# US 8,464,847 B2 · Friction brake having a contact surface provided between two brake elements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,847 B2 - Document ID: US8464847B2 - Status: Granted - Kind: B2 - Application number: 12/526,186 - Filed: 2008-02-06 - Published: 2009-12-31 - Granted: 2013-06-18 - Earliest claimed: 2007-02-07 - Assignees: Siemens Aktiengesellschaft - Applicants: Marcus Ziegler - Inventors: Marcus Ziegler - Web page: https://patentgrep.com/patent/US8464847B2 ## CPC - H02K 7/1025: {using axial electromagnets with generally annular air gap} - F16D 2055/0058: {Fully lined, i.e. braking surface extending over the entire disc circumference} - F16D 2055/0095: {Plural rotors with different properties, e.g. to influence working conditions like wear or temperature} - F16D 2065/026: {characterised by a particular outline shape of the braking member, e.g. footprint of friction lining} - F16D 2069/004: {Profiled friction surfaces, e.g. grooves, dimples} - F16D 2121/22: for releasing a normally applied brake - F16D 2129/065: {Permanent magnets} - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract The invention relates to a friction brake which can be used for a shaft and a bearing part that can be rotated in relation to each other about a rotational axis (3). The friction brake comprises two brake elements: the first brake element has a first friction surface (24) and has to be mechanically connected to the bearing part, and the second brake element has a second friction surface (25) and has to be mechanically connected to the shaft. The connectible and disconnectable dynamic effect of an actuation mechanism forces the two brake elements against each other during a braking action or stop in such a manner that the two friction surfaces (24, 25) rest one on the other and contact each other in the area of a contact surface (29, 30). The contact surface (29, 30) covers only a part of every friction surface (24, 25) at any point in time during a braking action or stop. The relative position of the contact surface (29, 30) in relation to any of the two friction surfaces (24, 25) changes during a braking action. ## Claims ### Claim 1 A friction brake for a shaft and a mounting part which are rotatable in relation to one another about a rotational axis and are components of an electrical drive, wherein the friction brake is permanent magnetically excitable, said friction brake comprising: a first brake element having a first friction surface and mechanically connected to the mounting part, said friction surface forming a magnetic pole; a second brake element having a second friction surface and mechanically connected to the shaft, said first and second brake elements being magnetically attracted to one another; and an electromagnetically actuatable activation mechanism applying a force to press the first and second brake elements against one another during a braking process or stopping process in such a way that the first and second friction surfaces bear against one another and contact in a region of a contact surface, with a magnetic flux flowing through said contact surface, wherein the first and second friction surfaces are formed by axially protruding webs and are configured in such a way that the contact surface engages with only a part of each of the first and second friction surfaces at any point in time during a braking process or stopping process, and a relative position of the contact surface with respect to each of the first and second friction surfaces changes during a braking process. ### Claim 2 (depends on 1) The friction brake of claim 1, wherein at least one of the first and second friction surfaces is composed of a plurality of partial friction surfaces which are separated from one another. ### Claim 3 (depends on 1) The friction brake of claim 1, wherein one of the first and second friction surfaces is composed of a plurality of strip-shaped partial friction surfaces which are distributed uniformly in a circumferential direction which is specified with respect to the rotational axis. ### Claim 4 (depends on 3) The friction brake of claim 3, wherein the strip-shaped partial friction surfaces are each directed radially outward. ### Claim 5 (depends on 3) The friction brake of claim 3, wherein the strip-shaped partial friction surfaces are each inclined with respect to a radial direction. ### Claim 6 (depends on 3) The friction brake of claim 3, wherein the strip-shaped partial friction surfaces are each embodied in a curved fashion. ### Claim 7 (depends on 3) The friction brake of claim 3, wherein the strip-shaped partial friction surfaces are each embodied in the form of annular segments. ### Claim 8 (depends on 1) The friction brake of claim 1, wherein at least one of the first and second friction surfaces has a strip shape which is nonannular and enclosed. ### Claim 9 (depends on 8) The friction brake of claim 8, wherein the strip shape is periodic in a circumferential direction. ### Claim 10 (depends on 8) The friction brake of claim 8, wherein the nonannular friction surfaces are produced by superimposing a sine function on a circular function. ### Claim 11 (depends on 1) The friction brake of claim 1, wherein the first and second friction surfaces each have a strip shape which is nonannular, enclosed and periodic in the circumferential direction, wherein a tangential periodicity of the first friction surface differs from a tangential periodicity of the second friction surface. ### Claim 12 (depends on 1) The friction brake of claim 1, wherein each of the two friction surfaces is embodied in a strip shape, and a strip width of the first friction surface differs from a strip width of the second friction surface.