ELECTROMECHANICAL DRIVE

Description

[0001] The invention relates to an electromechanical drive according to the preamble of claim 1. The invention also relates to a forming machine with a press drive.

[0002] EP1524455A2 discloses, in connection with an electrically operated linear actuator in the form of a spindle drive, a braking device comprising an axially movable first clutch disc and a second clutch disc that interacts with the drive shaft via a hub. The first clutch disc presses the second clutch disc against a third clutch disc. By actuating a coil, the first clutch disc is moved into a release position, allowing the second clutch disc to rotate with the drive shaft.

[0003] EP2333380A1 also discloses, in connection with a linear actuator, a braking device with a rotating brake disc and a stationary brake disc, which is movable relative to the rotating brake disc and enables braking of the drive shaft by friction.

[0004] DE102019004953A1 discloses a braking and / or clamping device for a shaft guided relative to a base body, comprising an actuating assembly and a shaft connection assembly that has a slotted or multiply split ring as the brake disc. The actuating assembly has an elastic split housing whose jaws rest against the brake disc like pincers during braking or clamping.

[0005] The disadvantages resulting from the prior art are, in particular, that the braking effect, especially the braking torque or braking force, is too low for certain applications. The braking process, i.e., the time between actuation of the braking device and the braking effect (e.g., standstill of the drive or deceleration to a desired level), is often too long.

[0006] The objective of the present invention was to overcome the disadvantages of the prior art and to provide an electromechanical drive capable of achieving an immediate and rapid braking effect. The braking effect and efficiency of the braking process should also be increased. This is intended to increase safety, particularly in applications where operators work or handle hazardous areas and, for this reason, drives must come to an immediate standstill under certain conditions. The reliability, performance, and usability of an electromechanical drive in a wide variety of applications should be enhanced by improving the braking system.

[0007] This task is solved by an electromechanical drive of the type mentioned above in that the brake disc an inner region, a friction surface region extending annularly around the rotation axis with a first friction surface formed on a first side of the brake disc and a second friction surface formed on the second side of the brake disc opposite the first side, and an intermediate region extending between the friction surface region and the inner region around the rotation axis, and that a first counter-surface is formed on the braking element, which faces the first friction surface and cooperates with the first friction surface in the braking position, and wherein the friction surface region of the brake disc is arranged between the first counter-surface and a second counter-surface which faces the second friction surface and cooperates with the second friction surface in the braking position, characterized in that the intermediate region is a deformation region which is elastically deformable in the axial direction by the action of the braking element on the brake disc, and that in the released position of the braking device the first friction surface and the first counter-surface deviate from a parallel alignment and / or are inclined to one another and / or the second friction surface and the second counter-surface deviate from a parallel alignment and / or are inclined to one another.

[0008] The braking element does not rotate with the rotating part. In other words, the braking element is stationary with respect to the rotation of the rotating part or of the brake disc rotationally connected to the rotating part. In the braking position, the braking element exerts a braking effect through frictional engagement with the brake disc. According to the invention, the friction surface region is located radially outside the inner region and also outside the intermediate region. While the inner region can serve as a fastening region (for fastening to the rotating part), the intermediate region is preferably designed to be deformable. It is preferred if the inner region and the intermediate region are not in contact with the braking element even in the braking position. The braking effect is greatest in the peripheral region. On the one hand, the speed is greatest there, and on the other hand, the greatest braking torque can be applied there.

[0009] The brake element can be moved axially from the released position to the braking position. This movement reduces the braking gap until the brake element presses with its first counter surface against the first friction surface of the brake disc.

[0010] The braking torque is transferred to the rotating part via the radially inner areas (inner area and intermediate area).

[0011] The brake disc can be axially fixed with its inner region relative to the rotating part. In the braking position, the braking element presses against the outer friction surface area, exerting a deformation force on the brake disc. The latter tends to bend in the axial direction.

