JP7792877B2 - Fan unit - Google Patents

Description

The present invention relates to a fan device.

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 on the outside of the stator, are used, for example, as fan motors to drive automotive cooling fans. Motors used in this type of application need to be able to drain any liquid droplets (e.g., rainwater) that may have entered the motor.

There is a known motor that has a through-hole formed in the bearing holder that connects to a drainage channel formed inside the motor, allowing liquid droplets that have entered the space around the shaft to be drained (see, for example, Patent Document 1).

Patent No. 6132877

However, the technology in Patent Document 1 requires the formation of drainage channels in the gaps between the bracket, stator, and rotor, which makes the motor structure complex and results in longer drainage channels that make it difficult for droplets to be discharged.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fan device that is capable of draining droplets that have entered the space around the shaft with a simple configuration.

In order to achieve the above object, the present invention provides a fan device comprising: a motor including a motor bracket, a shaft having one axial end fixed to the motor bracket, a rotor yoke supporting a plurality of permanent magnets at predetermined intervals in the circumferential direction, a bearing supporting the rotor yoke rotatably relative to the shaft, 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; and a fan that rotates by the driving force of the motor, wherein the rotor yoke is disposed radially outward of the stator and supports the plurality of permanent magnets on its inner peripheral surface. a cylindrical outer peripheral wall disposed radially inward of the stator and supported by the bearing so as to be rotatable relative to the shaft; and a disk-shaped connecting wall connected to the other axial end of the shaft at the other axial end of the shaft, wherein an axial groove extending in the axial direction and opening to the other end of the shaft is formed on at least one of the outer peripheral surface of the bearing and the inner peripheral surface of the inner peripheral wall , the fan is fixed to the connecting wall and rotates, and a surface of the fan that abuts the connecting wall is formed with a plurality of radial grooves extending radially so as to avoid an attachment position with the connecting wall .

This invention allows for the drainage of droplets that have entered the space around the shaft using a simple configuration. Other issues, configurations, and advantages 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. 2 is an exploded perspective view of components around the shaft. 3A and 3B are perspective views of a rotor yoke as viewed from the front side and the back side, respectively. 10A and 10B are diagrams showing variations in the shape of the back surface side of the boss portion. FIG. 2 is a cross-sectional view of the fan and rotor yoke.

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.

(Configuration of Motor 2)
Next, the configuration of the motor 2 will be described with reference to Figures 3 to 7. 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 with the rotor yoke 232 removed. Figure 5 is a cross-sectional view taken along line VV in Figure 3.

As shown in Figures 3 to 5, motor 2 is a so-called "electromechanical integrated" electric motor that includes an outer rotor brushless motor 201 and a driver circuit 202 that controls brushless motor 201 (more specifically, the generation of a magnetic field by coil 243).

The brushless motor 201 is supported by a plate-shaped motor bracket 203. The brushless motor 201 is arranged 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 with one axial end 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."

Figure 6 is an exploded perspective view of the components surrounding the shaft 21. As shown in Figure 6, the brushless motor 201 further includes the shaft 21, a pair of bearings 22A and 22B, and a coil spring 52.

The shaft 21 has a generally cylindrical outer shape. The shaft 21 mainly comprises a first shaft portion 211, a second shaft portion 212, and a flange portion 213.

The first shaft portion 211 and the second shaft portion 212 are portions extending in opposite directions with the flange portion 213 in between. The inner ring of bearing 22A is fitted onto the first shaft portion 211. The inner ring of bearing 22B is fitted onto the second shaft portion 212. In other words, bearings 22A and 22B are spaced apart in the axial direction.

The flange portion 213 is a disk-shaped portion that protrudes radially outward and continues circumferentially between the first shaft portion 211 and the second shaft portion 212. In other words, the diameter of the flange portion 213 is set larger than the diameters of the first shaft portion 211 and the second shaft portion 212. The flange portion 213 functions as a spring seat against which one end of the coil spring 52 abuts.

