Patent Description:
A molded motor is known as a motor which has a structure of a stator covered with mold resin to reduce noise and vibration of the motor. With a recent increase in motor output or the like, this type of molded motor generates a larger amount of heat from coils wound around a stator core. Accordingly, a problem of thermal deterioration of the mold resin has been arising.

For preventing this thermal deterioration of the mold resin, PTL <NUM> discloses a use of an epoxy resin which contains a filler having high thermal conductivity as the mold resin. The use of this resin increases heat dissipation from the mold resin, thereby preventing thermal deterioration.

Additionally, a technique which improves electrical insulation of a molded motor has been proposed. For example, PTL <NUM> discloses a motor which increase dielectric strength by reducing generation of voids (cavities) generated in the case of molding with resin and affecting electrical insulation. Furthermore, PTL <NUM> discloses a motor stator configured to satisfy sufficient dielectric voltage for a thickness of insulating resin surrounding a periphery of a motor. However, if excessive currents flow in coils wound around a stator core for some reasons and increase temperatures of the coils with generation of heat from the coils, an insulator that insulates outer circumferential surfaces of coil conductors may melt and cause short-circuiting between the coil conductors. If the conductors are short-circuited and generate sparks, the sparks may ignite gas generated from insulating resin or the like provided between the coils and the stator core and heated. Furthermore, if the mold resin is thermally deteriorated and forms cracks or the like by generation of heat from the coils, generated sparks may leak from a cracked portion of the mold resin to the outside of the motor.

In addition, according to the method which achieves improvement to secure electrical insulation by a structural change for a space not filled with resin or generated voids as in PTL <NUM> or PTL <NUM>, this change may affect strength or electrical characteristics, and deteriorate the strength or the electrical characteristics even if electrical insulation is secured. Furthermore, PTL <NUM> or PTL <NUM> which adopts the method of controlling a flow of resin or air during injection of injection molding by a structural change also causes a problem that this method is difficult to introduce with ease in view of an effect of the change on a manufacturing step as well.

Document <CIT> discloses a dynamo-electric machine comprising an assembly of a wound stator, a housing part constituting an end shield having a circular trough which accommodates the end turns of the winding, spacer means, e.g. perforated foil, between the end turns and the housing part and a cylindrical member within and coaxial with the stator, introducing a settable material into the assembly which acts as a mould and removing the cylindrical member after the material has set.

Document <CIT> discloses a motor which eliminates the use of a complicated metal mold, and improves design freedom.

The present invention has been developed in consideration of the aforementioned problems. A main object of the present invention is to provide a molded motor capable of reducing an increase in a size of a motor external shape while securing electrical insulation, and capable of preventing leakage of fire to the outside of the motor even if excessive currents flow in coils wound around a stator core.

For achieving the above object, a molded motor of the present inventionhas the features of claim <NUM>.

Provided according to the present invention is a molded motor capable of reducing an increase in a size of a motor external shape while securing electrical insulation, and capable of preventing leakage of fire to the outside of the motor even if excessive currents flow in coils wound around a stator core.

Before describing an exemplary embodiment of the present invention, circumstances that have led to development of the present invention are described.

The inventors of the present application focused on coil ends axially protruding from a stator core to take a measure (non-combustion measure) for preventing leakage of fire to the outside of a motor as a result of a flow of excessive currents in coils wound around the stator core.

Specifically, the coils wound around the stator core are surrounded by the stator core except for the coil ends axially protruding from the stator core. Accordingly, there is substantially no possibility of leakage of ignited fire to the outside of the motor. On the other hand, the coil ends protrude from the stator core, and therefore are in contact with mold resin. Accordingly, if cracks or the like are produced near the mold resin in contact with the coil ends, the ignited fire may leak from a cracked portion of the mold resin to the outside of the motor.

Concerning this point, the inventors of the present application have noticed, as a non-combustion measure, that fire leaked from the cracked portion of the mold resin can be cut off by a metal member provided on an outer surface of the mold resin at a portion facing the coil ends.

Meanwhile, when the metal member is provided on the outer surface of the mold resin, a maximum withstanding voltage between the metal member and the coils, i.e., a dielectric voltage, needs to be considered. The dielectric voltage is specified by Electrical Appliance and Material Safety Act. On the other hand, miniaturization of a molded motor of the type described in the present invention is achievable by reducing a thickness of the mold resin, for example. In this case, a sufficient dielectric voltage as described above needs to be secured.

In particular, examples of a method generally adopted for forming the molded motor include a method which fixes a stator and the like inside a mold, and filling melted mold resin in the mold for molding. In this case, bubbles may be generated when the melted mold resin is poured into the mold. These bubbles may remain in a completed solid mold resin as minute spaces called voids. It is known that voids or spaces in which the resin is not sufficiently filled act to lower a dielectric breakdown voltage, and affect electrical insulation.

The present invention has been developed based on the above findings, and provides a molded motor capable of reducing an increase in a size of a motor external shape while securing electrical insulation, and capable of preventing leakage of fire to the outside of the motor even if excessive currents flow in coils wound around a stator core.

An exemplary embodiment of the present invention, a non-claimed example and non-claimed modifications are hereinafter described with reference to the drawings. Note that the exemplary embodiment described below shows one specific example of the present invention. Therefore, numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, connection forms, and the like shown in the following exemplary embodiment are examples and are not intended to limit the present invention. Therefore, constituent elements included in the following exemplary embodiment and not recited in the independent claim that indicates a most generic concept of the present invention are described as optional constituent elements.

Note that each of the drawings is a schematic view, and does not necessarily show a strict illustration. Furthermore, in each of the drawings, substantially identical configurations are given identical reference numerals, and the same description is omitted or simplified.

<FIG> is an exploded perspective view of motor (hereinafter also referred to as molded motor where appropriate) <NUM> according to an exemplary embodiment of the present invention. <FIG> is a half cross-sectional view of motor <NUM>. <FIG> is a cross-sectional plan view as viewed from arrow <NUM>-<NUM> of <FIG>.

As shown in <FIG>, motor <NUM> includes rotor <NUM>, stator <NUM>, bearings <NUM>, mold resin portion <NUM>, metal outer cover <NUM> as a metal member, and insulating film <NUM> as an insulating material.

Rotor <NUM> includes rotary shaft <NUM> extending in axial direction X, and rotor core <NUM>. Rotor core <NUM> holds permanent magnets (hereinafter also referred to as magnets where appropriate) <NUM>, and is fixed to rotary shaft <NUM>.

Stator <NUM> includes stator core <NUM> where a plurality of members each constituting tooth (also referred to as teeth to indicate a plurality of members each constituted by tooth) 11t as salient poles are arranged in circumferential direction Z, and a plurality of coils <NUM> each wound via insulators <NUM> around corresponding tooth 11t as a salient pole of stator core <NUM>. Stator <NUM> faces rotor <NUM>.

Bearings <NUM> support rotor <NUM> such that rotor <NUM> is freely rotatable. Motor <NUM> adopts a pair of bearings <NUM>. Note that similar effects can be produced if a cantilever bearing is employed.

Mold resin portion <NUM> covers stator <NUM> with mold resin.

Metal outer cover <NUM> as a metal member is mounted on an outer surface of mold resin portion <NUM>. Metal outer cover <NUM> includes cylindrical portion 31c having a cylindrical shape, and bottom surface portion 31a forming a bottom surface of cylindrical portion 31c.

Insulating film <NUM> as an insulating material is located between mold resin portion <NUM> and metal outer cover <NUM> as a metal member. At least a part of a surface of insulating film <NUM> is arranged at a portion facing the plurality of coils <NUM> arranged in circumferential direction Z.

In particular, a following configuration produces remarkable operations and effects.

According to motor <NUM> of the present exemplary embodiment, each of the plurality of coils <NUM> includes coil ends 12a protruding from stator core <NUM> toward both sides in axial direction X. Cylindrical portion 31c included in metal outer cover <NUM> as a metal member is located on an outer circumferential surface of mold resin portion <NUM> at least at a portion facing coil ends 12a on both sides.

Insulating film <NUM> as an insulating material has a cup shape which has a hole in a bottom surface portion of insulating film <NUM>. Insulating film <NUM> is interposed between an inner surface of metal outer cover <NUM> and an outer surface of mold resin portion <NUM>.

Further details are described with reference to the drawings.

As shown in <FIG>, motor <NUM> has rotor <NUM> including permanent magnets. Motor <NUM> is a brushless motor which covers a coil assembly of stator <NUM> with mold resin. According to the present exemplary embodiment, motor <NUM> is described as an example of the brushless motor. As shown in <FIG>, a direction indicated by X where rotary shaft <NUM> extends is defined as an axial direction. In the following description, it is assumed that a Y direction extending from center X of rotary shaft <NUM> is a radial direction, and that a Z direction surrounding center X is a circumferential direction in a plane orthogonal to axial direction X as shown in <FIG>.

According to the present exemplary embodiment, a metal member as a non-combustion measure is provided for the mold resin to prevent leakage of fire or smoke from a main body of motor <NUM> to the outside as a result of a problem such as an excessive current flow in the coils. Specifically, metal outer cover <NUM> made of metal is provided as the metal member. Metal outer cover <NUM> has a cup shape.

