A heating system and an injection molding machine

Abstract

An embodiment of the present invention relates to the technical field of injection molding machines, and discloses a heating system that can be applied to an injection molding machine. The system includes a heating control circuit, a power distribution module, a temperature control module, and a heating coil. Among them, the power distribution module borrows the function of the frequency converter to convert AC mains into DC power output. The output end of the power distribution module is connected to the input end of the heating control circuit, and the output end of the temperature control module is also connected to the input end of the heating control circuit. The heating control circuit is used to control the heating temperature of the heating coil according to the control signal of the temperature control module. The output end of the heating control circuit is connected to the heating coil. At the same time, in the embodiment of the present invention, the heating coil is used as the braking unit of the frequency converter, and the heating coil can directly draw power from the DC of the frequency converter, thereby greatly increasing the overall power consumption efficiency of the injection molding machine, reducing system losses, and lowering equipment costs.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of injection molding machines, and particularly to a heating system and an injection molding machine. Background Art

[0002] An injection molding machine, also known as an injection molding press or an injection machine, is the main molding equipment for manufacturing various shaped plastic products by using a plastic molding die for thermoplastic or thermosetting plastics. The injection molding machine can heat the plastic, apply high pressure to the molten plastic, and inject it to fill the mold cavity. Among them, the heating system of the injection molding machine mainly consists of a temperature controller, a heating control circuit, and a heating coil. The heating control circuit receives the control signal from the temperature controller and controls the alternating current from the outside to be applied to the heating coil to control the heating temperature, mainly including IO, switching devices, protection devices, etc.

[0003] In the process of implementing the embodiments of the present invention, the inventors found that at least the following problems exist in the above related technologies:

[0004] 1. As a traditional heating control and protection device, the contactor + circuit breaker has a relatively long response time, generally at least 20 ms. Often, before the circuit breaker disconnects, the solid-state relay or contactor as the switching device has been burned out, and problems such as adhesion may occur. In the working conditions of the injection molding machine, the probability of short circuit of the heating coil is relatively high. Especially for the heating coil of the nozzle, there is often molten plastic overflow, resulting in short circuit or overload of the heating coil, which causes the staff to frequently replace the coil, and even the contactor or solid-state relay, affecting the production downtime and reducing the production efficiency.

[0005] 2. The injection molding machine is a large power consumer. The power consumption is mainly composed of the injection power part and the plastic heating part, and the power consumption ratio is between 3:1 and 4:1. In recent years, the servo transformation has been promoted to reduce the power consumption of the power part, but the energy consumption of the heating part cannot be reduced, and the braking energy consumption of the servo motor itself in the power part is wasted on the resistor. Summary of the Invention

[0006] Aiming at the above-mentioned defects of the prior art, the purpose of the embodiments of the present invention is to provide a heating system and an injection molding machine that can improve the overall efficiency of the injection molding machine.

[0007] The purpose of the embodiments of the present invention is achieved by the following technical solutions:

[0008] To solve the above technical problems, in the first aspect, the embodiments of the present invention provide a heating system, including:

[0009] A power distribution module, including: an inverter and its wiring, and the inverter is used to control the motor and convert the AC mains into DC power;

[0010] A heating control circuit, whose input terminal is connected to the output terminals of the power distribution module and the temperature control module, and whose output terminal is connected to the control terminal of the heating coil, is used to control the heating temperature of the heating coil according to a control signal;

[0011] The temperature control module is used to output a temperature control signal;

[0012] The heating coil serves as the final control object of the heating system, and its input terminal is connected to the output terminal of the heating control circuit.

[0013] In some embodiments, the frequency converter included in the power distribution module is provided with a DC positive output terminal, a DC negative output terminal, and three-phase input terminals, and the three-phase input terminals are respectively connected to the three-phase live wires of the R phase, S phase, and T phase of the power grid;

[0014] The power distribution module further includes a neutral line;

[0015] The heating control circuit includes:

[0016] A first voltage-dividing switch circuit, whose power input terminal is connected to the DC positive output terminal of the frequency converter and the neutral line,

[0017] A second voltage-dividing switch circuit, whose power input terminal is connected to the neutral line and the DC negative output terminal of the frequency converter.

