JP2017170738A - Injection molding device, and control method for resin flow of injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that since a conventional injection molding device is complicate in structure for controlling the flow of a molten resin, smooth operation or the like is damaged by influence of heat or pressure of the molten resin.SOLUTION: There is provided an injection molding device 1 comprising: an injection valve 4 for injecting a molten resin into a cavity 3 of a molding die 2; a valve pin 5 disposed coaxially in the injection valve 4 so as to be capable of advancing/retreating, and also opening or closing a valve gate 4A by the apex thereof; a pin drive part 6 advancing/retreating the valve pin 5 in an axial direction while retaining the pin in a penetration state; and an opening adjustment unit 7 disposed on a fixed die plate 11 facing the rear end of the valve pin 5 and adjusting the retreat limit of the valve pin 5. A structure for controlling the flow of the molten resin is simplified, and the smooth operation over a long period and leakage prevention of the molten resin are achieved by substantially reducing the influence of heat or pressure of the molten resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an injection molding apparatus used for manufacturing a resin molded product, and a resin flow rate control method for the injection molding apparatus.

  As a conventional injection molding apparatus, for example, there is one described in Patent Document 1. The injection molding apparatus described in Patent Literature 1 includes a nozzle for injecting a molten resin into a cavity of a molding die, and a tubular pressure-moving control plunger that is fitted to the nozzle is movably inserted into the nozzle. The flow control plunger is provided. The injection molding apparatus includes a rotating member that is screwed to the end of the flow control plunger, and a gear mechanism that rotates the rotating member.

  The above injection molding apparatus opens and closes the nozzle by driving the pressure holding control plunger back and forth in the axial direction. Further, the injection molding apparatus moves the flow control plunger screwed to the rotating member in the axial direction by rotating the rotating member with a gear mechanism, thereby changing the flow path area in the nozzle. Thus, the flow rate of the molten resin is controlled.

Japanese Patent Publication No. 6-15188

  However, the conventional injection molding apparatus as described above has a structure including a double-structured plunger, a rotating member and a gear mechanism for driving the flow rate control plunger, and thus has a complicated structure. Moreover, since each structural member including the plunger through which the high-temperature molten resin flows is mechanically engaged with the above injection molding apparatus, it is easily affected by the heat and pressure of the molten resin. For this reason, in the conventional injection molding apparatus, there is a possibility that the constituent members may be deformed and the smooth operation may be impaired, or the molten resin may leak from between the constituent members, and it is a problem to solve these problems Met.

  The present invention has been made paying attention to the above-mentioned conventional problems. In addition to simplifying the structure for controlling the flow rate of the molten resin, smooth operation over a long period of time and prevention of leakage of the molten resin can be achieved. It is an object of the present invention to provide an injection molding apparatus capable of realizing the above and a resin flow rate control method for the injection molding apparatus.

  An injection molding apparatus according to the present invention includes an injection valve for injecting a molten resin into a cavity of a molding die, a valve pin that is arranged in the injection valve so as to be movable back and forth in a coaxial state, and that opens and closes a valve gate at the tip thereof, and a valve pin And a pin drive unit that holds the pin in a penetrating state and drives to advance and retreat in the axial direction. The injection molding apparatus includes an opening degree adjusting device that is disposed at a fixed portion opposite to the rear end of the valve pin and adjusts the retreat limit of the valve pin.

  A resin flow rate control method for an injection molding apparatus according to the present invention includes an injection valve for injecting molten resin into a cavity of a molding die, and a valve gate that opens and closes at the tip of the injection valve arranged coaxially in the injection valve. This is a method of controlling the flow rate of molten resin injected into a cavity in an injection molding apparatus comprising a valve pin that performs the above operation and a pin drive unit that holds the valve pin in a penetrating state and drives it to advance and retreat in the axial direction. This resin flow rate control method uses a position adjustment member that abuts the rear end of the valve pin to regulate its retreat limit, and the position adjustment member limits the retreat limit of the valve pin according to the amount of molten resin required on the cavity side. This is characterized in that the flow rate of the molten resin is controlled by setting the distance between the valve gate and the tip of the valve pin.

