Injection molding machine

Abstract

To suppress variations in the thickness of molded products with a simple configuration. [Solution] An injection molding machine comprising: a holding member for holding a second mold which forms a cavity space together with a first mold; a rotating shaft which is positioned to protrude from the side of the holding member opposite to the side that holds the second mold, and to which the rotational force of the holding member is transmitted or to which rotational force is transmitted to the holding member; a support member which rotatably supports the holding member via a bearing into which the rotating shaft is fitted; and a restraining part which is attached to the support member and restrains the rotating shaft from moving toward the opposite side from the holding member.

Description

Technical Field

[0001] The present invention relates to an injection molding machine.

Background Art

[0002] Conventionally, an injection molding machine that compresses molten resin in a cavity during injection molding has been proposed. For example, Patent Document 1 describes an injection molding machine configured as described below. That is, a core driving device is provided on a movable platen, and a movable mold is attached to the core driving device. The core driving device includes an electric motor disposed on the side of the device, a rotating shaft provided parallel to the mold mounting surface, a pair of bevel gears that convert the axis of rotation in a right angle direction, and a rotating body that rotates thereby. This rotating body is housed in an opening formed in the center of the mold mounting surface of the core driving device and rotates a predetermined rotating member on the movable mold side. The rotation is converted into a linear motion by a ball screw mechanism in the movable mold to drive a compression core for compression molding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If the mold is deformed due to the pressure of the molding material filled in the cavity space during injection molding, the thickness of the molded product may vary. Therefore, it is desirable to suppress the deformation of the mold during injection molding. The injection molding machine described in Patent Document 1 has room for improvement in that the configuration is complicated, such as having a rotating shaft provided parallel to the mold mounting surface and a pair of bevel gears that convert the axis of rotation in a right angle direction. An object of the present invention is to provide an injection molding machine that can suppress variations in the thickness of a molded product with a simple configuration. [Means for solving the problem]

[0005] The present invention, completed with this objective in mind, is an injection molding machine comprising: a holding member for holding a second mold that forms a cavity space together with a first mold; a rotating shaft positioned to protrude from the side of the holding member opposite to the side that holds the second mold, and to which the rotational force of the holding member is transmitted or to which rotational force is transmitted to the holding member; a support member that rotatably supports the holding member via a bearing into which the rotating shaft is fitted; and a restraining part attached to the support member and which prevents the rotating shaft from moving toward the opposite side of the holding member. Here, the restraining portion is provided inside the support member so as to be movable in the axial direction of the rotating shaft and has an inner member that can contact the end of the rotating shaft opposite to the second mold, and the movement of the rotating shaft may be suppressed by pressing the rotating shaft by moving the inner member in the axial direction. Alternatively, the support member may have a fitting recess into which the bearing is fitted, and a communication hole on the opposite side of the fitting recess from the second mold that allows the fitting recess to pass through to the outside, and the rotating shaft has a shaft portion that is fitted into the bearing, and a tip portion that is provided on the opposite side of the shaft portion from the second mold and positioned in the communication hole, and the restraining portion may restrain the movement of the rotating shaft by blocking the opening of the communication hole so that the tip portion of the rotating shaft is not exposed from the communication hole. From another perspective, the present invention is an injection molding machine comprising: a holding member for holding a second mold that forms a cavity space together with a first mold; a rotating shaft positioned to protrude from the side of the holding member opposite to the side that holds the second mold, and to which the rotational force of the holding member is transmitted or to which rotational force is transmitted to the holding member; a support member that rotatably supports the holding member via a bearing into which the rotating shaft is fitted; an inner member provided inside the holding member and the rotating shaft, and capable of contacting the side of the second mold opposite to the first mold; and a restraining part attached to the support member, which prevents the inner member from moving to the side opposite to the second mold. Here, the suppression unit may begin suppressing movement before the molding material is filled into the cavity space, and then continue to suppress movement until the molding of the molded product is completed. Alternatively, the suppression unit may begin to suppress movement after the molding material has been filled into the cavity space, and continue to suppress movement until the molding of the molded product is completed. [Effects of the Invention]

[0006] According to the present invention, variations in the thickness of molded products can be suppressed with a simple configuration. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a schematic configuration of an injection molding machine according to the first embodiment. [Figure 2] This figure shows an example of a cross-section of a movable platen, a rotary table, etc. [Figure 3] This is an example of a perspective view of the rotation axis according to the first embodiment, viewed from the front. [Figure 4] This figure shows an example of a cross-section of an injection molding machine according to the second embodiment. [Figure 5] This figure shows an example of a cross-section of an injection molding machine according to the third embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings. <First Embodiment> Figure 1 is a diagram showing an example of the schematic configuration of an injection molding machine 1 according to the first embodiment. In the following description, the front side of Figure 1 may be simply referred to as the "front side," and the back side of Figure 1 may be simply referred to as the "back side." Figure 2 shows an example of a cross-section of the movable platen 120, the rotary table 520, etc. The injection molding machine 1 comprises a mold device 80, a clamping device 100, a first ejector device 201, a second ejector device (not shown), a first injection device 301, and a second injection device (not shown). The injection molding machine 1 also comprises a frame 400, a first moving device 401 for moving the first injection device 301 relative to the mold device 80, a second moving device (not shown) for moving the second injection device relative to the mold device 80, and a control device 500. The first ejector device 201, the first injection device 301, and the first moving device 401 are located on the front side, while the second ejector device, the second injection device, and the second moving device are located on the rear side. Furthermore, in the vertical direction of Figure 1, the positions of the first ejector device 201 and the second ejector device, the positions of the first injection device 301 and the second injection device, and the positions of the first moving device 401 and the second moving device overlap. For this reason, the second ejector device, the second injection device, and the second moving device are not shown in Figure 1.

