Motor stator

Abstract

To provide a motor stator that eliminates deformation stress on the coil wires. [Solution] A circuit board 9 is mounted at a distance from the motor coil end ring 5 protruding from the motor stator 1 body, grooves 17 and holes 18 for passing multiple motor coil windings are provided in the circuit board, and the ends of the winding ends of the multiple motor coil windings are electrically connected to the surface of the circuit board opposite to the surface facing the motor coil end ring, thereby eliminating deformation stress on the coil wires and reducing rare short-circuit failures. In current AC three-phase induction motor stators, connection parts such as the neutral point are pressed between the coil layers to form the structure, causing deformation stress on the coil wires and leading to rare short-circuit failures.

Description

Technical Field

[0001] The present invention relates to a motor stator with an improved connection method for coil windings in single-phase AC induction motors and three-phase AC induction motors (hereinafter, the motor is referred to as a "motor").

Background Art

[0002] Compressor manufacturers use many motors. Generally, the motor stator (hereinafter sometimes referred to as a "stator") and the motor rotor (hereinafter sometimes referred to as a "rotor") are handled and sold as a set. In that case, in addition to dimensional accuracy, excellent appearance is required as a stator specification. In order to improve the appearance, conventionally, the insulated connection part of the coil winding (copper wire) has been pushed into the coil layer so that the connection part of the coil winding (electrical connection part) cannot be seen on the coil end ring of the motor, and after making the connection part invisible from the outside, the coil end dimensions have been compressed within the standard by a coil shaping press. In this press process, compressive stress is applied to the coil windings around the connection part, and there is a potential risk of causing a decrease in reliability such as shortening the life of the motor because deformation such as indentation often occurs in the coil windings and develops into a rare short circuit of the coil. Since these deformations of the coil windings occur inside the coil end ring, they cannot be confirmed from the outside. In addition, although a rare short circuit tester is used as a quality inspection method, there is a problem that detection cannot be performed unless it is in a complete open circuit state or a short circuit state.

[0003] Figure 18 provides a supplementary explanation of how stress on coil windings can cause rare short circuits. When localized pressure is applied to the coil windings, deformation occurs in the insulated coil windings. This deformation reduces the cross-sectional area, leading to an increase in current density in that area, which in turn causes localized heat generation. Furthermore, deformation of the insulating film reduces its thickness, leading to a decrease in insulation resistance. This localized heat generation causes the insulating film to burn out, resulting in a rare short circuit occurring in the deformed portion of the copper wire, ultimately leading to wire breakage. As described above, deformation of the copper wire significantly affects reliability.

[0004] Similar problems concerning the arrangement of winding connections in motor stators are likely to become even more significant in the automotive industry, where demand is expected to increase as electric vehicles (EVs) become more prevalent. In particular, in the case of EVs, motor failure during operation can lead to accidents and endanger human lives, making improved reliability far more critical than that of compressors in refrigeration equipment, for example.

[0005] In response to the above problems, the inventor of the present invention has filed a patent application (Patent Document 1) for a method in which a substrate is provided on the outside of the coil end ring, and the coil winding connection portion is connected to the printed copper wiring on the substrate by soldering or the like, or the connection portion pulled out through a hole drilled in the substrate is fixed with a crimp terminal. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2024-74741 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, the invention disclosed in Patent Document 1 has problems such as the inability to stably fix the substrate, and the need for manual work to pass the coil windings through holes drilled in the substrate in AC single-phase induction motors and AC three-phase induction motors used in compressors, etc., which makes the work difficult and makes it difficult to automate or reduce costs. In other words, the object of the present invention is to provide a motor stator with an improved method for fixing the connection part of the coil windings, which makes assembly work easy and can be automated. [Means for solving the problem]

[0008] This invention relates to a motor stator characterized by mounting a substrate at a distance from the motor coil end ring protruding from the motor stator body, providing grooves and holes in the substrate for passing a plurality of motor coil windings through, and electrically connecting the ends of the winding ends of the plurality of motor coil windings to the surface of the substrate opposite to the surface facing the motor coil end ring.

