Electric motor and blowing device

Abstract

In this electric motor, a housing has a frame and a bracket. The frame and the bracket cover a rotor and a stator from opposite sides in the axial direction of a rotating shaft. A frame facing surface facing the stator in the axial direction of the rotating shaft is formed on the frame. A bracket facing surface facing the stator in the axial direction of the rotating shaft is formed on the bracket. A bracket-side iron core non-contact distance, which is the distance between an end part of the stator core on the bracket facing surface side and the bracket facing surface, is greater than a frame-side iron core non-contact distance, which is the distance between an end part of the stator core on the frame facing surface side and the frame facing surface.

Description

Electric motor and blower

[0001] The present disclosure relates to an electric motor and a blower device.

[0002] Patent Document 1 discloses an induction motor in which multiple conductor bars protrude like blades from the end faces of the end rings of the rotor. The rotor and stator are housed in an outer shell. When the rotor rotates, the multiple conductor bars agitate the air inside the outer shell, thereby suppressing a temperature rise in the stator.

[0003] Japanese Patent Application Laid-Open No. 2000-60045

[0004] However, in the conventional induction motor disclosed in Patent Document 1, heat is easily transferred from the rotor and stator to the entire outer shell, causing the temperature of the entire outer shell to rise. As a result, for example, if an electronic device is adjacent to a portion of the outer shell of the induction motor, the heat from the outer shell will raise the temperature of the electronic device, resulting in problems such as reduced performance and a shortened lifespan of the electronic device. Furthermore, for example, when pulling an electric cable around a device equipped with an induction motor, if the electric cable comes into contact with a portion of the induction motor exposed from the device, the electric cable may be damaged by the heat from the outer shell of the induction motor. Thus, conventional induction motors are susceptible to problems due to the inability to partially suppress temperature rise in the outer shell.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide an electric motor and a blower device that can more reliably suppress temperature rise in parts of the housing where temperature rise needs to be suppressed.

[0006] The electric motor according to the present disclosure includes a housing, a rotating shaft rotatably supported by the housing, a rotor rotatable relative to the housing integrally with the rotating shaft, and a cylindrical stator fixed to the housing and surrounding the outer circumferential surface of the rotor, the rotor and the stator being accommodated inside the housing, the housing having a frame and a bracket covering the rotor and the stator from opposite sides relative to the rotor and the stator in the axial direction of the rotating shaft, the rotating shaft penetrating the frame from inside the housing to outside the housing, and the stator having a cylindrical stator core and a stator iron core. The stator core has a stator winding provided in the core, the outer peripheral surface of which is in contact with the inner peripheral surfaces of the frame and the bracket, the frame has a frame facing surface which faces the stator in the axial direction of the rotating shaft, and the bracket has a bracket facing surface which faces the stator in the axial direction of the rotating shaft, and the bracket side core non-contact distance, which is the distance between the end of the stator core on the bracket facing surface side and the bracket facing surface, is greater than the frame side core non-contact distance, which is the distance between the end of the stator core on the frame facing surface side and the frame facing surface.Further, an electric motor according to the present disclosure includes a housing, a rotating shaft rotatably supported by the housing, a rotor rotatable relative to the housing integrally with the rotating shaft, and a cylindrical stator fixed to the housing and surrounding the outer circumferential surface of the rotor, the rotor and the stator being accommodated inside the housing, the housing having a frame and a bracket covering the rotor and the stator from opposite sides relative to the rotor and stator in the axial direction of the rotating shaft, the rotating shaft penetrating the frame from inside the housing to outside the housing, and the stator having a cylindrical stator core and a fixed The stator core has a stator winding provided on a stator core, the outer surface of which is in contact with the inner surfaces of the frame and the bracket, the frame has a frame facing surface which faces the stator in the axial direction of the rotating shaft, and the bracket has a bracket facing surface which faces the stator in the axial direction of the rotating shaft, and the frame side core non-contact distance, which is the distance between the end of the stator core on the frame facing surface side and the frame facing surface, is greater than the bracket side core non-contact distance, which is the distance between the end of the stator core on the bracket facing surface side and the bracket facing surface.

[0007] According to the present disclosure, it is possible to more reliably suppress a temperature rise in a portion of the housing where it is desired to suppress a temperature rise.

[0008] Fig. 1 is a cross-sectional view showing an electric motor according to a first embodiment. Fig. 2 is a cross-sectional view showing a blower having the electric motor of Fig. 2. Fig. 3 is a cross-sectional view showing an electric motor according to a second embodiment. Fig. 4 is a cross-sectional view showing a blower having the electric motor of Fig. 5. Fig. 5 is a cross-sectional view showing an electric motor according to a third embodiment. Fig. 6 is a cross-sectional view showing an electric motor according to a fourth embodiment.

[0009] The following describes embodiments of the subject matter of the present disclosure with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant explanations are appropriately simplified or omitted. Note that the subject matter of the present disclosure is not limited to the following embodiments, and any component of the embodiments may be modified or omitted within the scope of the gist of the present disclosure.

[0010] 1 is a cross-sectional view showing an electric motor according to embodiment 1. In the figure, electric motor 1 has a housing 2, a rotating shaft 3, a rotor 4, a stator 5, and a terminal block 6.

[0011] The rotating shaft 3 passes through the rotor 4. The rotor 4 is disposed coaxially with the rotating shaft 3. The rotor 4 is fixed to the rotating shaft 3.

[0012] The rotor 4 has a rotor core 41 and a secondary conductor (not shown). The rotor core 41 is cylindrical. The rotor core 41 is configured by laminating a plurality of electromagnetic steel plates in the axial direction of the rotating shaft 3. The secondary conductor is provided in the rotor core 41.

[0013] The stator 5 has a cylindrical shape. The stator 5 surrounds the outer peripheral surface of the rotor 4. As a result, the stator 5 faces the outer peripheral surface of the rotor 4 with a gap therebetween. The stator 5 is fixed to the housing 2. The stator 5 is disposed coaxially with the rotating shaft 3.

