JP2009063096A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing having highly reliable sealing performance and enabling to directly measure a slide-contact condition between a seal lip and a seal member from outside of the bearing, in its assembled state. <P>SOLUTION: A seal mechanism has a first seal member 80 fixed to a rotating ring 16 and a second seal member 90 fixed to a static ring 14 opposite to the first seal member in the thrust direction. At least one of the first seal member and the second seal member is provided with an annular seal lip 98 made of an elastic member and extended to the other seal member and brought in slide-contact with the other seal member. In the second seal member, a measurement hole Hs is formed, penetrating the second seal member, along the thrust direction so as to directly measure the slide-contact condition of the seal lip from outside of the bearing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rolling bearing including a stationary wheel maintained in a non-rotating state and a rotating wheel that rotates to face the stationary wheel, particularly for preventing foreign matter from entering the bearing from the outside of the bearing. The present invention relates to an improved sealing mechanism.

Conventionally, various multistage rolling mills are known as rolling equipment for producing steel materials. As an example, the multi-stage rolling mill shown in FIGS. 7A and 7B is provided with a plurality of types of rolling roll groups in the housing 2, and a steel material (not shown) inserted from the insertion port 2a. ) Is rolled to a uniform thickness by a group of rolling rolls while being conveyed along the pass line 2P, and then discharged from the discharge port 2b.
Here, the rolling roll group includes a pair of work rolls 4 for rolling the steel material, a plurality of first intermediate rolls 6 that rotatably support the pair of work rolls 4, and the first intermediate rolls 6 that are rotatable. A plurality of second intermediate rolls 8 to be supported are provided, and each second intermediate roll 8 is rotatably supported by each rolling bearing 12 assembled to a plurality of backing roll shafts 10. Each backing roll shaft 10 is always kept stationary (non-rotating state).

  As shown in FIG. 8, the rolling bearing 12 includes an inner ring (stationary wheel) 14 fitted (fixed) to the backing roll shaft 10, and an outer ring (rotation ring) disposed so as to face the inner ring (stationary wheel) 14. (Rotating wheel) 16, a plurality of rolling elements (cylindrical rollers) 18 assembled in a double row between the inner and outer rings 14, 16, and a cage 20 that holds each rolling element 18 one by one at equal intervals. Yes. Thereby, the rolling bearing 12 has comprised the bearing structure of outer ring | wheel rotation. In the illustrated example, the outer ring 16 has a form having a middle collar, and a lubricating oil or lubricating oil and compressed air are used to lubricate the bearing from a lubricating oil supply hole 54 provided in the inner ring 14. Format.

In such a multistage rolling mill, as shown in FIGS. 7 and 8, the outer ring (rotating ring) 16 of the rolling bearing 12 is in pressure contact with the plurality of second intermediate rolls 8, and the second intermediate roll 8 And is positioned so as to be rotatable. In this case, the pressure of each outer ring 16 acts on the pair of work rolls 4 from the second intermediate roll 8 through the first intermediate roll 6, thereby preventing the work roll 4 from being bent. Thereby, the steel material conveyed along the pass line 2 </ b> P is rolled to a uniform thickness by the pair of work rolls 4.
In addition, as a material of the inner / outer rings 14, 16 and the rolling elements 18, for example, a steel material such as alloy steel can be used.

The rolling bearing 12 is provided with a sealing mechanism for sealing the inside of the bearing from the outside of the bearing in order to prevent intrusion of foreign matters (for example, dust, rolling oil) from the outside of the bearing to the inside of the bearing.
Further, in this case, in order to support the flow of the lubricating oil supplied into the bearing, compressed air is sent from a lubricating oil supply source (not shown) to the lubricating oil supply hole 54, and the compressed air, together with the lubricating oil, After being supplied to the inside of the bearing through the lubricating oil path and the lubricating oil supply hole 54, the sealing mechanism is reached through between the double row rolling elements 18.

