JP2000296439A - Cooling structure for grease-lubricated rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure for grease-lubricated rolling bearings that is for use in spindle devices and that can efficiently cool the inner ring of rolling bearings without splashing grease sealed in them and thus suppress an increase in the pre-load of the rolling bearings and improve the allowable rotating speed of the spindles. SOLUTION: For an arrangement having grease-lubricated ball bearings 3 supporting a spindle 1 rotatably in a housing 2, and inner ring spacers 5 abutting inner rings 3a of the ball bearings 3 outside of the spindle 1, the cooling structure for the grease-lubricated ball bearings 3 has outlets 10 cut in either of the housing 2 and the spindle 1 to air-cool the inner ring spacers 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease lubricated rolling bearing cooling structure used in a spindle device used in a machine tool or the like.

[0002]

2. Description of the Related Art Generally, a spindle device is configured such that a spindle is supported on a housing via a rolling bearing. Such a spindle device is applied to a machine tool or the like, and is used at a high speed. For this reason, the temperature of the rolling bearing increases due to frictional heat, and the preload increases, and in some cases, the rolling bearing may seize. Therefore, in the use of the spindle device, cooling of the rolling bearing is very important, and various cooling methods have been known.

For example, in oil mist lubrication or oil-air lubrication, lubrication and cooling of a rolling bearing are performed simultaneously by directly blowing compressed air to a rolling bearing together with oil. There is also a method of indirectly cooling the rolling bearing by cooling the housing by passing oil through a spiral groove provided on the outer peripheral surface of the housing.

[0004]

However, in a grease lubricated rolling bearing, there is no cooling effect because the compressed air is not sprayed unlike the oil mist lubrication and the oil air lubrication described above. As a result, the temperature rises and the preload tends to increase. Further, if compressed air is directly blown onto grease-lubricated rolling bearings for cooling, the sealed grease may be scattered and seizure may occur due to poor lubrication.

In the method of oil-cooling the housing, the rolling bearing is indirectly cooled, so that the outer ring is in contact with the housing and thus is efficiently cooled. However, the inner ring is not in contact with the housing, so that it is not so efficient. Not cooled.
As a result, a temperature difference is generated between the outer ring and the inner ring, and a large preload is applied. Therefore, there is a problem that the allowable rotation speed of the spindle is limited, which is not preferable.

Accordingly, the present invention solves the above-mentioned problems of the prior art, and enables the inner ring of a rolling bearing to be efficiently cooled without scattering the encapsulated grease, and as a result, the rolling bearing It is an object of the present invention to provide a grease lubricated rolling bearing cooling structure in a spindle device that suppresses an increase in the preload and improves the allowable rotational speed of the spindle.

[0007]

In order to solve the above problems, the present invention has the following arrangement. That is, the cooling structure of the grease-lubricated rolling bearing of the present invention includes a grease-lubricated rolling bearing that rotatably supports a spindle in a housing, and an inner ring spacer that is in contact with an inner ring of the rolling bearing outside the spindle. Wherein an air outlet for cooling the inner ring spacer is provided in the housing or the spindle.

In the cooling structure for a grease-lubricated rolling bearing of the present invention, an outlet for cooling the inner ring spacer in contact with the inner ring of the rolling bearing is provided in the housing or the spindle, so that gas such as compressed air flows from the outlet. The inner ring of the rolling bearing in contact with the inner ring spacer can be indirectly cooled by spraying the air on the inner ring spacer.
As a result, it is possible to suppress an increase in the preload of the rolling bearing and improve the permissible rotational speed of the spindle.

Further, since the spindle is in contact with the inner ring spacer, the spindle can be indirectly cooled at the same time. Further, when the outlet is provided in the spindle, gas such as compressed air is supplied to the outlet through the inside of the spindle, so that the spindle can be directly cooled. By cooling the spindle together with the rolling bearing, it is possible to suppress an increase in the preload of the rolling bearing from this point, and to further improve the permissible rotational speed of the spindle. Further, the elongation of the spindle from the reference plane is suppressed.

