JP2000120658A - Supporting structure of sink roll for hot dipping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a supporting structure of a sink roll whose ceramic bearings do not crack even when they are drawn up from a metal bath. SOLUTION: This sink roll 11 to be immersed in a metal bath for hot dipping is supported rotatably through a support member 14 and ceramic bearings installed in a bearing frame made of metal located near the forefront of the support member. This supporting structure 10 is configured so that the area around the forefront of the support member 14 including the bearing frame is kept warm when the roll 11 is not immersed in the metal bath. For keeping warm, one example is such that a warm-keeping cover 40 furnished internally with a solenoid is put on the area around the forefront of the support member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for a sink roll (roll in bath) immersed in a metal bath in a continuous hot-dip galvanizing line for galvanizing or the like.

[0002]

2. Description of the Related Art A hot-dip galvanizing pot 1 and a sink roll 11 as shown in FIG. 4 are used in a continuous galvanizing line for continuously galvanizing long steel plates. The pot 1 is a container for storing molten zinc (or a material to which molten aluminum is added in order to improve the adhesion of zinc to the steel sheet x), and the sink roll 11 is a cylinder for winding the steel sheet x in a U-shape. Roll. The steel sheet x sent out from the upstream reel (not shown) is heat-treated while removing the oxide film in the immediately preceding annealing furnace (not shown), and then the pot 1 is passed through the sink roll 11 as shown in the figure. Zinc bath 2 inside
By passing it through, a zinc coating is adhered to the surface of the steel sheet x. In the same plating line, sink roll 11
In the state where the steel sheet x is supported by the support rolls 21 and 31 above, the plating thickness is adjusted by blowing air from an air knife (not shown), and then the steel sheet x is cooled and the downstream reel ( (Not shown). The “sink roll” is generally a roll 1 at the bottom in FIG.
1, the support rolls 21 and 31 which support the steel plate x on the upper part thereof are also sink rolls in a broad sense.

As shown in FIG. 5, a sink roll 11 is supported by two support members 14 on shafts 12 at both ends. If the sink roll 11 does not rotate, the fed steel plate x and the surface of the sink roll 11 rub against each other, and the surface of the steel plate x is scratched. Is rotatably supported through it. The bearing 17 is held inside a metal bearing frame (in the case of FIG. 5, a cylindrical bush) 16, and inside the bearing 17, a shaft 12 of the sink roll 11 is provided.
Is rotatably supported.

The above-described bearing 17 for supporting the sink roll 11
Of these, ceramics are often used. Zinc bath 2 at about 400 ° C and in a molten state
(FIG. 4), the bearing 17 has
This is because it is necessary to have considerable heat resistance, abrasion resistance, erosion resistance and the like and to have excellent durability. The support structure 10 of the sink roll 11 using the ceramic bearing 17 as described above is described in, for example, Japanese Patent Application Laid-Open No. 2-153055.

[0005]

[0007] Ceramic materials inherently have a weak point that they have low toughness and are easily cracked as compared with metals. Therefore, the above-mentioned ceramic bearing used for the support structure of the sink roll often breaks when it is immersed in a zinc bath and then pulled up. The reason that the bearing is easily damaged is as follows.

This is because molten zinc infiltrates between the inner peripheral surface of the bearing frame and the outer peripheral surface of the bearing while the bearing is immersed in the zinc bath together with the sink roll. When aluminum is contained in the molten zinc as described above, the infiltration is particularly likely to occur because the permeability of the molten metal increases. The molten zinc that has entered between the bearing frame and bearings solidifies when the sink roll is pulled up and the temperature drops, resulting in an increase in volume,
The ceramic bearing is pressed inward causing cracking.

(B) When the temperature of the sink roll is lowered by being pulled up from the zinc bath, the outer bearing frame contracts more than the bearing and exerts a strong tightening force on the bearing. Ceramics that can be used as the bearings described above generally have a smaller coefficient of thermal expansion than metals, and therefore do not shrink in diameter as much as metals when the temperature drops. For this reason, when the temperature of a bearing is reduced by mounting the bearing in a tight fit in the bearing frame, or when zinc enters between the bearing frame and the bearing and solidifies, tightening due to shrinkage of the bearing frame The force acts strongly on the bearing and damages the bearing. In the above-mentioned publication, it is proposed to provide an alignment mechanism and a packing material inside the bearing frame, but there is a metal bearing frame outside the ceramic bearing, and there is a possibility that zinc enters between the two and solidifies. For some reason, it is difficult to completely prevent bearing damage.

It is an object of the present invention to provide a sink roll supporting structure in which a ceramic bearing is not broken when it is pulled out of a bath.

