Abnormality determination device and hermetic electric compressor

Abstract

The utility model relates to an abnormality judging device which can judge abnormal heating of a motor temperature caused by a fault such as a decrease in the flowability of refrigerant in advance. The abnormality judging device is installed in a compressor container that houses an inverter-controlled motor and a compression mechanism and is filled with refrigerant or the like. The abnormality judging device has: a gas-tight terminal portion having a power terminal and a signal terminal that penetrate a metal substrate; a temperature detecting element; and a signal processing portion. A motor lead wire is connected to a control device via the power terminal, and the signal processing portion is connected to the control device via the signal terminal. The signal processing portion sends an abnormality detection signal when an abnormality occurs.

Description

Technical Field

[0001] This utility model relates to an anomaly detection device for a hermetic electric compressor, and a hermetic electric compressor having an anomaly detection device. Background Technology

[0002] Typically, the hermetic electric compressor used in the refrigeration cycle of air conditioners, refrigerators, etc., has an electric motor and a compression mechanism driven by the motor inside the compressor casing. The compressor is filled with refrigerant, and the electric motor is exposed to the refrigerant within the compressor casing. Under normal operating conditions, the electric motor, which generates heat during operation, is cooled by the refrigerant, thus preventing the motor temperature from exceeding a specified limit.

[0003] In such a hermetic electric compressor, if an abnormal condition occurs, such as blockage in the refrigeration cycle pipes or motor lock-up, significantly reducing or stopping the flow of refrigerant, the cooling efficiency of the refrigerant will decrease. Furthermore, if the hermetic electric compressor continues to operate under such abnormal conditions, excessive current will flow through the motor under increased load. The resulting heat will cause the motor temperature to rise continuously. A high-temperature motor poses a risk of burning out insulation components or causing thermal decomposition of the refrigerant and refrigeration oil, thus reducing the reliability of the compressor and refrigeration cycle. Therefore, to prevent such failures, a protection unit exists that determines the abnormal condition based on the temperature of the motor and refrigerant, and controls operation by stopping power to the motor.

[0004] For example, as a protection unit in the operation control of a hermetic electric compressor, the operating status of the compressor is sometimes determined and operating conditions are changed based on factors such as the temperature of the refrigerant flowing in the pipes and the temperature of the compressor container. In such a protection unit, to quickly detect abnormalities, it is preferable to place the temperature sensor as close as possible to the motor. As one example, a structure is considered in which the temperature sensor is directly mounted on the motor inside the container of the hermetic electric compressor by means of binding or fixing, and the temperature sensor is connected to an airtight terminal on the wall of the compressor container by a wire, and the output of the temperature sensor is led out to the outside of the container through the airtight terminal on the wall of the compressor container.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2015 / 174054;

[0008] Patent Document 2: U.S. Patent Application Publication No. 2005 / 0196285.

[0009] Problems to be solved by utility models

[0010] However, the longer the wire from the temperature sensor to the airtight terminal, the more easily the electromagnetic waves generated by the alternating current flowing in the motor can affect the wire, sometimes causing noise in the temperature sensor's output. Furthermore, the installation of the temperature sensor on the motor and the wiring between the temperature sensor and the airtight terminal are complex, increasing manufacturing time.

[0011] Furthermore, from the perspective of addressing global warming, refrigeration cycles using natural refrigerants with low Global Warming Potential (GWP) and Ozone Depletion Potential (ODP) have been developed as alternatives to Freon gases. Specifically, refrigerants such as propane (R290) and butane (R600a) have been proposed as natural refrigerants. However, these are flammable refrigerants, posing a risk of ignition or fire if the energized parts of the electric motor, which heats up during operation, come into contact with the refrigerant. Therefore, when using flammable natural refrigerants, it is necessary to control the motor temperature to prevent it from exceeding the temperature that could cause ignition or fire. Consequently, a hermetic electric compressor protection unit is needed that can quickly stop energizing the motor in the event of an abnormally high-temperature motor. Utility Model Content

[0012] This invention was made in view of the above circumstances, and its purpose is to provide an anomaly detection device that can detect abnormal heating of the motor temperature caused by faults such as reduced refrigerant flowability in advance, and can be manufactured through simple operations, as well as a hermetically sealed electric compressor having the anomaly detection device.

