JP2004169754A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for simplifying assembly work without causing sliding between a rotation shaft and an inner ring. <P>SOLUTION: The bearing device 1 of the invention comprises: the rotation shaft 3; a circular outer ring 5 disposed on an outer circumferential side of the rotation shaft 3; and a plurality of rollers 4 disposed rollingly between the rotation shaft 3 and the outer ring 5. The rotation shaft 3 is supported relatively rotatably with respect to the outer ring 5. An outer circumferential part 3a of the rotation shaft 3 being a contact face with the rollers 4 is cured. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bearing device, and more particularly, to a bearing device including a plurality of rolling elements between a rotating shaft and an outer ring, wherein the rotating shaft is supported rotatably with respect to the outer ring.
[0002]
[Prior art]
As a bearing device having a rolling element between a rotating shaft and an outer ring, there is a bearing device that supports a backup roll in a rolling mill of a steel material manufacturing facility, for example (see Patent Document 1, for example). FIG. 3 shows an example of such a conventional bearing device.
[0003]
As shown in FIG. 3, in the bearing device 50, the roll neck of the backup roll 51 is used as the rotation shaft 52. A two-row roller bearing 53 is provided on the outer periphery of the rotating shaft 52.
The roller bearing 53 has an inner ring 54 fixed to the outer periphery of the rotating shaft 52, and an outer ring 56 provided on the outer periphery of the inner ring 54 via a plurality of rollers 55 arranged in two rows. The plurality of rollers 55 are rolling elements of the roller bearing 53, and the rollers 55 roll between the inner raceway surface 54 a of the inner race 54 and the outer raceway surface 56 a of the outer race 56 so that the inner race 54 and the outer race 56 are relatively opposed to each other. Rotate. A bearing device 50 shown in FIG. 3 is configured such that an outer ring 56 is fixed to a housing (not shown) of a rolling mill, and a backup roll 51 rotates together with an inner ring 54.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 3-31442 (Page 2, Figure 1)
[0005]
[Problems to be solved by the invention]
By the way, as shown in FIG. 3, when assembling the roller bearing 53 on the outer periphery of the rotating shaft 52, after shrink-fitting and fixing the inner ring 54 to the rotating shaft 52, the inner ring raceway surface 54 a of the inner ring 54 is fixed. Co-grinding was required. This is because the center axis of the inner ring raceway surface 54a formed in a circumferential shape does not always coincide with the center axis of the rotation shaft 52, and the runout accuracy between the rotation shaft 52 and the inner ring raceway surface 54a deteriorates. This is because they can be lost. If the run-out accuracy between the rotating shaft 52 and the inner raceway surface 54a is poor, the forming accuracy at the time of sheet rolling will be reduced.
Therefore, in order to make the center axis of the inner raceway surface 54a coincide with the center axis of the rotating shaft 52 and improve the run-out accuracy, the so-called co-grinding for grinding the inner raceway surface 54a has been performed. As described above, the conventional bearing structure as described above requires a shrink-fitting step and a co-grinding step at the time of assembling, so that the assembling work is complicated.
[0006]
Further, since the rotating shaft 52 and the inner ring 54 are members having different configurations, the rotating torque may cause a slip between the rotating shaft 52 and the inner ring 54 during the operation of the backup roll 51. If slippage occurs, the rolling operation of the rolling mill may be inconvenient, and the roller bearing 53 and the backup roll 51 may be damaged.
[0007]
An object of the present invention is to provide a bearing device that simplifies an assembling operation and does not cause slippage between a rotating shaft and an inner ring.
[0008]
[Means for Solving the Problems]
A bearing device according to the present invention for achieving the above object is provided with a rotating shaft, an annular outer ring arranged on the outer peripheral side of the rotating shaft, and a rolling device disposed between the rotating shaft and the outer ring. A bearing device comprising a plurality of rolling elements, wherein the rotating shaft is supported so as to rotate relative to the outer ring, wherein the rotating shaft has a contact surface with the rolling elements that is hardened. I have.
