JP2574487Y2 - Bearing device for hot-dip plating tank - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip galvanizing tank bearing device in which a shaft is supported by a metal housing via a ceramic ball bearing in a hot-dip galvanizing tank.

[0002]

2. Description of the Related Art For example, a shaft such as a pot roll (sink roll) or a support roll is disposed in a hot-dip galvanizing tank for a steel sheet, and these are supported by a support member via a bearing. The bearing has a high temperature of 450 to 550 ° C,
Since it is used under high load conditions, it is required to have a function of absorbing thermal expansion in the axial direction of the shaft and inclination of the center line due to thermal deformation of the shaft such as bending.

Conventionally, as a bearing device used in a hot-dip metal plating tank, a ceramic inner ring having a raceway,
A plurality of ceramic balls arranged in the raceway of the inner ring, and ceramics having a cylindrical or concave spherical raceway surface capable of moving relative to the balls in the axial direction and having a clearance fit in the housing. A bearing provided with a ceramic full ball bearing comprising an outer ring is used (see Japanese Utility Model Application Laid-Open No. 63-89428).

[0004]

However, in the ball bearing provided in the conventional bearing device, since the raceway surface of the outer ring and the ball come into contact at one point, when a large load is applied, the raceway surface of the outer ring and the ball are in contact with each other. There is a problem in that a large contact stress is generated in between, and the life is shortened due to wear due to short-term use.

An object of the present invention is to provide a bearing device for a hot-dip plating tank which solves the above-mentioned problems.

[0006]

A first bearing device for a hot-dip plating bath according to the present invention is a hot-dip plating bath for rotatably supporting a shaft with respect to a housing via a ceramic ball bearing in a hot-dip plating bath. A tank bearing device,
In the housing, a metal holder having an outer peripheral surface formed into a convex spherical surface that is in sliding contact with the inner peripheral surface of the housing and having an annular groove formed on the inner peripheral surface is disposed, and a ceramic ball bearing is fitted and stopped on the shaft. An inner ring, a mating outer ring divided into two by a plane perpendicular to the central axis and fitted in the annular groove of the holder, and a plurality of balls arranged between the inner and outer wheels, at least one end face of the outer ring A spacer made of a metal having a higher thermal expansion coefficient than the metal forming the holder is interposed between the spacer and the side surface of the annular groove.

The second bearing device for a hot-dip plating bath according to the present invention is a bearing device for a hot-dip plating bath which rotatably supports a shaft via a ceramic ball bearing in a hot-dip plating bath. And in the housing,
An outer peripheral surface is formed as a convex spherical surface that is in sliding contact with the inner peripheral surface of the housing, and a corrosion-resistant material holder having an annular groove formed on the inner peripheral surface is disposed. The ceramic ball bearing is mounted on a plane perpendicular to the central axis. An inner ring which is divided and fitted to the shaft and fixed to the shaft by a stopper member, an outer ring fitted in the annular groove of the holder, and a plurality of balls arranged between the inner and outer wheels; A spacer made of a metal having a larger thermal expansion coefficient than the metal forming the shaft is interposed between at least one of the end surfaces and the side surface of the stop member.

[0008]

According to the above two bearing devices, the ball bearing is provided with the mating outer ring or inner ring divided into two by a plane perpendicular to the central axis, so that the ball bearing can be of a three-point contact type or a four-point contact type. can do. Therefore, the generated contact stress is smaller than that of the related art, and the load capacity is increased.

According to the above two bearing devices, a holder having a convex spherical surface whose outer peripheral surface is in sliding contact with the inner peripheral surface of the housing and having an annular groove formed in the inner peripheral surface is arranged in the housing. Since the outer ring of the ball bearing is fitted in the annular groove of the holder, if the shaft extends in the thrust direction due to thermal expansion, the holder slides with respect to the housing and the bearing moves together with the holder. Elongation is absorbed. When the center line is inclined due to thermal deformation such as bending of the shaft, the inclination of the center line of the shaft is absorbed by tilting the holder with respect to the housing and the bearing together with the holder.

