JP2024021192A - Outer rotor type motor - Google Patents

Abstract

The present invention provides an outer rotor type motor that can suppress excessive temperature rise. [Solution] In an outer rotor type motor in which a rotor 23 is rotatably provided on the radially outer side of a stator 24, the rotor 23 is driven independently of a rotating shaft 21 connected to the rotor 23, and the load on the rotating shaft 21 in the motor is The fan 71 is disposed on the rear end side opposite to the front end side to which the motor is connected, and the heat radiation fins 72 are formed on the rear end side of the motor. and a flow guide member 73 that guides the airflow generated by the fan 71 to the radiation fins 72, and is configured such that the airflow generated by the fan 71 passes through the radiation fins 72 formed on the rear end side of the motor. [Selection diagram] Figure 1

Description

The present invention relates to an outer rotor type motor that includes a rotor on the radially outer side of a stator.

Examples of the outer rotor type motor include the motor shown in Patent Document 1. This motor includes a motor section that generates power and a casing that covers the motor section. The casing has a cup shape with an opening formed at one end, and the opening of the casing is closed with a lid. The motor section includes a cylindrical bearing house that is fixed through a hole formed in the lid and rotatably supports a rotating shaft, and a cup-shaped rotor that is fixed to the rotating shaft so as to rotate together with the rotating shaft. and a stator fixed to the outside of the bearing house so as to face the inner surface of the peripheral wall of the rotor in the radial direction.

Incidentally, in manufacturing equipment that dislikes speed fluctuations and torque fluctuations, there is a demand for replacing the combination of the motor and deceleration means with a direct drive motor.

Japanese Patent Application Publication No. 1-243837

However, if a large torque is generated only by electromagnetic force, the direct drive motor itself becomes large. In order to prevent this, it is necessary to increase the electromagnetic force (current) to increase the electromagnetic force per area where electromagnetic force is generated, but since copper loss occurs in proportion to the square of the electromagnetic force (current). However, there was a disadvantage that the loss per motor surface area increased and the motor could not be thermally realized unless the cooling capacity was increased. In particular, in a motor whose motor portion is covered with a casing, the performance may further deteriorate.

Therefore, an object of the present invention is to provide an outer rotor type motor that can suppress excessive temperature rise.

The present invention provides an outer rotor type motor in which a rotor is rotatably provided on the outside of a stator in a radial direction, and is driven independently of a rotating shaft connected to the rotor, and the load of the rotating shaft in the motor is connected to the outer rotor type motor. a fan disposed on the rear end side opposite to the front end side of the motor; a heat radiation fin formed on the rear end side of the motor; a flow guide member that guides airflow to the heat radiation fins, and the airflow generated by the fan passes through the heat radiation fins formed on the rear end side of the motor.

According to the present invention, the airflow generated by the fan passes through the heat dissipation fins formed on the rear end side of the motor, thereby concentrating the cooling capacity on the rear end side of the motor and suppressing excessive temperature rise. It is also effective in cases where it would be undesirable for airflow to flow to the load side connected to the motor rotating shaft. Furthermore, since the fan is driven by external power independently of the rotating shaft connected to the rotor, the fan's rotation speed does not decrease even if the designed rotation speed of the rotor is low, improving cooling efficiency. It never declines.

Further, in the outer rotor type motor of the present invention, the fan is disposed at the center in the radial direction on the rear end surface of the motor, and the radiation fins are arranged so as to surround the fan in the circumferential direction on the rear end surface of the motor. may be placed.

As mentioned above, by configuring the configuration in which the airflow generated by the fan placed in the radial center of the rear end face of the motor passes through the radiating fins placed to surround the fan, the airflow before and after cooling is not confused. This allows for efficient airflow.

Further, in the outer rotor type motor of the present invention, a recess is formed in the radial center of the rear end surface of the motor, and the fan is an axial flow fan, and the airflow generated by the fan passes through the recess. Alternatively, the heat radiation may be configured to flow in a radial direction by the heat dissipation fins.

In the above configuration, by forming the concave portion, the vicinity of the inner diameter side surface of the stator, which is the main heat source, can be cooled, so that the cooling capacity is further improved. Furthermore, since the concave portion can increase the area in contact with the airflow generated by the fan, it is also possible to cool sensors, bearings, etc. provided in the motor. Furthermore, since a general-purpose axial fan that is easily available can be used, it is advantageous in terms of cost.

