JP2024043034A - bearing device - Google Patents

Abstract

To provide a bearing device capable of effectively cooling a cylindrical roller bearing without interrupting the lubrication of an angular ball bearing on the cylindrical roller bearing side.SOLUTION: The bearing device includes a plurality of bearings consisting of cylindrical roller bearings 2 and combined angular ball bearings 3 arranged side by side in an axial direction, and a cooling mechanism 4 for cooling each of the bearings, and further includes air supply amount adjusting means 20 for adjusting a supply amount of compressed air flowing into one angular ball bearing 3A adjacent to the cylindrical roller bearing 2, out of the combined angular ball bearing 3. In the air supply amount adjusting means 20, a relation of I>II>III is established among an outer diameter position I of one end face 13a adjacent to an inward spacer 6, of an inner ring 13 of one angular ball bearing 3A, an outer diameter position II of one end face 12a adjacent to the inward spacer 6, of an inner ring 12 of the cylindrical roller bearing 2, and a radial position III of an inner peripheral face 5a of an air-cooling spacer 5.SELECTED DRAWING: Figure 4

Description

The present invention relates to a bearing device, and relates to a technology applied to a cooling structure for a bearing in a main spindle device composed of a cylindrical roller bearing and an angular contact ball bearing used for supporting the main spindle of a machine tool, industrial machinery, and other high-speed rotations. .

Among machine tools, angular contact ball bearings are widely used as support bearings that operate at high speeds, including the main spindle of machining centers. In the spindle device, a cylindrical roller bearing may be disposed on the tool tip side in order to suppress the spindle displacement to a small level in response to an external load from the tip of the spindle during machining, or to cope with high-load machining. These main shafts are often used with oil lubrication, such as air-oil lubrication or ormist lubrication, which constantly supplies new oil to the bearings and maintains a stable lubrication state over a long period of time. Both lubrication methods use compressed air to supply a small amount of lubricating oil into the bearing.

At the tip of the main shaft, a cylindrical roller bearing, a spacer with an air oil nozzle that supplies air oil to the cylindrical roller bearing, and an angular contact ball bearing for axial loads are arranged in this order, and the inner diameter and outer diameter are usually the same.
Among bearings of the same size, line contact cylindrical roller bearings generate more heat during high-speed operation than point contact angular contact ball bearings. Furthermore, in order to meet the demands of high-speed spindles, angular contact ball bearings often use ceramic balls, but ceramic rollers in cylindrical roller bearings are expensive, and in practice, bearing steel rollers are the mainstream. From this point of view, the heat generation of cylindrical roller bearings becomes an issue in increasing the speed of the main shaft.

In addition, in the main shaft, the outer ring side on the housing side has excellent heat dissipation, and the temperature of the inner ring side that fits into the shaft side becomes high. Due to this temperature difference between the inner ring and outer ring, the preload at the time of assembly becomes even higher during operation. , Continuous operation at high speeds may lead to abnormal heat generation of the main shaft. In order to suppress such a temperature difference between the inner and outer rings, there is a cooling structure for a bearing device that uses an air cooling spacer between back-to-back alignments of angular contact ball bearings (Patent Document 1).

In the conventional main shaft shown in FIG. 9, air oil is supplied to the cylindrical roller bearing 50 from an outer ring spacer 52 provided between the cylindrical roller bearing 50 and the axial load angular contact ball bearing 51. Also, air oil is supplied to the angular ball bearing 51 from the spacer 53 of the axial load angular ball bearing 51 which is aligned back to back.
In air-oil lubrication, one shot is approximately 0.01 to 0.03cc of oil, and the amount of oil inside the bearing is adjusted by adjusting the oil supply interval. In addition, compressed air is supplied at a rate of about 20 to 40 NL/min to transport this lubricating oil inside the bearing.

In the technology of Patent Document 1, for example, if the inner diameter of the bearing is 70 mm, compressed air is supplied from the adjacent outer ring spacer side to the inner ring spacer side at 100 to 300 NL/min to cool the inner ring spacer side and Cool the inner rings of the angular contact ball bearings on both sides. This suppresses the temperature difference between the inner and outer wheels and suppresses the increase in preload during operation, thereby enabling high-speed operation and achieving a higher preload state from the beginning.