[0012] The rotating part can be, for example, a drive shaft, a threaded nut (e.g. in a spindle drive), a rotor (of an electric motor) or any rotating element of a drive train.

[0013] A preferred embodiment is characterized in that the intermediate region of the brake disc—both in the released position and in the braking position—is free of contact with the braking element, and / or that, in the braking position, the contact of the braking element with the brake disc is limited to the first friction surface. This measure ensures that the frictional engagement occurs only in the area of ​​the friction surface, while the inner region and the intermediate region do not come into direct contact with the braking element. The intermediate region, in particular, can thus perform an additional functionality.

[0014] The invention is characterized in that the intermediate region is a deformation region that is elastically deformable in the axial direction due to the action of the braking element on the brake disc. In contrast to known solutions, the brake disc can be axially fixed to the rotating part. In general, a rigid connection between the brake disc and the rotating part can be provided. This increases the braking effect, in particular, the braking force is transmitted directly to the rotating part.

[0015] A preferred embodiment is characterized by the formation of cutouts, preferably in the form of perforations, and / or material weakenings in the deformation area. The number of cutouts allows the degree of deformability to be determined and optimized for different applications. Alternatively, the deformation area can also be characterized by a thinner material thickness compared to the inner area and / or friction surface area.

[0016] A preferred embodiment is characterized in that the total area of ​​the cutouts in the deformation region is at least as large as the total area occupied by the remaining material. This ensures sufficient deformation, particularly in the event that the friction surface area is pressed against a second counter surface in the braking position.

[0017] The invention is characterized in that the friction surface region has a second friction surface which is formed on the second side of the brake disc opposite the first side, and in that the friction surface region of the brake disc is arranged between the first counter-surface and a second counter-surface which faces the second friction surface and interacts with the second friction surface in the braking position. In the released position of the braking device, a braking gap is formed between the respective interacting surfaces. By means of a deformable intermediate region, it can be ensured in an elegant manner - and as an alternative to axial displaceability of the brake disc relative to the rotating part - that the braking gap(s) are closed over their entire surface by deformation of the brake disc in the axial direction.

[0018] A preferred embodiment is characterized in that the first counter surface is annular and / or that the second counter surface is annular.

[0019] A preferred embodiment is characterized in that the friction surface region is arranged in the periphery of the brake disc, with the first friction surface and / or the second friction surface preferably extending to the outer edge of the brake disc. As already mentioned, the braking effect is greatest in the outermost region of the brake disc.

[0020] A preferred embodiment is characterized in that the difference between the outer radius and the inner radius of the friction surface area is at most 1 / 3, preferably at most 1 / 4, of the outer radius of the brake disc.

[0021] A preferred embodiment is characterized in that the electromechanical drive has a housing, and in that the second counter surface is formed on a housing part or on an element firmly connected to the housing part. This measure allows the braking torque to be introduced directly into the (stationary) housing. The braking energy dissipated in the form of heat can also be transferred to the housing, thus eliminating the need for complex brake cooling, as the heat can be conducted directly to the outside via the housing.

[0022] A preferred embodiment is characterized in that the inner region of the brake disc has at least one, preferably several—preferably arranged in a ring shape—attachment interfaces, preferably in the form of holes, for attaching the brake disc to the rotating part. Preferably, the number of attachment interfaces is greater than 10 and / or greater than the number of cutouts in the deformation region. A rigid connection between the brake disc and the rotating part is particularly preferred, which can be ensured, for example, by screws.

[0023] A preferred embodiment is characterized in that in the released position of the braking device the first friction surface and the first counter surface deviate from a parallel alignment and / or that in the released position of the braking device the second friction surface and the second counter surface deviate from a parallel alignment. With this measure, for example, the pressure in a more inner section of the friction surface area can be reduced, while it can be increased relative to it in a more outer section. As a result, with appropriate dimensioning of the friction or counter surface(s) (or the brake gap) a more even pressure distribution can be achieved. This leads to less wear and an increased service life. These advantages can also be achieved, for example, by the following preferred embodiments.