"Prior art 1"
FIG. 8 shows an example of a sealing mechanism, which is provided between the inner and outer rings 14 and 16 on both sides of the double row rolling elements 18 (Non-Patent Document 1).

The sealing mechanism shown in FIG. 8 has an annular shield 22 having an inner diameter 22e fixed (press-fit) to the inner ring (stationary ring) 14 and an outer diameter 22t positioned in a non-contact state with respect to the outer ring (rotating ring) 16. And an annular seal 24 disposed inside the bearing relative to the shield 22.
Here, the seal 24 has an outer diameter 24 e fixed to the outer ring (rotating ring) 16 and an inner diameter 24 t extending toward the inner ring (stationary ring) 14, and an extending end (seal lip) extends from the inner diameter 24 t to the shield 22. It is inclined in the direction and positioned so as to be in sliding contact with the shield 22.

  In this case, the seal 24 is formed by covering the core metal 24a with the rubber material 24b, and a rubber lip Lp protruding in a substantially V shape toward the shield 22 is integrally formed on the inner diameter 24t thereof. The lip Lp is always in sliding contact with the shield 22. The outer diameter 24 e of the seal 24 is fitted and fixed to the outer ring (rotating ring) 16 by an annular retaining ring 26.

  By the way, the sealing performance of the sealing mechanism is determined by whether or not the seal lip is in sliding contact with the seal member in the thrust direction. In the above-mentioned prior art document 1 (Non-patent document 1), a certain sealing performance can be maintained by having a predetermined amount of interference in the thrust direction between the lip Lp and the shield 22. However, in the assembled state of the bearing, the sliding contact state between the seal lip and the seal member cannot be directly measured from the outside of the bearing. Therefore, it is necessary to determine how much interference the sealing mechanism is set before using the bearing. Cannot be grasped in advance.

  For this reason, for example, even if the interference force is too weak and the sealing performance is insufficient, it may be used as it is because it cannot be confirmed in advance. If this happens, foreign matter (e.g. dust, water, etc.) can easily enter the bearing, or lubricant (e.g. grease, oil) can easily leak outside the bearing, resulting in early deterioration of the bearing, Alternatively, it may be difficult to maintain a constant rotational performance over a long period of time. Further, for example, even if the interference force is too strong, it cannot be confirmed in advance, and may be used as it is. In this case, the flow of compressed air that supports the conveyance of the lubricant is stopped, and as a result, it may be difficult to maintain the lubrication performance of the bearing constant over a long period of time. In such a case, it is impossible to stably provide a highly reliable bearing with respect to sealing performance.

Therefore, in order to avoid the problems as described above, for example, the dimensions of the location where the seal member is fixed, the dimensions of the seal member, the axial internal clearance of the bearing, and the like are measured. Although measures to calculate the amount of interference with the seal member are conceivable, the labor and time required for this are required, so that the manufacturing efficiency of the bearing is reduced and the manufacturing cost of the bearing is increased.
Product catalog (JTEKT Corporation product catalog Multi-stage rolling mill Cylindrical roller bearing for backup roll CAT.NO.246 P5 Figure 4)

  The present invention has been made in order to solve such problems, and its purpose is to provide a seal capable of directly measuring the sliding contact state between the seal lip and the seal member from the outside of the bearing when the bearing is assembled. The object is to provide a rolling bearing with high reliability in terms of performance.

