Patent Application
20130192934
The following documents are incorporated herein by reference as if fully set forth: German Patent Application No.: 202012000897.8, filed Jan. 31, 2012.
The invention relates to a spring pressure brake having a magnet housing which has an annular receiving space for an electromagnetic coil and can be connected by fastening screws to a housing of a drive, having a non-rotatable armature disk which is arranged coaxially with respect to the electromagnetic coil and is made from magnetically conducting material, having a rotor disk which is arranged coaxially with respect to the armature disk and serves as brake disk, and having a non-rotatable mating disk which serves as abutment for the brake or rotor disk, the spring pressure brake having a central compression spring or individual compression springs which are arranged at a radial spacing from the longitudinal center axis in order to generate the brake pressure between the armature disk, brake disk and mating disk when current is not applied to the electromagnetic coil, and fastening screws being provided for connecting the magnet housing to a holding device, a housing or a flange for the mating disk.
A spring pressure brake of this type is known from DE 102006010656 B3 and has proven itself.
A comparable spring pressure brake is known from DE 4031245 A1.
A comparable spring pressure brake is likewise known from DE 198 38 171 A1. Here, the pot magnet which can be magnetized and to this end receives the electromagnetic coil has a flange which is connected integrally to it and is penetrated by fastening screws which at the same time penetrate a plastic sleeve which belongs to the housing of said spring pressure brake and is arranged coaxially with respect to the pot magnet.
Above all in the cases, in which the spring pressure brake is to have comparatively small or low dimensions, because only a limited space is available to accommodate it, the weight of spring pressure brakes which are constructed in this way in a known manner is relatively high. Moreover, there are frequently leakage fluxes and magnetic losses at the magnet housing, above all. Losses of this type can be produced as a result of the fact that the fastening of the spring pressure brake itself also has to act on the magnet housing, that is to say the abovementioned fastening screws are provided, as is known, for example, from DE 198 38 171 A1 which is mentioned above. Moreover, the radially outwardly oriented flange of the magnet housing requires additional space in the radial direction.
Moreover, the compression springs can require additional space, in particular in the case of an arrangement at a radial spacing from the longitudinal center axis, as a result of which the magnet housing is enlarged, which in turn can increase the risk of leakage fluxes and magnetic losses.
It is therefore the object to provide a spring pressure brake of the type defined at the outset, in which the risk of magnetic or leakage losses can be reduced or avoided as far as possible.
In order to achieve this object, the spring pressure brake which is defined at the outset is distinguished by the fact that at least the magnet housing consists of at least two parts, the first part of which has, as pot magnet, the annular receiving space for the magnetic coil and which is comprised of magnetizable material, and that the second part of the magnet housing is connected to the first part, has the fastening points for the fastening screws and is comprised of a non-magnetizable material, that second part of the magnet housing which is comprised of non-magnetizable material having, on its outer circumference, holes or projections or cross-sectional widened portions which are oriented in the axial direction for the fastening screws, and that the first part of the magnet housing is bore-free or hole-free in the sense that it is not loaded by the fastening screws.
The result of the surprising assembly of the magnet housing firstly from the pot magnet made from magnetizable material and secondly a further part made from non-magnetizable material is a reduction in the magnetizable mass, with the result that the risk of leakage fluxes and/or magnetic losses is correspondingly reduced or even avoided.
The reduced mass of magnetizable material results in the additional advantage that the spring pressure brake according to the invention can react more rapidly to the current for the electromagnetic coil being switched on or off, because a smaller volume has to be magnetized or demagnetized. The installed coil rating can be correspondingly lower, which can have cost advantages and also weight advantages. This results further in short switching on and off times. Since, according to the invention, the fastening screws act on the second part of the magnet housing and the first part is therefore bore-free and hole-free with regard to fastening screws of this type, it does not have to be dimensioned in such a way that there is space for holes for fastening screws.
One particularly expedient and advantageous refinement of the spring pressure brake according to the invention can provide that that second part of the magnet housing which is connected to the pot magnet is comprised of a material which has a lower specific weight than the material of the first part of the magnet housing, that is to say of the pot magnet. Since the magnet housing is therefore comprised partially of lighter material, the overall weight of the magnet housing can be reduced correspondingly.
