Patent ID: 12247571

DESCRIPTION OF THE EMBODIMENTS

According to the disclosure, it is possible to prevent an overcurrent from flowing even when a shaft contacts a substrate in an electromechanical integrated motor having a driver circuit integrated therein. Problems, configurations, and effects other than those described above will be explained by the following description of the embodiments.

As one aspect of a fan device according to an embodiment of the disclosure, a fan device that is equipped in a vehicle such as an automobile and cools engine cooling water or the like flowing in a radiator will be described below.

(Overall Configuration of Fan Device1)

First, an overall configuration of a fan device1will be described with reference toFIGS.1and2.FIG.1is an external perspective diagram showing a configuration example of the fan device1according to an embodiment.FIG.2is an exploded perspective diagram of a motor2and a fan3.

As shown inFIGS.1and2, the fan device1includes the motor2which is a drive source, and the fan3which is rotationally driven by the motor2to generate cooling air. The fan device1is installed in an engine room, for example, such that the motor2is disposed on a rear side (the side facing an engine) and the fan3is disposed on a front side (the side facing a radiator).

The fan3is fastened to the motor2by a plurality of screws10. The screws are fastened to a rotor yoke232of the motor2from a front side of the fan3(a side opposite to a side facing the motor2) through screw holes formed in a boss portion31serving as a central portion of the fan3. It is not always necessary to use the screws10as fastening members for fastening the fan3to the motor2. As long as the fan3may be fastened to the motor2, the number of screws and the types of fastening members are not particularly limited.

The fan3includes the boss portion31that rotates integrally with a rotor23around an axial center of a shaft21, a plurality of (seven in this embodiment) blades32that project radially from an outer circumference of the boss portion31; and a plurality of (seven in this embodiment) connecting members33that connect the adjacent blades32on a tip side.

The boss portion31includes a disk-shaped disk portion311and a cylindrical peripheral wall portion312protruding from an outer edge of the disk portion311toward the motor2and having the plurality of blades32attached thereto. When the fan3is attached to the motor2, the disk portion311faces a connection wall232C of the rotor yoke232and the peripheral wall portion312surrounds the outer circumferential wall232A of the rotor yoke232.

(Configuration of Motor2)

Next, the configuration of the motor2will be described with reference toFIGS.3to5.FIG.3is an exploded perspective diagram of a brushless motor11, a substrate13, and a driver case15.FIG.4is a perspective diagram showing a front surface side of a configuration of the motor2with the rotor yoke232removed.FIG.5is a longitudinal sectional diagram of the motor2.

As shown inFIGS.3to5, the motor2is a so-called “electromechanical integrated” electric motor including an outer rotor type brushless motor11and a substrate13on which a driver circuit12is mounted.

The brushless motor11is supported by a motor bracket14. The brushless motor11is disposed on one side (front surface side) of the motor bracket14in a thickness direction. A driver case15is fastened to the other side (rear surface side) of the motor bracket14in the thickness direction by a plurality of screws. Thereby, an accommodation space for accommodating the substrate13is formed between a rear surface of the motor bracket14and the driver case15.

In other words, the substrate13is disposed on a side opposite to components21-24of the brushless motor11(the rear surface side of the motor bracket14) with the motor bracket14interposed therebetween. The motor bracket14and the driver case15are made of a material having high thermal conductivity (for example, a metal such as aluminum, iron, or stainless steel). Also, the motor bracket14and the driver case15may be black in order to increase heat absorption rate.

A connector unit16in which two connectors to which an external harness is connected are integrated is attached to an end portion of the motor bracket14. The brushless motor11, the driver circuit12, and the connector unit16are electrically connected.

As shown inFIGS.3-5, the brushless motor11includes the shaft21; a plurality of bearings22provided on an outer circumference of the shaft21; the rotor23rotatably supported around the axial center of the shaft21via the bearings22; and an annular stator24fixed at a predetermined interval from the rotor23in a radial direction.

The shaft21is a fixed shaft fixed to the front surface side of the motor bracket14. In the following description of components of the motor2, an axial direction of the shaft21is simply referred to as the “axial direction”, the radial direction around the axial center of the shaft21is simply referred to as the “radial direction”, and a circumferential direction around the axial center of the shaft21is simply referred to as the “circumferential direction”.

The rotor23includes a plurality of permanent magnets231disposed at equal intervals in the circumferential direction so as to surround an outer circumference of the stator24, and the rotor yoke232that supports the plurality of permanent magnets231and is rotatably supported on the shaft21.

