JP5600401B2 - DISC MOLD, INNER HOLDER, AND METHOD FOR MANUFACTURING DISC MOLD - Google Patents

Description

  The present invention relates to a disk molding die, an inner holder, and a method for manufacturing a disk molding die.

  2. Description of the Related Art Conventionally, in an injection molding machine for molding a disk substrate, a resin heated and melted in a heating cylinder is filled into a mold apparatus, that is, a cavity space in a disk molding mold, and the cavity A disk substrate is obtained by cooling in the space and drilling.

  In the disk molding die, an annular stamper is detachably attached to the mirror plate of the fixed side mold assembly or the movable side die assembly, and the fine pattern of the stamper is placed in the cavity space. It is transferred to the resin. The stamper is attached to the mirror plate by an inner stamper holder at the inner periphery.

  FIG. 2 is a cross-sectional view showing a main part of a conventional disk molding die.

  In the figure, 16 is a mirror plate disposed on the mold assembly on the fixed side, 29 is a stamper removably disposed on the front end surface of the mirror plate 16, and 30 is the stamper 29 attached to the mirror plate 16. An inner holder 36 for the mirror, a mirror plate disposed in the movable mold assembly, and C a cavity space.

  The inner holder 30 has an annular presser foot 58 so that the stamper 29 does not fall off the mirror plate 16 when the disk substrate formed in the cavity space C is released from the stamper 29 when the mold is opened. And the presser margin 58 mechanically holds the inner periphery of the stamper 29 and presses it against the mirror plate 16.

  By the way, due to dimensional tolerances in manufacturing the stamper 29 and the inner holder 30, and in order to facilitate the mounting of the stamper 29 and the inner holder 30, there is a clearance between the front end surface of the mirror plate 16 and the rear end surface of the presser allowance 58. CL1 has a clearance CL2 formed between the inner peripheral surface of the stamper 29 and the outer peripheral surface of the inner holder 30, but if the clearance CL1 is unnecessarily large, resin enters the clearance CL1 and burrs are generated on the disk substrate. As a result, the quality of the disk substrate is degraded.

  Therefore, in order to prevent the resin from entering between the stamper 29 and the inner holder 30 to generate burrs, the front edge of the inner holder 30 is protruded forward and radially outward. The presser allowance 58 is formed (see, for example, Patent Document 1).

JP-A-9-117937

  However, in the conventional disk molding die, the presser allowance 58 needs to be sufficiently large so that the stamper 29 does not fall off the mirror surface plate 16, so the stamper 29 and the presser allowance 58 A large step is formed between the two.

  Along with this, a large step is formed on the molded disk substrate, which deteriorates the appearance of the disk substrate.

  Further, the portion where the presser allowance 58 is formed in the cavity space C becomes narrow, and the flow of the resin filled in the cavity space C is disturbed. As a result, the quality of the disk substrate is degraded.

  The present invention solves the problems of the conventional disk molding mold, improves the appearance of the disk substrate, and improves the quality of the disk substrate, the disk molding mold, the inner holder, and the disk It aims at providing the manufacturing method of the metal mold | die for shaping | molding.

  Therefore, in the disk molding die of the present invention, the mirror plate, a stamper formed in the center and attached to the front end surface of the mirror plate, and the stamper is pressed into the hole. And an inner holder for holding.

  The inner holder includes an inner holder main body and a projecting portion formed integrally with the inner holder main body so as to protrude outward in the radial direction on the outer peripheral edge of the front end of the inner holder main body.

Moreover, the press-fit deformation portion set in at least one of the stamper and the inner holder is plastically deformed by the stress exceeding the yield point as the press-fitting is performed.
And the said overhang | projection part is protruded toward the radial direction outer side so that the inner peripheral surface and peripheral edge part of the hole of the said stamper may be covered, and the said outer periphery of an overhang | projection part is performed as the said press fit is performed The press-fit deformation portion is deformed more radially inward, and the overhang portion covers the press-fit deformation portion.

  According to the present invention, in the disk molding die, the mirror plate, a stamper formed in the center and attached to the front end surface of the mirror plate, and the stamper is mounted by press-fitting into the hole. And an inner holder for holding.