[0009]

According to a first aspect of the present invention, there is provided a support structure for a sink roll for hot-dip plating, comprising a sink member immersed in a metal bath for hot-dip plating, a support member and a metal bearing near its tip. It is a support structure that rotatably supports via a ceramic bearing provided in the frame, but when the sink roll is not immersed in the metal bath, the vicinity of the tip of the support member including the above-mentioned bearing frame is It is characterized in that it can be kept warm.

With such a support structure, when the sink roll is pulled up from the high-temperature metal bath, the vicinity of the tip of the support member is kept warm, so that the metal bearing frame and the bearing frame and the bearing are infiltrated between the bearing and the bearing. The temperature of the melted metal can be prevented from lowering. When the temperature of the metal bearing frame is prevented from lowering, the bearing frame does not thermally shrink. Therefore, even if there is a difference in the coefficient of thermal expansion between the bearing frame and the inner ceramic bearing as described above, tightening is performed. No force acts on the bearing. Also, if the molten metal that has entered between the bearing frame and the bearing can be kept from solidifying, regardless of the solidification characteristics (volume change rate) of the metal,
The metal is prevented from exerting an inward force on the bearing.

Therefore, if the vicinity of the tip of the support member is kept warm when the sink roll is pulled up from the metal bath, breakage of the ceramic bearing due to immersion and pulling up in the bath is prevented. Ceramic bearings are generally more expensive in terms of material and processing costs than metallic ones, and thus preventing damage to the bearing will significantly reduce the cost of hot-dip plating. .

The support structure according to the second aspect is characterized in that a heat insulating cover including a heating element (such as an electric heater or a gas burner) or an electromagnetic induction coil can be attached and detached particularly near the tip of the support member. And

The heat retaining cover referred to here can be attached and detached near the tip of the support member. Therefore, when the sink roll (and the support member) is pulled up from the metal bath, it is attached to function to function. It is possible to keep the vicinity of the tip warm and prevent the ceramic bearing from being damaged as described above. The heating element generates heat by itself and transfers it to keep the bearing frame warm, and the electromagnetic induction coil generates an induced current in the conductor by the change in the magnetic flux generated by itself, and the heat (Joule heat) generated Keep the bearing frame etc. warm.

Since the heat insulating cover can be removed when the sink roll is immersed in the metal bath, it is easy to prevent the heat insulating cover from being immersed in the bath and being damaged or broken. In addition, sink roll and its axis,
Bearing frames, support members, etc. have a considerable heat capacity, and the temperature does not drop immediately even if the temperature is not kept at all when pulled out of the metal bath. It will not be done.

[0015] The support structure according to a third aspect is characterized in that a heating element or an electromagnetic induction coil is built in near the tip of the support member.

If a heating element or an electromagnetic induction coil is built in near the tip of the support member, when the sink roll (and the support member) is pulled up from the metal bath, they function to keep the bearing frame and the like warm. As described above, it is possible to prevent the ceramic bearing from being damaged. The functions of the heating element and the electromagnetic induction coil are the same as those of the above-described heat insulating cover. In this support structure, since the heating element and the coil are built in the support member so that they do not come into contact with the molten metal, they are removed even when the sink roll is immersed in the metal bath. No need.

In addition to the above features, the support structure according to the fourth aspect of the present invention has the following features: 1) an interference fit inside the metal bearing frame at a temperature when immersed in a metal bath; The above-mentioned ceramic bearing is mounted so that the fitting part has an appropriate interference fit without permanent deformation or damage). 2) Inside the bearing, from inside a metal bath The metal shaft of the sink roll is supported by a clearance fit having a clearance such that the molten metal flows out when pulled up.

Since the shaft (metal shaft) of the sink roll is passed through the inside of the ceramic bearing as shown in FIG. 5, depending on the relationship between the two, the above-mentioned heat retention is strictly controlled so as to fall within a narrow temperature range. In some cases, it must be controlled. Metals have a higher coefficient of thermal expansion than ceramics, so if the temperature of the metal shaft rises due to excessive heat retention, the thermal expansion may damage the ceramic bearings by receiving force from the inside. is there. However, this claim 4
In the above support structure, since the clearance between the bearing and the metal shaft is fitted through a large clearance as described in 2) above, the temperature of the metal shaft may be increased significantly even if it is large. Therefore, it is sufficient to keep the above-described support members and the like warm in a rough temperature range. If you don't need high precision in the warming temperature,
High-grade control equipment is not required, and the attention and the amount of work required for the operator and the like are small, so that the required cost is reduced.