  The injection molding apparatus according to the present invention adjusts the interval between the valve gate and the tip of the valve pin at the time of injection, that is, the opening degree of the valve gate by adjusting the receding limit of the valve pin by the opening degree adjusting device. The flow rate of the molten resin is controlled. At this time, since the injection molding apparatus employs a valve pin that has penetrated the pin driving portion and a receding limit adjustment device that is disposed at a fixed portion opposite to the rear end of the valve pin, high-temperature molten resin circulates. An opening degree adjusting device is disposed at a position away from the injection valve, and adjustment of the backward limit of the valve pin is performed by this opening degree adjusting device.

  As a result, the injection molding apparatus can simplify the structure for controlling the flow rate of the molten resin, and can greatly reduce the influence of the heat and pressure of the molten resin. Leakage prevention can be realized.

  Further, according to the resin flow rate control method of the injection molding apparatus according to the present invention, the opening degree of the valve gate is adjusted by using a device having a simple structure in accordance with the amount of molten resin required on the cavity side. It is possible to reliably control the flow rate of the molten resin in the valve.

The horizontal sectional view (A) explaining 1st Embodiment of the injection molding apparatus concerning this invention, the horizontal sectional view (B) of the principal part which shows the state at the time of valve gate closing in an injection valve, and the state at the time of valve gate opening | release It is a horizontal sectional view (C) of the important part showing. The perspective view (A) which shows the position adjustment member of the opening degree adjustment apparatus in 1st Embodiment, the front view (B) which shows the front end surface of a position adjustment member, respectively horizontal sectional drawing (C) which shows the state from which the retreat limit of a valve pin differs ) (D). The perspective view (A) which shows the position adjustment member of the opening degree adjustment apparatus in 2nd Embodiment, the front view (B) which shows the front end surface of a position adjustment member, and the horizontal sectional view (C) which shows the state at the time of valve gate opening It is. The perspective view (A) which shows the position adjustment member of the opening degree adjustment apparatus in 3rd Embodiment, the front view (B) which shows the front end surface of a position adjustment member, the horizontal sectional view (C) which shows the state at the time of valve gate opening, It is a perspective view (D) which shows the position adjustment member provided with the other positioning mechanism. It is a horizontal sectional view explaining a 4th embodiment of an injection molding device concerning the present invention.

<First Embodiment>
1 and 2 are views for explaining a first embodiment of an injection molding apparatus according to the present invention.
An injection molding apparatus 1 shown in FIG. 1 (A) has an injection valve 4 for injecting molten resin into a cavity 3 of a mold 2, and is arranged in the injection valve 4 so as to be able to advance and retreat in a coaxial state. A valve pin 5 that opens and closes the gate 4A, and a pin drive unit 6 that holds the valve pin 5 in a penetrating state and drives it to advance and retreat in its axial direction.

  Further, the injection molding device 1 is provided with an opening degree adjusting device 7 that is disposed at a fixed portion facing the rear end of the valve pin 5 and adjusts the backward limit of the valve pin 5. In FIG. 1, illustration of a molten resin injection machine is omitted, and the molten resin is pressurized and supplied through a nozzle N of the injection machine as indicated by an arrow.

  More specifically, the injection molding apparatus 1 has a fixed die plate 11 shown on the right side in the figure and a fixed die 13 that constitutes the molding die 2 via a die holder 12 and is movable on the left side in the figure. A movable mold 16 constituting the mold 2 is disposed on the die plate 14 via a die holder 15. A cavity 3 that is a molding space is formed between the fixed mold 13 and the movable mold 16. The nozzle N of the injection machine is provided on the fixed die plate 11.

  A sprue 17 that communicates with the nozzle N and a hot runner block 18 that forms a branch path that communicates with the sprue 17 are disposed between the fixed die plate 11 and the fixed mold 13. A plurality of (three in the illustrated example) injection valves 4 arranged in parallel are incorporated in the fixed mold 13, and a branch path of the hot runner block 18 communicates with each injection valve 4.

  The configuration of the movable die 16 is not particularly limited. In the illustrated example, the movable die 16 includes a plurality of divided dies 16A to 16D, and an ejector plate 19 and an ejector pin 20 between the movable die plate 14 and the movable die 16. Well-known devices such as the return pin 21 and the guide pin 22 are arranged. The movable die 16 is driven forward and backward toward the fixed die 13 by a driving device (not shown), and after moving forward and performing injection molding, each of the divided dies 16A to 16D and the ejector pins 20 are operated in predetermined directions while moving backward. And release the molded product.

