JP2008240776A - Angular contact ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular contact ball bearing suppressing heat generation by suppressing stirring resistance accompanying the movement of grease at an initial stage of use and enhancing lubrication reliability, in a retainer outer ring guide type angular contact ball bearing in which a grease reservoir is provided on an inner diameter surface of the outer ring. <P>SOLUTION: An outer ring grease reservoir groove 6m recessed to an outer side in a radial direction is formed on an inner peripheral surface of the outer ring 6, and a through-hole 11 communicated from an outer ring chamfered part 6r with the outer ring grease reservoir groove 6m is formed on the outer ring 6. The grease is filled in the outer ring grease reservoir groove 6m from the through-hole 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a grease-lubricated angular ball bearing suitably applied to, for example, a main shaft of a machine tool.

A conventional rolling bearing will be described with reference to FIG. Grease-lubricated angular ball bearings are put to practical use. For example, an outer ring guide type cage 1 is applied to this angular ball bearing. Some grease lubricated angular ball bearings are provided with a seal 2 for sealing the bearing space between the inner and outer rings in order to retain a large amount of grease. Furthermore, the present applicant has put into practical use an angular ball bearing, a so-called BNS series, in which a grease reservoir is formed in the vicinity of the raceway surface of the outer ring and the amount of grease filled is increased (for example, Non-Patent Document 1). The BNS series angular contact ball bearings have a longer life than standard angular contact ball bearings.
NTN Corporation precision rolling bearing CAT. No. 2260-II / J 04.09.03 (page 57, figure 9.8) JP 2003-227525 A

In the conventional angular ball bearing, since the cage 1 is an outer ring guide, the gap between the outer ring 4 and the cage 1 is narrow, and the grease reservoir 4b cannot be directly filled with grease from outside the bearing. For this reason, grease is sealed from the inner diameter side of the cage 1. In this case, in order to spread the grease enclosed in the inner diameter surface Hm of the cage to the raceway surfaces 3a and 4a of the inner and outer rings 3 and 4, a so-called running-in operation is performed at the time of shipment of the angular ball bearing and after the customer is assembled (for example, Patent Document 1). The grease is agitated by the running-in operation and moves to a stationary space including the grease reservoir 4 b of the outer ring 4. There is a problem that heat is generated by stirring resistance during the grease movement.
It is also conceivable to provide a grease supply device for supplying grease to the outer ring inner peripheral surface of the angular ball bearing in the housing in which the angular ball bearing is fitted. In this case, however, the structure becomes complicated and the overall structure is undesirable. To make it larger. In addition, there is a problem that the manufacturing cost is increased due to the introduction of the grease supply device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cage outer ring guide type angular contact ball bearing with a grease reservoir on the inner surface of the outer ring. It is to provide a ball bearing.

  The angular ball bearing of the present invention is an angular ball bearing in which a ball held by a cage is interposed between an inner ring and an outer ring, and a bearing space between the inner ring and the outer ring is sealed with a seal. An outer ring grease retaining groove that is recessed radially outward is formed on the inner peripheral surface of the outer ring, and is guided from the outer ring chamfered portion between the outer diameter surface and the end surface of the outer ring. A through hole communicating with the outer ring grease reservoir groove is formed in the outer ring, and grease is sealed from the through hole into the outer ring grease reservoir groove.

  According to this configuration, the outer ring grease retaining groove that is recessed radially outward is formed on the inner peripheral surface of the outer ring, and a through hole that communicates with the outer ring grease retaining groove from the outer ring chamfered portion is formed in the outer ring. Since the outer ring grease reservoir groove is filled with grease, the grease can be easily enclosed in the grease reservoir while being a cage outer ring guide type. Therefore, compared with the prior art that moves the grease from the inner diameter of the cage to a stationary space including the grease reservoir of the outer ring, it is possible to suppress heat generation by suppressing the stirring resistance associated with the grease movement in the initial stage of use. Thereby, deterioration of grease can be prevented and the bearing life can be extended. Therefore, it is possible to realize an angular ball bearing in which the stirring resistance associated with grease movement is suppressed and the heat generation is suppressed and the lubrication reliability is improved as compared with the prior art.

  In addition, the number of types of grease in the applicable operating temperature range can be increased and the degree of freedom in bearing design can be increased. Further, since the through hole is formed so as to communicate with the outer ring grease retaining groove from the outer ring chamfered portion instead of the outer ring outer diameter surface or end surface, the dimensional accuracy of the outer ring outer diameter surface or end surface can be maintained within a predetermined range. It becomes. Therefore, this angular ball bearing can be applied to a highly accurate bearing required such as a machine tool bearing.

