JPH099577A - Rotation detecting device and mounting method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] A holder for holding a magnetic sensitive element can be downsized or abolished, and the mounting position of the magnetic sensitive element with respect to the FG magnet can be easily adjusted. A printed wiring board 13 is locked to a protrusion 19 provided on the substrate 1, the printed wiring board 13 is moved on the substrate 1 with the protrusion 19 as a fulcrum, and the printed wiring board 13 is provided on the printed wiring board 13. Sensor 11 for speed detection
Are arranged to face the FG magnet 10 with a predetermined distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for detecting the rotation speed of a motor and a mounting method thereof.

[0002]

2. Description of the Related Art For example, a video tape recorder (hereinafter referred to as V
It is called TR. ), A capstan motor is used as a motor for feeding the tape. As such a capstan motor, for example, as shown in FIG. 6, a so-called flat type in which a rotor yoke having a drive magnet provided so as to face a coil arranged on a substrate is rotated by a rotating shaft is used. A brushless motor structure is generally used.

This capstan motor comprises a drive coil 102 fixed on a substrate 101 and a drive coil 10
2, a rotor yoke 104 provided with a drive magnet 103 arranged to face each other with a minute gap, and a rotary shaft (not shown) attached to the rotor yoke 104,
It comprises a pulley (not shown) attached to the tip of this rotary shaft.

The drive coil 102 is formed, for example, as a coil formed by winding a winding in a substantially trapezoidal plane shape, and is fixed on a substrate 101 made of iron or the like on which a wiring circuit pattern is formed. The drive coil 102 functions as a stator.

The rotor yoke 104 is formed as a flat cylinder having a low height and one side open, and is fixed to one end of a rotary shaft that is rotatably supported by a bearing housing (not shown) screwed to the substrate 101. .

The drive magnet 103 is formed as a disk-shaped magnet in which S poles and N poles are alternately magnetized, and is fixed to the inner surface of the rotor yoke 104.

The height of the rotor yoke 104 can be adjusted by a thrust adjusting screw provided on the other end side of the rotating shaft. That is, the drive magnet 103 is adjusted by adjusting the thrust adjusting screw.
The facing distance between the drive coil 102 and the drive coil 102 can be changed.

By the way, in this capstan motor,
A speed sensor for detecting the rotation speed of the motor is provided. The speed sensor includes an FG magnet 105 provided on the outer periphery of the rotor yoke 104, and a magnetically sensitive element 106 such as an MR element provided facing the FG magnet 105. This speed sensor is FG
The magnetic flux magnetized by the magnet 105 is applied to the magnetic sensitive element 10.
By detecting by 6, the rotation speed of the motor is detected.

The magnetic sensitive element 106 is an FG magnet 1.
Since it is necessary to surely pick up the magnetic flux magnetized by 05, it is necessary to dispose the magnetic flux close to and facing the FG magnet 105. Therefore, a holder 107 made of a molded body is provided on the substrate 101, and the magnetic sensitive element 106 is provided on the holder 107.

The magnetic sensitive element 106 is attached to the substrate 10.
In order to electrically connect with the wiring circuit pattern formed on the wiring 1, a lead wire 108 is attached to the magnetic sensitive element 106, and the lead wire 108 is connected to the wiring circuit pattern by solder 109.

[0011]

By the way, in order to perform a highly accurate control, the outer peripheral surface of the FG magnet 105 is provided with 3
Magnetize 60 to 720 equal NS,
The magnetic sensitive element 106 should be the FG magnet 105 as much as possible.
Need to be close to. For example, the facing distance of the magnetic sensitive element 106 to the FG magnet 105 is 0.1 to 10.
It is about 0.15 mm.

The magnetic sensitive element 106 is replaced by the FG magnet 10.
5, the holder 107 is mounted on the substrate 101 by screws 110 with a spacer of about 0.1 mm sandwiched between the magnetic sensitive element 106 and the FG magnet 105 as shown in FIG. Then, the lead wire 108 is connected to the pattern of the printed wiring board formed on the substrate 101 with solder 109.

However, in order to set the facing distance of the magnetic sensitive element 106 to the FG magnet 105 to be about 0.1 mm, a holder 107 which is large to some extent is necessary for adjustment. However, even if the large holder 107 is used, it is difficult to set the facing distance of the magnetic sensitive element 106 to the FG magnet 105 to about 0.1 mm. On the other hand, the larger the holder 107,
A space for mounting the holder 107 is required, which hinders downsizing of the motor.