[0018] In some embodiments, the heating control terminal circuit further includes an overcurrent protection circuit, whose input terminal is connected to the output terminals of the first voltage-dividing switch circuit and the second voltage-dividing switch circuit, and whose output terminal is connected to the input terminals of the temperature control module and the drive circuit.

[0019] In some embodiments, the heating control circuit further includes a drive circuit, whose input terminal is connected to the output terminal of the temperature control module, and whose output terminal is connected to the control terminals of the first voltage-dividing switch circuit and the second voltage-dividing switch circuit, and is used to convert the control signal into a drive signal to control the conduction or cut-off of the first voltage-dividing circuit and the second voltage-dividing circuit.

[0020] In some embodiments, each of the first voltage-dividing switch circuit and the second voltage-dividing switch circuit includes three sets of sub-switch circuits with the same structure, where

[0021] The sub-switch circuit of the first voltage-dividing switch circuit includes:

[0022] A first switching transistor, whose gate is connected to the output terminal of the drive circuit, whose collector is connected to the input terminal of the heating coil, and whose emitter is connected to the neutral line,

[0023] The first freewheeling diode, its negative electrode is connected to the positive output terminal of the direct current of the frequency converter, and its positive electrode is connected to the collector of the first switching tube;

[0024] The sub-switching circuit of the second voltage-dividing switching circuit includes:

[0025] The second switching tube, its gate is connected to the output terminal of the drive circuit, its collector is connected to the input terminal of the heating coil, and its emitter is connected to the negative output terminal of the direct current of the frequency converter,

[0026] The second freewheeling diode, its negative electrode is connected to the neutral line, and its positive electrode is connected to the collector of the second switching tube.

[0027] In some embodiments, the first switching tube and the second switching tube are insulated gate bipolar transistors.

[0028] In some embodiments, the first freewheeling diode and the second freewheeling diode are fast recovery diodes or Schottky diodes.

[0029] In some embodiments, there are six groups of the heating coils,

[0030] The overcurrent protection circuit includes six groups of sub-protection circuits with the same structure. The input terminals of each sub-protection circuit are respectively connected to the output terminal of the sub-switching circuit, and the output terminals are respectively connected to the drive circuit of each group of the heating control circuit and the temperature control module.

[0031] The sub-protection circuit includes:

[0032] A current sensor or a current detection chip, its input terminal is connected to the output terminal of the sub-switching circuit, and its output terminal is connected to the drive circuit of the heating control circuit and the temperature control module.

[0033] In some embodiments, the drive circuit includes six groups of sub-drive circuits with the same structure. The input terminals of each sub-drive circuit are respectively connected to the output terminal of the temperature control module, and the output terminals are respectively connected to the control terminals of each sub-switching circuit,

[0034] The sub-drive circuit includes:

[0035] An optocoupler, its input terminal is connected to the output terminal of the temperature control module;

[0036] A zener diode, connected to the output terminal of the optocoupler, and its output terminal is connected to the control terminal of the sub-switching circuit.

[0037] In some embodiments, the heating system further includes:

[0038] The breaker circuit includes six groups of dual-channel breakers, whose input ends are respectively connected to the output end of the sub-switching circuit, and the output ends are respectively connected to the heating coil.

[0039] To solve the above technical problems, in a second aspect, an injection molding machine provided in an embodiment of the present invention is characterized by including the heating system as described in the first aspect above.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: Different from the prior art, an embodiment of the present invention provides a heating system that can be applied to an injection molding machine. The system includes a power distribution module, a heating coil, a temperature control module, and a heating control circuit. Among them, the power distribution module borrows the function of the frequency converter to convert AC mains into DC power output. The output end of the power distribution module is connected to the input end of the heating control circuit, and the output end of the temperature control module is also connected to the input end of the heating control circuit. The heating control circuit is used to control the heating temperature of the heating coil according to the control signal of the temperature control module. The output end of the heating control circuit is connected to the heating coil. At the same time, in an embodiment of the present invention, the heating coil is used as the braking unit of the frequency converter, and the heating coil can directly draw power from the DC of the frequency converter, thereby greatly increasing the overall power consumption efficiency of the injection molding machine, reducing system losses, and lowering equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In one or more embodiments, exemplary illustrations are provided through the pictures in the corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements / modules with the same reference numerals in the drawings represent similar elements / modules. Unless otherwise stated, the drawings in the drawings do not constitute a scale limitation.