Further, the cooling structure of the grease lubricated rolling bearing of the present invention cools the inner ring of the rolling bearing indirectly by blowing gas to the inner ring spacer without directly blowing gas to the rolling bearing. The grease sealed in the rolling bearing does not scatter, and the rolling bearing does not seize due to poor lubrication. In the present invention, if the inner ring spacer is provided in contact with the inner ring, only the inner ring spacer may be provided, or both the inner ring spacer and the outer ring spacer in contact with the outer ring may be provided. However, when the outlet is provided in the housing and the outer ring spacer is provided, a guide path for guiding the gas from the outlet to the inner ring spacer is provided in the spacer.

The shape of the inner ring spacer used in the present invention is not particularly limited. However, from the point of the present invention that cooling is performed by blowing gas, it is not possible to use a shape having a large surface area and high cooling efficiency. Very good. Preferable shapes include, for example, a shape having a concave portion in a portion where the cooling gas contacts, a shape having a plurality of irregularities, a shape having a cooling fin, and the like. The inner ring can be efficiently cooled by blowing gas onto the concave portion, the cooling fin, and the like.

It is preferable from the viewpoint of cooling efficiency that the portion of the inner ring spacer to which gas is blown is as close as possible to the portion in contact with the inner ring of the rolling bearing.
The material of the inner ring spacer is preferably a material having excellent thermal conductivity for the purpose of the invention. However, it is needless to say that the bearing must have the necessary performance such as strength and heat resistance as a bearing spacer.

Further, when the inner ring spacer and the outer ring spacer are provided, taking into consideration the possibility that the radial clearance between the two spacers may be narrowed due to a load applied to the spindle and brought into contact with the spindle, the seizure resistance is reduced. Good materials may be used.
Examples include copper, carbon, and the like. In the present invention, in order to prevent the gas blown to the inner ring spacer from flowing into the rolling bearing and adversely affecting the sealed grease, an exhaust port and an exhaust path for the gas are provided in the housing or the spindle. Is preferred. The number, size, shape, and the like of the exhaust port and the exhaust path are not particularly limited as long as gas exhaust can be sufficiently performed.

When the outer ring spacer is provided, the cross-sectional area of the exhaust port is made larger than the cross-sectional area of the radial clearance between the inner ring spacer and the outer ring spacer. Further, a guide path for guiding the gas from the inner race spacer to the exhaust port is provided in the outer race spacer. By these things,
The gas is efficiently exhausted, and the gas hardly flows into the rolling bearing.

The gas used for cooling in the present invention is:
The material is not particularly limited as long as the material does not adversely affect the materials such as the spindle, the housing, and the rolling bearing, such as corrosion. Usually, air, nitrogen or the like is used, and the temperature of the gas used is usually room temperature. In addition, the ability to cool the inner race changes depending on the temperature and flow rate of the gas blown to the inner race spacer. Therefore, the temperature and flow rate of the gas are changed according to the conditions such as the rotation speed of the spindle, the type of the rolling bearing, the type of the filled grease, and the desired cooling capacity is set to adjust the temperature of the inner ring.
It is possible to adjust the preload of the rolling bearing. For example, when a fixed-position preload rolling bearing is used, the preload increases during high-speed rotation, but by blowing low-temperature gas onto the inner ring spacer, the temperature is reduced to suppress the increase in preload, and high-speed rotation is reduced. Can be made possible.

The cooling structure of the grease lubricated rolling bearing of the present invention can indirectly cool the spindle in contact with the inner ring as well as the inner ring. A cooling passage may be provided inside the spindle for ventilating the air after cooling the inner ring spacer. As a result, the spindle is efficiently cooled together with the inner race, so that the increase in the preload of the rolling bearing is suppressed, and the permissible rotational speed of the spindle can be further improved. According to this structure, since the gas after air cooling of the inner ring spacer is used for cooling the spindle, there is no need to separately provide an air supply device or the like for cooling the spindle, which is preferable because the cooling structure is simplified.

