JP2000173840A - Coil unit and transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer which is lessened in both number of component parts and assembly man-hours, easily assembled, and enhanced in current carrying capacity. SOLUTION: A transformer T is equipped with a pair of PQ cores 1 and 2, where primary coil units 3 and 4 and a secondary coil unit 5 whose outer surface is covered with an insulating material are pinched between the PQ cores 1 and 2. The secondary coil unit 5 is pinched between the primary coil units 3 and 4, and sealed up with molding resin integrally with insulating material spacers between the two secondary coils of copper plate through an injection molding method. The inner diameter of the primary coil and the outer diameter of the secondary coil are set equal to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coil unit and a transformer, and more particularly, to a coil unit and a transformer suitable for use in a DC power supply circuit.

[0002]

2. Description of the Related Art For example, FIGS.
Is disclosed in Japanese Patent Application Laid-Open No. 7-235426.

In this transformer, a pair of primary windings 23 and 24, a pair of secondary windings 25 and 26, an insulating member 27, and a pair of divided primary windings 23 and 24 are provided between a pair of cores 21 and 22 having protrusions 21A and 22A. Spacers 28 to 31 are sandwiched.

The assembling of the transformer is performed by assembling a secondary winding 26, a spacer 31, a primary winding 24, and a spacer 3 on an insulating member 27.
0, a secondary winding 25, a spacer 29, a primary winding 23, and a spacer 28 in this order.
22 is completed. The two divided secondary windings 25 and 26 are connected so that the terminals 25A and 26B and the terminals 25B and 26A are externally parallel.

Japanese Patent Application Laid-Open No. 7-161552 discloses that
A coil made of copper plate insulated with polyimide coating,
A transformer is disclosed in which a required number of layers are stacked and combined with a pair of ferrite cores.

[0006]

However, as described above, in order to ensure insulation between the primary windings 23, 24 and the secondary windings 25, 26, the insulating member 27 and the spacers 28 to 31 are used. In the method of forming a transformer by incorporating the components, there is a problem that the number of parts is increased, the number of assembling steps is increased, and the assembling is troublesome. Also, JP-A-7-16
In the transformer disclosed in Japanese Patent No. 1552, it is not necessary to arrange an insulating material between the coils when assembling the transformer.
However, in a transformer to which a high voltage is applied, it is difficult to obtain a desired dielectric strength with a film thickness formed by coating.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reduce the number of transformer components and the number of assembling steps, simplify the assembling and reduce the size of the transformer.
Moreover, it is an object of the present invention to provide a transformer to which a high voltage can be applied and a coil unit suitable for using the transformer.

[0008]

In order to achieve the above object, an invention according to claim 1 is a coil unit for a transformer, wherein two coils are electrically connected to each other except for a terminal between them. The outer surface is integrally coated with an insulating material while ensuring insulation.

According to a second aspect of the present invention, there is provided a coil unit for a transformer, wherein two coils made of a conductive plate and a spacer made of an insulating material are provided between the two coils. Are molded with resin by injection molding and integrated.

According to a third aspect of the present invention, the coil unit according to the first or second aspect is a secondary side coil unit, and the primary side is formed of a multilayer laminate and has an outer surface covered with an insulating material. The coil unit and the secondary side coil unit are sandwiched between a pair of cores.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the primary coil unit and the secondary coil unit have an inner peripheral diameter and an outer peripheral diameter of the primary coil and the secondary coil. Are formed equally.

According to the first and second aspects of the present invention,
Since electrical insulation is secured except for the terminal portion between the two coils, the withstand voltage (dielectric strength) between the two coils is reliably increased. In addition, since the two coils are formed integrally, the labor required for assembling the transformer is simplified. According to the second aspect of the present invention, since the spacer is provided, the withstand voltage (dielectric strength) between the two coils is reliably increased, and the two coils and the core are formed by resin molding. The withstand voltage (dielectric strength) between them is surely increased. According to the third aspect of the invention, the transformer is assembled by sandwiching the primary side coil unit and the secondary side coil unit with a pair of cores. According to the invention described in claim 4, the eddy current loss is reduced as compared with the case where the inner diameter and the outer diameter of the primary coil and the secondary coil are different.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. As shown in FIGS. 1 and 3, the transformer T of the present embodiment includes a pair of PQ cores (hereinafter simply referred to as cores) 1 and 2, two primary coil units 3 and 4, and one The secondary coil unit 5 is configured. Between the cores 1 and 2, a secondary coil unit 5 is sandwiched between two primary coil units 3 and 4.