[0024] A preferred embodiment is characterized by that the distance between the first friction surface and the first counter-surface decreases in the radial direction, wherein preferably this distance is smaller by at most 1 mm, preferably by at most 0.2 mm, at the radially outer edge of the first friction surface than at the radially inner edge of the first friction surface, and / or that the distance between the second friction surface and the second counter-surface decreases in the radial direction, wherein preferably this distance is smaller by at most 1 mm, preferably by at most 0.2 mm, at the radially outer edge of the second friction surface than at the radially inner edge of the second friction surface.

[0025] In the braking position, the pressure is then reduced at a more inward section of the friction surface area, while it is increased relative to it in a more outward section. This also allows for a certain degree of adaptation to a brake disc that bends axially during the braking process.

[0026] A preferred embodiment is characterized in that in the released position of the braking device the first friction surface and the first counter surface are inclined towards each other and / or that in the released position of the braking device the second friction surface and the second counter surface are inclined towards each other.

[0027] A preferred embodiment is characterized in that the first friction surface and / or the first counter surface have a curved course in the radial direction and / or that the second friction surface and / or the second counter surface have a curved course in the radial direction.

[0028] A preferred embodiment is characterized in that the inner region of the brake disc is axially fixed to the rotating part and / or that the inner region of the brake disc is rigidly connected to the rotating part, preferably via screws.

[0029] A preferred embodiment is characterized by a first spacer ring being arranged between the inner region of the brake disc and the rotating part, wherein the inner region of the brake disc is preferably clamped between the first spacer ring and a second spacer ring, preferably by means of screws. The spacer ring(s) can be used to adjust or optimize the relative position of the friction surface(s) relative to the counter surface(s). They also ensure even pressure distribution.

[0030] A preferred embodiment is characterized in that the electromechanical drive is a spindle drive, wherein the rotating part to which the brake disc is connected is designed in the form of a threaded nut which cooperates with the spindle of the spindle drive.

[0031] A preferred embodiment is characterized in that the brake disc has a disc-shaped base body and that the first friction surface and / or the second friction surface is formed by a preferably annular brake pad which is applied to the base body and / or protrudes beyond the base body in the axial direction.

[0032] A preferred embodiment is characterized by the fact that the braking element is preloaded toward the braking position. Independent of actuation or current supply, the braking position can be maintained by passive (spring) elements.

[0033] A preferred embodiment is characterized in that the braking element is pretensioned in the direction of the braking position by a plurality of springs which are arranged in a ring shape and preferably overlapping with the first counter surface.

[0034] A preferred embodiment is characterized in that the springs are inserted in a removable housing part of the electromechanical drive.

[0035] A preferred embodiment is characterized in that the braking device comprises an actuator, preferably in the form of an electromagnet, by which the braking element can be brought into the released position and / or into the braking position. Preferably, the actuator is installed in a removable housing part of the electromechanical drive. Such a variant has the advantage that in the event of a power failure or a control error, the electromagnets are de-energized and the braking device automatically falls into the braking position.

[0036] A preferred embodiment is characterized by the fact that the motor and the braking device are housed in a common housing. This increases the immediacy of the braking effect, since braking occurs in the immediate area where the motor torque is generated.

[0037] This objective is also achieved with a forming machine, in particular a bending machine, preferably a bending press, having at least one drive for the working movement, in particular a press drive, wherein the at least one drive is an electromechanical drive according to the invention. Such a forming machine can comprise a first (e.g., upper) tool carrier and a second (e.g., lower) tool carrier, the relative movement of which is the working movement. The electromechanical drive described above is particularly well suited for use in a forming machine, since the proposed braking device reacts particularly quickly and thus reliably protects, in particular, the operating personnel (especially in cases where a shutdown or a stop / slowing down of the working movement is relevant for safety), but also workpieces are "protected" from incorrect or faulty processing routines.

