JP2020018110A - Brushless motor - Google Patents

Abstract

To provide a brushless motor having an anti-vibration structure applicable to large motors of large output.SOLUTION: The brushless motor 100 includes a stator 20 in which a winding 24 is wound around a stator core 22 and a rotor 30 positioned opposite to the stator 20. The rotating body 34 includes a plurality of magnets 36 and an elastic layer 38. The plurality of magnets 36 is annularly located around the axis J in the circumferential direction. The elastic body layer 38 is annularly located along the axis J between the rotating shaft 32 and the plurality of magnets 36 and is formed of a plurality of granular elastic bodies 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to prevention of vibration of a brushless motor.

  In recent years, for example, in an air conditioner and a device for circulating a liquid, a so-called chiller, a highly efficient brushless motor is often used for the purpose of reducing power consumption. In the following description, the brushless motor may be simply referred to as a motor.

  By the way, noise may be generated in a brushless motor used for a fan motor or the like. That is, in the brushless motor, vibration due to cogging torque and ripple vibration generated when current is supplied to the windings of the brushless motor occur. These vibrations may generate noise when the brushless motor is incorporated in a product body such as a fan motor.

  Therefore, various measures have conventionally been taken to prevent this noise. For example, there is one in which a rotor provided in a brushless motor is provided with an anti-vibration structure (for example, see Patent Document 1).

  More specifically, as shown in FIGS. 8 to 10, the rotor 230 of the conventional brushless motor 200 has the following vibration-proof structure.

  FIG. 8 is a half sectional view showing the structure of a conventional brushless motor. FIG. 9 is a front view of a rotating body of a rotor included in a conventional brushless motor viewed from an axial direction. FIG. 10 is a sectional view taken along line 10-10 in FIG.

  That is, the rotor 230 is formed by the rotating body 234 and the rotating shaft 32. The rotating body 234 includes an inner rotor core 44 and a resin molded part 238 in order from the axis J toward the outer periphery in the radial direction along the axis J serving as the center of the insertion hole 32b into which the rotating shaft 32 is inserted. And an outer rotor core 42 and a magnet 36.

  The inner rotor core 44 is fixed to the rotating shaft 32 inserted into the insertion hole 32b. The resin molded portion 238 can be molded with rubber or a thermoplastic elastomer. The outer rotor core 42 forms a magnetic path using the magnetic flux emitted from the magnet 36. The magnet 36 is located on the outer peripheral surface of the rotor 230. The magnets 36 are located on the outer periphery of the outer rotor core 42 and are attached at equal intervals in a circumferential direction around the axis J. As the magnet 36, a ferrite sintered magnet can be used.

  The rotating body 234 is integrally formed of a resin material injected between the inner rotor core 44 and the outer rotor core 42. The injected resin material forms a resin molded part 238. According to this configuration, the rotating body 234 prevents the components held therein from coming off and secures strength against rotation. The rotating shaft 232 of the rotating body 234 is inserted into an insertion hole 32b formed in the axis J direction.

JP 2004-297935 A

  However, the conventional rotor has the following problems.

  In other words, a structure in which a resin material is injected between the inner rotor core and the outer rotor core and the inner rotor core, the outer rotor core, and a plurality of magnets are integrally molded by the resin molding portion is excellent in a motor having a small output. It is effective.

  However, when the same structure is diverted to a motor having a large output, the weight of the rotating body becomes heavy, and there is a problem that the resin molded portion buckles due to its own weight.

  In other words, when the conventional rotating body structure is applied to a small motor having a small output, a resin molded portion serving as an elastic body is located between a magnet that generates vibration and a rotating shaft that transmits torque. A sufficient anti-vibration effect can be obtained.

  However, when the structure of the conventional rotating body is applied to a large motor having a large output, the weight of the rotating body becomes too large, so that the resin material forming the resin molded portion cannot withstand the weight of the rotating body and buckling. Or breakage. Therefore, it has been difficult to adopt the conventional structure of the rotating body as an anti-vibration structure for a large-sized motor having a large output.

  The present invention solves the above-mentioned problems, and provides a vibration-proof structure of a brushless motor that has a large output and can be used for a large motor.

  A brushless motor according to the present invention includes a stator having windings wound around a stator core, and a rotor positioned to face the stator. The rotor has a rotating shaft extending in the axial direction and a rotating body extending in the axial direction and attached to the rotating shaft.

  Further, the rotating body includes a plurality of magnets and an elastic body layer. The plurality of magnets are annularly located in a circumferential direction around the axis. The elastic body layer is annularly located along the axis between the rotating shaft and the plurality of magnets, and is formed of a plurality of granular elastic bodies.

