Method for manufacturing an electromechanical brake

Abstract

The present invention relates to a method for manufacturing an electromechanical brake (1) comprising an excitation system (20), an armature (40), a restoring means (10) and a tribological system (80), wherein the excitation system (20) comprises a magnet housing (30) and an energizable coil (22), wherein the armature (40) is movable along a longitudinal axis (L) against a restoring force of the restoring means (10), and wherein the tribological system (80) comprises at least one first friction surface (81) and at least one second friction surface (82), wherein the at least one first friction surface (81) and the at least one second friction surface (82) can be brought into operative contact to generate a braking force, wherein the method comprises generating the at least one first friction surface (81) and / or the at least one second friction surface (82) by applying a coating (83) by means of a thermal spraying process.

Description

[0001] The invention relates to a method for manufacturing an electromechanical brake with the features of claim 1 and to an electromechanical brake, in particular a permanent magnet brake or spring pressure brake, according to the features of claim 6.

[0002] Electromechanical brakes are known in various designs from the prior art. For example, permanent magnet brakes or spring-applied brakes are widely used in the prior art. Electromechanical brakes have an energizable excitation system with an energizable coil, which allows the electromechanical brake to be actuated, released, or disengaged against the force of a restoring element. In the actuated electromechanical brake, friction surfaces of a tribological system come into operative contact to generate the braking force.

[0003] For example, as the name suggests, permanent magnet brakes use permanent magnets as a restoring element. When the excitation system is de-energized, the brake is actuated by the permanent magnets to achieve an emergency stop, for example, in the event of a power failure. To provide the highest possible braking torque, it is advisable to optimize the magnetic flux guidance generated by the permanent magnets within the brake. It is advantageous if the friction surfaces of a tribological system are also made of a ferromagnetic material. Therefore, steel-on-steel friction systems are frequently used. These have the disadvantage that the friction surfaces exhibit increased wear, especially under high loads. Due to the significant wear of the friction surfaces and the associated loose particles in the system, braking performance repeatedly drops, particularly in larger permanent magnet brakes.

[0004] DE 10 2014 10 91 25 A1 describes an electromagnetic brake with a pot-shaped magnet housing having external and internal poles. The external and internal poles are profiled so that wear debris can be dissipated, thus ensuring high torque stability.

[0005] Such electromagnetic brakes have proven their worth in the past, however, it has been shown that under high dynamic loads the braking torque can be reduced due to uncarried-away abrasion.

[0006] The present invention is therefore dedicated to the task of proposing a suitably improved method for manufacturing an electromechanical brake as well as a suitably improved electromechanical brake which eliminates the disadvantages known from the prior art.

[0007] These problems are solved by a method for manufacturing an electromechanical brake with the features of claim 1 and an electromechanical brake with the features of claim 7.

[0008] Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0009] According to the invention, a method for manufacturing an electromechanical brake comprises an excitation system, an armature, a restoring element, and a tribological system. The excitation system comprises a magnet housing and an energizable coil. The armature is movable along a longitudinal axis against a restoring force of the restoring element, particularly when the coil is energized. The tribological system comprises at least one first friction surface and at least one second friction surface, wherein the at least one first friction surface and the at least one second friction surface can be brought into operative contact to generate a braking force. The method provides that the at least one friction surface and / or the at least one second friction surface are produced by applying a coating, in particular a hard metal coating, using a thermal spraying process.

[0010] It should be noted here that the coil can also be formed from several individual coils, which allows for higher dynamics and thus faster braking.

[0011] The present invention is based on the idea that the at least one first friction surface and / or the at least one second friction surface are formed by a coating, in particular by a hard metal coating. According to the invention, the coating has a surface finish that is as hard and resistant as possible in order to reduce wear, especially under high loads. A certain degree of wear is desirable, as this allows the friction surfaces to be restored.

[0012] Furthermore, for high braking performance, it is usually advantageous if the roughness of the friction surfaces has an optimized value.

[0013] Since, especially in the case of permanent magnet brakes, the friction surfaces lie within the magnetic flux path of the permanent magnets that provide the braking force of the brake, it is recommended to make the friction surfaces from a material with good magnetic flux conductivity.

[0014] A coating, particularly a hard metal coating, is applied using a thermal spraying process, resulting in high hardness and good average surface roughness. Furthermore, friction surfaces formed by or interacting with the coating are less susceptible to corrosion.

[0015] When carrying out the process, it is advantageous if, prior to applying the coating, in particular the hard metal coating, a preparation, in particular of the substrate, preferably by means of a cleaning and / or roughening process, is carried out.

[0016] The cleaning process aims to remove oils, greases, dirt, and other contaminants from the surface to be coated. Accordingly, the cleaning process may include chemical degreasing and / or blasting, in particular sandblasting, and / or grinding on the surface to be coated.

