JP2001358523A - Helical antenna and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a helical antenna for a cellular phone and so on and its manufacturing method in which a space between antenna elements and a cover over the periphery does not cause tilting and which is formed at an inexpensive cost. SOLUTION: This device comprises a bar shape core 25 which is a helical antenna element made of a conductive metallic plate being fixed by a bobbin 24 made of insulating resin, and a cover 26 made of insulating resin which is separately formed and covers over the periphery of the bobbin 24. An inner wall of a hole 26A of the cover 26 contacts with the peripheral surface of a projecting part of the antenna element 22 at the periphery of the bobbin 24. A protrusion 27 formed by thermal deformation of the internal wall around the contact caused by electromagnetic heating and so on, is clamped with a side of the protrusion of the antenna element 22 and the cover 26 is clamped with the core 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical antenna mainly used for portable telephones and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, portable telephones have become widespread, and helical antennas having short dimensions and high performance have been widely used as antennas for transmitting and receiving the radio waves so as to be convenient for carrying. ing.

As a conventional helical antenna of this kind and a method of manufacturing the same, there is known a helical antenna and a method of manufacturing the same described in Japanese Patent Application Laid-Open No. 11-41019, the contents of which are shown in FIGS. Will be explained.

FIG. 22 is a cross-sectional view showing the structure of a conventional helical antenna. The helical antenna 1 has a spiral shape of an antenna element 2 in which a narrow line portion 2A formed from a conductive metal plate is spirally continuous. The inside of the shape is fixed by a bobbin part 4 made of insulating resin, a power supply fitting 3 is connected to a connecting part 2B at one end, and the outer periphery thereof is further covered with a cover 5 made of insulating resin. It is mounted and connected to the mobile phone by means of a screw or the like on the outer periphery of the power supply fitting 3.

FIG. 23 to FIG. 26 are perspective views for explaining a method of manufacturing the helical antenna 1. First, as shown in FIG. 24, a flat plate-shaped antenna element 2C arranged in a substantially U-shape is punched, and then pressed so as to protrude up and down, and connected to a spiral antenna element 2 as shown in FIG. After forming the portion 2B, FIG.
As shown in the figure, the inside of the spiral antenna element 2 and the gap between the narrow linear portions 2A are formed by outsert molding with an insulating resin, and the bobbin portion 4 for fixing between the narrow linear portions 2A is formed.
Then, when the connecting portion 6A with the conductive metal plate 6 is cut, the core 7 as the antenna element 2 having the bobbin portion 4 as shown in FIG. 26 is completed.

After connecting the power supply fitting 3 to this,
The helical antenna 1 was completed by forming the cover 5 covering the outer periphery by insert molding again with insulating resin.

[0007]

However, in the above-mentioned conventional helical antenna and the method of manufacturing the same, the core 7 as the antenna element 2 having the bobbin 4 is used.
Since a conductive portion such as a trace of cutting of the connecting portion 6A with the conductive metal plate 6 is exposed outside, the cover 5 is formed by insert molding with an insulating resin. At this time, the only part that holds the bobbin part 4 of the core 7 in the molding die without leaving a scar on the appearance of the cover 5 is the power supply fitting 3 at one end, so that the bobbin part 4 of the core 7, that is, the antenna element 2 There is a problem that the cover 5 may be inclined with respect to the cover 5, and the formation of the cover 5 by insert molding is troublesome and costly. Further, since the entire inside of the cover 5 is filled with the resin, the helical shape is formed. There was also a problem that the antenna 1 was heavy.

The present invention solves such a conventional problem, and does not cause a tilt between the bobbin portion of the core, that is, the antenna element and the cover that covers the outer periphery thereof, and efficiently covers the core with the cover. It is another object of the present invention to provide a helical antenna capable of reducing the weight of the helical antenna and a method of manufacturing the helical antenna.

[0009]

In order to achieve the above object, the present invention has the following arrangement.

[0010] The invention described in claim 1 of the present invention is, in particular,
An antenna element in which a narrow line portion processed from a conductive metal plate is spirally continuous and a rod-shaped power supply fitting connected to one end thereof, a part of the antenna element is provided on the outer periphery,
A rod-shaped core fixed by an insulating resin bobbin and a cap-shaped cover made of an insulating resin that is separately formed and covers the outer periphery of the bobbin, so that the ends of the power supply fittings project at one end, The inner wall of the hole of the cover abuts on the outer peripheral surface of the projecting portion of the antenna element on the outer periphery of the bobbin, and the inner wall around the abutting portion is thermally deformed to form a side portion of the projecting portion of the antenna element or its side. The cover has a configuration of a helical antenna in which the cover is locked to the core by engaging with the concave portion in the vicinity. With this, the cover is formed separately as a single unit, so that the cover is formed without bias and Since the inner wall of the hole of the cover is engaged with the antenna element itself projecting to the outer periphery of the bobbin, the cover covering the bobbin portion of the core, that is, the antenna element and its outer periphery No inclination between, yet inexpensive, effect that can be achieved helical antenna without scar appearance of the cover is obtained.

