Motor and compressor

Abstract

This motor comprises: a rotor; an annular stator which is disposed on the outer circumferential side of the rotor; and a plurality of winding parts which are disposed side by side along the circumferential direction of the stator and around which conducting wires are wound. When n is defined as an integer greater than or equal to 3, each of three phases has an n number of winding parts. Each of the three phases forms a delta connection having three connection parts (51). When one connection part (51) which connects conducting wires (46) extending from two winding parts that are adjacent to each other in the circumferential direction of the stator is defined as an adjacent connection part (51A), and one connection part (51) which connects conducting wires (46) extending from two winding parts that are not adjacent to each other in the circumferential direction of the stator is defined as a non-adjacent connection part (51B), the three connection parts (51) include the non-adjacent connection part (51B) and the number of adjacent connection parts (51A) is 1 or 0.

Description

Motor and Compressor

[0001] The present invention relates to a motor and a compressor.

[0002] Star connection (Y connection) and delta connection (Δ connection) are known as connection methods for three-phase motors. Some motors of this type include a plurality of winding portions (coils) arranged side by side along the circumferential direction of an annular stator, with conductive wires wound around the winding portions.

[0003] Japanese Patent No. 7314968 Specification

[0004] In delta connection, each of the three phases is connected through three connection portions. When the voltage of each phase becomes unbalanced, there is a problem that a circulating current that circulates through the three connection portions is generated. In a motor, the generation of circulating current increases torque ripple, leading to increased vibration and noise.

[0005] The disclosed technology has been made in view of the above, and an object thereof is to provide a motor and a compressor capable of suppressing circulating current generated in delta connection.

[0006] One aspect of the motor disclosed in the present application includes a rotor, an annular stator arranged on an outer circumferential side of the rotor, and a plurality of winding portions arranged side by side along the circumferential direction of the stator with conductive wires wound therearound, wherein n is an integer of 3 or more, each of the three phases has n winding portions, and each of the three phases forms a delta connection having three connection portions. When one connection portion to which respective conductive wires extending from two winding portions adjacent in the circumferential direction of the stator are connected is defined as an adjacent connection portion, and one connection portion to which respective conductive wires extending from two winding portions not adjacent in the circumferential direction of the stator are connected is defined as a non-adjacent connection portion, the three connection portions include a non-adjacent connection portion, and the number of adjacent connection portions is 1 or 0.

[0007] According to one aspect of the motor disclosed in the present application, circulating current generated in delta connection can be suppressed.

[0008] Figure 1 is a longitudinal cross-sectional view showing a compressor equipped with the motor of Example 1. Figure 2 is a plan view showing the motor of Example 1 from the upper insulator side. Figure 3 is a bottom view showing the stator core in Example 1. Figure 4 is a schematic perspective view showing the insulator in Example 1. Figure 5 is a top view showing the stator in Example 1. Figure 6 is a wiring diagram showing the connection state of the windings of each phase in Example 1. Figure 7 is a schematic diagram for explaining the windings connected by three connection points in Example 1. Figure 8 is an exploded view for explaining the connecting paths of the windings forming each winding of each phase in Example 1. Figure 9 is a wiring diagram showing the connection state of the windings of each phase in the comparative example. Figure 10 is a schematic diagram for explaining the three connection points in the comparative example. Figure 11 is an exploded view for explaining the connecting paths of the windings forming each winding of each phase in the comparative example. Figure 12 is a diagram showing the relationship between frequency and current value in Example 1 and the comparative example. Figure 13 is a wiring diagram showing the connection state of the windings of each phase in Example 2. Figure 14 is a schematic diagram illustrating the windings connected by three connection points in Example 2. Figure 15 is an exploded view illustrating the routing of the windings forming each winding of each phase in Example 2. Figure 16 is a wiring diagram showing the connection state of the windings of each phase in Example 3. Figure 17 is a schematic diagram illustrating the windings connected by three connection points in Example 3. Figure 18 is an exploded view illustrating the routing of the windings forming each winding of each phase in Example 3.

[0009] The embodiments of the motor and compressor disclosed in this application will be described in detail below with reference to the drawings. However, the motor and compressor disclosed in this application are not limited by the embodiments described below.

[0010] Figure 1 is a longitudinal cross-sectional view showing a compressor equipped with a motor according to Embodiment 1. As shown in Figure 1, the compressor 1 is a so-called rotary compressor and comprises a container 2, a shaft 3, a compression unit 5, and a motor 6. The container 2 is made of a metal material and forms a sealed internal space 7. The internal space 7 is generally cylindrical. When the container 2 is placed vertically on a horizontal plane, the central axis of the internal space 7 is formed parallel to the vertical direction. An oil reservoir 8 is formed in the lower part of the internal space 7 of the container 2. Lubricating oil for lubricating the compression unit 5 is stored in the oil reservoir 8. The container 2 is connected to an intake pipe 11 for drawing in refrigerant and a discharge pipe 12 for discharging compressed refrigerant. The shaft 3 is provided along the vertical direction and is positioned in the internal space 7 of the container 2 such that one end is immersed in the oil reservoir 8. The shaft 3 is supported by the container 2 so as to be rotatable around the central axis of the internal space 7. The shaft 3 rotates, supplying the lubricating oil stored in the oil reservoir 8 to the compression section 5.

[0011] The compression section 5 is located in the lower part of the internal space 7 and above the oil reservoir 8. The compressor 1 further includes an upper muffler cover 14 and a lower muffler cover 15. The upper muffler cover 14 is located above the compression section 5 in the internal space 7. The upper muffler cover 14 forms an upper muffler chamber 16 inside it. The lower muffler cover 15 is located below the compression section 5 in the internal space 7 and above the oil reservoir 8. A lower muffler chamber 17 is formed inside the lower muffler cover 15. The lower muffler chamber 17 communicates with the upper muffler chamber 16 via a connecting passage (not shown) formed in the compression section 5. A discharge hole 18 for discharging compressed refrigerant is formed between the upper muffler cover 14 and the shaft 3, and the upper muffler chamber 16 communicates with the internal space 7 via the discharge hole 18.

[0012] The compression unit 5 compresses the refrigerant supplied from the intake pipe 11 by the rotation of a shaft 3 driven by a motor 6, and supplies the compressed refrigerant to the upper muffler chamber 16 and the lower muffler chamber 17. The refrigerant is compatible with lubricating oil.

[0013] Figure 2 is a plan view of the motor 6 of Embodiment 1, taken from the upper insulator side. As shown in Figures 1 and 2, the motor 6 is a three-phase motor and comprises a rotor 21 and a stator 22. The motor 6 is located above the compression section 5 within the internal space 7.

[0014] The rotor 21 is formed in a cylindrical shape by laminating multiple thin sheets of silicon steel, which is a magnetic material, and is integrated by multiple rivets 9. The rotor 21 is fixed to a shaft 3 inserted through the center of the rotor 21. The rotor 21 has six slit-shaped magnet embedding holes 10a formed so as to form the sides of a hexagon with the shaft 3 as the center. Each magnet embedding hole 10a is formed at a predetermined interval in the circumferential direction of the rotor 21. Plate-shaped permanent magnets 10b are embedded in the magnet embedding holes 10a. As a result, the rotor 21 has six magnetic pole portions 13 arranged in the circumferential direction of the stator 22.

