JP2004084938A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satisfactory rolling bearing which prevents a flaw caused on the circumferential surface of a shaft by the rubbing with a ridge part on each inside surface of a pair of inner rings which are fitted to the shaft in the state where their axial end surfaces are mutually butted. <P>SOLUTION: A double row bearing for rolling stock has a pair of inner rings 33 and 34 fitted to the shaft 1 in the state where butt end surfaces 33a and 34a are mutually butted. The inside surface of each inner ring 33 or 34 has a cylindrical straight part 33c or 34c to which the shaft is tightly fitted, and an insert guide surface 33b or 34b formed on the inside surface edge continued to the end surface 33a or 34a. When the distance between ridge parts 38 and 39 each of which is the intersection of the straight part 33c or 34c and the insert guide surface 33b or 34b in each inner ring 33 or 34 is L and the diameter of the shaft 1 is d, the relation between the distance L and the diameter D is set to L/d<0.03. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, and more particularly, to an improvement for preventing scratches generated on an outer peripheral surface of a shaft due to friction between the inner peripheral surfaces of a pair of inner rings fitted to the shaft with their axial end surfaces abutting each other. It is about.
[0002]
[Prior art]
2. Description of the Related Art In the related art, there is known a railway vehicle axle support structure including a railway vehicle axle double row bearing (for example, see Patent Document 1).
The railway vehicle axle support structure shown in FIG. 12 is a railway vehicle axle (hereinafter, also simply referred to as an axle) 1 rotatably supported by a railway vehicle axle double-row bearing (hereinafter, also simply referred to as a double-row bearing) 3. It is.
[0003]
The double-row bearing 3 for an axle of a railway vehicle has a pair of inner rings 11 and 12 divided in the axial direction, a single outer ring 14, and a plurality of pieces provided between the inner rings 11 and 12 and the outer ring 14. The configuration includes a rolling element 15 and retainers 16 and 17 for holding the rolling elements 15 between the inner and outer rings at equal intervals. In the illustrated example, the rolling elements 15 are tapered rollers.
[0004]
The pair of inner rings 11 and 12 are used in a contact state in which opposing ends of the inner rings 11 and 12 abut against each other, and the shaft 1 is fitted to the inner periphery of the inner rings 11 and 12.
As shown in FIG. 13, each of the inner races 11 and 12 has a tapered insertion guide that gradually increases in diameter toward the butting end faces 11a and 12a at an inner peripheral surface edge continuous with the butting end faces 11a and 12a. Surfaces 11b and 12b are formed and serve as guide surfaces when the bearing is inserted into the shaft 1.
[0005]
That is, the inner peripheral surfaces of the inner rings 11 and 12 include cylindrical straight portions 11c and 12c having a fixed inner diameter and the shaft 1 being tightly fitted, and insertion guide surfaces 11b and 12b connected to the butted end surfaces 11a and 12a. It has a structured structure.
The inner rings 11 and 12 are arranged between a front slinger 21 fitted to the shaft 1 and a rear slinger 23 fitted to the shoulder 1a of the shaft 1. The two inner rings 11 and 12 are press-fitted and fixed due to a dimensional difference between the inner ring inner diameter and the shaft.
[0006]
On the shaft end of the shaft 1, a small lid 25 having a rotation preventing protrusion 25 a protruding from the inner peripheral surface is mounted in a state where the rotation preventing protrusion 25 a is engaged with the locking groove 1 b on the outer periphery of the shaft 1. I have. By connecting and integrating the small lid 25 and the front lid 24 with the bolts 27, the rotation of the front lid 24 becomes impossible, and the front lid 24 is prevented from loosening.
Further, on both sides of the double-row bearing 3, contact-type sealing devices 28 are mounted, which prevent foreign substances from entering the double-row bearing 3 and leakage of lubricant from the inside of the bearing. Have been.
[0007]
[Patent Document 1]
JP-A-7-293570
[Problems to be solved by the invention]
By the way, as shown in FIG. 13, in each of the inner races 11, 12, the intersections between the cylindrical straight portions 11 c, 12 c and the insertion guide surfaces 11 b, 12 b are obtuse ridges 18, 19.