[0014] The stator 5 has a stator core 51 and a stator winding 52. The stator core 51 is cylindrical in shape. The stator core 51 is formed by stacking a plurality of electromagnetic steel plates in the axial direction of the rotating shaft 3. The inner peripheral surface of the stator core 51 faces the outer peripheral surface of the rotor core 41 via a gap. The stator core 51 is disposed relative to the housing 2 at the same position as the rotor core 41 in the axial direction of the rotating shaft 3. The dimensions of the stator core 51 in the axial direction of the rotating shaft 3 are the same as the dimensions of the rotor core 41 in the axial direction of the rotating shaft 3.

[0015] The stator winding 52 is provided on the stator core 51. In this embodiment, the winding method of the stator winding 52 is concentrated winding. However, the winding method of the stator winding 52 may also be distributed winding. The stator winding 52 is arranged in a plurality of slots provided in the stator core 51 at intervals in the circumferential direction of the stator core 51. Furthermore, parts of the stator winding 52 protrude as coil ends 52 a from both ends of the stator core 51 in the axial direction of the rotating shaft 3.

[0016] The rotor 4 and the stator 5 are housed inside the housing 2. The rotating shaft 3 is rotatably supported by the housing 2. This allows the rotor 4 to rotate integrally with the rotating shaft 3 relative to the housing 2 around the axis of the rotating shaft 3.

[0017] The housing 2 has a frame 21 and a bracket 22. The frame 21 and the bracket 22 cover the rotor 4 and the stator 5 from opposite sides of the rotor 4 and the stator 5 in the axial direction of the rotating shaft 3. The frame 21 and the bracket 22 are joined to each other while facing each other in the axial direction of the rotating shaft 3. In this embodiment, the shape and size of the frame 21 are the same as the shape and size of the bracket 22. In this embodiment, the frame 21 and the bracket 22 are molded using the same mold.

[0018] The frame 21 has a frame cylindrical portion 211 , a frame end wall portion 212 , a frame bearing receiving portion 213 , and a frame flange portion 214 .

[0019] The frame tubular portion 211 has a cylindrical shape. The axis of the frame tubular portion 211 coincides with the axis of the rotating shaft 3. Of both end portions of the frame tubular portion 211 in the axial direction of the rotating shaft 3, a frame end wall portion 212 is provided at one end and a frame flange portion 214 is provided at the other end. The frame end wall portion 212 closes the opening of the frame tubular portion 211. The frame flange portion 214 protrudes from the frame tubular portion 211 radially outward.

[0020] A frame through-hole 215 is provided in the center of the frame end wall portion 212. The rotating shaft 3 passes through the frame through-hole 215. As a result, the rotating shaft 3 passes through the frame 21 from inside the housing 2 and protrudes to the outside of the housing 2.

[0021] The frame bearing receiving portion 213 is a cylindrical protrusion provided on the frame end wall portion 212 surrounding the frame through-hole 215. The frame bearing receiving portion 213 protrudes from the frame end wall portion 212 into the interior of the housing 2.

[0022] A bearing through which the rotating shaft 3 passes is accommodated in the frame bearing accommodation portion 213 as a frame-side bearing 216. The outer peripheral surface of the frame-side bearing 216 fits into the inner peripheral surface of the frame bearing accommodation portion 213. The rotating shaft 3 is press-fitted into the frame-side bearing 216. As a result, the rotating shaft 3 is rotatably supported by the frame 21 via the frame-side bearing 216.

[0023] The bracket 22 has a bracket tubular portion 221 , a bracket end wall portion 222 , a bracket bearing accommodating portion 223 , and a bracket flange portion 224 .

[0024] The bracket tubular portion 221 has a cylindrical shape. The axis of the bracket tubular portion 221 coincides with the axis of the rotating shaft 3. Of both end portions of the bracket tubular portion 221 in the axial direction of the rotating shaft 3, a bracket end wall portion 222 is provided at one end portion, and a bracket flange portion 224 is provided at the other end portion. The bracket end wall portion 222 closes the opening portion of the bracket tubular portion 221. The bracket flange portion 224 protrudes from the bracket tubular portion 221 radially outward.

[0025] A bracket through-hole 225 is provided in the center of the bracket end wall portion 222. The rotating shaft 3 does not pass through the bracket through-hole 225. As a result, of both end portions of the rotating shaft 3, the end portion on the bracket 22 side is located inside the housing 2.

[0026] The bracket bearing receiving portion 223 is a cylindrical protrusion provided on the bracket end wall portion 222 to surround the bracket through-hole 225. The bracket bearing receiving portion 223 protrudes from the bracket end wall portion 222 into the housing 2.

[0027] A bearing through which the rotating shaft 3 passes is accommodated in the bracket bearing accommodating portion 223 as a bracket-side bearing 226. The outer peripheral surface of the bracket-side bearing 226 fits into the inner peripheral surface of the bracket bearing accommodating portion 223. The rotating shaft 3 is press-fitted into the bracket-side bearing 226. As a result, the rotating shaft 3 is rotatably supported by the bracket 22 via the bracket-side bearing 226.

[0028] The frame 21 and the bracket 22 are arranged so that the frame flange portion 214 and the bracket flange portion 224 face each other. The frame 21 and the bracket 22 are joined to each other by fastening the frame flange portion 214 and the bracket flange portion 224 with a plurality of fasteners 23.

[0029] The stator 5 is fixed inside the housing 2, spanning the frame 21 and the bracket 22. As a result, a portion of the outer peripheral surface of the stator core 51 is press-fitted into the inner peripheral surface of the frame cylindrical portion 211, and the remaining portion is press-fitted into the inner peripheral surface of the bracket cylindrical portion 221. Therefore, the outer peripheral surface of the stator core 51 is in contact with the inner peripheral surfaces of the frame 21 and the bracket 22.

[0030] An annular frame facing surface 21a is formed on a frame end wall portion 212 of the frame 21, facing the stator 5 in the axial direction of the rotating shaft 3. An annular bracket facing surface 22a is formed on a bracket end wall portion 222 of the bracket 22, facing the stator 5 in the axial direction of the rotating shaft 3.

