JPH0429306A - Rotary transformer - Google Patents

Abstract

PURPOSE:To eliminate troublesome work of groove processing and to simplify a manufacture process by integrally forming a winding groove and a lead-out groove to lead out a terminal of a coil arranged therein through injection molding. CONSTITUTION:A concentric winding groove 3 and a lead-out groove 5 to lead out a terminal of a coil 2 arranged therein are integrally formed on one side by injection molding. Therefore, a process such as troublesome groove processing can be simplified. Thereby, a manufacture process is simplified, producibility is improved, distortion, deformation, etc., are reduced since burning is not carried out after injection molding, grinding operation after injection molding is reduced, dimensional accuracy is improved, a distance between opposite magnetic cores is reduced, and properties as a rotary transformer is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary transformer used in a rotating magnetic hand device such as a video tape recorder or a digital audio tape recorder.

[Summary of the invention]

The present invention provides a rotary transformer for transmitting and receiving signals between a circuit provided on a rotating side and a circuit provided on a fixed side, including a winding groove and a lead-out groove for leading out the terminal of a coil disposed in the winding groove. By integrally molding them by injection molding, the manufacturing process can be simplified and the rotary transformer can be provided with high precision.

(Prior Art) A rotary transformer is a connection for transmitting a signal obtained from a rotating magnetic head provided on the rotating side to a fixed side circuit in a rotating magnetic head device such as a video tape recorder or a digital audio recorder. It is widely used as a means.

Conventionally, as this type of rotary transformer, for example,
As shown in FIG. 6, a pair of cylindrical magnetic cores (51) and (52) having different outer diameters are arranged coaxially and facing each other in close proximity to each other inside and outside. A so-called vertical rotary transformer is known.

The rotary transformer is composed of a magnetic core (51), ie, a stator, attached to the stationary side, and a magnetic core (52), ie, the rotor, attached to the rotating side, and the opposing surfaces of these magnetic cores (51) and (52) concentric winding grooves (53) provided in each.

Annular coils (55) and (56) are arranged inside (54). And the rotary transformer is
Koinosen 55 of these magnetic cores (51) and (52)
), (56) connects, for example, a rotating magnetic head connected to one magnetic core (51) and, for example, a reproducing circuit connected to the other magnetic core (52), thereby allowing video signals and digital signals to be connected. It is designed to transmit audio signals, etc.

By the way, in order to manufacture the above-mentioned rotary transformer, magnetic powder such as ferrite is pressed using a mold or injection molded to form a cylindrical core, which is then fired at a high temperature, and then the winding grooves are formed into a cylindrical core. (53), (54
) and pull-out grooves (not shown) for leading out the terminals of the coils (55) and (56), etc. are made by grinding.

The reason for grinding the winding grooves (53), (54) and pull-out grooves after firing is to prevent the core from becoming distorted or deformed due to differences in heat conduction during firing. If the winding grooves (53), (54) and pull-out grooves are integrally formed by injection molding and then fired, the dimensions of the winding grooves (53), (54) and pull-out grooves will change significantly due to firing, and the dimensions will not meet the specified dimensions. It will not be possible to secure the Therefore, these winding grooves (53) (54) and the pull-out grooves must be finished by grinding after firing.
Further, since the winding grooves (53), (54) and the pull-out grooves undergo a large amount of deformation due to firing and require a considerable amount of grinding allowance, it is preferable to process them after firing.

In addition, in the above rotary transformer, each winding groove (
In order to connect the terminals of the coils (55) and (56) led out through the lead-out grooves from 53) and (54) to the device side, resin was molded on the negative side of the magnetic cores (51) and (52). Mold part (57), (5
B), and the coil (55) is attached to the terminals (59) and (60) attached to the molded parts (57) and (58).
, (56) is attached to the terminal for connection.

In addition, as a rotary transformer using molding technology, for example, as disclosed in JP-A-62-128507, a coil having an annular shape is molded and this molded body is fitted into a winding groove. A rotary transformer designed to be installed together has been proposed.

However, the mold parts (57) and (58) are
It is necessary to manufacture it in a separate process from the manufacturing process of the magnetic cores (51) and (52). This increases the number of manufacturing steps and reduces productivity. In addition, this mold part (57), (
58) to the magnetic cores (51) and (52), which also requires work. On the other hand, in the rotary transformer disclosed in the above-mentioned publication, the molded body is also a separate member, which is disadvantageous in terms of improving productivity.

[Problems to be Solved by the Invention] As described above, since the above-mentioned rotary transformer requires firing, the winding grooves and the lead-out grooves have to be processed after firing, which is a lot of troublesome work. Moreover, there are many manufacturing steps, and it is not possible to improve productivity.