According to motor <NUM>, as shown in <FIG> and <FIG>, insulating film <NUM> as an insulating material is interposed between the outer surface of mold resin portion <NUM> and the inner surface of metal outer cover <NUM> to secure a dielectric voltage between coils <NUM> and metal outer cover <NUM>.

An overall configuration of motor <NUM> is described. As shown in <FIG>, motor <NUM> includes stator <NUM> covered with mold resin portion <NUM> as a mold resin, rotor <NUM>, bearings 30A, 30B as a pair of bearings <NUM>, metal outer cover <NUM> as a metal member, and insulating film <NUM> as an insulating material. Motor <NUM> further includes circuit board <NUM> and first bracket <NUM>.

As shown in <FIG>, stator <NUM> includes coil assembly <NUM> which includes stator core <NUM>, coils <NUM>, and insulators <NUM>. Coil assembly <NUM> is assembled by winding each of coils <NUM> around a corresponding salient pole of stator core <NUM> via insulators <NUM> made of an insulating material.

Stator core <NUM> is constituted by a plurality of thin iron plates laminated in axial direction X, for example. As shown in <FIG>, stator core <NUM> has ringshaped yoke 11y, and a plurality of teeth 11t as salient poles extending inward in radial direction Y from an inner circumferential surface of yoke 11y. The plurality of teeth 11t are arranged at equal intervals in circumferential direction Z while forming slots <NUM> as openings between respective teeth 11t. The present exemplary embodiment shows an example where <NUM> slots are formed by the plurality of teeth 11t. In the following description, terms "teeth" (plural form of tooth) and "tooth" are used differently for each case. Specifically, a plurality of salient poles protruding toward a center of stator core <NUM> are referred to as teeth, while one salient pole of the plurality of salient poles is referred to as a tooth.

Tooth tip end portion 11tb formed at an extended tip end portion of each tooth 11t extends in circumferential direction Z to become wider than extended tooth middle portion 11ta. An inner circumferential surface of tooth tip end portion 11tb constitutes a magnetic pole surface facing an outer circumferential surface of rotor <NUM>. Each of coils <NUM> is formed by winding wire 12w around corresponding tooth 11t of stator core <NUM> thus configured while allowing winding wire 12w to pass through an opening space of slot <NUM>. Coils <NUM> are connected to each other by crossover wires for connecting respective coils <NUM>. Moreover, a wire terminal of predetermined coil <NUM> is connected to pins (not shown) attached to insulators <NUM>. Each of the pins herein is a metal electrical connection member for an electrical connection terminal. Each tip of the pins protrudes from a terminal cap as a driving terminal. For example, coil <NUM> for each tooth 11t is energized and driven by three-phase alternating current, that is, a U-phase, a V-phase, and a W-phase electrically different from each other in phase by <NUM> degrees.

Furthermore, as shown in <FIG>, stator <NUM> includes second bracket <NUM> arranged so as to protrude from the main body of stator <NUM>. Coil assembly <NUM>, second bracket <NUM>, and terminal cap <NUM> are arranged at predetermined positions of stator <NUM>. These members except for an exposed portion are covered with a resin material to be integrally molded with mold resin. The resin material herein is not particularly limited. For example, an epoxy resin, a polyester resin, or the like having excellent thermal conductivity is adoptable.

Stator <NUM> including mold resin portion <NUM> which integrates the foregoing members with the mold resin is configured in this manner. Stator <NUM> configured as above has a substantially cylindrical shape. A wiring hole through which wiring holder <NUM> is mounted, and others are also formed in a cylindrical surface of stator <NUM>. An inner circumferential surface of each tooth 11t and a terminal surface of terminal cap <NUM> are exposed as the exposed portion from mold resin portion <NUM>. Furthermore, one of both circular surfaces of stator <NUM> is open, and first bracket <NUM> is mounted to cover this opening. The other surface is closed. As described above, second bracket <NUM> is so arranged as to protrude. A configuration of stator <NUM> is described in detail below.

As shown in <FIG>, rotor <NUM> is inserted inside stator <NUM> with a predetermined clearance left from stator <NUM> in radial direction Y. That is, motor <NUM> is an inner rotor type motor which includes rotor <NUM> arranged inside stator <NUM>. According to motor <NUM>, the inner circumferential surface of stator <NUM> and the outer circumferential surface of rotor <NUM> face each other in radial direction Y with gap <NUM> as a short clearance left therebetween. Motor <NUM> of an inner rotor type is hereinafter described by way of example.

Rotor <NUM> includes rotor core <NUM> which holds permanent magnets <NUM> around rotary shaft <NUM> rotatably held by the pair of bearings <NUM>. The pair of bearings <NUM> herein are ball bearings each of which has a plurality of balls 30b each having a small diameter as shown in <FIG>. Specifically, each of bearings <NUM> is configured such that balls 30b are inserted between outer ring 30o having an annular shape and inner ring 30i having an annular shape and smaller than outer ring 30o. Outer ring 30o of one bearing 30A of the pair of bearings <NUM> is fixed by first bracket <NUM>, while outer ring 30o of other bearing 30B is fixed by second bracket <NUM>. In addition, rotary shaft <NUM> is fixed to inner ring 30i of each of bearings 30A, 30B.

Rotor core <NUM> is constituted by a plurality of thin iron plates laminated in axial direction X, for example, and is fixed to rotary shaft <NUM>. Magnets <NUM> are permanent magnets, and are arranged inside rotor core <NUM>.

As shown in <FIG>, a plurality of magnet insertion holes 23c penetrating in axial direction X are formed in rotor core <NUM> at equal intervals in circumferential direction Z. Magnets <NUM> are inserted into magnet insertion holes 23c one for each. The present exemplary embodiment shows motor <NUM> of an interior permanent magnet (IPM) type which includes magnets <NUM> contained inside rotor core <NUM>. In addition, shown is an example where ten magnets <NUM> are arranged with S poles and N poles of magnetic poles of magnets <NUM> alternately disposed in circumferential direction Z to constitute ten magnetic poles. Accordingly, presented in the present exemplary embodiment is an example of motor <NUM> which is a brushless motor having <NUM> poles and <NUM> slots. While motor <NUM> of the inner rotor type is presented by way of example in the present exemplary embodiment, the motor may be motor <NUM> of a surface permanent magnet motor type (SPM type) which includes rotor <NUM> retaining magnets <NUM> on an outer circumferential surface of rotor core <NUM> as shown in <FIG> is an exploded perspective view of a different motor according to the exemplary embodiment of the present invention.

As described above, rotor <NUM> is constituted by rotor core <NUM> having a cylindrical shape as shown in <FIG>, a plurality of magnets <NUM> held inside rotor core <NUM>, and rotary shaft <NUM> penetrating a center of rotor core <NUM>.

Rotary shaft <NUM> is rotatably supported by bearings 30A, 30B. Bearings 30A, 30B are fixed via first bracket <NUM> and second bracket <NUM> which are made of metal and arranged on one and the other sides of stator <NUM> in axial direction X, respectively.

As shown in <FIG> and <FIG>, first bracket <NUM> has a substantially disc shape, and is configured to be mounted on the opening side of stator <NUM>. Furthermore, holding portion 35a recessed in a cylindrical shape is formed in a central portion of first bracket <NUM>. Bearing 30A is held on holding portion 35a. Accordingly, one side of rotary shaft <NUM> is rotatably supported on stator <NUM> by mounting first bracket <NUM> with bearing 30A inserted into holding portion 35a. Furthermore, as shown in <FIG>, opening 35b is formed at a center of holding portion 35a. Rotary shaft <NUM> penetrates opening 35b and protrudes outward. A protruding portion of rotary shaft <NUM> constitutes output shaft 21p to which a load or the like is connected. In the following description, a side where output shaft 21p is arranged is referred to as an output shaft side, and a side opposite to this side is referred to as a side opposite to the output shaft in axial direction X.

Second bracket <NUM> has a smaller diameter than a diameter of first bracket <NUM>, and has a shape formed by combining a disc and a cylinder. Second bracket <NUM> is fixed to mold resin portion <NUM> of stator <NUM> by molding described above. Holding portion 15a recessed in a cylindrical shape is similarly formed in a central portion of second bracket <NUM>. Bearing 30B is held on holding portion 15a. Accordingly, the other side of rotary shaft <NUM> is rotatably supported on stator <NUM> by inserting bearing 30B into holding portion 15a.

In addition, metal outer cover <NUM> made of metal is mounted on the side where second bracket <NUM> of stator <NUM> is disposed, that is, the side opposite to the output shaft, with insulating film <NUM> interposed. As shown in <FIG>, metal outer cover <NUM> has a hollow cup shape having opening <NUM> at a center of metal outer cover <NUM>. In the example presented herein, insulating film <NUM> similarly has a hollow cup shape having opening <NUM> at a center of insulating film <NUM>, and has a shorter length in axial direction X than a length of metal outer cover <NUM>. Metal outer cover <NUM> is mounted on stator <NUM> in such a manner that second bracket <NUM> included in stator <NUM> penetrates opening <NUM> of metal outer cover <NUM> and opening <NUM> of insulating film <NUM>. Detailed configurations of metal outer cover <NUM> and insulating film <NUM> are also further described below.

