JP2004076833A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost bearing device with a sealing body satisfying both of sealing performance and less heat/wear. <P>SOLUTION: When relative rotation occurs between an inner ring 12 and an outer ring 13, side walls 27f, 27g approach each other according to the deformation of a thin portion 27e based on centrifugal force within a preset rotating speed. When the preset rotating speed S is attained, the side walls 27f. 27g abut on each other in such a manner that the rate of the deformation of the sealing portion 27b to the rotating speed is different between pre-abutment and post-abutment. As a result, even when relative strong centrifugal force operates in a high rotating speed region, the sealing portion 27b is less deformed to effectively develop labyrinth function, e.g., and suppress interference with peripheral parts. Furthermore, no need exists for other parts including a stopper to prevent the deformation of the sealing portion, resulting in the low-cost bearing device. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bearing device including a roll neck bearing used for a rolling mill of steel equipment, for example.
[0002]
[Prior art]
As a roll neck bearing used for a work roll or an intermediate roll of a hot rolling mill or a cold rolling mill, a double-row or four-row tapered roller bearing capable of supporting a large load is generally used. .
[0003]
By the way, in rolling mills and the like, high-pressure water is supplied to work rolls and plates in order to accurately maintain the thickness of products and to remove scale generated during rolling. The cooling water is also used to cool the chocks and bearings. Accordingly, the roll neck bearing inherently requires a sealing device for preventing such intrusion of cooling water or the like.
[0004]
As such a sealing device, there is one provided with a contact-type seal such as an oil seal as described in Japanese Utility Model Application Laid-Open No. 6-82437. In such an oil seal according to the related art, a core metal is fitted to the inner peripheral surface on the outer ring side, and a seal portion extending from the core metal is brought into contact with the outer peripheral surface on the inner ring side. According to this conventional technique, a simple and inexpensive sealing device is provided.
[0005]
By the way, in recent years, the speed of a rolling mill or the like has been increased in order to promote the efficiency of work, whereby the operating environment of the bearing has become severe, and the sealing performance under high-speed conditions has been secured. There is a need. However, the upper limit of the allowable rotation speed at which a contact-type seal such as a normal oil seal can be used is the heat generation and abrasion of the sliding portion, the performance of the selected sealing material (usually, the lower the cost, the higher the rotation speed). In general, it is considered difficult to use a contact-type seal at a peripheral speed of several m / s to 10 m / s or more.
[0006]
As one of measures against such a high-speed use, a seal utilizing deformation of the seal due to centrifugal force accompanying rotation can be considered. Such a seal enhances the sealing effect by bringing the lip into contact with the sliding member below the upper limit of the permissible rotational speed of the contact-type seal. By causing the lip to be in a non-contact state with the sliding member by the deformation and exhibiting a so-called labyrinth seal function, it is possible to alleviate or eliminate the problem of heat generation and increase in wear while ensuring sealing performance.
[0007]
[Problems to be solved by the invention]
By the way, one problem in the seal using the deformation of the seal based on the centrifugal force is that in a high rotation speed region, the lip is excessively deformed by a large centrifugal force (for a lip having a constant thickness, it is almost equal to the square of the rotation speed. The amount of deformation increases in proportion), the function of a labyrinth seal may be insufficient, and interference with surrounding components may occur. However, if the rigidity of the lip is increased in order to suppress deformation in such a high rotational speed range, the lip will not be in a non-contact state with the sliding member even if the upper limit of the allowable rotational speed described above is exceeded. Heat and abrasion may increase. To solve such a problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 7-332377, it is conceivable to separately provide a stopper for suppressing the deformation of the lip in a high rotation speed range, but this increases the number of parts. However, there is a problem that it takes time to perform adjustment at the time of assembly.
[0008]
Accordingly, an object of the present invention is to provide a bearing device provided with a seal body that achieves both sealing performance and suppression of heat generation and abrasion at a low cost, in view of the problems of the related art.
