Braking device and electric motor

Abstract

Braking device (1) comprising at least a first magnet device (2.1), at least a second magnet device (2.2), at least one braking element (3), and at least one magnetically conductive rotor (4), wherein one of the two magnet devices (2.1, 2.2) comprises at least one electromagnet (5), wherein the other of the two magnet devices (2.2, 2.1) comprises at least one permanent magnet (6), wherein the braking element (3) is movable at least between a braking position (BP) contacting the rotor (4) and a release position (FP) spaced apart from the rotor (4), characterized in that the first magnet device (2.1) is held stationary and rotationally fixed, that the second magnet device (2.2) is connected to the brake element (3) such that the brake element (3) is moved into the braking position (BP) by the action of the permanent magnet (6) when the electromagnet (5) is switched off, and that the brake element (3) is moved into the release position (FP) when the electromagnet (5) is switched on.

Description

[0001] The invention relates to a braking device, in particular for an electric motor, and an electric motor with such a braking device. The braking device comprises at least one first magnetic device, at least one second magnetic device, at least one braking element, and at least one magnetically conductive rotor. One of the two magnetic devices comprises at least one electromagnet. The other of the two magnetic devices comprises at least one permanent magnet. The braking element is movable at least between a braking position in contact with the rotor and a release position spaced apart from the rotor.

[0002] In the prior art, braking devices are known comprising a first magnetic device, a second magnetic device, a braking element, and a magnetically conductive rotor. One of the two magnetic devices has at least one electromagnet, while the other of the two magnetic devices has at least one permanent magnet. The braking element is movable between a braking position in contact with the rotor and a release position spaced apart from the rotor.

[0003] Such braking devices, as part of an electric motor, serve to brake the motor. In the prior art, for example, braking devices designed as electromagnetic holding brakes are known. Such holding brakes serve to hold the rotor of the electric motor in a specific position and are not suitable for braking the rotor. Using the braking device, corresponding automation applications can be implemented reliably, thus enabling a so-called "fail-safe" function. Furthermore, the braking device can relieve the electric motor when the rotor is statically "held" by the electric motor, if the automation application requires a stationary rotor. The braking device, in particular the holding brake, is closed when de-energized and then exerts its braking or holding effect.When energized, the braking device, in particular the holding brake, is open, allowing the rotor of the braking device, especially the rotor of the electric motor, to rotate. In other words, the braking device opens electromagnetically. Braking devices designed as so-called permanent magnet brakes are known and available on the market.

[0004] In known permanent magnet brakes, a first magnetic device with at least one permanent magnet, a second magnetic device with at least one electromagnet, a brake element comprising an iron armature, and a rotor are arranged side by side in that order in the axial direction. The brake element and the rotor are connected by a spring pre-tensioned towards the rotor. The first and second magnetic devices are fixed in position and prevented from rotating. When the electromagnet is de-energized, the brake element is moved away from the rotor into a braking position by the magnetic field of the permanent magnet. A frictional force is generated between the brake element and a braking counter-element by the magnetic field of the permanent magnet.The release of the brake element from the brake counter-element is achieved by energizing the electromagnet, which then generates an electromagnetic field directed against the magnetic field of the permanent magnet, so that the brake element is moved towards the rotor into a release position by the spring force of the spring.

[0005] For high braking torques, such permanent magnet brakes require disadvantageously strong magnetic fields from the permanent magnet. Furthermore, the iron armature must be massive, resulting in a high moment of inertia for the braking element, particularly the corresponding armature disk. This high moment of inertia is especially problematic because the braking element rotates with the rotor in its release position. Additionally, an air gap between the braking element in its release position and the counter-braking element must be incorporated into the design.

[0006] The invention is based on the objective of reducing the disadvantages of the prior art and, in particular, improving the effectiveness of the electrical magnetic circuit of the braking device.

[0007] The object of the invention is achieved by the features of the characterizing part of claim 1, namely in that the first magnetic device is held in a fixed position and is rotationally fixed, that the second magnetic device is connected to the braking element, that the braking element is moved into the braking position by the action of the permanent magnet when the electromagnet is switched off, and that the braking element is moved into the release position when the electromagnet is switched on.

[0008] The invention provides a highly efficient electromagnetic circuit when the braking element is in the release position and the braking device is thus open. Losses due to saturation of the braking element can be minimized. Consequently, the power consumption of the electromagnet when energized can be reduced, and heat generation by the electromagnet is advantageously minimized. With the permanent magnet in the braking position, a high axial force can be generated between the braking element and the rotor, resulting in a correspondingly high braking force or holding force of the braking device. Furthermore, the described arrangement of the elements of the braking device, in particular the first and second magnets, allows for a reduction in the axial length of the braking device.Because the first magnetic device is held in a fixed position and is rotationally fixed, and because the second magnetic device is connected to the non-rotating, but only axially movable, brake element, the rotatable mass of the brake device is minimized, which has a beneficial effect on the dynamics of the brake device.

