WO2017038754A1

WO2017038754A1 - Angular ball bearing

Info

Publication number: WO2017038754A1
Application number: PCT/JP2016/075169
Authority: WO
Inventors: 裕士恩田
Original assignee: Ntn株式会社
Priority date: 2015-09-01
Filing date: 2016-08-29
Publication date: 2017-03-09
Also published as: JP2017048841A

Abstract

Provided is an angular ball bearing having excellent lubrication characteristics in a guiding surface of a holding implement, in which noise can be minimized. An angular ball bearing 1 is provided with an inner race 2 and an outer race 3 which are bearing races, a plurality of balls 4 placed between the inner and outer races, and a holding implement 5 for holding the balls 4. A lubricant is supplied to or sealed in an internal space of the bearing, the holding implement 5 has a flocked part 6 guided by the outer race 3 and made by flocking fibers at least on an outer race guiding surface 5d of the holding implement 5, the fibers are synthetic resin fibers, and the flocked part 6 is an electrostatic flocked part.

Description

Angular contact ball bearings

The present invention relates to an angular ball bearing that is used at high speed rotation, such as supporting a machine tool spindle.

Among rolling bearings, angular contact ball bearings are capable of receiving a combined load consisting of a radial load and a relatively large axial load, so the direction of load under heavy loads such as machine tools, medical equipment, construction machinery, and agricultural machinery. Are often used in applications that require high-speed rotation even in various environments. Angular contact ball bearings that support machine tool spindles are required to rotate stably and at high speeds in order to increase machining efficiency. Oil mist lubrication, air-oil lubrication, and bearings that supply lubricating oil from the outside are required for lubrication. Grease lubrication that encloses grease inside is used.

Many of the cages for holding the balls of such angular ball bearings are guided by a bearing outer ring. In this type, when a large frictional force is generated on the guide surfaces at the outer diameter of the cage and the inner diameter of the outer ring, the cage may vibrate due to this force and abnormal noise may be generated. This is considered to be caused by the deterioration of the lubrication state at the guide surface.

On the other hand, Patent Document 1 describes that, in an angular ball bearing having an outer ring guide cage, dimple processing is performed on the outer circumferential surface of the cage in order to improve the lubrication state on the cage guide surface. ing. In Patent Document 1, at least one of alicyclic urea and aromatic urea that can withstand severe shearing is used as a thickener for the grease to be enclosed, and low viscosity oil is used as the base oil. In this bearing, innumerable dimple-like recesses function as a grease reservoir, and this, combined with the type of thickener and the viscosity of the base oil, makes it difficult for vibration and noise to occur even at high speeds.

JP 2014-159842 A

As a method of suppressing the generation of abnormal noise, it is conceivable to increase the amount of lubricant retained on the guide surface of the cage as much as possible. However, the technique disclosed in Patent Document 1 has a limited increase in the amount of lubricant retained due to the formation of dimple-shaped recesses, and further improvement is necessary. In Patent Document 1, grease types (thickener type / base oil viscosity) are also limited. In order to suppress the generation of abnormal noise in angular ball bearings of various sizes and types of lubrication, it is required to improve the lubrication state on the guide surface of the cage without greatly depending on the type of lubricant.

The present invention has been made to cope with such a problem, and an object thereof is to provide an angular ball bearing that has excellent lubrication characteristics on the guide surface of the cage and can suppress the occurrence of abnormal noise.

The angular contact ball bearing of the present invention includes inner and outer rings that are raceways, a plurality of balls interposed between the inner and outer rings, and a cage that holds the balls, and a lubricant is supplied to the bearing inner space. An enclosed angular ball bearing, wherein the cage is guided by the outer ring or the inner ring, and has a flocking portion formed by flocking fibers on at least a guide surface of the cage. Here, the guide surface of the cage is a contact surface with the guide-side raceway in the cage. In particular, the cage is guided by the outer ring, and the flocked portion is provided on the outer ring guide surface of the cage.