[0009] (Mold device 80) The mold apparatus 80 includes a fixed mold 81 and a movable mold 82. The fixed mold 81 and the movable mold 82 can be exemplified as rectangular parallelepipeds. The fixed mold 81 has a first fixed molding surface 811 and a second fixed molding surface (not shown). The movable mold 82 has a first movable molding surface 821 and a second movable molding surface (not shown). Figure 1 shows the fixed mold 81 and the movable mold 82 in the open state. When the fixed mold 81 and the movable mold 82 are closed, a cavity space is formed between the fixed mold 81 and the movable mold 82.

[0010] (mold clamping device 100) The clamping device 100 comprises a fixed platen 110, a movable platen 120, a toggle support 130, a tie bar 140, a toggle mechanism 150, a clamping motor 160, and a ball screw 170. The clamping device 100 also comprises a rotary table 520 rotatably supported by the movable platen 120 relative to the fixed platen 110, and a rotation mechanism 530 for rotating the rotary table 520. The clamping device 100 also comprises a rotating shaft 570 attached to the rotary table 520, and bearings 580 that rotatably support the rotary table 520 and the rotating shaft 570. The clamping device 100 also comprises a pressurizing section 590 that pressurizes the end of the rotating shaft 570 opposite to the side attached to the rotary table 520.

[0011] The fixed platen 110 is fixed to the frame 400. A fixed mold 81 is attached to the surface of the fixed platen 110 facing the movable platen 120 such that the first fixed molding surface 811 is on the front side and the second fixed molding surface is on the back side.

[0012] The movable platen 120 is mounted on the frame 400 so as to be movable in the left-right direction in Figure 1. A movable mold 82 is attached to the surface of the movable platen 120 facing the fixed platen 110. By moving the movable platen 120 relative to the fixed platen 110 in the left-right direction in Figure 1, the mold device 80 performs mold closing, pressure increasing, mold clamping, depressurization, and mold opening. In the mold clamping device 100, the left-right direction in Figure 1 is referred to as the "mold opening / closing direction," and the direction of movement of the movable platen 120 when the mold is closed (to the right in Figure 1) is sometimes referred to as "forward," and the direction of movement of the movable platen 120 when the mold is open (to the left in Figure 1) is sometimes referred to as "rear." The configuration of the movable platen 120 will be described in detail later.

[0013] The toggle support 130 is mounted on the frame 400 so as to be movable in the mold opening and closing direction. The tie bar 140 connects the fixed platen 110 and the toggle support 130 at a predetermined distance in the mold opening and closing direction. It can be exemplified that multiple tie bars (for example, four) are provided.

[0014] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130. And the toggle mechanism 150 moves the movable platen 120 in the mold opening / closing direction with respect to the toggle support 130. The toggle mechanism 150 has a crosshead 151 and a pair of link groups 152. The crosshead 151 has a nut for the ball screw 170. When the ball screw 170 rotates about its axis, the crosshead 151 moves in the mold opening / closing direction with respect to the toggle support 130. Thereby, the link group 152 flexes, and the movable platen 120 moves in the mold opening / closing direction with respect to the toggle support 130.

[0015] The mold clamping motor 160 and the ball screw 170 are attached to the toggle support 130 and operate the toggle mechanism 150. The ball screw 170 rotates about its axis under the rotational drive of the mold clamping motor 160, and moves the crosshead 151 having a nut in the mold opening / closing direction with respect to the toggle support 130.

[0016] Hereinafter, the movable platen 120, the rotary table 520, the rotation mechanism 530, the rotating shaft 570, etc. will be described. (Movable platen 120) The movable platen 120 has a front panel 121 provided at the foremost side, an intermediate block 124, and a gear restraint block 125 disposed outside the intermediate block 124. Further, the movable platen 120 has a rear block 126 provided behind the intermediate block 124, and a toggle link attachment portion 128 provided at the rear end surface of the rear block 126. The movable platen 120 can be exemplified as being formed of, for example, cast iron. Note that the front panel 121, the intermediate block 124, the rear block 126, and the toggle link attachment portion 128 may be separate bodies, or may be integrally formed by casting or the like.

[0017] A first rod hole 122 is formed in the front plate 121, penetrating the front plate 121 in the mold opening and closing direction. A first ejector rod 211 is positioned in the first rod hole 122 so as to be movable in the mold opening and closing direction. A second rod hole (not shown) is also formed in the front plate 121, penetrating the front plate 121 in the mold opening and closing direction. A second ejector rod (not shown) is positioned in the second rod hole (not shown) so as to be movable in the mold opening and closing direction.

[0018] The intermediate block 124 is positioned inside the cylindrical portion 524 of the rotary table 520, which will be described later. The intermediate block 124 can be exemplified as being cylindrical in shape, for example, with the column direction being the direction of the centerline. Inside the intermediate block 124, a space is formed for the placement of the first ejector device 201 and a space for the placement of the second ejector device (not shown).

[0019] A front plate 121 is attached to the front end surface of the intermediate block 124. The front plate 121 and the intermediate block 124 have fitting recesses 127 into which bearings 580 are fitted. Slide plates 610 are provided on the front end surface of the front plate 121, both on the side in front of the fitting recess 127 and on the side behind the fitting recess 127. The slide plates 610 are, for example, rectangular parallelepipeds and are fixed to the front plate 121 using, for example, bolts (not shown). The material of the slide plates 610 can be exemplified as being softer than the disc portion 523 of the rotary table 520, which will be described later, for example, copper or a copper alloy such as brass.