[0042] Figure 1 is a schematic diagram of one application environment of the heating system provided in an embodiment of the present invention;

[0043] Figure 2 is a structural block diagram of a heating system provided in Embodiment 1 of the present invention;

[0044] Figure 3 is a structural block diagram of another heating system provided in Embodiment 1 of the present invention;

[0045] Figure 4 is a structural schematic diagram of a first voltage-dividing switch circuit and a second voltage-dividing switch circuit provided in Embodiment 1 of the present invention;

[0046] Figure 5 is a structural schematic diagram of a sub-protection circuit of an overcurrent protection circuit provided in Embodiment 1 of the present invention;

[0047] Figure 6 is a structural schematic diagram of a sub-driving circuit of a driving circuit provided in Embodiment 1 of the present invention. Detailed Implementation Modes

[0048] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made. These all fall within the protection scope of the present invention.

[0049] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] It should be noted that if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present application. In addition, although the functional modules are divided in the device schematic diagram, in some cases, it can be different from the module division in the device. In addition, the terms "first", "second", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects. It should be noted that when an element is expressed as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween.

[0051] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in this specification in the description of the present invention are only for the purpose of describing specific implementation modes and are not used to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0052] In addition, the technical features involved in the various implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] Currently, the heating coils in the heating system of an injection molding machine usually need to draw power from the AC mains through a rectifier, and the servo motor added during the servo transformation of the injection molding machine itself needs to be connected to a braking resistor when braking. In order to solve the problems of the complex power supply circuit of the heating coils in the current injection molding machine and the waste of braking energy on the braking resistor, the embodiments of the present invention provide a heating system that can be applied to an injection molding machine. This system can directly use the braking energy in the servo system for the heating system, greatly improving the overall power consumption efficiency of the injection molding machine.

[0054] Figure 1Schematic diagram of one application environment of the heating system provided by the embodiment of the present invention. In this application environment, it includes: an injection molding machine 10, and the injection molding machine 10 includes a heating system 100 provided by the embodiment of the present invention. The heating system 100 can be the following specific embodiment, that is, the heating system 100 provided in Embodiment 1. The heating system 100 can act on the heating coil with the braking energy generated in the servo system through a frequency converter, thereby improving energy utilization efficiency, reducing system heat generation, saving energy and protecting the environment. At the same time, a temperature control module and a heating control circuit are also provided in the system to control the heating temperature of the heating coil to ensure that the heating system 100 can operate normally and safely.

[0055] Further, since currently in the heating system 100, mainly solid-state relays or contactors are used as switching devices, and the protection mainly relies on circuit breakers. Once a short circuit or other faults occur in the coil, the load is disconnected through the overload of the circuit breaker, and the operator judges the faulty circuit according to the state of the circuit breaker and performs maintenance work such as replacing the coil. Such protection devices have a relatively long response time and are prone to burning out the switching devices. Therefore, further, the embodiment of the present invention can also improve the circuit design and the devices used in the circuits where the switching devices and the protection devices are located to solve the above problems.

[0056] Specifically, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0057] Embodiment 1

[0058] The embodiment of the present invention provides a heating system. Please refer to Figure 2 , which shows a structural block diagram of a heating system provided by the embodiment of the present invention. The heating system 100 can be applied in the injection molding machine 10 as described above. The heating system 100 includes: a power distribution module 110, a heating coil 120, a temperature control module 130, and a heating control circuit 140. Among them,

[0059] The power distribution module 110 includes: a frequency converter 111 and its wiring. The frequency converter 111 is used to control the motor and convert AC mains into DC power. Its input end is used to input AC mains, and its output end is used to output DC power. The power distribution module 110 can be a module that supplies power to each system in the above-mentioned injection molding machine 10. Specifically, it can be a module that supplies power to at least the heating coil 120 and the servo system in the injection molding machine 10.

