Injection molding machine

Abstract

The present invention provides 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 of the present invention includes a holding member that holds a second mold that forms a mold cavity space together with a first mold; a rotating shaft that is arranged to project toward the side of the holding member opposite the side that holds the second mold so as to transmit the rotational force of the holding member or transmit rotational force to the holding member; a support member that rotatably supports the holding member via a bearing that is embedded in the rotating shaft; and a temperature adjustment section that adjusts the temperature of the rotating shaft.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2024-212012, filed on December 5, 2024. The entire contents of that Japanese application are incorporated herein by reference.

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

[0003] Patent Document 1 describes an injection molding machine with the following configuration: The injection molding machine includes: a mold closing device; a mold opening and closing device; a first ejection device for ejecting a first waste material formed in the mold device; a second ejection device for ejecting both a second molded article 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.

[0004] 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.

[0005] The fixed pressure plate is fixed to the frame of the mold closing device. The fixed mold is installed on the surface of the fixed pressure plate opposite to the movable pressure plate.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] Patent Document 1: Japanese Patent Application Publication No. 2021-84411 Summary of the Invention

[0013] 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 that rotates the holding member of the movable mold increases.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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, so as to transmit rotational force of the holding member, or to transmit rotational force to the holding member; a supporting member for rotatably supporting the holding member via a bearing embedded in the rotating shaft; and a temperature regulating unit for regulating the temperature of the rotating shaft.

[0018] Here, the temperature regulating unit may also supply a heat medium to a hole formed inside the rotating shaft.

[0019] Alternatively, the following configuration may be used: multiple through holes are formed inside the rotating shaft, extending along the rotation center line; the temperature regulating unit supplies the heat medium to one of the multiple through holes and discharges the heat medium from the other through holes.

[0020] Furthermore, the temperature regulating unit can also supply the heat medium from the end of the support member side of one of the through holes, and discharge the heat medium from the end of the support member side of the other through holes.

[0021] Alternatively, the retaining member and the rotating shaft can be 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, and a recess is formed on the rotating shaft that extends from the second surface; or, a recess is formed on the retaining member that extends from the first surface, and the heat medium supplied to the one through hole moves through the recess to the other through hole.

[0022] Furthermore, it also includes a temperature detection unit for detecting the temperature of the rotating shaft, and the temperature adjustment unit can control the supply of the heat medium based on the temperature detected by the temperature detection unit.

[0023] Furthermore, it also includes a motor that applies a rotational driving force to the holding member and a torque detection unit that detects the torque of the motor. The temperature regulation unit can also control the supply of the heat medium based on the torque detected by the torque detection unit.

[0024] Alternatively, the temperature regulating unit may also have a heater disposed inside the rotating shaft.

[0025] Furthermore, it also includes a temperature detection unit for detecting the temperature of the rotating shaft, and the temperature adjustment unit can control the power supply to the heater based on the temperature detected by the temperature detection unit.

[0026] Invention Effects

[0027] 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

[0028] Figure 1 This is a diagram showing an example of the schematic structure of the injection molding machine according to the first embodiment.

[0029] Figure 2 This is a diagram showing an example of a cross-section of a movable pressure plate, a rotary table, etc.

[0030] Figure 3 This is an example of a partial cross-section of the rotating shaft involved in the first embodiment.

[0031] Figure 4 This is a diagram illustrating an example of the relationship between the temperature of a rotating shaft and the torque of a rotary motor.

[0032] Figure 5 This is an example of a view of the rotary table according to the second embodiment, viewed from the rear along the centerline direction.

[0033] Figure 6 This is an example of a partial cross-sectional view of the rotating shaft and temperature regulating unit according to the third embodiment.

[0034] In the picture:

[0035] 1, 2, 3 - Injection molding machine; 81 - Fixed mold (an example of the first mold); 82 - Movable mold (an example of the second mold); 100 - Mold closing device; 110 - Fixed pressure plate; 120 - Movable pressure plate (an example of a support component); 340 - Heater; 370, 570 - Rotary shaft; 390, 590 - Temperature control unit; 400 - Frame; 500 - Control device; 520 - Rotary table (an example of a holding component); 528 - Bottom surface (an example of the first surface); 531 - Rotary motor (an example of a motor); 573 - Through hole; 574 - Internal thread; 575, 529 - Recess; 576 - Front surface (an example of the second surface); 580 - Bearing; 595 - Thermocouple (an example of a temperature detection unit). Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] <First Embodiment>

[0038] 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".