[0020] The gear restraint block 125 is positioned in front of the rear block 126 and outside the intermediate block 124. The gear restraint block 125 restrains the forward movement of the passive gear 535 of the rotating mechanism 530 (described later) via the slide plate 620. The gear restraint block 125 suppresses the tilting of the rotary table 520.

[0021] The rear block 126 is located behind the intermediate block 124 and is supported by the platen carriage 190. The rear block 126 can be exemplified as, for example, a rectangular parallelepiped. Inside the rear block 126, there is a space for arranging the first ejector device 201 and a space for arranging the second ejector device. The intermediate block 124 is attached to the front end face of the rear block 126.

[0022] The toggle link mounting portion 128 is provided so as to protrude rearward from the rear end surface of the rear block 126. The toggle link mounting portion 128 is provided at both the upper and lower ends of the rear block 126. The toggle link mounting portion 128 has a plurality of toggle link mounting plates spaced horizontally, with the plate thickness direction facing the horizontal direction. Each of the plurality of toggle link mounting plates has a pin hole 129 at its tip. A pin is inserted through the pin hole 129, and the link of the toggle mechanism 150 is pivotably attached to the toggle link mounting portion 128 via the pin.

[0023] (Rotating table 520) The rotary table 520 is rotatably supported relative to the movable platen 120 via a slide plate 610. The direction of the rotational centerline CL of the rotary table 520 is the same as the mold opening and closing direction, and the position of the rotational centerline CL is between the first movable molding surface 821 and the second movable molding surface (not shown) of the movable mold 82. In the following description, the mold opening and closing direction may be referred to as the "centerline direction." Also, the side of the rotary table 520 that is on the rotational centerline CL side may be referred to as the "inside," and the side that is away from the rotational centerline CL may be referred to as the "outside."

[0024] The rotary table 520 has a mold mounting section 521 to which the movable mold 82 is attached, and a winding section 522 to which the flexible holder 510 is wound. The rotary table 520 is installed inside the tie bars 140 so as not to interfere with the tie bars 140.

[0025] The mold mounting portion 521 is plate-shaped and perpendicular to the centerline direction, and can be exemplified by being rectangular parallelepiped-shaped. The winding section 522 has a disc-shaped disc portion 523 to which the mold mounting section 521 is fixed, and a cylindrical portion 524 that extends rearward from the outer circumference of the disc portion 523. The rotary table 520 may, for example, be made of cast iron. The mold mounting portion 521, the disc portion 523, and the cylindrical portion 524 may be separate parts, or they may be integrally formed by casting or other means.

[0026] The cylindrical portion 524 has a circumferential surface 525. A passive gear 535 of the rotating mechanism 530, described later, is fixed to the circumferential surface 525 over its entire circumference. A flexible holder 510 is also wound around the circumferential surface 525. The flexible holder 510 has one end fixed to the rotary table 520 and the other end fixed to the movable platen 120. Examples of flexible holders 510 include cable carriers (registered trademark).

[0027] (Rotation mechanism 530) The rotating mechanism 530 includes a rotating motor 531 and a transmission mechanism 532 that transmits the rotational driving force of the rotating motor 531 to the rotating table 520. The transmission mechanism 532 is composed of, for example, a drive gear 533, an intermediate gear 534, and a passive gear 535.

[0028] The rotating mechanism 530 rotates the rotary table 520 by a first rotation angle and a second rotation angle. The first rotation angle is the angle of rotation that forms a cavity space between the first movable molding surface 821 of the movable mold 82 and the first fixed molding surface 811 of the fixed mold 81. The first rotation angle is, for example, 0°. On the other hand, the second rotation angle is the angle of rotation that forms a cavity space between the second movable molding surface (not shown) of the movable mold 82 and the first fixed molding surface 811 of the fixed mold 81. The second rotation angle is, for example, 180°.

[0029] In this embodiment, the rotation mechanism 530 reverses the direction in which the rotary table 520 rotates from the first rotation angle to the second rotation angle, and the direction in which it rotates from the second rotation angle to the first rotation angle. This returns the arrangement of the wiring and piping fixed to the rotary table 520 to its original position, making it easier to route the wiring and piping.

[0030] The rotating shaft 570 is a cylindrical member. The rotating shaft 570 and the rotary table 520 are connected by multiple bolts 550 (four in this embodiment). The rotating shaft 570 is fitted into a bearing 580 attached to the movable platen 120, so that the rotating shaft 570 and the rotary table 520 can rotate integrally with respect to the movable platen 120 via the bearing 580. Details of the rotating shaft 570 and the pressurizing part 590 will be described later.

[0031] The mold clamping device 100, configured as described above, performs mold closing, pressure boosting, mold clamping, depressurization, and mold opening processes under the control of the control device 500. In the mold closing process, the clamping device 100 drives the clamping motor 160 to rotate the ball screw 170, moving the crosshead 151 forward at a set speed to the mold closing completion position. As a result, the movable platen 120 moves forward, and the movable mold 82 comes into contact with the fixed mold 81. In the pressure boosting process, the clamping device 100 further drives the clamping motor 160 to advance the crosshead 151 from the closed position to the clamping position. This generates a clamping force in the mold 80.

