JP2014062618A - Lubricating structure of bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating structure of a bearing device capable of excellently lubricating rolling bearings, and efficiently cooling inner rings and an inner ring spacer of the rolling bearings, and a main shaft fitted to their inner peripheries.SOLUTION: In a bearing device, an outer ring spacer 4 and an inner ring spacer are respectively disposed between outer rings and between inner rings 3 of a plurality of rolling bearings arranged in the axial direction, the outer rings and the outer ring spacer 4 are disposed in a housing, and the inner rings 3 and the inner ring spacer are fitted to a main shaft. A nozzle 12 is disposed on the outer ring spacer 4 for spraying a mixture of air and oil, or a lubrication fluid composed of only the oil, to outer peripheral faces of the inner rings 3 or the inner ring spacer to supply the same to the rolling bearings. The nozzle 12 is inclined forward in the rotating direction of the main shaft at their discharge port side.

Description

  The present invention relates to a lubrication structure for a bearing device, for example, a main shaft of a machine tool and a lubrication structure for a bearing device incorporated in the main shaft.

  In the spindle device of a machine tool, due to the necessity of ensuring machining accuracy and improving machining efficiency, the bearings used for supporting the spindle are required to have conflicting technologies of low temperature rise and high speed. For this reason, various new technologies have recently been introduced, such as bearing cooling methods and lubrication methods.

  Regarding the cooling method of the bearing, for example, in Patent Document 1, cold air is blown into the gap between the bearings, and the shaft is ejected in an angle range of −45 ° to + 45 ° with respect to the rotation surface on the shaft side with respect to the rotation direction of the shaft. A technique for cooling and indirectly suppressing the temperature rise of the inner ring of the bearing is disclosed. When the inner ring is cooled, there are an action of releasing generated heat by the cold air and an action of reducing the bearing preload by lowering the inner ring temperature, and a synergistic effect of suppressing the bearing temperature can be expected by these actions.

  As for a bearing lubrication method, for example, Patent Document 2 discloses a technique of an air-oil lubrication method suitable for high-speed operation. In this technique, an inclined surface portion that follows the raceway surface is provided on the outer diameter surface of the bearing inner ring, and a ring-shaped nozzle member is provided along the inclined surface portion with a gap. The nozzle member is provided with a nozzle that discharges air oil to the inclined surface of the inner ring, and the oil in the air oil discharged from the nozzle can be reliably attached to the inclined surface. The adhering oil becomes an adhering flow by rotation and centrifugal force and adhering force, and the oil is surely introduced into the bearing. As a result, the speed of the bearing can be increased and the noise can be reduced as compared with the conventional oil supply method.

  When the technique of the air-oil lubrication method is applied to a bearing device in which a plurality of rolling bearings are arranged in the axial direction, for example, as shown in FIGS. That is, as shown in FIG. 19, this bearing device includes two rolling bearings 1, 1 aligned in the axial direction, and between the outer rings 2, 2 and between the inner rings 3, 3 of each rolling bearing 1, 1. A seat 4 and an inner ring spacer 5 are interposed. In this example, the rolling bearing 1 is an angular ball bearing. The two rolling bearings 1 are used with an initial preload set according to the width dimension difference between the outer ring spacer 4 and the inner ring spacer 5.

  As shown in FIG. 20, the outer ring spacer 4 is composed of an outer ring spacer body 10 and a pair of nozzle members 11, 11. Each nozzle member 11 is provided with a nozzle 12 that supplies air oil to the rolling bearing 1. ing. The discharge port 12a of the nozzle 12 faces the shoulder surface (slope portion) 3b of the inner ring 3 with a clearance δ. On the shoulder surface 3 b of the inner ring 3, a plurality of annular recesses 20 are formed in the circumferential direction at axial positions facing the discharge ports 12 a of the nozzles 12.

