Abstract:
A reel is provided including a cylindrical hub onto which a recording tape is wound; an upper flange that is integrally provided at the hub, and that extends from one end portion of the hub; and a lower flange that includes a bottom wall to which a reel plate is fixed, and that is welded to the other end portion of the hub, in order that deformations and surface runout of the flanges can be suppressed without increasing number of process and/or manufacturing costs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 USC 119 from Japanese Patent Application No. 2006-129656, the disclosure of which is incorporated by reference herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a reel around which a recording tape such as a magnetic tape used as a recording/playback medium for mainly computers and the like. 
         [0004]    2. Description of the Related Art 
         [0005]    Conventionally, a recording tape such as a magnetic tape is wound around a reel made from synthetic resin, and the tape is used as a data recording/playback medium (data backup) for devices such as computers. This is known as a recording tape cartridge where the reel is housed singly inside a case. The reel of this recording tape cartridge is formed from, e.g., a lower flange and hub integrally formed, and an annularly-shaped upper flange adhered to the upper peripheral edge of the hub. (See, for example, Japanese Patent Application Laid-Open (JP-A) No. 2001-135063.) 
         [0006]    In a reel of this type of configuration, in a metal mold used to integrally form the lower flange and hub, a gate for injecting resin material is positioned so as to correspond to a position of the bottom wall portion of the hub. Accordingly, the resin material injected through the gate flows once into the “hub side” of the metal mold, and after that, flows to the “lower flange side” of the metal mold. This is because the hub is thicker than the lower flange. However, in a case of this type of flow of resin material, there is a problem in that shrinkage and the like occur because the cooling times of the hub and lower flange differ, and the lower flange deforms. This causes surface runout in the lower flange to increase. Further, if the hub deforms due to tight winding of the recording tape, there is a danger of the upper flange adhered to the hub also deforming. 
         [0007]    Other reels are known, such as one where a hub having a bottom wall and an upper flange are integrally formed. The reel is formed by adhering an annularly-shaped lower flange to the peripheral edge of the bottom wall of the hub. (See, for example, Japanese Patent Application Laid-Open (JP-A) No. 2005-251272.) In this case, increase in surface runout in the upper flange can be suppressed, however, there is a problem in that, after adhering the lower flange to the hub, a reel plate made out of metal is fixed to the bottom wall of the hub. Accordingly, number of processes and manufacturing costs increase. 
         [0008]    Here, in light of the above-described circumstances, the present invention provides a reel with which deformation of the flange and surface runout of the flange can be suppressed, without increasing number of processes and manufacturing costs. 
       SUMMARY OF THE INVENTION 
       [0009]    A reel of a first aspect according to the present invention includes: a cylindrical hub onto which a recording tape is wound; an upper flange that is integrally provided at the hub, and that extends from one end portion of the hub; and a lower flange that includes a bottom wall to which a reel plate is fixed, and that is welded to the other end portion of the hub. 
         [0010]    According to the present invention of the first aspect, the lower flange has a bottom wall so when forming the lower flange, a reel plate can be fixed thereto with insert molding. That is, the lower flange to which the reel plate is fixed can be welded to the hub integrally formed with the upper flange. Accordingly, there are no drawbacks such as increases in number of processes and manufacturing costs. Further, the hub is integrally formed with the upper flange and the bottom wall is formed at the lower flange so deformations and surface runouts in the upper and lower flanges can be contained. 
         [0011]    The reel of a second aspect is the reel of the first aspect, wherein an engage portion is formed at the lower flange, and a portion that is engaged with the engage portion is formed at the other end portion of the hub. 
         [0012]    According to the present invention of the second aspect, positioning of the hub relative to the reel gear formed annularly at the outer side of the reel plate can be performed by engaging the engage portion and the portion that is engaged with the engage portion to be engaged. Due to this, the degree to which the reel gear and the hub are coaxial can be increased. 
         [0013]    Further, the reel of a third aspect is the reel of the first or second aspects, wherein the hub and the upper flange are integrally formed from a resin material with a metal mold, and a gate mark that corresponds to an injection port of the metal mold for injecting the resin material is formed at the other end portion of the hub. 
         [0014]    According to the present invention of the third aspect, the resin material flows without reverse flow from the hub side in the metal mold to the upper flange side in the metal mold, so pressure is distributed evenly from the hub to the upper flange. Accordingly, pressure loss during formation can decreased and surface runout of the upper flange can be decreased. 
         [0015]    Also, the reel of a fourth aspect is any one of the reels of the first through third aspects, wherein a plurality of depressions are formed in the lower flange. 
         [0016]    According to the present invention of the fourth aspect, air between the recording tape when winding the recording tape to the hub can be expelled through these depressions. Accordingly, the winding form of the recording tape can be made neat. 