According to a second aspect of the present invention, in the first aspect of the present invention, in particular, the protrusion formed by heat deformation of the antenna element by the electromagnetic induction heating causes the inner wall of the hole of the cover to be thermally deformed. , The outer periphery of the bobbin part is engaged with the side part of the protruding part of the antenna element or a concave part in the vicinity thereof, whereby the cover can be efficiently and inexpensively engaged with the bobbin part of the core, that is, the antenna element. The operation and effect that a helical antenna which is stopped and has no scar on the outer appearance of the cover can be obtained.

According to a third aspect of the present invention, in the second aspect of the present invention, the thermal deformation temperature of the insulating resin forming the bobbin is higher than the thermal deformation temperature of the insulating resin forming the cover. It has a configuration that,
Even if the insulating resin on the inner wall of the cover hole is thermally deformed due to the heat generated by the antenna element due to electromagnetic induction heating, the heat can be controlled so that the insulating resin on the bobbin part of the core does not thermally deform. The effect of being locked in a stable state is obtained.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the antenna element is formed of a conductive metal plate having magnetism. Although the antenna performance is slightly inferior to an antenna element formed from a good conductive metal plate, Joule heat due to eddy current is large among the heat of the antenna element due to electromagnetic induction heating, and the efficiency is short. The effect that the cover is locked to the core is often obtained.

According to a fifth aspect of the present invention, in the second aspect, particularly, the outer diameter of the rod-shaped power supply fitting is smaller than the diameter of the spiral portion of the antenna element. Therefore, even if the power supply fitting and the antenna element generate heat due to electromagnetic induction heating,
The effect of being able to prevent the heat from being transmitted to the cover and causing thermal deformation can be obtained.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, in particular, the power supply fitting is formed integrally with the antenna element from a conductive metal plate. This makes it possible to easily form a power supply fitting having a small diameter, prevent thermal deformation of the cover due to heat generation of the power supply fitting, and reduce the number of components of the helical antenna and the number of assembling steps, so that it is inexpensive. Further, an operational effect that the electrical connection between the antenna element and the power supply fitting is stable is obtained.

According to a seventh aspect of the present invention, in accordance with the second aspect of the present invention, in particular, a plurality of ribs having a predetermined width are provided at substantially equal angular positions along the length direction of the inner wall of the hole of the cover. Is provided, and the cover is locked to the core by engaging a protrusion formed from the rib with a side of the protrusion of the antenna element on the outer periphery of the bobbin or a recess near the protrusion. Therefore, the portion of the outer periphery of the bobbin that comes into contact with the protrusion of the antenna element is
It becomes a plurality of ribs formed on the inner wall of the hole of the cover,
Since the contact area is small, the bobbin portion can be easily inserted into the hole of the cover by press-fitting, and the antenna element on the outer periphery of the bobbin portion of the protrusion formed by heat generation of the antenna element by electromagnetic induction heating. The engagement force of the protrusion with the side portion or the concave portion in the vicinity thereof can be adjusted by the number, size, and shape of the ribs, and the operation and effect of stably locking the cover to the core can be obtained.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the insulating resin of the bobbin for fixing the antenna element of the core is particularly missing at a portion which does not hinder the fixing of the antenna element. This has the effect of reducing the weight of the helical antenna without any problem in performance.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, in particular, the hole of the cover has a substantially circular cross section, and the bobbin portion of the core has an end on the side from which the power supply fitting projects. It has a circular cross section that engages with the hole of the cover, and the other portion has a non-circular cross section, and has a configuration in which there is a gap between the two, which hinders fixing of the antenna element. In addition, the entrance portion of the hole in the cover is closed and the appearance is good, and the effect that the helical antenna can be reduced most effectively can be obtained.

According to a tenth aspect of the present invention, in the first aspect of the present invention, in particular, the hole of the cover has a step with a large entrance side and a small depth, and the outer periphery of the bobbin and the antenna element A step in the same direction is also provided in the protruding portion, so that the inner wall of the hole of the cover abuts the antenna element on the outer periphery of the bobbin portion and the outer peripheral surface of the protruding portion at least near the entrance and near the back. The cover is locked to the core by engaging the protrusion of the antenna element with the side of the protrusion of the antenna element or a recess in the vicinity thereof. Since the projecting part of the element has a small portion that abuts the inner wall of the hole of the cover, and both are engaged near the entrance and near the back of the hole of the cover,
When combining the two, the bobbin can be inserted lightly into the middle of the hole in the cover, and it is only necessary to press in from that position, so that the combination work is easy, automation is possible, and also after the combination and after the formation of the protrusion. The operation and effect that the cover is stably held and locked to the core without rattling or the like can be obtained.

