JP6385090B2 - Cooling structure of bearing device - Google Patents

Description

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

  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 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, the shaft and the bearing are cooled by injecting cold air into the space between the two bearings at an angle in the rotational direction to form a swirling flow.

JP 2000-161375 A

  In cooling with compressed air, the compressed air is not blown directly onto the shaft or bearing because of lubrication, etc., but it is blown from the nozzle provided in the outer ring spacer to the inner ring spacer, and the shaft and bearing via the inner ring spacer. Is often cooled. In that case, the compressed air discharged from the nozzle is exhausted to the outside of the bearing after taking heat of the inner ring spacer while flowing in the axial direction along the outer peripheral surface of the inner ring spacer. This air cooling system has a higher cooling effect as the flow rate of compressed air is higher and the flow rate is higher.

  However, in the case of a nozzle having a simple shape in which the hole diameter in the vicinity of the outlet is simply squeezed, a large cooling effect cannot be expected because choking is performed at the nozzle outlet and the flow velocity does not become higher than the speed of sound. In order to make the flow velocity faster than the sonic velocity, it is necessary to make a very high speed nozzle with a small change in the hole diameter, such as a Laval nozzle, etc., but such a complicated nozzle hole is made of a metal material. It is difficult to machine the outer ring spacer by cutting.

  Even if the flow rate of the compressed air is increased in order to increase the cooling effect, the flow rate depends on the capacity of the air compressor, and therefore the flow rate cannot be increased as much as possible. By providing an air hole that communicates with the outside of the bearing device in the middle of the compressed air flow direction of the nozzle hole, air can be taken in from the outside of the bearing and the flow rate of cooling air can be increased. It is difficult to cut a hole in an outer ring spacer made of a metal material by cutting.

  Furthermore, it may be desirable to make the cross-sectional shape perpendicular to the flow direction of the compressed air in the nozzle hole non-circular, but in this case as well, the nozzle of the non-circular hole is processed by cutting into an outer ring spacer made of a metal material. It is difficult to do.

  An object of the present invention is to cool a bearing device that can efficiently cool the bearing device with compressed air, and can provide a nozzle hole having a shape according to the application in the fixed side spacer with high accuracy and high productivity. Is to provide a structure.

The bearing structure cooling structure of the premise includes a stationary spacer and a rotating spacer adjacent to the stationary bearing ring and the rotating bearing ring facing the inside and outside of the rolling bearing, respectively. A bearing device in which a fixed spacer is installed on a fixed member of a fixed member and a rotating member, and the rotating raceway and the rotating spacer are installed on a rotating member of the fixed member and rotating member. Applied. In this bearing device, the fixed side spacer is provided with a nozzle hole for discharging compressed air for cooling toward a circumferential surface where the rotary side spacers face each other, and the nozzle hole is formed on the fixed side spacer. A portion that inclines forward in the rotation direction of the rotary side spacer with respect to a normal passing through the center of the outlet of the nozzle hole on the peripheral surface of the spacer and constitutes the nozzle hole in the fixed side spacer. Separately from other parts, the nozzle hole has a non-uniform shape in one or both of a cross section perpendicular to the flow direction of the compressed air and a vertical cross section along the flow direction of the compressed air. It is characterized by. For example, the stationary side race is an outer race and the rotation side race is an inner race. In this case, the fixing member and the rotating member are, for example, a housing and a shaft, respectively.

  According to this configuration, the compressed air for cooling is discharged from the nozzle hole provided in the fixed side spacer toward the peripheral surface of the rotation side spacer, so that the rotation side spacer is first cooled. The rotating side bearing ring and the rotating shaft of the rolling bearing are cooled via the. Since the nozzle hole provided in the fixed spacer is inclined forward in the rotational direction of the rotating spacer, the compressed air discharged from the nozzle hole is swung along the peripheral surface of the rotating spacer It flows in the direction and is discharged to the outside of the bearing. Since the compressed air swirls, it takes a longer time for the compressed air to contact the peripheral surface of the rotating spacer compared to the case where it flows straight in the axial direction, and the rotating spacer can be efficiently cooled. For this reason, the effect which cools a bearing apparatus and a rotating shaft is high.

