JP2016186355A - Rolling bearing cage and rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing cage capable of improving peeling resistance thereof while eliminating the possibility of elution even in lubricating oil containing sulfur-based additive etc., and to provide a rolling bearing including the same.SOLUTION: A cage 2 holds needle rollers 3 as rolling elements of a needle roller bearing 1. At least on the slide contact surface with the needle rollers 3 and the slide contact surface with the other members in the outer surface of the cage 2, resin coatings are formed. The substrate surface where the resin coatings are each formed has a root-mean-square slope (R▵q) of greater than or equal to 0.1 and smaller than 0.2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rolling bearing cage and a rolling bearing provided with the rolling bearing cage, and more particularly to a rolling bearing cage in which a resin film is formed on the surface of a base material having a predetermined surface property.

  The roller bearing that supports the rotating shaft includes a plurality of rollers (rolling elements) and a cage that holds the plurality of rollers. FIG. 3 is a longitudinal sectional view of an engine using roller bearings at the small end and the large end of the connecting rod. As shown in FIG. 3, the engine connects the crankshaft 21 that outputs rotational motion, the piston 22 that performs linear reciprocating motion by combustion of the air-fuel mixture, and the crankshaft 21 and piston 22 to rotate the linear reciprocating motion. And a connecting rod 24 for converting into motion. The crankshaft 21 rotates about the rotation center axis and balances rotation by a balance weight. The connecting rod 24 is formed by providing a large end portion below the linear rod body and a small end portion above. The crankshaft 21 is connected to the large end portion of the connecting rod 24, and the piston pin 23 connecting the piston 22 and the connecting rod 24 is connected to the small end portion of the connecting rod 24 via roller bearings 25 and 26 attached to the engaging holes, respectively. It is supported rotatably.

  As the roller bearings 25 and 26, needle roller bearings that can receive a heavy load and have high rigidity despite the small bearing projected area are used. The needle roller bearing includes a plurality of needle rollers and a cage that holds the plurality of needle rollers. The cage is provided with pockets for holding the needle rollers, and the interval between the needle rollers is held by a pillar portion located between the pockets. Here, the needle roller bearings at the small end and the large end of the connecting rod positively reduce the load at the small end and the large end in order to reduce the load applied to the needle roller bearing by the rotation and revolution of the needle roller. It is used in an outer diameter guide in which an outer diameter surface of a cage is brought into contact with an inner diameter surface of an engagement hole provided at an end portion.

  On the other hand, in general rolling bearings, the inside of the bearing is hermetically sealed with an inner ring, an outer ring, a sealing material, etc., and a rolling element and a cage are provided inside the bearing, and grease is filled. Always lubricated. On the other hand, since the needle roller bearing does not have an inner ring, an outer ring, a sealing material, and the like, the inside of the bearing is not sealed and grease cannot be filled in the bearing. Therefore, when rotating the needle roller bearing, it is necessary to always supply lubricating oil to the sliding portion with a pump or the like.

  Since the pump or the like starts operating simultaneously with the rotation of the needle roller bearing, the lubricating oil has not yet reached the entire needle roller bearing immediately after the rotation starts, and sufficient lubrication is not performed. For this reason, a large friction is generated between the cage and the needle roller, and the surface of the cage or needle roller is worn, or the cage outer diameter surface and the actual housing inner surface are worn. There is a risk of burning. Therefore, in order to prevent wear and seizure immediately after the start of rotation of the needle roller bearing, a technique has been proposed in which a film having lubricity is formed in advance on the surface of the cage.

  For example, a hard diamond-like carbon (hereinafter referred to as DLC) film is formed on the guide surface of a rolling element of a cage made of steel having a hardened layer formed on the surface by carburizing treatment by sputtering or the like. A method of forming a soft metal film such as is known (see Patent Document 1).

