Patent ID: 12237734

DESCRIPTION OF THE EMBODIMENT

In the following, embodiments of the present invention will be described with reference to the drawings.

As illustrated inFIGS.1and2, a motor1includes a housing2, and inside the housing2, there are provided a rotor (a movable element)4which is rotated about an axis of a motor shaft3corresponding to a rotary shaft, and a stator (a stator element)5which is fixed to the housing2such that a small gap (an air gap) is so formed as to surround the outer periphery of the rotor4. The stator5is press-fitted and fixed to the housing2. Since a well-known product can be applied to the rotor4, a detailed description thereof is omitted.

The motor1may be used, for example, as an aircraft electric motor or a drive source of an actuator of a robot, etc., and may also be used as a drive source of a pump or a compressor, and a flywheel electrical storage device, or used for other purposes.

As illustrated inFIG.3, the stator5includes a plurality of laminated plates5tformed to be laminated in an axial direction thereof, and is provided with an annular yoke51located on the outer side, and a plurality of teeth52protruding from an inner peripheral surface of the yoke51toward the motor shaft3. A gap between the teeth52that are adjacent to each other is referred to as a slot53, and the number of the slots53that are provided is the same as the number of the teeth52.

In the slots53formed between the teeth52that are adjacent to each other, coils6wound around the teeth52are respectively arranged. InFIGS.3,6and7, illustration of the coils6wound around the teeth52is omitted.

The stator5includes a mold resin portion30in which the plurality of laminated plates5tand the coils6are molded. That is, the mold resin portion30is an element obtained by mold forming by using a resin material, such as epoxy resin or polyester resin, with the coils6being wound around the teeth52of the stator5. The mold resin portion30has insulating properties, and adhesiveness between the mold resin portion30and the coil6is high.

The mold resin portion30includes a first mold portion30adisposed above the stator5, a plurality of second mold portions30bdisposed inside each of a plurality of slots53, and a third mold portion30cdisposed below the stator5. The first mold portion30ais connected to upper end portions of the plurality of second mold portions30b, and lower end portions of the plurality of second mold portions30bare connected to the third mold portion30c.

That is, in the mold resin portion30, the first mold portion30aand the third mold portion30care connected to each other by the plurality of second mold portions30b. The first mold portion30a, the plurality of second mold portions30b, and the third mold portion30care connected along an axial direction of the stator5. Inner peripheral portions of the plurality of second mold portions30bare connected in a circumferential direction, and play the role as a wedge.

The mold resin portion30includes a flow path32for a cooling medium to which a cooling medium is supplied. In each of the plurality of slots53, one second mold portion30bis disposed, and in each second mold portion30b, one flow path32is disposed along the axial direction of the stator5.

Each flow path32is formed to pass through one slot53, and the mold resin portion30includes a plurality of flow paths32formed in every one of the slots53of the plurality of slots53, respectively. In the present embodiment, the flow path32for the cooling medium is formed by a through hole penetrating in an axial direction of the second mold portion30b.

An upper end portion of the flow path32formed in the second mold portion30bextends to an upper end surface of the first mold portion30a, and a lower end portion of the flow path32extends to a lower end surface of the third mold portion30c. Consequently, the flow path32penetrates from an upper end surface to a lower end surface of the mold resin portion30.

The flow path32is disposed closer to the rotor4side than the coil6with respect to a radial direction, within the slot53. That is, within the slot53, the flow path32is disposed radially outside relative to a gap (a gap portion) between the stator5and the rotor4, and radially inside relative to the coil6.

In the second mold portion30b, two coil passage portions33aand33b, which are disposed radially outside each flow path32, are formed. The coil passage portion33ais disposed radially outside the flow path32, and the coil passage portion33bis disposed radially outside the coil passage portion33a. That is, when mold forming is performed by using a resin material with the coils6being wound around the teeth52of the stator5, as the second mold portions30bare formed around the coils6, the coil passage portions33aand33bare formed.

On the upper end surface of the mold resin portion30, or more specifically, the upper end surface of the first mold portion30a, an annular groove portion61ais formed. On the lower end surface of the mold resin portion30, or more specifically, the lower end surface of the third mold portion30c, an annular groove portion61bis formed. The annular groove portions61aand61bare formed to be concave at the upper end surface and the lower end surface of the mold resin portion30. An upper end of each of the plurality of flow paths32is open at a bottom surface of the groove portion61a, and a lower end of each of the plurality of flow paths32is open at a bottom surface of the groove portion61b. Accordingly, the plurality of flow paths32communicate with each of the annular groove portions61aand61b.

