Substrate laminate, rotating electric machine, and flexible circuit board

Abstract

To provide a flexible circuit board capable of dissipating heat efficiently while reducing weight of a rotating electric 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 a band-shaped insulating sheet, a plurality of pieces of partial wiring formed on each of two main surfaces of the insulating sheet, and a protruding portion disposed on a long side extending in a longitudinal direction of the band-shaped insulating sheet, and the protruding portion is provided at a position where the pieces of corresponding partial wiring between the plurality of flexible circuit boards overlap each other when the plurality of flexible circuit boards is stacked such that the positions of the protruding portions thereof match with each other.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a substrate laminate, a rotating electric machine using the same, and a flexible circuit board that constitutes the substrate laminate. [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 in order to reduce CO2 emissions and improve energy efficiency.

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

[0004] Patent Document 2 discloses a motor in which teeth that become 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 sheet and the second sheet. The first sheet substrate is folded into a concave shape and fitted onto the teeth, and then the first sheet substrate and the second sheet substrate are stacked facing each other 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 dog-leg shaped group of parallel conductor wires formed on one side, and metal conductor protrusion array groups are exposed from both ends of each group of parallel conductor wires toward the outside of the board. Two flexible circuit boards are stacked in opposite directions and wound into a cylindrical shape, and the opposing groups of metal conductor protrusion arrays are joined, whereby the conductor wires of the two parallel conductor wire groups of the two flexible circuit boards are connected to form a coil. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-067756 A [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] In the technology for reducing the weight of motors, it is important to improve the performance of the stator coil made of a flexible circuit board to realize a motor with high energy efficiency. This is a common problem for rotating electrical machines, including generators that have a similar structure to motors. In order to solve the above 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, each of the plurality of flexible circuit boards including a strip-shaped insulating sheet and a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet, each of the plurality of flexible circuit boards having at least one protrusion arranged on at least one of two long sides extending in the longitudinal direction of the strip-shaped insulating sheet and protruding from the long side toward an outside of the insulating sheet, each of the protrusions of the flexible circuit boards being positioned such that corresponding partial wirings overlap between the plurality of flexible circuit boards when the plurality of flexible circuit boards are stacked so that the positions of corresponding protrusions of the flexible circuit boards coincide. According to another aspect of the present invention, the protruding portion of the flexible circuit board is provided with a heat transfer pattern made of a material having a higher thermal conductivity than the insulating sheet. According to another aspect of the present invention, the heat transfer pattern is formed extending from the protrusion to a long side of the insulating sheet. According to another aspect of the present invention, the protrusion of the flexible circuit board is made of a material having a higher thermal conductivity than the insulating sheet. According to another aspect of the present invention, the flexible circuit board has an outer edge plate arranged along the long side of the insulating sheet and made of a material having a higher thermal conductivity than the insulating sheet, and the protrusion portion is a part of the outer edge plate extending from the outer edge plate. According to another aspect of the present invention, the protrusions of the flexible circuit board are disposed on both of the two long sides of the insulating sheet. According to another aspect of the present invention, each of the multiple flexible circuit boards includes at least one continuous wiring formed on the insulating sheet, and the continuous wiring includes a first continuous portion and a second continuous portion extending in the longitudinal direction of the insulating sheet, which are formed by alternately connecting in cascade vias the multiple partial wirings formed on each of the two opposing main surfaces of the insulating sheet. According to another aspect of the present invention, in each of the multiple flexible circuit boards, the first continuous portion and the second continuous portion intersect in a chain-like manner without being conductive to each other in a projected plan view seen from the direction normal to the main surface of the insulating sheet, forming multiple annular portions connected in a chain-like manner, and each of the annular portions forms a coil. 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 each other 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. Another aspect of the present invention is a flexible circuit board that constitutes the substrate laminate, comprising a band-shaped insulating sheet, a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet, and at least one protrusion arranged on at least one of two long sides extending in the longitudinal direction of the band-shaped insulating sheet, protruding from the long side toward the outside of the insulating sheet. Effect 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 description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration of a flexible circuit board according to a first embodiment. [Diagram 2] For the sake of explanation, FIG. 2 shows only the continuous wiring of the U phase in the flexible circuit board shown in FIG. 1, with other continuous wirings omitted. [Diagram 3] 3 is a partial detailed view of the portion 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 a connection between partial wirings through a via. [Diagram 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 a 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 laminate according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing the configuration of a flexible circuit board that constitutes the board 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, with other continuous wirings omitted. [Figure 10] FIG. 10 is a cross-sectional view of the substrate laminate shown in FIG. [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 a configuration of a flexible circuit board according to a first modified example of the second embodiment. [Figure 14] FIG. 14 is a diagram showing a configuration of a flexible circuit board according to a second modified example of the second embodiment. [Figure 15] FIG. 15 is a diagram showing a configuration of a flexible circuit board according to a third modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the above-mentioned conventional technology, a process of connecting the coil patterns of the flexible circuit boards to each other after stacking multiple flexible circuit boards on which coil patterns are formed is required, which is disadvantageous in that the manufacturing process becomes complicated and the structure of the stator becomes complicated. In addition, in the conventional configuration, the connection parts between the coil patterns are easily heated due to discontinuity in electrical resistance compared to other conductor parts due to the use of a material (e.g., welding material or conductive paste) different from that of the coil patterns or due to variations in the connection area caused by misalignment between the coil patterns in the manufacturing process. The heat generated in such connection parts increases the temperature of the stator core around the coil patterns, reducing the magnetic susceptibility of the stator core and may cause deterioration of 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 configure 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 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 which is a soft magnetic material processed into a cylindrical cup shape, and a flexible circuit board 10 (the part shown by hatching in Fig. 5) which is arranged along the inner circumference of the case 23. As will be described later, wiring which constitutes a coil is formed on the flexible circuit board 10. The rotor 22 is composed of a rotating body 24 which is a magnetic material processed into a cylindrical cup shape, and a plurality of permanent magnets 25 which are attached or embedded on the outer circumference of the rotating body 24.

