# Patent

## Title
Coaxial connector including crimp housing

## Abstract

The present invention provides a coaxial connector capable of reducing harness processing steps. A coaxial connector includes a contact by three-point contact, a housing including a first and a second connection base, and a shell including a cylindrical portion accommodating the first connection base and an extension portion accommodating the second connection base. The central conductor of a cable is placed on an installation surface of a contact located in a predetermined part of a housing, and a crimp housing with a slot cut out to allow pressure on the periphery of the center conductor is used. The crimp housing is held in the housing and enclosed and tightened by a pair of crimp barrels (the first barrel) provided in the shell. This allows the central conductor to be securely crimped to the installation surface of the contact.

## Background
This application is based on and claims the benefit of priority from Japanese Patent Application No. 2021-035612, filed on 5 Mar. 2021, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an electrical connector. In particular, the present invention relates to a small-sized coaxial connector configured on an end of a coaxial cable and to a structure of the coaxial connector including a shell electrically connected to an external conductor of the coaxial cable on one end side and formed in a cylindrical shape on the other end side.
Related Art
The coaxial connector fixed to the terminal of the coaxial cable is connected to a receptacle mounted on a printed circuit board, and thus a high frequency signal can be transmitted from the coaxial cable to the printed circuit board. Alternatively, the high frequency signal can be transmitted from the printed circuit board to the coaxial cable.
In general, the coaxial cable is configured by a circular central conductor, a dielectric surrounding the central conductor, an external conductor such as a braided wire surrounding the dielectric, and an insulating sheath covering and protecting the external conductor.
For example, a coaxial connector according to the conventional technology undergoes the following processes: “coaxial cable constant dimension cutting”→“coaxial cable terminal treatment (cable stripping)”→“(shell bending)+(housing lid closing)+(central conductor insulation displacement contacting)”→“external conductor crimping” to complete the harness (refer to, for example, Japanese Unexamined Patent Application, Publication No. 2019-220253).
A description will be given of a series of assembling process of “(shell bending)+(housing lid closing)+(central conductor insulation displacement contacting)” in Japanese Unexamined Patent Application, Publication No. 2019-220253. A lid housing is accommodated within a cylindrical portion of the shell connecting the cable clamp. The cable clamp has a pair of crimp barrels, a pair of conductor barrels, and a pair of insulation barrels extending in a direction orthogonal to its longitudinal direction. The lid housing has a structure for accommodating and securing the end of a terminalized coaxial cable with contacts housed thereinside. The contact includes insulation-displacement edge that can be insulation-displacement connected to the central conductor of the end of the coaxial cable. The lid housing includes a bendable lid. This lid can be bent together according to the bending of the cable clamp of the shell that is placed behind during the assembly process. Once the end of the coaxial cable is contained in the lid housing, the lid of the lid housing can be bent along with the bending of the cable clamp of the shell to press against the end of the coaxial cable (the dielectric covering the central conductor). This results in an insulation-displacement connection of the central conductor to the insulation-displacement edge of the contact.
The cable clamp of the shell is further tightened by a pair of crimped barrels that wrap around the lid housing. This maintains the insulation-displacement connection of the central conductor to the contact. The cable clamp of the shell is further crimped to the external conductor by a pair of conductor barrels. This creates an electrical connection between the external conductor and the shell. The cable clamp of the shell further crimps a pair of insulation barrels to the insulation sheath. This secures the coaxial connector to the end of the coaxial cable.
According to Japanese Unexamined Patent Application, Publication No. 2019-220253, the process of bending the cable clamp together with the lid of the lid housing, and then tightening the pair of crimp barrels to the lid housing to put the central conductor in a state to be wired, it still requires a lot of harness processing steps, and thus, there is room for further simplification. In addition, it is not easy to reduce the manufacturing cost of harnesses that go through such processing steps.
SUMMARY OF THE INVENTION
The present invention has been made in view of such a circumstance, and it is an object of the present invention to provide a coaxial connector capable of reducing harness processing steps.
The invention includes a configuration in which the central conductor of a cable is placed on an installation surface of a contact located in a predetermined part of a housing, and a crimp housing with a slot cut out to allow pressure on the periphery of the center conductor is used. The crimp housing is held in the housing and enclosed and tightened by a pair of crimp barrels (the first barrel) provided in the shell. This allows the central conductor to be securely crimped to the installation surface of the contact. Based on this configuration, the harness processing process can be reduced compared to the conventional process.
