Substrate laminate and rotating electric machine

Abstract

To provide a substrate laminate capable of achieving both weight reduction and improved energy efficiency of a rotating electrical machine.SOLUTION: A substrate laminate is formed by stacking a plurality of band-shaped flexible circuit boards bent in a cylindrical shape in a radial direction of the cylinder. Each of the plurality of flexible circuit boards has continuous wiring formed by alternately connecting a plurality of pieces of partial wiring formed on two main surfaces of a band-shaped insulating sheet through vias, which intersects in a chain shape without mutual conduction in a projected plan view seen from a normal direction of the main surface of the insulating sheet to form a plurality of ring-shaped portions. A length of the insulating sheet increases as the plurality of flexible circuit boards are arranged to be farther from a central axis of the cylinder.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a substrate laminate and a rotating electric machine using the same. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have become more active, and research and development is being conducted on electrification and weight reduction in vehicles to reduce CO2 emissions and improve energy efficiency.

[0003] One known technique for reducing the weight of motors required for electrification is to construct stator coils using flexible circuit boards. For example, Patent Document 1 describes a stator constructed by winding a strip-shaped insulating sheet that has multiple holes into which magnetic cores are inserted and multiple coil patterns formed in a spiral shape around each hole, arranged in the longitudinal direction. In this stator, overlapping coil patterns are cascade-connected in the wound insulating film to form a laminated coil around the holes.

[0004] Patent Document 2 discloses a motor in which teeth that form a stator core are sandwiched between a first sheet substrate and a second sheet substrate. A plurality of conductive patterns are formed at regular intervals on one side of each of the first and second sheets. The first sheet substrate is folded into a concave shape and fitted onto the teeth, and then the first and second sheet substrates are placed face to face with the teeth sandwiched between them, and the ends of the conductive patterns are joined to form a coil with the teeth as its core.

[0005] Patent Document 3 discloses a coreless motor that uses an armature formed by stacking two flexible circuit boards and winding them into a cylindrical shape. The flexible circuit board has a dogleg-shaped group of parallel conductor wires formed on one side, with metal conductor protrusion array groups exposed from both ends of each parallel conductor wire group toward the outside of the board. Two flexible circuit boards are stacked in opposite directions and wound into a cylindrical shape, and the opposing metal conductor protrusion array groups are joined, thereby connecting the conductor wires of the two parallel conductor wire groups of the two flexible circuit boards to form a coil. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-067756 [Patent Document 2] Japanese Patent Application Publication No. 11-297557 [Patent Document 3] Japanese Patent Application Publication No. 55-127852 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the technology for reducing the weight of motors, it is necessary to improve the performance of stator coils made of flexible circuit boards to realize motors with high energy efficiency, which is a common issue for rotating electrical machines, including generators that have a similar configuration to motors. In order to solve the above-mentioned problems, the present application has an object to provide a substrate laminate of flexible circuit boards that can achieve both weight reduction and improved energy efficiency of a rotating electrical machine. [Means for solving the problem]

[0008] One aspect of the present invention is a substrate laminate constructed by stacking a plurality of strip-shaped flexible circuit boards bent into a cylindrical shape in the radial direction of the cylinder, wherein each of the plurality of flexible circuit boards includes a strip-shaped insulating sheet and at least one continuous wiring formed on the insulating sheet, the continuous wiring including a first continuous portion and a second continuous portion extending in the longitudinal direction of the insulating sheet, formed by alternately connecting a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet via vias, the first continuous portion and the second continuous portion intersecting in a chain-like manner without being conductive to each other in a projected plan view seen from the normal direction to the main surface of the insulating sheet, forming a plurality of annular portions connected in a chain-like manner, and the flexible circuit boards arranged farther from the central axis of the cylinder have longer insulating sheets. According to another aspect of the present invention, each of the multiple flexible circuit boards has at least one protrusion arranged on at least one of the two long sides extending in the longitudinal direction of the insulating sheet, protruding from the long side toward the outside of the insulating sheet, and the multiple flexible circuit boards arranged farther from the central axis of the cylinder have a longer distance measured along the longitudinal direction of the insulating sheet from one end of the longitudinal direction of the insulating sheet to the protrusion. According to another aspect of the present invention, the more the flexible circuit boards are arranged farther from the central axis of the cylinder, the longer the length of the chain-like annular portions of the flexible circuit boards measured along the longitudinal direction of the insulating sheet. According to another aspect of the present invention, the width of the partial wiring that constitutes the continuous wiring is larger in the flexible circuit boards that are disposed farther from the central axis of the cylinder. According to another aspect of the present invention, each of the plurality of flexible circuit boards includes a plurality of the continuous wirings formed at positions offset from one another along the longitudinal direction of the insulating sheet. Another aspect of the present invention is a rotating electric machine having a stator including the substrate laminate, and a rotor disposed inside a cylinder formed by the substrate laminate. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a substrate laminate of flexible circuit boards that can achieve both weight reduction and improved energy efficiency of a rotating electrical machine. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a flexible circuit board according to the first embodiment. [Figure 2] For the sake of explanation, FIG. 2 shows only the continuous wiring of the U phase of the flexible circuit board shown in FIG. 1, and omits other continuous wiring. [Figure 3] 3 is a partial detailed view of part A shown in FIG. 2, showing the configuration of the connection conductor portion of the flexible circuit board shown in FIG. [Figure 4] FIG. 4 is a diagram showing an example of a configuration according to the related art regarding connections between partial wirings via vias. [Figure 5] FIG. 5 is a diagram showing an example of the configuration of a motor in which the flexible circuit board shown in FIG. 1 is used. [Figure 6] FIG. 6 is a diagram showing the configuration of a flexible circuit board according to a modified example of the first embodiment. [Figure 7] FIG. 7 is a diagram showing the configuration of a substrate stack according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing the configuration of a flexible circuit board that constitutes the substrate laminate shown in FIG. [Figure 9] FIG. 9 is a diagram showing only the continuous wiring of the U phase of the flexible circuit board shown in FIG. 8, omitting other continuous wiring. [Figure 10] 10 is a cross-sectional view of the substrate laminate shown in FIG. 7 taken along line XX. [Figure 11] FIG. 11 is a diagram showing an example of the configuration of a motor in which the substrate laminate shown in FIG. 7 is used. [Figure 12]FIG. 12 is a diagram showing an example of the configuration of a magnetic case in which the substrate laminate is disposed in the motor shown in FIG. [Figure 13] FIG. 13 is a diagram showing the configuration of a flexible circuit board according to a first modified example of the second embodiment. [Figure 14] FIG. 14 is a diagram showing the configuration of a flexible circuit board according to a second modified example of the second embodiment. [Figure 15] FIG. 15 is a diagram showing the configuration of a flexible circuit board according to a third modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The above-described conventional technology requires a process of connecting the coil patterns of multiple flexible circuit boards formed with coil patterns to each other after stacking them, which complicates the manufacturing process and the stator structure. Furthermore, in the conventional configuration, the connections between the coil patterns are made of a different material (e.g., welding material or conductive paste) than the coil patterns, or due to variations in the connection area caused by misalignment between the coil patterns during the manufacturing process, which causes discontinuities in electrical resistance compared to other conductor parts, making them more susceptible to heat generation. The heat generated at these connections increases the temperature of the stator core around the coil patterns, reducing the magnetic susceptibility of the stator core and potentially degrading the characteristics of the rotating electric machine.

[0012] The following describes the embodiments.

[0013] [1. First embodiment] [1.1 Structure of flexible circuit board] First, the configuration of a flexible circuit board 10 according to the first embodiment will be described. The flexible circuit board 10 shown in Fig. 1 is used to form a stator of a rotating electric machine. The rotating electric machine in which the flexible circuit board 10 is used is, for example, a motor 20, which is a three-phase brushless motor shown in Fig. 5. However, the rotating electric machine in which the flexible circuit board 10 is used is not limited to a motor, and may also be, for example, a generator configured in the same way as the motor 20.

