JP2009130966A - Motor rotor and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor rotor, which has vibration-proof structure where the concentricity is less apt to drop, and a motor. <P>SOLUTION: The motor rotor 3 is equipped with an annular outer core 35, where a permanent magnet 33M is provided at its peripheral face, an annular inner core 34, which is arranged inside this outer core 35 and in which a shaft 32 is fitted in its inner peripheral face; and an elastic body 38, which is interposed in a circular storage 36 that is formed by the inner peripheral face of the outer core 35 and the peripheral face of the inner core 34. The storage 36 has a plurality of minute clearances sections 36a; the radial width of each of which becomes minute; and for these minute clearance sections 36a, each of the clearance width changes continuously in its circumferential direction. The elastic body 38 acts as a shock-absorbing material which absorbs the vibration generated in a motor rotor 3. Slippage of concentricity between the outer core 35 and the inner core 34 can be minimized by the minute clearance section 36a. Since the clearance width of the minute clearance section 36a changes continuously in its circumferential direction, vibration is less apt to propagate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor and a motor rotor mounted on various electric devices such as a fan motor in an outdoor unit of an air conditioner.

  Motors used for fan motors and the like in outdoor units of air conditioners have been improved in efficiency in response to requests for energy saving, and replacement of AC motors with DC brushless motors is progressing. However, since the DC brushless motor generates vibration due to cogging torque and ripple vibration due to energization of the stator, noise may occur when mounted on an actual machine. As a countermeasure against the noise, there is known a method of adopting a vibration isolation structure in which an elastic body such as rubber or elastomer is embedded in the motor rotor (see Patent Documents 1 to 5).

  For example, Patent Document 1 has a configuration in which an iron core of a motor rotor is divided into an inner side and an outer side, and an elastic body is fitted into an annular gap formed therebetween. In Patent Documents 2 to 4, the elastic body is integrally formed by injection molding in an annular gap formed between the inner and outer cores obtained by dividing the iron core at the same time. Furthermore, in patent document 5, it is the structure which connects a part of inner side and an outer side only by connecting only the upper and lower ends of an iron core.

Japanese Patent No. 3689877 JP 2004-297935 A JP 59-86444 A Japanese Patent No. 3364960 JP 2005-348513 A

  As in Patent Documents 1 to 4, in the configuration in which the iron core of the motor rotor is divided into the inner side and the outer side, the vibration generated in the motor rotor is absorbed by the elastic body, so that the vibration is difficult to propagate to the shaft. It becomes composition. However, it is difficult for such an iron core to simultaneously satisfy the effects of absorbing vibration and ensuring the coaxiality between the inner core and the outer core. When the coaxiality of both cores is lowered, the dynamic balance of the motor rotor is lowered, the rotation becomes unstable, and vibration and noise are generated.

  The present invention has been made in view of the above-described known technology, and an object of the present invention is to provide a motor rotor and a motor having a vibration isolation structure in which the coaxiality is unlikely to decrease.

  A motor rotor according to a first aspect of the present invention is a rotor of a motor, and is an annular outer core provided with a permanent magnet on an outer peripheral surface, and is disposed inside the outer core and has a shaft on an inner peripheral surface. And an elastic body interposed in an annular housing portion formed by an inner circumferential surface of the outer core and an outer circumferential surface of the inner core. Has a plurality of minute gap portions in which the gap width in the radial direction is minute, and the minute gap portions are characterized in that the gap width continuously changes in the circumferential direction.

  That is, in this motor rotor, the elastic body acts as a buffer material that absorbs vibration generated in the motor rotor. The deviation of the coaxiality between the outer core and inner core can be minimized by the minute gap, but the gap width of the minute gap changes continuously in the circumferential direction, and the path through which vibration propagates is small. Therefore, vibration is difficult to propagate.

  According to claim 2 of the present invention, in the motor rotor according to claim 1, the outer core has a plurality of outer protrusions protruding radially inward at equal intervals in the circumferential direction of the inner peripheral surface. The inner core has a plurality of inner protrusions protruding radially outward between the adjacent outer protrusions at equal intervals in the circumferential direction of the outer peripheral surface.

