JP2008223994A - Bearing for strut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a slide-contact surface of a sealing member into a totally smooth surface in a cap body of a bearing for a strut made of a polymeric material. <P>SOLUTION: In a movable type 48, the bearing for the strut turns the whole smooth each slide-contact surface formation parts 52, 53 for forming the slide-contact surfaces 31, 32 of each of the sealing member of the upper cap body 22 made of the polymeric material and at the same time forms each pawl body 36 on a skirt part 28 of the upper cap body 22 by each slide core 47 incorporated in a stationary type 44. Thereby, in the upper cap body 22, the bearing for the strut turns the whole smooth with the slide-contact surfaces 31, 32 of each of the sealing member with which the sealing members 24, 25 fastened to an inner ring 16 are brought into slide contact and at the same time is formed on the skirt part 28 of the upper cap body 22 in undercut-like fashion with the pawl body 36 which is engaged to a groove part 41 of a lower cap body 17. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a strut bearing used for a strut suspension of a vehicle.

  A strut suspension used for a front wheel of a vehicle (for example, an automobile) is a strut assembly that is mounted on a support member and supports a part of a vehicle body, and a shock absorber is built in a strut shaft. A coil spring that absorbs vibration and shock is wound. And the bearing for struts is interposed between the stabilizer support attached to the front-end | tip part of a strut axis | shaft, and the coil spring sheet | seat which supports a coil spring. As a strut bearing, for example, a technique disclosed in Patent Document 1 exists.

  When the above-described strut suspension is mounted on an automobile, it is necessary to make the thickness (bearing width) as small as possible in order to improve the compatibility. Moreover, it is desirable that it is lightweight. For this reason, a polymer material is used for members (for example, cap bodies) other than the bearing rings and rolling elements of the strut bearing. This cap body is usually manufactured by injection molding.

  In addition, a seal member is fixed to the raceway ring in order to seal the periphery of the rolling element. The seal member is made of a polymer material that is softer than the cap body, and seals the peripheral portion of the rolling element by being in sliding contact with the seal member sliding contact surface of the cap body.

  Here, when the assembled strut bearing is transported, it is desirable to prevent the pair of cap bodies from being separated. For this reason, while an engaging part is provided in the cap body of one side, the to-be-engaged part which engages the said engaging part may be provided in the cap body of the other side. In the case where the engaging portion is a claw body provided in an undercut shape in a skirt portion extended to the peripheral edge portion of the cap body on one side, the manufacturing method becomes a problem. For example, when a “collapsible core” manufactured by DMA Corporation of the United States is used, irregularities are formed on the sliding surface of the cap body sealing member, which may damage the cap body sealing member. As a result, the life of the strut bearing is shortened. The “collapsible core” described above is expensive.

The cap body after molding is released from the mold by being ejected by the ejector pins. The protrusions and protrusions of the ejector pins at this time cause irregularities, which may cause the same problem as described above.
JP 2003-28175 A

  In view of the above-described problems, an object of the present invention is to make the sliding surface of the seal member a smooth surface as a whole in a cap member of a strut bearing made of a polymer material.

Means for Solving the Problems and Effects of the Invention

The first invention for achieving the above object is as follows:
A plurality of rolling elements are interposed between first and second race rings that are annularly arranged opposite to each other, and a first shaft insertion hole through which a strut shaft is inserted, and the first race ring are attached. A first cap body having a first attachment surface; a second shaft insertion hole through which the strut shaft is inserted in the same axis as the first shaft insertion hole; and a second attachment to which the second race is attached. A strut bearing for use in a vehicle strut suspension, comprising a second cap body having a surface,
When one of the first and second bearing rings is a fixed-side bearing ring integrated with the vehicle body side support, and the other is a rotation-side bearing ring integrated with the upper end of the strut shaft, A sealing member made of a polymer material is fixed to the rotating side raceway,
Of the first and second cap bodies, the fixed-side cap body to which the fixed-side race ring is attached is formed of a polymer material harder than the seal member, and the tip end portion of the seal member is slidably contacted. A seal member sliding contact surface, and an engaging portion bulged and formed in an undercut shape on the inner peripheral surface or outer peripheral surface of the annular skirt portion extending from the peripheral portion along the axial direction. ,
The rotation-side cap body to which the rotation-side raceway is attached has an engaged portion that engages the engagement portion of the fixed-side cap body when fitted to the skirt portion of the fixed-side cap body. And
Further, in order to form the seal member slidable contact surface, the fixed-side cap body is provided with respect to one molding die disposed on the side opposite to the side on which the molding of the seal member slidable contact surface is planned. The molding surface for forming the seal member sliding contact surface is formed as a smooth surface over the entire surface, and the other molding die provided with the relief portion corresponding to the engagement portion is formed in the axial direction. Are moved relative to each other to close the mold, and in order to form the engaging portion in the skirt portion, a slide core provided in the one mold is advanced to be provided in the other mold. The molten polymer material is injected into the cavities formed in both molds in a state of entering the relief portion, thereby forming the sealing member sliding contact surface of the fixed-side cap body into a smooth surface over the entire surface. It is characterized by being made .

