RU2788541C1 - Bearing housing for rotating roll, method for cooling bearing housing for rotating roll, machine for continuous casting of steel blanks and method for continuous casting of steel blanks - Google Patents

Abstract

FIELD: bearings.

SUBSTANCE: invention relates to a bearing housing for a rotating roll. The bearing housing has a bearing and sealing units located in it. The cooling jacket is located on the outer periphery of the bearing housing in such a way that the cooling jacket covers at least part of the axial region of the bearing and at least part of the axial region of the seal assembly. The cooling jacket has a cooling water inlet and a cooling water outlet. The bearing housing is cooled by cooling water supplied to the cooling jacket through the cooling water inlet.

EFFECT: efficient cooling of the bearing and stuffing box seal with cooling water over their entire width is achieved.

4 cl, 4 dwg

Description

Technical field

The present invention relates to a bearing housing for a rotating roll used in a high-temperature environment generated by, for example, thermal radiation, such as a bearing housing that supports a back-up roll for a cast slab of a continuous casting machine, while a back-up roll for a cast slab the slab is rotated, and also to the method of cooling the bearing housing of the rotating roll. The present invention also relates to a steel billet casting machine including a rotating roll supported by a bearing housing, and to a steel billet casting machine using the continuous casting machine.

State of the art

In the steel billet continuous casting machine, the molten steel contained in the tundish is poured into a mold, and the cast slab is continuously drawn out of the mold. The cast slab has an outer shell consisting of a solidified shell formed when molten steel poured into the mold comes into contact with the mold and unsolidified molten steel in the interior of the cast slab. The cast slab drawn from the mold is supported by the cast slab backup rolls located under the mold, and the surfaces of the cast slab are cooled by cooling water, whereby the cast slab solidifies towards the center in its thickness direction. The cast slab is then cut to a predetermined length to produce hot rolling material.

The surface temperature of the cast slab in the continuous casting machine is 500° C. or more, and reaches 900° C. or more in the region immediately below the mold. Thus, the bearing housings supporting the cast slab backup rolls as they rotate are exposed to a high temperature atmosphere, and there is a risk of damage to the bearings due to rupture of the oil packings to seal the lubricating oil in the bearing housings. Thus, the rupture of the oil packings leads to a violation of the rotation of the back-up rolls of the cast slab. When the backup rolls for the cast slab cannot be rotated, there is a possibility that the surface of the cast slab will have defects, segregation along the center line in the cast slab will increase, or the cast slab will break through. If the roller bearing of the conveyor roller located in the downstream section of the continuous casting machine is damaged, the cast slab cannot be delivered and the continuous casting operation must be stopped.

Accordingly, methods have been proposed for cooling the bearing housing to prevent damage to the bearing located therein. For example, Patent Literature Document 1 proposes a method for cooling a bearing housing by forming a plurality of cooling water grooves on an outer circumferential surface of a shell of a bearing housing portion, placing a cover covering the cooling water grooves, and introducing cooling water through the cooling water grooves covered by the cover.

Patent Literature 2 proposes a method for cooling a bearing housing for a roller table roller included in a continuous casting machine by covering the bearing housing with a jacket having a cooling air inlet and outlet and introducing cooling air into the jacket.

Citation list

Patent Literature

PTL 1: Japanese Patent Unexamined Publication No. 10-274247

PTL 2: Japanese Unexamined Patent Application Publication No. 2003-290891

Disclosure of the essence of the invention

Technical problem

However, the above-described related art has the following problems.

According to the method of Patent Literature 1, a plurality of cooling water grooves are formed on the outer peripheral surface of the casing, and the cooling water grooves are covered with a cover. Therefore, the cooling water grooves can only be formed on the outer peripheral surface of the housing, which can be covered by a cover, and the bearing and the seal cannot be covered with the cooling water grooves over their entire width. Therefore, when the outer periphery of the housing receives heat radiation over its entire area, the bearing and seal cannot be shielded from the heat transmitted to them, and degradation of the lubricating oil or rupture of the oil packing may occur.

According to the method of Patent Literature 2, the bearing and gland seal can be cooled across their entire width by increasing the area in which the cooling air jacket is installed. However, a sufficient cooling effect cannot be obtained because the cooling medium is cooling air.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bearing housing for a rotating roll and a method for cooling a bearing housing for a rotating roll, by which the bearing and the stuffing box can be efficiently cooled with cooling water. It is also an object of the present invention to provide a steel billet continuous casting machine including a rotating roll supported by a bearing housing, and to provide a steel billet continuous casting method using the continuous billet casting machine.