According to the configuration of the present exemplary embodiment, motor <NUM> has such a configuration where circuit board <NUM> is built in on the opening side of stator <NUM>. Circuit board <NUM> has a substantially disc shape, and has opening 34b at a central portion of circuit board <NUM> as an opening through which rotary shaft <NUM> passes. Electronic component 34a such as a drive circuit is mounted on circuit board <NUM>, and a connection line and the like for applying a power supply voltage or a control signal are also connected to circuit board <NUM>. Connection line <NUM> for connecting to the outside is drawn out to the outside via wiring holder <NUM> mounted in the wiring hole.

As shown in <FIG>, terminal cap <NUM> integrated with mold resin portion <NUM> is arranged in an inner space on the opening side of stator <NUM> to draw out the wire terminals of coils <NUM> from an inside of mold resin portion <NUM> of stator <NUM>. Terminal cap <NUM> is a member made of an insulating resin, and including an array plate portion for arranging electrical connection terminals such as pins. The wire terminals of coils <NUM> and the like are connected to the electrical connection terminals. According to the present exemplary embodiment, electrical connection with circuit board <NUM> is made using exposed portions of pins, for example, and circuit board <NUM> is held by terminal cap <NUM> in the inner space of stator <NUM>.

Motor <NUM> described above is constituted based on following procedures.

First, stator <NUM> is constituted by arranging coil assembly <NUM>, second bracket <NUM>, and terminal cap <NUM> at predetermined positions in a mold, and performing integral molding with resin. Bearings 30A, 30B are mounted on one and the other sides of rotary shaft <NUM> of rotor <NUM>, respectively. Rotor <NUM> to which bearings 30A, 30B are mounted is inserted into stator <NUM> such that output shaft 21p protrudes from opening 35b of first bracket <NUM>.

Subsequently, bearing 30B is press-fitted into holding portion 15a of second bracket <NUM>.

Thereafter, circuit board <NUM> is mounted on terminal cap <NUM> on the opening side of stator <NUM>. Connection line <NUM> connected to circuit board <NUM> is drawn to the outside via wiring holder <NUM>. Bearing 30A is press-fitted into holding portion 35a of first bracket <NUM>, while first bracket <NUM> is mounted on the opening side of stator <NUM> so as to cover the opening.

Finally, metal outer cover <NUM> and insulating film <NUM> are mounted on a side closer to second bracket <NUM> of stator <NUM>. In this manner, motor <NUM> shown in <FIG> is completed.

Coils <NUM> are energized and driven, using a drive circuit mounted on circuit board <NUM>, by supplying a power supply voltage, a control signal, or the like to motor <NUM> configured as above via connection line <NUM>. When coils <NUM> are energized, drive currents flow in coils <NUM>, and a magnetic field is generated from stator core <NUM>. Thereafter, an attractive force and a repulsive force are generated by an alternating magnetic field from stator core <NUM> and a magnetic field from magnets <NUM> of rotor <NUM> in accordance with polarities of these magnetic fields. These forces cause rotor <NUM> to rotate around rotary shaft <NUM> in circumferential direction Z.

Described is a detailed configuration of stator <NUM> on which metal outer cover <NUM> and insulating film <NUM> are mounted in motor <NUM> configured as described above.

<FIG> is a cross-sectional view showing a main part of a positional relationship between coil assembly <NUM>, metal outer cover <NUM>, and insulating film <NUM> of the motor according to the exemplary embodiment of the present invention. <FIG> is a cross-sectional view showing a main part of motor <NUM> as a comparative example for comparison with the motor shown in <FIG>. <FIG> is an exploded perspective view showing coil assembly <NUM>, metal outer cover <NUM>, and insulating film <NUM> of the motor according to the exemplary embodiment of the present invention. <FIG> does not show mold resin portion <NUM> to present the configuration of coil assembly <NUM>. In reality, however, an outside of coil assembly <NUM> is covered with mold resin portion <NUM> as described above.

As shown in <FIG>, insulator <NUM> has bottom surface portion 13a mounted on stator core <NUM>, outer circumferential wall portion 13b forming a wall on an outer circumferential side, and inner circumferential wall portion 13c forming a wall on an inner circumferential side.

According to the configuration of the present exemplary embodiment, one insulator <NUM> is mounted on each of a pair of end surfaces of one tooth 11t. Specifically, insulators <NUM> are provided for the corresponding salient pole formed on stator core <NUM> on both sides of the salient pole in axial direction X. As described above, coil assembly <NUM> has a configuration including a plurality of insulators <NUM>. Bottom surface portion 13a of each of insulators <NUM> is constituted by a surface orthogonal to axial direction X. This surface formed in bottom surface portion 13a is mounted in close contact with each end surface of stator core <NUM> in axial direction X. Each of outer circumferential wall portion 13b and inner circumferential wall portion 13c is constituted by a wall surface extending in axial direction X. Outer circumferential wall portion 13b forms a wall erected on an outer circumferential side of a portion where coil <NUM> is formed, and regulates a coil position. As shown in <FIG>, inner circumferential wall portion 13c is located inside outer circumferential wall portion 13b in radial direction Y, and constitutes a wall erected on an inner circumferential side of the portion where coil <NUM> is formed, and regulates the coil position.

Bottom surface portion 13a of insulator <NUM> is mounted on each of both surfaces located at ends of tooth 11t in axial direction X. Winding wire 12w is wound via a pair of mounted insulators <NUM>. By performing this work, one coil <NUM> is formed for stator core <NUM>. Similar coils <NUM> are formed for respective teeth 11t, and respective coils <NUM> are electrically connected with each other according to a predetermined connection pattern to complete coil assembly <NUM> as shown in <FIG>.

Each of coils <NUM> of coil assembly <NUM> shown in <FIG> has coil ends 12a protruding toward both sides in axial direction X from stator core <NUM>. A portion of coil <NUM> other than coil ends 12a is housed in slot <NUM> of stator core <NUM> as shown in <FIG>. As shown in <FIG>, crossover wires 12b which join coils <NUM> to each other extend between respective teeth 11t on an outer circumference or the like of outer circumferential wall portion 13b of each of insulators <NUM> to electrically connect coils <NUM>.

If a safety protection function for preventing excessive currents flowing in coils <NUM> does not operate normally in a motor equipped with coil assembly <NUM>, excessive currents flow in coils <NUM>. In this case, coils <NUM> or crossover wires 12b generate heat and become extremely hot. As a result, layer short-circuiting as short-circuiting between winding wires 12w of coils <NUM> may be caused, or sparks may be generated by layer short-circuiting. Furthermore, there is a possibility that the generated sparks may ignite gas produced from insulators <NUM> or the like, and cause fire. In particular, coil ends 12a and crossover wires 12b as described above protrude from stator core <NUM>. Accordingly, the possibility of causing these problems is high.

According to the present exemplary embodiment, therefore, metal outer cover <NUM> which is a metal member as a non-combustion measure is arranged outside coil assembly <NUM> as shown in <FIG>. Specifically, metal outer cover <NUM> is provided outside mold resin portion <NUM> which covers the outside of coil assembly <NUM>. As shown in <FIG> and <FIG>, metal outer cover <NUM> is a metal cylinder having a substantially cup shape. According to the present exemplary embodiment, metal outer cover <NUM> is arranged so as to close the bottom of stator <NUM>, and surround the outside of the outer circumference of stator <NUM> with insulating film <NUM> interposed between metal outer cover <NUM> and stator <NUM>.

As shown in <FIG> and <FIG>, metal outer cover <NUM> is mounted on the outer surface of mold resin portion <NUM> of stator <NUM>. Metal outer cover <NUM> is mounted outside stator <NUM> on the side opposite to the output shaft.

Metal outer cover <NUM> is constituted by bottom surface portion 31a, curved surface portion 31b, and cylindrical portion 31c. Metal outer cover <NUM> has a hollow cup shape. Bottom surface portion 31a of metal outer cover <NUM> has a disc shape, and has opening <NUM> at a center of bottom surface portion 31a. Curved surface portion 31b is curved from bottom surface portion 31a in a curved shape at a substantially right angle. Cylindrical portion 31c extends in a cylindrical shape from curved surface portion 31b toward a tip, and a tip side of cylindrical portion 31c is opened. An inner diameter of cylindrical portion 31c is made substantially equal to an outer diameter of stator <NUM> such that cylindrical portion 31c can be fitted to an outer circumference of stator <NUM>.

According to the present exemplary embodiment, metal outer cover <NUM> in axial direction X is sized such that the tip of cylindrical portion 31c has a height sufficient for extending toward the tip in excess of coil end 12a on the output shaft side when metal outer cover <NUM> is mounted on stator <NUM> as shown in <FIG>. In other words, an attachment position of metal outer cover <NUM> is determined approximately at such a position that cylindrical portion 31c and both coil end 12a on the side opposite to the output shaft side and coil end 12a on the output shaft side completely face each other in radial direction Y via mold resin portion <NUM> when metal outer cover <NUM> is mounted on stator <NUM>.

