JP2007111894A - Mold assembly for molding disk substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold assembly for molding a disk substrate simple in constitution, capable of effectively holding the axis of a locking part, capable of molding the disk substrate of good quality and easily subjected to maintenance and inspection. <P>SOLUTION: In the mold assembly 10 for molding the disk substrate equipped with a first mirror surface plate 23, a stamper 22 arranged on the mirror surface of the first mirror surface plate an outer periphery holding ring 31 which holds the outer periphery of the stamper at the outer periphery of the first mirror surface plate, and a second mirror surface plate 16 having a protruded part 44 which forms a cavity 21 by fitting the inner peripheral surfaces 43 and 47 of an outer periphery holding ring in the recessed part formed using the surface of the stamper 22 as a base, a ball bearing 36 is provided to the fitting part of the recessed part and the protruded part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk substrate molding die apparatus that minimizes burrs generated at the outer peripheral edge of a disk substrate and prevents damage to a fitting portion.

  A disk substrate molding mold apparatus includes a fixed mold and a movable mold that form a cavity, a stamper that is disposed in the movable mold, and an outer periphery pressing ring that is attached to an opposing surface of the movable mold in which the stamper is disposed. The inner periphery of the outer periphery pressing ring and the outer periphery of the mirror surface formed on the opposing surface of the fixed mold enter each other and face each other when the mold is closed. A gap that communicates the inside and the outside of the cavity is formed, the cavity side portions of both fitting surfaces are formed substantially parallel to the central axis, and the anti-cavity side portion is at a predetermined angle with respect to the central axis. It forms so that it may incline (for example, refer patent document 1). And, by forming the gap on the opposite cavity side part of both fitting surfaces at a narrower interval than the gap on the cavity side part, the coaxiality between the outer periphery holding ring and both molds is shifted. However, when the mold is closed, the portion of the mating surface on the side opposite to the cavity comes into contact with the portion on the cavity side before the portion on the cavity side. The gap can be maintained without contact. Therefore, it is possible to prevent the molding of the disk substrate in which the resin material injected and filled in the cavity leaks from the gap and the burrs are generated. However, the gap between the mating surfaces on the side opposite to the cavity is formed with a narrower gap than the gap between the parts on the cavity side. there were.

Further, another disk substrate molding die apparatus includes a fixed-side mold platen, a stamper disposed on a mirror surface of the fixed-side platen, and a mirror surface outer peripheral portion of the movable mirror platen facing the fixed-side platen. A disk substrate molding die apparatus including a cavity ring that moves in a direction and holds an outer peripheral portion of the stamper to form an end face of the cavity, and the cavity ring to be fitted and a side surface of the movable mirror plate A ball retainer is provided between them to keep the clearance between them constant, and to smoothly perform the sliding operation between them (for example, see Patent Document 2). However, the ball retainer is formed by integrating the ball itself and a member for holding the ball, and the entire ball retainer must be replaced even when only a part of the balls is damaged. Further, it is not easy to replace the ball retainer itself.
JP 2001-138336 A JP 2004-74727 A (paragraph 0020, FIGS. 2 and 5)

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. For disk substrate molding, the engagement portion can be effectively cored with a simple configuration, a good quality disk substrate can be molded, and maintenance inspection can be easily performed. An object is to provide a mold apparatus.

  That is, the invention of claim 1 includes a first mirror surface plate, a stamper disposed on the mirror surface of the first mirror surface plate, and an outer peripheral holding ring that holds the outer peripheral portion of the stamper on the outer peripheral portion of the mirror surface of the first mirror surface plate. In the disk substrate molding die apparatus, the inner peripheral surface of the outer peripheral holding ring includes a second mirror surface plate having a convex portion that is fitted into a concave portion that forms the bottom surface of the stamper and forms a cavity. The present invention relates to a disk substrate molding die apparatus in which a ball bearing is provided in a fitting portion between the projection and the projection.

  According to a second aspect of the present invention, in the first aspect, the ball bearing cannot be escaped in a direction perpendicular to the central axis in a receiving groove provided at a position where the circumference of the convex side surface of the second mirror surface plate is equally divided. The present invention relates to a disk substrate molding die apparatus that is configured to be rotatable and to contain a sphere so that a part thereof protrudes.

