Showing papers on "Pressure angle published in 1981"

Helical screw rotor profiles

Abstract: The invention concerns helical- or screw-type driving and driven rotors having lands and intervening grooves for coacting engagement, within a housing of a machine, such as a gas compressor or expander, the rotors having improved, more efficient, profiles. The profiles are defined with contiguous elliptic and involute sections to improve the pressure angle, and the profiles are configured to define rotor-to-rotor sealing surfaces in closure of a compressed gas pocket in which, the pocket gas pressure always urges or torques the driven rotor in the positive or forward-rotary direction.

Method for forming splines in sheet metal

Abstract: A sheet metal blank is placed at the entrance of a die having a splined interior contour. A punch having a conjugate splined surface enters and passes longitudinally through the die. The splines are formed by passing the blank and punch through the die within an annular space whose contour defines the final spline configuration. Alternatively, preformed splines having a large pressure angle and full corner radii are reformed by multiple passes through dies whose configurations vary to produce shallow pressure angle splines and tight corner radii.

Combination mechanism of rack and pinion

Abstract: PURPOSE:To restrict a displacement caused by a slight rotation of a rack and its vibration by selecting the radius of a helical rack, a distance from the axis to the tooth end, a helix angle of the tooth and pressure angle to satisfy a specific expression. CONSTITUTION:This rack and pinion mechanism is applicable for a power steering mechanism in an automobile. When a helical gear 2 with a helix angle beta and a pressure angle alphan feeds in mesh a pinion (not illustrated) in the direction A and a rack in the direction B, a normal plane pressure Pn at a contact point S1 where the helical gear comes in mesh with a spiral gear not illustrated in the drawing acts in the direction S1C1. Therefore, the moment C in the counterclockwise direction is generated. When the mesh comes to a contact point S3, the moment D in the clockwise direction is formed. By determining the configuration of the rack 1 so as to satisfy the expression (LK represents the radius of the rack 1 and RK represents the distance from the axis 0 to the tooth end.), the clockwise and counterclockwise moments may become equal so that the required purpose can be attained.

Sprocket for silent chain

Abstract: PURPOSE:To prevent discordant sounds, noises from occurring by a method wherein tooth parts different in a pressure angle are arranged at random on sprockets for interlocking with a so-called silent chain made by overlapping and connecting toothed link plates. CONSTITUTION:Tooth parts T1.T2 which are drawn from a circle Dg1 smaller, a circle Dg2 larger than a base circle are mixed at random with the 1st tooth part to where its flank 7 comes in contact with a sprocket 1 on a datum engaging circle PC. On the PC circle, the pressure angle is large on T1 and small on T2. When the chain is being wound, the engaging points vary up and down and the bending angle of the chain changes and the engaging time varies. Since the engaging time becomes irregular, periodical sounds and resonance sounds are restrained, and additional tension is prevented from occurring, the life can be prolonged and the safety can be improved.

DESIGN, MANUFACTURING PROCESSES AND LOAD CAPACITY OF CYLINDRICAL GEAR PAIRS WITH 2 TO 4 PINION TEETH F0R HIGH GEAR RATIO : 1st Report, Design, Manufacture and Surface Durability of the Gear Pairs with 2 to 3 Pinion Teeth

Abstract: Practical design methods of cylindrical gear pairs with 2 to 4 pinion teeth for higher gear ratios were investigated to obtain higher load carrying capacities. Using a conventional hob with a pressure angle of 20°and a conventional hobbing machine with special made attachments, the authors designed and made test gear pairs with gear ratios of Z2/Z1=41/2 and 38/3. These gear pairs were tested beyond 10×106 pinion rotations using the power circulating gear-load-testing-machines made by the authors. The tooth surfaces of large gears were very likely to pit although the load cycles were appreciably smaller than those on the pinion teeth. It was clearly indicated that a gear with higher hardness than that of the mating pinion had a greater load carrying capacity. The test gear pairs produced much higher sliding due to greater profile shifting than that of gear pairs with numbers of pinion teeth of greater than six, but they showed a comparatively good efficiency of about 93% in the case when the test gear pairs with 3 pinion teeth were used under normal running conditions.

A Study on Strength of Toothed Belt : 6th report, Behavior of Belt and Pulley Tooth at Incomplete Meshing Region

Abstract: In this paper, the interference between belt tooth and pulley tooth at the incomplete meshing region of toothed belt drives is numerically calculated by using the analytical method mentioned in the 4th report, and the influence of the radius of the tip corner rounding and the pressure angle of belt and pulley tooth on the interference is discussed. Also, the authors discuss experimentally on the effect of the radius of the tip corner rounding of pulley tooth on the fatigue strength of L type polyurethane and polychloroprene rubber belt, and the displacement of the belt pitch line depending on the load and the frictional force acting on belt tooth at the incomplete meshing region. Further, the sliding velocity of the contacting point of belt tooth and pulley tooth is calculated and the total nominal stress at the bottom land corner of belt tooth is discussed.

Rack for splining thin-wall sleeves of power transmission members

Abstract: A toothed rack (22) disclosed has a toothed forming face (24) of a novel construction for forming splines (42) in a thin-wall sleeve (36) of a power transmission member (28) by meshing of the rack and a toothed mandrel (26) with the sleeve therebetween to form the splines. The toothed forming face has leading, intermediate, and trailing tooth groups (40a, 40b, 40c) that perform the splining. The pitch line tooth thickness of the leading tooth group is at least equal to and preferably greater than the pitch line tooth thickness of the trailing tooth group which has an addendum of a greater height than the leading tooth group. The teeth of the intermediate tooth group have an addendum height that is shorter than the teeth of the trailing tooth group and preferably equal to the addendum height of the leading tooth group. The pitch line tooth thickness of the leading tooth group is equal to and preferably greater than the pitch line tooth thickness of the intermediate tooth group. The profile of the intermediate teeth from the tip to the root thereof is the same as the profile of the trailing teeth from the tip thereof toward the root thereof for the same distance. All of the teeth have faces defining the same pressure angle as each other.