Patent No. 6144024

When cooling cylindrical roller bearings, an extremely large amount of compressed air is supplied, 3 to 10 times the amount of air used for air-oil lubrication. In this case, when a large amount of compressed air flows into the angular contact ball bearing on the cylindrical roller bearing side, the air oil supplied from the spacer located on the back-to-back mating surface of the angular contact ball bearing flows into the angular contact ball bearing located on the cylindrical roller bearing side. This prevents smooth lubrication.
It is necessary to effectively cool the cylindrical roller bearing without interfering with the air-oil lubrication of the angular contact ball bearing on the cylindrical roller bearing side.

An object of the present invention is to provide a bearing device that can effectively cool a cylindrical roller bearing without interfering with the lubrication of the angular contact ball bearing on the cylindrical roller bearing side.

The bearing device of the present invention is a bearing device including a plurality of cylindrical roller bearings and a combination angular ball bearing arranged in the axial direction, and a cooling mechanism that cools each of these bearings, the bearing device comprising:
Of the combination angular contact ball bearings, an air supply amount adjusting means is provided for adjusting the amount of compressed air flowing into one angular contact ball bearing adjacent to the cylindrical roller bearing.
Adjusting the supply amount of compressed air means adjusting the supply amount of compressed air flowing into one angular ball bearing relative to the supply amount of compressed air supplied to the cylindrical roller bearing.

According to this configuration, the air supply amount adjusting means is provided to adjust the amount of compressed air supplied to one of the angular ball bearings adjacent to the cylindrical roller bearing among the combination angular ball bearings. This prevents the amount of compressed air flowing into one of the angular contact ball bearings from becoming too large. It passes smoothly through the inside of the one angular contact ball bearing. Therefore, the cylindrical roller bearing can be effectively cooled without interfering with the lubrication of the angular ball bearing on the cylindrical roller side.

An inner spacer is provided between the inner member of the cylindrical roller bearing and the inner member of the one angular contact ball bearing, and the cooling mechanism is located radially outward of the inner spacer, and It has an air cooling spacer equipped with a nozzle that discharges compressed air toward the outer peripheral surface of the inner spacer,
The air supply amount adjusting means is configured to adjust an outer diameter position I of one end surface adjacent to the inner spacer in the inner member of the one angular contact ball bearing and the inner diameter position I of the inner member of the cylindrical roller bearing. The outer diameter position II of one end surface adjacent to the spacer and the radial position III of the inner peripheral surface of the air cooling spacer may have a relationship of I>II>III.
Since the outer diameter position I, the outer diameter position II, and the radial position III are in the relationship I>II>III, the compressed air coming out of the discharge port of the nozzle of the air cooling spacer can be urged toward the cylindrical roller bearing side. Can be done.

The air supply amount adjusting means has a stepped structure in which an inner circumferential surface portion of the air cooling spacer on the cylindrical roller bearing side has a larger diameter than an inner circumferential surface portion on the one angular contact ball bearing side. It may be configured as follows. In this case, the compressed air coming out of the discharge port of the nozzle is blocked by the upstream step, so that the compressed air can be more reliably urged toward the cylindrical roller bearing side.

An exhaust path is provided between the cylindrical roller bearing and the air-cooled spacer for exhausting air used for cooling the inner spacer and the cylindrical roller bearing, and is used for cooling the combination angular contact ball bearing. The exhaust port for exhausting air and the exhaust path may be provided in a non-communicating state. By arranging the exhaust port and the exhaust path separately without communicating with each other in this way, the air used for cooling each bearing can be smoothly exhausted and the cooling effect can be improved.

The system may include a housing in which the bearings and the air-cooled spacer are mounted, and exhaust holes that communicate with exhaust ports on both axial sides of the air-cooled spacer may be formed in the housing, with the exhaust hole on the angular ball bearing side being larger in diameter than the exhaust hole on the cylindrical roller bearing side. In this case, the air used to cool each bearing can be exhausted more smoothly, further improving the cooling effect.

