JP2008169885A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device having improved strength and durability while solving conflicting issues of constructing the device to be lighter and more compact and to be more rigid at the same time. <P>SOLUTION: The wheel bearing device comprises double-row tapered roller trains 9, 10, and an inner ring 3 fixed with the end of a small diameter stepped portion 2b of a hub ring 2 rockingly caulked. A pitch circle diameter PCDo of the tapered roller train 9 on the outer side out of the double-row tapered roller trains 9, 10, is set to be larger than a pitch circle diameter PCDi of the tapered roller train 10 on the inner side, the roller length Lo thereof is set to be longer than that on the inner side (Lo>Li), a roller diameter do thereof is set to be smaller than that on the inner side (do<di), and the number thereof is set to be greater than that on the inner side. This achieves lighter and more compact construction, secures the basic rated load of a bearing train on the inner side, and improves the rigidity and life of the bearing without increasing the outer diameter of an outward member 1 on the outer side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that is reduced in weight and increased in rigidity.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. On the other hand, double row tapered roller bearings are used in vehicles such as off-road cars and trucks that have a heavy vehicle body weight.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint.

  Among these, a wheel bearing device as shown in FIG. 3 is known. The wheel bearing device includes a hub wheel 50 and a wheel bearing 51 fixed to the hub wheel 50. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  The hub wheel 50 integrally has a wheel mounting flange 52 for attaching a wheel (not shown) to one end portion on the outer side, and a small-diameter step portion 50a extending from the wheel mounting flange 52 in the axial direction is formed. . Hub bolts 52a are planted on the wheel mounting flange 52 at equal intervals in the circumferential direction.

  The wheel bearing 51 is press-fitted into the small-diameter step portion 50a of the hub wheel 50, and is fixed in the axial direction by a caulking portion 53 formed by plastically deforming an end portion of the small-diameter step portion 50a. The wheel bearing 51 has a vehicle body mounting flange 54c integrally attached to a knuckle (not shown) on the outer periphery, and an outer member having double row outer rolling surfaces 54a and 54b formed on the inner periphery. 54, a pair of inner races 55, 56 formed on the outer periphery with inner rolling surfaces 55a, 56a facing the double row outer rolling surfaces 54a, 54b, and the double row accommodated between these rolling surfaces. It is constituted by a double row tapered roller bearing provided with tapered roller 57, 58 rows and retainers 59, 60 for holding these tapered rollers 57, 58 in a freely rolling manner.

Here, the pitch circle diameter D1 of the outer side tapered roller 57 row is set larger than the pitch circle diameter D2 of the inner side tapered roller 58 row. Along with this, the inner rolling surface 55a of the inner ring 55 on the outer side is enlarged in diameter than the inner rolling surface 56a of the inner ring 56 on the inner side, and the outer rolling surface 54a on the outer side of the outer member 54 is The diameter is larger than that of the outer rolling surface 54b on the side. A larger number of outer tapered rollers 57 are accommodated than the inner tapered rollers 58, and the diameters of these rollers are set to be the same. In this way, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device can be extended. (For example, refer to Patent Document 1).
JP 2004-108449 A

  In such a conventional wheel bearing device, the pitch circle diameter D1 of the outer side tapered roller 57 row is set to be larger than the pitch circle diameter D2 of the inner side tapered roller 58 row. Since a larger number of rollers 57 are accommodated than the inner side tapered rollers 58, the rigidity of the outer side bearing row is improved, and the life of the wheel bearing device can be extended. However, in this conventional wheel bearing device, the basic rated load of the inner side bearing row becomes smaller than the basic rated load of the outer side bearing row, resulting in a short life.

  Further, since a brake drum (not shown) or the like is disposed on the outer side of the outer member 54 on the outer side, the pitch circle diameter D1 of the outer side tapered roller 57 row is increased to increase the rigidity of the bearing row. Since there is a dimensional restriction to increase the outer diameter, it is difficult to increase the outer diameter of the outer member 54 on the outer side. Therefore, it has been a challenge to further improve the rigidity, strength and durability of the bearing while suppressing an increase in the weight of the apparatus.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that simultaneously solves the conflicting problems of lightweight, compact and high rigidity of the device, and has improved strength and durability. The purpose is to do.