[0009]
According to the bearing device having such a configuration, the contact surface of the rotating shaft with the rolling element has strength as a raceway surface of the rolling element. Therefore, the function as an inner ring of the roller bearing can be given to the outer periphery of the rotating shaft, and there is no need to provide another inner ring as the outer periphery of the rotating shaft. Therefore, the shrink-fitting step and the co-grinding step, which were conventionally required when assembling the inner ring, are not required, and the assembling work of the bearing device can be simplified.
Further, since there is no need to provide an inner ring, slippage between the rotating shaft and the inner ring can be fundamentally eliminated.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a bearing device according to the present invention will be described with reference to FIGS.
(1st Embodiment)
FIG. 1 is a schematic view of a main part showing a first embodiment of a bearing device according to the present invention.
[0011]
The bearing device 1 of the present embodiment shown in FIG. 1 is used, for example, to support a backup roll of a rolling mill. That is, the rotating shaft 3 is a roll neck portion of the backup roll 2. Some rolling mills generate a rolling load of 1000 tons or more during operation, and in order to rotatably support the backup roll 2, the bearing device 1 is required to have a high durable strength.
[0012]
As shown in FIG. 1, in the bearing device 1, an outer ring 5 formed in an annular shape with a gap provided on the outer peripheral side of the rotating shaft 3 is disposed, and between the rotating shaft 3 and the outer ring 5. The rollers 4 as a plurality of rolling elements are arranged in two rows in the circumferential direction of the rotating shaft 3. The rollers 4 are cylindrical, that is, the bearing device 1 has a double-row cylindrical roller bearing configuration.
The rollers 4 roll while contacting the outer peripheral portion 3a of the rotating shaft 3 and the outer raceway surface 5a of the outer race 5, so that the rotating shaft 3 and the outer race 5 can rotate relative to each other. In the present embodiment, the outer ring 5 is fixed to a housing (not shown) of a rolling mill, and the backup roll 2 is configured to rotate. In addition, the outer race 5 is formed with a flange 6 for restricting the axial movement of the roller 4.
[0013]
Further, the bearing device 1 is designed to have a high load capacity so that a rolling load during rolling can be applied. Usually, the outer ring, the inner ring, and the rolling elements of the roller bearing used to support the backup roll are designed to have a high load capacity. However, the bearing device 1 of the present embodiment has the rotating shaft 3 in addition to the outer ring 5 and 4. Has been subjected to a curing treatment. Conventionally, the rotating shaft has not been subjected to the hardening treatment. However, the rotating shaft 3 of the present embodiment is provided with a hardening treatment on at least the surface on which the rollers 4 come into contact with the rolling surface and the inside thereof to perform the hardening treatment. It is made so that the strength that can function as an inner ring is obtained.
Thus, the bearing device 1 does not need to provide an inner ring as a bearing device that supports the backup roll, and can apply a rolling load by directly rolling the roller 4 on the outer peripheral portion 3a of the rotating shaft 3. I have.
[0014]
Hardening treatments that can be used in the present embodiment include, for example, induction hardening, carburizing and quenching, chilling, and overlay welding.
[0015]
Induction hardening can be mainly used for carbon steel, and can improve abrasion resistance and fatigue resistance. Curing properties obtained by electrical control can be controlled. In addition, quenching can be performed only on a portion that requires curing. Furthermore, the torsional strength and the torsional fatigue strength can be increased as compared with other heat treatments, and the strength required for the rotating shaft 3 can be effectively obtained as in the present embodiment.
[0016]
Carburizing and quenching is a method of processing a low-carbon steel having good workability and then increasing the amount of carbon on the surface to quench and harden. In this curing treatment, only the surface layer is cured, so that the internal toughness can be maintained and the abrasion resistance of the surface can be increased.
[0017]
In the chilling process, when casting cast iron in the casting process, the cast iron is quenched (chilled) by placing a mold on the surface to be hardened, and the surface on which the mold is placed is turned into white pig iron. The part and the inside that are not exposed are gray iron. Thereby, the wear resistance of the surface and the toughness inside can be obtained.
[0018]
In overlay welding, for example, a metal powder containing a carbide is melted to form a hardened layer at a desired location, thereby performing a hardening treatment on the surface. Thereby, the abrasion resistance of the surface can be improved. The thickness of the hardened layer may be a thin film or may be formed so as to positively increase the thickness.