In this invention, it is preferable that the outer ring grease retaining groove is formed between the outer ring raceway surface of the outer peripheral surface of the outer ring and the outer ring guide surface guided by the outer diameter surface of the cage. In this case, the grease sealed in the outer ring grease reservoir groove can be smoothly guided to the outer ring raceway surface and the outer ring guide surface.
In this invention, it is preferable to provide the outer ring with a stopper plug that closes the through hole. In this case, it is possible to reliably prevent the grease sealed at one end from leaking from the outer ring chamfered portion.

  In the present invention, the through holes of the outer ring may be provided at a plurality of locations in the circumferential direction. The larger the number of through-holes in the circumferential direction of the outer ring, the more grease can be sealed in the circumferential direction of the grease reservoir from these through-holes, and the cage is moved from the inner diameter of the cage to a stationary space including the grease reservoir in the outer ring. The running-in time can be shortened compared to the conventional method.

  In the angular ball bearing of the present invention, the cage is guided on the inner peripheral surface of the outer ring, and an outer ring grease retaining groove that is recessed radially outward is formed on the inner peripheral surface of the outer ring. A through hole communicating with the outer ring grease reservoir groove from the outer ring chamfered portion between the surface and the end surface is formed in the outer ring, and grease is sealed into the outer ring grease reservoir groove from this through hole. However, it is possible to suppress the stirring resistance associated with the grease movement in the initial stage of use, thereby suppressing heat generation and improving the lubrication reliability.

  An embodiment of the present invention will be described with reference to FIGS. The angular ball bearing according to this embodiment is applied to, for example, a machine tool spindle. However, it is not limited to the machine tool spindle. In this angular ball bearing, a ball 7 is interposed between an inner ring 5 and an outer ring 6, and the bearing space between the inner ring 5 and the outer ring 6 is sealed with seals 8 and 8 and used for grease lubrication. The The seal 8 is a non-contact type seal that is attached to the seal groove 6 a of the outer ring 6 and whose inner diameter side end is close to the inner ring 5. The balls 7 are held by a cage 9 so as to roll freely at a predetermined interval in the circumferential direction. A raceway groove 5a and a raceway groove 6b are provided on the outer peripheral surface of the inner ring 5 and the inner peripheral surface of the outer ring 6 so that the contact angle with the ball 7 is a predetermined angle.

  The cage 9 is formed in a ring shape so that the wall thickness Hn is constant over the entire circumference. A cylindrical hole-shaped pocket Pt that holds the ball 7 in a rollable manner is formed at the center in the width direction of the cage 9. A plurality of pockets Pt are arranged at regular intervals in the circumferential direction. The cage 9 is made of, for example, a resin material or a metal cut-out product, and is guided to the inner peripheral surface of the outer ring 6. A corner chamfer 10 is applied to the corner between the inner diameter surface Hd1 of the cage and the end surface Ht of the cage. The portion of the inner peripheral surface of the outer ring 6 that guides the cage 9 that becomes the outer ring guide surface 6h, that is, the portion of the inner peripheral surface of the outer ring that is axially inward of the outer ring seal groove 6a is on both axial sides of the raceway groove 6b. In addition, the outer ring grease reservoir groove 6m is provided. The outer ring grease reservoir groove 6m is formed on the inner peripheral surface of the outer ring 6 in the vicinity of both sides in the axial direction of the raceway groove 6b so as to form an annular concave shape portion that is recessed radially outward from the outer ring guide surface 6h. . The outer circumferential surface of the outer ring 6 is cylindrical, and no so-called counter bore is provided.

Next, the through hole of the outer ring 6 will be described.
A through hole 11 is formed in the outer ring 6 so as to communicate with the outer ring grease retaining groove 6m from the outer ring chamfered portion 6r, and the grease Gr is sealed from the through hole 11 into the outer ring grease retaining groove 6m. In the present embodiment, a plurality of through holes 11 of the outer ring 6 are formed at regular intervals in the circumferential direction as shown in FIG. If the grease Gr is sealed while the cage 9 and the inner ring 5 are rotated, the grease can be more evenly distributed along the circumference. The outer ring chamfered portion 6r is a so-called round chamfer between the outer diameter surface 6D of the outer ring 6 and the end surface 6Hm, and has a size that does not interfere with a corner or a corner R of a housing (not shown) into which the outer ring 6 is fitted. It is formed in a round chamfered shape.