According to the eleventh aspect of the present invention, in particular, after a power supply fitting is connected to one end of a spiral antenna element formed from a conductive metal plate, a part of the antenna element is supplied to the outer periphery. A rod-shaped core is formed by fixing it with a bobbin that is outsert molded with insulating resin so that the ends of the metal fittings protrude from one end, respectively. After the inner wall of the antenna element is press-inserted so as to be pressed against the outer peripheral surface of the antenna element on the outer periphery of the bobbin, the antenna element is heated using an electromagnetic induction heating device, and the inner wall of the cover is pressed against the inner wall of the cover. The protrusion is formed by thermally deforming the periphery, and the protrusion is engaged with the side of the protrusion of the antenna element on the outer periphery of the bobbin or the recess near the protrusion to cover the cover. A method for manufacturing a helical antenna according to claim 1, wherein said helical antenna is locked to a core, wherein there is no inclination between a bobbin portion of the core, that is, an antenna element and a cover covering the outer periphery thereof, and further, there is no scar on the appearance of the cover. The operation and effect that the helical antenna can be manufactured efficiently and inexpensively can be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) Using Embodiment 1,
The invention of the present invention, particularly, the inventions described in claims 1 to 6, 8, 9 and 11 will be described.

FIG. 1 is a sectional view of a helical antenna according to a first embodiment of the present invention, FIG. 2 is an enlarged sectional view taken along line PP of FIG. 1, FIG. 3 is an enlarged sectional view taken along line QQ of FIG.
FIG. 4 is an enlarged sectional view taken along the line RR.

As shown in FIG. 1, this helical antenna 21 has an antenna element 22 (in the following description, a helical continuous narrow line portion 22A formed from a conductive metal plate such as copper or a copper alloy). , Element 22)
And power supply fitting 2 connected to connection portion 22B at one end thereof
3 is fixed with a bobbin 24 made of insulating resin so that a helical interior including a connection with the power supply fitting 23 is fixed so that a part of the element 22 protrudes from the outer periphery and an end of the power supply fitting 23 protrudes from one end. And a cover 26 made of a cap-shaped insulating resin that covers the outer periphery of the bobbin portion 24 of the core 25. The inner wall of the hole 26A of the cover 26 is The cover 26 is locked to the core 25 by abutting on the outer peripheral surface of the protruding portion and by engaging the protruding portion 27 around the abutting portion with the side portion of the protruding portion of the element 22. It is configured to be attached to and connected to the mobile phone by a screw portion 23A or the like provided on the power supply fitting 23.

As shown in FIG. 2, the portion where the bobbin portion 24 of the core 25 fixes the helical portion of the element 22 has a substantially oval cross-section with a non-circular cross section. The shape portion 22A is fixed by the insulating resin of the bobbin portion 24 at the left and right linear portions, and protrudes from the arc-shaped outer periphery of the insulating resin of the bobbin portion 24 at the upper and lower arc portions, as described above. The cover 26 is attached to the core 25 by engaging the side of the narrow linear portion 22A of the element 22 protruding from the outer periphery of the arc-shaped portion of the portion 24 with the projection 27 on the inner wall of the circular hole 26A of the cover 26. However, there is a gap between the linear portion of the bobbin portion 24 and the inner wall of the hole 26A of the cover 26, and a trace of cutting of the connection portion with the conductive metal plate when the element 22 is manufactured. It is protruding.

As shown in FIGS. 1 and 3, the circular end portion 24A of the bobbin 24 engages and closes the entrance of the circular hole 26A of the cover 26.

Thus, the helical antenna 21 according to the present embodiment is light in weight without hindering the fixing of the element 22, and has a good appearance since the entrance of the hole 26A of the cover 26 is closed.

Further, the power supply fitting 23 has a rod shape whose outer diameter is smaller than the diameter of the spiral portion of the element 22, and as shown in FIGS.
Is fixed by the insulating resin of the bobbin portion 24 including the connecting groove portion 23B to be integral with the core 25.

A method for manufacturing the helical antenna 21 will be described below.

In the perspective views for explaining the method of manufacturing the helical antenna shown in FIGS. 5 to 9, first, as shown in FIG.
A flat plate-shaped antenna element 22C in which narrow-width linear portions 22A are alternately arranged in a substantially U-shape on the conductive metal plate 28 is punched, and then pressed to project vertically. A helical element 22 and a U-shaped connecting portion 22B at the end are formed as shown in FIG.

Next, a power supply fitting 23 machined from a circular metal rod and having a screw portion 23A on one end and a connecting groove 23B on the other end, as shown in FIG. The power supply fitting 23 is connected and connected to the element 22 by inserting and connecting the connection groove 23B to the connection portion 22B and caulking two claws of the connection portion 22B inward (see FIG. 4).