Generally, the railcar axle 1 is slightly bent due to a load from a bogie or a vehicle body, and is bent (bent), and is rotated and driven in a bent state.
[0009]
Therefore, when the shaft 1 rotates, a small amount of repeated sliding occurs between the ridges 18, 19 and the shaft 1, and the outer circumferential surface of the shaft 1 on which the ridges 18, 19 are rubbed has a circumferential surface due to fretting wear. Scratches along the direction occur. Particularly, in the axle of the railway vehicle, the damage is remarkable near the ridge 19 of the inner ring 12 of the bearing 3 on the side near the shoulder 1a of the shaft 1. Such fretting tends to occur more frequently when the inner rings 11, 12 and the railcar axle 1 are fitted without lubrication.
When such a flaw occurs, if the flaw can be corrected, the flaw portion of the shaft 1 is corrected and reused, which is troublesome. Further, if the scratches have a depth equal to or more than a certain depth, the shaft 1 is discarded, which is uneconomical.
[0010]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and the outer periphery of the shaft is rubbed against the ridges of the inner peripheral surfaces of a pair of inner races that are fitted to the shaft with their axial end faces abutting each other. An object of the present invention is to provide a good rolling bearing capable of preventing a surface from being damaged.
[0011]
[Means for Solving the Problems]
The object of the present invention is to provide a pair of inner races which are fitted to a shaft in a state where the end faces in the axial direction abut each other, and the inner peripheral surface of each inner race has a cylindrical straight portion in which the shaft is tightly fitted. And an insertion guide surface formed on an edge of an inner peripheral surface continuous with the end surface, wherein the ridge line portion is an intersection of the straight portion and the insertion guide surface in each of the inner rings. Where L is the distance of the shaft and d is the diameter of the shaft, the relationship between the distance L and the diameter d is L / d <0.03.
[0012]
According to the above configuration, the edge load (surface pressure) at the ridge portion of each inner ring is reduced, thereby preventing the outer circumferential surface of the shaft from being damaged along the circumferential direction due to fretting wear. it can.
[0013]
In the above-mentioned rolling bearing, when the axial length of the insertion guide surface in each of the inner rings is l ₁ and l ₃ , respectively, l ₁ > 0.1 [mm] and l ₃ > 0. By setting it to 1 [mm], the workability of the inner ring does not need to be reduced.
[0014]
Further, in the above-mentioned rolling bearing, the inner ring arranged at least on the side closer to the shoulder of the shaft is provided with a cutout portion at a shoulder where the end face and the outer peripheral surface of the inner ring intersect. Thereby, the volume of the shoulder of the inner race can be reduced, and the tightening force due to the hoop stress of the insertion guide surface can be reduced.
[0015]
Further, the object of the present invention is to provide a pair of inner races which are fitted to the shaft in a state where the end faces in the axial direction abut each other, and the inner peripheral surface of each inner race has a cylindrical shape in which the shaft is tightly fitted. A rolling bearing provided with a straight portion and an insertion guide surface formed at an edge of an inner peripheral surface continuous with an end surface, wherein the inner ring disposed at least on a side closer to a shoulder of the shaft has the end face. The rolling bearing is characterized in that a cut-out portion is provided at a shoulder where the outer surface of the inner ring intersects with the outer ring.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a rolling bearing according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view of a railcar axle support structure provided with a rolling bearing according to a first embodiment of the present invention, and FIG. 2 is an enlarged schematic view of a portion B in FIG.
The railway vehicle axle double row bearing 31 of this embodiment is a rolling bearing having the same configuration as the conventional railway vehicle axle double row bearing 3 described with reference to FIGS. Only parts different from the row bearing 3 will be described, and detailed description of the same parts will be omitted.
[0017]
The double-row bearing 31 for a railway vehicle axle according to the first embodiment of the present invention shown in FIG. 1 includes a pair of inner rings 33 and 34 divided in the axial direction, a single outer ring 14, and each inner ring 33 and 34. And a plurality of rolling elements 15 provided between the inner ring and the outer ring 14, and retainers 16 and 17 for holding the rolling elements 15 between the inner and outer rings at equal intervals.