[0009] Furthermore, this invention is a motor stator in which the ends of the winding ends of the multiple motor coil windings are electrically connected by soldering using copper foil that has been continuously printed on the surface of the substrate opposite to the surface facing the motor coil end ring.

[0010] Furthermore, this invention is a motor stator in which the grooves and holes of the substrate are used to position the winding ends of the multiple motor coil windings.

[0011] Furthermore, the present invention is a motor stator in which the ends of the winding ends of the plurality of motor coil windings are electrically connected to a single motor coil winding on the surface of the substrate opposite to the surface facing the motor coil end ring, and the plurality of motor coil windings are adhesively fixed to the surface of the substrate opposite to the surface facing the motor coil end ring with an insulating material.

[0012] Furthermore, this invention relates to a motor stator that is for either an AC motor or a DC motor.

[0013] Furthermore, this invention is a motor stator that further includes a cylindrical partition between the motor stator body and the substrate to separate the substrate from the motor coil end ring. [Effects of the Invention]

[0014] Regarding the connection of the neutral point of a three-phase induction motor, the conventional method involves soldering the ends of the A, B, C (or U, V, W) windings together and then insulating that portion. As a result, the connection portion becomes approximately twice the volume of the copper wire portion. Pushing this connection portion between the coil layers requires a lot of manual work, making automation impossible. This invention enables the electrical connection of the three copper wires by soldering the ends of the A, B, C (or U, V, W) windings onto copper foil installed on a circuit board. The motor stator of this invention uses a circuit board and secures soldering connections on the copper foil portion of the circuit board. This not only improves workability but also drastically reduces the occurrence of coil short circuits compared to the current method of pushing the neutral point and other connection portions between the coil layers (in AC three-phase induction motors). As a result, it enables improved reliability of AC motors using this invention, a reduction in initial defects in the manufacturing of motor stators, promotion of automation and labor saving, and reduction of personnel, cost reduction, and structural simplification. Furthermore, by adopting this technology in the electrification of automobiles, it is expected to contribute to respecting human life and reducing accidents. [Brief explanation of the drawing]

[0015] [Figure 1] Exploded perspective view of a three-phase induction motor using the motor stator of the present invention. [Figure 2] Cross-sectional view of the motor stator of the present invention [Figure 3] (a) A plan view of a compressor using the motor stator of this invention, and (b) A partial cross-sectional view of the line AA shown in the plan view. [Figure 4] This figure shows the circuit board of the motor stator of the present invention. [Figure 5]Figure showing another substrate of the motor stator of the present invention [Figure 6] (u) Figure showing the case when connecting to a motor using the substrate of FIG. 4, and (e) Figure showing the wiring of a three-phase induction motor [Figure 7] Figure showing the connection of a lead wire at a portion where a preliminary solder for power line connection is applied on the substrate of the motor stator of the present invention [Figure 8] (o) Figure showing the case when connecting to a motor using the substrate of FIG. 5 in the motor stator of the present invention, and (ka) Figure showing the wiring of a three-phase induction motor [Figure 9] (ki) Figure showing an extruded resin molding plate used for a partition for fixing the substrate of the motor stator of the present invention, and (ku) Plan view and side view of a partition manufactured by cutting the resin molding plate of (ki) to required dimensions and then processing it into a cylindrical shape [Figure 10] Circuit diagram of a motor coil with a three-phase 4-pole star connection and 12 slots [Figure 11] Plan view showing an example of inserting a copper wire coil into a stator core based on the coil circuit diagram of FIG. 10 [Figure 12] Plan view showing the coil layer of a stator using the coil circuit diagram of FIG. 10 [Figure 13] Circuit diagram of a motor coil with a three-phase 4-pole star connection and 24 slots [Figure 14] Figure showing the substrate of the motor stator of the present invention when using the coil circuit diagram of FIG. 13 [Figure 15] Figure showing the connection part of the end part of a coil in a three-phase 2-pole star connection [Figure 16] Explanatory diagram of a conventional method of pushing the neutral point of a three-phase star connection into the coil layer for shaping [Figure 17] Table showing a comparison when classifying conventional general motors according to the magnitude of output [Figure 18] Figure explaining that stress in a coil during shaping of a conventional motor coil causes a rare short circuit [[Embodiments for Carrying Out the Invention]]

