Patent ID: 12212198

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the drawings. Description of a preferable exemplary embodiment below is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses at all.

Exemplary Embodiment

[Configuration of Motor]

FIG.1is a schematic diagram of motor1000according to an exemplary embodiment of the present invention. In the following description, a radial direction of motor1000may be referred to as a “radial direction”, an outer circumferential direction thereof may be referred to as a “circumferential direction”, and an axis line direction of output shaft210of motor1000(a direction perpendicular to the paper surface inFIG.1) may be referred to as an “axial direction”. In the radial direction, an axial center side of motor1000may be referred to as radially inside, and an outer peripheral side may be referred to as radially outside.FIG.1does not illustrate first lead part41and second lead part42of coil40described later. When viewed from the axial direction, motor1000has an axial center aligning with an axis line of the output shaft210.

Motor1000includes stator100and rotor200. Although motor1000includes components other than the above components, such as a motor case and a bearing that rotatably supports the output shaft, illustration and description of those components are eliminated for convenience of description.

Stator100includes yoke20in an annular shape, teeth10, slots30, and coils40. Teeth10are connected to an inner periphery of yoke20and are provided at equal intervals along the inner periphery. Slots30are provided between respective teeth10adjacent to each other in the circumferential direction. Coils40are accommodated in respective slots30. Stator100is disposed radially outside rotor200at a predetermined interval from rotor200.

Teeth10and yoke20are each formed by, for example, being blanked out from electromagnetic steel sheets containing silicon and the like after being stacked. Coils40are attached to respective teeth10with respective insulators50(seeFIG.3B) interposed therebetween and accommodated in respective slots30. The shape of coil40will be described in detail later.

Corresponding to a phase of a current flowing through coil40, coils may be referred to as coils U1to U4, V1to V4, or W1to W4.

Rotor200includes output shaft210, rotor core220provided at its axial center with output shaft210, and magnets230that are embedded in rotor core220while facing stator100and that have N poles and S poles alternately disposed along an outer peripheral direction of the output shaft. Material, shape, and properties of magnet230can be appropriately changed in accordance with an output of motor1000, for example. Rotor core220is formed by, for example, being blanked out from electromagnetic steel sheets containing silicon and the like after being stacked.

Coils U1to U4, V1to V4, and W1to W4are independently connected in series. Three phase currents of U, V, and W phases different in phase by an electrical angle of 120° are supplied to coils U1to U4, V1to V4, and W1to W4, respectively, and excited, thereby generating a rotating magnetic field in stator100. The rotating magnetic field and a magnetic field generated by magnets230provided in rotor200interact with each other to generate torque, and thus output shaft210is rotated while being supported by a bearing (not illustrated).

[Structure of coil and main part of stator]FIG.2Ais a perspective view of a coil as viewed from a first turn side.FIG.2Bis a perspective view of the coil as viewed from an n-th turn side.FIG.3Aillustrates a main part of a stator as viewed from above.FIG.3Billustrates the main part of the stator as viewed from radially inward.FIG.3Cis an enlarged view of a main part of a plate.FIG.3Dis another enlarged view of a main part of the plate.FIG.3Eis yet another enlarged view of a main part of the plate.

As illustrated inFIGS.2A and2B, coil40includes first lead part41, second lead part42, and winding part43. Coil40is a molded coil formed with a conductive wire made of copper or the like having a quadrangular section. The conductive wire constituting coil40is provided on its surface with an insulating film (not illustrated). Similarly, an insulating member such as an insulator or an insulating sheet (not illustrated) is provided between tooth10and coil40illustrated inFIGS.3A and3B.

The “molded coil” in the present description does not include a coil obtained by only spirally winding a conductive wire having a constant width and thickness.

The molded coil is formed by, for example, preparing rectangular plates different in length, width, or thicknesses, pressing the plates, and joining the plates by cold welding, welding, or another method. The plate is made of a material that is a low-resistance material such as copper or aluminum. The plate formed partially in a different shape can be prepared by performing the following processing. For example, slit46or hole47is formed in the plate as illustrated inFIG.3C or3D. Alternatively, cutout48is formed in the plate as illustrated inFIG.3E.

