A New Steering mechanism Using Noncircular Gears.

A non-circular planetary gears train beating-up mechanism was proposed, the ideal kinematic curve of beating-up rockshaft was constructed and the reverse model of the pitch curve of non-circular gears was established based on the ideal kinematic curve. When the first-level non-circular gears were set as elliptical gears, the maximum swinging angle of the sley and the influence of the elliptical gears' eccentricity on the concavo-convex characteristic of the second-level non-circular gears were analyzed. Provided with a set of parameters, the pitch curves and tooth profiles of the second-level non-circular gears were determined by reverse method. The result has shown that non-circular planetary gears train beating-up mechanism can meet the requirements of beating-up process.

This paper deals with experiments of the new steering mechanism which has been proposed in the first report. First of all, the elliptical gears for the steering mechanism were cut with the NC gear shaper developed by the authors, and the error of the rotational angles of the elliptical gears was measured. Then, the authors manufactured a wheeled robot for trial in order to confirm the usefulness of this steering mechanism and succeeded in controlling the wheeled robot using a TV camera for eyes. Moreover, they carried out fundamental experiments. These experiments proved that the new steering mechanism had high turning ability, and can turn the wheeled robot with the small radius.

The non-circular internal gears and non-circular external gears of concave pitch curve can not be processed by gear hobbing currently. Gear shaping, compared with gear hobbing, is a more general method which can solve all the problems above. Unlike previous geometric algorithms, by using the normal vector of gear pitch curve and in combination with the processing feed of shape cutter in this paper, a three-axis linkage mathematical model of non-circular gear shaping based on the model of the envelope is obtained. At the same time, through MATLAB and Visual C++ mixed programming, a non-circular gear shaping system is developed according to the linkage model. Finally, with a pair of three order elliptic gears, and via the computer-aided manufacturing, the whole non-circular gear shaping processing in three-axis linkage CNC gear shaping machine is shown in this paper, and then proving the correctness of the linkage shaping model and the shaping method of non-circular gear.

Continuously variable transmission (CVT) of noncircular gear has the technical advantages of large bearing capacity and high transmission efficiency. The key technology of CVT with noncircular gear has been broken through some countries, and is in the stage of deep application research. Although the characteristics and design methods of noncircular gear pairs have been continuously studied in China, the noncircular gear CVT is still in the preliminary exploration and research stage. The linear functional noncircular gear pair, whose transmission ratio is a linear function in the working section, to realize continuously variable transmission was the research object in this paper. According to the required transmission ratio in the working section, the transmission ratio function in the non-working section was constructed by using a polynomial. And then the influence of pitch curve parameters in the working section on which in the non-working section was also analyzed to obtain the pitch curve suitable for transmission of this gear pair. In addition, for improving the stability and bearing capacity of gear transmission, the noncircular gear pair transmission with high contact ratio was designed. Furthermore, the accurate value of the contact tooth length was calculated based on the gear principle and the characteristics of the involute tooth profile, from this the contact tooth length error was calculated by comparing the accurate value with its actual value obtained by the rolling experiment. Finally, an indirect method to verify the contact ratio by detecting the contact length error of the tooth profile was proposed.

Little research has been done so far on the development of a simplified design technique for noncircular gears. Such a technique should take into consideration various kinematic constraints that exist in the noncircular gear pitch curve design process, to obtain appropriate gearing on the basis of a given angular velocity ratio curve. It seems that no generalized design technique has yet been established. This study used design specifications such as an angular velocity ratio curve (types of curves in individual segments and their coefficients) and center distance to design a pair of noncircular gears. The center distance was kept constant. The design process for the pitch curve was obtained and extracted from various kinematic constraints. Based on thses results, We developed a design automation technique for the pitch curve for noncircular gears, with given arbitrary angular velocity ratio curve.

Gear Geometry and Applied Theory, second ed., F.L. Litvin, A. Fuentes. Cambridge University Press, Cambridge (2004)

The components of an electromagnetic shell system should be able to sustain the impact of high-strength instantaneous acceleration when the system is launched. The dynamic characteristics of high overload present significant challenges in the component (electronic and mechanical) design and part assembly of a steering gear system. This paper proposes a new design strategy for the servo system of a high-overload electromagnetic projectile. First, according to the special environment index parameters of a high-overload electromagnetic shell steering system, a new anti-overload deceleration mechanism that combines a triangular thread lead screw, a shift fork, and the entire anti-high-overload mechanical structure is proposed. The transient dynamic vibration characteristics of the entire high overload are analyzed. Based on the integrated module method for complex mechanical and electrical equipment, a mathematical model of the full closed-loop electromagnetic shell actuator system is established, and its dynamic characteristics are analyzed. Finally, a prototype of the high-overload electromagnetic projectile steering system is manufactured. By testing the maximum rudder deflection angle and the frequency and step responses of the system, the dynamic characteristics of the new high-overload electromagnetic shell actuator system are verified. This study provides a new method for designing high-overload electromagnetic shell steering gears.

