JP2011166984A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise of a motor 10 by suppressing unevenness of tightening force P due to temperature distribution inside the motor 10 when the motor 10 is driven. <P>SOLUTION: The motor 10 includes: a stator core 22 structured with a plurality of split cores 26; a cylindrical body 24, which tightens and fixes the stator core 22; and a case 16, which accommodates and fixes the cylindrical body 24. When a linear expansion coefficient of the cylindrical body 24 is large exceeding that of the stator core 22, the stator core 22 is fixed to the cylindrical body 24 so as to cause the tightening force P to increase gradually as it leaves from fixed areas M in the direction of an axis 38. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor, and more particularly to an improvement in the structure of a stator having a stator core composed of a plurality of divided cores arranged in the circumferential direction.

  The motor has a rotor and a stator disposed around the rotor. The stator has a coil, and a rotating magnetic field is generated when a current flows through the coil. The rotor is rotated by an electromagnetic action acting between the rotating magnetic field and the rotor.

  The stator has a hollow cylindrical stator core. There is an example in which the stator core is composed of a plurality of divided cores arranged in the circumferential direction from the viewpoint of improving manufacturing efficiency including coil formation. The stator core configured as described above is manufactured by inserting divided cores arranged in the circumferential direction into the inner periphery of an annular cylindrical body and shrink-fitting the cylindrical body.

  In the following Patent Document 1, a stator core configured by arranging a plurality of divided cores in an annular shape, a second housing that surrounds the stator core from the periphery, and fastens and fixes the stator core, and accommodates and fixes the second housing An electric motor having a first housing is described. Further, it is shown that a flange portion extending radially outward is formed at an end portion of the second housing in the axial direction, and this flange portion is fixed to the first housing portion via a screw. In this electric motor, a material is used in which the linear expansion coefficient of the second housing is equal to or slightly larger than the linear expansion coefficient of the stator core. As a result, the second housing and the stator core expand or contract at an equal rate in accordance with the temperature change of the drive motor, so that the holding force of the stator core by the second housing can be kept constant.

JP 2009-60760 A

  Normally, when the motor is driven, the stator generates heat. This heat is radiated from the cylindrical body to the outside through a case for housing and fixing the cylindrical body. Then, when the fixed region of the cylinder and the case is the end portion of the cylindrical body in the axial direction as in Patent Document 1, the stator region far from the end is higher in temperature than the stator region near the end. Become. As described above, when a temperature difference occurs in the stator, the tightening force of the cylindrical body against the stator core varies in the stator based on the temperature difference, and the tightening force decreases in a part of the stator. There is a possibility that. When the tightening force decreases, there is a problem that the split core vibrates and the noise of the motor increases.

  An object of the present invention is to provide a motor capable of suppressing vibration of a split core and reducing motor noise with a simple structure.

  The present invention relates to a stator core composed of a plurality of divided cores arranged in the circumferential direction, a cylinder that surrounds the stator core from the periphery, and fastens and fixes the stator core, and a case that accommodates the cylinder and fixes the cylinder When the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the tightening force of the cylindrical body with respect to the stator core gradually increases as the distance from the fixing area of the cylindrical body and the case increases in the axial direction. If the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the clamping force of the cylindrical body against the stator core gradually decreases as the distance from the fixing area between the cylindrical body and the case increases in the axial direction. As described above, the stator core is fixed to the cylindrical body.

  In addition, when the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the stator core is formed such that the outer diameter thereof gradually increases as the distance from the fixing area between the cylindrical body and the case increases in the axial direction. Is preferable.

  Further, when the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the cylindrical body is formed so that the inner diameter thereof gradually decreases as the distance from the fixing area between the cylindrical body and the case increases in the axial direction. Is preferable.

  Further, when the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the stator core is formed so that the outer diameter thereof gradually decreases as the distance from the fixing area between the cylindrical body and the case increases in the axial direction. Is preferable.

  Further, when the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the cylindrical body is formed so that the inner diameter thereof gradually increases as the distance from the fixing area of the cylindrical body and the case increases in the axial direction. Is preferable.

  Further, the cylindrical body can have a flange portion that extends radially outward and is fixed to the case at an end portion in the axial direction.

