JP5234522B2 - Rotation detecting device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a rotation detection device used as a wheel speed sensor and a manufacturing method thereof.

  Conventionally, as a rotation detection device that detects the rotation speed of a wheel of an automobile or the like, a magnetic sensor such as a Hall IC detects a situation in which a magnetic field generated by a permanent magnet changes due to rotation of a rotating body attached to an axle such as a metal rotor. The type to be used is widely used.

  By the way, such a rotation detection device is mounted on a wheel bearing portion of an automobile and is exposed to dust, vibration, etc. from the road surface. Therefore, a magnetic sensor, a permanent magnet, a lead wire, etc. are accommodated inside and made of synthetic resin. It has been proposed to cover the case by molding. For example, it is as described in Patent Document 1 (Japanese Patent Laid-Open No. 2001-141738). In this way, the magnetic sensor or the like is housed in a separate case and the case has a sufficient hermeticity and fixing strength compared to a structure in which the opening of the case is sealed. Can fit inside. Thereby, the malfunction that a magnetic sensor etc. are exposed to dust, a vibration, etc. and detection accuracy falls can be avoided.

  However, in such a rotation detection device, since the magnetic sensor is housed in a sealed state in a synthetic resin case, the case is interposed between the detection surface of the magnetic sensor and the metal rotor. The detection distance is shortened by an amount corresponding to the amount of attenuation of the magnetic force, and there is a limit to improvement in detection accuracy.

  In addition, when the case is molded by positioning the magnetic sensor with respect to the case mold, the injection pressure of the synthetic resin is applied to the magnetic sensor, and the magnetic sensor may be displaced or distorted. It was. Such misalignment or distortion of the magnetic sensor causes the generation of erroneous pulses at the time of detection, and there is also a problem that it is difficult to sufficiently secure the detection accuracy of the rotation detection device.

JP 2001-141738 A

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is to provide a rotation detection device having a novel structure capable of improving the detection distance and accuracy, and a method for manufacturing the same. is there.

According to a first aspect of the present invention relating to the rotation detection device, in the rotation detection device in which the case made of synthetic resin is molded with the magnetic sensor and the permanent magnet embedded, the detection side surface and the magnet side surface of the magnetic sensor are mutually connected. The front and back surfaces are parallel planes, the detection side surface of the magnetic sensor is exposed on the surface of the case to form a detection surface facing the rotor, and the magnetic side surface of the magnetic sensor is While the permanent magnet is directly superposed, an engagement portion is provided on the outer peripheral surface of the portion embedded in the case of the magnetic sensor so as to be engaged with the case, and the case of the magnetic sensor. with exit is prevented by the engagement portion from, the magnetic sensor includes a pair of lead portions which are a flat plate shape is formed integrally The detection side surface of the magnetic sensor and the pair of lead portions extend in a parallel state, while the case is formed on the surface of the permanent magnet opposite to the overlapping surface of the magnetic sensor. A first pin hole for exposing the permanent magnet, and a second pin hole for exposing the pair of lead parts formed across the pair of lead parts at a position away from the magnetic sensor. And is provided .

  According to the first aspect, by exposing one surface (detection side surface) of the magnetic sensor to the surface of the case, the case interposed between the rotor and the rotor can be eliminated. This makes it possible to extend the detection distance when used as a rotation detection device.

  In addition, since the permanent magnet is directly superimposed on the other surface (magnet side surface) of the magnetic sensor, there is no gap between them (being able to overlap each other), and a stronger magnetic force can be generated. It can be transmitted to the sensor. Thereby, the detection accuracy of the rotor by the magnetic sensor is improved.

  Furthermore, the convex or concave engaged corresponding to the concave or convex at the time of molding the case can be integrally formed in the case by simply providing the concave or convex on the outer peripheral surface of the embedded portion of the magnetic sensor in the case. Thereby, the uneven | corrugated engagement which fixes a magnetic sensor firmly with respect to a case is implement | achieved. Therefore, the detection side surface of the magnetic sensor can be exposed to the outside with a sufficiently large area while preventing the magnetic sensor from coming out of the case.

