JP4971642B2 - Brushless motor - Google Patents

Description

  The present invention provides a resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, a control means for controlling power supply to the motor stator based on a detection signal of the resolver, The present invention relates to a brushless motor including an exciting coil of a resolver, a first output coil and a second output coil, and a multicore cable that electrically connects a control means.

  Conventionally, an inner rotor type or an outer rotor type is known as a brushless motor in which a rotor is rotated with respect to a stator that forms a magnetic field. In an inner rotor type brushless motor, a rotor having a multipolar magnet is disposed inside a cylindrical stator in which a plurality of teeth protrudes inward, and the rotor is rotated by a magnetic field of the stator. . In an outer rotor type brushless motor, a cylindrical rotor having a multipolar magnet is disposed outside a stator in which a plurality of teeth protrude radially outwardly, and the rotor is rotated by a magnetic field of the stator. .

  The magnetic field is formed by switching the energization state of the coils wound around the teeth of the stator based on the rotation angle of the rotor with respect to the stator. The rotation angle of the rotor is detected by a sensor or an encoder. A resolver is known as a sensor for detecting the rotation angle of the rotor. In the resolver, an excitation winding and a two-phase output winding are wound around a stator core having a plurality of teeth disposed around the rotor. A SIN output and a COS output are obtained from the two-phase output winding. A part of the rotor is formed such that the gap permeance changes sinusoidally with respect to the angle θ. When the rotor is rotated, an excitation voltage is output as a COS output voltage and a SIN output voltage, and the rotation angle of the rotor is obtained based on these outputs (for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-253140 (FIG. 3)

  The brushless motor is provided with a control means separately from a motor main body made of a stator, a rotor, or the like. The control means obtains the rotation angle of the rotor based on the output signal from the resolver, and controls the current supplied to the stator. The resolver of the motor body and the control means are electrically connected by a multicore cable. A multi-core cable is a cable in which a plurality of core wires are arranged in a predetermined circumferential arrangement, and for example, a 4-core cable or a 6-core cable is used.

  Depending on the use of the brushless motor, the arrangement of the brushless motor and the control means is determined, and the length of the multicore cable is also determined. Due to the recent versatility of brushless motors, for example, multi-core cables having a length of 1 meter or more may be used.

  An electrical error inherent to the resolver occurs in the rotation angle of the rotor detected by the resolver. In order to drive the brushless motor smoothly, it is preferable that such an electrical error is small.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a brushless motor capable of reducing an electrical error of a rotation angle detected by a resolver.

  The inventor of the present invention pays attention to the fact that the electrical error of the rotation angle detected by the resolver is increased by the connection of the multicore cable, and the impedance imbalance of each core wire of the multicore cable adversely affects the electrical error. As a result, the present invention has been completed.

(1) A brushless motor according to the present invention includes a resolver that detects a rotation angle of a motor rotor that is rotated by a magnetic field formed by the motor stator, and supplies power to the motor stator based on a detection signal of the resolver. Control means for controlling, and a multi-core cable that electrically connects the exciting coil of the resolver, the first output coil and the second output coil, and the control means, and the multi-core cable has a cross-sectional structure. The first lead wire, the second lead wire, the third lead wire, the fourth lead wire, the fifth lead wire, and the sixth lead wire are arranged in a circumferential direction in the clockwise direction in FIG. The first output coil is connected to the third lead wire and the fourth lead wire, and the second output coil is connected to the fifth lead wire and the second lead wire. Connect to 6th lead It has been done .

The control means obtains the rotation angle of the motor rotor based on the output signal of the resolver, and supplies a current suitable for the rotation angle to the motor stator. The resolver and the control means are electrically connected by a multicore cable. The output signal of the first output coil and the output signal of the second output coil of the resolver are transmitted to the control means through each lead wire of the multicore cable. The first output coil and the second output coil are respectively connected to lead wires at positions where the respective impedances are substantially equal. That is, the output signal of the first output coil and the output signal of the second output coil are transmitted through the lead wires at positions where the impedances are substantially equivalent. Thereby, since the change of the output voltage of the output signal of a 1st output coil and the output signal of a 2nd output coil is balanced, the electrical error of the resolver by the connection of a multicore cable does not arise.

