JP4789787B2 - Coaxial connector - Google Patents

Description

  The present invention relates to a coaxial connector, and more particularly to a coaxial connector suitably used for wiring to an electric / electronic device of an automobile.

  2. Description of the Related Art Conventionally, connectors are used to connect wiring between electrical and electronic devices in the fields of vehicles such as automobiles, OA equipment, and home appliances. In recent years, with the increase in the frequency and speed of transmitted electrical signals, coaxial cables are often used for wiring of electrical and electronic equipment, and coaxial connectors are used to connect the coaxial cables.

  At this time, if there is a deviation in impedance between the coaxial cable to be connected and the mating coaxial connector to be fitted and the coaxial connector, the transmitted electrical signal is affected. In particular, the influence is large in a high-frequency electric signal of several GHz. Therefore, in the coaxial connector, impedance matching between the connected coaxial cable and the mating coaxial connector to be fitted is achieved.

  For example, Patent Document 1 includes a terminal fitting connected to an electric wire and a holding member that holds the terminal fitting, and a foaming ratio so that the impedance of the electric wire connected to the terminal fitting or the counterpart connector is matched. A connector in which a holding member is formed of the adjusted foam molding material is disclosed.

JP 2005-149789 A

  However, the outer conductor diameter of the inner conductor terminal of the coaxial connector is different from the outer diameter of the crimping portion connected to the signal conductor of the coaxial cable, for example, and the outer diameter of the connecting portion connected to the inner conductor terminal of the counterpart coaxial connector. In the coaxial connector, there may be a region where the ratio between the outer diameter of the inner conductor terminal and the inner diameter of the outer conductor terminal is different.

  In such a case, for example, the inner diameter of the outer conductor terminal is adjusted in accordance with the change in the outer diameter of the inner conductor terminal so that the ratio of the outer diameter of the inner conductor terminal to the inner diameter of the outer conductor terminal becomes constant. Thus, it is conceivable to match the impedance within the coaxial connector.

  However, for example, when the miniaturization of the coaxial connector is required, the size and shape of the inner conductor terminal and the outer conductor terminal may be limited. In the conventional coaxial connector, in the coaxial connector generated in such a case, In some cases, it was impossible to cope with the difference in impedance.

  The problem to be solved by the present invention is to provide a coaxial connector capable of matching the impedance of the entire coaxial connector without limitation of size and shape.

The coaxial connector according to the present invention is interposed between the inner conductor terminal connected to the signal conductor of the coaxial cable, the outer conductor terminal connected to the shield conductor of the coaxial cable, and the inner conductor terminal and the outer conductor terminal. A coaxial connector provided with a dielectric, wherein an inner / outer diameter ratio defined by a ratio between an outer diameter of the inner conductor terminal and an inner diameter of the outer conductor terminal is a region where the crimp portion of the inner conductor terminal is disposed And the region where the connection portion connected to the counterpart terminal of the inner conductor terminal is disposed, and the dielectric covers the crimping portion so that the impedance of the entire coaxial connector is matched. The gist is that the portion and the portion covering the connecting portion are formed of materials having different dielectric constants.

  At this time, it can be shown as a preferable example that the dielectric is integrally formed by multicolor molding of a plurality of materials having different dielectric constants.

  Moreover, it can be shown as a preferable example that the dielectric is formed by bonding a plurality of members formed of materials having different dielectric constants.

  According to the coaxial connector of the present invention, when there are a plurality of regions in which the ratio between the outer diameter of the inner conductor terminal and the inner diameter of the outer conductor terminal is different, a part of the dielectric has a dielectric constant different from that of the other part. Impedance can be adjusted by forming with a material, and the impedance in the whole coaxial connector can be matched. In this way, the dielectric constant of the dielectric is adjusted according to the inner / outer diameter ratio without changing the outer diameter of the inner conductor terminal or the inner diameter of the outer conductor terminal, so that the impedance of the entire coaxial connector can be reduced without restrictions on size and shape. It is possible to match.

  At this time, if the dielectric is integrally formed by multicolor molding of a plurality of materials having different dielectric constants, the number of steps for manufacturing the dielectric is small, so that the coaxial connector can be manufactured easily.