An inner spacer is provided between the inner members of the combination angular contact ball bearing, and the cooling mechanism is located radially outward of the inner spacer and directs compressed air toward the outer peripheral surface of the inner spacer. It has an air cooling spacer equipped with a nozzle that discharges
The air supply amount adjusting means may set the amount of air supplied to the air cooling spacer between the cylindrical roller bearing and the angular contact ball bearing to be equal to or less than the amount of air supplied to the air cooling spacer between the combined angular contact ball bearings. In this way, adding an air-cooled spacer improves the cooling effect, and by directly adjusting the air supply itself, the cylindrical roller bearing can be made even better without interfering with the air-oil lubrication of the angular contact ball bearing on the cylindrical roller side. It becomes possible to cool the bearing device effectively, and further increase the speed of the bearing device.

The bearing device of the present invention includes an air supply amount adjusting means for adjusting the amount of compressed air flowing into one angular ball bearing adjacent to the cylindrical roller bearing. This prevents the compressed air flowing into one of the angular contact ball bearings from becoming too large, and allows the lubricating oil supplied from between the combined angular contact ball bearings to flow into the other angular contact ball bearing without resisting the compressed air. Pass through the interior smoothly. Therefore, the cylindrical roller bearing can be effectively cooled without interfering with the lubrication of the angular ball bearing on the cylindrical roller side.

FIG. 1 is a longitudinal cross-sectional view of a bearing device according to a first embodiment of the present invention. 2 is a sectional view taken along the line II-II in FIG. 1. FIG. It is a figure explaining the flow of cooling air. It is a figure explaining the air supply amount adjustment means of a bearing device. It is a figure further explaining the same air supply amount adjustment means. FIG. 3 is an enlarged cross-sectional view of main parts of a bearing device according to a second embodiment of the present invention. FIG. 7 is an enlarged sectional view of main parts of a bearing device according to a third embodiment of the present invention. FIG. 7 is a longitudinal cross-sectional view of a bearing device according to a fourth embodiment of the present invention. FIG. 8B is a sectional view taken along line VIIIB-VIIIB of FIG. 8A. FIG. 2 is a vertical cross-sectional view of a conventional spindle device.

[First embodiment]
A bearing device according to an embodiment of the present invention will be described with reference to FIGS.
The bearing device according to the embodiment is applied to, for example, a spindle device of a machine tool, etc. However, the application of the bearing device is not limited to only the spindle device of a machine tool.
1, the bearing device 1 includes a plurality of rolling bearings 2, 3, each of which includes a cylindrical roller bearing 2 and a duplex angular contact ball bearing 3, arranged in an axial direction, and a cooling mechanism 4 for cooling each of the rolling bearings 2, 3. In this specification, the rolling bearings may be simply referred to as bearings.

From the front side of the main shaft 14 toward the rear side in the axial direction, the cylindrical roller bearing 2, the air cooling spacer 5 and the inner spacer 6 of the cooling mechanism 4, one angular ball bearing 3A in the combination angular ball bearing 3, and the outer spacer The seat 7, the inner spacer 8, and the other angular ball bearing 3B are arranged. Outer rings 9, 10, air-cooled spacers 5, and outer spacers 7, which are outer members of each bearing, are installed in the housing 11, inner rings 12, 13, which are inner members of each bearing, and each inner spacer 6, 8 is fitted onto the main shaft 14 which is a rotating shaft.

As the combination angular contact ball bearing 3, two angular contact ball bearings 3A and 3B are installed in a back-to-back combination, and a counterbore is provided on the opposite side of the contact angle on the outer diameter surface of the inner ring and the inner diameter surface of the outer ring. The counterbore of the outer ring 10 is formed in an inclined surface whose diameter becomes smaller as it goes from the outer ring end face side toward the raceway surface side. A plurality of rolling elements 15 are interposed between the raceway surfaces of the inner and outer rings 13 and 10, and these rolling elements 15 are held by a retainer 16 at equal intervals around the circumference. The cage 16 has an outer ring-guided ring shape. The bearing clearance is adjusted, for example, by one or both of the width difference between the air cooling spacer 5 and the inner spacer 6, and the width difference between the outer spacer 7 and the inner spacer 8. Each bearing is lubricated with air-oil lubrication suitable for high-speed operation.

