Showing papers on "Pressure angle published in 2014"

High efficiency gears synthesis by avoid the interferences

Abstract: The paper presents an original method to determine the efficiency of the gear, the forces of the gearing, the velocities and the powers. It is analyzing the influence of a few parameters concerning gear efficiency.These parameters are:z1 - the number of teeth for the primary wheel of gear; z2 - the number of teeth of the secondary wheel of gear; alpha0 - the normal pressure angle on the divided circle; beta - the inclination angle. With the relations presented in this paper, it can synthesize the gear’s mechanisms. Today, the gears are present everywhere, in the mechanical’s world (In vehicle’s industries, in electronics and electro-technique equipments, in energetically industries, etc). Optimizing this mechanism (the gears mechanism), we can improve the functionality of the transmissions with gears. At the gear mechanisms an important problem is the interference of the teeth. To avoid the interference between teeth, we must know the minimum number of teeth of the driving wheel, in function of the pressure angle (normal on the pitch circle, alpha0), in function of the tooth inclination angle (beta), and in function of the transmission ratio (i).

Parametric investigation of the combined effect of whole depth and cutter tip radius on the bending strength of 20

Abstract: Standard 20 ◦ spur gears are typically generated with a whole depth of 2.2-2.25 times the module. At the nominal centre distance, this leaves a radial clearance, which is in itself redundant from a functional point of view. However, the intrinsic geometry of the cutting process always results in a non-involute root profile (the trochoid), which is even more pronounced in the case of using a rounded cutter tip in order to increase the strength of the cutting edge. Larger tip radii produce stronger tooth fillets, potentially increasing the bending strength, but reducing the involute part of the tooth. Thereby, they increase the risk of interference with mating gears. This paper performs a parametric investigation of the combined effect of the cutter radius and the dedendum on the clearance and the resulting tooth bending strength using analytical calculations, computerised generation and finite element simulations to determine the exact tooth geometry in search of stronger tooth forms. Non-dimensional modelling is used to obtain results applicable to entire gear families. List of symbols αo Pressure angle

A Novel Finish Hobbing Methodology for Longitudinal Crowning of a Helical Gear With Twist-Free Tooth Flanks by Using Dual-Lead Hob Cutters

Abstract: In the gear finish hobbing process, to obtain a twist-free tooth flank of helical gears, a novel hobbing method for longitudinal crowning is proposed by applying a new hob’s diagonal feed motion with a dual-lead hob cutter. Wherein the hob’s diagonal feed motion is set as a second order function of hob’s traverse movement and tooth profile of hob cutter is modified in a dual-lead form with pressure angle changed in it’s longitudinal direction. The proposed method is verified by using two computer simulation examples to compare topographies of the crowned work gear surfaces hobbed by the standard and dual-lead rack cutters. The results reveal the superiority of the proposed novel finish hobbing method.Copyright © 2014 by ASME

Influence of deflection hole angle on effusion cooling in a real combustion chamber condition

Abstract: Fluid-solid coupling simulation is conducted to investigate the performance of effusion cooling in the real combustion chamber condition of strong rotation and primary holes. The wall temperature and film cooling effectiveness of different deflection angle is analyzed. From the results, it is concluded that the performance of effusion is better than conventional film cooling. The wall temperature and gradient is lower, the cooling efficiency is higher and the coolant is reduced by 20%, but pressure loss is slightly increased. The cooling effectiveness decreases behind primary holes because of local combustion. Comparison with the effect of deflection angle, the cooling performance of 60 deg deflection angle is best. The coolant is better attached to the wall downstream when the deflection angle is same as the rotating mainstream. In addition, the effect of deflection angle is not so significant on the coolant flow rate, but a large negative impact on the pressure loss. Although the cooling effectiveness of 60 deg deflection angle is highest, the total pressure recovery coefficient is lower. The maximum temperature drops about 70K and the outlet temperature distribution trends more consistent. So various factors should be taken into consideration when designing of deflection angle.

