JPS6315647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a linear tracking type record player.

In a linear tracking type record player, the tone arm is rotated by the spiral sound groove of the record while the record is being played, and is angularly displaced with respect to the tangential direction of the record. When this deviation angle exceeds a predetermined value, the tone arm is moved linearly so as to make this deviation angle zero. Since the rotation and linear movement of the tone arm are repeated alternately, the tone arm ends up performing an inchworm movement in the angular direction. The linear movement is performed by, for example, a linear motor. In other words, when the deviation angle of the tone arm with respect to the tangential direction of the record is detected by the deviation angle detector, the linear motor is driven based on the detection output of this detector, and the horizontal rotation axis of the tone arm is controlled via the carriage. (the horizontal rotating shaft that rotatably supports the tone arm in a horizontal direction substantially parallel to the record) is moved in the radial direction of the record. Therefore, this type of record player must be equipped with means for detecting the deflection angle of the tone arm.

As a conventional deviation angle detection means, for example,
One example is the one proposed by the applicant of the present invention in No. 54-79351 (see Japanese Patent Publication No. 60-59656). In this case, a shutter is attached to the lower end of the horizontal rotation axis of the tone arm via a holding plate, and a pair of light receiving elements is fixedly arranged above the shutter, and a light emitting element is fixedly arranged below it. . Therefore, when the tone arm rotates, the shutter moves in the circumferential direction of the horizontal rotation axis and is displaced relative to the pair of light receiving element and light emitting element. This causes a change in the amount of light received by the pair of light receiving elements. This change in the light receiving element is extracted as a detection output, and the deviation angle of the tone arm is detected.

However, such a deviation angle detection device requires a large number of parts and requires a relatively large space to install the device. Additionally, this device must be mounted on the underside of the tone arm supporting carriage, at the lower end of a horizontal axis of rotation extending downwardly through the carriage. Therefore, after assembling the tone arm assembly, it is necessary to assemble the deflection angle detecting device from below the carriage, resulting in a disadvantage that assembly becomes troublesome.

It is an object of the present invention to overcome these problems, and the present invention aims at overcoming the above-mentioned problems. and a carriage supporting the tone arm, and a step that performs linear tracking control of the tone arm so that the tone arm moves linearly in a direction perpendicular to the tangential direction of the record by moving the carriage linearly. A motor 1 is disposed coaxially with the rotary shaft so as to move linearly together with the carriage, and by rotationally driving the rotary shaft, the tone arm is moved substantially parallel to the record disc. and a second motor for controlling rotation in the direction by motional feedback,
The second motor includes a magnet constituting a stator or a rotor, a coil arranged on the rotor side or the stator side with a predetermined distance from the magnet, and a coil arranged at a predetermined distance from the magnet. and a magnetically sensitive element disposed on the rotor side or the stator side, respectively, and when the tone arm is not angularly displaced with respect to the tangential direction of the record, the magnetically sensitive element is located at the boundary of magnetization of the magnet. By selecting a positional relationship of the magnetically sensitive element with respect to the magnet such that the magnetically sensitive element faces the magnet, the magnetically sensitive element detects an angle of deviation of the tone arm with respect to a tangential direction of the record. , supplying a detection output from the magnetically sensitive element to a drive coil of the first motor,
The present invention relates to a record player characterized in that the first motor is configured to perform linear tracking control of the tone arm.
Therefore, the deflection angle detector can be simply constructed and easily assembled.

The invention will now be explained with reference to the illustrated embodiments.

