JP2008125276A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor in which the stator can be secured easily to the motor housing such that they are not loosened by vibration or external impact. <P>SOLUTION: A recess 53 is provided in the inner circumferential surface of the motor housing 2 and a trench 50 having a skew angle is provided at a part corresponding to the recess 53 of the stator 3 being secured in the motor housing 2. A locking member 60 of the stator 3 is inserted into the recess 53 and the trench 50. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brushless motor having a stator detent member.

In general, a brushless motor is composed of a rotor provided with a magnet and a stator having a stator core around which a coil is wound, and the rotor is rotated by controlling energization of the coil. It has become.
Here, the brushless motor is configured to have a predetermined skew angle so that the teeth of the stator core are inclined while being twisted with respect to the axial direction in order to suppress vibration caused by uneven rotation. There is what I did. As such a stator iron core, a laminate obtained by laminating electromagnetic steel sheets punched into a substantially ring shape by press working while being gradually shifted in the circumferential direction is used. By doing in this way, the teeth part which inclines with respect to an axial direction can be manufactured integrally.

Moreover, in this kind of stator core, in order to make it easy to wind a coil around a tooth portion, there is one in which a laminated core including the tooth portion is divided in the circumferential direction along the axial direction. In this way, since the stator core can be assembled after winding the coil for each of the divided laminated cores, the space factor of the coil in the space formed in the stator core can be improved. (For example, refer to Patent Document 1).
JP 2006-33989 A

By the way, in the above-described prior art, in order to fix the stator in the motor housing, the stator is press-fitted or bonded into the motor housing.
However, when the stator is press-fitted and fixed to the motor housing, not only the press-fitting equipment is required, but it is necessary to process the stator and the motor housing with high precision in order to manage the press-fitting allowance. There is a problem that there is.
In addition, there is a problem that the fixing between the motor housing and the stator may be loosened due to vibration, external impact, or the like in the press-fitting and adhesive fixing.

  Accordingly, the present invention has been made in view of the above-described circumstances, and can easily fix the stator to the motor housing, and can fix the motor housing and the stator due to vibration, external impact, or the like. A brushless motor capable of preventing looseness is provided.

In order to solve the above-mentioned problem, the invention described in claim 1 is provided with a first concave portion on the inner peripheral surface of the motor housing, and a portion corresponding to the first concave portion of the stator fixed in the motor housing. A second recess having a skew angle is provided in the first recess and the second recess, and an anti-rotation member serving as an anti-rotation member for the stator is interposed between the first recess and the second recess.
In this case, as in the invention described in claim 2, the rotation preventing member is formed by integrally forming a first member that fits into the first recess and a second member that fits into the second recess. It may be a thing.

  The invention described in claim 3 is characterized in that teeth portions extending in the radial direction of the stator core constituting the stator are skewed.

  The invention described in claim 4 is characterized in that the stator core can be divided in the circumferential direction along the axis.

  According to the present invention, the stator can be easily fixed to the motor housing by interposing the anti-rotation member between the motor housing and the stator. In addition, since the anti-rotation member is used for fixing, loosening of the fixing between the motor housing and the stator due to vibration or external impact can be prevented.

  Furthermore, the second concave portion provided in the stator has a shape having a skew angle, and by restricting the rotation of the stator in the rotational direction by providing a detent member formed so as to correspond to this. In addition to being able to move, the stator needs to move while twisting along the skew angle of the second recess in order to move in the thrust direction (the axial direction of the brushless motor), and as a result, movement in the thrust direction is also restricted. be able to. For this reason, a stator can be reliably fixed to a motor housing.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the brushless motor 1 is a brushless type motor having a stator 3 fitted in a motor housing 2 and a rotor 4 provided so as to be rotatable with respect to the stator 3. For example, it is used for electric power steering (EPS).
The motor housing 2 has a bottomed cylindrical shape, and the stator 3 is fitted to the peripheral wall 2B of the cylindrical portion. A bearing 5 is press-fitted into the end portion (bottom portion) 2 </ b> A of the motor housing 2 at the center. A rotating shaft 6 of the rotor 4 is rotatably supported on the bearing 5. The opening 52 of the motor housing 2 is closed by the bracket 7.

