WO2018181033A1 - Cooling structure for bearing device - Google Patents

Abstract

An outer ring spacer (4) and an inner ring spacer (5) are interposed between a plurality of rolling bearings (1) arranged in the axial direction in a bearing device (J). A supply port (10) for supplying cooling compressed air A toward the outer circumferential surface of the inner ring spacer (5) is provided in the inner circumferential surface of the outer ring spacer (4). An exhaust port (20) for the compressed air (A) is provided in the axial end surface of the outer ring spacer (4). Barrier walls (15) for preventing the compressed air supplied through the supply port (10) from flowing into a bearing space (30) are provided at both axial ends of the inner ring spacer (5) so as to protrude toward the radially outer side. A part of the barrier walls (15) faces the inner ring spacer (5) through a minute gap (16) to form a first labyrinth seal (LS).

Description

Cooling structure of bearing device Related applications

This application claims the priority of Japanese Patent Application No. 2017-066513 filed on Mar. 29, 2017, Japanese Patent Application No. 2017-197619 filed on Oct. 11, 2017, and Japanese Patent Application No. 2017-197620 filed on Oct. 11, 2017. The entirety of which is hereby incorporated by reference as part of the present application.

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

In the spindle device of machine tools, it is necessary to suppress the temperature rise of the device in order to ensure machining accuracy. However, recent machine tools have a tendency to increase speed in order to improve machining efficiency. For this reason, the heat generated from the bearing that supports the main shaft is also increasing as the speed increases. In addition, so-called motor built-in types in which a driving motor is incorporated in the apparatus are becoming more and more a cause of heat generation of the apparatus.

¡The temperature rise of the bearing due to heat generation results in an increase in the preload, and we want to suppress it as much as possible considering the speed and accuracy of the spindle. As a method of suppressing the temperature rise of the main shaft device, there is a method of cooling the shaft and the bearing by sending compressed air for cooling to the bearing (for example, Patent Document 1). In Patent Document 1, cold air is injected into the space between the two bearings at an angle in the rotational direction to form a swirling flow. Thereby, the shaft and the bearing are cooled.

Further, Patent Document 2 describes a cooling structure in which the above-described cooling method using compressed air is applied to a grease lubricated bearing device. In that case, in order to prevent the grease in the bearing from being blown away by the compressed air, it has been proposed to provide an obstacle wall that prevents the compressed air from flowing into the bearing space.

Japanese Patent Laying-Open No. 2015-183738 JP 2014-062619 A

Since the cooling method using compressed air described above has a high cooling effect, the temperature rise of the spindle device can be effectively suppressed. Further, like the cooling structure of Patent Document 2, by providing an obstacle wall that prevents the compressed air from flowing into the bearing space, the cooling method using the compressed air can be applied to the grease lubricated bearing device. Become. However, the obstacle wall proposed in Patent Document 2 has a function of preventing compressed air from flowing into the bearing space, but does not have a function of suppressing exhaust. For this reason, the compressed air blown toward the outer peripheral surface of the inner ring spacer does not stay for a long time between the inner ring spacer and the outer ring spacer, and is discharged in a relatively short time. As a result, it is difficult to obtain a sufficient cooling effect.

An object of the present invention is to provide a cooling structure capable of preventing grease in a bearing from being blown off by compressed air and efficiently cooling the bearing device by compressed air in a grease lubricated bearing device. .

In the cooling structure of the bearing device according to the present invention, an outer ring spacer and an inner ring spacer are respectively 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 cooling structure of the bearing device, the inner ring and the inner ring spacer are fitted to a main shaft, and the rolling bearing is lubricated by grease sealed in a bearing space between the outer ring and the inner ring.

In the cooling structure of this bearing device, a supply port for supplying compressed air for cooling toward the outer peripheral surface of the inner ring spacer is provided on the inner peripheral surface of the outer ring spacer, and the axial end surface of the outer ring spacer In addition, an exhaust port for compressed air supplied from the supply port is provided.
At both ends of the inner ring spacer in the axial direction, obstacle walls are provided that prevent the compressed air supplied from the supply port from flowing into the bearing space and projecting to the outer diameter side. A part of the obstacle wall faces the outer ring spacer via a minute gap to constitute a first labyrinth seal that inhibits a smooth flow of compressed air from the supply port to the exhaust port.

According to this configuration, the compressed air for cooling supplied from the supply port is blown onto the outer peripheral surface of the inner ring spacer, whereby the inner ring spacer is cooled, and the inner ring of the rolling bearing in contact therewith is also cooled. Thereafter, the compressed air flows to both sides in the axial direction along the outer peripheral surface of the inner ring spacer. Although rolling bearings are arranged on both sides in the axial direction, obstacle walls are provided at both axial ends of the inner ring spacer, so that compressed air is prevented from flowing into the bearing space. Since a part of the obstacle wall is configured as the first labyrinth seal, the exhaust of compressed air is suppressed, and the compressed air after being blown to the outer peripheral surface of the inner ring spacer causes the inner ring spacer and the outer ring spacer to The time to stay in the space between them becomes longer. As a result, the inner ring spacer can be efficiently cooled. Thereby, the bearing device and the main shaft are efficiently cooled.

Further, as described above, since the compressed air is prevented from flowing into the bearing space by the obstacle wall, the grease sealed in the bearing space is prevented from being blown off by the compressed air. Thereby, a favorable lubrication state can be maintained.

In this invention, the obstacle wall may constitute the first labyrinth seal by a plurality of portions facing the outer ring spacer via a minute gap. In this case, exhaust of the compressed air is further suppressed, and the time during which the compressed air stays in the space between the inner ring spacer and the outer ring spacer is further increased.

In this invention, the rolling bearing has a sealing material that seals the bearing space at an axial end of the outer ring, an end surface of the obstacle wall faces the sealing material in the axial direction, and the sealing material and the obstacle The wall may constitute a second labyrinth seal that inhibits the compressed air from flowing into the bearing space. As a result, the compressed air is less likely to flow into the bearing space.

In the present invention, the gap is positioned on the inner side in the axial direction than the exhaust port, and an axial portion between the gap and the exhaust port on the inner peripheral surface of the outer ring spacer faces the exhaust port. It may be a tapered portion where the inner diameter dimension gradually increases. When the axial portion on the inner peripheral surface of the outer ring spacer is a tapered portion, the compressed air after passing through the gap flows smoothly to the exhaust port. Therefore, exhaust is performed quickly. This makes it difficult for compressed air to flow into the bearing space of the rolling bearing, and the grease sealed in the bearing space is held for a long period of time.

In the present invention, the supply port may be provided to be inclined forward in the rotational direction of the inner ring, and the exhaust port may be provided to be inclined forward in the rotational direction of the outer ring spacer.

The cooling by the compressed air of the above-mentioned patent document 1 can be applied to so-called air oil lubrication or oil mist lubrication in which a lubricant is mixed with compressed air to lubricate a rolling bearing. In this case, if the amount of compressed air passing through the inside of the bearing is excessive, smooth supply / exhaust of air oil may be hindered. Moreover, there is a possibility that noise will increase when compressed air collides with an air curtain-like air flow film generated near the shaft end of the rolling bearing or the rotating rolling element during rotation.
Cooling with compressed air can also be applied when the bearing is grease lubricated. In that case, if the amount of compressed air passing through the inside of the bearing is large, the compressed air may discharge the grease inside the bearing and induce poor lubrication.