Vibration analysis of an influence of groove in the bottom land of a spur gear

Abstract: Modern machinery and manufacturing systems are committed to be more accurate and punctual in delivery, which in turn requires a perfect machining and maintenance system. Maintenance has many indispensable tasks, of which vibration control is one of the most challenging for maintenance engineers. Majorly in rotating machinery like gears and turbines, vibration is the predominant factor to be controlled. Hence this paper deals with a novel way of controlling the vibration in spur gears. Generally gear vibrations can be reduced by profile modification or by decreasing the pressure angle or dynamic load and also by means of increasing the contact ratio. In this work, a profile modification is considered. A groove has been generated at the bottom land of the gear in order to increase the thickness and height of the gear tooth at the root. Due to this, the stiffness of the gear tooth at the bottom land of the gear increases which in turn reduces the radial load deflection and the vibration amplitude in the vert...

Precise design and profile modification method for asymmetric gear

Abstract: The invention relates to a precise design and profile modification method for an asymmetric gear. The method comprises the following steps that S1, the tooth profile equation of a rack tool is obtained according to the structure of the rack tool; S2, coordinate transformation is carried out on the tooth profile equation of the rack tool according to the movement rule of the rack tool to obtain a rack tool equation under a gear coordinate system; S3, a meshing equation is obtained according to the meshing rule of the rack tool and the gear; S4, the tooth profile equation of the asymmetric gear is determined according to the rack tool equation and the meshing equation; S5, three-dimensional modeling is carried out according to tooth profile data. The profile modification method directly carrying out pressure angle profile modification on the rack tool is disclosed, the tool after the profile modification can directly carry out machining to obtain the formed gear having the involute modified, the gear machining efficiency is improved, and the obtained formed gear through the profile modification is simple and practical.

A Novel Method for Calculation Gear Tooth Stiffness for Dynamic Analysis of Spur Gears With Asymmetric Teeth

Abstract: Recently, there have been a number of research activities on spur gears with asymmetric teeth. The benefits of asymmetric gears are: higher load capacity, reduced bending and contact stress, lower weight, lower dynamic loads, reduced wear depths on tooth flank, higher reliability, and higher efficiency. Each of the benefits can be obtained through asymmetric teeth designed correctly. Gears operate in several conditions, such as inappropriate lubrication, excessive loads and installation problems. In working conditions, damage can occur in tooth surfaces due to excessive loads and unsuitable operating conditions. One of the important parameters of the tooth is stiffness, which is found to be reduced proportionally to the severity of the defect by asymmetric tooth design as described in this paper. The estimation of gear stiffness is an important parameter for determining loads between the gear teeth when two sets of teeth are in contact. In this paper, a 2-D tooth model is developed for finite elements analysis. A novel formula is derived from finite element results in order to estimate tooth stiffness depending on the tooth number and pressure angle on the drive side. Tooth stiffness for spur gears with asymmetric teeth is calculated and the results were compared with well known equations in literature.Copyright © 2014 by ASME

Design Method of Internal Rotary Gear Pump by Parameterized Line Conjugated Tooth Profile

Abstract: Aiming at the design of line conjugated internal rotary gear pump tooth profile, the model of solving conjugated profile point by tooth profile normal reversal method is established. The methods of solving sliding ratio, meshing angle and pressure angle through meshing line are built. The influence on the pump transmission performance by the distance parameter l is shown. The intact tooth profiles construction method by tooth thickness-parameter k is built, the condition of profile overlap interference and the solution of the interference between addendum and dedendum is given. The models of flow pulsation and trapping is proposed. The results of performance simulation show that this kind of pump have advantages of low flow pulse and hard to trap oil. A design method is provided for system solution of the tooth profile design of line conjugated internal rotary gear pump.