  (2) A brushless motor according to the present invention includes a resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, and supplying power to the motor stator based on a detection signal of the resolver. Control means for controlling, and a multi-core cable that electrically connects the exciting coil of the resolver, the first output coil and the second output coil, and the control means, and the multi-core cable has a cross-sectional structure. The first lead wire, the second lead wire, the third lead wire, the fourth lead wire, the fifth lead wire, and the sixth lead wire are arranged in a circumferential direction in the clockwise direction in FIG. The first output coil is connected to the third lead wire and the fifth lead wire, and the second output coil is connected to the fourth lead wire and the second lead wire. Connect to 6th lead wire It is those that have been.

  (3) A brushless motor according to the present invention includes a resolver that detects a rotation angle of a motor rotor that is rotated by a magnetic field formed by the motor stator, and supplies power to the motor stator based on a detection signal of the resolver. Control means for controlling, and a multi-core cable that electrically connects the exciting coil of the resolver, the first output coil and the second output coil, and the control means, and the multi-core cable has a cross-sectional structure. The first lead wire, the second lead wire, the third lead wire, the fourth lead wire, the fifth lead wire, and the sixth lead wire are arranged in a circumferential direction in the clockwise direction in FIG. The first output coil is connected to the second lead wire and the fifth lead wire, and the second output coil is connected to the first lead wire and the sixth lead wire. Connect to 6th lead wire It is those that have been.

  (4) A brushless motor according to the present invention includes a resolver that detects a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, and supplies power to the motor stator based on a detection signal of the resolver. Control means for controlling, and a multi-core cable that electrically connects the exciting coil of the resolver, the first output coil and the second output coil, and the control means, and the multi-core cable has a cross-sectional structure. 1, the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged in a circle in the clockwise direction, and the exciting coil includes the second lead wire and the fourth lead wire. The first output coil is connected to the first lead wire and the second lead wire, and the second output coil is connected to the second lead wire and the third lead wire. is there.

  (5) A brushless motor according to the present invention includes a resolver that detects a rotation angle of a motor rotor that is rotated by a magnetic field formed by the motor stator, and supplies power to the motor stator based on a detection signal of the resolver. Control means for controlling, and a multi-core cable that electrically connects the exciting coil of the resolver, the first output coil and the second output coil, and the control means, and the multi-core cable has a cross-sectional structure. In the clockwise direction, the first lead wire, the second lead wire, the third lead wire, the fourth lead wire, the fifth lead wire, the sixth lead wire, the seventh lead wire, the eighth lead wire, the ninth lead wire, The tenth lead wire is arranged in a circle, the excitation coil is connected to the fifth lead wire and the eighth lead wire, and the first output coil is connected to the fourth lead wire and the sixth lead wire. Connected to the lead wire The second output coil is connected to the seventh lead wire and the ninth lead wire, and the first lead wire, the second lead wire, the third lead wire, and the tenth lead wire are formed by a motor stator. It is used for supplying a current for a magnetic field.

According to the brushless motor according to the present invention, the output signal of the first output coil and the output signal of the second output coil of the resolver are respectively transmitted by the lead wires at positions where the impedance is substantially equivalent in the multicore cable. The change in the output voltage of the output signal of the first output coil and the output signal of the second output coil is balanced. As a result, the electrical error of the resolver due to the connection of the multicore cable does not deteriorate, and smooth driving of the brushless motor is realized.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only one aspect of the brushless motor according to the present invention. For example, the inner rotor type brushless motor is changed to an outer rotor type brushless motor, and the gist of the present invention is not changed. It goes without saying that the embodiment can be changed.

  FIG. 1 is a schematic diagram showing a configuration of a brushless motor 1 according to an embodiment of the present invention. The brushless motor 1 includes a motor body 2 and a control unit 3 electrically connected by a power cable 4 and a sensor cable 5.

  The motor body 2 is roughly divided into a motor unit 10 mainly composed of a stator 11 (corresponding to a motor stator) and a rotor 12 (corresponding to a motor rotor), and a resolver 13 that detects a rotation angle of the rotor. Are integrally provided in the housing 14.

