JPH02174546A - Outer rotor motor - Google Patents

Abstract

PURPOSE:To thin an outer rotor motor by magnetizing a roller formed of a resilient magnet, for driving a load, fitted on the outer circumference of the rotor for the outer rotor motor with a predetermined pattern and making the roller correspond to the magnetic sensor for the stator. CONSTITUTION:A printed board 24 is adhered to a stator substrate 23 and a bearing 22 is fitted to a bearing housing 21 in the central section thus bearing the rotary shaft 28 of an outer rotor type rotor 31 rotatably. A cup-shaped rotor yoke 29 secured to the rotary shaft 28 is fixed with a permanent magnet 30 at the inner circumferential face thereof and secured to the housing 21 so that it rotates according to the stator 27. A roller 32 comprising a resilient magnet is fitted to the outer circumference of the rotor yoke 29 and power is transmitted to a load(not shown) through a section 32a projecting in the outer circumferential direction. The other projecting section 32b of the roller 32 is magnetized with a predetermined pattern thus making the roller correspond to a magnetic sensor 24a fixed to the printed board 24. By such arrangement, number of parts is reduced, the motor is thinned and mechanical or magnetic vibration is absorbed.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention is for driving a load such as a magnetic recording tape,
This invention relates to an outer rotor type motor that transmits the rotational force of a rotor to a load via a roller that rotates integrally with the rotor.

(Prior Art) Conventionally, the following outer rotor type motors have been used for driving magnetic recording tapes, for example. That is, in FIG. 6, 1 is a bearing housing provided with bearings 2, 2, 3 is a stator board attached to the flange portion 1a of this bearing housing, and a printed wiring board is mounted on the lower surface of the stator board 3. 4 is fixed.

5 is a stator core fixed to the bearing housing 1-;
A stator coil 6 is wound around this, and thus a stator 7
is configured. Reference numeral 8 denotes a rotating shaft supported by bearings 2, 2, and a rotor yoke 1o having a flat container shape is fixed to the lower end of this shaft through a boss portion 9.
An annular field magnet 11 facing the stator core 5 with a predetermined gap is fixed to the inner circumferential wall of the stator core 5, thereby forming a roller 12. 13 is rotor yoke 1
This is a ring-shaped frequency generator magnet fixed to the outer circumferential wall of 0, and is arranged to face a well-known frequency generator conductor button 14 formed on the printed wiring board 4. Reference numeral 15 denotes a capstan boss fitted to a portion protruding from the upper part of the rotating shaft 8, and an annular capstan rubber roller is fixed to the outer peripheral surface of the capstan boss, thereby forming a capstan roller 17 or 4+Xf. . And, although not shown, the cassette case containing the magnetic recording tape is ready! - When this happens, it comes into pressure contact with a tape drive tape roller or capstan roller 17 provided inside the cassette case.

Due to this configuration, a current is passed through the stator coil 6 of the stator 7 to rotate the rotor 12, and when the capstan roller 17 rotates via the rotating shaft 8, the capstan roller 17 is pressed against the capstan roller 17. Rotational force is transmitted to the tape roller by its thick friction force, thereby driving the magnetic recording tape. Also, the rotation speed of the frequency generator magnet 13 at this time is
and the frequency generator conductor pattern 14, and feedback is applied to the power supply for control.

(Problem to be solved by the invention) Generally speaking, in motors, as the rotor rotates, mechanical vibrations with the basic frequency of the rotor and electromagnetic vibrations transmitted to the rotor via the field magnet are generated. In many cases, this also generates noise. As the rotational speed of the rotor approaches its natural frequency, such vibrations cause resonance and become even louder, and the noise also becomes louder. In particular, in an outer rotor type motor like the conventional configuration mentioned above,
Because the rotor 12 is located outside the stator 7,
Noise generation due to the above-mentioned vibrations has been a major problem.

In addition, in the conventional configuration, the magnetic recording tape is driven by a capstan roller 17 with a claw above the rotating shaft 8, so there is a limit due to the height of the drive device itself or the height of the motor. However, there was a problem in that it was difficult to make it thinner.

The present invention has been made in view of the above circumstances, and its purpose is to reduce the vibration accompanying the rotation of the rotor and the noise generated thereby, and to reduce the brightness of the motor itself to provide a drive device. An object of the present invention is to provide an outer rotor type motor that can be made thinner.