  As shown in FIGS. 1B and 1C, the injection valve 4 is a cylindrical member (valve body) having a valve gate 4 </ b> A at the tip, and the valve gate 4 </ b> A opens on the inner wall surface of the cavity 3. In addition, the base end communicates with the branch path of the hot runner block 18. The injection valve 4 includes a heater 23 between the outer peripheral portion and the fixed mold 13 for maintaining the temperature of the molten resin.

  The valve pin 5 is arranged in the injection valve 4 so as to be able to advance and retreat in a coaxial state, and is held in a state of penetrating the hot runner block 18 and the pin driving unit 6. As a matter of course, the valve pin 5 penetrates the hot runner block 18 and the pin drive unit 6 so as to be able to advance and retreat in a state in which sealing performance is secured by a seal member or the like.

  The pin drive unit 6 in the illustrated example is, for example, a hydraulic cylinder, and includes a piston 24 fixed to the valve pin 5, two pressure chambers formed on both sides of the piston 24, and a hydraulic circuit for supplying and discharging hydraulic oil ( (Not shown). The pin driving unit 6 reciprocates the piston 24 while changing the volumes of both pressure chambers in inverse proportion to the supply and discharge of hydraulic oil, and drives the valve pin 5 to advance and retreat in the axial direction together with the piston 24.

  As shown in FIG. 1B, the injection valve 4 closes the valve gate 4 </ b> A with the valve pin 5 moved to the forward limit by the pin drive unit 6, and retracts the valve pin 6 by the pin drive unit 6. The valve gate 4A is opened. In addition, as shown in FIG. 1C, the injection valve 4 abuts the rear end of the valve pin 5 on the fixed die plate 11 and sets the position as the backward limit of the valve pin 5.

  Therefore, the injection molding apparatus 1 adjusts the retreat limit of the valve pin 5 on the fixed die plate 11 as a fixed part opposite to the rear end of the valve pin 5 as shown by a one-dot chain line in FIG. An opening adjustment device 7 is arranged. The opening adjusting device 7 adjusts the opening of the valve gate 4 </ b> A by adjusting the backward limit of the valve pin 5. In the illustrated example, the opening degree adjusting device 7 is arranged for the injection valves 4 on both sides of the three injection valves 4 arranged in parallel.

  As shown in FIG. 2, the opening adjustment device 7 includes a position adjustment member 25 that abuts the rear end of the valve pin 5 and a positioning mechanism 26 of the position adjustment member 25. The position adjusting member 25 has a restricting portion 27 that changes the backward limit of the valve pin 5 according to the contact position of the rear end of the valve pin 5. On the other hand, the positioning mechanism 26 is a mechanism that restrains the position adjusting member 25 in a state where the rear end of the valve pin 5 and the contact position selected by the restricting portion 27 are matched.

  As shown in FIGS. 2A and 2B, the position adjusting member 25 of this embodiment is a long member having a restricting portion 27 at the tip, and the restricting portion 27 has a height toward the tip. A plurality of receiving portions 27 </ b> A to 27 </ b> C that differ in stages are provided, and the receiving portions 27 </ b> A to 27 </ b> C are used as contact positions of the rear end of the valve pin 5.

  More specifically, the position adjusting member 25 is a long member having a rectangular cross section, and has a step-like restricting portion 27 whose height decreases stepwise toward the distal end at the distal end, An operation portion 25A having a circular cross section is provided on the side. The restricting portion 27 in the illustrated example has two steps, and the upper, middle, and lower steps, which are main body portions, are the receiving portions 27 </ b> A to 27 </ b> C, respectively, and these are the contact positions of the rear end of the valve pin 5.

  The position adjusting member 25 is disposed on the fixed die plate (fixed portion) 11 in a horizontal state in which the longitudinal direction is the horizontal direction and the receiving portions 27A to 27C are on the valve pin 5 side. The position adjusting member 25 is held by a retainer 28 provided on the fixed die plate 11 so as to be movable in the longitudinal direction, as indicated by phantom lines in the figure.