According to the above configuration, the compressed air for cooling is discharged from the supply port provided in the outer ring spacer toward the peripheral surface of the inner ring spacer. Since the supply port is inclined forward in the rotation direction of the rotary spacer, the compressed air discharged from the supply port flows in the axial direction while turning along the peripheral surface of the inner ring spacer, Cool the seat. Since the compressed air turns, the time during which the compressed air is in contact with the peripheral surface of the inner ring spacer is longer than when the compressed air flows straight in the axial direction. As a result, the inner ring spacer can be efficiently cooled.

Compressed air that has passed through the peripheral surface of the inner ring spacer is discharged to the outside through an exhaust port provided in the axial end surface of the outer ring spacer. Since the exhaust port is also inclined forward in the rotational direction of the inner ring spacer, the compressed air that is turning is smoothly discharged from the exhaust port. Thereby, the amount of compressed air passing through the inside of the rolling bearing can be reduced. As a result, it is possible to eliminate or reduce adverse effects caused by a large amount of compressed air flowing inside the rolling bearing.

Specifically, when air-oil lubrication or oil mist lubrication is performed on a rolling bearing, it is possible to prevent obstructing smooth air supply and exhaust such as air oil. Furthermore, it is possible to suppress noise caused by collision of compressed air with an air curtain-like air flow film generated near the shaft end of the rolling bearing or a rotating rolling element. Further, when the rolling bearing is grease lubricated, it is possible to prevent the compressed air from discharging the grease inside the bearing.

In the present invention, the plurality of supply ports and the same number of exhaust ports may be provided, and the nozzle holes and the exhaust ports may be provided at equal intervals in the circumferential direction. In this case, the inner ring spacer can be evenly cooled in the circumferential direction by the compressed air discharged from the nozzle hole. Further, the compressed air that has passed through the circumferential surface of the inner ring spacer is discharged uniformly from each exhaust port. For this reason, discharge of compressed air is performed smoothly.

When a plurality of the supply ports and the exhaust ports are provided, the circumferential distance from any supply port to the exhaust port located on the front side in the rotation direction of the inner ring spacer with respect to the supply port is It may be longer than the distance in the circumferential direction from the exhaust port to the supply port located on the front side in the rotational direction of the inner ring spacer. With such a positional relationship between the nozzle hole and the exhaust port, the time during which the compressed air is in contact with the peripheral surface of the rotating spacer is long, and the cooling effect is high.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the invention.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same part numbers in a plurality of drawings indicate the same or corresponding parts.
It is sectional drawing of the bearing apparatus provided with the cooling structure which concerns on 1st Embodiment of this invention. It is the elements on larger scale of FIG. It is sectional drawing which cut | disconnected the inner ring | wheel spacer and the outer ring | wheel spacer of the same bearing apparatus by the plane perpendicular | vertical to an axial direction. It is the figure which expanded and represented a part of outer ring spacer of the same bearing device. It is sectional drawing of the bearing apparatus provided with the cooling structure which concerns on 2nd Embodiment of this invention. It is the elements on larger scale of FIG. It is sectional drawing of the bearing apparatus provided with the cooling structure which concerns on 3rd Embodiment of this invention. It is the elements on larger scale of FIG. FIG. 9 is a cross-sectional view of an inner ring spacer and an outer ring spacer of a bearing device different from the bearing devices of FIGS. 1 to 8 cut along a plane perpendicular to the axial direction. It is sectional drawing which shows the state which integrated the bearing apparatus shown in FIG. 1 in the main shaft apparatus of a machine tool. It is sectional drawing which cut | disconnected the inner ring | wheel spacer and the outer ring | wheel spacer of the bearing apparatus which concerns on 4th Embodiment of this invention by the plane perpendicular | vertical to an axial direction. It is sectional drawing of the machine tool spindle apparatus provided with the cooling structure of the bearing apparatus which concerns on the 1st application example of this invention. It is an expanded sectional view of the principal part of the bearing device. It is the figure which expanded and represented a part of outer ring spacer of the same bearing device. FIG. 13 is a sectional view taken along the line XV-XV in FIG. 12. It is sectional drawing of the principal part of the cooling structure of the bearing apparatus which concerns on the 2nd application example of this invention. It is XVII-XVII sectional drawing of FIG. It is sectional drawing of the principal part of the cooling structure of the bearing apparatus which concerns on the 3rd application example of this invention. It is the elements on larger scale of FIG.

[First Embodiment]
A cooling structure for 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 J includes two rolling bearings 1, 1 arranged in the axial direction, and an outer ring spacer 4 interposed between outer rings 2, 2 of the two rolling bearings 1, 1. And an inner ring spacer 5 interposed between the inner rings 3 and 3. The rolling bearing 1 of this embodiment is an angular ball bearing. The two rolling bearings 1 and 1 are installed in a rear combination. A plurality of rolling elements 8 are interposed between the raceway surface of the outer ring 2 and the raceway surface of the inner ring 3. The rolling elements 8 are held at equal intervals in the circumferential direction by a cage 9. The rolling bearing 1 is grease-lubricated, and seal materials 31 and 32 are attached to both ends of the outer ring 2 in the axial direction. The sealing materials 31 and 32 seal the bearing space 30 between the outer ring 2 and the inner ring 3.

This bearing device J is used, for example, to support the spindle of a machine tool. In that case, the outer ring 2 of each rolling bearing 1 is fixed in the housing 6, and the inner ring 3 is fitted to the outer peripheral surface of the main shaft 7.

The cooling structure of the bearing device J will be described.
As shown in FIG. 1, the outer ring spacer 4 has a substantially T-shaped cross section. Specifically, the outer ring spacer 4 includes an inner diameter side protruding portion 4a that is a T-shaped vertical line portion and a cylindrical portion 4b that is a T-shaped horizontal line portion. The inner peripheral surface of the inner diameter side protrusion 4 a and the outer peripheral surface of the inner ring spacer 5 are opposed to each other with a radial gap 9 therebetween. A supply port 10 is provided on the inner peripheral surface of the inner diameter side protrusion 4 a of the outer ring spacer 4. The supply port 10 supplies the compressed air A for cooling toward the outer peripheral surface of the inner ring spacer 5. In this example, as shown in FIG. 3, the number of supply ports 10 is three, and each supply port 10 is arranged at equal intervals in the circumferential direction.

1 and 3, an annular introduction groove 11 for introducing the compressed air A is provided on the outer peripheral surface of the outer ring spacer 4. The introduction groove 11 is provided in an intermediate portion in the axial direction on the outer peripheral surface of the outer ring spacer 4 and communicates with each supply port 10 through a connection hole 11a. Compressed air A is supplied to the introduction groove 11 from the compressed air supply device 45 (FIG. 10) provided outside the bearing device J through the compressed air introduction hole 46 (FIG. 3) provided in the housing 6.

As shown in FIG. 1, the inner ring spacer 5 has a cylindrical body 13 at the center in the axial direction and obstacle wall forming bodies 14 and 14 on both sides in the axial direction of the cylindrical body 13. A barrier wall 15 is provided at the axial end of each barrier wall forming body 14. The main body portion 14 a excluding the obstacle wall 15 in the obstacle wall forming body 14 has a cylindrical shape having the same outer diameter as that of the cylindrical body 13.

