JP2007024263A - Lubricating device of rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the agitating resistance of a cooling oil due to the high-speed rotation of a rolling bearing in a lubricating device of the rolling bearing having an inner ring cooling function. <P>SOLUTION: A cooling oil introduction member 11 having a nozzle 12 jetting the cooling oil to a circumferential groove 6 in the end face of an inner ring 2 is disposed on the rear side of an angular ball bearing 1. A seal part 13 facing a tapered surface 2b through a clearance is formed at the extension part 11a of the cooling oil introduction member 11. The axial inner end of the seal part 13 is positioned on the outside of the axial outer end of a retainer 5. Since the cooling oil flows from the inner end of the seal part 13 into the bearing as a lubricating oil, most of the cooling oil spattered to the outer diameter side by a centrifugal force is not captured by the retainer 5 so that the amount of the cooling oil stagnating in the bearing can be reduced. Consequently, the agitating resistance of the cooling oil due to the high-speed rotation of the angular ball bearing 1 can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing lubrication device having an inner ring cooling function.

  In a rolling bearing that supports a rotating shaft that rotates at a high speed, such as a main shaft of a machine tool, the temperature of the inner ring is higher than that of the outer ring due to processing load and the like. For this reason, there is a problem that the bearing preload becomes excessive due to the difference in thermal expansion between the inner ring and the outer ring due to this temperature difference, and the bearing life is shortened.

  For such a problem, the cooling oil supplied from the cooling oil supply device is discharged from one end side in the axial direction of the rolling bearing to the inner ring of the rotating wheel, and the outer diameter surface on one end side of the inner ring from which this cooling oil is discharged. In order to have a cooling function for the inner ring without providing a separate cooling device, a part of the cooling oil is provided as a lubricating oil into the bearing from the gap of the sealing part. There is a lubrication device for a rolling bearing (for example, see Patent Document 1).

  In the one described in Patent Document 1, the outer diameter surface on one end side of the inner ring is used as a tapered surface that expands toward the raceway surface side, and the axially inner end of the seal portion facing this taper surface with a gap is held in the cage. Positioned on the inner side of the outer end of the shaft in the axial direction, a part of the discharged cooling oil is guided along the tapered surface to the raceway surface by centrifugal force accompanying the rotation of the inner ring, and from the inner end of the seal part to the inside of the bearing I try to let it flow. The cooling oil that flows into the bearing from the inner end of the seal portion along the taper surface is guided to the raceway surface of the inner ring as it is along the taper surface, and the outer diameter by centrifugal force from the inner end of the seal portion. Divided into things that scatter to the side.

Japanese Patent Laid-Open No. 2004-360828 (FIGS. 5-7)

  In the rolling bearing lubrication device described in Patent Document 1, the axially inner end of the seal portion opposed to the outer diameter tapered surface of the inner ring with a gap is located inside the axially outer end of the cage. Cooling oil scattered from the inner end of the seal portion to the outer diameter side by centrifugal force is captured by the cage. The ratio of the cooling oil scattered to the outer diameter side by this centrifugal force increases as the rotational speed of the inner ring increases. For this reason, in a rolling bearing that supports a rotating shaft that rotates at a high speed of 10,000 revolutions per minute, such as the main shaft of a machine tool, the amount of cooling oil that is captured by the cage and stays inside the bearing increases. There is a possibility that the agitation resistance of the cooling oil accompanying the high speed rotation of the rolling bearing increases and the power loss increases.

  Accordingly, an object of the present invention is to reduce the agitation resistance of cooling oil accompanying high-speed rotation of a rolling bearing in a rolling bearing lubrication device having an inner ring cooling function.

  In order to solve the above-mentioned problems, the present invention discharges cooling oil supplied from a cooling oil supply device from one end side in the axial direction of a rolling bearing to an inner ring of a rotating wheel, and one end of the inner ring from which this cooling oil is discharged. A bearing in which a seal portion facing the outer diameter surface on the side is provided with a gap, and a part of the cooling oil discharged to one end side of the inner ring is held by a cage through a gap of the seal portion. In the rolling bearing lubrication device that is caused to flow into the inside as lubricating oil, a configuration is adopted in which the axially inner end of the seal portion is positioned outside the axially outer end of the cage.