Alternatively, the molded coil may be formed by so-called casting in which copper or the like is melted and poured into a casting mold. The molded coil may be formed by bending a conductive wire in a plate shape at a predetermined position, the conductive wire being preliminarily formed to be different in width or thicknesses midway. Alternatively, a conductive wire in a plate shape having a constant width and thickness may be rolled at a predetermined place, and wound in a spiral shape after being changed in width and thickness midway to form a molded coil. In short, the molded coil is formed by winding a conductive wire and further performing another processing on the conductive wire, or by a method different from a method in which the conductive wire is simply wound.

Winding part43includes first to n-th turns431to43nformed by spirally winding a conductive wire. Here, n is an integer of two or more. First to n-th turns431to43nare stacked in this order from a center side toward an outer peripheral side of motor1000and accommodated in slot30. Each of first to n-th turns431to43nhas a quadrangular ring shape having four sides when viewed from the radial direction.

Winding part43includes first coil end44and second coil end45. First coil end44corresponds to an upper end side in the axial direction among the four sides of first to n-th turns431to43n. Second coil end45corresponds to a lower end side portion in the axial direction among the four sides of first to n-th turns431to43n.

First lead part41is continuous with an end of first turn431. First lead part41is bent at the end of first turn431to extend to n-th turn43nalong an upper surface of first coil end44. First lead part41is further bent upward near n-th turn43n.

Second lead part42is continuous with n-th turn43n, and is bent in the middle of n-th turn43nto extend upward from first coil end44.

As illustrated inFIGS.2A to3B, end41aof first lead part41(hereinafter, simply referred to as end41a) and end42aof second lead part42(hereinafter, simply referred to as end42a) are disposed with a predetermined distance along the circumferential direction. In this case, the predetermined distance is shorter than a circumferential length of a part of first coil end44corresponding to n-th turn43n.

When viewed from the axial direction, end41aand end42aare disposed at positions equidistant from the center of motor1000. Specifically, when viewed from above, end41aand end42aare disposed on the same circumference centered on the axial center of yoke20, corresponding to the center of motor1000. In other words, when viewed from the axial direction, end41aand end42aare disposed radially equidistant from the outermost periphery of first coil end44, that is, from n-th turn43n.

End41aand end42aare disposed at the same height from the upper surface of first coil end44when viewed from the radial direction. Specifically, first lead part41and second lead part42are equal in length extending axially upward from the upper surface of first coil end44.

In the present application description, “identical”, “equal”, and “the same” include a manufacturing tolerance or an assembly tolerance of each component constituting motor1000, and do not mean that comparison targets are identical, equal, or the same in a strict sense.

First lead part41and second lead part42are identical in shape in a part extending from n-th turn43n. Specifically, first lead part41and second lead part42are equal in width. First lead part41and second lead part42are equal in thickness.

In general, slot30has a circumferential width increasing from a side closer to yoke20toward rotor200. According to the shape of slot30, n-th turn43nhas a wider width than first turn431in winding part43of coil40.

First lead part41is formed equal in width to first turn431. Second lead part42is formed narrower than n-th turn43nby being formed equal in width to first lead part41as described above.

As illustrated inFIGS.1,3A, and3B, coils40are disposed at equal intervals along the inner periphery of yoke20corresponding to placement of teeth10. According to this placement relationship, first lead parts41provided in respective coils40are disposed at equal intervals along the circumferential direction. Similarly, second lead parts42provided in respective coils40are disposed at equal intervals along the circumferential direction. An interval between first lead part41and second lead part42along the circumferential direction is equal for each coil40.

When viewed from the radial direction, end41aprovided in each of coils40and end42aprovided in each of coils40are located at the same height. For example, ends41aand ends42aare located at the same height with respect to the upper surface of first coil end44.

Each of first lead part41and second lead part42provided in one coil40functions as a connection part to another coil40. Alternatively, each of first lead part41and second lead part42functions as a connection part to corresponding one of bus bars61to63(seeFIG.3B), and to wiring. For example, when coils40of the same U phase described above are connected by welding, corresponding bus bars61to63(seeFIG.3B) or the wiring is welded to first lead part41and second lead part42provided in each of coils40. Thus, the insulating film is removed from a part of first lead part41, the part including end41a. Similarly, the insulating film is removed from a part of second lead part42, the part including end42a. Winding part43further functions as a magnetic field generator when a current flows therethrough.

