JP2005192173A - Mounting structure of helical antenna, antenna element, helical antenna, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of components for a helical antenna, and to make common a female screw part of an antenna element. <P>SOLUTION: In the structure for mounting the helical antenna, a helical antenna 1 is comprised of an antenna element 2 and a resin cover 3 which covers the element 2, a coil-like antenna part 2a of the antenna element 2 has a winding diameter and a pitch based on required electrical characteristics, a coil-like female screw part 2b has a winding diameter and a pitch corresponding to a male screw part 5 of a main body 4, the winding diameter being greater than that of the antenna part 2a, and the male screw part 5 and the female screw part 2b are screwed together to mount the helical antenna 1 on the main body 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mounting structure of a helical antenna using screwing of an internal thread composed of an antenna element, an antenna element, a helical antenna, and a manufacturing method thereof.

  There is Patent Document 1 as a known technical document related to the mounting of a helical antenna that uses a female screw formed of an antenna element. In Patent Document 1, a female screw is formed at the base end of a coiled antenna element, a male screw is formed on a base metal fitting having a mounting portion, and the male screw of the base metal fitting is screwed onto the female screw at the base end. A helical antenna for fixing an element and a base metal fitting is disclosed.

  For reference, Patent Documents 2 to 4 are publicly known technical documents related to screwing between a female screw formed of a coil and a male screw on the antenna side. In Patent Document 2, a metal wire is wound around a side portion of an antenna holder to form a male screw, and a metal wire is wound inside a mounting hole of a mobile phone to form a female screw, and the male screw and the female screw are screwed together. In addition, a configuration for attaching an antenna holder and an antenna is disclosed. Patent Document 3 discloses a configuration in which a female screw is formed by a coil portion of a coiled spring and a male screw of an antenna base is screwed and fixed. Patent Document 4 discloses a configuration in which a female screw is formed with a coil spring and a male screw is screwed onto the outer periphery of the antenna holder.

No. 8-3052 JP 2002-43814 A JP 2001-284932 A JP 2001-217625 A

  By the way, since the structure of patent document 1 is an attachment structure using the base end part of a helical antenna as a female screw, there is no need to provide a female screw separately, and although there is a merit which can reduce the number of parts of a helical antenna itself, Since the electrical characteristics of an antenna are determined by the spiral diameter and pitch of the antenna element, when a female screw is formed at the base end of the antenna element as in Patent Document 1, the diameter of the male screw to be screwed It is necessary to form the pitch together with that of the antenna element. Therefore, it is necessary to prepare male screws having various diameters and pitches corresponding to various diameters and pitches of antenna elements having various electrical characteristics. However, such diversification of members causes an increase in manufacturing processes and an increase in manufacturing costs.

  The present invention has been proposed in view of the above problems, and the helical antenna can be configured with a small number of parts and can be easily attached, and the members are made common to simplify the manufacturing process and reduce the manufacturing cost. It is an object of the present invention to provide a helical antenna mounting structure, an antenna element, a helical antenna, and a manufacturing method thereof.

  The helical antenna mounting structure according to the present invention includes a winding diameter corresponding to the male screw portion and a winding diameter corresponding to the male screw portion and a winding diameter based on required electrical characteristics, A coiled antenna element having an antenna portion having a winding diameter smaller than the diameter of the female screw portion at a pitch is attached by screwing the male screw portion and the female screw portion. In the mounted state, it is preferable that the contact surface provided on the outer periphery of the external thread portion of the main body or the fixture and the contact surface of the resin cover positioned on the outer periphery of the antenna portion are in contact with each other.

  Further, the antenna element of the helical antenna of the present invention has a coiled female screw portion and an antenna portion, and the winding diameter and pitch corresponding to the male screw portion of the main body or the fixture to which the female screw portion is screwed, and the antenna portion are required. The winding diameter and pitch are based on electrical characteristics, and the winding diameter is smaller than the winding diameter of the female thread portion.