Thereafter, as shown in FIG. 8, the inside of the spiral element 22 and the connection portion with the power supply fitting 23 are outsert-molded with an insulating resin to form each narrow linear portion 22A of the element 22. The left and right linear portions are fixed with insulating resin, the upper and lower arc portions are projected from the arc-shaped outer periphery of the insulating resin, and a bobbin portion 24 for fixing a connection portion with the power supply fitting 23 is formed. Connection part 2 with metal plate 28
By cutting 8A, a core 25 as an element 22 having a bobbin part 24 and a power supply fitting 23 as shown in FIG. 9 is completed.

Next, the core 2 formed as described above
5, a method of attaching a cap-shaped cover 26 made of insulating resin, which is separately formed, will be described.

First, as shown by the arrow in the exploded perspective view of FIG. 10, the bobbin portion 24 of the core 25 is pressed into the circular hole 26A of the cover 26 from the front end to join them together. Is a spiral narrow linear portion 22A of the element 22 protruding from the arc-shaped outer periphery of the bobbin portion 24, so that the inner wall of the hole 26A of the cover 26 protrudes to the outer periphery of the bobbin portion 24. The elements 22 are combined so as to be in contact with the outer peripheral surface of the narrow linear portion 22A of the element 22 to form a core 29 with a cover as shown in the sectional view of FIG.

Here, the diameter of the inner wall of the circular hole 26A of the cover 26 and the diameter of the outer peripheral surface of the narrow linear portion 22A of the element 22 protruding from the outer periphery of the arc-shaped portion of the bobbin portion 24 are both light. The bobbin portion 24 has a circular end 24A which is set to be pressed by force.
It is set so as to engage with the inlet portion of 6A and close without gap.

Next, the cover-equipped core 29 is attached to the holder 3 of the electromagnetic induction heating device 30 as shown in the conceptual view of FIG.
When a high-frequency current is supplied from a high-frequency oscillator 33 to a heating coil 32 wound around a holder 31 and inserted into the cover 1, the element 22 which is a conductor constituting the core 25 of the core 29 with a cover and the power supply fitting 23 Generate heat in a very short time due to hysteresis loss and Joule heat due to eddy current, and the respective temperatures rise.

The element 2 on the outer periphery of the bobbin 24
2 reaches the thermal deformation temperature of the insulating resin forming the cover 26, the narrow linear portion 22A of the element 22
26A of the cover 26 in the vicinity of being pressed against the outer peripheral surface of the cover 26
The insulating resin on the inner wall of the element 22 is softened and thermally deformed so as to relieve the stress caused by the pressing force, and the periphery of the contact portion with the narrow linear portion 22A of the element 22 protruding on the outer periphery of the bobbin portion 24 is inward. The protruding portion 27 is provided on the side of the narrow linear portion 22A.
Is formed, and the stress in the pressed portion is also eliminated.

In this state, when the supply of the high-frequency current to the heating coil 32 is stopped, the heat generation of the element 22 is also stopped, and the insulating resin of the cover 26 is hardened again.
The protrusion 27 with the raised inner wall of the element 6A is
It becomes hard in a state of being engaged with the side of the second narrow linear portion 22A.

In this way, the cover 26 is efficiently locked to the core 25, and the helical antenna 21 is completed.

The electromagnetic induction heating device 30 is made of a heat-resistant insulating material such as ceramic so that the holder 31 itself does not generate heat, and the heating coil 32 can be cooled to prevent the coil itself from generating heat. It has become.

In the above description, the element 22 has been described as being formed from a conductive metal plate 28 such as copper or a copper alloy. However, by forming this from a conductive metal plate having magnetism such as a stainless steel plate, Although the performance as an antenna is slightly inferior to the element 22 formed of a metal plate having good conductivity, the element 22 formed by electromagnetic induction heating is used.
Of the heat generated, Joule heat due to eddy current increases, the temperature rises to a predetermined temperature in a shorter time, and the cover can be more efficiently locked to the core.

Furthermore, the generation of Joule heat by the electromagnetic induction heating device 30 causes the power supply fitting 23 to generate heat together with the element 22, so that the insulating resin of the bobbin portion 24 fixing these elements may be thermally deformed. However, by setting the insulating resin forming the bobbin portion 24 to have a higher heat deformation temperature than the insulating resin forming the cover 26, even if the inner wall of the hole 26A of the cover 26 is thermally deformed,
The bobbin portion 24 can control heat generation so as not to be thermally deformed, and the cover 26 can be stably locked to the side of the narrow linear portion 22A of the element 22 of the core 25. it can.

The outer diameter of the power supply fitting 23 is smaller than the diameter of the spiral portion of the element 22.
Since the cover 26 is covered with the insulating resin and does not contact the inner wall of the hole 26A of the cover 26, the cover 26 is not thermally deformed by the heat generated.

