Roll bearing and application thereof

Abstract

The invention discloses a roll bearing (10) used in a rolling mill, the roll bearing (10) has an outer diameter of more than 400 mm, and comprises an inner ring (1) in clearance fit with a roll neck, an outer ring in clearance fit with a bearing seat, and at least one row of rolling bodies arranged between the inner ring and the outer ring. Wherein the inner ring (1) is provided with lubrication grooves (2, 6) for storing a lubricant in an inner hole (11), and the lubrication grooves (2, 6) are closed lubrication grooves (2, 6) which are not intersected with the axial end face (3) of the inner ring (1). On the basis of the roll bearing (10), the invention also provides a rolling mill which comprises a roll for rolling metal into a specified shape and the roll bearing (10) playing a rolling support role at the roll neck position.

Description

Technical Field

[0001] The present invention relates to a roll bearing used in a rolling (steel) mill and a rolling mill using the roll bearing. Background Art

[0002] In the metallurgical industry, a rolling (steel) mill generally includes a roll for rolling metal into a specified shape and a roll bearing at the neck of the roll (hereinafter referred to as the "roll neck") that plays a rolling support role. Since the roll is subjected to huge loads and / or extremely high temperatures during operation, the roll bearings located at the roll neck often need to be maintained and replaced. In order to facilitate assembly and disassembly, a clearance fit is usually used between the bearing and the roll neck. This is because, especially under heavy loads, the creep of the inner ring of the bearing on the roll neck will cause the roll neck surface, which has a much lower hardness than the bearing steel, to be worn. In addition, in order to prevent wear and burning, the inner ring of the bearing and the roll neck need to be lubricated.

[0003] Figure 1 The application scheme of the bearing inner ring in the traditional case is shown as a spiral lubrication groove (hereinafter referred to as "spiral groove") formed in the inner hole. The spiral groove runs through the two end faces of the inner ring in the axial direction to form a so-called "open" structure, which is used to transport and / or maintain the lubricant on the mating surface between the inner ring and the roll neck. In addition, the spiral groove filled with lubricant also has the function of absorbing wear particles. However, the spiral groove of the open structure will intersect with the end face of the inner ring to form an end face protrusion P, such as Figure 1 The protrusions are likely to scratch the surface of the roll neck that is misaligned and inserted into the inner ring during the assembly and disassembly of the bearing (as mentioned above, because the hardness of the bearing steel is much higher than that of the roll neck), which is absolutely not allowed in equipment maintenance.

[0004] In order to solve the above technical problems, the existing solution is to open an axial guide groove 4 in a certain range adjacent to the inner ring end face in the inner hole of the inner ring, such as Figure 2 The guide groove is generally annular and has an inner diameter larger than the rest of the inner hole, thereby forming a radial gap with the roll neck, in order to avoid the threat posed by the aforementioned end face protrusion P to the roll neck surface. However, the spiral groove and the guide groove still meet in the inner hole of the inner ring to form a protrusion (hereinafter referred to as "inner hole protrusion") P, as shown in FIG. Figure 2 As shown. Although the inner hole spike P is axially located in the inner hole of the inner ring (formed at the bottom of the guide groove 4), it may still scratch the surface of the roll neck during the bearing assembly and disassembly process. Therefore, the existence of the spike caused by the lubrication groove has not been eradicated.

[0005] Reality calls for a roll bearing that can fundamentally prevent the spikes of the spiral groove from scratching the roll neck surface while not affecting the function of the lubrication groove. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a roller bearing used in a rolling mill. The bearing has an outer diameter of more than 400 mm, and comprises an inner ring that is clearance-matched with a roll neck, an outer ring that is clearance-matched with a bearing seat, and at least one row of rolling elements arranged between the inner ring and the outer ring. The inner ring has a lubrication groove for storing lubricant formed in its inner hole, and the lubrication groove is a closed lubrication groove that does not intersect with the axial end face of the inner ring.

[0007] In the above-mentioned roller bearing, the closed lubrication groove does not intersect with the inner ring end face to form a spike, thus fundamentally avoiding the risk of the spike formed by the lubrication groove scratching the roller neck surface. In addition, since a minimum spacing is formed between the lubrication groove and the inner ring end face, even if the roller neck is misaligned to a certain extent during the assembly process of the inner ring, the lubrication groove located "behind" the minimum spacing will not become an obstacle to the roller neck entering the inner ring. Taking the roughly annular spiral groove as an example, the existence of the minimum spacing can, to a certain extent, avoid the inconvenience caused by the spiral groove being too close to the inner ring end face to the bearing assembly.

[0008] Based on the above-mentioned roll bearing, the present invention also provides a rolling mill, comprising a roll for rolling metal into a specified shape and the above-mentioned roll bearing for performing rolling support at the roll neck position.

[0009] The above-mentioned rolling mill no longer has the risk of damaging the roll neck during the maintenance and replacement of the roll bearings, which is very helpful in reducing the maintenance cost of the equipment and improving the maintenance efficiency of the workers.

