Lubrication characteristics of external return spherical hinge pair of axial piston pump or motor under combined action of inclination and offset distance

External return mechanism is a mechanical structure applied to axial piston pumps.To study its lubrication characteristics,the Reynolds equation applied to an external return spherical hinge pair was deduced based on the vector equation of relative-motion velocity of the external return spherical hinge pair under the influence of external swash plate inclination and offset distance.The results show that the total friction,axial leakage flow,and maximum value of the maximum oil-film pressure increase with increasing pump-shaft speed and decrease with increasing offset distance in one working cycle when the external-swash-plate inclination is constant.However,the varying offset distance has little effect on the axial leakage flow.The maximum value of the maximum oil-film pressure decreases with increasing external-swash-plate inclination and the total leakage flow increases with increasing external-swash-plate inclination in one working cycle when the offset distance is constant.It can be seen that the abovementioned parameters are important factors that affect the lubrication characteristics of external return spherical hinge pairs.Therefore,the complex effects of different coupling parameters should be comprehensively considered in the design of the external return mechanism.

Investigation of Valve Plate in Water Hydraulic Axial Piston Motor

This paper has introduced the developments of water hydraulic axial piston equipments. According to the effects of physicochemical properties of water on water hydraulic components, a novel valve plate for water hydraulic axial motor has been put forward, whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely. The material screening experiment of valve plate is done on the test rig. Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied. The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively. It is evident that the appropriate structure should change the wear status between matching pairs and reduces the wear and specific pressure of the matching pairs. The specimen with the new type valve plate is used in a tool system.

Dynamic Analysis of Axial Magnetic Forces for DVD Spindle Motors

The axial magnetic force, induced by the complicated flux linkage distribution from rotor magnet and stator slotted, is constructed by different relative heights and calculated by 3D finite element method (FEM) to analyze the dynamic characteristics for a DVD spindle motor. The axial magnetic force is designed to provide an axial stiffness, and govern the natural frequency of the dynamic performance. According to the simulation results and experimental measurements, the dynamic behaviors are significantly improved with a variation of relative height of rotor magnet and stator slotted on a DVD spindle motor.

Study on Axial Flux Hysteresis Motors Considering Airgap Variation

Axial flux hysteresis motor (AFHM) is self-starting synchronous motor that uses the hysteresis characteristics of magnetic materials. It is known that the magnetic characteristics of hysteresis motor could be easily affected by air gap and structure dimensions variation. Air gap length plays an important role in flux distribution in hysteresis ring and influences the output torque, terminal current, efficiency and even optimal value of other structural parameters of AFHM. Regarding this issue, in this study effect of air gap variation on performance characteristics of an axial flux hysteresis motor and effect of air gap length on hysteresis ring thickness and stator winding turns is investigated. Effect of air gap length on electrical circuit model is perused. Finally, simulation of AFHM in order to extract the output values of motor and sensitivity analysis on air gap variation is done using 3D-Finite Element Model. Hysteresis loop in the shape of an inclined ellipse is adopted. This study can help designers in design approach of such motors.

Design of Axial-Flux Motor for Traction Application

This paper deals with the design of high power – low dimensions axial-flux permanent-magnet motor intended for trac-tion application. First, two motor configurations are analytically designed and compared using finite element calcula-tion. Then, the configuration yielding the best performances is integrated and modelled with the whole traction chain under MATLAB/SIMULINK environment in order to demonstrate the motor operation on a large speed band.

Cogging Torque Reduction in Axial Flux PMSM with Different Permanent Magnet Combination

With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets.

Electric Drive for an In-wheel Fractional-slot Axial Flux Machine

This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed range.The machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and implemented.The goodness of both design and control algorithm is proved by experimental tests.However,such a fractional-slot machine has not only advantages.Rotor losses are very high,and they have to be properly considered during the design process.

