CN107039786B

CN107039786B - Connection terminal for electrical equipment equipped with a clamping cage made of non-magnetic material

Info

Publication number: CN107039786B
Application number: CN201710013844.3A
Authority: CN
Inventors: 菲利普·方丹; 弗朗索瓦·法亚尔
Original assignee: TE Connectivity Services GmbH
Current assignee: Tyco Electronics Service GmbH; TE Connectivity Services GmbH
Priority date: 2016-01-08
Filing date: 2017-01-09
Publication date: 2021-06-04
Anticipated expiration: 2037-01-09
Also published as: EP3190664B1; EP3190664A1; CN107039786A; FR3046702A1; FR3046702B1

Abstract

A connection terminal (10) for an electrical apparatus, such as a junction box or a contactor, comprises a clamping element (12) formed of a non-magnetic material, the clamping element (12) being in the form of a cage capable of receiving an end of an electrical conductor (13) inserted in the clamping element (12). The connection terminal further comprises an actuating element (18) allowing the clamping element (12) to be changed between an undamped configuration, in which the end of the electrical conductor (13) can be freely inserted into the clamping element (12) or removed from the clamping element (12), and a clamped configuration, in which the end of the electrical conductor (13) previously inserted into the clamping element (12) is held in place by clamping between the clamping element (12) and the conductive strip (11) of the electrical apparatus, so as to establish an electrical contact between the conductive strip (11) and the end of the electrical conductor (13).

Description

Connection terminal for electrical equipment equipped with a clamping cage made of non-magnetic material

Technical Field

The present invention relates to a connection terminal for an electrical device such as a junction box or a contactor. The invention also relates to an electrical device itself.

Background

As is known, a connection terminal for mounting in an electrically insulating housing usually comprises a clamping element movably mounted in the insulating housing and an actuating mechanism for moving the clamping element.

The clamping element is intended to receive a free end of an electrical conductor inserted in a cavity defined by the clamping element, which is usually in the form of a cage. Due to the actuating mechanism, the clamping element can be varied between a position allowing the installation of the electrical conductor and a position in which the clamping element presses and holds the end of the electrical conductor against the conductive strip installed in the insulating housing.

In existing solutions, the clamping element is made by assembling together several parts, usually made of steel. Therefore, the assembly of the clamping element requires several operations, which is not optimal in terms of reducing costs and simplifying installation. There is also a risk that some parts are lost or degraded.

In addition, the use of steel is also problematic. In high power applications, for example in the case of electrical devices of the contactor or power terminal type, the electrical intensity circulating in the electrical conductors and strips may be greater than 100A. This may lead to high intensity eddy currents which are likely to cause heating of the parts made of steel and deformation of the clamping elements, which may lead to detrimental loosening of the conductive elements.

On the other hand, the thickness of the steel parts used to contain eddy currents must be limited below certain limits in order to avoid the following problems, which increases the necessity of using multiple-piece clamping elements that are assembled together.

Documents EP0687032a1 and FR2786611a1 describe solutions in which the clamping element is made at least partially of a non-magnetic material, but likewise in each case the clamping element is formed by a complex and expensive assembly of a plurality of parts assembled together, with the same risks in addition over time.

Disclosure of Invention

The present invention aims to solve all or part of the above-listed drawbacks.

In this situation, it is desirable to provide a simplified connection terminal for electrical equipment which is easy and less expensive to install, while at the same time improving its ability to operate in high power applications.

For this purpose, a connection terminal for an electrical apparatus, such as a junction box or a contactor, is proposed, comprising: a clamping element formed of a non-magnetic material, the clamping element being in the form of a cage capable of receiving an end of an electrical conductor inserted into the clamping element; and an actuating element which allows the clamping element to be changed between a release configuration (configuration) in which the ends of the electrical conductors can be freely inserted into or removed from the clamping element, and a clamping configuration in which the electrical conductors previously inserted into the clamping element are held in place by clamping between the clamping element and the conductive strip of the electrical device so as to establish electrical contact between the conductive strip and the ends of the electrical conductors, wherein the clamping element is constituted by a single one-piece integral piece.

