Injection molding machine

Abstract

To provide an injection molding machine that can improve energy efficiency without treating the thermal energy generated by a servo amplifier as waste heat.SOLUTION: An injection molding machine 100 is equipped with a servo motor 81, a servo amplifier 51 that supplies power to the servo motor 81, a heat radiation fin 71 that dissipates heat from the servo amplifier 51, a Peltier element P1 located adjacently to the heat radiation fin 71 that generates power due to temperature differences, and an energy storage device 60 configured to store power generated by the Peltier element P1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an injection molding machine including a radiator for radiating heat from a servo amplifier.

Background Art

[0002] In factories, molded products based on resins such as plastics are manufactured using injection molding machines. Since accurate positioning control is required for injection molding processes, servo motors with high accuracy and responsiveness can be adopted in injection molding machines.

[0003] For example, an injection servo motor drives a screw to inject resin into a mold at a set injection speed and pressure. Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-230181) discloses an injection molding machine including a servo amplifier that supplies power to a servo motor. The servo amplifier is provided with cooling fins for efficiently discharging heat generated in the servo amplifier into the air.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-230181), in order to suppress the temperature rise of the servo amplifier, heat generated in the servo amplifier is efficiently discharged into the air through heat dissipation fins. That is, the heat energy generated in the servo amplifier is treated as waste heat. The heat energy discharged into the air is not effectively utilized thereafter, resulting in energy waste.

[0006] This disclosure was made to solve these problems, and its purpose is to provide an injection molding machine that can improve energy efficiency by not treating the thermal energy generated in the servo amplifier as waste heat. [Means for solving the problem]

[0007] An injection molding machine according to one embodiment includes a first heat sink for dissipating heat from a first servo amplifier that supplies power to a first servo motor, a first thermoelectric module arranged adjacent to the first heat sink and generating electricity due to the temperature difference, and a power storage device configured to store the electricity generated by the first thermoelectric module. [Effects of the Invention]

[0008] According to the injection molding machine described herein, the thermal energy generated by the servo amplifier is not treated as waste heat, thereby improving energy efficiency. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram illustrates the external appearance of the injection molding machine and the arrangement of the servo amplifier in Embodiment 1. [Figure 2] This figure shows a perspective view of the servo amplifier, heat sink fins, and Peltier element. [Figure 3] This diagram illustrates an example of the relationship between the operating period of a servo motor and the average temperature of a servo amplifier during injection molding. [Figure 4] This figure shows an example of the average temperature of a servo amplifier. [Figure 5] This is a schematic block diagram of an injection molding machine. [Figure 6] This is a flowchart to explain the cooling control process. [Figure 7] This figure shows an example of the arrangement of a servo amplifier in an injection molding machine according to Modification 1. [Figure 8] This figure shows an example of the arrangement of a servo amplifier in the injection molding machine of Comparative Example 1. [Figure 9]This figure shows an example of the arrangement of a servo amplifier in an injection molding machine of Comparative Example 2. [Figure 10] This diagram illustrates the external appearance of the injection molding machine and the arrangement of the servo amplifier in Modification Example 2. [Figure 11] This figure shows a perspective view of the servo amplifier, heat sink fins, and Peltier element in modified example 2. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. [Embodiment 1] <About injection molding machines> The injection molding machine 100 in Embodiment 1 will be described below with reference to Figure 1. Figure 1 is a diagram illustrating the external appearance of the injection molding machine 100 and the arrangement of the servo amplifiers 51-55 in Embodiment 1. The upper part of Figure 1 shows the external appearance of the injection molding machine 100, and the lower part of Figure 1 shows a magnified view of the servo amplifiers 51-55 housed inside the injection molding machine 100.

[0011] The injection molding machine 100 is mounted on the XY plane. The direction perpendicular to the XY plane is defined as the Z-axis direction. In Figure 1, the positive direction of the Z-axis may be referred to as the top side or upward, and the negative direction as the bottom side or downward. In Embodiment 1, the injection molding machine 100 is shown as a horizontal injection molding machine, but it is not limited to a horizontal type and may be a vertical injection molding machine.

[0012] The injection molding machine 100 comprises a mold clamping device 10 for clamping the mold and an injection device 20 for melting and injecting the injection material. The mold clamping device 10 is positioned on the negative side of the X-axis relative to the injection device 20.

[0013] <About the clamping device> The clamping device 10 includes a bed 11, a fixed platen 12, a clamping housing 13, a movable platen 14, tie bars 15, a clamping mechanism 16, molds 17, 18, and a ball screw 19. The bed 11 holds the components of the clamping device 10 such as the fixed platen 12, the clamping housing 13, and the movable platen 14. The fixed platen 12 is fixed to the bed 11. The clamping housing 13 is configured to be slidable in the X-axis direction on the bed 11. Similarly, the movable platen 14 is configured to be slidable in the X-axis direction on the bed 11.

[0014] The tie bars 15 are disposed between the fixed platen 12 and the clamping housing 13 and connect the fixed platen 12 and the clamping housing 13. The tie bars 15 include a plurality of bars, and the injection molding machine 100 in Embodiment 1 includes four bars as the tie bars 15. In one aspect, the tie bars 15 may include five or more bars.

[0015] The movable platen 14 is configured to be slidable in the X-axis direction between the fixed platen 12 and the clamping housing 13. The clamping mechanism 16 is provided between the clamping housing 13 and the movable platen 14. The clamping housing 13 in Embodiment 1 is configured to include a toggle mechanism. Note that the clamping mechanism 16 may be configured to include a direct-pressure clamping mechanism. The direct-pressure clamping mechanism means a clamping cylinder.

