JP2017057989A - Angular ball bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular ball bearing having a seal structure capable of preventing intrusion of a coolant liquid and foreign matters from the external with a simple structure disposed inside of the bearing.SOLUTION: An angular ball bearing 1, which supports a machine tool main spindle and the like, includes an inner ring 2 and an outer ring 3 as raceway rings, a plurality of balls 4 disposed between the inner and outer rings, a cage 5 for retaining the balls 4, and a seal member 7. The seal member 7 is fixed to the outer ring 3 at its one end portion, has a clearance with respect to the inner ring 2, and has a bristle-implanted portion 6 formed by implanting fiber, on at least one region selected from an inner diameter portion 7c and a bearing outer end face 7d of the seal member 7.SELECTED DRAWING: Figure 4

Description

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

  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.

  Further, in a machine tool, a coolant liquid is supplied to the processing object and the blade in order to lubricate and cool the processing object and the blade 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.

  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 roller bearing with a seal that prevents heat generation due to contact between an inner ring seal groove and a seal lip. As shown in FIG. 5, this rolling bearing 11 includes an inner ring 12, an outer ring 13, a ball 14, and a cage 15, and a pair of seals 16, 16 that seal the end of the bearing space between the inner and outer rings are provided as an outer ring. The seal lip 16a of the seal 16 is positioned in the annular inner ring seal groove 12a provided on the outer diameter surface of the inner ring 12, and the inner ring end face of the inner ring seal groove 12a is fitted. The distance between the inner side surface on the 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.

  In addition, a spindle configuration is known in which incidental equipment is provided and air purge is performed to ensure sealing. In this method, air is blown out to prevent the coolant liquid and foreign matter from entering. In particular, the pressure inside the spindle is made higher than the outside so as to prevent the intrusion of the coolant or foreign matter, so that the seal can be made more reliable.

JP 2008-101631 A

  However, the technology that implemented air purge requires an air supply device as ancillary equipment, reduces air consumption, maintains high cleanliness of the supplied air, and removes moisture in order to reduce environmental impact. It is necessary to manage continuously. For this reason, it is not suitable for the case where such management is difficult or for a general-purpose spindle that places importance on cost.

  Further, as described above, even if there is a contrivance of the seal structure such as these incidental facilities, there is a possibility that the coolant liquid or the foreign matter may enter. In the case of a non-contact seal having a gap (clearance) between the seal and the inner ring as in Patent Document 1, it is not possible to sufficiently prevent the coolant liquid or foreign matter from entering the bearing depending on the use conditions. . Improvement of the seal structure of the bearing itself is also desired in order to prevent the coolant liquid and foreign matter from entering the final bearing more reliably.

  The present invention has been made to cope with such problems, and provides an angular contact ball bearing having a seal structure capable of preventing entry of coolant liquid and foreign matters from the outside while being a simple structure provided inside the bearing. The purpose is to do.

  The angular ball bearing of the present invention is an angular ball bearing comprising an inner ring and an outer ring which are raceways, a plurality of balls interposed between the inner and outer rings, a cage for holding the balls, and a seal member. The seal member has one end fixed to the outer ring, has a gap with the inner ring, and implants fibers in at least one part selected from the inner diameter part of the seal member and the bearing outer end surface. It has the hair transplant part formed.

  The said hair transplant part is comprised from the multiple types of fiber from which fiber length differs. Moreover, the said hair transplant part is comprised from the fiber of the same fiber length as the said clearance gap, and the fiber of fiber length shorter than the said clearance gap, It is characterized by the above-mentioned.

  The flocked portion is formed on an inner diameter portion of the seal member and a bearing outer end surface, and the flocked portion on the inner diameter portion and the flocked portion on the end surface are discontinuous.

  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 which are raceways, a plurality of balls interposed between the inner and outer rings, a cage for holding the balls, and a seal member. Is a flocked product in which one end is fixed to the outer ring, a gap is formed between the inner ring, and fibers are implanted in at least one portion selected from the inner diameter portion (seal lip) of the seal member and the outer end surface of the bearing. Therefore, when used in a machine tool or the like, it is possible to prevent or suppress the entry of coolant liquid or foreign matter from the outside of the bearing with a simple structure without requiring any additional equipment.