  By making the portion constituting the nozzle hole in the stationary spacer different from the other portions, the portion constituting the nozzle hole can be made of a material that can be easily processed, such as a resin material. As a result, nozzle holes in which the shape of one or both of the cross section perpendicular to the flow direction of the compressed air and the vertical cross section along the flow direction of the compressed air are not uniform are produced in the fixed spacer with high accuracy. Can be provided with good performance. Such nozzle holes are difficult to machine by cutting, but can be easily manufactured by injection molding of a resin material.

In this invention, when the fixed side spacer has a plurality of the nozzle holes in the circumferential direction, it is preferable that the portions constituting the respective nozzle holes are individually fitted into the fitting holes provided in the other portions. .
If the parts that make up each nozzle hole are common, the parts that make up the nozzle hole have an annular shape or a shape close to a ring, and the other parts are divided on both sides in the axial direction across the parts that make up each nozzle hole. It becomes a form. In this embodiment, when the portion constituting the nozzle hole is a resin material, the axial rigidity of the fixed side spacer is reduced. If the parts constituting each nozzle hole are individually fitted into the fitting holes provided in the other parts, the other parts are not divided on both sides in the axial direction, so the axial direction of the fixed side spacer It is possible to prevent a decrease in rigidity.

Cooling structure of the bearing device of the present invention to definitive first invention, the premise construction smell Te, cross-sectional shape of the vicinity of an outlet of the nozzle holes, the axial direction dimension is long flat shape compared to circumferential dimension . The flat shape referred to in this specification is not limited to a flat shape whose axial dimension is extremely long compared to the circumferential dimension, but a shape whose axial dimension is slightly longer than the circumferential dimension. Including.
When a large amount of compressed air is discharged from the nozzle hole toward the rotary spacer, the flow rate of the compressed air becomes the maximum speed (for example, sound speed) at the outlet of the nozzle hole. At this time, when the clearance between the nozzle hole outlet and the rotary spacer is narrow and the cross-sectional shape in the vicinity of the nozzle hole outlet is circular, the pressure between the nozzle hole outlet and the fixed spacer is high. Compressive waves are generated easily. When the compression wave is generated, the straight flow of the compressed air discharged from the outlet of the nozzle hole is inhibited and diffused in the axial direction. Thereby, the time for the compressed air to contact the peripheral surface of the rotating spacer is shortened, and the cooling effect is reduced.
When the cross-sectional shape in the vicinity of the nozzle hole outlet is circular, compression waves are likely to occur because the amount of compressed air flowing into the gap between the nozzle hole outlet and the rotating spacer (mass flow rate) This is considered to be due to a local increase in the central portion in the axial direction on the extension line of the center of the nozzle hole. If the cross-sectional shape near the outlet of the nozzle hole is a flat shape, the amount of compressed air inflow is equalized in the axial direction, so strong compression waves do not occur and compressed air does not diffuse in the axial direction, Can flow in the circumferential direction.

In this invention, the longitudinal section of the nozzle hole may have a shape in which the middle portion in the length direction is narrow and allows supersonic flow.
In this case, the flow rate of the compressed air discharged from the nozzle hole is increased, and the cooling effect is improved.

Cooling structure of the bearing device of the present invention to definitive second invention, the premise construction smell Te, the intermediate portion of the compressed air flow direction of the nozzle holes, those digits set the air hole communicating with the bearing device outside .
In this case, air is sucked into the nozzle hole from the outside of the bearing device through the air hole due to the negative pressure generated by the dynamic pressure of the compressed air flowing through the nozzle hole. Thereby, the flow rate discharged from the nozzle hole is increased and the cooling effect is improved.

