JP2014062620A - Cooling structure for bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure that can efficiently cool a bearing device and a shaft supported by the bearing device, and excellently supply oil for lubrication to each roll bearing.SOLUTION: A bearing device J has three or more roll bearings 1 arranged side by side in an axial direction and also has outer ring spacers 4 and inner ring spacers 5, the spacers being each interposed between adjacent roll bearings 1. Each outer ring spacer 4 has at its axial end an oil supply port 21 for supplying a mixture 20 of air and oil to the roll bearings 1. A cooling air discharge port 11 for discharging cooling air 10 toward an outer peripheral surface of the inner ring spacer 5 is provided in an inner peripheral surface of each outer ring spacer 4. Cooling air 10 discharged from each cooling air discharge port 11 has its flow rate and pressure so related that cooling air 10 discharged from the cooling air discharge port 11 of the outer ring spacer 4 located on a downstream side in the flowing direction of the mixture 20 of air and oil does not flow backward against the flow of the mixture 20 of air and oil.

Description

  The present invention relates to a cooling structure for a bearing device used in a machine tool, an industrial machine, or the like, in which three or more rolling bearings lubricated by a mixture of air and oil are arranged side by side.

  In a spindle device of a machine tool, it is necessary to suppress the temperature rise of the device to be small in order to ensure machining accuracy. However, recent machine tools have a tendency to increase the speed in order to improve the processing efficiency, and the heat generated from the bearing supporting 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 rise in the temperature of the bearing due to heat generation results in an increase in preload, and we want to suppress it as much as possible in consideration of higher speed and higher accuracy of the spindle. As a structure that suppresses the temperature rise of the spindle device, there is a structure in which cooling air is sent to a space between the inner peripheral surface of the outer ring spacer and the outer peripheral surface of the inner ring spacer to cool the shaft and the bearing (for example, Patent Documents). 1).

JP 2000-161375 A

  Since the cooling structure using the cooling air has a high cooling effect, it can be expected to effectively suppress the temperature rise of the spindle device. However, when three or more rolling bearings are arranged in the axial direction and each rolling bearing is lubricated with air oil, it is necessary to consider the interrelationship between the air flow of air oil and the flow of cooling air. The same applies when the rolling bearing is lubricated by oil mist.

For example, as shown in FIG. 9, four rolling bearings 1A, 1B, 1C, 1D made of angular ball bearings are combined in parallel with the left two rolling bearings 1A, 1B and the two right rolling bearings 1C, 1D. In the bearing device J in which the two rolling bearings 1B and 1C at the center are arranged in combination with each other on the back, the supply / discharge paths of the air oil 20 and the cooling air 10 are generally as follows.
That is, the air oil 20 is supplied to the two center rolling bearings 1B and 1C from oil supply ports (not shown) provided at both axial ends of the central outer ring spacer 4M, as indicated by the broken arrows. At the same time, oil is supplied to the outer rolling bearings 1A and 1D from oil supply ports (not shown) provided in the outer ring spacers 4L and 4R on the left and right sides, respectively.
The cooling air 10 is discharged from the cooling air discharge port 11M provided in the central outer ring spacer 4M to the central outer ring spacer 4M and the inner ring spacer 5M, as shown by the solid line arrows. Are discharged from the cooling air discharge ports 11L and 11R provided in the outer ring spacers 4L and 4R to the left and right outer ring spacers 4L and 4R and the inner ring spacers 5L and 5R.
The air of the air oil 20 after supplying the lubricating oil to the rolling bearings 1A, 1B, 1C, 1D and the cooling air 10 after cooling the bearing device J and the main shaft 7 are both outer ring spacers 4L, 4M. , 4N are discharged to the outside of the spindle device from exhaust ports (not shown) provided at both axial ends.

  In the case of the bearing device J in FIG. 9, the air oil 20 injected from the oil supply port of the central outer ring spacer 4M is the cooling air 10 discharged from the cooling air discharge port 11M of the central outer ring spacer 4M. Flows in the same direction. However, a part of the cooling air 10 discharged from the cooling air discharge ports 11L and 11R of the outer ring spacers 4L and 4R on the left and right sides also flows to the center rolling bearings 1B and 1C. The cooling air 10 discharged from the cooling air discharge ports 11L, 11R of the left and right outer ring spacers 4L, 4R is the flow direction of the air oil 20 injected from the oil supply port of the center outer ring spacer 4M. Since it is opposite to the air, the cooling air 10 and the air oil 20 may collide with each other at the axially outer side portions 30 of the center rolling bearings 1B and 1C, and the air oil 20 may not flow smoothly. As a result, the oil of the air oil 20 is not sufficiently supplied to the axially outer portion 40, and an excessive temperature rise may occur.