Further, the outer rotor type motor of the present invention has a plurality of heat sink members arranged in a circumferential direction on a rear end surface of the motor, which are separate from the motor, and each heat sink member has the heat radiation fins. However, the radially inner sides may be linear, and the plurality of heat sink members may be arranged adjacent to each other such that the ends of the radially inner sides touch each other.

As mentioned above, since the plurality of heat sink members arranged in the circumferential direction are adjacent to each other so that the ends of the radially inner sides touch each other, airflow is difficult to leak from between the heat sink members adjacent in the circumferential direction. Airflow can be effectively applied to the heat radiation fins.

Further, the outer rotor type motor of the present invention may include a housing that covers the stator and the rotor.

As described above, by providing the housing, the motor can be fixed on the load side via the housing. Moreover, since the rotating part is not exposed, it can be used safely.

According to the present invention, it is possible to provide an outer rotor type motor that can suppress excessive temperature rise by concentrating the cooling capacity on the rear end side of the motor even if the electromagnetic force (current) of the motor is increased. .

FIG. 1 is a longitudinal cross-sectional side view of an outer rotor type motor of the present invention. It is a side view of the same motor. It is an exploded perspective view of the same motor. FIG. 7 is a longitudinal side view showing another form of an outer rotor type motor.

An embodiment of an outer rotor type motor of the present invention will be described based on the drawings.

The outer rotor type motor of the present invention is configured as a direct drive motor (hereinafter simply referred to as a DD motor) that directly transmits generated power to an object without using a speed reduction mechanism. The DD motor 1 includes a housing 3 for housing a motor section 2 that generates power in a closed state, and is configured as a fully enclosed external fan type motor with a fan disposed outside the motor. Further, the DD motor 1 has an outer rotor type structure in which a rotor 23, which will be described later, is rotatably supported within the housing 3 on the radially outer side of a stator 24, which will be described later. In addition, in FIG. 1, the protruding side of the rotary shaft 21 that protrudes from the housing 3 and is connected to a load is referred to as the front side, and the side where the rotary shaft 21 does not protrude from the housing 3, that is, the side that is opposite to the front side to which the load is connected. In the following, the rear side will be described.

The housing 3 is made of a metal material, and as shown in FIGS. 1 and 2, has a cylindrical housing body 31 with both ends opened in the front and rear directions, a front lid body 32 that closes the front and rear openings of the housing body 31, and a rear lid body 32 that closes the front and rear openings of the housing body 31. A side lid body 33 is provided. The housing 3 is provided with a sensor (not shown) for detecting the rotational position of the rotor 23, which will be described later.

As shown in FIG. 1, the front lid body 32 includes a ring-shaped disk portion 321 that has an opening formed in the center in the radial direction and is locked and fixed to the front end portion of the housing body 31; It includes a cylindrical portion 322 that protrudes forward from the inner side portion, and an inner flange portion 323 that protrudes inward from the front end of the cylindrical portion 322. Inside the cylindrical portion 322, a first bearing 4 that rotatably supports a front side portion of a rotating shaft 21, which will be described later, is arranged. Further, the rear side portion of the rotating shaft 21, which will be described later, is rotatably supported by a second bearing 5 arranged inside a bearing house 22, which will be described later.

The rear lid body 33 includes a disk portion 331 having a circular outer shape and fixedly fixed to the rear end of the housing body 31, and a bearing that protrudes forward from the front end surface of the radially inner portion of the disk portion 331 to be described later. It includes a circular ring-shaped fitting part 332 that fits onto the rear end of the house 22. In addition, when the fitting part 332 is externally fitted to the rear end of the bearing house 22, which will be described later, the radial inner peripheral surface 331A of the disc part 331 of the rear lid 33 and the rear side of the bearing house 22, which will be described later. 221 is flush with the radial inner peripheral surface 221A.

The motor section 2 includes a cylindrical bearing house in which a rotating shaft 21 to which a load is connected to the tip (front end) and a second bearing 5 that rotatably supports the rear side of the rotating shaft 21 are arranged. 22, a cup-shaped rotor 23 connected to rotate integrally with the rotating shaft 21, and a stator 24 fixed in contact with the outer surface of the bearing house 22 so as to face the inner surface of the rotor 23 in the radial direction. It is equipped with. That is, the stator 24 is located on the radially inner side of the rotor 23.

