JP7759649B2 - Injection molding apparatus and injection molding method - Google Patents

Description

The present invention relates to an injection molding apparatus and an injection molding method.

Insert injection molding technology is known for producing connectors used to connect electronic circuits. The connector components are inserted into a mold as insert parts, and then resin is injected into the mold to integrate them. Conventional injection molding methods involve first fixing connector components, such as signal terminals made of expensive, rare metal substrates or plated parts, to a carrier made of an inexpensive material, and then inserting the insert part and the carrier into the mold to produce an injection-molded product (see, for example, Patent Documents 1 and 2). This injection molding method has the advantage of allowing the insert part and carrier to be made of different materials, thereby reducing the cost of connector production.

However, conventional injection molding methods require, in addition to the injection molding machine, a carrier mark position reading device and a fixing device for fixing the insert parts and carrier, as insert parts such as signal terminals, which are becoming smaller and narrower in pitch, are fixed in the designated position on the carrier. Conventional injection molding methods have a complex overall injection molding device configuration and procedures, including mark position reading and fixing the insert parts to the carrier, making it difficult to shorten the elapsed time from adding the insert parts to completing the injection molded product, i.e., the injection molding cycle time.

Furthermore, when attempting to mass-produce connectors using injection molding, it is necessary to place not only the component materials, but also multiple insert components of different sizes and shapes, such as the connector's signal terminals, ground components, and nail components, into the mold at the appropriate time, and repeatedly produce injection-molded products. Conventional injection molding methods have had the problem of being difficult to adapt to this type of mass-production of connectors.

Japanese Patent No. 3338667 JP 2017-193083 A

The present invention aims to provide an injection molding apparatus and method that combines individual insert components, such as connector signal terminals, with hoop-shaped insert components, such as ground components and nail components, within a mold during injection molding, allowing for the repeated production of connectors, which are injection-molded products containing multiple insert components.

To achieve the above objective, the injection molding apparatus of the present invention is an injection molding apparatus that produces a molded product according to the shape of the cavity space by injecting resin into a cavity space formed by opening and closing and clamping an upper mold relative to a lower mold in which individual insert parts and hoop-shaped insert parts arranged on a strip-shaped carrier are placed. The injection molding apparatus includes a lower platen unit equipped with a moving table that mounts and moves the lower mold, an ejector rod that is inserted into a through-hole that penetrates the lower platen unit when the lower mold is positioned opposite the upper mold, a pass line lifter that sets the height and orientation of the strip surface of the strip-shaped carrier and the transport direction of the strip-shaped carrier, and a carrier transport unit that transports the strip-shaped carrier in the extension direction of the strip-shaped carrier by a specified feed amount.

Furthermore, using the above-mentioned injection molding apparatus, the injection molding method of the present invention involves the following steps, in this order: a first step of using a moving table to move the lower mold, on which the individual insert parts are installed, to a position opposite the upper mold; a second step of setting the strip-shaped carrier supported by the pass line lifter to the height at which the hoop-shaped insert parts will be installed in the lower mold and setting the tip of the ejector rod to the height inside the through-hole in the lower platen; a third step of closing and clamping the upper mold to form a cavity space within the mold; a fourth step of injecting resin into the cavity space to produce an injection-molded product; a fifth step of moving the upper mold to open it; a sixth step of pushing the injection-molded product with the tip of the ejector rod and moving the strip-shaped carrier supported by the pass line lifter to the height of the carrier transfer unit approximately synchronized with the extrusion of the injection-molded product; a seventh step of retracting the ejector rod from the through-hole in the moving table; and an eighth step of transferring the strip-shaped carrier using the carrier transfer unit.

With the injection molding device of the present invention, the installation of the insert part, the joining of the insert part by injection molding, and the removal and transportation of the injection molded product are all performed within the injection molding device. This allows for a reduction in the injection molding cycle time.

The injection molding method of the present invention allows for a series of processes using an injection molding device, including the placement of insert parts, joining of the insert parts by injection molding, and removal and transportation of the injection molded product, to be performed repeatedly in a cyclical manner. This makes it possible to mass-produce connectors using injection molding.

1 is a front view showing an example of the configuration of an injection molding apparatus according to an embodiment. 1 is a side view showing an example of the configuration of an injection molding apparatus according to an embodiment. FIG. 2 is a front view showing the injection molding apparatus according to the embodiment in a state during injection molding. FIG. 1 is a flow diagram illustrating an example of an injection molding method according to an embodiment. 1A is a cross-sectional view showing an example of the configuration of an injection molding apparatus according to a first modified example, in which (a) is a cross-sectional view showing a state in which upper and lower molds face each other, (b) is a cross-sectional view showing a state in which the upper and lower molds do not face each other, and (c) is a plan view. 10 shows an example of the configuration of an injection molding device according to a second modified example.

(injection molding equipment)
The configuration of an injection molding apparatus 1 according to an embodiment will be described with reference to Figures 1 and 2. The injection molding apparatus 1 shown in Figure 1 is composed of an injection molding unit 2 and a control unit 810 that controls the motors and other components of the injection molding unit 2. Figure 1 shows a front view of the injection molding unit 2 according to an embodiment, and Figure 2 shows a side view of the injection molding unit 2 according to an embodiment. Identical parts of the apparatus are designated by the same reference numerals.

In the coordinate system shown in Figures 1 and 2, the X and Y directions represent the horizontal direction, and the Z direction represents the vertical direction. The +X direction is called the forward direction, and the -X direction is called the backward direction. The +Y direction is called the rightward direction, and the -Y direction is called the leftward direction. The +Z direction is called the upward direction, and the -Z direction is called the downward direction. In other words, Figure 1 is a front view of the injection molding unit 2 as seen from the front, and Figure 2 is a side view of the injection molding unit 2 as seen from the right.

Furthermore, the portion of the injection molded part 2 shown in Figure 1 (the portion with fine hatching) represents a cross section cut along the YZ plane, which includes a Z-axis passing through approximately the center of the upper and lower molds when the upper and lower molds are facing each other. The portion of the injection molded part 2 shown in Figure 2 (the portion with fine hatching) represents a cross section cut along the XZ plane, which includes a Z-axis passing through approximately the center of the molds.

The configuration of the injection molding apparatus 1 will be explained below mainly using Figure 1, but Figure 2 will also be referenced as appropriate.