Further, the cooling structure of the grease lubricated rolling bearing of the present invention cools the rolling bearing by using gas. The gas may be used for the air seal at the front end of the spindle together with the cooling. . The air seal is performed by sending gas to a gas outlet provided at a front end portion of the housing and ejecting the gas from the gas outlet. In that case, the air supply path for supplying gas to the air outlet provided in the housing or the spindle may be connected to the jet port, and gas for cooling the inner ring spacer may be sent to the jet port. Alternatively, the exhaust path may be connected to the jet port, and the gas used for cooling the inner ring spacer may be supplied to the jet port. Further, in order to more efficiently cool the spindle, the cooling path provided inside the spindle and the jet port are connected to send the gas used for cooling the spindle to the jet port. May be.

In any case, there is no need to separately provide an air supply device or an air supply path for the air seal, so that the structure of the spindle device is simplified and preferable. The type of the rolling bearing in the cooling structure of the grease-lubricated rolling bearing of the present invention is not particularly limited, and various rolling bearings such as a deep groove ball bearing, an angular ball bearing, and a cylindrical roller bearing can be adopted. When the spindle is supported by a plurality of rolling bearings, one or more rolling bearings may be used. When two or more types of rolling bearings are supported, the combination of the types is not particularly limited.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling structure for a grease lubricated rolling bearing according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a first embodiment of a cooling structure of a grease lubricated rolling bearing of the present invention, and FIG. 2 is a partial longitudinal sectional view of a main part of FIG.

The spindle 1 is inserted into the housing 2 and
The grease lubricated ball bearings 3 and 3 at the front and the cylindrical roller bearing 4 at the rear thereof are rotatably supported. The ball bearings 3, 3 and the cylindrical roller bearing 4 are fitted on the outer peripheral surface of the spindle 1 and the inner peripheral surface of the housing 2 to
a, 3a, 4a are fixed to the spindle 1 and the respective outer rings 3b, 3b, 4b are fixed to the housing 2.

Between the two ball bearings 3, 3, two inner ring spacers 5, 5 and one outer ring spacer 8 are interposed. The inner ring spacer 5 is in contact with the inner ring 3a, and the outer ring spacer 8 Is in contact with the outer races 3b, 3b. The inner ring spacer 5 includes a cylindrical portion 5a in contact with the spindle 1, a flange portion 5b at an end thereof, and a lip portion 5c contiguous from the outer end of the cylindrical portion 5a in a cylindrical shape. Is formed, and the outer surface of the flange portion 5b is in contact with the inner ring 3a. The outer ring spacer 8 is fitted on the inner peripheral surface of the housing 2.

On the inner peripheral surface of the housing 2 are air outlets 10, 1
0 is provided, and an air supply path 11 that connects the air outlets 10 and an air pump (not shown) is formed inside the housing 2. Further, compressed air fed from the air pump is supplied to the outer ring spacer 8 through the outlets 10 and 1.
Guide paths 12, 12 for guiding from 0 to the recesses 6, 6 are formed.

Further, at the position different from the outlets 10 on the inner peripheral surface of the housing 2, the exhaust ports 20, 20, 2
0, and an exhaust port 2 is provided inside the housing 2.
An exhaust passage 21 is formed to communicate the air outlets 0, 20, 20 and the outside of the housing 2. Further, in the outer race spacer 8, at a position outside the lip portion 5c of the inner race spacer 5 and at a position where the two inner race spacers 5, 5 are in contact with each other, compressed air is discharged from the inner race spacer 5 to the exhaust ports 20, 20,. Guide paths 22, 22, 22 for guiding to 20 are formed in the radial direction.