  The inner holder includes an inner holder main body and a projecting portion formed integrally with the inner holder main body so as to protrude outward in the radial direction on the outer peripheral edge of the front end of the inner holder main body.

Moreover, the press-fit deformation portion set in at least one of the stamper and the inner holder is plastically deformed by the stress exceeding the yield point as the press-fitting is performed.
And the said overhang | projection part is protruded toward the radial direction outer side so that the inner peripheral surface and peripheral edge part of the hole of the said stamper may be covered, and the said outer periphery of an overhang | projection part is performed as the said press fit is performed The press-fit deformation portion is deformed more radially inward, and the overhang portion covers the press-fit deformation portion.

  In this case, when the inner holder is press-fitted into the hole, the stamper is held, and at least one of the stamper and the inner holder is plastically deformed. Therefore, a step formed between the stamper and the overhanging portion is reduced. The stamper can be held in a stable state by the inner holder without increasing the size. In addition, the appearance of the disk substrate can be improved.

  Further, since it is possible to prevent the molding material from entering between the inner holder and the stamper, it is possible not only to prevent the occurrence of burrs on the disk substrate, but also to form a protruding portion in the cavity space. Since the portion does not become narrow, it is possible to suppress the occurrence of disturbance in the flow of the molding material filled in the cavity space. Therefore, the quality of the disk substrate can be improved.

It is sectional drawing which shows the principal part of the metal mold | die for disk shaping | molding in the 1st Embodiment of this invention. It is sectional drawing which shows the principal part of the conventional disk shaping die. It is sectional drawing of the metal mold | die for disk formation in the 1st Embodiment of this invention. It is a figure which shows the modification of the disk shaping die in the 1st Embodiment of this invention. It is sectional drawing which shows the principal part of the metal mold | die for disk formation in the 2nd Embodiment of this invention. It is sectional drawing which shows the principal part of the metal mold | die for disk formation in the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a disk forming mold as a mold apparatus will be described.

  FIG. 1 is a cross-sectional view showing the main part of a disk molding die according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of the disk molding die according to the first embodiment of the present invention. These are figures which show the modification of the disk shaping die in the 1st Embodiment of this invention.

  In the figure, 12 is a fixed-side mold assembly as a first mold attached to a fixed platen (not shown) by a bolt (not shown), and 32 is a second mold attached to a movable platen (not shown) by a bolt (not shown). The mold assembly on the movable side is a mold for disk formation as a mold apparatus. In the description of the disk molding die, in the mold assembly 12, the mold assembly 32 side is the front and the stationary platen side is the rear according to the flow of the resin as the molding material. In the mold assembly 32, the mold assembly 12 side is defined as the front and the movable platen side is defined as the rear according to the operation of the movable platen.

  A mold clamping mechanism (not shown) is provided behind the movable platen, and the mold plate 32 is advanced and retracted by operating the mold clamping mechanism to advance and retract the mold assembly 12. Thus, the disk molding die can be closed, clamped and opened. When the mold is closed and clamped, a cavity space C is formed between the mold assembly 12 and the mold assembly 32.

  A mold clamping device is constituted by the fixed platen, the movable platen, the mold clamping mechanism, and the like. An injection molding machine as a molding machine is constituted by the disk molding die, a mold clamping device, an injection device (not shown), and the like.

  The mold assembly 12 includes a base plate 15, a mirror surface plate 16 attached to the base plate 15 with bolts 17, a radially outer side than the mirror surface plate 16, and an annular shape attached to the base plate 15 with bolts 19. The guide ring 18 is disposed in the base plate 15 so as to face the fixed platen, and is disposed adjacent to the locate ring 23 for positioning the base plate 15 with respect to the fixed platen, and the base plate 15. And a sprue bushing 24 extending forward through the specular disc 16.

  At the center of the sprue bushing 24, a sprue 26 through which resin injected from the injection nozzle of the injection device is passed is formed. The sprue bushing 24 is disposed with its front end facing the cavity space C, and a cut portion 28 formed of a recess is formed at the front end.

