JP6823248B2 - Undercut processing mechanism and molding mold - Google Patents

Description

The present invention relates to an undercut processing mechanism capable of molding an undercut portion and a molding die which are incorporated and used in a molding die for molding a molded product with a fixed mold and a movable mold.

In molding dies for molding a molded product with an undercut between a fixed mold and a movable mold, many undercut processing mechanisms have been developed in a form corresponding to the form of the undercut portion. For example, Patent Document 1 describes an undercut processing apparatus capable of molding a molded product having an undercut portion on the outer periphery of the protruding portion.

In the undercut processing apparatus described in Patent Document 1, a cylindrical inner mold is provided at the tip of the holder, an opening / closing fixing pin is arranged at the center of the holder, and an undercut portion is formed on the outside of the cylindrical inner mold. An outer shape split mold provided with a cavity to be formed is arranged, and a tapered portion is provided on the opening / closing fixing pin and the holder accommodating portion. This undercut processing device uses the tapered portion to radially expand the outer shape split mold as the mold opens, and pulls out the undercut portion.

According to Patent Document 2, if the undercut portion is die-cut while the entire molded product is not supported, not only the die-cutting efficiency of the molded product is not good, but also the molded product may be damaged by forcible drawing. If there is, it is equipped with an undercut molding core, a holder assembled in a fixed mold or a movable mold, and a slider that moves in the die cutting direction of the undercut portion in the holder, and the slider is punched in the die cutting direction before opening the mold. Described is an undercut processing mechanism that can remove only the undercut portion without removing the mold by moving it to.

Japanese Unexamined Patent Publication No. 7-47575 Japanese Unexamined Patent Publication No. 2014-226806

The undercut processing apparatus described in Patent Document 1 can mold a molded product having an undercut portion on the outer periphery of the protruding portion, but the number of parts is large and the structure is complicated. Further, since the undercut portion is die-cut while the entire molded product is not supported, the molded product may be damaged by forcible pulling as pointed out in Patent Document 2.

The undercut processing mechanism described in Patent Document 2 has a small number of parts and can remove only the undercut portion in a state where the mold is not released, so that damage to the molded product can be reliably prevented. Patent Document 2 describes an undercut processing mechanism for forming an undercut portion of a tubular boss and a lateral hole. However, in the undercut processing mechanism described here, structurally, the outer periphery of the protruding portion is formed. It is not possible to mold a molded product with an undercut portion.

An object of the present invention is to provide an undercut processing mechanism and a molding die that have a small number of parts, are easy to incorporate into a mold, and can surely prevent damage to a molded product.

The present invention is an undercut processing mechanism capable of molding an undercut portion, which is attached to and used in a molding die provided with a fixed mold and a movable mold for molding a molded product having an undercut portion. A forming piece composed of two or more dividing pieces for forming the outer peripheral surface of the above, a holding piece that slidably engages with the forming piece to open and close the forming piece, and an inclined surface slidable on the holding piece. It has a slider for advancing and retreating the holding piece so as to open and close the molding piece, and a holder fixed to either the fixed type or the movable type for accommodating the holding piece so as to be able to advance and retreat. The slider and the holding piece are configured to be able to move forward and backward with the fixed mold and the movable mold closed, the holding piece moves along the inclined surface of the slider , and the holder is formed. It is an undercut processing mechanism characterized by having a forming piece guide that guides the piece in the die cutting direction of the undercut portion.

Since this undercut processing mechanism can perform die cutting of the undercut portion with the fixed die and the movable die closed, it is possible to reliably prevent damage to the molded product during die cutting of the undercut portion. it can. Further, in this undercut processing mechanism, the slider advances and retreats the holding piece so as to open and close the molded piece, so that the undercut portion is complicated like a protrusion formed on the outer peripheral surface of the protrusion protruding from the main body of the molded product. Can also be handled. In particular, since the holding piece can move in a direction different from the moving direction of the slider, molding and die cutting can be performed even if the protruding portion protruding from the main body of the molded product is inclined. Further, since the undercut processing mechanism of the present invention is basically composed of a molding piece, a holding piece, a slider, and a holder, the number of parts is small, the structure is easy to incorporate into the mold, and the manufacturing is inexpensive. can do.