  The through-hole 11 has a large-diameter hole 11a provided with a stopper plug 12, and a small-diameter hole 11b concentric with the large-diameter hole 11a and having a smaller diameter than the large-diameter hole 11a. The large-diameter hole 11a is formed in the shape of a counterbore that is exposed outward in the radial direction. For example, a female screw or the like for screwing the stopper plug 12 is formed on the inner periphery of the large-diameter hole 11a. The stopper plug 12 is realized, for example, by a hexagon socket plug, a grease nipple, or the like, and is configured to be detachable from the female screw. Further, the distal end portion 12a facing outward of the stopper plug 12 is formed in the same round chamfered shape as the outer ring chamfered portion 6r in which the female screw is not formed, and does not interfere with the corner portion or the corner R of the housing. It is stipulated in. The stopper plug 12 may not be detachable.

  A plurality of through holes 11 on one end in the axial direction, that is, the right side of FIG. 1 and a plurality of through holes 11 on the other end in the axial direction, that is, the left side in FIG. That is, they are formed at the same left and right positions so as not to have a staggered arrangement in FIG. Each through hole 11 is a so-called straight hole having an inclination angle α toward the axial center of the outer ring 6, that is, the center in the width direction, from the outer ring chamfered portion 6r toward the outer ring grease retaining groove 6m. The inclination angle α is set to, for example, about 60 degrees with respect to the bearing axis L1.

  The portion of the small diameter hole 11b exposed radially inward of each through hole 11 of the outer ring 6 opens to the annular corner 6mr adjacent to the outer ring guide surface 6h of the outer ring grease reservoir groove 6m. The annular corner portion 6mr of the outer ring grease retaining groove 6m forms a corner R having a curvature center at a position slightly in the center in the width direction from the outer ring guide surface 6h and radially inward from the outer ring grease retaining groove 6m. The intersecting portion, that is, the corner portion between the annular corner portion 6mr and the outer ring guide surface 6h is formed so as not to be sharp.

  On the outer peripheral surface of the inner ring 5, a counter bore 5 b is provided on one side of the raceway groove 5 a, the outer diameter of which gradually becomes smaller toward the end surface. The counter bore 5b is provided on a portion of the outer peripheral surface opposite to the direction in which the contact angle occurs. At the time of assembling the bearing, this angular ball bearing heats the outer ring 6 on which the balls 7 are assembled, thereby expanding the outer ring 6 radially outward by a predetermined small distance, and axially extending the inner ring 5 from the counter bore 5b side. Can be assembled by inserting.

  According to the angular ball bearing according to the embodiment of the present invention described above, the outer ring guide type retainer 9 is provided, the outer ring 6 has an outer ring grease retaining groove 6m that is recessed radially outwardly on the inner circumferential surface of the outer ring 6, and the outer ring chamfer. A through hole 11 communicating with the outer ring grease retaining groove 6m from the portion 6r is formed in the outer ring 6, and the grease Gr is sealed from the through hole 11 into the outer ring grease retaining groove 6m. The grease Gr in the reservoir groove 6m can be easily sealed. Therefore, compared with the conventional technology in which the grease is moved from the inner diameter of the cage to the stationary space including the grease reservoir of the outer ring, the stirring associated with the movement of the grease in the initial stage of use. Heat can be suppressed by suppressing resistance. Thereby, deterioration of the grease Gr can be prevented and the bearing life can be extended. Therefore, it is possible to realize an angular ball bearing in which the stirring resistance associated with grease movement is suppressed and the heat generation is suppressed and the lubrication reliability is improved as compared with the prior art.

  In addition, the number of types of grease Gr in the applicable operating temperature range can be increased, and the degree of freedom in bearing design can be increased. Further, since the through hole 11 is formed so as to communicate with the outer ring grease retaining groove 6m from the outer ring chamfered portion 6r, not the outer ring outer diameter surface 6D and the outer ring end surface 6Hm, the dimensional accuracy of the outer ring outer diameter surface 6D and the outer ring end surface 6Hm. Can be maintained within a predetermined range. Therefore, this angular ball bearing can be applied to a highly accurate bearing required such as a machine tool bearing.