  An object of the present invention is to efficiently cool a bearing device and a shaft supported by the bearing device in a bearing device in which three or more rolling bearings are arranged in the axial direction, and each rolling bearing is lubricated. It is providing the cooling structure which can supply the oil for use satisfactorily.

  In the cooling structure for a bearing device according to the present invention, three or more rolling bearings are arranged in the axial direction, and an outer ring spacer and an inner ring spacer are interposed between outer rings and inner rings of adjacent rolling bearings. An outer ring and an outer ring spacer are installed in a housing, and the inner ring and the inner ring spacer are fitted to a main shaft, and each outer ring spacer supplies a mixture of air and oil to the rolling bearing at its axial end. It is applied to a bearing device having an oil supply port. In the above bearing device, a cooling air discharge port for discharging cooling air toward the outer peripheral surface of the inner ring spacer is provided on the inner peripheral surface of each outer ring spacer, and adjacent to each other via the rolling bearing. Upstream in the flow direction of the air and oil mixture supplied to the intermediate rolling bearing, with respect to two outer ring spacers supplying the air and oil mixture from one outer ring spacer to the intermediate rolling bearing. The relationship between the flow rate or pressure of the cooling air discharged from the cooling air discharge port of the outer ring spacer positioned on the side and the cooling air discharge port of the outer ring spacer positioned on the downstream side is the downstream side. The cooling air discharged from the cooling air discharge port of the outer ring spacer located at the position where the air and oil mixture flow in the intermediate rolling bearing is not reversed. You .

  According to this configuration, the cooling air that is collided with the inner ring spacer is supported by the bearing device and the bearing device by discharging the cooling air from each cooling air discharge port toward the outer peripheral surface of the inner ring spacer. Take the heat of the other axis. Thereby, the bearing device and the shaft are efficiently cooled. In the intermediate rolling bearing, since the cooling air does not reverse the flow of the mixture of air and oil, the flow of the mixture of air and oil is not hindered by the cooling air in the intermediate rolling bearing, A mixture of air and oil is well supplied to the intermediate rolling bearing.

  In order to prevent the cooling air from reversing the flow of the air and oil mixture in the intermediate rolling bearing, for example, a cooling air supply device that supplies the cooling air to each cooling air discharge port The two outer ring spacers that are adjacent to each other through the intermediate rolling bearing are positioned on the upstream side by setting the flow rate of the cooling air supplied from the cooling air supply device to each cooling air discharge port. The flow rate of the cooling air discharged from the cooling air discharge port of the outer ring spacer is larger than the flow rate of the cooling air discharged from the cooling air discharge port of the outer ring spacer located on the downstream side. To do. The number of cooling air discharge ports for each outer ring spacer may be one or plural. When there are a plurality of cooling air, the cooling air flow rate discharged from the cooling air discharge port of the outer ring spacer means the total flow rate of cooling air discharged from each cooling air discharge port.

  As another example, for two outer ring spacers that are adjacent via the intermediate rolling bearing, the diameter of the cooling air discharge port of the outer ring spacer located on the downstream side is set between the outer rings located on the upstream side. The diameter of the cooling air discharge port of the seat is made larger. By changing the diameter of the cooling air discharge port between the downstream side and the upstream side, the pressure in the space between the outer ring spacer located on the downstream side and the inner ring spacer is changed to the outer ring spacer and the inner ring located on the upstream side. It becomes lower than the pressure of the space between the spacers. In this case, it is assumed that the flow rate of the compressed air discharged from each cooling air discharge port is the same. The number of cooling air discharge ports for each outer ring spacer may be one or plural, and in the case of a plurality, the cooling air discharged from each cooling air discharge port for each outer ring spacer It is assumed that the total air flow is the same.

  As still another example, for two outer ring spacers adjacent to each other via the intermediate rolling bearing, the number of the cooling air discharge ports of the outer ring spacer located on the upstream side is set to the outer ring located on the downstream side. More than the number of cooling air discharge ports of the spacer. By changing the number of cooling air discharge ports between the upstream side and the downstream side, the flow rate of the cooling air discharged from the cooling air discharge port of the outer ring spacer located on the upstream side is changed to the outer ring located on the downstream side. It becomes larger than the flow rate of the cooling air discharged from the cooling air discharge port of the spacer. Also in this case, it is assumed that the flow rate of the compressed air discharged from each cooling air discharge port is the same.

  In any of the above cases, since a pressure gradient of the cooling air is generated from the upstream side to the downstream side in the flow direction of the mixture of air and oil, the reverse flow of the cooling air in the intermediate rolling bearing does not occur. Thereby, the mixture of air and oil can be satisfactorily supplied to the intermediate rolling bearing.

