Connector

A connector includes a back housing, a front shell having a barrel portion and a grounding portion continuous with a rear portion of the barrel portion, and a cover shell. The cover shell has a contacting portion contacting a rear end upper portion of the front shell, a catching portion catching on the grounding portion, and a spring portion elastically deformed by catching of the catching portion. The elastic deformation of the spring portion causes the cover shell to contact the back housing while pressing the back housing frontward, and to contact the front shell while pressing the rear end upper portion of the front shell upward at the contacting portion.

FIELD OF THE INVENTION

The present invention relates to a connector suitable for transmission of a high frequency signal.

BACKGROUND

A high frequency signal is susceptible to electromagnetic noise, and, in order to reduce the influence of electromagnetic noise, a connector having a structure covered with a shield is adopted. That is, a connector is employed that has a structure where a contact for directly transmitting a high frequency signal is supported by a housing, and the contact and the housing are enclosed with a shield. For example, Japanese Patent Application No. 2016-018589A discloses a connector having a structure where a contact is supported by a housing referred to as an insulator, which in turn is enclosed with shields referred to as an outer peripheral shell and a back shell.

Each of the components constituting the connector has a tolerance, namely a dimensional tolerance. Therefore, this dimensional tolerance may cause the transmission characteristics of the connector completed by assembling such components together to vary among the connectors. If this variation is great, the connector must be handled as having low transmission characteristics according to the great variation, and thus the variation hinders configuring a connector having high-performance transmission characteristics. In order to reduce the dimensional tolerance, each component has to be manufactured with high precision, but pursuing this causes the components to be costly, and is therefore limited.

SUMMARY

A connector includes a back housing, a front shell having a barrel portion and a grounding portion continuous with a rear portion of the barrel portion, and a cover shell. The cover shell has a contacting portion contacting a rear end upper portion of the front shell, a catching portion catching on the grounding portion, and a spring portion elastically deformed by catching of the catching portion. The elastic deformation of the spring portion causes the cover shell to contact the back housing while pressing the back housing frontward, and to contact the front shell while pressing the rear end upper portion of the front shell upward at the contacting portion.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

A connector100according to an embodiment, as shown inFIG.3, is composed of a front shell10, a front housing20, a contact30, a back housing40, and a cover shell50.

The contact30is a component made of a conductor, for example, a copper alloy. The conductor constituting this contact30is equivalent to an example of a first conductor as referred to in the present invention. This contact30has a base portion31, a contact portion32, and a board connecting portion33.

The contact portion32extends from the base portion31in a frontward direction in which the connector100mates with a mating connector, and makes electrical contact with a mating contact provided in the mating connector. The contact portion32of the contact30of the present embodiment is a rod-like horizontally extending male contact portion.

As shown inFIG.3, the board connecting portion33extends from the base portion31in a downward direction in which a circuit board is positioned, and makes connection to the circuit board. Here, the board connecting portion33of the contact30of the present embodiment is of a surface mounting type that is soldered to the surface of the circuit board. That is, this board connecting portion33extends downward, and thereafter bends rearward and extends horizontally. This horizontally extending portion is placed on the surface of the circuit board and soldered thereto.

In an embodiment, the front housing20is composed of a resin that is an example of a first dielectric as referred to in the present invention. A longitudinal through-hole21is formed in the front housing20of the present embodiment, as shown inFIG.3. The front housing20supports the base portion31with the contact portion32of the contact30inserted through the hole21and exposed frontward.

In an embodiment, the back housing40is composed of a resin that is an example of a second dielectric as referred to in the present invention. This back housing40supports the base portion31such that the base portion31is held between the back housing40and the front housing20, with the board connecting portion33exposed downward.

In an embodiment, the front shell10is composed of a sheet material made of a conductor such as a copper alloy, and is stamped and formed. A conductor such as a copper alloy constituting this front shell10is equivalent to an example of a second conductor as referred to in the present invention. This front shell10has a barrel portion11and a grounding portion12.

The barrel portion11has a longitudinally extending substantially cylindrical shape. The contact portion32of the contact30is inserted into this barrel portion11, and the barrel portion11encloses the contact portion32inserted thereinto at a distance from the contact portion32.