  An annular stamper 29 having a hole formed in the center is attached to the front end surface of the mirror surface plate 16, and the stamper 29 has a fine pattern formed of minute irregularities on the front end surface. The stamper 29 is held by being pressed against the mirror surface plate 16 by an outer holder whose outer peripheral edge is not shown and by an inner holder 60 at an inner peripheral edge. The mold assembly 12 is also provided with a fixed side air probe or the like (not shown).

  On the other hand, the mold assembly 32 includes a base plate 35, an intermediate plate 40 as a support member attached to the base plate 35 with bolts 37, a mirror surface plate 36 attached to the intermediate plate 40 with bolts 42, and the mirror surface plate 36. An annular guide ring 38, which is disposed more radially outward and is attached to the intermediate plate 40 by a bolt 39, is disposed in the base plate 35 so as to face the movable platen, and is attached to the intermediate plate 40 by a bolt 45. A cut punch 48 is provided so as to face the attached guide member 44 and the sprue bush 24 and to be movable forward and backward with respect to the guide member 44. The front end of the cut punch 48 is the cut portion 28. It has a shape corresponding to.

  An annular cavity ring 33 is provided on the outer peripheral edge of the surface of the mirror surface plate 36 facing the mirror surface plate 16 so as to protrude toward the mirror surface plate 16 by an amount corresponding to the thickness of the disk substrate to be molded. Is done. In FIG. 3, the cavity ring 33 is shown integrally with the mirror surface plate 36. However, in actuality, the cavity plate 33 is formed separately from the mirror surface plate 36, and via a spring (not shown) as an urging member. 36 is arranged so as to be able to advance and retreat.

  A recess is formed radially inward from the cavity ring 33, and the recess forms a cavity space C together with the mold assembly 12 when the mold is closed.

  A flange 51 formed integrally with the cut punch 48 is disposed in the guide member 44 so as to freely advance and retract. A drive cylinder (not shown) as a drive unit is disposed behind the flange 51, and the drive The flange 51 can be moved forward by driving the cylinder. Further, a cut punch return spring 52 is disposed in front of the flange 51 between the intermediate plate 40, and the cut punch return spring 52 biases the flange 51 rearward with a predetermined biasing force. To do.

  The mold assembly 32 is also provided with unillustrated eject tabs, ejector pins, movable air probes, and the like.

  In the disk molding die having the above structure, when the mold clamping mechanism is operated to advance the movable platen and advance the mold assembly 32, the mold is closed and the guide rings 18 and 38 are connected. The cavities 33 are aligned with the mirror plate 16 and the stamper 29 by brazing. Then, the mold clamping mechanism is further operated to perform mold clamping, and when the molten resin is injected from the injection nozzle in the mold clamping state, the resin enters the cavity space C via the sprue 26. At this time, the fine pattern of the stamper 29 is transferred to the resin. Subsequently, the resin is cooled and solidified to form a prototype substrate that becomes a prototype of a disc substrate as a molded product. In order to join the guide rings 18 and 38 to each other, annular recesses 18a and 38a are formed on the inner peripheral side of the guide ring 18 and the outer peripheral side of the guide ring 38, respectively. Further, in order to cool the resin in the cavity space C, a temperature adjusting flow channel 55 is formed in the mirror surface plate 16, and a temperature adjusting flow channel 56 is formed in the mirror surface plate 36. A temperature adjusting medium supplied from a temperature controller (not shown) is flowed.

  Subsequently, when the flange 51 is advanced by driving the drive cylinder, the cut punch 48 is advanced, the front end of the cut punch 48 enters the cut portion 28, and the original substrate in the cavity space C. Drilling is performed. Then, by further cooling the original substrate that has been subjected to drilling, a disk substrate is formed.

  Next, when the mold clamping mechanism is operated to retract the movable platen and retract the mold assembly 32, the mold is opened and the disk substrate is released from the stamper 29. Subsequently, the ejector pin is advanced, the disk substrate is ejected, and the mold assembly 32 is released. In this way, the disk substrate is formed.

