Motor stator and motor

Abstract

This motor stator (40) comprises a coil part (20) in which a plurality of coil units (21) are disposed in an annular shape, and a multilayer printed wiring board (10) that phase-connects the plurality of coil units (21) for power supply connection. The multilayer printed wiring board (10) includes: an annular crossover wire substrate (11) on which a first wiring pattern for phase-connecting winding terminals (23) of respective coils of the plurality of coil units (21) is formed; and a flexible substrate (12) on which a second wiring pattern for connecting the first wiring pattern of the crossover wire substrate (11) and power supply terminals of a plurality of phases is formed. At least the flexible substrate (12) among the crossover wire substrate (11) and the flexible substrate (12) is a bendable flexible substrate, the crossover wire substrate (11) and the flexible substrate (12) are integrated, and the surface of the flexible substrate (12) is subjected to insulation protective coating.

Description

Motor stator and motor

[0001] The present disclosure relates to a motor stator and a motor.

[0002] To achieve higher performance and functionality in industrial equipment such as mounters, robots, and NC (Numerical Control) processing machines, the servo motors that drive these devices are required to be faster, more precise, digitalized, and more compact. In the manufacturing process for servo motor stators, it is necessary to connect the terminals of the multiple phase coils arranged in a circular ring shape with crossover wires.

[0003] In Patent Document 1, multiple core pieces for three phases of UVW coils are arranged in a ring shape, and a multilayer printed wiring board consisting of a ring portion and a square portion protruding from the ring portion is provided on the multiple core pieces arranged in a ring shape, and the crossover wires between the coil terminals are connected using the multilayer printed wiring board. Using a multilayer printed wiring board to connect the crossover wires reduces the axial space compared to connecting with normal conductors, making it possible to reduce the size. Furthermore, since the wiring pattern specifying which terminals are connected to which terminals can be pre-formed on the multilayer printed wiring board, there are advantages such as eliminating incorrect wiring due to work errors, simplifying the wiring work, and reducing costs.

[0004] International Publication No. 2007 / 052385

[0005] However, in Patent Document 1, the UVW phase connection terminals that supply power to the multilayer printed wiring board from outside the motor are rectangular and protrude outward from the annular portion, making it difficult to reduce the diameter. Also, lead wires had to be connected to the UVW phase connection terminals of the multilayer printed wiring board by soldering or other methods. Furthermore, to ensure voltage resistance, the UVW phase connection terminals required insulating gaps between the phases and between the phases and ground, which was an obstacle to reducing the size of the motor.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a motor stator that does not require lead wire connections, does not require gaps for insulation, and can be made smaller.

[0007] In order to solve the above-mentioned problems and achieve the object, a motor stator of the present disclosure includes a coil section in which a plurality of coil units, each formed by winding a conductor around an iron core made of laminated electromagnetic steel sheets, are arranged in an annular shape, and a multilayer printed wiring board having multiple layers of printed wiring boards for connecting the plurality of coil units to a power source through phase connections. The multilayer printed wiring board includes: an annular first printed wiring board on which a first wiring pattern is formed for connecting each coil terminal of the plurality of coil units to connect the phases, and a second printed wiring board on which a second wiring pattern is formed for connecting the first wiring pattern of the first printed wiring board to power supply terminals for multiple phases, wherein at least the second printed wiring board of the first and second printed wiring boards is a bendable flexible board, the first printed wiring board and the second printed wiring board are integrated, and the surface of the second printed wiring board is coated with an insulating protective coating.

[0008] The motor stator of the present disclosure has the advantage that it is possible to achieve miniaturization because it does not require connection of lead wires and does not require gaps for insulation.

