JP2006329324A - Combined rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain temperature rise in a bearing space on an inner side more than a rolling element of rolling bearings on both ends in two or more lines of combined rolling bearings to which grease lubrication is applied without requiring design change of members other than the bearing. <P>SOLUTION: On upper half sides of respective outer rings 3 of angular ball bearings 1a, 1b and 1c combined in three lines, recessed grooves 7a, 7b and 7c as communication passages communicating with both end surfaces thereof and an outside diameter side thereof are provided, and bearing spaces 6a and 6c in the inner side more than a ball 4 of the angular ball bearings 1a and 1c arranged on both sides and a bearing space 6b of the angular ball bearing 1b arranged in the inner side are communicated with the outside by the recessed grooves 7a, 7b and 7c, and thereby, air heated in the respective bearing spaces 6a, 6b and 6c is delivered to the outside without requiring design change of the members other than the bearing, and temperature rise in the respective bearing spaces 6a, 6b and 6c can be restrained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a combined rolling bearing in which rolling bearings are combined in two or more rows.

  As a bearing that supports a spindle of a machine tool or various rotary machines with high accuracy, a combination rolling bearing in which rolling bearings such as angular ball bearings are arranged in two or more rows may be used. This type of combined rolling bearing is classified into grease-lubricated and oil-mist lubricated. In the case of oil-mist lubricated, the bearing space of each rolling bearing is the The seat part is vented to the outside by a vent hole provided in the housing and shaft, and oil mist is supplied to the bearing space, but in the case of grease lubrication, the bearing space of each rolling bearing is filled with grease, The bearing space inside the rolling elements of the rolling bearings at both ends is blocked from venting to the outside.

  In the combined rolling bearing in which the above-mentioned grease lubrication and the bearing space inside the rolling elements of the rolling bearings at both ends are blocked from ventilation with the outside, the temperature rise in the bearing space where ventilation with the outside is blocked increases. There is a problem that the grease filled in the bearing space tends to deteriorate. Further, in a combination rolling bearing in which rolling bearings are arranged in three or more rows, the temperature rise of the rolling bearings arranged on the inner side becomes large, and the amount of preload due to the difference in thermal expansion between the rolling bearings arranged on both ends is increased. There is a problem that variations occur, which may hinder high-precision shaft support and shorten the bearing life.

  In order to suppress the temperature rise in the bearing space where ventilation from the outside is blocked, vent holes are provided in the housing and shaft at the spacer, as in the case of combined rolling bearings with oil mist lubrication. However, it is essential to place a spacer between the rolling bearings, and it is necessary to change the design of housings and shafts other than the bearings, which limits the design on the user side of the bearings. There is a problem.

  Therefore, an object of the present invention is to provide a temperature in the bearing space inside the rolling elements of the rolling bearings at both ends in two or more rows of combined rolling bearings that are grease-lubricated without requiring a design change of members other than the bearings. It is to suppress the rise.

  In order to solve the above problems, the present invention provides a combined rolling bearing in which a plurality of rolling bearings in which grease is filled in a bearing space in which rolling elements between an inner ring and an outer ring are arranged are combined in two or more rows. A configuration was adopted in which an air passage that vents the bearing space inside the rolling elements of the rolling bearings at both ends combined in two or more rows to the outside is provided in the inner ring or the outer ring raceway.

  That is, by changing the design of the members other than the bearing by providing the inner ring or the outer ring raceway with a ventilation path that ventilates the outside bearing space inside the rolling elements of the rolling bearings at both ends combined in two or more rows. Without the need, the air that has risen in the inner bearing space is exhausted from the air passage to the outside, preventing the temperature rise in these inner bearing spaces and preventing deterioration of the grease filled in the bearing space. I was able to do it.

  By forming the air passage provided in the raceway into a concave groove that is continuous with the end face of the raceway and the radial surface opposite to the bearing space, the air passage can be easily formed at low cost.

  When the outer ring of the plurality of rolling bearings is used as a fixed ring to support a horizontal rotating shaft, the upper half of the outer ring having the recessed groove as the fixed ring is connected to the end surface and the outer diameter surface. Thus, it is possible to prevent the concave groove as the air passage from being blocked by grease or the like.

  In the case where the combined rolling bearing is a combination of the plurality of rolling bearings arranged in three or more rows, the temperature increase of the rolling bearings arranged on the inside is suppressed, and thermal expansion occurs between the rolling bearings arranged at both ends. It is possible to prevent variation in the amount of preload due to the difference between the two.

  The combination rolling bearing may include an angular ball bearing.

  The combination rolling bearing is suitable for supporting a spindle of a machine tool.

  In the combined rolling bearing of the present invention, the inner ring or the outer ring raceway is provided with a ventilation path that ventilates the bearing space inside the rolling elements of the rolling bearings at both ends combined in two or more rows. Without the need to change the design of these parts, the air whose temperature has risen in the inner bearing space is exhausted from the air passage to the outside, and the temperature rise in these inner bearing spaces is suppressed, and the bearing space is filled. It is possible to prevent deterioration of grease.

  By forming the air passage provided in the raceway into a concave groove that is continuous with the end face of the raceway and the radial surface opposite to the bearing space, the air passage can be easily formed at low cost.

  When the outer ring of the plurality of rolling bearings is used as a fixed ring to support a horizontal rotating shaft, the upper half of the outer ring having the recessed groove as the fixed ring is connected to the end surface and the outer diameter surface. Thus, it is possible to prevent the concave groove as the air passage from being blocked by grease or the like.

