JP2006296033A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor having a high winding factor in which cogging is reduced while employing a combination of P and S capable of parallel connection. <P>SOLUTION: A stator core 11 is provided with a plurality of salient poles 14a being applied with a coil 12, and slots 15 formed between the salient poles 14a. The slot 15 is provided with a salient pole 14b not applied with a coil. A relation of 10:6 is set between the number of poles of permanent magnets of a rotor 3 and the number of slots 15 of a stator 4. The salient poles 14b project from the yoke portion 13 of the stator core 11 and a dovetail groove being fitted with the dovetail portion of a split core 11b forming the salient pole 14a is provided between the salient poles 14b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brushless motor, and more particularly to a stator structure of a brushless motor.

  In recent years, in various operating machines such as industrial robots, the use of brushless motors excellent in maintainability and controllability is expanding. As such brushless motors, those having a rotor pole number P and a status lot number S of 8 poles and 9 slots (hereinafter abbreviated as 8P9S) are often used. However, in the 8P9S motor, as shown in FIG. 6, the phase of the coil 52 facing the magnet 51 is shifted by 20 ° in electrical angle. For this reason, as shown in FIG. 7, a phase difference arises in the induced voltage of each coil in each phase.

If the induced voltage of each coil has a phase difference, connecting in-phase coils 52 (for example, U1, U2, U3) in parallel as shown in FIG. 8 will cause circulating current in the parallel circuit and inhibit motor torque generation. To do. Therefore, in the 8P9S brushless motor, it is common to form a winding by connecting in-phase coils 52 in series as shown in FIG.
Japanese Unexamined Patent Publication No. 2000-253602

  However, when in-phase coils are connected in series as shown in FIG. 9, the coil wire diameter must be increased (for example, the wire diameter is 1.2 mm), and the coil space factor deteriorates and the copper loss increases. is there. On the other hand, if a combination of 8P12S, for example, is selected as the relationship between P and S in order to form a brushless motor with priority on parallel connection and no coil phase difference, the winding coefficient is reduced and the generated torque is reduced. . Further, when 10P6S or 14P6S is adopted as a combination that can be connected in parallel, as shown in FIG. 10, the magnetic flux concentrates on the yoke portion 54 of the stator 53 (X portion), the saliency increases, and the cogging increases.

  An object of the present invention is to provide a brushless motor having a high winding coefficient and a small cogging, while being a combination of P and S capable of parallel connection.

  A brushless motor according to the present invention includes a stator having a plurality of salient poles around which coils are wound and a core member having slots formed between the salient poles, and a stator that is rotatably disposed on the inner peripheral side of the stator. A brushless motor having a rotor attached along a circumferential direction so that a plurality of permanent magnets are opposed to the salient poles, wherein the coil is not wound in each slot. A pole is provided.

  In the present invention, the magnetic path of the magnetic flux formed by the coil is dispersed by disposing the auxiliary salient pole not wound with the coil between the salient poles wound with the coil. For this reason, magnetic flux saturation is less likely to occur at the yoke portion of the core member, and accordingly, the yoke portion can be made thinner, and the motor outer diameter can be reduced.

  In the brushless motor, the relationship between the number of poles of the permanent magnet and the number of slots may be set to 10: 6 or 14: 6. Although the 10P6S and 14P6S configurations can be connected in parallel, the winding coefficient is small and the generated torque is reduced. However, the auxiliary salient poles make these motors substantially 10P12S and 14P12S configurations, so they can be connected in parallel. However, the winding coefficient can be improved. Therefore, it is possible to improve both the parallel connection and the winding coefficient, increase the coil space factor, reduce the copper loss, and improve the output torque.

  In the brushless motor, the core member includes a yoke portion formed in an annular shape, the auxiliary salient pole formed to project from the yoke portion along a radial direction, and the auxiliary projection adjacent to the yoke portion. It is good also as a structure which has a main body core provided with the dovetail groove | channel formed between the poles, and a division | segmentation core which comprises the dove part fitted to the dovetail groove and forms the said salient pole. Thus, the coil space factor is further improved by providing the salient poles for winding the coil separately from the main body core. In this case, a coil unit formed by winding a conducting wire in a ring shape may be attached to the divided core, thereby improving the assembling workability of the motor.

