JPS58182561A - Magnetic drum for rotation control and its manufacture - Google Patents

Abstract

PURPOSE:To improve apparent magnetic pole density, by dividing the circumference of a magnetic drum main body into plural stages, giving the respective stages physical shape variations at equal intervals, and shifting the physical shape variations of the respective stages in position. CONSTITUTION:The magnetic drum consists of two stages of ferromagnetic material base bodies 11A and 11B. Those ferromagnetic material base bodies 11A and 11B have sawteeth 13A and 13B at their outer circumferences at intervals (t) and the sawteeth of one stage shift in position from those of the other by t/2. Magnetic sensors are arranged at the circumference of the magnetic drum to detect the rotation of the magnetic drum.

Description

[Detailed description of the invention] In particular, it relates to FFI drums.

Conventionally, mechanical inertia has been used in devices that require high-precision constant-speed rotation in a rotating system, that is, extremely small rotations of wah-7-rat, such as VTRs, phono motors, chil recorders, and magnetic card readers. 7
2-I foil was often used. In addition, in recent years, with the development of electronic technology, there has been a desire for machines to be smaller and lighter, which has created a need for electronic control systems that generate high-density, highly accurate signals and that use inexpensive rotation sensors. Ta.
This rotation sensor is an optical sensor, for example, the outer circumference of the drum is divided into white and black stripes at equal intervals in the circumferential direction, and the strips are read by an optical sensor or read per unit time. A device is used that detects wow and flutter in the rotation system depending on the number of circular knits and feeds it back to the drive system to control constant speed rotation. However, such optical devices may cause reading errors when dust or other foreign matter contaminates the knitting section around the drum's periphery, and may also increase the pitch of the stripes (thin line stripes, etc.). It was difficult to make (manufacturing), and there were limits to improving the precision of rotation control.

Therefore, recently magnetic drums have been used to magnetize an integer number of magnetic bodies (magnetic films, magnetic rings) on the outer periphery at equal intervals, and use them as magnetic sensors (for example, conventional ring-shaped magnetic heads, Hall elements, magnetic resistance element, etc.), and detects a large bundle of wow and flutter in the rotating system based on the deviation of the number of a1 poles read per unit time, and feeds it back to the rotating system to remove the wow and flutter in the rotating system so that normal rotation continues. Control systems that perform K are attracting attention and are beginning to be used. Conventional magnetic drums used in this type of control system include:
Generally 7-F・2o3 or F・3o4 or C
Magnetic powder such as 7-r・, O,, F・3o4, etc. containing o is applied in the form of paint to the periphery of the drum body using the Ditub method, Megley method, etc. to a thickness of about 10-100 μm after drying. If so, the surface is polished to make it a magnetic material, and then magnetic poles are formed at equal intervals along the circumference of the magnetic material using a ring head (generally used magnetic recording head 1). There was something that became magnetized as if it were. There are various methods of forming magnetic poles on the magnetic material of such a magnetic drum, but one example is the synchronous magnetization method using a standard signal generation medium, which is described in Record research association fee department MR7 day, 20, a rotation sensor, l? It was disclosed in the 1979 io month aa issue.

In addition, Co, F@-cO are used as magnetic materials for magnetic drums.

Metals such as Nl, alloy thin films, etc. may be formed by chemical plating, electroplating, vapor deposition, spooling, and four-way sintering.Furthermore, magnetic metal plates are formed into a drum shape by sintering. has also been proposed.

There is also a method of forming a magnet (magnetic material filled with Pum-based or other polymer material at a high degree) into a cylinder shape and using it as a magnetic material on the circumferential surface of a drum, a method using Ba ferrite, cobalt ferrite, etc. A method has also been proposed in which sintered ferrite is formed into a ring shape, the circumferential surface of which is magnetized into equal parts, and the ring is formed into a magnetic drum.

However, in conventional magnetic drums of this type, the limit is that one to three magnetic poles can be formed per /IIm along the circumferential surface of the magnetic material, which is difficult to achieve with the precision that has recently been required. Since k to perform accurate rotational control is insufficient, a magnetic drum with higher magnetic pole density is required. 9. Conventional magnetic drums of this type require relatively laborious work such as synchronous magnetization using a standard signal generation medium when forming magnetic poles, and improvements are needed in this respect as well. It has been done.

In view of the above circumstances, an object of the present invention is to provide a magnetic drum which has a high m-pole density and does not require much effort to form magnetic poles.

It is an object of the present invention to provide a method for manufacturing a magnetic drum that can easily form such a magnetic drum.

According to the present invention, in a magnetic drum used for rotation control, etc., the surface of the drum body is divided into n stages in the direction of the rotation axis of the drum, and the distance between each stage is tK, etc. along the circumference of each stage. m magnets are formed in the interval, the position of the magnetic poles between each stage is even spaced apart from each other by a distance of -, and each magnetic pole is formed by the above-mentioned K as given by the physical shape change of the ferromagnetic material. objective is achieved.