[0017] To ensure better adhesion of the coating, particularly to the substrate, it is advantageous to roughen the surface using a roughening process. This is often achieved by blasting with sand, corundum, or other abrasive materials. It can also be beneficial to heat the substrate before or after coating application using a thermal spraying process. This minimizes stress within the coating and increases its adhesion strength.

[0018] Advantageously, the thermal spraying process is implemented as a flame spraying process, preferably as a high-speed flame spraying process.

[0019] In the flame spraying process, the coating material is fed in powder form to an energy source inside or outside a burner. The powder is then passed through the spray gun, typically using nitrogen as the carrier gas. The ignited gas surrounds and heats the powdered coating material uniformly as it is propelled at high speed onto the first and / or second friction surface to be coated. Due to the high kinetic energy transferred to the powder particles, the coating material does not need to be completely melted.

[0020] In the high-speed flame spraying process, a distinction is made between general high-speed flame spraying, high-speed flame spraying with liquid fuel, and high-speed flame spraying with fuel gas.

[0021] High-speed flame spraying differs from simple flame spraying in that the exit velocity of the spray material from the spray gun is significantly higher. The high speed at which the spray material particles impact the first and / or second frictional surface to be coated leads to greater deformation and better bonding of the spray material particles to one another, resulting in lower porosity and higher hardness values.

[0022] In high-speed flame spraying, a combustible mixture is formed from oxygen and fuel.

[0023] High-speed flame spraying with liquid fuel typically uses liquid kerosene as fuel.

[0024] High-speed flame spraying with fuel gases utilizes gases such as propylene, propane, hydrogen, or natural gas. The fuel is mixed uniformly with oxygen in the spray gun. The mixture is then combusted and exits through a nozzle at supersonic speed.

[0025] In addition to flame spraying, arc spraying or plasma spraying can also be used as thermal spraying processes.

[0026] It should be noted here that it is advantageous if at least one first friction surface and / or at least one second friction surface does not require reworking, which can result in cost advantages.

[0027] Preferably, the at least one first friction surface and / or the at least one second friction surface can be post-processed, preferably by means of a grinding and / or blasting process, so that a predetermined roughness is achieved.

[0028] In particular, it may be preferred if the at least one first friction surface and / or the at least one second friction surface is reworked after the coating has been applied, preferably by means of a grinding and / or blasting process, so that a predetermined roughness of the coating is achieved.

[0029] The grinding process can be used to achieve specific tolerances that cannot be met when applying the coating using a thermal spraying process. It can also smooth the surface. In some applications, a smooth surface can improve the adhesion between a primary and secondary friction surface, and the improved magnetic transfer can increase the axial force on the armature. Abrasive materials such as aluminum oxide or diamond grinding wheels are used as grinding materials. This depends on the hardness and type of coating being applied. The desired final roughness can be adjusted by selecting the appropriate grit size. For example, a coarser grit is used for rough grinding, resulting in a high surface roughness. Finer grit tools are used for fine grinding.

[0030] The blasting process, particularly sandblasting, can be used to clean or further roughen the coating surface. Blasting removes residues from the thermal spraying process, such as oxides. It can also help reduce stresses within the coating that may have arisen during application.

[0031] Preferably, the excitation system, the restoring means and the anchor are assembled with a working air gap, preferably after the first and / or second friction surface has been produced and / or finished.

[0032] The excitation system is preferably formed by pressing or inserting the coil, together with a support, into an axial annular groove of the magnet housing. The support can be a plastic housing on which the coil is arranged, for example, by winding. Subsequently, at least one restoring element, preferably at least one spring or at least one permanent magnet, can be inserted into or attached to the magnet housing. A flange can also be arranged on the magnet housing. The flange can, for example, preferably partially close the axial annular groove and thus prevent the coil from being removed from the axial annular groove.

[0033] In permanent magnet brakes, the armature can be connected to a flange hub in a rotationally fixed manner, for example, via segment springs and rivets. The flange hub can be positively connected to a motor shaft.

[0034] According to a further advantageous process step, the tribological system, i.e., the at least one first friction surface and / or the at least one second friction surface, can be ground in. The purpose of the ground-in process is to compensate for tolerances or irregularities on the surfaces of the first and second friction surfaces. After ground-in, a desired braking characteristic and a specified braking torque can be virtually guaranteed. The ground-in speed and the braking load can be varied during the process.

[0035] If the electromagnetic brake is a spring-applied brake and / or is intended to generate a holding force, it may be undesirable for the tribological system, i.e., the at least one first friction surface and / or the at least one second friction surface, to be worn or worn. It has been shown that, due to the special surface topography, particularly high holding forces can be generated by the thermal spraying process, because, for example, the surfaces involved in the tribological system form a tight fit.