  According to a third aspect of the present invention, the first mirror surface plate, the stamper disposed on the mirror surface of the first mirror surface plate, and the outer peripheral portion of the mirror surface of the second mirror surface plate facing the first mirror surface plate move in the central axis direction, and In a disk substrate molding die apparatus having an outer peripheral holding ring that holds an outer peripheral portion of a stamper and forms an end face of a cavity, a circumference of a convex side surface of the second mirror surface plate that is fitted to the outer peripheral holding ring is measured. In a disk substrate molding die apparatus in which a ball bearing is configured by housing a sphere so that a part of the housing groove provided in an equally divided position cannot be escaped and rotated in the direction perpendicular to the central axis and protrudes partially. Related.

According to a fourth aspect of the present invention, there is provided the disk substrate molding according to the second or third aspect, wherein the receiving groove is annular and includes a detachable partition member larger than the diameter of the sphere on one side or both sides of the sphere row. It relates to a mold apparatus.

  A fifth aspect of the present invention relates to the disk substrate molding die apparatus according to the second or third aspect, wherein the sphere has a hardness lower than a hardness of the outer peripheral holding ring.

  A sixth aspect of the present invention relates to the disk substrate molding die apparatus according to the second or third aspect, wherein a gas vent groove is provided in the vicinity of both sides of the spherical row of the accommodating groove.

  The invention of claim 1 includes a first mirror surface plate, a stamper disposed on the mirror surface of the first mirror surface plate, an outer peripheral holding ring that holds an outer peripheral portion of the stamper on a mirror outer peripheral portion of the first mirror surface plate, In the disk substrate molding die apparatus, the inner peripheral surface of the outer peripheral holding ring is provided with a second mirror surface plate having a convex portion that fits into a concave portion that forms the surface of the stamper as a bottom surface to form a cavity. A ball bearing is provided in a fitting portion with the convex portion. Therefore, the core of the engaging portion can be effectively maintained and a good quality disk substrate can be formed.

  According to a second aspect of the present invention, in the first aspect, the ball bearing cannot be escaped in a direction perpendicular to the central axis in a receiving groove provided at a position where the circumference of the convex side surface of the second mirror surface plate is equally divided. Since the sphere is accommodated so as to be rotatable and partly protrudes, the ball bearing can be configured easily and easily, and maintenance management is facilitated.

  According to a third aspect of the present invention, the first mirror surface plate, the stamper disposed on the mirror surface of the first mirror surface plate, and the outer peripheral portion of the mirror surface of the second mirror surface plate facing the first mirror surface plate move in the central axis direction, and In a disk substrate molding die apparatus having an outer peripheral holding ring that holds an outer peripheral portion of a stamper and forms an end face of a cavity, a circumference of a convex side surface of the second mirror surface plate that is fitted to the outer peripheral holding ring is measured. A ball bearing is constructed by accommodating a spherical body in an accommodation groove provided at an equally divided position so that it cannot be escaped and rotated in the direction perpendicular to the central axis, and a part of the ball protrudes. Therefore, the core of the engaging portion can be effectively maintained and a good quality disk substrate can be formed.

  According to a fourth aspect of the present invention, in the second or third aspect, the receiving groove has an annular shape and includes a detachable partition member larger than the diameter of the sphere on one side or both sides of the sphere row. The bearing can be configured simply and easily, and maintenance management is facilitated.

  According to a fifth aspect of the present invention, in the second or third aspect, since the sphere has a hardness lower than the hardness of the outer peripheral holding ring, maintenance management of the disk substrate molding die apparatus is facilitated.

  The invention of claim 6 is the invention according to claim 2 or 3, wherein gas venting grooves are provided in the vicinity of both sides of the spherical row of the accommodating grooves, so that molding defects caused by gas or the like are suppressed, and a high-quality disk substrate is obtained. Can be molded.

  Embodiments of the present invention will be described in detail with reference to the drawings. 1 is a longitudinal sectional view showing a main part of a disk substrate molding die apparatus, FIG. 2 is an enlarged sectional view showing an engaging portion of a fixed mold and a movable mold in FIG. 1, and FIG. 3 is another disk substrate. FIG. 4 is an enlarged sectional view showing an engaging portion of the molding die device, FIG. 4 is a view taken along the line AA in FIG. 2 showing the ball bearing of the present invention, and FIG. 5 is a sectional view taken along the line BB in FIG. FIG.