In order to achieve such an object, the first invention includes a stationary wheel (for example, an inner ring) maintained in a non-rotating state, a rotating wheel (for example, an outer ring) that rotates opposite to the stationary wheel, and a stationary wheel, A plurality of rolling elements (for example, cylindrical rollers) that are rotatably integrated with the rotating wheel, and a sealing mechanism for sealing the inside of the bearing defined between the stationary wheel and the rotating wheel from the outside of the bearing. A rolling bearing provided with a first sealing member fixed to the rotating wheel, and a second sealing member fixed to the stationary wheel facing the first sealing member in the thrust direction. And at least one of the first seal member and the second seal member extends toward the mating seal member and is made of an elastic member that is in sliding contact with the mating seal member. A seal lip is provided and the second seal member Is that the measuring hole to measure directly the sliding contact state of the seal lip from the bearing outside is a rolling bearing, characterized in that it is formed through along the axial direction.
According to the first invention, since the measurement hole is formed in the second seal member, the sliding contact state between the seal lip and the seal member can be directly measured from the outside of the bearing in the assembled state of the bearing. it can. As a result, it is possible to know in advance the amount of interference that the sealing mechanism built into the bearing is set before using the bearing, and as a result, it is possible to stabilize a highly reliable bearing with respect to sealing performance. Can be provided.

According to a second aspect, in the first aspect, the first seal member is disposed in the bearing inner direction with respect to the second seal member, and the annular seal lip is provided on the fixed side of the first seal member. The rolling bearing is characterized by being inclined toward the direction.
According to the second aspect of the invention, the seal lip is provided on the first seal member that is fixed and provided on the fixed ring side so as to incline outward, so that foreign matter, rolling oil, and the like can enter from the outside of the bearing. Can be prevented.
Further, by adopting such a seal lip configuration, if the bearing internal pressure becomes higher than the sum of the rigidity of the seal lip and the bearing external pressure, the seal lip is opened by the bearing internal pressure and the lubricating oil and air are discharged. Therefore, it is possible to create a flow of lubricating oil supplied into the bearing without providing a recovery hole or exhaust hole in the inner ring or the sealing mechanism. Lubrication failure can be prevented. In addition, since no exhaust hole is provided, it is possible to prevent foreign matter or rolling oil from entering through the exhaust hole, which can contribute to early damage of the bearing.

According to a third aspect, in the first aspect, the stationary wheel is configured as an inner ring disposed to face the inner side of the rotating wheel, and the rotating wheel is configured as an outer ring disposed to face the outer side of the inner ring. This is a rolling bearing characterized by this.
According to the third aspect of the invention, it is possible to configure an outer ring rotary rolling bearing in which the inner ring does not rotate and the outer ring rotates.

According to a fourth aspect of the present invention, there is provided a rolling bearing characterized in that in the first aspect of the invention, lubrication is performed inside the bearing using lubricating oil or lubricating oil and compressed air.
According to the fourth aspect of the invention, the inside of the bearing is in a lubricating oil supply state. However, since the inner ring and the sealing mechanism are not provided with a recovery hole or an exhaust hole, the load resistance is not deteriorated, and the seal lip is not provided. There are no restrictions.

5th invention is the rolling bearing used for the multistage rolling mill which rolls steel materials in 1st invention, Comprising: A multistage rolling mill is provided with the rolling roller group for rolling steel materials. The rolling bearing is a rolling bearing characterized by being assembled to a backing roll shaft of a group of rolling rollers.
According to the fifth aspect, it is possible to provide a sealing mechanism suitable for the bearing structure of the backing roll shaft in a simple and inexpensive manner.

  According to the present invention, in a state where the bearing is assembled, a rolling bearing with high reliability can be realized with respect to sealing performance capable of directly measuring the sliding contact state between the seal lip and the seal member from the outside of the bearing.

