Cam Ring Research Articles

Modeling and experimental validation of twin lip balanced vane pump considering micromotions, contact mechanics, and lubricating interfaces

This paper presents a model formulation for balanced twin lip vane pumps and an experimental activity to validate the model. The simulation model begins with a geometrical module that preprocesses the CAD drawings of a given unit. The model then performs a fluid dynamic analysis using a lumped-parameter formulation to solve for the pressures inside properly defined control volumes within the unit. The fluid dynamic model is solved simultaneously with a motion module that evaluates the planar motions of the vanes using Newton’s law of motion and with a lubricating interface solver based on the Reynolds equation. Contact dynamics formulations and elastohydrodynamic relations are applied at the vane locations in contact with the cam ring. The comparison with experimental results highlights a good match in volumetric and hydromechanical efficiencies. The measured outlet pressure ripple matches the simulated one for all tested speeds and pressures. The paper also shows a breakdown of the distribution of volumetric and power losses arising from various components of the machine. The proposed methodology is computationally inexpensive, so it can be used in future design and optimization studies aimed at improving the performance of such units.

Parameter Optimization of Vibration Reduction Structure for Low-Speed, Multi-Acting Cam Ring Motor

Parameter Optimization of Vibration Reduction Structure for Low-Speed, Multi-Acting Cam Ring Motor

ZLDI-8 suppresses angiogenesis and vasculogenic mimicry in drug-resistant NSCLC in vitro and in vivo

AimsThe chemotherapy drugs for NSCLC often face the consequences of treatment failure due to acquired drug resistance. Tumor chemotherapy resistance is often accompanied by angiogenesis. Here, we aimed to investigate the effect and underlying mechanisms of ADAM-17 inhibitor ZLDI-8 we found before on angiogenesis and vasculogenic mimicry(VM) in drug-resistant NSCLC. Main methodsThe tube formation assay was used to evaluate angiogenesis and VM. Migration and invasion were assessed with transwell assays in the co-culture condition. To explore the underlying mechanisms of how ZLDI-8 inhibited tubes formation, ELISA assay and western blot assay were preformed. The effects of ZLDI-8 on angiogenesis in vivo were investigated in Matrigel plug, CAM and Rat aortic ring assays. Key findingsIn the present study, ZLDI-8 significantly inhibited the tube formation of human umbilical vein endothelial cells (HUVECs) in either normal medium or in tumor supernatants. Furthermore, ZLDI-8 also inhibited VM tubes formation of A549/Taxol cells. In the co-culture assay, the interaction between lung cancer cells and HUVECs promotes increased cell migration and invasion, while ZLDI-8 eliminates this promotion. Moreover, the VEGF secretion were decreased by ZLDI-8 and the expression of Notch1, Dll4, HIF1α and VEGF were inhibited by ZLDI-8. In addition, ZLDI-8 can inhibit blood vessel formation in the Matrigel plug, CAM and Rat aortic ring assays. SignificanceZLDI-8 inhibits angiogenesis and VM in drug-resistant NSCLC through suppressing Notch1-HIF1α-VEGF signaling pathway. This study lays the foundation for the discovery of drugs that inhibit angiogenesis and VM in drug resistant NSCLC.

Deformation pre-compensated optimization design of cam ring for low pulsation hydraulic motors

Deformation pre-compensated optimization design of cam ring for low pulsation hydraulic motors

Computational Fluid Dynamics Modeling of Gaseous Cavitation in Lubricating Vane Pumps: On Metering Grooves for Pressure Ripple Optimization

Abstract This paper addresses the topic of balanced vane pump simulations for pressure ripple optimization by means of metering grooves at the leading edge of delivery ports. It presents a computational fluid dynamics case study based on a transient three-dimensional model developed using an up-to-date commercial software tool. Special attention is dedicated to gaseous cavitation and the impact of the related modeling choices on predictions. The effect of groove dimensions and interaction with the precompression features of the cam ring of the pump are addressed. Experimental data obtained using a dedicated test rig are presented for comparison with numerical results in terms of delivery pressure ripple and volumetric flowrate. A validation strategy based on tuning of the dynamic cavitation model adopted for simulations is proposed. The results demonstrate the critical importance of gas release modeling for the simulation of porting details in the case of significant aeration effects.