  In the cooling structure for a bearing device according to the present invention, one outer ring spacer of two adjacent outer ring spacers via the intermediate rolling bearing supplies a mixture of air and oil to the intermediate rolling bearing. A second outer ring spacer having a first oil supply port supplies a mixture of air and oil to the rolling bearing at the end adjacent to the intermediate rolling bearing through the outer ring spacer. And the flow direction of the mixture of air and oil supplied from the first oil supply port to the intermediate rolling bearing, and the second oil supply port to the end rolling bearing. The flow direction of the mixture of air and oil is the same, from the intermediate rolling bearing to the rolling bearing at the end, between the other outer ring spacer and the inner ring spacer facing the outer ring spacer. Mix of air and oil through When an exhaust port for exhausting air out of the mixture of air and oil supplied to the intermediate and end rolling bearings is provided at one downstream end in the flow direction of the mixture of air and oil, good.

  The air in the mixture of air and oil supplied to each rolling bearing passes through each rolling bearing and is then discharged to the outside of the housing or the like through a discharge hole provided in the housing or the like in which the bearing device is accommodated. The If each rolling bearing is provided with an exhaust port that guides air from the inside of the rolling bearing to the discharge hole, the air flowing from the upstream side on the downstream side of the air flow direction in the exhaust pipe and the exhaust port to the exhaust pipe The flowing air collides with the air, making it difficult for the air to flow smoothly. Thereby, the flow of the mixture of air and oil in the rolling bearing is also deteriorated, and there is a possibility that the oil is not sufficiently supplied to the rolling bearing. On the other hand, if the exhaust port is provided at one location on the downstream end in the flow direction of the mixture of air and oil as in the above configuration, the air flowing through the exhaust port collides with the air flowing into the exhaust port from the exhaust port There are fewer places to do. Thereby, the flow of the mixture of air and oil in the rolling bearing is improved.

When the exhaust port is provided at the above location, an exhaust hole that leads to the outside of the bearing device by connecting to the exhaust port may be provided for each exhaust port.
With this configuration, the location where the air flowing through the exhaust hole collides with the air flowing into the exhaust hole from the exhaust port can be completely eliminated, and the flow of the mixture of air and oil in the rolling bearing can be further improved. Become.

In the cooling structure of the bearing device according to the present invention, an exhaust port for discharging the cooling air discharged from the cooling air discharge port from a space between the outer ring spacer and the inner ring spacer is provided on the outer ring spacer. You may provide in the same axial direction position as the said cooling air discharge outlet.
In this case, the cooling air discharged from the cooling air discharge port spreads in the axial direction in the space between the outer ring spacer and the inner ring spacer, but the axial flow of the cooling air does not occur. Therefore, it is difficult for a flow of cooling air to flow backward to the mixture of air and oil flowing through the intermediate rolling bearing.

  In the cooling structure of the bearing device of the present invention, the mixture of air and oil may be air oil that conveys liquid oil by air, or may be oil mist that conveys mist-like oil by air. .

  The cooling structure for a bearing device according to the present invention can be suitably used for supporting the spindle of a machine tool. In this case, the cooling effect of the main shaft is high, and lubricating oil can be satisfactorily supplied to each rolling bearing, so that operation in a high speed region is possible.

  In the cooling structure for a bearing device according to the present invention, three or more rolling bearings are arranged in the axial direction, and an outer ring spacer and an inner ring spacer are interposed between outer rings and inner rings of adjacent rolling bearings. An outer ring and an outer ring spacer are installed in a housing, and the inner ring and the inner ring spacer are fitted to a main shaft, and each outer ring spacer supplies a mixture of air and oil to the rolling bearing at its axial end. In the bearing device having an oil supply port, a cooling air discharge port for discharging cooling air toward the outer peripheral surface of the inner ring spacer is provided on the inner peripheral surface of each outer ring spacer, and the rolling bearing is interposed therebetween. The flow of the mixture of air and oil supplied to the intermediate rolling bearing is adjacent to the two outer ring spacers that supply the mixture of air and oil from one outer ring spacer to the intermediate rolling bearing. Direction, The relationship between the flow rate or pressure of the cooling air discharged from the cooling air discharge port of the outer ring spacer located on the flow side and the cooling air discharge port of the outer ring spacer located on the downstream side is the downstream side. Since the cooling air discharged from the cooling air discharge port of the outer ring spacer located on the side has a relationship that does not reverse the flow of the mixture of air and oil in the intermediate rolling bearing, the bearing The device and the shaft supported by the bearing device can be efficiently cooled, and the oil for lubrication can be satisfactorily supplied to each rolling bearing.