  A disk substrate molding apparatus 10 shown in FIG. 1 includes a fixed mold 20 and a movable mold 35. The fixed mold 20 is fixedly attached to a fixed plate of an injection molding machine (not shown) by a locate ring 11 via a heat insulating plate 12 and fixed to the mold plate 14 via a back plate 15 and protrudes from an outer peripheral portion. Mirror surface plate (second mirror surface plate) 16 having convex portions 44, gate insert 17 inserted in the central axis holes of mirror surface plate 16 and back plate 15, and inserted in the central axis holes of gate insert 17 and template 14. The sprue bush 13, the plurality of stopper blocks 19 which are erected on the template 14 and come into contact with the template 25 of the movable die 35 at the time of mold matching, and are fitted on the template 25 of the movable die 35 which are erected on the template 14. And a plurality of guide rods 18 for guiding the mold matching.

  The movable mold 35 is disposed on a mirror plate on the surface of the mirror plate 23, a back plate 24 attached to a movable plate of an injection molding machine (not shown), a mirror plate 23 fixed to the mold plate 25 via the back plate 24, and the mirror plate 23. The outer peripheral holding ring 31 that engages with the outer peripheral surface of the stamper 22, the outer peripheral portion of the mirror surface plate 23 that holds the outer peripheral portion of the stamper 22 to the outer peripheral surface of the mirror surface plate 23, and the outer peripheral holding ring 31. And a holding pin 33 that is detachably attached to and engaged with the presser ring 32 and pulled from the template 25, and further includes a central shaft hole of the mirror plate 23 and the back plate 24. The central shaft has a protruding pin 26, and a male cutter 27, a protruding sleeve 28, a fixing sleeve 29, and an inner peripheral stamper holder 30 are externally inserted in order from the protruding pin 26.

  When the movable die 35 moves toward the fixed die 20 in the direction of the central axis and is aligned, as shown in FIG. 2, the surface of the stamper 22 is the bottom, and the inner peripheral surfaces 43 and 47 of the outer peripheral holding ring 31 are the wall surfaces. The convex portion 44 of the mirror surface plate 16 is fitted into the concave portion to be formed, and the cavity 21 is formed by the mirror surface of the mirror surface plate 16, the surface of the stamper 22, the inner peripheral surface 47 of the outer peripheral holding ring 31, and the like. In the above example, the stamper 22 is disposed on the mirror surface of the movable-side mirror surface plate 23 serving as the first mirror surface plate, but the disk substrate molding die apparatus is disposed on the mirror surface of the fixed-surface-side mirror surface plate. It is also possible to configure. In that case, of course, the inner peripheral stamper holder 30, the outer peripheral holding ring 31 and the like are provided in a fixed mold, and the outer peripheral shape of the mirror surface plate is such that the mirror surface plate 16 and the mirror surface plate 23 are interchanged.

  As shown in FIG. 2, an annular housing groove 40 is formed on the convex side surface 42 of the convex portion 44 of the mirror surface board 16 that is inserted into the concave portion to form the cavity 21. The convex side surface 42 in the vicinity of the housing groove 40 is a surface parallel to the central axis. As shown in FIG. 5, the cross-sectional shape of the housing groove 40 that houses the sphere 41 is a trapezoid in which the width of the opening is smaller than the diameter of the sphere 41 and the width of the bottom is larger than the diameter of the sphere 41. Therefore, the spherical body 41 does not escape from the accommodation groove 40 in the direction perpendicular to the central axis. A plurality (ten in the embodiment) of spheres 41 are accommodated in a row at a position where the circumference of the housing groove 40 is equally divided (in the embodiment, divided into six equal parts). When the sphere 41 is accommodated in the accommodation groove 40, a part of the sphere 41 protrudes from the side surface of the convex portion by G1 (0.1 mm in the embodiment). Further, since the sphere 41 is accommodated so that a gap is formed between the inner side surfaces of the accommodation groove 40, the sphere 41 can be easily rotated while slightly rolling in the central axis direction. In addition, although the accommodation groove | channel 40 was illustrated by the cyclic | annular thing, it is good also as an independent long groove | channel long in the circumferential direction in the position which divided | segmented the convex part side surface 42 circumference of the convex part 44 of the mirror surface board 16 equally. Furthermore, the cross-sectional shape of the receiving groove 40 is exemplified by a trapezoidal shape, but if the sphere 41 cannot escape and rotate in the direction perpendicular to the central axis, it is rectangular and has a flange on the opening edge, etc. It may be.