[0060] The heating coil 120, as the final control object of the heating system, has its input end connected to the output end of the heating control circuit 140. The heating coil 120 is used to provide heat energy for the injection molding machine 10 to heat and melt the plastic. The heating coil 120 is preferably a coil with high heat conversion efficiency.

[0061] The temperature control module 130 is used to output a temperature control signal; the temperature control module 130 is a module provided with a chip, which can output a control signal for adjusting the heating temperature of the heating coil 120 according to the current heating situation of the injection molding machine 10 and the user's requirements. Specifically, it can be hardware-controlled through circuit design, or the temperature control module 130 can also be a thermostat, which can input software algorithms into a controller and a processor for software control, or it can also be a combination of the hardware control and the software control.

[0062] The heating control circuit 140 has its input end connected to the power distribution module 110 and the output end of the temperature control module 130, and its output end connected to the control end of the heating coil 120, and is used to control the heating temperature of the heating coil 120 according to the control signal. The heating control circuit 140 is a hardware design module that can directly control the heating temperature of the heating coil 120.

[0063] Furthermore, the heating control circuit 140 may also have an overcurrent protection function, and the heating control circuit 140 may also include a driving circuit 144 and an overcurrent protection circuit 143 as described below.

[0064] In the embodiment of the present invention, the heating coil 120 is used as a braking unit of the frequency converter 111, the braking resistor is omitted, and the heating coil 120 can directly draw power from the direct current of the frequency converter 111 and convert electrical energy into heat energy. At the same time, the actual heat output of the heating coil 120 can also be controlled through the temperature control module 130 and the heating control circuit 140. Specifically, the heating temperature of the heating coil 120 is controlled. The heating system 100 provided by the embodiment of the present invention can greatly increase the overall power consumption efficiency of the injection molding machine, reduce system losses, lower equipment costs, and is economical and environmentally friendly.

[0065] In some embodiments, please refer to Figure 3 , which shows a structural block diagram of another heating system provided by the embodiment of the present invention. As Figure 3 shown, the power distribution module 110 includes a frequency converter 111 provided with a direct current positive output terminal DC+, a direct current negative output terminal DC-, and three-phase incoming line terminals, and the three-phase incoming line terminals are respectively connected to the three-phase live wires of the R phase, S phase, and T phase of the power grid; the power distribution module 110 further includes a neutral line N;

[0066] The heating control circuit 140 includes: a first voltage dividing switch circuit 141, whose power input end is connected to the direct current positive output terminal DC+ of the frequency converter 111 and the neutral line N; a second voltage dividing switch circuit 142, whose power input end is connected to the neutral line N and the direct current negative output terminal DC- of the frequency converter 111.

[0067] In the embodiment of the present invention, since the input end of the frequency converter 111 receives 380V AC mains power, it can only rectify the 380V AC mains power and output 380V DC power. However, the heating coils commonly used in the injection molding machines 10 on the market currently are basically of the type with 220V input. The output voltage of the frequency converter 111 exceeds the withstand voltage of the current heating coils. Therefore, in the embodiment of the present invention, a neutral line N is introduced into the power distribution module 110. The potential of the neutral line N is at the midpoint between the DC positive output terminal DC+ and the DC negative output terminal DC- of the direct current. Thus, after dividing the DC bus voltage output by the frequency converter 111 into two substantially equal voltages through the DC positive output terminal DC+ of the frequency converter 111, the DC negative output terminal DC- of the frequency converter 111, and the neutral line N, they are respectively applied to the first voltage-dividing switch circuit 141 and the second voltage-dividing switch circuit 142, so as to provide appropriate voltages for the heating coils 120 respectively connected to the output terminals of the first voltage-dividing switch circuit 141 and the second voltage-dividing switch circuit 142.

