JP7779754B2 - Motor and fan device - Google Patents

Description

The present invention relates to a motor and a fan device equipped with the motor.

In recent years, efforts have been made to promote the Sustainable Development Goals (2030 Agenda for Sustainable Development, adopted at the United Nations Summit on September 25, 2015, hereinafter referred to as "SDGs"). Accordingly, technologies that aim to reduce waste and defective products in order to ensure sustainable production and consumption patterns have become well known.

Outer rotor brushless motors, which rotate a rotor yoke located outside the stator, are used, for example, as motors to drive cooling fans. In order to adjust the rotational balance of the rotor yoke in such motors, putty may be applied to the rotor yoke (see, for example, Patent Document 1), or a solid balance adjustment pin may be press-fitted into a through-hole in the rotor yoke.

JP 2012-095405 A

However, with the method described in Patent Document 1, if the putty is not firmly attached to the rotor yoke, there is a risk that it will peel off while the rotor yoke is rotating. Furthermore, with the method of press-fitting solid balance adjustment pins into the through-holes of the rotor yoke, there is a risk that the rotor yoke will deform when the balance adjustment pins are press-fitted unless the press-fit allowance is set with high precision. This results in issues such as increased motor manufacturing costs and reduced yields.

The object of the present invention is to provide a technology that improves yield at low cost for motors that use balance adjustment pins to adjust rotational balance.

In order to achieve the above object, the present invention provides a motor comprising a motor bracket, a shaft fixed to the motor bracket, a rotor yoke rotatably supported on the shaft, a plurality of permanent magnets fixed to the rotor yoke at intervals in the circumferential direction, and a stator fixed to the motor bracket inside the plurality of permanent magnets and wound with a coil that generates a magnetic field for rotating the rotor yoke, the rotor yoke being disposed radially outward of the stator and having a cylindrical outer peripheral wall that supports the plurality of permanent magnets on its inner peripheral surface, and a coil that is disposed radially inward of the stator and has a cylindrical outer peripheral wall that supports the plurality of permanent magnets on its inner peripheral surface. the balance adjustment pin has a cylindrical inner peripheral wall that is placed on the shaft and rotatably supported on the shaft, and a disk-shaped connecting wall that connects one axial end of the outer peripheral wall and the inner peripheral wall, the connecting wall having a plurality of through holes that penetrate the wall in the thickness direction at positions spaced apart in the circumferential direction, and further having a balance adjustment pin that is press-fitted into at least one of the plurality of through holes , the balance adjustment pin having a cylindrical shape with a slit that extends axially in part of the circumferential direction, the outer dimension of the tip being smaller than the radial opening width of the through hole, and the outer dimension of the center being larger than the radial opening width of the through hole .

This invention enables motors that use balance adjustment pins to adjust their rotational balance to improve yield at low cost. Issues, configurations, and advantages other than those described above will become clear from the description of the following embodiments.

1 is an external perspective view showing an example of the configuration of a fan device according to an embodiment; FIG. 2 is an exploded perspective view of the motor and the fan. FIG. 2 is a perspective view of the motor as viewed from the front side. FIG. 2 is a perspective view showing the configuration of the motor with the rotor yoke removed. 4 is a cross-sectional view taken along line VV in FIG. 3. FIG. 4 is a diagram showing the configuration of a balance adjustment pin. FIG. 10 is a plan view of the rotor yoke with balance adjustment pins attached thereto. FIG. 8 is a cross-sectional view of a main part showing the position of the waterline when the rotor yoke shown in FIG. 7 is tilted. 10 is a flowchart showing the steps of a rotational balance adjustment method. FIG. 10 is a perspective view of the rotor yoke in the process of adjusting the rotational balance.

The following describes one aspect of a fan device according to an embodiment of the present invention, which is mounted on a vehicle such as an automobile and cools engine coolant flowing through a radiator.

(Overall configuration of fan device 1)
First, the overall configuration of a fan device 1 will be described with reference to Figures 1 and 2. Figure 1 is an external perspective view showing an example of the configuration of a fan device 1 according to an embodiment. Figure 2 is an exploded perspective view of a motor 2 and a fan 3 disassembled.