  FIG. 2 shows a cross-sectional configuration of the motor unit 10. The brushless motor 1 is an inner rotor type in which a rotor 12 is rotated inside a cylindrical stator 11. A rotor 12 is disposed in a space inside the stator 11 with a predetermined magnetic gap therebetween, and the rotor 12 is rotatably supported by a casing 14. The rotor 12 is rotated by the magnetic field formed by the stator 11.

  The stator 11 has twelve divided cores 15. Twelve divided cores 15 are connected to form one cylindrical stator core. A motor coil 16 is wound around each divided core 15. The motor coil 16 is formed, for example, by winding a single copper wire around the plurality of divided cores 15 using a flyer type or nozzle type winding machine. A group of split cores, each of which is formed by winding one copper wire into a group, is formed for each phase of the U phase, V phase, and W phase, and the three split core groups are connected in an annular shape with a predetermined arrangement. Then, the 12-slot stator 11 is configured by being appropriately connected. U-phase, V-phase, and W-phase currents are supplied to the stator 11 through the power cable 4.

  The rotor 12 is provided on a shaft 17 serving as an axis of the brushless motor 1 such that a rotor yoke 18 is concentric with the shaft 17, and an 8-pole cylindrical magnet 19 is fixed to the outer periphery of the rotor yoke 18. The rotor yoke 18 is formed by laminating steel plates punched in a disc shape and integrating them by caulking or the like. A through hole is formed in the center of the rotor yoke 18 and the shaft 17 is inserted therethrough. The magnet 19 is a permanent magnet in which magnet particles are sintered in a cylindrical shape, and N poles and S poles are alternately formed in the circumferential direction to form eight poles.

  In this embodiment, the brushless motor 1 having 8 poles and 12 slots is described, but the number of poles and the number of slots of the motor are not particularly limited in the present invention. Further, it is arbitrary whether or not the stator core is composed of divided cores.

  FIG. 3 shows the configuration of the resolver 13. In the resolver 13, eight tooth portions 20 protrude in a circular shape toward the inside, and a sensor stator 22 in which a sensor coil 21 is wound around each tooth portion 20, and the center of the sensor stator 22. The sensor rotor 23 that is rotatably arranged is a main component.

  In the sensor stator 22, an exciting coil 38, a SIN output coil 39 (corresponding to a first output coil), and a COS output coil 40 (corresponding to a second output coil) are wound around the stator core 24 by a predetermined winding method. Being done. In FIG. 3, the excitation coil 38, the SIN output coil 39 and the COS output coil 40 are all shown as the sensor coil 21.

  The stator core 24 has a substantially annular outer shape as a whole, and has eight teeth portions 20 projecting radially inward from the inner peripheral surface thereof. The stator core 24 is formed, for example, by pressing a steel plate having a predetermined thickness into a plan view shape shown in FIG. 3, laminating a plurality of the steel plates and fixing them together by caulking or the like. An excitation coil 38, a SIN output coil 39, and a COS output coil 40 are wound around each of the eight teeth portions 20 of the stator core 24, and are wound by a predetermined winding method to form the sensor coil 21. The SIN output coil 39 and the COS output coil 40 are wound around each tooth portion 20 of the stator core 24 so that the phases thereof are different by 90 °. By applying a predetermined voltage to the exciting coil 38, a SIN output voltage (output signal) is obtained from the SIN output coil 39, and a COS output voltage (output signal) is obtained from the COS output coil 40. The voltage applied to the exciting coil 38, the SIN output voltage 39, and the COS output voltage 40 are transmitted between the resolver 13 and the control unit 3 through the sensor cable 5.

  The sensor rotor 23 has a substantially annular outer shape as a whole. The outer periphery of the sensor rotor 23 has a shape in which the gap permeance with the sensor stator 22 changes in a sine wave shape with respect to the angle θ in the rotation direction of the sensor rotor 23. The sensor rotor 23 is formed, for example, by pressing a steel plate having a predetermined thickness into a planar view shape of the sensor rotor 23 shown in FIG. 3, and laminating a plurality of the steel plates and fixing them together by caulking or the like. Is done. In the present embodiment, the sensor rotor 23 is a so-called shaft multiple angle 2X in which convex portions are formed at two locations on the outer shape, but other sensor rotors such as 1X, 3X, and 4X may be employed. Good. The sensor rotor 23 is fixed coaxially to the shaft 17 of the motor unit 10 and is rotated integrally with the shaft 17.

