JPS6361310A - Position detecting device - Google Patents

Abstract

PURPOSE:To correctly detect the position of a conveyer by synthesizing an output signal in the prescribed section of the conveyer and the facing detecting output signal of a body to be detected and a sensor. CONSTITUTION:A stepping motor 15 is fitted at a chassis 3 and a screw shaft 16 to etch a spiral groove 17 at the outer circumference is penetrated and bonded to a rotor magnet 18. A connector 20 is fitted at a carrier 1 to load a magnetic head 2, the tip part is fitted into the spiral groove 17 of the above- mentioned shaft 16 and the carriage 1 is reciprocating-conveyed. At the chassis 3, a mechanical switch 21 is fitted, a magnet 23 for a sensor is provided at the prescribed position of the rotor magnet 18 and a magnetic sensor 24 is provided at the position facing to this. Further, the position relation of the above-mentioned magnet 23 and the magnetic sensor 24 is set so that both 23 and 24 can be faced, when the connector 20 is fitted into a groove part 26 in which a lead angle is zero. Thus, the output signal of the switch 21 and the magnetic sensor 24 is synthesized and a correct position detection can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position detection device suitable as, for example, O-track position detection means for a magnetic disk drive device.

[Conventional technology]

In a magnetic disk drive device, a carriage carrying a magnetic head is transferred in the radial direction of the magnetic disk by a carriage transfer mechanism, but in order to accurately transfer this carriage and enable desired tracking control, It is necessary to detect that the magnetic head is at the O track position of the magnetic disk. That is, by using this detected position as a reference, it is possible to move the carriage (magnetic head) to a desired position, thereby performing desired recording and reproduction.

Therefore, as a position detection device for detecting via the carriage that the magnetic head coincides with the 0 track position, conventional magnetic disk drive devices include an optical sensor that can be configured to detect that the carriage is at a predetermined position. A sensor such as a magnetic sensor is provided. This sensor has a high positional accuracy of 61° when installed by finely adjusting the mounting position while actually aligning the magnetic disk with the O track position.
It is designed to be maintained.

FIG. 4 is a plan view of a main part of a magnetic disk drive device showing a conventional example of such positional lateral mounting. In the figure, a carriage 1 is equipped with a magnetic head 2. This carriage 1 is slidable along a guide shaft 4 fixed to a chassis 3, and a stepping motor (not shown) is used to track the magnetic disk. It is designed to be transported in the direction. Reference numeral 5 designates a rectangular adjustment plate, and one end of this adjustment plate 5 is rotatably supported on the chassis 3 by a countersunk screw 6 serving as a rotation fulcrum.
At the other end, an actuating portion 7 is formed with a notch. The adjustment plate 5 between the actuating portion 7 and the countersunk screw 6 is provided with a dark blue elongated hole 8 in the axial direction of the guide shaft 4, and a fixing screw 9 is inserted through this elongated hole 8. The adjustment plate 5 is fixed to the chassis 3 by being fastened to the chassis 3. Reference numeral 0 denotes a detection object placed and fixed on the adjusting plate 5 near the countersunk screw 6, and a light emitting diode and a phototransistor (both not shown) are connected through a groove 11 formed in the center of the detection object 10. ) is built into the detection body 10. Further, a piece-shaped detected portion 12 is protruded from the rear end of the carriage l, and this detected portion 12 is moved into the groove by movement of the carriage 1.
It is now possible to appear within 1. Note that 13 is a conical groove-shaped guide portion formed in the chassis 3, and this guide portion 13 is located on an extension line of the flat head screw 6 and the screw 9.

In the above borrowing, when an adjustment disk (not shown) on which a recording trough serving as a reference is formed is used and the reference recording track is read and scanned by the magnetic head 2, the head 2 is used as the recording track that serves as the position reference of the O track. Since the detected part 12 of the carriage 1 can be aligned with the track, that is, the O-track position, the detected part 12 of the carriage 1 can be aligned with the groove 11 of the detection body 10 at this position.
If the sensor is made to operate by entering the sensor and blocking the light from the light emitting diode, the position where the sensor detects the detected portion 12 will be the O-track position of the magnetic head 2 from now on.

Therefore, the mounting position of the detecting body 10 (sensor) relative to the detected part 12 is accurately adjusted with the magnetic helad 2 aligned with the O track position using a recording disk. This adjustment work is performed using an adjustment driver 14 having a protrusion at the tip.
With the screw 9 loosened, engage the protrusion of the adjustment driver 14 with the guide part 13, and use the protrusion as a fulcrum to move the adjusting screwdriver 14 along arrow A in FIG. This is done by rotating in the B direction. Adjustment driver 14
When the adjustment plate 5 is rotated, the operating portion 7 comes into contact with the adjustment driver 14, so that the adjusting plate 5 is rotated in the direction of arrows C and D in FIG. As a result, the positional relationship between the detecting object 10 mounted on the flattener 5 and the detected portion 12 protruding from the carriage 1 can be precisely aligned. Then, by finally tightening the screws 9, the flF1 adjustment work is completed. This S
j Adjustment work is performed using the actuating part 7 located away from the countersunk screw 6.
It is designed so that by rotating the counter screw, the circular displacement view of the detection body 10 mounted near the countersunk screw 6 becomes smaller, that is, minute displacement adjustment becomes possible.