As shown in Figures 1 and 2, the fan unit 1 includes a motor 2, which serves as a drive source, and a fan 3, which is rotated and driven by the motor 2 to generate cooling air. The fan unit 1 is disposed, for example, in an engine compartment, facing the radiator. For example, when the vehicle body is positioned on a horizontal plane, the fan unit 1 is disposed in the engine compartment so that the shaft 21 of the motor 2 extends horizontally. However, if the vehicle body tilts, the extension direction of the shaft 21 will also tilt from the horizontal.

The fan 3 is fastened to the motor 2 with a number of screws 10. The screws 10 are threaded from the front side of the fan 3 (the side opposite the side facing the motor 2) through threaded holes formed in the boss portion 31 at the center of the fan 3, and fastened to the rotor yoke 232 of the motor 2.

In this embodiment, taking into consideration the rotational balance of the fan 3, three screws 10 are attached at equal intervals on a circle centered on the rotation center of the fan 3. Note that it is not necessary to use three screws 10 as fastening members for fastening the fan 3 to the motor 2; there are no particular restrictions on the number of screws 10 or the type of fastening member as long as the fan 3 can be fastened to the motor 2.

The fan 3 has a boss 31 that rotates integrally with the rotor 23, with the center of rotation being on the axis of the shaft 21, multiple blades 32 (seven in this embodiment) that extend radially from the outer periphery of the boss 31, and multiple connecting members 33 (seven in this embodiment) that connect adjacent blades 32 at their tips.

The boss portion 31 includes a disk-shaped disk portion 311 positioned opposite the connecting wall 232C of the rotor yoke 232, and a peripheral wall portion 312 that extends from the outer edge of the disk portion 311 to the outside of the outer peripheral wall 232A of the rotor 23 and has multiple blades 32 attached to it.

(Configuration of Motor 2)
Next, the configuration of the motor 2 will be described with reference to Figures 3 to 5. Figure 3 is an external perspective view of the motor 2 as seen from the front side. Figure 4 is a perspective view showing the configuration of the motor 2 without the rotor yoke 232. Figure 5 is a cross-sectional view taken along line VV in Figure 3.

As shown in Figures 3 to 5, motor 2 is an electric motor that includes an outer rotor brushless motor 201 and a driver circuit 202 that controls brushless motor 201 (generation of a magnetic field by coil 243).

As shown in Figure 3, the brushless motor 201 is supported by the motor bracket 203. The brushless motor 201 is disposed on one side (front surface side) of the motor bracket 203 in the thickness direction.

As shown in Figure 5, the driver bracket 204 is fastened to the other thickness side (back side) of the motor bracket 203 with multiple screws 205. This forms an accommodation space 206 between the motor bracket 203 and the driver bracket 204. The driver circuit 202 is then housed in this accommodation space 206.

In addition, a connector unit 207, which combines two connectors to which an external harness is connected, is attached to the end of the motor bracket 203. The brushless motor 201, driver circuit 202, and connector unit 207 are electrically connected to each other via the motor bracket 203.

As shown in Figures 4 and 5, the brushless motor 201 has a shaft 21, bearings 22A and 22B provided on the outer periphery of the shaft 21, a rotor 23 rotatably supported around the axis of the shaft 21 via the bearings 22A and 22B, and an annular stator 24 wound with a coil 243 that generates a magnetic field for rotating the rotor 23.

The shaft 21 is a fixed shaft fixed to the motor bracket 203. In the following description of the components of the motor 2, the axial direction of the shaft 21 will be referred to simply as the "axial direction," the radial direction centered on the axis of the shaft 21 will be referred to simply as the "radial direction," and the circumferential direction centered on the axis of the shaft 21 will be referred to simply as the "circumferential direction."

The rotor 23 has multiple permanent magnets 231 arranged at equal intervals in the circumferential direction around the outer periphery of the stator 24, and a rotor yoke 232 that covers the stator 24 and the multiple permanent magnets 231.

As shown in FIG. 5, the rotor yoke 232 is disposed on the surface side of the motor bracket 203 so as to be concentric with the axis of the shaft 21. The rotor yoke 232 is rotatably supported on the shaft 21 via bearings 22A and 22B. The rotor yoke 232 includes an outer peripheral wall 232A, an inner peripheral wall 232B, a connecting wall 232C, and a yoke flange 232D.