<Cooling mechanism>
FIG. 2 is a sectional view taken along line II-II in FIG. As shown in FIG. 1, the cooling mechanism 4 has a ring-shaped air cooling spacer 5 in which a nozzle 17 is provided. The air cooling spacer 5 is located radially outward of the inner spacer 6 and discharges compressed air from a nozzle 17 toward the outer peripheral surface of the inner spacer 6. As shown in FIG. 2, a plurality of nozzles 17 (three in this example) are arranged at equal intervals around the circumference, and the air discharge direction of these nozzles 17 is inclined forward in the rotational direction L1 of the main shaft 14. .

Each nozzle 17 is linear, and is located at a position offset from an arbitrary radial straight line L2 in a cross section perpendicular to the axis of the air cooling spacer 5 in a direction perpendicular to this straight line L2. By offsetting the nozzle 17, the discharged air acts as a swirling flow in the rotational direction L1 of the main shaft 14, thereby improving the cooling effect. The offset amount of the nozzle 17 is appropriately set based on tests, simulations, or the like.

An introduction groove 18 for introducing compressed air, which is cooling air, is provided on the outer peripheral surface of the air cooling spacer 5. As shown in FIG. 3, the introduction groove 18 is provided in the axially intermediate portion of the outer peripheral surface of the air cooling spacer 5, and is formed in an arcuate shape communicating with each nozzle 17 as shown in FIG. The introduction groove 18 is provided on the outer circumferential surface of the air-cooling spacer 5 over an angular range α1 that occupies most of the circumferential direction except for a circumferential position P1 where an air-oil supply hole 19, which will be described later, is provided. The compressed air introduction path is independent from the air oil for bearing lubrication.

As shown in FIG. 1, the housing 11 is provided with a cooling air supply hole 19, and the cooling air supply hole 19 is configured to communicate with the introduction groove 18 (FIG. 3). A supply device (not shown) that supplies compressed air to the cooling air supply holes 19 is connected to the outside of the housing 11 through piping.

As shown in FIG. 3, when the cooling air flows into the angular contact ball bearing 3A, there is a possibility that the air oil of the angular contact ball bearing 3A may be obstructed from passing through the angular contact ball bearing 3A. It is necessary to encourage the compressed air to be exhausted to the cylindrical roller bearing 2 side.
Therefore, the bearing device 1 is equipped with an air supply amount adjusting means for adjusting the amount of compressed air flowing into one angular contact ball bearing 3A adjacent to the cylindrical roller bearing 2 among the combination angular contact ball bearings 3. The supply amount of compressed air refers to the volume of compressed air supplied per unit time.

<About air supply amount adjustment means>
As shown in FIG. 4, the air supply amount adjusting means 20 adjusts the outer diameter position I of one end surface 13a of the inner member 13 of one angular contact ball bearing 3A adjacent to the inner spacer 6 and the cylindrical roller bearing 2. In the inner ring 12, the outer diameter position II of one end surface 12a adjacent to the inner spacer 6 and the radial position III of the inner peripheral surface 5a of the air cooling spacer 5 have a relationship of I>II>III. The detailed dimensions of radial positions I, II and radial position III are determined by testing and/or simulation. Based on the above relationship, the amount of compressed air supplied to one of the angular ball bearings 3A is adjusted to be lower than the amount of compressed air supplied to the cylindrical roller bearing 2. Therefore, the inner spacer 6 between the cylindrical roller bearing 2 and the angular contact ball bearing 3A is effectively cooled without interfering with the lubrication supply to the angular contact ball bearings 3A, 3B (FIG. 1), and the inner spacer 6 between the cylindrical roller bearing 2 and the angular contact ball bearing 3A is indirectly cooled. can cool the inner ring 12 of.

As shown in FIG. 5, the radial clearance a3 between the outer diameter surface of the inner spacer 6 and the inner diameter surface 5a of the air cooling spacer 5 at the nozzle position is 0.7 mm or more, and the nozzle hole diameter b The relationship is set to 1/2 or less. By setting the radial gap a3 to 1/2 or less of the nozzle hole diameter b, the pressure at the discharge port of the nozzle 17 is increased, and rapid expansion of air is suppressed, thereby reducing jet noise. If the radial clearance a3 is smaller than 0.7 mm, the exhaust area near the nozzle outlet is not secured, the amount of cooling air decreases, and the cooling effect deteriorates.