[0031] The terminal block 6 is supported by the stator 5. The terminal block 6 is disposed between the stator winding 52 and the bracket facing surface 22 a. Therefore, the terminal block 6 is disposed between the bracket facing surface 22 a and the coil ends 52 a that protrude from the stator core 51 toward the bracket facing surface 22 a.

[0032] The terminal block 6 is made of an electrically insulating material, and in this embodiment, the terminal block 6 is made of resin.

[0033] Lead wires (not shown) extending from the stator winding 52 and power supply lead wires (not shown) are arranged on the terminal block 6. The lead wires of the stator winding 52 are electrically connected to the power supply lead wires at the terminal block 6. This allows power to be supplied to the stator winding 52.

[0034] In this embodiment, the electric motor 1 is an induction motor. The stator 5 generates a rotating magnetic field when an AC current is supplied to the stator winding 52 from the power supply lead wire. An induced current is generated in the secondary conductor of the rotor 4 by the rotating magnetic field generated by the stator 5. As a result, the rotor 4 rotates integrally with the rotating shaft 3 relative to the housing 2. At this time, heat is generated in both the rotor 4 and the stator 5.

[0035] Heat generated in the stator 5 moves from the outer peripheral surface of the stator core 51 to the frame 21 and the bracket 22. The heat generated in the stator 5 also moves to the frame 21 from the coil ends 52a of the stator winding 52 through the space inside the frame 21. Furthermore, the heat generated in the stator 5 moves from the stator 5 to the terminal block 6, and then from the terminal block 6 to the bracket 22 through the space inside the bracket 22.

[0036] The heat generated in the rotor 4 is transferred from the rotor 4 to the frame 21 via the rotating shaft 3 and the frame-side bearing 216. The heat generated in the rotor 4 is also transferred from the rotor 4 to the frame 21 by passing through the space inside the frame 21.

[0037] The heat generated in the rotor 4 is transferred from the rotor 4 to the bracket 22 via the rotating shaft 3 and the bracket-side bearing 226. The heat generated in the rotor 4 is also transferred from the rotor 4 to the bracket 22 by passing through the space inside the bracket 22.

[0038] Fig. 2 is a cross-sectional view schematically showing the electric motor 1 of Fig. 1. The dimension of the frame 21 in the axial direction of the rotating shaft 3 is defined as a frame axial dimension d1, and the dimension of the bracket 22 in the axial direction of the rotating shaft 3 is defined as a bracket axial dimension d2.

[0039] The distance between the end of the stator core 51 on the frame opposing surface 21a side and the frame opposing surface 21a is defined as a frame-side core non-contact distance d11. The dimension of the stator core 51 that contacts the inner peripheral surface of the frame 21 in the axial direction of the rotating shaft 3 is defined as a frame-side core contact dimension d12. The distance between the end of the stator winding 52 on the frame opposing surface 21a side and the frame opposing surface 21a is defined as a frame-side stator distance d13.

[0040] The distance between the end of the stator core 51 on the bracket opposing surface 22a side and the bracket opposing surface 22a is defined as a bracket-side core non-contact distance d21. Furthermore, the dimension of the stator core 51 that contacts the inner peripheral surface of the bracket 22 in the axial direction of the rotating shaft 3 is defined as a bracket-side core contact dimension d22. The distance between the end of the terminal block 6 on the bracket opposing surface 22a side and the bracket opposing surface 22a is defined as a bracket-side terminal block distance d23.

[0041] In this case, the frame axial dimension d1 is equal to the sum of the frame side core non-contact distance d11, the frame side core contact dimension d12, and the thickness of the frame end wall portion 212. The bracket axial dimension d2 is equal to the sum of the bracket side core non-contact distance d21, the bracket side core contact dimension d22, and the thickness of the bracket end wall portion 222. In this embodiment, the frame axial dimension d1 and the bracket axial dimension d2 are equal to each other.

[0042] The frame-side iron core non-contact distance d11 and the bracket-side iron core non-contact distance d21 are different in size. In this embodiment, the bracket-side iron core non-contact distance d21 is larger than the frame-side iron core non-contact distance d11. As a result, the dimension of the non-contact portion of the bracket 22 relative to the stator core 51 is larger than the dimension of the non-contact portion of the frame 21 relative to the stator core 51. Therefore, when heat transfers from the stator core 51 to the frame 21 and the bracket 22, the range in which the heat diffuses is wider in the bracket 22 than in the frame 21.

[0043] In this embodiment, the bracket-side core contact dimension d22 is smaller than the frame-side core contact dimension d12, so that the amount of heat transferred from the stator core 51 to the bracket 22 is less than the amount of heat transferred from the stator core 51 to the frame 21.

[0044] Furthermore, in this embodiment, the bracket-side terminal block distance d23 is greater than the frame-side stator distance d13, so that the amount of heat transferred from the terminal block 6 to the bracket 22 via the space inside the bracket 22 is less than the amount of heat transferred from the stator winding 52 to the frame 21 via the space inside the frame 21.

[0045] The position of the stator core 51 relative to the housing 2 is the same as the position of the rotor core 41 relative to the housing 2 in the axial direction of the rotating shaft 3. Therefore, the distance between the end of the rotor core 41 on the bracket facing surface 22a side and the bracket facing surface 22a is greater than the distance between the end of the rotor core 41 on the frame facing surface 21a side and the frame facing surface 21a. As a result, in this embodiment, the amount of heat that moves from the rotor 4 to the bracket 22 is less than the amount of heat that moves from the rotor 4 to the frame 21.

[0046] For this reason, in this embodiment, the temperature rise of the bracket 22 is suppressed more than the temperature rise of the frame 21. The electric motor 1 is used in, for example, a blower.

[0047] Next, a description will be given of a blower having the electric motor 1. Fig. 3 is a cross-sectional view schematically showing a blower 100 having the electric motor 1 of Fig. 2. The blower 100 has the electric motor 1, a housing 200, and a fan 300.

