the bearing will be shortened. There is. Therefore, the applicant previously developed a bearing in which the rolling elements themselves were made of carbon, which is a solid lubricant, and the hardness of the rolling elements was higher than that of the raceway (Utility Model Application Publication No. 63-22
Publication No. 425). In this bearing, the rolling elements themselves are made of solid lubricant, so unlike bearings in which solid lubricant is formed as a coating film on the surface of the rolling elements, solid lubricant is constantly supplied by the rolling elements, and the bearing will never become unlubricated. Furthermore, the hardness of the rolling elements is made higher than the hardness of the bearing ring to prevent further wear of the rolling elements.

[Problem to be solved by the invention]

However, the rolling elements described above are inherently brittle due to the nature of carbon and wear out when used under high loads, and their use has been limited to low load conditions. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rolling bearing that can minimize the wear of rolling elements made of carphone even under high load conditions, and thus has a long life.

[Means to solve the problem]

The inventors of the present invention conducted various experiments in order to produce rolling elements made of carphone that do not wear much even under high load conditions. As a result, in order to prevent wear of the rolling elements under high load conditions, it is insufficient to simply make the hardness of the rolling elements greater than that of the raceway, and the carbon density must be increased.
g/cm' or more? I discovered that I needed to rub it. This carbon density of 155 g/cm3 has a critical meaning. Incidentally, the carbon density of all the rolling elements made of conventional carphones was less than 1.54 g/cm3. Therefore, the rolling bearing of the present invention includes a bearing ring made of metal, rolling elements made of carphone, and a cage that holds the rolling elements, and the rolling elements are set higher than the bearing ring.
A rolling bearing having hardness is characterized in that the density of the carboxylic material is 1.55 g/Cm3 or more.

[Effect]

The carphones forming the rolling elements provide lubrication between the rolling elements and the raceway. Also, even under high load conditions, the wear of the rolling elements is extremely small, resulting in a long bearing life.

【Example】

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. FIG. 1 is a cross-sectional view of a ball bearing, which is an example of the rolling bearing of the present invention, in which 1.2 is an inner ring, an outer ring, and 3 are bearing rings, respectively.
is a hole as an example of a rolling element that rotates on its own axis and then revolves on the race la of the inner ring l and the race 2a of the outer ring 2;
5 is an upper retainer for holding the plurality of poles 3 at regular intervals, and 6 is a shield plate. The inner ring 1 and outer ring 2 are made of 5US630, and the knoll plate 6 is made of 5US304. On the other hand, the above-mentioned pole 3 is made of self-lubricating carbon, and the above-mentioned retainer 5 is also made of self-lubricating fluororesin. The orientation is transferred and further transferred to the outer ring 1.2.At this time, since the cage 5 is an upper cage,
This eliminates the need to restrict the hole 3 excessively, and provides greater flexibility to follow the various movements of the hole 3.
Always guide the hole 3 well and move the pole 3 from the retainer 5.
Optimal supply of transfer film to. At this time, the abrasion powder of the pole 3 generated by transfer wear is adsorbed by the fluororesin transfer film from the cage 5, effectively suppressing dust generation from the bearing. The Vickers hardness of the metal inner and outer rings of this example is 1.2 (
Hv) is 700, Hv of the carbon hole 3 is 1
700, both have sufficient strength, and the pole 3 has a higher hardness than the inner and outer rings 1.2. Further, in order to prevent the progression of wear of the pawl 3, the relationship between the hardnesses of the two is set such that Hv (pole)≧1.5Hv (inner and outer rings). Next, a method of manufacturing the hole 3 will be explained. Third
The figure shows the manufacturing process. First, carbon, which is the material C of pole 3, was prepared using the CIP method (
Press by cold isostatic pressing (cold isostatic pressing method). This method is the third
As shown in Figure (a), a rubber mold 11 filled with material (carphone) C for one pole is placed in a pressure vessel IO containing a pressure medium 12 such as water, and the rubber mold Material pressing is performed by pressing 11 isotropically, that is, evenly from all directions. In this process, the density of carbon is 1.55 g/cm3
The above shall apply. After that, the pressed carbon was taken out from the rubber mold 11 and heated to 1000 to 1300°C as shown in Figure 3(b).
Program fired for one week. Thereafter, as shown in FIG. 3(C), the fired carbon is polished to complete the production of the pole 3. The ball bearing of this example with the above configuration (carbon density! 55g/
cm3 or more) and a conventional ball bearing (carbon density 1.54 g/cm3 or less) that differs only in carbon density from this example, the amount of hole wear versus rotation time was measured. FIG. 2 is a diagram showing the test results. As shown in the drawing, the test conditions were a rotation speed of 50 O.
r, p, m, load is Fr=40kgf, Fa=Okt
J, temperature is room temperature. As can be seen from this figure, there is a significant difference between the amount of pole wear in the conventional ball bearing and the amount of hole wear in the ball bearing of this embodiment. In other words, carbon density is 1.54
g/cm3 is the critical point, carbon density is 1.54g
/cm' or less, the holes are worn out by nearly 200 μm after approximately 500 hours of rotation; on the other hand, when the carbon density is 1.55 g/cm3 or more, the holes are worn out after approximately 1000 hours of rotation. The hole wear amount is 10μ
It is kept at around m. As demonstrated by this test result, the ball bearing of this example, which has a carbon density of 55 g/am3 or higher, has extremely minimal wear on the poles even under high load conditions, and can withstand long-term use. can. It should be noted that this embodiment can be used not only for ball bearings but also for roller bearings, and of course can also be used for thrust bearings in addition to radial bearings. Furthermore, in this embodiment, an upper cage made of fluororesin is used, but since the balls 3 themselves have self-lubricating properties, a corrugated cage made of stainless steel such as 5US304 may also be used. Further, although 5US630 is used for the inner and outer rings 1.2, 5O9440C may be used, or other bearing steel or stainless steel may be used.

【Effect of the invention】

As is clear from the above, the rolling bearing of the present invention includes a bearing ring made of metal, a rolling element made of carbon,
In a rolling bearing comprising a cage for holding the rolling elements, the rolling elements having a higher hardness than the bearing ring, the carbon has a density of 1.55 g/am' or more, so that solid lubricant In addition to preventing the occurrence of a non-lubricated state due to wear and tear, even when used under high load conditions, the wear of the rolling elements is extremely small, resulting in a long life.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a ball bearing that is an embodiment of the present invention, Figure 2 is a diagram showing the amount of hole wear versus rotation time in the rolling bearing of the present invention and a conventional rolling bearing. FIG. 3 is a process diagram showing a method for manufacturing the pole shown in the figure. ■ - Inner ring, 2 - Outer ring, 3-pole, 5 - Cage, 6
...Nold board. 9J1 figure

Claims (1)

[Claims] (1) A rolling bearing comprising a raceway ring made of metal, a rolling element made of carbon, and a cage for holding the rolling element, the rolling element having a higher hardness than the raceway, A rolling bearing characterized in that the carbon has a density of 1.55 g/cm^3 or more.