Electromagnetic relay

An electromagnetic relay is disclosed. The electromagnetic relay comprises a coil, a yoke having a yoke face, and an armature. The armature has an armature face facing the yoke face and movable, depending on a current through the coil, between an open position and a closed position in which the armature face is positioned closer to the yoke face, and an overlap disposed over a side surface of the yoke. A first distance between the side surface of the yoke and the overlap is smaller than a smallest second distance between the armature face and the yoke face in the open position.

FIELD OF THE INVENTION

The present invention relates to an electromagnetic relay, and more particularly, to an electromagnetic relay having a coil, a yoke, and a movable armature.

BACKGROUND

Electromagnetic relays having a coil, a yoke, and a movable armature are known in the prior art wherein the armature has an open position or a closed position depending upon a current running through the coil. The electromagnetic relay generates an electromagnetic force between the armature and the yoke. In the open position, the armature is further away from the yoke than in the closed position.

SUMMARY

An object of the invention, among others, is to provide an electromagnetic relay that, in the open position of the armature, forms a higher electromagnetic force between the yoke and the armature. The disclosed electromagnetic relay comprises a coil, a yoke having a yoke face, and an armature. The armature has an armature face facing the yoke face and movable, depending on a current through the coil, between an open position and a closed position in which the armature face is positioned closer to the yoke face, and an overlap disposed over a side surface of the yoke. A first distance between the side surface of the yoke and the overlap is smaller than a smallest second distance between the armature face and the yoke face in the open position.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

The invention is explained in greater detail below with reference to embodiments of an electromagnetic relay. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and still fully convey the scope of the invention to those skilled in the art.

An electromagnetic relay40according to the invention is shown generally inFIGS. 1-5. The electromagnetic relay40has a coil body1, a yoke3, and an armature7. The major components of the invention will now be described in greater detail.

The coil body1, as shown inFIGS. 1 and 4, has a support surface23, and retaining arms24,25disposed on each side of the support surface23. A coil20is disposed within the coil body1, and as shown inFIG. 1, the coil20is electrically connected to a connector41.

The yoke3, as shown inFIG. 1, is formed in a U-shape with a second arm2and a first arm4. The first arm4has a yoke face5, an upper side surface15, and an edge section26bordering the yoke face5and which leads to an increase of a height27of the first arm4. The yoke face5has a plurality of fixed contacts (not shown). The edge section26has an upper edge surface28, as shown inFIG. 3.

The armature7, as shown inFIGS. 1-3, has a lower end section9, an upper end section6, an overlap11, and a bar19. The upper end section6has an armature face10and an upper end surface12. As shown inFIG. 4, the upper end section6has a width30. The armature7is operatively connected to a movable contact (not shown).

The overlap11is a curved, angled section extending from a partial surface13of the upper end surface12of the upper end section6, the partial surface13being located in a front region of the upper end surface12. A rear region of the upper end surface12has an rear surface14. In the shown embodiment, the overlap11has a thickness of approximately half the thickness of the upper end section6. The overlap11could alternatively have a range of other thicknesses, including a thickness equal to the upper end section6; in this alternative embodiment, no rear surface14is formed. The overlap11can also project from the armature face10. The overlap11has a lower side surface16, as shown inFIG. 3.

The overlap11may extend from the whole width30of the upper end section6, or may extend from just a partial region of the width30. In addition, the overlap11can also be made in the form of a number of individual overlaps11arranged a distance apart from one another; the individual overlaps11can be distributed equal distances apart over the width30. For example, an overlap11can extend from at least 50% of the width30, or the overlap11could extend from at least 90% of the width30.

The bar19projects forward from the overlap11. The overlap11, as shown inFIG. 4, may have three bars19,21, and22projecting forward from the overlap11.

The assembly of the electromagnetic relay40will now be described in greater detail with reference toFIGS. 1-5.

As shown inFIG. 1, the second arm2of the yoke3extends through the coil body1and the coil20. A first arm4of the yoke3is located above the coil body1and leads out to over a front side of the coil body1.

The armature7is mounted with the lower end section9pivotably connected to the second arm3of the yoke3, as shown inFIG. 3, the lower end section9rotating about an axis of rotation8on the coil body1. The lower end section6of the armature7rests pivotably on the support surface23of the coil body1, as shown inFIG. 4. In addition, the retaining arms24,25prevent the armature7from tilting too far away from the yoke3.