Hereinafter, a rolling bearing according to an embodiment of the present invention will be described with reference to the accompanying drawings.
1 and 2 show the first embodiment, FIG. 3 shows the second embodiment, FIG. 4 shows the third embodiment, FIG. 5 shows the fourth embodiment, and FIG.
Each of the embodiments is an improvement of the sealing mechanism of the rolling bearing 12 (FIG. 8) used in the multi-stage rolling mill shown in FIG. 7, and therefore only the improved part will be described below. In this case, with respect to the same configuration as the rolling bearing 12 disclosed in FIG. 8 described above, the same reference numerals as those used in the configuration are attached to the drawings used in the present embodiment to explain the configuration. Omitted. That is, in this embodiment, for example, in order to support the flow of the lubricating oil supplied into the bearing, compressed air is sent together with the lubricating oil from a lubricating oil supply source (not shown) to the lubricating oil supply hole 54, and the compression The air employs a lubrication configuration in which the air is supplied together with the lubricating oil through the lubricating oil path and the lubricating oil supply hole 54 and then reaches the sealing mechanism through the two rows of rolling elements 18.
Of course, the case where only the lubricating oil is supplied without compressed air is also within the scope of the present invention.
In the rolling bearing of the present embodiment, the lubricating oil recovery hole is not provided in the inner ring 14, and the compressed air discharge hole is not provided in the sealing mechanism.
Furthermore, in this embodiment, as an application example of the rolling bearing of the present invention, the multi-stage rolling mill shown in FIG. 7 is used as described above, but the rolling bearing of the present invention is limited to this multi-stage rolling mill. However, the design can be changed within the scope of the present invention. In the present embodiment, the inner ring 14 is described as a stationary wheel and the outer ring 16 is a rotating wheel. However, it is within the scope of the present invention to apply the inner ring 14 as a rotating wheel and the outer ring 16 as a stationary wheel.

  The sealing mechanism of the present embodiment shown in FIGS. 1 and 2 includes a first seal member 80 that is fixed to the outer ring 16 as a rotating wheel and a second seal member that is fixed to the inner ring 14 as a stationary ring. And a seal member 90.

The first seal member 80 has a continuous outer diameter 82b together with an annular cored bar 82 provided in non-contact with the inner ring 14 and the entire region of the bearing inner side surface 82a of the cored bar 82. A shield including an annular portion 87 composed of an elastic member 84 to be covered is press-fitted by fitting the outer diameter 82b side to the inner diameter surface of the outer ring 16, and is disposed inward in the axial direction of the bearing. The elastic member 84 protrudes slightly toward the inner ring 14 from the inner diameter of the cored bar 82 and is provided in non-contact with the inner ring 14. Therefore, the surface portion 82c on the bearing outer side of the cored bar 82 is not covered with the elastic member 84 and the cored bar 82 is exposed.
In the figure, 86 is a retaining ring for fixing the first seal member 80.

The second seal member 90 is a cylindrical portion 92 a fitted to the outer diameter surface of the inner ring 14, and a circular plate that extends radially from the cylindrical portion 92 a toward the outer ring 16 and is not in contact with the outer ring 16. A core metal 92 having a substantially L-shaped cross-sectional view composed of a portion 92b, an entire area of the outer diameter surface 92c of the cylindrical portion 92a of the core metal 92, and an entire area of the surface portion 92d on the bearing inward side of the disk portion 92b. The annular member 96 that is formed by the elastic member 94 that continuously covers the outer diameter 92e and the elastic member 94 that covers the surface 92d on the inner side of the bearing of the disk member 92b are integrally extended. The contact seal is constituted by a seal lip 98 that is in sliding contact with the first seal member 80 (also referred to as a V-type seal or a Y-type seal from the shape of the seal).
Then, the inner diameter surface of the cylindrical portion 92 a is fitted into the outer diameter surface of the inner ring 14 and press-fitted, and is disposed outward in the axial direction of the bearing so as to face the annular portion 87 of the first seal member 80. .

The seal lip 98 is a bearing of the cored bar 82 in the first seal member 80 from a predetermined region of the elastic member 94 that covers the inner surface 92d of the disk portion 92b of the elastic member 94 constituting the annular portion 96. The first seal member 80 is integrally extended in an inclined shape (inclined outward) toward the outer surface portion 82c, and is slidably contacted with the rotation of the outer ring 16, thereby forming a contact seal region. An annular seal lip.
Specifically, according to the present embodiment, from the substantially central position in the radial direction between the inner diameter and the outer diameter of the disk portion 92b, the wall portion is thinner than the branch portion 98a through the thick cylindrical branch portion 98a. An overall conical shape having a substantially V-shaped cross-sectional view inclined toward the outer diameter 82b direction which is the fixed side of the first seal member 80 (the large diameter D1 side is opposed to the first seal member 80 direction) The seal lip has a shape that is
The size of the seal lip 98, the position of the seal lip 98, and the size of the contact area are not particularly limited and can be changed within the scope of the present invention according to specifications. For example, the seal lip 98 can be made large to have a long structure with low rigidity.