  As shown in FIG. 4, a set screw 49 as a partition member is screwed to one side or both sides of the sphere 41 row in the receiving groove 40 so as to be perpendicular to the convex side surface 42 and buried from the convex side surface 42. Has been. Since the diameter of the set screw 49 is larger than the diameter of the sphere 41, when the set screw 49 is extracted, the sphere 41 of the accommodation groove 40 can be accommodated / extracted through the hole. When the partition member is provided only on one side of the sphere 41 row, a fixed convex portion is provided on the other side of the sphere 41 row to prevent the movement of the sphere 41. As described above, the partition member is preferably a set screw in terms of being easy to attach and detach and inexpensive, but may be a block-like member provided with other attaching and detaching / fixing means such as an elastic member.

  According to the embodiment, the sphere 41 is a metal sphere having a diameter of 2 mm. The material of the sphere 41 is stainless steel or bearing steel. If the hardness of the sphere 41 is not lower than the hardness of the outer periphery holding ring 31 engaged with the sphere 41, the expensive outer periphery holding ring 31 is damaged by the engagement with the sphere 41. Therefore, the material of the sphere 41 is preferably stainless steel having a hardness HRc 57 to 58 and a hardness lower than that of the bearing steel. As described above, the ball bearing 36 is configured by the receiving groove 40, the sphere 41, and the set screw 49, but it goes without saying that the ball bearing 36 is not limited to this configuration and a commercially available ball retainer or the like can be adopted. Yes.

  As shown in FIGS. 2 and 4, gas venting grooves 45, 45 are provided in the vicinity of both sides of the sphere 41 row. The gas vent groove 45 is formed in an arc shape on the convex side surface 42 so as to communicate with the space of the convex portion 44 rising portion of the mirror surface plate 16 from the gap G2 between the convex side surface 46 and the inner peripheral surface 47 of the outer peripheral holding ring 31. It has been trimmed. When the gas vent groove 45 is not provided, the gas vent passage cross-sectional area is such that the plurality of spheres 41 are provided in the gap G1 between the convex side surface 42 and the inner peripheral surface 43 of the outer peripheral holding ring 31, and the gap G2 is smaller than the conventional one. As a result, the amount of molten resin gas or the like generated from the cavity 21 is limited. Therefore, a gas vent groove 45 is provided to enlarge the gas vent passage cross-sectional area. According to the embodiment, the maximum depth of the gas vent groove 45 is 0.8 mm and the width is 6 mm. Note that the gas vent groove 45 may have another shape such as a rectangular cross section instead of the circular arc shape as described above.

  Next, based on FIGS. 1 and 2, the operation of the disk substrate molding die apparatus 10 during molding will be described. The movable platen of the injection molding machine is moved close to the fixed platen, and the movable die 35 is matched with the fixed die 20. The convex portion 44 of the fixed mold 20 is fitted into the concave portion of the movable mold 35 to form the cavity 21. At this time, the convex side surface 42 of the convex portion 44 is guided to the inner peripheral surface 43 of the outer peripheral holding ring 31 via the plurality of spheres 41. The outer peripheral holding ring 31 is pressed against the mirror surface plate 23 by a holding pin 33 and is engaged so as to be slightly movable in the direction perpendicular to the central axis. With this configuration, the gap G1 between the convex portion side surface 42 and the inner peripheral surface 43 is defined by the protruding amount G1 from the convex portion side surface 42 of the sphere 41, and is uniformly G1 over the entire circumference. Note that the gap G2 between the convex side surface 46 and the inner peripheral surface 47, which is provided on the cavity 21 side from the gap G1 between the convex side surface 42 and the inner peripheral surface 43 and has a prescribed thickness of the cavity 21, is larger than the gap G1. It is set small (5 μm in the embodiment). The gap G1 is provided in parallel to the central axis, whereas the gap G2 is provided so as to be narrowed and tilted slightly inward from the central axis. Therefore, although the gap G2 becomes smaller as compared with the gap G1 as the compression molding proceeds, the gap G2 can be favorably maintained without partial contact.