  In addition, the helical antenna of the present invention has a coiled female screw part and an antenna part, and the winding diameter and pitch corresponding to the male screw part of the main body or the fixture to which the female screw part is screwed, the antenna part has required electrical characteristics. The antenna element has a winding diameter and pitch based on the above and a winding diameter smaller than the winding diameter of the female screw portion, and a resin cover fixed to the antenna element and covering the antenna element.

  Further, in the helical antenna of the present invention, the resin cover has an elongated cap shape, and an internal thread portion is formed in the vicinity of the opening, and the coiled internal thread portion of the antenna element is screwed into the internal thread portion of the resin cover as an external thread, The antenna element and the resin cover are fixed. That is, the inner diameter and pitch of the winding diameter of the female thread portion of the antenna element are used as a female screw, the male thread portion of the main body and the fixture are screwed together, and the outer diameter and pitch of the winding diameter of the female thread portion of the antenna element are used as a male screw. And it is set as the structure screwed to the internal thread part of a resin cover.

  Furthermore, the helical antenna of the present invention has a latching projection protruding outward at the terminal end of the female thread portion of the antenna element, and the latching projection is a female screw of the resin cover in response to rotation in the direction in which the antenna element comes off. It is characterized by being hooked to the part. Alternatively, in the helical antenna of the present invention, the winding diameter in the vicinity of the substantially end of the female thread portion of the antenna element is gradually increased toward the end, and the end of the resin cover is rotated with respect to rotation in the direction in which the antenna element comes off. It is characterized by being hooked on the female screw part.

  The helical antenna manufacturing method of the present invention includes a coiled female screw part and an antenna part, and the winding diameter and pitch corresponding to the male screw part of the main body or the fixture to which the female screw part is screwed, A method of manufacturing a helical antenna comprising an antenna element having a winding diameter and pitch based on required electrical characteristics, the winding diameter of the female screw portion being larger than the winding diameter of the antenna portion, and a resin cover covering the antenna element. A helical groove corresponding to the winding diameter and pitch of the antenna portion is formed from substantially the tip to the center, and the holding member corresponding to the winding diameter of the female screw portion or the inner diameter thereof is used as the female screw portion. Screw into the antenna element from the side, place the holding member and antenna element in the mold, and inject resin into the mold to And Kutsugae設 the amorphous form of the resin cover, characterized by withdrawing the holding member from the antenna element.

  According to the present invention, the helical antenna coil-shaped antenna element is constituted by a winding diameter and pitch female thread portion corresponding to the diameter and pitch of the male screw portion and an antenna portion having a winding diameter and pitch based on required electrical characteristics. For various antenna parts based on various electrical characteristics, the female screw part of the antenna element and the male screw part of the main body and the fixture can be made common to ensure compatibility. Therefore, the common use of the members can simplify the manufacturing process and reduce the manufacturing cost.

  In addition, by configuring the female thread portion with the antenna element and screwing and mounting with the male thread portion of the main body or the fixture, the helical antenna can be configured with a small number of parts, and can be easily mounted, and the helical antenna Can be firmly fixed to the transceiver body or the like, and for example, problems such as adhesion being lost or the resin cover idling relative to another member such as a collar can be eliminated. Furthermore, by contacting the contact surface of the resin cover with the contact surface of the main body, the rotational torque in the circumferential direction applied to the resin cover or the helical antenna can be received at the contact location, and the strength against rotation is increased. Become very expensive.

  In addition, the internal thread portion of the antenna element and the resin cover are integrally fixed by screwing or resin molding without providing an intervening member between the antenna element and the resin cover, and the internal thread portion of the antenna element and the external thread portion of the main body, etc. Due to the screwed configuration, the resin cover can be thickened at a location corresponding to the female thread portion of the antenna element to increase the strength. Furthermore, since the thickness of the resin cover can be increased, the resin cover does not bulge out due to elasticity and the antenna element is not pulled out, and the fixing strength between the resin cover and the antenna element can be increased.

