Acoustical behavior of loss-optimized involute gears

2021 ◽  
Vol 263 (5) ◽  
pp. 1574-1585
Author(s):  
Sebastian Sepp ◽  
Joshua Goetz ◽  
Karsten Stahl
Keyword(s):  
High Speed ◽  
Low Noise ◽  
Test Results ◽  
Motor Speed ◽  
Power Train ◽  
Higher Power ◽  
Involute Gears ◽  
Gear Geometry ◽  
Drive Systems ◽  
Design Calculations

The progressing electrification of vehicle drive systems focuses more and more on efficient high-speed concepts. Increasing the motor speed leads to a higher power density of the electrified power train and thereby to an increased range for battery electric vehicles. The high rotational speeds cause new challenges in designing gearboxes regarding the efficiency and the acoustical behavior. Most present gearings in conventional vehicles are designed with high tooth depths to ensure low noise excitation behavior combined with the best possible efficiency. By changing the gear geometry to smaller tooth depths with higher pressure angles, it is possible to further decrease gear losses. However, the loss-optimized gear geometry must not jeopardize the beneficial acoustical behavior. In theoretical studies, the acoustical behavior of loss-optimized gears are investigated and compared to gearings designed according to the state of the art. Design calculations of the excitations of all ideal gears without deviations are on similar levels. However, application of such gear geometries faces severe challenges because the sensitivity to manufacturing deviations may be high. In this paper, simulation results and test results between low-NVH gears and loss-optimized gears are documented and analyzed.

HSCT Forward Swept Fan Performance

2003 ◽  
Author(s):  
Robert J. Neubert ◽  
Charles P. Gendrich
Keyword(s):  
High Speed ◽  
State Of The Art ◽  
Low Noise ◽  
Navier Stokes ◽  
Light Weight ◽  
Test Results ◽  
Flow Solver ◽  
Stall Margin ◽  
Fan Performance ◽  
Multi Stage

Previous experimental and analytical studies have demonstrated the potential for significant improvements in efficiency and stall margin with forward swept rotor blading. This paper extends the assessment to a light weight, low noise two stage fan designed and fabricated under the NASA High Speed Civil Transport program. The experimental investigation evaluates the effect of forward sweep on efficiency and stall margin relative to the predicted levels for a radial fan designed for the same requirements. Efficiency was above multi-stage fan state of the art and stall margin was significantly greater than predicted based on radial fan experience. In addition, the effects of increasing the axial gap between the IGV and rotor 1, as well as R1 to S1 axial gap are evaluated. The increased axial gap between R1 & S1 had a much greater effect on performance than increasing the IGV to R1 gap. And, 3D Navier-Stokes flow solver analysis was performed for comparison to test results.

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

Measurement and Analysis on Transient Thermal Characteristics of High Speed Motorized Spindle

2011 ◽  
Vol 52-54 ◽  
pp. 2021-2026
Author(s):  
Gui Ling Deng ◽  
Can Zhou
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Thermal Characteristics ◽  
Measuring System ◽  
Test Results ◽  
Motorized Spindle ◽  
Measurement And Analysis ◽  
Turning Center ◽  
Transient Thermal ◽  
Deformation Compensation

Thermal deformation is an important factor to affect the accuracy of the motorized spindle, the core component of high-speed machine tool. To understand the spindle system transient thermal characteristics of the high-speed turning center CH7516GS, some high-precision sensors and high-frequency data acquisition system is used to establish the temperature and displacement measuring system. The thermal deformation compensation model is established on the basis of the experimental test results.

A 25 Gbps VCSEL driving ASIC: an attempt for ultra-high-speed front-end readout applications

2022 ◽  
Vol 17 (01) ◽  
pp. C01040
Author(s):  
C. Zhao ◽  
D. Guo ◽  
Q. Chen ◽  
N. Fang ◽  
Y. Gan ◽  
...  
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Test Results ◽  
Eye Diagram ◽  
Optical Links ◽  
Optical Module ◽  
Active Feedback ◽  
High Bandwidth ◽  
Output Driver ◽  
Very High

Abstract This paper presents the design and the test results of a 25 Gbps VCSEL driving ASIC fabricated in a 55 nm CMOS technology as an attempt for the future very high-speed optical links. The VCSEL driving ASIC is composed of an input equalizer stage, a pre-driver stage and a novel output driver stage. To achieve high bandwidth, the pre-driver stage combines the inductor-shared peaking structure and the active-feedback technique. A novel output driver stage uses the pseudo differential CML driver structure and the adjustable FFE pre-emphasis technique to improve the bandwidth. This VCSEL driver has been integrated in a customized optical module with a VCSEL array. Both the electrical function and optical performance have been fully evaluated. The output optical eye diagram has passed the eye mask test at the data rate of 25 Gbps. The peak-to-peak jitter of 25 Gbps optical eye is 19.5 ps and the RMS jitter is 2.9 ps.

