Abstract: The method and a device to measure the repeatable and non-repeatable runouts of a rotating component of a spindle motor with the aid of at least one probe measuring changes in the distance between the probe and the rotating component depending on the angle of rotation. The probe records a first test signal in a first test cycle from which a signal defining the RRO is determined and stored. In a second test cycle, a command signal proportional to the amplitude and phase of the RRO signal is generated and fed to an electromechanical actuator supporting the probe. Depending on the command signal derived from the first test signal, the actuator changes the distance between the probe and the outer perimeter of the rotating component, thus compensating the runout defined by the RRO signal, while the probe records a second test signal defining the NRRO.

Abstract: A rolling bearing and a rod end bearing are provided with a tilt mechanism and a rotary mechanism that are mutually independent. The tilt mechanism has a non-lubricated type spherical sliding bearing structure. The rotary mechanism has a rolling bearing structure which may or may not be sealed. By means of the non-lubricated type spherical sliding bearing structure, a tilt of the shaft center is made possible, and by means of a sealed rolling bearing structure, problems such as a lubrication oil leak are avoided, and carrying out high speed rotation and continuous rotation become possible. Because the sealed rolling bearing structure of the rotary mechanism does not call for a shaft center tilt function at all, the material of the seal can be chosen such that it emphasizes sliding resistance and high durability.

Abstract: A hydrodynamic bearing system, having a bearing sleeve and a shaft inserted into an inner cylindrical bore of the bearing sleeve. A bearing gap is formed between the shaft and the bearing sleeve, the bearing gap being filled with a lubricating oil. A shield encloses the bearing sleeve. The shield is secured within a recess formed at the top surface of the bearing sleeve at a position distanced from the bearing gap. The shield is pressed against a sharp edge of the recess by a metal ring placed into the recess.

Abstract: A stator stack and stator jig assembly provide a consistent amount of slack in stator coil wires without increasing the complexity of coil-winding machines or adding production steps, and prevent crossing of the stator coil wires in the slack areas. A stator stack having magnetic pole teeth is mounted in a stator installation jig, and the ends of slack forming plates having grooves are made to project above the top surface of the stator stack to thrust stator coil wires upwardly. The coil-winding machine winds stator coil wires around the magnetic pole teeth, and after the stator coil wires are wound, the ends of the stator coil wires are passed through grooves in the ends of the plates to output pins. The coil-winding machine wraps the ends of the stator coil wires around the output pins. On removing the stator from the stator installation jig, the parts of the stator coil wires which where thrust upward become slack areas.

Abstract: An image forming apparatus having a belt supporting frame for supporting an intermediate transfer belt is provided. The intermediate transfer belt is a multi-layered structure composed of at least an elastic layer on a substrate layer. When a percentage difference of a stretched length of an outer circumference of the intermediate transfer belt to an inner circumference thereof at a position of contact to the driving roller is A % and a percent difference of a length of stretched side of the belt driven and stretched by the driving roller to a length of non-stretched opposite side of the belt is B %, the intermediate transfer belt is configured so that ranges of A and A+B fall simultaneously into inequalities of 1<A<6 and 3<A+B<10.

Abstract: A hydrodynamic bearing system, particularly for the rotary bearing of spindle motors to power hard disk drives. The bearing system includes a bearing sleeve, a shaft accommodated in an opening in the bearing sleeve and at least one radial bearing section provided between the bearing sleeve and the shaft with the aid of which the shaft and the bearing sleeve are supported rotatably in relation to each other. A bearing gap is formed between the shaft and the bearing sleeve and is filled with a liquid lubricant. A lubricant reservoir and equalizing volume independent from the design of the bearing arrangement is provided in that at least one duct is formed in the bearing sleeve that extends from an outer section of the bearing sleeve to the bearing gap and that is at least partially filled with lubricant.

Abstract: A pivot assembly for use in a hard disk drive, in which ball bearings are placed at both ends of a shaft, and a spacer is disposed between outer rings of the ball bearings. The spacer is fixed to the outer rings by laser welding.

Abstract: A hydrodynamic bearing system, having a bearing sleeve and a shaft inserted into an inner cylindrical bore of the bearing sleeve. A bearing gap is formed between the shaft and the bearing sleeve, the bearing gap being filled with a lubricating oil. A shield encloses the bearing sleeve. The shield is secured at to an end surface of the bearing sleeve at a position on the end surface that is distanced from the bearing gap. The shield does not contact the lubricating oil.