[0015] The stator 22 is formed in a generally cylindrical shape, is positioned on the outer circumference of the rotor 21 so as to surround the rotor 21, and is fixed to the container 2. The stator 22 comprises a stator core 23, a lower insulator 25B as a first insulator, an upper insulator 25A as a second insulator, and a plurality of windings 46.

[0016] The upper insulator 25A is positioned at the upper end of the stator core 23 in the axial direction of the shaft 3. The lower insulator 25B is positioned at the lower end of the stator core 23 in the axial direction of the shaft 3. The upper insulator 25A and the lower insulator 25B are examples of insulating parts that insulate the stator core 23 from the windings 46. In this embodiment, the upper insulator 25A and the lower insulator 25B are formed to be the same shape, and are used as the upper insulator 25A when provided at the upper end of the stator core 23, and as the lower insulator 25B when provided at the lower end of the stator core 23. Hereinafter, in this embodiment, the upper insulator 25A and the lower insulator 25B together will be referred to as the insulator 25.

[0017] Figure 3 is a bottom view showing the stator core 23 in Embodiment 1. The stator core 23 is formed by laminating a plurality of metal plates made of a soft magnetic material, such as silicon steel sheets, and as shown in Figure 3, it comprises a yoke portion 31 and a plurality of stator core teeth portions 32-1 to 32-9. The yoke portion 31 is formed in a generally annular (cylindrical) shape. The first stator core tooth portion 32-1 of the plurality of stator core teeth portions 32-1 to 32-9 is formed in a generally columnar shape that extends in the radial direction of the stator core 23. The first stator core tooth portion 32-1 is formed with one end connected to the inner circumferential surface of the yoke portion 31, that is, it is formed to protrude radially inward from the inner circumferential surface of the yoke portion 31. Among the multiple stator core teeth portions 32-1 to 32-9, the stator core teeth portions 32-2 to 32-9, which are different from the first stator core teeth portion 32-1, are formed in a generally columnar shape, similar to the first stator core teeth portion 32-1, and protrude from the inner circumferential surface of the yoke portion 31. In the case of a 9-slot stator 22, the multiple stator core teeth portions 32-1 to 32-9 are formed on the inner circumferential surface of the yoke portion 31 so as to be arranged at equal intervals of 40° with respect to the circumferential direction of the yoke portion 31.

[0018] Figure 4 is a schematic perspective view of the insulator 25 in Embodiment 1. As shown in Figure 4, the insulator 25 (upper insulator 25A and lower insulator 25B) is formed in an annular shape from an insulator exemplified by polybutylene terephthalate resin (PBT). As shown in Figure 4, the insulator 25 has an annular outer peripheral wall portion 41, a plurality of insulator teeth portions 42-1 to 42-9 around which the winding wire (conductor) 46 is wound, and a plurality of flange portions 43-1 to 43-9. The outer peripheral wall portion 41 is formed in a generally cylindrical shape. The outer peripheral wall portion 41 has a plurality of slits 44 that extend from one end in the direction along the central axis of the outer peripheral wall portion 41 (the axial direction of the shaft 3) and are spaced apart in the circumferential direction of the outer peripheral wall portion 41. Furthermore, the other end of the outer peripheral wall portion 41, in the direction along the central axis of the outer peripheral wall portion 41, is in contact with the stator core 23. In other words, the multiple slits 44 are formed extending toward the stator core 23 from one end of the outer peripheral wall portion 41 opposite to the stator core 23. As the winding wire 46 drawn out from the winding portion 45, which will be described later, passes through each slit 44, the winding wire 46 drawn out from the inner circumference side to the outer circumference side of the outer peripheral wall portion 41 forms a connecting wire 49 stretched along the outer peripheral surface of the outer peripheral wall portion 41. Note that the insulator 25 shown in Figure 3 schematically shows the shape and arrangement of each slit 44 of the outer peripheral wall portion 41, and the details of the shape and arrangement of each slit 44 will be described later.

[0019] The first insulator tooth portion 42-1 of the multiple insulator tooth portions 42-1 to 42-9 is formed in the shape of a straight column with a cross-section that is approximately semicircular. One end of the first insulator tooth portion 42-1 is formed to be continuous with the inner surface of the outer peripheral wall portion 41, that is, it is formed to protrude from the inner surface of the outer peripheral wall portion 41. The insulator tooth portions 42-2 to 42-9, which are different from the first insulator tooth portion 42-1, are also formed in the same straight column shape as the first insulator tooth portion 42-1, and are formed to protrude from the inner surface of the outer peripheral wall portion 41. The multiple insulator tooth portions 42-1 to 42-9 are formed on the inner surface of the outer peripheral wall portion 41, arranged at equal intervals of 40 degrees with respect to the circumferential direction of the outer peripheral wall portion 41.

[0020] Multiple flange portions 43-1 to 43-9 correspond to multiple insulator tooth portions 42-1 to 42-9, and each is formed in a generally semicircular plate shape. The first flange portion 43-1, which corresponds to the first insulator tooth portion 42-1 among the multiple flange portions 43-1 to 43-9, is formed integrally with the first insulator tooth portion 42-1, and is continuous with the other end of the first insulator tooth portion 42-1. Similarly to the first flange portion 43-1, flange portions 43-1 to 43-9 that are different from the first flange portion 43-1 are also formed integrally with each of the multiple insulator tooth portions 42-1 to 42-9, and are continuous with the other end of the multiple insulator tooth portions 42-1 to 42-9.

[0021] Figure 5 is a top view showing the stator 22 in Embodiment 1, and is a view of the stator 22 from the upper insulator 25A side, in other words, from the lead side, which is the side in the axial direction of the shaft 3 where the power lines (lead wires) are arranged. As shown in Figure 4, each of the multiple stator core teeth 32-1 to 32-9 of the stator core 23 is wound with multiple windings 46 (U-phase windings 46-U1 to 46-U3, V-phase windings 46-V1 to 46-V3, and W-phase windings 46-W1 to 46-W3, which will be described later). Each of the stator core teeth 32-1 to 32-9 has a winding section 45 formed by the windings 46 of each phase. The nine winding sections 45 are indicated by the numbers 1 to 9 in counterclockwise order in Figure 5. The nine winding sections 45 are arranged along the circumferential direction of the stator core 23 so that the three phases repeat the same order. In other words, the U phase, V phase, and W phase are arranged in a counterclockwise order as shown in Figure 5.

[0022] The motor 6 in Embodiment 1 is a 6-pole, 9-slot concentrated winding type motor. The multiple windings (conductors) 46 include multiple U-phase windings 46-U1 to 46-U3 that form the U-phase winding section 45, multiple V-phase windings 46-V1 to 46-V3 that form the V-phase winding section 45, and multiple W-phase windings 46-W1 to 46-W3 that form the W-phase winding section 45.