  According to the motor of the present invention, the vibration of the split core can be suppressed and the noise of the motor can be reduced with a simple structure.

It is a figure which shows the structure of the motor which concerns on this embodiment. It is the figure by the AA line of FIG. It is a figure which shows the relationship between the distance from the fixed area | region in an axial direction, and the temperature of a stator at the time of the drive of a motor. It is a figure which shows the clamping force. It is a figure which shows the clamping force at the time of the drive of a motor. It is a figure which shows the clamping force which concerns on another embodiment. It is a figure which shows the clamping force at the time of the drive of the motor which concerns on another embodiment.

  Hereinafter, an embodiment of a motor according to the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a configuration of a motor 10 according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  The motor 10 includes a rotor 12, a stator 14, and a case 16 that accommodates them. The stator 14 is disposed on the inner peripheral surface of the case 16 with a gap, and the rotor 12 is rotatably disposed on the inner periphery of the stator 14.

  The rotor 12 is a cylindrical magnetic body that is concentric with the rotary shaft 18, and is configured by, for example, laminating electromagnetic steel plates in the axial direction. As shown in FIG. 1, eight permanent magnets 20 are arranged on the rotor 12 in the circumferential direction. The number of permanent magnets 20 is an example. In the present embodiment, the permanent magnet 20 is embedded in a hole formed in the rotor 12 so as to extend in the axial direction. However, the present invention is not limited to this, and the permanent magnet 20 may be disposed on the outer periphery of the rotor 12. The rotating shaft 18 is rotatably supported by a bearing (not shown) disposed in the case 16. Further, in the present embodiment, the case where the rotor 12 is configured by stacking electromagnetic steel plates has been described. However, the present invention is not limited to this configuration, and the rotor 12 may be formed from a dust core.

  The stator 14 is disposed around the rotor 12 with a slight gap. The stator 14 has a hollow cylindrical stator core 22, and a cylindrical body 24 that surrounds the stator core 22 from the periphery and fixes the stator core 22. In the present embodiment, the stator core 22 is constituted by a divided core 26 divided in the circumferential direction. Twenty-four divided cores 26 are arranged in the circumferential direction. The number of divided cores 26 is an example.

  The split core 26 is a magnetic body, and is formed, for example, by laminating electromagnetic steel plates in the axial direction. Specifically, the split core 26 is formed by punching a thin plate-shaped electrical steel sheet with a press, laminating a predetermined number of the punched electrical steel sheets in the axial direction, and pressing the plurality of laminated electrical steel sheets with pressure caulking or the like. Formed by processing. In addition, in this embodiment, although the case where the division | segmentation core 26 was comprised by laminating | stacking an electromagnetic steel plate was demonstrated, it is not limited to this structure, Even if the division | segmentation core 26 is shape | molded from a powder magnetic core. Good.

  The stator core 22 is configured by arranging the divided cores 26 formed in this manner in the circumferential direction. The stator core 22 has an annular yoke 22a and teeth 28 that protrude radially inward from the inner periphery of the yoke 22a and are arranged at predetermined intervals in the circumferential direction. A conducting wire is passed through the slot 30 which is a groove-like space between the teeth 28. The conductive wire is wound around the tooth 28 while passing through the slot 30 to form a coil 32 (shown in FIG. 2).

  The cylindrical body 24 has a substantially cylindrical shape, and is formed so that the inner diameter of this shape is smaller than the outer diameter of the stator core 22, that is, considering the tightening allowance. The cylindrical body 24 fastens and fixes the stator core 22 by shrink fitting or press fitting. For example, in the shrink fitting process, after the cylindrical body 24 is heated and expanded, the stator core 22 is accommodated inside thereof. Then, the cylindrical body 24 is thermally contracted by radiating or cooling the cylindrical body 24 and the stator core 22. Due to this thermal contraction, a clamping force P of the cylindrical body 24 against the stator core 22 is generated, and the divided core 26 and the cylindrical body 24 constituting the stator core 22 are firmly and integrally fixed.

