JP2007132382A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exert conducting performance by improving conductive grease even in application for high speed. <P>SOLUTION: Each test result is put in order according to an oil film parameter Λ to thereby permit application to each condition of bearings other than the tested bearings. By using the conductive grease according to the present invention, it can be judged by the graph that the conductive performance can be improved more than is exhibited in a region of a particularly large Λ (to Λ=22, 6 in the embodiment) by the conventional conductive grease. The higher the revolution speed, the smaller the load, and the lower the temperature (the higher the lubricating grease viscosity), Λ becomes larger. That is, the conductive grease according to the present invention can be stated to be effective in a high-speed field the present invention is applied to. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing having improved countermeasures against static electricity, contamination, and radio noise in, for example, devices used at high speeds for copying machines and copying machines.

  Rolling bearings filled with conductive grease are used in the following applications.

(1) Countermeasures against static electricity (explosion-proof applications)
Oil refineries, petroleum product production factories, paint factories, etc. vaporize oil, and depending on the steam and temperature, there is a risk of explosion or ignition even with slight static sparks. Anti-static rolling bearings used for rotating parts used in such hazardous environments. Other uses such as explosion-proof motors and explosion-proof cameras.

(2) Measures against static electricity (contamination measures)
Rolling bearings used for applications that require countermeasures against contamination due to static electricity in clean processes of semiconductor manufacturing plants and liquid crystal glass substrate conveyors.

(3) Countermeasures against radio noise Rolling bearings for machines that require countermeasures against radio noise such as electric motors.

By the way, conventional conductive grease-filled bearings are often used for the purpose of improving the image quality of copiers and printers, and the usage environment thereof is a very low-speed application with a rotational speed of 30 to 300 min ⁻¹ . .

However, when a normal conductive bearing is used in a relatively high speed region of 300 to 50,000 min ⁻¹ , the oil film between the ball and the race surface becomes thicker as the rotational speed becomes higher, and there is a problem that the conductive performance deteriorates. It was.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a rolling bearing that can exhibit conductive performance even in high-speed applications by improving conductive grease.

In order to achieve the above object, the rolling bearing according to the present invention is a rolling bearing encapsulating conductive grease having high conductive performance even at high speed rotation.
The composition of the conductive grease is:
Conductive agent: 10% to 20% carbon black Base oil: PAO, mineral oil, poly-alpha olefin, ester oil, ether oil, polyglycol oil, fluorine oil, mixed oil of these, etc. However, bearing use environment , Thickener: 2 to 10% lithium soap or urea compound, except for fluorine oil, etc. Carbon black may serve as a thickener as it is. Additive: Zn-DTP , Mo-DTP, Ni-DTC, Mo-DTC, etc., which are mixed alone or in a mixture of 1 to 5%.

Preferably, the bearing type of the rolling bearing is:
Deep groove ball bearing (open, contact seal, non-contact seal),
Thin bearings,
Bearing with retaining ring,
Either a bearing with a heat insulating bush or a bearing with a flange.

  Further, preferably, by increasing the number of balls or applying a preload to the bearing, the number of contacts between the balls and the race surface is increased, and further conductivity is improved.

  Furthermore, preferably, a double seal with three or more bearing seals is used.

  Further, preferably, as a rust-proof bearing, SUS material is used as a bearing material, or plating corrosion treatment such as electroless nickel plating is applied to the inner ring and the outer ring.

  According to the present invention, even when the oil film between the ball and the race surface is thickened by high-speed rotation, the structure of carbon black in the conductive grease is not interrupted, and the grease that can maintain the conductive performance is used. In addition, grease that suppresses the generation of an insulating film (oxide film) on the race surface and the surface of the ball, which is harmful to conductivity, is used by adding a metal additive.

  Therefore, it is possible to take measures against static electricity, contamination, and radio noise in devices used at high speed.

  As a result, in a hazardous environment such as an oil refining factory, petroleum product production factory, painting factory, etc., static electricity generated at the outer peripheral part of the bearing can be released, which is an explosion-proof measure.

  In addition, it is possible to take measures against contamination caused by static electricity in a clean environment of a semiconductor manufacturing plant, a liquid crystal glass substrate transfer conveyor, and the like.

  Furthermore, it can also be applied as a countermeasure against radio noise of an electric motor or the like.