The hoop-shaped insert component 5 shown at the right end of the injection molded section 2 in Figure 1 is a connector component prepared in advance by performing press processing or the like on the strip-shaped carrier 4, which is an inexpensive metal strip. The hoop-shaped insert component 5 is, for example, a ground component for high-speed transmission noise reduction or a nail component for removal strength. The hoop-shaped insert components 5 are arranged at predetermined intervals in the extension direction of the strip-shaped carrier 4, which has a predetermined width. Furthermore, mark structures such as pilot holes, which serve as a reference when transporting the strip-shaped carrier 4, are provided at predetermined intervals in the extension direction of the strip-shaped carrier 4. The individual insert component 6 shown inside the mold near the center of Figure 1 is, for example, a connector component such as a signal terminal made of an expensive rare metal base material or a rare metal-plated member.

Figure 1 shows the mold installed in the injection molding unit 2 in an open state. The strip-shaped carrier 4 is fed into the injection molding unit 2 with the stretch direction of the strip material oriented in the Y direction, the width direction oriented in the X direction, and the strip surface formed by the stretch direction and width direction in a horizontal plane. Hoop-shaped insert parts 5 are arranged at a predetermined interval on the strip-shaped carrier 4 and fed into the device from the right side of the injection molding unit 2. Individual insert parts 6 are installed at predetermined positions in the mold. The injection molding device 1 combines the hoop-shaped insert parts 5 and the individual insert parts 6 during injection molding to produce an injection-molded product 7. The injection-molded products 7, arranged at a predetermined interval on the strip-shaped carrier 4, are fed out of the injection molding unit 2 to the left in the figure.

Before going into detailed description of each part of the injection molding unit 2, an overview of the mold used in the injection molding unit 2 will be provided. As shown in Figure 1, the mold consists of a lower mold 12 and an upper mold 22. The outer shapes of the lower mold 12 and upper mold 22 are both approximately rectangular parallelepiped. A space 14 provided in the lower mold 12 forms a cavity space that determines the shape of the injection-molded product 7 when the lower mold 12 and upper mold 22 are clamped together. An individual insert part 6 is installed at a predetermined position within the space 14. An ejector 16 provided in the lower mold 12 is a device for removing the injection-molded product 7 from the lower mold 12. A flow path 24 provided in the upper mold 22 is a flow path for pouring molten resin into the cavity space within the mold during injection molding.

The injection molding unit 2 is composed of a mold clamping mechanism 10, a mold clamping drive unit 110, an ejector rod 220, an ejector rod drive unit 210, a pass line lifter 320, a pass line lifter drive unit 310, a carrier transfer unit 410, an injection device 610, and an injection transfer unit 710 (see Figure 2).

The mold clamping drive unit 110 drives the mold clamping mechanism 10 to open and close the mold and clamp the mold. The ejector rod drive unit 210 sets the Z-direction height of the ejector rod 220. The pass line lifter drive unit 310 sets the Z-direction height of the pass line lifter 320, which supports the strip-shaped carrier 4 on a horizontal surface. The carrier transfer unit 410 transfers the strip-shaped carrier 4 in the extension direction. The injection transfer unit 710 (see Figure 2) sets the Z-direction height of the injection device 610.

The mold clamping mechanism 10 is composed of an upper platen portion 32, a lower platen portion 50, a mold clamping slider 36, tie bars 34, and a base portion 42.

The upper platen portion 32 is a plate-like member having a substantially rectangular shape in the XY plane and a predetermined thickness in the Z direction. The upper platen portion 32 is fixed to the lower surface of the upper platen portion 32, which faces the lower platen portion 50, at approximately the center of the rectangle. The upper platen portion 32 has an opening 33 that connects approximately the center of the upper surface of the upper platen portion 32 to approximately the center of the lower surface of the upper platen portion 32 and is connected in the Z direction. The opening 33 is a tapered opening with a larger diameter on the upper surface side of the upper platen portion 32 and a smaller diameter on the lower surface side of the upper platen portion 32. The opening 33 is used to insert the tip nozzle of the injection unit 610 during injection molding.

The lower platen unit 50 has a moving table 52 and a base plate 62. In the embodiment shown in Figure 1, the moving table 52 is an example of a disk-shaped rotary table that is circular in the XY plane and has a predetermined thickness in the Z direction. The base plate 62 is a plate-shaped member that supports the moving table 52, which is a rotary table, on its upper surface and is fixed to the frame 74 of the device. The moving table 52 is rotated by a motor fixed to the base plate 62 in the XY plane parallel to the upper surface of the base plate 62 around a rotation axis in the Z direction that passes through the center of the disk.

The lower mold 12 is mounted at a position a predetermined distance radially from the rotation axis of the movable table 52. In Figure 1, the rotation axis of the movable table 52 is located a predetermined distance in the +X direction of the figure (toward the viewer perpendicular to the paper) from the center of the lower mold 12, which is positioned opposite the upper mold 22. The lower mold 12 mounted on the movable table 52 rotates within the XY plane as the movable table 52 rotates. Even when the movable table 52 rotates, the height of the lower mold 12 in the Z direction does not change relative to the height of the base plate 62 or the frame 74 of the device, and remains at a constant height relative to the height reference plane 72 of the device.

The movable table 52 has a through hole 54 that penetrates the movable table 52 in the Z direction at a position that corresponds to approximately directly below the center of the mounted lower mold 12. Furthermore, the base plate 62 also has a through hole 64. The XY direction position of the through hole 64 in the base plate 62 coincides with the XY direction position to which the through hole 54 directly below the lower mold 12 moves when the movable table 52 moves the mounted lower mold 12 to a position facing the upper mold 22. In other words, Figure 1 shows that when the lower mold 12 mounted on the movable table 52 is in a position facing the upper mold 22, the through hole 54 in the movable table 52 and the through hole 64 in the base plate 62 are connected to form a through hole that penetrates the lower platen portion 50.

Now, turning to Figure 2, the relationship between the movable table 52 and the lower mold 12 mounted thereon will be further explained. Figure 2 shows an example in which the movable table 52 mounts multiple lower molds 12, with the lower mold 12a positioned opposite the upper mold 22 and the lower mold 12b positioned symmetrically to the lower mold 12a with respect to the rotation axis of the movable table 52. The movable table 52 can swap the lower mold 12a and lower mold 12b located in these two positions by rotating half a turn around the rotation axis.