(A) Sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on one Embodiment of this invention, (B) is the elements on larger scale. It is a figure which shows the upper half of sectional drawing which cut | disconnected the main spindle apparatus in the cross section different from FIG. It is sectional drawing which cut | disconnected the spindle apparatus by the plane perpendicular | vertical to an axial direction. It is a figure which shows the upper half of sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on different embodiment of this invention. It is a figure which shows the upper half of sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on further different embodiment of this invention. It is sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on further different embodiment of this invention. It is a figure which shows the lower half of sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on further different embodiment of this invention. It is a figure which shows the lower half of sectional drawing of the main axis | shaft apparatus incorporating the bearing apparatus provided with the cooling structure which concerns on further different embodiment of this invention. It is a figure which shows the upper half of sectional drawing of the main axis | shaft apparatus in which the bearing apparatus provided with the conventional cooling structure was integrated. It is explanatory drawing for demonstrating the subject of an air discharge path | route.

A bearing device cooling structure according to an embodiment of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of a cooling structure for a bearing device according to the present invention. Although the example of a figure shows the state where the bearing apparatus J was integrated in the spindle apparatus of the machine tool, it is not limited to a machine tool. As shown in FIG. 1, in this bearing device J, four rolling bearings 1A, 1B, 1C, 1D are arranged side by side in the axial direction, and between each outer ring 2 and between each inner ring 3 of adjacent rolling bearings, Outer ring spacers 4L, 4M, 4R and inner ring spacers 5L, 5M, 5R are interposed, respectively.

  In the bearing device J, the outer rings 2 and outer ring spacers 4L, 4M, and 4R of the rolling bearings 1A, 1B, 1C, and 1D are fitted to the inner peripheral surface of the housing 6, and each of the rolling bearings 1A, 1B, 1C, and 1D is fitted. Inner ring 2 and inner ring spacers 5L, 5M, 5R are fitted to the outer peripheral surface of main shaft 7 of the machine tool. For example, the outer ring 2 and the outer ring spacer 4 have a clearance fit with respect to the housing 6, and the inner ring 3 and the inner ring spacer 5 have an interference fit with respect to the shaft 7. The outer ring 2 of the rolling bearing 1D at the right end of the figure is positioned in the axial direction by the step portion 6a of the housing 6, and the inner ring 3 of the rolling bearing 1D is positioned in the axial direction by the step portion 7a of the main shaft 7. Further, the outer ring holder 31 is pressed against the outer ring 2 of the rolling bearing 1A at the left end of the figure, and the positioning spacer 33 is pressed against the inner ring 3 of the rolling bearing 1A by tightening the nut 32, whereby the bearing device J is The housing 6 is fixed with a preload applied thereto.

  The main shaft 7 is rotated by a motor (not shown) built in the housing 6 or a motor (not shown) outside the housing 6. The rotation direction of the main shaft 7 by the motor may be switched between forward and reverse. In that case, the “rotation direction” in this specification refers to the forward rotation direction of the main shaft 7.

  Each of the rolling bearings 1A, 1B, 1C, and 1D is an angular ball bearing, and has a plurality of rolling elements 8 between the raceway surfaces of the inner and outer rings 3 and 2, and these rolling elements 8 are circumferentially arranged by a cage 9. Is retained. The left two rolling bearings 1A, 1B and the right two rolling bearings 1C, 1D are both in parallel combination with each other, and the central two rolling bearings 1B, 1C are in back combination with each other. The outer ring 2 of each rolling bearing 1A, 1B, 1C, 1D and the outer ring spacers 4L, 4M, 4R are installed in the housing 6 of the main shaft unit, and the inner ring 3 of each rolling bearing 1A, 1B, 1C, 1D and between the inner rings. The seats 5L, 5M, 5R are fitted on the outer peripheral surface of the main shaft 7.

The cooling structure of the bearing device J will be described.
As shown in FIGS. 1 and 3, there is a radial clearance δ (FIG. 1B between the inner peripheral surface of each outer ring spacer 4L, 4M, 4R and the outer peripheral surface of each inner ring spacer 5L, 5M, 5R. )) Is provided, and cooling air discharge ports for discharging cooling air 10 toward the outer peripheral surfaces of the inner ring spacers 5L, 5M, and 5R are provided on the inner peripheral surfaces of the outer ring spacers 4L, 4M, and 4R. 11L, 11M, and 11R are provided. These cooling air discharge ports 11L, 11M, and 11R are provided at a plurality of locations, for example, at equal intervals in the circumferential direction. The cooling air discharge ports 11L, 11M, and 11R may be provided for each outer ring spacer 4L, 4M, and 4R.

  In the case of this embodiment, as shown in FIG. 3, the cooling air discharge ports 11L, 11M, and 11R are inclined in the air discharge direction forward in the rotational direction L1 of the inner ring 3 and the main shaft 7. That is, each of the cooling air discharge ports 11L, 11M, and 11R is linear, and from an arbitrary radial straight line L2 in a cross section perpendicular to the axis of the outer ring spacer 4, a direction orthogonal to the straight line L2. Is offset (offset amount OS) and is parallel to the straight line L2. Further, the inner ring spacer 5 is provided with a plurality of holes 12 that penetrate in the radial direction at the same axial position as the cooling air discharge ports 11L, 11M, and 11R and are equally distributed in the circumferential direction.