As described above, metal outer cover <NUM> is arranged with respect to coil assembly <NUM> such that cylindrical portion 31c surrounds the outside of the outer circumference of stator core <NUM> shown in <FIG> with predetermined clearance Wa left from the outer circumference of stator core <NUM> in radial direction Y as shown in <FIG>. Metal outer cover <NUM> is mounted on stator <NUM> based on this positional relationship with respect to coil assembly <NUM>. Therefore, metal outer cover <NUM> surrounds insulators <NUM>, both coil ends 12a, and crossover wires 12b, and covers these members.

In other words, motor <NUM> includes metal outer cover <NUM> which is a metal member. Metal outer cover <NUM> is mounted on the outer surface of the mold resin so as to surround, at least in circumferential direction Z, both coil ends 12a protruding toward both sides in axial direction X.

Both coil ends 12a, insulators <NUM> and crossover wires 12b are covered with metal outer cover <NUM> as a non-combustion measure. Therefore, even if the above-mentioned problem, such as layer short-circuiting, causes fire which tries to spread to the outer circumferential side in radial direction Y from insulators <NUM> or crossover wires 12b, metal outer cover <NUM> cuts off the fire or smoke. Therefore, leakage of fire or smoke to the outside of motor <NUM> is avoidable.

When metal outer cover <NUM> is mounted outside stator <NUM> based on the above configuration, metal outer cover <NUM> is arranged close to coils <NUM> as shown in <FIG>. In addition, as described above, a maximum voltage as a withstanding voltage between the coils and the metal member, that is, a dielectric voltage is specified by the Electrical Appliance and Material Safety Act or the like to secure safety of the motor. As described above, the mold resin formed by molding includes voids and spaces not filled with resin. In this case, the dielectric voltage may decrease.

According to the configuration of the present exemplary embodiment, therefore, insulating film <NUM> is arranged between coils <NUM> and metal outer cover <NUM> in addition to the mold resin of mold resin portion <NUM> to secure electrical insulation between coils <NUM> and metal outer cover <NUM>. Specifically, insulating film <NUM> provided as above is interposed between the outer surface of mold resin portion <NUM> and the inner surface of metal outer cover <NUM>.

Insulating film <NUM> is an insulating sheet having a thin film shape. A material of insulating film <NUM> is not particularly limited. For example, polystyrene resin such as syndiotactic polystyrene (SPS), polyester resin such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), or the like can be used.

As shown in <FIG> and <FIG>, when clearance Wb between coils <NUM> and bottom surface portion 31a included in metal outer cover <NUM> is uniform, motor <NUM> can produce following effects. Specifically, according to motor <NUM> shown in <FIG>, mold resin portion <NUM> and insulating film <NUM> are arranged between coil <NUM> and bottom surface portion 31a. On the other hand, according to motor <NUM> in the comparative example shown in <FIG>, only mold resin portion <NUM> is arranged. Insulating film <NUM> is characterized by having higher electrical insulation than electrical insulation of the mold resin which forms mold resin portion <NUM>.

Accordingly, motor <NUM> has a single-layer structure including only mold resin portion <NUM> between coils <NUM> and bottom surface portion 31a. Mold resin portion <NUM> is a portion where voids may be formed. On the other hand, motor <NUM> has a two-layer structure including mold resin portion <NUM> and insulating film <NUM> which achieves high insulation between coils <NUM> and bottom surface portion 31a. Therefore, comparing motor <NUM> and motor <NUM>, motor <NUM> including insulating film <NUM> has a higher dielectric breakdown voltage than a dielectric breakdown voltage of motor <NUM>.

In other words, for securing an equivalent dielectric breakdown voltage, more reduction of clearance Wb, i.e., more thickness reduction is achievable by the structure including mold resin portion <NUM> and insulating film <NUM> shown in <FIG> than by the structure including only mold resin portion <NUM> shown in <FIG>. As described above, according to the configuration of the present exemplary embodiment, not only mold resin portion <NUM> but also insulating film <NUM> is arranged between coils <NUM> and bottom surface portion 31a included in metal outer cover <NUM> to increase the dielectric breakdown voltage.

As shown in <FIG>, insulating film <NUM> includes bottom surface portion 32a, curved surface portion 32b, and cylindrical portion 32c. Insulating film <NUM> has a hollow cup shape. Bottom surface portion 32a of insulating film <NUM> has a disc shape. Insulating film <NUM> has opening <NUM> at a center of insulating film <NUM>. Curved surface portion 32b is curved from bottom surface portion 32a in a curved shape at a substantially right angle. Cylindrical portion 32c extends in a cylindrical shape from curved surface portion 32b toward a tip, and the tip side of cylindrical portion 32c is opened.

An inner diameter of cylindrical portion 32c is made substantially equal to the outer diameter of stator <NUM> such that cylindrical portion 32c can be fitted to the outer circumference of stator <NUM>.

As shown in <FIG>, step portion <NUM> having depth ts is formed in the outer surface of mold resin portion <NUM> at a portion where insulating film <NUM> is attached. Depth ts of step portion <NUM> is substantially equal to a thickness of insulating film <NUM>. A tip of insulating film <NUM> on the side of cylindrical portion 32c is attached so as to come into contact with an end of step portion <NUM> located in axial direction X. A tip of insulating film <NUM> on the side of opening <NUM> is attached so as to come into contact with an end of step portion <NUM> located in radial direction Y. Specifically, the outer surface of stator <NUM> including insulating film <NUM> becomes a uniform surface by attaching insulating film <NUM>, which has a thickness substantially equal to depth ts of step portion <NUM>, to step portion <NUM> in such a manner as to be fitted to step portion <NUM> on the outer surface of mold resin portion <NUM>. Therefore, metal outer cover <NUM> is closely attached to mold resin portion <NUM> with insulating film <NUM> interposed between metal outer cover <NUM> and mold resin portion <NUM>.

By providing step portion <NUM>, insulating film <NUM> can be easily mounted on mold resin portion <NUM>, and positional displacement of insulating film <NUM> can be prevented.

According to the present exemplary embodiment, therefore, motor <NUM> which covers stator <NUM> with mold resin is capable of securing sufficient electrical insulation, and also preventing leakage of fire to the outside of the motor even if excessive currents flow in coils <NUM> wound around stator core <NUM>.

As apparent from the above description, motor <NUM> of the present exemplary embodiment includes metal outer cover <NUM> as a non-combustion measure. Metal outer cover <NUM> described above is fitted to the outer circumference of stator <NUM> in the manner described above. In this case, metal outer cover <NUM> is arranged so as to cover insulators <NUM>, coil ends 12a, and crossover wires 12b. Therefore, metal outer cover <NUM> can cut off fire and smoke generated inside motor <NUM>.

Moreover, according to the configuration of the present exemplary embodiment, insulators <NUM> and coil ends 12a are entirely covered with mold resin portion <NUM> with only the inner circumferential surface of each tooth 11t exposed. Therefore, sufficient holding strength of coil assembly <NUM> in stator <NUM> is secured while achieving the fire protection measure described above.

Furthermore, according to the present exemplary embodiment, insulating film <NUM> is arranged between mold resin portion <NUM> and metal outer cover <NUM>. In this case, insulating characteristics improve only by interposing insulating film <NUM> between coils <NUM> and metal outer cover <NUM>. Therefore, improvement is easily achievable without a necessity of a structural change or the like. Furthermore, electrical insulation improves by interposing insulating film <NUM> as a thin film. Therefore, the thickness of mold resin portion <NUM> can be reduced while securing electrical insulation. As described above, according to the present exemplary embodiment, reduction of the thickness of mold resin portion <NUM> and therefore miniaturization of the motor are achievable while maintaining sufficient electrical insulation.

As described above, motor <NUM> which covers stator <NUM> with mold resin portion <NUM> is capable of securing electrical insulation, and also preventing leakage of fire to the outside of the motor even if excessive currents flow in coils <NUM> wound around stator core <NUM>.

As described above, the molded motor of the present exemplary embodiment includes rotor <NUM>, stator <NUM> facing rotor <NUM>, bearings <NUM> on which rotor <NUM> is rotatably supported, mold resin portion <NUM> covering stator <NUM> with mold resin, a metal member corresponding to metal outer cover <NUM> and mounted on the outer surface of mold resin portion <NUM>, and an insulating material corresponding to insulating film <NUM> and located between mold resin portion <NUM> and the metal member. Rotor <NUM> has rotary shaft <NUM> that extends in axial direction X, and rotor core <NUM> that holds permanent magnets <NUM> and is fixed to rotary shaft <NUM>. Stator <NUM> includes stator core <NUM> on which a plurality of salient poles corresponding to a plurality of teeth 11t are arranged in a circumferential direction, and a plurality of coils <NUM> each wound via insulator <NUM> around corresponding one of the salient poles of stator core <NUM>. The metal member includes cylindrical portion 31c having a cylindrical shape, and bottom surface portion 31a that forms a bottom surface of cylindrical portion 31c. At least a part of a surface of the insulating material is arranged at a portion facing the plurality of coils <NUM> arranged in the circumferential direction.

Accordingly, the molded motor to be provided is capable of reducing an increase in a size of a motor external shape while securing electrical insulation, and capable of preventing leakage of fire to the outside of the motor even if excessive currents flow in coils wound around a stator core.