Abstract: The present invention provides a bearing comprised of a hydrodynamic bearing and a pivot bearing, which can be used with a spindle motor. It also provides a spindle motor utilizing a hydrodynamic bearing and a pivot bearing.

Abstract: A stepping motor stator stack and rotor stack finishing method whereby the burrs remaining on the small tooth surfaces of the stacks can be eliminated and prevented from lodging in the spaces between laminations of a plurality of stacked steel plates, without causing dulling of these small teeth. After abrasive finishing is carried out, a high pressure liquid jet spray nozzle is introduced into the central cylindrical cavity of a stator stack, and while the nozzle is moved along the central axis of the central cylindrical cavity and rotated relatively centered on the central axis of the central cylindrical cavity, the high pressure liquid jet is sprayed from the jet orifices striking the small tooth surfaces of the stator stack facing the central cylindrical cavity so as to remove the burrs remaining on the small tooth surfaces.

Abstract: A hydrodynamic bearing for use in a spindle motor, having a shaft, a bearing sleeve encompassing the shaft with a small radial space, and a skewback at one end face of the bearing sleeve which is fixedly connected to the bearing sleeve. The shaft features a thrust plate or a conical or cone-like extension at its end face which faces the skewback. The diameter of the conical extension increases in the direction of the end face of the shaft. A bearing gap formed between the shaft and the bearing sleeve is filled with a bearing fluid. Dynamic pressure generating grooves are provided on one of the outer surface of the shaft and the inner surface of the bearing sleeve to generate an excess pressure in the bearing fluid.

Abstract: A slack-forming mechanism for stator coils that is able to impart slack of appropriate size to the stator coil without imposing an excessively heavy burden on the coiling machine. The slack-forming mechanism includes a coiling machine attachment jig having a protruding member that passes through a clearance formed between a stator body and connector, and has a top edge positioned higher than a clearance pass-through part of a stator coil. As it is possible to form slack in the stator coil without changing the configuration of the coiling machine, deficiencies in prior art slack-forming mechanisms are overcome such as the difficulty of maintaining uniform slack amounts, and unreliability. Moreover, since design-related restrictions are few, an adequately large slack is imparted to the stator coil to adequately suppress breakage of the stator coil induced by temperature change.

Abstract: An axial flow fan motor having an impeller molded integrally with a shaft from a synthetic resin. The shaft is easily assembled with a bearing arrangement by being brought into tight contact with the inner ring of the bearing arrangement and is reliably fixed thereto in the elastic region of the shaft. A through hole is formed in the shaft along its central axis. After the shaft is fit into the inner ring of the bearing arrangement, a metal pin is pressed into the axial through hole. Because the pin is pressed in, the shaft is elastically expanded and brought into tight contact with the inner ring and fixed thereto in the elastic region of the shaft. Furthermore, the distal end portion of the shaft elastically outwardly expands and is pressed against the end surface of the inner ring, thereby preventing the bearing arrangement from coming off the shaft.

Abstract: An image forming apparatus having a belt supporting frame for supporting an intermediate transfer belt is provided. The belt supporting frame may be separable into a plurality of unit bodies. Separation of the plurality of unit bodies may be regulated by a bending mechanism, wherein the plurality of unit bodies may be separable in a direction orthogonal to the transporting direction of the intermediate transfer belt. The plurality of unit bodies may also be regulated by a variable length mechanism capable of expanding and contracting the plurality of unit bodies in a direction parallel to the transporting direction of the intermediate transfer belt. Separation of the belt supporting frame into a plurality of unit bodies may allow for a circumference area smaller than that of the intermediate transfer belt to be formed so as to provide for simplified mounting, removal and maintenance of the intermediate transfer belt on the belt supporting frame.

Abstract: A spindle motor for use in hard disk drives having a base plate, a stationary shaft, a rotationally driven rotor, and a bearing system rotationally supporting the rotationally driven rotor. The shaft is fixedly mounted on the base plate. The base plate includes a drilled hole for insertion of a portion of the shaft such that this shaft's portion and the inner surface of the hole define a joint length l, when this portion is pressed into the drilled hole. The shaft has at least one notch located along the shaft's circumference and interrupting the joint length l.

Abstract: An impact printing apparatus is also disclosed with printing pin actuation timing correction dependent upon scanning speed or platen shape, striking duration timing dependent upon scanning rate, or printing pin actuation timing dependent upon stored shift amounts.