JP2017140798A - Nest for lens molding die and lens molding die therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nest for a lens molding die capable of adjusting a thickness of a plastic lens that is a molded product simply and with accuracy and a lens molding die therewith.SOLUTION: A nest of a lens molding die that includes a first nest having a recess part provided with a through-hole on a bottom surface and a second nest engaged with the recess part of the first nest, in which, when an end surface on the bottom surface side in the recess part is assumed as a front end surface and an end surface on the opposite side thereof is assumed as a back end surface, the front end surface of the second nest has a lens molding part that is a projection part engaged with the through hole of the recess part and a flat surface part that is a flat surface facing a bottom surface of the recess part, between the bottom surface of the recess part and the flat surface part of the second nest, a first elastic member is placed, and the lens molding die provided therewith are used to solve the problem.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a lens mold nest and a lens mold having the same.

  Patent Document 1 listed below discloses a mold that can adjust the thickness of a lens that is a molded product by compressing and deforming an elastically deformable spacer member with a screw.

JP 2007-125809 A

  In order to increase the molding accuracy of the plastic injection mold, it is necessary to keep the tolerances of the parts constituting the mold as small as possible. In particular, in a nesting mold, it is necessary to fix the nesting so that an error does not occur in the nesting position due to the clearance provided in the nesting housing portion. Furthermore, with the recent increase in resolution of imaging lens units (such as in-vehicle cameras and surveillance cameras), mold precision for micrometer units is required for molds used to mold plastic lenses. It is difficult to achieve this mold accuracy simply by suppressing the tolerance of each part. For this reason, it is desirable that the mold for plastic lens molding be provided with a mechanism capable of finely adjusting the relative positions of the movable side and fixed side opposing surfaces that define the lens molding portion.

  Furthermore, in order to realize the optical characteristics required for the plastic lens, it is desirable to have a mechanism capable of removing not only the lens eccentricity but also its thickness error.

  In view of the above-described problems, the problem to be solved by the present invention is to provide a lens molding die nesting capable of easily and accurately adjusting the thickness of a plastic lens as a molded product, and a lens molding die including the same. It is to provide.

  In order to solve the above-described problems, the lens mold mold according to the present invention includes a first insert having a recess having a through hole on the bottom surface, and a second insert fitted into the recess of the first insert. And when the end surface of the second nesting on the bottom surface side of the recess is a front end surface and the end surface on the opposite side is the rear end surface, the front end surface of the second nesting is A lens molding portion that is a protruding portion fitted in the through hole, and a flat surface portion that is a flat surface facing the bottom surface of the concave portion, and the bottom surface of the concave portion and the flat surface portion of the second nesting A first elastic member is disposed between the first elastic members.

  Since the first elastic member is disposed between the bottom surface of the recess of the first insert and the flat portion of the second insert, the second insert is always pressed against the opening side of the recess by receiving the repulsive force of the first elastic member. Will be. The lens mold nest according to the present invention includes the first elastic member, so that when the lens thickness is finely adjusted, the position of the second nest in the depth direction of the recess is easily changed. be able to. Further, it is possible to prevent galling of the bottom surface of the recess and the flat surface portion of the second nesting, thereby extending the nesting life.

  Moreover, it is preferable that the spacer member which contact | abuts to the said rear-end surface of a said 2nd nesting is fitted by the opening side of the said recessed part rather than the said 2nd nesting in the said recessed part.

  When the spacer member is not disposed on the rear end face side of the second nesting, it is necessary to change the length of the second nesting itself in the depth direction of the recess when finely adjusting the thickness of the lens. The lens mold nesting of this configuration is appropriately changed in the thickness of the spacer member without changing the length of the second nesting itself by arranging the spacer member on the rear end surface side of the second nesting. This makes it possible to finely adjust the thickness of the lens.

  The first elastic member is preferably an O-ring.

  O-rings of various standards are generally distributed in the market, and those having the optimum shape and properties can be easily obtained.

  The second insert has a cylindrical body portion, and a groove portion is formed along the circumferential direction on the outer surface of the main body portion, and an O-ring that is a second elastic member is formed in the groove portion. Is preferably attached.