  In the bearing for struts according to the present invention, the sliding surface of the sealing member of the fixed cap body made of a polymer material is formed by the molding surface of the other molding die that is a smooth surface and the slide core. Is done. For this reason, the seal member slidable contact surface is formed as a smooth surface over the whole, and the track is attached to the rotating side cap body that is slidably contacted with the seal member slidable contact surface while rotating about the axis of the fixed side cap body. The seal member fixed to the ring is less likely to be damaged. As a result, the life of the bearing can be extended.

  Furthermore, the fixed-side cap body has an ejector pin attached to one of the molds when the molds of the two molds are opened, with respect to the fixed-side cap molded body formed by solidification of the molten polymer material. Thus, the slide core can be released from the molding die by protruding away from the sliding contact surface of the seal member that is completely released when viewed from the axial direction as the slide core moves backward.

  In this invention, since the protrusion trace of the ejector pin is not formed on the seal member sliding contact surface of the fixed-side cap body, the surface can be more surely made smooth.

  Moreover, it is desirable that the seal member is fixed over the entire circumference of the inner peripheral surface and the outer peripheral surface of the rotating raceway in a form in which the plurality of rolling elements are sandwiched.

  Thereby, leakage of the lubricant supplied to the sliding surface of the rolling element is prevented, and occurrence of problems such as seizure is suppressed.

Specifically, the engagement portion is a plurality of claws provided at a predetermined angle in the circumferential direction on the skirt portion of the fixed-side cap body,
The engaged portion may be a groove provided on the outer peripheral surface of the rotation-side cap body over the entire circumference so that the claw body can be engaged.

  Thereby, operation which unites both is also easy, without impairing the advantage that it becomes difficult to isolate | separate a fixed side cap body and a rotation side cap body.

  And the window part for letting the said slide core pass is formed in the skirt part of the said fixed side cap body, and the rigidity of the skirt part in the said window part is reinforced in the lower end peripheral part of the said skirt part A reinforcing member can also be provided.

  Since the rigidity of the skirt portion is reinforced, even if the window portion is provided, the skirt portion is hardly damaged.

And 2nd invention is a manufacturing method of the bearing for struts, Comprising:
On the inner peripheral surface of the skirt portion of the fixed-side cap body, an engaging portion that is engaged with the engaged portion of the rotating-side cap body is bulged and formed in an undercut shape,
A molding surface for forming the seal member slidable contact surface with respect to one molding die arranged on the side opposite to the side on which the molding of the seal member slidable contact surface is scheduled on the fixed side cap body, A mold closing step of closing the mold by relatively moving along the axial direction the other mold that is formed on a smooth surface and provided with a relief portion corresponding to the engaging portion; ,
In order to form the engaging portion in the skirt portion of the fixed-side cap body, a slide core provided in the one mold is formed in a direction perpendicular to the axial direction from the outside of the skirt portion of the fixed-side cap body. And a slide core entering step in which the slide core is advanced along the second mold and entered into the escape portion provided in the other mold,
An injection step of injecting a molten polymer material into a cavity formed in both molds in a closed state;
A mold opening step of retracting the slide core to open both molds; and
The ejector pin attached to the other mold is released from the entire surface as viewed from the axial direction as the slide core moves backward with respect to the fixed-cap molded body formed by solidifying the molten polymer material. A mold release step of releasing the fixed-side cap molded body from the other mold by protruding to avoid the seal member sliding contact surface;
It is characterized by being molded.