The fiber is a synthetic resin fiber, and the flocked portion is an electrostatic flocked portion. Moreover, the said hair transplant part is provided continuously to the width surface of the said holder | retainer, It is characterized by the above-mentioned. Moreover, the said lubricant is hold | maintained at the said hair transplant part, It is characterized by the above-mentioned.

The angular contact ball bearing of the present invention includes inner and outer rings that are raceways, a plurality of balls interposed between the inner and outer rings, and a cage that holds the balls, and a lubricant is supplied to the bearing inner space. Since the cage has a structure to be sealed, the cage is guided by the outer ring or the inner ring, and has a planted portion formed by planting fibers on at least the guide surface of the cage, so that lubricating oil or the like is sufficiently applied to the planted portion. It is held, has excellent lubrication characteristics on the guide surface of the cage (decrease in frictional force, etc.), and can suppress abnormal noise. In particular, in the outer ring guide retainer, since the flocked portion is provided on the outer ring guide surface of the retainer, the noise problem in the conventional angular ball bearing using this type of retainer can be solved.

In addition, since it is a simple structure that is configured by bonding and fixing the flocked portion to the clearance (clearance) between the race ring and the cage guide surface, the existing cage can be used as it is without being shaped (such as dimples). it can. Further, since the grease and the lubricating oil are held in the flocked portion, these lubricants are not easily subjected to direct shearing, and the lubrication state on the cage guide surface can be improved without largely depending on the lubricant type.

In addition, since the fiber is a synthetic resin fiber and the flocked portion is an electrostatic flocked portion, swelling and dissolution due to oil are difficult to occur, and it is chemically stable and becomes a homogeneous and dense flocked portion.

Further, since the flocked portion is continuously provided up to the width surface of the cage, the lubricant is also held in this portion, and the lubricating oil is applied from the width surface to the cage guide surface by the centrifugal force when the cage rotates. Can supply. Compared with the cage guide surface, the width surface of the cage does not interfere with other parts and is less likely to drop off.

It is a partial sectional view of an angular contact ball bearing concerning an example of the present invention. It is a partial perspective view of the angular ball bearing in FIG. It is a partial cross section figure of the angular ball bearing concerning other examples of the present invention. It is a partial cross section figure of the angular ball bearing concerning other examples of the present invention. It is a partial perspective view of the angular ball bearing in FIG.

An embodiment of the angular ball bearing of the present invention will be described with reference to FIGS. FIG. 1 is a partial cross-sectional view of an angular contact ball bearing incorporating a resin cage having a flocked portion (guide surface) as an angular contact ball bearing of the present invention, and FIG. 2 is a partially enlarged view of the angular contact ball bearing. It is. In the angular ball bearing 1 shown in FIG. 1, a plurality of balls 4 are arranged in a circumferential direction in a raceway space between an inner ring 2 and an outer ring 3, and the inner ring 2, the outer ring 3, and the balls 4 have a predetermined contact angle. It is provided with θ. These balls 4 are held at equal intervals in the circumferential direction by a cage 5. This angular ball bearing 1 does not use a seal member, and its lubrication type is air oil lubrication or oil mist lubrication that constantly supplies lubricating oil from the outside of the bearing to the inside of the bearing. Moreover, it is good also as grease lubrication which encloses grease irrespective of the presence or absence of a sealing member. The cage 5 is an outer ring guide system, and is guided to the outer ring 3 when the outer ring guide surface 5 d of the cage 5 comes into contact with the inner diameter surface 3 a of the outer ring 3. The outer ring guide surface 5d is provided on a part (one side in the axial direction) of the outer diameter surface 5a of the cage 5.

In this form of the angular ball bearing 1, a flocked portion 6 formed by flocking fibers on the outer ring guide surface 5d of the cage 5 is formed. As shown in FIG. 2, there is a certain gap (clearance) between the outer ring guide surface 5 d of the cage 5 and the inner diameter surface 3 a of the outer ring 3, and the flocked portion 6 is formed in this gap. By forming the flocked portion 6 on the outer ring guide surface 5d, lubricating oil is held in the flocked portion, and generation of large friction due to sliding contact between the outer ring 3 and the cage 5 can be prevented.