In addition, each of the plurality of coils <NUM> includes coil ends 12a that protrude from stator core <NUM> toward both sides in axial direction X. Cylindrical portion 31c is located at a portion included in the outer circumferential surface of mold resin portion <NUM> and facing at least coil ends 12a protruding toward both the sides.

Moreover, the insulating material corresponding to insulating film <NUM> may have a cup shape having a hole formed in a bottom surface portion of the insulating material, and may be interposed between an inner surface of the metal member corresponding to metal outer cover <NUM> and the outer surface of mold resin portion <NUM>.

<FIG> is a half cross-sectional view of motor <NUM> according to a non-claimed example. <FIG> is a cross-sectional plan view as viewed from arrow <NUM>-<NUM> of <FIG>. <FIG> is a cross-sectional view showing a positional relationship between coil assembly <NUM>, metal inner cover <NUM>, metal outer cover <NUM>, and insulating film <NUM> of the motor according to the non-claimed example.

As shown in <FIG>, motor <NUM> of the present non-claimed example is a motor similar to motor <NUM> of the exemplary embodiment. In comparison with motor <NUM>, motor <NUM> includes, in addition to metal outer cover <NUM>, metal inner cover <NUM> as an inner metal member which is located inside mold resin portion <NUM> as a mold resin. Specifically, as shown in <FIG>, motor <NUM> has stator <NUM> which includes coil assembly <NUM> on which metal inner cover <NUM> is mounted, and mold resin portion <NUM> integrating these members. Metal outer cover <NUM> has a cup shape similarly to metal outer cover <NUM> of the exemplary embodiment. Metal outer cover <NUM> has a shorter length in axial direction X than the length of metal outer cover <NUM> of the exemplary embodiment. Other configurations and operations are similar to the corresponding configurations and operations of the exemplary embodiment. Components identical to corresponding components of the exemplary embodiment are given identical reference numerals, and the description of the exemplary embodiment is referred to for similar portions.

If a safety protection function for preventing excessive currents flowing in coils <NUM> does not operate normally in a motor equipped with coil assembly <NUM> herein, excessive currents flow in coils <NUM>. In this case, coils <NUM> or crossover wires 12b generate heat and become extremely hot. As a result, layer short-circuiting as short-circuiting between winding wires of coils <NUM> may be caused, or sparks may be generated by layer short-circuiting. Furthermore, there is a possibility that the generated sparks may ignite gas produced from insulators <NUM> or the like, and cause fire. In particular, coil ends 12a and crossover wires 12b as described above protrude from stator core <NUM>. Accordingly, the possibility of causing these problems is high.

Therefore, similarly to the exemplary embodiment, metal outer cover <NUM> which is a metal member as a non-combustion measure is arranged outside coil assembly <NUM> as shown in <FIG>. Moreover, metal inner cover <NUM>, which is a metal member as a non-combustion measure, is arranged. Coil assembly <NUM> including metal inner cover <NUM> as an inner metal member is provided inside the mold resin.

Specifically, as shown in <FIG>, each of the plurality of coils <NUM> of motor <NUM> includes coil ends 12a protruding from stator core <NUM> toward both sides in axial direction X. Cylindrical portion 41c included in metal outer cover <NUM> as the metal member is located on the outer circumferential surface of mold resin portion <NUM> at least at a position facing one of coil ends 12a (12aB).

Motor <NUM> further includes metal inner cover <NUM> as a cylindrical inner metal member. Metal inner cover <NUM> is located inside mold resin portion <NUM> at a position facing at least the other of coil ends 12a (12aT).

According to motor <NUM>, metal outer cover <NUM> as the metal member and metal inner cover <NUM> as the inner metal member each include overlapping portion 41e extending in axial direction X. Metal outer cover <NUM> and metal inner cover <NUM> are arranged apart from each other in a direction intersecting axial direction X, that is, in radial direction Y.

Metal inner cover <NUM> as the inner metal member is provided inside mold resin portion <NUM> as the mold resin. Metal inner cover <NUM> has large diameter portion 43b and small diameter portion 43a.

Large diameter portion 43b faces one coil end 12aT of coil ends 12a protruding toward both the end sides in axial direction X in such a manner as to surround one coil end 12aT in circumferential direction Z.

Small diameter portion 43a has an inner diameter smaller than an inner diameter of large diameter portion 43b. Small diameter portion 43a faces stator core <NUM> in such a manner as to surround the outer circumferential surface of stator core <NUM> in circumferential direction Z.

Metal outer cover <NUM> as the metal member is mounted on the outer circumferential surface of mold resin portion <NUM>.

Metal outer cover <NUM> is mounted on the outer surface of mold resin portion <NUM> as the mold resin so as to surround, at least in circumferential direction Z, other coil end 12aT of coil ends 12a protruding toward both the sides in axial direction X.

As shown in <FIG> and <FIG>, metal inner cover <NUM> is a metal cylinder having a substantially cylindrical shape and opened on both sides. According to the present non-claimed example, metal inner cover <NUM> is arranged so as to surround outside the outer circumference of coil assembly <NUM> with a predetermined clearance left in radial direction Y from the outer circumference of coil assembly <NUM>.

As shown in <FIG>, metal inner cover <NUM> has small diameter portion 43a, and large diameter portion 43b having a diameter larger than a diameter of small diameter portion 43a.

Large diameter portion 43b faces one coil end 12a of the coil ends protruding toward both the end sides in axial direction X in such a manner as to surround one coil end 12a in circumferential direction Z. Small diameter portion 43a faces stator core <NUM> in such a manner as to surround the outer circumferential surface of stator core <NUM> in circumferential direction Z.

The inner diameter of small diameter portion 43a is made substantially equal to an outer diameter of stator core <NUM> such that small diameter portion 43a can be fitted to the outer circumference of stator core <NUM>. Specifically, as shown in <FIG>, a plurality of protrusions 11p are formed on the outer circumferential surface of stator core <NUM> at equal intervals in circumferential direction Z. A size of the inner diameter of small diameter portion 43a of metal inner cover <NUM> is determined such that an inner circumferential surface of small diameter portion 43a contacts each tip of protrusions 11p.

As shown in <FIG>, a size of small diameter portion 43a in axial direction X is also substantially equal to a size of stator core <NUM> in axial direction X. In this case, metal inner cover <NUM> is fitted to coil assembly <NUM> such that the tips of protrusions 11p formed on stator core <NUM> and the inner circumferential surface of small diameter portion 43a of metal inner cover <NUM> are joined to each other. Therefore, metal inner cover <NUM> is simply and temporarily fixed to coil assembly <NUM>. As shown in <FIG>, in the temporarily fixed state, space <NUM> as a narrow space exists between the outer circumferential surface of stator core <NUM> and the inner circumferential surface of small diameter portion 43a except for a portion where respective protrusions 11p are arranged. Space <NUM> is also filled with resin during molding.

As shown in <FIG>, a size of large diameter portion 43b in axial direction X is larger than each size of coil ends 12a in axial direction X. Large diameter portion 43b is provided on metal inner cover <NUM> only on one side of small diameter portion 43a in axial direction X. By attaching metal inner cover <NUM> to coil assembly <NUM>, large diameter portion 43b of metal inner cover <NUM> is arranged so as to surround coil ends 12a and crossover wires 12b on one side in axial direction X.

Note that insulators <NUM>, coil ends 12a, crossover wires 12b, and the like are also separately shown as follows to clarify the arrangement of metal inner cover <NUM> in <FIG>. Insulator 13B, coil end 12aB, and crossover wire 12bB are arranged on one side of stator core <NUM> in axial direction X in <FIG>. Similarly, insulator 13T, coil end 12aT, and crossover wire 12bT are arranged on the other side opposite to the one side in axial direction X.

Accordingly, as shown in <FIG>, metal inner cover <NUM> is arranged such that large diameter portion 43b of metal inner cover <NUM> surrounds insulator 13T, coil end 12aT, and crossover wire 12bT. On the other hand, insulator 13B, coil end 12aB, and crossover wire 12bB are not surrounded by metal inner cover <NUM>.

In this manner, large diameter portion 43b of metal inner cover <NUM> as a non-combustion measure is arranged on the outer circumferential side of coil end 12aT, outer circumferential wall portion 13b of insulator 13T, and crossover wire 12bT. Therefore, even if a problem such as layer short-circuiting described above causes fire coming from coils <NUM> and trying to spread to the outer circumferential side of insulator 13T and crossover wire 12bT in radial direction Y, large diameter portion 43b of metal inner cover <NUM> cuts off the fire and smoke. Therefore, leakage of fire and smoke to the outside of motor <NUM> is avoidable.

As shown in <FIG>, motor <NUM> has a configuration including metal outer cover <NUM> as a non-combustion measure similarly to the exemplary embodiment, in addition to the fire prevention measure which arranges metal inner cover <NUM> in stator <NUM>. Moreover, motor <NUM> is configured such that insulating film <NUM> is interposed between the outer surface of mold resin portion <NUM> and the inner surface of metal outer cover <NUM> to secure the dielectric voltage.