Drawings

The invention will be best understood from the following description using specific embodiments thereof, given by way of non-limiting example and illustrated in the accompanying drawings, wherein:

fig. 1 is a perspective view of a portion of an example of an electrical apparatus equipped with two connection terminals, respectively in a clamped configuration and in an unclamped configuration and cooperating with the ends of two electrical conductors of different diameters, according to the invention.

Fig. 2 is a side view of the electrical apparatus of fig. 1 prior to installation of the electrical conductor shown in fig. 1.

Fig. 3 is a front view showing the same part of the electrical apparatus as fig. 1, but before the electrical conductors are mounted and showing the opposite configuration of the two connection terminals with respect to fig. 1.

Detailed Description

With reference to fig. 1 to 3, briefly given above, the present invention mainly relates to a connection terminal 10 for an electrical apparatus. Within said electrical apparatus, and as will be described in greater detail below, the connection terminal 10 has the function of establishing and maintaining a physical and electrical contact between the electrical conductor 13 inserted in the connection terminal 10 on the one hand and the conductive strip 11 of the electrical apparatus formed of conductive material on the other hand. In particular, the electrical device may be an electrical contact with an actuating element for establishing or interrupting electrical continuity or a junction box. The electrical apparatus may be configured to be detachably fixed to a fixing rail on which several electrical apparatuses, which may be the same or different from each other, may be mounted side by side.

The connection terminal 10 comprises a clamping element 12 formed of non-magnetic material which allows avoiding or limiting the formation of eddy currents mentioned in connection with the prior art previously proposed, even in particular for the purpose of high power applications involving the presence of an electrical strength greater than 100A circulating in the electrical conductor 13 and in the conductive strip 11.

The clamping element 12 is in the form of a cage capable of receiving an end of an electrical conductor 13 inserted into the clamping element 12. The term "cage" should be interpreted in a very broad sense, meaning an element defining an opening or a non-opening, with or without passing through a cavity, adapted to receive the ends of electrical conductors which may have different shapes, different dimensions, in particular different diameters or different lengths.

Each connection terminal 10 further comprises an actuation element 18 which allows the gripping element 12 of this connection terminal 10 to be changed between:

a release configuration, in which the end of the electrical conductor 13 can be freely inserted into the clamping element 12 or removed from the clamping element 12,

and a clamping arrangement, in which the end of the electrical conductor 13 previously inserted in the clamping element 12 is held in place by clamping between the clamping element 12 and the conductive strip 11, so as to establish electrical contact between the conductive strip 11 and the end of the electrical conductor 13.

In a very advantageous manner to solve the problems posed with respect to the prior art, the clamping element 12 is constituted by a single integral piece. This allows eliminating assembly and manufacturing problems, which further reduce costs and increase reliability while improving magnetic properties, to avoid as far as possible eddy currents in high power applications (in particular in the case of currents with a strength greater than 100A circulating in the electrical conductor 13 concerned and in the electrically conductive strip 11), which are particularly intended as fields of application of the invention.

By avoiding magnetic discontinuities or active or inactive contact breaks, the arrangement of the clamping element made of non-magnetic material and in the form of a single one-piece component actually provides better magnetic properties than a multi-piece assembly.

Typically, the non-magnetic material is configured such that the gripping element 12 has a spatially deformed state under the effect of heat generated by a magnetic field induced by an electrical strength greater than 100A circulating in the electrical conductor 13, such that the gripping element 12 prevents the end of the electrical conductor 13 from moving out of the gripping element 12 in the gripping configuration. Advantageously, therefore, when cycled with a strength greater than 100A, the single-piece clamping element (under the heating effect produced by this strength) has a deformation rate that ensures that the electrical conductor is kept below a given limit value of the axial removal force.