Design and Dynamic Analysis of the Recirculating Planetary Roller Screw Mechanism

The recirculating planetary roller screw mechanism (RPRSM) is a transmission mechanism that engages the screw and nut threaded by multiple grooved rollers. In this paper, firstly, the design method of RPRSM nut threadless area is proposed, and the equations related to the structural parameters of nut threadless area are derived. On this basis, the cross-section design method of roller, screw and nut is constructed according to the actual situation of engagements between the screw/nut and the roller. By adjusting the gap between the two beveled edges and that between the arc and the beveled edge, the accuracy of the thread engagements between the screw/nut and the roller can be improved. Secondly, to ensure the engagements of the screw/nut and the roller, the distance equation from the center surface of the different rollers to the end surface of cam ring is given. Thirdly, combined with the working principle and structural composition of RPRSM, the component model is established according to its relevant structural parameters, and the virtual assembly is completed. Finally, the 3D model is imported into the ADAMS simulation software for multi-rigid body dynamics. The dynamic characteristic is analyzed, and the simulated values are compared with the theoretical values. The results show that the contact forces between the screw/nut and the roller are sinusoidal, mainly due to the existence of a small gap between the roller and the carrier. The maximum collision forces between the roller and cam ring are independent from load magnitude. Normally, the collision force between the roller and the carrier increases as the load increases. When RPRSM is in the transmission process, the roller angular speed in nut threadless area begins to appear abruptly, and the position of the maximum change is at the contact between the roller and the convex platform of cam ring. The design of the nut threadless area and the proposed virtual assembly method can provide a theoretical guidance for RPRSM research, as well as a reference for overall performance optimization.

Numerical study on a rotational hydraulic damper with variable damping coefficient

The rotational hydraulic damper has advantages in the design and control of rotational machines. This paper presents a novel hydraulic rotational damper with the characteristic of adjusting the damping coefficient. It is composed of a shell, a gap, a rotor shaft, sliding vanes, a valve, and a motor, just like a combination of a sliding pump system and a valve driven by a motor. A new cam ring slot designed to guide the radial motion of sliding vanes could reduce friction resistance force, which will also benefit the design of the sliding pump. The damping coefficient model of this damper is established based on dynamic analysis. Series of numerical simulations validate the impact of factors on the damping coefficient. Frictional resistances have little influence on the damping coefficient during most conditions. The total coefficient is positively correlative with the angular velocity and the valve angle. Therefore, changing the valve angle according to the rotor shaft’s angular speed could adjust the damping coefficient.

Kinematics and geometrical admissibility conditions of balanced vane pumps with twin lip vanes

The present work is devoted to analyze the kinematics of twin lip vanes adopted in balanced vane pumps. The work provides the analytical description of the vane motion according to its geometrical parameters and the cam ring profile. Attention is given to the duality of the solution, an intrinsic property of twin lip vanes that may be considered as followers with two symmetrical half-circular tips. Based on the linkage kinematics, the analytical dissertation is further deepened to define the geometrical admissibility of the vane design and its mathematical domain. In order to evaluate the proposed approach, an extended parametric study is performed on the basis of the Buckingham theorem, detailing how the twin lip configuration affects the machine kinematics. Additional calculations are proposed to determine the vane design configurations that satisfy the fundamental law of cam design and to highlight how this requirement dramatically reduces the subset of available choices in presence of cam ring with a precompression profile. Finally, design guidelines are proposed in order to overcome these drawbacks and expand the admissibility domain.

Analysis of vane loads and motion in a hydraulic double vane pump with integrated electrical drive

In this paper, the results of the analysis of the forces acting on vanes in a double-acting vane pump with an integrated electric drive have been presented. In the new motor pump unit, the pump is assembled inside the rotor of the electric motor. A dynamic model representing the vane movement has been developed considering the impact of pressure load distribution, vane support forces and friction forces. The loss of contact between the vane head and the cam ring lead to the noise and reduction of the volumetric pump efficiency. The dynamic model which describes the vane motion and contact between the vane tip and cam ring has been solved using MATLAB software. The influence of load distribution, pump design and operational parameters on the vane dynamics has been analysed.

