Abstract: A nut driven by a lead screw and stepper motor has an internal concave recess for holding high viscosity grease that is semi-solid at ambient temperature and spaced from the lead screw. Grease flow ensues with lead screw motion causing a slow flow of grease coating the lead screw with a thin coating of grease as the nut travels back and forth over the lead screw. The nut may be an anti-backlash nut or a single member nut with both having a concave recess about the lead screw for the grease.

Abstract: A step motor integrates its mounting face and heat sink into the stator design. In particular, mounting holes (typically, four in number) are provided through the stator stack in outer perimeter areas. The stator stack itself becomes the mounting surface, allowing the heat generated from the stator to conduct directly to the mounting plate. The front end cap for holding the rotor in alignment is situated inside of the stator's mounting surface and takes no part in mounting the motor to the mounting surface. The end caps only hold the rotor in proper relation within the stator and contain the bearing assembly for the rotor's axial drive shaft. The perimeter of the stator assembly between the mounting screw holes may have saw-tooth cutouts that define heat-dissipation fins.

Abstract: A stepper motor is provided in which a permanent ring magnet is sandwiched in an outer part of the stator winding assembly located far from the gap between rotor and stator teeth, so that magnetic flux in the gap is dominated by the Ampere-turns of energized stator coils and therefore more easily controlled for reduced vibration at low stepping speeds. The rotor need not contain any permanent disk magnet. If one is provided, it can be completely embedded within the rotor and merely supplement the primary flux from the stator to enhance torque. In most cases, where the rotor lacks any permanent magnet, the motor's axial shaft can have a larger diameter and may, together with the rotor, form a linear actuator.

Abstract: A stepper motor is provided in which a permanent ring magnet is sandwiched in an outer part of the stator winding assembly located far from the gap between rotor and stator teeth, so that magnetic flux in the gap is dominated by the Ampere-turns of energized stator coils and therefore more easily controlled for reduced vibration at low stepping speeds. The rotor need not contain any permanent disk magnet. If one is provided, it can be completely embedded within the rotor and merely supplement the primary flux from the stator to enhance torque. In most cases, where the rotor lacks any permanent magnet, the motor's axial shaft can have a larger diameter and may, together with the rotor, form a linear actuator.

Abstract: A stepper motor has electromagnetically driven stator segments facing corresponding rotor segments. In order to reduce vibration of the stator segments, motor body end caps are provided with a stepped annular rim along an inside diameter of a centering sleeve. The stepped rim bears against each axial end of the stator segments, with a radial dimension and an axial dimension bracketing a stator segment end in place.

Abstract: A step motor having a stator constructed with six teeth per pole is achieved for a stator inner diameter (ID) less than one inch (25.4 mm) by a either (1) reducing the pitch angle of the outer teeth of each pole (e.g., to at most 6.8 degrees for a 19 mm stator ID), or (2) narrowing the tooth width of those outer teeth (e.g., to at most 0.0175 inch or 0.444 mm for a 19 mm stator ID), or (3) combination of both. These changes allow sufficient space (i.e., wider than 0.052 inch or 1.321 mm) between poles for passage of a winding needle, even with the extra stator teeth. Although narrowing the pitch angle and reducing the tooth width do sacrifice some torque contribution from each tooth, there still results a net overall gain in torque.

Abstract: A rotary machine (e.g., motor or generator) has end caps with plastic piloting rings that engage a stator's plastic winding frame in an interference fit, so that a rotor seated by bearings in the end caps is properly aligned with the stator. The flexibility of the plastic-to-plastic fit allows looser tolerances in comparison to machining of all-metal end caps, while the average circle of the piloting ring's outer diameter still assures proper concentricity of rotor shaft, bearings, piloting rings and stator.

Abstract: A motor is provided with a set of end cap guides on the ends of a stator winding assembly to pilot the placement of end caps into the correct placement relative to the stator winding assembly so that the rotor assembly is maintained concentric with the stator. The end cap guides may be rings fitting within the winding insulators on the ends of the stator stack or may be integrated as guide segments with the winding insulators to outline an interrupted cylindrical inner surface coinciding with the inner diameter of the stator winding assembly. The guides allow proper positioning of the rotor assembly without increasing the stator stack length.

Abstract: A two-phase permanent magnet step motor comprises a permanent magnet rotor having an equal number Nr of magnetic north and south poles defining a fundamental step angle ?=90°/Nr, such that a number of steps per revolution of the rotor is 360°/?, and a toothless hybrid stator with windings defining a number Ns of stator poles, with Ns being divisible by four and a ratio Nr/Ns=n/4, n being an odd integer. The permanent magnet rotor may comprise a set of rare-earth magnets. Preferably, Nr is at most 10 (i.e., not more than 20 rotor poles). A method of driving the step motor continuously applies successive current phases to the windings with the motor speed being controllable simply by the step pulse rate. The motor can be micro-stepped at low speeds for smooth operation.

Abstract: A rotary machine (e.g., motor or generator) has end caps with plastic piloting rings that engage a stator's plastic winding frame in an interference fit, so that a rotor seated by bearings in the end caps is properly aligned with the stator. The flexibility of the plastic-to-plastic fit allows looser tolerances in comparison to machining of all-metal end caps, while the average circle of the piloting ring's outer diameter still assures proper concentricity of rotor shaft, bearings, piloting rings and stator.

