Device for sealing roll bearings

Abstract

The present invention relates to a device for sealing a roll bearing to contaminated cooling water, which flows down the end surfaces of the roll 1 throughout the operation of the roll 1. In particular, a gap 15 for lubrication between a roll neck sleeve positioned on the roll neck of the roll and a bearing sleeve 6 of the bearing housing 5, which is coaxially positioned with respect to the roll neck sleeve and in which the roll 1 is rotatably supported, is sealed. The device according to the present invention for sealing is configured to consist of a plurality of components; in particular, there is a gap 15 between an annular extension 7 as part of the sealing material and a second leg 13 of an L-shaped annular molded body 11. The annular extension 7 is provided with an outlet groove 9 at its periphery for the discharge of cooling water flowing out from the roll 1. In order to prevent the gap 15 and the area subsequently located in the gap 15 from being contaminated with contaminated cooling water, and to prevent the L-shaped annular molded body 11 located therefrom becoming non-functional due to this contamination, according to the present invention, it is intended that not only must the outflow groove 9 have a minimum height, but rather that the ratio of the height and width of the ring-shaped outflow groove to the diameter of the bottom of the outflow groove must also be within predetermined limits.

Description

Technical Field

[0001] The present invention relates to a roll bearing sealing device for sealing bearings for rolls for rolling, particularly for metal strips, against contaminated cooling water, which cooling water runs down also on the end side surfaces of the roll during operation of the roll. In particular, the gap for lubricant between a roll neck sleeve arranged on the roll neck of the roll and the bearing housing or the bearing sleeve of the bearing housing in which the roll is rotatably supported coaxially with respect to the roll neck sleeve is sealed.

Background Art

[0002] Roll bearing sealing devices of this type are basically known from the prior art, for example Patent Document 1. The roll bearing sealing device disclosed therein is shown in FIG. 3. This roll bearing sealing device is intended for the arrangement between the end side surface 10 of the roll 1 and a chuck 5, also referred to as a bearing housing, having an assigned bearing sleeve 6, in which chuck or bearing housing the roll 1 is rotatably supported by means of the roll neck 2 of this roll. This roll bearing sealing device is formed of a plurality of members. This roll bearing sealing device comprises a ring-shaped roll neck seal 4, which roll neck seal is arranged on the roll body side in front of the annular seal 8. This annular seal is firmly connected to the annular extension 7 of the bearing housing 5. The sealing lip 18 of the annular seal is placed in a sealing contact on the end side surface of the roll. A ring-shaped and L-shaped in cross section annular molded body 11 is firmly connected to the end side surface of the roll 1 by means of the first leg 12 of this L-shaped annular molded body. The sealing lip 18 of the annular seal abuts against this first leg. The ring-shaped second leg 13 of the L-shaped annular molded body surrounds the region of the annular seal 8 and the annular extension 7 further outward in the radial direction. The annular extension 7 has an outward-opening outflow groove 9 around its outer circumference, and this outflow groove is not covered, or at least partially covered, by the second leg 13 of the L-shaped annular molded body 11.

[0003] To that extent, Patent Document 1 discloses a broader concept than that of Claim 1.

[0004] In Patent Document 1, it is explained that the spacing, i.e., the height of the gap 15 between the annular extension 7 and the second leg 13 of the L-shaped annular molded body 11, is advantageous when it is between 0.5 mm and 1.5 mm. With this gap size, the offset that should be imparted by the roll in the operating state is still achievable. In addition, this keeps the gap (labyrinth) narrow enough that only the most restricted path possible into the area of ​​the sealed lip 18 is exposed to the use of potentially contaminated cooling water. This has a positive or advantageous effect, as it prevents the area from becoming contaminated so quickly and, consequently, allows it to function well for a longer period.

[0005] While this described configuration with narrowed gaps may indeed have the aforementioned effect if necessary, it does not address the underlying problem. This problem is that, throughout the rolling process, contaminated cooling water remains in the outlet groove up to the height of the gaps because the contaminated cooling water cannot be discharged in sufficient quantities. If this is indeed the case, the contaminated cooling water will be undesirably drawn into or sucked into the gap at the opening facing the outlet channel, thereby causing the aforementioned problems.