Bearings 22A and 22B are ball bearings comprising an inner ring, an outer ring, multiple balls arranged between the inner and outer rings, and a retaining portion that maintains the circumferential spacing of the multiple balls. Bearings 22A and 22B are radial bearings that support radial loads. The inner ring of bearing 22A is fitted onto shaft 21, and the outer ring is fitted into inner circumferential wall 232B. The inner ring of bearing 22B is fitted onto shaft 21, and the outer ring is fitted into inner circumferential wall 232B. Bearings 22A and 22B thus support rotor yoke 232 rotatably relative to shaft 21.

The coil spring 52 is fitted onto the first shaft portion 211 between the bearing 22A and the flange portion 213. The coil spring 52 biases the bearing 22A toward the fan 3. This presses the flange portion 213 against the bearing 22B.

As shown in Figure 5, the rotor 23 has a plurality of permanent magnets 231 arranged at equal intervals in the circumferential direction so as to surround the outer periphery of the stator 24, and a rotor yoke 232 that covers the stator 24 and the plurality of permanent magnets 231. The rotor yoke 232 is arranged 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.

Figure 7 is a perspective view of the rotor yoke 232 viewed from the front side (A) and back side (B). As shown in Figures 5 and 7, the rotor yoke 232 has an outer peripheral wall 232A, an inner peripheral wall 232B, and a connecting wall 232C.

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 the axial ends of the outer peripheral wall 232A and the inner peripheral wall 232B. More specifically, as shown in FIG. 5, the connecting wall 232C connects the outer peripheral wall 232A and the inner peripheral wall 232B at the other axial end of the shaft 21 (i.e., the side opposite the motor bracket 203).

Furthermore, the rotor yoke 232 is formed with a plurality of axial grooves 233 (three in this embodiment). The axial grooves 233 extend in the axial direction on the inner circumferential surface of the inner circumferential wall 232B. The axial grooves 233 are also formed at a plurality of positions spaced apart circumferentially (at 120° intervals in this embodiment). However, the number and spacing of the axial grooves 233 are not limited to the above example; for example, six axial grooves 233 may be formed at 60° intervals.

As shown in FIG. 5, the axial groove 233 is recessed radially outward from the inner circumferential surface of the inner circumferential wall 232B. One end of the axial groove 233 (the end on the motor bracket 203 side) is located between the pair of bearings 22A, 22B. The other end of the axial groove 233 (the end on the connecting wall 232C side) is open.

As a result, a gap is formed between the outer surface of bearing 22A and the inner surface of inner peripheral wall 232B by axial groove 233. As a result, the space formed between bearings 22A, 22B, shaft 21, and inner peripheral wall 232B (hereinafter referred to as the "space around shaft 21") is connected to the outside of motor 2 (fan 3 side) through axial groove 233. In other words, liquid droplets that have entered the space around shaft 21 are discharged to the outside of motor 2 through axial groove 233.

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 protruding 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 Fan 3)
As shown in Figures 1 and 2, the fan 3 has a boss portion 31 that rotates integrally with the rotor 23, with the axis of the shaft 21 as the center of rotation, a plurality of blades 32 (seven in this embodiment) that extend radially from the outer periphery of the boss portion 31, and a plurality of connecting members 33 (seven in this embodiment) that connect adjacent blades 32 at their tips.

The boss portion 31 also includes a disk-shaped disk portion 311 and a cylindrical peripheral wall portion 312 that protrudes from the outer edge of the disk portion 311 toward the motor 2 and has multiple blades 32 attached to it. When the fan 3 is attached to the motor 2, the disk portion 311 faces the connecting wall 232C of the rotor yoke 232, and the peripheral wall portion 312 surrounds the outer peripheral wall 232A of the rotor yoke 232.

Figure 8 shows variations in the shape of the back surface of the boss portion 31 (the surface facing the connecting wall 232C). As shown in Figure 8, the disk portion 311 is formed with multiple screw holes 313 and multiple radial grooves 314A, 314B.

A plurality of screw holes 313 penetrate the disk portion 311 in the thickness direction in a ring-shaped region of the disk portion 311 that abuts the connecting wall 232C. The screw holes 313 are formed at predetermined intervals in the circumferential direction (120° intervals in this embodiment). However, the number of screw holes 313 and their circumferential spacing are not limited to the above example.

