DE19737485C1 - Electromagnetically-operated brake - Google Patents

Abstract

The brake has at least one electromagnetic coil (2) wound on a coil former (11) receiving a spring mechanism (3) acting on an axially displaced armature disc (4) and a rotary brake disc (5) with a brake flange (10) on the side facing the coil former. The spring mechanism has a number of different size or differently spaced spring elements providing an asymmetric force for the armature disc. An Independent claim for a multiple braking unit with at least 2 electromagnetically-operated brakes is also included.

Description

The invention relates to an electromagnetically actuated Brake with at least one electromagnetic coil and one Spring arrangement receiving bobbin, one - on one Axis of rotation related - axially displaceably mounted anchor plate be loaded by the force of the spring assembly, egg ner rotatably arranged brake disc and one on the Coil side away from the brake disc Brake flange, as well as a multiple brake unit with at least two such electromagnetically actuated brakes.

From DE 33 38 289 C2 is a spring-operated and Electromagnetically ventilated friction brake known in which one Electromagnets an armature movable in the axial direction disc is assigned. This armature disk consists of several ren individual annular dividing disks, which together with Using several rotationally symmetrical around an associated ar beitswelle arranged compression springs against a brake disc be pressed. The brake disc has corresponding brake pads and is with the help of a hub to which it has a Gearing is fixed, rotatably ver with the working shaft bound. The friction brake is released via a shutter  ten of the electromagnet, which made the different degrees led ring-shaped dividing discs differently against the Force of the compression springs attracts, so that a reduced Impact noise of such a brake compared to a brake with one-piece armature plate.

DE 24 04 473 A1 discloses an electromagnetically ventilable Spring-applied brake for an elevator engine in which the anchor disc from several, in the axial direction by the size of the Armature stroke is independent of moving parts. This independently movable parts is a ge common release magnet as well as a set of compression springs assigned.

From DE 295 10 828 U1 is an electromagnetically operated Friction safety brake known, one on both sides individual, centrally arranged solenoid coil one each core disk and a brake disk as well as the armature disk Associated spring arrangement pressing against the brake disc are.

DE 27 30 168 A1 discloses an electromagnetically ventilable Spring pressure brake intended for two-stage braking, where a two-piece armature plate from a radially inner and a radially outer part, both the ra dial inner and the radially outer part each own Spring arrangements are assigned.

Another electromagnetically ventilated spring pressure brake is known from DE 34 24 595 A1. The anchor plate of this Fe the pressure brake is divided into several segment-like sections structure that is independently spring-loaded and axial are movable, and which lie in a common plane. The anchor plate segments are several independently on and switchable electromagnets assigned in a ge common level of action and each individually or in groups can act wisely on the segments.  

DE-OS 15 75 989 relates to an electromagnetic brake, the a central brake disc as well as on both sides of the brake disc each has an electromagnet. Every elec A brake shoe is assigned to the tromagneten the brake disc works. The brake thus makes a double brake unit.

The object of the invention is to operate an electromagnetically bare brake of the type mentioned and a multiple Brake unit with at least two such electromagnets table-operated brakes to create, if possible simple construction and small installation space a reduced switching exhibit noise.

This object is achieved in that the Spring arrangement of different dimensions and / or ver divides arranged spring elements, which on the anchor disk asymmetrically distributed force with respect to the axis of rotation exert moments. By the solution according to the invention Proverb 1 is the armature plate continuously with an asym metrically distributed load, which leads to the fact that the armature plate during an actuation process resulting from the sum of the magnetic and spring forces Force deformed elastically on bending. This results in a uneven and thus noise-reduced striking the Armature disk against the coil body or the brake disk.

Through the various inventions described below Configurations according to the invention result in a compact structure Built brake unit, which has a reduced switching noise and safe and uncomplicated handling guaranteed.

The features of claim 2 result in a cushion tes and dampened stop of the brake disc on the friction disc or the brake flange, which means that if there is an incident Armature disk a noise reduction is achieved.  Due to the features of claim 3 with simple torsional vibrations of the brake disc and thus also the Ar beitswelle heavily damped in the braked state and additional Impact noises between the armature disk and the friction element minimized.