  The stator 3 has a substantially cylindrical stator core 10, and the coil 12 is wound after the insulating member 11 is mounted on the stator core 10. In the rotor 4, a magnet 13 and a resolver rotor 14 </ b> A of a position detection resolver 14 are arranged in order on a rotating shaft 6. The 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 provided on the bracket 7 on the motor housing 2 side. The terminal 22 has a role of electrically connecting the stator winding of the coil 12 on the stator 3 side and the lead wire 23 drawn from the outer periphery of the bracket 7, and is connected to the outside via the lead wire 23. It is possible to supply current to the coil 12 from the power source. In addition, a bolt hole 24 that is used when the brushless motor 1 is fixed projects from the outer peripheral portion of the bracket 7.

  Here, the stator core 10 uses a split core system that can be split in the circumferential direction. As shown in FIGS. 2 and 3, the laminated core piece 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 in the circumferential direction. The core body 31 extends. The core body 31 is a part that forms an annular magnetic path of the stator core 10 and is a part that fits into the inner peripheral surface of the motor housing 2. The core body 31 has a predetermined skew angle a so as to be inclined while twisting with respect to the longitudinal direction (axial direction) of the stator core 10. Both end portions in the circumferential direction of the core body 31 are connection portions 32A and 32B connected to the other laminated core pieces 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.

On the inner peripheral side of the core body 31, a tooth portion 33, which is a salient pole, extends integrally from the substantially circumferential center toward the center of rotation in the radial direction. The teeth portion 33 is also skewed similarly to the core body 31. An end portion on the inner peripheral side of the teeth portion 33 is an inner peripheral portion 34 extending in the circumferential direction. Two concave portions 35 are formed at the same skew angle as the teeth portion 33 on the inner peripheral surface of the inner peripheral portion 34, and three teeth are formed for one laminated iron core piece 30 by the two concave portions 35. Has been.
On the outer peripheral side of the core body 31, a groove 50 is formed at substantially the center in the circumferential direction over the entire longitudinal direction (vertical direction in FIG. 2) of the core body 31. The groove 50 is also skewed similarly to the core body 31. The groove 50 is formed in a U-shaped cross section, and has a bottom wall 51A formed in a direction along the outer peripheral surface of the core body 31, and a pair of side walls 51B and 51B rising from the bottom wall 51A. Yes.

  On the other hand, as shown in FIG. 4, a plurality of recesses 53 are formed in the opening 52 of the motor housing 2 in a portion corresponding to the groove 50 of the core body 31. The recess 53 is formed in a substantially pentagonal shape in plan view, and includes a peripheral wall 54A formed in a direction along the peripheral wall 2B of the motor housing 2 and a pair of side walls 54B and 54B along the longitudinal direction of the motor housing 2. And an inclined wall 54C extending obliquely from one side wall 54B toward the end portion 2A of the motor housing 2, and a bottom wall 54D straddling the inclined wall 54C and the other side wall 54B. Therefore, the concave portion 53 is formed so as to taper as it goes toward the end portion 2 </ b> A of the motor housing 2. The inclined angle b of the inclined wall 54 </ b> C is an angle along the groove 50 formed in the core body 31.

As shown in FIGS. 5 and 6, a recess 53 formed in the motor housing 2 and a groove 50 formed in the core body 31 of the stator core 10 are used to fix the stator 3 to the motor housing 2. An anti-rotation member 60 is interposed.
The rotation preventing member 60 is integrally formed with a first member 61 corresponding to the shape of the recess 53 formed in the motor housing 2 and a second member 63 corresponding to the shape of the groove 50 formed in the core body 31. It has been done.

  The first member 61 is a plate-like member formed in a substantially pentagonal shape in plan view, and is set to a size that can move in the vertical and horizontal directions on the concave portion 53. The first member 61 is formed in the direction along the side wall 62A, 62A formed in the direction along the side wall 54B of the recess 53 of the motor housing 2, the slope 62B formed in the direction along the inclined wall 54C, and the bottom wall 54D. And has a bottom surface 62C. The dimension E1 in the thickness direction of the first member 61 is set to be smaller than the dimension E2 in the depth direction of the recess 53.