  In the sealing mechanism of the present embodiment, the second seal member 90 has a measurement hole Hs in the thrust direction for directly measuring the sliding contact state of the seal lip 98 with respect to the first seal member 80 from the outside of the bearing. It is formed to penetrate along. Specifically, the measurement hole Hs is formed so as to penetrate the annular portion 96 (core metal 92, elastic member 94) in the thrust direction in a region closer to the outer diameter 92e than the branch portion 98a.

  As described above, since the measurement hole Hs is formed through the second seal member 90 as in the present embodiment, the sliding contact state between the seal lip 98 and the first seal member 80 can be maintained in the assembled state of the bearing. Measurements can be made directly from the outside of the bearing. Here, as an example of the measurement method, the natural length α of the seal lip 98 in the thrust direction and the thickness β of the second seal member 90 in the thrust direction are measured in advance. Then, by measuring the length γ from the bearing outer end of the measurement hole Hs to the first seal member 80 in a state where the bearing is assembled, and executing the calculation process of (α + β) −γ, the seal lip 98 and The amount of interference with the first seal member 80 can be calculated. In the measurement of the length γ, it is only necessary to actually insert a measuring element of an existing measuring device from the measuring hole Hs. However, since a wide variety of measuring devices can be applied, particularly here, Not limited.

Thereby, it is possible to grasp in advance before use of the bearing how much the interference mechanism is set. For this reason, even if, for example, the interference force is too weak and the sealing performance is insufficient as in the prior art, it is not used as it is without confirming it in advance. As a result, it is possible to prevent foreign matters (for example, dust, water, etc.) from entering the inside of the bearing and lubricant (for example, grease, oil) to leak outside the bearing. As a result, not only can the early deterioration of the bearing be prevented, but also the rotational performance of the bearing can be maintained constant over a long period of time. For example, even if the interference force is too strong, it is not used as it is without confirming it in advance. Thereby, the flow of the compressed air that supports the conveyance of the lubricant can be maintained in an optimum state. As a result, the lubricating performance of the bearing can be kept constant over a long period of time. Therefore, it is possible to stably provide a highly reliable bearing with respect to sealing performance.
Furthermore, the above-mentioned effect can be realized only by penetrating and forming the measurement hole Hs in the second seal member 90, and the manufacturing efficiency of the bearing can be improved because it does not take time and effort required for it. The manufacturing cost of the bearing can be greatly reduced.

  In the above-described embodiment, the shape and size of the measurement hole Hs are not particularly mentioned, but these are arbitrarily set according to the shape and size of an existing measuring instrument inserted into the measurement hole Hs. Therefore, although not particularly limited here, it is possible to apply various shapes such as a triangular shape, a square shape, or a circular shape.