FIG. 1 is a plan view of this record player, and a large circular opening 2 is formed in the upper plate 1 of the cabinet of this player.
A turntable 3 is arranged. The turntable 3 is rotatably supported by a spindle 4 and is configured to be rotationally driven by a motor (not shown). Furthermore, a tone arm 5 is arranged on the upper plate 1 of the cabinet.
This tone arm 5 is fixed to a rectangular parallelepiped case 6. And this case 6 is the horizontal rotation axis 7
Moreover, this horizontal rotation shaft 7 is configured to move linearly from side to side in FIG. Therefore, the tone arm 5 moves over the record 8 on the turntable 3.
It is configured to move while maintaining an attitude approximately tangential to the sound groove. For this reason, the record stylus of the cartridge 9 attached to the tip of the tone arm 5 linearly tracks the record 8. The tone arm 5 is divided into two parts by the case 6, and the tone arm 5 is fixed to the front side of the case 6. An extension 10 of the tone arm 5 is fixed to the back side of the case 6. A counterweight 11 is attached to this extension portion 10.

Next, the mechanism for linearly driving the tone arm 5 will be explained with reference to FIGS. 2 to 4. The vertically disposed horizontal rotation shaft 7 passes through the sleeve 12 as shown in FIG. At the same time, it is rotatably supported by this sleeve 12 by a pair of upper and lower bearings 13. The sleeve 12 is inserted into a through hole 16 of a boss 15 formed integrally with the carriage 14. This sleeve 12 is fixed to the sleeve 12 by a set screw 17 (see FIG. 4). Therefore, by loosening this set screw 17, the sleeve 12 can be moved in the height direction, thereby adjusting the height of the tone arm 5.

A carriage 14 supporting the horizontal rotating shaft 7 is supported by a pair of rails 18 and 19 so as to be movable in the longitudinal direction thereof. That is, a pair of support plates 20 and one support block 21 are attached to the lower surface of the carriage 14. The pair of support plates 20 are arranged apart from each other in the length direction of the rail 18, and each of these support plates 20 holds a slide bearing 22,
These bearings 22 are fitted to the rail 18. In addition, the support block 21 has a groove 23.
is formed, and the rail 19 is received in this groove 23. And this rail 1
The roller 24 is attached to the support shaft 25 so as to be in contact with the upper surface of the support shaft 9.
It is supported on the support block 21 by. Therefore, the carriage 14 is mounted on the pair of rails 18, 1 by the pair of slide bearings 22 and the rollers 24.
It is now supported by three points at 9. As shown in FIG. 2, the pair of rails 18 and 19 are held at both longitudinal ends by U-shaped holding plates 26 and 27.

A linear motor 28 is disposed below the rail 18 in parallel with the rail 18, as shown in FIG. This linear motor 28 is composed of a pair of magnets 29 that are arranged in parallel and facing each other, and a coil 30 that is arranged between these magnets 29. The magnet 29 is held by the holding plates 26 and 27 via a mounting plate 31 which also serves as a yoke. Further, the coil 30 is wound around a bobbin 32. A projecting piece 33 that projects upward is integrally formed on the bobbin 32, and the coil 30 is connected to the support plate 20 by this projecting piece 33. Furthermore, a through hole 34 is formed in the center of this bobbin 32;
A yoke 35 passes through 4. This yoke 35
Both ends of are also held by the holding plates 26 and 27. Therefore, when current flows through the coil 30, the coil 30 receives a force in the longitudinal direction of the rail 18, and this force also acts on the protruding piece 33 of the bobbin 32 and the support plate 2.
0 to the carriage 14, thereby causing the carriage 14 to move along the rails 18, 19.

A linear movement detector 36 is disposed below the rail 19. This detector 36 consists of a single magnet 37 and a coil 38. And the magnet 37 is a mounting plate 39 which also serves as a yoke.
(See FIG. 2). The coil 38 is wound around a bobbin 40 as shown in FIG. 3, and a protruding piece 41 of the bobbin 40 is attached to the support block 21. Further, a yoke 43 is disposed passing through the through hole 42 of the bobbin 40, and both ends of the yoke 43 are held by the holding plates 26 and 27. Therefore, when the carriage 14 moves, the coil 38 also moves, and at this time, a current flows through the coil 38 because it interlinks with the magnetic flux formed by the magnet 37.

