Showing papers on "Pressure angle published in 1997"

Evolution of the angle of obliquity of the femoral diaphysis during growth--correlations.

Abstract: Numerous studies of the bicondylar angle of the adult femur have been carried out in human anatomy, paleoanthropology and primatology. The aim of this paper is to study the evolution of this angle in relation to age and acquisition of walking in young children. Seventy-seven radiographs of children, ranging from 5 months to 17 years postnatally, and of four dead newborn were analysed. The measurements concern the bicondylar angle (A.O.F.), the collo-diaphyseal angle (A.C.D.), the length of the femoral neck (L.N.) and of the femur (L.F.) and the interacetabular distance (D.I.A.). Some children were x-rayed at different ages, which permits a longitudinal as well cross-sectional study. The results show that there is no sexual dimorphism and that the increase in the angle is closely related to the age of the child. The bicondylar angle starts at 0° at birth and then increases progressively with growth to reach adult values of at least 6°-8° between 4 and 8 years postnatally. In adults, the mean values are between 8° and 11° and the maximum range is between 6° and 14°. The obliquity angle corresponds to an angular remodeling of the femoral diaphysis, which is independant of the growth and shape of the distal femoral epiphysis. The tibio-femoral angle measures the evolution of a physiologic phenomenon, from the load “in varus” to the load “in valgus” of the lower limb. It is linked with the bicondylar angle but is different from it.

Method of grinding the teeth of spiral-toothed bevel gear wheels

Abstract: Disclosed is a method of grinding bevel gear teeth in an intermittent indexing process using a single grinding wheel provided with different bevel angles (α) to produce the desired grinding wheel radii (R): one flank is machined during grinding in downward generation as far as a first turning point, another flank is produced in upward generation as far as a second turning point, and machine settings are so adjusted in the turning points as to ensure a correct pressure angle and correct flank topography during the generating process, irrespective of the different bevel angles (α). The process combines the advantages of the known completing process, by which both flanks can be ground at the same time at the cost of imposing a particular wheel body geometry with conical teeth, with those of the known two-track process for grinding both flanks with a double grinding head, by which various additional correction factors can be introduced to optimize the flank shape for convex and concave flanks.

Work inclination angle measuring method, work bend angle measuring method, work inclination quantity measuring instrument and work bend angle measuring instrument

Abstract: PROBLEM TO BE SOLVED: To conduct bending through precise bend angle detection by precisely measuring an inclination angle and automatically correcting this inclination angle even when the bend angle is detected at one side in bending work of a sheet metal. SOLUTION: A position of flanges in front/rear of a work bent is detected by position sensors arranged in the front/rear, both sides of the work, bend angles are respectively measured based on these detected values, based on measured angles, an inclination angle of the work is obtained. In the bending, after the work is bent, an angle is measured by a position sensor arranged in the front or the rear of the work. Based on the measured angle and the obtained inclination angle of the work, a bend angle of the work is obtained. COPYRIGHT: (C)1998,JPO

Measurement of Helical Gear Using Coordinate Measuring Machine.

Abstract: A method for inspecting a helical gear using a coordinate measuring machine (CMM) is proposed. In the method, the coordinates of a large number of points on the tooth surface of the gear are measured at random using a CMM. The method is based on the idea that the pitch error, profile error, pressure angle error, and spiral angle error can be calculated from the measured coordinates because the information on various errors of the gear is included in the measured coordinates. For calculation of each error, the tooth surface is described as a function of each error item and then the values for the items are estimated from all of the measured coordinates by the method of least squares. The difference between the estimated value for the item and the corresponding design value is the error of the item. From the results of experiments, it is clarified that each error of a helical gear can be estimated using a widespread CMM instead of a specially designed measuring machine for gears.

Graphic processor for gear

Abstract: PURPOSE: To provide a gear graphic processor capable of simply preparing an involute gear, preparing a gear with a concrete shape followed by the involute gear, accurately and simply preparing the gears while visually checking their engaged state, and to easily designing an involute spur gear with suitable strength based upon strength analysis and reasonable cost. CONSTITUTION: This gear graphic processor 10 is provided with a gear curve preparing means for computing circular arc gear thickness ss , si passing respective equially divided points (i) obtained by equally dividing between a gear bottom circle radius rb and a gear top circle radius rk into n parts based upon the number Z of gears, a reference pressure angle αs , a module (m), an addendum modification coefficient (x), the radius rb , and the equal division number (n) to be gear elements inputted to an input means 13 and finding out a curve successively and smoothly connecting respective tips of these (n+1) circular arc gear thickness ss , si .

Triaxial gearing and gearing

Abstract: PROBLEM TO BE SOLVED: To suppress the fluctuation of a mesh transmission error, the fluctuation of relative relation of' a gear pair, so as to reduce vibration and noise. SOLUTION: In a triaxial gearing provided with a uniaxial gear and a triaxial gear respectively meshed with a biaxial gear, the gear tooth modifying quantity is determined on the basis of a mesh pressure angle and a helix angle of a base circle in addition to a parallelism error and a stagger error between shafts meshing with teeth. The tooth surface modifying quantity is maximum at the middle 73 from one end 71 of a modifying range to the other end 72 in a face width direction and is minimum at one end 71 and the other end 72, and the modifying quantities at one end and the other end are different within a fixed range.

