Roll unit for rolling mill

Abstract

This invention provides a roll unit for a rolling mill that suppresses water ingress into the bearing and offers high protection against water. [Solution] A roll unit for a rolling mill comprising a shaft member, a roll rotatably mounted on the outer diameter side of the shaft member, bearings disposed at the axially outer ends of the shaft member and the roll, and a sealing mechanism disposed axially outer of the bearing. The sealing mechanism comprises an inner diameter side cover fitted to the outer diameter surface of the shaft member, an outer diameter side cover fitted to the inner diameter surface of the roll, and a sealing member fitted to the outer circumference of the inner diameter side cover, closing the space between the outer diameter side cover and the inner diameter side cover. The inner diameter side cover has a cylindrical portion fitted to the outer diameter surface of the shaft member and a flange portion projecting outwards from the axially outer side of the cylindrical portion. A radial groove is provided on the axially inner surface of the flange portion, and a through hole is provided that communicates with the radial groove and penetrates the flange portion in the axial direction.

Description

Technical Field

[0001] The present invention relates to a roll unit for rolling mills that constitutes backup rolls and the like used in a tension leveler, which is a metal rolling mill. Background Art

[0002] In the final step of a rolling operation, stress is removed by passing a workpiece (such as a steel plate) through a straightening machine called a tension leveler, thereby ensuring the accuracy of the workpiece. As shown in Fig. 8, some tension levelers include a work roll unit 101 and a deflector roll unit 102 opposing the work roll unit 101.

[0003] As shown in Fig. 8, the work roll unit 101 comprises a work roll 103, an intermediate roll 104, and a backup roll 105, and a deflector roll 106 of the deflector roll unit 102 is arranged on the opposite side of the work roll unit 101 with a workpiece W (such as a steel plate) interposed therebetween.

[0004] That is, the tension leveler directly straightens the workpiece W with the work roll 103, and the work roll 103 is supported by the intermediate roll 104 and the backup roll 105. For this reason, the backup roll 105 ultimately supports all of the load.

[0005] The backup roll 105 and other rolls are continuously sprayed with cleaning liquid to cool the rolled metal plate W and remove dust and other contaminants adhering to the metal plate, so a sealing mechanism is required to prevent the cleaning liquid from penetrating into the bearing. As a backup roll unit provided with a sealing mechanism, the one disclosed in Patent Document 1 has been proposed.

[0006] The backup roll unit shown in Patent Document 1, as shown in Figure 9, comprises a shaft member 110, a roll 111 rotatably positioned on the outer diameter side of the shaft member 110, ball bearings 112 interposed on both axial sides between the shaft member 110 and the roll 111, and sealing mechanisms 113 provided on the axially outer side of each of the ball bearings 112.

[0007] The sealing mechanism 113 includes an outer diameter side cover 114 fitted to the inner circumferential end of the roll 111, an inner diameter side cover 115 fitted to the outer circumferential end of the shaft member 110, and a sealing member 116 fitted to the outer circumference of the inner diameter side cover 115 to close the gap between the outer diameter side cover 114 and the inner diameter side cover 115.

[0008] Furthermore, Patent Document 2 describes a roll bearing that includes a mechanism for draining water that has entered the sealing mechanism. The sealing mechanism in Patent Document 2 includes a thrust ring that is fitted to the outer peripheral end of the shaft member and closes the openings on both axial ends of the roll. This thrust ring is provided with a flange that protrudes outward, and a drainage passage is formed that penetrates the flange axially. If water enters the sealing mechanism, the water is drained to the outside through this drainage passage. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2019-155400 [Patent Document 2] Publication No. 5-20891 [Overview of the project] [Problems that the invention aims to solve]

[0010] The device described in Patent Document 1 lacks a water drainage mechanism if water enters the sealing mechanism, which means that water may enter the bearing. Patent Document 2 includes a water drainage mechanism (drainage passage) in the sealing mechanism, but precise positioning of the drainage passage is required during assembly. Furthermore, the drainage passage in Patent Document 2 connects the external and internal spaces of the sealing mechanism, and no member is placed in the internal space to block the opening of the drainage passage. Therefore, if water enters from the outside through the drainage passage, it is easy for water to enter the entire internal space of the sealing mechanism, which can lead to water entering the bearing and potentially reducing bearing function and bearing life.