  In the brushless motor, a set bolt hole through which a set bolt for motor assembly is inserted may be provided in the auxiliary salient pole base portion of the core member. By providing the set bolt hole at the base portion of the auxiliary salient pole, the set bolt can be disposed inside the yoke portion, and the motor outer diameter can be reduced. In this case, the brushless motor is provided with a housing in which the stator is accommodated and an end case attached to the end of the housing, and a set bolt hole is opposed to a portion of the end case facing the auxiliary salient pole. Bolt insertion holes may be formed.

  Further, in the brushless motor, the brushless motor is provided with a housing in which the stator is accommodated and an end case attached to an end of the housing, and the motor is provided at a portion facing the auxiliary salient pole of the end case. A female screw hole for attachment may be provided. Thereby, the axial length of the motor can be reduced, and the motor can be miniaturized. Also, even if a bolt longer than the specified length is used by mistake for the mounting bolt, the female screw hole is provided in a place unrelated to the coil, so the coil is not damaged and assembled. Workability and product reliability are improved.

  According to the brushless motor of the present invention, a stator having a plurality of salient poles around which coils are wound and having a core member in which slots are formed between the salient poles, and a stator that is rotatably arranged on the inner peripheral side of the stator. The auxiliary salient pole that does not wind the coil is provided in each slot of the brushless motor that is provided and has a rotor attached along the circumferential direction so that a plurality of permanent magnets are opposed to the salient pole. The magnetic path of the magnetic flux to be formed is dispersed, so that the magnetic flux is less likely to be saturated in the core member, so that the core member can be miniaturized and the motor outer diameter can be reduced.

  In addition, according to the brushless motor of the present invention, by setting the relationship between the number of poles of the permanent magnet and the number of slots to 10: 6 or 14: 6, a 10P6S or 14P6S configuration having a small winding coefficient that can be connected in parallel. These motors can be substantially configured as 10P12S or 14P12S by auxiliary salient poles. As a result, it is possible to achieve both the parallel connection and the improvement of the winding coefficient, increase the coil space factor, reduce the copper loss, and improve the output torque.

  Further, according to the brushless motor of the present invention, the core member is formed between the annular yoke portion, the auxiliary salient pole protruding from the yoke portion, and the auxiliary salient pole adjacent to the yoke portion. By having a structure having a main body core provided with a groove and a split core forming a salient pole with a dove part that fits into the dovetail groove, by providing a salient pole for applying a winding separately from the main body core Further, the coil space factor is further improved. In addition, assembling workability of the motor is improved by attaching a coil unit formed by winding a conducting wire to the split core.

  On the other hand, according to the brushless motor of the present invention, by providing a set bolt hole through which a set bolt for motor assembly is inserted in the auxiliary salient pole base of the core member, the set bolt can be disposed more inside the core member, The motor outer diameter can be further reduced.

  According to the brushless motor of the present invention, the brushless motor is provided with a housing and an end case, and the end case is provided with a female screw hole for mounting the motor at a portion facing the auxiliary salient pole, thereby increasing the axial length of the motor. Therefore, the motor can be downsized. In this case, even if a bolt longer than the predetermined length is used by mistake for the mounting bolt, the female screw hole is provided in a place unrelated to the coil, so that the coil is not damaged. It is possible to improve workability and product reliability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a configuration of a brushless motor 1 (hereinafter abbreviated as a motor 1) according to an embodiment of the present invention, where (a) is a front view thereof and (b) is an A- It is sectional drawing along the A line. FIG. 2 is an explanatory diagram showing a cross-sectional configuration of the brushless motor of FIG.

  As shown in FIGS. 1 and 2, the motor 1 has an inner rotor type device configuration in which a stator 4 is disposed outside a rotor 3 having a magnet 2. The rotor 3 includes a rotor core 6 attached to a metal shaft 5 and a magnet 2 fixed to the outer periphery of the rotor core 6. The magnet 2 is made of a permanent magnet and has a 10-pole configuration divided into 10 segments. The shaft 5 is rotatably supported by a bearing 8 attached to the end case 7. The end case 7 is fixed to the left end portion of the housing 9 in FIG. A hall sensor (not shown) for detecting the rotational position of the rotor 3 is disposed on the right end side of the housing 9 in the drawing.