The housing2includes a cylindrical portion2a, and two cover members2band2cwhich close both sides of the cylindrical portion2a. The cylindrical portion2ais disposed along a vertical direction, the cover member2bcloses an upper end of the cylindrical portion2a, and the cover member2ccloses a lower end of the cylindrical portion2a. Hole portions12aare formed in the cover members2band2c, respectively, and a bearing portion12bwhich rotatably and pivotally supports the motor shaft3is disposed in each of the hole portions12a. A space between the cover member2band the motor shaft3, and a space between the cover member2cand the motor shaft3are sealed by an annular seal member12c.

A supply port60afor a cooling medium is formed in the cover member2bof the housing2. The supply port60ais so formed as to penetrate through the cover member2bin an up-down direction, in which a lower end of the supply port60ais located above the groove portion61aformed on the upper end surface of the mold resin portion30, and the supply port60acommunicates with the groove portion61a.

Similarly, a discharge port60bfor the cooling medium is formed in the cover member2cof the housing2. The discharge port60bis so formed as to penetrate through the cover member2cin the up-down direction, in which an upper end of the discharge port60bis located below the groove portion61bformed on the lower end surface of the mold resin portion30, and the discharge port60bcommunicates with the groove portion61b.

An outer peripheral surface of the mold resin portion30is in contact with an inner peripheral surface of the cylindrical portion2a, and both end portions of the mold resin portion30are disposed to be opposed to the two cover members2band2c, respectively. In other words, the upper end surface of the mold resin portion30is opposed to a lower surface of the cover member2b, and the lower end surface of the mold resin portion30is opposed to an upper surface of the cover member2c. A step portion2dprotruding to the inner side in the radial direction is formed in a lower end portion of the cylindrical portion2a, and an upper surface of the step portion2dis in contact with a lower surface of the stator5.

Four annular seal members62a,63a,62b, and63bare disposed between both end surfaces of the mold resin portion30and the two cover members2band2c. That is, two annular seal members62aand63aare disposed between the upper end surface of the mold resin portion30and the lower surface of the cover member2b. Also, two annular seal members62band63bare disposed between the lower end surface of the mold resin portion30and the upper surface of the cover member2c.

Between the upper end surface of the mold resin portion30and the lower surface of the cover member2b, the annular seal member62ais disposed radially inside the groove portion61a, and the annular seal member63ais disposed radially outside the groove portion61a. Between the lower end surface of the mold resin portion30and the upper surface of the cover member2c, the annular seal member62bis disposed radially inside the groove portion61a, and the annular seal member63bis disposed radially outside the groove portion61a.

In the motor1of the present embodiment, a space at the inner side relative to an inner peripheral surface of the stator5is maintained in a decompressed state. Therefore, the rotor4is rotated in a decompression space.

As illustrated inFIG.2, a pump65is connected to the supply port60aand the discharge port60bfor the cooling medium via connection pipes64aand64b. Thus, when the pump65is driven, the cooling medium is supplied to the supply port60avia the connection pipe64a. The cooling medium supplied to the supply port60apasses through the groove portion61a, and is supplied to the flow path32of the mold resin portion30. The cooling medium which has passed through the flow path32downwardly passes through the groove portion61band reaches the discharge port60b. The cooling medium which has reached the discharge port60is returned to the pump65via the connection pipe64bto be circulated.

A method of manufacturing the stator5used in the motor1of the present embodiment will be described with reference toFIG.8.

(Step S1)

The coils6are wound around the teeth52formed by the plurality of laminated plates5tformed to be laminated, and the plurality of laminated plates5ton which the coils6are wound are arranged inside a cylindrical lower die for mold forming. At the bottom of the lower die for mold forming, a step portion, which is of the same shape as the step portion2dformed in the cylindrical portion2aof the housing2of the motor1, is formed.

(Step S2)

In the interior of the lower die for mold forming, a columnar first cutting die is arranged on the inner side of the plurality of laminated plates5ton which the coils6are wound. The first cutting die is used to form the inner peripheral surface of the stator5, and to form a space in which the rotor4is to be disposed radially inside the stator5, and the diameter of the first cutting die is slightly greater than the diameter of the rotor4.

(Step S3)

In the interior of the lower die for mold forming, one columnar second cutting die is arranged within each of the plurality of slots53in the plurality of laminated plates5ton which the coils6are wound. The second cutting die is used to form the flow path32for a cooling medium within the plurality of slots53. A plurality of second cutting dies are disposed in every one of the plurality of slots53, respectively.