[0011] Therefore, the present invention provides a roll unit for a rolling mill that suppresses water ingress into the bearing and provides high protection from water. [Means for solving the problem]

[0012] The roll unit for a rolling mill of the present invention comprises a shaft member, a roll rotatably mounted on the outer diameter side of the shaft member, a bearing disposed at the axially outer end of the shaft member and the roll, and a sealing mechanism disposed axially outer of the bearing, wherein the sealing mechanism comprises an inner diameter side cover fitted to the outer diameter surface of the shaft member, an outer diameter side cover fitted to the inner diameter surface of the roll, and a sealing member fitted to the outer circumference of the inner diameter side cover and closing the space between the outer diameter side cover and the inner diameter side cover, wherein the inner diameter side cover has a cylindrical portion fitted to the outer diameter surface of the shaft member and a flange portion projecting outwards from the axially outer side of the cylindrical portion, and a radial groove is provided on the axially inner surface of the flange portion, and a through hole is provided that communicates with the radial groove and penetrates the flange portion in the axial direction. Here, the roll unit for the rolling mill comprises a shaft member, a roll rotatably mounted on the outer diameter side of the shaft member, and a bearing positioned between the shaft member and the roll, on the axial side of the roll. The direction of the axial axis of the roll and the shaft member is called the "axial direction." The direction perpendicular to the "axial direction" is called the "radial direction." The "circumferential direction" refers to the direction along the circumference that makes one revolution around the axis of the central axis of the inner and outer rings. The definitions of these directions are the same in the following explanation.

[0013] The roll unit for a rolling mill of the present invention has a radial groove on the axial inner surface of the flange portion of the inner diameter side cover, and a through hole that communicates with the radial groove and penetrates the flange portion in the axial direction. The radial groove and the through hole serve as a water discharge mechanism for water that has entered from the outside. That is, the radial groove acts as a guide path for water that has entered the sealing mechanism, and can guide the water to the through hole within the sealing mechanism. Furthermore, the through hole acts as a water discharge path, and can discharge the water to the outside of the sealing mechanism through the through hole. As a result, the roll unit for a rolling mill of the present invention can enhance the water discharge function for water that has entered the sealing mechanism.

[0014] In the above configuration, the outer diameter side cover may have a cylindrical portion that fits onto the inner diameter surface of the roll and a flange portion that protrudes from the axially inner side of the cylindrical portion toward the inner diameter side, and a gap may be formed between the flange portion of the inner diameter side cover and the cylindrical portion of the outer diameter side cover. In this case, the gap can be formed when the axially inner surface of the flange portion of the inner diameter side cover and the axially outer end surface of the cylindrical portion of the outer diameter side cover face each other. Alternatively, the cylindrical portion of the outer diameter side cover may have a projection that protrudes axially on the outer diameter side at its axially outer end, and the gap may be a labyrinth gap formed when the projection is positioned toward the outer diameter side of the flange portion of the inner diameter side cover.

[0015] Thus, a sealing mechanism in which a gap is formed between the flange portion of the inner diameter cover and the cylindrical portion of the outer diameter cover can enhance the function of suppressing water ingress into the sealing mechanism, in addition to its water discharge function. In particular, if the gap is a labyrinth gap, the path for water ingress from the outside can be made more complex, further enhancing the function of suppressing water ingress.

[0016] In the above configuration, the axially inward opening of the through-hole may be provided at a position facing the sealing member. With this configuration, even if water attempts to enter the sealing mechanism from the outside through the through-hole, the sealing member can block the flow of water from the through-hole, thereby restricting the entry of water into the sealing mechanism. This further enhances the function of suppressing water intrusion.

