Abstract: A small d.c. motor which includes a commutator including a plurality of commutator segments, a resilient metal brush kept in contact with the commutator segments, the commutator segments being coated with a layer of a lubricating fluid.

Abstract: The disposable intra-luminal ultrasonic instrument for the examination and/or treatment of blood vessels and similar lumina has a small transverse cross-section. The instrument includes a catheter comprising a body and a tip having a distal end and a distal portion adapted to be introduced into a lumen and a proximal portion. The catheter has a diameter no greater than 3 millimeters, a rotatable member in the tip, a micro motor in the tip and coupled to the rotatable member for rotating the rotatable member at a selected rpm, the motor having flat stator coils mounted on a flexible circuit board, and means for generating and supplying sound waves to the rotatable member.

Abstract: A door operator for a reversibly operable door, such as a garage door, includes a frame and a carriage movably mounted on the frame and attached to a door for moving the door between open and closed positions. A flexible drive member, such as an endless chain, extends on the frame and is capable of moving the carriage. A drive train is on the frame connected for moving the flexible drive member. A motor housing is mounted on the frame within the motor housing and connected to the drive train. The motor has a shaft extending from the motor housing and engaging the drive train. A bearing assembly that includes metal thrust bearings is on the shaft adjacent to the motor. The metal thrust bearing assembly increases the performance of the electric motor, and thus provides a more powerful motor without changing to a larger motor or otherwise modifying the motor design. The motor is mounted on the frame so as to allow the shaft freely to move axially relative to the motor to permit the shaft to self-align.

Abstract: A choke-coil fixture for miniature motors of a type having choke coils housed in recesses formed in an end bell closing an end of a motor housing, characterized in that choke-coil housing recesses are formed in such a manner as to lock ends of the choke coils when the choke coils are inserted into the recesses in the longitudinal direction, terminals having flat portions for pushing the other ends of the choke coils at portions electrically connecting the lead ends of the choke coils, and engaging portions for locking to the end bell is disclosed. The terminals for miniature motors can have positioning portions for positioning the terminals with respect to the lead ends of the choke coils, and cylindrical portions for engaging with the connecting power-feeding connecting pins; the cylindrical portion adapted to be flexible in size by being plastically deformed.

Abstract: An electric wiper motor, which comprises an armature housed in a motor casing, reduction gears housed in a gear casing coupled with the motor casing, an autostop mechanism for stopping a wiper blade at the predetermined position always, a cover member for covering an aperture of the gear casing, motor terminals having ends attached with brushes, and plural conductive plates disposed to the cover member in one body and forming an internal circuit for supplying an electric current to the armature through the autostop mechanism by connecting between an external circuit and the motor terminal or the autostop mechanism. According to this invention, it is easy to assemble the electric wiper motor with the autostop mechanism, and possible to improve the productivity.

Abstract: An axial flux electromagnetic micromotor is described. The micromotor has a stator, a rotor which is pivotally mounted in relation to the stator about an axis of rotation, the rotor having at least one pair of magnetic poles producing in an air gap a magnetic field substantially parallel to the axis of rotation and at least one substantially planar coil situated in the air gap in such a way as to intercept a flux created by the field, this micromotor having an air gap that is solely delimited by the rotor. The micromotor can be used to drive a mechanism.

Abstract: Micromechanical devices are formed on a substrate using a sacrificial layer deep X-ray lithography process to produce a rotating microrotor which is driven magnetically. The rotor typically has a diameter of a few hundred microns or less and is formed as a free structure which is assembled onto a hub formed on a substrate. Stator pole pieces are formed on the substrate of a ferromagnetic material surrounding the rotor, and are alThis invention was made with U.S. government support awarded by the National Science Foundationn (NSF), Grant #EET-88-15285. The U.S. government has certain rights in this invention.