[0015] By using the flexible circuit board 10 constituting the coil for the stator 21, the weight of the stator can be reduced compared to a typical stator having a coil formed by winding a conductor. The stator 21 may be arranged on the inner periphery of the rotor 22.

[0016] 1, the flexible circuit board 10 has a flexible, band-shaped insulating sheet 11 extending left and right in the figure, and a first partial wiring U1, a second partial wiring U2, etc. (described later) which are a plurality of conductor patterns formed on two opposing main surfaces of the insulating sheet 11. The partial wirings formed on the two main surfaces are alternately connected in series through vias to form three independent continuous wirings Uc, Vc, Wc. Line currents (hereinafter simply referred to as currents) of the U-phase, V-phase, and W-phase of three-phase AC are passed through the three continuous wirings Uc, Vc, 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, which 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 shape without being electrically connected to each other in a projected plan view (for example, the plan view shown in FIG. 1) seen from the normal direction of the main surface of the insulating sheet 11. In each of the continuous wirings Uc, Vc, and Wc, each of a plurality of annular portions connected in a chain shape formed by the first continuous portion Us1, Vs1, and Ws1 intersecting with the second continuous portion Us2, Vs2, and Ws in a chain shape forms one 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 pattern formed on the first main surface (back surface) is shown by dashed lines, and the conductor pattern formed on the second main surface (front surface) is shown by solid lines. The same 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 shown in the figure, is the X direction (the rightward direction shown in the figure is the +X direction), and the vertical direction shown in the figure, that is, the width direction of the insulating sheet 11 perpendicular to the X direction, is the Y direction (the upward direction shown in the figure 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 sides 12c and 12d face each other, and is placed in the case 23. The inner surface side 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 is a diagram illustrating 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 illustrated X-direction, which is the longitudinal direction of the insulating sheet 11. The first continuous portion Us1 is configured by alternately cascading first partial wirings U1a, U1c, U1e, U1g, U1i, and U1k formed on the first main surface (rear surface) of the insulating sheet 11 and second partial wirings U2a, U2c, U2e, U2g, U2i, and U2k formed on the second main surface (front surface) of the insulating sheet 11 through 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. Also, 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 parts Jc extending from the ends of the adjacent first partial wiring U1 and second partial wiring U2 toward the nearest long sides 12a and 12b, respectively. Note that, although the reference symbol h is given to only the via of the connection conductor part Jc in the upper left corner of the figure in Fig. 2, it should be understood that similar vias are provided in the other connection conductor parts Jc.