  Air oil for lubrication of the bearing is discharged from the nozzle 12 from the external air oil supply device 45 through the supply port 40, the supply hole 47, and the introduction path 13 in the outer ring spacer 4. The oil in the discharged air oil is sprayed to the inner ring 3 through the annular recess 20 of the inner ring 3 and adheres to the inner ring 3. The adhering oil is guided to the raceway surface 3 a side by the adhering force and the centrifugal force generated by the rotation of the inner ring 3, and is guided to the raceway surface 3 a side to be used for lubrication of the rolling bearing 1.

JP 2000-161375 A Japanese Patent No. 4261083

  In order to increase the speed of the bearing, a reliable supply of lubricating oil is essential as well as the suppression of the bearing temperature during operation. Since the bearing temperature suppression technology of Patent Document 1 is cooling of a bearing using compressed air, it is possible to construct a device at a relatively low cost, but there is a problem that a large amount of air is consumed. Moreover, although the lubrication method of patent document 2 can obtain a favorable result regarding lubrication, it is required to further enhance the cooling effect in order to meet the demand for higher speed.

  An object of the present invention is to provide a lubrication structure for a bearing device that can satisfactorily lubricate a rolling bearing and that can efficiently cool the inner ring of the rolling bearing, the inner ring spacer, and the main shaft fitted to the inner periphery thereof. That is.

  The lubricating structure of the bearing device according to the present invention includes an outer ring spacer and an inner ring spacer interposed between outer rings and inner rings of a plurality of rolling bearings arranged in the axial direction, and the outer ring and the outer ring spacer are installed in a housing. In the bearing device in which the inner ring and the inner ring spacer are fitted to the main shaft, the outer ring spacer is sprayed with a lubricating fluid consisting of air and oil or a mixture of oil only on the outer ring of the inner ring or the inner ring spacer. The nozzle to be supplied to the rolling bearing is characterized in that the discharge port side of the nozzle is inclined forward in the rotational direction of the main shaft.

According to this configuration, the lubricating fluid is sprayed to the outer ring of the inner ring or the inner ring spacer from the nozzle provided in the outer ring spacer, and the lubricating fluid is supplied to the rolling bearing. Oil in the lubricating fluid is stably applied to the rolling bearing, and the rolling bearing can be lubricated well.
Simultaneously with the lubrication, the inner ring or the inner ring spacer is cooled by spraying a lubricating fluid onto the outer peripheral surface of the inner ring or the inner ring spacer. Since the nozzle has the discharge port side inclined forward in the direction of rotation of the main shaft, the lubricating fluid becomes a swirl flow along the outer peripheral surface of the inner ring or the inner ring spacer and flows stably in the direction of rotation of the main shaft. Thereby, it can be expected that the surface of the inner ring or inner ring spacer is deprived of heat and effectively cooled. By cooling the inner ring or the inner ring spacer, the main shaft fitted to the inner periphery is cooled.

In the lubricating structure of the bearing device according to the present invention, the discharge port of the nozzle may be opposed to the raceway surface on the outer peripheral surface of the inner ring with a clearance on the shoulder surface continuing to the inner ring spacer side. The shoulder surface may be an inclined surface whose outer diameter increases as the distance from the raceway surface increases.
When the discharge port of the nozzle is opposed to the shoulder surface of the inner ring with a gap, the lubricating fluid discharged from the discharge port of the nozzle is sprayed onto the shoulder surface of the inner ring. The oil of the lubricating fluid sprayed on the shoulder surface is guided to the raceway surface along the shoulder surface, so that the raceway surface of the inner ring can be lubricated well. When the shoulder surface is an inclined surface, the centrifugal force accompanying the rotation of the inner ring acts on the oil adhering to the shoulder surface, and the oil is smoothly guided toward the raceway surface of the inner ring on the outer diameter side.
Moreover, the effect of cooling the inner ring is high by spraying the lubricating fluid directly onto the shoulder surface of the inner ring.