Due to its shape and its dimensions, the non-magnetizable second part of the magnet housing which is comprised of a lighter material than the pot magnet or the first part of the magnet housing can have a lower weight than the first part of the magnet housing. It can be assumed here that the overall volume of the material of the second part of the magnet housing is smaller than the volume of the first part or of the pot magnet, with the result that, just for this reason, the overall weight of the non-magnetizable second part of the magnet housing is considerably lower than that of the first part on account of the different specific weights. In every case, the overall weight is reduced with respect to a spring pressure brake, the magnet housing of which is comprised practically completely of magnetizable material.
Despite this production according to the invention of the magnet housing from at least two different materials, a central compression spring or individual compression springs which are arranged at a radial spacing from the longitudinal center axis of said spring pressure brake and of its magnet housing can expediently press the brake disk against the mating disk or the armature disk against the brake disk and, as a result, the brake disk against the mating disk when current is not applied to the electromagnetic coil.
The non-magnetizable material of the second part of the magnet housing can be a material which can be injection molded, in particular plastic or aluminum. The overall production is simplified as a result.
It is possible that that first part of the magnet housing which is comprised of magnetizable material and the second part of the magnet housing are connected to one another by injection molding if a material which is correspondingly capable of being injection molded forms the second part. Any possible additional fastening operations or fastening elements can therefore be avoided.
At least on the outer side or circumferential side of the first magnetizable part of the magnet housing, at least one region which differs from the contour of this outer side, in particular from a round or cylindrical contour of said outer side or a plurality of regions of this type can be provided which engages/engage or is/are embedded into the non-magnetizable material of the second part from the inside in the use position. A projection or a depression or a region of the same type which differs from a smooth contour can therefore be provided on the outside on an as a rule cylindrical pot magnet, in particular on its circumference, but also possibly on its end side, which projection or depression or region of the same type which differs from a smooth contour is enclosed by the material of the second part, with the result that the two parts are connected in a rotationally fixed and preferably positively locking manner, which results in a stronger connection than if the second part engages around a smooth outer side of the first part. This also optionally makes a longer service life possible, above all if said spring pressure brake is used in applications which are susceptible to vibrations or are loaded dynamically.
A further refinement of the invention for saving weight can provide that that second part of the magnet housing which is comprised of non-magnetizable material has at least one or more interruptions on that end side of the pot magnet which is covered or engaged over by it, on its side which faces away from the armature disk. As a result of interruptions of this type, the quantity of the material of the second part of the magnet housing can be reduced. Here, said interruptions have the further advantage that the dissipation of heat from the magnetizable part is aided.
A further possibility is provided in that the electric feed line to the electromagnetic coil runs through an end-side interruption of the second part of the magnet housing. The magnetizable first part of the magnet housing can be comprised of sintered metal. This has the advantage that recourse can be made during the production of said first part of the magnet housing to a technique which has proven itself for pot magnets.
A special holding device or a flange or a mounting of this type is expediently provided for the mating disk which interacts with the brake disk. Here, one refinement of the invention can provide that said holding device, which can be connected or is connected in the use position to the magnet housing, for the mating disk is comprised of a non-magnetizable material, in particular from a material, the specific weight of which is lower than that of steel or magnetizable sintered metal. The concept of saving weight and ruling out leakage losses as far as possible is therefore also applied to or realized with said holding device for the mating disk of the spring pressure brake.
It is possible here that the holding device for the mating disk is configured as a cover or housing part which, in its interior, contains the mating disk arranged concentrically with respect to the longitudinal center axis and is connected to the magnet housing in the use position via fastening screws and/or via the fastening screws for the spring pressure brake and is comprised of plastic or aluminum, preferably from the same material as the second part of the magnet housing. This holding device, which is preferably configured as a cover or housing, for the mating disk can optionally be fixed by way of fastening screws which are provided specially for it or optionally additionally by way of the fixing screws which are also provided for the mounting of the spring pressure brake, for example, on an engine housing.