Further, in the undercut processing mechanism of the present invention, the dividing piece and the holding piece both have an inclined surface, and are slidably engaged with each other via an engaging means provided on the inclined surface, and two or more pieces are slidably engaged with each other. Each of the divided pieces has a cavity for forming the outer peripheral surface of the undercut portion on the inner surface and the inclined surface on the outer surface, and the forming piece has the holding piece completely housed in the holder. When the dividing pieces come into contact with each other to form the outer peripheral surface of the undercut portion and retract the holding piece, the dividing pieces move along the forming piece guide so as to separate from each other, and the undercut portion is formed. The feature is that die cutting is possible .

According to the present invention, since the inclined directions of the inclined surface of the holding piece and the inclined surface of the sliding split piece are the same, the holding piece and the split piece can be slid smoothly.

In undercut processing mechanism of the present invention, the undercut portion is provided in a projection projecting from the molding body, the central axis of the front Symbol protrusion, has inclined obliquely with respect to the molded article body, before Symbol holder have a holding frame guide for guiding the holding piece in a central axis direction of the projecting portion, the slider is characterized in that to guide the holding piece in a central axis direction of the protrusion.

Further, in the undercut processing mechanism of the present invention, the molded product having the undercut portion is a molded product having a tubular protruding portion protruding from the main body of the molded product, and the undercut portion is formed on the outer peripheral surface of the protruding portion. It is a formed protrusion, and is characterized in that a core pin for forming an inner peripheral surface of the protrusion is attached to the holding piece.

According to the present invention, the undercut portion is a protrusion formed on the outer peripheral surface of the protrusion protruding from the main body of the molded product, and the protruding portion is inclined with respect to the main body of the molded product. It is very useful because it is possible to mold and die-cut a complicated undercut portion that is annular.

In undercut processing mechanism of the present invention, the end face of the fixed or the movable mold the holder is incorporated, has a movable movable mounting member to the mold Opening direction of the mold, said movable mounting The slider is attached to the member, and the holding piece is slidably connected to the slider via an engaging means .

Further, the undercut processing mechanism of the present invention is characterized in that the holder itself is configured as a part of the fixed type or the movable type to which the holder is attached.

According to the present invention, since the fixed type or the movable type can be processed and the holder can be directly provided, the number of parts can be reduced and the cost can be reduced.

Further, the present invention is a molding die including a fixed die, a movable die, and the undercut processing mechanism.

In the present molding die, the undercut portion can be die-cut with the fixed die and the movable die closed, so that damage to the molded product can be reliably prevented. Further, since the undercut processing mechanism is composed of a small number of parts, the molding die can be made compact and can be manufactured at low cost.

According to the present invention, it is possible to provide an undercut processing mechanism and a molding die that have a small number of parts, are easily incorporated into a mold, and can surely prevent damage to a molded product.

It is a perspective view which shows the structure of the molding die apparatus 1 of 1st Embodiment of this invention. It is a perspective view of the holder member 31 of the molding die apparatus 1 of FIG. It is a perspective view of the holding piece 40 and the molding piece 50 of the molding die apparatus 1 of FIG. It is a perspective view of the molding piece 50 of the molding die apparatus 1 of FIG. It is a vertical cross-sectional view explaining the operation at the time of molding of the molding die apparatus 1 of FIG. It is a vertical cross-sectional view explaining the operation at the time of molding of the molding die apparatus 1 of FIG. It is a vertical cross-sectional view explaining operation at the time of mold release of the molding die apparatus 1 of FIG. It is a vertical cross-sectional view explaining operation at the time of mold release of the molding die apparatus 1 of FIG. It is a vertical sectional view explaining the operation at the time of molding of the molding die apparatus 2 of the 2nd Embodiment of this invention. It is a vertical sectional view explaining the operation at the time of molding of the molding die apparatus 2 of the 2nd Embodiment of this invention. It is a vertical cross-sectional view explaining the operation at the time of mold release of the molding die apparatus 2 of the 2nd Embodiment of this invention. It is a vertical cross-sectional view explaining the operation at the time of mold release of the molding die apparatus 2 of the 2nd Embodiment of this invention. It is a figure which shows an example of the molded article which can be molded by the undercut processing mechanism of this invention and a molding die.