  Further, when the dielectric is formed by bonding a plurality of members formed of materials having different dielectric constants, the dielectric can be formed without considering compatibility between materials having different dielectric constants. Therefore, the application range of the material forming the dielectric can be expanded.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a coaxial connector according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a state where the male side coaxial connector and the female side coaxial connector are fitted. FIG. 3 is a diagram for explaining a method of integrally molding a dielectric by two-color molding. Hereinafter, the direction in which the mating coaxial connector is fitted will be described as the front side, and the opposite direction will be described as the rear side.

  As shown in FIG. 1, a coaxial connector 10 according to an embodiment of the present invention is attached to a terminal of a coaxial cable 20, an inner conductor terminal 12 connected to a signal conductor 22 of the coaxial cable 20, and a coaxial cable 20. The outer conductor terminal 16 is connected to the shield conductor 26, and the dielectric 14 is interposed between the inner conductor terminal 12 and the outer conductor terminal 16. A high frequency signal is transmitted to the inner conductor terminal 12 connected to the signal conductor 22 of the coaxial cable 20, and the outer conductor terminal 16 covers the periphery of the inner conductor terminal 12 and electromagnetically shields it. Is to do. The dielectric 14 is to insulate between both terminals.

  The coaxial cable 20 includes a signal conductor 22 through which an electric signal is transmitted, a shield conductor 26 that covers the outer periphery of the signal conductor 22 and electromagnetically shields the signal conductor 22, and is interposed between the signal conductor 22 and the shield conductor 26. Insulator 24 that insulates them, and sheath 28 that covers the outer periphery of shield conductor 26. The coaxial cable 20 maintains a constant ratio between the outer diameter of the signal conductor 22 and the inner diameter of the shield conductor 26 due to the coaxial structure.

  Since the coaxial cable 20 is connected to the coaxial connector 10, the insulator 24, the shield conductor 26, and the sheath 28 are peeled off in stages, and the signal conductor 22 and the shield conductor 26 are connected to the inner conductor terminal 12 and the outer conductor terminal 16. Each is exposed for connection.

  The inner conductor terminal 12 is formed into a substantially cylindrical shape by punching a conductive plate material and then bent by a press or the like. The inner conductor terminal 12 is connected to an inner conductor terminal 32 of a mating coaxial connector 30 on the other side to be described later. A signal is transferred. The inner conductor terminal 12 in this case has a so-called female terminal shape, and on the front side, a connection portion 12a that is divided in the circumferential direction by a slit in the longitudinal direction and gradually decreases in diameter toward the tip. If the connecting portion 32a of the male inner conductor terminal 32 of the male coaxial connector 30 which is the mating side is inserted into the connecting portion 12a, the outer surface of the connecting portion 32a is elastically contacted. To be connected. A crimping portion 12b is formed on the rear side of the connecting portion 12a of the inner conductor terminal 12, and is crimped to the signal conductor 22 by caulking the signal conductor 22 of the exposed coaxial cable 20.

  The outer conductor terminal 16 is formed by punching the conductive plate and then bending it with a press or the like to form a substantially cylindrical main body cylinder portion 16a that opens in the front-rear direction. Inside the main body cylinder portion 16a, An accommodation chamber 16b that can accommodate the dielectric 14 is provided. The substantially cylindrical main body cylinder portion 16a is configured with substantially the same diameter in the entire front-rear direction. A crimping part 16c that is crimped and fixed to the shield conductor 26 and the sheath 28 of the coaxial cable 20 is extended from the lower part of the rear end of the main body cylinder part 16a, and is crimped by the crimping piece 16d of the crimping part 16c. Thus, the outer conductor terminal 16 is electrically connected to the shield conductor 26 and is fixed to the sheath 28 by pressure.

  The dielectric 14 is formed of an insulating material, and is assembled between the inner conductor terminal 12 and the outer conductor terminal 16 so as to insulate the two terminals. The dielectric 14 has a front part 14a having a small diameter and a flange part 14b having a diameter larger than that of the front part 14a, and an insertion hole 14c that accommodates almost the entire inner conductor terminal 12 is provided inside. An opening is formed in the front-rear direction. At the distal end side of the front portion 14a of the insertion hole 14c, the connecting portion 32a of the male inner conductor terminal 32 of the mating male coaxial connector 30 to be inserted into the connecting portion 12a of the female inner conductor terminal 12 accommodated therein. The taper 14d is formed so as to be easily inserted. When the inner conductor terminal 12 is inserted into the insertion hole 14 c of the dielectric 14 from the rear side, the inner conductor terminal 12 is held in the dielectric 14.