In other words, the non-magnetic material of the clamping element is adapted to enable the following functions, including: when such conditions are applied that the electrical strength in the electrical conductor is cycled more than 100A, a spatially deformed state is provided, ensuring that the clamping element prevents the electrical conductor from moving out of the element clamp. In practice, this adaptation of the non-magnetic material may depend on the shape of the clamping element, its thickness or on the maximum value of the removal force that the clamping element has to prevent. In particular, the adaptation of the non-magnetic material according to these characteristics can be carried out by numerical simulations and the person skilled in the art is fully capable of finding the non-magnetic material according to the dimensional or functional characteristics assigned to the clamping element.

In fact, providing a clamping element consisting of a single-piece integral piece allows this integral piece to undergo less deformation when it tends to heat under the effect of a cycle of electrical strength greater than 100A than a clamping element having the same overall dimensions but arranged in the form of a multi-piece assembly.

The structure of the clamping element in the form of a single piece part therefore not only allows for a more economical, more reliable, simpler and less risky loss or deterioration, but also a less deformable nature in order to improve the axial retention of the electrical conductor.

In particular, the non-magnetic material is a copper-based alloy, aluminum or an aluminum-based alloy, which gives very good results in practice.

Although the clamping element 12 shown here can be manufactured by any method and any process suitable for the desired purpose and result, the single-piece integral piece in which the clamping element 12 is constituted can advantageously be obtained by a simple pressing operation, which makes it very simple and inexpensive to manufacture and obtain.

According to a specific non-limiting embodiment, and as illustrated, the gripping element 12 is in the form of a profiled portion having a cross section with a closed profile. The cross section of each clamping element 12 may thus be in the form of a right circular or non-circular ring or loop, for example slightly oval, elongated in a direction substantially corresponding to the direction in which the clamping element 12 serves to ensure the clamping of the electrical conductor 13 and the conductive strip 11.

Such a closed shape of the cross-section allows the clamping element 12 to have very good magnetic properties, much larger than the cross-section of the open shape or a clamping element made of several pieces assembled together, allowing in particular a very low eddy current even when the electrical strength is greater than 100A in the electrical conductor 13 clamped by the clamping element 12 and in the electrically conductive strip 11.

When the clamping element 12 is obtained by extrusion, the cut section extends from the section considered perpendicular to the direction in which the clamping element 12 is extruded.

Very advantageously, the thickness of the clamping element 12 is at least locally between 2mm and 4 mm.

In addition to the use of non-magnetic materials and optionally features associated with the closed shape of the cross section of the clamping element 12, this dimensional feature allows to limit even more the heating and deformation effects of the clamping element 12 even when an electrical strength greater than 100A is circulated in the electrical conductor 13.

The electrical device includes an insulating housing 14 electrically formed from any suitable material, such as a plastic material, to simplify manufacture by injection. At least one connection terminal 10 is installed in the electrical apparatus, depending on the number of electrical conductors 13 to be connected. In the example shown, the electrical apparatus comprises two different connection terminals 10 independent of each other. The two connection terminals 10 allow electrical connection with the conductive strips 11 of two identical or different electrical conductors 13. In this case, each of the two connection terminals 10 is for receiving an end portion of a corresponding electrical conductor 13 (see fig. 1).

The insulating housing 14 may be one-piece or, as shown, be comprised of an assembly of several parts: in the example shown, the insulating housing 14 comprises two

portions

14a, 14b, these two

portions

14a, 14b being assembled together in a removable manner along a mounting direction which is generally perpendicular to the direction of insertion of the electrical conductors 13 into the two connection terminals 10. The fixing of the two

portions

14a, 14b can be achieved by snap-fitting, by means of screws or by any other equivalent means.

The insulating housing 14 includes: at least one receiving port 15 of a first type, in which receiving port 15 the end of the electrical conductor 13 tapers until it is inserted in the clamping element 12; and at least one receiving port 16 of a second type which allows insertion of another electrical conductor (not shown) different from electrical conductor 13 into insulating housing 14. Furthermore, the electrical apparatus comprises at least one bypass strip 17, which bypass strip 17 is configured to electrically link the electrically conductive strip 11 and the electrical conductor inserted in the receiving port 16 of the second type.

