Field of the Invention
The invention relates to a terminal fitting.
Related Art
A high-frequency compatible shielded cable often is routed in an automotive vehicle to transmit a high-frequency signal to a circuit board of an electrical device, such as a television or car navigation system mounted in the vehicle. For example, Japanese Unexamined Patent Publication No. 2015-162375 discloses a coaxial cable (shielded cable) with a coaxial connector (terminal fitting) mounted on an end part for connection to an electrical device. The coaxial cable includes an inner conductor terminal, an outer conductor terminal and a dielectric interposed between the inner and outer conductor terminals. The inner conductor terminal is connected to a core of the coaxial cable. The outer conductor terminal includes a hollow cylindrical portion for accommodating the dielectric and the inner conductor terminal on a front part and a shield crimping portion to be crimped to a shield conductor of the coaxial cable via a coupling on a rear part.
Crimping the shield crimping portion at a predetermined compression ratio may deform the shield conductor up or out due to bending deformation of the shield crimping portion. The shield conductor may be a braided wire formed by weaving metal strands into a net and may distort as the shield crimping portion is crimped. The compression ratio of the shield crimping portion may be reduced to prevent distortion of the braided wire. However, the reduced compression ratio may permit projecting pieces of the shield crimping portion to expand so that connection reliability for the shield conductor cannot be ensured.
The invention was completed on the basis of the above situation and aims to provide a terminal fitting capable of ensuring connection reliability and satisfactorily exhibiting a shielding function.
The invention is directed to a terminal fitting with an outer conductor including two shield crimping pieces deformable along an outer periphery of a shield layer of a shielded cable, and a cover including a surrounding portion for surrounding the shield crimping pieces along outer peripheries thereof.
The two shield crimping pieces can be crimped to the shield layer at a low compression ratio to prevent deformation and fracture of the shield layer. Thus, a shield layer in the form of a braided wire will not distort and an opening diameter can be made substantially uniform. There generally is a concern that the shield crimping pieces may open if the compression ratio is low. However, the surrounding portion of the subject invention surrounds the outer peripheries of the shield crimping pieces to suppress opening of the shield crimping pieces. As a result, the shield crimping pieces remain crimped to the shield layer and a satisfactory shielding function can be exhibited.
The two shield crimping pieces may rise from a body of the outer conductor. The surrounding portion may include two strips rising from a body of the cover and may be deformable along the outer peripheries of the shield crimping pieces. The body of the cover may cover tips of the shield crimping pieces to reliably suppress the opening of the shield crimping pieces.
The body of the outer conductor may include a locking hole, and tips of the strips may enter the locking hole to be locked to the outer conductor. Thus, the locking hole of the outer conductor reliably suppresses opening of the strip pieces and thereby further suppresses opening of the shield crimping pieces.
The terminal fitting may include an inner conductor having a center conductor crimping portion to be crimped to a center conductor of the shielded cable. The outer conductor may include a coupling, and the center conductor crimping portion may be disposed inside the coupling. The coupling may have an opening, and the cover may close the opening and electrically contact the outer conductor. Thus, a satisfactory flow of a current can be ensured and high frequency performance can be improved despite the presence of the opening. The cover functions to suppress opening of the shield crimping pieces and also functions to improve high frequency performance. Thus, the configuration of the terminal fitting can be simplified and the number of components can be reduced as compared to the case where these functions are realized by separate members.
An embodiment is described with reference to the drawings. A terminal fitting T according to this embodiment is connected to an end part of a shielded cable W and includes, as shown in
As shown in
The inner conductor 11 is formed, such as by bending a metal plate, and is configured by successively connecting a mating connecting portion 15, a tubular portion 16, a linking portion 17 and a center conductor crimping portion 18 from a front side to a rear side as shown in
The tubular portion 16 has a circular cross-sectional shape long and narrow in a front-rear direction (lateral direction of
The mating connecting portion 15 is composed of two resilient pieces 22 projecting forward from parts of the tubular portion 16 on both sides of the butting ends. The resilient pieces 22 are arranged to face each other across a slit extending in the front-rear direction and include, on tip sides, contacts 23 having inner surfaces to be brought into contact with a later-described tab 64 of the mating terminal fitting 60, and parts of the resilient pieces 22 before the contacts 23 are expanded to guide the tab 64.