  The stator 4 includes a stator core 11 (core member) formed by laminating annular steel plates and fixed to the inner peripheral side of the housing 9, and a coil 12 wound around the stator core 11. The stator core 11 is provided with a yoke portion 13 formed in an annular shape and a salient pole 14 projecting radially inward from the yoke portion 13. Twelve salient poles 14 are formed on the yoke portion 13 at regular intervals (30-degree pitch) along the circumferential direction. Slots 15 are formed between adjacent salient poles 14.

  A coil 12 is wound around the salient pole 14. The coil 12 is connected to a drive circuit (not shown). As shown in FIG. 2, the salient pole 14 includes a salient pole 14 a around which the coil 12 is wound and a salient pole 14 b (auxiliary salient pole) around which the coil 12 is not wound. The salient poles 14a and 14b are alternately arranged, and the motor 1 has a 10P12S configuration in appearance. That is, the motor 1 has a configuration in which salient poles that are not wound are added by the number of slots between slots of a 10P6S motor as shown in FIG.

  FIG. 3 is an explanatory diagram showing the configuration of the salient poles 14a and 14b. As shown in FIG. 3, the salient pole 14 b is formed integrally with the yoke portion 13, and the salient pole 14 a is formed separately from the yoke portion 13 and attached to the yoke portion 13 later. That is, the stator core 11 is composed of a main body core 11a in which the salient poles 14b project in the inner circumferential direction, and a split core 11b that forms the salient poles 14a. By attaching to 11a, the stator core 11 provided with the 12 salient poles 14 is formed.

  As shown in FIG. 3, a groove 16 is formed on the inner peripheral surface of the yoke portion 13 along the axial direction (steel plate stacking direction). The dovetail groove 16 is provided at an intermediate position between the salient poles 14 b and opens into the slot 15. A dovetail portion 17 corresponding to the dovetail groove 16 protrudes from the outer peripheral side end of the split core 11b. The dovetail part 17 is formed in the dovetail groove 16 so as to be fitted. The split core 11 b is attached from the end side of the main body core 11 a, and at this time, the dovetail portion 17 is press-fitted into the dovetail groove 16. Thereby, the split core 11b is fixed to the main body core 11a.

  When the divided core 11b is fixed to the main body core 11a, the coil 12 is attached to each divided core 11b as shown in FIG. The coil 12 is a coil unit 18 in which a conducting wire is wound in advance and is formed in a ring shape, and a core mounting hole 18a is provided at the center thereof. By inserting the split core 11b through the core mounting hole 18a and fixing the split core 11b to the main body core 11a in this state, the stator 4 as shown in FIG. 2 is formed. Thus, the coil space factor can be improved by providing the salient pole which winds in another body, attaching the coil unit 18 to this, and forming the coil 12. FIG.

  Coil 12 is formed as a pair of two facing each other to form a three-phase winding of U, V, and W (+ U1, -U; + V, -V; + W, -W). . The coil 12 forms a magnetic flux flow as shown in FIG. As is clear from comparison of FIG. 2 with FIG. 10, in the configuration of FIG. 2, the magnetic flux is not evenly concentrated on a part of the yoke portion 13, and is evenly arranged through the salient poles 14. That is, the magnetic path of the magnetic flux formed by the coil 12 is dispersed by the presence of the so-called dummy pole (the salient pole 14b) around which the coil 12 is not wound. Therefore, the magnetic flux saturation of the yoke portion 13 is less likely to occur, and accordingly, the yoke portion 13 can be made thinner and the motor outer diameter can be reduced. Further, the salient poles 14b make the motor 1 substantially have a 10P12S configuration, so that multiple poles and saliency are reduced and cogging is reduced.

  Here, in the 10P6S configuration, parallel connection is possible, but if not, the winding coefficient is small and the generated torque is reduced. On the other hand, in the 8P9S configuration, the winding coefficient can be increased, but parallel connection cannot be performed, the coil space factor becomes worse, and the copper loss increases. On the other hand, since the basic configuration of the motor 1 is 10P6S, there is no phase difference in the in-phase coil, and the in-phase coil can be connected in parallel. In addition, since the number of salient poles around which no coil is wound is provided as many as the number of slots, the 10P6S motor has a substantially 10P12S configuration, so that the winding coefficient can be improved while parallel connection is possible.