(Step S4)

An upper die for mold forming is mounted onto the lower die for mold forming, and the plurality of laminated plates5ton which coils6are wound are accommodated inside a forming die formed of the upper die for mold forming and the lower die for mold forming. A resin supply port is formed in the upper die for mold forming, and resin is poured into the forming die through the resin supply port of the upper die for mold forming. Thereafter, a resin52is cured in the forming die by cooling or heating. Consequently, the mold resin portion30is formed.

(Step S5)

When the resin52is cured in the forming die, the forming die is separated, and the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded is taken out. When the first cutting die arranged on the inner side of the plurality of laminated plates5t, and the second cutting dies arranged within the plurality of slots53in the plurality of laminated plates5tare removed from the mold resin portion30, manufacturing of the stator5including the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded is completed. In the stator5which has been manufactured, a space in which the rotor4is disposed is formed at a part where the first cutting die is removed, and the flow paths32within the plurality of slots53are also formed at parts where the second cutting dies are removed.

As described above, the motor1of the present embodiment corresponds to a motor including the stator5, and the rotor4, which is disposed with a gap from the stator5, being arranged in the housing2, in which the stator5is provided with a plurality of laminated plates5tforming the yoke51having an annular shape, and the plurality of teeth52protruding from an inner peripheral portion of the yoke51toward the rotor4; the slots53in which the coils6wound around the teeth52are arranged are respectively formed between the teeth52that are adjacent to each other; the stator5includes the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded; the mold resin portion30includes the flow path32formed within at least one slot53among a plurality of slots53; and the flow path32is supplied with a cooling medium.

As can be seen, according to the present embodiment, the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded in the stator5includes the flow paths32for a cooling medium, which are formed within every one of the slots53, respectively. Thus, it is possible to form a stator including the flow paths32to which a cooling medium is supplied by using a conventional laminated plate and without using a dedicated laminated plate for forming the flow paths32to which the cooling medium is supplied. In addition, since the flow paths32to which the cooling medium is supplied are formed in the mold resin portion30, it is possible to suppress an increase in eddy-current loss which is caused by a magnetic flux generated in the stator5or the rotor4, thereby preventing the motor efficiency from decreasing.

In this case, each of the flow paths32is disposed closer to the rotor4side than the coil6within the slot53.

By such a configuration, it is possible to have the flow path32arranged closer to the rotor4side than the coil6within the slot53. Therefore, since the flow paths32are disposed near a gap (a gap portion) between the stator5and the rotor4, which causes the temperature of a portion near the rotor4in the stator5to be lowered, it is possible to reduce a rise in temperature of the rotor4caused by radiation from the stator5. Accordingly, the life of the bearing12bis increased by suppressing an increase in the bearing temperature of the motor shaft3supporting the rotor4.

Specifically, the housing2includes the cylindrical portion2a, and two cover members2band2cwhich close both sides of the cylindrical portion2a; the mold resin portion30includes the plurality of flow paths32which pass through every one of the plurality of slots53, respectively, and the annular groove portions60aand60b, which are formed on the both end surfaces of the mold resin portion30, respectively, and communicate with the plurality of flow paths32; an outer peripheral portion of the mold resin portion30is in contact with the inner peripheral surface of the cylindrical portion2a; and the both end portions of the mold resin portion30are disposed to be opposed to the two cover members2band2c, respectively.

Consequently, the annular groove portions60aand60b, which communicate with the plurality of flow paths32that pass through every one of the plurality of slots53, respectively, are formed on the both end surfaces of the mold resin portion30. Therefore, by allowing a cooling medium to be supplied to the groove portions60aand60bof the mold resin portion30, the cooling medium is made to pass through the plurality of flow paths32.

Further, in the above motor1, the annular seal members62a,62b,63a, and63b, which are disposed radially inside and radially outside the groove portions60aand60b, respectively, are disposed between the both end surfaces of the mold resin portion30and the two cover members2band2c.

Consequently, it is possible to prevent the cooling medium from leaking out inside the motor1, and also maintain the interior of the housing2to be decompressed.

Further, the rotor4of the motor1is rotated in a decompression space.

Consequently, in the decompression space, since generation of a convection flow is significantly reduced even when the rotor4is rotated, the heat of the rotor4is confined. Even in such a case, the temperature of the rotor4can be lowered in the present invention.

