EP1366546B1

EP1366546B1 - Coaxial connector

Info

Publication number: EP1366546B1
Application number: EP02702361A
Authority: EP
Inventors: Frank Hellin; Reginald Leeman
Original assignee: Tyco Electronics Belgium EC BVBA
Current assignee: TE Connectivity Belgium BV
Priority date: 2001-02-28
Filing date: 2002-02-21
Publication date: 2011-01-19
Anticipated expiration: 2022-02-21
Also published as: DE60238971D1; WO2002069457A8; ATE496409T1; WO2002069457A1; EP1366546A1

Abstract

The present invention relates to a coaxial connector comprising a substantially tube-shaped housing serving as an outer conductor, a center conductor which is insertable into the housing and a dielectric part which is arranged between the housing and the center conductor as an insulating mechanical support to separate the center conductor from the outer conductor. In order to provide a coaxial connector that can be produced economically, allows an easy assembly and requires no additional fixing parts, according to the present invention, the dielectric part is shaped such that it is easily deformable with respect to its circumferential dimension. According to advantageous embodiments either its inner or its outer circumferential dimensions or both can be deformable.

Description

The present invention relates to a coaxial connector according to the preamble of claim 1.
Coaxial connectors of this kind can be used in a vast field of application to connect coaxial cables with each other or to a diversity of electronic components. Coaxial cabling is the primary type of cabling used by the cable television industry and is also widely used for computer networks. Although more expensive than standard telephone wire, it is much less susceptible to interference and can carry more data. Because the cable television industry has already connected millions of homes with coaxial cable, this network can also provide the basis of the so-called information highway. Coaxial connectors are also used in the framework of hybrid fiber coax (HFC) networks, broad band cable networks which are able to transmit video, voice and data signals between a head end and a subscriber. Single mode fiber cable is used to link the head end with the fiber node or optical network unit. The coaxial cable network connects the fiber node with the subscriber.
Another important field of application represents the telecommunication, where coaxial connectors are used for different connections in base stations of mobile communication network.
Generally, a coaxial connector comprises two concentric conductors which are separated by a dielectric and is most commonly used as an extension for a transmission line to facilitate interconnection. Basically, a coaxial connector consists of the following components:

a center contact which is affixed to the center conductor of the coaxial cable as an extension of the signal path,
a connector housing which is affixed to the braid or strength member of the cable as an extension of the ground path,
a connector insulator that serves as mechanical stabilization and as a dielectric between center contact and connector housing,
an outer jacket which is a protective cover against environmental effects.