[0016] The molds 17, 18 are respectively fixed to the fixed platen 12 and the movable platen 14 and are provided between the fixed platen 12 and the movable platen 14. The molds 17, 18 are configured to be opened and closed when the clamping mechanism 16 is driven. Hereinafter, the process of transitioning from the state where the molds 17, 18 are separated to the state where they are in close contact is referred to as "mold closing". Also, the process of tightening to fix the state where the molds 17, 18 are in close contact is referred to as "mold clamping". Furthermore, the process of transitioning from the state where the molds 17, 18 are in close contact to the state where they are separated is referred to as "mold opening". The servo motor 81 is a motor used in the mold closing process, the mold clamping process, and the mold opening process. The ball screw 19 opens and closes the clamping mechanism 16 by converting rotational motion into linear motion.

[0017] The injection molding machine 100 performs a process called "protrusion" after the mold opening process. The protrusion process is a process of removing a material such as resin that has been filled in the molds 17 and 18 and then solidified from the molds 17 and 18. The servo motor 82 is a motor used in the protrusion process.

[0018] <Regarding the injection device> The injection device 20 includes a base 21, a heating cylinder 22, a screw 23, a drive device 24, a hopper 25, an injection nozzle 26, a nozzle touch device 27, and a thermocouple 28. The base 21 is disposed on the positive X-axis side of the bed 11 and holds the drive device 24 and the like. Inside the drive device 24, servo motors 84 and 85 are stored.

[0019] The screw 23 is stored inside the heating cylinder 22. The servo motor 84 in the drive device 24 rotates the screw 23 about the X-axis direction as the central axis. That is, the servo motor 84 is a motor used in the plasticization process. The plasticization process is a process of kneading the resin to be injected by heating with the heating cylinder 22 and rotation of the screw 23. Also, the servo motor 85 is driven to slide the screw 23 itself in the X-axis direction. That is, the servo motor 85 is a motor used in the injection process or the pressure holding process. The injection process is a process of injecting the resin plasticized by the plasticization process into the molds 17 and 18. The pressure holding process is a process of holding pressure to hold the resin injected by the injection process in the molds 17 and 18.

[0020] The hopper 25 is a container that holds a material such as resin before being plasticized and is provided on the positive Z-axis side of the heating cylinder 22. The injection nozzle 26 is provided at the end on the negative X-axis side of the heating cylinder 22. The nozzle touch device 27 slides the injection device 20 in the X-axis direction to bring the injection nozzle 26 into contact with a sprue bush (not shown) of the mold 18. The thermocouple 28 is disposed near the injection nozzle 26 and near the heating cylinder 22. The thermocouple 28 is a temperature sensor that detects the temperature of the heating cylinder 22 where the thermocouple 28 is disposed.

[0021] The control panel 30 is located on the negative side of the Y-axis of the injection molding machine 100. The control panel 30 may be provided separately from the injection molding machine 100. The control panel 30 includes a display 31 and an input device 32. The input device 32 includes, for example, a number of buttons. In some cases, the control panel 30 may include multiple displays and speakers, and the display 31 and the input device 32 may be integrated as a touch panel.

[0022] The lower part of Figure 1 shows a magnified view of the servo amplifiers 51-55 housed within the base 21. The servo amplifiers 51-55 are arranged along the X-axis. Servo amplifier 51 supplies three-phase AC power to the servo motor 81 used in the mold closing, mold clamping, and mold opening processes. Servo amplifier 52 supplies three-phase AC power to the servo motor 82 used in the ejection process.

[0023] Servo amplifier 53, together with servo amplifier 51, supplies three-phase AC power to servo motor 81 used in the mold closing, mold clamping, and mold opening processes. Servo amplifier 54 supplies three-phase AC power to servo motor 84 used in the plasticizing process. Servo amplifier 55 supplies three-phase AC power to servo motor 85 used in the injection and holding pressure processes. In Embodiment 1, servo motors 81, 82, 84, and 85 are AC servo motors, but DC servo motors may also be used. Heat dissipation fins 71 to 75 are attached to the negative side of the Y-axis of servo amplifiers 51 to 55, respectively. The heat dissipation fins 71 to 75 dissipate heat from servo amplifiers 51 to 55, respectively.

[0024] The control device 40 includes a CPU, memory, etc. The control device 40 acquires detection values ​​from various sensors and comprehensively controls the injection molding machine 100. The detection values ​​from various sensors include, for example, temperature information from servo amplifiers 51-55, temperature information from the heating cylinder 22, and position information from various movable parts such as the clamping mechanism 16, molds 17, 18, and injection nozzle 26.

[0025] The injection molding machine 100 in Embodiment 1 includes Peltier elements P1 to P4 and an energy storage device 60. The Peltier elements P1 to P4 in Embodiment 1 are arranged to be in contact with at least a portion of the heat dissipation fins located at both ends. The Peltier elements P1 to P4 are semiconductor elements capable of generating electricity by the Seebeck effect due to the temperature difference between the ends of the element, and are semiconductor elements capable of temperature control by utilizing cooling and heating by the Peltier effect by applying a DC current. Each of the Peltier elements P1 to P4 is electrically connected to the energy storage device 60. The energy storage device 60 is configured to be able to store the electricity generated by each of the Peltier elements P1 to P4. The energy storage device 60 is, for example, a battery. The energy storage device 60 can supply the stored electricity to various devices included in the injection molding machine 100.