(1) A coaxial connector according to an embodiment of the present invention is a coaxial connector configured on an end of a coaxial cable including a central conductor, a dielectric surrounding the central conductor, an external conductor that covers the dielectric, and an insulating sheath that clads the external conductor, the coaxial connector including: a contact capable of being connected to a cylindrical mating contact, the contact including a pair of fixed terminals and a movable terminal, the terminals being erected from a tip end side of a strip-shaped metal plate and being capable of externally contacting the mating contact by three-point contact; a housing including a first connection base and a second connection base, the first connection base including an accommodation space in which one surface side is open such that the mating contact is insertable and the pair of fixed terminals and the movable terminal are disposed inside, the second connection base partially protruding from the first connection base; a conductive shell including a cylindrical portion that is open to the one surface side and is provided to surround the first connection base, and an extension portion at least including a gutter-shaped that is coupled to the cylindrical portion and is capable of accommodating the second connection base therein; and a crimp housing including a slot that is notched so as to be capable of pressing an outer periphery of the central conductor and capable of being inserted from an opening side of the accommodation space toward a predetermined portion of the second connection base, wherein the contact includes an installation surface in which a base end side of the metal plate is exposed on a predetermined surface of the second connection base, the installation surface being capable of coming into contact with the central conductor, and wherein the extension portion of the shell includes a pair of first barrels capable of pressing the crimp housing against the second connection base, and a pair of second barrels capable of crimping the external conductor.
(2) Preferably, a pair of lances disposed across straddle the slot are provided at one end of the crimp housing, and a pair of steps that can be engaged with the pair of lances is formed at a predetermined portion of the second connection base.
(3) Preferably, the pair of fixed terminals are located at a set of vertices among vertices of a virtual equilateral triangle inscribed in the mating contact, and the movable terminal is located at the other vertex of the virtual equilateral triangle, and is disposed in a state of facing an intermediate portion of the pair of fixed terminals.
(4) Preferably, the contact is molded integrally with the housing, and includes at least: an installation surface in which a base end side of the metal plate is exposed on a predetermined surface of a part of the second connection base, the installation surface being capable of coming into contact with the central conductor; and contact edges of the pair of fixed terminals, the contact edges being exposed to the accommodation space and capable of coming into contact with the mating contact.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a configuration of a coaxial connector according to an embodiment of the present invention, and is an external view of the coaxial connector configured on an end of a coaxial cable in which a mating coaxial connector is disposed so as to face when viewed from an upper surface side;
FIG. 2 shows the configuration of the coaxial connector according to the embodiment, and is an external view of the coaxial connector configured on the terminal of the coaxial cable when viewed from a lower surface side;
FIGS. 3A and 3B are views showing the configuration of the coaxial connector according to the embodiment, wherein FIG. 3A is a bottom view showing the coaxial connector configured on the terminal of the coaxial cable, and FIG. 3B is a right side view of FIG. 3A;
FIG. 4 is a cross-sectional view taken along a line X-X of FIG. 3A showing the configuration of the coaxial connector according to the embodiment;
FIG. 5 shows the configuration of the coaxial connector according to the embodiment, and is an external view corresponding to FIG. 2 showing a state before the terminal of the coaxial cable is crimped;
FIG. 6 is a perspective exploded assembly view showing the configuration of the coaxial connector according to the embodiment;
FIG. 7 shows a configuration of a housing provided in the coaxial connector according to the embodiment, and is an external view showing individually the contact and the housing to be integrally molded;
FIGS. 8A and 8B are views showing the configuration of the housing provided in the coaxial connector according to the embodiment, wherein FIG. 8A is a plan view showing an upper surface of the housing, and FIG. 8B is a plan view showing a lower surface of the housing;
FIG. 9 is a cross-sectional view taken along a line A-A of FIG. 4 showing the configuration of the coaxial connector according to the embodiment;
FIG. 10 is an external view showing a configuration of a crimp housing provided in the coaxial connector according to the embodiment;
FIGS. 11A and 11B are each front views showing the configuration of the crimp housing provided in the coaxial connector according to the embodiment, wherein FIG. 11A shows a state before the crimp housing is completely attached to the housing, and FIG. 11B shows a state where the crimp housing is completely attached to the housing; and
FIG. 12 is an external view showing an assembly process of the coaxial connector according to the embodiment.



DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
Configuration of Coaxial Connector
First, a configuration of a coaxial connector according to an embodiment of the present invention will be described.
Overall Configuration
With reference to FIGS. 1 to 6, a coaxial connector (hereinafter, also referred to as a plug) 10 according to an embodiment of the present invention is configured on an end of a coaxial cable Cb. The coaxial cable Cb includes a central conductor Wc, a dielectric Di surrounding the central conductor Wc, an external conductor Wb such as a braided wire that covers the dielectric Di, and an insulating sheath Wi that clads the external conductor Wb.
The coaxial plug 10 includes a contact 1 by a three-point contact, a housing 3 including first and second connection bases, and a conductive shell 5. Further, the housing 3 includes a block-shaped crimp housing 7. Further, the shell 5 includes a pair of first barrels 521 and 521 and a pair of second barrels 522 and 522.
The contact 1 can electrically connect a cylindrical central contact 2, which is a mating contact, and the central conductor Wc of the coaxial cable Cb (see FIG. 1).
Referring to FIG. 7, the contact 1 includes a strip-shaped metal plate 11t having an installation surface 321 at a base end, a pair of fixed terminals 11s and 11s and a movable terminal 12s on a tip end side of the metal plate 11t. The pair of fixed terminals 11s and 11s and the movable terminal 12s are erected from the tip end side of the metal plate 11t. In other words, the pair of fixed terminals 11s and 11s and the movable terminal 12s are respectively formed by a portion of the metal plate bent in a direction substantially perpendicular from an extending plane of the metal plate 11t. The central contact 2 can be inserted into a space surrounded by the pair of fixed terminals 11s and 11s and the movable terminal 12s (see FIG. 1).
The pair of fixed terminals 11s and 11s are disposed to face each other in a direction substantially orthogonal to a longitudinal direction in which the metal plate lit extends. The movable terminal 12s that can be elastically deformed is a plate spring terminal disposed in a state of facing an intermediate portion of the pair of fixed terminals 11s and 11s. When the central contact 2 is inserted into the space surrounded by the pair of fixed terminals 11s and 11s and the movable terminal 12s, the pair of fixed terminals 11s and 11s and the movable terminal 12s can externally contact an outer periphery of the central contact 2 by three-point contact.
Referring to FIGS. 2 to 6, the contact 1 is molded integrally with the housing 3. The installation surface 321 of the contact 1 is exposed onto a connection surface 32c provided at a position come down by one step from an upper surface of a second connection base 32 to be described below, and can come into contact with the central conductor Wc. The central conductor Wc is placed on the installation surface 321, and can be reliably electrically connected to the contact 1 by the crimp housing 7 pushed down toward the housing 3.
Referring to FIG. 6 to FIGS. 8A and 8B, the housing 3 includes a first connection base 31 having a disk portion and a second connection base 32 having a complex rectangular portion. The second connection base 32 has a shape that partially protrudes from the disk portion of the first connection base 31. The first connection base 31 includes an accommodation space 31r in a center of the disk portion (see FIG. 2 or 3).
Referring to FIG. 2 or FIGS. 3 and 5, the accommodation space 31r has a form in which one surface of the housing 3 is opened such that the central contact 2 can be inserted. The accommodation space 31r is formed in a substantially rectangular shape, and is disposed with the pair of fixed terminals 11s and 11s and the movable terminal 12s therein. The accommodation space 311 includes a pair of gaps 31g and 31g that are inclined from the rectangular region and extend outward from each other (see FIG. 9). Thus, the accommodation space 31r has a shape similar to a plus (+) on an upper surface of the disk portion of the first connection base 31. This is one of configurations for the purpose of measures against deformation and maintenance of elasticity according to various environments of the disk portion or the accommodation space 31r of the first connection base 31.
Referring to FIG. 5, the shell 5 includes a cylindrical portion 51 and an extension portion 52. The cylindrical portion 51 is configured to surround the disk portion of the first connection base 31. The cylindrical portion 51 can accommodate the first connection base 31 of the housing 3.
