JPH07268581A - Roller bearing device in molten metal plating bath and bearing wear prevention method - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent wear due to direct contact between the shaft and bearing and to extend the life of the bearing. [Structure] In a bearing device for rolls 4 and 5 arranged in a molten metal plating bath 1 in a dipped state, a slide bearing 11 that supports the rolls 4 and 5 is provided with a liquid ejection hole 11a that is opened in its inner peripheral surface. . An external molten metal tank 13 for supplying the molten metal 14 to supply the molten metal 14 having a temperature lower than that of the plating bath 1 and its supply means 15 are provided to the liquid ejection hole 11a, and further, a sliding bearing 11 part and a roll 4 A thermometer 18 for measuring the temperature of the molten metal in contact with the shaft portion 12 of No. 5 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll bearing device used in a state of being immersed in a molten metal plating bath and a method for preventing wear of the bearing.

When forming a plating layer of another metal on the surface of a steel strip, in addition to plating by an electrochemical treatment, steel is placed in a plating bath 1 in which a metal to be plated is melted as shown in FIG. A so-called hot dip metal plating process of immersing the strip 2 is widely practiced. In such molten metal plating, the steel strip 2 guided from the continuous furnace 8 through the snout 9 to the plating tank 3 is turned by the sink roll 4 and then exits from the plating tank 3 through the support roll 5. .

By the way, as shown in FIG. 7, the sink roll 4 and the support roll 5 for guiding the steel strip 2 in the high-temperature plating bath 1 are provided with rolling bearings 7 and a bearing 7 installed at the tip of the support arm 6, respectively. Although it is rotatably supported by a sliding bearing, since a bearing used in such a high temperature plating bath 1 is required to have heat resistance, wear resistance, etc., a rolling bearing made of ceramics has been proposed. (Japanese Utility Model Publication No. 61-90852).

On the other hand, the sliding bearing has been conventionally made of heat-resistant steel, but since it is constantly immersed in a molten metal bath under a high temperature of 450 to 500 ° C., it is severely damaged. In particular, when the amount of wear of the bearing becomes large, the roll fails to rotate, the steel strip passing through the roll flaps, and the amount of molten metal deposited becomes uneven. Therefore, the bearings have to be replaced in a short period of time, and there have been problems such as a decrease in production amount due to the line stoppage and an increase in repair costs.

Therefore, in order to prevent wear of the sliding bearing, in a bearing supporting a roll shaft arranged in a hot dip bath, a liquid jet hole is formed inside the roll shaft facing the roll shaft and jetted from the liquid jet hole. One that supports a roll with a liquid (Japanese Patent Laid-Open No. 3-115552) or a supply hole for a molten plating solution that is opened in the inner peripheral surface of a bearing member, and between the supply hole and the inner peripheral surface of the bearing member during plating. Supplying a hot-dip plating solution as a lubricant to the
No. 106557) has been proposed.

[0006]

However, since all of the above-mentioned proposals supply the plating solution having the same temperature as that of the hot dipping bath, the viscosity of the plating solution is as small as that of the hot dipping bath, and the roll supporting The effect and the effect of preventing wear of the bearing member are not sufficient.

According to the present invention, a molten metal plating solution having the same composition as the molten metal plating bath and a high viscosity is supplied as a lubricant to the bearing sliding portion to solve the above-mentioned conventional problems. An object of the present invention is to provide a bearing device for a roll in a bath and a method for preventing bearing wear.

[0008]

In order to achieve the above object, a roller bearing device for a roll in a molten metal plating bath according to the present invention is a sliding bearing for supporting a roll placed in a molten metal plating bath in a dipped state. In addition to providing a liquid ejection hole to be opened on the inner peripheral surface thereof, an external molten metal tank for supplying the molten metal into the liquid ejection hole so as to supply a molten metal at a temperature lower than that of the plating bath and a supply means therefor, Furthermore, the sliding bearing portion and / or the roll shaft portion is provided with a temperature measuring device for measuring the temperature of the molten metal in contact therewith.

The roll wear in the molten metal plating bath according to the present invention is also provided with a liquid jet hole provided on the inner peripheral surface of a sliding bearing for supporting the roll placed in the molten metal plating bath in a dipped state. , Supplying a molten metal having a temperature of 10 ° C. or more lower than the plating bath temperature from an external molten metal bath, and measuring the molten metal temperature in contact with the sliding bearing portion supporting the roll and / or the roll shaft portion, and the measured temperature Based on
The temperature of the molten metal supplied from the external molten metal tank to the liquid ejection holes provided on the inner peripheral surface of the sliding bearing is controlled.

