JP4990922B2 - Injection mold - Google Patents

Description

  The present invention relates to an injection mold for a resin molded product having an undercut portion on the inner surface of a hollow portion.

  As shown in FIG. 7 ((a) is a perspective view and (b) is a sectional view of the central axis), a resin molded product P having an undercut portion U protruding from the inner surface of the hollow portion H is injected by a mold. In the case of molding, since the male part of the mold is locked to the undercut part, a method is adopted in which the male part is divided and formed, and the mold is released after being reduced to a smaller diameter than the part to be locked. The inventor of the present application also proposes an injection mold in which the male part is divided into a center core, a main slide core and a sub slide core in Patent Document 1.

JP 2002-46158 A

  However, although the document 1 shows the divided configuration of the male part, the mechanism for operating the divided parts is not described in detail. In this mold, it is necessary to sequentially operate each component, and if the mechanism for this is complicated, the cost becomes very high. It has also been desired to be able to cope with the downsizing and upsizing of the male part and to increase the protrusion length or the depression depth of the undercut part with respect to the inner diameter of the hollow part.

  The present invention has been made in view of the above circumstances, and is a resin-molded injection mold having an undercut portion on the inner surface of a hollow portion, which can be driven by a single piston that reciprocates, It is an object of the present invention to provide an injection mold that can cope with downsizing / upsizing of a mold part and upsizing of an undercut part.

  The invention according to claim 1 of the present invention is an injection mold for a resin molded product having an undercut portion on the inner surface of a hollow portion, the male portion forming the hollow portion, and the drive for moving the male portion And the male part is composed of a center core and a main slide core and a sub slide core alternately positioned on the outer periphery of the center core, and the drive mechanism is a piston that moves forward and backward, and a back plate that is integral with the piston A core plate that is located on the front side of the back plate and on which the main slide core slides in the inner and outer peripheral directions, and a first pin, a second pin, and a third pin that are located on the periphery of the back plate and the core plate A pin, a fourth pin, a fifth pin and a sixth pin, and a cylindrical housing for housing them; the fifth pin, the sixth pin and the center core are integrated with the back plate; and the third pin And the fourth pin are integral with the core plate, and when the piston is retracted, the fifth pin, the sixth pin, the center core and the back plate are retracted together with the piston, and then the second pin is engaged with the back plate. The main slide core is moved to the inner peripheral side by the sliding means, and then the third pin is engaged with the back plate and moved backward, and the core plate and the main slide core are moved backward, and then the first pin However, it engages with the core plate and moves backward, and the sliding means moves the sub-slide core to the inner peripheral side to allow the resin molded product to be taken out.When the piston advances, the fifth pin, the sixth pin, The center core and the back plate are moved forward together with the piston, and the sixth pin is moved forward by being connected to the third pin by the connecting means. The core and the fourth pin are advanced, the fifth pin is connected to the second pin by the connecting means to advance, the fourth pin is connected to the first pin by the connecting means, and the first pin is advanced by the sliding means. After moving the slide core to the outer peripheral side, the connection between the fourth pin and the first pin is released by the connecting means, the advancement of the first pin is stopped, and then when the main slide core reaches the front end, the connecting means The connection of the third pin is released, the advancement of the third pin is stopped, and at the same time, the advancement of the core plate and the main slide core is stopped, and then the second pin moves the main slide core to the outer peripheral side by the sliding means. After that, the connection between the fifth pin and the second pin is released by the connecting means, the advancement of the second pin is stopped, and then the center core reaches the front end, and the resin molded product can be molded. To do.

  The invention according to claim 2 of the present invention is characterized in that the sliding means protrudes from the guide groove formed on the first pin and the second pin and inclined to the inner peripheral side toward the front side, and the sub slide core and the main slide core. And a guide protrusion that engages with the guide groove of each of the first pin and the second pin.