[0028] One end (the end on the left side in FIG. 1) of the first continuous portion Us1 is connected to an external terminal Up to which a U-phase current is input. The other end (the end on the right side in FIG. 1) of the first continuous portion Us1 and one end (the end on the right side in FIG. 1) of the second continuous portion Us2 are connected in cascade via a conductor pattern constituting the inversion portion Ut and are electrically connected. The other end (the end on the left side in FIG. 1) of the second continuous portion is connected to a conductor pattern constituting the common connection portion Cc. The ends of continuous wiring Vc, Wc through which V-phase and W-phase currents described later are conducted are also connected to the common connection portion Cc (see FIG. 1). By connecting in this manner, a continuous wiring Uc is formed that is electrically connected from the external terminal Up to the first continuous portion Us1 to the inversion 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. 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 shape 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 (the normal direction to the paper surface in Figs. 1 and 2) (i.e., the intersection of the first continuous portion Us1 and the second continuous portion Us2 is insulated by the insulating sheet 11 and is not electrically connected). Each of the diamond-shaped ring-shaped portions CR (more specifically, the ring-shaped portions shown within the dotted-chain line frame in Fig. 2) formed by the intersection of the first continuous portion Us1 and the second continuous portion Us2 constitutes one coil. Note that in Fig. 2, only the ring-shaped portion on the left side of the figure is denoted by the symbol CR, but it should be understood that each of the ring-shaped portions having the same diamond shape and connected in the horizontal direction of the figure is the ring-shaped portion CR.

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

[0032] For the purpose of explanation, in Fig. 2, as an example, the direction of the U-phase current flowing in from the external terminal Up is shown by a dotted or solid straight arrow near each of 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, which is 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 the current flows counterclockwise as shown 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] In addition, the second diamond-shaped annular portion CR from the left in the figure, which is formed by the first partial wiring U1c and the second partial wiring U2c constituting the first continuous portion Us1 and the first partial wiring U1d and the second partial wiring U2b constituting the second continuous portion Us2, forms an equivalent coil in which a current flows clockwise as indicated by the circular thick arrow, thereby generating 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 inverted from each other. In addition, the magnetic field of each coil is inverted by reversing the direction of the U-phase current flowing through the external terminal Up, thereby generating an alternating magnetic field.

[0035] The coils each constituted by the annular portions CR form 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 constitute ten U-phase stator slots.

[0036] In this embodiment, the two ends of each 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 in a chain shape spreads over almost the entire width of the insulating sheet 11, and a large area can be secured for each, thereby generating a large magnetic force.

[0037] In this embodiment, particularly, the vias h that alternately connect the first partial wiring U1 and the second partial wiring U2 are arranged in the connection conductor portion Jc that extends from each of the ends of the first partial wiring U1 and 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 portion Jc is 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 manner 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 shown 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 shown in the figure 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 (portion drawn by a solid line in the figure) extends 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, a distance Lc. Similarly, the portion of the connecting conductor Jc formed on the first main surface (back surface) of the insulating sheet 11 (portion drawn by a dotted line in the figure) extends from the end of the first partial wiring U1a toward the long side 12a of the insulating sheet, a distance Lc. 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 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 connection 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 figure) connecting the first partial wiring U1a and the second partial wiring U2a is rapidly conducted through the conductor foil of the connection conductor portion Jc to the vicinity of the long side 12a of the insulating sheet 11. 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 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 value larger than wd1. As a result, the diameter r1 of the circular via h formed in the connection conductor portion Jc can be set to be larger than the diameter r2 of the via v formed in the simple overlapping portion of two conductor patterns Cp1, Cp2 having a line width wd1 as shown in Fig. 4. Therefore, in the flexible circuit board 10, the electrical resistance in the via h can be made smaller than that of the via v having the configuration shown in Fig. 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 via v is formed is limited to the intersection of the two linear conductor patterns Cp1, Cp2, whereas in the flexible circuit board 10, the connection conductor Jc can easily secure a large area in which the via h can be formed by increasing the extension distance Lc. Therefore, in the flexible circuit board 10, multiple vias h can be formed in one connection conductor Jc, thereby lowering the electrical resistance of the entire connection conductor Jc including the multiple vias h, and further reducing the heat generated in the connection conductor Jc.

[0045] When 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 is 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 the length of the end of the first partial wiring U1a corresponding to wd2 is its longitudinal width, and the connection conductor Jc formed on the second main surface may be formed so that the length of the end of the second partial wiring U2a corresponding to wd2 is its longitudinal width.

[0046] Here, from the viewpoint of reducing heat generation in the connection conductor portion Jc, it is desirable that the electrical resistance per area 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) is 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 the two vias h is set to be smaller 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 the two vias h is smaller 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 similarly to the above-mentioned 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 illustrated 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 (rear 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 connection 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 (rear 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 which 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 the intersections 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 illustrated 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 (rear 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 connection conductor portions Jc.

