Browse Topic: Gears
ABSTRACT Curtiss-Wright has developed an acoustic based sensor technology for measuring friction, shock, and dynamic load transfer between moving parts in machinery. This technology provides a means of detecting and analyzing machine structure borne ultrasonic frequency sounds caused by friction and shock events between the moving parts of the machine. Electrical signals from the sensors are amplified and filtered to remove unwanted low frequency vibration energy. The resulting data is analyzed as a computed stress wave energy value that considers the amplitude, shape, duration and rates of all friction and shock events that occur during a reference time interval. The ability to separate stress waves from the lower frequency operational noise makes this technology capable of detecting damaged gears/bearings and changes in lubrication in equipment earlier than other techniques, and before failure progression increases cost of repair. Already TRL9 in adjacent industries, this technology
ABSTRACT The HMPT500-3 is a split torque path hydrostatic / mechanical continuously variable transmission used in the Bradley Fighting Vehicle. Power transmission and steering is accomplished through the interaction of six planetary gear sets and two variable displacement hydrostatic pump / motor units (HSUs). Power flow in the HMPT500-3 is extremely complex, with numerous feedback paths within the planetary gear train. Without a clearly defined power flow path from gear set to gear set, the analysis cannot be handled in the conventional stepwise manner. The complete speed and torque equation sets must be solved simultaneously for all components. A linear algebraic approach was developed to model forward operation of the HMPT500-3 without steering. The left and right HSUs are lumped in a single unit, and the steering differential is ignored. A reduced set of 14 simultaneous equations for speed and 14 simultaneous equations for torque enable modeling of the ideal (lossless) power flow
With the advancement of regulatory norms in automobile industry, there is a challenge to meet performance efficiency targets, especially with a lightweight platform, while providing superior driving experience to customers. The shift towards weight optimization, makes the vehicle structure more susceptible to transfer a diverse range of noise and vibrations through body. Although most undesirable noises perceived inside the cabin can be reduced by superior technology engine mounts and NVH packaging, all such solutions lead to cost addition. Intelligent considerations in part design can be used to supplement predictable transfer paths to quell the unwanted vibrations. One such case is of the gear whine noise in certain rpm bands caused by inherent gear meshing frequency coinciding with natural frequency of an engine mounting bracket. This paper demonstrates two methodologies to counter such a phenomenon, either through engine mount bracket natural frequency optimization or addition of a
Vehicle transmission gear rattle is one of the most critical NVH irritants for refined vehicles. It is perceived more dominantly in lower gears of vehicle running. It depends on various design parameters like engine input torque amplitude & fluctuations, driveline torsional vibrations, gear micro & macro geometry, shaft flexibility, etc. Establishing exact contribution of each of these parameters to transmission rattle, thru experimental or simulation technique, is very challenging. Current paper explains the NVH CAE benchmark approach deployed to understand difference in rattle behavior of two transmission designs. Paper focuses on simulation of gear impact power and its sensitivity to transmission shaft deflections. Impact power is one of the indicators of transmission rattle noise and transmission shaft deflection is one of the contributors for gear impact power. 3D MBD simulations are carried out to calculate loose gear impact power by applying angular acceleration input to
As a car OEM, we continuously strive to set the bar for competitors with every product. Consumer travel experiences are enhanced by increasing passenger cabin silence. There is only one steering system opening in the firewall panel, which is used for allowing intermediate shaft's fitment on the pinion shaft of the steering gear. The steering grommet is the sole component that covers the firewall cut-out without disrupting steering operations, which has a substantial impact on the NVH performance of the vehicle. It is typically used in cars to eliminate engine noise and dust entering to passenger compartment. The part is assembled inside the vehicle where the steering intermediate shaft passing through BIW firewall panel. We use a bearing, plastic bush, or direct rubber interference design in the steering grommet to accommodate the rotational input the driver provides to turn the automobile. However, occasionally noise may be produced due to uneven bearing or plastic bush loading or a