[0009]
[Problems to be solved by the invention]
The bearing device of the present invention,
Inner ring,
Outer ring,
A double-row rolling element rotatably arranged between the inner ring and the outer ring;
A seal member attached to a rotating wheel of the inner ring and the outer ring, the seal member including a seal portion made of an elastic body;
A seal sliding member attached to the fixed ring of the inner ring and the outer ring and abutting on the seal portion,
When a relative rotation occurs between the inner ring and the outer ring, the seal portion is elastically deformed by receiving a centrifugal force corresponding to the rotation speed, and is rotated at a rotation speed lower than a predetermined rotation speed. Although it is separated in speed, it has a contact portion that comes in contact at a rotation speed higher than the predetermined rotation speed, and after the contact portion comes into contact, it is compared with before the contact of the contact portion. Thus, the rigidity of the seal portion with respect to the elastic deformation is increased.
[0010]
[Action]
According to the bearing device of the present invention, the inner race, the outer race, a double-row rolling element rotatably disposed between the inner race and the outer race, and the rotating race of the inner race and the outer race. A sealing member provided with a sealing portion made of an elastic body, and a seal sliding member attached to a fixed ring of the inner ring and the outer ring and abutting on the sealing portion; When a relative rotation occurs between the inner ring and the outer ring, the inner ring is elastically deformed by receiving a centrifugal force corresponding to the rotation speed, and is separated at a rotation speed lower than a predetermined rotation speed. However, at a rotation speed equal to or higher than the predetermined rotation speed, it has an abutting portion that abuts, and after the abutting portion abuts, compared to before the abutting of the abutting portion, Since the rigidity of the seal part with respect to elastic deformation is increased, When a strong centrifugal force proportional to the square of the rotation speed is received in a high rotation speed region where the contact portion abuts, by increasing the rigidity related to the elastic deformation of the seal portion to resist it, Elastic deformation can be suppressed to a small value, whereby, for example, a labyrinth sealing function can be effectively exerted, and interference with surrounding components can be suppressed. Further, there is no need to provide another component such as a stopper in order to prevent the elastic deformation of the seal portion, and a low-cost bearing device is provided.
[0011]
Preferably, the contact portion is at least one of side walls of a circumferential groove (slit) formed on an outer peripheral surface of the seal portion.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing the periphery of a work roll end of a rolling mill supported using the bearing device according to the present invention. In FIG. 1, a four-row tapered roller bearing 10 is capable of being divided into two rows of inner rings (rotating wheels) 12 that support a work roll 1 of a rolling mill and that can be divided in an axial direction, and is capable of being divided in an axial direction attached to a housing 2. A plurality of rows of outer rings (fixed wheels) 13, a plurality of rows of tapered rollers (rolling elements) 14 each disposed between the inner ring 12 and the outer ring 13, and a retainer 15 for holding the tapered rollers 14. Consists of Sealing devices 20 are arranged on both sides of the bearing 10. The bearing 10 and the sealing device 20 constitute a bearing device. Since the pair of sealing devices 20 have the same configuration, only the right sealing device 20 will be described.
[0013]
FIG. 2 is an enlarged view of a portion indicated by an arrow II in FIG. FIG. 3 is an enlarged view of the periphery of the seal portion in FIG. 2, and hatching of the seal portion is omitted. The sealing device 20 includes a ring-shaped outer ring holder 21, a seal sliding member 22 attached to the outer ring holder 21, a base 24 fitted around the end 12 a of the inner ring 12, and a screw 25 on the base 24. A seal holding member 26 is attached via the seal holding member 26 and a seal body 27 held by the seal holding member 26.
[0014]
A step portion 21a is formed on the left end surface of the outer ring holder 21 in FIG. 2, while a step portion 13a is formed on the right end surface of the outer ring 13 in FIG. 2 so as to face the step portion 21a, When the outer race holder 21 is assembled to the outer race 13, the steps 21a and 13a are engaged with each other.
[0015]
Further, the outer ring holder 21 has a peripheral groove 21b on the outer periphery, and an O-ring 28 is disposed in the peripheral groove 21b. The space is sealed. Further, a step 21c is formed near the inner periphery of the left end face of the outer ring holder 21 in FIG. 2, and the step 21c has a circumferential cross-section so as to be sandwiched between the outer ring 13 and the outer ring holder 21. A substantially L-shaped seal sliding member 22 is attached.