An external contact 6 of a mating connector 20 to be described below can be inserted inside the cylindrical portion 51 (see FIG. 1). When the external contact 6 is inserted inside the cylindrical portion 51, the shell 5 and the external contact 6 can be electrically connected. Further, the contact 1 and the central contact 2 can be electrically connected.
Referring to FIGS. 1 to 6, the extension portion 52 is configured to be coupled to the cylindrical portion 51. The extension portion 52 has a gutter-shaped configuration to be coupled to a part of the outer periphery of the cylindrical portion 51 and to extend away from the outer periphery of the cylindrical portion 51. Then, the extension portion 52 can accommodate the second connection base 32 of the housing 3 therein (see FIG. 2 or 5). Further, the extension portion 52 acts on fixing of the coaxial cable Cb.
More specifically, the extension portion 52 includes a pair of first barrels 521 and 521 and a pair of second barrels 522 and 522. The pair of first barrels 521 and 521 can press the crimp housing 7 against the second connection base 32, and thus can crimp the central conductor Wc of the coaxial cable Cb against the installation surface 321 of the contact 1. The pair of second barrels 522 and 522 can crimp the external conductor Wb from above the dielectric Di.
When the pair of second barrels 522 and 522 crimp the external conductor Wb surrounding the dielectric Di, the external conductor Wb and the shell 5 can be electrically connected. Thereby, the coaxial plug 10 can be fixed to the terminal of the coaxial cable Cb.
Referring to FIGS. 1 to 6, the extension portion 52 further includes a bottom plate piece 52b that covers an opening of the cylindrical portion 51 on the other surface of the housing 3. In other words, the first connection base 31 constituting the disk portion is accommodated by the bottom plate piece 52b and the cylindrical portion 51.
Referring to FIG. 4, the bottom plate piece 52b has an inclined surface which is higher on a side on which the first and second barrels (521, 522) of the extension portion 52 are formed and is lower on the tip end of the coaxial connector 10.
Configuration of Mating Connector
Next, a description will be given with reference to FIG. 1 with respect to a configuration of a receptacle (mating connector) 20 to which the coaxial plug 10 according to the embodiment is connected. The receptacle 20 according to the embodiment is surface-mounted on a printed circuit board (not shown). The receptacle 20 includes a cylindrical central contact 2 having a closed tip end, a housing 4 made of a dielectric, and an annular external contact 6.
The central contact 2 is related to a main body 21 formed on a concentric circle of the central contact and a lead terminal 2r of the central contact 2, and the lead terminal 2r can be soldering-joined to a signal pattern in a wiring pattern of the printed circuit board (not shown). The external contact 6 is related to a main body 61, which is formed on the concentric circle of the main body 21 and has an opened upper surface, and a lead terminal 6r of the external contact 6, and the lead terminal 6r can be soldering-joined to a ground pattern in the wiring pattern of the printed circuit board (not shown).
The housing 4 is formed in a shape of a rectangular plate. The central contact 2 and the external contact 6 are integrally molded by the housing 4, and thus the central contact 2 and the external contact 6 are fixed to each other. A dielectric material is abundant inside the housing 4, and the central contact 2 and the external contact 6 are electrically insulated from each other.
When the coaxial plug 10 is connected to the receptacle 20, the central conductor Wc existing in the coaxial cable Cb can be connected to the central contact 2, and the external conductor Wb existing in the coaxial cable Cb can be connected to the external contact 6. Thereby, it is possible to transmit a high frequency signal from the coaxial cable Cb to the printed circuit board, and to transmit a high frequency signal from the printed circuit board to the coaxial cable Cb.
Configuration of Contact
A configuration of the contact 1 according to the embodiment will be described below with reference to FIGS. 7 and 3A and FIG. 8B. As the contact 1, it is possible to obtain the contact 1 having a desired shape by three-point contact by punching and bending a conductive metal plate. The contact 1 is preferably made of a copper alloy, bit is not limited to the copper alloy.