  In addition, by making the winding diameter of the female screw part larger than the winding diameter of the antenna part and configuring the helical antenna with the antenna element and the resin cover that is covered, the number of parts of the helical antenna is reduced to two, Reduction and reduction of manufacturing cost can be aimed at. Furthermore, since the antenna element and the resin cover can be manufactured only by an assembling process, the manufacturing process can be further simplified and the manufacturing cost can be further reduced. It is possible to eliminate the necessity of providing a cap.

  For example, when using a resin cover with a female cap part in the vicinity of the opening in the shape of an elongated cap, simply insert the antenna element into the resin cover and screw the female thread part of the antenna element into the female screw part of the resin cover as a male screw. Can assemble a helical antenna. In addition, when the holding member is used to cover an elongated cap-shaped resin cover around the antenna element, the holding member is screwed in from the female screw side and extracted from the female screw side, so that the tip of the antenna portion is integrated. Can be closed with a resin cover, can easily cover the resin cover to manufacture a helical antenna, and eliminates the need to close the tip of the antenna part with a resin cap or the like, which is a separate member from the resin cover Therefore, the problem that the cap is removed does not occur.

  In addition, a latching protrusion provided at the end of the female threaded portion of the antenna element latches on the resin cover against rotation in the direction in which the antenna element comes off, or terminates the winding diameter in the vicinity of the substantial end of the female threaded portion of the antenna element. The antenna element is prevented from rotating and coming out of the resin cover by being configured so that the terminal end is hooked to the female screw part of the resin cover against the rotation in the direction in which the antenna element comes off. can do. Further, in the configuration in which the winding diameter in the vicinity of the end of the female thread portion of the antenna element is gradually increased toward the end, for example, it is not necessary to perform strict dimension management of the latching protrusion in mass production. The manufacturing process of the element can be further facilitated.

  In addition, the spiral groove of the holding member is screwed into the antenna portion, and the winding diameter and pitch of the antenna portion are held in a portion extending from the substantially tip of the holding member to the substantially center, and the outside of the root portion of the screwed holding member is held. By holding the winding diameter of the female screw portion with the diameter and covering the antenna element with resin molding in that state, the predetermined winding diameter and the predetermined pitch of the antenna portion and female screw portion of the antenna element are formed during resin molding. Thus, the required electrical characteristics of the helical antenna and the threaded engagement between the male screw portion and the female screw portion can be ensured.

  Below, this invention is demonstrated based on embodiment. In the present invention, the configuration of another invention or embodiment is added to each invention, the configuration of each invention is changed to the configuration of another invention or embodiment, or the configuration of each invention is included in the present invention. This includes those deleted to the extent that the partial effect of can be achieved.

  First, the helical antenna 1 of 1st Embodiment is demonstrated. The helical antenna 1 of 1st Embodiment is the structure which coat | covers the coil-shaped antenna element 2 with the resin cover 3 of the elongate cap shape with the substantially cone shape with a round tip, as shown in FIGS.

  The antenna element 2 is formed of a spiral metal wire, a coil is formed with a winding diameter and a pitch at which required electrical characteristics are obtained, and an antenna portion 2a formed from substantially the tip to substantially the center; A coil is formed with a predetermined diameter and pitch corresponding to the winding diameter and pitch of the male screw portion 6 and has a female screw portion 2b formed substantially at the rear end. The diameter of the female screw portion 2b of the antenna element 2 is larger than the winding diameter of the antenna portion 2a, and the female screw portion 2b of this example is formed at a pitch at which the coils are substantially in close contact. Further, a latching projection 2d is projected outwardly at the end 2c of the female thread portion 2b of the antenna element 2, and the latching projection 2d is formed in a substantially triangular prism shape whose surface on the spiral traveling direction side is an inclined surface. Has been.

