JP2009232570A - Rolling bearing for motor and seal member for motor bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing for motor and a seal member for motor bearing, which maintain the effect of auxiliary agent for grease for a long time and extend life of a motor in recent use. <P>SOLUTION: The rolling bearing is provided with: an inner ring 2, an outer ring 3, a plurality of rolling bodies 4 installed between the inner and outer rings, a holder 5 holding the rolling bodies 4, and the seal members 6 arranged in both end openings in an axial direction of the inner ring 2 and the outer ring 3. In the rolling bearing 1 for the motor, which is lubricated by grease 7 filled into the space in the bearing, which is constituted of the inner ring 2, the outer ring 3, the holder 5 and the seal members 6, a mixture 6a of auxiliary agent for grease and resin is fixed to a space-side surface in the bearing of the seal member 6, one of members constituting the space in the bearing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a grease-lubricated motor rolling bearing, and more particularly to a motor rolling bearing for industrial machinery and electrical equipment, and a motor bearing seal member used for the rolling bearing.

  In recent years, in general-purpose motors such as AC motors and DC motors, miniaturization of motors has progressed and bearings tend to be operated under higher surface pressure. Electric motors for industrial machinery such as servo motors, starter motors for automobiles, electric power steering motors, tilt motors for steering adjustment, blower motors, wiper motors, power window motors, and other motors for electrical equipment start-up and rapid acceleration operation -Since high-speed operation, rapid deceleration operation, and sudden stop are frequently repeated, the slip generated in the rolling bearing for the motor increases accordingly. As the usage conditions become severe in this way, specific peeling with a change in white structure occurs at an early stage on the rolling surface of the rolling bearing for the motor, so that the rolling bearing for the motor can be stably operated for a long period of time. Durability and reliability are required.

Conventionally, ball bearings that have a seal and are used for grease lubrication have been widely used to form various types of rotation support members. For example, in a radial ball bearing having a crown-shaped cage as a cage and having seals on both sides, the axial center line of the ball is closer to the claw of the crown-shaped cage than the axial center lines of the inner ring and the outer ring There is known a radial ball bearing (see Patent Document 1) characterized in that it is deviated.
In addition, regarding ball bearings that have a shield and are used for grease lubrication, as a technique for improving lubricity and extending the service life, for example, it is known to use grease having excellent heat resistance (Patent Document) 2).

However, in the rolling bearings described in Patent Document 1 and Patent Document 2, there is a limit to the amount of grease that can be filled in the bearing internal space, so that it is possible to further extend the life in the recent motor applications described above. It was difficult.
JP 2002-130305 A JP 2004-352858 A

  The present invention has been made to cope with such problems, and it is possible to maintain the effectiveness of the auxiliary agent for grease for a long time, and to provide a rolling bearing for motor that can improve the life even in recent motor applications. It aims at providing the sealing member for motor bearings.

  The motor rolling bearing of the present invention is a motor rolling bearing that supports a rotor of the motor, and the motor rolling bearing includes an inner ring, an outer ring, and a plurality of rolling elements interposed between the inner and outer rings. A bearing configured to include the inner ring, the outer ring, the cage, and the seal member, each of which includes a cage that holds the rolling element and a seal member that is provided at both axial openings of the inner ring and the outer ring. In the at least one member of the member constituting the bearing inner space, which is lubricated by the grease sealed in the inner space, the grease on the surface in the bearing inner space other than the sliding surface with the rolling element of the member An auxiliary agent for use is fixed. Also, the grease auxiliary agent is fixed to the bearing inner space side surface of the seal member.

  The auxiliary agent for grease in the present invention is one in which its components are directly dissolved in the grease (additive), or gas is generated to reduce the oxygen concentration in the bearing inner space, thereby reducing the oxidation of the grease. Includes indirectly assisting grease such as preventing.

  The auxiliary agent for grease is fixed in a state of being contained in a resin. The resin is an epoxy resin.