  Since the configuration of the molding die is simpler than before, the molding die is inexpensive and the strut bearing is easily manufactured.

  Examples of the present invention will be described. 1 is a perspective view of a strut suspension 100 for an automobile, FIG. 2 is an enlarged cross-sectional view of a portion P in FIG. 1, FIG. 3 is a front cross-sectional view of a strut bearing 200 of this embodiment, and FIG. FIG. 5 is a bottom view of the upper cap body 22 in a state in which each member is separated.

  As shown in FIG. 1, a strut suspension 100 for a vehicle includes a strut assembly mounted on a support member 1 to support a part of a vehicle body, and a strut assembly 2 in which a shock absorber 3 is internally mounted. A coil spring 4 that absorbs vibration and shock is wound. As shown in FIG. 2, a strut bearing 101 is interposed between a stabilizer support 5 attached to the distal end portion of the strut shaft 2 and a coil spring seat 6 that supports the coil spring 4. The strut suspension 100 has a role of supporting the entire vehicle body in a floating manner with respect to the axle or the like. Around the support member 1, an axle 7, a hub 8 fixed to the axle 7 and fitted with wheels (not shown), a brake disc 9 fixed to the hub 8, and a pressure contact with the brake disc 9 by hydraulic pressure. A caliper body 11 that accommodates a pad (not shown) is disposed.

  More specifically, as shown in FIG. 2, a coil spring seat 6 that holds the spring seat 12 of the coil spring 4 and a thrust that is held at the upper end of the strut shaft 2 are provided on the upper part of the strut suspension 100. A ball bearing (strut bearing 200), a housing 13 (vehicle body side support portion) that holds the strut bearing 200, a stabilizer support 5 that holds these so as to surround them, and the like are provided. The stabilizer support 5 includes a support main body portion 14 made of an elastic material and an outer cylinder portion 15 attached so as to cover the outer peripheral surface thereof, and is fixed to the housing 13.

  A coil spring seat 6 is fixed to the upper portion of the strut shaft 2, and a lower cap body 18 (rotation side cap body) that holds the inner ring 16 (rotation side raceway) of the strut bearing 200 on the coil spring sheet 6. It is fixed. A ring member 19 is fixed to the upper end portion of the strut shaft 2 by a nut 18. The ring member 18 is rotatable within the support main body 14. On the other hand, the upper cap body 22 that holds the outer ring 21 of the strut bearing 200 is fitted and fixed to the housing 13. The housing 13 is fixed to a vehicle body (not shown) via a stabilizer support 5.

  The strut bearing 200 of this embodiment will be described. As shown in FIG. 3, the strut bearing 200 of the present embodiment has an upper and lower cap bodies (lower cap body 17 and upper cap body 22) made of an annular, hard polymer material (for example, polyamide), and The upper and lower race rings (inner ring 16 and outer ring 21), which are also made of a metal material, and a plurality of balls 23 are provided. Seal members 24 and 25 made of a polymer material (for example, rubber material) softer than the cap bodies 17 and 21 are integrally fixed to the outer peripheral edge and the inner peripheral edge of the inner ring 16.

  First, the upper cap body 22 will be described. As shown in FIGS. 3 to 5, the upper cap body 22 includes an upper cap body main body portion 27 provided with a shaft insertion hole 26 for allowing the strut shaft 2 to pass through the shaft center portion (the portion of the axis C <b> 1). And a short cylindrical skirt portion 28 extending downward from the peripheral edge of the upper cap body main body 27. The bottom surface portion of the upper cap body 27 has a semicircular cross section, and an outer ring mounting groove 29 for holding the outer ring 21 and a seal member sliding contact for bringing the seal members 24 and 25 of the inner ring 16 into contact with each other. The surfaces 31 and 32 are formed over the entire circumference.

  The shaft insertion hole 26 provided in the upper cap body main body 27 has a stepped shape, and the stepped portion 26a is used for releasing from the mold (described later) when the upper cap body 22 is injection-molded. A contact mark (concave part 34) of the ejector pin 33 (see FIG. 6) is provided. In the case of the upper cap body 22 of the present embodiment, eight concave portions 34 are provided at equal angles in the circumferential direction.