Design of Antibacklash Pin-Gearing

Abstract: The paper suggests that pin gearing can be used for an antibacklash gear. The gear tooth curve derived from a cycloidal curve furnishes the pin gearing with kinematic antibacklash, low pressure angle, and no interference among other features. Pins on one side of a centerline are contacting the forward faces of a mating tooth gear. Simultaneously, pins on the other side of the centerline are contacting the backward faces of the gear. The correct center distance can be maintained in this multiple-contact mechanism by applying a force directed to each other center. A generating method of tooth-gear manufacture is also suggested. Contact and bending deformations as well as the gear stress are analyzed to help its design.

Sector gear for steering device and its manufacture

Abstract: PROBLEM TO BE SOLVED: To improve the gear profile of a sector gear, thereby enhance its forming and workability, and furthermore strengthen the whole of the sector gear including sector teeth SOLUTION: The sector gear 8 is formed out of sector gear raw material processed by forging as plastic working Each dedendum 7c at the sector tooth forming portion possesses each corner part 23 in a curved shape, and a portion 21 inclined along a pressure angle is continuously formed As machining works, each sector tooth is generated so as to be formed into a tooth flank shaped by an involute curve by cutting and grinding only the tooth flank to be meshed with a rack tooth only by a working margin Each dedendum and each addendum 7d are left as they are plastically processed with its forged raw material surface exposed

Mechanical clock with tourbillion mechanism

Abstract: PROBLEM TO BE SOLVED: To adjust the time accuracy strictly in a thin structure with a high degree of design freedom. SOLUTION: The mechanical clock is provided with a tourbillion mechanism which has a cage 1 loading a balance 7, a pallet 6 and an escape wheel 5 and rotating integrally with the parts. The cage 1 has a lower plate 10 having a gear 14 driven by a gear train formed in the outer periphery thereof. A pinion 3 formed coaxially with the escape wheel 5 is meshed with an internal gear 9 fixed to an earth plate 8. The escape wheel pinion 3 and the internal gear 9 are constituted to operate in a planetary gear movement, that is, to rotate and revolve the escape wheel 5 in accordance with the rotation of the cage 1. The cage 1 has an upper plate 12 with a pallet receptacle 16 supporting the pallet 6 in a swingable fashion, and the pallet receptacle 16 is constituted not to overlap, on a plane, a rim part 17 of the balance 7 axially supported by the lower plate 10 and upper plate 12. Teeth of at least the gear 14 formed in the outer periphery of the lower plate 10, the internal gear 19 and the escape wheel pinion 3 are formed by an involute of the same module and the same pressure angle.

Effects of Design Parameters on Root Stresses of Thin-Rimmed Helical Internal Gears with Asymmetric Web Arrangement in Mesh.

Abstract: This paper presents a study on the effects of design parameters (rim thicMness, standard pressure angle, number of teeth, and face width) on root stresses of a meshed thin-rimmed helical internal gear with an asymmetric web arrangement for a planetary gear unit of the automatic transmission of automobile. The tooth deflections of the thin-rimmed helical internal gear with an asymmetric web arrangement of various design parameters due to a concentrated load were calculated by the three-dimensional finite-element method (3D-FEM). On the basis of the calculated results, approximate equations for the influence function of the tooth deflection were derived. The load sharing factor and the load distribution on the contact line of the thin-rimmed helical internal gears in mesh were calculated using these approximate equations and Kubo and Umezawa's method. The root stress of the thin-rimmed helical internal gear under the distributed load was calculated using the 3D-FEM. and the effect of the design parameters on the root stress was determined. Furthermore, a practical formula for the maximum root stress of the thin-rimmed helical internal gear with asymmetric web arrangement in mesh was derived.

A Study on the Proper Scope for Pressure Angle, Ratio of Tooth Number & Radius of Curvature in Non-Circular Gears

Abstract: Non-circular gear has a good velocity ratio in high speed and heavy load without any slip, moreover, it can transmit various motion, using simpler structure than link and cam, automation mechainism. In case of designing and manufacturing non-circular gear. I suggest one of references in applying non-circular gear to industrial plant, and suitable range of application by pressure angle curvature and angle ratio

Synthesis of Cams with Ruled Surface Followers

Abstract: The curvature properties of ruled surfaces are derived. Several parameters are used to express the geometry of ruled surface explicitly. Using the ruled surfaces as generating surfaces, the equation of meshing is derived for a prescribed input-output relation. Considering the motion types of mechanisms and the particular ruled surfaces, the meshing equation is simplified. The pressure angle of the cam is analyzed as well as that of the follower, and the relation between these pressure angles is obtained using the equation of meshing. Two examples are given.