[0048] The housing 200 is shaped like a rectangular parallelepiped. An intake port 201 is provided on the bottom surface of the housing 200. An exhaust port 202 is provided on the side surface of the housing 200. A scroll casing (not shown) is fixed inside the housing 200. Inside the housing 200, an air passage 203 extending from the intake port 201 to the exhaust port 202 is formed by the scroll casing. An insertion hole 204 is provided on the top surface of the housing 200.

[0049] The housing 200 is inserted into an opening formed in a ceiling board inside a room (not shown). The housing 200 is attached to the ceiling board with the air intake 201 facing downward. As a result, the air intake 201 is exposed to the room, and the air exhaust 202 and the insertion hole 204 are located above the ceiling board in the attic. A duct (not shown) is connected to the air exhaust 202 in the attic. In this embodiment, the duct connected to the air exhaust 202 reaches outdoors.

[0050] The frame 21 is inserted through the insertion hole 204. The frame flange portion 214 and the bracket flange portion 224 overlap the upper surface of the housing 200. The frame flange portion 214 and the bracket flange portion 224 are fixed to the housing 200 by fasteners (not shown). As a result, the electric motor 1 is mounted in the housing 200 with the frame 21 inserted inside the housing 200 and the bracket 22 exposed to the outside of the housing 200. The end of the rotating shaft 3 protruding from the frame 21 is located inside the housing 200. When the housing 200 is attached to a ceiling panel, the bracket 22 is exposed from the housing 200 above the ceiling.

[0051] The fan 300 is provided inside the housing 200. In this embodiment, the fan 300 is arranged in an air passage 203 inside the housing 200. The fan 300 is fixed to the rotating shaft 3 of the electric motor 1. As a result, when power is supplied to the stator 5, the fan 300 rotates integrally with the rotating shaft 3 relative to the housing 2, centering on the axis of the rotating shaft 3. Therefore, the fan 300 rotates inside the housing 200 by the driving force of the electric motor 1.

[0052] A centrifugal fan, for example, is used as the fan 300. When the fan 300 rotates, air drawn into the fan 300 through the air intake 201 is blown out from the fan 300 in the centrifugal direction of the fan 300, generating an airflow that flows through the air passage 203. Therefore, the fan 300 rotates integrally with the rotating shaft 3 about the axis of the rotating shaft 3, thereby generating an airflow that flows through the air passage 203. The airflow generated by the rotation of the fan 300 passes through the air intake 201 from the outside of the housing 200, enters the air passage 203, and then passes through the air passage 203 and the air exhaust 202 to the outside of the housing 200. The airflow that has exited the housing 200 flows through a duct and is discharged to the outdoors. In this embodiment, the blower device 100 is used as a ventilation fan that draws in indoor air through the air intake 201 and discharges the drawn air to the outdoors. In addition, when the duct connected to the exhaust port 202 reaches the room rather than the outdoors, the blower device 100 is used as an indoor air circulation device that draws in indoor air through the intake port 201 and returns the drawn air to the room from a location other than the intake port 201.

[0053] When the air blower 100 is attached to a ceiling board in a room, the attic space is used as a work space around the air blower 100. For example, maintenance work on electrical equipment installed around the air blower 100 is performed in the attic space.

[0054] Because the bracket 22 is exposed from the housing 200 above the ceiling, for example, when an electric cable is pulled into the ceiling during maintenance work on electrical equipment, the insulation of the electric cable may come into contact with the bracket 22. If the temperature of the bracket 22 rises at this time, there is a risk that the heat from the bracket 22 may damage the insulation of the electric cable. Therefore, there are cases where it is desirable to suppress the temperature rise of the bracket 22 rather than the temperature rise of the frame 21.

[0055] In this embodiment, the temperature rise of bracket 22 exposed from housing 200 is suppressed more than the temperature rise of frame 21. This reduces the possibility that the insulation of an electric cable will be damaged even if the electric cable comes into contact with bracket 22, for example, and reduces the workload of workers around blower device 100.

[0056] In this electric motor 1, the bracket-side core non-contact distance d21 is greater than the frame-side core non-contact distance d11. Therefore, when heat transfers from the stator core 51 to the frame 21 and the bracket 22, the heat can be diffused over a wider area in the bracket 22 than in the frame 21. As a result, when it is desired to suppress a temperature rise in the bracket 22 in the housing 2, for example, when there is a risk that the sheath of an electric cable may come into contact with the bracket 22, the temperature rise in the bracket 22 can be suppressed more reliably than the temperature rise in the frame 21.

[0057] Furthermore, the bracket-side terminal block distance d23 is greater than the frame-side stator distance d13. This allows the amount of heat transferred from the terminal block 6 to the bracket 22 to be less than the amount of heat transferred from the stator winding 52 to the frame 21. As a result, when it is desired to suppress a temperature rise in the bracket 22 in the housing 2, the temperature rise in the bracket 22 can be suppressed more reliably than the temperature rise in the frame 21.

[0058] Furthermore, the frame axial dimension d1 and the bracket axial dimension d2 are the same. Therefore, by adjusting the press-fit amount of the stator core 51 into the frame 21 and the bracket 22, it is possible to easily adjust the bracket-side core non-contact distance d21 and the frame-side core non-contact distance d11. Furthermore, if the frame 21 and the bracket 22 have the same shape and size, the frame 21 and the bracket 22 can be molded using the same mold. This facilitates the manufacture of the electric motor 1 and also reduces the manufacturing cost of the electric motor 1.

[0059] Furthermore, in the blower device 100, the electric motor 1 is mounted in the housing 200 with the frame 21 disposed inside the housing 200 and the bracket 22 exposed to the outside of the housing 200. Therefore, when it is desired to suppress a temperature rise in the bracket 22 in the housing 2, for example, when there is a risk that the sheath of an electric cable may come into contact with the bracket 22, it is possible to more reliably suppress a temperature rise in the bracket 22 than a temperature rise in the frame 21.