[0038] For a better understanding of the invention, it is explained in more detail using the following figures.

[0039] They show in a highly simplified, schematic representation: Fig. 1 shows an electromechanical drive in section; Fig. 2 shows a detail of a braking device with a perspective view; Fig. 3 shows a braking device in section; Fig. 4 shows a brake disc; Fig. 5 shows the interaction of the braking element and the brake disc; Fig. 6 shows a braking device in the released position; Fig. 7 shows a braking device in the released position; Fig. 8 shows a braking device with a second braking and counter surface in the released position; Fig. 9 shows a braking device with a second braking and counter surface in the released position; Fig. 10 shows a braking device with a pre-tensioned braking element; Fig. 11 shows a housing part with receptacles for springs and a receptacle for an actuator; Fig. 12 shows a forming machine, in the form of a bending press, with electromechanical drives.

[0040] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0041] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0042] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0043] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0044] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size.

[0045] Fig. 1shows an electromechanical drive 1 comprising a motor 2 and a rotating part 3, which can be set in rotation about a rotation axis 4 by the motor 2. The motor has a stator 2a, which is mounted on the inside of the housing 13 (e.g., in the form of windings), and a rotor 2b, which is arranged on the rotating part 3 (e.g., in the form of permanent magnets).

[0046] The electromechanical drive 1 further comprises a braking device 5 which can be actuated between a braking position and a released position. The braking device 5 has a brake disc 6 which rotates with the rotating part 3 and a braking element 7 which is adjustable in the axial direction and which acts on the brake disc 6 in the braking position (see also Fig. 2 and 3 ).

[0047] Out of Fig. 4 it is clear that the brake disc 6 an inner region 8, a friction surface region 10 extending annularly around the rotation axis 4 with a first friction surface 11 formed on a first side of the brake disc 6, and an intermediate region 9 extending between the friction surface region 10 and the inner region 8 around the rotation axis 4, can have.

[0048] A first counter surface 17 is formed on the braking element 7, which faces the first friction surface 11 and interacts with the first friction surface 11 in the braking position.

[0049] Preferably, the motor 2 and the braking device 5 are accommodated in a common housing 13.

[0050] In the preferred embodiment shown, the intermediate region 9 of the brake disc 6 - both in the released position and in the braking position - is contact-free with the braking element 7. In the braking position, the contact of the braking element 7 with the brake disc 6 is limited to the first friction surface 11 (see Fig. 2 , 7 and 9 ). As for example from Fig. 5 As can be seen, the areas of the braking element 7 adjacent to the first counter surface 17 can be set back behind the counter surface 17.

[0051] In the Fig. 4 In the preferred embodiment of the brake disc 6 shown, the intermediate region 9 is a deformation region which is elastically deformable in the axial direction by the action of the braking element 7 on the brake disc 6 (see Figs. 7 and 9 ).

[0052] In the deformation area, as in Fig. 4shown - cutouts 19, preferably in the form of perforations, and / or material weakenings. It is preferred if the total area of ​​the cutouts 19 in the deformation region is at least as large as the total area occupied by the remaining material.

[0053] While the embodiments according to Fig. 5-7 have only a first friction and counter surface, the variants of the Fig. 1-3 as well as Figs. 8 and 9 that the friction surface region 10 can have a second friction surface 12, which is formed on the second side of the brake disc 6, opposite the first side. The friction surface region 10 of the brake disc 6 is arranged between the first counter surface 17 and a second counter surface 18, which faces the second friction surface 12 and interacts with the second friction surface 12 in the braking position.

[0054] The brake disc 6 has a disc-shaped base body 24. The first friction surface 11 and the second friction surface 12 are each formed by a preferably annular brake pad, which is applied to the base body 24 and / or protrudes in the axial direction beyond the base body 26 ( Fig. 5-9 ).

[0055] The first counter surface 17 and the second counter surface 18 are each ring-shaped. Several interrupted counter surface areas, e.g., arranged in segments, would also be conceivable.

