WO2017047772A1

WO2017047772A1 - Angular contact ball bearing

Info

Publication number: WO2017047772A1
Application number: PCT/JP2016/077500
Authority: WO
Inventors: 裕士恩田
Original assignee: Ntn株式会社
Priority date: 2015-09-18
Filing date: 2016-09-16
Publication date: 2017-03-23
Also published as: JP2017057986A

Abstract

Provided is an angular contact ball bearing that does not require space in the width direction of a bearing for a seal, that makes it possible to increase load capacity, and that is capable of minimizing the entry of coolant liquid and foreign matter. The angular contact ball bearing 1 supports a machine tool main shaft or the like and is provided with: an inner ring 2 and an outer ring 3 that are bearing rings; a plurality of balls 4 interposed between the inner and the outer rings; and a holder 5 for holding the balls 4. The outer diameter surface 5a of the holder 5 and an outer diameter surface 2a of the inner ring 2 that faces the inner diameter surface 5b of the holder 5 comprise a bristle section 6 in which fibers are implanted as bristles. The bristle sections 6 seal the gap between the outer ring 3 and the holder 5 and the gap between the inner ring 2 and the holder 5.

Description

Angular contact ball bearings

The present invention relates to an angular ball bearing used for supporting a spindle of a machine tool.

Among rolling bearings, angular ball bearings can receive a combined load composed of a radial load and a relatively large axial load. For this reason, it is often used for applications such as machine tools, medical equipment, construction machines, and agricultural machines that require high-speed rotation even under environments with heavy loads and various load directions. 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.

Also, in machine tools, coolant is supplied to the workpiece and the cutting tool in order to lubricate and cool the workpiece and the cutting tool during cutting. At this time, if coolant liquid or foreign matter enters the angular ball bearing that supports the spindle of the machine tool, it may affect bearing lubrication and cause bearing seizure. In order to prevent coolant liquid and foreign matter from entering the main shaft, the seal structure at the front end of the main shaft has been devised, but it may still enter the bearing and cause problems.

For this reason, various seal structures are adopted for angular ball bearings. Angular ball bearings that support high-speed operation spindles, such as machine tool spindles, generate a large amount of heat during high-speed operation and increase rotational torque. Therefore, the seal structure is often a non-contact type.

For example, Patent Document 1 proposes a sealed angular contact ball bearing that prevents heat generation due to contact between an inner ring seal groove and a seal lip. As shown in FIG. 5, the angular ball bearing 11 includes an inner ring 12, an outer ring 13, a ball 14, and a cage 15, and includes a pair of

seals

16 and 16 that seal the end of the bearing space between the inner and outer rings. The seal lip 16a of the seal 16 is fitted in a seal mounting groove provided in the outer ring 13, and the inner ring 12 of the inner ring seal groove 12a is positioned in the annular inner ring seal groove 12a provided on the outer diameter surface of the inner ring 12. The distance between the inner surface on the end surface side and the side surface of the seal lip 16a is a distance at which the seal lip 16a and the inner ring seal groove 12a are held in a non-contact manner.

Also known is an angular ball bearing having a structure without a seal member. An angular ball bearing 21 shown in FIG. 6 includes an inner ring 22, an outer ring 23, and a ball 24, and the ball 24 is held by a T-shaped cage 25. The flange portion 25a of the cage 25 is arranged on the wide opening side (counter bore side) of the angular ball bearing to suppress the entry of coolant liquid or foreign matter into the rolling portion.

JP 2008-101631 A

However, the angular contact ball bearing with seal shown in FIG. 5 and the angular contact ball bearing having the T-shaped cage shown in FIG. 6 have a space limitation in the bearing width direction, and the ball (ball) is small or the load capacity is increased. There are disadvantages such as being unable to let Further, the T-type cage tends to collect grease near the ball. If grease accumulates excessively in the vicinity of the ball, it takes time for the break-in operation, and there is a possibility of rapid temperature rise or burning due to re-engagement of grease during operation.

The present invention has been made to cope with such problems, and does not require a space in the bearing width direction for the seal, can increase the load capacity, and can prevent the entry of coolant liquid or foreign matter. An object of the present invention is to provide an angular ball bearing that can be suppressed.

An angular contact ball bearing according to the present invention is an angular contact ball bearing comprising an inner ring and an outer ring that are raceways, a plurality of balls interposed between the inner and outer rings, and a cage that holds the balls. At least one of the outer diameter surface of the cage and the inner diameter surface of the outer ring facing the outer diameter surface, and at least one of the inner diameter surface of the cage and the outer diameter surface of the inner ring facing the inner diameter surface And having a flocked portion formed by flocking fibers.