  Therefore, as compared with the 8P9S motor, parallel connection is possible while maintaining the winding coefficient, and the coil space factor can be increased to reduce the copper loss. FIG. 4 is a graph showing the torque / copper loss ratio (motor constant Km) of various motors according to experiments by the inventors. As shown in FIG. 4, the motor 1 has a larger Km than an 8P9S motor or an 8P12S motor that can be connected in parallel. In particular, it was found that the torque was improved by 21% for the current 8P9S motor.

  On the other hand, the end case 7 is provided with a bolt mounting portion 21 for attaching the set bolt 10 and a female screw hole 23 for fixing the motor 1 to the bracket 22 in the form shown in FIG. The bolt mounting portion 21 and the female screw hole 23 are formed at three equal intervals along the circumferential direction. Further, as shown in FIGS. 1B and 3, a set bolt hole 24 through which the set bolt 10 is inserted is provided at the base portion of the salient pole 14 b corresponding to the bolt mounting portion 21.

  Here, in the conventional brushless motor, since the coil is wound around all the salient poles, the bolt holes for the set bolts must be provided in the yoke portion of the stator core. For this reason, there is a problem that the outer diameter of the motor increases correspondingly, which hinders miniaturization of the motor. Also, when fixing the motor to a bracket, etc., in order to avoid the coil, the bolt for fixing the end case is arranged on the outer diameter side of the coil, or the end case is made thicker in the axial direction by the length of the bolt. This also hinders miniaturization of the motor. Furthermore, in this case, when a motor having a predetermined length or longer is mistakenly used when attaching the motor, the coil may be damaged by the bolt.

  On the other hand, in the motor 1, since the coil 12 is not wound around the salient pole 14b, the set bolt hole 24 can be provided at the base of the salient pole 14b. As shown in FIG. 1, the coil 12 is arranged at the left end of the salient pole 14a in the drawing, but the coil 12 does not exist at the left end of the salient pole 14b. Therefore, in the motor 1, in order to effectively use the space where the coil 12 does not exist, the set bolt hole 24 is arranged at the base portion of the salient pole 14 b and the bolt mounting portion 21 is formed inside the yoke portion 13.

  As shown in FIG. 1A, the bolt mounting portion 21 is formed with a convex portion 25 in which the inner bottom surface 7a of the end case 7 protrudes to the right side in FIG. When the end case 7 is attached to the housing 9, a bolt insertion hole 26 that is disposed to face the set bolt hole 24 is formed in the convex portion 25. On the outer side of the end case 7, a bolt insertion hole 26 is opened, and a cutout portion 27 in which the head of the set bolt 10 is accommodated is provided.

  While three bolt mounting portions 21 are provided, female screw holes 23 are provided in the remaining three portions of the space corresponding to the salient poles 14b as shown in FIG. A convex portion 28 is formed on the inner bottom surface 7 a of the end case 7 in the same manner as the bolt mounting portion 21. That is, six convex portions 25 and 28 are alternately provided on the inner bottom surface 7a of the end case 7 at intervals of 120 °, and each convex portion 25 and 28 faces the axial end of the salient pole 14b. It is arranged with. A female screw hole 23 is formed in the convex portion 28, and a mounting bolt 29 for fixing the end case 7 to the bracket 22 is screwed into the female screw hole 23.

  Thus, in the motor 1, the bolt mounting portion 21 and the female screw hole 23 are provided using the space created by the salient pole 14 b around which the coil 12 is not wound, so that the outer diameter and axial length of the motor are increased. Without this, the set bolt 10 and the mounting bolt 29 can be arranged. For this reason, the outer diameter and axial length of the motor can be reduced, and the motor can be reduced in size.

  Even if the mounting bolt 29 having a predetermined length or longer is used by mistake, the female screw hole 23 is provided in a place unrelated to the coil 12, so that the coil is not damaged. Improves workability and product reliability. In consideration of the case where the mounting bolt 29 having a predetermined length or more is used, a relief hole may be provided in the base portion of the salient pole 14 b corresponding to the female screw hole 23. If the escape hole and the set bolt hole 24 are used in common, the positional direction between the end case 7 and the stator core 11 is eliminated, so that the assembly workability is improved.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the salient pole 14b is formed integrally with the yoke portion 13 and the salient pole 14a is formed separately from the yoke portion 13, but conversely, the salient pole 14a is formed. May be formed integrally with the yoke portion 13, and the salient pole 14 b may be formed separately from the yoke portion 13. In this case, the salient pole 14b is attached after the coil 12 is wound around the salient pole 14a. The salient poles 14a and 14b are not necessarily configured to be detachable.