[0023] The motor of the present invention has n windings 45 in each of its three phases, where n is an integer of 3 or more. Therefore, the motor of the present invention is not limited to 9 slots, and the number of slots, i.e., the number of windings 45 (or the number of stator core teeth 32), may be 12 or more and a multiple of 3. In other words, the number of insulator teeth 42 of the insulator 25 may be 9 or more and a multiple of 3.

[0024] (Wiring structure of the three-phase winding section) Figure 6 is a wiring diagram showing the wiring state of the winding section 45 of each phase in Embodiment 1. In Figure 6, each winding section 45 formed by winding the winding wire 46 around each of the nine stator core teeth sections 32-1 to 32-9 is indicated by the reference numerals [1] to [9] corresponding to Figure 5 and Figures 7 and 8 described later. Figure 7 is a schematic diagram for explaining the winding section 45 connected by three connection sections 51 in Embodiment 1. Figure 7 is a view from the lead side.

[0025] Figure 8 is an unfolded view illustrating the connecting paths of the windings 46 that form each winding portion 45 of each phase in Embodiment 1. In Figure 8, the upper part of the paper is the anti-lead side, which is opposite to the lead side in the axial direction of the shaft 3, and the lower part of the paper is the lead side. In Figure 8, the starting end of the winding 46 that begins winding the three winding portions 45 of each phase is indicated by a circle, and the ending end of the winding 46 that finishes winding the three winding portions 45 of each phase is indicated by a triangle. Figure 8 is an unfolded view of each winding portion 45 as seen from the inner circumference side of the yoke portion 31 along the radial direction of the yoke portion 31 (the radial direction of the outer peripheral wall portion 41 of the insulator 25). In Figure 8, as seen from the inner circumference side of the lower insulator 25B, the portion of the connecting wire 49 that is hidden on the outer peripheral side of the lower insulator 25B is indicated by a dotted line. On the other hand, when viewed from the inner circumference side of the lower insulator 25B, the portion of the connecting wire 49 that is not hidden by the outer circumference side of the lower insulator 25B (the portion of the connecting wire 49 that is visible through the slit 44) is shown by a solid line. As shown in Figure 8, the winding portion 45 of each phase is formed by winding the winding wire (conductor) 46 in a counterclockwise direction (CCW).

[0026] As shown in Figure 6, in the motor 6 of Embodiment 1, each of the three phases forms a delta connection with three connection points 51. Each of the U, V, and W phases has a series connection point 52 formed by the series connection of three windings 45, and the three series connection points 52 are electrically connected by three connection points 51. Each connection point 51 is formed by twisting together and connecting connecting wires, which will be described later and form part of the winding 46.

[0027] The series connection section 52 of the delta connection allows for a thinner wire diameter of the winding 46 compared to the series connection section of the star connection, and the number of turns in the winding section 45 can be reduced compared to the parallel connection section of the star connection. This makes it possible to reduce both wire diameter and the number of turns, thus increasing the space factor of the winding 46 while maintaining the productivity of the motor 6. In addition, since the delta connection does not have a neutral point like the star connection, heat generation at the neutral point can be avoided. Furthermore, since the delta connection does not require crimping parts or the like to form a neutral point like the star connection, manufacturing costs can be reduced.

[0028] Each connection point 51 is a portion where a winding start connection wire 54S, which is the end of a winding 46 located on the side where the three winding sections 45 of one phase begin to wind, and a winding end connection wire 54E, which is the end of a winding 46 located on the side where the three winding sections 45 of another phase end to wind, are electrically connected. Of the two connection wires, the winding start connection wire 54S and the winding end connection wire 54E, which are electrically connected at each connection point 51, one of them, for example, the winding start connection wire 54S, becomes the power line connected to the power supply.

[0029] (Motor Features) Next, the characteristic structure of the motor 6 of this embodiment will be described. Features of this embodiment include the connection structure of the three connection sections 51 in the delta connection, and for example, the arrangement of two winding sections 45 with different phases connected at each connection section 51 in the circumferential direction of the stator 22.

[0030] As shown in Figure 6, the motor 6 of Embodiment 1 has a delta connection 53 in which each phase has three winding sections 45. The delta connection 53 has a series connection section 52-U of the U phase consisting of a first winding section [1], a fourth winding section [4], and a seventh winding section [7], a series connection section 52-V of the V phase consisting of a fifth winding section [5], an eighth winding section [8], and a second winding section [2], and a series connection section 52-W of the W phase consisting of a third winding section [3], a sixth winding section [6], and a ninth winding section [9].

[0031] As shown in Figures 6 and 8, the series connection section 52-U of the U phase has windings 46 wound in the order of the first winding section [1], the fourth winding section [4], and the seventh winding section [7], with the end extending toward the first winding section [1] being the U phase winding start connection wire 54S-U, and the end extending from the seventh winding section [7] being the U phase winding end connection wire 54E-U.

[0032] In the V-phase series connection section 52-V, the windings 46 are wound in the order of the fifth winding section [5], the eighth winding section [8], and the second winding section [2], with the end extending toward the fifth winding section [5] being the V-phase winding start connection line 54S-V, and the end extending from the second winding section [2] being the V-phase winding end connection line 54E-V.

[0033] The series connection section 52-W of the W phase has the windings 46 wound in the order of the third winding section [3], the sixth winding section [6], and the ninth winding section [9], with the end extending toward the third winding section [3] being the W phase winding start connection wire 54S-W, and the end extending from the ninth winding section [9] being the W phase winding end connection wire 54E-W.

[0034] In this disclosure, when one connection section 51 to which each winding (conductor) 46 extending from two adjacent winding sections 45 in the circumferential direction of the stator 22 is connected is defined as an adjacent connection section 51A, and one connection section 51 to which each winding 46 extending from two non-adjacent winding sections 45 in the circumferential direction of the stator 22 is connected is defined as a non-adjacent connection section 51B, the three connection sections 51 include at least two non-adjacent connection sections 51B, and the number of adjacent connection sections 51A is 1 or 0.

[0035] As shown in Figures 7 and 8, the three connection sections 51 of the delta connection 53 in Embodiment 1 consist of two non-adjacent connection sections 51B and one adjacent connection section 51A. In Figure 8, each connection section 51 is formed by connecting a winding start connection wire 54S and a winding end connection wire 54E. In other words, the delta connection 53 in Embodiment 1 has a non-adjacent connection section 51B that electrically connects the seventh winding section [7] of the U phase and the third winding section [3] of the W phase with a U phase winding end connection line 54E-U and a W phase winding start connection line 54S-W, a non-adjacent connection section 51B that electrically connects the ninth winding section [9] of the W phase and the fifth winding section [5] of the V phase with a W phase winding end connection line 54E-W and a V phase winding start connection line 54S-V, and an adjacent connection section 51A that electrically connects the second winding section [2] of the V phase and the first winding section [1] of the U phase with a V phase winding end connection line 54E-V and a U phase winding start connection line 54S-U.

