JP3455089B2 - Motor coil unit with detection coil - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor coil unit incorporated in a so-called axial gap type brushless DC motor (brushless DC motor), and more particularly to a motor driving coil. A rotational speed detection coil and / or
Alternatively, the present invention relates to noise reduction of a motor coil unit having a detection coil provided with a rotor position detection coil. 2. Description of the Related Art For example, a brushless DC is used as an actuator for audio equipment, visual equipment, OA equipment and the like.
Although motors are frequently used, recently, thinner motors have been demanded in response to the demand for smaller and lighter devices. To meet this demand,
Motor driving coil, frequency generator coil (hereinafter referred to as FG coil) and rotor position detecting coil (hereinafter referred to as PG coil) used for detecting the number of rotations of the motor.
Are manufactured in a thin, flat shape by printed wiring technology,
There is a tendency to widely use a motor in which a product obtained by laminating them is integrated into a motor. FIG. 5A shows a conventional flat-type motor driving coil unit (hereinafter, referred to as a coil unit) using this type of printed wiring technology.
FIG. 1 is a plan view showing an example of a printed coil unit 1). A motor coil pattern 2 in which conductors are formed in a spiral shape one by one is arranged on the front and back surfaces of a ring-shaped substrate 3 at equal intervals. . The thin printed coil unit 1 formed as described above is sandwiched between a plurality of magnetized rotor magnets 4 and a stator yoke 5 as shown in FIG. And an axial gap type brushless small motor having the following characteristics. A small axial gap type brushless motor in which such a thin print coil unit 1 is sandwiched between a rotor magnet 4 and a stator yoke 5 is lightweight and has a low moment of inertia. It is difficult to expect the effect of suppressing the unevenness of rotation due to the moment of inertia, so that the control of the rotation speed and the rotation position of the motor and the sensor therefor are important. As a means for detecting the rotational speed, for example, as shown in FIG. 6A, an FG coil 6 which is a frequency generating sensor formed in a rectangular pattern on an annular sheet is generally used. ing. This sheet is laminated and adhered to another sheet (layer) on which the motor driving coil pattern 2 is formed as shown in FIGS. 6B and 6C, and three prints are laminated via an insulating layer. Coil unit. When the axial gap type brushless small motor assembled as shown in FIG. 5B is operated using this print coil unit, the rotor magnet 4 moves on the FG coil 6 of the print coil unit 1 and Is motor 1
A voltage having a half wave number of the number of poles of the rotor magnet 4 is generated for each rotation. This FG output is converted into a DC voltage proportional to the frequency using an FV converter, compared with a reference voltage, and controlled by a FG servo method that controls the voltage applied to the motor according to the differential output. Can be kept constant. [0005] Video (analog, digital) and D
When the print coil unit 1 is used for a cylinder motor of an AT (digital audio tape) or a DDS (digital data streamer), a PG coil 7 as shown in FIG. 7 is used to detect the position of the motor rotor . . When using this PG coil 7,
In addition to the driving magnetic pole of the rotor magnet 4 having a plurality of magnetic poles, one or more magnetic poles are additionally provided on the circumference thereof, and a pulse is generated each time the magnetic pole portion passes over the PG coil 7. Is used to detect that the rotor magnet 4 has passed a predetermined position. The FG coil 6 and the PG coil 7 may be collectively formed on one side of one sheet (layer),
Further, the FG coil 6 is formed together with the motor coil pattern 2 on one sheet (one layer), and the FG coil 6 is formed together with the motor coil pattern 2 on another sheet (another layer).
The G coil 7 may be formed. [0007] The magnetic poles for applying a magnetic field to the detection coils 6 and 7 are respectively provided to the rotor magnets. As for the FG coil, there is a type in which the magnetic field of the motor driving coil can be diverted as it is as in the case of the print coil unit in FIG. 6, and in this case, the magnetic field region of the motor coil pattern 2 and the magnetic field region of the FG coil 6 are Is the same. On the other hand, a magnetic field dedicated to the FG coil may be provided inside or outside the magnetic field of the motor driving coil. For example, in the case where the pattern of the FG coil 6 is outside the motor coil pattern 2 as in the print coil unit shown in FIG. 7, a magnetic pole dedicated to the FG coil 6 is provided on the outer periphery of the rotor magnet. In that case, the number of magnetic poles for the FG coil is made larger than the number of magnetic poles for the motor drive coil, and 1
Increasing the number of magnetic pole changes per rotation can increase the accuracy of detecting the rotational speed detected by the FG coil. Since the purpose of the magnetic field of the PG coil is to generate about one pulse during one rotation of the rotor magnet, it is different from the magnetic poles for the FG coil and the motor drive coil. A magnetic field is passed through the magnetic poles N and S once per rotation of the rotor magnet. Therefore, the region of the magnetic field of the PG coil is set outside or inside the region of the magnetic field for the motor driving coil and the region of the magnetic field for the FG coil. [0009] Recently, brushless D
While the miniaturization of devices equipped with C motors is progressing rapidly, and the size of motors is also progressing accordingly, the performance required for motors, such as torque and rotational accuracy, is the same as before miniaturization. It has become difficult to obtain sufficient characteristics with the print coil units described above. By the way, the size of the motor itself was about 40 mm in diameter for a video cylinder motor.
