749 results about "Helix angle" patented technology

An expandable stent comprised of a plurality of helical segments is disclosed. In one embodiment, the stent is generally cylindrical in shape having a cylindrical axis, and comprises a first and second set of helical segments. The helical segments in the first set are substantially parallel and have a first pitch forming a first helical angle with respect to the cylindrical axis. The helical segments in the second set are also generally parallel to each other and form a second pitch that differs from the first pitch, thereby forming a second helical angle with respect to the cylindrical axis. In an alternative embodiment, the stent comprises one set of helical segments and a plurality of circumferential elements that are joined together by the helical segments to form a plurality of cylindrical elements which are joined together to form a stent body. The stent may also have endzones.

A rotary drill bit for drilling subterranean formations configured with at least one protective structure proximate to the rotationally leading and trailing edges of a gage trimmer, wherein the at least one protective structure is positioned at substantially the same exposure as its associated gage trimmer. Particularly, the apparatus of the present invention may provide protection for gage trimmers during drilling, tripping, and/or rotation within a casing; i.e., when changing a drilling fluid. Protective structures may be configured and located according to anticipated drilling conditions including helix angles. In addition, a protective structure may be proximate to more than one gage trimmer while having a substantially equal exposure to each associated gage trimmer. Methods of use and a method of rotary bit design are also disclosed.

The present invention relates to a stent providing a high percentage of vessel coverage, preferably at least about 50% of the portion of the vessel covered by the helical elements of the stent. The stent comprises helical elements interposed between strut members in which the helical elements are connected to the strut members by linking elements. The portion of the stent having helical elements provides a high percentage of covered area for example, in an aneurysm area. The linking elements provide part of a mechanism that allows vessel coverage to be maintained as the stent is deployed from a crimped state to an expanded state allowing the helical elements to change its helix angle (the angle at which the helical elements progresses around the circumference and along the length of the stent) and thereby the pitch of the helical elements as the stent is expanded.

A planetary gear set includes a sun gear including a first set of gear teeth having a helix angle and second set of gear teeth formed as a single unit with the first set of gear teeth and having a second helix angle of opposite hand relative to the first helix angle. A ring gear includes a third set of gear teeth having a third helix angle, and fourth set of gear teeth and having a fourth helix angle of opposite hand relative to the third helix angle. Planet pinions, each include a fifth set of gear teeth having a fifth helix angle, and sixth set of gear teeth formed as a single unit with the fifth set of gear teeth and having a sixth helix angle of opposite hand relative to the fifth helix angle.

A split planetary gear assembly having a pair of helical gearsets. The first helical gearset includes a first sun gear, a first ring gear, and a set of first planet gears meshed with the first sun gear and the first ring gear. The second helical gearset includes a second sun gear, a second ring gear, and a set of second planet gears meshed with the second sun gear and the second ring gear. The components of the second helical gearset have the same number of teeth, helix angle, and tooth pitch as the components of the first helical gearset with the exceptions that their angular helix orientation (i.e., left-hand/right-hand) is reversed and they are circumferentially indexed by one-half tooth pitch. In addition, the first and second planet gears are arranged in paired sets and supported on a common pinion shaft which, in turn, is fixed to a planet carrier. The second sun gear is splined for rotation with and limited axial movement relative to the first sun gear.

This invention relates to a screw slot end sealing device used in fluid mechanical rotating shaft characterizing in designing a set of double screw angles, three-dimensional screw slot on a sealed end face of a static ring or a rotating ring in which a screw slot made up of spiral lines at both sides with different angles has a convergent outlook with even wider upstream, high-tension side and even narroder downstream, step-down side and a steadily shalldower depth from high-tension side to step-down side so as to form a three-dimensional convergent screw slot.