[0009] When the brake element is in the braking position, it is held in this position by the force of the permanent magnet when the electromagnet is switched off. When the brake element is in the release position, it is held in this position by the electromagnet when it is switched on, specifically by the force exerted by the electromagnet.

[0010] Preferably, the brake element is designed as a brake disc. Such a brake disc has a thickness and an outer circumference, wherein the values ​​of the outer circumference diameter are significantly larger than the thickness values, with the diameters being perpendicular to the thickness.

[0011] Particularly when the brake element is designed as a brake disc, a flat design of the brake device can be achieved, i.e., a small expansion of the brake device in the thickness direction or in a direction along the rotation axis of the rotor. Furthermore, the invention prevents excessive heating.

[0012] In an advantageous embodiment of the invention, the braking element is movable parallel, i.e. axially, to an axis of rotation of the rotor, and the braking element contacts an end face of the rotor in its braking position.

[0013] The axial guidance of the braking device advantageously reduces its outer circumference, which then corresponds in particular to the outer circumference of the rotor. Large contact surfaces with the braking element are accessible via the rotor's end face, which has a beneficial effect on the achievable braking and holding forces.

[0014] In an advantageous embodiment of the invention, the second magnetic device connected to the braking element comprises at least one permanent magnet, wherein the permanent magnet is arranged on the braking element such that, when the electromagnet is switched off, the braking element is moved into the braking position by the magnetic force acting between the permanent magnet and the rotor. When the electromagnet is switched on, the braking element is moved into the release position by the magnetic force acting between the braking element and / or the permanent magnet on the one hand and the electromagnet on the other.

[0015] Thus, the electromagnet is held in a fixed position and prevented from rotating, resulting in a simple power supply for the electromagnet. In particular, no current needs to be transferred between moving components.

[0016] A further advantage of the invention is that the power consumption and heat generation of the braking device can be kept particularly low. This is achieved by requiring only a very brief high release power to disengage the brake, while holding the brake element in the release position requires only a very low holding power due to the small or non-existent air gap between the electromagnet and the braking element. This minimizes the average power consumption of the electromagnet during operation of the braking device and reliably prevents excessive heating.

[0017] In an advantageous embodiment of the invention, the braking element is supported against rotation relative to the first magnet device by the first magnet device and / or a machine frame. The braking or holding forces for the rotor can be generated via this support and / or transmitted to the first magnet device and / or the machine frame. The first magnet device and / or the machine frame are designed such that they can absorb these braking or holding forces without moving themselves and, for this purpose, have, for example, a correspondingly large mass or are themselves connected to a component of correspondingly large mass. The braking element is supported against rotation, in particular via the end face of the braking element facing away from the rotor, on the first magnet device. The braking element is also supported against rotation, in particular via an outer circumference of the braking element, on the machine frame.

[0018] In an advantageous embodiment of the invention, the brake element is connected to the first magnetic device by means of a spring element, in particular a spring disc. The spring element is elastically deformable to allow axial movement of the brake element between the braking position and the release position.

[0019] The spring element is specifically designed as a bending spring and / or has a corresponding bending range. The spring element is under tension, in particular, when the brake element is in the braking position. The spring element is relaxed, in particular, when the brake element is in the release position, so that the forces exerted by the electromagnet on the brake element to hold it in the release position are not adversely increased by the spring element. Furthermore, in this way, the force exerted by the spring element can assist the movement of the brake element from the braking position to the release position.

[0020] In an advantageous embodiment of the invention, the spring element, in particular the spring disc, is designed to transmit, during operation of the braking device, the braking torques that can be formed between the brake element positioned in the braking position and the rotor, in particular between the brake element and the magnet device and / or a machine frame.

[0021] This expands the function of the spring element, allowing for a reduction in the number of components in the brake system. A reduction in the number of components also advantageously leads to a reduction in the number of joints required during the manufacturing and assembly of the brake system.

[0022] In an advantageous embodiment of the invention, the spring element, in particular the spring disc, is connected to the first magnet device along a first circular path, and the spring disc is connected to the brake element along a second circular path. Preferably, the diameter of the first circular path differs from the diameter of the second circular path.