The angular ball bearing is an inner ring rotary bearing, and the flocked portion is formed on the outer diameter surface of the cage and the outer diameter surface of the inner ring.

The inner ring or the outer ring is provided with a counter bore on one side of the raceway groove, and the flocked portion is formed at an axial position on the counter bore side with respect to the ball in each member. Moreover, the said hair transplant part is formed in the width surface of the said holder | retainer, It is characterized by the above-mentioned.

The above-described flocked portion is composed of a plurality of types of fibers having different fiber lengths. Further, the fiber is a synthetic resin fiber, and the flocked portion is an electrostatic flocked portion.

The angular ball bearing of the present invention comprises an inner ring and an outer ring that are raceways, a plurality of balls interposed between the inner and outer rings, and a cage that holds the balls. (1) At least one of an outer diameter surface and an inner diameter surface of the outer ring facing the outer diameter surface; and (2) at least one of the inner diameter surface of the cage and the outer diameter surface of the inner ring facing the inner diameter surface. Since it has a flocked part that is formed by flocking fibers, it can be sealed without the need for space in the bearing width direction for sealing, is not subject to ball size restrictions, and is an angular ball with a seal or using a T-type cage The load capacity of the bearing can be increased as compared with the bearing. Moreover, the penetration | invasion to the rolling part of coolant liquid or a foreign material can be suppressed. As a result, the bearing has a high reliability and a long life.

This angular ball bearing is an inner ring rotary bearing, and the flocked portion is formed on the outer diameter surface of the cage and the outer diameter surface of the inner ring. It is possible to suppress the coolant liquid and foreign matter from entering the rolling portion from the gap between the vessels or the gap between the inner ring and the cage.

The inner ring or the outer ring is provided with a counter bore on one side of the raceway groove, and the flocked portion is formed at an axial position on the counter bore side with respect to the ball in each member. Can seal the wide opening side. In addition, since the flocked portion is also formed on the width surface of the cage, the area of the flocked portion is widened, so that more coolant liquid and foreign matter entering from the outside of the bearing can be adsorbed, and the intrusion into these rolling portions Can be suppressed.

The flocked portion is composed of a plurality of types of fibers having different fiber lengths. For example, the fibers having the same fiber length and the short fiber length with respect to the gap between the outer ring and the cage and the gap between the inner ring and the cage. Therefore, it is possible to suppress an increase in torque due to contact between the fiber and the outer ring / retainer, and to suppress the intrusion of the coolant liquid or the foreign matter.

Since the fiber is a synthetic resin fiber and the flocked portion is an electrostatic flocked portion, swelling and dissolution due to oil hardly occur and it is chemically stable and becomes a homogeneous and dense flocked portion.

It is a partial sectional view of an angular contact ball bearing concerning an example 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 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 cross section figure of the conventional angular contact ball bearing (non-contact seal). It is a partial cross section figure of the conventional angular contact ball bearing (T type cage).

An embodiment of the angular ball bearing of the present invention will be described with reference to FIG. FIG. 1 is a partial cross-sectional view of an angular ball bearing having a flocked portion (cage outer diameter surface, inner ring outer diameter surface) as an angular ball bearing of the present invention. 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. The cage 5 is a resin-made machined cage, and pocket portions for holding the balls 4 are provided at regular intervals in the circumferential direction in an annular cage body. On the inner diameter surface 3 a of the outer ring 3, a counter bore whose inner diameter is gradually increased outward is provided on one side (right side in the drawing) of the raceway groove. In the present embodiment, the counter bore having only the outer ring is described, but the same applies to the case where the inner ring is provided with the counter bore. The cage 5 is an outer ring guide system, and is guided to the outer ring 3 by a part of the outer diameter surface (left side in the figure) of the cage 5 coming into contact with the inner diameter surface of the outer ring 3.

This angular ball bearing 1 is an inner ring rotary bearing in which an outer ring 3 is fixed to a housing or the like, and an inner ring 2 rotates together with a support target member such as a machine tool main shaft. Further, the angular ball bearing 1 does not use a seal member. The type of lubrication 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 formed by enclosing grease.