FIG. 1 is a perspective view showing a configuration of a molding die device 1 according to a first embodiment of the present invention. FIG. 2 is a perspective view of the holder member 31 of the molding die device 1 of FIG. FIG. 3 is a perspective view of the holding piece 40 and the molding piece 50 of the molding die device 1 of FIG. FIG. 4 is a perspective view of the molding piece 50 of the molding die device 1 of FIG. 5 and 6 are vertical cross-sectional views illustrating the operation of the molding die apparatus 1 of FIG. 1 during molding. 7 and 8 are vertical cross-sectional views illustrating the operation of the molding die apparatus 1 of FIG. 1 at the time of mold release. In FIGS. 5 to 8, some reference numerals are omitted.

The molding die device 1 of the first embodiment of the present invention is a device for molding a molded product P having an undercut portion P1 by a molding die 10. The molded product P has a cross-sectional shape shown in FIGS. 6 to 8, and the undercut portion P1 is formed on the outer peripheral surface of the tubular protruding portion P2 projecting so as to be orthogonal to the molded product main body P3. It is a protruding part. The undercut portion P1 projects perpendicular to the die-cutting direction of the molded product P (vertical direction in the drawing), and is orthogonal to the die-cutting direction of the molded product P (horizontal direction in the drawing). Is the die cutting direction of the undercut portion P1. The material of the molded product P is not limited to a synthetic resin such as plastic, and may be, for example, a metal such as iron or copper.

In the drawing, the molding die 10 includes a fixed die 11 located on the upper side of the molded product P, a movable die 12 located on the lower side of the molded product P and movable in the die cutting direction of the molded product P, and an undercut. It comprises an undercut processing mechanism for forming the portion P1 (protruding portion P2).

The undercut processing mechanism is fixed to the fixed mold 11 and a movable mounting member 20 which is arranged above the fixed mold 11 and can move in a direction parallel to the mold opening direction (vertical direction in the drawing) of the molding die 10. The holder 30, the holding piece 40 which is fixed to the movable mounting member 20 and slides in the holder 30 to advance and retreat, and the holding piece 40 are slidably engaged with each other, and the inside of the holder 30 is interlocked with the advance and retreat of the holding piece 40. Is composed of a molding piece 50 that slides in the die-cutting direction of the undercut portion P1 to open and close.

As the movable mounting member 20, the existing member included in the molding die device can be diverted. In this case, the movable mounting member 20 may not be included in the undercut processing mechanism.

The movable mounting member 20 is made of a flat plate material and moves up and down in a state of being parallel to the upper end surface of the fixed mold 11. A holding piece 40 is fixed to the lower surface side of the movable mounting member 20 via a bolt, a knock pin, or the like. A drive mechanism (not shown) for moving the movable mounting member 20 up and down is connected to the movable mounting member 20.

The holder 30 accommodates the holding piece 40 so as to be able to advance and retreat, guides the holding piece 40 at the same angle as the protruding portion P2 of the molded product P, and guides the molding piece 50 in the die cutting direction of the undercut portion P1. The holder 30 is formed by combining a pair of symmetrical holder members 31 having a U-shaped cross section, and is formed in a fixed mold 11 so as to be formed in a box shape having an internal space in which the upper end surface and the lower end surface are open. It is fixed to the mounting hole 15 via a mounting member 16.

On the inner wall at the center of the holder member 31, a concave groove cross-sectional molding piece guide 32 that guides the molding piece 50 in the die cutting direction of the undercut portion P1 is formed in the horizontal direction. Further, the inner walls on both outer sides of the holder member 31 function as a holding piece guide 33 for guiding the holding piece 40.

The molding piece guide 32 is formed over the entire width of the inner wall of the holder member 31, but is not limited to this, and the molding piece 50 is moved from the molding position shown in FIG. 6 to the mold release position shown in FIG. It suffices if it can be guided in the die-cutting direction of the undercut portion P1.

Further, the molding piece guide 32 is not limited to the one having a concave groove cross-sectional shape, and may be, for example, a convex portion, a dovetail groove, a ridge, or the like, or a linear guide or the like provided on the inner wall of the holder member 31. .. In short, the structure may be such that the forming piece 50 can be guided in the die cutting direction of the undercut portion P1. The molding piece 50 guided by the molding piece guide 32 may also have an optimum configuration as appropriate according to the configuration of the molding piece guide 32.