[0036] Another aspect of the present invention relates to an electromechanical brake, in particular a permanent magnet brake or a spring-applied brake, with an excitation system comprising a magnet housing and an energizable coil, a restoring means, and an armature, wherein the armature—particularly when the coil is energized—is movable along a longitudinal axis against a restoring force of the restoring means. Furthermore, the electromechanical brake comprises a tribological system, wherein the tribological system has at least one first friction surface and at least one second friction surface. The at least one first friction surface and the at least one second friction surface can be brought into an operative connection or frictional contact to generate a braking force.The at least one first friction surface and / or the at least one second friction surface can be formed by a coating, in particular a hard metal coating, which is applied by means of a thermal spraying process.

[0037] When the coil is energized, the electromechanical brake releases. This moves the first friction surface, or at least one second friction surface that was previously in contact, away from each other. When the coil is de-energized, the restoring element acts on the armature in such a way that the tribological system generates a braking force.

[0038] Advantageously, the coating has a thickness between 5 and 100 µm, preferably between 10 and 30 µm. It is understood that the applied coating thickness can also be greater or less. Preferably, this thickness is achieved without post-processing of the first and / or second friction surface.

[0039] According to a preferred embodiment of the invention, the at least one friction surface and / or the at least one second friction surface has an average roughness depth Rz of between 20 and 100 µm, preferably between 8 and 35 µm. The average roughness depth can, of course, lie within a different range than the one mentioned above. Depending on the requirements, it can be greater or lesser. Preferably, a roughness depth Rz of between 20 and 100 µm, more preferably between 8 and 35 µm, is achieved without post-processing of the first and / or second friction surface.

[0040] According to a further advantageous embodiment of the invention, the hardness value of the first and / or second friction surface, provided it is formed by the coating, is 1400 HV 0.3. The hardness value can also be in a range around 1400 HV 0.3. For example, the hardness value can be in a range from 1000 HV 0.3 to 1800 HV 0.3. The hardness value refers to the specific measurement of the hardness of a material according to the Vickers hardness test. For example, 1400 stands for the hardness value, namely 1400 Vickers hardness. Furthermore, HV stands for the method used and 0.3 for the test force in kiloponds (kp). In the Vickers hardness test, a diamond-shaped pyramid is used as an indenter to determine the hardness of the material being tested. Preferably, a hardness value in the range of 1000 HV 0.3 to 1800 HV 0.3 can be achieved without post-processing of the first and / or second friction surface.It can be advantageous if the aforementioned hardness value is higher or lower.

[0041] According to a preferred embodiment of the invention, the coating is applied by means of a flame spraying process, preferably a high-speed flame spraying process.

[0042] Preferably, the coating is a hard metal coating, preferably based on tungsten carbide or chromium carbide. In flame spraying with, for example, tungsten carbide, a mixture of tungsten carbide and a binder is typically used. This mixture is melted and sprayed onto the workpiece to be coated, where it then cools rapidly and solidifies into a durable coating. Tungsten carbide coatings are characterized by their wear resistance, hardness, and high temperature resistance.

[0043] Advantageously, the restoring element includes at least one permanent magnet. The electromechanical brake can therefore be designed as a permanent magnet brake. The advantage of permanent magnet brakes over spring-applied brakes, for example, lies in their generally faster response time, which is beneficial for servo drives, particularly in robotics. Furthermore, the braking force of permanent magnet brakes is usually higher than that of spring-applied brakes. Permanent magnet brakes are also characterized by a more compact design and axial force generation in the closed field position.

[0044] The permanent magnet is advantageously designed as a neodymium-iron-boron magnet or a samarium-cobalt magnet.

[0045] Furthermore, it has proven advantageous if the magnet housing is ring-shaped.

[0046] Preferably, the magnet housing has an approximately U-shaped cross-section and can have an annular groove in which the coil can be arranged.

[0047] Furthermore, it is advantageous if the approximately U-shaped magnet housing has an outer pole and an inner pole, and if the at least one first friction surface or the at least one second friction surface is arranged on the inner pole and / or on the outer pole. The inner pole and / or the outer pole can each have a friction surface. The approximately U-shaped magnet housing has an outer leg, an inner leg, and a rear wall connecting the inner and outer legs, with the inner pole being arranged at the end of the inner leg and the outer pole at the end of the outer leg.

[0048] Preferably, the magnet housing comprises a flange, wherein the flange forms a free end of the inner or outer leg.

[0049] In an advantageous embodiment of the invention, at least one first friction surface is arranged on the armature. At least one second friction surface can be arranged on the magnet housing, preferably on the outer pole and / or on the inner pole.

[0050] During braking, the at least one first friction surface of the armature interacts with the at least one second friction surface of the outer pole and / or the inner pole. The at least one first friction surface and / or the at least one second friction surface can be ring-shaped and correspondingly shaped and / or arranged in relation to each other.