In the case where the helical antenna is of a type which is mounted on a portable telephone using an antenna holder and makes a connection spring elastically contact the power supply fitting, and the power supply fitting 23 does not require the screw portion 23A, Instead of the U-shaped connecting portion 22B in the method for manufacturing a helical antenna described with reference to FIGS. 5 to 9 described above, as shown in a perspective view illustrating another method for manufacturing a helical antenna in FIG. If the power supply fitting 38 is formed integrally with the element 40 from the conductive metal plate 39 and is subjected to outsert molding with an insulating resin in the same manner as in the above-described manufacturing method, the outer diameter of the power supply fitting 38 naturally becomes Helical antenna smaller than the diameter of the helical portion can be formed, the number of components of the helical antenna is reduced, the cost is reduced, and the electrical connection between the element 40 and the power supply fitting 38 is reduced. It can be assumed that the stable.

As described above, the helical antenna 21 according to the present embodiment is formed without bias since the cover 26 is separately formed as a single unit, and is formed by electromagnetic induction heating so that the inner wall of the circular hole 26A of the cover 26 is formed. Since the protrusion 27 efficiently formed on the inside of the core 25 is engaged with the element 22 protruding from the outer periphery of the bobbin 24 having a non-circular cross section, the bobbin 24 of the core 25, that is, the element 2
There is no inclination between the cover 2 and the cover 26 that covers the outer periphery of the cover 2, so that it is inexpensive and lightweight.

In the above description, the hole 2 of the cover 26
The protrusion 27 formed at the raised portion of the insulating resin portion of the inner wall of 6A due to thermal deformation is engaged with the bobbin portion 24.
Although the side of the narrow linear portion 22 </ b> A of the outer element 22 has been described, the conductive metal plate 28
When the engagement is insufficient due to the small thickness of
As shown in the sectional view of FIG. 4, a concave portion 35 is provided in the insulating resin of the bobbin portion 34 in the vicinity of the narrow linear portion 22A of the element 22 on the outer periphery of the bobbin portion 34, and the hole 26 of the cover 26 is provided here.
A protrusion 36 formed by thermally deforming the insulating resin on the inner wall of A
Can be surely engaged.

Further, as shown in the cross-sectional view of FIG. 14, when the lacking portion 37 of the insulating resin is provided at the center of the bobbin portion 34,
The insulating resin portion can be reduced without hindering the fixing of the element 22, and a lighter helical antenna can be obtained.

(Embodiment 2) Using Embodiment 2,
The invention described in claim 7 will be described.

FIG. 15 is a sectional view of a helical antenna according to a second embodiment of the present invention, FIG. 16 is an enlarged sectional view taken along line S--S of FIG. 15, and FIG. 17 is an exploded perspective view of the same.

In the description of the present embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and the detailed description is omitted.

A helical antenna 41 according to the present embodiment shown in FIG. 15 includes an element 22 having a narrow linear portion 22A spirally connected thereto and a power supply fitting 23 connected to a connection portion 22B at one end thereof. A rod-shaped core 25 formed by fixing the inside of the spiral with a bobbin 24 made of insulating resin so that a part protrudes from the outer periphery and an end of the power supply fitting 23 protrudes from one end, as shown in FIG. The helical antenna 21 according to the first embodiment is the same as the helical antenna 21 except that a cover 42 made of a cap-like insulating resin in which the bobbin 24 is inscribed is covered so as to cover the outer periphery of the core 25.

That is, on the inner wall of the hole 42A of the cover 42, twelve ribs 43 of a predetermined width are provided at substantially equal angular positions along the length direction thereof, and as shown in FIG. In each of the upper and lower arc-shaped portions of the 25 bobbin portions 24, four of the ribs 43 abut on the outer peripheral surface of the projecting portion of the element 22, and as shown in FIG.
The cover 42 is locked to the core 25 by the projections 44 of the ribs 43 around the abutting portion engaging with the projections of the element 22.

In the upper and lower arc-shaped portions of the bobbin portion 24 of the core 25, the number of the ribs 43 contacting the outer peripheral surface of the projecting portion of the element 22 depends on the angular position when the core 25 and the cover 42 are combined. However, the number of abutting on the upper and lower arc-shaped portions of the bobbin portion 24 is the same,
Further, the circular end 24A of the bobbin 24 closes the entrance of the circular hole 42A of the cover 42 as in the first embodiment.

The method of mounting the cover 42 made of an insulating resin separately formed on the core 25 is almost the same as that of the first embodiment, but as shown by an arrow in the exploded perspective view of FIG. When the bobbin 24 is inserted into the hole 42A of the cover 42, the inner circumference of the twelve ribs 43 provided on the inner wall of the hole 42A of the cover 42 A core 45 with a cover (not shown) is assembled by being pressed against the outer peripheral surface of the linear portion 22A with a predetermined pressure.

