JP2010190394A - Rolli bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent creep and generation of abnormal noise for a long period and maintain stable rotation in a rolling bearing in which the shaft of a rotary member is fitted in or on the raceway ring of one of the an inner and an outer ring through clearance fitting. <P>SOLUTION: This rolling bearing retains a plurality of rolling elements between the inner ring and the outer ring and supports the shaft of the rotary member by fitting it on the inner diameter surface of the inner ring or on the outer diameter surface of the outer ring through clearance fitting. Coating composed of solid lubricant is formed by shot blasting at least on the inner diameter surface of the inner ring or the outer diameter surface of the outer ring in or on which the shaft of the rotary member is fitted. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rolling bearing in which a shaft portion of a rotating member is fitted to one of the inner and outer races by a clearance fit.

  Rotating members such as fixing rollers and pressure rollers incorporated in office machines such as copiers and printers have their shaft parts (shafts) of the inner and outer rings of rolling bearings due to problems of assembly due to downsizing and simplification of the structure. Many of them are fitted to one of the race rings by a clearance fit (loose fit). For this reason, depending on use conditions, there is a possibility that creep may occur between the shaft portion fitted by clearance fitting and the race.

  There is also a problem that abnormal noise is generated in the fitting portion during printing. In recent years, in particular, the fixing unit of the fixing device is required to have a function of fixing toner to paper and high-quality printing faster as the printing speed increases and the image quality increases. When fretting occurs on the inner diameter and the shaft surface, abnormal noise at the fitting portion is more likely to occur.

  Conventionally, grease has been applied to the fitting part to prevent wear and noise from the fitting due to creep. Due to problems such as contamination, a coating made of an oxide film or a solid lubricant may be formed on the race. Moreover, since there is a problem of charging in office machines such as copying machines and printers, it is preferable that the coating has conductivity. For example, in Patent Document 1, a nickel-polytetrafluoroethylene composite coating or a graphite coating is formed. .

Japanese Patent Laid-Open No. 2008-8852

  In general, the accuracy grade of rolling bearings generally used in office equipment such as copying machines and printers is JIS0 class, and the tolerance of the inner diameter of a rolling bearing having an inner diameter of φ30 mm is 0 to −10 μm. However, in Patent Document 1, the film is formed with a thickness of 2 to 10 μm in consideration of the durability of the coating, and the film is allowed to exceed the inner diameter dimension tolerance, and the shaft is inserted into the inner ring. It becomes difficult to do. Also, the film forming method is electroplating, electroless plating, vacuum deposition, ion plating, sputtering, etc., physical vapor deposition, chemical vapor deposition, dipping, coating, spray spraying, and the adhesive strength of the film is not necessarily sufficient.

  The present invention has been made in view of such a situation, and prevents creep and abnormal noise for a long period of time in a rolling bearing in which the shaft portion of the rotating member is fitted to one of the inner and outer rings by clearance fitting. The purpose is to maintain a stable rotation.

In order to solve the above problems, the present invention provides the following rolling bearing.
(1) A rolling bearing that holds a plurality of rolling elements between an inner ring and an outer ring, and supports the shaft portion of the rotating member by fitting the inner ring surface of the inner ring or the outer diameter surface of the outer ring with a clearance fit. A rolling bearing characterized in that a coating made of a solid lubricant is formed by shot blasting on at least the inner diameter surface of the inner ring to which the shaft portion of the rotating member is fitted or the outer diameter surface of the outer ring.
(2) The rolling bearing according to the above (1), wherein the solid lubricant is a mixture of 5% by mass to less than 80% by mass of zinc and 20% by mass to 95% by mass of tin.
(3) The rolling bearing according to (1) or (2) above, wherein the film thickness is 0.1 μm or more and less than 2 μm.

  In the rolling bearing according to the present invention, a coating made of a solid lubricant for preventing wear and noise due to creep is formed by the shot blasting method, so that the coating has high adhesive strength and is excellent in durability. Further, since the film thickness is less than 2 μm, when it is applied to a general rolling bearing for office equipment such as a copying machine or a printer, the inner diameter allowable dimensional difference is satisfied and the rotational stability is not impaired.

It is sectional drawing which shows an example of the rolling bearing which concerns on this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  For example, a deep groove ball bearing 1 as shown in FIG. 1 can be exemplified as a rolling bearing in which the shaft portion of the rotating member is fitted to one of the race rings of the inner and outer rings by clearance fitting. In the illustrated deep groove ball bearing 1, an inner ring 2 having an inner ring rolling surface 2a on an outer peripheral surface and an outer ring 3 having an outer ring rolling surface 3a on an inner peripheral surface are arranged concentrically, and the inner ring rolling surface 2a and the outer ring A plurality of balls 4 are arranged between the rolling surface 3a and the bearing space formed by the inner ring 2, the outer ring 3 and the balls 4 is filled with lubricating grease 7 and sealed with a seal member 6. ing. The deep groove ball bearing 1 is fitted with the inner ring 2 by a shaft portion 10 of a rotating member with a clearance fit.

  In the present invention, the coating 8 made of a solid lubricant is formed on the inner diameter surface 2b of the inner ring 2 by shot blasting. There is no particular limitation on the solid lubricant, but it has a corrosion resistance as well as a lubricating action. Further, since it is easy to be charged in a copying machine or a printer, it is preferable to be able to impart conductivity, so a mixture of zinc and tin. Is preferred. In particular, zinc is 5% by mass or more and less than 80% by mass, more preferably 50% by mass or less, and a mixture of the remaining tin is preferable.