         [0017]    Also, the reel of a fifth aspect is the reel of the first aspect, wherein the hub and the upper flange are integrally formed from a resin material with a metal mold, and an injection port for injecting the resin material is provided at the metal mold at a position corresponding to the other end portion of the hub. 
         [0018]    Also, the reel of a sixth aspect is the reel of the fourth aspect, wherein the plurality of depressions are formed with substantially constant intervals therebetween at an upper surface of the lower flange. 
         [0019]    Also, the reel of a seventh aspect is the reel of the second aspect, wherein the engage portion is formed at an upper surface of the lower flange as a convex portion, and the portion that is engaged with the engage portion is formed at the other end portion of the hub as a concave portion. 
         [0020]    Also, the reel of an eighth aspect is the reel of the first aspect, wherein the reel plate is fixed to the bottom plate by insert molding. 
         [0021]    Moreover, a reel of a ninth aspect is a reel including: a cylindrical hub onto which a recording tape is wound; an upper flange that is integrally provided at the hub, and that extends from one end portion of the hub; and a lower flange that includes a bottom wall to which a reel plate is fixed, and that is welded to the other end portion of the hub, wherein the hub and the upper flange are integrally formed from a resin material with a metal mold, and a gate mark that corresponds to an injection port of the metal mold for injecting the resin material is formed at the other end portion of the hub. 
         [0022]    As explained above, with the present invention, a reel can be provided where surface runouts and deformations of flanges can be suppressed, without increasing number of processes and manufacturing costs. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    An exemplary embodiment of the present invention will be described in detail with reference to the following figures, wherein: 
           [0024]      FIG. 1A  is an overall perspective drawing where a recording tape cartridge is viewed from above, and  FIG. 1B  is an overall perspective drawing where the recording tape cartridge is viewed from below; 
           [0025]      FIG. 2  is a cross-sectional drawing of when the reel of the recording tape cartridge is in a rotation-lock position; 
           [0026]      FIG. 3  is a cross-sectional drawing of when the reel of the recording tape cartridge is in a position where rotation is allowed; 
           [0027]      FIG. 4  is an exploded perspective drawing where the reel is viewed from above; 
           [0028]      FIG. 5  is an exploded perspective drawing where the reel is viewed from below; 
           [0029]      FIG. 6  is a flat drawing of the upper flange and reel hub; 
           [0030]      FIG. 7  is a bottom-surface drawing of the upper flange and reel hub; 
           [0031]      FIG. 8  is a flat drawing of the lower flange; 
           [0032]      FIG. 9  is a bottom-surface drawing of the lower flange; 
           [0033]      FIG. 10  is an exploded cross-sectional drawing of the reel; and 
           [0034]      FIG. 11  is a cross-sectional drawing of the reel. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Hereafter, the preferred embodiment for practicing the present invention will be explained in detail based on the exemplary embodiment shown in the drawings. Firstly, the overall configuration of a recording tape cartridge  10  will be explained. Note that for the sake of simplifying the explanations, the direction in which the recording tape cartridge  10  is loaded into a drive device is shown with an arrow marked “A”, and this indicates the forward direction (i.e., front side) of the recording tape cartridge  10 . Also, the direction that intersects perpendicularly with the direction of the A arrow is shown with an arrow marked “B”, and this indicates the right direction (i.e., right side) of the recording tape cartridge  10 . 
         [0036]    As shown in  FIGS. 1A ,  1 B,  2 ,  3 , the recording tape cartridge  10  is provided with a case  12 . The case  12  is structured by an upper case  14  and a bottom case  16  that are joined together. More specifically, the upper case  14  is formed from a substantially frame-shaped peripheral wall  14 B that is provided to stand along the outer edge of a substantially rectangular top panel  14 A (when viewed from top). The bottom case  16  is formed from a substantially frame-shaped peripheral wall  16 B that is provided to stand along the outer edge of a bottom panel  16 A formed to correspond approximately with the top panel  14 A. The case  12  has the upper case  14  and bottom case  16  joined by ultrasonic adhesion, fastened with screws or the like, in a state where the opening end of the peripheral wall  14 B and the opening end of the peripheral wall  16 B hit against each other. The case  12  is formed into a substantially rectangular box shape. 
         [0037]    An opening  18  that is slanted relative to the loading direction is formed in this case  12  by cutting away parts of each of the top panel  14 A, peripheral wall  14 B, bottom panel  16 A, and peripheral wall  16 B, in the corner portion of the case  12  at the leading-end side in the direction in which the case  12  is loaded into the drive device. Also, a circular gear opening  20  that passes through the bottom panel  16 A is formed approximately in the central portion of the bottom panel  16 A, and is used to expose a reel gear  44 , which will be described later. An annular rib  22  is provided at the edge portion of the gear opening  20  in the bottom panel  16 A so as to protrude towards the inner side of the case  12 . The annular rib  22  is used to position a reel  30 , which will be described later, and for dustproof. 