  The elongated cap-shaped resin cover 3 is formed so that the inner diameter of the housing portion of the antenna portion 2a is slightly larger than the outer diameter of the winding diameter of the antenna portion 2a, and the antenna element 2 inserted from the opening on the bottom side is formed inside. Contained. The resin cover 3 has a female threaded portion 3a having a thread groove formed in the inner periphery near the opening, and the outer diameter portion of the wound diameter of the female threaded portion 2b of the antenna element 2 is screwed into the female threaded portion 3a with a male thread as the male thread. By doing so, the antenna element 2 to be inserted and accommodated is fixed. Further, a contact surface 3b is provided on the outer periphery of the female screw portion 3a at the end on the opening side, and the contact surface 3b is in contact with a contact surface 5b of the transceiver body 4 to be described later. .

  When the female screw portion 2b of the antenna element 2 is screwed into the female screw portion 3a of the resin cover 3 as a male screw, the antenna portion 2a of the antenna element 2 is inserted into the resin cover 3 from the opening side of the resin cover 3, and the female screw portion 2b. Is screwed into the female screw portion 3 b of the resin cover 3. At the time of the screwing, the latching protrusion 2d at the end 2c escapes in the inner diameter direction by the spring property of the antenna element 2 and the inclined surface of the locking protrusion 2d, and is smoothly screwed. In addition, after the screwing, the latching protrusion 2d is hooked on the surface of the female screw part 3a with respect to the rotation in the screwing-off direction, and the female screw part 2b is expanded in the outer diameter direction to prevent rotation. In this configuration, the female screw portion 2b of the second resin plate 2b is prevented from coming off from the female screw portion 3a of the resin cover 3 screwed as a male screw.

  Then, as shown in FIG. 2, a resin cover in which the antenna element 2 is housed in the male screw portion 5 provided in the main body 4 such as a transceiver or the male screw portion provided in the fixture to the main body 4. 3 is inserted through the opening on the bottom side of the resin cover 3, and the male screw portion 5 is screwed into and fixed to the inner diameter portion of the female screw portion 2b of the antenna element 2 screwed into the female screw portion 3a of the resin cover 3. And the helical antenna 1 composed of the resin cover 3 is attached to the main body 4 or the like. When the helical antenna 1 is attached to the main body 4 or the like, the resin is applied to the contact surface 5b provided on the outer periphery of the male screw portion 5a of the main body 4 or the contact surface provided on the outer periphery of the male screw portion of the fixture to the main body 4. The abutment surface 3b of the cover 3 abuts, and the abutment functions as a stopper for rotational torque loaded in the circumferential direction of the helical antenna 1.

  When the male screw portion 5a of the main body 4 is screwed into the female screw portion 2b of the antenna element 2, the female screw portion 2b of the antenna element 2 is screwed into the resin cover female screw portion 3a, and finally the female screw portion of the antenna element 2 is obtained. It is screwed in and fixed at a predetermined position until the tip of 2b comes into contact with the tip of the female screw portion 3a of the resin cover 3. Further, the female screw portion 2b of the antenna element 2 is formed to be slightly shorter than the female screw portion 3a of the resin cover 3b in the advancing direction, for example, by about 0.2 mm, and is screwed in until it comes into contact with the tip of the female screw portion 3a. In this case, a gap is formed between the position of the contact surface 3b in the longitudinal direction of the helical antenna 1 and the position of the rear end of the female screw portion 2b.

  Since the helical antenna 1 and the mounting structure thereof according to the first embodiment can form the helical antenna 1 with the antenna element 2 and the resin cover 3, the number of parts can be reduced. Furthermore, by making the winding diameters of the antenna portion 2a and the female screw portion 2b of the antenna element 2 independent of each other, the female screw portion 2b and the male screw portion 5 that is screwed to the female screw portion 2b can be used in common. 2a can be adapted to various frequency characteristics. Further, the female screw portion 2b has a larger diameter than the antenna portion 2a of the antenna element 2, and the antenna element 2 is inserted into the resin cover 3 having an internal shape corresponding to this, and the female screw portion 2b of the antenna element 2 is connected to the resin cover 3. The helical antenna 1 can be assembled by a simple assembling process and the helical antenna can be assembled by a simple assembling process by being screwed as a male screw and the female screw part 2b as a female screw to the male screw part 5 such as the main body 4. 1 can be attached to the main body 4 or the like.