Due to the features of claim 6, the actuator is noise of the multi-part armature plate both at Incident and sustainably dampened when ventilating.

In a further embodiment of the invention according to claim 4 the vine element as an axially penetrating the brake disc Friction block executed, the two parallel, perpendicular to the rotation has axis-oriented friction surfaces. This ensures security provides that the friction element on the brake easily and safely disc is mounted and optimal for vibration damping is settable.

In a further embodiment of the invention according to claim 5 the friction element two parallel, perpendicular to the axis of rotation ori ent friction surfaces with different distances to the each adjacent end faces of the brake disc. In order to there is sufficient wear adjustment for the ent speaking brake available.

Through an advantageous development of the invention with the Features of claim 7 will be particularly quiet Actuated brake created, the armature plate in part with an optimal thickness and mass ratio is divided, with the additional coatings of the thinner Dividing discs with layers of non-magnetic and / or ela resilient material further noise reduction effects achieve. This results in particular with a coating a weakening of the non-magnetic material magnetic flux between the individual dividing disks. Especially when using a coating made of ela  soft material results in a low-noise Cushioning of the abutting dividing disks.

For the multiple brake unit, the task is performed by Features of claim 8 solved. This results in a simple and compact brake unit with special simple means on an existing work wave can be set and adjusted to reduce noise.

Due to the features of claim 10, a particularly ge low-noise switchable brake unit achieved because the anchor discs do not move at the same time, but move at different times are bar, which means that the noise level is reduced accordingly is lowered.

Further advantages and features of the invention result from the subclaims. The following is a preferred embodiment Example of the invention described and based on a Drawing shown.

The only drawing, Fig. 1, shows an Ausfüh approximate shape of a double brake gates according to the invention in an axial cross section.

A hoist in the form of a brochure for lifting and lowering loads has an electric motor, not shown, which drives a cable, not shown, via a working shaft 14 , to which corresponding loads are fastened by means of suspension means. With such a brochure, people can also be transported. On the working shaft 14 , a double brake unit 1 according to the invention is placed and screwed ver via a mounting plate 10 to a stationary housing 15 , the mounting plate 10 serving in the manner described below as a brake flange 10 for a brake disk 5 for the spring-loaded brake 1 a.

The double brake 1 consists of two electromagnetically actuated spring pressure brakes 1 a and 1 b, which are largely identical in structure, which is why the following detailed description of the first spring pressure brake 1 a is equally valid for the second spring pressure brake 1 b. For identical parts of both spring pressure brakes 1 a, 1 b apply the same reference characters, so that the reference numerals can be transferred to both spring pressure brakes. Both Federdruckbrem sen 1 a, 1 b are structurally connected to each other in the manner described in detail below and arranged coaxially to an axis of rotation of the working shaft 14 .

The double design of the double brake unit 1 ensures reliability, since even if one brake fails, a reliable braking operation is achieved by the other brake.

The spring-loaded brake 1 a has a coil body 11 , in which not only an annular electromagnetic coil 2 , but also a spring arrangement in the form of a plurality of springs arranged in the same part around the working shaft 14 are arranged compression springs 3 . Between the bobbin 11 and a rotatably connected via a stub shaft 13 to the working shaft 14 brake disc 5 is a three-part armature plate 4 is arranged in the axial direction, which is loaded by the prestressed helical compression springs in the axial direction with forces. The stub shaft 13 is fixed on the working shaft 14 by means of a tongue and groove connection. On the side of the brake disk 5 opposite the armature disk 4 , the brake flange 10 is assigned a friction disk 6 , which is fastened together with the fastening screws for fixing the brake flange 10 to the housing 15 on the end face of the brake flange 10 .

