Browse Topic: Transmission gears
Electric vehicle (EV) transmissions play a vital role in powering EVs by channeling energy from the electric motor to the wheels. Recently, the focus has shifted to multi-speed transmissions in the EV sector due to their potential to improve efficiency and performance. By utilizing various gear ratios, these transmissions enable the motor to function within its most efficient range across different speeds. Most of these transmissions need electric control unit (ECU) with software for optimal functionality and smoother gear shifting. These controllers incorporate controller area network (CAN) communication protocol to operate along with other ECUs. Thus validation of these transmissions is a challenge as they are clutch less, motor has to be controlled for speed matching and have electro mechanical systems replacing conventional systems for operation. This paper proposes a methodology to validate multispeed EV transmissions on a test bench. The validation setup consists of electric
In heavy-duty tippers, where challenging conditions demand high torque, planet carriers play a crucial role by enabling efficient load distribution and torque transmission while supporting gear ratio and speed variation in space-constrained systems such as automatic transmissions, hybrid drivetrains, and electric vehicles. This paper focuses on the comprehensive durability performance assessment of planet carrier housing (PCH) using duty cycles derived from road load data acquisition (RLDA) measurements for a heavy-duty tipper gearbox development program. The existing Design Validation Plan (DVP) for the planet carrier considers first gear utilization of 10-15% at 40% vehicle overload, in line with historical data. However, recent trends in mining applications revealed vehicle overloads of 55-65%, leading to an increase in first gear utilization (25-35%). This shift presents challenges for original equipment manufacturer (OEM) to enhance design durability while incorporating additional
Gear noise is a common challenge that all gear manufacturers must contend with. In tractors, while it is often sufficiently low in intensity to not pose a significant issue, there are instances where gear whine may occur which is noticeable. In such cases, identifying the source and effectively addressing the problem can prove to be particularly difficult. This paper addresses the root cause analysis carried out for the evaluation of factors influencing whine noise behavior of Spiral bevel gear pair (SO2) in a tractor transmission system. Numerous publications have been published on gear noise of spiral bevel gear pair, too many to list here. However, once the gearbox assembled into the transmission, such models are of limited practical value. The work explained in this paper is a typical example offers avenues in correcting the issue using more limited means.
Bogie frame is a main skeleton and structural member in railway system which is carrying all the loads such as Suspensions, Axles, wheels, car body, Motor, Gear box etc. The frame is subjected an exceptional and service stresses in Vertical, Longitudinal, Lateral and twist directions throughout the service life which should be withstand for a life span of 30 years without failure. The purpose of this project is to determine the Structural integrity of the Metro rail bogie frame in consideration with EN13749 standard. This paper is the outcome of bench testing of metro rail bogie frame with the application of multiaxial loading in static and dynamic campaign through which stress data is collected with strain gauge sensors and correlated with the FEA results at initial design phase. This helps to verify and evaluate the design and validate the quality of metro rail frame as per the requirement specified in EN13749:2021 European standard in early design stages.
This study develops a one-dimensional (1D) model to enhance transmission efficiency by evaluating power losses within a transmission system. The model simulates power flow and identifies losses at various stages such as gear mesh, bearing, churning, and windage losses. Using ISO/TR 14179, which provides a method for calculating the thermal transmittable power of gear drives with an analytical heat balance model, the 1D model ensures accurate thermal capacity evaluation under standard conditions. A key advantage of this 1D model is its efficiency in saving time compared to more complex 3D modelling, making it particularly useful during the conceptual stage of transmission system development. This allows engineers to quickly assess and optimize transmission efficiency before committing to more detailed and time-consuming 3D simulations. To validate the model, experimental tests were conducted at various motor speeds (RPM) and torque values, using high-precision sensors and dynamometers
Driver-in-the-Loop (DIL) simulators have become crucial tools across automotive, aerospace, and maritime industries in enabling the evaluation of design concepts, testing of critical scenarios and provision of effective training in virtual environments. With the diverse applications of DIL simulators highlighting their significance in vehicle dynamics assessment, Advanced Driver Assistance Systems (ADAS) and autonomous vehicle development, testing of complex control systems is crucial for vehicle safety. By examining the current landscape of DIL simulator use cases, this paper critically focuses on Virtual Validation of ADAS algorithms by testing of repeatable scenarios and effect on driver response time through virtual stimuli of acoustic and optical warnings generated during simulation. To receive appropriate feedback from the driver, industrial grade actuators were integrated with a real-time controller, a high-performance workstation and simulation software called Virtual Test
Model Based Design (MBD) uses mathematical modelling to create, test and refine systems in simulated environment, primarily applied in control system development. This paper discusses an approach to control gear shifting using shift logic on vehicle level for twin clutch transmission using prototype controller. Twin clutch transmission is a concept with two clutches, one at input end of the transmission called primary clutch and the other at output end of the transmission called secondary clutch. This concept is proposed to counter the challenges with conventional transmission which include increased gear shift time and effort in lower gears, potential rollback of vehicle in uphill condition and chance of missed shifts. The advantages of this concept include reduced gear shift effort and improved synchronizer life with potential for reducing the size of the synchro pack. This paper proposes a methodology to develop shift logic, integrate hardware with software, flashing and calibration