Since the clearance between the bearing and the metal shaft is set as described in the above item 2), in this supporting structure of the fourth aspect, the sink roll can be easily replaced. Because the gap between the bearing and the metal shaft is a clearance fit, and the gap is large, the molten metal flows out of the metal bath when it is pulled up from the metal bath. This does not cause a situation in which the metal solidifies and hinders the metal shaft from being pulled out. If the surface of the sink roll becomes rough due to long-term use, it is necessary to re-polish the surface, and thus such easy replacement has great significance in terms of cost and efficiency.

In this support structure, since the bearing is mounted in the bearing frame so as to be an interference fit at the temperature when it is immersed in the metal bath as described in 1), replacement of the ceramic bearing is not difficult. . The reason why the bearing can be easily replaced due to such fitting is as follows. That is, a) Since the fitting is performed so that the interference fits at the temperature during use, there is no need to arrange a retainer member such as a nut or a retaining ring for the purpose of preventing the bearing from coming off the bearing frame during use. As long as the retainer member is not placed, it is not necessary to remove and reattach the bearing when replacing the bearing.After the deteriorated bearing is split and pulled out, the new bearing is placed in the bearing frame at room temperature. It is enough to insert it. In addition, it is easy to insert a new bearing at room temperature as in (b) because the bearing frame is pulled up from the metal bath (or kept warm afterwards) and the inside diameter is large because it is in a high temperature state. . Then, if the temperature of the bearings is raised by performing the above-mentioned heat retention (or if the bearings are immersed together with the sink roll in a metal bath), the new bearing and the bearing frame are tightly fitted. be able to. Ceramic bearings
Although the above-mentioned heat retention prevents damage, it is used under severe conditions and deteriorates and wears earlier than other parts. Therefore, easy replacement is still important.

[0021]

1 to 5 show an embodiment of the present invention. All are drawings of the support structure 10 of the sink roll 11 provided in the continuous hot-dip galvanizing line for steel sheets, and each of FIGS.
4 shows a supporting structure 10 including a heat retaining means in the vicinity of the front end of the support structure 4. FIGS. 4 and 5 are used for the description above, and are a side view of the sink roll 11 and the like when used in the zinc bath 2 of the pot 1 and a detailed view of the support structure 10, respectively. .

The support structure 10 rotatably supports the sink roll 11 with the two support members 14 as described above with reference to FIG. Sink roll 11
Has a metal shaft 12 at both ends of a main body portion around which a steel plate x is wound (see FIG. 4), and a support member 14 supports the outer periphery of the shaft 12 via a ceramic bearing 17.

The two support members 14 are arranged under the frame 13 provided so as to be able to move up and down so that the distance between them can be changed. Details of the vicinity of the tip supporting the shaft 12 are as follows. is there. That is, a) An annular bearing frame (sleeve) 16 made of stainless steel is fixed near the tip of the support member 14. In other words, as shown in FIG. 5B, the divided piece 1 is placed near the tip of the support member 14 with the graphite packing 15 interposed therebetween.
4a are integrated by bolts 14b, and the bearing frame 16 is held inside by the bolts 14b. The bearing frame 16 may be fixed near the tip of the support member 14 by welding or the like.
And the bolt 14b, it is easy to cope with an emergency in which the shaft 12 of the sink roll 11 cannot be pulled out of the support member 14. Further, it is also preferable in that the effect of the graphite packing 15 reduces the impact acting on the bearing 17.

B) Inside the bearing frame 16, a cylindrical ceramic plain bearing 17 having a fitting dimension determined so as to have a tight fit during use is mounted. The term “in use” means that the sink roll 11 and its bearings 17 are immersed in the zinc bath 2 as shown in FIG. 4, and in this case, the immersed components are brought to the temperature of the zinc bath 2 (around 400 ° C.). Get closer. If the interference fit is made at room temperature, a gap is formed between the ceramic and metal used at high temperatures based on the difference in thermal expansion between the two (the former has a smaller coefficient of thermal expansion than that of the latter). However, another component is required to prevent the bearing 17 from coming off from the bearing frame 16, which is not preferable.

C) On the inside of the bearing 17, about 1 per radius
The metal shaft 12 is inserted into the sink roll 11 such that a gap of about 2 mm (about 2 mm in diameter difference) is formed. When such a large gap is provided between the bearing 17 and the shaft 12, the molten zinc in the gap easily flows out. Thus, no excessive force is applied to the bearing 17 from the shaft 12. In addition, if there is such a gap, the shaft 12 can be easily extracted from the bearing 17 by widening the interval between the two support members 14, and the sink roll 1
1 can be easily and quickly exchanged.