[0032] In the clamping process, the clamping device 100 drives the clamping motor 160 to maintain the position of the crosshead 151 in the clamping position. This maintains the clamping force generated in the pressurization process during the clamping process. In the clamping process, for example, when the rotary table 520 is rotated to a first rotation angle, the first injection device 301 fills the cavity space formed between the first movable molding surface 821 of the movable mold 82 and the first fixed molding surface 811 of the fixed mold 81 with liquid first molding material. The filled first molding material solidifies to obtain a first molded product. Meanwhile, the second injection device fills the cavity space formed between the first molded product molded on the second movable molding surface of the movable mold 82 and the second fixed molding surface of the fixed mold 81 with liquid second molding material. The filled second molding material solidifies to obtain a second molded product containing the first molded product.

[0033] In the clamping process, for example, when the rotary table 520 is rotated to the second rotation angle, the first injection device 301 fills the cavity space formed between the second movable molding surface of the movable mold 82 and the first fixed molding surface 811 of the fixed mold 81 with liquid first molding material. The filled first molding material solidifies to obtain the first molded product. Meanwhile, the second injection device fills the cavity space formed between the first molded product molded on the first movable molding surface 821 of the movable mold 82 and the second fixed molding surface of the fixed mold 81 with liquid second molding material. The filled second molding material solidifies to obtain the second molded product, which includes the first molded product.

[0034] In the depressurization process, the clamping device 100 drives the clamping motor 160 to rotate the ball screw 170 in the opposite direction to that of the mold closing and pressure boosting processes, causing the crosshead 151 to retract from the clamping position to the mold opening start position. This causes the movable platen 120 to retract, reducing the clamping force. The mold opening start position can be exemplified as being the same position as the mold closing completion position described in the mold closing and pressure boosting processes. In the mold opening process, the mold clamping device 100 drives the mold clamping motor 160 to retract the crosshead 151 from the mold opening start position to the mold opening completion position at a set movement speed. As a result, the movable platen 120 retracts, and the movable mold 82 is separated from the fixed mold 81.

[0035] (First ejector device 201, etc.) The first ejector device 201 performs the ejection process under the control of the control device 500. The second ejector device has the same configuration as the first ejector device 201 and also performs the ejection process under the control of the control device 500. The first ejector device 201 and the second ejector device are attached to the movable platen 120 and move together with the movable platen 120 in the mold opening and closing direction. In the ejection process, the first ejector device 201 operates a movable member provided on the movable mold 82 to eject and detach the unwanted product from the movable mold 82. Then, the second ejector device operates a movable member provided on the movable mold 82 to eject and detach the unwanted product and the second molded product from the movable mold 82.

[0036] (Rotating shaft 570, rotary table 520, pressurizing unit 590, control device 500, etc.) Figure 3 is an example of a perspective view of the rotation axis 570 as seen from the front according to the first embodiment. Figure 2 shows an example of a cross-section obtained when the movable platen 120, rotary table 520, and rotating shaft 570, etc., are cut by a plane that passes through the rotation centerline CL and is parallel to the vertical direction. The rotating shaft 570, rotary table 520, pressurizing unit 590, control device 500, etc. will be described below with reference to Figures 2 and 3.

[0037] The rotating shaft 570 has three cylindrical parts of different diameters: a base end 571, a shaft portion 572, and a tip end 573. The base end 571 is located on the disc portion 523 side (in other words, the front side) of the rotary table 520, the tip end 573 is located on the opposite side of the disc portion 523 from the base end 571 (in other words, the rear side), and the shaft portion 572 is located between the base end 571 and the tip end 573. The centerlines of the base end 571, shaft portion 572, and tip end 573 coincide, the outer diameter of the base end 571 is larger than the outer diameter of the shaft portion 572, and the outer diameter of the shaft portion 572 is larger than the outer diameter of the tip end 573. The rotating shaft 570 is configured such that the shaft portion 572 is fitted inside the inner ring of a bearing 580 attached to the movable platen 120, and the base end 571 is positioned on the disc portion 523 side of the inner ring of the bearing 580. Therefore, the center line of the shaft portion 572 coincides with the rotation center line CL described above. The tip portion 573 is positioned inside the communication hole 126h of the movable platen 120, which will be described later.

[0038] The rotating shaft 570 has a front surface 576, which is the surface facing the disc portion 523, into which the male threads of the bolt 550 are tightened. Multiple female threads (four in this embodiment) are formed at equal intervals around the rotational center line CL.

[0039] The disc portion 523 of the rotary table 520 has an insertion recess 527 formed in the center, into which the base end 571 of the recessed rotating shaft 570 is inserted from the rear surface 526, which is the surface facing the front plate 121 of the movable platen 120. The insertion recess 527 is cylindrical. The diameter of the insertion recess 527 is greater than or equal to the diameter of the base end 571 of the rotating shaft 570. The bottom surface 528 of the insertion recess 527 faces the front surface 576 of the rotating shaft 570.

[0040] Furthermore, the mold mounting portion 521 of the rotary table 520 has a head recess 542 formed in the center of the surface 541 to which the movable mold 82 is attached, for accommodating the head 552 of the recessed bolt 550. The head recess 542 is cylindrical, and its diameter is said to be greater than or equal to the diameter of the insertion recess 527.

[0041] Furthermore, the rotary table 520 has through-holes 543 through which the male threads of the bolts 550 pass, via insertion recesses 527 and head recesses 542. Multiple through-holes 543 (four in this embodiment) are formed at equal intervals around the rotation centerline CL to correspond to the female threads 574 of the rotating shaft 570.