The coil body 11 is screwed with respect to its axial distance to the brake flange 10 such that an adequate air gap for the armature disk 4 between the spool body 11 and several, the brake disc 5 penetrating brake pads 7 is available. The brake pads 7 mentioned have a uniform geometric shape and are arranged in receptacles arranged symmetrically about the axis of rotation in the brake disc 5 . They protrude the brake disc 5 on both sides in the axial direction, as can be seen in FIG. 1 bar. As a result, the perpendicular to the axis of rotation of the Ar beitswelle 14 oriented end faces of the brake pads 7 are the wearable friction surfaces of the brake, which are in frictional contact with the brake disk 5 facing the end faces of the friction disk 6 and the armature disk 4 in contact. The dimensions by which the brake pads 7 protrude from the brake disc 5 in the axial direction are in principle freely selectable and depend in particular on the degree of wear of the end faces of the brake pads 7 .

The two identical spring-applied brakes 1 a and 1 b are combined to form an extremely compact double brake unit in that one of the spring-loaded brakes 1 b facing the end face of the coil body 11 of the spring-loaded brake 1 a is designed as a brake flange, which is identical to the brake flange 10 and has a plate-shaped friction disc 6 is assigned. The coil body 12 of the second brake 1 b is mounted via corresponding screw connections in the axial direction adjustable on the coil body 11 of the first brake.

The function of such a double brake is known per se and is therefore only briefly outlined as follows. In the current-free state of the electromagnetic coils 2 , each armature disk 4 is pressed by the forces of the helical compression springs 3 in the axial direction against the brake pads 7 , which is thereby clamped between the armature disk 4 on the one hand and the friction disk 6 on the other hand, whereby a rotation of the working shaft 14 is prevented with sufficient spring force. The double brake 1 can be released in that either the electromagnetic coils 2 are struck appropriately, or that with the aid of a hand lever, the core disks 4 are moved against the forces of the screw pressure springs 3 by the respective brake disks 6 manually. The hand lever for manual release is such arranged on the anchor plate 4 so that it acts in the areas of Größ th spring forces on the anchor disc 4 in order to ensure a uniform ventilation. As a result, the friction circuit between armature disks 4 , brake pads 7 and friction disks 6 is canceled, whereby the rotation of the working shaft 14 together with brake disks 5 and stub shaft 13 is released. Switching off or reducing the coil current then causes the armature disks to drop again and the braking of the working shaft again.

When invented using the exemplary embodiment The following considerations came into play. At Such switching operations result in a conflict of objectives between the safe and quick effectiveness of the brake on the one hand and the noise emissions from moving components on the other hand. Noise emissions can basically be con structurally reduced by the fact that the speed of moving parts is kept low. This can happen by happening that the air gaps in the brake are so small be kept as possible, taking shape and positional tolerances as well as a desired wear reserve a certain min require minimum value. The accelerations and thus the Ge speed of the armature washers can be magnetic field that slowly builds up and breaks down is kept low be, with the required switching time of the brake lower limit is given. In terms of noise emissions are steep or progressive spring characteristics lines are particularly advantageous because in this way the Spring forces come closest to the magnetic force; to get out however a spring-loaded disc brake con over the wear To maintain constant braking torque are helical compression springs with a characteristic curve that is as flat as possible. By absolute spring forces as small as possible would be low loading accelerations of the armature plates result in what with regard the noise would be cheap, but requires that desired braking torque in a small installation space great spring force. To reduce the momentum of the moving Armature washers with a view to reducing noise  emissions is a reduction of unsprung, moving Masses desirable, with the minimum mass of an anchor slice through the volume required for the magnetic flux is limited for a given ferromagnetic material.

According to the invention, the following con structural measures for effective noise reduction at the same time high effectiveness, operational safety and low Installation space of the double brake already explained.

The helical compression springs 3 of the brake 1 a are arranged unevenly or asymmetrically on a circular line around the working shaft 14 . This means that in a certain sector ei ne closer arrangement of the helical compression springs 3 is selected, so that the armature disk in this area is subjected to an average higher load than in other areas. This causes in particular when lifting the armature plate that due to the uniformly distributed magnetic field with unevenly distributed spring forces, the armature plate is tightened unevenly. Through a positive feedback effect, he also increases the magnetic flux at the point of the lowest ring spring forces, which meets the point from the lowest position between armature plate and solenoid coils, faster than at the point of higher spring forces, so that the armature plate is not flat and thus strikes the bobbin 11 with reduced noise. Such an uneven spring arrangement can have one or more points with increased spring force, the function of such an arrangement being favored by a correspondingly deformable core disk. In this context, it proves to be particularly advantageous that the armature disk 4 is divided up in the axial direction into a plurality of partial disks 4 a, 4 b, 4 c, of which at least the first partial disk 4 a arranged on the side of the coil former 11 is relatively thin out and is able to deform elastically.