[0056] As from Fig. 4 As can be clearly seen, the friction surface region 10 is preferably arranged in the periphery of the brake disc 6. The first friction surface 11 and / or the second friction surface 12 can extend to the outer edge of the brake disc 6. The difference between the outer radius and the inner radius of the friction surface region 10 is preferably at most 1 / 3, preferably at most 1 / 4, of the outer radius of the brake disc 6.

[0057] Fig. 1 and 3 show that the electromechanical drive 1 has a (multi-part) housing 13. The second counter surface 18 can be formed on a housing part 13a or on an element firmly connected to the housing part 13a. In this way, the braking torque and the resulting frictional heat can be introduced directly into the housing.

[0058] In the Fig. 4 In the embodiment shown, the inner region 8 of the brake disc 6 has a plurality of fastening interfaces 16—here arranged in a ring shape—preferably in the form of holes, for fastening the brake disc 6 to the rotating part 3. The number of fastening interfaces 16 is preferably greater than 10 and / or greater than the number of cutouts 19 in the deformation region. A large number of fastening interfaces allows for particularly precise adjustment of the brake disc relative to the mating surfaces.

[0059] In the variants of the Fig. 6-9 In the released position of the braking device 5, the first friction surface 11 and the first counter surface 17 deviate from a parallel alignment. Likewise, the second friction surface 12 and the second counter surface 18 could deviate from a parallel alignment.

[0060] Preferably, the distance between the first friction surface 11 and the first counter surface 17 decreases in the radial direction, wherein this distance is preferably smaller by at most 1 mm, preferably by at most 0.2 mm, at the radially outer edge of the first friction surface 11 than at the radially inner edge of the first friction surface 11.

[0061] Likewise, the distance between the second friction surface 12 and the second counter surface 18 can decrease in the radial direction, wherein this distance is preferably smaller by at most 1 mm, preferably by at most 0.2 mm, at the radially outer edge of the second friction surface 12 than at the radially inner edge of the second friction surface 12.

[0062] The friction surfaces and counter surfaces can be inclined relative to each other. The friction surfaces and counter surfaces can also have a curved shape in the radial direction.

[0063] As can be seen in particular from the Figures 1-3 As can be seen, the inner region 8 of the brake disc 6 can be axially fixed to the rotating part 3. In the illustrated embodiments, the inner region 8 of the brake disc 6 is rigidly connected to the rotating part 3. This is done here by means of screws that pass through the holes (fastening interfaces 16; see Fig. 4 ) and press the brake disc against the rotating part 3.

[0064] In the embodiment of the Fig. 3 It can be seen that a first spacer ring 14 is arranged between the inner region 8 of the brake disc 6 and the rotating part 3. The inner region 8 of the brake disc 6 is also clamped between the first spacer ring 14 and a second spacer ring 15. This is done with the same screws mentioned above that firmly connect the brake disc 7 to the rotating part 3.

[0065] In the preferred variant shown, the electromechanical drive 1 is a spindle drive, wherein the rotating part 3, to which the brake disc 6 is connected, is designed in the form of a threaded nut, which interacts with the spindle 23 of the spindle drive. The lower end of the spindle 23 moves - upon actuation of the motor and rotation of the threaded nut (rotating part 3) - linearly along the rotation axis 4 downwards or upwards ( Fig. 1 ).

[0066] Preferably, the braking element 7 is pre-tensioned in the direction of the braking position. Figs. 10 and 11 Finally, show that the braking element 7 is preloaded in the direction of the braking position by a plurality of springs 21 which are arranged in a ring shape and preferably overlapping with the first counter surface 17.

[0067] The springs 21 can be inserted in a removable housing part 13b (e.g. in the form of a cover or a front cover) of the electromechanical drive 1.

[0068] In the Fig. 1-3 and 10 It can be seen that the braking device 5 comprises an actuator 22, preferably in the form of an electromagnet, by which the braking element 6 can be brought into the released position and / or into the braking position. The actuator 22, like the springs 21, can be installed in a removable housing part 13b of the electromechanical drive 1.