Piston type hydraulic pump with crank connecting rod structure

Abstract: The utility model discloses a piston type hydraulic pump with a crank connecting rod structure. The piston type hydraulic pump with the crank connecting rod structure comprises two plungers, wherein the plungers are arranged in a containing cavity, two air cylinders are arranged along a straight line, a connecting rod is connected with pistons of two driving mechanisms, two racks are arranged on the connecting rod in the length direction of the connecting rod, two gears meshed with the racks respectively are further arranged on a machine tool, each plunger is connected to the eccentric position of the corresponding gear through a hinge rod, and the hinge rods are hinged to the gears and the plungers. The piston type hydraulic pump with the crank connecting rod structure has the advantages that work of two plunger hydraulic pump bodies is achieved just through one symmetrical rack-and-gear air cylinder structure, the working efficiency is high, and economical efficiency is good; the air cylinders are used for driving, and thus the environment is not polluted; a crank connecting rod mechanism is a non-linear mechanism, the crank connecting rod mechanism is a stroke enlargement mechanism when a drive angle and a pressure angle are large, and the hydraulic pump can output low-pressure large-flow liquid; the crank connecting rod mechanism is a force enlargement mechanism when the drive angle and the pressure angle are small, and the hydraulic pump can output high-pressure small-flow liquid.

Effects of pressure angle and tip relief on the life of speed increasing gearbox: a case study.

Abstract: This paper examines failure of helical gear in speed increasing gearbox used in the wind turbine generator (WTG). In addition, an attempt has been made to get suitable gear micro-geometry such as pressure angle and tip relief to minimize the gear failure in the wind turbines. As the gear trains in the wind turbine gearbox is prearranged with higher speed ratio and the gearboxes experience shock load due to atmospheric turbulence, gust wind speed, non-synchronization of pitching, frequent grid drops and failure of braking, the gear failure occurs either in the intermediate or high speed stage pinion. KISS soft gear calculation software was used to determine the gear specifications and analysis is carried out in ANSYS software version.11.0 for the existing and the proposed gear to evaluate the performance of bending stress tooth deflection and stiffness. The main objective of this research study is to propose suitable gear micro-geometry that is tip relief and pressure angle blend for increasing tooth strength of the helical gear used in the wind turbine for trouble free operation.

Synthesis of the base curves of non-circular gears via the return circle

Abstract: The subject of this paper is the synthesis of the base curves of non-circular gears by means of the Aronhold theorem and the return circle. The base curves can be generated in several ways, as reported in the literature, but this approach comes from the kinematics fundamentals; it is, thus, more comprehensive and useful. In particular, the base curves are obtained by intersecting at each pitch point, the corresponding return circle with the line of action for a given pressure angle.

Preliminary modeling of the oil trapping between teeth for spur gears

Abstract: This study focuses on the phenomenon of oil trapping in the tooth spaces of spur gears. It presents the first obtained results in order to provide an estimation of the power losses due to the compression of the oil trapped between the inter teeth meshing spaces in a high-speed transmission for internal and external spur gears. It first allows, to model the inter teeth spaces at any time and offers limits for the trapped fluid volume and axial and radial discharge surfaces. The discretization impact result is discussed.Then, the influence of certain design and operating parameters such as module, pressure angle, addendum modification coefficient and rotational speed on these discharge surfaces and trapped volume is presented.

Pre-grinding hob for machining micro-segment gears

Abstract: The invention relates to a pre-grinding hob for machining micro-segment gears. A cutting edge normal tooth profile of the pre-grinding hob comprises a main cutting edge segment, an addendum arc segment and a characteristic curve connecting segment, the main cutting edge segment is a normal engagement contacting tooth profile curve segment for machining the micro-segment gears, micro-segment curved lines or micro-segment straight lines are smoothly connected to form the main cutting edge segment, the length of the main cutting edge segment is not larger than 1 micrometer, the characteristic curve connecting segment is a connecting curve segment of a pre-grinding hob tooth addendum arc segment and a micro-segment tooth profile segment, and the trend and the length of the characteristic curve connecting segment are related to the modulus, the initial pressure angle, the pressure angle increment, the grinding allowance, the distribution form of the grinding allowance and the like of the micro-segment gears to be machined. The high-precision micro-segment gears can meet specific use requirements and mass production conditions as far as possible according to theoretical calculation and experience of the trends and the lengths of an undercutting arc segment and a characteristic transition curve segment.