         [0038]    Also, a pair of positioning holes  24 ,  26  open in the front end vicinity of the outer surface of the bottom panel  16 A of the case  12 . The pair of positioning holes  24 ,  26  are provided so as to have bag-like shape in protrusions (not shown) set to stand from the bottom panel  16 A towards the inner side of the case  12 . These are arranged apart from each other on a hypothetical line in the direction of the B arrow. The positioning hole  24  that is at the side close to the opening  18  is formed in a substantially square shape when viewed from bottom and it circumscribes a positioning pin (not shown) of the drive device. The positioning hole  26  is a longitudinal hole that is long along the direction of the above-described hypothetical line and its width corresponds to the diameter of a positioning pin. Accordingly, this is configured so when the recording tape cartridge  10  is loaded into the drive device and the positioning pins are inserted into each of the positioning holes  24 ,  26 , the cartridge is properly positioned inside the drive device in the horizontal directions (i.e., left and right and front and back directions). 
         [0039]    Further, around the positioning holes  24 ,  26  on the bottom panel  16 A, reference surfaces  24 A,  26 A are made to be smoother than other portions (a design surface). The base surfaces  24 A,  26 A are made to come into contact with reference surfaces (not shown in drawings) of the drive device provided around the positioning pins when the positioning pins are inserted into the positioning holes  24 ,  26 . Due to this, this is configured so that the recording tape cartridge  10  is positioned in the vertical direction inside the drive device. 
         [0040]    Also, as shown in  FIGS. 2 and 3 , only one reel  30  (which will be described later) is rotatably housed inside the case  12 . A recording tape T such as magnetic tape is wound around this reel  30  and, as shown in  FIG. 1 , a leader block  28  is attached to the leading end of the recording tape T as a leader component. The leader block  28  is housed and retained at the inner side of the opening  18  of the case  12  when the recording tape cartridge  10  is not in use. Then, in this state, the leader block  28  seals the opening  18  and blocks the entering of dust and the like into the interior of the case  12 . 
         [0041]    Also, a hooking depression (a concave portion)  28 A is formed at the leading end of the leader block  28 . This is made so that when pulling the recording tape T out at the interior of the drive device, the tape is extracted from the case  12  with a pullout means (not shown) that engages with the hooking depression  28 A, and then guided to a windup reel (not shown) of the drive device. Further, the leader block  28  has an arced surface  28 B, at the end surface at the side opposite the hooking depression  28 A, which forms a portion of a surface that winds up the recording tape T by fitting into the reel hub of the windup reel. 
         [0042]    Next, the reel  30  and a braking member that prevents rotation of the reel  30  when the reel  30  is not in use will be explained. As shown in  FIGS. 4-7  and  10  and  11 , the reel  30  is provided with a reel hub  32  that forms the central axis portion of the reel  30 . The reel hub  32  has a cylinder  34  around whose external peripheral surface the recording tape T is wound, and an annular extension  36  provided integrally at the lower end portion of the cylinder  34  to extend annularly at a preset width towards the center of the reel hub  32 . Note that the width W of this annular extension  36  (see  FIG. 7 ) is made to be such that an engage gear  48  and standing ribs  52 , which will be described later, can be formed. 
         [0043]    An annular depression (annular concave portion)  36 A of a preset depth is formed at the undersurface of the annular extension  36  at the central side of the reel hub  32  as a portion that is engaged with. Note that plural expanded depressions (expanded concave portions)  36 B (in the drawings, three) are formed at preset intervals therebetween in the annular depression  36 A, and their areas in the diameter direction open and expand in arc shapes. Gates G are formed in the expanded depressions  36 B. Note that the “gate G” is a mark which is formed by a gate (an injection port) of a metal mold through which the resin material is filled. Also, an upper flange  38  is provided to extend towards the outer side in the direction of diameter coaxially and integrally with the peripheral edge of the upper end portion of the reel hub  32 . That is, the reel hub  32  and the upper flange  38  are made to be integrally formed from a resin material. 
         [0044]    A lower flange  40  to which a reel plate  46  is fixed (to be described later) is made to be joined (i.e., adhered) to the bottom end portion of the reel hub  32 . As shown in  FIGS. 4 ,  5 , and  8 - 11 , the outer diameter of the lower flange  40  is made to be the same as that of the upper flange  38 , and a bottom wall  42  having substantially the same diameter as that of the reel hub  32  is formed in the axial center portion. An annular stage (annular convex portion)  42 A that acts as an engage portion that engages with the annular depression  36 A is formed at a preset height on the upper surface of the bottom wall  42 . Plural expanded protrusions (expanded convex portions)  42 B (in the drawing, three) that fit into the expanded depressions  36 B are formed at preset intervals therebetween on the annular stage  42 A. Also, as shown in  FIGS. 8 and 10 , multiple (in the drawing, twelve) energy directors (hereafter, “ED”)  41  that are ribs for adhesion are provided at equal intervals so as to protrude at the upper surface of the bottom wall  42 . 