The pair of fixed terminals 11s and 11s are located at a set of vertices, among vertices of a virtual equilateral triangle inscribed in the central contact 2. On the other hand, the movable terminal 12s is located at the other vertex of the virtual equilateral triangle. Then, the contact surface of the movable terminal 12s is disposed in a state of facing the intermediate portion of the pair of fixed terminals 11s and 11s. More specifically, the movable terminal 12s is disposed in a state of being elastically deformed in a direction along a straight line passing through the vertex of the virtual equilateral triangle, at which the movable terminal 12s is located, and the intermediate portion of the pair of fixed terminals 11s and 11s. 
When the central contact 2 of the receptacle 20 is inserted into the accommodation space 31r of the first connection base 31, the outer periphery of the central contact 2 comes into contact with ridge portions (contact edges) of the pair of fixed terminals 11s and 11s located in the accommodation space 31r and comes into contact with the movable terminal 12s. In this way, the contact 1 can make three-point contact with the central contact 2.
Configuration of Housing
A configuration of the housing 3 according to the embodiment will be described below with reference to FIG. 2 to FIGS. 8A and 8B. The housing 3 is preferably made of an insulating synthetic resin, and the insulating synthetic resin can be molded to obtain the housing 3 having a desired shape.
Referring to FIG. 4, the coaxial plug 10 is configured such that a distance from the contact 1 (metal plate lit) to the bottom surface of the shell 5 is substantially equal at the tip end side and the base end side of the contact 1. In order to contribute to such a feature, the bottom plate piece 52b of the cylindrical portion 51 has the inclined surface as described above.
More specifically, the housing 3 is formed so that a difference between a distance D2 from the tip end side of the contact 1 to the bottom surface of the shell 5 and a distance D1 from the base end side of the contact 1 to the bottom surface of the shell 5 is made as small as possible. A thickness of the housing 3 is substantially the same on the tip end side and the base end side of the contact 1. In other words, there is a relation of D2≈D1.
On the tip end side and the base end side of the contact 1, it is possible to inhibit disturbance of impedance by making the difference small between the distance from the tip end side of the contact 1 (metal plate 11t) to the shell 5 and the distance from the base end side of the contact 1 to the shell 5. Thereby, it is possible to increase a high frequency band of the high frequency signal transmitted to the coaxial plug 10. For example, VSWR (voltage standing wave ratio) can be inhibited to less than “1.5” up to 60 GHz.
Configuration of Shell
A configuration of the shell 5 according to the embodiment will be described below with reference to FIGS. 1 to 6. As the shell 5, it is preferable to obtain the shell 5 having a desired shape by molding a deployable plate having conductivity such as a metal plate processed into a predetermined outer shape. The shell 5 preferably includes a cylindrical portion 51 and an extension portion 52 that has at least a gutter-shaped.
In the extension portion 52, the pair of first barrels 521 and 521 and the pair of second barrels 522 and 522 are preferably bent and shaped in a state of being open. Further, the bottom plate piece 52b of the cylindrical portion 51 is preferably shaped in the extension portion 52.
The pair of first barrels 521 and 521 can be bent to enclose the crimp housing 7 attached to the second connection base 32. When the crimp housing is pressed by the pair of first barrels 521 and 521, the central conductor Wc placed on the installation surface 321 of the second connection base 32 can be firmly crimped to the installation surface 321.
The pair of second barrels 522 and 522 can be bent to enclose the external conductor Wb surrounding the dielectric Di. Thus, the pair of second barrels 522 and 522 are crimped to the external conductor Wb to electrically connect the external conductor Wb and the shell 5 to each other and to fix the coaxial connector 10 to the terminal of the coaxial cable Cb.
Configuration of Crimp Housing
Next, referring to FIGS. 6, 9, 10 and FIGS. 11A and 11B, a configuration of the crimp housing 7 according to the embodiment will be described. The crimp housing 7 includes a slot 7s notched in a U shape. The slot 7s is formed so as to be capable of pressing the outer periphery of the central conductor Wc. The crimp housing 7 can be inserted from the opening side of the accommodation space 31r toward a predetermined portion of the second connection base 32. The predetermined portion has, for example, a configuration for holding the crimp housing 7 in the second connection base 32.
One end of the crimp housing 7 is provided with a pair of lances 7r and 7r. The pair of lances 7r and 7r are disposed across straddle the slot 7s. A pair of guide grooves 7g and 7g are provided between each of the pair of lances 7r and 7r and the slot 7s. A pair of notches 7n and 7n are provided between the guide grooves 7g and 7g and the lances 7r and 7r, respectively. Thereby, deformation accompanied by elasticity is allowed at peripheral parts of the lances 7r and 7r. 