[0018]
The pair of inner rings 33 and 34 are used in a contact state in which opposing ends thereof are abutted with each other, and the shaft 1 is fitted to the inner periphery of the inner rings 33 and 34.
As shown in FIG. 2, each of the inner races 33, 34 has a tapered insertion guide that gradually increases in diameter toward the butting end faces 33a, 34a at an inner peripheral surface edge continuous with the butting end faces 33a, 34a. Surfaces 33b and 34b are formed and serve as guide surfaces when the bearing is inserted into the shaft 1.
[0019]
That is, the inner peripheral surfaces of the inner rings 33, 34 include cylindrical straight portions 33c, 34c having a fixed inner diameter and the shaft 1 tightly fitted thereto, and insertion guide surfaces 33b, 34b connected to the butted end surfaces 33a, 34a. The intersections between the cylindrical straight portions 33c, 34c and the insertion guide surfaces 33b, 34b are obtuse ridges 38, 39.
[0020]
When the distance between the ridge 38 on the inner ring 33 side and the ridge 39 on the inner ring 34 side is L and the diameter of the shaft 1 is d, the relationship between the distance L and the diameter d is L /D<0.03. That is, the axial length of the insertion guide surface 34b of the insertion guide surface 33b and the inner ring 34 side of the inner ring 33 side upon a _l 3, _{l 1, respectively,} as _{l 1 = l 3, l 1} / d <0 .015.
Thereby, the edge load (surface pressure) at the ridge portions 38 and 39 is reduced, and it is possible to prevent the circumferential surface of the shaft 1 from being damaged by fretting wear.
[0021]
FIG. 3 is a longitudinal sectional view of a railway vehicle axle support structure including a rolling bearing according to a second embodiment of the present invention, and FIG. 4 is an enlarged schematic view of a portion C in FIG.
The double row bearing 51 for a railway vehicle axle of the present embodiment is a rolling bearing having the same configuration as the railway vehicle axle bearing 31 of the first embodiment described with reference to FIGS. 1 and 2. The bearing 51 according to the second embodiment of the present invention shown in FIG. 3 includes a plurality of rolling elements 15 provided between a pair of inner rings 53 and 54 and a single outer ring 14, and retainers 16 and 17. This is a configuration including:
[0022]
As shown in FIG. 4, the bearing 51 cuts off the shoulders of the inner ring 53 and the inner ring 54 where the butted end surfaces 53a, 54a of the inner rings 53, 54 intersect with the outer peripheral surface in a shape having a substantially rectangular cross section. Are provided with steps 53d and 54d, which are cutout portions, to reduce the shoulder volume of the inner ring.
[0023]
The inner peripheral surfaces of the inner rings 53, 54 include cylindrical straight portions 53c, 54c having a fixed inner diameter and tightly fitted with the shaft 1, and insertion guide surfaces 53b, 54b connected to the butted end surfaces 53a, 54a. The intersection between the cylindrical straight portions 53c, 54c and the insertion guide surfaces 53b, 54b forms obtuse ridges 58, 59. Assuming that the distance between the ridge portions 58 and 59 is L and the diameter of the shaft 1 is d, L / d <0.03 as in the first embodiment. When the lengths of the insertion guide surfaces 53b and 54b in the axial direction are l ₃ and l ₁ , respectively, l ₁ = l ₃ and l ₁ /d<0.015.
[0024]
As described above, in the second embodiment, the tightening force due to the hoop stress of the insertion guide surface 53b on the inner ring 53 side and the insertion guide surface 54b on the inner ring 54 side can be reduced by reducing the volume of the shoulder of the inner ring. Therefore, the edge load at the ridge portions 58 and 59 is reduced, and it is possible to prevent the circumferential surface of the shaft 1 from being damaged by fretting wear. It should be noted that the shape of the shoulder of the inner ring is not limited to a rectangle, but may be any shape. In addition, by using the configuration in which the cut-out portion is provided on the shoulder of the inner ring in combination with the relationship between the distance of the ridge portion and the diameter of the shaft, the edge load at the ridge portions 58 and 59 can be further reduced, and the fretting wear is reduced. The effect can be improved.