An annular introduction groove 13 for introducing the cooling air 10 is provided on the outer peripheral surfaces of the outer ring spacers 4L, 4M, 4R. The introduction groove 13 is provided in an axially intermediate portion on the outer peripheral surface of the outer ring spacers 4L, 4M, 4R, and is connected to each cooling through a connection hole 13a extending in the same direction as each cooling air discharge port 11L, 11M, 11R. The air discharge ports 11L, 11M, and 11R are in communication. From the cooling air supply device 14 such as a blower provided outside the bearing device J, the cooling air 10 is supplied to the introduction groove 13 through the cooling air introduction holes 15 ₁ and 15 ₂ provided in the housing 6. The Specifically, the compressed air in the cooling air discharge opening 11M provided at the center of the outer ring spacer 4M supplied by a cooling air introduction hole 15 _1, seat between the left and right of the outer ring by the air introduction hole 15 ₂ for the two cooling Compressed air is supplied to cooling air discharge ports 11L and 11R provided in 4L and 4R, respectively.

In this embodiment, the cooling air discharge ports 11L, 11M and 11R have the same diameter, but the flow rate of the cooling air 10 sent from the cooling air supply device 14 to the cooling air introduction holes 15 ₁ and 15 _2. Are different from each other, the flow rate of the cooling air 10 discharged from the cooling air discharge port 11M provided in the central outer ring spacer 4M is the cooling flow provided in the outer ring spacers 4L and 4M on both sides. Air discharge port 11L. The flow rate of the cooling air 10 discharged from 11R is increased. The flow rate of the cooling air 10 delivered from the cooling air supply device 14 is adjusted by, for example, a flow rate adjustment valve. For example, when the flow rate of the cooling air 10 discharged from the cooling air discharge port 11M is “100”, the cooling air discharge port 11L. The flow rate of the cooling air 10 discharged from 11R is set to “50”.

  In other words, two outer ring spacers 4M and 4L (4M) that are adjacent to each other via the rolling bearing 1B (1C) and supply air oil 20 described later from one outer ring spacer 4M to the intermediate rolling bearing 1B (1C). , 4R), the flow rate of the cooling air 10 discharged from the cooling air discharge port 11M of the outer ring spacer 4M located upstream in the flow direction of the air oil 20 supplied to the intermediate rolling bearing 1B (1C). Is larger than the flow rate of the cooling air 10 discharged from the cooling air discharge port 11L (11R) of the outer ring spacer 4L (4R) located on the downstream side. The reason for this will be described in detail later.

  The outer ring spacers 4L, 4M, 4L are provided with outlets 17 for cooling air 10 formed of notches on both end surfaces in the axial direction. By arranging the outer ring 2 of the rolling bearings 1A, 1B, 1C, 1D adjacent to the outer ring spacers 4L, 4M, 4R, the notches become the outer ring spacers 4L, 4M, 4R and the inner ring spacers 5L, It becomes the discharge port 17 which communicates the space between 5M and 5R and the outside of the bearing device J. An exhaust hole 18 is provided in the housing 6, and the exhaust hole 18 communicates with the discharge port 17 of each outer ring spacer 4L, 4M, 4R via a connection hole 19.

Next, the lubricating structure of the bearing device J will be described.
The bearing device J is lubricated by a mixture of oil and air, for example, air oil that conveys liquid oil by air. Instead of air oil, an oil mist that conveys mist-like oil by air may be used.

As shown in FIG. 2, oil supply ports 21 ₁ and 21 _{2 for} supplying air oil 20 to the bearing spaces of the rolling bearings 1A, 1B, 1C, and 1D are provided on the end surfaces of the outer ring spacers 4L, 4M, and 4R. . Specifically, the center of the outer ring spacer 4M has on both sides of the rolling bearing 1B, the first oil supply port 21 ₁ for supplying each 1C air-oil 20 on both end faces. Outer ring spacer 5L, 5R at both ends, has adjacent opposite ends of the rolling bearing 1A, the second supplying air-oil 20 each 1D oil supply port 21 ₂ to the end surface of the other.