  When the O-ring which is the second elastic member is attached to the body portion of the second nesting, the contact surface between the concave portion of the first nesting and the body portion of the second nesting is generated when the second nesting is attached / detached. Can be prevented. Moreover, it is necessary to provide a clearance for fitting the second insert in the recess, and there is a possibility that an error corresponding to the clearance may occur at the position of the second insert fitted in the recess. The nesting for a lens molding die of this configuration is capable of reducing such an error by mounting an O-ring as a second elastic member on the body of the second nesting.

  Moreover, it is preferable that the opening edge of the groove is provided with a radius.

  When the opening edge of the groove has a sharp corner, the second elastic member may be twisted or bitten when the second insert is fitted into the recess of the first insert. Providing a radius at the opening edge of the groove can suppress such a problem.

  Further, an air hole penetrating from the inner peripheral surface to the outside of the first nest is provided on the inner peripheral surface in the vicinity of the bottom surface of the concave portion, and the first elastic member is formed in a part of the circumferential direction. Preferably, the first elastic member is arranged in a direction in which the cutout portion communicates with the air hole.

  Since the cutout portion of the first elastic member and the air hole of the first nest are in communication, the air in the recess can escape from the air hole when the second nest is fitted into the recess of the first nest. This makes it possible to more easily fit the second nest.

  In order to solve the above-mentioned problems, a lens molding die according to the present invention is characterized by including a movable side mold plate and a fixed side mold plate having a nesting for the lens molding die.

  By using the nest for a lens molding die of the present invention as a nest for molding both surfaces of the lens, it becomes possible to further increase the thickness accuracy of the lens.

  According to the insert for a lens molding die and the lens molding die provided with the same according to the present invention, it is possible to easily and accurately adjust the thickness of a plastic lens as a molded product.

It is a schematic diagram which shows the whole structure of an injection molding machine provided with the metal mold | die for lens shaping | molding concerning embodiment. It is a top view which shows the parting surface of a stationary-side template. It is a top view which shows the parting surface of a movable side template. FIG. 3 is an enlarged view of a fixed side nesting surrounded by a broken line A in FIG. 2. It is AA sectional drawing of FIG. It is side surface sectional drawing which shows the joining state of the fixed side nest and the movable side nest when the lens mold is closed.

<Outline of mold configuration>
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a lens molding die and a lens molding die having the same according to the present invention will be described in detail with reference to the drawings. The lens molding die 910 in this embodiment is an example of a multi-cavity mold for molding a plastic lens used in an imaging system lens unit.

  FIG. 1 is a schematic diagram showing an overall configuration of an injection molding machine 900 including a lens molding die 910 of the present embodiment. The lens molding die 910 is mounted on the injection molding machine 900 with its fixed side mounting plate 912 attached to the stationary platen 921 of the injection molding machine 900 and the movable side mounting plate 914 attached to the movable board 922. The injection molding machine 900 opens and closes a movable side mold plate 915 that is a mold plate and a fixed side mold plate 913 that is a mold plate by a parting line PL to mold and take out a molded product. The type of the injection molding machine 900 is not limited as long as it is a molding machine capable of performing a general plastic injection molding operation.

  FIG. 2 is a plan view showing the parting surface 913a of the fixed side template 913. FIG. On the parting surface 913a, twelve fixed-side core housing portions 410 are formed at equal intervals in the circumferential direction with the center of the parting surface 913a as the center. Each fixed-side core housing portion 410 has a substantially quadrangular prism shape. The fixed core 100 (nesting) is fitted. For convenience of explanation, in FIG. 2, description of various pins and pin holes used for positioning, connection, guides, or the like of the members constituting the lens molding die 910 is omitted.

  Each fixed-side core accommodating portion 410 accommodates wedge-shaped spacers 310 and 320, which will be described later, together with the fixed-side core 100. Each fixed-side core 100 is arranged in the fixed-side core accommodating portion 410 by the wedge-shaped spacers 310 and 320. The position is fixed. A lens molding portion 121 having a convex lens molding surface 121a extends from the center of the parting surface 100e of each fixed-side core 100.