[Effects and others] As described above, coil40according to the present exemplary embodiment is attached to motor1000. Coil40includes first lead part41, second lead part42, and winding part43.

Winding part43includes first to n-th (n is an integer of two or more) turns431to43nstacked in this order from the center side toward the outer peripheral side of motor1000when viewed from the radial direction. Winding part43includes first coil end44located on its upper side in the axial direction and second coil end45located on its lower side in the axial direction.

First lead part41extends from first turn431. Second lead part42extends from n-th turn43n.

First lead part41is bent to extend to the n-th turn43nalong the upper surface of first coil end44. End41aand end42aare equal in height from the upper surface of first coil end44when viewed from the radial direction, and are equidistant from the outermost periphery of first coil end44, or n-th turn43nwhen viewed from the axial direction. Coil40is the above described molded coil formed by forming a conductive wire.

Forming coil40as described above enables facilitating connection between coils40. In particular, end41aand end42aare identical in position when viewed from the radial direction and when viewed from the axial direction, so that a jig or the like does not need to be complicatedly moved when coils40are connected by welding or the like. Additionally, a conductive wire does not need to be manually routed to a welding position. As a result, connection equipment and an assembly step of motor1000can be standardized, and assembly cost of motor1000can be reduced.

Using the molded coil as coil40enables increasing a degree of freedom in shape design. As a result, first lead part41and second lead part42, and thus end41aand end42acan be disposed at appropriate positions suitable for shapes of stator100and motor1000, so that connection between coils40can be facilitated.

Second lead part42extends upward along the axial direction to allow end42ato be located above first coil end44. First lead part41is further bent upward near n-th turn43n.

Coil40formed as described above enables first lead part41and second lead part42, which are connection parts, to be disposed above coil40. Additionally, a jig, a welding head, and the like can be easily moved to connect coils40. As a result, the connection between coils40can be facilitated.

First lead part41and second lead part42are preferably identical in shape in a part extending from n-th turn43n. Specifically, first lead part41and second lead part42are preferably equal in thickness in the part extending from n-th turn43n. First lead part41and second lead part42are preferably equal in width that is in the circumferential direction in this case.

This structure does not require a jig, equipment placement, and the like to be changed between first lead part41and second lead part42when first lead part41and second lead part42are connected to corresponding bus bars61to63or the wiring, so that a connecting step can be standardized. Additionally, welding conditions can be uniformed to connect first lead part41and second lead part42to corresponding bus bars61to63or the wiring by welding, so that a welding step can be standardized.

Stator100includes at least yoke20in an annular shape, teeth10connected to an inner periphery of yoke20, and coils40wound around respective teeth10.

First lead parts41provided in respective coils40are disposed at equal intervals along the circumferential direction. Second lead parts42provided in respective coils40are disposed at equal intervals along the circumferential direction. When viewed from the radial direction, end41ais located at the same height as end42a. When viewed from the axial direction, end41aand end42aare located on the same circumference about the axial center of yoke20.

Ends41a,42aeach have a height with respect to a reference position that is an axial upper end surface of insulator50or an insulating sheet (not illustrated) attached to tooth10. As described above, the axial center of yoke20corresponds to the center of motor1000.

Stator100formed as described above allows positions of first lead part41and second lead part42to be regularly fixed in stator100. This structure enables facilitating connection between coils40different from each other or between coils40and corresponding bus bars61to63. The coils also enable a connecting step to be standardized.

In particular, welding work between coils40different from each other or between coils40and corresponding bus bars61to63is performed by rotating stator100at equal intervals, or for each placement pitch of coils40in this case, under conditions where stator100is rotatably held about the axial center of yoke20. As a result, the welding work can be greatly simplified.

The positions of first lead part41and second lead part42in stator100are regularly fixed, so that a place other than a connecting part can be easily masked during connecting work. For example, when a place other than a welding place is covered with a cover or the like (not illustrated) during the welding work between first lead part41or second lead part42and corresponding bus bars61to63, spatters or the like generated during welding can be prevented from scattering to the periphery and damaging the insulating film on coil40. This structure enables preventing an unintended short-circuit between coils40, between coils40and teeth10, or between coils40and yoke20, so that an initial defect of stator100can be suppressed. As a result, assembly cost of stator100can be reduced. Additionally, quality of stator100can be maintained.

