Injection molding machine

Abstract

Provided is an injection molding machine capable of suppressing variation in the gap between the inner ring and the outer ring of a bearing. The injection molding machine is provided with: a holding member that holds a second mold that forms a mold cavity space together with a first mold; a rotating shaft that is disposed so as to project from the side of the holding member opposite the side on which the second mold is held, that is transmitted with the rotational force of the holding member, or that transmits the rotational force to the holding member; and a support member that rotatably supports the holding member via a bearing for embedding the rotating shaft, the holding member and the rotating shaft being disposed so that the first face of the holding member, which is the face of the holding member opposite the rotating shaft, and the second face of the rotating shaft, which is the face of the rotating shaft opposite the holding member, are in contact, a recess being formed in the rotating shaft, the recess being recessed from the second face and forming a gap with the first face, or a recess being formed in the holding member, the recess being recessed from the first face and forming a gap with the second face.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-212011, filed on December 5, 2024. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This invention relates to an injection molding machine. Background Technology

[0003] Patent document 1 describes an injection molding machine with the following configuration.

[0004] That is, the injection molding machine has: a mold closing device, a mold opening and closing device; a first ejection device for ejecting the first waste material formed in the mold device; a second ejection device for ejecting both the second molded product and the second waste material formed in the mold device; a first injection device for injecting molding material into the mold device; a second injection device for injecting molding material into the mold device; a first moving device for moving the first injection device forward and backward relative to the mold device; a second moving device for moving the second injection device forward and backward relative to the mold device; a control device for controlling the various components of the injection molding machine; and a frame for supporting the various components of the injection molding machine.

[0005] The mold closing device performs mold closing, pressure raising, mold closing, pressure release, and mold opening of the mold assembly. The mold assembly includes a fixed mold and a movable mold. Furthermore, the mold closing device has: a fixed pressure plate; a movable pressure plate configured to move freely relative to the mold closing device frame along the mold opening and closing direction; a rotary table rotatably supported by the movable pressure plate via a sliding plate; a rotation mechanism to rotate the rotary table; and a moving mechanism to move the movable pressure plate forward and backward relative to the fixed pressure plate.

[0006] The fixed pressure plate is fixed to the frame of the mold clamping device. The fixed mold is installed on the surface of the fixed pressure plate opposite to the movable pressure plate.

[0007] The movable pressure plate is configured to move freely relative to the mold clamping device frame along the mold opening and closing direction. A movable mold is mounted on the movable pressure plate opposite to the fixed pressure plate via a rotary table. The movable pressure plate includes: a front panel that rotatably supports the rotary table via a sliding plate; an intermediate block disposed radially inside the cylindrical portion of the rotary table; a gear constraint block disposed outside the intermediate block when viewed from the mold opening and closing direction; a rear block disposed behind the intermediate block; and a toggle rod mounting portion disposed on the rear end face of the rear block. Furthermore, the movable pressure plate rotatably supports the rotation axis of the rotary table via bearings.

[0008] The rotary table is rotatably mounted on a movable pressure plate via a sliding plate. The rotation center line of the rotary table is parallel to the mold opening and closing direction. A rotation mechanism rotates the rotary table. The rotation mechanism includes a rotary motor and a transmission mechanism that transmits the rotational driving force of the rotary motor to the rotary table.

[0009] Furthermore, in the injection molding machine configured as described above, during mold closing, the first movable molding surface of the movable mold and the first fixed molding surface of the fixed mold form a first cavity space, and the second movable molding surface of the movable mold and the second fixed molding surface of the fixed mold form a second cavity space. Molding material is supplied from the first injection unit to the first cavity space to form a first molded article. Next, mold opening occurs.

[0010] Next, the first ejection device ejects the first scrap material from the movable mold. This first scrap material is waste material that has solidified inside the mold assembly along with the first molded part. Then, the rotation mechanism rotates the rotary table 180°. As the rotary table rotates, the movable mold rotates 180°. At this time, the first molded part is not ejected from the movable mold, but rotates 180° together with it. Afterwards, the mold is closed.

[0011] During mold closing, the second movable molding surface and the first fixed molding surface form a first cavity space, and the first movable molding surface and the second fixed molding surface form a second cavity space. As described above, the first molded article is disposed in a portion of the second cavity space. Molding material is supplied from the second injection device to the remaining portion of the second cavity space to mold the second molded article. The first molded article is molded simultaneously with the second molded article. The first molded article is molded in the first cavity space. Then, the mold is opened.

[0012] Next, the second ejection device ejects both the second molded part and the second scrap from the movable mold. The second scrap is waste material that solidifies together with the second molded part inside the mold device. After being ejected from the movable mold, the second scrap separates from the second molded part. Simultaneously with the ejection of the second molded part and the second scrap, the first scrap is ejected. Afterward, the mold is opened, and the rotary table rotates 180° again.