[0051] It should be noted here that the at least one second friction surface on the inner pole and / or the at least one second friction surface on the outer pole can also be formed by the coating. The coating can be applied to the magnet housing accordingly for this purpose.

[0052] According to a preferred embodiment, a first distance A1 between the at least one second friction surface of the inner pole and the at least one first friction surface of the armature can be different from a second distance A2 between the at least one second friction surface of the outer pole and the at least one first friction surface of the armature, i.e., A1 ≠ A2. In the simplest case, the second friction surfaces of the inner pole and the outer pole can be arranged offset along the longitudinal axis. It should be noted that the distance is measured parallel to the longitudinal axis and radially centered on the respective friction surface.

[0053] Preferably, the friction surface of the outer pole is positioned along the longitudinal axis above the friction surface of the inner pole, or vice versa. This design allows, for example, one of the friction surfaces on the inner or outer pole to be ground in to compensate for tolerances and / or accommodates deformation of the electromagnetic brake in the assembled state, e.g., in a servo motor application.

[0054] Advantageously, the at least one first friction surface and / or the at least one second friction surface of the tribological system is conical. Advantageously, the at least one first and / or the at least one second friction surface of the tribological system is conical, or the at least one first and / or the at least one second friction surface is arranged in at least one plane perpendicular to the longitudinal axis. The at least one friction surface and / or the at least one second friction surface can also be linear, such that the distance of a first and / or second friction surface to the anchor decreases continuously. The first friction surface or the second friction surface can also have any other desired shape.

[0055] In an advantageous embodiment of the invention, the restoring means comprises at least one spring.

[0056] Preferably, the at least one spring is arranged inside the magnet housing, preferably in a receptacle, with the spring pressing against the armature and thus pressing the at least one first friction surface and the at least one second friction surface against each other to generate the braking force.

[0057] Preferably, a friction disc is arranged between the armature and a flange, wherein the friction disc can be fixed between the armature and the flange by the spring force of at least one spring. The friction disc can have at least one first friction surface or at least one second friction surface on the side facing the armature and / or the flange. The at least one second friction surface or the at least one first friction surface can be arranged on the armature and / or on the flange.

[0058] According to a preferred embodiment, the friction disc can be torsionally rigidly connected to a driver which is connected to a motor shaft.

[0059] According to a particularly preferred embodiment of the invention, at least one first friction surface is arranged on the anchor, at least one second friction surface is arranged on the flange and / or at least one second friction surface is arranged on the friction disc.

[0060] The at least one first friction surface is preferably a continuous and more preferably ring- or circular surface, preferably formed by the coating. The first friction surface can be pre- and post-processed, thereby allowing a desired roughness and hardness to be achieved. Preferably, the first friction surface is formed on the anchor.

[0061] The at least one second friction surface is preferably a continuous and more preferably annular or circular surface, which preferably does not have a coating applied by thermal spraying, but consists of a ferromagnetic material, preferably a low-alloy steel. Preferably, the at least one second friction surface is formed by the outer pole and / or the inner pole. The second friction surface can also have the coating applied by thermal spraying, in particular the hard metal coating.

[0062] The coating, particularly the hard metal coating, is preferably applied using thermal spraying. This results in an increase in friction coefficients of 20 percent or more compared to inorganic materials. Furthermore, brake wear is reduced by half due to the increased hardness, and maximum braking energy is increased.

[0063] Two embodiments of the present invention are described in detail below with reference to the accompanying drawings. The drawings show: Fig. 1 a sectional view of a first embodiment of an electromechanical brake with a tribological system, wherein the electromechanical brake is designed as a permanent magnet brake, Fig. 2 a perspective view of the armature of the electromechanical brake according to Fig. 1, Fig. 3a a detailed representation of the tribological system according to Fig. 1, Fig. 3b a detailed presentation of a first further development of the tribological system, Fig. 3c a detailed representation of a second advanced development of the tribological system, Fig. 3D shows a detailed representation of a third developmental stage of the tribological system, and Fig. 4 a sectional view of a second embodiment of the electromechanical brake, wherein the electromechanical brake is designed as a spring pressure brake.

[0064] Identical or functionally equivalent parts or features are identified by the same reference numerals in the detailed description of the figures below. Likewise, not all identical or functionally equivalent parts or features in the figures are assigned a reference number.

[0065] Fig. Figure 1 shows an electromechanical brake 1, which is designed as a permanent magnet brake.

[0066] The electromechanical brake 1 comprises an excitation system 20 with an energizable coil 22, a restoring means 10, and an armature 40 movable on a longitudinal axis L, wherein the armature 40 is movable along a longitudinal axis L against a restoring force of the restoring means 10. Furthermore, the electromechanical brake comprises a tribological system 80, wherein the tribological system 80 has at least a first friction surface 81 and at least a second friction surface 82, which can interact to generate a braking force. The electromechanical brake 1 can also include a flange hub 65, which can establish a rotationally fixed connection with a motor shaft 5.

