JPS6233515Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a frame in which an annular outer core surrounds the radial outer peripheral surface of a cylindrical inner core, and can rotate within a magnetic gap formed by these two cores. More specifically, the moving coil device of this invention has a higher torque than moving coil devices used in indicating instruments, etc., and can be used at high speeds. The present invention relates to a moving coil device used as a pen motor for pen oscilloscopes and the like that require repetitive motion.

Examples of these conventional devices will be described with reference to FIG. 1. An outer core 2 is provided surrounding an inner core 1, and the inner core 1 is supported by the outer core 2 by a non-magnetic mounting member (not shown). , or attached to a holding member (not shown) of the outer core 2. A coil 4 wound around a coil frame 3 is disposed inside the magnetic gap formed by the inner core 1 and the outer core 2. The centers of rotation are respectively locked to coupling fittings 5 and 5'. The shafts 6, 6' connected to the coupling fittings 5, 5' are rotatably supported by bearings 8, 8' provided on the upper and lower lids 7, 7', respectively. A lead wire of the coil 4 is drawn out through the shaft 6. As you can see from the above explanation,
The shafts 6, 6' are supported separately by the upper and lower lids 7, 7', and the lids 7, 7' require considerable thickness for strength, making it difficult to see inside when assembled. As a result, so-called "centering" of both shafts 6, 6' is extremely difficult, and some degree of axis misalignment is unavoidable. In addition, in this type of moving coil device, if a recording pointer is attached to the upper shaft 6 and a potentiometer or the like is attached to the lower shaft 6', the moving coil 4 can move repeatedly at high speed. Then, the upper and lower shafts 6, 6' are connected via this moving coil 4 itself.
Torque is transmitted to the movable coil 4, but since the inertia of the upper and lower shafts 6, 6' differs due to the attachment of a pointer, potentiometer, etc., a torsional force acts on the moving coil 4. If the movable coil 4 is twisted by this torsional force, the rotation angles of the upper and lower shafts 6, 6' will no longer match. Therefore, the positional relationship between the pointer and the potentiometer connected to the shafts 6, 6' changes, deteriorating the accuracy of the meter. For this reason, in the conventional device, the coil frame 3 has been used even though it increases the weight.

As is well known, the rotational torque generated in the coil when current is applied depends on the size of the magnetic gap, and it has been desired to make the gap as small as possible. However, in the conventional device, as is clear from the above explanation, since the coil frame 3 and the coil 4 are interposed within the magnetic gap, the magnetic gap has to be increased by the thickness of the coil frame 3. was never a good thing. Some conventional devices include a coil frame 3
Instead of this, there is a method in which the coil 4 is hardened using a hardening resin, but if the amount of resin is small, even if the thickness of the coil can be made thin, it will not help prevent twisting, and therefore the amount used will increase. As a result, there was no significant difference from the case where the coil was wound around the coil frame.

As mentioned above, in conventional devices, the major challenges were to reduce the weight of the coil and to reduce the magnetic gap.

This idea was made in consideration of the above points,
The purpose was to create a lightweight moving coil with negligible torsion and no need for a coil frame, and to achieve high-sensitivity and high-speed recording by reducing the magnetic gap. The purpose of the present invention is to provide a moving coil device that makes it possible.

Hereinafter, an embodiment of this invention will be explained in detail with reference to FIGS. 2 and 3.

In this embodiment, the inner core 21 consists of a cylindrical yoke, and two annular outer cores surround the inner core 21 with a predetermined magnetic gap in between. 22, 23 and
A case 24 for holding them is provided. A permanent magnet is used for the outer core 22, and the outer core 23 is made of a yoke.
They are integrally constructed so that the mutual magnetic resistance is negligible. The materials used for each core in this embodiment are as described above, but permanent magnets may be used for the inner core, and yokes may be used for all the outer cores. Further, the number of cores constituting the external core is not limited to two, and can of course be arbitrarily selected depending on design conditions.

