Planetary Gear Transmission Research Articles

Rare-earth permanent magnet machine system of electric vehicle

In order to reach the driving request of electric vehicle(EV),the EV power-driven system is researched,which takes rare-earth permanent magnet machine as key technology. A bran-new automatic control mode of traction motor is researched and applied in the EVs.At the same time a kind of planetary gear transmission case is designed,which has simple structure and excellent characteristics.Otherwise it is controlled by wire.And the influences on EV longitudinal amenity are analyzed,which are from the moment characteristics of the motor driving system.By the strategy of automatic weak- magnetism control,the motor system can fit all the need for driven system of EV.Matching the motor with double shii~s, guarantee the drive system work efficiency on a high level when the EV is in the max speed.

ELASTODYNAMIC ANALYSIS OF MULTI-RING GEAR REDUCERS IN CONSIDERATION OF DEFORMATIONS OF GEAR-COUPLERS

The multi-ring gear reducer (MRGR) is a novel class of planetary gear transmission devices with small tooth number difference. It has numerous advantages over common gear reducers such as large transmission ratio, high loading capacity, compact volume, low fabricating cost and wide adaptability. To improve dynamic performance of the MRGR,the systematic elastodynamic equation is formulated by taking into account the elasticity of high-speed shafts, gear-couplers, meshing teeth and bearings. An ANSYS based finite element model is developed for the gear-couplers whose rigid-body motions are constrained by linear springs with equivalent stiffness. The stresses, displacements and elastic deformations of the gear-couplers are investigated in a whole motion cycle of the parallelogram mechanism. The actual loading states of the components are obtained by integrating iteratively the ANSYS based finite element analysis of the gear-couplers and the elastodynamic analysis of the MRGR. The simulation results reveal that both longitudinal and lateral deformations of the gear-couplers will greatly affect dynamic performance of the MRGR and the rating life of planetary bearings will be shortened as a result of elastic deformations of the gear-couplers.

KHV Indexing Cam Mechanism: A New Intermittent Mechanism

The KHV indexing cam mechanism is a new type intermittent mechanism that has a structure similar to the KHV planetary gear transmission (one type of the planetary drive with small teeth difference, where K indicates the sun gear, H indicates the pivoted arm, and V indicates the output mechanism). This paper focuses on the generation of a pitch curve and a cam profile in such a new mechanism. Three types of the KHV indexing cam mechanism are compared and discussed, and the equations of cam's pitch curves are derived. The cam's profile is generated by Boolean operations on the offsets of the cam's pitch curve. After this, the cusps on the cam profile are eliminated and replaced by a particular Hermite curve. The animations of all three types are illustrated, and a prototype of such mechanism is reported.

Dynamic load analysis of bearings in a three-ring planetary gear transmission

Dynamic load analysis of bearings in a three-ring planetary gear transmission

114 一般型車椅子用遊星歯車変速機と逆転防止機構の設計

114 一般型車椅子用遊星歯車変速機と逆転防止機構の設計

Balancing Commonality and Performance within the Concurrent Design of Multiple Products in a Product Family

Product family design involves the concurrent design of multiple products based on a common product platform to satisfy a variety of markets. The success of the resulting product family relies heavily on properly balancing the commonality of the product platform with the individual product performance within the product family. To help resolve this tradeoff, we present the Product Variety Tradeoff Evaluation Method for assessing alternative product platform concepts with varying levels of commonality. Two examples are presented to demonstrate the proposed method at both the detailed and the early stages of design. The redesign of a planetary gear transmission for a family of four cordless drills demonstrates the use of the method in the detailed stages of design, while the design of a family of three General Aviation Aircraft demonstrates the use of the method in the preliminary stages of design. The emphasis in this paper is on the effectiveness of the proposed method in evaluating this tradeoff and not on the results of the examples, per se.

Effects of Planetary Speed-Reduction Ratio on Mean Service Life

Planetary-gear transmissions are compact speed reductions which use parallel-load paths to transmit high power. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single-plane planetary transmission, the speed-reduction ratio must be greater than two for planet gears to exist. As the ratio increases, so does the size of the planets relative to the sizes of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a spur-gear planetary with a fixed size, speed-reduction ratio, input speed, power and materials. The planetary-gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the ball bearings and spur gears in the reduction. Planet-bearing life strongly influences the optimal reduction lives which point to an optimal planetary reduction ratio in the neighborhood of four to five.

Matrix System for the Analysis of Planetary Transmissions

This paper presents a new general analysis method for planetary gear transmission systems. Instead of studying portions of a transmission, one can analyze a whole planetary transmission system with a general program. Not only the kinematics, but also dynamics of a transmission are studied. The whole process of analysis is standardized to become very straight forward, making it especially suitable for the computer-aided analysis of the vehicle planetary transmissions.

Development and validation of a model for predicting the performance of a downhole pneumatic turbine-powered drilling engine

The pneumatic turbine-powered drilling engine (PTDE) is a unique tool for directional drilling when using air or gas as the drilling fluid. The engine consists of a pneumatic turbine motor coupled to the bit by a four-stage planetary gear transmission and a thrust-bearing assembly, and is supported within a steel housing. The tool was built and bench tested in New Mexico, and field tested at the Geysers Geothermal Field in Santa Rosa (Calif.). In order to predict and analyze the field performance of the tool, two analytical models were derived and validated. A torque model was developed to predict the bit torque as a function of bit rpm at a given air-flow rate and a known air speed entering the turbine rotor. A pressure-loss model was used to calculate the air speed entering the rotor as a function of the bottomhole air pressure, the bottomhole temperature, the air-flow rate, the size of the bit jets, and the tool internal geometry. The two models were validated in a full-scale bench test of the two prototype tools. The validated models were then used to develop turbine air speed and WOB response charts. These charts are for field use in selecting the engine set-up. They are used to select bit jets, and to predict required weight on bit, bit rotary speed, bit torque and bit horsepower.