On the other hand, referring to FIG. 6 or 7, a pair of steps 32d and 32d are formed in the second connection base 32 of the housing 3 so as to be capable of engaging with the pair of lances 7r and 7r of the crimp housing 7. Further, a pair of raised portions 32e and 32e for pressing are formed inside the pair of steps 32d and 32d so as to be inclined and raised from base ends of the steps 32d and 32d. Positioning projections 32p and 32p are formed between the pair of steps 32d and 32d and the raised portions 32e and 32e and the connection surface 32c. When the crimp housing 7 is pushed into the second connection base 32 through fitting of the guide grooves 7g and 7g and the projections 32p and 32p, the lances 7r and 7r are engaged with the steps 32d and 32d. Thus, the crimp housing 7 is held by the second connection base 32.
Referring to FIG. 11A, a state is shown in which the central conductor Wc is placed on the installation surface 321 and the crimp housing 7 is held by the second connection base 32. In such a state, the slot 7s of the crimp housing 7 does not press the central conductor Wc. Next, referring to FIG. 11B, the pair of first barrels 521 and 521 are bent processed to enclose the crimp housing 7. Thereby, the central conductor Wc on the installation surface 321 is pressed by the slot 7s, and the central conductor Wc is crimped to the installation surface 321. At this time, the pair of lances 7r and 7r of the crimp housing 7 move from the pair of steps 32d and 32d and are located in a plane regions of the raised portions 32e and 32e, respectively. Thereby, due to the deformation around the lances 7r and 7r on which the pair of notches 7n and 7n act, the crimp housing 7 is firmly positioned through the fitting of the guide grooves 7g and 7g and the projections 32p and 32p of the second connection base 32. As a result, the central conductor Wc can be connected to the contact 1.
In the coaxial plug 10 according to the embodiment, the central conductor Wc is pressed against and crimped to the installation surface 321 using the crimp housing 7 and the pair of first barrels 521 and 521 that press the crimp housing 7. Thus, the central conductor Wc is reliably bonded to the contact 1.
Operational Effects of Coaxial Connector
With reference to FIG. 12, while explaining the assembly process of the coaxial connector 10 according to the embodiment, the operation and advantageous effect of the coaxial connector 10 according to the embodiment will be described.
With the pair of first barrels 521 and 521 and the second pair of barrels 522 and 522 unfolded (refer to FIG. 5), and with a part of the bottom of the pair of second barrels 522 and 522 connected to the carrier C of the metal plate, the housing 3 with the contact 1 is placed on the shell 5 in the expanded state, and assembled. The crimp housing 7 is also held in the second connection base 32 (refer to FIG. 11A).
Next, the central conductor Wc of the terminated coaxial cable Cb is placed on the installation surface 321 (refer to FIG. 8B), and the external conductor Wb of the terminal processed coaxial cable Cb is placed on the bottom of the second barrel 522 and 522 (refer to FIG. 5).
With respect to the crimp housing 7, the pair of first barrels 521 and 521 are bent from the state shown in FIG. 11A so as to wrap around the second connection base 32 (FIG. 11B). This causes the central conductor Wc to be pressed against the installation surface 321 by the crimp housing 7, and the central conductor Wc can be securely connected to the contact 1.
Also, the pair of second barrels 522 and 522 are bent so that they wrap around the external conductor Wb that surrounds the dielectric Di. As a result, the pair of second barrels 522 and 522 are crimped to the external conductor Wb to electrically connecting the external conductor Wb to the shell 5, and fixing the coaxial plug (coaxial connector) 10 to the terminal of the coaxial cable Cb. It should be noted that the timing for detaching the shell from the carrier C can be changed depending on the environment of the assembly process.
As described above, a series of assembly processes are accomplished. The coaxial plug 10 according to the embodiment can be used to press the crimp housing 7 held on the second connection base 32 by the pair of first barrels 521 and 521 without undergoing the process of bending the cable clamp. This allows the central conductor Wc placed on the installation surface 321 to be crimped so that the central conductor We can be securely connected to the contact 1. As a result, it is possible for the coaxial plug 10 according to the embodiment to reduce the harness processing process, which can contribute to the reduction of the manufacturing cost.