[0068] Specifically, please refer to Figure 4 together, which shows the structures of a first voltage-dividing switch circuit and a second voltage-dividing switch circuit provided by the embodiment of the present invention. As Figure 4 shown, each of the first voltage-dividing switch circuit 141 and the second voltage-dividing switch circuit 142 includes three sets of sub-switch circuits with the same structure. Among them,

[0069] The sub-switch circuit 141a of the first voltage-dividing switch circuit 141 includes: a first switching transistor Q1, whose gate is connected to the output terminal of the following driving circuit 144, whose collector is connected to the input terminal of the heating coil 120, and whose emitter is connected to the neutral line N; a first freewheeling diode D7, whose cathode is connected to the DC positive output terminal DC+ of the frequency converter 111, and whose anode is connected to the collector of the first switching transistor Q1.

[0070] The sub-switch circuit 142a of the second voltage-dividing switch circuit 142 includes: a second switching transistor Q2, whose gate is connected to the output terminal of the following driving circuit 144, whose collector is connected to the input terminal of the heating coil 120, and whose emitter is connected to the DC negative output terminal DC- of the frequency converter 111; a second freewheeling diode D10, whose cathode is connected to the neutral line N, and whose anode is connected to the collector of the second switching transistor Q2; a second freewheeling diode D4, whose anode is connected to the emitter of the second switching transistor Q2, and whose cathode is connected to the collector of the second switching transistor Q2.

[0071] Among them, the first switching transistor Q1 and the second switching transistor Q2 are insulated gate bipolar transistors. In the embodiment of the present invention, the first switching transistor Q1 and the second switching transistor Q2 execute whether to supply power to the heating coil 120 according to the control signal sent by the temperature control module 130.

[0072] Among them, the first freewheeling diode D1 and the second freewheeling diode D4 are fast recovery diodes or Schottky diodes. In the embodiment of the present invention, since the heating coil 120 has a certain inductance, it is necessary to add a freewheeling diode to ensure that there is no overvoltage when the switching transistor is turned off.

[0073] In the traditional heating system of an injection molding machine, the switching devices of the heating system usually adopt solid-state relays, contactors or thyristors, which have the characteristic of turning off at the zero crossing and relatively slow response speed. Especially, the contactor may also have adhesion. Usually, when there is overcurrent or overvoltage in the circuit, the switching device may be burned out before it has time to turn off. To solve the problem that the switching device is easily burned out and damaged, in the embodiment of the present invention, six insulated gate bipolar transistors (IGBT transistors) are used as switching transistors to replace the traditional solid-state relay, contactor or thyristor to control six heating coils respectively, which has the characteristics of fast response and timely protection. However, since the insulated gate bipolar transistor (IGBT transistor) requires to work under a DC voltage (the voltage drop Vce between the emitter and the collector), therefore, the switching device in the embodiment of the present invention also utilizes the characteristic that the frequency converter 111 can output DC. On the one hand, the DC power output by the frequency converter 111 can supply power to the heating coil 120, and on the other hand, it provides a relatively high working current voltage for the switching transistor.

[0074] It should be noted that in the embodiment of the present invention, only the structures and connection methods of key devices such as switching transistors and freewheeling diodes in the sub-switching circuit 141a and the sub-switching circuit 142a are described. For the settings, connection methods and models of other devices such as resistors and capacitors in the sub-switching circuit 141a and the sub-switching circuit 142a, reference can be made to the attached Figure 4 shown, but it is not necessary to be limited to the circuit shown in the attached Figure 4 shown, and details are not described here.

[0075] It should also be noted that Figure 4Only the specific circuit structures of the sub-switch circuits 141a and 142a are provided. For the other sub-switch circuits in the first voltage-dividing switch circuit 141 and the other sub-switch circuits in the second voltage-dividing switch circuit 142, since the structures of the other sub-switch circuits in the first voltage-dividing switch circuit 141 are the same as that of the sub-switch circuit 141a, and the structures of the other sub-switch circuits in the second voltage-dividing switch circuit 142 are the same as that of the sub-switch circuit 142a, the only difference lies in the interfaces of the front and rear circuit modules to which the control terminals, input terminals, and output terminals are correspondingly connected (but they are consistent). Therefore, they will not be elaborated here.