  The skirt portion 28 of the upper cap body 22 is provided with a plurality of (eight in the case of this embodiment, equiangular in the circumferential direction) window portions 35, A claw body 36 that projects toward the axis of the upper cap body 22 is provided. Each claw body 36 slightly protrudes toward the axial center from the inner peripheral surface of the skirt portion 28 and is formed in an undercut shape. And the lower surface of each nail | claw body 36 becomes an inclined surface which becomes taper (namely, it becomes thin as it approaches a lower end surface). In addition, each protrusion 37 extends downward from a portion of the skirt portion 28 immediately below the portion where each window 35 is formed. By providing each window part 35 in the skirt part 28, the rigidity of the lower end part of each window part 35 in the skirt part 28 will fall. However, the rigidity of the portion where each window 35 is formed is reinforced by each projection 37.

  Next, the lower cap body 17 will be described. As shown in FIGS. 3 and 4, similarly to the upper cap body 22 described above, the shaft insertion for inserting the strut shaft 2 into the axial center portion (the portion of the axis C <b> 2) of the lower cap body 17. A hole 38 is provided. The outer diameter of the lower cap body 17 is slightly smaller than the inner diameter of the skirt portion 28 of the upper cap body 22. Further, an inner ring mounting groove 39 for holding the inner ring 16 is formed on the upper surface portion of the lower cap body 17 over the entire circumference. And the groove part 41 is provided in the outer peripheral part of the lower side cap body 17 over the perimeter. When the lower cap body 17 and the upper cap body 22 are assembled, the skirt portion 28 of the upper cap body 22 is fitted to the outer peripheral portion of the lower cap body 17. For this reason, the axis C2 of the lower cap body 17 in the assembled state coincides with the axis C1 of the upper cap body 22. Then, each claw body 36 of the upper cap body 22 is engaged with the groove portion 41 of the lower cap body 17. Accordingly, the cap bodies 17 and 22 are prevented from coming off, and the members of the strut bearing 200 are prevented from being separated during the conveyance.

  Next, the inner ring 16 will be described. As shown in FIGS. 3 and 4, an inner ring raceway surface 16 a having a substantially semicircular cross section corresponding to the outer diameter of the ball 23 is provided on the upper surface of the inner ring 16. The seal member mounting portions 42 and 43 are extended from the inner ring raceway surface 16a of the inner ring 16 to the outer side and the inner side in the radial direction. Seal members 24 and 25 are fixed to the respective seal member mounting portions 42 and 43 over the entire circumference.

  Next, the outer ring 21 will be described. As shown in FIGS. 3 and 4, similarly to the inner ring 16 described above, an outer ring raceway surface 21 a having a substantially semicircular cross section corresponding to the outer diameter of the ball 23 is provided on the bottom surface of the outer ring 21. The outer ring 21 is held in the outer ring mounting groove 29 of the upper cap body 22, and the inner ring 16 is held in the inner ring mounting groove 39 of the lower cap body 17, and a predetermined number is provided between the raceway surfaces 16 a and 21 a. Ball 23 is arranged.

  Next, a manufacturing method (injection molding method) of the upper cap body 22 will be described. As shown in FIG. 6, the fixed die 44 of the forming die has a spool bush 45 attached to the portion of the axis 44 a and a cavity forming portion 46 corresponding to the outer peripheral surface of the upper cap body 22. Is provided. In the cavity forming portion 46, a slide core 47 is attached to a portion where each window portion 35 provided in the skirt portion 28 of the upper cap body 22 is formed. Each slide core 47 is advanced beyond the peripheral surface of the cavity forming portion 46 of the fixed mold 44 by means (not shown) (for example, a hydraulic cylinder).

  The movable die 48 of the forming die is provided with a short columnar protrusion 49 for forming the shaft insertion hole 26 of the upper cap body 22. The front end surface 49a of the protrusion 49 is formed as a smooth surface over the entire surface (in other words, the front end surface 49a of the protrusion has no irregularities). Further, a protrusion 51 having a semicircular cross section for forming the outer ring attachment groove 29 is provided in an annular shape around the protrusion 49. Each ejector pin 33 is attached between the protrusion 49 and the protrusion 51. In addition, on the inner side and the outer side of the protrusion 51, sliding surface forming portions 52 and 53 for forming the sealing member sliding surfaces 31 and 32 are provided. Each of the slidable contact surface forming portions 52 and 53 is formed on a smooth surface throughout. Further, on the outer side of the ridge 51, a relief portion 54 for allowing each slide core 47 to enter and a projection portion forming hole 55 for forming each projection portion 37 in the upper cap body 22 are provided. ing.