[0042] The rotating shaft 570 and the rotating table 520, configured as described above, are connected by the male thread of the bolt 550 passing through the through hole 543 and tightening it onto the female thread 574 of the rotating shaft 570. When the rotating shaft 570 and the rotating table 520 are connected, the front surface 576 of the rotating shaft 570 and the bottom surface 528 of the insertion recess 527 of the rotating table 520 come into contact.

[0043] The rotating shaft 570 is fitted inside the inner ring of the bearing 580. The bearing 580 is fitted into the movable platen 120. In the central part of the front plate 121 and intermediate block 124 of the movable platen 120, a fitting recess 127 is formed into which the bearing 580 is inserted from the front plate 121 side and into which the bearing 580 is fitted. The outer ring of the bearing 580 is press-fitted into the inner circumferential surface of the front plate 121 and intermediate block 124 that form the fitting recess 127. The bearing 580 can be a ball bearing or a roller bearing, for example.

[0044] Furthermore, the movable platen 120 has a central communication hole 126h formed in the center of the intermediate block 124 and the rear block 126, which allows the fitting recess 127 to pass through to the outside. The communication hole 126h is cylindrical, and its diameter is less than or equal to the inner diameter of the inner ring of the bearing 580, and larger than the diameter of the tip 573 of the rotating shaft 570.

[0045] The pressurizing section 590 can be exemplified as a solenoid having a coil (not shown) and a plunger (not shown) inside the case 591, with a shaft 592 fixed to the plunger exposed from the case 591. In the pressurizing section 590, the case 591 is fixed to the rear end face of the movable platen 120 with the shaft 592 positioned in the communication hole 126h of the movable platen 120.

[0046] When the pressurizing section 590 is energized, it increases the amount of protrusion of the shaft 592 from the case 591, thereby pressurizing the rear end of the tip 573 of the rotating shaft 570. On the other hand, when the energizing section 590 is stopped, it decreases the amount of protrusion of the shaft 592 from the case 591, thereby stopping the pressurizing of the rear end of the tip 573 of the rotating shaft 570.

[0047] The control device 500 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) (not shown) which is a memory area for storing programs, and a RAM (Random Access Memory) (not shown) which is a program execution area. The control device 500 realizes various functions of the injection molding machine 1 by having the CPU execute programs stored in the ROM or a storage device such as an HDD (Hard Disk Drive) or semiconductor memory.

[0048] The control device 500 controls, for example, the supply of power to the pressurizing section 590. For example, in the mold clamping process described above, the control device 500 supplies power to the pressurizing section 590 so that the shaft 592 contacts the rear end of the rotating shaft 570 and pressurizes the rotating shaft 570 before the first injection device 301 fills the first molding material and the second injection device fills the second molding material. Subsequently, the control device 500 stops supplying power to the pressurizing section 590 so that the shaft 592 does not pressurize the rear end of the rotating shaft 570 after, for example, the mold clamping process is completed. For example, in the depressurization process, the control device 500 stops supplying power to the pressurizing section 590 at the same time as starting to drive the mold clamping motor 160.

[0049] As described above, the injection molding machine 1 includes a rotary table 520 (an example of a holding member) that holds a movable mold 82 (an example of a second mold) which forms a cavity space together with a fixed mold 81 (an example of a first mold). The injection molding machine 1 also includes a rotating shaft 570 that is positioned to protrude from the side of the rotary table 520 opposite to the side that holds the movable mold 82, and to which the rotational force of the rotary table 520 is transmitted. The injection molding machine 1 also includes a movable platen 120 (an example of a support member) that rotatably supports the rotary table 520 via a bearing 580 into which the rotating shaft 570 is fitted. The injection molding machine 1 also includes a pressurizing unit 590 (an example of a suppression unit) that is attached to the movable platen 120 and suppresses the movement of the rotating shaft 570 away from the rotary table 520.

[0050] In the injection molding machine 1 described above, the pressurizing unit 590 prevents the rotating shaft 570 from moving to the opposite side of the rotary table 520. This prevents deformation of the movable mold 82 due to the pressure of the molding material filling the cavity space. As a result, the injection molding machine 1 suppresses variations in the thickness of the molded product caused by deformation of the movable mold 82. Furthermore, the pressurizing unit 590 is configured to pressurize the rotating shaft 570, and the pressurized rotating shaft 570 pressurizes the rotary table 520 to prevent deformation of the movable mold 82, thus enabling the suppression of deformation of the movable mold 82 with a simple configuration.

[0051] The pressurizing section 590 is provided inside the movable platen 120 so as to be movable in the axial direction (in other words, in the direction of the centerline) of the rotating shaft 570, and has a shaft 592 (an example of an inner member) that can contact the end of the rotating shaft 570 opposite to the movable mold 82. By moving the shaft 592 in the axial direction, the rotating shaft 570 is pressurized and its movement is suppressed. As a result, the rotating shaft 570 can be pressurized with a simple configuration, and by clamping the mold with the fixed platen 110 and the movable platen 120, the rotary table 520 is subjected to pressure, and even if the rotating shaft 570 is pressurized, the rotating shaft 570 can support the rotary table 520.

[0052] The pressurizing unit 590 starts pressurizing the rotating shaft 570 before the molding material is filled into the cavity space, and continues to pressurize the rotating shaft 570 until the molding of the molded product is completed (for example, until the clamping motor 160 is driven in the depressurization process). In other words, the pressurizing unit 590 starts to suppress the movement of the rotating shaft 570 before the molding material is filled into the cavity space, and continues to suppress the movement of the rotating shaft 570 until the molding of the molded product is completed. This ensures that deformation of the movable mold 82 due to the pressure of the molding material filled into the cavity space is suppressed with high certainty.