In the present invention, the contact with the raceway surface due to the vibration of the cage can be buffered by forming the flocked portion 6 on the outer ring guide surface 5d. In addition to the improvement of the lubrication characteristics at the guide surface of the cage described above, the occurrence of abnormal noise can be effectively suppressed by such an action.

The flocking part should just be formed in the guide surface of a holder | retainer at least. That is, it may be formed on the outer ring guide surface when the cage is an outer ring guide, and on the inner ring guide surface when the cage is an inner ring guide. Moreover, it does not need to be formed in the whole range of a guide surface, You may form limiting to only the pillar part of a holder | retainer, or only a collar part (ring part). In the form shown in FIGS. 1 and 2, the flocked portion 6 is formed on the entire outer ring guide surface 5 d of the cage 5.

Another embodiment of the angular ball bearing of the present invention will be described with reference to FIG. FIG. 3 is a partial sectional view of an angular ball bearing incorporating a resin cage having a flocked portion (guide surface and width surface) as an angular ball bearing of the present invention. In the angular ball bearing 1 shown in FIG. 3, the flocked portion 6 is formed on the width surface 5b in addition to the outer ring guide surface 5d. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG. The width surface 5b on which the flocked portion 6 is formed is a width surface on the outer ring guide surface 5d side (left side in the figure). The flocked portion 6 is formed continuously from the outer ring guide surface 5d to the width surface 5b. Compared to the cage guide surface, the width surface of the cage does not interfere with other parts, and the flocked portion is less likely to fall off. Further, since the lubricating oil is also held in the flocked portion of the width surface 5b, the lubricating oil can be supplied from the width surface to the cage guide surface through the flocked portion by the centrifugal force when the cage rotates.

Another embodiment of the angular ball bearing of the present invention will be described with reference to FIGS. FIG. 4 is a partial cross-sectional view of an angular contact ball bearing (with a seal member) incorporating a resin cage having a flocked portion (guide surface) as an angular contact ball bearing of the present invention, and FIG. 5 is this angular contact ball bearing. FIG. The angular ball bearing 1 of the form shown in FIG. 4 and FIG. 5 has a pair of seal members 7 at both axial opening portions between the inner and outer rings, and seals the bearing space. Grease 8 is sealed in the bearing space. The cage 5 is an outer ring guide system, and is guided to the outer ring 3 when the outer ring guide surface 5 d of the cage 5 comes into contact with the inner diameter surface of the outer ring 3. The outer ring guide surface 5d is provided at a part (both ends in the axial direction) of the outer diameter surface 5a of the cage 5. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

In this form of the angular ball bearing 1, a flocked portion 6 formed by flocking fibers on the outer ring guide surface 5d of the cage 5 is formed. As shown in FIG. 5, there is a certain gap (clearance) between the outer ring guide surface 5 d of the cage 5 and the inner diameter surface 3 a of the outer ring 3, and the flocked portion 6 is formed in this gap. By forming the flocked portion 6 on the outer ring guide surface 5d, grease is held in the flocked portion, and generation of large friction due to sliding contact between the outer ring 3 and the cage 5 can be prevented.

In this embodiment, similarly to the embodiment shown in FIG. 3, the flocked portion 6 may also be formed on the width surface 5b of the cage 5. In the case of grease lubrication, the grease is fixed and held on the flocked portion, and the lubrication life can be extended.

In addition, in the form shown in FIG. 1 to FIG. 4, a flocked portion may be further formed on the inner diameter surface 5 c of the cage 5. By forming the flocked portion on the surface that is not the guide surface, dropping or the like is unlikely to occur, and the amount of lubricating oil or grease held in the cage increases, so that the lubrication characteristics on the rolling surface and the like are improved.