         [0045]    Accordingly, when adhering the lower flange  40  to the undersurface of the annular extension  36  of the reel hub  32 , the expanded protrusions  42 B are made to fit into the expanded depressions  36 B and the annular stage  42 A is made to fit into the annular depression  36 A, and fused with the ED  41  using ultrasonic waves generated from a horn (not shown). Due to this, the lower flange  40  (or rather, the reel gear  44  that will be described later) can be positioned to the reel hub  32  while adhering the undersurface of the annular extension  36  with the upper surface of the bottom wall  42 , and the recording tape T can be wound around the outer peripheral surface of the cylinder  34  of the reel hub  32  in the space between the surfaces of the upper flange  38  and lower flange  40 , which face each other. Note that multiple depressions (concave portions)  40 A (in the drawing, eight) are formed on the upper surface of the lower flange  40  at equal intervals therebetween and at a preset depth in shapes substantially like isosceles (equal leg) trapezoids. When winding the recording tape T up onto the cylinder  34  of the reel hub  32 , the air between the recording tape T can be expelled through the depressions  40 A. 
         [0046]    Also, as shown in  FIG. 9 , the annular reel gear  44  is formed coaxially with the reel hub  32  at the undersurface (i.e., outer surface) of the bottom wall  42  in the lower flange  40  when joined with the reel hub  32 . The reel gear  44  is made to be able to mesh with a drive gear  108  provided on the leading end of a rotation shaft  100  of the drive device, as shown in  FIGS. 2 and 3 . The teeth tips of this reel gear  44  protrude out downward further than the undersurface of the lower flange  40  and the bottoms of the teeth are positioned further to the upper side than the undersurface of the lower flange  40 . The outer end portion in the diameter direction of each tooth, from the central portion in the direction of tooth height to the bottom of the tooth, is linked with a tapered portion  43  which is formed continuously to the lower flange  40 . Also, plural gates G (in the drawing, three) are formed as injection ports for the resin material at preset positions on the reel gear  44 . Note that the “gate G” is a mark which is formed by a gate (an injection port) of a metal mold through which the resin material is filled. 
         [0047]    Further, the reel plate  46 , which is an annular metal plate made from a magnetic material, is coaxially and integrally fixed to the bottom wall  42  of the lower flange  40  by insert form at the inner side of the reel gear  44 . Accordingly, plural small holes  56  (in the drawing, four) are formed in the reel plate  46  and these are provided with step portions for the resin material to surround and fix to. Also, a through-hole  50  through which a clutch component  84 , which will be described later, is inserted is formed in the center (central axis portion) of the bottom wall  42  in the lower flange  40 . A short circular clutch boss  54  that acts as a guide wall portion is provided along the edge of the through-hole  50  to stand upward. This clutch boss  54  will be explained later along with the clutch component  84 . Note that the axial center of the reel plate  46  is through-hole  46 A and, as shown in  FIGS. 10 and 11 , the inner diameter of the through-hole  46 A is formed to be slightly smaller than the inner diameter of the through-hole  50 . 
         [0048]    Further, as shown in  FIG. 6 , an annular engage gear  48 , coaxially formed with the reel hub  32 , is formed on the upper surface of the annular extension  36  formed at the reel hub  32 . The engage gear  48  is made to be able to mesh with a braking gear  66  of a brake component  60 , which will be described later. Also, plural standing ribs  52  are provided (in the drawing, six) at equal intervals therebetween in the peripheral direction, at the outer side in the diameter direction of the engage gear  48 . The standing ribs  52  are at the inner surface of the cylinder  34  and on the upper surface of the annular extension  36 , each along the direction of the axial line of the reel  30 . Due to the existence of these standing ribs  52 , the engage gear  48  becomes positioned more to the inner side in the diameter direction than the reel gear  44 . Note that the standing ribs  52  will be described later with the brake component  60 . 
         [0049]    Also, as shown in  FIGS. 2 and 3 , the reel  30  is designed to be housed in the case  12  and placed on the annular rib  22  when not in use. More specifically, the reel  30  is so that the outer side portion of the tapered portion  43  in the bottom wall  42  comes into contact with the upper end surface of the annular rib  22 . The upper inner edge portion of the annular rib  22  has a tapered surface  22 A that corresponds with the tapered portion  43 , whereby movement in the diameter direction is restricted. Thus, this is configured so the entering of dust and the like therefrom is prevented. 