[0023] Between the first circular path and the second circular path of the spring element, in particular the spring disc, at least one bending region of the spring element is preferably formed, wherein the spring action is realized in particular by means of this bending region. The spring element is designed to deform elastically, in particular in the bending region.

[0024] In an advantageous embodiment of the brake device, the spring element, in particular the spring disc, has at least one axially extending recess that forms at least partially along a circular path in a circumferentially extending section of the spring element, in particular the spring disc. The spring element is preferably formed in one piece. This further reduces the number of components in the brake device. The spring element preferably comprises a metal, particularly preferably spring steel. The spring element is particularly preferably formed as a stamped part. The spring element preferably has a constant thickness, wherein the extension of the spring element in the direction of the axis of rotation corresponds to this thickness when the spring element is in its undeformed state and the brake element is particularly in the release position.

[0025] In an advantageous embodiment of the invention, the brake element is connected to the first magnetic device and / or a machine frame by means of a positive locking connection that allows movement of the brake element in the axial direction, in particular preventing rotation.

[0026] The positive-locking connection is achieved, for example, with a groove and a projection engaging in this groove. Such a projection is formed, for example, on the brake element, and the corresponding groove is then formed on the first magnet device and / or the machine frame, whereby a reciprocal arrangement is also provided. Through such a positive-locking connection, braking or holding forces for the rotor can be generated in addition to the spring element and / or transmitted from the rotor via the brake element to the first magnet device and / or the machine frame.

[0027] In an advantageous embodiment of the invention, the rotor is rotatably mounted or can be mounted relative to a machine frame by means of a rotor bearing. Preferably, the rotor is fixed axially relative to the machine frame by means of the rotor bearing.

[0028] Thus, the rotor bearing absorbs the forces transmitted axially from the brake element to the rotor, which occur particularly when the brake element, in its braking position, contacts an end face of the rotor. In an advantageous embodiment of the invention, the first magnet device, the brake element, and the rotor each have a cylindrical outer circumference. In particular, the diameters of the first magnet device, the brake element, and the rotor have the same values. This further increases the compactness of the entire braking device.

[0029] In an advantageous embodiment of the invention, several permanent magnets are arranged on the brake element, particularly along concentric circular paths. The permanent magnets are preferably distributed over the brake element. In particular, the permanent magnets have a height that is less than the thickness of the brake element. Such a multi-pole magnet arrangement allows the axial forces acting between the brake element and the rotor to be further increased. The permanent magnets themselves can be manufactured with a simple geometric shape, making their production particularly economical. In particular, standardized permanent magnets can be used. Due to the preferred arrangement of the permanent magnets along concentric circular paths, the magnetic fields of the individual permanent magnets superimpose to form an overall magnetic field that is advantageous with respect to the generated axial force.

[0030] In an advantageous embodiment of the invention, the electromagnet comprises a coil with a thin wire, e.g., with a wire thickness of, for example, 0.05 mm to 0.15 mm, and in particular 0.08 mm to 0.12 mm. Due to the high release power required only for very short periods, a very thin wire can be used for the coil without the braking device heating up unnecessarily during holding operation. This allows for a particularly compact and short design of the electromagnet coil, which contributes to a low overall height of the braking device.

[0031] In an advantageous embodiment of the invention, the permanent magnets are identical in construction and / or cuboid in shape. Using identical permanent magnets reduces the overall manufacturing costs. Cuboid-shaped permanent magnets further simplify their production.

[0032] In an advantageous embodiment of the invention, the contact surfaces between the brake element and the rotor are designed as steel surfaces and / or at least one of the contact surfaces has a friction-enhancing layer or coating.

[0033] Contact surfaces made of steel are particularly cost-effective to produce, since the same material can then be used for the contact surfaces as for the brake element and the rotor, which are preferably also made of steel. Friction-enhancing layers or coatings must be produced in at least one additional step, but result in higher braking or holding forces that can be transmitted between the brake element and the rotor.

[0034] In an advantageous embodiment of the invention, the rotor has at least one attachment element, and a contact surface for the braking element is formed on the attachment element. Such an attachment element preferably comprises a friction-enhancing material. At a minimum, the attachment element is designed such that the application and / or creation of a friction-enhancing layer or coating is simplified.

[0035] In an advantageous embodiment of the invention, the braking device is designed to be suitable for hollow shafts. This suitability is achieved by providing the first magnet assembly, the braking element, and the rotor each with a central opening through which a shaft or other components can be passed. The spring element is preferably also ring-shaped and has a corresponding central opening. The permanent magnets are arranged on the braking element, in particular along mutually concentric circular paths around the central opening, so that the central area remains unobstructed. The electromagnet is preferably designed as a ring coil surrounding a central core area of ​​the first magnet assembly, this central core area also potentially having a through-opening.This arrangement makes it possible to implement the entire brake device as a hollow shaft design, which is particularly advantageous for external rotor motors where the rotor surrounds the stator and a central passage for cables, shafts or other components is required.