[0036] The two winding sections 45 of different phases connected at the adjacent connection section 51A generate magnetic flux when one winding section 45 is energized. This flux induces a voltage as it passes through the other adjacent winding section 45 in the circumferential direction of the stator 22, thereby increasing the magnetic flux coupling between the two stator core teeth sections 32 around which the two adjacent winding sections 45 are wound. Since the two stator core teeth sections 32 are adjacent and physically close to each other, magnetic flux is easily shared, and the mutual inductance tends to increase. In other words, at the adjacent connection section 51A, the coupling coefficient k between the adjacent winding sections 45 that are connected to each other increases as it approaches "1", and the mutual inductance between these adjacent winding sections 45 tends to increase. Here, a large mutual inductance means that when the magnetic flux changes in one of the two winding sections 45 connected at the adjacent connection section 51A, the magnetic flux that changes in this one winding section 45 easily passes through the other winding section 45, making it easier for an induced electromotive force to be generated in the other winding section 45 due to the change in magnetic flux. As a result of this large mutual inductance, the induced electromotive force generated in the other winding section 45 makes it easy for the three-phase voltages to become unbalanced, and this unbalanced voltage in each phase of the three-phase system makes it easy for the circulating current to become large.

[0037] On the other hand, in the non-adjacent connection section 51B, the physical distance between the two connected winding sections 45 is greater compared to the adjacent connection section 51A, thus keeping the mutual inductance small. In other words, in the non-adjacent connection section 51B, the coupling coefficient k between the two connected winding sections 45 becomes smaller, approaching "0", and the mutual inductance between the two connected winding sections 45 tends to be small. Here, small mutual inductance means that when the magnetic flux changes in one of the two winding sections 45 of different phases connected in the non-adjacent connection section 51B, the magnetic flux that changes in this one winding section 45 does not easily pass through the other winding section 45, so that an induced electromotive force due to the change in magnetic flux is less likely to occur in the other winding section 45. Therefore, because the mutual inductance is small and an induced electromotive force is less likely to occur in the other winding section 45, the three-phase voltage is less likely to become unbalanced, and the circulating current caused by the voltage imbalance of each phase in the three-phase system can be reduced.

[0038] From the above, it can be seen that the circulating current tends to be smaller in the non-adjacent connection section 51B compared to the adjacent connection section 51A. In other words, the fewer adjacent connection sections 51A there are among the three connection sections 51 (in other words, the more non-adjacent connection sections 51B there are), the smaller the circulating current tends to be. Therefore, in the embodiment, the number of adjacent connection sections 51A among the three connection sections 51 is set to one or zero to suppress the generation of circulating current. Embodiment 1 has only one adjacent connection section 51A and two non-adjacent connection sections 51B among the three connection sections 51. As a result, Embodiment 1, which has one adjacent connection section 51A, has one fewer adjacent connection section 51A (and one more non-adjacent connection section 51B) compared to the comparative example described later, which has two adjacent connection sections 51A. Therefore, the voltage of each phase of the delta connection 53 is less likely to become unbalanced, and the circulating current can be reduced. As a result, torque ripple generated by circulating current can be reduced, and the vibration and noise of the motor 6 can be decreased.

[0039] Furthermore, in Embodiment 1, of the two non-adjacent connection sections 51B, at least one non-adjacent connection section 51B has three or more winding sections 45 arranged between two winding sections 45 that are not adjacent in the circumferential direction of the stator 22, on the side where the distance between these two winding sections 45 along the circumferential direction of the stator 22 is shorter. In other words, between the seventh winding section [7] of the U phase and the third winding section [3] of the W phase, which are connected by the non-adjacent connection section 51B, there are three winding sections 45, namely the fourth winding section [4], the fifth winding section [5], and the sixth winding section [6]. Similarly, between the ninth winding section [9] of the W phase and the fifth winding section [5] of the V phase, which are connected by the non-adjacent connection section 51B, there are three winding sections 45, namely the sixth winding section [6], the seventh winding section [7], and the eighth winding section [8].

[0040] As a result, when the stator 22 is viewed from the axial direction of the shaft 3, an appropriate spatial distance is secured between the two winding sections 45 connected by the non-adjacent connection section 51B, allowing the coupling coefficient k to approach "0" more closely, and further reducing the mutual inductance between the two connected winding sections 45. Therefore, the generation of unintended induced electromotive forces due to changes in magnetic flux is suppressed between the two winding sections 45 connected by the non-adjacent connection section 51B, and the circulating current caused by the unbalanced voltage of the three phases in the delta connection 53 can be further reduced.

[0041] Furthermore, in Embodiment 1, there are two non-adjacent connection sections 51B, where three or more winding sections 45 are arranged between the two winding sections 45 connected by the non-adjacent connection section 51B. As a result, in each of the two non-adjacent connection sections 51B, the spatial distance is appropriately secured as described above, and the mutual inductance can be reduced, thereby further suppressing the circulating current generated in the delta connection 53.

[0042] Furthermore, the delta connection body 53 in Example 1 includes, as three winding start winding portions 45 corresponding to each of the three phases for starting winding of a winding 46 (conductive wire) around three winding portions 45 of each phase in the three phases, a U-phase first winding portion [1], a V-phase fifth winding portion [5], and a W-phase third winding portion [3] (hereinafter referred to as winding start winding portions 45). As shown in FIGS. 7 and 8, the three winding start winding portions, namely the U-phase first winding portion [1], the W-phase third winding portion [3], and the V-phase fifth winding portion [5], are arranged in the circumferential direction of the stator 22 such that one winding portion 45 other than the winding start winding portions 45 is interposed between each of the three winding start winding portions 45. That is, in the circumferential direction of the stator 22, a V-phase second winding portion [2] is arranged between the U-phase first winding portion [1] and the W-phase third winding portion [3], and a U-phase fourth winding portion [4] is arranged between the W-phase third winding portion [3] and the V-phase fifth winding portion [5].

[0043] (Comparative Example) A motor of a comparative example to be compared with the motor 6 of Example 1 will be described. In the comparative example, the same constituent members as those in Example 1 are denoted by the same reference numerals as those in Example 1.

[0044] FIG. 9 is a connection diagram showing a connection state of the winding portions 45 of each phase in the comparative example. FIG. 10 is a schematic diagram for explaining three connection portions 51 in the comparative example. FIG. 11 is a developed view for explaining a routing path of a winding 46 (cross-over wire 49) forming each winding portion 45 of each phase in the comparative example. In FIG. 11, the start end of the winding 46 at which winding of three winding portions 45 of each phase is started is indicated by a circle mark, and the end of the winding 46 at which winding of three winding portions 45 of each phase is completed is indicated by a triangle mark. The illustration method of the developed view in FIG. 11 is the same as that in FIG. 8, so a description thereof is omitted.

