JPS58207862A - Motor - Google Patents

Abstract

PURPOSE:To strengthen the rotary force of the second rotor as required by providing an electromagnet which releasably connects the first rotor to the second rotor which rotates individually from the first rotor. CONSTITUTION:When an electromagnet 13 is energized, a space magnetic flux is generated between collars 15a and 15b of a core 15. As a result, a rotor magnet 9b is rotated by the first rotor 9, a torque added with eddy current torque or hysteresis torque is produced at the second rotor 11, and a rotary torque of the same direction as the rotor magnet 9 is generated at the second rotor 11. The torque which is produced in this manner can be externally taken out by a pinion 12 which is integral with the second rotor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a first rotor that extracts synchronous rotational torque and a second rotor that extracts asynchronous rotational torque from a rotating magnetic field generated by a coil. It concerns electric motors.

Conventionally, when using an electric motor to drive a cassette tape recorder, for example, the capstan shaft was made to correspond to the output shaft of a synchronous motor to wind the tape, and a separate motor was installed on the 1μ axis to provide the drive source. Alternatively, the driving force was obtained from a synchronous motor via an idler or belt. However, the former example requires two or more electric motors. In addition, in the latter example, the number of rotations of the capstan shaft and the number of revolutions of the v - / l / shaft do not always have a constant proportional relationship, so a mechanical mechanism was required to stop the rotation of the reel shaft. .

However, these sliding mechanisms have a problem in that their characteristics change over time.

In view of the above points, this invention has been made to be suitable for this type of use, and although it uses one electric motor, it has two output shafts, and does not require a mechanical steering mechanism. Another object of the present invention is to provide an electric motor that stabilizes the drive characteristics of the reel shaft and can change the drive torque to the reel shaft as required. DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric motor according to an embodiment of the present invention will be explained below using the drawings.

1 to 4 are plan views of a cassette tape recorder as an example of a magnetic recording and reproducing device to which an embodiment of the present invention is applied, which provides the background of the present invention, and FIG. 1 shows the normal direction. Steady running (playback or recording) to (FP)
The state of time, Figure 2 is fast forwarding in the normal direction, ? (FF) state, Figure 3 shows steady running in the rewinding direction (playback or recording).
) (R,P,), and FIG. 4 shows the state of fast forwarding 5 (RW) in the rewinding direction. Also, the fifth
9 to 9 are drawings showing an electric motor according to an embodiment of the present invention, in which FIG. 5 is a longitudinal sectional side view thereof, FIG. 6 is a sectional view taken along the line Vl-VI in FIG. 5, and FIG. ■−■ in Figure 5
The line sectional view and FIG. 8 are side views of essential parts showing the capstan and idler portion of the device shown in FIGS. 1 to 4.

In Figures 5 to 8, the coil housing (3) of the electric motor (1) is integrally fixed to the board (2).
is made of an insulator such as plastic, and a bearing (4) is formed in the center, and the coil/L/(5) and magnetic flux detection element (6) are held integrally. A pulley (8) for transmitting rotational force to the capstan is integrally fixed to one end of the shaft (7), and this shaft (7) is fixed to the bearing (4). It is fitted so that it can rotate freely. A rotor disc (9a) having a rotor magnet (9b) is coaxially fixed to the pulley (8) to form a first rotor (9). Here, the rotor magnet (9b) has a mechanical angle of 45° as shown in FIG.
The rotor disc (9a) also serves as the magnetic circuit of the rotor magnet (9-D). (B) is the second rotor, which is disc-shaped and made of a material with eddy current characteristics such as an electromagnetic soft iron plate, or a material with hysteresis characteristics such as a hard magnetic material. (91
)) It also serves as a magnetic circuit for spatial magnetic flux. In other words, the second rotor (2) is fitted to rotate around the shaft (7), and the pinion (2) is integrally fitted to the second rotor (b). is fixed to. Therefore, an attractive force due to magnetic force acts between the rotor magnet (9) and the second rotor shaft, and this attractive force is applied to the end face (7a) of the stepped portion provided on the shaft (7). Frictional force is generated at the contact portion with the end surface of the second rotor (6).Therefore, the rotational force of the first rotor (9) contributes to the rotational force of the second rotor (6) via the frictional force. .