Worldwide automotive sector regulatory norms have changed and become more stringent and complex to control environmental noise and air pollution. To continue this trend, the Indian Ministry of Road Transport is going to impose new vehicle exterior pass-by noise regulatory norms IS 3028:2023 (Part2) to control urban area noise pollution. This paper studies the synthesis of M1 category vehicle driving acceleration, dominant noise source, and frequency contribution in exterior PBN level. A vehicle acceleration analysis study was carried out to achieve an optimized pass by noise (PBN) level based on the vehicle’s PMR ratio, reference, and measured test acceleration data. Based on the analysis, test gear strategy was decided to achieve a lower PBN level. This strategy involved increasing the effective final drive ratio and optimizing engine calibration, resulting in improvement with acceleration in the ith gear. This increased acceleration surpassed the upper limit of the reference
NASA intended its Reusable Launch Vehicle program of the 1990s to demonstrate technologies that would enable hypersonic spaceplanes to make affordable, repeated trips into space. It was never intended to improve the performance of hunting, skiing, and sports gear, but, more than 20 years after its cancellation, that’s what’s happened
Integrating sensors into rotational mechanisms could make it possible for engineers to build smart hinges that know when a door has been opened, or gears inside a motor that tell a mechanic how fast they are rotating. MIT engineers have now developed a way to easily integrate sensors into these types of mechanisms, with 3D printing
Figures 1 through 6 illustrate in simplified form some of the more common planetary gears, gearsets, and geartrain arrangements in order to establish applicable terminology. Figures 7 and 8 provide additional examples that use elements of those gear arrangements
Non-terrestrial networks (NTN) promise to finally eliminate coverage gaps across the globe. Beyond commercial applications, these fifth generation (5G) cellular networks create new use cases for critical communications and military operations. For such applications to effectively serve these mission-critical areas, however, their performance must be assured. With RF system measurement science, 5G NTN equipment developers, integrators, and network operators can reduce the time needed to create and deploy networks, using virtual engineering for first-pass success when committing to physical gear. Simulation and emulation support NTN exploration and testing, verifying current performance while supporting next-generation evolutions
The gear is one of the oldest mechanical tools and led to machines ranging from early irrigation systems and clocks, to modern engines and robotics. Researchers have utilized a catalytic reaction that causes a two-dimensional, chemically coated sheet to spontaneously “morph” into a three-dimensional gear that performs sustained work
Side door latches in an automotive play a major role in occupants’ safety. The latches consist of both retention assembly and actuator assembly. The actuator assembly majorly consists of motor, gear & other components and these are protected through a Plastic Lower case and Housing. The Lower case (over-mold) with the Electrical Component Carrier - ECC (pre-mold) plays an important role in providing electrical power supply to the latch system. Since these parts are manufactured with terminal traces & plastics, upfront mold flow simulations help the product teams to evaluate the short fills, warpage, and other quality aspects in the critical areas of these components. In the part assembly station, the ECC (pre-mold) and the Lower case (over-mold) are connected to the Motor on one side and the Connector on the other. The proper alignment of the pre-mold pins is of great importance and the pre-mold must not be externally visible once the molding is complete. During the prototype build
This SAE Aerospace Recommended Practice (ARP) provides a guide for preparation of requirements for general design, performance, and testing of mechanical geared rotary actuators intended to be used for applications requiring motion control in response to manual or automatic power control system inputs
Within gear pair development, the simulation of loaded transmission error, line of action and summarized mesh point are crucial information in design optimization as well as reliability, NVH and efficiency prediction. These properties and variables are difficult to evaluate and are usually only assessed through proxy-variables such as unloaded transmission error or contact pattern assessment. Alternatively, large design loops can be generated when prototypes are produced to directly assess the results of reliability, NVH and efficiency and simulation models updated to the results, but not directly calibrated. This work will showcase an advanced test facility with the unique capabilities to evaluate all gear contact types (including hypoid, beveloid, cylindrical and spiral) under loaded conditions while assessing position and force data that can be used to validate simulation models directly and enhance design development. Results will be shown for the assessment of hypoid gear fatigue
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