JP2008312348A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor capable of reducing the frequency of maintenance of a metal mold used for stamping and reducing the manufacturing cost, and an electric motor capable of improving the lamination strength of split cores of a stator and enhancing the accuracy of manufacture of the split cores. <P>SOLUTION: The electric motor is provided with an annular stator and a rotor provided freely rotatably for the stator. The stator core 10 of the stator is constituted of a plurality of split cores 30 split along the circumferential direction, and the split cores 30 are formed by laminating a plurality of metal plates 29 so as to skew, while being twisted in the laminating direction, and a coil is wound around teeth 33, formed on each of the split cores 30 and extending in the radial direction. An adhesive groove 50 is formed over the entire laminating direction of each of the split cores 30 and an adhesive 51 is applied to the adhesive groove 50. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric motor including a divided core obtained by dividing a stator core of a stator.

  Generally, an electric motor includes a stator formed in an annular shape and a rotor provided to be rotatable with respect to the stator. Teeth extending in the radial direction are formed on the stator, and a coil is wound around the teeth. On the other hand, a permanent magnet is disposed on the rotor so as to face the tip of the teeth. The rotor is rotated by controlling energization of the coil.

By the way, in order to make it easy to wind a coil around a tooth, there is a stator in which a divided core including a tooth is divided in the circumferential direction along an axis. Thus, in the split core type stator, since the stator can be assembled after winding the coil for each split core, the space factor of the coil can be increased.
Moreover, in order to suppress the vibration resulting from rotation nonuniformity in some split cores, there are those in which teeth are inclined (skew). As such a stator, there is used a laminate in which electromagnetic steel sheets punched by press working are gradually shifted in the circumferential direction. By doing in this way, the teeth which incline with respect to an axial direction can be manufactured integrally (for example, refer to patent documents 1).
JP 2006-33989 A

However, in the above-described prior art, when laminating the electromagnetic steel sheets, each electromagnetic steel sheet is formed with a boss portion, and this boss portion is laminated while being squeezed to bond the electromagnetic steel sheets, respectively, There are cases where the magnetic steel sheets are applied to the mating surfaces of the magnetic steel sheets and bonded to each other.
In particular, when each magnetic steel sheet is bonded using an adhesive, the magnetic steel sheet coated with the adhesive is punched out by pressing, so that the adhesive adheres to the press mold and the mold is cut. There is a problem that the mold may be damaged and the maintenance frequency of the mold is increased.

Moreover, in order to adhere | attach each electromagnetic steel plate, it is necessary to heat while heating an electromagnetic steel plate, and there exists a subject that expense, such as preparing a pressurization jig and an electric furnace, increases.
Furthermore, it is difficult for the adhesive to be evenly applied to the mating surfaces of the magnetic steel sheets, and a portion having a low adhesive strength is formed. For this reason, in the split core laminated | stacked in skew, there exists a subject that stress may generate | occur | produce locally when a coil is wound around a tooth | gear, and there exists a possibility that a split core may become scattered.
Then, there is a problem that the adhesive protrudes to the outside beyond a specified value, and the manufacturing accuracy of the split core is lowered.

Therefore, the present invention has been made in view of the above-described circumstances, and provides an electric motor capable of reducing the maintenance frequency of a mold used for press working and reducing the manufacturing cost.
It is another object of the present invention to provide an electric motor that can increase the lamination strength of the split cores of the stator and can improve the manufacturing accuracy of the split cores.

  In order to solve the above-described problems, the invention described in claim 1 includes an annular stator and a rotor that is rotatably provided with respect to the stator, and the stator core of the stator extends along the circumferential direction. The divided core is composed of a plurality of divided cores, and the divided core is formed by laminating a plurality of metal plates and skewing while twisting in the stacking direction, and is formed in each divided core along the radial direction. An electric motor in which a coil is wound around an extending tooth, wherein an adhesive groove is formed in each of the divided cores in the entire lamination direction, and an adhesive is applied to the adhesive groove.

  The invention described in claim 2 is characterized in that the adhesive grooves are formed on an inner peripheral side and an outer peripheral side of the divided core.

  The invention described in claim 3 is characterized in that the adhesive grooves are skewed.

According to the present invention, since the adhesive groove for applying the adhesive is formed on each divided core, the adhesive can be applied after the metal plates are laminated. For this reason, when the metal plate is punched out by press working, it is not necessary to use a metal plate coated with an adhesive, and the maintenance frequency of the mold can be reduced.
Further, since it is not necessary to bond the metal plates when laminating the metal plates, a pressing jig and an electric furnace become unnecessary. For this reason, it becomes possible to reduce the manufacturing cost of a split core.