In the above configuration, the magnetic flux of the rotor magnet (9b) is detected by the magnetic flux detection element (6), and the control circuit (
If a drive current is supplied to the motor (not shown), it becomes a two-phase eight-pole synchronous motor and the first rotor (9) rotates. Therefore, the external synchronization signal and the first rotor (
The input of the carp yv (5) is controlled by comparing the control signal (detected by a known electromagnetic or optical method; the generation part is not shown) generated in response to the rotation of the carp yv (5). Then, the rotation of the first rotor (9) can be controlled to a desired rotation speed. In this way, synchronous rotational torque can be obtained at the rotor magnet (9b), that is, the pulley (8). Note that when it is necessary to reverse the rotation direction, it is possible to do so by a known method such as reversing the polarity of the magnetic flux detection element (6). Further, as described above, a magnetic circuit is configured by the spatial magnetic flux of the rotor magnet (9b) passing through the second rotor (6). When the rotor magnet (91)) rotates, the second rotor (6)
Eddy current torque or hysteresis torque,
Alternatively, the type of torque may differ depending on the material of the disk constituting the second rotor (b). ) is generated, and the rotor magnets) (
Rotational torque is generated in the same direction as the rotation in 9b). At the same time, the rotation from the first rotor (9) is caused by the frictional force generated at the part (7a) due to the suction force between the stepped part end face (7a) of the shaft (7) and the second rotor (B). A force is also added to the rotational torque of the second rotor. The resultant torque generated in the second rotor (b) in this way can be taken out to the outside by the pinion (2) that is integrated with the second rotor (2).

The greater the difference between the rotational speed of the shaft (7) (synchronous rotational speed) and the rotational speed of the second rotor (6), the greater the torque generated in the second rotor (6). FIG. 9 shows the relationship between the resultant torque generated in this way and the relative rotational speed (difference between the rotational speeds of the first rotor and the second rotor). (See figure)
The part indicates the torque component based on frictional force, and indicates that torque is generated regardless of the relative rotation speed. The part (to) is the component of the torque electromagnetically generated in the second rotor (2), and indicates that the generated torque increases in proportion to the relative rotational speed.

The torque that can be extracted from the second rotor (B) in this way is not utilized as rotational force in conventional electric motors due to electromagnetic and mechanical losses. However, since the rotational force obtained by the second rotor (B) can obtain almost constant torque regardless of the rotation speed, if it is used to drive the rotation of the reel, it will be possible to obtain a nearly constant torque. winding, l) Luk is obtained;
Stable long-life characteristics can be obtained without the need for a mechanical sliding mechanism.

In FIG. 5, (13 is an electromagnet, which is rotatably supported by a fixing pin α4 protruding from the substrate (2). That is, the electromagnet (l is a pair of flanges (3) Q51
)) with a bobbin-shaped core (to), and this core (
The carp μαQ wrapped around the core (to) and the core (to)
A metal bearing (b) coaxially fixed to is fitted into the fixed pin (to). The core (2) is made of a magnetically permeable material such as soft iron, and has a bobbin shape as shown in the figure. Therefore, if DC current is supplied to the coil αO to excite it, an N pole and an S pole will be magnetized on the inner surfaces of the pair of opposing disc-shaped collars (t5a) Q51), and a spatial magnetic flux will be created between them. configured. Parts of the first rotor (9) and second rotor (6) described above are sandwiched between such electromagnets (the shield is placed on a pair of flanges of the fur (2) Q51)). They are arranged in a superimposed manner at intervals with respect to these so that they are located in parallel. Therefore, in order to make this kind of arrangement relationship more practical, as shown in FIG. (3a) is formed.

The electromagnet (l) described above is electrically connected to the switch mechanism (to) shown in FIGS. 1 and 2, for example, by the slip mechanism (b) shown in FIG. In the above, the slip mechanism (b) consists of a slip ring Q7a) fixed to the outer surface of the flange of the core of the electromagnet (2), and a brush α7b) that is always in elastic contact with the slip ring Q7a). .