[0045] As shown in Figure 9, the comparative example motor, like the embodiment 1, has a delta connection 153 in which three winding sections 45 in each phase are connected in series. The delta connection 153 in the comparative example has a series connection section 52-U for the U phase consisting of the first winding section [1], the fourth winding section [4], and the seventh winding section [7], a series connection section 52-V for the V phase consisting of the fifth winding section [5], the eighth winding section [8], and the second winding section [2], and a series connection section 52-W for the W phase consisting of the third winding section [3], the sixth winding section [6], and the ninth winding section [9]. The comparative example differs from embodiment 1 in the arrangement of the series connection section 52-U for the U phase, the series connection section 52-V for the V phase, and the series connection section 52-W for the W phase, which are connected by three connection sections 51. In other words, the comparative example differs from Example 1 in that the winding portions 45 of each phase connected by the three connection portions 51 are different.

[0046] As shown in Figures 10 and 11, the three connection sections 51 of the delta connection 153 in the comparative example motor consist of one non-adjacent connection section 51B and two adjacent connection sections 51A. In other words, the delta connection 153 in the comparative example has a non-adjacent connection section 51B that electrically connects the seventh winding section [7] of the U phase and the fifth winding section [5] of the V phase with a U phase winding end connection line 54E-U and a V phase winding start connection line 54S-V, an adjacent connection section 51A that electrically connects the second winding section [2] of the V phase and the third winding section [3] of the W phase with a V phase winding end connection line 54E-V and a W phase winding start connection line 54S-W, and an adjacent connection section 51A that electrically connects the ninth winding section [9] of the W phase and the first winding section [1] of the U phase with a W phase winding end connection line 54E-W and a U phase winding start connection line 54S-U.

[0047] Therefore, compared to Example 1, the delta connection body 153 in the comparative example has one more adjacent connection portion 51A, and thus one less non-adjacent connection portion 51B. Further, in the circumferential direction of the stator 22, between the fifth winding portion [5] and the seventh winding portion [7] connected by the non-adjacent connection portion 51B in the comparative example, only one winding portion 45, which is the sixth winding portion [6], is interposed therebetween, and a sufficient spatial distance between the fifth winding portion [5] and the seventh winding portion [7] is not ensured. Therefore, compared to Example 1, the comparative example has one more adjacent connection portion 51A, resulting in a larger mutual inductance at the adjacent connection portion 51A. Further, compared to Example 1, in the comparative example, the number of winding portions 45 interposed between the two winding portions 45 (the fifth winding portion [5] and the seventh winding portion [7]) connected by the non-adjacent connection portion 51B is two less, resulting in a larger mutual inductance at the non-adjacent connection portion 51B.

[0048] FIG. 12 is a diagram showing the relationship between frequency and current value in Example 1 and the comparative example, and shows the result of fast Fourier transform (FFT) performed on the waveform of phase current when the rotational speed of the motor is 40 [rps]. In FIG. 12, the vertical axis represents the current value [A], and the horizontal axis represents the frequency [Hz]. In FIG. 12, Example 1 is shown by a solid line, and the comparative example is shown by a broken line.

[0049] As shown in FIG. 12, compared with the comparative example, in Example 1, the current value at a frequency of about 240 [Hz], which corresponds to the 3n-order harmonic of the motor and is surrounded by the encircling line C, is reduced. The 3n-order harmonic of the motor is called a "zero-phase component", and when the waveform of each phase in three-phase alternating current (U-phase, V-phase, W-phase) fluctuates in a state where the phase matches that of other phases, it remains as a third-order harmonic component in the current circuit. In the case of star connection (Y connection), the component is vectorially canceled through the neutral point, while in the case of delta connection (Δ connection), there is no neutral point, so the 3n-order harmonic component loops within the delta connection, and as a result, it is significantly affected by circulating current. Therefore, the reduction of the current value near 240 [Hz] corresponding to the 3n-order harmonic of the motor indicates that the generation of induced current is suppressed. From the above, compared with the comparative example, Example 1 can suppress the generation of induced current in the motor 6 and suppress torque ripple, so vibration and noise of the motor 6 can be reduced.

[0050] (Characteristics of the insulator) In the manufacturing process of the motor 6 in Embodiment 1, a winding machine (not shown) is used to supply winding wire 46 from a nozzle, wind the winding wire 46 across the stator core teeth 32-1 to 32-9 of the stator core 23 and the insulator teeth 42-1 to 42-9 of the upper insulator 25A and lower insulator 25B, and wind the winding wire 46 along the outer peripheral wall 41 of the upper insulator 25A and lower insulator 25B. In Embodiment 1, when forming each of the three winding sections 45 using the winding machine, a so-called three-nozzle winding method is applied, in which the operation of three nozzles is synchronized to form each of the three winding sections 45 simultaneously, and the winding sections 45 of each phase are wound in order to form the three winding sections 45.

[0051] As shown in Figures 6 and 8, each winding section 45 of the U phase is formed by winding one wire (conductor) 46 in the order of the first winding section [1], the fourth winding section [4], and the seventh winding section [7]. Each winding section 45 of the V phase is formed by winding one wire 46 in the order of the fifth winding section [5], the eighth winding section [8], and the second winding section [2]. Each winding section 45 of the W phase is formed by winding one wire 46 in the order of the third winding section [3], the sixth winding section [6], and the ninth winding section [9].

[0052] Multiple slits 44 are formed in the outer peripheral wall portion 41 of the insulator 25 to allow connecting wires 49 extending from multiple winding portions 45 to pass from the outer peripheral side to the inner peripheral side of the outer peripheral wall portion 41, or from the inner peripheral side to the outer peripheral side of the outer peripheral wall portion 41.

[0053] As shown in Figure 8, each slit 44 through which the connecting wire 49 connecting the three winding portions 45 of one phase in the three phases passes is provided such that the depth extending from one end to the other of the outer peripheral wall portion 41 of the lower insulator 25B, which is on the non-lead side in the axial direction of the shaft 4, decreases sequentially along the circumferential direction of the outer peripheral wall portion 41.

[0054] When each winding section 45 of the U-phase is formed in the order of the first winding section [1], the fourth winding section [4], and the seventh winding section [7], the winding wire (conductor) 46 and connecting wire 49 are passed through the slits 44A-U, slit 44B-U, slit 44C-U, and slit 44D-U of the lower insulator 25B on the non-lead side. The depth of each slit 44 used when forming each winding section 45 of the U-phase decreases in the circumferential direction of the outer peripheral wall section 41 in the order of slit 44A-U, slit 44B-U, slit 44C-U, and slit 44D-U.

[0055] Similarly, when each winding portion 45 of the V phase is formed in the order of the fifth winding portion [5], the eighth winding portion [8], and the second winding portion [2], the winding wire (conductor) 46 and connecting wire 49 are passed through the slits 44A-V, slit 44B-V, slit 44C-V, and slit 44D-V of the lower insulator 25B on the non-lead side. The depth of each slit 44 used when forming each winding portion 45 of the V phase decreases in the circumferential direction of the outer peripheral wall portion 41 in the order of slit 44A-V, slit 44B-V, slit 44C-V, and slit 44D-V.