The outer ring spacers 4L, 4M, 4R are provided with oil introduction holes 23 communicating with the oil supply ports 21 ₁ , 21 ₂ . The oil introduction hole 23 is formed at a predetermined depth radially inward from the outer peripheral surface of the outer ring spacers 4L, 4M, and 4R, and communicates with the oil supply ports 21 ₁ and 21 ₂ near the hole bottoms. Each oil supply port 21 ₁ , 21 ₂ is formed in a through hole shape that is inclined so as to reach the inner diameter side from the oil introduction hole 23 toward the rolling bearings 1A, 1B, 1C, 1D. The air oil 20 is supplied from the air oil supply device 24 provided outside the bearing device J to the oil introduction hole 23 through the air oil supply hole 25 provided in the housing 6.

  In the bearing device J, the cooling air 10 sent from the cooling air supply device 14 is supplied to each outer ring spacer as shown by a white arrow in the partially enlarged view of FIG. The air is discharged from the cooling air discharge ports 11L, 11M, and 11R of 4L, 4M, and 4R toward the outer peripheral surfaces of the inner ring spacers 5L, 5M, and 5R. As a result, the inner ring spacers 5L, 5M, 5R are cooled, and the spindle 7 is cooled by the cooled inner ring spacers 5L, 5M, 5R. Further, since the holes 12 are provided in the inner ring spacers 5L, 5M, and 5R at the same axial position as the cooling air discharge ports 11L, 11M, and 11R, the holes are discharged from the cooling air discharge ports 11L, 11M, and 11R. Further, the cooling air 10 directly hits the main shaft 7 through the hole 12 and can cool the main shaft 7 efficiently. Since the air discharge direction of each cooling air discharge port 11L, 11M, 11R is inclined forward in the rotational direction L1 of the inner ring 3 and the main shaft 7, the cooling air 10 is an outer peripheral surface of the inner ring spacers 5L, 5M, 5R. And when it hits the wall surface of the hole 12, the injection force of the cooling air 10 can be given to the inner ring spacers 5L, 5M, 5R, and the effect of driving the main shaft 7 can be expected.

  Most of the cooling air 10 discharged from the cooling air discharge ports 11L, 11M, and 11R is a discharge port 17 of the outer ring spacers 4L, 4M, and 4R provided with the cooling air discharge ports 11L, 11M, and 11R. From the main shaft device J through the connection hole 19 and the exhaust hole 18. The flow rate of the cooling air 10 discharged from the cooling air discharge port 11M provided in the central outer ring spacer 4M is the same as that of the cooling air discharge ports 11L. Since the flow rate of the cooling air 10 discharged from 11R is increased, the pressure in the space between the central outer ring spacer 4M and the inner ring spacer 5M is different from that of the outer outer ring spacer 4L (4R). The pressure in the space between the inner ring spacer 5L (5R) is higher. Therefore, a part of the cooling air 10 discharged from the cooling air discharge port 11M passes through the rolling bearings 1B (1C) on both sides, and the outer outer ring spacer 4L (4R) and the inner ring spacer 5L (5R). However, the space between the outer outer ring spacer 4L (4R) and the inner ring spacer 5L (5R) from the outer outer ring spacer 4M to the space between the inner outer ring spacer 4M and the inner ring spacer 5M The cooling air 10 does not flow.

Further, during operation of the bearing device J, etc., the air oil 20 sent from the air oil supply device 24 is sent to the first oil supply port 21 _{1 as} shown by the intermediate coating arrow in the partially enlarged view of FIG. from being supplied to the bearing space of the center of the rolling bearing 1B (1C), and is respectively supplied to the bearing space of the second oil supply port 21 ₂ from both ends rolling 1A (1D). As described above, the pressure in the space between the outer ring spacers 4L, 4M, 4R and the inner ring spacers 5L, 5M, 5R is higher at the center than at the outside. That is, the pressure gradient of the cooling air 10 is created from the upstream side to the downstream side in the flow direction of the air oil 20. Therefore, in the intermediate rolling bearing 1B (1C), the flow of the cooling air 10 does not reverse the air flow of the air oil 20. Therefore, the air of the air oil 20 flows smoothly, and the oil can be satisfactorily supplied to the rolling bearings 1A, 1B, 1C, 1D.

  FIG. 4 shows a second embodiment of the present invention. Compared with the first embodiment, the cooling structure of the bearing device J is such that the air oil 20 supplied to the intermediate rolling bearing 1B (1C) for the two adjacent outer ring spacers 4M, 4L (4M, 4R). The diameter of the cooling air discharge port 11L (11R) of the outer ring spacer 4L (4R) located on the downstream side of the diameter D1 of the cooling air discharge port 11M of the outer ring spacer 4M located on the upstream side in the flow direction of The difference is that D2 is increased. The flow rates of the cooling air 10 supplied from a cooling air supply device (not shown) and discharged from the cooling air discharge ports 11L, 11M, 11R are the same. The other configuration is the same as that of the first embodiment.