The rotor 23 includes a disk-shaped front wall portion 231 connected to the rotating shaft 21, a cylindrical side wall portion 232 extending rearward from the radially outer end of the front wall portion 231, and a permanent wall portion provided on the side wall portion 232. A magnet (not shown).

The stator 24 includes a plurality of teeth around which coils are wound. Heat is generated in the stator 24 when the motor section 2 is driven. This heat is transmitted to the rear lid 33 and the bearing house lid 6, which will be described later, via the bearing house 22 that contacts the stator 24. In this way, the heat generated in the stator 24 is transmitted via the bearing house 22 to the rear lid 33 and the bearing house lid 6, which will be described later. By applying the airflow generated by the fan 71 to the radiation fins 72 formed on the rear end surface, the stator 24 can be efficiently cooled. Note that, as described above, since the stator 24 is located on the radially inner side of the rotor 23, cooling from a radially outer position of the housing 3 is less efficient than cooling from the axial end face. Further, since outer rotor type direct drive motors often have a flat shape in the axial direction, cooling from the radial direction cannot be expected because it is difficult to secure a cooling area.

The bearing house 22 has a cylindrical shape and includes a rear side part 221 that fits into the fitting part 332 of the rear lid 33 and a front side part 222 that extends forward from the rear side part 221. A first step portion 2211 that protrudes inward is formed at the front end of the rear side portion 221 , and a first step portion 2211 that protrudes further inward than the first step portion 2211 at the front end side of the first step portion 2211 is formed behind the second bearing 5 . A second stepped portion 2212 is formed to receive the end surface 5B.

A circular plate-shaped bearing house lid 6 for closing the opening of the bearing house 22 is fixedly fixed to the first stepped portion 2211 . The rear end surface 6B of the bearing house cover 6, the radial inner circumferential surface 221A of the rear side part 221 of the bearing house 22, and the radial inner circumferential surface 331A of the disc part 331 of the rear cover 33 form the housing. A recessed portion H recessed toward the front side is formed in the radial center of the rear end surface at No. 3. This recess H is formed by arranging the rotating shaft 21 such that the rear end of the rotating shaft 21 is located forward of the rear ends of the rotor 23 and the stator 24. The recess H is located behind the rotating shaft 21 and is used to guide an airflow generated by a cooling section 7, which will be described later, for cooling the DD motor 1, thereby eliminating the need for a special guide member. By forming the recess H in this manner, the vicinity of the inner diameter side surface of the stator 24 can be cooled, so that the cooling capacity is further improved. Further, since the recess H can increase the area in which the airflow generated by the fan 71 comes into contact, it is possible to cool down a sensor (not shown) with low heat resistance provided in the motor, the bearing 5, and the like.

Further, the DD motor 1 is equipped with a cooling section 7. As shown in FIGS. 1 and 2, the cooling unit 7 is arranged on the axial end face (rear end face) of the housing 3, and is independent of the rotating shaft 21 connected to the rotor 23 by external power (not shown). a fan 71 driven by the fan 71; a radiation fin 72 formed on the axial end face (rear end face) of the housing 3 at a position in contact with the airflow generated by the fan 71; A flow guide member 73 that guides the airflow generated by the fan 71 to the heat radiation fins 72 is provided. Therefore, the DD motor 1 is cooled by cooling the heat radiation fins 72 provided on the axial end surface (rear end surface) of the rear lid body 33 immediately behind the stator 24, which is the main heat source, by the airflow from the fan 71. Efficiency can be increased. Moreover, since the fan 71 is driven independently of the rotating shaft 21 connected to the rotor 23 by external power, the rotation speed of the fan 71 does not decrease even if the designed rotation speed of the rotor 23 is low. There is no reduction in cooling efficiency.