A diamond coated drill capable of drilling holes in fiber reinforced composite materials. The drill is made from a tungsten carbide (WC) substrate with cemented cobalt (Co) in a range between about 3 to 10 wt. % and a diamond coating having a thickness in a range between 3 to 20 microns. The drill includes a shank, a longitudinal axis and includes two flutes at a helix angle that is in a range between 25 and 35 degrees with respect to the axis. A margin width is maintained between about 5 to 10 percent of the drill diameter. A body clearance diameter is maintained at between about 92 to 96 percent of the drill diameter. A web thickness before splitting is about 20 to 30 percent of the drill diameter. A clearance angle or lip relief angle is between about 10 and 20 degrees. A chisel edge angle is between about 105 and 120 degrees. A chisel edge length is up to about 0.035 mm. A splitting angle is between about 130 and 150 degrees. A notch angle is between about 30 and 40 degrees with respect to the drill axis. A notch rake angle lies between about −5 and 10 degrees. A split point angle is between about 70 and 100 degrees, and preferably about 90 degrees.

A drill bit for producing holes in composite materials is disclosed. The drill bit includes an elongate drill bit body having a drill bit diameter. The drill bit also includes at least two helical flutes. The helical flutes have a reverse helix angle and a primary cutting edge. The primary cutting edge may have a positive rake angle. The drill bit further includes a point having a point length. The drill bit may also include a cutting tip with a tip angle and a tip length. The tip length is at least twice the drill bit diameter.

A screw with a drilling tail comprises: a screw head, a drilling tail, a rod portion between the screw head and the drilling tail, and at least one first threads on the rod portion, wherein the helix angle at one end of each thread near the drilling tail becomes larger than the helix angle at other portion of the thread so as to form a guide thread section which covers a range not over half circle of the rod portion; and a distal end of the guide thread section is at an upper end of the drilling tail. There is one or two first threads. The screw with a drilling tail further comprises a second thread between the screw head and the at least one first thread.

A center or non-center cutting end mill for orbital drilling of fiber reinforced plastic (FRP) materials includes a shank, a neck, a cutting head and two or more flutes. The end mill has a tool geometry with the following features: a dish angle between about 2 degrees to about 6 degrees; a helix angle between about 5 degrees to about 18 degrees; an end teeth radial rake angle between about 0 degrees and about 15 degrees; a peripheral teeth radial rake angle between about 8 degrees and about 16 degrees; a gashing axial rake angle between about 3 degrees to about 10 degrees; and a primary clearance angle between about 10 degrees to about 18 degrees. The end mill is made from a tungsten carbide substrate with cemented cobalt in a range between about 3 to 10 wt. % and a diamond coating having a thickness in a range between about 8 to 20 μm.

The invention discloses a free-form surface micro-milling cutting force modeling method. The free-form surface micro-milling cutting force modeling method comprises the following steps of (1) obtaining machining parameters including the radius R of a cutter, a helix angle beta of the cutter, the number Nf of cutting edges, the feed amount ft of each tooth, an eccentric distance p of the cutter and the initial eccentric angle alpha of the cutter, (2) dispersing the cutting edges of the cutter in the axial direction to form a series of cutting micro-elements and obtaining cutting micro-elements involved with cutting, (3) calculating the instantaneous cutting thickness of the cutting micro-element P (k, phi) with an axial angle phi of the current cutting edge, (4) calculating the cutting force of the micro-element P (k, phi) and (5) calculating the sum of the parameters obtained in the steps (3) and (4) and the cutting forces of the micro-elements involved with cutting to obtain the cutting force of the cutter. By means of the free-form surface micro-milling cutting force modeling method, the micro-milling cutting force of a free-form surface can be efficiently and accurately predicted.

A transmission mechanism includes a first shaft connected to a first mounting plate; a second shaft connected to a second mounting plate; a first positioning plate through which the first shaft and the second shaft extend rotatably; a second positioning plate, through which the first shaft and the second shaft extend rotatably, spaced from the first positioning plate by a distance; a first gear mounted on the first shaft, disposed between the first positioning plate and the second positioning plate and having a first helical tooth portion; a second gear mounted on the second shaft, disposed between the first positioning plate and the second positioning plate and having a second helical tooth portion having the same tooth profile and helix angle with the first helical tooth portion ; and a middle gear disposed between the first gear and the second gear and having a transmitting helical tooth portion engaging the first helical tooth portion and the second helical tooth portion, wherein the middle gear rotates about an axis skewed with the first shaft and the second shaft.