  When the auxiliary agent for grease is fixed in a state of being contained in the resin, the proportion of the auxiliary agent is 10% by weight or more based on the total of the auxiliary agent and the resin. .

  The auxiliary agent for grease is a foaming agent or an antioxidant. Further, the antioxidant is an amine-based antioxidant.

  The foaming agent is at least one selected from organic foaming agents. The organic foaming agent is azodicarbonamide.

  The seal member for a motor bearing according to the present invention is characterized in that the above-mentioned auxiliary agent for grease is fixed.

  According to the rolling bearing for a motor having the above-described configuration in the present invention, when an additive for grease, such as an antioxidant, is fixed as an auxiliary agent for grease on the surface in the bearing inner space side of the seal member, the additive Comes into contact with the grease sealed in the bearing, so that the additive component dissolves in the grease. For this reason, the efficacy as an additive component can be continuously imparted to the grease, and the efficacy due to the additive can be maintained for a long time.

  By making the auxiliary agent for grease into a mixture containing the auxiliary agent in a resin, it can be easily fixed to each surface by adhering and applying the mixture.

  When a foaming agent is used as the auxiliary agent for the grease, the foaming agent can release an inert gas at a high temperature to reduce the oxygen concentration in the bearing inner space. For this reason, the oxidative deterioration of grease can be suppressed and the bearing can be used for a long time.

  The seal member for a motor bearing according to the present invention is formed by fixing the above-mentioned auxiliary agent for grease. Therefore, it is possible to prevent oxidative deterioration of grease sealed in the rolling bearing for motor, and the rolling bearing for motor using the seal member. Can extend the service life.

Embodiments of the present invention will be described in detail with reference to the drawings. An example of a rolling bearing for a motor that supports the rotor of the motor is shown in FIG. FIG. 1 is a cross-sectional view of a deep groove ball bearing in which grease is enclosed.
In the deep groove ball bearing 1, an inner ring 2 having an inner ring rolling surface 2a on the outer peripheral surface and an outer ring 3 having an outer ring rolling surface 3a on the inner peripheral surface are arranged concentrically, and the inner ring rolling surface 2a and the outer ring rolling surface 3a. A plurality of rolling elements 4 are arranged between the two. A cage 5 that holds the plurality of rolling elements 4 is provided. In addition, seal members 6 fixed to the outer ring 3 and the like are provided in the axially opposite end openings 8a and 8b of the inner ring 2 and the outer ring 3, respectively. The deep groove ball bearing 1 is lubricated by grease 7 sealed in a bearing inner space constituted by an inner ring 2, an outer ring 3, a cage 5 and a seal member 6.
In this embodiment, a mixture 6a of an auxiliary agent for grease and a resin is fixed to the surface of the seal member 6 on the bearing inner space side as one member constituting the bearing inner space.

  An example of a motor using the rolling bearing for motor of the present invention is shown in FIG. FIG. 2 is a sectional view of the structure of the motor. The motor includes a stator 10 made of a magnet for a motor disposed on the inner peripheral wall of the jacket 9, a rotor 13 around which a winding 12 fixed to the rotating shaft 11 is wound, and a commutator fixed to the rotating shaft 11. 14, a brush holder 15 disposed on an end frame 17 supported by the jacket 9, and a brush 16 accommodated in the brush holder 15. The rotating shaft 11 is rotatably supported by the jacket 9 by the deep groove ball bearing 1 and a support structure for the bearing 1. The bearing 1 is a rolling bearing for a motor according to the present invention.

  When a grease additive such as an antioxidant is used as an auxiliary agent for grease, the grease 7 sealed in the bearing inner space is subjected to an external force such as a centrifugal force caused by the rotation of the deep groove ball bearing 1 to be a bearing. When moving in the inner space, it contacts with the mixture 6a fixed to the bearing inner space side surface of the seal member 6 to receive the additive for grease, and the outer ring raceway 3a of the ball 4 and the outer ring 3 and the inner ring raceway of the inner ring 2 It is used for lubrication between 2a and between the ball 4 and the cage 5.