[0009] a perspective view showing the configuration inside a mold of the motor stator according to the first embodiment; a partially sectional side view showing a side configuration of the motor stator according to the first embodiment; a top view showing a multilayer printed wiring board constituting the motor stator according to the first embodiment; a cross-sectional view showing a multilayer printed wiring board constituting the motor stator according to the first embodiment; a flowchart for explaining a method for manufacturing the motor stator according to the first embodiment; a cross-sectional perspective view showing the configuration of a servo motor including the motor stator according to the first embodiment; a top view showing another example of the multilayer printed wiring board of the motor stator according to the first embodiment; a top view showing a multilayer printed wiring board constituting the motor stator according to the second embodiment; and a cross-sectional view showing a multilayer printed wiring board constituting the motor stator according to the second embodiment.

[0010] A motor stator and a motor according to an embodiment will be described below with reference to the drawings.

[0011] First Embodiment Fig. 1 is a perspective view showing the configuration inside a mold of a motor stator 40 according to a first embodiment. Fig. 2 is a partially cross-sectional side view showing the side configuration of the motor stator 40 according to the first embodiment. Fig. 3 is a top view showing a multilayer printed wiring board 10 that constitutes the motor stator 40 according to the first embodiment. Fig. 4 is a cross-sectional view of the multilayer printed wiring board 10 that constitutes the motor stator 40 according to the first embodiment. Fig. 4 is a cross-sectional view taken along line A-A in Fig. 3. As shown in Figs. 1 and 2, the motor stator 40 includes a coil section 20 and the multilayer printed wiring board 10.

[0012] The coil section 20 has a plurality of coil units 21 each having a conductor wound around an iron core 22 made of laminated electromagnetic steel sheets. The plurality of coil units 21 are arranged in a circular ring shape to form the coil section 20. The plurality of coil units 21 included in the coil section 20 form coil units for a plurality of phases, for example, UVW phases.

[0013] A crossover board 11 serving as a first printed wiring board of a multilayer printed wiring board 10 is disposed on an end face of the annular coil portion 20 on the side of the winding terminal 23. As shown in FIGS. 1, 3, and 4, the multilayer printed wiring board 10 includes the crossover board 11, a flexible board 12 serving as a second printed wiring board, and a power supply connector board 13 serving as a third printed wiring board. Of the crossover board 11, the flexible board 12, and the power supply connector board 13, at least the crossover board 11 is formed of a multilayer printed wiring board. In FIG. 4, the crossover board 11, the flexible board 12, and the power supply connector board 13 are formed of a multilayer printed wiring board including an insulating film 15 serving as an insulator and a wiring pattern 16 serving as a conductor layer. The wiring pattern 16 is, for example, copper foil.

[0014] The jumper wire board 11 has an annular shape and is provided with a plurality of through holes 14 arranged at equal intervals around the circumference, which are solder-connected to the winding terminals 23 of the plurality of coil units 21. The jumper wire board 11 is provided with a first wiring pattern 16a, which is a connection pattern for star-connecting or delta-connecting the UVW phases made up of the plurality of coil units 21.

[0015] The flexible substrate 12 is bendable, and is formed with a first wiring pattern 16a of the jumper substrate 11 and a second wiring pattern 16b for connecting the UVW phase power supply terminals. Furthermore, the surface of the flexible substrate 12 is covered with an insulating protective coating 17. In Fig. 3, the insulating protective coating 17 is applied to the hatched portions of the flexible substrate 12. In Figs. 1 and 2, the flexible substrate 12 is bent perpendicular to the substrate surface of the jumper substrate 11 and rises in a direction along the central axis of the coil section 20. In Fig. 3, the flexible substrate 12 is provided so as to extend radially inward of the annular jumper substrate 11.

[0016] The power feed connector board 13 is formed with a third wiring pattern 16c that is connected to the second wiring pattern 16b of the flexible board 12. Furthermore, the power feed connector board 13 is provided with through holes 14 that serve as power feed terminals for the UV and W phases that are connected to the third wiring pattern 16c. A power feed connector 30 is soldered to the through holes 14. In Figures 1 and 3, the power feed connector board 13 extends in the same direction as the flexible board 12. In Figure 2, the power feed connector board 13 is bent perpendicular to the flexible board 12.