  By the way, when the mold substrate is opened, when the disk substrate molded in the cavity space C is released from the stamper 29, the inner holder 60 is provided with the stamper 29 so that the stamper 29 does not fall off the mirror plate 16. Hold.

  For this purpose, a locking mechanism (not shown) is provided in the base plate 15. The locking mechanism is formed at an operation rod that is rotatably extended from the outside of the disk molding die to the vicinity of the outer peripheral surface of the inner holder 60, and is formed at a tip of the operation rod. , A locking portion having a semicircular shape is provided, and by rotating the operating rod, the locking portion and the rear end of the inner holder 60 are locked, and the inner holder 60 is retracted. Therefore, a locked portion is formed at the rear end of the inner holder 60 so as to correspond to the locking portion. In order to regulate the amount of retreat of the inner holder 60, it is not shown as a stop member at a predetermined location on the base plate 15 or the specular panel 16, in this embodiment, at a predetermined location behind the inner holder 60 in the base plate 15. A stopper is provided.

  Then, in a state where the stamper 29 is pressed against the mirror surface plate 16, the inner holder 60 is inserted into the holes formed in the stamper 29 and the mirror surface plate 16, and the rear end of the inner holder 60 and the locking portion are locked. When the mechanism is operated, the inner holder 60 is retracted, and accordingly, the stamper 29 is held and pressed against the mirror surface plate 16.

  By the way, a hole is formed in the center of the stamper 29. When the hole is formed by punching, the vicinity of the hole at the front end portion of the stamper 29 is deformed obliquely rearward as shown in FIG. Accordingly, a slight clearance CL3 may be formed between the inner holder 60 and the stamper 29. In this case, if the resin enters the clearance CL3, burrs are generated on the disk substrate.

  Therefore, in the present embodiment, an annular protrusion 62 as an overhanging portion protrudes radially outward from the outer periphery of the inner holder 60 main body, that is, the front end of the inner holder main body 61, and The inner holder main body 61 is integrally formed. Further, the inner holder 60 is driven from the front and is press-fitted into the hole of the stamper 29.

  The protrusion 62 is formed linearly from the outer peripheral edge of the flat front end surface s1 of the inner holder main body 61 toward the radially outer side. The front end surface s2 constituting the flat portion, and the outer peripheral edge of the front end surface s2 A cylindrical surface s3 formed from the rear side toward the rear side, and a conical inclined surface s4 formed by curving from the rear end of the cylindrical surface s3 obliquely rearward and radially inward. Is provided.

  In the present embodiment, the inclined surface s4 is formed obliquely rearward from the rear end of the cylindrical surface s3 and radially inward, and the rear surface of the cylindrical surface s3 of the projecting portion 62. A predetermined curve is drawn between the end point p1 and the front end point p2 of the cylindrical surface s5 of the inner holder body 61, and the diameter representing the distance from the center of the inner holder 60 is continuously changed. The closer to p1, the larger, and the closer to point p2, the smaller. The inclined surface s4 has a predetermined radius of curvature so that the tangent at the point p1 substantially coincides with the front end surface of the stamper 29 and the tangent at the point p2 coincides with the cylindrical surface s5 of the inner holder body 61. It is formed. At the point p1, the cylindrical surface s3 and the inclined surface s4 are crossed at an angle of approximately 90 [°].

  Further, a press-fit deformation portion is set on the inclined surface s4, the inner peripheral surface s6 of the hole of the stamper 29, and the peripheral edge portion q1 of the hole on the front end surface of the stamper 29 (the outer portion in the radial direction from the broken line in FIG. 1), The inner holder 60 is press-fitted in the press-fitted deformation portion. As the press-fitting is performed, a stress exceeding the yield point of the material forming the stamper 29 is generated in at least one of the inner holder 60 and the stamper 29, in this embodiment, the stamper 29. To do. As a result, the stamper 29 is plastically deformed, and the inner peripheral surface s6 and the peripheral edge q1 of the hole are deformed along the shape of the inclined surface s4. Note that s6 'represents the inner peripheral surface of the hole after deformation, and q1' represents the peripheral edge of the hole after deformation.