[Structure of the Invention] (Means for Solving the Problems) The outer rotor type motor of the present invention has a '+74 structure so as to transmit the rotational force of the rotor to the machine via a roller that rotates integrally with the rotor. The present invention is directed to an outer rotor type motor equipped with a magnetic sensor for detecting a signal indicating the rotational state of the rotor, and the roller is formed of a magnet made of an elastic member, and the outer peripheral surface of the rotor is opposed to the magnetic sensor. The magnetic sensor is characterized in that the surface of the roller facing the magnetic sensor is magnetized in a predetermined pattern.

(Function) According to the outer rotor type motor of the present invention, the mechanical and magnetic vibrations generated by the rotation of the rotor are absorbed and attenuated by the roller made of magnets made of an elastic member disposed on the outer circumferential surface of the rotor. The natural frequency of the roller is also (
By setting =J, the occurrence of resonance can be avoided by shifting, the vibration of the rotor is reduced, and the generated noise is also reduced to a low level.

Further, since the rotational force of the rotor is transmitted to the load by the roller provided on the outer peripheral surface of the rotor, a capstan roller is not required.

Furthermore, the rotational state of the rotor is detected by the magnetic sensor using the part of the roller that is magnetized in a predetermined pattern.
There is no need to separately provide a magnet.

(Example) Hereinafter, the present invention will be explained using a magnetic recording tape. A first embodiment applied to a drive motor will be described with reference to FIGS. 1 and 2.

In FIG. 1 showing the overall configuration, 21 is a bearing 22.2.
2, a stator board 23 is attached to the flange portion 21a of the bearing housing 21, and a printed wiring board 24 is fixed to the lower surface of the stator board 23. 25 is the bearing housing 21
The stator core has a plurality of concentrically formed slots, each of which is wound with a stator coil 26, thereby forming a stator 27. Reference numeral 28 denotes a rotating shaft supported by bearings 22, 22, whose upper end is prevented from being removed by a stopper 28a, and on the other hand, a flat container-shaped rotor yoke is attached to its lower end via a boss 28b. 29 is fixed.

Reference numeral 30 denotes an annular field magnet fixed to the inner circumferential walls of the two rotor yoke, which faces the stator core 25 with a predetermined gap therebetween, thereby forming a rotor 31. 32 is attached to the outer peripheral wall of the rotor yoke 29.
The roller for transmitting rotational force is made of a rubber magnet made of an elastic member. This roller 32 is integrally formed with a band-shaped protruding portion 32a that protrudes in the outer circumferential direction, and the printed wiring board 24
A frequency generator magnet portion 32b magnetized in a predetermined pattern is formed in a portion facing the. Further, on the printed wiring board 24 side, a frequency generator conductor pattern 24a serving as a magnetic sensor is formed so as to face the rotation locus of the magnet portion 32b. 33 is pudding! - A Hall element attached to the wiring board 24, which is used to detect the rotational position of the rotor 31 based on the magnetic flux from the field magnet 30.

The drive motor 34, which is an outer rotor type motor configured as described above, is incorporated into a magnetic recording tape cassette drive device as shown in FIGS. 2(a) and 2(b).

That is, in FIGS. 2(a) and 2(b), the drive motor 3
4 is fixed to a base 35 so as to be above the rotor 31. Reference numeral 36 denotes a cassette in which a magnetic recording tape 37 serving as a load is stored, and this cassette has a tape roller 38 rotatably supported inside, and when the tape roller 38 is driven from the outside, the magnetic recording tape 37 is moved. Drive and run. When this cassette 36 is inserted into the insertion slot 39 from the direction of arrow A, the tape roller 3
8 is attached so as to be in pressure contact with the protruding portion 32a of the roller 32 of the drive motor 34.

According to the two-legged configuration, when the rotor 3 rotates due to current flowing through the stator coil 26, the rotational force is transmitted by frictional force to the tapered roller 38 that is in pressure contact with the rotor 38 via the stator coil 26. The recording tape 37 is driven. In this case, the mechanical and magnetic vibrations generated as the rotor 31 rotates are absorbed and attenuated by the roller 32 made of rubber magnets, and the natural frequency of the rotor 31 is shifted by the roller 32. This avoids resonance. As a result, the vibration of the roller 31 is reduced, and unlike the conventional roller, noise is reduced and a quiet and stable rotational state is obtained.

Further, according to this embodiment, the roller 32 is attached to the outer peripheral surface of the rotor 31 to directly drive the tape roller 38 of the cassette 36, so unlike the conventional case, there is no need to provide a capstan roller. Therefore, the height of the entire motor 34 can be reduced accordingly, and the entire drive device can therefore be made thinner.

Furthermore, according to this embodiment, since a predetermined magnetization pattern is formed on the roller 32 to form the frequency generator magnet part 32b, the number of parts can be reduced, and the product can be manufactured at low cost overall. .