The drive unit 510 is composed of a motor 512 that rotates the moving table 52, which is a rotary table, a fixture 514 that secures the motor 512 to the base plate 62, and a rotation shaft 516 that transmits the rotation of the motor 512 to the moving table 52. These are arranged on the underside of the base plate 62. As explained above, the rotation shaft 516 of the moving table 52 is located a predetermined distance in the +X direction from the center of the lower mold 12a, which is positioned opposite the upper mold 22, so there is space on the underside of the base plate 62 to arrange the drive unit 510, including the motor 512 and fixture 514.

The lower mold 12b is located symmetrically to the lower mold 12a with respect to the rotation axis 516 of the moving table 52, on the front side of the injection molding section 2. The lower mold 12b in this position can be used as the lower mold 12 for placing the individual insert parts 6. As shown in Figure 2, there is sufficient space above (+Z direction) and around (+X direction, ±Y direction) the lower mold 12b. Although not shown in the example of Figure 2, this space can be used to place, for example, a pick-and-place robot for placing the individual insert parts 6 in the appropriate position in the lower mold 12b, or a camera for inspecting whether the individual insert parts 6 are placed in the appropriate position in the lower mold 12b.

In addition, in the example shown in Figure 2, the height of the upper surface of the base plate 62 where the movable table 52 is located is lowered in part so that the upper surface of the movable table 52 and the upper surface of the base plate 62 are approximately flush with each other. This makes it easier to arrange equipment for installing the individual insert parts 6 in the lower mold 12b around the lower mold 12b.

Returning to Figure 1, we will continue explaining the mold clamping mechanism 10.

The mold clamping slider 36 is, for example, a plate-like member having a roughly rectangular shape in the XY plane and a predetermined thickness in the Z direction. A ball screw nut 38 having a central axis in the Z direction is fixed to the center of the rectangle on the mold clamping slider 36. The ball screw nut 38 moves in the Z direction, which is the direction of the central axis, in response to the rotation of the ball screw shaft. The mold clamping slider 36, which is fixed to the ball screw nut 38, also moves in the Z direction in response to the rotation of the ball screw shaft.

The tie bars 34 are cylindrical members extending in the Z direction. The upper end of the tie bar 34 is fixed to the upper platen portion 32, and the lower end is fixed to the mold clamping slider 36. As a result, the tie bars 34 set a constant Z-direction distance between the upper platen portion 32 and the mold clamping slider 36. While Figure 1 shows two tie bars 34, one on the left and one on the right, four tie bars 34 may be provided, connecting the corresponding four corners of the upper platen portion 32 and the mold clamping slider 36, which have a substantially rectangular shape in the XY plane. The tie bars 34 separate the upper platen portion 32 and the mold clamping slider 36 by a predetermined Z-direction distance and set them parallel to each other.

As shown in FIG. 1, the tie bars 34 penetrate the base plate 62 of the lower platen unit 50, but do not penetrate the movable table 52. This allows the movable table 52 to move within the XY plane even when it is on the base plate 62. The tie bars 34 connecting the corresponding four corners of the upper platen unit 32 and the mold clamping slider 36 are located symmetrically within the XY plane, a predetermined distance away from the center of each of the upper platen unit 32 and the mold clamping slider 36 in the direction of the four corners of the rectangle.

The tie bars 34 are similarly located symmetrically in the XY plane, a predetermined distance from the center of the lower mold 12, which is positioned opposite the upper mold 22 attached to the center of the upper platen portion 32, in the directions of the four corners of the rectangle. Meanwhile, the central axis of rotation of the movable table 52 is located at a distance of approximately the radius of rotation in the +X direction in Figure 1 from the center of the lower mold 12. By appropriately setting the distance to the four corners of the rectangle in the XY plane where the tie bars 34 are located and the radius of the disk of the movable table 52, the tie bars 34 are positioned outside the movable table 52, but not penetrating it.

The tie bars 34 pass through a base plate 62 fixed to the frame 74 of the device. A gap or an appropriate sliding mechanism is provided between the tie bars 34 and the base plate 62. This allows the tie bars 34 to move freely in the Z direction together with the upper platen portion 32 and mold clamping slider 36.

The base portion 42 is fixed to the height reference surface 72 and mounts the mold clamping drive unit 110. A ball screw bearing 48 is fixed to the base portion 42, which supports the ball screw shaft 116 of the mold clamping drive unit 110 and determines the direction of the screw shaft. The base portion 42 also has a guide hole 46 that penetrates in the Z direction from the top surface. When the mold clamping slider 36 moves in the Z direction together with the mold clamping mechanism 10, the guide rod 44 fixed to the mold clamping slider 36 slides in the Z direction along this guide hole 46. The guide rod 44 and guide hole 46 correct any wobble or twisting that occurs when the mold clamping mechanism 10 moves in the Z direction.

Next, the structure of the mold clamping drive unit 110 installed on the base unit 42 will be explained using Figure 2. In the injection molding unit 2 according to the embodiment, the components of the mold clamping drive unit 110 are mainly arranged in the front-to-rear direction of the device, i.e., the X direction, and will be explained using Figure 2.

The mold clamping drive unit 110 is composed of a servo motor 112, pulleys 113 and 114, a belt 115, a ball screw shaft 116, and other components. The servo motor 112 rotates its motor shaft while monitoring the rotation angle and rotation speed using an encoder attached to the motor. The rotation of the servo motor 112 is transmitted to the ball screw shaft 116 via pulleys 113 and 114 and the belt 115.

The ball screw shaft 116 is positioned by a ball screw bearing 48 attached to the base portion 42 so that the screw axis direction faces the Z direction (see also Figure 1). The mold clamping slider 36 fixed to the ball screw nut 38 moves in the Z direction in response to the rotation of the ball screw shaft 116, changing its height in the Z direction relative to the height reference surface 72. As a result, the upper mold 22 fixed to the upper platen portion 32 of the mold clamping mechanism 10 also changes its height in the Z direction relative to the height reference surface 72. Meanwhile, because the lower mold 12 is at a constant height relative to the height reference surface 72, the upper mold 22 moves open and closed and clamps relative to the opposing lower mold 12 in response to the rotation of the ball screw shaft 116.