[0039] Figure 2 This is a diagram showing an example of a cross-section of the movable pressure plate 120, the rotary table 520, etc.

[0040] 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.

[0041] (Mold device 80)

[0042] The mold assembly 80 includes a fixed mold 81 and a movable mold 82. An example is provided where both the fixed mold 81 and the movable mold 82 are cuboids.

[0043] The fixed mold 81 has a first fixed forming surface 811 and a second fixed forming surface (not shown).

[0044] The movable mold 82 has a first movable forming surface 821 and a second movable forming surface (not shown).

[0045] Figure 1 The image shows the fixed mold 81 and the movable mold 82 in their open states. When the fixed mold 81 and the movable mold 82 are closed, a cavity space is formed between them.

[0046] (Mold closing device 100)

[0047] 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. Finally, the mold clamping device 100 includes a temperature regulating unit 590, which regulates the temperature of the rotating shaft 570 by supplying a heat medium to the interior of the rotating shaft 570.

[0048] 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.

[0049] 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 1The left-hand direction is referred to as the "rear". The structure of the movable pressure plate 120 will be described in detail later.

[0050] The toggle seat 130 is configured to move along the mold opening and closing direction on the frame 400.

[0051] 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 tie rods 140 (e.g., 4 rods).

[0052] 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.

[0053] 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 seat 130 in the mold opening and closing direction.

[0054] The movable pressure plate 120, the rotary table 520, the rotating mechanism 530, and the rotating shaft 570 are described below.

[0055] (Modible pressure plate 120)

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The intermediate block 124 is disposed inside the cylindrical portion 524 of the rotary table 520, which will be described later. For example, the intermediate block 124 can be cylindrical with the column direction in the center line direction. Furthermore, inside the intermediate block 124, a space is formed for disposing of the first ejector 201 and a space for disposing of the second ejector (not shown).

[0060] A front panel 121 is mounted on the front end face of the intermediate block 124. Fitting recesses 127 for embedding bearings 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 than the fitting recesses 127 and the sides 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 plates 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.

[0061] 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.

[0062] 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 the second ejector. The intermediate block 124 is mounted on the front end face of the rear block 126.

[0063] 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.

[0064] (Rotating table 520)

[0065] 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".

[0066] The rotary table 520 has a mold mounting section 521 for mounting a movable mold 82 and a winding section 522 for winding up the flexible cable chain 510. The rotary table 520 is located inside the multiple (e.g., 4) tie rods 140 to avoid interference with them.

[0067] 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.

[0068] The winding section 522 has a disc-shaped disc section 523 that fixes the mold mounting section 521, and a cylindrical section 524 that extends rearward from the outer periphery of the disc section 523.

[0069] 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.

[0070] 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 cable chain 510 is wound onto the circumferential surface 525.

[0071] One end of the flexible cable chain 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 cable chain 510.

[0072] (Rotating mechanism 530)

[0073] 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.

[0074] 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°.

[0075] 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.

[0076] 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. Detailed descriptions of the rotating shaft 570 and the temperature regulating unit 590 will be provided later.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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 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. 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 formed 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] (First ejection device 201, etc.)

[0085] 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.

[0086] (Rotating shaft 570, rotating table 520, temperature regulating unit 590, control device 500, etc.)

[0087] Figure 3 This is an example of a partial cross-section of the rotating shaft 570 according to the first embodiment.

[0088] 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 through hole 573, which will be described later.

[0089] The following uses Figure 2 and Figure 3 The rotary shaft 570, rotary table 520, temperature regulating unit 590, control device 500, etc. are described.

[0090] 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.

[0091] A through hole 573 is formed on the rotating shaft 570, extending along the center line. Multiple through holes 573 are formed at equal intervals around the rotation center line CL (four in this embodiment).

[0092] Furthermore, an internal thread 574, which is the external thread of the fastening 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 rotation center line CL (four in this embodiment). The circumferential phase of the multiple internal threads 574 differs from the circumferential phase of the through holes 573, and the multiple internal threads 574 are formed at a position further outward than the multiple through holes 573.

[0093] Furthermore, a recess 575 is formed on the rotating shaft 570, recessed from the front surface 576. The recess 575 is formed between a plurality of through holes 573 so that the openings of the plurality of through holes 573 communicate with each other. In this embodiment, a recess 575 is formed that communicates with the openings of two of the four through holes 573, and a recess 575 that communicates with the openings of the remaining two of the four through holes 573.

[0094] Furthermore, an insertion hole 579 is formed on the rotating shaft 570, which extends from the rear side to the front along the center line direction, and a thermocouple 595 is inserted therein. The insertion hole 579 is formed over the entire area of ​​the shaft portion 572, and is formed outside the through hole 573 and at a position further inside than the outer peripheral surface of the shaft portion 572.

[0095] An insertion recess 527 is formed in 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, which faces the front panel 121, and is inserted into 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.

[0096] 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.

[0097] 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 in a manner corresponding to the internal thread 574 of the rotation shaft 570 (four in this embodiment).

[0098] 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.

[0099] The shaft portion 572 of the rotating shaft 570 is embedded inside the inner ring of the bearing 580.

[0100] 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 inserts into and embeds 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.

[0101] 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.

[0102] The temperature regulating unit 590 supplies heat medium to the through holes 573 formed inside the rotating shaft 570. For example, the temperature regulating unit 590 has a supply pipe 591, which supplies heat medium from the end of the movable pressure plate 120 of one of the two through holes 573 connected to the opening on the side of the disc portion 523 of the rotary table 525, which is connected to the recess 575. Furthermore, the temperature regulating unit 590 has a discharge pipe 592, which discharges heat medium from the end of the movable pressure plate 120 of the other two through holes 573 connected to the recess 575, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573, which is connected to the other through hole 573. Since four through holes 573 are formed on the rotating shaft 570 according to this embodiment, the temperature regulating unit 590 according to this embodiment has two supply pipes 591 and two discharge pipes 592.

[0103] Two supply pipes 591 and two discharge pipes 592 pass through the connecting hole 126h from the rear of the movable pressure plate 120 and are connected to the rotating shaft 570. The two supply pipes 591 are connected to a pump (not shown), which is controlled and driven by a control device 500.

[0104] According to the above structure, if the pump is driven, the hot medium is supplied to a through hole 573 of the rotating shaft 570 via the supply pipe 591. The hot medium supplied to the through hole 573 reaches other through holes 573 via the recess 575, and is discharged via the discharge pipe 592, reaching a tank (not shown). Furthermore, if the pump is stopped, the supply of hot medium to the rotating shaft 570 stops. Additionally, the case where the hot medium is water can be exemplified. Furthermore, the case where the pump or tank is fixed to the frame 400 can be exemplified.

[0105] The control device 500 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) (not shown) serving as a storage area for storing programs, and RAM (Random Access Memory) (not shown) serving as an execution area for programs. The control device 500 implements various functions of the injection molding machine 1 by causing the CPU to execute programs stored in storage devices such as ROM, HDD (Hard Disk Drive), or semiconductor memory. The control device 500 includes a motor drive unit (e.g., a frequency converter with transistors) that drives the rotary motor 531, and controls the drive of the rotary motor 531 by operating the motor drive unit. Furthermore, the control device 500 includes a pump drive unit (e.g., a transistor) that drives a pump supplying a heat medium, and controls the drive of the pump by operating the pump drive unit.

[0106] The temperature of the rotating shaft 570, detected by thermocouple 595, is input into the control device 500.

[0107] Furthermore, the control device 500 receives the detection result from a current sensor (not shown) that detects the current supplied to the rotary motor 531. An example is provided where the current sensor detects the value of the current flowing through the rotary motor 531 based on the voltage generated across a shunt resistor connected to the part supplying the current to the rotary motor 531. Since there is a correlation between the value of the current supplied to the rotary motor 531 and the torque of the rotary motor 531, the control device 500 uses the current detected by the current sensor to determine the torque of the rotary motor 531. In other words, the current sensor functions as a torque detection unit for detecting the torque of the rotary motor 531.

[0108] Furthermore, the control device 500 controls the supply of heat medium to the rotating shaft 570 based on the temperature of the rotating shaft 570 detected by the thermocouple 595 and the torque of the rotating motor 531 it controls.

[0109] Figure 4This is a diagram illustrating an example of the relationship between the temperature of the rotating shaft 570 and the torque of the rotating motor 531.

[0110] If the temperature of the rotating shaft 570 increases, the temperature of the inner ring of the bearing 580 will also increase, causing thermal expansion of the inner ring. This thermal expansion of the inner ring reduces the gap between the inner and outer rings, increasing the load resistance of the bearing 580 during rotation and consequently increasing the torque of the rotary motor 531. Therefore, there is a relationship between the temperature of the rotating shaft 570 and the torque of the rotary motor 531. Figure 4 The correlation shown is as follows. The ROM of the control device 500 stores in advance a reference torque of the rotary motor 531 relative to the temperature of the rotary shaft 570, which is determined based on the correlation between the temperature of the rotary shaft 570 and the torque of the rotary motor 531.

[0111] Furthermore, the control device 500 uses the temperature of the rotating shaft 570 detected by the thermocouple 595 to determine the reference torque, and drives the pump when the torque of the rotating motor 531, which is determined by the current detected by the current sensor, is greater than the reference torque. When the pump is driven, a hot medium is supplied to the interior of the rotating shaft 570 via the supply pipe 591, and the rotating shaft 570 is cooled. As a result, the inner ring of the bearing 580 is cooled, and the thermal expansion of the inner ring decreases. Consequently, the gap between the inner and outer rings of the bearing 580 increases.

[0112] 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). Furthermore, the injection molding machine 1 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, in order to transmit the rotational force of the rotary table 520. The injection molding machine 1 also includes a movable pressure plate 120 (an example of a support member) that rotatably supports the rotary table 520 via a bearing 580 embedded in the rotating shaft 570; and a temperature regulating unit 590 that regulates the temperature of the rotating shaft 570.

[0113] In the injection molding machine 1 configured as described above, since it has a temperature regulating unit 590 for adjusting the temperature of the rotating shaft 570, temperature fluctuations of the rotating shaft 570 can be suppressed compared to a structure without a temperature regulating unit 590 (hereinafter, sometimes referred to as a "comparative structure"). Therefore, according to the injection molding machine 1, fluctuations in the clearance between the inner and outer rings of the bearing 580 can be suppressed.

[0114] Here, given the large thermal expansion of the inner ring of bearing 580, to prevent the load from increasing during rotation due to 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, if the gap between the inner and outer rings at room temperature is set large, the inner ring will shrink during cold operation, increasing the gap between them and leading to a decrease in the rotational accuracy of the rotary table 520 or the movable mold 82. In injection molding machine 1, since a temperature regulating unit 590 is provided to adjust the temperature of the rotating shaft 570, cooling can be achieved by a heat medium if the temperature of the rotating shaft 570 increases. Therefore, according to injection molding machine 1, since the gap between the inner and outer rings at room temperature can be set smaller, the decrease in rotational accuracy of the rotary table 520 during cold operation can be suppressed.

[0115] The temperature regulating unit 590 of this embodiment supplies a heat medium to a hole (e.g., a through hole 573) formed inside the rotating shaft 570. As a result, the temperature of the rotating shaft 570 can be regulated with higher precision.

[0116] More specifically, a through hole 573 is formed inside the rotating shaft 570, extending along the centerline direction (an example of the direction of the rotation centerline). Furthermore, the temperature regulating unit 590 supplies a heat medium to one of the through holes 573 and discharges the heat medium from the other through holes 573. Thus, the temperature of the rotating shaft 570 can be adjusted throughout the entire region along the centerline direction.

[0117] Furthermore, the hole in the rotating shaft 570 supplying the heat medium is not limited to a hole that extends into the interior of the base end 571 like the through hole 573. For example, it could also be a hole formed where the heat medium folds back at the front end of the shaft portion 572.

[0118] The temperature regulating unit 590 supplies heat medium from the end of the movable pressure plate 120 side of one through hole 573 and discharges heat medium from the ends of the movable pressure plates 120 side of other through holes 573. Since the end of the rotary table 520 of the rotating shaft 570 on the disk portion 523 side is in contact with the rotary table 520, the heat medium can be supplied to the interior of the rotating shaft 570 with high precision by utilizing the openings at the ends of the movable pressure plates 120 side of the through holes 573, and can also be discharged from the interior of the rotating shaft 570.

[0119] The rotary table 520 and the rotary shaft 570 are configured such that the bottom surface 528 (an example of the first surface) of the rotary table 520 opposite to the rotary shaft 570 and the front surface 576 (an example of the second surface) of the rotary shaft 570 opposite to the rotary table 520 are in contact. Furthermore, a recess 575 is formed on the rotary shaft 570 that extends from the front surface 576, and the heat medium supplied to one through hole 573 moves through the recess 575 to another through hole 573. This allows for high-precision supply of the heat medium to the interior of the rotary shaft 570 and for it to be discharged from the interior of the rotary shaft 570.

[0120] Furthermore, it also includes a thermocouple 595 (an example of a temperature sensing unit) for detecting the temperature of the rotating shaft 570. The control device 500, which is part of the temperature regulating unit 590, controls the supply of the heat medium based on the temperature detected by the thermocouple 595. As a result, the temperature of the rotating shaft 570 can be regulated with high precision.

[0121] The injection molding machine 1 also includes: a rotary motor 531 that applies rotational driving force to the rotary table 520; and a torque detection unit (e.g., a current sensor that detects the current supplied to the rotary motor 531) that detects the torque of the rotary motor 531. Furthermore, a control device 500, which forms part of the temperature regulation unit 590, controls the supply of the heat medium based on the torque detected by the torque detection unit. Therefore, when it is necessary to reduce the temperature of the rotating shaft 570 (e.g., when the clearance between the inner and outer rings of the bearing 580 becomes smaller), the heat medium can be supplied with high precision.

[0122] Furthermore, in the injection molding machine 1 described above, the rotating shaft 570 is connected to the rotary table 520 by bolts 550, thereby transmitting the rotational force of the rotary table 520 to the rotating shaft 570. However, if the rotational force of the rotary table 520 is transmitted to the rotating shaft 570, the rotating shaft 570 and the rotary table 520 may not be connected. For example, the rotational force of the rotary table 520 may be transmitted to the rotating shaft 570 via a coupling installed in at least one of the rotary table 520 and the rotating shaft 570.

[0123] 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 rotary shaft 570.

[0124] <Second Implementation>

[0125] 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.

[0126] Figure 5 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.

[0127] like Figure 5 As shown, in the second embodiment, a plurality of recesses 529 are formed on the rotary table 520 that are recessed from the bottom surface 528 to the front side. Figure 5 (There are 2 in the middle). In this embodiment, a recess 529 is formed that connects the openings of two of the four through holes 573 formed on the rotating shaft 570 to each other, and a recess 529 that connects the openings of the remaining two through holes 573 to each other. Furthermore, the recess 529 is formed inside the plurality of through holes 543 at a different position than the portion where the through hole 543 through which the external thread of the bolt 550 passes is formed.

[0128] On the other hand, no recess 575 is formed on the rotating shaft 570 according to the second embodiment. That is, the front surface 576 is circular, and a plurality of (four in this embodiment) openings of through holes 573 and a plurality of (four in this embodiment) internal threads 574 are formed on the front surface 576.

[0129] In the injection molding machine 2 configured as described above, after the pump is driven to supply a hot medium through a supply pipe 591 into a through hole 573 of the rotating shaft 570, the hot medium passes through a recess 529 to other through holes 573, and is then discharged through a discharge pipe 592. Therefore, the injection molding machine 2 can regulate the temperature of the rotating shaft 570 throughout the entire region along its centerline. Consequently, according to the injection molding machine 2, variations in the clearance between the inner and outer rings of the bearing 580 can be suppressed.

[0130] <Third Implementation>

[0131] 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 temperature regulating unit 390 corresponds to the temperature regulating unit 590 and the rotation shaft 370 corresponds to the rotation shaft 570. 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.

[0132] Figure 6 This is an example of a partial cross-sectional view of the rotating shaft 370 and the temperature regulating unit 390 according to the third embodiment.

[0133] like Figure 6 As shown, the rotating shaft 370 according to the third embodiment differs from the rotating shaft 570 according to the first embodiment in that it does not have a through hole 573, but has an insertion hole 373. The insertion hole 373 extends from the rear side to the front along the center line direction and inserts the heater 340. The insertion hole 373 is formed in the center of the entire area of ​​the shaft portion 572.

[0134] The temperature regulating unit 390 includes a heater 340. An example is given where the heater 340 is a cylindrical heater. For instance, the heater 340 includes: a nichrome wire (not shown) arranged in a spiral shape inside a cylindrical metal tube 341, with a ceramic core (not shown) as its main axis; and a lead wire 342 having insulating powder (in other words, magnesium oxide) (not shown) and exposed on the outside of the metal tube 341. The lead wire 342 passes through a connecting hole 126h formed in the movable pressure plate 120 and connects to the current supply unit, which will be described later.

[0135] The control device 500, which forms part of the temperature regulation unit 390, includes a current supply unit (e.g., a transistor) that supplies current to the heater 340, and controls the power supply to the heater 340 by activating the current supply unit.

[0136] Furthermore, the control device 500 controls the energization of the heater 340 based on the temperature of the rotating shaft 370 detected by the thermocouple 595. For example, the control device 500 energizes the heater 340 when the temperature of the rotating shaft 370 detected by the thermocouple 595 is below a preset temperature, and stops energizing the heater 340 when the temperature exceeds the preset temperature.

[0137] For example, in a cold state, if current is supplied to heater 340 when the temperature of rotating shaft 370 is below a specified temperature, heater 340 heats up, and rotating shaft 370 is heated. As a result, the inner ring of bearing 580 is heated, and the gap between the inner and outer rings of bearing 580 decreases. Consequently, for example, even in a cold state, it is possible to suppress the deterioration of the rotational accuracy of rotary table 520.

[0138] Furthermore, as described above, in the injection molding machine 3, even in a cold state, the increase in the gap between the inner and outer rings of the bearing 580 can be suppressed. Therefore, compared to a structure without the temperature regulating unit 390, the gap between the inner and outer rings at room temperature can be set to be larger. As a result, for example, even without the temperature regulating unit 590 as described in the first embodiment, the desired gap between the inner and outer rings can be ensured even when thermal expansion occurs in the inner ring of the bearing 580.

[0139] Alternatively, the temperature control unit 390 according to the third embodiment can be applied to the injection molding machine 1 according to the first embodiment or the injection molding machine 2 according to the second embodiment. For example, in the injection molding machine 1 according to the first embodiment, an insertion hole 373 is formed on the rotating shaft 570 to insert a heater 340, and when the temperature of the rotating shaft 570 is below a predetermined temperature, the control device 500 energizes the heater 340. This allows for more precise suppression of changes in the clearance between the inner and outer rings of the bearing 580.

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 is configured to protrude toward the side of the retaining member opposite to the side that holds the second mold, so as to transmit the rotational force of the retaining member, or to transmit the rotational force to the retaining member; A support member, rotatably supporting the retaining member via a bearing embedded in the rotating shaft; and Temperature regulating unit, used to regulate the temperature of the rotating shaft.

2. The injection molding machine according to claim 1, wherein, The temperature regulating unit supplies heat medium to the hole formed inside the rotating shaft.

3. The injection molding machine according to claim 2, wherein, Multiple through holes are formed inside the rotating shaft, extending along the direction of the rotation center line. The temperature regulating unit supplies the heat medium to one of the plurality of through holes and discharges the heat medium from the other through holes.

4. The injection molding machine according to claim 3, wherein, The temperature regulating unit supplies the heat medium from the end of the support member side of one of the through holes, and discharges the heat medium from the end of the support member side of the other through holes.

5. The injection molding machine according to claim 4, wherein, 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 that is recessed from the second surface is formed on the rotating shaft, or a recess that is recessed from the first surface is formed on the retaining member. The heat medium supplied to one of the through holes moves through the recess to the other through holes.

6. The injection molding machine according to any one of claims 2 to 5, further comprising a temperature detection unit for detecting the temperature of the rotating shaft. The temperature regulating unit controls the supply of the heat medium based on the temperature detected by the temperature detection unit.

7. The injection molding machine according to claim 6, further comprising: The motor applies a rotational driving force to the holding member; and The torque detection unit detects the torque of the motor. The temperature regulating unit controls the supply of the heat medium based on the torque detected by the torque detection unit.

8. The injection molding machine according to claim 1, wherein, The temperature regulating unit has a heater disposed inside the rotating shaft.

9. The injection molding machine according to claim 8, further comprising a temperature detection unit for detecting the temperature of the rotating shaft. The temperature regulating unit controls the power supply to the heater based on the temperature detected by the temperature detection unit.

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