<Lubrication structure>
1, the air cooling spacer 5 and the outer spacer 7 have lubrication nozzles 21 that supply air oil into the corresponding bearings. In the air cooling spacer 5, an air oil supply hole 22 is formed to a predetermined depth radially inward from the outer circumferential surface of the air cooling spacer 5, and communicates with the lubrication nozzle 21 near the bottom of the air oil supply hole 22. The lubrication nozzle 21 extends in the axial direction from the base end side to the tip end side, and is formed so that air oil is supplied between the outer circumferential surface of the inner ring of the cylindrical roller bearing 2 and the inner circumferential surface of the cage.

In the outer spacer 7, an air oil supply hole 22 is formed that is formed from the outer peripheral surface of the outer spacer 7 to a predetermined depth radially inward, and the air oil supply hole 22 communicates with a lubrication nozzle 21 that extends on both axial sides near the bottom of the hole. These lubrication nozzles 21 are formed as through holes with an inclination angle so that they reach the inner diameter side as they move from the base end side toward the target angular ball bearing side. In addition, the lubrication nozzles 21 are formed so that air oil is supplied between the outer peripheral surface of the inner ring of the target angular ball bearing 3A, 3B and the inner peripheral surface of the cage.

A bearing box supply hole 23 for air oil is provided in the housing 11, and each air oil supply hole 22 communicates with this bearing box supply hole 23. An air-oil supply device (not shown) that supplies air-oil to the bearing box supply hole 23 is connected to the outside of the housing 11 by piping. During operation, the air oil supplied from the air oil supply device is sequentially discharged from the bearing box supply hole 23, each air oil supply hole 22, and the lubrication nozzle 21 to the target bearing.

<Exhaust structure>
The bearing device 1 is provided with an air-oil exhaust passage 24 that exhausts air used for cooling and air oil used for lubrication. The air oil exhaust passage 24 includes exhaust ports 25 and 26 formed on both sides of the air cooling spacer 5 in the axial direction, as shown in FIG. It has exhaust ports 27 and 28 and exhaust holes 29a and 29b formed in the housing 11.
Among the exhaust ports 25 and 26 on both sides of the air cooling spacer 5 in the axial direction shown in FIG. The air used for cooling the roller bearing 2 and the air oil used for lubricating the cylindrical roller bearing 2 are exhausted. Further, the air and the air oil are also exhausted from a labyrinth portion 32 between an outer ring holder 30 and an inner ring holder 31 provided at the front end of the housing 11 shown in FIG.

Among the exhaust ports 25 and 26 on both axial sides of the air-cooled spacer 5 in FIG. The exhaust ports 27 and 28 formed on both sides are the inner spacer 8 provided between the inner rings 13 and 13 of the combined angular contact ball bearing 3, the air used for cooling the combined angular contact ball bearing 3, and The air oil used to lubricate the combination angular contact ball bearing 3 is exhausted.

The exhaust ports 26, 27, and 28 used for cooling the combination angular contact ball bearing 3 and the exhaust port (exhaust path) 25 between the cylindrical roller bearing 2 and the air cooling spacer 5 are in a non-communicating state, that is, in a separate state. It is provided to serve as an exhaust outlet. Specifically, as shown in FIG. 5, among the exhaust holes 29a and 29b formed in the housing 11, one exhaust hole 29a communicates with the exhaust port (exhaust path) 25, and the other exhaust hole 29b communicates with the exhaust hole 29b. It communicates with exhaust ports 26, 27, and 28 used for cooling the angular ball bearings 3A and 3B (FIG. 1). In addition, in the housing 11, among the exhaust holes 29a and 29b communicating with the exhaust ports 25 and 26 on both sides of the air cooling spacer 5 in the axial direction, the exhaust hole 29b on the angular ball bearing 3A side is the exhaust hole 29a on the cylindrical roller bearing 2 side. It is provided with a larger diameter than the

<Effect>
According to the bearing device 1 of FIG. 1 described above, the air supply amount adjustment means 20 adjusts the amount of compressed air supplied to the one angular contact ball bearing 3A adjacent to the cylindrical roller bearing 2 among the combination angular contact ball bearings 3. (Figure 4). Specifically, as shown in FIG. 4, the air supply amount adjusting means 20 adjusts the outer diameter position I of one end surface 13a adjacent to the inner spacer 6 of the inner ring 13 of one angular contact ball bearing 3A and the cylindrical roller. In the inner ring 12 of the bearing 2, the outer diameter position II of one end surface 12a adjacent to the inner spacer 6 and the radial position III of the inner peripheral surface 5a of the air cooling spacer 5 have a relationship of I>II>III. be.