According to a first aspect of the present invention relating to a method of manufacturing a rotation detector, a magnetic sensor in which a detection side surface and a magnet side surface are formed in a plane parallel to each other and a pair of flat lead portions are integrally formed. a plate-like component formed, to prepare a permanent magnet overlapping surfaces of the planar shape is superimposed on the magnet side is provided in the magnetic sensor, the bottom surface of the split mold constituting the mold of the case On the other hand, the detection side surface of the magnetic sensor is directly overlapped to set the pair of lead portions so as to extend along the bottom surface of the split mold, and the permanent magnet side surface of the magnetic sensor is permanently attached to the magnet side surface. The overlapping surfaces of the magnets are directly overlapped and set, and further, elastically pressed against the surface of the permanent magnet opposite to the overlapping surface to the magnetic sensor in the mold for molding the case Using the contact urging pins, Rutotomoni pressed against the direction superposing the permanent magnet relative to the magnetic sensor, the pressing pin is brought into contact so as to straddle the pair of lead portions at a position off the magnetic sensor Then, the magnetic sensor and the permanent magnet are embedded by filling the molding die of the case with a synthetic resin material in a state where the pair of lead portions are pressed against the bottom surface of the split mold by the pressing pin. The case made of synthetic resin to be accommodated in a state is molded.

  According to the first aspect of the method of manufacturing the rotation detecting device, the magnetic sensor is positioned at a predetermined position of the molding cavity with the molding die and the permanent magnet sandwiched between each other, and the case is molded. Therefore, it is possible to prevent displacement and distortion of the magnetic sensor due to the resin filling pressure. Thereby, generation | occurrence | production of the false pulse by the distortion | strain etc. of a magnetic sensor can be prevented.

In addition, since the magnetic sensor and the permanent magnet are elastically pressed and positioned, problems such as breaking of the permanent magnet during mold clamping can be prevented.
Furthermore, according to the first aspect of the method for manufacturing the rotation detection device, the plate-like component can be pressed and held by the pressing pin at the portion where the magnetic sensor is removed, so that an excessive pressing force is not applied to the magnetic sensor. It can be firmly positioned and held in the mold. Therefore, it is possible to effectively prevent the magnetic sensor from being displaced when the case molding die is filled with the synthetic resin material.

  According to a second aspect of the present invention relating to a method of manufacturing a rotation detecting device, in the first aspect, at least one concave or convex engaging portion is provided on the outer peripheral surface of the magnetic sensor. In the molding of the case, a convex portion or a concave portion corresponding to the concave or convex engaging portion of the magnetic sensor is integrally formed in the case so as to prevent the magnetic sensor from coming out of the case. It is a thing.

  According to the second aspect of the method for manufacturing the rotation detecting device, the concave-convex engagement for firmly fixing the magnetic sensor to the case can be easily realized.

  According to a third aspect of the present invention relating to a method of manufacturing a rotation detecting device, in the first or second aspect, as the permanent magnet, an outer peripheral side from the magnetic sensor in an overlapped state with the magnetic sensor. In the direction perpendicular to the direction in which the permanent magnet is superposed on the magnetic sensor by engaging the portion of the permanent magnet that protrudes from the magnetic sensor to the outer peripheral side. The case is molded by using a plurality of positioning projections that project from the bottom surface of the split mold and positioning the permanent magnet on the overlapping surface with respect to the magnetic sensor by using the positioning projections. It is a thing.

  According to the third aspect of the method for manufacturing the rotation detection device, when the synthetic resin material is filled in the mold for molding the case, the permanent magnet is superimposed on the magnetic sensor and is orthogonal to the overlapping direction. It is possible to prevent displacement in the direction.

  According to the present invention, the detection side surface of the magnetic sensor is exposed to the outside of the case, and the permanent magnet is directly superimposed on the magnet side surface of the magnetic sensor, so that the detection distance and the detection accuracy can be improved. .

The perspective view which shows the rotation detection apparatus as one Embodiment of this invention. II-II sectional drawing in FIG. FIG. 3 is a longitudinal sectional view in a state in which a magnetic sensor and a permanent magnet are set on a molding die of the rotation detecting device shown in FIG. 1, and is a sectional view in the III-III direction in FIG. 4. The top view which shows the positional relationship of a lower mold | type, an abutting biasing pin, and a pressing pin in the state which set the magnetic sensor and the permanent magnet in the lower mold | type which comprises the shaping | molding die shown in FIG. The perspective view which shows the positional relationship of the lower mold | type shown in FIG. 4, an abutting biasing pin, and a pressing pin.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show a rotation detection device 10 as an embodiment of the present invention. The rotation detection device 10 has a structure in which a magnetic sensor 12 and a permanent magnet 14 are embedded in a case 16.