With such a configuration, the compressed air supplied from the air pump passes through the air supply passage 11 and the air outlets 10,
10 and is guided by guide paths 12, 12 formed in the outer race spacer 8, and is sprayed on the recesses 6, 6 of the inner race spacers 5, 5. Since the concave portions 6 and 6 have a shape having a large surface area and are provided near a portion of the inner ring spacer 5 which is in contact with the inner ring 3a, the inner ring spacers 5 and 5 efficiently cool the inner ring 3a. I do.

The compressed air used for the cooling passes from the concave portion 6, on the one hand, around the tip of the lip portion 5 c, and, on the other hand, passes between the cylindrical portion 5 a and the outer ring spacer 8, on the guide path. The exhaust gas is exhausted from the housing 2 through the exhaust port 20 and the exhaust path 21. In addition, circumferential grooves 14 are formed on the outer peripheral surface of the outer race spacer 8 at positions facing the air outlets 10 so that the outer race spacer 8 is assembled with the housing 2 when the outer race spacer 8 is assembled or operated. The compressed air from the air outlets 10, 10 is always supplied to the guide paths 12, 12 even if they rotate relatively.

The exhaust port 2 on the inner peripheral surface of the housing 2
At positions where 0, 20, and 20 are formed, circumferential grooves 15, 15, and 15 are formed over the entire circumference, and the outer race spacer 8 rotates relative to the housing 2 during assembly or operation. Also, compressed air from the guide paths 22, 22, 22 is always supplied to the exhaust ports 20, 20, 20.

Next, a second embodiment will be described.
FIG. 3 is a partial longitudinal sectional view showing a second embodiment of the grease lubricated rolling bearing cooling structure of the present invention. Here, the air outlet 10 opens toward a circumferential groove 14 provided at the axial center of the outer peripheral surface of the outer ring spacer 8, and the guide path 12 extends radially from the bottom of the peripheral groove 14 between the outer ring. It is also set up on the inner peripheral surface of the seat 8.

An irregular surface 7 having a large number of irregularities is formed on the outer peripheral surface of the cylindrical portion 5a of the inner ring spacer 5. This concave-convex surface 7 has a concave portion formed continuously in a spiral shape,
It is preferable that the concave portion is continuous in the longitudinal direction of the cylindrical portion 5a. Because the compressed air from the outlet 10 is
4. If it reaches the outer periphery of the inner ring spacer 5 via the guideway 12 and reaches the flange portion 5b through the concave portion of the uneven surface 7, it is suitable for cooling the cylindrical portion 5a. The part 5b is also cooled.

The outlet 10 on the inner peripheral surface of the housing 2
Exhaust ports 20, 20 are provided at positions different from the above, and an exhaust path 21 communicating the exhaust ports 20, 20 with the outside of the housing 2 is formed inside the housing 2.
Further, compressed air is supplied to the outer race spacer 8 from the inner race spacer 5 to the exhaust port 2 at a position outside the lip portion 5c of the inner race spacer 5.
Guide paths 22, 22 for guiding to 0, 20 are formed in the radial direction.

With such a structure, compressed air supplied from an air pump (not shown) is sent to the air outlet 10 through the air supply passage 11 and further guided by the guide passage 12 formed in the outer ring spacer 8. And is sprayed on the uneven surface 7 of the inner ring spacers 5. Since the uneven surface 7 has a large surface area, it cools the cylindrical portion 5a efficiently and also cools the flange portion 5b at the same time. Therefore, the inner ring 3a is effectively cooled by these. The compressed air used for cooling bypasses the tip of the lip portion 5c of the inner ring spacer 5 and reaches the guide path 22, from which it passes through the exhaust port 20 and the exhaust path 21 to the outside of the housing 2. Exhausted. The other configuration and operation are the same as those of the first embodiment shown in FIGS. 1 and 2, and therefore, the duplicated description will be omitted.