  On the other hand, the positioning mechanism 26 is a mechanism that restrains the movement in the longitudinal direction on the proximal end side of the position adjusting member 25. The positioning mechanism 26 of this embodiment includes three bolt insertion holes 29A to 29C provided in the operation portion 25A of the position adjustment member 25, bolts 30 that are selectively inserted into the bolt insertion holes 29A to 29C, and a fixed die plate. 11 and a screw hole 31 formed in the head 11. The three bolt insertion holes 29A to 29C are arranged at predetermined intervals in the axial direction of the operation portion 25A. At this time, the bolt insertion holes 29A to 29C are arranged at the same pitch P as the pitch P of the receiving portions 27A to 27C of the position adjusting member 25. is there.

  Thereby, as shown in FIG. 2 (C), the opening degree adjusting device 7 is located at the most proximal side of the operating portion 25A at the position where the rear end of the valve pin 5 contacts the upper receiving portion 27A of the position adjusting member 25. The screw insertion hole 29A and the screw hole 31 coincide with each other. Then, the opening adjusting device 7 restrains the movement of the position adjusting member 25 in the longitudinal direction by means of the bolt 30 provided in the screw insertion hole 29 </ b> A and the screw hole 31, that is, the positioning mechanism 26.

  Further, as shown in FIG. 2D, the opening degree adjusting mechanism 7 moves the position adjusting member 25 in the longitudinal direction so that the other screw insertion holes 29B (or 29C) and the screw holes 31 coincide with each other. For example, the rear end of the valve pin 5 contacts the other receiving portion 27 </ b> B (or 29 </ b> C) of the position adjusting member 25.

  In this way, the opening adjustment mechanism 7 adjusts (changes) the backward limit of the valve pin 5 in FIGS. 2 (C) and 2 (D), so that the distance between the valve gate 4A and the tip of the valve pin 5, that is, the valve gate. The opening degree of 4A will be adjusted (changed) step by step.

  The injection molding apparatus 1 having the above configuration can apply the following resin flow rate control method. That is, the resin flow rate control method of the injection molding apparatus 1 sets the retreat limit of the valve pin 5 by the position adjusting member 25 according to the amount of molten resin required on the cavity 3 side, and thereby the valve gate 4A and the valve pin 5 The distance from the tip is set to control the flow rate of the molten resin.

  The injection molding apparatus 1 controls the flow rate of the molten resin in each injection valve 4 so that the molten resin can be optimally filled in a short time according to the shape of the cavity 3 (the shape of the molded product), for example. The injection molding apparatus 1 of this embodiment controls the flow rate of the molten resin in the injection valves 4 on both sides of the three injection valves 4 arranged in parallel.

  That is, in the opening degree adjusting device 7, the position adjusting member 25 is moved in the longitudinal direction so that the valve gate 4A has a desired opening degree, and the contact position of the rear end of the valve pin 5 is selected from the receiving portions 27A to 27C. Then, the position adjusting member 25 is restrained by the positioning mechanism 26. For this operation, in the positioning mechanism 26, any one of the bolt insertion holes 29A to 29C may be selected for the screw hole 31, and as a result, any of the receiving portions 27A to 27C can be selected. Further, since the position adjustment member 25 is a long member and the operation portion 25A extends outward from between the fixed die plate 11 and the fixed mold 13, the opening adjustment device 7 is easy to adjust. .

  Thereafter, the injection molding apparatus 1 pressurizes and supplies the molten resin from an injection machine (not shown) to distribute the molten resin to the nozzle N, the sprue 17 and the hot runner block 18, and enters the cavity 3 from each injection valve 4. Inject molten resin. At this time, the injection molding apparatus 1 sets the distance between the tip of the valve pin 5 and the valve gate 4A, that is, the opening degree of the valve gate 4A, by setting the retreat limit of the valve pin 5 in advance on the injection valves 4 on both sides. Therefore, the molten resin is injected at a flow rate corresponding to it. Further, after the injection of the molten resin, in each injection valve 4, the valve pin 5 is advanced and the valve gate 4A is closed at the tip thereof.

  The injection molding apparatus 1 having the above-described configuration is, in particular, a receding limit adjusting device disposed at a fixed portion (fixed die plate 11) opposed to the rear end of the valve pin 5 and the valve pin 5 in a state of penetrating the pin driving unit 6. 7 is employed, the opening degree adjusting device 7 is arranged at a position separated from the injection valve 4 through which the high-temperature molten resin flows, and the opening adjustment device 7 adjusts the retreat limit of the valve pin.