[0025]
FIG. 5 is an enlarged sectional view of a main part of a railcar axle support structure provided with a rolling bearing according to a third embodiment of the present invention. The third embodiment is different from the first embodiment in that the shoulder of the inner ring 63 is not provided with a step, and the shoulder of the inner ring 64 is provided with a step 64d cut in a shape close to a rectangle, thereby reducing the shoulder volume of the inner ring. Different from the second embodiment. That is, in the third embodiment, the shoulder volume of only the inner ring 64 near the shoulder 1a of the axle 1 is reduced. Accordingly, it is not necessary to provide a step on each of the pair of inner rings, and the volume can be reduced by providing a step only on the shoulder of the inner ring on the outer surface of the shaft 1 on which the flaws due to fretting wear are likely to occur.
Also in this case, by using the above configuration in combination with the relationship between the distance between the ridge portions and the diameter of the shaft in the first embodiment, the edge load at the ridge portions 58 and 59 can be further reduced, and the fretting wear is reduced. Can be improved.
[0026]
Next, when the relationship between the distance L and the diameter d is l ₁ = l ₃ , L / d <0.03 (= l ₁ /d<0.015). Two reasons why the edge load at the ridge portions 38 and 39 can be reduced will be described.
First, the contact surface pressure between the shaft 1 and the inner races 33 and 34 is generated by the tightening force due to the hoop stress of the inner races 33 and 34. The insertion guide surface 33b on the inner race 33 side and the insertion guide surface 34b on the inner race 34 side are Since it does not come into contact with 1, the tightening force of this portion needs to be received by the other fitting surfaces (straight portions 33c, 34c), and a high edge load occurs on the ridge lines 38, 39.
[0027]
That is, the first reason is that if the axial lengths l ₃ and l ₁ of the insertion guide surface 33b on the inner ring 33 side and the insertion guide surface 34b on the inner ring 34 side are reduced, the hoop stress in this portion is reduced. As a result, the edge load at the ridge portions 38 and 39 is reduced.
Therefore, in order to examine the effect of the edge load relief by shortening the axial length l _3, l _1, when equal to the axial length l ₃ and l ₁ by the axisymmetric analysis of the finite element method, The relationship between the ratio (l ₁ / d) of the axial length l ₁ to the diameter d of the shaft 1 (l ₁ / d) and the edge load was examined.
[0028]
In the above analysis, one inner ring (single row) used in an inner ring split type double row tapered roller bearing (inner diameter 125 mm × outer diameter 235 mm × width 165 mm) was used. The axial length l ₁ of the inner ring of this size is about l ₁ = 0.008 × d for a small one, and about l ₁ = 0.08 × d for a large one.
FIG. 6 shows the analysis results. The vertical axis indicates the surface pressure ratio when the edge load (surface pressure) at the ridgeline portion is 1 when l ₁ = 0.08 × d (based on the case where l ₁ is long).
From FIG. 6, it can be seen that the edge load decreases as l ₁ / d decreases.
[0029]
Next, the second reason is that, by configuring the relationship between the distance L and the diameter d so that L / d <0.03, each inner ring is affected by deforming the shaft, and as a result, The edge load is reduced.
FIG. 7 shows a deformed shape of the shaft 1 when the distance L between the ridges 38 and 39 is long, and FIG. 8 shows a deformed shape of the shaft 1 when the distance L between the ridges 38 and 39 is short. That is, the swelling amount Δ1 of the shaft 1 when the distance L is long is larger than the swelling amount Δ2 of the shaft 1 when the distance L is short, and accordingly, a high edge load is generated.
[0030]
The same conditions as in the previous analysis (Fig. 6) performed on one inner ring (single row) to see the effect of each inner ring fitted to the shaft with their axial end faces abutting each other Then, analysis was performed on a pair of inner rings (double rows). FIG. 9 shows the analysis result. Note that, in this analysis, the analysis is performed under the condition that the end faces of the inner rings are in direct contact with each other, and has a relationship of 2 × l ₁ = L.
[0031]
It is clear from FIG. 9 that the pair of inner races respectively deform the shaft, so that the edge load is reduced as compared with the case of a single row. However, if the axial length l ₁ of the inner ring is long (when the distance L is long), the degree of the edge load relieving is small. When l ₁ /d<0.08, it can be said that there is almost no difference in the edge load between the single row and the double row.