  With the above configuration, the brushless motor of the present invention can adjust the amount of the plurality of granular elastic bodies sealed in the elastic body layer and change the filling rate of the elastic body in the elastic body layer.

  Therefore, the brushless motor of the present invention obtains a rotor having both vibration isolation performance and strength required by each motor from small motors to large motors according to the output required of the motor. Can be.

Half sectional view showing the structure of the brushless motor according to Embodiment 1 of the present invention. The front view which looked at the rotating body which the rotor with which the brushless motor concerning Embodiment 1 of this invention is provided with has from axial direction. 2 is a sectional view taken along line 3-3 in FIG. 3 is a sectional view taken along line 4-4 in FIG. Longitudinal sectional view of a rotating body used in an air conditioner according to Embodiment 2 of the present invention. 5 is a sectional view taken along line 6-6. Longitudinal sectional view of a rotating body used for an air conditioner according to Embodiment 3 of the present invention. Half-sectional view showing the structure of a conventional brushless motor Front view of a rotating body of a rotor included in a conventional brushless motor viewed from an axial direction 9 is a cross-sectional view taken along line 10-10.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiment is an example that embodies the present invention, and does not limit the technical scope of the present invention.

(Embodiment 1)
FIG. 1 is a half sectional view showing a structure of a brushless motor 100 according to Embodiment 1 of the present invention. FIG. 2 is a front view of the rotating body 34 of the rotor 30 included in the brushless motor 100 according to Embodiment 1 of the present invention as viewed from the axis J direction. FIG. 3 is a sectional view taken along line 3-3 in FIG. FIG. 4 is a sectional view taken along line 4-4 in FIG.

  As shown in FIGS. 1 to 4, a brushless motor 100 according to an embodiment of the present invention includes a stator 20 in which a winding 24 is wound around a stator iron core 22, and a rotation that faces the stator 20. And a child 30. The rotor 30 has a rotating shaft 32 extending in the direction of the axis J, and a rotating body 34 extending in the direction of the axis J and attached to the rotating shaft 32.

  Further, the rotating body 34 includes a plurality of magnets 36 and an elastic layer 38. The plurality of magnets 36 are annularly located around the axis J in the circumferential direction. The elastic layer 38 is annularly located along the axis J between the rotating shaft 32 and the plurality of magnets 36 and is formed of a plurality of granular elastic bodies 40.

  In particular, configurations that exhibit remarkable effects are as follows.

  That is, the plurality of granular elastic bodies 40 have different dimensions and shapes.

  The filling rate of the elastic layer 38 is changed by adjusting the injection amount of the plurality of granular elastic bodies 40.

  Alternatively, the rotating body 34 includes an outer rotor core 42 that is a first rotor core positioned annularly along the axis J between the elastic body layer 38 and the plurality of magnets 36.

  The rotating body 34 includes an inner rotor core 44 that is a second rotor core positioned annularly along the axis J between the elastic layer 38 and the rotating shaft 32.

  The rotating body 34 includes a resin portion 46 for fixing at least a plurality of magnets 36, an elastic body layer 38, and an outer rotor core 42 that is a first rotor core.

  Hereinafter, this will be described in detail with reference to the drawings.

  As shown in FIG. 1, a brushless motor 100 according to the first embodiment exemplifies an inner rotor type motor in which a rotor 30 is located inside a stator 20.

  In the stator 20, an insulator 26, which is an insulating member, is attached between the stator core 22 and the winding 24. The insulator 26 is mainly formed of a resin material. The stator core 22 is configured by stacking a plurality of electromagnetic steel plates in the direction of the axis J. A predetermined current is applied to the winding 24 to generate a magnetic force for driving the rotor 30. As the winding 24, a copper wire, an aluminum wire, or a wire material obtained by combining these can be used.

  The rotor 30 is located inside the stator 20 so as to face the rotor 30. The rotor 30 includes an output shaft 32a as a part of the rotation shaft 32. When the brushless motor 100 is incorporated in a fan motor, a fan is attached to the output shaft 32a. The rotating shaft 32 is inserted into the insertion hole 32b of the rotating body 34. The rotor 30 is rotatably supported by a pair of bearings 50 attached to the rotating shaft 32 with the rotating body 34 interposed therebetween. In the first embodiment, the bearing 50 has a ball-shaped rolling element 50a, and an inner ring 50b and an outer ring 50c that hold the rolling element 50a therebetween. The inner ring 50b is attached to the rotation shaft 32. Each outer race 50c is fixed to a respective bracket 28 forming the outer shell of the motor 100.