  In the case of this configuration, by defining the diameters D1 and D2 of the cooling air discharge ports 11M and 11L (11R) as described above, the outer ring spacer 4L (4R) and the inner ring spacer 5L (5R) located on the downstream side. ) Is lower than the pressure in the space between the outer ring spacer 4M and the inner ring spacer 5M located on the upstream side. Thereby, the pressure gradient of the cooling air 20 is created from the upstream side in the flow direction of the air oil 20 to the downstream side, and the backward flow of the cooling air 10 in the intermediate rolling bearing 1B (1C) can be prevented.

  FIG. 5 shows a third embodiment of the present invention. The cooling structure of the bearing device J is different from that of the first embodiment in that two cooling air discharge ports 11M are provided in the central outer ring spacer 4M. In other words, for the two adjacent outer ring spacers 4M, 4L (4M, 4R), the outer ring spacer 4M located upstream in the flow direction of the mixture of the air oil 20 supplied to the intermediate rolling bearing 1B (1C). The number of cooling air discharge ports 11M was made larger than the number of cooling air discharge ports 11L (11R) of the outer ring spacer 4L (4R) located on the downstream side. The flow rates of the cooling air 10 supplied from a cooling air supply device (not shown) and discharged from the cooling air discharge ports 11L, 11M, 11R are the same. The other configuration is the same as that of the first embodiment.

  In this case, the flow rate of the cooling air 10 discharged from the cooling air discharge port 11M of the outer ring spacer 4M located on the upstream side by providing the two cooling air discharge ports 11M in the central outer ring spacer 4M. However, it becomes larger than the flow volume of the cooling air 10 discharged from the cooling air discharge port 11L (11R) of the outer ring spacer 4L (4R) located on the downstream side. Thereby, the pressure gradient of the cooling air 20 is created from the upstream side in the flow direction of the air oil 20 to the downstream side, and the backward flow of the cooling air 10 in the intermediate rolling bearing 1B (1C) can be prevented.

  FIG. 6 shows a fourth embodiment of the present invention. The cooling structure of this bearing device J is such that in each outer ring spacer 4L, 4M, 4R, the cooling air 10 and the air exhaust port 17 of the air oil 20 are in the same axial position as the cooling air discharge ports 11L, 11M, 11R. Is provided. Accordingly, the connection hole 19 is also in the same axial position as the exhaust port 17. By arranging the exhaust port 17 as described above, the cooling air 10 discharged from the cooling air discharge ports 11L, 11M, and 11R is exchanged between the outer ring spacers 4L, 4M, and 4R and the inner ring spacers 5L, 5M, and 5R. It spreads in the axial direction in the space between, but it becomes difficult to flow in the axial direction. Therefore, it is difficult for the cooling air 10 to flow backward to the flow of the air oil 20 flowing through the intermediate rolling bearing 1B (1C).

  FIG. 7 and FIG. 8 show embodiments in which the discharge paths of the cooling air 10 and air oil 20 (hereinafter collectively referred to as “air”) are different from those of the first embodiment. In the exhaust path of the first embodiment, air is discharged from the exhaust ports 17 of the outer ring spacers 4L, 4M, 4R as shown in FIG. Since it is involved in the discharge of air, it cannot be accurately determined from which exhaust port 17 it is likely to be discharged. In general, the exhaust port 17 close to the atmosphere opening port 26 tends to be easily discharged, and the distant exhaust port 17 tends to be difficult to be discharged. In addition, the air flowing through the holes 18 and 19 collides with each other at the portion 41 where the exhaust hole 18 and the connection hole 19 intersect, so that it becomes difficult for the air to flow smoothly. Then, the exhaustability of air from the exhaust port 17 deteriorates, and the oil of the air oil 20 may stay and cause seizure or the like.

  The cooling structure of the bearing device J shown in FIG. 7 eliminates the discharge port 17 provided in each outer ring spacer 4L, 4M, 4R in the first embodiment, and becomes a downstream end in the flow direction of the air oil 20. The exhaust port 17 was provided only at one place. Thereby, the location where the air which flows through the exhaust hole 18 and the air which flows into the exhaust hole 18 from the exhaust port 17 collide decreases, and the flow of the air oil 20 in the rolling bearings 1A, 1B, 1C and 1D becomes good.

  In addition, the cooling structure of the bearing device J shown in FIG. Provided. Thereby, the location where the air flowing through the exhaust hole 18 and the air flowing into the exhaust hole 18 from the exhaust port 17 collide can be completely eliminated, and the flow of the air oil 20 in the rolling bearings 1A, 1B, 1C, 1D can be further reduced. It can be made even better.

  As is apparent from the description of the above embodiments, the cooling structure of the bearing device J of the present invention has a high cooling effect on the bearing device J and the main shaft 7 supported by the bearing device J, and each rolling bearing 1A, 1B, Since oil for lubrication can be satisfactorily supplied to 1C and 1D, the spindle device can be operated in a high-speed region. Therefore, this bearing device J can be suitably used for supporting the main shaft 7 of the machine tool.

