Motor protector unit, and electric compressor

Abstract

An electric motor protector unit according to an embodiment of the present application includes an electric motor protector, an electric motor protector holder, and a connection structure. The electric motor protector includes a hermetic container made of a housing and a cover, the housing having an opening and a space inside, the cover being provided to the housing and covering the opening, two conductive terminal pins provided to the cover with a filling material having electrical insulation therebetween, one end of each of the terminal pins being inserted into the hermetic container and the other end being exposed to the outside of the hermetic container, and a switching mechanism provided inside the hermetic container and switching electrical connection between the two conductive terminal pins. The electric motor protector holder includes a cover portion embedded in at least a portion of the electric motor protector and a wing portion formed in a plate shape extending in a right angle direction with respect to a long side direction of the conductive terminal pins. The connection structure connects and fixes the electric motor protector and the electric motor protector holder.

Description

Technical Field

[0001] Embodiments of the present invention relate to an electric motor protector unit and an electric compressor. Background Technology

[0002] Traditionally, electric compressors, for example, equipped with electric motors that operate at constant speeds, have motor protectors installed to prevent burnout in case of malfunction. These motor protectors have a heat-sensing plate that operates based on the ambient temperature inside the compressor and the heat generated by the current flowing through the motor protector. The operation of this heat-sensing plate opens the circuit, cutting off power to all windings of the motor.

[0003] In response to this, for example, in an inverter-driven electric compressor, since the inverter's control unit detects phase loss and abnormal current, a protection unit other than the control unit is not necessary. However, without a protection unit other than the control unit, abnormal current flowing to the electric compressor cannot be prevented in cases where the control unit malfunctions due to faults, incorrect wiring, or other reasons. Therefore, even in inverter-driven electric compressors, the demand for a protection unit different from the control unit is increasing to reliably protect the electric compressor from abnormal current. To address this demand, an external motor protector that does not change with the electric compressor is considered. However, external motor protectors are not very responsive to changes in the internal temperature of the compressor housing, such as winding temperature. Therefore, for reliable overheat protection, an internal protector installed inside the compressor housing is preferable.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2004-44408. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in structures where the motor protector is placed inside the compression container, there is a problem with the operability of installing the motor protector onto the motor.

[0009] This embodiment was made in view of the above circumstances, and its object is to provide a motor protector unit that can improve operability when a motor protector is installed on a motor using a motor protector retainer, and an electric compressor equipped with the motor protector unit.

[0010] Solution for solving the problem

[0011] The motor protector unit of the embodiment includes: a motor protector, a retainer for the motor protector, and a connecting structure. The motor protector has: a metal airtight container, which is airtightly constructed from a shell and a cover plate. The shell has an opening and an internal space, and the cover plate is disposed on the opening and covers the opening; two conductive terminal pins, which are disposed on the cover plate with an electrically insulating filler material, one end of which is inserted into the interior of the airtight container and the other end of which protrudes to the exterior of the airtight container; and a switching mechanism disposed inside the airtight container for switching the electrical connection between the two conductive terminal pins. The retainer for the motor protector has: a cover portion, which is embedded in at least a portion of the motor protector; and a wing portion, which is formed as a plate extending perpendicularly to the long side direction of the conductive terminal pins. The connecting structure connects and fixes the motor protector to the retainer for the motor protector.

[0012] The electric compressor of the embodiment includes: an electric motor that includes a compression mechanism and windings; a compressor housing that houses the compression mechanism and the electric motor; and the aforementioned electric motor protector unit, which is connected to the windings on the neutral point side of the electric motor and is housed within the compressor housing. Attached Figure Description

[0013] Figure 1 This is a perspective view showing an example of a motor protector unit according to one embodiment, with the motor protector embedded in the retainer, viewed from the top front side.

[0014] Figure 2 This is a perspective view showing an example of a motor protector unit according to one embodiment, with the motor protector embedded in the retainer, viewed from the upper rear side.

[0015] Figure 3 This is a perspective view showing an example of a motor protector unit according to one embodiment, with the motor protector embedded in the retainer, viewed from the lower front side.

[0016] Figure 4 This is a perspective view showing an example of a motor protector unit according to one embodiment, with the motor protector removed from the retainer, viewed from the top front side.

[0017] Figure 5 This is a perspective view showing an example of a motor protector unit according to one embodiment, with the motor protector removed from the retainer, viewed from the lower front side.

[0018] Figure 6 This is a front view showing an example of a motor protector unit according to one embodiment.

[0019] Figure 7 This is a top view showing an example of a motor protector unit according to one embodiment.

[0020] Figure 8 This illustrates an example of a motor protector unit according to one embodiment, showing a circuit along... Figure 6 A cross-sectional view showing the state of the winding connected by the X8-X8 line.

[0021] Figure 9 This illustrates an example of a motor protector unit according to one embodiment, showing a circuit along... Figure 8 A cross-sectional view showing the state of the winding connected by the X9-X9 line.

[0022] Figure 10 This illustrates an example of a motor protector unit according to one embodiment, showing a circuit along... Figure 8 A cross-sectional view showing the state of the winding connected by the X10-X10 line.

[0023] Figure 11 This illustrates an example of a motor protector unit according to one embodiment, showing a circuit along... Figure 8 A cross-sectional view showing the state of the winding connected by the X11-X11 line.

[0024] Figure 12 This is a diagram that schematically illustrates an example of the connection method when the motor protector unit according to one embodiment is applied to a three-phase motor.

[0025] Figure 13 This is a diagram that schematically illustrates an example of an electric compressor equipped with an electric motor protector unit according to one embodiment.