  As shown in FIG. 2, the cylindrical body 24 is formed with a flange portion 34 extending radially outward at an end portion in the direction of the shaft 38. The flange portion 34 is fixed to the case 16 via a fastening member 36 such as a bolt. In the present embodiment, the case where the flange portion 34 of the cylindrical body 24 is fixed to the case 16 via the fastening member 36 has been described. However, the present invention is not limited to this configuration, and the flange portion 34 of the cylindrical body 24 is welded. Can also be fixed to the case 16.

  The case 16 has a substantially cylindrical shape. The motor 10 is configured by housing the rotor 12 and the stator 14 in the case 16 and attaching a lid (not shown) that covers one end of the case 16 to the case 16.

  In the motor 10 configured as described above, a rotating magnetic field is generated in the stator 14 by energization of the coil 32, and a force attracted by the rotating magnetic field is generated in the rotor 12 having the permanent magnet 20. Rotate.

  Next, the relationship between the distance L from the fixed region M in the direction of the shaft 38 and the temperature T of the stator 14 when the motor 10 is driven will be described with reference to FIG. Here, the fixed region M is a region where the stator 14 and the case 16 are fixed. In the present embodiment, the region where the cylindrical body 24 and the case 16 are fixed, that is, shown in FIG. A contact portion between the flange portion 34 and the case 16.

  When the motor 10 is driven, the stator 14 generates heat. This heat is radiated from the cylindrical body 24 to the outside through the case 16. In the motor 10 of the present embodiment, as shown in FIG. 2, the fixed region M where the stator 14 and the case 16 are in contact is at the end of the cylinder 24 in the direction of the shaft 38. Then, as shown in FIG. 3, when the relationship between the distance L in the direction of the shaft 38 and the temperature T of the stator 14 is expressed, it becomes difficult to dissipate heat as the distance L increases, that is, as the distance L increases, the temperature T increases. Become. As described above, when a temperature difference occurs in the stator 14, the tightening force P fluctuates in the stator 14 based on the temperature difference, and as a result, the noise of the motor 10 increases. There is a problem of doing.

  Therefore, in the motor 10 of the present embodiment, a material is used in which the linear expansion coefficient α of the cylindrical body 24 exceeds the linear expansion coefficient β of the stator core 22. Specifically, the cylindrical body 24 is formed of a material containing, for example, aluminum, and the stator core 22 is formed of an electromagnetic steel plate as described above.

  In the motor 10 of the present embodiment, the stator core 22 is fixed to the cylindrical body 24 so that the tightening force P gradually increases as the stator core 22 moves away from the fixing region M in the direction of the shaft 38. This configuration will be described with reference to FIG. FIG. 4 is a diagram showing the tightening force P.

  FIG. 4 visually shows how the tightening force P with which the cylindrical body 24 tightens the stator core 22 is distributed in the direction of the shaft 38. According to this figure, the tightening force P gradually increases as the distance from the end on the fixed region M side increases. Such a tightening force P is formed such that the outer diameter of the stator core 22 gradually increases as the stator core 22 moves away from the fixed region M in the direction of the shaft 38, or the inner diameter of the cylindrical body 24 extends from the fixed region M to the shaft. It forms so that it may become small gradually as it leaves | separates to 38 direction, or it achieves by the structure which combined these.

  When the motor 10 having the stator 14 having such a configuration is driven to generate heat, the distribution of the tightening force P as shown in FIG. 5 is obtained. That is, the tightening force P is substantially uniform in the direction of the shaft 38. Because the linear expansion coefficient α of the cylindrical body 24 is larger than the linear expansion coefficient β of the stator core 22, the cylindrical body 24 expands more than the stator core 22 and decreases the tightening force P in the region where the temperature T of the stator 14 is higher. It is because it makes it.

  Thus, by considering the fluctuation of the tightening force P based on the temperature difference in the stator 14 in advance, the stator 14 is configured, so that the tightening force P is extremely reduced in a partial region of the stator 14. Can be prevented. As a result, the vibration of the split core 26 caused by the decrease in the tightening force P can be suppressed, and the noise of the motor 10 can be reduced.

  Next, a motor 10 according to another embodiment will be described with reference to FIGS. FIG. 6 is a diagram illustrating a tightening force P according to another embodiment, and FIG. 7 is a diagram illustrating a tightening force P when the motor 10 according to another embodiment is driven. In addition, the same code | symbol is attached | subjected about the same component as the said embodiment, and detailed description is abbreviate | omitted.