At the time of this mounting and combination, the portion where the inner wall of the hole 42A of the cover 42 comes into contact with the protruding portion of the element 22 on the outer periphery of the bobbin portion 24 becomes eight or six of the twelve ribs 43. Since the contact area is reduced, the bobbin portion 24 can be easily pressed into the hole 42A of the cover 42 and assembled.

The element 2 on the outer periphery of the bobbin portion 24
The cover 42 is engaged with the narrow linear portion 22 </ b> A of the
Is formed by the rib 43 provided on the inner wall of the hole 42A of the cover 42 by the heat generated by the electromagnetic induction heating of the core 45 with the cover, similarly to the first embodiment.

In order to prevent the bobbin portion 24 from being thermally deformed when the core 45 with the cover is heated by electromagnetic induction heating, the insulating resin forming the bobbin portion 24 is assumed to have a higher heat deformation temperature than the insulating resin forming the cover 42. In other words, as in the first embodiment, the cover 42 can be stably locked by the core 25.

As described above, the helical antenna 41 according to the present embodiment covers the bobbin portion 24 of the core 25 with the cover 4.
The insertion force at the time of press-fitting into the second hole 42A and the engaging force for locking the cover 42 to the core 25 are determined by the rib 43 provided on the inner wall of the hole 42A of the cover 42. By adjusting the number, the size, and the shape, the cover 42 can be easily and stably locked to the core 25.

(Embodiment 3) Using Embodiment 3,
The invention described in claim 10 will be described.

FIG. 18 is a sectional view of a helical antenna according to a third embodiment of the present invention, and FIG. 19 is an exploded sectional view thereof.

In the description of the present embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and the detailed description is omitted.

The helical antenna 46 according to the present embodiment shown in FIG. 18 includes an element 47 having a narrow linear portion 47A spirally connected thereto and a power supply fitting 23 connected to a connection portion 47B at one end thereof. The helical interior is fixed with a bobbin 48 made of insulating resin so that a part thereof protrudes from the outer periphery and the power supply fitting 23 protrudes from one end.
9 is formed, and a cap-shaped cover 50 made of insulating resin is provided so as to cover the outer periphery thereof.
8 that the projection 51 formed from the inner wall of the hole 50A of the cover 50 is engaged with the side of the element 47 on the outer periphery of the bobbin 48 so that the cover 50 is locked. The same as the helical antenna 21 of the first embodiment, but the outer periphery of the bobbin portion 48 of the core 49 and the cover 50
The configuration of the engaging portion of the hole 50A with the inner wall is different.

That is, as shown in FIGS. 18 and 19, the circular hole 50A of the cover 50 has a large-diameter portion 5
0B, a small-diameter portion 50C is provided from the step portion 50D to the back, and the bobbin portion 48 of the core 49 has a circular shape in which an end from which the power supply fitting 23 projects is engaged with an entrance portion of the circular hole 50A of the cover 50. The cross-section 48A has a middle portion 48B of a substantially oval cross section and a small-diameter portion 48C at the front end where the oval arc-shaped portion is slightly smaller.

On the other hand, the narrow linear portion 47A of the spiral element 47 fixed to the insulating resin of the bobbin portion 48
First spiral portion 47C close to connection portion 47B with power supply fitting 23
Protrudes from the outer periphery of the arc-shaped insulating resin of the intermediate portion 48B of the bobbin portion 48, and from there to a leading end becomes a constant diameter portion 47D which becomes thinner until it is hidden by the arc-shaped insulating resin of the intermediate portion 48B of the bobbin portion 48. However, the final spiral portion 47E protrudes from the arc-shaped insulating resin of the small-diameter portion 48C at the tip of the bobbin portion 48.

When the bobbin portion 48 of the core 49 is inserted into the hole 50A of the cover 50 as shown by an arrow in FIG. 19, the two are combined as a core 52 with a cover as shown in the sectional view of FIG.

In the core 52 with the cover, the cover 5
The hole 50A and the outer periphery of the bobbin portion 48 are connected to the large-diameter portion 50B of the hole 50A by engagement of the circular cross-section 48A at the end of the bobbin portion 48 with the entrance portion and the bobbin portion near the same. The first helical portion 47C of the element 47 protruding on the outer periphery of the abutment 48 comes into contact with the small diameter portion 50C at the back of the hole 50A.
7E is in contact therewith, and in the other part of the large diameter part 50B of the hole 50A, a fixed interval is formed between the middle part 48B of the bobbin part 48 and the constant diameter part 47D of the element 47 and the inner wall of the hole 50A. Is kept.