  Therefore, the stamper 29 is made of a first material suitable for plastic deformation, for example, pure nickel, and the inner holder 60 is made of a second material having a hardness higher than that of pure nickel, for example, stainless steel. Is done. In order to plastically deform the stamper 29, as shown in FIG. 1, at each position in the axial direction in front of the point p2, the diameter of the inclined surface s4 is larger than the diameter of the inner peripheral surface s6 of the hole. Increased.

  Thus, in the present embodiment, the inner holder 60 is driven from the front and is press-fitted into the hole of the stamper 29, so that the inner periphery of the stamper 29 is held without increasing the protrusion 62, and the stamper 29 Can be pressed against the mirror plate 16.

  In addition, since it is not necessary to increase the protrusion 62, the step formed between the stamper 29 and the protrusion 62 can be reduced. Therefore, the appearance of the disk substrate can be improved. Further, since the portion where the protrusion 62 is formed in the cavity space C is not narrowed, it is possible to suppress the occurrence of turbulence in the flow of the resin filling the cavity space C. Therefore, the quality of the disk substrate can be improved.

  In the present embodiment, the tangent of the point p1 on the inclined surface s4 of the protrusion 62 is formed so as to substantially coincide with the front end surface of the stamper 29, and the predetermined distance from the point p1 to the front on the outer peripheral edge of the protrusion 62. A cylindrical surface s3 extending in the axial direction over the distance is formed, and at the point p1, the cylindrical surface s3 and the inclined surface s4 intersect at an angle of approximately 90 °.

  In this case, when the inner holder 60 is press-fitted into the hole of the stamper 29, if the stamper 29 is plastically deformed, the cylindrical surface s3 enters the stamper 29 by a slight amount. Inside, the cylindrical surface s3 and the inclined surface s4 intersect at an angle of approximately 90 [°].

  Therefore, even if the clearance CL3 is slightly formed between the inner holder 60 and the stamper 29, the resin is prevented from entering at the portion where the cylindrical surface s3 and the inclined surface s4 intersect, so that burrs are generated on the disk substrate. Can be prevented. As a result, the quality of the disk substrate can be improved.

  In the present embodiment, a press-fit deformation portion is locally formed in front of the point p2 in the axial direction of the stamper 29. However, as shown in FIG. By making the diameter of the inclined surface s4 larger than the diameter of the inner peripheral surface s6 of the hole at each position, a press-fit deformation portion can be formed entirely in the axial direction of the stamper 29.

  In the present embodiment, the press-fit deformation portion is formed over the entire circumferential direction of the stamper 29 and the inner holder 60, but a predetermined portion (for example, an equal pitch angle) in the circumferential direction of the stamper 29 and the inner holder 60 is used. Can be formed locally at a plurality of locations.

  Incidentally, in the present embodiment, the stamper 29 is plastically deformed as the inner holder 60 is press-fitted, but the plastic deformation is generated in the stamper 29 by a force applied from the outside. This occurs when the stress to be generated becomes larger than the yield point that becomes the limit of elastic deformation of the material forming the stamper 29.

  In the elastic deformation, when a force is applied from the outside, a distortion corresponding to the applied force is generated and a stress is generated inside, but when the force is not applied from the outside, the original shape is restored. The strain becomes zero (0) and the internal stress becomes zero. Therefore, if the stamper 29 is elastically deformed and the inner holder 60 is press-fitted, a force is applied from the outside, and the stress generated in the stamper 29 remains as it is.

  On the other hand, in the plastic deformation, when a force is applied from the outside, a strain corresponding to the applied force is generated. While the amount of strain is changing, a stress is generated inside, but the strain is When the quantity stops changing, the internal stress becomes zero. And even if force is not applied from the outside, it does not return to its original shape and the distortion does not become zero. Also, the internal stress remains zero. Therefore, the stress generated in the stamper 29 as the inner holder 60 is press-fitted into the hole of the stamper 29 becomes zero and does not remain.

  As a result, once the inner holder 60 is attached to the mirror plate 16 and press-fitted, no stress remains in the stamper 29 at the plastically deformed portion, so that the stamper 29 can be attached in a more stable state.