According to the first bearing device, a spacer made of a metal having a larger thermal expansion coefficient than the metal forming the holder is interposed between at least one of the end surfaces of the outer race and the side surface of the annular groove. Therefore, a gap is prevented from being formed between the holder and the outer ring during use. That is, since the holder is made of metal and the outer ring is made of ceramic, the coefficient of thermal expansion of the holder is larger than that of the holder, and if the spacer is not interposed, the holder and the outer ring can be used at a high temperature in a plating bath. There is a gap between them, and the internal specifications of the ball bearing change. In addition, when a gap is formed, a plating solution intrudes into the gap, and remains when the housing and the shaft are lifted out of the plating bath, solidifies, and the holder and the outer ring are thermally contracted. The outer ring may be cracked.

According to the second bearing device, between at least one end face of the inner race and the side face of the stopper member,
Since the spacer made of a metal having a larger thermal expansion coefficient than that of the metal forming the shaft is interposed, it is possible to prevent a gap from being formed between the stopper member and the inner ring during use. That is, since the shaft is made of metal and the inner ring is made of ceramics, the coefficient of thermal expansion of the shaft is larger than that of the shaft, and if the spacer is not interposed, the stop member and the inner ring are used when used at a high temperature in a plating bath. A gap is generated between them, and the internal specifications of the ball bearing change. In addition, when a gap is formed, a plating solution infiltrates into the gap, remains when the housing and the shaft are lifted out of the plating bath, solidifies, and heat-shrinks the shaft and the inner ring. The inner ring may be cracked.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the bearing device according to the present invention.

In FIG. 1, a hot-dip galvanizing tank bearing device is configured such that a metal shaft (1) is placed in a hot-dip galvanizing tank via a ball bearing (2) without a retainer and a metal housing (3). I support it.

The total ball bearing (2) includes an inner ring (4) fitted and fixed on the shaft (1), a combined outer ring (5) divided into two parts by a plane perpendicular to the central axis, and both inner and outer rings (4) ( 5) Multiple balls placed between
(6) The three-point contact type or the four-point contact type. The inner ring (4), the outer ring (5) and the ball (6) are each formed of ceramics such as Si ₃ N ₄ . The inner ring (4) is fitted to the shaft (1) by a clearance fit,
It is clamped between a step (1a) of the shaft (1) and a metal sleeve (7) fitted to the shaft (1). Sleeve (7) is formed the same material as the shaft (1), for example, stainless steel such as SUS 403. Outer ring (5) is housing (3)
Made of metal, for example, SUS403
(8). The holder (8) has a convex spherical surface (8a) whose outer peripheral surface is in sliding contact with the inner peripheral surface of the housing (3), and has an annular groove (8b) formed on the inner peripheral surface.
The outer ring (5) is fitted inside b). A spacer (9) made of a metal having a larger thermal expansion coefficient than that of the metal forming the holder (8), for example, an aluminum alloy, is provided between both axial end surfaces of the outer ring (5) and both side surfaces of the annular groove (8b). Is interposed.

The thermal expansion coefficient of Si ₃ N ₄ forming the bearing (2) is 3.2 × 10 ⁻⁶ , and the thermal expansion coefficient of SUS403 forming the holder (8) is 11.7 × 10 ^{−. The} coefficient of thermal expansion of the aluminum alloy forming the spacer (9) is 23.7 × 10 ⁻⁶ .

When the shaft (1) extends in the thrust direction, the convex spherical surface (8a) of the holder (8) slides on the inner peripheral surface of the housing (3), and the bearing (2) moves on the holder (8). ) With housing
By moving with respect to (3), the elongation of the shaft (1) is absorbed. Also, when the shaft (1) undergoes thermal deformation such as bending and the center line is inclined, the convex spherical surface (8a) of the holder (8) slides on the inner peripheral surface of the housing (3). The holder (8) tilts with respect to the housing (3), and the bearing (2) tilts together with the holder (8), thereby absorbing the tilt of the center line of the shaft (1).

When the bearing (2) and the holder (8) thermally expand during use at a high temperature in the hot-dip plating bath, the thermal expansion coefficient of the spacer (9) is larger than that of the holder (8). , The both ends of the outer ring (5) and the annular grooves (8
The formation of a gap between both side surfaces of b) is prevented. When such a gap occurs, the following problem occurs. That is, the internal specifications of the bearing (2) change, and desired bearing performance cannot be obtained. For example, the above gap causes a gap between the divided surfaces of the mating outer ring (5), and the ball (6) and the outer ring
The contact point with (5) changes, and in the worst case, the ball (6) rolls on the edge of the split surface, and the brittle material S
There is a possibility that the bearing (2) may be broken due to chipping of i ₃ N ₄ . Also, the plating solution enters the gap and the housing
(3) When the shaft (1) is pulled out of the plating bath, it remains there and solidifies, and the outer ring (5) may be cracked due to the heat shrinkage of the holder (8) and the outer ring (5). is there.