[0067] The excitation system 20, the anchor 40 and / or the flange hub 65 are preferably arranged rotationally symmetrically about the longitudinal axis L.

[0068] The flange hub 65 is preferably connected in a rotationally rigid manner to a motor shaft 5, which is driven, for example, by an electric motor (not shown). The motor shaft 5 can pass through the electromechanical brake 1, wherein the motor shaft 5 is also arranged rotationally symmetrically and preferably coaxially to the longitudinal axis L.

[0069] The excitation system 20 comprises a magnet housing 30 and the currentable coil 22.

[0070] The magnet housing 30 is preferably ring-shaped, similar to a pot magnet housing, and has a rotationally symmetrical opening 35 along the longitudinal axis L. The magnet housing 30 is soft magnetic and can preferably be made of a ferromagnetic material, in particular a low-alloy steel. The magnet housing 30 has an inner pole 61 and an outer pole 31, each of which can form one of the at least one second friction surface 82.

[0071] The magnet housing 30 also has an axial annular groove 32. Due to the axial annular groove 32, the pot-shaped magnet housing 30 has an approximately U-shaped cross-section and has an outer leg 36, a back wall 34 and an inner leg 33.

[0072] The back wall 34 connects one outer leg 36 with the inner leg 33 and the back wall 34, the outer leg 36 and / or the inner leg 33 are preferably formed in one piece.

[0073] A free end of the outer leg 36 forms the outer pole 31 and a free end of the flange 60 forms the inner pole 61.

[0074] The coil 22 can comprise a coil carrier, which, for example, as in the illustrated embodiment, is formed by a plastic housing 26.

[0075] The coil 22 is arranged in the magnet housing 30. More precisely, the coil 22 is arranged in the axial annular groove 32 of the magnet housing 30. For example, the coil can be pressed into the axial annular groove 32.

[0076] The plastic of the housing 26 electrically insulates the magnet housing 30 from the coil 22. The coil 22 consists of a conductor wire made of copper or another highly conductive material such as aluminum. An insulating layer surrounds the conductor wire, preventing short circuits between the contact points of the conductor wire sections when the coil is wound.

[0077] The coil 22 has electrical connections that are led out of the permanent magnet brake and supply the permanent magnet brake with energy.

[0078] The magnet housing 30 further includes a flange 60, which is arranged rotationally symmetrically around the longitudinal axis L and is made of a ferromagnetic material.

[0079] The flange 60 in the embodiment according to Fig. 1 forms the free end of the inner leg 33 and is therefore arranged on the side of the inner leg 33 facing away from the rear wall 34.

[0080] The flange 60 can project radially beyond the axial annular groove 32. The flange 60 is preferably positioned directly in front of the axial annular groove 32 of the magnet housing 30, so that the coil 22 cannot be removed from the axial annular groove 32. The flange 60 can be screwed to the rest of the magnet housing 30.

[0081] The inner pole 61 is formed on a radially outer surface 62 of the flange 60, wherein the inner pole 61 – as shown – can be arranged on a projection 64 formed in the longitudinal axis L, see also Fig. 3A.

[0082] The at least one second friction surface 82 is formed by the inner pole 61 and / or the outer pole 31.

[0083] The armature 40 is rotationally symmetrical and has the form of a circular disk with an opening 42 in its center. The armature 40 is arranged coaxially to the longitudinal axis L and is preferably made of a ferromagnetic material. Preferably, the armature 40 has approximately the same outer diameter as the magnet housing 30.

[0084] The anchor 40 has at least one first friction surface 81. The at least one first friction surface 81 is formed from a coating 83 applied to the anchor 40. The coating 83 is preferably a hard metal coating and is further preferably applied to the anchor 40 by means of a thermal spraying process.

[0085] The armature 40 is arranged on or in front of the magnet housing 30 along the longitudinal axis L, with the first friction surface 81 located on the side facing the magnet housing 30. When the coil 22 is energized, there is a working air gap between the armature 40 and the magnet housing 30.

[0086] The first friction surface 81 and the second friction surface 82 form the tribological system 80. In the closed state of the electromechanical brake 1, the first friction surface 81 and the second friction surface 82 come into frictional contact and contribute to the generation of the braking torque.

[0087] The coating 83 is a hard metal coating which is applied to the anchor 40, in particular preferably over a surface, by means of a thermal spraying process, in particular to an end face of the anchor 40.

[0088] The second friction surfaces 82, which are mostly arranged on the inner pole 61 and / or outer pole 31, can also be formed by a coating 83 applied to the magnet housing 30.