As shown in <FIG>, metal outer cover <NUM> is constituted by bottom surface portion 41a, curved surface portion 41b, and cylindrical portion 41c similarly to the exemplary embodiment. Metal outer cover <NUM> has a hollow cup shape. Bottom surface portion 41a of metal outer cover <NUM> has a disc shape, and has opening <NUM> at a center of bottom surface portion 41a. Curved surface portion 41b is curved from bottom surface portion 41a in a curved shape at a substantially right angle. Cylindrical portion 41c extends in a cylindrical shape from curved surface portion 41b toward a tip, and a tip side of cylindrical portion 41c is opened. An inner diameter of cylindrical portion 41c is made substantially equal to the outer diameter of stator <NUM> such that cylindrical portion 41c can be fitted to the outer circumference of stator <NUM>.

As shown in <FIG> and <FIG>, metal outer cover <NUM> is mounted on the outer surface of mold resin portion <NUM> of stator <NUM>. Metal outer cover <NUM> is mounted outside stator <NUM> on the side opposite to the output shaft. Metal outer cover <NUM> mounted in this manner is arranged at a position on the side opposite to large diameter portion 43b of metal inner cover <NUM> with respect to stator core <NUM> in axial direction X. In this case, large diameter portion 43b of metal inner cover <NUM> is provided for coil end 12aT and the like on the output shaft side, while metal outer cover <NUM> is arranged for coil end 12aB and the like on the side opposite to output shaft. In this manner, respective non-combustion measures are achieved. Large diameter portion 43b is provided to take the non-combustion measure on the output shaft side. Accordingly, a length of metal outer cover <NUM> in axial direction X is set to a size sufficient for surrounding coil end 12aB on the side opposite to the output shaft, that is, for producing overlapping portion 41e between cylindrical portion 41c and metal inner cover <NUM> in axial direction X. In other words, an attachment position of metal outer cover <NUM> is set to a position sufficient for producing overlapping portion 41e between cylindrical portion 41c and stator core <NUM> in axial direction X when metal outer cover <NUM> is mounted on stator <NUM>. <FIG> shows a specific example where overlapping portion 41e has size Wd. In this manner, the length of metal outer cover <NUM> in axial direction X is longer than the size of coil end 12aB in axial direction X, and is shorter than the length of metal outer cover <NUM> of the exemplary embodiment.

As described above, motor <NUM> of the present non-claimed exampleincludes metal inner cover <NUM> and metal outer cover <NUM> as non-combustion measures.

When molding is performed in a state where metal inner cover <NUM> is mounted on the side surface of stator core <NUM>, stator <NUM> which includes mold resin portion <NUM> integrating these members is produced. On the output shaft side of stator <NUM>, large diameter portion 43b of metal inner cover <NUM> is arranged so as to surround insulator 13T, coil end 12aT, and crossover wire 12bT. Therefore, on the output shaft side, large diameter portion 43b of metal inner cover <NUM> can cut off fire and smoke generated inside motor <NUM>.

Moreover, according to the present non-claimed example, metal outer cover <NUM> is fitted to the outer circumference of stator <NUM> in the manner described above. In this case, metal outer cover <NUM> is arranged so as to cover insulator 13B, coil end 12aB, and crossover wire 12bB on the side opposite to the output shaft. Therefore, on the side opposite to the output shaft, metal outer cover <NUM> can cut off fire and smoke generated inside motor <NUM>.

Moreover, according to the configuration of the present non-claimed example, a whole of insulators <NUM> and coil ends 12a as well as a whole of metal inner cover <NUM> are covered with mold resin portion <NUM> with only the inner circumferential surface of each tooth 11t exposed. Therefore, sufficient holding strength of coil assembly <NUM> in stator <NUM> is secured while taking the fire protection measure described above.

Furthermore, according to the present non-claimed example, insulating film <NUM> as an insulating material is similarly arranged between mold resin portion <NUM> and metal outer cover <NUM>. In this case, insulating characteristics easily improve only by interposing insulating film <NUM> between coils <NUM> and metal outer cover <NUM>. Furthermore, reduction of the thickness of mold resin portion <NUM> is achievable along with sufficient electrical insulation by interposing insulating film <NUM> as a thin film. Accordingly, reduction of the thickness of mold resin portion <NUM> and miniaturization of the motor are also achievable while maintaining sufficient electrical insulation.

In addition, each of the plurality of coils <NUM> may include coil ends 12a that protrude from stator core <NUM> toward both sides in axial direction X. Cylindrical portion 41c may be located at a portion included in the outer circumferential surface of mold resin portion <NUM> and facing at least one of coil ends 12a protruding toward both the sides.

Moreover, the molded motor of the present non-claimed examplemay further include an inner metal member corresponding to metal inner cover <NUM> having a cylindrical shape. The inner metal member may be located inside mold resin portion <NUM> and at a portion facing at least the other of coil ends 12a protruding toward both the sides.

Furthermore, each of the metal member corresponding to metal outer cover <NUM> and the inner metal member corresponding to metal inner cover <NUM> may include overlapping portion 41e extending in axial direction X, and may be separated from each other in a direction intersecting axial direction X.

In addition, the inner metal member corresponding metal inner cover <NUM> may be provided inside mold resin portion <NUM>. The inner metal member may include: large diameter portion 43b that faces one coil end 12aT of coil ends 12a protruding toward both the sides in axial direction X to surround one coil end 12aT in circumferential direction Z; and small diameter portion 43a that has an inner diameter smaller than an inner diameter of large diameter portion 43b, and faces stator core <NUM> to surround the outer circumferential surface of stator core <NUM> in circumferential direction Z.

Moreover, a metal member corresponding to metal outer cover <NUM> may be mounted on the outer circumferential surface of mold resin portion <NUM>, and may be mounted on the outer surface of the mold resin so as to surround, at least in circumferential direction Z, other coil end 12aT of coil ends 12a protruding toward both the sides in axial direction X.

Other non-claimed modifications are hereinafter described. Note that characteristic main parts of the non-claimed modifications are chiefly described below.

<FIG> is an exploded perspective view showing stator 10a, insulating film <NUM>, and metal outer cover <NUM> of a motor in non-claimed Modification <NUM> of the present invention. <FIG> shows stator 10a covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the motor of present non-claimed Modification <NUM>. Other configurations are similar to corresponding configurations of the exemplary embodiment and the non-claimed example.

As shown in <FIG>, insulating film <NUM> as an insulating material of the motor of non-claimed Modification <NUM> has a disc shape having a hole at a center of insulating film <NUM>.

Insulating film <NUM> is interposed between an inner surface of bottom surface portion 31a included in metal outer cover <NUM> as a metal member, and an outer surface of mold resin portion <NUM>.

According to the exemplary embodiment and the non-claimed example, for example, insulating film <NUM> having a cup shape has been described by way of example as shown in <FIG>. However, as shown in non-claimed Modification <NUM> in <FIG>, insulating film <NUM> having a disc-shape and a hole at the center is adoptable as the insulating material. Accordingly, insulating film <NUM> is a disc having opening <NUM> as a hole at a center of a plane.

Moreover, as shown in <FIG>, step portion <NUM> is formed in an end surface of stator 10a in axial direction X at a portion where stator 10a and insulating film <NUM> are in contact with each other. When a depth of step portion <NUM> and a thickness of insulating film <NUM> are substantially equal, an outer surface of stator 10a to which insulating film <NUM> is attached becomes uniform. In this configuration, stator 10a and bottom surface portion 31a included in metal outer cover <NUM> can come into close contact with each other even when insulating film <NUM> is interposed.

As described above, an insulating material corresponding to insulating film <NUM> in the present non-claimed modification may have a disc shape having a hole formed at the center. The insulating material may be interposed between the inner surface of bottom surface portion 31a and the outer surface of mold resin portion <NUM>.

<FIG> is an exploded perspective view showing stator 10b, insulating film <NUM>, and metal outer cover <NUM> of a motor in non-claimed Modification <NUM> of the present invention. <FIG> shows stator 10b covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the motor of present non-claimed Modification <NUM>. Other configurations are similar to corresponding configurations of exemplary embodiment and the non-claimed example.

As shown in <FIG>, insulating film <NUM> as an insulating material of the motor of non-claimed Modification <NUM> has a belt shape.

Insulating film <NUM> is interposed between an inner surface of cylindrical portion 31c included in metal outer cover <NUM> as a metal member, and an outer surface of mold resin portion <NUM>.

According to the exemplary embodiment and the non-claimed example, for example, insulating film <NUM> having a cup shape has been described by way of example as shown in <FIG>. However, as shown in non-claimed Modification <NUM> in <FIG>, insulating film <NUM> having a belt shape is adoptable as the insulating material. Specifically, the insulating material may be produced by forming belt-shaped insulating film <NUM> into a ring shape.

Moreover, as shown in <FIG>, step portion <NUM> is formed in a side surface of stator 10b in radial direction Y at a portion where stator 10b and insulating film <NUM> are in contact with each other. When a depth of step portion <NUM> and a thickness of insulating film <NUM> are substantially equal, an outer surface of stator 10b to which insulating film <NUM> is attached becomes uniform. In this configuration, stator 10b and cylindrical portion 31c included in metal outer cover <NUM> come into close contact with each other even when insulating film <NUM> is interposed.