Puddling is a crucial process in rice cultivation, involving the preparation of the soil in a flooded field to create a soft, muddy seedbed. There are two classifications for puddling: full cage and half cage. Full cage puddling involves replacing the rear wheels of the tractor with steel paddle wheels, which are used to till the rice paddies directly without any additional implement. In the half cage puddling, the rear wheels remain on the tractor, and a smaller cage or paddle wheel is attached to the outside. Considering the field size, the operator often releases the clutch very quickly after a speed or direction change. This generates torque spikes, which are harmful to Transmission Gears and Clutches. This can lead to gear teeth bending fatigue failure due to repeated higher bending stresses. In this paper, a study related to how to reduce overall product development time by simulating bending fatigue failure of gear in lab environment is presented. A systematic approach is used
Gear whine has emerged as a significant challenge for electric vehicles (EVs) in the absence of engine masking noise. The demand from customers for premium EVs with high speed and high torque density introduces additional NVH risks. Conventional gear design strategies to reduce the pitch-line velocity and increase contact ratio may impact EV torque capacitor or its efficiency. Furthermore, microgeometry optimization has limited design space to reduce gear noise over a wide range of torque loads. This paper presents a comprehensive investigation into the optimization of transfer gear blanks in a single-speed two-stage FDW electric drive unit (EDU) with the objective of reducing both mass and noise. A detailed multi-body dynamics (MBD) model is constructed for the entire EDU system using a finite-element-based time-domain solver. This investigation focuses on the analysis and optimization of asymmetric gear blank design features with three-slot patterns. A design-of-experiment (DOE
In addition to providing safety advantages, sound and vibration are being utilized to enhance the driver experience in Battery Electric Vehicles (BEVs). There's growing interest and investment in using both interior and exterior sounds for pedestrian safety, driver awareness, and unique brand recognition. Several automakers are also using audio to simulate virtual gear shifting of automatic and manual transmissions in BEVs. According to several automotive industry articles and market research, the audio enhancements alone, without the vibration that drivers are accustomed to when operating combustion engine vehicles, are not sufficient to meet the engagement, excitement, and emotion that driving enthusiasts expect. In this paper, we introduce the use of new automotive, high-force, compact, light-weight circular force generators for providing the vibration element that is lacking in BEVs. The technology was developed originally for vibration reduction/control in aerospace applications
This paper describes an optimal control method utilizing a Linear Quadratic Regulator (LQR) to control the torque during the gear shift on a multispeed electrified transmission to optimize for clutch actuator durability and shift performance. The dynamic state-space model of the system has been obtained using System-Identification. An LQR controller is formulated to minimize driveline oscillations and transmission-input-torque using the model by manipulating the electrical torque applied by the traction motor at the transmission input. The LQR controller is implemented in a simulation framework wherein the impact of vehicle parameters on the shift quality metrics is also assessed. Subjective and objective requirements are considered in the tuning process for the LQR controller. The LQR controller is utilized to generate profiled torque table calibrations. These calibrations are then deployed onto a production ready Transmission Control Unit and experimentally validated on a Class-8
This paper focuses on the weak fault diagnosis of a dual - axes precision gear transmission system. Firstly, it elaborates on the structure and working principle of the system. Comprising components like azimuth and pitch channels, motors, and control units, the pitch channel's gear transmission chain is a key research area. Subsequently, fault modes and their harmfulness are analyzed. Different faults such as tooth surface wear and pitting are considered. These faults can lead to serious consequences like system failure and mission deviation. Based on this, a test system is constructed. It includes sensors and a data acquisition system to simulate faults and collect vibration signals. The signals are then analyzed to understand the system's behavior. Finally, a weak fault feature index based on time - domain entropy is developed. A threshold setting method based on severity index is also proposed. These methods together enable the accurate diagnosis of weak faults in the system, which
Gear shifting effort or force especially in manual transmission has been one of the key factors for subjective assessment in passenger vehicle segment. An optimum effort to shift into the gears creates a big difference in overall assessment of the vehicle. The gear shifting effort travels through the transmission shifting system that helps driver to shift between the different available gears as per the torque and speed demand. The shifting system is further divided into two sub-systems. 1. Peripheral system [Gear Shift Lever with knob and shift Cable Assembly] and Shift system inside the transmission [Shift Tower Assembly, Shift Forks, Hub and sleeve Assembly with keys, Gear Cones and Synchronizer Rings etc.] [1]. Both the systems have their own role in overall gear shifting effort. There has been work already done on evaluation of the transmission shifting system as whole for gear shifting effort with typical test bench layouts. Also, work has been on assessment of life of the
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