[0076] In some embodiments, please continue to refer to Figure 3 , the heating control terminal circuit 140 further includes an overcurrent protection circuit 143, whose input terminal is connected to the output terminals of the first voltage-dividing switch circuit 141 and the second voltage-dividing switch circuit 142, and whose output terminal is connected to the input terminals of the temperature control module 130 and the drive circuit 144.

[0077] Specifically, there are six groups of the heating coils 120 in total. The overcurrent protection circuit 143 includes six groups of sub-protection circuits with the same structure. The input terminals of each sub-protection circuit are respectively connected to the output terminals of the sub-switch circuits, and the output terminals are respectively connected to the drive circuits 144 of each group of the heating control circuits 140 and the temperature control module 130.

[0078] Please refer to Figure 5 together, which shows the structure of a sub-protection circuit of an overcurrent protection circuit provided by an embodiment of the present invention. As Figure 5 shown, the sub-protection circuit 143a includes: a current sensor or a current detection chip U1, whose input terminal is connected to the output terminal of the sub-switch circuit, and whose output terminal is connected to the drive circuit 144 of the heating control circuit 140 and the temperature control module 130; a current-limiting resistor R connected to the control terminal of the current sensor or the current detection chip U1. The current sensor or the current detection chip U1 can immediately cut off the circuit when the current exceeds the set value to achieve reliable protection for the switching device. Specifically, the set value can be set through the configuration of the current-limiting resistor R, and the automatic output of the protection signal to turn off the switching device can be achieved without the participation of devices with computing functions such as a processor.

[0079] In the traditional heating system of an injection molding machine, the protection device of the heating system usually uses a circuit breaker as the protection device, and the response time is relatively long, generally at least 20 ms. The larger the current, the shorter the response time, but the longer the arcing time. If the overcurrent multiple is not large, the response time will be lengthened, which will cause the solid-state relay or contactor, etc., which are used as switching devices, to burn out before the circuit breaker disconnects. In particular, the contactor may stick. In addition, if the overload or short circuit is not cut off in time, it will also damage the entire processing technology and other heating components. In the working conditions of an injection molding machine, the probability of a short circuit in the heating coil is relatively high. Especially, the heating coil of the nozzle often has molten resin overflow, resulting in a short circuit or overload of the heating coil. In addition, other dust, metals, etc. will also cause a short circuit or overload of the heating coil. According to actual statistics, generally on average once every one to two weeks, and even some manufacturers less than two or three days, there will be a short circuit in the heating coil, causing the staff to frequently replace the coil, and even the contactor or solid-state relay, affecting the production downtime and reducing the production efficiency. In order to solve the problem in the traditional injection molding machine that due to the untimely protection of the circuit breaker, the coil and the contactor are burned out, resulting in shutdown for replacement and maintenance, the embodiment of the present invention uses a current sensor or a current detection chip U1 to perform overcurrent or short-circuit protection, which can improve the production efficiency and reduce the maintenance cost.

[0080] It should be noted that the embodiment of the present invention only describes the structures and connection methods of the key devices, namely the current sensor or the current detection chip U1 and the current-limiting resistor R in the sub-protection circuit 143a. For the settings, connection methods and models of other devices such as resistors and capacitors in the sub-protection circuit 143a, reference can be made to the Figure 5 as shown, but it is not necessary to be limited to the circuit Figure 5 shown, and details are not described here.

[0081] It should also be noted that Figure 5 only the specific circuit structure of a sub-protection circuit 143a is provided. For other sub-driving circuits in the overcurrent protection circuit 143, since their structures are the same as that of the sub-protection circuit 143a, the only difference is that the interfaces of the front and rear circuit modules to which the control end, input end and output end are correspondingly connected are different (but consistent). Therefore, details are not described here.

