FIELD OF THE INVENTION
The present invention relates to an electromagnetic switching device, and more particularly, to a yoke assembly for an electromagnetic switching device.
BACKGROUND
Known electromagnetic switching devices have yoke assemblies commonly including two legs connected to each other via a bend. One of the legs has an electromagnetic element, for example a coil wound around the leg. By energizing the coil, electromagnetic flux is induced into the yoke. An armature is disposed at the ends of the legs opposite the bend, the armature being pulled towards the ends of the legs upon energizing the coil. When the armature abuts the ends of the legs, a magnetic circuit is closed and, consequently, the armature is held at the ends of the legs of the yoke. An actuating assembly including the armature further comprises an actuator mechanically interacting with at least one switching contact of the switching device. Upon energizing the coil, the switching contact may be moved from a first position into a second position, where it is brought in electrical contact with at least one contact element of the switching device.
Electromagnetic switching devices known in the art have the disadvantage that the actuating assembly and the switching contacts produce a noise when impinging an abutment face of the yoke and the counter contact, respectively. Further, when moving back from the energized second position into the de-energized first position, the actuating assembly impinges upon the yoke and/or a housing of the switching device. Switching noise from the respective impacts has an adverse effect both acoustically and through mechanical vibration, especially when the electromagnetic switching device is used in industrial applications where multiple electromagnetic switching devices may be arranged next to each other, amplifying the switching noises.
SUMMARY
A yoke assembly for an electromagnetic switching device according to the invention comprises a yoke and an elastic deceleration element. The yoke has a support face supporting an abutment face of an actuating assembly in a position of the switching device. The elastic deceleration element is mounted on the yoke and has a deceleration face disposed at a distance from the support face.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example with reference to the accompanying figures, of which:
FIG. 1 is a side view of an electromagnetic switching device according to the invention;
FIG. 2 is a side view of a yoke assembly of the electromagnetic switching device of FIG. 1;
FIG. 3 is a top view of the yoke assembly of FIG. 2;
FIG. 4 is a front view of the yoke assembly of FIG. 2; and
FIG. 5 is a graph of a deceleration effect of the electromagnetic switching device of FIG. 1.
DETAILED DESCRIPTION OF THE EMBODIMENT(S)
Exemplary embodiments of the present invention will be described hereinafter in detail with reference to the drawings, wherein like reference numerals refer to like elements. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art.
A switching device 1 according to the invention is shown in FIG. 1. The switching device 1 includes a switching assembly 2, a drive unit 3, an actuating assembly 4, and a yoke assembly 5. The switching assembly 2, the drive unit 3, the actuating assembly 4, and the yoke assembly 5 are mounted on a base 6 of the switching device 1. The switching device 1 further includes a guidance 8 for the actuating assembly 4, the guidance 8 disposed on a frame 7 of the switching device 1.
The switching device 1, as shown in FIG. 1, extends along a longitudinal direction X, a transverse direction Y, and a height direction Z, which run perpendicularly to each other and thus form a Cartesian coordinate system. Henceforth, any mention of front or rear relates to the longitudinal direction X, mentions of left and right relate to the transverse direction Y, and mentions of above and below relate to the height direction Z.
The switching assembly 2, as shown in FIG. 1, includes a switching contact 20 having a first contact element 20a and a second contact element 20b. The first and second contact elements 20a, 20b have a first contact face 21a and a second contact face 21b, respectively, which face in a first switching direction Sa and a second switching direction Sb, respectively. In order to be moveable in the first switching direction Sa and the second switching direction Sb, the first and second contact elements 20a, 20b are mounted on a displaceable switching contact carrier 22. In the embodiment shown in FIG. 1, the switching contact carrier 22 is a leaf spring that has a holding section 23 electrically connected to a connecting section 24. The switching contact 20 is electrically connected through the connecting section 24 to a connecting element of a device carrying or containing the switching device 1.
The switching assembly 2, as shown in FIG. 1, has a first counter connecting section 25a and a second counter connecting section 25b electrically connected to a first counter contact 26a and a second counter contact 26b, respectively. The first counter contact 26a and the second counter contact 26b have a first counter contact element 27a and a second counter contact element 27b, respectively. The first counter contact element 27a has a first counter contact face 28a and the second counter contact element 27b has a second counter contact face 28b. The first counter contact 26a is mounted on a first counter contact carrier 29a and the second counter contact 26b is mounted on a second counter contact carrier 29b. The first counter contact carrier 29a is electrically connected to the first counter connecting section 25a and the second counter contact carrier 29b is electrically connected to the second counter connecting section 25b.