Проектирование и анализ кулачковых механизмов с помощью ЭВМ

Abstract: To reduce energy consumption in mechanisms and machines, it is necessary to develop mathematical models that can be used at the initial design stage. One of the most important design problems is that numerous quality criteria depending on speed and load must be taken into account. It is especially difficult to deal with the criterion of mechanism efficiency. In this paper, the dependence of the cam gear efficiency on the pressure angle is investigated. This criterion was studied using a computer on the basis of the developed mathematical model, which provided new previously unknown results. When performing graphic calculations, the pressure angle was recommended to reduce in order to reduce the frictional forces. Mathematical modeling showed that the instantaneous efficiency of the cam gear increases with the pressure angle. This study makes it possible to improve the calculation of the cam gear in course design in the theory of mechanisms and machines.

Dynamic surface wear characteristics in spur gear transmission system with dynamic loads and wear coefficients

Abstract: In order to reveal the characteristics of gear surface dynamic wear and the effect of parameters in gear transmission system, the equations of motion with nonlinear backlash, internal error excitation and time-varying mesh stiffness, which was calculated by employing Weber–Banaschek formula, were built to obtain the distribution of dynamic loads along the line of action for involute gear The minimum oil thickness at current gear teeth contact point and the gear teeth surface roughness were utilized to acquire the expression of dynamic surface wear coefficients The discretization of involute gear profile was conducted by dividing the current pressure angle increment between the first mesh point and final mesh point equally The tooth wear equation proposed by Flodin was introduced and the discrete dynamic surface wear model was established to simulate the wear process for an engaging gear pair under certain system parameter settings The results show that the accumulated surface wears are distributed along the involute gear profile unequally with maximum wear at tip point and minimum wear at pitch point respectively under the influences of dynamic loads, dynamic wear coefficients and relative sliding velocities The accumulated surface wear of pinion is more serious than that of the gear and this phenomenon is validated by engineering practice There exist relatively sensitive regions of gear surface accumulated wear while the transmission ratio and gear module are varied

Method for machining worm-gear pair

Abstract: The invention relates to a method for machining a worm gear through a standard gear hob and machining a worm meshed with the worm gear through a turning tool. According to the technical scheme, the standard gear hob is selected, wherein the nominal modulus and the pressure angle of the standard gear hob are equal to the nominal modulus and the pressure angle of the worm gear to be machined, the diameter of the standard gear hob is larger than that of the worm meshed with the worm gear to be machined, and the axial length of the standard gear hob is larger than the rim width of the worm gear to be machined; the standard gear hob is placed perpendicular to the end face of the worm gear to be machined, wherein the standard gear hob and the worm gear to be machined are kept connected in the radial direction, and the spiral line directions are approximately the same; then, the standard gear hob is rotated by an angle theta, so that the spiral line of the standard gear hob and the spiral line of the worm gear to be machined completely coincide. When a single-start worm is machined, the modulus mc and the pressure angle alpha c of the turning tool are equal to the nominal modulus m0 and the pressure angle alpha0 of the worm respectively; when a multi-start worm is machined, the following relation between the modulus mc and the pressure angle alpha c of the turning tool and the nominal modulus m0 and the pressure angle alpha0 of the worm is met.

Involute gear tooth profile gear cutting equipment and gear cutting method thereof

Abstract: The invention discloses involute gear tooth profile gear cutting equipment which comprises a gear hobbing machine tool and a gear grinding machine tool. The gear hobbing machine tool is provided with a rough machining hobbing cutter, the gear grinding machine tool is provided with a first grinding wheel and a second grinding wheel, a tooth profile angle a1 of the first grinding wheel is smaller than a pressure angle a of a gear to be machined, and a tooth profile angle a2 of the second grinding wheel is equal to the pressure angle a of the gear to be machined. The method includes the steps of a), rough gear hobbing; b), gear grinding by the first grinding wheel; c), gear grinding by the second grinding wheel; d), heat treatment and finish machining; e), fine gear grinding. By the application of the involute gear tooth profile gear cutting equipment and a gear cutting method thereof, and hardened face gears meeting all kinds of pressure angle and pre-grinding amount requirements can be machined without specially purchasing a convex angle pre-grinding hobbing cutter, so that development time of new products is shortened, and cost for purchasing the hobbing cutter is saved.