Further, by being configured as in the present embodiment, the sealing mechanism can particularly prevent intrusion of foreign matter, rolling oil, and the like from the outside of the bearing.
In addition, with such a sealing mechanism, the bearing internal pressure is the sum of the rigidity of the seal lip 98 and the bearing external pressure in a type in which lubrication is performed using lubricating oil or lubricating oil and compressed air as in this embodiment. If higher, the seal lip 98 is opened by the bearing internal pressure, and the lubricating oil and air are discharged. Accordingly, it is possible to create a flow of lubricating oil supplied into the bearing without providing a recovery hole or an exhaust hole in the inner ring 14 or the sealing mechanism, thereby preventing poor lubrication inside the bearing and in the seal lip 98 region. . In addition, since no exhaust hole is provided, it is possible to prevent foreign matter or rolling oil from entering through the exhaust hole, which can contribute to early damage of the bearing.
According to the present embodiment, the second seal member 90 disposed on the inner ring 14 is provided with the seal lip 98 that slides on the first seal member 80 that rotates together with the outer ring 16 to form a seal region of contact. Therefore, there is no problem that the sealing lip forming the contact sealing region as in the prior art is opened by the centrifugal force and the sealing performance is deteriorated.
In addition, since the seal lip 98 is integrally provided in a predetermined region of the elastic member 94 integrally forming the second seal member 90, the process of incorporating the seal mechanism is simple, and the seal mechanism inside the bearing is It is possible to save the installation area.
Further, according to the present embodiment, the inside of the bearing is in a lubricating oil supply state. However, since the inner ring 14 and the sealing mechanism are not provided with a recovery hole or an exhaust hole, the load resistance is not deteriorated and the seal is sealed. There are no restrictions on the lip 98. That is, the seal lip 98 may be in contact (sliding contact) as long as it is a surface portion 82c on the bearing outer side of the metal core 82 of the first seal member 80, and the adjustment of the lip opening pressure of the seal is easy. .

FIG. 3 is a schematic sectional view showing a part of the rolling bearing according to the second embodiment of the present invention.
In this embodiment, in the above-described rolling bearing sealing mechanism (FIG. 8), the shield 22 as the second seal member is slid on the seal lip Lp protruding from the first seal member (seal 24) with respect to the shield 22. This is a type in which a measurement hole Hs for directly measuring the contact state from the outside of the bearing is formed so as to penetrate along the thrust direction. Since the other configuration is the same as the bearing configuration of FIG. 8, the description thereof is omitted.
Moreover, since the effect of a present Example is the same as that of Example 1 mentioned above, the description is abbreviate | omitted.

FIG. 4 is a schematic sectional view showing a part of the rolling bearing according to the third embodiment of the present invention.
The present embodiment is an embodiment in which a floating ring 100 is provided between double-row cylindrical rollers, and the sealing mechanism of the present invention is applied to the sealing mechanism. This is a form in which a measurement hole Hs for directly measuring the sliding contact state of the seal lip 98 with respect to the first seal member 80 from the outside of the bearing is formed penetrating along the thrust direction.
The floating ring 100 cooperates with the inner ring collars 14a and 14a and the outer ring collar 16a to restrict the axial movement of the rolling elements (cylindrical rollers) 18 in each row and to prevent the rolling elements (cylindrical rollers) 18 from skewing. This is a well-known configuration to prevent.
Since other configurations and operational effects are the same as those of the first embodiment, description thereof is omitted.

FIG. 5 is a schematic sectional view showing a part of the rolling bearing according to the fourth embodiment of the present invention.
In the present embodiment, the sealing mechanism of the present invention is applied to an example in which the outer collar 14a of the inner ring 14 is a separate part. In the sealing mechanism, the second seal member 90 is connected to the first seal member 80. This is a type in which a measurement hole Hs for directly measuring the sliding contact state of the seal lip 98 from the outside of the bearing is penetrated along the thrust direction.
5A shows a type in which the lubricating oil supply hole 54 is provided in the inner ring, and FIG. 5B shows a spacer 102 between the inner rings 14 and 14 and a floating ring between the rolling elements (cylindrical rollers) 18 and 18. 1 is an embodiment including 100.
Since other configurations and operational effects are the same as those of the first embodiment, description thereof is omitted.