Furthermore, in the rotary transformer, since the mold body is manufactured in a separate process from the magnetic core, the process of manufacturing the mold body is time consuming, making it impossible to expect an improvement in productivity.

Therefore, the present invention has been devised in view of the conventional situation, and an object thereof is to provide a rotary transformer that eliminates the need for baking after injection molding and enables highly accurate rotary transformers to be manufactured with high productivity. That is.

(Means for Solving the Problems) The rotary transformer according to the present invention is constructed to achieve the above-mentioned object, and includes a concentric winding groove on the side surface and a winding groove disposed in the winding groove. The winding groove is provided with a magnetic core integrally molded by injection molding, and the coil is disposed in the winding groove.

In the present invention, the winding groove and the lead-out groove for leading out the terminal of the coil disposed in the winding groove are integrally molded by injection molding, and then used as a magnetic core without firing. Therefore, since there is a need to omit firing for such a molding material, for example, a material prepared by kneading a fired spinel magnetic powder with a polymeric material is used.

As the magnetic powder, for example, Mn that has been sintered into spinel
-Zn ferrite, Ni-Zn ferrite, Ni-Cu
-Metal oxide powders such as Zn, metal powders such as iron and nickel, or metal alloy powders such as carbonyl iron and sendust can be used, and these may be one type, or
Two or more types may be used as a mixture, and among these, metal oxide powders such as Mn-Zn ferrite and Ni-Zn ferrite are particularly suitable.

On the other hand, thermoplastic resin is suitable as the polymer material.

Such thermoplastic resins include, for example, polypropylene,
Polyethylene, polyamide, polycarbonate, polybutadiene terephthalate, polyphenylene sulfide, polystyrene, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, polyethylene terephthalate, polymethyl methacrylate, polyacetal, polytetrafluoroethylene, polyvinyl acetate, polyvinyl butyral, Vinyl chloride vinyl acetate copolymer, polychlorotrifluoroethylene, diallyl phthalate resin, polyisobutylene, polyurethane, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, styrene butadiene, thermotropic liquid crystal resin, etc. Can be mentioned.

Further, it is preferable to mix a lubricant and a plasticizer into the kneaded product made of these materials in order to improve fluidity during molding.

Examples of lubricants include cadmium stearate, cadmium laurate, cadmium ricinoleate, cadmium naphthenate, cadmium 2-ethylhexoate, barium stearate, barium laurate, barium ricinoleate, barium naphthenate, and 2-ethylhexoin. barium acid, calcium stearate, calcium laurate, calcium ricinoleate, zinc stearate,
Examples include metal soaps such as zinc laurate, zinc ricinoleate, zinc 2-ethylhexoate, lead stearate, dibasic lead stearate, lead naphthenate, tin stearate, and magnesium stearate. Among these, barium stearate, calcium stearate, zinc stearate, lead stearate, and magnesium stearate are more preferred.

As a binder, dibutyl phthalate, dioctyl phthalate, diisodecyl phthalate, butyl lauryl phthalate,
Examples include phthalic acid lubricants such as ditridecyl phthalate and butylbenzyl phthalate, and phosphoric acid lubricants such as tricresyl phosphate and trioctyl phosphate.

Further, a compressing agent may be used for the purpose of improving the adhesion between the magnetic powder and the thermoplastic resin.

Suitable examples of the coupling agent include titanate coupling agents and silane coupling agents.

In the magnetic core obtained by injection molding, the magnetic powder is pressurized evenly in all directions within the mold, so there is little residual stress, and the distribution of packing density is homogeneous, preventing the occurrence of cracks. is suppressed. Furthermore, injection molding is a molding method that allows the production of very fine shapes, and is therefore suitable for molding cores with complex shapes.

[Effect]

In the rotary transformer according to the present invention, the winding groove and the pull-out groove for leading out the end of the coil disposed in the winding groove are integrally molded by injection molding.
It has a structure that simplifies the manufacturing process by eliminating the need for troublesome work such as groove machining.

〔Example〕

Hereinafter, specific examples to which the present invention is applied will be described.

This embodiment is an example in which the present invention is applied to a so-called vertical rotary transformer in which cylindrical magnetic cores having different outer diameters are disposed coaxially and facing each other in close proximity to the inside and outside. In this embodiment, a magnetic core disposed inside of these magnetic cores will be described as an example.

The magnetic core (1) serves as a stator attached to the fixed side of the drum, for example, and as shown in FIGS. 1 and 2, a coil (2) is attached to the cylindrical outer peripheral surface (1a).
The winding groove (3) in which the short ring (6) is disposed, the short ring groove (4) in which the short ring (6) is disposed, and the terminal (2) of the coil (2).
It has a lead-out groove (5) for leading out a) and (2b).