  At a position just before the stopper block 19 abuts the template 25, the molten resin previously plasticized and stored in the front part of the injection device is injected into the cavity 21 from an injection device (not shown) that abuts against and presses against the sprue bush 13. Eject. Thereafter, the movable mold 25 is further moved to the fixed mold 20 at an appropriate time, and the molten resin in the cavity 21 is spread and fluidized to perform compression molding. By this compression molding, the molten resin is filled into the cavity 21 and reaches the inner peripheral surface 47 of the pressing portion 48 of the outer peripheral holding ring 31. At this time, since the gap G2 is sufficiently narrow and uniform, the molten resin does not enter the gap G2, and no burrs are generated at the outer peripheral edge of the disk substrate. Even if the molten resin slightly enters the gap G2 and becomes burrs, it is uniform and does not change the weight distribution of the disk substrate. There is no problem.

  The fitting between the concave portion and the convex portion 44 at the time of compression molding is performed by moving in the range of about several hundred microns in the central axis direction, but there is a gap between the spherical body 41 and the inner side surfaces of the receiving groove 40. Since it is provided, the spherical body 41 can be rotated very easily and smoothly during compression molding, and compression molding can be executed effectively.

  The molten resin filled in the cavity 21 starts to be cooled immediately. At an appropriate point in the process, the male cutter 27 moves forward, and the male cutter 27 is fitted into the recess formed by the end face of the sprue bush 13 in the central hole of the gate insert 17, thereby opening the central opening of the disk substrate in the cavity 21. Perforated. Thereafter, the movable die 35 is separated from the fixed die 20, and the disc substrate is released from the mirror surface plate 16 and is held by the stamper 22 to open the die. Further, the gate-cut sprue is held at the tip of the protruding pin 26 and the mold is opened. After the mold is opened, the protruding pin 26 is first moved forward to protrude the sprue, and the protruding sleeve 28 is moved forward after a while, and the disk substrate having the perforated center opening is protruded and taken out.

  Next, another disk substrate molding die apparatus 50 will be described with reference to FIG. The other disk substrate molding die device 50 includes a mirror surface plate 51, a mirror surface plate 56, and an outer peripheral holding ring 55 that correspond to the mirror surface plate 16, the mirror surface plate 23, and the outer peripheral holding ring 31 of the disk substrate molding die device 10. The other members are the same as those of the disk substrate molding die apparatus 10. Therefore, the other disk substrate molding apparatus 50 is exemplified as the stamper 22 disposed on the mirror plate 51 on the fixed mold side, but the stamper 22 is movable as in the case of the disk substrate molding apparatus 10. It can also be set as the structure arrange | positioned at the type | mold side.

  The movable-type mirror surface plate 56 has a large step portion on the outer periphery, and an inner side of the step portion has a convex portion 62 protruding toward the fixed-type side mirror surface plate 51. The convex portion 62 is further provided with a small step portion, and the side surface of the convex portion 62 has a convex portion side surface 58 positioned between the large step portion and the small step portion, and a convex portion adjacent to the mirror surface that is the end surface of the convex portion 62. It is divided into partial side surfaces 60. A ball bearing 36 is provided on the convex side surface 58.

  An outer peripheral holding ring 55 having inner peripheral surfaces 59 and 61 facing the convex side surfaces 58 and 60 is fitted on the outer periphery of the convex portion 62 so as to be movable in the central axis direction. The gap between the convex side surface 58 and the inner peripheral surface 59 is maintained at the gap G <b> 1 by the ball bearing 36. Further, the gap between the convex side surface 60 and the inner peripheral surface 61 is maintained at a gap G2 that is smaller than the gap G1. The outer peripheral holding ring 55 is always urged in the direction of the central axis from the surface of the large step portion of the specular disk 56 by a protruding mechanism 57 such as a resilient member. The surface opposite to the surface urged by the protruding mechanism 57 of the outer peripheral holding ring 55 is provided with a double annular convex portion. The outer annular convex portion presses the mirror surface plate 51 via the abutment ring 52, and the inner annular convex portion lower than the outer annular convex portion serves as a holding portion 53, and the stamper 22 is moved to the mirror surface plate 51 with a slight gap. Hold on a mirror surface.

