Patent ID: 12249897

DESCRIPTION OF THE EMBODIMENTS

According to the disclosure, in an electromechanical integrated motor integrated with a driver circuit, it is possible to avoid short-circuiting of the driver circuit even if the metal motor cover is deformed. Problems, configurations, and effects other than those described above will be clarified 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 disposed in an engine room, for example, such that the motor2faces an engine and the fan3faces 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.3and4.FIG.3is a perspective diagram showing a front surface side of a configuration of the motor2with the rotor yoke232removed.FIG.4is a longitudinal sectional diagram of the motor2.

As shown inFIGS.3and4, 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 driver case15is formed of a material (e.g. aluminum, iron, stainless steel, etc.) that is conductive and is not easily deformed and broken when external force is applied.

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.3and4, 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”.

As shown inFIG.4, 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.

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. Moreover, the electronic components that make up the driver circuit12are not disposed on a rear surface side of the substrate13that faces the driver case15.

FIG.5is a longitudinal sectional diagram of the motor bracket14and the driver case at the position of a driver insulator40.FIG.6is an exploded perspective diagram of components disposed on the rear surface side of the motor bracket14.

As shown inFIGS.5and6, terminals25A,25B,25C are attached to the front surface of the substrate13. The terminals25A,25B,25C electrically connect the driver circuit12and the coils243. The brushless motor11has the three terminals25A,25B,25C so as to supply three-phase (U-phase, V-phase, W-phase) power to the plurality of coils243. In other words, the brushless motor11is a three-phase AC motor.

As shown inFIG.5, the terminals25A,25B,25C are fixed in contact with the substrate13by screws26A,26B and26C. As shown inFIG.6, the screws26A,26B, and26C include columnar shank portions27A,27B, and27C having male screws formed on an outer circumferential surface, and head portions28A,28B, and28C provided on base end sides of the shank portions27A,27B, and27C.

Moreover, by inserting the shank portions27A,27B, and27C from the rear surface side of the substrate13into through holes13A,13B, and13C penetrating the substrate13in the thickness direction, and screwing nuts with the terminals25A,25B,25C sandwiched on the front surface side of the substrate13, the terminals25A,25B,25C are fixed to the substrate13. On the other hand, the head portions28A,28B, and28C protrude from the rear surface of the substrate13toward the driver case15side. The screws26A,26B, and26C are made of a conductive material such as metal.

Further, washers29A,29B,29C and the driver insulator40are interposed between the rear surface of the substrate13and the head portions28A,28B,28C. The washers29A,29B,29C are ring-shaped members made of metal, and are disposed between the substrate13and the head portions28A,28B,28C to prevent the screws26A,26B,26C from loosening. The screws26A,26B,26C, the washers29A,29B,29C, and the nuts (not shown) are examples of a conductive fixing member that makes the terminals25A,25B,25C contact and fixed to the substrate13. However, the combination of the components of the fixing member is not limited to the above examples.

(Configuration of Driver Insulator40)

(A) and (B) ofFIG.7are perspective diagrams of the driver insulator40. The driver insulator40according to this embodiment includes bottom walls41A,41B,41C; peripheral walls42A,42B,42C; bosses43A,43B,43C; claws44A,44B,44C; and bridges45A,45B. The driver insulator40is made of an insulating material (e.g. resin).

The driver insulator40includes three sets of the bottom wall:41A,41B,41C; the peripheral wall:42A,42B,42C; the boss:43A,43B,43C; and the claw:44A,44B,44C, corresponding to the three terminals25A,25B,25C respectively. Since the components of each set are common, the bottom wall41A, the peripheral wall42A, the boss43A, and the claw44A will be described below.

The bottom wall41A has a disk-shaped outer shape corresponding to a shape of the washer29A. An opening46A penetrating in the thickness direction is formed in a center of the bottom wall41A. A diameter of the opening46A is larger than a diameter of the shank portion27A of the screw26A and smaller than a diameter of the head portion28A. In other words, the shank portion27A may pass through the opening46A, and the head portion28A cannot pass through the opening46A.

The peripheral wall42A is disposed so as to surround the opening46A on one side (the driver case15side) of the bottom wall41A in the thickness direction. The peripheral wall42A has a cylindrical outer shape. More specifically, the peripheral wall42A protrudes from the bottom wall41A and continues in the circumferential direction. Moreover, a protrusion amount of the peripheral wall42A is higher than a height of the head portion28A. In other words, when the screw26A and the driver insulator40are attached to the rear surface of the substrate13, a tip of the peripheral wall42A is disposed closer to the driver case15than the head portion28A of the screw26A. Furthermore, an inner diameter dimension of the peripheral wall42A is the same as or slightly larger than an outer dimension of the washer29A.

The boss43A is formed so as to surround the opening46A on the other side (the substrate13side) of the bottom wall41A in the thickness direction. In other words, the boss43A protrudes from the bottom wall41A in an opposite direction to the peripheral wall42A. The boss43A has a cylindrical outer shape. An inner diameter dimension of the boss43A is slightly larger than a diameter of the shank portion27A. Moreover, an outer dimension of the boss43A is slightly smaller than a diameter of the through hole13A formed in the substrate13. Furthermore, a protrusion amount of the boss43A is smaller than a thickness dimension of the substrate13.

The claws44A are formed at predetermined intervals (e.g. 120°) at a plurality of positions (e.g. three positions) spaced apart in the circumferential direction of the peripheral wall42A. Further, the claw44A protrudes inward in the radial direction from an inner circumferential surface of the peripheral wall42A. The diameter of virtual circle connecting tips of the plurality of claws44A is slightly smaller than the outer dimension of the washer29A. Further, the claw44A is formed with an axial gap from the bottom wall41A. The gap between the bottom wall41A and the claw44A is slightly larger than the thickness of the washer29A.

