JP2007177860A - Sealing device of bearing casing for hearth roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device of a bearing casing for a hearth roll capable of maintaining sealing performance of the bearing casing of the hearth roll for a long time and capable of smoothly permitting thermal expansion of the hearth roll. <P>SOLUTION: A seal lip 5a of a seal member 5 slidably brought into contact with a neck part 2a of the hearth roll 2 is pushed by a ring shaped spring 5b from a back surface side in order to enhance sealing performance of the bearing casing 3, a tip 5c made of tetrafluoroethylene resin exhibiting excellent abrasion resistance and excellent heat resistance and having a small friction coefficient is stuck to a slide contact part with the neck part 2a of the seal lip 5a, the seal lip 5a is prevented from being worn even when the seal lip 5a is slidably brought into contact with the neck part 2a at a high temperature with a large contact pressure, and sealing performance of the bearing casing 3 can be maintained for a long time, slide contact resistance of the neck part 2a and the seal lip 5a in an axial direction by the thermal expansion of the hearth roll 2 is reduced, and the thermal expansion of the hearth roll 2 can be smoothly permitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealing device for a hearth roll bearing box that seals a bearing box that supports a neck portion of the hearth roll.

  In the hearth roll of a continuous annealing furnace, a body part around which a steel strip to be continuously annealed is wound is passed into the furnace, and the neck part is supported by a bearing box outside the furnace. This hearth roll is long and has a length of several meters, and a large bending is generated by a bending moment applied from a steel strip or the like. Therefore, a rolling bearing with a centering function is incorporated in a bearing box that supports the neck portion. Since the outside of the continuous annealing furnace is an environment where dust is present, the bearing box that supports the neck portion of the hearth roll has a seal lip that is slidably contacted with the neck portion in order to prevent dust from entering. A sealing device for sealing between the neck portion and the member is mounted.

  The inside of the continuous annealing furnace has an area of several hundred degrees or more. The hearth of the hearth roll passed into the furnace has cooling water or the like like a roll installed in the atmosphere of a rolling mill or continuous casting machine. Because it cannot be cooled externally, it becomes quite hot. For this reason, the neck part supported by the bearing box outside the furnace also becomes a high temperature of 150 ° C. or higher due to heat conduction from the body part. In addition, since the hearth roll is long as described above, the amount of thermal expansion in the axial direction also increases, and the neck portion not only slidably contacts the seal lip of the seal member in the rotational direction but also slidably contacts the axial direction.

  In order to improve the sealing performance, the sealing device for the bearing box that supports the roll neck of a large rolling mill or continuous casting machine has a ring-shaped seal lip formed from an elastic body such as rubber. A seal member that is pressed by a spring is often used (see, for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 8-4776 JP 2004-74289 A

  As described above, the hearth roll is greatly deflected, the neck portion thereof is heated to a high temperature of 150 ° C. or more, and is also in sliding contact with the seal lip of the seal member in the axial direction due to a large amount of thermal expansion in the axial direction. When a seal member that presses a seal lip as described in Patent Documents 1 and 2 with a ring-shaped spring from the back side is used for the box sealing device, the seal lip formed of an elastic body is bent by the hearth roll. On the side facing the displacement, there is a problem that the sliding contact portion with the neck portion of the seal lip is worn at an early stage, and the sliding contact portion with the neck portion of the seal lip is worn at an early stage and the sealing performance of the sealing device is lowered.

  In addition, the amount of thermal expansion of the hearth roll changes greatly at the start of operation of the continuous annealing furnace, and at the start of operation, the lubricating oil in the bearing box is sufficiently supplied to the sliding portion of the neck portion and the seal lip of the seal member. Therefore, there is a problem that the sliding resistance in the axial direction between the neck portion and the seal lip is increased due to the thermal expansion.

  Therefore, an object of the present invention is to provide a sealing device for a hearth roll bearing box that can maintain the hermeticity of the hearth roll bearing box for a long period of time and can smoothly allow thermal expansion of the hearth roll.

  In order to solve the above-described problems, the present invention is mounted on a bearing box in which a rolling bearing with a centering function for supporting a neck portion of a hearth roll of a continuous annealing furnace is installed, and the bearing box is attached to the hearth roll. In a sealing device for a hearth roll bearing box that is sealed by a seal member having a seal lip formed of an elastic body that is slidably contacted with the neck portion, the seal lip that is slidably contacted with the neck portion of the hearth roll is a ring from the back side. A configuration in which the sliding contact portion with the neck portion of the seal lip is formed of a tetrafluoroethylene resin is employed.

  That is, the seal lip that is slidably contacted with the neck portion of the hearth roll is pressed from the back side with a ring-shaped spring to improve the sealability of the bearing box, and the slidable contact portion with the neck portion of the seal lip is excellent. By forming it with tetrafluoroethylene resin that has high wear resistance and high heat resistance, the seal lip will not wear even if it is in sliding contact with the neck at a high temperature with a large contact pressure, and the sealability of the bearing housing will be maintained for a long period of time. I was able to do it.

