JPS6117567Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape recorder, and particularly to a drive structure for a reel stand.

A tape recorder performs winding, fast forwarding, and rewinding during recording and playback by selecting and rotating two reel stands. In this case, the reel stand drive system for tape recorders that has been commonly used in the past is an indirect drive system in which a rotating body connected to a motor shaft is rotated by pressing it against a selected one of two reel stands. There is a direct drive system in which a motor is provided corresponding to each reel shaft and the rotating shaft of this motor is directly connected to the reel shaft. In this case, comparing both formulas,
Direct drive systems are superior in terms of reliability and performance. Even in this direct drive system, the drive motor can be classified into brush motors and brushless motors depending on the type of drive motor. In this case, brush motors are relatively inexpensive but have problems with their characteristics such as shaft loss and torque ripple, while brushless motors have extremely good characteristics but are expensive.

Therefore, an object of the present invention is to obtain a direct drive type tape recorder using a brushless motor at low cost.

In order to achieve such an object, the present invention provides a direct drive system using a brushless motor while sharing the stator member and drive circuit that constitute the brushless motor on the take-up side and the supply side. Hereinafter, the tape recorder according to the present invention will be explained in detail with reference to the drawings.

The figure is a plan view showing an embodiment of a reel stand driving section which is a main part of the tape recorder according to the present invention.
1 is a reel stand shaft on the take-up side, and a ring-shaped inner yoke 2 is attached to the outer circumference of this reel stand shaft 1.
are fixed coaxially. Reference numeral 3 denotes a ring-shaped rotor magnet coaxially fixed to the outer circumference of the inner yoke 2, and the rotor magnet 3 has S and N poles alternately magnetized along the circumferential direction on its outer circumferential surface. There is. Reference numeral 4 denotes a reel stand shaft on the supply side, and an inner yoke 5 and a rotor magnet 6 are fixed coaxially to the outer periphery of the reel stand shaft 4, similarly to the take-up side described above. Reference numeral 7 denotes a rotating shaft that is provided at an intermediate position between the reel shafts 1 and 4 and perpendicular to the shafts, and is rotated through 180 degrees by the take-up drive and supply drive operations. Reference numeral 8 denotes an arm whose central portion is fixed to the rotating shaft 7, and whose both ends extend to the positions of the reel stand shafts 1 and 4. Reference numeral 9 denotes an outer yoke provided at one end of the arm 8, and the outer yoke 9 is arc-shaped so as to follow the circumferential surfaces of the rotor magnets 3 and 6 at a predetermined distance apart. Reference numeral 10 denotes a hysteresis material provided at the other end of the arm 8, and this hysteresis material 10 has an arcuate shape along the circumferential surfaces of the rotor magnets 3 and 6 at a predetermined distance apart. Reference numeral 11 denotes 2 arranged on the inner surface of the outer yoke 9, that is, the surface facing the rotor magnet 3, corresponding to the magnetization pitch of the rotor magnet 3.
stator coils, 12 stator coils 11
The timing of supplying the drive current to the stator coil 11 is determined by detecting the magnetic pole of the rotor magnet 3 and supplying the detected magnetic pole to a drive circuit (not shown).

In the device configured as described above, when power is supplied to the motor drive circuit (not shown) in the illustrated state, the motor drive circuit responds to the magnetic detection signal output from the magnetic detection element 12 in the same way as a known brushless motor. Select the stator coils and energize them sequentially. As a result, a magnetic force acts between the magnetic velocity generated by the stator coil 11 and the magnetic poles on the rotor magnet 3, causing the rotor magnet 3 to rotate. When the rotor magnet 3 rotates, the inner yoke 2 and the reel spindle 1 fixed inside the rotor magnet 3 rotate, and the magnetic tape is wound toward the take-up side. In this case, on the supply side, since the hysteresis material 10 is close to the outer periphery of the rotor magnet 6, the magnetic tape is rotated in the direction of the arrow by being returned, and the hysteresis material 10 is connected to the rotor magnet 6. Material 10
A hysteresis magnetic effect works between the two. As a result, a braking action is applied to the rotor magnet 6,
Prevents the tape on the supply side from loosening more than necessary.

Next, when a rewinding operation is performed using a lever (not shown) or the like, the rotation shaft 7 moves as shown by the arrow.
Rotates 180° and locks in place. As a result, the stator coil 11 is located on the outer periphery of the rotor magnet 6 on the supply side, and the hysteresis material 10 is located on the outer periphery of the rotor magnet 3 on the take-up side. In this state, when a motor drive circuit (not shown) is activated, the rotor magnet 6 on the supply side is rotated in the direction opposite to the arrow. In other words, although the order of excitation of the stator coils 11 by the motor drive circuit is the same, the positions of the pair of stator coils 11 are reversed, so that they are reversed. In this way, as the rotor magnet 6 on the supply side rotates, the reel stand shaft 4 fixed inside the rotor magnet 6 winds the magnetic tape on the supply side. Therefore, in the device configured in this way, the stator part and its drive circuit system can be shared among the brushless motors on the take-up side, the supply side, and the supply side, and as a result, the structure is simple and A tape recorder using a direct drive system can be obtained at low cost. Note that the rotational speed of the reel spindle can be freely controlled by the speed of selective excitation of the stator coil by the drive circuit, so that operations during winding and rapid forwarding can be performed freely. Furthermore, in the above embodiment, a hysteresis material is provided at one end of the arm 8, and a hysteresis brake is applied to the rotor magnet located opposite to the rotor magnet facing the stator coil 11, thereby adding safe back tension. As described above, if such an action is not required, the length of the arm 8 can be halved, and the radius of rotation of the arm 8 can be halved, making it possible to further improve the device. It can be made smaller.

As explained above, the tape recorder according to the present invention has a rotor magnet installed on the shafts directly connected to the reel stands on the take-up and supply sides, and the tip of the arm that rotates at the center between the two shafts. A stator member consisting of a stator coil and a position detection element is disposed on the rotor magnet, and the stator member is selectively positioned on the outer periphery of the rotor magnet on the take-up side and the stator side, thereby rotating the rotor magnet. To,
A tape recorder using a direct drive method using a brushless motor that is inexpensive, simple in structure, and stable in operation, allowing the stator coil, position detection element, and drive circuit to be shared between the brushless motors on the take-up and supply sides. is obtained. Furthermore, by arranging a hysteresis member at the other end of the arm, various excellent effects can be obtained, such as being able to apply stable back tension to the rotor magnet on the delivery side.

[Brief explanation of the drawing]

The figure is a plan view of essential parts showing an embodiment of the tape recorder drive mechanism according to the present invention. 1, 4... Reel stand shaft, 2, 5... Inner yoke, 3, 6... Rotor magnet, 7... Rotating shaft, 8... Arm, 9... Outer yoke, 10...
Hysteresis material, 11...Stator coil, 12
...Position detection element.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Rotor magnets provided on shafts directly connected to the reel stands on the take-up and supply sides, respectively, and an arm that rotates between the two rotor magnets, The arm has a stator section provided at the end thereof and facing a part of the outer periphery of the rotor magnet, and the stator section is composed of a stator coil and a position detection element, and the stator section A tape recorder characterized in that the tape recorder is selectively located on the outer periphery of a rotor magnet on the take-up and supply sides. (2) The tape recorder according to claim 1, which is characterized by having a hysteresis member at the other end of the arm.