  More specifically, the magnetic sensor 12 is composed of a rotation detection element such as a Hall IC, and has a thick rectangular plate shape as a whole. In the magnetic sensor 12, a detection side surface 18 facing a metal rotor as a rotor (not shown) and a magnet side surface 20 positioned on the back side and overlapped with the permanent magnet 14 are parallel to each other.

  On the outer peripheral surface 22 of the magnetic sensor 12, a convex engagement portion 24 that protrudes outward in a direction orthogonal to the thickness direction is provided. The engaging portion 24 has a substantially constant rectangular cross-sectional shape and continuously extends in the circumferential direction except for the position where the lead portion 28 described later is disposed.

  In addition, the engaging part does not need to be convex, may be concave, and may employ both convex and concave. Further, the engaging portions do not need to continuously extend in the circumferential direction of the outer peripheral surface 22, and for example, an appropriate number may be provided for each side surface 26 constituting the outer peripheral surface 22. Of course, there may be a side face 26 on which no engaging portion is provided.

  On one of the side surfaces 26 constituting the outer peripheral surface 22 of the magnetic sensor 12, a pair of lead portions 28, 28 project from the same height position as the engaging portion 24. Each of the pair of lead portions 28 and 28 has a rectangular plate shape and extends outward from the side surface 26 in a state parallel to the detection side surface 18. Thus, the magnetic sensor 12 in which the pair of lead portions 28 and 28 are integrally provided is a plate-like component 29 as a whole.

  A capacitor 30 is connected between the pair of lead portions 28 and 28, and signal processing such as noise removal is performed on the detection signal output from the magnetic sensor 12.

  An input electric wire 34a and an output electric wire 34b of the external conducting wire 32 are connected to the extending end side of each lead portion 28 by solder. The external conducting wire 32 is configured such that an input electric wire 34a and an output electric wire 34b having a structure in which a copper wire is covered with a synthetic resin coating film are bundled together and accommodated in a synthetic resin cover.

  On the other hand, the permanent magnet 14 has a thick rectangular block shape as a whole, and its planar shape is larger than the planar shape of the magnetic sensor 12. In the permanent magnet 14, the overlapping surface 36 that is superimposed on the magnet side surface 20 of the magnetic sensor 12 and the pressing surface 38 that is positioned on the back side of the overlapping surface 36 are parallel to each other.

  Such a permanent magnet 14 has its overlapping surface 36 directly overlapped with the magnet side surface 20 of the magnetic sensor 12. At that time, the outer center of the permanent magnet 14 and the outer center of the magnetic sensor 12 are located on a single straight line extending in the overlapping direction of the permanent magnet 14 and the magnetic sensor 12, The magnet 14 protrudes from the magnetic sensor 12 to the outer peripheral side.

  The rotation sensor 10 is formed by embedding the magnetic sensor 12 and the permanent magnet 14 superimposed in this manner in a case 16 made of synthetic resin. At that time, only the detection side surface 18 of the magnetic sensor 12 is exposed to the surface 40 of the case 16, and the detection surface that is opposed to the metal rotor is constituted by the detection side surface 18.

  Further, a convex engaging portion 24 protruding from the outer peripheral surface 22 of the magnetic sensor 12 is embedded in the case 16. In other words, the convex engaging portion 24 provided in the magnetic sensor 12 is fitted into the concave portion 42 formed in the surface of the case 16 that is overlapped with the outer peripheral surface 22 of the magnetic sensor 12. It has become. This prevents the magnetic sensor 12 from coming out of the case 16.

  Then, the manufacturing method of such a rotation detection apparatus 10 is demonstrated based on FIGS. First, the magnetic sensor 12 and the permanent magnet 14 prepared in advance are set in the molding die 44 of the case 16.