Furthermore, since the adhesive grooves are formed over the entire stacking direction, the bonding strength between the metal plates can be increased. In this case, by forming the adhesive grooves on the inner peripheral side and the outer peripheral side of the split core, the location where the adhesive is applied is not biased to one location. That is, the location where the adhesive is applied is not biased to either the inner peripheral side or the outer peripheral side, and the adhesive strength can be further increased.
And by apply | coating an adhesive agent to an adhesion groove | channel, the adhesive agent does not protrude beyond a regulation value from a division | segmentation core, and the manufacture precision of a division | segmentation core can be improved.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the electric motor 1 is a brushless type electric motor having a stator 3 press-fitted into a housing 2 and a rotor 4 provided rotatably with respect to the stator 3. It is used for power steering (EPS).

  The housing 2 has a bottomed cylindrical shape, and the stator 3 is press-fitted into the inner periphery of the cylindrical portion. The end portion (bottom portion) 2A of the housing 2 is press-fitted with a bearing 5 at the center. A rotating shaft 6 of the rotor 4 is rotatably supported on the bearing 5. The opening of the housing 2 is closed with a bracket 7.

The stator 3 has a substantially cylindrical stator core 10, and a coil 12 is wound after an insulator 11, which is an insulating member, is mounted on the stator core 10.
In the rotor 4, a permanent magnet 13 and a resolver rotor 14 </ b> A of a position detection resolver 14 are arranged in order on the rotating shaft 6. The permanent magnet 13 is magnetized so that the magnetic poles change in order in the circumferential direction.

  The bracket 7 has a disk shape, and a hole 20 is formed at the center. A bearing 21 is press-fitted and fixed in the hole 20, and the rotating shaft 6 is rotatably supported by the bearing 21. Further, a resolver stator 14B constituting the resolver 14 is fixed in accordance with the position of the resolver rotor 14A, and the rotational position of the resolver rotor 14A that rotates integrally with the rotary shaft 6 can be detected.

  A plurality of terminals 22 are arranged on the housing 2 side of the bracket 7. The terminal 22 has a role of electrically connecting the terminal portion of the coil 12 on the stator 3 side and the lead wire 23 drawn from the outer periphery of the bracket 7, and from an external power source connected via the lead wire 23. A current can be supplied to the coil 12. In addition, a bolt hole 24 that is used when the electric motor 1 is fixed projects from the outer peripheral portion of the bracket 7.

  Here, as shown in FIGS. 2 to 4, the stator core 10 uses a split core system that can be split in the circumferential direction. The divided core 30 divided from the stator core 10 is obtained by laminating a plurality of metal plates 29 punched by pressing or the like in the axial direction, and has a core body 31 extending in the circumferential direction. For example, an electromagnetic steel plate is used for the metal plate 29.

  The core body 31 constitutes the outer peripheral portion of the stator core 10 and is a portion that forms an annular magnetic path and is a portion that fits into the inner peripheral surface of the housing 2. The core body 31 is formed in a substantially arc shape in plan view, and has a predetermined skew angle a so as to be inclined (skew) while being twisted with respect to the longitudinal direction (axial direction, stacking direction) of the stator core 10. .

  Both end portions in the circumferential direction of the core body 31 are connection portions 32A and 32B that are connected to the other divided cores 30 by press-fitting. One connecting portion 32A has a convex shape, and the other connecting portion 32B has a concave shape capable of receiving the connecting portion 32A. Thereby, it is possible to connect the divided cores 30 to form the substantially cylindrical stator core 10.

Further, on the outer peripheral side of each core body 31, an adhesive groove 50 for applying the adhesive 51 over the entire axial direction is formed at a substantially central portion in the circumferential direction. The adhesive groove 50 is formed in a substantially U-shaped cross section and is skewed in the same manner as the core body 31.
On the inner peripheral side of the core body 31, teeth 33 that are salient poles are integrally extended from the substantially center in the circumferential direction toward the center of rotation in the radial direction. An insulator 11 is attached to the teeth 33, and the coil 12 is wound through the insulator 11. The teeth 33 are also skewed similarly to the core body 31.

  An end portion on the inner peripheral side of the teeth 33 is an inner peripheral portion 34 that extends in the circumferential direction and forms the inner periphery of the split core 30. On the inner peripheral surface of the inner peripheral portion 34, two adhesive grooves 35 and 35 for applying the adhesive 51 are formed over the entire axial direction. These adhesive grooves 35, 35 are formed at the same skew angle as the teeth 33, and the teeth 33 are in a state where three teeth are formed for one divided core 30 by the two adhesive grooves 35, 35. ing.

Next, the manufacturing procedure of the split core 30 will be described.
First, the metal plate 29 punched by press working or the like is laminated in the axial direction. At this time, in order to skew the divided cores 30, the metal plates 29 are stacked while being gradually shifted in the circumferential direction. In order to temporarily maintain the laminated state of the metal plates 29, each metal plate 29 may be subjected to boss processing, and the metal plates 29 may be stacked while caulking these bosses. As described above, the metal plates 29 may be laminated together using a small amount of adhesive. Further, the caulking work for forming these bosses and the adhering work using an adhesive may be performed together.