In the present invention, an annular recess may be provided on the peripheral surface of the fixed spacers facing each other, and the nozzle hole may be provided by opening an outlet in the recess.
In this case, the compressed air is discharged from the nozzle hole into the space of the recessed portion, so that the compressed air is adiabatically expanded, the temperature of the compressed air is lowered and the flow velocity is increased. Thereby, a cooling effect improves.
In addition, if a recess is provided, compressed air flows from the space of the recess to a gap between the fixed spacer and the rotary spacer that is narrower than this, so the circumferential direction of the compressed air that flows through the gap The flow velocity of each part is made uniform, and the flow velocity of the compressed air flowing into the bearing becomes uniform. Thereby, the collision sound between the compressed air and the rotating rolling element can be reduced.

The cooling structure of the bearing device of the first invention in the inventions, the fixed side raceway and the rotating side raceway between rings on the fixed side adjacent each seat and the rotation-side spacer facing is provided on the inside and outside of the rolling bearing, The fixed side raceway and the fixed side spacer are installed on a fixed member of the fixed member and the rotary member, and the rotary side raceway and the rotary side spacer are on the rotary member of the fixed member and the rotary member. In the bearing device to be installed, the stationary spacer is provided with a nozzle hole for discharging compressed air for cooling toward the circumferential surface where the spacers of the rotating side are opposed to each other. The nozzle hole in the fixed side spacer is inclined forward with respect to the normal line passing through the center of the outlet of the nozzle hole in the peripheral surface of the fixed side spacer, thereby forming the nozzle hole in the fixed side spacer. Make the part separate from other parts The nozzle hole is not said in the shape of one or both of the cross-section of the cross section and longitudinal section along the flow direction of the compressed air perpendicular to the flow direction of the compressed air is uniform, cross-section near the outlet of the nozzle hole shape, because the axial dimension as compared to the circumferential dimension has a long flat shape, the compressed air can be a bearing device efficiently cooled, and the fixed-side spacer the shape of the nozzle hole according to the application Can be provided with high accuracy and high productivity .
According to a second aspect of the present invention, there is provided a cooling structure for a bearing device, wherein a stationary spacer and a rotating spacer are provided adjacent to a stationary bearing ring and a rotating bearing ring facing the inside and outside of a rolling bearing, respectively. The stationary side race ring and the stationary side spacer are installed on a stationary member of the stationary member and the rotating member, and the rotational side race ring and the rotational side spacer are installed on the rotating member of the stationary member and the rotational member. In the bearing device, the fixed side spacer is provided with a nozzle hole for discharging compressed air for cooling toward the circumferential surface where the rotary side spacers face each other, and the nozzle hole is fixed to the fixed side spacer. A portion that inclines forward in the rotation direction of the rotary side spacer with respect to a normal passing through the center of the outlet of the nozzle hole in the peripheral surface of the side spacer, and constitutes the nozzle hole in the fixed side spacer Separate from other parts The shape of one or both of the cross section perpendicular to the flow direction of the compressed air and the vertical cross section along the flow direction of the compressed air is not uniform in the nozzle hole, and the flow of the compressed air in the nozzle hole Since the air hole communicating with the outside of the bearing device is provided in the middle part of the direction, the bearing device can be efficiently cooled by compressed air, and the nozzle hole having a shape according to the application is provided in the fixed side spacer with high accuracy. It can be provided with high productivity.

It is sectional drawing of the machine tool spindle apparatus provided with the cooling structure of the bearing apparatus which concerns on one Embodiment of this invention. It is an expanded sectional view of the principal part of the cooling structure of the bearing device. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a disassembled perspective view of the nozzle attachment part of the cooling structure of the same bearing device. It is sectional drawing of the principal part of the cooling structure of the bearing apparatus which concerns on different embodiment of this invention. It is sectional drawing of the principal part of the cooling structure of the bearing apparatus which concerns on further different embodiment of this invention. It is sectional drawing of the cooling structure of the bearing apparatus which concerns on further different embodiment of this invention. It is the figure which looked at the peripheral part of the nozzle exit of the cooling structure of the said bearing apparatus from the axial direction. In the IX-IX sectional view of FIG. 8, (A) and (B) show different examples. It is a figure which shows the pressure distribution near the exit of a nozzle hole in the state in which the compression wave has generate | occur | produced. It is a figure which shows temperature distribution near the exit of a nozzle hole in the state in which the compression wave has generate | occur | produced. (A), (B), (C) is a figure which shows the relationship between the cross-sectional shape of the exit vicinity of a nozzle hole, and mass flow rate.