On the other hand, the second member 63 is formed to have a substantially rectangular cross-section, and has an inclined portion 64 inclined corresponding to the groove 50 of the core body 31 and the side wall 54B of the recessed portion 53 from the upper end of the inclined portion 64. And a rising portion 65 formed so as to follow. That is, the rotation preventing member 60 is formed in a substantially L shape when viewed from above. A dimension E3 in the width direction of the inclined portion 64 and the rising portion 65 is set to be smaller than a dimension E4 in the width direction of the groove 50.
Further, the dimension E5 in the thickness direction of the rotation preventing member 60 is the dimension E2 in the depth direction of the recess 53 of the motor housing 2, the dimension E6 in the depth direction of the groove 50 of the core body 31, and the motor housing 2 and the core body 31. The clearance C is set to be smaller than the combined dimension.

Next, a method of fixing the motor housing 2 and the stator 3 using the rotation preventing member 60 will be described with reference to FIGS.
As shown in FIG. 7, first, the stator 3 is fitted to the motor housing 2. At this time, the inclined wall 54C of the recess 53 formed in the motor housing 2 and the side wall 51B of the groove 50 formed in the stator core 10 are fitted so as to be on the same line.

  Next, the rotation preventing member 60 is inserted from the opening 52 side of the motor housing 2 (see FIG. 7). At this time, the first member 61 of the rotation preventing member 60 is brought into contact with the peripheral wall 54a of the recess 53, and the inclined portion 64 of the rotation preventing member 60 is brought into contact with the inclined wall 54C of the recess 53. Then, the anti-rotation member 60 is moved along the inclined wall 54C of the recess 53 toward the stator 3 (in the direction of arrow D in FIG. 7).

  Then, the rotation preventing member 60 is inserted between the recess 53 and the groove 50. The anti-rotation member 60 is pushed into the stator core 10 until the bottom surface 62C thereof contacts the bottom wall 54D of the recess 53, and is in a state of being interposed between the recess 53 and the groove 50 (see FIG. 8). At this time, the state in which the first member 61 of the rotation preventing member 60 is fitted to the recess 53, that is, the side surface 62 </ b> B of the rotation preventing member 60 and the side wall 54 </ b> B of the recess 53 are The inclined wall 54C is in contact with each other. Further, the inclined portion 64 of the rotation preventing member 60 is in a state of being fitted in the groove 50 of the stator core 10, that is, in a state of being substantially housed in the groove 50.

In this state, an adhesive or the like is applied between the rotation preventing member 60 and the recess 53 and the groove 50 to fix the rotation preventing member 60. Thus, the anti-rotation member 60 is prevented from coming out of the recess 53 and the groove 50 by applying the adhesive.
The timing of applying the adhesive may be after the anti-rotation member 60 is fitted into the recess 53 and the groove 50, or the adhesive is applied in advance to the outer surface corresponding to the recess 53 and the groove 50 of the anti-rotation member 60. May be. Moreover, you may fix the rotation prevention member 60 using the coating material which coats the coil 12, without using an adhesive agent. That is, after fixing the stator 3 to the motor housing 2, there is a step of applying a coating material to the coil 12. Then, if a coating material is applied to the anti-rotation member 60, the anti-rotation member 60 can be fixed. . In this way, the work process can be shortened.

Therefore, according to the above-described embodiment, the anti-rotation member 60 and the groove 50 interfere with each other and the anti-rotation member 60 and the recess 53 interfere with each other even if the stator 3 tries to move in the rotation direction. The movement in the rotation direction can be restricted.
Further, since the groove 50 of the core body 31 has a skew angle and the second member 63 of the rotation preventing member 60 is formed so as to correspond to this, the stator 3 is in the thrust direction (the axial direction of the brushless motor 1). To move to), it is necessary to move while twisting along the second member 63. However, since the movement of the stator 3 in the rotation direction is restricted, the movement in the thrust direction is also restricted as a result.
Therefore, the stator 3 can be securely fixed in the motor housing 2, and even if vibration or an external impact is applied to the brushless motor 1, the fixing of the motor housing 2 and the stator 3 is prevented from loosening. can do.