The holding piece guide 33 guides the holding piece 40 at the same angle as the protruding portion P2 of the molded product P (in the direction of the central axis of the protruding portion P2). In the present embodiment, the inner walls on both outer sides of the holder member 31 formed in a vertical plane function as the holding piece guide 33, and guide the holding piece 40 up and down.

Like the molding piece guide 32, the holding piece guide 33 is not limited to this, and may be, for example, a dovetail groove or a ridge formed on the inner wall of the holder member 31, and a linear guide on the inner wall of the holder member 31. Etc. may be provided. In short, the holding piece 40 may be configured so as to be able to be guided in the direction of the central axis of the protruding portion P2 of the molded product P from the molding position shown in FIG. 6 to the mold release position shown in FIG. The holding piece 40 guided by the holding piece guide 33 may also have an optimum configuration as appropriate according to the configuration of the holding piece guide 33.

On both outer outer walls of the holder member 31, a concave groove cross-sectional type locking groove 34 that locks to the convex portion 17 of the mounting member 16 is formed, and the convex portion 17 of the mounting member 16 is formed into the locking groove 34. It is fitted and locked, the mounting member 16 is fixed to the fixed mold 11 via bolts, knock pins, etc., and the holder 30 is fixed to the mounting hole 15 of the fixed mold 11.

The configuration of the holder 30 is not limited to a specific configuration, and may be configured by one square tube member or may be composed of three or more holder members (not shown). The holder 30 can also be configured as a part of the fixed mold 11.

The holding piece 40 slidably engages with the molding piece 50 and moves back and forth to open and close the molding piece 50. The base end portion (upper side in the drawing) of the holding piece 40 is fixed to the movable mounting member 20, and the holder is interlocked with the vertical movement of the movable mounting member 20 in a state where the fixed mold 11 and the movable mold 12 are closed. The inside of 30 is advanced and retreated along the holding piece guide 33.

The holding piece 40 is a member having a notch 41 cut out in an isosceles trapezoidal shape at the lower center of a rectangular block member having a size that can be accommodated in the holder 30 without a gap, and is arranged in an inverted V shape. The notch 41 has two inclined surfaces 42, and a core pin 44 for forming the inner peripheral surface of the protruding portion P2 of the molded product P is attached so as to penetrate the ceiling surface 43 of the notch 41 from the upper surface. Further, on the upper surface of the holding piece 40, two mounting holes 46 for fixing to the movable mounting member 20 are formed via bolts, knock pins, or the like.

A ridge 45, which is an engaging means with the forming piece 50, is formed on the inclined surface 42 of the holding piece 40, and the ridge 45 and the dovetail groove 53 formed on the inclined surface 52 of the forming piece 50 described later are formed. The holding piece 40 and the forming piece 50 are slidably engaged with each other along the inclined surfaces 42 and 52. The engaging means of the holding piece 40 and the forming piece 50 is not limited to the one using the ridge 45 and the dovetail groove 53, and for example, a linear guide or the like can be used.

The inclination angle of the inclined surface 42 of the holding piece 40 can be appropriately set to an optimum angle in consideration of the space for arranging the undercut processing mechanism, the stroke of the movable mounting member 20, and the like. By increasing the inclination angle of the inclined surface 42 of the holding piece 40 with respect to the vertical plane, the vertical movement stroke of the movable mounting member 20 required to move the forming piece 50 can be reduced, but the holding piece 40 (holder 30) The width of is relatively large.

The core pin 44 is a member of an elongated cylindrical body having an enlarged base end portion, and the enlarged base end portion is used as a retainer so that the central axis line coincides with the central axis line of the protruding portion P2 of the molded product P. , It is attached so as to penetrate the ceiling surface 43 of the notch 41 from the upper surface of the holding piece 40. The cross-sectional shape of the core pin 44 is not limited to a specific shape, and can be appropriately changed according to the cross-sectional shape of the inner peripheral surface of the protruding portion P2 of the molded product P.