[0010]

[Function] Since the bearing placed in the molten metal (zinc) plating bath in an immersed state is constantly immersed in the molten plating bath at a high temperature of 450 to 500 ° C., the bearing is severely damaged. The wear of the sliding parts is particularly large. This is largely because the molten metal having a low viscosity of about 3.0 cP serves as a lubricant for the bearing, and the shaft portion of the roll and the bearing are constantly in contact with each other.

Therefore, if the viscosity of the molten metal acting as a lubricant in the bearing sliding portion is increased, the load capacity of the bearing is increased, so that the lubricant can support the shaft portion. If the bearing can be supported by a lubricant, the shaft and the bearing will be in non-contact with each other, so that wear of the bearing can be prevented. In order to increase the viscosity of the lubricant of the molten metal, the temperature of the molten metal may be lowered, but the temperature of the molten metal plating bath needs to be maintained at the temperature determined from the plating conditions of the steel strip. Only the temperature of the molten metal in the sliding parts of the bearing must be lower than the ambient temperature.

In the present invention, a slide bearing for supporting a roll placed in a molten metal plating bath in a dipped state is provided with a liquid jet hole which is opened on the inner peripheral surface thereof, and the liquid jet hole is provided with a liquid jet hole from the plating bath. Since the supply means for supplying the low temperature molten metal from the external molten metal tank is provided, only the molten metal temperature of the bearing sliding portion can be made lower than the ambient temperature.

Further, in the present invention, since the temperature measuring device for measuring the temperature of the molten metal in contact with the sliding bearing portion and / or the roll shaft portion is provided, the temperature of the molten metal supplied from the external molten metal tank is optimized. Can be controlled.

In the present invention, the temperature of the molten metal supplied from the external molten metal tank is set to be lower than the plating bath temperature by 10 ° C. or lower. When the temperature is lower than 10 ° C., the effect of preventing wear of the bearing for supporting the shaft of the roll is small. Because.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in FIGS. 1 is an explanatory view of an embodiment of the present invention corresponding to claims 1 and 3, FIG. 2 is a sectional view taken along line BB of FIG. 1, and FIG.
Is a diagram showing the result of an experiment using the apparatus shown in FIG. 1 to confirm the effect of the apparatus of the present invention corresponding to claim 1, and FIG. 4 is another embodiment of both side surfaces of the sliding bearing in FIG. FIG. 5 is an explanatory view of an embodiment of the present invention corresponding to claims 2 and 4.

In FIGS. 1 and 2, reference numeral 11 denotes a slide bearing for supporting a shaft portion 12 of a roll (for example, sink roll 4 or support roll 5) arranged in the molten metal plating bath 1 in a dipped state. A liquid ejection hole 11a is provided which penetrates from the side surface on the opposite side to the inner peripheral surface at, for example, four equal positions as shown in FIG.

Numeral 13 has the same composition as the plating bath 1 and has a viscosity higher than that of the plating bath 1 because of its low temperature. Further, for example, an external molten metal containing a molten metal 14 containing about 0.15% by weight of Al in molten zinc. The external molten metal bath 13
The molten metal 14 in the inside is, for example, a pump 15a and a pipe 15b.
The sliding bearing 1 by the supply means 15 composed of
It is adapted to be supplied to the first liquid ejection hole 11a.

The bearing device for the roll in the molten metal plating bath of the present invention corresponding to claim 1 has the structure as described above, and using this device, the molten metal 14 having a temperature lower than the temperature of the plating bath 1 by 10 ° C. or more is used. Is supplied from the external molten metal tank 13 to the liquid ejection holes 11a of the sliding bearing 11 according to the third aspect of the present invention.

In order to confirm the effects of the present invention as set forth in claims 1 and 3, the thickness is 0.3 to 2.3 mm and the width is 600.
A steel strip 2 of ˜1450 mm was continuously hot-dip galvanized at a maximum line speed of 180 m / min. At this time, when the molten zinc is not supplied to the liquid ejection holes 11a of the sliding bearing 11, and when the molten zinc plating bath 1 has the same components and the same 460 ° C.
Experiments were carried out for three cases, that is, the case of supplying the molten zinc of No. 1 and the case of supplying the molten zinc of 422 ° C., which has the same composition as that of the hot dip galvanizing bath 1 and is 38 ° C. lower than the bath temperature.