In this way, the linear motor 28 and the linear movement detector 36 are arranged below the rails 18 and 19, respectively, and since the motor 28 and the detector 36 are arranged apart from each other, the detector 36 is not affected by leakage magnetic flux of the magnet 29 of the motor 28, and noise of the linear motor 28 is not detected. Therefore, when motional feedback of the motor 28 is performed by the detector 36 as described later, the horizontal linear movement of the tone arm 5 can be performed very smoothly.

Next, the mechanism for driving and detecting the vertical rotation of the tone arm 5 for raising and lowering the tone arm 5 will be described. The upper end of the horizontal rotation shaft 7 has an inverted U-shaped cross section as shown in FIG. It is fixed to the bottom of the connecting plate 44. A vertical rotating shaft 45 arranged horizontally is attached to the upwardly extending portion of the connecting plate 44.
Both ends thereof pass through the side wall of the case 6. As a result, the case 6 and the tone arm 5 fixed to the case 6 are rotatably supported by the horizontal rotation shaft 7 via the vertical rotation shaft 45. The rotation of the tone arm 5 about the shaft 45 causes the record stylus of the cartridge 9 to come into contact with or separate from the record 8.

As shown in FIG. 3, inside the case 6, a vertical rotation drive motor 46 and a vertical rotation detector 47 are arranged. The motor 46 is arranged on the tip side of the tone arm 5 with respect to the axis of the horizontal rotation shaft 7. This motor 46 is connected to a pair of magnets 4.
8 (see FIG. 2), and a coil 49 disposed between these magnets 48. 1
The pair of magnets 48 are respectively fixed to the inner sides of opposite side walls of the case 6. Therefore, the side wall of this case 6 also serves as a yoke. Also coil 4
9 is wound around the outer circumference of a rectangular cylindrical bobbin 50, and the bobbin 50 is fixed to the connecting plate 44. And the through hole 5 in the center of this bobbin 50
A yoke 52 is inserted into the housing 1 and extends vertically. The yoke 52 is fixed to the bottom of the case 6, and its upper end is in contact with the lid 53 of the case 6.

The vertical rotation detector 47 also has the same configuration as the vertical rotation drive motor 46. That is,
A pair of magnets 54 of this detector 47 are fixed to the inside of the side wall of the case 6 so as to face each other. A coil 56 wound around a bobbin 55 is arranged between these magnets 54. The bobbin 55 wound with the coil 56 is fixed to the connecting plate 44. And the through hole 57 of the bobbin 55
A yoke 58 passing vertically through the case 6 is fixed to the bottom of the case 6, and the upper end of the yoke 58 is in contact with the lid 53. Therefore, when current is applied to the coil 49 of the motor 46, the magnet 48 receives a force, causing the case 6 and the tone arm 5 to rotate about the vertical rotation axis 45. Along with this rotation, a current flows through the coil 56 of the detector 47, and the vertical rotation of the tone arm 5 is detected. By feeding back the detection output of the detector 47 to the motor 46, vibrations when the tone arm 5 is raised or lowered are prevented.

Next, the flat motor 60 disposed coaxially with the horizontal rotating shaft 7 will be described. This motor 60 is a motor for controlling the rotation of the tone arm 5 around the horizontal rotation axis 7, and includes a detection coil for controlling the rotation speed of the tone arm 5, and a detection coil for controlling the rotation speed of the tone arm 5, and a detection coil for controlling the rotation speed of the tone arm 5, and a detection coil for controlling the rotation speed of the tone arm 5. and a deflection angle detector for detecting the deflection angle of 5.
That is, as shown in FIGS. 3 and 4, the stator yoke 61 is fixedly attached to the upper end of the sleeve 12. As shown in FIGS. And this yoke 6
A magnet 62 is fixedly attached to the top surface of 1. The magnet 62 has a flat ring shape, and is magnetized alternately in the circumferential direction to have multiple poles, for example eight poles, as shown in FIG.