FIG. 4 is a partial longitudinal sectional view showing a third embodiment of the grease lubricated rolling bearing cooling structure of the present invention. In this embodiment, the outlets 10, 10 are connected to the spindle 1
It is an example in the case of being provided in. That is, at the position on the outer peripheral surface of the spindle 1 that faces the inner race spacers 5, 5, the air outlets 10, 10 facing the inner race spacers 5, 5 are provided.
Inside the spindle 1, an air supply passage 11 communicating with the air outlets 10, 10 is formed. On the upstream side of the air supply passage 11,
It communicates with an air supply chamber 17 formed between the spindle 1 and the end cover 9 of the housing 2, and this air supply chamber 17 is continuous with the discharge side of an air pump (not shown). Since the air supply chamber 17 is formed in a ring shape on the outer periphery of the spindle 1,
During the rotation of the spindle 1, the air supply path 11 is always supplied with air.

On the inner peripheral surface of the cylindrical portion 5a of the inner ring spacer 5, an uneven surface 7 having a large number of unevenness is formed. This concave-convex surface 7 has a concave portion formed continuously in a spiral shape,
It is preferable that the concave portion is continuous in the longitudinal direction of the cylindrical portion 5a. Because the compressed air from the outlet 10 is
4, the inner ring spacer 5 reaches the inner circumference of the inner ring spacer 5, passes through the concave portion of the uneven surface 7, and efficiently cools the inner ring spacer 5 mainly in the area where the uneven surface 7 is formed, and the cooling heat is transmitted to the flange portion 5b. This cools the inner ring 3a.

A guide path 23 is formed between the inner ring spacers 5, 5 in the radial direction. Further, guide paths 22, 22 for guiding the compressed air from the inner ring spacer 5 to the exhaust ports 20, 20 are formed in the outer ring spacer 8 at positions outside the lip portion 5c of the inner ring spacer 5 in the radial direction. . With such a configuration, compressed air supplied from an air pump (not shown) is sent from the air supply chamber 17 to the air outlets 10 and 10 through the air supply passage 11, and the compressed air is supplied to the uneven surfaces 7 and 7 of the inner ring spacers 5 and 5. The inner ring 3a is blown and cooled by the inner ring spacer 5 thus cooled.
To cool. The compressed air used for cooling passes through the guideway 23 between the inner ring spacers 5, 5, passes between the inner ring spacer 5 and the outer ring spacer 8, and further has a lip of the inner ring spacer 5. Part 5
c, leading to the guideway 22 from which the circumferential groove 1
The air is exhausted to the outside of the housing 2 through the exhaust ports 5, 20, the exhaust ports 20, 20, and the exhaust path 21.

Further, in the case of this embodiment, since the air supply passage 11 through which the compressed air is ventilated is formed inside the spindle 1, the spindle 1 is directly cooled by air. Therefore, the spindle 1 is efficiently cooled together with the inner race 3a, and the inner race 3a is cooled by these components. Therefore, an increase in the preload of the ball bearing 3 is suppressed, and the permissible rotational speed of the spindle 1 can be further improved.

In this embodiment, the exhaust port 20 is provided at two places in the axial direction of the housing 2, and this is different from the first embodiment shown in FIGS. Other configurations and operations are the same as those of the first embodiment. The inner peripheral surface of the inner ring spacer 5 may be a smooth cylindrical surface instead of the uneven surface 7. FIG. 5 shows a fourth embodiment, which is different from the second embodiment in which compressed air used for cooling the inner race 3a is exhausted from the exhaust passage 21 of the housing 2 as in the second embodiment. This is an example of a case in which the path is used to cool the spindle 1 and air seal the front end of the spindle 1.