[0013] Patent Document 1: Japanese Patent Application Publication No. 2021-84411

[0014] In recent years, the demand for injection molding machines that can use thermosetting resins as molding materials to mold articles has been increasing. When a thermosetting resin is used as the molding material, the temperature of the mold cavity increases, thus increasing the temperature transmitted to the holding member (a rotary table in Patent Document 1) or the rotating shaft used to hold the movable mold. If the temperature transmitted to the rotating shaft increases, the temperature of the inner ring of the bearing also increases. Therefore, the thermal expansion of the rotating shaft and the inner ring of the bearing relative to the thermal expansion of the outer ring of the bearing increases, and the gap between the inner and outer rings of the bearing decreases. Furthermore, if the gap between the inner and outer rings of the bearing decreases, the load on the rotary motor used to rotate the holding member of the movable mold increases.

[0015] On the other hand, for example, when molding begins in a cold state, shrinkage can cause the gap between the inner and outer rings of the bearing to increase. Furthermore, if the gap between the inner and outer rings of the bearing increases, the rotational accuracy of the retaining components or movable molds will deteriorate.

[0016] Therefore, if the clearance between the inner and outer rings of the bearing changes, it will cause changes in the load on the rotary motor, or a decrease in the rotational accuracy of the holding component or movable mold. Thus, it is preferable to suppress changes in the clearance between the inner and outer rings of the bearing. Summary of the Invention

[0017] The purpose of this invention is to provide an injection molding machine that can suppress changes in the gap between the inner and outer rings of a bearing.

[0018] The present invention, which achieves this objective, 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 configured to protrude toward a side of the holding member opposite to the side holding the second mold, and being transmitted a rotational force of the holding member, or transmitting a rotational force to the holding member; and a supporting member for rotatably supporting the holding member via a bearing for embedding the rotating shaft, the holding member and the rotating shaft being configured such that a first surface of the holding member opposite to the rotating shaft and a second surface of the rotating shaft opposite to the holding member are in contact, a recess is formed on the rotating shaft, the recess being recessed from the second surface and forming a gap with the first surface, or a recess is formed on the holding member, the recess being recessed from the first surface and forming a gap with the second surface.

[0019] Here, a through hole extending along the rotation center line may also be formed in the central part of the rotating shaft, and a recess may be formed on the rotating shaft, the recess extending from the through hole to the outer periphery from the second surface.

[0020] Furthermore, multiple recesses may be formed radially from the through hole.

[0021] Alternatively, a plurality of internal threads may be formed on the second surface of the rotating shaft, the internal threads being used to fasten the external threads of the fastening component used when connecting with the retaining component, and the recess being formed between the plurality of internal threads.

[0022] Furthermore, a through hole extending along the rotation center line may be formed in the central part of the rotating shaft, and a plurality of recesses may be formed on the retaining member, the recesses extending radially from the central part from the first surface.

[0023] Furthermore, a heat sink protruding inward from the inner surface of the through hole may also be provided on the rotating shaft.

[0024] Invention Effects

[0025] According to the present invention, an injection molding machine is provided that can suppress changes in the gap between the inner and outer rings of a bearing. Attached Figure Description

[0026] Figure 1 This is a diagram showing an example of the schematic structure of the injection molding machine according to the first embodiment.

[0027] Figure 2 This is a diagram showing an example of a cross-section of a movable pressure plate, a rotary table, etc.

[0028] Figure 3 This is an example of a perspective view of the rotation axis involved in the first embodiment, viewed from the front.

[0029] Figure 4 This is an example of a view of the rotary table according to the second embodiment, viewed from the rear along the centerline direction.

[0030] Figure 5 This is an example of a view of the rotation axis involved in the third embodiment, viewed from the front along the centerline direction.

[0031] In the diagram: 1, 2, 3 - Injection molding machine; 81 - Fixed mold (an example of mold 1); 82 - Movable mold (an example of mold 2); 100 - Mold closing device; 110 - Fixed pressure plate; 120 - Movable pressure plate (an example of support component); 370, 570 - Rotating shaft; 379 - Heat sink; 400 - Frame; 500 - Control device; 520 - Rotary table (an example of holding component); 528 - Bottom surface (an example of surface 1); 529, 575 - Recess; 550 - Bolt (an example of fastening component); 573 - Through hole; 574 - Internal thread; 576 - Front surface (an example of surface 2); 580 - Bearing. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] <First Embodiment>

[0034] Figure 1 This is a diagram showing an example of the schematic structure of the injection molding machine 1 according to the first embodiment. In the following description, it will sometimes be referred to as... Figure 1 The anterior side is simply referred to as the "anterior side". Figure 1 The inside side is simply referred to as the "inside side".

[0035] Figure 2 This is a diagram showing an example of a cross-section of the movable pressure plate 120, the rotary table 520, etc.

[0036] The injection molding machine 1 includes a mold assembly 80, a mold clamping assembly 100, a first ejector 201, a second ejector (not shown), a first injection unit 301, and a second injection unit (not shown). Furthermore, the injection molding machine 1 includes: a frame 400; a first moving device 401 for moving the first injection unit 301 relative to the mold assembly 80; a second moving device for moving the second injection unit relative to the mold assembly 80 (not shown); and a control device 500. The first ejector 201, the first injection unit 301, and the first moving device 401 are located near the front, while the second ejector, the second injection unit, and the second moving device are located on the inner side. 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 in the vertical direction. Therefore, Figure 1 The second ejection device, the second injection device, and the second moving device are not shown in the figure.