In addition, as a reference known example of the above-mentioned position detection device, the one described in Japanese Utility Model Application Publication No. 60-9066 can be mentioned.

[Problem that the invention seeks to solve]

By the way, in recent years, FFFF disks have become more and more densely packed, for example, 135 tracks per inch (135 tracks per inch).
57P I), the track width is extremely narrow. For this reason, even if the position detection device is capable of minute displacement adjustment like the conventional technology described above, skill is required for the adjustment work, and furthermore, the effect of misalignment when tightening the screw 9 cannot be ignored. However, it took time to make adjustments, leading to an increase in costs. Furthermore, since there is a limit to the resolution of the sensor itself, if the density of magnetic disks becomes even higher, there is a risk that accurate sensing will not be possible even if the sensor is installed at the proper position r.

Therefore, it is an object of the present invention to provide a position detection device that solves the problems of the prior art described above and can perform accurate sensing without requiring complicated adjustment work.

[Means for solving problems]

In order to achieve the above object, the present invention provides a position detection device for detecting that a transfer body linearly transferred by a rotating shaft of a transfer mechanism is at a predetermined position. a first detection means that emits a signal when located in the vicinity; a detected object integrated with the rotating shaft; and a sensor that emits a signal when facing the detected object during one rotation of the rotating shaft; a second detection means consisting of;
The configuration includes signal processing means for synthesizing output signals from these first and second detection means.

[Effect]

According to the above means, when the transporting body is transported and reaches a certain position, the first detection means emits a signal, but even if the rotating shaft is rotated forward and the transporting body is further transported, the first detection means will remain in the first position for a while.
Since the output signal from the detection means is sustained, the time when the detected object and the sensor face each other during this time, that is, the time when the second detection means transmits the signal while the first detection means is emitting the signal can be determined. The position of the transport object at that time can be detected accurately.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of essential parts of a magnetic disk drive device showing one embodiment of a position detection device according to the present invention, FIG. 2 is a front view of a screw shaft used in this magnetic disk drive device, and FIG. 3 is a front view of a screw shaft used in this magnetic disk drive device. It is a side view of the same screw shaft, and parts that are equivalent or can be considered equivalent to those in FIG. 4 are given the same reference numerals.

In FIG. 1, 15 is a stepping motor attached to the chassis 3, and 16 is a screw shaft with a spiral groove 17 carved on its outer periphery. This is a well-known screw shaft 16, which passes through and is fixed to a cylindrical rotor magnet 18, which is the rotor of the stepping motor 15. The end of the screw shaft 16 is supported by a bearing 19.

The holder 20 is attached to the carriage 1 on which the magnetic head 2 is mounted. The tip of the holder 20 is fitted into the helical groove 17 of the screw shaft 16.
When the screw shaft 6 is rotated in the forward and reverse directions, the engaging element 20 moves in the direction of the arrow shown in the figure, and as a result, the carriage 1 is reciprocated along the guide shaft 4 by an amount corresponding to the amount of rotation of the screw shaft 16. Reference numeral 21 denotes a mechanical switch attached to the chassis 3, which is turned on when the knob 22 of the switch 21 comes into contact with the carriage 1 and is pressed. 23 is a sensor magnet protruding from a predetermined position of the rotor magnet 18, and 24 is a Hall element, which is a magnetic sensor, fixed at a position where it can face the magnet 23, and which supplies driving power to the winding coil 25. When the rotor magnet 18 is rotated, there is a position where the sensor magnet 23 faces the Hall element 24 once during one rotation, and at that time the Hall element 24 outputs a pulse.