In conventional coaxial connectors, the fixing of the dielectric in the housing, which represents the outer contact, is done by assembling an extra part, which is, for example, a ring-shaped part. As an alternative, the housing of a conventional coaxial connector consists of more than one part. The dielectric is mounted in the housing before the parts that form the housing are assembled. These conventional coaxial connectors have the disadvantage that either additional fixing parts are required for a mechanical stabilization of the dielectric part or that the housing has to be composed of several parts.
US 4,377,320 discloses a coaxial connector for terminating a coaxial transmission line. The connector includes a tubular spring element, comprising a cylindrical body having a plurality of reversely formed leaf spring fingers annularly spaced, and projecting forwardly therefrom. A dielectric body is inserted into the axial bore of the tubular spring element and their position serves to electrically insulate the spring element from a center contact when inserted into the bore of the dielectric body. Insertion of the contact into the dielectric body causes an outward deflection of an inner cylindrical portion of the dielectric body. Thus, the inner cylinder serves as a resilient spring and provides the requisite resilient retention forces for retaining the center contact within the dielectric body.
JP 07-22124 A relates to casing for an electronic apparatus where a cylindrical external conductor is formed on the wall surface. A hollow insulative material is provided for fixing a center conductor to the tube-shaped opening of the wall. According to this document, the dielectric part has short slits in order to provide resiliency of a front region to be fixed by a snap connection within the casing.
Therefore, the problem underlying the present invention is to provide a coaxial connector that is composed of less components and can be assembled in a more simple and economic way.
This problem is solved by a coaxial connector with the features of claim 1 and the corresponding assembly method according to claim 7. Advantageous embodiments of the invention are the subject matter of several dependent claims.
A particular advantage of the coaxial connector according to the present invention can be seen in the fact that neither extra parts are required for fixing the dielectric part in the housing, nor the housing has to be composed of several parts. Moreover, neither high mounting forces are required for assembling the dielectric part and the center conductor, nor the center conductor has to be composed of several parts. Consequently, the fabrication of the coaxial connector is cheaper and the assembly process is shorter and easier.
In order to provide an effective way to allow an elastic deformation of the ring-shaped dielectric part with respect to its outer circumferential dimension, the dielectric part can comprise, according to an advantageous embodiment, a ring-shaped outer sleeve having at least one incision.
According to another advantageous embodiment, the dielectric part comprises a ring-shaped inner sleeve which is connected to the outer sleeve by at least one bridging element and has at least one incision. This embodiment offers the advantage of an easy and economical mounting of the center conductor.
When the outer diameter of the undeformed dielectric part is larger than the inner diameter of the housing, the dielectric part can be fixed in its final position after removing the applied mechanical or thermal stress.
In providing a recess in the housing, wherein the dielectric part fits after assembly of the connector, a secure fit of the dielectric part can be provided.
In order to provide an effective way to allow the elastic deformation of the ring-shaped dielectric part with respect to its inner circumferential dimension, the dielectric part can comprise, according to an advantageous embodiment, a ring-shaped inner sleeve having at least one incision.
When constructing the dielectric part with a ring-shaped outer sleeve being connected to the inner sleeve by at least one bridge element, a stable and secure mechanical contact between the dielectric part and the housing can be achieved.
According to another advantageous embodiment, this outer sleeve has at least one incision. This embodiment offers the advantage of an easy and economical mounting of the dielectric part in the housing.
When the inner diameter of the dielectric part is smaller than the outer diameter of the center conductor, the dielectric part can be fixed in a recess in the center conductor, wherein the dielectric part fits after assembly of the connector to provide a secure fit of the dielectric part.
According to an alternative advantageous embodiment, the dielectric part comprises a ring-shaped outer sleeve having along its circumference, a plurality of resilient protrusions essentially directed towards the center conductor. This embodiment offers the advantage that the mounting forces required insertion of the center conductor are particularly low.
When the dielectric part snaps into an annular recess provided at the outer surface of the center conductor, a particularly secure fit of the dielectric part and the center conductor can be achieved.
An assembly method according to the present invention shows the advantage that by inserting the ring-shaped dielectric part in a deformed condition, the same is fixed in the housing by the mere removal of the applied mechanical or thermal stress. No further assembly steps, such as mounting further parts, are required.
The use of a tube-shaped first mounting aid with a conical inner surface represents an effective way of applying mechanical stress in order to deform the dielectric part.
This first mounting aid can also be an integral part of the housing, thereby reducing the amount of additionally required parts.
A very easy way of moving the dielectric part inside the housing is the use of a piston-shaped second mounting aid.
When the dielectric part snaps into an annular recess provided at the inner surface of the housing, a secure fit of the dielectric part can be achieved.
The advantageous embodiments of the invention will be further understood from the following description, with reference to the drawings in which:

Fig. 1: shows a partly cross-sectional view of an advantageous embodiment of the co- axial connector according to the present invention;
Fig. 2: shows a side view of a partly stripped coaxial cable;
Fig. 3: shows a perspective view of the coaxial connector according of Figure 1;
Fig. 4: shows a side view of a dielectric part according to a first embodiment;
Fig. 5: shows a perspective view of the dielectric part according of Figure 4;
Fig. 6: shows the mounting sequence for the assembly of the dielectric part in the housing;
Fig. 7: shows a sectional view of the housing and the dielectric part mounted therein;
Fig. 8: shows a side view of the dielectric part according to the first embodiment with the center conductor mounted therein;
Fig. 9: shows a sectional view of the dielectric part according to Figure 8 along the cut- ting line A - A;
Fig. 10: shows a side view of the dielectric part according to a second embodiment;
Fig. 11: shows a side view of the dielectric part according to a third embodiment;
Fig. 12: shows a side view of the dielectric part according to a fourth embodiment;
Fig. 13: shows a side view of the dielectric part according to a fifth embodiment;
Fig. 14: shows a side view of the dielectric part according to a sixth embodiment;
Fig. 15: shows a side view of the dielectric part according to a seventh embodiment;
Fig. 16: shows a side view of the dielectric part according to a eighth embodiment;
Fig. 17: shows a side view of the dielectric part according to a ninth embodiment;
Fig. 18: shows a perspective view of the dielectric part according to a tenth embodiment;
Fig. 19: shows a side view of the dielectric part according to Figure 18;
Fig. 20: shows a sectional view of the dielectric part according to Figure 19 along the cutting line B - B.

