JP2006170317A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing increased in fretting resistance, bearing life, and insulating property by forming a ceramics film having a function equivalent to that of a sintered ceramics in a study on a means for applying a ceramics material used in place of a sintered ceramics. <P>SOLUTION: This rolling bearing comprises an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring. The ceramics film by aerosol deposition is formed on (A) the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring and/or (B) the rolling elements. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing, and more particularly, to a rolling bearing provided with a ceramic film formed without undergoing a sintering process.

  Conventional rolling bearings use bearing steel or martensitic stainless steel as a material for the outer ring and / or inner ring for the purpose of improving fretting resistance and bearing life. Moreover, bearing steel, martensitic stainless steel, ceramics, or the like is used as the material of the rolling elements. The materials of the outer ring, the inner ring, and the rolling elements have been appropriately combined depending on the application of the rolling bearing to satisfy the function required for the application.

Furthermore, in recent years, there is one in which the function of a rolling bearing is improved by performing a nitriding treatment on the surface of the rolling element and forming a hard film (for example, Patent Document 1).
Japanese Patent Laid-Open No. 09-287058

  Conventionally, it was common to use ceramic rolling elements to improve fretting resistance, bearing life, etc., but ceramic rolling elements are mixed with foreign metal during the manufacturing process of the rolling elements, Since the sintering aid segregates on the rolling elements and becomes a defect-dominated bearing life limit starting from pores (pores), further improvement in performance cannot be expected.

  On the other hand, when ceramic materials are applied to the inner and outer rings and a ceramic film is formed on the raceways provided on the inner and outer rings, the ceramic material generally requires a process of sintering (sintering process) at 1000 ° C or higher. Therefore, the sintering process and the costs associated therewith have been a heavy burden.

  Therefore, the present invention examines means for applying ceramic materials in place of sintering, and provides a rolling bearing having improved fretting resistance, bearing life, insulation, and the like compared to a sintered ceramic film. Objective.

  In order to solve the above problems, the present invention is a rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring, and (A) the outer ring A rolling bearing is provided wherein a ceramic film is formed on the inner peripheral surface of the inner ring and the outer peripheral surface of the inner ring and / or (B) the rolling element by an aerosol deposition method.

  By adopting such a configuration, a ceramic film can be formed without passing through a sintering process, and fretting resistance, bearing life, insulation, etc. are improved compared to a ceramic film that has passed through a sintering process. An improved rolling bearing can be provided. Further, the ceramic film formed by the aerosol deposition method has almost no pores (pores), and therefore has no life limit due to defect-dominated type (peeling) or the like.

  Preferred embodiments of the invention are as follows. The ceramic film is preferably formed on a raceway surface provided on each of an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring. The above problems can be solved if a ceramic film is formed on at least the inner circumferential surface of the outer ring and the raceway surfaces provided on the outer circumferential surface of the inner ring.

  Moreover, it is preferable that the surface of the ceramic film is cut. By cutting the surface of the ceramic film, smoothness of several nm level can be obtained, and the acoustic characteristics of the rolling bearing can be improved.

  The outer ring and the inner ring are preferably made of bearing steel or martensitic stainless steel. Moreover, it is preferable that the said rolling element consists of either bearing steel, martensitic stainless steel, or ceramics. As described above, the fretting resistance and the like can be further improved by appropriately selecting the materials of the outer ring, the inner ring and the rolling elements.

The present invention also relates to a method of manufacturing a rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring. A rolling bearing manufacturing method is provided, in which a ceramic film is formed on an outer peripheral surface and an outer peripheral surface of the inner ring and / or (B) the rolling element by an aerosol deposition method.
Preferred embodiments of the invention are as follows. The speed of the ceramic fine particles in the aerosol deposition method is preferably 300 to 1000 m / sec. The average particle size of the ceramic fine particles is preferably 10 to 200 nm. The thickness of the ceramic film is preferably 0.5 μm to 1000 μm.

  According to the present invention, the ceramic film is formed by the aerosol deposition method on the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring, and the surface of the rolling element. A ceramic film can be formed at room temperature. In addition, the obtained ceramic film can provide a rolling bearing having improved fretting resistance, bearing life, insulation and the like as compared with a ceramic film formed by sintering.