Analytical determination of the vane radial loads in balanced vane pumps

The present study proposes an analytical methodology to estimate the variable loads applied to the vanes of balanced vane pumps. The dissertation is adopted to detail the nature of the different time-varying excitations that load the machine and to define their analytical calculation on the basis of vane geometry, cam ring profile and working conditions. In this context, a dimensional reduction is proposed in order to highlight how the pump geometrical parameters affect each single force component and how they may be used to modify the ratio between each load contribution. A comprehensive overview of the mutual interconnections between time-varying loads and the pump design is provided by means of a parametric study involving vane design parameters, pump displacement and cam ring shape. Admissibility of the pump geometry is verified throughout the entire study. The results show that, given the cam ring shape, the vane design significantly influences the radial loads, which may also reach negative values and promote the vane detachment.

On the relation between vane geometry and theoretical flow ripple in balanced vane pumps

Advancements related to the correlation between pump design parameters and the kinematic flow ripple in balanced vane pumps are addressed in the present work. In particular, the study focuses the attention on the influence of the vane geometry on the oscillations of the flow rate produced by the volume variation of both under-vane pockets and displaced chambers, that is known as one of the most relevant sources of noise in hydraulic systems. The working principle of the machine is detailed and used as starting point to deduce analytical correlations describing both vane kinematics and delivery flow rate ripple. The set of results that can be achieved with the obtained formulation is evaluated by means of a nondimensional parametric study including the two main design parameters defining the vane geometry, i.e. thickness and tip radius. The resulting trends demonstrate that the theoretical delivery flow ripple is closely related to the vane design and the cam ring shape profile.

Geometric design and analysis of a novel sliding vane vacuum pump with three chambers

The cam ring profile greatly determines the pumping performance of the sliding vane vacuum pump (SVVP). In order to improve the performance of the SVVP such as increasing the suction volume under the condition of constant cylinder diameter, a novel type of SVVP with three chambers, called three-chamber sliding vane vacuum pump (TSVVP), was proposed, in which the sinusoidal spiral was used to generate the cam ring profile. A geometric model of the novel three-chamber cam ring profile was established. The design of the proposed TSVVP was explored after studying effects of the cam ring profile on the pumping speed and built-in volume ratio. Furthermore, the proposed TSVVP was compared with the conventional single-chamber and double-chamber SVVPs in terms of suction volume and volumetric utilization ratio. A prototype of the proposed STVVP was developed and experimental tests were carried out, which indicated that the results calculated by the proposed model were accorded with the experimental data. The study results show that the novel TSVVP is feasible and is also superior to the conventional SVVP with the single-chamber or double-chamber in terms of the pumping speed. The obtained data suggest key parameter values for the design of the novel TSVVP.

Kinematics of a balanced vane pump with circular tip vanes

This paper analyzes the kinematics of the vane-cam ring mechanism in balanced vane pumps, by considering both vanes with centered and not-centered circular tip. The motion of the vane, the position of the contact point and the evolution of the pressure angle are analytically determined in reference to a generic cam ring profile. The results of the kinematic analysis are used to obtain the constraints defining the admissibility of the vane geometry, which is described in terms of tip radius, vane thickness and tip center eccentricity. A parametric study is performed to show the capabilities of the proposed formulation and the influence of the vane design parameters on its kinematics. The analysis demonstrates that the vane kinematic motion in balanced vane pumps is mainly controlled by the tip radius and the tip center eccentricity, as long as the cam ring profile is defined. The tip radius is mainly responsible for the shape of the vane motion, while the tip center eccentricity has a major influence on its timing. Furthermore the effect of the cam ring profile is evaluated by demonstrating that shape and extension of the rise and fall phases influence on the vane geometry admissibility.

Development of Cam Ring Gear Parts of Large Diameter for Truck Clutch Using Hot–Cold Complex Forging Technology of Small Bar

Hot forging is a processing of plastic deformation for the metal at recrystallization temperature or higher. It is possible to decrease the flow stress and energy required to form the material at elevated temperature. But cold forging can improve mechanical properties, excellent dimensional accuracy, and surface quality. Main advantage of hot–cold complex forging is that it is able of large deformation with less force, and improved mechanical properties and dimensional accuracy. In general, complex forging for combining cold forging and hot forging of small bar can improve the shape accuracy of forged parts. In this study, the material loss and the production time were high in the conventional cutting process, but cam ring gear parts of large diameter for truck clutch were developed by applying the hot–cold forging technology. The complex forging technology of cam ring gear parts would be very useful to improve dimensional accuracy, reduce manufacturing cost, and increase die life.