The relationship between the amount of vertical movement of the upper mold 22 and the rotation angle and rotation speed of the servo motor 112 is determined by an encoder attached to the servo motor 112. Furthermore, based on the clamping force required to clamp the upper mold 22 and lower mold 12 together, the values required for the rotation force of the servo motor 112, the strength of the pulleys 113 and 114 and belt 115, the driving force of the ball screw shaft 116, and so on are determined. In the example shown, rotation is transmitted from the servo motor 112 to the ball screw shaft 116 via the pulleys 113 and 114 and belt 115, but other methods such as gears may also be used.

Returning to Figure 1, the configuration of the ejector rod 220 and ejector rod drive unit 210 will be explained.

In Figure 1, the ejector rod 220, which is located below the lower mold 12, is a straight, rod-shaped member of a predetermined length and strength. The lower end of the ejector rod 220 is supported by the slide portion 218 of the ejector rod drive unit 210, and the ejector rod 220 is installed so that the longitudinal direction of the rod is the Z direction. Furthermore, the XY direction position of the ejector rod 220 coincides with the XY direction positions of the through holes 54, 64 formed in the lower platen portion 50 when the lower mold 12 is positioned opposite the upper mold 22.

The ejector rod drive unit 210 is attached to the underside of the base plate 62 and has a servo motor 212 and a motion conversion unit consisting of a power transmission unit 214, a ball screw 216, and a slide unit 218. The example in Figure 1 shows two sets of ejector rod drive units 210 arranged axially symmetrically on either side of the ejector rod 220. That is, the left-side ejector rod drive unit 210 is rotated 180 degrees around the central axis of the right-side ejector rod 220. The slide units 218 of the ejector rod drive units 210 support the lower end of the ejector rod 220 from both the left and right sides.

The slide portion 218 of the ejector rod drive unit 210 moves in the Z direction along the screw axis of the ball screw 216. The ejector rod drive unit 210 sets the rotation of each servo motor 212 so that the Z-direction heights of the two left and right slide portions 218 are the same. The two sets of ejector rod drive units 210 move the ejector rod 220 in the Z direction while maintaining the longitudinal direction of the rod in the Z direction by supporting the lower ends of the ejector rods 220 at the same height with the two left and right slide portions 218. In this way, the ejector rod drive unit 210 sets the height of the tip of the ejector rod 220 in the through holes 54, 64 formed in the lower platen unit 50.

When activating the ejector 16 inside the lower mold 12 after injection molding, the ejector rod drive unit 210 sets the tip of the ejector rod 220 to a height that will allow it to pass through the through-holes 54, 64 of the lower platen portion 50 and reach the ejector 16 built into the lower mold 12. The ejector 16 is pushed up by the ejector rod 220, pushing the injection-molded product 7 out of the lower mold 12. The ejector rod 220 is driven by two sets of servo motors 212 on the left and right of the ejector rod drive unit 210, and generates the upward thrust force required for the ejector 16 to remove the injection-molded product 7 from the mold.

When moving the moving table 52 during lower mold 12 replacement, the ejector rod drive unit 210 lowers the tip of the ejector rod 220 below the height of the underside of the moving table 52, allowing the moving table 52 to move. In other words, the ejector rod drive unit 210 retracts the ejector rod 220 from the through-hole 54 of the moving table 52.

When the lower mold 12 is replaced, the mold is in an open state, the mold clamping slider 36 of the mold clamping mechanism 10 is in its highest position in the Z direction, and the ejector rod 220 is in its lowest position in the Z direction. The length and movement stroke of the ejector rod 220 are set so that the lower end of the ejector rod 220 does not interfere with the upper surface of the mold clamping slider 36, the upper surface of the ball screw nut 38, the upper end of the ball screw shaft 116, etc. Also, as shown in FIG. 1, the ejector rod drive unit 210 is not positioned directly below the ejector rod 220, but is positioned laterally (in the X and Y directions) away from the ejector rod 220 to avoid interference with the mold clamping slider 36, ball screw nut 38, ball screw shaft 116, tie bar 34, etc. of the mold clamping mechanism 10.

Using the same Figure 1, the configuration of the pass line lifter 320 and pass line lifter drive unit 310 will be explained.

The pass line lifter 320 is composed of a carrier guide rail 326, a support base 324, a support rod 322, etc. The pass line lifter drive unit 310 is composed of a servo motor 312 and a motion conversion unit consisting of a ball screw 316 and a slide unit 318.

The carrier guide rails 326 are two rail-shaped components that are long in the Y direction and spaced apart in the X direction by approximately the same distance as the strip width of the strip carrier 4. The carrier guide rails 326 support both ends of the strip carrier 4 in the strip width direction from the underside with the upper surfaces of the two rails, which are held horizontally. As a result, the carrier guide rails 326 keep the orientation of the strip surface of the strip carrier 4 in a horizontal plane, i.e., the XY plane. The carrier guide rails 326 determine the transport direction of the strip carrier 4 by setting the extension direction of the strip carrier 4 to the longitudinal direction of the carrier guide rails 326. Furthermore, the hoop-shaped insert parts 5 and injection-molded products 7 arranged on the strip carrier 4 are placed in the gap between the rails of the carrier guide rails 326 and transported along with the strip carrier 4.

The carrier guide rail 326 is connected to the slide portion 318 of the pass line lifter drive unit 310 via the support base 324 and support rod 322. The support rod 322 passes through an opening in the base plate 62 and can move freely in the Z-axis direction together with the support base 324 and carrier guide rail 326.

The pass line lifter drive unit 310 sets the Z-direction height of the carrier guide rail 326. The pass line lifter drive unit 310 moves the slide unit 318 in the Z-direction by rotating the ball screw 316 directly connected to the rotation shaft of the servo motor 312, thereby setting the Z-direction height of the strip-shaped carrier 4 supported by the carrier guide rail 326.

The pass line lifter drive unit 310 sets the height of the strip-shaped carrier 4 supported by the carrier guide rail 326 to a height at which the strip-shaped carrier 4 is transported in the extension direction during mold opening, and to a height at which the hoop-shaped insert part 5 is placed in the lower mold 12 during mold closing. During mold closing, the carrier guide rail 326 supporting the strip-shaped carrier 4 fits into the lower mold 12 with nearly zero clearance.

One set of pass line lifter 320 and pass line lifter drive unit 310 is installed on the entrance side of the injection molding unit 2, i.e., the right side in Figure 1, and one set of pass line lifter 320 and pass line lifter drive unit 310 is installed on the exit side of the injection molding unit 2, i.e., the left side in Figure 1. As a result, the pass line lifter 320 and pass line lifter drive unit 310 determine the orientation of the strip surface of the strip carrier 4 in the range from the entrance to the exit of the injection molding unit 2, keep the Z-direction height constant, and set the transport direction of the strip carrier 4 in the Y direction.