With respect to the support structure 10 constructed as described above, the pot 1 (zinc bath 2) shown in FIG.
Is raised, the vicinity of the tip of the support member 14 is kept at about 400 ° C., which is equal to the temperature during immersion. The inside of the bearing frame 16 shown in FIG.
The bearing 17 is mounted by interference fit as described above, and between the two, molten zinc or molten aluminum (zinc bath 2)
When the surrounding temperature decreases, the difference in shrinkage during cooling between the bearing frame 16 and the bearing 17 and solidification of the molten metal cause the ceramic bearing 17 to face inward. This is because there is a risk of breaking under the power of

In order to keep the temperature of the vicinity of the tip of the support member 14, any one of the means shown in FIGS.
The configuration and operation of the heat retaining means in each figure are as follows.

First, the heat retaining means shown in FIG. 1 is a heat retaining cover 40 containing an electromagnetic induction coil (not shown). FIG.
1B, the vicinity of the tip of the support member 14 can be inserted inside as shown in FIG. 1A, and the shaft 12 of the sink roll 11 (see FIG. 5) need not be removed at that time.
As described in the above, it is finished in a box shape including the hollow portion 41 and the groove 42.

When the sink roll 11 is pulled out of the zinc bath 2 together with the support member 14 and the like, this heat retaining cover 40 is attached so as to cover the tip of the support member 14 from the tip of the support member 14 as shown in FIG. AC power is supplied to the electromagnetic induction coil via a cable (not shown). Due to the change in magnetic flux generated by the coil, an induced current is generated in the vicinity of the tip of the support member 14 as a conductor or in the bearing frame 16 (FIG. 5), and the vicinity is kept warm by Joule heat. Since the groove 40 is formed in the cover 40, the shaft 12 can be pulled out of the bearing 17 and replaced again to replace the sink roll 11 while keeping the temperature in this manner. If it is necessary to prevent the cover 40 itself from generating heat, the cover 40 may be made of a non-conductive material. The temperature of the bearing frame 16 is adjusted to about 400 ° C. as described above by increasing or decreasing the supplied power. And, of course, sink roll 11 in zinc bath 2
Immediately before immersion in the heat insulating cover 40, the support member 1
Remove from the end of 4.

FIG. 2 shows a heat insulating cover 50 made of a heat-resistant blanket in which an electric heater 53 is disposed inside.
As shown in FIG. 2B, the cover 50 also has a hollow portion 51 for inserting the vicinity of the tip of the support member 14 and a shaft 1.
2 (FIG. 5) are formed. Since it is made of a blanket, it is excellent in heat insulation and it is difficult for internal heat to escape to the outside. In addition, when it is attached to the support member 14, it can be easily deformed as needed.

The heat insulating cover 50 is also used for the sink roll 11.
2 is attached near the tip of the support member 14 as shown in FIG. 2A, and the heater 53 is energized from a power supply cable (not shown). Heater 5
By transmitting the heat generated by 3, the vicinity of the tip of the support member 14 and the bearing frame 16 (FIG. 5) are kept warm. That the sink roll 11 can be replaced while keeping the temperature warm,
The fact that the calorific value can be adjusted by increasing or decreasing the supplied power and that the heat retaining cover 50 should be removed when immersed in the zinc bath 2 are the same as in the case of the heat retaining cover 40 in FIG.

FIG. 3 shows an example in which the electromagnetic induction coil 60 is built in the vicinity of the tip of the support member 14. When the sink roll 11 is lifted out of the zinc bath 2, AC power is supplied to the coil 60 from a power supply cable (not shown) that passes through the inside of the support member. This keeps the bearing frame 16 and the like warm and prevents the ceramic bearing 17 from breaking. The coil 60 can be replaced with an electric heater or the like.

In the example of FIG. 3, a means for keeping heat is built in the support member 14 so that molten zinc does not enter the support member 14 even when the vicinity of the tip is immersed in the zinc bath 2. Make up. Therefore, when the sink roll 11 is immersed in the zinc bath 2, the support member 14
There is no need to remove any equipment or parts from the equipment. If the output of the electromagnetic induction coil can be considerably increased while the sink roll 11 and the vicinity of the tip of the support member 14 are immersed in the zinc bath 2, the zinc bath 2 is kept warm by the coil and the temperature is adjusted. It is also possible to do.