  According to the invention of claim 3 of the present invention, the first pin, the second pin and the third pin are in sliding contact with the inner peripheral side surface of the housing, and the inner peripheral side surface of the first pin, the second pin and the third pin are in contact with each other. The fourth pin, the fifth pin and the sixth pin are in sliding contact with each other, and the connecting means is an outer hemispherical hole formed on the inner peripheral side surface of the housing, and the inner and outer peripheral directions of the first pin, the second pin and the third pin. A through hole formed on the outer peripheral side surface of the fourth pin, the fifth pin and the sixth pin, and a sphere rolling inside the outer hemispheric hole, the through hole and the inner hemispheric hole, and the first pin The fourth pin, the second pin and the fifth pin, the third pin and the sixth pin are connected to each other by connecting the through hole and the inner hemispherical hole, the outer hemispherical hole of the housing, the first pin, the second pin, and By connecting the through holes of the third pins, the pins Characterized in that the connection is released.

  According to the invention of claim 1 of the present invention, the first to sixth pins, the back plate and the core plate are interlocked with the center core, the main slide core and the sub slide core constituting the male part, By providing the sliding means and the connecting means, the male part can be divided and connected by only a single piston that moves forward and backward.

  According to the invention of the second aspect of the present invention, the main slide core and the sub slide core can be driven by converting the forward and backward movement of the piston into the movement in the inner and outer peripheral directions with a simple configuration. By changing the length and inclination angle of the guide groove, the amount of movement of the main slide core and sub slide core can be adjusted, and if the amount of movement is increased, the undercut portion can be enlarged accordingly. .

  According to the third aspect of the present invention, each part of the mold can be sequentially advanced by a necessary amount. Since this connecting means has a simple configuration including a sphere, a hemispherical hole into which the sphere is inserted, and a through-hole, it can be easily reduced in size and size.

The longitudinal cross-sectional view of the metal mold | die for injection molding of this invention. The cross-sectional view of the injection mold. Explanatory drawing which shows operation | movement of a male type | mold part. Explanatory drawing of a sliding means. Explanatory drawing of a connection means. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Explanatory drawing which shows operation | movement of a drive mechanism. Schematic of the resin molded product which has an undercut part.

  A specific configuration of the injection mold according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the entire mold, and FIG. 2 is a transverse sectional view. However, FIG. 1 is a schematic diagram different from an actual cross-sectional view, showing the configuration of the main slide core 2 and its connected portion on the right half of the drawing, and the configuration of the auxiliary slide core 3 and its connected portion on the left half. It is a simple figure. FIG. 2 is a top view of the movable mold 200 with the stripper plate 201 and the mounting plate 8a removed. The front-rear direction refers to the up-down direction in FIG. The present mold includes a fixed mold 100 and a movable mold 200 that can be separated and approached to the fixed mold 100. The fixed mold 100 has a cavity plate 101 that forms an outer surface portion of a resin molded product, and a runner 102 and a gate 103 for pouring resin are formed on the cavity plate 101. The movable mold 200 includes a stripper plate 201 that comes into contact with the cavity plate 101, a male mold part 40 that forms a hollow part of a resin molded product, and a drive mechanism 50 that moves the male mold part 40. The stripper plate 201 is positioned at the front end of the movable mold 200, and the male mold portion 40 projects forward from an insertion hole 202 formed at the center thereof. The drive mechanism 50 is located behind the stripper plate 201.