[0014] The motor 20 shown in Fig. 5 is composed of a stator 21 and a rotor 22. The stator 21 is composed of a case 23 made of a soft magnetic material processed into a cylindrical cup shape, and a flexible circuit board 10 (the hatched portion in Fig. 5) arranged along the inner periphery of the case 23. As will be described later, wiring that forms a coil is formed on the flexible circuit board 10. The rotor 22 is composed of a rotating body 24 made of a magnetic material processed into a cylindrical cup shape, and a plurality of permanent magnets 25 attached to or embedded in the outer periphery of the rotating body 24.

[0015] By using the flexible circuit board 10 that forms the coil for the stator 21, it is possible to reduce the weight of the stator compared to a general stator that has a coil formed by winding a conductor. Note that the stator 21 may be arranged on the inner periphery of the rotor 22.

[0016] 1, the flexible circuit board 10 includes a flexible, strip-shaped insulating sheet 11 extending left and right in the figure, and a plurality of conductor patterns, such as a first partial wiring U1 and a second partial wiring U2 (described later), formed on two opposing main surfaces of the insulating sheet 11. The partial wirings formed on the two main surfaces are alternately connected in cascade through vias to form three independent continuous wirings Uc, Vc, and Wc. Line currents (hereinafter simply referred to as currents) of the U, V, and W phases of a three-phase alternating current are passed through the three continuous wirings Uc, Vc, and Wc from external terminals Up, Vp, and Wp, respectively.

[0017] Each of the three continuous wirings Uc, Vc, and Wc includes a first continuous portion Us1, Vs1, and Ws1 and a second continuous portion Us2, Vs2, and Ws2 that extend in the longitudinal direction of the insulating sheet 11. In each of the continuous wirings Uc, Vc, and Wc, the first continuous portion Us1, Vs1, and Ws1 and the second continuous portion Us2, Vs2, and Ws intersect in a chain-like manner without being electrically connected to each other in a projected plan view seen from the normal direction of the main surface of the insulating sheet 11 (for example, the plan view shown in FIG. 1). In each of the continuous wirings Uc, Vc, and Wc, the first continuous portion Us1, Vs1, and Ws1 intersect in a chain-like manner with the second continuous portion Us2, Vs2, and Ws, forming a plurality of annular portions connected in a chain-like manner, each of which forms a single coil.

[0018] Hereinafter, the main surface of the flexible circuit board 10 shown in Fig. 1 will be referred to as the second main surface or front surface, and the main surface opposite to the second main surface shown in Fig. 1 will be referred to as the first main surface or back surface. In Fig. 1, the conductor patterns formed on the first main surface (back surface) are indicated by dashed lines, and the conductor patterns formed on the second main surface (front surface) are indicated by solid lines. This also applies to other drawings showing the configuration of a flexible circuit board.

[0019] In addition, in FIG. 1, the longitudinal direction of the strip-shaped insulating sheet 11, that is, the left-right direction in the drawing, is the X direction (the right direction in the drawing is the +X direction), and the vertical direction in the drawing, that is, the width direction of the insulating sheet 11 perpendicular to the X direction, is the Y direction (the up direction in the drawing is the +Y direction).

[0020] Of the two sides extending in the longitudinal direction (±X direction) of the strip-shaped insulating sheet 11, the side on the upper side in the figure is referred to as long side 12a, and the side on the lower side in the figure is referred to as long side 12b. Of the two sides extending in the width direction (±Y direction) of the strip-shaped insulating sheet 11, the side on the left side in the figure is referred to as short side 12c, and the side on the right side in the figure is referred to as short side 12d.

[0021] In the motor 20, the flexible circuit board 10 is bent into a cylindrical shape so that the short side 12c and the short side 12d face each other, and is placed inside the case 23. The inner surface of the cylinder in the bent state may be either the first main surface or the second main surface of the insulating sheet 11. In this embodiment, for example, the inner surface of the cylinder is the second main surface (front surface).

[0022] The configuration of the three continuous wirings Uc, Vc, and Wc formed on the flexible circuit board 10 and through which U-phase, V-phase, and W-phase currents are passed will be described below.

[0023] For ease of explanation, Fig. 2 shows only the continuous wiring Uc through which a U-phase current flows, out of the three continuous wirings Uc, Vc, and Wc formed on the flexible circuit board 10 shown in Fig. 1. In the flexible circuit board 10, the other continuous wirings Vc and Wc through which V-phase and W-phase currents flow, respectively, are configured in the same manner as the U-phase continuous wiring Uc shown in Fig. 2.

[0024] 2, the continuous wiring Uc through which a U-phase current flows includes a first continuous portion Us1 and a second continuous portion Us2 extending in the X direction, which is the longitudinal direction of the insulating sheet 11. The first continuous portion Us1 is configured by first partial wiring U1a, U1c, U1e, U1g, U1i, and U1k formed on the first main surface (back surface) of the insulating sheet 11 and second partial wiring U2a, U2c, U2e, U2g, U2i, and U2k formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0025] In addition, the second continuous portion Us2 is composed of first partial wirings U1b, U1d, U1f, U1h, U1j, and U1m formed on the first main surface (back surface) and second partial wirings U2b, U2d, U2f, U2h, U2j, and U2m formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0026] Hereinafter, the first partial wirings U1a, U1b, U1c, U1d, U1e, U1f, U1g, U1h, U1i, U1j, U1k, and U1m will be collectively referred to as the first partial wiring U1. Furthermore, the second partial wirings U2a, U2b, U2c, U2d, U2e, U2f, U2g, U2h, U2i, U2j, U2k, and U2m will be collectively referred to as the second partial wiring U2.

[0027] The vias h connecting the first partial wiring U1 and the second partial wiring U2 are provided in the connection conductor portions Jc extending from the ends of the adjacent first partial wiring U1 and second partial wiring U2 toward the nearest long side 12a or 12b, respectively. Note that in Fig. 2, the symbol h is assigned only to the via in the connection conductor portion Jc at the top left of the figure, but it should be understood that similar vias are provided in the other connection conductor portions Jc.

[0028] One end of the first continuous portion Us1 (the left end in FIG. 1) is connected to the external terminal Up to which U-phase current is input. The other end of the first continuous portion Us1 (the right end in FIG. 1) and one end of the second continuous portion Us2 (the right end in FIG. 1) are cascade-connected and electrically connected via the conductor pattern constituting the inverted portion Ut. The other end of the second continuous portion (the left end in FIG. 1) is connected to the conductor pattern constituting the common connection portion Cc. The common connection portion Cc is also connected to the ends of continuous wiring Vc and Wc, through which V-phase and W-phase currents, described below, flow (see FIG. 1). This connection forms continuous wiring Uc, which is electrically connected from the external terminal Up to the first continuous portion Us1 to the inverted portion Ut to the second continuous portion Us2 to the common connection portion Cc.

[0029] As shown in the figure, the first partial wiring U1 and the second partial wiring U2 are each a plurality of linear conductor patterns having the same line width arranged in parallel in the longitudinal direction of the insulating sheet 11. Furthermore, the first partial wiring U1 and the second partial wiring U2 are inclined at an acute angle θ in line symmetry with respect to a line segment (a vertical line indicated by a two-dot chain line in the figure) along the Y direction (i.e., the width direction of the insulating sheet 11).

[0030] As a result, the first continuous portion Us1 and the second continuous portion Us2 included in the U-phase continuous wiring Uc intersect in a chain-like manner without electrical continuity when viewed in a projected plan view normal to the main surface of the insulating sheet 11 (normal to the paper surface in FIGS. 1 and 2 ). (In other words, the intersection of the first continuous portion Us1 and the second continuous portion Us2 is insulated by the insulating sheet 11 and does not conduct electricity.) Each of the diamond-shaped annular portions CR (more specifically, the annular portions enclosed by the dashed-dotted lines in the figure) that are connected in a chain-like manner constitutes a single coil. Note that in FIG. 2 , only the annular portion on the left side of the figure is designated by the symbol CR, but it should be understood that each of the annular portions of the same diamond shape connected in the horizontal direction in the figure is an annular portion CR.

[0031] The rhombus shape of the annular portion CR is due to the fact that the first partial wiring U1 and the second partial wiring U2 are formed as linear conductor patterns that are inclined and line-symmetrical with respect to each other, as described above.