  In order to achieve the object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member and a wheel mounting flange for mounting a wheel at one end are integrally formed, a hub wheel having a small-diameter step portion formed on the outer periphery, and press-fitted into the small-diameter step portion of the hub wheel, and An inner member composed of at least one inner ring formed with an inner rolling surface facing the outer rolling surface of the row, and is accommodated in a freely rollable manner between both rolling surfaces of the inner member and the outer member. In the wheel bearing device provided with the double row tapered roller row, the pitch circle diameter of the outer side tapered roller row of the double row tapered roller row is larger than the pitch circle diameter of the inner side tapered roller row. The roller length of the outer tapered roller row set to the diameter The roller length of the inner side tapered roller row is set to be longer than the roller length of the outer side tapered roller row, and the outer diameter is set to be smaller than the roller diameter of the inner side tapered roller row. The number of rollers in the tapered roller row on the side is set larger than the number of rollers in the tapered roller row on the inner side.

  Thus, in the wheel bearing device of the second or third generation structure provided with the double row tapered roller row, the pitch circle diameter of the outer side tapered roller row out of the double row tapered roller row is the inner side cone. The roller diameter is set to be larger than the pitch circle diameter of the roller train, the roller length of the outer tapered roller train is set longer than the roller length of the inner tapered roller train, and the outer tapered roller train is set. Light weight because the diameter is set smaller than the roller diameter of the inner side tapered roller row and the number of rollers in the outer side tapered roller row is set larger than the number of rollers in the inner side tapered roller row.・ Providing wheel bearing devices that are compact and secure the basic load rating of the inner bearing row and improve the rigidity and life of the bearing without increasing the outer diameter of the outer member. To do It can be.

  Further, as in the invention described in claim 2, the outer side inner rolling surface is directly formed on the outer periphery of the hub wheel, and the small-diameter step portion extending in the axial direction from the inner rolling surface is formed. If the inner ring is press-fitted into the small-diameter step portion through a predetermined scissors, the strength of the hub ring can be increased and the device can be further reduced in weight and size.

  If the two inner rings are press-fitted into the small-diameter step portion of the hub wheel and the inner diameters of these inner rings are set to the same size as in the invention described in claim 3, the small-diameter step portion has a straight shape. Can be integrally processed, and the number of processing steps can be simplified and the cost can be reduced.

  Further, as in the invention described in claim 4, if the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming the end portion of the small diameter step portion radially outward, the weight is further reduced.・ Compact size can be achieved.

  The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange to be attached to the knuckle on the outer periphery, a double row outer rolling surface formed on the inner periphery, and a wheel at one end. A hub wheel integrally having a wheel mounting flange for mounting a small diameter stepped portion on the outer periphery, and press-fitted into the small diameter stepped portion of the hub wheel, facing the outer circumferential rolling surface of the double row on the outer periphery. An inner member composed of at least one inner ring formed with an inner rolling surface, and a double row conical roller row accommodated so as to roll between the inner member and both rolling surfaces of the outer member. In the wheel bearing device provided, a pitch circle diameter of an outer side tapered roller row of the double row tapered roller rows is set larger than a pitch circle diameter of an inner side tapered roller row, and the outer side The roller length of the tapered roller row is the tapered roller on the inner side. A roller diameter of the outer side tapered roller row is set to be smaller than a roller diameter of the inner side tapered roller row, and the roller of the outer side tapered roller row is set. Since the number of rollers is set to be larger than the number of rollers in the inner side tapered roller row, it is possible to reduce the weight and size, ensure the basic load rating of the inner side bearing row, and secure the outer member on the outer side of the outer member. A wheel bearing device in which the rigidity and life of the bearing are improved without increasing the outer diameter can be provided.

