JP5905787B2 - Injection mold - Google Patents

Description

  The present invention relates to an injection mold for easily changing the color of a molded product.

  Conventionally, a hot liner system has been used as a means of efficiently producing molded products by filling molten resin into the mold cavity, and the resin in the passage from the sprue to the hot runner and gate has always been used. A molded product is manufactured by filling a cavity with a molten resin from a gate while maintaining a molten state.

  On the other hand, in recent years, when it is desired to produce interior materials of different colors, such as automobile interior materials, for example, black interior materials and white interior materials, the black heat melted from the nozzles of the molding unit. After filling the mold cavity with a plastic resin (hereinafter simply referred to as a molten resin), the mold cavity is filled with white molten resin from the nozzle of the molding unit using the mold. Or by filling the mold cavity with white molten resin and then filling the mold cavity with black molten resin from the nozzle of the molding unit using this mold, Production of molded articles of different colors has been performed.

  In this case, in the molten resin of any color, since the molten resin of that color exists in the passage from the sprue to the hot runner, the gate, when manufacturing a molded product of a different color, that is, When changing colors, it is necessary to make trial shots from the nozzle of the molding unit many times to completely change the color of the molded product. It will take some time before the replacement can be done completely.

  For this reason, as described in Patent Document 1, a hot runner block having two hot runners inside is combined with a mold so that the sprue of one hot runner faces the nozzle of the molding unit. When a mold of a predetermined color is manufactured by fixing a mold and supplying a molten resin of a predetermined color into one hot runner through its sprue, A hot runner configured to produce a molded product of a predetermined color by suspending the mold by a crane or the like and fixing the mold so that the sprue of the other hot runner in the hot runner block faces the nozzle of the molding unit. Mold color changer has been developed.

  Further, in Patent Document 2, a hot runner block having two hot runners inside is mounted on a mold, and two hot resins are introduced onto the hot runner block from a nozzle of an injection unit. When a nozzle touch block having an introduction port provided at a predetermined interval is movably disposed, and when this nozzle touch block is moved and one of the introduction ports is positioned immediately below the nozzle of the injection unit, The injection port communicates with one of the hot runners, and a molten resin is filled into the cavity from the hot runner through the gate provided on the back side of the mold, thereby producing a molded product of a predetermined color. When the other inlet is positioned directly under the nozzle of the injection unit by moving from the position, the inlet is connected to the other hot runner. A molded product having a different color from the above is manufactured by filling the cavity with a molten resin having a color different from the color of the molten resin through a gate different from the gate provided on the mold back side from the hot runner An injection mold configured as described above is described.

JP 2007-062085 A JP 2010-137521 A

  However, according to the former hot runner mold color changing device, when changing the color of a molded product, it is necessary to move the entire mold using a crane or the like. In addition to requiring labor and labor, there is a problem in that a crane or the like is required for loading and installation.

  On the other hand, according to the latter injection mold, the color can be changed easily and reliably by moving the nozzle touch block on the hot runner block without moving the mold. Since the gates communicating with the outlet sides of the two hot runners provided inside each face the cavity, filling the cavity with molten resin from one hot runner through the gate communicating with the hot runner This molten resin flows into the gate communicated with the other hot runner side.

  The gate opening / closing means facing the cavity generally has a resin passage in which the upper end communicates with the outlet of the hot runner and the gate is provided at the lower end, and a gate pin is provided at the center of the resin passage. There is known a valve body configured such that the gate is closed by the lower end of the gate pin by inserting the valve body movably in the length direction of the resin passage, and there are a plurality of valve bodies corresponding to each hot runner. When installed in the mold, the interval between the valve body having a resin passage communicating with one hot runner and the valve body having the resin passage communicating with the other hot runner is widened, and the lower ends of these resin passages The distance between the gates facing the cavity cannot be reduced.

  When injection molding of different colored parts with the same structure, if the position where the injection filling from the one gate into the cavity is greatly shifted from the position where the injection filling from the other gate into the cavity, the molding with the same structure Despite being a product, there is a risk of unevenness in strength, and even though it is desirable that the injection trace from the gate be provided in a portion that is difficult to see from the outside in the molded product, It is difficult for both gates to face the cavity for molding the portion, and there is a possibility that a molded product having a different color with a good appearance cannot be obtained.

  The present invention has been made in view of such problems, and the object of the present invention is to easily perform color change when manufacturing a molded product of a different color by injection molding and efficiently manufacture it. Of course, it is possible to narrow the interval between the gates for injecting and filling molten resin of different colors into the cavities, and to obtain a molded product having a uniform strength. An object of the present invention is to provide an injection mold that can be provided in a difficult part.