[0016]
The base 24 has a flange portion 24a extending radially outward from the outer periphery at the left end in FIG. 2, and the seal holding member 26 has a flange portion 26a extending radially outward from the outer periphery at the right end in FIG. are doing. By screwing a screw 25 inserted through the through hole 26b of the seal holding member 26 into a screw hole 24b formed in the base 24, the core metal 27a of the seal body 27 is formed between the flange portions 24a, 26a. Is to be clamped.
[0017]
The annular seal body 27 includes a core metal 27a having a substantially L-shaped cross section in the circumferential direction, and a seal portion 27b that is bonded to a radially outer edge of the metal core 27a and extends from the core metal 27a toward the seal sliding member 22. Consists of The seal portion 27b is formed of an elastic body such as fluoro rubber, nitrile rubber, acrylic rubber, and the like.
[0018]
As shown in FIG. 3, the seal portion 27b has a substantially tubular shape, and has a lip 27c protruding inward in the radial direction from the left end in FIG. ) 27d. The side walls 27f and 27g of the circumferential groove 27d constitute a contact portion. When the bearing device is at rest, the lip 27c is in contact with the outer peripheral surface of the seal sliding member 22, as indicated by the solid line in FIG. 3, according to the initial contact force.
[0019]
Next, the operation of the present embodiment will be described. In FIG. 1, when the work roll 1 of the rolling mill rotates together with the inner ring 12, the tapered rollers 14 roll between the inner ring 12 and the outer ring 13, whereby the bearing 10 rotates the work roll 1 with respect to the housing 2. It can be freely supported.
[0020]
In such a case, since a large amount of cooling water is applied around the work roll 1, there is a possibility that the cooling water or the like may scatter to the outside (right side) of the sealing device 20 in FIG. Here, in the present embodiment, first, when the work roll 1 is stationary, the lip 27c is in contact with the outer peripheral surface of the seal sliding member 22 with the initial contact force. Intrusion can be prevented.
[0021]
Furthermore, as the work roll 1 starts rotating and the inner ring 12 rotates with it, the seal body 27 attached to the inner ring 12 also rotates. However, since the seal portion 27b is mounted in a cantilever manner, Due to the centrifugal force, the end on the side of the lip 27c is deformed so as to be turned outward, as shown by the dotted line in FIG. According to the present embodiment, in the rotation speed range lower than the predetermined rotation speed S, the thin portion 27e having low rigidity inside the circumferential groove 27d greatly contributes to the elastic deformation. The proportion of the amount is large. That is, as the rotation speed increases, the seal portion 27b is easily elastically deformed, and the elastic deformation acts to reduce the initial contact force of the lip 27c against the seal sliding member 22, and the substantial contact force , So that heat generation and wear can be suppressed.
[0022]
On the other hand, when the work roll 1 rotates at a higher speed and reaches a predetermined rotation speed S, the side walls 27f and 27g of the circumferential groove 27d come into contact with each other due to elastic deformation. As shown by the dotted line, the thin portion 27e inside the circumferential groove 27d hardly deforms, and therefore, the ratio of the amount of deformation to the rotation speed decreases. Therefore, even when a large centrifugal force is received in a high rotation speed range, an increase in the gap Δ between the lip 27c of the seal portion 27b and the outer peripheral surface of the seal sliding member 22 can be suppressed, and the labyrinth seal function can be used for shaking off With the effect, intrusion of cooling water can be suppressed. In such a case, since the lip 27c and the seal sliding member 22 are separated from each other, heat generation and wear do not occur.
[0023]
FIG. 4 is a graph showing the relationship between the rotation speed and the amount of deformation. The deformation of the seal portion 27b of the seal body 27 according to the present embodiment is indicated by a solid line A. Note that a dotted line B shows a modification of the comparative example in which the peripheral groove 27d is not provided (other shapes are equal). As is apparent from FIG. 4, in the comparative example indicated by the dotted line B, since the amount of deformation in the low rotation speed range is small, the problem of heat generation and abrasion is likely to occur, and the amount of deformation is excessive in the high rotation speed region, and the labyrinth Although the function of the seal cannot be sufficiently exerted, according to the present embodiment, the side walls 27f and 27g of the circumferential groove 27d are brought into contact with each other in a rotation speed range higher than the predetermined rotation speed S. The problem in the example is avoided. Further, according to the present embodiment, in order to achieve such two-stage deformation, there is no need to provide a separate component, and a low-cost and simple configuration can be achieved.