The link 17 is configured as a plate connected to a part of the tubular portion 16 opposite to the butting ends and has a substantially U-shaped cross-section. The center conductor crimping portion 18 includes a center conductor-side body 24 connected to the rear end of the link 17 and two center conductor crimping pieces 25 in the form of an open barrel and projecting on both sides of the center conductor-body 24.
As shown in
As shown in
As shown in
The outer conductor 12 is formed, such as by bending a metal plate, and is configured by successively connecting the tubular portion 34, a coupling portion 35, a shield crimping portion 36, an expanded coupling portion 37 and a sheath crimping portion 38 from a front end to a rear end, as shown in
The tubular portion 34 is rounded to have a circular cross-section, and is held in a closed state by meshing projecting and recessed butting ends. The dielectric 13 is inserted into the tubular portion 34. As shown in
As shown in
The coupling portion 35 includes two side walls 42 connected to the rear ends of both side parts of the tubular portion 34. The side walls 42 are rectangular plates, connected to the sides of the tubular portion 34 across the butting ends and are arranged to face substantially in parallel along the front-rear direction. Spaces defined between the side walls 42 and between the tubular portion 34 and the shield crimping portion 36 are open toward both sides (vertical direction of
Unillustrated crimping tools (anvil, crimper) for the center conductor crimping portion 18 of the inner conductor 11 are inserted into the openings 43, 44. The openings 43, 44 include an anvil insertion opening 43 in which the center conductor-side body 24 is located, and a crimper insertion opening 44 in which tips of the center conductor crimping pieces 25 are located.
The coupling 35 includes stabilizers 78 projecting from the projecting ends of the side walls 42. The terminal fitting T is held retained in an unillustrated housing by the stabilizers 78 being locked to parts of the housing.
The shield crimping portion 36 includes two shield crimping pieces 45 and a shield-side body 46. The shield crimping pieces 45 are connected respectively to the rear ends of the side walls 42 and project in the same direction as the side walls 42 to form an open barrel. The shield-side body 46 is disposed between base end parts of the shield crimping pieces 45 and have a curved shape.
As shown in
As shown in
The sheath crimping portion 38 includes two sheath crimping pieces 81 and a sheath-side body 82. The sheath crimping pieces 81 form an open barrel connected to the rear ends of the expanded side walls 48. The sheath-side body 82 is connected to the rear end of the expanded body 49 and has a curved shape. The sheath crimping pieces 81 and the sheath-side body 82 are slightly larger than the shield crimping pieces 45 and the shield-side body 46.
As shown in
The inner conductor-side surrounding portion 83 has a curved inner conductor-side surrounding body 87 and two inner conductor-side strips 88 projecting from sides of the inner conductor-side surrounding body 87. Each inner conductor-side strip 88 is a rectangular plate with two parallel notches 89 extending in the front-rear direction on the inner surface of a projecting tip, and is bendable inward with each notch 89 as a starting point.
An insulating surrounding portion 90 made of synthetic resin is provided along the inner surface of the inner conductor-side surrounding portion 83 except tips of the inner conductor-side strips 88. As shown in
As shown in
The shield-side surrounding portion 84 includes locking pieces 96 in the form of plates partially projecting from central parts in the front-rear direction of the projecting tips of the shield-side strips 94. Each locking piece 96 is bendable with the tip side of the corresponding shield-side strip 94 as a starting point.
The link 85 is expanded gradually from the inner conductor-side surrounding portion 83 to the shield-side surrounding portion 84.
As shown in
The mating terminal fitting 60, as a connection partner of the terminal fitting T, includes a mating inner conductor 61, the mating dielectric 62, the mating outer conductor 65 and a mating cover 63 as shown in
An assembling method of the terminal fitting T including the inner conductor 11, the outer conductor 12, the dielectric 13 and the cover 14 is described below. First, the mating connecting portion 15 and the tubular portion 16 of the inner conductor 11 are inserted into the inner conductor insertion hole 26 of the dielectric 13. The link 17 and the center conductor crimping portion 18 of the inner conductor 11 then are arranged to project rearward from the rear surface of the dielectric 13.