A group of coils is arranged above the magnet 62, as shown in FIGS. 3 and 4, facing the magnet 62. These coil groups constitute the rotor of the motor 60.
For example, six coils 63, 64, 65, 66, 6
7, 68, and a coil 69 for detecting the rotational speed of the motor 60. These coils 63 to 69 are each connected to a flat fan-shaped bobbin 7.
0, and these bobbins 70
is fixed to the lower surface of the rotor yoke 71. The rotor yoke 71 is fixed to the horizontal rotating shaft 7 at a stepped portion 72 of the horizontal rotating shaft 7 .

As shown in FIG. 5, the coils 63 to 68 of the motor 60 are arranged so as to straddle the N and S poles at the boundaries between the six magnetizations of the eight-pole magnet 62. Further, the speed detection coil 69 is disposed at one of the remaining two magnetized boundary portions of the magnet 62 so as to straddle the N pole and the S pole. Furthermore, a magnetically sensitive element 73 is arranged to straddle the north and south poles of the magnet 62 at the remaining one magnetization boundary. This magnetically sensitive element 73 constitutes a deflection angle detector of the tone arm 5, and when the tone arm 5 is angularly deflected with respect to the tangential direction of the record 8, it is proportional to this deflection angle. It is designed to generate a signal with the same output. Note that this magnetically sensitive element 73 is also fixed to the lower surface of the rotor yoke 71.

As mentioned above, in this record player,
A motor 60 which is flat in the axial direction is disposed coaxially around the outer circumference of the horizontal rotating shaft 7, and a coil 69 for detecting the rotation speed of the tone arm 5 and a coil 69 for detecting the rotation speed of the tone arm 5 are installed in the motor 60. Since the angle detector 73 is incorporated, the space in the axial direction of the horizontal rotation shaft 7 is particularly small even though the motor 60 is disposed above the carriage 14, and the turning drive device of the tone arm 5 is can be configured compactly. Further, as will be described later, the tone arm 5 performs linear tracking while performing an inchworm movement in the angular direction while rotating by a minute angle (about several degrees at most) about the horizontal rotation axis 7. Therefore, the rotation angle of the motor 60 may be small, and the magnet 62 can be magnetized to a large number of poles in the circumferential direction, and a large number of coils 63 to 63 can be magnetized in the circumferential direction.
68 can be provided. Therefore, coil 6
It is possible to obtain a driving force corresponding to the number of motors 3 to 68, and it is possible to reduce the radius of the motor 60. Therefore, the motor 60 can be operated not only in the axial direction, but also in the axial direction.
It can also be configured compactly in the radial direction.

Further, in this motor 60, the drive coil 6
3 to 68 and the speed detection coil 69 of the same standard can be used in common. Furthermore, the driving magnet, the speed detection magnet, and the deflection angle detection magnet are all constituted by a common magnet 62. Therefore, the number of parts is reduced as well as the types of parts are reduced.
Furthermore, the swing drive device for the tone arm 5 can be constructed at low cost.

Further, in this record player, the tone arm 5 is attached to the case 6 in which the vertical rotation drive motor 46 and the vertical rotation speed detector 47 are incorporated.
Furthermore, this case 6 is attached to the upper end of the horizontal rotating shaft 7. Next, a swing drive motor 60 is attached to the outer circumference of the horizontal rotating shaft 7, and the horizontal rotating shaft 7 is fitted into the sleeve 12 to be supported. Then, this sleeve 12 is attached to the boss 1 of the carriage 14.
The tone arm 5 is mounted on the carriage 14 by fitting into the through hole 16 of the tone arm 5 and fixing it with a set screw 17. That is, after the vertical rotary drive section and the swing drive section are assembled as one assembly in advance, the carriage 14 can be attached to this assembly, and there is no need to attach parts to the horizontal rotation shaft 7 from the underside of the carriage 14. This facilitates assembly work.

