JP6512264B2 - Cylindrical roller bearing - Google Patents

Description

  The present invention relates to cylindrical roller bearings.

  In steelmaking plants, continuous casting is used to continuously produce products of simple cross-sectional shape such as slabs, billets or round bars from molten steel continuously. A slab or billet molded by the continuous casting method is gradually cooled while being guided and conveyed by a large number of guide rolls arranged on the front and back sides along the traveling direction. As the inner and outer rings of the guide roll bearing used for the neck portion of the guide roll may be inclined due to the deflection of the guide roll or the inclination of the housing, a self-aligning roller bearing is generally used as the guide roll bearing ing.

  By the way, since the guide roll bearing is used at extremely low speed rotation, the lubricant is less likely to be drawn between the bearing ring and the rolling element, and the oil film is less likely to be formed. In addition, since it is not possible to avoid water immersion into the bearing from the use environment, there is a possibility that the lubrication state may be deteriorated and wear may occur due to metal contact. In particular, in a self-aligning roller bearing, differential slippage is large, the amount of wear is large, and there is a possibility that separation may occur or breakage may occur.

  In order to reduce the wear of self-aligning roller bearings, form a carbonitrided layer on the surface of the bearing ring, make the retained austenite amount of this carbonitrided layer 10% by volume or more, and make the surface hardness a Rockwell hardness HRC 58 or more. Has been proposed (eg, Patent Document 1).

  Further, it has been proposed to add a diurea compound to a lubricant base oil of a grease composition for lubricating a bearing and to add a polymer compound and a succinic acid and / or a succinic acid derivative (for example, Patent Document 2). According to this configuration, the lubricating oil film in the rotation area and the sliding area can be maintained thick, and seizure and the like can be prevented to reduce damage to the bearing.

  Further, it has been proposed to provide crowning on the outer diameter surface of the outer ring of a self-aligning roller bearing and provide a clearance between the outer ring and the housing (for example, Patent Document 3). According to this configuration, when the bearing receives a load, the outer ring elastically deforms, and the contact surface pressure with the raceway surface is equalized, so it is possible to suppress uneven wear.

JP 2000-246410 A Japanese Patent Application Laid-Open No. 2003-073682 Unexamined-Japanese-Patent No. 2003-343554

However, in the technique of Patent Document 1, a large amount of alloying elements are used, and further, it is necessary to perform carbonitriding, which may increase the manufacturing cost of the bearing ring.
Further, in the technology of Patent Document 2, when a large amount of water is flooded in the bearing due to the surrounding environment, the effect may be limited.
Further, in the technology of Patent Document 3, the contact length of the fitting portion becomes short, and there is a possibility that the outer ring may be tilted with respect to the housing, which can not be said to be a sufficient countermeasure.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a cylindrical roller bearing capable of suppressing the wear of a fixed ring even when used at low speed rotation.

The above object of the present invention is achieved by the following constitution.
(1) An inner ring having an inner ring raceway surface formed on the outer peripheral surface, an outer ring having an outer ring raceway surface formed on the inner peripheral surface, and a circumferential direction capable of rolling between the inner ring raceway surface and the outer ring raceway surface Multiple cylindrical rollers,
A cylindrical roller bearing comprising
The cylindrical roller has a straight portion at least at a central portion in the axial direction,
The inner ring raceway surface and the outer ring raceway surface have a single arc crowning shape,
Assuming that the maximum diameter of the cylindrical roller is Dw, and the falling amount from the axial end of the outer ring raceway to the axial center of the outer ring raceway is A, 0.0015 ≦ A / Dw ≦ 0.0310 meet the relationship,
A cylindrical roller bearing satisfying a relational expression of A <B, where B is a drop amount from an axial center portion of the inner ring raceway surface to an axial end portion of the inner ring raceway surface .
(2) Assuming that the maximum diameter of the cylindrical roller is Dw and the axial dimension of the cylindrical roller is L, the relational expression of 1.6 ≦ L / Dw ≦ 3.0 is satisfied. Cylindrical roller bearing as described.
(3) Assuming that the maximum diameter of the cylindrical roller is Dw and the radial dimension of the cross section of the cylindrical roller bearing is H, the relational expression of 0.55 ≦ Dw / H ≦ 0.65 is satisfied ( The cylindrical roller bearing according to 1) or (2).