[0026] Figure 14 This is a simplified illustration of an electric compressor equipped with the motor protector unit according to one embodiment, representing a... Figure 13 A diagram of the peripheral portion of the X14-X14 line magnified motor protector unit. Detailed Implementation

[0027] Hereinafter, an embodiment of an electric motor protector unit 1 will be described with reference to the accompanying drawings. The electric motor protector unit 1 includes an electric motor protector 2, an electric motor protector retainer 3, and a connection structure 70. In the following description, the electric motor protector retainer 3 will sometimes be simply referred to as retainer 3.

[0028] The motor protector 2 is a motor protector built into a hermetic electric compressor used in applications such as air conditioners, and is particularly suitable for three-phase motors. The motor protector 2 is used, for example, to connect to the neutral point of a three-phase motor. The retainer 3 is a retainer used to hold the motor protector 2 and to mount the motor protector 2 to the electric compressor. The motor protector unit 1, for example, is capable of... Figure 1 and Figure 2 The motor protector unit 1 is installed in an orientation shown, with its vertical direction oriented towards the direction of gravity. However, the orientation in which the motor protector unit 1 is installed is not limited to the above-described orientation. For example, the motor protector unit 1 can also be installed in an orientation that is... Figure 1 and Figure 2 The motor is installed in various orientations, including upside-down and 90-degree rotation.

[0029] Hereinafter, an example of motor protector 2 will be described. However, the motor protector used in motor protector unit 1 is not limited to motor protector 2 described below. When a specified abnormal current flows through motor protector 2 and causes it to heat up, or when the motor itself heats up due to some abnormality, resulting in the ambient temperature rising to a specified temperature, motor protector 2 will activate and open the circuit. Thus, when motor protector 2 is activated, it disconnects the neutral point of the three-phase motor, cutting off the power supply to all windings of the motor.

[0030] like Figures 9 to 11 As shown, the motor protector 2 includes an airtight container 10, two conductive terminal pins 20, and a switching mechanism 30. The airtight container 10 forms the housing of the motor protector 2 and is airtight. Figure 4 , Figure 5 ,as well as Figures 9 to 11 As shown, the airtight container 10 has a shell 11 and a cover plate 12. The shell 11 is made of metal, for example, and is shaped like a dome with an open end and an internal space. The cover plate 12 is provided to cover the opening of the shell 11. The cover plate 12 is, for example, a plate-like member made of metal, and is shaped to fit along the opening portion of the shell 11. In this embodiment, the airtight container 10 is formed as a strip along the surface direction of the cover plate 12. The entire circumference of the cover plate 12 is fixed to the end of the shell 11 on the opening side by welding or the like, thus airtightly blocking the opening of the shell 11.

[0031] The conductive terminal pins 20 are made of conductive materials such as metal and are, for example, cylindrical rods. Two conductive terminal pins 20 pass through pin holes 121 formed in the cover plate 12, respectively, and are mounted on the cover plate 12 with one end inserted into the interior of the airtight container 10 and the other end protruding from the exterior of the airtight container 10. An electrically insulating filler material 13, such as glass, is provided between the inside of the pin holes 121 and the conductive terminal pins 20. The filler material 13 can also be called an insulating member. Thus, the conductive terminal pins 20 are fixed to the cover plate 12 in an electrically insulating and airtight state relative to the cover plate 12.

[0032] The conductive terminal pin 20 can adopt a structure having, for example, multiple layers with different properties. In this embodiment, the conductive terminal pin 20 is configured as a two-layer structure. Figure 8 and Figure 9 As shown, for example, the conductive terminal pin 20 can be configured to have a core material 21 and an outer material 22. The core material 21 forms the center portion of the conductive terminal pin 20. The outer material 22 is disposed on the outside of the core material 21, forming the outer surface of the conductive terminal pin 20. The conductive terminal pin 20 is configured to have: a core material 21 with high conductivity, such as copper, and an outer material 22 made of a material with higher stiffness than the copper core material 21, such as an iron-nickel alloy or a ferrite-based stainless steel.

[0033] The switching mechanism 30 is used to switch the electrical connection between the two conductive terminal pins 20. The switching mechanism 30 functions to disconnect the electrical connection by opening the connection between the two conductive terminal pins 20 when the ambient temperature inside the airtight container 10 is above a specified temperature. The switching mechanism 30 has two fixed contacts 31, two movable contacts 32, a support body 33, an elastic plate 34, and a heat-sensitive plate 35. The switching mechanism 30 is disposed within the airtight container 10. That is, the fixed contacts 31, movable contacts 32, support body 33, elastic plate 34, and heat-sensitive plate 35 are all disposed within the airtight container 10.

[0034] The fixed contacts 31 are made of a conductive metallic material, such as a silver oxide alloy and a cladding material of copper or a copper alloy. Two fixed contacts 31 are disposed inside the airtight container 10 and electrically connected to the conductive terminal pin 20. Each fixed contact 31 is fixed to the end of the airtight container 10 inside the conductive terminal pin 20, for example, by welding. In this case, it is preferable to plastically deform the fixed contacts 31 by pressing or the like after welding them to the conductive terminal pin 20, thereby aligning the height of each fixed contact 31.