  In the case where the combined rolling bearing is a combination of the plurality of rolling bearings arranged in three or more rows, the temperature increase of the rolling bearings arranged on the inside is suppressed, and thermal expansion occurs between the rolling bearings arranged at both ends. Therefore, it is possible to prevent a variation in the preload amount due to the difference between the shafts and prevent a decrease in shaft support accuracy and a decrease in bearing life.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment. The combined rolling bearing supports the spindle 11 of the machine tool. As shown in FIG. 1, the angular ball bearings 1a, 1b, and 1c are arranged in three rows, and the angular ball bearings 1a, 1b, and 1c are combined. The bearing space 6 in which the balls 4 are held by the cage 5 between the inner ring 2 and the outer ring 3 is filled with grease (not shown) and is lubricated with grease.

  In the combination rolling bearing, the inner ring 2 of each angular ball bearing 1a, 1b, 1c is fitted to the main shaft 11 of the machine tool, and the outer ring 3 is fixed to the housing 12, and as shown in FIG. On the upper half side of each outer ring 3, concave grooves 7a, 7b, 7c are provided as air passages connected to both end surfaces and the outer diameter surface, and more than the balls 4 of the angular ball bearings 1a, 1c arranged at both ends. The inner bearing spaces 6a and 6c and the bearing space 6b of the angular ball bearings 1b arranged on the inner side are vented to the outside.

  Further, a pin hole 8 for positioning is provided on the end face of the outer ring 3 provided with the concave groove 7a, and each outer ring 3 is connected to the housing 12 so that the concave grooves 7a, 7b, 7c are on the upper half side. It is designed to be positioned. The positioning of the outer ring 3 in the circumferential direction may be performed by other means such as a keyway.

  Therefore, the air whose temperature has risen in each of the bearing spaces 6a, 6b, 6c is discharged to the outside through the concave grooves 7a, 7b, 7c without requiring a design change of members other than the bearings. Temperature rise at 6b and 6c is suppressed. In this embodiment, each of the angular ball bearings 1a, 1b, and 1c is provided with the concave grooves 7a, 7b, and 7c in the same form on the respective outer rings 3, and therefore can have compatibility.

  FIG. 3 shows a second embodiment. This combination rolling bearing has the same basic configuration as that of the first embodiment, and the concave grooves 7a, 7b, 7c are provided only in the outer rings 3 of the angular ball bearings 1a, 1c at both ends. The only difference is that the spaces 6a, 6b, 6c are vented to the outside. In this embodiment, only the angular ball bearings 1a and 1c at both ends can be made compatible.

  FIG. 4 shows a third embodiment. This combination rolling bearing also has the same basic configuration as that of the first embodiment, and is provided with concave grooves 7a and 7b on both end faces of the outer ring 3 of the inner angular ball bearing 1b, and angular ball bearings on both ends. A difference is that a concave groove 7c connected to the concave grooves 7a, 7b is provided on the outer diameter surface of the outer ring 3 of 1a, 1c, and the bearing spaces 6a, 6b, 6c are vented to the outside. Even in this embodiment, only the angular ball bearings 1a and 1c at both ends can be made compatible.

  In each embodiment described above, the same angular ball bearings are combined in three rows. However, the combined rolling bearing is not limited to the angular ball bearing, and other ball bearings, roller bearings, tapered roller bearings, double row Rolling bearings and the like can be combined with the same or different ones, and each rolling bearing may have a seal. The rolling bearings may be combined in two rows or four or more rows, and a spacer may be arranged between the rolling bearings as necessary.

  Further, in each of the above-described embodiments, the inner bearing space of the rolling bearings at both ends and the bearing space of the inner rolling bearing are vented from the both sides of the combined rolling bearing to the outside by a concave groove provided as an air passage in the outer ring. However, the air may be vented to the outside only on one side, and the air passage can be provided on the inner ring side.

The longitudinal cross-sectional view which shows the combination rolling bearing of 1st Embodiment FIG. 1 is a partially omitted perspective view showing an outer ring of the angular ball bearing of FIG. Longitudinal sectional view showing a combination rolling bearing of the second embodiment Longitudinal sectional view showing a combination rolling bearing of a third embodiment

Explanation of symbols

1a, 1b, 1c Angular contact ball bearing 2 Inner ring 3 Outer ring 4 Ball 5 Cage 6a, 6b, 6c Bearing space 7a, 7b, 7c Groove 8 Pin hole 11 Spindle 12 Housing

Claims (7)

  In a combined rolling bearing in which a plurality of rolling bearings in which grease is filled in a bearing space in which rolling elements between the inner ring and the outer ring are arranged are combined in two or more rows, the rolling bearings at both ends combined in two or more rows are combined. A combined rolling bearing, characterized in that an air passage that vents the bearing space inside the rolling element to the outside is provided in the inner ring or outer ring raceway.   The combined rolling bearing according to claim 1, wherein the air passage provided in the bearing ring is a concave groove continuous with an end face of the bearing ring and a radial surface opposite to the bearing space.   An outer ring of the plurality of rolling bearings is used as a fixed ring to support a horizontal rotating shaft, and the upper half side of the outer ring using the concave groove as the fixed ring is connected to an end surface and an outer diameter surface. Item 3. A combined rolling bearing according to Item 2.   4. The combination rolling bearing according to claim 3, further comprising means for positioning so that the concave groove comes to an upper half side of the outer ring.   The combined rolling bearing according to any one of claims 1 to 4, wherein the combined rolling bearing is a combination of the plurality of rolling bearings arranged in three or more rows.   The combined rolling bearing according to claim 1, wherein the combined rolling bearing includes an angular ball bearing.   The combined rolling bearing according to claim 1, wherein the combined rolling bearing supports a spindle of a machine tool.

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