[0026] <Power generation and heat transfer using Peltier elements> Figure 2 shows a perspective view of the servo amplifiers 51-55, heat sink fins 71-75, and Peltier elements P1-P4. Figure 2 shows the servo amplifiers 51-55, heat sink fins 71-75, and Peltier elements P1-P4 arranged along the X-axis. The heat sink fins 71-75 are, for example, heat sink type heat sinks and have a shape that ensures a large heat dissipation area in order to efficiently release heat into the air.

[0027] As described above, in Embodiment 1, the actual Peltier elements P1 to P4 are arranged so as to be in contact with at least a portion of the heat sink fins. However, in Figure 2, for illustrative purposes, the Peltier elements P1 to P4 are shown separated from the heat sink fins. Peltier element P1 is positioned between heat sink fins 71 and 72. Peltier element P2 is positioned between heat sink fins 72 and 73. Peltier element P3 is positioned between heat sink fins 73 and 74. Peltier element P4 is positioned between heat sink fins 74 and 75.

[0028] Each of the Peltier elements P1 to P4 has a flat plate shape. For example, Peltier element P1, which is positioned adjacent to the heat dissipation fins 71 and 72, has a surface SN on the negative X-axis side and a surface SP on the positive X-axis side. Peltier element P1 generates electricity based on the temperature difference between surface SN and surface SP. The larger the temperature difference between surface SN and surface SP, the greater the amount of electricity generated by Peltier element P1.

[0029] Surface SN is in contact with at least a portion of the heat dissipation fin 71. That is, surface SN exchanges heat with the heat dissipation fin 71. Surface SP is in contact with at least a portion of the heat dissipation fin 72. That is, surface SP exchanges heat with the heat dissipation fin 72. If the temperature difference between the heat dissipation fin 71 and the heat dissipation fin 72 is large, the temperature difference between surface SN and surface SP will also be large, and the amount of power generated by the Peltier element P1 will increase. The power generated by the Peltier element P1 is output to the energy storage device 60.

[0030] In this way, the Peltier element P1 generates electricity using the temperature difference with the heat dissipation fins 71 and 72, and outputs the generated electricity to the energy storage device 60. Peltier elements P2 to P4 generate electricity in the same way, and output the generated electricity to the energy storage device 60 using the temperature difference with the heat dissipation fins at both ends. As a result, in the injection molding machine 100 of Embodiment 1, the thermal energy generated by the servo amplifier 51 is not treated as waste heat, but is converted into electrical energy by the Peltier element P1 and stored in the energy storage device 60, thereby improving energy efficiency. In other words, in the injection molding machine 100 of Embodiment 1, thermal energy can be recovered as electrical energy and reused. Note that the shape of the Peltier element P1 is not limited to a flat plate shape, as long as one end of the element exchanges heat with the heat dissipation fin 71 and the other end exchanges heat with the heat dissipation fin 72.

[0031] Furthermore, since the thermal resistance of Peltier elements P1 to P4 is smaller than that of air, each of Peltier elements P1 to P4 functions as a heat transfer member. That is, by placing Peltier element P1 between heat dissipation fins 71 and 72, the efficiency of heat exchange between heat dissipation fins 71 and 72 is improved. As a result, in the injection molding machine 100 of Embodiment 1, heat exchange between heat dissipation fins 71 and 72 is promoted by Peltier element P1, so that heat can be dissipated from one servo amplifier using multiple heat dissipation fins. In other words, in the injection molding machine 100 of Embodiment 1, the surface area of ​​the heat dissipation fins for one servo amplifier is increased, so the overall heat dissipation rate of the injection molding machine 100 is improved.

[0032] Specifically, for example, when the temperature of the servo amplifier 51 rises excessively, the heat generated in the servo amplifier 51 is first transferred to the heat sink fin 71. Then, because the Peltier element P1 functions as a heat transfer element, if the temperature of the heat sink fin 72 is lower than the temperature of the heat sink fin 71, the heat transferred from the servo amplifier 51 to the heat sink fin 71 is transferred to the heat sink fin 72 via the Peltier element P1. Furthermore, if the temperature of the heat sink fin 73 is lower than the temperature of the heat sink fin 72, the heat transferred from the heat sink fin 71 to the heat sink fin 72 can be transferred to the heat sink fin 73 via the Peltier element P2.

[0033] In this way, by arranging the Peltier elements P1 to P4 between each of the heat dissipation fins 71 to 75, the injection molding machine 100 in Embodiment 1 can efficiently dissipate the heat from the servo amplifier 51 via the Peltier elements P1 to P4 using the heat dissipation fins 72 to 75. That is, the heat generated in the servo amplifier 51 can be dissipated not only by the heat dissipation fin 71 but also by the heat dissipation fins 72 to 75.

[0034] <Servo amplifier temperature> Figure 3 illustrates an example of the relationship between the drive period of servo motors 81, 82, 84, and 85 and the average temperature of servo amplifiers 51-55 during the injection molding process. The injection molding process includes a mold closing process, a mold clamping process, an injection process, a holding pressure process, a cooling process, a mold opening process, an ejection process, and a plasticizing process. The injection molding machine 100 repeatedly executes the above injection molding process cycle. Figure 3 shows an example of the drive period of servo motors 81, 82, 84, and 85 in one cycle in Embodiment 1. The period from timing t1 to t8 represents the period of one injection molding process cycle. Note that the period during which each process is performed will differ from the period shown in Figure 3 depending on the settings and molding method.