[0035] Two movable contacts 32 correspond to two fixed contacts 31, respectively. Like the fixed contacts 31, the movable contacts 32 are made of a conductive metallic material, such as a silver oxide alloy or a cladding material of copper or a copper alloy. The two movable contacts 32 are disposed on the heat-sensitive plate 35, facing the fixed contacts 31 respectively. The movable contacts 32 are formed in a generally hemispherical shape protruding from the surface of the heat-sensitive plate 35 towards the cover plate 12 side. The movable contacts 32 are fixed to the heat-sensitive plate 35, for example, by welding.

[0036] The support body 33 is fixed to the inner surface of the housing 11 and functions to support the elastic plate 34 and the heat-sensitive plate 35. The support body 33 is formed, for example, by bending a rigid, elongated metal plate. The two ends of the support body 33 in the long direction are bent parallel to the inner surface of the housing 11 and fixed to the inner surface of the housing 11 by welding or the like. The central portion of the support body 33 in the long direction is separated from the inner surface of the housing 11.

[0037] The elastic plate 34 functions to elastically support the heat-sensitive plate 35. The elastic plate 34 is made of, for example, a thin sheet of metal that can be elastically deformed, and is generally shaped as an elongated oval. The heat-sensitive plate 35 is elastically connected to the elastic plate 34, either directly or through other components, by welding or other means. In this case, the elastic plate 34 is supported by the support body 33 as a two-end support beam with the central portion along the long side of the motor protector 2 as a fulcrum.

[0038] The heat-sensitive plate 35 has the following function: when the ambient temperature inside the airtight container 10 reaches or exceeds a specified temperature, that is, when its own temperature reaches or exceeds a specified temperature, it causes the movable contact 32 to move away from the fixed contact 31. The heat-sensitive plate 35 is formed, for example, by stretching a thin, conductive bimetallic or trimetallic sheet into a shallow dish shape. The heat-sensitive plate 35 is generally formed into an elongated oval shape with a longer longitudinal side in the direction of the motor protector 2. The two movable contacts 32 are respectively provided on the surfaces of the cover plates 12 at both ends of the elongated oval shape of the heat-sensitive plate 35 by welding or the like.

[0039] When the heat-sensitive plate 35 is not in operation, it keeps the movable contacts 32 in contact with the fixed contacts 31, maintaining a closed state between the two fixed contacts 31. In addition, when the ambient temperature inside the airtight container 10 reaches a predetermined temperature, the heat-sensitive plate 35 operates, thereby deforming the movable contacts 32 away from the fixed contacts 31, opening the space between the fixed contacts 31.

[0040] That is, when the heat-sensitive plate 35 is not in operation, the heat-sensitive plate 35 is bent towards the cover plate 12 with its central portion along its long side as the apex and both ends along its long side, i.e., the movable contact 32 sides, as the two ends of the long side. Therefore, each fixed contact 31 contacts its respective opposing movable contact 32, and thus, the two fixed contacts 31 are electrically connected via the movable contact 32 and the heat-sensitive plate 35. In other words, in this case, the two conductive terminal pins 20 are electrically connected via the fixed contact 31, the movable contact 32, and the heat-sensitive plate 35. Furthermore, the two conductive terminal pins 20 are electrically connected to the airtight container 10 via the fixed contact 31, the movable contact 32, the heat-sensitive plate 35, the elastic plate 34, and the support 33.

[0041] Then, when the ambient temperature inside the airtight container 10 rises to the specified operating temperature of the heat induction plate 35, the heat induction plate 35 operates and deforms in the direction of bending reversal. As a result, the movable contact 32 is pulled away from the fixed contact 31, and the electrical connection between the two fixed contacts 31, that is, between the two conductive terminal pins 20, and between each conductive terminal pin 20 and the airtight container 10, is cut off.

[0042] like Figure 2 , Figure 4 , Figure 6 ,as well as Figure 8 As shown, the motor protector 2 can also be further configured to include a heating element 40. The heating element 40 is located outside the airtight container 10 and is fixed to the conductive terminal pin 20. The motor winding 91 is mounted on the heating element 40, for example, and is electrically connected to the conductive terminal pin 20 via the heating element 40. In this case, the winding 91 connected to the heating element 40 does not directly contact the conductive terminal pin 20. The heating element 40 is made of a different material than the conductive terminal pin 20. The heating element 40 is located between the conductive terminal pin 20 and the motor winding 91, and has the function of generating heat by the flow of current. The heating element 40 is formed by bending a conductive material, such as a metal plate, and is attached to the conductive terminal pin 20 by welding or the like. Alternatively, the connection between the heating element 40 and the winding 91 can be structured such that a lead wire is pre-connected to the heating element 40, and this lead wire is electrically connected to the winding 91.

[0043] The heating element 40 is made of a conductive material with a resistivity greater than that of any of the conductive terminal pin 20, fixed contact 31, movable contact 32, elastic plate 34, and thermal sensing plate 35. The material of the heating element 40 can be, for example, resistive or electrothermal materials such as nickel-chromium, copper-nickel, copper-manganese, or iron-chromium. The heating element 40 is formed, for example, by bending a sheet of electrothermal material.

[0044] In this embodiment, the resistance between the two heating elements 40 is set to be between four and eight times the resistance between the two conductive terminal pins 20. Therefore, when the same current flows between the two heating elements 40 and between the two conductive terminal pins 20, the heat generated between the two heating elements 40 is greater than the heat generated between the two conductive terminal pins 20. Furthermore, the resistance between the heating elements 40 includes the resistance of the electrical path existing between the heating elements 40, namely the resistance of the conductive terminal pins 20, the fixed contact 31, the movable contact 32, and the thermal sensing plate 35.

