GB1581751A

GB1581751A - Electromagnetic contactors

Info

Publication number: GB1581751A
Application number: GB1738977A
Authority: GB
Original assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Priority date: 1976-04-28
Filing date: 1977-04-26
Publication date: 1980-12-17
Also published as: CH613807A5; FR2349944A1

Abstract

The switching contactor has a magnetic core (12), which is firmly anchored in its housing (10) and is formed from layers of core laminates, and a winding (14) which is mounted thereon and is held by a winding former (13). The magnetic core (12) is mounted in the housing (10) by means of at least one spring clip (16), which is of approximately U-shaped construction, engages, at right angles to the plane of the layers of the core laminates, around the magnetic core (12) and the winding (13, 14) mounted thereon and is suspended on or latched into studs (23, 24) or eyes which are connected to the housing (10). The spring clip (16), which consists, for example, of spring-tempered material with a round or rectangular cross-section, can have on its centre limb (20) a formed projection which points towards its clip ends (21, 22) and is preferably curved. In addition, a damping element (26) consisting of elastomeric material can be arranged between the winding (14) or winding former (13) and the magnetic core (12), which damping element (26) together with the spring clip (16) carries out a mass-compensating and damping function. <IMAGE>

Description

(54) ELECTROMAGNETIC CONTACTORS (71) We, BROWN, BOVERI & CIE.

A.G., a German Company of D6800 Mannheim-Kafertal, Kallstadter Strasse 1, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be preformed, to be particularly described in and by the following statement: The invention relates to an electromagnetic contactor having an electromagnet formed of a laminated core firmly anchored in the contactor casing and a winding mounted around the core.

Retaining the magnet cores in contactors always presents problems because the magnet cores themselves and the windings mounted thereon are always subject to substantial dimensional deviations and because the contactor may be subjected to substantial vibration. In known contactors, more particularly those of small construction, anchoring in the casing is achieved either by screw-mounting or by wedging between appropriate' casing projections or by pinning on separate parts which in turn are connected in suitable manner to the 'casing.

The present invention seeks to provide a contactor in which the mounting for the core and yoke. by contrast with known mountings, is simple, inexpensive, easy to install, readily detachable and capable of allowing for dimensional tolerance of the magnet core.

According to the present invention there is provided an electromagnetic contactor having a laminated magnet core and yoke mounted within a casing and a winding mounted on the core in which the core and yoke is secured in the' casing by means of at least one generally 'U shaped spring bow the free ends of the limbs of which are anchored to the casing and the base of which engages the core and yoke, the plane of the or each spring bow being substantially ptr- pendicular to the core and yoke laminations. A spring bow of this kind can be simply' and inexpensively manufactured and if suitably constructed can be installed without tools.

Preferably, the base of the or each spring bow has an arcuate portion the convex side of which faces towards the core and yoke.

Such arcuate shaping is particularly suitable for accommodating dimensional tolerance of the magnet core and to permit installation without tools. This also provides slack-free magnet core retention which is not impaired even after a large number of switching operations and the vibrations associated therewith but instead is able to dampen the vibrations.

It is convenient to construct the spring bows of spring wire of round or rectangular cross-section, because such starting materials are commercially obtainable in endless lengths.

Conveniently, the middle base of the or each spring bow is received in recesses in the core and yoke laminations said recesses being shaped to conform to the cross-section of the spring bow. This permits a particularly reliable and defined retention of the magnet core.

Advantageously, the ends of the spring bow or bows are anchored by engagement with eyelets or fins formed integrally from the material of the casing.

In a preferred embodiment of the invention, at least one damping element of elastic material is disposed between the winding or a coil former which accommodates the winding and the core whereby to damp vibration and accommodate dimensional tolerances of the core. The addition of a damping element can be performed simply and at low cost and in addition to the advantage bf some noise reduction also offers the advantage of a longer service life expectation of mechanically stressed parts.

Furthermore, dimensions of components or wall parts which are mechanically stressed by the vibrations can be reduced and their construction can be simplified (for example by dispensing with stiffening ribs).

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure I is partly sectioned a partial view of an electromagnetic contactor.

Figure 2 is a section taken along the line A B in Figure 1.

Figure 3 is a view corresponding to Figure 1 of a contactor of the kind shown in Figures 1 and 2 but having additional damping elements.

Figure 4 is a section through a contactor equipped with damping elements, the section being taken on line C - D in Figure 3.