  The outer rotor core 42 and the inner rotor core 44 of the rotating body 34 are formed by laminating a plurality of electromagnetic steel plates in the direction of the axis J. A plurality of magnets 36 are attached to the outer peripheral side of the outer rotor core 42, that is, a surface facing the stator 20. As the magnet 36, a ferrite sintered magnet can be used. The resin part 46 fixes the magnet 36 to the rotating body 34.

  A plurality of elastic bodies 40 formed in a granular shape are sealed in the elastic body layer 38. A lid 52 that closes one end of a space where the elastic layer 38 is formed is attached to the elastic layer 38 on the side opposite to the output shaft. A resin portion 46 is attached to the output shaft side of the elastic layer 38 to close the other end of the space where the elastic layer 38 is formed.

  The resin portion 46 is fixed such that the inner rotor core 44 and the outer rotor core 42 do not come into contact with each other. Specifically, the resin portion 46 forms a basic skeleton of the rotating body 34. The basic skeleton of the rotating body 34 keeps the inner rotor core 44 and the outer rotor core 42 out of contact with each other. In the basic skeleton of the rotating body 34, a hollow portion forming the elastic layer 38 is formed between the inner rotor core 44 and the outer rotor core 42. An elastic body 40 functioning as a vibration damping material, a so-called damping material, is sealed in the hollow portion forming the elastic body layer 38. Therefore, the rotating body 34 is formed in a structure in which the outer peripheral side forming the magnet part and the inner peripheral side attached to the rotating shaft 32 are not in contact with each other. An elastic body 40 functioning as a damping material is located between the outer peripheral side and the inner peripheral side. The elastic body 40 is filled at a filling rate according to the physique of the rotor 30. Therefore, the elastic body 40 can insulate the outer peripheral side and the inner peripheral side, and can appropriately provide vibration isolation required according to the physique of the rotor 30.

  In other words, the plurality of magnets 36 arranged in a cylindrical shape and the inner rotor core 44 attached to the rotating shaft 32 are held by the resin portion 46 having the minimum strength required for the rotor 30 according to the physique. Is done. With this configuration, since the vibration generated by the magnet 36 is suppressed by the elastic layer 38, it is possible to prevent the vibration from being transmitted to the rotating shaft 32 that transmits the torque. Therefore, if the rotor is used, a brushless motor with low vibration can be provided.

  As shown in FIGS. 3 and 4, a plurality of elastic members 40 having different dimensions are enclosed in the elastic layer 38. In the first embodiment, the ball-shaped elastic body 40 is sealed. According to this configuration, since the dimensions of the elastic bodies 40 to be enclosed are different, the elastic bodies 40 of a small size enter between the elastic bodies 40 of a large dimension. Therefore, the elastic body 40 sealed in the elastic body layer 38 can obtain a proper filling condition.

  As will be described later, the elastic body 40 sealed in the elastic body layer 38 can have other shapes and various dimensions as long as required vibration-proof performance can be secured. In addition, various materials can be used according to the purpose.

  Further, the plurality of elastic bodies 40 sealed in the elastic body layer 38 are required to be in an appropriate sealed state so that the plurality of elastic bodies 40 can move slightly when the motor is driven. In other words, the state in which the plurality of elastic bodies 40 sealed in the elastic body layer 38 in the first embodiment are in close contact with each other and cannot move when the motor is driven is excluded. The index indicating the sealed state is also called a filling rate.

  The brushless motor 100 according to the first embodiment adjusts the material, shape, size, and filling rate of the plurality of elastic bodies 40 enclosed in the elastic body layer 38, so that the size of the plurality of elastic bodies 40 ranges from a small motor to a large motor. By appropriately satisfying the required anti-vibration performance, the basic configuration and materials can be shared.

  In other words, according to the use state of the product in which the brushless motor 100 according to the first embodiment is incorporated, the brushless motor 100 can appropriately adjust the suppression frequency so as to obtain the damping frequency corresponding to the generated resonance frequency. . Here, the use state of the product to be considered includes the following. For example, there is an attached state of the air conditioner to an indoor unit or an outdoor unit, and an operation state thereof. In addition, there is rigidity when the motor is attached to the housing constituting the main body. In addition, there is a shape of a fan attached to an output shaft of the motor. Therefore, the brushless motor 100 according to the first embodiment can obtain the required quietness and vibration suppression.

(Embodiment 2)
Second Embodiment A brushless motor according to a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 5 is a longitudinal sectional view of a rotating body used in the air conditioner according to Embodiment 2 of the present invention. FIG. 6 is a sectional view taken along line 6-6 in FIG.