         [0050]    In this overall state, the reel  30  is positioned inside the case  12  and the reel gear  44  and reel plate  46  are exposed from the gear opening  20  (see  FIG. 1B ). That is, the reel gear  44  does not protrude out from the exterior surface (i.e., undersurface) of the bottom panel  16 A, rather, it is positioned outside but near of the case  12  from the gear opening  20 . Also, the through-hole  50  is positioned near at the gear opening  20  through the through-hole  46 A of the reel plate  46 . 
         [0051]    Due to this, operation of the reel  30  (i.e., chucking (retaining) and driving for rotation) is made possible from the exterior of the case  12 . Also, in this state, an annular restricting rib  58  provided so as to stand from the top panel  14 A enters into the upper portion of the cylinder  34  of the reel  30 . The restricting rib  58  makes the outer peripheral surface thereof adjoin the inner peripheral surface of the cylinder  34  (the reel hub  32 ), so the configuration is such where rattling of the reel  30  inside the case  12  is prevented. 
         [0052]    Also, the recording tape cartridge  10  is provided with the brake component  60  as a braking unit that blocks rotation of the reel  30  when it is not in use. The brake component  60  has a base  62 , which is formed into a substantially cylindrical shape, has a bottom, and is open downward. An annularly-shaped flat panel  64  is provided to extend from the center portion in the axial line direction at the outer peripheral portion of the base  62  to the outer side in the direction of diameter across the whole periphery, and the braking gear  66  is provided across the entire periphery at the undersurface of the flat panel  64 . That is, the entire braking gear  66  is annularly formed and is configured to be able to mesh with the engage gear  48  of the reel  30 . 
         [0053]    Also, a slide protrusion  68  is provided at the undersurface of the base  62  in the central axis portion. The leading end portion of the slide protrusion  68  is formed into a substantially ball-shaped surface and is made to touch at a point with the clutch component  84 , which will be described later. A cross-shaped protrusion  70  is provided to stand at the upper surface of the base  62  and is formed into what appears as a substantially cross-shaped groove in the interior. Also, an annularly-shaped rib  72  is provided so as to stand at the upper surface of the base  62 , and the upper surface of between the rib  72  and the cross-shaped protrusion  70  is made into a spring-receiving surface  74  that contacts one end of a compressed coil spring  76 , which will be described later. 
         [0054]    This kind of brake component  60  is movable in the up and down directions (in the axial line direction of the reel  30 ) in the cylinder  34  of the reel hub  32 , and is provided so as be inserted coaxially. That is, the brake component  60  moves in the up and down directions, whereby it can take a position where the braking gear  66  meshes with the engage gear  48  of the reel hub  32  (a rotation lock position) and a position that releases that meshing or engagement (a position allowing rotation). 
         [0055]    A cross-shaped rib  80  that is provided to protrude downward from the top panel  14 A of the case  12  is also made so as to enter into the groove of the cross-shaped protrusion  70  of the brake component  60 . The cross-shaped rib  80  is formed from two thin flat board pieces that intersect each other perpendicularly and meshes with the groove wall of the cross-shaped protrusion  70 , whereby it blocks rotation relative to the case  12  of the brake component  60 . Accordingly, the brake component  60  can block rotation of the reel  30  in a state where it has made the braking gear  66  mesh with the engage gear  48  of the reel hub  32 . 
         [0056]    Note that the cross-shaped rib  80  is made so that a state is maintained where it is entered into the groove across the entire movement stroke in the up and down directions of the brake component  60 . It is also configured to fulfill the function of guiding the direction of movement in the up and down directions. Also, the device is configured so when the brake component  60  is positioned in the rotation-lock position, movement in the diameter direction is restricted by the standing ribs  52  of the reel  30 . When positioned in the position where rotation is allowed, it does not interfere with the standing ribs  52  rotating with the reel  30 . 
         [0057]    That is, the standing ribs  52  are positioned to adjoin the outer peripheral edge of the flat panel  64  of the brake component  60  positioned in the rotation-lock position. Also, the top portion is cut away so that the intervals, which are at the outer peripheral edge of the brake component  60  positioned so that rotation is allowed, become over a preset value. Due to this, not only is movement of the reel  30  directly restricted by the case  12 , in the vicinity of the position of the center of gravity, movement in the diameter direction relative to the case  12  through the brake component  60  is restricted. The reel  30  is also stabilized by the lengthwise placed drive device (i.e., with the axial line of the reel  30  as the horizontal direction) and can thus be loaded. 
         [0058]    The compressed coil spring  76  is also is also arranged as, in a broad sense, a biasing unit that is gripped between the spring-receiving surface  74  of the brake component  60  and the top panel  14 A. One end portion of the compressed coil spring  76  comes into contact with the spring-receiving surface  74  and the other end portion comes into contact with the top panel  14 A. This other end portion is positioned at the inner side of the annular wall  78  provided to protrude toward the outer side of the cross-shaped rib  80  in the top panel  14 A, and is made so that the positioning does not slip in the diameter direction. 