[0045] Next, the retainer 3 will be described. The retainer 3 is used to mount the motor protector 2 to the electric compressor. The retainer 3 is made of, for example, an electrically insulating resin material. Figures 1 to 8 As shown, the retainer 3 includes a wing portion 50 and a cover portion 60. In this embodiment, the wing portion 50 and the cover portion 60 are integrated. Furthermore, in this specification, "the wing portion 50 and the cover portion 60 are integrated" means that the wing portion 50 and the cover portion 60 are not bonded or joined, but rather formed into a seamless structure through resin molding or the like.

[0046] The wing 50 is the portion that contacts the motor windings when the motor protector unit 1 is installed onto the motor. The wing 50 increases the contact area and stabilizes the posture of the retainer 3 during installation onto the motor. The wing 50 extends outwards relative to the cover 60. The wing 50 is formed, for example, in a flat plate shape extending relative to the cover 60 in a direction perpendicular to the long side direction of the conductive terminal pin 20, i.e., the extending direction. Figures 1 to 5 As shown, the wing 50 is formed as a gently curving arc. The back of the wing 50 and the cover 60, that is, the side opposite to the side of the motor protector 2, is formed as a flat surface without any protrusions.

[0047] A cover 60 is located at the center of the long side of the retainer 3. The cover 60 is into which at least a portion of the motor protector 2 is embedded, and covers a portion of the area surrounding the heating member 40. The cover 60 has, for example, a lower surface 61, two side surfaces 62, an upper surface 63, and a back surface 64. The lower surface 61 is formed as a continuous plane with the wing 50, constituting the bottom surface of the cover 60. The two side surfaces 62 extend perpendicularly to the lower surface 61 at mutually separated positions. The upper surface 63 is located facing the lower surface 61, connecting the opposite ends of the lower surface 61 of the two side surfaces 62.

[0048] The cover portion 60 is generally formed into a rectangular ring or cylinder by the lower surface portion 61, two side surface portions 62, and the upper surface portion 63, thereby housing the motor protector 2 inside the cover portion 60. Figure 6 As shown, when the motor protector 2 is housed inside the cover 60, there is a gap S1 between the lower surface 61 and the motor protector 2, and a gap S2 between the side surface 62 and the motor protector 2.

[0049] In addition, such as Figure 2 As shown, the back surface portion 64 is formed in the shape of a plate and is connected to the lower surface portion 61 and portions of the lower surface portions 61 of the two side surface portions 62. The back surface portion 64 covers the side of the airtight container 10 housed in the motor protector 2 within the cover portion 60. In this case, as... Figure 4 and Figure 5 As shown, the motor protector 2 is embedded into the inside of the cover 60 from the side opposite to the back part 64.

[0050] The back portion 64 has the function of improving the mechanical strength of the retainer 3 and ensuring the insulation distance from the motor and compression mechanism when the motor protector unit 1 is installed in the motor. Furthermore, as... Figure 14 As shown, the motor protector unit 1 is mounted to the motor 90, for example, using a binding wire 95. In this case, the back portion 64 prevents the binding wire 95 from contacting the motor protector 2, thereby preventing the binding wire 95 from contacting the high-temperature motor protector 2 and burning out.

[0051] The retainer 3 has a lower side hole 611, limiting portions 621 and 641, a flow portion 631, a recessed portion 632, and an upper side hole 633. For example... Figure 4 and Figure 9 As shown, the lower hole 611 is a hole formed through the center portion of the lower surface portion 61. The lower hole 611 is located opposite to the center portion of the apex of the housing 11 in the airtight container 10 of the motor protector 2 housed in the cover portion 60.

[0052] like Figure 9 As shown, a limiting part 621 is provided on the side surface part 62. Furthermore, as... Figure 11 As shown, a limiting part 641 is provided on the back surface 64. Each limiting part 621, 641 is formed by making a portion of the side surface 62 and the back surface 64 into a stepped shape, for example, to lock onto a portion of the edge of the cover plate 12. For the motor protector 2 housed in the cover 60, the limiting parts 621, 641 restrict the movement of the motor protector 2 towards the upper surface 63 by contacting the edge of the cover plate 12. That is, the limiting parts 621, 641 have the function of defining the distance between the lower surface 61 and the motor protector 2, and the distance between the upper surface 63 and the motor protector 2.

[0053] A flow-through portion 631, a recessed portion 632, and an upper hole portion 633 are provided on the upper surface portion 63. The flow-through portion 631 is a hole formed through the upper surface portion 63, and is shaped and sized to allow refrigerant to flow through. Figure 1 , Figure 2 , Figure 4 ,as well as Figures 9 to 11 As shown, the recess 632 is formed by recessing a portion of the upper surface portion 63 from its outer side. The recess 632 is located at the center of the long side of the upper surface portion 63, corresponding to a position near the center of the cover plate 12 of the motor protector 2. Figure 1 , Figure 4 , Figure 10 ,as well as Figure 11 As shown, the upper hole 633 is provided inside the recess 632 and is formed by penetrating the bottom of the recess 632. That is, the upper hole 633 is formed by penetrating the upper surface portion 63.

[0054] Furthermore, the retainer 3 has a retaining portion 65, a receiving portion 66, a guiding portion 67, a protrusion 68, and an opening 69. For example... Figure 8 As shown, the retaining part 65 has the function of clamping and holding the winding 91 of the motor connected to the motor protector 2. The retaining part 65 is provided on both sides with respect to the center of the long side of the motor protector 2. For example, the retaining part 65 can hold one of the three windings 91 of a three-phase motor connected to the motor protector 2. In this case, the retainer 3 can lead the three windings 91 of the three-phase motor connected to the motor protector 2 out in the same direction, that is, out from one side, without contacting the heating element 40 or the conductive terminal pin 20.