[0053] The pressurizing unit 590 may start pressurizing the rotating shaft 570 after the molding material has been filled into the cavity space, and continue pressurizing the rotating shaft 570 until the molding of the molded product is completed. In other words, after the molding material has been filled into the cavity space, the pressurizing unit 590 starts to reduce (or suppress) the amount of movement of the rotating shaft 570 from its position before the molding material was filled into the cavity space, and then suppresses the movement of the rotating shaft 570 until the molding of the molded product is completed. After the molding material has been filled into the cavity space, by reducing the volume of the cavity space and compressing the molding material before the molding material solidifies, it is possible to suppress the occurrence of sink marks and improve the surface properties of the molded product. Furthermore, the pressurizing section 590 may pressurize the rotating shaft 570 when the movable mold 82 deforms due to the pressure of the molding material filling the cavity space, and may not pressurize the rotating shaft 570 when the movable mold 82 is not deformed. Furthermore, the pressurizing section 590 may also be a device that suppresses the movement of the rotating shaft 570 so as to support the rotating table 520 when the rotating table 520 moves toward the rotating shaft 570.

[0054] Furthermore, the configuration of the pressurizing section 590 is not limited to the solenoid described above. For example, the pressurizing section 590 may have a contact member (not shown) that can contact the rear end of the rotating shaft 570, and a moving mechanism (not shown) that moves the contact member in the direction of the centerline. The moving mechanism can be exemplified as a ball screw motor having a ball screw and a rotary motor that rotates the ball screw. In the moving mechanism, the rotary motor is fixed to the rear end face of the movable platen 120 with the ball screw positioned in the communication hole 126h of the movable platen 120. The contact member can be exemplified as a cylindrical member having a nut. The contact member is preferably positioned outside the ball screw within the communication hole 126h of the movable platen 120. In this way, even if the pressurizing section 590 is a ball screw mechanism, the rotating shaft 570 can be pressurized, so deformation of the movable mold 82 can be suppressed with a simple configuration.

[0055] Furthermore, the pressurizing unit 590 may be a hydraulic actuator having a cylinder, a piston housed within the cylinder, and a rod with the piston fixed to one end and the other end protruding from the cylinder, wherein the amount of rod protrusion can be changed by oil supplied into the cylinder. The moving mechanism is preferably such that the cylinder is fixed to the rear end surface of the movable platen 120, with the other end of the rod positioned so as to be in contact with the rear end of the rotating shaft 570 within the communication hole 126h of the movable platen 120. In this way, even if the pressurizing unit 590 is a hydraulic actuator, the rotating shaft 570 can be pressurized, so deformation of the movable mold 82 can be suppressed with a simple configuration.

[0056] Furthermore, although the pressurizing section 590 pressurizes the rear end of the tip portion 573 of the rotating shaft 570, the position at which the rotating shaft 570 is pressurized is not particularly limited. For example, a protrusion may be provided on the tip portion 573 of the rotating shaft 570, in the central part in the direction of the centerline (however, not limited to the central part), that protrudes outward from the outer peripheral surface, and the pressurizing section 590 may pressurize this protrusion. Furthermore, although the rotating shaft 570 is directly pressurized, the system is not limited to this configuration. For example, another member may be connected to the tip portion 573 of the rotating shaft 570 so as to protrude outward from its outer circumferential surface (for example, a cylindrical member may be press-fitted), and the pressurizing portion 590 may pressurize this other member.

[0057] Furthermore, in the injection molding machine 1 described above, the rotational shaft 570 is connected to the rotary table 520 by bolts 550, thereby transmitting the rotational force of the rotary table 520 to the rotational shaft 570. However, as long as the rotational force of the rotary table 520 is transmitted to the rotational shaft 570, the rotational shaft 570 and the rotary table 520 do not need to be connected. For example, the rotational force of the rotary table 520 may be transmitted to the rotational shaft 570 via a coupling attached to at least one of the rotary table 520 and the rotational shaft 570.

[0058] In the injection molding machine 1 described above, rotational force is applied to the rotary table 520 by the rotation mechanism 530, and the rotational force of the rotary table 520 is transmitted to the rotating shaft 570. However, the machine is not limited to this configuration. For example, rotational force may be applied to the rotating shaft 570 by, for example, a motor, and the rotating shaft 570 may transmit this rotational force to the rotary table 520, causing the rotary table 520 to rotate.

[0059] <Second Embodiment> Figure 4 shows an example of a cross-section of the injection molding machine 2 according to the second embodiment. The injection molding machine 2 according to the second embodiment differs from the injection molding machine 1 according to the first embodiment in that it applies pressure to the movable mold 82. The differences from the first embodiment will be described below. The same reference numerals are used for the same components in the first and second embodiments, and their detailed descriptions will be omitted.

[0060] The rotating shaft 270 according to the second embodiment differs from the rotating shaft 570 according to the first embodiment in that it does not have a tip portion 573, and that the through hole 273 in the direction of the centerline is formed in the central part. In addition, the rotating shaft 270 has a cylindrical bush 275 at the end of the through hole 273 on the side of the rotary table 220. The inner diameter of the bush 275 is smaller than the diameter of the rear end of the through hole 273.