  A technique for directly forming the soft metal film on the surface of the cage by a plating method has also been proposed. For example, a method of forming a silver plating film of about 25 to 50 μm on the surface of low carbon steel is known (see Patent Document 2). This silver plating film reduces friction between the cage and needle rollers, and between the cage outer diameter surface and the housing, respectively. It can be prevented.

  In addition, a method for improving the wear resistance of a coating by surface treatment in which irregularities are provided on the surface of the substrate and a solid lubricating coating is applied thereon (see Patent Document 3) is known.

Japanese Patent Laying-Open No. 2005-147306 JP 2002-195266 A JP 2008-284632 A

  However, in the method shown in Patent Document 1, the hard coating is exposed after the soft metal is worn away and the inner diameter portion of the housing slides on the hard coating. In this case, the cage is not worn, but there is a possibility that the inner diameter portion of the housing is worn by the hard coating on the surface of the cage. Moreover, since the carburizing process is performed on the cage from the viewpoint of manufacturing, the DLC film is formed by the sputtering apparatus, and the soft metal film is formed, the work process is complicated and requires a lot of man-hours. Moreover, since the sputtering apparatus is expensive and the production efficiency is not good, there is a problem that the processing using the apparatus is expensive.

  In the method shown in Patent Document 2, in a lubricating system containing a sulfur-based additive, a silver plating film formed on the surface of the cage is combined with a sulfur component contained in the lubricating oil to form silver sulfide. The surface of the silver plating film is coated. Since this silver sulfide is fragile compared to silver, the coating is peeled off or inferior in oil resistance, so the coating is dissolved by the lubricating oil. As a result, there is a problem that the friction between the outer diameter surface of the cage where the silver plating film has disappeared and the inner diameter surface of the housing increases, and seizure tends to occur. Similarly, the copper plating film also has a problem that copper sulfide is generated and the lubricity of the cage deteriorates due to peeling or dissolution of the film.

  The method shown in Patent Document 3 optimizes the surface properties of the substrate surface to improve the wear resistance, but has a problem that the peel resistance is not improved.

  The present invention has been made in order to cope with such a problem, and is capable of improving the peeling resistance and retaining for a rolling bearing that does not elute even in a lubricating oil containing a sulfur-based additive or the like. It is an object of the present invention to provide a container and a rolling bearing provided with the same.

  A rolling bearing retainer according to the present invention is a rolling bearing retainer for retaining a rolling element in a rolling bearing, and at least a sliding contact surface with the rolling element and other members of the outer surface of the retainer. A resin film is formed on the sliding contact surface, and the root mean square slope (RΔq) of the base surface on which the resin film is formed is 0.1 or more and less than 0.2. In addition, the arithmetic average roughness (Ra) of the base surface on which the resin coating is applied is 0.5 to 1.5 μm. In addition, the cage body is made of an iron-based metal material selected from bearing steel, carburized steel, carbon steel for machine structure, cold rolled steel, and hot rolled steel.

  The rolling bearing according to the present invention includes a plurality of rolling elements and the cage according to the present invention that holds the rolling elements. In particular, the rolling bearing is attached to an engagement hole provided at an end of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion. Further, the rolling element is a roller shape.

  The rolling bearing cage of the present invention has a resin coating on at least a sliding contact surface with the rolling element and a sliding contact surface with another member of the outer surface of the rolling bearing cage that holds the rolling element in the rolling bearing. Since the root mean square slope (RΔq) of the base surface on which the resin film is formed is 0.1 or more and less than 0.2, the peeling on the cage sliding contact surface is suppressed and the peeling life is reduced. Since it is improved and has excellent oil resistance, the cage base material is not exposed over a long period of time, and seizure can be prevented.

  Since the rolling bearing of the present invention includes a plurality of rolling elements and the cage of the present invention that holds the rolling elements, it can maintain lubricity on the cage sliding surface over a long period of time and can prevent seizure. .