More precisely, in the non-limiting illustrated example, the insulating housing 14 comprises two receiving ports 15 according to the first type arranged on opposite lateral sides of the insulating housing 14. These two receiving ports 15 according to the first type allow receiving two electrical conductors 13, the two electrical conductors 13 being connected in two connection terminals 10 comprised in the electrical apparatus, the two connection terminals 10 being housed in an insulating housing 14.

Each receiving port 15 of the first type may comprise a protective seal (not shown) for sealing the receiving port 15 of the first type, prepared prior to installation by inserting an electrical conductor 13.

The insulating housing 14 further includes: two receiving ports 16 according to the second type, which receiving ports 16 are also arranged on the same two opposite lateral sides of the insulating housing 14, each receiving port 16 being located just above a receiving port 15 of the first type; and two bypass strips 17 different from each other and from the strip 11. The two receiving ports 16 according to the second type allow receiving two not shown electrical conductors, different from the detected electrical conductor 13, which are in contact with the bypass strip 17 to establish an electrical connection with the electrically conductive strip 11.

The connection terminal 10 and the conductive strip 11 and the bypass strip 17 are mounted in particular in one of the two

parts

14a, 14b of the insulating housing 14 before the two

parts

14a, 14b of the insulating housing 14 are assembled together. Fig. 2 shows the situation after assembling the two

parts

14a, 14b of the insulating housing 14 together before the electrical conductor 13 visible in fig. 1 is mounted.

Fig. 1 (in which the portion 14b of the insulating housing 14 is absent) shows the particular case in which the clamping element 12 of the left connection terminal 10 assumes its clamping configuration, while the clamping element 12 of the right connection terminal 10 is in its unclamped configuration. Still in fig. 1, the two electrical conductors 13 for linking to the conductive strips 11 by means of the two connection terminals 10 are different from each other: the diameter of the end of the right electrical conductor 13 that mates with the clamping element of the right connection terminal 10 in its undamped configuration is much larger than the diameter of the end of the left electrical conductor 13 that mates with the clamping element 12 of the left connection terminal 10 in its clamped configuration.

Each connection terminal 10 is configured such that, in the clamping configuration of the clamping element 12, the end of the electrical conductor 13 previously inserted into the clamping element 12 in its unclamped configuration is held in position by being clamped between the clamping element 12 and the electrically conductive strip 11 mounted in the insulating housing 14, so as to establish electrical contact between the electrically conductive strip 11 and the end of the electrical conductor 13.

It is therefore clear from the foregoing that the internal dimensions of the clamping element 12 for receiving the end of the electrical conductor 13 and the conductive band 11, as well as the structure of the actuating element 18, are configured to allow the cooperation with an end of an electrical conductor 13 having a diameter within a predetermined range of values.

However, in fig. 3, the portion 14b of the insulating housing 14 is still absent, the clamping element 12 of the left connection terminal 10 assuming its undamped configuration, while the clamping element 12 of the right connection terminal 10 is in its clamped configuration.

The arrangement of the clamping elements 12 of each of the two connection terminals 10 in either of their configurations is carried out by correspondingly and adaptively manipulating the associated actuating element 18.

According to a particular non-limiting embodiment, the change of the clamping element 12 from one configuration to another is performed by an integral displacement of the clamping element 12 with respect to the insulating housing 14, wherein the clamping element 12 is slidably mounted between a first position corresponding to the release configuration and a second position different from the first position and corresponding to the clamping configuration. Each clamping element 12 is housed and mounted so as to be slidable in a corresponding housing 19 defined by the insulating housing 14. Depending on the shape and structure of the housing 19, the sliding movement may or may not be linear, which ensures a guiding function of the clamping element 12 during its displacement. Thus, in the particular example shown, the insulating housing 14 delimits two housings 19, the two clamping elements 12 of the two connection terminals 10 being slidably mounted in the two housings 19. For a given connection terminal 10, the receiving port 15 of the first type opens into a corresponding housing 19.

For example, in fig. 1, the clamping element 12 of the left connection terminal 10 is in its second position, while the clamping element 12 of the right connection terminal 10 is in its first position. In fig. 3, the positions of the two clamping elements 12 are reversed with respect to the position assumed in fig. 1.