The fan 71 is arranged at the radial center of the axial end surface (rear end surface) of the housing 3. Further, the heat radiation fins 72 are disposed so as to surround the fan 71 in the circumferential direction on the axial end face (rear end face) of the housing 3 . As will be described later, a plurality of radiating fins 72 are provided on the bottom plate portion 741 in a radially long rectangular shape and spaced apart from each other in the circumferential direction in a substantially parallel posture. The fan 71 takes in air at the center in the radial direction, and the taken air passes through the radiation fins 72 and is exhausted in the radial direction and the direction along the radial direction. Therefore, air is taken in by the fan 71 at the center in the radial direction, and the taken air passes through the radiation fins 72 arranged so as to surround the fan 71 and is exhausted in the radial direction and the direction along the radial direction. , it is possible to prevent the airflow before and after cooling from becoming complicated, and it is possible to form an efficient airflow. In addition, the air taken in by the fan 71 passes through the radiation fins 72 arranged on the axial end surface (rear end surface) and is exhausted in the radial direction and the direction along the radial direction, so that the air is directed toward the rotating shaft 21. This is effective when it is not good if airflow flows to the connected load side.

Since the fan 71 in this embodiment is a general-purpose axial fan that is easily available, it is advantageous in terms of cost. As shown in FIG. 3, this axial flow fan includes an impeller 711 in which a plurality of blades 711a are provided on the outer periphery of a cup-shaped hub 711b, a motor (not shown) that rotates the impeller 711, and an impeller 711 that rotates the impeller 711. 711 and a casing 712 for housing the motor, and a power cord (not shown) for supplying external power (electric power) to the motor. The airflow generated by intake from the rear by the fan 71 flows radially outward after passing through the recess H, and is exhausted after passing through the radiation fins 72. In this embodiment, a fan 71 having a rectangular outer shape in plan view (axial view) is used, but a fan having a circular outer shape may also be used.

The casing 712 includes a cylindrical casing body 7121, four flange portions 7122 that bulge out in all directions at both ends of the casing body 7121 in the axial direction (vertical direction), and upper and lower flange portions 7122, 7122. and four cylindrical connecting portions 7123 that connect the. Each flange portion 7122 is formed with a through hole 7122a through which the screw B is inserted. Insert the screw B from the through hole 7122a of the flange portion 7122 on one end side through the connecting portion 7123 into the through hole 7122a of the flange portion 7122 on the other end side, and then insert the screw B into the radially outer portion of the bearing house lid 6 in the circumferential direction. The fan 71 is fixed to the rear end surface of the housing 3 via the threaded bodies 8 by screwing the tips of the screws B into four cylindrical threaded bodies 8 erected at intervals along the housing 3. .

The radiation fins 72 are provided in a heat sink member 74 that is separate from the housing 3 . Since the rectangular heat sink member 74 is versatile, it is advantageous in terms of cost. The heat sink member 74 is attached to the rear end surface 331B of the disk portion 331 of the rear lid 33, has a long dimension in the circumferential direction, and has a shape that directly faces the rear end surface of the DD motor 1 (in the axial direction A bottom plate part 741 having a rectangular shape (shape), and a plurality of radiating fins 72 that are rectangular in the radial direction and are erected in a substantially parallel attitude at intervals in the circumferential direction on the bottom plate part 741. A plurality of heat sink members 74 (six in FIG. 3) are arranged circumferentially on the rear end surface 331B of the disk portion 331 of the rear lid 33 so as to surround the fan 71. It is configured in a polygonal (hexagonal) shape. The heat sink member 74 is preferably made of a material with good thermal conductivity, such as aluminum metal. Each heat sink member 74 has a straight side arranged on the inside in the radial direction. Further, the plurality of heat sink members 74 arranged in the circumferential direction are adjacent to each other such that the inner peripheral side ends of the radiation fins 72A, 72A provided at the ends of the radially inner side are in contact with each other. By arranging them in this way, it is possible to eliminate the gap between the heat sink members 74, 74 adjacent to each other in the circumferential direction, so that the airflow is less likely to leak therefrom, and the airflow can be effectively applied to the radiation fins 72. Note that the outer peripheral side ends of the radiation fins 72A, 72A may be separated from each other.

