JP3581350B2 - Pot type core / rivet type core choke coil - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pot-type core / rivet-type core choke coil, and more particularly, to a pot-type core in which a top surface of the rivet-type core is closely opposed to a top wall of the pot-type core to form a magnetic path gap G.・ Related to rivet type core choke coils.
[0002]
[Prior art]
A conventional example will be described with reference to FIG.
Reference numeral 10 denotes a pot type core made of ferrite. Reference numeral 101 denotes a top wall of the square pot-shaped core 10. Reference numeral 103 denotes a side wall of the pot type core 10. A notch 104 is formed at the lower part of the corner where the side walls 103 adjacent to each other intersect. The pot type core 10 fills a metal mold with ferrite fine powder, pressurizes and molds. The pressure-molded body of the pot-shaped core 10 made of the fine ferrite powder is then fired at a high temperature to form the ferrite pot-shaped core 10.
[0003]
The coil 3 is formed by spirally deforming a copper wire. Reference numeral 31 denotes a coil terminal. The coil 3 is formed by spirally deforming a copper wire and then coating the surface with an insulating material coating. The coil 3 is formed by winding the number of turns corresponding to the required inductance.
The terminal 4 includes a mounting portion 44 having a U-shaped cross section, a coil connecting portion 45 integrally extended from the mounting portion 44, and a locking projection 46 formed on the upper surface of the coil connecting portion 45.
The rivet-type core 20 made of ferrite includes a square bottom plate 201 and a magnetic core portion 204 that is provided upright at the center of the bottom plate 201. The height of the magnetic core portion 204 is made lower than the height of the inner surface of the side wall 103 of the pot-shaped core 10, and a magnetic field is formed between the inner surface of the top wall 101 of the pot-shaped core and the end surface of the magnetic core portion 204 of the rivet-shaped core. A road gap G is formed. By adjusting the gap G, the inductance of the coil 3 is set. Reference numeral 202 denotes a fitting thin portion formed at an intermediate portion between two opposing sides of the bottom plate 201, and the mounting portion 44 of the terminal 4 having a U-shaped cross section is fitted and fixed. Reference numeral 203 denotes a terminal mounting surface, which is a region provided with a step lower than the surface of the bottom plate 201 by the thickness corresponding to the thickness of the terminal 4.
The rivet type core 20 also fills a metal mold with ferrite fine powder and pressurizes it, thereby integrally molding the magnetic core 204 and the bottom plate 201. The rivet-type core pressure-formed body made of the ferrite fine powder is then fired at a high temperature to form the rivet-type core 20.
[0004]
To explain how to assemble the choke coil,
(1) The terminal 4 is fitted and fixed to the terminal mounting surface 203 and the fitting thin portion 202 of the rivet type core 20.
(2) The coil 3 is fitted to the magnetic core portion 204 of the rivet type core 20.
{Circle around (3)} Next, the coil end portion 31 of the coil 3 is soldered to the coil connection portion 45 of the terminal 4. At this time, the coil end portion 31 is temporarily fixed to the locking projection 46 formed on the upper surface of the coil connection portion 45.
{Circle around (4)} An epoxy-based thermosetting synthetic resin adhesive is applied to the peripheral end face of the opening of the pot type core 10 and the surface of the bottom plate 201 of the rivet type core 20.
{Circle around (5)} With the gap G formed between the top wall 101 of the pot-shaped core 10 and the end surface of the magnetic core 204 of the rivet-shaped core 20, the two are fixedly joined.
The outer dimensions of the pot-type core / rivet-type core choke coil are, for example, 5.times. It is a square shape of 0 mm and the height is 2. It is as small as about 0 mm.
[0005]
[Problems to be solved by the invention]
In the conventional example of the choke coil described above, both the pot type core and the rivet type core are formed by filling a metal mold with ferrite fine powder, pressing and molding, and then firing at a high temperature. By the way, it is difficult to say that the method of forming and firing the ferrite fine powder is a processing method with high processing accuracy, and warpage remains in the completed pot type core and rivet type core. In particular, when warpage occurs in the top wall 101 of the pot-type core and the bottom plate 201 of the rivet-type core, the warpage causes a variation in the gap G formed by the magnetic core portion 204 that is integrally provided on the top wall 101 and the bottom plate 201. Occurs. Due to the fact that the gap G formed by the top wall 101 and the magnetic core 204 cannot always be made uniform, it is not easy to uniformly manufacture and control the inductance of the completed choke coil. The illustrated length and width are 5. It is a square shape of 0 mm and the height is 2. In the case of a small pot type core / rivet type core choke coil of about 0 mm, the management of the inductance becomes more difficult.