         [0059]    The brake component  60  is biased downward due to the biasing force of this compressed coil spring  76 , and is configured to make the braking gear  66  always mesh with the engage gear  48  and prevent accidental rotation of the reel  30  with certainty (i.e., to make the brake component  60  in the rotation-lock position). Also, the reel  30  that is meshing with the brake component  60  at the engage gear  48  is also biased downward due to this biasing force so that it comes into contact with the annular rib  22  and does not rattle inside the case  12 . 
         [0060]    The recording tape cartridge  10  is also provided with the clutch component  84  that acts as a release component operated from the exterior when releasing the state where the reel  30  is locked by the brake component  60 . The clutch component  84  is made to be pressed upon by a releasing protrusion  110  of the drive device that will be described later and move upward with the action where the reel gear  44  meshes with the drive gear  108  of the drive device. The clutch component  84  is positioned between the bottom wall  42  of the reel  30  and the brake component  60 . 
         [0061]    That is, this clutch component  84  is shaped into a substantially columnar shape that is inserted through the through-hole  46 A and the through-hole  50 , and the outer diameter is slightly smaller than the through-hole  46 A of the reel plate  46 , i.e., the inner diameter of the through-hole  50  that is in accordance with the inner diameter of the clutch boss  54 . Also, the flat upper end surface of the axial center of the clutch component  84  is a slide surface  86  that is usually in contact with the slide protrusion  68  of the brake component  60 , and the flat lower end surface that opens downward around the provided hole is a press operation surface  88 . Accordingly, the configuration is such that when the press operation surface  88  of the clutch component  84  is pressed upon, it resists the biasing force of the compressed coil spring  76  and moves upward, thus moving the brake component  60  into the position that allows rotation. 
         [0062]    Also, this clutch component  84  is provided with rotation-restricting ribs  90  that project toward the outer side in the diameter direction further than the outer peripheral surface. Plural rotation-restricting ribs  90  (in the present embodiment, six) are provided at equal intervals in the peripheral direction of the clutch component  84  and each rotation-restricting rib  90  is arranged so that, when viewed as a flat surface, they appear in a radial pattern. Each rotation-restricting rib  90  protrudes upward higher than the slide surface  86  so as to span the upper end surface around the slide surface  86  of the clutch component  84  and the outer peripheral surface in the vicinity of that upper end surface (i.e., is linked respectively thereto). 
         [0063]    Each of the rotation-restricting ribs  90  is also made to enter respectively into rotation-restricting grooves  82  provided concavely (see  FIGS. 4 ,  8 ,  10  and  11 ) at the inner edge portion of the clutch boss  54 . That is, there are six rotation-restricting grooves  82  each provided at even intervals in the peripheral direction of the clutch boss  54  and these open upward at the upper edge of the clutch boss  54 . Due to this, the clutch component  84  is guided at the rotation-restricting ribs  90  by the rotation-restricting grooves  82  of the clutch boss  54  while movement in the up and down directions remains possible. 
         [0064]    Further, each of the rotation-restricting ribs  90  are made so that the state where they have entered into the rotation-restricting grooves  82  of the clutch boss  54  is maintained even when the clutch component  84  moves upward and positions the brake component  60  in the position that allows rotation. Due to this, the clutch component  84  is configured so that relative rotation to the reel  30  is impossible, i.e., to always rotate integrally with the reel  30 . Further, each rotation-restricting groove  82  is sealed at the bottom end portion of the clutch boss  54  so due to the rotation-restricting ribs  90  and the rotation-restricting grooves  82 , dropping out of the clutch component  84  from the reel hub  32  is prevented. 
         [0065]    Note that as shown in  FIGS. 2 and 3 , the rotation shaft  100  of the drive device is provided with a rotation axis  102 , and a circular rotation table  104  is provided integrally to extend from the upper end of the rotation axis  102 . The drive gear  108  is annularly formed on the upper surface of the rotation table  104  and at the outer peripheral edge portion so as to be able to engage with the reel gear  44  of the recording tape cartridge  10 . Also, a substantially circularly-formed magnet  106  is coaxially arranged on the upper surface of the rotation table  104  at the inner side in the diameter direction of the drive gear  108 . The releasing protrusion  110  that is in contact with the press operation surface  88  of the clutch component  84  is formed at the axial center portion of the rotation table  104 . 