Abstract: A field magnet for miniature motors of a type having a stator comprising a field magnet fixedly fitted to a motor housing, an end plate fitted to an open end of the motor housing; an a rotor comprising a rotor winding wound on a rotor core; electric current being fed to the rotor winding via a commutator making sliding contact with current feeding brushes that are held by brush holders fixedly fitted to the end plate; in which cogging during motor rotation is reduced to make motor rotation smooth by forming a magnet that has at the magnetic poles thereof higher maximum magnetic energy product than any other regions.

Abstract: The invention concerns an electromagnetic micromotor. Such micromotor includes a rotor constituted by a permanent magnet (52) partially embedded in an overmolding (54) formed from plastic material and which is provided with coupling means to a driven mechanism, a cage (60) including a bottom and a cover and intended to be engaged in the interior of a stator while the rotor is mounted for free rotation in the cage, and rotation guide means for the rotor (50) in the cage (60), such micromotor being characterized in that the rotation guide means are constituted, on the one hand, by two housings (74, 76) coaxially arranged in the overmolding (54), and on the other hand, by two spindles (78, 80) respectively integral with the bottom and the cover of the cage and intended to be accommodated respectively in one of these housings. Such micromotor is intended to equip timepiece movements of very small dimensions, for instance for ladies' watches.

Abstract: A miniature electric motor having a stator composed of a strip of rubber magnet having a varying width. The stator strip has; polarized regions of wide width, non-polarized regions of narrow width, and regions which bridge said polarized regions having a continuously varying width. The periphery of the polarized and non-polarized regions of the stator strip contains indents and protrusions to improve the cogging characteristics of the motor.

Abstract: The micromotor comprises a rotor rotatably mounted on a stator having copolanar electrodes for setting up an electric field between the stator and the rotor. To increase the useful torque that can be supplied by the motor, the rotor includes a peripheral ring disposed opposite the electrodes and which is connected to a hub by arms that enable the ring easily to tilt in response to the electric field set up by the electrodes.

Abstract: An electrostatically operated micromotor is described that includes a rotor having first and second major surfaces, an axis of symmetry, and conductive portions. First and second annular, segmented torque stators are disposed adjacent the first and second major surfaces of the rotor and a bearing tethers the rotor to a support surface. Circuitry connects to each electrode of each torque stator for applying phased signals that induce a rotational force in the rotor. Such phased signals applied to electrodes of the first torque stator differ in potential from phased signals applied to electrodes of the second torque stator, so as to electrostatically balance the rotor, whereby net forces exerted by the rotor on the bearing in the direction of the axis of symmetry are lessened.

Abstract: An electrostatically levitated micromotor is described that includes a generally planar rotor that exhibits an axis of symmetry and includes electrically conductive portions. A balanced stator arrangement is positioned adjacent the rotor and is connected to multi-phase circuitry for enabling the rotation of the rotor about its symmetry. A plurality of levitating electrodes are positioned about the rotor and circuitry is connected thereto for forming resonant circuits that include the conductive portion of the rotor and exhibit a natural resonant frequency. A power source energizes the resonant circuits at a frequency greater than the natural frequency and thereby enables stable levitation of the rotor.

Abstract: A radial field electrostatic micromotor produced by photolithographic micromanufacture includes a stator provided with several groups of electrodes angularly offset from one another about an axis of rotation of the micromotor, an electrically conducting rotor at least one arm of which has a counter electrode adapted to cooperate with the stator electrodes to form an air gap therebetween, and a guide ring adapted to drive the rotor in rotation and possibly in translation. The micromotor has a rotor comprising at least one bridging element arranged at least partly above an electrostatic field plane (PCE) of the micromotor. The bridging element constitutes an elevated arm of the rotor having one or more mechanically or electricity functional members adapted to cooperate with one or more complementary members located in or outside the electrostatic field plane and inside or outside the group of stator electrodes.

