JP2009011125A - Motor and bus bar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact motor with a built-in magnetic pole position detection sensor of a rotor, and to provide a bus bar. <P>SOLUTION: The motor comprises: the rotor 12; a stator 11; and the magnetic pole position detection sensor 5. A band-like conductor 3a having a rectangular cross-section is provided with a bus bar 3 having a conductor part extending in a circular arc shape along an end part of the stator, and the magnetic pole position detection sensor 5 is attached to the bus bar. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor and a bus bar, and more specifically to a motor used in an automobile and the like and a bus bar used there.

  In a hybrid vehicle and an electric vehicle, a motor (electric motor) is used for driving the vehicle. Since this motor for driving an automobile is mounted on an automobile, not only high output and high efficiency are naturally required, but also miniaturization and weight reduction are required much more strongly than other applications. For this reason, weight reduction and reduction in units of grams and millimeters are continuously performed without increasing the output, but rather increasing the output.

In recent years, paying attention to its energy efficiency, brushless motors tend to be used in driving parts of hybrid cars, air conditioner compressors, etc., but some proposals have been made for miniaturization of the motor. . For example, a configuration has been proposed in which a printed board including a rotor magnetic pole position detection sensor and an energization control circuit is attached in the vicinity of the motor body (Patent Documents 1 and 2). According to this motor, since it is not necessary to downsize the motor and connect the magnetic pole position detection sensor and the energization control circuit with the lead wire, it is possible to prevent the energization control from being hindered by noise from the lead wire. Also, in order to increase the detection accuracy of the magnetic pole position of the rotor of the three-phase brushless motor, the calculated values and the actual measurement values are averaged for the outputs of the three Hall elements arranged on the printed circuit board for detecting the magnetic pole position of the rotor. Thus, a method for correcting a position (phase) shift has been proposed (Patent Document 3). According to this method, the rotational accuracy of the three-phase brushless motor can be improved.
JP 2001-224156 A JP 2000-324784 A JP 2002-64993 A

  However, the motor described above is a proposal for a configuration of a motor that generates a small amount of current and a small amount of torque, and is not related to a motor that uses a large amount of power to generate a large torque. Current motors for driving automobiles are equipped with a device such as a resolver consisting of a permanent magnet for detection and a detection coil so that the magnetic pole position can be accurately detected on the rotor shaft of the motor. As a result, the motor size was increased and the space utilization efficiency was hindered.

  An object of the present invention is to provide a motor and a bus bar that can enhance space utilization efficiency after incorporating a magnetic pole position detection sensor of a rotor.

  The motor of the present invention is a motor that includes a rotor, a stator, and a magnetic pole position detection sensor that detects the position of the magnetic pole of the rotor. This motor includes a bus bar having a conductive portion in which a strip-shaped conductor extends in an arc shape along an end portion of a stator, and a magnetic pole position detection sensor is attached to the bus bar.

  With the above configuration, the magnetic pole position detection sensor attached to the bus bar at the end of the motor can accurately detect the magnetic pole position using the leakage magnetic flux of the permanent magnet attached to the rotor. For this reason, there is no need to provide a permanent magnet or the like for magnetic pole detection, which is beneficial for miniaturization of the motor and can improve space utilization efficiency.

  Further, the magnetic pole position detection sensor can be attached to the bus bar so as to overlap the rotor as viewed along the axis of the motor. Thereby, the magnetic pole position detection sensor can be provided without spatially interfering with other members. For example, the magnetic pole position detection sensor can be arranged so as to overlap the radial position of the permanent magnet embedded in the rotor, and the magnetic pole position can be detected with higher accuracy. Further, since the position is detected by measuring the leakage magnetic flux from the rotor, it is not necessary to attach any other special permanent magnet to the rotor shaft, so that the number of parts can be reduced and the motor assembly process can be simplified.

  A magnetic flux guide path of a ferromagnetic material can be attached to the bus bar, and a magnetic pole position detection sensor can be incorporated in the magnetic flux guide path. With this configuration, for example, a magnetic flux guiding path is formed between two adjacent permanent magnets among a plurality of permanent magnets embedded in the rotor, so that the leakage magnetic flux from the permanent magnet can be efficiently positioned at the magnetic pole position. It can lead to a detection sensor. As a result, the magnetic pole position detection accuracy can be increased.