[0017] Here, the jumper board 11 and the power feed connector board 13 are ordinary glass epoxy boards, and the flexible board 12 is integrated with the jumper board 11 and the power feed connector board 13. In other words, the multilayer printed wiring board 10 composed of the jumper board 11, the flexible board 12, and the power feed connector board 13 is a rigid-flexible board.

[0018] The flexible substrate 12 functions as a lead wire. In other words, in the first embodiment, the flexible substrate 12 is used instead of the lead wires that supply power from the outside of the motor (not shown) to the UVW phase connection terminals on the annular jumper substrate 11, and a rigid-flexible substrate is used as the multilayer printed wiring board 10, so that the process of connecting the lead wires to the jumper substrate 11 by soldering or the like is not required.

[0019] Furthermore, in conventional multilayer printed wiring board structures, the UVW phase connection terminals must be exposed to connect the lead wires to the multilayer printed wiring board, and to ensure voltage resistance, the connection terminals must have insulating gaps (3 mm clearance, 2.8 mm creepage distance) between the phases and between the connection terminals and ground. In contrast, according to embodiment 1, the annular crossover board 11 and flexible board 12 are integrated, and by covering the surface with a protective insulating coating 17, there are no exposed portions of the electrodes, including the connection terminals, and voltage resistance is improved. Therefore, since insulating gaps are no longer necessary, miniaturization is possible.

[0020] Here, the design specifications for the flexible substrate 12 and the jumper substrate 11 can be the same as those for a general multilayer printed wiring board without any problems. That is, the wiring conductor width and conductor spacing are each 0.18 mm or more, and the copper foil thickness is 35 μm or more. In practice, the design specifications for the flexible substrate 12 and the jumper substrate 11 are determined based on the motor's maximum current, duty, and required withstand voltage. For example, a general industrial motor is classified as transient overvoltage category III, so the short-term overvoltage (surge / impulse voltage) required for equipment with a system voltage of 300 V or less is 4000 Vpk.

[0021] Common coating materials for the multilayer printed wiring board 10 include polyolefin resin, silicone resin, and fluororesin. While these resins are easy to use because they dry naturally within a few minutes after application, they are thermoplastic and many have a heat resistance temperature of 100 to 150°C, so it is necessary to select a resin that can withstand the molding process described below. Furthermore, the breakdown voltage of these resins is said to be 80 to 100 V / μm, so a film thickness of approximately 50 μm is required.

[0022] In contrast, polyamide-imide resin requires a drying process (210°C / 1 hour) after application, but has a high glass transition temperature of 220°C and is therefore able to withstand the molding process. Furthermore, its high dielectric breakdown voltage of 250-400 V / μm makes it an ideal material for the insulating protective coating 17. Even if the dielectric breakdown voltage is the minimum of 250 V / μm, there is no problem as long as the film thickness is 16 μm or more, which is about one-third the film thickness of other resins.

[0023] Next, a method for manufacturing motor stator 40 will be described. Fig. 5 is a flowchart for explaining a method for manufacturing motor stator 40 according to the first embodiment. First, coil unit 21 is manufactured by winding a conductor around iron core 22 formed by laminating electromagnetic steel sheets. Next, multiple coil units 21 are arranged in an annular shape and fixed by welding to form coil portion 20 (step S100).

[0024] Next, the winding terminals 23 of the multiple coil units 21 of the coil section 20 are soldered through multiple through holes 14 in the annular jumper board 11 of the multilayer printed wiring board 10, thereby connecting the coil section 20 and the jumper board 11 (step S110).

[0025] A connection pattern for star-connecting or delta-connecting the UVW phases is prepared in advance on the crossover board 11, and a wiring pattern for connecting the winding terminal 23 of which coil unit 21 to the winding terminal 23 of which coil unit 21 is also prepared in advance, so that there is no erroneous wiring due to work mistakes, the wiring work is simplified, and costs are reduced.