[0032]
Shows the relationship between the distance L and the edge load 10 (where FIG. 10 is obtained by replacing the axial length l ₁ in the horizontal axis at the double row of FIG. 9 to the distance L).
From FIG. 10, by setting the relationship between the distance L and the diameter d to be L / d <0.03, the edge length is compared with the case where the axial length l ₁ is l ₁ = 0.08 × d. It is clear that the load has been reduced by 60%. Therefore, the relationship between the distance L and the diameter d is L / d <0.03.
In addition, the durability was tested using an inner ring where d = 60 [mm], L = 2 [mm], and l ₁ = l ₃ = 1 [mm], that is, an inner ring with L / d = 0.033. Was done. As a result, it was confirmed that the service life was about three times as long as the service life required by the customer (the time until the fretting wear occurred on the outer periphery of the axle). L / d <0.03 is preferable in consideration of the safety factor, having a life three times as long as the required life and also considering processing tolerances.
[0033]
Note that the configuration of the rolling bearing of the present invention is not limited to the configuration of the above-described embodiment, and it goes without saying that various configurations can be adopted based on the spirit of the present invention.
For example, in the first embodiment, the case where the butted end surfaces 33a and 34a of the inner races 33 and 34 are in direct contact with each other is taken as an example. Instead, as shown in FIG. , the end face 41a of 42, may be interposed an axial length between seat 40 _{l 2} between 42a.
[0034]
In this case, the relationship between the distance L between the ridge 48 on the inner ring 41 side and the ridge 49 on the inner ring 42 and the diameter d of the shaft 1 is L / d <0.03. each axial length l ₁ and the axial length l ₂ both in the insertion guide surface 42b of the small flange of the insertion guide surface 41b and the inner ring 42 of the small rib side, it is necessary to shorten.
In addition, in the case of each of the inner races 53 and 54 in the second embodiment and each of the inner races 63 and 64 in the third embodiment, a spacer may be interposed similarly.
Further, as described in claim 2, in the bearing according to claim 1, L / d <0.03, l ₁ > 0.1 [mm] in consideration of the workability of the inner ring, and , L ₃ > 0.1 [mm].
[0035]
Further, as shown in FIG. 2, when the chamfer lengths provided on the butted end surfaces 33a, 34a of the inner rings 33, 34 are r1 and r3, respectively, the workability when the bearing is incorporated into the axle is taken into consideration. It is more preferable that r1> 1 [mm] and r3> 1 [mm]. The same can be said for the bearings of all the embodiments described above.
[0036]
Further, in the above embodiment, the case where the present invention is applied to the inner ring split type double row bearing is taken as an example, but the invention is not limited to this, and the inner ring is provided with a pair of inner rings fitted to the shaft in abutting state. The present invention can also be applied to combined bearings.
Further, in the above embodiment, it is assumed that the axial length l ₁ of the insertion guide surfaces of the inner ring as the same size, the relationship between the diameter d and the distance L and L / d <0.03 On the condition, the axial lengths l ₃ and l ₁ of the insertion guide surfaces of the respective inner rings may be different.
Shorten only l _1, If shortening the l _3, increase the amount of bulging of the axis of l ₃ side, also affecting the shaft of l ₁ side, since the edge load of l ₁ side becomes high, It is necessary to satisfy L / d <0.03.
[0037]
The present invention is not limited to bearings for railway vehicle axles, but can be applied to automotive axle bearings, bearings for steel and industrial machinery, etc., and rolling bearings are not limited to double-row tapered roller bearings. The present invention is applicable to all rolling bearings that are used by fitting to a shaft in a state where end faces of a row cylindrical roller bearing, an angular ball bearing, and the like are abutted with each other, and is effective when used for a shaft where bending occurs. In particular, it is effective in the case where vibration is generated as in the case of transfer equipment such as a railway vehicle and an automobile.
[0038]
【The invention's effect】
As described above, according to the above-described rolling bearing of the present invention, the relationship between the distance L between the ridges of each inner ring and the diameter d of the shaft is set to L / d <0.03, so that the ridges of each inner ring are formed. Edge load (surface pressure) is reduced, thereby preventing circumferential flaws due to fretting wear on the outer peripheral surface of the shaft.