The dielectric 13 then is inserted in the tubular portion 34 of the outer conductor 12 and is retained by locking the stepped locking portion 39 and the stepped lock receiving portion 33. A fitting space 79 is formed between the inner peripheral surface of the tubular portion 34 and the intermediate circumferential surface 32 of the dielectric 13 to receive the tubular end 66 of the mating terminal fitting 60 (see
The link 17 and the center conductor crimping portion 18 of the inner conductor 11 are arranged inside the coupling 35 of the outer conductor 12 (see
In the above state, the terminal fitting T is transported to a work site where a connecting operation to the shielded cable W is performed. In this case, both resilient pieces 22 of the inner conductor 11 are covered around by the dielectric 13 and the tubular portion 34. Thus, external matter cannot contact the resilient pieces 22 during transportation and at the work site so that the shapes of the resilient pieces 22 are maintained.
At the work site, the shielded cable W is pulled down from a state shown in
The core 51 of the shielded cable W is arranged to be supported on the center conductor-side body 24, the braided wire 53 is arranged to be supported on the shield-side body 46 and the sheath 54 thereof is arranged to be supported on the sheath-side body 82.
The anvil and the crimper of the unillustrated tools for the center conductor crimping portion are brought respectively into contact with the center conductor crimping portion 18 through the anvil insertion opening 43 and the crimper insertion opening 44. In that state, the anvil and the crimper are brought closer to each other. In this way, the center conductor crimping pieces 25 are bent to embrace the core 51 of the shielded cable W along the inner surface of the crimper and the inner conductor 11 is crimped and connected to the core 51.
The shield crimping portion 36 and the sheath crimping portion 38 are crimped by corresponding tools (anvil and crimper) from the outside of the outer conductor 12 before or after the crimping process of the center conductor crimping portion 18. In this way, the outer conductor 12 is crimped and connected to the braided wire 53 of the shielded cable W via the shield crimping portion 36 and crimped and connected to the sheath 54 of the shielded cable W via the sheath crimping portion 38.
The crimping tools bring the braided wire 53 of the shielded cable W into contact with the shield crimping portion 36 substantially along the circumferential direction at a compression ratio lower than normal and substantially uniform in the circumferential direction. Thus, the braided wire 53 is compressed gently by the shield crimping portion 36 and is maintained to have a substantially circular cross-section (see
The cover 14 subsequently is set to overlap the outer conductor 12. Then, the inner conductor-side surrounding portion 83 is inserted between the side walls 42 and the inner conductor-side surrounding body 87 substantially closes the crimper insertion opening 44 of the coupling 35 (see
In that state, unillustrated tools (anvil and crimper) contact and deform the shield-side surrounding portion 84 to a substantially circular cross-section. Simultaneously with or before or after that, unillustrated tools (anvil and crimper) contact and deform the inner conductor-side surrounding portion 83 to a substantially circular cross-section.
For the shield-side surrounding portion 84, the shield-side strips 94 are deformed arcuately along the outer peripheral surface of the shield-side body 46 and the locking pieces 96 are bent toward the locking hole 47 of the shield-side body 46. The locking pieces 96 enter one locking hole 47 from both sides to be locked to end edges of the locking hole 47 (see
For the inner conductor-side surrounding portion 83, the tools are inserted through the openings 43, 44 and the inner conductor-side strips 88 are bent arcuately inward together with the thin portions 92 of the insulating surrounding portion 90 (see
When the mating terminal fitting 60 is connected to the terminal fitting T, the tip of the dielectric 13 is fit into the fitting tube 67 of the mating dielectric 62 and the tubular end 66 of the mating outer conductor 65 is fit into the fitting space 79 of the terminal fitting T (see
The terminal fitting T described above exhibits the following effects.