Stator100of the present exemplary embodiment enables connecting work between adjacent coils40to be facilitated. As a result, when motor1000is of a delta connection type, for example, welding between adjacent coils40can be facilitated. Thus, assembly work of stator100can be simplified.

Motor1000according to the present exemplary embodiment includes at least rotor200provided at its axial center with output shaft210, and stator100provided coaxially with rotor200and at a predetermined interval from rotor200.

Motor1000of the present exemplary embodiment enables facilitating connecting work between coils40or between coils40and corresponding bus bars61to63or the like, and enables a connecting step to be standardized. As a result, the assembly cost of stator100and thus of motor1000can be reduced. Additionally, quality of motor1000can be maintained.

As described above, coil40of the present exemplary embodiment is attached to motor1000in which rotor200rotates about the axis line, and includes winding part43including first to n-th (n is an integer of two or more) turns stacked in this order from the center side toward the outer peripheral side of motor1000when viewed from the radial direction of motor1000orthogonal to the axis line, first lead part41extending from the first turn, and second lead part42extending from the n-th turn. Winding part43includes first coil end44located on a first side in the axial direction in which the axis line extends, and second coil end45located on a second side in the axial direction. First lead part41is bent to extend to the n-th turn along a surface of first coil end44, the surface being located on the first side, and end41aof first lead part41and end42aof second lead part42are equal in height from the surface of first coil end44, the surface being located on the first side, when viewed from the radial direction, and are equidistant from the n-th turn when viewed from the axial direction.

This structure enables simple connections between the coils, and between each coil and a bus bar and the like. The coils also enable a connecting step to be standardized.

Second lead part42preferably extends toward the first side along the axial direction and includes an end located on the first side of first coil end44, and first lead part41is preferably further bent toward the first side near the n-th turn.

Second lead part42is preferably bent toward the outer peripheral side of motor1000near the surface of first coil end44, the surface being located on the first side.

First lead part41is preferably equal in thickness to second lead part42, and is preferably equal in width to second lead part42.

Stator100of the present exemplary embodiment includes yoke20in an annular shape, teeth10connected to an inner periphery of yoke20, and coils40wound around respective teeth10, coils40being each the coil of the present exemplary embodiment described above, and coils40including: first lead parts41that are provided in respective coils40and that are disposed at equal intervals along a circumferential direction of motor1000; and second lead parts42that are provided in respective coils40and that are disposed at equal intervals along the circumferential direction, first lead parts41each including end41alocated at a height equal to a height of end42aof each of second lead parts42when viewed from the radial direction, and end41aof each of first lead parts41and end42aof each of second lead parts42, being located on an identical circumference about the axial center of yoke20.

This structure enables a simple connection between coils that are adjacent to each other or separated from each other. The coils also enable a connecting step to be standardized.

First lead parts41and corresponding second lead parts42are preferably disposed at equal intervals.

Motor1000of the present exemplary embodiment includes at least rotor200provided at its axial center with output shaft210, and stator100of the present exemplary embodiment described above, stator100being provided coaxially with rotor200and at a predetermined interval from rotor200.

This structure enables an assembly step of the stator to be standardized. This structure also enables reduction in assembly cost.

<First Modification>

FIG.4is a perspective view of a coil according to a first modification.FIG.5is a perspective view of another coil according to the first modification. InFIGS.4and5, and the subsequent drawings, a part similar to that of the exemplary embodiment is denoted by the same reference numeral, and detailed description thereof will be eliminated.

The present modification shows a structure that is different from the structure shown in the exemplary embodiment in the following points.

Second lead part42is bent in the middle of n-th turn43nto extend radially outward. First lead part41is bent at an end of first turn431to extend radially outward of n-th turn43nalong an upper surface of first coil end44.