Therefore, as shown by the arrow in FIG. 19, when inserting the bobbin portion 48 of the core 49 into the hole 50A of the cover 50 and assembling, it is possible to lightly insert the bobbin portion up to the position shown in the sectional view of FIG. In this state, it is sufficient to press-fit both of them, so that the assembling work is easy and automation is possible, and after the assembling, the cover 50 is stably held on the core 49 without rattling or the like.

In the core 52 with the cover thus formed, the inner wall of the hole 50A of the cover 50 and the outer peripheral surface of the projecting portion of the element 47 on the outer periphery of the bobbin portion 48 are in contact with each other in the vicinity of the entrance of the cover 50 and at the back. Therefore, as shown in FIG. 18, the projection 51 formed by the heat generated by the electromagnetic induction heating similar to that of the first embodiment has the first helical portion 47C and the last helical portion 47 of the element 47 that is the contact portion.
E is formed near the first spiral portion 47C and the side portion of the final spiral portion 47E of the element 47, respectively.
The cover 50 is locked to the core 49.

In order to prevent the bobbin portion 48 from being thermally deformed when the cover-equipped core 52 generates heat by electromagnetic induction heating, the insulating resin forming the bobbin portion 48 is assumed to have a higher heat deformation temperature than the insulating resin forming the cover 50. In other words, the cover 50 can be stably locked by the core 49 as in the first embodiment.

In the above description, the hole 5 of the cover 50
The protrusion 51 formed by thermally deforming the insulating resin portion of the inner wall of the 0A is engaged with the element 4 on the outer periphery of the bobbin portion 48.
7 are the side portions of the first spiral portion 47C and the final spiral portion 47E, but if this alone is not enough,
The number of the narrow linear portions 47A of the first spiral portion 47C and the final spiral portion 47E may be increased, and a concave portion is provided in the insulating resin of the bobbin portion 48 near the narrow linear portion 47A. The protrusion 51 may be engaged.

As described above, in the helical antenna 46 according to the present embodiment, the projecting portion of the element 47 on the outer periphery of the bobbin portion 48 of the core 49 has a small portion in contact with the inner wall of the hole 50A of the cover 50. Since the two are engaged near the entrance and near the back of the hole 50A, the bobbin portion 48 can be lightly inserted halfway into the hole 50A of the cover 50 when the two are combined, and it is sufficient to press-insert from that position. The assembling work is easy, automation is possible, and after the assembling and after the formation of the projections 51, the cover 50 is stably held on the core 49 without rattling or the like.
This has the effect of being locked.

[0072]

As described above, according to the present invention, a rod-shaped core in which a helical antenna element processed from a conductive metal plate is fixed by a bobbin portion made of an insulating resin, and an insulation covering the outer periphery of the bobbin portion. A protrusion formed by a resin cover, with the inner wall of the hole of the cover abutting the outer peripheral surface of the projecting portion of the antenna element on the outer periphery of the bobbin, and the inner wall around the abutting portion being thermally deformed by electromagnetic induction heating or the like. The cover engages with the core by engaging the side of the projecting portion of the antenna element, and the cover is formed separately as a single unit. Since the inner wall of the hole of the cover is engaged and locked with the antenna element itself protruding from the outer periphery of the antenna, the antenna is inclined between the bobbin portion of the core, that is, the antenna element and the cover that covers the outer periphery. Without, inexpensively, in which an effect of realizing a helical antenna without scar appearance of the cover.

[Brief description of the drawings]

FIG. 1 is a sectional view of a helical antenna according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along the line PP of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line QQ in FIG. 1;

FIG. 4 is an enlarged sectional view taken along line RR in FIG. 1;

FIG. 5 is a perspective view illustrating the manufacturing method.

FIG. 6 is a perspective view illustrating the manufacturing method.

FIG. 7 is a perspective view illustrating the manufacturing method.

FIG. 8 is a perspective view illustrating the manufacturing method.

FIG. 9 is a perspective view illustrating the manufacturing method.

FIG. 10 is an exploded perspective view of the same.

FIG. 11 is a sectional view of the core with the cover.

FIG. 12 is a conceptual diagram of the electromagnetic induction heating device.

FIG. 13 is a perspective view illustrating another manufacturing method.

FIG. 14 is a cross-sectional view of another configuration.

FIG. 15 is a sectional view of a helical antenna according to a second embodiment of the present invention.

FIG. 16 is an enlarged sectional view taken along line SS in FIG.

FIG. 17 is an exploded perspective view of the same.

FIG. 18 is a sectional view of a helical antenna according to a third embodiment of the present invention.

FIG. 19 is an exploded sectional view of the same.

FIG. 20 is a sectional view of the core with the cover.

FIG. 21 is a sectional view illustrating the assembling method.

FIG. 22 is a sectional view of a conventional helical antenna.

FIG. 23 is a perspective view illustrating the manufacturing method.

FIG. 24 is a perspective view illustrating the manufacturing method.

FIG. 25 is a perspective view illustrating the manufacturing method.