  As a result, the injection molding apparatus 1 can simplify the structure for controlling the flow rate of the molten resin, and can greatly reduce the influence of the heat and pressure of the molten resin. Combined with the reduction of the influence of the above, smooth operation over a long period of time and prevention of leakage of the molten resin can be realized. Moreover, the injection molding apparatus 1 does not need to change the structure of the principal part of the injection valve 4, and can easily incorporate the opening degree adjusting apparatus 7 into existing equipment.

  Furthermore, according to the resin flow rate control method of the injection molding apparatus 1 described above, the opening of the valve gate 4A is adjusted using an apparatus having a simple structure according to the amount of molten resin required on the cavity 3 side, The flow rate control of the molten resin in the injection valve 4 can be reliably performed.

  Further, the injection molding apparatus 1 employs an opening degree adjusting device 7 that includes a position adjusting member 25 that contacts the rear end of the valve pin 5 and a positioning mechanism 26 of the position adjusting member 25. In the opening adjustment device 7, the position adjustment member 25 has a restricting portion 27 that changes the retreat limit of the valve pin 5 according to the contact position of the rear end of the valve pin 5, and the positioning mechanism 26 includes the valve pin 5. In this state, the position adjusting member 25 is restrained in a state where the rear end and the contact position selected by the restricting portion 27 are matched.

  As a result, the injection molding apparatus 1 can mechanically adjust the opening of the valve gate 4A without using an electronic control means, realizing further simplification of the structure of the opening adjusting apparatus 7, and durability. Improvement of productivity, reduction of production costs, simplification of maintenance management, and the like.

  Further, in the injection molding apparatus 1, the position adjusting member 25 is a long member having a restricting portion 27 at the tip, and the restricting portion 27 has a plurality of receiving portions 27A to 27H whose heights are gradually different toward the tip. 27C and the receiving portions 27A to 27C are the contact positions of the rear end of the valve pin 5, and the positioning mechanism 26 is a mechanism that restrains the movement in the longitudinal direction on the base end side of the position adjusting member 25. Yes. As a result, the injection molding apparatus 1 has a simpler and cheaper structure of the opening degree adjusting mechanism 7, and the adjustment work can be performed very easily and reliably.

  In addition, since the injection molding apparatus 1 of the said embodiment can determine the retreat limit of the valve pin 5 also by the fixed die plate 11, it adds one bolt insertion hole of the positioning mechanism 26 in the opening degree adjustment apparatus 7, The position adjusting member 25 may be restrained at a position where the rear end of the valve pin 5 contacts the fixed die plate 11, that is, a position where the position adjusting member 25 is detached from the rear end. Further, the positioning mechanism 26 may be a combination of a pin and a fitting hole instead of the combination of the bolt 30 and the screw hole 31.

Second Embodiment
The opening adjusting device 7 of the injection molding apparatus shown in FIG. 3 includes a position adjusting member 35 that abuts the rear end of the valve pin 5 and a positioning mechanism 36 for the position adjusting member 35. The position adjusting member 35 has a restricting portion 37 that changes the retreat limit of the valve pin 5 according to the contact position of the rear end of the valve pin 5. On the other hand, the positioning mechanism 36 is a mechanism that restrains the position adjusting member 35 in a state where the rear end of the valve pin 5 and the contact position selected by the restricting portion 37 are matched.

  As shown in FIG. 3A, the position adjusting member 35 of this embodiment is a long member having a restricting portion 37 at the tip, and the restricting portion 37 has a plurality of groove-shaped receiving portions having different depths. 35A to 35D are arranged in the direction around the axis, and the receiving portions 35A to 35D are set as contact positions of the rear end of the valve pin 5.

  More specifically, the position adjusting member 35 is a long member having a circular cross section, and, as shown in FIG. 3B, four receiving portions 35A to 35D having different depths D1 to D4 are provided at the tip. It has the regulation part 37 formed at intervals of 90 degrees. The bottom surfaces of the groove-shaped receiving portions 35 </ b> A to 35 </ b> D are contact positions of the rear end of the valve pin 5.

  The position adjusting member 35 is disposed on the fixed die plate (fixed part) 11 with the longitudinal direction set in the horizontal direction. Further, the position adjustment member 35 is rotatably held by a retainer 38 provided on the fixed die plate 11 as indicated by an imaginary line in the drawing.