  According to claim 3 of the present invention, the minute gap portion is formed between a tip surface of the outer convex portion and an outer peripheral surface of the inner core facing the outer convex portion.

  According to a fourth aspect of the present invention, in the motor rotor according to the second or third aspect, the minute gap portion is between a tip surface of the inner convex portion and an inner peripheral surface of the outer core facing the inner convex portion. It is characterized by being formed.

  According to a fifth aspect of the present invention, in the motor rotor according to any one of the first to fourth aspects, at least one of the inner peripheral surface of the outer core and the outer peripheral surface of the inner core is a plan view in the minute gap portion. It is formed by the protrusion which protrudes in a semicircle shape.

  According to Claim 6 of the present invention, in the motor rotor according to any one of Claims 1 to 5, the narrowest part of the gap width of the minute gap part is 0.01 to 1.00 mm. And

  According to a seventh aspect of the present invention, in the motor rotor according to any one of the second to sixth aspects, the number of the outer convex portions and the inner convex portions is a prime number of 5 or more.

  According to Claim 8 of the present invention, in the motor rotor according to any one of Claims 1 to 7, the elastic body flows molten elastomer into a predetermined mold in which the outer core and the inner core are arranged. By solidifying with, the outer core and the inner core are in close contact with each other.

  According to a ninth aspect of the present invention, there is provided a motor, comprising: a stator; and the motor rotor according to any one of the first to eighth aspects, which is rotatably supported with respect to the stator. It is characterized by.

  According to claim 10 of the present invention, there is provided a motor, comprising: a stator; and the motor rotor according to any one of claims 1 to 5 that is rotatably supported with respect to the stator, The gap width g1 of the narrowest portion of the minute gap portion of the rotor is the narrowest gap among the radial gaps formed by the outer peripheral surface of the rotor and the inner peripheral surface of the stator. It is characterized by being smaller than the width g2.

  Since the motor rotor of the present invention has a vibration-proof structure in which the coaxiality is not easily lowered, low vibration and low noise can be realized. In addition, since the motor of the present invention has a motor rotor having a vibration isolation structure in which the coaxiality is unlikely to decrease, low vibration and low noise can be realized.

  An embodiment of a motor rotor and a motor according to the present invention will be described with reference to FIGS. 1 to 5 using a fan motor mounted on an outdoor unit of an air conditioner.

  A motor 1 shown in FIG. 1 is a DC brushless motor, and includes a stator 2 and a motor rotor 3 (hereinafter referred to as a rotor) that is rotatably supported inward in the radial direction of the stator 2. ing. In the stator 2, a coil 23 is wound around nine magnetic pole portions 22 provided on an annular iron core 21 (the number S of poles is 9), and an end portion of the coil 23 is electrically connected to a circuit board 24. The entire surface including the gap between these members is filled with synthetic resin, and the outer frame 25 of the motor 1 is also formed of the synthetic resin.

  In the rotor 3, a cylindrical shaft 32 is press-fitted and fixed to the inner peripheral surface of an annular iron core 31, and eight arcuate plate-shaped magnets 33 are fixed to the outer peripheral surface by an adhesive. Yes. The curvature of the outer peripheral surface of the magnet 33 is larger than the curvature of the inner peripheral surface. The eight magnets 33 constitute a rotor magnet 33M having eight poles P. The iron core 31 is formed by an annular inner core 34 located radially inside, an annular outer core 35 located outside, and an annular gap between the inner core 34 and the outer core 35. And an elastic body 38 interposed in the accommodating portion 36 (details will be described later). The rotor 3 is rotatably supported with respect to the stator 2 by a pair of bearings 4. A fan (not shown) is attached to the tip of the shaft 32, and the fan is also rotated by the rotation of the rotor 3.

  When the coil 23 of the stator 2 is energized in a predetermined manner, a rotating magnetic field is generated from each magnetic pole portion 22, and the magnetic field of the rotor magnet 33M of the rotor 3 acts on this rotating magnetic field to magnetically attract and repel it. The rotor 3 rotates repeatedly.