The armature disk 4 in three dividing disks 4 a, 4 b, 4 c, also serves to reduce noise. The Dickenver ratio of the part disks 4 a, 4 b, 4 c is in the axial direction Rich starting from the part facing the coil body 4 a 1: 1: 3, as was already proposed in the patent DE 33 38 289 C2. Furthermore, the two thin armature disks 4 a and 4 b with ge serving as a coating noise-absorbing films 8 , 9 are glued. The perpendicular to the axis of rotation of the working shaft 14 and facing the spool by 11 end face of the index plate 4 a, and the two plane-parallel end faces of the middle part disc 4 b are each covered with an elastically flexible film 8 , 9 made of non-magnetic material, a dual function exerting: Firstly, the magnetic flux between the sheaves by a quasi "artificial air gap" is inhibited, whereby, when activated, the solenoid coil 2 and thus the brake is released the magneti-specific flow in the two partial disks 4 b and 4 c through these layers are arranged on the side facing away from the bobbin, is reduced ver. This results in a faster breakdown of the magnetic field and thus a shorter incidence time. On the other hand, the resilient layers dampen the opening of the indexing discs 4 a to 4 c against each other and against the coil former, with the effect of the forces of the helical compression springs on the component discs 4 a, 4 b, 4 c also being cushioned.

As a further, with a view to reducing the noise missions of the double brake according to the invention extremely effec tive measure, the use of brake pads 7 is hen, which, as shown in FIG. 1, enforce the brake discs 5 and protrude on both sides in the axial direction. As already mentioned, the brake pads 7 are inserted in receptacles of the brake discs 5 , in which they are held in a form-fitting manner in the circumferential direction and in the radial direction. The brake pads 7 , which serve as friction pads, have the advantages over friction linings glued to the brake disk that, due to their greater thickness, they dampen both impacts on the armature disk 4 and torsional vibrations of the working shaft considerably better. In addition, they can be reliably inserted into the receiving pockets with simple means. In the illustrated embodiment, the friction blocks are axially fixed in the receptacles by means of press fits.

As a further noise reduction measure, it is provided that the friction disk 6 is implemented on each brake flange with a low setting. This results in an elastic flexibility of the friction disc, which thus counteracts the brake pads 7 with a certain spring force when the brake is applied. This also results in an air gap between part of the friction disk 6 and the brake flange 10 . The air to be displaced from this, in turn, dampens the switching noise of the brake.

As a further measure to minimize noise when switching th the double brake 1 is provided to switch the currents of the electromagnetic coils 2 and thus their magnetic fields at different times with the help of an electronic control. Since it is caused that the armature plates 4 also occur in a time-shifted manner and are optionally vented. For this purpose, it is proposed in particular to switch the electromagnetic coil 2 of the first brake 1 a on the DC side and that of the second brake 1 b on the AC side. The formwork must be set so that even in the worst case the permissible drop of the lifting load is not exceeded. In the illustrated double brake 1 , this switching function is achieved by means of control electronics by means of corresponding electronic components.

As a further measure, the use of a one-piece stub shaft 13 with two ring flanges 13 a and 13 b is provided, the axial distance is smaller than the axial distance of the brake discs 5 of the two brakes 1 a and 1 b. According to the invention is an axially displaceable arrangement of the brake discs 5 provided on the stub shaft 13 wherein a is present in FIG. 1 is not to be taken Direction distance between the brake discs ben 5 and the respective annular flange 13 a and 13 b, so that a flexible adjustment the bobbin 11 of the first brake 1 a relative to the mounting plate 10 on the one hand and the bobbin 12 of the second brake 1 b relative to the bobbin 11 of the first brake 1 a is made possible. The axial displaceability of the brake discs 5 and the simultaneous rotationally fixed entrainment with the stub shaft 13 is achieved by corresponding peripheral teeth on the circumference of the stub shaft 13 on the one hand and on the inner contours of the brake discs on the other hand. Such an adjustment is particularly necessary when the air gaps have increased due to wear on the brake pads 7 , so that the spring forces have dropped to a lower limit value when the brake is activated and / or the actuation path of the armature disks has increased so much that the Schlagge noise of the armature plate 4 is excessively increased. The proposed arrangement, through which the manufac turing and assembly costs are considerably reduced, ensures a large wear position that can be carried out with simple means, by means of which the switching noise of the brake can be kept low.