First lead part41and second lead part42both extend along the radial direction, and end41aand end42aare on the same circumference centered on the axial center of yoke20. In this case, end41aand end42aare at respective positions that are identical and radially outward of coil40. As illustrated inFIG.4, end41aand end42aare substantially equal in height when viewed from the axial direction. In this case, end41aand end42aare at respective positions that are closer to the upper surface of first coil end44than those in the structure shown in the exemplary embodiment and that are identical axially.

When coil40is formed as described above, height of each of end41aand end42aas viewed from the radial direction can be reduced to lower than that in the structure shown in the exemplary embodiment. As a result, coil40including a connection part can be reduced in height.

When end41aand end42aare disposed radially outward of n-th turn43nof coil40, a space can be secured above first coil end44. As a result, wiring and a bus bar, which are not illustrated, can be disposed above first coil end44. Thus, coil40including the wiring and the bus bar can be reduced in height and size.

In particular, when there is a margin in a space between n-th turn43ncorresponding to the radially outermost side of coil40and yoke20or a motor case (not illustrated) accommodating stator100and rotor200, the structure shown in the present modification is effective in reducing coil40in height and size.

When end41aand end42aare desired to be exactly equal in distance in the radial direction from n-th turn43nthat is the outermost periphery of first coil end44as viewed from the axial direction, first lead part41extending radially outward from n-th turn43nmay be bent downward in the middle, for example. As illustrated inFIG.5, first lead part41extending radially outward of n-th turn43nmay be further bent multiple times along the upper surface of first coil end44. That is, when viewed from the axial direction, first lead part41and second lead part42are bent downward to extend radially outward, and are further bent upward in the axial direction.

End41ais located at the same height as the upper surface of first coil end44when viewed from the radial direction. End42ais located at the same height as end41awhen viewed from the radial direction.

When coil40is formed as described above, height of each of end41aand end42aas viewed from the radial direction can be reduced to lower than that in the structure shown in the first modification. Thus, welding in the axial direction can be reduced in height. As a result, coil40including a connection part can be reduced in height.

When end41aand end42aare disposed radially outward of n-th turn43nof coil40, a space can be secured above first coil end44. As a result, wiring and a bus bar, which are not illustrated, can be disposed above first coil end44. Thus, coil40including the wiring and the bus bar can be reduced in height and size.

In particular, when there is a margin in a space between n-th turn43ncorresponding to the radially outermost side of coil40and yoke20or a motor case (not illustrated) accommodating stator100and rotor200, the structure shown in the present modification is effective in reducing coil40in height and size.

End41amay be flush with the upper surface of first coil end44or located below the upper surface when viewed from the radial direction. In this case, second lead part42may be bent downward from an end of n-th turn43nto extend radially outward, thereby allowing end42ato be equal in height to end41awhen viewed from the radial direction.

As described above, coil40of the present modification may be configured such that first lead part41extends outward of the n-th turn when viewed from the radial direction and is bent multiple times outside the n-th turn.

<Second Modification>

FIG.6Ais a perspective view of a coil according to a second modification.FIG.6Bis a schematic sectional view taken along line VIB-VIB inFIG.6A. The present modification shows a structure that is different from the structure shown in the exemplary embodiment in the following points.

Coils40adjacent to each other in the circumferential direction include first coil ends44facing each other in which corners44aare chamfered. First lead part41extends to n-th turn43nthrough between corners44aof respective first coil ends44, and is bent upward near n-th turn43n.

When coil40is formed as described above, height of end41aas viewed from the radial direction can be reduced to lower than that in the structure shown in the exemplary embodiment. As a result, coil40including a connection part can be reduced in height.

When first lead part41is disposed between corners44aof first coil ends44facing each other in the circumferential direction, a space can be secured above first coil ends44. As a result, wiring and a bus bar can be disposed above first coil end44, so that coil40including the wiring and the bus bar can be reduced in height and size.

First coil end44includes corner44athat has a larger sectional area than other parts of first to n-th turns431to43n. Thus, even when corner44ahas a chamfered shape, coil40hardly increases in resistance to enable suppressing an increase in loss when a current flows through coil40.

Corner44aof first coil end44may have a linearly chamfered shape as illustrated inFIG.6A. Alternatively, corner44aof first coil end44may have, for example, a round chamfered shape. Corner44ahas a rounded shape in the latter case, so that damage or the like to the insulating film of first lead part41can be suppressed, for example. The latter case also enables stress concentration on corner44ato be relieved.