FIG. 2 is a partially enlarged view of FIG. As shown in FIG. 2, the obstacle wall 15 includes a flange-shaped portion 15 a that extends to the outer diameter side, and a cylindrical portion 15 b that extends axially inward from the outer diameter end of the flange-shaped portion 15 a. The outer diameter end of the collar portion 15 a extends to the vicinity of the inner peripheral surface of the outer ring 2 of the rolling bearing 1. The axially inner end of the cylindrical portion 15 b is opposed to the inner diameter side protruding portion 4 a of the outer ring spacer 4 via a minute gap 16. A first labyrinth seal LS is configured by a facing portion between the cylindrical portion 15 b and the inner-diameter side protruding portion 4 a of the outer ring spacer 4.

An annular cooling space 18 is formed by the main body portion 14 a of the obstacle wall forming body 14, the flange portion 15 a of the obstacle wall 15, the cylindrical portion 15 b, and the inner diameter side protruding portion 4 a of the outer ring spacer 4. An exhaust space 19 is formed between the outer peripheral surface of the cylindrical portion 15 b of the obstacle wall 15 and the inner peripheral surface of the cylindrical portion 4 b of the outer ring spacer 4. The cooling space 18 and the exhaust space 19 communicate with each other through a gap 16 that constitutes the first labyrinth seal LS.

An exhaust port 20 is provided at the axial end of the cylindrical portion 4 b of the outer ring spacer 4. The exhaust port 20 has, for example, a rectangular cutout shape as shown in FIG. By disposing the outer ring 2 of the rolling bearing 1 adjacent to the outer ring spacer 4, the exhaust space 19 shown in FIG. 2 and the outside of the bearing device J are communicated with each other through the exhaust port 20.

1, the bearing space 30 and the cooling space 18 are completely separated by the obstacle wall 15. The outer diameter end of the flange portion 15a of the obstacle wall 15 extends to the vicinity of the inner peripheral surface of the outer ring 3, and the flange portion 15a of the obstacle wall 15 is slightly axially spaced from the sealing material 31 on the inner side in the axial direction. Is facing through. Thereby, a second labyrinth seal is formed between the bearing space 30 and the exhaust space 19.

During operation of the bearing device J, the compressed air A for cooling is sent from the compressed air supply device outside the bearing device J to the introduction groove 11 of the outer ring spacer 4 and from the supply port 10 of the outer ring spacer 4 to the inner ring spacer. 5 is supplied toward the outer peripheral surface. Thereby, the inner ring spacer 5 is cooled, and the inner ring 3 of the rolling bearing 1 in contact therewith is also cooled. Thereafter, the compressed air A flows along the outer peripheral surface of the inner ring spacer 5 on both sides in the axial direction. Although the rolling bearings 1 are arranged on both sides in the axial direction, since the obstacle walls 15 are provided at both axial ends of the inner ring spacer 5, the compressed air A hardly flows into the bearing space 30.

Further, since a part of the obstacle wall 15 constitutes the first labyrinth seal LS, the exhaust of the compressed air A blown to the outer peripheral surface of the inner ring spacer 5 is suppressed. As a result, the time during which the compressed air A stays in the cooling space 18 becomes long, and the inner ring spacer 5 can be efficiently cooled. Thereby, the inner ring spacer 5 and the inner ring 3 of the rolling bearing 1 in contact therewith are more efficiently cooled.

Compressed air A in the cooling space 18 gradually passes through the gap 16 to the exhaust space 19 over time, and is discharged from the exhaust space 19 to the outside of the bearing device J through the exhaust port 20.

Since the obstacle wall 15 is provided, the compressed air A does not flow directly from the cooling space 18 into the bearing space 30. A second labyrinth seal is formed between the bearing space 30 and the exhaust space 19. For this reason, the compressed air A hardly flows into the bearing space 30, and the grease enclosed in the bearing space 30 can be prevented from being blown off by the compressed air A. As a result, a good lubrication state of the bearing device J can be maintained.

[Second Embodiment]
5 and 6 show a cooling structure for a bearing device according to a second embodiment of the present invention.
The bearing device J of the second embodiment has the same configuration as that of the first embodiment except that the shape of the obstacle wall 15 of the inner ring spacer 5 is different. Parts having the same configuration are denoted by the same reference numerals and description thereof is omitted.

The obstacle wall 15 of the bearing device J of the second embodiment has two cylindrical portions 15b and 15c. One cylindrical portion 15b extends inward in the axial direction from the outer diameter end of the collar portion 15a. The other cylindrical portion 15c extends inward in the axial direction from a position on the inner diameter side of the outer diameter end of the collar-shaped portion 15a. The axially inner ends of the cylindrical portions 15b and 15c face the inner diameter side protruding portion 4a of the outer ring spacer 4 through minute gaps 16 and 17, respectively. A first labyrinth seal LS is configured by the facing portions of the two cylindrical portions 15b and 15c and the inner diameter side protruding portion 4a of the outer ring spacer 4.

Thus, having two opposing portions increases the function as the first labyrinth seal LS and further increases the time that the compressed air A stays in the cooling space 18. Therefore, the inner ring spacer 5 can be cooled more efficiently. Thereby, the inner ring spacer 5 and the inner ring 3 of the rolling bearing 1 in contact with the inner ring spacer 5 are more efficiently cooled.

[Third Embodiment]
7 and 8 show a cooling structure for a bearing device according to a third embodiment of the present invention.
The bearing device J of the third embodiment differs from the first embodiment in the shape of the axial portion between the clearance 16 and the exhaust port 20 on the inner peripheral surface of the outer ring spacer 4. In other words, this axial portion constitutes a tapered portion 23 whose inner diameter dimension gradually increases toward the outer side (exhaust port 20) in the axial direction over the entire circumference. The taper angle θ is, for example, 10 ° to 60 °. Other configurations are the same as those in the first embodiment. Parts having the same configuration are denoted by the same reference numerals and description thereof is omitted.

As described above, when the axial portion on the inner peripheral surface of the outer ring spacer 4 is the tapered portion 23, the compressed air A that has passed through the gap 16 flows smoothly to the exhaust port 20, and the exhaust is performed quickly. . As a result, the compressed air A is less likely to flow into the bearing space 30 of the rolling bearing 1, and the grease sealed in the bearing space 30 is retained for a long period of time.

Regarding the bearing device (FIG. 1) having a cylindrical shape in the axial direction and the bearing device in FIG. 7 having a tapered shape, the amount of compressed air discharged to the outside of the bearing and the amount of compressed air flowing into the bearing by fluid analysis. Was calculated. The taper angle θ of the tapered portion 23 was set to 15 °. The results are shown in Table 1.

From the results in Table 1, it can be seen that the bearing device having a tapered shape has a larger discharge amount to the outside of the bearing and a smaller inflow amount to the inside of the bearing than the bearing device having the cylindrical portion in the axial direction.