The bridge45A connects the adjacent peripheral walls42A and42B. Similarly, the bridge45B connects the adjacent peripheral walls42B,42C. Thereby, the components of the driver insulator40are integrated. In this embodiment, an example in which the three peripheral walls42A,42B,42C are linearly connected are described, but the positions of the three peripheral walls42A,42B,42C may be appropriately changed according to the layout of the terminals25A,25B,25C.

(Assembly Procedure for Motor2)

Next, a procedure for assembling the substrate13, the driver case15, the terminals25A-25C, the screws26A-26C, the washers29A-29C, and the driver insulator40will be described.

First, the terminals25A-25C are attached to the front surface of the substrate13. Thereby, the terminals25A-25C are electrically connected to the driver circuit12. Moreover, the washers29A-29C are fitted into inner sides the peripheral walls42A-42C so as to pass over the claws44A-44C. Thereby, the washers29A-29C are held between the bottom walls41A-41C and the claws44A-44C.

Next, the bosses43A-43C are inserted into the through holes13A-13C from the rear surface side of the substrate13. Thereby, surfaces of the bottom walls41A-41C on which the bosses43A-43C are formed come into contact with the rear surface of the substrate13. Moreover, openings of the washers29A-29C, openings46A-46C of the bottom walls41A-41C, internal spaces of the bosses43A-43C, and the through holes13A-13C of the substrate13communicate with each other.

Next, the screws26A-26C are inserted into the through holes13A-13C from the rear surface side of the substrate13. More specifically, tips of the shank portions27A-27C are inserted into the openings of the washers29A-29C, the openings46A-46C of the bottom walls41A-41C, the internal spaces of the bosses43A-43C, and the through holes13A-13C of the substrate13. Then, on the front surface side of the substrate13, the screws26A-26C and the nuts are screwed together with the terminals25A-25C interposed therebetween. Thereby, the terminals25A-25C are fixed in contact with the front surface of the substrate13.

Next, the terminals25A-25C are electrically connected to the coils243. Furthermore, the motor bracket14and the driver case15are joined with the substrate13interposed therebetween. Thereby, the substrate13is accommodated in the accommodation space.

According to the embodiment, for example, the following effects are achieved.

According to the embodiment, by surrounding the head portions28A-28C with the peripheral walls42A-42C that protrude to a position closer to the driver case15from the head portions28A-28C, even if the driver case15is deformed toward the substrate13by an external force, the driver case15hits the peripheral walls42A-42C before the head portions28A-28C. Thereby, the driver case15is prevented from coming into contact with the head portions28A-28C and short-circuiting the driver circuit12.

Moreover, in this embodiment, an example in which the head portions28A-28C are surrounded by the peripheral walls42A-42C that are continuous in the circumferential direction has been described, the configuration of the driver insulator40for preventing contact between the driver case15and the head portions28A-28C is not limited to thereto. As another example, the driver insulator40may have a plurality of projections disposed at predetermined intervals in the circumferential direction at a position surrounding the head portions28A-28C. Further, the plurality of protrusions need only protrude to a position closer to the driver case15than the head portions28A-28C.

Further, of the components of the fixing member for fixing the terminals25A-25C to the substrate13, those closest to the driver case15are not limited to the head portions28A-28C of the screws26A-26C. In other words, the peripheral walls42A-42C need only protrude to a position further closer to the driver case15than the portions (e.g. the washers29A-29C) disposed closest to the driver case15among the components of the fixing member.

Further, according to the embodiment, by providing the claws44A-44C for holding the washers29A-29C, the driver insulator40with the washers29A-29C attached may be assembled to the substrate13. Thereby, the work of assembling the driver insulator40to the substrate13is facilitated. However, the claws44A to44C may be omitted.

Further, according to the embodiment, by providing the bosses43A-43C inserted into the through holes13A-13C of the substrate13, the driver insulator40may be easily positioned with respect to the substrate13. However, the bosses43A-43C may be omitted.

Further, according to the embodiment, by connecting the plurality of the peripheral walls42A-42C with the bridges45A and45B, the components of the driver insulator40are integrated. Thereby, the work of assembling the driver insulator40to the substrate13is further facilitated. However, the three sets of the bottom wall:41A-41C and the peripheral wall:42A-42C may be made independent by omitting the bridges45A and45B.

The driver insulator40according to this embodiment helps prevent contact between the driver case15and the screws26A-26C when an amount of deformation of the driver case15is relatively small. However, if the driver case15is largely deformed, there is a possibility that the driver circuit12will be short-circuited due to contact between the driver case15and the screws26A-26C.

Thus, the driver circuit12according to this embodiment may include an output circuit (e.g. a circuit composed of six transistors) that outputs power to the coils243, and a so-called “Circuit Open Failure detection circuit” that detects that an overcurrent has flowed to the output circuit and stops the supply of power to the output circuit. Thereby, even if the driver case15is largely deformed to such an extent that the possibility of short-circuiting of the driver circuit12cannot be avoided by the driver insulator40alone, it is possible to prevent overcurrent from continuing to flow through the driver circuit12. In addition, since the configuration of the Circuit Open Failure detection circuit is already well known, detailed description thereof will be omitted.

In the 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.

The embodiments of the disclosure have been described above. Moreover, the disclosure is not limited to the above embodiments, and includes various modifications. For example, the above embodiments have been described in detail in order to explain the disclosure in an easy-to-understand manner, and are not necessarily limited to having all the configurations described. Further, a part of the configuration of the embodiments 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 the embodiments. Furthermore, it is possible to add, delete, or replace a part of the configuration of the embodiments with another configuration.