[0060] In the first embodiment, the bracket-side terminal block distance d23 is greater than the frame-side stator distance d13. However, this is not limiting, and the bracket-side terminal block distance d23 may be smaller than the frame-side stator distance d13, or the bracket-side terminal block distance d23 and the frame-side stator distance d13 may be the same. Even in this case, since the bracket-side iron core non-contact distance d21 is greater than the frame-side iron core non-contact distance d11, it is possible to more reliably suppress a temperature rise in the bracket 22 than a temperature rise in the frame 21.

[0061] Embodiment 2. Figure 4 is a cross-sectional view showing an electric motor according to embodiment 2. Figure 5 is a cross-sectional view schematically showing the electric motor of Figure 4. In this embodiment, the frame-side core non-contact distance d11 is greater than the bracket-side core non-contact distance d21. As a result, the dimension of the non-contact portion of the frame 21 relative to the stator core 51 is greater than the dimension of the non-contact portion of the bracket 22 relative to the stator core 51. Therefore, when heat transfers from the stator core 51 to the frame 21 and the bracket 22, the range in which the heat diffuses is wider in the frame 21 than in the bracket 22.

[0062] In this embodiment, the frame-side core contact dimension d12 is smaller than the bracket-side core contact dimension d22, so that the amount of heat transferred from the stator core 51 to the frame 21 is less than the amount of heat transferred from the stator core 51 to the bracket 22.

[0063] Furthermore, in this embodiment, the frame-side stator distance d13 is greater than the bracket-side terminal block distance d23, so that the amount of heat transferred from the stator winding 52 to the frame 21 via the space inside the frame 21 is less than the amount of heat transferred from the terminal block 6 to the bracket 22 via the space inside the bracket 22.

[0064] The position of the stator core 51 relative to the housing 2 is the same as the position of the rotor core 41 relative to the housing 2 in the axial direction of the rotating shaft 3. Therefore, the distance between the end of the rotor core 41 on the frame facing surface 21a side and the frame facing surface 21a is greater than the distance between the end of the rotor core 41 on the bracket facing surface 22a side and the bracket facing surface 22a. As a result, in this embodiment, the amount of heat that moves from the rotor 4 to the frame 21 is less than the amount of heat that moves from the rotor 4 to the bracket 22.

[0065] For this reason, in this embodiment, the temperature rise of the frame 21 is suppressed more than the temperature rise of the bracket 22. Other configurations of the electric motor 1 are the same as those of the first embodiment. The electric motor 1 is used in, for example, a blower.

[0066] Next, a blower device having the electric motor 1 will be described. Fig. 6 is a cross-sectional view that schematically shows a blower device 100 having the electric motor 1 of Fig. 5. The blower device 100 in this embodiment has the electric motor 1, a housing 200, a fan 300, and an electronic device 400. The configuration of the electric motor 1 is the same as that of the electric motor 1 of Fig. 5. The configurations of the housing 200 and the fan 300 are the same as those in the first embodiment.

[0067] The electric motor 1 is provided in the housing 200 with the frame 21 disposed inside the housing 200 and the bracket 22 exposed to the outside of the housing 200. The electronic device 400 is provided inside the housing 200. In this embodiment, the electronic device 400 is attached inside the housing 200 to a top plate that forms the upper surface of the housing 200. As a result, in this embodiment, the electronic device 400 is adjacent to the frame 21. The electronic device 400 is a control device that controls the electric motor 1.

[0068] Here, when the temperature of frame 21 inside housing 200 rises, heat is transferred from frame 21 to electronic device 400 via the space inside housing 200. This causes the temperature of electronic device 400 to rise. In blower device 100, the higher the temperature of frame 21, the more likely it is that the performance of electronic device 400 will deteriorate or the lifespan of electronic device 400 will be shortened. Therefore, in blower device 100, there are cases where it is desirable to suppress the temperature rise of frame 21 in order to suppress the temperature rise of electronic device 400.

[0069] In this embodiment, the temperature rise of the frame 21 arranged inside the housing 200 is suppressed more than the temperature rise of the bracket 22. This suppresses the occurrence of problems such as a decrease in the performance of the electronic device 400 and a shortened lifespan of the electronic device 400. Furthermore, because the temperature rise of the electronic device 400 is suppressed, it becomes possible to install electronic device 400 incorporating circuits with even higher processing capabilities inside the housing 200. This also improves the processing capability of the electronic device 400.

[0070] In this electric motor 1, the frame-side core non-contact distance d11 is greater than the bracket-side core non-contact distance d21. Therefore, when heat transfers from the stator core 51 to the frame 21 and the bracket 22, the range over which the heat diffuses can be made wider in the frame 21 than in the bracket 22. As a result, when it is desired to suppress a temperature rise in the frame 21 in the housing 2, such as when the electronic device 400 is adjacent to the frame 21 inside the casing 200, the temperature rise in the frame 21 can be more reliably suppressed than the temperature rise in the bracket 22.

[0071] Furthermore, the frame-side stator distance d13 is greater than the bracket-side terminal block distance d23. This allows the amount of heat transferred from the stator winding 52 to the frame 21 to be less than the amount of heat transferred from the terminal block 6 to the bracket 22. As a result, when it is desired to suppress a temperature rise in the frame 21 of the housing 2, the temperature rise in the frame 21 can be suppressed more reliably than the temperature rise in the bracket 22.

[0072] Furthermore, in the blower device 100, the electronic device 400 is provided inside the housing 200. Therefore, when it is desired to suppress a temperature rise in the frame 21 in the housing 2, such as when the electronic device 400 is adjacent to the frame 21 inside the housing 200, it is possible to more reliably suppress a temperature rise in the frame 21 than a temperature rise in the bracket 22.