The rotor yoke232is disposed on the front surface side of the motor bracket14so as to be concentric with the axial center of the shaft21. Moreover, the rotor yoke232is rotatably supported by the shaft21via the plurality of bearings22. Furthermore, the rotor yoke232includes an outer circumferential wall232A, an inner circumferential wall232B, and the connection wall232C.

The outer circumferential wall232A has a cylindrical outer shape. Moreover, the outer circumferential wall232A is disposed outward of the stator24in the radial direction. Further, the outer circumferential wall232A supports the plurality of permanent magnets231with an inner circumferential surface. In other words, the plurality of permanent magnets231are fixed to an inner circumferential surface of the outer circumferential wall232A at predetermined intervals in the circumferential direction.

The inner circumferential wall232B has a cylindrical outer shape. Moreover, the inner circumferential wall232B is disposed inward of the stator24in the radial direction. Further, the inner circumferential wall232B is rotatably supported by the shaft21via the plurality of bearings22.

The connection wall232C has a disk-shaped outer shape. Moreover, the connection wall232C connects axial ends of the outer circumferential wall232A and the inner circumferential wall232B. Furthermore, the connection wall232C is disposed on a side opposite to the motor bracket14with the stator24interposed therebetween. The connection wall232C is disposed opposite to the stator24with a predetermined interval in the axial direction.

The stator24is accommodated in a space surrounded by the outer circumferential wall232A, the inner circumferential wall232B, the connection wall232C, and a front surface of the motor bracket14. Moreover, the stator24is fixed to the front surface side of the motor bracket14inward of the plurality of permanent magnets231in the radial direction. Furthermore, the stator24faces the plurality of permanent magnets231with a predetermined gap in the radial direction.

The stator24includes a cylindrical stator core241, a stator insulator242mounted on both sides in the axial direction of a plurality of teeth projecting outward in the radial direction from the stator core241; and conductive coils243wound on the stator insulator242.

The stator24generates a magnetic field when a current flows through the coils243. The rotor yoke232rotates around the axial center of the shaft21due to the magnetic field generated by the coils243and the attractive force and repulsive force generated between the plurality of permanent magnets231.

Moreover, the motor2is disposed in the engine room with the shaft21directed in a traveling direction of a vehicle. The motor2is disposed in the engine room with the brushless motor11facing forward and the driver case15facing rearward.

(Configuration of Driver Circuit12)

FIG.6is a schematic circuit diagram of a power system circuit120included in the driver circuit12.FIG.7is a plan diagram of the substrate13on which the driver circuit12is mounted. The driver circuit12controls generation of the magnetic field by the plurality of coils243. The driver circuit12is composed of a plurality of electronic components (e.g. transistor, diode, resistor, etc.) surface-mounted on a front surface of the substrate13facing the motor bracket14. The substrate13has a plate-like shape made of, for example, an aluminum alloy.

As shown inFIG.6, to supply current from a power source121to the coils243of the brushless motor11, the power system circuit120mainly includes three positive side transistors:122U,122V122W; three negative side transistors:123U,123V,123W; a motor control IC124; and a fuse125(hereinafter, they may be referred to collectively as “power system components121-125”). Moreover, the electronic components that supply current to the coils243are not limited to the power system components121-125described above.

Sources of the positive side transistors122U,122V,122W are connected in parallel to a positive pole of the power source121. Drains of the positive side transistors122U,122V,122W are connected to the coils243of the U phase, V phase, and W phase, respectively. Furthermore, gates of the positive side transistors122U,122V,122W are connected to the motor control IC124.

Sources of the negative side transistors123U,123V,123W are connected to the coils243of the U phase, V phase and W phase, respectively. Moreover, drains of the negative side transistors123U,123V,123W are connected in parallel to a negative pole of the power source121. Furthermore, gates of the negative side transistors123U,123V,123W are connected to the motor control IC124.

In other words, a wiring from the positive pole of the power source121to the coils243via the positive side transistors122U,122V,122W is a positive wiring having a positive potential. Also, a wiring from the coils243to the negative pole of the power source121via the negative side transistors123U,123V,123W is a GND wiring having a ground potential.

The motor control IC124controls ON and OFF of the transistors122U,122V,122W,123U,123V,123W (supply and cutoff of current to the coils243) by controlling the application of voltage to the gate of each transistor122U,122V,122W,123U,123V,123W. The fuse125is disposed between the positive pole of the power source121and the positive side transistors122U,122V,122W, and cuts off the wiring when an overcurrent flows through the power system circuit120.