The retainer 5 is a machined retainer, and pocket portions for retaining balls as rolling elements are provided at regular intervals in the circumferential direction on an annular retainer body. The main object of the present invention is to prevent abnormal noise in a high-speed angular contact ball bearing using a resin cage. The resin cage is made of, for example, a polyamide resin such as a phenol resin, a polyether ether ketone (PEEK) resin, a polyphenylene sulfide (PPS) resin, a thermoplastic polyimide resin, a polyamideimide resin, a nylon 66 resin, or a nylon 46 resin. It is manufactured by injection molding using a resin composition containing a reinforcing fiber such as carbon fiber or glass fiber and other additives as a material. In particular, a phenol resin is preferable because it has a high elastic modulus at a high temperature and can cope with high-speed rotation.

The phenol resin is a resin obtained by reacting phenols such as phenol, cresol, xylenol, alkylphenol, halogenated phenol, and resorcin with aldehydes such as formaldehyde in the presence of a catalyst. For example, when producing a cage with a novolac type phenolic resin, the above-mentioned reinforcing fibers and other additives are added to this phenolic resin powder, and further, a curing agent such as hexamethylenetetramine, and magnesium oxide if necessary. It can be produced by heating and melting a mixture obtained by blending and uniformly mixing the curing accelerator and injecting the mixture into a mold.

As described above, the case of the resin cage has been described as the cage, but the angular ball bearing of the present invention is not limited to this, and any material such as a metal material can be adopted. Also, the cage type is not particularly limited, and a crown-shaped cage, a corrugated cage, or the like may be used as long as a flocked portion can be formed on the guide surface. In accordance with the material and type of the cage, the short fiber material and the kind of adhesive to be described later used for the flocked portion are determined.

The flocked portion 6 is formed by flocking short fibers. Spraying or electrostatic flocking can be employed as a flocking method. Even on a curved surface such as the guide surface of the cage, it is preferable to employ electrostatic flocking because a large amount of fibers can be densely and vertically planted in a short time. As the electrostatic flocking method, a known method can be adopted.For example, after applying an adhesive to a range where electrostatic flocking is performed, the short fibers are charged and flocked substantially perpendicularly to the adhesive application surface by electrostatic force, The method of performing a drying process, a finishing process, etc. is mentioned.

The short fiber used for flocking is not particularly limited as long as it can be used as a short fiber for flocking. For example, (1) polyolefin resin such as polyethylene and polypropylene, polyamide resin such as nylon, aromatic polyamide resin, polyethylene terephthalate, Polyester resin such as polyethylene naphthalate, polyethylene succinate, polybutylene terephthalate, synthetic resin fiber such as acrylic resin, vinyl chloride, vinylon, (2) inorganic fiber such as carbon fiber, glass fiber, (3) rayon, acetate, etc. And natural fibers such as cotton, silk, hemp and wool. These may be used independently and 2 or more types may be used together. It is preferable to use synthetic resin fiber among the above because it is difficult to cause swelling and dissolution with oil, is chemically stable, can produce a large amount of homogeneous fibers, and can be obtained at low cost.

The shape of the short fiber is not particularly limited as long as it does not adversely affect the bearing function. The specific shape is preferably, for example, a length of 0.5 to 2.0 mm and a thickness of 0.5 to 50 dtex, and the density of short fibers in the flocked part is occupied by the fibers per planted area. The proportion is preferably 10 to 30%. About the short fiber length of the flocked part formed in a guide surface, it shall be below the clearance gap (clearance) between a bearing ring and a cage guide surface. There are straight and bend (shape where the tip is bent) as the shape of the short fiber, and the cross-sectional shape is circular or polygonal. The bend shape can hold the lubricant more strongly than the straight shape. By using the short fibers having a polygonal cross section, the surface area can be made larger than that of the short fibers having a circular cross section, and the surface tension of the lubricant can be increased.

Examples of the adhesive include an adhesive mainly composed of urethane resin, epoxy resin, acrylic resin, vinyl acetate resin, polyimide resin, silicone resin and the like. For example, urethane resin solvent adhesive, epoxy resin solvent adhesive, vinyl acetate resin solvent adhesive, acrylic resin emulsion adhesive, acrylic ester-vinyl acetate copolymer emulsion adhesive, vinyl acetate emulsion adhesive And urethane resin emulsion adhesives, epoxy resin emulsion adhesives, polyester emulsion adhesives, ethylene-vinyl acetate copolymer adhesives, and the like. These may be used independently and 2 or more types may be used together.