[0073] In the second embodiment, the frame-side stator distance d13 is greater than the bracket-side terminal block distance d23. However, this is not limiting, and the frame-side stator distance d13 may be smaller than the bracket-side terminal block distance d23, or the frame-side stator distance d13 and the bracket-side terminal block distance d23 may be the same. Even in this case, since the frame-side iron core non-contact distance d11 is greater than the bracket-side iron core non-contact distance d21, it is possible to more reliably suppress a temperature rise in the frame 21 than a temperature rise in the bracket 22.

[0074] Embodiment 3. Figure 7 is a cross-sectional view showing an electric motor according to embodiment 3. In this embodiment, the rotating shaft 3 has a specific shaft portion 31. The portion of the rotating shaft 3 other than the specific shaft portion 31 constitutes a shaft main body 32. The outer diameter of the specific shaft portion 31 is smaller than the outer diameter of the shaft main body 32. As a result, the cross-sectional area of ​​the specific shaft portion 31 in a plane perpendicular to the axial direction of the rotating shaft 3 is smaller than the cross-sectional area of ​​the shaft main body 32 in a plane perpendicular to the axial direction of the rotating shaft 3.

[0075] The specific shaft portion 31 is located between the rotor 4 and the bracket-side bearing 226. At the boundary between the specific shaft portion 31 and the shaft main body portion 32, an annular step portion 33 is formed along the circumferential direction of the rotating shaft 3.

[0076] At the position of the step portion 33, it is desirable that the outer diameter of the specific shaft portion 31 be equal to or less than half the outer diameter of the shaft body portion 32. Therefore, it is desirable that the cross-sectional area of ​​the specific shaft portion 31 be equal to or less than one-quarter of the cross-sectional area of ​​the shaft body portion 32 at the position of the step portion 33. It is desirable that the length of the specific shaft portion 31 in the axial direction of the rotating shaft 3 be equal to or more than one-half the spatial distance between the rotor 4 and the bracket-side bearing 226 in the axial direction of the rotating shaft 3. The other configurations of the electric motor 1 are the same as those in the first embodiment. That is, in this embodiment, a rotating shaft 3 having a specific shaft portion 31 is applied to the electric motor 1 according to the first embodiment.

[0077] In the present embodiment, the cross-sectional area of ​​specific shaft portion 31 is smaller than the cross-sectional area of ​​shaft main body portion 32, and therefore the magnitude of the thermal resistance in specific shaft portion 31 is greater than the magnitude of the thermal resistance in shaft main body portion 32. As a result, in the present embodiment, the amount of heat that moves through rotating shaft 3 from rotor 4 to bracket-side bearing 226 is less than when rotating shaft 3 does not have specific shaft portion 31.

[0078] The electric motor 1 is used in a blower device. The configuration of the blower device according to this embodiment is similar to the configuration of the blower device 100 according to the first embodiment, except that the configuration of the electric motor 1 is the configuration shown in Fig. 7 .

[0079] In this electric motor 1, the bracket-side core non-contact distance d21 is greater than the frame-side core non-contact distance d11. The cross-sectional area of ​​the specific shaft portion 31 in a plane perpendicular to the axial direction of the rotating shaft 3 is smaller than the cross-sectional area of ​​the shaft main body portion 32 in a plane perpendicular to the axial direction of the rotating shaft 3. The specific shaft portion 31 is located between the rotor 4 and the bracket-side bearing 226. This achieves the same effects as in the first embodiment, and also makes the thermal resistance of the specific shaft portion 31 greater than the thermal resistance of the shaft main body portion 32. This reduces the amount of heat transferred through the rotating shaft 3 from the rotor 4 to the bracket-side bearing 226. Therefore, when suppressing a temperature rise in the bracket 22 in the housing 2, the temperature rise in the bracket 22 can be suppressed more reliably than the temperature rise in the frame 21. Furthermore, not only the temperature rise in the bracket 22 but also the temperature rise in the bracket-side bearing 226 can be suppressed. This extends the life of the bracket-side bearing 226 and therefore the life of the electric motor 1.

[0080] Also, in the case of a blower, when it is desired to suppress a temperature rise in the bracket 22 in the housing 2, for example, when there is a risk that the sheath of an electric cable may come into contact with the bracket 22, the temperature rise in the bracket 22 can be suppressed more reliably than the temperature rise in the frame 21. Furthermore, it is possible to suppress a temperature rise in the bracket-side bearing 226, thereby extending the life of the electric motor 1.

[0081] In the third embodiment, the specific shaft portion 31 is located between the rotor 4 and the bracket-side bearing 226. However, this is not limiting. The specific shaft portion 31 may be located between the rotor 4 and the frame-side bearing 216. This reduces the amount of heat that moves along the rotating shaft 3 from the rotor 4 to the frame-side bearing 216. This not only suppresses a temperature rise in the bracket 22, but also a temperature rise in the frame 21. It also suppresses a temperature rise in the frame-side bearing 216, thereby extending the life of the electric motor 1.

[0082] Furthermore, in the third embodiment, the specific shaft portion 31 may be located at a position between the rotor 4 and the frame-side bearing 216, and at a position between the rotor 4 and the bracket-side bearing 226. In this way, it is possible to reduce the amount of heat that moves along the rotating shaft 3 from the rotor 4 to the frame-side bearing 216 and the bracket-side bearing 226. This not only suppresses a temperature rise in the bracket 22, but also a temperature rise in the frame 21. It is also possible to suppress a temperature rise in each of the frame-side bearing 216 and the bracket-side bearing 226, thereby further extending the life of the electric motor 1.

[0083] Fourth Embodiment Figure 8 is a cross-sectional view showing an electric motor according to a fourth embodiment. In this embodiment, similar to the third embodiment, the rotating shaft 3 has a specific shaft portion 31. The portion of the rotating shaft 3 other than the specific shaft portion 31 constitutes a shaft main body 32. The outer diameter of the specific shaft portion 31 is smaller than the outer diameter of the shaft main body 32. As a result, the cross-sectional area of ​​the specific shaft portion 31 in a plane perpendicular to the axial direction of the rotating shaft 3 is smaller than the cross-sectional area of ​​the shaft main body 32 in a plane perpendicular to the axial direction of the rotating shaft 3.