Planetary-gear electric drive for the control of shut-off pipeline fittings

This author recommends that a planetary gear be substituted for the worm gear typically used as the power reducing gear in electric drives for control of shut-off pipeline fittings. He uses a diagram to represent the planetary gear transmission with coaxial and with noncoaxial arrangement of the elements. Another figure illustrates the construction of the planetary gear electric drive. The kind of device he describes is smaller than the currently used driving mechanism by a factor of 2 to 3. It has higher efficiency, requires less metal, is less complicated in manufacture, and simpler to use. Furthermore, he concludes, planetary gear drives make it possible to simplify the design of the fitting by replacing the bow unit with a simpler flange and to reduce operational costs since the planetary gear does not require lubrication.

SMALL WATERPLANE AREA TWIN HULL (SWA TH) COMBA TANT SHIP PARAMETRIC STUDY

ABSTRACTThis study defines the anticipated size and speed of SWATH Escort Ships. The study baseline assumes conventional state‐of‐the‐art materials, subsystems, design philosophy, and operational practices. Double reduction gear and planetary gear transmission systems were included with prime movers in the hulls. Conventional geared‐electric, right‐angle drive and cryogenic systems with turbines in the box or cross‐structure were also studied. Installed powers of 45,000 SHP (2 LM2500s), 70,000 SHP (2 FT9s), 90,000 SHP (2 LM5000s or 4 LM2500s), 140,000 SHP (4 FT9s), and 180,000 SHP (4 LM5000s) were studied. In addition, the sensitivity of the results to assumptions made in the study was examined.The study results show that current technology SWATH Escort Ship will displace 5,000 to 8,000 tons. Sustained speeds of these ships will be about 25 knots. Speeds of 30 knots or better are possible by combining a right‐angle drive or cryogenic transmission system with increased installed horsepower. Increased ship sizes accompany these increased speeds. Such changes will require strong endorsement by the Operational Community.

Extension of a method of analysis of planetary gear trains

A method of analysis of planetary gear transmission systems is extended here to include the case of idler planets. The method is general and easily applied to multi-degree of freedom systems.

Analysis of an Improved Planetary Gear-Transmission Bearing

In planetary-gear transmissions, especially for aircraft applications, the planet gears are frequently made integral with the outer rings of rolling bearings. Thus the outer ring of the rolling bearing is subjected to the tangential, radial, and moment loading attendant to spur gears. If the outer ring of the bearing is relatively thin, the distortion induced therein by the gear forces alters the distribution of load from that of a roller bearing with a rigid outer ring, causing a significant reduction in the bearing fatigue life. Since the maximum rolling-element loads in the bearing occur in close angular proximity of the points of load application, it would appear that the magnitude of these rolling-element loads may be diminished and fatigue life subsequently increased by selectively applying clearance between rolling elements and raceway at the points of load application. In fact, theoretical analysis of a planetary-gear bearing having an out-of-round inner ring, wherein the major axis is oriented parallel to the tangential gear-tooth load, indicates that a condition of optimum clearance and out-of-round exists with respect to bearing fatigue life. An increase in fatigue life of approximately 40 percent is indicated with only a nominal amount of out-of-round.

Closure to “Discussion of ‘Analysis of an Improved Planetary Gear-Transmission Bearing’” (1964, ASME J. Basic Eng., 86, pp. 461–462)

Closure to “Discussion of ‘Analysis of an Improved Planetary Gear-Transmission Bearing’” (1964, ASME J. Basic Eng., 86, pp. 461–462)

Evaluation of drawing lubricants for Tantalum and Uranium : R. I. Batista, G. S. Hanks, J. M. Taub and D. J. Murphy. Lubrication Engineering, 17 (9) (1961) 414–418; 5 figs., 2 tables, 1 ref

The pneumatic turbine-powered drilling engine (PTDE) is a unique tool for directional drilling when using air or gas as the drilling fluid. The engine consists of a pneumatic turbine motor coupled to the bit by a four-stage planetary gear transmission and a thrust-bearing assembly, and is supported within a steel housing. The tool was built and bench tested in New Mexico, and field tested at the Geysers Geothermal Field in Santa Rosa (Calif.). In order to predict and analyze the field performance of the tool, two analytical models were derived and validated. A torque model was developed to predict the bit torque as a function of bit rpm at a given air-flow rate and a known air speed entering the turbine rotor. A pressure-loss model was used to calculate the air speed entering the rotor as a function of the bottomhole air pressure, the bottomhole temperature, the air-flow rate, the size of the bit jets, and the tool internal geometry. The two models were validated in a full-scale bench test of the two prototype tools. The validated models were then used to develop turbine air speed and WOB response charts. These charts are for field use in selecting the engine set-up. They are used to select bit jets, and to predict required weight on bit, bit rotary speed, bit torque and bit horsepower.