A further refinement of the spring pressure brake according to the invention, in particular of one with a holding device for the mating disk, can provide that this holding device for the mating disk has at least one opening which runs in the axial direction at the circumference of the spring pressure brake for a projection, engaging radially therein, of the armature disk, and that the holding device also holds the armature disk in its use position as a result. Here, this opening is dimensioned to be sufficiently large in the axial direction, in order to give the armature disk the axial freedom of movement which is required for its function. As a result, the holding device for the mating disk is given an additional function, since it ensures the fixing of the armature disk in the rotational direction, with the result that no other, possibly complicated measures are necessary to make the armature disk rotationally fixed or non-rotatable.
It is expedient for a symmetrical and balanced arrangement if the holding device for the mating disk has at least two openings, lying opposite one another on the circumference of the arrangement, for two projections of the armature disk which are aligned with one another. The armature disk can therefore expediently have two regions or projections which project radially with respect to its circumference, engage in the use position into the openings of the holding device which are arranged in a matching manner thereto and lie opposite one another, and result in correspondingly balanced and symmetrical absorption of a torque which acts on the armature disk in the case of braking.
That second part of the magnet housing which is also arranged on the end side of the pot magnet and is made from non-magnetizable material can have a central opening coaxially with respect to the longitudinal center axis of the pot magnet and with respect to a central opening which penetrates it and the circular cross section or diameter of which is smaller than that of the central opening of the spring pressure brake, and that annular region of the second part which projects radially into the region or cross section of the central opening can form a supporting face for a central compression spring. It is therefore possible to provide the second part of the magnet housing in the region of the central opening of the pot magnet with an opening which is narrower than the central opening, it optionally being possible for said second part to cover the central opening of the pot magnet even completely, in order to support the central compression spring of a spring pressure brake of this type.
Above all, a combination of individual or several ones of the above-described features and measures results in a spring pressure brake, in which, as a result of the division of the magnet housing, the mass of magnetizable material can be reduced and overall the weight can also be lowered, with the result that magnetic losses, leakage fluxes or leakage losses in the region of the electromagnetic coil and of the pot magnet can be avoided as far as possible or optionally even completely. This can be assisted by the fact that the flange or the holding device for the mating disk is also comprised of a non-magnetizable material of the type, as is provided for the second part of the magnet housing. Here, at the same time, the holding device for the mating disk which serves as abutment for the brake disk can be used to grip the armature disk positively on its circumference and to make it non-rotatable as a result.
In the following text, one exemplary embodiment of the invention is described in greater detail using the drawing, in which, in a partially diagrammatic illustration:
A spring pressure brake which is denoted overall by 1 has a magnet housing 2 which is shown separately in
In
It can be seen clearly in
It can be seen, above all, using
As can be seen particularly clearly in
Here, that second part 15 of the magnet housing 2 which is connected to the pot magnet 14 is comprised of a material which has a lower specific weight than the material of the pot magnet 14. Here, said non-magnetizable second part 15 of the magnet housing 2, which second part 15 is comprised of a lighter material than the pot magnet 14, also has a lower weight overall, on account of its shape and its dimensions, than the first part or pot magnet 14. The entire arrangement or spring pressure brake 1 can therefore be of weight-saving construction. For example, the non-magnetizable material of the second part 15 of the magnet housing 2 can be a material which can be injection molded, for example plastic or aluminum. As a result, it is possible to connect the first part 14 and the second part 15 of the magnet housing 2 to one another by injection molding.
It is indicated in
The result of
It can be seen, above all, in
The openings 18 are open in the axial direction for mounting which is as simple as possible and additionally rotationally fixed connection to the magnet housing 2, with the result that the holding device 8 can be plugged onto the magnet housing 2 and mating projections 20 provided thereon.
Moreover, it is seen in
The spring pressure brake 1 has a magnet housing 2 with an annular space or an annular groove 3 for receiving an electromagnetic coil 4. The magnet housing 2 is formed of two parts, the first part 14 of which has the annular space 3 and is comprised of magnetizable sintered metal, that is to say forms a pot magnet. The second part 15 of the magnet housing 2 encloses a part region of the first part 14 and also its end side 14a and is comprised of a non-magnetizable material, the specific weight of which is lower than that of the material of the first part or pot magnet 14. Magnetic losses can therefore be reduced or avoided and weight can be saved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202012000897.8 | Jan 2012 | DE | national |
