JP2000232029A - Method for insulating coil bobbin in high-voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of mold releasing work by forming an insulating layer on a coil housed in the peripheral grooves of a coil bobbin, by solidifying synthetic resin paste injected from a nozzle hole and applied to the outer peripheral section of the bobbin while the bobbin is held and rotated. SOLUTION: While a coil bobbin 6 is held by the chucks 29a and 29b of a rotationally driving device 27 and rotated in one direction by applying a rotational force to the bobbin 6 by rotationally driving a rotating shaft 30a, synthetic resin paste is injected from the nozzle hole 32 of a coater 28 and applied to the outer peripheral section of the bobbin 6. Thereafter, the bobbin 6 is removed from the driving device 27 and set in a heating furnace and heated for a prescribed period of time to solidify the paste. Consequently, an insulating layer composed of the synthetic resin can be formed on a coil 19 housed in the peripheral grooves 16 of the bobbin 6. Since the insulating layer can be formed easily on the coil 19, no rubber jig is required and, accordingly, no troublesome mold releasing work is required and the mass-productivity of the coil bobbin can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage transformer used for a discharge device such as a lighting starter for a vehicle, an industrial discharge lamp device, and an ignition device.

[0002]

2. Description of the Related Art A discharge lamp such as a metal halide lamp used for a headlight is detachably attached to a discharge lamp socket held at a front portion of a vehicle by fitting its electrode to the socket and detaching the terminal. An electromotive force is applied. This discharge lamp is a headlight, and is applied with a high voltage of 13 kV or more, which is a dielectric breakdown voltage between electrodes. Therefore,
A voltage of about 400V is boosted by a high-voltage transformer,
A high voltage is generated at the output terminal of the secondary coil, and the high voltage is connected to the terminal of the socket so as to apply a voltage to the discharge lamp.

As a high-voltage transformer used in such a discharge device, a small-sized, high-efficiency, pot-core type high-voltage transformer having no leakage of magnetic flux has been proposed. As shown in FIG. 1, the high-voltage transformer 1 includes a pot core body 3 having a magnetic core 2 and a pot cover piece 4 attached to the pot core body 3 to form a closed magnetic pot core 5. A coil bobbin 6 made of an insulating material around which a coil 19 is wound is housed in the pot core body 3 in a state of being fitted over the magnetic core 2.

[0004]

By the way, in the coil bobbin 6 housed in the pot core body 3 as described above, the coil 19 is continuously wound around a plurality of circumferential grooves 16 formed along the circumferential direction. Although turned, an insulating layer 36 made of a synthetic resin such as urethane resin is formed on the outer periphery of the coil 19 to insulate the coil 19 in each circumferential groove 16. Conventionally, in order to form the insulating layer 36, as shown in FIG. 5, a coil bobbin 6 around which a coil 19 is wound is inserted into a rubber jig G serving as a molding die, and is inserted into a surrounding gap s. The insulating layer 36 was formed on the outer peripheral portion of the coil 19 by pouring and solidifying a synthetic resin paste. However, in the conventional method using such a rubber jig G, there has been a problem that the release operation after solidification is troublesome, requires labor and time, and the mass productivity is poor.

An object of the present invention is to provide a method of insulating a coil bobbin which does not require a releasing operation and can improve mass productivity.

[0006]

According to the present invention, there is provided a coil bobbin in which a coil is wound around a circumferential groove formed along a circumferential direction;
In a high-voltage transformer comprising a pot core body accommodating the coil bobbin and a pot lid piece attached to the pot core body, the outer periphery of the coil bobbin having a coil wound in the circumferential groove is held while rotating. A method of insulating a coil bobbin in a high-voltage transformer, characterized in that an insulating layer is formed on a coil by injecting and applying a synthetic resin paste to a part, and solidifying the paste.

As described above, an insulating layer can be formed on a coil by injecting and applying and solidifying a synthetic resin paste on an outer peripheral portion of a rotating coil bobbin, so that a conventional rubber jig can be used. It becomes unnecessary. Accordingly, it is not necessary to perform a releasing operation, and mass productivity can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
Will be described. FIG. 1 shows a high-voltage transformer 1 of a pot core type. In this high-voltage transformer 1, a closed magnetic pot core 5 is constituted by a pot core body 3 having a magnetic core portion 2 and a pot cover piece 4 attached to the pot core body 3, and a coil bobbin 6 is provided in the pot core body 3. It is stored. Here, the pot core body 3 and the pot lid piece 4
Made of ferrite, the pot core body 3
By attaching a pot lid piece 4 having the same outer diameter as that of the above, the whole has a short columnar shape.

The pot cover piece 4 of the pot core 5 has a disk shape, and has a long groove 8 in the radial direction as shown in FIG.
Are formed. Then, the slot 8 is inserted into the coil bobbin 6.
The pot cover piece 4 and the coil bobbin 6 are assembled concentrically by fitting the fitting portion 9 into the fitting portion 9 from the side.