  A cooling structure for a bearing device according to an embodiment of the present invention will be described with reference to FIGS. The cooling structure of the bearing device in this 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. 1, the bearing device J includes two rolling bearings 1 and 1 arranged in the axial direction, and an outer ring spacer 4 between the outer rings 2 and 2 and between the inner rings 3 and 3 of each rolling bearing 1 and 1. And an inner ring spacer 5 are interposed. The outer ring 2 and the outer ring spacer 4 are installed in the housing 6, and the inner ring 3 and the inner ring spacer 5 are fitted to the main shaft 7. The rolling bearing 1 is an angular ball bearing, and a plurality of rolling elements 8 are interposed between the raceway surfaces of the inner and outer rings 3 and 2. The rolling elements 8 are held by the cage 9 at an equal circumference. The two rolling bearings 1 and 1 are arranged in combination with each other on the back surface, and are used by setting the initial preload of each rolling bearing 1 and 1 depending on the width dimension difference between the outer ring spacer 4 and the inner ring spacer 5.
In this embodiment, the rolling bearing 1 is used for inner ring rotation. Therefore, the outer ring 2 and the inner ring 3 are the “fixed side race ring” and “rotation side race ring”, respectively, and the outer ring spacer 4 and the inner ring spacer 5 are “fixed side spacer” and “rotation side”. It ’s a “space”. The main shaft 7 is a “rotating member” and the housing 6 is a “fixing member”. The same applies to other embodiments described later.

  The outer rings 2, 2 and the outer ring spacer 4 are, for example, a clearance fit with respect to the housing 6, and are positioned in the axial direction by the step portion 6 a of the housing 6 and the end surface cover 40. The inner rings 3 and 3 and the inner ring spacer 5 are, for example, an interference fit with respect to the main shaft 7 and are positioned in the axial direction by the positioning spacers 41 and 42 on both sides. Note that the positioning spacer 42 on the left side of the figure is fixed by a nut 43 screwed onto the main shaft 7.

The cooling structure will be described.
As shown in FIG. 2, which is a partially enlarged view of FIG. 1, the outer ring spacer 4 includes an outer ring spacer body 11, and ring-shaped lubricating nozzles 12, 12 made of members different from the outer ring spacer body 11. Have The outer ring spacer main body 11 is formed in a substantially T-shaped cross section, and the lubricating nozzles 12 and 12 are fixed to the both sides in the axial direction of the outer ring spacer main body 11 in a symmetrical arrangement. The inner diameter of the outer ring spacer body 11 is larger than the inner diameter of the lubricating nozzles 12 and 12. As a result, a recess 13 is formed on the inner peripheral surface of the outer ring spacer 4, which is composed of the inner peripheral surface of the outer ring spacer main body 11 and the side surfaces of the lubricating nozzles 12, 12 following the inner peripheral surface. Yes. The recess 13 is an annular groove having a rectangular cross section. The inner peripheral surface of the outer ring spacer 4 other than the recess 13, that is, the inner peripheral surfaces of the lubricating nozzles 12 and 12, and the outer peripheral surface of the inner ring spacer 5 are opposed to each other via a minute radial clearance δa. . Thereby, a space 14 having a wider radial width than the others is formed between the recessed portion 13 and the outer peripheral surface of the inner ring spacer 5.

  The outer ring spacer body 11 is provided with a nozzle hole 15 for discharging compressed air A for cooling toward the outer peripheral surface of the inner ring spacer 5. In this example, a plurality of (for example, three) nozzle holes 15 are provided, and each of them is arranged in a uniform manner in the circumferential direction. Each nozzle hole 15 has a shape in which an intermediate portion in the length direction is narrowed to enable supersonic flow. For example, the shape of a Laval nozzle. The outlet of the nozzle hole 15 opens into the recessed portion 13 on the inner peripheral surface of the outer ring spacer 4.