  In other words, by positioning the axially inner end of the seal portion outside the axially outer end of the cage, most of the cooling oil scattered from the inner end of the seal portion to the outer diameter side by centrifugal force is retained in the cage. The amount of the cooling oil staying in the bearing is reduced so that the stirring resistance of the cooling oil accompanying the high-speed rotation of the rolling bearing can be reduced.

  The outer diameter surface of the inner ring on one end side in the axial direction from which the cooling oil is discharged is a tapered surface that expands toward the raceway surface, so that a part of the discharged cooling oil is centrifuged as the inner ring rotates. It can be efficiently guided to the raceway surface along the tapered surface by force.

  By providing a circumferential groove extending in the circumferential direction on the end face of the inner ring on one end side in the axial direction from which the cooling oil is discharged, the cooling oil is discharged toward the circumferential groove, thereby improving the cooling efficiency of the inner ring. it can.

  In the rolling bearing lubrication device of the present invention, in order to allow a part of the cooling oil to flow into the bearing as lubricating oil, the inner end in the axial direction of the seal portion facing the outer diameter surface on one end side of the inner ring with a gap, By positioning it outside the axial outer end of the cage, most of the cooling oil scattered from the inner end of the seal portion to the outer diameter side by centrifugal force is not captured by the cage. By reducing the amount of the cooling oil that remains, the stirring resistance of the cooling oil accompanying the high-speed rotation of the rolling bearing can be reduced.

  The outer diameter surface of the inner ring on one end side in the axial direction from which the cooling oil is discharged is a tapered surface that expands toward the raceway surface, so that a part of the discharged cooling oil is centrifuged as the inner ring rotates. It can be efficiently guided to the raceway surface along the tapered surface by force.

  By providing a circumferential groove extending in the circumferential direction on the end face of the inner ring on one end side in the axial direction from which the cooling oil is discharged, and cooling oil is discharged toward the circumferential groove, the cooling efficiency of the inner ring can be increased. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a spindle device of a machine tool employing a rolling bearing lubrication device according to the present invention. This spindle device is an angular contact in which a spindle of a tool or a workpiece is attached to an end, and a main shaft 20 that is rotationally driven by a motor (not shown) is two rolling bearings that are incorporated in a bearing box 21 apart in the axial direction. It is supported by a ball bearing 1. Further, as will be described later, a cooling oil supply device 30 that supplies cooling oil for cooling the bearing housing 21 and the inner ring 2 of the angular ball bearing 1 is connected to the spindle device.

  As shown in FIG. 2, the angular ball bearing 1 has a ball 4 held by a cage 5 between the raceway surfaces 2 a and 3 a of the inner ring 2 and the outer ring 3 on the front side where an axial load is applied to the inner ring 2. A counter bore 3b is provided on the inner diameter surface of the outer ring 3, a tapered surface 2b is provided on the outer diameter surface of the inner ring 2 on the back side, and the diameter is increased toward the raceway surface 2a. 6 is provided.

  As shown in FIG. 1, the bearing box 21 has a double structure of an inner box 21a and an outer box 21b, and the inner ring 2 of the two angular ball bearings 1 has a main shaft with an inner ring spacer 22 interposed therebetween. The outer ring 20 is fitted and the both sides are fixed by the inner ring presser 23. Further, the two outer rings 3 with the outer ring spacer 24 interposed therebetween are brought into contact with the end face on the back side of the cooling oil introduction member 11 constituting the lubricating device according to the present invention, and are fitted into the inner box 21a. Both sides are fixed by outer ring pressers 25.