The winding groove (3) is for arranging a coil (2) made of, for example, an annular shape in advance or simply made of wire, and is provided on the outer circumferential surface (1a) of the magnetic core (1) with a rough cross section. It is formed in an annular shape as a U-shaped groove. In addition,
The winding grooves (3) are provided in the same number as the required number of channels at predetermined intervals along the axial direction of the magnetic core (1).

On the other hand, the short ring groove (4) is a short ring made of an insulating wire material, etc., which prevents mutual interference noise between the coils (2) respectively arranged in the winding groove (3) and changes in inductance. (6), and are provided between the winding grooves (3). This short ring groove (4) is also similar to the previous winding groove (3).
The groove is formed in an annular shape with a substantially U-shaped cross section.

The above-mentioned lead-out groove (5) is connected to each of the above-mentioned winding grooves (3).
The terminals (2a) and (2b) of the coil (2) arranged in
) to the drum side, and is provided along the axial direction from a part of each of these winding grooves (3) to one end edge side of the magnetic core (1) (to the side when attached to the drum). It is being That is, the above-mentioned lead-out groove (5) is connected to each of the above-mentioned winding grooves (
3) is formed as a vertical groove deeper than the bottom of the -t = cotton wire groove 3) along the axial direction of the magnetic core (1) to a portion reaching one end edge side. Note that this pull-out groove (5
) is formed up to a portion extending to a later-described flange portion (7) provided at one end edge in the axial direction of the cylindrical magnetic core (1).

In addition, the magnetic core (1) has a cylindrical outer circumferential surface (1a) formed at one end edge in the axial direction to protrude outward from the cylindrical outer circumferential surface (1a) in order to ensure reliable attachment to the drum. An annular top portion (7) is provided. This brim (
7) is the terminal (2a) of the coil (2) that is guided and led out in the lead-out groove (5).

Terminals (8a) and (8b) are provided for connecting (2b) to wiring provided on the device side. These terminals (8a) and (8b) are installed in the vicinity of the outer periphery of the flange (7) in the thickness direction, and their tips protrude from the surface (7a) when attached to the drum. ing.

The collar portion (7) also has a surface (7a) for attaching the terminals (2a) and (2b) of the coil (2) to the drum.
Through holes (9a) and (9b) for leading out to the side are provided at positions close to the terminals (8a) and (8b). Therefore, the terminal (2a) of the coil (2),
(2b) are the respective through holes (9a) and (9b
), the attachment to the drum is led out to the surface (7a) side, and the attachment to the drum is guided through the terminal (8a) on the surface (7a) side.
) and (8b). In addition,
Terminals (2a) (2b) and terminals (8) of these coils (2)
Connections with a) and (8b) are made by soldering or the like.

Further, the flange portion (7) is provided with holes (10) for fixing the magnetic core (1) to the drum with bolts in order to simplify the work and improve reliability. There is. For this installation, the hole (10) is also the through hole (9a).
, (9b), it is formed to penetrate in the thickness direction of the collar (7).

By the way, in order to produce the magnetic core (1) having the structure described above, it is carried out as follows.

First, an injection molding material made by kneading a binder with ferrite, etc., which has been fired to form spinel, is poured into a mold and injection molding is performed.

At this time, the winding groove (3), the short ring groove (4), the pull-out groove (5), the collar (7), and the through hole (9a)
(9b) For installation, the holes (10) are simultaneously molded in one piece. Further, the terminals (8a) (8b) are arranged in advance in the mold so that they are provided at predetermined positions on the collar (7) during molding.

Injection molding is a method that allows the production of very fine and complex shapes, and therefore complex shapes such as those described above can be easily produced. Injection molding is particularly effective for forming vertical grooves such as the pull-out grooves (5) in the magnetic core (1) having a flange-like tail (7) as in this example. Therefore, it is possible to simplify the manufacturing process such as groove machining and hole machining, and to greatly improve productivity.

Next, the coil (2) is arranged in the winding groove (3) without firing the magnetic core (1) after injection molding, and the short ring (6) is arranged in the short ring groove (4). .

Terminals (2a) and (2b) of the coil (2)
) is guided along the pull-out groove (5), and its tips are inserted into the through holes (9a) and (9b) provided in the collar (7). It is guided to the (7a) side and connected to the terminals (8a) and (8b) for soldering.

Next, after completing these winding processes and lead processes, the outer diameter dimension R and height H of the magnetic core (1) are ground to predetermined values.

As a result, the outer circumferential surface (1a) and both ends in the height direction of the magnetic core (1) are ground to a predetermined outer diameter and height. At this time, the outer peripheral surface (la
), the coil (2) itself disposed in the winding groove (3) is also ground, and as shown in FIG. 3, the outer peripheral surface (1a) of the magnetic core (1) and the coil ( 2), the ground surface of the coil (2) becomes the road surface.