  The control unit 3 is a so-called motor driver that obtains the rotation angle of the rotor 12 based on the SIN output voltage and the COS output voltage output from the resolver 13 and applies a predetermined current to the three-phase motor coil 16. The motor body 2 and the control unit 3 are electrically connected by a power cable 4 and a sensor cable 5. A current applied to the motor coil 16 is transmitted by the power cable 4. The SIN output voltage and the COS output voltage output from the resolver 13 are transmitted by the sensor cable 5.

  FIG. 4 shows a cross-sectional configuration of the sensor cable 5. The sensor cable 5 is a multi-core cable composed of six lead wires 31 to 36 (corresponding to a core wire). The sensor cable 5 has an interposed shaft 30 disposed at the center. The intervening shaft 30 is a rope having the same length as the sensor cable 5 and is made of an insulating elastic member such as rubber. In the present embodiment, a multi-core cable having the interposed shaft 30 is shown, but the interposed shaft of the multi-core cable according to the present invention has an arbitrary configuration. Therefore, for example, a multi-core cable in which other lead wires are arranged around one lead wire may be used.

  The lead wires 31 to 36 are copper wires that are insulation-coated with a vinyl resin or the like. The six lead wires 31 to 36 are aligned around the interposed shaft 30 in a predetermined circumferential arrangement. Each of the six lead wires 31 to 36 can be identified by coloring the insulating coating material. In the present embodiment, the first lead wire 31, the second lead wire 32, the third lead wire 33, the fourth lead wire 34, the fifth lead wire 35, and the sixth lead wire 36 from the upper side in FIG. By being referred to, the six lead wires 31 to 36 are identified. Note that the first to sixth orders are for convenience, and it is arbitrary which one is used as the first lead wire and which is sequentially numbered in any direction. An exterior material 37 is provided outside the first to sixth lead wires 31 to 36 arranged in the circumferential direction. The exterior material 37 is a tube-shaped elastic member, and for example, a rubber tube is used. By covering the outer sides of the first to sixth lead wires 31 to 36 with the exterior member 37, the circumferential arrangement of the first to sixth lead wires 31 to 36 is maintained.

  The first to sixth lead wires 31 to 36 are connected to the sensor coil 21 of the resolver 13. As described above, the sensor coil 21 includes three types of the exciting coil 38, the SIN output coil 39, and the COS output coil 40. Each coil has two connection ends, and any two of the first to sixth lead wires 31 to 36 are connected to any one of the excitation coil 38, the SIN output coil 39, and the COS output coil 401.

  FIG. 5 is a schematic diagram showing each coil connected to the first to sixth lead wires 31 to 36. In FIG. 5, the exciting coil 38, the SIN output coil 39, and the COS output coil 40 are schematically shown outside the first to sixth lead wires 31 to 36. In FIG. 5, the exterior material 37 of the sensor cable 5 is omitted.

  The exciting coil 38 is connected to the first lead wire 31 and the second lead wire 32. The SIN output coil 39 is connected to the third lead wire 33 and the fourth lead wire 34. The COS output coil 40 is connected to the fifth lead wire 35 and the sixth lead wire 36. As shown in FIG. 5, the third lead wire 33 and the fourth lead wire 34 are adjacent to each other. Further, the fifth lead wire 35 and the sixth lead wire 36 are adjacent to each other. Therefore, the impedance between the third lead wire 33 and the fourth lead wire 34 and the impedance between the fifth lead wire 35 and the sixth lead wire 36 are theoretically the same. In other words, in the SIN output coil 39 and the COS output coil 40, the output signal is transmitted by the lead wire having the same impedance in the sensor cable 5. Therefore, the changes in the SIN output voltage and the COS output voltage when transmitted from the resolver 13 to the control unit 3 are approximately the same. In the present embodiment, the impedance between the first lead wire 31 and the second lead wire 32 to which the exciting coil 38 is connected is also the same as the above two impedances.