Crank connecting rod transmission type hydraulic pump with linear motor

Abstract: The invention discloses a crank connecting rod transmission type hydraulic pump with a linear motor. The crank connecting rod transmission type hydraulic pump comprises at least one plunger piston which is movably arranged in a cavity. The crank connecting rod transmission type hydraulic pump is characterized by further comprising the linear motor, at least one rack is arranged on the motor secondary level of the linear motor, and at least one gear is meshed with the rack; the plunger piston is connected to the eccentric position of the gear through a hinged rod, and the hinged rod is hinged to the gear and the plunger piston. According to the crank connecting rod transmission type hydraulic pump with the linear motor, a crank connecting rod mechanism is fully utilized, when the transmission angle and the pressure angle are large, the crank connecting rod mechanism is a stroke amplifying mechanism, and the hydraulic pump can output low-pressure and high-flow liquid, and when the transmission angle and the pressure angle are small, the crank connecting rod mechanism is a force amplifying mechanism, and the hydraulic pump can output high-pressure and small-flow liquid.

Railway vehicle gear device of parallel cardan drive system

Abstract: A low-cost railway vehicle gear device of parallel cardan drive system is provided in which the vibrations and noises can be reduced only by means of 2-D tooth surface modifications. In a railway vehicle gear device of parallel cardan drive system having a helical pinion ( 1 ) and a helical gear wheel ( 2 ), a pinion and a gear wheel respectively having gear specifications of module of 4 to 8, pressure angle of 20 to 30°, and helix angle of 15 to 30°, crowning is performed on a gear surface in the flank line direction of the pinion. The tooth surface ( 11 ) has a shape of a sinusoidal curve with an apex ( 11 a ) being positioned in a central area of the face width direction of the pinion, the sinusoidal curve being expressed by a single sinusoidal function and extending over an entire width in the face width direction of the helical pinion.

Study of the influence of the design parameters on the efficiency of spur gears

Abstract: The friction power losses in spur gears can be computed as the integral, along the entire path of contact, of the normal load, multiplied by the friction coefficient and the elemental sliding. Good agreement with experimental results are obtained by estimating the load from the minimum potential energy load sharing model, and the friction coefficient from the equation provided by Xu in 2005. From this approach, a complete study of the influence of the design parameters (number of teeth, gear ratio, pressure angle, addendum modification coefficients, etc.) on the mechanical efficiency is presented.

Transmission Theory and Typical Structure of Nonuniform Mechanism with Movable Teeth

Abstract: Thanks to characteristics of compact structure, high load strength and good manufacture technics, the movable teeth transmission is expanded to the nonuniform transmission filed. The basic structure of nonconstant mechanism with movable rods is introduced. The profile formula of inner ring is constructed by simple cosine function and the outer is built under given transmission ratio. The continuous rotation condition, the transmission efficiency and the pressure angle among the rods, inner and outer rings of movable teeth device are discussed, which could provide theory base for its design. In addition, according to the initial position of movable rods, the mechanism is divided to two basic types. Ten different results are developed by fixing the rods, inner ring and outer ring separately. A movable teeth device with kinematic feature of elliptical gears is designed. An analysis of ten motion types of the mechanism is made under a set of same geometric datum. The simulation states that the nonuniform mechanism with movable teeth has bright application prospects by means of simple manufacturing process and transmission diversity.

Simulation and Analysis about Different Pressure Angle in Involute Gears Based on Neural Network

Abstract: This article introduced neural network, discusses the neural networks model and its learning process. Using the MATLAB environment research and analysis the involute gear undercutting relationship, which under different pressure angles. In the number of teeth or modulus has been scheduled environment apply the nonlinear mapping characteristics of neural networks to involute gear undercutting do a more accurate simulation. This provides a theoretical basis for different pressure angle involute gear in gear transmission design.