In the lubricating structure of the bearing device according to the present invention, the nozzle is provided so as to discharge the lubricating fluid toward the outer peripheral surface of the inner ring spacer, and the outer peripheral surface of the inner ring spacer is discharged from the nozzle. Alternatively, the lubricating fluid may be guided to the rolling bearings on both sides.
In this case, the lubricating fluid discharged from the discharge port of the nozzle is sprayed on the outer peripheral surface of the inner ring spacer. The lubricating fluid sprayed on the outer peripheral surface of the inner ring spacer is well guided to the rolling bearings on both sides along the outer peripheral surface of the inner ring spacer, and is used for lubrication of the rolling bearing. Moreover, the effect of cooling the inner ring spacer is high by spraying the lubricating fluid directly on the outer peripheral surface of the inner ring spacer.

The outer circumferential surface of the inner ring spacer is an inclined surface where the outer diameter of the portion to which the lubricating fluid discharged from the nozzle is sprayed is the smallest, and the outer diameter becomes larger toward the rolling bearing from the portion, and the inner ring The outer diameter of the outer end in the axial direction on the outer peripheral surface of the spacer may be the same or larger than the outer diameter of the inner ring spacer side end of the inner ring of the rolling bearing.
If the outer peripheral surface of the inner ring spacer is an inclined surface having the above shape, the oil adhering to the outer peripheral surface of the inner ring spacer out of the lubricating fluid discharged from the nozzles is caused by the centrifugal force accompanying the rotation of the inner ring spacer between the inner rings. It can be smoothly guided to the rolling bearing side along the outer peripheral surface of the seat.

In addition, a circumferential groove located at a location where the lubricating fluid discharged from the nozzle is sprayed on the outer peripheral surface of the inner ring spacer, and one end connected to the circumferential groove and a circumferential phase in the rotational direction of the main shaft You may provide the spiral groove which approaches the said rolling bearing so that it shifts | deviates.
In this case, oil in the lubricating fluid discharged from the nozzle accumulates in the circumferential groove of the inner ring spacer, and the oil is smoothly fed to the rolling bearing side along the spiral groove as the inner ring spacer rotates. It is done.

  The lubricating fluid may be air oil that transports liquid oil by air, or may be oil mist that transports mist-like oil by air.

  The lubrication structure for a bearing device according to the present invention can be suitably used for supporting a main shaft of a machine tool. In that case, the rolling bearing can be lubricated well, and the inner ring of the rolling bearing, the inner ring spacer, and the main shaft fitted to the inner periphery of the rolling bearing can be efficiently cooled, enabling operation in a high speed region. Become.

  The lubricating structure of the bearing device according to the present invention includes an outer ring spacer and an inner ring spacer interposed between outer rings and inner rings of a plurality of rolling bearings arranged in the axial direction, and the outer ring and the outer ring spacer are installed in a housing. In the bearing device in which the inner ring and the inner ring spacer are fitted to the main shaft, the outer ring spacer is sprayed with a lubricating fluid consisting of air and oil or a mixture of oil only on the outer ring of the inner ring or the inner ring spacer. The nozzle to be supplied to the rolling bearing is provided with the discharge port side of the nozzle inclined forward in the rotational direction of the main shaft, so that the rolling bearing can be lubricated well and between the inner ring and the inner ring of the rolling bearing. The seats and the main shafts fitted to the inner peripheries can be efficiently cooled.

1 is a cross-sectional view of a spindle device in which a bearing device having a lubrication structure according to a first embodiment of the present invention is incorporated. It is the figure which extracted and expanded a part of FIG. It is the figure which extracted and represented a part of III-III cross section of FIG. FIG. 4 is a partially enlarged view of FIG. 3. FIG. 3 is a diagram showing a modification of the part shown in FIG. 2. It is a figure which shows the other modification of the part represented by FIG. It is sectional drawing of the oil discharge part of the modification shown in FIG. It is sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the lubrication structure which concerns on 2nd Embodiment of this invention. It is sectional drawing of the bearing apparatus. It is XX sectional drawing of FIG. It is the elements on larger scale of FIG. It is sectional drawing of the modification of the bearing apparatus shown in FIG. It is the elements on larger scale of FIG. It is sectional drawing of the other modification of the bearing apparatus shown in FIG. It is the elements on larger scale of FIG. FIG. 10 is a cross-sectional view of still another modification of the bearing device shown in FIG. 9. It is the elements on larger scale of FIG. FIG. 10 is a cross-sectional view corresponding to the XX cross section in FIG. 9 of the bearing device as a reference example. It is sectional drawing of the bearing apparatus provided with the lubrication structure which is a proposal example. It is the figure which extracted and expanded a part of FIG.