Overall, this results in a double brake, the air and incident noise far below a value of 60 dB (A) lie, which can also be almost excluded that the switching noise of the brake even under unfavorable installation conditions, especially with corresponding resonances, is not amplified to over 60 dB (A). So you can go high Requirements for the noise emissions of such Brake, as they are set in theater construction, just who the.

Claims (11)

1. Electromagnetically actuated brake with

• 1. an at least one electromagnetic coil ( 2 ) and a spring arrangement ( 3 ) accommodating coil former ( 11 ),
• 2. one - based on an axis of rotation - axially displaceably mounted armature plate ( 4 ), which is loaded by the force of the Fe deranordnung ( 3 ),
• 3. a rotatably arranged brake disc ( 5 ) and
• 4. a brake flange ( 10 ) arranged on the side of the brake disk facing away from the coil former ( 11 ),

characterized in that the spring arrangement ( 3 ) has differently dimensioned and / or distributed spring elements which exert force moments distributed asymmetrically with respect to the axis of rotation on the armature disk ( 4 ). 2. Electromagnetically actuated brake according to claim 1, characterized in that the brake flange ( 10 ) comprises an axially resilient, in particular plate-shaped, friction disc ( 6 ). 3. Electromagnetically actuated brake according to one of claims 1 or 2, characterized in that the brake disc be ( 5 ) has at least one axially on both sides of the brake disc protruding friction element ( 7 ). 4. Electromagnetically actuated brake according to claim 3, characterized in that the friction element ( 7 ) is designed as a brake disc ( 5 ) axially penetrating friction block, which has two parallel, perpendicular to the axis of rotation oriented friction surfaces. 5. Electromagnetically actuated brake according to one of claims 3 or 4, characterized in that the friction element ( 7 ) has two parallel, perpendicular to the axis of rotation oriented friction surfaces at different distances from the respective end faces of the brake disc ( 5 ). 6. Electromagnetically actuated brake according to one of claims 1 to 5, characterized in that the armature disk ( 4 ) is divided up into at least two axially displaced partial disks, with at least one partial disk in the area we at least one end face a coating of non-magnetic and / or resilient material. 7. Electromagnetically actuated brake according to claim 6, characterized in that the armature disk ( 4 ) is divided into three axially offset partial disks ( 4 a, 4 b, 4 c), de ren thickness ratio in the axial direction starting from the side facing the coil body 1st : 1: 3, the end face of the first partial disk ( 4 a) arranged on the side of the coil former and both end faces of the middle partial disk ( 4 b) facing the coil former each having a coating of non-magnetic and / or elastically flexible material exhibit. 8. Multiple brake unit with at least two electromagnetic table actuated brakes ( 1 a, 1 b), which are designed according to one of claims 1 to 7, characterized in that the coil body ( 11 ) of a first brake ( 1 a) as a brake flange adjacent second brake ( 1 b) is designed. 9. Multiple brake unit according to claim 8, characterized in that the brake discs ( 5 ) of the at least two electromagnetically actuated brakes ( 1 a, 1 b) are mounted on a common, one-piece stub shaft ( 13 ). 10. Multiple brake unit according to one of claims 8 or 9, characterized in that control means are provided, by means of which the armature disks ( 4 ) of the at least two electromagnetically actuated brakes can be moved with respect to one another with a time offset. 11. Multiple brake unit according to claim 10, characterized in that the control means have electronic components, by means of which the staggered actuation of the armature disks ( 4 ) can be achieved.