[0032] For explanatory purposes, in Fig. 2, as an example, the direction of the U-phase current flowing from the external terminal Up is indicated by dotted or solid straight arrows near the first partial wiring U1 and the second partial wiring U2. In this current direction, for example, the first diamond-shaped annular portion CR from the left in the figure, formed by the first partial wiring U1c and the second partial wiring U2a constituting the first continuous portion Us1 and the first partial wiring U1b and the second partial wiring U2b constituting the second continuous portion Us2, forms an equivalent coil in which current flows counterclockwise, as indicated by the circular thick arrow. As a result, an N-pole is generated on the second main surface side (front surface side) of the first annular portion CR.

[0033] The second diamond-shaped annular portion CR from the left in the figure, formed by the first partial wiring U1c and the second partial wiring U2c that make up the first continuous portion Us1 and the first partial wiring U1d and the second partial wiring U2b that make up the second continuous portion Us2, forms an equivalent coil in which current flows clockwise as indicated by the circular thick arrow, which generates an S pole on the second main surface side (front surface side) of the second annular portion CR.

[0034] Similarly, each annular portion CR constitutes a coil, and adjacent coils generate magnetic poles that are opposite to each other. In addition, the magnetic field of each coil is reversed when the direction of the U-phase current flowing through the external terminal Up is reversed, thereby generating an alternating magnetic field.

[0035] The coil formed by each annular portion CR forms one stator slot that generates a U-phase alternating magnetic field when the flexible circuit board 10 is placed in the case 23 of the motor 20. In this embodiment, ten annular portions CR form ten U-phase stator slots.

[0036] In this embodiment, the two ends of the first partial wiring U1 and the second partial wiring U2 formed on the first and second main surfaces of the insulating sheet 11 are respectively arranged along the two opposing long sides 12a and 12b of the insulating sheet 11. As a result, the annular portion CR formed by the first continuous portion Us1 and the second continuous portion Us2 crossing each other in a chain shape spreads across almost the entire width of the insulating sheet 11, and a large area can be secured for each, thereby increasing the generated magnetic force.

[0037] In this embodiment, in particular, the vias h that alternately connect the first partial wiring U1 and the second partial wiring U2 are arranged in the connection conductor portions Jc that extend from the end of the first partial wiring U1 and the end of the second partial wiring U2 that overlap with each other across the insulating sheet 11 toward the closer of the two long sides 12a, 12b of the insulating sheet 11. As described above, the two ends of each of the first partial wiring U1 and the second partial wiring U2 are arranged along the two opposing long sides 12a and 12b of the insulating sheet 11, and therefore the connection conductor portions Jc are also arranged along the long sides 12a and 12b.

[0038] Fig. 3 is a partial detailed view of part A shown in Fig. 2, showing the configuration of the connection conductor Jc. Note that in Fig. 2, the connection conductor Jc other than part A is also configured in the same way as the connection conductor Jc shown in Fig. 3. 3, the first partial wiring U1a and the second partial wiring U2a are connected to the connection conductor portion Jc (the hatched portion in the figure) from directions forming an acute inclination angle θ symmetrically with respect to the Y direction, which is the width direction of the insulating sheet 11. In Fig. 3, the dashed dotted line en indicates the positions of the ends of the first partial wiring U1a and the second partial wiring U2a.

[0039] The portion of the connecting conductor Jc formed on the second main surface (front surface) of the insulating sheet 11 (the portion depicted by the solid line in the figure) extends over a distance Lc from the end of the second partial wiring U2a along the Y direction toward the closer of the two long sides 12a, 12b of the insulating sheet 11. Similarly, the portion of the connecting conductor Jc formed on the first main surface (back surface) of the insulating sheet 11 (the portion depicted by the dotted line in the figure) extends over a distance Lc from the end of the first partial wiring U1a toward the long side 12a of the insulating sheet. Hereinafter, the distance Lc will also be referred to as the extension distance Lc.

[0040] Here, the ends of the first partial wiring U1a and the second partial wiring U2a indicated by the lines en are aligned along the X direction, which is the longitudinal direction of the insulating sheet 11, and the length wd2 of these ends is the width of the first partial wiring U1a and the second partial wiring U2a measured along the longitudinal direction. The connecting conductor portion Jc is formed as a rectangular pattern whose width measured along the longitudinal direction (X direction) is the same as the length of the ends, wd2, and whose length measured along the width direction (Y direction) of the insulating sheet 11 is an extension distance Lc.

[0041] As a result, heat generated by current flowing through the vias h (white portions in the drawing) connecting the first partial wiring U1a and the second partial wiring U2a is quickly conducted to the vicinity of the long sides 12a of the insulating sheet 11 through the conductor foil of the connecting conductor portion Jc. Therefore, when the flexible circuit board 10 is housed in the case 23 of the motor 20, the generated heat is efficiently dissipated from the long sides 12a through the outer peripheral wall of the case 23 to the outside of the motor 20.

[0042] Furthermore, the length wd2 of the ends of the first partial wiring U1a and the second partial wiring U2a has a relationship with the line width wd1 of the first partial wiring U1a and the second partial wiring U2a (i.e., the width in a direction perpendicular to the extension direction of each partial wiring) given by the following equation (1). wd2=wd1÷cosθ (1)

[0043] Here, since the inclination angle θ is an acute angle (<90°), wd2 is a larger value than wd1. As a result, the diameter r1 of the circular via h formed in the connection conductor portion Jc can be set larger than the diameter r2 of the via v formed in the simple overlapping portion of two conductor patterns Cp1 and Cp2 having a line width wd1, as shown in Figure 4. Therefore, in the flexible circuit board 10, the electrical resistance of the via h can be made smaller than that of the via v configured as shown in Figure 4, and the heat generated in the via h can be reduced more than that in the case of the via v.

[0044] 4, the area in which the vias v are formed is limited to the intersection of the two linear conductor patterns Cp1 and Cp2, whereas in the flexible circuit board 10, the connecting conductor Jc can easily have a large area in which vias h can be formed by increasing its extension distance Lc. Therefore, in the flexible circuit board 10, multiple vias h can be formed in one connecting conductor Jc, thereby lowering the electrical resistance of the entire connecting conductor Jc including the multiple vias h and further reducing the heat generated in the connecting conductor Jc.

[0045] If the line width of the first partial wiring U1a corresponding to wd1 is different from the line width of the second partial wiring U2a, the length of the end of the first partial wiring U1a corresponding to Wd2 will be different from the length of the end of the second partial wiring U2a. In this case, the connection conductor Jc formed on the first main surface may be formed so that its longitudinal width is the length of the end of the first partial wiring U1a corresponding to wd2, and the connection conductor Jc formed on the second main surface may be formed so that its longitudinal width is the length of the end of the second partial wiring U2a corresponding to wd2.

[0046] Here, from the viewpoint of reducing heat generation in the connection conductor portion Jc, it is desirable that the electrical resistance per area, i.e., resistivity, of the connection conductor portion Jc including the vias h (i.e., the entire connection conductor portion Jc including the vias h formed in the connection conductor portion Jc) be equal to or lower than the resistivity of each of the first partial wiring U1 and the second partial wiring U2. In this embodiment, for example, two vias h are formed in one connection conductor portion Jc, and the resistivity of the connection conductor portion Jc including these two vias h is set to be lower than the resistivity of the first partial wiring U1 and the second partial wiring U2. As a result, the electrical resistance value of the connection conductor portion Jc including these two vias h is lower than the electrical resistance values ​​of the first partial wiring U1 and the second partial wiring U2.

[0047] Referring to FIG. 1, the other two continuous wirings Vc and Wc, which are connected to the external terminals Vp and Wp, respectively, and through which V-phase and W-phase currents flow, are configured in the same manner as the above-described U-phase continuous wiring Uc.

[0048] Specifically, the continuous wiring Vc through which a V-phase current flows includes a first continuous portion Vs1 and a second continuous portion Vs2 extending in the X direction, which is the longitudinal direction of the insulating sheet 11. The first continuous portion Vs1 is configured by alternately cascading first partial wirings V1a, V1c, V1e, V1g, V1i, and V1k formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings V2a, V2c, V2e, V2g, V2i, and V2k formed on the second main surface (front surface) of the insulating sheet 11 by vias h provided in the corresponding connecting conductor portions Jc.