The rotational speed of the rotor 31 is detected by the frequency generator magnet part 32b magnetized on the roller 32 and the frequency generator conductor pattern 24a of the printed wiring board 24 facing the magnet part 32b. This is performed by feedback control appropriate to the rotational speed of the rotor 31.

3 and 4 show a second embodiment of the invention. That is, in FIG. 3, 40 is a bearing housing equipped with bearings 41, 41, and 42 is a printed wiring board 42a.
43 is a stator consisting of a stator core 44 and a stator coil 45; 45 is a rotating shaft 46. The rotor consists of a rotor yoke 47 and a field magnet 48. Reference numeral 49 denotes a roller attached to the rotor yoke 47 so as to cover the outer peripheral surface and upper surface of the rotor yoke 47. Like the first embodiment, this roller is made of a rubber magnet made of an elastic material. A protrusion 49a for transmitting rotational force is provided on the part, and a frequency generator magnet part 49a is formed in a predetermined magnetization pattern on the part facing the printed wiring board 42a, and is formed on the printed wiring board 42a side. This is opposed to the frequency generator conductor pattern 42b.

The second embodiment also provides the same effects as the first embodiment, and since the roller 49 is configured to cover the upper surface of the rotor yaw 47, the vibration of the rotor 45 can be further reduced. Furthermore, there is no possibility that the roller 49 will fall off from the rotor yoke 47.

FIG. 5 shows a third embodiment of the present invention, which differs from the second embodiment in that a rotor yaw 50 in which a plurality of grooves 50a along the axial direction are formed on the outer peripheral surface in place of the rotor yoke 47 is used. In addition, in place of the roller 49, a roller 51 having protrusions 51a formed on the inner circumferential wall at positions corresponding to these grooves 50a is provided.

]] In this third embodiment, the same effects as in the second embodiment can be obtained, and the protrusion 51a of the roller 5 and the groove 50a of the rotor yoke 50 are engaged with each other, so that the roller 51 Since the rotor yoke 50 is fixed, there is no risk of the roller 51 slipping between the rotor yoke 50 and the rotational force of the rotor 45 can be reliably transmitted to the load.

[Effects of the Invention] As explained above, the outer rotor type motor of the present invention provides the following effects.

That is, since a roller made of an elastic magnet is placed on the outer peripheral surface of the rotor, the mechanical and magnetic vibrations generated as the rotor rotates are absorbed and attenuated, and the natural frequency of the rotor is reduced. It can be shifted to a value that does not resonate, and therefore, unlike the conventional method, noise caused by vibration can also be reduced.

In addition, the rollers are arranged on the outer peripheral surface of the rotor to transmit the rotational force of the rotor to the load.] Unlike the conventional method, there is no need to attach a capstan to the rotating shaft, and therefore the overall motor This allows the device to be made thinner, and the device into which the motor is incorporated can be made thinner.

Furthermore, the part of the roller that faces the magnetic sensor is magnetized in a predetermined pattern, and this detects the rotational state of the roller, which reduces the number of parts compared to conventional methods, resulting in lower costs overall. It can be manufactured.

[Brief explanation of the drawing]

1, 2(a) and 2(b) show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional side view, FIG. 2(a) is a top view showing an example of a usage state, and FIG. Figure 2 (b) is the same longitudinal sectional side view, 3rd
3 and 4 show a second embodiment of the present invention, FIG. 3 is a view corresponding to FIG. 1, FIG. 4 is a perspective view of the rotor portion, and FIG. 5 shows a third embodiment of the invention. An exploded perspective view of the rotor section shown;
FIG. 6 is a diagram corresponding to FIG. 1 showing a conventional example. In the drawing, 21, 4 (') is bearing nozzle, 23゜4
2 is the stator board, 24.42a is the printed wiring board, 24a and 42b are the frequency generator conductor patterns (magnetic sensors), 27.43 is the stator, 2846 is the rotating shaft, 29, 47.50 is the rotor yoke, 31 .45 is the rotor, 32, 49.51 is the roller, 34 is the drive motor (
36 is a cassette, 37 is a magnetic recording tape, and 38 is a tape roller.

Claims (1)

[Claims] 1. An outer rotor type that is configured to transmit the rotational force of a rotor to a load via a roller that rotates integrally with the rotor, and is equipped with a magnetic sensor for obtaining a signal indicating the rotational state of the rotor. In the motor, the roller is formed of a magnet made of an elastic member and is disposed on the outer peripheral surface of the rotor to face the magnetic sensor,
An outer rotor type motor characterized in that a surface of the roller facing the magnetic sensor is magnetized in a predetermined pattern.