  On the parting surface 913a of the fixed-side template 913, a fixed-side runner half 510, which is six grooves extending radially from the sprue runner 550 provided at the center in the plane direction, is formed. Each of these fixed-side runner halves 510 is further bifurcated and extends to the parting surface 100e of each fixed-side core 100.

  FIG. 3 is a plan view showing the parting surface 915 a of the movable side template 915. As with the parting surface 913a of the fixed-side template 913, twelve movable-side core accommodating portions 420 are formed at equal intervals in the circumferential direction around the center of the parting surface 915a. Each movable side core accommodating portion 420 is fitted with a substantially prismatic movable side core 200 (nested). In FIG. 3, as in FIG. 2, the description of various pins and pin holes used for positioning, connection, guides, or the like of the members constituting the lens molding die 910 is omitted.

  Each movable-side core accommodating portion 420 accommodates the wedge-shaped spacers 310 and 320 together with the movable-side core 200, and each movable-side core 200 has its arrangement position in the movable-side core accommodating portion 420 fixed by the wedge-shaped spacers 310 and 320. Has been. At the center of the parting surface 200e of each movable core 200, a lens molding portion 221 having a concave lens molding surface 221a is exposed.

  On the parting surface 915a of the movable side template 915, there are formed movable side runner halves 520 that are six grooves extending radially from the center in the plane direction. Each of these movable side runner halves 520 is further branched into two branches and extends to the lens molding surface 221a of each movable side core 200.

  Each fixed-side core 100 and each movable-side core 200 are arranged at positions facing each other, and form a lens molding chamber 916, which will be described later, when the lens molding die 910 is closed. . Similarly, the fixed-side runner half 510 and the movable-side runner half 520 are also arranged at positions corresponding to each other, and the lens molding die 910 is closed, so that the sprue runner 550 enters the lens molding chamber 916. A runner that guides the molten resin is formed.

<Nesting fixing structure>
4 is an enlarged view of the fixed-side core 100 surrounded by a broken line A in FIG. 5 is a cross-sectional view taken along the line AA in FIG. Hereinafter, the fixing structure of the fixed core 100 fitted mainly to the fixed core accommodating part 410 will be described. The features and fixing structures of the members shown below are fitted to the movable core accommodating part 420. The same applies to the movable core 200.

(Core configuration)
The fixed-side core 100 is a substantially quadrangular prism-shaped member whose corners in the circumferential direction of its outer peripheral surfaces (side surfaces 100a, 100b, 100c, 100d) are chamfered. The fixed-side core 100 housed in the fixed-side core housing part 410 is arranged in such a direction that its outer peripheral surface (side surfaces 100a, 100b, 100c, 100d) faces the inner peripheral surface of the fixed-side core housing part 410. The surface position of the parting surface 100e of the fixed-side core 100 is aligned with the parting surface 913a of the fixed-side template 913.

  On the side surface 100a side of the stationary side core 100 accommodated in the stationary side core accommodating portion 410, a wedge-shaped spacer 310 is disposed at a position in contact with the side surface 100a, and on the side surface 100b side, a wedge-shaped spacer is disposed at a position in contact with the side surface 100b. 320 is arranged.

  The contact portion of the side surface 100a of the fixed-side core 100 with the wedge-shaped spacer 310 is a core side contact that is an inclined surface projecting toward the wedge-shaped spacer 310 side from the opening 410f side of the fixed-side core housing portion 410 toward the bottom surface 410e side. A contact surface 101 is formed. The core-side contact surface 101 in the present embodiment is about 1/3 of the entire length of the side surface 100a in the width direction when the direction orthogonal to the height direction (Z direction) of the side surface 100a is the width direction of the side surface 100a. The width is assumed. The core-side contact surface 101 is formed to be depressed so that the surface of the side surface 100a is cut out.