As shown in FIG. 2, the fan 3 is fastened to the rotor yoke 232 by screws 10 threaded into the screw holes 313. In this embodiment, three screws 10 are attached at equal intervals on a circle centered on the rotation center of the fan 3, taking into consideration the rotational balance 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; as long as the fan 3 can be fastened to the motor 2, there are no particular restrictions on the number of screws 10 or the type of fastening member.

The multiple radial grooves 314A, 314B are formed on the surface of the disk portion 311 facing the connecting wall 232C of the fan 3 in a ring-shaped region that abuts against the connecting wall 232C. The multiple radial grooves 314A, 314B are formed radially, avoiding the screw holes 313 (i.e., the attachment position to the connecting wall 232C). More specifically, the multiple radial grooves 314A, 314B extend radially, passing between adjacent screw holes 313 in the circumferential direction.

As one example, as shown in FIG. 8(A), the radial grooves 314A may extend linearly in the radial direction. As another example, as shown in FIG. 8(B), the radial grooves 314B may curve radially outward in the opposite direction (i.e., clockwise) to the rotation direction of the fan 3 (counterclockwise in the example of FIG. 8(B)).

Figure 9 is a cross-sectional view of the fan 3 and rotor yoke 232. As indicated by the arrows in Figure 9, liquid droplets that have entered the space around the shaft 21 are discharged through the axial groove 233 into the space between the fan 3 and rotor yoke 232 (i.e., the side opposite the motor bracket 203). Next, the liquid droplets in the space between the fan 3 and rotor yoke 232 are discharged radially outward through the radial grooves 314A and 314B due to the centrifugal force generated by the rotation of the fan 3 and rotor yoke 232.

In addition, an axial gap exists between the fan 3 and rotor yoke 232 radially outside the ring-shaped region where the disk portion 311 and connecting wall 232C abut. Therefore, droplets discharged from the radial grooves 314A, 314B by centrifugal force are discharged to the outside of the fan unit 1 through this gap. On the other hand, droplets that enter this gap from the outside of the fan unit 1 may enter the inner circumferential wall 232B through the radial grooves 314A, 314B and the axial groove 233.

For this reason, the fan unit 1 further includes a narrow portion 315. The narrow portion 315 is located radially outward of the radial grooves 314A and 314B, between the fan 3 and the connecting wall 232C. The narrow portion 315 is also selectively located on the extension of the radial grooves 314A and 314B within the circumferentially continuous gap between the fan 3 and the connecting wall 232C. As a result, the gap between the fan 3 and the connecting wall 232C on the extension of the radial grooves 314A and 314B is narrower than in other areas. However, the narrow portion 315 does not completely close the gap between the fan 3 and the connecting wall 232C, but rather maintains a certain degree of gap.

As a result, it is possible to prevent droplets from entering the radial grooves 314A and 314B from outside the fan device 1. Meanwhile, centrifugal force acts on droplets discharged from the radial grooves 314A and 314B, causing them to bypass the narrow portion 315 and be discharged outside the fan device 1.

The narrow portion 315 may be attached to the fan 3 or the rotor yoke 232. The specific shape of the narrow portion 315 is not particularly limited, and may be a wall, pillar, rib, etc.

The above embodiment provides the following advantages, for example:

In the above embodiment, simply by providing the axial groove 233, liquid droplets that have entered between the shaft 21 and the inner peripheral wall 232B can be discharged to the side opposite the motor bracket 203 of the motor 2. This makes it possible to drain liquid droplets that have entered the space around the shaft 21 with a simple configuration. As a result, rust on the shaft 21, bearings 22A, 22B, and coil spring 52 can be prevented, extending the life of the fan unit 1 and contributing to reducing waste.

Furthermore, according to the above embodiment, by providing axial grooves 233 at multiple positions spaced apart in the circumferential direction, it is possible to properly discharge droplets from the space around the shaft 21 regardless of the orientation of the motor 2 when it is installed. However, if the orientation of the motor 2 when it is installed is fixed, the axial grooves 233 may be provided only below the shaft 21.