[0052] In addition, the second continuous portion Ws2 is configured by alternately connecting in cascade the first partial wirings W1b, W1d, W1f, W1h, W1j, and W1m formed on the first main surface (rear surface) of the insulating sheet 11 and the second partial wirings W2b, W2d, W2f, W2h, W2j, and W2m formed on the second main surface (front surface) of the insulating sheet 11 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. In addition, 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 the intersection each constitute a single coil.

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

[0055] In the following, the first partial wirings V1a, V1b, V1c, V1d, V1e, V1f, V1g, V1h, V1i, V1j, V1k, and V1m are 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 are 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. Also, 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 as to be 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-mentioned configuration has three continuous wirings Uc, Vc, and Wc formed on one insulating sheet 11. In the continuous wirings Uc, Vc, and Wc, first continuous portions Us1, Vs1, and Ws1 and second continuous portions Us2, Vs2, and Ws2 cross each other in a chain shape 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 to form a plurality of annular portions CR. 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 inverted with each other in adjacent annular portions.

[0058] That is, the flexible circuit board 10 has coils connected in series to each other on the insulating sheet 11 for each of the U, V, and W phases, so that when using the flexible circuit board 10 to configure a stator for a motor, it is not necessary to bond two circuit boards together, connect multiple electrodes provided on the circuit boards to each other, or pass current individually through the coils on the circuit boards, as in the past. Therefore, by using the flexible circuit board 10, the manufacturing process for the stator can be simplified and the number of manufacturing steps for the motor can be reduced. In addition, the flexible circuit board 10 does not require the process of connecting the individual coils as described above, so that the occurrence of malfunctions in the motor due to poor connections between the coils can be avoided, and the manufacturing quality of the motor can be improved.

[0059] In the flexible circuit board 10, the first continuous parts Us1, Vs1, and Ws1 and the second continuous parts Us2, Vs2, and Ws2 in each of the continuous wirings Uc, Vc, and Wc intersect with each other in a chain shape to form a plurality of annular parts CR. Since there is no gap between adjacent annular parts CR, the arrangement density of the coils formed by these annular parts CR on the insulating sheet 11 can be easily increased. Therefore, when the 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 the adjacent stator slots is shortened and the magnetic resistance is reduced, so that the wall thickness of the case 23 of the stator 21 can be made thinner. This allows the weight per volume of the motor 20 to be reduced.

[0060] Furthermore, in this embodiment, the first partial wirings U1, V1, W1 and the second partial wirings U2, V2, W2 constituting the continuous wirings Uc, Vc, Wc are connected to each other by vias h formed in the connection conductors Jc 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.

[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, W1 and the second partial wirings U2, V2, W2 is efficiently conducted to the vicinity of the long side 12a or 12b of the insulating sheet 11 through the conductor foil of the connection conductor 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 through the outer peripheral wall of the case 23. As a result, the temperature rise of the part of the soft magnetic case 23 that constitutes the stator slot together with the annular part CR of the continuous wiring Uc, Vc, Wc can be suppressed, and the decrease in magnetic susceptibility of the part can be suppressed, so that the operating performance of the motor 20 during continuous operation can be maintained high.

[0062] [1.2 Modifications] 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, which shows only the continuous wiring Uc through which the U phase is energized. For ease of explanation, Fig. 6 shows only the continuous wiring Uc of the U phase, but the continuous wirings Vc and Wc of the V phase and W phase are configured in the same manner. The continuous wirings Uc, Vc, and Wc of the U phase, V phase, and W phase are formed at positions shifted 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 the first continuous portion Us11 → the second continuous portion Us21 → the first continuous portion Us12 → the second continuous portion US22. The two first continuous portions US11, Us12 and the two second continuous portions Us21, Us22 cross each other in a chain shape without being electrically connected to each other in a planar perspective shape seen from the normal direction of 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 configured by first partial wirings U11a, U11c, U11e, U11g, U11i, and U11k formed on the first main surface (rear 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 (rear 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 (rear 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 (rear 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. Also, 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 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 collectively referred to as the second partial wiring U22.

[0070] In FIG. 6, the two first continuous portions Us11, Us12 and the two second continuous portions US21, 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] In addition, the two first continuous portions Us11 and Us12, which are the first continuous portion, and the two second continuous portions Us21 and Us22, which are the second continuous portions, intersect in a chain shape in a planar perspective shape seen from the normal direction of the main surface of the insulating sheet 11 to form a plurality of diamond-shaped ring portions CRw (ring portions surrounded by a double portion of partial wiring within the dotted line frame in the figure). The ring portion CRw shown in FIG. 6 equivalently forms one coil, similar to the ring portion CR in FIG. 2. However, the ring portion CRw shown in FIG. 6 differs from the ring 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 having two turns, and a larger magnetic force can be generated compared to the coil formed by the annular portion CR shown in FIG.