[Different bearing devices]
When the rotation direction of the shaft supported by the bearing device J is constant like the main shaft of the machine tool, the air discharge direction of each supply port 10 is changed to the inner ring 3 (FIG. 1) and the main shaft as shown in FIG. 7 may be inclined forward in the rotational direction D1. Each supply port 10 is linear, and is offset from an arbitrary radial straight line L1 in a cross section perpendicular to the axis of the outer ring spacer 4 in a direction orthogonal to the straight line L1 (offset amount OS). is there. Thus, when the air discharge direction of each supply port 10 is inclined, when the discharged compressed air A hits the outer peripheral surface of the inner ring spacer 5, the pressing force of the compressed air A can be applied to the inner ring spacer 5. it can. Thereby, the effect | action which drives the main axis | shaft 7 can be anticipated.

[Machine tool spindle]
FIG. 10 is a cross-sectional view showing a part of the spindle device of the machine tool in which the bearing device J shown in FIG. 1 is incorporated. In the bearing device J, the outer rings 2, 2 of the rolling bearings 1, 1 and the outer ring spacer 4 are fitted to the inner peripheral surface of the housing 6, and the inner rings 3, 3 and the inner ring spacer 5 of the rolling bearings 1, 1 are machine tools. The main shaft 7 is fitted on the outer peripheral surface.

In this example, the outer ring 2 and the outer ring spacer 4 are fitted to the housing 6 with a clearance, and the inner ring 3 and the inner ring spacer 5 are fitted to the shaft 7. The outer ring 3 of one (right side of the drawing) of the rolling bearing 1 is axially positioned by the step portion 6 a of the housing 6, and the inner ring 3 of the one (right side of the drawing) is axially positioned by the positioning spacer 41. Positioning has been performed. The bearing device J is fixed to the housing 6 by pressing the outer ring presser 42 and the inner ring presser 43 against the outer ring 2 and the inner ring 3 of the other (left side in the drawing) of the rolling bearing 1. However, the fixing method of the bearing device J is not limited to this.

The housing 6 and the outer ring retainer 42 are provided with a compressed air introduction hole 46 for introducing the compressed air A for cooling from the compressed air supply device 45 into the bearing device J. The compressed air introduction hole 46 communicates with the introduction groove 11 provided on the outer peripheral surface of the outer ring spacer 4. Further, an exhaust hole 47 is provided in the housing 6 and the outer ring retainer 42. The exhaust hole 47 communicates with the exhaust port 20 of the outer ring spacer 4 through the connection hole 48.

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

[Fourth Embodiment]
FIG. 11 shows a cooling structure for a bearing device according to a fourth embodiment of the present invention. In the fourth embodiment, the supply port 10 for supplying the compressed air for cooling to the outer peripheral surface of the inner ring spacer 5 is constituted by the nozzle hole 60 a of the nozzle 60. The nozzle hole 60a is inclined forward in the rotational direction D1 of the inner ring spacer 5. The exhaust port 20 is also inclined forward in the rotational direction D1 of the inner ring spacer 5.

Thus, since the nozzle hole 60a is inclined forward in the rotation direction D1 of the inner ring spacer 5, the compressed air A discharged from the nozzle hole 60a is swung along the peripheral surface of the inner ring spacer 5. It flows in the axial direction, and the inner ring spacer 5 is cooled during this time. Since the compressed air A turns, the time during which the compressed air A is in contact with the peripheral surface of the inner ring spacer 5 is longer than when the compressed air A flows straight in the axial direction. As a result, the inner ring spacer 5 can be efficiently cooled.

Compressed air A that has passed through the peripheral surface of the inner ring spacer 5 is discharged to the outside through the exhaust port 20 provided in the axial end surface of the outer ring spacer 4 and the inside of the rolling bearing 1. Since the exhaust port 20 is also inclined forward in the rotation direction D <b> 1 of the inner ring spacer 5, the compressed air A that is a swirling flow is smoothly discharged from the exhaust port 20. Thereby, the amount of the compressed air A passing through the inside of the rolling bearing 1 can be reduced, and adverse effects caused by a large amount of the compressed air A flowing inside the rolling bearing 1 can be eliminated or reduced.

Specifically, when the rolling bearing 1 is subjected to air oil lubrication or oil mist lubrication, it is possible to prevent obstructing the smooth supply and exhaust of air oil. In addition, it is possible to suppress noise caused by the collision of the compressed air A with the air curtain-like air flow film generated in the vicinity of the shaft end of the rolling bearing 1 or the rotating rolling element 8. Further, when the rolling bearing 1 is grease lubricated, it is possible to prevent the compressed air A from discharging grease inside the bearing.

Furthermore, in the fourth embodiment, three nozzle holes 60a and three exhaust ports 20 are provided, and these nozzle holes 60a and exhaust ports 20 are arranged at equal intervals in the circumferential direction. According to this configuration, the inner ring spacer 5 can be evenly cooled in the circumferential direction by the compressed air A discharged from the nozzle hole 60a. Further, the compressed air A that has passed through the peripheral surface of the inner ring spacer 5 is evenly discharged from each exhaust port 20. For this reason, the compressed air A is discharged smoothly.

Furthermore, in the fourth embodiment, a circle from any one of the three nozzle holes 60a to the exhaust port 20 located on the front side in the rotation direction D1 of the inner ring spacer 5 with respect to the nozzle hole 60a. The circumferential distance M is longer than the circumferential distance N from the exhaust port 20 to the nozzle hole 60a located on the front side in the rotational direction D1 of the inner ring spacer 5. With such a positional relationship between the nozzle hole 60a and the exhaust port 20, the time during which the compressed air A is in contact with the peripheral surface of the inner ring spacer 5 becomes long, and the cooling effect is high.

As described above, the preferred embodiments have been described with reference to the drawings. However, the present invention is not limited to the above embodiments, and various additions and modifications can be made without departing from the gist of the present invention. Or it can be deleted. Therefore, such a thing is also included in the scope of the present invention.

In the first to fourth embodiments described above, the cooling structure of the bearing device provided with the first labyrinth seal LS has been described. However, the present invention can also be applied to a case where the first labyrinth seal LS is not provided.

[First application example]
12 to 15 show a cooling structure for a bearing device according to a first application example of the present invention. The bearing device cooling structure of the first application example is applied to a spindle device of a machine tool. However, it is not limited only to the spindle device of the machine tool.

As shown in FIG. 12, the bearing device J includes two rolling bearings 101, 101 arranged in the axial direction. An outer ring spacer 104 is interposed between the outer rings 102 and 102 of the rolling bearings 101 and 101, and an inner ring spacer 105 is interposed between the inner rings 103 and 103. The outer ring 102 and the outer ring spacer 104 are installed in the housing 106, and the inner ring 103 and the inner ring spacer 105 are fitted to the main shaft 107.

The rolling bearing 101 in this example is an angular ball bearing, and a plurality of rolling elements 108 are interposed between the raceway surface of the outer ring 102 and the raceway surface of the inner ring 103. Each rolling element 108 is held at equal intervals in the circumferential direction by a cage 109. The two rolling bearings 101, 101 are arranged in combination with each other on the back surface. The initial preload of each of the rolling bearings 101 and 101 is set according to the width dimension difference between the outer ring spacer 104 and the inner ring spacer 105.