Solution

The essence of the present invention to achieve the above objectives is as follows:

[1] A bearing housing for a rotating roll to support or transport a high-temperature object, the bearing housing contains a bearing and a seal assembly located therein,

wherein the cooling jacket is located on the outer periphery of the bearing housing in such a way that the cooling jacket covers at least part of the axial region of the bearing and at least part of the axial region of the seal assembly,

wherein the cooling jacket has a cooling water inlet and a cooling water outlet, and

wherein the bearing housing is cooled by cooling water supplied to the cooling jacket through the cooling water inlet.

[2] A bearing housing for a rotating roll according to claim [1], characterized in that the part of the cooling jacket located on the outer periphery of the axial region of the sealing assembly is at least partially located on the radially inner side of the part of the cooling jacket located on the outer periphery of the axial bearing area.

[3] A method for cooling a bearing housing of a rotating roll to support or transport a high-temperature object, the bearing housing has a bearing and a seal assembly located therein, the method includes:

placing a cooling jacket on the outer periphery of the bearing housing such that the cooling jacket covers at least a portion of the axial region of the bearing and at least a portion of the axial region of the seal assembly;

cooling the bearing housing by introducing cooling water into the cooling jacket through a cooling water inlet provided in the cooling jacket; and

discharging the cooling water which has cooled the bearing housing through a cooling water outlet provided in the cooling jacket.

[4] The method for cooling the bearing housing of the rotating roll according to [3], characterized in that the part of the cooling jacket located on the outer periphery of the axial region of the sealing assembly is at least partially located on the radially inner side of the part of the cooling jacket located on the outer periphery axial area of the bearing.

[5] A steel billet continuous casting machine in which the cast slab is supported or guided by one or more rotating rolls, each of which is supported by a bearing located in the rotating roll bearing housing according to [1] or [2].

[6] A method for continuous casting of steel billets, including:

continuous casting of a steel slab using a continuous casting machine according to item [5].

Useful effects of the invention

In accordance with the present invention, most of the outer periphery of the bearing housing is covered with cooling water. Thus, the transfer of heat radiation to the bearing and seal assembly can be blocked. Accordingly, even when the rotary roll bearing is used in a high-temperature environment, degradation of the lubricating oil or oil packing can be prevented while the function of the rotary roll bearing can be maintained.

Brief description of the drawings

Fig. 1 shows a schematic view illustrating an example of a back-up roll for a cast slab included in a steel billet continuous casting machine.

Fig. 2 shows an enlarged view of part A in FIG. 1.

Fig. 3 shows a diagram illustrating an example of a bearing housing proposed in Patent Literature 1.

Fig. 4 is a graph showing the result of measuring the temperature of the gland seal portion in the bearing housing adjacent to the side housing, the measurement is made with a jacketed thermocouple during one day of the continuous casting operation.

Implementation of the invention

A bearing housing for a cast slab backup roll included in a continuous casting machine for a steelmaking process in a steel mill will now be described with reference to the accompanying drawings as an example of a bearing housing for a rotating roll for supporting or transporting a high-temperature object according to the present invention. Fig. 1 is a schematic view illustrating an example of a back-up roll for a cast slab included in a continuous casting machine for a steelmaking process. Fig. 2 is an enlarged view of part A in FIG. 1.

A continuous casting machine (not illustrated) for a steelmaking process in which a cast steel slab is produced by continuous casting of molten steel includes cast slab back-up rolls 20 that serve as rotating rolls in a region from a position immediately below the mold to end of the continuous casting machine. Cast slab backup rolls 20, referred to as backup rolls, guide rolls, or pinch rolls, are arranged in the casting direction to face each other with the cast slab 30 disposed therebetween. The cast slab backup roll 20 illustrated in FIG. 1 is used as a guide roll and has a three-piece design including three rolls: an A 21 roll, a B 22 roll, and a C 23 roll.

Bearing housings 1 with bearings mounted therein are located on roll chocks at both ends of each roll, and each bearing housing 1 is fixed to a guide roll segment frame (not illustrated). Thus, roll A 21, roll B 22 and roll C 23 are supported by bearings located in the bearing housings 1 while still in contact with the cast slab 30 and are thus individually rotatable. The cast slab back-up roll 20 illustrated in FIG. 1 is a rotating roll with internal water cooling.

Now, as an example of the structure of the bearing housings 1, the structure of the bearing housing 1 on the left side of the roll A 21 will be described. All bearing housings 1 have the same design.