  As a material for forming the dielectric 14, a molding material having a predetermined dielectric constant and excellent moldability can be used. Specific materials for forming the dielectric 14 include, for example, liquid crystal polymer (LCP), polymethylpentene (TPX), polybutylene terephthalate (TBT), syndiotactic polystyrene (SPS), acrylonitrile-butadiene-styrene copolymer. (ABS) can be exemplified.

  Various additives may be added to the material. For example, antioxidants, fillers, alumina, ceramics, glass and the like can be exemplified. Since these additives affect the dielectric constant of the dielectric 14, it is possible to adjust the dielectric constant of the dielectric 14 by adjusting the type and amount of the additive.

  The dielectric 14 has a front portion 14a covering the connecting portion 12a of the inner conductor terminal 12 and a flange portion 14b covering the crimping portion 12b of the inner conductor terminal 12, as divided by the broken line in the figure. Are formed of materials having different dielectric constants.

  For example, a material having a different dielectric constant is a material having a different resin type, a material having the same resin type and a different additive added to the resin, a different resin type, and a different additive being added to the resin. A material etc. can be illustrated. That is, the dielectric 14 may be formed by combining two types of resins having different dielectric constants, or two of the same types that have different dielectric constants by adding different additives. It may be formed by combining resins, or may be formed by combining two types of resins having different dielectric constants to which different additives are added.

  In general, if the characteristic impedance of a coaxial cable in high-frequency electrical signal transmission and the input impedance of the circuit connected to both ends of the coaxial cable do not match, signal reflection occurs, and this reflection causes noise and energy transmission. Therefore, all the impedances of the transmission circuits are designed to have the same value, which is called impedance matching (impedance matching).

  Normally, impedance is set to 50Ω, for example, to match the impedance of circuit boards and cables of electrical devices. Naturally, impedance matching is also applied to coaxial connectors used to connect coaxial cables to each other or to the board. Must have been. Therefore, even in a part of the coaxial connector, if there is a portion where the impedance with the transmission path is not matched, the transmission efficiency is reduced due to the reflection of the signal at the mismatched portion, noise generation, crosstalk generation, etc. A failure will occur.

The characteristic impedance of the coaxial connector is obtained by “inner / outer diameter ratio” and “dielectric constant of dielectric” (impedance Z = 138 / √ε _r × log (D / d), ε _r : relative dielectric constant, D: outer conductor) Terminal inner diameter, d: outer diameter of inner conductor terminal). Here, the inner / outer diameter ratio is defined by the ratio between the outer diameter of the inner conductor terminal and the inner diameter of the outer conductor terminal. By adjusting these elements, impedance matching with the coaxial cable is achieved, but the cross-sectional diameter of the crimping portion 12b after crimping of the inner conductor terminal 12 is electrically connected to the signal conductor 22 of the coaxial cable 20. Prioritizing connection reliability, the diameter is smaller than the cross-sectional diameter of the connecting portion 12a accommodated in the dielectric 14. On the other hand, in this range, the substantially cylindrical main body cylinder portion 16a of the outer conductor terminal 16 is configured with substantially the same diameter in the entire front-rear direction.

  Therefore, in the coaxial connector 10, when the impedance of the front region where the connection portion 12 a of the inner conductor terminal 12 is disposed is equal to that of the coaxial cable 20, the impedance of the rear region where the crimp portion 12 b of the inner conductor terminal 12 is disposed is coaxial. It becomes higher than the cable 20.

  In order to improve this, for example, it is conceivable to increase the sectional diameter of the crimping portion 12b of the inner conductor terminal 12 after crimping. For example, a method of separately winding a metal tape around the crimping part 12b of the inner conductor terminal 12 after crimping, or crimping a cylindrical metal sleeve from above to make it thicker, etc. can be considered. However, these methods require additional parts, and are accompanied by the addition of man-hours, devices, etc., resulting in high costs.

  In the coaxial connector 10 according to the present embodiment, the flange portion 14b of the dielectric 14 is made of a material having a dielectric constant smaller than that of the front portion 14a, and the impedance of the rear region where the crimp portion 12b of the inner conductor terminal 12 is disposed. Is matched with the front area | region where the connection part 12a of the inner conductor terminal 12 is arrange | positioned. Thereby, the impedance in the whole coaxial connector 10 is matched.

