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Article
Publication date: 10 August 2018

Xibing Li, Weixiang Li, Xueyong Chen, Ming Li, Huayun Chen and Xin Yue

The purpose of this paper is to examine the effect of application of a heat pipe in an aspect of hydrostatic thrust bearings on thermal balance and deformation and the role of…

Abstract

Purpose

The purpose of this paper is to examine the effect of application of a heat pipe in an aspect of hydrostatic thrust bearings on thermal balance and deformation and the role of this application in increasing the rotating speed of a workbench.

Design/methodology/approach

Numerical simulations of oil film temperature field, the temperature field and thermal deformation of the bearing’s workbench and base were performed by finite element analysis (FEA) software for both the traditional hydrostatic thrust bearings and the heat pipe ones.

Findings

Oil pad and workbench of the hydrostatic thrust bearings are fabricated with a heat pipe cooling structure, which can take away most of the heat generated by shearing of the oil film, control the temperature rise and thermal deformation of the hydrostatic thrust bearing effectively, avoid the dry friction phenomenon and finally improve the processing quality of equipment.

Originality/value

The heat pipe hydrostatic thrust bearings could control the temperature rise and thermal deformation of the hydrostatic thrust bearing effectively, avoid the dry friction phenomenon and improve the processing quality of equipment.

Details

Industrial Lubrication and Tribology, vol. 70 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 11 April 2016

Xibing Li, Tian Cheng, Ming Li, Mingjian Li, Ruren Wu and Yingsi Wan

This paper aims to research the lubrication performance of large-size rectangular oil pad in hydrostatic thrust bearing for heavy computer numerical control (CNC) vertical lathe.

Abstract

Purpose

This paper aims to research the lubrication performance of large-size rectangular oil pad in hydrostatic thrust bearing for heavy computer numerical control (CNC) vertical lathe.

Design/methodology/approach

The research establishes the mathematical models of velocity, flux and pressure fields, etc., for lubrication performance distribution, and analyzes its load-bearing behavior.

Findings

When hydrostatic thrust bearing’s rotating speed is within ω12, the oil flow generated by plate’s relative motion is greater than that generated by pressure difference and centrifugal force, and in the opposite direction, making it not easy to emit friction heat, so the rotating speed range ω12 should be avoided for bearing.

Originality/value

The research provides powerful theoretical basis for the structure design, operating reliability and practical application of large size rectangular oil pad hydrostatic thrust bearing, and realizing the prediction of its lubrication performance.

Details

Industrial Lubrication and Tribology, vol. 68 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 10 July 2017

Xibing Li, Tian Cheng, Ming Li, Mingjian Li, Ruren Wu and Yingsi Wan

The purpose of this study with the rapid development of the heavy/large mechanical equipment, the heavy computer numerical control (CNC) vertical lathe has become the ideal…

Abstract

Purpose

The purpose of this study with the rapid development of the heavy/large mechanical equipment, the heavy computer numerical control (CNC) vertical lathe has become the ideal processing equipment for the parts of those mechanical equipments. The main factor which affects the machining quality and efficiency of heavy CNC vertical lathe is the mechanical properties of the hydrostatic thrust bearing.

Design/methodology/approach

This paper did the research based on the large size sector oil pad’s lubrication performance of the hydrostatic thrust bearing in the heavy/large equipments, establishing the lubrication performance distribution mathematical model of the velocity field, flow field, pressure field and so on, analyzing the bearing behavior of the large size sector oil pad.

Findings

The results show that the oil flow generated by the plate relative motion will be greater than that generated by the pressure difference in area B, with the rotational speed’s increasing of the hydrostatic thrust bearing, and the direction is opposite. The oil flow generated by the centrifugal force will be greater than that generated by the pressure difference in area C, with the rotational speed’s increasing of the hydrostatic thrust bearing, and the direction is opposite. When the rotational speed of the hydrostatic thrust bearing is too high, the friction heat will be not easy to be sent out. The bearing rotating speed should be lower than the comparatively smaller one of ω1 and ω2, which can help avoid the rise of too high temperature.

Originality/value

The research provides powerful theoretical foundation for practical application of the large size sector oil pad hydrostatic thrust bearing, its structure design and operating reliability, realizing the lubrication performance prediction of the large size hydrostatic thrust bearing.

Details

Industrial Lubrication and Tribology, vol. 69 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 14 September 2012

James Taylor

The purpose of this paper is to discuss some of the implications of policies, practices and new “non‐equilibrium” management approaches in mobile grassland management.

Abstract

Purpose

The purpose of this paper is to discuss some of the implications of policies, practices and new “non‐equilibrium” management approaches in mobile grassland management.

Design/methodology/approach

The author takes an actor‐oriented perspective on the narrative of land‐use practices, notional sustainable stocking rates and the problematic of state policy interventions in local context. The paper is based on two years in the field on a bilateral aid‐funded grassland management project at Xing'an League, Inner Mongolia and follow‐up among selected informants.

Findings

The constitution of grasslands “degradation” is in fact contested by resource users. Most grassland scientists, Party and Government officials in China have tended to associate ethnic “minority” mobile pastoralists with destructive cultural practices that, they argue, have led to ecological decline on the steppes. This argument is integral to the “degradation narrative” that underpins the discourse on grassland science. The conventional bio‐ecology emphasis on species dominance (growth‐form), in fact says little about the extent of anthropogenic impacts on above‐ground biomass and whether these factors have been the cause of degradation. The paper suggests that greater consideration is given to specific changes in human activity, climatic and plant productivity over time and space, based on endogenous, flexible seasonal estimates.

Research limitations/implications

Although presenting challenges to conventional grassland science based on endogenous experiences and herder practices, it may have specific geopolitical limits to more general scaling‐up in different contexts.

Practical implications

The paper discusses new modalities of non‐equilibrium grassland management, inverting normative top‐down approaches to controlling environmental degradation, livestock distribution and stocking rates.

Social implications

The paper suggests rethinking the use of customary practices, vernacular knowledge and the social organisation of herders in the design of sustainable grassland management.

Originality/value

The paper may be valuable to practitioners, rural development planners, funders and researchers interested in the use of integrated, cross‐disciplinary, new ecological knowledge in grassland management.

Details

International Journal of Development Issues, vol. 11 no. 3
Type: Research Article
ISSN: 1446-8956

Keywords

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