The grease 7 incorporating the additive for grease circulates in the bearing, and even if the additive in the grease is consumed on each sliding surface, the additive dissolves into the grease 7 and repeats the predetermined concentration even when the additive in the grease is consumed. Thus, the efficacy of the additive can be maintained for a long time.
In addition, even if it is a grease additive that cannot be blended at a high concentration because of its compatibility with the grease component, the antioxidant component is gradually supplied to the grease while maintaining compatibility with the grease. On the other hand, as a result, it can mix | blend with high concentration and the effect by this additive can be maintained for a long time.

  When a foaming agent is used as an auxiliary agent for grease, an inert gas is generated from the mixture 6a fixed to the bearing inner space side surface of the seal member 6 and the oxygen concentration in the bearing inner space is reduced. Oxidative deterioration of the grease 7 is suppressed.

As other embodiments of the present invention, as other locations for fixing the auxiliary agent for grease, the surface of the cage 5 (other than the sliding surface with the ball), the outer diameter surface of the inner ring 2 (other than the raceway surface), An inner diameter surface (other than the raceway surface) of the outer ring 3 is exemplified. These may be fixed in one place or a plurality of places.
The present invention is not limited to these embodiments, and appropriate modifications and improvements can be made. As the seal member 6, there is, for example, a seal reinforced with a steel plate in addition to a steel plate shield, and the seal material may be a synthetic rubber such as nitrile rubber, acrylic rubber, silicon rubber, or fluorine rubber.

The grease encapsulated in the motor rolling bearing of the present invention can be used without particular limitation as long as it is a grease normally used in rolling bearings.
Examples of the base oil constituting the grease include mineral oils such as paraffinic mineral oil and naphthenic mineral oil, polybutene oil, poly-α-olefin (hereinafter referred to as PAO) oil, alkylbenzene oil, alkylnaphthalene oil, and alicyclic compounds. Non-hydrocarbon synthetic oils such as natural fats and oils, polyol ester oils, phosphate ester oils, diester oils, polyglycol oils, silicone oils, polyphenyl ether oils, alkyl diphenyl ether oils, fluorinated oils, etc. Any oil that is generally used as a base oil for lubricating grease, such as synthetic oil, can be used without particular limitation. These base oils may be used alone or in combination of two or more.

  Thickeners include metal soap thickeners such as aluminum soap, lithium soap, sodium soap, composite lithium soap, composite calcium soap, composite aluminum soap, urea compounds such as diurea compounds and polyurea compounds, polytetra Fluorine resin powder such as fluoroethylene resin can be used. These thickeners may be used alone or in combination of two or more.

  In addition, a known additive may be included in the grease to be sealed in the rolling bearing for motor according to the present invention, if necessary. As this additive, for example, viscosity index improvers such as polymethacrylate and polystyrene, solid lubricants such as molybdenum disulfide and graphite, rust preventives such as metal sulfonates and polyhydric alcohol esters, friction reducers such as organic molybdenum, Examples thereof include oily agents such as esters and alcohols, and antiwear agents such as phosphorus compounds. These can be added alone or in combination of two or more. Moreover, the following adjuvant fixed to a bearing member can be previously mix | blended with grease.

  The auxiliary agent for grease fixed to the member constituting the bearing inner space is preferably a foaming agent or an antioxidant.

  Any foaming agent may be used as long as it generates an inert gas during foaming. Preferably, the foaming start temperature is higher than the operating temperature of the bearing. In addition, as an inert gas, nitrogen, a carbon dioxide, etc. are preferable, for example. As the foaming agent that generates such an inert gas, at least one selected from organic foaming agents is used because it is difficult to cause damage such as scratches even if it is mistakenly mixed with the rolling surface of the bearing. preferable. Examples of the organic foaming agent include triazine compounds, hydrazine compounds, tetrazole compounds, azo compounds such as azodicarbonamide, and the like. It is preferable to use azodicarbonamide because of the large amount of gas generated in these organic foaming agents. These foaming agents can be used alone or in admixture of two or more.