FIG. 26 is a perspective view illustrating the manufacturing method.

[Explanation of symbols]

 21, 41, 46 Helical antenna 22, 22C, 40, 47 Antenna element 22A, 47A Narrow linear part 22B, 47B Connection part 23, 38 Power supply fitting 23A Screw part 23B Connection groove part 24, 34, 48 Bobbin part 24A End part 25,49 Core 26,42,50 Cover 26A, 42A, 50A Hole 27,36,44,51 Protrusion 28,39 Conductive metal plate 29,45 Core with cover 30 Electromagnetic induction heating device 31 Holder 32 Heating coil 33 High frequency oscillator 35 Recessed part 37 Missing part 43 Rib 47C First spiral part 47D Constant diameter part 47E Final spiral part 48A Circular cross section 48B Middle part 48C Small diameter part 50B Large diameter part 50C Small diameter part 50D Step part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Sako 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. F term (reference) 5J046 AA07 AA19 AB12 BA00 QA02 QA05

Claims (11)

[Claims] 1. An antenna element in which a narrow line portion processed from a conductive metal plate is spirally continuous includes a rod-shaped power supply fitting connected to one end of the antenna element. A rod-shaped core fixed by an insulating resin bobbin so that an end of the power supply fitting protrudes from one end, and a cap having a hole formed separately from the insulating resin and covering the outer periphery of the bobbin The inner wall of the hole of the cover is in contact with the outer peripheral surface of the projecting portion of the antenna element on the outer periphery of the bobbin, and the inner wall around the abutting portion is thermally deformed to form the protrusion. A helical antenna in which the cover is locked to the core by engaging the side of the protrusion of the antenna element or a concave portion near the protrusion. 2. A projection formed by thermally deforming an inner wall of a hole of a cover due to heat generation of an antenna element due to electromagnetic induction heating, is formed on a periphery of a bobbin portion at a side of the projection of the antenna element or a recess near the projection. The helical antenna of claim 1 engaged. 3. The helical antenna according to claim 2, wherein the thermal deformation temperature of the insulating resin forming the bobbin is higher than the thermal deformation temperature of the insulating resin forming the cover. 4. The helical antenna according to claim 2, wherein the antenna element is formed from a conductive metal plate having magnetism. 5. The helical antenna according to claim 2, wherein the outer diameter of the rod-shaped power supply fitting is smaller than the diameter of the spiral portion of the antenna element. 6. The helical antenna according to claim 5, wherein the rod-shaped power supply fitting is formed integrally with the antenna element from a conductive metal plate. 7. Along the length of the inner wall of the cover hole,
A plurality of ribs having a predetermined width are provided at substantially equal angular positions, and a protrusion formed from the rib engages with a side portion of the protrusion of the antenna element on the outer periphery of the bobbin portion of the core or a recess near the protrusion. The helical antenna according to claim 2, wherein the cover is locked to the core by the following. 8. The helical antenna according to claim 1, wherein the insulating resin of the bobbin for fixing the antenna element of the core is missing in a portion that does not hinder the fixing of the antenna element. 9. A hole in the cover has a substantially circular cross section, a bobbin portion of the core has a circular cross section in which an end on the side from which the power supply fitting projects is engaged with the hole in the cover, and the other portion has a non-circular cross section. Yes,
9. The helical antenna according to claim 8, having a gap between the two. 10. A hole in the cover is formed with a step having a large entrance side and a small depth, and a step in the same direction is provided on the outer periphery of the bobbin portion of the core and the projection of the antenna element.
The inner wall of the hole of the cover is in contact with the outer peripheral surface of the projecting portion of the antenna element on the outer periphery of the bobbin at least near the entrance and near the back thereof, and the projecting portion around the contacting portion is the projecting portion of the antenna element. 2. The helical antenna according to claim 1, wherein the cover is locked to the core by engaging with a concave portion at or near a side portion of the helical antenna. 11. A power supply fitting is connected to one end of a spiral antenna element processed from a conductive metal plate, and then a part of the antenna element is exposed to the outer periphery and an end of the power supply fitting is exposed to one end. As described above, a rod-shaped core is formed by fixing a bobbin portion outsert-molded with an insulating resin, and an inner wall of a hole of the cover is formed on an antenna on the outer periphery of the bobbin portion with respect to a cap-shaped cover separately formed of the insulating resin. After press-fitting and assembling so as to press against the projecting part outer peripheral surface of the element, the antenna element is heated using an electromagnetic induction heating device to thermally deform the press-contact part of the inner wall of the hole of the cover and its periphery. The cover is formed by forming a protrusion and engaging the protrusion with a side of the protrusion of the antenna element on the outer periphery of the bobbin or a recess near the protrusion. A method for manufacturing the helical antenna according to claim 1, wherein the helical antenna is locked to the core.