[0013] Solution for solving the problem

[0014] The anomaly detection device (5) of the embodiment is installed in a hermetically sealed electric compressor (1) and includes: an inverter-controlled motor (3); a compression mechanism (4) driven by the motor; and a compressor container (2) which houses the motor and the compression mechanism and is filled with refrigerant and refrigeration oil. The anomaly detection device (5) has an airtight terminal section (20) and a functional section (30). The airtight terminal section has a metal substrate (21), a power terminal (22), and a signal terminal (23). The power terminal and the signal terminal are disposed through the metal substrate and are fixed to the metal substrate in an airtight and electrically insulating state using an electrically insulating filling material (24). The power terminal and the signal terminal are disposed through the compressor container. The functional unit is disposed inside the compressor container and includes: a temperature detection element (331, 332), a signal processing unit (34) for judging abnormalities based on the output of the temperature detection element, and a resin housing (31) on which the temperature detection element and the signal processing unit are disposed. The power supply terminal is electrically connected inside the compressor container to a motor wire (3a) leading from the motor, and is connected outside the compressor container to a control device (10) for controlling the motor. The signal terminal is connected inside the compressor container to the signal processing unit, and is connected outside the compressor container to the control device. The signal processing unit sends an abnormality detection signal to the control device when an abnormality is judged.

[0015] The hermetic electric compressor (1) of the embodiment includes: an electric motor (3) controlled by an inverter; a compression mechanism (4) driven by the electric motor; a compressor container (2) which houses the electric motor and the compression mechanism and is filled with refrigerant and refrigeration oil; and the above-mentioned abnormality detection device (5) installed in the compressor container. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view schematically illustrating an example of a hermetically sealed electric compressor having an anomaly detection device according to one embodiment.

[0017] Figure 2 This is a diagram showing an example of an electrical connection method for a hermetically sealed electric compressor having an anomaly detection device according to one embodiment.

[0018] Figure 3 This is a top view showing an example of the airtight terminal portion of an anomaly detection device according to one embodiment.

[0019] Figure 4 This is a top view showing an example of the functional part of an anomaly detection device according to one embodiment.

[0020] Figure 5 This is a diagram showing the state after the airtight terminal and the functional part are assembled, and it is along one embodiment of the anomaly detection device. Figure 3 and Figure 4 The cross-sectional view is shown along line X5-X5.

[0021] Figure 6 This is a diagram showing the state of an anomaly detection device according to one embodiment, before the airtight terminal part and the functional part are assembled, and it is along... Figure 3 and Figure 4 The cross-sectional view shown is X5-X5.

[0022] Figure 7 This is a diagram showing the airtight terminal portion of an anomaly detection device according to one embodiment, and it is along... Figure 3 The cross-sectional view shown by line X7-X7.

[0023] Figure 8 This is a diagram showing the functional section of an anomaly detection device according to one embodiment, and it is... Figure 4 The image viewed in the X8 direction of the arrow.

[0024] Figure 9 This is a diagram showing the functional section of an anomaly detection device according to one embodiment, and it is along... Figure 4 The cross-sectional view is shown along line X9-X9.

[0025] Figure 10 This is a cross-sectional view showing an example of a heating element in the functional part of an abnormality detection device according to one embodiment. Detailed Implementation

[0026] Hereinafter, with reference to the accompanying drawings, an example of an anomaly detection device according to one embodiment, and an example of a hermetically sealed electric compressor having the anomaly detection device, will be described. Figure 1 As shown, the hermetic electric compressor 1 has a compressor container 2, an electric motor 3, a compression mechanism 4, and an abnormality detection device 5.

[0027] The compressor container 2 is an airtight and pressure-resistant container that forms the outer shell of the hermetic electric compressor 1. The motor 3 and the compression mechanism 4 are both housed within the compressor container 2. That is, the compressor container 2 houses the motor 3 and the compression mechanism 4, and is filled with refrigerant and refrigeration oil. The motor 3 is connected to an external control device 10 and is controlled by the control device 10 via inverter operation. The control device 10 controls the current supplied to the motor 3 according to operating conditions. The compression mechanism 4 has the function of compressing and discharging refrigerant by being driven by the motor 3. The compression mechanism 4 can be, for example, a rotary vane type or a scroll type. Three motor wires 3a are led out from the motor 3.

[0028] like Figures 2 to 5 As shown, the anomaly detection device 5 includes an airtight terminal section 20 and a functional section 30, and is installed in the compressor container 2. The airtight terminal section 20 has a metal substrate 21, three power supply terminals 22, and multiple signal terminals 23. The metal substrate 21 is made of materials such as steel or stainless steel and is airtightly welded and fixed to the compressor container 2. The power supply terminals 22 and the signal terminals 23 have the function of electrically connecting the interior of the compressor container 2 to the outside.

[0029] The power supply terminal 22 is formed, for example, in the shape of a cylindrical rod and is disposed through a hole formed in the metal substrate 21. The power supply terminal 22 is made of metal materials such as iron-nickel alloy, ferritic stainless steel, or Kovar alloy. The hermetic terminal section 20 has, for example, three signal terminals 23. The signal terminals 23 are formed of cylindrical rods and are disposed through a hole formed in the metal substrate 21. The signal terminals 23 are the same as the power supply terminals 22, and are made of metal materials such as iron-nickel alloy, ferritic stainless steel, or Kovar alloy.