FIG. 6 is a schematic cross-sectional view showing a partially omitted rolling bearing according to Embodiment 5 of the present invention.
In the present embodiment, the sealing mechanism of the present invention is applied to a double-row tapered roller bearing incorporating a double-row tapered roller as the rolling element 18, and the second seal member 90 is sealed against the first seal member 80. This is a form in which a measurement hole Hs for directly measuring the sliding contact state of the lip 98 from the outside of the bearing is formed so as to penetrate along the thrust direction.
Since other configurations and operational effects are the same as those of the first embodiment, description thereof is omitted.
"Modification 1"

In each of the above-described embodiments, the seal lips 98 and Lp have a single configuration. For example, the first seal member 80 includes a plurality of lips that come into contact with the surface portion 82c on the bearing outer side of the cored bar 82. However, it is within the scope of the present invention. The plurality of lips may be branched from the seal lip 98 of the present embodiment, or may protrude from a predetermined region of the elastic member 94 separately from the seal lip 98 of the present embodiment. Good, but care must be taken to ensure that the torque is not too high.
"Modification 2"

In Examples 1 to 4 shown in FIGS. 1 to 5 described above, a “cylindrical roller” is illustrated as the rolling element 18, and in Example 5 illustrated in FIG. 6, “conical roller” is illustrated as the rolling element 18. However, the same effect can be obtained even if other rolling element forms such as “balls” are applied. Further, in each of the embodiments described above, the bearing structure is provided with the rolling elements 18 in two rows in the axial direction. However, the same effect can be obtained by using one row or three or more rows in the axial direction.
“Modification 3”

Foreign materials such as metal chips, shavings, burrs, and wear powder may be mixed in the bearing lubricant, and these foreign materials may damage the races and rolling elements, resulting in a significant decrease in bearing life. You may be invited. The inner and outer rings 14 and 16 and the rolling elements 18 can be formed of a steel material such as alloy steel as in the conventional case. However, since the inner ring 14 does not rotate with the shaft 10, The load applied to the inner ring 14 is always applied in the same phase with respect to the applied radial load. Therefore, the inner ring 14 has a fatigue life earlier than the outer ring 16 and the rolling elements 18. That is, there is also a problem that the life is likely to be shortened due to damage caused by foreign matter.
Therefore, the inner ring as a stationary ring is preferably configured as follows.
That is, for example, for example, an alloy mainly containing carbon (C); 0.1 to 1.2% by weight, chromium (Cr); 1 to 3% by weight, and further containing 2.0% by weight or less of molybdenum (Mo). Made of steel, carburized or carbonitrided to form a surface layer (also called rolling surface layer), the amount of retained austenite (γR vol%) of the surface layer is 20 to 45 vol%, fine carbide or carbonitride The average particle size is 2.3 μm or less.
Moreover, it is preferable that the average particle diameter of a fine carbide | carbonized_material or a carbonitride shall be 0.5-1.5 micrometers, for example.
The surface hardness (Hv) of the surface layer is in the range of −4.7 × (γR vol%) + 920 ≦ Hv ≦ −4.7 × (γR vol%) + 1020 with respect to the amount of retained austenite (γR vol%). Is preferred.
Further, the molybdenum (Mo) content is preferably 1/3 or more of the chromium (Cr) content.
By configuring the inner ring 14 in this way, an effect that the life of the inner ring 14 can be extended is obtained.
“Modification 4”

Further, in this embodiment, the disk portion 92b of the cored bar 92 in the second seal member 90 has a flat shape, but the concave portion and the convex portion (not shown) continuous in the circumferential direction have the same axial center. It is also possible to construct a side-view wave shape by being arranged in concentric circles within the scope of the present invention. By configuring in this manner, the strength of the cored bar 92 can be improved, and deformation at the time of press-fitting into the inner ring 14 can be prevented. Accordingly, it is possible to prevent a problem that the seal lip 98 strikes the first seal member 80 too much due to the deformation of the metal core 92, or the seal lip 98 does not hit the first seal member 80 and the contact seal area is not formed. be able to. As a result, the bearing can be prevented from early seizure due to poor lubrication or contamination, and the life of the bearing can be improved.
Moreover, this uneven | corrugated structure may be the form which each concave part and convex part are not comprised circularly but meandered. Further, the concave portion and the convex portion may have different sizes (depth, height, width, etc.). Furthermore, the concave portion and the convex portion may be provided intermittently.
"Modification 5"

  Further, in the drawings of the above-described embodiments, the measurement hole Hs formed by drilling the second seal member is shown, but the measurement is performed by inserting the probe of the measuring device into contact with the first seal member. If possible, the second sealing member may be partially cut away to form the measurement hole Hs.