[0055] Furthermore, the retainer 3 has retaining portions 65 at positions symmetrically positioned relative to the long side of the motor protector 2. Therefore, one of the three windings 91 can be led out in a direction different from the other two windings. In this case, since the retaining portions 65 can hold the two windings 91 extending to both sides respectively, the assemblies and operability of the motor are improved.

[0056] like Figure 4 , Figure 6 , Figures 9 to 11 As shown, a bearing portion 66 is provided on the inner surface side of the lower surface portion 61. The bearing portion 66 is formed in a semi-circular shape, for example, protruding from the lower surface portion 61 into the upper surface portion 63 side profile. Furthermore, the bearing portion 66 extends linearly in a direction perpendicular to the long side direction of the retainer 3, i.e., in the width direction of the retainer 3. Two bearing portions 66 are provided on both sides, sandwiching the center of the lower surface portion 61 in the long side direction. The bearing portion 66 is used to ensure the gap S1 between the motor protector 2 and the lower surface portion 61.

[0057] That is, when the motor protector 2 is disposed within the cover portion 60, the portion of the motor protector 2 opposite to the side of the cover plate 12 is separated from or in contact with the support portion 66. In this case, since the support portion 66 protrudes from the lower surface portion 61 to the upper surface portion 63, even if the motor protector 2 is in contact with the support portion 66, the gap S1 between the motor protector 2 and the lower surface portion 61 can be ensured.

[0058] like Figure 1 , Figure 4 , Figure 6 ,as well as Figure 7 As shown, the guide portion 67 has multiple portions on the upper surface portion 63, protruding outward from the upper surface portion 63. For example... Figure 14 As shown, the motor protector unit 1 is mounted to the coil winding 91 of the motor 90 by binding with a binding wire 95, with the motor protector 2 embedded and held in the retainer 3. The binding wire 95 is made of a material such as resin that has electrical insulation and flexibility. The retainer 3, which holds the motor protector 2, is mounted in the compressor housing 81 with the heating element 40 exposed to the flow of refrigerant generated during normal operation of the compressor 80.

[0059] The guide portion 67 has the function of guiding the position of the binding wire 95, that is, maintaining it in a fixed position. Specifically, the binding wire 95 of the motor protector unit 1 is held in place by the guide portion 67, thus preventing positional deviation. Therefore, the motor protector unit 1 can be reliably fixed to the motor. Alternatively, the guide portion 67 may be, for example, a groove formed on the upper surface portion 63.

[0060] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 7 , Figure 8 ,as well as Figure 14 As shown, one or more protrusions 68 are provided at the edge of the lower surface portion 61, forming a shape that protrudes outward in an arc shape from the lower surface portion 61 and the wing portion 50. Figure 14 As shown, the protrusion 68 has the following function: when the motor protector unit 1 is installed in the motor 90 inside the compressor container 81, the protrusion 68 contacts the inner wall of the compressor container 81 before the motor protector 2, thereby preventing the motor protector 2 from directly contacting the compressor container 81. This prevents the motor protector 2, which is a charging part, from approaching the inner wall of the compressor container 81, which is a non-charging part, and making electrical contact due to vibration of the compressor 80, improper assembly of the motor protector unit 1, etc.

[0061] like Figure 2As shown, the opening 69 is formed between the side surface portion 62 and the back surface portion 64 near the lower surface portion 61. The opening 69 connects the interior and exterior of the cover portion 60, and is configured to allow refrigerant to flow through.

[0062] like Figure 11 As shown, the connecting structure 70 is used to connect and fix the motor protector 2 and the retainer 3. In this embodiment, the connecting structure 70 connects and fixes the motor protector 2 and the retainer 3 in a non-separable manner. Furthermore, in this embodiment, "connected and fixed in a non-separable manner" means that they are connected and fixed in a way that prevents them from being separated unless a certain structure is destroyed or removed. Figures 9 to 11 As shown, the connection structure 70 has gaps S1 and S2 between the motor protector 2 and the retainer 3, through which refrigerant can pass, and connects the motor protector 2 and the retainer 3.

[0063] In this embodiment, the connecting structure 70 connects the motor protector 2 and the retainer 3 while the motor protector 2 is suspended on the upper surface portion 63. That is, the retainer 3 holds the motor protector 2 with the conductive terminal pin 20 protruding upward in the vertical direction.

[0064] The connecting structure 70 can be configured as having a retainer-side member 71 and a protector-side member 72. Both the retainer-side member 71 and the protector-side member 72 are made of metallic material. Figure 5 , Figure 10 ,as well as Figure 11 As shown, a member 71 on one side of the retainer is provided on the upper surface portion 63, and a portion of it extends through the upper surface portion 63 to the lower surface portion 61.

[0065] The component 71 on one side of the retainer is made of metal, such as... Figure 4 and Figure 10 As shown, for example, the entire assembly is formed in a T-shape. In this case, the member 71 on the retainer side has an insertion portion 711 and a locking portion 712. The insertion portion 711 is the part of the T-shape that extends through the upper surface portion 63 to the lower surface portion 61. The locking portion 712 is the part of the T-shape that extends in a direction perpendicular to the extending direction of the insertion portion 711.

[0066] When the member 71 on the retainer side is installed onto the retainer 3, the insertion part 711 is inserted into the upper hole 633 from the outside to the inside of the upper surface part 63. Then, the locking part 712 is locked at the bottom of the recess 632, that is, around the upper hole 633, and the insertion part 711 extends through the upper surface part 63 to the lower surface part 61.