  According to the present invention, it is possible to obtain a cylindrical roller bearing capable of suppressing the wear of the fixed wheel even when used at low speed rotation.

It is a schematic diagram which shows the cylindrical roller bearing concerning one Embodiment of this invention. (A) is a principal part enlarged view of the outer ring | wheel of the cylindrical roller bearing of FIG. 1, (b) is a principal part enlarged view of the inner ring of the cylindrical roller bearing of FIG. It is a graph which shows the relationship between the largest surface pressure of a roller, and a roller major-diameter ratio. It is a graph which shows the relationship between the largest surface pressure of a roller, and the ratio of a largest diameter of a roller and section height. It is a graph which shows the relationship between the largest contact pressure of a roller, and the ratio A of the drop amount A of an outer ring raceway surface, and a largest diameter. It is a graph which shows the relationship between the largest surface pressure of a roller, and the amount B of falling of the inner ring raceway surface and the ratio of the largest diameter. It is the elements on larger scale for demonstrating the shape of the roller used with the cylindrical roller bearing of FIG. It is a figure which shows the relationship between the largest surface pressure of a roller, and the ratio of a crowning drop amount C and a largest diameter. It is a figure which shows the spherical roller bearing of a comparative example.

  Hereinafter, a cylindrical roller bearing according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the cylindrical roller bearing 10 according to the present embodiment is a full-roller type rolling bearing not having a cage, and an inner ring 20 having an inner ring raceway surface 22 formed on the outer peripheral surface, and a shaft A plurality of outer rings 30 are formed on both ends thereof in the direction and the outer ring raceway surface 32 is formed on the inner peripheral surface, and a plurality of inner ring raceway surfaces 22 and the outer ring raceway surface 32 are rollable circumferentially. And a disposed roller 40. The rolling surface of the roller 40 has a straight portion 42 formed in a cylindrical shape, and a crowning portion 44 formed in a convexly curved shape from both axial ends of the straight portion to an axial end face of the roller 40. Due to the crowning portion 44, the cylindrical roller bearing 10 has alignment. The material of the cylindrical roller bearing 10 may be any hardenable steel, and can be made of, for example, bearing steel, carburized steel or the like. The cylindrical roller bearing 10 is lubricated by being filled with a predetermined amount of grease, but the inside of the cylindrical roller bearing 10 becomes a sealed space by the seals 50 and 50, so the grease is less likely to be discharged to the outside There is.

  The cylindrical roller bearing 10 according to the present embodiment rotatably supports the neck portion 3 of the guide roll 1 of a continuous casting facility for forming a slab or billet with respect to the housing 5. When the slab passes through the guide roll 1, the cylindrical roller bearing 10 receives a considerably large load, but in the present embodiment, since the cylindrical roller bearing 10 is a full-roller type, the load capacity is increased. It is possible to suppress the reduction of the life of ten.

  By the way, in general, cylindrical roller bearings have an advantage that there is little differential slip, but when the bearing ring is relatively inclined due to the deflection of the guide roll 1 or the inclination of the housing 5, the outer ring (especially the fixed ring) The contact pressure at the end of the roller at the contact portion with the above tends to be excessive. However, the present inventor has found that by appropriately defining various dimensions, shapes, and the like of cylindrical roller bearings, it is possible to suppress excessive contact pressure and to significantly reduce wear.

  Further, generally, when the cylindrical roller bearing rotates, the rotational direction of the cylindrical roller bearing may not coincide with the rotational direction of the cylindrical roller bearing, and the rotation shaft of the roller may fall in the circumferential direction to cause a skew. In particular, in a full-roller type cylindrical roller bearing, the rollers are easily in contact with each other, so the occurrence of a skew becomes a problem. In the present embodiment, the roller 40 has a straight portion 42 at the axial center. According to the roller 40 having such a straight portion 42, the occurrence of skew can be suppressed compared to a roller having a crowning shape in the entire axial direction, and the surface roughness of the rolling surface (straight portion 42) Accuracy can be improved.