[0037] (Mold device 80)

[0038] The mold assembly 80 has a fixed mold 81 and a movable mold 82. An example is provided where the fixed mold 81 and the movable mold 82 are cuboids.

[0039] The fixed mold 81 has a first fixed forming surface 811 and a second fixed forming surface (not shown).

[0040] The movable mold 82 has a first movable forming surface 821 and a second movable forming surface (not shown).

[0041] Figure 1 The image shows the fixed mold 81 and the movable mold 82 in their open states. By closing the fixed mold 81 and the movable mold 82, a cavity space is formed between the fixed mold 81 and the movable mold 82.

[0042] (Mold closing device 100)

[0043] The mold clamping device 100 includes a fixed pressure plate 110, a movable pressure plate 120, a toggle seat 130, a tie rod 140, a toggle mechanism 150, a mold clamping motor 160, and a ball screw 170. Furthermore, the mold clamping device 100 includes a rotary table 520 rotatably supported on the movable pressure plate 120 relative to the fixed pressure plate 110; and a rotation mechanism 530 for rotating the rotary table 520. The mold clamping device 100 also includes a rotating shaft 570 mounted on the rotary table 520; and a bearing 580 rotatably supporting the rotary table 520 and the rotating shaft 570.

[0044] The fixed pressure plate 110 is fixed to the frame 400. On the surface of the fixed pressure plate 110 opposite to the movable pressure plate 120, a fixed mold 81 is installed in such a way that the first fixed forming surface 811 is near the front and the second fixed forming surface is inward.

[0045] The movable pressure plate 120 is configured to be able to move relative to the frame 400 along... Figure 1 The movable platen 120 moves in the left and right directions. A movable mold 82 is mounted on the surface of the movable platen 120 opposite to the fixed platen 110. The movable platen 120 moves relative to the fixed platen 110 along... Figure 1 The mold device 80 is moved left and right to perform mold closing, pressurization, mold clamping, demolding, and mold opening. In the mold clamping device 100, sometimes... Figure 1 The left and right directions are called the "mold opening and closing directions", and the direction of movement of the movable pressure plate 120 when the mold is closed is also called the "mold opening and closing direction". Figure 1 The direction to the right is called "front," and the direction of movement of the movable pressure plate 120 during mold opening is called "front." Figure 1 The left-hand direction is referred to as the "rear". The structure of the movable pressure plate 120 will be described in detail later.

[0046] The toggle seat 130 is configured to move along the mold opening and closing direction on the frame 400.

[0047] The tie rod 140 connects the fixed pressure plate 110 and the toggle seat 130 at a predetermined interval in the mold opening and closing direction. It is possible to provide multiple (e.g., 4) tie rods in the tie rod 140.

[0048] A toggle mechanism 150 is positioned between the movable pressure plate 120 and the toggle seat 130. The toggle mechanism 150 causes the movable pressure plate 120 to move relative to the toggle seat 130 in the mold opening and closing direction. The toggle mechanism 150 has a crosshead 151 and a pair of connecting rods 152. The crosshead 151 has a nut that mates with a ball screw 170. If the ball screw 170 rotates about its axis, the crosshead 151 moves relative to the toggle seat 130 in the mold opening and closing direction. This causes the connecting rods 152 to extend and retract, and the movable pressure plate 120 moves relative to the toggle seat 130 in the mold opening and closing direction.

[0049] The clamping motor 160 and the ball screw 170 are mounted on the toggle seat 130, thereby actuating the toggle mechanism 150. The ball screw 170 is driven by the rotation of the clamping motor 160 to rotate about the axis, and causes the crosshead 151 with the nut to move relative to the toggle support 130 in the mold opening and closing direction.

[0050] The movable pressure plate 120, the rotary table 520, the rotating mechanism 530, and the rotating shaft 570 are described below.

[0051] (Modible pressure plate 120)

[0052] The movable pressure plate 120 has a front panel 121 located at the frontmost side, a middle block 124, and a gear constraint block 125 located on the outer side of the middle block 124. Furthermore, the movable pressure plate 120 has a rear block 126 located behind the middle block 124, and a toggle rod mounting portion 128 located on the rear end face of the rear block 126.

[0053] For example, the movable pressure plate 120 can be formed by casting iron. In addition, the front panel 121, the middle block 124, the rear block 126 and the toggle rod mounting part 128 can be separate parts, or they can be formed into one piece by casting or other methods.

[0054] A first rod hole 122 is formed on the front panel 121, penetrating the front panel 121 in the mold opening and closing direction. A first ejector rod 211 is disposed in the first rod hole 122, and the first ejector rod 211 is movable in the mold opening and closing direction. Furthermore, a second rod hole (not shown) is formed on the front panel 121, penetrating the front panel 121 in the mold opening and closing direction. A second ejector rod (not shown) is disposed in the second rod hole (not shown), and the second ejector rod is movable in the mold opening and closing direction.

[0055] The intermediate block 124 is disposed inside the cylindrical portion 524 of the rotary table 520, which will be described later. An example is that the intermediate block 124 is cylindrical, with the column direction aligned with the center line. Furthermore, inside the intermediate block 124, spaces are formed for arranging the first ejector 201 and for arranging the second ejector (not shown).