  Further, since the female screw portion 2b and the female screw portion 3a are screwed together without using an adhesive or the like, the antenna element 2 and the resin cover 3 can be firmly fixed, and the contact between the female screw portion 2b and the female screw portion 3a can be secured. The urging force of the latching protrusion 2d serves as a stopper of the screwed antenna element 2, and the antenna element 2 screwed to the resin cover 3 can be stably held firmly at a predetermined position. Furthermore, since the female screw portion 2b of the antenna element 2 is directly screwed to the female screw portion 3a of the resin cover 3 and no separate member is provided between the resin cover 3 and the antenna element 2, the thickness of the resin cover 3 is increased. Thus, the strength can be increased. Furthermore, the gap between the position of the contact surface 3b in the longitudinal direction of the helical antenna 1 and the position of the rear end of the female screw portion 2b can prevent the contact surface 5b from biting into the antenna element 2 and applying external force. .

  Further, the helical antenna 1 is attached to the main body 4 by screwing the female screw portion 2b of the antenna element 2 firmly screwed to the resin cover 3 to the male screw portion 5a of the main body 4 without using an adhesive or another member. 4 and the like can be firmly fixed, and there is no problem that, for example, the adhesion is removed or the resin cover 3 is idle with respect to another member such as a collar. Furthermore, the female screw portion 2b of the antenna element 2 shared as the male screw and the female screw is screwed. For example, the movable female screw portion 2b is moved by the taper surface of the male screw portion 5a with respect to the force in the direction of pulling out the female screw portion 5a from the helical antenna 1. Since the diameter is enlarged and the outer thread portion 3a is strongly pressed outward, the mounting strength with respect to the force becomes very high. Further, the abutting surface 3b of the resin cover 3 that abuts and the abutting surface 5b of the main body 4 can receive the rotational torque in the circumferential direction applied to the resin cover 3, and the strength against rotation becomes very high. In addition, a strong mounting strength can be exhibited even when a soft resin is used for the resin cover 3 with such a fixed structure.

  Further, the antenna element 2 is inserted into the resin cover 3 having a corresponding internal shape, the female screw portion 2b is screwed to the resin cover 3 as a male screw, and the female screw portion 2b is connected to the male screw portion 5a of the main body 4 or the like. The helical antenna 1 can be assembled and attached in a configuration that is screwed as a female screw, and the assembly process and the attachment process can be facilitated.

  As a modification of the first embodiment, as shown in FIG. 4, instead of the configuration in which the latching protrusion 2d is formed at the terminal end 2c of the female screw part 2b of the antenna element 2, the winding around the substantially terminal end of the female screw part 2b is used. When the diameter is gradually increased toward the end 2c and no external force is applied to the end 2c of the antenna element 2 or in the vicinity thereof, the outer end of the end 2c is, for example, about 0. It is also suitable as a configuration located outward such as about 2 mm.

  When the female screw portion 2b of the antenna element 2 is screwed into the female screw portion 3a of the resin cover 3 in the modification, the vicinity of the substantially terminal end is biased in the inner diameter direction by the screwing of the female screw portion 2b and the male screw portion 3a. In addition, after the screwing, the terminal end 2c and the vicinity thereof urge the surface of the female screw part 3a outwardly with respect to the rotation in the screwing-off direction. Thus, the rotation is prevented, and the female screw portion 2b of the antenna element 2 can be prevented from coming off from the female screw portion 3a of the resin cover 3 screwed as a male screw.