FIG. 2 shows a second embodiment of the bearing device according to the present invention. The same components as those shown in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, a full ball bearing (11) for supporting the shaft (1) with respect to the housing (3) includes a mating inner ring (12) divided into two parts by a plane perpendicular to the center axis, and a normal outer ring. (13). Both the inner and outer wheels (12) and (13)
It is formed of ceramics such as ₃ N _4. Inner ring (12)
A spacer (14) made of a metal having a larger coefficient of thermal expansion than the metal forming the shaft (1), for example, an aluminum alloy is interposed between the end surface of the shaft and the end surface of the metal sleeve (stop member) (7). ing. By this spacer (14), the shaft
Even if (1) expands or contracts, the inner ring (12)
Can be pressed against the step (1a).
A gap can be prevented from being generated between the divided surfaces in 2).

The end face of the outer ring (13) and a SUS403 holder
No spacer is interposed between the side face of the annular groove (8b) of (8). However, as in the first embodiment, a spacer (9) may be interposed in this portion. In this embodiment, the holder (8) may be made of the same material as the outer race (13). In this case, outer ring (13)
A gap can be prevented from being generated between the groove and the side surface of the annular groove (8b). Therefore, a mating outer ring can be used instead of the outer ring (13).

[0022]

According to the bearing device for a hot-dip plating bath of the present invention, as described above, the generated contact stress is smaller than that of a conventional ball bearing, so that the inner and outer wheels and the balls are worn. Is less likely to occur and the life is improved,
Load capacity increases. Further, the elongation of the shaft in the thrust direction and the inclination of the center line of the shaft are absorbed. Further, it is possible to prevent a change in the internal specifications of the ball bearing at the time of use at a high temperature, and it is possible to prevent a race of a bearing ring cooled after use at a high temperature.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a bearing device according to the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the bearing device according to the present invention.

[Explanation of symbols]

 1 shaft 2 full ball bearing 3 housing 5 mating outer ring 8 holder 8a convex spherical surface 8b annular groove 9 spacer

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seiichi Iida 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Ryuto Enomoto 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan (56) References JP-A 3-59359 (JP, U) JP-A 2-1155 (JP, U) JP-A 1-94450 (JP, U) JP-A 63-89428 (JP) , U) Actually open 60-82457 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23C 2/00-2/40 F16C 19/06 F16C 35/077 F16C 13/02

Claims (2)

(57) [Scope of request for utility model registration] 1. A hot-dip galvanizing tank bearing device for supporting a shaft rotatably with respect to a housing via a ceramic ball bearing in a hot-dip galvanizing tank, wherein the outer peripheral surface is inside the housing. A metal holder having a convex spherical surface that is in sliding contact with the peripheral surface and having an annular groove formed on the inner peripheral surface is arranged, and a ceramic ball bearing is mounted on an inner ring fixed to the shaft and a plane perpendicular to the central axis. And a plurality of balls arranged between the inner and outer wheels and a mating outer ring fitted into the annular groove of the holder, and between at least one end face of the outer ring and a side surface of the annular groove, A bearing device for a hot-dip plating bath in which a spacer made of a metal having a larger thermal expansion coefficient than a metal forming the holder is interposed. 2. A hot-dip galvanizing tank bearing device for supporting a shaft rotatably with respect to a housing via a ceramic ball bearing in a hot-dip galvanizing tank, wherein the outer peripheral surface is inside the housing. A corrosion-resistant material holder having a convex spherical surface that is in sliding contact with the peripheral surface and having an annular groove formed on the inner peripheral surface is arranged, and the ceramic ball bearing is divided into two parts by a plane perpendicular to the central axis. A mating inner ring fitted and fixed to a shaft by a stopper member, an outer ring fitted in an annular groove of the holder, and a plurality of balls arranged between the inner and outer wheels, and at least one of the inner rings A bearing device for a hot-dip plating tank in which a spacer made of a metal having a larger thermal expansion coefficient than a metal forming a shaft is interposed between an end surface and a side surface of a stop member.