The current digital video has a diameter of 19 mm.
Even with such a small-diameter motor, in order to obtain the same torque as a large motor, the magnetic gap must be increased by narrowing the magnetic gap of the rotor magnet. Therefore, the thickness of the print coil unit is 0.2 mm to 1.5 mm including the FG coil and the PG coil, and the diameter is 17 mm to 30 mm, which is almost the same as that of the motor. As described above, in the presently required print coil unit, the motor coil pattern and the FG coil and / or the PG coil are arranged in an extremely small area, and a strong magnetic field must be used. is there. Furthermore, since the sizes of the FG coil and the PG coil are small, it is necessary to efficiently arrange conductor wiring patterns for obtaining necessary signals in places where the magnetic field is as strong as possible. The FG coil and the PG coil generate a signal in each effective coil area in accordance with the rotation of the rotor magnet, and the signal is led to each external connection terminal using a connection line. However, in the case of a print coil motor, the magnetic field region sandwiching the print coil unit is extremely thin. Moreover, each coil is arranged in a plane. For this purpose, the connection line must pass through the magnetic field region of another coil before reaching the external connection terminal. Thus, in the conventional print coil unit, the generation of noise due to the interference of the magnetic field between the coils inevitably occurs at the connection line portion, which may hinder the rotation speed control and the rotation position control of the motor. There is a problem that there is no. Accordingly, the present invention has been made in view of such an unsolved problem in the related art, and by improving a wiring pattern of connection lines in a detection coil used for rotation control and position control, noise has been improved. It is an object of the present invention to provide a motor coil unit with a detection coil capable of suppressing the occurrence of the above. [0014] In order to achieve the above object, the present invention according to claim 1 comprises a motor driving coil,
Rotor position detection coil or rotation speed detection coil
At least one of the modules with a detection coil
The detection coil and its
If the connecting wire connecting the terminals crosses the area of another coil
In the opposite direction to the coil unit radial direction
To a zigzag shape with an incident angle in the range of 5 to 85 degrees.
The connection line is provided. That is, in both the FG coil and the PG coil, which are detection coils, the magnetic field for generating an electromotive force in those coils may be the same as the magnetic field of the motor driving coil, but is often large. Are different. Further, even if the magnetic field is the same, there is always a connection line for connecting the conductor circuit portion for generating a signal to the detection coil to the external connection terminal, and the connection line is connected to another coil (for example, a motor driving coil). And other detection coils). In any case, the passage of a magnetic field unrelated to the connection line causes noise at the connection line portion. The inventors of the present invention have studied the conditions under which this noise is generated. As a result, the +,
-When the connection line on which the (two) lines are arranged is arranged at an angle of less than 5 degrees with respect to the coil unit radial direction, for example, 0 degrees, that is, parallel to the radial direction, each time the boundary of the magnetic pole passes the radius, It turned out that noise was generated. In other words, if the connecting wires are arranged at an angle of 5 degrees or more with respect to the radial direction of the coil unit, no noise is detected. The larger the angle, the lower the possibility of noise generation. However, if the connection wires are routed at an excessively large angle, the degree of freedom in coil arrangement becomes extremely poor, and coil arrangement becomes difficult. Therefore, from a practical point of view, the upper limit of the inclination angle of the connection line is preferably set to 85 degrees. [0020] Then, the connection line, whereupon a zigzag connection lines angled in the range of 5 to 85 degrees in the opposite direction alternately with respect to the coil unit radially, thereby preventing the same noise. In that case, it was also found that particularly remarkable noise prevention effects could be obtained by connecting each of the zigzag angles at a substantially rounded angle. Embodiments of the present invention will be described below with reference to the drawings. The same or corresponding parts as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 shows a motor coil unit with a detection coil.