The outer peripheral wall 232A has a cylindrical outer shape. Furthermore, the outer peripheral wall 232A is positioned radially outward from the stator 24. Furthermore, the inner peripheral surface of the outer peripheral wall 232A supports multiple permanent magnets 231. In other words, the multiple permanent magnets 231 are fixed to the inner peripheral surface of the outer peripheral wall 232A at predetermined intervals in the circumferential direction.

The inner peripheral wall 232B has a cylindrical outer shape. Furthermore, the inner peripheral wall 232B is positioned radially inward from the stator 24. Furthermore, the inner peripheral wall 232B is rotatably supported on the shaft 21 via bearings 22A and 22B.

The connecting wall 232C has a disk-shaped outer shape. The connecting wall 232C connects one axial end of the outer peripheral wall 232A and one axial end of the inner peripheral wall 232B. Furthermore, as shown in Figures 3 and 5, the connecting wall 232C has a plurality of through holes 233 formed therein.

The multiple through holes 233 are formed at predetermined intervals in the circumferential direction on an imaginary circle centered on the shaft 21. The multiple through holes 233 also penetrate the connecting wall 232C in the thickness direction. The multiple through holes 233 are elongated holes extending in the circumferential direction and having an arc-shaped outer shape. A balance adjustment pin 25 may be press-fitted into at least one of the multiple through holes 233 to adjust the rotational balance of the rotor yoke 232. The multiple through holes 233 also function as drainage ports to drain water that has entered the rotor yoke 232.

As shown in FIG. 5 , the multiple through holes 233 are formed in positions where at least a portion of them overlap the permanent magnets 231 when the rotor yoke 232 is viewed in a plan view from the axial direction. Furthermore, in this embodiment, there are 10 permanent magnets 231 (an even number) and 9 through holes 233 (an odd number). However, the specific number is not limited to the above example, as long as the permanent magnets 231 are either odd or even, and the through holes 233 are the other of odd and even.

Yoke flange 232D is provided at the other axial end of outer peripheral wall 232A (i.e., the opposite end from connecting wall 232C). Yoke flange 232D also protrudes radially outward from outer peripheral wall 232A. Furthermore, yoke flange 232D extends in the circumferential direction. However, yoke flange 232D does not need to be provided around the entire circumference of outer peripheral wall 232A; a portion may be cut out to adjust the rotational balance of rotor yoke 232.

The stator 24 is housed in a space surrounded by the outer peripheral wall 232A, inner peripheral wall 232B, connecting wall 232C, and motor bracket 203. The stator 24 is fixed to the surface side of the motor bracket 203, radially inward from the multiple permanent magnets 231. The stator 24 faces the multiple permanent magnets 231 across a predetermined radial gap.

As shown in Figures 4 and 5, the stator 24 has a cylindrical stator core 241, insulating insulators 242 attached to both axial sides of multiple teeth that protrude radially outward from the stator core 241, and a conductive coil 243 wound around the insulator 242.

The stator 24 generates a magnetic field when current flows through the coil 243. The magnetic field generated by the coil 243 and the multiple permanent magnets 231 create attractive and repulsive forces that cause the rotor yoke 232 to rotate around the axis of the shaft 21.

(Configuration of balance adjustment pin 25)
FIG. 6 is a diagram showing the configuration of the balance adjustment pin 25. As shown in FIG. 6, the balance adjustment pin 25 has a generally cylindrical outer shape. The balance adjustment pin 25 is hollow and has open axial ends. The balance adjustment pin 25 is composed of a main body 251 and an inclined portion 252. The balance adjustment pin 25 also has a slit 253 formed therein.

The main body 251 has a cylindrical outer shape. The inclined portions 252 are provided at both ends of the main body 251. The inclined portions 252 are inclined so that the outer dimensions decrease as they approach the axial ends of the balance adjustment pin 25. In other words, the balance adjustment pin 25 has a tapered shape. The inclined portions 252 function as guide surfaces when the balance adjustment pin 25 is press-fitted into the through-hole 233.