[0017] A tension leveler comprises a work roll, an intermediate roll supporting the work roll, and a backup roll supporting the intermediate roll. The backup roll supports all loads, and the roll unit for rolling mills of the present invention is particularly effective when used as the backup roll of the tension leveler. [Effects of the Invention]

[0018] This invention enhances the water discharge function that has entered the sealing mechanism, thereby suppressing water ingress into the bearing and providing a high level of protection from water. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0019] [Figure 1] FIG. 1 is a cross-sectional view of a roll unit for a rolling mill according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a sealing mechanism constituting the roll unit for a rolling mill of FIG. 1. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a main part of the sealing mechanism of FIG. 2. [Figure 4] FIG. 4 is an enlarged cross-sectional view taken along line A-A of FIG. 3. [Figure 5] FIG. 5 is an enlarged cross-sectional view taken along line B-B of FIG. 3. [Figure 6] FIG. 6 is a cross-sectional view of a sealing mechanism constituting a roll unit for a rolling mill according to a second embodiment of the present invention. [Figure 7] FIG. 7 is an enlarged cross-sectional view of a main part of the sealing mechanism of FIG. 6. [Figure 8] FIG. 8 is a simplified diagram of a general tension leveler. [Figure 9] FIG. 9 is a partial cross-sectional view showing a conventional backup roll. [DESCRIPTION OF EMBODIMENTS]

[0020] Hereinafter, a roll unit for a rolling mill according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. The roll unit for a rolling mill of the present embodiment is used as a backup roll of a tension leveler, and as shown in FIG. 1, comprises: a shaft member; a roll; a double-row ball bearing as a thrust load bearing disposed axially outward of the roll between the shaft member and the roll; and a sealing mechanism disposed axially outward of the ball bearing and closing an annular space formed between the shaft member and the roll.

[0021] The shaft member 1 is a stepped shaft body, having a shaft body portion 1a formed in the axial middle portion, shaft ends 1b formed at both axial ends, and an intermediate portion 1c formed between the shaft body portion 1a and the shaft ends 1b. The shaft body portion 1a has an overall length shorter than the overall length of the roll 2 and is inserted into the roll 2 with a radial gap. The intermediate portions 1c are formed coaxially with the shaft body portion 1a on both axial outer sides of the shaft body portion 1a via steps. The intermediate portions 1c have an axial width dimension that is approximately the same as the bearing width of the ball bearing 3 and have a smaller outer diameter dimension than the shaft body portion 1a. The shaft ends 1b are formed coaxially with the shaft body portion 1a, axially outward from the intermediate portion 1c. A circumferential groove 10 is formed on the outer surface of the shaft ends 1b, and a retaining ring 5 is fitted into the circumferential groove 10. The shaft ends 1b have a slightly smaller outer diameter dimension than the intermediate portion 1c.

[0022] Roll 2 is rotatably mounted on the outer diameter side of shaft member 1. Roll 2 is cylindrical and has a small diameter portion 2a on the axial inner side, a first fitting portion 2b which is axially outer than the small diameter portion 2a and has a larger inner diameter than the small diameter portion 2a, and a second fitting portion 2c which is axially outer than the first fitting portion 2b and has a larger inner diameter than the first fitting portion 2b. The first fitting portion 2b has an axial width dimension that is larger than the bearing width of the ball bearing 3. The second fitting portion 2c has an axial width dimension that is smaller than the axial width of the sealing mechanism 4.

[0023] The ball bearings 3 (3a, 3b) are double-row and comprise inner rings 5a, 5b, outer rings 6a, 6b, a plurality of balls 7a, 7b interposed between the inner rings 5a, 5b and the outer rings 6a, 6b, and cages 8a, 8b that hold the balls 7a, 7b. The outer rings 6a, 6b are press-fitted and fixed to the inner circumference of the first fitting portion 2b of the roll 2, and the inner rings 5a, 5b are fitted to the outer circumference of the intermediate portion 1c of the shaft member 1. The axial inner surface of the outer ring 6a of the axially inner ball bearing 3a abuts against the stepped portion between the small diameter portion 2a of the roll 2 and the first fitting portion 2b. Also, the axial inner surface of the inner ring 5a of the axially inner ball bearing 3a abuts against the stepped portion between the shaft body portion 1a and the intermediate portion 1c of the shaft member 1. The ball bearing 3 can be a deep groove ball bearing, an angular contact ball bearing, or a four-point contact ball bearing, and can be a thrust load bearing, that is, a bearing that can withstand a load in the thrust direction.