[0006]
The above-described conventional example of the choke coil employs a configuration in which an epoxy-based synthetic resin adhesive is applied to the peripheral surface of the opening of the pot-shaped core 10 and the surface of the bottom plate 201 of the rivet-shaped core 20, and the two are joined and fixed. I have. This choke coil is based on the premise that reflow soldering is performed when connecting and fixing it to a printed wiring board, and is exposed to high heat after manufacturing. In the choke coil, the pot type core and the rivet type core are deformed even by the high heat, and the gap G fluctuates. In extreme cases, the bond between the pot core and the rivet core may come off. In addition, the gap G may fluctuate depending on an externally applied impact.
The present invention provides a pot-type core / rivet-type core choke coil that solves the above-mentioned problems.
[0007]
[Means for Solving the Problems]
Claim 1: A rectangular pot-shaped core 10 having a top wall 101 and a side wall 103 integrally formed with the top wall, and a bottom plate 201 and a magnetic core portion 204 which is integrally formed with the bottom plate and stands upright at the center thereof. Rivet-type core 20, the coil 3 fitted to the magnetic core 204, the U-shaped terminal 40, and the top surface of the magnetic core 24 on the top wall 101 of the pot-type core 10. In the pot-type core / rivet-type core choke coil in which the gap G is formed and the pot-type core 10 is put on the rivet-type core 20 and interconnected, the U-shaped terminal 40 has a strong spring property. It is composed of a mounting portion 44 having a U-shaped cross section, a coil connecting portion 45 integrally extended from the mounting portion 44, and a locking projection 46 formed at an end of the coil connecting portion 45, and is formed in a square shape. Pot type core 10 A notch 104 is formed at the lower part of the corner where the side wall 103 adjacent to each other intersects, and a terminal engaging recess 105 is formed on both of a pair of opposing sides on the upper surface of the top wall 101, and the side wall of the pot type core 10 is formed. The rivet-type core 20 formed to have a shape and size corresponding to the inner periphery of the cross section of 103 is formed at a corner 208 having a shape obtained by removing a pair of opposed corners of the square bottom plate 201, Terminal engagement regions 209 are formed on both sides of the pair of opposed sides on the bottom surface of the bottom plate 201, the spacer 5 made of a non-magnetic material is interposed in the gap G, and the terminal engagement recess 105 of the top wall 101 and the bottom plate 201 are formed. A pot-shaped core / rivet-type core choke coil in which a U-shaped cross-section mounting portion 44 of the U-shaped cross-section terminal 40 was engaged and fixed to the terminal engaging region 209 was formed.
[0008]
Claim 2: In the pot-type core / rivet-type core choke coil according to claim 1, a pot-type core with a thermosetting synthetic resin adhesive applied to the terminal engagement concave portion 105 and the terminal engagement region 209. A rivet-type core choke coil was constructed.
Claim 3: In the pot type core / rivet type core choke coil according to any one of claims 1 and 2, the thickness of the bottom plate 201 of the rivet type core 20, the height of the magnetic core portion 204, and A pot-type core / rivet-type core choke coil was designed and manufactured so that the sum of the thicknesses of the spacers 5 was adjusted to a height corresponding to the height of the inner surface of the side wall 103 of the pot-type core 10.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In FIGS. 1 and 2, members common to those of the conventional example are denoted by common reference numerals.
A cutout portion 104 is formed at the lower part of the corner where the adjacent sidewalls 103 of the pot-shaped core 10 intersect. A terminal engaging recess 105 is formed on both sides of the pair of opposed sides on the upper surface of the top wall 101 of the pot-shaped core 10.
Reference numeral 40 denotes a U-shaped terminal, which is formed by using a metal material such as phosphor bronze to impart strong spring properties. The U-shaped cross-section terminal 40 is formed at an end by making a cut in the vicinity of the end of the mounting portion 44, the coil connecting portion 45 integrally formed from the mounting portion 44, and the coil connecting portion 45. It comprises a locking projection 46. The mounting portion 44 having a U-shaped cross section requires a large force to expand the U-shaped portion, and the mounting portion 44 is expanded to allow a certain member to be interposed between the parallel portions having the U-shape. When the expanding force is released, the interposed member is sandwiched between the parallel portions of the mounting portion 44 with a strong force.
[0010]
The rivet-type core 20 has a pair of opposed corners of the square bottom plate 201 formed at corners 208 having corners removed. The terminal accommodating portion 12 is formed by the corner portion 208 of the rivet type core 20 and the cutout portion 104 of the pot type core 10. The shape and dimensions of the square bottom plate 201 are set to those corresponding to the inner circumference of the cross section of the side wall 103 of the pot-shaped core 10. Reference numeral 209 denotes a terminal engagement area, which is formed on both of a pair of opposed side portions on the lower surface of the bottom plate 201.