The drive unit 3, as shown in FIG. 1, has at least one supply contact element 30 for providing the drive unit 3 with electrical energy. The actuating assembly 4 is moved by interacting with the yoke assembly 5 upon energizing and de-energizing the drive unit 3 via the at least one supply contact element 30. In a second position B of the switching device 1 shown in FIG. 1, the drive unit 3 is in an idle state and the second contact face 21b of the second contact element 20b abuts the second counter contact face 28b of the second counter contact element 27b, so that the connecting section 24 and the second counter connecting section 25b have the same electrical potential. In a first position A of the switching device 1, the drive unit 3 is in an energized state.
The actuating assembly 4, as shown in FIG. 1, has an armature 40 which is hinged to or at least movably held in the vicinity of the yoke assembly 5 such that the armature 40 is movable with respect to the yoke assembly 5. For abutting the yoke assembly 5, the armature 40 has an abutment face 41a that faces in the first switching direction Sa. The armature 40 also has a coupling section 42, with which the armature 40 engages a coupling member 43 of an actuator 44 of the actuating assembly 4. The actuator 44 is slidably held in the first switching direction Sa and the second switching direction Sb along the guidance 8 provided by or fixed on the frame 7.
A switching member 45 of the actuating assembly 4, as shown in FIG. 1, is connected to the actuator 44 and engages the holding section 23 of the switching contact 20. The switching member 45 has a plurality of holding elements 46 engaging the holding section 23. In order to transfer switching forces onto the holding section 23 of the switching contact 20, a first actuating face 47a facing essentially in the first switching direction Sa and/or a second actuating face 47b facing essentially in the second switching direction Sb are disposed at the switching member 45. The actuator 44 also has a stop face 48 for stopping movements of the actuator 44 in the second switching direction Sb. An end face 49 of the actuator 44 stops movement of the actuator 44 and thereby of the actuating assembly 4 in the second switching direction Sb.
The yoke assembly 5, as shown in FIGS. 1 and 2, has a yoke 50 including a first leg 51 and a second leg 51′. The first leg 51 and the second leg 51′ extend essentially in parallel to each other along the longitudinal direction X and, therefore, along the switching directions Sa, Sb. The first leg 51 has a first support face 51a and a second support face 51b which face in directions opposite to the first switching direction Sa and the second switching direction Sb, respectively. As shown in FIG. 1, the first support face 51a supports the abutment face 41a of the armature 40 and the second support face 51b supports the stop face 48 of the actuator 44.
An elastic first deceleration element 52a and an elastic second deceleration element 52b are mounted on and/or attached to the yoke 50, in particular the first leg 51 thereof, as shown in FIG. 2. The first deceleration element 52a and the second deceleration element 52b are integrally formed of a metal or a metal alloy. In one embodiment, the first deceleration element 52a and the second deceleration element 52b are formed of stainless steel or phosphor bronze. The first deceleration element 52a and the second deceleration element 52b may be welded or soldered to the yoke 50.
The first deceleration element 52a has a first deceleration face 53a facing essentially opposite to the first switching direction Sa and a first spring section 54a via which a first cushioning section 55a is connected to a first mounting section 56a of the first deceleration element 52a mounted to the first leg 51. The second deceleration element 52b has a second deceleration face 53b facing essentially opposite to the second switching direction Sb and a second spring section 54b via which a second cushioning section 55b is connected to a second mounting section 56b of the second deceleration element 52b mounted to the first leg 51.
As shown in FIG. 2, the first mounting section 56a of the first deceleration element 52a is connected to a first mounting region 57a of the yoke 50 and the second mounting section 56b of the second deceleration element 52b is connected to a second mounting region 57b of the yoke 50. The first mounting section 56a faces opposite to the first switching direction Sa and the first mounting region 57a faces in the first switching direction Sa. The second mounting section 56b and the second mounting region 57b face in directions perpendicular to the switching directions Sa, Sb, opposite and in the height direction Z, respectively. The first deceleration face 53a and the second deceleration face 53b are disposed at the first cushioning section 55a and the second cushioning section 55b, respectively.
The yoke 50 also has an extension 50′ as shown in FIG. 2 which is formed at or attached to the first leg 51 and extends essentially perpendicular to the switching directions Sa, Sb. The support faces 51a, 51b of the first leg 51 and the mounting regions 57a, 57b of yoke 50 are disposed at the extension 50′. The first leg 51 and the second leg 51′ are connected to each other via a bend 51″. A recess 58b is disposed between the extension 50′ and the first leg 51, the recess 58b at least partially accommodating the second spring section 54b of the second deceleration element 52b.