Abstract: A miniature motor driven by a full-wave or half-wave rectified power source, having a stator of a two-pole field system using a permanent magnet as magnetic poles, a rotor comprising a winding wound on a four-pole core, and noise-suppressing capacitors disposed between adjoining core arms of the four-pole core of the rotor.

Abstract: In a preferred embodiment, an oscillating stepping motor having only one stator phase. What would otherwise be a second stator phase is a magnet fixedly disposed with respect to the rotor to produce a detent position of the rotor. When the stator is energized, the field of the fixed magnet is at least partially overcome and the rotor steps to a first predetermined position. When the stator is de-energized, the rotor returns to the detent position. Alternately energizing and de-energizing the stator causes the rotor to oscillate between the two positions. Alternatively, an angle of oscillation twice that produced above may be provided by reversing the stator field to oscillate the rotor between the first predetermined position and a second predetermined position produced by reversing the stator field.

Abstract: A stepping motor for a timepiece has a coil (12), a single magnetic circuit, two stator pole pieces (10a, 10b), and two rotors in the form of axially magnetized permanent-magnet disks (13, 14). The two rotors are coaxial and disposed one on each side of a plane defined by the stator pole pieces defining gaps of different widths (.delta.1, .delta.2) between adjacent facing surfaces of said respective disks and said stator pole pieces.

Abstract: The invention relates to a rotor (10) for an electric motor, in particular for a multi-phase or single-phase electric motor, comprising a permanent-magnetic ceramic rotor cylinder (1) made of an imperforate solid material and provided with moulded-on plastic elements (5) on at least the cylinder end faces (3), which elements carry axially projecting shaft portions (6) for rotatably journalling the rotor (10), the cylinder end faces (3) being formed with recesses and the moulded-on plastic elements (5) engaging in the recesses (4).

Abstract: The energization coil device provided by the invention comprises a planar support element (30) consisting of a semi-conductive substrate, and at least one planar coil (BI) formed on a first layer (CI) in the vicinity of one surface (F1) of the substrate. The device is characterized in that it further comprises at least one second planar coil (BS) formed in the vicinity of said one surface (F1) of the substrate on a second layer (CS) superposed on the first layer (CI), these coil layers (CI, CS) forming a monolithic and integrated arrangement of several, respectively upper and lower, adjacent layers in one substrate. The device is primarily intended for use in a polyphase electromagnetic micromotor intended to operate as a stepping motor, a continuous rotation motor or a bidirectional motor.

Abstract: A rotor insulating core for miniature motors comprising a stator having a field-forming permanent magnet, a rotor having a rotor winding wound on a rotor core fixedly fitted to a motor shaft; an insulating core being disposed on the surface of the rotor core; and the rotor winding being wound on the rotor core via the insulating core, in which the insulating core consists of an insulating end-face portion covering the end face of the rotor core and an insulating rib covering the side of the rotor core; both being integrally formed; the insulating rib is formed in such a fashion as to have a thickness smaller than the insulating end-face portion and a predetermined length, and disposed in such a manner as to cover the rotor core on which the rotor winding is wound.

Abstract: A housing for electric motors of the type to be used in stirring apparatus and other household appliances has two mirror symmetrical shells with abutting external flanges which are riveted to each other. The median portions of the shells have aligned openings for a portion of a stator which surrounds a rotor on the motor shaft. The shaft further carries a fan wheel and a commutator. The openings are flanked by pairs of bridges which are provided on the respective shells and have integral sockets for spherical enlargements of the shaft. At least one of the shells has a bridge which carries a bearing sleeve for an output element which receives torque from the shaft.

Abstract: A microfabricated, harmonic side-drive "wobble" type micromotor exhibiting increased torque output without the need for air levitation or for insulation on the rotor. Stator pieces are arranged about a circular space. In the center of that space is a bearing. An annular rotor in the space, about the bearing, has an inner surface always in rolling contact with the bearing. The outer surface of the rotor is separated from the stator by an air gap.

