JP2002327752A - Bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing unit for a backup roll capable of extending the life of a whole unit by making the life of rollers uniform. SOLUTION: As the crowning amount δ1 of an end portion 22Da located in the outside of an axial direction in a roller 22D located in the outside in an axial direction is greater than the crowning amount δ2 of an end portion 22Ca located in the side of the same direction as the end portion 22Da in a roller 22C located in the inner side than the roller 22D in the axial direction, the surface pressure of the end portion of the roller 22D can be made to be close to that of the end portion of the roller 22C in the state where a shaft 21 is bent under a high load. Thus, life of the rollers in each row is uniformalized, and life of an entire bearing unit is be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a bearing device,
In particular, it relates to a bearing device for a backup roll.

[0002]

2. Description of the Related Art A backup roll used in a steel facility functions to support working rolls arranged on both sides of a steel sheet from behind and prevent deformation of the working roll during a straightening / rolling process of the steel sheet. . However, since an extremely excessive load is applied to the backup roll via the working roll during the straightening / rolling process, a bearing device that supports the backup roll on a fixed shaft is also used that can cope with a high load. I have.

As such a bearing device for supporting a backup roll, for example, as disclosed in Japanese Patent Application Laid-Open No. H11-325062, there is a bearing device in which the load capacity is increased by using rollers.

[0004]

By the way, in the bearing device for the backup roll of the prior art, there is a tendency that the life of the rollers in the outer row is shorter than the life of the rollers in the inner row. There is a problem that the bearing device needs to be repaired or replaced even though the service life is about to expire. The uneven life of the rollers is caused by the fact that the backup roll is subjected to an extremely large load during the straightening / rolling process of the steel sheet, so that the center of the fixed shaft whose both ends are supported by the housing bends. It is considered to be due to That is, since the inclination of the fixed shaft due to such deflection is close to zero at the center and increases toward the end, the roller diameter of each row is equal, and if the inner diameter of the outer ring and the outer diameter of the shaft are equal, The load received by the rollers increases in the rows closer to both ends, and is maximized at the outer contact ends.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a bearing device for a backup roll that can extend the life of the entire device by making the life of the rollers uniform. .

[0006]

In order to achieve the above object,
The bearing device of the present invention includes an outer ring, and a plurality of rollers arranged in two or more rows so as to freely roll between the outer ring and the shaft,
In the bearing device for a backup roll, the crowning amount of the axially outer end of the first row of rollers located outside in the axial direction is smaller than that of the second row of rollers located inward in the axial direction from the first row of rollers. The amount of crowning at the end of the roller in the same direction as the end is larger than that of the end.

[0007]

The bearing device of the present invention is a bearing device for a backup roll having an outer ring and a plurality of rollers arranged in two or more rows so as to roll freely between the outer ring and the shaft. The amount of crowning at the axially outer end of the first row of rollers at the outside is the same as the end of the second row of rollers at the inner side in the axial direction with respect to the first row of rollers. In the state where the shaft is deflected under a high load, the surface pressure of the end of the first row of rollers is increased by the amount of crowning of the first portion, and the surface pressure of the shaft is further increased than the crowning amount of the first row. It is possible to approach the surface pressure at the end of the second row of rollers, thereby making the life of each row of rollers uniform and extending the life of the entire bearing device. In this specification, the term “end” does not include a chamfer.

The crowning amount of the rollers in the first row is smaller than the crowning amount of the rollers in the second row.
Preferably it is 1.25 to 2 times.

The amount of crowning at the axially outer end of the first row of rollers located outside in the axial direction is greater than the amount of crowning at the axially inner end of the first row of rollers. The amount of crowning at the inner end is the second axially inward from the first row of rollers.
If the amount of crowning at the axially outer end of the row rollers is greater than the amount of crowning at the axially outer end thereof, the higher the amount of crowning at the axially inner end of the second row of rollers, the higher the load. When the shaft is bent in response to the pressure, the surface pressure received at the end of each roller can be equalized, which is preferable.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a four-row cylindrical roller bearing which is an example of a bearing device for a backup roll according to the first embodiment. In FIG. 1, a bearing device 10 includes an outer ring (here, a roll) 20,
Cylindrical rollers (hereinafter, referred to as four rows) are arranged between a shaft 21 (both of which may have an inner ring interposed therebetween) supported by a housing (not shown) and an outer ring 20 and the shaft 21 in order from the left in the figure. , Rollers) 22A to 22D.

