Abstract: Since the true power density of gearing is a function of the dynamic load, maximization of this critical performance property can be achieved only if both the static component and the dynamic increment of load are minimized. The invention discloses how these two objectives may be achieved in the same gear set. Both static and dynamic tooth stresses are minimized by forming the gears to have an optimum load distribution, a feature realized by using a new type of modification that minimizes the tooth surface relief area. The second requirement, of minimizing the dynamic increment, is accomplished in helical and spiral bevel gearing by proportioning the teeth to have a fully elastic "self-complementary" tooth pair stiffness curve, which gives a mesh stiffness characteristic that remains substantially constant throughout the entire tooth pair engagement angle at all loads and all speeds.

Abstract: A new system of modifications for power train gearing, called "differential crowning," has both advantages and disadvantages over the previous system of modifications based on tip and/or root relief. The advantages of differential crowning are three-fold: (1) it affords substantially constant stiffness, so that it is equally effective at all loads; (2) it is adapted to minimize both first and second harmonic excitations, whereas conventional modifications can mitigate only the first harmonic excitation, and that only at one "design load;" and (3), it is as insensitive to manufacturing inaccuracies as conventional gearing is sensitive to them. Differential crowning, however, has two disadvantages in its previously disclosed forms: (1) it is difficult to optimize; and (2), it is more expensive than conventional modifications unless the production runs are very large.

Abstract: Spectrum analyses of gear noise show that the predominant frequencies are the tooth contact frequency (1.times.TCF) and twice the tooth contact frequency (2.times.TCF). The reason for this is that at two positions in the tooth engagement cycle, the effective mesh stiffness of conventional gearing differs substantially from the ideal mesh stiffness that eliminates the dynamic increment of load. One of these two positions occurs once per tooth engagement cycle and the other one twice, giving rise to the 1.times.TCF and 2.times.TCF excitations respectively. These periodic fluctuations in the effective mesh stiffness, which are in proportion to what is called "static transmission error," produce inertia forces between engaged teeth that increase with both speed and proximity to the critical (resonance) speed of the gear pair. In conventional gearing the dynamic increment of load generated by these inertia forces can be as large as or even larger than the useful transmitted load.

Abstract: The usual expedient employed by gear designers seeking to reduce gear noise at all loads has been to specify finer teeth, which in effect trades away torgue capacity for quietness. The present disclosure describes a tooth form that substantially eliminates gear noise while at the same time significantly increasing torque capacity. This tooth form involves (a) the synchronization of the loading and unloading phases of tooth engagement with the inverse phases (i.e., unloading and loading phases, respectively) of another tooth pair, combined with (b) the introduction of particular patterns of topographic tooth surface crowning that transform the elastic tooth pair stiffness curve into a curve that not only maintains this synchronization at loads greater or smaller than the design load but also eliminates transmission error to any extent desired.

Abstract: The invention discloses means to reduce the noise and vibration of gear sets by (a) minimizing the transmission error resulting from variations in the mesh stiffness at different phases of tooth engagement and (b) reducing the maximum rate at which load is transferred to the driven gear. A substantially constant mesh stiffness is achieved by shaping the teeth and the field of contact so the product of incremental tooth contact line length and tooth pair stiffness per unit length of tooth contact line integrated over the field of contact does not vary significantly as the tooth contact lines move across the field of contact. In addition, the maximum rate at which load is transferred to the driven gear is substantially reduced by shaping the teeth so the tooth contact lines intersect the entry and exit boundaries of the field of contact at an angle.

Abstract: A system of gearing that allows gears to be designed that are smaller than standard involute gears of corresponding torque capacity. This reduction in size is made possible by increasing the angle through which the teeth are engaged. The wider angle of engagement is achieved by adding to the path of contact two segments: (1) the path portion closest to the pinion is extended by adding on a slightly curved segment lying outside the circle that is the locus of interference points for involute gearing; and (2), the path portion closest to the gear is extended by adding a segment that is produced by the use of an exceptionally long pinion addendum. The reduced size of the gears made possible by the wider engagement angle obtained from addition of these two path segments not only reduces mass and pitch line velocity, but the wider engagement angle itself also affords an increased profile contact ratio that reduces transmission error. The wider angle of engagement thus reduces noise excitation in two ways.

Abstract: The invention discloses means to reduce the noise and vibration that result from gear transmission error produced by variations in the mesh stiffness at different phases of tooth engagement. A substantially constant mesh stiffness is achieved by proportioning the teeth and the field of contact so that the product of incremental tooth length and tooth load per unit length at a given torque load integrated over the field of contact does not vary significantly as the tooth contact lines move across the field. To minimize deviations from the mean mesh stiffness, the teeth are made as flexible as possible and the total contact ratio as large as possible.

Abstract: The invention discloses a means of increasing the maximum allowable load on mechanical elements that roll on each other, such as the members of constant or variable speed friction drives, ball or roller bearings, rollers, etc. The increased allowable load is achieved by constructing at least one of the elements that roll on each other in two parts, including a rolling-surface part that is heavily preloaded by one or more additional parts that induce large compressive stresses on the principal planes normal to the rolling-surface. Optimum materials for the rolling-surface part are those that have a large modulus of resilience, since these materials afford the maximum allowable load capacity. In addition to hardened steels, such materials include shape-memory materials, reinforced plastics, bronze and aluminum alloys, and chilled cast iron. Shape-memory materials in particular have the advantage of simplifying the supporting structure, especially when the rolling surface is convex.