  Hereinafter, a rolling bearing according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
The rolling bearing according to the present embodiment is a rolling bearing encapsulating conductive grease having high conductivity performance even at high speed rotation.
The composition of the conductive grease is:
Conductive agent: 10% to 20% carbon black Base oil: PAO, mineral oil, poly-alpha olefin, ester oil, ether oil, polyglycol oil, fluorine oil, mixed oil of these, etc. However, bearing use environment , Thickener: 2 to 10% lithium soap or urea compound, except for fluorine oil, etc. Carbon black may serve as a thickener as it is. Additive: Zn-DTP , Mo-DTP, Ni-DTC, Mo-DTC, etc., which are mixed alone or in a mixture of 1 to 5%.

  According to this embodiment, even when the oil film between the ball and the race surface is thickened by high-speed rotation, the structure of carbon black in the conductive grease is not interrupted, and the grease that can maintain the conductive performance is used. . In addition, grease that suppresses the generation of an insulating film (oxide film) on the race surface and the surface of the ball, which is harmful to conductivity, is used by adding a metal additive.

  Therefore, it is possible to take measures against static electricity, contamination, and radio noise in devices used at high speed. As a result, in a hazardous environment such as an oil refining factory, petroleum product production factory, painting factory, etc., static electricity generated at the outer peripheral part of the bearing can be released, which is an explosion-proof measure. In addition, it is possible to take measures against contamination caused by static electricity in a clean environment of a semiconductor manufacturing plant, a liquid crystal glass substrate transfer conveyor, and the like. Furthermore, it can also be applied as a countermeasure against radio noise of an electric motor or the like.

  Preferably, the bearing type of the rolling bearing is any of a deep groove ball bearing (open, contact seal, non-contact seal), a thin bearing, a bearing with a retaining ring, a bearing with a heat insulating bush, and a bearing with a flange. is there.

  Further, preferably, by increasing the number of balls or applying a preload to the bearing, the number of contacts between the balls and the race surface is increased and further conductivity is improved.

  Further, preferably, as a rust-proof bearing, SUS material is used as a bearing material, or plating corrosion treatment such as electroless nickel plating is applied to the inner ring and the outer ring.

(Example corresponding to the first embodiment)
An example corresponding to the first embodiment will be described below.

  The test bearing used an inner diameter of φ30, an outer diameter of φ42, and a width of 4, under the conditions of a temperature of 40 ° C. and a radial load of 15 kgf.

  By arranging each test result by the oil film parameter Λ, it is possible to adapt to each condition of the bearing other than the test bearing.

で表される式であり、ｈは、軸受の回転数、荷重、温度、潤滑油の粘度により定まる。 Oil film parameter is

Where h is determined by the number of rotations of the bearing, the load, the temperature, and the viscosity of the lubricating oil.

  By using the conductive grease according to the present invention, it is possible to improve the conductive performance more than the conventional conductive grease, particularly in a region where Λ is large (in the embodiment, up to Λ = 22, 6). This can be determined from FIG. FIG. 1 relates to the first embodiment of the present invention and is a graph showing the relationship between the resistance value between the bearing inner and outer rings and the oil film parameter.

  Λ increases as the rotational speed increases, the load decreases, the temperature decreases (the lubricating oil viscosity increases), that is, it can be said that the Λ is effective in the field of high-speed rotation that is an application of the present invention. .

  When the conductive performance that does not cause a problem in actual use is assumed to be lower than 100 kΩ, Λ satisfying less than 100 kQ is a condition of Λ = 14 or less from FIG.

例えば、軸受６２０６を、４０°Ｃ、ラジアル荷重５０ｋｇｆで使用した場合、最大４８００ｍｉｎ^−１の使用回転数まで、導電性１００ｋΩ未満を満たすことができることを表す。 Table 1 shows an example of adapting to other bearings to satisfy this Λ.

For example, when the bearing 6206 is used at 40 ° C. and a radial load of 50 kgf, it indicates that the conductivity can be less than 100 kΩ up to a maximum number of rotations of 4800 min ⁻¹ .