  Next, the helical antenna 1 of 2nd Embodiment and its manufacturing method are demonstrated. As shown in FIG. 5, the helical antenna 1 of the second embodiment has the same basic configuration as that of the first embodiment, but the resin cover 3 is provided on the outer periphery of the antenna portion 2 a and the female screw portion 2 b of the antenna element 2. Are different in that they are integrally fixed.

  When manufacturing the helical antenna 1 of the second embodiment, the holding member 6 is inserted into the antenna element 2 as shown in FIG. The holding member 6 has an outer shape that is substantially the same shape as the space formed in the resin cover 3, and a portion that extends from substantially the tip to substantially the center is formed with substantially the same diameter as the antenna portion 2 a, and the antenna portion 2 a A spiral groove 6a corresponding to the winding diameter and pitch of the coil is formed, and the outer diameter of the root portion 6b located behind the portion corresponds to the winding diameter of the female screw portion 2b. The holding member 6 is inserted from the female screw portion 2b side of the antenna element 2, and is attached to the antenna element 2 by screwing the spiral groove 6a into the antenna portion 2a.

  Then, the holding portion 6c of the holding member 6 is fitted to the through hole 8a of the holding plate 8 having substantially the same diameter up to the position of the protruding portion 6d, and the holding member 6 and the antenna element 2 are attached to the holding plate 8 to hold the holding member 6. The antenna element 2 is disposed at a predetermined position in the cavity 7 a of the mold 7. Thereafter, the resin R is injected from the inflow path 7 b provided in the mold 7, and the resin cover 3 having a predetermined shape is formed on the substantially outer periphery of the antenna element 2. The resin cover 3 is integrally fixed to the antenna element 2 by resin molding, and covers the antenna portion 2a and the female screw portion 2b of the antenna element 2.

  In the injection molding of the resin R, it is possible to prevent the winding diameter and pitch of the antenna portion 2a and the female screw portion 2b from being changed by the flowing resin R. That is, a predetermined winding diameter and a predetermined pitch of the coil of the antenna portion 2a are maintained by screwing the spiral groove 6a of the holding member 6 having a predetermined diameter and the antenna portion 2a, and the female screw portion 2b to which the coil is in close contact is predetermined. By being disposed in contact with the outer peripheral surface of the holding member 6 having a diameter, the predetermined winding diameter of the coil of the female screw portion 2b and the predetermined pitch of the substantially closely coiled coil are maintained.

  Thereafter, the holding member 6 and the presser plate 8 are removed from the mold 7, the antenna element 2 and the resin cover 3 covering the substantially outer periphery thereof are taken out from the cavity 7 a, and the holding member 6 is extracted from the presser plate 8. Further, the holding member 6 screwed into the antenna element 2 is rotated and extracted, and the helical antenna 1 composed of the antenna element 2 and the resin cover 3 is obtained.

  Since the helical antenna 1 and the mounting structure thereof according to the second embodiment can also be constituted by the antenna element 2 and the resin cover 3, the number of parts can be reduced. Furthermore, by making the winding diameters of the antenna portion 2a and the female screw portion 2b of the antenna element 2 independent, the female screw portion 2b, the male screw portion 5 and the like screwed to the female screw portion 2b can be shared, and the antenna portion 2a. Can be adapted to various frequency characteristics. Furthermore, by screwing the holding member 6 and injection molding the resin R, the helical antenna 1 can be manufactured with a simple manufacturing process, and the required electrical characteristics of the antenna portion 2a and the male screw portion 5 and the female screw are obtained. Since the screwing of the portion 2b can be reliably realized, and the resin cover 3 is fixed to the antenna element 2 by resin molding directly, the helical antenna 1 has very high strength. Further, since the winding diameter of the female screw portion 2b is larger than the winding diameter of the antenna portion 2a, and the holding member 6 can enter and exit from the female screw portion 2b side, the resin cover 3 is integrally formed at substantially the tip of the antenna portion 2a. Can be formed.

  The present invention can be used for a helical antenna such as a transceiver and a manufacturing process thereof.