[0049] In addition, the second continuous portion Vs2 is configured by alternately connecting in cascade the first partial wirings V1b, V1d, V1f, V1h, V1j, and V1m formed on the first main surface (back surface) of the insulating sheet 11 and the second partial wirings V2b, V2d, V2f, V2h, V2j, and V2m formed on the second main surface (front surface) of the insulating sheet 11 by vias h provided in the corresponding connecting conductor portions Jc.

[0050] Then, a continuous wiring Vc is formed that is electrically connected from the external terminal Vp to the first continuous portion Vs1, the inverted portion Vt, the second continuous portion Vs2, and the common connection portion Cc. Furthermore, when viewed in a projected plan view from the normal direction of the main surface of the insulating sheet 11, the first continuous portion Vs1 and the second continuous portion Vs2 intersect in a chain-like manner without being electrically conductive to each other, and the chain-like annular portions formed by this intersection each constitute a single coil.

[0051] Similarly, the continuous wiring through which the W-phase current flows includes a first continuous portion Ws1 and a second continuous portion Ws2 extending in the X direction, which is the longitudinal direction of the insulating sheet 11. The first continuous portion Ws1 is configured by alternately cascading first partial wirings W1a, W1c, W1e, W1g, W1i, and W1k formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings W2a, W2c, W2e, W2g, W2i, and W2k formed on the second main surface (front surface) of the insulating sheet 11 by vias h provided in the corresponding connecting conductor portions Jc.

[0052] In addition, the second continuous portion Ws2 is composed of first partial wirings W1b, W1d, W1f, W1h, W1j, and W1m formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings W2b, W2d, W2f, W2h, W2j, and W2m formed on the second main surface (front surface), which are alternately connected in cascade by vias h provided in the corresponding connecting conductor portions Jc.

[0053] Then, a continuous wiring Wc is formed that is electrically connected from the external terminal Wp to the first continuous portion Ws1, the inverted portion Wt, the second continuous portion Ws2, and the common connection portion Cc. Furthermore, the first continuous portion Ws1 and the second continuous portion Ws2 intersect in a chain-like manner when viewed in a projected plan view from the normal direction of the main surface of the insulating sheet 11, and the chain-like annular portions formed by this intersection each constitute a single coil.

[0054] The annular portions formed by the continuous wirings Vc and Wc correspond to the annular portion CR of the continuous wiring Uc described above, and therefore, hereinafter, the annular portions formed by the continuous wirings Vc and Wc will also be referred to as the annular portion CR.

[0055] In the following description, the first partial wirings V1a, V1b, V1c, V1d, V1e, V1f, V1g, V1h, V1i, V1j, V1k, and V1m will be collectively referred to as the first partial wiring V1. The second partial wirings V2a, V2b, V2c, V2d, V2e, V2f, V2g, V2h, V2i, V2j, V2k, and V2m will be collectively referred to as the second partial wiring V2. Similarly, the first partial wirings W1a, W1b, W1c, W1d, W1e, W1f, W1g, W1h, W1i, W1j, W1k, and W1m are collectively referred to as the first partial wiring W1. Furthermore, the second partial wirings W2a, W2b, W2c, W2d, W2e, W2f, W2g, W2h, W2i, W2j, W2k, and W2m are collectively referred to as the second partial wiring W2.

[0056] 1, the three continuous wirings Uc, Vc, and Wc are formed so that their positions are shifted from one another by a predetermined distance along the longitudinal direction (X direction) of the insulating sheet 11. In this embodiment, the predetermined distance is shorter than the length in the X direction of the annular portion CR that forms the coil in each continuous wiring, and the annular portions CR of the three continuous wirings Uc, Vc, and Wc overlap one another.

[0057] The flexible circuit board 10 having the above configuration has three continuous wirings Uc, Vc, and Wc formed on a single insulating sheet 11. In each of the continuous wirings Uc, Vc, and Wc, first continuous portions Us1, Vs1, and Ws1 and second continuous portions Us2, Vs2, and Ws2 intersect with each other in a chain shape without electrical continuity, forming a plurality of annular portions CR in a projected plan view seen from the normal direction to the main surface of the insulating sheet 11. In each of the continuous wirings Uc, Vc, and Wc, the plurality of annular portions CR form coils that are connected in series with each other and generate magnetic poles that are opposite to each other in adjacent annular portions.

[0058] That is, flexible circuit board 10 has coils connected in series to each other on insulating sheet 11 for each of the U, V, and W phases. Therefore, when using this to configure a motor stator, it is not necessary to bond two circuit boards together, connect multiple electrodes provided on the circuit boards to each other, or individually energize the coils on the circuit boards, as in the conventional method. Therefore, by using flexible circuit board 10, the stator manufacturing process can be simplified and the number of steps required to manufacture a motor can be reduced. Furthermore, since flexible circuit board 10 does not require the process of connecting individual coils as described above, it is possible to avoid motor malfunctions due to poor connections between the coils and improve the manufacturing quality of the motor.

[0059] Furthermore, in the flexible circuit board 10, the first continuous portions Us1, Vs1, and Ws1 and the second continuous portions Us2, Vs2, and Ws2 in each of the continuous wirings Uc, Vc, and Wc intersect with one another in a chain-like fashion to form multiple annular portions CR. This eliminates gaps between adjacent annular portions CR, making it easy to increase the arrangement density of the coils formed by these annular portions CR on the insulating sheet 11. Therefore, when a motor 20 is constructed using the flexible circuit board 10, the arrangement density of the stator slots in the stator 21 is increased. As a result, the length of the magnetic path formed by adjacent stator slots is shortened, reducing magnetic resistance, and therefore making it possible to reduce the wall thickness of the case 23 of the stator 21 accordingly. This allows for a reduction in the weight per volume of the motor 20.

[0060] Furthermore, in this embodiment, the first partial wirings U1, V1, W1 and the second partial wirings U2, V2, W2 that make up the continuous wirings Uc, Vc, Wc are connected to each other by vias h formed in connection conductors Jc that are arranged along the two long sides 12a and 12b of the insulating sheet 11. Moreover, the connection conductors Jc are formed to extend toward the nearest long side 12a or 12b, respectively.

[0061] As a result, in the flexible circuit board 10, heat generated by current flowing through the vias h connecting the first partial wirings U1, V1, and W1 and the second partial wirings U2, V2, and W2 is efficiently conducted to the vicinity of the long side 12a or 12b of the insulating sheet 11 via the conductor foil of the connecting conductor portion Jc. Therefore, when the flexible circuit board 10 is housed in the case 23 of the motor 20, the generated heat is efficiently dissipated from the long side 12a or 12b to the outside of the motor 20 via the outer peripheral wall of the case 23. As a result, a temperature rise in the portion of the soft magnetic case 23 that constitutes the stator slot together with the annular portion CR of the continuous wiring Uc, Vc, and Wc can be suppressed, and a decrease in magnetic susceptibility in that portion can be suppressed, thereby maintaining high operating performance of the motor 20 during continuous operation.

[0062] [1.2 Variations] Next, a modified example of the flexible circuit board 10 will be described. Fig. 6 is a diagram showing the configuration of a flexible circuit board 101 according to a modified example of the flexible circuit board 10, and corresponds to Fig. 2 described above, showing only the continuous wiring Uc to which the U phase is energized. For ease of explanation, Fig. 6 only shows the continuous wiring Uc of the U phase, but the continuous wirings Vc, Wc of the V phase and the W phase are configured in the same way. The continuous wirings Uc, Vc, Wc of the U phase, V phase, and W phase, respectively, are formed at positions offset from each other by a predetermined distance along the longitudinal direction (X direction) of the insulating sheet 11, similar to the configuration described above in Fig. 1.

[0063] In this modification, the continuous wiring Uc includes two first continuous portions Us11, Us12 and two second continuous portions Us21, Us22 that are parallel to each other and extend in one direction along the longitudinal direction of the insulating sheet 11. The first continuous portions Us11, Us12 and the second continuous portions Us21, Us22 are alternately connected in cascade, such as first continuous portion Us11 → second continuous portion Us21 → first continuous portion Us12 → second continuous portion US22. In addition, the two first continuous portions US11, Us12 and the two second continuous portions Us21, Us22 intersect in a chain shape without being electrically connected to each other in a planar perspective view seen from the direction normal to the main surface of the insulating sheet 11.