  Examples of the antioxidant include phenolic and aromatic amine compounds and alkyldithiophosphates. Examples thereof include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol and amine antioxidants such as p, p′-dioctyldiphenylamine. Examples of the alkyldithiophosphate include zinc alkyldithiophosphate. Of these, amine-based antioxidants are preferably used because of their good solubility in grease base oils. These antioxidants can be used alone or in admixture of two or more.

In the rolling bearing for a motor of the present invention, a method of fixing an auxiliary agent for grease to a member constituting the bearing inner space will be described taking a seal member as an example. As a method of fixing the auxiliary agent for grease on the surface of the seal member inside the bearing, there is no particular limitation.
(1) A method of attaching a resin layer as an adhesive to the surface in the bearing inner space of the seal member, and attaching an auxiliary agent layer to the surface,
(2) A method of laminating and adhering the resin layer and auxiliary agent layer of (1),
(3) A method of adhering a mixture obtained by mixing an auxiliary agent and resin to the bearing inner space side surface of the seal member with an adhesive,
(4) A method of adhering a mixture obtained by mixing an auxiliary agent and a resin as an adhesive to the surface in the bearing space of the seal member;
(5) The method etc. which apply | coat the resin coating composition formed by melt | dissolving an adjuvant in a resin solvent to the bearing inner space side surface of a sealing member can be used.

  When using an additive for grease such as an antioxidant as a grease additive, grease that moves in the bearing space by making the distribution of the additive in the mixture uniform among these methods The method of (3) to (5) is preferable because the additive for grease can be supplied stably. Furthermore, it is particularly preferable to use the method according to (5) in which the additive can be easily fixed to the seal member and is not detached even by the circulation of grease.

  Moreover, also when using a foaming agent as an adjuvant for grease, the method of (3)-(5) which can make distribution of the foaming agent in a mixture uniform is preferable. Furthermore, it is particularly preferable to use the method according to (4) that can easily fix the foaming agent to the sealing member.

  When the auxiliary agent for grease is fixed in a state where it is contained in the resin, the proportion of the auxiliary agent is preferably 10% by weight or more based on the total of the auxiliary agent and the resin. If it is less than 10% by weight, the durability improving effect is poor, which is not preferable.

  The resin used to obtain the mixture with the auxiliary agent for grease is not particularly limited as long as it has both adhesion to sealing members such as steel shields and rubber seals and adhesion to the auxiliary agent for grease. It can be used without. For example, a polyamide resin, a polyethylene resin, a polypropylene resin, an epoxy resin, etc. can be mentioned. Among these, it is preferable to use an epoxy resin because the hardness is stable within the practical use temperature range of the rolling bearing for motor.

Examples 1 to 4
An auxiliary agent for grease shown in Table 1 and a two-pack type epoxy resin (manufactured by Nichiban Co., Ltd .: Araldite AR-S30) were mixed to obtain a resin coating composition. This resin coating composition was applied to the surface of the seal member on the space inside the bearing and dried at 40 ° C. for 24 hours to obtain a seal member on which an auxiliary agent for grease was fixed. This seal member was mounted on both sides of a rolling bearing (bearing dimensions: inner diameter 20 mm, outer diameter 47 mm, width 14 mm) to obtain a bearing test piece. This test piece was subjected to a high-temperature high-speed durability test shown below, and the bearing life time was measured. The results are also shown in Table 1.

<High-temperature high-speed durability test>
The test specimen obtained is filled with 0.7 g of the grease shown in Table 1 and rotated at a rotation speed of 10000 rpm under a bearing outer ring outer diameter temperature of 150 ° C, radial load of 67 N, and axial load of 67 N. Was measured as the bearing life time.