Abstract: A gear tooth form is disclosed that maximizes the profile (transverse) contact ratio for coplanar axis gearing. As the tooth form allows teeth two or three times as fine as those of conventional involute gearing to be used without loss of torque capacity, the face (axial) contact ratio for helical or spiral bevel gearing is also maximized. The total contact ratio (profile plus face contact ratios) is therefore maximized, and the torque load is divided over the maximum number of teeth. This minimizes the transmission error, which in turn minimizes operating noise and vibration. The gearing employs a minimum pressure angle and a path of contact that includes a curved portion.

Abstract: Gear tooth profiles are disclosed that afford a higher torque capacity than that of previously disclosed fine-pitch gearing. To offset the weakness in bending of fine teeth, the transmitted force is divided among two to five times as many teeth as in conventional gearing, by using very low pressure angles, and the tooth interference that would occur between meshed involute teeth of equally small pressure angle is avoided by using profiles of shorter relative radius of curvature. The tooth flexibility needed to offset tooth separation at the ends of the line of action and to insure an equitable division of the load among the maximum number of teeth is obtained by deepening the dedenda. The resulting tooth form increases torque capacity by maximizing the transverse contact ratio and minimizes operating noise by increasing the axial contact ratio.

Abstract: The invention discloses a form of gearing that is radially preloaded and utilizes closely conforming teeth. The preloading ensures that the higher torque capacity of conformal teeth can be realized more fully than in fixed center gearing, and the conformal tooth profiles, if concave-convex, ensure that the amount of preload needed is minimized, since the effective pressure angle for such teeth diminishes as the transmitted torque increases.

Abstract: The principal disadvantage of conformal gearing is its acute sensitivity to center-distance error. An improved type of all-addendum conformal gearing is disclosed in which the concave tooth is much more flexible than the convex tooth, so that if the gears are mounted at too great a center-distance, the tendency of the tooth load to be exerted on the tip of the concave tooth is offset by tooth flexure which shifts the arc center of the concave profile a considerable distance toward the axis of the gear with convex teeth. This increases the pressure angle sufficiently to prevent overloading of the tip of the concave tooth.

Abstract: Gear silhouettes in the axial plane are tailored to give substantially constant tooth load per unit length of contact are as well as constant position of the resultant tooth load, even though the number of teeth in contact fluctuates. These tailored silhouettes help to minimize noise, bearing vibration and dynamic-load tooth-stresses.

Abstract: Novikov gearing obtains its exceptional tooth surface load capacity by using concave-convex circular arc profiles of nearly the same radii, so that the contact area between mating teeth is very large and the Hertzian stress low. Because the centers of these arcs are very close together, a small error in center-distance produces excessive changes in pressure angle and overloads the tips of the concave teeth. The subject invention eliminates this problem by using profile curves having a radius of curvature that increases with distance from the pitch circle. The discrete arc centers of Novikov gearing are replaced by continuous evolute curves which are positioned to be tangent to the pressure line near the point where it passes through the pitch point. This allows much closer profile conformity for a given center-distance error, reducing surface stresses and increasing torque capacity.

Abstract: A type of internal cycloidal gearing based on the principal that different size generating circles rolling inside a directing circle which has a diameter equal to the sum of the diameters of the generating circles generate identical hypocycloids, and, similarly, a generating circle that surrounds a directing circle and gyrates around it like a "hula-hoop" generates the same epicycloid as a small circle having a diameter equal to the difference in the diameters of the surrounding "hula-hoop" circle and the directing circle.

Abstract: A roller bearing construction that eliminates the need for a cage or separator to align and position the rollers. Gear teeth formed on the rollers and races function as spaced apart planetary gear sets to insure correct roller alignment and spacing, reducing friction and wear and increasing load capacity.

Abstract: Gear tooth profiles that afford greater torque capacity than is obtainable from involute gears of corresponding size and materials. Maximum contact stress is reduced by using profile curves that give exceptionally long radii of relative curvature at the pitch point, and interference problems with such profiles are avoided by utilizing a two-segment line of action. When the gears are not carrying a torque load each tooth profile in the transverse plane passes successively through two points of contact but are out of contact at points in between. As the torque load increases, the two contact zones widen until they coalesce.

Abstract: A system of helical or spiral bevel gearing that by violating the "law of gearing" restricts the tooth action entirely to the pitch point. The greatly reduced sliding velocity between the teeth of mating gears permits them to be made of "dry bearing" or other moldable materials without exceeding rated PV values, and a multiplicity of contact points moving transversely along the pitch line insures continuity of action.

Abstract: A form of gearing with teeth having circular arc profiles and a particular pressure angle which together produce engagement and disengagement in pure rolling. The shearing action tangential to the tooth profiles associated with compressive deformation of the tooth faces is made to exactly offset the shearing action in the opposite direction imposed by the meshing of the teeth.