[0056] Similarly, when each winding section 45 of the W phase is formed in the order of the third winding section [3], the sixth winding section [6], and the ninth winding section [9], the winding wire (conductor) 46 and connecting wire 49 are passed through the slits 44A-W, slit 44B-W, slit 44C-W, and slit 44D-W of the lower insulator 25B on the non-lead side. The depth of each slit 44 used when forming each winding section 45 of the W phase decreases in the circumferential direction of the outer peripheral wall section 41 in the order of slit 44A-W, slit 44B-W, slit 44C-W, and slit 44D-W.

[0057] In this way, multiple slits 44 (44A-U to 44D-U, 44A-V to 44D-V, 44A-W to 44D-W) are formed in the lower insulator 25B, making it possible to synchronize the operation of the three nozzles using the three-nozzle winding method and simultaneously form each of the three phase winding sections 45. Furthermore, by making the depths of the slits corresponding to each of the three phases (for example, 44A-U, 44A-V, and 44A-W) the same, the connecting wires 49 of each phase can be stretched parallel to each other on the outer surface of the outer wall portion 41, thus ensuring sufficient insulation distance between the connecting wires 49 of each phase without increasing the height of the outer wall portion 41 in the axial direction of the shaft 4. As a result, it is avoided that the lower insulator 25B will be enlarged in the axial direction of the shaft 4 in order to ensure the insulation distance. In addition, it is avoided that insulating material will need to be added between connecting wires 49 of different phases to insulate the connecting wires 49 of each phase.

[0058] In Figure 8, the depth of each slit 44 decreases in the circumferential direction of the outer wall portion 41 as you move towards the right in Figure 8, but this direction is not limited to this. The depth of each slit 44 may decrease in the outer wall portion 41 as you move towards the left in Figure 8.

[0059] (Effects of Example 1) As described above, in the motor 6 of Example 1, each of the three phases has n winding sections 45, where n is an integer of 3 or more, and each of the three phases forms a delta connection having three connection sections 51. When one connection section 51 to which each winding (conductor) 46 extending from two adjacent winding sections 45 in the circumferential direction of the stator 22 is connected is defined as an adjacent connection section 51A, and one connection section 51 to which each winding (conductor) 46 extending from two winding sections 45 that are not adjacent in the circumferential direction of the stator 22 is connected is defined as a non-adjacent connection section 51B, the three connection sections 51 include the non-adjacent connection section 51B, and the number of adjacent connection sections 51A is 1. As a result, the number of non-adjacent connection sections 51B and the number of adjacent connection sections 51A among the three connection sections 51 in the delta connection can be increased, thereby reducing the mutual inductance of the three connection sections 51 as a whole, and thus suppressing the circulating current generated in the delta connection. Consequently, the torque ripple of the motor 6 can be suppressed, and the vibration and noise of the motor 6 can be reduced.

[0060] Furthermore, in the motor 6 of Embodiment 1, at least one non-adjacent connection section 51B included in the three connection sections 51 has three or more winding sections 45 arranged between two winding sections 45 that are not adjacent in the circumferential direction of the stator 22, on the side where the distance between these two winding sections 45 along the circumferential direction of the stator 22 is shorter. As a result, when the stator 22 is viewed from the axial direction of the shaft 3, the spatial distance between the two winding sections 45 connected by the non-adjacent connection section 51B is appropriately secured, so that the mutual inductance between the two winding sections 45 can be further reduced. Therefore, the generation of unintended induced electromotive force due to changes in magnetic flux is suppressed between the two winding sections 45 connected by the non-adjacent connection section 51B, and the circulating current caused by the unbalanced three-phase voltage in the delta connection 53 can be further reduced.

[0061] Furthermore, in the motor 6 of Embodiment 1, the number of non-adjacent connection sections 51B, in which three or more winding sections 45 are arranged between the two winding sections 45 as described above, is two. As a result, in each of the two non-adjacent connection sections 51B, the spatial distance is appropriately secured as described above, and the mutual inductance can be reduced, thereby further suppressing the circulating current generated in the delta connection 53.

[0062] Furthermore, in the motor 6 of Embodiment 1, the outer peripheral wall portion 41 of the lower insulator 25B has a plurality of slits 44 formed therein for passing connecting wires 49 extending from a plurality of winding portions 45 from the outer peripheral side to the inner peripheral side of the outer peripheral wall portion 41, or from the inner peripheral side to the outer peripheral side of the outer peripheral wall portion 41. Each slit 44 (44A-U to 44D-U, 44A-V to 44D-V, 44A-W to 44D-W) through which the connecting wires 49 connecting the n winding portions 45 of one phase in the three phases pass is provided such that the depth extending from one end of the outer peripheral wall portion 41 to the other decreases sequentially along the circumferential direction of the outer peripheral wall portion 41. This makes it possible to synchronize the operation of the three nozzles using the three-nozzle winding method and simultaneously form each of the three winding portions 45 of the three phases. Furthermore, by making the depths of the corresponding slits (for example, 44A-U, 44A-V, and 44A-W) for each of the three phases the same, the connecting wires 49 for each phase can be stretched parallel to each other on the outer surface of the outer wall portion 41. This ensures sufficient insulation distance between the connecting wires 49 of each phase without increasing the height of the outer wall portion 41 in the axial direction of the shaft 4. As a result, it is avoided that the lower insulator 25B will need to be enlarged in the axial direction of the shaft 4 in order to secure the insulation distance. In addition, it is avoided that insulating material needs to be added between connecting wires 49 of different phases to insulate the connecting wires 49 of each phase.

[0063] Examples 2 and 3 will be described below with reference to the drawings. In Examples 2 and 3, components identical to those in Example 1 are given the same reference numerals and their descriptions are omitted. Examples 2 and 3 differ from Example 1 in that the winding portions 45 of each phase connected by the three connection portions 51 of the delta connection are different.

[0064] Figure 13 is a wiring diagram showing the connection state of the winding sections 45 of each phase in Embodiment 2. Figure 14 is a schematic diagram illustrating the winding sections 45 connected by three connection points 51 in Embodiment 2. Figure 15 is an unfolded diagram illustrating the connecting paths of the windings 46 (jumpers) forming each winding section 45 of each phase in Embodiment 2. In Figure 15, the starting point of the winding 46 that begins winding the three winding sections 45 of each phase is indicated by a circle (○), and the ending point of the winding 46 that finishes winding the three winding sections 45 of each phase is indicated by a triangle (△). The method of showing the unfolded diagram in Figure 15 is the same as in Figure 8, so it is omitted here.

[0065] As shown in Figure 13, the motor of Embodiment 2 has a delta connection 63 in which three winding sections 45 in each phase are connected in series. The delta connection 63 has a series connection section 52-U for the U phase consisting of a first winding section [1], a fourth winding section [4], and a seventh winding section [7], a series connection section 52-V for the V phase consisting of a second winding section [2], a fifth winding section [5], and an eighth winding section [8], and a series connection section 52-W for the W phase consisting of a third winding section [3], a sixth winding section [6], and a ninth winding section [9].