[0069] Fig. 12Finally, FIG. 2 shows a forming machine 20 in the form of a bending press, with at least one drive for the working movement (of a forming tool), in particular a press drive. The drive or drives are designed as electromechanical drive(s) 1 according to the invention. Such a forming machine can comprise a first (e.g., upper) tool carrier and a second (e.g., lower) tool carrier, the relative movement of which is the working movement. The electromechanical drive described above is particularly well suited for use in a bending machine, since the proposed braking device reacts particularly quickly and thus reliably protects, in particular, the operating personnel (especially in cases where a shutdown or a stop / slowing down of the working movement is relevant for safety), but also workpieces are "protected" from incorrect or faulty processing routines. Reference symbol list

[0070] 1 Electromechanical drive 2 Motor 2a, 2b Stator, rotor 3 Rotating part 4 Rotational axis 5 Braking device 6 Brake disc 7 Braking element 8 Inner area 9 Intermediate area 10 Friction surface area 11 First friction surface 12 Second friction surface 13 Housing 13a Housing part 13b Housing part 14 First spacer ring 15 Second spacer ring 16 Fastening interface 17 First counter surface 18 Second counter surface 19 Cutouts 20 Forming machine 21 Spring 22 Actuator 23 Spindle 24 Base body 25 First tool holder 26 Second tool holder 27 Workpiece

Claims

1. An electromechanical drive (1) comprising - a motor (2), - a rotational part (3), said rotational part being rotatable by the motor (2) about a rotational axis (4), and - a braking device (5) that can be actuated between a braking position and a released position, the braking device (5) having a brake disc (6) that rotates with the rotational part (3) and a braking element (7) that can be adjusted in the axial direction and acts on the brake disc (6) in the braking position, wherein the brake disc (6) has - an inner area (8), - a friction surface area (10) extending annularly around the rotational axis (4) with a first friction surface (11) formed on a first side of the brake disc (6), and a second friction surface (12) formed on a second side of the brake disc (6) opposite the first side, and - an intermediate area (9) extending between the friction surface area (10) and the inner area (8) around the rotational axis (4), and wherein a first mating surface (17) is formed on the braking element (7), which mating surface faces the first friction surface (11) and interacts with the first friction surface (11) in the braking position, and wherein the friction surface (10) of the brake disc (6) is arranged between the first mating surface (17) and a second mating surface (18) which faces to the second friction surface (12) and cooperates with the second friction surface (12) in the braking position, characterised in that the intermediate area (9) is a deformation area that is elastically deformable in the axial direction by the action of the braking element (7) on the brake disc (6), and that, in the released position of the braking device (5), the first friction surface (11) and the first mating surface (17) deviate from a parallel alignment and / or are inclined towards each other and / or the second friction surface (12) and the second mating surface (18) deviate from a parallel alignment and / or are inclined towards each other.

2. The electromechanical drive according to claim 1, characterised in that the intermediate region (9) of the brake disc (6), both in the released position and in the braking position, is free of contact with the braking element (7) and / or that in the braking position the contact of the braking element (7) with the brake disc (6) is limited to the first friction surface (11).

3. The electromechanical drive according to one of the preceding claims, characterised in that cut-outs (19), preferably in the form of perforations, and / or material weakenings are formed in the deformation area.

4. The electromechanical drive according to claim 3, characterised in that in the deformation area, the total area of the cut-outs (19) is at least as large as the total area occupied by the remaining material.

5. The electromechanical drive according to one of the preceding claims, characterised in that the first mating surface (17) is annular and / or that the second mating surface (18) is annular.

6. The electromechanical drive according to one of the preceding claims, characterised in that the friction surface area (10) is arranged in the periphery of the brake disc (6), wherein preferably the first friction surface (11) and / or the second friction surface (12) extend to the outer edge of the brake disc (6).