Next, the screw shaft 16 will be explained in more detail using FIGS. 2 and 3. As shown in these figures, over a predetermined range on the outer periphery of the screw shaft 16, there is a groove portion 26 that is parallel to the vertical vAY perpendicular to the axis X, that is, has an advance angle, and has a straight groove bottom. are provided at equal intervals along the circumferential direction of the shaft 16, and these grooves 26 are
These grooves 2 are successively arranged in a sequentially shifted state in the axial direction of the shaft 16 so that the insides of the shafts 16 communicate with each other, and as a result, these grooves 2
6, one spiral groove 17 is formed. Furthermore, a feeding portion 27 through which the carriage 1 is fed is formed at each connection portion of these groove portions 26. When the screw shaft 16 is rotated, the engaging element 20 attached to the carriage 1 and fitted into the spiral groove 17 slides, and when the engaging element 20 slides within the feeding section 27, a predetermined The carriage 1 is transported in accordance with the advance angle of
When the engaging element 20 comes into the groove 26, the stepping motor 15 is de-energized and the carriage 1 stops moving. In this way, since the screw shaft 16 is intermittently rotated by 1/8 pitch and the advance angle is zero in the groove portion 26, the carriage 1 can be intermittently fed along the axis vAx with high positional accuracy. It has become so.

Further, the sensor magnet 23 and the Hall element 2
The positional relationship with 4 is set such that both 23 and 24 face each other when the engaging element 20 is fitted into the groove 26 where the advance angle is zero.

In other words, when the screw shaft 16 rotates once, 1/
The engaging elements 20 are sequentially fitted into the eight grooves 26 that are shifted by 8 pitches. At this time, the sensor magnet 23, which rotates together with the screw shaft 16, is fitted into any of these eight grooves. When the engaging element 20 is inserted into one of the grooves 26, it faces the Hall element 24, and thereafter, each time the screw shaft 16 rotates once, the engagement element 20 faces the Hall element 24.
3.degree. 24 will face each other, and when they face each other, a pulse is generated from the Hall element 24 and output to a signal processing circuit (not shown).

On the other hand, the mechanical switch 21 is connected to the magnetic head 2.
When the carriage 1 is moved so that it comes to the O track position, the carriage 1 comes into contact with the knob 22 and turns on, but since the resolution of the mechanical switch 21 itself has a limit, this is all that is required. The zero track position cannot be detected accurately. However, it is easy to set the mechanical switch 21 so that the 0 track position is reached during one rotation of the screw shirt 16, that is, within a range of 8 tracks, even when the track width is extremely narrow. , and screw shaft 1
8 tracks during one rotation of 6 are sensor magnet 2
3 and the Hall element 24 when they face each other, the output signal from the mechanical switch 21 and the output signal from the Hall element 24 can be combined by a signal processing circuit (not shown). This enables accurate O-track position detection. Therefore, there is no need to make fine adjustments to the mounting position as in conventional position detection devices, and there is no need to worry about lowering detection accuracy or complicating installation work even if the density of magnetic disks increases.

Furthermore, the spiral shape of the screw shaft 16? For example, the grooves s17 may be formed by consecutive grooves that are sequentially shifted by 1/6 pitch. Further, the resolution of the mechanical switch 21 only needs to satisfy the condition that the Hall element 24 outputs a pulse once during its ON operation.

Furthermore, although the above embodiment employs a magnetic detection method that combines the sensor magnet 23 and the Hall element 24, a photodetection method may be used instead of this, and instead of the mechanical switch 21, other devices may be used. It is also possible to apply sensing means.

〔Effect of the invention〕

As explained above, the position detection device according to the present invention receives an output signal from the first detection means for detecting that the conveying object being transported by the rotating shaft is within a predetermined section, and a position detecting device that rotates integrally with the rotating shaft. The position of the transport object within the predetermined section can be accurately detected by combining the output signal from the second detection means that detects that the object to be detected faces the sensor. Unlike conventional position detection devices, there is no need to fine-tune the mounting position (this greatly improves the installation work), and high-precision detection is possible, for example, for magnetic disks compatible with high density disks. If applied to the O-trace 99 position detection mechanism of a drive device, remarkable effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of essential parts of a magnetic disk drive device showing one embodiment of a position detection device according to the present invention, FIG. 2 is a front view of a screw shaft used in this magnetic disk drive device, and FIG. 3 is a front view of a screw shaft used in this magnetic disk drive device. Side view of the same screw shaft, No. 4
The figure is a plan view of a main part of a magnetic disk drive device showing an example of a conventional position detection device. 1... Carriage, 2... Magnetic head, 15...
Stepping motor, 16... screw shaft,
17...Spiral groove, 18...Rotor magnet, 2
0... Engagement element, 21... Mechanical switch, 22
...Knob, 23...Sensor magnet, 24...
-Hall element, 26...groove section, 27...feeding section.

Claims (1)

[Claims] A position detection device for detecting that a transfer body linearly transferred by a rotating shaft of a transfer mechanism is at a predetermined position, which emits a signal when the transfer body is located at or near the predetermined position. a first detection means; a second detection means comprising a detected object integrated with the rotating shaft; and a sensor that faces the detected object and emits a signal during one rotation of the rotating shaft.
1. A position detection device comprising: detection means; and signal processing means for synthesizing output signals from the first and second detection means.