As illustrated in FIG. 2, a bearing 2 composed of an outer ring 2a, rolls 2b and an inner ring 2c is provided on a chock 21a of roll A 21. A peripheral cover 7 is provided on the outer periphery of the bearing 2. Towards one side surface of the bearing 2 (the side surface not facing the transverse A side cover 8 is attached to the roll section A 21), and a fixed cover 9 is attached to the other side surface (the side surface facing the roll cross section A 21). The peripheral casing 7 is configured to partially cover the side surface of the bearing 2, which faces the cross section of the roll A 21, and the end of the part of the peripheral casing 7, which partially covers the side surface of the bearing 2, faces the fixed casing 9 with a predetermined interval between them.

The oil packing 3 is located next to the bearing 2 at a location that is surrounded by the peripheral casing 7 and the fixed casing 9, with the peripheral casing 7 and the stationary casing 9 facing each other, and a stuffing box seal 5 is formed from the oil packing 3. The oil packing 4 is located side by side. with the bearing 2 at a location which is surrounded by the side cover 8 and the roll chock 21a, and in which the side cover 8 and the roll chock 21a face each other, and a gland seal 6 is formed from the oil packing 4. The bearing 2 is permanently saturated with lubricating oil by means of an oil packing 3 and oil packing 4. In this specification, the structure consists of oil packing 3 and stuffing box 5, and the structure consisting of oil packing 4 and stuffing box 6 is called "seal units".

As described above, the bearing housing 1 includes a bearing 2, a peripheral housing 7, a side housing 8, a stationary housing 9, an oil packing 3, an oil packing 4, a gland seal 5, and a gland seal 6. FIG. 2, reference numeral 20a denotes a water flow passage for roll cooling water that cools the interior of the back-up roll 20 for cast slab, and 24 denotes a device for supplying and discharging roll cooling water.

The bearing housing 1 has a cooling jacket 10 located on the outer periphery of the peripheral housing 7. The cooling jacket 10 covers the area in which the bearing 2, the oil packing 3, the gland seal 5, the oil packing 4 and the gland seal 6 are located. The cooling jacket 10 has a channel 14 for water through which cooling water flows. Although the material of the cooling jacket 10 is not particularly limited, the cooling jacket 10 is preferably made of metal such as stainless steel or carbon steel because the cooling jacket 10 receives heat radiation.

The cooling jacket 10 has a cooling water inlet 11 and a cooling water outlet 12 . The outer periphery of the peripheral case 7 is cooled by cooling water which is introduced from the cooling water supply pipe (not illustrated) through the cooling water inlet 11, causing it to flow through the water passage 14 and out through the cooling water outlet 12. Accordingly, the jacket is structured in such a way that no heat radiation from the cast slab 30 is transmitted to the bearing 2, the oil packing 3, the stuffing box 5, the oil packing 4 and the stuffing box 6.

As illustrated in FIG. 2, in accordance with the cross-sectional shape of the end part of the roll A 21, the cooling jacket 10 is formed in such a way that its part, which closes the axial region of the sealing assembly, consisting of the oil packing 3 and the stuffing box 5, is located on the radially inner side of the part which covers the axial area of the bearing 2.

The cooling water discharged through the cooling water outlet 12 may flow down the outer periphery of the cooling jacket 10 or be discharged into the cooling water outlet pipe (not illustrated). To shield heat radiation from the cast slab 30, cooling water is preferably directed downward along the outer periphery of the cooling jacket 10, whereby the cooling jacket 10 is also cooled from its outer periphery.

In the bearing housing 1 shown in FIG. 2, the cooling jacket 10 extends over the entire axial area of the bearing 2 and over the entire axial area of each seal assembly. However, the cooling jacket 10 is not limited to this shape. In other words, the cooling jacket 10 may be positioned on the outer periphery of the bearing housing 1 such that it extends over at least a portion of the axial region of the bearing 2 and at least a portion of the axial region of each seal assembly.

In the bearing housing 1 illustrated in FIG. 2, the cooling water inlet 11 and the cooling water outlet 12 are directly connected to the cover 13 which forms the outer periphery of the cooling jacket 10. However, the method by which the cooling water inlet 11 and the cooling water outlet 12 are attached to cooling jacket 10 is not limited to this shape. For example, cooling water may instead be supplied and discharged through a water channel formed in the bearing housing 1.

As described above, according to the rotary roller bearing housing and the cooling method of the rotary roller bearing housing of the present invention, a large part of the outer periphery of the bearing housing 1 is covered with cooling water. Thus, the transfer of heat radiation to the bearing 2 and gland seals 5 and 6 can be blocked. Accordingly, even when the bearing 2 is used in a high temperature environment, the destruction of the lubricating oil or the oil packing 3 and 4 can be prevented, while the function of the bearing 2 can be maintained.