The assembly mounted on the carriage 14 can also be assembled by loosening the setscrew 17.
The height can be freely adjusted by moving the sleeve 12 vertically relative to the boss 15 of the carriage 14. Therefore, the height of the tone arm 5 can be easily adjusted. Furthermore, the center of gravity of the assembly supported by the carriage 14 is located between the pair of rails 18 and 19, and in addition, in a plan view as shown in FIG. Since it is arranged inside the triangle thus formed, the horizontal movement of the carriage 14 is very stable, and no unnatural force is applied to the rails 18, 19.

Further, in this record player, the motor 60 is structurally capable of rotating 360 degrees if the lead wires of the coils 63 to 69 are long. That is, the rotor coils 63 to 68 can be rotated 360 degrees with respect to the stator magnet 62 fixed to the sleeve 12. Therefore, when transporting or storing this record player, the first
As shown by the two-dot chain line in the figure, the tone arm 5 can be stored parallel to the rails 18 and 19, that is, rotated 90 degrees around the horizontal rotation axis 7 relative to the state in use. can. Therefore, the tone arm 5 can be held safely and reliably when not in use.

Further, in this record player, the deflection angle detector of the tone arm 5 is composed of a magnetically sensitive element 73 fixed to a rotor yoke 71, and this magnetically sensitive element 73 also serves as the stator of the motor 60. When the tone arm 5 is angularly deviated relative to the magnet 62, the angular deviation of the tone arm 5 is thereby detected. Therefore, the deflection angle detector 73 is very small and does not require space. Furthermore, since the number of parts is small and the structure is simple, assembly is easy. Furthermore, since the cost of the deflection angle detector 73 is also reduced, the record player can be provided at a low cost.

Note that in the motor 60, the magnet 6
2 constitutes a stator, and coils 63 to 68 constitute a rotor, but by reversing these, coil 6
3 to 68 on the fixed side, and magnet 6
2 may be on the movable side. In this way, the lead wires of the coils 63 to 69 can be easily processed.
In this case, the relationship between the deflection angle detector 73 and the magnet 62 is naturally reversed, and the deflection angle detector 73 is fixedly arranged with respect to the rotor magnet 62.

Next, the operation of this record player with the above configuration will be explained using automatic performance as an example.

The automatic performance operation is started from a state where the tone arm 5 is at the armrest position as shown by the dashed line in FIG. When the linear motor 28 is driven by an operation means (not shown) or an instruction from the system controller, the tone arm 5
is moved straight to the left in FIG. That is, in FIGS. 2 and 3, when current is supplied to the coil 30, the carriage 14 is moved along the rails 18, 19 by the driving force of the linear motor 28. Furthermore, since the tone arm 5 is supported by the carriage 14 via the sleeve 12, the horizontal rotating shaft 7, and the case 6, the tone arm 5 is linearly moved in a direction perpendicular to its length.

Moreover, since the linear motor 28 is under motion feedback control by a linear movement detector 36 (see FIGS. 2 and 3), linear movement is performed smoothly. That is, as shown in FIG. 6, the voltage of the detection output generated in the coil 38 of the linear movement detector 36 is supplied to one input terminal of the operational amplifier 88. The other input terminal of this operational amplifier 88 is connected to the coil 30 of the linear motor 28.
Because the voltage applied to the amplifier 88 is fed back, the two input voltages are compared. Depending on whether the output of the amplifier 88 is positive or negative, either the transistors 89 or 90 is selectively activated.
ON, and as a result, current flows through the drive coil 30 in the forward or reverse direction, and the linear motor 28
generates a driving force such that the output of the speed detection coil 38 becomes zero. Furthermore, when the tone arm 5 is moved horizontally by the linear motor 28 as described above, a DC bias voltage is actually applied to the one input terminal of the operational amplifier 88 in a manner that is superimposed on the detection output of the coil 38. In this state, the above-mentioned motional feedback control is performed. This allows the tone arm to move linearly very smoothly.