  A cooling oil circulation path 31 is formed between the inner box 21a and the outer box 21b of the bearing box 21, and the cooling oil circulated and supplied from the cooling oil supply device 30 through the supply path 32 and the return path 33 is supplied to the outer box 21b. The cooling oil circulation path 31 is supplied through an introduction hole 34a and a discharge hole 34b provided on the outer diameter surface of the gas.

  Further, the supply passage 32 of the cooling oil supply device 30 is provided with a branch supply passage 32a through which a pressure regulating valve 35 and an oil filter 36 are interposed, and the respective introduction holes 37 provided at both end faces of the inner box 21a. Cooling oil is supplied to the tank. The cooling oil supplied to each introduction hole 37 is introduced into the cooling oil introduction member 11 and, as will be described later, after being used for lubricating the inside of each angular ball bearing 1 and cooling the inner ring 2, The oil is recovered in an oil recovery path 38 provided on the lower side and returned to the cooling oil supply device 30 by an oil pump 39.

  As shown in FIG. 2, the cooling oil introduction member 11 abutted against the rear side end face of the outer ring 3 is fitted in the inner box 21a, and an introduction hole 11b communicating with the introduction hole 37 of the inner box 21a is provided. A nozzle 12 for discharging cooling oil to the circumferential groove 6 of the inner ring 2 is provided at the tip thereof. Further, on the front side of the cooling oil introduction member 11, there is provided an overhanging portion 11a that protrudes toward the inner ring 2 and forms a seal portion 13 that opposes the tapered surface 2b of the inner ring 2 with a gap. An oil storage space 14 a is formed around the circumferential groove 6. Most of the cooling oil discharged to the circumferential groove 6 and cooling the inner ring 2 is accumulated in the oil storage space 14a, and is connected to the rear surface side from the communication hole 11e provided in the cooling oil introduction member 11 by the lid member 15. It moves to the sealed oil storage space 14b.

  A part of the cooling oil discharged to the circumferential groove 6 to cool the inner ring 2 is guided through the gap of the seal portion 13 along the tapered surface 2 b by the centrifugal force accompanying the rotation of the inner ring 2, and the inner side of the seal portion 13. It flows from the end into the bearing as lubricating oil. The cooling oil that has flowed into the bearing from the inner end of the seal portion 13 is directly guided to the raceway surface 2a of the inner ring 2 along the tapered surface 2b, and scattered from the inner end of the seal portion 13 to the outer diameter side by centrifugal force. Divided into what to do.

  The axially inner end of the seal portion 13 formed by the protruding portion 11 a is located outside the axially outer end of the cage 5. Therefore, most of the cooling oil scattered from the inner end of the seal portion 13 to the outer diameter side by centrifugal force is scattered to the outer ring 3 side without being captured by the retainer 5, and the end of the outer ring 3 will be described later. The oil is recovered into the oil recovery passage 38 from the discharge groove 11d provided in the cooling oil introduction member 11 along the portion.

  As shown in FIG. 3, the cooling oil introduction member 11 is provided with a discharge hole 11 c communicating with the oil storage space 14 b and a discharge groove 11 d communicating with the inside of the bearing along the end surface of the outer ring 3. Further, at the lower part of the inner box 21a, there are provided discharge holes 40a, 40b that connect the discharge holes 11c and the discharge grooves 11d to the oil recovery path 38, respectively. Accordingly, the cooling oil that cools the inner ring 2 and accumulates in each oil storage space 14b is recovered in the oil recovery passage 38 through the discharge holes 11c and 40a, and a part of the cooling oil that lubricates the inside of the bearing is discharged into the discharge groove 11d. It is recovered in the oil recovery path 38 through the hole 40b.