[0067] The component 72 on one side of the protector is made of metal and is, for example, L-shaped. A portion of the L-shape of the component 72 on the protector side is welded and fixed to the cover plate 12. Then, as... Figure 11 As shown, another part of the L-shape of the component 72 on the protector side extends vertically from the cover plate 12 and is welded and fixed to the insertion part 711 of the component 71 on the retainer side. Thus, the motor protector 2 is fixed to the retainer 3 in an attitude in which the component 71 on the retainer side and the component 72 on the protector side are interconnected and suspended on the upper surface part 63.

[0068] Here, when the motor protector 2 is fixed to the retainer 3 via the connecting structure 70, for example... Figure 10 and Figure 11 As shown, the rod-shaped clamp T is passed through the lower hole 611 to lift the motor protector 2, and the periphery of the cover plate 12 is pressed against the limiting parts 621 and 641. Then, with the periphery of the cover plate 12 pressed against the limiting parts 621 and 641 by the clamp T, the member 71 on the retainer side and the member 72 on the protector side are welded and fixed. Thus, the motor protector 2 and the retainer 3 are fixed in such a way that the retainer 3 is clamped by the locking part 712 of the member 71 on the retainer side and the cover plate 12. As a result, the motor protector 2 and the retainer 3 are firmly fixed to each other in a state that reduces shaking.

[0069] Next, the electric compressor 80 on which the motor protector unit 1 is installed, and the method for installing the motor protector unit 1 onto the electric compressor 80 will be described. Figure 7 As shown, for example, the motor protector 2 is used in connection with the neutral point of the motor 90. In this case, the power supply side ends of the three-phase windings 91 of the motor 90 are connected to the three-phase power supply via power supply terminals 92. Furthermore, regarding the neutral point side ends of each winding 91, two windings of the three-phase windings 91 are connected to the heating element 40. Then, the windings 91 connected to the heating element 40 are electrically connected to the fixed contact 31 via conductive terminal pins 20. In addition, the remaining winding of the three-phase windings 91 is fixed to a metal part outside the airtight container 10, such as the cover plate 12, for example by welding. Then, the winding 91 connected to the cover plate 12 is electrically connected to the movable contact 32 via the housing 11, the support 33, the elastic plate 34, and the heat-sensing plate 35. Alternatively, the connection between the heating element 40 and the windings 91 can also be structured such that a lead wire is pre-connected to the heating element 40, and this lead wire is electrically connected to the windings 91.

[0070] Figure 13 and Figure 14This is an example of installing the motor protector unit 1 with the above-described structure in a hermetic electric compressor 80. It should be noted that in the following description, the hermetic electric compressor 80 will sometimes be simply referred to as compressor 80. Compressor 80 is a fully hermetic or semi-hermetic electric compressor for refrigerants, used, for example, in air conditioning systems and capable of forming part of a refrigeration cycle. Furthermore, compressor 80 is not limited to small to medium-sized models with small capacities; it can also be a large-capacity model.

[0071] The compressor 80 includes a compressor housing 81, a compression mechanism 82, an electric motor 90, and an electric motor protector unit 1. The compressor housing 81 is an airtight and pressure-resistant container that forms the casing of the compressor 80. Both the compression mechanism 82 and the electric motor 90 are housed within the compressor housing 81. That is, the compressor housing 81 houses the compression mechanism 82 and the electric motor 90, which includes windings 91. The compression mechanism 82 has the function of compressing and dispensing refrigerant. The compression mechanism 82 can be, for example, not only a scroll type but also a rotary vane type.

[0072] The electric motor 90 has windings 91 and drives the compression mechanism 82. Furthermore, the compressor container 81 is hermetically connected to a suction pipe 83 and a discharge pipe 84. The suction pipe 83 guides refrigerant into the compression mechanism 82 within the compressor container 81 through a heat exchanger (not shown). The discharge pipe 84 sprays the refrigerant compressed by the compression mechanism 82 and delivers it to a heat exchanger (not shown). It should be noted that, in this specification, the refrigerant also includes refrigeration oil, i.e., lubricating oil, which lubricates the compression mechanism 82.

[0073] like Figure 14 As shown, the motor protector unit 1 is mounted on the coil winding 91 of the motor 90 by being bound with a binding wire 95. The binding wire 95 is made of a material such as resin that has electrical insulation and flexibility. The motor protector unit 1 is mounted on the winding 91 inside the compressor container 81 in such a manner that the heating element 40 is exposed to the flow of refrigerant generated during the normal operation of the compressor 80.

[0074] When the compressor 80 is operating, the compressor container 81 is filled with refrigerant containing atomized lubricating oil, creating a flow of refrigerant from the suction pipe 83 toward the discharge pipe 84. Therefore, the motor protector unit 1 is located, for example, within the compressor container 81, downstream of the compression mechanism 82, i.e., between the motor 90 and the discharge pipe 84. During compressor 80 operation, a portion of the refrigerant flowing from the suction pipe 83 to the discharge pipe 84 enters and exits through the openings 69 on the front and back sides of the motor protector unit 1, flowing through gaps S1 and S2, thereby cooling the motor protector 2.