The present invention relates to technical field of magnetic transmission in mechanical engineering, particularly a high temperature resistant high performance tapered slot type rotor asynchronous magnetic coupling, which comprises an outer rotor with magnetism, a inner rotor without magnetism, separation sleeve, and adjustable magnetic pole piece with teeth; the outer rotor comprises an outer rotor basal body and magnetic pole; the magnetic pole forms a certain helix angle with axial cord; the inner rotor comprises a inner rotor basal body, a magnetic induction prime conductor and end rings; the magnetic induction prime conductor embeds in angular deep groove of the inner rotor basal body in helical shape; the separation sleeve covers the inner rotor and is set between the inner rotor and the outer rotor; the adjustable magnetic pole piece with teeth is fixed on the machine body and can be disposed inside or outside of the separation sleeve; the outer magnetic rotor forms an outer layer air gap with the adjustable magnetic pole piece; the inner rotor forms an inner layer air gap with the adjustable magnetic pole piece. The above structure is disposed on the inside and outside circular conical surface to form circular cone asynchronous magnetic transmission. The advantages of the invention are as following: high temperature resistant, smooth, steady and reliable transmission, high usage of permanent magnet and big transmitting torque of unit volume.

A method of designing rotors for a Roots blower comprising a housing having cylindrical chambers, the housing defining an outlet port (19). The blower includes meshed, lobed rotors (37,39) disposed in the chambers, each rotor including a plurality N of lobes (47,49), each lobe having first (47a,49a) and second (47b,49b) axially facing end surfaces. Each lobe has its axially facing surfaces defining a twist angle (TA), and each lobe defines a helix angle (HA). The method of designing the rotor comprises determining a maximum ideal twist angle (TA_M) for the lobe as a function of the number N of lobes on the rotor, and then determining a helix angle (HA) for each lobe as a function of the maximum ideal twist angle (TA_M) and an axial length (L) between the end surfaces of the lobe.

To correct the tooth profile error of a ground gear, the wheel angle of a threaded grinding wheel is modified by dressing the threaded grinding wheel by a dressing device. To correct the helix form deviation of a ground gear, namely, to modify the helix angle of the gear, synchronization between the moving motion in the Z-direction of the threaded grinding wheel and the rotary motion of a table for installation of the gear is adjusted. When the helix form deviation is corrected by adjustment of the synchronization, a tooth profile change inevitably occurs. In consideration of the tooth profile change, correction of the tooth profile error by dressing is made.

A kneading disk has a plurality of disk elements having flight tips arranged at a helix angle E in a direction supporting main streams of a resin. The flight tips of every two adjoining disks have a clearance formed therebetween. The resin is kneaded by undergoing dispersion and distribution without having any excessive temperature elevation in approximately three kinds of streams, i.e. its main streams flowing along the flight tips, its back streams through the clearances and its tip riding streams flowing over the flight tips.

Helical gears, which are provided for a sun gear, planet gears, and an internal gear, have helix angles θ of not less than 25 degrees and not more than 45 degrees. Pawls provided for lock sections and internal gear lock receiving sections of the internal gear have rising angles γ, respectively, that satisfy the relational expression, 0≦tan γ<(η·di)/{dp·tan(90−α)}, wherein α is the helix angle of the sun gear, η is the screw efficiency of the sun gear as a sliding screw, dp is the pitch circle diameter of the sun gear, and di is an outer diameter of the internal gear defining a center of application of torque of the pawls.

A shell and tube heat exchanger, such as a vertical combined feed/effluent heat exchanger (VCFE), including: a shell having a fluid inlet and a fluid outlet; a plurality of baffles mounted in the shell to guide the fluid into a helical flow pattern through the shell; wherein a helix angle α of a baffle proximate the inlet is different than a helix angle β of a baffle proximate the outlet.

