The purpose of this paper is to reveal the mechanism of effect of surface groove on speed‐regulating start.
Abstract
Purpose
The purpose of this paper is to reveal the mechanism of effect of surface groove on speed‐regulating start.
Design/methodology/approach
This paper investigates numerically and analytically the torque transfer and load capacity of oil film between separator and friction disc with grooves commonly used at present by solving simultaneous equations: modified Reynolds, energy, and temperature‐viscosity equations.
Findings
The results show friction discs with wider and deeper groove are not suitable for speed‐regulating start. To improve performance of speed‐regulating start, distribution and size of surface groove should be designed to obtain ascending trend of oil film load capacity during startup process.
Originality/value
This paper reveals the mechanism of effect of surface groove on speed‐regulating start and facilitates the conceptual design of speed‐regulating start control system.
Details
Keywords
Daoming Wang, Youfu Hou, Zuzhi Tian and Qingrui Meng
This study aims to reveal the temperature rise characteristic of magnetorheological (MR) fluid in a multi-disc MR clutch under slip condition, including the temperature…
Abstract
Purpose
This study aims to reveal the temperature rise characteristic of magnetorheological (MR) fluid in a multi-disc MR clutch under slip condition, including the temperature distribution regularity and the impact factors.
Design/methodology/approach
Three-dimensional transient heat conduction equation for the MR fluid in the working gap was derived based on the heat transfer theory. Then, numerical simulation was conducted to analyze the temperature field of MR fluid. Furthermore, an experimental study was performed to explore the temperature distribution of the MR fluid in radial and circumferential directions, as well as the effects of disc groove, slip power and gap size on temperature rise characteristic of the MR fluid.
Findings
The results show that temperature appears to be largest in the center of the working gap and the temperature difference increases with the slip time. However, the temperature field in a circumferential direction is basically the same, but it presents slightly lower in the groove area. The temperature of the MR fluid increases linearly with the slip time and the rise rate increases with the slip power. Moreover, the temperature rise value decreases with the increase of gap size.
Originality/value
In this paper, the temperature gradients, both in radial and circumferential directions, are experimentally measured going beyond the estimation by computer simulations. In addition, the factors that influence the temperature rise characteristic of MR fluid were fully analyzed. The results could provide a reliable basis for the development of cooling technology for high-power MR devices.
Details
Keywords
Fangwei Xie and Youfu Hou
The purpose of this paper is to reveal the characteristics of hydrodynamic load capacity and torque transferred by oil film with variable viscosity, and the effect of groove…
Abstract
Purpose
The purpose of this paper is to reveal the characteristics of hydrodynamic load capacity and torque transferred by oil film with variable viscosity, and the effect of groove number, width and depth on the hydrodynamic load capacity and torque transfer.
Design/methodology/approach
The radial temperature of friction pair and viscosity of YLA‐N32 hydraulic oil were measured through experiments, and a viscosity‐diameter expression was deduced using polynomial fitting method. Analytical expressions for hydrodynamic load capacity and torque of the oil film were deduced based on hydrodynamic lubrication theory.
Findings
The investigation shows the hydrodynamic load capacity and transferred torque with variable viscosity are much less than that with constant viscosity. Load capacity increases with the increase of groove depth which is the most significant influence factor, while it has the least influence on torque. Groove width has great influence on load capacity and torque. The load capacity increases with the increase of groove width; contrarily, torque decreases with the increase of groove width. Groove number has little influence on load capacity, while it has great influence on torque. The torque decreases with the increase of groove number.
Originality/value
In this paper, analytical solutions for hydrodynamic load capacity and torque of the oil film with variable viscosity are deduced. The paper reveals the relationship between hydrodynamic load capacity, torque transfer and groove number, width and depth.