  Similarly, the contact portion with the wedge-shaped spacer 320 on the side surface 100b of the fixed-side core 100 is also an inclined surface projecting toward the wedge-shaped spacer 320 from the opening 410f side of the fixed-side core housing portion 410 toward the bottom surface 410e. A core-side contact surface 102 is provided. The core-side contact surface 102 also has a width of about 1/3 of the entire length in the width direction of the side surface 100b when the direction orthogonal to the height direction of the side surface 100b is the width direction of the side surface 100b. It is formed so as to be depressed so that the surface of 100b is cut out.

  Of the outer peripheral surfaces (side surfaces 100a, 100b, 100c, and 100d) of the fixed-side core 100, the side surface is parallel to the side surface 100a pressed by the wedge-shaped spacer 310, that is, the back surface of the side surface 100a. An annular groove 103 is formed on the side surface 100c. An O-ring 181 is attached to the groove 103. The O-ring 181 is sandwiched between the side surface 100c and the side surface 410c that is a surface facing the side surface 100c among the inner peripheral surfaces of the fixed-side core housing portion 410.

  The O-ring 181 is disposed so that the center of its inner diameter overlaps with the approximate center of the side surface 100c. Further, the wedge-shaped spacer 310 is also disposed at a position where it comes into contact with the center of the side surface 100a in the width direction. Thereby, the inclination of the stationary side core 100 by the stationary side core 100 being pressed by the wedge-shaped spacer 310 is prevented.

  Similarly, the wedge-shaped spacer 320 is also arranged at a position where it comes into contact with the center of the side surface 100b in the width direction. An annular groove 104 is formed on the side surface 100b pressed by the wedge-shaped spacer 320 and in the side surface parallel to the plane direction, that is, the side surface 100d which is the back surface of the side surface 100b. An O-ring 182 is attached to the groove portion 104 so that the center in the radial direction and the approximate center of the side surface 100b overlap. The O-ring 182 is sandwiched between the side surface 100d and the side surface 410d facing the side surface 100d.

  Similarly, the O-ring 182 is arranged so that the center of its inner diameter overlaps with the approximate center of the side surface 100d. Further, the wedge-shaped spacer 320 is also disposed at a position where it comes into contact with the center of the side surface 100b in the width direction. Thereby, the inclination of the stationary side core 100 by the stationary side core 100 being pressed by the wedge-shaped spacer 320 is prevented.

  Further, the fixed side core 100 and the fixed side core housing portion 410 are exposed to corrosive gas at the time of lens molding, so that the contact surfaces are likely to be galling. In the lens molding die 910 of the present embodiment, O-rings 181 and 182 are interposed between the fixed side core 100 and the inner peripheral surface of the fixed side core housing portion 410 against which the fixed side core 100 is pressed. Thus, galling during the attachment and detachment of the fixed core 100 is suppressed.

(Configuration of nesting housing)
The fixed-side core housing portion 410 is a recess formed in the parting surface 913a of the fixed-side template 913. The inner peripheral surface of the fixed-side core housing portion 410 has side surfaces 410a, 410b, 410c, and 410d that are flat surfaces. Each of these side surfaces 410a, 410b, 410c, 410d forms a substantially quadrangular prism-shaped space in which the fixed side core 100 is fitted along the outer peripheral surface (side surfaces 100a, 100b, 100c, 100d) of the fixed side core 100. ing.

  Of the side surfaces 410a, 410b, 410c, and 410d of the fixed-side core housing portion 410, the direction perpendicular to the depth direction (Z direction) of the side surfaces 410a and 410b is the width direction of the side surfaces 410a and 410b. In the center in the width direction of the side surfaces 410a and 410b, spacer arrangement portions 411 and 412 are formed, which are spaces in which the surface positions of the side surfaces 410a and 410b are recessed stepwise. The spacer arrangement portions 411 and 412 have a width of about １ ／ of the total length in the width direction of the side surfaces 410a and 410b, and extend in the depth direction from the opening 410f of the fixed-side core housing portion 410. The spacer arrangement portions 411 and 412 are a minimum space in which the wedge-shaped spacers 310 and 320 can be arranged.