  A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub ring having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub ring An inner member composed of an inner ring that is press-fitted into a stepped portion and has an inner rolling surface formed on the outer periphery facing the other of the double row outer rolling surfaces, and both rolling of the inner member and the outer member. A plurality of conical roller rows that are rotatably accommodated between the surfaces, and the inner ring is formed into the hub ring by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward. In the wheel bearing device fixed in the axial direction, the out of the double row tapered roller rows. The pitch circle diameter of the negative side tapered roller row is set to be larger than the pitch circle diameter of the inner side tapered roller row, and the roller length of the outer side tapered roller row is set to the roller of the inner side tapered roller row. The roller diameter of the outer side tapered roller row is set to be smaller than the roller diameter of the inner side tapered roller row, and the number of rollers of the outer side tapered roller row is set to be longer than the length. More than the number of rollers in the inner side tapered roller row is set.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention.
This wheel bearing device is for a driving wheel called the third generation, and is composed of an outer member 1, a hub wheel 2, and an inner ring 3 press-fitted into the small-diameter step portion 2b of the hub wheel 2. And a member 4.

  The outer member 1 integrally has a vehicle body mounting flange 1c to be attached to the knuckle N constituting the suspension device on the outer periphery, and double row outer rolling surfaces 1a, 1b are formed on the inner periphery. This outer member 1 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 1a and 1b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured.

  The hub wheel 2 integrally has a wheel mounting flange 5 for mounting a wheel (not shown) and a brake drum B at an outer side end portion, and has an outer periphery that is inwardly facing the outer side rolling surface 1a. A running surface 2a and a small diameter step portion 2b extending in the axial direction from the inner rolling surface 2a are formed, and a serration (or spline) 2e for torque transmission is formed on the inner periphery. Hub bolts 6 are planted in the circumferential direction of the wheel mounting flanges 5, and circular holes 5 a are formed between the hub bolts 6. This circular hole 5a can not only contribute to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 5a in the assembly / disassembly process of the apparatus, and the work can be simplified.

  On the other hand, the inner ring 3 is formed with an inner rolling surface 3a facing the outer rolling surface 1b on the inner side on the outer periphery, and is press-fitted into the small-diameter step portion 2b of the hub wheel 2 through a predetermined shimoshiro. The (front) side end face 3d abuts against the shoulder 2c of the hub wheel 2 in a butted state to constitute a so-called back-to-back type double row tapered roller bearing. Further, the inner ring 3 is fixed in the axial direction by a caulking portion 2d formed by plastically deforming an end portion of the small diameter step portion 2b radially outward.

  The hub wheel 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and has a small diameter from a seal land portion 5b in sliding contact with a seal 11 described later via an inner rolling surface 2a and a shoulder portion 2c. The surface hardness is hardened to a range of 58 to 64 HRC by induction hardening over the step 2b. The caulking portion 2d is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 5, the fretting resistance of the small-diameter stepped portion 2b that becomes the fitting portion of the inner ring 3 is improved, and caulking is performed. The plastic working of the portion 2d can be performed smoothly while preventing the occurrence of minute cracks and the like.

  Double row tapered rollers 9, 10 are interposed between retainer 7, 8 between double row outer rolling surfaces 1 a, 1 b of outer member 1 and inner rolling surfaces 2 a, 3 a of hub ring 2 and inner ring 3. It is housed so that it can roll freely. Seals 11 and 12 are attached to the opening portion of the annular space formed between the outer member 1 and the hub wheel 2 and the inner ring 3, and leakage of grease sealed inside the bearing to the outside, Prevents rainwater and dust from entering the bearing. The inner ring 3 and the tapered rollers 9 and 10 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  Inner rolling surfaces 2 a and 3 a of the hub ring 2 and the inner ring 3 are formed in a tapered shape that makes line contact with the tapered rollers 9 and 10. And the large collars 2f and 3b for guiding the tapered rollers 9 and 10 to the large diameter side of these inner rolling surfaces 2a and 3a, and the small collar 2g for preventing the tapered rollers 9 and 10 from falling off on the small diameter side. 3c are formed respectively.

  An outer joint member 13 constituting a constant velocity universal joint (not shown) is inserted into the hub wheel 2. The outer joint member 13 integrally has a shaft portion 15 extending in the axial direction from the shoulder portion 14, and a serration (or spline) 15 a is formed on the outer periphery of the shaft portion 15, and a male screw 15 b is formed on the end portion. Then, the outer joint member 13 is inserted into the hub wheel 2 until the shoulder portion 14 abuts against the caulking portion 2d of the hub wheel 2, and both the serrations 2e and 15a are engaged, and the male screw 15b is fixed to the fixing nut. The hub wheel 2 and the outer joint member 13 are connected to each other so that torque can be transmitted and the shaft 16 can be separated in the axial direction.