  In the motor 10 of this embodiment, a material is used such that the linear expansion coefficient β of the stator core 22 is larger than the linear expansion coefficient α of the cylindrical body 24. Specifically, the stator core 22 is formed of an electromagnetic steel plate as described above, and the cylindrical body 24 is formed of a material having a smaller linear expansion coefficient than the electromagnetic steel plate, for example, iron.

  In the motor 10 of this embodiment, the stator core 22 is fixed to the cylinder 24 so that the tightening force P gradually decreases as the stator core 22 moves away from the fixing region M in the direction of the shaft 38. This configuration will be described next with reference to FIG.

  FIG. 6 visually shows how the tightening force P with which the cylindrical body 24 tightens the stator core 22 is distributed in the direction of the shaft 38, as in FIG. 4 described above. According to this figure, the tightening force P gradually decreases as the distance from the end on the fixed region M side increases. Such a tightening force P is formed such that the outer diameter of the stator core 22 gradually decreases as the stator core 22 moves away from the fixed region M in the direction of the shaft 38, or the inner diameter of the cylindrical body 24 extends from the fixed region M to the shaft. It is formed so as to gradually increase as it moves away in the 38 direction, or is achieved by a structure in which these are combined.

  When the motor 10 having the stator 14 having such a configuration is driven and the stator 14 generates heat, the distribution of the tightening force P as shown in FIG. 7 is obtained. That is, the tightening force P is substantially uniform in the direction of the shaft 38. Because the linear expansion coefficient β of the stator core 22 is larger than the linear expansion coefficient α of the cylindrical body 24, the stator core 22 expands more than the cylindrical body 24 and the tightening force P increases in the region where the temperature T of the stator 14 is higher. It is because it makes it.

  In this way, by considering the fluctuation of the tightening force P based on the temperature difference in the stator 14 in advance, the stator 14 is configured, so that the tightening force P remains extremely reduced in a partial region of the stator 14. Can be prevented. As a result, the vibration of the split core 26 caused by the decrease in the tightening force P can be suppressed, and the noise of the motor 10 can be reduced.

  10 motors, 12 rotors, 14 stators, 16 cases, 22 stator cores, 24 cylinders, 26 split cores, 34 flanges, 38 axes.

Claims (6)

A stator core composed of a plurality of divided cores arranged in the circumferential direction;
A cylindrical body that surrounds the stator core from the surroundings and tightens and fixes the stator core;
A case for housing the cylinder and fixing the cylinder;
Have
When the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the clamping force of the cylindrical body with respect to the stator core gradually increases as the distance from the fixing area of the cylindrical body and the case increases in the axial direction, or When the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the stator core is arranged so that the clamping force of the cylindrical body against the stator core gradually decreases as the distance from the fixing area between the cylindrical body and the case increases in the axial direction. Fixed to the cylinder,
A motor characterized by that. The motor according to claim 1,
When the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the stator core is formed such that the outer diameter thereof gradually increases as the distance from the fixing area of the cylindrical body and the case increases in the axial direction.
A motor characterized by that. The motor according to claim 1 or 2,
When the linear expansion coefficient of the cylindrical body is larger than the linear expansion coefficient of the stator core, the cylindrical body is formed so that the inner diameter thereof gradually decreases as it moves away from the fixing area of the cylindrical body and the case.
A motor characterized by that. The motor according to claim 1,
When the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the stator core is formed so that the outer diameter thereof gradually decreases as the distance from the fixing area of the cylindrical body and the case increases in the axial direction.
A motor characterized by that. The motor according to claim 1 or 4,
When the linear expansion coefficient of the stator core is larger than the linear expansion coefficient of the cylindrical body, the cylindrical body is formed such that the inner diameter thereof gradually increases as the distance from the fixing region of the cylindrical body and the case increases in the axial direction.
A motor characterized by that. The motor according to any one of claims 1 to 5,
The cylindrical body has a flange portion that extends radially outward and is fixed to the case at an end portion in the axial direction.
A motor characterized by that.

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