Lubrication characteristics of the worn slipper in the slipper-swashplate pair

Purpose This paper proposes the lubrication characteristics of the worn slipper in the slipper–swashplate pair. The mathematical analysis of lubrication characteristics of slipper with the measured surface roughness distribution is introduced. Based on the results from the test rig, it carries out the result compassion in different operating conditions. Design/methodology/approach This paper introduces the measured surface roughness distribution of new and used slippers and generates the oil film thickness distribution with it. An average flow Reynolds equation of the pressure distribution is introduced too. The experimental results are carried out on a novel adjustable oil film thickness test rig. Findings The surface roughness of the worn slipper enlarges the reacting force and torque only if the oil film thickness is small. When the ratio of oil film thickness to the root mean square of surface roughness is much smaller than 3, the influence of it on torque is obvious. Originality/value Different surface roughness of worn slipper proposed in this paper has an influence on the lubrication characteristics. As the slipper is worn after a period of use, the changed lubrication characteristics should be considered in the slipper design.

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An adjustable oil film thickness test rig for detecting lubrication characteristics of slipper/swash-pair in piston pumps

Industrial Lubrication and Tribology ◽

10.1108/ilt-05-2020-0166 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Haiji Wang ◽

Guanglin Shi

Keyword(s):

Film Thickness ◽

Peer Review ◽

Relative Error ◽

Mathematical Analysis ◽

Test Rig ◽

Content Type ◽

Oil Film ◽

Displacement Sensors ◽

Measuring Machine ◽

Lubrication Characteristics

Purpose The purpose of this paper is to propose an adjustable oil film thickness test rig for detecting lubrication characteristics of the slipper. The mathematical analysis of lubrication is introduced. Based on the results from the test rig, the results comparison from test rig and mathematical analysis is carried out. Design/methodology/approach This paper introduces a mechanism which can adjust the oil film thickness between the slipper and swash-plate. Feasibility is ensured, and the accuracy of test rig is guaranteed by the three-coordinate measuring machine. Three displacement sensors show the oil film thickness and its shape. The reacting force and torque resulting from oil film can be achieved by three S-type force sensors and a torque sensor, respectively. Findings The relative error of the reacting force is small. The relative error reduces and is acceptable when the deformation of retainer is taken into account. The thickness and tilt angle of oil film have less effect on the reacting force. However, they are significantly impact on torque. Originality/value The test rig proposed in this paper is able to adjust the oil film thickness, which is used to detecting the lubrication characteristics in pump design. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0166/

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Dynamic transmission of oil film in soft-start process of HVD considering surface roughness

Industrial Lubrication and Tribology ◽

10.1108/ilt-01-2017-0002 ◽

2018 ◽

Vol 70 (3) ◽

pp. 463-473 ◽

Cited By ~ 4

Author(s):

Fangwei Xie ◽

Jie Zhu ◽

Jianzhong Cui ◽

Xudong Zheng ◽

Xinjian Guo ◽

...

Keyword(s):

Surface Roughness ◽

Film Thickness ◽

Friction Pair ◽

Maximum Temperature ◽

Force Model ◽

Content Type ◽

Oil Film ◽

Soft Start ◽

Viscous Torque ◽

Start Process

Purpose The purpose of this paper is to study the dynamic transmission of the oil film in soft start process of hydro-viscous drive (HVD) between the friction pairs with consideration of surface roughness, and obtain the distribution law of temperature, velocity, pressure, shear stress and viscous torque of the oil film. Design/methodology/approach The revised soft-start models of HVD were derived and calculated, including average Reynolds equation, asperity contact model, load force model and total torque model. Meanwhile, a 2D model of the oil film between friction pair was built and solved numerically using computational fluid dynamics (CFD) technique in FLUENT. Findings The results show that the maximum temperature gradually reduces from the intermediate range (z = 0.5 h) to the inner side of the friction pair along the direction of oil film thickness. As the soft-start process continues, pressure gradient along the direction of the oil film thickness gradually changes to zero. In addition, tangential velocity increases and yet radial velocity decreases with the increase of the radius. Originality/value In this paper, it was found that the viscous torque calculated by the numerical method is smaller than that by the CFD model, but their overall trend is almost the same. This also demonstrates the effectiveness of the numerical simulation.

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Measurement and calculation of oil film thickness in a ball bearing

Industrial Lubrication and Tribology ◽

10.1108/ilt-11-2016-0265 ◽

2018 ◽

Vol 70 (8) ◽

pp. 1500-1508 ◽

Cited By ~ 2

Author(s):

Baogang Wen ◽

Hongjun Ren ◽

Pengfei Dang ◽

Xu Hao ◽

Qingkai Han

Keyword(s):

Film Thickness ◽

Ball Bearing ◽

Performance Indicator ◽

Thickness Distribution ◽

Content Type ◽

Oil Film ◽

Capacitance Method ◽

Lubrication Condition ◽

Series Of Experiments ◽

External Loads

PurposeThe oil film thickness provides a key performance indicator of a ball bearing lubrication condition. This paper aims to propose an approach to calculate and measure the oil film thickness of the bearing.Design/methodology/approachOn a specially designed test rig, measurement of the capacitance is used to monitor the oil film thickness of ball bearing. A corrected film thickness formula taking account of the influences of non-Newtonian shear thinning and thermal is introduced to predict the oil film thickness of ball bearing. And then the film thickness distribution and the corresponding capacitances are calculated.FindingsMeasurement and calculation of oil film thickness in a ball bearing are carried out under various rotating speeds and external loads. By comparing the calculated capacitances with measured results, it can be concluded that the calculated results obtained by the amended film thickness formula are much closer to the test findings than the classical computed values according to Hamrock–Dowson.Originality/valueA new corrected film thickness formula is introduced in predicting oil film thickness of ball bearing and verified by the series of experiments according to capacitance method.

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Effect of torque ratio on speed regulating start

Industrial Lubrication and Tribology ◽

10.1108/ilt-02-2018-0062 ◽

2018 ◽

Vol 70 (9) ◽

pp. 1657-1663

Author(s):

Qingrui Meng ◽

Zhao Chenghao ◽

Tian Zuzhi

Keyword(s):

Film Thickness ◽

Theoretical Basis ◽

Design Methodology ◽

Load Capacity ◽

Load Torque ◽

Content Type ◽

Oil Film ◽

Torque Transmission ◽

Drive Speed ◽

Starting Process

Purpose Friction pairs of the hydro-viscous drive speed regulating start device should be designed based on the rated torque. To obtain design basis of the rated torque of the hydro-viscous drive speed regulating start device, studies on effect of torque ratio (a ratio of the load torque to the rated torque) on speed regulating start were carried out theoretically and experimentally. Design/methodology/approach Under different torque ratio, the modified Reynolds, the thermal energy and the viscosity-temperature equations were solved simultaneously by using finite element method to reveal variation laws of the oil film load capacity and torque transmission during the starting process. Then, speed regulating start experiments were carried out to study the following performance of the output speed. Findings The results show that oil film thickness decreases with the increase of the torque ratio; when oil film thickness is less than 0.05 mm, oil film temperature increases rapidly with the decrease of oil film thickness, which eventually deteriorates performance of the speed regulating start; when the torque ratio decreases to about 0.3, output speed shows a better following performance. Originality/value It indicates that, to acquire a better speed regulating start, the rated torque of the hydro-viscous drive speed regulating start device should not be less than three times of the load torque. Achievements of this work provide theoretical basis for optimal design of the friction pairs of the hydro-viscous drive speed regulating start device.

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