  The flocked portion is composed of a plurality of types of fibers having different fiber lengths, for example, a fiber having the same fiber length as the gap and a fiber having a fiber length shorter than the gap. Intrusion of coolant and foreign matter can be further prevented while suppressing an increase in torque due to contact.

  Further, by providing the flocked portions on both the inner diameter portion of the seal member and the outer end surface of the bearing, the coolant liquid and foreign matter can be adsorbed on the seal end surface, and the intrusion into the bearing can be suppressed. Further, discontinuity of the flocked portion of the inner diameter portion and the flocked portion of the outer end surface of the bearing can suppress the intrusion of the coolant liquid through the seal end surface, the inner diameter of the seal, and the path inside the bearing.

  Moreover, since the said fiber is a synthetic resin fiber and the said flocked part is an electrostatic flocked part, it does not swell and melt | dissolve with oil, etc., is chemically stable, and becomes a homogeneous and dense flocked part.

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).

  One 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 (seal inner diameter portion) as an angular ball bearing of the present invention. The black arrows in the figure indicate the intrusion direction of the coolant and foreign matter from the outside of the bearing (the same applies to FIGS. 2 to 4). 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. On the outer diameter surface of the inner ring 2, a counter bore 2 b is provided on one side (left side in the drawing) of the raceway surface 2 a so that the outer diameter gradually decreases toward the outside. An annular seal groove 2c is provided on the shoulder on the opposite side of the raceway surface 2a. The angular ball bearing 1 is lubricated with grease sealed inside the bearing. The cage 5 is an outer ring guide system, and is guided to the outer ring 3 when the outer diameter surface of the cage 5 comes into contact with the inner diameter surface of the outer ring 3.

  The outer ring 3 is provided with a pair of annular seal members 7 and 7 at both axial ends of the outer ring 3 in order to seal the bearing space between the inner and outer rings. The seal member 7 is a composite composed of a cored bar 7a and an elastic member 7b such as a rubber molded body. One end of each of the seal members 7 is fixed to the outer ring 3, and a gap (clearance) is provided between the seal members 7 and the inner ring 2. Specifically, one seal member 7 (the left side in the figure) is disposed at the position of the counter bore 2b on the outer diameter surface of the inner ring 2 so that the inner diameter portion 7c thereof is not in contact with the inner ring 2. Further, the other seal member 7 (right side in the figure) is disposed in the seal groove 2 c of the inner ring 2 so that the inner diameter portion 7 c thereof is not in contact with the inner ring 2.

  A flocked portion 6 formed by flocking fibers is formed on the inner diameter portion 7 c of the seal member 7. In this form, the fiber length of the short fiber which comprises the hair transplant part 6 is single, and the length is made into the same grade as the said clearance gap. The fiber tip of the flocked portion 6 is in sliding contact with the counter bore 2b and the seal groove 2c of the inner ring 2, thereby sealing the gap between the seal member 7 and the inner ring 2. Thereby, without changing the structure of the existing seal member, the sealing performance can be improved, and the intrusion of the coolant or foreign matter from the outside of the bearing can be prevented or suppressed.

  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 contact ball bearing having a flocked portion (bearing outer end surface) as an angular contact ball bearing of the present invention. In the angular ball bearing 1 of the form shown in FIG. 2, the flocked portion 6 is formed on the bearing outer end surface 7 d of the seal member 7. In this embodiment, no flocked portion is formed on the inner diameter portion of the seal member 7. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

  Since the coolant liquid and foreign matter before reaching the seal lip can be adsorbed by the flocked portion 6 of the bearing outer end surface 7d, the penetration into these bearings can be suppressed. Further, the bearing outer end surface 7d on which the flocked portion 6 is formed has less interference with other members than the inner diameter portion, and the inner ring rotary bearing is not subjected to centrifugal force, so that the flocked portion is less likely to drop off. The above effects can be expected stably over a long period of time.

  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 (seal inner diameter portion) as the angular ball bearing of the present invention. In the angular ball bearing 1 of the form shown in FIG. 3, the flocked portion 6 is formed on the inner diameter portion 7 c of the seal member 7 as in FIG. 1. 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.