Although the embodiments of the present invention have been described above, the present invention is not limited to the sink roll 11 shown in FIG. The support roll 21 in FIG.
As long as each of the support members 31 is supported via a ceramic bearing before the support members 24 and 34, the invention can be applied to them as in the above-described embodiment. Further, the case where the sink roll 11 is immersed in a molten zinc bath for galvanizing has been described above. However, in order to perform plating of tin (tin) or aluminum instead of zinc plating, molten tin or molten aluminum or the like is used. It is of course possible to implement the invention as a support structure for a sink roll immersed in a metal bath.

[0035]

According to the support structure of the sink roll for hot-dip plating according to the first aspect of the present invention, it is possible to prevent the ceramic bearing from being damaged due to the sink roll being immersed in the bath and pulled up. Since ceramic bearings are generally expensive, this can significantly reduce the cost of hot-dip plating.

In the support structure according to the second aspect, the effect described in the first aspect can be obtained by using a detachable heat insulating cover.

With the support structure according to the third aspect, it is not necessary to attach or remove equipment or components for keeping heat when the sink roll is immersed or pulled up.

According to the fourth aspect of the present invention, since a sufficient clearance is provided between the ceramic bearing and the metal shaft, first, even if the temperature is excessively maintained, the bearing cannot be forced from the inside. It is only necessary to keep the temperature in a rough temperature range because no excessive force acts, and high-grade control equipment is not required, and the work load on the operator and the like is reduced. Further, since there is a large gap between the bearing and the metal shaft, it is possible to easily replace the sink roll. Since there is no need to provide any retainer member for the purpose of preventing the bearing from falling out of the bearing frame during use, it is easy to replace the bearing.

[Brief description of the drawings]

FIG. 1 shows a support member 14 of a support structure 10 of a hot-dip galvanizing sink roll 11 as an embodiment of the present invention.
5 is a drawing in the case where a heat retaining cover 40 is attached near the tip of the diaper. FIG. 1A is a perspective view showing an attached state of a cover 40, and FIG. 1B is a perspective view showing a detached state.

FIG. 2 is a view showing a heat insulating cover 50 and the like as another embodiment different from FIG. 1; FIG. 1A is a perspective view showing an attached state, and FIG. 1B is a perspective view showing a detached state.

FIG. 3 is a perspective view showing, as another embodiment different from FIGS. 1 and 3, an example in which a means for keeping heat is built in a support member 14. FIG.

4 is a side view of the support structure 10 and the sink roll 11, showing a state in which the sink roll 11 is immersed in the zinc bath 2 of the pot 1. FIG.

FIG. 5 is a detailed view of the support structure 10;
FIG. 5A is a front view (a view taken along the line VV in FIG. 4), and FIG.
(B) is a bb arrow view in (a).

[Explanation of symbols]

 Reference Signs List 1 pot 2 zinc bath (metal bath) 10 support structure 11 sink roll 12 metal shaft 14 support member 16 bearing frame 17 bearing 40/50 heat retaining cover 60 electromagnetic induction coil

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[Procedure amendment]

[Submission date] October 22, 1999 (1999.10.
22)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

According to a first aspect of the present invention, there is provided a support structure for a sink roll for hot-dip plating, wherein the sink roll dipped in a metal bath for hot-dip plating and pulled up from the support member and a tip thereof. It is a support structure that rotatably supports via a ceramic bearing provided in a nearby metal bearing frame, but when the sink roll is not immersed in the metal bath, the support including the above-described bearing frame is provided. It is characterized in that the vicinity of the tip of the member can be kept warm.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J103 AA02 BA04 BA05 CA25 FA26 GA02 GA52 HA08 HA51 4K027 AB42 AD17

Claims (4)

[Claims] 1. A supporting structure for rotatably supporting a sink roll immersed in a metal bath for hot-dip plating via a support member and a ceramic bearing provided in a metal bearing frame near the tip thereof. A support structure for a sink roll for hot-dip plating, wherein the vicinity of the tip of the support member including the bearing frame can be kept warm when the sink roll is not immersed in the metal bath. 2. The support structure for a hot-dip plating sink roll according to claim 1, wherein a heat retaining cover including a heating element or an electromagnetic induction coil can be attached and detached near a tip of the support member. 3. The support structure for a hot-dip plating sink roll according to claim 1, wherein a heating element or an electromagnetic induction coil is built in the vicinity of the tip of the support member. 4. The above-mentioned ceramic bearing is mounted inside the above-mentioned metal bearing frame so as to have an interference fit at a temperature when immersed in a metal bath. The hot-dip plating according to any one of claims 1 to 3, wherein the metal shaft of the sink roll is supported by a clearance fit having a clearance such that the molten metal flows out when pulled up from the metal bath. Structure for sink rolls.