Further, the soldering work after fixing the holder 107 is a work by human hands. Therefore, the soldering work becomes troublesome and the productivity cannot be improved.

Therefore, in order to solve the above-mentioned conventional technical problems, the present invention enables miniaturization of a holder for holding a magnetically sensitive element or elimination of the holder, and an FG magnet for the magnetically sensitive element. An object of the present invention is to provide a rotation detecting device and a mounting method thereof, which can facilitate the mounting position adjustment.

[0016]

A rotation detecting device according to the present invention is fixed to one end of a rotary shaft, and is provided with a drive magnet that rotates with the rotary shaft, and a rotor yoke. The rotor yoke is fixed to a substrate so as to face the drive magnet. The rotation speed of a so-called flat type motor including the drive coil and an FG magnet provided around the outer periphery of the rotor yoke is detected. In this rotation detecting device, in order to miniaturize the holder for holding the speed detecting sensor, the printed wiring board is locked to the engaging portion provided on the substrate, and the printed wiring board is mounted on the substrate with the engaging portion as a fulcrum. By moving it above, the speed detecting sensor provided on this printed wiring board is arranged to face the FG magnet with a predetermined distance. Further, in order to omit the holder for holding the speed detecting sensor, the speed detecting sensor is directly fixed to the printed wiring board.

On the other hand, in the method of mounting the rotation detecting device for detecting the rotation speed of the flat type motor, the engagement provided on the substrate is provided so that the facing distance of the speed detecting sensor with respect to the FG magnet can be easily adjusted. The printed wiring board is locked to the part, and the printed wiring board is moved on the board with the engaging portion as a fulcrum, and the speed detection sensor provided on the printed wiring board is provided with a predetermined distance from the FG magnet. To face each other. Further, in order to omit the holder for holding the speed detecting sensor, the speed detecting sensor is directly fixed to the printed wiring board.

[0018]

In the rotation detecting device according to the present invention, the speed detecting sensor is fixed to the printed wiring board provided on the substrate instead of fixing the speed detecting sensor to the substrate provided with the motor. The detection sensor can be arranged on the printed wiring board roughly to some extent, and the holder for holding the speed detection sensor can be downsized. In addition, by fixing the speed detecting sensor directly to the printed wiring board, a holder is not required.

On the other hand, in the method of manufacturing the rotation detecting device according to the present invention, the printed wiring board is locked to the engaging portion provided on the substrate, and the printed wiring board is moved on the substrate using the engaging portion as a fulcrum. Since the speed detection sensor provided on the printed wiring board is arranged to face the FG magnet with a predetermined distance,
The facing distance of the speed detection sensor to the FG magnet can be easily adjusted.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. In this embodiment,
It is an example in which the present invention is applied to a capstan motor of a flat brushless motor used for a VTR.

As shown in FIGS. 1 to 3, the capstan motor includes a drive coil 2 fixed on a substrate 1 and a drive magnet 3 which is arranged to face the drive coil 2 with a minute gap. The rotor yoke 4 is provided with a rotating shaft 5 attached to the rotor yoke 4, and a pulley 6 attached to the tip of the rotating shaft 5.

As shown in FIGS. 1 and 3, the substrate 1 is formed by punching a metal plate made of iron or the like into a predetermined shape. Then, the main surface 1a of the substrate 1
As shown in FIG. 3, a plurality of drive coils 2 are fixed to each other at predetermined intervals with an adhesive or the like. The drive coil 2 functions as a stator, and is formed by winding a winding into a substantially trapezoidal plane.

The drive magnet 3 is, as shown in FIG.
It is formed as a ring magnet having a circular hole in the center and is fixed to the top plate portion inside the rotor yoke 4. An N pole and an S pole are alternately magnetized on the surface of the drive magnet 3 facing the drive coil 2.

As shown in FIG. 3, the rotor yoke 4 is formed as a low-height flat cylindrical body with one side open.
It functions as a yoke of the drive magnet 3. The rotor yoke 4 is configured such that one end of a rotary shaft 5 is fixed to the center of the rotor yoke 4 and rotates with the rotary shaft 5.