[0006] Regarding the suction of cooling water into the (annular) gap 15, the following physical effects are the cause: namely, 1. The flow state that occurs between the second leg of an L-shaped molded body and the annular sealing material or annular extension is referred to in the literature as Couette flow (Couette-Stroemung). A Couette flow is a flow within a narrow gap, driven by a moving wall. In the laminar flow case, a linear velocity profile occurs between the two walls that partition the gap. The gap geometry described in Patent Document 1 is formed by two cylinders, one of which is located inside the other, and in this process, the wall of one cylinder rotates. Here, a special case of Couette flow occurs, which is the so-called Taylor-Couette flow (Taylor-Couette-Stroemung). Due to centrifugal force (rotation), a so-called Taylor vortex (Taylor-Wirbel) is formed, and this Taylor vortex stands perpendicular to the axis of rotation. The resulting vortex topology (wirbtopologie) configures the transport of cooling water from one opening side of the gap to the other side, or in this case, into the region of the sealed lip 18. In some cases, contaminated cooling water is, so to speak, drawn in on one side and unfavorably transported through the gap to the sealant.

[0007] The lower limit on which Taylor vortices are formed can be indicated by the Reynolds number Re: namely,

number

number

number

number

[0008] Here, if known devices for roll sealing are considered, and the Reynolds number is determined by these boundary conditions, then in almost all cases, a Reynolds number is practically given that exceeds the limit according to the right-hand side of equation (2). This means that the Taylor vortex described above may be generated, and that the contaminated cooling water may be undesirably drawn through the gap into the region of the sealed lip 18.

[0009] 2. A second point of view, which in some cases leads to the same problem of contaminated water being transported through the gaps, lies in the geometric changes of the gap geometry when the gap geometry is observed along its periphery. The roll neck support shaft is never precisely concentric with the support roll shaft in operation, but rather is offset in the direction of the external load. Therefore, the gap formed between the second leg of the L-shaped molded body and the annular sealing material or annular extension is not distributed at the same height on the outer circumference. There is one outer perimeter region where the gap becomes narrower, and there is another outer perimeter region where the gap expands. In the expanded region, contaminated water may be drawn in and pushed out again into the region opposite the narrowed region. This behavior is similar to that of a sliding bearing. During extrusion, contaminated water may be pressed into the area of ​​the sealing material, and this area should not be contaminated according to the disclosure in Patent Document 1.

[0010] In some cases, in order to prevent contaminated water from generally coming near the gap between the second leg portion of the L-shaped annular molded body and the annular sealing material or the annular extension portion, Patent Document 1 recommends using the outflow groove portion 9 disclosed therein at the peripheral portion of the annular extension portion.

[0011] However, various studies have clarified that the outflow groove portion at the peripheral portion can exhibit the above-described function imposed on this outflow groove portion only when the outflow groove portion satisfies the specified dimensions.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0013] Therefore, the problem underlying the present invention is to make the outflow groove portion at the peripheral portion of the annular extension portion, especially at the inlet opening of the gap directed towards the outflow groove portion, the gap between the end side surface of the roll body and the annular sealing material, and the region subsequent to this gap, be contaminated with contaminated cooling water as much as possible. Set the dimensions so that contamination is prevented sufficiently.

Means for Solving the Problems

[0014] This problem is solved by the subject matter of claim 1. Accordingly, the minimum height Hmin of the outflow groove portion is Hmin = 1.55 mm, and in addition, the ratio of the height H to the width B of the outflow groove portion with respect to the diameter D of the bottom of the outflow groove portion is

Number

[0015] This claimed physical relationship is derived from theoretical research and practical experience. An outlet passage sized in such a way is considered optimal, and in particular, to be sufficiently large, in order to prevent the blockage of contaminated cooling water up to the height of the inlet opening of the gap, and consequently to effectively prevent the suction of cooling water into the gap based on both of the effects described above.

[0016] Three figures are attached to the specification. [Brief explanation of the drawing]

[0017] [Figure 1] This is an enlarged cross-sectional view of an outflow channel according to the present invention. [Figure 2] This is a diagram illustrating the specific lower and upper limits related to the requested ratio. [Figure 3] This is a diagram of a roll bearing sealing device according to conventional technology. [Modes for carrying out the invention]

[0018] The present invention will be described in detail below in relation to the above-mentioned figures in the form of embodiments. In all figures, the same technical elements are indicated by the same reference numerals.

[0019] The roll bearing sealing device according to the present invention is based on a roll bearing sealing device known from the prior art, as shown in Figure 3. For a description of Figure 3, please refer to the configuration described above for the prior art and Patent Document 1. Except for the differences and additions described below, the above description also applies to apparatus according to the present invention.