The paper presents the dynamic analysis of a steering mechanism for a road vehicle, considering the deformability of some elements, such as the steering tie rods. Both the steering and suspension mechanisms were analysed form structural point of view. The kinematic scheme of the assembly was done, followed by a study of their parts and kinematic joints. Then, there was calculated the degree of mobility of the mechanism. The dynamic analysis was approached in case of a stationary vehicle. Considering the geometry of the real model, it was designed the 3D model of the mechanisms assembly. Respecting the positioning on the vehicle, the model was exported to the Adams View software, where the components were assembled, defining the kinematics joints. The values obtained by simulations are compared to those obtained by experimental means. Also, results can be used to optimize aspects of the mechanical system. Finite element analysis was performed to study the contact stress distribution of the rack and pinion gear, considering wheels-road contact and also the friction from the spherical and cylindrical joints of the mechanism. The rack and pinion gear was defined by coupling the rotational motion of the pinion with the translation of the rack.

Insufficiency of traditional EB-type silk reeling machine was pointed out after analyzing its traverse mechanism. A novel traverse mechanism driven by non-circular gears with Fourier pitch-line was proposed in order to make up the insufficiency of the traditional EB-type machine. Kinematical mathematic model of this mechanism was established and an aided analysis and simulation software was compiled. A group of preferable parameters was obtained by means of human-computer interactive optimization method. New advantages of uniform roundtrip velocity and better silk winding shape were achieved by the novel traverse mechanism compared to the traditional EB-type mechanism.

The design flexibility and transmission stability of the non-circular gears can be improved using the helical tooth scheme. Herein, a linkage model was derived for hobbing the helical non-circular gears based on the influence of the axial feed motion of the hob on the motion of the projecting rack on the gear-blank end face. This axial feed motion produces additional motion effects on the rotary axis of the gear-blank and the moving axis of the hob. Further, the accuracy of the linkage model was verified by kinematic simulations. The global convergence characteristics of the transcendental equation used for obtaining the polar angle of the pitch curve were ascertained to derive the interpolation calculation process for the linkage model-based electronic gearbox. The cause of cumulative error during the multi-turn hobbing process of the gear blank was analyzed. The error accumulation was effectively controlled by optimizing the interpolation algorithm. The hobbing experiments and meshing transmission test were conducted using the self-developed non-circular gear hobbing system to verify the effectiveness of the linkage model and interpolation algorithm.

In N-G-W type non-circular planetary gear strain, the planetary gear is meshed both with the center wheel and the inner gear ring. The parameters which the design of the planetary wheel system required can be received according to the three-order elliptic equation which consist of continuous smooth closed curves as the pitch curve equation of the center wheel, and on the basis of planetary gear teeths relation, the closed condition of the pitch curve and the teeth uniformly distributed in the curve. This paper studied the design process of the pitch curve on an N-G-W type internal-curve planet gear pump by a practical example.

<div class="htmlview paragraph">This paper covers the subject of commercial vehicle manual and power steering system design and development from the total vehicle viewpoint. It includes a discussion on the interrelationship of cab package, front suspension, and tires on truck steering as well as a description of the pertinent steering system characteristics. The function of the various steering system components are described as reference for system design and selection of industry available hardware for a specific application. The topics are presented in a manner which explains the logic of total steering system design from the initial stage of vehicle concept through the initial package proposal.</div>

Noncircular Gears: Design and Generation represents the extension of the modern theory of gearing applied to the design and manufacture of the main types of noncircular gears: conventional and modified elliptical gears, eccentric gears, oval gears, gears with lobes, and twisted gears. This book is enhanced by updated theoretical description of the methods of generation of noncircular gears by enveloping methods similar to those applied to the generation of circular gears. Noncircular Gears: Design and Generation also offers new developments directed to extend the application of noncircular gears for output speed variation and generation of functions. Numerous numerical examples show the application of the developed theory. This book aims to extend the application of noncircular gear drives in mechanisms and industry.

The model of all terrain vehicle and steering system is built up by use of SolidWorks which is 3D mechanical design software. The parameters of all terrain vehicle are necessary. The real movement state of steering system is simulated through virtual simulating tool ADAMS. The movement state and performance are tested. The results verify the design of vehicle is logical and steering system is smooth. The parameters of simulating model provide the reference for designing sample.

In recent years, a ratio of owner passenger cars in all car-registrations in Japan exceeds more than 70%. Therefore, the owner-cars are as very important means of transportation system. On the other hand, the boarding rate per a vehicle decreases gradually, and, recently, it has become about 1.3 persons per one vehicle. From these situations, a development of the personal mobility vehicle as one of the transportation tools is effective. From the reasons, various kinds of personal mobility vehicles are proposed in recent years. From a viewpoint of road share reduction and of energy consumption, we propose a personal mobility vehicle with rolling-motion such as two-wheeled vehicles. Since the steering system is connected by linkages between steering system and rolling suspension system, driver controls not only steering angle but also rolling angle at the same time using steer angle. As the result, it is shown that the link ratio realizes very large characteristic region by changing according to speed.