[0064] The two first continuous portions Us11 and Us12 are configured similarly to the first continuous portion Us1 in Fig. 2. The two second continuous portions Us21 and Us22 are configured similarly to the second continuous portion Us2 in Fig. 2. Specifically, the first continuous portion Us11 is composed of first partial wirings U11a, U11c, U11e, U11g, U11i, and U11k formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings U21a, U21c, U21e, U21g, U21i, and U21k formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0065] In addition, the first continuous portion Us12 is composed of first partial wirings U12a, U12c, U12e, U12g, U12i, and U12k formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings U22a, U22c, U22e, U22g, U22i, and U22k formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0066] In addition, the second continuous portion Us21 is composed of first partial wirings U11b, U11d, U11f, U11h, U11j, and U11m formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings U21b, U21d, U21f, U21h, U21j, and U21m formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0067] In addition, the second continuous portion Us22 is composed of first partial wirings U12b, U12d, U12f, U12h, U12j, and U12m formed on the first main surface (back surface) of the insulating sheet 11 and second partial wirings U22b, U22d, U22f, U22h, U212, and U22m formed on the second main surface (front surface), which are alternately connected in cascade by vias h.

[0068] Hereinafter, the first partial wirings U11a, U11b, U11c, U11d, U11e, U11f, U11g, U11h, U11i, U11j, U11k, and U11m will be collectively referred to as the first partial wiring U11. Furthermore, the first partial wirings U12a, U12b, U12c, U12d, U12e, U12f, U12g, U12h, U12i, U12j, U12k, and U12m will be collectively referred to as the first partial wiring U12.

[0069] The second partial wirings U21a, U21b, U21c, U21d, U21e, U21f, U21g, U21h, U21i, U21j, U21k, and U21m are also collectively referred to as the second partial wiring U21. The second partial wirings U22a, U22b, U22c, U22d, U22e, U22f, U22g, U22h, U22i, U22j, U22k, and U22m are also collectively referred to as the second partial wiring U22.

[0070] In FIG. 6, the two first continuous portions Us11 and Us12 and the two second continuous portions US21 and Us22 are alternately connected in cascade by the relay portion Ur on the left side of the figure and the inversion portions Ut1 and Ut2 on the right side of the figure.

[0071] Furthermore, the two first continuous portions Us11 and Us12 that are the first continuous portions and the two second continuous portions Us21 and Us22 that are the second continuous portions intersect in a chain shape in a planar perspective view seen from the direction normal to the main surface of the insulating sheet 11 to form a plurality of diamond-shaped annular portions CRw (annular portions surrounded by a double circle of partial wirings within the dotted line frame in the figure). The annular portion CRw shown in FIG. 6 equivalently forms a single coil, similar to the annular portion CR in FIG. 2. However, the annular portion CRw shown in FIG. 6 differs from the annular portion CR in FIG. 2 in that it is surrounded by a double diamond pattern formed by the first partial wirings U11 and U12 and the second partial wirings U21 and U22, respectively.

[0072] As a result, each coil formed by the diamond-shaped annular portion CRw corresponds to a coil with two turns, and a larger magnetic force can be generated compared to the coil formed by the annular portion CR shown in Figure 2.

[0073] [2. Second Embodiment] Next, a substrate stack 30 according to a second embodiment will be described. [2.1 Structure of the substrate laminate] 7 is a diagram showing the configuration of a substrate laminate 30. The substrate laminate 30 is formed by stacking a plurality of strip-shaped flexible circuit boards and bending them into a cylindrical shape. In this embodiment, the cylindrical substrate laminate 30 is formed by stacking four flexible circuit boards 31a, 31b, 31c, and 31d in this order from the inner periphery of the cylinder. Hereinafter, the flexible circuit boards 31a, 31b, 31c, and 31d will be collectively referred to as flexible circuit boards 31.

[0074] The substrate laminate 30 is used to form a stator of a rotating electric machine. The rotating electric machine in which the substrate laminate 30 is used is, for example, a motor 40, which is a three-phase brushless motor shown in Fig. 11. However, the rotating electric machine in which the substrate laminate 30 is used is not limited to a motor, and may be, for example, a generator configured similarly to the motor 40.

[0075] 11, the same components as those in motor 20 shown in Fig. 5 are designated by the same reference numerals as those in Fig. 5, and the above explanation of Fig. 5 is applicable. Motor 40 shown in Fig. 11 has a configuration similar to that of motor 20, but includes stator 41 instead of stator 21. Stator 41 is composed of case 42, which is a soft magnetic material processed into a cup-shaped cylinder, and substrate laminate 30 (the portion shown by hatching in Fig. 8) arranged along the inner periphery of case 42.

[0076] The four flexible circuit boards 31 can be assembled into the case 42 in order along the inner periphery thereof to form the substrate stack 30 shown in Fig. 7 as a whole. Alternatively, the four flexible circuit boards 31 may be stacked in advance and assembled into the substrate stack 30 shown in Fig. 7 before being assembled into the case 42.

[0077] [2.2 Flexible Circuit Board Structure] Next, the configuration of the flexible circuit board 31 that constitutes the substrate laminate 30 will be described. Fig. 8 is a diagram showing the configuration of a flexible circuit board 31. In Fig. 8, the same components as those in the flexible circuit board 10 shown in Fig. 1 are denoted by the same reference numerals as in Fig. 1, and the above description of Fig. 1 is incorporated herein.

[0078] 9 is a diagram showing only the continuous wiring Uc through which a U-phase current flows, of the three continuous wirings Uc, Vc, and Wc formed on the flexible circuit board 31 shown in FIG. 8, and corresponds to the above-mentioned FIG. 2. In FIG. 9, the same components as those in the flexible circuit board 10 shown in FIG. 2 are assigned the same reference numerals as in FIG. 2, and the explanation of FIG. 2 above is incorporated herein. In FIG. 8, the other two continuous wirings Vc and Wc, which are connected to the external terminals Vp and Wp, respectively, through which V-phase and W-phase currents flow, are also configured in the same manner as the U-phase continuous wiring Uc shown in FIG. 9.

[0079] 8 and 9, flexible circuit board 31 has the same configuration as flexible circuit board 10 described above with reference to Figures 1 and 2, but differs in that it has insulating sheet 32 ​​instead of insulating sheet 11. Insulating sheet 32 ​​has the same configuration as insulating sheet 11, but differs in that it has protrusions Tb on two long sides 33a and 33b of strip-shaped insulating sheet 32, protruding from long sides 33a and 33b toward the outside in the width direction of insulating sheet 32.

[0080] As shown in Figures 8 and 9, in the flexible circuit board 31, the vias h connecting the first partial wirings U1, V1, W1 and the second partial wirings U2, V2, W2 are provided in the connecting conductor portions Jc arranged along the long sides 33a and 33b, as in the flexible circuit board 10.

[0081] The protrusions Tb are used to align the relative positions of the multiple overlapping flexible circuit boards 31 when assembling the substrate laminate 30. Specifically, the multiple flexible circuit boards 31 are overlapped so that the positions of the protrusions Tb of each flexible circuit board 31 match (for example, so that the outer edges of the protrusions Tb match). Then, the overlapping multiple flexible circuit boards 31 are bent into a cylindrical shape so that both longitudinal ends of each flexible circuit board 31, i.e., short sides 33c and 33d, face each other, thereby forming the substrate laminate 30.

[0082] A groove for fitting the protrusion Tb of the flexible circuit board may be provided on the inner periphery of the case 42 of the motor 40 into which the substrate laminate 30 is incorporated.

[0083] 12 is a diagram showing an example of the configuration of the case 42. The case 42 has a ring-shaped protrusion 422 provided on the inner periphery of the inner bottom surface 421, and grooves 423 into which the protrusions Tb of the flexible circuit board 31 fit are provided in part of the protrusion 422, the number of which corresponds to the number of protrusions Tb of the flexible circuit board 31.

[0084] When assembling the flexible circuit boards 31 one by one into the case 42 of the case 42 and assembling the substrate stack 30 inside the case 42, the flexible circuit boards 31 arranged on the outer periphery of the substrate stack 30 can be assembled into the case 42 in order so that the protrusions Tb fit into the grooves 423.