High speed geared transmission

Abstract: PURPOSE:To transmit a large power with a comparatively small bevel gear by setting a speed transmitting ratio to output shafts against an input shaft, a pressure angle between a driving bevel gear and a driven bevel gear, and an angle of torsion to be fixed values. CONSTITUTION:A speed transmitting ratio between bevel gears 6, 7 and bevel gears 16, 17, that is, a speed transmitting ratio to output shafts 10, 11 against an input shaft 2, is set to be 1.45-1/2.1. Also, an angle pressure alpha on teeth of the bevel gears 6, 7, 16, 17, an angle of torsion beta of teeth of the bevel gears 6, 7, 16, 17, and a pitch cone angle delta of the bevel gears 16, 17 are set to be within a range that is set by an equation, -0.324<=tanalpha.sindelta/cosbeta-tanbeta.cosdelta<=0.1.

Quenching process by laser

Abstract: PURPOSE:To provide an excellent quenching effect over the entire surface area by a method wherein two laser beams having a specified cross angle are projected onto the surface of the teeth base of a gear or rack so that the laser beams cross over them. CONSTITUTION:Two laser beams having a cross angle more than twice the pressure angle of teeth of a rack, etc. are used. In the case of a rack 10, for example, the rack 10 is being moved in the direction of the arrow 16, and two laser beams 12, 14 having the cross angle twice the pressure angle A are projected so that they cross each other on the base surface 18 of the teeth. In the state of (a), the teeth base surface 18 is quenched. In the state of (b), the left side is quenched. Moving to the teeth surface 22, the right side is started to be quenched at the state of (c). Sequential quenching thus continues. To provide laser beams with a specified angle, a laser beam 26 from an oscillator 24 is changed by an expander 28 in its diameter and formed into a parallel beam 32, which is handled by a division-mirror 34, a cylindrical concave mirrors 36, 38 so that laser beams 12, 14 cross over at the specified location. The process thus provides a quench operation over the entire surface area.

Asymmetric tooth form type involute screw gear

Abstract: PURPOSE:To enable to enhance the face pressure strength of the titled gear by a method wherein a driving gear of the titled gear is provided with a small diameter while a driven gear is provided with a larger diameter, and the respective top lands are equal to those of symmetric tooth form. CONSTITUTION:In the driving gear 10 and the driven gear 20, the pressure angle of coast-side tooth surfaces 12, 22 of the symmetric tooth form indicated by solid lines is made to be smaller than the pressure angle of drive-side tooth surfaces 11, 21, whereby the asymmetric tooth form is obtained wherein normal-to-axis tooth thicknesses t'S1, tS2 are not changed while normal-to-axis top lands t01, t'02 are increased, as indicated by two-dotted lines. The increment of the normal-to-axis top land of the driving gear 10 is converted into a change of the thickness on the pitch circle of the gear 10, and the converted value is added to the tooth thickness of the driven gear 20. ACcordingly, the driven gear 20 having the normal-to-axis tooth thickness tS2, an outside diameter D02 and a normal-to-axis top land t02 as indicated by broken lines and the driving gear 10 of an outside diameter D01 meshed with the gear 20 are obtained.

Rotor for screw compressor

Abstract: PURPOSE:To provide forward and backward flank surface of a female rotor at its concave with pressure angles and the convex of a male rotor with a pressure angle by forming it in a tooth shape determined by the concave of the female rotor, in order to make their hobbing easy. CONSTITUTION:A primary portion 9-10 of a forward flank surface 7 is formed in a cycloid tooth shape defined by the convex 6 of a male rotor 2 at one point on its top and secondary portions 10-11 and 13-14 adjacent to the forward flank surface 7 and a backward flank surface 8 are formed in a circular tooth shape with the central point 21 of their circular arcs positioning inside the pitch circle 16 of the female rotor 1. The radius of this circular arc is made larger than an addendum outside the pitch circle 16 of the female rotor 1. Pressure angles thus provided to the forward and backward flank surfaces 7 and 8 and the convex 6 of the male rotor 2 make hobbing by both rotors 1 and 2 easy.

Vehicle acceleration sensor for emergency locking type take-up device

Abstract: PURPOSE:To obtain an acceleration sensor of high response characteristics and less hysteresis phenomena by incorporating a prescribed shape of an inertia body rolling on the top surface of an inclined supporting table in accordance with accelerations and by other things. CONSTITUTION:An inertia body 12 provided with an horn part 12b of a shape which is freely penetrated through the through-hole 16 of a supporting table and permits sliding movement without any interference in accordance with accelerations oscillates by the angles corresponding to the accelerations and the accelerations are detected by an actuator 13 of a small pressure angle with respect to the inertia body 12 interlocking thereto. The inertia bottom surface 12a of this inertia body 12 assumes a spherical shape centering at the center of gravity of the inertia body 12 and resets with good stability by contacting the inclined supporting surface of the required wedge angle of a table 11. By this constitution which is hard to receive the effect of frictional force, has less dynamic and static directivities and is good in stability, the vehicle acceleration sensor for the purpose of emergently locking a take-up device of a sheet belt, etc. of high responsive characteristics and less hysteresis phenomena is obtained.