Abstract: A miniature motor having a frequency generator comprising a miniature motor consisting of a stator equipped with a permanent magnet for forming a magnetic field, and a rotor having windings wound on a rotor core, constructed so as to feed electric current to the rotor windings through a commutator which makes sliding contact with current-feeding brushes held by a brush holder fixedly fitted to a small motor case. A frequency generator is provided consisting of a rotor for detecting revolution, a stator disposed in such a manner as to face the rotor, a permanent magnet for forming a magnetic field between the rotor and the stator, and a frequency-detecting coil generating an induced voltage proportional to the revolution of the rotor.

Abstract: A small stepping motor has a rotor comprised of a rotatably mounted and radially magnetized permanent magnet having a plurality of magnetic poles, a stator having a plurality of magnetic pole portions positioned to face the rotor, a coil wound around the stator, and a driving circuit for controlling the exciting current supplied to the coil. A leakage flux converging member is positioned in the vicinity of the stator so that leakage magnetic flux from the stator or the coil is converged by the leakage flux converging member so as to pass through the stator.

Abstract: A small-sized electric motor is provided with a hole for inserting a circuit breaker in a holder base lying between a motor case and a gear case, and the circuit breaker is fixed to the holder base by inserting its own body in the hole of the holder base together with terminals at the state in which the terminals are in contact with electrical connective plates of the circuit breaker respectively, it is possible to fix up the circuit braker to the holder base of the motor by merely press-fitting and becomes possible to automate the assembly of the motor housing and the built-in circuit breaker.

Abstract: Briefly stated, the invention comprises an improved stepping motor and method of making it including locating it in the timepiece frame, the stepping motor including a rotor and a stator. A flat magnetizable stator member defines a central opening with diametrically opposed narrow sections on either side of the opening, a non-magnetic bushing disposed in the opening and secured to the surface of the stator member. The bushing has diametrically opposed cut-out portions aligned with the narrow sections. The narrow sections are severed to separate the stator into two pole shoes which are retained in position by the bushing. The severing is preferably by laser, but may includes sawing or other severing methods. The pole shoes of the stator member are then attached to the timepiece frame plate. The stepping motor rotor is journalled in bores formed in the frame and bushing.

Abstract: In a motor, in particular for the electrical driving of a clockwork, a rotor (32) which is mounted rotatably together with a shaft (3) consists of a permanent magnet having diametrically opposite permanent magnet poles. A coil arrangement in the motor comprises two coils (10 and 11) arranged at angular distances of, in particular, 90.degree. apart from each other.

Abstract: A mass to be levitated is provided with an electrically conductive surface that is acted upon by an oscillating electrical force field generated by a plurality of charged conductive plates. The levitated mass is kept in static equilibrium in the electric field by driving the resonant circuit with an applied time varying voltage that has a frequency greater than the natural frequency of the resonant circuit. Motion of the mass is accomplished by providing actuator elements that are selectively charged to attract the mass in a given direction. Alternatively, the mass may be moved by employing a plurality of levitation control circuits that are sequentially energized.

Abstract: An electrostatic micro-motor apparatus capable of transmitting a driving force of an electrostatic micro-motor comprises a rotor which has the shape of a gear substantially. A plurality of electrodes are disposed at a predetermined circumferential region around the rotor so as to confront the teeth of the rotor, and such that a circumferential gap is defined at the remaining circumferential region around the rotor. A transmission gear is provided in the circumferential gap so as to be brought into engagement with the rotor.

