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多泵多电机驱动系统输出速度的理论分析温德生中国，秦皇岛，燕山大学机械工程学院通信作者（电子邮箱：, wendesheng ）(收稿日期：2010年6月13日 接收日期：2011年1月18日 在线出版日期：2011年2月21日)摘要：本文提出的是一个多泵多马达液压系统的理论，它基于对流行的液压传动和双定子电机（泵）的优缺点进行分析。以单动固定位移多泵多马达驱动系统为例，对各种连接的新型液压传动的输出速度进行了理论分析。本文的研究工作为多泵多马达驱动系统及系统的原理图设计的研究奠定了理论基础。关键词：多泵多马达驱动系统，连接方式，扭矩，转动速度，差动电动机1. 引言随着液压技术的广泛应用和液压元件的快速发展，对流量和压力液压泵电机，转矩和转速等噪声，效率，寿命，耐冲击，具体电源，控制方法及其他方面产生更高的要求。为了提高液压传动部件而应用相关技术和新材料的新的密封和润滑方法引起了学者的关注。而其他的研究人员正在试图改变部分摩擦材料来改善性能和提高电机的寿命。所有这些研究都是基于现有的工作原理和液压泵及马达。然而，很少人对液压元件1-4的工作原理进行了研究。一般来说，常用的液压传动系统由单泵和一个旋转在一个壳的相应的单电机定子5,6组成。虽然被广泛使用，在实际应用中这类的传输系统仍有一些缺点：1) 当液压系统中需要有若干不同的固定流量需要多个固定位移泵。2) 当液压系统两个或两个以上的变流量是必要的，两个以上的变量位移泵需要完成的工作。3) 当液压系统有两个或更多的不同压力时，一个泵作为动力不能压缩。因此，释放阀必须使用。注意减压阀浪费能量，因为这种能量在该阀不产生功率并且损失的功率在液压系统中转化成热量。这也是油温升高的直接原因，这将导致泄漏，磨损和低效率，也可能降低液压系统的使用寿命。它仅仅被设计用于提供使用一个泵的不同压力的液压系统。4) 当多个驱动器需要在不同的压力和流量下实现同步运动，一个传统的液压泵不能满足要求。当气缸直径气缸数不同，它要实现同步运动更加困难。5) 当一个电机需要输出多个固定转矩和恒定转速，但现有固定位移电机不能满足需要。总之，在实际使用中要解决上述液压传动的问题是不容易的。发展一些新的类型的液压元件和传输模式是实际应用中的解决方案。双定子电机的试验成功为多泵多马达液压系统的进一步研究打下了良好的基础。在这篇文章中，对多泵多电机传动系统和新型的液压元件图形符号进行定义。以一个单作用固定位移多泵多马达作为一个例子简要回顾了双定子泵（电机）原理后，对各种连接输出转速进行了详细的分析。基于现有的结构和液压元件的工作原理对多泵多马达液压系统研究是一个重要和具有挑战性的问题。出于这个原因，我们试图创结构和组件的工作原理领域，进行了一系列创新，可以较好地解决上述问题。2. 多泵多马达的定义有国家专利的等宽曲线双定子泵（马达）在中国国家自然科学基金的支持下成功的进行了测试。当它被用来作为泵，可在壳中形成几个泵。它不同于现有的几个泵在一个壳的液压元件，但泵及定子和转子的数量都是一样的。这种泵，无论有多少泵，一个定子（或转子）对应于两个转子（或两定子）是必要的。它具有体积小，重量轻，结构简单，在特定的电源效率高，可以输出不同流量的优点。这种新型泵称作一壳多泵。同样的，当它被用来作为电机，我们可以在一壳中得到确定数量的电机并且输入不同的流速。多速电机或差绕电机也可以获得。同样，这种电机一壳多机。由双定子多泵多马达组成的新型液压传动定义为多泵多电机传动。有几种不同的组合，如单电机单泵，单泵多马达，单机多电机多泵多泵。在多泵多马达系统，一些典型电路，如单动和双动气缸同步电路，单动和双动气缸带多级调速电路，可通过液压缸和多泵组合得到的。3. 结构及工作原理多泵多电机传动系统的基础是多泵多马达，它是基于双定子泵和电机的研究。目前，对液压泵和马达的基本结构特征是在一个壳中一个转子对应一个定子。这种新型电机/泵不同于现有的泵和马达，它有两个定子对应一个转子和一定数量的输入和输出端口，这依赖于动作次数。这种新型的结构被称为双定子，可满足泵或马达的实际需要。例如，宽度相等的曲线双定子泵（马达）（如图1所示）提出了包括内定子（1），外定子（3），转子（2），内辊（6），连杆（7）和一个外辊（8）。壳体上的两对入口和出口端口用于抽吸和输送作用。他内、外定子是相等的，两者之间的距离条纹是相似曲线。