  Also, this rolling bearing supports a crankshaft that outputs rotational motion and is attached to an engagement hole provided at the end of a connecting rod that converts linear reciprocating motion into rotational motion, thus forming a conventional metal plating As compared with the case, wear on the outer diameter surface of the cage and the inner diameter surface of the engagement hole is prevented for a long period from the beginning of sliding, and the life of the entire apparatus can be extended.

It is a longitudinal cross-sectional view of the 4-cycle engine which uses a needle roller bearing as an example of the rolling bearing of this invention. It is a perspective view which shows the needle roller bearing using the cage for rolling bearings of this invention. It is a longitudinal cross-sectional view of the engine which used the roller bearing for the small end part and large end part of a connecting rod. It is the figure which summarized peeling life by using RΔq as a parameter.

  The cage for rolling bearings of the present invention holds rolling elements in a rolling bearing. Moreover, the rolling bearing of this invention hold | maintains a some rolling element using this holder | retainer.

  A rolling bearing according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a four-cycle engine using a needle roller bearing as an example of the rolling bearing of the present invention. In the four-cycle engine, the intake valve 7a is opened, the exhaust valve 8a is closed, and an air-fuel mixture obtained by mixing gasoline and air is sucked into the combustion chamber 9 via the intake pipe 7, and the intake valve 7a is closed and the piston 6 And a compression stroke in which the air-fuel mixture is compressed, an explosion stroke in which the compressed air-fuel mixture is exploded, and an exhaust stroke in which the exploded combustion gas is exhausted through the exhaust pipe 8 by opening the exhaust valve 8a. A piston 6 that performs linear reciprocating motion by combustion in these strokes, a crankshaft 4 that outputs rotational motion, a connecting rod 5 that connects the piston 6 and the crankshaft 4 and converts linear reciprocating motion into rotational motion, Have The crankshaft 4 rotates around the rotation center shaft 10 and balances rotation by a balance weight 11.

  The connecting rod 5 is formed by providing a large end portion 13 below the linear rod body and a small end portion 14 above. The crankshaft 4 is rotatably supported via a needle roller bearing 1 a attached to the engagement hole of the large end portion 13 of the connecting rod 5. The piston pin 12 that connects the piston 6 and the connecting rod 5 is rotatably supported via a needle roller bearing 1 b that is attached to the engagement hole of the small end portion 14 of the connecting rod 5.

  FIG. 2 is a perspective view showing a needle roller bearing using the rolling bearing retainer of the present invention. As shown in FIG. 2, the needle roller bearing 1 includes a plurality of needle rollers 3 and a cage 2 that holds the needle rollers 3 at regular intervals or unequal intervals. This cage 2 is a rolling bearing cage of the present invention. The inner ring and the outer ring are not provided, and the shaft such as the crankshaft 4 and the piston pin 12 is directly inserted into the inner diameter side of the cage 2, and the outer diameter side of the cage 2 is fitted into the engagement hole of the connecting rod 5 as a housing. (See FIG. 1). Since the needle roller 3 having no inner and outer rings and having a smaller diameter than the length is used as a rolling element, the needle roller bearing 1 is more compact than a general rolling bearing having inner and outer rings. Become.

  The cage 2 is provided with pockets 2a for holding the needle rollers 3, and the intervals between the needle rollers 3 are held by the column portions 2b positioned between the pockets. A resin film described later is formed on the surface portion of the cage 2. The surface portion of the cage that forms the resin coating is at least a sliding contact surface with the rolling element and a sliding contact surface with another member in the entire outer surface of the cage. The outer surface is the outermost surface of the cage, and is the surface that actually comes into sliding contact with the rolling elements and other members. These outer surfaces are also parts that come into contact with lubricating oil or the like. The other members are inner and outer rings, connecting rod end portions, and the like.

  Since manufacture is easy, it is preferable to form a resin film on the whole outer surface of the holder | retainer 2 including the surface of the pocket 2a which contacts the needle roller 3. FIG. Further, in addition to the surface portion of the cage 2, a similar resin film can be formed on the surface of the needle roller 3 that is a rolling element and the engagement hole inner diameter surface of the connecting rod 5.