[0073] [2. Second embodiment] Next, a substrate laminate 30 according to a second embodiment will be described. [2.1 Structure of the substrate laminate] 7 is a diagram showing the configuration of the 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 circumference of the cylinder. Hereinafter, the flexible circuit boards 31a, 31b, 31c, and 31d are collectively referred to as flexible circuit boards 31.

[0074] The substrate laminate 30 is used to configure 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] In Fig. 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 description of Fig. 5 is incorporated herein. Motor 40 shown in Fig. 11 has a similar configuration to 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 cylindrical shape, and substrate laminate 30 (the portion shown by hatching in Fig. 8) disposed 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 Structure of flexible circuit board] Next, the configuration of the flexible circuit board 31 that constitutes the board 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 among the three continuous wirings Uc, Vc, and Wc formed on the flexible circuit board 31 shown in FIG. 8, and corresponds to FIG. 2 described above. In FIG. 9, the same components as those in the flexible circuit board 10 shown in FIG. 2 are denoted by the same reference numerals as in FIG. 2, and the explanation of FIG. 2 described 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 two long sides 33a and 33b of strip-shaped insulating sheet 32 ​​have protrusions Tb that protrude 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 connection 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 such that the positions of the protrusions Tb of each flexible circuit board 31 match (for example, such that the outer edges of the protrusions Tb match). Then, the overlapping multiple flexible circuit boards 31 are bent into a cylindrical shape such that both ends in the longitudinal direction of each flexible circuit board 31, i.e., the short sides 33c and 33d, face each other, to form 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 board laminate 30 is assembled.

[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 circumference 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 the 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 building up the substrate laminate 30 inside the case 42, the flexible circuit boards 31 arranged on the outer periphery of the substrate laminate 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 constituting the substrate laminate 30 are overlapped so that the outer edges of the respective protrusions Tb coincide with each other, and therefore the wiring patterns such as the first continuous portion Us1 formed on each flexible circuit board 31 are overlapped in the normal direction 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 in a state where the corresponding annular portions CR are stacked on top of each other.

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

[0087] 8, the protrusion Tb also has a heat conduction pattern 34 (hatched portion) formed using a material having a higher thermal conductivity than the material of the insulating sheet 32. In this embodiment, the heat conduction pattern is made of, for example, the same metal as the conductor patterns of the first partial wiring U1, etc. 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, heat generated in the flexible circuit board 31 is transmitted from the thermal conduction pattern 34 of the protrusion portion 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 tend to 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, heat generated in the vias h is conducted along the connection conductors Jc in the direction of the long sides 33a and 33b, and is then 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 may be at least one. 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 made different 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. 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 ​​is also 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 a longer total length Ls of the insulating sheet 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 circumference to the outer circumference (FIG. 7). Therefore, assuming that the total lengths Ls of the flexible circuit boards 31a, 31b, 31c, and 31d are Lsa, Lsb, Lsc, and Lsd, respectively, these total 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 the 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 longitudinal end of the insulating sheet 32 ​​to the protrusion portion Tb is set longer for the flexible circuit board 31 that is arranged farther from the central axis.

[0095] For example, in FIG. 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 portion Tb formed on the left side of the long side 33a in the figure is set to be longer for the flexible circuit board 31 that is disposed farther from the central axis of the cylinder formed by the substrate laminate 30.

[0096] Specifically, assuming that 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 a similar manner. As a result, when multiple flexible circuit boards 31 are stacked to form a cylindrical substrate laminate 30, the positions of corresponding protrusion portions Tb of the multiple flexible circuit boards 31 in the cylinder can be aligned to improve the alignment accuracy of the multiple flexible circuit boards 31 in the substrate laminate 30 (including the alignment accuracy of the entire outer edges between the insulating sheets 32, and the alignment accuracy between corresponding partial wiring).