The grounding portion12is continuous with a rear portion of the barrel portion11and widens downward. This grounding portion12makes connection to the circuit board. This grounding portion12, like the board connecting portion33of the contact, also bends rearward halfway and extends horizontally. This horizontally extending portion is placed on the surface of the circuit board and soldered thereto. The grounding portion12of the present embodiment has such a shape as to be soldered at two right and left locations.

The cover shell50, like the front shell10, is also composed of a sheet material made of a conductor such as a copper alloy, and is stamped and formed into such a shape as to cover the back housing40. The conductor, such as a copper alloy, constituting this cover shell50is equivalent to an example of a third conductor as referred to in the present invention. This cover shell50is formed with a contacting portion51, a catching portion52, and a spring portion53.

The contacting portion51contacts a rear end upper portion of the front shell10from below. Here, the rear end upper portion of the front shell10is provided with a rearward projecting tongue13. On the other hand, the contacting portion51is provided with a recess511for receiving the tongue13. The action of elastic deformation of the spring portion53, which will be described later, causes this cover shell50to press the tongue13received in the recess511upward, thereby ensuring reliable contact between the front shell10and the cover shell50.

In addition, the catching portion52catches on the grounding portion12of the front shell11. Specifically, the grounding portion12is provided with an extending portion121extending laterally. In addition, the catching portion52has a depression521(seeFIG.3andFIG.4A) depressed upward. This depression521of the catching portion52catches on the extending portion121such that it rests astride the extending portion121. The grounding portion12is provided with a pair of extending portions121extending rightward and leftward, respectively. Correspondingly, a pair of right and left catching portions52are formed, and the cover shell50catches on the front shell10at the two right and left catching portions52. These catching portions52catch on the extending portions121, thereby contacting the front shell10reliably. That is, the cover shell50contacts the front shell10at three locations in total: the contact portion51formed at the top; and the pair of right and left catching portions52at the bottom, and is kept at the same potential as the front shell10to serve as a shield.

When this connector100is assembled and the cover shell50catches on the extending portion121, the spring portion53elastically deforms. The elastic deformation of this spring portion53, on the one hand, as described above, causes the cover shell50to press the tongue13received in the recess511upward, thereby ensuring reliable contact between the front shell10and the cover shell50. In addition, on the other hand, the elastic deformation of the spring portion53causes the cover shell50to contact the back housing40while pressing the back housing40frontward. This prevents formation of a gap between the back housing40and the cover housing50regardless of a dimensional tolerance of a component such as the back housing40or the cover shell50, thereby reducing variations in the transmission characteristics among the connectors100.

In addition, the spring portion53has a shape projecting more frontward than the catching portion52. This spring portion53is also so formed as to be a pair of right and left spring portions. In the present embodiment, a hole531is formed in the spring portion53. Therefore, when the catching portion52catches on the extending portion121, the spring portion53undergoes elastic deformation accompanied by deformation of the hole531.

When this connector100is assembled, as shown inFIG.4A, the cover shell50is a component to be assembled last. When this cover shell50is assembled, the tongue13of the front shell10is received in the recess511of the contacting portion51, and the catching portion53is caught on the extending portion121. This causes elastic deformation of the spring portion53, and a force in the direction of a vector X shown inFIG.4Bis applied from the catching portion52of the cover shell50to the extending portion212of the front shell10. This vector X is decomposed into a horizontal component Y and a vertical component Z. The vertical component Z causes the tongue13of the front shell10to be pressed upward by the contacting portion51, thereby ensuring electrical contact between the tongue13and the contacting portion51, and simultaneously ensures that the catching portion52catches on the extending portion121, thereby also ensuring electrical connection between the catching portion52and the extending portion121. In addition, a reaction force of the horizontal component Y causes the back housing40to be pressed from behind by the cover shell50, thereby preventing creation of a gap between the back housing40and the cover shell50, as indicated by an arrow P inFIG.4C, regardless of a dimensional tolerance of a component.

A connector200according to another embodiment, also referred to as a comparative example, is shown inFIG.5.

The connector200of the comparative example shown inFIG.5is composed of a front shell10, a front housing20, a contact30, a back housing40, and a cover shell60. All of these components except for the cover shell60are the same as the corresponding components of the connector100of the present embodiment shown inFIG.3. On the other hand, the cover shell60is different from the cover shell50shown inFIG.3in that it lacks the spring portion53. In addition, this cover shell60of the comparative example has a structure where lanced tabs61are formed on right and left walls to hold the back housing40elastically therebetween from the right and left sides.