[0056] A front panel 121 is mounted on the front end face of the intermediate block 124. Fitting recesses 127 for embedding the bearing 580 are formed on both the front panel 121 and the intermediate block 124. Sliding plates 610 are respectively provided on the front end face of the front panel 121, on the sides closer to the front and further inward than the fitting recesses 127. The sliding plates 610 are, for example, cuboid in shape and are fixed to the front panel 121 using bolts (not shown). It is possible that the material of the sliding plate 610 is softer than the disc portion 523 of the rotary table 520 (described later), for example, a copper alloy such as copper or brass.

[0057] The gear constraint block 125 is positioned in front of the rear block 126 and outside the middle block 124. The gear constraint block 125 constrains the driven gear 535 of the rotating mechanism 530 (described later) to move forward via the sliding plate 620. The gear constraint block 125 prevents the rotary table 520 from tilting.

[0058] The rear block 126 is located behind the intermediate block 124 and is supported by the pressure plate slider 190. For example, the rear block 126 can be a cuboid. Inside the rear block 126, spaces are formed for arranging the first ejector 201 and for arranging the second ejector. The intermediate block 124 is mounted on the front end face of the rear block 126.

[0059] The toggle lever mounting portion 128 is configured to protrude rearward from the rear end face of the rear block 126. The toggle lever mounting portion 128 is respectively provided at the upper and lower ends of the rear block 126. The toggle lever mounting portion 128 has multiple toggle lever mounting plates spaced apart in the horizontal direction, with their thickness direction facing horizontally. The front ends of each of the multiple toggle lever mounting plates have pin holes 129. A pin is inserted into the pin hole 129, and the connecting rod of the toggle mechanism 150 is oscillatingly mounted to the toggle lever mounting portion 128 via the pin.

[0060] (Rotating table 520)

[0061] The rotary table 520 is rotatably supported on the movable pressure plate 120 via the sliding plate 610. The rotation center line CL of the rotary table 520 is in the same direction as the mold opening and closing direction, and the position of the rotation center line CL is between the first movable forming surface 821 and the second movable forming surface (not shown) of the movable mold 82. In the following description, the mold opening and closing direction is sometimes referred to as the "center line direction". Furthermore, the side of the rotary table 520 with the rotation center line CL is sometimes referred to as the "inner side", and the side away from the rotation center line CL is sometimes referred to as the "outer side".

[0062] The rotary table 520 has a mold mounting section 521 for mounting a movable mold 82 and a winding section 522 for winding a flexible retainer 510. The rotary table 520 is located inside the multiple (e.g., 4) tie rods 140 to avoid interference with them.

[0063] Examples include the following: the mold mounting part 521 is a plate-shaped part perpendicular to the center line direction, for example, a cuboid shape.

[0064] The winding section 522 has a disc-shaped disc section 523 for fixing the mold mounting section 521, and a cylindrical section 524 extending rearward from the outer periphery of the disc section 523.

[0065] For example, the rotary table 520 can be formed by casting iron. In addition, the mold mounting part 521, the disc part 523 and the cylindrical part 524 can be separate parts, or they can be formed into one piece by casting or other methods.

[0066] The cylindrical portion 524 has a circumferential surface 525. A driven gear 535 of the rotating mechanism 530 (described later) is fixed along the entire circumferential direction of the circumferential surface 525. Furthermore, a flexible retaining member 510 is wound onto the circumferential surface 525.

[0067] One end of the flexible retainer 510 is fixed to the rotary table 520, and the other end is fixed to the movable pressure plate 120. For example, CABLEVEYOR (registered trademark) can be used as the flexible retainer 510.

[0068] (Rotating mechanism 530)

[0069] 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 driven gear 535.

[0070] The rotating mechanism 530 rotates the rotary table 520 between a first rotation angle and a second rotation angle. The first rotation angle is the rotation angle 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°. The second rotation angle is the rotation angle 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°.

[0071] In this embodiment, the rotating mechanism 530 reverses the direction in which the rotating table 520 rotates from the first rotation angle to the second rotation angle, compared to the direction in which it rotates from the second rotation angle to the first rotation angle. As a result, the wiring and conduit configuration fixed to the rotating table 520 is restored to its original state, making it easier to handle the wiring and conduit.

[0072] (Rotation axis 570)

[0073] The rotating shaft 570 is a cylindrical component. The rotating shaft 570 and the rotating table 520 are connected together by multiple bolts 550 (four in this embodiment). Furthermore, by embedding the rotating shaft 570 into a bearing 580 mounted on the movable pressure plate 120, the rotating shaft 570 and the rotating table 520 can rotate integrally relative to the movable pressure plate 120 via the bearing 580. Details regarding the connections between the rotating shaft 570 and the rotating table 520 and the rotating shaft 570 will be described in detail later.

[0074] The mold closing device 100 configured as described above performs the mold closing process, the pressure increasing process, the mold closing process, the pressure releasing process, and the mold opening process under the control of the control device 500.