The outer ring 20 is provided at the center of the inner circumference in the axial direction.
The roller 22 has a circumferentially continuous brim 20a.
B and 22C are arranged so as to sandwich the collar 20a. Note that an outer ring spacer may be used instead of the collar 20a. Outer ring spacers 23A and 23B are arranged between the rollers 22A and 22B and between the rollers 22C and 22D so as to fit on the inner periphery of the outer ring 20.
It is also possible to use an inner ring spacer instead of the outer ring spacer.

At both ends of the outer ring 20, an inner peripheral enlarged diameter portion 20b is provided.
20c are formed, and seals 25A, 2
Holders 24A and 24B that support the rollers 5B and hold down the rollers 22A and 22D are provided in a fitting manner. Furthermore,
Inner peripheral grooves 20d formed in the inner peripheral enlarged diameter portions 20b and 20c,
Ring-shaped retaining rings 26A and 26B for preventing the axial movement of the holders 24A and 24B are engaged with the holder 20e.

FIG. 2 is an enlarged view of the part II of the configuration of FIG. In FIG. 2, hatching of the cross section is omitted. 2, a roller 22D corresponds to a first row of rollers located on the outside in the axial direction, and the end portion 2 on the outside in the axial direction (right side in FIG. 2).
The crowning amount δ1 of 2Da is equal to the end 2 in the same direction as the end 22Da (the right side in FIG. 2) of the roller 22C corresponding to the second row of rollers axially inside the roller 22D.
It is larger than the crowning amount δ2 of 2Ca (δ1> δ2). On the other hand, the crowning amount of the opposite end 22Db of the roller 22D may be equal to the crowning amount of the same-direction end 22Cb of the roller 22C. It is also possible to do. The above relationship is the same in the rollers 22A and 22B.

FIG. 3 is the same as FIG. 2 showing a part of a bearing device 1 which is a comparative example in which the crowning amounts at both ends of the outer row rollers 2D and the inner row rollers 2C are set equal to δ2. It is a figure. Rollers 22C and 22 of the present embodiment
When comparing the stress distributions SDC and SDD received by D (FIG. 2) with the stress distributions SDC and SDD received by the rollers 2C and 2D of the comparative example, the stress distribution SDC received by the rollers 2C of the comparative example is as follows. The stress distribution SDC applied to the rollers 22C of the present embodiment is generally lower than SDC. However, the stress distribution SDC received by the roller 2D of the comparative example disposed on the axial end side is larger than the stress distribution SDD received by the roller 22D of the present embodiment, and in particular, the axial distribution (see FIG. (Right side in FIG. 3) at the end 2Da.

As described above, when the stress of only a part of the roller 2D is maximized, abrasion and surface damage are liable to occur at that part, and the roller 2D must be replaced in a relatively short cycle. It takes time and costs. On the other hand, according to the present embodiment, as shown in FIG. 2, by equalizing the stresses applied to the rollers 22C and 22D, the life of the outer rollers 22D is extended, and the bearing device 10 Reliability and durability can be improved.

FIG. 4 is a sectional view similar to FIG. 2 of a bearing device for a backup roll according to a second embodiment. The bearing device 110 shown in FIG. 4 differs from the above-described embodiment mainly in the shape of the rollers, and
The other components are denoted by the same reference numerals and description thereof is omitted.

