Electrical connector provided with a cable clamping device

The invention relates to a cable clamping device, for example for an electrical connector, comprising at least one bushing and a clamping ring. The bushing and the clamping ring both comprise an opening for the passage of a cable. A bushing has a number of bushing portions which, joined together, form a sleeve about the cable. Two flanges bear the bushing portions and are articulated to a casing so as to pivot between an unclamped position of each bushing, in which the cable can be moved, and a clamped position, in which each bushing is kept clamped to the cable by the clamping ring. Locking means keep the clamping ring in the position in which the cable is clamped by the bushing.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a national stage application under 35 U.S.C. §371 of PCT Application Number PCT/EP2014/077555 having an international filing date of Dec. 12, 2014, which designated the United States, said PCT application claiming the benefit of priority under Article 8 of the Patent Cooperation Treaty to French Patent Application No. 1362486, having a filing date of Dec. 12, 2013, the entire disclosure of each of which are hereby incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The invention relates to the field of electrical connectivity, for example electrical power connectors and, in particular, electrical power connectors for hybrid motor vehicles.

BACKGROUND OF THE INVENTION

Electrical power connectors are used in electric or hybrid motor vehicles, for example in order to connect a set of batteries to an electric motor, to a power converter, etc.

In hybrid vehicles the heat engine generates vibrations that are transmitted to the power cables and therefore also to the connectors and contacts thereof. Because the section of the power cables is relatively large (for example 40 or 50 mm2), said cables are rigid and have a significant inertia. The level of these vibrations can reach 15 G, 25 G or 40 G depending on where the cables and the connectors are located. With such levels of vibration, the points of electrical contact between the electrical contacts of the connectors can become worn prematurely. This results in a risk of heating and even fire. It is therefore important to prevent this risk.

BRIEF SUMMARY OF THE INVENTION

A cable fixing and clamping device is proposed, in particular for an electrical connector, comprising a bushing, a clamping ring and locking means carried at least in part by the clamping ring, making it possible to block the displacement of the clamping ring relative to the bushing. In this document a bushing constitutes fundamentally a hollow sleeve having an essentially cylindrical inner wall ensuring the clamping and the blocking of one or more cables and an outer wall, which likewise is essentially cylindrical and on which a clamping ring is placed. The bushing can be formed of one or more parts (for example two half-bushings). One and/or the other of these parts have/has an inner surface corresponding to at least one substantially cylindrical portion (a half-cylinder for a half-bushing, for example). The bushing can be located for example on a connector or on any other device comprising one or more contacts to be protected from vibrations or upstream thereof.

Numerous forms and configurations of bushings or bushing portions as well as a varying number of bushings can be envisioned. For example, there may be provided two complementary half-bushings forming a substantially cylindrical passage with a closed or almost closed circular circumference when said half-bushings are clamped on the cable. A fixed bushing portion and a bushing portion movable about an axis of rotation to which said bushing portion is articulated can be provided. It is also possible to have two half-bushings movable about the axis of rotation to which said half-bushings are articulated, respectively. It is also possible to have a number of pairs of half-bushings, each pair blocking a cable, respectively.

The bushing and the clamping ring both comprise an opening (i.e. a passage) for passing through a cable. The bushing and the clamping ring are both parts made of plastics material, for example. At least one of the elements from the bushing and the clamping ring has an inner surface intended to press against an outer surface of the cable or an element connected thereto, such as a portion of thermo-shrinking sheath. This inner surface thus comes into contact with the cable in order to block the cable when the clamping ring is displaced, relative to the bushing, from a position in which the clamping ring is disengaged from the bushing and a displacement of the cable is possible, into a position in which the cable is blocked. This inner surface can be located for example on a movable bushing portion (half-bushing for example) carried by a plate (in other words in this context a skirt) articulated about an axis of rotation. If the same plate carries one or more bushing portions, each movable bushing portion is then articulated to a flange about an axis of rotation between an unclamped position, in which the cable can be displaced, and a clamped position, in which the bushing portions are held clamped on the cable by the clamping ring when said ring is manipulated in order to clamp the cable in the clamping device. A movable bushing portion is not only articulated to a flange, but can also be mounted on this flange so as to be removable. It is thus made possible to assemble bulky contacts and a unitary wire seal before the assembly of the bushing portions and respective plates thereof. Each movable bushing portion thus contributes to the blocking of the contact and of the seal, respectively, in a cavity and a recess provided for this purpose.