  Next, an axis is formed between the adhesive groove 50 formed on the outer peripheral side of the core body 31 of the split core 30 and the two adhesive grooves 35 and 35 formed on the inner peripheral portion 34 of the inner peripheral side end of the teeth 33. The adhesive 51 is applied over the entire direction (see FIG. 2). At this time, an operation is performed so that the thickness of the applied adhesive 51 does not become thicker than the depth of each of the adhesive grooves 50 and 35. Thereby, the production of the split core 30 is completed.

  Therefore, according to the above-described embodiment, since the adhesive grooves 35 and 50 for applying the adhesive 51 to the split cores 30 are formed, for example, when the metal plate 29 is laminated using the adhesive 51 Even so, the adhesive 51 can be applied to the split core 30 after the lamination without using the adhesive 51 almost at the time of lamination. For this reason, when the metal plate 29 is punched by press working, it is possible to prevent the adhesive 51 from adhering to the press mold, and the maintenance frequency of the mold can be reduced.

  Further, since the metal plates 29 are bonded by the adhesive 51 after the metal plates 29 are stacked, it is not necessary to bond the metal plates 29 firmly to each other at the time of stacking. For this reason, when laminating | stacking the metal plate 29, it is not necessary to heat while pressing, and a pressurizing jig and an electric furnace become unnecessary. Therefore, the manufacturing cost of the split core 30 can be reduced.

  Furthermore, since the bonding grooves 35 and 50 are formed over the entire axial direction, the bonding strength between the metal plates 29 can be increased. Moreover, since the adhesive groove 50 is formed in the core body 31 that is the outer peripheral side of the split core 30 and the adhesive groove 35 is formed in the inner peripheral portion 34 that is the inner peripheral side of the split core 30, The location where the adhesive 51 is applied is not biased to either the inner peripheral side or the outer peripheral side. For this reason, it becomes possible to raise adhesive strength more. Therefore, when the coil 12 is wound around the divided cores 30 stacked with skew, it is possible to prevent the divided cores 30 from being separated even if stress is locally generated in the divided cores 30.

Since the adhesive 51 is applied to each of the adhesive grooves 35 and 50, it is possible to work so that the thickness of the applied adhesive 51 does not become thicker than the groove depth of each of the adhesive grooves 50 and 35. The adhesive 51 does not protrude beyond the specified value. For this reason, the manufacturing precision of a split core can be improved.
The prescribed value of the amount of adhesive 51 protruding to the outside of the split core 30 is based on the allowance for press-fitting into the housing 2 on the core body 31 side, and on the inner peripheral portion 34 side. It is desirable to set based on the air gap with 4.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
Further, in the above-described embodiment, the case where the electric motor 1 is a brushless type electric motor having the stator 3 press-fitted into the housing 2 and the rotor 4 provided to be rotatable with respect to the stator 3 has been described. However, the present invention is not limited to this, and a brushed type electric motor may be used as long as the stator 3 is formed of a split core that can be divided in the circumferential direction.

  And in the above-mentioned embodiment, the case where both the adhesion groove 50 formed in the core main body 31 of the split core 30 and the adhesion groove 35 formed in the inner peripheral part 34 are skewed similarly to the core main body 31 is demonstrated. However, the present invention is not limited to this, and it is only necessary that the adhesive grooves 35 and 50 be formed along the axial direction, that is, the stacking direction of the metal plates 29 without being skewed.

It is a longitudinal section showing the composition of the electric motor in the embodiment of the present invention. It is a perspective view of the stator core in the embodiment of the present invention. It is a perspective view of the split core in embodiment of invention. It is a perspective view of the split core in embodiment of invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 3 Stator 4 Rotor 12 Coil 29 Metal plate 30 Divided core 31 Core main body 33 Teeth 34 Inner peripheral parts 35 and 50 Adhesive groove 51 Adhesive

Claims (3)

An annular stator;
A rotor provided rotatably with respect to the stator,
The stator core of the stator is composed of a plurality of divided cores divided along the circumferential direction,
The split core is formed by laminating a plurality of metal plates and skewing while twisting in the stacking direction,
An electric motor in which a coil is wound around teeth formed in each divided core and extending along the radial direction,
An electric motor characterized in that an adhesive groove is formed in each of the split cores in the entire lamination direction, and an adhesive is applied to the adhesive groove.   The electric motor according to claim 1, wherein the adhesive grooves are formed on an inner peripheral side and an outer peripheral side of the divided core. The electric motor according to claim 1, wherein the adhesive groove is skewed.

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