  In order to form the coating 8, zinc particles and tin particles may be sprayed on the inner peripheral surface 2b of the inner ring 2 at the above ratio using a shot blasting apparatus. In that case, the zinc particles may be shot blasted after shot blasting, the tin particles may be shot blasted and then zinc particles may be shot blasted, or the zinc particles and tin particles are mixed and shot. Blasting may be performed, or particles made of an alloy of zinc and tin may be shot blasting. Thereby, a two-layer structure of zinc and tin, an alloy structure, a composite structure, a sea-island structure, or a film in which these structures are mixed is formed. The two-layer structure is a structure composed of a zinc underlayer and a tin surface layer, or a tin underlayer and a zinc surface layer. The alloy structure is a structure in which almost the entire coating is made of an alloy of zinc and tin. The composite structure is a structure in which almost the entire coating is composed of a mixture of zinc and tin, and the ratio of zinc or tin from the base material (inner peripheral surface 2b of the inner ring 2) side to the surface side. Is a structure that gradually changes. The sea-island structure is a structure in which tin is distributed in an island shape in a matrix made of zinc, or zinc is distributed in an island shape in a matrix made of tin. An example in which these structures are mixed includes a three-layer structure including a zinc underlayer, an intermediate alloy layer, and a tin surface layer.

  In addition, there is no restriction | limiting in the particle size of a zinc particle and a tin particle, However, When the film-forming efficiency and the property of the coating film 8 obtained are considered, it is preferable that it is 1.0-1.5 micrometers.

  The thickness of the coating 8 is preferably 0.1 μm or more and less than 2 μm, and more preferably 1.0 to 1.5 μm. If the film thickness is less than 0.1 μm, it cannot be said that the durability is sufficient. Further, if it is attempted to form such a thin film, the film 8 may not be partially formed. Further, when the film thickness is 2 μm or more, the inner diameter dimension tolerance is exceeded, which may hinder the rotation of the shaft portion 10. In the present invention, since the coating 8 is formed by shot blasting, even such a thin film has a large adhesive strength and sufficient durability.

  Hereinafter, the present invention will be further described with reference to test examples, but the present invention is not limited thereto.

(Test 1)
The same amount of zinc particles and tin particles were shot blasted onto the SUJ2 outer ring for the ball bearing 6806 to form a zinc-tin coating having a thickness of 0.1 μm, 0.5 μm, 2 μm, and 5 μm. Each outer ring was kept in a high-temperature and high-humidity environment at a temperature of 70 ° C. and a humidity of 90% for 720 hours, and then the presence or absence of rust was examined. In any case, the occurrence of rust was not observed.

  For comparison, when the outer ring made of SUS440C was kept in the same high-temperature and high-humidity environment, spot-like rust was generated in 168 hours.

(Test 2)
Zinc particles and tin particles are mixed at a ratio of 2: 8, 4: 6, 5: 5, and 8: 2 to the SUJ2 outer ring for the ball bearing 6806, shot blasted, and thickened. A zinc-tin coating having a thickness of 1.0 μm was formed. Moreover, the outer ring made from SUS440C was prepared for the comparison. Then, salt water was sprayed on each outer ring to observe the occurrence of rust. The results are shown in Table 1.

  As shown in Table 1, it can be seen that the formation of rust can be suppressed by forming a zinc-tin coating having a zinc ratio of less than 80% by mass, particularly 50% by mass or less.

(Test 3)
It was 0.31 when the friction coefficient of SUJ2 board was measured. Further, when the coefficient of friction of the film forming surface of the outer ring of Example 2 of Test 2 was measured, it was 0.19, and the friction was reduced by about 40%.

(Test 4)
Zinc particles and tin particles were mixed at a ratio of 4: 6 (zinc: tin) ratio to a SUJ2 outer ring for the ball bearing 608 and shot blasted to form a zinc-tin coating having a thickness of 1.0 μm. . Moreover, the outer ring made from SUS440C was prepared for the comparison. And creep resistance was measured by unbalance load 0.0183N. The test was performed three times, and the average value was taken as the creep resistance, which was 16N when the outer ring made of SUS440 was used, whereas it was 24N when the outer ring formed with the zinc-tin coating was used. About 45% improvement.

  From the above test results, it was confirmed that by forming a zinc-tin coating film by shot blasting according to the present invention, rust hardly occurs and creep resistance can be improved.

DESCRIPTION OF SYMBOLS 1 Deep groove ball bearing 2 Inner ring 2a Inner ring rolling surface 2b Inner surface 3 Outer ring 3a Outer ring rolling surface 4 Ball 5 Cage 6 Seal member 7 Grease 8 Solid lubricant lubricant coating 10 Rotating member shaft

Claims (3)

A rolling bearing that holds a plurality of rolling elements between an inner ring and an outer ring, and supports the shaft portion of the rotating member by fitting the inner ring surface of the inner ring or the outer diameter surface of the outer ring with a clearance fit,
A rolling bearing characterized in that a coating made of a solid lubricant is formed by shot blasting on at least an inner diameter surface of an inner ring to which a shaft portion of a rotating member is fitted or an outer diameter surface of an outer ring.   The rolling bearing according to claim 1, wherein the solid lubricant is a mixture of 5% by mass or more and less than 80% by mass of zinc and 20% by mass or more and 95% by mass or less of tin.   The rolling bearing according to claim 1 or 2, wherein the film has a thickness of 0.1 µm or more and less than 2 µm.

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