[0085] The multiple flexible circuit boards 31 that make up the substrate laminate 30 are stacked so that the outer edges of the respective protrusions Tb are aligned, and therefore the wiring patterns such as the first continuous portion Us1 formed on each flexible circuit board 31 are stacked in the direction normal to the principal surface of the flexible circuit board 31. As a result, the annular portions CR formed by the respective continuous wirings formed on each flexible circuit board 31 are stacked on top of each other.

[0086] When the multiple flexible circuit boards 31 stacked in this manner are assembled into the motor 40, the external terminals Up, Vp, and Wp are connected to one another via terminals of a terminal block disposed on the outer wall of the case 42. As a result, the stacked annular portions constitute a laminated coil connected in parallel to one another.

[0087] 8, the protrusion Tb also has a heat conduction pattern 34 (hatched portion) formed using a material with a higher thermal conductivity than the material of the insulating sheet 32. In this embodiment, the heat conduction pattern is made of the same metal as the conductor patterns such as the first partial wiring U1. The metal is, for example, copper (Cu).

[0088] As a result, when the flexible circuit board 31 is incorporated into the motor 40 as part of the substrate laminate 30, the heat generated in the flexible circuit board 31 is transmitted from the heat conduction pattern 34 of the protrusion Tb to the case 42 and is dissipated from the outer surface of the case 42 to the outside of the motor 40.

[0089] In particular, in the flexible circuit board 31, vias h that easily generate heat are provided in the connection conductors Jc arranged along the long sides 33a and 33b, and protrusions Tb having heat conduction patterns 34 are provided on the long sides 33a and 33b. Therefore, when the flexible circuit board 31 is incorporated into the motor 40, the heat generated in the vias h is conducted along the connection conductors Jc in the direction of the long sides 33a and 33b, and then is quickly conducted from the protrusions Tb having the heat conduction patterns 34 to the case 42, where it is efficiently dissipated to the outside of the motor 40.

[0090] In this embodiment, three protrusions Tb are provided on each of the long sides 33a and 33b of the flexible circuit board 31, but the number and arrangement of the protrusions Tb are not limited to this. The number of protrusions Tb only needs to be at least one. Furthermore, the protrusions Tb may be arranged on one or both of the long sides 33a and 33b.

[0091] Inside the cylinder formed by the substrate laminate 30, the circumferential length increases as the distance from the central axis of the cylinder increases. For this reason, in this embodiment, the overall length Ls of the insulating sheet 32 ​​of the flexible circuit board 31 is varied depending on the position in the substrate laminate 30. As shown in FIG. 9 , the overall length Ls is the distance from the short side 33c to the short side 33d of the strip-shaped insulating sheet 32. Note that since the overall length of the insulating sheet 32 ​​is equivalent to the overall length of the flexible circuit board 31, hereinafter the overall length Ls of the insulating sheet 32 ​​will also be referred to as the overall length Ls of the flexible circuit board 31.

[0092] In this embodiment, in the substrate laminate 30, the flexible circuit boards 31 disposed farther from the central axis of the cylinder formed by the substrate laminate 30 have longer overall lengths Ls of their insulating sheets 32. As described above, in the substrate laminate 30 of this embodiment, the flexible circuit boards 31a, 31b, 31c, and 31d are disposed in this order from the inner periphery to the outer periphery (FIG. 7). Therefore, assuming that the overall lengths Ls of the flexible circuit boards 31a, 31b, 31c, and 31d are Lsa, Lsb, Lsc, and Lsd, respectively, these overall lengths are set to satisfy the relationship of the following formula (2). Lsa <Lsb<Lsc<Lsd (2)

[0093] Here, each of Lsa, Lsb, Lsc, and Lsd can be determined, for example, based on the radius from the central axis of a cylinder formed in a substrate stack 30 to the midpoint of the thickness of the corresponding flexible circuit board 31.

[0094] In addition, in this embodiment, the total length Ls of the insulating sheet 32 ​​is set longer for the flexible circuit board 31 that is arranged farther from the central axis of the cylinder formed by the substrate laminate 30, and accordingly, the distance measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​from one end of the longitudinal direction of the insulating sheet 32 ​​to the protrusion Tb is set longer for the flexible circuit board 31 that is arranged farther from the central axis.

[0095] For example, in Figure 9, the distance Lt measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​from the short side 33c, which is one end of the longitudinal direction of the insulating sheet 32, to the left end of the protrusion Tb formed on the left side of the long side 33a in the figure is set to be longer for flexible circuit boards 31 that are arranged farther from the central axis of the cylinder formed by the substrate laminate 30.

[0096] Specifically, if the distance Lt in the flexible circuit boards 31a, 31b, 31c, and 31d is Lta, Ltb, Ltc, and Ltd, respectively, the distances Ltb, Ltc, and Ltd in the flexible circuit boards 31b, 31c, and 31d are determined using the distance Lta in the flexible circuit board 31a as a reference using the following equations (3), (4), and (5). Ltb = Lta × Lsb / Lsa (3) Ltc = Lta × Lsc / Lsa (4) Ltd = Lta × Lsd / Lsa (5)

[0097] The positions of the other protrusions Tb are set in the same manner. As a result, when multiple flexible circuit boards 31 are stacked to form a cylindrical substrate laminate 30, the positions of the corresponding protrusions Tb of the multiple flexible circuit boards 31 on the cylinder can be matched to improve the matching accuracy of the multiple flexible circuit boards 31 in the substrate laminate 30 (including the matching accuracy of the entire outer edges between the insulating sheets 32 and the matching accuracy between corresponding partial wiring).

[0098] In addition, in this embodiment, for the multiple annular portions CR connected in a chain shape in each of the continuous wirings formed on the insulating sheet 32 ​​of the flexible circuit board 31, the distance measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​from one end of the longitudinal direction of the insulating sheet 32 ​​to each annular portion CR is set to be longer for the flexible circuit board 31 that is arranged farther from the central axis of the cylinder formed by the substrate laminate 30.

[0099] Furthermore, the length of the annular portion CR measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​of the flexible circuit board 31 is set to be longer as the flexible circuit board 31 is disposed farther from the central axis of the cylinder formed by the substrate laminate 30.

[0100] For example, in Figure 9, the distance Lr measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​from the short side 33c, which is one end of the longitudinal direction of the insulating sheet 32, to the left end of the diamond-shaped ring-shaped portion CR formed on the left side of the figure is set to be longer for flexible circuit boards 31 that are arranged farther from the central axis of the cylinder formed by the substrate laminate 30.

[0101] In addition, in Figure 9, for example, the length Lp measured along the longitudinal direction (X direction) of the insulating sheet 32 ​​from the left end to the right end of the diamond-shaped ring portion CR formed on the left side of the insulating sheet 32 ​​is set to be longer for flexible circuit boards 31 arranged farther from the central axis of the cylinder formed by the substrate laminate 30.

[0102] Specifically, if the distance Lr in the flexible circuit boards 31a, 31b, 31c, and 31d is represented by Lra, Lrb, Lrc, and Lrd, respectively, the distances Lrb, Lrc, and Lrd in the flexible circuit boards 31b, 31c, and 31d are determined using the distance Lra in the flexible circuit board 31a as a reference using the following equations (6), (7), and (8). Lrb = Lra × Lsb / Lsa (6) Lrc = Lra × Lsc / Lsa (7) Lrd = Lra × Lsd / Lsa (8)

[0103] Furthermore, if the lengths Lp of the annular portions of the flexible circuit boards 31a, 31b, 31c, and 31d are respectively Lpa, Lpb, Lpc, and Lpd, the lengths Lpb, Lpc, and Lpd of the flexible circuit boards 31b, 31c, and 31d are determined using the length Lpa of the flexible circuit board 31a as a reference using the following equations (9), (10), and (11). Lpb = Lpa × Lsb / Lsa (9) Lpc = Lpa × Lsc / Lsa (10) Lpd = Lpa × Lsd / Lsa (11)

[0104] The positions and lengths of all the looped portions of the U-phase, V-phase, and W-phase continuous wiring formed on the insulating sheet 32 ​​are set in the same manner as above.

[0105] As a result, when multiple flexible circuit boards 31 are stacked to form a cylindrical substrate laminate 30, the wiring that forms corresponding annular portions CR between the multiple flexible circuit boards 31 overlaps each other with high positional accuracy.