Next, using Figure 2, we will explain the configuration of the carrier transfer unit 410, which is installed in a pair on each of the entrance and exit sides of the injection molding unit 2 (see Figure 1).

The carrier transfer section 410 is composed of a cylindrical pulley 414, a servo motor 412, a support table 418, etc. The carrier transfer section 410 is located behind the lower mold 12 (in the -X direction), and is composed of the support table 418 and servo motor 412 fixed to the base plate 62, and a pulley 414 fixed to the rotation shaft of the servo motor 412. When the mold is opened, the strip-shaped carrier 4 is set to the transfer height by the pass line lifter drive section 310, and the strip surface of the strip-shaped carrier 4 is sandwiched between the cylindrical side surface of the pulley 414 and the carrier guide rail 326.

In this state, the servo motor 412 of the carrier transfer unit 410 rotates the pulley 414 by a predetermined rotation angle. As the cylindrical pulley 414 rotates, the carrier transfer unit 410 advances the strip-shaped carrier 4 by hooking mark structures such as pilot holes arranged in the extension direction of the strip-shaped carrier 4 onto pin structures provided along the outer periphery of the pulley 414. The carrier transfer unit 410 is supported by the carrier guide rail 326 and transfers the strip-shaped carrier 4, whose height, strip surface orientation, and transfer direction are determined, by a predetermined feed amount.

Note that the transfer method of the carrier transfer unit 410 in this embodiment uses pins provided along the outer periphery of the pulley 414 and pilot holes arranged in the extension direction of the strip carrier 4, but the transfer method of the strip carrier 4 is not limited to this. A gripper feed transfer method may also be used, in which the strip surface of the strip carrier 4 is pinched from above and below and the strip carrier 4 is fed a predetermined amount at a time. Alternatively, a roll feed type transfer method may be used, in which the strip carrier 4 is fed a predetermined amount at a time by a rotating belt surface.

The configuration of the injection device 610 and injection movement section 710 will now be explained using the same Figure 2.

The injection device 610 is located above the mold clamping mechanism 10 and consists of an injection cylinder 612 and an injection drive unit 614. The injection cylinder 612 is equipped with a screw that transports resin pellets downward, a heater that melts the resin, and an injection chamber that stores the molten resin. The injection drive unit 614 is equipped with an injection motor that operates the screw of the injection cylinder 612, a temperature setting unit that sets the resin temperature, and a pressure setting unit that sets the injection amount and injection pressure of the resin in the injection chamber. The injection cylinder 612 injects molten resin at the resin temperature, injection amount, injection pressure, etc. that are set by the injection drive unit 614.

During injection molding, the upper mold 22 and lower mold 12 are clamped together, and the resin injection outlet at the bottom of the injection cylinder 612 is in close contact with the entrance to the flow path 24 on the top surface of the upper mold 22. Figure 3 shows a front view of the injection molding unit 2 at this time. The same parts of the device are designated by the same reference numerals as in Figures 1 and 2.

In the state shown in Figure 3, the mold clamping drive unit 110 lowers the mold clamping mechanism 10, and the upper mold 22 and lower mold 12 are clamped together. The ejector rod drive unit 210 sets the tip of the ejector rod 220 to a height directly below the lower mold 12. The pass line lifter drive unit 310 sets the strip carrier 4 supported by the pass line lifter 320 to a height at which the strip carrier 4 is sandwiched between the upper and lower molds and the hoop-shaped insert part 5 is placed in the mold. In the state shown in Figure 3, the injection cylinder 612 injects molten resin into the cavity space in the clamped mold to produce the injection-molded product 7.

Returning to Figure 2, the configuration of the injection movement section 710 will be explained.

The injection movement unit 710 is installed between the injection device 610 and the frame 74 on the back of the device. The injection movement unit 710 connects the injection device 610 to the frame 74 and moves the injection device 610 in the Z direction relative to the frame 74. The injection movement unit 710 is composed of a servo motor 712, a ball screw 716, and a slide unit 714. The servo motor 712 rotates the ball screw 716, which is directly connected to the rotation axis, to move the slide unit 714 in the Z direction. The slide unit 714 is connected to the injection device 610 and changes the height of the injection device 610 in the Z direction.

Next, the control unit 810 of the injection molding apparatus 1 will be described with reference to Figure 1.

The control unit 810 is composed of a CPU 812, a storage device 814, an IF (interface) 816, a driver 818, etc. The CPU 812 calls up programs and control parameters stored in the storage device 814 and controls the injection molding apparatus 1 in accordance with the programs. The storage device 814 stores programs and control parameters for controlling the injection molding apparatus 1. The IF 816 exchanges control information and setting information for the injection apparatus 610 between the control unit 810 and the injection drive unit 614. The IF 816 also exchanges input/output information between the control unit 810 and an external input/output device (not shown), such as a touch panel.

Driver 818 receives data related to the rotation angle and rotation speed of the motor shaft from the encoders of the servo motors provided at various locations in injection molding unit 2. Under the control of CPU 812, driver 818 sets the rotation angle and rotation speed of the motor shaft for the servo motors provided at various locations in injection molding unit 2.

The motor shafts of the servo motors installed in various locations in the injection molding section 2 are connected to the screw shafts of the ball screws in the motion conversion section, for example, by pulleys and belts. The ratio of the rotation angle and rotation speed between the motor shaft and the screw shaft of the ball screw is determined by the diameter ratio of the connected pulleys. In addition, the relationship between the rotation angle and rotation speed of the screw shaft of the ball screw and the amount of movement of the slide section that meshes with the ball screw is also predetermined based on the pitch of the ball screw threads, etc. In other words, the rotation angle and rotation speed of the servo motor motor shaft are determined according to the amount of movement of the slide section.

The rotation angle and number of rotations of the motor shaft are determined in advance for the amount of movement required to move the slide part to the target position, and the target number of rotations and target rotation angle are stored in the memory device 814. The CPU 812 controls the driver 818 based on data from the servo motor's encoder and the target number of rotations and target rotation angle data read from the memory device 814, to set the rotation angle and number of rotations of the motor shaft to the servo motor. As a result, the CPU 812 of the control unit 810 moves the slide parts at various locations in the injection molding unit 2 to the target positions.