[0089] The coating 83 can be produced as follows: In a first process step, the substrate workpiece, i.e., in the exemplary embodiment, the armature 40 and / or magnet housing 30, is provided. Subsequently, the substrate workpiece can be prepared for the application of the coating by means of a cleaning and / or roughening process, for example, to remove contaminants and / or to activate the surface to be coated. The pretreatment can, for example, include pressure blasting, whereby either high-grade corundum or standard corundum F150 can be used as the blasting media.

[0090] The coating 83 is produced by a thermal flame spraying process, preferably a high-velocity oxygen fuel spraying (HVOF) process, for example with a tungsten carbide spray powder or a chromium carbide spray powder (CrC-NiCr) wherein the mass fraction of chromium carbide is 75% and the mass fraction of nickel-chromium is 25%. Thus, the coating 83 can, for example, be a tungsten carbide layer with a composition such as WC86 CoCr10-4 or WC-CrC-Ni. Preferably, the high-velocity flame spraying is carried out at, for example, MACH 3 or even up to MACH 16, whereby the coating 83 is applied with a layer thickness of 10-25 µm.

[0091] The coating exhibits - preferably without post-processing - an average roughness depth Rz between 8 and 25 µm.

[0092] However, after the application of a coating 83, the coating 83 can be reworked by means of a grinding and / or blasting process.

[0093] After cleaning, if necessary, the electromechanical brake 1 can be installed and the tribological system 80 can be broken in. The breaking in is carried out with the electromechanical brake 1 de-energized, i.e., in the closed position. The breaking in process can comprise one or more braking cycles.

[0094] The flange hub 65 and the anchor 40 are in Fig. Figure 2 shows the annular first friction surface 81 formed by the coating 83, which is shown in a checkered pattern. The flange hub 65 has a hub section 66 and a flange-shaped projecting flange section 67, which is arranged parallel to the armature 40. The armature 40 is axially movable but torsionally rigidly connected to the flange hub 65 via one or more segment springs 44 and drivers 70. The segment springs 44 allow movement of the armature 40 in the longitudinal axis L relative to the flange hub 65 and transmit the braking torque from the armature 40 to the flange hub 65 or to the motor shaft 5.

[0095] The restoring element 10 is arranged between the inner leg 33 and the outer leg 36, or between the inner pole 61 and the outer pole 31 of the magnet housing 30. The restoring element 10 is a radially magnetized permanent magnet 12, which is preferably arranged symmetrically about the longitudinal axis L. The permanent magnet can also consist of individual segments. These are preferably arranged equidistant from one another.

[0096] The permanent magnets 12 are preferably designed as neodymium-iron-boron magnets or samarium-cobalt magnets. These are characterized by a strong and stable magnetization, which results in a high braking force.

[0097] In the unenergized state of coil 22 (not shown), the permanent magnet 12 causes the reluctance force to press the armature 40 against the magnet housing 30 and the at least one first friction surface 81 against the at least one second friction surface 82. The reluctance force moves the armature against the spring force of the segment springs 44.

[0098] To release the electromechanical brake 1, an electromagnetic field is generated by applying a voltage to the coil 22. The magnetic flux induced by the coil 22 at poles 31, 61 largely cancels out the magnetic flux of the permanent magnets 12. The superposition of the magnetic field of the coil and the magnetic field of the permanent magnets 12 cancels the reluctance force at poles 31, 61, and the armature 40 can be retracted by the segment springs 44. Between the armature 40 and the magnet housing, as shown in Fig. As shown in 1, the working air gap is released.

[0099] Fig. Figure 3A shows a detailed representation of the electromechanical brake 1 designed as a permanent magnet brake according to Fig. 1. It is evident that the first friction surface 81 on the armature 40 is arranged in a plane perpendicular to the longitudinal axis L. The second friction surface 82 of the outer pole 31 is arranged along the longitudinal axis L at a first distance A1 from the first friction surface 81, and the second friction surface 82 of the inner pole 61 is arranged at a second distance A2 from the first friction surface 81. The distance A1 in the illustrated embodiment is smaller than the distance A2. Thus, A1 < A2.

[0100] The flange 60 has a projection 64 on the side facing the armature 40, which forms the inner pole 61. The second friction surface 82 of the inner pole 61 and the second friction surface 82 of the outer pole 31 are each arranged in a plane perpendicular to the longitudinal axis L, the planes being parallel and spaced apart from each other.

[0101] Fig. Figure 3B shows a detailed representation of the electromechanical brake 1, designed as a permanent magnet brake, according to a first embodiment, wherein the first distance A1 and the second distance A2 are identical, i.e., A1 = A2. Otherwise, this embodiment is analogous to the previously described embodiment.