[0024] The sealing mechanism 4 comprises an inner diameter side cover 11 that fits onto the outer diameter surface of the shaft end 1b of the shaft member 1, an outer diameter side cover 12 that fits onto the inner diameter surface of the second fitting portion 2c of the roll 2, and a sealing member 13 that fits onto the outer circumference of the inner diameter side cover 11.

[0025] As shown in Figure 2, the inner diameter cover 11 has a cylindrical portion 11a that fits onto the outer diameter surface of the shaft end 1b of the shaft member 1, and a flange portion 11b that protrudes outward from the axially outer side of the cylindrical portion 11a. As shown in Figure 1, the inner diameter cover 11 has an axially inner end face of the cylindrical portion 11a that abuts against the inner ring 5b of the axially outer ball bearing 3b, and the axially outer movement of the cylindrical portion 11a is restricted by the retaining ring 5 at the axially outer end face of the cylindrical portion 11a.

[0026] A sealing member 13 is fitted to the outer surface of the cylindrical portion 11a. Furthermore, the cylindrical portion 11a is sealed between the outer surface of the shaft end 1b of the shaft member 1 by an O-ring 15 (see Figure 1) fitted into a circumferential groove 14 (see Figure 2) formed on its inner diameter surface.

[0027] As shown in Figure 1, the flange portion 11b is located axially outward from the axially outward end face of the roll 2. As shown in Figure 3, a radial groove 16 is provided on the axially inward surface 20 of the flange portion 11b. In this embodiment, there is one radial groove 16. As shown in Figures 3 and 4, this radial groove 16 extends from the inner diameter end to the outer diameter end of the flange portion 11b. In this embodiment, the radial groove 16 is formed from both a planar and curved surface, and has an arc shape in plan view, as shown in Figure 5.

[0028] Furthermore, as shown in Figures 3, 4, and 5, the flange portion 11b is provided with a through hole 17 that communicates with the radial groove 16 and penetrates the flange portion 11b in the axial direction. In this embodiment, the through hole 17 has a circular side surface as shown in Figure 4, and as shown in Figures 3 and 5, it has a straight hole shape with a uniform inner diameter and cross-sectional shape in the axial direction. As shown in Figure 3, the direction in which the through hole 17 extends is approximately parallel to the axis of the shaft member 1 in this embodiment. The radial groove 16 and the through hole 17 constitute a water discharge mechanism, which will be described later.

[0029] As shown in Figure 2, the outer diameter cover 12 has a cylindrical portion 12a that fits onto the inner diameter surface of the second fitting portion 2c of the roll 2, and a flange portion 12b that protrudes from the axially inner side of the cylindrical portion 12a toward the inner diameter side. As shown in Figure 1, the flange portion 12b extends radially at the boundary position between the first fitting portion 2b and the second fitting portion 2c of the roll 2, and the inner diameter side tip of the flange portion 12b faces the cylindrical portion 11a of the inner diameter cover 11 with a small gap between them. The outer diameter cover 12 is sealed between itself and the inner diameter surface of the second fitting portion 2c of the roll 2 by an O-ring 19 (see Figure 1) fitted into a circumferential groove 18 (see Figure 2).

[0030] As shown in Figure 3, the outer diameter side tip of the flange 11b of the inner diameter cover 11 reaches the radial center of the cylindrical portion 12a of the outer diameter cover 12. As a result, the axial inner surface 20 of the flange 11b of the inner diameter cover 11 and the axial outer end surface 21 of the cylindrical portion 12a of the outer diameter cover 12 face each other, forming a gap 22.

[0031] The seal 13 is formed from an annular elastic body and, as shown in Figure 2, has a seal body 13a that fits onto the outer circumference of the cylindrical portion 11a of the inner diameter side cover 11, and a lip 13b located axially inward of the seal body 13a. The axially outer portion of the seal body 13a abuts against the flange portion 11b of the inner diameter side cover 11. The lip 13b is formed to extend radially outward from the inner circumference of the axially inward portion of the seal body 13a toward the axially inward side. The axially inner edge of the lip 13b slides against the flange portion 12b of the outer diameter side cover 12 with an axial overlap.

[0032] As shown in Figure 3, the axially inner opening 23 of the through hole 17 (i.e., the opening on the inside of the sealing mechanism) is located facing the sealing member 13. That is, the opening 23 is located on the inner diameter side of the outer diameter surface 24 of the seal body 13a.