Therefore, the facing distance between the magnetic core (1) and the other magnetic core (11) disposed opposite to each other is shortened, and the characteristics as a rotary transformer are improved.

In addition, in this example, since the magnetic core (1) is not fired after injection molding, the amount of distortion and deformation occurring in the magnetic core (1) is small, and it is possible to grind accurately with a small amount of grinding allowance. . Therefore, the outer diameter dimension R and height H of the magnetic core (1) can be made highly accurate, and the grinding operation time can be significantly shortened.

Incidentally, the other magnetic core (11) disposed opposite to the outside is also produced by integrally molding the winding groove, short ring groove, pull-out groove, etc. by injection molding, in the same way as the above-mentioned magnetic core (1). . Of course, this magnetic core (11) has a winding groove (
A winding groove and a short ring groove are respectively provided at positions facing the soyot ring groove (4) and the like.

The magnetic cores (1) and (11) produced as described above are
As shown in Figure 4, the magnetic core (1) provided inside
For example, the magnetic core (11) disposed on the outside is attached to the lower drum (12) on the fixed side in a fixed position, and the magnetic core (11) disposed on the outside is attached to the upper drum (13) on the rotating side in a fixed position.

The lower drum (12) of the magnetic core (1) located inside the above
), as shown in Figure 5, the bolt (14) provided on the collar (7) is inserted through the hole (10).
It is fixed by fastening it to the 7-gear part (15) provided on the lower drum (12). Therefore, the magnetic core (1) can be easily attached to the lower drum (12), and the attachment condition is stable. On the other hand, the magnetic core (1) disposed on the outside is similarly attached to the striped part (not shown) provided on the upper drum (13) on the collar part by fastening a bolt inserted through the hole. Installed in.

As a result, these magnetic cores (1) and (11) are arranged facing each other with a minute gap on the rotating side and the stationary side, respectively, and the magnetic core (1) attached to the upper drum (13) on the rotating side (
11) and each coil of the magnetic core (1) attached to the fixed side, video signals, digital audio signals, etc. are transmitted.

In the rotary transformer configured in this way,
The outer diameter dimensions and heights of the magnetic cores (1) and (11) are accurately determined, and the drums (12) and (13) are precisely determined.
), so these magnetic cores (]), (
]1) The distance between opposing faces becomes extremely small, and improvement in characteristics can be expected.

As described above, in this embodiment, cylindrical magnetic cores having different outer diameters are disposed close to each other on the inside and outside and facing each other.

Although the present invention has been applied to so-called vertical rotary transformers, the present invention can also be applied to so-called flat rotary transformers in which substantially disk-shaped magnetic cores are arranged facing each other with a small gap.

〔Effect of the invention〕

As is clear from the above description, in the rotary transformer of the present invention, the winding groove and the lead-out groove for leading out the end of the coil disposed in the winding groove are integrally formed by injection molding. This structure greatly simplifies the troublesome processes such as groove machining.

Therefore, according to the rotary transformer of the present invention, the manufacturing process can be greatly simplified and productivity can be improved.

Furthermore, in the rotary transformer according to the present invention,
Since no firing is performed after injection molding, there is extremely little distortion or deformation, and it is possible to shorten the grinding work after injection molding. Furthermore, improvement in dimensional accuracy can be expected, the distance between opposing magnetic cores can be shortened, and the characteristics as a rotary transformer can be improved.

Furthermore, in the rotary transformer according to the present invention,
The lead-out groove that guides the end of the coil placed in the winding groove can also be integrally molded by injection molding, so there is no need to create a separate mold body as in the past, and the manufacturing process can be reduced. can.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view showing one magnetic core (stator) constituting a rotary transformer to which the present invention is applied;
The figure is a plan view thereof, and FIG. 3 is an enlarged sectional view of a main part showing the winding groove. FIG. 4 is a sectional view showing how the rotary transformer is attached to the drum, and FIG. 5 is an enlarged sectional view of a main part showing how one magnetic core (stator) is attached to the lower drum. FIG. 6 is an enlarged sectional view showing an example of a conventional rotary transformer. 1... Magnetic core 2... Coil 2a, 2b... Coil terminal 3... Winding groove 4 ・ ・ 5 ・ ・ 7 ・ ・ 12 ・ 13 ・ ・Shigot ring groove・drawing groove・flange portion・・Lower drum...Upper drum Patent applicant Sony Corporation representative Patent attorney Akira Koike (and two others) Figure 4

Claims (1)

[Claims] A magnetic core is provided with a concentric winding groove on one side and a pull-out groove for leading out the end of the coil disposed in the winding groove, which are integrally molded by injection molding, and the coil is disposed in the winding groove. A rotary transformer is installed.