As shown in FIG. 3, the flow guide member 73 is composed of a plate-shaped circular member, and has an outer diameter slightly smaller than the outer diameter of the rear lid 33. It may be made the same size as the outer diameter. A rectangular through hole 73K is formed in the radial center of the flow guide member 73, into which a part of the fan 71 can be inserted so as to be located on the front side of the flow guide member 73. The outer diameter of the fan 71 is configured to be slightly smaller than the inner diameter of the through hole 73K to prevent airflow generated by the fan 71 from leaking from the gap between the through hole 73K and the fan 71. Moreover, notches 73U are formed at two locations in the circumferential direction on the outer peripheral edge of the flow guide member 73, respectively. At a position on the rear end surface 331B of the disk portion 331 of the rear lid 33 corresponding to the notches 73U, 73U, a circular rod-shaped body 9 having a thread formed on its outer surface is erected. A screw member 10 is provided, which has a shaft portion 10A that is screwed into these rod-shaped bodies 9, respectively, and a head portion 10B that has a larger outer diameter than the notch 73U and abuts on the outer periphery of the notch 73U. By passing the shaft portion 10A of each screw member 10 through the notch 73U and then screwing it into the rod-shaped body 9, the lower surface of the head 10B of each screw member 10 comes into contact with the outer peripheral edge of the notch 73U and moves downward. Press. Thereby, the flow guiding member 73 can be fixed to the rod-shaped bodies 9, 9. When the flow guide member 73 is fixed to the rod-shaped bodies 9, 9, the front surface 73A of the flow guide member 73 and the rear end surface 73B (see FIG. 2) of the radiation fin 72 are in contact with each other, so that no gap is created between them. There is. Furthermore, through-holes for screw insertion are formed at four locations in the circumferential direction of the flow guide member 73, and screws are inserted inside at each position of the rear end surface 331B of the disc portion 331 corresponding to these through-holes. The formed screw member 12 is erected. Therefore, by inserting each of the four screws 11 into the through holes and then screwing them into the screw member 12, the flow guiding member 73 can be fixed with even four screws 11. The method of fixing the flow guiding member 73 may be other than the method shown in FIG. 3.

When the DD motor 1 and the fan 71 configured as described above are driven, the rotating shaft 21 is driven and rotated, and the impeller 711 of the fan 71 is rotated. The air sucked in from the rear end of the fan 71 by the rotation of the impeller 711 flows toward the front end (see arrow R1) as shown in FIG. (see arrow R2). The air guided in the radially outward direction R2 is guided by the radially inner circumferential surface 221A of the rear side portion 221 of the bearing house 22 and the radially inner circumferential surface 331A of the disc portion 331 of the rear lid body 33, and is guided backward. (See arrow R3). The air that has moved rearward hits the front surface 73A of the flow guide member 73 and is guided in a radially outward direction (see arrow R4). This guided air hits the radiation fins 72, thereby cooling the rear lid 33 to which the heat from the stator 24 is transmitted via the bearing house 22. Thereby, the cooling efficiency of the motor can be increased. Moreover, the air is also applied to the rear end surface 6B of the bearing house lid 6 that constitutes the recess H and the radially inner circumferential surface 221A of the rear side part 221 of the bearing house 22 (the part to which the heat of the stator 24 is transferred). By cooling those parts, the cooling efficiency of the motor can be further increased.

Note that the outer rotor type motor according to the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

In the embodiment described above, an outer rotor type direct drive motor is used, but the present invention is not limited to this.

Furthermore, in the embodiment described above, the heat sink member 74 is provided with the radiation fins 72 separately from the housing 3, but they may be formed integrally with the housing 3.

Further, in the embodiment described above, a plurality of heat sink members 74 are arranged in the circumferential direction, but the heat sink member may be configured in a single ring shape.

Further, in the embodiment, the rectangular heat sink member 74 is shown, but it may be an arcuate heat sink member.

Furthermore, in the embodiment described above, the fan 71 sucks air from the rear and discharges it in the radially outward direction. Air may be sucked and discharged to the rear of the motor.

Further, in the above embodiment, the recess H is formed in the radial center of the axial end face (rear end face) of the motor, but a flat axial end face (rear end face) without a recess may be used.

Furthermore, in the embodiment described above, the flow guiding member 73 is configured to have a size that forms an air flow path to a position radially outward from the outer peripheral edge of all the heat sink members 74. The flow guide member 73 may be configured to have a size that forms an air flow path only up to the outer peripheral edge, that is, in the range from the fan 71 to the radiation fins 72. Alternatively, the flow guiding member 73 may be large enough to cover the inner peripheral edges of all the heat sink members 74.