  As the inner holder 60 is press-fitted, if there is a portion where a stress smaller than the yield point is applied around the portion of the stamper 29 that is plastically deformed, the stamper 29 is elastically deformed at that portion. . Further, the inner holder 60 is not subjected to a stress exceeding the yield point of the material forming the inner holder 60, and the inner holder 60 is elastically deformed.

  As a result, after the inner holder 60 is press-fitted into the hole of the stamper 29, a slight clearance may be formed between the inclined surface s4 and the inner peripheral surface s6 'of the hole. As described above, since the resin is prevented from entering at the portion where the cylindrical surface s3 and the inclined surface s4 intersect, it is possible to prevent burrs from being generated on the disk substrate.

  In the protrusion 62, the inclined surface s4 forms a press-fitted deformation portion and has a function of holding the inner peripheral edge of the stamper 29, whereas the cylindrical surface s3 has a function of preventing the resin from entering. Therefore, it is not necessary to increase the dimension L1 of the cylindrical surface s3 in the axial direction (the thickness of the tip of the protrusion 62). Therefore, in the present embodiment, the dimension L1 is made smaller than the thickness of the tip of the conventional presser allowance 58 (FIG. 2). It should be noted that the protrusion amount 62 (distance between the cylindrical surfaces s3 and s5 in the radial direction of the inner holder 60) L2 is such that the tangent to the point p1 and the front end surface of the stamper 29 substantially coincide with each other. It is made larger than the overhang amount of 58.

  In the present embodiment, since the dimension L1 is reduced, the cavity space C is not reduced. Therefore, the fluidity of the resin filled in the cavity space C is improved, and it is possible to prevent the flow line from being formed on the surface of the disk substrate and the warpage of the disk substrate. As a result, the quality of the disk substrate can be improved.

  Further, since no clearance is formed between the stamper 29 and the inner holder 60 in the radial direction, the stamper 29 is not eccentric with respect to the mirror surface plate 16 in the radial direction. Therefore, there is no deviation between the center of the disk substrate and the center of the information surface composed of the fine pattern transferred to the resin, and the quality of the disk substrate can be further improved.

  Furthermore, since the diameter of the inclined surface s4 is increased as the point p1 is closer, the stamper 29 does not fall off from the front end side of the inner holder 60 even if a force is applied to the stamper 29. Therefore, the stamper 29 can be reliably held. In this case, the protrusion 62 constitutes a slip prevention portion that prevents the stamper 29 from slipping out of the inner holder 60.

  When the stamper is elastically deformed, the stamper is not firmly held by the inner holder, and the stamper may be eccentric in the radial direction, whereas in the present embodiment, the stamper 29 is plastically deformed. Since the stamper 29 is firmly held by the inner holder 60, the stamper 29 is not eccentric in the radial direction. Therefore, there is no deviation between the center of the disk substrate and the center of the information surface composed of the fine pattern transferred to the resin, and the quality of the disk substrate can be further improved.

  In forming the stamper 29, punch holes are formed by pressing a pure nickel disk. At this time, even when the accuracy of the punch hole is not high, when the stamper 29 is attached to the mirror plate 16, the stamper 29 is positioned with respect to the mirror plate 16 based on the information surface, and the inner holder 60 is press-fitted in that state. Thus, the positioning accuracy of the stamper 29 can be increased. Therefore, the stamper 29 is not eccentric in the radial direction.

  In the present embodiment, only the stamper 29 of the stamper 29 and the inner holder 60 is plastically deformed. However, the inner holder 60 is plastically deformed and press-fitted without plastically deforming the stamper 29. Can also be done. In this case, the inner holder 60 is configured by contacting the stamper 29 and using a portion in the vicinity of the plastically deformed surface as a replacement part, and detachably disposing the replacement part with respect to other parts. Therefore, when the stamper 29 cannot be smoothly press-fitted, it is possible to perform press-fitting by replacing only the replacement part of the inexpensive inner holder 60 without replacing the expensive stamper 29. Furthermore, the stamper 29 and the inner holder 60 can be press-fitted by plastic deformation.

