JPH0631699Y2 - Rotary transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a rotary transformer suitable for use in a rotary magnetic head device such as a video tape recorder (VTR).

[Outline of device]

The present invention relates to a rotary transformer suitable for use in, for example, a rotary magnetic head device such as a VTR, in which a coil is wound around the outer peripheral surface of a cylindrical inner core, and the coil is wound along a drawing groove formed on the outer peripheral surface. In the pullout rotary transformer, a protrusion is formed at a predetermined portion of the extraction groove, and the winding start portion of the coil is entwined with the protrusion, so that the winding start portion of the coil can be fixed to the inner core. It is designed to be easy and reliable.

[Conventional technology]

The rotary transformer is widely used as a connecting means for transmitting a signal obtained from a video head provided on a rotary drum to a recording or reproducing circuit on a fixed side in a rotary magnetic head device of a VTR, for example.

FIG. 3 shows an application example of the conventional rotary transformer disclosed in, for example, Japanese Utility Model Laid-Open No. 59-135612. In FIG. 4, (1) is a rotor, and (2) is fixed to the rotor (1). The video head, (3), is a rotary shaft integrated with the rotor (1). A rotor side core (4) made of a magnetic material is fitted to the rotating shaft (3), and an A channel coil (5) and a B channel coil (6) are mounted on the outer peripheral surface of the rotor side core (4). Is wound. The A channel coil (5) is connected to the video head (2) through a through hole (7) formed in the flange portion of the rotor (1), for example. Similarly, the B channel coil (6) is connected to a video head (not shown) fixed to the rotor (1) at an angle different from the video head (2) by 180 °. The rotor side core (4), the A channel coil (5) and the B channel coil (6) form an inner transformer (8).

Further, (9) is a stator, and this stator (9) is attached to the fixed base by the attachment hole (10). And, inside the stator (9), a stator side core (11), which is made of a cylindrical magnetic material and has an A channel coil (not shown) and a B channel coil (12) wound around the inner surface, is fitted. Has been done. Its rotor side core (4) and stator side core (1
1) and A channel coil (5) and A channel coil and B channel coil (6) wound around the A side coil (5) and the stator side core (11) and the stator side core, which are coaxially arranged with a minute gap. B channel coil wound around (11)
By the electromagnetic coupling of each pair of (12), its video head
The signals from (2) and the video head on the opposite side are transmitted to the recording or reproducing circuit, respectively. When the number of video heads increases or decreases, the number of coil pairs wound around the rotor-side core (4) and the stator-side core (11) is correspondingly increased or decreased.

FIG. 5 shows the structure of the inner transformer (8) in the example of FIG.
In FIG. 5, winding grooves (13) and (14) and a separation groove (15) for channel separation are formed on the outer peripheral surface of the cylindrical rotor-side core (4). ) Is wound with the A channel coil (5), and the winding groove (14) is wound with the B channel coil (6). Further, a lead-out groove (16) is formed on the outer peripheral surface of the rotor side core (4) so as to be orthogonal to the winding grooves (13) and (14), and along the lead-out groove (16) for the A channel. A winding start portion (5a) and a winding end portion (5e) of the coil (5) are drawn out.

In the winding process of the coil (5) for the A channel of the inner transformer (8), a wire material having a relatively large rigidity is used as the coil (5), and the winding start portion (5a) is folded back and the drawing groove ( An inverted U-shaped folded portion (5b) was formed in 16). Then, the folded portion (5b) is connected to the rotor side core (4).
After fixing by hooking on the edge part (4a) of the wire, the wire winding jig is rotated to wind the coil (5) around the winding groove (13), and the winding end part (5e) is also wound. It was pulled out from the line groove (13).

[Problems to be solved by the device]

However, the inner transformer (8) described above has its coil (5)
The folded-back part (5b) of the edge part (4a) easily comes off,
There is an inconvenience that it takes a long time to wind the coil (5). In this case, even if the folded-back portion (5b) is temporarily fixed with an adhesive or the like, the adhesive or the like is easily peeled off when tension is applied to wind the coil (5).