[0066] As shown in Figures 13 and 15, the series connection section 52-U of the U phase has windings 46 wound in the order of the first winding section [1], the fourth winding section [4], and the seventh winding section [7], with the end extending toward the first winding section [1] being the U phase winding start connection wire 54S-U, and the end extending from the seventh winding section [7] being the U phase winding end connection wire 54E-U.

[0067] In the V-phase series connection section 52-V, the windings 46 are wound in the order of the second winding section [2], the fifth winding section [5], and the eighth winding section [8], with the end extending toward the second winding section [2] being the V-phase winding start connection line 54S-V, and the end extending from the eighth winding section [8] being the U-phase winding end connection line 54E-V.

[0068] The series connection section 52-W of the W phase has the windings 46 wound in the order of the third winding section [3], the sixth winding section [6], and the ninth winding section [9], with the end extending toward the third winding section [3] being the W phase winding start connection wire 54S-W, and the end extending from the ninth winding section [9] being the W phase winding end connection wire 54E-W.

[0069] As shown in Figures 14 and 15, the three connection sections 51 of the delta connection 63 in Embodiment 2 consist of two non-adjacent connection sections 51B and one adjacent connection section 51A. In other words, the delta connection 63 in Embodiment 2 has a non-adjacent connection section 51B which electrically connects the seventh winding section [7] of the U phase and the second winding section [2] of the V phase with a U phase winding end connection line 54E-U and a V phase winding start connection line 54S-V, a non-adjacent connection section 51B which electrically connects the first winding section [8] of the V phase and the third winding section [3] of the W phase with a V phase winding end connection line 54E-V and a W phase winding start connection line 54S-W, and an adjacent connection section 51A which electrically connects the ninth winding section [9] of the W phase and the first winding section [1] of the U phase with a W phase winding end connection line 54E-W and a U phase winding start connection line 54S-U.

[0070] Therefore, in Example 2, similar to Example 1, there is only one adjacent connection section 51A and two non-adjacent connection sections 51B among the three connection sections 51. As a result, Example 1, which has one adjacent connection section 51A, has one fewer adjacent connection section 51A (and one more non-adjacent connection section 51B) compared to the comparative example described above, which has two adjacent connection sections 51A. This makes it less likely for the voltage of each phase of the delta connection 53 to become unbalanced, and the circulating current can be reduced. As a result, torque ripple generated by the circulating current can be reduced, and the vibration and noise of the motor 6 can be reduced.

[0071] Furthermore, in Embodiment 2, of the two non-adjacent connection sections 51B, at least one non-adjacent connection section 51B has three or more winding sections 45 arranged between two winding sections 45 that are not adjacent in the circumferential direction of the stator 22, on the side where the distance between these two winding sections 45 along the circumferential direction of the stator 22 is shorter. In other words, between the seventh winding section [7] of the U phase and the second winding section [2] of the V phase, which are connected by the non-adjacent connection section 51B, there are three winding sections 45, which are the eighth winding section [8], the ninth winding section [9], and the first winding section [1]. Similarly, between the third winding section [3] of the W phase and the eighth winding section [8] of the V phase, which are connected by the non-adjacent connection section 51B, there are three winding sections 45, which are the ninth winding section [9], the first winding section [1], and the second winding section [2].

[0072] As a result, when the stator 22 is viewed from the axial direction of the shaft 3, an appropriate spatial distance is secured between the two winding sections 45 connected by the non-adjacent connection section 51B, allowing the coupling coefficient k to approach "0" more closely, and further reducing the mutual inductance between the two connected winding sections 45. Therefore, the generation of unintended induced electromotive forces due to changes in magnetic flux is suppressed between the two winding sections 45 connected by the non-adjacent connection section 51B, and the circulating current caused by the unbalanced three-phase voltage in the delta connection 53 can be further reduced.

[0073] Furthermore, in Embodiment 2, there are two non-adjacent connection sections 51B, where three or more winding sections 45 are arranged between the two winding sections 45 connected by the non-adjacent connection section 51B, as described above. As a result, the spatial distance is appropriately secured in each of the two non-adjacent connection sections 51B, as described above, and the mutual inductance can be reduced, thereby further suppressing the circulating current generated in the delta connection 53.

[0074] Furthermore, in the delta connection 53 of Embodiment 2, in the three phases, there are three starting winding sections 45 corresponding to each of the three phases, where the winding wire 46 (conductor) begins to be wound around the three winding sections 45 of each phase: the first winding section [1] of the U phase, the second winding section [2] of the V phase, and the third winding section [3] of the W phase. The three starting winding sections 45, the first winding section [1] of the U phase, the second winding section [2] of the V phase, and the third winding section [3] of the W phase, are arranged adjacent to each other in the circumferential direction of the stator 22, as shown in Figures 14 and 15.

[0075] (Effects of Example 2) As described above, the motor of Example 2, like Example 1, has three connection sections 51 in the delta connection that include two non-adjacent connection sections 51B. By increasing the number of non-adjacent connection sections 51B and decreasing the number of adjacent connection sections 51A among the three connection sections 51 in the delta connection, the mutual inductance of the three connection sections 51 as a whole can be reduced, thereby suppressing the circulating current generated in the delta connection.

[0076] Figure 16 is a wiring diagram showing the connection state of the winding sections 45 of each phase in Embodiment 3. Figure 17 is a schematic diagram illustrating the winding sections 45 connected by three connection points 51 in Embodiment 3. Figure 18 is an unfolded diagram illustrating the connecting paths of the windings 46 (jumpers) forming each winding section 45 of each phase in Embodiment 3. In Figure 18, the starting point of the winding 46 that begins winding the three winding sections 45 of each phase is indicated by a circle (○), and the ending point of the winding 46 that finishes winding the three winding sections 45 of each phase is indicated by a triangle (△). The method of showing the unfolded diagram in Figure 18 is the same as in Figure 8, so it is omitted here.

[0077] As shown in Figure 16, the motor of Embodiment 3 has a delta connection 73 in which three winding sections 45 in each phase are connected in series. The delta connection 73 has a series connection section 52-U for the U phase consisting of a first winding section [1], a fourth winding section [4], and a seventh winding section [7], a series connection section 52-V for the V phase consisting of a second winding section [2], a fifth winding section [5], and an eighth winding section [8], and a series connection section 52-W for the W phase consisting of a third winding section [3], a sixth winding section [6], and a ninth winding section [9].

[0078] As shown in Figures 16 and 18, the series connection section 52-U of the U phase has windings 46 wound in the order of the first winding section [1], the fourth winding section [4], and the seventh winding section [7], with the end extending toward the first winding section [1] being the U phase winding start connection wire 54S-U, and the end extending from the seventh winding section [7] being the U phase winding end connection wire 54E-U.

[0079] In the V-phase series connection section 52-V, the windings 46 are wound in the order of the second winding section [2], the fifth winding section [5], and the eighth winding section [8], with the end extending toward the second winding section [2] being the V-phase winding start connection line 54S-V, and the end extending from the eighth winding section [8] being the U-phase winding end connection line 54E-V.