[0033] The radial groove 16 and through hole 17 described above serve as a water discharge mechanism for water that has entered from the outside. Specifically, as shown by arrow C in Figure 3, the radial groove 16 acts as a guide path for water that has entered the sealing mechanism, guiding the water to the through hole 17 within the sealing mechanism. Furthermore, as shown by arrow D in Figure 3, the through hole 17 acts as a water discharge path, allowing water to be discharged to the outside of the sealing mechanism through the through hole 17. In this way, the roll unit for the rolling mill of this embodiment can enhance the water discharge function for water that has entered the sealing mechanism, thereby suppressing water intrusion into the bearing and providing a high level of protection from water.

[0034] Furthermore, the axial inner surface 20 of the flange portion 11b of the inner diameter side cover 11 and the axial outer end surface 21 of the cylindrical portion 12a of the outer diameter side cover 12 face each other, forming a gap 22. A sealing mechanism 4 with this configuration can enhance the function of suppressing water ingress into the sealing mechanism (arrow C) in addition to the water discharge function.

[0035] By positioning the axially inner opening 23 of the through-hole 17 facing the sealing member 13, even if water attempts to enter the sealing mechanism from the outside through the through-hole 17, the sealing member 13 can block the flow of water from the through-hole 17, thereby restricting the entry of water into the sealing mechanism. This further enhances the water intrusion suppression function.

[0036] Figure 6 shows the sealing mechanism 30 of the roll unit for a rolling mill according to the second embodiment. The sealing mechanism 30 of the second embodiment includes an inner diameter side cover 11 and a sealing member 13, similar to the sealing mechanism 4 of the first embodiment shown in Figure 2, but the outer diameter side cover 31 differs from the outer diameter side cover 12 of the first embodiment (see Figure 2). As shown in Figure 6, the outer diameter side cover 31 in the second embodiment has a cylindrical portion 31a that fits onto the inner diameter surface of the second fitting portion 2c of the roll 2, and a flange portion 31b that protrudes from the axially inner side of the cylindrical portion 31a toward the inner diameter side. The flange portion 31b extends radially at the boundary position between the first fitting portion 2b and the second fitting portion 2c of the roll 2, and the inner diameter side tip of the flange portion 31b faces the cylindrical portion 11a of the inner diameter side cover 11 with a small gap between them. The outer diameter cover 31 is sealed between itself and the inner diameter surface of the second fitting portion 2c of the roll 2 by an O-ring 19 (see Figure 1) fitted into the circumferential groove 32.

[0037] The cylindrical portion 31a of the outer diameter cover 31 has a projection 33 that protrudes axially on the outer diameter side at its axially outer end. This projection 33 is positioned on the outer diameter side of the tip (outer diameter end) of the flange portion 11b of the inner diameter cover 11. As a result, a gap 34 is formed between the tip (outer diameter end) of the flange portion 11b of the inner diameter cover 11 and the axially outer end of the cylindrical portion 31a of the outer diameter cover 31. In this case, the gap 34 is a labyrinth gap consisting of a radial gap and an axial gap, as shown in Figure 7.

[0038] With the above configuration, the roll unit for the rolling mill of the second embodiment also provides the same effects as the roll unit for the rolling mill of the first embodiment. In particular, in the roll unit for the rolling mill of the second embodiment, the gap 34 is a labyrinth gap, so as shown by arrow C in Figure 7, the path for water to enter from the outside can be made complex, and the function of suppressing water intrusion can be further enhanced. Note that in the sealing mechanism of the roll unit for the rolling mill shown in Figures 6 and 7, components that are the same as those in the sealing mechanism of the roll unit for the rolling mill of the first embodiment are denoted by the same reference numerals as in Figures 2 and 3, etc., and their explanation is omitted.