[0035] First, the mold closing process is performed during the period from timing t1 to t2. That is, the servo motor 81 for mold closing is driven during the period from timing t1 to t2. The mold clamping process is performed during the period from timing t2 to t5. That is, the servo motor 81 for mold clamping is driven during the period from timing t2 to t5. The injection process is performed during the period from timing t2 to t3. That is, the servo motor 85 for injection is driven during the period from timing t2 to t3. Also, the holding pressure process is performed during the period from timing t3 to t4. That is, the servo motor 85 for holding pressure is driven during the period from timing t3 to t4. The period from timing t4 to timing t5 is a cooling period for cooling the resin and other materials injected into the molds 17 and 18.

[0036] The mold opening process is performed during the period from timing t5 to t6. That is, the servo motor 81 for mold opening is driven during the period from timing t5 to t6. The ejection process is performed during the period from timing t6 to t7. That is, the servo motor 82 for ejection is driven during the period from timing t6 to t7. The plasticization process is performed during the period from timing t4 to t7. That is, the servo motor 84 for plasticization is driven during the period from timing t4 to t7.

[0037] Thus, the driving periods of each servo motor 81, 82, 84, and 85 within one cycle are different from each other. Furthermore, the torque generated by each servo motor 81, 82, 84, and 85 is also different from each other. In other words, the power supplied by each servo amplifier 51 to 55 is also different from each other, and the average temperatures of the servo amplifiers 51 to 55 are also different from each other.

[0038] Figure 4 shows an example of the average temperature of servo amplifiers 51 to 55. As described above, the average temperature of servo amplifiers 51 to 55 is affected by the drive period and torque of each servo motor 81, 82, 84, and 85. The torque required to perform the plasticization process is higher than the torque required to perform other processes. Therefore, servo motor 84 is subjected to a high load. Furthermore, in the example of Embodiment 1, servo motors 81 and 85 are subjected to a medium load, and servo motor 82 is subjected to a low load. The average temperature of servo amplifier 54, which supplies power to servo motor 84, which is subjected to a high load, is 90°C. The average temperature of servo amplifier 52, which supplies power to servo motor 82, which is subjected to a low load, is 30°C. Subsequently, the average temperature of servo amplifier 55, which supplies power to servo motor 85, which is subjected to a medium load, is 60°C.

[0039] Similar to servo motor 85, servo motor 81 is subjected to a moderate load, but the power supplied to servo motor 81 is evenly distributed between the power supplied by servo amplifier 51 and the power supplied by servo amplifier 53. As a result, the average temperatures of servo amplifier 51 and servo amplifier 53 are below 60°C, and are both 45°C.

[0040] In the injection molding machine 100 of Embodiment 1, a servo amplifier 52 with an average temperature of 30°C is placed between servo amplifiers 51 and 53, both of which have an average temperature of 45°C. That is, a heat dissipation fin 72 is placed between heat dissipation fins 71 and 73, which are the heat dissipation targets for servo amplifiers 51 and 53 that supply power to the same servo motor 81. If servo amplifiers 51 and 53, both with an average temperature of 45°C, are placed adjacent to each other, the temperature difference between heat dissipation fins 71 and 73 becomes small, and even if a Peltier element is placed between heat dissipation fins 71 and 73, the amount of power generated by the Peltier element will be small.

[0041] In the injection molding machine 100 of Embodiment 1, a servo amplifier 52 that supplies power to the servo motor 82 is positioned between servo amplifiers 51 and 53, both having an average temperature of 45°C. As a result, in the injection molding machine 100 of Embodiment 1, even when multiple servo amplifiers are connected to the same servo motor, a decrease in the amount of power generated by the Peltier element can be suppressed by positioning a servo amplifier that supplies power to other servo motors between multiple servo amplifiers that supply power to the same servo motor.

[0042] <Schematic block diagram of an injection molding machine> Figure 5 is a schematic block diagram of the injection molding machine 100. Figure 5 shows the connection relationships between the control device 40, servo amplifiers 51-55, servo motors 81, 82, 84, 85, Peltier elements P1-P4, and energy storage device 60. In Figure 5, the explanation of the configuration and connection relationships already explained in Figure 1 is not repeated.

[0043] As shown in Figure 5, the injection molding machine 100 in Embodiment 1 is equipped with temperature sensors H1 to H5. The temperature sensors H1 to H5 are attached to the servo amplifiers 51 to 55, respectively, and detect the temperature of the servo amplifiers 51 to 55, respectively.

[0044] Each of the Peltier elements P1 to P4 is connected to a rectifier circuit Rc1 to Rc4. The rectifier circuits Rc1 to Rc4 are full-wave rectifier circuits that rectify the negative voltage input from the Peltier elements P1 to P4 into a positive voltage and output it to the energy storage device 60. If the current input from the Peltier elements P1 to P4 is a positive voltage, the rectifier circuits Rc1 to Rc4 output it to the energy storage device 60 as a positive voltage. In other words, regardless of whether the current input from the Peltier elements P1 to P4 is a negative or positive voltage, the rectifier circuits Rc1 to Rc4 output a positive DC current to the energy storage device 60.