  On the other hand, the positioning mechanism 36 is a mechanism that restrains the rotation around the axis on the proximal end side of the position adjusting member 35. The positioning mechanism 36 of this embodiment is a motor 39 that outputs a rotational motion, and connects the output shaft 39A to the proximal end portion of the position adjusting member 35. Therefore, the positioning mechanism 36 of this embodiment also serves as a rotational drive source for the position adjusting member 35.

  As shown in FIG. 3C, the opening degree adjusting device 7 rotates the position adjusting member 35 by a motor 39 so that the rear end of the valve pin 5 and the selected receiving portions 37A to 37D coincide with each other. The rotation of the position adjustment member 35 is restrained by stopping 39. Therefore, the motor 39 that is the positioning mechanism 36 is more preferably a motor having a rotation detection function and a brake.

  In this way, the opening degree adjusting device 7 selects the receiving portions 37A to 37D having different depths D1 to D4 and adjusts (changes) the retreat limit of the valve pin 5 to thereby adjust the valve gate 4A and the valve pin 5. Is adjusted (changed) stepwise, that is, the opening of the valve gate 4A.

  Since the injection molding apparatus having the above-described configuration can simplify the structure for controlling the flow rate of the molten resin as in the previous embodiment, it can greatly reduce the influence of the heat and pressure of the molten resin. Combined with the simplification of the structure and the reduction of the influence of heat and pressure, it is possible to realize smooth operation over a long period of time and prevention of leakage of the molten resin.

  Further, the injection molding apparatus employs an opening degree adjusting device 7 including a position adjusting member 35 and a positioning mechanism 36, and the position adjusting member 35 moves the receiving portions 37A to 37D having different depths D1 to D4 around the axis. The positioning mechanism 36 is a rotational drive source for the position adjusting member 35 and a mechanism for restraining the rotation thereof.

  In the above injection molding apparatus, the opening adjustment device 7 has a simpler and cheaper structure, and the positioning mechanism 36 includes the motor 39. Therefore, the valve gate 4A by adjusting the retreat limit of the valve pin 5 is provided. The opening degree adjustment, that is, the flow rate control of the molten resin in the injection valve 4 can be performed by electronic control, and automation can be achieved.

<Third Embodiment>
The opening adjusting device 7 of the injection molding apparatus shown in FIG. 4 includes a position adjusting member 45 that abuts the rear end of the valve pin 5 and a positioning mechanism 36 for the position adjusting member 45. The position adjusting member 35 has a restricting portion 37 that changes the retreat limit of the valve pin 5 according to the contact position of the rear end of the valve pin 5. On the other hand, the positioning mechanism 36 is a mechanism that restrains the position adjusting member 35 in a state where the rear end of the valve pin 5 and the contact position selected by the restricting portion 37 are matched.

  As shown in FIGS. 4A and 4B, the position adjusting member 45 of this embodiment is a long member having a restricting portion 47 at the tip, and the restricting portion 47 has a height toward the tip. The receiving portion 47 </ b> A has continuously different slopes, and the receiving portion 47 </ b> A is used as a contact position of the rear end of the valve pin 5. The restricting portion 46 in the illustrated example has a sloped receiving portion 47A whose height gradually decreases toward the tip.

  The position adjusting member 45 is disposed on the fixed die plate (fixed portion) 11 in a horizontal state in which the longitudinal direction is the horizontal direction and the receiving portion 47A is the valve pin 5 side. The position adjusting member 45 is held by a retainer 48 provided on the fixed die plate 11 so as to be movable in the longitudinal direction, as indicated by phantom lines in the drawing.

  On the other hand, the positioning mechanism 46 is a mechanism that restrains the movement in the axial direction on the proximal end side of the position adjusting member 45. The positioning mechanism 46 of this embodiment is a motor 49 that outputs a linear motion, and its output shaft 49 </ b> A is connected to the proximal end portion of the position adjusting member 45. Therefore, the positioning mechanism 46 of this embodiment also serves as an advance / retreat drive source for the position adjusting member 45.

  As shown in FIG. 4C, the opening adjusting device 7 moves the position adjusting member 35 in the longitudinal direction by the motor 49 so that the contact position of the rear end of the valve pin 5 changes within the range of the receiving portion 47A. The movement of the position adjusting member 45 is constrained by stopping the motor 49. Therefore, the motor 49 that is the positioning mechanism 46 is more preferably a motor having an advancing / retreating position detecting function and a brake.