Abstract: A miniature motor with a frequency generator comprising a motor portion having a stator with a permanent magnet for forming a magnetic field and a rotor with rotor windings wound on a rotor core; electric current being fed to the rotor windings via a commutator making sliding contact with brushes, and a frequency generator for detecting the revolution of the motor, in which the frequency generator comprises a frequency generator rotor, mounted on the motor rotor, having a disc-like rotor portion made of a soft magnetic material and equipped with a plurality of magnetic-pole teeth on the outer periphery thereof, an internal-gear core of an annular disc shape, made of a soft magnetic material, disposed in such a manner as to come in contact with the inside of a motor housing and face the outer circumferential surface of the rotor portion and equipped with a plurality of magnetic-pole teeth on the inner periphery thereof, a permanent magnet forming a magnetic field between the magnetic-pole teeth of the rotor po

Abstract: In a direct-current machine comprising a permanent-magnetic stator, the detent torque or resting moment of the rotor is to be reduced by simple and low-cost technical means. This is achieved by disposing the permanent-magnet shells of the stator asymmetrically with respect to each other.

Abstract: Electrical component equipped with contacts for its electrical connection with its electrical environment. It is provided with two sets of contacts interconnected electrically by groups of two contacts belonging respectively to these two sets. One of these sets of contacts is constituted by contacts adapted to ensure electrical connections by simple pressure contact on respectively oppositely situated conducting spots, mechanical fastening means being also provided to fix the electrical component mechanically to a support associated with said conducting spots. The other of these sets of contacts is constituted by contacts adapted to be connected mechanically, particularly by welding, to respective conducting members or conducting spots.

Abstract: Method for manufacturing a timepiece stepping motor comprising the steps of: providing a flat one-piece stator member defining an opening for the rotor and having a pair of diametrically opposed narrow sections on either side of the opening; providing a movement frame having stator locating projections and defining a pair of holes larger than the narrow sections and extending through the movement frame; locating and attaching the stator to the frame with the narrow sections spanning the holes in the frame; cutting through the narrow sections with a laser to sever the stator into two members, utilizing the holes in the frame to dispose of vaporized metal from the stator; encapsulating and re-joining the severed sections with a plastic fixation; and attaching a coil core assembly to the stator members and in magnetic circuit therewith.

Abstract: Electro-mechanical timepiece, comprising a circuit for generating electric pulses that appear at suitable points of time, a stepper motor controlled by said pulses and comprising a rotor (2) with permanently magnetic poles (8,9), a stator (3,4,5) and a coil (6), as well as a gear driven by the action of the step motor for driving the clock hands, the stator being constructed from two stator parts (3,4) situated on either side of the rotor and a yoke (5), connecting these two parts and extending through said coil. The poles (8,9) are situated in a same cross section plane, perpendicular to the rotation axis of the rotor, and form a ring-shaped layer (14) which is thin in radial direction. According to a preferred embodiment the rotor is at the radial inner side of the poles provided with an uninterrupted round-going ring-shaped portion (7) of soft-magnetic material.

Abstract: A miniature motor comprising a motor case having a bearing on the closed end face thereof, a stator consisting of a permanent magnet, brushes and terminals; and a rotor fixedly fitted to a motor shaft in the motor case and having core windings and a commutator; the rotor being rotatably supported by the bearing; in which the rotor and the stator are adapted so that the balance of magnetic field intensity between the stator and the rotor becomes unbalanced structurally or magnetically, thereby causing the rotor to be biased within the bearing in a predetermined positional direction with respect to the stator.

Abstract: An improved stepping motor rotor assembly comprises a rotor having a shaft and a driving member such as a gear pinion, a centering washer disposed on the shaft and a recess with a short finished cylindrical wall coaxial with the shaft and annular abutment surface at the bottom of the recess, a rare earth permanent magnet having a rough center hole preferably drilled by laser beam defining an annular clearance with the shaft and having a finished outer cylindrical wall extending into the recess with a loose fit to center the magnet with respect to the rotor axis, and a holding washer forming an interference fit with the shaft and pressing the magnet axially against the abutment surface on the centering washer. The centering washer may be restrained in axial position by a light interference fit with the shaft or it may be held by contacting the driving member.