  Here, in the present embodiment, when the maximum diameter of the roller 40 (diameter of the straight portion 42, hereinafter referred to as roller diameter) is Dw, and the axial dimension of the roller 40 (hereinafter referred to as roller length) is L, By defining the roller long diameter ratio (L / Dw), the surface pressure at the end of the roller 40 at the contact portion with the bearing ring is suppressed. The relationship between the roller length ratio (L / Dw) and the maximum surface pressure of the roller 40 at the contact portion with the bearing ring is shown in FIG. As shown in FIG. 3, when the roller length / diameter ratio (L / Dw) is increased, the contact area between the roller 40 and the bearing ring is increased, and the range to be subjected to pressure is expanded. Becomes smaller. The contact pressure reduction effect is almost saturated at L / Dw = 1.6. In addition, when L / Dw> 3.0, the processing of the roller 40 becomes difficult, and the collar thickness is insufficient, which makes it difficult to secure sufficient collar strength. Therefore, in the present invention, the roller long diameter ratio (L / Dw) is defined as 1.6 ≦ L / Dw ≦ 3.0. The roller long diameter ratio (L / Dw) is more preferably 2.0 ≦ L / Dw ≦ 2.8.

  In the present embodiment, when the sectional height (dimension in the radial direction) of the cylindrical roller bearing 10 is H, the bearing ring is defined by defining the ratio (Dw / H) between the roller diameter Dw and the sectional height H. The surface pressure of the end portion of the roller 40 at the contact portion with can be further suppressed. The relationship between the ratio (Dw / H) of the roller diameter Dw to the cross-sectional height H and the maximum surface pressure of the roller 40 is shown in FIG. As shown in FIG. 4, as the roller diameter Dw increases, the surface pressure of the roller 40 decreases, so the contact surface pressure between the roller 40 and the bearing ring can be reduced. The contact pressure reduction effect is more effective when Dw / H ≧ 0.55. When Dw / H> 0.65, the thickness of the bearing ring becomes too thin, which makes processing difficult. Therefore, it is preferable that the roller diameter Dw and the cross-sectional height H satisfy 0.55 ≦ Dw / H ≦ 0.65.

  Further, in the present embodiment, the inner ring raceway surface 22 of the inner ring 20 and the outer ring raceway surface 32 of the outer ring 30 are formed to have a single arc crowning shape. According to the configuration, compared to the case where the crowning portion is provided at the axial end of the inner ring raceway surface 22 and the outer ring raceway surface 32, and the flat portion is provided at the axial center, the surface pressure is sharper at the end of the roller 40 It is possible to suppress the rise.

  In the present embodiment, as shown in FIG. 2A, the amount of drop from the axially central portion of the outer ring raceway surface 32 to the axial end (that is, the connection portion between the relief portion 33 and the outer ring raceway surface 32) The height difference between the axially central portion of the outer ring raceway surface 32 and the axial direction end of the outer ring raceway surface 32 (hereinafter also referred to as “the amount of outer ring drop”) is A. Then, the ratio (A / Dw) of the roller diameter Dw to the outer ring drop amount A is defined. The relationship between the ratio (A / Dw) of the roller diameter Dw to the amount A of the outer ring drop A and the maximum surface pressure of the roller 40 is shown in FIG. As shown in FIG. 5, as A / Dw increases, that is, as the outer ring drop amount A increases, the maximum surface pressure of the roller 40 decreases. The contact pressure reduction effect becomes more effective when A / Dw ≧ 0.0015 is satisfied. However, as the outer ring drop amount A increases, the edge load does not occur, but on the contrary, the surface pressure at the axial center of the outer ring raceway surface 32 increases, and the axial end of the outer ring raceway surface 32 is machined (grind , SF finish) becomes difficult. From this, A / Dw ≦ 0.0310. More preferably, 0.0020 ≦ A / Dw ≦ 0.0150. Thereby, the surface pressure of the end portion of the roller 40 at the contact portion with the outer ring 30 can be further suppressed.