  Next, a detailed configuration of the rotor 3 will be described. As shown in FIGS. 1 and 2, the inner core 34 is formed by laminating a plurality of silicon steel plates, and an annular portion 34 a centering on a fitting hole into which the shaft 32 is fitted, and an annular portion. It consists of five inner projections 34b projecting radially outward from five circumferentially equidistant locations on the outer circumferential surface of 34a. The inner convex part 34b protrudes with substantially the same width from the base to the tip, and is formed in a substantially T shape in plan view by protruding in an arc shape at the tip. On the other hand, the outer core 35 is also formed by laminating a plurality of silicon steel plates, and an annular portion 35a having an outer peripheral surface to which the rotor magnet 33M is fixed, a circumferential direction of an inner peripheral surface of the annular portion 35a, and the like. It consists of five outer convex portions 35b protruding radially inward from five intervals. The outer convex portion 35b is formed in a substantially I shape in plan view by projecting with substantially the same width from the base to the tip. Further, in the outer core 35, a bulging portion 35c bulging inward in the radial direction is formed at the center portion in the circumferential direction of the inner circumferential surface between the adjacent outer convex portions 35b. The bulging portion 35c has a slight protrusion length compared to the outer convex portions 35b on both sides, and the tip is semicircular in plan view and smoothly connected to the inner peripheral surface.

  As is clear from FIG. 2, the inner core 34 and the outer core 35 are such that the inner protrusion 34b is located between the adjacent outer protrusions 35b, and the center of the inner protrusion 34b is the center of the bulged portion 35c. On the other hand, the outer convex portion 35b is located between the adjacent inner convex portions 34b, and the center of the outer convex portion 35b is the circumferential center of the outer peripheral surface between the inner convex portions 34b. Opposite to.

  That is, the inner convex portion 34b is accommodated in an inward concave portion 35d formed by a pair of adjacent outer convex portions 35b and an annular portion 35a, and the outer convex portion 35b is adjacent to a pair of adjacent inner convex portions 34b. The inner core 34 and the outer core 35 are not in contact with each other so that the concave and convex portions are alternately meshed with each other in the circumferential direction so as to be accommodated in the outward concave portion 34d formed by the annular portion 35a. It is configured.

  The accommodating portion 36 has a configuration in which gaps corresponding to the concave-convex shape in plan view composed of the inner convex portions 34b and the outer convex portions 35b are continuous in an annular shape. The accommodating portion 36 has a first minute gap 36a formed by the inner protrusion 34b and the bulging portion 35c, and a second minute gap formed by the outer protrusion 35b and the outer peripheral surface of the inner core 34. Part 36b. As shown in FIG. 3, in the first minute gap 36a, an inner convex portion 34b having a small curvature of the outer peripheral surface in plan view and a bulging portion 35c having a large curvature of the inner peripheral surface in plan view are opposed to each other in the radial direction. For this reason, the gap width in the radial direction of the first minute gap portion 36a is such that the gap 35c1 formed on the center line L1 passing through the center of the inner convex portion 34b and the bulging portion 35c is the narrowest, and from the center line L1 It forms so that it may become large continuously as it leaves | separates in the circumferential direction. The gap width of the gap 35c1 is g1, the gap width of the second minute gap portion 36b is g3, and the most sandwiched portion (of the radial gaps formed by the outer peripheral surface of the rotor 3 and the inner peripheral surface of the stator 2 ( (Gap formed between the inner circumferential surface of the magnetic pole portion 22 and the center in the circumferential direction of the outer circumferential surface of the magnet 33) g2 and the compression coefficient of the elastic body 38 as t, the first and second minute gap portions The compression amounts of 36a and 36b can be expressed by t · g1 and t · g2, and the relationship between these gaps is g1≈g3 <(g2 / t). For example, when the diameter of the rotor 3 is about 40 mm, g1 is about 0.01 to 1 mm, g3 is about 0.01 to 1 mm, and g2 Is about 0.3 to 1.5 mm.