[0098] In addition, in this embodiment, for the multiple chain-like ring-shaped portions CR 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 longitudinal end of the insulating sheet 32 ​​to each ring-shaped portion CR is set to be longer for the flexible circuit board 31 that is disposed 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 ​​is set to be longer for the flexible circuit board 31 disposed farther from the central axis of the cylinder formed by the board 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 FIG. 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 annular portion CR formed on the left side of the insulating sheet 32 ​​is set to be longer for the flexible circuit board 31 disposed 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 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 in the flexible circuit boards 31a, 31b, 31c, and 31d are Lpa, Lpb, Lpc, and Lpd, respectively, 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 in each of the U-phase, V-phase, and W-phase continuous wirings 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 constitutes corresponding annular portions CR between the multiple flexible circuit boards 31 overlaps with 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 constituting 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, showing a cross section of a portion where the second partial wirings U2a of the multiple flexible circuit boards 31 overlap in the board laminate 30. In Fig. 12, the second partial wirings U2a in the flexible circuit boards 31a, 31b, 31c, and 31d are shown as second partial wirings U2aa, U2ab, U2ac, and U2ad, respectively. Also, the widths w3 of the partial wirings in 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 be larger in order from the width w3a of the flexible circuit board 31a that is the innermost in the board stack 30 toward the outer periphery. That is, the widths are set to be 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 a 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 multiple flexible circuit boards 31 constituting the board 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 wirings 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, modified examples of the flexible circuit board 31 constituting the substrate laminate 30 according to the second embodiment will be described. [2.3.1 First modified example] Fig. 13 is a diagram showing a 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 board laminate 30 in place of the flexible circuit board 31. Note that reference numerals relating to wiring such as the first partial wiring U1a are omitted in Fig. 13.

[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 extending 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, to a range on the long side 33a or 33b 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 projections Tb, and can be dissipated more effectively through the case 42 of the motor 40.

[0114] [2.3.2 Second Modification] Fig. 14 is a diagram showing a 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 board laminate 30 in place of the flexible circuit board 31. Note that reference numerals relating to wiring such as the first partial wiring U1a are omitted in Fig. 14.

[0115] The flexible circuit board 312 has a similar configuration to the flexible circuit board 31, but the protrusions Tb are not configured as part of the insulating sheet 32, and are configured from a material having a higher thermal conductivity than the insulating sheet 32. Specifically, the protrusions Tb are configured from a heat conductive plate 36 that is separate from the insulating sheet 32 ​​and is configured from a material having a high thermal conductivity (e.g., copper, aluminum, etc.). The heat conductive 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 projection Tb is made of a material with high thermal conductivity, so that heat generated in the vias h of the connection conductors Jc can be dissipated more effectively. [2.3.2 Third Modification] Fig. 15 is a diagram showing a 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 board laminate 30 in place of the flexible circuit board 31. Note that reference numerals relating to wiring such as the first partial wiring U1a are omitted in Fig. 15.

[0117] The flexible circuit board 313 has a similar configuration to the flexible circuit board 31, but is different 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.) having a higher thermal conductivity than the insulating sheet 32. The flexible circuit board 313 is also different from the flexible circuit board 31 in that the protrusions Tb are not configured as part of the insulating sheet 32, but are parts of the outer edge plate 37 extending from the outer edge plate 37. The outer edge plate 37 extends, for example, in the long side 33a or 33b, in a range where the connection conductor portion Jc is 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 connection conductor portion Jc can be dissipated even more effectively.

[0119] [3. Other embodiments] In the flexible circuit board 10 shown in the first embodiment described above, the continuous wiring Uc, Vc, and Wc of the U-phase, V-phase, and W-phase respectively 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 shape and may be any shape. From the viewpoint of obtaining the largest possible generated magnetic force in the coil formed by the annular portion CR, it is desirable for the shape of the annular portion CR to have a large area of ​​the region that the annular portion CR includes.

[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 shape of partial wirings such as the first partial wiring U1 formed on each of the first main surface and the second main surface of the insulating sheet 11 into a broken line or a curved line. 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 include a protrusion 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 be configured similarly to the case 42 shown in Fig. 11, and allows the position of the flexible circuit board 10 inside the case 23 to be determined by the protrusion Tb, and allows the heat generated from the vias h of the connection conductors Jc to be efficiently dissipated.

[0122] In the above-described first and second embodiments, as an example, the flexible circuit board 10 and the substrate laminate 30 are used in the motors 20 and 40, which are three-layer brushless motors. However, the motors 20 and 40 are merely examples, and the flexible circuit board 10 and the substrate laminate 30 may be used in a generator having a similar configuration to the motors 20 and 40.

[0123] Moreover, 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 phase, V phase, and W phase, respectively, flow. However, the number of continuous wirings is not limited to three. Depending on the number of operating phases of a rotating electric machine to which the flexible circuit board 10 or the board laminate 30 is applied, the flexible circuit boards 10 and 31 may have continuous wirings of a number other than three.