Coils40shown in the present modification are attached to respective teeth10illustrated inFIG.1to constitute stator100.

According to the present modification, coil40is reduced in height and size. Thus, stator100itself can be downsized in the axial direction. When corner44aof first coil end44has a round chamfered shape, damage or the like to the insulating film of first lead part41can be suppressed. Thus, a leak current from coil40to tooth10or yoke20can be suppressed. As a result, a decrease in strength of a rotating magnetic field generated in stator100can be suppressed.

As described above, stator100of the present modification may be configured such that coils40adjacent to each other include first coil ends44facing each other and having corners44ain a chamfered shape, and first lead part41is accommodated between corners44aof first coil ends44facing each other and extends to the n-th turn or extends radially outward of the n-th turn.

<Third Modification>

FIG.7is a perspective view of a coil according to a third modification. The present modification shows a structure that is different from the structure shown in the exemplary embodiment in the following points.

First lead part41is bent in the circumferential direction and the radial direction above an upper surface of first coil end44to be located diagonally from an end of first turn431when viewed from the axial direction. Second lead part42is disposed at a predetermined interval from first lead part41in the circumferential direction when viewed from the axial direction.

The present modification enables positions of end41aand end42ain coil40to be interchanged with respect to coil40shown in the exemplary embodiment. As a result, a degree of freedom of connection between coils40in stator100can be increased. For example, when first lead parts41are desired to be connected to each other between coils40adjacent to each other, two first lead parts41can be brought close to each other. Thus, connecting work is facilitated. Additionally, a degree of freedom of routing wiring and a bus bar for connecting coils40can be increased. Thus, motor1000can be reduced in design cost.

As described above, coil40of the present modification may be configured such that first lead part41is bent in the circumferential direction and the radial direction about the axis line above a surface of first coil end44, the surface being located on a first side, to be located diagonally from the end of the first turn when viewed from the axial direction, and second lead part42is disposed at a predetermined interval from first lead part41in the circumferential direction when viewed from the axial direction.

<Fourth Modification>

FIG.8is a schematic view of a winding part of a coil according to a fourth modification as viewed from the radial direction.FIG.8does not illustrate first lead part41and second lead part42.

The present modification shows a structure that is different from the structure shown in the exemplary embodiment in that a height of first coil end44, or height A in the axial direction in this case, is lower than height B of second coil end45.

When coil40, especially winding part43, is formed as described above, an axial length of each of first lead part41and second lead part42can be increased to more than that in the structure shown in the exemplary embodiment without changing heights of end41aand end42awith respect to an upper surface of first coil end44.

This structure enables widening a space capable of accommodating a jig or a welding head when first lead part41and second lead part42are connected to another member such as a bus bar. Thus, connecting work is facilitated.

When coil40, especially winding part43, is formed as described above, end41aand end42acan be located lower than those in the structure shown in the exemplary embodiment when the axial length of each of first lead part41and second lead part42with respect to the upper surface of first coil end44is not changed. As a result, coil40can be reduced in height and size.

As described above, coil40of the present modification may be configured such that first coil end44has an axial height lower than an axial height of second coil end45.

Other Exemplary Embodiments

The components shown in the exemplary embodiment and the modifications described above can be appropriately combined to form an additional exemplary embodiment. For example, winding part43shown in the fourth modification may be applied to the structure shown in the exemplary embodiment or first to third modifications.

Although the conductive wire constituting coil40has a sectional shape of a quadrangle, the sectional shape is not particularly limited, and may be another shape. For example, the shape may be an m-polygon (m is an integer of three or more).

Depending on specifications of motor1000and stator100, coil40may be connected to wiring or a bus bar below coil40. In this case, first lead part41is bent to extend to n-th turn43nalong a lower surface of second coil end45, for example. Even in this case, end41aand end42aare equal in height from an upper surface of first coil end44when viewed from the radial direction, and are equidistant from n-th turn43nwhen viewed from the axial direction. This structure described above enables achieving effects similar to those achieved by the structure shown in the exemplary embodiment.

The coil of the present invention facilitates connection between coils or to a bus bar, and is useful for application to a motor.