Shyh-Ming Jong

Bio: Shyh-Ming Jong is an academic researcher. The author has contributed to research in topics: Conical surface & Bearing (mechanical). The author has an hindex of 1, co-authored 2 publications receiving 4 citations.

Static analysis of hydrostatic conical bearings using flow resistance network method

Abstract: Purpose – This paper aims to study the static characteristics of the hydrostatic conical journal bearings by utilizing single-action membrane restrictors to compensate the working pressures of recesses. Design/methodology/approach – The flow resistance network method is used to analyze the influences of load capacity and static stiffness of bearing with the design parameters, including the number of recesses, radial eccentricity ratio, axial displacement ratio, restriction constant, membrane compliance, length-diameter ratio, circumferential land width ratio, axial land width ratio and half of cone angle. Findings – This study shows the infinite stiffness of the oil produced in the first and second recesses while single-action membrane restriction constant of 2 and 3, respectively, as well as in the fourth recess while single-action membrane restriction constant of 0.01 and 0.1, respectively. Research limitations/implications – This article provides the hydrostatic conical bearings in static and unbiased ...

An implementation of FPGA based driver for approaching high resolution of five-phase hybrid step motor

Abstract: Hybrid step motor is one of the primary candidates for direct drive motor due to its high torque and low speed, but the vibration it produces is a major drawback to use it in applications. The micro-step method is typically used to reduce the vibration and to obtain high resolution motor steps, which divides a single step into many micro-steps. PWM (Pulse Width Modulation) is the most common method to control the micro-step motor, but the equivalent magnetic circuit taking into account the localized saturation throughout the hybrid step motor is a non-linear model. This paper presents the development of a non-linear FPGA based driver for controlling five-phase hybrid step motor. The application circuit we developed is aimed for use in a low cost system. Simulations were done, and circuit analysis tests were carried out to verify our design, using prototype circuit boards. Low vibration and high resolution steps are achieved by using our nonlinear micro-step control method.

Application of dynamic mesh technology in the oil film flow simulation for hydrostatic bearing

Abstract: Purpose The purpose of this paper was to obtain the lubrication characteristics of heavy hydrostatic bearing in heavy equipment manufacturing industry through theoretical analysis and numerical simulation. Design/methodology/approach This paper discusses the influence of oil film thickness variation on velocity field, outlet-L and outlet-R flow velocity under the hydrostatic bearing running in no-load 0 N, load 400 KN, full load 1,500 KN and rotating speeds of 10 r/min, 20 r/min, 30 r/min, 40 r/min, 50 r/min and 60 r/min, by using dynamic mesh technology and FLUENT software. Findings When the working table rotates clockwise, in the change process of oil film thickness, the fluid flow pattern of the lubricating oil at the edge of the sealing oil is the rule of laminar flow, and the oil cavity has a vortex. The outlet-R flow velocity becomes higher and higher by increasing the bearing load and working table speed, and the flow velocity increases with the decrease in oil film thickness; the outlet-L flow velocity increases with the decrease in oil film thickness under low rotating speed (less than 10 r/min) condition and decreases with the decrease of oil film thickness under high rotating speed (more than 60 r/min) condition. Originality/value The influence of the oil film thickness on the flow state distribution of the oil film was analyzed under different working conditions, and the influence rules of oil film thickness on the flow velocity of hydrostatic bearing oil pad was obtained by using dynamic mesh technology.

An improved lumped parameter method for calculating static characteristics of multi-recess hydrostatic journal bearings:

Abstract: This paper proposes an improved lumped parameter method for calculating the static characteristics of multi-recess hydrostatic journal bearings. The improved lumped parameter method can estimate th...

Multi-objective analysis design of spiral groove conical bearing considering cavitation effects

Abstract: As the element of rotary motion, the evaluation of hydrodynamic behavior for spiral groove conical bearing (SGCB) is related with the stability of multibody systems and the influence of cavitation on the lubrication performance of SGCB is an important concern. This work presents a computational method for design of groove in the different operation conditions, considering multi-objective analysis. With the cavitation effects taken into account, the hydrodynamic behavior of SGCB is calculated with multiphase flow model accounting for phase transition process and cavitation phenomenon. Moreover, the numerical results are compared with the published test data and the maximum deviation between simulation and experiment is 6.63%, which demonstrates the validity of proposed model. Then, the detailed analysis of hydrodynamic response for SGCB is conducted, which represents that a suitable design of groove parameters would provide a better lubrication performance of SGTB. • The multiphase flow model is established for the evaluation of SGCB in high speed condition. • The groove shapes are different for the optimal lubrication performance. • The hydrodynamic behavior and cavitation volume fraction changes with the variation of structural parameters of groove. • We report a reference for SGCB design considering the multi-objective analysis.

Pad attitude adjusting moment in large multi-pocket pivoted pad used in static oil journal bearing

Abstract: Purpose Large scale is a trend of the ball mill, so the loads on their bearings become very large, bearing operating conditions turn into more severe. The moment of inertia to their pivot of the pad increase significantly, so it leads to the difficult of the pad attitude adjustment and makes the pad tilting angles time response slow, the key factor to effects attitude adjustment is the oil film moment to the pad pivot at unbalance position. the oil film moment and its effect factors must be studied in the design of the bearing used in ball mill. Design/methodology/approach Models about the lubrication of multi-pocket pivoted pad hydrostatic bearing is established, the complicated relationship of the oil flow rate between the oil pockets are taken into account. Finite differential method is used to solv the model, and theroy of finite element method is use to calculate the oil flow rate out of the pocket edges. Newton’s methods are used to determine the pressure of pockets.The pad tilting moment to its pivot is numerically analyzed. Findings The tilting moment to its pivot is set as an indicator of the ability for a pad to adjust its attitude. The effects of the diameter of throttling capillary and the pocket area on the attitude adjusting capacity is studied. Relations between the attitude adjustment capacity for a pad and there effects factors are presented. Practical implications The methods and results have the special reference to the design and operation of multiple pockets tilted pad hydrostatic journal bearing. Originality/value Methods to studied the pad attitude adjustment are given in the article for the multi-pocket pivot pad hydrostatic beairng.The influence factors on pad attitude adjusting capacity are discussed for a this specail kind hydrostatic bearing, the how the factors influence the pad tilting angle adjustment are presented.