The rolling bearing 101 of the first application example is an inner ring rotating type. That is, the outer ring 102 corresponds to a “fixed side raceway”, and the inner ring 103 corresponds to a “rotation side raceway”. The outer ring spacer 104 corresponds to a “fixed side spacer”, and the inner ring spacer 105 corresponds to a “rotation side spacer”. Further, the main shaft 107 corresponds to a “rotating member”, and the housing 106 corresponds to a “fixing member”. The same applies to other application examples described later.

In the first application example, the outer rings 102 and 102 and the outer ring spacer 104 are fitted into the housing 106 with a clearance, and the axial positioning is performed by the step 106a of the housing 106 and the end surface lid 140. The inner rings 103, 103 and the inner ring spacer 105 are interference-fitted to the main shaft 107, and are positioned in the axial direction by positioning spacers 141, 142 on both sides in the axial direction. The left positioning spacer 142 in FIG. 12 is fixed by a nut 143 screwed to the main shaft 107. The fixing method of the outer rings 102 and 102, the outer ring spacer 104, the inner rings 103 and 103, and the inner ring spacer 105 is not limited to this.

The cooling structure will be described.
FIG. 13 is an enlarged cross-sectional view showing the main part of the cooling structure of the bearing device. The outer ring spacer 104 includes an outer ring spacer main body 111 and ring-shaped lubricating nozzles 112 and 112 made of a member different from the outer ring spacer main body 111. The outer ring spacer main body 111 has a substantially T-shaped cross section. Lubricating nozzles 112 and 112 are respectively fixed to both sides of the outer ring spacer body 111 in the axial direction. The lubricating nozzles 112, 112 are arranged symmetrically with respect to the axial center of the outer ring spacer body 111.

The inner diameter of the outer ring spacer body 111 is larger than the inner diameter of the lubricating nozzles 112, 112. As a result, a recess 113 formed by the inner peripheral surface of the outer ring spacer main body 111 and the side surfaces of the lubricating nozzles 112, 112 following the inner peripheral surface is formed on the inner peripheral surface of the outer ring spacer 104. Yes. The recessed portion 113 is an annular groove having a rectangular cross-sectional shape. The inner peripheral surface of the outer ring spacer 104 other than the recess 113, that is, the inner peripheral surface of the lubricating nozzles 112 and 112, and the outer peripheral surface of the inner ring spacer 105 are opposed to each other with a minute radial gap δa. . Thus, an annular space 114 having a larger radial width than the others is formed between the recess 113 and the outer peripheral surface of the inner ring spacer 105.

The outer ring spacer main body 111 is provided with a nozzle hole 115 for discharging compressed air A for cooling toward the outer peripheral surface of the inner ring spacer 105. The outlet 115 a of the nozzle hole 115 is open to a recess 113 on the inner peripheral surface of the outer ring spacer 104. In this example, three nozzle holes 115 are provided, and the nozzle holes 115 are arranged at equal intervals in the circumferential direction. The number of nozzle holes 115 is not limited to three.

As shown in FIG. 15 which is an XV-XV sectional view of FIG. 12, each nozzle hole 115 is inclined forward in the rotational direction D1 of the inner ring spacer 105. That is, each nozzle hole 115 is at a position offset from an arbitrary radial straight line L in a cross section perpendicular to the axis of the outer ring spacer 104 in a direction perpendicular to the straight line L. By offsetting the nozzle hole 115, the compressed air A acts as a swirling flow in the rotation direction D1 of the inner ring spacer 105, thereby improving the cooling effect. In FIGS. 12 and 13, the outer ring spacer 104 is displayed in a cross section passing through the center line of the nozzle hole 115.

An introduction groove 116 for introducing the compressed air A into each nozzle hole 115 from the outside of the bearing is formed on the outer peripheral surface of the outer ring spacer main body 111. The introduction groove 116 is provided in an intermediate portion in the axial direction on the outer peripheral surface of the outer ring spacer 104, and is formed in an arc shape communicating with each nozzle hole 115. The introduction groove 116 is provided over an angular range indicating most of the outer circumferential surface of the outer ring spacer main body 111 in the circumferential direction. An air oil supply path (not shown), which will be described later, is provided at a circumferential position where the introduction groove 116 is not formed on the outer peripheral surface of the outer ring spacer main body 111. As shown in FIG. 12, the housing 106 is provided with a compressed air introduction path 145, and the introduction groove 116 communicates with the compressed air introduction path 145. An air supply device (not shown) that supplies the compressed air A to the compressed air introduction hole 145 is provided outside the housing 106.

The lubrication structure will be described.
The lubrication nozzles 112, 112 of the outer ring spacer 104 shown in FIG. 12 supply air oil to the inside of the rolling bearing 101. Each of the lubricating nozzles 112 has a tip portion 130 that protrudes into the bearing. The tip portion 130 faces the outer peripheral surface of the inner ring 103 via an annular gap δb. The annular gap δb constitutes a passage for air oil passage. In other words, the tip portion 130 of the lubricating nozzle 112 is disposed so as to enter the bearing so as to cover the outer peripheral surface of the inner ring 103. The tip portion 130 of the lubricating nozzle 112 is disposed radially inward from the inner peripheral surface of the cage 109.

As shown in FIG. 13, the lubrication nozzle 112 is provided with an air oil supply hole 131 for supplying air oil to the annular gap δb. The air oil supply hole 131 is inclined toward the inner diameter side toward the bearing side, and an outlet thereof opens to the inner surface of the tip portion 130. Air oil is supplied to the air oil supply hole 131 through an air oil supply path (not shown) provided in the housing 106 and the outer ring spacer main body 111. An annular recess 103 a is provided at a location facing the air oil supply hole 131 on the outer peripheral surface of the inner ring 103.

The oil of the air oil discharged from the lubricating nozzle 112 is accumulated in the annular recess 103a and is guided to the bearing center side along the inclined outer peripheral surface of the inner ring 103 by the centrifugal force accompanying the rotation of the inner ring 103.

The exhaust structure will be described.
An exhaust port 117 is provided at the axial end of the outer ring spacer main body 111. The exhaust port 117 has, for example, a rectangular cutout shape as shown in the development view of FIG. By arranging the outer ring 102 of the rolling bearing 101 adjacent to the outer ring spacer main body 111, the exhaust port 117 constitutes an opening that communicates the inside and the outside of the bearing device J. The number of the exhaust ports 117 is the same as that of the nozzle holes 115 (three in this example). Similar to the nozzle holes 115, the exhaust ports 117 are provided at equal intervals in the circumferential direction. Further, similarly to the nozzle hole 115, the exhaust port 117 is inclined forward in the rotational direction D <b> 1 of the inner ring spacer 105.

In FIG. 13, the nozzle hole 115 and the exhaust port 117 are shown in the same cross section, but actually, as shown in FIG. 15, the positions of the nozzle hole 115 and the exhaust port 117 are shifted in the circumferential direction. The positional relationship in the circumferential direction between the nozzle hole 115 and the exhaust port 117 is as follows.

The distance M in the circumferential direction from the outlet 115a of any one nozzle hole 115 to the exhaust port 117 located on the front side in the rotational direction D1 of the inner ring spacer 105 with respect to the nozzle hole 115 is defined as a distance M. A distance N in the circumferential direction from any one exhaust port 117 to the outlet 115a of the nozzle hole 115 positioned in front of the exhaust port 117 in the rotation direction D1 of the inner ring spacer 105 is defined as a distance N. In this case, the distance M is longer than the distance N. Here, the position of the nozzle hole 115 is the circumferential position at the center of the outlet 115 a, and the position of the exhaust port 117 is the central position in the circumferential direction of the inner diameter end of the exhaust port 117. By arranging the nozzle hole 115 and the exhaust port 117 in this manner, the compressed air A can be retained in the bearing device J for a long time.