The slits 253 are formed in part of the circumferential direction of the balance adjustment pin 25. The slits 253 are also formed across the entire axial area of the balance adjustment pin 25. Furthermore, the slits 253 penetrate the balance adjustment pin 25 in the thickness direction. In other words, the balance adjustment pin 25 is configured to be elastically contractible.

That is, as shown in Figure 6 (B), when the balance adjustment pin 25 is viewed in a plan view from the axial direction, the balance adjustment pin 25 has a C-shaped outer shape. The slits 253 are connected to the openings on both axial end faces of the balance adjustment pin 25. The internal space of the balance adjustment pin 25 is open to the outside by both axial end faces and the slits 253. The outer dimensions of the tip (inclined portion 252) of the balance adjustment pin 25 are set smaller than the radial opening width of the through hole 233. Meanwhile, the outer dimensions of the center (main body portion 251) of the balance adjustment pin 25 are set slightly larger than the radial opening width of the through hole 233.

As a result, the tip of the balance adjustment pin 25 can be inserted into the through hole 233. As the balance adjustment pin 25 continues to be inserted into the through hole 233, the outer surface of the balance adjustment pin 25 comes into contact with the circumferential surface that defines the through hole 233, causing the balance adjustment pin 25 to elastically contract in diameter. Then, as shown in Figure 5, when the balance adjustment pin 25 is inserted to a position where it does not come into contact with the permanent magnet 231, the force of the balance adjustment pin 25 elastically expanding its diameter fixes the balance adjustment pin 25 within the through hole 233.

(Drainage of the rotor yoke 232)
Next, the drainage performance of the rotor yoke 232 according to this embodiment will be described with reference to Figures 7 and 8. Figure 7 is a plan view of the rotor yokes 232 and 232' to which balance adjustment pins 25 and 25' are attached. Figure 8 is a cross-sectional view of a main part showing the position of the waterline when the rotor yokes 232 and 232' shown in Figure 7 are tilted.

First, as shown in this embodiment in Figure 7(A), the arc-shaped through-hole 233 into which the C-shaped balance adjustment pin 25 is press-fitted is open at a position adjacent to the balance adjustment pin 25. Therefore, even when the balance adjustment pin 25 is press-fitted, the through-hole 233 can continue to function as a drainage port. Furthermore, because the balance adjustment pin 25 itself penetrates in the axial direction, drainage through the internal space of the balance adjustment pin 25 can also be expected.

In contrast, as shown in Figure 7(B), circular through-holes 233' are formed at predetermined intervals in the circumferential direction in the connecting wall 232C' of a conventional rotor yoke 232'. A solid balance adjustment pin 25' is press-fit into at least one of the through-holes 233'. The outer dimensions of the balance adjustment pin 25' are set slightly larger than the diameter of the through-hole 233'. Therefore, when the balance adjustment pin 25' is inserted into the through-hole 233', it loses its function as a drainage port.

Next, as shown in Figure 8, suppose the motors 2, 2' equipped with the rotor yokes 232, 232' shown in Figure 7 are tilted so that the connecting walls 232C, 232C' face downward, and the through holes 233, 233' into which the balance adjustment pins 25, 25' are press-fitted are positioned at the lowest position. In this case, in the rotor yoke 232 according to this embodiment, water drains from the through hole 233 into which the balance adjustment pin 25 is press-fitted. On the other hand, in the conventional rotor yoke 232', water drains from the other through hole 233' adjacent to the through hole 233' into which the balance adjustment pin 25' is press-fitted. As a result, the rotor yoke 232 according to this embodiment can lower the waterline position compared to the conventional rotor yoke 232'.

(Rotational balance adjustment method)
Next, a method for adjusting the rotational balance of rotor yoke 232 according to this embodiment will be described with reference to Figures 9 and 10. Figure 9 is a flowchart showing the steps of the rotational balance adjustment method. Figure 10 is a perspective view of rotor yoke 232 during the process of adjusting the rotational balance.

First, the rotor yoke 232 is attached to a balance measurement device and rotated to measure the rotational balance (S11). The rotational balance measured here includes static balance and dynamic balance. Static balance refers to balance in the radial direction (vertical direction) perpendicular to the shaft 21. Dynamic balance refers to balance in the axial direction (horizontal direction) of the shaft 21.