         [0066]    Next, the operation of the recording tape cartridge  10  provided with the reel  30  configured as described above will be explained. When the recording tape cartridge  10  is not in use, the brake component  60  is positioned in the rotation-lock position due to the biasing force of the compressed coil spring  76  and the braking gear  66  is made to engage with the engage gear  48 . For this reason, rotation of the reel  30  relative to the case  12  is blocked. At this time, the reel gear  44  of the reel  30  is exposed from the gear opening  20  and the clutch component  84  is inserted through the through-hole  50  and through-hole  46 A and is positioned near at the gear opening  20 . 
         [0067]    When using the recording tape T, the recording tape cartridge  10  is loaded to the bucket (not shown) of the drive device along the direction of the A arrow. Then when the recording tape cartridge  10  has been loaded to the bucket up to a preset depth, the bucket moves downward and the rotation shaft  100  of the drive device approaches relatively (i.e., moves upward) toward the gear opening  20  of the case  12  and retains the reel  30 . More specifically, the rotation shaft  100  adsorbs and retains the reel plate  46  by the magnet  106  without contacting it and makes the drive gear  108  mesh with the reel gear  44 . 
         [0068]    In accompanying of the meshing of this reel gear  44  and drive gear  108 , that is, relative movement toward the side approaching in the axial direction of the rotation shaft  100  with respect to the case  12 , the releasing protrusion  110  of the rotation shaft  100  comes into contact with the press operation surface  88  of the clutch component  84 , and resisting the biasing force of the compressed coil spring  76 , pressing the clutch component  84  upward. Due to this, the brake component  60  that is in contact with the clutch component  84  also moves upward at the slide protrusion  68 , and the meshing between the braking gear  66  of the brake component  60  and the engage gear  48  is released. 
         [0069]    That is, the brake component  60  is made to move to a position that allows rotation relative to the reel  30 . After that, when the rotation shaft  100  moves relatively even further upward, resisting the biasing force of the compressed coil spring  76 , and the reel  30  is lifted upward with the clutch component  84  and brake component  60  (as is, without changing relative positioning). The brake component  60  reaches the position that allows rotation (relative to the case  12 ) and the lower flange  40  takes distance from the annular rib  22  (tapered surface  22 A). Due to this, the reel  30  rises (floats) inside the case  12  and becomes rotatable in a state of non-contact with the inner surface of the case  12 . 
         [0070]    Also, at this time, due to the bucket, i.e., recording tape cartridge  10  moving downward inside the drive device, positioning pins of the drive device enter into each of the positioning holes  24 ,  26  of the case  12  of the case  12 , and each of the reference surfaces  24 A,  26 A of the case  12  comes into contact with the reference surface of the drive device. Due to this, the recording tape cartridge  10  is positioned in the horizontal and vertical directions relative to the drive device. When this occurs, a pullout unit of the drive device engages with the hooking depression  28 A of the leader block  28 , extracts the leader block  28  from the case  12 , and leads it to the windup reel of the drive device. 
         [0071]    Then the leader block  28  is fitted into the reel hub of the windup reel and the arced surface  28 B forms one portion of the windup surface that winds or takes up the recording tape T. In this state, when the leader block  28  rotates integrally with the windup reel, the recording tape T is wound up to the reel hub of the windup reel and is pulled out from the case  12  through the opening  18 . Note that at this time, the reel  30  of the recording tape cartridge  10  rotates in synchronization with the windup reel due to the rotation force of the rotation shaft  100  which force is transmitted by the drive gear  108  which is engaged with the reel gear  44 . 
         [0072]    Then the recording of data to the recording tape T or the playback of data recorded on the recording tape T is performed with a recording/playback head (not shown) arranged along a preset tape path of the drive device. Note that at this time, the slide protrusion  68  of the brake component  60  that cannot rotate relative to the case  12  slide-contacts against the slide surface  86  of the clutch component  84  that rotates, relative to the case  12 , together with the reel  30 . That is, the configuration is such where the clutch component  84 , in a state where the reel gear  44  is meshing or engaged with the drive gear  108 , maintains the state of contact with the releasing protrusion  110  at the press operation surface  88  and the brake component  60  is retained in the position that allows rotation. 
         [0073]    Then when the reel  30  rotates, there is no relative rotation between the clutch component  84  that rotates integrally with the reel  30  and the rotation shaft  100  that drives the reel  30 , and is configured so the press operation surface  88  and the releasing protrusion  110  do not slide-contact against each other. It is configured so that the slide surface  86  of the clutch component  84  and the slide protrusion  68  of the brake component  60  (which cannot rotate relative to the case  12 ) slide-contact against each other. In this manner, there is no relative rotation between the rotation axis  102  and the clutch component  84 , so there are no problems such as wearing of the releasing protrusion  110  and/or the press operation surface  88 . 