Further, as shown in FIG. 6, the conventional inner transformer (8) has a coil (5) having a winding start portion (5a) at a rotor side core (4).
It is also used that the end portion (5e) is hooked to the edge portion (4c) while being hooked to the edge portion (4b).

However, in the inner transformer (8) of FIG. 6, it is necessary to deepen the winding groove (13) in order to prevent the winding start portion (5a) from coming off the edge portion (4b). However, there was an inconvenience that the characteristics as a rotary transformer deteriorated.

The present invention has been made in view of the above problems, and an object of the present invention is to propose a rotary transformer in which a coil can be easily wound around a rotor-side core (inner core) without deteriorating the characteristics of the rotary transformer.

[Means for solving problems]

In the rotary transformer according to the present invention, for example, as shown in FIG. 3, a coil (5) is wound around an outer peripheral surface of a cylindrical inner core (4), and a coil is formed along a drawing groove (16) formed on the outer peripheral surface. In the rotary transformer adapted to pull out the coil (5), a projection (18) is formed at a predetermined portion of the pullout groove (16), and the winding start portion (5a) of the coil (5) is formed on the projection (18). It is designed to entangle.

[Action]

According to the present invention, in order to wind the coil (5) around the outer peripheral surface of the inner core (4), for example, the winding start portion (5a) of the coil (5) is folded back to form an inverted U-shape. The folded portion (5c) may be formed, the folded portion (5c) may be hooked on the protrusion (18), and then the coil winding jig may be rotated to wind the coil (5). Therefore, since the folded-back portion (5c) of the coil (5) is securely fixed, the coil (5) can be easily and quickly wound around the outer periphery of the inner core (4).

Also, a protrusion (18) is provided on a predetermined portion of the pull-out groove (16) of the inner core (4).
The characteristics as a rotary transformer are not deteriorated because only the components are provided.

〔Example〕

An embodiment of the rotary transformer of the present invention will be described below with reference to FIGS. Incidentally, this FIG.
In FIG. 3, parts corresponding to those in FIGS. 4 to 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a cylindrical rotor-side core (4) of this example, and the rotor-side core (4) is made of a magnetic material such as ferrite or permalloy. On the outer peripheral surface of the rotor side core (4), two winding grooves (13), (14) for winding a coil and a separation groove (15) for channel separation are provided, and the winding grooves are The winding grooves (13), (1
Drawer groove (16) deeper than the thickness of the wire for coil by 4)
To provide. In this case, a similar drawing groove (17) may be provided at a position symmetrical to the drawing groove (16) of the rotor side core (4).

The rotor-side core (4) having such a shape can be formed by pressing magnetic powder with a mold and then cutting the magnetic powder. Further, as disclosed in JP-A-63-18609, the core on the rotor side is formed by injection molding.
(4) may be formed.

Furthermore, as shown in FIG. 1, the rotor side core (4) of this example
Two cylindrical bosses (18) and (19) are provided on the lead-out groove (16) so as to sandwich the winding groove (13). The tops (18a) and (19a) of the bosses (18) and (19) are the outermost peripheral surface (4d) of the rotor side core (4).
(See FIG. 3B) Set so that it does not project outward. Although the bosses (18) and (19) may be formed integrally with the rotor side core (4) by injection molding,
6) The cylindrical bosses (18) and (19) may be implanted in the perforations formed above and fixed with an adhesive. When the columnar bosses (18) and (19) are formed by planting like the latter, even if the material of the bosses (18) and (19) is metal other than magnetic material (brass, aluminum, etc.) Good.