The molding piece 50 is composed of a pair of symmetrical dividing pieces 51 that can be divided with the central axis of the protruding portion P2 of the molded product P as a boundary, and the outer peripheral surface of the undercut portion P1 (protruding portion P2) of the molded product P is formed. Mold. The forming piece 50 (a pair of split pieces 51) has no gap in the notch 41 of the holding piece 40 so that the split pieces 51 abut against each other in a closed state in which the holding piece 40 is completely housed in the holder 30. It is formed in a shape that can be accommodated.

The split piece 51 is a member in which one end surface of the rectangular block member is cut off to form an inclined surface 52 inclined at the same angle as the inclined surface 42 of the holding piece 40, and is slidably fitted to the forming piece guide 32 of the holder 30. A convex portion 54 is formed, a cavity 55 for forming the outer peripheral surface of the undercut portion P1 (protruding portion P2), and a guide groove 56 serving as a passage path for the core pin 44 are formed.

The inclined surfaces 52 of the two dividing pieces 51 are formed in opposite directions so that they can slide along one of the inclined surfaces 42 of the holding pieces 40 arranged in a V shape. Further, the inclined surface 52 of the dividing piece 51 is formed with a dovetail groove 53 slidably engaged with the ridge 45 of the holding piece 40.

The convex portion 54 of the dividing piece 51 is horizontally formed over the entire width on both side surfaces of the inclined surface 52 so as to be slidable by being fitted to the forming piece guide 32 of the holder 30.

The cavities 55 of the two dividing pieces 51 are formed at the lower part of the side surface opposite to the inclined surface 52 so that the protruding portion P2 of the molded product P can be formed when the two dividing pieces 51 come into contact with each other. There is.

The guide grooves 56 of the two dividing pieces 51 allow the core pin 44 to pass through when the two dividing pieces 51 come into contact with each other, respectively, on the side surface where the cavity 55 is formed, from the center of the upper end to the cavity 55 in the vertical direction. It is formed in a semicircular groove cross-sectional shape so as to communicate with each other.

The two split pieces 51 engage the dovetail groove 53 with the ridge 45 of the holding piece 40 so that the side surfaces on which the cavity 55 is formed face each other, and hold the split pieces 51 so as to be slidable along the inclined surfaces 42 and 52. It is attached to the piece 40. Further, the split piece 51 has a convex portion 54 fitted in the molding piece guide 32 of the holder 30 and is slidably housed in the holder 30 along the molding piece guide 32.

Next, the operation of the molding die device 1 of the present embodiment will be described with reference to FIGS. 5 to 8. In the description, the molding die 10 is used as the injection molding die. At the time of molding, the movable mold 12 is raised and the movable mounting member 20 is lowered until it comes into contact with the fixed mold 11. The holding piece 40 is completely housed in the holder 30, and the split pieces 51 are in contact with each other to form the molding piece. 50 is completely housed in the holding piece 40 and is in a molded closed state (see FIG. 5). The molding material is injected into the cavity 13 for molding the molded product main body P3 and the cavity 55 for molding the protruding portion P2, which is the gap between the fixed mold 11 and the movable mold 12 in the mold closed state, and the molded product P is molded. (See FIG. 6).

When the molded product P is cured, mold release is started. First, the movable mounting member 20 is raised and the undercut portion P1 is die-cut (see FIG. 7). When the movable mounting member 20 rises, the holding piece 40 moves backward (up) while being guided by the holding piece guide 33 of the holder 30. When the holding piece 40 retracts, the molding piece 50 engaged with the holding piece 40 slides along the inclined surfaces 42 and 52. At this time, since the sliding direction of the forming piece 50 is restricted in the horizontal direction by the forming piece guide 32 of the holder 30, the die-cutting direction of the undercut portion P1 is set so that the pair of dividing pieces 51 are separated from each other. Left and right). As a result, the undercut portion P1 is removed from the cavity 55 of the molding piece 50, and the molded product P can be die-cut.

When the undercut portion P1 is removed from the cavity 55, the movable mold 12 is lowered with the molded product P placed in the cavity 55 to open the mold, and the mold release is completed (see FIG. 8). After the mold release is completed and the molded product P is taken out, the mold is closed again to mold the next molded product P (return to FIG. 5).

As described above, according to the molding die device 1 of the present embodiment, the undercut portion P1 can be die-cut with the fixed die 11 and the movable die 12 closed, so that the molded product P is damaged. Can be reliably prevented.

