Rotary electric machine and hoisting machine equipped with same

Abstract

The present invention provides a rotary electric machine in which a flat wire wound around the tooth of a stator can be stably held.　The rotary electric machine according to the present invention comprises: a stator 21; and a rotor 22 disposed with a gap with respect to the stator 21. The stator 21 includes: a stator core 210; a plurality of teeth 212 extending from the yoke 211 of the stator core 210 toward the rotor 22 side; and a coil 215 formed by being wound around each tooth 212 via a bobbin 214.　The coil 215 is constituted by: a lower layer (first layer) wound in the radial direction so that a flat wire 215a having a square cross section makes contact with the bobbin 214; and an upper layer (second layer) wound in the radial direction so as to overlap the lower layer.　One flat wire 215a (flat wire 2A) of the upper layer is disposed so as to straddle two adjacent flat wires 215a (flat wire 1A and flat wire 1B) of the lower layer.

Description

Rotating electric machine and hoist equipped with the same

[0001] The present invention relates to a rotating electric machine and a hoisting machine including the same.

[0002] In rotating electrical machines such as electric motors, windings are wound around the teeth of a stator via bobbins. In stators, rectangular wire with a square cross section is used for the windings to increase the space factor within the slots. The rectangular wire is wound around the teeth in the following manner: the first layer is wound in a line in the radial direction, the second layer is wound overlapping the first layer, and the third layer is wound overlapping the second layer. In other words, the rectangular wire is wound around the teeth in multiple layers in the circumferential direction.

[0003] The first layer of flat wire is wound so that it is aligned in the radial direction. When the second layer of flat wire is wound over the first layer of flat wire, it is wound so that it is aligned with the first layer of flat wire in the radial and circumferential directions. Similarly, when the third layer of flat wire is wound over the second layer of flat wire, it is wound so that it is aligned with the second layer of flat wire in the radial and circumferential directions. Then, the coil is formed by winding the flat wires aligned in the radial and circumferential directions around the teeth. An example of such a technology is described in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2008-148515

[0005] In order to wind the rectangular wires in a radially aligned manner, it is necessary to provide a predetermined gap between adjacent rectangular wires in the radial direction. The same applies to the second layer of rectangular wire laminated on the first layer of rectangular wire, and the third layer of rectangular wire laminated on the second layer.

[0006] Vibrations occur in rotating electric machines during operation. These vibrations are also transmitted to the coils, causing the flat wires wound around the teeth to unravel. In a structure such as that described in Patent Document 1, in which adjacent flat wires are arranged radially with a predetermined gap between them and the second and third layers of laminated flat wires are aligned circumferentially, the vibrations can cause adjacent flat wires to shift circumferentially, potentially causing the coil to unravel. To secure the flat wires together, the coils are sometimes varnished after the flat wires have been wound. However, this varnishing process is necessary, and if cracks or other defects occur in the varnish, the coil may unravel from the cracked areas.

[0007] An object of the present invention is to solve the above-mentioned problems and to provide a rotating electric machine that can stably hold rectangular wire wound around the teeth of a stator, and a hoist equipped with the same.

[0008] In order to achieve the above object, the present invention provides a rotating electric machine comprising a stator and a rotor arranged with a gap between them, the stator comprising a stator core, a plurality of teeth extending from the yoke of the stator core toward the rotor side, and a coil wound around the teeth via a bobbin, wherein the coil is composed of a lower layer in which a rectangular wire with a square cross section is wound radially so as to contact the bobbin, and an upper layer in which the rectangular wire is wound radially so as to overlap the lower layer, and one rectangular wire of the upper layer is arranged so as to straddle two adjacent rectangular wires of the lower layer.

[0009] According to the present invention, it is possible to provide a rotating electric machine that can stably hold a rectangular wire wound around the teeth of a stator, and a hoist equipped with the same.

[0010] Fig. 5 is a schematic diagram of an elevator device. Fig. 6 is a front view of a hoisting machine according to an embodiment of the present invention. Fig. 7 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 8 is a view seen from the arrow IV in Fig. 3. Fig. 9 is a cross-sectional view of the coil in Fig. 4. Fig. 10 is an enlarged view of part VI in Fig. 5. Fig. 11 is an enlarged view of coil 215 in Fig. 6.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, identical elements are designated by the same reference numerals in all drawings. Furthermore, descriptions of parts having identical functions will be omitted. Note that the configurations described below are merely examples, and it is not intended that the embodiments of the present invention be limited to the specific embodiments below.