When the movable bushing is in a position clamped on the cable, the inner surface is distanced from the axis of rotation by a radius greater than the shortest distance between the axis of rotation and the outer surface of the cable. In other words, when the movable bushing portion is in a position clamped by the clamping ring, the inner diameter of the passage of the cable at the bushing is smaller than the outer diameter of the cable and the outer insulating sheath thereof. This is produced thanks to a tilting effect of the bushing portion (or portions) movable about the axis of rotation, which makes it possible to release or partially block the passage of the cable.

It is important to bear in mind that the clamping device according to the invention comprises only few elements and that the clamping ring is the element that is directly manipulated by an operator in order to be displaced, relative to the bushing, from a position in which the cable is not clamped and can still be displaced through the passage formed in the clamping ring and the bushing, into a position in which the cable is blocked and can no longer be displaced easily through the passage.

The locking means are carried at least in part by the clamping ring so as to be activated during the clamping of the clamping ring. The locking means have at least one non-return catch. A non-return catch of this type makes it possible to block the displacement of the clamping ring relative to the bushing in a path or direction opposite the displacement of the clamping ring relative to the bushing. Such locking means also make it possible to prevent the ring from unclamping, even when the fixing device is subjected to strong vibrations, moreover for long periods of time (which would not necessarily be the case with a screw-type device).

The clamping ring is displaced relative to the bushing in a first step by translation in order to clamp the bushing on the cable, then in a second step by rotation in order to lock the clamping ring on the bushing. This has improved ergonomics compared with a rotation of the ring on a thread of the bushing. In fact, in the case of a thread, a number of revolutions of the ring would be necessary in order to obtain the translation sufficient for the displacement of the bushing on the cable. A screwing of this type of the ring on the bushing can prove to be tedious and can be made difficult when the fixing device is located in a cluttered or confined environment.

Thus, in order to provide a displacement of the ring on the bushing in translation parallel to the longitudinal axis of the cable, it is possible to press on the clamping ring parallel to this axis. This can be implemented relatively easily even when the circular surroundings around the clamping ring are cluttered. Likewise, to clamp the ring on the bushing by rotation, it is possible to rotate the clamping ring over less than one revolution. This makes it possible to provide cable clamping devices that are particularly ergonomic.

DETAILED DESCRIPTION OF THE INVENTION

The cable clamping device1shown inFIGS. 1, 2A to 2G, 3A to 3D, 4A and 4Bis a device for an electrical contact casing5intended to be mounted on the body of an electrical power device, such as a converter. At the same time as the mounting of the casing5on the power device, the contacts19(male contacts here) are connected to female contacts mounted for example on an electrical circuit that has bus bars.

In the illustrated example the clamping device comprises a casing5, inside which there are formed three cavities40(see alsoFIGS. 3A to 3D). The casing5is surrounded at least in part by a metal shield plate41suitable for providing a shielding continuity between a braid (not shown) surrounding the cables4and the body of an electrical power device (also not shown). The braid is held on the metal shield plate41by means of a collar (not shown). The casing5and the metal shield plate41can be mounted in a screwed manner on the body of the electrical power device.

As illustrated inFIG. 2A, each cavity40accommodates a contact19and a unitary wire seal12. Before clamping of each contact19on a cable4, a clamping ring3and a seal12are threaded onto said cable4. Each contact19is then positioned in a cavity40, then each seal12is pushed into a recess42located at the rear of each cavity40(seeFIG. 2B). Each cavity40is also extended at the rear by two flange portions43. Each flange portion43extends circularly around each cable4over substantially a quarter of a circle. Each flange portion43comprises an opening44.

As illustrated inFIGS. 2C and 2D, a lower plate45, combining three half-bushings50in a single piece, is placed at the rear of the three cavities40. This lower plate45is placed beneath the cables4and is held on the three lower flange portions43at least in part by means of three lugs46each inserted, respectively, into an opening44(see alsoFIG. 3A). Similarly, an upper plate47, similar to the lower plate45, is placed symmetrically above the cables4with respect to the lower plate45and is held on the three upper flange portions43at least in part by means of three lugs46each inserted, respectively, into an opening44(FIGS. 2D and 3A). The lower45and upper47plates are therefore articulated around points of rotation R located substantially at the lugs46inserted into the openings44. In other words, the lower45and upper47plates are each articulated, respectively, about an axis of rotation passing through three of these points of rotation R, said axes of rotation being symmetrical to one another with respect to a plane passing substantially through the longitudinal axes of the cables4.

Once in place, each pair of half-bushings50opens like a jaw. In this position of the half-bushings50, the cables4are not yet blocked and can be displaced through the passage formed between said half-shells (seeFIGS. 2D and 3A).