[0036] According to a further embodiment of the braking device, it comprises at least one control electronics unit, wherein the control electronics are configured to operate the electromagnet with at least two different electrical power levels, in particular with a first power level and a second power level, the first power level being greater than the second power level. The first, higher electrical power level is preferably used to move the braking element into the release position, and the second, lower power level is used to hold the release position. Preferably, operation with the first power level is carried out for at least one activation period, and operation with the second power level is carried out for at least one holding period.

[0037] The different power levels are preferably achieved using pulse-width modulation (PWM). For example, a constantly high supply voltage is applied over a certain period to transition to the enable position, and a pulse-width modulated supply voltage with a suitably selected period is applied to maintain the enable position, resulting in a lower effective supply voltage. Alternatively, the control electronics can achieve the different power levels by directly varying the current or voltage.

[0038] The control electronics can be designed as a separate electronic module or integrated as a function, for example, in a motor controller. The varying power levels are due to the air gap between the electromagnet and the brake element, as well as the air gap between the permanent magnet and the rotor, and the resulting forces. According to the invention, it has been found that to release the brake, the electromagnet must overcome the high magnetic force of the permanent magnets with a small air gap across a large air gap, which is why a high power is required briefly. To hold the release position, the electromagnet only needs to maintain the low magnetic force of the permanent magnets across a large air gap from the brake element to the rotor, and across a small or non-existent air gap from the electromagnet to the brake element, which is why only a low power is required.

[0039] This active control via pulse-width modulation allows for a significant reduction in the power consumption and heat generation of the braking device. The very high release power required for only a very short time, combined with the very low holding power of the electromagnet due to the small or non-existent air gap between the electromagnet and the braking element, enables particularly efficient operation.

[0040] The object of the invention is also achieved by the features of claim 16, namely by an electric motor comprising at least one previously described braking device, wherein the rotor of the braking device is part of a rotor of the motor, so that the motor can be braked with the braking device.

[0041] The braking device described above allows for a particularly compact design of the entire electric motor. Furthermore, automation using such an electric motor is more flexible and precise. Because the first magnetic device is fixed in position and rotationally rigid, and because the second magnetic device is connected to the braking element, which is only axially movable but not rotatable, the mass of the braking device that must be accelerated by the electric motor can be minimized. The braking device described above can advantageously be used with existing electric motors, so that no structural modifications to these existing motors are necessary.

[0042] Preferably, the electric motor is designed as an external rotor or a high-pole internal rotor. The braking device according to the invention has a particularly flat design, especially suitable for hollow shafts, which is advantageously suited for flat or short drives with large end faces of the motor rotor. The flat design of the braking device is achieved in particular by designing the braking element as a brake disc, wherein the brake disc has a thickness and an outer circumference, where the values ​​of the outer circumference are significantly larger than the values ​​of the thickness.

[0043] In particular, the arrangement of the flat, compact permanent magnets on the brake disc, along with the short and compact coil of the electromagnet, results in a small overall dimension for the braking device along the rotor's axis of rotation. The hollow-shaft-compatible design allows a shaft or other components to pass through a central opening in the braking device, which is especially advantageous for external rotor motors where the rotor surrounds the stator. The braking device according to the invention also offers advantages for high-pole internal rotor motors with correspondingly large rotor diameters, as the large end faces of the rotor provide large contact areas with the braking element, which has a beneficial effect on the achievable braking or holding forces.The described arrangement of the elements of the braking device, in particular the first and second magnet devices, allows the length of the braking device in the axial direction to be reduced, thereby minimizing the overall length of the electric motor including the braking device.

[0044] Further advantageous embodiments of the invention will become apparent from the following description of the figures and the dependent subclaims.

[0045] They show: Fig. 1 schematically a first embodiment of a braking device as part of an electric motor in a longitudinal section, Fig. 2 schematically a second embodiment of the braking device in a longitudinal section, Fig. 3 schematically a third embodiment of the braking device with the braking element in a braking position in a longitudinal section, Fig. 4 schematically a voltage curve for an electromagnet of the third embodiment of the braking device for a change from the braking position to a release position, and Fig. 5 schematically and separately a spring element for arrangement in the brake device according to the invention according to one of its embodiments in a side view.