[0030] The power supply terminal 22 and the signal terminal 23 are filled with an electrically insulating filler material 24 between themselves and the metal substrate 21. The electrically insulating filler material 24 is made of an electrically insulating component such as glass. As a result, the power supply terminal 22 and the signal terminal 23 are kept airtight with the metal substrate 21 in an electrically insulating state.

[0031] The functional unit 30 includes a housing 31, multiple temperature sensing elements 331 and 332, a signal processing unit 34, and a heating element 40. Based on the detection results of the temperature sensing elements 331 and 332, the functional unit 30 determines whether there is an abnormality and outputs the result. For example, if the internal state of the compressor container 2 is normal, based on the output of the temperature sensing elements 331 and 332, the functional unit 30 outputs a normal signal. Furthermore, the functional unit 30 determines abnormalities such as rapid temperature changes inside the compressor container 2 or values ​​exceeding a specified limit, and outputs an abnormality detection signal. The functional unit 30 has the function of electrically connecting the motor wire 3a leading from the motor 3 to the power supply terminal 22 of the airtight terminal unit 20.

[0032] The housing 31 is made of resin and serves as a base for mounting temperature sensing elements 331 and 332, the signal processing unit 34, and the heating element 40. The housing 31 uses resin materials with excellent electrical insulation properties, such as polyamide (PA), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and liquid crystal polymer (LCP), which have excellent durability against refrigerants and refrigeration oils.

[0033] Temperature sensing elements 331 and 332 and signal processing unit 34 are mounted on housing 31, either directly or via a circuit board (not shown). The circuit board is a printed circuit board made of glass epoxy resin or the like, on which the temperature sensing elements 331 and 332 and signal processing unit 34 are mounted. Temperature sensing elements 331 and 332 are components that change their output according to the ambient temperature; for example, thermistors, resistance temperature detectors, and other semiconductor sensors can be used. Temperature sensing elements 331 and 332 detect the temperature of a specified location within the compressor container 2.

[0034] Two temperature sensing elements 331 and 332 detect the temperature at different locations within the compressor container 2. In the following description, when distinguishing between the two temperature sensing elements 331 and 332, one may be referred to as the first temperature sensing element 331, and the other as the second temperature sensing element 332. The first temperature sensing element 331 is positioned in contact with the device container 41 of the heating element 40 and primarily detects the temperature of the heating element 40. The second temperature sensing element 332 is positioned away from the device container 41 of the heating element 40 and primarily detects the temperature of the refrigerant within the compressor container 2.

[0035] The signal processing unit 34 can be configured, for example, as a microcontroller. The signal processing unit 34 is electrically connected to temperature sensing elements 331 and 332 via patterned wiring (not shown) provided on a circuit board, and processes the outputs of the temperature sensing elements 331 and 332 to measure the temperature. Based on the outputs of the temperature sensing elements 331 and 332, the signal processing unit 34 determines an abnormality in the hermetic electric compressor 1 and outputs its determination result to the control device 10 outside the compressor container 2.

[0036] The heating element 40 is exposed to the refrigerant within the compressor container 2. The heating element 40 generates heat due to the current flowing in the motor 3. The heating element 40 is housed in the casing 31. Figure 10 As shown, the heating element 40 has a device container 41, a pin 42, and a heating element 43. The heating element 40 is disposed in the housing 31 such that a portion of the device container 41 is exposed within the compressor container 2, that is, exposed to the refrigerant flowing within the compressor container 2.

[0037] The device container 41 is a container made of a metal with high thermal conductivity, such as stainless steel, and is sealed in an airtight state. The device container 41 can be, for example, a structure composed of an open container-shaped container part 411 and a cover plate 412 that closes the open end of the container part 411. Both the container part 411 and the cover plate 412 are made of metal, and the cover plate 412 is welded and fixed to the container part 411.

[0038] The pin 42 is fixed to the device container 41 in an airtight and electrically insulating state by an electrically insulating filler material 44. In this case, the pin 42 passes through a hole formed in the cover plate 412. Moreover, an electrically insulating filler material 44, such as glass, is filled between the pin 42 and the cover plate 412. Thus, the pin 42 is fixed relative to the cover plate 412 in an airtight and electrically insulating state, and electrically connects the interior of the device container 41 to the outside.