A coil (5) for the A channel on the rotor side core (4) of this example
In order to wind the coil, as shown in FIG. 2, first, the winding start portion (5a) of the coil (5) having a relatively large rigidity is fixed to the boss (18).
Entangle in. Specifically, the winding start portion (5a) is folded back to form an inverted U-shaped folding portion (5c), and the folding portion (5
Hang c) around the boss (18). In this case, the distance between the side wall (16a) of the extraction groove (16) and the boss (18) is set to be slightly smaller than the wire diameter of the coil (5), and the side wall (16a) and the boss ( A part of the folded-back portion (5c) may be sandwiched between it and 18).

Next, as shown in FIG. 3A, after winding the coil (5) along the winding groove (13) from top to bottom, the winding end portion (5e) of the coil (5) is attached to the boss (19). ) And pull it out from the pull-out groove (16). Therefore, the winding start part of the coil (5)
(5a) is held between the lead-out groove (16) and the winding part of the coil (5) (see FIG. 3B).

Similarly, in order to wind the coil (6) for the B channel, a protrusion may be provided on the lead-out groove (17) of FIG. 1 and the winding start portion of the coil (6) may be entwined with this protrusion. When the lead-out groove (17) is omitted, two more protrusions are provided on the lead-out groove (16) used for pulling out the coil (5) for the A channel, and the coil ( Engage the winding start part of 6).

According to the rotary transformer of the present example, the winding start portion (5a) of the coil (5) is entwined with the boss (18) and is securely fixed, so that the winding start portion (5a) is pulled out into the extraction groove (16). It does not come off. Therefore, the rotor side core
The coil (5) can be easily wound around the winding groove (13) of (4), and there is an advantage that the time required for the winding can be shortened.

In addition, in this example, the boss is also placed near the end face of the rotor side core (4).
(19) is provided so that the winding start portion (5a) and the winding end portion (5e) of the coil (5) are separated by this boss (19), so that the coil (5) is formed in a later wiring step. There is a benefit of not getting the polarity wrong.

When a magnetic metal is used as the material for the bosses (18) and (19), the lead-out groove (16) is
It becomes a shape filled with (19), and its rotor side core
The distribution of the magnetic field generated by (4) becomes more axisymmetric. Therefore, there is an advantage that the characteristics of the rotary transformer are improved as compared with the conventional one.

In the above embodiment, the winding start portion (5a) of the coil (5) was entangled with the columnar boss (18), but instead of the columnar boss (18), a prismatic boss (18) is used. A protrusion or an inverted conical protrusion may be used. In particular, if an inverted conical projection is used, the winding start portion (5a) is more reliably fixed. Also, the boss (19) for entwining the winding end portion (5e) of the coil (5) may be omitted.

As described above, the rotary transformer of the present invention is not limited to the above-mentioned embodiment, and can be modified within the scope of the present invention.

[Effect of device]

In the rotary transformer of the present invention, as described above, the protrusion is formed on the predetermined portion of the inner lower portion, and the winding start portion of the coil having relatively high rigidity is entangled with the protrusion.
The winding start portion is securely fixed, and the coil can be easily and quickly wound around the outer peripheral surface of the inner core, and the characteristics are not deteriorated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a rotor side core of an embodiment of the present invention, FIG. 2 is a diagram for explaining a method of winding a coil around the rotor side core of FIG. 1, and FIG. A front view of the inner transformer of the embodiment, FIG. 3B is a bottom view of the upper half thereof, FIG. 4 is an exploded perspective view showing an application example of a conventional rotary transformer, and FIG. 5A is an inner transformer of the FIG. FIG. 5B is a bottom view of the upper half, and FIG. 6 is a front view of another example of the conventional inner transformer. (4) is the rotor side core, (5) is the coil for A channel, (5
(a) is a winding start portion of the coil (5), (13) and (14) are winding grooves, (16) is a drawing groove, and (18) and (19) are cylindrical bosses, respectively.

Claims (1)

[Scope of utility model registration request] 1. A rotary transformer in which a coil is wound around an outer peripheral surface of a cylindrical inner core, and the coil is drawn out along a drawing groove formed on the outer peripheral surface. A protrusion is provided at a predetermined portion of the drawing groove. And a winding start portion of the coil is entwined with the protrusion.