  The main body of the cage 2 is preferably an iron-based metal material. In particular, since the cage surface is roughened and a resin film to be described later is formed and used, bearing steel, carburized steel, and carbon for mechanical structure are used. Steel, cold rolled steel or hot rolled steel is preferred.

  As a method for roughening the surface of the cage, after removing contamination on the surface of the substrate by immersion cleaning with an organic solvent, ultrasonic cleaning, steam cleaning, acid / alkali cleaning, etc., mechanical methods, chemical methods, etc. Can be done. Examples of the mechanical method include a method in which a polygonal grid, a spherical bead, or the like is projected onto the surface of the substrate to roughen the surface. The chemical method includes a chemical conversion treatment method in which the manganese phosphate coating formed on the substrate surface is removed from the substrate with an acidic chemical or the like to roughen the surface. Among these, the method of projecting a spherical bead onto the surface of the substrate to roughen the surface is preferable because the roughening properties can be easily controlled.

  The surface of the main body of the roughened cage 2 before the film formation has a root mean square slope (RΔq) of 0.1 or more and less than 0.2. Here, the root mean square slope (RΔq) is the root mean square of the local slope at the reference length, and is a numerical value calculated in accordance with JIS B0601 (2001). For example, a contact-type surface roughness measuring machine It is calculated from data measured by the above. When the root mean square slope (RΔq) is less than 0.1, the surface area for adhesion of the coating becomes small, and the adhesion of the coating becomes insufficient. On the other hand, when it is 0.2 or more, the tip angle of the convex portion becomes too large, and the stress generated in the coating in contact with the base material convex portion when receiving a load from the coating surface increases. Therefore, the accumulation of fatigue on the coating becomes too large, and the peeling life is shortened.

  In addition, the surface of the main body before the coating of the roughened cage 2 has an arithmetic average roughness (Ra) calculated in accordance with JIS B0601 (2001) of 0.5 μm to 1.5 μm. Is preferred. When the arithmetic average roughness (Ra) is within this range, the peeling life is improved.

  The resin film that can be formed on the surface of the roughened iron-based substrate is not particularly limited as long as it is a material that has oil resistance, has high film strength when formed into a film, and is excellent in wear resistance. Examples of such resins include epoxy resins, phenol resins, polycarbodiimide resins, furan resins, bismaleimide triazine resins, unsaturated polyester resins, silicone resins, polyamino bismaleimide resins, aromatic polyimide resins and other thermosetting resins, polyolefins Resin, polyacetal resin, polyamide resin, polyphenylene ether resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyetherimide resin, thermoplastic polyimide resin, aromatic polyamideimide resin, polybenzimidazole resin, polyether ketone resin And thermoplastic resins such as polyether nitrile resin, fluororesin, and aromatic polyester resin. Among these, preferred are aromatic polyamideimide resins, aromatic polyimide resins, epoxy resins, phenol resins, polyphenylene sulfide resins and the like.

  In the present invention, a particularly preferable synthetic resin is a polyimide resin excellent in film forming ability. Examples of the polyimide resin include a polyimide resin having an imide bond in the molecule and a polyamideimide resin having an imide bond and an amide bond in the molecule. Among these, unlike an aromatic polyimide resin, a polyamideimide resin having a repeating unit of an amide bond and an imide bond in a resin solution state without passing through a precursor is particularly preferable in the present invention. Further, diisocyanate-modified, BPDA-modified, sulfone-modified and rubber-modified resins of polyamideimide resin can be used. As a commercial item of a polyamideimide resin varnish, for example, HPC9000 manufactured by Hitachi Chemical Co., Ltd. may be mentioned.