[0061] The rotary table 220 according to the second embodiment differs from the rotary table 520 according to the first embodiment in that a through hole 221 running in the direction of the centerline is formed in the center, passing through the insertion recess 527 and the head recess 542. The diameter of the through hole 221 is larger than the inner diameter of the bush 275.

[0062] The injection molding machine 2 is provided inside the rotary table 220 and the rotary shaft 270, and has an inner member 290 capable of pressurizing the movable mold 82. The inner member 290 has two cylindrical parts with different diameters: a front part 291 positioned on the side of the movable mold 82 (in other words, the front side), and a rear part 292 positioned on the opposite side of the movable mold 82 from the front part 291 (in other words, the rear side). The diameter of the front portion 291 is less than or equal to the diameter of the bush 275, and the front portion 291 is positioned within the through hole 273 of the rotating shaft 270 and the through hole 221 of the rotary table 220. The diameter of the rear portion 292 is larger than the through-hole 273 of the rotating shaft 270 and smaller than the diameter of the communication hole 126h of the movable platen 120. The rear portion 292 is positioned within the communication hole 126h of the movable platen 120.

[0063] When the pressurizing section 590 is energized, it increases the amount of protrusion of the shaft 592 from the case 591, thereby pressurizing the rear end of the rear portion 292 of the inner member 290. On the other hand, when the energizing section 590 is stopped, it decreases the amount of protrusion of the shaft 592 from the case 591, thereby stopping the pressurizing of the rear end of the rear portion 292 of the inner member 290.

[0064] For example, in the mold clamping process, the control device 500 energizes the pressurizing section 590 so that the shaft 592 contacts the rear end of the inner member 290 and pressurizes the inner member 290 before the first injection device 301 fills the first molding material and the second injection device fills the second molding material. Subsequently, the control device 500 stops energizing the pressurizing section 590 so that the shaft 592 does not pressurize the rear end of the inner member 290, for example, after the mold clamping process is completed. For example, in the depressurization process, the control device 500 stops energizing the pressurizing section 590 at the same time as starting to drive the mold clamping motor 160.

[0065] As described above, the injection molding machine 2 includes a rotary table 220 that holds a movable mold 82 which forms a cavity space together with the fixed mold 81. The injection molding machine 2 also includes a rotating shaft 270 which is positioned to protrude from the side of the rotary table 220 opposite to the side that holds the movable mold 82 and to which the rotational force of the rotary table 220 is transmitted. The injection molding machine 2 also includes a movable platen 120 which rotatably supports the rotary table 220 via a bearing 580 into which the rotating shaft 270 is fitted. The injection molding machine 2 also includes an inner member 290 which is provided inside the rotary table 220 and the rotating shaft 270 and is capable of contacting the side of the movable mold 82 opposite to the fixed mold 81. The injection molding machine 2 also includes a pressurizing part 590 (an example of a suppression part) which is attached to the movable platen 120 and suppresses the movement of the inner member 290 away from the movable mold 82.

[0066] In the injection molding machine 2 described above, the pressurizing unit 590 prevents the inner member 290 from moving to the side opposite to the movable mold 82. This prevents deformation of the movable mold 82 due to the pressure of the molding material filling the cavity space. As a result, the injection molding machine 2 suppresses variations in the thickness of the molded product caused by deformation of the movable mold 82. Furthermore, the pressurizing unit 590 is configured to pressurize the inner member 290, and the pressurized inner member 290 pressurizes the movable mold 82 to prevent deformation of the movable mold 82, thus enabling the suppression of deformation of the movable mold 82 with a simple configuration.

[0067] <Third Embodiment> Figure 5 shows an example of a cross-section of the injection molding machine 3 according to the third embodiment. The injection molding machine 3 according to the third embodiment differs from the injection molding machine 1 according to the first embodiment in that it has a limiting section 390 instead of a pressurizing section 590. The differences from the first embodiment will be described below. The same reference numerals are used for the same components in the first and third embodiments, and their detailed descriptions will be omitted.

[0068] The limiting portion 390 differs from the pressurizing portion 590 according to the first embodiment in that it is configured to close the opening 126e of the communication hole 126h of the movable platen 120 so that the rear end of the rotating shaft 570 does not protrude from the rear end surface of the movable platen 120.

[0069] More specifically, the limiting unit 390 includes a movable member 392 having a flat plate-shaped lid portion 391, and a drive unit 393 that moves the movable member 392 in a direction perpendicular to the centerline direction (for example, a direction perpendicular to the plane of the paper in Figure 5). The drive unit 393 can be exemplified as a solenoid having a coil (not shown) and a plunger (not shown) inside a case 394, with a shaft (not shown) fixed to the plunger exposed from the case 394. The case 394 is fixed to the rear end face of the movable platen 120, and the shaft is connected to the movable member 392.

[0070] The limiting section 390 increases the amount of shaft protrusion from the case 394 when the drive unit 393 is energized, causing the movable member 392 to move in a direction perpendicular to the centerline. On the other hand, the limiting section 390 decreases the amount of shaft protrusion when the power supply to the drive unit 393 is stopped, causing the movable member 392 to return to its original position. Then, as shown in Figure 5, when the drive unit 393 is energized, the limiting section 390 causes the cover portion 391 of the movable member 392 to close the opening 126e of the communication hole 126h of the movable platen 120.

[0071] The movable platen 120 has a guide member 126g that guides the movement of the movable member 392 around the opening 126e of the communication hole 126h, and behind the opening 126e. The guide member 126g prevents the movable member 392 from moving in the direction of the centerline.