Rotational balance is measured on both the first correction plane side (connecting wall 232C side) and the second correction plane side (yoke flange 232D side). The rotational balance (e.g., eccentricity) measured by the balance measurement device is a physical quantity that increases as the degree of imbalance increases. Then, it is determined whether the measured rotational balance on each of the first correction plane side and the second correction plane side is within a preset numerical range (S12, S13).

If the rotational balance on both the first and second correction planes is within the preset numerical range (S12: No & S13: No), balance adjustment is terminated. In other words, if the rotational balance is determined to be within the preset numerical range in the first steps S12 and S13, a rotor yoke 232 is obtained in which the balance adjustment pin 25 is not press-fitted into the through-hole 233 and the yoke flange 232D is not cut out.

Furthermore, if the rotational balance on the first correction plane side is outside the preset numerical range (S12: Yes), as shown in FIG. 10(A), one or more balance adjustment pins 25 are press-fitted into at least one of the multiple through holes 233 (S14), and the processing from step S11 onwards is executed again. Note that the number and positions of the balance adjustment pins 25 to be press-fitted in step S14 are the same as in conventional balance adjustment methods, so explanation will be omitted.

Furthermore, if the rotational balance on the first correction plane side is within a preset numerical range and the rotational balance on the second correction plane side is outside the preset numerical range (S12: No & S13: Yes), a portion of the yoke flange 232D is cut out (S15), and the processing from step S11 onwards is executed again. For example, as shown by the dashed-dotted line in Figure 10(B), a portion of the yoke flange 232D may be cut out along a linear cutting line. However, the method of cutting out the yoke flange 232D is not limited to the above example. Note that the position and extent of the cutout in step S15 is the same as in the conventional balance adjustment method in which the outer surface of the outer peripheral wall 232A is cut, and therefore description thereof will be omitted.

Then, by repeating steps S11 to S15, a rotor yoke 232 with rotational balance adjusted to within a preset numerical range can be obtained.

The above embodiment provides the following advantages, for example:

In the above embodiment, a C-shaped balance adjustment pin 25 having a slit 253 formed therein is press-fitted into the through-hole 233 of the rotor yoke 232. At this time, the balance adjustment pin 25 elastically contracts in diameter to match the size of the through-hole 233, so the rotational balance of the rotor yoke 232 can be appropriately adjusted without requiring a high degree of press-fit accuracy. As a result, a motor 2 can be obtained at low cost and with high yield. By providing an inclined portion 252 at the tip of the balance adjustment pin 25, the above-mentioned effects are further enhanced. Note that, to achieve the above-mentioned effects, the through-hole 233 does not necessarily have to be an arc-shaped hole extending in the circumferential direction; it may also be a perfect circle as shown in Figure 7(B).

Furthermore, according to the above embodiment, by making the through hole 233 an elongated hole with an arc shape extending circumferentially, it is possible to maintain its function as a drainage port even after the balance adjustment pin 25 is press-fitted. This allows the waterline inside the rotor yoke 232 to be lowered. As a result, when the motor 2 is used in an environment where water may enter the rotor yoke 232 (for example, outdoors), drainage inside the motor 2 is improved. Note that in order to achieve the above-mentioned effect, the balance adjustment pin 25 does not necessarily need to have a slit 253 formed in it, and may be solid, as shown in Figure 7(B).

Furthermore, according to the above embodiment, by forming a through hole 233 at a position that overlaps the permanent magnet 231 when the rotor yoke 232 is viewed in a plan view from the axial direction, it is possible to adjust the rotational balance using a lightweight balance adjustment pin 25. This contributes to reducing the weight of the motor 2. It also allows the waterline to be further lowered.

Furthermore, in the above embodiment, by making the axial gap between the balance adjustment pin 25 and the permanent magnet 231 shorter than the length of the balance adjustment pin 25 protruding from the connecting wall 232C to the outside of the rotor yoke 232 (the side opposite the permanent magnet 231), it is possible to prevent the balance adjustment pin 25 from falling off into the rotor yoke 232.