Therefore, it is possible to reduce the number of times of the repair processing for correcting the flaw portion of the shaft, and it is also possible to reduce the frequency of the periodic inspection for detecting the flaw. In addition, the life of the shaft can be extended and the maintenance cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a railway vehicle axle support structure including a rolling bearing according to a first embodiment of the present invention.
FIG. 2 is an enlarged schematic view of a portion B in FIG. 1;
FIG. 3 is a longitudinal sectional view of a railcar axle support structure provided with a rolling bearing according to a second embodiment of the present invention.
FIG. 4 is an enlarged schematic view of a portion C in FIG. 3;
FIG. 5 is an enlarged schematic view of a main part of a railcar axle support structure including a rolling bearing according to a third embodiment of the present invention.
FIG. 6 is a graph showing a relationship between a ratio (l ₁ / d) of an axial length l ₁ and a diameter d of a shaft on an insertion guide surface of an inner ring, and a surface pressure ratio at a ridge portion.
FIG. 7 is an explanatory diagram for explaining a deformed shape of a shaft when a distance L between ridge portions of each inner ring is long.
FIG. 8 is an explanatory diagram for explaining a deformed shape of a shaft when a distance L between ridge portions of each inner ring is short.
FIG. 9 shows the ratio (l ₁ / d) between the axial length l ₁ and the shaft diameter d on the insertion guide surface of each inner ring under the condition that the end faces of a pair of inner rings (double row) are in direct contact with each other. It is a graph which shows the relationship with the surface pressure ratio in a ridgeline part.
FIG. 10 is a graph showing the relationship between the ratio (L / d) between the distance L between the ridges of each inner ring and the diameter d of the shaft, and the surface pressure ratio at the ridges.
FIG. 11 is a cross-sectional view of a main part of a rolling bearing according to another embodiment of the present invention.
FIG. 12 is a cross-sectional view showing a conventional double-row bearing for a railway vehicle axle.
FIG. 13 is an enlarged schematic view of a portion A in FIG.
[Explanation of symbols]
1 railway vehicle axle (axis)
31,51,61 Double row bearings for rolling stock axles (rolling bearings)
33, 34, 53, 54, 63, 64 Inner rings 33a, 34a, 53a, 54a, 63a, 64a Butt end surfaces 33b, 34b, 53b, 54b, 63b, 64b Insert guide surfaces 33c, 34c, 53c, 54c, 63c, 64c Straight parts 38, 39, 58, 59, 68, 69 Ridge parts 53d, 54d, 64d Inner ring shoulder step (cut-out part)

Claims (4)

A pair of inner races are fitted to the shafts with their axial end surfaces abutting each other. The inner peripheral surface of each inner race has a cylindrical straight portion in which the shafts are tightly fitted, and an inner periphery connected to the end surfaces. A rolling bearing provided with an insertion guide surface formed at a surface edge,
When the distance between the ridges, which are the intersections of the straight portion and the insertion guide surface, in each of the inner rings is L, and the diameter of the shaft is d, the relationship between these distances L and the diameter d is L / L. A rolling bearing, wherein d <0.03. When the axial length of the insertion guide surface in each of the inner rings is l ₁ and l ₃ , respectively, l ₁ > 0.1 [mm] and l ₃ > 0.1 [mm]. The rolling bearing according to claim 1, wherein: The rolling according to claim 1, wherein the inner ring arranged at least on a side closer to a shoulder of the shaft is provided with a cutout at a shoulder where the end face and the outer peripheral surface of the inner ring intersect. 3. bearing. A pair of inner races are fitted to the shafts with their axial end surfaces abutting each other. The inner peripheral surface of each inner race has a cylindrical straight portion in which the shafts are tightly fitted, and an inner periphery connected to the end surfaces. A rolling bearing provided with an insertion guide surface formed at a surface edge,
A rolling bearing, wherein at least the inner ring disposed on the side near the shoulder of the shaft is provided with a cutout at a shoulder where the end face and the outer peripheral surface of the inner ring intersect.

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