[0045] The Peltier element P1 generates electricity using the Seebeck effect, utilizing the temperature difference between the surface SN facing the heat sink fin 71 and the surface SP facing the heat sink fin 72. The direction of the current flowing from the Peltier element P1 is determined by which surface has a higher temperature, SP or SN. For example, if the temperature of surface SP is higher than the temperature of surface SN, the current input from the Peltier element P1 will be a positive voltage. In this case, if the temperature of surface SN is higher than the temperature of surface SP, the current input from the Peltier element P1 will be a negative voltage.

[0046] In the injection molding machine 100 of Embodiment 1, a rectifier circuit Rc1 is provided between the Peltier element P1 and the energy storage device 60. Therefore, if there is a temperature difference between the temperature of surface SP and the temperature of surface SN, a positive voltage current can be output to the energy storage device 60 regardless of which of the two temperatures is greater. In other words, in the injection molding machine 100 of Embodiment 1, the generated power can be stored in the energy storage device 60 regardless of the direction of the current flowing from the Peltier element P1. The rectifier circuits Rc1 to Rc4 include switch circuits and are configured to supply current input from the control device 40 to the Peltier elements P1 to P4, respectively.

[0047] The internal configuration of the control device 40 will now be described. The control device 40 comprises a control unit 41, an input interface 42, an output interface 43, and a storage device 44. The control unit 41 comprises a CPU 41a and a memory 41b.

[0048] The CPU 41a loads the program stored in ROM into RAM and executes it. Memory 41b includes ROM (Read Only Memory) and RAM (Random Access Memory) and stores the program executed by the CPU 41a.

[0049] In some cases, the control unit 41 may be configured by a dedicated hardware circuit. That is, the control unit 41 may be implemented by an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), etc. Alternatively, the control unit 41 may be implemented by appropriately combining a processor, memory, ASIC, FPGA, etc. The storage device 44 may be configured to include, for example, an HDD (Hard Disk Drive) or an SSD (Flash Solid State Drive).

[0050] The control unit 41 receives detected values ​​from various sensors, such as temperature sensors H1 to H5, attached to each servo amplifier 51 to 55, via the input interface 42. The control unit 41 also receives feedback signals from each servo motor 81, 82, 84, and 85 via the input interface 42.

[0051] The control unit 41 can send control commands to the servo amplifiers 51-55 via the output interface 43. The control unit 41 can also output a DC current to the Peltier elements P1-P4 via the output interface 43.

[0052] As a result, the control device 40 can control the temperature around the Peltier elements P1 to P4 by the Peltier effect. Specifically, when a DC current is input to the Peltier element P1 by the control device 40, one of its surfaces SN and SP becomes a heat-absorbing surface and the other becomes a heat-dissipating surface. The heat-absorbing and heat-dissipating surfaces are reversed depending on whether the DC current input from the control device 40 is a positive or negative voltage. In other words, the heat-absorbing and heat-dissipating surfaces are reversed depending on the direction of the DC current flowing through the Peltier element P1. The control device 40 can change the amount of heat absorbed and dissipated by the Peltier elements P1 to P4 according to the magnitude of the DC current it outputs.

[0053] <Cooling control using Peltier elements> Figure 6 is a flowchart illustrating the cooling control process. Below, we will describe the cooling control performed on any of the servo amplifiers 51 to 55 when its temperature rises excessively. In the example in Figure 6, we will describe the cooling process for servo amplifier 51.

[0054] The CPU 41a determines whether the value detected by the temperature sensor H1 exceeds a threshold (step S10). The threshold is stored in the memory device 44, and the value at which cooling by the Peltier effect of the Peltier element P1 is required can be predetermined by experimentation or other means. As described above, the CPU 41a obtains the value detected by the temperature sensor H1 via the input interface 42. If the value detected by the temperature sensor H1 does not exceed the threshold (NO in step S10), the CPU 41a repeats the process in step S10.

[0055] If the temperature sensor H1 detects a value that exceeds a threshold (YES in step S10), the CPU 41a supplies power to the Peltier element P1 to cool the servo amplifier 51 (step S20). More specifically, the CPU 41a outputs a DC current to the Peltier element P1 such that the surface SN of the Peltier element P1 becomes a heat-absorbing surface. As a result, the heat from the heat dissipation fin 71 facing surface SN is absorbed. In other words, the Peltier element P1 cools the heat dissipation fin 71.

[0056] As a result, in the injection molding machine 100 of Embodiment 1, by cooling the heat dissipation fins 71 that dissipate heat from the servo amplifier 51, which has become excessively hot, heat dissipation from the servo amplifier 51 by the heat dissipation fins 71 can be promoted, and an excessive temperature rise of the servo amplifier 51 can be suppressed.

[0057] Figure 6 illustrates the cooling control for servo amplifier 51, but similar cooling control is performed for servo amplifiers 52-55. For servo amplifiers 52-54, CPU 41a cools the heat sink using two Peltier elements. Specifically, for example, when the temperature of servo amplifier 52 exceeds a threshold and the heat sink fin 72 needs to be cooled, CPU 41a outputs current such that the surface SP of Peltier element P1 becomes the heat-absorbing surface, and the negative X-axis side of Peltier element P2 becomes the heat-absorbing surface. As a result, the heat sink fin 72 is efficiently cooled by both Peltier element P1 and Peltier element P2.