A lubricating structure of a bearing device according to a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, this bearing device includes two rolling bearings 1, 1 aligned in the axial direction, and an outer ring spacer 4 between outer rings 2, 2 and between inner rings 3, 3 of each rolling bearing 1, 1. And the inner ring spacer 5 is interposed. The rolling bearing 1 is an angular ball bearing, and a plurality of rolling elements 8 are interposed between the raceway surfaces 3 a and 2 a of the inner and outer rings 3 and 2. The rolling elements 8 are held by the cage 9 at an equal circumference. The two rolling bearings 1 and 1 are arranged in combination with each other on the back surface, and are used by setting the initial preload of each rolling bearing 1 and 1 depending on the width dimension difference between the outer ring spacer 4 and the inner ring spacer 5.

  FIG. 1 shows a state in which the bearing device is used to support the spindle of a machine tool. The outer rings 2 and 2 and the outer ring spacer 4 of the rolling bearings 1 and 1 are fitted to the inner peripheral surface of the housing 6, and the inner rings 3 and 3 and the inner ring spacer 5 of the rolling bearings 1 and 1 are fitted to the outer peripheral surface of the main shaft 7. Match. The outer rings 2, 2 and the outer ring spacer 4 are, for example, a clearance fit with respect to the housing 6, and are positioned in the axial direction by the step portion 6 a of the housing 6 and the end cover 40. The inner rings 3 and 3 and the inner ring spacer 5 are, for example, an interference fit with respect to the main shaft 7 and are positioned in the axial direction by the positioning spacers 41 and 42 on both sides. Note that the positioning spacer 42 on the left side of the figure is fixed by a nut 43 screwed onto the main shaft 7.

  As shown in FIG. 2, the outer ring spacer 4 includes a pair of outer ring spacer main bodies 10 having a substantially T-shaped cross section and a pair of portions disposed on both sides of a portion corresponding to a vertical portion of the T shape in the outer ring spacer main body 10. It is composed of link-like nozzle members 11 and 11. Each nozzle member 11 has a nozzle 12 that supplies air oil, which is a lubricating fluid, to the rolling bearing 1. The nozzle 12 is provided in a protruding portion 11 a that protrudes into the bearing in the nozzle member 11. The discharge port 12a of the nozzle 12 is open to the inner peripheral surface of the protruding portion 11a, and this inner peripheral surface is opposed to the shoulder surface 3b, which is an inclined surface following the raceway surface 3a of the inner ring 3, with a clearance δa. ing. The size of the clearance δa is, for example, ½ or less of the diameter of the nozzle 12. This is to prevent the pressure of the air oil discharged from the nozzle 12 from dropping suddenly when considering the problem of noise.

The inclination angle α of the shoulder surface 3b of the inner ring 3 is an angle at which air oil sprayed onto the shoulder surface 3b can be introduced into the raceway surface 3a as an adhering flow on the shoulder surface 3b. Specifically, it is proportional to the dmn value (dm: pitch circle diameter mm of the rolling element 8, n: maximum rotational speed min ⁻¹ ), which is an index of the rotational speed of the main shaft 7, and the following formula 1 (“in air-oil lubrication” Approximate values can be obtained by “miniaturization of the amount of oil supplied” (quoted from NTN technical review No. 72 (2004) 15).
α ° = 0.06 × dmn value / 10000 Equation 1

  As shown in FIG. 3, a plurality of nozzles 12 (three in this example) are provided at equal intervals in the circumferential direction. Each nozzle 12 is linear, and the discharge port 12a side is inclined forward in the rotational direction L1 of the main shaft 7. That is, each nozzle 12 is at a position offset from an arbitrary radial straight line L2 in a cross section perpendicular to the axis of the outer ring spacer 4 in a direction perpendicular to the straight line L2. The offset amount OS is, for example, in the range of 0.4D to 0.5D with respect to the outer diameter D of the inner ring 3 at the nozzle 12 position. Only one nozzle 12 may be provided in the circumferential direction.