As shown inFIG.7, the front surface of the substrate13includes regions131and132. Among the wirings forming the driver circuit12, the positive wiring and the power system components121-125are disposed in the region131, and the GND wiring is disposed in the region132. Moreover, the positive wiring and GND wiring described here include not only the wiring of the power system circuit120described with reference toFIG.6, but also the wiring of a control system (e.g. speed controller, speed converter, voltage controller, etc.)

A mark • inFIG.7indicates a position on the substrate13overlapping the shaft21when the motor2is viewed from the axial direction of the shaft21(in other words, a position where the shaft21is extended in the axial direction). As shown inFIG.7, an extension of the shaft21overlaps the region132. That is, the GND wiring of the driver circuit12is mounted on the region132on the substrate13overlapping the shaft21when the motor2is viewed from the axial direction of the shaft21. In other words, the positive wiring and the electronic components of the driver circuit12are mounted outside a region on the substrate13overlapping the shaft21when the motor2is viewed from the axial direction of the shaft21.

A dashed line inFIG.7indicates a position overlapping the outer circumference of the stator24when the motor2is viewed from the axial direction of the shaft21. The power system components121-125are mounted outside a region on the substrate13overlapping the stator24.

Furthermore, as shown inFIG.5, the power system components121-125are in contact with the metal motor bracket14via an adhesive17. It is desirable that the adhesive17has high thermal conductivity.

According to the above embodiment, for example, the following operational effects are obtained.

According to the above embodiment, the GND wiring of the driver circuit12is mounted on the region on the substrate13overlapping the shaft21when the motor2is viewed from the axial direction of the shaft21. Thereby, even if the shaft21passes through the motor bracket14and contacts the substrate13, only the shaft21and the GND wiring having the same potential come into contact with each other, thus overcurrent does not flow throughout the driver circuit12. As a result, it is possible to prevent blowing of the fuse125.

In order to prevent overcurrent from flowing through the driver circuit12, it is only necessary to avoid the shaft21passing through the motor bracket14from coming into contact with the portion of the driver circuit12having positive potential. In other words, it is only necessary that the portion of the driver circuit12having positive potential (typically, the positive wiring) is mounted outside the region on the substrate13overlapping the shaft21when the motor2is viewed from the axial direction of the shaft21. Here, the region on the substrate13overlapping the shaft21may be left unmounted when the motor2is viewed from the axial direction of the shaft21, although from the viewpoint of improving the residual copper rate, the GND wiring is preferably mounted.

Further, according to the above embodiment, the power system components121-125are mounted outside the region on the substrate13overlapping the stator24when the motor2is viewed from the axial direction of the shaft21. In this way, by keeping the power system components121-125that generate heat by themselves away from the coils243, the thermal influence on the coils243can be reduced. Further, since the power system components121-125may be kept away from the shaft21, the influence of heat received from the shaft21on the power system components121-125can be reduced. Thereby, the life of the motor2is extended, contributing to the waste reduction.

Furthermore, according to the above embodiment, since the power system components121-125are brought into contact with the metal motor bracket14via the adhesive17, heat radiation effect is improved. In particular, when the fan3is driven by the motor2, since the motor bracket14is cooled by the cooling air generated by the fan3, the heat dissipation effect is further improved. Thereby, the life of the motor2is extended, contributing to the waste reduction.

In the above embodiment, an example in which the fan device1is equipped in a vehicle driven by an engine has been described, but the fan device1may be equipped in a vehicle driven by a motor, storage battery, fuel cell, or the like. Also, as an application of the fan device1, an example of supplying cooling air to a radiator has been described, but the application of the fan device1is not limited thereto. Furthermore, in the embodiment, as an application of the motor2, an example of a fan motor that rotationally drives the fan3has been described, but the application of the motor2is not limited thereto. Moreover, an example in which the substrate made of aluminum alloy is applied has been described, but the substrate13may be a substrate made of resin such as glass epoxy resin.

The embodiment of the disclosure has been described above. Moreover, the disclosure is not limited to the above embodiment, and includes various modifications. For example, the above embodiment has been described in detail in order to explain the disclosure in an easy-to-understand manner, and is not necessarily limited to having all the configurations described. Further, a part of the configuration of this embodiment may be replaced 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 a part of the configuration of this embodiment with another configuration.