Abstract: A miniature motor comprising a stator having permanent magnets constituting a two-pole field, and a rotor having rotor windings wound on a rotor core of a three-pole construction, in which the rotor core is formed in such a manner that the cross-sectional shape of the rotor core normal to the motor shaft is made symmetrical with respect to the radial center line of each pole thereof and that the gap between the permanent magnets and a predetermined range from the center line of the arc-shaped outer periphery of the rotor core facing the permanent magnet is made larger than the gap between the permanent magnet and at least part of the other range of the outer periphery of the rotor core.

Abstract: A small sized electric motor of a sectionally non-circular housing has a pair of magnets oppositely positioned therein in the lengthwise direction thereof and a rotor positioned between the magnets. A pair of fulcrums oppositely located on the housing in the length-wise direction thereof diametrically across the rotor, and a pair of elongated brushes, each has one end part secured to each of the fulcrums and the other end part elastically pressed against the commutator of the rotor at a point thereof to determine the electric displacement point with the angle 120.degree. displaced with respect to the magnetic line of force caused by the magnets. A winding is wound around the core structure of the rotor and has the initial ends and the wound ends each connected to a predetermined number of connector terminals of the commutator with the angle 120.degree. displaced with respect to the commutator.

Abstract: A small electric motor has a housing which is secured to a cover. The cover has a longitudinally-extending guide member formed on one side thereof which partially surrounds the stator. A longitudinal groove which is formed in the guide member engages with a projection formed on the outside of the stator. An external connection terminal is secured to the cover and is electrically connected to the stator coil by a stator coil terminal which passes through an access hole formed in the guide member.

Abstract: A miniature motor having a metallic case with a printed circuit board installed therein. The printed circuit board has an electronic circuit, mounted thereon, for controlling the miniature motor. A lug portion is provided protruding from the edge of an open end of the metallic case. An engaging portion is provided for engaging the lug portion with an earth terminal of the printed circuit board. The earth terminal and the lug portion are electrically joined by means of soldering in a state the printed circuit board is fitted to the metallic case in such a manner as to engage the lug portion with the engaging portion.

Abstract: A brushless generator having a rotor for generating a magnetic field, a stator having magnetic poles facing the rotor a main generating winding; and a voltage is induced as the magnetic field generated in the rotor intersects the main generating winding, in which slots are provided at the locations of the stator magnetic poles facing the rotor, exciting windings are wound on the slots to generate in the exciting windings voltages having different phases with respect to that of the voltage generated in the main generating winding, and brushes are eliminated by using the voltages generated in the exciting windings.

Abstract: A permanent magnet type electric motor has stoppers for restricting axial movement of field magnetic poles each composed of a permanent magnet and an auxiliary pole 13 in a cylindrical yoke thereof. The stoppers may be protrusions 17 arranged in the yoke or may be a ring member 21 resiliently fitted in the yoke. The auxiliary poles 15 are welded to an inner wall of the yoke 11 and the magnets 14 may be bonded thereto by a suitable adhesive so that enough space to receive a through-bolt is provided between adjacent ones of the field magnetic poles.

Abstract: A rotor for miniature motors having an annular spark-quenching element for suppressing electrical sparks generated between commutator segments and brushes, in which the commutator segment is composed of a commutating portion coming into sliding contact with the brushes, and a terminal portion connected to a lead wire of a rotor winding; the terminal portion having an element-retaining portion on which the annular spark-quenching element is mounted; and the annular spark-quenching element being electrically connected to the element-retaining portion, as mounted thereon.

Abstract: A miniature motor having installed motor components in a housing made of a metallic material and formed into a bottomed, hollow cylindrical shape with an opening at one end thereof; a cover made of a metallic material and formed into a plate shape being fixedly fitted to the opening, in which a plurality of minute ridges are provided on the outside circumferential surface of the cover, and the outside dimensions of the cover are made equal to, or slightly larger than, the inside dimensions of the housing opening so as to ensure a firm press-fit between the cover and the housing opening, thereby maintaining electrical contact between both.