[0106] In this embodiment, the widths of all partial wirings, such as the first partial wiring U1 and the second partial wiring U2, that make up the continuous wiring formed on the insulating sheet 32 ​​of the flexible circuit board 31 are set to be larger as the flexible circuit board 31 is disposed farther from the central axis of the cylinder formed by the substrate laminate 30. The width of the partial wiring described above can be defined as a width wd3 along the longitudinal direction (X direction) of the insulating sheet 32, for example, as shown in FIG.

[0107] As an example, Fig. 12 is a cross-sectional view taken along the line XX in Fig. 7, illustrating a cross section of a portion where the portions where the second partial wirings U2a of multiple flexible circuit boards 31 overlap in the substrate laminate 30. In Fig. 12, the second partial wirings U2a of the flexible circuit boards 31a, 31b, 31c, and 31d are shown as second partial wirings U2aa, U2ab, U2ac, and U2ad, respectively. Furthermore, the widths w3 of the partial wirings of the flexible circuit boards 31a, 31b, 31c, and 31d are shown as widths w3a, w3b, w3c, and w3d.

[0108] As shown in the figure, in this embodiment, the widths w3b, w3c, and w3d of the flexible circuit boards 31b, 31c, and 31d are set to become wider in order from the width w3a of the innermost flexible circuit board 31a in the substrate stack 30 toward the periphery, that is, to the widths expressed by the following formula (12). W3a <w3b<w3c<w3d (11)

[0109] This makes it possible to increase the total cross-sectional area of ​​the second partial wiring U2a, through which the U-phase current flows, as compared to a configuration in which the widths W3a, w3b, w3c, and w3d are all the same, for the entire flexible circuit boards 31 that make up the substrate laminate 30. The same is true for partial wirings other than the second partial wiring U2a.

[0110] As a result, in the substrate laminate 30, the DC resistance of each of the continuous wiring Uc, Vc, and Wc of the U-phase, V-phase, and W-phase can be further reduced, thereby reducing the operating voltage of the motor 40 using the substrate laminate 30 and reducing power consumption.

[0111] [2.3 Modifications] Next, a modified example of the flexible circuit board 31 that constitutes the substrate laminate 30 according to the second embodiment will be described. [2.3.1 First Modification] Fig. 13 is a diagram showing the configuration of a flexible circuit board 311 according to a first modified example of the flexible circuit board 31. The flexible circuit board 311 can be used in the substrate laminate 30 in place of the flexible circuit board 31. Note that in Fig. 13, reference numerals relating to wiring such as the first partial wiring U1a are omitted.

[0112] The flexible circuit board 311 has a similar configuration to the flexible circuit board 31, but differs in that it has a heat conduction pattern 35 instead of the heat conduction pattern 34. The heat conduction pattern 35 has a similar configuration to the heat conduction pattern 34, but is formed to extend from the protrusion Tb to the long side 33a or 33b of the insulating sheet 11 on which the protrusion Tb is provided. The heat conduction pattern 35 extends, for example, on the long side 33a or 33b into the area where the connection conductor Jc is formed.

[0113] In the flexible circuit board 311, heat generated in the vias h of the connection conductors Jc can be efficiently conducted to the protrusions Tb, and can be more effectively dissipated through the case 42 of the motor 40.

[0114] [2.3.2 Second Modification] Fig. 14 is a diagram showing the configuration of a flexible circuit board 312 according to a second modified example of the flexible circuit board 31. The flexible circuit board 312 can be used in the substrate laminate 30 in place of the flexible circuit board 31. Note that in Fig. 14, reference numerals relating to wiring such as the first partial wiring U1a are omitted.

[0115] The flexible circuit board 312 has the same configuration as the flexible circuit board 31, but the protrusions Tb are not configured as part of the insulating sheet 32, but are configured from a material with higher thermal conductivity than the insulating sheet 32. Specifically, the protrusions Tb are configured from a heat conduction plate 36 that is separate from the insulating sheet 32 ​​and is configured from a material with high thermal conductivity (e.g., copper, aluminum, etc.). The heat conduction plate 36 is fixed to the long sides 33a and 33b of the insulating sheet 32 ​​by, for example, soldering or brazing.

[0116] According to this configuration, the entire protrusion Tb is made of a material with high thermal conductivity, so that heat generated in the vias h of the connection conductor Jc can be dissipated more effectively. [2.3.2 Third Modification] Fig. 15 is a diagram showing the configuration of a flexible circuit board 313 according to a third modified example of the flexible circuit board 31. The flexible circuit board 313 can be used in the substrate laminate 30 in place of the flexible circuit board 31. Note that in Fig. 15, reference numerals relating to wiring such as the first partial wiring U1a are omitted.

[0117] The flexible circuit board 313 has a similar configuration to the flexible circuit board 31, but differs in that it includes an outer edge plate 37 arranged along the long sides 33a and 33b of the insulating sheet 32 ​​and made of a material (e.g., copper, aluminum, etc.) with a higher thermal conductivity than the insulating sheet 32. The flexible circuit board 313 also differs from the flexible circuit board 31 in that the protrusions Tb are not configured as part of the insulating sheet 32 ​​but are part of the outer edge plate 37 that extends from the outer edge plate 37. The outer edge plate 37 extends, for example, on the long side 33a or 33b, over the range in which the connection conductors Jc are formed. The outer edge plate 37 is fixed to the long sides 33a and 33b of the insulating sheet 32 ​​by, for example, soldering or brazing.

[0118] According to this configuration, the protrusion portion Tb is configured as part of the outer edge plate 37 arranged along the long sides 33a and 33b and has a higher thermal conductivity than the insulating sheet 32, so that the heat generated in the via h of the connecting conductor portion Jc can be dissipated more effectively.

[0119] [3. Other embodiments] In the flexible circuit board 10 shown in the first embodiment described above, the U-phase, V-phase, and W-phase continuous wirings Uc, Vc, and Wc each form a diamond-shaped annular portion CR that is connected in a chain shape in a projected plan view seen from the normal direction of the main surface of the insulating sheet 11. However, the shape of the annular portion CR is not limited to a diamond and can be any shape. From the viewpoint of obtaining as large a magnetic force as possible in the coil formed by the annular portion CR, it is desirable that the shape of the annular portion CR has a large area of ​​the region enclosed by the annular portion CR.

[0120] For example, the annular portion CR may be a polygon such as a hexagon, or an ellipse or a circle. Such a shape of the annular portion CR can be realized by forming the shapes of the partial wirings, such as the first partial wiring U1, formed on each of the first and second main surfaces of the insulating sheet 11 into broken lines or curved lines. The same applies to the flexible circuit board 31 shown in the second embodiment.

[0121] The flexible circuit board 10 according to the first embodiment described above may be provided with protrusions Tb, similar to the flexible circuit board 31 according to the second embodiment. This allows, for example, the case 23 of the motor 20 to have a configuration similar to the case 42 shown in Fig. 11, so that the position of the flexible circuit board 10 inside the case 23 is determined by the protrusions Tb, and heat generated from the vias h of the connection conductors Jc can be efficiently dissipated.

[0122] In the first and second embodiments described above, as an example, the flexible circuit board 10 and the substrate laminate 30 are used in three-layer brushless motors, motors 20 and 40, respectively. However, the motors 20 and 40 are merely examples, and the flexible circuit board 10 and the substrate laminate 30 can also be used in generators having the same configuration as the motors 20 and 40.

[0123] Furthermore, the flexible circuit board 10 according to the first embodiment and the flexible circuit board 31 according to the second embodiment have three continuous wirings through which currents of three phases, U, V, and W, respectively, are passed. However, the number of continuous wirings is not limited to three. Depending on the number of operating phases of the rotating electrical machine to which the flexible circuit board 10 or the substrate laminate 30 is applied, the flexible circuit boards 10 and 31 may have continuous wirings of a number other than three.

[0124] 4. Configurations supported by the above embodiments The above-described embodiment and modifications support the following configurations.