In the angular ball bearing 1 of FIG. 1, fibers are applied to (1) the outer diameter surface 5a of the cage 5 and (2) the portion of the outer diameter surface 2a of the inner ring 2 that faces the inner diameter surface 5b of the cage 5. A flocked portion 6 formed by flocking is formed. For (1), in more detail, the flocked portion 6 is formed on the collar portion (ring portion) of the cage 5, which is the portion facing the non-orbital portion of the outer ring 3, of the outer diameter surface 5 a of the cage 5. Has been. Regarding (2), in more detail, the flocked portion 6 is formed in a portion of the outer diameter surface 2 a of the inner ring 2 that faces the inner diameter surface 5 b of the collar portion (ring portion) of the cage 5. Further, the flocked portions 6 of (1) and (2) are arranged at the same position in the axial direction on the counterbore side. In addition, all the hair transplant parts of (1) and (2) are formed continuously or intermittently in the circumferential direction.

In this embodiment, the short fibers constituting the flocked portion 6 have a single fiber length, and the length is approximately the same as the gap (clearance) between the members at the formation locations. The flocked portion 6 expands in the outer diameter direction due to the centrifugal force during rotation of the bearing, the flocked portion 6 in (1) passes through the gap between the outer ring 3 and the cage 5, and the flocked portion 6 in (2) Each gap with the cage 5 is sealed. Thereby, it can suppress that coolant liquid and a foreign material penetrate | invade into a rolling part from each wide clearance gap at the counterbore side. Further, since the seal member is not provided inside the bearing and the existing shape of the cage can be used as it is, a space in the bearing width direction for sealing is not required. For this reason, the size of the ball 4 can be increased, and the load capacity of the bearing can be increased.

Another embodiment of the angular ball bearing of the present invention will be described with reference to FIG. FIG. 2 is a partial cross-sectional view of an angular ball bearing having a flocked portion (cage outer diameter surface, inner ring outer diameter surface) as an angular ball bearing of the present invention. In the angular ball bearing 1 of the form shown in FIG. 2, as in FIG. 1, (1) the outer diameter surface 5a of the cage 5 and (2) the inner diameter surface of the cage 5 among the outer diameter surfaces 2a of the inner ring 2. A flocked portion 6 formed by flocking fibers is formed in a portion facing 5b. In this embodiment, a plurality of types of fibers having different fiber lengths are used as the short fibers that form the flocked portion 6. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

(1) The flocked portion 6 has its fiber tip in sliding contact with the inner diameter surface 3 a of the outer ring 3, and the (2) flocked portion 6 has its fiber tip in sliding contact with the inner diameter surface 5 b of the cage 5. Since this sliding contact increases torque and heat generation, it is necessary to suppress this. For example, by adjusting the fiber length so that it is about the same as each gap, the contact becomes light contact, and an increase in torque can be prevented. In the form of FIG. 2, as the short fibers forming the flocked portion 6, the outer ring 3 and the cage 5 are used by using fibers having the same fiber length as the gaps and fibers having a fiber length shorter than the gaps. On the other hand, short fibers do not contact, and long fibers become light contact, and an increase in torque and heat generation can be suppressed. Moreover, it has sufficient sealing property by the flocking structure which combined these.

Another embodiment of the angular ball bearing of the present invention will be described with reference to FIG. FIG. 3 is a partial cross-sectional view of an angular ball bearing having a flocked portion (outer ring inner diameter surface, cage outer diameter surface, cage inner diameter surface, inner ring outer diameter surface) as an angular ball bearing of the present invention. In the angular ball bearing 1 of the form shown in FIG. 3, in addition to (1) and (2) similar to FIG. 1, (3) Of the inner diameter surface 3a of the outer ring 3, it faces the outer diameter surface 5a of the cage 5. And (4) a flocked portion 6 formed by flocking fibers is formed on the inner diameter surface 5 b of the cage 5. Regarding (3), in more detail, the flocked portion 6 is formed in a portion of the inner diameter surface 3 a of the outer ring 3 that faces the outer diameter surface 5 a of the collar portion (ring portion) of the cage 5. Regarding (4), in more detail, the flocked portion 6 is formed on the collar portion (ring portion) of the cage 5 which is a portion of the inner diameter surface 5 b of the cage 5 that faces the non-orbital portion of the inner ring 2. ing. Moreover, the hair transplant part 6 of (3) and (4) is also arrange | positioned in the axial direction same position by the side of a counterbore similarly to the hair transplant part 6 of (1) and (2). In addition, all the flocked parts of (3) and (4) are formed continuously or intermittently in the circumferential direction. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

In this form, the fiber length of the short fiber which comprises the flocked part 6 is single, The length is made into the clearance gap (about half or less of clearance. The fiber front-end | tips are made to lightly contact each other. The gap between the outer ring 3 and the retainer 5 is formed by the flocked part 6 of (1) and (3), and the gap between the inner ring 2 and the retainer 5 is formed by the flocked part 6 of (2) and (4). In this configuration, the bearing rotational speed is low, and when the flocked fiber cannot be expected to spread due to centrifugal force, or when the bearing is stationary, the coolant and foreign matter are prevented from entering the rolling part from each gap. it can.