In the above description, the present invention is applied to the bearing body 1 of the back-up roll 20 for casting slabs of a continuous casting machine. However, the present invention can be applied to a bearing housing for any rotating roll that is exposed to a high temperature environment such as heat radiation, and the use of the bearing housing is not limited to the present invention. The internal structure of the bearing housing is also not limited to that described above, and the present invention can be applied to any bearing housing in which a so-called "bearing" is located.

Examples

Example 1

A test was conducted in which a bearing housing of a cast slab backup roll (guide roll) of a continuous casting machine for producing a cast steel slab by a continuous casting method was cooled with cooling water. The continuous casting machine used was a vertical bending continuous casting machine with the following specifications: vertical part 3.0 m, 10-point bending (upper bending area), radius of curvature of the curved part 10.5 m, 6-point straightening ( lower straightening zone), the length of the machine is 49.2 m. The continuous casting machine was capable of producing a cast slab with a thickness of 220 mm and a width of 675 mm to 2100 mm. The bearing housing that was tested was a bearing housing for a cast plate backup roll to support a cast slab with a surface temperature of 700°C to 900°C. The bearing housing contained a bearing (rolling bearing) with an outer diameter of 170 mm, an inner diameter of 110 mm and a width of 43 mm.

The test was carried out on a bearing housing according to the present invention, illustrated in FIG. 2, and was also made on the bearing housing proposed in Patent Literature 1 for comparison. The temperatures in the bearing housings were measured during the continuous casting process and then the measured temperatures were compared.

In FIG. 3 illustrates an example of a bearing housing proposed in Patent Literature 1. As shown in FIG. 3, the bearing housing 1A of Patent Literature 1 includes a peripheral casing 7 having a plurality of cooling water grooves 16 at its outer periphery, and the cooling water grooves 16 are covered by a cover 15. Cooling water is caused to flow through the cooling water grooves 16. water covered by the cover 15, whereby the outer periphery of the peripheral housing 7 is cooled with water. Other designs of the bearing housing 1A illustrated in FIG. 3 are similar to the structures of the bearing housing 1 shown in FIG. 2. The same elements are designated by the same reference numerals and their description is omitted.

The bearing housing 1 of the present invention, illustrated in FIG. 2 (hereinafter also referred to as "example of the present invention"), and the bearing housing 1A for comparison illustrated in FIG. 3 (hereinafter also referred to as "prior art example") was cooled by supplying cooling water to each of the water passages 14 and the cooling water grooves 16, respectively, of the bearing body 1 and the bearing body 1A at a water flow rate of 15 liters per minute. For both the bearing housing 1 according to the present invention and the bearing housing 1A according to the example of the prior art, the cooling water used to cool the bearing housing 1 and the bearing housing 1A was directed to flow down the outer peripheries of the bearing housings.

In FIG. 4 shows the result of a measurement in which the temperature of the area of the stuffing box 6 indicated by the letter "P" in FIG. 2 and 3, which is adjacent to the side body 8, was measured with a thermocouple in a protective casing during one day of continuous casting. In FIG. 4, the periods during which the temperature is temporarily reduced are periods between continuous casting operations during which no continuous casting is performed. The other periods are periods during which continuous casting (continuous melt-to-weld casting) of molten steel is carried out.

As illustrated in FIG. 4, according to an example of the present invention, the temperature of the gland seal section 6 during continuous casting is lower by 20-40°C compared to the example from the prior art. Thus, it was confirmed that the effect of heat radiation from the cast slab on the stuffing box 6 can be reduced.

In the example of the prior art, the area in which the gland seal 5 is located is not covered by the cover 15. In contrast, in the example of the present invention, the area in which the gland seal 5 is located is also closed by the cooling jacket 10. Temperatures in these areas were determined by temperature analysis. As a result, it was verified that according to the example of the present invention, the temperature in the area in which the stuffing box 5 is located is lower by about 70-80°C compared to the example of the prior art.

Example 2

The curved vertical type slab continuous casting machine used in Example 1 was used to cast steel into a slab having a surface temperature of 700°C to 900°C. In particular, at 800° C., the cast slab had minimal ductility, in other words, the possibility of surface cracking in the cast slab was high. The width of the cast slab produced was 2100 mm, which was the maximum width for a continuous casting machine. In the lower straightening zone of the slab continuous casting machine, as viewed from the upstream side to the downstream side of the ingot, the bearing housings located near the left end portion of the cast slab in the width direction, each of which consisted of the proposed bearing housing in the patent literature 1 are illustrated in Fig. 3 (bearing housing of the prior art), and the bearing housings located near the right end portion of the cast slab in the width direction, each of which consisted of a bearing housing in accordance with the present invention, are illustrated in FIG. 2. In the lower straightening area of the vertical bending type slab continuous casting machine, there is a possibility that the surfaces of the cast slab will be deformed and cracked.