  As an example, as shown in FIG. 2, a spindle device equipped with a rolling bearing lubrication device in which the axially inner end of the seal portion 13 is positioned outside the axially outer end of the cage 5, and a comparative example As shown in FIG. 6 of Patent Document 1, a spindle device equipped with a rolling bearing lubrication device in which the axially inner end of the seal portion 31aa is positioned inside the axially outer end of the cage 5 is prepared. did. As shown in FIG. 1, in the spindle device of the example and the comparative example, the main shaft 20 is supported by two angular ball bearings 1, and the diameter of the main shaft 20 (inner diameter of the angular ball bearing 1) is 70 mm. It was. Note that the amount of cooling oil supplied to each lubricating device was 2 liters / minute, the diameter of each nozzle discharging cooling oil was 1.2 mm, and the preload of each bearing was 1 kN.

  For the spindle device equipped with the rolling bearing lubrication device of the above embodiment and the comparative example, the rotational speed N of the motor that rotationally drives the spindle is changed from 5000 rpm to 40000 rpm, and the power consumption W of the motor accompanying the change in the rotational speed N The results of measuring the change in are shown in FIG. As can be seen from this measurement result, the power consumption W of the example is lower than that of the comparative example at any number of revolutions N. In particular, the power consumption W is about 0.4 kW at maximum at a high speed rotation of 25000-35000 rpm. It is low. In this embodiment, the consumption power W is reduced by positioning the inner end in the axial direction of the seal portion, which allows a part of the cooling oil to flow into the bearing as lubricating oil, outside the outer end in the axial direction of the cage. The cooling oil that splashes from the inner end to the outer diameter side is not captured by the cage, the amount of cooling oil that stays inside the bearing is reduced, and the stirring resistance of the cooling oil that accompanies high-speed rotation of the bearing is reduced. It is thought to be due to.

  In the embodiment described above, the rolling bearing is an angular ball bearing. However, the rolling bearing lubrication device according to the present invention can also be applied to other rolling bearings such as a deep groove ball bearing and a roller bearing.

The block diagram which shows the spindle apparatus which employ | adopted the lubricating device of the rolling bearing which concerns on this invention, and the cooling oil supply apparatus connected to this Sectional drawing which expands and shows the A section of the lubricating device of FIG. Sectional drawing which expands and shows the B section of the lubricating device of FIG. The graph which shows the result of having measured the relationship between the motor rotation speed N and the power consumption W

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Angular contact ball bearing 2 Inner ring 3 Outer ring 2a, 3a Raceway surface 2b Tapered surface 3b Counter bore 4 Ball 5 Cage 6 Circumferential groove 11 Cooling oil introduction member 11a Overhang part 11b Inlet hole 11c Discharge hole 11d Discharge groove 11e Communication hole 12 Nozzle 13 Seal part 14a, 14b Oil storage space 15 Lid member 20 Main shaft 21 Bearing box 21a Inner box 21b Outer box 22 Inner ring spacer 23 Inner ring retainer 24 Outer ring spacer 25 Outer ring retainer 30 Cooling oil supply device 31 Cooling oil circulation path 32 Supply path 32a Branch supply path 33 Return path 34a Inlet hole 34b Discharge hole 35 Pressure regulating valve 36 Oil filter 37 Inlet hole 38 Oil recovery path 39 Oil pumps 40a, 40b Discharge hole

Claims (3)

  The cooling oil supplied from the cooling oil supply device is discharged from one end in the axial direction of the rolling bearing to the inner ring of the rotating wheel, and the seal is opposed to the outer diameter surface of one end of the inner ring from which this cooling oil is discharged with a gap. Of a rolling bearing in which a part of cooling oil discharged to one end side of the inner ring is allowed to flow as a lubricating oil into a bearing in which a rolling element is held by a cage through a gap of the seal part. In the lubricating device, the axially inner end of the seal portion is positioned outside the axially outer end of the cage.   The rolling bearing lubrication device according to claim 1, wherein an outer diameter surface of the inner ring on one end side in the axial direction from which the cooling oil is discharged is a tapered surface that expands toward the raceway surface side.   The circumferential groove | channel extended in the circumferential direction was provided in the end surface of the inner ring | wheel of the axial direction one end side where the said cooling oil is discharged, The said cooling oil is discharged toward this circumferential groove. Rolling bearing lubrication equipment.

Images