[0039] The heating element 43 is housed inside the device container 41 and is made of a resistive material. The heating element 43 is constructed by adjusting the width and length of a metal plate, such as an iron-nickel alloy, copper-nickel alloy, nickel-chromium alloy, or stainless steel, to obtain a specified resistance value. The heating element 43 is connected in series between the power supply terminal 22 and the motor lead 3a, and heats up due to the current flowing in the motor 3, thus heating the device container 41.

[0040] The pin 42 is configured as a cylindrical rod, for example, and is provided through the device container 41. The pin 42 is made of metal materials such as iron-nickel alloy, ferritic stainless steel, or Kovar alloy. Inside the device container 41, one end of the heating element 43 is fixed to the pin 42, and the other end is fixed to the device container 41. In this case, the other end of the heating element 43 is fixed to the cover plate 412.

[0041] One of the device container 41 or pin 42 is directly or indirectly connected to the power supply terminal 22. The other is directly or indirectly connected to one of the three motor wires 3a. Thus, the heating element 43 is connected in series between the power supply terminal 22 and the motor wire 3a.

[0042] Specifically, the functional unit 30 also includes a heating element connection part 37, three power supply terminal connection parts 35, and multiple, in this case, three signal terminal connection parts 36. The power supply terminal connection parts 35, signal terminal connection parts 36, and heating element connection parts 37 are all made of metal terminals and are installed in the housing 31, allowing them to be integrally integrated with the housing 31. The power supply terminal connection parts 35 and signal terminal connection parts 36 are made of metal materials such as phosphor bronze, brass, or Corson alloys that have been tin-plated or Ni-plated.

[0043] The heating element connection 37 can be made of a plate-shaped electrode terminal, which is made of brass or steel plate that has been tin-plated or Ni-plated. One side of the heating element connection 37 is connected to the heating element 43 via the cover plate 412 of the heating device 40, and the other side is connected to the end of the motor wire 3a.

[0044] like Figure 2As shown, the end of the motor wire 3a is directly or indirectly connected to the power supply terminal connection portion 35. The three power supply terminal connection portions 35 correspond to the three power supply terminals 22 respectively. The power supply terminal connection portions 35 electrically connect the motor wire 3a to the power supply terminal 22 by fitting into the power supply terminal 22, and mechanically connect the power supply terminal connection portion 35 to the power supply terminal 22. Two of the three motor wires 3a are directly connected to the power supply terminal connection portions 35. Furthermore, one of the three motor wires 3a is indirectly connected to the power supply terminal connection portion 35 via the heating element connection portion 37 and the heating element 43.

[0045] The signal processing unit 34 is connected to the signal terminal connection portion 36. Multiple signal terminal connection portions 36, in this case three, correspond to three signal terminals 23 respectively. The signal terminal connection portion 36 electrically connects the signal processing unit 34 to the signal terminals 23 by engaging with them, and also mechanically connects the signal terminal connection portion 36 to the signal terminals 23. In this structure, by engaging the power supply terminal 22 with the power supply terminal connection portion 35 and engaging the signal terminals 23 with the signal terminal connection portion 36, the hermetic terminal portion 20 and the functional unit 30 can be electrically connected simultaneously while being mechanically connected.

[0046] Here, the outputs of temperature sensing elements 331 and 332 are input to the signal processing unit 34, where temperature and anomaly detection are processed. Furthermore, the longer the wires between the temperature sensing elements 331 and 332 and the signal processing unit 34, which processes the outputs of the temperature sensing elements 331 and 332, the more easily noise, such as electromagnetic waves, is introduced into the signal. Since noise is a significant cause of reduced sensitivity and misjudgment in temperature detection, it is necessary to reduce noise. Shortening the wires is considered as a way to reduce noise. However, using short wires to connect the airtight terminal 20 to the temperature sensing elements 331 and 332 would complicate the wiring process and reduce productivity.

[0047] Therefore, in the anomaly detection device 5, temperature sensing elements 331 and 332 and signal processing unit 34 are mounted, for example, on a circuit board (not shown), and the temperature sensing elements 331 and 332 are electrically connected to the signal processing unit 34 using patterned wiring provided on the circuit board. This minimizes the electrical wiring between the temperature sensing elements 331 and 332 and the signal processing unit 34, suppressing noise interference. Furthermore, by using patterned wiring provided on a circuit board (not shown) to connect the temperature sensing elements 331 and 332 to the signal processing unit 34, the operator is no longer required to handle short wires to connect the temperature sensing elements 331 and 332 to the signal processing unit 34, reducing complex wiring operations and improving productivity.

[0048] Furthermore, although analog signals are output from temperature sensing elements 331 and 332, the signal processing unit 34 does not output analog signals, but instead outputs digital signals for serial communication. Compared to analog signals, digital signals for serial communication are less susceptible to electromagnetic waves generated by the current flowing in the motor 3.