In the present embodiment, the crowning amount δ1 of the axially outer end 122Da (right side in FIG. 4) of the first row of rollers located outside in the axial direction, that is, the roller 122D, is equal to the axial inner side (in the roller 122D). The crowning amount δ2 of the end 122Db at the left side in FIG. 4) is larger than the crowning amount δ2 of the second row of rollers located inside the roller 122D in the axial direction, that is, the axially outer portion (the right side in FIG. 4) of the roller 122C. It is larger than the crowning amount δ3 of the end 122Ca, and the crowning amount δ
3 is larger than the crowning amount δ4 of the end 122Cb on the inner side in the axial direction (left side in FIG. 4) of the roller 122C (δ1>δ2>δ3> δ4). By appropriately determining the crowning amounts δ1 to δ4 according to the deflection curve of the shaft 21 which bends under a load, the surface pressures received by the rollers 122C and 122D can be further equalized as shown in FIG. Thus, the life of the outer rollers 122D can be extended, and the reliability and durability of the bearing device 110 can be improved.

FIG. 5 is a view showing a roller 222 of the bearing device according to the third embodiment. FIG. 6 is a diagram showing the end shape of the roller 222 enlarged and projected two-dimensionally. As shown in FIG. 6, the end of the roller 222 has a first crowning part 222b connected to a contact part 222a that contacts the inner and outer rings (not shown), and a first crowning part 222b.
And a second crowning part 222c connected to the second crowning part 222c.
Through a flat end surface 222e.

In the shape projected two-dimensionally as shown in FIG. 6, when the curvature of the first crowning part 222b is R1, the curvature of the second crowning part 222c is R3, and the curvature of the chamfered part 222d is R2, R1> R3
> R2 holds, and 0.005 × R1 <
Since the relationship of R3> 0.1 × R1 holds, roller 2
It is possible to effectively suppress the surface pressure that is applied to the end portion (particularly, the second crowning portion 222c) of the second portion 22.

Although the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above embodiments, and that modifications and improvements can be made as appropriate. is there. For example, two or more rolling elements are sufficient.

[0021]

According to the present invention, there is provided a bearing device for a backup roll, comprising: an outer ring; and a plurality of rollers arranged in two or more rows so as to roll freely between the outer ring and a shaft. The amount of crowning at the axially outer end of the first row of rollers located axially outward is the same direction as the end of the second row of rollers located axially inward of the first row of rollers. In the state where the shaft is deflected under a high load, the surface pressure of the end of the roller in the first row is arranged axially inward of the end of the first row of rollers in a state where the shaft is bent under high load. The surface pressure at the end of the rollers in the second row can be approximated, whereby the life of the rollers in each row can be made uniform, and the life of the entire bearing device can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view of a four-row cylindrical roller bearing as an example of a backup roll bearing device according to a first embodiment.

FIG. 2 is an enlarged view of a part II of the configuration of FIG. 1 and also shows a surface pressure distribution of each part in an overlapping manner.

FIG. 3 is a view similar to FIG. 2 showing a part of a bearing device 1 as a comparative example.

FIG. 4 is a cross-sectional view similar to FIG. 2 of a bearing device for a backup roll according to a second embodiment.

FIG. 5 shows a roller 22 of a bearing device according to a third embodiment.
FIG.

FIG. 6 is a diagram showing an end shape of a roller 222 in an enlarged manner and projected two-dimensionally.

[Explanation of symbols]

 10, 110 Bearing device 20 Outer ring (roll) 21 Shaft 22A to 22D, 122C to 122D, 222 Roller

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J101 AA13 AA44 AA62 AA72 BA05 FA31 GA36 3J103 AA02 AA12 CA26 CA37 FA12 GA02 GA17

Claims (1)

[Claims] 1. A bearing device for a backup roll, comprising: an outer ring; and a plurality of rollers arranged in two or more rows so as to roll freely between the outer ring and a shaft. The amount of crowning at the outer end in the axial direction of the rollers in one row is greater than the amount of crowning at the end in the same direction as the end in the second row of rollers located inward in the axial direction from the rollers in the first row. Bearing equipment is also getting bigger.