DESCRIPTION OF SYMBOLS 1A, 1B, 1C, 1D ... Rolling bearing 2 ... Outer ring 3 ... Inner ring 4L, 4M, 4R ... Outer ring spacer 5L, 5M, 5R ... Inner ring spacer 6 ... Housing 7 ... Main shaft 10 ... Cooling air 11L, 11M, 11R Air outlet for cooling 17 Air outlet 18 Air outlet 20 Air oil (mixture of air and oil)
DESCRIPTION OF SYMBOLS 21 ... Oil supply port 21 ₁ ... 1st oil supply port 21 ₂ ... 2nd oil supply port J ... Bearing apparatus

Claims (8)

Three or more rolling bearings are arranged in the axial direction, an outer ring spacer and an inner ring spacer are interposed between outer rings and inner rings of adjacent rolling bearings, and the outer ring and outer ring spacers are installed in the housing. In the bearing device, the inner ring and the inner ring spacer are fitted to a main shaft, and each outer ring spacer has an oil supply port at its axial end for supplying a mixture of air and oil to the rolling bearing.
Provided on the inner peripheral surface of each outer ring spacer is a cooling air discharge port for discharging cooling air toward the outer peripheral surface of the inner ring spacer, and are adjacent to each other via the rolling bearing. On the other hand, for two outer ring spacers that supply the air and oil mixture from one outer ring spacer, the outer ring located on the upstream side in the flow direction of the air and oil mixture supplied to the intermediate rolling bearing The relationship between the cooling air flow rate or pressure discharged from the cooling air discharge port of the spacer and the cooling air discharge port of the outer ring spacer located on the downstream side is between the outer rings located on the downstream side. The cooling of the bearing device is characterized in that the cooling air discharged from the cooling air discharge port of the seat has a configuration that does not reverse the flow of the mixture of air and oil in the intermediate rolling bearing. Construction.   The cooling structure for a bearing device according to claim 1, further comprising a cooling air supply device that supplies cooling air to each of the cooling air discharge ports, and from the cooling air supply device to each cooling air discharge port. Depending on the setting of the flow rate of the cooling air to be supplied, for the two outer ring spacers adjacent to each other via the intermediate rolling bearing, the cooling air discharged from the cooling air discharge port of the outer ring spacer located on the upstream side A bearing structure cooling structure in which an air flow rate is made larger than a cooling air flow rate discharged from the cooling air discharge port of the outer ring spacer located on the downstream side.   In the cooling structure of the bearing device according to claim 1, the diameter of the cooling air discharge port of the outer ring spacer located on the downstream side is set between two outer ring spacers adjacent to each other via the intermediate rolling bearing. A cooling structure for a bearing device that is larger than the diameter of the cooling air discharge port of the outer ring spacer located on the upstream side.   The cooling structure of the bearing device according to claim 1, wherein the number of the cooling air discharge ports of the outer ring spacer located on the upstream side is determined for two adjacent outer ring spacers via the intermediate rolling bearing. The cooling structure of the bearing device in which the number of the cooling air discharge ports of the outer ring spacer located on the downstream side is increased. 5. The cooling structure for a bearing device according to claim 1, wherein one outer ring spacer of the two outer ring spacers adjacent to each other via the intermediate rolling bearing is the intermediate rolling element. A first oil supply port for supplying a mixture of air and oil to the bearing, and the other outer ring spacer is connected to the rolling bearing at the end adjacent to the intermediate rolling bearing through the outer ring spacer. A second oil supply port for supplying a mixture of air and oil,
The flow direction of the mixture of air and oil supplied from the first oil supply port to the intermediate rolling bearing, and the mixture of air and oil supplied from the second oil supply port to the end rolling bearing. The flow direction is the same, and from the intermediate rolling bearing to the end rolling bearing, a mixture of air and oil passes between the other outer ring spacer and the inner ring spacer facing the outer ring spacer. flow,
Cooling of a bearing device in which an exhaust port for exhausting air out of a mixture of air and oil supplied to each of the intermediate and end rolling bearings is provided at one downstream end in the flow direction of the mixture of air and oil. Construction.   6. The cooling structure for a bearing device according to claim 5, wherein an exhaust hole that leads to the outside of the bearing device and is connected to the exhaust port is provided for each of the exhaust ports.   The cooling structure for a bearing device according to any one of claims 1 to 6, wherein the mixture of air and oil carries air oil that carries liquid oil by air or mist-like oil by air. Cooling structure of bearing device that is oil mist.   The cooling structure for a bearing device according to any one of claims 1 to 7, which is used for supporting a main shaft of a machine tool.

Images