The pair of cores 1 and 2 are made of ferrite and have the same shape. The cores 1 and 2 are formed in a shape obtained by processing a rectangular parallelepiped object. Column-shaped projections 1A and 2A are formed at the center of the cores 1 and 2, respectively.
Arc-shaped storage portions 1B and 2B are formed around 2A, and both sides of the cores 1 and 2 are cut open. The end faces 1C and 2C of the cutout portions of the cores 1 and 2
The cores 1 and 2 are formed perpendicular to the front and back surfaces.

The primary-side coil units 3 and 4 are formed in the same shape, and are constituted by multilayer laminates covered with an insulating material. Holes 3A and 4A into which the projections 1A and 2A of the cores 1 and 2 fit are formed in the center of the primary side coil units 3 and 4, respectively. Primary side coil units 3 and 4 are storage unit 1
B and 2B are provided, and the projection part 6-9 protrudes from the storage part 1B and 2B. One protruding portion 6, 8 is formed in an arc shape, and both end portions 6A, 8A
The cores 1 and 2 are formed to have a length that can contact the end faces 1C and 2C. The other protrusions 7, 9 are connected to one protrusion 6, 8
One end surfaces 7A and 9A are in contact with a straight line passing through the center of the first side and the centers of the primary side coil units 3 and 4, and the positioning surfaces 7B and 9 are in contact with the other end surfaces 1C and 2C of the cores 1 and 2.
B is formed.

As shown in FIGS. 2 to 4, the secondary coil unit 5 includes a spacer 13 made of an insulating material, and two secondary coils made of a copper plate as a punched conductive plate. 14 and 15, and the secondary coils 14 and 15 are formed in the same shape. The thickness of the secondary coils 14 and 15 is formed, for example, to about 1 mm.

As shown in FIG. 2, the secondary coils 14, 1
5 includes tap terminals 14A, 15A and terminal 1 respectively.
4B and 15B are formed. Terminal 14 for tap
A and 15A are bent so as to have a step, and the secondary coils 14 and 15 are turned upside down so that the tap terminals 14A and 15A are in contact with each other.
3 and can be arranged in parallel with the same spacing. Terminals 14A and 15A for tap and terminals 14B and 15B
Is tin-plated to prevent rust and improve the contact between the tap terminals 14A and 15A. The secondary coils 14 and 15 have the same inner and outer diameters as the coil patterns (not shown) of the primary coil units 3 and 4. The spacer 13 is formed with a ring-shaped fitting projection 13A as a positioning portion for the secondary coils 14, 15 on the front and back surfaces of the central portion. The spacer 13 has a thickness of, for example, 0.5 to 0.8 mm.

As shown in FIG. 4, the secondary coils 14, 1
5 and the spacer 13 are resin-molded by injection molding, and an insulating film 16 as an insulating material having a uniform thickness is formed on the entire outer side of the secondary coils 14 and 15. At the time of injection molding, the secondary coils 14 and 15 are arranged at predetermined positions of the mold while being fitted and positioned in the fitting projection 13A of the spacer 13. In order to minimize the damage of the secondary coil unit 5 due to thermal distortion, the resin used for injection molding and the resin of the spacer 13 are made of the same material. In this embodiment, for example, polybutylene terephthalate (PBT) is used.

The depths of the storage portions 1B and 2B are set such that the cores 1 and 2 come into contact with each other when the coil units 3, 4 and 5 are stored. When assembling the transformer T configured as described above, first, the primary coil unit 4 and the secondary coil unit 5 are stored in the storage part 2B of the core 2 in this order. Next, the primary coil unit 3 is brought into contact with the secondary coil unit 5 such that the hole 3A of the primary coil unit 3 matches the hole 5A of the secondary coil unit 5. Finally, the projection 1A of the core 1 is inserted into the hole 3A of the primary coil unit 3 and the hole 5A of the secondary coil unit 5. At this time, the primary coil units 3 and 4 are positioned with both ends of the projecting portions 6 and 8 engaged with the end faces 1C and 2C, and the secondary coil unit 5 is engaged with the engaging portions 5B.
Are engaged with the end faces 1C and 2C and are positioned.
It is sandwiched between two. One of the primary coil units 3 and 4 is inverted, and the through-holes 12A are electrically connected to each other by wiring (not shown) so that currents in the same direction flow in the respective coil patterns.