  Further, when the fixed-side core accommodating portion 410 is viewed from the opening 410f side (that is, when viewed in the line-of-sight direction in FIG. 4), each of the side surfaces 410a and 410b among the inner peripheral surface of the fixed-side core accommodating portion 410. , 410c, 410d, an extended portion 410g is formed so that the space bulges outward. Similarly, extended portions 410h that are extended so that the space bulges outward are also formed at the ends of the spacer arrangement portions 411 and 412 on the extending direction side. A gap is provided between the wall surfaces of the extended portions 410g and 410h and the fixed core 100 and the wedge-shaped spacers 310 and 320.

(Configuration of spacer member)
The wedge-shaped spacers 310 and 320 are rod-shaped members that extend in the depth direction of the fixed-side core housing portion 410. The wedge-shaped spacer 310 is a substantially quadrangular prism-shaped member, and the spacer-side contact surface 311 that is the contact portion with the side surface 100 a of the fixed-side core 100 is the inclination angle of the core-side contact surface 101. It is comprised by the plane inclined along. The surface on the opposite side of the spacer-side contact surface 311 has a shape in which the corners in the circumferential direction of the wedge-shaped spacer 310 are deeply chamfered.

  The wedge-shaped spacer 310 is provided with a through hole 313 extending in the depth direction of the spacer arrangement portion 411, and the wedge-shaped spacer 310 is fastened to the spacer arrangement portion 411 by a bolt 315 inserted through the through hole 313.

  A female thread 313 a having an inner diameter larger than the outer diameter of the shaft portion of the bolt 315 is formed on the inner peripheral surface of the through hole 313. The bolt hole for fixing the wedge-shaped spacer 310 and the female screw 313a for extracting the wedge-shaped spacer 310 are concentrated in one through hole 313, so that an increase in the number of parts is suppressed.

  A steel material having a hardness of 50 to 54 HRC is used as the material of the fixed core 100 of the present embodiment, and a steel material having a hardness higher than the hardness of the fixed core 100 is used as the material of the wedge-shaped spacer 310. Yes. When the wedge-shaped spacer 310 is made the minimum necessary size in order to reduce the size of the spacer arrangement portion 411, there is a concern that the wedge-shaped spacer 310 is likely to be deformed or distorted. In this embodiment, since the wedge-shaped spacer 310 is made of a steel material having a hardness higher than the hardness of the fixed-side core 100, deformation and distortion of the wedge-shaped spacer 310 due to repeated attachment and detachment are suppressed.

  The wedge-shaped spacer 320 fastened to the spacer arranging portion 412 with the bolt 325 also has the same shape and structure as the wedge-shaped spacer 310, and the spacer-side contact surface 321 that is the contact portion with the side surface 100b is also the core. The side contact surface 102 is constituted by a plane inclined along the inclination angle.

(Nesting positioning structure)
Abutting portions (spacer side abutting surface 311 and core side abutting surface 101, spacer side abutting surface 321 and core side abutting surface 102) of fixed side core 100 and wedge-shaped spacers 310 and 320 of this embodiment Is configured by an inclined surface that is inclined in the depth direction of the fixed-side core housing portion 410. Further, the inclination angle of the inclined surface is such that when the wedge-shaped spacers 310 and 320 are pushed down in the depth direction of the fixed-side core housing portion 410, the wedge-shaped spacers 310 and 320 push the fixed-side core 100 to the side surface of the fixed-side core housing portion 410. The angle is set to 410c, the side surface 410d, and the bottom surface 410e. As a result, even if the spacer arrangement portions 411 and 412 are narrow spaces having substantially the same size as the wedge-shaped spacers 310 and 320, the fixed-side core 100 can be used by utilizing the depth of the fixed-side core housing portion 410. It is possible to position the fixed-side core housing portion 410 at one place.

  In addition, since the outer shape of the fixed-side core 100 is not a columnar shape but a substantially prismatic shape, the wedge-shaped spacers 310 and 320 can easily grasp the side surface of the fixed-side core 100, and the fixed-side core 100 is always in a fixed direction. It is possible to press Moreover, since the circumferential position of the fixed side core 100 in the fixed side core housing portion 410 is fixed by the side surfaces 410a, 410b, 410c, and 410d of the fixed side core 100, the reproducibility of positioning of the fixed side core 100 is improved. It is done.