Furthermore, according to the above embodiment, by providing radial grooves 314A and 314B, droplets discharged through axial groove 233 can be efficiently discharged to the outside of fan device 1. When fan 3 rotates both clockwise and counterclockwise, by forming radial groove 314A in a straight line, as shown in FIG. 8(A), droplets can be discharged regardless of the rotation direction of fan 3. On the other hand, when fan 3 rotates in only one direction, by curving radial groove 314B in the opposite direction to the rotation direction of fan 3, as shown in FIG. 8(B), droplets inside can be discharged and droplets can be prevented from entering from the outside.

Furthermore, according to the above embodiment, by selectively providing narrow sections 315 on the extension lines of the radial grooves 314A and 314B, it is possible to prevent the intrusion of droplets without interfering with the discharge of droplets due to the action of centrifugal force.

In the above embodiment, an example was described in which the axial groove 233 was formed on the inner circumferential surface of the inner circumferential wall 232B, but the position of the axial groove 233 is not limited to the above example. As another example, the axial groove 233 extending in the axial direction may be formed on the outer circumferential surface of the bearing 22A that contacts the inner circumferential wall 232B. In other words, the axial groove 233 may be formed on at least one of the outer circumferential surface of the bearing 22A and the inner circumferential surface of the inner circumferential wall 232B.

Furthermore, in the above embodiment, an example was described in which the fan device 1 was 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 was used as a fan motor that rotates and drives the fan 3, 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: Motor 3: Fan 10, 205: Screw 21: Shaft 22A, 22B: Bearing 23: Rotor 24: Stator 31: Boss portion 32: Blade 33: Connecting member 52: Coil spring 201: Brushless motor 202: Driver circuit 203: Motor bracket 204: Driver bracket 206: Housing space 207: Connector unit 211: First shaft portion 212: Second shaft portion 213: Flange portion 231: Permanent magnet 232: Rotor yoke 232A: Outer peripheral wall 232B: Inner peripheral wall 232C: Connecting wall 233: Axial groove 241: Stator core 242: Insulator 243: Coil 311: Disk portion 312: Peripheral wall portion 313: Screw holes 314A, 314B : Radial groove 315 : Narrow part

Claims (6)

A motor bracket;
a shaft having one axial end fixed to the motor bracket;
a rotor yoke that supports a plurality of permanent magnets at predetermined intervals in the circumferential direction;
a bearing that rotatably supports the rotor yoke relative to the shaft;
a motor including 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 ;
a fan rotated by the driving force of the motor,
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 supported by the bearing so as to be rotatable relative to the shaft;
a disk-shaped connecting wall that connects ends of the outer circumferential wall and the inner circumferential wall at the other axial end side of the shaft,
an axial groove extending in the axial direction and opening toward the other end side of the shaft is formed on at least one of the outer circumferential surface of the bearing and the inner circumferential surface of the inner circumferential wall ;
the fan is fixed to the connecting wall and rotates;
a plurality of radial grooves extending radially to avoid a mounting position with respect to the connecting wall are formed on the surface of the fan that abuts against the connecting wall ; The fan device according to claim 1,
the rotor yoke is rotatably supported on the shaft by a pair of the bearings spaced apart in the axial direction,
The axial groove extends in the axial direction on the inner surface of the inner wall, with one axial end located between the pair of bearings and the other axial end open to the connecting wall side. The fan device according to claim 1,
The fan device is characterized in that the axial grooves are formed at a plurality of positions spaced apart in the circumferential direction. The fan device according to claim 1 ,
The fan device is characterized in that the radial grooves extend linearly in the radial direction. The fan device according to claim 1 ,
The fan device, wherein the radial grooves are curved radially outward in a direction opposite to the rotation direction of the fan. The fan device according to claim 1 ,
a narrowed portion that narrows a gap between the fan and the connecting wall, the narrowed portion being located radially outward of the radial groove and on an extension of the radial groove;