Patent Application
20060066424
1. Field of the Invention
The present invention relates to an electromagnetic relay having a base in which connecting elements are anchored, a magnet system with a coil, a core arranged in the coil, an L-shaped yoke, and a plate-shaped armature. A first yoke leg is arranged essentially parallel to a coil axis and a second yoke leg is connected to a first end of the core. The armature is pivoted on the first yoke leg and forms a working air gap with the second end of the core. The relay further includes a contact system with a contact spring that carries a movable contact and is fastened to the armature, as well as at least one fixed contact carrier that carries a fixed contact and is anchored in the base.
2. Description of the Background Art
Conventional relays of this type are distinguished by compact construction and are used, e.g., to switch large currents, as for example in low-voltage circuits in automobiles and the like. In known relays of this type, it is frequently only possible through great effort to securely fasten the magnet system to the base and set the return force of the return spring.
It is therefore an object of the present invention to provide a relay such that a magnet system and a base with the contact system can be manufactured and joined together in a simple manner, whereby different embodiments of the coil and contacts can be created for different applications of the relay without great changes in the manufacturing process. The design of the relay must facilitate a favorable configuration of the contact connections and the coil connections in the smallest possible space while still ensuring the necessary insulating spacings between the connections. Moreover, the relay must be easy to assemble; in particular, the air gap between the armature and the coil core, as well as the return force of the return spring, must be adjustable by simple means.
In accordance with an embodiment of the present invention, this object is attained with a relay that has the following features:
The support of the first yoke leg on one side of the base surface or the anchoring of the forked ends of this first yoke leg in recesses in the base surface, and the additional support of the free end of the second yoke leg by at least one yoke support on the opposite side of the base, result in a very stable fastening of the magnet system, wherein the adjustment of the working air gap between the coil core and the armature can be carried out very precisely before the yoke support is joined to the second yoke leg. Instead of one yoke support, two or even more yoke supports can be provided, which are then supported at different places on the base if necessary. The at least one yoke support is preferably made of metal and is attached, preferably welded, to a connecting element anchored in the base. Consequently, the support is more reliable than in the case of exclusive support in the base, whose plastic has a different coefficient of thermal expansion than, for example, the metal of the magnet system. However, in order to avoid a short circuit, additional yoke supports should not be fastened to an additional connecting element.
The return spring for the armature extends between the forked ends of the first yoke leg and thus can be fixed to the yoke after the magnet system is assembled on the base; the return force can be set at the same time.
In an advantageous embodiment of the invention, the contact spring is connected by a stranded wire to a spring contact anchored in the base. In this context, the stranded wire can preferably be arranged below the armature in the shape of an arc that extends sideways across the entire width of the armature. In this way the stranded wire simultaneously serves to limit the stroke of the armature.
In a special embodiment of the invention, the connecting elements, in particular the contact connecting elements, can have fork-shaped divided ends. In this way, the relay can be plugged onto rail-shaped electrical supplies. The forked ends are then preferably elastically resilient or are provided with elastically resilient sections in order to ensure the desired plug contact force.
In an alternate embodiment of the present invention a relay includes the following features:
In order to adjust the return force during installation of the return spring, an adjusting screw can be used that could be screwed into the yoke leg to a greater or lesser degree to bring the return spring closer to the outer side of the yoke leg in the desired manner and thus preload the return spring. Such an assembly process would be very complicated, however. Therefore, an advantageous refinement of the invention provides a boss, for example a stamped boss, that extends outward from the yoke leg; a hole in the return spring is pushed onto the boss until the desired return force is reached, and is then fixed in the position thus reached. To this end, for example, the boss can be deformed by orbital riveting until the return spring has reached the end position. In another, particularly advantageous embodiment, a hole in the return spring can have a smaller diameter than the boss, the edge of the hole being interrupted by slits arranged in a ray-like manner to form spring tabs. For adjustment, the hole in the return spring is then pressed onto the boss until the desired return force is achieved. In this position, the tabs spread around the circumference of the boss and ensure the fastening of the return spring on the boss.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
The relay shown in
The armature 6 is held by an armature spring 7 which serves as a contact spring with a contact section 7a and as a return spring with a return section 7b. The contact section 7a is connected to the armature, for example by riveting or other means. The center section of the armature spring 7 has a curved section 7c with which it engages around a pivot point of the armature on the first yoke leg 4. The contact section 7a encloses an angle of more than 90° with the fastening section, at least in the relaxed state, so that the contact section with the armature 6 is held away from the core end 3b in the rest state of the magnet system when the return section 7b is fastened to the outer side of the yoke leg 4.
For fastening the armature spring 7, the yoke leg 4 has a boss 8 extending outward, which can for example be produced by stamping. For fastening on the boss 8, the return leg 7b has a hole 9 whose diameter is slightly less than the diameter of the boss 8. Moreover, multiple slits extend outward from the circumference of the hole 9 in a ray-like or cruciform manner, forming four spring tabs 9a in the example shown. Naturally, the number of slits and spring tabs could also be different from four. When the return leg 7b is pressed onto the boss 8 with force, the spring tabs 9a are resiliently bent outward, and they catch in the circumference of the boss 8 such that the return leg 7b is secured against being pushed back.
Two coil connecting elements 10 are anchored in the base. Moreover, in the present example the base carries two contact connecting elements, namely a spring connection 11 and a fixed contact connection 12. All connecting elements are anchored by being inserted in slots in the base 1, and if necessary, by notches 13. The spring connection 11 is connected through a stranded wire 14 to a spring contact or movable contact 15 at the free end of the contact section 7a. The stranded wire 14 lies below the armature 6 in the shape of an arc; in this way, the stroke of the armature 6 is limited without additional means. The fixed contact connection 12 carries at its angled free end a fixed contact 16 which forms a switch contact pair together with the spring contact 15. Also fastened to the spring connection 11 is a yoke support 17 made of sturdy steel wire, which is located parallel to the first yoke leg 4 on the opposite side of the coil. An additional support could also be provided at the other corner of the yoke leg 5; however, in order to avoid a short circuit, this additional support must not be connected to the other contact connection.
During assembly of the relay, the base assembly (see
To fasten the armature spring 7 and to set the armature return force, the return leg 7b is then pressed onto the boss 8 as shown in
Another possibility for fastening and setting the armature spring is shown in
As can be seen from
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