9. According to #iK of the present invention, n disks of the same diameter are prepared, in which 4 magnetic poles of km equally spaced at tK can be seen along the curve, and the shape change of a ferromagnetic material is arranged like that of a physical salt. By stacking and fixing these disks concentrically in such a way that the positions of the magnetic poles are shifted from each other by a distance of -, a magnetic drum having the above-mentioned structure can be obtained. Can be easily manufactured.

Next, the present invention will be further explained with reference to embodiments of the present invention based on IiNgllK.

FIG. 7 is a schematic diagram of a flat 1iiFIA showing the relationship between a magnetic drum as an embodiment of the present invention, its magnetizing magnet, and its control head. It is a schematic perspective view which expands and shows a part of. Reference book 4#
1O is a magnetic drum having a rotation center @12 at the center of a disc-shaped ferromagnetic base 11. In this example, the outer periphery of the ferromagnetic substrate 11 is divided into RK parts in the direction of 6 x 2 during rotation, and an equal threshold area Krm 1 m is formed at an interval t around the circumference of each stage. Serrated teeth 13A and 13B
are formed, and the positions of the serrations are shifted from each other by a distance I between each stage.

Reference numeral 4 is a magnetic sensor, which may be a conventional ring-shaped read head used in the chip recorder 4, a Hall element, a magnetic resistance confection, or the like. In this case, the explanation will be based on a normal ring-shaped reading head.

If the width of the magnetic drum 10 in the direction of the center axis 12 of rotation is -4, then this reading head 4 extends at least this width dKj. When this magnetic drum 10 is rotated in the direction of arrow 8, I! 4j
The tips of the sawtooth teeth 13 and 1311 are magnetized by the nine permanent magnets 7 placed immediately in front of the rehead 4 to become magnetic poles. In II, the permanent magnet 7 has an N pole close to a serrated tip, but this may be an SIi or a DC electromagnet. Alternatively, the metal body of the base 11 may be saturated magnetized in advance so that magnetic 7 lux comes out from the tips of the serrated teeth 13 and 13B. In this way, the magnetic 72x from the tips of the circular sawtooth 1i1ii13 and 13B, which are used as magnetic poles, are stacked by the gap 5 of the thread stacking head 4, so that m+m=λm magnetic poles are read on the /circumference. This is K. Therefore, the number of serrated teeth 13A or 13B of each stage 11m and 11B of the magnetic body base 11 is m, regardless of whether it is 6, 9 or 4, and the reading range of one round of the magnetic drum 10. The number of magnetic poles produced is 4m, and the apparent density of the upper magnetic poles is doubled, making it possible to perform one-turn control with greater precision. That is, when the magnetic drum lO rotates, the signal C1 is generated in the head 4, and if the rotation is irregular, the time interval between the signals becomes irregular, and it becomes an electric signal, which indicates the rotation error. It can be sensed by writing.

In the above embodiment, the ferromagnetic base of the drum is divided into one stage and m serrations are provided over the circumference of each stage, but the ferromagnetic base of the drum is divided into three stages. Krm serrations are formed at equal intervals t along the circumferential direction, and the positions of the serrations in each stage are shifted by an interval τ between each stage. For example, magnetic drum/rotating machine rn+tn+m = 3 ys i! It can be made such that the pole can be read, and the appearance is the upper magnetic pole @! fIt can be tripled.

As is clear from this, according to the book @ Ming, t-! around the main body of the magnetic drum! Divided into I stages, 11iK wa ferromagnetic material shape changes are formed at equal intervals in each stage at intervals t, and the positions of the single shape change in each stage are separated by a threshold @i from each other. By shifting the magnetic poles K, it is very easy to create a magnetic drum with magnetic poles n times the magnetic pole density of each stage.

An example of a method for manufacturing such a magnetic drum will be explained shortly.

First, each R of the nine magnetic drums IO shown in FIG.
One of the same ferromagnetic disks constituting each of the 11 members and IIB is prepared. This ferromagnetic disk has a thickness of d (11
(see Fig. 11) is generally selected to be 0.3 to /, j-position.

Examples of the a-type magnetic material include granular magnetic materials such as r-F@1o, F@104, r-F*@On + reset containing Co, or 1. C,
7,1! - Light type, Ba 7 etite type, magnetic powder, and K is F・*Ni@C.

Metals, alloy powders, etc., are made into paint or ink, and formed on a base plate (metal, plastic, etc.) using a coating method, a metallic printing method, a sedge method, etc. The 11 people with 0 disks or IIB are
As shown in the figure, the tooth is formed into a serrated shape, and the large end of the tooth is divided into m4m with a spacing of 1310114 m and a distance of 1310114 meters. Of course, this disc may be made of a ferromagnetic metal cylinder or alloy, or a ferromagnetic thin film plated on a plate of metal, alloy, etc., and attached using a conventional method. -For forming the linear circumference, if it is a metal plate, nvn forming can be performed by punching or an etchender method, which is convenient for mass production.

Next, the same circular λ plates 11A and 11B are set so that their centers of rotation are the same, and as shown in Fig. 1, the tips of the teeth 13 of the circle @11A and the teeth 13310 of the disk 11B are
The tips are identified by shifting the interval by %t and overlapping them. Then, by installing a permanent magnet 7 that can magnetize the disk 11 and ILB at the same time, and a head 4 with a width that can be set as the main plate, the disk /
The number of signals generated in the head during rotation is xm.