[0125] (Configuration 1) A substrate laminate constructed by stacking a plurality of strip-shaped flexible circuit boards bent into a cylindrical shape in the radial direction of the cylinder, wherein each of the plurality of flexible circuit boards includes a strip-shaped insulating sheet and at least one continuous wiring formed on the insulating sheet, the continuous wiring including a first continuous portion and a second continuous portion extending in the longitudinal direction of the insulating sheet, the first continuous portion and the second continuous portion being formed by alternately connecting in tandem a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet through vias, the first continuous portion and the second continuous portion intersecting in a chain-like manner without being electrically connected to each other in a projected plan view seen from the normal direction to the main surface of the insulating sheet, forming a plurality of annular portions connected in a chain-like manner, and the length of the insulating sheet of the plurality of flexible circuit boards being longer as the flexible circuit boards are arranged farther from the central axis of the cylinder. According to the substrate laminate of Configuration 1, the longitudinal ends of the flexible circuit boards stacked and rolled into a cylinder can be aligned, allowing for accurate stacking of complex circuit patterns, such as loops of continuous wiring formed on each flexible circuit board. As a result, the strength of the magnetic field generated by the coil formed by the entire stack of loops can be increased, contributing to the realization of a rotating electric machine with high energy efficiency.

[0126] (Configuration 2) A substrate laminate according to Configuration 1, wherein each of the plurality of flexible circuit boards has at least one protrusion disposed on at least one of two long sides extending in the longitudinal direction of the insulating sheet, protruding from the long side toward the outside of the insulating sheet, and the flexible circuit boards disposed farther from the central axis of the cylinder have a longer distance measured along the longitudinal direction of the insulating sheet from one end of the longitudinal direction of the insulating sheet to the protrusion. According to the substrate laminate of Configuration 2, by aligning the positions of the protrusions of the flexible circuit boards stacked and rolled into a cylinder, the positions of the flexible circuit boards can be easily aligned with each other, thereby enabling complex circuit patterns, such as loops of continuous wiring that can form coils, formed on the flexible circuit boards to be stacked with greater precision.

[0127] (Configuration 3) A substrate laminate according to configuration 1 or 2, wherein the length of the chain-like annular portions of the flexible circuit boards measured along the longitudinal direction of the insulating sheet is longer for the flexible circuit boards arranged farther from the central axis of the cylinder. According to the substrate laminate of Configuration 3, the looped portions of the continuous wiring that can form the coil, which are formed on the respective flexible circuit boards, can be overlapped with even greater precision.

[0128] (Configuration 4) A substrate stack described in any one of configurations 1 to 3, wherein the width of the partial wiring that constitutes the continuous wiring is wider in the flexible circuit boards that are arranged farther from the central axis of the cylinder. According to the substrate laminate of configuration 4, the conductor cross-sectional area of ​​the coil that can be formed by the overlapping annular portions formed by stacking multiple flexible circuit boards can be made larger, thereby reducing the DC resistance of the coil and reducing power consumption.

[0129] (Configuration 5) A substrate laminate according to any one of configurations 1 to 4, wherein each of the plurality of flexible circuit boards has a plurality of the continuous wirings formed at offset positions relative to each other along the longitudinal direction of the insulating sheet. According to the substrate laminate of Configuration 5, a highly energy-efficient multi-phase AC rotating electric machine can be realized.

[0130] (Configuration 6) A rotating electric machine having a stator including the substrate laminate according to Configuration 5, and a rotor disposed inside a cylinder formed by the substrate laminate. According to the rotating electric machine of configuration 6, it is possible to provide a rotating electric machine that is lightweight and has improved energy efficiency. [Explanation of symbols]

[0131] 10, 101, 31, 31a, 31b, 31c, 31d, 311, 312, 313...flexible circuit board, 11, 32...insulating sheet, 12a, 12b, 33a, 33b...long side, 12c, 12d, 33c, 33d...short side, 20, 40...motor, 21, 41...stator, 22...rotor, 23, 42...case, 24...rotating body, 25...permanent magnet, 30...substrate laminate, 34, 35...heat conduction pattern, 36...heat conduction plate, 37...outer edge plate, 421...inner bottom surface, 422...protrusion, 423...groove, h...via, Jc...connecting conductor portion, Tb...protrusion, U1, U1a, U1b, U1c, U1d, U1e, U1f, U1g, U1h, U1i, U1j, U1k, U1m...U-phase first partial wiring, V1, V1a, V1b, V1c, V1d, V1e, V1f, V1g, V1h, V1i, V1j, V1k, V1m...V-phase first partial wiring, W1, W1a, W1b, W1c, W1d, W1e, W1f, W1g, W1h, W1i, W1j, W1k, W1m...W-phase first partial wiring, U2, U2a, U2b, U2c, U2d, U2e, U2f, U2g, U2h, U2i, U2j, U2k, U2m...U-phase second partial wiring, V2, V2a, V2b, V2c, V2d, V2 e, V2f, V2g, V2h, V2i, V2j, V2k, V2m...second partial wiring of V phase, W2, W2a, W2b, W2c, W2d, W2e, W2f, W2g, W2h, W2i, W2j, W2k, W2m...second partial wiring of W phase, Uc...continuous wiring of U phase, Vc...continuous wiring of V phase, Wc...continuous wiring of W phase, Us1...first continuous portion of continuous wiring of U phase, Vs1...first continuous portion of continuous wiring of V phase, Ws1...first continuous portion of continuous wiring of W phase, Us2...second continuous portion of continuous wiring of U phase, Vs2...second continuous portion of continuous wiring of V phase, Ws2...second continuous portion of continuous wiring of W phase, Ut ...U phase inversion part, Vt...V phase inversion part, Wt...W phase inversion part, Up...U phase external terminal, Vp...V phase external terminal, Wp...W phase external terminal, Cc...common connection part, U11, U11a, U12b, U11c, U11d, U11e, U11f, U11g, U12h, U11i, U11j, U11k, U11m, U12, U12a, U12b, U12c, U12d, U12e, U12f, U12g, U12h, U12i, U12j, U12k, U12m...U phase double first partial wiring, U21, U21a, U21b, U21c, U21d, U21e, U21f, U21g,U21h, U21i, U21j, U21j, U21m, U22, U22a, U22b, U22c, U22d, U22e, U22f, U22g, U22h, U22i, U22j, U22k, U22m... U-phase double second partial wiring, Us11, Us12... U-phase double first continuous portion of continuous wiring, Us21, Us22... U-phase double second continuous portion of continuous wiring, Ut1, Ut2... U-phase double inverted portion.

Claims

1. A substrate laminate constructed by stacking a plurality of strip-shaped flexible circuit boards bent into a cylindrical shape in a radial direction of the cylinder, Each of the flexible circuit boards includes a strip-shaped insulating sheet and at least one continuous wiring formed on the insulating sheet, The continuous wiring is a first continuous portion and a second continuous portion extending in a longitudinal direction of the insulating sheet, the first continuous portion and the second continuous portion being formed by alternately connecting a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet in cascade connection through vias; the first continuous portion and the second continuous portion intersect in a chain-like manner without being electrically connected to each other in a projected plan view seen from a normal direction to a main surface of the insulating sheet, to form a plurality of annular portions connected in a chain-like manner, The length of the insulating sheet of the flexible circuit boards is longer in the flexible circuit boards disposed farther from the central axis of the cylinder. Substrate stack.

2. Each of the flexible circuit boards has at least one protrusion disposed on at least one of two long sides extending in a longitudinal direction of the insulating sheet and protruding from the long side toward an outside of the insulating sheet, The flexible circuit boards arranged farther from the central axis of the cylinder have a longer distance measured along the longitudinal direction of the insulating sheet from one end of the insulating sheet in the longitudinal direction to the protrusion. The substrate laminate of claim 1 .

3. The flexible circuit boards arranged farther from the central axis of the cylinder have a longer length of the annular portions connected in a chain shape as measured along the longitudinal direction of the insulating sheet. The substrate laminate of claim 1 .

4. The flexible circuit boards, which are arranged farther from the central axis of the cylinder, have a larger width of the partial wiring that constitutes the continuous wiring. The substrate laminate of claim 1 .

5. Each of the plurality of flexible circuit boards includes a plurality of the continuous wirings formed at positions offset from each other along the longitudinal direction of the insulating sheet. The substrate laminate according to claim 1 .

6. A stator comprising the substrate laminate according to claim 5; a rotor disposed inside a cylinder formed by the substrate laminate; A rotating electric motor having

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