[0020] As already mentioned, the present invention relates to a particularly excellent configuration of the outflow channel 9, which is shown in Figure 1 in cross-section and in an enlarged view. In Figure 1, a ring-shaped annular extension 7 can be seen, and the outflow channel 9 is formed around the periphery of this annular extension. The bottom of the annular sealing material is spaced at a height of diameter D from the central axis of the annular extension 7, and when the annular extension 7 is mounted on the roll neck 2, this central axis also corresponds to the central axis of the roll neck 2. It can be seen that the left boundary wall of the outflow groove 9 is covered by the second leg 13 of the L-shaped annular molded body 11, in which case a gap 15 is formed between the two elements. Reference numeral 12 indicates the first leg of the L-shaped annular molded body 11, which is firmly attached to the end surface of the roll cylinder. The height H of the outflow groove more precisely indicates, for example, the distance between the bottom of the outflow groove 9 and the lower surface of the second leg 13. The minimum height Hmin is the minimum of this interval; that is, The equation H≧Hmin holds true. Reference numeral B indicates the width of the outflow channel 9.

[0021] The inventor's credit lies with recognizing that, in order for the roll bearing sealing device according to the present invention to perform its intended function, the ratio of the height H to the width B relative to the diameter D must be within a specified range, as well as the minimum height Hmin of the outflow groove.

[0022] If this ratio is excessively small, contaminated cooling water may accumulate in the gap 15 between the second leg 13 of the L-shaped molded body 11 and the annular sealing material 8, and may be drawn into the gap by both of the effects described above. The contaminants that are aspirated together induce unwanted clogging within the gap and impair the functionality of the sealing lip in the subsequently placed area.

[0023] If the ratio of width B and height H to diameter D is excessively large, the flow velocity of the cooling water channel within the outflow groove 9 becomes so low that scale residue or contaminant residue is not washed away from the rolling process. These residues then adhere ("backen") within the outlet channel 9 based on their reactivity (corrosion, etc.), and after a short operating time, induce clogging of the outlet channel, thus incurring additional outlet resistance; and the outlet channel may no longer fulfill its inherent role of providing a sufficiently large outlet area for the contaminated cooling water. In this case as well, contaminated cooling water may accumulate up to the height of the gap 15 between the second leg 13 of the L-shaped molded body 11 and the annular sealing material or annular extension 7, and, based on the effects of both described above, may be drawn into the gap 15 and supplied to the sealing system unfavorably.

[0024] Based on theoretical research and practical experience, A minimum height of Hmin = 1.55 mm must be given, and It was found that the ratio of height H to width B to diameter D must be within the following limits: namely,

number

[0025] Accordingly, the outflow channel 9 is considered optimal, that is, it is considered to be configured neither excessively small nor excessively large in line with the purpose of the aforementioned configuration.

[0026] Figure 2 specifically illustrates the numerical range, and within this range, the requested ratio should have a lower limit of 0.1 and an upper limit of 120, according to formula (1). [Explanation of Symbols]

[0027] 1 roll 2 Roll neck 3 Roll neck sleeves 4 Roll neck seal 5 Chock 6. Bearing sleeve 7. Annular extension 8. Annular sealing material 9 Outlet channel 10 end side 11 L-shaped annular molded body 12 First leg 13. Second leg 15 Gap 18. Sealing Lip B Width The diameter of the ring-shaped outflow groove at the bottom of the D-ring-shaped outflow groove. Hmin Minimum height; corresponding to the minimum height H H Height of the outflow channel

Claims

[Claim 1] A device for sealing a roll bearing, This roll bearing has a bearing housing (5), and within this bearing housing, the roll (1) is rotatably supported by the roll neck (2). This device has a roll neck seal (4); This device has an annular seal (8), which is positioned on the roll drum side in front of the roll neck seal (4), and which has a sealing lip (18); This device has an annular extension (7), which is positioned in front of the bearing housing (5) in the axial direction, and which is firmly coupled to an annular sealing material (8), and which has a periphery of the annular extension having an outwardly opening, circumferentially extending outflow groove (9); And, An annular molded body (11) with an L-shape in cross-section is provided, comprising a first leg portion (12) and a second leg portion (13). The annular molded body (11) is firmly bonded to the end surface (10) of the roll (1) by the first leg portion (12) of the annular molded body. The sealing lip (18) of the annular sealing material (8) is in contact with the side surface of the first leg portion (12) which is oriented away from the roll cylinder, in a sealed contact state; The second leg (13) of the L-shaped annular molded body (11) covers and surrounds the region between the annular extension (7) and the annular sealing material (8), forming a gap (15), and sealing toward the roll cylinder; In the above device, Regarding the minimum height Hmin of the outflow channel (9), Hmin = 1.55 mm; and the ratio of the height H and width B of the outflow channel (9) to the diameter D of the bottom of the ring-shaped outflow channel is [Math 1] Within the limits of, Here, the outflow coefficient K Ａ =0.00985mm ３ / mm ２ And all dimensions are in millimeters; and H ≥ Hmin, A device characterized by the following features.

Images