JPS6120723Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mounting structure for a rotary transformer used in a rotating head drum of a VTR, etc.

A rotating magnetic head drum of a video tape recorder (VTR) is equipped with a rotary transformer for transmitting recording signals and reproduction signals between the rotating drum and the fixed drum without contact. FIG. 1 is a sectional view of a transformer core 1 conventionally used in such a rotary transformer. Note that the first
When the transformer core shown in the figure is provided on the fixed drum side, the same core is provided oppositely on the rotating drum side to form a rotary transformer.

The rotary transformer core 1 shown in FIG. 1 is made of, for example, ferrite material and molded into an annular shape, and its surface has two concentric grooves 2 and 3 for installing coils.
is formed. These coil mounting grooves 2 and 3
Each of the toroidal coils for the A head and the B head is attached. A ring-shaped collar 4 is provided around the outer periphery of the core 1 for fixing the core 1 to the surface of a rotating drum or a stationary drum. The core 1 is fixed to the drum by holding this flange part with a ring-shaped fixing metal fitting and screwing a screw into the metal fitting into the drum surface.

The rotary transformer core shown in Fig. 1 is equipped with a flange 4 for attachment, so the difference in wall thickness between the surface portion (opposing surface) of the core 1 and the flange 4 makes it difficult to press during press molding. The pressure becomes uneven, which tends to cause warping and distortion during sintering. For this reason, the gap in the core 1 between the fixed drum and the rotating drum changes depending on the rotation angle, resulting in distortion in the transmission characteristics of the rotary transformer. Furthermore, due to the unevenness of the press pressure, the edge 7 on the outer periphery of the opposing surface of the core 1 is likely to be chipped, resulting in a reduction in transmission efficiency.

The present invention was developed in view of the above-mentioned problems, and the purpose is to make it possible to attach the core without using the collar, thereby minimizing the occurrence of warping or chipping during core firing. There is.

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

FIG. 2 is a plan view of the rotary transformer core 1 according to the present invention, and FIG. 3 is a side view. This core 1
is molded into an almost perfect annular shape and does not have the collar 4 as shown in FIG. Coil mounting grooves 2 and 3 are formed concentrically on the surface of the core 1, and a drive shaft insertion hole 5 is formed in the center of the core 1. Furthermore, a pair of lead wire extraction grooves 6a, 6b are formed in the radial direction on the surface of the core 1, and the lead wires of two annular coils (not shown) for the A head and B head are inserted into these grooves 6a, 6b. pulled out along.

After the core 1 shown in FIGS. 2 and 3 is positioned at the center of a rotating drum or a stationary drum, it is also fixed with a fixture 8 shown in FIG. 4. This ring-shaped fixture 8 has mounting legs 9a, 9b, and 9c spaced at 120° intervals, and has mounting legs 9a, 9b, and 9c on the inner peripheral edge.
Presser claws 10a and 10b are provided with an interval of 180°. On the other hand, the above-mentioned presser claws 10 are attached to the outer peripheral edge of each lead wire pull-out groove 6a, 6b of the core 1 in FIG.
Engagement grooves 11a and 11b are formed to engage with the grooves a and 10b.

FIG. 5 is a plan view of the state in which the core 1 is fixed, and FIG. 6 is a partial sectional view taken in direction A in FIG. Note that the coils are omitted in FIGS. 5 and 6.

The core 1, which is positioned at the center of the stationary drum or the rotating drum and temporarily fixed with adhesive, is aligned with the holding claws 10a, 10b of the fixing metal fitting 8 and the engaging grooves 11a, 11b of the core 1, as shown in FIG. By aligning and screwing the mounting legs 9a, 9b, and 9c to the drum base 12 as shown in FIG.
It is held down and securely fixed by the holding claws 10a and 10b.

Next, FIG. 7 shows a fifth example showing a modification of the above-mentioned embodiment.
It is a top view similar to the figure. In this embodiment, the core 1 is not particularly provided with the engaging grooves 11a, 11b as shown in FIG. 2, and the core 1 is fixed using the lead wire pulling grooves 6a, 6b. Therefore, the presser claws 10a, 10b of the fixing metal fitting 8 fit into the groove 6.
It is formed thinner than a and 6b.

According to the embodiment shown in FIGS. 2 to 7 described above, since the collar portion 4 shown in FIG. 1 for fixing the core 1 is not required, the outer diameter of the entire core can be reduced, and Also, the wall thickness is uniform. Therefore, warpage and distortion caused by shrinkage during sintering can be reduced, and an extremely precise rotary transformer can be constructed. In addition, chipping of the edges on the outer periphery of the facing surface is less likely to occur. Also, since the engaging grooves 11a and 11b are provided in the lead wire pulling grooves 6a and 6b, or the lead wire pulling grooves are used as engaging grooves, the opposing area of the transformer core is prevented from decreasing as much as possible. be able to. Therefore, no significant deterioration occurs in the transmission characteristics of the transformer.

Furthermore, since there is less warping and distortion, it is possible to make it more flat, and the effective opposing area is small, so the outer diameter can be made smaller, the overall size can be made smaller, and it can be produced at lower cost. Furthermore, by enlarging the opposing area by the amount of the flange portion 4 shown in FIG. 1, a multi-channel rotary transformer can be constructed with the same outer diameter as the conventional one.

In each of the above embodiments, a two-channel (A head, B head) rotary transformer was described, but a multi-channel (3 channel, 4 channel, etc.) transformer for a monitor head, an auxiliary head for still reproduction, etc. The present invention can also be applied in the case of

As described above, the present invention forms a radial lead wire pull-out groove extending from the center to the outer circumference on the surface of the annular transformer core constituting the rotary transformer, and a presser foot that engages with a recess connected to the outer periphery of the core of this pull-out groove. The transformer core is also fixed using an annular fixing fitting having claws. Therefore, there is no need to provide a fixed collar around the outer circumference of the transformer core, so it is possible to create an annular core with a small outer diameter and uniform inner thickness, which prevents warping and distortion caused by shrinkage during sintering. It is possible to manufacture an extremely precise transformer core.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the core of a conventional rotary transformer, Fig. 2 is a plan view of the transformer core of the embodiment of the present invention, Fig. 3 is a side view of Fig. 2, and Fig. 4 is a fixed view. FIG. 5 is a plan view of the metal fittings, FIG. 5 is a plan view with the core attached, FIG. 6 is a partial sectional view taken in direction A in FIG. 5, and FIG. 7 is similar to FIG. 5 showing a modification of the present invention. FIG. In addition, in the symbols used in the drawings, 1...
...Transformer core, 2, 3...Groove, 6a, 6b...
Lead wire pull-out groove, 8...Fixing bracket, 10a,
10b...presser claws, 11a, 11b...engaging grooves.

Claims (1)

[Scope of utility model registration request] In a mounting structure for a rotary transformer for transmitting signals between a rotating part and a fixed part, a lead wire extraction groove is formed on the surface of an annular transformer core constituting the rotary transformer, extending radially through the center to the outer periphery. and a mounting structure for a rotary transformer, wherein the transformer core is fixed to the rotating part or the fixed part using an annular fixing metal fitting having a presser claw that engages with a recess connected to the outer periphery of the core of the pull-out groove.