Figure 1 shows a partly sectional view of a coaxial connector according to the present invention. According to an advantageous embodiment, the shown connector is designed for the use with a coaxial cable. The coaxial connector 100 comprises a housing 104 which serves as an outer connector. The pin-shaped center conductor 108 which contacts the center conductor 124 of the cable (see Figure 2), can be inserted into the housing 104 and is mechanically stabilized as well as electrically insulated against housing 104 by a ring-shaped dielectric part 102. The coaxial cable 110 can be inserted into the housing 104 from that side, which is opposite to the center conductor 108. The cable 110 is secured to the connector 100 by means of a clamp ring 112 which engages with a clamp nut 114. A cable gasket 116, which is preferably fabricated out of silicon rubber, is in direct contact with the cable jacket 128 (see Figure 2). The clamp ring 112 connects the outer conductor of the cable 126 electrically to the housing 104. A coupling nut 122 secures the coaxial connector 100 to its counterpart which is not shown in the figure. A C-ring 120 fixes the nut to the connector 100. Further gaskets 118 and 119 tighten the contact against environmental effects.
Figure 2 shows the cable strip dimensions of the coaxial cable 110. Figure 3 is a perspective view of the coaxial connector.
As the dielectric part 102 is elastically deformable with respect to its outer circumferential dimension, it can be inserted into the housing 104 and fixed in an annular recess of the housing without requiring any further parts and without providing a multi-part structure of the housing. Moreover, the dielectric part 102 can be elastically deformable with respect to its inner circumferential dimension, thus enabling the center conductor 108 to be fabricated out of one single part and to be inserted with low mounting forces.
Figures 4 and 5 show an advantageous embodiment of the dielectric part 102. The dielectric part is composed of an inner and an outer sleeve 138 and 140 which are connected to each other by bridge elements 142. The inner sleeve as well as the outer sleeve have incisions 144, which enable an elastic deformation of the dielectric part 102 when a radially directed mechanical stress is applied onto the outer surface of the outer sleeve 140. Under mechanical stress, the outer circumferential dimension of the outer sleeve 140 is therefore reduced, which allows an easy insertion of the dielectric part 102 into the housing 104. After releasing the mechanical stress, the dielectric part 102 regains its original shape and can therefore be fixed securely in the recess 136 of the housing 104.
The dielectric part 102 can also be deformed by thermally shrinking the same during the assembly procedure.
Figure 6 shows the mounting sequence of the assembly of the dielectric part 102 into the housing 104. For a better understanding, all parts are shown in a sectional view.
Step S1 shows all required components before assembly: the housing 104, a first mounting aid 130, the dielectric part 102 and a second mounting aid 132. The first mounting aid is substantially tube-shaped and has a region 131 with a conical inner surface. The first mounting aid 130 has an insertion funnel 133, which can be inserted into the housing 104. The region with a conical inner surface 131 has its smallest diameter adjacent to the insertion funnel 133.
In step S2 the first mounting aid 130 is inserted into the housing 104. The insertion funnel 133 fits into a reception opening 135 of the housing 104. The dielectric part 102 is partly inserted into the opening 134.
In step S3 the piston-shaped second mounting aid 132 is inserted into the opening 134 and moves the dielectric part 102 in the direction to the housing 104.
The dielectric part 102 has entered the region with the conical inner surface 131 in step S4. By moving forward towards the housing 104, the dielectric part 102 now is elastically deformed with respect to its outer circumferential dimension.
Finally, in step S5 the dielectric part is pressed by the piston-shaped second mounting aid 132 out of the first mounting aid 130 into the housing. When leaving the insertion funnel 133 of the first mounting aid 130, the mechanical stress applied to dielectric part 102 is released and the dielectric part 102 snaps into an annular recess 136 of the housing 104. After this mounting sequence, the two mounting aids 130 and 132 can be removed and the dielectric part 102 and the housing 104 are assembled as shown in a sectional view in figure 7.
The first mounting aid 130 can also form an integral part of the housing 104.
As can be seen from Figures 4 and 5, when the inner conductor is inserted into the dielectric part 102, the inner sleeve opens, thereby enlarging the inner diameter of the dielectric part 102. The inner conductor 108 now can be moved to its final position with respect to the dielectric part 102, where a recess 148 is provided (see Figures 8 and 9). After having reached the final position, the dielectric part snaps into the recess 148 and is securely fixed to the inner conductor 108.
Figures 10 to 17 show further advantageous embodiments of the dielectric part 102.
Figure 10 shows an embodiment of the dielectric part, where four bridge elements 142 are provided. The inner sleeve has an incision 144 in order to allow an easy insertion of the inner conductor by an elastic deformation of the dielectric part 102. However, this embodiment can also be realized without this incision, as shown in figure 11. Figure 12 also shows an embodiment of the dielectric part 102 having four bridge elements 142. The outer sleeve 140 is reduced to protruding elements 146 being in contact with the housing 104. Thus, the required material for the dielectric part can be reduced significantly. In the inner sleeve 138, an incision 144 is provided for the insertion of the inner conductor 108.
As can be seen in figure 13, the bridge elements 142 can be provided with supporting elements 146, which are in contact with the housing 104. The supporting elements 146 have a straight form and contact the housing with their slanted regions 148. The inner sleeve 138 can have an incision 144 as shown in Figure 14.
According to another advantageous embodiment, which is shown in figure 15, the bridge elements 142 serve as the mechanical support between the center conductor 108 and the housing 104 and are in direct contact with the housing 104. No outer sleeve or further supporting elements are provided.
As shown in figure 16, the outer sleeve 140 can also be realized without any incisions. Such an embodiment of the dielectric part 102 can be chosen when the size reduction of the dielectric part is done by thermal shrinking.
According to another advantageous embodiment, several regions 150 of the inner sleeves 138 and of the supporting elements 146 are thinned in order to allow an easy deformation of the dielectric part 102 when mechanical stress is exerted on same (see figure 17).
Figures 18 to 20 show the dielectric part 102 according to another advantageous embodiment. As can be seen for instance from the view shown in Figure 18, the dielectric part 102 comprises a ring-shaped outer sleeve 140 having along its inner circumference a plurality of resilient protrusions 146, which are essentially directed towards the center conductor 108. When the center conductor 108 is inserted into the dielectric part 102, the resilient protrusions 146 are elastically deformed and the center conductor 108 can be mounted without significant mounting force. In the final position of the dielectric part, the resilient protrusions 146 can snap into a correspondingly formed recess 148 (see Figures 8 and 9) of the center conductor 108. Thus, the center conductor and the dielectric part 102 are secured to each other. As can be seen in Figure 20, half of the resilient protrusions are directed with an angle of approximately 45° with the axial direction of the center conductor 108 towards the free end of the center conductor, whereas the other half is inclined towards the opposite end. Therefore, a secure fit of the dielectric part 102 can be achieved for all directions of axial mechanical forces.