As the tone arm 5 moves, the cartridge 9
When the record stylus reaches the top of the sound groove on the outermost circumference of the record 8, this is detected by a record size detection means (not shown), and no DC bias voltage is applied to the input of the operational amplifier 88. When the linear motor 28 stops driving, the tone arm 5 moves downward. That is, the vertical rotation drive motor 4 shown in FIGS. 2 and 3
Electric current is supplied to the coil 49 of motor 4.
6 is driven. Accordingly, the case 6 supporting the magnet 48 and yoke 52 of the motor 46 rotates counterclockwise in FIG. 3 about the vertical rotation shaft 45. Along with this, the tone arm 5 fixed to the case 6 is also rotated in the same direction, and the record stylus at the tip of the arm 5 comes into contact with the record disc 8, and the record performance is started. Moreover, when the tone arm 5 vertically rotates, it is subjected to motional feedback control such that the detection output of the speed detection coil 56 of the vertical rotation detector 47 is always constant by the circuit shown in FIG. Furthermore, vertical rotation of the tone arm 5 is also performed very smoothly. Note that this circuit is also the 6th circuit.
The configuration is almost the same as the drive circuit for the linear motor 28 shown in the figure. That is, as shown in FIG. 7, there is an operational amplifier 91 that compares the voltage applied to the coil 49 of the motor 46 and the output voltage of the detection coil 56, and a pair of operational amplifiers that are selectively turned on by the output of the operational amplifier 91. Transistors 92, 93
It is composed of. When the tone arm 5 is vertically rotated, the coil 5 of the detector 47
A DC bias voltage is superimposed on the output of the motor 6 and supplied to the operational amplifier 91, so that a constant driving force is obtained from the motor 46.

Next, we will discuss the operation of the tone arm 5 while playing a record.Since the tone groove of the record 8 is formed in a spiral shape toward the center, the record needle moves toward the record 8 as the record 8 rotates. gradually move toward the center of For this reason, the tone arm 5 rotates clockwise about the horizontal rotation shaft 7, albeit at a small angle in FIG. Then, the rotor yoke 71 of the motor 60, which is connected to the tone arm 5 via the case 6 and the horizontal rotating shaft 7, also rotates in the same direction. Therefore, the magnetically sensitive element 73 fixed to the rotor yoke 71 moves relative to the magnet 62 in the circumferential direction of the magnet 62. For this reason, the magnetically sensitive element 73 is deviated from the boundary between the N and S poles of the magnet 62. As a result, the magnetically sensitive element 73 generates an output corresponding to the amount of deviation with respect to the magnet 62. This detection output is the sixth
As shown in the figure, it is supplied to a comparison input terminal of an operational amplifier 94. Therefore, an output corresponding to the deflection angle of the tone arm 5 is extracted from the operational amplifier 94. The output of this operational amplifier 94 is supplied to the one input side of the operational amplifier 88. That is, since a bias voltage is applied to one input terminal of the operational amplifier 88, the linear motor 28 is driven by this. Then, the tone arm 5 is moved toward the center of the record 8 by the linear motor 28 via the carriage 14. In other words, in this record player, the tone arm 5 is connected to the record 8.
When the angular deviation occurs due to the rotation of the tone arm 5, this is detected by the magnetically sensitive element 73, and upon this detection, the linear motor 28 moves the carriage 14 so as to eliminate the angular deviation of the tone arm 5. That is, in this record player, the tone arm 5 moves in an angular direction like an inchworm.

Furthermore, in this record player, a bias voltage corresponding to the deflection angle of the tone arm 5 is applied to the above-mentioned one input terminal of the operational amplifier 88 of the drive circuit of the linear motor 28 so as to be superimposed on the output of the coil 38. Therefore, the compensation of the deflection angle of the tone arm 5 becomes very smooth. That is, since the drive of the linear motor 28 that compensates for the deflection angle of the tone arm 5 receives motional feedback as the coil 38 is detected, the deflection angle error is very small, and the inchworm movement in the above-mentioned angular direction is minimized. The process is done finely and smoothly. Furthermore, since the drive circuit for compensation of the deflection angle and this motional feedback circuit are also used as those for the linear drive, the structure becomes very simple.