[0010] Various embodiments and beneficial technical effects of the present invention are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram showing the structure of a conventional bearing inner ring where a spiral groove intersects with the inner ring end face to form an end face protrusion;

[0012] Figure 2 A schematic cross-sectional view showing the intersection of the spiral groove and the guide groove to form an inner hole cusp in the presence of the guide groove;

[0013] Figure 3 A schematic diagram showing the distribution of the closed lubrication grooves in the inner ring of the bearing according to the present invention; and

[0014] Figure 4 A cross-sectional view of the groove body of the closed lubrication groove of the present invention is shown. DETAILED DESCRIPTION

[0015] In the following description, the same or similar reference numerals are always used to indicate the same or similar components. In addition, the terms indicating directions, such as "axial", "radial" and "circumferential direction", refer to the axial, radial and circumferential directions of the components being described unless otherwise limited or specified.

[0016] Figure 3 The schematic diagram of the distribution of the closed lubrication grooves used in the present invention in the inner ring of the bearing is shown. The figure takes a four-row tapered roller bearing 10 formed by two double-row tapered roller bearings in parallel as an example, showing that the inner ring 1 has a spiral lubrication groove (referred to as "spiral groove") 2 for conveying and / or storing lubricant formed in its inner hole 11. The spiral groove 2 is formed with a start and end position 2a and 2b at a position close to the inner ring end face 3 in the axial direction, and extends continuously along the inner surface of the inner hole 11 between the start and end positions 2a and 2b. The minimum spacing δ with a value not equal to zero is formed between the start and end positions 2a and 2b and the inner ring end faces 3 on both sides, and the existence of the minimum spacing δ prevents the spiral groove 2 from intersecting with the inner ring end face 3 on either side. In addition, unlike the traditional inner ring structure, the inner ring 1 has no guide groove 4 formed in its inner hole 11, so there is no possibility that the spiral groove 2 will form an inner hole protrusion P due to the intersection with the guide groove 4.

[0017] In the above embodiments, the spiral groove is used as a specific example of a lubrication groove, which shows that any form of closed lubrication groove is located within the end face of the inner ring in the axial direction, and therefore will not intersect with the end face of the inner ring to form a spike, thereby fundamentally eliminating the possibility of the inner ring spike scratching the roll neck.

[0018] In addition, the existence of the minimum spacing δ also means that the inner hole 11 of the inner ring forms a "blank area" on the axial inner side of its end face 3. When the roll neck is inserted into the inner hole, there is no lubrication groove structure in the blank area except the smooth inner wall of the inner hole that may prevent the roll neck from entering the inner hole, thus bringing smoothness and convenience to the inner ring assembly that is different from the past. However, if the blank area is too large, it means that the lubrication area between the inner ring and the roll neck is reduced. In view of this, the minimum spacing δ should have an optimal size range. Analysis shows that the minimum spacing δ is preferably between 5 and 20 mm, and more preferably between 5 and 10 mm.

[0019] from Figure 3 It can also be seen that the depth of the spiral groove 2 at the start and end positions 2a and 2b gradually transitions from zero to the predetermined groove depth. This slope design allows the tool to gradually feed from zero to the predetermined groove depth during the cutting process, and then gradually return from the predetermined groove depth to zero. The slope design conforms to the actual cutting process and avoids the inconvenience caused by the abrupt change of the groove depth and the stress concentration caused by it.

[0020] As an important technical feature, the improved spiral groove 2 of the present invention has a smaller pitch than the conventional spiral groove. Figure 3 As shown, the pitch B of the spiral groove 2 used in the present invention is generally between 19 and 39 mm. In a preferred case, the pitch B is further between 32 and 38 mm. It is not difficult to understand that the shortened pitch increases the distribution density of the spiral groove in the inner hole, which helps to enhance the lubrication between the inner ring and the roll neck.

[0021] To further improve lubrication, the inner ring 1 may further be provided with an axially extending linear lubrication groove (referred to as a "linear groove") 6 in its inner hole 11, such as Figure 3 As shown. Similar to the case of the spiral groove 2, the linear groove 6 also has start and end positions 6a, 6b in the inner hole 11, and a minimum spacing σ is formed between the start and end positions 6a, 6b and the nearest inner ring end face 3. Similar to the case of the spiral groove 2, the minimum spacing σ prevents the linear groove 6 from intersecting with the inner ring end face 3 to form a sharp protrusion.

[0022] As a preferred embodiment, the linear grooves 6 can be formed in the inner hole 11 of the inner ring 1 at regular circumferential intervals and intersect with the spiral grooves 2, thereby forming a staggered grid-like distribution of lubricating grooves in the inner hole 11. In one case, the circumferential interval of the linear grooves 6 can be significantly larger or smaller than the pitch B of the spiral grooves 2, thereby constructing a roughly rectangular grid distribution of lubricating grooves in the inner hole 11; or, in another case, the circumferential interval of the linear grooves 6 can be substantially consistent with the pitch B of the spiral grooves 2, thereby constructing a roughly square grid distribution of lubricating grooves in the inner hole 11. The above-mentioned equilateral or unequal rectangular grid distribution ensures that the lubricant is fully covered between the inner ring and the roll neck, which is an important feature that distinguishes the present invention from the lubricating grooves.