  Here, in this embodiment, the pitch circle diameter PCDo of the 9 rows of the outer side tapered rollers is set to a larger diameter (PCDo> PCDi) than the pitch circle diameter PCDi of the 10 rows of the inner side tapered rollers, and the outer side The roller length Lo of the 9 rows of tapered rollers is set to be longer than the roller length Li of the 10 rows of tapered rollers on the inner side (Lo> Li). Further, the roller diameter do of the 9 rows of the outer side tapered rollers is set to a smaller diameter (di <do) than the roller diameter di of the 10 rows of the inner side tapered rollers. The number Zo is set to be larger than the number of rollers Zi of the inner side tapered roller 10 row (Zo> Zi). As a result, a wheel that is lighter and more compact, secures the basic load rating of the inner bearing row, and improves the rigidity and life of the bearing without increasing the outer diameter of the outer member 1. A bearing device can be provided.

  FIG. 2 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the above-described embodiment only in the configuration of the hub wheel, and other parts having the same parts or the same functions are denoted by the same reference numerals and detailed description thereof is omitted. .

  The wheel bearing device is for a driven wheel called a second generation, and includes a hub wheel 17 and a wheel bearing 18 fixed to the hub wheel 17. The hub wheel 17 integrally has a wheel mounting flange 5 at one end portion on the outer side, and a small-diameter step portion 17b extending in the axial direction from the wheel mounting flange 5 via a shoulder portion 17a is formed.

  The wheel bearing 18 is press-fitted into the small-diameter step portion 17b through a predetermined shimiro while being in contact with the shoulder portion 17a of the hub wheel 17, and is formed by plastically deforming the end portion of the small-diameter step portion 17b. It is fixed in the axial direction by the fastening portion 2d. The hub wheel 17 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is set to a range of 58 to 64 HRC by induction hardening from the shoulder portion 17a to the small diameter step portion 17b. It has been cured. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 5, and the fretting resistance of the small-diameter step portion 17 b serving as the fitting portion of the wheel bearing 18 is improved.

  The wheel bearing 18 integrally has a vehicle body mounting flange 1c to be attached to a knuckle (not shown) on the outer periphery, and an outer member 1 in which double row outer rolling surfaces 1a and 1b are formed on the inner periphery. And between the two inner races 19 and 3 formed on the outer periphery with inner rolling surfaces 19a and 3a facing the double-row outer rolling surfaces 1a and 1b, respectively, and both rolling surfaces 1a, 19a and 1b and 3a. Are provided with double-row tapered rollers 9 and 10 which are accommodated so as to be freely rollable via cages 7 and 8. Seals 20 and 12 are attached to the opening portion of the annular space formed between the outer member 1 and the two inner rings 19 and 3, leakage of grease sealed inside the bearing to the outside, and rainwater from the outside And dust are prevented from entering the bearing.

  The inner rolling surface 19 a of the inner ring 19 on the outer side is formed in a tapered shape that makes line contact with the tapered roller 9, as with the inner ring 3 on the inner side. And, the inner diameters of the two inner rings 19, 3 are set to the same size, and the back end type double row tapered roller bearing in which the small diameter side end surfaces 19d, 3d of the two inner rings 19, 3 are abutted in a butted state is constituted. ing. Thereby, the small-diameter stepped portion 17b can be integrally processed in a straight shape, the processing man-hours can be simplified, and the cost can be reduced. A large collar 19b for guiding the tapered roller 9 is formed on the large diameter side of the inner rolling surface 19a, and a small collar 19c for preventing the tapered roller 9 from falling off is formed on the small diameter side. The inner ring 19 is made of high carbon chrome steel such as SUJ2, and is hardened in the range of 58 to 64 HRC up to the core portion by quenching.