As apparent from the description of non-claimed Modifications <NUM> and <NUM>, the shapes of insulating films <NUM>, <NUM> are not particularly limited. In short, it is sufficient if insulating films <NUM>, <NUM> are arranged between coils <NUM> and metal outer cover <NUM> inside stator 10a, 10b at such positions the requiring sufficient dielectric voltage in a state where coils <NUM> are close to metal outer cover <NUM>.

As described above, an insulating material corresponding to insulating film <NUM> in the present non-claimed modification may have a belt shape. The insulating material may be interposed between the inner surface of cylindrical portion 31c and the outer surface of mold resin portion <NUM>.

<FIG> is an exploded perspective view showing stator 10c, insulating film <NUM>, and metal outer cover <NUM> of a motor in non-claimed Modification <NUM> of the present invention. <FIG> shows stator 10c covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the motor of present non-claimed Modification <NUM>.

As shown in <FIG>, insulating film <NUM> as an insulating material of the motor of non-claimed Modification <NUM> has cut <NUM>. Mold resin portion <NUM> has protrusion <NUM> protruding in alignment with cut <NUM>.

In non-claimed Modification <NUM>, one cut <NUM>, which is a film cut, is provided in cylindrical portion 322c included in insulating film <NUM> having a cup shape. Mold resin portion <NUM> includes protrusion <NUM> having a linear shape. Cut <NUM> is fitted to protrusion <NUM>. Other configurations are similar to corresponding configurations of the exemplary embodiment or the non-claimed example.

As shown in <FIG>, these changes may be made to insulating film <NUM> or mold resin portion <NUM> of stator <NUM> shown in <FIG>, for example. According to the motor of non-claimed Modification <NUM> obtained in this manner, insulating film <NUM> can be easily mounted, and displacement of insulating film <NUM> can be prevented by the changes of addition of cut <NUM> and protrusion <NUM>. Therefore, the motor obtained by the configuration of non-claimed Modification <NUM> is capable of preventing leakage of fire to the outside of the motor, securing electrical insulation, and improving workability.

Furthermore, step portion <NUM> may be provided for stator 10c shown in <FIG> similarly to non-claimed Modification <NUM>. <FIG> shows a specific example.

<FIG> is an exploded perspective view showing stator 10d, insulating film <NUM>, and metal outer cover <NUM> of a different motor in non-claimed Modification <NUM> of the present invention. As shown in <FIG>, mold resin portion <NUM> of the different motor of non-claimed Modification <NUM> has step portion <NUM>. Step portion <NUM> houses insulating film <NUM> as an insulating material at a portion where mold resin portion <NUM> and metal outer cover <NUM> as a metal member face each other.

<FIG> shows stator 10d covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the different motor of non-claimed Modification <NUM>. According to stator 10d of the different motor, protrusion <NUM> is provided on step portion <NUM> in mold resin portion <NUM>.

The different motor shown in <FIG> offers following effects in addition to the effects of non-claimed Modification <NUM> shown in <FIG>. Step portion <NUM> is formed in a side surface of stator 10d in radial direction Y at a portion where stator 10d and insulating film <NUM> are in contact with each other. When a depth of step portion <NUM> and a thickness of insulating film <NUM> are substantially equal, an outer surface of stator 10d to which insulating film <NUM> is attached becomes uniform. In this configuration, stator 10d and cylindrical portion 31c included in metal outer cover <NUM> come into close contact with each other even when insulating film <NUM> is interposed.

A plurality of cuts <NUM> and a plurality of protrusions <NUM> may be provided.

As described above, in the present non-claimed modification, an insulating material corresponding to insulating film <NUM> may have cut <NUM>, and mold resin portion <NUM> may have protrusion <NUM> protruding in alignment with cut <NUM>.

Moreover, mold resin portion <NUM> may have a step portion for housing an insulating material corresponding to insulating film <NUM> at a portion where mold resin portion <NUM> and a metal member corresponding to metal outer cover <NUM> face each other.

<FIG> is an exploded perspective view showing stator 10e, insulating film <NUM>, and metal outer cover <NUM> of a motor in non-claimed Modification <NUM> of the present invention. <FIG> shows stator 10e covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the motor of non-claimed Modification <NUM>. According to non-claimed Modification <NUM>, one cut <NUM> is formed by cutting a rectangular portion from an outer circumference of insulating film <NUM> which has a disc shape having a hole at a center of insulating film <NUM>. Protrusion <NUM> having a rectangular shape and corresponding to cut <NUM> is formed on mold resin portion <NUM> at step portion <NUM> provided in an end surface in axial direction X. Other configurations are similar to corresponding configurations of the exemplary embodiment or the non-claimed example, or non-claimed Modification <NUM>.

As shown in <FIG>, these changes may be given to insulating film <NUM> having a disc shape and described in non-claimed Modification <NUM>, or mold resin portion <NUM> of stator <NUM> shown in <FIG>. According to the motor of non-claimed Modification <NUM> obtained in this manner, insulating film <NUM> can be easily mounted, and positional displacement of insulating film <NUM> can be prevented by adding cut <NUM> and protrusion <NUM>. Therefore, the motor obtained by the configuration of non-claimed Modification <NUM> is capable of preventing leakage of fire to the outside of the motor, securing electrical insulation, and improving workability.

The shapes of cut <NUM> and protrusion <NUM>, which are characteristics of non-claimed Modification <NUM>, are not limited to the rectangular shapes described above. For example, each of cut <NUM> and protrusion <NUM> having other shapes such as a triangle, a trapezoid, a semicircle, and a cross can offer similar effects.

Moreover, a plurality of cuts <NUM> and a plurality of protrusions <NUM> may be provided.

<FIG> is an exploded perspective view showing stator 10f, insulating film <NUM>, and metal outer cover <NUM> of a motor in non-claimed Modification <NUM> of the present invention. <FIG> shows stator 10f covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in the motor of non-claimed Modification <NUM>. According to non-claimed Modification <NUM>, insulating film <NUM> having a disc shape includes three holes <NUM> penetrating a front and a back of insulating film <NUM>. Three protrusions <NUM> corresponding to holes <NUM> are formed on mold resin portion <NUM> at step portion <NUM> provided in an end surface in axial direction X. Other configurations are similar to corresponding configurations of the exemplary embodiment or the non-claimed example, or non-claimed Modification <NUM>.

As shown in <FIG>, for example, these changes may be given to insulating film <NUM> having a disc shape and described in non-claimed Modification <NUM>, and mold resin portion <NUM> of stator <NUM> shown in <FIG>. According to the motor of non-claimed Modification <NUM> obtained in this manner, insulating film <NUM> can be easily mounted, and positional displacement of insulating film <NUM> can be prevented by the changes of addition of holes <NUM> and protrusions <NUM>. Therefore, the motor obtained by the configuration of non-claimed Modification <NUM> is capable of preventing leakage of fire to the outside of the motor, securing electrical insulation, and improving workability.

The shapes of holes <NUM> and protrusions <NUM>, which are characteristics of non-claimed Modification <NUM>, are not particularly limited. For example, holes <NUM> and protrusions <NUM> each having a cylindrical shape, a polygonal pillar shape typified by a triangular pillar and a quadrangular pillar, or a cylindrical shape or a pyramid shape having a different cross-sectional shape such as a semicircular shape and a cross shape can offer similar operations and effects.

Moreover, each of numbers of holes <NUM> and protrusions <NUM> to be provided may be a different number.

<FIG> is a half cross-sectional view of motor <NUM> according to non-claimed Modification <NUM> of the present invention. <FIG> shows an overall outline of motor <NUM> of non-claimed Modification <NUM>. Details are described with reference to <FIG> and <FIG> each showing an enlarged main part. <FIG> is a half cross-sectional view showing motor <NUM> as a comparative example for comparison with motor <NUM> shown in <FIG>.

<FIG> is a cross-sectional view showing a main part of a positional relationship between coil assembly <NUM>, metal outer cover <NUM>, and insulating film <NUM> of motor <NUM> according to non-claimed Modification <NUM> of the present invention. <FIG> is a cross-sectional view showing a main part of a different positional relationship between coil assembly <NUM>, metal outer cover <NUM>, and insulating film <NUM> of motor <NUM> according to non-claimed Modification <NUM> of the present invention.

As shown in <FIG> and <FIG>, mold resin portion <NUM> of motor <NUM> of non-claimed Modification <NUM> has step portion <NUM>. Step portion <NUM> houses insulating film <NUM> as an insulating material and metal outer cover <NUM> at a portion where mold resin portion <NUM> and metal outer cover <NUM> as a metal member face each other.

The outer surface of metal outer cover <NUM> as a metal member, and an outer surface of mold resin portion <NUM> are located on an identical plane.

<FIG> shows stator 40a covered with mold resin portion <NUM>, insulating film <NUM> having opening <NUM>, and metal outer cover <NUM> in motor <NUM> of non-claimed Modification <NUM>.

In non-claimed Modification <NUM>, step portion <NUM> formed on mold resin portion <NUM> is constituted by a plurality of steps. Specifically, step portion <NUM> is constituted by first step portion 419sa and second step portion 419sb sequentially located in axial direction X or radial direction Y from a center of stator 40a. A depth of first step portion 419sa is substantially equal to thickness ts of insulating film <NUM>. A depth of second step portion 419sb is substantially equal to thickness ts1 of metal outer cover <NUM>.