  The male part 40 includes a center core 1, and four main slide cores 2 and four sub slide cores 3 that are alternately positioned on the outer periphery of the center core 1. The center core 1 has a rod shape, and the cross-sectional shape has a triangular protrusion around a square. The main slide core 2 is substantially L-shaped, has a head portion 2a and a leg portion 2b, and is mounted on a core plate 6 described later so as to be slidable in the inner and outer peripheral directions. The head 2a is formed with a recess 2c that forms an undercut portion U of the resin molded product P, and the leg 2b is provided with a guide projection 22 that constitutes a sliding means 20 described later. The auxiliary slide core 3 is substantially L-shaped, has a head portion 3a and a leg portion 3b, and is attached to the rear surface of the stripper plate 201 by an attachment plate 8b so as to be slidable in the inner and outer peripheral directions. The head 3a is formed with a recess 3c that forms an undercut portion U of the resin molded product P, and the leg 3b is provided with a guide protrusion 22 that constitutes sliding means 20 described later. Then, the center core 1, the head 2 a of the main slide core 2, and the head 3 a of the sub slide core 3 are combined to form a solid cylindrical shape and form the inner surface portion of the resin molded product P.

  Next, the operation of the male mold portion 40 configured in this manner will be described with reference to FIG. FIG. 3 is a top view of the state of the center core 1, the head 2a of the main slide core 2, and the head 3a of the sub slide core 3 in each process of operations (a), (b), and (c). , (D), (e), and (f) are longitudinal sectional views corresponding to (a), (b), and (c), respectively. In the initial state, the center core 1, the main slide core 2 and the sub slide core 3 are joined, and the front ends of the core core 1, the main slide core 2 and the sub slide core 3 are flush with each other. (FIGS. 3A and 3D). In this state, the resin melt | dissolved in the cavity C is poured, and the resin molded product P is shape | molded. When the resin is cured, the center core 1 is first retracted, and then the main slide core 2 is slid toward the inner peripheral side (FIGS. 3B and 3E). Thereby, the main slide core 2 can be retracted through the insertion hole 202 of the stripper plate 201 without being caught by the undercut portion U of the resin molded product. If the sub-slide core 3 is further slid to the inner peripheral side (FIGS. 3C and 3F), the portion that engages with the undercut portion U disappears, and the resin molded product P can be removed. Note that the reverse procedure is used when returning to the initial state.

  The drive mechanism 50 moves the center core 1, the main slide core 2 and the sub slide core 3 in this way. The drive mechanism 50 includes a piston 4, a back plate 5, a core plate 6, a first pin 11, a second pin 12, a third pin 13, a fourth pin 14, a fifth pin 15, a sixth pin 16 and a housing 7. . The piston 4 is moved forward and backward by an air cylinder or a hydraulic cylinder. The back plate 5 is substantially square and is integrated with the piston 4. A center core 1 is integrally attached to the center of the back plate 5 and protrudes to the front side. The core plate 6 is substantially square and is located on the front side of the back plate 5. A hole is formed in the center, the center core 1 passes therethrough, and the main slide core 2 is mounted on the front surface of the core plate 6 so as to be slidable in the inner and outer peripheral directions by a mounting plate 8a. It is. The first pin 11, the second pin 12, the third pin 13, the fourth pin 14, the fifth pin 15, and the sixth pin 16 are located at the peripheral portions of the back plate 5 and the core plate 6. . Each pin extends in the front-rear direction, and there is one pin for each of the pair of main slide core 2 and sub slide core 3 (that is, four pins each), and each of the back plate 5 and the core plate 6 One is arranged on the side. More specifically, the first pin 11, the second pin 12 and the third pin 13 are located on the peripheral portions of the back plate 5 and the core plate 6, and the first pin 11, the second pin 12 and the third pin 13 are The fourth pin 14, the fifth pin 15, and the sixth pin 16 are in sliding contact with the inner peripheral side surface, respectively. Among the pins, the fifth pin 15 and the sixth pin 16 are integral with the back plate 5, and the third pin 13 and the fourth pin 14 are integral with the core plate 6. The first pin 11 and the second pin 12 are connected to the sub slide core 3 and the main slide core 2 via the sliding means 20, respectively. Further, the first pin 11, the second pin 12 and the second pin 12 are connected to each other. The three pins 13 are connected to the fourth pin 14, the fifth pin 15, and the sixth pin 16 via the connecting means 30, respectively. All these elements are accommodated in a housing 7 having a substantially rectangular tube shape. The cross-sectional shape of the inner peripheral side surface of the housing 7 is substantially the same as the shape of the back plate 5 and the core plate 6, and the first pin 11 and the second pin provided on the back plate 5 and the core plate 6 and their peripheral portions. The 12 and the third pin 13 are in sliding contact with the inner peripheral side surface of the housing 7.

  Next, the configuration of the sliding means 20 will be described. FIG. 4 shows the sliding means 20 that connects the second pin 12 and the main slide core 2. The sliding means 20 includes a guide groove 21 formed on the second pin 12 and a guide protrusion 22 provided on the leg 2 b of the main slide core 2. The guide groove 21 is inclined toward the inner peripheral side toward the front side, and the guide protrusion 22 is substantially cylindrical and engages with the guide groove 21. With this configuration, when the second pin 12 moves forward, the guide protrusion 22 slides in the guide groove 21 and the main slide core 2 moves to the outer peripheral side. Conversely, if the second pin 12 moves backward, the main slide core 2 moves to the inner peripheral side. The sliding means for connecting the first pin 11 and the auxiliary slide core 3 also includes a guide groove formed on the first pin and a guide protrusion provided on the leg of the auxiliary slide core, and has the same configuration as described above. It is.

  Next, the configuration of the connecting means 30 will be described. FIG. 5 shows connecting means 30 for connecting the first pin 11 and the fourth pin 14. The connecting means 30 includes an outer hemispheric hole 31 provided on the inner peripheral side surface of the housing 7, a through hole 32 provided on the first pin 11, an inner hemispheric hole 33 provided on the outer peripheral side surface of the fourth pin 14, and an outer hemisphere. It consists of a sphere 34 that rolls inside the hole 31, the through-hole 32 and the inner hemispherical hole 33. The outer hemispherical hole 31, the through hole 32, and the inner hemispherical hole 33 have the same diameter, and the sphere 34 has substantially the same diameter. Here, considering the case where the fourth pin 14 moves forward, the through-hole 32 and the inner hemispherical hole 33 communicate with each other, and in the state where the sphere 34 exists therein (FIG. 5A), the first pin 11 and the 4th pin 14 are connected, and the 4th pin 14 and the 1st pin 11 move forward integrally. Then, when the first pin 11 moves forward and reaches the position where the through hole 32 communicates with the outer hemispherical hole 31, the sphere 34 rolls to the outer peripheral side (FIG. 5B), and the first pin 11 and the fourth pin 14. The first pin 11 stops, and only the fourth pin 14 moves forward (FIG. 5C). As for the connecting means for connecting the second pin and the fifth pin and the third pin and the sixth pin, the outer hemispherical hole provided in the housing, the through hole provided in the second pin or the third pin, the fifth pin or It consists of an inner hemispherical hole provided on the sixth pin and a sphere, and has the same configuration as described above.

  Next, the operation of the mold configured as described above will be described with reference to FIGS. However, FIGS. 6A to 6H show the configuration of the main slide core 2 and the second pin 12 and the fifth pin 15 connected to the right half in the overall view, and the sub slide core 3 and the link to the left half. The configuration of the first pin 11 and the fourth pin 14 is shown, and the configuration of the third pin 13 and the sixth pin 16 that are originally located on the back side of the first pin 11 and the fourth pin 14 is shown on the left side of the overall view. It is the schematic diagram shown. In addition, white arrows in the figure are attached to main parts that operate next from the state shown in the figure. The operation of the male part is as described above, and here, the operation of the drive mechanism at that time will be described in detail. Here, as shown in FIG. 6A, the state in which the center core 1, the main slide core 2, and the sub slide core 3 are combined to form the cavity C together with the cavity plate 101 is defined as an initial state. In this state, the resin melt | dissolved in the cavity C is poured, and the resin molded product P is shape | molded. When the resin is cured, the operation of the drive mechanism is started.

  First, the piston 4 moves backward by L1 (FIGS. 6A to 6B). Then, the back plate 5 integrated with the piston 4 and the center core 1 integrated with the back plate 5 also move backward by L1. The center core 1 escapes to the rear side through the insertion hole 202 of the stripper plate 201. Further, the back plate 5 comes into contact with the engagement piece 12a formed on the second pin 12 (a side view is shown on the right side of the overall view of FIG. 6B). L1 is a distance between the rear surface of the back plate 5 and the front surface of the engagement piece 12a of the second pin 12 in the initial state.

  Subsequently, the piston 4 moves backward by L2 (FIGS. 6B to 6C). Then, the back plate 5 and the center core 1 are also retracted by L2, and further, the engagement piece 12a is engaged with the back plate 5, whereby the second pin 12 is also retracted by L2. Along with this, the main slide core 2 connected to the second pin 12 via the sliding means 20 slides toward the inner peripheral side. Further, the back plate 5 comes into contact with an engagement piece 13a formed on the third pin 13 (shown in a side view on the lower left side of the overall view of FIG. 6C). L2 is the length in the front-rear direction of the guide groove of the second pin 12.

  Subsequently, the piston 4 is retracted by L3 (FIGS. 6C to 6D). Then, the back plate 5, the center core 1, and the second pin 12 are also retracted by L3, and further, the engagement piece 13a is engaged with the back plate 5, whereby the third pin 13 is also retracted by L3. Accordingly, the core plate 6 integrated with the third pin 13 is also retracted by L3, and the main slide core 2 mounted on the front surface of the core plate 6 is also retracted by L3. The head 2 a of the main slide core 2 escapes to the rear side through the insertion hole 202 of the stripper plate 201. Further, the core plate 6 abuts on the engaging piece 11a formed on the first pin 11 (a side view is shown on the upper left side of the overall view of FIG. 6 (d)). L3 is the distance between the rear surface of the core plate 6 and the front surface of the engagement piece 11a of the first pin 11 in the initial state.

  Subsequently, the piston 4 moves backward by L4 (FIGS. 6D to 6E). Then, the back plate 5, the center core 1, the second pin 12, the third pin 13, the core plate 6, and the main slide core 2 are also retracted by L 4, and the engaging piece 11 a is engaged with the core plate 6. The first pin 11 is also retracted by L4. Accordingly, the secondary slide core 3 connected to the first pin 11 via the sliding means 20 slides toward the inner peripheral side. L4 is the length of the guide groove of the first pin 11 in the front-rear direction. Thus, there is no portion engaged with the undercut portion U of the resin molded product P, and the resin molded product P can be removed.

  Subsequently, the operation of the drive mechanism when the center core 1, the main slide core 2 and the sub slide core 3 are joined from this state to return to the initial state where they can be molded again will be described in detail. First, the piston 4 moves forward by L5 (FIGS. 6E to 6F). Then, the back plate 5 integrated with the piston 4, the center core 1, the fifth pin 15, and the sixth pin 16 integrated with the back plate 5 also advance by L5. Accordingly, the second pin 12 and the third pin 13 connected to the fifth pin 15 and the sixth pin 16 via the connecting means 30 also advance by L5, and the core plate 6 integrated with the third pin 13 The main slide core 2 mounted on the front surface of the core plate 6 and the fourth pin 14 integrated with the core plate 6 also advance by L5. Accordingly, the first pin 11 connected to the fourth pin 14 via the connecting means 30 is also advanced by L5, and the auxiliary slide core 3 connected to the first pin 11 via the sliding means 20 is moved to the outer peripheral side. To slide. When the first pin 11 advances by L5, the through hole 32 of the first pin 11 and the outer hemispherical hole 31 of the housing 7 communicate with each other, and the sphere 34 rolls from the inner hemispherical hole 33 of the fourth pin 14 to the outer peripheral side. Since the connection between the first pin 11 and the fourth pin 14 is released, the first pin 11 does not advance any further. L5 is the length of the guide groove of the first pin 11 in the front-rear direction. Further, since the main slide core 2 and the second pin 12 advance simultaneously, the sliding means 20 interposed between them does not operate.

  Subsequently, the piston 4 moves forward by L6 (FIGS. 6 (f) to (g)). Then, the back plate 5, the center core 1, the fifth pin 15, the sixth pin 16, the second pin 12, the third pin 13, the core plate 6, and the main slide core 2 also advance by L6. The head 2 a of the main slide core 2 projects forward through the insertion hole 202 of the stripper plate 201. When the third pin 13 advances by L6, the through hole 32 of the third pin 13 and the outer hemispherical hole 31 of the housing 7 communicate with each other, and the sphere 34 rolls from the inner hemispherical hole 33 of the sixth pin 16 to the outer peripheral side. Since the connection between the third pin 13 and the sixth pin 16 is released, the third pin 13, the core plate 6, and the main slide core 2 do not advance any further. In addition, L6 is the length which the main slide core 2 returns to an initial position from a front state.

  Subsequently, the piston 4 moves forward by L7 (FIGS. 6G to 6H). Then, the back plate 5, the center core 1, the fifth pin 15, the sixth pin 16, and the second pin 12 also advance by L7. Along with this, the main slide core 2 connected to the second pin 12 via the sliding means 20 slides to the outer peripheral side. When the second pin 12 advances by L7, the through hole 32 of the second pin 12 and the outer hemispherical hole 31 of the housing 7 communicate with each other, and the sphere 34 rolls from the inner hemispherical hole 33 of the fifth pin 15 to the outer peripheral side. Since the connection between the second pin 12 and the fifth pin 15 is released, the second pin 12 does not advance any further. L7 is the length of the guide groove of the second pin 12 in the front-rear direction.

  Subsequently, the piston 4 moves forward by L8 (FIGS. 6H to 6A). Then, the back plate 5, the center core 1, the fifth pin 15, and the sixth pin 16 also advance by L8. The center core 1 projects forward through the insertion hole 202 of the stripper plate 201. Note that L8 is a length that the center core 1 returns to the initial position from the previous state. Thus, the center core 1, the main slide core 2 and the sub slide core 3 are joined to form the cavity C together with the cavity plate 101, and the resin molded product P can be molded again.

  The present invention is not limited to the above embodiment. Although the main slide core and the sub slide core are shown as being divided into four parts, they may be divided into three parts or six parts. In that case, the first to sixth pins, the sliding means and the connecting means are also adjusted accordingly. Increase or decrease. The undercut portion may be a recess formed on the inner surface of the hollow portion of the resin molded product. Further, the position of the undercut portion may be a front portion away from the stripper plate.

DESCRIPTION OF SYMBOLS 1 Center core 2 Main slide core 3 Sub slide core 4 Piston 5 Back plate 6 Core plate 7 Housing 11 1st pin 12 2nd pin 13 3rd pin 14 4th pin 15 5th pin 16 6th pin 20 Sliding means 21 Guide groove 22 Guide protrusion 30 Connecting means 31 Outer hemisphere hole 32 Through hole 33 Inner hemisphere hole 34 Sphere 40 Male mold part 50 Drive mechanism H Hollow part P Resin molded product U Undercut part

Claims (3)