The brush α7b) is connected to the switch mechanism (to). In addition, in the switch mechanism (e) shown in FIGS. 1 to 4, ni) is a switch, Q81
)) is the power supply.

Next, a magnetic recording and reproducing apparatus employing the above-mentioned electric motor 41M (1) will be explained with reference to FIGS. 1 to 4 and FIG. 8.

In Figures 1 to 4, 2) is the normal direction capstan, cl! 51)) is a rewind direction capstan;
As best shown in FIG. 8, it is rotatably supported by a capstan bearing attached to the base plate (2),
It has a pulley part (b) for transmitting rotational force by a rubber belt (b). In Fig. 1, the shaft (7) of the electric motor (1) is mounted to rotate in the A direction, the pulley (8) also rotates synchronously in the A direction, and the rubber bellet (
A) is hung and the normal direction capstan (E)
The magnetic tape is rotated in the B direction, the magnetic tape () is sandwiched between the normal direction pinch roller (), and the magnetic tape () is run at a constant speed in the C direction. Note that the rewind direction pinch roller @b) is the rewind direction capstan (roller) in Fig. 1.
The pinion (6) is not pressed against the shaft (7).
), that is, in the A direction. (,(
1a) is a normal direction reel gear, and as shown in the cross-sectional view of FIG.
2a), and is configured to rotate freely by a fixed shaft (e) provided on the substrate (2). On the other hand, a rewinding reel gear 01b) is attached to a portion of the substrate (2) facing the normal direction reel gear 01a) with the same configuration. In other words, @
b) is the reel portion thereof, and 03b) is the fixed shaft.

Next, (E) is the idler gear and pinion (2)
, the normal direction reel gear 01a) and the rewinding direction reel gear (:11b) are arranged so as to transmit rotational force between them. In other words, the idler gear (goods) is the shaft (7
) is placed on an arm (not shown) so that the center of the reel gear (1a) and Return direction reel gear (:11
1)) is selectively engaged with and locked in one of the above-mentioned rotational directions, and transfers the rotational force of the pinion (2) to the reel gear (11a) or 1. ll'b), and in FIG. 1, the pinion) is rotating in the A direction. Therefore, the idler gear moves in the D direction.
The normal direction reel gear $1a) rotates in the E direction and winds the magnetic tape). In this case, due to the action of the electric motor (1) described above, winding can be performed with almost constant tension regardless of the rotation speed of the normal direction reel gear c (1a),
This makes it possible to obtain a magnetic tape running system with good performance.

FIG. 2 shows a state of rapid forwarding in the normal direction. At this time, it is necessary to transmit a strong rotational force to the reel portion of the normal direction reel gear (a).

So in this case, close the switch) and close the electromagnet (
By exciting Ll, the space magnetic flux generated between the flange Q5a)Qr,b) of the core (to) is transferred to the first rotor (9), the shaft (7) and the second rotor. (B)
Since a closed magnetic path is formed by the torque generated in the rotor magnet (9b) of the first rotor (Q) that is already rotating (in
) becomes larger than the torque of the second rotor (6). ) is transmitted to the second rotor via this electromagnet (2). In other words, on the flange α of the core (G)) 06b
) forms a magnetic circuit with the first rotor (9) and the second rotor (2), thereby creating an electromagnetic cup between the first rotor (9) and the electromagnet (13). It consists of a ring (transmission of force is performed using eddy current torque or hysteresis torque), and an electromagnet (
2) also rotates in the direction F in FIG. Similarly, an electromagnetic coupling is configured between the electromagnet (13) and the second rotor, and the torque of the first rotor (9) is combined with the torque of the second rotor (b). pinion (6),
Normal direction reel gear Cl1a) through idler gear ■
As a result, a strong torque is transmitted to the hub section of the audio cassette via the reel section, which generates a rotational force in the E direction, causing the magnetic tape to be fast-forwarded in the normal direction. will be shot. At this time, naturally, the normal direction capstan) and the normal direction pinch roller are not in contact with each other.