Abstract: A miniature motor using a rubber magnet for the permanent magnet for creating a field, in which a coating film is formed on the rubber magnet.The coating film is gas-impermeable, possibly of suitable synthetic resin, to prevent any harmful gas generated in the rubber magnet from escaping therefrom and damaging the contact surfaces of the motor.

Abstract: A shallow cup-shaped miniature motor having a motor case of a substantially shallow cup shape, fitted with a permanent magnet field; a motor case cover engaged with the open end face of the motor case; a rotor having a motor rotating shaft rotatably supported by a first bearing provided on the closed end face of the motor case and a second bearing provided on the motor case cover; brushes supported by the motor case cover for making sliding contact with commutator segments provided on the motor rotating shaft, in which an insulating core having wing portions substantially covering a laminated core comprising the rotor is provided on the outermost end face of the laminated core; the insulating core having at the center thereof a through hole through which the motor rotating shaft is passed, and a hollow cylindrical portion, provided around the through hole, having a plurality of notches for engaging with a plurality of the rising portions of the commutator segments; a commutator surface comprising the commutat

Abstract: Designed especially for hand-held dictation devices the motor has a three-phase external stator and two-pole permanent-magnet internal rotor, the two enclosed by an external housing from one axial end of which the rotor shaft projects out, its other axial end provided with a thrust bearing for the rotor shaft's other end. At least one Hall element, although more typically three, is provided, located at the peripheral edge of one of the axial ends of the rotor to sense axially emanating stray rotor flux. The rotor is directly secured to the rotor shaft, the shaft being ferromagnetic and near its outwardly projecting end provided with a ferromagnetic bearing mounted in a ferromagnetic end plate, so that stray flux sensed by the Hall element can travel from the rotor to the Hall element along a magnetic circuit for such sensed stray flux, but with the magnetic circuit being made up of motor components and structural parts that are required anyway.

Abstract: Miniature rotary machinery with brushgear comprising two arm guides, to which power supply voltage is fed, provided on the inside of a motor case cover; and brush arms having brushes at the tip thereof and brush arm eyes, for rotatably engaging with the arm guides, at the other end thereof, and spring receptacles, made of an insulating material, at the center thereof; both ends of an arc-shaped leaf spring being engaged with the spring receptacles to impart pushing force to the brushes by the resiliency thereof; the brush arm eyes being disposed so as to make contact with the arm guides at a predetermined angle; each of the brush arm eyes having a formed portion whose crosssection includes two mutually intersecting tangent lines making contact with the circular crosssection of the arm guide so that two-point contact is established between the formed portion and the arm guide, when viewed in the crosssectional direction; and if necessary projections or ridges provided on the outer circumferential surface of th

Abstract: A molded plastic housing for a small electric motor having a radial end wall and an axially projecting portion for mounting the stator and journalling the motor shaft. An annular stator is mounted on and about the projecting portion and shaft bearings are mounted in axially spaced relationship in interference fit respectively at end sections of the housing portion and in direct engagement with the molded plastic. Reduced diameter and reduced thickness zones at the end sections provide for resilient and firm bearing retention and alignment. Four (4) circumaxially spaced slots at each end section with flats radially inwardly thereof provide for the reduced thickness and reduced diameter. The bearings engage the flats in an interference fit.

Abstract: A stepping motor for use in a clock includes a rod core having an effective length L, and a coil wound around the rod core along the effective length L and having a thickness R defined between the center of the rod core and the outermost periphery of the coil. The effective length L and the thickness R satisfy the relation 10.ltoreq.L/R.ltoreq.40. A stator is magnetically connected between the ends of the rod core. A rotor is rotatably disposed between opposed magnetic poles of the stator, and the rotor has a circular shape of a radius r.sub.0 in the range of 1 to 2 mm. Electric pulses having a pulse width t in the range of 9 to 17mS are applied to the coil so that the stepping motor converts more than 20% of the electric energy of the pulses into rotational torque of the rotor.