As shown in FIG. 12, the housing 106 is provided with an exhaust passage 146 for exhausting the compressed air for cooling and the air oil for lubrication from the bearing device J. The exhaust path 146 includes a radial exhaust hole 148 that communicates with the exhaust port 117, and an axial exhaust hole 149 that communicates with the radial exhaust hole 148.

The effect | action of the cooling structure of the bearing apparatus of a 1st application example is demonstrated.
Cooling compressed air A is blown toward the outer peripheral surface of the inner ring spacer 105 from the nozzle hole 115 provided in the outer ring spacer 104. At this time, the compressed air A is adiabatically expanded by being discharged from the narrow nozzle hole 115 to the wide space 114. The volume of compressed air in the nozzle hole 115 is V1, the temperature is T1, the volume of compressed air in the space 114 is V2, and the temperature is T2. In this case, from the gas equation of state and the first law of thermodynamics, V1 <V2 and T1> T2. That is, in the space 114, the temperature increases as the temperature of the compressed air A decreases. As the volume increases, the flow rate of the compressed air A increases. Thus, the inner ring spacer 105 can be efficiently cooled by blowing the high-speed compressed air A at a low temperature onto the inner ring spacer 105.

Compressed air A is led out from the gap δa and the gap δb. Specifically, the compressed air A flows outward in the axial direction along the outer peripheral surface of the inner ring spacer 105 and the outer peripheral surface of the inner ring 103. Also during this time, the inner ring spacer 105 and the inner ring 103 are cooled by the compressed air A. Since the nozzle hole 115 is inclined forward in the rotational direction D 1 of the inner ring spacer 105, the compressed air A flows in the axial direction while turning along the outer peripheral surface of the inner ring spacer 105 and the outer peripheral surface of the inner ring 103. When flowing in the axial direction while turning, the time during which the compressed air A is in contact with the outer peripheral surface of the inner ring spacer 105 and the outer peripheral surface of the inner ring 103 becomes longer than when the air flows straight in the axial direction.

Furthermore, since the nozzle hole 115 and the exhaust port 117 are arranged so that the circumferential distance M is larger than the distance N as described above, the compressed air A stays in the bearing device J for a long time. . As a result, the inner ring spacer 105 and the inner ring 103 can be cooled more efficiently.

Compressed air A that has passed through the outer peripheral surface of the inner ring spacer 105 and the outer peripheral surface of the inner ring 103 is discharged to the outside through the exhaust port 117 on the axial end surface of the outer ring spacer 104 and the inside of the rolling bearing 101. Similarly to the nozzle hole 115, the exhaust port 117 is inclined forward in the rotational direction D <b> 1 of the inner ring spacer 105, so that the compressed air A that is a swirling flow is smoothly discharged from the exhaust port 117. Thereby, the amount of compressed air A passing through the inside of the rolling bearing 101 can be reduced. As a result, it is possible to eliminate or reduce adverse effects caused by a large amount of the compressed air A flowing inside the rolling bearing 101.

As in the first application example, when the rolling bearing 101 is air-oil lubricated, it is possible to prevent obstructing the smooth supply and exhaust of air oil. Further, as in the first application example, when the tip portion 130 of the lubricating nozzle 112 enters the bearing, noise due to the compressed air A colliding with the rotating rolling element 108 can be reduced.

Since the nozzle holes 115 and the exhaust ports 117 are the same number, and the nozzle holes 115 and the exhaust ports 117 are provided at equal intervals in the circumferential direction, the inner ring spacer 105 is compressed by the compressed air A discharged from the nozzle holes 115. And the inner ring | wheel 103 can be cooled equally in the circumferential direction. Further, the compressed air A that has passed through the outer peripheral surface of the inner ring spacer 105 and the outer peripheral surface of the inner ring 103 is discharged uniformly from the exhaust ports 117. For this reason, the discharge of the compressed air A becomes even smoother.

[Second application example]
16 and 17 show a second application example of the present invention. The bearing device J of the second application example also lubricates the rolling bearing 101 with air oil. However, the second application example is different from the first application example in which the outer ring spacer 104 includes the outer ring spacer main body 111 and a ring-shaped lubricating nozzle 112 which is a separate member, as shown in FIG. 104 is an integral type. The integral outer ring spacer 104 is provided with a nozzle hole 115 for discharging compressed air A and an air oil supply hole 131.

In the bearing device J of the second application example, a recess 113 (FIG. 13) like the outer ring spacer 104 of the first application example is formed on the inner peripheral surface of the outer ring spacer 104 where the outlet 115a of the nozzle hole 115 opens. It has not been. Instead, the inner ring spacer 105 is provided with a plurality of through holes 120 (10 in this example) at equal intervals in the circumferential direction. Each through-hole 120 is provided in the axially intermediate portion of the inner ring spacer 105. The through hole 120 has, for example, a round hole shape. Each through-hole 120 is also inclined forward in the rotational direction D1 of the inner ring spacer 105 toward the inner diameter side. By providing the through hole 120, a part of the compressed air A discharged from the nozzle hole 115 collides with the outer peripheral surface of the main shaft 107.

The air oil supply hole 131 opens in the side surface portion of the outer ring spacer 104 and faces the inside of the rolling bearing 101. Unlike the first application example, the portion provided with the air oil supply hole 131 in the outer ring spacer 104 does not protrude into the bearing. The air oil supply hole 131 is provided so that the air oil hits the vicinity of the boundary between the raceway surface of the inner ring 103 and the rolling element 8. Specifically, the axis AX of the air oil supply hole 131 is inclined toward the inner diameter side toward the rolling bearing 101. The air oil is supplied to the air oil supply hole 131 through a radial hole 121 (FIG. 17) provided in the outer ring spacer 104 from an air oil supply path (not shown) provided in the housing.

As in the first application example, an exhaust port 117 is provided on the end surface of the outer ring spacer 104 in the axial direction. The shape of the exhaust port 117 is the same as that of the first application example. The number of the exhaust ports 117 is the same as that of the nozzle holes 115 (three in this example). As shown in FIG. 17, the nozzle holes 115 and the exhaust ports 117 are provided at equal intervals in the circumferential direction. The nozzle hole 115 and the exhaust port 117 are inclined forward in the rotation direction D1 of the inner ring spacer 105. The positional relationship in the circumferential direction between the nozzle hole 115 and the exhaust port 117 is the same as that in the first application example.

In the cooling structure of the bearing device according to the second application example, the compressed air A for cooling is blown from the nozzle hole 115 to the outer peripheral surface of the inner ring spacer 105 to cool the inner ring spacer 105, and As the part passes through the through hole 120 of the inner ring spacer 105 and hits the main shaft 107, the main shaft 107 is directly cooled. Thereafter, the compressed air A flows along the outer peripheral surface of the inner ring spacer 105 to the outside in the axial direction. Since the nozzle hole 115 is inclined forward in the rotational direction D1 of the inner ring spacer 105, the compressed air A flows in the axial direction while turning along the outer peripheral surface of the inner ring spacer 105. Also during this time, the inner ring spacer 105 is cooled by the compressed air A.