That is, on the outer peripheral surface of the spindle 1, introduction ports 30, 30 are provided at positions facing the inner ring spacers 5, 5, and a circumferential groove extending over the entire circumference is provided at the position where the introduction ports 30, 30 are provided. 16, 16 are formed. Inner ring spacer 5,5
Guide paths 23, 23 for guiding the compressed air used for cooling to the inlets 30, 30 are formed in the radial direction at positions facing the inlets 30, 30. A cooling passage 31 communicating with the inlets 30 is formed inside the spindle 1, and the cooling passage 31 is connected to a spout 40 provided at the front end of the spindle 1. This fume 40
Communicates with an air seal chamber 42 formed between the spindle 1 and the end cover 9 of the housing 2. The air seal chamber 42 is supplied with an amount of air exceeding the amount of leakage from between the end cover 9 and the spindle 1 from the cooling passage 31 and has a high pressure during operation.

With this configuration, the compressed air blown to the uneven surface 7 of the inner race spacers 5 and 5 and used to cool the inner race 3a rips from the uneven surface 7 similarly to the second embodiment. While bypassing the tip of the portion 5c to reach the outer guide path 22 and being exhausted from the exhaust path 21, in the fourth embodiment, the cylindrical section 5a passes through another path, namely, the guide path 23.
And is introduced into the cooling passage 31 from the inlets 30, 30. Then, the spindle 1 is cooled by being ventilated to the cooling passage 31, and is further ejected from the blast port 40 to air seal the front end of the spindle 1.

As a result, the spindle 1 as well as the inner ring 3a are efficiently cooled, the increase in the preload of the ball bearing 3 is suppressed, and the permissible rotational speed of the spindle 1 can be further improved. Further, it is not necessary to separately provide an air supply device for cooling the spindle 1, an air supply device for the air seal, an air supply path, and the like. Other configurations and operations are shown in FIG.
Although the outer peripheral surface of the inner ring spacer 5 is not the concave-convex surface 7 but may be a smooth cylindrical surface as in the first embodiment of FIGS. Good. Further, as the cooling means for the inner ring spacer 5, the shape and structure of the air outlet 10 and the guide path 12 can be the same as those in the first embodiment.

Next, in a fifth embodiment shown in FIG. 6, the compressed air used for cooling the inner ring 3a is supplied by branching the compressed air from the exhaust passage 21 of the second embodiment shown in FIG. This is an example of a case where the air conditioner is used for an air seal at the front end of the spindle 1 via a path 41. A fume port 40 is provided in the end cover 9 of the housing 2, and the fume port 40 and the exhaust path 21 are connected by an air supply path 41. The blowing port 40 faces an air seal chamber 42 formed between the end cover 9 and the spindle 1 as in the fourth embodiment of FIG.
Are kept at high pressure. With such a structure, the compressed air blown to the uneven surface 7 of the inner race spacers 5 and 5 and used for cooling the inner race 3 a passes through the exhaust passage 21 and the housing 2.
While the air is exhausted to the outside, a part of the air is branched from the exhaust path 21 to the air supply path 41, and is ejected from the blast port 40 to maintain the inside of the air seal chamber 42 at a high pressure to air seal the front end of the spindle 1. Thus, there is no need to separately provide an air supply device or the like for an air seal, and it is not necessary to drill a hole in the spindle 1 as in the fourth embodiment shown in FIG.

The outer peripheral surface of the inner ring spacer 5 is not limited to the uneven surface 7, but may be a smooth cylindrical surface as in the first embodiment shown in FIGS. As the cooling means of the inner ring spacer 5, the shapes and structures of the air outlet 10 and the guideway 12 are shown in FIGS.
It can be the same as the first embodiment of FIG.
Other configurations and operations are the same as those of the second embodiment in FIG.

The sixth embodiment shown in FIG. 7 is an example in which compressed air before being blown to the inner ring spacers 5, 5 is used for an air seal at the front end of the spindle 1. This embodiment is similar to the fourth embodiment of FIG. 5 in that an air seal chamber 42 formed between the end cover 9 and the spindle 1 is formed.
In addition, an air supply passage 41 that is continuous with the air supply passage 11 is connected to form an air outlet 40 at the front end of the air supply passage 41. Therefore, before the compressed air supplied from the air pump (not shown) is supplied to the inner ring spacers 5, a part of the compressed air is branched from the air supply path 11 to the air supply path 41, and is ejected from the blast port 40. The front end of the spindle 1 is air-sealed. This allows
There is no need to separately provide an air supply device or the like for the air seal.