(Injection molding method)
An example of an injection molding method will now be described using the injection molding apparatus 1 having the above structure. Figure 4 is a flow chart showing an example of the injection molding method performed by the injection molding unit 2 under the control of the control unit 810.

Steps S2 to S8 shown on the left side of Figure 4 are processes for the lower mold 12a that faces the upper mold 22, and step S9 shown on the right side of Figure 4 is a process for the lower mold 12b (see Figure 2) that does not face the upper mold 22. The arrows that run through steps S2 to S8 on the left and step S9 on the right indicate the flow of processes that are carried out at approximately the same time. The arrows that pass through the center of the figure and head from the lower left to the upper right, and the arrows that head from the lower right to the upper left, indicate the process (step S1) of moving the movable table 52 to exchange the lower mold 12a and lower mold 12b.

When the moving table 52 is moved, the mold is in an open state, and the mold clamping mechanism 10 and injection unit 610 are raised in the +Z direction. The pass line lifter 320 is raised, and the strip-shaped carrier 4 is separated from the lower mold 12 and upper mold 22. In addition, the height of the tip of the ejector rod 220 is set below the bottom surface of the moving table 52, and the ejector rod 220 is retracted from the through-hole 54 of the moving table 52.

Steps S2 to S8 for the lower mold 12a facing the upper mold 22 after the moving table 52 has completed moving will now be described. The control unit 810 controls the pass line lifter drive unit 310 to lower the pass line lifter 320 and place the hoop-shaped insert part 5 on the lower mold 12. At approximately the same time, the control unit 810 controls the ejector rod drive unit 210 to move the tip of the ejector rod 220 directly below the ejector 16 of the lower mold 12 (step S2).

Next, the control unit 810 controls the mold clamping drive unit 110 to lower the mold clamping mechanism 10. The upper mold 22 and lower mold 12a are closed and clamped, forming a cavity space inside the mold (step S3). In step S3, the control unit 810 controls the amount of descent of the mold clamping mechanism 10 based on the output of the encoder of the servo motor 112 of the mold clamping drive unit 110 until the lower surface of the upper mold 22 contacts the upper surface of the opposing lower mold 12a. After the lower surface of the upper mold 22 contacts the upper surface of the opposing lower mold 12a, the control unit 810 controls the rotational force (torque) of the servo motor 112 so that a predetermined mold clamping force is generated between the upper mold 22 and lower mold 12a.

Next, the control unit 810 controls the injection movement unit 710 to lower the injection device 610 and bring the resin injection port at the lower end of the injection cylinder 612 into close contact with the upper surface of the upper mold 22. Next, the control unit 810 controls the injection drive unit 614 to inject molten resin into the mold cavity space through the flow path 24 of the upper mold 22 (step S4). This combines the hoop-shaped insert parts 5 arranged on the strip-shaped carrier 4 and the individual insert parts 6 installed in the lower mold 12 within the mold, producing the injection-molded product 7.

Next, the control unit 810 controls the injection movement unit 710 to raise the injection unit 610. Furthermore, the control unit 810 controls the mold clamping drive unit 110 to raise the mold clamping mechanism 10, thereby opening the upper mold 22 and the lower mold 12a (step S5).

Next, the control unit 810 controls the ejector rod drive unit 210 to abut the tip of the ejector rod 220 against the ejector 16 of the lower mold 12a, thereby removing the injection-molded product 7 from the lower mold 12. Approximately synchronously with this, the control unit 810 controls the pass line lifter drive unit 310 to raise the pass line lifter 320 (step S6).

The control unit 810 synchronizes the impact operation of the ejector rod 220 and the start of the ascending operation of the pass line lifter 320 using the servo motor 212 of the ejector rod drive unit 210 and the servo motor 312 of the pass line lifter drive unit 310 (see Figure 1). The injection-molded product 7 released from the lower mold 12 rises in conjunction with the ascending operation of the strip carrier 4 by the pass line lifter 320, and leaves the lower mold 12 together with the strip carrier 4. This synchronized control of the servo motor 212 and servo motor 312 ensures that the injection-molded product 7 and strip carrier 4 are not subjected to excessive force from the lower mold 12 or the pass line lifter 320 when they are released from the lower mold 12 or when the strip carrier 4 is ascending.

As a result of the process in step 6, the strip carrier 4 is pressed against the cylindrical side surface of the pulley 414 of the carrier transfer section 410. The strip carrier 4 is sandwiched between the cylindrical side surface of the pulley 414 and the carrier guide rail 326, and is spaced apart from the lower mold 12 and the upper mold 22. This sets the distance between the lower mold 12 and the upper mold 22 required to transfer the strip carrier 4, on which the injection-molded products 7 are arranged, in the -Y direction of the injection molding section 2 (see Figure 1).

Next, the control unit 810 controls the ejector rod drive unit 210 to lower the tip of the ejector rod 220 below the underside of the moving table 52, thereby retracting the ejector rod 220 from the through-hole 54 of the moving table 52 (step S7).

Next, the control unit 810 controls the servo motor 412 of the carrier transfer unit 410 to transfer the strip-shaped carrier 4 in the extension direction of the strip-shaped carrier by a feed amount equivalent to the arrangement spacing of the hoop-shaped insert parts 5 (step S8).

Step S9 for the lower mold 12b (see Figure 2), which does not face the upper mold 22 and is shown on the right side of Figure 4, is carried out in parallel with steps S2 to S8 for the lower mold 12a. After the moving table 52 moves (step S1), the lower mold 12b is located on the front side of the injection molding unit 2. While steps S2 to S8 are being carried out for the lower mold 12a, an individual insert part 6 is placed on the lower mold 12b by, for example, a pick-and-place robot (step S9).

Through steps S2 to S8 on the lower mold 12a facing the upper mold 22, the injection molding device 1 combines, within the mold, individual insert components 6, which are signal terminals of the connector, with hoop-shaped insert components 5, which are nail components or ground components of the connector, using injected resin to produce a connector, which is an injection-molded product 7. The injection molding device 1 then removes the injection-molded products 7 from the mold and transports them out of the injection molding device 1 in a state where they are lined up at a predetermined interval on the strip-shaped carrier 4.

In step S9, the injection molding apparatus 1 places the individual insert part 6 to be used in the next injection molding into the lower mold 12b, which does not face the upper mold 22, while steps 2 to 8 are being performed on the lower mold 12a.