Another embodiment of the angular ball bearing of the present invention will be described with reference to FIG. FIG. 4 is a partial sectional view of an angular ball bearing having a flocking portion (outer ring inner diameter surface, cage outer diameter surface, cage inner diameter surface, inner ring outer diameter surface, cage width surface) as an angular ball bearing of the present invention. is there. In the angular ball bearing 1 of the form shown in FIG. 4, in addition to (1) to (4) similar to FIG. 4, (5) a flocked portion 6 formed by flocking fibers is formed on the width surface 5c of the cage 5. Has been. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

In this form, since the flocked part 6 is also formed on the width surface 5c of the cage 5, the formation region of the flocked part 6 is widened, and more adsorbed coolant liquid and foreign matters that are about to enter from the outside of the bearing, Intrusion into these rolling parts can be suppressed.

1 to 4 can be applied in appropriate combination. 1 to 4, the flocked portion may be formed not only on the counter bore side but also on the opposite side. For example, in the form shown in FIG. 1, a flocked portion that seals the gap between the inner ring 2 and the cage 5 on the opposite side in the axial direction may be formed.

The resin cage 5 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 resin base 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.

Further, although the case of the resin cage has been described as the cage, the angular ball bearing of the present invention is not limited to this, and any material such as a metal material can be adopted. Further, the cage type is not particularly limited, and may be a crown-shaped cage or a waveform cage.

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. In addition, electrostatic spraying (fiber coating) can also be employed.

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 fiber (short fiber) is not particularly limited as long as it does not interfere with other members that adversely affect the bearing function at the place where the flocked portion is formed. 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 the fibers in the flocked portion is the ratio of the fibers to the flocked area Is preferably 1 to 40%. As the shape of the short fiber, there are a straight and a bend (a shape where the tip is bent), and any of them can be used. Moreover, there exist circular shape and polygonal shape as a cross-sectional shape of a short fiber, and any can be used.

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 (lubricating oil or grease). These lubricants are supplied and sealed in the bearing space between the inner and outer rings, and lubricated by being interposed in the rolling surface. Any lubricating oil or grease can be used without particular limitation as long as it is normally used for an angular ball bearing.

In the rolling bearing of the present invention, since the flocked portion as described above is formed, it is easy to fasten the lubricant to the rolling portion. Therefore, for example, even when a low-viscosity base oil or a grease with a high miscibility is used to reduce torque, leakage of the grease or base oil can be suppressed. For this reason, various greases can be widely used.

The angular contact ball bearing of the present invention does not require a space in the bearing width direction for sealing, can increase the load capacity, and can suppress the intrusion of coolant liquid or foreign matter. Available for bearings. In particular, it can be suitably used as an angular ball bearing that supports the spindle of a machine tool.

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

Claims

An angular ball bearing comprising an inner ring and an outer ring that are raceways, a plurality of balls interposed between the inner and outer rings, and a cage that holds the balls,
At least one of the outer diameter surface of the cage and the inner diameter surface of the outer ring facing the outer diameter surface, and at least one of the inner diameter surface of the cage and the outer diameter surface of the inner ring facing the inner diameter surface An angular ball bearing characterized by having a flocked portion formed by flocking fibers.
The angular ball bearing is an inner ring rotary bearing,
2. The angular ball bearing according to claim 1, wherein the flocked portion is formed on an outer diameter surface of the cage and an outer diameter surface of the inner ring.
The inner ring or the outer ring is provided with a counter bore on one side of the raceway groove,
The angular ball bearing according to claim 1, wherein the flocked portion is formed at an axial position on the counter bore side with respect to the ball in each member.
2. The angular ball bearing according to claim 1, wherein the flocked portion is formed on a width surface of the cage.
The angular ball bearing according to claim 1, wherein the flocked portion is composed of a plurality of types of fibers having different fiber lengths.
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.