[0049] Thus, in the anomaly detection device 5, by arranging the temperature sensing elements 331 and 332 and the signal processing unit 34 on the circuit board, and by minimizing the wiring of the analog signal connecting the temperature sensing elements 331 and 332 to the signal processing unit 34, the impact of noise can be reduced. Furthermore, by arranging the circuit board on which the temperature sensing elements 331, 332, and the signal processing unit 34 are mounted in the housing 31, the temperature sensing elements 331, 332, and the signal processing unit 34 can be processed as a single unit. Moreover, by embedding the power supply terminal 22 and the signal terminal 23 into the power supply terminal connection portion 35 and the signal terminal connection portion 36 respectively, the airtight terminal portion 20 and the functional unit 30 can be mechanically connected and electrically connected simultaneously. Therefore, the operator can easily install the functional unit 30 on the airtight terminal portion 20.

[0050] Furthermore, the anomaly detection device 5 is capable of serial communication between the signal processing unit 34 and the control device 10. Therefore, compared to a structure that transmits analog signals, the anomaly detection device 5 can improve the reliability of the signal transmitting the detection result to the control device 10.

[0051] Since the signal processing unit 34 requires multiple power supply wires and signal wires, the hermetic terminal section 20 needs to be equipped with multiple signal terminals 23. However, in order to prevent the hermetic terminal section 20 from becoming too large, it is preferable to minimize the number of signal terminals 23. However, communication between the signal processing unit 34 and the control device 10 can be achieved using a communication method such as UART (Universal Asynchronous Receiver / Transmitter). By using this communication method, the signal processing unit 34 can operate using only three wires: a power supply wire, a communication wire, and a ground wire.

[0052] In addition, if the communication method of the control device 10 is different from that of the abnormal judgment device 5, an additional signal conversion circuit can be installed on the outside of the compressor container 2, or communication can be carried out using a communication cable with the function of converting the communication method.

[0053] Furthermore, the hermetic terminal section 20 has three power supply terminals 22 and multiple signal terminals 23. For example... Figure 3 As shown, each signal terminal 23 is located in the area outside the circle that connects the centers of the three power supply terminals 22.

[0054] Therefore, since the configuration of the power supply terminal 22 is different from that of the signal terminal 23, they can be installed in their respective positions. Thus, for the airtight terminal section 20 and the functional section 30, by aligning the positions of the power supply terminal 22 and the power supply terminal connection section 35, and the signal terminal 23 and the signal terminal connection section 36, and for example by pressing the functional section 30 towards the airtight terminal section 20, the power supply terminal 22 and the power supply terminal connection section 35 are electrically and mechanically connected, and the signal terminal 23 and the signal terminal connection section 36 are also electrically and mechanically connected. This allows for easy and accurate installation and wiring. As a result, a fault detection device 5 with excellent productivity and high reliability, and a hermetic electric compressor 1 equipped with this fault detection device 5, can be realized.

[0055] like Figure 5 As shown, the outer diameter D2 of the signal terminal 23 is set to be smaller than the outer diameter D1 of the power terminal 22. For example, if the outer diameter D1 of the power terminal 22 is set to about 3 mm, the outer diameter D2 of the signal terminal 23 is set to about 2 mm. This allows the signal terminal 23 to be placed within the defined space of the hermetic terminal section 20. However, when the functional unit 30 is installed in the hermetic terminal section 20, the signal terminal 23, with its smaller outer diameter, is weaker than the power terminal 22, which has a larger outer diameter, and therefore poses a risk of deformation when in contact with the housing 31 or the like.

[0056] Therefore, as Figure 6 As shown, the length L2 of the portion of the signal terminal 23 protruding from the metal substrate 21 into the compressor housing 2 is set to be shorter than the length L1 of the portion of the power terminal 22 protruding from the metal substrate 21 into the compressor housing 2. Furthermore, as... Figure 5 As shown, the axial length W2 of the signal terminal 23 that contacts the signal terminal connector 36 is set to be shorter than the axial length W1 of the power terminal 22 that contacts the power terminal connector 35. That is, the length W2 of the signal terminal 23 when engaged with the signal terminal connector 36 is set to be shorter than the length W1 of the power terminal 22 when engaged with the power terminal connector 35.