[0012] In the following embodiment, an example is shown in which the present invention is applied to a hoist of an elevator. In this embodiment, the direction along the rotation axis (main shaft) is called the "axial direction," the direction of rotation around this axial direction is called the "circumferential direction," and the direction perpendicular to the rotation axis (axial direction) is called the "radial direction."

[0013] 1 is a schematic diagram of an elevator system. A machine room 3 that houses a hoisting machine 2 is formed above a hoistway 1. A rope 4 is hung on a sheave of the hoisting machine 2, with a car 5 suspended from one end of the rope 4 and a counterweight 6 suspended from the other end of the rope 4. When the hoisting machine 2 is operated, the car 5 suspended from the rope 4 and the counterweight 6 rise and fall within the hoistway 1 so that they face each other.

[0014] Fig. 2 is a front view of a hoist according to an embodiment of the present invention, and Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.

[0015] The hoisting machine 2 includes a frame 20 that forms an outer shell, a stator 21 fixed to the frame 20, a main shaft 24 fixed to the radially inner side of the frame 20, a rotor 22 that is disposed with a gap between its radially inner side and the radially outer side of the stator 21 and has a sheave 23 fixed thereto, and a bearing 25 that is disposed between the rotor 22 and the main shaft 24. The frame 20 supports the main shaft 24 in a cantilever manner. The main shaft 24 rotatably supports the rotor 22 via the bearing 25.

[0016] The stator 21 and the rotor 22 constitute a rotating electric motor. The electric motor of this embodiment is an outer rotor type electric motor in which the rotor 22 is disposed radially outside the stator 21.

[0017] An encoder 26 that detects the rotational speed of the hoisting machine 2 is stored and fixed in a storage space 24a formed in the main shaft 24. The encoder 26 is provided with a rotating shaft (not shown) that is connected to the encoder shaft. The encoder shaft 27 is integrally formed with a large-diameter disk portion and a small-diameter cylindrical portion, and the large-diameter disk portion is attached to the rotor 22, which is the rotating portion of the electric motor, so that the encoder shaft 27 rotates in conjunction with the rotation of the rotor 22. The rotational force of the rotor 22 is transmitted to the encoder 26 via the encoder shaft 27, and the rotational speed of the rotor 22 is detected by the encoder 26.

[0018] The hoist 2 is also provided with a braking device 28 that applies a braking force to the sheave 23 .

[0019] Next, the configuration of the stator 21 will be described. Fig. 4 is a view taken along the arrow IV in Fig. 3. Fig. 5 is a cross-sectional view of the coil in Fig. 4. Note that Figs. 4 and 5 show only one tooth out of the multiple teeth.

[0020] The stator 21 includes a stator core 210 formed by stacking multiple electromagnetic steel plates, multiple teeth 212 extending from a yoke 211 of the stator core 210 toward the rotor 22 side (radially outward), slots 213 formed between adjacent teeth 212, bobbins 214 arranged to cover the teeth 212, and coils 215 wound around the teeth 212 via the bobbins 214 and arranged in the slots 213.

[0021] Fig. 6 is an enlarged view of part VI in Fig. 5. Coil 215 is formed by winding an enameled wire, which is a metal wire such as a copper wire or an aluminum wire covered with an enamel insulating film, around teeth 212. The enameled wire used for coil 215 in this embodiment is a rectangular wire 215a with a square cross section.

[0022] The flat wire 215a constituting the coil 215 is wound around the teeth 212 from the radially inner side (anti-rotor side) so as to contact the bobbin 214 made of insulating material, forming the first layer (1A-1D). The second layer (2A-2D) is then wound around the teeth 212 so as to overlap the first layer, the third layer (3A-3D) is wound around the teeth 212 so as to overlap the second layer, the fourth layer is wound around the third layer, and the fifth layer is wound around the fourth layer. That is, the flat wire 215a is wound around the teeth 212 so that the flat wires 215a are adjacent to each other in the radial direction, and is wound around the teeth 212 so that the flat wires 215a overlap each other in the circumferential direction. In this embodiment, the fourth and fifth layers are not provided on the radially inner side of the teeth 212, but are provided from the radial center of the teeth 212 toward the rotor side (radially outward).