A Study on the Composite Type Piezoelectric Motor

This study is to explore a composite type piezoelectric motor. Its main structures include the piezoelectric stator, rotor, the preload adjusting module and shaft. Wherein the piezoelectric stator is made base, the composite type actuating element and stator formed. As the composite type actuating element is set by the axial vibration type actuating element, horizontal bending vibration type actuating element and vertical bending vibration type actuating element formed. The stator is an empty cylinder with a waist and tapered hole. In addition, the rotor is a kind of a hollow cone. It can be through the preload adjusting module to withstand the stator. As the preload adjusting module is set by the limit element, spring, washer and nut formed. While the shaft is a kind of cylinder with screw thread and stopper, it can pass through the piezoelectric stator, rotor and the preload adjusting module, making it a composite type piezoelectric motor. When we provide appropriate driving voltage, frequency, loading and phase angle to the piezoelectric stator, we can let the piezoelectric motor produces rapid rotation. Of course, we can also change through the driving phase angle, to change the direction of rotation of the piezoelectric motor. According to the experimental results, we found that its maximum speed and loading are 480 rpm and 2305 gw under conditions of 180 Vp-p, 35 kHz and 00 driving phase angle. Most importantly, we also found that the composite type piezoelectric motor has a very good conversion efficiency of the driving phase angle.

Developing a 3D-FEM Model for Electromagnetic Analysis of an Axial Flux Permanent Magnet Machine

Recently, many optimal designs for axial flux permanent magnet (AFPM) motors were performed based on finite- element (FE) analysis. Most of the models are based on reduction of 3D problem to 2D problem which is not accurate for design aspects. This paper describes an accurate electromagnetic analysis of a surface mounted, 28 pole AFPM with concentrated stator winding. The AFPM is modeled with three-dimensional finite-element method. This model in-cludes all geometrical and physical characteristics of the machine components. Using this accurate modeling makes it possible to obtain demanded signals for a very high precision analysis. Magnetic flux density, back-EMF, magnetic axial force and cogging torque of the motor are simulated using FLUX-3D V10.3.2. Meanwhile, the model is paramet-ric and can be used for design process and sensitivity analysis.

双调制式轴向永磁齿轮电动机气隙磁场与转矩计算

针对轴向永磁齿轮电动机(Axial Magnetic Gear Motor,AMGM)整体尺寸偏大导致的转矩密度偏低(≤70 kN·m/m^(3))等缺陷,提出了一种双调制式轴向永磁齿轮电动机(Dual-modulation Axial Magnetic Gear Motor,DAMGM)。采用高速侧及低速侧两个调磁环对DAMGM低速转子进行调制,且两个调磁环中的非导磁部分均为永磁体,有效提高了低速转子的输出转矩;另外,与现有AMGM相比,将驱动电动机置于DAMGM高速永磁转子内部,减小了整体轴向尺寸,大幅提高了低速转子的转矩密度(150 kN·m/m^(3))。针对现有3D有限元计算时间长、计算机资源浪费严重等问题,给出一种基于圆柱坐标系的DAMGM三维分析方法。根据调磁环的3种边界条件,建立了调制后DAMGM气隙磁场及电磁转矩的数理模型,不仅计算结果准确(与3D有限元相比,平均计算误差≤5%),而且计算时间短(仅为3D有限元的1/10),便于DAMGM不同参数结构的分析、比较与优化。