Further, a method of manufacturing the stator5corresponds to a method of manufacturing the stator5including a plurality of laminated plates5tforming the annular yoke51and the plurality of teeth52protruding from an inner peripheral portion of the yoke51toward the rotor4, in which the method includes: a first step of winding the coils6around the teeth52, and arranging the plurality of laminated plates5ton which the coils6are wound inside a lower die for mold forming: a second step of arranging, in the interior of the lower die for mold forming, a first cutting die for forming an inner peripheral surface of the stator5on the inner side of the plurality of laminated plates5ton which the coils6are wound; a third step of arranging, in the interior of the lower die for mold forming, a second cutting die for forming the flow path32for a cooling medium within at least one slot53of the plurality of slots53, which are formed between the teeth52that are adjacent to each other, in the plurality of laminated plates5ton which the coils6are wound; a fourth step of forming a forming die by mounting an upper die for mold forming onto the lower die for mold forming, and pouring resin into the forming die and curing the resin; and a fifth step of taking out, after the resin has been cured in the forming die, the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded from the forming die, and removing the first cutting die and the second cutting die from the mold resin portion30.

Consequently, according to the method of manufacturing the stator5of the present embodiment, the mold resin portion30in which the plurality of laminated plates5tand the coils6are molded in the stator5includes the flow paths32for a cooling medium, which are formed within every one of the slots53, respectively. Thus, it is possible to form the stator5including the flow paths32to which a cooling medium is supplied by using a conventional laminated plate and without using a dedicated laminated plate for forming the flow paths32to which the cooling medium is supplied. In addition, since the flow paths32to which the cooling medium is supplied are formed in the mold resin portion30, in the motor1including the stator5and the rotor4, it is possible to suppress an increase in eddy-current loss which is caused by a magnetic flux generated in the stator5or the rotor4, thereby preventing the motor efficiency from decreasing.

Note that the specific configuration is not limited only to the embodiment described above.

In the above embodiment, the mold resin portion30includes a plurality of flow paths32formed in every one of the slots53of the plurality of slots53, respectively. However, the motor of the present invention includes one provided with a mold resin portion30including a flow path32formed within at least one slot53among the plurality of slots53.

In the above embodiment, in the mold resin portion30, the flow path32formed within the slot53is formed by a through hole which penetrates through the mold resin portion30. However, the flow path32formed within the slot53is not limited to a through hole. For example, the number, the shape, a cross-sectional shape and the like of the flow path32formed within one slot53are arbitrary.

In the above embodiment, the flow path32is disposed closer to the rotor4side than the coils6within the slot53. However, the arrangement of the flow path32within the slot53is not limited to the above.

In the above embodiment, the plurality of flow paths32communicate with the groove portions61aand61b, and a cooling medium is supplied to the plurality of flow paths32through the groove portions61aand61b. However, the cooling medium may be supplied to the plurality of flow paths32without passing through the groove portions61aand61b.

In the above embodiment, while the seal member12cis arranged between the housing2and the motor shaft3, a member to be arranged is not limited to the above. A space between the housing2and the motor shaft3may be sealed by, for example, liquid packing or a metal seal.

In the above embodiment, the motor1in which the rotor4is rotated in a decompression space has been described. However, the motor of the present invention is not limited to a motor in which the rotor is rotated in a decompression space.

In the above embodiment, while an inner rotor type motor1has been described, the present invention is applicable to an outer rotor type motor.

Also, in the above embodiment, while a radial gap type motor1has been described, the present invention is applicable to an axial gap type motor.

In the above embodiment, the stator5is press-fitted and fixed to the housing2, but the method of fixing the stator5to the housing2is not limited to the above. By forming a hole which penetrates through the laminated plate5tof the stator5in the axial direction, and forming a screw hole in a surface which comes into contact with an end surface of the stator5at the housing2, fixing to the housing2may be achieved by passage through the hole of the laminated plates5tby use of a bolt.

INDUSTRIAL APPLICABILITY

The present invention can be utilized as a motor including a coil wound on a stator and a method of manufacturing a stator.

REFERENCE SIGNS LIST

1. . . Motor2. . . Housing2a. . . Cylindrical portion2b,2c. . . Cover member4. . . Rotor5. . . Stator5t. . . Laminated plate6. . . Coil30. . . Mold resin portion32. . . Flow path51. . . Yoke52. . . Teeth53. . . Slot60a,60b. . . Groove portion62a,62b,63a,63b. . . Annular seal member