  In the present embodiment, two orthogonal surfaces (side surface 100a and side surface 100b) of the outer peripheral surface (side surfaces 100a, 100b, 100c, 100d) of the fixed side core 100 are pressed by wedge-shaped spacers 310, 320. The fixed-side core 100 can be positioned at one location on the fixed-side core housing 410, but depending on the molding accuracy required for the molded product and the allowable cost, It is good also as a structure which presses only. Further, although the fixed-side core 100 of the present embodiment has a substantially quadrangular prism shape, a spacer member is disposed on each of two side surfaces whose plane directions are not parallel to each other even if the fixed side core 100 has another prismatic shape. As a result, it is possible to obtain the same effect as the present embodiment.

  In this embodiment, the bolts 315 and 325 for fixing the wedge-shaped spacers 310 and 320 are always tightened to the same position. Therefore, when adjusting the strength with which the fixed core 100 is pressed by the wedge-shaped spacers 310 and 320, the length of the wedge-shaped spacers 310 and 320 itself (in the Z direction) is not adjusted, but the tightening of the bolts 315 and 325 is not adjusted. Length) is processed or replaced with another wedge-shaped spacer 310 having a different length.

  Further, it is sandwiched between the side surfaces 100c and 100d, which are the back surfaces of the side surfaces 100a and 100b pressed against the wedge-shaped spacers 310 and 320, and the side surfaces 410c and 410d of the fixed-side core housing portion 410 facing them. The O-rings 181 and 182 always push the fixed-side core 100 back toward the wedge-shaped spacers 310 and 320 by the repulsive force. Therefore, it is possible to adjust the position of the fixed core 100 in the fixed core housing 410 by simply changing the lengths of the wedge-shaped spacers 310 and 320 as appropriate. As a result, the relative positions of the fixed core 100 and the movable core 200 can be matched with high accuracy, and the eccentricity of the lens can be removed. In the lens molding die 910 of the present embodiment, the positioning structure is mounted on both the fixed side core 100 and the movable side core 200. However, the positioning structure is mounted only on one of them. May be.

<Lens thickness adjustment structure>
Hereinafter, the lens thickness adjustment structure in the lens molding die 910 of the present embodiment will be described. FIG. 6 is a side sectional view showing a joined state of the fixed side core 100 and the movable side core 200 when the lens molding die 910 is closed. The fixed side core 100 and the movable side core 200 of the present embodiment have a multiple nesting structure in which the second nestings 120 and 220 are fitted in the first nestings 110 and 210, respectively.

  The fixed core 100 and the movable core 200 form a lens molding chamber 916 by the lens molding surfaces 121a and 221a and the parting surfaces 913a and 915a. The lens molding surface 121a of the fixed core 100 forms a concave surface that is a lens surface on one side of the lens, and the lens molding surface 221a of the movable core 200 forms a convex surface that is a lens surface on the other side of the lens. A flange portion is formed by the parting surfaces 913 a and 915 a of the fixed core 100 and the movable core 200 on the outer edge of the lens to be molded. The thickness of the lens molded by the lens molding die 910 can be adjusted by moving the surface positions of these lens molding surfaces 121a and 221a. The shapes of the lens molding surfaces 121a and 221a are not limited to those of the present embodiment, and can be appropriately changed according to the shape of the lens surface to be molded (a combination of convex and convex lenses or a combination of concave and concave lenses may be used). Good). The shape of the lens surface may be an aspherical surface instead of a spherical surface.

  Hereinafter, the lens thickness adjusting structure in the fixed-side core 100 will be described with reference to FIG. The fixed core 100 of the present embodiment is configured by a combination of a first nest 110 and a second nest 120 fitted to the first nest 110. The first nest 110 has a recess 111 into which the second nest 112 is fitted. The recess 111 is a substantially cylindrical space formed by the opening 111a, the inner peripheral surface 111b, and the bottom surface 111c. The opening 111 a of the recess 111 is provided on the bottom surface 100 f of the fixed core 100. A circular through hole 112 is formed in the center of the bottom surface 111 c of the recess 111.