[0084] The specific shaft portion 31 is located between the rotor 4 and the frame-side bearing 216. At the boundary between the specific shaft portion 31 and the shaft main body portion 32, an annular step portion 33 is formed along the circumferential direction of the rotating shaft 3.

[0085] At the position of the step portion 33, it is desirable that the outer diameter of the specific shaft portion 31 be equal to or less than half the outer diameter of the shaft body portion 32. Therefore, it is desirable that the cross-sectional area of ​​the specific shaft portion 31 be equal to or less than one-quarter of the cross-sectional area of ​​the shaft body portion 32 at the position of the step portion 33. It is desirable that the length of the specific shaft portion 31 in the axial direction of the rotating shaft 3 be equal to or more than one-half the spatial distance between the rotor 4 and the bracket-side bearing 226 in the axial direction of the rotating shaft 3. The other configurations of the electric motor 1 are the same as those in the second embodiment. That is, in this embodiment, a rotating shaft 3 having a specific shaft portion 31 is applied to the electric motor 1 according to the second embodiment.

[0086] Because the cross-sectional area of ​​the specific shaft portion 31 is smaller than the cross-sectional area of ​​the shaft main body portion 32, the magnitude of the thermal resistance in the specific shaft portion 31 is greater than the magnitude of the thermal resistance in the shaft main body portion 32. As a result, the amount of heat that moves through the rotating shaft 3 from the rotor 4 to the frame-side bearing 216 is less than if the rotating shaft 3 does not have the specific shaft portion 31.

[0087] The electric motor 1 is used in a blower device. The configuration of the blower device according to this embodiment is similar to the configuration of the blower device 100 according to the second embodiment, except that the configuration of the electric motor 1 is the configuration shown in Fig. 8 .

[0088] In this electric motor 1, the frame-side iron core non-contact distance d11 is greater than the bracket-side iron core non-contact distance d21. The cross-sectional area of ​​the specific shaft portion 31 in a plane perpendicular to the axial direction of the rotating shaft 3 is smaller than the cross-sectional area of ​​the shaft main body portion 32 in a plane perpendicular to the axial direction of the rotating shaft 3. The specific shaft portion 31 is located between the rotor 4 and the frame-side bearing 216. This achieves the same effects as in the second embodiment, and also makes the thermal resistance of the specific shaft portion 31 greater than the thermal resistance of the shaft main body portion 32. This reduces the amount of heat transferred from the rotor 4 to the frame-side bearing 216 through the rotating shaft 3. Therefore, when suppressing a temperature rise in the frame 21 of the housing 2, the temperature rise in the frame 21 can be suppressed more reliably than the temperature rise in the bracket 22. Furthermore, not only the temperature rise in the frame 21 but also the temperature rise in the frame-side bearing 216 can be suppressed. This extends the life of the frame-side bearing 216 and therefore the life of the electric motor 1.

[0089] Furthermore, in the case of the air blower, when it is desired to suppress a temperature rise in the frame 21 in the housing 2, such as when the electronic device 400 is adjacent to the frame 21, the temperature rise in the frame 21 can be suppressed more reliably than the temperature rise in the bracket 22. Furthermore, the temperature rise in the frame-side bearing 216 can also be suppressed, thereby extending the life of the electric motor 1.

[0090] In the fourth embodiment, the specific shaft portion 31 is located between the rotor 4 and the frame-side bearing 216. However, this is not limiting. The specific shaft portion 31 may be located between the rotor 4 and the bracket-side bearing 226. This reduces the amount of heat that moves along the rotating shaft 3 from the rotor 4 to the bracket-side bearing 226. This not only suppresses a temperature rise in the frame 21, but also a temperature rise in the bracket 22. It is also possible to suppress a temperature rise in the bracket-side bearing 226, thereby extending the life of the electric motor 1.

[0091] Furthermore, in the above-described fourth embodiment, the specific shaft portion 31 may be located at a position between the rotor 4 and the frame-side bearing 216, and at a position between the rotor 4 and the bracket-side bearing 226. In this way, it is possible to reduce the amount of heat that moves along the rotating shaft 3 from the rotor 4 to each of the frame-side bearing 216 and the bracket-side bearing 226. This makes it possible to suppress not only a rise in temperature of the frame 21, but also a rise in temperature of the bracket 22. It is also possible to suppress a rise in temperature of each of the frame-side bearing 216 and the bracket-side bearing 226, thereby further extending the life of the electric motor 1.

[0092] In each of the above-described embodiments, the frame axial direction dimension d1 and the bracket axial direction dimension d2 are the same. However, the bracket axial direction dimension d2 may be larger than the frame axial direction dimension d1, or the bracket axial direction dimension d2 may be smaller than the frame axial direction dimension d1.

[0093] In each of the above-described embodiments, the electric motor 1 is applied to a blower device, but the device to which the electric motor 1 is applied is not limited to a blower device.

[0094] The configurations described in the above embodiments are merely examples of the contents of the present disclosure. The embodiments can be combined with other known technologies. Part of the configuration of the embodiments can be omitted or modified without departing from the gist of the present disclosure.

[0095] 1 Electric motor, 2 Housing, 3 Rotating shaft, 4 Rotor, 5 Stator, 6 Terminal block, 21 Frame, 21a Frame opposing surface, 22 Bracket, 22a Bracket opposing surface, 31 Specific shaft portion, 32 Shaft main body portion, 51 Stator core, 52 Stator winding, 100 Blower, 200 Housing, 216 Frame side bearing, 226 Bracket side bearing, 300 Fan, 400 Electronic device, d1 Frame axial dimension, d2 Bracket axial dimension, d11 Frame side core non-contact distance, d13 Frame side stator distance, d21 Bracket side core non-contact distance, d23 Bracket side terminal block distance.