[0023] In order to align and wind the rectangular wires 215a in the radial direction of the teeth 212, it is necessary to provide a predetermined gap between adjacent rectangular wires 215a in the radial direction. For this reason, the rectangular wires 215a are prone to shifting in the radial direction of the teeth 212.

[0024] Therefore, in this embodiment, when viewed from the circumferential direction, one flat wire 215a in the second layer (upper layer) is arranged so that it straddles and contacts two adjacent flat wires 215a in the first layer (lower layer), and one flat wire 215a in the second layer (upper layer) presses the two adjacent flat wires 215a in the first layer (lower layer) in the circumferential direction.

[0025] Of the flat wires 215a in the first layer, the flat wires 1A and 1B are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212, and the flat wires 1B and 1C are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212. Also, of the flat wires 215a in the second layer, the flat wires 2A and 2B are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212, and the flat wires 2B and 2C are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212. Similarly, of the flat wires 215a in the third layer, the flat wires 3A and 3B are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212, and the flat wires 3B and 3C are arranged side by side so as to be adjacent to each other in the radial direction of the teeth 212.

[0026] The second layer of flat wire 2A, which overlaps radially with the first layer of flat wire 215a, is arranged so as to straddle both the first layer of flat wire 1A and flat wire 1B, the second layer of flat wire 2B is arranged so as to straddle both the first layer of flat wire 1B and flat wire 1C, and the second layer of flat wire 2C is arranged so as to straddle both the first layer of flat wire 1C and flat wire 1D.

[0027] Similarly, the third layer of flat wire 3B, which overlaps the second layer of flat wire 215a in the radial direction, is arranged so as to straddle both the second layer of flat wire 2A and the second layer of flat wire 2B, the third layer of flat wire 3C is arranged so as to straddle both the second layer of flat wire 2B and the second layer of flat wire 2C, and the third layer of flat wire 3D is arranged so as to straddle both the second layer of flat wire 2C and the second layer of flat wire 2D. Although the explanation is omitted, the same applies to the fourth and fifth layers.

[0028] Vibration occurs when rotating electric machine is operated, and vibration is also transmitted to coil 215. Because the flat wires 215a adjacent to each other in the radial direction are not joined, the flat wire wound on the tooth tends to unravel due to vibration, but in this embodiment, one flat wire 215a (flat wire 2A) of upper layer (second layer) is arranged so as to straddle two flat wires 215a (flat wire 1A and flat wire 1B) of lower layer (first layer) adjacent to each other in the radial direction, so that the flat wire 215a (flat wire 1A and flat wire 1B) of lower layer (first layer) can be prevented from unraveling.

[0029] Next, a method for further enhancing the effect of preventing the coil 215 from unwinding will be described. Fig. 7 is an enlarged view of the coil 215 in Fig. 6 .

[0030] The rectangular wire 215a in this embodiment is an enameled wire, which is a metal wire such as a copper wire or an aluminum wire covered with an insulating enamel coating, as described above, but it is preferable to cover the insulating coating with a fusion layer, which is made of a thermoplastic resin such as polyamide resin or epoxy resin.

[0031] As mentioned above, in the present embodiment, the flat wire 215a is arranged with a gap between adjacent flat wires 215a in the radial direction (for example, flat wire 1A and flat wire 1B). The flat wire 2A in the second layer, which is the upper layer, is arranged across the flat wire 1A and flat wire 1B in the first layer, which is the lower layer. The flat wire 215a is provided with a fusion layer, and when heat is applied to the coil 215, the fusion layer melts and forms a joint 216 where the flat wires 215a are joined together. For example, when the fusion layers of the flat wire 1A, flat wire 1B, and flat wire 2A melt, the flat wire 1A and the flat wire 2A are joined, and the flat wire 1B and the flat wire 2A are joined. The flat wire 2A is joined to the flat wire 1A and the flat wire 1B, respectively. In other words, the flat wire 1A and the flat wire 1B are joined indirectly through the flat wire 2A. The flat wires 1A and 1B are joined to the bobbin 214 at a joint 216 formed by the melted fusion layer. That is, the flat wires 1A and 1B are joined indirectly via the bobbin 214.

[0032] Similarly, the flat wire 2A and the flat wire 2B are indirectly joined via the flat wire 1B and the flat wire 3B.