[0058] In Embodiment 1, the servo motor 81 may correspond to the "first servo motor" in this disclosure. The servo amplifier 51 may correspond to the "first servo amplifier" in this disclosure. The heat sink fin 71 may correspond to the "first heat sink" in this disclosure. The Peltier element P1 may correspond to the "first thermoelectric module" in this disclosure. The servo motor 82 may correspond to the "second servo motor" in this disclosure. The servo amplifier 52 may correspond to the "second servo amplifier" in this disclosure. The heat sink fin 72 may correspond to the "second heat sink" in this disclosure. The servo amplifier 53 may correspond to the "third servo amplifier" in this disclosure. The heat sink fin 73 may correspond to the "third heat sink" in this disclosure. The Peltier element P2 may correspond to the "second thermoelectric module" in this disclosure. The temperature sensor H1 may correspond to the "first temperature sensor" in this disclosure.

[0059] <Example 1> In Embodiment 1, an example was described using an injection molding machine 100 in which multiple servo amplifiers supply power to the same servo motor. In Modification 1, an example of servo amplifier arrangement in a configuration in which each servo amplifier supplies power to different servo motors is described. In Modification 1, the description of the same configuration as in Embodiment 1 is not repeated.

[0060] Figure 7 shows an example of the arrangement of servo amplifiers in the injection molding machine 100A of Modification 1. As shown in Figure 7, the injection molding machine 100A in Modification 1 is equipped with servo motors 81A, 82A, and 83A and servo amplifiers 51A, 52A, and 53A. Servo amplifiers 51A to 53A supply power to the servo motors 81A to 83A, respectively.

[0061] The servo amplifiers 51A to 53A are arranged in the order of 51A, 52A, and 53A along the X-axis. A Peltier element P1 is placed between the heat sink fin 71 of servo amplifier 51A and the heat sink fin 72 of servo amplifier 52A. A Peltier element P2 is placed between the heat sink fin 72 of servo amplifier 52A and the heat sink fin 73 of servo amplifier 53A.

[0062] Figure 7 shows the average temperatures of servo amplifiers 51A to 53A when the injection molding machine 100A is in operation. Operation of the injection molding machine 100A means when the injection molding process is being performed. The average temperature is the average of the values ​​detected by temperature sensors H1 to H5 during the injection molding process.

[0063] The average temperatures of servo amplifiers 51A to 53A do not need to be measured values; for example, they may be average temperatures calculated in advance through experiments, or they may be predetermined based on the operating period of the servo motors to which power is supplied. In other words, the average temperature of the servo amplifiers may be estimated based on which servo motors are used in which processes the power is supplied to. As shown in Figure 7, the average temperature of servo amplifier 51A is 65°C. The average temperature of servo amplifier 52A is 90°C. The average temperature of servo amplifier 53A is 60°C.

[0064] In Modification 1, the arrangement order of servo amplifiers 51A to 53A is determined based on the average temperature of servo amplifiers 51A to 53A. More specifically, as shown in Figure 7, the temperature difference between servo amplifier 51A and servo amplifier 52A is 25°C. The temperature difference between servo amplifier 52A and servo amplifier 53A is 30°C. The amount of power generated by Peltier elements P1 and P2 is affected by the temperature difference of the servo amplifiers placed at both ends. That is, a larger temperature difference with servo amplifiers 51A and 52A results in a larger amount of power generated by Peltier element P1, and a larger temperature difference with servo amplifiers 52A and 53A results in a larger amount of power generated by Peltier element P2.

[0065] As shown in Figure 7, the total temperature difference between servo amplifiers 51A and 52A, plus the temperature difference between servo amplifiers 51A and 52A, is 55°C. In Modification 1, servo amplifiers 51A to 53A are arranged such that the total temperature difference between servo amplifiers 51A and 52A, plus the temperature difference between servo amplifiers 51A and 52A, is large.

[0066] Figure 8 shows an example of the arrangement of servo amplifiers in the injection molding machine 100Z1 of Comparative Example 1. In Comparative Example 1, servo amplifiers 51A to 53A are arranged in the order of servo amplifiers 52A, 51A, and 53A along the X-axis. As a result, as shown in Figure 8, the temperature difference between servo amplifier 52A and servo amplifier 51A is 25°C, and the temperature difference between servo amplifier 51A and servo amplifier 53A is 5°C. That is, the total temperature difference, which is the temperature difference between servo amplifiers 52A and 51A and the temperature difference between servo amplifiers 51A and 53A, is 30°C.

[0067] Furthermore, Figure 9 shows an example of the arrangement of servo amplifiers in the injection molding machine 100Z2 of Comparative Example 2. In Comparative Example 2, servo amplifiers 51A to 53A are arranged in the order of servo amplifiers 51A, 53A, and 52A along the X-axis. As a result, as shown in Figure 9, the temperature difference between servo amplifier 51A and servo amplifier 53A is 5°C, and the temperature difference between servo amplifier 52A and servo amplifier 53A is 30°C. That is, the total temperature difference between servo amplifiers 51A and 53A, and between servo amplifiers 53A and 52A, is 35°C.

[0068] Thus, the injection molding machine 100A of Modified Example 1 has a configuration in which servo amplifiers 51A to 53A are arranged based on the average temperature of the servo amplifiers 51A to 53A. This maximizes the temperature difference between the Peltier elements P1 and P2, thereby increasing the power generation of the Peltier elements P1 and P2. Note that the number of servo amplifiers is not limited to three, but may be four or more. In other words, the number of Peltier elements is not limited to two, but may be three or more. Even in this case, in the injection molding machine 100A of Modified Example 1, each servo amplifier is arranged based on the average temperature of the servo amplifiers in order to increase the power generation of three or more Peltier elements.