  As shown in FIG. 3, each nozzle hole 15 is inclined forward in the rotational direction of the inner ring spacer 5. That is, the position is offset from an arbitrary radial straight line L in a cross section perpendicular to the axis of the outer ring spacer 4 in a direction orthogonal to the straight line L. The reason why the nozzle hole 15 is offset is to improve the cooling effect by causing the compressed air A to act as a swirling flow in the rotation direction of the inner ring spacer 5. In FIGS. 1 and 2, the outer ring spacer 4 is indicated by a cross section passing through the center line of the nozzle hole 15.

  On the outer peripheral surface of the outer ring spacer main body 11, an introduction groove 16 for introducing the compressed air A into each nozzle hole 15 from the outside of the bearing is formed. The introduction groove 16 is provided in an intermediate portion in the axial direction on the outer peripheral surface of the outer ring spacer 4 and is formed in an arc shape communicating with each nozzle hole 15. The introduction groove 16 is provided on the outer peripheral surface of the outer ring spacer main body 11 over an angular range α indicating most of the circumferential direction except a circumferential position where an air oil supply path (not shown) described later is provided. . As shown in FIG. 1, a compressed air introduction path 45 is provided in the housing 6, and the introduction groove 16 communicates with the compressed air introduction path 45. An air supply device (not shown) for supplying the compressed air A to the compressed air introduction hole 45 is provided outside the housing 5.

  As shown in FIG. 4, a portion (hereinafter referred to as “nozzle hole component”) 20 constituting the nozzle hole 15 in the outer ring spacer body 11 is provided for each nozzle hole 15, and each nozzle hole component 20 is The outer ring spacer main body 11 is formed separately from the other part 11a occupying the most part. In the example of the figure, each nozzle hole constituting portion 20 has a substantially rectangular shape when viewed from the radial direction, but may have another shape. Each of these nozzle hole constituting portions 20 is fixed to the other portion 11a by being fitted into a fitting hole 21 provided in the outer ring spacer body 11 so as to penetrate in the radial direction by press fitting or the like. The introduction groove 16 includes groove portions 16a and 16b formed on the outer peripheral surface of the nozzle hole constituting portion 20 and the other portion 11a, respectively.

  The nozzle hole component 20 is made of, for example, a resin material and is manufactured by injection molding or the like. For this reason, the nozzle hole 15 having a complicated shape with a narrow middle portion in the flow direction of the compressed air A and a non-uniform longitudinal section along the flow direction, such as a Laval nozzle, is also formed with high accuracy and high productivity. be able to. The other part 11a of the outer ring spacer main body 11 and the parts other than the outer ring spacer main body 11 (excluding the cage 9) are made of metal such as bearing steel.

The lubrication structure will be described.
As shown in FIG. 1, the outer ring spacer 4 has the lubricating nozzles 12 and 12 for supplying air oil into the bearing. Each of the lubricating nozzles 12 includes a tip portion 30 that protrudes into the bearing and faces the outer peripheral surface of the inner ring 3 through an air oil passage annular clearance δb. In other words, the tip portion 30 of the lubricating nozzle 12 is disposed so as to enter the bearing so as to cover the outer peripheral surface of the inner ring 3. Further, the tip portion 30 of the lubricating nozzle 12 is disposed radially inward from the inner peripheral surface of the cage 9.

As shown in FIG. 2, the lubricating nozzle 12 is provided with an air oil supply hole 31 for supplying air oil to the annular clearance δb between the lubricating nozzle 12 and the outer peripheral surface of the inner ring 3. The air oil supply hole 31 is inclined so as to reach the inner diameter side toward the bearing side, and an outlet is opened on the inner peripheral side of the tip portion 30. Air oil is supplied to the air oil supply hole 31 through an air oil supply path (not shown) provided in the housing 6 and the outer ring spacer main body 11. An annular recess 3 a is provided at a location on the extended line of the air oil supply hole 31 on the outer peripheral surface of the inner ring 3.
The oil of the air oil discharged from the lubricating nozzle 12 accumulates in the annular recess 3a, and this oil moves to the bearing center side along the outer peripheral surface of the inner ring 3 which is an inclined surface by the centrifugal force accompanying the rotation of the inner ring 3. It is guided.