[0016] The embodiments for carrying out the present invention will be described below with reference to the attached drawings, but these embodiments are merely examples shown for convenience in explanation, and the present invention is not limited in any sense to these embodiments. [Examples]

[0017] Figure 1 shows an exploded perspective view of a three-phase induction motor using the motor stator of the present invention, illustrating the general arrangement of the stator, circuit board, coil windings, and partitions of the present invention in the three-phase induction motor.

[0018] Figure 2 shows a cross-sectional view of the motor stator of the present invention. The stator is enclosed in a frame (22) made of iron, and a partition (12) is inscribed within the frame (22) and encloses the coil end ring of the stator, while supporting the substrate (9) at a position separated from the coil end ring. In other words, the partition is interposed between the stator and the substrate. The substrate (9) is fixed to the partition (12) with screws or the like. The substrate (9) is made of a common insulating material such as PET, and has multiple grooves and holes in its surface for passing coil wires through, and has continuous or discontinuous copper foil printing for soldering parts and wiring on the side opposite to the end ring of the stator. The partition is also made of a common insulating material such as PET, and as shown in Figure 9, in order to have a hollow cylindrical shape, it is made by forming a roughly rectangular flat plate with screw holes (42) into a cylindrical shape and then high-frequency welding the side ends that abut each other.

[0019] Figure 3 shows the stator section of the compressor, clearly illustrating the positional relationship between the stator, the partition, and the circuit board, which are press-fitted into the cylinder of the compressor body. The circuit board surface also shows the neutral points A', B', and C', which are the solder points to the copper foil printed wiring, as well as A, B, and C (or U, V, and W), which are the connection points to the power supply at the end of the coil.

[0020] Motors come in various types, differing in the number of poles, single-phase, three-phase, and the number of slots in the stator core. These differences in type result in various groove and hole positions on the circuit board for passing the coil copper wires (soldering points). Figure 4 shows a circuit board for a motor stator, illustrating the application of printed copper foil for neutral point connection and pre-soldering for power line connection in a 4-pole star-connected 12-slot three-phase induction motor, along with grooves at the coil end positions. Regarding the printed copper foil, for the short-circuit wires for the three-phase neutral points and connection points A, B, and C to the power supply, applying printed copper foil for soldering at both ends of the holes and pre-soldering improves work efficiency. Insulating resist printing is applied to the copper foil areas other than those to be soldered, such as the neutral point short-circuit wires. The grooves and holes on the circuit board are located at the connection points at the coil ends, and the copper wires for connection are secured to the holes by passing them through the grooves provided on the outer perimeter of the circuit board. Furthermore, by providing a small radius at the intersection of the outer circumference and the groove, insertion of the copper wire becomes easier, which helps automate the assembly process of passing the coil winding through the holes drilled in the circuit board. In other words, drilling holes in the circuit board and passing copper wire through requires manual work, which is inefficient. Therefore, as in this invention, by creating groove-shaped cuts in the circuit board, inserting the copper wire through these groove-shaped cuts, and fixing the copper wire in the holes, work efficiency is improved.

[0021] Figure 5 shows an example of a three-phase induction motor with a 4-pole star connection, 12 slots, and a copper-foil-free substrate for neutral point shorting. In relation to the substrate shown in Figure 4, it shows a copper-foil-free substrate without the neutral point shorting line, and the position of the coil ends is the same as in Figure 4.