  Using the above polyamideimide resin varnish, a resin film is formed on the surface of the cage that has been roughened by spray coating, dip coating, electrostatic coating, tumbler coating, electrodeposition coating, etc. To do. After the coating is formed, solvent removal, drying, melting, cross-linking, etc. are performed by heat treatment to complete the cage. In the process of film formation, the excessively adhered varnish can be removed by physical and chemical methods such as wiping, centrifugation, air blowing, etc., and adjusted to a desired thickness. When the film thickness is increased, it may be overcoated. Moreover, a silane coupling agent process can be performed before film formation.

  The film thickness is preferably 5 to 50 μm. More preferably, it is 10-50 micrometers. When the thickness of the coating is less than 5 μm, the durability is insufficient. On the other hand, when it exceeds 50 μm, the roundness of the cage may be deteriorated.

  The above-mentioned film, particularly the polyimide resin film, does not swell or dissolve even when immersed in a lubricating oil containing a sulfur-based additive by forming it on the substrate surface having the above-mentioned specific properties. Therefore, even if the base material is a metal with low sulfidation resistance, metal elution into the lubricating oil hardly occurs. For this reason, the rolling bearing retainer and the rolling bearing of the present invention can be suitably used in an environment that comes into contact with lubricating oil containing a sulfur-based additive. As such an environment, for example, as described above, it is attached to a connecting rod of a four-cycle engine and comes into contact with an air-fuel mixture or engine oil mixed with gasoline and lubricating oil, or a rolling bearing. The case where it contacts by lubrication etc. to a cage | basket pocket part is mentioned.

  The type of the rolling bearing of the present invention may be either a radial bearing or a thrust bearing. Further, the shape of the rolling element is not particularly limited, but the effect of the present invention can be further enjoyed in the case of a roller shape or a needle roller shape. The roller shape includes a cylindrical roller, a tapered roller, and a spherical roller.

  By making the shape of the rolling element into a roller shape, the rolling bearing of the present invention is attached to the engagement holes provided in the small end portion and the large end portion of the connecting rod as described above, and the piston pin and the crankshaft are mounted. It can be supported and can receive a heavy load despite the small bearing projected area. In particular, a rolling bearing using a highly rigid needle roller as a rolling element can receive a higher load than a rolling bearing using a roller as a rolling element.

  Further, the rolling bearing of the present invention can be suitably used as a rolling bearing used in a compressor for an air conditioner such as an air conditioner or a car air conditioner in addition to the connecting rod described above.

Example 1 to Example 2, Comparative Example 1 to Comparative Example 8
In order to evaluate the peel resistance of the coating formed on the cage surface, a “Saban-type friction and wear test” was performed, and the peel life was measured. In addition, a “lubricating oil immersion test” was performed in order to measure the amount of the coating component dissolved in the lubricating oil. The results are shown in Table 1. Further, FIG. 4 shows the result of the stripping life summarized by using RΔq as a parameter. Details of test conditions, test pieces, measurement methods, measurement equipment, and the like are shown below.

(1) Test piece pretreatment In Examples 1, 2 and 6, the conditions were adjusted so that the surface properties shown in Table 1 were obtained, and spherical beads were projected onto the substrate surface to roughen the surface. . In Comparative Examples 1 and 2, a zinc phosphate (Ca-containing) coating (Palbond 880 manufactured by Nihon Parkerizing Co., Ltd.) and a manganese phosphate coating (Palphos M1A manufactured by Nihon Parkerizing Co., Ltd.) were applied. In Comparative Example 3, Comparative Example 4, and Comparative Example 5, the conditions were adjusted so that the surface properties shown in Table 1 were obtained, and a polygonal grid was projected onto the substrate surface to roughen the surface. Comparative Example 7 is an example of Ag plating after Cu strike plating, and Comparative Example 8 is an example of Cu plating.