  The magnetic flux guide path may have a protrusion that is positioned at least one end of the magnetic flux guide path so as to protrude toward the rotor. As a result, leakage flux can be collected more efficiently in the magnetic flux guide path, and the accuracy of magnetic pole position detection can be improved.

  The bus bar of the present invention includes a conductive portion in which a strip-shaped conductor extends in an arc shape, and a magnetic pole position detection sensor.

  With the above configuration, the magnetic pole position detection sensor can be arranged by assembling the bus bar to the motor, so that the number of parts of the motor can be reduced and the brushless motor can be efficiently assembled. Further, since it is not necessary to provide a permanent magnet or the like for detecting the magnetic pole position of the rotor, it is possible to reduce the motor size and contribute to increasing the space utilization efficiency. The magnetic pole position detection sensor is preferably fixed to, for example, an insulating housing that houses the conductive portion.

  In addition, a magnetic flux guiding path made of a ferromagnetic material can be provided, and a magnetic pole position detection sensor can be incorporated in the magnetic flux guiding path. Thereby, more magnetic flux can be guide | induced to a magnetic pole position detection sensor, and the precision of magnetic pole position detection can be improved.

  The magnetic flux guiding path may have a protruding portion protruding at at least one end of the magnetic flux guiding path so as to intersect a plane extending between the arc forming the shape of the conductive portion and the center of the arc. . Thereby, more magnetic flux can be more efficiently guided to the magnetic pole position detection sensor.

  According to the motor and bus bar of the present invention, it is possible to reduce the size of the motor and increase the space utilization efficiency after incorporating the magnetic pole position detection sensor of the rotor.

  FIG. 1 is a schematic diagram of a motor 10 according to an embodiment of the present invention. The motor 10 is a brushless motor known as an embedded magnet type synchronous motor or an IPM (Interior Permanent Magnet) motor. However, the motor of the present invention is not limited to an IPM motor, and is an SPM (permanent magnet) arranged on the rotor surface. Surface Permanent Magnet) or a surface magnet type synchronous motor may be used. In FIG. 1, the rotor 12 has a number of permanent magnets 13 corresponding to the magnetic poles embedded therein. A current flows through the stator 11 in synchronism with the rotation of the rotor 12 via the bus bar 3, thereby generating torque in the rotor 12. In order to flow a current in accordance with the rotation angle of the rotor 12, a current control circuit (not shown) needs to know the rotation angle of the rotor 12 accurately. For this purpose, the magnetic pole position detection sensor 5 of the rotor 12 is used. The present embodiment is characterized in that the magnetic pole position detection sensor 5 including the magnetic flux guide path 7 is attached to the bus bar 3.

  The place where the magnetic pole position detection sensor 5 and the magnetic flux guide path 7 are arranged is originally an empty space in a motor for automobiles that is so compacted, and the magnetic pole position detection sensor 5 and the like are arranged in the empty space. Can be used more effectively. Conventionally, a resolver, which is a magnetic pole position detection sensor or a magnetic pole position detection device, is arranged in the space A or the like. However, by taking the configuration as shown in FIG. 1, the space A can be used as an arrangement place for another component. Alternatively, it is possible to review the structure of the entire motor on the assumption that the space A is an unnecessary space. That is, space utilization efficiency can be increased.

  The motor 10 shown in FIG. 1 is an embedded magnet type rotor in which a permanent magnet 13 is embedded in a rotor 12, and (1) even if it rotates at a high speed, compared with a motor of a type in which a permanent magnet is attached to the rotor surface. This is advantageous in that the permanent magnets can be prevented from scattering and (2) the reluctance torque resulting from the auxiliary salient poles between the permanent magnets can be used. The permanent magnet 13 has a length substantially equal to the rotor length in parallel with the shaft 14 of the rotor 12. As the permanent magnet 13, a rare earth magnet using Sm, Co, or the like, in particular, a high performance magnet using Nd is preferably used.