  More specifically, for example, the dielectric 14 may be configured by using SPS for the front portion 14a and using alumina-added SPS for the flange portion 14b.

  Next, a state where the male side coaxial connector 30 and the female side coaxial connector 10 are fitted will be described and described. Similarly to the female connector 10, the male coaxial connector 30 is attached to the end of the coaxial cable 20 and connected to the inner conductor terminal 32 connected to the signal conductor 22 of the coaxial cable 20 and the shield conductor 26 of the coaxial cable 20. The outer conductor terminal 36 and the dielectric 34 interposed between the inner conductor terminal 32 and the outer conductor terminal 36 are configured.

  FIG. 2 shows a structure in which the female-side coaxial connector 10 connected to the coaxial cable 20 and the male-side coaxial connector 30 connected to the coaxial cable 20 are fitted and connected. The connecting portion 32a of the male inner conductor terminal 32 of the male coaxial connector 30 is connected to the female inner conductor terminal 12 through a tapered insertion hole 14c formed at the front end side of the front portion 14a of the dielectric 14 of the female coaxial connector 10. At the same time as being inserted into the connecting portion 12 a, the dielectric 14 and the outer conductor terminal 16, where the tip of the dielectric 34 of the male coaxial connector 30 and the tip of the outer conductor terminal 36 are on the front side of the female coaxial connector 10, Is inserted in the space between.

  In the fitting portion, the connection portion 32 a of the inner conductor terminal 32 of the male side coaxial connector 30 is smaller in diameter than the connection portion 12 a of the inner conductor terminal 12 of the female side coaxial connector 10. From the distal end of the connection portion 12 a of the conductor terminal 12 to the base end of the connection portion 32 a of the male side coaxial connector 30, the outer diameter is smaller than other portions of the inner conductor terminal 32. Moreover, since the front-end | tip part of the outer conductor terminal 36 of the male side coaxial connector 30 is in the inner side of the female side coaxial connector 10, in the fitting part, the internal diameter of the outer conductor terminal 36 of the male side coaxial connector 30 is inner and outer diameter. It becomes the inner diameter of the ratio.

  Here, the area A, the area B, and the area C have different inner and outer diameter ratios. In the region B to be the fitting portion, the outer diameter decreases from the distal end of the connecting portion 12a of the inner conductor terminal 12 of the female side coaxial connector 10 to the base end of the connecting portion 32a of the male side coaxial connector 30, and the male side coaxial. In consideration of the fact that the inner diameter of the outer conductor terminal 36 of the connector 30 becomes the inner diameter of the inner / outer diameter ratio, the front portion 14 a of the dielectric 14 of the female coaxial connector 10 and the front portion of the dielectric 34 of the male coaxial connector 30. A material having a dielectric constant such that the impedance in the region B is equal to the impedance in the coaxial cable 20 may be used as the material 34a.

  Then, in the male side region A, the inner diameter of the inner / outer diameter ratio is the same as that of the region B, but the outer diameter is reduced in the crimping part 32b. The rear portion 34b may be made of a material having a smaller dielectric constant than the material of the front portion 34a so that the impedance of the entire male coaxial connector 30 is matched.

  Further, in the region C on the female side, the flange portion 14b of the dielectric 14 is connected to the front portion 14a in consideration of the fact that the inner diameter of the inner / outer diameter ratio is larger than that of the region B and the outer diameter is reduced in the crimping portion 12a. It is preferable to match the impedance of the entire coaxial connector 10 by using a material having a dielectric constant smaller than that of the material.

  As a method of forming the dielectric body 14, for example, a method of integrally forming by two-color molding of two kinds of materials having different dielectric constants, or two members formed of materials having different dielectric constants are bonded together. There are methods. The former method has an advantage that the number of steps for manufacturing the dielectric 14 can be reduced, and the latter method does not need to consider the compatibility between the materials forming the member to be bonded. There is an advantage of wide application range.