  In this way, the SIN output voltage of the SIN output coil 39 and the COS output voltage of the COS output coil 40 have the third lead wire 33, the fourth lead wire 34, the fifth lead wire 35, and the Since the resolver 13 and the control unit 3 are connected by the sensor cable 5 so as to be transmitted through the six lead wires 36, changes in the SIN output voltage and the COS output voltage are balanced. Thereby, the electrical error of the resolver 13 by the sensor cable 5 does not deteriorate, and the smooth drive of the brushless motor 1 is realized.

(First modification)
FIG. 6 is a diagram showing a first modification of the above embodiment. The first modification has the same configuration as that of the above embodiment except that the first to sixth lead wires 31 to 36 connected to the coils are different. In the first modification, the exciting coil 38 is connected to the first lead wire 31 and the second lead wire 32. The SIN output coil 39 is connected to the third lead wire 33 and the fifth lead wire 35. The COS output coil 40 is connected to the fourth lead wire 34 and the sixth lead wire 36. As shown in FIG. 6, the third lead wire 33 and the fifth lead wire 35 are separated by interposing one fourth lead wire 34. Further, the fourth lead wire 34 and the sixth lead wire 36 are separated with a single fifth lead wire 35 interposed therebetween. Therefore, the impedance between the third lead wire 33 and the fifth lead wire 35 and the impedance between the fourth lead wire 34 and the sixth lead wire 36 are theoretically the same. In other words, in the SIN output coil 39 and the COS output coil 40, the output signal is transmitted by the lead wire having the same impedance in the sensor cable 5. Therefore, the changes in the SIN output voltage and the COS output voltage when transmitted from the resolver 13 to the control unit 3 are approximately the same.

  Thus, even if the SIN output coil 39 and the COS output coil 40 are connected, the changes in the SIN output voltage and the COS output voltage are balanced. Thereby, the electrical error of the resolver 13 by the sensor cable 5 does not deteriorate, and the smooth drive of the brushless motor 1 is realized.

(Second modification)
FIG. 7 is a diagram illustrating a second modification of the embodiment. The second modification has the same configuration as that of the above embodiment except that the first to sixth lead wires 31 to 36 connected to the coils are different. In the second modification, the exciting coil 38 is connected to the third lead wire 33 and the sixth lead wire 36. The SIN output coil 39 is connected to the second lead wire 32 and the fifth lead wire 35. The COS output coil 40 is connected to the first lead wire 31 and the fourth lead wire 34. As shown in FIG. 7, the second lead wire 33 and the fifth lead wire 35 are separated by interposing two lead wires. In addition, the first lead wire 31 and the fourth lead wire 34 are separated by interposing two lead wires. Therefore, the impedance between the second lead wire 32 and the fifth lead wire 35 and the impedance between the first lead wire 31 and the fifth lead wire 35 are theoretically the same. In other words, in the SIN output coil 39 and the COS output coil 40, the output signal is transmitted through the lead wire having the same impedance in the sensor cable 5. Therefore, the changes in the SIN output voltage and the COS output voltage when transmitted from the resolver 13 to the control unit 3 are approximately the same. In the present embodiment, the impedance between the third lead wire 33 and the sixth lead wire 36 to which the exciting coil 38 is connected is also the same as the above two impedances.

  Thus, even if the SIN output coil 39 and the COS output coil 40 are connected, the changes in the SIN output voltage and the COS output voltage are balanced. Thereby, the electrical error of the resolver 13 by the sensor cable 5 does not deteriorate, and the smooth drive of the brushless motor 1 is realized.

(Third Modification)
FIG. 8 is a diagram illustrating a third modification of the embodiment. In the third modified example, a multi-core cable including four lead wires 41 to 44 is used as the sensor cable 6 to which the resolver 13 and the control unit 3 are connected. Such a cable is generally called a four-core cable. The sensor cable 6 has the same configuration as that of the sensor cable 5 except that the number of lead wires is different. An interposition shaft 45 is arranged at the center, and the first lead wire 41, the second lead wire 42, and the third lead are arranged around the shaft. The wire 43 and the fourth lead wire 44 are aligned in a predetermined circumferential arrangement. Although not shown in FIG. 8, a tube-shaped exterior material is provided outside the first to fourth lead wires 41 to 44 arranged in the circumferential direction, as in the above embodiment. The circumferential arrangement of the first to fourth lead wires 41 to 44 is maintained.