  In FIG. 2, the outer ring spacer main body 10 and the nozzle member 11 are provided with an introduction path 13 for introducing air oil into the nozzle 12. The introduction path 13 includes an external introduction port 14 formed of an annular groove formed on the outer peripheral surface of the outer ring spacer body 10, and a plurality (the same number as the nozzles 12) radial holes 15 extending from the external introduction port 14 toward the inner diameter side. And the axial hole 16 extending in the axial direction from the bottom of the radial hole 15, and the tip of the axial hole 16 communicates with the end opposite to the discharge port 12 a of the nozzle 12. The axial hole 16 has a portion 16a formed in the outer ring spacer body 10 and a portion 16b formed in the nozzle member 11, and is provided on the side surface of the nozzle member 11 serving as a connecting portion between both the portions 16a and 16b. Countersink hole 16c having a diameter larger than that of both portions 16a and 16b is provided. When only one nozzle 12 is provided in the circumferential direction, the external introduction port 14 may be a countersink hole.

  As shown in FIG. 1, a notch 16 serving as an air oil exhaust port is provided at a portion of the outer ring spacer body 10 that protrudes in the axial direction from the outer diameter end of the nozzle member 11. By arranging the outer ring 2 of the rolling bearing 1 adjacent to the outer ring spacer 4, the notch 16 has an opening shape that communicates the bearing space of the rolling bearing 1 and the outside of the bearing device.

  An air oil supply device 45 is provided outside the spindle device, and the air oil delivered from the air oil supply device 45 passes through the supply port 46 of the end surface cover 40 and the supply hole 47 in the housing 6, so that the outer ring spacer 4 It is supplied to the external introduction port 14. The housing 6 is provided with an exhaust hole 48. The exhaust hole 48 communicates with the notch 16 of the outer ring spacer body 10 through the connection hole 49.

  In the bearing device having this configuration, the air oil supplied from the air oil supply device 45 is discharged from the nozzle 12 through the introduction path 13 of the outer ring spacer 4. By setting the size of the clearance δa to be ½ or less of the diameter of the nozzle 12, the pressure of the air oil discharged from the nozzle 12 does not drop rapidly, and the generation of noise can be suppressed. The discharged air oil is sprayed onto the shoulder surface 3b of the inner ring 3, and the oil of the air oil adheres to the shoulder surface 3b. This oil is smoothly guided along the inclined surface of the shoulder surface 3b to the large-diameter track surface 3a side by the centrifugal force accompanying the rotation of the inner ring 3. By setting the inclination angle α of the shoulder surface 3b to the angle represented by the formula 1, a good oil adhesion flow can be obtained. Thus, since the oil of air oil is stably supplied to the rolling bearing 1, the rolling bearing 1 can always be lubricated satisfactorily.

  Simultaneously with lubrication, air oil is blown onto the inner ring 3 to cool the inner ring 3. Since the nozzle 12 has the discharge port 12a side inclined forward in the rotation direction of the main shaft 7, the air oil flows in a rotational flow along the outer peripheral surface of the inner ring 3 and flows stably in the rotation direction of the main shaft 7. Thereby, it can be expected that the surface of the inner ring 3 is deprived of heat and effectively cooled. It has been confirmed by tests that the cooling effect is the best when the offset amount OS of the nozzle 12 is 0.4 to 0.5 times the outer diameter D of the inner ring 3. By cooling the inner ring 3, the main shaft 7 fitted to the inner periphery of the inner ring 3 is also cooled.

  As shown in FIG. 5, an annular recess 20 may be provided at an axial position on the shoulder surface 3 b of the inner ring 3 where air oil is sprayed. When the annular recess 20 is provided, the discharge speed of the air oil discharged from the nozzle 12 increases, and the oil adherent flow along the shoulder surface 3b is favorably performed.