  Specifically, the detection side surface 18 of the magnetic sensor 12 is set directly on the bottom surface 50 of one of the two split dies 46 and 48 (hereinafter referred to as the lower die 46) constituting the molding die 44. To do. Thereafter, the overlapping surface 36 of the permanent magnet 14 is directly overlapped and set on the magnet side surface 20 of the magnetic sensor 12.

  At that time, the portion of the permanent magnet 14 that protrudes from the magnetic sensor 12 to the outer peripheral side is engaged with four positioning protrusions 52 that protrude from the bottom surface 50 of the lower mold 46. Each of the four positioning projections 52 extends vertically from the bottom surface 50 of the lower mold 46 with a substantially constant L-shaped cross section.

  Such positioning protrusions 52 are located outside the corners 54 of the permanent magnet 14 and are bent along the corners 54. Thereby, the corner | angular part 54 and the positioning protrusion 52 of the permanent magnet 14 are engaging. As a result, the permanent magnet 14 is positioned in a direction orthogonal to the direction of superimposition on the magnetic sensor 12 while being superimposed on the magnetic sensor 12.

  The pair of lead portions 28, 28 provided integrally with the magnetic sensor 12 are respectively placed on the projecting tip surfaces of the support projections 56 projecting from the bottom surface 50 of the lower mold 46. It extends along the bottom surface 50. Further, the capacitor 30 is located in a recess 58 formed in the bottom surface 50 of the lower mold 46.

  As described above, the other divided mold 48 (hereinafter referred to as the upper mold 48) is overlapped with the lower mold 46 on which the magnetic sensor 12 and the permanent magnet 14 are set, and the mold is clamped. Thereby, the magnetic sensor 12 and the permanent magnet 14 are set in the molding die 44.

  At that time, the contact urging pin 60 assembled to the upper die 48 is elastically pressed against the pressing surface 38 of the permanent magnet 14. The contact urging pin 60 as a whole has a circular cross section and has a rod shape that extends straight in the axial direction, and one axial direction is closer to the other side than the annular contact surface 62 formed in the axially intermediate portion. The contact shaft portion 64 has a small diameter.

  In addition, a positioning protrusion 66 that protrudes outward in the axial direction is provided at the central portion of the other end surface in the axial direction of the contact urging pin 60. One end of the coil spring 68 in the axial direction is arranged on the positioning protrusion 66.

  Such a contact urging pin 60 is formed in a receiving hole 70 formed so as to extend in the overlapping direction with the lower die 46 in the upper die 48 in a state where the contact shaft portion 64 is located on the lower die 46 side. Contained. A step surface 72 that can be engaged with the contact surface 62 of the contact urging pin 60 is formed on the inner peripheral surface of the accommodation hole 70, and the engagement action between the contact surface 62 and the step surface 72 is formed. This prevents the contact urging pin 60 from falling off the upper mold 48.

  Further, the opening portion of the accommodation hole 70 opposite to the lower mold 46 side is covered with a base plate 74 that is superimposed on the upper mold 48. Thus, the coil spring 68 is compressed between the other axial end surface of the contact biasing pin 60 and the base plate 74 in a state where the contact surface 62 and the stepped surface 72 are engaged. As a result, the urging force in the direction of projecting toward the lower mold 46 is constantly applied to the contact urging pin 60.

  As described above, when the upper die 48 and the lower die 46 are clamped, the abutting urging pin 60 accommodated in the accommodating hole 70 has the tip end surface of the abutting shaft portion 64 of the pressing surface 38 of the permanent magnet 14. It is pressed to the approximate center. At that time, the contact urging pin 60 is retracted into the accommodation hole 70 against the urging force of the coil spring 68. As a result, the permanent magnet 14 is pressed against the magnetic sensor 12 in a state where the contact biasing pin 60 is elastically pressed against the pressing surface 38 of the permanent magnet 14. As a result, the magnetic sensor 12 and the permanent magnet 14 are positioned in their overlapping direction.

  Further, in the clamped state of the upper mold 48 and the lower mold 46, the two pressing pins 76, 76 assembled to the upper mold 48 are pressed against the pair of lead portions 28, 28. Each of the two pressing pins 76 and 76 has a rod shape extending straight in the axial direction with a constant cross-sectional shape as a whole, and a contact surface formed so as to spread in the direction perpendicular to the axis at the intermediate portion in the axial direction. An abutting shaft portion 80 having a cross section slightly smaller in the axial direction than 78 on the one side in the axial direction is formed.