  Next, a rolling bearing according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view of a rolling bearing according to a first embodiment of the present invention. A rolling bearing 1 shown in FIG. 1 includes an outer ring 10, an inner ring 12, a plurality of balls 14 as a plurality of rolling elements disposed between the outer ring 10 and the inner ring 12, and a plurality of balls. And a retainer 16 for separating 14 at predetermined intervals. The ceramic film 20 is formed on the raceway surfaces 13 of the outer ring 10 and the inner ring 12 (the raceway surface on the outer ring 10 side is not shown), and the ceramic film 20 is also formed on the balls 14 as rolling elements. Yes.

  FIG. 2 is a partial cross-sectional view of the rolling bearing 2 according to the second embodiment. In the rolling bearing 2 shown in FIG. 2, the ceramic film C is formed on the raceway surfaces 13 of the outer ring 10 and the inner ring 12 (the raceway surface on the outer ring 10 side is not shown). However, a ceramic film is not formed on the balls 14 in the rolling bearing 2 according to the present embodiment.

  FIG. 3 is a partial cross-sectional view of the rolling bearing 3 according to the second embodiment. In the rolling bearing 3 illustrated in FIG. 3, a ceramic film C is formed on the balls 14. However, a ceramic film is not formed on each raceway surface 13 of the outer ring 10 and the inner ring 12 (the raceway surface on the outer ring 10 side is not shown).

  The properties of the ceramic film C differ depending on the type of material constituting the ceramic film C. For example, when α alumina fine particles are used as the constituent material of the ceramic film C, the ceramic film C has the electromechanical characteristics shown in the following table.

In general, the electromechanical properties of a ceramic film formed through a sintering process are as follows: Vickers hardness: 1400-2000 Hv, Young's modulus: 350-380 GPa, dielectric breakdown strength: 10 kV / mm or more, volume resistivity: 1.5 × 10 ¹⁵ Ω · cm, dielectric constant: 9.9 to 10ε. In view of this, the ceramic film C formed on the outer ring, the inner ring and / or the ball of the rolling bearing according to the embodiment of the present invention is equal to or more than the electromechanical characteristics of the ceramic film formed through the sintering process. You can say that. In addition, since the ceramic film C has no pores (pores), the film surface has high density.

Table 2 shows an example showing that the ceramic film formed by the aerosol deposition method has high density. Table 2 compares the crystallites and grain boundary phases of the ceramic film, and compares the case of using the aerosol deposition method with the case of using the sintering method (conventional method).

  As shown in Table 2, when the ceramic film is formed by the aerosol deposition method, the denseness of the film is remarkably improved as compared with the case of forming by the sintering method (conventional method). .

  Examples of the material of the outer ring 10 and the inner ring 12 include bearing steel and martensitic stainless steel.

  Examples of the rolling element material include bearing steel, martensitic stainless steel, and ceramics.

  Next, a method for forming the ceramic film C will be described. 4 is a partial sectional view showing the raceway surface 11 of the outer ring 10 and the raceway surface 13 of the inner ring 12 in FIG. 5A is a view for explaining a state in which the ceramic film C is formed on the raceway surface 11 provided on the outer ring 10, and FIG. 5B is a view for explaining a state in which the ceramic film C is formed on the raceway surface 13 provided on the inner ring 12. It is a figure to do.

  The ceramic film is formed by an aerosol deposition method. The aerosol deposition method is a method in which ceramic fine particles are jetted onto a substrate at a high speed and a film is formed by impact that collides with the substrate. By this method, a ceramic film can be formed at room temperature.

  That is, as shown in FIG. 5, an aerosol in which ceramic fine particles such as aluminum oxide are dispersed in a gas is conveyed, and the raceway surface 11 of the outer ring 10 (see FIG. 5A) and the raceway surface 13 of the inner ring 12 (see FIG. 5). 5b) (see arrows in FIG. 5) to produce fine fragment particles in which the primary particles of the ceramic fine particles are crushed, and the fine fragment particles are bonded to the track surfaces 11 and 13 or A dense ceramic film C can be formed without firing by joining the fine fragment particles.

  The speed of the ceramic fine particles in the aerosol deposition method used in the present invention is preferably 300 to 1000 m / sec. The average particle size of the ceramic fine particles is preferably 10 to 200 nm.