FIG. 3 shows a state of steady running (playback or recording) in the rewinding direction. At this time, the first rotor (9) and the second rotor (6) rotate in the H direction (opposite direction to FIGS. 1 and 2), so the rewinding direction capstan (rotation)
rotates in the machine direction, and the magnetic tape (a) is held by a pinch roller sail in the unwinding direction and runs at a constant speed in the J direction. Then, the pinion (6) that transmits the winding tension of the tape (C) also rotates in the H direction, and the idler gear
Reel gear that rotates in the crab direction and rewinds (, +lb)
rotates in the L direction and winds up the magnetic tape). In this case, the electromagnet (13) is deenergized.

As described above, according to this embodiment, the switching operation from steady running in the normal direction (state B in FIG. 1) to steady running in the rewinding direction (state in FIG. 3) is performed simply by using the electric motor (i). It is only necessary to reverse the direction of rotation of the cassette and at the same time selectively switch the pressing of the pinch rollers (e), (2) and b), so an automatic reversing audio cassette mechanism can be easily constructed.

Next, FIG. 4 shows a state of rapid forwarding (RW) in the rewinding direction. At this time, the first rotor (9) and the second
Since the rotor (6) rotates in the H direction and the electromagnet (to) is excited, the torque from the first rotor (9) is also transmitted to the rewind direction reel gear l:11b), and the winding is performed in the L direction. Sufficient rotational torque is supplied for the rewinding operation, and the rewinding operation is performed. In this case as well, switching from fast forwarding (the state shown in FIG. 2) to rewinding (the state shown in FIG. 4) requires only reversing the direction of rotation of the electric motor, and a simple mechanism can be realized.

As described above, according to the present invention, in the electric motor,
The rotation of a first rotor that generates synchronous rotational torque and the rotation of a second rotor that obtains driving force by the rotation of this first rotor and rotates independently from the first rotor can be freely engaged and disconnected. Since it is equipped with an electromagnet that is linked to the second rotor, if the rotational force extracted from the second rotor is insufficient only by the low torque rotational force generated by the second rotor, the first rotor is connected via the electromagnet. By transmitting the synchronous rotational torque from the rotor to the second rotor, there is an effect that the rotational force extracted from the second rotor can be strengthened as necessary.

[Brief explanation of drawings]

1 to 4 are plan views of a cassette tape recorder equipped with an electric motor according to an embodiment of the present invention.
The figure shows the steady running state in the normal direction, the second figure shows the fast forwarding υ state in the normal direction, the third figure shows the steady running state in the rewinding direction, and the fourth figure shows the steady running state in the rewinding direction.
The figures each show the state of fast forwarding in the rewinding direction, FIG. Figure 7 is the fifth
8 is a side view of the main parts showing the capstan and idler parts of the device shown in FIGS. 1 to 4, and FIG. 9 is a line diagram showing the characteristics of the electric motor. . (1)...i motion m, (3)...coil housing,
(5) Coil, (7) Shaft, (9) First rotor, (9a) Rotor disc, (9'b)
...Rotor magnet, (6)...Second rotor, (
13... Electromagnet, (g)... Core, ■:) Q5
1))...Coano collar, αQ...coil, α?
・Slip mechanism, Q7a)...Slip ring, α7
b)...Brush, (Foundation)...Nuitch mechanism. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - (1 other person) Geki 5;
〆7 6th γ / (Figure 7 v, 8w 9th ward--ba, r'I.

Claims (3)

[Claims] (1) A rotatable first rotor comprising a coil that generates a rotating magnetic field and a magnet facing the coil; a rotational driving force is obtained from the first rotor; A second rotor that can be rotated individually, an electromagnet that is arranged in an overlapping manner with respect to the first rotor and the second rotor, and a twitch mechanism for exciting and demagnetizing the electromagnet, and the electromagnet can be rotated. An electric motor characterized in that the electromagnet and the twitch mechanism are electrically connected to each other by a slip mechanism. (2) A patent claim in which the electromagnet is composed of a coil coaxially supported on its rotating shaft and a core having a pair of disk-shaped flanges, and that different types occur in the pair of flanges. The electric motor according to item 1 in the scope of . (3) The electric motor according to claim 2, wherein the slip mechanism includes a slip ring provided on the collar and an elastic brush that is constantly in contact with the slip ring.