  Further, in the present embodiment, as shown in FIG. 2B, the amount of drop from the axial center portion of the inner ring raceway surface 22 to the axial end portion (axial center portion of the inner ring raceway surface 22 and axial end portion Let B be the difference in height between the two, also referred to as the inner drop amount). Then, the ratio (B / Dw) of the roller diameter Dw to the inner ring drop amount B is defined as 0.0020 ≦ B / Dw ≦ 0.0550. The relationship between the ratio (B / Dw) of the roller diameter Dw to the inner ring drop amount B and the maximum surface pressure of the roller 40 is shown in FIG. As shown in FIG. 6, as B / Dw increases, that is, as the inner-ring drop amount B increases, the maximum surface pressure of the roller 40 decreases. The surface pressure reduction effect becomes more effective when B / Dw ≧ 0.0020 is satisfied. However, although the edge load does not occur as the inner ring drop amount B increases, unlike the outer ring 30 which always receives the edge load, in the case of the inner ring 20, the roller 40 where the edge load occurs is limited and the influence is small . There is also a problem that as the inner-ring drop amount B increases, the rollers 40 tend to skew. Further, as the inner ring drop amount B increases, the surface pressure at the axially central portion of the inner ring raceway surface 22 increases, and processing (grinding, SF finishing) of the axial end portion of the inner ring raceway surface 22 becomes difficult. From this, B / Dw ≦ 0.0550. More preferably, 0.0030 ≦ B / Dw ≦ 0.0260. Thereby, the surface pressure of the end portion of the roller 40 at the contact portion with the inner ring 20 can be further suppressed.

  Further, in the present embodiment, it is assumed that the outer ring drop amount A and the inner ring drop amount B satisfy A <B. In a continuous casting machine, since the guide roll 1 thermally expands during passage of a very hot slab, the cylindrical roller bearing 10 installed in the axle box stretches the guide roll 1 using the inner ring 20 not provided with a collar. It is necessary to escape axially outward. Since the flanges 34 are formed at both axial ends of the outer ring 30, even when the inner ring 20 moves in the axial direction, the relative positional relationship between the outer ring 30 and the outer ring 40 does not change. However, since the relative positional relationship between the inner ring 20 and the inner ring 40 changes, the surface pressure distribution also moves in the axial direction along with the change. When the radius R of the crowning shape of the inner ring 20 is large, the contact area between the roller 40 and the inner ring raceway surface 22 becomes wide, so when the inner ring 20 moves in the axial direction, the contact surface with the inner ring 20 and 40 is the roller 40 There is a risk that edge loading may occur due to deviation from the rolling surface. In this embodiment, by setting A <B, the contact area between the roller 40 and the inner ring raceway surface 22 can be narrowed. Therefore, even when the guide roll 1 is extended and the inner ring 20 is moved in the axial direction, the roller The contact surface pressure between the inner raceway surface 40 and the inner raceway surface 22 can be reduced to suppress the occurrence of edge loading.

  Further, in the present embodiment, as shown in FIG. 7, in the roller 40, the drop amount (crowning drop amount) from the straight portion 42 formed at the axial center to the axial end is C. The ratio (C / Dw) of the roller diameter Dw to the crowning drop amount C is defined as 0.0003 ≦ C / Dw ≦ 0.0050. The relationship between the ratio of the roller diameter Dw to the crowning drop amount C and the maximum roller surface pressure is shown in FIG. As shown in FIG. 8, as C / Dw increases, that is, as the crowning drop amount C of the roller 40 increases, the maximum surface pressure of the roller 40 decreases. The surface pressure reduction effect is more effective when 0.0005 ≦ C / Dw ≦ 0.0030 is satisfied. However, as the crowning drop amount C increases, the edge load does not occur, but conversely, the surface pressure at the axially central portion of the inner ring raceway surface 22 and the outer ring raceway surface 32 increases. In addition, when the crowning drop amount C is large, the processing (grinding and SF finishing) of the crowning portion 44 becomes difficult, so that C / Dw ≦ 0.0050 is preferable.