  The two-color molding of the dielectric 14 is preferably performed using, for example, a two-color molding die shown in FIG. The two-color molding die is composed of a lower die 40, a first upper die 42, and a second upper die 44. The upper molds 42 and 44 are movable types that can be moved up and down, but the lower mold 40 may be a fixed type or a movable type. In the case of the movable type, it is preferable that the lower position of the first upper mold 42 and the lower position of the second upper mold 44 can be reciprocated. In the two-color mold, the lower mold 40 and the first upper mold 42 form a first cavity 46 that is filled with one material to form the flange portion 14b. Thus, the second cavity 48 that forms the front portion 14a by filling with another material is formed.

  In order to mold the dielectric 14 in two colors, as shown in FIG. 3A, the lower mold 40 is placed under the first upper mold 42 and clamped, and the lower mold 40, the first upper mold 42, The flange portion 14b is formed by filling one material into the first cavity 46 formed in the above. Next, as shown in FIG. 3B, the lower mold 40 and the first upper mold 42 are opened. Next, as shown in FIG. 3 (c), with the flange portion 14b formed of one material being placed, the lower die 40 is placed under the second upper die 44 and clamped to form the second cavity. 48 is formed. The second cavity 48 is filled with another material to mold the front portion 14a. Next, as shown in FIG. 3D, the lower mold 40 and the second upper mold 44 are opened, and the two-color molded dielectric 14 is taken out from the molds 40 and 44. If the lower mold 40 is moved to the lower part of the first upper mold 42 after being taken out from the molds 40, 44, the next dielectric 14 can be molded in two colors.

  Alternatively, a method may be used in which a pair of upper molds and lower molds are used, and two materials are filled in a cavity formed by the upper mold and the lower mold. In this case, two-color molding can be performed by using two layers in the cavity by utilizing the difference in specific gravity between the two materials. Further, it may be composed of a set of upper and lower molds, and the central part of the upper mold may be operated. In this case, when one material is filled, the shape is as shown in FIG. 3A, and then the central portion of the upper mold is raised to form the second cavity 48 as shown in FIG. It is better to configure.

  When the dielectric 14 is integrally formed by two-color molding, it is more preferable to use two types of materials having the same dielectric constant and different additives as the two types of materials having different dielectric constants, because the compatibility between the resins is excellent. .

  On the other hand, in the method of forming the dielectric 14 by bonding two members together, for example, the front part 14a and the flange part 14b are respectively formed by separate molds, and then the front part 14a and the flange part are bonded with an adhesive or the like. 14b may be pasted together.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, in the above-described embodiment, as the plurality of regions having different inner / outer diameter ratios, the region where the crimp portion of the inner conductor terminal is disposed and the region where the connection portion of the inner conductor terminal is disposed are described. However, it is not particularly limited to these regions. This is because various cases are conceivable depending on the size and shape of the designed inner conductor terminal and outer conductor terminal. Further, the plurality of regions are not limited to two regions, but may be three or more regions. In this case, the dielectric may be made of three or more materials having different dielectric constants.

  The coaxial connector according to the present invention can be suitably used, for example, for wiring to electric / electronic devices of automobiles.

It is sectional drawing showing the coaxial connector which concerns on 1st embodiment of this invention. It is sectional drawing showing the state by which the male side coaxial connector and the female side coaxial connector were fitted. It is a figure explaining the method of integrally forming a dielectric material by two-color molding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Coaxial connector 12 Inner conductor terminal 12a Connection part 12b Crimp part 14 Dielectric 14a Front part 14b Flange part 16 Outer conductor terminal 20 Coaxial cable

Claims (3)

A coaxial connector comprising an inner conductor terminal connected to a signal conductor of a coaxial cable, an outer conductor terminal connected to a shield conductor of the coaxial cable, and a dielectric interposed between the inner conductor terminal and the outer conductor terminal Because
The inner / outer diameter ratio defined by the ratio between the outer diameter of the inner conductor terminal and the inner diameter of the outer conductor terminal is connected to the region where the crimp portion of the inner conductor terminal is disposed and the counterpart terminal of the inner conductor terminal It is different in the area where the connected part is arranged,
The dielectric is characterized in that a portion covering the crimping portion and a portion covering the connecting portion are formed of materials having different dielectric constants so that impedances in the entire coaxial connector are matched. Coaxial connector. The coaxial connector according to claim 1 , wherein the dielectric is integrally formed by multicolor molding of a plurality of materials having different dielectric constants. The coaxial connector according to claim 1 , wherein the dielectric is formed by bonding a plurality of members formed of materials having different dielectric constants.

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