  In this way, the opening adjustment device 7 selects the contact position in the inclined receiving portion 47A and adjusts (changes) the retreat limit of the valve pin 5 to thereby change the valve gate 4A and the valve pin 5 from each other. The distance from the tip, that is, the opening of the valve gate 4A can be continuously adjusted (changed).

  Since the injection molding apparatus having the above-described configuration can simplify the structure for controlling the flow rate of the molten resin as in the previous embodiment, it can greatly reduce the influence of the heat and pressure of the molten resin. Combined with the simplification of the structure and the reduction of the influence of heat and pressure, it is possible to realize smooth operation over a long period of time and prevention of leakage of the molten resin.

  Further, the injection molding apparatus employs an opening degree adjusting device 7 having a position adjusting member 45 and a positioning mechanism 46, and the position adjusting member 45 has a regulating portion 47 having a sloped receiving portion 37A. The positioning mechanism 46 is a mechanism for advancing and retracting the position adjusting member 35 and restraining its movement.

  In the above injection molding apparatus, the structure of the opening adjustment device 7 becomes much simpler and less expensive, and the positioning mechanism 46 includes the motor 49. Therefore, the valve gate 4A by adjusting the retreat limit of the valve pin 5 is provided. The opening degree adjustment, that is, the flow rate control of the molten resin in the injection valve 4 can be performed by electronic control, and automation can be achieved.

   Further, when the position adjusting member 45 having the inclined receiving portion 47A is adopted as the restricting portion 47 in the opening degree adjusting device 7, the injection molding device 7 replaces the motor 49 with the positioning mechanism 46 shown in FIG. A combination of the bolt 30 and the long hole-shaped bolt insertion hole 32 shown in (D) can be employed.

  In this case, the position adjustment member 45 has an operation portion 45A instead of the output shaft of the motor on the base end side. The bolt 30 is screwed into a screw hole (see FIG. 2) provided in the fixed die plate 11. The bolt insertion hole 32 is a long hole formed along the axial direction of the operation portion 45A and having a length corresponding to the slope length of the receiving portion 47A. Even if such a position adjusting member 45 is used, the same effects as those of the previous embodiment can be obtained. In particular, the electronic control means is not required, and the opening degree of the valve gate 4A can be adjusted and melted by a simple operation. Resin flow rate can be controlled.

<Fourth embodiment>
An injection molding apparatus 51 shown in FIG. 5 includes first and second molding dies 52 and 53. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  The first and second molding dies 52 and 53 include respective fixed dies 52A and 53A and movable dies 52B and 53B, and have cavities 52C and 53C, respectively. In the illustrated injection molding apparatus 50, the first mold 52 is relatively large. Thereby, in the injection molding apparatus 51, two injection valves 4 and 4 out of the three arranged in parallel are arranged in the fixed mold 52A of the first molding die 52, and the remaining one injection valve 4 is arranged. However, it is arranged on the fixed mold 53 </ b> A of the second mold 53.

  The injection molding apparatus 51 can apply the resin flow rate control method described in the first embodiment, and is particularly suitable for the following resin flow rate control method. According to the resin flow rate control method, in a device equipped with a plurality of injection valves 4, each valve pin 5 is retracted by a position adjusting member for each injection valve 4 according to the amount of molten resin required on the cavities 52 </ b> C and 53 </ b> C side. This is a method of setting limits individually.

  That is, in the injection molding apparatus 51, the sizes of the cavities 52C and 53C in the first and second molding dies 52 and 53 are different, and naturally the filling amount of the molten resin into the cavity 53C having a small volume is small. Therefore, the injection molding device 51 controls the flow rate of the molten resin in each injection valve 4 by adjusting the opening degree of the valve gate 4A of the injection valve 4 on both sides by the respective opening degree adjustment devices 7.

  Thereby, the injection molding apparatus 51 can inject efficiently the molten resin pressurized and supplied from the injection machine outside a figure with respect to cavity 52C, 53C from which a magnitude | size differs. Here, as explained in the first embodiment, the injection molding apparatus according to the present invention is adapted to the form of the cavity 3 and the positions of the plurality of valve gates 4A even when the molten resin is injected into one cavity 3. Therefore, it is very effective to control the flow rate of each injection valve 4. On the other hand, when the molten resin is injected into the plurality of cavities 52C and 53C having different sizes as in this embodiment, the difference in the amount of molten resin required on the cavity side is more obvious. The effect | action and effect in controlling the flow volume of molten resin can be exhibited further.