A parameterized numerical method for generating discrete helical gear tooth surface allowing non-standard geometry

2008 ◽  
Vol 222 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Gear Tooth ◽  
Numerical Approach ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tool Profile ◽  
Standard Geometry ◽  
Gear Manufacturing ◽  
Involute Gears ◽  
Gear Geometry ◽  
Tooth Flank

Gear analysis is typically performed using calculation based on gear standards. Standards provide a good basis in gear geometry calculation for involute gears, but these are unsatisfactory for handling geometry deviations such as tooth flank modifications. The efficient utilization of finite-element calculation also requires the geometry generation to be parameterized. A parameterized numerical approach was developed to create discrete helical gear geometry and contact line by simulating the gear manufacturing, i.e. the hobbing process. This method is based on coordinate transformations and a wide set of numerical calculation points and their synchronization, which permits deviations from common involute geometry. As an example, the model is applied to protuberance tool profile and grinding with tip relief. A fairly low number of calculation points are needed to create tooth flank profiles where error is <1 μm.

scholarly journals Development of intelligent preamplifier for semiconductor detectors

2021 ◽  
pp. 8-8
Author(s):  
Vladimir Kondratjev ◽  
Vasily Litvinsky ◽  
Serhii Pohuliai ◽  
Stanislavs Lozkins
Keyword(s):  
Liquid Nitrogen ◽  
High Speed ◽  
Temperature Sensors ◽  
Low Noise ◽  
Nitrogen Level ◽  
Semiconductor Detectors ◽  
Resistive Feedback ◽  
Charge Sensitive Preamplifier ◽  
Gamma Detectors

The results of engineering an intelligent preamplifier for HPGe gamma-detectors are presented. An intelligent preamplifier is a low-noise, high-speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows to manage performance of the internal testing pulser, sensor of liquid nitrogen level in Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, setup and parameter measurements are controlled by a software.

scholarly journals RANCANGBANGUN RANGKAIAN INVERTER SPWM UNIPOLAR 1 FASA DENGAN PENGATURAN FREKUENSI OUTPUT

2021 ◽  
Vol 9 (1) ◽  
pp. 46-49
Author(s):  
Fathoni ◽  
Agus Pracoyo ◽  
Totok Winarno ◽  
Rizal Sabillah
Keyword(s):  
Output Voltage ◽  
Test Results ◽  
Motor Speed ◽  
Output Frequency ◽  
Ac Motor ◽  
Power Part ◽  
The Difference ◽  
The Right ◽  
Frequency Variations

Changing the dc sgnal to ac signal is done for te purpose of load regulations, such as the ac motor speed, heater and lamp. Inverter work is done by ac rectification first and then converted again to a 1 phase ac signal. The ac output signal is a sinosoidal PWM (SPWM) type of unipolar 220 volts from the input 24 volt dc voltage. Unipolar SPWM signal generation is done by a microcontroller with programming. The number of counts (resolutions) of the SPWM signal and the period are set from the amount in the register, can be set to 8 bits or other constants. The power part of the SPWM inverter is the N channel MOSFET bridge circuit H with IR2110 solid state driver. Step transformer as a load while step-up the inverter output voltage. Determination of the output frequency is set through a rotary encoder that can be adjusted up (increment) or down (decrement). There are 5 frequency variations, namely 30, 40, 50, 60 and 70 Hz. To get the inverter efficiency, the type of MOSFET used is chosen to have the type that has a low RDS (on) value and the right driving pulse, according to the switch configuration. Measurement of the output frequency is done by reading the image on the osciloscope. The observations show a frequency value that is almost the same as the constant. The test results show the difference in output voltage which is reduced at a 30 watt load.

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