Next, the transformer T configured as described above is used.
The operation of the transformer T when this is used in a DC / DC converter circuit as a DC power supply circuit will be described. As shown in FIG. 5, the DC / DC converter circuit includes a battery E, a filter F, an inverter section I constituted by transistors Q1 to Q4, a transformer T having a secondary coil having an intermediate tap, It is constituted by a secondary circuit having diodes D1 and D2 and a capacitor C. The load R is connected between the output terminals VO. In the inverter section I, transistors Q1 and Q4
And transistors Q2 and Q3 are simultaneously ON and O, respectively.
FF. When both transistors Q1 and Q4 are ON, both transistors Q2 and Q3 are OFF simultaneously, and when both transistors Q1 and Q4 are OFF, both transistors Q2 and Q3 are OFF.
2 and Q3 are simultaneously turned on. Both transistors Q1, Q
When 4 is ON, a current flows in the direction of arrow A1 in the primary coil units 3 and 4 of the transformer T. In the secondary coil unit 5 of the transformer T, current flows in the secondary coil 14 in the direction of arrow A3, and a loop of current flowing through the diode D1, the load R, and the intermediate tap is formed. On the other hand, when both transistors Q2 and Q3 are ON,
In the primary side coil units 3 and 4, a current flows in a direction opposite to the arrow A1. And in the secondary side coil unit 5,
A current flows in the secondary coil 15 in the direction of arrow B3, and a loop of current flowing through the diode D2, the load R, and the intermediate tap is formed. And transistors Q1, Q2,
By the switching control of Q3 and Q4, a DC voltage passing through the secondary coil 14 or the secondary coil 15 is always applied to the load R. Since the number of coil turns of the primary coil units 3 and 4 is eight in total and the number of coil turns of the secondary coils 14 and 15 is one each, a voltage of 1/8 of the battery E is applied to the load R. You. This DC / DC converter circuit is mounted on, for example, an automobile, and changes the voltage of a high-voltage battery E for a driving motor to a low voltage suitable for a power supply of an auxiliary machine.

Therefore, according to the transformer T of this embodiment, the following effects can be obtained. (1) Since the transformer T is configured by sandwiching the primary coil units 3 and 4 and the resin-molded secondary coil unit 5 between the pair of cores 1 and 2,
The number of components of the transformer T and the number of assembling steps can be reduced. Therefore, the transformer T can be easily assembled. (2) The transformer T sandwiches the secondary coil unit 5 between the primary coil units 3 and 4, and the primary coil units 3, 4 and the secondary coil unit 5 sandwich the pair of cores 1 and 2. The leakage flux is reduced,
The power loss of the transformer T can be reduced. (3) The secondary coil units 5 are formed by resin molding of the secondary coils 14, 15 with the spacer 13 interposed therebetween by injection molding, so that the secondary coils 14, 15 have a uniform thickness. Since it can be covered with the insulating film 16, the core 1,
2 and the secondary coils 14, 15 and between the secondary coils 14,
The withstand voltage (dielectric strength) between 15 can be reliably increased.
Therefore, a high voltage can be applied. (4) Since the primary coil units 3 and 4 and the secondary coil unit 5 have the same inner and outer diameters of the coil pattern of the primary coil unit and the secondary coils 14 and 15, respectively, Eddy current loss can be reduced, and power loss of the transformer T can be reduced. (5) Since the resin used for the integral injection molding of the secondary coil unit 5 is made of the same material as the spacer 13 sandwiched between the secondary coils 14 and 15, their thermal expansion coefficients become equal, Damage to the secondary coil unit 5 due to distortion can be reduced. (6) Secondary coil 14, 1 of secondary coil unit 5
Since the tap terminals 14A and 15A of No. 5 are plated with tin, they prevent rust, and the tap terminals 14A and 15A
The contact property of 5A is improved. (7) Since the spacer 13 is formed with the ring-shaped fitting projection 13A, the secondary coil 1 can be used during injection molding.
Positioning of 4 and 15 becomes easy. (8) Both ends 6A and 8A of the protruding portions 6 and 8 of the primary side coil units 3 and 4 engage with the end surfaces 1C and 2C of the cores 1 and 2 to serve as positioning portions, and serve as positioning portions. ,
It stops when 2 is assembled. (9) Secondary coil 14, 1 of secondary coil unit 5
5 are formed in the same shape, so that the types of components of the secondary coil unit 5 can be reduced.

The embodiments are not limited to those described above, and may be modified as appropriate without departing from the spirit of the invention as follows. In the above embodiment, both terminals 14A, 14B, 15A, 15B of the secondary coils 14, 15 may be formed by bending. In this case, the tap terminals 14A, 15
When forming A, processing becomes easy.