[0046] In the various figures of the drawing, identical parts are always labelled with the same reference symbols.

[0047] The following description claims that the invention is not limited to the exemplary embodiments and not to all or several features of the described combinations of features; rather, each individual partial feature of the exemplary embodiment(s) is also significant for the subject matter of the invention, independent of all other partial features described in connection therewith, both on its own and in combination with any features of another exemplary embodiment.

[0048] Fig. 1, Fig. 2, Fig. 3 to Fig. Figure 4 shows a braking device 1 comprising at least a first magnetic device 2.1, at least a second magnetic device 2.2, at least one braking element 3, and at least one magnetically conductive rotor 4. One of the two magnetic devices 2.1, 2.2 has at least one electromagnet 5. The other of the two magnetic devices 2.2, 2.1 has at least one permanent magnet 6. The braking element 3 is movable at least between a braking position BP, which is in contact with the rotor 4, and a release position FP, which is spaced apart from the rotor 4.

[0049] Fig. 1 and Fig. Figure 2 shows the brake element 3 in a position between the brake position BP and the release position FP. Fig. 3 and in Fig. 4 on the left shows brake element 3 in brake position BP. Fig. Figure 4 shows the brake element 3 in the release position FP on the right. An air gap s is formed between the brake element 3 in the braking position BP and the first magnet device 2.1. The brake element 3 in the release position FP rests at least partially against the first magnet device 2.1, so that the air gap s is reduced to zero when the brake element 3 is moved from the braking position BP to the release position FP.

[0050] The first magnetic device 2.1 is fixed in position and rotationally fixed. The second magnetic device 2.2 is connected to the braking element 3. When the electromagnet 5 is switched off, the braking element 3 is moved into the braking position BP by the action of the permanent magnet 6. When the electromagnet 5 is switched on, the braking element 3 is moved into the release position FP.

[0051] The switch-on process is characterized by a profile of the supply voltage U of the electromagnet 5 over time t. Fig. Figure 4 illustrates this. The second magnetic device 2.2 is preferably connected to the brake element 3 on a side of the brake element 3 facing away from the first magnetic device 2.1. The second magnetic device 2.2 is preferably arranged on a side of the brake element 3 facing the rotor 4. However, it would also be conceivable to arrange the second magnetic device 2.2 on the side of the brake element 3 facing the first magnetic device 2.1, in which case the second magnetic device 2.2 would be located on the side of the brake element 3 facing away from the rotor 4. Furthermore, the second magnetic device 2.2 could be surrounded by the brake element and thus integrated into the brake element 3.

[0052] The braking element 3 is movable parallel or axially to a rotational axis R of the rotor 4. In its braking position BP, the braking element 3 contacts an end face 4.S of the rotor 4. Preferably, in its braking position BP, the braking element 3 contacts the end face 4.S of the rotor 4 at a radially outer end region, in particular with a collar region of the braking element 3 projecting towards the rotor 4. Such a collar region is provided according to the third embodiment of the braking device 1. Fig. 3 is formed on the brake element 3 at the radially outer end of the brake element 3.

[0053] The second magnetic device 2.2, connected to the brake element 3, has, according to the embodiments shown here, at least one permanent magnet 6. The permanent magnet 6 is arranged on the brake element 3 such that, when the electromagnet 5 is switched off, the brake element 3 is moved into the braking position BP by the magnetic force acting between the permanent magnet 6 and the rotor 4, and that, when the electromagnet 5 is switched on, the brake element 3 can be moved, or is moved, into the release position FP by the magnetic force acting between the brake element 3 and / or the permanent magnet 6 on the one hand and the electromagnet 5 on the other.

[0054] To move the braking element 3 into the braking position BP by means of the magnetic force acting between the permanent magnet 6 and the rotor 4 when the electromagnet 5 is switched off, the polarity of the permanent magnet 6 is aligned accordingly. The electromagnet 5 has at least one coil, preferably wound in a circular fashion. In particular, such a coil is arranged in an end-face receiving groove of a support structure of the first magnet device 2.1. Such a coil preferably surrounds a radially inner core region of such a support structure. The coil is preferably arranged at an end region of the first magnet device 2.1 facing the braking element 3.

[0055] The braking element 3 is supported against rotation relative to the first magnetic device 2.1 at the first magnetic device 2.1 and / or a machine frame 7. The first magnetic device 2.1, in particular its support structure, is connected to the machine frame 7.

[0056] The brake element 3 is connected to the first magnetic device 2.1 by means of a spring element 8, in particular a spring disc. The spring element 8 is elastically deformable to allow axial movement of the brake element 3 between the braking position BP and the release position FP.