The exhaust structure will be described.
The bearing device J is provided with an exhaust path 46 for exhausting compressed air for cooling and air oil for lubrication. The exhaust passage 46 includes an exhaust groove 47 provided in a part of the outer ring spacer body 11 in the circumferential direction, a radial exhaust hole 48 provided in the housing 6 and communicating with the exhaust groove 47, and an axial exhaust hole 49. Have The exhaust groove 47 of the outer ring spacer body 11 is formed across a circumferential position diagonal to the position where the air oil supply path is provided.

The effect | action of the cooling structure of the bearing apparatus which consists of the said structure is demonstrated.
By cooling the compressed air A for cooling toward the outer peripheral surface of the inner ring spacer 5 from the nozzle hole 15 provided in the outer ring spacer 4, first, the inner ring spacer 5 is cooled, The inner ring 3 and the main shaft 7 of the rolling bearing 1 are cooled. At that time, the inner ring spacer 5 can be efficiently cooled for the following reason.

The first reason is that the nozzle hole 15 has a shape that enables supersonic flow like a Laval nozzle. The supersonic compressed air A is discharged from the nozzle hole 15 by adjusting the pressure, flow rate and the like of the compressed air A by the air supply device. In the case of the example in the figure, since the compressed air A is discharged into the space 14 between the recess 13 on the inner peripheral surface of the outer ring spacer 4 and the outer peripheral surface of the inner ring spacer 5, the compressed air A in the space 14 is discharged. Expands adiabatically, decreasing in temperature and increasing in volume. As the volume increases, the flow rate further increases. In this way, the inner ring spacer 5 is efficiently cooled by blowing the compressed air A at a low temperature and at a high speed onto the inner ring spacer 5.
If the recess 13 is provided, the compressed air A flows from the space 14 of the recess 13 to the radial clearance δa between the outer ring spacer 4 and the inner ring spacer, which is narrower than the space 14. 5, the flow velocity of each part of the compressed air A flowing along the outer peripheral surface in the circumferential direction is made uniform, and the flow velocity of the compressed air A flowing into the bearing becomes uniform. Thereby, there is also an effect that the collision sound between the compressed air A and the rotating rolling element 9 can be reduced.

  The second reason is that the nozzle hole 15 is inclined forward in the rotational direction of the inner ring spacer 5. Thereby, the compressed air A discharged from the nozzle hole 15 flows in the axial direction while turning along the outer peripheral surface of the inner ring spacer 5, and is discharged to the outside of the bearing through the exhaust path 46. Since the compressed air A turns, the time during which the compressed air A is in contact with the outer peripheral surface of the inner ring spacer 5 is longer than when the straight air flows in the axial direction, and the inner ring spacer 5 can be cooled more efficiently. it can.

  Since the nozzle hole component 20 is made of a resin material or the like, the nozzle hole 15 has a narrow intermediate portion in the flow direction of the compressed air A, such as a Laval nozzle, and the longitudinal section along the flow direction is not uniform. Even so, it can be manufactured with high accuracy and high productivity. It is difficult to machine a nozzle hole whose longitudinal section is not uniform by cutting a metal casting.

  Further, in this embodiment, each nozzle hole 15 is individually provided in the nozzle hole constituting portion 20, and each nozzle hole constituting portion 20 is fitted in the fitting hole 21 provided in the other portion 11 a of the outer ring spacer main body 11. It is configured to include. If the nozzle hole component 20 is common to the nozzle holes 15, the nozzle hole component 20 has an annular shape or a shape close to an annular shape, and the other portion 11a is divided by the nozzle hole component 20 on both sides in the axial direction. Become. In this embodiment, when the nozzle hole component 20 is a resin material, the axial rigidity of the outer ring spacer 4 is small. With the configuration of this embodiment, the nozzle hole component 20 does not divide the other portion 11a on both sides in the axial direction, and can prevent a decrease in the axial rigidity of the outer ring spacer 4.