  Of the end faces of the second insert 112 fitted in the recess 111 of the first insert 110, the end face on the bottom face 111c side of the recess 111 is the front end face 120a, and the end face on the opposite side is the rear end face 120b. The front end surface 120a of the nest 120 is configured by a lens molding portion 121 that is a substantially cylindrical protruding portion fitted in the through hole 112 of the recess 111, and a flat portion 122 that is a plane facing the bottom surface 111c of the recess 111. Has been. A lens molding surface 121 a made of a hemispherical convex surface is formed at the tip of the lens molding portion 121. The lens molding portion 121 extends vertically from the center of the flat surface portion 122, and a tapered portion 121b whose outer peripheral surface is enlarged in a tapered shape is formed at the base end portion of the lens molding portion 121. The second nest 112 has a substantially cylindrical body portion 120c. The outer surface of the body portion 120c has a predetermined interval in the height direction (Z direction) along the circumferential direction thereof. Two groove portions 123 are formed. The body portion 120c is formed with a screw hole 124 having an opening provided in the rear end surface 120b of the second insert 120. The screw hole 124 is a hole into which a tool provided with a male screw is screwed when the second insert 120 is pulled out from the recess 111.

  In the fixed core 100 of the present embodiment, an O-ring 130 that is a first elastic member is disposed between the bottom surface 111 c of the recess 111 of the first insert 110 and the flat surface portion 122 of the second insert 120. In addition, O-rings 140 as second elastic members are mounted in the respective groove portions 123 of the second insert 120.

  Further, the opening edge 123a of each groove 123 is provided with a radius. For example, when the opening edge 123a of the groove 123 has a sharp corner, the O-ring 140 may be twisted or bitten when the second insert 120 is attached to or detached from the recess 111 of the first insert 110. In the fixed-side core 100 of the present embodiment, such a problem is suppressed by the rounds provided at the opening edge portion 123a of the groove portion 123.

  In the recess 111 of the first insert 110, a metal annular annular spacer 151 that is a spacer member that contacts the rear end surface 120 b of the second insert 120 is located closer to the opening 111 a of the recess 111 than the second insert 120. Is fitted.

  In the fixed-side core 100 of the present embodiment, the O-ring 130 is disposed between the bottom surface 111c of the recess 111 of the first insert 110 and the flat surface portion 122 of the second insert 120. Due to the repulsive force of the O-ring 130, the recess 111 is always pressed toward the opening 111a. For example, when a metal spacer member is disposed in place of the O-ring 130, the position of the lens molding portion 121 of the second nest 120 (depth direction of the recess 111 (Z direction)) to finely adjust the lens thickness. When changing the position of the second nesting 120), it is necessary to process or replace the spacer member each time. Furthermore, in the fixed side core 100 of the present embodiment, since the annular spacer 151 is separately arranged on the rear end surface 120b side of the second insert 120, it is necessary to process or replace both spacer members each time. It takes a lot of man-hours to adjust the position of the portion 121. Since the fixed-side core 100 of this embodiment includes the O-ring 130 and the annular spacer 151, when the lens thickness is finely adjusted, the annular spacer 151 is simply processed or replaced with a different thickness. It's okay. Further, the O-ring 130 prevents galling of the bottom surface 111c of the recess 111 and the flat surface portion 122 of the second insert 120, and contributes to extending the life of the insert.

  For example, when a coil spring is used instead of the O-ring 130, it is necessary to provide the lens molding portion 121 as long as the length of the coil spring in the axial direction in order to ensure the arrangement area of the coil spring. Such a configuration hinders downsizing of the fixed-side core 100 and becomes weak in strength due to an increase in the narrow diameter portion of the second insert 120. The fixed-side core 100 of the present embodiment employs the O-ring 130 as the first elastic member of the present invention, thereby reducing the size of the fixed-side core 100 and impairing the strength of the second nest 120. It is possible to adjust the lens thickness without any problem.