[0102] Fig. Figure 3C shows a detailed representation of the electromechanical brake 1, designed as a permanent magnet brake, according to a second embodiment, wherein the second friction surface 82, or the inner pole 61 and the outer pole 31, are conically shaped. The second friction surface 82, or the inner pole 61 and the outer pole 31, are inclined outwards. Furthermore, the Fig. It can be seen from 3c that the second distance A2 is smaller than the first distance A1, i.e., A2 < A1. Furthermore, this refinement is analogous to the previously described embodiment and its further development.

[0103] Fig. Figure 3D shows a detailed representation of the electromechanical brake 1, designed as a permanent magnet brake, according to a third embodiment, wherein the inner pole 61, or the second friction surface 82 on the inner pole 61, is conically shaped and inclined inwards. The second friction surface 82 on the outer pole 31 is parallel to the first friction surface 81 on the armature 40.

[0104] Furthermore, the Fig. It can be deduced from 3d that the second distance A2 is smaller than the first distance A1, i.e., A2 < A1.

[0105] Furthermore, this advanced training is analogous to the previously described example and its further training.

[0106] Fig. Figure 4 shows a second embodiment of an electromechanical brake 1, wherein the electromechanical brake 1 is a spring-applied brake. For the sake of simplicity, the differences between the two embodiments will only be briefly discussed below.

[0107] The electromechanical brake 1 comprises the excitation system 20 and the armature 40, which is movable along the longitudinal axis L. Unlike the first embodiment, the tribological system 80 is not formed by the magnet housing 30 and the armature 40, but rather a friction disc 85 and a flange 88 are arranged on the side of the armature 40 facing away from the magnet housing 30. The flange 88 is rigidly connected to the magnet housing 30. The flange 88 can also be rigidly connected to the motor end shield.

[0108] The friction disc 85 can rotate about the longitudinal axis L and is preferably coupled to the motor shaft 5 in a rotationally fixed manner, for example by means of a driver 70.

[0109] The restoring means of the electromechanical brake 1 according to Fig. 4 are several springs 14 arranged around the circumference about the longitudinal axis l, which are supported in recesses of the magnet housing 30 on one side and on the armature 40 on the other. The springs 14 can press the armature 40 against the friction disc 85 and the friction disc 85 against the flange 88.

[0110] In this embodiment, the tribological system 80 is also formed by at least one first friction surface 81 and at least one second friction surface 82, which can be brought into effective contact to generate a braking force.

[0111] The friction disc 85 has at least on the side facing the flange 88 a first friction surface 81, wherein the first friction surface 81 is formed by the coating 83.

[0112] The flange 88 has a second friction surface 82 on the side facing the friction disc 85. The second friction surface 82 can also be formed by the coating 83.

[0113] It is also possible that the friction disc 85 has a further first friction surface 81 on the side facing the anchor 40, which is arranged with a further second friction surface 82 on the side of the anchor 40 facing the friction disc 85. The further first friction surface 81 and / or the further second friction surface 82 can also be formed by a corresponding coating 83. The respective coating 83 can be produced as described above in connection with the first embodiment, wherein the friction disc 85 and / or the flange 88 and / or the anchor 40 are the carrier workpiece.

[0114] In the unenergized state of coil 22 according to Fig. The springs 14 press against the armature 40, and the armature 40 is pressed against the friction disc 85. The working air gap between the armature 40 and the magnet housing 30 is opened.

[0115] The anchor 40 and the axially immovable flange 88 clamp the friction disc 85 between them, and the tribological system 80 described above generates a braking force.

[0116] When coil 22 is energized, the electromechanical brake 1 is released, and a magnetic force builds up which counteracts and exceeds the force of the springs 14. The armature 40 is moved away from the friction disc 85 along its longitudinal axis L, allowing the friction disc 85 to rotate freely. Reference symbol list 1 brake 5 Motor shaft 10 reserve funds 12 permanent magnets 14 springs 20 Pathogen system 22 coil 26 plastic housings 30 magnetic housings 31 Outer pole 32 Ring groove 33 inner thigh 34 Back panel 35 Breakthrough 36 outer thigh 40 anchors 42 Breakthrough 44-segment spring 64 lead 60 flange 61 Inner pole 62 Outdoor area 65 Flange hub 66 Hub section 67 Flange section 70 drivers 80 tribological system 81 first friction surface 82 second friction surface 83 Coating 85 friction disc 88 flange A1 first distance A2 second distance L Longitudinal axis QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 10 91 25 A1

[0004]