[0026] Next, flexible substrate 12 and power supply connector substrate 13 of multilayer printed wiring board 10 are bent at a right angle from jumper wire substrate 11 and drawn out in the axial direction of coil portion 20. Then, in this state, multilayer printed wiring board 10 and coil portion 20 are molded with epoxy resin to complete motor stator 40 (step S120).

[0027] Finally, the power feed connector 30 is soldered to the through-hole 14 of the power feed connector board 13 to connect the power feed connector 30 to the power feed connector board 13 (step S130).

[0028] Fig. 6 is a cross-sectional perspective view showing the configuration of a servo motor 100 including a motor stator 40 according to the first embodiment. In addition to the motor stator 40 having the coil section 20 and the multilayer printed wiring board 10, the servo motor 100 also includes a power supply connector 30, a rotor 50, a brake 60, an encoder 70, a bracket 80, and an encoder cover 90. After manufacturing the motor stator 40 according to the procedure shown in Fig. 5, the rotor 50, the brake 60, the bracket 80, the encoder 70, and the encoder cover 90 are successively assembled to produce the servo motor 100.

[0029] As described above, according to the first embodiment, flexible board 12 is used instead of the lead wires that supply power from the outside of the motor to the UVW phase connection terminals on annular jumper board 11, and flexible board 12 and jumper board 11 are directly connected and integrated, so that the process of connecting lead wires by soldering or the like is not required.

[0030] Furthermore, according to embodiment 1, the power supply connector 30 is directly soldered to the through-hole 14 of the power supply connector board 13, which has the advantage of eliminating the possibility of incorrect wiring due to operational mistakes, simplifying the wiring work, and reducing costs, compared to the conventional method of soldering the lead wires one by one.

[0031] Furthermore, according to embodiment 1, the annular jumper wire substrate 11 and the flexible substrate 12 are integrated and their surfaces are covered with an insulating protective coating 17, which increases the pressure resistance and eliminates the need to ensure gaps for the insulation distance between the lead wires and the bracket 80 and encoder cover 90, which was previously necessary, making it possible to reduce the size.

[0032] Furthermore, according to embodiment 1, a bendable flexible substrate 12 is used and is pulled out perpendicularly from the jumper wire substrate 11 in the axial direction of the motor, so that the flexible substrate 12 does not protrude outside the coil section 20, making it possible to reduce the size.

[0033] Fig. 7 is a top view showing another example of the multilayer printed wiring board 10 of the motor stator 40 according to the first embodiment. In a small-diameter motor, as shown in Fig. 7, the flexible board 12 may be disposed on the outside of the jumper board 11. In Fig. 7, the hatched portion of the flexible board 12 is coated with an insulating protective coating 17.

[0034] Second Embodiment. Figure 8 is a top view of a multilayer printed wiring board 10 constituting a motor stator 40 according to a second embodiment. Figure 9 is a cross-sectional view of a multilayer printed wiring board 10 constituting a motor stator 40 according to the second embodiment. Figure 9 is a cross-sectional view taken along the line A-A in Figure 8. In the first embodiment, the surface of the flexible substrate 12 is covered with a protective coating 17. However, in the second embodiment, not only the surface of the flexible substrate 12 but also a portion of the jumper substrate 11 and a portion of the power feed connector substrate 13 connected to the flexible substrate 12 are covered with the protective coating 17. That is, the protective coating 17 is also applied to a portion of the surface of the jumper substrate 11 facing the flexible substrate 12 and a portion of the surface of the power feed connector substrate 13 facing the flexible substrate 12. The remaining structure and assembly method of the second embodiment are the same as those of the first embodiment, and therefore a redundant description will be omitted.

[0035] According to the second embodiment, in addition to the effects of the first embodiment, even when the flexible substrate 12 is bent immediately near the connection point of the jumper substrate 11 or the power supply connector substrate 13, the wiring pattern 16 can be prevented from being exposed, which further improves the pressure resistance and makes it possible to reduce the size because there is no need to secure a gap for insulation.