Referring to FIGS. 1 to 9, the coaxial plug 10 according to the embodiment includes a three-point contact type contact 1 that externally contacts the central contact 2 by three-point contact. The three-point contact type contact 1 is configured by the pair of fixed terminals located at a set of vertices among vertices of the virtual equilateral triangle inscribed in the central contact 2 and the movable terminal located at the other vertex. The elastic displacement of the movable terminal is mainly within the direction toward the intermediate portion of the pair of fixed terminals and the opposite direction. This makes it possible to make the connector smaller than a coaxial connector using a two-point contact type contact that requires the terminals to spread in the direction away from each other.
Referring to FIG. 4, in the coaxial plug 10 according to the embodiment, it is possible to inhibit disturbance of impedance by making the difference (difference between D2 and D1) small between the distance from the tip end side of the contact 1 (metal plate lit) to the shell 5 and the distance from the base end side of the contact 1 to the shell 5. Thereby, it is possible to increase the high frequency band of the high frequency signal transmitted to the coaxial plug 10.
Referring to FIGS. 11A and 11B, from the state in which the central conductor Wc is placed on the installation surface 321 and the crimp housing 7 is held by the second connection base 32, the central conductor Wc is crimped to the installation surface 321 through the pair of first barrels 521 and 521 and the crimp housing 7. In other words, the central conductor Wc is connected to the contact 1 by pressing the outer periphery of the central conductor Wc facing the installation surface 321 with the bottom of the slot 7s. 
While preferred embodiments of the present invention have been described and illustrated above, it is to be understood that they are exemplary of the invention and are not to be considered to be limiting. Additions, omissions, substitutions, and other modifications can be made thereto without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered to be limited by the foregoing description and is only limited by the scope of the appended claims.

## Claims

1. A coaxial connector configured on an end of a coaxial cable including a central conductor, a dielectric surrounding the central conductor, an external conductor that covers the dielectric, and an insulating sheath that clads the external conductor, the coaxial connector comprising:
a contact capable of being connected to a cylindrical mating contact, the contact including a pair of fixed terminals and a movable terminal, the terminals being erected from a tip end side of a strip-shaped metal plate and being capable of externally contacting the mating contact by three-point contact;
a housing including a first connection base and a second connection base, the first connection base including an accommodation space in which one surface side is open such that the mating contact is insertable and the pair of fixed terminals and the movable terminal are disposed inside, the second connection base partially protruding from the first connection base;
a conductive shell including a cylindrical portion that is open to the one surface side and is provided to surround the first connection base, and an extension portion at least including a gutter-shaped portion that is coupled to the cylindrical portion and is capable of accommodating the second connection base therein; and
a crimp housing including a slot that is notched so as to be capable of pressing an outer periphery of the central conductor and capable of being inserted from an opening side of the accommodation space toward a predetermined portion of the second connection base,
wherein the contact includes an installation surface in which a base end side of the metal plate is exposed on a predetermined surface of the second connection base, the installation surface being capable of coming into contact with the central conductor, and
wherein the extension portion of the shell includes a pair of first barrels capable of pressing the crimp housing against the second connection base, and a pair of second barrels capable of crimping the external conductor.

2. The coaxial connector according to claim 1, wherein the crimp housing includes a pair of lances, and
the second connection base portion is formed a pair of steps that can be engaged with the pair of the lances at a predetermined portion thereof.

3. The coaxial connector according to claim 1, wherein
the pair of fixed terminals are located at a set of vertices among vertices of a virtual equilateral triangle inscribed in the mating contact, and
the movable terminal is located at the other vertex of the virtual equilateral triangle, and is disposed in a state of facing an intermediate portion of the pair of fixed terminals.

4. The coaxial connector according to claim 1, wherein
the contact is molded integrally with the housing, and the contact includes at least:
an installation surface in which a base end of the metal plate is exposed on a predetermined surface of the second connection base, the installation surface being capable of coming into contact with the central conductor; and
contact edges of the pair of fixed terminals, the contact edges being exposed to the accommodation space and capable of coming into contact with the mating contact.