# US 6,293,705 B1 · Annular gimbal assembly suitable for disc drive spindle bearings and method of making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,293,705 B1 - Document ID: US6293705B1 - Status: Granted - Kind: B1 - Application number: 09/494,752 - Filed: 2000-01-31 - Granted: 2001-09-25 - Earliest claimed: 1999-12-03 - Assignees: Seagate Technology LLC - Inventors: John William Elsing; David John Jennings - Web page: https://patentgrep.com/patent/US6293705B1 ## CPC - H02K 5/1735: {radially supporting the rotary shaft at only one end of the rotor (H02K5/1737 takes precedence)} - F16C 35/077: between housing and outer race ring - G11B 19/2009: {Turntables, hubs and motors for disk drives; Mounting of motors in the drive (means for clamping of disk to turntable G11B17/022 and subgroups)} - F16C 19/54: Systems consisting of a plurality of bearings with rolling friction (spindle bearings F16C35/08) - F16C 2370/12: Hard disk drives or the like - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract According to the present invention spindle bearings are assembled with at least one annular gimbal to compensate for undesired components of bearing compression force. Specific devices and methods are directed to compensating for either (a) operational force variations such as those caused by temperature variation or (b) assembly-related force variations such as those caused by misalignment. ## Claims ### Claim 1 A spindle bearing having an axis of rotation, comprising: a first set of balls positioned for movement along a first circle about the axis; a second set of balls positioned for movement along a second circle about the axis; a first member configured for rolling engagement with the first set of balls; a second member configured for rolling engagement with the second set of balls; an annular gimbal operatively coupled between the first and second members and able to bend so that the first member moves axially with respect to the second member; and a third member configured for rolling engagement with both sets of balls so that the third member rotates with respect to the first and second members. ### Claim 2 (depends on 1) The spindle bearing of claim 1 in which each ball of the first set has an axis of compression forming an angle with the axis of rotation that is less than about 80 degrees. ### Claim 3 (depends on 1) The spindle bearing of claim 1 in which each ball of the first set has an axis of compression, in which the gimbal has a reference line along each radial half plane, the reference line intersecting the axis of rotation at an acute angle greater than 45 degrees, the reference line forming a compression transfer angle less than about 25 degrees. ### Claim 4 (depends on 1) The spindle bearing of claim 1 in which the gimbal has an average width and an average thickness, the width being at least twice as large as the width. ### Claim 5 (depends on 1) The spindle bearing of claim 1 in which the gimbal has an average width and an average thickness, the width being at most ten times as large as the thickness. ### Claim 6 (depends on 1) The spindle bearing of claim 1 in which the gimbal has a minimum thickness that is less than the diameter of the balls of the first set. ### Claim 7 (depends on 1) The spindle bearing of claim 1 in which the balls of the first set are made of a ceramic. ### Claim 8 (depends on 1) The spindle bearing of claim 1 in which the annular gimbal has a major surface that is substantially perpendicular to the axis. ### Claim 9 (depends on 1) The spindle bearing of claim 1 in which the first member has a modulus of elasticity, and in which each ball of the first set has a modulus of elasticity that is greater than the first member's modulus of elasticity. ### Claim 10 (depends on 1) The spindle bearing of claim 1 in which the first member and the first set each have a coefficient of thermal expansion, and in which the coefficient of the first member is greater than the coefficient of the first set. ### Claim 11 (depends on 1) The spindle bearing of claim 1 in which the gimbal is made by forming at least one annular slot about the first member. ### Claim 12 (depends on 1) A disc drive tolerant of temperature variation comprising: the spindle bearing of claim 1; and a plurality of recording discs rigidly supported by a selected one of the members. ### Claim 13 (depends on 1) The spindle bearing of claim 1 in which the gimbal is thicker than about 0.4 millimeters. ### Claim 14 A disc drive comprising: a plurality of discs mounted on a spindle bearing; and means for compensating for temperature-induced ball bearing preload force variation in the spindle bearing.