Claims

Coaxial connector comprising a substantially tube-shaped housing (104) serving as an outer conductor, a center conductor (108) which can be inserted into the housing (104) and a dielectric part (102) which is arranged between the housing (104) and the center conductor (108) as an insulating mechanical support to separate the center conductor (108) from the outer conductor, the dielectric part (102) having an inner sleeve (138) and an outer sleeve (140) being connected by at least one bridge element (142),
characterized in
that at least one of the inner sleeve (138) and the outer sleeve (140) has at least one continuous incision (144) to provide resiliency.
Coaxial connector according to claim 1, characterizes In that the outer sleeve (140) is ring-shaped.
Coaxial connector according to claim 1 or 2, characterized in that the inner sleeve (138) is ring-shaped.
Coaxial connector according to one of the claims 1 to 3, characterized In that the outer diameter of the undeformed dielectric part (102) is larger than the inner diameter of the housing (104).
Coaxial connector according to one of the claims 1 to 4, characterized in that the housing (104) has an annular recess (136) wherein the dielectric part (102) fits after assembly of the connector (100).
Coaxial connector according to one of the claims 1 to 5, characterized In that the
inner diameter of the dielectric part (102) is smaller than the outer diameter of the center conductor (108).
Method for the assembly of a coaxial connector comprising a coaxial connector according to claim 1, comprising the following steps:
reducing the outer circumferential dimension of the dielectric part by inserting the dielectric part into the housing through a conical inner surface of a tube-shaped first mounting aid;

inserting the deformed dielectric part into the housing until the same has reached a final position;

removing the stress in order to fix the dielectric part in the final position.
Method according to claim 7, characterized in that said first mounting aid forms an integral part of the housing.
Method according to claim 7 or 8, characterized in that the dielectric part is inserted into the housing by means of a piston-shaped second mounting aid.
Method according to one of the claims 7 to 9, characterized in that after removal of the stress the dielectric part fits into an annular recess provided at the inner surface of the housing.