The pot core body 3 has a structure in which a cylindrical peripheral wall 10 and a central magnetic core portion 2 are connected to each other by a bottom wall 11, and the core core portion 3 is deviated from the center. At a position, a fitting groove 13 is formed, which penetrates the magnetic core portion 2 and into which a thick portion 12 of the coil bobbin 6 described later is internally fitted. The pot core body 3 is fitted from below onto the pot lid piece 4 and the coil bobbin 6, which are integrally assembled.
The bottom wall 11 has protrusions 14a, 14a of the coil bobbin 6.
A plurality of holes 21 through which b can be inserted are formed.

The coil bobbin 6 is made of an insulating material such as a synthetic resin, and has a base tube portion 15 which is fitted to the magnetic core 2.
A plurality of circumferential grooves 16 are formed in the circumferential surface of the base cylinder portion 15 along the circumferential direction. The circumferential groove 16 is divided into a plurality of flanges 17 provided around the peripheral surface of the base cylinder portion 15.
a, 16a, 16a and intermediate grooves 16b, 16b formed on the peripheral surface of the flange piece 17, and
An annular groove 18 is formed on the lower surface of the base cylinder 15. Then, the divided grooves 16a, 16a, 16a and the intermediate groove 1
The coil 19 is continuously wound around 6b and 16b, and the annular groove 1 is formed.
The coil 20 is wound around 8. Here, the coil 20 constitutes a primary coil of the high-voltage transformer 1, and the coil 19 constitutes a secondary coil.

On the lower surface of the coil bobbin 6, as shown in FIG.
(Only one protrusion 14b is shown). The winding end, which is the low pressure end of the coil 19 as a secondary coil, is connected to the protrusion 14a. Also, the protrusion 14
The ends of a coil 20 as a primary coil loaded in the annular groove 18 are respectively connected to b and 14b. In addition, this protrusion 1
As shown in FIG. 1, when the coil bobbin 6 is housed in the pot core body 3, the projections 4 a and the projections 14 b face the outside from the hole 21 of the pot core body 3, and the winding end of the coil 19 and the coil 20 Can be connected to required electric circuits of a circuit board (not shown).

Further, the coil bobbin 6 has a thick portion 12 which is fitted inside the fitting groove 13 of the magnetic core portion 2 and protrudes above the pot cover piece 4. The thick portion 12 is provided at the center of the coil bobbin 6. The connection hole 22 is formed so as to be deviated from the connection hole.
On the upper surface side of the pot lid piece 4, a shielding plate portion 23 is connected to the thick portion 12, and the connection hole 22 is opened at an upper end of the thick portion 12. Further, a cylindrical portion 24 is formed in the shielding plate portion 23 concentrically with the connection hole 22.

In the connection hole 22, a winding start end of the coil 19 as a secondary coil is introduced from an insertion hole 25 formed in the thick portion 12, and is connected to a high-voltage end (not shown) through a connection terminal piece 26. Can supply a high voltage to the required electric circuit. This coil 19, as described above,
The winding ends are sequentially wound around the dividing groove 16a and the intermediate groove 16b constituting the sixth coil 6, and the winding end, which is the low-pressure end, is drawn out of the high-pressure transformer 1 through the hole 21.

Next, the main part of the present invention will be described. The coil bobbin 6, in which the coil 19 is wound in the circumferential groove 16 and the coil 20 is wound in the annular groove 18 as described above, has a shape of the circumferential groove 16 before the pot cover piece 4 is assembled to the fitting portion 9. An insulating layer 36 for insulating the coil 19 is formed.

As shown in FIGS. 3 and 4, the insulating layer 36 is formed by a rotation driving device 27 which holds the coil bobbin 6 so that its axis is horizontal and rotates coaxially.
An applicator 28 disposed above the outer periphery of the coil bobbin 6 is used. The rotation driving device 27 has a chuck 29
a, 29b, a pair of left and right rotation shafts 30a, 30 respectively.
b, and at least one of the rotary shafts 30a is linked to a rotary drive source to be a drive shaft. The other rotary shaft 30b is provided so as to be able to advance and retreat, so that the coil bobbin 6 can be sandwiched and detached. The chuck 2
9a is provided with a projection 37a which is fitted into the base cylindrical portion 15 of the coil bobbin 6 and is engaged with the thick portion 12, and a chuck 29b is a concave portion which is externally fitted to the cylindrical portion 24 of the shielding plate portion 23. 37b. Here, the thick portion 12 and the cylindrical portion 24 of the coil bobbin 6 are provided at positions deviated from the center of the coil bobbin 6, and the thick portion 12 and the cylindrical portion 24 are provided with the projection 37a of the chuck 29a and the chuck 29b.
By fitting each of the concave portions 37b, a rotational force around the axis can be applied to the coil bobbin 6.