Gear machining apparatus

Abstract: Provided are a gear machining apparatus and a gear machining method with which the surface roughness, in a tooth profile evaluation range, of the surfaces of the teeth of a gear can be improved. This gear machining apparatus (1) machines shapes a gear (4) by machining a workpiece (4) with a grinding wheel, and comprises: a threaded grinding wheel (32) that shapes a gear (4) by machining a workpiece (4); and a disc-shaped dresser (36) that shapes the threaded grinding wheel (32) while rotating with the threaded grinding wheel (32) in a meshed state. A pressure angle (a) of the dresser (36) is designed to be dislocated such that a reference pitch circle diameter (PCD) of the gear (4) shaped by the threaded grinding wheel (32) is outside the tooth profile evaluation range of a tooth surface (5).

Wave gear device, driving apparatus, and robot equipment

Abstract: PROBLEM TO BE SOLVED: To provide a wave gear device improved in torsional rigidity, and robot equipment including the wave gear device.SOLUTION: A wave gear device 150 includes a rigid inner gear 20, a flexible outer gear 30, and a wave generator 40. The flexible outer gear 30 has a cylindrical shank part 31 having outer teeth 33 formed therein and a fitting part 32 which is connected to a base end 31a of the shank part 31. The rigid inner gear 20 is arranged outside the shank part 31 so that inner teeth 22 mesh with the outer teeth 33. The wave generator 40 mesh the outer teeth 33 partially with the inner teeth 22 while bending the shank part 31 elliptically and rotates on the rotary shaft to move the meshing position in a peripheral direction. The inner teeth 22 of the rigid inner gear 20 are formed so as to have a smaller pitch circle at a second end 22b than at a first end 22 and also so as to have a larger pressure angle at the second end 22b than at the first end 22a.

Drafting of involute spur-gears in AutoCAD-VBA customized

Abstract: The design of efficient and reliable gearing mechanism is governed, among other factors, by its ability to withstand the frictional contact condition and high bending stresses experienced at the tooth root. One of the major impediments facing designers is the effective drafting of gears to required configuration. For involutes spur gears, the geometry is tedious and time-consuming; and the geometric complexity increases with helical, bevel and worm gears. This study presents a model developed by utilizing the integration of VBA technology built in AutoCAD for the drafting of spur gear to standard configuration. The design was based on full-depth involute gears of pressure angles 14½°, 20°, and 25°; with module ranging between 0.3 and 25 mm, and number of teeth varying between 12 and 60. The algorithm employed the conventional manual drafting techniques by navigating the IDE of VBA with AutoCAD objects, properties, methods, events, and application of errors handling techniques that will ensure smooth running of the model. The model was tested by physically comparing gear tooth template of the automated and manual techniques for three cases of 14-tooth spur gears with pressure angles 20° and modules 6, 8, and 10; and gave a good representation of the tested cases. The model was implemented for simulation of cases of varying modules and varying number of teeth to investigate the significance of module and pressure angle on the gear structure and tooth profile. The model’s flexibility for simulation makes it a virtual prototyping tool that can enhance design, analysis and also makes it a veritable educational tool.

Frame-shaped hood on 3D camera

Abstract: The utility model discloses a frame-shaped hood on a 3D camera. The frame-shaped hood comprises a rectangular hood whose front part is open. Lens holes are arranged on a back plate and a bottom plate of the hood. A simple reflection mirror frame which forms an angle of 45 degrees with two lens holes are arranged in the hood. Semitransparent and semireflexive glass is arranged on the simple reflection mirror frame. A data display is arranged on the hood. The data display is used for displaying the optical axis and the pressure angle between two lenses. The adjustment mode of complete subjective judgment of an operator through the effect of a 3D stereo image in the traditional technology is abandoned, which makes the adjustment of the optical axis and the pressure angle accurate. When the optical axis and the pressure angle need to be adjusted to previous specific positions, adjusting the data on the data display to corresponding parameters is needed. Repeated adjustment of the operator through the subjective judgment is no longer needed, thus adjustment efficiency and accuracy are improved.