As a result, the liquid ejection hole 11 of the sliding bearing 11
When the molten zinc was not supplied to a, the sliding bearing 11 became unusable after 10 days. FIG. 3 shows the result of examining the wear amount of the sliding bearing 11 after plating for 25 days when the remaining molten zinc was supplied.
When the molten zinc at ℃ was supplied, the amount of wear was about 1/10 that when the molten zinc at 460 ° C was supplied.

The bearing device for the roll in the molten metal plating bath according to claim 1 is not limited to the structure as shown in FIG. 1, and as shown in FIG. 4, for example, Si ₃ N is provided on the roll side of the sliding bearing 11. _The seal plate 17a containing the mechanical seal 16 of ₄ and the seal plate 17b covering the side surface of the slide bearing 11 on the side opposite to the roll of the slide bearing 11 are hermetically sealed to circulate molten metal having a high viscosity at low temperature. It may be

The apparatus shown in FIG. 5 constitutes a bearing device for a roll in a molten metal plating bath corresponding to claim 1 shown in FIG.
8 is provided so that the molten metal temperature of this portion can be measured, and the temperature measured by this thermometer 18 is controlled by the controller 19
So that the molten metal 14 supplied from the external molten metal tank 13 to the liquid ejection hole 11a of the sliding bearing 11 via the supply means 15 by the controller 19 can be controlled to a temperature at which the molten metal 14 has a predetermined viscosity. It is composed. Reference numeral 20 in FIG. 5 is a heater for controlling the temperature of the molten metal 14 to a required temperature by a signal from the controller 19.

In the embodiment shown in FIG. 5, the thermometer 18 is installed on the sliding bearing 11, but the thermometer 18 may also be installed on the roll shaft 12 supported by the sliding bearing 11. You may install in both. Similarly, the heater 20 for the molten metal 14 is connected to the pipe 15b of the supply means 15.
Although it is shown installed in the section, it may be installed in the external molten metal tank 13.

[0024]

As described above, in the present invention, since the shaft can be held by the molten metal having a temperature lower than that of the plating bath, wear due to direct contact between the shaft and the bearing can be prevented, and the life of the bearing can be extended.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention corresponding to claims 1 and 3.

FIG. 2 is a sectional view taken along line BB in FIG.

FIG. 3 is a diagram showing a result when an experiment was performed using the apparatus shown in FIG. 1 in order to confirm the effect of the apparatus of the present invention corresponding to claim 1.

FIG. 4 is a view showing another embodiment of both side surfaces of the sliding bearing in FIG.

FIG. 5 is an explanatory diagram of an embodiment of the present invention corresponding to claims 2 and 4.

FIG. 6 is a schematic explanatory view of a conventional facility in a hot dip metal plating bath.

7 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating bath 4 Sink roll 5 Support roll 11 Sliding bearing 11a Liquid ejection hole 12 Shaft part 13 External molten metal tank 14 Molten metal 15 Supply means 18 Thermometer 19 Controller 20 Heater

Claims (4)

[Claims] 1. A bearing device for a roll placed in a molten metal plating bath in an immersion state, wherein a slide bearing for supporting the roll is provided with a liquid jet hole formed in its inner peripheral surface, and the liquid jet hole is provided. A bearing device for a roll in a molten metal plating bath, comprising: an external molten metal tank for containing the molten metal and a supply means for supplying the molten metal at a lower temperature than the plating bath. 2. The sliding bearing portion and / or the roll shaft portion,
The bearing device for the roll in the molten metal plating bath according to claim 1, further comprising a temperature measuring device that measures the temperature of the molten metal in contact with the roller. 3. A method of preventing wear of a roll bearing placed in a molten metal plating bath in a state of being immersed, in which a liquid jet hole provided in an inner peripheral surface of a sliding bearing for supporting the roll has a temperature higher than that of the plating bath temperature. A method for preventing bearing wear of a roll in a molten metal plating bath, comprising supplying molten metal at a temperature of 10 ° C. or higher at a low temperature from an external molten metal bath. 4. A method of preventing wear of a roll bearing placed in a molten metal plating bath in a state of being immersed, in which a temperature of molten metal in contact with a sliding bearing portion supporting the roll and / or a roll shaft portion is measured, Based on the measured temperature,
A method for preventing wear of a bearing in a roll in a molten metal plating bath, which comprises controlling the temperature of molten metal supplied from an external molten metal bath to a liquid ejection hole provided on the inner peripheral surface of a sliding bearing.