[0080] The series connection section 52-W of the W phase has the windings 46 wound in the order of the third winding section [3], the sixth winding section [6], and the ninth winding section [9], with the end extending toward the third winding section [3] being the W phase winding start connection wire 54S-W, and the end extending from the ninth winding section [9] being the W phase winding end connection wire 54E-W.

[0081] As shown in Figures 17 and 18, the three connection sections 51 of the delta connection 63 in Embodiment 3 consist of three non-adjacent connection sections 51B. That is, the delta connection 73 in Embodiment 3 has a non-adjacent connection section 51B that electrically connects the seventh winding section [7] of the U phase and the third winding section [2] of the W phase with a U phase winding end connection line 54E-U and a W phase winding start connection line 54S-W, a non-adjacent connection section 51B that electrically connects the first winding section [8] of the V phase and the first winding section [1] of the U phase with a V phase winding end connection line 54E-V and a U phase winding start connection line 54S-U, and a non-adjacent connection section 51B that electrically connects the ninth winding section [9] of the W phase and the second winding section [2] of the V phase with a W phase winding end connection line 54E-W and a V phase winding start connection line 54S-V.

[0082] Therefore, in Example 3, all three connection sections 51 are formed as non-adjacent connection sections 51B, and the number of adjacent connection sections 51A is "0". As a result, Example 3, which has 0 adjacent connection sections 51A, has 2 fewer adjacent connection sections 51A (and 2 more non-adjacent connection sections 51B) compared to the comparative example described above, where there are 2 adjacent connection sections 51A. This makes it less likely for the voltage of each phase of the delta connection 53 to become unbalanced, and the circulating current can be reduced. As a result, torque ripple generated by the circulating current can be reduced, and the vibration and noise of the motor 6 can be reduced.

[0083] Furthermore, in Embodiment 3, of the three non-adjacent connection sections 51B, at least one non-adjacent connection section 51B has three or more winding sections 45 arranged between two winding sections 45 that are not adjacent in the circumferential direction of the stator 22, on the side where the distance between these two winding sections 45 along the circumferential direction of the stator 22 is shorter. In other words, between the seventh winding section [7] of the U phase and the third winding section [3] of the W phase, which are connected by the non-adjacent connection section 51B, there are three winding sections 45, which are the fourth winding section [4], the fifth winding section [5], and the sixth winding section [6].

[0084] As a result, when the stator 22 is viewed from the axial direction of the shaft 3, an appropriate spatial distance is secured between the two seventh windings [7] and the third windings [3] connected by the non-adjacent connection section 51B, so that the coupling coefficient k can be brought closer to "0", and the mutual inductance between the two connected windings 45 (seventh winding [7] and third windings [3]) can be further reduced. Therefore, the generation of unintended induced electromotive forces due to changes in magnetic flux is suppressed between the two windings 45 connected by the non-adjacent connection section 51B, so that the circulating current caused by the unbalanced three-phase voltage in the delta connection 53 can be further reduced.

[0085] Furthermore, in the delta connection 53 of Embodiment 3, in the three phases, there are three starting winding sections 45 corresponding to each of the three phases, where the winding wire 46 (conductor) begins to be wound around the three winding sections 45 of each phase: the first winding section [1] of the U phase, the second winding section [2] of the V phase, and the third winding section [3] of the W phase. The three starting winding sections 45, the first winding section [1] of the U phase, the second winding section [2] of the V phase, and the third winding section [3] of the W phase, are arranged adjacent to each other in the circumferential direction of the stator 22, as shown in Figures 14 and 15.

[0086] (Effects of Example 3) As described above, in the motor of Example 3, the three connection sections 51 in the delta connection consist of three non-adjacent connection sections 51B. By increasing the number of non-adjacent connection sections 51B and decreasing the number of adjacent connection sections 51A, the mutual inductance of the three connection sections 51 as a whole can be reduced, thereby suppressing the circulating current generated in the delta connection.

[0087] In Examples 1 to 3, the winding portions 45 of each phase forming the delta connection were connected in series, but the connection is not limited to series, and the winding portions 45 of each phase may be connected in parallel. If each phase to be delta connected has, for example, four winding portions 45, two series connections of two winding portions 45 may be connected in parallel.

[0088] 1 Compressor 2 Vessel 5 Compression section 6 Motor 13 Magnetic pole section 21 Rotor 22 Stator 25 (25A, 25B) Insulator 41 Outer wall section (wall section) 44 (44A-U to 44D-U, 44A-V to 44D-V, 44A-W to 44D-W) Slit 45 Winding section 46 Winding wire (conductor) 49 Jumper wire (conductor) 51 Connection section 51A Adjacent connection section 51B Non-adjacent connection section 53, 63, 73 Delta connection

Claims

1. A motor comprising a rotor, an annular stator disposed on the outer circumference of the rotor, and a plurality of winding sections arranged in a line along the circumferential direction of the stator and around which conductors are wound, wherein each of the three phases has n winding sections, and each of the three phases forms a delta connection having three connection sections, and when one connection section formed by connecting the conductors extending from two adjacent winding sections of the stator in the circumferential direction is defined as an adjacent connection section, and one connection section formed by connecting the conductors extending from two winding sections that are not adjacent in the circumferential direction is defined as a non-adjacent connection section, the three connection sections include the non-adjacent connection sections, and the number of adjacent connection sections is 1 or 0.

2. The motor according to claim 1, wherein each of the three phases has three winding portions, and the rotor has six magnetic pole portions arranged in the circumferential direction.

3. The motor according to claim 1, wherein at least one of the three connection portions is a non-adjacent connection portion, and three or more winding portions are arranged between two winding portions that are not adjacent in the circumferential direction, on the side where the distance between the two winding portions along the circumferential direction is shorter.

4. The motor according to claim 3, wherein the number of at least one non-adjacent connection portion included in the three connection portions is two.

5. The motor according to claim 1, further comprising an insulator provided at the end of the stator and having an annular wall, wherein the wall has a plurality of slits formed therein for passing connecting wires extending from the plurality of winding portions from the outer circumference to the inner circumference of the wall, or from the inner circumference to the outer circumference of the wall, and each slit through which the connecting wires connecting the n winding portions of one phase of the three phases pass is provided such that the depth extending from one end of the wall to the other decreases sequentially along the circumferential direction of the wall.

6. The motor according to claim 5, wherein the n windings of each phase in the three phases are connected in series.

7. The motor according to claim 1, wherein the three phases include three starting winding sections corresponding to each phase of the three phases, where a conductor is to be wound around n winding sections of each phase, and the three starting winding sections are arranged adjacent to each other in the circumferential direction, or are arranged in the circumferential direction with one winding section other than the starting winding section sandwiched between each of the three starting winding sections.

8. A compressor comprising: a motor according to any one of claims 1 to 7; a compression unit driven by the motor; and a container in which the compression unit is provided.

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