JPS63198569A - Head feeding mechanism - Google Patents

Abstract

PURPOSE:To reduce the cost and to save the space of a head feeding mechanism by accessing by supplying a current only to a main coil at the time of reproducing, and using both the main coil and an auxiliary coil at the time of attaching or detaching a recording medium. CONSTITUTION:A head 1 is guided by two shafts 2, 3 to be slidably supported. A yoke 4 for forming a voice coil motor for sliding the head 1 is formed in a U-shaped section, and magnets 5, 6 are magnetized in its thicknesswise direction. A main coil 7 and an auxiliary coil 8 are wound substantially parallel to the surfaces of the magnets 5, 6, and secured to the head 1. Thus, a structure which prevents a recording medium or a housing for protecting the medium from interfering with the head at the time of attaching or detaching the medium can be simplified.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to magnetic or optical recording devices.

[Conventional technology]

In conventional magnetic or optical recording devices with replaceable recording media, when replacing the recording medium, the head, its attachments, or the carriage supporting the head interfere with the recording medium or the body that protects the recording medium due to the operation of attaching and detaching the recording medium. In order to prevent this, the following two methods have been mainly used. In other words, the first method is to move the movable range of the voice coil motor beyond the recording range and further away from the center of rotation of the recording medium, so that the entire carriage or the recording medium can be protected when loading or unloading the recording medium. This is to prevent mutual interference during attachment and detachment by evacuating to a position far away from the national polity. The second method uses a movable mechanism for the head, its accessories, or a part of the carriage, so that when a recording medium is attached or removed, only the parts that cause interference are moved to avoid interference. Figure 3 shows an example of the second method described above, and is an example of a floppy disk drive in which the upper head is raised to the position indicated by the imaginary line in the figure to prevent interference when changing disks. .

[Problem that the invention seeks to solve]

However, each of the above-mentioned conventional techniques has the following problems. First, in the first method of the prior art mentioned above, the movable range of the feed mechanism must be longer than the length required for recording and reproducing information (sometimes more than twice as long). The volume of the voice coil motor simply increases by the extension of . In other words, if it is necessary to retreat by the same distance as the recording range when attaching and detaching, the volume of the voice coil motor will need to be twice as large. Voice coil motors designed to produce large amounts of force in order to achieve high-speed access often use expensive materials for their magnets, and this method is not only extremely disadvantageous in terms of cost (it also reduces the cost of the entire device). Increased volume and weight (magnets and magnetic path members also have high specific gravity) are also major problems.The second method is to use a magnetic recording head or transmitted light reproduction method in the movable part to prevent interference. If a component that requires high positional accuracy, such as a detection element of a magneto-optical recording head, is cut out, the positional deviation due to the movable structure will be r3.
M, which necessitates the use of a high-precision movable mechanism, or a structure that moves upward by rotational support as shown in FIG. 3 has problems such as hindering the overall thickness of the device. Therefore, the present invention provides a feeding mechanism that solves these AM points and provides a function to prevent interference when loading and unloading a recording medium at a low cost and in a small space, and without loss of functionality such as accuracy. The purpose is to

Means for solving CIQlff 1 point] The feeding mechanism of the present invention is a magnetic or optical recording device that uses a voice coil motor as a head feeding mechanism and has an exchangeable recording medium, in which both surfaces are approximately the same plane or the same curved surface. Furthermore, two magnets are arranged such that their magnetization directions are in the normal direction of the plane or curved surface and their directions are opposite to each other, supporting the magnets and a functional basic structural part thereof. A magnetic path member that has a U-shaped cross section when taken in a plane perpendicular to the direction of movement of the head; The main coil is supported and fixed to the carriage on which the head is placed, and the auxiliary coil is supported and fixed to the head or the carriage on which the head is placed so that the wound surface of the coil is located approximately in the same plane as the main coil. It is characterized by becoming.

(Function) According to the above configuration of the present invention, only the main coil is energized for access during recording and playback, and both the main coil and the auxiliary coil are used when loading/unloading the recording medium. The head or the carriage on which the head is mounted can be retracted to a position where interference does not occur beyond the area (area).

〔Example〕

FIG. 1 is a perspective view showing an embodiment of the present invention.

A head 1 is housed and slidably supported on two shafts 2.3. The yoke 4, which is a magnetic path member constituting a voice coil motor that generates a force for sliding the head 1 along the shaft 2.3, has a U-shaped cross section. In FIG. 1, the voice coil motor components other than the yoke are hidden behind the yoke 4 and cannot be seen. FIG. 2 is a perspective view with the yoke removed. The magnets 5 and 6 are separated in the thickness direction, their magnetization directions are opposite to each other, and their surfaces are generally on the same plane. The main coil 7 and the auxiliary coil 8 are wound so as to be substantially parallel to the surfaces of the magnets 5 and 6, and are each fixed to the head 1. In this figure, the bobbin that fixes the coil to the head is omitted.

Here, the desirable sizes of the two magnets, the main coil, and the auxiliary fill will be explained using FIG. 4.