Hereinafter, different embodiments of the present invention will be described.
In the embodiment shown in FIG. 5, an air hole 33 communicating with the outside of the bearing device is provided in an intermediate portion of the nozzle hole 15 in the flow direction of the compressed air A. In this case, air B is sucked into the nozzle hole 15 from the outside of the bearing device through the air hole 33 due to the negative pressure generated by the dynamic pressure of the compressed air A flowing through the nozzle hole 15. Thereby, the flow rate of the compressed air A discharged from the nozzle hole 15 is increased, and the cooling effect is improved.

  6 shows an example in which the air hole 33 is provided in the nozzle hole 15 having a general shape. As shown in FIG. 5, the air hole 33 is formed in the nozzle hole 15 having a shape capable of generating a supersonic flow. It may be provided. 5 and 6, the air holes 33 are provided, so that the cross-sectional shapes of the nozzle hole constituting portion 20 and the fitting hole 21 are slightly different from those in FIG. 2. The other structure is the same as that of FIG.

  7 to 9 show further different embodiments. The nozzle hole 15 of each of the above embodiments has a non-uniform longitudinal cross section along the flow direction of the compressed air A, whereas the nozzle hole 15 of this embodiment has a cross section perpendicular to the flow direction of the compressed air A. Is a non-uniform shape. That is, in order to improve the cooling efficiency, the cross-sectional shape in the vicinity of the nozzle hole outlet 15a has a flat shape in the axial direction compared to the circumferential size. For example, a rectangular shape elongated in the axial direction as shown in FIG. 9A or an elliptical shape elongated in the axial direction as shown in FIG. Here, the flat shape is not limited to a flat shape whose axial dimension is extremely long compared to the circumferential dimension, and includes a shape whose axial dimension is slightly longer than the circumferential dimension. .

The reason why the cooling efficiency is improved when the cross-sectional shape in the vicinity of the nozzle hole outlet 15a is a flat shape will be described.
As shown in FIG. 8, when a large amount of compressed air A is discharged from the nozzle hole 15 toward the inner ring spacer 5, the flow rate of the compressed air A reaches the maximum speed (for example, sound speed) at the nozzle hole outlet 15a. At this time, when the clearance δa between the nozzle hole outlet 15a and the rotation spacer 5 is narrow and the cross-sectional shape near the nozzle hole outlet 15a is circular, the pressure between the nozzle hole outlet 15a and the inner ring spacer 5 is It tends to be high, and a compression wave is generated near the nozzle hole outlet 15a in the clearance δa. As the supply amount of the compressed air A increases, a stronger compression wave is generated. When the compression wave is generated, the straight flow of the compressed air A discharged from the nozzle hole 15 is inhibited and diffused in the axial direction as shown in FIGS. Thereby, the time for the compressed air A to contact the outer peripheral surface of the inner ring spacer 5 is shortened, and the cooling effect is reduced. FIG. 10 shows the pressure distribution near the outlet of the nozzle hole in a state where the compression wave is generated, and FIG. 11 shows the temperature distribution near the outlet of the nozzle hole in a state where the compression wave is generated.

  When the cross-sectional shape in the vicinity of the nozzle hole outlet 15a is circular, a compression wave is likely to be generated. The amount of compressed air A flowing into the clearance δa between the nozzle hole outlet 15a and the inner ring spacer 5 (mass flow rate). However, as shown in FIG. 12C, this is considered to be locally increased at the central portion in the axial direction, which is an extension of the center of the nozzle hole 15. When the cross-sectional shape in the vicinity of the nozzle hole outlet 15a is a flat shape like the nozzle 15 in FIGS. Since the amount is equalized in the axial direction, strong compression waves are not generated, and the compressed air A can flow smoothly in the circumferential direction without diffusing in the axial direction.