  As shown in FIG. 6, a ridge 21 having an inner diameter smaller than the other may be provided at the axial end of the inner peripheral surface of the nozzle member 11. The clearance δb between the ridge 21 and the shoulder surface 3b of the inner ring 3 is (size of the clearance δb) × (circumferential length of the clearance δb at the nozzle 12 position) about 10 times the total hole diameter area of the nozzle 12. To be. The total hole diameter area of the nozzles 12 is an area obtained by multiplying the hole diameter area of one nozzle 12 by the number of nozzles 12. By determining the clearance δb in this way, the ridges 21 function as a sound insulation wall that prevents the injection sound of the air oil discharged from the nozzle 12 from leaking to the rolling bearing 1 side, and noise can be reduced.

  The lubricating fluid may be an oil mist that conveys mist-like oil by air. Further, the lubricating fluid may be oil lubrication composed only of oil. Oil lubrication can be expected to have a cooling effect on the inner ring 3 more than air oil lubrication and oil mist lubrication. Also in the case of oil lubrication, it can be set as the same structure as 1st Embodiment or its modification (FIG. 5, FIG. 6).

  In oil lubrication, since no air injection sound is generated, the ridges 21 as the sound insulation walls in the configuration of FIG. 6 are unnecessary. However, it is effective to provide the same ridges 21 as in FIG. 6 and to function the ridges 21 in order to suppress the amount of oil flowing into the rolling bearing 1. The amount of lubricating oil can be controlled by adjusting the dimension of the clearance δb, and a small amount of oil lubrication using the flow of adhesion on the shoulder surface 3b of the inner ring 3 can be performed while the inner ring 3 is cooled. The angle α of the shoulder surface 3b of the inner ring 3 in oil lubrication can be obtained in the same manner by the above-described formula 1 used in air-oil lubrication. In addition, the angle of the nozzle 12 with respect to the rotation direction L1 is slightly 0 ° or slightly opposite to the raceway surface 3a of the inner ring 3 so that the amount of oil flowing into the rolling bearing 1 does not become excessive. You may tilt.

  When the ridge 21 is provided on the nozzle member 11 by oil lubrication, the amount of oil discharged from the gap δb between the ridge 21 and the shoulder surface 3b of the inner ring 3 is limited among the oil discharged from the nozzle 12. The remaining oil discharge needs to be considered. FIG. 7 shows an example of an oil discharge unit devised for oil discharge. In this example, the inner peripheral surface of the outer ring spacer main body 10 is retracted to the outer diameter side from the inner peripheral surface of the nozzle member 11, and the oil reservoir 22 is provided between the outer ring spacer main body 10 and the inner ring spacer 5. In addition, oil drain grooves 23 and 24 that communicate with the axially outer side of the oil reservoir 22 and the nozzle member 11 are provided on the inner surface and the outer peripheral surface of the nozzle member 11 that are in contact with the outer ring spacer body 10. By sucking with an oil discharge pump (not shown) or the like, the oil in the oil reservoir 22 is discharged to the outside of the bearing device through the oil discharge grooves 23 and 24 and the notch 16.

  8 to 12 show a lubricating structure of a bearing device according to the second embodiment of the present invention. As shown in FIG. 8, this bearing device is also composed of two rolling bearings 1 and 1 arranged in the axial direction, an outer ring spacer 4 and an inner ring spacer 5 as in the first embodiment. It is used for supporting the main shaft 7. Parts having the same configuration as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 9, the second embodiment is different from the first embodiment in that the outer ring spacer 4 is composed of a single member, and the rolling bearing 1 is disposed at the axial center of the outer ring spacer 4. Nozzle 12 for supplying air oil to is provided. The discharge port 12 a of the nozzle 12 opens on the inner peripheral surface of the outer ring spacer 4. The inner peripheral surface of the outer ring spacer 4 faces the outer peripheral surface of the inner ring spacer 5 with a gap δc.