[0022] Figure 6(u) shows an example where the substrate from Figure 4 is mounted on a stator, and there are no neutral point solder points A', B', C' at the coil ends on the substrate surface, nor are there any connections to the power supply A, B, C (or U, V, W). Instead, the connections are shown as a-phase, b-phase, and c-phase connections at the ends of the copper wires. Figure 6(e) shows a three-phase star connection. Small circles indicate connections, and similarly, connections are shown in each of the following figures.

[0023] Figure 7 shows an example of conductive connections made at power supply connection points A, B, and C on the circuit board, illustrating that lead wires were connected to the pre-soldered areas for power line connections on the circuit board of the motor stator of this invention.

[0024] Figure 8(o) corresponds to the coil end when the circuit board in Figure 5 is mounted on the stator, except that the printed copper foil wiring section, which is the neutral point shorting wire, is absent on the circuit board surface, and a crimp terminal is used for the neutral point connection. Also, this figure shows the coil end wire section fixed with adhesive using insulating material. The connection to the power supply is the same as in Figure 6. Figure 8(k) shows a three-phase star connection. The circles indicate the connection points.

[0025] Figure 9(ki) shows a flat (or long) extruded product for use as a partition. Figure 9(ku) shows a partition made by cutting the extruded product from Figure 9(ki) to the required dimensions and then processing it into a cylindrical shape (ultrasonic welding) for use as a motor stator. PET resin is the optimal material for this, and there are no problems in terms of insulation performance and mechanical strength.

[0026] Figure 10 is a coil circuit diagram of a 12-slot, 4-pole star-connected three-phase induction motor. A, B, C and A', B', C' are the connection points mentioned above.

[0027] Figure 11 is a diagram created based on the coil circuit diagram in Figure 10, showing the coil mounting state, the connecting wires between each coil, and the connections to the neutral point and power supply when a conventional copper wire coil is inserted and installed in a stator core (a stacked cylindrical body made of iron hollow discs).

[0028] Figure 12 is a top view of the coil layer when a copper wire coil, created based on the coil circuit diagram in Figure 10, is inserted into the stator core.

[0029] Figure 13 is a coil circuit diagram of a 4-pole star-connected 24-slot three-phase induction motor.

[0030] Figure 14 is a diagram specifically showing the connection states A', B', C' of the neutral point of the circuit board of the present invention used in a 4-pole star-connected 24-slot motor of a three-phase induction motor, and the state of the coil ends of the power supply connection points A, B, C (or U, V, W).

[0031] Figure 15 is a diagram illustrating the specific winding state of a two-pole star-connected coil in a three-phase induction motor. A and A' indicate the coil ends, and O indicates the neutral point. The beginning and end of the coil winding are the connection points. Note that the two phases B, B' and C, C' are in exactly the same state and have therefore been omitted.

[0032] Figure 16 shows the shaping state of a conventional three-phase induction motor coil by inserting the neutral point connection between the coil layers. It shows the state after inserting the neutral point connection between the coil layers and then processing it with a shaping press. Furthermore, since the neutral point connection is insulated after soldering, it becomes bulky, putting stress on the area around the coil layers. Also, the connection is completely invisible externally, making the coil end look aesthetically pleasing.

[0033] Figure 17 is a table showing the characteristics of conventional motor specifications when motor output is divided into high and low categories. As can be seen from this table, in the insertion process between coil layers of the neutral point connection of conventional coils, the probability of rare short circuits is generally higher as the output increases.

[0034] Figure 18 is a diagram illustrating the cause of rare short-circuit failure when compressive stress occurs in the coil copper wire. Applying localized pressure to the copper wire causes indentations, reducing the cross-sectional area of ​​the copper wire and thinning the insulating coating. The reduction in cross-sectional area leads to an increase in current density, causing localized heat generation in that area. This heat generation leads to thermal degradation of the insulating coating and a decrease in insulation resistance. Ultimately, the insulating coating burns out, causing a rare short circuit and motor shutdown. As mentioned above, stress on the copper wire greatly affects reliability. Due to the shaping process explained in Figure 16, the extent of deformation of the copper wire cannot be seen from the outside and therefore cannot be judged. In the industry, there are rare short-circuit testing machines as an inspection method, but they can only detect a complete break or short circuit.