[0069] In Modification 1, servo motors 81A to 83A may correspond to the "first servo motor to third servo motor" in this disclosure. Servo amplifiers 51A to 53A may correspond to the "first servo amplifier to third servo amplifier" in this disclosure. Peltier elements P1 and P2 may correspond to the "first thermoelectric module" and "second thermoelectric module" in this disclosure.

[0070] <Modification 2> In Embodiment 1, an example in which Peltier elements are placed between arranged servo amplifiers was described using an injection molding machine 100. In Modification 2, an example in which Peltier elements are placed not only between the servo amplifiers but also at the ends of the arranged servo amplifiers is described. In Modification 2, the description of the same configuration as in Embodiment 1 is not repeated.

[0071] Figure 10 is a diagram illustrating the external appearance of the injection molding machine 100B and the arrangement of servo amplifiers 51-55 in Modification 2. As shown in Figure 10, in Modification 2, a Peltier element PL is positioned on the negative X-axis side of servo amplifier 51. A Peltier element PR is positioned on the positive X-axis side of servo amplifier 55.

[0072] Peltier element PL generates electricity using the temperature difference between the air temperature and the heat dissipation fin 71. Peltier element PR generates electricity using the temperature difference between the heat dissipation fin 75 and the air temperature. The air temperature is, for example, 25°C. Each of Peltier elements PL and PR is connected to the energy storage device 60.

[0073] Figure 11 shows a perspective view of the servo amplifiers 51-55, heat sink fins 71-75, and Peltier elements PL, P1-P4, PR in modified example 2. As shown in Figure 11, the Peltier element PL has a flat plate shape including a face SNL on the negative X-axis side and a face SPL on the positive X-axis side.

[0074] Surface SPL is in contact with the heat dissipation fins 71. That is, surface SPL exchanges heat with the heat dissipation fins 71. On the other hand, surface SNL is not in contact with any of the heat dissipation fins 71-75 and is exposed. That is, none of the heat dissipation fins 71-75 are located in the direction normal to surface SNL. Therefore, surface SNL exchanges heat with the air in the space VS in the direction normal to surface SNL. As mentioned above, the temperature of the air in the space VS is, for example, 25°C. As a result, electricity is generated by the Peltier element PL due to the temperature difference between the heat dissipation fins 71 and the air in the space VS, and waste heat can be reused.

[0075] In Modification 2, servo motors 81 and 82 may correspond to the "first servo motor" and "second servo motor" in this disclosure. Servo amplifiers 51 and 52 may correspond to the "first servo amplifier" and "second servo amplifier" in this disclosure. Peltier element PL may correspond to the "first thermoelectric module" in this disclosure. Surface SPL may correspond to the "first surface" in this disclosure. Surface SNL may correspond to the "second surface" in this disclosure.

[0076] [Note] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0077] (Article 1) An injection molding machine according to one embodiment comprises a first servo motor, a first servo amplifier that supplies power to the first servo motor, a first heat sink that dissipates heat from the first servo amplifier, a first thermoelectric module arranged adjacent to the first heat sink and generating power by the temperature difference, and a power storage device configured to store the power generated by the first thermoelectric module.

[0078] According to the injection molding machine described in paragraph 1, it is possible to reuse the waste heat from the heat sink that dissipates heat from the servo amplifier.

[0079] (Article 2) In the injection molding machine according to Article 1, the injection molding machine further comprises a second servo motor, a second servo amplifier that supplies power to the second servo motor, and a second heat sink that dissipates heat from the second servo amplifier. The first thermoelectric module is placed between the first heat sink and the second heat sink and generates electricity due to the temperature difference between the first heat sink and the second heat sink.

[0080] According to the injection molding machine described in paragraph 2, the first thermoelectric module, which functions as a heat transfer member, promotes heat exchange between the first heat sink and the second heat sink, thereby increasing the capacity of the heat sink for one servo amplifier and enabling the reuse of waste heat.

[0081] (Article 3) In the injection molding machine relating to Article 2, the injection molding machine further comprises, together with the first servo amplifier, a third servo amplifier that supplies power to the first servo motor, and a third heat sink that dissipates heat from the third servo amplifier. The second heat sink is positioned between the first heat sink and the third heat sink.

[0082] According to the injection molding machine described in paragraph 3, when multiple amplifiers supply power to one motor, the reduction in power generation efficiency by the thermoelectric module can be suppressed by placing the heat sinks of other amplifiers between the heat sinks of the multiple amplifiers.

[0083] (Article 4) In the injection molding machine relating to Articles 1 to 3, the injection molding machine further comprises a first temperature sensor for detecting the temperature of the first servo amplifier and a control device for supplying power to the first thermoelectric module. When the value detected by the first temperature sensor exceeds a predetermined threshold, the control device supplies power to the first thermoelectric module to cool the first heat sink.

[0084] According to the injection molding machine described in paragraph 4, by cooling the heat sink that dissipates heat from the servo amplifier, heat dissipation from the servo amplifier by the heat sink can be promoted, and the temperature rise of the servo amplifier can be suppressed.