  As shown in FIG. 10 and FIG. 11 which is a partially enlarged view thereof, a plurality (three in this example) of nozzles 12 are provided in the circumferential direction. Each nozzle 12 is linear, and the discharge port 12a side is inclined forward in the rotational direction L1 of the main shaft 7. That is, each nozzle 12 is at a position offset (offset amount OS) from an arbitrary radial straight line L2 in a cross section perpendicular to the axis of the outer ring spacer 4 in a direction perpendicular to the straight line L2. Only one nozzle 12 may be provided in the circumferential direction.

In FIG. 9, the outer ring spacer 4 is provided with an introduction path 13 for introducing air oil into the nozzle 12. The introduction path 13 includes an external introduction port 14 formed of an annular groove formed on the outer peripheral surface of the outer ring spacer 4 and the same number of communication holes 30 as the nozzles 12 communicating the external introduction port 14 and each nozzle 12. Become. When only one nozzle 12 is provided in the circumferential direction, the external introduction port 14 may be a countersink hole.
The outer ring spacer 4 of the second embodiment is not provided with the air oil exhaust notch 16 (FIG. 1) provided in the outer ring spacer 4 of the first embodiment.

  In the bearing device having this configuration, the air oil supplied from the air oil supply device 45 is discharged from the nozzle 12 through the introduction path 13 of the outer ring spacer 4. As shown by the arrows in FIG. 9, the discharged air oil is blown against the outer peripheral surface of the inner ring spacer 5, passes through the clearance δc between the outer ring spacer 4 and the inner ring spacer 5, and the rolling bearings 1 on both sides. , Further passes through the rolling bearing 1 and is discharged out of the bearing. When the air oil passes through the rolling bearing 1, the oil in the air oil adheres to each part of the rolling bearing 1 and is used for lubrication.

  Simultaneously with the lubrication, air oil is sprayed onto the inner ring spacer 5 to cool the inner ring spacer 5. Since the nozzle 12 has the discharge port 12a side inclined forward in the rotation direction of the main shaft 7, the air oil flows as a swirl flow along the outer peripheral surface of the inner ring spacer 5 and stably flows in the rotation direction of the main shaft 7. Thereby, it can be expected that the surface of the inner ring spacer 5 is deprived of heat and effectively cooled. By cooling the inner ring spacer 5, the inner ring 3 and the main shaft 7 in contact with the inner ring spacer 5 are also cooled.

  12 and 13 show a modification of the second embodiment. This bearing device has a cross-sectional shape in which the outer diameter of the outer peripheral surface of the inner ring spacer 5 is the smallest at the location A where the air oil discharged from the nozzle 12 is sprayed, and the outer diameter increases from the location A toward the rolling bearing 1. Is a V-shaped inclined surface, and the outer diameter of the axial outer ends B, B on the outer peripheral surface of the inner ring spacer 5 is the same as the outer diameter of the inner ring spacer side end C of the inner ring 3 of the rolling bearing 1; Or enlarged. As a result, as shown in FIG. 13, the oil 25 adhered to the outer peripheral surface of the inner ring spacer 5 out of the air oil discharged from the nozzle 12 is removed from the inner ring spacer 5 by the centrifugal force accompanying the rotation of the inner ring spacer 5. It can be smoothly guided to the rolling bearing 1 side along the outer peripheral surface.

  Further, as shown in FIGS. 14 and 15, the inner peripheral surface of the outer ring spacer 4 may be formed in a cross-sectional mountain shape parallel to the outer peripheral surface of the inner ring spacer 5. In this case, the clearance between the outer ring spacer 4 and the inner ring spacer 5 becomes narrow over the entire area in the axial direction. By doing so, air of the air oil flows toward the rolling bearing 1 with a high flow rate. The oil that is guided by the air flow and adheres to the outer peripheral surface of the inner ring spacer 5 flows smoothly toward the rolling bearing 1.

  16 and 17 show different modifications. In this bearing device, a circumferential groove 26 located at a location where air oil discharged from the nozzle 12 is sprayed on the outer peripheral surface of the inner ring spacer 5 and one end connected to the circumferential groove 26 and circular in the rotational direction L1 of the main shaft 7. Spiral grooves 27 and 27 approaching the rolling bearing 1 as the circumferential phase is shifted are provided. In this case, the oil 25 of the air oil discharged from the nozzle 12 accumulates in the circumferential groove 26 of the inner ring spacer 5, and the oil 25 rolls along the spiral groove 27 as the inner ring spacer 26 rotates. Smoothly sent to 1 side. That is, the oil 25 is sent using the effect of the screw pump.