[0024]
FIG. 5 is a sectional view similar to FIG. 3 showing a seal body according to the second embodiment, but omits a seal sliding member. In FIG. 5, the seal body 127 includes a core metal 27a having the same configuration as that of the above-described embodiment, and a seal portion 127b having a different configuration. The seal portion 127b differs from the above-described embodiment in the shape of the circumferential groove 127d. That is, both side walls 127f and 127g constituting the abutting portion of the circumferential groove 127d are inclined, so that the cross section of the circumferential groove 127d is V-shaped. In addition, it is preferable to form a round groove 127h for stress relaxation at the bottom of the circumferential groove 127d. Also in the present embodiment, as in the above-described embodiment, the configuration is such that the side walls 127f and 127g of the circumferential groove 127d are brought into contact with each other in a rotation speed range higher than the predetermined rotation speed S, so that the circumferential groove 127d is formed. The elastic deformation of the deformed portion 127e inside is suppressed, and the same operation and effect are obtained.
[0025]
As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the present invention. . For example, the seal portion shown in FIGS. 3 and 5 has a constant thickness except for the peripheral groove, but may have a tapered shape or a multi-stage thickness.
[0026]
【The invention's effect】
According to the bearing device of the present invention, the inner race, the outer race, a double-row rolling element rotatably disposed between the inner race and the outer race, and the rotating race of the inner race and the outer race. A sealing member provided with a sealing portion made of an elastic body, and a seal sliding member attached to a fixed ring of the inner ring and the outer ring and abutting on the sealing portion; When a relative rotation occurs between the inner ring and the outer ring, the inner ring is elastically deformed by receiving a centrifugal force corresponding to the rotation speed, and is separated at a rotation speed lower than a predetermined rotation speed. However, at a rotation speed equal to or higher than the predetermined rotation speed, it has an abutting portion that abuts, and after the abutting portion abuts, compared to before the abutting of the abutting portion, Since the rigidity of the seal part with respect to elastic deformation is increased, When a strong centrifugal force proportional to the square of the rotation speed is received in a high rotation speed region where the contact portion abuts, by increasing the rigidity related to the elastic deformation of the seal portion to resist it, Elastic deformation can be suppressed to a small value, whereby, for example, a labyrinth sealing function can be effectively exerted, and interference with surrounding components can be suppressed. Further, there is no need to provide another component such as a stopper in order to prevent the elastic deformation of the seal portion, and a low-cost bearing device is provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the periphery of a work roll end of a rolling mill supported by using a bearing device according to the present invention.
FIG. 2 is an enlarged view of a portion indicated by an arrow II in FIG.
FIG. 3 is an enlarged view showing a periphery of a seal portion of FIG. 2;
FIG. 4 is a graph showing a relationship between a rotation speed and a deformation amount.
FIG. 5 is a sectional view similar to FIG. 3 showing a seal body according to a second embodiment, but omits a seal sliding member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Work roll 2 Housing 12 Inner ring 13 Outer ring 14 Tapered roller 20 Sealing device 27,127 Seal body 27b, 127b Seal part

Claims (2)

Inner ring,
Outer ring,
A double-row rolling element rotatably arranged between the inner ring and the outer ring;
A seal member attached to a rotating wheel of the inner ring and the outer ring, the seal member including a seal portion made of an elastic body;
A seal sliding member attached to the fixed ring of the inner ring and the outer ring and abutting on the seal portion,
When a relative rotation occurs between the inner ring and the outer ring, the seal portion is elastically deformed by receiving a centrifugal force corresponding to the rotation speed, and is rotated at a rotation speed lower than a predetermined rotation speed. Although it is separated in speed, it has a contact portion that comes in contact at a rotation speed higher than the predetermined rotation speed, and after the contact portion comes into contact, it is compared with before the contact of the contact portion. And a stiffness with respect to elastic deformation of the seal portion. The bearing device according to claim 1, wherein the contact portion is at least one of a side wall of a circumferential groove formed on an outer peripheral surface of the seal portion.

Images