After the inner conductor 11 is assembled with the outer conductor 12, the tools for the center conductor crimping portion 18 are brought into contact with the center conductor crimping portion 18 through the openings 43, 44 and the center conductor crimping portion 18 is crimped to the core 51 of the shielded cable W. Thus, assembling work is improved, and the resilient pieces 22 of the mating connecting portion 15 are covered and protected by the tubular portion 34 of the outer conductor 12, such as during transportation.
The flow of a current may be impeded there and high frequency performance may be reduced, if the openings 43, 44 are present in the outer conductor 12. However, the inner conductor-side surrounding portion 83 of the cover 14 substantially closes the openings 43, 44 and the cover 14 electrically contacts the outer conductor 12 via the connecting piece 86 and the shield-side surrounding portion 84. Thus, the flow of a shield current is ensured through the cover 14 and high frequency performance is improved.
The mating connecting portion 15 of the inner conductor 11 is not provided with a tubular part for covering the resilient pieces 22. Thus, external dimension differences between the mating connecting portion 15 and the mating terminal fitting 60 are small and a characteristic impedance is improved.
The cover 14 electrically contacts both the shield crimping portion 36 and the tubular portion 34. Thus, the shield current can flow substantially straight via the cover 14 even at a position corresponding to the coupling 35, and high frequency characteristic can be improved.
The shield crimping pieces 45 are crimped to the braided wire 53 of the shielded cable W at a low compression ratio. Thus, the braided wire 53 will not deform or fracture in a distorted manner. As a result, the shielding performance of the braided wire 53 is not reduced. Shield crimping pieces 45 could expand due to an insufficient crimping force on the braided wire 53. However, the shield-side surrounding portion 84 of the cover 14 surrounds the shield crimping pieces 45 from outside and prevent the shield crimping pieces 45 from inadvertently expanding.
The cover 14 has a function of suppressing expanding movements of the shield crimping pieces 45 and a function of improving high frequency performance. Thus, the configuration of the terminal fitting T is simplified and the number of components is reduced as compared to the case where these functions are realized by different members.
The shield-side surrounding body 95 of the cover 14 covers the tips of the shield crimping pieces 45 to suppress expanding movements of the shield crimping pieces 45.
The locking pieces 96 of the shield-side strips 94 enter the locking hole 47 of the shield-side body 46 and are locked to the outer conductor 12. Thus, expanding movements of the shield-side strips 94 are suppressed.
The insulating surrounding portion 90 is between the inner conductor-side surrounding portion 83 and the center conductor crimping portion 18 to prevent a short circuit between the inner conductor 11 and the outer conductor 12. In addition, the inner conductor-side strips 88 have the notches 89 and the insulating surrounding portion 90 has the thin portions 92. Thus, the insulating surrounding portion 90 can be bent as the inner conductor-side strips 88 are bent to improve work efficiency and to prevent damaging the insulating surrounding portion 90.
Other embodiments are described briefly below.
The coupling may include a bottom wall intersecting the both side wall portions and the anvil insertion opening may be open in a central side of the bottom wall.
The opening of the coupling may be composed of only the crimper insertion opening, and the anvil insertion opening may be closed.
The braided wire, the shield crimping portion and the shield-side surrounding portion may be deformed from the circular cross-sectional shape to such an extent that the braided wire is not excessively biased.
The mating terminal fitting may be connected directly to a shield conductive path of a printed circuit board without a shielded cable.
Number | Date | Country | Kind |
---|---|---|---|
2017-248728 | Dec 2017 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
5984701 | Sawayanagi | Nov 1999 | A |
5984710 | Kodama | Nov 1999 | A |
9450352 | Miyawaki | Sep 2016 | B2 |
20030224656 | Yoshida | Dec 2003 | A1 |
20100221949 | Okamoto | Sep 2010 | A1 |
20130171873 | Kanda | Jul 2013 | A1 |
20130224997 | Miyawaki | Aug 2013 | A1 |
20150244085 | Miyawaki | Aug 2015 | A1 |
Number | Date | Country |
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2015-162375 | Sep 2015 | JP |
Number | Date | Country | |
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20190199013 A1 | Jun 2019 | US |