The invention relates to a design method used for transmitting DC high-temperature superconducting cable body coaxially and bidirectionally, belonging to the field of power system transmission and transformation; the design method comprises the steps as follows: according to the mechanical characteristic and the radius of enwinding framework of the superconducting strips, parameters of the superconducting cable body such as the enwinding helix angle and the enwinding pitch are determined; the magnetic field distribution of all layers of superconducting cable body are determined according to the operation current, thus determining the critical current on all layers of the cable; according to the critical current and the operation redundancy, iterative calculation is carried out for operation current and the magnetic field, thus finally gaining the critical current, best operation current, enwinding layer number and number of the cables. The designed superconducting cable body increases no enwinding process difficulty and achieves bidirectional transmission of DC current; the utilization ratio of the superconducting strip critical current reaches more than 90%; the quantity and low-temperature heat loss of the superconducting cable low-temperature container are respectively reduced by half. The design method has the advantages of large transmission capability, no loss, compact structure, certain current limiting capability, stable mechanical structure, self-shielding, no electromagnetic interference and the like.

A cutting tool having a shaft with a longitudinal axis, wherein the cutting tool includes a first flute extending about the longitudinal shaft along a helix angle and a first cutting edge adjacent the first flute. The cutting tool also includes a second flute extending about the longitudinal shaft along a helix angle and a second cutting edge adjacent a second flute. The cutting tool further includes a third flute extending about the longitudinal shaft along a helix angle and a third cutting edge adjacent the third flute. The first cutting edge, the second cutting edge, and the third cutting edge are unequally angularly spaced from each other.

The invention provides a five-shaft milling method for a complex curved surface. The method selects a hard uncoated milling-cutter with 0.2-0.8 [mu]m ultrafine or microfine particulars, wherein the milling-cutter uses a conical or tapered-conical structure with a cutter teeth Z of 3-5 blades, a helix angle beta of the blades is more than or equal to 45 DEG, a length to diameter ratio of the cutter D/L is less than or equal to 15, climb milling is used, cutting action of the cutter pulls the cutter to cut, a cutting-in point and a cutting out point of a cutter path are arranged outside the curved surface, the cutter path is along an arc tangent direction when workpieces are cut in or cut out, directions of the cutter path are changed outside the curved surface, a distance of the cutter path away from the curved surface is not less than 1 to 4 times of a tool diameter D; during processing, a tool feed amount Fz is less than or equal to 0.11-0.5 mm, a cutting speed V is 17-260 m/min; during a rough machining and a fine finishining, different cutting depths are selected, the fine finishining need a reserved amount of 2-0.7 mm; and oil gas spray of compressed air is used to cool and lubricate.

A rack-and-pinion steering apparatus comprises pinion teeth formed according to proper tooth specifications in other aspects under a larger pressure angle, thereby stably offering smooth and comfortable steering feeling over a long time. The module (m), number of teeth (z), tooth depth(h) and helix angle (β) of the pinion teeth (4) are set within the following ranges, under a pressure angle (α) set within a range of 24° to 30° and a given stroke ratio.

• • module (m): 1.8 to 2.0
  • number of teeth (z): 7 to 13
  • tooth depth (h): 2 m to 2.5 m
  • helix angle (β): 350 or smaller

It is an object of the present invention to effectively suppress the occurrence of burrs in machining of a fiber-reinforced composite material, etc., using an end mill. An end mill includes first cutting edges 4 which spiral in a direction defining a positive helix angle and second cutting edges 5 which spiral in a direction defining a negative helix angle, the first cutting edges 4 and the second cutting edges 5 being disposed at positions shifted in a circumferential direction. The first cutting edges 4 and the second cutting edges 5 are each configured to be continuous over an effective cutting edge length, and at a tool top, a phase angle P1 between one of the first cutting edges 4 and its adjacent second cutting edge 5 located toward the back in a tool rotation direction is set to be different from a phase angle P2 between the second cutting edge 5 and its adjacent first cutting edge 4 located toward the back in the tool rotation direction.