The resin that molds the spacer 13 and the secondary coil unit 5 by injection molding need not be polybutylene terephthalate (PBT). Any resin can be used as long as it has heat resistance and dimensional stability. The spacer 13 and the molding resin may be different from each other as long as they are not the same, as long as they have substantially the same coefficient of thermal expansion.

As shown in FIG. 6, the primary coil unit 4 may be omitted, and the primary coil unit 3 and the secondary coil unit 5 may be sandwiched between a pair of cores 1 and 2. . The length of the projections 1A and 2A is slightly shortened. In this case, the number of parts is reduced, and the assembling of the transformer T is further facilitated. At this time, the ratio between the power supply voltage and the output voltage is 4: 1, but when it is desired to make it 8: 1, the number of turns of the coil pattern of one primary side coil unit may be made eight.

The spacer 13 may not have the fitting projection 13A. The inner and outer diameters of the coil patterns of the primary coil units 3 and 4 and the secondary coils 14 and 15 may not be the same.

The secondary coil unit 5 does not have to be molded by injection molding. Two coils 14,
It may be manufactured by any method as long as 15 is integrally formed while ensuring electrical insulation other than the tap terminals 14A and 15A.

The number of turns of the coil patterns of the primary side coil units 3 and 4 may be appropriately changed so as to obtain a desired output voltage. The thickness and diameter of the coil pattern, the spacer 13, and the secondary coils 14, 15 are determined by the transformer T
May be changed as appropriate according to the magnitude of the electric power used in.

The core of the transformer is not limited to the PQ core, but may be an E-shaped core in cross section. In this case, the primary side coil units 3 and 4 and the secondary side coil unit 5 are formed in a square shape.

The secondary coil unit 5 may be used as the primary side (input side), and the primary side coil units 3 and 4 may be used as the secondary side (output side). In this case, it is suitable for a step-up transformer.

The technical idea grasped from the embodiment and not described in the claims will be described below together with its effects. (1) In the invention described in claim 3, the spacer is formed in a ring shape, and ring-shaped fitting projections are formed on both sides of an inner peripheral edge. In this case, the space
When molding the resin by injection molding in a state where the spacer is held between the secondary coils, the positioning between the spacer and the secondary coil is facilitated.

[0031]

As described in detail above, according to the first and second aspects of the present invention, the number of transformer components and the number of assembling steps can be reduced, the assembling can be simplified, the size can be reduced, and a high voltage can be obtained. Can be applied.

According to the third aspect of the invention, the number of transformer components and the number of assembling steps can be reduced, the assembling can be simplified, the size can be reduced, and a high voltage can be applied.
According to the invention described in claim 4, eddy current loss can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a transformer according to an embodiment.

FIG. 2 is an exploded perspective view showing components of the secondary coil unit.

FIG. 3 is a perspective view of a transformer.

FIG. 4 is a schematic sectional view of a secondary side coil unit.

FIG. 5 is an electric circuit diagram of a DC / DC converter.

FIG. 6 is an exploded perspective view of a transformer according to another embodiment.

FIG. 7 is an exploded perspective view of a transformer of a conventional device.

FIG. 8 is a sectional view of a transformer.

[Explanation of symbols]

T… Transformer, 1,2… PQ core as core, 3,4
... Primary side coil unit, 5 ... Secondary side coil unit,
13 ... spacer, 14, 15 ... secondary coil, 16 ... insulating coating as insulating material.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Miwa 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Takeshi Kodera 2-1-1 Toyota-cho, Kariya-shi, Aichi Stock Company Toyota Motor Loom Works (72) Inventor Hiroki Okada 1 Haruki, Haruki, Ogo-gun, Aichi-gun, Aichi Prefecture Inside Togo Works Co., Ltd. Togo Mfg. Co., Ltd. F-term (reference) 5E043 BA01 5E044 AD03 DA01

Claims (4)

[Claims] 1. A coil unit for a transformer, comprising:
A coil unit in which two coils are integrally formed with an outer surface covered with an insulating material while ensuring electrical insulation except for a terminal portion between the two coils. 2. A coil unit for a transformer, comprising:
A coil in which two coils made of a conductive plate and a spacer made of an insulating material are resin-molded by injection molding and integrated with a spacer sandwiched between the two coils. unit. 3. The primary coil unit according to claim 1, wherein the secondary coil unit is a secondary coil unit, the primary coil unit being formed of a multilayer laminate and having an outer surface covered with an insulating material. A transformer in which a side coil unit is sandwiched between a pair of cores. 4. The transformer according to claim 3, wherein the primary coil unit and the secondary coil unit are formed such that an inner diameter and an outer diameter of the primary coil and the secondary coil are equal.