Furthermore, according to the above embodiment, in addition to press-fitting the balance adjustment pin 25 into the through-hole 233, the rotational balance is also adjusted by cutting out a portion of the yoke flange 232D, resulting in a motor 2 with excellent rotational balance. Furthermore, because the method of cutting out the yoke flange 232D does not reduce the magnetic path, it is possible to prevent a decline in the performance of the motor 2 compared to a method of grinding the outer surface of the outer peripheral wall 232A.

Furthermore, according to the above embodiment, the rotational balance of the rotor yoke 232 is adjusted using the procedure shown in Figure 9, thereby optimizing the rotational balance of the rotor yoke 232 with low labor costs.

In the above embodiment, an example was described in which the fan device 1 is used to supply cooling air to a radiator, but the use of the fan device 1 is not limited to this. Furthermore, in the above embodiment, an example was described in which the motor 2 is used as a fan motor that drives the fan 3 to rotate, but the use of the motor 2 is not limited to this.

The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment and includes various modifications. For example, the above embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to having all of the described configurations. Furthermore, it is possible to replace part of the configuration of this embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of this embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of this embodiment with other configurations.

DESCRIPTION OF SYMBOLS 1: Fan device 2, 2': Motor 3: Fan 10, 205: Screw 21: Shaft 22A, 22B: Bearing 23: Rotor 24: Stator 25, 25': Balance adjustment pin 31: Boss portion 32: Blade 33: Connecting member 201: Brushless motor 202: Driver circuit 203: Motor bracket 204: Driver bracket 206: Storage space 207: Connector unit 231: Permanent magnet 232, 232': Rotor yoke 232A, 232A': Outer peripheral wall 232B, 232B': Inner peripheral wall 232C, 232C': Connecting wall 232D, 232D': Yoke flange 233, 233': Through hole 241: Stator core 242: Insulator 243: Coil 251: Main body 252 : Inclined portion 253 : Slit 311 : Disk portion 312 : Peripheral wall portion

Claims (7)

A motor bracket;
a shaft fixed to the motor bracket;
a rotor yoke rotatably supported on the shaft;
a plurality of permanent magnets fixed to the rotor yoke at intervals in the circumferential direction;
a stator fixed to the motor bracket inside the plurality of permanent magnets and wound with a coil that generates a magnetic field for rotating the rotor yoke,
The rotor yoke is
a cylindrical outer wall disposed radially outward of the stator and supporting the plurality of permanent magnets on an inner peripheral surface thereof;
a cylindrical inner peripheral wall disposed radially inward of the stator and rotatably supported by the shaft;
a disk-shaped connecting wall that connects one axial end of the outer peripheral wall and one axial end of the inner peripheral wall,
The connecting wall has a plurality of through holes formed at circumferentially spaced positions, each of the through holes penetrating the connecting wall in a thickness direction,
a balance adjustment pin press-fitted into at least one of the plurality of through holes ;
The balance adjustment pin has a cylindrical shape with a slit extending in the axial direction formed in part of its circumferential direction, and the outer dimension of the tip is smaller than the radial opening width of the through hole, and the outer dimension of the center is larger than the radial opening width of the through hole . 2. The motor according to claim 1,
The motor is characterized in that each of the plurality of through holes is an arc-shaped elongated hole extending in the circumferential direction. 3. The motor according to claim 1,
The motor is characterized in that the plurality of through holes are formed at positions where at least a portion of the through holes overlaps with the permanent magnets when the rotor yoke is viewed in a plan view from the axial direction. The motor according to any one of claims 1 to 3,
the number of the plurality of permanent magnets is one of odd and even;
The motor is characterized in that the number of the plurality of through holes is the other of an odd number and an even number. The motor according to any one of claims 1 to 4,
the rotor yoke has a yoke flange that protrudes radially from the other axial end of the outer peripheral wall and extends circumferentially,
A motor characterized in that a portion of the yoke flange is cut out. The motor according to any one of claims 1 to 5,
The motor is characterized in that the through hole extends in a circumferential direction of the connecting wall. A motor according to any one of claims 1 to 6;
a fan that is rotationally driven by the motor to generate cooling air.