Compressed air A after cooling the inner ring spacer 105 is discharged to the outside through the exhaust port 117 of the outer ring spacer 104 and the inside of the rolling bearing 101. Since the exhaust port 117 is also inclined forward in the rotational direction D1 of the inner ring spacer 105, the compressed air A that is a swirling flow is smoothly discharged from the exhaust port 117. Thereby, the amount of compressed air A passing through the inside of the rolling bearing 101 can be reduced. As a result, it is possible to eliminate or reduce adverse effects caused by a large amount of the compressed air A flowing inside the rolling bearing 1.

As in the second application example, when the rolling bearing 101 is air-oil lubricated, it is possible to prevent obstructing the smooth supply and exhaust of air oil. Further, as in the second application example, when a part of the outer ring spacer 104 does not protrude into the bearing, the compressed air A is applied to the air curtain-like air flow film generated near the shaft end of the rolling bearing 101 by rotation. Noise generated by the collision can be reduced.

In the first and second application examples described above, the example in which the rolling bearing 1 is air-oil lubricated has been described. However, the present invention can also be applied to a type in which the rolling bearing is grease lubricated.

[Third application example]
18 to 19 show a third application example. FIG. 18 is a sectional view of a bearing device that is grease lubricated, and FIG. 19 is a partially enlarged view thereof. The bearing device J of the third application example also includes a plurality of rolling bearings 101, 101 arranged in the axial direction, like the air-oil lubricated bearing devices of the first and second application examples. An outer ring spacer 104 is interposed between the outer rings 102 and 102 of the rolling bearings 101 and 101, and an inner ring spacer 105 is interposed between the inner rings 103 and 103. The rolling bearing 101 of the third application example is an angular ball bearing. A plurality of rolling elements 108 are interposed between the raceway surface of the outer ring 102 and the raceway surface of the inner ring 103. These rolling elements 108 are held at equal intervals in the circumferential direction by a cage 109. Further, in the bearing device J of the third application example that is grease lubrication, seal members 151 and 152 that seal the bearing internal space S1 between the outer ring 102 and the inner ring 103 are attached to both ends of the outer ring 102 in the axial direction. .

The outer ring spacer 104 has a substantially T-shaped cross section. Specifically, the outer ring spacer 104 includes an inner diameter side protruding portion 104a that is a T-shaped vertical line portion and a cylindrical portion 104b that is a T-shaped horizontal line portion. The inner peripheral surface of the inner protrusion 104a and the outer peripheral surface of the inner ring spacer 105 are opposed to each other with a radial clearance δ1. The outer ring spacer 104 is provided with a nozzle hole 115 for discharging the compressed air A for cooling toward the outer peripheral surface of the inner ring spacer 105. The outlet 115a of the nozzle hole 115 is open to the inner peripheral surface of the inner diameter side protruding portion 104a. The number of nozzle holes 115 is three, for example. The nozzle holes 115 are arranged at equal intervals in the circumferential direction. Although not shown, each nozzle hole 115 is inclined forward in the rotational direction D1 of the inner ring spacer 105 as in the first and second application examples.

An introduction groove 116 is formed on the outer peripheral surface of the outer ring spacer 104. The introduction groove 116 introduces the compressed air A from the outside of the bearing device J into each nozzle hole 115. Further, a discharge port 117 for compressed air A discharged from the nozzle hole 115 is provided on the end surface in the axial direction of the outer ring spacer 104. The discharge port 117 has the same notch shape as the first and second application examples. Each discharge port 117 is inclined forward in the rotation direction D <b> 1 of the inner ring spacer 105, similarly to the nozzle hole 115.

The inner ring spacer 105 has obstacle walls 153 projecting outward at both ends in the axial direction. The obstacle wall 153 of the third application example has a tapered shape in which the amount of protrusion toward the outer diameter side gradually increases toward the rolling bearing 101 in the axial direction. The inner ring spacer 105 of the third application example is divided in the axial direction in order to allow the outer ring spacer 104 to be assembled, that is, to prevent interference between the inner periphery of the outer ring spacer 104 and the obstacle wall 153. It consists of two inner ring spacers.

As shown in FIG. 19, the outer diameter end of the obstacle wall 153 faces the inner peripheral surface of the outer ring spacer 104 with a slight radial gap δ3. Further, the end face of the obstacle wall 153 faces the axially inner seal member 151 via a slight axial gap δ4. Thereby, the labyrinth seal portion 55 having a labyrinth seal effect is formed by the seal member 151 and the obstacle wall 153. The bearing internal space S1 and the spacer space S2 communicate with each other through the labyrinth seal portion 55.

In the bearing device J of the third application example, during operation, compressed air A for cooling is sent from a compressed air supply device provided outside the bearing device J, and the inner ring spacer 105 from the nozzle hole 115 of the outer ring spacer 104. It is supplied toward the outer peripheral surface of the. The compressed air A collides with the inner ring spacer 105 and then flows to both axial sides along the outer peripheral surface of the inner ring spacer 105. The compressed air A is further guided to the outer diameter side along the tapered outer diameter surface of the obstacle wall 153 of the inner ring spacer 105, and is discharged from the exhaust port 117 of the outer ring spacer 104.

In addition to guiding the compressed air A to the outer diameter side by the obstacle wall 153, the exhaust port 117 is inclined forward in the rotational direction D1 of the inner ring spacer 105 in the same manner as the nozzle hole 115. The flow of the compressed air A and the discharge of the compressed air A from the spacer space S2 become smooth. While the compressed air A passes through the spacer space S2, the bearing device J and the main shaft 107 supported by the bearing device J are deprived of heat. Thereby, the bearing device J and the main shaft 107 are efficiently cooled.

Since the obstacle walls 153 are provided at both axial ends of the inner ring spacer 105, the compressed air A is prevented from flowing into the bearing internal space S1. In particular, in the third application example, since the labyrinth seal portion 55 is provided between the bearing inner space S1 and the spacer space S2, the inflow of the compressed air A into the bearing inner space S1 is more effectively prevented. The Furthermore, since the compressed air A flows smoothly in the spacer space S2, the internal pressure of the spacer space S2 is lower than the internal pressure of the bearing internal space S1, and the compressed air A hardly flows into the bearing internal space S1. From these things, it can suppress that compressed air A flows in into bearing internal space S1, and it is prevented that the grease enclosed with bearing internal space S1 is excluded by compressed air A. Therefore, a good lubrication state can be maintained.

In the above first to third application examples, the inner ring rotation type rolling bearing 101 has been described, but the present invention can also be applied to an outer ring rotation type rolling bearing. In that case, a shaft (not shown) fitted to the inner circumference of the inner ring 103 constitutes a fixing member, and a roller (not shown) fitted to the outer circumference of the outer ring 2 constitutes a rotating member.

The application examples of the present invention shown in FIGS. 12 to 19 include the following modes 1 to 10.