  The flocked portion 6 formed in the inner diameter portion 7c of the seal member 7 has the fiber tip in sliding contact with the counter bore of the inner ring 2 and the seal groove in order to seal the gap between the seal member 7 and the inner ring 2. 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 the gap, the contact becomes light contact, and an increase in torque can be prevented. In the form of FIG. 3, as the short fibers forming the flocked portion 6, the fibers having the same fiber length as the gap and the fibers having a fiber length shorter than the gap are used, so that the short fiber is shorter than the inner ring 2. Are not in contact with each other, and long fibers are light in contact with each other, 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. 4 is a partial cross-sectional view of an angular ball bearing having a flocked portion (a seal inner diameter portion and a bearing outer end surface) as an angular ball bearing of the present invention. In the angular ball bearing 1 of the form shown in FIG. 4, the flocked portion 6 is formed on the inner diameter portion 7c of the seal member 7 as in FIG. 1, and the flocked portion 6 is formed on the bearing outer end surface 7d of the seal member 7 as in FIG. Forming. The other overall configuration is the same as that of the angular ball bearing of the form shown in FIG.

  In this embodiment, the combination of the flocked portions shown in FIGS. 1 and 2 can further prevent the coolant liquid and foreign matter from entering the bearing. Here, in the seal member 7, when the flocked portion of the inner diameter portion 7 c and the flocked portion of the bearing outer end surface 7 d are continuously formed, the seal end surface, the inner diameter of the seal, and the inside of the bearing are transmitted through the flocked portion. There is a risk of coolant entering the path. For this reason, it is preferable that these flocked parts are not continuous.

  The forms shown in FIGS. 1 to 4 can be applied in appropriate combination. Moreover, in the form of FIGS. 1-4, the flocked part 6 is good also as a form formed not in the whole surface of each of the internal diameter part 7c and the bearing outer end surface 7d but in part. Further, the structure of the seal member is not limited to the illustrated example, and may be a shield made of a plate-shaped metal plate, a rubber molded body alone, a composite of a rubber molded body and a plastic plate, or a ceramic plate.

  The cage 5 is a resin-made machined cage, and pocket portions for holding balls as rolling elements are provided at regular intervals in the circumferential direction on an annular cage body. 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.

  Moreover, although the case of the resin-made cage was demonstrated about the cage, it is not limited to this in the angular ball bearing of this invention, Arbitrary materials, such as a metal material, are employable. 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. As a specific shape, for example, those having a length of 0.5 to 2.0 mm and a thickness of 0.5 to 50 dtex are preferable, 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 in which the tip is bent), and both 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, acrylate-vinyl acetate copolymer emulsion adhesive, vinyl acetate emulsion adhesive , Urethane resin emulsion adhesive, epoxy resin emulsion adhesive, polyester emulsion adhesive, ethylene-vinyl acetate copolymer adhesive 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 (mainly grease). These lubricants are 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 according to the present invention, the flocked portion is formed on the seal member as described above. Therefore, particularly when formed on the inner diameter portion, the seal member has a high sealing performance against foreign matters from the outside, and at the same time, high against leakage of grease inside the bearing. Also has sealing properties. Therefore, for example, even when a low-viscosity base oil or a grease having a high miscibility is used for torque reduction, leakage of the grease or base oil can be prevented. For this reason, various greases can be widely used.

  Although the angular ball bearing of the present invention has a simple structure provided inside the bearing, it has a seal structure that can prevent entry of coolant liquid and foreign matters from the outside, and therefore can be used for angular ball bearings in various applications. In particular, it can be suitably used as an angular ball bearing that supports a spindle of a machine tool that is used at high speed and is likely to be mixed with coolant or foreign matter.

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

Claims (5)

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, a cage that holds the balls, and a seal member,
The seal member has one end fixed to the outer ring, has a gap with the inner ring, and is formed by implanting fibers in at least one portion selected from an inner diameter portion of the seal member and a bearing outer end surface. An angular contact ball bearing having a flocked portion.   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 2, wherein the flocked portion is composed of fibers having the same fiber length as the gap and fibers having a fiber length shorter than the gap.   The said hair transplant part is formed in the internal diameter part of the said sealing member, and a bearing outer end surface, The hair transplant part of the said internal diameter part and the hair transplant part of the said end surface are discontinuous from Claim 1 to Claim 3 characterized by the above-mentioned. The angular ball bearing according to any one of the above.   The angular contact ball bearing according to any one of claims 1 to 4, wherein the fiber is a synthetic resin fiber, and the flocked portion is an electrostatic flocked portion.

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