[0072] The control device 500 controls, for example, the supply of power to the limiting unit 390. For example, in the clamping process, the control device 500 supplies power to the drive unit 393 so that the lid portion 391 closes the opening 126e of the communication hole 126h of the movable platen 120 before the first injection device 301 fills the first molding material and the second injection device fills the second molding material. Subsequently, the control device 500 stops supplying power to the drive unit 393 so that the lid portion 391 of the movable member 392 does not close the opening 126e of the communication hole 126h of the movable platen 120 after, for example, the clamping process is completed. For example, in the depressurization process, the control device 500 stops supplying power to the drive unit 393 at the same time as starting to drive the clamping motor 160.

[0073] In the injection molding machine 3 configured as described above, when the first injection device 301 etc. fills the molding material, the lid portion 391 of the movable member 392 closes the opening 126e of the communication hole 126h of the movable platen 120, thereby suppressing the movement of the rotating shaft 570 to the rear. In other words, even if the rotating shaft 570 tries to move to the rear due to the pressure of the molding material filled in the cavity space, the movement of the rotating shaft 570 is suppressed by the lid portion 391, and the movement of the lid portion 391 is suppressed by the guide member 126g. In other words, the lid portion 391 of the movable member 392 restricts the movement of the end of the rotating shaft 570 opposite to the side connected to the rotary table 520. Therefore, deformation of the movable mold 82 due to the pressure of the molding material filled in the cavity space can be suppressed. As a result, the injection molding machine 3 suppresses variations in the thickness of the molded product caused by deformation of the movable mold 82. Furthermore, the limiting section 390 is configured to pressurize the rotating shaft 570, and the pressurized rotating shaft 570 pressurizes the rotary table 520 to prevent deformation of the movable mold 82, thus making it possible to suppress deformation of the movable mold 82 with a simple configuration.

[0074] In the third embodiment, the size of the tip portion 573 of the rotating shaft 570 in the direction of the centerline is set as follows. That is, if the lid portion 391 does not block the opening 126e of the communication hole 126h of the movable platen 120, the rear end of the tip portion 573 is set to protrude from the opening 126e of the communication hole 126h due to the pressure of the molding material filled in the cavity space. This makes it possible to pressurize the rear end of the rotating shaft 570 by blocking the opening 126e of the communication hole 126h of the movable platen 120 with the lid portion 391.

[0075] Furthermore, in the limiting section 390, the movement of the movable member 392 is not limited to the solenoid described above, but may also be carried out by the ball screw mechanism or hydraulic actuator described above. Furthermore, in the injection molding machine 2 according to the second embodiment, a limiting section 390 may be used instead of a pressurizing section 590. [Explanation of Symbols]

[0076] 1,2,3…Injection molding machine, 81…Fixed mold (example of first mold), 82…Movable mold (example of second mold), 100…Clamping device, 110…Fixed platen, 120…Movable platen (example of support member), 126h…Communication hole, 127…Matching recess, 220,520…Rotating table (example of holding member), 270,570…Rotating shaft, 290…Inner member, 390…Restricting part (example of suppression part), 400…Frame, 500…Control device, 572…Shaft part, 573…Tip part, 580…Bearing, 590…Pressurizing part (example of suppression part), 592…Shaft (example of inner member)

Claims

1. A holding member that holds the second mold which forms a cavity space together with the first mold, A rotating shaft is positioned to protrude from the side of the holding member opposite to the side that holds the second mold, and to transmit the rotational force of the holding member, or to transmit rotational force to the holding member. A support member that rotatably supports the holding member via a bearing into which the rotating shaft is fitted, A restraining part is attached to the support member and prevents the rotation shaft from moving to the opposite side from the holding member, An injection molding machine equipped with [a specific feature / feature].

2. The restraining portion is provided inside the support member so as to be movable in the axial direction of the rotating shaft and has an inner member that can contact the end of the rotating shaft opposite to the second mold, and the movement of the rotating shaft is suppressed by applying pressure to the rotating shaft by moving the inner member in the axial direction. The injection molding machine according to claim 1.

3. The support member has a fitting recess into which the bearing is fitted, and a communication hole on the side opposite to the second mold that allows the fitting recess to connect to the outside. The rotating shaft has a shaft portion that is fitted into the bearing, and a tip portion that is provided on the side opposite to the second mold relative to the shaft portion and is positioned in the communication hole. The restraining part suppresses the movement of the rotating shaft by blocking the opening of the communication hole so that the tip of the rotating shaft is not exposed from the communication hole. The injection molding machine according to claim 1.

4. A holding member that holds the second mold which forms a cavity space together with the first mold, A rotating shaft is positioned to protrude from the side of the holding member opposite to the side that holds the second mold, and to transmit the rotational force of the holding member, or to transmit rotational force to the holding member. A support member that rotatably supports the holding member via a bearing into which the rotating shaft is fitted, An inner member provided inside the holding member and the rotating shaft, and capable of contacting the surface of the second mold opposite to the first mold, A restraining part is attached to the support member and prevents the inner member from moving to the side opposite to the second mold, An injection molding machine equipped with [a specific feature / feature].

5. The suppression unit begins to suppress movement before the molding material is filled into the cavity space, and thereafter continues to suppress movement until the molding of the molded product is completed. An injection molding machine according to any one of claims 1 to 4.

6. The suppression unit begins to suppress movement after the molding material is filled into the cavity space, and continues to suppress movement until the molding of the molded product is completed. An injection molding machine according to any one of claims 1 to 4.

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