[0019]
As described above, in the bearing device 1 of the present embodiment, the rotating shaft 3 is given a function equivalent to that of the conventional inner ring by hardening the rotating shaft 3. Therefore, there is no need to provide an inner ring, and there is no need to perform a shrink-fitting step or a co-grinding step for assembling the inner ring. Therefore, the workability of assembling the bearing device 1 can be greatly improved. In addition, the problem that the inner ring slides with respect to the rotating shaft 3 does not occur.
Furthermore, since the distance between the rotating shaft 3 and the outer ring 5 is increased by the thickness of the inner ring by not providing the inner ring, the load capacity of the bearing device 1 can be increased by increasing the diameter of the roller 4. Can be. When the size of the roller 4 is not changed, the outer diameter of the outer ring 5 can be reduced, and the bearing device 1 can be reduced in size to save space.
[0020]
(2nd Embodiment)
Next, a second embodiment of the bearing device according to the present invention will be described.
FIG. 2 is a schematic diagram of a main part showing a second embodiment of the bearing device according to the present invention.
As shown in FIG. 2, the bearing device 10 includes a rotating shaft 12 of a backup roll 11, an annular outer ring 14 disposed on the outer peripheral side of the rotating shaft 12, and rolling between the rotating shaft 12 and the outer ring 14. And a plurality of rollers 13 that are freely disposed. The outer races 14 and 13 have the same configuration as the outer races 5 and the rollers 4 of the first embodiment described above.
[0021]
The outer peripheral portion 12a of the rotating shaft 12 that comes into contact with the rollers 13 is hardened. The outer peripheral portion 12a is preferably formed so as to have an outer diameter equivalent to that when the conventional inner ring is fixed to the rotating shaft 3 of the first embodiment described above.
As the hardening treatment that can be used in the present embodiment, for example, the above-mentioned overlay welding, bonding with a metal or ceramic capable of obtaining a function corresponding to the inner ring, and the like are given.
[0022]
In the case where the outer peripheral portion 12a is formed by joining metals and ceramics, it is preferable that carbon steel or ceramics having a desired shape and made of a material suitable for use as the inner ring be welded and joined. Alternatively, a ceramic coating may be applied to the surface to which the desired carbon steel or the like is bonded.
[0023]
As in the first embodiment, the bearing device 10 of the present embodiment does not need to be provided with an inner ring, so that the assembling workability can be greatly improved. In addition, the problem that the inner ring slides with respect to the rotating shaft 12 does not occur.
Further, since the outer peripheral portion 12a of the rotating shaft 12 has the same outer diameter as that of the case where the conventional inner ring is provided, the outer ring or the roller (see FIG. 3) of the conventionally used roller bearing can be used as it is. it can.
[0024]
In the bearing device of the above-described embodiment, the rollers are arranged in two rows, but the bearing device of the present invention is not limited to this arrangement. For example, in order to obtain an arrangement of four rows, two sets of rollers and one outer ring may be provided side by side, or one set of four rows of rollers and one outer ring may be provided. You may do it.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a bearing device that simplifies an assembling operation and does not cause slippage between a rotating shaft and an inner ring.
[Brief description of the drawings]
FIG. 1 is a schematic view of a main part showing a first embodiment of a bearing device according to the present invention.
FIG. 2 is a schematic diagram of a main part showing a second embodiment of the bearing device according to the present invention.
FIG. 3 is a schematic diagram of a main part showing an example of a conventional bearing device.
[Explanation of symbols]
1 Bearing device (first embodiment)
2 Backup roll 3 Rotary shaft 3a Outer peripheral part 4 Roller (rolling element)
5 Outer ring 5a Outer ring raceway surface 6 Collar portion 10 Bearing device (second embodiment)
12 Rotary shaft 12a Outer periphery

Claims (1)

A rotating shaft, an annular outer ring arranged on the outer peripheral side of the rotating shaft, and a plurality of rolling elements rotatably arranged between the rotating shaft and the outer ring, wherein the rotating shaft is A bearing device rotatably supported on the outer ring,
The bearing device, wherein a contact surface of the rotating shaft with the rolling element is hardened.

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