  In addition, since the second nest 112 of the present embodiment has two O-rings 140 attached to the body portion 120c, when the second nest 112 is attached and detached, the concave portion 111 of the first nest 110 and the second nest 112 are provided. The galling of the contact surface with the body portion 120c is suppressed. Moreover, since it is necessary to provide the clearance for fitting the 2nd nest | insert 112 in the recessed part 111, there exists a possibility that the error for the clearance may arise in the position of the 2nd nest | insert 112 fitted in the recessed part 111. There is. In the second nesting 112 of the present embodiment, the clearance is filled by the two O-rings 140 attached to the trunk portion 120c, and misalignment due to an error is prevented.

  An air hole 113 penetrating from the inner peripheral surface to the outside of the first insert 110 is provided on the inner peripheral surface in the vicinity of the bottom surface 111 c of the recess 111 of the first insert 110. The O-ring 130 of the present embodiment is provided with a notch 130a in a part of the circumferential direction, and the O-ring 130 is arranged in a direction in which the notch 130a and the air hole 113 are communicated. Thereby, when fitting the 2nd nest | insert 120 in the recessed part 111, the air in the recessed part 111 can escape from the air hole 113, and it is made possible to fit the 2nd nest | insert 120 more easily. .

  The multiple nesting structure of the fixed side core 100 is also adopted for the movable side core 200. As shown in FIG. 6, the structural differences between the fixed core 100 and the movable core 200 are as follows. The lens molding part 221 of the second insert 220 of the movable core 200, the body part 220c of the second insert 220, the spacer The diameter of the annular spacer 152 as a member and the through hole 212 provided in the recess 211 of the first insert 210 is wider than that of the fixed core 100, and the lens molding surface 221a of the movable core 200 is curved. It is only made into the recessed part.

  The lens molding die 910 of the present embodiment is provided with the above-described nesting fixing structure, so that the positioning accuracy of the nesting can be improved while suppressing an increase in the size of the die and the number of parts. In addition, since the lens thickness adjusting structure is provided, the lens thickness can be easily and finely adjusted.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

100 Fixed side core 110 First insert 111 Recess 111a Opening 111b Inner peripheral surface 111c Bottom surface 112 Through hole 113 Air hole 120 Second insert 120a Front end surface 121 Lens molding portion 121a Lens molding surface 122 Planar portion 120b Rear end surface 120c Body portion 123 Groove portion 123a Opening edge 124 Screw hole 130 O-ring (first elastic member)
130a Notch 140 O-ring (second elastic member)
151,152 Ring spacer (spacer member)
200 movable core 210 first insert 220 second insert 900 injection molding machine 910 lens mold 913 fixed mold plate 915 movable mold plate 916 lens molding chamber PL parting line

Claims (7)

A first nesting having a recess provided with a through-hole on the bottom surface;
A second insert fitted into the recess of the first insert,
When the end surface on the bottom surface side of the second nesting is the front end surface and the end surface on the opposite side is the rear end surface,
The front end surface of the second nest has a lens molding portion that is a protruding portion fitted in the through hole of the concave portion, and a flat portion that is a flat surface facing the bottom surface of the concave portion,
A lens molding mold insert, wherein a first elastic member is disposed between the bottom surface of the recess and the flat portion of the second insert.   2. The lens molding according to claim 1, wherein a spacer member that is in contact with the rear end surface of the second nest is fitted to the recess in an opening side of the recess from the second nest. Nest for molds.   The lens molding die according to claim 1 or 2, wherein the first elastic member is an O-ring. The second nest has a cylindrical body,
Grooves are formed along the circumferential direction on the outer surface of the main body,
The nest for a lens mold according to any one of claims 1 to 3, wherein an O-ring that is a second elastic member is attached to the groove portion.   5. The lens mold nesting according to claim 4, wherein the opening edge of the groove is provided with a radius. An air hole penetrating from the inner peripheral surface to the outside of the first nesting is provided on the inner peripheral surface in the vicinity of the bottom surface of the recess,
The first elastic member has a notch in a part of its circumferential direction,
6. The lens molding insert according to claim 1, wherein the first elastic member is disposed in a direction in which the cutout portion communicates with the air hole.   A lens molding die provided with a movable side mold plate and a fixed side mold plate having a nesting for the lens molding die according to any one of claims 1 to 6.

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