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

[0125] (Configuration 1) A substrate laminate constructed by stacking a plurality of band-shaped flexible circuit boards bent into a cylindrical shape in the radial direction of the cylinder, each of the plurality of flexible circuit boards including a band-shaped insulating sheet and a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet, each of the plurality of flexible circuit boards having at least one protrusion disposed on at least one of two long sides extending in the longitudinal direction of the band-shaped insulating sheet and protruding from the long side toward the outside of the insulating sheet, each of the protrusions of the flexible circuit boards being positioned such that corresponding partial wirings among the plurality of flexible circuit boards overlap when the plurality of flexible circuit boards are stacked such that the positions of corresponding protrusions of the flexible circuit boards coincide with each other. According to the substrate laminate of configuration 1, the corresponding partial wirings of the multiple flexible circuit boards constituting the substrate laminate can be easily and accurately overlapped with each other. Therefore, for example, when a coil is formed on a flexible circuit board, the overlapping precision of the corresponding coils of the multiple flexible circuit boards can be improved to increase the strength of the magnetic field generated by the coil as a whole, which can contribute to the realization of a rotating electric machine with high energy efficiency.

[0126] (Configuration 2) The substrate laminate according to configuration 1, wherein the protruding portion of the flexible circuit board is provided with a heat transfer pattern made of a material having a higher thermal conductivity than the insulating sheet. According to the substrate laminate of configuration 2, heat generated in the flexible circuit board is quickly conducted from the protrusions having the heat conduction pattern to a structure such as a housing that houses the substrate laminate. As a result, when the substrate laminate of configuration 2 is used in a rotating electric machine, it is possible to suppress the temperature rise of magnetic bodies such as a stator and suppress the decrease in magnetic susceptibility, which can contribute to the realization of a rotating electric machine with high energy efficiency.

[0127] (Configuration 3) The substrate laminate according to configuration 2, wherein the heat transfer pattern is formed extending from the protrusion to a long side of the insulating sheet. According to the substrate laminate of configuration 3, heat generated in the flexible circuit board can be more quickly conducted from a wide area of ​​the protrusions and long sides of the insulating sheet having a heat conduction pattern to a structure such as a housing that houses the substrate laminate, thereby enabling more efficient heat dissipation.

[0128] (Configuration 4) The substrate laminate according to configuration 1, wherein the protrusion of the flexible circuit board is made of a material having a higher thermal conductivity than the insulating sheet. According to the substrate laminate of configuration 4, the entire protrusion is made of a material with high thermal conductivity, so that heat generated in the flexible circuit board can be dissipated more efficiently.

[0129] (Structure 5) The substrate laminate described in Structure 4, wherein the flexible circuit board has an edge plate arranged along the long side of the insulating sheet and made of a material having a higher thermal conductivity than the insulating sheet, and the protrusion portion is a portion of the edge plate extending from the edge plate. According to the substrate laminate of configuration 5, the outer edge plate made of a material with high thermal conductivity including a protrusion portion can be arranged over a wide area of ​​the long side of the insulating sheet, so that heat generated in the flexible circuit board can be dissipated even more efficiently.

[0130] (Configuration 6) The substrate laminate according to any one of configurations 1 to 5, wherein the protrusions of the flexible circuit board are disposed on both of the two long sides of the insulating sheet. According to the substrate laminate of Configuration 6, heat generated in the flexible circuit board can be dissipated more efficiently from the protrusions disposed on both of the two long sides.

[0131] (Structure 7) A substrate laminate according to any one of structures 1 to 6, wherein each of the multiple flexible circuit boards includes at least one continuous wiring formed on the insulating sheet, and the continuous wiring includes 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 the multiple partial wirings formed on each of the two opposing main surfaces of the insulating sheet through vias. According to the substrate laminate of configuration 7, corresponding continuous wirings having a long length extending in the longitudinal direction of the insulating sheet can be easily and accurately overlapped between the multiple flexible circuit boards constituting the substrate laminate. Therefore, for example, when a coil is formed on a flexible circuit board, the overlapping precision of corresponding coils between the multiple flexible circuit boards can be improved to increase the strength of the magnetic field generated by the coil as a whole, which can contribute to the realization of a rotating electric machine with high energy efficiency.

[0132] (Configuration 8) The substrate laminate described in Configuration 7, wherein in each of the multiple flexible circuit boards, the first continuous portion and the second continuous portion intersect in a chain-like manner without being conductive to each other in a projected plan view seen from the direction normal to the main surface of the insulating sheet, to form multiple annular portions connected in a chain-like manner, and each of the annular portions forms a coil. According to the substrate laminate of configuration 8, the annular portions that can form coils can be easily and accurately overlapped between the multiple flexible circuit boards that make up the substrate laminate, which can increase the overall strength of the magnetic field generated by the laminated coil that can be formed by the overlapped annular portions, thereby contributing to the realization of a rotating electric machine with high energy efficiency.