This results in a magnetic drum having -m teeth, that is, a number of poles. Therefore, if n pieces of the same friend's disks are stacked, 1
When rotated, a magnetic drum capable of producing 61 am number of scratches is formed. Therefore, a magnetic drum having a desired number of magnetic poles can be formed by combining disks with the same pattern. This provides an industrially extremely effective method.

FIG. 3 shows another embodiment of the present invention, in which circular ferromagnetic pieces 24 are provided near the circumference at equal intervals at radial positions r from the center 22, and nine nonmagnetic substrate discs are formed. It is shown flatly. By overlapping such disks 21 with the ferromagnetic pieces 24 shifted from each other by K as described above, the magnetic drum as described above can be formed.

The reference figure is a modification of the disk in Figure 3, with a non-box base circle 1j.
This is an example in which triangular ferromagnetic pieces 34 are attached on the inner gutter in the same shape and at equal intervals instead of the circular ferromagnetic pieces 24 on the '31, and these discs 31 are similarly stacked on top of each other. By combining these elements, it is possible to construct a magnetic drum as described above.

In the disks of No. 711 and No. 4c, the base body 21 or 3
1 is made of a ferromagnetic material, a ferromagnetic material piece 24 or 34 is attached, and a hole is formed at a position corresponding to the tip 11111K by a punching die, an etching/deriving method, etc., and these are overlapped as described above. It is also possible to create a magnetic drum that has the same effect as that of the same machine.

[Brief explanation of drawings]

Figure 7 of the edited drawings shows the relationship among the magnetic drum, magnetizing magnet, and its sinking end as an embodiment of the present invention.
IIG plan view, Figure 1 is a schematic fIi+ view showing an enlarged part of the magnetic tram in Figure 1, Figure 3 is a book@
Schematic plan view showing a disc conveniently used in another embodiment of light, *4
Figure I is a schematic plan view showing a disc used in the example of Hon@Suzukinosara K+J. 4... Song tItiIR rehead, 5... Song...
・・・Earlug, 7・・・・・・Permanent magnet for magnetization,
1o...beat magnetic drum, 11...kawa...1 ferromagnetic material, 11mu, IZM...song 4! R stage disc, 12...-Rotation center axis, 13A
, 13B・・・・・・・・・−Uniform tooth

Claims (1)

[Claims] (1) In a magnetic drum used for 11 rotation control, etc. , the circumferential surface of the drum body is n in the direction of the rotation axis of the drum.
m magnetic poles are formed at regular intervals along the circumference of each stage at intervals t, and the positions of the magnetic poles between each stage are shifted from each other by a - interval). is a magnetic drum characterized by a change in physical shape of a ferromagnetic material. (2) The drum body is formed on a ferromagnetic substrate, and the magnetic poles are formed around the periphery of the wrinkled ferromagnetic substrate and are provided with nine serrated centers. ). (3) The ferromagnetic substrate is magnetically magnetized. The magnetic poles are formed of a non-magnetic substrate in which the flies are arranged, and the magnetic pole is provided by a ferromagnetic film provided on the sawtooth projections.
1) The magnetic drum described in item 1). (5) The drive body is basically formed of a ferromagnetic material,
Claim N(1), wherein the magnetic poles are provided by apertures formed and arranged near the periphery of the ferromagnetic substrate.
Magnetic drum as described in section. (6) The ferromagnetic substrate is saturated magnetized! [Magnetic drum described in (5). (The drum body is formed of a non-magnetic base,
Claim 1, wherein the magnetic pole is provided by ferromagnetic pieces arranged around the non-magnetic base. jl
Magnetic drum described in HIJ section. (8) In a method of manufacturing a magnetic drum used for rotation control, etc., physical shape changes of a ferromagnetic material that can provide m magnetic poles at equal intervals tic along the circumferential surface are arranged, and nine of the same diameter are arranged. A patent characterized in that n discs are prepared, and these discs are concentrically superimposed and fixed such that the positions of the magnetic poles are shifted by a distance of - between each disc. How to make rum. (9) The disk is formed of a ferromagnetic substrate, and the magnetic poles are provided by sawtooth projections formed and arranged around the ferromagnetic substrate. Method of manufacturing magnetic drums. αC The ferromagnetic substrate is saturation magnetized. Claims @ (9) The manufacturing method of a magnetic drum according to claim 9. αυ The disk is a non-magnetic substrate with sawtooth-like protrusions arranged around one periphery. Claims 1! l
ji (method for manufacturing a magnetic drum according to item 81. α-yu) The disk is formed of a single ferromagnetic material, and the magnetic poles are provided by apertures formed and arranged near the periphery of a suppressive ferromagnetic substrate. A method for manufacturing a magnetic drum according to claim 81, wherein the ferromagnetic substrate is saturated magnetized. The method for manufacturing a magnetic drum according to claim (8), wherein the plate is formed of a non-magnetic base, and the magnetic poles are provided by ferromagnetic pieces arranged around the non-magnetic base. .