In other words, mold resin portion <NUM> includes step portion <NUM> having a depth equivalent to a sum of thicknesses of metal outer cover <NUM> and insulating film <NUM>.

According to motor <NUM> of non-claimed Modification <NUM>, a length of cylindrical portion 41c included in metal outer cover <NUM> is larger than a length of cylindrical portion 32c included in insulating film <NUM> in axial direction X. In this case, mold resin portion <NUM> and metal outer cover <NUM> of motor <NUM> are in direct contact with each other. Therefore, metal outer cover <NUM> is firmly fixed to mold resin portion <NUM> by press-fitting metal outer cover <NUM> into mold resin portion <NUM>.

Other configurations are similar to corresponding configurations of the exemplary embodiment or the non-claimed example.

In this configuration, the outer surface of metal outer cover <NUM> as the metal member and an outer surface of mold resin portion <NUM> are located on an identical plane in axial direction X or radial direction Y in motor <NUM>.

Specifically, mold resin portion <NUM> of motor <NUM> has step portion <NUM> at a portion where mold resin portion <NUM> faces insulating film <NUM> and metal outer cover <NUM>. Step portion <NUM> has a depth corresponding to a sum of insulating film <NUM> and metal outer cover <NUM> (ts + ts1).

Therefore, according to stator 40a included in motor <NUM>, size Wa1 of a portion of only mold resin portion <NUM> in radial direction Y is equal to size Wa2 of a portion of mold resin portion <NUM> where insulating film <NUM> and metal outer cover <NUM> are attached in radial direction Y. Alternatively, according to stator 40a included in motor <NUM>, size Wb1 of a portion of only mold resin portion <NUM> in axial direction X is equal to size Wb2 of a portion of mold resin portion <NUM> where insulating film <NUM> and metal outer cover <NUM> are attached in axial direction X.

Moreover, motor <NUM> including insulating film <NUM> is capable of securing the dielectric voltage corresponding to use applications. Motor <NUM> including metal outer cover <NUM> is capable of preventing leakage of fire to the outside of the motor even if sparks or the like are generated in motor <NUM> for some reasons.

As a comparative example of non-claimed Modification <NUM>, motor <NUM> conventionally incorporated in an electric device or the like is shown in <FIG> herein.

As shown in <FIG>, motor <NUM> has body length Wx in axial direction X, and length Wy in radial direction Y.

On the other hand, as shown in <FIG>, motor <NUM> to which the modification described in present non-claimed Modification <NUM> is added improves electrical insulation by interposing insulating film <NUM> as a thin film. Therefore, motor <NUM> can reduce the thickness of mold resin portion <NUM> while securing electrical insulation. In other words, motor <NUM> of present non-claimed Modification <NUM> is capable of achieving reduction of the thickness of mold resin portion <NUM> and miniaturization of the motor while maintaining sufficient electrical insulation. Therefore, it is possible to produce motor <NUM> having body length Wx in axial direction X, and length Wy in radial direction Y.

In other words, it is possible to produce motor <NUM> of present non-claimed Modification <NUM> having an external size equivalent to the size of the motor conventionally incorporated in electric devices and the like.

Accordingly, motor <NUM> is capable of achieving improvement of fire preventive performance of the electric device where conventional motor <NUM> is incorporated in addition to the operations and effects of the exemplary embodiment or the non-claimed example and the like without adding a change to the electric device.

A case where a PET film is used as insulating film <NUM> is described with reference to the drawings.

<FIG> is an enlarged view of a main part of motor <NUM> shown in <FIG>. <FIG> is an enlarged view of a main part of motor <NUM> as a comparative example for comparison with motor <NUM> shown in <FIG>.

The comparative example shown in <FIG> is described. As shown in <FIG>, motor <NUM> includes metal outer cover <NUM> provided by the inventors of the present application as a so-called non-combustion measure for a conventional motor covered with mold resin.

Specifically, thickness Wa3 of mold resin portion <NUM>, which is a distance between crossover wires 12b and an outer surface of the motor, is <NUM>. The thickness of mold resin portion <NUM> is an important index for securing an insulation distance from crossover wires 12b. Specifically, mold resin portion <NUM> is required to have a predetermined thickness to secure a predetermined insulation distance in a creepage distance from crossover wires 12b to metal outer cover <NUM>. Metal outer cover <NUM> having a thickness ts1 = <NUM> is attached to the outer surface of motor <NUM>. Therefore, size Wa4 from crossover wires 12b to the outer surface of metal outer cover <NUM> in motor <NUM> is <NUM>.

In other words, the external size of the motor including the non-combustion measure initially performed for the conventional motor by the inventors of the present application increases by a thickness of metal outer cover <NUM> in radial direction Y, i.e., <NUM> (<NUM> × <NUM> directions).

On the other hand, as shown in <FIG>, motor <NUM> described in non-claimed Modification <NUM> uses the PET film having thickness ts = <NUM> as insulating film <NUM>. For example, Teijin (registered trademark) Tetoron (registered trademark) UF is adoptable as the PET film. Teijin Tetoron UF herein satisfies VTM-<NUM> of the international standard UL94 of flame-retardant grade, and is therefore preferable from a viewpoint of the non-combustion measure, which is the main object of the present invention.

When insulating film <NUM> is used, motor <NUM> may be configured as follows. Thickness Wa5 of mold resin portion <NUM> from crossover wires 12b to insulating film <NUM> is <NUM>. Thickness ts1 of metal outer cover <NUM> attached to the outer surface of motor <NUM> is <NUM>. Therefore, size Wa6 from crossover wires 12b to the outer surface of metal outer cover <NUM> in motor <NUM> is <NUM>. Accordingly, an outer diameter of motor <NUM> is equal to an outer diameter of motor <NUM> of the comparative example described above in a state where an outer casing is molded using mold resin portion <NUM> except for metal outer cover <NUM>.

Both motors <NUM> and <NUM> thus configured were subjected to a dielectric voltage test under EN60335-<NUM>, which is an overseas standard. As a result, it was confirmed that both motors <NUM> and <NUM> satisfied the dielectric voltage test which applies AC 1500V - <NUM>.

As shown in <FIG>, the sizes of insulating film <NUM> and metal outer cover <NUM> at portions in contact with each other may be equalized in the molding of non-claimed Modification <NUM>. Specifically, step portion <NUM> is constituted by first step portion 429sa and second step portion 419sb sequentially located in axial direction X or radial direction Y from a center of stator 40a. A depth of first step portion 429sa is substantially equal to thickness ts of insulating film <NUM>. A depth of second step portion 419sb is substantially equal to thickness ts1 of metal outer cover <NUM>. On the other hand, unlike the modification shown in <FIG>, the length of insulating film <NUM> is substantially equal to the length of metal outer cover <NUM>.

In this configuration, step portion <NUM> formed on mold resin portion <NUM> can be produced in one step. Therefore, workability improves in a step of filling a mold with mold resin for molding stator 40a.

As apparent from the above description, according to the exemplary embodiment of the present invention and the non-claimed example, reduction of an increase in a size of an external shape of a motor is achievable while securing electrical insulation. Moreover, the molded motor to be provided is capable of preventing leakage of fire to the outside of the motor even if excessive currents flow in coils wound around a stator core.

The present invention is applicable to a wide range of so-called molded motors each covering a stator with mold resin.

Claim 1:
A molded motor (<NUM>) comprising:
a rotor (<NUM>) that includes a rotary shaft (<NUM>) extending in an axial direction, and a rotor core (<NUM>) holding a permanent magnet (<NUM>) and fixed to the rotary shaft (<NUM>);
a stator (<NUM>) that includes a stator core (<NUM>) on which a plurality of salient poles (11t) are arranged in a circumferential direction, and a plurality of coils (<NUM>) comprising coil ends (12a) that protrude from the stator core (<NUM>) toward both sides in the axial direction, each coil (<NUM>) wound via an insulator (<NUM>) around corresponding one of the salient poles (11t) of the stator core (<NUM>), and faces the rotor;
a bearing (<NUM>) on which the rotor (<NUM>) is rotatably supported;
a mold resin portion (<NUM>) that covers the stator (<NUM>) with mold resin;
a metal member (<NUM>) having a cup shape, the metal member (<NUM>) being mounted on an outer surface of the mold resin portion (<NUM>), and including a cylindrical portion (31c) having a cylindrical shape and a bottom surface portion (31a) forming a bottom surface of the cylindrical portion; and
an insulating material (<NUM>) having a cup shape which has a hole in a bottom surface portion thereof, the insulating material (<NUM>) being located between an outer surface of the mold resin portion (<NUM>) and an inner surface of the metal member (<NUM>), at least a part of a surface of the insulating material (<NUM>) being arranged at a portion facing the plurality of coils (<NUM>) arranged in the circumferential direction, characterized in that:
the insulating material (<NUM>) has higher electrical insulation than the mold resin portion (<NUM>),
wherein the insulating material (<NUM>) is an insulating film, and
wherein the cylindrical portion (31c) is located on an outer circumferential surface of the mold resin portion (<NUM>), at least a portion of the cylindrical portion (31c) facing the coil ends (12a) on both sides.