  As shown in FIGS. 7 and 8, the protrusion 49 and the protrusion 51 of the movable die 48 enter the cavity forming portion 46 of the fixed die 44 and are closed (die closing step). In this state, a cavity 56 is formed in a space formed by the fixed mold 44 and the movable mold 48. Then, each slide core 47 is advanced (slide core entering step). Thereby, the window part 35 and the undercut nail | claw body 36 are shape | molded by the skirt part 28. FIG. As shown in FIG. 8, each slide core 47 and the movable die 48 do not interfere with each other because the tip portion of each slide core 47 stops immediately before the escape portion 54 of the corresponding movable die 48. The molten resin A is injected from the nozzle 55 of the injection molding machine into the cavity 54 of the fixed mold 44 through the spool bush 45, the runner 58, and the gate 59, and the fixed mold 44 and the movable mold 48 are clamped (injection process). ). In FIG. 8, the slide core 47 in the retracted state (the state accommodated in the fixed mold 44) is indicated by a two-dot chain line.

  After a predetermined time has elapsed, the mold clamping force is released, and after each slide core 47 is retracted, the movable mold 48 is separated from the fixed mold 44 (mold opening process). As a result, the seal member sliding contact surfaces 31, 32 of the upper cap molded body 61 (referred to the runner 58 and the spool 62 attached to the upper cap body 22) are fully released as viewed from the direction of the axis C1. . The upper cap molded body 61 is held by the protrusions 49 and the protrusions 51 of the movable mold 48 and is separated from the movable mold 48 integrally. Then, each ejector pin 33 disposed on the movable mold 48 is protruded, and the upper cap molded body 58 is protruded to be released from the movable mold 48 (release process). Each ejector pin 33 protrudes away from the seal member sliding contact surfaces 31 and 32 of the upper cap molded body 61. For this reason, the protrusion mark (recess 34) of the ejector pin 33 is not formed on each of the seal member sliding contact surfaces 31, 32. The runner 58 is cut out from the upper cap molded body 61 to form the upper cap body 22.

  The lower cap body 17 is molded in substantially the same manner as the upper cap body 22 described above. In the case of the strut bearing 100 of the present embodiment, since the seal members 24 and 25 are not slidably contacted with the lower cap body 17, there is no restriction on the position where each ejector pin 33 protrudes.

  The operation of the strut bearing 200 of this embodiment will be described. In the strut bearing 200 of this embodiment, when the upper and lower cap bodies 17 and 22 are relatively fitted, the claw body 36 of the upper cap body 22 is engaged with the groove 41 of the lower cap body 17. The At this time, since the lower surface of each claw body 36 is inclined so as to be tapered, the upper and lower cap bodies 17 and 22 can be easily engaged. This makes it difficult to separate the upper and lower cap bodies 17 and 22 during conveyance.

  Then, the strut bearing 200 of this embodiment is assembled to the strut suspension 100 of the vehicle. The impact from the road surface acting on the traveling vehicle is absorbed by the expansion and contraction of the shock absorber 3 and the coil spring 4. The loads in the thrust direction and the radial direction at that time are loaded by the thrust bearing function and the radial bearing function of the strut bearing 200. When the strut bearing 200 receives a radial load and the inner ring 16 and the outer ring 21 are relatively rotated, the sealing members 24 and 25 fixed to the inner and outer peripheral surfaces of the inner ring 16 and the upper side The seal member sliding contact surfaces 31 and 32 of the cap body 22 rub against each other. Here, since the seal members 24 and 25 are made of a polymer material that is softer than the upper cap body portion 27 of the upper cap body 22, if the seal member sliding contact surfaces 31 and 32 have irregularities, the seal members 24 and 25 may be damaged.

  However, in the case of the strut bearing 200 of the present embodiment, the upper cap body 22 is manufactured through the above-described steps. For this reason, each sealing member sliding contact surface 31 and 32 is shape | molded by the smooth surface over the whole. Thereby, damage to each sealing member 24 and 25 is prevented, and the strut bearing 200 can be used over a long period of time.