Comparative Example 1 and Comparative Example 3
Apply only two-component epoxy resin (manufactured by Nichiban Co., Ltd .: Araldite AR-S30) to the bearing inner space side surface of the seal member without using an auxiliary agent for grease, and dry it at 40 ° C for 24 hours to fix the epoxy resin. A sealed member was obtained. This seal member was mounted on both sides of a rolling bearing (bearing dimensions: inner diameter 20 mm, outer diameter 47 mm, width 14 mm) to obtain a bearing test piece. This test piece was subjected to the high-temperature high-speed durability test, and the bearing life time was measured. The results are also shown in Table 1.

Comparative Example 2 and Comparative Example 4
A seal member that does not use an auxiliary agent for grease or epoxy resin was mounted on both sides of a rolling bearing (bearing dimensions: inner diameter 20 mm, outer diameter 47 mm, width 14 mm) to obtain a bearing test piece. This test piece was subjected to the high-temperature high-speed durability test, and the bearing life time was measured. The results are also shown in Table 1.

  In Examples 1 to 4 in which the mixture of the grease auxiliary agent and the resin was fixed to the surface in the bearing inner space of the seal member, it was possible to prevent the grease from being oxidized and improve the bearing life. .

  In the rolling bearing for a motor of the present invention, an auxiliary agent such as an antioxidant fixed on the surface of the constituent member can be dissolved in the grease to impart an effect as an additive component to the grease for a long time. The oxygen concentration in the bearing inner space can be lowered by gas generated from the auxiliary agent, etc., and the life of the motor rolling bearing can be extended. For this reason, the rolling bearings for motors of the present invention include general-purpose motors such as AC motors and DC motors, electric motors for industrial machines such as servo motors, automobile starter motors, electric power steering motors, tilt adjustment tilt motors, and blower motors. It can be suitably used as a bearing used in motors for electrical equipment such as wiper motors and power window motors.

It is sectional drawing of the rolling bearing which shows one Embodiment of the rolling bearing for motors of this invention. It is sectional drawing of the structure of a motor.

Explanation of symbols

1 Deep groove ball bearing 2 Inner ring 3 Outer ring 4 Ball (rolling element)
DESCRIPTION OF SYMBOLS 5 Cage 6 Seal member 6a Mixture of auxiliary agent and resin for grease 7 Grease 8a, 8b Opening 9 Jacket 10 Stator 11 Rotating shaft 12 Winding 13 Rotor 14 Commutator 15 Brush holder 16 Brush 17 End frame

Claims (10)

A rolling bearing for a motor that supports a rotor of a motor, the rolling bearing for a motor comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling element And a seal member provided at both ends of the inner ring and the outer ring in the axial direction, and is lubricated by grease sealed in a bearing inner space composed of the inner ring, the outer ring, the cage, and the seal member. Being
In at least one member constituting the bearing inner space, the grease auxiliary agent is fixed to the bearing inner space side surface other than the sliding surface of the member with the rolling element. Rolling bearing for motor.   The rolling bearing for motor according to claim 1, wherein the auxiliary agent for grease is fixed in a state of being contained in a resin.   The rolling bearing for a motor according to claim 2, wherein the resin is an epoxy resin.   When the grease auxiliary agent is fixed in a state where it is contained in the resin, the proportion of the grease auxiliary agent is 10% by weight or more based on the total of the grease auxiliary agent and the resin. The rolling bearing for a motor according to claim 2 or 3, characterized in that.   The rolling bearing for motor according to any one of claims 1 to 4, wherein the auxiliary agent for grease is a foaming agent or an antioxidant.   6. The rolling bearing for motor according to claim 5, wherein the foaming agent is at least one selected from organic foaming agents.   The rolling bearing for a motor according to claim 6, wherein the organic foaming agent is azodicarbonamide.   The rolling bearing for a motor according to claim 5, wherein the antioxidant is an amine-based antioxidant.   9. The rolling bearing for a motor according to claim 1, wherein the auxiliary agent for grease is fixed to a surface of the seal member on a space in the bearing inner space.   A motor bearing seal member, wherein the seal member is a motor bearing seal member to which an auxiliary agent for grease is fixed, wherein the seal member is used for the rolling bearing for motor according to claim 9.

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