  Here, in this embodiment, as in the first embodiment described above, the pitch circle diameter PCDo of the nine rows of outer tapered rollers is larger than the pitch circle diameter PCDi of the ten rows of inner tapered rollers (PCDo>). PCDi), and the roller length Lo of the 9 rows of outer side tapered rollers is set to be longer than the roller length Li of the 10 rows of inner tapered rollers (Lo> Li). Further, the roller diameter do of the 9 rows of the outer side tapered rollers is set to a smaller diameter (di <do) than the roller diameter di of the 10 rows of the inner side tapered rollers. The number Zo is set to be larger than the number of rollers Zi of the inner side tapered roller 10 row (Zo> Zi). As a result, the weight and size can be reduced, the basic load rating of the inner bearing row can be secured, and the rigidity and life of the bearing can be improved without increasing the outer diameter of the outer member 1. it can.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a second or third generation structure constituted by double-row tapered roller bearings, regardless of whether for driving wheels or driven wheels.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1. Outer member 1a, 1b ... Outer rolling surface 1c ... Car body mounting flange 2, 17 ... Hub wheel 2a, 3a, 19a ... Inner rolling surface 2b, 17b ... Small diameter step 2c, 14, 17a ... Shoulder 2d ... Clamping part 2e, 15a ··· Serrations 2f, 3b, 19b ···· Large 2g, 3c, 19c ······ Small 3, 19 ······· Inner ring 4 ··· Inner member 5 ..... Wheel mounting flange 5a ..... Circular hole 5b ..... Seal land 6 ..... Hub bolt 7 , 8... Cage 9, 10... Tapered rollers 11, 12, 20.・ ・ ・ ・ ・ ・ Shaft 1 b ... Male thread 16 ... Fixing nut 18 ... Wheel bearing 50 ... Hub wheel 50a ...・ ・ ・ ・ Small diameter step 51 ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel bearing 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 52a ・ ・ ・ ・ ・ ・ ・ ・ Hub bolt 53 ・ ・ ・ ・..... caulking part 54 ..... outer members 54a, 54b ..... outer rolling surface 54c ..... car body mounting flanges 55, 56 ... ... Inner rings 55a, 56a ... Inner rolling surface 57 ... Outer side tapered rollers 58 ... Inner side tapered rollers 59, 60 ... ·················································································· Tapered roller diameter D1 ······························ Pitch circle diameter D2 of the outer side tapered roller ··············· Pitch circle diameter Li of the inner side tapered roller ... Inner side tapered roller length Lo ... Outer side tapered roller length N ... Knuckle PCDi ...・ Pitch circle diameter of the inner side tapered roller PCDo ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of the outer side tapered roller Zi ・ ・ ・ ・ ・ ・ ・ ・ Number of rollers of the inner side tapered roller Zo ・ ・ ・... Number of outer tapered rollers

Claims (4)

An outer member integrally having a vehicle body mounting flange to be attached to the knuckle on the outer periphery, and a double row outer rolling surface formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, a small diameter stepped portion formed on the outer periphery, and press-fitted into the small diameter stepped portion of the hub wheel, and the double row outer rolling on the outer periphery An inner member composed of at least one inner ring formed with an inner rolling surface facing the surface;
In the wheel bearing device including the inner member and a double row tapered roller row accommodated in a freely rolling manner between both rolling surfaces of the outer member,
The pitch circle diameter of the outer tapered roller row of the double row tapered roller rows is set to be larger than the pitch circle diameter of the inner tapered roller row, and the roller length of the outer tapered roller row is set to be larger. The roller length of the inner side tapered roller row is set longer than the roller length of the outer side tapered roller row, the roller diameter of the outer side tapered roller row is set smaller than the roller diameter of the inner side tapered roller row, and the outer A wheel bearing device, wherein the number of rollers in the side tapered roller row is set to be greater than the number of rollers in the inner side tapered roller row.   An outer side inner rolling surface is directly formed on the outer periphery of the hub wheel, and the small-diameter step portion extending in the axial direction from the inner rolling surface is formed. The wheel bearing device according to claim 1, wherein the inner ring is press-fitted.   The wheel bearing device according to claim 1, wherein two inner rings are press-fitted into the small-diameter step portion of the hub ring, and the inner diameters of these inner rings are set to the same size.   The wheel bearing device according to any one of claims 1 to 3, wherein the inner ring is fixed in an axial direction by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward.

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