定子通风槽钢结构对提高中型高压电机散热性能分析

为降低YJK450-6、400kW中型高压电机的通风散热性能,本文对该电机不同通风槽钢结构进行了散热性能研究。首先,在现有电机的直线标准型通风结构基础上,提出单列缩放型、双列直线型、双列缩放型3种轴-径向混合通风结构形式;在SpaceClaim软件中建立电机3维温度场数值计算模型,根据基本假设和边界条件结合电机内部热量传递公式计算出电机仿真设置参数,并导入Fluent软件进行仿真模拟,其中,计算温度场所用热源通过AnsoftMaxwell平台计算的电机损耗值获取。其次,通过网格无关性和温升试验验证本文建立的电机3维温度场数值计算模型;通过仿真模拟对比分析3种轴-径向混合通风结构与直线标准型结构对电机流场和温度场的影响;采用正交试验法对轴-径向混合通风结构进行参数优化,得到最佳散热结构和参数方案;进一步探究冷却风速对双列缩放型槽钢的电机换热性能的影响;结合定子绕组温升和电机整体的温升均匀性系数,对最佳散热结构和参数方案电机进行散热效果评价。仿真结果表明:本文建立的计算模型是有效的;双列缩放型通风槽钢结构的各项散热性能指标均最好,是最优通风槽钢结构;径向风道高度为6mm且数量为13的双列缩放型通风槽钢结构为最佳散热结构和参数方案;双列缩放型通风槽钢结构两侧的平均对流换热系数随冷却风速增大而增大,且槽钢迎风面的平均对流换热系数明显大于背风面;径向风道高度为6mm且数量为13的双列缩放型通风槽钢结构电机的内/外层绕组温升分布均匀性系数比直线标准型电机分别提高88.13%、20.11%。因此,优化设计通风槽钢结构有利于电机内部空气流动和散热,可实现有效降低电机内部温升的目的。

高效非晶合金电机关键技术研究综述

非晶合金以其优异的低损耗特性在电机领域受到越来越多的关注。对非晶合金电机的研究进展进行梳理,介绍了非晶合金电机相对传统电机的优势,阐述了现阶段非晶合金电机铁心常用的加工工艺以及非晶合金电机的研发应用情况。对非晶合金电机关键技术的研究现状进行总结,包括考虑加工工艺、装配工艺下非晶合金电机铁心损耗与温升的精确计算,径向磁通与轴向磁通非晶合金电机振动噪声的精确计算,非晶合金电机设计优化与前沿应用,并对非晶合金电机未来发展趋势与研究方向进行了展望。

混合转子永磁电机双风道冷却系统设计

混合转子永磁电机具有高功率密度的优势,但也导致电机散热空间和散热能力不足等问题。为此,根据其特有的转子结构提出一种双风道冷却系统,并采用计算流体力学(Computational fluid dynamics,CFD)的方法对电机温度场进行验证。首先,根据电机损耗和尺寸设计一个适合双风道的轴流风扇。其次,对不同进、出风口的结构参数进行仿真,对比和分析仿真结果,选出冷却性能较好的参数组合。最后对单风道和该参数组合下的双风道进行数值模拟,仿真结果表明,使用双风道冷却结构后电机散热能力显著提升。

斜轴式柱塞马达外壳的振动与噪声特性分析

为降低柱塞马达的噪声,提升液压系统的稳定性,针对斜轴式柱塞马达的外壳进行了振动和噪声特性分析。首先对马达的内部激振源和振动传递路径进行分析,然后在ANSYS中对外壳依次进行模态分析、谐响应分析,获得对外壳结构动态性能影响最大的模态频率及工作时结构振动剧烈的区域,最后在半消声实验室对斜轴式柱塞马达进行噪声测试,验证了仿真结果的准确性。研究结论为斜轴式柱塞马达的减振降噪技术提供了新思路。

径轴向聚磁型永磁推进电机优化设计与分析

为了进一步实现永磁电机磁负荷和转矩密度的提升,提出了一种径轴向聚磁型永磁推进电机结构,转子永磁体在Halbach径向聚磁结构基础上进一步结合轴向延伸永磁体,实现了永磁磁场的径轴向聚磁。针对该种新型电机,本文详细研究了其结构特点,利用有限元分析了所提电机结构的电磁性能。首先对比分析了定转子等长结构、定转子不等长(overhang)结构输出性能,并对对称型overhang结构进行了参数化优化,有效提升了电机转矩密度。最后,利用三维有限元模型对比分析了径向overhang和径轴向overhang电机的电磁性能,结果发现径轴向overhang电机空载磁密提升了6%、输出转矩增大了1.3%、转矩脉动减少了0.4%,进一步验证了电机性能的优越性。