[0075] During the mold closing process, the mold closing device 100 drives the mold closing motor 160 to rotate the ball screw 170, thereby causing the crosshead 151 to advance to the mold closing end position at a set moving speed. As a result, the movable pressure plate 120 advances and brings the movable mold 82 into contact with the fixed mold 81.

[0076] During the pressurization process, the mold closing device 100 further drives the mold closing motor 160, thereby causing the crosshead 151 to advance further from the mold closing end position to the mold closing position. As a result, a mold closing force is generated in the mold device 80.

[0077] In the mold closing process, the mold closing device 100 drives the mold closing motor 160, thereby maintaining the position of the crosshead 151 in the mold closing position. Thus, the mold closing force generated in the pressurization process can be maintained during the mold closing process. In the mold closing process, for example, with the rotary table 520 rotated to a first rotation angle, the first injection device 301 fills the 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 with liquid first molding material. By solidifying the filled first molding material, a first molded article is obtained. On the other hand, the second injection device fills the cavity space between the first molded article formed 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. By solidifying the filled second molding material, a second molded article containing the first molded article is obtained.

[0078] In the mold closing process, for example, when the rotary table 520 is rotated to the second rotation angle, the first injection device 301 fills the cavity space 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. By solidifying the filled first molding material, a first molded article is obtained. On the other hand, the second injection device fills the cavity space between the first molded article formed 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. By solidifying the filled second molding material, a second molded article containing the first molded article is obtained.

[0079] In the depressurization process, the mold closing device 100 drives the mold closing motor 160 to rotate the ball screw 170 in the opposite direction to the mold closing and pressurization processes described above, thereby causing the crosshead 151 to retract from the mold closing position to the mold opening start position. As a result, the movable pressure plate 120 retracts, and the mold closing force decreases. An example is given where the mold opening start position is the same as the mold closing end position described in the mold closing and pressurization processes.

[0080] During the mold opening process, the mold closing device 100 drives the mold closing motor 160 to cause the crosshead 151 to retract from the mold opening start position to the mold opening end position at a set moving speed. As a result, the movable pressure plate 120 retracts, and the movable mold 82 separates from the fixed mold 81.

[0081] (First ejection device 201, etc.)

[0082] The first ejection device 201 performs the ejection process under the control of the control device 500. The second ejection device also has the same structure as the first ejection device 201, and performs the ejection process under the control of the control device 500. The first ejection device 201 and the second ejection device are mounted on the movable pressure plate 120 and move together with the movable pressure plate 120 in the mold opening and closing direction. In the ejection process, the first ejection device 201 actuates the movable part provided on the movable mold 82, thereby ejecting the waste material from the movable mold 82 and separating it. Similarly, the second ejection device actuates the movable part provided on the movable mold 82, thereby ejecting the waste material and the second molded product from the movable mold 82 and separating them.

[0083] (Rotation axis 570, rotary table 520)

[0084] Figure 3 This is an example of a perspective view of the rotation axis 570 involved in the first embodiment, viewed from the front.

[0085] Figure 2 This is a diagram showing an example of a cross-section when the movable pressure plate 120, the rotary table 520, and the rotary shaft 570 are cut by a plane passing through the rotation center line CL and parallel to the vertical direction. Additionally, in Figure 2 In the middle, the upper half of the cross-section of the rotating shaft 570 is the part with the internal thread 574, which will be described later, and the lower half is the part with the recess 575, which will be described later.

[0086] The following uses Figure 2 and Figure 3 The details of the connection between the rotating shaft 570 and the rotating table 520 and the rotating shaft 570 are explained.

[0087] The rotating shaft 570 has: a base end portion 571, which consists of two cylindrical portions with different diameters, and is disposed on the side of the disk portion 523 of the rotary table 520 (in other words, the front side); and a shaft portion 572, disposed on the side opposite to the disk portion 523 relative to the base end portion 571 (in other words, the rear side). The center lines of the base end portion 571 and the shaft portion 572 are aligned, and the outer diameter of the base end portion 571 is larger than the outer diameter of the shaft portion 572. Furthermore, the shaft portion 572 of the rotating shaft 570 is embedded inside the inner ring of the bearing 580 mounted on the movable pressure plate 120, and the base end portion 571 is disposed closer to the disk portion 523 side than the inner ring of the bearing 580. Therefore, the center line of the shaft portion 572 is aligned with the aforementioned rotation center line CL.

[0088] A through hole 573 is formed in the center of the rotating shaft 570, extending along the center line.

[0089] Furthermore, an internal thread 574 for fastening the bolt 550 is formed on the front surface 576 of the rotating shaft 570 opposite to the disk portion 523. Multiple internal threads 574 are formed at equal intervals around the through hole 573 (in other words, around the rotation center line CL) (four in this embodiment).

[0090] Furthermore, a recess 575 is formed on the rotating shaft 570, recessed from the front surface 576. The recess 575 is formed in a straight line extending from the through hole 573 to the outer periphery. Moreover, multiple recesses 575 are formed radially from the through hole 573 (four in this embodiment). Each recess 575 is formed between multiple internal threads 574.