  Such a pressing pin 76 is accommodated and disposed in the accommodation hole 82 formed so as to extend in the overlapping direction with the lower die 46 in the upper die 48 in a state where the contact shaft portion 80 is positioned on the lower die 46 side. ing. A stepped surface 84 that can be engaged with the contact surface 78 of the pressing pin 76 is formed on the inner peripheral surface of the accommodation hole 82, and the pressing operation is performed by the engagement of the contact surface 78 and the stepped surface 84. The pin 76 is prevented from falling off from the upper mold 48. In addition, the opening portion of the accommodation hole 82 opposite to the lower mold 46 side is covered with a base plate 74, and the escape from the accommodation hole 82 when the pressing pin 76 is pressed against the lead portion 28 is prevented. .

  When the upper die 48 and the lower die 46 are clamped, the pressing pin 76 accommodated and arranged in the accommodation hole 82 as described above cooperates with the support protrusion 56 projecting from the bottom surface 50 of the lower die 46, Each lead portion 28 is sandwiched.

  Then, with the upper mold 48 and the lower mold 46 being clamped and the magnetic sensor 12 and the permanent magnet 14 being positioned, the molding material 44 is filled with a material for forming the case 16 (synthetic resin material). Thereby, case 16 which accommodates magnetic sensor 12 and permanent magnet 14 in an embedded state is molded.

  At that time, a concave portion 42 corresponding to the convex engaging portion 24 formed on the outer peripheral surface 22 of the magnetic sensor 12 is integrally formed in the case 16. Thereby, the convex engaging portion 24 provided in the magnetic sensor 12 is fitted into the concave portion 42 formed integrally with the case 16. As a result, the engaging portion 24 of the magnetic sensor 12 is engaged with the case 16 so as to prevent the magnetic sensor 12 from coming out of the case 16.

  Thereafter, the upper die 48 is moved away from the lower die 46 to open the die, and the molded product is taken out from the molding die 44 with the ejector pins 86 provided on the lower die 46. Thereby, the target rotation detection apparatus 10 is obtained.

  In such a rotation detection device 10, since the detection side surface 18 of the magnetic sensor 12 is exposed on the surface 40 of the case 16, the case 16 does not exist between the metal rotor. Thereby, the attenuation of the magnetic force due to the presence of the case 16 between the detection side surface 18 of the magnetic sensor 12 and the metal rotor can be suppressed. As a result, the detection distance can be extended.

  Further, the magnet side surface 20 of the magnetic sensor 12 and the overlapping surface 36 of the permanent magnet 14 are directly overlapped with each other. Thereby, a stronger magnetic force can be exerted on the magnetic sensor 12. As a result, detection accuracy can be improved.

  In addition, since the convex engaging portion 24 protruding from the outer peripheral surface 22 of the magnetic sensor 12 is embedded in the case 16, the concave and convex engagement for firmly fixing the magnetic sensor 12 to the case 16 is facilitated. Realized. As a result, the detection side surface 18 can be exposed to the outside with a sufficiently large area while preventing the magnetic sensor 12 from slipping out of the case 16.

  Further, since the case 16 is molded in a state where the magnetic sensor 12 is sandwiched between the lower mold 46 and the permanent magnet 14, the magnetic sensor 12 is subjected to the pressure when the forming material of the case 16 is filled in the molding die 44. Can be prevented from being displaced or distorted. As a result, it is possible to prevent the generation of erroneous pulses due to the distortion of the magnetic sensor 12 or the like.

  In particular, since the permanent magnet 14 is elastically pressed by the contact biasing pin 60 to position the magnetic sensor 12 and the permanent magnet 14, the permanent magnet 14 is clamped when the upper die 48 and the lower die 46 are clamped. The occurrence of problems such as cracking can be prevented. The urging force of the contact urging pin 60 can be adjusted as appropriate by the coil spring 68.

  Further, the permanent magnet 14 is positioned in a direction orthogonal to the overlapping direction with the magnetic sensor 12 by four positioning protrusions 52 protruding from the bottom surface 50 of the lower mold 46. Thereby, it is possible to prevent the permanent magnet 14 from being displaced in a direction perpendicular to the overlapping direction with the magnetic sensor 12 due to the pressure when the molding material 44 is filled with the forming material of the case 16.