Further, in the embodiment, the motor axial end face (rear end face) is a plane perpendicular to the motor axial direction, but it is sufficient as long as it is not inclined outward from the motor central axis toward the load side.

Further, in the embodiment, a plurality of radiating fins 72 are arranged on the bottom plate part 741 in a radially long rectangular shape and spaced apart in the circumferential direction in a substantially parallel posture, but the shape is not limited to this, for example, It may be curved.

In short, as long as the airflow does not flow toward the load side, the airflow may flow in any direction.

Further, in the above embodiment, an axial fan is used as the fan, but a centrifugal fan, a mixed flow fan, or the like may be used.

Further, in the above embodiment, the DD motor 1 is shown in which the motor section 2 such as the stator 24 and the rotor 23 is covered with the housing 3, but as shown in FIG. There may be. Specifically, among the housing body 31, front side cover body 32, and rear side cover body 33 that constitute the housing 3, the housing body 31 and the front side cover body 32 are omitted, and the housing body 31 and the front side cover body 32 are provided on the opposite side to the rotation axis 21. A cooling section 7 is provided on the rear lid body 33. Note that, since the rear lid 33 is provided on the rear side of the motor unit 2 to attach the cooling unit 7, it can also be constructed from a dedicated mounting member having a shape different from that of the rear lid 33. . In FIG. 4, since the stepped portion of the rotating shaft 21 is formed at a position closer to the front side than in FIG. Same as 1.

DESCRIPTION OF SYMBOLS 1... Motor, 2... Motor part, 3... Housing, 4... First bearing, 4... First bearing, 5... Second bearing, 5B... Rear end surface, 6... Cover for bearing house, 6B... Rear end surface, 7 ...Cooling part, 8...Screw body, 9...Bar-shaped body, 10...Screw member, 10A...Shaft part, 10B...Head, 11...Screw, 12...Screw member, 21...Rotating shaft, 22...Bearing house, 23... Rotor, 24... Stator, 31... Housing body, 32... Front lid, 33... Rear lid, 71... Fan, 72, 72A... Radiation fin, 73... Direction member, 73A... Front, 73B... Rear end surface, 73K...Through hole, 73U...Notch, 74...Heat sink member, 221...Rear side part, 221A...Radially inner peripheral surface, 222...Front side part, 231...Front wall part, 232...Side wall part, 321...Disc part , 322... Cylindrical part, 323... Inner flange part, 331... Disc part, 331A... Radial inner peripheral surface, 331B... Rear end surface, 332... Fitting part, 711... Impeller, 711a... Vane, 711b... Hub, 712... Casing, 741... Bottom plate part, 2211... First step part, 2212... Second step part, 7121... Casing body, 7122... Flange part, 7122a... Through hole, 7123... Connecting part, B... Screw, H... Recessed part , R1-R4...arrow

Claims (5)

In an outer rotor type motor, in which the rotor is rotatably provided on the outside of the stator in the radial direction,
a fan that is driven independently of a rotating shaft connected to the rotor and is disposed on a rear end side of the motor opposite to a front end side to which a load of the rotating shaft is connected;
a radiation fin formed on the rear end side of the motor;
a flow guiding member that guides airflow generated by the fan to the radiation fins at least in a range from the fan to the radiation fins;
An outer rotor type motor, wherein airflow generated by the fan passes through the heat radiation fins formed on the rear end side of the motor. The fan is arranged at a radial center on a rear end surface of the motor,
The outer rotor type motor according to claim 1, wherein the heat dissipation fins are disposed on a rear end surface of the motor in a circumferential direction so as to surround the fan. A recess is formed in the radial center of the rear end surface of the motor,
The fan is an axial fan,
The outer rotor type motor according to claim 2, wherein the airflow generated by the fan passes through the recess and flows in a radial direction by the radiation fins. a plurality of heat sink members arranged in a circumferential direction on a rear end surface of the motor, which are separate from the motor;
Each heat sink member has the heat dissipation fin, and the side arranged on the inside in the radial direction is linear,
The outer rotor type motor according to claim 1 or 2, wherein the plurality of heat sink members are adjacent to each other so that end portions of radially inner sides touch each other. The outer rotor type motor according to claim 1 or 2, further comprising a housing that covers the stator and the rotor.