評価結果：軸受の内外輪間の抵抗値を測定する。結果を表２に示す。 Example:
Evaluation bearing: inner diameter φ30, outer diameter φ42, width 4
Evaluation conditions: normal temperature, radial load 15 kgf
Evaluation bearing specifications:
Normal grease: Lithium general-purpose grease Conventional conductive grease: Car pump rack 5%
Conductive grease according to the present invention: carbon black 18%, thickener Li 3%, additive Mo-DTPI%

Evaluation result: The resistance value between the inner and outer rings of the bearing is measured. The results are shown in Table 2.

(Second Embodiment)
Fig.2 (a) is sectional drawing of the rolling bearing which concerns on 2nd Embodiment of this invention. In the present embodiment, the bearing seal is generally an overlapping seal with three or more. Thereby, the leakage of conductive grease is reduced and the conductive performance is further improved.

  In FIG. 2A, a ball 3 is interposed between an outer ring 1 and an inner ring 2 so as to be able to roll, and the ball 3 is maintained at a predetermined interval by a cage 4. .

  External seal members 11 are attached to the end portions on both sides of the outer and inner rings 1 and 2. The outer seal member 11 is fixed to the outer ring 1 side and is an iron seal, but may be a rubber seal.

  An inner seal member 12 is mounted on the inner side of the outer seal 11. The inner seal member 12 is fixed to the outer ring 1 side, and a conductive effect can be obtained by using an iron seal.

  FIG. 2B is a cross-sectional view of a rolling bearing according to a modification of the second embodiment of the present invention, and FIG. 2C is a side view of the internal seal member shown in FIG.

  2B and 2C, external seal members 11 are attached to the end portions on both sides of the outer and inner rings 1 and 2, respectively. The outer seal member 11 is fixed to the outer ring 1 side and is an iron seal, but may be a rubber seal.

  An inner seal member 13 is mounted on the inner side of the outer seal 11. The inner seal member 13 is fixed to the inner ring 2 side, and is an iron C-shaped seal as shown in FIG.

  From the above, the sealing function can be enhanced. Further, the inner seal member 12 and the inner seal member 13 (C-shaped seal) are conductive materials and are electrically connected to the inner ring 2 or the outer ring 1 through conductive grease. This makes it possible to improve the conductive performance.

  Furthermore, since the sealing function is strengthened, the amount of conductive grease filled can be increased, the conductive effect is improved, and the bearing durability at high speed is also improved.

  Furthermore, since the sealing function is strengthened, grease scattering to the outside can be reduced even at high speeds.

  This embodiment is an example, and the number of seals can be three or more. Further, the internal seal member 12 and the internal seal member 13 (C-shaped seal) can be freely combined.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

It is a graph which concerns on 1st Embodiment of this invention and shows the relationship between the resistance value between bearing inner and outer rings, and an oil film parameter. (A) is sectional drawing of the rolling bearing which concerns on 2nd Embodiment of this invention. (B) is sectional drawing of the rolling bearing which concerns on the modification of 2nd Embodiment of this invention, (c) is a side view of the internal seal member shown to (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 3 Ball 4 Cage 11 External seal member 12, 13 Internal seal member

Claims (5)

In rolling bearings filled with conductive grease that has high conductive performance even at high speed rotation,
The composition of the conductive grease is:
Conductive agent: 10% to 20% carbon black Base oil: PAO, mineral oil, poly-alpha olefin, ester oil, ether oil, polyglycol oil, fluorine oil, mixed oil of these, etc. However, bearing use environment , Thickener: 2 to 10% lithium soap or urea compound, except for fluorine oil, etc. Carbon black may serve as a thickener as it is. Additive: Zn-DTP , Mo-DTP, Ni-DTC, Mo-DTC, etc., which are mixed alone or in a mixture of 1 to 5%. The bearing type of the rolling bearing is:
Deep groove ball bearing (open, contact seal, non-contact seal),
Thin bearings,
Bearing with retaining ring,
The rolling bearing according to claim 1, wherein the rolling bearing is one of a bearing with a heat insulating bush and a bearing with a flange.   The rolling bearing according to claim 1 or 2, wherein the number of balls is increased or a preload is applied to the bearing to increase the number of contacts between the balls and the race surface, thereby further improving the electrical conductivity.   The rolling bearing according to any one of claims 1 to 3, wherein the bearing seal is a double seal including three or more bearing seals.   5. The rust preventive bearing according to claim 1, wherein an SUS material is used as a bearing material, or an inner ring and an outer ring are subjected to plating corrosion resistance treatment such as electroless nickel plating. Rolling bearing.

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