[0082] Furthermore, in the traditional injection molding machine heating circuit, after passing through the contactor / solid-state relay, it also needs to pass through a circuit breaker and then be connected to the heating coil. The circuit breaker plays a role in protection and maintenance. Therefore, in the embodiment of the present invention, the circuit breaker can also be retained for the purpose of equipment maintenance. Once a short circuit occurs in a certain coil, it is required that the whole injection molding machine does not lose power during maintenance. At this time, the circuit breaker can ensure the safe replacement of the heating coil 120 without power loss of the injection molding machine.

[0083] In some embodiments, please continue to refer to Figure 3, the heating control circuit 140 further includes a driving circuit 144, whose input end is connected to the output end of the temperature control module 130, and whose output end is connected to the control ends of the first voltage dividing switch circuit 141 and the second voltage dividing switch circuit 142, and is used to convert the control signal into a driving signal to control the conduction or cut-off of the first voltage dividing circuit 141 and the second voltage dividing circuit 142.

[0084] Specifically, the driving circuit 144 includes six sets of sub-driving circuits with the same structure. The input ends of the sub-driving circuits are respectively connected to the output end of the temperature control module 130, and the output ends are respectively connected to the control ends of the sub-switch circuits.

[0085] Please refer to Figure 6 together, which shows the structure of a sub-driving circuit of a driving circuit provided by an embodiment of the present invention. As Figure 6 shown, the sub-driving circuit 144a includes: an optocoupler U10, whose input end is connected to the output end of the temperature control module 130; a zener diode ZD1, connected to the output end of the optocoupler U10, and whose output end is connected to the control end of the sub-switch circuit.

[0086] Further, the heating system further includes: a circuit breaker circuit, including six sets of dual-channel circuit breakers, whose input ends are respectively connected to the output ends of the sub-switch circuits, and the output ends are respectively connected to the heating coils.

[0087] In the embodiment of the present invention, a general driving optocoupler is used to drive the switching tube to achieve the large-current driving of the switching device and can have a breakdown voltage of 5000V.

[0088] It should be noted that the embodiment of the present invention only describes the structures and connection manners of the key devices, i.e., the optocoupler U10 and the zener diode ZD1, in the sub-driving circuit 144a. For the settings, connection manners and models of other devices such as resistors and capacitors in the sub-driving circuit 144a, reference can be made to the appendix Figure 6 shown, but it is not necessary to be limited to the circuit shown in the appendix Figure 6 shown, and details are not described here.

[0089] It should also be noted that Figure 6 only the specific circuit structure of one sub-driving circuit 144a is provided. For the other sub-driving circuits in the driving circuit 144, since their structures are the same as that of the sub-driving circuit 144a, the only difference lies in the interfaces of the front and rear circuit modules corresponding to the input and output ends being connected differently (but consistently). Therefore, details are not described here.

[0090] An embodiment of the present invention provides a heating system that can be applied in an injection molding machine. The system includes a power distribution module, a heating coil, a temperature control module, and a heating control circuit. Among them, the power distribution module borrows the function of the frequency converter to convert AC mains into DC output. The output end of the power distribution module is connected to the input end of the heating control circuit, and the output end of the temperature control module is also connected to the input end of the heating control circuit. The heating control circuit is used to control the heating temperature of the heating coil according to the control signal of the temperature control module. The output end of the heating control circuit is connected to the heating coil. At the same time, in the embodiment of the present invention, the heating coil is used as the braking unit of the frequency converter, and the heating coil can directly draw power from the DC of the frequency converter, thereby greatly increasing the overall power consumption efficiency of the injection molding machine, reducing system losses, and lowering equipment costs.