  The configuration of the injection molding apparatus and the resin flow rate control method of the injection molding apparatus according to the present invention is not limited to the above embodiments, and the configuration details are changed without departing from the gist of the present invention. It is possible to combine the configurations of the above embodiments. In particular, in each embodiment, the opening adjustment device is configured to be arranged on the side portion (upper and lower portions in FIG. 1) of the injection molding device, but is not limited to this, and the position and number of injection valves are not limited thereto. It is possible to arrange according to the above.

DESCRIPTION OF SYMBOLS 1,51 Injection molding apparatus 2,52,53 Mold 3,52C, 53C Cavity 4 Injection valve 4A Valve gate 5 Valve pin 6 Pin drive part 7 Opening adjustment apparatus 11 Fixed die plate (fixed part)
25, 35, 45 Position adjusting member 26, 36, 46 Positioning mechanism 27, 37, 47 Restricting portion 27A to 27C Receiving portion (contact position)
37A to 37D Receiving part (contact position)
47A Receiving part (contact position)

Claims (7)

An injection valve for injecting molten resin into the cavity of the mold,
A valve pin which is arranged in the injection valve so as to be movable back and forth in a coaxial state and which opens and closes the valve gate at its tip;
A pin drive unit that holds the valve pin in a penetrating state and drives it to advance and retreat in the axial direction;
An injection molding apparatus comprising: an opening degree adjusting device that is disposed at a fixed portion opposite to a rear end of the valve pin and adjusts a backward limit of the valve pin. The opening adjustment device includes a position adjustment member that abuts the rear end of the valve pin, and a positioning mechanism for the position adjustment member,
The position adjusting member has a restricting portion that changes a retreat limit of the valve pin according to a contact position of a rear end of the valve pin;
An injection molding apparatus, wherein the positioning mechanism is a mechanism for restraining the position adjusting member in a state where the rear end of the valve pin and the contact position selected by the restricting portion are matched. The position adjusting member is a long member having a restricting portion at the tip, and the restricting portion has a plurality of receiving portions whose heights are stepwise toward the tip, and each receiving portion is abutted against the rear end of the valve pin. It is a close position,
The injection molding apparatus according to claim 2, wherein the positioning mechanism is a mechanism that restrains movement in the longitudinal direction on the base end side of the position adjusting member. The position adjusting member is a long member having a restricting portion at the tip, and the restricting portion has a plurality of groove-like receiving portions with different depths arranged in the direction around the axis, and each receiving portion is disposed behind the valve pin. It is the contact position of the end,
The injection molding apparatus according to claim 2, wherein the positioning mechanism is a mechanism that restrains the rotation in the direction around the axis on the base end side of the position adjusting member. The position adjusting member is a long member having a restricting portion at the tip, and the restricting portion has a slope-shaped receiving portion having different heights continuously toward the tip, and the receiving portion is abutted against the rear end of the valve pin. It is a close position,
The injection molding apparatus according to claim 2, wherein the positioning mechanism is a mechanism that restrains movement in the longitudinal direction on the base end side of the position adjusting member. An injection valve for injecting the molten resin into the cavity of the mold, a valve pin that is arranged in the injection valve so as to be able to advance and retreat in the coaxial state, and opens and closes the valve gate at its tip, and an axis line that holds the valve pin in a penetrating state In an injection molding apparatus having a pin drive unit that moves forward and backward in the direction, when controlling the flow rate of the molten resin injected into the cavity,
Using a position adjustment member that abuts the rear end of the valve pin and changes its backward limit,
According to the amount of molten resin required on the cavity side, the retraction limit of the valve pin is set by the position adjustment member, thereby setting the distance between the valve gate and the tip of the valve pin to control the flow rate of the molten resin A resin flow rate control method for an injection molding apparatus. The injection molding device has a plurality of injection valves,
7. The resin flow rate of the injection molding apparatus according to claim 6, wherein the retreat limit of each valve pin is individually set by a position adjusting member for each injection valve according to the amount of molten resin required on the cavity side. Control method.

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