The bearing housings were positioned as described above, and a level A continuous casting operation was performed in which the amount of secondary cooling water supplied before the cast slab reached the lower straightening zone was controlled so that the surface temperature of the cast slab was in the range of 700°C. - 900°C, including 800°C, at which the likelihood of surface cracking was high. In addition, a level B continuous casting operation was carried out in which the amount of secondary cooling water supplied before the cast slab reached the lower straightening zone was controlled so that the surface temperature of the cast slab was in the range of 900°C to 1000°C at the lower editing zone.

Continuous casting of 10 melts of molten steel with chemical composition [C]: 0.03 to 0.05 wt. %, [Si]: 0.25 to 0.35 wt. %, [Mn]: 1.3 to 1.4 wt. %, [P]: 0 to 0.015 wt. % and [S]: from 0 to 0.002 wt. % was carried out for each level A and level B. The mass of molten steel was 245 tons per melt.

After continuous casting, the surface of the cast slab was ground to a depth of 2 mm over its entire area, and the number of surface cracks (3 mm or more in length) in the cast slab was counted. The cast slab obtained by the level A operation had 3.4 surface cracks in a length of 1 m. In contrast, the cast slab obtained by the level B operation did not have surface cracks of 3 mm or more in length.

The appearance of the bearing housings in the lower straightening zone was observed immediately after the continuous casting test described above. As a result, no abnormalities were found, in particular for bearing housings according to the present invention. In contrast, the prior art bearing housings had surfaces that were discolored due to temperature rise, and some of the bearing housings had flakes formed on the cast slab attached thereto.

List of reference positions

1 bearing housing

1A bearing housing

2 bearing

2a outer ring

2b roll

2c inner ring

3 oil packing

4 oil packing

5 stuffing box

6 gland seal

7 peripheral casing

8 side cover

9 fixed casing

10 cooling jacket

11 cooling water inlet

12 cooling water outlet

13 cover

14 water channel

15 cover

16 cooling water groove

20 backup roll for cast slab

20a flow channel for roller cooling water

21 roll A

21a swath chock A

22V roll B

23 roll C

30 cast slab.

Claims (12)

1. Bearing housing (1) for a rotating roll to support or transport a high-temperature object, wherein the bearing housing (1) contains a bearing (2) and a sealing assembly located therein, at the same time, on the outer periphery of the housing (1) of the bearing, a cooling jacket (10) is located in such a way that it covers at least part of the axial region of the bearing (2) and at least part of the axial region of the sealing assembly, wherein the cooling jacket (10) has an inlet (11) for cooling water and an outlet (12) for cooling water, wherein the bearing housing (1) is configured to be cooled by means of cooling water supplied to the cooling jacket (10) through the inlet (11) for cooling water, characterized in that part of the outer periphery of the cooling jacket (10), located on the outer periphery of the axial region of the sealing assembly, is at least partially located on the radially inner side of the outer periphery of the cooling jacket (10), located on the outer periphery of the axial region of the bearing (2) . 2. A method for cooling a bearing housing (1) for a rotating roll to support or transport a high-temperature object, wherein the bearing housing has a bearing (2) and a seal assembly located therein, the method including: placing a cooling jacket (10) on the outer periphery of the bearing housing (1) so that the cooling jacket (10) covers at least part of the axial region of the bearing (2) and at least part of the axial region of the seal assembly; cooling the bearing housing (1) by introducing cooling water into the cooling jacket (10) through the cooling water inlet (11) provided in the cooling jacket (10); and discharging the cooling water which has cooled the bearing housing (1) through the cooling water outlet (12) provided in the cooling jacket (10), characterized in that part of the outer periphery of the cooling jacket (10), located on the outer periphery of the axial region of the sealing assembly, is at least partially located on the radially inner side of the outer periphery of the cooling jacket (10), located on the outer periphery of the axial region of the bearing (2) . 3. A continuous casting machine in which the cast slab is supported or guided by one or more rotating rolls, each of which is supported by a bearing (2) located in the bearing housing (1) for the rotating roll according to claim 1. 4. A method for continuous casting of steel billets, including continuous casting of a steel slab using a continuous casting machine according to claim 3.

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