Pressure angle

About: Pressure angle is a research topic. Over the lifetime, 1373 publications have been published within this topic receiving 10245 citations. The topic is also known as: angle of obliquity.

Teaching instrument with cam mechanism

Abstract: The invention relates to a teaching instrument with a cam mechanism. The teaching instrument comprises a rotatable cam fixed on a rack, a circular drawing board and a pressure angle indicator, wherein a roller is tightly clung on the outline of the cam; the roller is in threaded connection with a driven rod; a fine rod is arranged beside the driven rod in parallel; the driven rod can axially move relative to the fine rod through a plurality of lever sets. The teaching instrument with the cam mechanism adopts a modularized design, can realize replacing forms of the driven rod roller, a flat head and a tip head, indicating the pressure angle of the driven rod, drawing a displacement curve of three driven rods, changing the cam centering and offsetting position, drawing a cam curve through a reversal method, and indicating a stroke angle of the cam. The teaching instrument solves the defects that a teaching instrument with two large cam mechanisms is high in cost, large in size, large in weight and single in function, is relatively small in weight and size, convenient to carry, simple to manufacture, low in cost and suitable for large-area popularization.

A novel design for enhancing the surface durability of the spur gear systems

Abstract: In this study, a general mathematical model for defining the gear tooth profile and its geometrical aspects that meet a desirable sliding contact during the meshing cycle is built. This model is based on the path of contact shape predefinition. In the contact path, a straight-line segment through the pitch point and a universal transition curve for the other segments are combined to create a free-form tooth profile with desired radius of curvature in the designed gear. The maximum pressure angle during the meshing cycle and the involute curve length parameter are only introduced to characterize this model. The designed gear in this study is given the title “free-form-gear” since it provided a universal manner of establishing the path of contact that provides desirable sliding conditions during the meshing cycle. The proposed tooth form, interference condition, contact ratio, contact stress, sliding coefficient, and meshing efficiency are derived and investigated in this study. The fillet stress and torsional mesh stiffness of the proposed gear pair are obtained using the finite element method (FEM). The performance of the new gear is compared to that of the standard involute and non-involute gear types. The results indicated that the method proposed in this study can be utilized to construct a gear pair with higher surface durability and strength than typical involute gear of the same size.

Automatic tool replacing device

Abstract: PROBLEM TO BE SOLVED: To prevent abrasion of a ball of a speed reducer and uneven distribution of pressing force in the shaft direction, by reducing a load when rotatingly driving a turret, in an automatic tool replacing device SOLUTION: The speed reducer for driving the turret in this automatic tool replacing device, is constituted by superposing a driving plate 5a, a cage 5b and a driven plate 5c in this order A recess-projection-shaped ball groove 6c of a frequency equivalent to a tool number is formed on the driven plate 5c attached with a tool The driving plate 5a is provided with the ball groove 6a for transferring a two period quantity by expanding the ball groove 6c of the driven plate 5c in the angle direction A plurality of guide holes 6b are arranged in the radial direction in the cage 5b, to respectively hold balls 5d The driving plate 5a is rotated by rotation of a main spindle, and the driven plate 5c is driven by reducing a speed to (the tool number/2) via the balls 5d The ball groove 5c of the driven plate 5c is set to an optimal pressure angle, and the load can be reduced The balls 5d are dispersed, and pressure in the shaft direction is uniformized, and the abrasion of the balls and the ball groove can be reduced COPYRIGHT: (C)2006,JPO&NCIPI

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.

Do angles of obliquity apply to 30° scattered radiation from megavoltage beams?

Abstract: The angle of obliquity is used in radiation shielding calculations to account for the longer path length x rays will see when obliquely incident on the protective barrier. According to the National Council on Radiation Protection and Measurements (NCRP), use of the angle of obliquity is explicitly assumed for primary radiation, so that an angle of obliquity for secondary radiation is never addressed. However, in the example section of the latest report, it specifically recommends against using an angle of obliquity for scattered radiation. To check this assumption, the existence or not of an angle of obliquity for scattered radiation has been investigated for bremsstrahlung x-ray beams of 4, 6, 10, 15, and 18 MV and for barriers consisting of concrete, lead, and steel using a Monte Carlo approach. The MCNP Monte Carlo code, v4.2C, has been used to generate scattered radiation at 30 degrees from a water phantom and incident on a secondary barrier at the same angle relative to the normal to the barrier. The barrier thickness was increased from zero to a thickness sufficient to reduce the fluence (f4 tally) to <10(-3). A transmission curve was created for each energy-barrier material combination by normalizing to zero thickness. The results for the first tenth-value layer (TVL) in concrete (5 energies) show an average angle of obliquity of 21.7 degrees +/- 5.6 degrees , and for the first two TVLs averaged 29.7 degrees +/- 3.9 degrees . The results for the first TVL in lead (3 energies) show an average angle of obliquity of 27.7 degrees +/- 4.0 degrees , and for the first two TVLs averaged 20.5 degrees +/- 5.8 degrees . There are no data in the NCRP reports for 30 degrees scattered radiation attenuated by steel with which to make a comparison.