  The operation of the other disk substrate molding die device 50 is different from the operation of the disk substrate molding die device 10 because the outer peripheral holding ring 55 is different from the outer peripheral holding ring 31 of the disk substrate molding die device 10. That is, the annular convex portion outside the outer periphery holding ring 55 contacts the mirror surface plate 51 to form the cavity 54 before the molten resin is injected at the initial stage of mold matching. Then, the convex portion 62 of the mirror surface plate 56 engages with the inner peripheral surfaces 59 and 61 of the outer peripheral holding ring 55 via the ball bearings 36, and the movable mold further moves closer to the fixed mold. When the cavity 54 reaches a predetermined volume, molten resin is injected, and the movable mold is further moved closer to the fixed mold to perform compression molding. At this time, since the gap G2 is sufficiently narrow and uniformly formed by the ball bearings 36, the molten resin does not enter the gap G2, and burrs are not generated at the outer peripheral edge of the disk substrate. Even if the molten resin slightly enters the gap G2 and becomes burrs, it is uniform and does not change the weight distribution of the disk substrate. There is no problem. In addition, the outer periphery holding ring 55 and the convex portion 62 are fitted to each other at the time of compression molding by moving within the range of several hundred microns in the central axis direction. Since a gap is provided between them, the sphere 41 can be rotated very easily and smoothly during compression molding, and compression molding can be executed effectively. In addition, since the process after compression molding is the same as that of the case of the disk substrate molding die apparatus 10, description is abbreviate | omitted.

  The present invention includes those that can be implemented in variously modified, modified, improved, and other forms based on the knowledge of those skilled in the art. Further, it goes without saying that any of the embodiments to which the above-mentioned changes are added is included in the scope of the present invention without departing from the gist of the present invention.

It is a longitudinal cross-sectional view which shows the principal part of a disk substrate shaping die apparatus. It is an expanded sectional view which shows the fixed type | mold and movable type engaging part in FIG. It is an expanded sectional view which shows the engaging part of another disk substrate shaping die apparatus. It is an AA arrow line view in FIG. 2 which shows the ball bearing of this invention. It is a BB arrow sectional view in Drawing 4.

Explanation of symbols

10, 50 Disc substrate molding die device 16, 23, 51, 56 Mirror plate 21 Cavity (concave)
22 stamper 31, 55 outer periphery holding ring 36 ball bearing 40 receiving groove 41 sphere 42, 46, 58, 60 convex side surface 43, 47, 59, 61 inner peripheral surface 44, 62 convex portion 45 degassing groove 49 set screw 54 cavity G1, G2 gap

Claims (6)

A first mirror surface plate, a stamper disposed on a mirror surface of the first mirror surface plate, an outer peripheral holding ring for holding an outer peripheral portion of the stamper on a mirror outer peripheral portion of the first mirror surface plate, and an inner peripheral surface of the outer peripheral holding ring In a disk substrate molding die apparatus comprising a second mirror surface plate having a convex portion that is fitted into a concave portion that forms the surface of the stamper as a bottom surface to form a cavity,
A disk substrate molding die apparatus, wherein a ball bearing is provided at a fitting portion between the concave portion and the convex portion.   The ball bearing is not allowed to escape in the direction perpendicular to the central axis and is rotatable, and a part of the ball bearing protrudes into a receiving groove provided at a position obtained by equally dividing the circumference of the convex side surface of the second mirror surface plate. 2. The disk substrate molding die apparatus according to claim 1, wherein a spherical body is accommodated in the disk substrate molding die apparatus. The first mirror surface plate, the stamper disposed on the mirror surface of the first mirror surface plate, and the mirror surface outer peripheral portion of the second mirror surface plate facing the first mirror surface plate move in the central axis direction to hold the outer periphery of the stamper. In the disk substrate molding die apparatus provided with an outer peripheral holding ring that forms the end face of the cavity,
A receiving groove provided at a position that equally divides the circumference of the convex side surface of the second mirror surface plate that fits with the outer peripheral holding ring cannot partially escape in the direction perpendicular to the central axis and is rotatable, and a part thereof A disk substrate molding die apparatus characterized in that a ball bearing is formed by accommodating a sphere so as to protrude.   4. The disk substrate molding die device according to claim 2, wherein the receiving groove has an annular shape and has a detachable partition member larger than the diameter of the sphere on one side or both sides of the sphere row.   4. The disk substrate molding die apparatus according to claim 2, wherein the sphere has a hardness lower than that of the outer peripheral holding ring. The disk substrate molding die apparatus according to claim 2 or 3, wherein a gas vent groove is provided in the vicinity of both sides of the spherical body row of the housing groove.

Images