Figure 5 is an exploded view of a magnet core with two differently constructed damping elements and a coil former, and Figure 6 is an exploded view of a magnet core with a frame shaped damping element and a coil former.

Figure 1 shows a contactor having a two-part casing comprising a casing shell or base 10 and a lid 11. The contactor comprises inter alia a magnet core and yoke 12, which is fixedly mounted on the casing shell 10 a coil former 13, mounted thereon and having a winding 14 and a movable armature 15. Figure 1 only partially shows a spring bow or strap 16 a small region of which is visible between the core and yoke 12 and the armature 15 and whose round cross-section is again represented in the illustration on the left-hand side of the core 12. The bow 16 may alternatively be made of wire rectangular section. The spring bow 16 engages in complimentary shaped recesses 17 which are punched into the laminations of the core and yoke 12. The armature 15 is assembled from completely identical lamination and consequently the armature has similar recesses which are referenced with the numeral 18. Mention should finally be made of a fin 19 which is formed from the material of the casing shell 10 and into which the abovementioned spring bow 16 latches but this is not disclosed in Figure 1.

The other parts shown in Figure 1 are not essential to an understanding of the present invention and will not be described in detail.

Figure 2 shows a view into the contactor turned through 9() in relation to the view shown in Figure 1 and sectioned, the section line being indicated in Figure 1 and designated A - B. The casing shell 10 and the lid 11 can be seen as well as the core and yoke 12, the coil former 13 mounted thereon with the winding 14 and the armature 15. The construction of the spring bow 16 is also clearly visible in this illustration. It has an approximately U-shaped configuration and its middle member or base 20 has an arc which is convex towards the ends 21 and 22 of the bow. The ends 21 and 22 of the spring bow 16 are inwardly bent and grip behind suitably shaped noses 23 and 24 of the fins 19 and a further fin 25. As already mentioned above the fins 19 and 25 are component parts of the casing shell 10 and are formed from the wall material thereof.

The method of mounting the spring bow 16 is believed to be clear from the drawing of Figure 2 and requires no further explanation. However it should be mentioned that the core and yoke 12 including the coil former and the winding 14 is anchored to the casing shell 10 by means of two spring bows 16 of which however only one is shown in the illustrations.

Figure 3 is an identical view to that of Figure 1 of a contactor which is generally similar to that shown in Figure 1 except for the provision of a damping element 26. All parts already described by reference to Figures 1 and 2 have been allocated the same numerals. The additional damping element 26, which is disposed between the coil former 13 and the core and yoke 12 as shown, assists the spring bow 16 in coping with dimensional tolerance and at the same time dampens vibrations which accompany the switching operation and thus also dampens the resultant noise.

Figure 4 is a view of the circuit breaker illustrated in Figure 3, said being sectioned and turned throughh 90" in relation to the view shown in Figure 3, the section being taken on line C-D in Figure 3. Identical numerals are used in this view for identical parts such as those explained in the previously described ilustrations. The damping element 26 can again be seen and it should be noted that two damping elements are present though only one of them is shown in the drawings.

Figure 5 is an exploded view of a core and yoke 27, a truncated coil former 28 and two differently constructed damping elements 29 and 30 disposed there between. The damping element 29 has projections 31 and 32 on oppositely disposed sides, extending approximately at right angles to the bearing surfaces but the damping element 30 is a strip of constant width bent into a U-shape.

The abovementioned angular projections 31 and 32 as well as the limbs of the U-shaped damping element 30 are provided to ensure a captive configuration in the assembled state of the components thus provided a simple alternative to the possibilty of bonding to one of the adjacent components.

Figure 6 shows an alternative solution for the construction of damping elements. This illustration shows between a magnet core and yoke 33 and a coil former 34 (only partially shown) a damping element 35 of picture frame like construction. Oppositely disposed surface parts 36 and 37 of the damping element 35 function as dimensional equalizing and damping surface and the other two frame sides 38 and 39 on the other hand are provided to retain together the abovementioned surface parts 36 and 37.

The advantage of such a construction is that the entire damping element 35 is captively retained in the assembled state; there is also the advantage that only a single part is required to achieve the damping and dimensional equalizing function and finally there is the advantage that the said part can be produced from flat material and can for example be punched out. In the assembled state the middle member 40 of the magnet core and yoke 33 extends through the central opening 41 in the damping element 35 and retention and captive configuration of the parts is thus ensured without any further steps.

The damping elements may be of a porous rubber or plastics material.