A Study on the Linear Piezoelectric Motor of Mode Shape

In this paper, we want to make a new type linear piezoelectric motor by mode shape coating or effective electrode surface coating. The mode shape is derived from the mechanical boundary conditions of the linear piezoelectric motor. We only have access to the first three modes of formas, the effective electrode surface coating basis, as well as with the linear piezoelectric motor of normal shape do comparison. Next, we will inspect their gain or axial velocity through theoretical analysis, simulation and experiment. According to the results of the theoretical analysis, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much larger than the linear piezoelectric motors of normal shape. However, according to the results of simulation and experiments, we have found that the gain or axial velocity of the linear piezoelectric motors of mode shape is much greater than the linear piezoelectric motors of normal shape, which is about 1.2 to 1.4 times. The linear piezoelectric motor of mode shape 3 has the fastest axial velocity, which is about -48 mm/s and 48 mm/s under conditions of 180 Vp-p driving voltage, 21.2 kHz driving frequency (the third vibration modal), 25 gw loading and the position of loading or mass at x = 5 mm & 45 mm respectively. And its axial velocity is about 1.4 times the linear piezoelectric motor of normal shape under the same conditions. Overall, the mode shape coating helps to enhance the gain or axial velocity of the linear piezoelectric motor.

基于四配流轴向柱塞马达的制动能回收方法

针对大惯性回转机构在制动时,动能都以热能的方式损失的问题,提出一种四配流轴向柱塞马达和蓄能器结合的制动能回收方法。不同体积、初始压力的蓄能器对惯性负载的回转制动能的回收和再利用的效果不同,为寻求较合理的蓄能器参数以达到较高的能量回收效果,手动调整仿真参数较为繁琐,提出采用基于多核CPU的快速并行优化方法用于蓄能器参数优化。首先,大惯性负载的驱动机构采用四配流轴向柱塞马达,其能量系统回收模型在Simulation X搭建,进而导出成具有CVODE求解加速的可执行程序,脱离仿真软件平台,在Windows操作系统独立运行;然后,利用导出的可执行程序与VC++进行二次开发,以微粒群算法解决特定工况下蓄能器选型的问题,充分利用多核CPU实现并行优化以提高仿真速度。仿真结果表明,在特定负载下得到优化后的蓄能器的参数,蓄能器回收并释放的能量占惯性动能的24.5%,回收油液全部得到释放。采用基于多核CPU的并行优化方法,仿真效率提高了10倍以上,该方法对系列化液压产品的快速开发具有一定的借鉴价值。

定子结构优化对盘式电机齿槽转矩的影响分析

齿槽转矩会恶化电机性能,为削弱盘式永磁电机齿槽转矩,文章提出了定子偏移和不等定子齿靴两种结构优化方法。首先通过能量法与傅里叶分解推导出轴向电机齿槽转矩公式,进行定子槽口宽度优化得到原模型的最小齿槽转矩;然后用公式推导计算与有限元分析,得到定子偏移结构的偏移角度;最后通过理论分析和仿真计算得到基于最小齿槽转矩的不等定子齿靴扩张宽度比,不等定子齿靴结构可使定子上下两侧的齿槽转矩相互抵消。对比结果表明,不等定子齿靴结构对齿槽转矩削弱效果最好,当扩张宽度比取1.2时,齿槽转矩降低71%。

聚磁式转子轴向磁齿轮复合电机的有限元分析

在系统介绍轴向磁齿轮复合电机基本工作原理的基础上,提出了一种具有聚磁式转子的轴向磁齿轮复合电机。采用有限元分析方法对复合电机的电磁性能进行了三维数值仿真分析,验证了电机结构的合理性,并详细分析了聚磁式转子结构参数对电机输出转矩与轴向磁拉力的影响,得出转子参数对转子两侧圆周和轴向磁拉力的影响相似,为后续的试验研究提供了理论参考。

周向散热的非晶合金轴向磁通电机温度场研究

合适的冷却结构能够保证电机安全运行的同时,也能够简化电机设计。为有效控制无轭定子结构的轴向磁通电机的整体温升,提升其散热能力,基于非晶合金电机低损耗的特点,提出了一种在机壳上集成周向式散热叶片的外转子散热结构。通过流固耦合的方法,对该结构下的电机进行了温度场的分析,验证了该方案的可行性。对一台额定功率为20 kW的轴向磁通电机进行温升实验,实验结果证明了该散热结构的有效性。