  In addition, combinations of P and S are possible other than 10P6S. From various combinations, a) parallel connection is possible, b) winding factor is high, c) improvement in cost, workability, and motor performance can be expected. It can be selected as appropriate in consideration of such conditions. As a combination that satisfies these conditions, for example, a combination such as 14P6S is also effective as an object of the present invention. Furthermore, in the above-described embodiments, an example in which the present invention is applied to an inner rotor type motor has been described. However, the present invention can also be applied to an outer rotor type motor in which a rotor is disposed outside a stator core.

It is explanatory drawing which shows the structure of the brushless motor which is one Example of this invention, (a) is the front view, (b) is sectional drawing along the AA of (a). It is explanatory drawing which shows the cross-sectional structure of the brushless motor of FIG. It is explanatory drawing which shows the structure of a salient pole. It is a graph which shows the ratio (motor constant Km) of the torque / copper loss of various motors by experiment of inventors. It is explanatory drawing which shows a mode that the motor was fixed to the bracket, and a motor part is corresponded in the BB cross section of FIG. It is explanatory drawing which shows the structure of a brushless motor of 8 poles and 9 slots. It is explanatory drawing which shows the induced voltage of the U phase in an 8-pole 9-slot brushless motor. It is explanatory drawing which shows the state which connected the coil of the same phase in parallel with the brushless motor of 8 poles and 9 slots. It is explanatory drawing which shows the state which connected the coil of the same phase in series with the brushless motor of 8 poles and 9 slots. It is explanatory drawing which shows the flow of the magnetic flux in a 10 pole 6 slot brushless motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Magnet 3 Rotor 4 Stator 5 Shaft 6 Rotor core 7 End case 7a Inner bottom face 8 Bearing 9 Housing 10 Set bolt 11 Stator core (core member)
11a main body core 11b split core 12 coil 13 yoke 14 salient pole 14a salient pole 14b salient pole (auxiliary salient pole)
15 slot 16 dovetail groove 17 dovetail part 18 coil unit 18a core attachment hole 21 bolt attachment part 22 bracket 23 female screw hole 24 set bolt hole 25 convex part 26 bolt insertion hole 27 notch part 28 convex part 29 mounting bolt 51 magnet 52 coil P rotor Number of magnetic poles S Number of status lots

Claims (7)

A stator having a core member having a plurality of salient poles around which a coil is wound and having a slot formed between the salient poles; and a plurality of permanent magnets rotatably disposed on the inner peripheral side of the stator. A brushless motor having a rotor attached along the circumferential direction so as to face the salient poles,
A brushless motor, wherein an auxiliary salient pole that does not wind the coil is provided in each slot.   2. The brushless motor according to claim 1, wherein the relationship between the number of poles of the permanent magnet and the number of slots is 10: 6 or 14: 6.   3. The brushless motor according to claim 1, wherein the core member includes a ring-shaped yoke portion, the auxiliary salient pole formed in a radial direction projecting from the yoke portion, and the yoke portion. A main core including a dovetail groove formed between adjacent auxiliary salient poles, and a split core including a dovetail portion that fits into the dovetail groove and forming the salient poles. Brushless motor.   The brushless motor according to any one of claims 1 to 3, wherein the divided core is mounted with a coil unit formed by winding a conducting wire in a ring shape.   The brushless motor according to any one of claims 1 to 4, wherein a set bolt hole through which a set bolt for motor assembly is inserted is provided in the auxiliary salient pole base of the core member. motor.   6. The brushless motor according to claim 5, wherein the brushless motor includes a housing in which the stator is accommodated, and an end case attached to an end portion of the housing, and the end case is opposed to the auxiliary salient pole. A brushless motor having a bolt insertion hole facing the set bolt hole. The brushless motor according to any one of claims 1 to 5, wherein the brushless motor includes a housing in which the stator is accommodated, and an end case attached to an end portion of the housing. A brushless motor having a female screw hole for mounting the motor at a portion facing the auxiliary salient pole.

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