[0091] It should be noted that the device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. There are many other changes in different aspects of the present invention as described above, and they are not provided in detail for the sake of brevity. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heating system, characterized in that, Comprising: A power distribution module, including: an inverter and its wiring, where the inverter is used to control a motor and convert AC mains power into DC power; A heating control circuit, whose input end is connected to the output ends of the power distribution module and the temperature control module, and whose output end is connected to the control end of a heating coil, for controlling the heating temperature of the heating coil according to a control signal. Among them, there are six groups of the heating coils in total; The temperature control module is used to output a temperature control signal; The heating coil is the final control object of the heating system, and its input end is connected to the output end of the heating control circuit; Among them, the inverter included in the power distribution module is provided with a DC positive output end, a DC negative output end, and three-phase incoming line ends, and the three-phase incoming line ends are respectively connected to the three-phase live wires of R phase, S phase, and T phase of the power grid; The power distribution module further includes a neutral line; The heating control circuit includes: A first voltage dividing switch circuit, whose power input end is connected to the DC positive output end of the inverter and the neutral line; A second voltage dividing switch circuit, whose power input end is connected to the neutral line and the DC negative output end of the inverter; Among them, each of the first voltage dividing switch circuit and the second voltage dividing switch circuit includes three groups of sub-switch circuits with the same structure, and each sub-switch circuit includes a switching tube, and the switching tube is correspondingly connected to the heating coil.

2. The heating system according to claim 1, characterized in that The heating control terminal circuit further includes an overcurrent protection circuit, whose input end is connected to the output ends of the first voltage dividing switch circuit and the second voltage dividing switch circuit, and whose output end is connected to the input ends of the temperature control module and the drive circuit.

3. The heating system according to claim 2, characterized in that The heating control circuit further includes a drive circuit, whose input end is connected to the output end of the temperature control module, and whose output end is connected to the control ends of the first voltage dividing switch circuit and the second voltage dividing switch circuit, for converting the control signal into a drive signal and then controlling the conduction or cutoff of the first voltage dividing circuit and the second voltage dividing circuit.

4. The heating system according to claim 3, characterized in that The sub-switch circuit of the first voltage dividing switch circuit includes: A first switching tube, whose gate is connected to the output end of the drive circuit, whose collector is connected to the input end of the heating coil, and whose emitter is connected to the neutral line; A first freewheeling diode, whose cathode is connected to the DC positive output end of the inverter, and whose anode is connected to the collector of the first switching tube; The sub-switch circuit of the second voltage dividing switch circuit includes: A second switching tube, whose gate is connected to the output end of the drive circuit, whose collector is connected to the input end of the heating coil, and whose emitter is connected to the DC negative output end of the inverter; A second freewheeling diode, whose cathode is connected to the neutral line, and whose anode is connected to the collector of the second switching tube.

5. The heating system according to claim 4, characterized in that The first switching tube and the second switching tube are insulated gate bipolar transistors.

6. The heating system according to claim 5, characterized in that The first freewheeling diode and the second freewheeling diode are fast recovery diodes or Schottky diodes.

7. The heating system according to any one of claims 4-6, characterized in that the overcurrent protection circuit includes six sub-protection circuits with the same structure, the input ends of the sub-protection circuits are respectively connected to the output ends of the sub-switching circuits, and the output ends are respectively connected to the driving circuits of each group of the heating control circuits and the temperature control module, the sub-protection circuit includes: a current sensor or a current detection chip, whose input end is connected to the output end of the sub-switching circuit, and whose output end is connected to the driving circuit of the heating control circuit and the temperature control module.

8. The heating system according to claim 7, characterized in that the driving circuit includes six sub-driving circuits with the same structure, the input ends of the sub-driving circuits are respectively connected to the output end of the temperature control module, and the output ends are respectively connected to the control ends of the sub-switching circuits, the sub-driving circuit includes: an optocoupler, whose input end is connected to the output end of the temperature control module; a zener diode, connected to the output end of the optocoupler, and whose output end is connected to the control end of the sub-switching circuit.

9. The heating system according to claim 8, wherein, The heating system further includes: a circuit breaker circuit, including six groups of dual-channel circuit breakers, whose input ends are respectively connected to the output ends of the sub-switching circuits, and whose output ends are respectively connected to the heating coils.

10. An injection molding machine, characterized in that, including the heating system according to any one of claims 1-9 above.

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