It is sectional drawing which abbreviate | omits and shows a part of Example 1 which is one Embodiment of this invention rolling bearing while expanding. It is sectional drawing which expands and shows the structural part of the sealing mechanism of FIG. It is sectional drawing which abbreviate | omits and shows an enlarged view of Example 2, (a) is sectional drawing which abbreviate | omits and shows a structure of a rolling bearing partially, (b) is sealing of (a) It is sectional drawing which expands and shows the structural part of a mechanism. It is sectional drawing which abbreviate | omits and shows a part of Example 3 expanded. FIG. 6 is a cross-sectional view showing a part of the fourth embodiment omitted and enlarged, in which (a) shows a form in which the outer collar of the inner ring is a separate collar ring and the sealing mechanism constituting the present invention is incorporated in the collar ring. , (B) is an embodiment in which the inner collar of the outer ring is eliminated, a floating ring is installed between the rollers, the outer collar of the inner ring is a separate collar, and the sealing mechanism constituting the present invention is incorporated in the collar ring. It is. It is sectional drawing which abbreviate | omits and shows an enlarged view of Example 5, and is one Embodiment which applied this invention to the double row tapered roller bearing. In one application example of the rolling bearing of the present invention, (a) is a schematic side view showing a configuration example of a rolling roll group of a multi-stage rolling mill, and (b) is a schematic front view showing a configuration example around a backing roll axis. is there. It is sectional drawing of the rolling bearing which concerns on the prior art 1, (a) is sectional drawing which abbreviate | omits and shows the structure of the conventional rolling bearing incorporated in the backing roll axis | shaft partially, (b) is ( It is sectional drawing which expands and shows the structural part of the sealing mechanism of a).

Explanation of symbols

14 Inner ring (stationary wheel)
16 Outer ring (rotating wheel)
18 Rolling element 80 First seal member 82 Core metal 84 Elastic member 87 Ring portion 90 Second seal member 92 Core metal 94 Elastic member 96 Ring portion 98 Seal lip Hs Measurement hole

Claims (5)

A stationary wheel maintained in a non-rotating state, a rotating wheel that rotates opposite to the stationary wheel, a plurality of rolling elements that are rotatably incorporated between the stationary wheel and the rotating wheel, and a stationary wheel and a rotating wheel A rolling bearing provided with a sealing mechanism for sealing the inside of the bearing partitioned from the outside of the bearing,
The sealing mechanism includes a first seal member fixed to the rotating wheel, and a second seal member fixed to the stationary wheel so as to face the first seal member in the thrust direction.
At least one of the first seal member and the second seal member is provided with an annular seal lip made of an elastic member extending toward the mating seal member and in sliding contact with the mating seal member. And
A rolling bearing characterized in that a measurement hole for directly measuring the sliding contact state of the seal lip from the outside of the bearing is formed through the second seal member along the thrust direction. The first seal member is disposed in the bearing inner direction than the second seal member,
The rolling bearing according to claim 1, wherein the annular seal lip is inclined toward a fixed side direction of the first seal member.   The rolling ring according to claim 1, wherein the stationary wheel is configured as an inner ring disposed opposite to the inner side of the rotating ring, and the rotating wheel is configured as an outer ring disposed opposite to the outer side of the inner ring. bearing.   The rolling bearing according to claim 1, wherein lubrication is performed inside the bearing using oil or oil and compressed air. A rolling bearing used in a multi-stage rolling mill for rolling steel materials,
The rolling bearing according to claim 1, wherein the multi-stage rolling mill includes a rolling roller group for rolling the steel material, and the rolling bearing is assembled to a backing roll shaft of the rolling roller group. .

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