  Although not included in the scope of the present invention, lubricating fluid such as air oil is sprayed from the nozzle 12 provided on the outer ring spacer 4 to the outer peripheral surface of the inner ring spacer 5 to lubricate the rolling bearing 1 and cool the bearing device and the main shaft 7. 18, even if the discharge port 12a of the nozzle 12 is not inclined forward in the rotation direction L1 of the main shaft 7 as shown in FIG. 18, although the cooling effect is inferior to that of the inclined one, the cooling effect is moderate. Can get.

  Since the cooling structure of the bearing device of the present invention has a high cooling effect on the bearing device and the main shaft 7 as described in each embodiment, the main shaft device can be operated in a high-speed region. For this reason, this bearing apparatus can be used suitably for support of the spindle of a machine tool.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Outer ring 2a ... Raceway surface 3 ... Inner ring 3a ... Raceway surface 3b ... Shoulder surface 4 ... Outer ring spacer 5 ... Inner ring spacer 6 ... Housing 7 ... Main shaft 12 ... Nozzle 12a ... Discharge port 25 ... Oil 26 ... Circumferential groove 27 ... spiral groove L1 ... rotational direction δa ... clearance

Claims (8)

An outer ring spacer and an inner ring spacer are interposed between outer rings and inner rings of a plurality of rolling bearings arranged in the axial direction, respectively. The outer ring and outer ring spacer are installed in a housing, and the inner ring and inner ring spacer are fitted to the main shaft. Bearing device,
A nozzle that blows a lubricating fluid consisting of air and oil or a mixture of only oil onto the outer ring spacer and an outer peripheral surface of the inner ring or the inner ring spacer and supplies it to the rolling bearing is provided on the discharge port side of the nozzle. And a lubricating structure for a bearing device, wherein the main shaft is tilted forward in the rotational direction.   2. The bearing structure according to claim 1, wherein the discharge port of the nozzle is opposed to a raceway surface on an outer peripheral surface of the inner ring with a clearance on a shoulder surface continuing to the inner ring spacer side. 3. Lubrication structure of the device.   3. The lubrication structure for a bearing device according to claim 2, wherein the shoulder surface is an inclined surface whose outer diameter increases as the distance from the raceway surface increases.   2. The lubricating structure for a bearing device according to claim 1, wherein the nozzle is provided so as to discharge the lubricating fluid toward an outer peripheral surface of the inner ring spacer, and the outer peripheral surface of the inner ring spacer is disposed on the nozzle. A lubrication structure of a bearing device having a shape that guides the lubricating fluid discharged from the cylinder to the rolling bearings on both sides.   5. The lubricating structure of the bearing device according to claim 4, wherein the outer peripheral surface of the inner ring spacer has the smallest outer diameter of a portion to which the lubricating fluid discharged from the nozzle is sprayed, and the portion is moved from the portion to the rolling bearing. The outer diameter of the inner ring spacer is the same as the outer diameter of the inner ring spacer side end of the inner ring of the rolling bearing. Large bearing device lubrication structure.   5. The lubricating structure of the bearing device according to claim 4, wherein a circumferential groove located at a position where the lubricating fluid discharged from the nozzle is sprayed on an outer circumferential surface of the inner ring spacer, and one end of the circumferential groove A cooling structure for a bearing device provided with a spiral groove that approaches the rolling bearing as the circumferential phase shifts in the rotation direction of the main shaft.   7. The lubricating structure for a bearing device according to claim 1, wherein the lubricating fluid is air oil that conveys liquid oil by air, or oil mist that conveys mist-like oil by air. The lubricating structure of the bearing device.   The lubricating structure for a bearing device according to any one of claims 1 to 7, which is used for supporting a main shaft of a machine tool.

Images