Reference numeral 5 denotes a spacer made of a non-magnetic material, which is formed of a disk having the same shape as the end face of the magnetic core portion 204 of the rivet core 20. The spacer 5 forms a gap G of a magnetic path between the inner surface of the top wall 101 of the pot-type core and the end surface of the magnetic core 204 of the rivet-type core.
[0011]
Here, the above pot-type core / rivet-type core choke coil has a sum of the thickness of the bottom plate 201 of the rivet-type core 20, the height of the magnetic core 204, and the thickness of the spacer 5. It is designed and manufactured to a height corresponding to the height of the inner surface of the side wall 103 of the ten. Thus, the size of the gap G formed between the inner surface of the top wall 101 of the pot-type core and the end face of the magnetic core 204 of the rivet-type core can be defined by the design thickness of the spacer 5. That is, by adjusting the thickness of the spacer 5, the inductance of the choke coil can be regulated to the adjusted value.
A method of assembling a choke coil will be described with reference to FIG.
[0012]
{Circle around (1)} The spacer 5 and the air-core coil 3 are assembled to the rivet-type core 20 in this order. That is, the spacer 5 is placed on the upper end surface of the magnetic core 204, and the air-core coil 3 is fitted to the magnetic core 204.
{Circle around (2)} The pot type core 10 is put on the rivet type core 20 from above. In this case, the notch 104 formed at the lower part of the corner of the pot-shaped core 10 is put on the corner 208 of the rivet-shaped core 20 while being aligned vertically. Prior to covering, an adhesive is applied to the inner peripheral surface of the open end of the side wall 103 of the pot-shaped core 10. With the pot-type core 20 covered on the rivet-type core 20, the peripheral end surface of the bottom plate 201 of the rivet-type core 20 is fitted to the pot-type core 10, so that the bottom plate 201 of the rivet-type core 20 faces the rivet-type core 20. The terminal accommodating portion 12 is formed between the corner 208 having a shape with the corner removed and the notch 104 at the lower portion of the corner where the side wall 103 of the pot-shaped core 10 intersects.
[0013]
{Circle around (3)} A thermosetting synthetic resin adhesive is bonded to the terminal engaging recesses 105 on the pot type core 10 side and the terminal engaging area 209 where the U-shaped terminal 40 on the lower surface of the bottom plate 201 of the rivet type core 20 engages. Apply the agent.
{Circle around (4)} The U-shaped terminal 40 is expanded in the terminal-engaging recess 105 of the pot type core 10 on which the adhesive is applied and the terminal-engaging region 209 on the lower surface of the bottom plate 201 of the rivet-type core 20 where the adhesive is applied. To resiliently engage. As a result, the pot-shaped core 10 and the rivet-shaped core 20 interposed between the U-shaped parallel portions by expanding the mounting portion 44 release the expanding force, so that the terminal engaging recess 105 and the terminal It is sandwiched between the parallel portions of the mounting portion 44 with a strong force between the engagement regions 209. Then, the coil connecting portion 45 and the locking projection 46 of the U-shaped terminal 40 project from the pot-shaped core 10 to the outside from the coil connecting portion 45 and are positioned and accommodated in the terminal accommodating portion 12.
(5) After the adhesive is dried, the coil end portion 31 of the coil 3 is temporarily fixed to the locking projection 46 of the terminal 4 and soldered to the coil connection portion 45.
[0014]
【The invention's effect】
As described above, according to the present invention, the spacer is interposed in the gap formed between the top wall of the pot type core and the upper end surface of the magnetic core of the rivet type core, and the pot type core and the rivet type By sandwiching the core with the U-shaped terminal 40, a pot-type core / rivet-type core choke coil with improved inductance variation can be formed.