Therefore, the compressed air coming out of the discharge port of the nozzle 17 of the air-cooled spacer 5 is smoothly urged toward the cylindrical roller bearing 2 side, while being directed toward the angular contact ball bearing 3A side at the outer diameter position I. It is somewhat obstructed by the end surface 13a, and the amount of compressed air supplied is appropriately reduced. Therefore, the compressed air flowing into the one angular contact ball bearing 3A is prevented from becoming excessive, and the air oil supplied from between the combination angular contact ball bearings is not only inside the other angular contact ball bearing, but also inside the one angular contact ball bearing 3A. It passes smoothly through the inside of the ball bearing 3A.

Therefore, the cylindrical roller bearing 2 can be effectively cooled without interfering with the lubrication of the angular ball bearing 3A on the cylindrical roller side. This makes it possible to operate at high speeds by suppressing the temperature difference between the inner and outer rings during continuous operation at high speeds and suppressing the increase in preload during operation. Air and air oil are also exhausted from the labyrinth part 32 between the outer ring holder 30 and the inner ring holder 31 provided at the front end of the housing 11, as shown in FIG. etc. can be prevented from entering.

The exhaust ports 26, 27, 28 used for cooling the combined angular ball bearing 3 and the exhaust port (exhaust path) 25 between the cylindrical roller bearing 2 and the air-cooled spacer 5 are provided as separate exhaust outlets. By making the exhaust ports 26, 27, 28 and the exhaust path 25 separate and not connected to each other in this way, the air used for cooling each bearing can be smoothly exhausted, improving the cooling effect. In the housing 11, of the exhaust holes 29a, 29b that communicate with the exhaust ports 25, 26 on both axial sides of the air-cooled spacer 5, the exhaust hole 29b on the angular ball bearing side is provided with a larger diameter than the exhaust hole 29a on the cylindrical roller bearing side, so that the air used for cooling each bearing can be more smoothly exhausted, further improving the cooling effect.

<About other embodiments>
In the following description, parts corresponding to those previously described in each embodiment are given the same reference numerals, and redundant description will be omitted. When only a part of the configuration is described, other parts of the configuration are the same as those of the previously described embodiment unless otherwise specified. Identical configurations produce the same effects. It is not only possible to combine the parts specifically described in each embodiment, but also to partially combine the embodiments, as long as the combination does not cause any problems.

[Second embodiment: Figure 6 (air cooling spacer, stepped)]
As shown in FIG. 6, the air supply amount adjusting means 20 is arranged so that the first inner circumferential surface portion 5aa on the cylindrical roller bearing side of the inner circumferential surface 5a of the air cooling spacer 5 is the same as the second inner circumferential surface portion 5aa on the angular ball bearing side. It may be stepped with a diameter larger than that of the inner circumferential surface portion 5ab. In this case, the compressed air coming out of the discharge port of the nozzle 17 is somewhat blocked by the step on the upstream side, so that the compressed air can be more reliably urged toward the cylindrical roller bearing side.

In this configuration, the nozzle position of the air cooling spacer 5 is located at the first inner circumferential surface portion 5aa. Further, the radial clearance a3 between the outer diameter surface of the inner spacer 6 and the first inner circumferential surface portion 5aa of the air cooling spacer 5 is 0.7 mm or more and 1/2 or less of the nozzle hole diameter b. The relationship is set as follows. Further, the outer diameter surface of the inner spacer 6 and the second inner circumferential surface portion 5ab of the air cooling spacer 5 must not interfere with each other due to temperature rise and expansion due to centrifugal force during operation. As a result, the radial clearance a4 between the outer diameter surface of the inner spacer 6 and the second inner circumferential surface portion 5ab is practically set to 0.2 mm or more.