[0057] Fig. 1, Fig. 2, Fig. 3 to Fig. Figure 4 shows the spring element 8 in a highly simplified form, each with a dashed line. Fig. Figure 5 shows a separate embodiment of the spring element 8, which can be used in the previously described embodiments of the brake device 1. The spring element 8 in the figure is designed as a spring disc. The spring element 8 is connected to the brake element 3 and to the first magnet device 2.1 by at least one connecting element, in particular by at least one screw, preferably by two to five screws, and most preferably by three screws. The spring element 8 preferably has a through-opening in the axial direction for each connecting element, in which the respective connecting element is arranged.

[0058] The spring element 8, in particular the spring disc, is designed to transmit the braking torques that can be generated between the brake element 3, which is in the braking position BP, and the rotor 4 during operation of the brake device 1. The brake element 3 is supported or attached to the first magnet device 2.1 by the spring element 8 to prevent rotation relative to the first magnet device 2.1.

[0059] The spring element 8, in particular the spring disc, is connected to the first magnet device 2.1 along a first circular path 8.1. The spring element 8, in particular the spring disc, is connected to the brake element 3 along a second circular path 8.2. The diameter of the first circular path 8.1 differs from the diameter of the second circular path 8.2.

[0060] In particular, through-openings for receiving fastening elements are provided on the two circular tracks 8.1, 8.2. Preferably, the second circular track 8.2 has a larger diameter than the first circular track 8.1. The spring element 8 is preferably connected to the first magnetic device 2.1 at a radially inner end region, particularly on the first circular track 8.1. The spring element 8 is preferably connected to the brake element 3 at a radially outer end region, particularly on the second circular track 8.2.

[0061] The spring element 8, in particular the spring disc, has at least one continuous recess 9 which forms at least partially along a circular path along a circumferentially u-shaped section of the spring element 8, in particular the spring disc.

[0062] Preferably, the spring element 8 has two to five, particularly preferably three, recesses 9. Preferably, several recesses 9 each have the same dimensions and / or are evenly distributed in the circumferential direction. The recess 9 is designed according to Fig. 5 arranged radially between the two circular paths 8.1, 8.2. The recess 9 has according to Fig. Figure 5 comprises three areas: an inner circular area 9a, an outer circular area 9b, and a connecting area 9c. The inner circular area 9a is located closer to the center of the spring element 8 than the outer circular area 9b. Viewed in the circumferential direction u, the inner circular area 9a transitions into the outer circular area 9b at the connecting area 9c. Preferably, the inner circular area 9a and the outer circular area 9b of two adjacent recesses 9 overlap in the radial direction, such that a bending area 8a of the spring element 8 is formed between these two areas.

[0063] Alternatively or in addition to the spring element 8, it is conceivable that the brake element 3 is connected to the first magnetic device 2.1 and / or a machine frame 7 by means of a positive locking connection not shown here, which allows movement of the brake element 3 in the axial direction, but in particular prevents rotation of the brake element 3.

[0064] The rotor 4 is rotatably mounted or can be mounted relative to a machine frame 7 by means of a rotor bearing 10. The rotor 4 is fixed axially relative to the machine frame 7 by means of the rotor bearing 10. The rotor bearing 10 has, for example, at least one ball bearing.

[0065] The first magnet device 2.1, the brake element 3, and the rotor 4 each have a cylindrical outer circumference. In particular, the diameters of the first magnet device 2.1, the brake element 3, and the rotor 4 have the same values.

[0066] Preferably, the spring element 8 and / or the second magnet device 2.2 also has a cylindrical outer circumference, preferably with essentially the same values, which correspond in particular to those of the magnet device 2.1, the brake element 3 and the rotor 4.

[0067] Several permanent magnets 6 are arranged along the brake element 3 in concentric circular paths. Fig. 1, Fig. 2, Fig. 3 to Fig. Figure 4 shows an example of the arrangement of permanent magnets 6 along three concentric circular paths. The permanent magnets 6 can also be arranged along two to five concentric circular paths on the braking element 3. The polarity of the permanent magnets 6 relative to each other is optimized to achieve high holding forces. For example, the permanent magnets 6 are arranged in a Halbach array.

[0068] The permanent magnets 6 are advantageously identical in construction and / or cuboid in shape. The use of other types of permanent magnets 6, e.g., circular cylindrical ones, is also possible.

[0069] The contact surfaces between brake element 3 and rotor 4 are designed as steel surfaces or at least one of the contact surfaces has a friction-enhancing layer or coating.