Claims

[1] Method for manufacturing an electromechanical brake (1) comprising an excitation system (20), an armature (40), a restoring means (10) and a tribological system (80), - wherein the excitation system (20) comprises a magnet housing (30) and an energizable coil (22), - wherein the anchor (40) is movable along a longitudinal axis (L) against a restoring force of the restoring means (10), and - wherein the tribological system (80) comprises at least one first friction surface (81) and at least one second friction surface (82), wherein the at least one first friction surface (81) and the at least one second friction surface (82) can be brought into operative contact to generate a braking force, wherein the method comprises the following process steps: - Creating at least one first friction surface (81) and / or at least one second friction surface (82) by applying a coating (83) using a thermal spraying process. [2] Method according to claim 1, characterized by , that prior to the application of the coating (83) preparation is carried out by means of a cleaning and / or roughening process. [3] Method according to one of claims 1 or 2, characterized by that the thermal spraying process is a flame spraying process, preferably a high-speed flame spraying process. [4] Method according to any one of claims 1 to 3, characterized by , that the at least first friction surface (81) and / or the at least one second friction surface (82) is reworked after the application of a coating (83), preferably by means of a grinding and / or blasting process. [5] Method according to any one of claims 1 to 4, characterized by , that the tribological system (80) is ground in when the electromechanical brake (1) is assembled. [6] Electromechanical brake (1), in particular a permanent magnet brake or a spring pressure brake, preferably manufactured by a method according to one of the preceding claims, comprising: - an excitation system (20) comprising a magnet housing (30) and a coil (22), - a reserve (10), - an anchor (40), - wherein the anchor (40) is movable along a longitudinal axis (L) against a restoring force of the restoring means (10), - a tribological system (80), - wherein the tribological system (80) has at least one first friction surface (81) and at least one second friction surface (82), and - wherein the at least one first and the at least one second friction surface (81, 82) can be brought into an effective connection to generate a braking force, characterized by , that - which at least one first friction surface (81) and / or at least one second friction surface (82) are formed by a coating (83) applied by means of a thermal spraying process. [7] Electromechanical brake (1) according to claim 6, characterized by , that the coating (83) has a thickness between 5 to 100 µm, preferably between 10 to 30 µm. [8] Electromechanical brake (1) according to claim 6 or 7, characterized by , that the at least one first and / or the at least one second friction surface (81, 82) has an average roughness depth Rz between 8 and 35 µm. [9] Electromechanical brake (1) according to any one of claims 6 to 8, characterized by , that the at least one first friction surface (81), and / or the at least one second friction surface (82) has a hardness value of approximately 1400 HV 0.3 as measured by the Vickers hardness test. [10] Electromechanical brake (1) according to any one of claims 6 to 9, characterized by, that the coating (83) is applied by means of a flame spraying process, preferably a high-speed flame spraying process. [11] Electromechanical brake (1) according to any one of claims 6 to 10, characterized by that the coating (83) is a hard metal coating, preferably based on tungsten carbide or chromium carbide. [12] Electromechanical brake (1) according to any one of claims 6 to 11, characterized by that the restoring means (10) comprises at least one permanent magnet (12). [13] Electromechanical brake (1) according to any one of claims 6 to 12, characterized by , that the magnet housing (30) is approximately U-shaped in cross-section. [14] Electromechanical brake (1) according to any one of claims 6 to 13, characterized by , that the magnet housing (30) has an annular groove (32) in which the coil (22) is arranged. [15] Electromechanical brake (1) according to claim 14, characterized by, that the magnet housing (30) comprises a flange (60), wherein the flange (60) preferably partially closes the annular groove (32). [16] Electromechanical brake (1) according to any one of claims 6 to 15, characterized by , that the armature (40) has at least one first friction surface (81) and / or that the magnet housing (30) has at least one second friction surface (82). [17] Electromechanical brake (1) according to any one of claims 6 to 16, characterized by , that the approximately U-shaped magnet housing (30) has an outer pole (31) and an inner pole (61) and that the at least one second friction surface (82) is arranged on the inner pole (61) and the outer pole (31). [18] Electromechanical brake (1) according to any one of claims 6 to 17, characterized by, that a distance (A1) between the second friction surface (82) at the inner pole (61) and the first friction surface (81) of the armature (40) is not equal to a distance (A2) between the second friction surface (82) at the outer pole (31) and the first friction surface (81) of the armature (40), i.e. A1 ≠ A2. [19] Electromechanical brake (1) according to any one of claims 6 to 18, characterized by , that the at least one first friction surface (81) and / or the at least one second friction surface (82) of the tribological system are conically shaped or that the at least one first friction surface (81) and / or the at least one second friction surface (82) are arranged in at least one plane perpendicular to the longitudinal axis (L). [20] Electromechanical brake (1) according to any one of claims 6 to 19, characterized by that the restoring means (10) is at least a spring (14). [21] Electromechanical brake (1) according to claim 20, characterized by, that a friction disc (85) is provided which can be clamped by the spring (14) between the anchor (40) and a flange (88) to generate the braking force. [22] Electromechanical brake (1) according to claim 20 or 21, characterized by , that at least one first friction surface (81) is arranged on the anchor (40) and at least one second friction surface (82) is arranged on the flange (88) and / or at least one second friction surface (82) is arranged on the friction disc (85).

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