  The elastic body 38 includes an annular elastic portion 38a provided in the concave and convex accommodating portion 36, an upper elastic portion 38b provided in an annular shape across the upper end surfaces of the inner convex portion 34b and the outer convex portion 35a, and an inner convex portion. It consists of the lower elastic part 38c provided ranging over the lower end surface of the part 34b and the outer side convex part 35a. The elastic body 38 is formed by pouring molten elastomer into a mold in which the inner core 34 and the outer core 35 are arranged, and solidifying the molten elastomer. This elastomer is a thermoplastic elastomer or rubber. Thermoplastic elastomers are advantageous in terms of elastic properties, strength, moldability, durability, cost, and the like. By forming the elastic body 38 in this way, the inner core 34 and the outer core 35 that are not in contact with each other are integrated via the elastic body 38 (this is referred to as an intermediate assembly). Then, the rotor 3 is completed by fixing the shaft 32 and the rotor magnet 33M to the intermediate assembly.

  In such a rotor 3, vibration generated in the rotor 3 is absorbed by the elastic body 38, so that the shaft 32 and the fan attached thereto rotate stably. Thereby, it is possible to prevent the vibration of the rotor 3 from being transmitted to the stator 2 via the bearing 4, and the motor 1 is reduced in vibration and noise.

  By the way, the rotor 3 has a configuration in which the inner core 34 and the outer core 35 are not in contact with each other as described above and are connected by the elastic body 38 that is softer than both cores. When the overload is applied or the hardness of the elastic body 38 at a specific portion is lowered, the coaxiality between the inner core 34 and the outer core 35 may be lowered. As a result, the dynamic balance of the rotor 3 is lowered and unstable rotation occurs, or the rotor 3 comes into contact with the stator 2.

  However, in this rotor 3, even if the inner core 34 and the outer core 35 try to move relatively in the radial direction, a plurality of first and second minute gap portions 36a arranged at equal intervals in the circumferential direction, Since the movement is restricted by any one of 36b, the coaxiality does not drop significantly. That is, the deviation of the coaxiality depends on the amount of compression of the elastic body 38 interposed in the first and second minute gaps 36a and 36b, and becomes t · g1 or t · g3 or less. Since the compression amount t · g1 or t · g3 is smaller than the gap width g3 as described above, the rotor 3 does not contact the stator 2. Further, if the deviation of the coaxiality is equal to or less than t · g1 or t · g3, even if the dynamic balance of the rotor 3 is lowered, the rotation characteristics are not substantially affected.

  As described above, the first minute gap 36 a not only minimizes the relative movement between the inner core 34 and the outer core 35, but also generates vibration generated in one of the inner core 34 and the outer core 35. It is difficult to propagate to. The first minute gap 36a has a low effect of absorbing vibration because the elastic body 38 is thin in the accommodating part 36, but the gap width of the first minute gap 36a continuously changes in the circumferential direction as described above. Therefore, the path through which the vibration generated on one side propagates to the other side is small, and thus the vibration is difficult to propagate.

  Since the elastic body 38 is provided in the accommodating portion 36 in which the gap corresponding to the concavo-convex shape composed of the inner convex portion 34b and the outer convex portion 35b is continuously formed in an annular shape as described above, the inner core 34 and the outer core 35 are provided. The contact area is large. When the frictional resistance between the two is large, the adhesion between the elastic body 38 and the inner core 34 or the outer core 35 becomes strong. Further, since the inner convex portion 34b is accommodated in the concave portion 35d and the outer convex portion 35b is alternately engaged in the circumferential direction so as to be accommodated in the concave portion 34d, the elastic body 38 includes the inner core 34 and the outer core 35. Therefore, the elastic body 38 is not easily broken by being sandwiched not only in the radial direction but also in the circumferential direction. In addition, even if the elastic body 38 breaks during rotation or the close contact between the elastic body 38 and the cores 34 and 35 collapses, one of the inner convex portion 34b and the outer convex portion 35b faces the other. When it rotates, further rotation is restricted. Therefore, although the rotation state becomes unstable, it can be rotated, so that damage to the motor 1 can be minimized.

  Since the number R (5) of the inner convex portions 34b and the outer convex portions 35b of the rotor 3 is a prime number of 5 or more, it is difficult for the rotor 3 to resonate with the cogging torque and the natural frequency.

  As mentioned above, although one embodiment of the motor rotor and motor of the present invention was described, the scope of the present invention is not limited to this, and various modifications are possible.