  In the third modification, the exciting coil 38 is connected to the second lead wire 42 and the fourth lead wire 44. The SIN output coil 39 is connected to the first lead wire 41 and the second lead wire 42. The COS output coil 40 is connected to the second lead wire 42 and the third lead wire 43. That is, the second lead wire 42 is shared as a ground line. As shown in FIG. 8, the first lead wire 41 and the second lead wire 42 are adjacent to each other. The second lead wire 42 and the third lead wire 43 are adjacent to each other. Therefore, the impedance between the first lead wire 41 and the second lead wire 42 and the impedance between the second lead wire 42 and the third lead wire 43 are theoretically the same. In other words, in the SIN output coil 39 and the COS output coil 40, the output signal is transmitted through the lead wire having the same impedance in the sensor cable 6. Therefore, the changes in the SIN output voltage and the COS output voltage when transmitted from the resolver 13 to the control unit 3 are approximately the same.

  Thus, even if the SIN output coil 39 and the COS output coil 40 are connected to the four-core sensor cable 6, changes in the SIN output voltage and the COS output voltage are balanced. Thereby, the electrical error of the resolver 13 by the sensor cable 5 does not deteriorate, and the smooth drive of the brushless motor 1 is realized.

(Fourth modification)
FIG. 9 is a diagram showing a fourth modification of the embodiment. In the fourth modified example, the connection between the resolver 13 and the control unit 3 and the connection between the motor unit 10 and the control unit 3 are made by a single cable 7. That is, the cable 7 not only transmits the output voltage from the resolver 13 but also includes a lead wire (conductive wire) for supplying a drive current to the stator 11 of the motor unit 10. Therefore, the power cable 4 shown in the above embodiment is not used.

  The cable 7 is a multi-core cable composed of ten lead wires 51 to 60. Such a cable is generally called a 10-core cable. The cable 7 has the same configuration as that of the sensor cable 5 except that the number of lead wires is different. The interposed shaft 50 is disposed at the center, and the first lead wire 51, the second lead wire 52, and the third lead wire are arranged around the shaft. 53, the fourth lead wire 54, the fifth lead wire 55, the sixth lead wire 56, the seventh lead wire 57, the eighth lead wire 58, the ninth lead wire 59, and the tenth lead wire 60 are arranged in a predetermined circumference. Are aligned. Although not shown in FIG. 9, a tube-shaped exterior material is provided outside the first to tenth lead wires 51 to 60 arranged in the circumferential direction, as in the above embodiment. The circumferential arrangement of the first to tenth lead wires 51 to 60 is maintained.

  In the fourth modification, the exciting coil 38 is connected to the fifth lead wire 55 and the eighth lead wire 58. The SIN output coil 39 is connected to the fourth lead wire 54 and the sixth lead wire 56. The COS output coil 40 is connected to the seventh lead wire 57 and the ninth lead wire 59. The first lead wire 51, the second lead wire 52, the third lead wire 53, and the tenth lead wire 60 are used for supplying drive current to the stator 11 of the motor unit 10. That is, these four lead wires 51, 52, 53, 60 are used as U-phase, V-phase, and W-phase power supply and ground wires.

  As shown in FIG. 9, the fourth lead wire 54 and the sixth lead wire 56 are separated by the interposition of one fifth lead wire 55. In addition, the seventh lead wire 57 and the ninth lead wire 59 are separated by a single eighth lead wire 58 interposed therebetween. Therefore, the impedance between the fourth lead wire 54 and the sixth lead wire 56 and the impedance between the seventh lead wire 57 and the ninth lead wire 59 are theoretically the same. In other words, in the SIN output coil 39 and the COS output coil 40, the output signal is transmitted by the lead wire having the same impedance in the cable 7. Therefore, the changes in the SIN output voltage and the COS output voltage when transmitted from the resolver 13 to the control unit 3 are approximately the same.