为了形成一个可变容积，转子和定子中心之间的距离是确定的。在外泵的控制量是由外定子，外辊（S），转子，连接杆和两个侧板组成。入口和出口段由位于两个侧板的阀板来达到控制泵的功能。同样的，内泵控制量由内定子，内辊（S），连杆，转子和两个侧板组成。因此，内部和外部的泵在泵壳。与具有相同作用时间和容积泵相比，有一个单作用泵或双定子泵。因此，位移增大，比功率增加。结果，滚轮的滚动摩擦，滚轮和定子之间可以减少摩擦损失。此外，如果我们改变内部定子和外定子的形状，然后双动，三动甚至多动双定子泵可获得。有双动双定子多泵四分泵。三代双定子多泵分别有一壳六泵，包括相等的位移的三内泵和三外泵。六电机形成，当被用于电机。所有这些子泵可以单独或结合，根据实际需要。连接杆对辊可以设计为矩形滑块，单辊，同心圆叶，如7,8所示。三代双定子多泵的结构（多电机）与辊，如图2所示。其基本结构包括外定子1，转子3，内定子4和滚子2。 图1 (a)单动双定子结构部分；(b) 单动双定子原型；(c) 测试系统；(d) 连接单元1内部定子；2转子；3外定子；4外部变量泵；5内泵变流量；6内辊；7连杆；8外辊。图2三代双定子多泵工作原理4. 图形符号为了清楚地描述这一新兴产业的创新，它需要设计新型液压元件图形符号。参照图形符号的现有规则，五个规则建立如下：规则1：有几个泵/汽车存在一个壳，使用相同定子和转子并且同轴驱动，我们采用图形符号。规则2：一个圆圈代表外泵/马达。两个同心圆圈代表内泵/马达。规则3：位于半圈侧三角形数目的子电动机或分泵的数量相同。规则4：在一个圆圈的双向三角形代表可逆多泵多马达。规则5：对多泵变位移的表达方式（多机）和以前是一样的。例如，单作用可逆可变位移多泵如图3所示，(a)和(b)说明了一个双作用可逆固定位移多电机。图3多泵多马达一些图形符号5. 多泵供油方式不同的输出和输入的流量可以通过分别改变多泵或多电机连接方式获得。在这里，不同的输出流量用于电机。所有这些子泵可以根据实际需要单独使用或结合。连接杆对辊可以设计为矩形滑块，单辊，同心圆叶等。三代双定子多带辊泵的结构（多电机），如图2所示。其基本结构包括外定子1，转子3，用来作为能源资源的多泵内定子被详细研究。当它被用在一个液压系统，几种不同的固定流量可以由一个多泵通过改变接线方式本身来实现。不同压力系统，当一个多泵作为能源，减压阀是没有必要的。有三种不同的连接方式为单动多电机；如图4所示。图4单作用可逆固定位移多泵连接方式设和分别是内部外部泵的位移，是电动机的转速。因此，输出流量有三个不同的值。对内泵单独工作的连接方式如图4(a)所示。在这种情况下，输出流量表示为： (1)图4(b)显示在工作外泵的连接方式。然后外泵的流量可以表示为： (2),其中：是常数，其取决于内部和外部的泵设计位移。该泵内、外泵工作在同一时间，连接方式如图4(c)所示，总的输出流量 (3)公式(3)表明总流量和内泵或外泵流量之间的关系。根据双定子多泵的结构，导出。综上所述，单作用多级泵可输出三个不同的流率值并且没有复杂的变量机构和节流阀。每个子泵在同一时间不同的工作压力下可以独立工作。此外，通过内在泵和泵的输出流量外设置一个比例关系，通过调节转子偏心变位移函数实现。6. 多电机连接方式 当作为一个电机，确定量的不同输出转速可以在相同的输入流下得到。为了便于解释，我们假设在不同连接的输入流量为相同，内部和外部泵分别为和。单动多电机的四种连接方式如图5所示。图 5单动双定子电机连接方式让和分别是内电机和外电机的输出转速。图5(a)显示，在外电机空转时，只有内部电机工作。输出转速可以表示如下： (4)图4(b)显示的操作模式，外电机单独运作和输出转速可表示如下： (5)类似于单作用多级泵，我们得到： 其中：C是常数并且在位移设计时是独立的。图5(c)表明，内、外电机同时工作，输入流具有相同的流动方向。假设总流量是在这种情况下，输出的转速表示为： (6)由公式(4)-(6)得到： (7)图5(d)说明了单作用多电机差动连接，类似于微分筒连接。在这种情况下，输出转速： (8)通过以上分析，单和双定子固定位移的多电机可以在相同的输入流下输出四种不同转速，无需复杂的机制。类似地，它可设计为双作用，三代甚至多作用的双定子多电机。7. 多泵多马达的组合方式分别获得多泵多马达的各种连接方式后，结合多泵多马达以及传输电路的实现，如多电机单泵，单电机多泵，单作用多泵多电机，双作用多泵和多电机和多泵多马达系统。