  In addition, about the structure similar to the brushless motor in Embodiment 1, the same code | symbol is attached | subjected and description is used.

  As shown in FIGS. 5 and 6, the difference between the rotating body 34a used in the brushless motor according to one embodiment of the present invention and the rotating body 34 described in the first embodiment is that the elastic layer 38, This is a point that the inner rotor core 44 that is the second rotor core positioned annularly along the axis J is not included between the rotating shaft 32 and the rotating shaft 32.

  In other words, the rotating body 34a according to the second embodiment includes the plurality of magnets 36 and the elastic layer 38. The plurality of magnets 36 are annularly located around the axis J in the circumferential direction. The elastic layer 38 is annularly located along the axis J between the rotating shaft 32 and the plurality of magnets 36 and is formed of a plurality of granular elastic bodies 40.

  Here, the plurality of granular elastic bodies 40 have different dimensions and shapes, respectively.

  The filling rate of the elastic layer 38 is changed by adjusting the injection amount of the plurality of granular elastic bodies 40. The rotating body 34 includes an outer rotor core 42 that is a first rotor core positioned annularly along the axis J between the elastic body layer 38 and the plurality of magnets 36. The rotating body 34 includes a resin portion 46 for fixing at least a plurality of magnets 36, an elastic body layer 38, and an outer rotor core 42 that is a first rotor core.

  That is, when the resin portion 46 forming the basic skeleton of the rotating body 34a has sufficient strength, the rotating body 34a can be attached to the rotating shaft 32 by the resin portion 46 instead of the inner rotor core 44.

  With this configuration, since the inner rotor core 44 can be eliminated, the workability is improved, for example, the step of pressing the inner rotor core 44 into the rotating shaft 32 can be omitted.

(Embodiment 3)
Third Embodiment A brushless motor according to a third embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a longitudinal sectional view of a rotating body 34b used in the air conditioner according to Embodiment 3 of the present invention.

  In addition, about the structure similar to the brushless motor in this Embodiment 1, 2, the same code | symbol is attached | subjected and description is used.

  As shown in FIG. 7, in the rotating body 34b used in the brushless motor according to one embodiment of the present invention, the size of the elastic body 40 sealed in the elastic body layer 38 is uniform.

  With this configuration, since only one kind of elastic body 40 to be sealed needs to be prepared, inventory management is facilitated and productivity is improved.

  As is apparent from the above description, the brushless motor according to the embodiment of the present invention has a granular shape between the outer rotor core having a plurality of magnets attached to the outer peripheral side and the inner rotor core fixed to the rotating shaft. It has an elastic layer in which the elastic body is sealed.

  By adjusting the material, size, shape, filling rate, and the like of the elastic body sealed in the elastic body layer, it is possible to obtain a rotating body having vibration damping properties at various frequencies. Therefore, by using the rotating member, it is possible to provide a brushless motor having anti-vibration properties and low noise for various uses using the same member.

  The brushless motor according to the present invention can be applied to a heavy-weight, high-output motor. Therefore, it is particularly effective for a commercial air conditioner represented by a large output air conditioner or chiller.

Reference Signs List 20 stator 22 stator core 24 winding 26 insulator 28 bracket 30, 230 rotor 32 rotation shaft 32a output shaft 32b insertion hole 34, 34a, 34b, 234 rotation body 36 magnet 38 elastic layer 40 elastic body 42 outer rotor core ( 1st rotor core)
44 Inner rotor core (second rotor core)
46 Resin part 50 Bearing 50a Rolling element 50b Inner ring 50c Outer ring 52 Lid 100, 200 Motor (brushless motor)
238 Resin molding

Claims (5)

A stator with windings wound around the stator core,
Located facing the stator,
A rotating shaft extending in the axial direction,
A rotating body extending along the axial direction and attached to the rotating shaft,
A rotor having
With
The rotating body is
A plurality of magnets, which are annularly located in a circumferential direction around the axis,
An elastic layer formed of a plurality of granular elastic bodies, which is annularly positioned along the axis between the rotation shaft and the plurality of magnets;
Including, brushless motor. The brushless motor according to claim 1, wherein the plurality of granular elastic bodies have different dimensions and shapes. 3. The brushless motor according to claim 1, wherein the rotating body includes a first rotor core positioned annularly along the axis between the elastic body layer and the plurality of magnets. 4. 4. The rotating body according to claim 1, wherein the rotating body includes a second rotor core positioned annularly along the axis between the elastic layer and the rotating shaft. 5. Brushless motor. The brushless motor according to any one of claims 1 to 4, wherein the rotating body includes a resin portion that fixes at least the plurality of magnets, the elastic body layer, and the first rotor core. .

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