[0075] According to the embodiment described above, the motor protector unit 1 includes a motor protector 2, a retainer 3, and a connection structure 70. The motor protector 2 has a metal airtight container 10, two conductive terminal pins 20, and a switching mechanism 30. The airtight container 10 is airtightly constructed from a housing 11 and a cover plate 12. The housing 11 has an opening and an internal space, and the cover plate 12 is disposed on the housing 11 and covers the opening. The conductive terminal pins 20 are disposed on the cover plate 12 through an electrically insulating filler material 13, with one end inserted into the interior of the airtight container 10 and the other end protruding outside the airtight container 10. The switching mechanism 30 is disposed inside the airtight container 10 and switches the electrical connection between the two conductive terminal pins 20.

[0076] The retainer 3 has a wing 50 and a cover 60. The cover 60 is for at least a portion of the motor protector 2 to be inserted. The wing 50 is formed as a plate extending in a direction perpendicular to the long side of the conductive terminal pin 20. Furthermore, the connecting structure 70 connects and fixes the motor protector 2 and the retainer 3 in an inseparable manner.

[0077] Therefore, since the motor protector 2 and the retainer 3 in the motor protector unit 1 are connected and fixed as a unit through the connection structure 70, the motor protector 2 and the retainer 3 can be prevented from separating when they are installed on the motor 90. Thus, the operability of installing the motor protector 2 on the motor 90 using the retainer 3 is improved.

[0078] In this embodiment, the motor protector unit 1 is arranged along the outer periphery of the winding 91, and is mounted such that the wing 50 of the retainer 3 is located on the winding 91 side, that is, the outer surface of the wing 50 contacts the winding 91. Furthermore, the motor protector unit 1 has the heating element 40 positioned towards the outer periphery of the compressor housing 81. The compressor 80 is driven by a power supply controlled by an inverter, and the current during lock-up is set to be equal to or less than the current during normal overload operation. That is, when the compressor 80 is driven by a power supply controlled by an inverter, by providing the aforementioned motor protector unit 1, the current during lock-up can be set to be equal to or less than the current during normal overload operation.

[0079] Here, a state in which one or more phases of the three-phase power supply to the motor are not energized due to a broken power supply line, poor contact at the wire connection, a fault in the power control circuit, or a broken wire inside the motor is called "phase loss." When starting the compressor, if the motor is energized in a phase loss state, it will result in insufficient torque, and the motor rotor will not rotate in a locked state, allowing the starting current to continue flowing through the motor. Since the starting current is larger than the normal operating current, when the starting current continues to flow through the motor in a phase loss state, the balance of the phases at the neutral point is disrupted, and an abnormal current will flow. This starting current, which occurs when attempting to start the motor in a phase loss state, is usually called "phase loss lockout current."

[0080] When a phase loss causes the rotor to lock up, the flow of refrigerant containing refrigeration oil (lubricating oil) slows down. As a result, the motor cannot be cooled by the refrigerant flow. Furthermore, as the rotor remains locked up and the phase loss lockout current continues to flow through the motor, the motor temperature will rise sharply due to Joule heating, potentially causing the motor to burn out in the worst case. Therefore, it is important to detect the phase loss lockout current and cut off the power supply to the motor.

[0081] However, in the case of inverter-controlled motors, due to high-voltage and high-current operating modes, the difference between the phase-loss lockout current and the motor's rated maximum current may become smaller. In this situation, if the operating temperature required for the thermal sensor to operate is set accordingly to the heat generated by the phase-loss lockout current, the thermal sensor may operate even within the rated maximum current range, becoming a cause of malfunction. To address this, if the operating temperature required for the thermal sensor to operate is set too high, so that the thermal sensor does not operate even at the rated maximum current, the temperature rise within the motor protector due to the phase-loss lockout current requires time. As a result, in the event of phase-loss lockout, it is impossible to heat the thermal sensor to the operating temperature quickly enough; time is required before the motor protector cuts off the phase-loss lockout current, during which time the motor temperature may rise to a dangerous level.

[0082] Therefore, the connection structure 70 of this embodiment has gaps S1 and S2 between the motor protector 2 and the retainer 3, allowing refrigerant to pass through, and connects and fixes the motor protector 2 and the retainer 3. This prevents the motor protector 2 from malfunctioning within its rated maximum current range, and also prevents it from operating under abnormal conditions caused by overcurrent or lockout current. That is, when the motor 90 operates at its rated maximum current, since it is within the normal operating range, the compressor 80 does not stop, and the refrigerant in the compressor container 81 continues to flow. Furthermore, the refrigerant flowing in the compressor container 81 cools the motor protector 2 itself through gaps S1 and S2. Therefore, even when the rated maximum current flows through the motor 90, the airtight container 10 is cooled by the refrigerant flow, preventing the temperature inside the airtight container 10 from reaching the operating temperature of the heat-sensing plate 35. Therefore, in this situation, the motor protector 2 does not operate, and power continues to be supplied to the motor 90.

[0083] Conversely, when the motor 90 experiences an abnormality such as phase loss lock-up, and the compressor mechanism 82 stops operating, the flow of refrigerant in the compressor container 81 weakens or stops. The cooling of the motor protector 2, which utilizes the refrigerant, also decreases, resulting in a rise in temperature inside the airtight container 10. Furthermore, when the temperature inside the airtight container 10 reaches the operating temperature of the heat sensor 35, the heat sensor 35 activates, which means the motor protector 2 activates, cutting off the power supply to the motor 90.