The partial cross section explanatory drawing which shows the helical antenna of 1st Embodiment, and the external thread part of a main body. The partial cross section explanatory drawing which shows the attachment state of the helical antenna of FIG. 1, and a main body. (A) is a front view which shows the antenna element of the helical antenna of 1st Embodiment, (b) is a bottom view of the antenna element of the figure (a). (A) is a front view which shows the antenna element of the modification of 1st Embodiment, (b) is a bottom view of the antenna element of the figure (a). Cross-sectional explanatory drawing explaining the formation process of the resin cover in the helical antenna of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Helical antenna 2 Antenna element 2a Antenna part 2b Female thread part 2c Terminal 2d Stop protrusion 3 Resin cover 3a Female thread part 3b Abutting surface 4 Main body 5a Male thread part 5b Abutting surface 6 Holding member 6a Spiral groove 6b Root part 7 Mold 7a Cavity 7b Inflow path 8 presser plate

Claims (8)

A male screw portion having a predetermined diameter and pitch provided on the main body or the fixture, a female screw portion having a winding diameter and pitch corresponding to the male screw portion, and a winding diameter and pitch based on required electrical characteristics, and the winding diameter of the female screw portion. A helical antenna mounting structure, wherein a coiled antenna element having an antenna portion having a smaller diameter is mounted by screwing the male screw portion and the female screw portion. The contact surface of the resin cover located in the outer periphery of the said antenna part and the contact surface provided in the outer periphery of the external thread part of a main body or a fixture in the said attachment state contact | abut. Helical antenna mounting structure. A coil-shaped female screw part and an antenna part, and the winding diameter and pitch corresponding to the male screw part of the main body or fixture to which the female screw part is screwed, and the antenna part has a winding diameter and pitch based on required electrical characteristics An antenna element for a helical antenna having a winding diameter smaller than that of the female screw portion. A coil-shaped female screw part and an antenna part, and the winding diameter and pitch corresponding to the male screw part of the main body or fixture to which the female screw part is screwed, and the antenna part has a winding diameter and pitch based on required electrical characteristics A helical antenna comprising: an antenna element having a winding diameter smaller than that of the female screw portion; and a resin cover fixed to the antenna element and covering the antenna element. The resin cover has an elongated cap shape, and an internal thread portion is formed in the vicinity of the opening. The coil-shaped internal thread portion of the antenna element is screwed into the internal thread portion of the resin cover as an external thread, and the antenna element and the resin cover The helical antenna according to claim 3, which is fixed. A latching protrusion protrudes outwardly at the terminal end of the female screw portion of the antenna element, and the latching projection is latched on the female screw portion of the resin cover in response to rotation in a direction in which the antenna element comes off. The helical antenna according to claim 4 or 5, characterized in that The winding diameter in the vicinity of the terminal end of the female thread portion of the antenna element is gradually increased toward the terminal end, and the terminal end is hooked on the female thread portion of the resin cover with respect to the rotation in the direction in which the antenna element is pulled out. The helical antenna according to claim 4 or 5, characterized in that A coil-shaped female screw part and an antenna part, and the winding diameter and pitch corresponding to the male screw part of the main body or fixture to which the female screw part is screwed, and the antenna part has a winding diameter and pitch based on required electrical characteristics A method for manufacturing a helical antenna comprising an antenna element having a winding diameter of the female screw portion larger than the winding diameter of the antenna portion and a resin cover covering the antenna element, the antenna extending substantially from the tip to the center A holding member in which a spiral groove corresponding to the winding diameter and pitch of the portion is formed and the outer diameter of the root portion corresponds to the winding diameter of the female screw portion is screwed into the antenna element from the female screw portion side, and the holding member and the antenna The element is placed in a mold, resin is injected into the mold, a resin cover having a predetermined shape is covered on the antenna element, and the holding member is attached to the antenna element. Method for producing a helical antenna, characterized in that withdrawn from the instrument.

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