  In the motor 10 described above, an aluminum frame is used for the frame portion that supports the rotor shaft 14, and not only the weight can be reduced, but also the attraction of magnetic flux and the generation of braking force with the rotor can be prevented. The frame portion may be made of steel plate or resinous depending on the type of motor. A water jacket 19 is disposed in contact with the outer periphery of the stator 11 to suppress a temperature rise due to heat generated by the motor 10.

  FIG. 2 is an enlarged view showing the arrangement of the magnetic pole position detection sensor 5 of FIG. The magnetic pole position detection sensor 5 is continuous with the magnetic flux guide path 7 and is fixed to the bus bar 3. The bus bar 3 includes a conductive portion 3a for three-phase AC power and an insulator 3b that covers the conductive portion 3a. Although only three conductive portions 3a are shown in FIG. 2, the conductive portion 3a is normal because a conductive portion at a neutral point is arranged in addition to this, but the illustration is omitted. The bus bar 3 extends along the stator 11 on the end surface side of the stator 11 and has an arc shape (ring shape). The rotor 12 is located on the inner peripheral side of the stator 11 arranged in an annular shape. In the rotor 12, the above-described permanent magnet 13 is embedded with a length substantially equal to the length of the rotor 12. The rotor 12 receives the magnetic flux from the stator 11 synchronized with the rotation thereof, and is driven to rotate by the interaction between the magnetic flux, the permanent magnet 13 and the salient poles therebetween.

  The permanent magnet 13 is embedded in the rotor 12 corresponding to the number of stator poles of the motor 10. The stator 11 includes a core 11a and a coil 11b wound around the core 11a corresponding to the number of poles. In accordance with the rotational position of the rotor 12 or the permanent magnet 13, the coil 11b of the divided part of the stator 11 is controlled so that a current flows in order, and a predetermined torque is generated in a certain direction without interruption. In order to realize such control, the magnetic pole position detection sensor 5 is arranged. The present embodiment is characterized in that the magnetic pole position detection sensor 5 is attached to the bus bar 3 as described above. The magnetic pole position detection sensor 5 normally uses a Hall element for detecting the magnetic flux position in order to detect the passage of the rotating permanent magnet 13 by capturing the leakage magnetic flux of the permanent magnet 13 of the rotor 12. . For this reason, the Hall element 5 may be used alone, but in order to accurately detect the passage time of the permanent magnet 13 of the rotor 12 rotating at high speed, a magnetic circuit ( It is preferable to configure the magnetic flux guide path 7) to guide the leakage magnetic flux to the Hall element 5 collectively without dissipating.

  A motor for driving a vehicle body used in an electric vehicle, a hybrid car, or the like is required to have a high torque and has a tendency to increase the number of magnetic poles. Therefore, the interval between adjacent permanent magnets 13 is reduced. In order to detect the position of the permanent magnet 13 during rotation with high accuracy, conventionally, the position of the magnetic pole is faithfully reflected on the rotor shaft 14 on the outside of the motor body (for example, location A in FIG. 1). The permanent magnet is arranged with high accuracy and the rotational position of the permanent magnet is detected. In the present embodiment, as shown in FIG. 2, the magnetic flux from the permanent magnet 13 of the rotor 12 is directly captured for attachment to the bus bar 3 inside the motor body. Therefore, as described above, the space A in FIG. 1 can be used for another purpose.

  Since the tip of the magnetic flux guide path 7 is preferably close to the end face of the rotor 12 or the end of the permanent magnet 13, the gap G is made as small as possible in consideration of the deviation of the end face during rotation. In addition, since the Hall element 5 itself can be regarded as a gap, the length of the Hall element 5 is preferably shorter. Further, it is preferable to consider the connection between the Hall element 5 and the magnetic flux guide path 7 so as not to increase the magnetic resistance. Since the magnetic resistance is approximated by (magnetic flux induction path length) / (magnetic permeability × cross-sectional area), the magnetic flux induction path 7 is made of a material having a high (ratio) permeability, particularly a high (ratio) permeability in a low magnetic field. For example, low carbon iron, pure iron, silicon steel, permalloy or the like can be used. The Hall element 5 is preferably provided with a protective insulating film. In attaching the Hall element 5 to the bus bar 3, it is preferable to provide a terrace-shaped attachment portion 3 s on the inner peripheral side of the bus bar 3. The mounting portion 3s may have a terrace shape or a holding spring shape that elastically restrains the Hall element 5 and the magnetic flux guiding path 7.

