JPH0525074Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a rotary head device suitable for application to various VTRs and the like.

[Summary of the idea]

This invention relates to a rotating head device suitable for application to various VTRs, etc., and in particular, by using a bobbinless coil as a means for detecting the rotational position or rotational frequency of a rotating drum, this type of detection means can be miniaturized. At the same time, it can be constructed at low cost.

[Conventional technology]

A rotary head device used in various VTRs is generally constructed as shown in FIG.

In FIG. 3, reference numeral 1 indicates a rotating shaft, to which a lower drum (fixed drum) 2 is attached via a bearing 4, and an upper drum (rotating drum) 3 is attached to the upper end of the rotating shaft 1. This rotating shaft 1
It is attached so that it rotates together with the

A detection means 5 for detecting the rotational position of the upper drum 3 or the rotational frequency of the upper drum 3 is provided at a predetermined position inside the lower drum 2 . This detection means 5 is configured as a PG coil as is well known, and is connected to the upper and lower flanges 6A and 6B of the bobbin 6.
A detection coil 7 is wound with a predetermined number of turns between the bobbin 6 and an iron core 8 as shown in the figure.
has been inserted.

An insertion portion 6C is formed on the lower flange 6B side,
This insertion portion 6C is a through hole 2 formed in the lower drum 2.
A, for example, is press-fitted and fixed to the lower drum 2. Connection terminals 7A and 7B of the coil 7 are connected to the lower drum 2.
It is electrically connected by solder or the like to a conductive layer of a board (printed board) 9 fixed to the board.

As shown in the figure, the upper end of the iron core 8 is provided so that a part thereof protrudes upward, and this tip part faces the permanent magnet 11 attached to the mounting board 12 of the upper drum 3 at a predetermined distance. Its mounting position is selected.

With this configuration, in this example, the upper drum 3 is rotated once every rotation of the upper drum 3.
Since the permanent magnet 11 provided on the upper drum 3 crosses the detection means 5, a detection pulse is output from the coil 7 each time the permanent magnet 11 passes.
The rotational position of can be determined from the phase of this detection pulse.

When the detection means 5 is configured as a means for detecting the rotational speed of the upper drum 3, a plurality of permanent magnets 11 are attached to the upper drum 3 at predetermined intervals.

A rotary head H attached to a base 13 is fixedly attached to a predetermined position of the upper drum 3 so as to slightly protrude from the outer peripheral surface of the upper drum 3, as shown in the figure.

[Problem that the invention attempts to solve]

By the way, when the means 5 for detecting the rotational position of the upper drum 3 is constituted by the coil 7, the bobbin 6, and the iron core 8, the following problems arise.

That is, since the bobbin 6 is relatively expensive among the components of the detection means 5, the unit price of the detection means 5 is high, and the bobbin 6 is relatively expensive.
Since the coil 7 is wound around the detection means 5, there is a drawback that the detection means 5 itself cannot be miniaturized.

Therefore, this invention solves the above-mentioned conventional problems and proposes a rotary head device that is equipped with a small and inexpensive detection means.

[Means for solving problems]

In order to solve the above problems, this idea
As shown in FIG. 1, the detection means 5 is constructed using a bobbinless coil 15. The bobbinless coil 15 is fixed to the substrate 9.

[Effect]

According to this configuration, since the detection means 5 can be configured without using a bobbin, the configuration of the detection means 5 is simplified, and since it is a bobbinless coil, it is inexpensive.

〔Example〕

FIG. 1 is a sectional view showing an example of a rotary head device according to the present invention, and the same parts as in FIG. 3 are given the same reference numerals and their explanation will be omitted.

In this invention, as shown in the figure, an iron core 8 is inserted into the inner diameter part 15A of a bobbinless coil 15 fixed to a substrate 9, and a permanent magnet 11 is attached to the upper drum 3 facing the iron core 8. PG detection means 5 is constructed.

Figure 2 shows an example of the assembly process of this detection means 5. As shown in figure A, a self-welding wire with a diameter of about 0.2 to 0.03 mm is used as the PG coil, and this is attached to a winding jig. The wire is wound to a predetermined size using a wire, and in that state the wire is fixed using heat or solvent. When the coil is fixed, the lead wires 15B and 15C, which are the starting and ending ends of the coil, are drawn out to one side.

Next, the winding jig is removed, and the bobbinless coil 15 is fixed to a predetermined position on the substrate 9. That is,
As shown in FIG. is fixed to the substrate 9 using adhesive or other means. After that, the lead wires 15B and 15C of the bobbinless coil 15 are connected to the board 9.
The two are electrically connected by soldering to a conductive layer formed on the conductive layer.

After fixing the bobbinless coil 15 to the substrate 9, the process moves to step C in the same figure. An iron core 8 is fixed to a predetermined position of the lower drum 2 by press-fitting or the like as shown in the figure, and in a state where this iron core 8 is positioned so as to pass through the inner diameter portion 15A of the bobbinless coil 15, The substrate 9 is fixed to the lower drum 2 by screws or the like. This completes the centering of the iron core 8 and the bobbinless coil 15.

Note that the tip of the iron core 8 is as shown in FIG.
The length of the iron core 8 is selected so that a part of it protrudes.

On the other hand, a rod-shaped permanent magnet 11 is attached and fixed to the upper drum 3 facing the iron core 8, as shown in FIG. In this case, since the detection accuracy of the detection means 5 is determined by the coincidence of the axes of the iron core 8 and the permanent magnet 11, the fixed position of the bobbinless coil 15 may be slightly shifted from the iron core 8.

In this way, the bobbinless coil detection means 5 is constructed through the steps shown in FIGS. 2A to 2C.

Although this invention has been applied to the detection means for detecting PG pulses in the above description, it goes without saying that it can also be used as a detection means for detecting the rotational speed of the upper drum 3.

As the coil, a coil wire other than a self-fusion wire may be used.

[Effect of idea]

As explained above, according to this invention, a bobbinless coil is used and the bobbinless coil is fixed to a board fixed to a fixed drum to constitute the detection means, so there is no need to use a bobbin. As a result, the structure of the detecting means is simplified, and the detecting means can be made smaller than before and can be constructed at low cost.

Furthermore, by adopting the configuration of this invention, the iron core is fixed directly to the fixed drum, so the iron core is securely fixed, and the board does not need to support the iron core, so the strength burden on the board is lightened. It also has the effect of

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of essential parts of an example of a rotary head device according to this invention, FIG. 2 is an assembly process diagram of a detection means, and FIG. 3 is a vertical cross-sectional view of an example of a conventional rotary head device. . 1 is the rotating shaft, 2 is the lower drum, 3 is the upper drum, 5
1 is a detection means, 15 is a bobbinless coil, 11 is a permanent magnet, and 9 is a substrate.

Claims (1)

[Claim for Utility Model Registration] An iron core is fixed to a mounting hole formed at a predetermined position of a fixed drum, and a substrate fixed to the fixed drum has a predetermined inner diameter and a predetermined number of turns. A cylindrical bobbinless coil is fixed, and the iron core is inserted into the inner diameter of the bobbinless coil and the through hole of the substrate corresponding to the inner diameter to adjust the rotational position of the rotating drum or the rotational frequency of the rotating drum. A rotary head device comprising a detection means.