  Further, when the ethylene tetrafluoride resin is slidably contacted with the neck portion at the sliding contact portion of the seal lip, a very small amount is peeled off to coat the surface of the neck portion, and the sliding resistance is remarkably reduced. Therefore, the sliding contact resistance between the neck portion and the seal lip in the axial direction due to the thermal expansion of the hearth roll can be reduced, and the thermal expansion of the hearth roll can be allowed smoothly.

  By making the rolling bearing with the aligning function a cylindrical roller bearing with an aligning ring, the length of the rolling bearing with the aligning function is made compact and the distance from the bearing center to the mounting position of the seal member is shortened. In addition, the deflection displacement at the sliding contact portion with the neck portion of the seal lip can be reduced.

  The sealing device for the hearth roll bearing box according to the present invention improves the sealability of the bearing box by pressing the seal lip slidably contacted with the neck portion of the hearth roll with a ring-shaped spring from the back side. The sliding contact part is made of tetrafluoroethylene resin so that the seal lip does not wear even if it comes into sliding contact with the high temperature neck part with a large contact pressure, so that the sealability of the bearing box is maintained for a long time. be able to. Further, the sliding contact resistance between the neck portion and the seal lip in the axial direction due to the thermal expansion of the hearth roll can be reduced, and the thermal expansion of the hearth roll can be allowed smoothly.

  By making the rolling bearing with the aligning function a cylindrical roller bearing with an aligning ring, the length of the rolling bearing with the aligning function is made compact and the distance from the bearing center to the mounting position of the seal member is shortened. In addition, the deflection displacement at the sliding contact portion with the neck portion of the seal lip can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a bearing box 3 of a hearth roll 2 of a continuous annealing furnace 1 using a sealing device according to the present invention. As for the hearth roll 2, the trunk | drum 2a is handed over in the furnace, the neck part 2b is supported by the bearing box 3 outside the furnace, and in order to allow the large deflection of the hearth roll 2 to the bearing box 3, A cylindrical roller bearing 4 with a centering ring which is a rolling bearing with a centering function is incorporated, and two seal members 5 constituting a sealing device are mounted on the front lid 3a and one on the rear lid 3b of the bearing housing 3. ing.

  The cylindrical roller bearing 4 with the aligning ring is positioned by a spacer 6 in which an inner ring 4a is externally fitted to the neck portion 2b of the hearth roll 2 and is also fitted to the neck portion 2b. The outer ring 4b is supported by a double curved surface seat of an aligning ring 4c fitted inside the bearing housing 3, and a plurality of cylindrical rollers 4d are arranged between the inner ring 4a and the outer ring 4b.

  As shown in an enlarged view in FIG. 2, each seal member 5 mounted on the front lid 3a of the bearing box 3 has a ring-shaped spring 5b fitted on the back side of a seal lip 5a formed of rubber. The seal lip 5a is pressed by the spring 5b from the back side so as to be in sliding contact with the outer peripheral surface of the spacer 6 fitted on the neck portion 2b. The sliding contact portion is made of tetrafluoroethylene resin. A chip 5c is attached. Although the enlarged illustration is omitted, the seal member 5 mounted on the rear lid 3b of the bearing housing 3 has the same configuration, and the sliding of the seal lip 5a that is in sliding contact with the outer peripheral surface of the holding ring 7 fitted on the neck portion 2b. A chip 5c made of tetrafluoroethylene resin is attached to the contact portion.

  In the embodiment described above, two seal members constituting the bearing box sealing device are mounted on the front lid and one on the rear lid. However, the number of these seal members mounted is limited to that of the embodiment. Never happen.

  Further, the rolling bearing with the aligning function incorporated in the bearing housing is not limited to the cylindrical roller bearing with the aligning ring of the embodiment, and can be a self-aligning roller bearing or a self-aligning ball bearing. These are longer than the cylindrical roller bearings with aligning rings, and the distance from the center of the bearing to the mounting position of the seal member becomes longer, and the deflection displacement at the sliding contact portion of the seal lip increases. is there.

The longitudinal cross-sectional view which shows the bearing box of the hearth roll using the sealing device which concerns on this invention 1 is an enlarged longitudinal sectional view showing the main part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Continuous annealing furnace 2 Hearth roll 2a Body part 2b Neck part 3 Bearing box 3a Front cover 3b Rear cover 4 Cylindrical roller bearing 4a with an aligning ring Inner ring 4b Outer ring 4c Centering ring 4d Cylindrical roller 5 Seal member 5a Seal lip 5b Spring 5c Tip 6 Spacer 7 Holding ring

Claims (2)

  A rolling bearing with a centering function that supports the neck portion of the hearth roll of a continuous annealing furnace is mounted on a bearing box, and the bearing box is formed of an elastic body that is in sliding contact with the neck portion of the hearth roll. In a sealing device for a hearth roll bearing box that is sealed with a seal member having a seal lip, the seal lip slidably contacted with the neck portion of the hearth roll is pressed from the back side with a ring-shaped spring, and the neck of the seal lip A sealing device for a hearth roll bearing box, wherein the sliding contact portion with the portion is made of tetrafluoroethylene resin.   The sealing device for the hearth roll bearing box according to claim 1, wherein the rolling bearing with a centering function is a cylindrical roller bearing with a centering ring.

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