  For example, in the rotor 3 of the above-described embodiment, only the first minute gap portion 36a is configured such that the radial gap width continuously changes in the circumferential direction, but such a gap shape is changed to the second minute gap portion 36b. (Not shown). Further, as shown in FIG. 4, such a gap shape may be provided in both the first and second minute gap portions 36a and 36b. Further, when the frictional resistance between the inner core 34 and the outer core 35 with respect to the elastic body 38 is large, or when the rotor 3 is low speed and excessive force does not act in the rotation direction, the inner protrusion 34b and the outer protrusion Both 35b (see FIG. 5) or either one (not shown) may be omitted. The elastic body 38 is in close contact with both the cores 34 and 35 by injection molding, but a molded product having a shape corresponding to the accommodating portion 36 may be fitted and fixed.

Sectional drawing which shows one Embodiment of the motor rotor and motor which concern on this invention. The top view seen from the upper part centering on the motor rotor of FIG. The top view which expanded the principal part of the motor rotor of FIG. The top view which shows the modification of one Embodiment of the motor rotor in FIG. The top view which shows the other modification of one Embodiment of the motor rotor in FIG.

Explanation of symbols

1 Motor 2 Stator 21 Iron core (stator side)
22 Magnetic pole part 23 Coil 24 Circuit board 25 Outer frame 3 Rotor 31 Iron core (rotor side)
32 shaft 33 magnet 33M rotor magnet 34 inner core 34a annular portion 34b inner convex portion 35 outer core 35a annular portion 35b outer convex portion 35c bulging portion 35c1 gap 36 accommodating portion 36a first minute gap portion 36b second minute gap portion 38 elastic body 38a annular elastic portion 38b upper elastic portion 38c lower elastic portion 4 bearing

Claims (10)

A motor rotor,
An annular outer core provided with a permanent magnet on the outer peripheral surface;
An annular inner core disposed inside the outer core and fitted with a shaft on the inner circumferential surface;
An elastic body interposed in an annular housing portion formed by the inner peripheral surface of the outer core and the outer peripheral surface of the inner core;
With
The motor rotor according to claim 1, wherein the housing portion includes a plurality of minute gap portions having a minute gap width in the radial direction, and the gap width continuously changes in the circumferential direction. The outer core has a plurality of outer protrusions protruding radially inward at equal intervals in the circumferential direction of the inner peripheral surface,
2. The motor according to claim 1, wherein the inner core has a plurality of inner protrusions protruding outward in a radial direction between the adjacent outer protrusions at equal intervals in the circumferential direction of the outer peripheral surface. Rotor.   3. The motor rotor according to claim 2, wherein the minute gap is formed between a front end surface of the outer convex portion and an outer peripheral surface of the inner core facing the outer convex portion.   4. The motor rotor according to claim 2, wherein the minute gap portion is formed between a front end surface of the inner convex portion and an inner peripheral surface of the outer core facing the inner convex portion.   5. The micro gap is formed by a protrusion in which at least one of an inner peripheral surface of the outer core and an outer peripheral surface of the inner core protrudes in a semicircular shape in plan view. A motor rotor according to claim 1.   The motor rotor according to any one of claims 1 to 5, wherein a narrowest part of the gap width of the minute gap part is 0.01 to 1.00 mm.   The motor rotor according to any one of claims 2 to 6, wherein the number of the outer convex portions and the inner convex portions is a prime number of 5 or more.   The elastic body is in close contact with the outer core and the inner core by pouring and solidifying molten elastomer into a predetermined mold in which the outer core and the inner core are arranged. Item 8. The motor rotor according to any one of Items 1 to 7. A stator,
A motor comprising: the motor rotor according to claim 1, which is rotatably supported with respect to the stator. A stator,
The motor rotor according to any one of claims 1 to 5, which is rotatably supported with respect to the stator,
The gap width g1 of the narrowest portion of the minute gap portion of the rotor is the gap of the narrowest portion of the radial gap formed by the outer peripheral surface of the rotor and the inner peripheral surface of the stator. A motor characterized by being smaller than the width g2.

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