  As described above, even if the SIN output coil 39 and the COS output coil 40 are connected to the 10-core cable 7 including the lead wire for supplying power to the motor unit 10, the changes in the SIN output voltage and the COS output voltage are balanced. become. Thereby, the electrical error of the resolver 13 by the cable 7 does not deteriorate, and the smooth driving of the brushless motor 1 is realized.

  In this modification, one mode of connection of the SIN output coil 39 and the COS output coil 40 in the 10-core cable 7 is shown. The impedance of the lead wire to which the SIN output coil 39 is connected and the COS output coil are shown. It goes without saying that the connection arrangement may be changed as appropriate so that the impedance of the lead wire to which 40 is connected is equivalent.

Examples of the present invention are shown below. As shown in the first modified example (see FIG. 6),
As each coil is connected to the first lead wire 31 and the second lead wire 32, the third lead wire 33 and the fifth lead wire 35, the fourth lead wire 34 and the sixth lead wire 36, each of the sensor cables 5 The impedance between the lead wires was measured using three cables of the same kind. The results are shown in Table 1.

  As is clear from Table 1, the impedance between the third lead wire 33 and the fifth lead wire 35 and the impedance between the fourth lead wire 34 and the sixth lead wire 36 are substantially equal in the three cables. On the other hand, it can be seen that only the impedance between the first lead wire 31 and the second lead wire 32 is low. Thereby, it turns out that the imbalance arises in impedance by selection of the lead wire of the cable to which each coil of the resolver 13 is connected.

  Further, an electrical error inherent to the resolver 13 is an electrical error that occurs when the sensor cable 5 is not connected, and the exciting coil 38 is connected to the first lead wire 31 and the second lead wire 32 as in the first modification. When the SIN output coil 39 is connected to the third lead wire 33 and the fifth lead wire 35 and the COS output coil 40 is connected to the fourth lead wire 34 and the sixth lead wire 36, the resolver through the sensor cable 5 is connected. The electrical error at 13 outputs was measured (Example 1). Further, as in the above embodiment, the exciting coil 38 is connected to the first lead wire 31 and the second lead wire 32, the SIN output coil 39 is connected to the third lead wire 33 and the fourth lead wire 34, and the COS. When the output coil 40 was connected to the fifth lead wire 35 and the sixth lead wire 36, the electrical error in the output of the resolver 13 through the sensor cable 5 was measured (Example 2). As a comparative example, the SIN output coil 39 is connected to the first lead wire 31 and the second lead wire 32, the excitation coil 38 is connected to the third lead wire 33 and the fifth lead wire 35, and the COS output coil 40 is the fourth lead wire. The electrical error when connected to the lead wire 34 and the sixth lead wire 36 was measured. The results are shown in Table 2.

  As apparent from Table 2, in Example 1 and Example 2, the electrical error in the output of the resolver 13 through the sensor cable 5 was only slightly increased from the electrical error of the resolver 13 without the sensor cable. On the other hand, in the comparative example, it can be seen that the electrical error is greatly deteriorated. From these, it was confirmed that deterioration of the electrical error of the resolver 13 due to the connection of the sensor cable 5 is suppressed by the present invention.

FIG. 1 is a diagram showing a schematic configuration of a brushless motor 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the internal configuration of the motor unit 10. FIG. 3 is a plan view showing the configuration of the resolver 13. FIG. 4 is a cross-sectional view showing the internal configuration of the sensor cable 5. FIG. 5 is a schematic diagram showing the connection of the excitation coil 38, the SIN output coil 39, and the COS output coil 40 to the sensor cable 5. FIG. 6 is a schematic diagram showing connections of the excitation coil 38, the SIN output coil 39, and the COS output coil 40 to the sensor cable 5 in the first modification. FIG. 7 is a schematic diagram showing connections of the excitation coil 38, the SIN output coil 39, and the COS output coil 40 to the sensor cable 5 in the second modification. FIG. 8 is a schematic diagram showing connections of the excitation coil 38, the SIN output coil 39, and the COS output coil 40 to the sensor cable 6 in the third modification. FIG. 9 is a schematic diagram showing the connection of the exciting coil 38, the SIN output coil 39, and the COS output coil 40 to the cable 7 in the fourth modification.