The upper end section6of the armature7is positioned in front of the yoke face5in the open position shown inFIG. 1such that the armature face10faces the yoke face5, but is spaced apart from the yoke face5. The overlap11extends from the armature7towards the yoke face5, the overlap11extending through a first plane defined by the armature face10and a second plane defined by the yoke face5and being positioned above the first arm4.

The bars19,21, and22are provided in order to fasten a comb29to the armature7, as shown inFIG. 5. The comb29is designed to establish an operative connection between the electromagnetic relay40and a movable electric contact (not shown). In various embodiments, the comb29may be connected to more than one movable electric contact.

The electromagnetic relay40is shown in the open position of the armature7inFIGS. 1, 2, and 4, in which the yoke face5and the armature face10are spaced apart from one another by, at a minimum, a smallest second distance18. In this position, the overlap11may nevertheless overlap an upper side surface15of the first arm4. Between the upper edge surface28of the edge section26of the first arm4and a lower side surface16of the overlap11, a first distance17is formed that is smaller than the smallest second distance18. In the open position, the fixed contact (not shown) of the yoke face5and the movable contact (not shown) connected to the armature7are spaced apart from one another, and are not electrically connected. Due to the small first distance17, a relatively large electromagnetic flux is formed between the first arm4and the upper end section6in a de-energized state of the coil20.

FIG. 9shows the course of the magnetic flux of the open position shown inFIG. 1, the magnetic flux being illustrated with the aid of arrows. On the basis of the design of the overlap11, a magnetic flux38between the overlap11and the first arm4is formed over the first distance17.

The armature7is moved from the open position shown inFIG. 1to the closed position shown inFIG. 3when a current is run through the coil20. In the closed position, the fixed contact (not shown) of the yoke face5and the movable contact (not shown) connected to the armature7are in contact, producing an electric connection between the contacts. As shown inFIG. 3, in the closed position, the armature face10rests against the yoke face5. Likewise, the lower end section9of the armature7rests against the second arm2of the yoke3. The upper edge surface28of the edge section26faces the lower side surface16of the overlap11.

In the closed state, the overlap11no longer has any effect upon the electromagnetic flux. The closer the upper end section6comes to the yoke face5, the less significant the effect of the overlap11, because the second distance18continually decreases. As the upper end section6comes closer to the first arm4, the areas and cross sections which are responsible for guiding the magnetic flux increase.

Another embodiment of an electromagnetic relay40is shown inFIGS. 6 and 7. As shown inFIG. 6, a second overlap31and a third overlap32are formed, respectively, on a first lateral armature surface33and a second lateral armature surface34of the armature7. In the open state of the armature7, shown inFIGS. 6 and 7, the second overlap31and the third overlap32overlap a first lateral arm surface35and a second lateral arm surface36of the first arm4. In this embodiment, a small space17is formed between the armature7and the first arm4in relation to lateral side surfaces. This embodiment also generates an increased magnetic flux in the open state of the armature7. In alternative embodiments, just one additional overlap31,32may also be provided.

Another embodiment of an electromagnetic relay40is shown inFIG. 8. The armature7is shown inFIG. 8in the open position, the armature face10of the upper end section6being the second distance18away from the yoke face5of the first arm4. On opposing sides, the first arm4has a fourth and a fifth overlap42,43. The fourth and the fifth overlap42,43are arranged with the first distance17at the side next to the lateral surfaces33,34of the armature7. The first distance17is smaller than the second distance18. In alternative embodiments, just the fourth or the fifth overlap42,43may be provided.

In other embodiments, the armature7can have both an overlap11according to the description ofFIGS. 1 to 4and additional overlaps31,32according toFIGS. 6 and 7. The second and/or third overlap31,32may also just extend over a partial surface of the width of the lateral surfaces33,34of the armature7, in particular the upper end section6. The partial surface may be facing the yoke face5of the first arm4so that a rear region has an end surface.

Advantageously, according to the electromagnetic relay40of the present invention, in the open position of the armature7a higher magnetic and/or electromagnetic force acts between the armature7and the yoke3due to the small first distance17between them. Consequently, a de-energized contact force between the movable contact and the fixed contact in the closed position can be increased, also increasing a life span of the electromagnetic relay40. Furthermore, it is not necessary to provide the largest possible surface pairing of the face surfaces5,10of the yoke3and armature7that are opposite one another. The cross sections of the armature7and of the yoke3can therefore be made smaller. Additionally, the overlap in various embodiments enables simple manufacturing and a compact structure of the electromagnetic relay40.