  Further, in the present embodiment, the surface roughness of the rolling surface of the roller 40 is smaller than the surface roughness of the inner ring raceway surface 22 and the outer ring raceway surface 32. As described above, since the continuous casting machine is operated at extremely low speed rotation, an oil film is not easily formed between the members. In particular, in the case of the full-roller type cylindrical roller bearing 10 as in the present embodiment, an oil film is less likely to be formed at the contact portion between the rollers 40 than between the rolling contact roller 40 and the bearing ring. At this time, if the surface roughness of the rolling surface of the roller 40 is small, an oil film is easily formed at the contact portion between the rollers 40, so that damage to the roller 40 can be prevented. On the other hand, even if the surface roughness of the outer ring raceway surface 32 and the inner ring raceway surface 22 is reduced, the occurrence of metal contact remains unchanged. Therefore, even if the surface roughness of the outer ring raceway surface 32 and the inner ring raceway surface 22 is somewhat large, there is no significant influence on the life. Therefore, in the present embodiment, the surface roughness of the rolling surface of the roller 40 is made smaller than the surface roughness of the inner ring raceway surface 22 and the outer ring raceway surface 32, thereby reducing damage to the roller 40 due to contact between the rollers 40. Thus, the life of the cylindrical roller bearing 10 can be improved.

  Thus, according to the cylindrical roller bearing 10 of the present embodiment, the roller maximum diameter Dw, the roller length L, the cross sectional height H of the cylindrical roller bearing 10, the outer ring drop amount A, the inner ring drop amount B, and the crowning drop amount C However, 1.6 ≦ L / Dw ≦ 3.0, 0.55 ≦ Dw / H ≦ 0.65, 0.0015 ≦ A / Dw ≦ 0.0310, 0.0020 ≦ B / Dw ≦ 0.0550, The relational expression of A <B and 0.0003 ≦ C / Dw ≦ 0.0050 is satisfied, and the surface roughness of the rolling surface of roller 40 is smaller than the surface roughness of inner ring raceway surface 22 and outer ring raceway surface 32 As a result, it is possible to obtain a cylindrical roller bearing having excellent wear resistance and improved life.

  The present invention is not limited to the above-described embodiment, and appropriate modifications, improvements, and the like can be made. For example, although the cylindrical roller bearing according to the above-described embodiment is a full-roller type rolling bearing in which a cage is not provided, a cylinder provided with cages that holds a plurality of rollers at substantially equal intervals in the circumferential direction Roller bearings are also within the scope of the present invention. According to a cylindrical roller bearing provided with a cage, the occurrence of skew can be suppressed even in a situation where the shaft tilt is large and roller skew is likely to occur, and wear and heat generation under high loads are minimized. Can be limited. Further, the cage can prevent the burrs at the time of assembling the cylindrical roller bearing.

  The cylindrical roller bearing according to the above-described embodiment is a guide roll bearing used in the continuous casting method, and the outer ring is a fixed ring and the inner ring is a drive wheel, but the inner ring is a fixed ring and the outer ring is a drive wheel The configuration may be such that

  In addition, the roller 40 may be a cylindrical roller in which a straight portion is formed over the entire axial direction. According to such a roller, the occurrence of skew can be further suppressed, and the accuracy of the surface roughness of the rolling surface can be further improved. Further, depending on the application, the cylindrical rollers 40 may be provided in double rows or three or more rows, and a cage may be provided. Further, in the above-described embodiment, the flanges 34, 34 are formed at both axial ends of the outer ring 30, but depending on the application and conditions, the collar may be formed only at one axial end of the outer ring It may be.

  In addition, the outer ring 30 or the inner ring 20 may be provided with a barre for preventing the rollers from being barred when the bearing is attached to or removed from the guide roll. Further, the crowning shape of the outer ring 30 and the inner ring 20 has a crowning shape having a plurality of circular arc shapes, a logarithmic crowning shape, and a straight shape depending on the application as long as the outer ring drop amount A and the inner ring drop amount B can be increased. It may be a shape.