The angular ball bearing of the present invention is lubricated with a lubricant (lubricant or grease) as described above. These lubricants are supplied and sealed in the space between the inner and outer rings, and lubricated by being interposed in the rolling surface.

Lubricating oil can be used without particular limitation as long as it is normally used for angular ball bearings. For example, mineral oils such as paraffinic mineral oils and naphthenic mineral oils, hydrocarbon-based synthetic oils such as polybutene oils, poly-α-olefin oils, alkylbenzene oils and alkylnaphthalene oils, or natural oils and fats, polyol ester oils, phosphate ester oils And non-hydrocarbon synthetic oils such as diester oil, polyglycol oil, silicone oil, polyphenyl ether oil, alkyl diphenyl ether oil, and fluorine oil. These lubricating oils may be used alone or in combination of two or more.

When using grease as a lubricant, the above-mentioned lubricating oil can be used as the base oil constituting the grease. Further, as the thickening agent constituting the grease, for example, a metallic soap thickener such as aluminum soap, lithium soap, sodium soap, composite lithium soap, composite calcium soap, composite aluminum soap, diurea compound (aliphatic, fatty acid). Cyclic, aromatic diurea, etc.), urea compounds such as polyurea compounds, and fluororesin powders such as PTFE resins. These thickeners may be used alone or in combination of two or more.

Lubricants can be added with known additives as required. Examples of additives include extreme pressure agents such as organic zinc compounds and organic molybdenum compounds, antioxidants such as amine-based, phenol-based and sulfur-based compounds, anti-wear agents such as sulfur-based and phosphorus-based compounds, and polyhydric alcohols. Examples include rust preventives such as esters, viscosity index improvers such as polymethacrylate and polystyrene, solid lubricants such as molybdenum disulfide and graphite, and oily agents such as esters and alcohols.

Lubricant types (low-viscosity oil, alicyclic / aromatic urea thickener, etc.) corresponding to this are used for lubrication on the guide surface of angular ball bearings rotating at high speed. On the other hand, in the angular contact ball bearing of the present invention, a flocked portion is formed on the cage guide surface, and the lubricant is held in the flocked portion. Lubrication characteristics at the cage guide surface can be improved without significant dependence. In particular, in addition to the configuration in which the flocked portion is provided, the use of a lubricant suitable for a known angular ball bearing can further improve the lubrication characteristics and prevent the generation of abnormal noise.

The angular contact ball bearing of the present invention has excellent lubrication characteristics on the guide surface of the cage and can suppress the occurrence of abnormal noise by simple means even when existing bearing shapes and lubricants are used. Can be used for angular contact ball bearings in applications. In particular, it can be suitably used as an angular ball bearing that supports the spindle of a machine tool that rotates at high speed.

DESCRIPTION OF SYMBOLS 1 Angular contact ball bearing 2 Inner ring 3 Outer ring 4 Ball 5 Cage 6 Flocking part 7 Seal member 8 Grease

Claims

This is an angular ball bearing that includes inner and outer rings that are raceways, a plurality of balls that are interposed between the inner and outer rings, and a cage that holds the balls. And
The retainer is guided by the outer ring or the inner ring, and has a flocking portion formed by flocking fibers on at least a guide surface of the retainer.
The angular ball bearing according to claim 1, wherein the cage is guided by the outer ring, and the flocked portion is provided on an outer ring guide surface of the cage.
The angular ball bearing according to claim 1, wherein the cage is a resin cage made of a synthetic resin.
The angular ball bearing according to claim 1, wherein the fiber is a synthetic resin fiber, and the flocked portion is an electrostatic flocked portion.
The angular ball bearing according to claim 1, wherein the flocked portion is provided continuously up to a width surface of the cage.
The angular ball bearing according to claim 1, wherein the lubricant is held in the flocked portion.