Regarding the connector100of the present embodiment and the connector200as the comparative example shown inFIG.5, variations in transmission characteristics due to a dimensional tolerance of a component will be discussed below.

FIGS.6A and6Bare side views of the connector200. Here,FIG.6Ashows the connector200with the cover shell60in contact with both the tongue13and the extending portion121of the front shell10. In addition, in the case of the connector200shown inFIG.6B, because the cover shell60is shorter in vertical dimension, or the like, a gap has occurred between the cover shell60and the extending portion121, as indicated by an arrow Q.

FIG.7is a diagram showing voltage standing wave ratio of the connector200. InFIG.7, the horizontal axis represents signal frequency (GHz), and the vertical axis represents voltage standing wave ratio (VSWR). In addition, the “contact” graph shown in the solid line is a graph when the cover shell60is in contact with both the tongue13and the extending portion121of the front shell10, as shown inFIG.6A. On the other hand, the “contactless” graph shown in the dashed line is a graph when the cover shell60is in contact with the tongue13of the front shell10but a gap lies between the cover shell60and the extending portion121, as shown inFIG.6B. The voltage standing wave ratio (VSWR) keeps its lower values until higher frequencies in the solid line graph.

FIG.8is a diagram showing impedance in the connector200. InFIG.8, the horizontal axis represents time (ps), and the vertical axis represents impedance (ohm). The respective meanings of the solid line and the dashed line are the same as inFIG.7. It can be seen that the impedance (ohm) is more stable at around 50 ohm in the solid line graph. In the case of the connector100of the present embodiment, regardless of variations among components, the cover shell50is always kept in contact with both the tongue13and the extending portion121of the front shell10.

FIGS.9A and9Bare partially cross-sectional side views of the connector200. Here, inFIG.9A, the cover shell60is in contact with the back housing40. On the other hand, in the case ofFIG.9B, because the cover shell60is longer in longitudinal dimension, or the like, a gap has occurred between the cover shell60and the back housing40, as indicated by an arrow R.

FIG.10is a diagram showing insertion loss in “Example” and “Comparative Example”. InFIG.10, the horizontal axis represents signal frequency (GHz), and the vertical axis represents insertion loss (dB). The “Example” refers to a connector100having the structure shown inFIG.3, and the “Comparative Example” refers to a connector200having the structure shown inFIG.5. In addition, “frontward”, “middle”, and “rearward” mean longitudinal positions of a rear face of the cover shell50(or the cover shell60) after assembly. In the case of the “Comparative Example”, when the cover shell60is more rearward, it means that a gap has occurred between the cover shell60and the back housing40, as shown inFIG.9B. The insertion loss (dB) is almost the same between the “Example” and the “Comparative Example”, and also between the “frontward”, the “middle”, and the “rearward”.

FIG.11is a diagram showing voltage standing wave ratio (VSWR) of “Example” and “Comparative Example”. InFIG.11, the horizontal axis represents signal frequency (GHz), and the vertical axis represents voltage standing wave ratio (VSWR). The respective meanings of “Example” and “Comparative Example” and of “frontward”, “middle”, and “rearward” are the same as inFIG.10. The “frontward”, the “middle”, and the “rearward” draw curves more approximate to each other in the “Example” shown in the solid line than in the “Comparative Example” shown in the dashed line inFIG.11.

FIG.12is a diagram showing impedance (ohm) of “Example” and “Comparative Example”. InFIG.12, the horizontal axis represents time (ps), and the vertical axis represents impedance (ohm). The respective meanings of “Example” and “Comparative Example” and of “frontward”, “middle”, and “rearward” are the same as inFIGS.10and11. As in the case ofFIG.11, the “frontward”, “middle”, and “rearward” draw curves more approximate to each other in the “Example” shown in the solid line than the “Comparative Example” shown in the dashed line.

As can be seen inFIGS.10to12, if there is the same dimensional tolerance, the connector100of the present embodiment can obtain more stable transmission characteristics than the connector200.

It should be noted that, though a connector provided with a male contact has been described here, the present invention is also applicable as it is to a connector provided with a female contact.

It should also be noted that, though a surface mounting type connector has been described here, the present invention is also applicable to a connector of a type that is inserted into a through-hole of a circuit board and soldered thereto.