         [0074]    Meanwhile, when the recording of data to the recording tape T or the playing back of data recorded on the recording tape T is finished, the recording tape T is rewound to the reel  30  and the leader block  28  is retained in the vicinity of the opening  18  of the case  12 . Then the bucket into which the recording tape cartridge  10  is loaded rises. When this occurs, the engaging between the reel gear  44  and the drive gear  108  is released, and contact between the releasing protrusion  110  and the press operation surface  88  of the clutch component  84  is released. The clutch component  84  moves downward with the brake component  60  (while maintained in a state of contact) due to the biasing force of the compressed coil spring  76 . 
         [0075]    Due to this, the braking gear  66  of the brake component  60  meshes with the engage gear  48  and the brake component  60  returns to the rotation-lock position that blocks rotation of the reel  30  relative to the case  12 . Also, the reel  30  also moves downward with the action of movement of the brake component  60  and clutch component  84  due to the biasing force of the compressed coil spring  76 . The lower flange  40  is made to contact the annular rib  22  while the reel gear  44  is reverted to the beginning state where the reel gear  44  is exposed from the gear opening  20 . In this state, the recording tape cartridge  10  is ejected from the drive device (bucket). 
         [0076]    Here, the upper flange  38  and the reel hub  32  are integrally formed. The reel  30  is made by welding the lower flange  40  that has the bottom wall  42  to the reel hub  32  integrally formed with the upper flange  38 . Then the reel plate  46  is fixed to the bottom wall  42  in advance with insert molding. That is, when the lower flange  40  is welded to the reel hub  32 , the reel plate  46  is already in a state where it is fixed to the bottom wall  42 . Accordingly, this has merits such as the number of processes and manufacturing costs can be reduced, as opposed to conventional processes where the reel plate  46  is attached after welding the lower flange  40  to the reel hub  32 . 
         [0077]    Further, since the upper flange  38  and reel hub  32  are integrally formed, in the metal mold, the position of the gate through which the resin material flows can be provided at a position corresponding to the annular extension  36  of the reel hub  32  (expanded depressions  36 B). That is, if the gate G is formed in such a position, the resin material flows into a side of the metal mold corresponding to the reel hub  32  and fills while flowing into a side of the metal mold corresponding to the upper flange  38  so there are no problems such as such as in conventional technologies like reverse flow of the resin material at the portion where the reel hub  32  is formed, and pressure is evenly distributed from the reel hub  32  to the upper flange  38 . Accordingly, pressure loss during formation with a metal mold can be decreased, the strength of the upper flange  38  and the reel hub  32  can be improved, and the surface runout on the upper flange  38  relative to the reel hub  32  can be decreased. 
         [0078]    Further, the gates G are formed on the reel gear  44  as well as the lower flange  40  so, unlike conventionally, there are no problems such as reverse flow of the resin material, and pressure is evenly distributed from the bottom wall  42  to the lower flange  40 . Accordingly, pressure loss during formation with the metal mold can be decreased and the strength of the lower flange  40  can be improved. Then, since this lower flange  40  is welded to the reel hub  32 , the surface runout of the lower flange  40  relative to the reel hub  32  can also be decreased. That is, due to this type of configuration, the surface runouts of the upper flange  38  and the lower flange  40  can be suppressed. Also, the occurrence of problems such as the upper flange  38  and lower flange  40  deforming, caused by the tight winding that occurs when the recording tape T is wound to the reel hub  32 , and touching the recording tape T thereto can be prevented. 
         [0079]    Further, when welding the lower flange  40  to the reel hub  32 , the annular stage  42 A and expanded protrusions  42 B formed on the bottom wall  42  of the lower flange  40  are fit together with the annular depression  36 A and expanded depressions  36 B formed on the annular extension  36  of the reel hub  32 , so positioning of the reel hub  32  relative to the reel gear  44  formed on the bottom wall  42  of the lower flange  40  can be performed. That is, the degree to which the reel gear  44  and the reel hub  32  are in a coaxial state can be secured at the optimum level. Also, plural depressions  40 A of preset depth are formed on the upper surface of the lower flange  40  so air between the recording tape T when it is wound to the reel hub  32  can be expelled from those depressions  40 A. Due to this, the winding form of the recording tape T to the reel  30  (reel hub  32 ) can be made neat. 
         [0080]    Note that in the recording tape cartridge  10  of the above-described embodiment, the configuration is such where there is the leader block  28  that acts as the leader component, however, the recording tape cartridge  10  is not limited to the above-described embodiment. For example, the configuration can be made so that a cylindrical leader pin (not shown) acts as the leader component. Also, the configuration can be made to have a shielding component that opens and closes the opening  18  (e.g., a slide door (not shown) that moves along a preset straight line or arc). Furthermore, it is sufficient if the recording tape T can be a member that is recognized, acts as a long tape-shaped data recording/playback medium with which the recording of data and playback of recorded data is possible. It is also a given that the recording tape cartridge  10  (reel  30 ) can also be applied to the recording tapes T of any types of recording/playback systems.