To achieve a long service life it can also be more advantageous to select a non-porous material provided with recesses in the form of edge notches and/or perforations instead of using material of a porous structure. In this way it is possible to confer on an intrinsically not excessively soft material the characteristics of a distinctly soft rubber or of a porous material.

WHAT WE CLAIM IS: 1. An electromagnetic contactor having a laminated magnet core and yoke mounted within a casing and a winding mounted on the core in which the core and yoke is secured in the casing by means of at least one generally 'U' shaped spring bow the free ends of the limbs of which are anchored to the casing and the base of which engages the core and yoke, the plane of the or each spring bow being substantially perpendicular to the core laminations.

2. An electromagnetic contactor as claimed in Claim 1, in which the base of the or each spring bow has an arcuate portion the convex side of which faces towards the core and yoke.

3. An electromagnetic contactor as claimed in Claim 1 or 2. in which the or each spring bow is formed of spring wire of round section.

4. An electromagnetic contactor as claimed in Claim 1 or 2, in which the spring bow is formed of spring wire of rectangular cross-section.

5. An electromagnetic contactor as claimed in any of Claims 1 to 4. in which the base of the or each spring bow is received in recesses in the core and yoke laminations said recesses being shaped to conform to the cross-section of the spring bow.

6. An electromagnet contactor as claimed in any of Claims 1 to 5, in which the ends of the spring bow or bows are anchored by engagement with eyelets or fins formed integrally from the material of the 'casing.

7. An electromagnetic contactor as claimed in any of Claims 1 to 6, in which:the magnet core is secured in the casing by means of two spring bows.

8. An electromagnetic contactor as claimed in any preceding claim which at least one damping element of eleastic material is disposed between the winding or a coil former which accomodates the winding and the core whereby to damp vibration and accommodate dimensional tolerances of the core and yoke.

9. An electromagnetic contactor as claimed in Claim 8 having an E-shaped core and yoke the middle limb of which is surrounded by the winding, in which a respective damping element is provided in between each pair of adjacent limbs, each damping element having a flat portion normal to the winding axis.

10. An electromagnetic contactor as claimed in Claim 8 or 9, in which the damping elements are constructed in sheet form and a surface of each damping is bonded the core and/or to the winding or the coil former.

11. An electromagnetic contactor as claimed in Claim 9, in which each damping element has projections which are inclinded at an angle to the said flat portion and straddle the core lamination.

12. An electromagnetic contactor as claimed in Claim 11, characterized in that the damping elements are substantially Ushaped.

13. An electromagnetic contactor as claimed in claim 8, having an 'E' shaped core and yoke the middle limb of which is surrounded by the winding, in which the damping is a sheet formed with an aperture through which the middle limb of the core passes.

14. An electromagnetic contactor as claimed in any of Claims 8 to 13, in which the damping element(s) consist(s) of a porous rubber or plastics material.

15. An electromagnetic contactor as claimed in any of the Claims 8 to 13, in which the damping element surfaces for damping have recesses in the form of edge notches and/or perforations.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. picture frame like construction. Oppositely disposed surface parts 36 and 37 of the damping element 35 function as dimensional equalizing and damping surface and the other two frame sides 38 and 39 on the other hand are provided to retain together the abovementioned surface parts 36 and 37. The advantage of such a construction is that the entire damping element 35 is captively retained in the assembled state; there is also the advantage that only a single part is required to achieve the damping and dimensional equalizing function and finally there is the advantage that the said part can be produced from flat material and can for example be punched out. In the assembled state the middle member 40 of the magnet core and yoke 33 extends through the central opening 41 in the damping element 35 and retention and captive configuration of the parts is thus ensured without any further steps. The damping elements may be of a porous rubber or plastics material. To achieve a long service life it can also be more advantageous to select a non-porous material provided with recesses in the form of edge notches and/or perforations instead of using material of a porous structure. In this way it is possible to confer on an intrinsically not excessively soft material the characteristics of a distinctly soft rubber or of a porous material. WHAT WE CLAIM IS:

1. An electromagnetic contactor having a laminated magnet core and yoke mounted within a casing and a winding mounted on the core in which the core and yoke is secured in the casing by means of at least one generally 'U' shaped spring bow the free ends of the limbs of which are anchored to the casing and the base of which engages the core and yoke, the plane of the or each spring bow being substantially perpendicular to the core laminations.

16. An electromagnetic contactor sub

stantially as herein described with reference to and as illustrated in Figures 1 and 2 or Figures 3 and 4, or Figures 5 or 6 of the accompanying drawings.