  Furthermore, the molds (fixed mold 44 and movable mold 48) used in the manufacturing method of the strut bearing 200 of the present embodiment are less expensive than conventional molds (for example, “collapsible core”).

  The upper cap body 22 of the strut bearing 200 of the present embodiment is a case where each claw body 36 is provided in an undercut shape on the inner peripheral surface of the skirt portion 28. However, the case where each nail | claw body 36 was provided in the undercut shape on the outer peripheral surface of the skirt part 28 may be sufficient. Further, each claw body 36 may be provided in the lower cap body 17, and the upper cap body 22 may be provided with a groove portion 41 for engaging each claw body 36.

1 is a perspective view of a strut suspension 100 for an automobile. It is an expanded sectional view of the P section of FIG. It is front sectional drawing of the bearing 200 for struts of a present Example. It is a front view in the state where each member of bearing 200 for struts was separated. 4 is a bottom view of the upper cap body 22. FIG. It is front sectional drawing of the state which spaced apart the fixed mold | type 44 and the movable mold | type 48. FIG. FIG. 5 is an operation explanatory diagram in a state where a fixed mold 44 and a movable mold 48 are closed and a molten resin A is injected. It is the XX sectional view taken on the line of FIG. It is action | operation explanatory drawing of the state which opens the fixed mold | type 44 and the movable mold | type 48, and releases the upper side cap body 22. FIG.

Explanation of symbols

100: Strut suspension
200: Strut bearing
2: Strut shaft
16: Inner ring (first track ring, rotation side track ring)
17: Lower cap body (first cap body)
21: Outer ring (second raceway, fixed-side raceway)
22: Upper cap body (second cap body)
23: Ball (rolling element)
24, 25: Seal member
26: shaft insertion hole (second shaft insertion hole)
28: Skirt
29: Outer ring mounting groove (second mounting surface)
31, 32: sliding surface of the seal member
36: Claw body (engagement part)
38: Shaft insertion hole (first shaft insertion hole)
39: Inner ring mounting groove (first mounting surface)
41: Groove (engaged part)
44: Fixed mold (one mold)
48: Movable mold (the other mold)
56: Cavity
A: Molten resin (molten polymer material)
C1, C2: Axis

Claims (1)

A plurality of rolling elements are interposed between first and second race rings that are annularly arranged opposite to each other, and a first shaft insertion hole through which a strut shaft is inserted, and the first race ring are attached. A first cap body having a first attachment surface; a second shaft insertion hole through which the strut shaft is inserted in the same axis as the first shaft insertion hole; and a second attachment to which the second race is attached. A strut bearing for use in a vehicle strut suspension, comprising a second cap body having a surface,
When one of the first and second bearing rings is a fixed-side bearing ring integrated with the vehicle body side support, and the other is a rotation-side bearing ring integrated with the upper end of the strut shaft, A sealing member made of a polymer material is fixed to the rotating side raceway,
Of the first and second cap bodies, the fixed-side cap body to which the fixed-side race ring is attached is formed of a polymer material harder than the seal member, and the tip end portion of the seal member is slidably contacted. A seal member sliding contact surface, and an engaging portion bulged and formed in an undercut shape on the inner peripheral surface or outer peripheral surface of the annular skirt portion extending from the peripheral portion along the axial direction. ,
The rotation-side cap body to which the rotation-side raceway is attached has an engaged portion that engages the engagement portion of the fixed-side cap body when fitted to the skirt portion of the fixed-side cap body. And
Further, in order to form the seal member slidable contact surface, the fixed-side cap body is provided with respect to one molding die disposed on the side opposite to the side on which the molding of the seal member slidable contact surface is planned. The molding surface for forming the seal member sliding contact surface is formed as a smooth surface over the entire surface, and the other molding die provided with the relief portion corresponding to the engagement portion is formed in the axial direction. Are moved relative to each other to close the mold, and in order to form the engaging portion in the skirt portion, a slide core provided in the one mold is advanced to be provided in the other mold. The molten polymer material is injected into the cavities formed in both molds in a state of entering the relief portion, thereby forming the sealing member sliding contact surface of the fixed-side cap body into a smooth surface over the entire surface. The feature is that Rats bearing.

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