Each element formed of a plate45,47and three half-bushings50carried thereby is L-shaped in section perpendicular (plane ofFIGS. 3A to 3D) to its axis of rotation and passing through the points of rotation R. One of the branches of this L corresponds to a half-bushing50and the other of these branches corresponds to a plate45or47connecting the three half-bushings50to one another. The lugs46are located at the tip of the free end of the branch of the plate45,47(see in particularFIGS. 3A to 3D).

When the half-bushings50are joined to one another, the respective plates45,47are aligned (FIGS. 2E to 2G, 3C and 3G). One of the advantages of having a sole element formed of a plate45,47and a number of bushing portions (here three half-bushings50), said element being common to a number of cables4(and possibly identical on either side of the cables4), lies in the fact that this reduces the number of parts to be produced, handled and assembled.

Each bushing portion (here a half-bushing50) comprises an inner surface34corresponding to a cylinder portion (here substantially hemicylindrical). Bringing the bushing portions toward one another makes it possible to form a complete bushing2in the form of a hollow sleeve, one around each cable4, with an essentially cylindrical inner wall52assuring the clamping of a cable4and with an outer wall54, which likewise is essentially cylindrical and on which a clamping ring3is placed. In accordance with variants the bushing portions could correspond to portions smaller than a cylinder and longitudinal slots could be formed, in the complete bushing, between the bushing portions. In other words the bushing portions are not necessarily joined in the complete bushing. The bushing2and the clamping ring3each comprise an opening26,27for passing through a cable4. Each clamping ring3can then be inserted on a bushing (seeFIGS. 2E, 2F, 3B and 3C).

Each clamping ring3and each half-bushing50has beveled surfaces57, sliding over one another so as to facilitate the insertion of each clamping ring3on a bushing2. When a clamping ring3is moved in translation longitudinally along a bushing2, toward a seal12, said clamping ring is displaced, relative to the bushing2, from a position in which the cable4can be displaced into a position in which the cable4is blocked. At the same time, the half-bushings50and the plates45,47pivot about the axis of rotation in order to bring said plates toward one another.

When a clamping ring3is abutted against the lower45and upper47plates, the bushing2on which said clamping ring is mounted is completely locked on the cable4, and said cable is blocked (seeFIGS. 2F and 3C).

As shown schematically inFIG. 5, so that the cable4can be blocked during the rotation of the lower45and upper47plates about the axis of rotation thereof, it is necessary for a least a portion of the inner surface34to be distanced from the axis of rotation by a radius r greater than the distance d between the axis of rotation and the outer surface58of the cable4. In order to increase the efficacy of the blocking, the inner surface of the sleeves comprises ribs59, of which the inner diameter, once the lower45and upper47plates have been brought toward one another, is smaller than the outer diameter of the insulating sheath of the cable4.

In order to ensure that each clamping ring3will not escape from the bushing2on which it is mounted, each clamping ring3is held on a bushing2non-rotatably by locking means. These locking means comprise ramps21on each bushing2and on each clamping ring3(seeFIGS. 4A and 4B) and are arranged in a circular manner about the longitudinal axis L of the cables4.

By rotating a clamping ring3with respect to a bushing2by substantially less than a quarter of a turn (see visual displacement references60between their unlocked position inFIG. 2Fand their locked position inFIGS. 1 and 2G), said clamping ring is locked on said bushing2.

As can be seen inFIG. 4A, the clamping ring3is held in an unlocked (or pre-locked) position thanks to a tooth30, which cooperates with an indentation29preceding a series of teeth31located on a ramp21and protruding on the inner surface of the clamping ring3. As shown inFIGS. 3C and 3D, each bushing2comprises a circular recess portion61suitable for receiving a pin62protruding on the inner surface of the clamping ring. In an unlocked position of the clamping ring3, the pin62is not engaged with this circular recess portion61, and the clamping ring3can therefore be removed from the bushing2.

InFIGS. 3D and 4B, after rotation through approximately a quarter of a turn of the clamping ring3, the clamping ring3is held in a locked position. The pin62is now engaged with the circular recess portion61, and the clamping ring3therefore can no longer be removed from the bushing2. The tooth30has slid over the set of teeth31, so as to become housed in a notch63. The teeth30,31constitute locking means with non-return catches. The visual displacement reference60is now located opposite an opening44.

FIG. 5shows another embodiment of the invention. This is an electrical connector. It comprises a casing5and two contacts, each clamped on a cable4. A clamping device1as described above, but having two bushings2and2clamping rings3(instead of three) is formed integrally (for example by molding) with the casing5in order to limit the propagation of vibrations from the cable4to the contacts.