[0070] According to Fig. 3 and Fig. 4 The contact surface of the brake element 3 on the collar region 3a of the brake element 3 is designed, in particular as an end face formed by means of this collar region 3a. The contact surface of the brake element 3 is then annular in shape. Due to the design of this contact surface on the outer collar region 3a or circumferential edge of the brake element 3, high braking or holding torques can be achieved with comparatively low axial forces.

[0071] According to the embodiment, the rotor 4 has Fig. 1. At least one attachment element 11, wherein a contact surface for the brake element 3 is formed on the attachment element 11. The attachment element 11 is preferably designed as a disc. The attachment element 11 is fastened to the rotor 4 and thus becomes part of the rotor 4.

[0072] Based on Fig. Section 4 describes a voltage supply for the electromagnet 5, particularly for a switching process in which the brake element 3 is moved from the braking position BP to the release position FP. The supply voltage U over time t is shown in a diagram. To move the brake element 3 from the braking position BP to the release position FP, the electromagnet 5 is supplied with a constant high voltage U, e.g., approximately 24 V, for a switching time t. Ein This voltage results in an alternating power P1 of, for example, approximately 70 W, which is maintained over the on-time t. Einis maintained throughout. This constantly high supply voltage U allows the brake element 3 to be released from the rotor 4 and moved to the release position FP. To hold the brake element 3 in the release position FP, the electromagnet 5 can be operated with a pulse-width modulated supply voltage U, specifically alternating between 0 V and approximately 24 V. One period t PWM is determined according to a desired effective supply voltage U effThe supply voltage is selected to be approximately 3V, resulting in a holding power P2 of approximately 1.2 W. The braking device 1 with the braking element 3 in the braking position BP is shown over the range of the constantly high supply voltage U. Over the range of the pulse-width modulated supply voltage U, the braking device 1 with the braking element 3 in the release position FP is shown. The braking device 1 preferably has an outer diameter of 30 mm to 50 mm, particularly 40 mm. The braking device 1 preferably has a thickness / height of 8 mm to 12 mm, particularly 10 mm, in the direction of the axis of rotation R. In particular, the braking device 1 has an outer diameter to thickness / height ratio of 3 to 5, particularly 4. A braking torque or holding torque of 0.4 Nm to 0.6 Nm, particularly 0.5 Nm, can be achieved using the braking device 1.

[0073] Fig.Figure 1 also shows an electric motor 12 with the braking device 1 described above. The rotor 4 of the braking device 1 is part of a rotor 13 of the motor 12, so that the motor 12 can be braked by the braking device 1. The machine frame 7 has a sleeve-shaped section that circumferentially encloses the rotor 13 of the electric motor 12 and thus acts as a motor housing. The electric motor 12 is preferably designed as an external rotor motor.

[0074] The electric motor 12, including the brake device 1, preferably has a length of 26 mm to 38 mm, and in particular 32 mm, in the direction of the axis of rotation R. The electric motor 12 is designed in particular as a high-performance drive motor for precision engineering applications.

[0075] The invention is not limited to the embodiments illustrated and described, but also encompasses all embodiments that have the same effect within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual feature can also have inventive significance independently of all other features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features from all disclosed individual features. This means that, in principle, virtually any individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. Reference symbol list 1 Brake device 2.1 First magnetic device 2.2 second magnetic device 3 brake element 3a Collar area 4 Rotor of the brake device 1 4.S Front of the rotor 5 Electromagnet 6 permanent magnets 7 machine frame 8 spring element 8a Bending range 8.1 First circular path of the spring element 8 8.2 second circular path of the spring element 8 9 recess 9a inner circle area 9b outer circle area 9c Connection area 10 Rotor bearing 11 Approach element 12 Electric motor 13 Rotor of the electric motor 12 BP brake position FP Release Position R Rotation axis of the rotor 4 u circumferential direction air gap U Supply voltage of the electromagnet 5 U eff effective supply voltage t time t EinSwitch-on time t PWM Period P1 AC P2 Holding power