  FIG. 3 is a view showing a mounting structure of the hall element 5 incorporated in the magnetic flux guide path 7 to the bus bar 3. A terrace-shaped attachment portion 3s is provided at the bus bar portion where the hall element 5 is attached so as to protrude to the inner peripheral side. The Hall element 5 is preferably firmly fixed to the attachment portion 3s together with the magnetic flux guide path 7 by an adhesive or mechanical means (not shown). The attachment portion 3s is also preferably formed of the same type of insulating resin as the insulator 3b of the bus bar 3.

  The magnetic flux guide path 7 is formed so that the legs 7a and 7b are not connected between the same polarities of the permanent magnets but are spaced so as to connect the different polarities. This is preferable because it occurs. Therefore, the size, material, performance, and the like of the magnetic flux guide path 7 and the Hall element 5 need to be changed according to the type of motor to be mounted. The magnetic pole detection sensor 5 changes the number of arrangement and the arrangement mode according to the number of magnetic poles and the target control accuracy. FIG. 4 is a diagram showing an example in which four Hall elements 5 are arranged when the number of permanent magnets arranged in the rotor 12 is eight. In FIG. 4, the bus bar 3 is omitted to avoid complication.

  So far, the motor 10 has been mainly described. However, it is naturally possible to put the bus bar 3 to which the Hall element 5 and the magnetic flux guide path 7 are attached into the distribution path as an independent product. By using such a bus bar with a magnetic pole position detection sensor, the number of parts can be reduced, and the steps of attaching permanent magnets to the rotor shaft that require high accuracy, arranging the measurement coils, etc. are omitted, and the motor assembly process Can be greatly simplified. Moreover, it can contribute to the miniaturization of a motor or the improvement of space utilization efficiency.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  By using the motor and bus bar of the present invention, the motor including the power supply / distribution unit to the motor can be miniaturized, the space utilization efficiency can be improved, and the process of mounting the motor on an automobile or the like can be simplified. .

It is the schematic which shows the motor in embodiment of this invention. It is a figure which shows the attachment structure of the magnetic pole position detection sensor of the motor shown in FIG. It is a figure which shows the positional relationship of a magnetic pole position detection sensor, a bus bar, and a rotor. It is a figure which shows the positional relationship of a magnetic pole position sensor and the permanent magnet of a rotor.

Explanation of symbols

  3 bus bar, 3a conductive portion, 3b insulator, 3s mounting portion, 5 magnetic pole position detection sensor, 7 magnetic flux guide path, 7a, 7b tip (leg) of magnetic flux guide path, 11 stator, 11a core, 11b coil, 12 rotor, 13 permanent magnet, 14 rotor shaft, 19 water jacket, G gap.

Claims (7)

A motor comprising a rotor, a stator, and a magnetic pole position detection sensor for detecting the position of the magnetic pole of the rotor,
A belt-shaped conductor comprising a bus bar having a conductive portion extending in an arc along the end of the stator;
The motor, wherein the magnetic pole position detection sensor is attached to the bus bar.   2. The motor according to claim 1, wherein the magnetic pole position detection sensor is attached to the bus bar so as to overlap the rotor when viewed along the axis of the motor.   3. The motor according to claim 1, wherein a magnetic flux guiding path made of a ferromagnetic material is attached to the bus bar, and the magnetic pole position detection sensor is incorporated in the magnetic flux guiding path.   4. The motor according to claim 3, wherein the magnetic flux guiding path has a projecting portion positioned so as to project toward the rotor at at least one end of the magnetic flux guiding path. A conductive portion in which a strip-shaped conductor extends in an arc shape;
A bus bar comprising a magnetic pole position detection sensor.   6. The bus bar according to claim 5, further comprising a magnetic flux guiding path made of a ferromagnetic material, wherein the magnetic pole position detection sensor is incorporated in the magnetic flux guiding path. The magnetic flux guiding path has a protruding portion protruding at at least one end of the magnetic flux guiding path so as to intersect a plane extending between an arc forming the shape of the conductive portion and a center of the arc. The bus bar according to claim 6.

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