[Third embodiment: Fig. 7 (air cooling spacer, circumferential groove)]
As shown in FIG. 7, the air supply amount adjusting means 20 may have a configuration in which a circumferential groove 33 is provided in the widthwise center portion of the inner circumferential surface of the air cooling spacer 5. In this configuration, the first inner circumferential surface portion 5aa on the cylindrical roller bearing side of the air-cooled spacer 5 is set to have a larger diameter than the second inner circumferential surface portion 5ab on the one angular contact ball bearing side. has been done. The nozzle position of the air cooling spacer 5 is located at the central portion in the width direction. In this case, since the circumferential groove 33 is provided, the amount of compressed air supplied can be increased compared to the second embodiment described above, and the cooling effect can be further enhanced.

The radial clearance a3 between the outer diameter surface of the inner spacer 6 and the widthwise center portion of the inner circumferential surface of the air cooling spacer 5 is 0.7 mm or more and 1/2 or less of the nozzle hole diameter b. Set to relationship. Further, the outer diameter surface of the inner spacer 6 and the second inner peripheral surface portion 5ab of the air-cooled spacer 5 on the angular contact ball bearing side must not interfere with each other due to temperature rise and expansion due to centrifugal force during operation. As a result, the radial clearance a4 between the outer diameter surface of the inner spacer 6 and the second inner circumferential surface portion 5ab is practically set to 0.2 mm or more.

Furthermore, the radial clearance a5 between the outer diameter surface of the inner spacer 6 and the first inner peripheral surface portion 5aa of the air-cooled spacer 5 on the cylindrical roller bearing side is made larger than the radial clearance a4. Therefore, the radial position III of the widthwise central portion of the inner circumferential surface of the air cooling spacer 5>the radial position V of the first inner circumferential surface portion 5aa of the air cooling spacer 5>the second inner circumference of the air cooling spacer 5 The radial position of the peripheral surface portion 5ab is assumed to be IV. With such a radial position, the compressed air discharged from the discharge port of the nozzle 17 can be appropriately distributed to the cylindrical roller bearing side and the angular ball bearing side.

Also, the outer diameter position I of one end surface of the inner ring 13 of one angular contact ball bearing 3A adjacent to the inner spacer 6 and the outer diameter position I of one end surface of the inner ring 12 of the cylindrical roller bearing 2 adjacent to the inner spacer 6. The radial position II and the aforementioned radial positions III, V, and IV have a relationship of I>II>III>V>IV.

[Fourth embodiment: FIGS. 8A and 8B (air supply amount)]
FIG. 8B is a sectional view taken along the line VIIIB-VIIIB of FIG. 8A. As shown in FIGS. 8A and 8B, the cooling mechanism 4 includes, in addition to the air cooling spacer 5 described above (referred to as the "first air cooling spacer" for convenience), an inner spacer 8 between the combination angular contact ball bearings. The second air cooling spacer 5A may be provided with a nozzle 17 located radially outward of the inner spacer 8 and discharging compressed air toward the outer peripheral surface of the inner spacer 8.
In this case, the air supply amount adjusting means 20 adjusts the amount of air supplied to the first air cooling spacer 5 between the cylindrical roller bearing 2 and the angular contact ball bearing 3A to the amount of air supplied to the second air cooling spacer 5A between the combined angular contact ball bearings. The air supply amount shall be below. Each specific air supply amount is determined, for example, by testing and/or simulation. The air supply amount is adjusted, for example, by a supply device (not shown) that supplies compressed air or a flow control valve connected to the supply device via piping.

By adding the second air-cooled spacer 5A in this way, the cooling effect is improved, and by directly adjusting the air supply amount itself, the air-oil lubrication of the angular contact ball bearing 3A on the cylindrical roller side is not inhibited. It becomes possible to cool the cylindrical roller bearing 2 more effectively, and the speed of the bearing device 1 can be further increased.