As shown in FIG. 3, the rotary shaft 5 has a back surface 1 opposite to the main surface 1a to which the drive coil 2 of the substrate 1 is fixed.
It is rotatably supported by a bearing housing 8 fixed to b by a screw 7 or the like. The bearing housing 8 is provided with a bearing 9 for rotatably supporting the rotary shaft 5.

A thrust adjusting screw (not shown) for adjusting the distance between the driving coil 2 and the driving magnet 3 is provided at the lower end of the bearing housing 8. When the thrust adjusting screw is tightened, the rotor yoke 4 moves away from the substrate 1, and when it is loosened, the rotor yoke 4 moves toward the substrate 1.

The pulley 6 is attached to the tip of the rotary shaft 5 which penetrates through the top plate portion of the rotor yoke 4 and is fixed to the rotor yoke 4. This pulley 6
Are configured to rotate together with the rotor yoke 4.

In the capstan motor thus constructed, the thrust adjusting screw adjusts the facing distance between the drive coil 2 and the drive magnet 3 to a predetermined value.
When the predetermined value is reached, the rotor yoke 4 is rotated by the rotary shaft 5 supported by the bearing housing 8.

By the way, in this capstan motor,
A speed sensor for detecting the rotation speed of the motor is provided. The speed sensor includes an FG magnet 10 provided on the outer periphery of the rotor yoke 4, and a speed detection sensor 11 provided so as to face the FG magnet 10. This speed sensor detects the rotational speed of the motor by detecting the magnetic flux magnetized in the FG magnet 10 by the speed detection sensor 11.

The FG magnet 10 is composed of an annular ring magnet and is provided so as to surround the outer circumference of the rotor yoke 4. This FG magnet 1
0 is 360 in order to control the motor with high accuracy.
The NS is equally magnetized into equal to 720 equal parts.

On the other hand, the speed detecting sensor 11 is composed of a magnetic sensitive element such as a Hall element or an MR element which senses a magnetic flux. As shown in FIG. 4, the speed detection sensor 11 is held by a miniaturized holder 12 and fixed to a printed wiring board 13 prepared separately from the substrate 1. Lead wire 1 led out from the holder 12
As shown in FIG. 5, 4 is connected to the conductor pattern formed on the printed wiring board 13 by solder 15 by reflow.

The printed wiring board 13 is provided with a circuit sufficient to drive the motor. Further, as shown in FIG. 4, electronic components such as the IC chip 16 and the connector 17 are mounted on the printed wiring board 13 in addition to the speed detecting sensor 11. A Hall element 18 is formed on the printed wiring board 13 at a position facing the drive magnet 3.

Particularly, in the printed wiring board 13 in this embodiment, as shown in FIG. 4 and FIG. 5, the printed wiring board 13 is provided with an engaging portion which is a protrusion 19 formed on the substrate 1. It is locked by inserting the through hole 20 formed therein. The printed wiring board 13 is moved on the substrate 1 with the protrusion 19 as a fulcrum, so that the speed detecting sensor 11 fixed on the printed wiring board 13 is moved at a predetermined distance from the FG magnet 10. I have them to face each other.

As shown in FIG. 5, the protrusions 19 are formed on the side where the printed wiring board 13 is provided as cylindrical protrusions by half-cutting the substrate 1. The protrusion 19 and the speed detection sensor 11
As shown in FIG. 4, the positional relationship between and is such that the angle θ formed by the rotary shaft 5, the speed detecting sensor 11, and the protrusion 19 is 90 degrees. This angle θ is 90
By setting the degree, the speed detection sensor 11 is arranged in parallel to the FG magnet 10, and the arrangement accuracy of the speed detection sensor 11 with respect to the FG magnet 10 is increased.

The speed detecting sensor 11 is arranged to face the FG magnet 10 with a predetermined distance, as follows. First, as shown in FIG. 4, the through hole 20 provided in the printed wiring board 13 is inserted into and engaged with the protruding portion 19 of the substrate 1. Next, the printed wiring board 13 is moved on the substrate 1 in the arrow X direction in FIG. Then, when the facing distance between the speed detecting sensor 11 and the FG magnet 10 becomes a predetermined distance, for example, about 0.1 mm, the printed wiring board 13 is fixed to the substrate 1 with the screw 21.