As described above, the injection molding apparatus 1 performs all of the processes, such as placing the insert parts, joining the insert parts through injection molding, removing the injection molded product, and transporting it using a carrier, as operations of the injection molding apparatus 1 controlled by the control unit 810. As a result, the injection molding apparatus 1 can minimize the gap time between each process, thereby shortening the injection molding cycle time.

Furthermore, by repeatedly performing the series of steps shown in Figure 4, the injection molding apparatus 1 can repeatedly produce connectors, which are injection-molded products 7 with multiple insert parts inserted, in a connected form on the strip-shaped carrier 4. This makes it possible for the injection molding apparatus 1 to mass-produce connectors by injection molding.

In the flow shown in Figure 4, the operation of lowering the pass line lifter 320 in step S2 and the operation of moving the ejector rod 220 are operations that can be performed simultaneously. By starting one operation, for example, the operation of moving the ejector rod 220, simultaneously with the other operation, for example, the operation of lowering the pass line lifter 320, it is possible to further shorten the time required for the process of step S2.

The operation of lowering the tip of the ejector rod 220 below the bottom surface of the movable table 52 in step S7 may be performed immediately after and consecutively with the ejection operation of the ejector 16 by the ejector rod 220 in step S6. This may further reduce the total time required for steps 6 and 7. Furthermore, by making the movable table 52 smaller and lighter as a result of the miniaturization of the injection molding apparatus 1, the time required to move the table 52 in step S1 may be reduced.
(First Modification)

Figure 5 shows an example configuration of an injection molding device according to a first modified example. The configuration, other than that relating to the moving table of the injection molding device, is the same as the example configuration of the embodiment already described using Figures 1 to 4. In Figure 5, parts that are the same as those in Figures 1 and 2 are given the same reference numerals, and their description will be omitted.

Figure 5 shows (a) and (b) cross-sectional views and (c) a plan view of the moving table 53, base plate 62, and lower mold 12 according to the first modified example. The cross-sectional views of Figures 5(a) and (b) show the AA cross section of the plan view shown in Figure 5(c). The cross-sectional view of Figure 5(a) shows a state in which the lower mold 12 is positioned opposite the upper mold 22. The cross-sectional view of Figure 5(b) shows a state in which the lower mold 12 is positioned not opposite the upper mold 22.

The moving table 53 according to the first modified example is an example of a rectangular, flat slide table that has a rectangular shape in the XY plane and a predetermined thickness in the Z direction. The moving table 53, which is a slide table, is supported on the upper surface of a base plate 62 that is fixed to the frame 74 of the device. The moving table 53, which is a slide table, moves linearly in the front-to-back directions of the device (±X directions) within the XY plane parallel to the upper surface of the base plate 62 by a drive unit (not shown) fixed to the base plate 62.

The lower mold 12 mounted on the movable table 53 moves between a position facing the upper mold 22 as shown in FIG. 5(a) and a position not facing the upper mold 22 as shown in FIG. 5(b) by moving the movable table 53. The lower mold 12 in a position facing the upper mold 22 is shown as lower mold 12a, and the lower mold 12 in a position not facing the upper mold 22 is shown as lower mold 12b. The injection molding apparatus 1 clamps the upper mold 22 to the lower mold 12a and performs injection molding. The injection molding apparatus 1 places the individual insert part 6 in the lower mold 12b.

The movable table 53 has a through hole 54 directly below the lower mold 12 to be mounted. The through hole 54 directly below the lower mold 12a, which is positioned opposite the upper mold 22, coincides in position in the XY plane with the through hole 64 provided in the base plate 62, and the through holes 54, 64 pass from the lower surface of the base plate 62 to the upper surface of the movable table 53. The ejector rod 220 passes through the through holes 54, 64 to activate the ejector 16 in the lower mold 12a. Meanwhile, the lower mold 12b is located on the front side of the injection molding unit 2 (+X direction) and can be used to install individual insert parts 6.

As described above, the injection molding apparatus 1 having the movable table 53 of the first modified example combines the individual insert parts 6 placed in the lower mold 12b with the hoop-shaped insert parts 5 arranged on the strip-shaped carrier 4 within the mold at the position of the lower mold 12a, and then removes the resulting injection-molded product 7 together with the strip-shaped carrier 4.

The injection molding apparatus 1 according to the first modification has one lower mold 12 mounted on a movable table 53, which is a slide table. When mold clamping and injection molding are performed at the position of the lower mold 12a, the lower mold 12b with the individual insert part 6 installed cannot be prepared. Therefore, the cycle time for the process of producing the injection-molded product 7 is longer than in the embodiment using the movable table 52, which is a rotary table. However, the injection molding apparatus 1 according to the first modification has the advantage of being able to reduce the initial mold cost compared to the embodiment using multiple (two) lower molds 12.
(Second Modification)

Figure 6 shows a second variant of the injection molding device. Other than the ejector rod 220 of the injection molding device and the parts related to its drive, the configuration is the same as the configuration of the embodiment already described using Figures 1 to 4. In Figure 6, parts that are the same as those in Figures 1 and 2 are given the same reference numerals and will not be described again.

The second modified example shown in Figure 6 shows an example in which a set of ejector rod drive units drives the ejector rod 220. In addition to the servo motor 212, power transmission unit 214, and ball screw 216, the ejector rod drive unit shown in Figure 6 also has a first slide unit 2182 on the ball screw 216 side, a second slide unit 2183 on the ejector rod 220 side, a connecting rod 2181 connecting the two, a support base 221 whose upper end is fixed to the base plate 62, and a guide 222 that slides the second slide unit 2183 in the Z direction.

The connecting rod 2181 is connected to the first slide portion 2182 and the second slide portion 2183 at one end and the other end, respectively, so that it can rotate and move in the X direction. Furthermore, the -Z direction end (lower end) of the support base 221 supports the connecting rod 2181 so that it can rotate around a fulcrum.

When the first slide portion 2182 moves up and down in the Z direction in response to the rotation of the ball screw 216, the second slide portion 2183, which is connected by the connecting rod 2181, slides downward and upward along the guide 222, with the lower end of the support base 221 as a fulcrum. The ejector rod 220 is fixed to the second slide portion 2183 with its longitudinal direction facing the Z direction, and moves in the Z direction in accordance with the downward and upward movement of the second slide portion 2183, changing the height of the tip of the ejector rod 220. As a result, the tip of the ejector rod 220 protrudes from the top surface of the movable table 52 to activate the ejector 16, or descends below the bottom surface of the movable table 52 to allow the movable table 52 to move.