  In order to achieve the above object, an injection mold according to the present invention is provided on a fixed mold and includes a plurality of independent hot runners inside as described in claim 1. A hot runner block that faces the nozzles of the molding unit at different positions that are offset from the nozzles of the molding unit, and a plurality of hot runner blocks that respectively correspond to the plurality of hot runners. Nozzle touch block which has an inlet and is slidably disposed on the hot runner block and communicates with the inlet of the hot runner corresponding to the inlet through the inlet which has just reached the nozzle of the molding unit. And arranged in parallel in the fixed mold, with the upper ends communicating with the outlets of the plurality of hot runners and the lower ends at the gates. Through comprising a plurality of resin passage communicating with the cavity, and, characterized in that it is inserted respectively into these resin passage is composed of a valve body formed by providing a valve pin for opening and closing the gate.

  In the injection mold thus configured, the invention according to claim 2 is characterized in that one heat insulation ring is attached to the upper end portion of the valve body in which the resin passages into which the valve pins are inserted are arranged side by side. And a heat band is attached to the outer peripheral surface of the valve body.

  According to a third aspect of the present invention, the valve body is divided into a plurality of parts and one resin passage into which each valve pin is inserted is provided in each divided valve body, and a heat band is attached to the outer peripheral surface of each divided valve body In addition, these divided valve bodies are bundled in a uniform manner, and one heat insulating ring is attached to the upper end of the divided valve bodies so as to surround these divided valve bodies.

  Furthermore, the invention according to claim 4 is characterized in that a single common passage is provided through a short extension passage at the lower end gate of the plurality of resin passages arranged side by side, and the common passage communicates with the cavity. To do.

  In the invention according to claim 5, the interval between the valve pins in the adjacent resin passages is made smaller than the diameter of the cylinder for operating these valve pins installed on the hot runner block, while The outer end portions of the support pieces are fixed to the rods of the cylinder, the inner end portions of these support pieces are opposed to each other in a close state, and the heads of the above-described valve pins are connected to and supported by the inner end portions, respectively. Features.

  According to a sixth aspect of the present invention, a fixed base provided with a plurality of hot runner inlets is disposed on the upper surface of the hot runner block, and guide members are arranged side by side at fixed intervals on the fixed base. In addition, a nozzle touch block is disposed between these guide members so as to be reciprocally movable in the length direction of the guide member, and a straight flange portion having a certain width is provided above the opposite end portion of the guide member. The upper surface of the engaging flange projectingly provided on the lower surface of the nozzle touch block is slidably engaged with the lower surface of the flange touch block, and is engaged with the lower surfaces of these straight flanges. Convex portions are provided at regular intervals in the length direction on the upper surface of the flange portion, and when the introduction port is positioned directly below the nozzle of the molding unit by the movement of the nozzle touch block, the straight flange portion of the guide member is On the bottom The nozzle touch block is configured to be pressed onto the fixed base by causing the convex portion provided on the upper surface of the engagement flange portion of the nozzle touch block to ride on the convex portion. The plate-like support member is detachably fixed to the upper surface of the projecting portion with a bolt.

  Further, the invention according to claim 7 is provided with a position detection sensor that detects the position of the introduction port when the nozzle touch block is moved and is located immediately below the nozzle of the molding unit to stop the movement of the nozzle touch block. It is characterized by having installed.

  According to the first aspect of the invention, the nozzle touch block having a plurality of inlets corresponding to each of the hot runners is slid on the hot runner block having a plurality of independent hot runners therein. Then, by making the desired introduction port face the nozzle of the molding unit, this introduction port can be communicated with a predetermined hot runner provided in the hot runner block and installed in the fixed mold through this hot runner. The molten resin can be injected and filled into the cavity from the lower end gate through a predetermined resin passage in the valve body. Therefore, when manufacturing molded products of different colors, the nozzle touch block is moved. Without having to test drive by making the inlet corresponding to the color opposite the nozzle of the molding unit It is possible to perform single and securely color change.

  Further, the valve body mounted in the fixed mold is provided with a plurality of resin passages whose upper ends communicate with the outlets of the plurality of hot runners and whose lower ends communicate with the cavities through the gates. Since the valve pin for opening and closing the gate is provided by being inserted into each of the resin passages, the molten resin is supplied from the gate at the lower end of the resin passage to the cavity through one resin passage communicating with the hot runner from the desired hot runner. When injection molding is performed, it is possible to reliably prevent the molten resin from entering the other resin passages by closing the other molten resin gates. Because the resin passages are bundled together, the valve body can be mounted in one hole in the fixed mold. In addition, the structure can be simplified and the mold can be easily manufactured. In addition, the gap between the gates of the adjacent resin passages can be narrowed. From the gate, the position where the injection filling into the cavity can be brought close to the position where the injection filling from the other gate is performed. The injection mark can be provided on the part of the molded product that is difficult to see from the outside, and a molded product having a good appearance can be obtained.

  According to the second aspect of the present invention, since one heat insulating ring is attached to the upper end portion of the valve body in which the resin passages into which the valve pins are inserted are arranged side by side, the hot runner block at the time of molding is mounted. Heat can be prevented from being transferred to the fixed mold, and a heat band is attached to the outer peripheral surface of the valve body, so that the resin passage can be heated by this heat band when changing colors. The structure can be simplified.

  On the other hand, according to the invention according to claim 3, the valve body is divided into a plurality of parts, and one resin passage into which each valve pin is inserted is provided in each divided valve body. A heat band is attached and these split valve bodies are bundled together and one heat insulating ring is attached to the upper end of the split valve body so as to surround these split valve bodies. While being bundled by a ring, it can be mounted in one hole of the fixed mold as described above, and only the resin passage to be used can be heated by a heat band.

  Furthermore, according to the invention according to claim 4, since one common passage is provided through an extended passage having a short length at the lower end gates of the plurality of resin passages arranged side by side, and the common passage communicates with the cavity. Even if the color is changed, the position of injection filling into the cavity from the bottom gate of any resin passage is always one place. Therefore, the strength of the color-changed molded product can be made uniform and the injection mark can be seen from the outside. A molded product having an excellent appearance and good appearance can be obtained because it can be reliably provided in a difficult part.

  According to the invention of claim 5, the interval between the valve pins in the adjacent resin passages is narrower than the diameter of the operating cylinders of these valve pins installed on the hot runner block. The outer end portions of the support pieces are fixed to the rods of the operating cylinders, the inner end portions of these support pieces are opposed to each other in a close state, and the heads of the above-described valve pins are connected to and supported by the inner end portions, respectively. Therefore, despite the fact that multiple valve pin operating cylinders are installed on the hot runner block, the distance between adjacent valve pins can be set as narrow as possible below the diameter of the valve pin operating cylinder. When injection molding a molded product, as described above, injection filling from one gate into the cavity and injection filling from the other gate That position and no intensity irregularity and color change to be able to close the, and can be injection traces obtained a molded article hardly seen from the outside.

  According to the sixth aspect of the present invention, a fixed base provided with a plurality of hot runner inlets is disposed on the upper surface of the hot runner block, and guide members are arranged side by side on the fixed base at regular intervals. The engaging flange portions projecting on both lower portions of the nozzle touch block are slidably contacted to the lower surface of the straight flange portion projecting at the upper portion of the opposite end portions of these guide members. Since the nozzle touch block is configured to move along the guide member, by moving the nozzle touch block back and forth along the guide member, the desired molten resin inlet port is changed to a hot runner corresponding to the inlet port. It is possible to communicate easily and reliably.

  In addition, convex portions are provided at regular intervals in the length direction on the lower surface of the straight flange portion of the guide member and the upper surface of the engagement flange portion of the nozzle touch block. Is positioned directly below the nozzle of the molding unit, the convex portion provided on the upper surface of the engagement flange portion of the nozzle touch block is mounted on the convex portion provided on the lower surface of the straight flange portion of the guide member. Since the nozzle touch block is configured to be pressed onto the fixed base, the lower surface of the nozzle touch block can be firmly and uniformly crimped over the entire surface without causing a gap in the upper surface of the fixed base during injection molding. It is possible to perform injection molding without leaking molten resin, and more than three inlets are provided in a straight line on the nozzle touch block. Each time each inlet is moved directly below the nozzle of the injection unit, a convex portion provided on the upper surface of the engaging flange portion of the nozzle touch block is provided on the convex portion provided on the lower surface of the straight flange portion of the guide member. It is possible to perform injection molding while getting on and pressing the nozzle touch block firmly on the fixed base.

  According to the seventh aspect of the present invention, when the introduction port is located immediately below the nozzle of the molding unit due to the movement of the nozzle touch block, a position detection sensor that detects the position and stops the movement of the nozzle touch block is provided. Therefore, a desired introduction port can be automatically and accurately positioned directly under the nozzle of the molding unit.

The simplified longitudinal front view of the whole injection mold. The top view of a hot runner block part. Sectional drawing for demonstrating the relationship between the two inlets of a nozzle touch block, and the two resin channel | paths in the valve | bulb main body connected to these inlets. The longitudinal section front view in the 1st sprue bush part on a nozzle touch block. The longitudinal section front view in the 2nd sprue bush part on a nozzle touch block. The perspective view of the nozzle touch block arrange | positioned on a fixed base. The disassembled perspective view of a nozzle touch block and a guide member. The perspective view of the hydraulic cylinder for a movement of a nozzle touch block. The simplified vertical side view of the state which made the nozzle touch block crimp to the fixed base. The front view of a valve body. The front view of a division | segmentation valve main body.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 to 5, an injection mold is arranged with a fixed mold 1 and a movable mold 2 facing each other up and down. A cavity 3 for obtaining a molded product is formed between the opposing surfaces of the molds 1 and 2, and a hot runner block 4 is disposed and fixed on the fixed mold 1.

  In the hot runner block 4, two hot runners, a first hot runner 5 and a second hot runner 6, are provided in parallel in the horizontal direction and independent from each other with a small interval in the vertical direction. In addition, one end openings of the first and second hot runners 5 and 6 are faced upward from the upper surface of the hot runner block 4 with a certain distance from each other at the center of the hot runner block 4. A fixed base 7 made of a flat rectangular plate having a certain thickness is fixed to the upper surface of the central portion of the hot runner runner block 4 provided with the opening, and the first and second hot hot runner blocks 4 are fixed to the fixed base 7. First and second holes are formed through the upper and lower surfaces of the runners 5 and 6 so that the upper end faces the upper end of the fixed base 7 upwardly. Hotra Inlet 5a of the Na 5,6, are formed respectively in 6a.

  The inlet 5a of the first hot runner 5 is provided at a position spaced apart from one side with respect to the center in the width direction of the fixed base 7, and the inlet 6a of the second hot runner 6 is The fixed base 7 is provided at a position spaced apart from the center in the width direction on the other side.

  At the both ends of the upper surface of the fixed base 7, square bar-shaped guide members 8, 8 are fixed in parallel to each other at a constant interval in the width direction of the fixed base 7, and these guide members 8, 8 A nozzle touch block 9 having a first sprue bushing 10 and a second sprue bushing 11 projecting at a predetermined interval in the length direction at a central portion in the width direction on the upper surface is provided between the guide members 8 and 8. Are arranged so as to be able to reciprocate along.

  Specifically, as shown in FIG. 4 to FIG. 7, straight flange portions 8 a and 8 a having a constant width over the entire length project from the upper portions of the opposite side end portions of the both side guide members 8 and 8. On the other hand, the nozzle touch block 9 has a certain width that is inserted into the space below the straight flange portions 8a and 8a at the lower portions on both sides and the upper surface thereof is in sliding contact with the lower surfaces of the straight flange portions 8a and 8a. Straight engaging flange portions 9a, 9a are provided in a projecting manner, and the engaging flange portions 9a, 9a are engaged with the straight flange portions 8a, 8a in the longitudinal direction of the guide members 8, 8 on both sides. The nozzle touch block 9 is configured to slide.

  As shown in FIG. 4, the sprue 10a provided in the first sprue bushing 10 has its upper end opening opened upward at the center of the sprue bushing 10 and one side downward from the upper end opening. Furthermore, the lower end of the inclined passage is communicated with the upper end of an inclined passage 12 ′ formed in one side portion of the nozzle touch block 9 below the first sprue bush 10. When the first sprue bushing 10 is positioned below the nozzle a of the injection unit A by the movement of the nozzle touch block 9 as will be described later, the lower end of the inclined passage 12 'is brought into the inlet 5a of the first hot runner 5. It is configured to communicate. A passage from the upper end of the opening of the sprue 10a to the lower end of the inclined passage 12 'provided in the nozzle touch block 9 is formed in the first introduction port 12 of the molten resin.

  Similarly, the sprue 11a provided in the second sprue bushing 11 has its upper end opening opened upward at the center of the sprue bushing 11 as shown in FIG. The first sprue bush 10 is inclined to the other side opposite to the sprue 10a, and the lower end of the inclined passage is further below the second sprue bush 11 on the other side of the nozzle touch block 9. The second sprue bush 11 is connected to the upper end of the inclined passage 13 'drilled in the nozzle, and the lower end of the inclined passage 13' is moved by the nozzle touch block 9 as will be described later. When it is positioned below a, it is configured to communicate with the inlet 6a of the second hot runner 6. A passage from the upper end of the opening of the sprue 11a to the lower end of the inclined passage 13 'provided in the nozzle touch block 9 is formed in the second introduction port 13 of the molten resin.

  Further, when the molten resin is introduced from the nozzle a of the injection unit A to the inlet 5a of the first hot runner 5 through the sprue 10a of the first sprue bush 10, the second sprue bush 11 is injected from the nozzle a of the injection unit A. When the molten resin is introduced into the inlet 6a of the second hot runner 6 through the sprue 11a, a gap is generated between the lower surface of the nozzle touch block 9 and the upper surface of the fixing base 7 that opens the inlets 5a and 6a. If there is, there is a possibility that the molten resin leaks from the gap. Therefore, during injection molding, the nozzle touch block 9 is pressed against the hot runner block 4 and the lower surface of the nozzle touch block 9 is pressed against the upper surface of the fixed base 7 without any gap. A crimping means 14 is provided.

  As shown in FIGS. 4 to 7 and 9, the crimping means 14 includes a lower surface of the straight flange portions 8a and 8a of the guide members 8 and 8, and a nozzle touch block 9 that engages with the lower surface. A plurality of very thin convex portions 8b, 9b each having a flat top surface with a height of about several tens of microns at regular intervals in the length direction are protruded from the upper surfaces of the engaging flange portions 9a, 9a. On the convex portion 8b projecting from the lower surface of the straight flange portion 8a of the guide members 8, 8, the convex portion 9b projecting from the upper surface of the engagement flange portion 9b of the nozzle touch block 9 rides on each other. When the top surfaces are brought into pressure contact with each other, the nozzle touch block 9 is pushed downward by a minute height corresponding to the sum of the heights of the convex portions 8b and 9b, and the lower surface of the nozzle touch block 9 is moved down. By firmly pressing against the fixed base 7, the gap is eliminated.

  As described above, the pressure contact between the convex portions 8b and 9b is when the first sprue bush 10 or the second sprue bush 11 is positioned below the nozzle a of the injection unit A. At this time, the convex portion 8b , 9b is at least two press contact points, and the formation interval and the number of these convex portions 8b, 9b are set so as to occur. Specifically, when the length direction of the nozzle touch block 9 is the front-rear direction, as shown in the figure, the lower surface of the straight flange portion 8a of the guide member 8 includes two portions at the front and rear end portions and the intermediate portion. On the other hand, the convex portions 8b are projected at intervals longer than the length of the convex portion 8b, while the engaging flange portion 9a of the nozzle touch block 9 is projected on the straight flange portion 8a. The convex portions 9a having a shorter length than the convex portions 8b are provided at three positions, that is, the front and rear end portions and the central portion at every same interval between the convex portions 8b and the central portion in the length direction.

  Accordingly, when the first sprue bush 10 is positioned below the nozzle a of the injection unit A, as shown in FIG. 9, the three convex portions projecting from the upper surface of the engaging flange portion 9a of the nozzle touch block 9 The nozzle touch block 9 is mounted on the fixed base 7 so that the front end side protruding portion 8b and the protruding portions 8b and 8b at the two intermediate portions overlap each other with the protruding portion 8b protruding from the lower surface of the straight flange portion 8a of the guide member 8 Similarly, when the second sprue bushing 10 is positioned below the nozzle a of the injection unit A, the above three convex portions 9b of the engagement flange portion 9a of the nozzle touch block 9 are guided by the guide member. The nozzle touch block 9 is entirely placed on the fixed base 7 so as to overlap the convex portions 8b and 8b at the two intermediate portions projecting from the lower surface of the straight flange portion 8a of 8 and the convex portion 8b on the rear end side. Press evenly.

  Further, when the first and second sprue bushes 10 and 11 are moved toward the lower side of the nozzle a of the injection unit A, the convex portion 9b provided on the upper surface of the engagement flange portion 9a of the nozzle touch block 9 is A convex portion 8b provided on the lower surface of the straight flange portion 8a of the guide member 8 in sliding contact with the lower surface of the smooth concave portion between the adjacent convex portions 8b, 8b provided on the lower surface of the straight flange portion 8a of the guide member 8. Moves while sliding on the lower surface of the smooth concave portion between the adjacent convex portions 9b, 9b provided on the upper surface of the engaging flange portion 9a of the nozzle touch block 9.

  A switching hydraulic cylinder 15 for reciprocating the nozzle touch block 9 in the front-rear direction is disposed on the fixed mold 1 so as to face the rear of the nozzle touch block 9. The front ends of the 15 piston rods 15a are connected to the center of the rear end surface of the nozzle touch block 9.

  As shown in FIGS. 2, 3 and 8, the connecting structure has an insertion groove 16a having a constant width and depth from the center of the rear end surface to the front, and the groove width is in communication with the insertion groove 16a. A connecting piece 16 having a locking groove 16b wider than the groove 16a is fixed to the rear end of the nozzle touch block 9, and the tip of the piston rod 15a is inserted into the insertion groove 16a of the connecting piece 16 from above. On the convex portion 8b projecting on the lower surface of the straight flange portion 8a of the guide members 8 and 8, the large-diameter head portion of the piston rod 25a is engaged with the locking groove 16b so that the top portion 15b can be moved up and down. In addition, the protrusion 9b protruding from the upper surface of the engagement flange 9b of the nozzle touch block 9 is allowed to get on and release the ride, and the nozzle touch block 9 is allowed to slightly move in the vertical direction. It is configured so that the operation can be performed smoothly.

  Further, the nozzle touch block 9 is slid in the front-rear direction on the fixed base 7 by the operation of the switching hydraulic cylinder 15, and the nozzle touch is made on the lower surface convex portion 8b of the straight flange portion 8a of the both side guide members 8, 8. The upper surface convex portion 9b of the engagement flange portion 9a of the block 9 rides on, and the upper end of the first introduction port 12 reaches below the nozzle a of the injection unit A, and the lower end communicates with the inlet 5a of the first hot runner. When the upper surface convex portion 9b of the engaging flange portion 9a of the nozzle touch block 9 rides on the lower surface convex portion 8b of the straight flange portion 8a of the both side guide members 8, 8, and the upper end of the second introduction port 13 When a nozzle a of the injection unit A reaches below the lower end and the lower end communicates with the inlet 5a of the second hot runner, a position detection sensor 17 for detecting the respective positions and stopping the operation of the hydraulic cylinder 15 is provided. Yes.

  As shown in FIGS. 1 and 2, the first and second hot runners 5 and 6 provided in the hot runner block 4 extend from the central portion of the hot runner block 4 to both sides, and have respective outlets 5b. 6b are respectively communicated with the upper ends of the first and second resin passages 19 and 20 arranged in parallel in the valve body 18 provided at a plurality of locations of the fixed mold 2.