Plan view of a sheet of FG coil 6 is arranged to constitute the door, FIG. 2 (a), (b) is a plan view of a sheet motor driving coil is formed combining overlapping thereto. In the sheet shown in FIG. 1, an FG coil 6 formed by connecting 20 rectangular detection patterns in a circle is disposed on the inner peripheral side. External connection terminals 6t, 6t for the FG coil 6 are provided on the outer peripheral side. Then, the FG coil 6 on the inner circumference and the external connection terminals 6t on the outer circumference,
6t are connected across the sheet in the radial direction by a pair of connecting wires 10 of +-. In the sheet shown in FIG. 2A, a spiral motor coil pattern 2 having six poles is annularly arranged on the inner periphery. The same motor coil pattern 2 is arranged on the sheet of FIG. 2B for three phases U, V, and W, with two poles per phase. Two sheets having the motor coil pattern 2 on the front and back are superposed and adhered to each other to form two layers, and the sheet of FIG. 1 is further stacked to form a three-layer print coil unit 1. In this embodiment, the region of the magnetic field for generating an electromotive force in the FG coil 6 for detecting the number of rotations of the motor is on the inner peripheral side in common with the region of the magnetic field for driving the motor. The magnetic field (of a magnetic pole separately provided on the outer periphery of the rotor magnet) for generating an electromotive force in the coil 7 is on the outer peripheral side. The connection line 10 of the FG coil 6 is
The connection line 10 crosses the magnetic field region for the coil 7, and the connection line 10 at the crossing point is inclined by 78 degrees with respect to the radial direction of the coil unit 1 so that the external connection terminal 6
t, 6t. The above-described motor coil pattern 2, FG coil 6, PG coil 7 and the like may be manufactured by etching, plating, or a combination thereof, as in the prior art.
In particular, when it is intended to improve the characteristics of the actuator and the accuracy of the FG and PG coils, it is most effective to form them by plating. For example, taking the motor coil sheet of FIG. 2 as an example, a photomask such as the motor coil pattern 2 on the front side is designed by a conventional method, and the surface on which the conductive pattern of the conductive substrate is to be formed using this photomask. Next, a photoresist pattern corresponding to each coil pattern is formed by the technique of the printed wiring technology.
Next, electrolytic copper plating is performed while energizing the conductive substrate on which the pattern is formed to form a predetermined conductor pattern (copper pattern). In addition, the conductor pattern of the motor coil on the back side (not shown) is formed on another conductive substrate surface in the same procedure. An insulating varnish is applied and cured on the surface of each conductive substrate on the side where the conductive pattern is formed. With the surface coated with the insulating varnish inside, 2
The two conductive substrates are bonded to each other with an epoxy-based adhesive sandwiching a glass cloth or an insulating film sheet therebetween. Next, if necessary, a hole is made in a portion to be connected to the through hole, and a catalyst treatment for chemical plating is performed. Next, the conductive substrate is removed by etching, and chemical plating is performed. Electrolytic copper plating is performed using the thus obtained sheet having the coil pattern 2 on both sides as electrodes. Through these steps, the sheet shown in FIG. 2A having the motor coil patterns 2 on both front and back surfaces is manufactured. The sheet of FIG. 2B is manufactured through the same process. Note that the sheet of FIG. 2A and the sheet of FIG. 2B are laminated with a two-layer structure by bonding with an insulating resin. The conductor pattern (copper pattern) of the detection coil in FIG. 1 can also be formed on the conductive substrate surface in substantially the same manner. These are laminated as follows via an insulating resin to complete the motor coil unit 1 with the detection coil. That is, the conductive pattern in which the copper pattern of the FG coil 6 shown in FIG. 1 is formed on the surface of the sheet (FIG. 2A) having the motor coil pattern 2 on the front and back surfaces prepared in the above-described process. The substrates are stacked and bonded with an insulating resin. Next, the conductive substrate is removed by etching. After that, a through-hole land portion for connection is opened, solder is poured in, and interlayer connection is performed via an insulating layer. The printed coil unit 1 of the present invention thus obtained is fixed on the stator yoke plate 5 and is opposed to the rotor magnet 4 with a slight gap therebetween to produce an axial gap type brushless DC motor. And an operation test. When the motor is started and the rotor magnet is turned, the voltage generated in the FG coil 6 is as shown in FIG.