The point that the inner ring 3a of the ball bearing 3 is cooled by the compressed air blown out from the outlet 10 through the air supply passage 11 and the air is exhausted from the exhaust passage 21 and other structures and operations are as follows. This is the same as the second embodiment of FIG. However, the outer peripheral surface of the inner ring spacer 5 is not the uneven surface 7,
It may be a smooth cylindrical surface as in the first embodiment of FIGS. Further, as the cooling means for the inner ring spacer 5, the shape and structure of the air outlet 10 and the guide path 12 can be the same as those in the first embodiment.

In each of the embodiments described above, an example is shown in which the cooling structure of the grease lubricated rolling bearing of the present invention is applied to the cooling of the ball bearings 3, 3. Is of course applicable as well. Further, together with the cooling structure of each embodiment, a cooling structure mainly for the outer ring 3b, such as oil cooling of the housing 2, may be adopted. By doing so, the inner and outer rings 3a, 3b can be uniformly cooled.

[0044]

As described above, the cooling structure for a grease-lubricated rolling bearing of the present invention is characterized in that the inner ring spacer that is in contact with the inner ring of the rolling bearing is air-cooled, so that the rolling bearing that is in contact with the inner ring spacer is cooled. The inner ring can be cooled indirectly. As a result, it is possible to suppress an increase in the preload of the rolling bearing and improve the permissible rotational speed of the spindle.

Since the spindle is in contact with the inner ring spacer, the spindle can be indirectly cooled at the same time. Further, when the air outlet is provided in the spindle, the spindle can be directly cooled.Therefore, from this point, an increase in the preload of the rolling bearing is suppressed, and the allowable rotation speed of the spindle is reduced. It is possible to further improve. Further, the elongation of the spindle from the reference plane is suppressed.

Further, in the present invention, since the gas is not directly blown to the rolling bearing, but the gas is blown to the inner ring spacer to indirectly cool the inner ring of the rolling bearing, the grease sealed in the rolling bearing can be used. It does not scatter and the rolling bearing does not seize due to poor lubrication.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a cooling structure of a grease lubricated rolling bearing of the present invention.

FIG. 2 is a partial longitudinal sectional view showing a first embodiment of a cooling structure of a grease lubricated rolling bearing of the present invention.

FIG. 3 is a partial longitudinal sectional view showing a second embodiment of the cooling structure of the grease lubricated rolling bearing of the present invention.

FIG. 4 is a partial longitudinal sectional view showing a third embodiment of the cooling structure of the grease-lubricated rolling bearing of the present invention.

FIG. 5 is a partial longitudinal sectional view showing a fourth embodiment of the cooling structure of the grease-lubricated rolling bearing of the present invention.

FIG. 6 is a partial longitudinal sectional view showing a fifth embodiment of the cooling structure of the grease-lubricated rolling bearing of the present invention.

FIG. 7 is a partial longitudinal sectional view showing a sixth embodiment of the cooling structure of the grease lubricated rolling bearing of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle 2 Housing 3 Ball bearing 3a Inner ring 3b Outer ring 5 Inner ring spacer 5a Cylindrical part 5b Flange part 5c Lip part 6 Concave part 7 Uneven surface 8 Outer ring spacer 10 Blow-out port 11 Air supply path 12 Guide path

Claims (1)

[Claims] 1. A structure comprising: a grease lubricated rolling bearing rotatably supporting a spindle in a housing; and an inner race spacer in contact with an inner race of the rolling bearing outside the spindle, wherein the inner race spacer is air-cooled. A grease-lubricated rolling bearing cooling structure, wherein an air outlet is provided in the housing or the spindle.