  Each valve body 18 is mounted vertically in the fixed mold 1, and its upper end surface is brought into close contact with the lower surface of the hot runner block 9, and the first and second resin passages 19. The first and second gates 21 and 22 communicating with each other in the cavity 3 formed by clamping the fixed mold 1 and the movable mold 2 are formed at the lower end portions of 20 and 20, respectively. The lower ends of the first and second gates 21 and 22 may be directly communicated with the cavity 3, but in this embodiment, an extended short passage is formed at the lower ends of the first and second gates 21 and 22. The upper ends of 21a and 22a are communicated with each other, the lower ends of these extended short passages 21a and 22a are communicated with one common passage 23, and the lower end of the common passage 23 is communicated with the cavity 3. The first and second gates 21, 22 and the extended short passages 22a, 22b and the common passage 22 are formed to have a smaller diameter than the diameters of the first and second resin passages 19, 20.

  In the figure, 24 and 25 are gate bushes, 26 is a heat band attached so as to surround the valve body 18 and the gate bushes 24 and 25, and 27 is a heat cover. 28 is a heat insulating ring which is attached to the outer peripheral surface of the upper end portion of the valve body 18, and the upper end surface thereof is in close contact with the lower surface of the hot runner block 4 together with the upper end surface of the valve body 18, and the lower end portion is the upper end of the fixed mold 1 The heat is transferred from the hot runner block 4 to the fixed mold 1 by being embedded in the section.

  First and second valve pins 29 and 30 that open and close the first and second gates 21 and 22 by their lower ends are inserted into the central portions of the first and second resin passages 19 and 20 so as to be movable up and down. The upper end portions of these valve pins 29 and 30 are slidably passed through the hot runner block 4 in the vertical direction so that the upper end portion protrudes upward from the upper surface of the hot runner block 4 and the protruding tip portion is installed. It is connected to rods 31a and 32a of the first and second hydraulic cylinders 31 and 32 installed side by side on the table 33 and moved up and down by the operation of these first and second hydraulic cylinders 31 and 32. The first and second gates 21 and 22 are configured to open and close at the respective lower ends. In addition, the installation base 33 is formed of a leg 33a standing on the hot runner block 4 from a heat insulating material, and heat of the hot runner block 4 is transmitted to the first and second hydraulic cylinders 31 and 32. Is shut off.

The first and second resin passages 19 and 20 are preferably arranged side by side so as to be as close as possible to each other. By doing so, the diameter of the valve body 18 is reduced, and the valve body 18 is inserted. A hole drilled in the hot runner 4 for wearing can be made small in diameter. In addition, in order to improve the appearance of the molded product, the first and second portions are formed in a part of the cavity for molding the concave portion corresponding to a portion that is difficult to see from the outside, for example, the concave portion. When the molten resin is introduced into the cavity 3 from the extension passages 21a and 22a through the common passage 23 as described above, the extension passages 21a and 22a can be formed.
Therefore, the mold can be easily opened after injection.

  At this time, the width between the first and second resin passages 19 and 20 is narrowed, and the distance between the first and second valve pins 29 and 30 inserted in these resin passages is changed to the first and second hydraulic cylinders. When the outer diameter of the first and second valve pins 29 and 30 is made smaller than the outer diameter of the first and second valve pins 29 and 30, a part of the first and second hydraulic cylinders 31 and 32 are overlapped on the installation base 33. In the embodiment of the present invention, the width interval between the first and second valve pins 29 and 30 is smaller than the outer diameter of the hydraulic cylinders 31 and 32, respectively. The hydraulic cylinders 31 and 32 are configured to be movable up and down.

  That is, as shown in FIG. 3, the first and second hydraulic cylinders 31 and 32 are installed on the installation base 33 in a state where the distance between the centers thereof is set equal to or larger than the cylinder diameter. The outer ends of the support pieces 34a and 34b are fixed to the rods 31a and 32a protruding downward from the centers of the first and second hydraulic cylinders 31 and 32, respectively, while the inner ends of the support pieces 34a and 34b are fixed to the rods 31a and 32a. The heads of the first and second valve pins 29 and 30 are supported on the inner ends thereof so as to face each other in an approaching state. Further, as shown in the figure, the pin head supporting portion at the inner end portion is formed in a U-shape so that the pin heads can approach and separate from each other, and the hot runner block 4 is expanded by heating to be first. The upper end portions of the second valve pins 29 and 30 are configured to horizontally move the head in the support portion in the direction of approaching and separating in accordance with the amount of variation due to heat to absorb the variation amount.

  In order to form a molded product of different colors, for example, a white molded product and a black molded product, using the injection molding die configured as described above, the nozzle touch block 9 is erected. One of the sprues 10a and 11a of the first and second sprue bushes 10 and 11, for example, the first sprue bush 10 side is set for a black molded product, and the second sprue bush 11 side is set for a white molded product. .

  Then, when obtaining a black color molded product, the switching hydraulic cylinder 15 is operated to move the nozzle touch block 9 along the guide members 8 and 8 on both sides, and the first sprue erected on the upper surface thereof. The sprue 10a of the bush 10 is positioned directly below the nozzle a of the injection unit A. At this time, the movement of the nozzle touch block 9 is detected by the position detection sensor 17, and when the sprue 10a of the first sprue bush 10 is located immediately below the nozzle a of the injection unit A, the operation of the switching hydraulic cylinder 15 is stopped.