A voltage output was obtained. The FG voltage output of FIG. 3B is shown in FIG.
This is a conventional example having the FG coil pattern shown in FIG. Here, the FG coil 6 and the external connection terminal 6t,
6t is parallel to the radial direction of the print coil unit, that is, each inclination is 0 degrees.
Arranged in degrees. Let the magnetic field region of the magnetic pole of the PG coil be F
The noise signal N, which is considered to have been generated when the G-coil connection line 10 crossed, was periodically carried, so that the FG coil 6 could not control the rotation speed. FIG. 4 shows an embodiment of the present invention. This figure shows an enlarged view of only the FG coil sheet of the print coil unit 1 composed of three conductor layers. In this embodiment, the connection wire 10 of the FG coil 6 is a PG
It is different from the rotational speed detecting coil of FIG. 1 in that the coil is disposed in a zigzag shape at a position crossing the magnetic field region of the coil . That is, the two connection wires 10 are alternately bent in a direction at an angle of 5 degrees or more with respect to the radial direction of the coil unit and in the opposite direction.
It has a zigzag shape in which the corners of the bent portion are connected with almost no roundness. Also in the case of this embodiment, the output voltage of the FG coil 6 has no noise and an extremely good signal is obtained. In the motor coil unit with a detection coil to which the present invention can be applied, the number of spiral turns of the motor coil pattern 2 and the method of connecting the spirals are not limited to the above-described embodiment, and the shape of the spiral is not particularly limited. In short, any shape may be used as long as it generates a magnetic field when energized. Further, through holes for connecting the conductor patterns of each coil on both surfaces of the insulating substrate may be provided at portions other than the center of the spiral as appropriate. Further, it is not necessary to limit the number of sheets on which the motor coil pattern is formed on both the front and back surfaces, and the number may be arbitrary. As described above, in the motor coil unit with the detecting coil according to the first aspect, the connecting line connecting the detecting coil and the terminals thereof is connected to the other coil. Since the connection angle is arranged to be inclined at an angle of 5 to 85 degrees with respect to the coil unit radial direction at a portion crossing the region, noise generation when the connection line of the detection coil passes through another coil region is suppressed. As a result, it is possible to provide an axial gap type brushless DC motor capable of controlling the rotation speed and the position with high accuracy. [0036] Then, in a place where the connecting line connecting the detecting coil and the terminals thereof crosses the area of the other coil, the connecting line is arranged in a zigzag shape. The effect of maintaining a high degree of freedom in coil arrangement is also achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pattern diagram of a rotation speed detecting coil for explaining the present invention . FIG. 2 is a pattern diagram of a layer on which a motor driving coil combined with the detection coil of FIG. 1 is arranged. 3A and 3B are diagrams showing a waveform of an output voltage of an FG coil when a rotor magnet is rotated, wherein FIG. 3A is an output voltage of an FG coil of the present invention, and FIG. 3B is an output voltage of an FG coil of a conventional example. . FIG. 4 is a pattern diagram of a rotation speed detecting coil according to the embodiment of the present invention . FIG. 5 is an example of a flat type brushless motor using a conventional print coil unit, where (a) is a plan view of the print coil unit and (b) is an exploded view of the motor. 6A and 6B are exploded views of a print coil unit in which a conventional detection coil is arranged, wherein FIG. 6A is a pattern of a rotation speed detection coil, and FIGS. 6B and 6C are patterns of a motor drive coil. FIG. 7 is an exploded view of another conventional print coil unit, in which (a) shows a pattern of a motor driving coil and an FG coil, and (b) shows a pattern of a motor driving coil and a PG coil. [Description of Signs] 1 Print coil unit 2 Motor driving coil pattern 4 Rotor magnet 5 Stator yoke plate 6 Rotation speed detection coil (FG coil) 6t FG external connection terminal 7 Rotor position detection coil (PG coil) 7t PG external connection terminal 10 (FG coil) connection line θ connection line connection angle

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 3/26

Claims (1)

(57) [Claims] [Claim 1] Motor drive coil and rotor position detection
At least one of the following coils:
Motor coil unit with detection coil with
In Tsu DOO, connection line other for connecting between the terminal and the detecting coil
When crossing the coil area, the coil unit radial direction
Alternately in the opposite direction with an incident angle in the range of 5 to 85 degrees
The connection wire is arranged in a zigzag shape having
Motor coil unit with detection coil.