[0084] Thus, according to the motor protector unit 1 of this embodiment, even when the rated maximum current of the motor 90 is close to the phase-loss lockout current, and when the motor 90 is operating within the rated maximum current, the motor protector 2 will not operate. On the other hand, when the motor 90 is locked and a phase-loss lockout current flows, the motor protector 2 can be activated for a short time. As a result, it is possible to reliably suppress malfunctions operating within the rated maximum current and to prevent operation even under abnormal conditions caused by overcurrent or lockout current. Furthermore, such a motor protector unit 1 is more suitable for electric compressors driven by an inverter-controlled power supply, where the current during lockout is set to be equal to or less than the current during normal overload operation.

[0085] Furthermore, the cover portion 60 also includes: an upper surface portion 63 that covers one side of the cover plate 12 of the motor protector 2; and a lower surface portion 61 that covers the opposite side of the cover plate 12. The connecting structure 70 has a retainer-side member 71 and a protector-side member 72. The retainer-side member 71 is provided on the upper surface portion 63 and extends towards the lower surface portion 61. The protector-side member 72 is provided on the cover plate 12 and extends towards the upper surface portion 63. Moreover, the motor protector 2 is fixed to the retainer 3 in a posture in which the retainer-side member 71 and the protector-side member 72 are interconnected and suspended on the upper surface portion 63. Thus, since the motor protector 2 is fixed in a suspended posture relative to the retainer 3 by the connecting structure 70, the gaps S1 and S2 around the motor protector 2 can be ensured as large as possible. As a result, it is easy to ensure the amount of refrigerant flowing around the motor protector 2, and under normal operating conditions that generate refrigerant flow, the motor protector 2 is efficiently cooled, thus suppressing malfunctions of the motor protector 2.

[0086] The retainer 3 is made of resin and has an upper hole 633 formed through the upper surface portion 63. Furthermore, the retainer-side member 71 is made of metal and has an insertion portion 711 and a locking portion 712. The insertion portion 711 is inserted into the upper hole 633 from the outside to the inside of the upper surface portion 63. The locking portion 712 extends outward relative to the extension direction of the insertion portion 711 and is locked onto the upper surface portion 63. Moreover, the protector-side member 72 is made of metal and is welded to the insertion portion 711. Therefore, by making the retainer-side member 71 and the protector-side member 72 of the connecting structure 70 metal and welding them together, the motor protector 2 can be reliably fixed by the retainer 3.

[0087] Furthermore, the retainer 3 also has a lower side hole 611 and limiting portions 621 and 641. The lower side hole 611 is formed through the lower surface portion 61. The limiting portions 621 and 641 contact the motor protector 2, restricting the movement of the motor protector 2 towards the upper surface portion 63. Thus, with the motor protector 2 pressed against the limiting portions 621 and 641, the motor protector 2 and the retainer 3 are fixed by welding the retainer-side member 71 of the connecting structure 70 to the protector-side member 72, thereby clamping the retainer 3 between the retainer-side member 71's locking portion 712 and the cover plate 12. As a result, the wobbling of the motor protector 2 and the retainer 3 is reduced, and it is possible to suppress the motor protector 2 from falling off the retainer 3 due to vibrations of the electric compressor 80, etc.

[0088] The above-described embodiment is provided as an example and is not intended to limit the scope of the invention. This new embodiment can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its variations are included in the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

Claims

1. A motor protector unit, comprising: a motor protector, a retainer for the motor protector, and a connection structure. The motor protector has the following features: An airtight metal container comprising a shell and a cover plate, the shell having an opening and an interior space, the cover plate being disposed on the shell and covering the opening; Two conductive terminal pins are disposed on the cover plate through an electrically insulating filler material, with one end inserted into the interior of the airtight container and the other end protruding to the exterior of the airtight container; as well as A switching mechanism, disposed inside the airtight container, switches the electrical connection between the two conductive terminal pins. The retainer for the motor protector has: A cover portion, into which at least a portion of the motor protector is embedded; as well as The wing is formed as a plate extending perpendicularly to the long side of the conductive terminal pin. The connection structure connects and fixes the motor protector to the motor protector using a retainer.

2. The motor protector unit according to claim 1, wherein, The connection structure has a gap between the motor protector and the retainer for the motor protector, allowing refrigerant to pass through, and connects the motor protector to the retainer for the motor protector.

3. The motor protector unit according to claim 2, wherein, The cover portion further comprises: an upper surface portion that covers one side of the cover plate of the motor protector; and a lower surface portion that covers the opposite side of one side of the cover plate. The connecting structure includes: a member on the retainer side, which is disposed on the upper surface portion and extends towards the lower surface portion; and a member on the protector side, which is disposed on the cover plate and extends towards the upper surface portion. The motor protector is fixed to the retainer of the motor protector in an attitude in which a component on one side of the retainer is connected to a component on the other side of the protector and is suspended on the upper surface.

4. The motor protector unit according to claim 3, wherein, The retainer for the motor protector is made of resin and also has an upper side hole formed through the upper surface portion. The component on one side of the retainer is made of metal and further includes: an insertion portion that inserts into the upper hole portion from the outer side to the inner side of the upper surface portion; and a locking portion that extends outward relative to the extending direction of the insertion portion and locks into the upper surface portion. The component on one side of the protector is made of metal and is welded to the insertion part.

5. The motor protector unit according to claim 4, wherein, The retainer for the motor protector also has: The lower side hole is formed through the lower surface portion; and A limiting part contacts the motor protector and restricts the movement of the motor protector toward the upper surface portion.

6. An electric compressor, comprising: An electric motor, which includes a compressor and windings; Compressor housing, which houses the compression mechanism and the electric motor; and The motor protector unit according to any one of claims 1 to 5, wherein the motor protector is connected to the winding on the neutral point side of the motor and is housed within the compressor container.

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