Claims

Braking device (1) comprising at least a first magnet device (2.1), at least a second magnet device (2.2), at least one braking element (3) and at least one magnetically conductive rotor (4), wherein one of the two magnet devices (2.1, 2.2) has at least one electromagnet (5), wherein the other of the two magnet devices (2.2, 2.1) has at least one permanent magnet (6), wherein the braking element (3) is movable at least between a braking position (BP) contacting the rotor (4) and a release position (FP) spaced apart from the rotor (4), characterized in that the first magnet device (2.1) is held stationary and rotationally fixed, that the second magnet device (2.2) is connected to the brake element (3) such that the brake element (3) is moved into the braking position (BP) by the action of the permanent magnet (6) when the electromagnet (5) is switched off, and that the brake element (3) is moved into the release position (FP) when the electromagnet (5) is switched on. Braking device (1) according to claim 1, characterized in that the braking element (3) is movable parallel to an axis of rotation (R) of the rotor (4), and that the braking element (3) in its braking position (BP) contacts an end face (4.S) of the rotor (4). Braking device (1) according to claim 1 or 2, characterized in that the second magnetic device (2.2) connected to the braking element (3) has at least one permanent magnet (6), wherein the permanent magnet (6) is arranged on the braking element (3) such that, when the electromagnet (5) is switched off, the braking element (3) is moved into the braking position (BP) by the magnetic force acting between the permanent magnet (6) and the rotor (4), and that, when the electromagnet (5) is switched on, the braking element (3) is moved into the release position (FP) by the magnetic force acting between the braking element (3) and / or the permanent magnet (6) on the one hand and the electromagnet (5) on the other. Braking device (1) according to one of the preceding claims, characterized in that the braking element (3) is supported against rotation relative to the first magnet device (2.1) on the first magnet device (2.1) and / or a machine frame (7). Brake device (1) according to one of the preceding claims, characterized in that the brake element (3) is connected to the first magnet device (2.1) by means of a spring element (8), in particular a spring disc, and that the spring element (8) is elastically deformable to enable the axial movement of the brake element (3) between the braking position (BP) and the release position (FP). Brake device (1) according to claim 5, characterized in that the spring element (8), in particular the spring disc, is designed and configured to transmit the braking torques that can be formed between the brake element (3) positioned in the brake position (BP) and the rotor (4). Brake device (1) according to claim 5 or 6, characterized in that the spring element (8), in particular the spring disc, is connected to the first magnet device (2.1) in the course of a first circular path (8.1), wherein the spring element (8), in particular the spring disc, is connected to the brake element (3) in the course of a second circular path (8.2), and that a diameter of the first circular path (8.1) differs from a diameter of the second circular path (8.2). Brake device (1) according to one of claims 5 to 7, characterized in that the spring element (8), in particular the spring disc, has at least one axially extending recess (9) which forms at least partially in the course of a circular path along a circumferentially extending (u) section of the spring element (8), in particular the spring disc. Brake device (1) according to one of the preceding claims, characterized in that the brake element (3) is connected to the first magnet device (2.1) and / or a machine frame (7) by means of a positive locking connection which enables movement of the brake element (3) in the axial direction. Brake device (1) according to one of the preceding claims, characterized in that the rotor (4) is rotatably mounted or mountable relative to a machine frame (7) by means of a rotor bearing (10), and that the rotor (4) is fixed in the axial direction relative to the machine frame (7) by means of the rotor bearing (10). Brake device (1) according to one of the preceding claims, characterized in that the first magnet device (2.1), the brake element (3) and the rotor (4) each have a cylindrical outer circumference and / or the diameters of the first magnet device (2.1), the brake element (3) and the rotor (4) have the same values. Brake device (1) according to one of claims 3 to 11, characterized in that several permanent magnets (6) are arranged on the brake element (3) along mutually concentric circular paths. Brake device (1) according to claim 12, characterized in that the permanent magnets (6) are identical in construction and / or cuboid in shape. Brake device (1) according to one of the preceding claims, characterized in that the contact surfaces between brake element (3) and rotor (4) are designed as steel surfaces and / or that at least one of the contact surfaces has a friction-enhancing layer or coating. Brake device (1) according to one of the preceding claims, characterized in that the rotor (4) has at least one attachment element (11) and that a contact surface for the brake element (3) is formed on the attachment element (11). Brake device (1) according to one of the preceding claims, characterized in that the brake device (1) is designed to be suitable for hollow shafts, in particular the first magnet device (2.1), the brake element (3) and the rotor (4) each have a central opening through which a shaft or other components can be passed. Braking device (1) according to one of the preceding claims, characterized in that at least one control electronics is included, and that the control electronics are designed and configured to operate the electromagnet (5) with at least two different electrical powers, in particular with a first, larger electrical power for moving it into the release position and with a second, lower electrical power for holding the release position. Braking device (1) according to claim 17, characterized in that the control electronics are designed and configured to realize at least the low power by means of pulse width modulation of the voltage. Electric motor (12) comprising at least one braking device (1) according to one of claims 1 to 18, wherein the rotor (4) of the braking device (1) is part of a rotor (13) of the motor (12) so that the motor (12) can be braked with the braking device (1).

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