Further, according to the molding die device 1 of the present embodiment, the undercut processing mechanism is a mold of the undercut portion P1 so that the dividing pieces 51 constituting the molding piece 50 are separated from each other when the undercut portion P1 is die-cut. Since it moves in the pulling direction, it can correspond to a complicated undercut portion P1 such as a protrusion formed on the outer peripheral surface of the protrusion P2. Further, since the undercut processing mechanism is basically composed of the molding piece 50, the holding piece 40, and the holder 30, the number of parts is small, the structure is easy to incorporate into the mold, and the manufacturing is inexpensive. Can be done.

Further, according to the molding die device 1 of the present embodiment, in the undercut processing mechanism, the molding piece 50 is composed of two dividing pieces 51, and the molding piece 50 and the holding piece 40 are simple in shape, so that processing is easy. It can be manufactured at low cost.

Further, according to the molding die device 1 of the present embodiment, the undercut processing mechanism has a cavity 55 and a core pin 44, and also functions as a molding core. Therefore, the undercut processing mechanism can be rephrased as a molding core having an undercut processing function. Such a molded core is very useful because it is possible to perform die cutting of the undercut portion P1 without separately providing an undercut processing mechanism.

9 and 10 are vertical cross-sectional views illustrating the operation of the molding die device 2 of the second embodiment of the present invention at the time of molding. 11 and 12 are vertical cross-sectional views illustrating the operation of the molding die device 2 of the second embodiment of the present invention at the time of mold release. In FIGS. 9 to 12, some reference numerals are omitted. The same components as those of the molding die apparatus 1 of the first embodiment shown in FIGS. 1 to 8 are designated by the same reference numerals, and the description thereof will be omitted.

The molding die device 2 of the second embodiment has the same basic configuration as the molding die device 1 of the first embodiment, but the protruding portion P'2 of the molded product P'to be molded is the molded product main body. It is inclined with respect to P'3, and the undercut processing mechanism incorporated in the molding die 110 has a configuration corresponding to this.

The undercut processing mechanism of the molding die device 2 of the present embodiment includes a movable mounting member 20, a holder 130 fixed to the fixed mold 11, a slider 160 fixed to the movable mounting member 20, and a slider 160. A holding piece 140 that movably engages and slides in and out of the holder 130, and an undercut portion that slidably engages with the holding piece 140 and interlocks with the advancement and retreat of the holding piece 140 in the holder 130. It is composed of a molding piece 150 that slides in the die cutting direction (left and right) of P'1 to open and close.

The holder 130 guides the holding piece 140 at the same angle as the protruding portion P'2 of the molded product P'(in the direction of the central axis of the protruding portion P'2) on both outer sides of the holder member 131 serving as the holding piece guide 33. The inner wall is inclined at the same angle as the protrusion P'2.

The slider 160 is a member that slidably engages with the holding piece 140 and moves the holding piece 140 forward and backward at the same angle as the protruding portion P'2 of the molded product P'in conjunction with the vertical movement of the movable mounting member 20. This is a member in which an inclined surface 161 is formed at the lower end of the rectangular block member.

The inclined surface 161 of the slider 160 is inclined at an angle orthogonal to the central axis of the protruding portion P'2 of the molded product P', and is slidably engaged with the dovetail groove 141 of the holding piece 140 described later. It has a ridge 162.

The holding piece 140 is formed in a shape in which the lower surface of the holding piece 40 of the molding die device 1 of the first embodiment is inclined, and the ant slidably engages with the protrusion 162 of the slider 160 on the upper surface. It has a groove 141. The upper surface of the holding piece 140 faces parallel to the inclined surface 161 of the slider 160, the central axis of the core pin 44 is arranged so as to coincide with the central axis of the protruding portion P'2 of the molded product P', and the lower surface is closed. It is formed so as to match the height of the lower surface of the fixed mold 11 in the state of.

The molding piece 150 is composed of a pair of dividing pieces 151 that can be divided with the central axis of the protruding portion P'2 of the molded product P'as a boundary, and the undercut portion P'1 (protruding portion P'2) of the molded product P'. Mold the outer peripheral surface of. The forming piece 150 (a pair of dividing pieces 151) is formed in a shape that can be accommodated in the notch 41 of the holding piece 140 without a gap so that the dividing pieces 151 come into contact with each other in the closed state.