[0036] The flexible substrate 12 and the entire surfaces of the crossover substrate 11 and the power supply connector substrate 13 except for the through holes 14 may be covered with an insulating protective coating 17 .

[0037] Embodiment 3. In the first embodiment, multilayer printed wiring board 10 is described as a rigid-flexible board, but in the third embodiment, in addition to flexible board 12, jumper board 11 and power feed connector board 13 are also flexible boards, and all boards in multilayer printed wiring board 10 are bendable flexible boards. In other words, of jumper board 11, flexible board 12, and power feed connector board 13, at least jumper board 11 may be a bendable flexible board.

[0038] Embodiment 4 In embodiment 4, the power feed connector board 13 is eliminated, and UVW phase power feed terminals are provided at the end of the flexible board 12 so that the flexible board 12 can be directly inserted into the power feed connector 30 to connect the power feed. This eliminates the need for soldering between the power feed connector board 13 and the power feed connector 30, which was necessary in embodiment 1, and is expected to further simplify the work.

[0039] The configurations shown in the above embodiments are examples of the contents of the present disclosure, and can be combined with other known technologies, or the configurations of each embodiment can be combined. Parts of the configurations can also be omitted or modified within the scope of the gist of the present disclosure.

[0040] REFERENCE SIGNS LIST 10 multilayer printed wiring board, 11 jumper wire board, 12 flexible board, 13 power supply connector board, 14 through hole, 15 insulating film, 16 wiring pattern, 16a first wiring pattern, 16b second wiring pattern, 16c third wiring pattern, 17 insulating protective coating, 20 coil portion, 21 coil unit, 22 iron core, 23 winding terminal, 30 power supply connector, 40 motor stator, 50 rotor, 60 brake, 70 encoder, 80 bracket, 90 encoder cover, 100 servo motor.

Claims

1. A motor stator comprising: a coil section in which a plurality of coil units, each formed by winding a conductor around an iron core made of laminated electromagnetic steel sheets, are arranged in an annular shape; and a multilayer printed wiring board having multiple layers of printed wiring boards that connect the plurality of coil units together in phase and connect them to a power source, wherein the multilayer printed wiring board comprises: a first annular printed wiring board on which a first wiring pattern is formed that connects each coil terminal of the plurality of coil units to connect the phases; and a second printed wiring board on which a second wiring pattern is formed that connects the first wiring pattern of the first printed wiring board to power supply terminals for multiple phases, wherein at least the second printed wiring board of the first and second printed wiring boards is a bendable flexible board, the first printed wiring board and the second printed wiring board are integrated, and the surface of the second printed wiring board is coated with an insulating protective coating.

2. The motor stator according to claim 1, wherein the multilayer printed wiring board further comprises a third printed wiring board on which are formed multi-phase power supply terminals to which multi-phase power supply connectors are connected, the second wiring pattern of the second printed wiring board connects the first wiring pattern of the first printed wiring board to the multi-phase power supply terminals of the third printed wiring board, at least the second printed wiring board of the first, second and third printed wiring boards is a bendable flexible board, and the first, second and third printed wiring boards are integrated.

3. A motor stator as described in claim 1 or 2, characterized in that the first printed wiring board is placed on the end face of the coil section arranged in a circular ring shape, and the second printed wiring board is bent relative to the first printed wiring board and stands up in a direction along the central axis of the coil section.

4. The motor stator according to claim 2, wherein the insulating protective coating is applied to a portion of the surface of the first printed wiring board facing the second printed wiring board and a portion of the surface of the third printed wiring board facing the second printed wiring board.

5. A motor comprising: a motor stator according to any one of claims 1 to 4; and a rotor assembled to the motor stator.

6. The motor according to claim 5, further comprising: a brake assembled to the rotor; and an encoder assembled to the brake.

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