  In the bearing device J of this embodiment, since the outer ring spacer 4 does not have a lubricating nozzle, there is no distinction between the outer ring spacer and the outer ring spacer body. Therefore, each nozzle hole constituting part 20 is formed separately from the other part 4a occupying the most part of the outer ring spacer 4, and is fitted in the fitting hole 21 provided in the other part 4a.

  In each of the above embodiments, the case where the rolling bearing 1 is used for inner ring rotation has been shown, but the present invention can also be applied when used for outer ring rotation. In this case, for example, a shaft (not shown) fitted to the inner circumference of the inner ring 3 is a fixed member, and a roller (not shown) fitted to the outer circumference of the outer ring 2 is a rotating member.

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Outer ring (fixed side ring)
3. Inner ring (rotating raceway)
4. Outer ring spacer (fixed side spacer)
4a ... other part 5 ... inner ring spacer (rotating side spacer)
6 ... Housing (fixing member)
7 ... Spindle (Rotating shaft)
11a ... other part 15 ... nozzle hole 15a ... nozzle hole outlet 20 ... nozzle hole constituent part (part constituting the nozzle hole)
21 ... Fitting hole 33 ... Air hole A ... Compressed air J ... Bearing device

Claims (5)

A stationary spacer and a rotating spacer are provided adjacent to the stationary bearing ring and the rotating bearing ring facing the inside and outside of the rolling bearing, respectively, and the stationary bearing ring and the stationary spacer are fixed members and rotating. In the bearing device installed in the fixed member of the members, the rotating side raceway and the rotating side spacer are installed in the rotating member of the fixed member and the rotating member,
The fixed side spacer is provided with a nozzle hole for discharging compressed air for cooling toward a circumferential surface where the rotary side spacers face each other, and the nozzle hole is formed in the periphery of the fixed side spacer. With respect to the normal passing through the center of the outlet of the nozzle hole on the surface, the part that constitutes the nozzle hole in the fixed side spacer is inclined to the front in the rotation direction of the rotating side spacer and the other part. Separately, the nozzle hole is not uniform in the shape of one or both of a cross section perpendicular to the flow direction of the compressed air and a vertical cross section along the flow direction of the compressed air, and the outlet of the nozzle hole cooling structure of bearings device cross-sectional shape in the vicinity of the axial dimension as compared to the circumferential dimension is long flat shape. A stationary spacer and a rotating spacer are provided adjacent to the stationary bearing ring and the rotating bearing ring facing the inside and outside of the rolling bearing, respectively, and the stationary bearing ring and the stationary spacer are fixed members and rotating. In the bearing device installed in the fixed member of the members, the rotating side raceway and the rotating side spacer are installed in the rotating member of the fixed member and the rotating member,
The fixed side spacer is provided with a nozzle hole for discharging compressed air for cooling toward a circumferential surface where the rotary side spacers face each other, and the nozzle hole is formed in the periphery of the fixed side spacer. With respect to the normal passing through the center of the outlet of the nozzle hole on the surface, the part that constitutes the nozzle hole in the fixed side spacer is inclined to the front in the rotation direction of the rotating side spacer and the other part. Separately, the nozzle hole is not uniform in the shape of one or both of a cross section perpendicular to the flow direction of the compressed air and a vertical cross section along the flow direction of the compressed air. the middle portion in the flow direction of the compressed air, the cooling structure of the shaft receiving apparatus provided with air hole communicating with the bearing device outside. 3. The cooling structure for a bearing device according to claim 1 , wherein the stationary spacer has a plurality of the nozzle holes in a circumferential direction, and each of the portions constituting the nozzle holes individually, A cooling structure for a bearing device fitted in a fitting hole provided in a portion.   The cooling structure of the bearing device according to any one of claims 1 to 3, wherein a longitudinal section of the nozzle hole has a shape having a narrow middle portion in a length direction and capable of supersonic flow. Equipment cooling structure. The cooling structure for a bearing device according to any one of claims 1 to 4 , wherein an annular recess is provided on a peripheral surface of the fixed-side spacers facing each other, and an outlet is provided in the recess. A cooling structure of a bearing device that is opened and provided with the nozzle hole.

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