[0057] Therefore, when the functional unit 30 is installed on the airtight terminal section 20, if the functional unit 30 and the airtight terminal section 20 are placed close together, the strong power terminal 22 will contact and engage with the power terminal connection section 35 before the weak signal terminal 23 engages with the signal terminal connection section 36. Thus, by engaging the power terminal 22 with the power terminal connection section 35 before the signal terminal 23 engages with the signal terminal connection section 36, the signal terminal 23 is guided to the correct position for engaging with the signal terminal connection section 36. Therefore, the signal terminal 23 can be connected to the signal terminal connection section 36 without applying excessive force to the weak signal terminal 23. As a result, when the functional unit 30 is installed on the airtight terminal section 20, poor contact caused by deformation of the signal terminal 23 can be suppressed, and an anomaly detection device 5 that can be installed with simple operations and has excellent productivity, as well as a hermetic electric compressor 1 equipped with this anomaly detection device 5, are realized.

[0058] Here, the heating element 40 is exposed to the refrigerant within the compressor container 2. That is, the heating element 40 is positioned where it is exposed to the flow of refrigerant within the compressor container 2 when the refrigerant flow is normal. When the motor 3 is operating normally, the refrigerant also flows normally, and the heating element 40 is cooled by the refrigerant flow.

[0059] The functional unit 30 includes: a first temperature sensing element 331 disposed in contact with the device container 41; and a second temperature sensing element 332 disposed away from the device container 41. The signal processing unit 34 is capable of making an anomaly judgment based on the difference between the detected temperature of the first temperature sensing element 331 and the detected temperature of the second temperature sensing element 332.

[0060] For example, if the pipes in the refrigeration cycle are not blocked and the motor 3 is operating normally, the refrigerant in the compressor container 2 also flows normally. In this case, the heating element 40 is also cooled by the refrigerant, so the difference between the detected temperatures of the first temperature sensing element 331 and the second temperature sensing element 332 is small. Conversely, if, for example, an abnormal condition occurs, such as a blockage in the pipes of the refrigeration cycle, a locked motor 3, or a significant reduction or cessation of refrigerant flow in the compressor container 2, the heating element 40 will not be cooled, and its temperature will rise. Therefore, the signal processing unit 34 can, for example, determine that an abnormality has occurred if the detection result of the first temperature sensing element 331 is significantly larger than the detection result of the second temperature sensing element 332 than a predetermined range.

[0061] In this anomaly detection principle, to improve the sensitivity of anomaly detection, it is preferable to increase the difference between the detection temperature of the first temperature detection element 331 and the detection temperature of the second temperature detection element 332. Increasing the resistance value of the heating element 43 and achieving a greater amount of heat generated upon energization is effective in increasing this temperature difference. However, if the resistance value of the heating element 43 is too high, there is a risk that, under operating conditions with high current flow such as when the motor 3 starts, the temperature will rise sharply even for a short time, exceeding the heat resistance temperature of the resin casing 31 before the refrigerant flow stabilizes.

[0062] Therefore, the heating element 40 adopts a structure in which the heating element 43 is housed in a metal device container 41, and the heating element 43 is not in direct contact with the housing 31. Thus, by balancing the cooling effect generated by the refrigerant flow with the delayed temperature rise effect caused by the heat capacity of the device container 41, the device container 41 can suppress instantaneous overheating of the heating element 40 caused by localized heating of the heating element 43 during startup, and by utilizing the excellent thermal conductivity of metal, rapid responsiveness is achieved through heat transfer from the heating element 43 to the device container 41. Furthermore, since the heating element 43 is not in direct contact with the refrigerant, refrigeration oil, etc., even in the event of overcurrent due to power failure, the thermal decomposition caused by direct contact between the refrigerant, refrigeration oil, and the heating element 43 can be effectively suppressed, thereby effectively preventing accidents such as ignition and fire.

[0063] Furthermore, since the heating element 43 is housed within the device container 41, deformation of the heating element 43 caused by exposure to the flow of refrigerant can be prevented. Therefore, in order to obtain the desired resistance value for the heating element 43, a high degree of freedom of design can be adopted for the heating element 43, such as using thin-diameter windings and complex meandering shapes.

[0064] Here, the motor 3 is constructed by winding low-resistance materials such as copper or aluminum onto an iron motor core, resulting in a large mass and overall large heat capacity. Therefore, even if the motor 3 malfunctions, it takes a considerable amount of time for the current flowing through the windings to raise the temperature of the motor 3 to a level sufficient to indicate an abnormality in the refrigerant or compressor container 2. On the other hand, since the heating element 40 is smaller and has a smaller heat capacity than the motor 3, its surface temperature rises before that of the refrigerant or compressor container 2 in abnormal conditions where the refrigerant's flow decreases or stops, reducing cooling efficiency. Consequently, the functional unit 30 can detect the abnormal condition before the motor 3 reaches its heat-resistant temperature and quickly send an abnormality detection signal to the control device 10 via the signal processing unit 34.