The lengths a and b of the magnets are the same length, and if S is the length that the head should move during recording and reproduction, it is the same as or slightly longer than the sum of S and the width g of the main coil. The gap C between the magnets is not essential, but is set as necessary when designing the magnetic circuit so that the strength of the magnetic field is constant within the range of movement of the coil. The length d of the main coil is alcqg
The length is the sum of . Next, the distance f between the main coil and the auxiliary coil is determined by subtracting g and the width of the auxiliary coil from &. The length e of the auxiliary coil is equal to or longer than the sum of C, g, and h, and is up to the maximum length d. At this time, the head retractable distance t when attaching and detaching the recording medium is 2 of h, which is the sum of a and e.
The distance is calculated by subtracting the length. Expressing these in formulas, a=b≧5+g, c≧O f=a−g−hX2 e≧C+g+h, e≦d t=a+e−hX2. Here, S is the recording area length, and t is the head retractable distance. These dimensions are merely a guideline that serves as a design standard; in reality, it is desirable to find the optimal dimensions by taking various factors into account, and the dimensions are not limited to the values shown here.

Next, we will explain how to retract the head during attachment/detachment using the auxiliary coil. FIG. 5 is a diagram showing (a) to (e) the positional relationships between the magnets 5 and 6 and the main coil 7 and auxiliary coil 8 when the head is in various positions. When the head is in the state between (a) and (b) in Figure 5, it is the normal access range for recording and reproducing. Access is controlled. That is, when a current is passed in the direction of arrow 11, the head receives a force in the direction of white arrow 9. Conversely, when a current is applied in the direction of arrow 12, the head receives a force in the direction of white arrow 10. When loading/unloading a recording medium, first move the head to position (b), then apply current to the auxiliary coil in the direction of arrow 13, the head receives force in the direction of white arrow 9, and moves the auxiliary coil to position (C). You can move the head by . Next, when a current is applied to the main coil 7 in the direction of the arrow 12, the head receives a force in the direction of the outlined arrow 9 and is moved to the position (d). Furthermore, by passing current through the auxiliary coil in the direction of arrow 14, the head can move to (e). This 3
Retract the head by step by step. Also, by following these steps in reverse, it is possible to return from the retreat position (e) to the normal access range (b).

In other words, when the head is in the position (e), if a current is applied to the auxiliary coil in the direction 13, the head receives a force in the direction of the white arrow 10 and can be moved to the position (d). If a current is passed through the coil in the direction of arrow 11 (C
) The head can be moved to the position shown in (b), and if a current is applied to the auxiliary coil in the direction of arrow 14, the head can be moved to the position shown in (b).

The above is an explanation of the configuration and operation of one embodiment of the present invention. In the above explanation, three steps are used to retract the head, but it goes without saying that if the retraction distance is short, it is possible to configure the head retraction with only one or two steps. .

Next, other embodiments will be briefly described. In the above embodiment, the head moves linearly while being guided by two shafts, but there is a rotational guide method for the head that is often used in hard disk drives. This is a method in which the head is moved by rotation around a central axis supported by ball bearings or the like. The shapes of the yoke, magnet, main coil, and auxiliary coil when the present invention is applied to such a head movement system are shown in Fig. WE. In this example, each component has a curved shape along a concentric cylindrical surface centered around the rotation center of the head.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, the parts and structures necessary to add the function of preventing interference between the recording medium or the head or carriage that protects the recording medium and the head or carriage when the recording medium is attached or detached can be extremely simplified. Therefore, it is possible to obtain great effects such as a reduction in parts cost, a reduction in the weight of the device, a reduction in the size of the device, and an improvement in reliability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention. FIG. 2 is a perspective view of FIG. 1 with the yoke removed. FIG. 3 is an operation diagram showing a conventional example. FIG. 4 is a plan view showing the dimensions of the magnet and coil. FIGS. 5(a) to 5(e) are operational diagrams showing the positional relationship between the magnet and the coil. FIG. 6 is a perspective view showing a voice coil motor according to another embodiment of the present invention. l...Head 2.3...Shaft 4...Yoke 5.6...Magnet 7...Main coil 8...Auxiliary coil and above Seiko Epson Corporation vJ 1 Figure 2 solid

Claims (1)

[Claims] In a magnetic or optical recording device that uses a voice coil motor as a head feeding mechanism and has an exchangeable recording medium, the surfaces thereof are approximately the same plane or the same curved surface, and the direction of magnetization is set to the plane mentioned above. Alternatively, two magnets are arranged in the normal direction of a curved surface and opposite to each other, and the shape of the basic functional structure that supports the magnets is taken in cross section on a plane perpendicular to the direction of movement of the head. The magnetic path member has a U-shape, the main coil is supported and fixed to the head or the carriage on which the head is mounted, so that the wound surface of the coil is parallel to the surface of the magnet, and the coil is A head feeding mechanism comprising an auxiliary coil supported and fixed to a head or a carriage on which the head is mounted so that the wound surface thereof is located approximately in the same plane as the main coil.