[0035] This invention is suitably applicable to AC motors, single-phase induction motors, three-phase induction motors, synchronous motors using magnets in the rotor, inverter-controlled AC motors, DC motors for electric vehicles (EVs), and the like. [Explanation of Symbols]

[0036] 1. Stator (finished product) 2 Stator windings, coil layers 3 Intercooled layers 4. Neutral point connection 5 coil ends 6 Lead wires 7. Stator slot section (groove section in the stator for housing copper wire coils) 8-slot insulating paper 9 circuit boards 10. Teeth of the stator core 11. Stator core back (The annular portion that forms the outer circumference of the stator core forms the magnetic path.) 12. Screen for positioning circuit boards 13 Screws for securing the partition 14. Resist printing on the printed copper foil portion of the circuit board. 15. Solder joints on the circuit board 16 Holes for securing the screen 17. Grooves on the substrate through which copper wires pass. 18 Holes for fixing copper wires on the circuit board 19. Rotor 20 ball bearings 21 Shaft 22 Stator Frame 23 Eyelet rubber 24 brackets 25 Tightening bolts 26 Washers, nuts 27 Flag terminals 28. Insulating materials that protect conductive parts such as insulating tape and insulating tubes. 29. Adhesive (such as silicone resin) for fixing copper wires, etc., to the circuit board. 30 Three phase power supply 31. Starting point of the coil 32 End of coil winding 33. Coil wires 34. Compressor terminal box 35 Accumulator 36. Compressor terminal connection 37. Thickness of copper wire insulation 38. Pressure indicator arrow 39. Indentations in copper wire 40 Copper wire section stressed by shaping press 41 Reinforcement part of the partition 42 Screw holes in the screen 43 Reduced coating thickness of copper wire 44 Stator core metal plate Slot number 45 46. ​​Lead wire exit 47 Crimp terminals 48 Coil Symbol 49 High frequency welding part A(U) Coil end (connection part) B(V) coil end (connection point) C(W) coil end (connection point) O neutral point A' Coil end (connection point where the coil winding ends) B' Coil end (connection point where the coil winding ends) C' Coil end (connection point where the coil winding ends) a. Connection to the power supply b-phase power supply connection c-phase power supply connection

Claims

1. A motor stator characterized by mounting a substrate at a distance from the motor coil end ring protruding from the motor stator body, providing grooves and holes in the substrate for passing a plurality of motor coil windings through, and electrically connecting the ends of the winding ends of the plurality of motor coil windings to the surface of the substrate opposite to the surface facing the motor coil end ring.

2. The motor stator according to claim 1, wherein the ends of the winding ends of the plurality of motor coil windings are electrically connected by soldering using copper foil that has been continuously printed on the surface of the substrate opposite to the surface facing the motor coil end ring.

3. The motor stator according to claim 1 or claim 2, wherein the grooves and holes of the substrate position the winding end portions of the plurality of motor coil windings.

4. The motor stator according to claim 1, wherein the ends of the winding ends of the plurality of motor coil windings are electrically connected to a single end on the surface of the substrate opposite to the surface facing the motor coil end ring, and the plurality of motor coil windings are adhesively fixed to the surface of the substrate opposite to the surface facing the motor coil end ring with an insulating material.

5. The motor stator according to claim 1 or claim 2, wherein the motor stator is for an AC motor or a DC motor.

6. Furthermore, the motor stator according to claim 1 or claim 2, wherein a cylindrical partition is provided between the motor stator body and the substrate to separate the substrate from the motor coil end ring.

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