[0065] The functional unit 30 includes a circuit board constituting the anomaly detection function, temperature detection elements 331 and 332, a signal processing unit 34, and a heating element 40. Furthermore, to mechanically and electrically connect the signal processing unit 34, the heating element 40, and the hermetic terminal unit 20, the functional unit 30 includes a power supply terminal connection portion 35 and a signal terminal connection portion 36. In other words, the functional unit 30 adopts a structure that integrates the components performing the anomaly detection function with the components performing the connection function to the hermetic terminal unit 20. Therefore, the operator can assemble the anomaly detection device 5 simply by installing the functional unit 30 on the hermetic terminal unit 20 without performing complex wiring work. As a result, a hermetic electric compressor 1 with excellent productivity and high reliability can be provided.

[0066] like Figure 9 As shown, the housing 31 also has a guide portion 311. The guide portion 311 is disposed opposite to the device container 41 and has the function of positioning the first temperature sensing element 331 in contact with the surface of the device container 41. In this case, the first temperature sensing element 331 is disposed between the device container 41 and the guide portion 311, and is positioned by pressing the guide portion 311 against the device container 41.

[0067] In this way, by holding the first temperature sensing element 331 between the guide portion 311 and the device container 41, even if affected by vibrations generated during the operation of the hermetic electric compressor 1 or collisions during assembly, the position of the first temperature sensing element 331 is not easily changed, and a stable position can be maintained. Therefore, the contact state between the first temperature sensing element 331 and the heating element 40 can be stabilized, and the temperature of the heating element 40 can be reliably detected by the first temperature sensing element 331. As a result, the accuracy of determining the operating status can be improved.

[0068] Alternatively, an adhesive or similar material can be provided between the guide portion 311 and the device container 41 to fix the first temperature sensing element 331. Furthermore, the guide portion 311 can be any unit capable of maintaining the position of the first temperature sensing element 331, and can also be a structure such as a spring or other elastic body that applies force by pressing the first temperature sensing element 331 against the device container 41.

[0069] When abnormalities such as pipe blockage or motor 3 lock-up occur in the refrigeration cycle, the temperature of the refrigerant and the temperature of the motor 3 sometimes rise simultaneously. On the other hand, even during normal operation, the temperature of the refrigerant and the temperature of the motor 3 sometimes rise simultaneously during refrigeration cycle startup or overload operation. Therefore, it is sometimes difficult to distinguish between normal operation and abnormal conditions by using a single temperature sensing element to monitor only the temperature changes of the refrigerant and compressor container 2.

[0070] In contrast, the inventors of this application focus on the following aspect: During normal operation, although the temperature of the motor 3 rises due to heat generated by the energizer, the temperature of the refrigerant rises only slightly because heat is dissipated through refrigerant circulation. Conversely, when an abnormality occurs and the refrigerant flow stops, the heat from the motor 3 continues to transfer to the refrigerant while it remains unheated, thus causing the refrigerant temperature to rise.

[0071] Therefore, the functional unit 30 includes: a first temperature sensing element 331, which is disposed at a position in contact with the device container 41; and a second temperature sensing element 332, which is disposed at a position away from the device container 41. Furthermore, the functional unit 30 makes an anomaly judgment based on the difference between the detected temperature of the first temperature sensing element 331 and the detected temperature of the second temperature sensing element 332. Thus, the functional unit 30 can accurately distinguish between normal operating states such as startup and overload operation, and abnormal states such as pipe blockage in the refrigeration cycle or motor 3 lockup.

[0072] In addition, the signal processing unit 34 can also continuously send an abnormality detection signal after determining an abnormal state, until the detection temperature of the first temperature detection element 331 or the second temperature detection element 332 reaches below the specified temperature.

[0073] The above-described embodiment is presented as an example and is not intended to limit the scope of the utility model. The above embodiments can be implemented by combining some or all of them. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the utility model. This embodiment and its variations are included within the scope and spirit of this utility model, and are included within the scope of the utility model and its equivalents as described in the claims.

[0074] Explanation of reference numerals in the attached figures

[0075] 1: Hermetic electric compressor; 2: Compressor container; 3: Electric motor; 3a: Electric motor wire; 4: Compression mechanism; 5: Abnormal detection device; 10: Control device; 20: Airtight terminal section; 21: Metal substrate; 22: Power supply terminal; 23: Signal terminal; 24: Electrically insulating filler material; 30: Functional part; 31: Housing; 34: Signal processing part; 35: Power supply terminal connection part; 36: Signal terminal connection part; 37: Heating element connection part; 40: Heating device; 41: Device container; 42: Pin; 43: Heating element; 44: Electrically insulating filling material; 311: Guide portion; 331: First temperature sensing element; 332: Second temperature sensing element; 411: Container portion; 412: Cover plate; D1: Outer diameter of power supply terminal; D2: Outer diameter of signal terminal; L1: Protrusion length of power supply terminal; L2: Protrusion length of signal terminal; W1: Contact length between power supply terminal and power supply terminal connection portion; W2: Contact length between signal terminal and signal terminal connection portion; O: Center of the arrangement of the three power supply terminals.