(2) Sabang type friction and wear test (a) Test conditions: surface pressure 280 MPa, sliding speed 180 m / min, lubricating oil Mineral oil (VG2)
(B) Specimen: Ring (rotation side SUJ2 Quenching and tempering treatment φ40 × R60 × 10) Pretreatment for roughening the outer diameter surface and then PAI coating treatment (c) Coating: Polyamideimide resin (HPC-manufactured by Hitachi Chemical Co., Ltd.) 9000) The film was applied so as to have a film thickness of 15 to 25 μm, followed by primary drying at 80 ° C. for 30 minutes, secondary drying at 150 ° C. for 15 minutes, and baking at 270 ° C. for 30 minutes.
(D) Mating material: flat plate (fixed side SCM415 carburizing quenching tempering roughness Ra 0.01 μm)
(E) Evaluation method: The time until peeling occurs in the coating film is defined as the lifetime.

(3) Lubricating oil immersion test (a) Three test pieces each coated with a coating and three plated test pieces used in the Sabang-type frictional wear test are immersed in 2.2 g of 150 ° C. lubricating oil for 200 hours.
(B) After a predetermined time, the concentration of the coating component eluted in the lubricating oil is measured. Concentration measurement was quantified by fluorescent X-ray measurement.
(C) Test piece: 3 pieces of 3 × 3 × 20 SCM415 materials (total surface area of 3 pieces: 774 mm ³ )
(D) Lubricating oil: 2.2 g of poly-α-olefin oil added with 1% by weight of ZnDTP (LUBRIZOL677A, LUBRIZOL)
(E) X-ray fluorescence measurement apparatus: Rigaku ZSX100e (manufactured by Rigaku Corporation)

  As apparent from the results shown in Table 1 and FIG. 4, the rolling bearing cages of each example have a root mean square slope (RΔq) of the base surface on which the resin coating is applied of 0.1 or more and 0.00. In the range of less than 2, the peel life is specifically improved. The comparative examples in which RΔq is less than 0.1 and 0.2 or more do not improve the peeling life. In Comparative Example 7 and Comparative Example 8, which are metal platings conventionally used, a metal component is eluted in the lubricating oil in the lubricating oil immersion test. In particular, the result was a large amount of elution of copper plating.

  The rolling bearing retainer of the present invention has an improved peel life and a coating that does not elute even in a lubricating oil containing a sulfur-based additive or the like is formed. Therefore, in a lubricating oil containing a sulfur-based additive, Therefore, it can be suitably used as a rolling bearing used under lean lubrication conditions.

DESCRIPTION OF SYMBOLS 1 Needle roller bearing 2 Cage 3 Needle roller 4 Crankshaft 5 Connecting rod 6 Piston 7 Intake pipe 8 Exhaust pipe 9 Combustion chamber 10 Rotation center axis 11 Balance weight 12 Piston pin 13 Large end 14 Small end 21 Crankshaft 22 Piston 23 Piston pin 24 Connecting rod 25 Roller bearing 26 Roller bearing

Claims (6)

A rolling bearing cage for holding rolling elements in a rolling bearing,
Of the outer surface of the cage, a resin film is formed on at least the sliding contact surface with the rolling element and the sliding contact surface with the other member,
A rolling bearing cage, wherein a root mean square slope (RΔq) of a base surface on which the resin film is formed is 0.1 or more and less than 0.2.   2. The rolling bearing retainer according to claim 1, wherein the arithmetic average roughness (Ra) of the base surface is 0.5 μm or more and 1.5 μm or less.   The said cage main body consists of ferrous metal materials chosen from bearing steel, carburized steel, carbon steel for machine structure, cold rolled steel, and hot rolled steel. Roller bearing cage.   A rolling bearing comprising a plurality of rolling elements and a cage for holding the rolling elements, wherein the cage is the rolling bearing cage according to any one of claims 1 to 3. A rolling bearing characterized by that.   The rolling bearing according to claim 4, wherein the rolling bearing is attached to an engagement hole provided at an end of a connecting rod that supports a crankshaft that outputs rotational motion and converts linear reciprocating motion into rotational motion. bearing.   6. The rolling bearing according to claim 4, wherein the rolling element has a roller shape.

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