A mold for injection molding of a resin molded product (P) having an undercut portion (U) on the inner surface of a hollow portion (H),
A male part (40) forming the hollow part (H), and a drive mechanism (50) for moving the male part (40),
The male part (40) is composed of a center core (1), a main slide core (2) and a sub slide core (3) alternately positioned on the outer periphery of the center core (1),
The drive mechanism (50) is located on the front side of the piston (4) moving forward and backward, the back plate (5) integral with the piston (4), and the back plate (5), and the main slide core ( 2) a core plate (6) that slides in the inner and outer circumferential directions, and a first plate (11), a second pin (12), a third plate located at the peripheral portions of the back plate (5) and the core plate (6). A pin (13), a fourth pin (14), a fifth pin (15) and a sixth pin (16), and a cylindrical housing (7) for accommodating them;
The fifth pin (15), the sixth pin (16) and the center core (1) are integral with the back plate (5), and the third pin (13) and the fourth pin (14) are the core plate (6). )
When the piston (4) moves backward,
The fifth pin (15), the sixth pin (16), the center core (1) and the back plate (5) retreat together with the piston (4);
Then, the second pin (12) engages with the back plate (5) and moves backward, and the sliding means (20) moves the main slide core (2) to the inner peripheral side,
Then the third pin (13) engages the back plate (5) and retracts, with the core plate (6) and the main slide core (2) retracting,
Next, the first pin (11) engages with the core plate (6) and moves backward, and the sliding means (20) moves the auxiliary slide core (3) to the inner peripheral side, so that the resin molded product (P) It can be removed,
When the piston (4) moves forward,
The fifth pin (15), the sixth pin (16), the center core (1) and the back plate (5) are advanced together with the piston (4), and the sixth pin (16) is moved to the third pin by the connecting means (30). The core plate (6), the main slide core (2), and the fourth pin (14) are moved forward together with the fifth pin (15) by the connecting means (30). The fourth pin (14) is connected to the first pin (11) by the connecting means (30) and advanced, and the first pin (11) is moved to the sliding means (20). After moving the auxiliary slide core (3) to the outer peripheral side by the connection, the connection of the fourth pin (14) and the first pin (11) is released by the connection means (30), and the advancement of the first pin (11) is stopped. And
Next, when the main slide core (2) reaches the front end, the connection of the sixth pin (16) and the third pin (13) is released by the connecting means (30), and the forward movement of the third pin (13) is stopped. At the same time, the advancement of the core plate (6) and the main slide core (2) is stopped,
Next, after the second pin (12) moves the main slide core (2) to the outer peripheral side by the sliding means (20), the fifth pin (15) and the second pin (12) are connected by the connecting means (30). The connection is released, the advancement of the second pin (12) stops,
Then, the center core (1) reaches the front end to enable molding of the resin molded product (P).   The sliding means (20) has a guide groove (21) inclined toward the inner peripheral side toward the front side formed in the first pin (11) and the second pin (12), the auxiliary slide core (3), and the main slide. The guide protrusion (22) protruding from the core (2) and engaging with the guide groove (21) of the first pin (11) and the second pin (12), respectively. Mold for injection molding.   The first pin (11), the second pin (12), and the third pin (13) are in sliding contact with the inner peripheral side surface of the housing (7), and the first pin (11), the second pin (12), and the first pin The fourth pin (14), the fifth pin (15), and the sixth pin (16) are in sliding contact with the inner peripheral side surface of the three pin (13), respectively, and the connecting means (30) is provided in the housing (7). An outer hemispherical hole (31) formed in the peripheral side surface, a through hole (32) formed in the inner and outer peripheral directions of the first pin (11), the second pin (12) and the third pin (13), and a fourth pin (14) The inner hemispherical hole (33) formed on the outer peripheral side surfaces of the fifth pin (15) and the sixth pin (16), the outer hemispherical hole (31), the through hole (32), and the inner hemispherical hole (33) A ball (34) that rolls inside, a first pin (11), a fourth pin (14), and a second pin (12) The fifth pin (15), the third pin (13) and the sixth pin (16) are connected to each other through the through holes (32) and the inner hemispherical holes (33), and the pins are connected to each other. The outer hemispherical hole (31) and the first pin (11), the second pin (12), and the through hole (32) of the third pin (13) communicate with each other to release the connection between the pins. The injection mold according to claim 1 or 2.

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