As described above, the present invention has the following features.
(1) An inner ring having an inner ring raceway surface formed on the outer peripheral surface, an outer ring having an outer ring raceway surface formed on the inner peripheral surface, and a circumferential direction capable of rolling between the inner ring raceway surface and the outer ring raceway surface Multiple cylindrical rollers,
A cylindrical roller bearing comprising
The cylindrical roller has a straight portion at least at a central portion in the axial direction,
A cylindrical roller bearing, wherein the inner ring raceway surface and the outer ring raceway surface have a single arc crowning shape.
(2) Assuming that the maximum diameter of the cylindrical roller is Dw and the axial dimension of the cylindrical roller is L, the relational expression of 1.6 ≦ L / Dw ≦ 3.0 is satisfied. Cylindrical roller bearing as described.
(3) Assuming that the maximum diameter of the cylindrical roller is Dw and the radial dimension of the cross section of the cylindrical roller bearing is H, the relational expression of 0.55 ≦ Dw / H ≦ 0.65 is satisfied ( The cylindrical roller bearing according to 1) or (2).
(4) The cylindrical roller has the straight portion formed in the central portion in the axial direction, and crowning portions formed on both sides in the axial direction of the straight portion,
Assuming that the maximum diameter of the cylindrical roller is Dw and the falling amount of the crowning portion from the straight portion to the axial end of the cylindrical roller is C, a relational expression of 0.0003 ≦ C / Dw ≦ 0.0050 is obtained. The cylindrical roller bearing according to any one of (1) to (3), which is characterized by being filled.
(5) Assuming that the maximum diameter of the cylindrical roller is Dw, and the falling amount from the axial end of the outer ring raceway to the axial center of the outer ring raceway is A, 0.0015 ≦ A / Dw ≦ 0. The cylindrical roller bearing according to any one of (1) to (4), which satisfies the relational expression of .0310.
(6) Assuming that the maximum diameter of the cylindrical roller is Dw, and the falling amount from the axial end of the inner ring raceway surface to the axial central portion of the inner ring raceway surface is B, 0.0020 ≦ B / Dw ≦ 0. The cylindrical roller bearing according to any one of (1) to (5), which satisfies the relational expression of .0550.
(7) A fall amount from the axial end of the outer ring raceway surface to the axial center of the outer ring raceway surface A, and from the axial end of the inner ring raceway surface to the axial center portion of the inner ring raceway The cylindrical roller bearing according to any one of (1) to (6), wherein A <B, where B is a drop amount.
(8) The cylindrical roller bearing according to any one of (1) to (7), wherein the surface roughness of the cylindrical roller is smaller than the surface roughness of the inner ring raceway surface and the outer ring raceway surface.
(9) The cylindrical roller bearing according to any one of (1) to (3), wherein the cylindrical roller has the straight portion in the entire axial direction.

10 cylindrical roller bearing 20 inner ring 22 inner ring raceway surface 30 outer ring 32 outer ring raceway surface 40 rollers

Claims (3)

A plurality of inner rings having an inner ring raceway surface formed on the outer peripheral surface, an outer ring having an outer ring raceway surface formed on the inner peripheral surface, and a plurality of rollable circumferentially between the inner ring raceway surface and the outer ring raceway surface A cylindrical roller bearing comprising:
The cylindrical roller has a straight portion at least at a central portion in the axial direction,
The inner ring raceway surface and the outer ring raceway surface have a single arc crowning shape,
Assuming that the maximum diameter of the cylindrical roller is Dw, and the falling amount from the axial end of the outer ring raceway to the axial center of the outer ring raceway is A, 0.0015 ≦ A / Dw ≦ 0.0310 meet the relationship,
A cylindrical roller bearing satisfying a relational expression of A <B, where B is a drop amount from an axial center portion of the inner ring raceway surface to an axial end portion of the inner ring raceway surface .   The cylinder according to claim 1, satisfying the relational expression 1.6 ≦ L / Dw ≦ 3.0, where Dw is the maximum diameter of the cylindrical roller and L is the axial dimension of the cylindrical roller. Roller bearing.   The relational expression of 0.55 ≦ Dw / H ≦ 0.65 is satisfied, where Dw is the maximum diameter of the cylindrical roller, and H is the radial dimension of the cross section of the cylindrical roller bearing. The cylindrical roller bearing according to 2.

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