Abstract: A motor is provided with a set of end cap guides on the ends of a stator winding assembly to plot the placement of end caps into the correct placement relative to the stator winding assembly so that the rotor assembly is maintained concentric with the stator. The end cap guides may be rings fitting within the winding insulators on the ends of the stator stack or may be integrated as guide segments with the winding insulators to outline an interrupted cylindrical inner surface coinciding with the inner diameter of the stator winding assembly. The guides allow proper positioning of the rotor assembly without increasing the stator stack length.

Abstract: A belt and roller system comprising a roller having a permanent magnet sandwiched in between a pair of temporarily magnetic disks with the magnetism of the disks induced by the permanent magnet. Each temporarily magnetic disk may be steel. Each pole of the permanent magnet is disposed adjacent to a pole of one of the temporarily magnetic disks resulting in a magnetic attraction to a disk at each pole of the permanent magnet. The opposing magnetic poles of the disks form a magnetic flux circuit by which a temporarily magnetic belt, such as a steel belt is guidable to prevent or reduce deviation which it may have from its roller path. Additional permanent magnetic rollers or other rollers known in the art may be combined with the magnetic roller of the present invention to form a gear train about which the belt rotates.

Abstract: A hybrid step motor has axially spaced first and second sets of rotor sections (or alternatively different sets of stator sections) characterized by different tooth widths. The rotor/stator tooth width ratio in one set is optimized for one-phase ON operation while the rotor/stator tooth width ratio for the other set is optimized for two-phase ON operation. More generally, the two sets are optimized together for near sinusoidal, torque profile and substantially equal microsteps.

Abstract: A stepper motor includes a rotor having equally spaced rotor teeth defining a full step angle, and a stator with stator poles wound with coils that can be driven in a series of phases so as to magnetically interact with the rotor to produce stepping motion. The stator poles have teeth organized into two groups when there is an even number of stator teeth per pole, or into three groups for an odd number of stator teeth per pole. The stator teeth have an average pitch different from the rotor's tooth pitch, but the groups of stator teeth are also displaced relative to other groups by a specified offset angle of one-half or one-quarter step to double the number of detent positions, and to displace such detent positions from full one-phase ON or two-phase ON positions.

Abstract: A belt and roller system comprising a roller having a permanent magnet sandwiched in between a pair of temporarily magnetic disks with the magnetism of the disks induced by the permanent magnet. For example, each temporarily magnetic disk may be steel. Each pole of the permanent magnet is disposed adjacent to a pole of one of the temporarily magnetic disks resulting in a magnetic attraction to a disk at each pole of the permanent magnet. The opposing magnetic poles of the disks form a magnetic flux circuit by which a temporarily magnetic belt, such as a steel belt is guidable to prevent or reduce deviation which it may have from its roller path. Additional permanent magnetic rollers, as described above, or other rollers known in the art may be combined with the magnetic roller of the present invention to form a gear train about which the belt rotates.

Abstract: A belt and roller system comprising a roller having a permanent magnet sandwiched in between a pair of temporarily magnetic disks with the magnetism of the disks induced by the permanent magnet. For example, each temporarily magnetic disk may be steel. Each pole of the permanent magnet is disposed adjacent to a pole of one of the temporarily magnetic disks resulting in a magnetic attraction to a disk at each pole of the permanent magnet. The opposing magnetic poles of the disks form a magnetic flux circuit by which a temporarily magnetic belt, such as a steel belt is guidable to prevent or reduce deviation which it may have from its roller path. Additional permanent magnetic rollers, as described above, or other rollers known in the art may be combined with the magnetic roller of the present invention to form a gear train about which the belt rotates.

Abstract: A hybrid step motor creates additional detent positions between successive drive phases of the motor for smooth motion and micro-step accuracy. A multi-section rotor has two sets of rotor sections that are displaced by the standard one-half rotor tooth pitch plus-or-minus an additional displacement angle equal to one-quarter of the fundamental step angle. The motor can also employ a stator in which two groups of teeth on the stator poles are displaced from the standard stator tooth pitch by an amount selected to create even more detent positions.

Abstract: A hybrid step motor has axially spaced first and second sets of rotor sections (or alternatively different sets of stator sections) characterized by different tooth widths. The rotor/stator tooth width ratio in one set is optimized for one-phase ON operation while the rotor/stator tooth width ratio for the other set is optimized for two-phase ON operation. More generally, the two sets are optimized together for near sinusoidal, torque profile and substantially equal microsteps.

Abstract: A roller system comprising a pulley having a permanent magnet sandwiched in between a pair of temporarily magnetic disks with the magnetism of the disks induced by the permanent magnet. For example, each temporarily magnetic disk comprises steel. Each pole of the permanent magnet is disposed adjacent to a pole of one of the temporarily magnetic disks that is of an opposing polarity resulting in a magnetic attraction to a disk at each pole of the permanent magnet. The opposing magnetic poles form a magnetic flux circuit by which a temporarily magnetic belt, such as a steel belt is guidable to prevent or reduce deviation which it may have from its roller path. Additional permanent magnetic rollers, as described above, or other rollers known in the art may be combined with the magnetic roller of the present invention to form a gear train about which the belt rotates.

Abstract: A half-stepping motor with bifilar coil windings about its stator poles has two layers of stator coils with different numbers of turns per pole for each layer. The ratio between the number turns is selected to provide a desired angular phase shift in the torque profile. A first layer wound about a first group of poles is connected in series in a forward sense with a second layer wound about a second distinct group of poles and driven by a first phase, while a second layer wound about the first group of poles is connected in series in a reverse sense with a first layer wound about the second group of poles and driven by a second phase in quadrature relation to the first phase. For a motor with 8 stator poles, the desired phase shift is 22.5 degrees, resulting from a turn ratio between the layers of about 0.4142.