  In this state, the first inlet 12 formed by the passage from the sprue 10a of the first sprue bush 10 to the lower end of one inclined passage 12 'in the nozzle touch block 9 communicating with the sprue 10a. As shown in FIGS. 3 and 4, the lower end communicates with the inlet 5 a of the first hot runner 5 provided in the hot runner block 4. Further, a convex portion 9b provided on the upper surface of the engagement flange portion 9a of the nozzle touch block 9 is provided on at least two convex portions 8b, 8b provided on the lower surface of the straight flange portion 8a of the both side guide members 8, 8. It rides on and presses the nozzle touch block 9 evenly downward and crimps it onto the fixed base 7 without any gaps.

  Further, the first valve pin 29 inserted into the first resin passage 19 communicating with the first hot runner 5 in the hot runner block 4 in all the valve main bodies 18 arranged at several places of the fixed mold 1. Is moved upward by the first hydraulic cylinder 31 to open the first gate 21, while the second valve pin 30 inserted into the second resin passage 20 communicating with the second hot runner 6 is lowered by the second hydraulic cylinder 32. The second gate 22 is closed by moving it.

  In this state, when the nozzle a of the molding unit A is pressed against the sprue 10a of the first sprue bushing 10 and the molten resin colored black is injected into the first inlet 12 through the sprue 10a, the molten resin is first introduced. The first hot runner 5 enters the first hot runner 5 from the inlet 5a of the first hot runner 5 communicated with the first introduction port 12 through the port 12, and further, the first resin in the valve body 18 from the outlet 5b of the first hot runner 5 It is introduced into the upper end of the passage 19 and passes through the common passage 23 from the first gate 21 at the lower end of the first resin passage 19 through the extension passage 21a and is filled into the cavity 3, and a black molded product is injection molded.

  Next, when obtaining a white molded product, the switching hydraulic cylinder 15 is operated to move the nozzle touch block 9 along the guide members 8 and 8 on both sides, and as shown in FIG. The sprue 11a of the second sprue bush 11 is positioned directly below the nozzle a of the injection unit A. The position detection sensor 17 detects that this position has been reached, and the operation of the switching hydraulic cylinder 15 is stopped.

  When the second sprue bushing 11 is located immediately below the nozzle a of the injection unit A, this time, the other inclined passage 13 'in the nozzle touch block 9 communicating with the sprue 11a from the sprue 11a of the second sprue bushing 11 is this time. The lower end of the second introduction port 13 formed by the passage to the lower end of the second end communicates with the inlet 6 a of the second hot runner 5 provided in the hot runner block 4. In this state, the projections provided on the upper surface of the engagement flange portion 9a of the nozzle touch block 9 on the at least two projections 8b, 8b provided on the lower surface of the straight flange portion 8a of the both side guide members 8, 8. The part 9b rides on and presses the nozzle touch block 9 evenly downward and presses the nozzle touch block 9 onto the fixed base 7 without any gap.

  Further, the first valve pin 29 inserted into the first resin passage 19 communicating with the first hot runner 5 in the hot runner block 4 in all the valve main bodies 18 arranged at several places of the fixed mold 1. Is moved downward by the first hydraulic cylinder 31 to close the first gate 21, while the second valve pin 30 inserted into the second resin passage 20 communicating with the second hot runner 6 is raised by the second hydraulic cylinder 32. The second gate 22 is opened by moving.

  In this state, the nozzle a of the molding unit A is pressed against the sprue 11a of the second sprue bush 11, and molten resin colored in white is injected into the second inlet 13 through the sprue 11a. The second hot runner 6 enters the second hot runner 6 from the inlet 6a of the second hot runner 6 communicated with the second introduction port 13 through the port 13, and the second resin in the valve body 18 from the outlet 6b of the second hot runner 6 further. It is introduced into the upper end of the passage 20 and passes through the common passage 23 from the second gate 22 at the lower end of the second resin passage 20 through the extension passage 22a to fill the cavity 3, and a white molded product is injection molded.

  In the above embodiment, the first and second resin passages 19 and 20 into which the first and second valve pins 29 and 30 are respectively inserted are arranged in parallel in the common valve body 18. The heat insulation ring 28 is attached to the upper end portion of the valve body 18 and the heat band 26 is attached to the outer peripheral surface of the valve body 18, but as shown in FIG. There is one resin passage into which the valve pin is inserted in the divided valve main body 18a, and a heat band 26a is attached to the outer peripheral surface of each divided valve main body 18a, and these divided valve main bodies 18a are bundled together in an aligned manner. Alternatively, one heat insulating ring 28a may be attached to the upper end of the lever so as to surround the divided valve main body 18a.