However, the fact remains that the change of each clamping element from one configuration to the other can be achieved in any other way, for example by a possible change of the shape of the clamping element 12.

According to a particular embodiment, the actuation element 18 comprises at least one threaded element, for example a screw or a bolt, which can be actuated from the outside of the insulating housing 14 and which, when screwed or unscrewed, ensures that the clamping element 12 is changed between the first position and the second position, and vice versa. However, the actuating element 18 may be constituted by any other equivalent and suitable means, in particular depending on the way in which the gripping element 12 is changed from one configuration to another. The clamping element 12 may comprise a complementary threaded element capable of cooperating with the threaded element of the actuating element 18. For example, in the case shown, if the threaded element of the actuating element 18 is a screw, the complementary threaded element may be a threaded port fixed to the clamping element 12, in which the screw engages.

Alternatively or additionally, it may be provided that the process of configuring one of the clamping elements 12 to the other is performed by an elastic member, for example a spring configured for this purpose and housed in the insulating housing 14.

The invention also relates to an electrical device itself, which is designed in particular to form the aforementioned junction box or contactor.

Claims

1. An electric apparatus comprising an insulating housing (14) and at least one connection terminal (10) mounted in the insulating housing (14), the connection terminal (10) comprising: a clamping element (12) formed of a non-magnetic material, the clamping element (12) being in the form of a cage capable of receiving an end of an electrical conductor (13) inserted into the clamping element (12); and an actuating element (18) allowing the clamping element (12) to be changed between a release configuration, in which the end of the electrical conductor (13) can be freely inserted into the clamping element (12) or removed from the clamping element (12), and a clamping configuration, in which the end of the electrical conductor (13) previously inserted into the clamping element (12) is held in position by clamping between the clamping element (12) and a conductive strip (11) of the electrical apparatus so as to establish an electrical contact between the conductive strip (11) and the end of the electrical conductor (13), the clamping element (12) being constituted by a single-piece integral piece; wherein the non-magnetic material is configured such that, under thermal effects caused by a magnetic field induced by an electric strength of more than 100A circulating in the electrical conductor (13), the clamping element (12) has a spatially deformed state such that, in the clamping configuration, the clamping element (12) prevents the end of the electrical conductor (13) from moving out of the clamping element (12), and the insulating housing (14) comprises: at least one receiving port (15) of a first type, in which receiving port (15) the end of the electrical conductor (13) tapers until it is inserted into the clamping element (12); and at least one receiving port (16) of a second type, the receiving port (16) of the second type allowing the insertion of another electrical conductor into the insulating casing (14), and the electrical apparatus comprising a bypass strip (17), the bypass strip (17) being configured to electrically link the electrically conductive strip (11) and the electrical conductor inserted into the receiving port (16) of the second type.

2. The electrical device of claim 1, wherein the electrical device is a junction box or a contactor.

3. An electrical device according to claim 1 or 2, wherein the non-magnetic material is a copper-based alloy, aluminium or an aluminium-based alloy.

4. The electrical apparatus according to claim 1 or 2, wherein the single-piece integral piece is obtained by a pressing operation.

5. An electric device according to claim 1 or 2, characterized in that the clamping element (12) is in the form of a profiled section having a cross section with a closed profile.

6. An electric device according to claim 1 or 2, characterized in that at least a part of the thickness of the clamping element (12) is between 2mm and 4 mm.

7. The electrical apparatus according to claim 1 or 2, characterized in that the change of the clamping element (12) from one configuration to another is performed by an integral displacement of the clamping element (12) with respect to the insulating housing (14), wherein the clamping element (12) is slidably mounted between a first position corresponding to the released configuration and a second position different from the first position and corresponding to the clamped configuration.

8. The electrical apparatus according to claim 7, characterized in that the actuation element (18) comprises at least one threaded element which can be actuated from outside the insulating housing (14) and which, when screwed or unscrewed, ensures the change of the clamping element (12) between the first position and the second position, and vice versa.