[0091] By forming a through hole 573 or multiple recesses 575 on the rotating shaft 570, the front surface 576 is divided into four small faces, or facets 577. Each facet 577 has a central angle of 90°, and a chamfer 578 is provided at the intersection of the two sides forming the central angle. For example... Figure 3 As shown, chamfer 578 is an example of an R chamfer. However, chamfer 578 can also be a C chamfer.

[0092] An insertion recess 527 is formed at the center of the disc portion 523 of the rotary table 520. The insertion recess 527 is recessed from the rear surface 526 of the movable pressure plate 120 opposite to the front panel 121 and is used to insert the base end portion 571 of the rotating shaft 570. The insertion recess 527 is cylindrical. The diameter of the insertion recess 527 is larger than the diameter of the base end portion 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.

[0093] Furthermore, a head recess 542 is formed in the center of the mold mounting portion 521 of the rotary table 520. The head recess 542 is recessed from the surface 541 on which the movable mold 82 is mounted and accommodates the head 552 of the bolt 550. An example is that the head recess 542 is cylindrical and its diameter is greater than or equal to the diameter of the insertion recess 527.

[0094] Furthermore, a through hole 543 is formed on the rotary table 520, which connects the insertion recess 527 with the head recess 542 and allows the external thread of the bolt 550 to pass through. Multiple through holes 543 are formed at equal intervals around the rotation center line CL, corresponding to the internal thread 574 of the rotation shaft 570 (four in this embodiment).

[0095] The rotating shaft 570 and the rotating table 520, as described above, are connected together by fastening the external thread of the bolt 550 passing through the through hole 543 to the internal thread 574 of the rotating shaft 570. Furthermore, when the rotating shaft 570 and the rotating table 520 are connected, the front surface 576 of the rotating shaft 570 contacts the bottom surface 528 of the insertion recess 527 of the rotating table 520.

[0096] The shaft portion 572 of the rotating shaft 570 is embedded inside the inner ring of the bearing 580.

[0097] The bearing 580 is embedded in the movable pressure plate 120. A fitting recess 127 is formed in the center of the front panel 121 and the intermediate block 124 of the movable pressure plate 120. The fitting recess 127 is used to insert and embed the bearing 580 from the front panel 121 side. The outer ring of the bearing 580 is pressed into the inner circumferential surface of the front panel 121 and the intermediate block 124 where the fitting recess 127 is formed. Examples of bearing 580 being a ball bearing or a roller bearing are possible.

[0098] Furthermore, a connecting hole 126h extending along the centerline is formed in the center portion of the middle block 124 and the rear block 126 of the movable pressure plate 120, allowing the fitting recess 127 to communicate with the outside. An example is provided where the connecting hole 126h is cylindrical, and the diameter of the connecting hole 126h is smaller than the diameter of the shaft portion 572 of the rotating shaft 570.

[0099] 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) that forms a cavity together with a fixed mold 81 (an example of a first mold). The injection molding machine 1 also includes a rotating shaft 570, which is configured to protrude from the side of the rotary table 520 opposite to the side holding the movable mold 82, and transmits rotational force from the rotary table 520. Furthermore, the injection molding machine 1 includes a movable pressure plate 120 (an example of a support member) that rotatably supports the rotary table 520 via a bearing 580 for engaging the rotating shaft 570. The rotary table 520 and the rotating shaft 570 are configured such that the bottom surface 528 (an example of a first surface) of the rotary table 520 opposite to the rotating shaft 570 and the front surface 576 (an example of a second surface) of the rotating shaft 570 opposite to the rotary table 520 are in contact. Furthermore, a recess 575 is formed on the rotating shaft 570, the recess 575 being recessed from the front surface 576 and forming a gap with the bottom surface 528 of the rotating table 520.

[0100] In the injection molding machine 1 configured as described above, since a recess 575 is formed on the rotating shaft 570, the contact area with the bottom surface 528 of the rotary table 520 is smaller compared to a structure without a recess 575 (hereinafter sometimes referred to as the "comparative structure"). In other words, at the location where the recess 575 is formed on the rotating shaft 570, air exists in the recess 575 between the bottom surface 528 of the rotary table 520 and the rotating shaft 570 (in other words, the rotary table 520 and the rotating shaft 570 are thermally isolated). As a result, in the injection molding machine 1, heat is difficult to conduct from the rotary table 520 to the rotating shaft 570. Therefore, in the injection molding machine 1, even if the rotary table 520 becomes hot due to filling the cavity space formed between the fixed mold 81 and the movable mold 82 with molding material, it is not easy for the rotating shaft 570 to become hot.

[0101] In injection molding machine 1, since the rotating shaft 570 is less likely to reach high temperatures, the inner ring of bearing 580 is also less likely to reach high temperatures compared to the comparative structure. In other words, injection molding machine 1 can reduce the heat transferred to the inner ring of bearing 580 compared to the comparative structure. Therefore, since the thermal expansion of the inner ring of bearing 580 is smaller than that of the comparative structure, even if the inner ring thermally expands, the gap between the outer ring and the inner ring of bearing 580 is larger than that of the comparative structure. Thus, according to injection molding machine 1, changes in the gap between the inner and outer rings of bearing 580 can be suppressed. Furthermore, the load (in other words, the torque of the rotary motor 531) during rotation caused by the thermal expansion of the inner ring of bearing 580 is smaller than that of the comparative structure.

