Research on the dead-point problem of spherical micro pump based on virtual prototype

Proceedings of the Institution of Mechanical Engineers, Part J:

Han

et al. 2021

In this paper, the dynamic contact characteristics between a piston system and a cylinder block in a spherical pump are studied theoretically and numerically. The theoretical contact model between a piston and a cylinder is established based on its structural and operational properties, to obtain the maximum contact force quantitatively. The effects of different structural parameters and working pressures on the contact force are analyzed and discussed. The relationship between friction coefficient and rotation speed is presented. The contact pairs are modeled numerically using the finite-element method and augmented Lagrange algorithm to obtain both the tangential and normal contact characteristics. Both static and dynamic contact characteristics of the piston are analyzed and discussed. These proposed studies can provide practical suggestions on improving the wear resistance performance and durability of the spherical pump.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical modeling and numerical simulation of dynamic contact characteristics of a spherical pump with variable friction coefficient

Proceedings of the Institution of Mechanical Engineers, Part J:

Han

et al. 2021

“…A spherical pump is illustrated in Figure 1. It presents the advantages of small size, high-power density, low noise and vibration emission (Guan et al , 2018a; Guan et al , 2018b; Guan et al , 2019b; Guan et al , 2018c; Guan et al , 2016; Niu et al , 2016; Wu et al , 2016). However, because of conformal contact between its rotor system and cylinder, a large contact area enhances friction between these contact pairs.…”

Section: Introductionmentioning

confidence: 99%

Frictional moment and wear modelling for incomplete spherical pistons in a spherical pump

2022

ILT

Purpose Because of the specific structure and working mechanism, piston speed is only half of its shaft, which causes severally friction between piston and cylinder. Therefore, the main purpose of this paper is to investigate the friction and wear characteristics of the incomplete spherical piston in spherical pump comprehensively. Finally, to search the low-friction and wear-resistance structural pattern of the piston, and enhance the durability of spherical pump. Design/methodology/approach The non-linear frictional moment model for incomplete spherical piston in spherical pump was derivated quantificationally. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The theoretical wear model of piston–cylinder pair is proposed as well. Findings To reduce the frictional moment between incomplete piston and cylinder, the optimised diameter ratio between piston pin and piston should be 0.12 based on the parameter sensitivity analyses. The maximum frictional moment is approximately 2.5 times of the minimum. The total efficiency should be considered synthetically based on the thickness of specific working medium. Originality/value The proposed non-linear frictional moment model offers the quantitative estimations. Parameter sensitivity analyses were conducted to find the low-friction structural pattern of the piston. The wear behaviours of the piston and cylinder were analysed to investigate the wear characteristics of the piston.

“…Different from the traditional hydraulic pumps (Ma et al, 2014), spherical pump is a new concept of positive displacement pump whose discharge pressure is between the gear pump and piston pump (Guan et al, 2016;Guan et al, 2018a;Guan et al, 2018b;Guan et al, 2018d;Guan et al, 2018c;Wu et al, 2016;Niu et al, 2016). Spherical pump has the properties of compact, lightweight, low noise and slight vibration as a result from no reciprocating parts (Guan et al, 2015c;Guan et al, 2015b;Guan et al, 2015a).…”

Section: Introductionmentioning

confidence: 99%

Friction and wear modeling of rotary disc in spherical pump

Gong

et al. 2019

ILT

Purpose Rotary disc is a key component in the compact spherical pump, connecting shaft and piston, bearing hydraulic force conformally and constituting dynamic working chambers alternatively. Motion of rotary disc comprises two components. One is rotating around its own axis and the other is sliding on a cone surface. Therefore, it is necessary to investigate the friction and wear mechanism between rotary disc and cylinder under a complicated operation condition. Design/methodology/approach Structural properties of rotary disc are analyzed first. Frictional moment of rotary disc is modeled based on its structural characteristics and working mechanism, and the constraints of the structural parameters are considered. Besides, the concept of dimensionless contact area is proposed. Comparison is performed between the proposed concept and the frictional moment to determine an optimized beginning angle for spherical pump with a given displacement. The wear model of rotary disc is also established based on its kinematic property, a velocity coefficient is proposed and its common values are presented. Findings Effects of structural parameters, i.e. beginning angle and ending angle on the frictional moment, are obtained quantitatively. The frictional moment increases with beginning and ending angle with different rates. While the dimensionless contact area decreases with beginning angle. The larger the piston angle, the larger the velocity coefficient will be. The rotary disc wears severely with a larger beginning angle and smaller ending angle, while it has the smallest wear rate under a smaller beginning angle and a larger ending angle. Originality/value The originality lies in modeling the complex contact force of rotary disc based on its specific structure. These conclusions can be used to optimize the structural parameters of rotary disc.