Furthermore, since the stator 3 is fixed to the motor housing 2 using the anti-rotation member 60 as described above, the stator 3 is not simply press-fitted and fixed to the motor housing 2 or is adhesively fixed. The stator 3 is fixed to the motor housing 2. For this reason, it becomes possible to fix the stator 3 to the motor housing 2 by using, for example, an adhesive and the anti-rotation member 60 in combination, and a fail safe function can be added at low cost.
Here, fail-safe means that a failure of a part or a system is surely a safe side, or at least almost certainly a safe side (that is, a possibility of a dangerous side failure is extremely low). Means that.

  Then, the stator 3 is fixed to the motor housing 2 simply by fitting the rotation preventing member 60 into the recess 53 formed in the motor housing 2 and the groove 50 formed in the core body 31 of the stator core 10. Can do. For this reason, it is not necessary to press-fit the stator 3 into the motor housing 2, and not only the press-fitting equipment is unnecessary, but also the stator 3 and the motor housing 2 are processed with high accuracy in order to manage the press-fitting allowance. There is no need. Therefore, the processing cost can be reduced.

Further, since the peripheral wall 54A of the recess 53 and the inclined wall 54C function as a guide when the anti-rotation member 60 is inserted between the recess 53 and the groove 50, the anti-rotation member 60 can be easily inserted into the recess 53 and the groove 50. Can be fitted. For this reason, working efficiency can be improved.
Furthermore, since the anti-rotation member 60 has a simple shape, it can be produced, for example, by sintering, and the cost for producing the anti-rotation member 60 can be reduced.
Since the concave portion 53 of the motor housing 2 has a simple shape, for example, when the motor housing 2 is formed by aluminum die casting or the like, the concave portion 53 can be formed without cutting. The cost for forming can be reduced.

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.
Moreover, although the above-mentioned embodiment demonstrated the case where the several recessed part 53 was formed in the opening part 52 of the motor housing 2, it is not restricted to this, The part corresponding to the groove | channel 50 of the core main body 31 is demonstrated. The recessed part 53 should just be formed in at least 1 place of them.

  Furthermore, in the above-described embodiment, after the stator 3 is fitted to the motor housing 2, the stator 53 is rotated around the recess 53 formed in the motor housing 2 and the groove 50 formed in the core body 31 of the stator core 10. The case where the stopper member 60 is fitted has been described, but the attachment procedure of the stopper member 60 is not limited to this, and after the stopper member 60 is attached to the groove 50 of the core body 31 in advance, the stator 3 is attached. The motor housing 2 may be fitted.

  And in the above-mentioned embodiment, although the case where the groove | channel 50 was formed in the outer peripheral side of the core main body 31 over the whole longitudinal direction of the core main body 31 was demonstrated, the site | part in which the groove | channel 50 is formed is restricted to this. Instead, it is only necessary to form a groove 50 that can fit the portion corresponding to the recess 53 of the motor housing 2, that is, the oblique portion 64 of the rotation preventing member 60.

It is sectional drawing which shows the structure of the brushless motor in embodiment of this invention. It is a perspective view of the stator core in the embodiment of the present invention. It is a perspective view of the laminated iron core piece in the embodiment of the present invention. It is a section perspective view of a motor housing in an embodiment of the present invention. It is an expanded sectional view which shows the assembly | attachment state of the detent | locking member in embodiment of this invention. It is a perspective view of the detent | locking member in embodiment of this invention. It is explanatory drawing which shows the assembly | attachment procedure of the rotation prevention member in embodiment of this invention. It is explanatory drawing which shows the assembly | attachment procedure of the rotation prevention member in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Motor housing 2B Perimeter wall 3 Stator 10 Stator core 30 Laminated core piece 33 Teeth part 50 Groove (2nd recessed part)
53 Recessed part (first recessed part)
60 Detent member 61 First member 63 Second member

Claims (4)

  A first recess is provided on the inner peripheral surface of the motor housing, and a second recess having a skew angle is provided at a portion corresponding to the first recess of the stator fixed in the motor housing. A brushless motor characterized in that a rotation-preventing member for preventing rotation of the stator is interposed in the recess.   2. The anti-rotation member according to claim 1, wherein a first member that fits into the first recess and a second member that fits into the second recess are integrally formed. Brushless motor.   The brushless motor according to claim 1 or 2, wherein a tooth portion extending in a radial direction of a stator core constituting the stator is skewed.   The brushless motor according to any one of claims 1 to 3, wherein the stator core can be divided in the circumferential direction along an axis.

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