The amount of movement of the tip of the ejector rod 220 in the Z direction and the ejection force on the ejector 16 are set using the principle of leverage, taking into account the distance from the first slide portion 2182 to the fulcrum at the lower end of the support base 221 and the distance from the fulcrum of the support base 221 to the second slide portion 2183. Also, in this second modified example, to avoid interference between the ejector rod drive unit and the mold clamping slider 36 of the mold clamping mechanism 10, the ejector rod drive unit is not positioned directly below the ejector rod 220, but is positioned away from it in the lateral direction (X and Y directions).

The injection molding apparatus 1 according to the second variant uses a set of ejector rod drive units to change the height of the tip of the ejector rod 220, thereby removing the injection-molded product 7 from the mold and moving the lower mold 12 using the moving table 52. As a result, the injection molding apparatus 1 according to the second variant can repeatedly produce injection-molded products 7 in which individual insert parts and hoop-shaped insert parts are combined within the mold.

The injection molding apparatus and injection molding method of the present invention have been described above using exemplary embodiments and their modifications. The present invention is not limited to the described embodiments and modifications, and various modifications are possible within the scope of the claims. Such modified forms are also included within the scope of the present invention.

REFERENCE SIGNS LIST 1...injection molding apparatus, 2...injection molding section, 4...strip-shaped carrier, 5...hoop-shaped insert part, 6...individual insert part, 7...injection-molded product, 10...mold clamping mechanism, 12, 12a, 12b...lower mold, 14...space, 16...ejector, 22...upper mold, 24...flow path, 32...upper platen section, 33...opening, 34...tie bar, 36...mold clamping slider, 38...ball screw nut, 42...base section, 44...guide rod, 46...guide hole, 48...ball screw bearing, 50...lower platen section, 52, 53...moving table, 54...through hole, 62...base plate, 64...through hole, 72...height reference surface, 74...frame, 110...mold clamping drive section, 112...servo motor, 113, 114...pulley, 115...belt, 116...ball screw shaft, 210 ...ejector rod drive unit, 212...servo motor, 214...power transmission unit, 216...ball screw, 218...slide unit, 2181...connecting rod, 2182...first slide unit, 2183...second slide unit, 220...ejector rod, 221...support base, 222...guide, 310...pass line lifter drive unit, 312...servo motor, 316...ball screw, 318...slide unit, 320...pass line lifter, 322...support rod, 324...support base, 326...carrier guide rail, 410...carrier transfer unit, 412...servo motor, 414...pulley, 418...support base, 510...drive unit, 512...motor, 514...fixture, 516...rotating shaft, 610...injection device, 612...injection cylinder, 614...injection drive unit, 710... Injection moving unit, 712... servo motor, 714... slide unit, 716... ball screw, 810... control unit, 812... CPU, 814... storage device, 816... IF (interface), 818... driver

Claims (7)

An injection molding apparatus that injects resin into a cavity space formed by opening and closing an upper mold and clamping the lower mold, in which individual insert parts and hoop-shaped insert parts arranged on a strip-like carrier are placed, to produce an insert injection molded product corresponding to the shape of the cavity space, with the injection molded product arranged on the strip-like carrier ,
a lower platen unit including a moving table on which the lower mold is mounted and which moves the lower mold between at least two different positions, a position facing the upper mold and a position not facing the upper mold;
an ejector rod that is inserted into a through-hole that penetrates the lower platen portion when the lower mold is positioned opposite the upper mold;
a pass line lifter that sets the height and orientation of the strip surface of the strip carrier and the transport direction of the strip carrier;
a carrier transport unit that transports the strip-shaped carrier in an extension direction of the strip-shaped carrier by a predetermined feed amount,
an injection molding apparatus characterized in that the pass line lifter starts an operation of raising the height of the strip surface of the strip-shaped carrier in synchronization with the ejector rod pushing out the injection-molded product from the lower mold . An injection molding apparatus as described in claim 1, wherein the lower platen section includes a rotary table that mounts a plurality of the lower molds and rotates on a base plate. An injection molding apparatus as described in claim 1, wherein the lower platen section is equipped with a slide table that carries one of the lower molds and moves parallel on a base plate. An injection molding apparatus according to any one of claims 1 to 3, wherein the ejector rod and the pass line lifter are moved up and down by an ejector rod drive unit and a pass line lifter drive unit, respectively, each of which consists of a servo motor and a motion conversion unit. The injection molding apparatus of claim 4, wherein the ejector rod drive unit sets the height of the tip of the ejector rod in the through-hole of the lower platen portion. An injection molding apparatus as described in claim 4, wherein the pass line lifter drive unit sets the height of the strip carrier supported by the pass line lifter. An injection molding method using an injection molding apparatus for producing an insert injection molded product using a mold in which individual insert parts and hoop-shaped insert parts arranged on a strip-shaped carrier are placed, the injection molding apparatus comprising: a lower platen portion having a moving table for moving a lower mold; an ejector rod that is inserted into a through-hole that penetrates the lower platen portion when the lower mold is positioned opposite to the upper mold; a pass line lifter that supports the strip-shaped carrier and sets the height of the strip-shaped carrier; and a carrier transport portion that transports the strip-shaped carrier in an extension direction,
a first step of moving the lower mold on which the individual insert parts are placed to a position opposite the upper mold by the moving table;
a second step of setting the strip-shaped carrier supported by the pass line lifter to a height at which the hoop-shaped insert part is placed in the lower mold, and setting the tip of the ejector rod to a height inside the through-hole of the lower platen portion;
a third step of closing and clamping the upper mold to form a cavity space within the mold;
a fourth step of injecting a resin into the cavity to produce an injection-molded product;
A fifth step of moving the upper mold to open the mold.
a sixth step of pushing out the injection-molded product with the tip of the ejector rod and moving the strip-shaped carrier supported by the pass line lifter to the height of the carrier transfer section substantially in synchronization with the pushing out of the injection-molded product;
a seventh step of retracting the ejector rod from the through-hole of the moving table;
an eighth step of transporting the strip-shaped carrier by the carrier transport unit;
an injection molding method comprising the steps of: