Material discharge device and injection molding device

Abstract

To improve durability of an injection control part for injection of a plasticized material at a predetermined pressure to the outside.SOLUTION: A material discharge device includes a cylinder connected to a channel through which a plasticization material flows, a plunger reciprocating in the cylinder, a ball screw configured so as to detach the plunger on one end, a nut connecting with the ball screw, and a suction delivery part having a motor that drives the plunger via the ball screw, wherein the motor has a rotor and a stator arranged opposite to the rotor, either one of the rotor and the stator has a magnet, either one of the rotor and the stator is connected with an outer peripheral surface of the nut, and the rotor rotates in a state of having a spacing to the stator by a magnetic force of the magnet.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a material discharge device and an injection molding device.

Background Art

[0002] A material discharge device having a plunger is known. The injection molding device described in Patent Document 1 includes an injection control unit which is an example of a material discharge device. The injection molding device injects a plasticized material using the injection control unit. The injection control unit includes a cylinder, a plunger, and a plunger drive unit. The injection control unit executes a metering operation and an injection operation by sliding the plunger within the cylinder. The plunger is driven by a plunger drive unit constituted by a motor and gears.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the injection control unit injects the plasticized material to the outside at a predetermined pressure, improvement in durability is required.

Means for Solving the Problems

[0005] The material discharge device of the present disclosure includes a plasticizing unit that plasticizes a material to generate a plasticized material, a nozzle having a nozzle opening that sends out the plasticized material to the outside from the nozzle opening, a cylinder communicating with the nozzle opening and connected to a flow path through which the plasticized material flows, a plunger that reciprocates within the cylinder, a ball screw configured to be attachable to the plunger at one end, a nut connected to the ball screw, and a suction and discharge unit having a motor that drives the plunger via the ball screw, and a control unit. The control unit causes the suction and discharge unit to perform a suction operation of sucking the plasticized material into the cylinder by moving the plunger in a direction away from the flow path, and a discharge operation of discharging the plasticized material in the cylinder to the flow path by moving the plunger in a direction approaching the flow path. The motor has a rotor and a stator disposed opposite to the rotor. Either the rotor or the stator has a magnet. Either the rotor or the stator is connected to the outer peripheral surface of the nut. The rotor rotates at a distance from the stator by the magnetic force of the magnet.

[0006] The injection molding device of the present disclosure includes the above-described material discharge device, and the nozzle discharges the plasticized material toward a mold.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0008] FIG. 1 is a side view schematically showing an injection molding apparatus 100. The injection molding apparatus 100 shown in FIG. 1 includes a material supply unit 10, an injection unit 20, a mold unit 30, a mold clamping unit 40, and a control device 50.

[0009] A plurality of figures including FIG. 1 show an X-axis, a Y-axis, and a Z-axis as three axes orthogonal to each other. The X-axis is an axis parallel to the installation surface of the injection molding apparatus 100. The +X direction is the direction from the front to the back of the injection molding apparatus 100 shown in FIG. 1. The -X direction is the direction from the back to the front of the injection molding apparatus 100 shown in FIG. 1. The Y-axis is an axis parallel to the installation surface of the injection molding apparatus 100 and perpendicular to the X-axis. The +Y direction is the direction from the injection unit 20 to the mold unit 30 of the injection molding apparatus 100 shown in FIG. 1. The -Y direction is the direction from the mold unit 30 to the injection unit 20 of the injection molding apparatus 100 shown in FIG. 1. The Z-axis is an axis perpendicular to the installation surface of the injection molding apparatus 100. The +Z direction is the direction upward from the installation surface. The -Z direction is the vertical direction downward from the installation surface.

[0010] The material supply unit 10 supplies a material that becomes a raw material to the injection unit 20. The material supply unit 10 is constituted by, for example, a hopper. The shape of the material supplied from the material supply unit 10 is pellet-shaped or powder-shaped. The material supplied by the material supply unit 10 is an ABS (acrylonitrile butadiene styrene) resin or the like.

[0011] The injection unit 20 plasticizes the material supplied from the material supply unit 10 to make a plasticized material. The injection unit 20 injects the plasticized material toward the mold unit 30. The injection unit 20 corresponds to an example of a material discharge device.

[0012] Plasticization is a concept that includes melting and refers to changing from a solid state to a state with fluidity. In the case of a material where glass transition occurs, plasticization means raising the temperature of the material above the glass transition point. In the case of a material where glass transition does not occur, plasticization means raising the temperature of the material above the melting point.

[0013] In the mold part 30, a cavity 34 corresponding to the shape of the molded product is formed. The cavity 34 will be described later. The plasticized material injected from the injection part 20 flows into the cavity 34. The plasticized material is cooled within the cavity 34. The plasticized material is solidified by cooling. When the plasticized material is solidified, the molded product is produced.

[0014] The mold clamping part 40 opens and closes the mold part 30. After the plasticized material is solidified, the mold clamping part 40 opens the mold part 30. When the mold clamping part 40 opens the mold part 30, the molded product is discharged to the outside.

[0015] The control device 50 is composed of, for example, a computer having a processor, a storage device, and an input / output interface for inputting and outputting signals to and from the outside. The control device 50 executes various functions by the processor executing a program stored in the storage device. The control device 50 controls the injection part 20 and the mold clamping part 40. The control device 50 may be composed of a combination of a plurality of circuits instead of a computer.

[0016] Figure 2 is a cross-sectional view schematically showing the injection molding apparatus 100. Figure 2 is a cross-sectional view taken along line I-I in Figure 1. The injection part 20 shown in Figure 2 has a plasticizing part 60, a suction and delivery part 70, and a nozzle 80.

[0017] The plasticizing unit 60 plasticizes at least a part of the material supplied from the material supply unit 10. By plasticizing the material, the plasticizing unit 60 generates a paste-like plasticized material having fluidity. The plasticizing unit 60 is configured to guide the plasticized material to the suction and delivery unit 70. The plasticizing unit 60 includes a screw case 62, a drive motor 64, a flat screw 110, a barrel 120, and a barrel heater 130.

[0018] The screw case 62 is a housing that houses the flat screw 110. The flat screw 110 is housed in a space surrounded by the screw case 62 and the barrel 120.

[0019] The drive motor 64 is connected to the screw case 62. The drive motor 64 rotates the flat screw 110. The drive motor 64 is, for example, a servo motor. The shaft 66 of the drive motor 64 is connected to the flat screw 110. The drive motor 64 is controlled by the control device 50.

[0020] The flat screw 110 is configured in a substantially cylindrical shape in which the length along the rotation axis R is smaller than the width in the direction orthogonal to the rotation axis R. The rotation axis R is an axis parallel or substantially parallel to the Y axis. The flat screw 110 rotates about the rotation axis R by the torque generated by the drive motor 64. The flat screw 110 has a shaft surface 111, a groove forming surface 112, and a connection surface 113. The shaft 66 is connected to the shaft surface 111. The groove forming surface 112 is a surface opposite to the shaft surface 111. The connection surface 113 connects the shaft surface 111 and the groove forming surface 112.

[0021] FIG. 3 is a perspective view schematically showing the flat screw 110. FIG. 3 shows the flat screw 110 shown in FIG. 2 in a state where the positional relationship along the Y axis is reversed.

[0022] On the groove forming surface 112 of the flat screw 110, a first groove 114 is formed. The first groove 114 has a screw central portion 115, a connecting portion 116, and a material introduction portion 117. The screw central portion 115 faces a communication hole 126 formed in the barrel 120. The communication hole 126 will be described later. The screw central portion 115 communicates with the communication hole 126. The connecting portion 116 connects the screw central portion 115 and the material introduction portion 117. The connecting portion 116 is formed in a spiral shape from the screw central portion 115 toward the outer periphery of the groove forming surface 112. The material introduction portion 117 is formed on the outer periphery of the groove forming surface 112. The material introduction portion 117 is formed on the connection surface 113 of the flat screw 110. The material supplied from the material supply unit 10 is introduced into the first groove 114 from the material introduction portion 117. The material introduced into the first groove 114 is conveyed to the communication hole 126 through the connecting portion 116 and the screw central portion 115. Two first grooves 114 are formed on the groove forming surface 112 shown in FIG. 3.

[0023] The number of the first grooves 114 formed on the groove forming surface 112 is not limited to two. Three first grooves 114 may be formed on the groove forming surface 112, or one first groove 114 may be formed.

[0024] The plasticizing unit 60 may have a long in-line screw having spiral grooves on its side surface instead of the flat screw 110. The plasticizing unit 60 plasticizes the material by the rotation of the in-line screw.

[0025] The barrel 120 shown in FIG. 2 is provided to face the flat screw 110. The barrel 120 has a facing surface 122 that faces the groove forming surface 112 of the flat screw 110. The facing surface 122 faces the groove forming surface 112 along the Y axis. A communication hole 126 is formed at the center of the facing surface 122.

[0026] FIG. 4 is a diagram schematically showing the barrel 120. FIG. 4 shows a surface including the facing surface 122 of the barrel 120.

[0027] On the opposing surface 122 of the barrel 120, a plurality of second grooves 124 and communication holes 126 are formed. Six second grooves 124 are formed on the opposing surface 122 shown in FIG. 4, but the number is not particularly limited. The plurality of second grooves 124 are formed around the communication hole 126 in a plan view from the -Y direction. One end of the second groove 124 is connected to the communication hole 126. The second groove 124 is formed in a spiral shape from the communication hole 126 toward the outer periphery of the opposing surface 122. The second groove 124 has a function of guiding the plasticized material to the communication hole 126. The communication hole 126 allows the plasticized material to flow out in the +Y direction of the barrel 120.

[0028] The shape of the second groove 124 is not particularly limited. The second groove 124 may be linear. One end of the second groove 124 does not have to be connected to the communication hole 126. The second groove 124 does not have to be formed on the opposing surface 122. Preferably, the second groove 124 is formed on the opposing surface 122. When the second groove 124 is formed on the opposing surface 122, the plasticized material is efficiently guided to the communication hole 126.

[0029] The barrel heater 130 shown in FIG. 2 is provided on the barrel 120. The barrel heater 130 heats the material supplied between the flat screw 110 and the barrel 120. The barrel heater 130 heats the material supplied to the first groove 114. The barrel heater 130 is controlled by the control device 50. The plasticizing unit 60 heats the material while conveying it toward the communication hole 126 by the flat screw 110, the barrel 120, and the barrel heater 130. The plasticizing unit 60 generates a plasticized material by heating the material. The plasticizing unit 60 causes the generated plasticized material to flow out from the communication hole 126 to the suction and delivery unit 70.

[0030] The suction and delivery unit 70 includes a cylinder 73 and a plunger 78. The suction and delivery unit 70 guides the plasticized material located at the communication hole 126 into the cylinder 73 by moving the plunger 78 in the -X direction away from the communication hole 126. The suction and delivery unit 70 measures the plasticized material within the cylinder 73. The suction and delivery unit 70 injects the plasticized material within the cylinder 73 into the mold part 30 via the nozzle 80 by moving the plunger 78 in the +X direction approaching the communication hole 126. Details of the suction and delivery unit 70 will be described later. FIG. 2 shows the suction and delivery unit 70 in a simplified manner.

[0031] The nozzle 80 is formed with a nozzle hole 82. The nozzle hole 82 communicates with the communication hole 126. The nozzle hole 82 has a nozzle opening 84 through which the plasticized material is injected. The nozzle 80 sends out the plasticized material supplied from the plasticizing unit 60 to the outside through the nozzle opening 84. The plasticized material measured within the cylinder 73 is sent from the suction and delivery unit 70 through the communication hole 126 to the nozzle hole 82. The plasticized material is injected from the nozzle opening 84 of the nozzle hole 82 into the mold part 30.

[0032] The nozzle hole 82 and the communication hole 126 constitute a flow path 140 through which the plasticized material flows. The longitudinal direction of the flow path 140 is along the Y-axis direction. The cylinder 73 is connected to the flow path 140. The cylinder 73 is arranged along the X-axis.

[0033] The nozzle 80 has an opening and closing mechanism 86 for opening and closing the nozzle opening 84. The opening and closing mechanism 86 opens the nozzle opening 84 when the pressure of the plasticized material within the flow path 140 is greater than a predetermined pressure. The opening and closing mechanism 86 is constituted by a valve or the like.

[0034] The mold part 30 has a molding die 32. The molding die 32 is a mold. The plasticized material sent to the nozzle hole 82 is injected from the nozzle opening 84 into the cavity 34 of the molding die 32. The molding die 32 is injected with the plasticized material sent from a nozzle 80 having a nozzle hole 82 and a nozzle opening 84. The molding die 32 has a movable die 36 and a fixed die 38 facing each other. The cavity 34 is formed between the movable die 36 and the fixed die 38. The cavity 34 is a space corresponding to the shape of the molded product. The movable die 36 and the fixed die 38 are made of metal. The materials of the movable die 36 and the fixed die 38 may be made of ceramic or resin.

[0035] The mold clamping part 40 has a mold driving part 42 and a mold clamping ball screw part 44. The mold driving part 42 is composed of a mold clamping drive motor, gears, etc. The mold driving part 42 is connected to the movable die 36 via the mold clamping ball screw part 44. The mold driving part 42 is controlled by a control device 50. The mold clamping ball screw part 44 transmits the power generated by the drive of the mold driving part 42 to the movable die 36. The mold clamping part 40 moves the movable die 36 by the mold driving part 42 and the mold clamping ball screw part 44. The mold clamping part 40 opens and closes the mold part 30 by moving the movable die 36.

[0036] The control device 50 controls each part of the injection molding device 100. The control device 50 has a storage part 52, a display part 54, and a control part 56.

[0037] The storage part 52 stores programs, data, etc. for causing the control part 56 to execute various calculation processes and control processes. The storage part 52 may be used as a working area for the control part 56. The storage part 52 is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), etc.

[0038] The display unit 54 displays various images according to instructions from the control unit 56. The display unit 54 is composed of an LCD (Liquid Crystal Display), an organic EL (Electroluminescence) display, an EPD (Electrophoretic Display), a touch panel type display, and the like.

[0039] The control unit 56 performs various calculation processes and control processes according to the program stored in the storage unit 52. The control unit 56 is a processor including, for example, any one of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), and an ASIC (Application Specific Integrated Circuit). The control unit 56 is composed of one or more processors. The control unit 56 controls the operations of the injection unit 20, the mold unit 30, the mold clamping unit 40, and the like.

[0040] FIG. 5 shows a schematic configuration of the suction and delivery unit 70. FIG. 5 shows the suction and delivery unit 70 and a barrel 120 connected to a cylinder 73. FIG. 5 is a cross-sectional view taken along line II-II in FIG. 2. The suction and delivery unit 70 includes a cylinder 73, a plunger 78, a motor 150, a ball screw 157, and a nut 159.

[0041] The cylinder 73 is connected to a flow path 140 through which the plasticized material flows. The cylinder 73 communicates with a nozzle opening 84. The cylinder 73 extends in the -X direction from the flow path 140. The cylinder 73 is composed of a hollow cylindrical member.

[0042] The plunger 78 reciprocates within the cylinder 73. The plunger 78 shown in FIG. 5 moves in the +X direction and the -X direction along the X axis. The +X direction is the direction in which the plunger 78 approaches the flow path 140. The -X direction is the direction in which the plunger 78 moves away from the flow path 140. The plunger 78 is a rod-shaped member extending along the X axis.

[0043] The motor 150 drives the ball screw 157 or the nut 159. The motor 150 drives the plunger 78 via the ball screw 157. The motor 150 is controlled by the control unit 56. The motor 150 has a motor housing 151, a stator 153, and a rotor 155.

[0044] The motor housing 151 houses the stator 153 and the rotor 155. The motor housing 151 supports the stator 153. The motor housing 151 houses a part of the ball screw 157. The motor housing 151 houses at least a part of the nut 159. The motor housing 151 shown in FIG. 5 houses the entire nut 159. By the motor housing 151 housing a part of the ball screw 157 and at least a part of the nut 159, it becomes possible to shorten the length of the suction and delivery unit 70 along the X-axis.

[0045] The stator 153 generates a magnetic field that rotates the rotor 155. The stator 153 is supported by the motor housing 151. The stator 153 is disposed on the outer periphery of the rotor 155, the ball screw 157, and the nut 159. The stator 153 is disposed to face the rotor 155. A winding 165 is wound around the stator 153.

[0046] The rotor 155 rotates by the magnetic field generated by the stator 153. The rotor 155 is disposed on the inner peripheral portion of the stator 153. The rotor 155 rotates while being spaced apart from the stator 153. The rotor 155 shown in FIG. 5 is connected to the outer peripheral surface of the nut 159 and supports the nut 159. The rotor 155 moves the ball screw 157 in the +X direction and the -X direction by rotating the nut 159.

[0047] FIG. 6 is a diagram schematically showing the winding arrangement of the motor 150. FIG. 6 is a cross-sectional view taken along line III-III shown in FIG. 5. The winding arrangement shown in FIG. 6 is an example, and the number of slots 163 of the stator 153 and the number of poles of the rotor 155 can be appropriately changed.

[0048] The motor 150 shown in Fig. 6 has a 9-slot 6-pole structure. A winding 165 that serves both functions of torque generation and support force generation is wound in the slot 163. The motor 150 shown in Fig. 6 is a bearingless motor that uses a single type of winding 165 to generate an axial support force in addition to the rotational torque.

[0049] The motor 150 uses a d-q rotating coordinate system that rotates synchronously with the rotor 155. With respect to the virtual central axis VS, torque is generated by the q-axis component of the current, and an axial support force is generated by the d-axis component of the current. Here, the axis in the direction in which the magnetic flux of the magnet 167 passes from the center of the rotor 155 toward the outside is the d-axis, and the axis in the direction passing between the poles of the magnet 167 is the q-axis. The stator 153 is divided into a first section α, a second section β, and a third section γ. The first section α has a first U-phase winding N U1 , a first V-phase winding N V1 , and a first W-phase winding N W1 wound therein. The second section β has a second U-phase winding N U2 , a second V-phase winding N V2 , and a second W-phase winding N W2 wound therein. The third section γ has a third U-phase winding N U3 , a third V-phase winding N V3 , and a third W-phase winding N W3 wound therein. The rotor 155 is a cylindrical core. On the surface of the rotor 155, six-pole magnets 167 are attached in a ring shape with alternating polarities in the circumferential direction.

[0050] The torque generation principle of the motor 150 is the same as that of a conventional motor. Rotational torque is generated by controlling the q-axis current of the winding 165. By controlling the d-axis current of the winding 165, an axial support force of a predetermined magnitude and direction is generated. The axial support force is generated in a certain direction by controlling the d-axis currents of the first section α, the second section β, and the third section γ to make the gap magnetic flux density unbalanced. By controlling the magnitude of the d-axis current, the gripping force on the rotor 155 is adjusted.

[0051] The motor 150 supports the rotor 155 at a distance from the stator 153 by the magnetic force of the winding 165 and the magnet 167. Since the rotor 155 is supported by the magnetic force, the bearings for supporting the rotor 155 can be reduced. The motor 150 does not have bearings. The rotor 155 is not supported by bearings. By not having bearings, the durability of the motor 150 is improved. The motor 150 can stabilize the rotation of the rotor 155 because there is no rotational resistance due to bearings. The suction and delivery unit 70 having the motor 150 can reduce the variation in metering accuracy.

[0052] The motor 150 shown in FIG. 6 is composed of a rotor 155 having a magnet 167 and a stator 153 around which a winding 165 is wound, but is not limited thereto. The motor 150 may be composed of a rotor 155 around which a winding 165 is wound and a stator 153 having a magnet 167. Either the rotor 155 or the stator 153 has a magnet 167.

[0053] The ball screw 157 shown in FIG. 5 moves in the +X direction and the -X direction by the rotation of the rotor 155. One end of the ball screw 157 is configured to be able to attach the plunger 78. The +X direction end of the ball screw 157 is configured to be able to attach the plunger 78 directly or via another member. The ball screw 157 shown in FIG. 5 is attached to the plunger 78 via the joining member 161. The other end of the ball screw 157 is fixedly supported by the motor housing 151. The -X direction end of the ball screw 157 is non-rotatably supported by the motor housing 151.

[0054] When the ball screw 157 moves in the +X direction, the plunger 78 moves in the +X direction. When the ball screw 157 moves in the -X direction, the plunger 78 moves in the -X direction. The motor 150 moves the plunger 78 via the ball screw 157. The ball screw 157 is supported in a non-rotatable manner. When the ball screw 157 moves along the X-axis, the ball screw 157 does not rotate. The ball screw 157 applies a force to the plunger 78 to move the plunger 78 along the X-axis and does not transmit a force to rotate the plunger 78. The plunger 78 moves along the X-axis without rotating. Since the plunger 78 does not rotate, it is difficult for the plasticized material to enter between the outer peripheral surface of the plunger 78 and the inner peripheral surface of the cylinder 73. The movement of the plunger 78 along the X-axis is stabilized.

[0055] The nut 159 fits onto the ball screw 157. The outer peripheral surface of the nut 159 is connected to the rotor 155. The nut 159 shown in FIG. 5 is supported by the rotor 155. The nut 159 rotates when the rotor 155 rotates. When the nut 159 rotates, the ball screw 157 moves along the X-axis. The motor 150 moves the ball screw 157 along the X-axis by rotating the nut 159.

[0056] The outer peripheral surface of the nut 159 is supported by the rotor 155. Since the outer peripheral surface of the nut 159 is supported by the rotor 155, in a plan view from a plane perpendicular to the X-axis, the rotor 155 and the nut 159 are arranged overlapping each other. Since the outer peripheral surface of the nut 159 is supported by the rotor 155, the length of the suction and delivery unit 70 along the X-axis is shortened.

[0057] The joining member 161 joins the ball screw 157 and the plunger 78. The joining member 161 joins the plunger 78 to the ball screw 157 in an attachable and detachable manner. Since the joining member 161 detachably joins the plunger 78 to the ball screw 157, the plunger 78 can be replaced.

[0058] The joint member 161 functions as a heat insulating member. The joint member 161 suppresses the transfer of the heat of the plunger 78 heated in the barrel 120 to the motor 150. The joint member 161 can reduce the transfer of the influence of the heat of the barrel 120 to the motor 150. A part of the ball screw 157 and the plunger 78 may be joined with a gap therebetween. When the ball screw 157 and the plunger 78 are joined with a gap therebetween, the transfer of the heat of the plunger 78 to the motor 150 is suppressed.

[0059] A part of the ball screw 157 shown in FIG. 5 is disposed between the motor 150 and the barrel 120. A space is formed on the outer peripheral portion of the ball screw 157 between the motor 150 and the barrel 120. The motor 150 and the barrel 120 are spaced apart from each other with the space therebetween along the X-axis. By disposing the motor 150 and the barrel 120 to be spaced apart from each other with the space therebetween along the X-axis, the transfer of the heat of the barrel 120 to the motor 150 can be suppressed. A heat insulating material may be disposed between the motor 150 and the barrel 120.

[0060] The motor 150 shown in FIG. 5 supports the nut 159 with the rotor 155, but is not limited thereto. The motor 150 may support the ball screw 157 with the rotor 155. The nut 159 is supported by the motor housing 151. The ball screw 157 moves along the X-axis by the rotation of the rotor 155. The ball screw 157 moves along the X-axis while rotating by the rotation of the rotor 155. The plunger 78 receives the rotational force of the ball screw 157. The plunger 78 rotates by the rotational force. The plunger 78 moves along the X-axis while rotating. It is preferable that the motor 150 supports the nut 159 with the rotor 155.

[0061] The motor 150 is driven by the control unit 56. By controlling the motor 150, the control unit 56 moves the plunger 78 along the X-axis via the ball screw 157. The control unit 56 executes a suction operation of sucking the plasticized material into the cylinder 73 by moving the plunger 78 in the -X direction. The control unit 56 executes a delivery operation of delivering the plasticized material to the flow path 140 by moving the plunger 78 in the +X direction. The suction and delivery unit 70 executes the suction operation and the delivery operation under the control of the control unit 56.

[0062] The injection unit 20 includes a plasticizing unit 60 that plasticizes the material to generate a plasticized material, a nozzle 80 having a nozzle opening 84 that delivers the plasticized material to the outside from the nozzle opening 84, a cylinder 73 that communicates with the nozzle opening 84 and is connected to a flow path 140 through which the plasticized material flows, a plunger 78 that reciprocates within the cylinder 73, a ball screw 157 configured to be attachable to one end of the plunger 78, a nut 159 connected to the ball screw 157, a suction and delivery unit 70 having a motor 150 that drives the plunger 78 via the ball screw 157, and a control unit 56. The control unit 56 causes the suction and delivery unit 70 to execute a suction operation of sucking the plasticized material into the cylinder 73 by moving the plunger 78 in the -X direction away from the flow path 140, and a delivery operation of delivering the plasticized material in the cylinder 73 to the flow path 140 by moving the plunger 78 in the +X direction closer to the flow path 140. The motor 150 has a rotor 155 and a stator 153 disposed opposite to the rotor 155. Either the rotor 155 or the stator 153 has a magnet 167. Either the rotor 155 or the stator 153 is connected to the outer peripheral surface of the nut 159. The rotor 155 rotates at a distance from the stator 153 by the magnetic force of the magnet 167. The motor 150 is composed of a bearingless motor that does not have bearings. The motor 150 is less likely to deteriorate due to mechanical sliding. The motor 150 can improve the durability of the injection unit 20 that injects the plasticized material at a predetermined pressure.

[0063] The rotor 155 supports the nut 159. The motor 150 preferably moves the plunger 78 by rotating the nut 159 supported by the rotor 155. When the plunger 78 is driven by the rotation of the nut 159, it can be moved along the X-axis without rotating the plunger 78. It becomes difficult for the plasticized material to penetrate between the outer peripheral surface of the plunger 78 and the inner peripheral surface of the cylinder 73. An increase in the sliding resistance of the plunger 78 due to the penetration of the plasticized material is suppressed.

[0064] The ball screw 157 is preferably connected to the plunger 78 through the joining member 161 or a gap. The heat of the plunger 78 is less likely to be transmitted to the motor 150, and the influence of the heat of the barrel 120 on the motor 150 is suppressed.

[0065] The injection molding apparatus 100 includes a plasticizing unit 60 that plasticizes a material to generate a plasticized material, a nozzle 80 having a nozzle opening 84 that sends the plasticized material to the outside from the nozzle opening 84, a cylinder 73 communicating with the nozzle opening 84 and connected to a flow path 140 through which the plasticized material flows, a plunger 78 that reciprocates within the cylinder 73, a ball screw 157 configured to be attachable to one end of the plunger 78, a nut 159 connected to the ball screw 157, and a suction and delivery unit 70 having a motor 150 that drives the plunger 78 via the ball screw 157, a mold unit 30 having a mold 32 into which the plasticized material sent from the nozzle 80 is injected, and a control unit 56. The control unit 56 causes the suction and delivery unit 70 to perform a suction operation of sucking the plasticized material into the cylinder 73 by moving the plunger 78 in the -X direction away from the flow path 140, and a delivery operation of sending the plasticized material in the cylinder 73 to the flow path 140 by moving the plunger 78 in a direction approaching the flow path 140. The motor 150 includes a rotor 155 and a stator 153 disposed opposite to the rotor 155. Either the rotor 155 or the stator 153 has a magnet 167. Either the rotor 155 or the stator 153 is connected to the outer peripheral surface of the nut 159. The rotor 155 rotates at a distance from the stator 153 by the magnetic force of the magnet 167. The motor 150 is composed of a bearingless motor that does not have bearings. The motor 150 is less likely to deteriorate due to mechanical sliding. The motor 150 can improve the durability of the injection molding apparatus 100 that injects the plasticized material at a predetermined pressure.

[0066] In the injection molding apparatus 100 shown in FIG. 2, a bearingless motor is used as the motor 150, but it is not limited thereto. A bearingless motor may be used for at least one of the drive motor 64 and the mold clamping drive motor of the mold drive unit 42. When a bearingless motor is used for the mold clamping drive motor of the mold drive unit 42, the mold clamping ball screw portion 44 functions in the same manner as the ball screw 157.

[0067] Figure 7 shows a schematic configuration of the cylinder 73. The cylinder 73 includes an inner cylinder 171, an outer cylinder 173, and a cylinder heater 175.

[0068] The inner cylinder 171 is a cylindrical member having a predetermined inner diameter. The inner cylinder 171 has a predetermined axial length along the X-axis. The inner cylinder 171 defines the inner diameter of the cylinder 73.

[0069] The outer cylinder 173 is a cylindrical member. The axial length of the outer cylinder 173 along the X-axis is equal to or substantially equal to the axial length of the inner cylinder 171 along the X-axis. The outer cylinder 173 is press-fitted onto the outer periphery of the inner cylinder 171. When the outer cylinder 173 is press-fitted onto the inner cylinder 171, the strength of the cylinder 73 against the internal pressure increases. When the outer cylinder 173 is press-fitted onto the inner cylinder 171, the outer cylinder 173 makes the inner cylinder 171 detachable.

[0070] The outer cylinder 173 is configured to be press-fittable with a second inner cylinder having a second inner diameter different from the inner diameter of the inner cylinder 171 shown in Figure 7. The outer cylinder 173 can exchange the inner cylinder 171 and the second inner cylinder. By replacing the inner cylinder 171 with the second inner cylinder, the amount of the plasticized material injected into the cylinder 73 can be changed.

[0071] The cylinder heater 175 is disposed between the inner cylinder 171 and the outer cylinder 173. By disposing the cylinder heater 175 between the inner cylinder 171 and the outer cylinder 173, the power efficiency when heating the cylinder 73 is improved. The cylinder heater 175 is disposed, for example, in a groove formed on the outer periphery of the inner cylinder 171. By disposing the cylinder heater 175 in the groove, the outer cylinder 173 is more easily press-fitted onto the inner cylinder 171.

[0072] The cylinder heater 175 heats the entire length of the cylinder 73 along the X-axis. The cylinder heater 175 is preferably in the form of a heater wound around the outer periphery of the inner cylinder 171. The cylinder heater 175 is preferably, as an example, a coil heater wound around the inner cylinder 171. The coil heater can adjust the temperature distribution along the X-axis of the cylinder 73 according to the winding method around the inner cylinder 171.

[0073] FIG. 8 shows a schematic configuration of the cylinder heater 175. FIG. 8 shows an example of the winding method of the cylinder heater 175. The cylinder 73 is, as an example, divided into a first region R1, a second region R2, and a third region R3 in order from the -X direction along the X-axis.

[0074] The first region R1 is an end region of the cylinder 73 in the -X direction. The first region R1 is located on the outer peripheral portion of the barrel 120. The first region R1 is a region that is easily cooled by the outside air. In the first region R1, the coil heater is wound with the second number of turns.

[0075] The second region R2 is a central region of the cylinder 73. The second region R2 is located inside the barrel 120 and is a region that easily stores heat. In the second region R2, the coil heater is wound with the first number of turns. The first number of turns is less than the second number of turns.

[0076] The third region R3 is a region of the cylinder 73 in the +X direction. The third region R3 is located in the vicinity of the flow path 140 and is a region where heat is easily taken away by the plasticized material. In the third region R3, the coil heater is, as an example, wound with the second number of turns.

[0077] The first region R1 and the third region R3 correspond to both ends of the cylinder 73. The first number of turns of the coil heater in the second region R2, which is the central part of the cylinder 73, is less than the second number of turns of the coil heater in the first region R1 and the third region R3, which are both ends of the cylinder 73. By the first number of turns being less than the second number of turns, the temperature distribution along the X-axis of the cylinder 73 is set within a predetermined temperature range. The temperature of the plasticized material sucked into the cylinder 73 is likely to be maintained within the predetermined temperature range.

[0078] In the third region R3, the coil heater may be wound with a third number of turns different from the second number of turns. The third number of turns is more than the first number of turns. The second number of turns and the third number of turns are appropriately set according to heat absorption by the outside air and heat absorption by the plasticizing member. The lengths of the first region R1, the second region R2, and the third region R3 along the X-axis are appropriately set according to the temperature distribution of the barrel 120.

[0079] The cylinder 73 preferably has an inner cylinder 171 that defines the inner diameter, an outer cylinder 173 press-fitted on the outer periphery of the inner cylinder 171, and a cylinder heater 175 disposed between the inner cylinder 171 and the outer cylinder 173. Since the cylinder 73 is composed of the inner cylinder 171 and the outer cylinder 173 press-fitted on the outer periphery of the inner cylinder 171, the strength against the internal pressure of the cylinder 73 increases. Since the cylinder heater 175 is disposed between the inner cylinder 171 and the outer cylinder 173, the power efficiency when the cylinder 73 is heated is improved.

[0080] The outer cylinder 173 is preferably configured to be press-fittable to a second inner cylinder having a second inner diameter different from the inner diameter of the inner cylinder 171. By using the outer cylinder 173 as a common member, it becomes possible to change the suction amount of the plasticized material.

[0081] The cylinder heater 175 is a coil heater wound around the inner cylinder 171. It is preferable that the first winding number of the coil heater at the central part of the cylinder 73 is less than the second winding number of the coil heater at both ends of the cylinder 73. Since the first winding number is smaller than the second winding number, the temperature distribution along the X-axis of the cylinder 73 is set within a predetermined temperature range. The temperature of the plasticized material sucked into the cylinder 73 is likely to be maintained within the predetermined temperature range.

[0082] FIG. 9 shows a schematic configuration of the three-dimensional shaping apparatus 200. The three-dimensional shaping apparatus 200 includes an injection unit 20 which is a material discharge device, a shaping stage 210, a moving mechanism 220, and a control device 50. The three-dimensional shaping apparatus 200 is an example of an apparatus including a material discharge device. The injection unit 20 shown in FIG. 9 has the same configuration as the injection unit 20 shown in FIG. 2 except for a valve 230 described later. In FIG. 9, the same components as those included in FIG. 2 are given the same reference numerals. The control device 50 has a control unit 56 that controls the injection unit 20.

[0083] The injection unit 20 includes a plasticizing unit 60 including a flat screw 110, a barrel 120, and a barrel heater 130, a suction and delivery unit 70, and a nozzle 80. A valve 230 is provided in a flow path 140 formed by a communication hole 126 of the barrel 120 and a nozzle hole 82 of the nozzle 80. The valve 230 switches the discharge amount or the presence or absence of discharge of the plasticized material from the nozzle 80. The valve 230 is driven under the control of the control device 50. Other configurations of the injection unit 20 are the same as those of the injection unit 20 in FIG. 2.

[0084] The shaping stage 210 faces the nozzle 80. The plasticized material discharged from the nozzle 80 is deposited on a shaping surface 211 on the shaping stage 210. The shaping surface 211 is configured horizontally with respect to the installation surface of the three-dimensional shaping apparatus 200. The shaping stage 210 is supported by the moving mechanism 220.

[0085] The moving mechanism 220 changes the relative position between the nozzle 80 and the shaping stage 210. The moving mechanism 220 changes the relative position between the nozzle 80 and the shaping stage 210 by moving the shaping stage 210. As an example, the moving mechanism 220 moves the shaping stage 210 by the power generated by the first stage motor 221, the second stage motor 222, and the third stage motor 223. The shaping stage 210 is a three-axis positioner that moves along the three axes of the X-axis, Y-axis, and Z-axis. Each stage motor is driven under the control of the control device 50.

[0086] The moving mechanism 220 may be configured to change the relative position between the nozzle 80 and the shaping stage 210 by moving the plasticizing unit 60 without moving the shaping stage 210. The moving mechanism 220 may be configured to change the relative position between the nozzle 80 and the shaping stage 210 by moving both the shaping stage 210 and the plasticizing unit 60.

[0087] The three-dimensional shaping device 200 ejects the plasticizing material from the nozzle 80 while changing the relative position between the nozzle 80 and the shaping stage 210 under the control of the control device 50. The three-dimensional shaping device 200 laminates a layer of the plasticizing material on the shaping stage 210 to shape a three-dimensional shaped object with a desired shape.

[0088] The control unit 56 of the control device 50 temporarily stops the ejection of the plasticizing material from the nozzle 80 using the valve 230. When the control unit 56 stops the ejection of the plasticizing material, it drives the plunger 78 provided in the suction and delivery unit 70 to perform a suction operation of sucking the plasticizing material from the flow path 140 into the cylinder 73. When restarting the ejection, the control unit 56 drives the plunger 78 to perform a delivery operation of delivering the plasticizing material from the plunger 78 toward the flow path 140.

[0089] The suction and delivery unit 70 has the configuration shown in FIG. 5. The suction and delivery unit 70 includes a cylinder 73, a plunger 78, a motor 150, a ball screw 157, and a nut 159. The motor 150 includes a motor housing 151, a stator 153, and a rotor 155. The motor 150 is a bearingless motor.

[0090] By using a bearingless motor in the suction and delivery unit 70 that constitutes the three-dimensional shaping apparatus 200, the discharge amount of the plasticized material discharged onto the shaping stage 210 becomes stable. Also, the durability of the suction and delivery unit 70 is improved.

Description of Reference Numerals

[0091] 10... Material supply unit, 20... Injection unit, 30... Mold unit, 32... Mold, 34... Cavity, 36... Movable mold, 38... Fixed mold, 40... Mold clamping unit, 42... Mold drive unit, 44... Mold clamping ball screw unit, 50... Control device, 52... Storage unit, 54... Display unit, 56... Control unit, 60... Plasticizing unit, 62... Screw case, 64... Drive motor, 66... Shaft, 70... Suction and delivery unit, 73... Cylinder, 78... Plunger, 80... Nozzle, 82... Nozzle hole, 84... Nozzle opening, 86... Opening and closing mechanism, 100... Injection molding apparatus, 110... Flat screw, 111... Shaft surface, 112... Groove forming surface, 113... Connection surface, 114... First groove, 115... Screw central part, 116... Connection part, 117... Material introduction part, 120... Barrel, 122... Opposing surface, 124... Second groove, 126... Communication hole, 130... Barrel heater, 140... Flow path, 150... Motor, 151... Motor housing, 153... Stator, 155... Rotor, 157... Ball screw, 159... Nut, 161... Joining member, 163... Slot, 165... Coil, 167... Magnet, 171... Inner cylinder, 173... Outer cylinder, 175... Cylinder heater, 200... Three-dimensional shaping apparatus, 210... Shaping stage, 211... Shaping surface, 220... Moving mechanism, 221... First stage motor, 222... Second stage motor, 223... Third stage motor, 230... Valve, N u1 ... First U-phase winding, N u2 ... Second U-phase winding, N u3 ... Third U-phase winding, Nv1 … Phase 1 V-phase winding, N v2 … Phase 2 V-phase winding, N v3 … Phase 3 V-phase winding, N w1 … Phase 1 W-phase winding, N w2 … Phase 2 W-phase winding, N w3 … Phase 3 W-phase winding, R... Rotation axis, R1... First region, R2... Second region, R3... Third region, VS... Virtual central axis, α... First section, β... Second section, γ... Third section.

Claims

1. A plasticizing unit that plasticizes a material to produce a plasticized material; A nozzle having a nozzle opening for discharging the plasticized material to the outside from the nozzle opening; A cylinder communicating with the nozzle opening and connected to a flow path through which the plasticized material flows, a plunger reciprocating in the cylinder, a ball screw configured to be attachable to one end of the plunger, a nut connected to the ball screw, and a suction and discharge unit having a motor for driving the plunger via the ball screw; A control unit, and The control unit causes the suction and discharge unit to perform a suction operation of sucking the plasticized material into the cylinder by moving the plunger in a direction away from the flow path, and a discharge operation of discharging the plasticized material in the cylinder to the flow path by moving the plunger in a direction approaching the flow path. The motor has a rotor and a stator disposed opposite to the rotor. Either the rotor or the stator has a magnet. Either the rotor or the stator is connected to the outer peripheral surface of the nut. The rotor rotates with a gap with respect to the stator by the magnetic force of the magnet. A material discharge device.

2. The rotor supports the nut. The motor moves the plunger by rotating the nut supported by the rotor. The material discharge device according to Claim 1.

3. The cylinder has an inner cylinder defining an inner diameter, an outer cylinder press-fitted on the outer periphery of the inner cylinder, and a cylinder heater disposed between the inner cylinder and the outer cylinder. The material discharge device according to Claim 1.

4. The ball screw is connected to the plunger via a heat insulating member or a gap. The material discharge device according to Claim 1.

5. The outer cylinder is configured to be press-fittable to a second inner cylinder having a second inner diameter different from the inner diameter of the inner cylinder. The material discharge device according to Claim 3.

6. The cylinder heater is a coil heater wound around the inner cylinder. The first number of turns of the coil heater at the central portion of the cylinder is less than the second number of turns of the coil heater at both ends of the cylinder. The material discharge device according to Claim 3.

7. An injection molding apparatus comprising the material discharge device according to claim 1, wherein the nozzle discharges the plasticized material toward a mold. ​

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