[0085] (Article 5) In the injection molding machine according to Article 2, the injection molding machine further comprises a third servo amplifier that supplies power to a third servo motor, a third heat sink that dissipates heat from the third servo amplifier, and a second thermoelectric module positioned between the second heat sink and the third heat sink and generating electricity due to the temperature difference between the second heat sink and the third heat sink. When the injection molding machine is in operation, the average temperature of the first servo amplifier is the first temperature, the average temperature of the second servo amplifier is the second temperature, and the average temperature of the third servo amplifier is the third temperature. The temperature difference between the first temperature and the second temperature is the first temperature difference, the temperature difference between the second temperature and the third temperature is the second temperature difference, and the temperature difference between the first temperature and the third temperature is the third temperature difference. The sum of the first temperature difference and the second temperature difference is greater than the sum of the second temperature difference and the third temperature difference and the sum of the first temperature difference and the third temperature difference.

[0086] According to the injection molding machine described in Section 4, the amount of power generated by each thermoelectric module can be increased by arranging each servo amplifier so that the temperature difference between each thermoelectric module is maximized.

[0087] (Article 6) In the injection molding machine according to Article 1 or Article 4, the injection molding machine further comprises a second servo motor, a second servo amplifier that supplies power to the second servo motor, and a second heat sink that dissipates heat from the second servo amplifier. The first thermoelectric module has a shape having a first surface and a second surface, the first surface being in contact with the first heat sink and the second surface being exposed.

[0088] According to the injection molding machine described in paragraph 4, the first thermoelectric module generates electricity from the temperature difference between the first heat sink and the air, enabling the reuse of waste heat.

[0089] (Clause 7) The injection molding machine relating to paragraphs 1 to 6 further comprises a full-wave rectifier circuit positioned between the first thermoelectric module and the energy storage device.

[0090] According to the injection molding machine described in paragraph 7, power can be supplied to the energy storage device regardless of the direction of the current generated by the first thermoelectric module. [Explanation of Symbols]

[0091] 10 Clamping device, 11 Bed, 12 Fixed platen, 13 Clamping housing, 14 Movable platen, 15 Tie bar, 16 Clamping mechanism, 17,18 Mold, 19 Ball screw, 20 Injection device, 21 Base, 22 Heating cylinder, 23 Screw, 24 Drive device, 25 Hopper, 26 Injection nozzle, 27 Nozzle touch device, 28 Thermocouple, 30 Control panel, 31 Display, 32 Input device, 40 Control device, 41 Control unit, 41b Memory, 42 Input interface, 43 Output interface, 44 Storage device, 51-55 Servo amplifier, 60 Energy storage device, 71-75 Heat dissipation fins, 81-85 Servo motor, 100, 100A, 100B Injection molding machine, H1-H5 Temperature sensor, P1-P4, PL, PR Peltier element, Rc1~Rc4 rectifier circuit, SN, SNL, SP, SPL planes, t1~t8 timing.

Claims

1. First servo motor and A first servo amplifier that supplies power to the first servo motor, A first heat sink for dissipating heat from the first servo amplifier, A first thermoelectric module is positioned adjacent to the first heat sink and generates electricity based on the temperature difference, A power storage device configured to store the electricity generated by the first thermoelectric module, The second servo motor and A second servo amplifier that supplies power to the second servo motor, The system comprises a second heat sink for dissipating heat from the second servo amplifier, The first thermoelectric module is positioned between the first heat sink and the second heat sink, and generates electricity due to the temperature difference between the first heat sink and the second heat sink in an injection molding machine.

2. A third servo amplifier, along with the first servo amplifier, supplies power to the first servo motor. The system further comprises a third heat sink for dissipating heat from the third servo amplifier, The injection molding machine according to claim 1, wherein the second heat sink is disposed between the first heat sink and the third heat sink.

3. A first temperature sensor for detecting the temperature of the first servo amplifier, The system further comprises a control device that supplies power to the first thermoelectric module, The injection molding machine according to claim 1, wherein the control device supplies power to the first thermoelectric module to cool the first heat sink when the detected value of the first temperature sensor exceeds a predetermined threshold.

4. A third servo amplifier that supplies power to the third servo motor, A third heat sink for dissipating heat from the third servo amplifier, The system further comprises a second thermoelectric module positioned between the second heat sink and the third heat sink, which generates electricity due to the temperature difference between the second heat sink and the third heat sink, During the operation of the injection molding machine, The average temperature of the first servo amplifier is the first temperature. The average temperature of the second servo amplifier is the second temperature. The average temperature of the third servo amplifier is the third temperature. The temperature difference between the first temperature and the second temperature is the first temperature difference. The temperature difference between the second temperature and the third temperature is the second temperature difference. The temperature difference between the first temperature and the third temperature is the third temperature difference. The injection molding machine according to claim 1, wherein the sum of the first temperature difference and the second temperature difference is greater than the sum of the second temperature difference and the third temperature difference and the sum of the first temperature difference and the third temperature difference.

5. The injection molding machine according to any one of claims 1 to 4, further comprising a full-wave rectifier circuit disposed between the first thermoelectric module and the energy storage device.

6. A first servo motor and A first servo amplifier that supplies power to the first servo motor, A first heat sink for dissipating heat from the first servo amplifier, A first thermoelectric module is positioned adjacent to the first heat sink and generates electricity based on the temperature difference, A power storage device configured to store the electricity generated by the first thermoelectric module, The second servo motor and A second servo amplifier that supplies power to the second servo motor, The system comprises a second heat sink for dissipating heat from the second servo amplifier, The first thermoelectric module has a shape having a first surface and a second surface, The first surface is in contact with the first heat sink, The second surface is an exposed injection molding machine.

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