On the other hand, the applicator 28 has a nozzle body 31 that covers the upper part of the coil bobbin 6, and a nozzle hole 32 that is desired on the outer periphery of the coil bobbin 6 is opened in the nozzle body 31. As shown in FIG. 3, the lower part of the nozzle hole 32 is expanded so as to correspond to the entire width of the circumferential groove 16 of the coil bobbin 6, and the left and right side walls 33, 33 are located at the outermost sides. It is provided so as to be in sliding contact with the outside of the pieces 17, 17. A supply hype 34 is connected to the nozzle hole 32, and a synthetic resin paste 35 is supplied from the supply hype 34 at an appropriate pressure. As shown in FIG. 4, the end portion 38 of the nozzle body 31 located on the rear side in the rotation direction of the coil bobbin 6 is slightly separated from the outer peripheral portion of the coil bobbin 6, and has a thickness corresponding to the gap. The paste 35 is applied.

The chuck 29 of the rotary driving device 27
a, 29b, the coil bobbin 6 is held, and the rotating shaft 3
When the coil bobbin 6 is rotated in one direction by applying rotational force to the coil bobbin 0a, the synthetic resin paste 35 is ejected from the nozzle hole 32 of the applicator 28, and the synthetic resin paste 35 is transferred to the coil bobbin 6. To the outer periphery. Here, as the synthetic resin paste 35, a paste made of a thermosetting synthetic resin such as a urethane resin, an epoxy resin, or a silicone resin can be suitably used. These synthetic resins have appropriate elasticity after solidification, and have the advantage that their materials do not deteriorate under high ambient temperature during mounting. Further, the paste 35 is adjusted to have such a viscosity that the applied state is maintained and the paste 35 does not easily flow down. When the synthetic resin paste 35 is applied to the outer peripheral portion of the coil bobbin 6, the synthetic resin paste 35 is injected from the nozzle hole 32 so that the synthetic resin paste 35 is sufficiently pressed into the deep portion of the circumferential groove 16. The pressure and the rotation speed of the rotating shaft 30a are set respectively.

After the synthetic resin paste 35 is applied to the outer peripheral portion of the coil bobbin 6, the coil bobbin 6 is removed from the rotary driving device 27, put into a heating furnace, and heated for a predetermined time to solidify the synthetic resin paste 35. Let it. Thereby, as shown in FIG. 2, the insulating layer 36 made of synthetic resin can be formed on the coil 19 in the circumferential groove 16.

Then, as shown in FIG. 1, the pot cover piece 4 is attached to the coil bobbin 6 on which the insulating layer 36 is formed, and the pot core body 3 is fitted.

In the above embodiment, the coil bobbin 6 is held and rotated so that its axis is horizontal, and the synthetic resin paste 35 is applied to the outer periphery from above. It is also possible to hold and rotate the coil bobbin 6 so that the axis becomes vertical, and apply the synthetic resin paste 35 to the outer peripheral portion from the side.

[0022]

As described above, the present invention provides a coil bobbin in which a coil is wound around a circumferential groove formed along the circumferential direction, a pot core body for accommodating the coil bobbin, and a pot core body attached to the pot core body. In a high-pressure transformer comprising a pot lid piece, while holding and rotating a coil bobbin around which a coil is wound in the circumferential groove, a synthetic resin paste is injected and applied to the outer periphery thereof, and solidified.
Since the method of insulating a coil bobbin is such that an insulating layer is formed on the coil, an insulating layer is easily formed on the coil by injecting and applying a synthetic resin paste to the outer periphery of the rotating coil bobbin and solidifying it. This eliminates the need for a conventional rubber jig, thereby eliminating the need for cumbersome mold release work and improving mass productivity.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a high-voltage transformer.

FIG. 2 is an exploded view of a high-voltage transformer.

FIG. 3 is a sectional view in the front direction showing a means for applying a synthetic resin paste.

FIG. 4 is a side sectional view showing a means for applying a synthetic resin paste.

FIG. 5 is an explanatory view showing a conventional method of forming an insulating layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-voltage transformer 3 Pot core body 4 Pot cover piece 6 Coil bobbin 16 Peripheral groove 19 Coil 35 Synthetic resin paste 36 Insulation layer

Claims (1)

[Claims] 1. A high-pressure coil comprising: a coil bobbin around which a coil is wound in a circumferential groove formed along a circumferential direction; a pot core body for accommodating the coil bobbin; and a pot lid piece attached to the pot core body. Forming an insulating layer on the coil by injecting and applying a synthetic resin paste to an outer peripheral portion of the transformer while holding and rotating a coil bobbin around which a coil is wound in the peripheral groove, and solidifying the coil bobbin; A method for insulating a coil bobbin in a high-voltage transformer.