That is, the U-shaped terminal 40 is expanded and elastically engaged with the terminal-engaging concave portion 105 of the pot-shaped core 10 and the terminal-engaging region 209 on the lower surface of the bottom plate 201 of the rivet-shaped core 20 where the adhesive is applied. By joining, the pot-type core 10 and the rivet-type core 20 interposed between the U-shaped parallel portions by expanding the attachment portion 44 release the expanding force, and It is sandwiched between the parallel portions of the mounting portion 44 with a strong force between the terminal engagement regions 209. Therefore, the spacer 5 is sandwiched between the top wall of the pot-type core and the upper end surface of the magnetic core portion 204 of the rivet-type core, and the top wall of the pot-type core warps upward or the rivet-type core Even if the bottom plate 201 of the magnetic head 204 is bent downward and the upper end surface of the magnetic core 204 is displaced downward, the top wall and the magnetic core are driven to approach each other, and the gap G is set to the spacer 5. It is limited to the thickness of. Conversely, even if the top wall of the pot-shaped core is warped downward and the bottom plate 201 of the rivet-shaped core is warped upward and the upper end surface of the magnetic core portion 204 is displaced upward, the top wall and the magnetic material are not deformed. The spacer 5 interposed between the cores limits the mutual approach by the driving of the top wall and the magnetic core, and the gap G is limited to the thickness of the spacer 5. The gap G that determines the inductance of the choke coil is ultimately determined by the set thickness of the spacer 5, and the variation in the inductance of the choke coil is improved.
[0015]
And, between the pot type core 10 and the rivet type core 20, the U-shaped terminal 40 is joined to the two, and the two are engaged with each other in such a direction that they are strongly connected to each other. Even if high heat is applied during reflow soldering or an external shock is applied, the deformation of the top wall 101 and the bottom plate 201 and the peeling of the joint between the pot-shaped core and the rivet-shaped core are caused by the pot-shaped core 10. The rivet-type core 20 is suppressed by being elastically held by the U-shaped terminal 40 in cross section.
[0016]
By the way, although the above pot type core / rivet type core choke coil is made of ferrite, the bottom plate 201 of the rivet type core 20 and the top wall 101 of the pot type core 10 are bent and deformed by applying a force in the thickness direction. I do. Therefore, the sum of the thickness of the bottom plate 201 of the rivet-type core 20, the height of the magnetic core 204, and the thickness of the spacer 5 is designed and manufactured to a height corresponding to the height of the inner surface of the side wall 103 of the pot-type core 10. By doing so, the thickness of the spacer 5 can be changed to be thin or thick within the range of the sum of the deformation amounts of the bottom plate 201 and the top wall 101. Choke coils with different inductance values can be manufactured within the sum of the quantities.
[Brief description of the drawings]
FIG. 1 illustrates an embodiment.
FIG. 2 illustrates a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pot type core 101 Top wall 103 Side wall 104 Notch 105 Terminal engagement concave part 12 Terminal accommodating part 20 Riveted core 201 Bottom plate 202 Fitting thin part 203 Terminal mounting surface 204 Magnetic core part 208 Corner part 209 Terminal engagement area 3 Coil 31 Coil terminal part 40 U-shaped cross section terminal 44 Mounting part 45 Coil connecting part 46 Locking projection 5 Spacer G Gap

Claims (3)

A rivet-type core having a top wall and a rectangular pot-shaped core composed of a side wall formed integrally with the top wall, and having a bottom plate and a magnetic core portion erected at the center thereof integrally with the bottom plate, It has a coil fitted to the magnetic core, has a U-shaped cross section terminal, forms a gap on the top wall of the pot-type core by making the upper end surface of the magnetic core close to and oppose, and forms a rivet type pot-type core. In a pot-type core / rivet-type core choke coil that is interconnected over a core,
The U-shaped cross section terminal is configured by imparting a strong spring property, and comprises a mounting section having a U-shaped cross section, a coil connecting section integrally formed from the mounting section, and a locking projection formed at an end of the coil connecting section. Consisting of
A notch is formed at the lower part of the corner where the side walls adjacent to each other of the rectangular pot-shaped core intersect, and a terminal engagement recess is formed on both of a pair of opposing sides on the top wall top surface,
The rivet-type core formed into a shape and size corresponding to the inner periphery of the cross section of the side wall of the pot-type core is formed at a corner having a shape obtained by removing a pair of opposing corners of the square-shaped bottom plate, Terminal engagement areas are formed on both of the pair of opposed sides on the bottom plate lower surface,
A spacer made of a non-magnetic material is interposed in the gap,
A pot type core / rivet type core choke coil, wherein a U-shaped cross-section mounting portion of a U-shaped cross section terminal is fixedly engaged with a terminal engaging concave portion of a top wall and a terminal engaging region of a bottom plate. The pot type core / rivet type core choke coil according to claim 1,
A pot type core / rivet type core choke coil, wherein a thermosetting synthetic resin adhesive is applied to the terminal engaging concave portion and the terminal engaging region. A pot type core / rivet type core choke coil according to any one of claims 1 and 2,
A pot type core characterized in that the sum of the thickness of the bottom plate of the rivet type core, the height of the magnetic core portion, and the thickness of the spacer is designed to a height corresponding to the height of the side wall surface of the pot type core.・ Rivet type core choke coil.

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