The cavities 155 of the two dividing pieces 151 can form the protruding portion P'2 of the molded product P'when the two dividing pieces 151 come into contact with each other, respectively, at the lower part of the side surface opposite to the inclined surface 52. It is formed.

Next, the operation of the molding die device 2 of the present embodiment will be described with reference to FIGS. 9 to 12. In the description, the molding die 110 is used as the injection molding die. At the time of molding, the movable mold 12 is raised and the movable mounting member 20 is lowered until it comes into contact with the fixed mold 11. The holding piece 140 is completely housed in the holder 130, and the split pieces 151 are in contact with each other to form the molding piece. The 150 is completely housed in the holding piece 140 and is in a closed mold state (see FIG. 9). The molding material is injected into the cavities 13 and 155 with the mold closed, and the molded product P'is molded (see FIG. 10).

When the molded product P'is cured, mold release is started. First, the movable mounting member 20 is raised and the undercut portion P'1 is die-cut (see FIG. 11). When the movable mounting member 20 rises, the holding piece 140 is guided by the holding piece guide 33 of the holder 130 while sliding along the inclined surface 161 of the slider 160, and is directed toward the central axis of the protruding portion P'2 of the molded product P'. Retreat to. When the holding piece 140 retracts, the molding piece 150 engaged with the holding piece 140 slides along the inclined surfaces 42 and 52. At this time, since the sliding direction of the forming piece 150 is restricted in the horizontal direction by the forming piece guide 32 of the holder 130, the undercut portion P'1 is die-cut so that the pair of dividing pieces 151 are separated from each other. Move in the direction (left and right). As a result, the undercut portion P'1 is disengaged from the cavity 155 of the molding piece 150, and the molded product P'can be die-cut.

When the undercut portion P'1 is disengaged from the cavity 155, the movable mold 12 is lowered with the molded product P'placed to open the mold, and the mold release is completed (see FIG. 12). After the mold release is completed and the molded product P'is taken out, the mold is closed again to mold the next molded product P'(return to FIG. 9).

According to the molding die device 2 of the present embodiment, the undercut portion P'1 is a protruding portion formed on the outer peripheral surface of the protruding portion P'2 protruding from the molded product main body P'3, and further protrudes. A complicated undercut portion P'1 in which the portion P'2 is inclined with respect to the molded product main body P'3 and the protruding portion P'2 is annular can also be molded and die-cut. It is useful.

The undercut processing mechanism and the molding die of the present invention have been described above using the molding die devices 1 and 2 of the first and second embodiments, but the undercut processing mechanism and the molding die of the present invention have been described above. The mold is not limited to the above embodiment, and can be modified and used without changing the gist. For example, it is possible to form a protrusion without a hollow portion in the molded product without using a core pin.

Further, in the molding mold devices 1 and 2 of the first and second embodiments, the fixed mold 11 and the movable mold 12 may be reversed. That is, in the molding mold devices 1 and 2 of the first and second embodiments, the fixed mold 11 does not have to move up and down, and the movable mold 12 does not have to move.

Further, the holder of the undercut processing mechanism of the present invention is not limited to a square cylinder shape, and may be, for example, a cylindrical shape. At this time, the shape of the holding piece and the slider may be appropriately determined according to the shape of the holder.

Further, in the undercut processing mechanism of the present invention, the forming piece may be composed of three or more divided pieces. At this time, the shape of the holder and the holding piece may be changed according to the number, shape, and arrangement of the divided pieces. For example, the forming piece guide of the holder is formed so that each divided piece can be guided in the die cutting direction of the undercut portion. Further, the holding piece is formed with a notch portion capable of accommodating all the divided pieces without a gap, and the notch portion is formed with one or more inclined surfaces and engaging means, and the inclined surfaces are engaged with each other. It is formed so that the inclined surface and the inclined direction of the sliding split piece coincide with each other.

Further, the molded product (undercut portion) that can be molded by the undercut processing mechanism and the molding die of the present invention is not limited to those exemplified in the first and second embodiments, and is not limited to those exemplified in FIG. A so-called bamboo nipple having two or more projecting portions P2 arranged in a row as shown in (a), or an undercut portion P15 having a plurality of tapered portions as shown in FIG. 13 (b). , A nipple having a plurality of arc-shaped undercut portions P16 as shown in FIG. 13 (c), and an injection port having an undercut portion P17 as shown in FIG. 13 (d) to supply grease. , So-called grease nipples and the like can also be included.