  6A is a view for explaining a state in which a ceramic film is formed on the inner peripheral surface (including the raceway surface 11) of the outer ring 10, and FIG. 6B is a diagram illustrating a ceramic film C on the outer peripheral surface of the inner ring 12 (including the raceway surface 13). It is a figure explaining a mode that it forms. As shown in FIG. 6, the ceramic film C may be formed not only on the raceway surfaces 11 and 13 but also on the entire inner peripheral surface including the raceway surface 11 of the outer ring 10 and the entire outer peripheral surface including the raceway surface 13 of the inner ring 12. Good.

  FIG. 7 is a diagram for explaining a state in which the ceramic film C is formed on the balls 14 as rolling elements. Even when the ceramic film C is formed on the balls 14, the ceramic film C can be formed in the same manner as described above.

  The film thickness of the formed ceramic film C is appropriately changed according to the purpose and application of the rolling bearings 1 to 3, but is generally preferably 0.5 μm to 1000 μm.

  Examples of the ceramic fine particles as the material of the ceramic film include silicon nitride, silicon carbide, zirconia and the like in addition to the above aluminum oxide.

  For details of the aerosol deposition method, the fine particle beam deposition method described in JP-A-2002-348677 can be referred to. The fine particle beam deposition method is also called an aerosol deposition method.

  After the formation of the ceramic film C, smoothness on the order of several nanometers can be obtained by performing simple grinding on the film surface of the ceramic film C. Thereby, the acoustic characteristics of the rolling bearings 1 to 3 can be improved. As a grinding method, a conventionally known grinding method can be used.

  As mentioned above, although embodiment of this invention was described to the example of the ball bearing, this invention is not limited to this, For example, a roller bearing may be sufficient.

It is a fragmentary sectional view of the rolling bearing which concerns on the 1st Embodiment of this invention. It is a fragmentary sectional view of the rolling bearing 2 which concerns on the 2nd Embodiment of this invention. It is a fragmentary sectional view of the rolling bearing 3 which concerns on the 3rd Embodiment of this invention. FIG. 3 is a partial sectional view showing a raceway surface 11 of the outer ring 10 and a raceway surface 13 of the inner ring 12 of FIG. 2. (A) The figure explaining a mode that the ceramic film C is formed in the track surface 11 provided in the outer ring | wheel 10, and (b) The figure explaining a mode that the ceramic film C is formed in the track surface 13 provided in the inner ring | wheel 12. is there. (A) The figure explaining a mode that a ceramic film is formed in the inner peripheral surface (including the track surface 11) of the outer ring 10, and (b) The ceramic film C is formed on the outer peripheral surface (including the track surface 13) of the inner ring 12. It is a figure explaining a mode. It is a figure explaining a mode that the ceramic film C is formed in the ball | bowl 14 as a rolling element.

Explanation of symbols

1-3: Rolling bearing, 10: Outer ring, 12: Inner ring, 11 and 13: Raceway surface, 14: Ball, 16: Cage, C: Ceramic film

Claims (9)

A rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring,
(A) A rolling bearing, wherein a ceramic film is formed on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring and / or (B) the rolling element by an aerosol deposition method.   The rolling bearing according to claim 1, wherein the ceramic film is formed on a raceway surface provided on an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring.   3. The rolling bearing according to claim 1, wherein the surface of the ceramic film is cut.   The rolling bearing according to any one of claims 1 to 3, wherein the outer ring and the inner ring are made of bearing steel or martensitic stainless steel.   5. The rolling bearing according to claim 1, wherein the rolling element is made of any one of bearing steel, martensitic stainless steel, and ceramics. A method of manufacturing a rolling bearing comprising an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring,
(A) A ceramic film is formed on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring and / or (B) the rolling element by an aerosol deposition method.   The method for manufacturing a rolling bearing according to claim 6, wherein a speed of the ceramic fine particles in the aerosol deposition method is 300 to 1000 m / sec.   8. The method of manufacturing a rolling bearing according to claim 7, wherein the ceramic fine particles have an average particle diameter of 10 to 200 nm.   The method for manufacturing a rolling bearing according to claim 6, wherein the ceramic film has a thickness of 0.5 μm to 1000 μm.

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