  By the way, for example, when the disc as a finished product is a Blu-ray disc, a reflective film, a cover layer, a hard coat layer, etc. are laminated on the disc substrate so as to face the information surface, and the cover layer, the hard coat layer, etc. It is formed by applying an ultraviolet (UV) curable resin by spin coating.

  At this time, in the present embodiment, as described above, the occurrence of burrs on the disk substrate is prevented, and the step formed between the stamper 29 and the protrusion 62 can be reduced. Therefore, when applying an ultraviolet curable resin to a disk substrate, a cover layer, etc. by spin coating, air is between the disk substrate and the ultraviolet curable resin, between the cover layer and the ultraviolet curable resin, etc. It will not be caught in. Therefore, since the ultraviolet curable resin can be stably applied to the disk substrate, the cover layer, etc., it is possible to prevent the appearance of the disk substrate from being deteriorated.

  Next, a second embodiment of the present invention in which the shape of the press-fitted deformation portion is different will be described. In addition, about the thing which has the same structure as 1st Embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 5 is a cross-sectional view showing the main part of a disk-molding mold according to the second embodiment of the present invention.

  In this case, the annular protrusion 62 as the overhanging portion is an inclined line formed in a straight line from the outer peripheral edge of the flat front end surface s11 of the inner holder main body 61 obliquely rearward and radially outward. The surface s12, the cylindrical surface s3 formed from the outer peripheral edge of the inclined surface s12 toward the rear, and the rear side of the cylindrical surface s3, and obliquely rearward and radially inward. A conical inclined surface s4 is formed. The inclined surface s12 forms a tapered portion.

  In the present embodiment, since the protrusion 62 is thicker as it is closer to the center, the strength of the protrusion 62 can be increased. Therefore, the durability of the inner holder 60 can be improved.

  Next, a third embodiment of the present invention in which the shape of the press-fitted deformation portion is further different will be described. In addition, about the thing which has the same structure as 1st Embodiment, the same code | symbol is provided and the effect of the same embodiment is used about the effect of the invention by having the same structure.

  FIG. 6 is a cross-sectional view showing the main part of a disk-molding mold according to the third embodiment of the present invention.

  In this case, the annular projecting portion 62 as the projecting portion is formed linearly from the outer peripheral edge of the flat front end surface s1 of the inner holder main body 61 toward the outer side in the radial direction, and constitutes a flat end portion. A cylindrical surface s3 formed from the outer peripheral edge of the front end surface s2 toward the rear, and is formed to bend obliquely rearward and radially inward behind the cylindrical surface s3. A conical inclined surface s4 and an annular flat surface s7 formed radially inward are provided between the rear end of the cylindrical surface s3 and the front end of the inclined surface s4.

  The inclined surface s4 is formed so as to draw a predetermined curve between the point p3 on the inner peripheral edge of the plane s7 and the point p2 at the front end of the cylindrical surface s5 of the inner holder body 61, and the center of the inner holder 60 The diameter representing the distance from is continuously changed, and is larger as it is closer to the point p3 and smaller as it is closer to the point p2. The inclined surface s4 has a predetermined radius of curvature so that the tangent at the point p3 substantially coincides with the front end surface of the stamper 29 and the tangent at the point p2 coincides with the cylindrical surface s5 of the inner holder body 61. It is formed.

  At the point p1, the cylindrical surface s3 and the plane s7 are crossed at an angle of 90 [°].

  In the present embodiment, when the inner holder 60 is press-fitted into the hole of the stamper 29, if the stamper 29 is plastically deformed, the cylindrical surface s3 enters the stamper 29 by a slight amount. Thus, in the stamper 29, the cylindrical surface s3 and the plane s7 intersect at an angle of 90 °.

  Therefore, even if a slight gap is formed between the inclined surface s4 and the inner peripheral surface s6 'of the hole, the resin is prevented from entering at the portion where the cylindrical surface s3 and the flat surface s7 intersect. Generation of burrs on the substrate can be prevented. As a result, the quality of the disk substrate can be improved.