Claims

1. Housing and A rotating shaft rotatably supported in the aforementioned housing, A rotor that is rotatable with respect to the housing and integral with the aforementioned rotating shaft, A cylindrical stator fixed to the housing and surrounding the outer surface of the rotor, Equipped with, The rotor and the stator are housed inside the housing. The housing has a frame and brackets that cover the rotor and stator from opposite sides in the axial direction of the rotating shaft, The rotating shaft extends from inside the housing, through the frame, and protrudes to the outside of the housing. The stator comprises a cylindrical stator core and stator windings provided on the stator core. The outer circumferential surface of the stator core is in contact with the inner circumferential surfaces of the frame and the bracket, respectively. The frame has a frame-facing surface that faces the stator in the axial direction of the rotation axis, The bracket has a bracket-facing surface that faces the stator in the axial direction of the rotation shaft. The bracket-side core non-contact distance, which is the distance between the bracket-facing end of the stator core and the bracket-facing surface, is greater than the frame-side core non-contact distance, which is the distance between the frame-facing end of the stator core and the frame-facing surface. An electric motor in which the bracket-side core contact dimension, which is the dimension of the stator core that contacts the inner circumferential surface of the bracket in the axial direction of the rotating shaft, is smaller than the frame-side core contact dimension, which is the dimension of the stator core that contacts the inner circumferential surface of the frame in the axial direction of the rotating shaft.

2. The terminal block on which the lead wires of the stator winding are arranged is provided. A portion of the stator winding protrudes from both ends of the stator core in the axial direction of the rotating shaft, The terminal block is positioned between the bracket's opposing surface and the stator winding. The electric motor according to claim 1, wherein the bracket-side terminal block distance, which is the distance between the end of the terminal block on the bracket-facing surface side and the bracket-facing surface, is greater than the frame-side stator distance, which is the distance between the end of the stator winding on the frame-facing surface side and the frame-facing surface.

3. The rotating shaft is supported by the bracket via a bracket-side bearing and by the frame via a frame-side bearing. The aforementioned rotating shaft has a specific shaft portion, The portion of the rotating shaft other than the specified shaft portion is the shaft body portion. The cross-sectional area of ​​the specific shaft portion in a plane perpendicular to the axial direction of the rotation axis is 1 / 4 or less of the cross-sectional area of ​​the shaft body portion in a plane perpendicular to the axial direction of the rotation axis. The electric motor according to claim 2, wherein the specific shaft portion is located at least one of the following positions: between the rotor and the bracket-side bearing, and between the rotor and the frame-side bearing.

4. The electric motor according to claim 3, wherein the dimensions of the frame in the axial direction of the rotating shaft and the dimensions of the bracket in the axial direction of the rotating shaft are the same as each other.

5. The casing and The housing is provided with an electric motor according to any one of claims 1 to 4, A fan is provided inside the aforementioned housing and rotates by the driving force of the electric motor. Equipped with, The electric motor is a blower provided in the housing, with the frame positioned inside the housing and the bracket exposed outside the housing.

6. Housing and A rotating shaft rotatably supported in the aforementioned housing, A rotor that is rotatable with respect to the housing and integral with the aforementioned rotating shaft, A cylindrical stator fixed to the housing and surrounding the outer surface of the rotor, Equipped with, The rotor and the stator are housed inside the housing. The housing has a frame and brackets that cover the rotor and stator from opposite sides in the axial direction of the rotating shaft, The rotating shaft extends from inside the housing, through the frame, and protrudes to the outside of the housing. The stator comprises a cylindrical stator core and stator windings provided on the stator core. The outer circumferential surface of the stator core is in contact with the inner circumferential surfaces of the frame and the bracket, respectively. The frame has a frame-facing surface that faces the stator in the axial direction of the rotation axis, The bracket has a bracket-facing surface that faces the stator in the axial direction of the rotation shaft. The frame-side core non-contact distance, which is the distance between the end of the stator core on the frame-facing surface side and the frame-facing surface, is greater than the bracket-side core non-contact distance, which is the distance between the end of the stator core on the bracket-facing surface side and the bracket-facing surface. An electric motor in which the frame-side core contact dimension, which is the dimension of the stator core that contacts the inner circumferential surface of the frame in the axial direction of the rotating shaft, is smaller than the bracket-side core contact dimension, which is the dimension of the stator core that contacts the inner circumferential surface of the bracket in the axial direction of the rotating shaft.

7. A space exists between the stator and the frame facing surface, The electric motor according to claim 6, wherein a space exists between the stator and the bracket facing surface.

8. The terminal block on which the lead wires of the stator winding are arranged is provided. A portion of the stator winding protrudes from both ends of the stator core in the axial direction of the rotating shaft, The terminal block is positioned between the bracket's opposing surface and the stator winding. The electric motor according to claim 7, wherein the frame-side stator distance, which is the distance between the end of the stator winding on the frame-facing side and the frame-facing surface, is greater than the bracket-side terminal block distance, which is the distance between the end of the terminal block on the bracket-facing side and the bracket-facing surface.

9. The rotating shaft is supported by the bracket via a bracket-side bearing and also by the frame via a frame-side bearing. The aforementioned rotating shaft has a specific shaft portion, The portion of the rotating shaft other than the specified shaft portion is the shaft body portion. The cross-sectional area of ​​the specific shaft portion in a plane perpendicular to the axial direction of the rotation axis is 1 / 4 or less of the cross-sectional area of ​​the shaft body portion in a plane perpendicular to the axial direction of the rotation axis. The electric motor according to claim 8, wherein the specific shaft portion is located at least one of the following positions: between the rotor and the bracket-side bearing, and between the rotor and the frame-side bearing.

10. The electric motor according to claim 9, wherein the dimensions of the frame in the axial direction of the rotating shaft and the dimensions of the bracket in the axial direction of the rotating shaft are the same as each other.

11. The casing and The housing is provided with an electric motor according to any one of claims 6 to 10, A fan is provided inside the aforementioned housing and rotates by the driving force of the electric motor, The electronic equipment that controls the electric motor is provided on the top plate that forms the upper surface of the housing inside the housing. Equipped with, The electric motor is a blower provided on the top plate of the housing with the frame positioned inside the housing.