[Aspect 1]
In the cooling structure for a bearing device according to aspect 1 of the present invention, a fixed side spacer and a rotary side spacer are respectively provided adjacent to a fixed side raceway and a rotary side raceway facing the inside and outside of the rolling bearing, The side race ring and the fixed side spacer are installed on a fixed member of the fixed member and the rotary member, and the rotary side race ring and the rotary side spacer are installed on the rotary member of the fixed member and the rotary member. A cooling structure for a bearing device,
The fixed side spacer is provided with a nozzle hole for discharging compressed air toward a circumferential surface facing the fixed side spacer in the rotating side spacer,
The outlet of the nozzle hole opens in a circumferential surface facing the rotating side spacer in the fixed side spacer,
An exhaust port for compressed air discharged from the nozzle hole is provided on the axial end face of the fixed spacer,
The nozzle hole is inclined forward in the rotation direction of the rotation side spacer, and the exhaust port is inclined forward in the rotation direction of the rotation side spacer.

According to this aspect 1, compressed air for cooling is discharged from the nozzle hole of the fixed side spacer toward the peripheral surface of the rotary side spacer. Since the nozzle hole is inclined forward in the rotation direction of the rotary spacer, the compressed air discharged from the nozzle hole flows in the axial direction while turning along the peripheral surface of the rotary spacer, and rotates during this period. The side spacer is cooled. Since the compressed air swirls, the time during which the compressed air is in contact with the peripheral surface of the rotating spacer is longer than when the compressed air flows straight in the axial direction. Therefore, the rotating side spacer can be efficiently cooled.

Compressed air that has passed through the circumferential surface of the rotating spacer is discharged to the outside through an exhaust port provided on the axial end surface of the fixed spacer and the inside of the rolling bearing. Since the exhaust port is also inclined forward in the rotational direction of the rotating side spacer, the compressed air that is a swirling flow is smoothly discharged from the exhaust port. Thereby, the amount of compressed air passing through the inside of the rolling bearing can be reduced. As a result, it is possible to eliminate or reduce adverse effects caused by a large amount of compressed air flowing inside the rolling bearing.

Specifically, when the rolling bearing is lubricated with air oil or oil mist, it is possible to prevent obstructing the smooth supply and exhaust of air oil. In addition, it is possible to suppress noise caused by collision of compressed air with a film of an air curtain-like air flow generated near the shaft end of the rolling bearing or a rotating rolling element. In addition, when the rolling bearing is lubricated with grease, it is possible to prevent compressed air from discharging grease inside the bearing.

[Aspect 2]
In the aspect 1, the nozzle hole and the exhaust port may be provided in a plurality, the number of both may be the same, and the nozzle hole and the exhaust port may be provided at equal intervals in the circumferential direction. In this case, the rotation side spacer can be evenly cooled in the circumferential direction by the compressed air discharged from the nozzle hole. In addition, the compressed air that has passed through the peripheral surface of the rotary spacer is evenly discharged from each exhaust port. For this reason, discharge of compressed air is performed smoothly.

[Aspect 3]
In the aspect 2, the circumferential distance from the outlet of any one of the nozzle holes to the exhaust port positioned in front of the nozzle hole in the rotation direction of the rotary spacer is arbitrary. It may be longer than the circumferential distance from one exhaust port to the outlet of the nozzle hole located on the front side in the rotation direction of the rotary spacer with respect to the exhaust port. With such a positional relationship between the nozzle hole and the exhaust port, the time during which the compressed air is in contact with the peripheral surface of the rotating spacer is long, and the cooling effect is high.

[Aspect 4]
In aspect 1, when the rolling bearing is lubricated by grease sealed inside the bearing between the fixed side raceway and the rotation side raceway, the rolling bearing is adjacent to the fixed side raceway in the rotary side spacer. An obstacle wall that protrudes toward the fixed spacer and prevents compressed air discharged from the nozzle hole from flowing into the bearing may be provided at the axial end. When the obstacle wall is provided, the compressed air is prevented from flowing into the bearing of the rolling bearing. For this reason, the grease sealed in the bearing is prevented from being removed by the compressed air, and a good lubricating state can be maintained.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Outer ring 3 ... Inner ring 4 ... Outer ring spacer 5 ... Inner ring spacer 6 ... Housing 7 ... Main shaft 10 ... Supply port 15 ... Obstacle wall 16, 17 ... Minute clearance 20 ... Exhaust port 21 ... Axial clearance DESCRIPTION OF SYMBOLS 23 ... Tapered part 30 ... Bearing space 30, 31 ... Seal material A ... Compressed air J ... Bearing apparatus LS ... 1st labyrinth seal

Claims (7)

1. An outer ring spacer and an inner ring spacer are respectively interposed between outer rings and inner rings of a plurality of rolling bearings arranged in the axial direction, the outer ring and the outer ring spacer are installed in a housing, and the inner ring and the inner ring spacer are arranged on a main shaft. A cooling structure of a bearing device that is fitted and lubricated by grease sealed in a bearing space between the outer ring and the inner ring,
   A supply port for supplying compressed air for cooling toward the outer peripheral surface of the inner ring spacer is provided on the inner peripheral surface of the outer ring spacer,
   An exhaust port for compressed air supplied from the supply port is provided on the axial end surface of the outer ring spacer,
   At both ends in the axial direction of the inner ring spacer, there are provided obstacle walls that prevent the compressed air supplied from the supply port from flowing out to the outer diameter side from flowing into the bearing space.
   A bearing device constituting a first labyrinth seal in which a part of the obstacle wall faces the outer ring spacer via a minute gap and obstructs a smooth flow of compressed air from the supply port to the exhaust port. Cooling structure.
2. 2. The bearing device cooling structure according to claim 1, wherein a plurality of portions of the obstacle wall are opposed to the outer ring spacer with a minute gap therebetween to constitute the first labyrinth seal. Cooling structure.
3. The cooling structure for a bearing device according to claim 1 or 2, wherein the rolling bearing has a seal material that seals the bearing space at an axial end of the outer ring,
   The end face of the obstacle wall is arranged to face the seal material in the axial direction,
   The bearing structure cooling structure which comprises the 2nd labyrinth seal which inhibits that the said compressed air flows in into the said bearing space with the said sealing material and the said obstruction wall.
4. 4. The cooling structure for a bearing device according to claim 1, wherein the gap is positioned on an inner side in an axial direction than the exhaust port,
   A cooling structure for a bearing device in which an axial portion between the gap and the exhaust port on the inner peripheral surface of the outer ring spacer has an inner diameter that gradually increases toward the exhaust port.
5. 5. The cooling structure for a bearing device according to claim 1, wherein the supply port is provided to be inclined forward in the rotational direction of the inner ring, and the exhaust port is provided between the outer rings. A cooling structure for a bearing device provided to be inclined forward in the rotational direction of the seat.
6. The cooling structure for a bearing device according to claim 5, wherein a plurality of the supply ports and the exhaust ports are provided in the same number,
   A cooling structure for a bearing device in which the nozzle hole and the exhaust port are provided at equal intervals in the circumferential direction.
7. The cooling structure for a bearing device according to claim 6, wherein a circumferential distance from an arbitrary supply port to the exhaust port located on the front side in the rotation direction of the inner ring spacer with respect to the supply port is A cooling structure for a bearing device that is longer than a distance in a circumferential direction from an exhaust port to the supply port located on the front side in the rotation direction of the inner ring spacer.
   

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