Furthermore, in this record player, the horizontal rotation of the tone arm 5 is also explained in FIGS.
Motional feedback control is performed by a horizontal rotation drive motor 60 and a horizontal rotation detector 69 shown in the figure, thereby suppressing the rotational vibration of the tone arm 5 in the horizontal direction and reducing the above-mentioned deviation. Position angle detection is performed stably. That is, especially in a tone arm in which the stylus pressure of the record stylus is applied by the counterweight 11, the center of gravity of the tone arm 5 does not coincide with the axis of the horizontal rotation shaft 7, and as shown at 95 in FIG. It is biased toward the tip of arm 5. Due to this deviation of the center of gravity, when the tone arm 5 moves horizontally, the tone arm 5 receives a force that causes it to be swung around. In other words, rotation about the center of gravity 95 occurs. Therefore, something other than the actual amount of deviation is added and detected, making the horizontal feed very unstable.

Therefore, as shown in FIG. 8, the detection coil 6
The operational amplifier 96 compares the detection output of 9 and the voltage applied to the coils 63 to 68 of the horizontal rotation drive motor 60.
One of the two transistors 97 and 98 is selectively driven. As a result, a current in the forward or reverse direction flows through the drive coil 63, and the motor 60 generates a driving force such that the output of the detection coil 69 becomes zero. This force brakes the rotation of the tone arm 5 about the horizontal rotation axis 7, which eliminates the wobbling of the tone arm 5 that performs linear tracking, and allows for highly accurate linear displacement in the horizontal direction. And it will be done smoothly.

Furthermore, by performing motional feedback on the horizontal rotation of the tone arm 5, the low frequency resonance of the tone arm 5 is significantly reduced.
Furthermore, crosstalk is also improved. That is, the first
As shown in Figure 0A, if motional feedback in the horizontal rotation direction is not performed, a peak will appear in the cartridge output at the low resonance frequency o, and crosstalk will occur in the left and right channels during stereo performance. A peak appears. However, when horizontal rotation motion feedback control is performed, the output of the cartridge becomes flat at the low resonant frequency, as shown in Figure 10B.
Crosstalk is also improved.

Note that the circuit shown in FIG. 8 is a circuit in which drive coils 63 to 68 of the motor 60 are connected in parallel with each other, and these coils 63 to 68 are connected to the magnet 62 which is magnetized into eight poles in the circumferential direction. It is placed at the boundary of magnetization. Therefore, these coils 63 to 68
The direction of the magnetic flux received by the coils is alternately opposite, so if the coils 63 to 68 are simply connected in parallel, torques in alternately opposite directions will be generated, and these will cancel each other out to obtain driving force. I won't be able to do it. Therefore, the connection direction is alternately reversed. That is, the inner and outer terminals of the coils 63 to 68 are
a, 63b, 64a, 64b...68a, 68b
Then, the terminals 63a, 64b, 65a, 66
b, 67a, 68b are connected to the emitters of transistors 97, 98, and the other terminals 63b, 6
4a, 65b, 66a, 67b, and 68a are grounded. When the coils 63 to 68 of the motor 60 are connected in parallel with each other in this way, the coil 63
~68 resistance becomes small, and a large driving force is obtained. Also, one of the coils 63 to 68
The reliability is high because driving force can be obtained even if a wire breakage occurs. Further, the coils 63 to 68 can be wound many times using thin wire.

Note that the coils 63 to 68 of this motor 60 may be connected in series as shown in FIG.
Also in this case, these coils 63 to 68
The terminals of these coils 63 to 68 are alternately connected so that the electromagnetic force obtained by the coils generates torque in the same direction. If the coils 63 to 68 are connected in series, the number of turns can be reduced.