Claims

1. An anomaly detection device (5), which is installed in a hermetically sealed electric compressor (1), The hermetic electric compressor (1) comprises: an inverter-controlled electric motor (3); a compression mechanism (4) driven by the electric motor; and a compressor container (2) that houses the electric motor and the compression mechanism and is filled with refrigerant and refrigeration oil. The anomaly detection device (5) has an airtight terminal section (20) and a functional section (30). The airtight terminal section includes a metal substrate (21), a power supply terminal (22), and a signal terminal (23). The power supply terminal and the signal terminal are disposed through the metal substrate and are fixed to the metal substrate in an airtight and electrically insulating state using an electrically insulating filler material (24). The power supply terminal and the signal terminal are disposed through the compressor container. The functional unit is disposed within the compressor housing and includes: temperature detection elements (331, 332), a signal processing unit (34) for determining abnormalities based on the output of the temperature detection elements, and a resin housing (31) in which the temperature detection elements and the signal processing unit are disposed. The power supply terminal is electrically connected inside the compressor container to the motor lead wire (3a) leading from the motor, and outside the compressor container to the control device (10) that controls the motor. The signal terminal is connected to the signal processing unit inside the compressor housing and to the control device outside the compressor housing. If the signal processing unit determines that an anomaly is occurring, it sends an anomaly detection signal to the control device.

2. The anomaly detection device according to claim 1, wherein, The airtight terminal section has three power supply terminals and multiple signal terminals. The signal terminals are located in the region outside the circle that connects the centers of the three power terminals.

3. The anomaly detection device according to claim 1, wherein, The functional unit also has: A power supply terminal connection part (35) is provided in the housing, which electrically connects the power supply terminal to the motor wire by fixing the power supply terminal thereon; and A signal terminal connection part (36) is provided in the housing, and the signal terminal is electrically connected to the signal processing unit by fixing the signal terminal thereon. The outer diameter of the signal terminal is set to be smaller than the outer diameter of the power supply terminal. The length (L2) of the portion of the signal terminal protruding from the metal substrate into the compressor container is set to be shorter than the length (L1) of the portion of the power supply terminal protruding from the metal substrate into the compressor container. The axial length (W2) of the signal terminal that contacts the signal terminal connection portion is set to be shorter than the axial length (W1) of the power terminal that contacts the power terminal connection portion.

4. The anomaly detection device according to claim 1, wherein, The functional unit also has: A power supply terminal connection part (35) is provided in the housing, which electrically connects the power supply terminal to the motor wire by fixing the power supply terminal thereon; and A signal terminal connection part (36) is provided in the housing, and the signal terminal is electrically connected to the signal processing unit by fixing the signal terminal thereon. The functional unit also includes a heating element (40), which is disposed in the housing and connected in series between a power supply terminal connection and the motor wire connected to the power supply terminal connection. The heating device is configured to have: A metal device container (41) having a container portion (411) with an opening and a cover plate (412) that is hermetically disposed at the opening end of the container portion. The heating element (43), housed inside the device container, is made of a resistive material; and A pin (42), which penetrates the device container, is fixed to the cover plate in an airtight and electrically insulating state using an electrically insulating filler material. One end of the heating element is fixed to the pin, and the other end of the heating element is fixed to the device container. By connecting one of the pins or the device container to the power supply terminal and the other to the motor wire, the heating element is connected in series between the power supply terminal and the motor wire. The heating element is positioned in the housing such that a portion of the element's container is exposed within the compressor container. The plurality of temperature sensing elements include: a first temperature sensing element (331) disposed in contact with the device container; and a second temperature sensing element (332) disposed away from the device container.

5. The anomaly detection device according to claim 4, wherein, The housing also has a guide portion (311) which is disposed in a position opposite to the device container, so that the first temperature sensing element is positioned in contact with the surface of the device container.

6. The anomaly detection device according to claim 4, wherein, The signal processing unit makes an anomaly judgment based on the difference between the detected temperature of the first temperature detection element and the detected temperature of the second temperature detection element.

7. A hermetic electric compressor (1), comprising: The motor controlled by the inverter (3); The compression mechanism (4) is driven by the electric motor; A compressor container (2) that houses the electric motor and the compression mechanism, and is filled with refrigerant and refrigeration oil; and An anomaly detection device (5) according to any one of claims 1 to 6 is installed in the compressor container.

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