As described above, when the printed wiring board 13 itself to which the speed detecting sensor 11 is fixed is moved on the substrate 1, as compared with the method of positioning and fixing the speed detecting sensor 11 directly on the substrate 1, The position accuracy of the speed detection sensor 11 with respect to the FG magnet 10 can be significantly improved, and the position adjustment can be easily performed. Further, since the speed detecting sensor 11 can be roughly fixed to the printed wiring board 13, the speed detecting sensor 11 can be mounted by an automatic machine and soldered by an automatic reflow furnace. Is possible.

In the above-mentioned embodiment, the protrusion 19 is formed by subjecting the substrate 1 to half blanking, but a columnar pin or the like is planted on the substrate 1 and the pin 19 is formed. Alternatively, the through hole 20 of the printed wiring board 13 may be inserted and engaged.

[0038]

As is apparent from the above description, according to the rotation detecting device of the present invention, the speed detecting sensor for detecting the rotation speed of the motor is mounted on the substrate instead of being provided on the substrate. Since the speed detecting sensor is fixed to the printed wiring board to be used, the speed detecting sensor can be roughly arranged on the printed wiring board to some extent, and the holder for holding the speed detecting sensor can be downsized. Further, by fixing the speed detecting sensor directly to the printed wiring board, the holder can be eliminated and the motor can be miniaturized.

On the other hand, according to the method of manufacturing the rotation detecting device of the present invention, the printed wiring board is locked to the engaging portion provided on the substrate, and the printed wiring board is placed on the substrate with the engaging portion serving as a fulcrum. By moving it, the speed detecting sensor provided on the printed wiring board is arranged to face the FG magnet with a predetermined distance.
The facing distance of the speed detection sensor with respect to the FG magnet can be easily adjusted. In addition, since the speed detection sensor can be roughly fixed to the printed wiring board to some extent, this speed detection sensor can be mounted by an automatic machine, and soldering can be performed by an automatic reflow furnace, which enables production. It can be expected to improve significantly.

[Brief description of drawings]

FIG. 1 is a plan view of a rotation detecting device to which the present invention is applied.

FIG. 2 is a bottom view of a rotation detection device to which the present invention has been applied.

FIG. 3 is a sectional view of a rotation detecting device to which the present invention is applied.

FIG. 4 is an enlarged plan view of an essential part of a rotation detection device to which the present invention is applied.

FIG. 5 is an enlarged cross-sectional view of a main part of a rotation detection device to which the present invention has been applied.

FIG. 6 is an enlarged cross-sectional view of a conventional rotation detection device.

FIG. 7 is an enlarged plan view of a conventional rotation detection device.

[Explanation of symbols]

 1 substrate 2 drive coil 3 drive magnet 4 rotor yoke 5 rotating shaft 10 FG magnet 11 speed detection sensor 12 holder 13 printed wiring board 19 protrusion 20 through hole

Claims (4)

[Claims] 1. A rotor yoke fixed to one end of a rotary shaft and provided with a drive magnet that rotates together with the rotary shaft, a drive coil fixed to a substrate facing the drive magnet, and an outer periphery of the rotor yoke. FG provided
In a rotation detection device for detecting the rotation speed of a motor including a magnet, a printed wiring board is locked to an engagement portion provided on a board,
By moving the printed wiring board on the board with the engaging portion as a fulcrum, the speed detection sensor provided on the printed wiring board is arranged to face the FG magnet with a predetermined distance. Characteristic rotation detection device. 2. The rotation detecting device according to claim 1, wherein the speed detecting sensor is directly fixed to the printed wiring board. 3. A rotor yoke fixed to one end of a rotary shaft and provided with a drive magnet that rotates together with the rotary shaft, a coil fixed to the substrate facing the drive magnet, and provided on the outer periphery of the rotor yoke. In a method of mounting a rotation detecting device for detecting a rotation speed of a motor, the printed wiring board is locked to an engaging portion provided on a board,
By moving the printed wiring board on the board using the engaging portion as a fulcrum, the speed detecting sensor provided on the printed wiring board is arranged to face the FG magnet with a predetermined distance. A method for mounting a rotation detecting device characterized by the above. 4. The method for mounting a rotation detecting device according to claim 2, wherein the speed detecting sensor is directly fixed to the printed wiring board.