[0023] Figure 4 The cross-sectional view of the closed lubrication groove used in the present invention is shown. As can be seen from the figure, both the spiral groove 2 and the linear groove 6 have a roughly trapezoidal groove opening with an arc-shaped side wall. This shape of groove opening can be expanded by the tool reciprocating cutting on the same path, which is not only simple to operate, but also avoids the risk of excessive one-time cutting that may cause the tool to become blocked. In addition, compared Figure 2 and Figure 3 It can also be seen that the width of the lubrication groove of the present invention is greater than that of the conventional lubrication groove. On the one hand, a wide groove can accommodate more lubricant, thereby achieving more adequate lubrication. On the other hand, widening the groove will weaken the support structure of the inner ring, thereby reducing the bearing capacity of the bearing. In view of this, the appropriate width of the groove is ultimately determined to be 1.5 to 5.5 times its depth. In a further preferred case, the width of the notch is determined to be 2.5 to 4.5 times its depth.

[0024] Taking the four-row tapered roller bearing 10 as an example, the technical solution of forming a closed spiral groove 2 and a closed linear groove 6 in the inner hole 11 of the inner ring 1 is described above. Depending on the needs of the application, other types of rolling bearings, such as cylindrical roller bearings and spherical roller bearings, can also adopt the above technical solution of the present invention in the case of single-row, double-row or four-row distribution. The rolling bearing with a closed lubrication groove is particularly suitable for replacing the rolling bearing with an open lubrication groove in the existing rolling mill. It can not only effectively prevent the sharp protrusion of the open lubrication groove in the inner ring from scratching the surface of the roll neck, but also does not affect the lubrication of the mating surface between the inner ring and the roll neck.

[0025] It is necessary to point out that the object of the present invention is large and extra-large roller bearings with an outer diameter of more than 400 mm (up to 2200 mm), in which the design of the lubrication groove not only needs to fully cover the entire mating surface of the inner ring of the bearing, but also needs to meet the technical requirements of the inner ring in many aspects such as load bearing and structural deformation. In short, the improvement of the lubrication groove in the present invention is not a simple change in shape and size, but a substantial improvement involving many factors such as bearing morphology, load-bearing capacity and high temperature tolerance made by the inventor based on the long-term maintenance experience and lessons of the rolling mill. This improvement is substantially different from the conventional lubrication of small bearings, such as the lubrication of the bearing surface of the sliding bearing, in terms of application meaning.

[0026] Those skilled in the art should understand that the above-mentioned roller bearing and its application are not limited by the specific implementation methods, and the more general technical solutions shall be subject to the limitations in the attached claims. Any changes and improvements to the present invention, as long as they comply with the limitations in the attached claims, shall fall within the protection scope of the present invention.

Claims

1. A roller bearing (10) for use in a rolling mill, having an outer diameter of more than 400 mm, comprising an inner ring (1) having a clearance fit with a roll neck, an outer ring having a clearance fit with a bearing seat, and at least one row of rolling elements arranged between the inner ring and the outer ring, wherein: The inner ring (1) has a lubrication groove (2, 6) for storing lubricant formed in its inner hole (11), characterized in that the lubrication groove (2, 6) is a closed lubrication groove (2, 6) that does not intersect with the axial end face (3) of the inner ring (1).

2. The roller bearing (10) according to claim 1, characterized in that: The lubricating grooves (2, 6) include spiral grooves (2) and / or linear grooves (6), which form a minimum spacing (δ, σ) with a non-zero value between their axial starting and ending positions (2a, 2b, 6a, 6b) and the nearest inner ring end face (3).

3. The roller bearing (10) according to claim 2, characterized in that: The minimum spacing (δ, σ) is between 5 and 20 mm.

4. The roller bearing (10) according to claim 2, characterized in that: The spiral groove (2) has an axial pitch of 19 to 39 mm.

5. The roller bearing (10) according to claim 2, characterized in that: The depth of the lubricating groove (2, 6) at the starting and ending positions (2a, 2b, 6a, 6b) gradually transitions from zero to a predetermined groove depth.

6. The roller bearing (10) according to claim 2, characterized in that: The lubrication grooves (2, 6) include spiral grooves (2) and linear grooves (6), wherein the linear grooves (6) are regularly spaced in the circumferential direction of the inner hole (11) and together with the spiral grooves (2) form a grid-like distribution of lubrication grooves in the inner hole (11).

7. The roller bearing (10) according to any one of claims 1 to 6, characterized in that: The lubrication grooves (2, 6) have substantially trapezoidal groove openings with arc-shaped side walls.

8. The roller bearing (10) according to claim 7, characterized in that: The width of the trapezoidal notch is 1.5 to 5.5 times its depth.

9. The roller bearing (10) according to any one of claims 1 to 6, characterized in that: The roller bearing (10) is a tapered roller bearing, a cylindrical roller bearing or a spherical roller bearing, and is arranged in a single row, double row or four rows.

10. A rolling mill comprising a roll for rolling a metal into a specified shape and a roll bearing (10) as claimed in any one of claims 1 to 9 which plays a rolling support role at the roll neck position.

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