7. The electromechanical drive according to one of the preceding claims, characterised in that the difference between the outer radius and the inner radius of the friction surface area (10) is at most 1 / 3, preferably at most 1 / 4, of the outer radius of the brake disc (6).

8. The electromechanical drive according to one of the preceding claims, characterised in that the electromechanical drive (1) has a housing (13) and that the second mating surface (18) is formed on a housing part (13a) or on an element firmly connected to the housing part (13a).

9. The electromechanical drive according to one of the preceding claims, characterised in that the inner region (8) of the brake disc (6) has at least one, preferably several, preferably annularly arranged, attachment interfaces (16), preferably in the form of holes, for attaching the brake disc (6) to the rotational part (3), wherein preferably the number of attaching interfaces (16) is greater than 10 and / or greater than the number of cut-outs (19) in the deformation area.

10. The electromechanical drive according to one of the preceding claims, characterised in that the distance between the first friction surface (11) and the first mating surface (17) decreases in the radial direction, wherein preferably this distance is smaller at the radially outer edge of the first friction surface (11) by at most 1 mm, preferably by at most 0.2 mm, than at the radially inner edge of the first friction surface (11), and / or the distance between the second friction surface (12) and the second mating surface (18) decreases in the radial direction, wherein preferably this distance is smaller at the radially outer edge of the second friction surface (12) by at most 1 mm, preferably by at most 0.2 mm, than at the radially inner edge of the second friction surface (12).

11. The electromechanical drive according to one of the preceding claims, characterised in that the first friction surface (11) and / or the first mating surface (17) have a curved shape in the radial direction and / or that the second friction surface (12) and / or the second mating surface (18) have a curved shape in the radial direction.

12. The electromechanical drive according to one of the preceding claims, characterised in that the inner area (8) of the brake disc (6) is axially fixed to the rotational part (3) and / or that the inner area (8) of the brake disc (6) is rigidly connected to the rotational part (3), preferably by screws.

13. The electromechanical drive according to one of the preceding claims, characterised in that a first spacer ring (14) is arranged between the inner region (8) of the brake disc (6) and the rotational part (3), wherein preferably the inner region (8) of the brake disc (6) is constrained between the first spacer ring (14) and a second spacer ring (15), preferably by screws.

14. The electromechanical drive according to one of the preceding claims, characterised in that the electromechanical drive (1) is a spindle drive, wherein the rotational part (3) to which the brake disc (6) is connected is configured as a threaded nut which cooperates with the spindle (23) of the spindle drive.

15. The electromechanical drive according to one of the preceding claims, characterised in that the brake disc (6) has a disc-shaped base body (24) and that the first friction surface (11) and / or the second friction surface (12) are formed by a preferably annular brake lining which is applied to the base body (24) and / or projects in the axial direction beyond the base body (26).

16. The electromechanical drive according to one of the preceding claims, characterised in that the brake element (7) is biased towards the braking position.

17. The electromechanical drive according to claim 16, characterised in that the braking element (7) is biased towards the braking position by a plurality of springs (21) arranged in an annular manner and preferably overlapping with the first mating surface (17).

18. The electromechanical drive according to claim 17, characterised in that the springs (21) are inserted in a removable housing part (13b) of the electromechanical drive (1).

19. The electromechanical drive according to one of the preceding claims, characterised in that the braking device (5) comprises at least one actuator (22), preferably in the form of an electromagnet, by means of which the braking element (6) can be brought into the released position and / or into the braking position, wherein preferably the actuator (22) is inserted in a removable housing part (13b) of the electromechanical drive (1).

20. The electromechanical drive according to one of the preceding claims, characterised in that the motor (2) and the braking device (5) are housed in a common housing (13).

21. A forming machine (20), in particular a bending machine, preferably a bending press, with at least one drive for the working movement, in particular a press drive, characterised in that the at least one drive is an electromechanical drive (1) according to one of the preceding claims.