Further, the undercut portion that can be processed by the undercut processing mechanism of the present invention is not limited to the one that protrudes in the direction orthogonal to the die cutting direction of the molded product, and is not limited to the one that protrudes in the direction orthogonal to the die cutting direction of the molded product. It is also possible to include those that intersect diagonally and protrude. At this time, the die-cutting direction of the undercut portion is the same as the protruding direction of the undercut portion so that the molded product (undercut portion) is not damaged during die cutting. The undercut processing mechanism is provided with a forming piece guide so that the moving direction of the forming piece coincides with the die cutting direction of the undercut portion.

As described above, a preferred embodiment has been described with reference to the drawings, but those skilled in the art will easily assume various changes and modifications within a self-evident range by looking at the present specification. Therefore, such changes and amendments are construed as being within the scope of the invention as defined by the claims.

10 Molding mold 11 Fixed mold 12 Movable mold 20 Movable mounting member 30, 130 Holder 32 Molding piece guide 33 Holding piece guide 40, 140 Holding piece 42, 52 Inclined surface 44 Core pin 45 Protrusion 50, 150 Molding piece 51, 151 Dividing piece 53 Dovetail groove 55, 155 Cavity P, P'Molded product P1, P'1 Undercut part P2, P'2 Protruding part P3, P'3 Molded product body

Claims (7)

An undercut processing mechanism capable of molding an undercut portion, which is used by being attached to a molding die having a fixed mold and a movable mold for molding a molded product having an undercut portion.
A molding piece consisting of two or more dividing pieces for molding the outer peripheral surface of the undercut portion, and
A holding piece that slidably engages with the molding piece to open and close the molding piece,
It has a slidable inclined surface to the holding piece, and a slider for advancing and retracting said holding pieces so as to open and close the mold piece,
A holder fixed to either the fixed type or the movable type that accommodates the holding piece so as to be able to move forward and backward.
Have,
The slider and the holding piece are configured to be able to move forward and backward with the fixed type and the movable type closed.
The holding piece moves along the inclined surface of the slider and moves.
The holder has a molding piece guide that guides the molding piece in the die-cutting direction of the undercut portion. The undercut portion is provided on the protruding portion protruding from the main body of the molded product.
The central axis of the protruding portion is inclined with respect to the main body of the molded product.
The holder has a holding piece guide that guides the holding piece in the direction of the central axis of the protrusion.
The undercut processing mechanism according to claim 1, wherein the slider guides the holding piece in the direction of the central axis of the protruding portion. A movable mounting member that can move in the mold opening direction of the molding die is provided on the end face of the fixed mold or the movable mold in which the holder is incorporated.
The slider is attached to the movable mounting member,
The undercut processing mechanism according to claim 1 or 2, wherein the holding piece is slidably connected to the slider via an engaging means. The dividing piece and the holding piece both have an inclined surface, and are slidably engaged with each other via an engaging means provided on the inclined surface.
Each of the two or more divided pieces has a cavity on the inner surface for forming the outer peripheral surface of the undercut portion, and has the inclined surface on the outer surface.
When the holding piece is completely housed in the holder, the divided pieces come into contact with each other to form the outer peripheral surface of the undercut portion, and when the holding piece is retracted, the divided pieces come into contact with each other. The undercut processing mechanism according to any one of claims 1 to 3, wherein the undercut portion moves along the molding piece guide so as to be separated from each other, and the undercut portion can be die-cut. The molded product having the undercut portion is a molded product having a tubular protruding portion protruding from the molded product main body.
The undercut portion is a protrusion formed on the outer peripheral surface of the protrusion.
The undercut processing mechanism according to any one of claims 1 to 4, wherein a core pin for forming an inner peripheral surface of the protruding portion is attached to the holding piece. The undercut processing mechanism according to any one of claims 1 to 5, wherein the holder itself is configured as a part of the fixed type or the movable type to which the holder is attached. Fixed type and
Movable and
The undercut processing mechanism according to any one of claims 1 to 5 .
A molding die characterized by being provided with.

Images