[0039] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. In the embodiments, the backup roll was a so-called ball type in which only ball bearings are fitted at two locations along the axial direction of the shaft, thereby supporting the roll so as to be rotatable with respect to the shaft. However, a so-called needle type may also be used. In a needle-type backup roll, needle bearings are fitted at two locations along the axial direction of the shaft, and ball bearings are fitted on both sides (outside) of these axial bearings, thereby supporting the roll so as to be rotatable with respect to the shaft. For applications with large radial loads, the needle type is preferable, while for applications with small radial loads and where low torque is required, the ball type is preferable. The magnitude of the radial load and the required torque vary depending on the type of metal plate material and the usage conditions, and the present invention can be applied to either type. In the case of the ball type, the bearings do not have to be in double rows and may be in a single row as shown in Figure 9. Furthermore, while the present invention is particularly preferable for use as a backup roll, it can also be used for intermediate rolls and the like in similar environments.

[0040] Multiple radial grooves and through holes may be provided. In this case, the spacing between them in the circumferential direction can be set arbitrarily, and if three or more are provided, the spacing may be equal or unequal. The radial groove does not need to have a uniform circumferential or axial width from the inner diameter side to the outer diameter side; for example, it may gradually widen or narrow in the circumferential or axial width from the inner diameter side to the outer diameter side. The plan view shape of the radial groove is not limited to a curved shape and can be various shapes. The direction in which the radial groove extends does not necessarily have to be radial; it may be inclined with respect to the radial direction. In short, as long as the radial groove is continuous from the outer diameter end of the flange portion of the inner diameter cover to the through hole, its shape and direction of extension can be set in various ways. The through hole does not have to be circular on the side and can be various shapes. The inner diameter of the through hole does not have to be uniform in the axial direction; it may gradually increase in diameter from the inner side to the outer side in the axial direction. The direction in which the through-hole extends may be inclined with respect to the axis of the shaft member. In short, as long as the through-hole penetrates the flange portion of the inner diameter cover, its shape and direction of extension can be set in various ways. [Explanation of symbols]

[0041] 1 Shaft member 2 rolls 3 Bearings 4 Sealing mechanism 11 Inner diameter side cover 11a Cylindrical section 11b Tsubabe 12, 31 Inner diameter side cover 12a, 31a Cylindrical section 12b, 31b Tsuba 13. Sealing member 16 radial grooves 17 Through hole 20 Axial inner surface of the flange portion of the inner diameter side cover 21 Axial outer end surface of the cylindrical portion of the outer diameter side cover 22, 34 gaps 23 Opening 33 Protrusion

Claims

1. A roll unit for a rolling mill comprising a shaft member, a roll rotatably mounted on the outer diameter side of the shaft member, bearings disposed at the axially outer ends of the shaft member and the roll, and a sealing mechanism disposed axially outer of the bearing, The sealing mechanism comprises an inner diameter side cover that fits onto the outer diameter surface of the shaft member, an outer diameter side cover that fits onto the inner diameter surface of the roll, and a sealing member that fits onto the outer circumference of the inner diameter side cover and closes the space between the outer diameter side cover and the inner diameter side cover. The inner diameter side cover has a cylindrical portion that fits onto the outer diameter surface of the shaft member, and a flange portion that protrudes from the axially outer side of the cylindrical portion toward the outer diameter side. A roll unit for a rolling mill, characterized in that a radial groove is provided on the axial inner surface of the flange portion, and a through hole is provided that communicates with the radial groove and penetrates the flange portion in the axial direction.

2. The rolling mill roll unit according to claim 1, characterized in that the outer diameter side cover has a cylindrical portion that fits onto the inner diameter surface of the roll and a flange portion that protrudes from the axially inner side of the cylindrical portion toward the inner diameter side, and a gap is formed between the flange portion of the inner diameter side cover and the cylindrical portion of the outer diameter side cover.

3. The rolling mill roll unit according to claim 2, characterized in that the gap is formed so that the axial inner surface of the flange portion of the inner diameter side cover and the axial outer end surface of the cylindrical portion of the outer diameter side cover face each other.

4. The roll unit for a rolling mill according to claim 2, characterized in that the cylindrical portion of the outer diameter cover has a projection that protrudes axially on the outer diameter side at its axially outer end, and the gap is a labyrinth gap formed by the projection being positioned on the outer diameter side of the flange portion of the inner diameter cover.

5. The roll unit for a rolling mill according to claim 1, characterized in that the axially inner opening of the through hole is provided at a position facing the sealing member.

6. The rolling mill roll unit according to claim 1, characterized in that it is used as a backup roll for a tension leveler.

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