  Further, since the outer ring grease retaining groove 6m is formed between the outer ring raceway surface 6b and the outer ring guide surface 6h on the inner peripheral surface of the outer ring 6, the grease Gr enclosed in the outer ring grease retaining groove 6m is removed from the outer ring raceway surface 6b. And it can guide to the outer ring guide surface 6h smoothly. The grease Gr existing in the outer ring raceway surface 6b and the outer ring grease retaining groove 6m can be spread over the raceway surfaces 5a and 6b of the inner and outer rings 5 and 6 by rotating the cage 9 and the inner ring 5. The grease Gr guided to the outer ring guide surface 6h can prevent lubrication failure such as wear and seizure of the guide surface, and can suppress the generation of cage noise.

  The through-hole 11 of the outer ring 6 has an inclination angle α toward the center in the width direction from the outer ring chamfered portion 6r toward the outer ring grease collecting groove 6m, so that the end of the guide surface of the cage outer diameter Hd2 when grease is filled Grease Gr is less likely to be scattered from the side to the side. The bottom portion of the large-diameter hole 11a of the through hole 11 serves as a seating surface with which the base end portion 12b of the stopper plug 12 abuts, so that it is possible to further prevent the grease Gr from leaking outward from the through hole 11. .

  The annular corner 6mr of the outer ring grease retaining groove 6m forms a corner R having a curvature center at a position slightly in the center in the width direction from the outer ring guide surface 6h and radially inward of the outer ring grease retaining groove 6m. Sometimes the grease Gr can be easily and smoothly guided to the outer ring raceway surface 6b by centrifugal force radially outward from the cage outer diameter Hd2. Since the intersecting portion, that is, the corner portion between the annular corner portion 6mr and the outer ring guide surface 6h is formed so as not to be sharp, the guide surface can be reliably prevented from being worn or seized.

  Further, according to the angular ball bearing according to the present embodiment, it is only necessary to enclose the grease Gr from the through hole 11 into the outer ring grease reservoir groove 6m. Therefore, the overall structure can be reduced in size without being complicated. Since such a grease supply device is not introduced, the manufacturing cost can be reduced.

As another embodiment of the present invention, the outer ring chamfered portion may be chamfered. When the surface forming this chamfer is orthogonal to the axial direction of the through hole, the through hole can be easily and quickly formed in the outer ring. Thereby, reduction of a processing man-hour can be aimed at.
A plurality of through holes in the outer ring may be formed at appropriate intervals in the circumferential direction. Moreover, the through-hole of an outer ring | wheel may be formed only in one place of the circumferential direction. In this case, the trouble of screwing a plurality of stopper plugs can be saved.

It is sectional drawing of the angular ball bearing which concerns on one Embodiment of this invention. It is an expanded sectional view of the principal part of the angular ball bearing. It is the top view which fractured | ruptured the outer ring | wheel of the angular ball bearing partially. It is sectional drawing of the angular ball bearing of a prior art example.

Explanation of symbols

5 ... Inner ring 6 ... Outer ring 6b ... Raceway surface 6D ... Outer ring outer diameter surface 6h ... Outer ring guide surface 6Hm ... Outer ring end face 6m ... Outer ring grease retaining groove 6r ... Outer ring chamfer 7 ... Ball 8 ... Seal 9 ... Retainer 11 ... Through hole 12 ... Stopper Hd2 ... Cage outer diameter surface Gr ... Grease

Claims (4)

In the angular ball bearing in which a ball held by a cage is interposed between the inner ring and the outer ring, and a bearing space between the inner ring and the outer ring is sealed with a seal,
The retainer is guided on the inner peripheral surface of the outer ring, and an outer ring grease retaining groove that is recessed radially outward is formed on the inner peripheral surface of the outer ring, between the outer diameter surface and the end surface of the outer ring. An angular contact ball bearing characterized in that a through hole communicating from the outer ring chamfered portion to the outer ring grease reservoir groove is formed in the outer ring, and grease is sealed into the outer ring grease reservoir groove from the through hole.   2. The angular contact ball bearing according to claim 1, wherein the outer ring grease retaining groove is formed between the outer ring raceway surface of the inner peripheral surface of the outer ring and the outer ring guide surface guided by the outer diameter surface of the cage.   3. The angular ball bearing according to claim 1, wherein a stopper plug that closes the through hole is provided in the outer ring.   The angular ball bearing according to claim 1, wherein through holes of the outer ring are provided at a plurality of locations in a circumferential direction.

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