  Further, since the forming material of the case 16 is filled in the molding die 44 in a state where the pair of lead portions 28 and 28 are pressed by the pressing pins 76, the positioning state of the magnetic sensor 12 is further stabilized. It becomes possible.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the two positioning protrusions 52 projecting from the bottom surface 50 of the lower mold 46 are engaged with the two corners 54 positioned diagonally with respect to the permanent magnet 14 in plan view, whereby the permanent magnet 14. May be positioned.

10: rotation detection device, 12: magnetic sensor, 14: permanent magnet, 16: case, 18: detection side surface, 20: magnet side surface, 22: outer peripheral surface, 24: engagement portion, 28: lead portion, 29: plate shape Parts: 36: Overlapping surface, 40: Surface, 42: Recess, 44: Mold for molding, 46: Lower mold (divided mold), 50: Bottom surface, 52: Positioning protrusion, 60: Abutting biasing pin, 76: Push pin

Claims (4)

In the rotation detection device in which the case made of synthetic resin is molded with the magnetic sensor and the permanent magnet embedded,
In the magnetic sensor, the detection side surface and the magnet side surface are flat surfaces that are parallel to each other, the detection side surface of the magnetic sensor is exposed on the surface of the case, and a detection surface that faces the rotor is configured. In addition, the permanent magnet is directly superimposed on the magnet side surface of the magnetic sensor, and the engaging portion is engaged with the case on the outer peripheral surface of the embedded portion of the magnetic sensor in the case. The magnetic sensor is prevented from coming out of the case by the engaging portion , and
The magnetic sensor is integrally formed with a pair of flat lead portions, and the detection side surface of the magnetic sensor and the pair of lead portions extend in a parallel state, The case has a first pin hole formed on the surface of the permanent magnet opposite to the surface on which the magnetic sensor is superimposed to expose the permanent magnet, and the pair of the permanent magnet at a position away from the magnetic sensor. And a second pin hole for exposing the pair of lead portions . The rotation detecting device is provided with a second pin hole . A plate-like part in which a pair of lead portions are formed integrally, which is a magnetic sensor and a flat plate shape and the detection side and the magnet side are formed in parallel planes on the front and back each other, superimposed on the magnet side of the magnetic sensor And a permanent magnet provided with a plane-shaped overlapping surface, the detection side surface of the magnetic sensor is directly superimposed on the bottom surface of the split mold constituting the mold for molding the case , The pair of lead portions are set in a state extending along the bottom surface of the split mold, and the overlapping surfaces of the permanent magnets are set directly on the side surfaces of the magnet of the magnetic sensor, An abutting biasing pin that is elastically pressed against a surface of the permanent magnet opposite to a surface on which the permanent magnet is superimposed in the mold for molding the case is used to attach the permanent magnet to the magnetic sensor. Rutotomoni pressed against the direction superimposed with respect to support, said pressing pins abut so as to straddle the pair of lead portions at a position off a magnetic sensor, the pair of lead portions relative to the bottom surface of the split-type The case made of a synthetic resin that accommodates the magnetic sensor and the permanent magnet in an embedded state is filled by filling the mold for molding the case with a synthetic resin material while being pressed by the pressing pin. A method for manufacturing a rotation detecting device.   At least one concave or convex engaging portion is provided on the outer peripheral surface of the magnetic sensor, and a convex portion or a concave portion corresponding to the concave or convex engaging portion of the magnetic sensor is formed when molding the case. The method of manufacturing a rotation detecting device according to claim 2, wherein the magnetic sensor is prevented from coming out of the case by being integrally formed with the case.   As the permanent magnet, one that projects outward from the magnetic sensor in a state of being superimposed on the magnetic sensor is employed, and the split magnet is associated with a portion of the permanent magnet that projects from the magnetic sensor to the outer peripheral side. In combination, a plurality of positioning projections for projecting from the bottom surface of the split mold for positioning the permanent magnet in a direction perpendicular to the direction of superimposition on the magnetic sensor are used. The method for manufacturing a rotation detecting device according to claim 2 or 3, wherein the case is molded while being positioned on an overlapping surface with respect to the magnetic sensor.

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