[0102] When the thermal expansion of the inner ring of bearing 580 is large, in order to prevent the load from increasing during rotation caused by thermal expansion, it is advisable to set a larger gap between the inner and outer rings at room temperature. This ensures the desired gap remains even when the inner ring expands thermally. However, setting a larger gap at room temperature can lead to increased gap between the inner and outer rings of bearing 580 due to shrinkage, for example, when molding begins in a cold state. Furthermore, if the gap between the inner and outer rings of bearing 580 increases, the rotational accuracy of the rotary table 520 or the movable mold 82 deteriorates. In injection molding machine 1, compared to the comparative structure, the thermal expansion of the inner ring of bearing 580 is smaller, allowing for a smaller gap between the inner and outer rings at room temperature. In other words, according to injection molding machine 1, even in a cold state, changes in the gap between the inner and outer rings of bearing 580 can be suppressed. Furthermore, it can maintain the rotational accuracy of the rotary table 520 even when it is cold.

[0103] A through hole 573 extending along the centerline (an example of the direction of the rotation centerline) is formed in the central portion of the rotating shaft 570, and a recess 575 is formed therein, which extends from the through hole 573 to the outer periphery and is recessed from the front surface 576. This creates a space where the inner side of the rotating shaft 570 is continuous with the recess 575, thus preventing the air inside the recess 575 from becoming too hot. As a result, heat conducted from the rotary table 520 to the rotating shaft 570 or the inner ring of the bearing 580 is reduced. Furthermore, since the recess 575 is formed to extend from the central portion to the outer periphery, heat is also difficult to conduct to the outer periphery of the rotating shaft 570, thereby reducing the heat conducted to the inner ring of the bearing 580.

[0104] Furthermore, a connecting hole 126h is formed in the center of the middle block 124 and the rear block 126 of the movable pressure plate 120, allowing the fitting recess 127 to communicate with the outside. This creates a space where the outside of the movable pressure plate 120 is continuous with the recess 575 of the rotating shaft 570, thus preventing the air inside the recess 575 from becoming too hot. As a result, heat transfer from the rotary table 520 to the rotating shaft 570 or the inner ring of the bearing 580 is reduced.

[0105] Furthermore, in the injection molding machine 1, multiple recesses 575 are formed radially from the through holes 573. This ensures that the heat transferred via the front surface 576 of the rotating shaft 570 is not uneven in the circumferential direction.

[0106] Furthermore, a plurality of internal threads 574 are formed on the front surface 576 of the rotating shaft 570. These internal threads 574 are used to fasten the external threads of the bolts 550 (an example of a fastening component) used when connecting to the rotary table 520. Recesses 575 are formed between the plurality of threads 574. As a result, the rotating shaft 570 can be easily connected to the rotary table 520, and the heat transferred to the inner ring of the bearing 580 can be reduced.

[0107] Furthermore, in the aforementioned injection molding machine 1, a rotational force is applied to the rotary table 520 via a rotation mechanism 530, and the rotational force of the rotary table 520 is transmitted to the rotation shaft 570, but this method is not particularly limited. For example, it could also be structured such that a rotational force is applied to the rotation shaft 570, for example, via a motor, and the rotary table 520 is rotated by transmitting the rotational force to the rotary table 520 via the rotation shaft 570.

[0108] <Second Implementation>

[0109] The injection molding machine 2 according to the second embodiment differs from the injection molding machine 1 according to the first embodiment in that a recess 529 recessed from the bottom surface 528 is formed on the rotary table 520, while a recess 575 recessed from the front surface 576 is not formed on the rotation shaft 570. Hereinafter, the differences from the first embodiment will be described. In both the first and second embodiments, the same reference numerals are used for the same parts, and detailed descriptions are omitted.

[0110] Figure 4 This is an example of a view of the rotary table 520 according to the second embodiment, viewed from the rear along the centerline direction.

[0111] like Figure 4 As shown, a plurality of recesses 529 are formed on the rotary table 520 according to the second embodiment. Figure 4 (There are 4 in total), the recess 529 is recessed from the bottom surface 528 to the front side in a radial manner extending from the central portion. The recess 529 is formed among the plurality of through holes 543 in a manner different from the location where through holes 543 for the external thread of bolts 550 are formed.

[0112] On the other hand, in the second embodiment, no recess 575 is formed on the rotating shaft 570, and the front surface 576 is circular.

[0113] Therefore, a gap is formed between the recess 529 of the rotary table 520 and the front surface 576 of the rotary shaft 570.

[0114] In the injection molding machine 2 configured as described above, since a recess 529 is formed on the rotary table 520 according to the second embodiment, the contact area between the bottom surface 528 of the rotary table 520 and the front surface 576 of the rotating shaft 570 is smaller compared to the comparative structure. In other words, air exists in the recess 529 between the rotary table 520 and the rotating shaft 570 at the location where the recess 529 is formed (in other words, the rotary table 520 and the rotating shaft 570 are thermally isolated). As a result, in the injection molding machine 2, heat is difficult to conduct from the rotary table 520 to the rotating shaft 570. Therefore, in the injection molding machine 2, even if the rotary table 520 becomes hot due to filling the cavity space formed between the fixed mold 81 and the movable mold 82 with molding material, the rotating shaft 570 is less likely to become hot. As a result, the injection molding machine 2 can reduce the heat transferred to the inner ring of the bearing 580 compared to the comparative structure. Thus, according to the injection molding machine 2, it is possible to suppress changes in the gap between the inner and outer rings of the bearing 580.