Vibration and temperature variation of the cam ring of a hydraulic vane pump associated with vane tip detachment

Vibration and temperature variation of the cam ring of a hydraulic vane pump associated with vane tip detachment

Nonlinear Volume Flow Control of a Variable Displacement Vane Pump

AbstractVariable displacement vane pumps are used for mid‐pressure applications in a variety of systems. Due to their potential for power loss reduction they are most prominently featured in automotive applications. They provide a hydraulic consumer with varying levels of volume flow, depending on the eccentricity of the cam ring of the pump. Eccentricity control is typically achieved by means of hydraulic actuation. In this contribution, a model of a hydraulic aggregate featuring a VDVP with a nonlinear control technique based on input‐output‐linearization for volume flow tracking requirements is presented. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

RGM 기반 롤러 트랙 기어 시스템 설계

In recent years, RGM(roller gear mechanism) systems, wherein one of the gears of a meshing gear pair is replaced with pins or rollers, have been reintroduced, which is a consequence of, and therefore a reflection of, the rapid advances made in manufacturing technology. Three RTG(roller track gear) systems for arbitrary path transportation (e.g., L-, O-, U-, and S-shaped tracks) were constructed using two out of three RGM systems, namely, the CRP(cam rack pinion), CRG(cam ring gear), and RPG(roller pinion gear) systems, and are introduced in this paper. We also present three ways to prevent the intersection and non-contact phenomena at the teeth in the vicinity of the conversion point between two joined RGM systems.

Theoretical and Experimental Research on a Pressure-Reducing Valve for a Water Hydraulic Vane Pump

In order to control the high PV value between the vanes and the cam ring in a water hydraulic vane pump, a pressure-reducing valve with a constant pressure ratio was developed in this study. The pressure and leakage characteristics of the valve were theoretically analyzed by simulation and the experiments were also conducted based on the valve prototype. The theoretical analysis agrees well with the experimental results. Further, these results reveal that the pressure ratio of the valve decreases to the design value with the increasing working pressure. Additionally, the leakage of the valve rises simultaneously with the increasing working pressure and can be reduced significantly by decreasing the clearance between the valve body and the spool. The presented research not only proves the successful development of the pressure-reducing valve but also lays a foundation for the investigation of a high-pressure water hydraulic vane pump.

Optimization and Simulation on Pressure-Reducing Valve in Water Hydraulic Vane Pump

High contact stress between the vane tips and the cam ring is one of the main obstacles to improve the working pressure of a water hydraulic vane pump. A pressure-reducing valve for regulating the bottom pressure of the vanes at the pump suction zone is presented in this paper. Through optimization and simulation, it is found that the throttle structure has great influence on the dynamic performance of the pressure-reducing valve, and the triangular-rectangular groove is proved to be more suitable for the valve among all the investigated grooves. The theoretical analysis results show that the use of the pressure reducing valve can obviously reduce the contact forces between the cam ring and the vanes at the suction zone of the pump. The work in this research provides a feasible solution to improve the working pressure of a water hydraulic vane pump.

유압 베인 펌프에서의 탄성유체윤활 해석

Hydraulic vane pumps are widely used in various hydraulic systems because of its compactness and light weight. It is well known that the vanes and cam ring are separated by very thin liquid films which result in the EHL state. Contrary to the case of cylindrical roller bearings, the inlet and side boundary pressures are much higher than the atmospheric pressure. In this paper, a numerical solution of the EHL of finite line contacts between the cam ring and vane tip with profiled ends is presented. Using a finite difference method with non-uniform grids and the Newton-Raphson method, converged solutions are obtained for moderate load and material parameters. The EHL pressure distribution and film shape are considerably affected by pump delivery pressure and the side boundary condition applied. Both the maximum pressure and the minimum film thickness always occurred near the edge regions. The present results can be used in the design of optimum vane profile in hydraulic vane pump.