At the center of the internal core 21, this internal core 2
A hole 25 communicating with the upper and lower surfaces of the hole 25 is bored, and recesses 26 and 27 are provided at the open ends of the hole 25, respectively, concentrically with the hole 25. Then, the shaft 28 is inserted into the hole 25, and both ends of the shaft 28 are fitted into bearings 29 fitted into the recesses 26 and 27, respectively, so that the shaft 28 is rotatably supported at the center of the inner core 21. ing. Coupling fittings 31 and 32 for supporting the coil 30 are attached to both ends of the shaft 28, respectively. Although the coupling fittings 31 and 32 are constructed separately, they are designed to be combined with each other when assembling the device, and as illustrated in FIG. A flange 31a that is combined with the coupling fitting 32 and a hole 31b that fits into the shaft 28 are provided. The coupling fittings 31 are each attached to both ends of the shaft 28 with the flanges 31a on the outside, thereby positioning the shaft 28 in the axial direction. The coil 30 is formed in advance into a frame shape to match the magnetic gap, and is connected to the inner core 21.
The center of the side along the top and bottom surfaces of the coil 3
A pedestal 33 is glued to the center of rotation of 0, respectively.
It is attached by any other suitable method. The coil 30 as a whole is coated with a small amount of insulating varnish for the coil or adhesive resin to such an extent that the windings do not come apart. The coupling fitting 3
2 is a ring portion 32a provided on the side facing the flange 31a of the coupling fitting 31;
A cylindrical portion 32b extending outward from the coil 30 is integrally formed with the ring portion 32a and the coupling fitting 31.
It is designed to be housed in a gap surrounded by a flange 31a. The other pedestal 33 is also accommodated in the gap surrounded by the other flange 31a and the ring portion 32a, as described above. These coupling fittings 31 and 32 are screwed,
Alternatively, they are connected by adhesive or other arbitrary method. Further, the window 32c provided in the ring portion 32a is connected to the pedestal 3 accommodated therein.
Although this embodiment shows a case in which a notch is provided in the ring portion 32a, it may be a hole, and the number thereof can be selected as appropriate. Lead wire 30a of the coil 30
is adapted to be drawn out through the cylindrical portion 32b of the coupling fitting 32, but depending on the relationship with the external connection, one lead wire may be drawn out through both coupling fittings. . The covers 34 provided on both the upper and lower outer sides prevent dust from entering and also serve to protect the coil 30 inside.A hole 34a is bored in the center of the cover 34 to pass the cylindrical portion 32b of the coupling fitting 32. There is. These covers 34 are attached to the outer core or a holding member of the outer core (not shown) by an appropriate method such as screwing or gluing, but since they are mechanically completely unrelated to the internal rotating parts, they are not attached to the outer core or to the holding member of the outer core (not shown). There is no need to use a synthetic resin board, etc., and therefore, a thin transparent organic board is preferable as a material to be used because it allows internal inspection without removing it.

Note that a pen of an external mechanism (not shown), a pointer, or other recording element is connected to the coupling fitting 32. For example, in the case where only one coupling fitting 32 is connected, the other coupling fitting 32 is connected to the coupling fitting 32. 32
In such a case, the pedestal 33 may be fixed to the coupling fitting 31 on that side with an adhesive or the like. Accordingly, there is no need to provide the hole 34a of the cover 34 attached to the same side as above. Further, in this embodiment, the coupling fitting 31 is provided with a flange 31a, and the coupling fitting 32 is provided with a flange 31a.
Although a case is shown in which the ring portion 32a is provided on the side of the flange, the flange and the ring portion may be provided on either side of the coupling fitting, and as long as they are combined with each other. , its shape may be arbitrarily designed.

As explained above, the movable coil device according to this invention is configured such that one shaft 28 is rotatably supported at the center of the inner core 21, and the coil 30 is attached to this shaft 28. This eliminates the need for axis alignment adjustment, which was indispensable in conventional devices, and also eliminates the need for shaft 28
Even if, for example, a pointer or potentiometer with different inertia is attached to the upper and lower ends of the
There is almost no need to consider the twisting of the coil 30 caused by this.

Therefore, a coil frame is no longer necessary, making it possible to reduce the magnetic gap and reduce the weight of the coil. This results in an increase in magnetic flux density and a decrease in the inertia of the coil, which allows it to respond with high sensitivity to minute signal currents and to follow rapidly repeating signal currents. Now I can do it.

In addition, in this device, the bearing 29 of the shaft 28 is mounted on the internal core 21, so if a core of the same size as the conventional device is used, the overall dimension in the axial direction will be smaller, making the device thinner. It has the advantage of being tangible. Furthermore, since the main parts of the device can be assembled without the upper and lower covers 34 due to its structure, it is also excellent in mass production. In addition, a transparent thin organic material can be used for the cover 34,
Since internal inspection can be easily performed visually without disassembling the device, it is advantageous not only in terms of manufacturing but also in terms of maintenance.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of a conventional device, Figs. 2 and 3 show an embodiment of the moving coil device according to this invention, Fig. 2 is a sectional view of the main part, and Fig. 3 is a sectional view of the main part. It is an enlarged schematic sectional view seen from AA in the figure. In the figure, 21 is an inner core, 22 and 23 are outer cores, 25 is a hole, 26 and 27 are recesses, 28 is a shaft, 29 is a bearing, 30 is a coil, and 31 and 32 are coupling fittings.

Claims (1)

[Scope of utility model registration request] A movable coil device in which an annular outer core surrounds the radial outer peripheral surface of a cylindrical inner core, and a frame-shaped coil is provided that can rotate within a magnetic gap formed by both cores, The inner core has a hole drilled in the center thereof in the axial direction, a bearing arranged concentrically with the hole at the open end of the hole, and a shaft that rotates into the hole by the bearing. a movable coil device, characterized in that the coil is supported on the shaft via a coupling member;