As described above, in this record player, the rotational movement of the tone arm 5 is controlled by motional feedback.
The record needle performs linear tracking. As the record is played, the tone arm 5 moves toward the center of the record 8 in the length direction of the rails 18 and 19. When the record stylus moves to the final groove position of the record disc 8 and the record playing ends, as indicated by the dotted line in FIG. 1, this is detected by a sensor not shown. Upon detection by this sensor, the vertical rotation drive motor 46 is driven again, and the tone arm 5 is moved up. Thereafter, the tone arm 5 is further driven by the linear motor 28 to the right armrest position (indicated by a chain line) in FIG. As a result, the tone arm 5 is held at the armrest position and is ready for the next record performance.

As described above, the present invention is directed to the magnetization boundary of the magnet that is disposed coaxially with the rotation axis of the tone arm and that constitutes the stator or rotor of the motor that controls the rotation movement of the tone arm by motional feedback. A magnetically sensitive element is disposed opposite the section, and the magnetically sensitive element detects the angle of deviation of the tone arm with respect to the tangential direction of the record. Therefore, the detected portion can also serve as the magnet of the motor, and it is sufficient to simply provide a magnetically sensitive element as the deflection angle detecting means.
Therefore, since the number of parts is small and the magnetically sensitive element is very small, no particular space is required for detecting the deflection angle. Furthermore, since this magnetically sensitive element only needs to be attached to the rotor or stator in opposition to the magnet, assembly is very simple, and an inexpensive record player can be provided.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention,
FIG. 1 is a plan view of the record player of this embodiment, FIG. 2 is a perspective view of the main parts of the tone arm drive mechanism, and FIG. 3 is a vertical sectional view taken along the line - in FIG.
Figure 4 is a vertical sectional view taken along the - line in Figure 2;
The figures are a view taken along the - line in Fig. 3 showing the plane of the swing drive motor, Fig. 6 is a circuit diagram of a motional feedback circuit for linear drive of the tone arm, and Fig. 7 is a view of the vertical rotation of the tone arm. Figure 8 is a circuit diagram of a motional feedback circuit for driving the tone arm in rotation, and Figure 9 is a modification of the motional feedback circuit for driving the tone arm in rotation. In the circuit diagram, FIG. 10A is a graph of the low frequency resonance characteristic of a conventional record player, and FIG. 10B is a graph of the low frequency resonance characteristic of the record player of this embodiment. In addition, in the symbols used in the drawings, 5...Tone arm, 7...Horizontal rotation axis (swivel axis), 14...
Carriage, 28... Linear motor (first motor), 60... Flat motor (second motor), 62
. . . Magnet, 73 . . . Magnetically sensitive element.

Claims (1)

[Scope of Claims] 1. A carriage that supports the tone arm via a pivot shaft that rotatably supports the tone arm in a direction substantially parallel to the record;
By moving the carriage in a straight line,
a first motor that performs linear tracking control of the tone arm so that the tone arm moves linearly in a direction perpendicular to the tangential direction of the record; and a rotating motor that moves the tone arm linearly in unison with the carriage. and a second motor disposed coaxially with the shaft and controlling the rotation of the tone arm in a direction substantially parallel to the record disc by driving the rotary shaft in motional feedback. The second motor includes a magnet constituting a stator or a rotor, a coil disposed on the rotor side or the stator side with a predetermined distance from the magnet, and a predetermined distance from the magnet. and a magnetically sensitive element disposed on the rotor side or the stator side, and when the tone arm is not angularly displaced with respect to the tangential direction of the record, the magnetically sensitive element magnetizes the magnet. By selecting a positional relationship of the magnetically sensitive element with respect to the magnet so as to face a boundary portion of the tone arm, the magnetically sensitive element detects an angle of deviation of the tone arm with respect to a tangential direction of the record. and a detection output from the magnetically sensitive element is supplied to a drive coil of the first motor to perform linear tracking control of the tone arm by the first motor. record player.