[0033] According to this embodiment, the radially adjacent flat wires 215a arranged in each layer are indirectly joined to the flat wires 215a of other circumferentially adjacent layers or via the bobbin 214, thereby further enhancing the effect of preventing the coil 215 from unraveling.

[0034] In this embodiment, a bobbin 214 is disposed between the teeth 212 and the rectangular wire 215a, and as shown in Fig. 6, a stepped portion 214a is provided at the radially outer end of the bobbin 214. The stepped portion 214a is formed integrally with the bobbin 214. The rectangular wire 215a (e.g., rectangular wire 2D) located at the radially outer end is disposed so as to fit within the stepped portion 214a.

[0035] In this embodiment, in order to arrange one flat wire 215a of the second layer (upper layer) so that it straddles and contacts two adjacent flat wires 215a of the first layer (lower layer), the depth W1, which is the radial dimension of the step 214a, is set to be smaller than the width W2, which is the radial dimension of the flat wire 215a (W1<W2).The depth W1 can be set appropriately so that one flat wire 215a of the upper layer straddles two adjacent flat wires 215a of the lower layer.

[0036] In addition, if the flat wire 215a (for example, the flat wire 2D) located at the radially outer end runs onto the step portion 214a, the effect of the upper layer pressing down on the two adjacent lower layers will be weakened, and there is a possibility that the coil 215 will be unraveled. In particular, if a fusion layer is provided on the flat wire 215a, there is a possibility that the flat wire 215a (for example, the flat wire 2D) located at the radially outer end will not be joined to the flat wire 1D and the flat wire 3D.

[0037] Therefore, in this embodiment, the height H1, which is the circumferential dimension of the step portion 214a, is set to be lower than the height H2, which is the circumferential dimension of the rectangular wire 215a (H1 < H2). In other words, the height H2 of the rectangular wire 215a is set to be higher than the height H1 of the step portion 214a. However, if the height H2 of the rectangular wire 215a is too high compared to the height H1 of the step portion 214a (if the difference between H1 and H2 becomes too large), the effect of the upper layer holding down the two adjacent lower layers will be weakened, and the coil 215 may unravel. Therefore, in this embodiment, the height H2 of the rectangular wire 215a is set to be within +0.1 to 1% of the height H1 of the step portion 214a. By configuring in this way, the coil 215 can be prevented from unraveling.

[0038] In this embodiment, the step portion 214 a is formed integrally with the bobbin 214 , but it may be formed separately from the bobbin 214 .

[0039] Furthermore, although the present embodiment has been described as being applied to an outer rotor type electric motor, it may also be applied to an inner rotor type electric motor.

[0040] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0041] 21... stator, 22... rotor, 23... sheave, 210... stator core, 211... yoke, 212... teeth, 213... slot, 214... bobbin, 214a... step portion, 215... coil, 215a... rectangular wire, 216... joint portion, 1A to 1D, 2A to 2D, 3A to 3D... rectangular wire

Claims

1. A rotating electric machine comprising a stator and a rotor arranged with a gap between them, wherein the stator comprises a stator core, a plurality of teeth extending from a yoke of the stator core towards the rotor, and coils wound around the teeth via bobbins, wherein the coils are composed of a lower layer in which rectangular wire with a square cross section is wound radially so as to contact the bobbin, and an upper layer in which rectangular wire is wound radially so as to overlap the lower layer, and one rectangular wire of the upper layer is arranged so as to straddle two adjacent rectangular wires of the lower layer.

2. A rotating electric machine according to claim 1, characterized in that a stepped portion is provided at the radially outer end of the bobbin.

3. A rotating electric machine according to claim 2, characterized in that the depth, which is the radial dimension of the step portion, is made smaller than the width, which is the radial dimension of the rectangular wire.

4. A rotating electric machine according to claim 2, characterized in that the height of the stepped portion in the circumferential direction is made smaller than the height of the rectangular wire in the circumferential direction.

5. A rotating electric machine according to claim 1, characterized in that the rectangular wire is covered with a fusion layer.

6. A rotating electric machine according to claim 2, wherein the step portion is formed as a separate body from the bobbin.

7. A hoist comprising a rotating electric machine having a stator and a rotor, and a sheave fixed to the rotor, wherein the rotating electric machine is any one of the rotating electric machines of claims 1 to 6.

Images