[0115] Furthermore, in the injection molding machine 2, multiple recesses 529 are formed radially from the center. This ensures that the heat transferred via the front surface 576 of the rotating shaft 570 is not uneven in the circumferential direction.

[0116] Furthermore, a plurality of through holes 543 are formed on the rotary table 520, which are used to allow the external threads of the bolts 550 used for connection with the rotating shaft 570 to pass through, and recesses 529 are formed between the plurality of through holes 543. As a result, the rotating shaft 570 can be easily connected to the rotary table 520, and the heat transferred to the inner ring of the bearing 580 can be reduced.

[0117] <Third Implementation>

[0118] The injection molding machine 3 according to the third embodiment differs from the injection molding machine 1 according to the first embodiment in that the rotation axis 370 corresponding to the rotation axis 570 is different. Hereinafter, the differences from the first embodiment will be described. In both the first and third embodiments, the same reference numerals are used for the same parts, and detailed descriptions are omitted.

[0119] Figure 5 This is an example of a view of the rotation axis 370 involved in the third embodiment, viewed from the front along the centerline direction.

[0120] like Figure 5 As shown, the difference between the rotation shaft 370 in the third embodiment and the rotation shaft 570 in the first embodiment is that multiple (in) a plurality of rotation shafts are provided. Figure 5Four heat sinks 379 protrude inward from the inner surface of the through hole 573. Examples of heat sinks 379 can be provided, for example, throughout the entire area along the centerline of the through hole 573. Examples of heat sinks 379 can be provided where, if the through hole 573 is formed by machining, they are also machined. Alternatively, the heat sinks 379 can be joined to the inner circumferential surface of the through hole 573, for example, by welding, after being separately formed from the base end 571 or the shaft portion 572.

[0121] In the injection molding machine 3 configured as described above, heat from the rotating shaft 370 is dissipated via heat sink 379. Therefore, compared to the rotating shaft 570 of the first embodiment, the rotating shaft 370 is less prone to overheating. Furthermore, in the injection molding machine 3, when the rotating shaft 370 rotates, airflow is generated by the heat sink 379, allowing air in the recess 575 between the rotary table 520 and the rotating shaft 370 to easily exchange with air in the through hole 573. In other words, heat is easily dissipated from the recess 575. Therefore, compared to the injection molding machine 1 of the first embodiment, heat is less likely to be conducted from the rotary table 520 to the rotating shaft 570 in the injection molding machine 3. Thus, compared to the injection molding machine 1, the injection molding machine 3 can reduce the amount of heat transferred to the inner ring of the bearing 580. As a result, according to the injection molding machine 3, changes in the gap between the inner and outer rings of the bearing 580 can be suppressed.

[0122] Alternatively, a heat sink 379 protruding inward from the inner surface of the through hole 573 can be applied to the injection molding machine 2 according to the second embodiment. With the heat sink 379 in the rotating shaft 570 according to the second embodiment, compared to the injection molding machine 2 described above, the heat transferred to the inner ring of the bearing 580 can be further reduced, and changes in the gap between the inner and outer rings of the bearing 580 can be suppressed.

Claims

1. An injection molding machine, comprising: The retaining component holds the second mold, which together with the first mold forms the cavity space; A rotating shaft, configured to project toward a side of the retaining member opposite to the side holding the second mold, is either transmitted with the rotational force of the retaining member or transmits the rotational force to the retaining member; and The support member rotatably supports the retaining member via a bearing for embedding into the rotating shaft. The retaining member and the rotating shaft are configured such that the first surface of the retaining member opposite the rotating shaft and the second surface of the rotating shaft opposite the retaining member are in contact. A recess is formed on the rotating shaft, the recess being recessed from the second surface and forming a gap with the first surface; or a recess is formed on the retaining member, the recess being recessed from the first surface and forming a gap with the second surface.

2. The injection molding machine according to claim 1, wherein, A through hole is formed in the center of the rotating shaft, extending along the direction of the rotation center line, and a recess is formed on the rotating shaft, the recess extending from the through hole to the outer periphery from the second surface.

3. The injection molding machine according to claim 2, wherein, The recesses are formed radially from the through hole in multiple shapes.

4. The injection molding machine according to claim 2, wherein, A plurality of internal threads are formed on the second surface of the rotating shaft. The internal threads are used to fasten the external threads of the fastening component used when connecting with the retaining component. The recess is formed between the plurality of internal threads.

5. The injection molding machine according to claim 1, wherein, A through hole is formed at the center of the rotating shaft, extending along the rotation center line. A plurality of recesses are formed on the retaining member, the recesses extending radially from the central portion from the first surface.

6. The injection molding machine according to any one of claims 2 to 5, wherein, A heat sink protruding inward from the inner surface of the through hole is provided on the rotating shaft.

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