  In the present embodiment, the front end surface s2 constituting the flat portion is formed radially outward from the outer peripheral edge of the front end surface s1, and the cylindrical surface s3 is formed rearward from the outer peripheral edge of the front end surface s2. However, as in the second embodiment, an inclined surface s12 can be formed between the front end surface s11 and the cylindrical surface s13.

  The present invention is not limited to the above embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

12, 32 Mold assembly 16, 36 Mirror plate 29 Stamper 60 Inner holder 61 Inner holder body 62 Projection

Claims (9)

(A) a mirror surface board;
(B) a stamper having a hole formed in the center and attached to the front end surface of the specular disc;
(C) having an inner holder that holds the stamper by being press-fitted into the hole;
(D) The inner holder includes an inner holder main body and a protruding portion formed integrally with the inner holder main body , projecting radially outward at the outer peripheral edge of the front end of the inner holder main body ,
(E) The press-fit deformation portion set in at least one of the stamper and the inner holder is plastically deformed by the stress exceeding the yield point as the press-fitting is performed,
(F) said overhanging portion, said being protruded radially outward so as to cover the inner peripheral surface and the periphery of the hole of the stamper, as the said press-fitting is carried out, the outer of the projecting portion A disk-molding die , wherein a press-fit deformation portion is deformed radially inward from a peripheral edge, and an overhang portion covers the press-fit deformation portion .   The disk molding die according to claim 1, wherein the stamper is plastically deformed as the press-fitting is performed.   The overhanging portion includes a cylindrical surface extending in the axial direction at an outer peripheral edge, and an inclined surface formed rearwardly of the cylindrical surface, obliquely rearward, and radially inward. 2. A disk molding die according to 1.   4. The disk molding die according to claim 3, wherein the inclined surface is formed obliquely rearward from the rear end of the cylindrical surface and radially inward.   The disk molding die according to claim 3, wherein an annular flat surface is formed radially inward between a rear end of the cylindrical surface and a front end of the inclined surface. Disc molding in which an inner holder is press-fitted into a hole formed in a stamper , and as the press-fitting is performed, a press-fitted deformation portion set in at least one of the stamper and the inner holder is plastically deformed by a stress exceeding the yield point. In the inner holder of the mold,
(A) an inner holder body;
(B) On the outer peripheral edge of the front end of the inner holder main body , there is a projecting portion that is protruded radially outward and formed integrally with the inner holder main body ,
(C) The projecting portion includes a cylindrical surface extending in the axial direction at the outer peripheral edge, and an inclined surface formed obliquely rearward and radially inward behind the cylindrical surface. And projecting radially outward so as to cover the inner peripheral surface and the peripheral edge of the hole of the stamper, and in the radial inner side from the outer peripheral edge of the projecting portion as the press-fitting is performed . An inner holder characterized in that the press-fit deformation portion is deformed and the overhanging portion covers the press-fit deformation portion .   The inner holder according to claim 6, wherein a tapered portion is constituted by a front end surface of the overhang portion.   The inner holder according to claim 6, wherein a flat portion is configured by a front end surface of the overhang portion. A mirror plate, a hole formed in the center, and a stamper attached to the front end surface of the mirror plate, and an inner holder for holding the stamper, the inner holder is an inner holder main body, and an outer peripheral edge of the front end of the inner holder main body, In a manufacturing method of a disk molding die provided with a projecting portion formed integrally with the inner holder main body so as to protrude outward in the radial direction,
(A) the inner holder is press-fitted into the hole of the stamper;
(B) The press-fit deformation portion set in at least one of the stamper and the inner holder is plastically deformed by a stress exceeding the yield point as the press-fitting into the hole of the stamper of the inner holder is performed.
(C) the projecting portion, said being protruded radially outward so as to cover the inner peripheral surface and the periphery of the hole of the stamper, as the said press-fitting is carried out, the outer of the projecting portion A method for manufacturing a disk molding die , wherein a press-fitted deformation portion is deformed radially inward from a peripheral edge, and an overhanging portion covers the press-fitting deformation portion .

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