As shown in FIG. 3, the first deceleration face 53a of the first deceleration element 52a protrudes from the first support face 51a opposite to the first switching direction Sa. The second deceleration face 53b of the second deceleration element 52b is held at a distance from the second support face 51b opposite to the second switching direction Sb. The first deceleration element 52a interleaves with the second deceleration element 52b in that the first deceleration element 52a, in particular the first cushioning section 55a thereof, extends through a cut-out 59 formed in the second deceleration element 52b, in particular the spring section 54b and/or second cushioning section 55b thereof. As shown in FIG. 4, the cut-out 59 also extends through the extension 50′ of the yoke 50 and forms an opening 58a through which the first cushioning section 55a and thus the first deceleration face 53a of the first deceleration element 52a may be displaced in the first switching direction Sa. The opening 58a, as shown in FIG. 4, is a through-hole 58 extending through the first support face 51a of the yoke 50.
The switching contact 20 is transferable by the drive unit 3 in a closing direction from the second position B, wherein the drive unit 3 is in the idle state, to the first position A, wherein the driving unit 3 is in the energized state. In the first position A, the switching contact 20 abuts the first counter contact 26a in an electrically conductive manner, and in the second position B, the switching contact 20 abuts the second counter contact 26b in an electrically conductive manner.
During motion from the second position B to the first position A, moving along the first switching direction Sa, the abutment face 41a of the actuating assembly 4 impinges on the first deceleration face 53a of the first deceleration element 52a protruding from the first support face 51a before impinging on the first support face 51a of the first leg 51, as shown in FIGS. 1 and 2. The first deceleration face 53a is elastically displaceable at the first spring section 54a, and consequently absorbs energy of the actuating assembly 4 and switching contact 20, slowing motion of the actuating assembly 4 in the first switching direction Sa. The actuating assembly 4 is thus decelerated before arriving at the yoke 50 and an impact noise between the actuating assembly 4 and the yoke 50 is significantly reduced. The switching contact 20 connected to the actuating assembly 4 is also decelerated before the second contact element 20b arrives at the second counter contact 26b and an impact noise between the second contact element 20b and the second counter contact 26b is significantly reduced. In the first position A, the abutment face 41a still lies flush against the first support face 51a of the first leg 51 and, consequently, the deceleration effect of the first deceleration face 53a of the first deceleration element 52a does not compromise the switching of the switching device 1.
During motion from the first position A to the second position B, moving along the second switching direction Sb, the stop face 48 of the actuator 44 impinges on the second deceleration face 53b of the second deceleration element 52b held at a distance from the second support face 51b before impinging on the second support face 51b of the first leg 51, as shown in FIGS. 1 and 2. The second deceleration face 53b is elastically displaceable at the second spring section 54b, and consequently absorbs energy of the actuating assembly 4 and switching contact 20, slowing motion of the actuating assembly 4 in the second switching direction Sb. The actuating assembly 4 is thus decelerated before arriving at the yoke 50 and an impact noise between the actuating assembly 4 and the yoke 50 is significantly reduced. The switching contact 20 connected to the actuating assembly 4 is also decelerated before the first contact element 20a arrives at the first counter contact 26a and an impact noise between the first contact element 20a and the first counter contact 26a is significantly reduced. In the second position B, the stop face 48 still lies flush against the second support face 51b of the first leg 51, and consequently, the deceleration effect of the second deceleration face 53b of the second deceleration element 52b does not compromise the switching of the switching device 1.
The first deceleration element 52a and the second deceleration element 52b, as shown in FIGS. 2 and 3, are disposed symmetrically with respect to a plane extending perpendicularly to the first deceleration face 53a and the deceleration face 53b, respectively. Thereby, forces to be absorbed by the first deceleration element 52a and the second deceleration element 52b as described above are evenly distributed and the actuating assembly 4 moves in parallel to the switching directions Sa, Sb during deceleration.
Deceleration forces of the first deceleration element 52a and the second deceleration element 52b during transfer of the switching contact 20 by the drive unit 3 are shown graphically in FIG. 5. The dashed and dotted lines show force exerted by the drive unit 3 at the extension 50′ of the yoke 50 upon energizing the drive unit 3 with a pull-in voltage in the second position B shown in FIG. 1. The force (AW-curve) increases when moving the actuating assembly 4 along the first switching direction SA until reaching the first position A. The dashed line illustrates a force over distance diagram (F-s curve) which would be exerted from the yoke assembly 5 on the actuating assembly 4, in particular on the armature 40 thereof, when no deceleration element 52a, 52b is present. The area between the dashed and dotted AW-curve and the dashed F-s curve is equivalent to the impulse of the actuating assembly 4. By adding at least one deceleration element 52a, 52b, the dashed F-s curve is transferred into the solid F-s curve showing that the impulse and thus impact noise of the actuating assembly 4 on the yoke assembly 5 is significantly reduced.
The switching device 1 may have switching assemblies 2, drive units 3, actuating assemblies 4, yoke assemblies 5, bases 6, frames 7 and guidances 8 in any form or number desired for performing the switching of electrical currents.
Patent Grant
10679813