[0133] (Configuration 9) The substrate laminate according to configuration 7 or 8, wherein each of the plurality of flexible circuit boards includes 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 9, a highly energy-efficient multi-phase AC rotating electric machine can be realized.

[0134] (Configuration 10) A rotating electric machine having a stator including the substrate laminate according to configuration 9, and a rotor disposed inside a cylinder formed by the substrate laminate. According to the rotating electric machine of configuration 10, it is possible to provide a rotating electric machine that is lightweight and has improved energy efficiency.

[0135] (Structure 11) A flexible circuit board constituting the substrate laminate described in any one of Structures 1 to 9, comprising a band-shaped insulating sheet, a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet, and at least one protrusion disposed on at least one of two long sides extending in the longitudinal direction of the band-shaped insulating sheet, protruding from the long side toward the outside of the insulating sheet. According to the flexible circuit board of configuration 11, a substrate laminate can be formed that can contribute to the realization of a rotating electric machine with high energy efficiency. [Explanation of symbols]

[0136] 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, Tb...protrusion, U1, U1a, U1b, U1c, U1d, U1e, U1f, U1g, U1h, U1i, U1j, U1k, U1m...First partial wiring of U phase, V1, V1a, V1b, V1c, V1d, V1e, V1f, V1g, V1h, V1i, V1j, V1k, V1m...First partial wiring of V phase, W1, W1a, W1b, W1c, W1d, W1e, W1f, W1g, W1h, W1i, W1j, W1k, W1m...First partial wiring of W phase, U2, U2a, U2b, U2c, U2d, U2e, U2f, U2g, U2h, U2i, U2j, U2k, U2m...Second partial wiring of U phase, 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, U2...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 part wiring, Us11, Us12... U-phase double first continuous part of continuous wiring, Us21, Us22... U-phase double second continuous part of continuous wiring, Ut1, Ut2... U-phase double inversion part.

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 a plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet, 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 strip-shaped insulating sheet and protruding from the long side toward an outside of the insulating sheet, the projections of the flexible circuit boards are provided at positions such that the corresponding partial wirings overlap each other between the flexible circuit boards when the flexible circuit boards are stacked such that the positions of the corresponding projections of the flexible circuit boards coincide with each other; Substrate stack.

2. a heat transfer pattern formed of a material having a higher thermal conductivity than the insulating sheet is provided on the protruding portion of the flexible circuit board; The substrate laminate of claim 1 .

3. The heat transfer pattern is formed to extend from the protrusion to a long side of the insulating sheet. The substrate laminate according to claim 2 .

4. The protrusion of the flexible circuit board is made of a material having a higher thermal conductivity than the insulating sheet. The substrate laminate of claim 1 .

5. the flexible circuit board has an outer edge plate arranged along the long side of the insulating sheet and made of a material having a higher thermal conductivity than the insulating sheet; The protrusion is a portion of the outer edge plate that extends from the outer edge plate. The substrate laminate according to claim 4 .

6. The protrusions of the flexible circuit board are disposed on both of the two long sides of the insulating sheet. The substrate laminate of claim 1 .

7. Each of the flexible circuit boards includes at least one continuous wiring formed on the insulating sheet, The continuous wiring is the first continuous portion and the second continuous portion extending in the longitudinal direction of the insulating sheet are formed by alternately connecting the partial wirings formed on each of the two opposing main surfaces of the insulating sheet in cascade connection through vias; The substrate laminate of claim 1 .

8. In each of the plurality of flexible circuit boards, the first continuous portion and the second continuous portion intersect in a chain shape without being electrically connected to each other in a projected plan view seen from a direction normal to a main surface of the insulating sheet, to form a plurality of annular portions connected in a chain shape, and each of the annular portions forms a coil. The substrate laminate according to claim 7 .

9. 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 7 .

10. A stator comprising the substrate laminate according to claim 9; a rotor disposed inside a cylinder formed by the substrate laminate; A rotating electric motor having

11. A flexible circuit board constituting the substrate laminate according to any one of claims 1 to 9, A strip-shaped insulating sheet; A plurality of partial wirings formed on each of two opposing main surfaces of the insulating sheet; the insulating sheet has at least one protrusion disposed on at least one of two long sides extending in the longitudinal direction of the strip-shaped insulating sheet and protruding from the long side toward the outside of the insulating sheet; Flexible circuit board.

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