  Further, in the above-described embodiment, the structure of the injection mold that can obtain two different color molded products such as white and black has been described. However, three or more sprue bushes are provided on the nozzle touch block 9. The hot runner block 4 is provided with a plurality of hot runners communicating with the sprue bushes, and a plurality of resins openable and closable by valve pins respectively communicating with the outlets of the hot runners. The present invention can be satisfied even with an injection mold structure in which a large number of colors can be changed by mounting a valve body provided with a passage in the fixed mold 1.

  In this case, the nozzle touch block 9 that can be reciprocated in the front-rear direction while being guided by the guide members 8 and 8 is lengthened, and three or more sprue bushes are erected on the upper surface at regular intervals. However, it is formed on the lower surface of the straight flange portion 8a of the both side guide members 8 and 8 and the upper surface of the engagement flange portion 9a of the nozzle touch block 9 which are elongated according to the length of the nozzle touch block 9. When a desired sprue bush is positioned directly under the nozzle a of the unit A, a plurality of convex portions 8b and 9b that press the nozzle touch block 9 downward are provided at regular intervals according to the number of sprue bushes. However, if the number of resin passages in the valve body provided corresponding to the number of sprue bushings increases, the position of injection from the respective gates into the cavities greatly deviates. To eliminate this, it is desirable to disposed in a bundled state of the 2-4 of the resin passage.

DESCRIPTION OF SYMBOLS 1 Fixed mold 3 Cavity 4 Hot runner block 5, 6 1st and 2nd hot runner 7 Fixing base 8, 8 Guide member
8a, 8a Straight flange
8b Convex part 9 Nozzle touch block
9a, 9a Engagement flange
9b Convex
10, 11 First and second sprue bushings
12, 13 First and second inlets
14 Crimping means
15 Hydraulic cylinder
17 Position detection sensor
18 Valve body
19, 20 First and second resin passages
21, 22 First and second gate
28 Insulation ring
29, 30 1st and 2nd valve pins
31, 32 First and second hydraulic cylinders
34 Support strip

Claims (7)

  A plurality of hot runners arranged on a fixed mold and independent from each other are provided, and the nozzles of the molding units are respectively located at different positions in which the inlets of these hot runners are offset from directly below the nozzle of the molding unit. And a plurality of inlets corresponding to each of the plurality of hot runners, and is slidably disposed on the hot runner block so that the nozzles of the molding unit A nozzle touch block that communicates the inlet that has reached directly below with the inlet of the hot runner corresponding to the inlet, and a juxtaposed arrangement in the fixed mold, with the upper ends at the outlets of the plurality of hot runners A plurality of resin passages that communicate with each other and whose lower ends communicate with the cavities through the gates are provided in the resin passages. Injection mold characterized in that it is composed of a valve body formed by providing a valve pin for opening and closing the gate insert, respectively.   One heat-insulating ring is attached to the upper end portion of the valve body formed by arranging the resin passages into which the valve pins are inserted side by side, and a heat band is attached to the outer peripheral surface of the valve body. The injection mold according to claim 1.   The valve body is divided into a plurality of parts, and each divided valve body is provided with a single resin passage into which each valve pin is inserted. A heat band is attached to the outer peripheral surface of each divided valve body, and these divided valve bodies The injection mold according to claim 1 or 2, characterized in that the heat insulating rings are bundled in a uniform manner and one heat insulating ring is attached to the upper end portion so as to surround these divided valve bodies.   The common passage is provided in the lower end gate of a plurality of resin passages arranged side by side through an extension passage having a short length, and the common passage communicates with the cavity. Item 4. A mold for injection molding according to Item 3.   The distance between the valve pins in the adjacent resin passages is made smaller than the diameter of the cylinder for operating these valve pins installed on the hot runner block, while the outer end of the support piece is attached to the rod of the adjacent valve pin operating cylinder. 3. The fixing device according to claim 1, wherein the inner end portions of the support pieces are opposed to each other in close proximity, and the head portions of the valve pins are connected to and supported by the inner end portions, respectively. The mold for injection molding as described.   A fixed base provided with a plurality of hot runner inlets is arranged on the upper surface of the hot runner block, and guide members are arranged side by side at a fixed interval on the fixed base, and a nozzle is interposed between the guide members. The touch block is disposed so as to be reciprocally movable in the length direction of the guide member. Further, a straight flange portion having a certain width is provided on the upper portion of the opposite end portion of the guide member, and the lower surface of the flange portion is provided. The upper surfaces of the engaging flange portions projecting from the lower portions on both sides of the nozzle touch block are slidably engaged, and the lower surface of these straight flange portions and the upper surface of the engaging flange portion are lengthwise. When the introduction port is located directly below the nozzle of the molding unit due to the movement of the nozzle touch block, a convex portion is provided on the lower surface of the straight flange portion of the guide member. Nozzle The injection molding metal according to claim 1, wherein the nozzle touch block is configured to be pressed onto the fixed base by running a convex portion provided on the upper surface of the engaging flange portion of the H block. Type.   A position detection sensor is provided for detecting the position of the introduction port when the nozzle inlet block is located immediately below the nozzle of the molding unit due to the movement of the nozzle touch block, and stopping the movement of the nozzle touch block. The injection mold according to claim 1 or 6.

Images