The bearing device can also be applied to, for example, industrial machines, robots, conveyance machines, and the like.
The inner member of each bearing includes, for example, one in which the inner ring and the shaft are integrated, and one in which a gear is formed on the inner peripheral surface of the inner ring. The outer member of each bearing includes one in which the outer ring and the housing are integrated, and one in which a gear is formed on the outer circumferential surface of the outer ring. The term "integral" means that the bearing ring and the object are not formed by combining a plurality of elements, but are formed from a single material as a part or whole of a single object, for example, by forging, machining, etc.

<Reference proposal example>
Instead of the cylindrical roller bearing in the bearing device, it is also possible to apply various rolling bearings such as angular contact ball bearings, deep groove ball bearings, tapered roller bearings, and needle roller bearings. The bearing device in this case is described as follows.
A bearing device comprising a plurality of rolling bearings and a combination angular contact ball bearing arranged in the axial direction, and a cooling mechanism that cools each of these bearings,
A bearing device comprising an air supply amount adjusting means for adjusting the amount of compressed air flowing into one angular ball bearing adjacent to the rolling bearing among the combination angular ball bearings.

Although the embodiments of the present invention have been described above, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1...bearing device, 2...cylindrical roller bearing, 3...combined angular contact ball bearing, 3A, 3B...angular contact ball bearing, 4...cooling mechanism, 5, 5A...air cooling spacer, 5aa...first inner peripheral surface portion, 5ab...second inner peripheral surface portion, 6...inner spacer, 9, 10...outer ring (outer member), 12, 13...inner ring (inner member), 20...air supply amount adjustment means, 25, 26, 27, 28...exhaust port, 29a, 29b...exhaust hole

Claims (6)

A bearing device comprising a plurality of cylindrical roller bearings and a combination angular contact ball bearing arranged in the axial direction, and a cooling mechanism that cools each of these bearings,
A bearing device comprising an air supply amount adjusting means for adjusting the amount of compressed air flowing into one angular ball bearing adjacent to the cylindrical roller bearing among the combination angular ball bearings. The bearing device according to claim 1, further comprising an inner spacer between the inner member of the cylindrical roller bearing and the inner member of the one angular contact ball bearing, and the cooling mechanism It has an air cooling spacer that is located radially outward of the seat and is provided with a nozzle that discharges compressed air toward the outer peripheral surface of the inner spacer,
The air supply amount adjusting means is configured to adjust an outer diameter position I of one end surface adjacent to the inner spacer in the inner member of the one angular contact ball bearing and the inner diameter position I of the inner member of the cylindrical roller bearing. A bearing device in which an outer diameter position II of one end surface adjacent to a spacer and a radial position III of an inner peripheral surface of the air-cooled spacer have a relationship of I>II>III. 3. The bearing device according to claim 2, wherein the air supply amount adjusting means is arranged such that an inner circumferential surface portion of the inner circumferential surface of the air cooling spacer on the side of the cylindrical roller bearing has an inner circumferential surface portion on the side of the one angular contact ball bearing. A bearing device with a stepped structure that has a larger diameter than the face part. In the bearing device according to claim 2 or 3, an exhaust path is provided between the cylindrical roller bearing and the air cooling spacer for exhausting air used for cooling the inner spacer and the cylindrical roller bearing. A bearing device, wherein an exhaust port for exhausting air used for cooling the combination angular ball bearing and the exhaust path are provided in a non-communicating state. 5. The bearing device according to claim 4, further comprising a housing in which the plurality of bearings and the air cooling spacer are installed, and exhaust holes are formed in the housing that communicate with exhaust ports on both sides of the air cooling spacer in the axial direction. A bearing device in which the exhaust hole on the angular ball bearing side of these exhaust holes is provided with a larger diameter than the exhaust hole on the cylindrical roller bearing side. The bearing device according to any one of claims 2 to 5, wherein an inner spacer is provided between the inner members of the combination angular contact ball bearing, and the cooling mechanism is arranged in a radial direction of the inner spacer. An air cooling spacer is provided with a nozzle located outwardly and discharging compressed air toward the outer peripheral surface of the inner spacer,
In the bearing device, the air supply amount adjusting means makes the amount of air supplied to the air cooling spacer between the cylindrical roller bearing and the angular contact ball bearing equal to or less than the amount of air supplied to the air cooling spacer between the combined angular contact ball bearings.

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