DESCRIPTION OF SYMBOLS 1 ... Brushless motor 3 ... Control part (control means)
5, 6 ... Sensor cable (multi-core cable)
7 ... Cable (multi-core cable)
11 ... Stator (motor stator)
12 ... Rotor (motor rotor)
13 ... Resolvers 31-36, 41-44, 51-60 ... Lead wires (core wires, conductive wires)
38 ... Excitation coil 39 ... SIN output coil (first output coil)
40 ... COS output coil (second output coil)

Claims (5)

A resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, control means for controlling power supply to the motor stator based on a detection signal of the resolver, and an excitation coil of the resolver A multi-core cable that electrically connects the first output coil and the second output coil to the control means,
The multi-core cable has a first lead wire, a second lead wire, a third lead wire, a fourth lead wire, a fifth lead wire, and a sixth lead wire arranged in a circle in the clockwise direction in the cross-sectional structure. Has been
The exciting coil is connected to the first lead wire and the second lead wire,
The first output coil is connected to the third lead wire and the fourth lead wire,
The second output coil is a brushless motor connected to a fifth lead wire and a sixth lead wire . A resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, control means for controlling power supply to the motor stator based on a detection signal of the resolver, and an excitation coil of the resolver A multi-core cable that electrically connects the first output coil and the second output coil to the control means,
The multi-core cable has a first lead wire, a second lead wire, a third lead wire, a fourth lead wire, a fifth lead wire, and a sixth lead wire arranged in a circle in the clockwise direction in the cross-sectional structure. Has been
The exciting coil is connected to the first lead wire and the second lead wire,
The first output coil is connected to the third lead wire and the fifth lead wire,
The second output coil is a brushless motor connected to a fourth lead wire and a sixth lead wire . A resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, control means for controlling power supply to the motor stator based on a detection signal of the resolver, and an excitation coil of the resolver A multi-core cable that electrically connects the first output coil and the second output coil to the control means,
The multi-core cable has a first lead wire, a second lead wire, a third lead wire, a fourth lead wire, a fifth lead wire, and a sixth lead wire arranged in a circle in the clockwise direction in the cross-sectional structure. Has been
The exciting coil is connected to the third lead wire and the sixth lead wire,
The first output coil is connected to the second lead wire and the fifth lead wire,
The second output coil is a brushless motor connected to a first lead wire and a sixth lead wire . A resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, control means for controlling power supply to the motor stator based on a detection signal of the resolver, and an excitation coil of the resolver A multi-core cable that electrically connects the first output coil and the second output coil to the control means,
The multi-core cable has a first lead wire, a second lead wire, a third lead wire, and a fourth lead wire arranged in a circumferential direction in a clockwise direction in the cross-sectional structure,
The exciting coil is connected to the second lead wire and the fourth lead wire,
The first output coil is connected to the first lead wire and the second lead wire,
The second output coil is a brushless motor connected to a second lead wire and a third lead wire . A resolver for detecting a rotation angle of a motor rotor rotated by a magnetic field formed by the motor stator, control means for controlling power supply to the motor stator based on a detection signal of the resolver, and an excitation coil of the resolver A multi-core cable that electrically connects the first output coil and the second output coil to the control means,
The multi-core cable includes a first lead wire, a second lead wire, a third lead wire, a fourth lead wire, a fifth lead wire, a sixth lead wire, a seventh lead wire, an eighth lead wire in a clockwise direction in a cross-sectional structure. The lead wire, the ninth lead wire, and the tenth lead wire are arranged in alignment with the circumference,
The exciting coil is connected to the fifth lead wire and the eighth lead wire,
The first output coil is connected to the fourth lead wire and the sixth lead wire,
The second output coil is connected to the seventh lead wire and the ninth lead wire,
The first lead wire, the second lead wire, the third lead wire, and the tenth lead wire are brushless motors that are used to supply current for the magnetic field formed by the motor stator .

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