如此多的连接方式，可以多电机之间实现，我们将以单动多泵多马达为例。为了简化计算，多台电机的输出转速，结果如表1所示，参数的定义不改变。在表1中，第一个垂直列代表连接单动多泵，第一水平列显示连接单动多电机。例如，代表输出转速的液压油由单独的内泵提供。表1单动双定子多单输出转速连接方式内部电机外部电机内部和外部电机差动电机内泵外泵内外泵例如，连接方式的内、外电机同时工作时，液压油是由内、外泵同时供给，如图6所示。在这方面，总的输入流，多电机的位移，输出转速，同样的，其他的结果可以以同样的方式获得。总之，通过这种单动双定子固定位移多泵多马达的组合，十二种不同的输出转速可获得无需节流阀或任何其他帮助。图6单动双定子多泵多马达连接模式8. 结论和未来的工作从以上分析可以得出结论1. 多泵多电机传动，具有独特的性能和优势的一种新的传输模式。2. 该新型液压元件的基本结构是有一对应两个定子的转子。因此，只在一个壳中形成两个电机或泵。本文的研究工作提供了多机液压传动的研究多泵的理论基础，并增加了一个新的液压元件系列。3. 几种不同的流量和旋转速度可以分别通过这样一种固定输送泵和电机提供。不需要改变机构或其他帮助。此外，还有一种比例关系的输出流量和转速。4. 差绕电机的功能都实现了，并且扩大应用范围，提高多电机的适应性。作为内、外定子之间的距离是相等的，没有返回弹簧或并且这样的机制是必需的。5. 液压执行器同步工作可以很容易地实现，当他们被多泵多电机传动并且不需要节流阀或可变机构。还可以减少能量损失。总之，本文提出了一种新的工业设计，能够产生大量的液压系统设计的概念，可以自动指定的操作要求。在未来，双定子的多泵多马达需要更多的实验和仿真进行完善的理论分析。本论文由国家自然科学基金资助（基金号：50975246）参考文献：1 Kim G W, Wang K W. 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Beijing: Aviation Industry Press, 2009. 375384Theoretical analysis of output speed of multi-pumpand multi-motor driving systemWEN DeSheng*College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, ChinaReceived June 13, 2010; accepted January 18, 2011; published online February 21, 2011A theory for multi-pump and multi-motor hydraulic systems is presented in this paper based on the analysis of the advantages and disadvantages of the popular hydraulic transmission and the double-stator motor (pump). By taking the single-acting fixed displacement multi-pump and multi-motor driving system as an example, the output speeds in a variety of connections of this novel hydraulic transmission are analyzed theoretically. This research work lays a theoretical foundation for the study of the multi-pump and multi-motor driving system and for the design of the system principle diagram.multi-pump and multi-motor driving system, way of connection, torque, turning speed, differential motor1 IntroductionWith the wide applications of hydraulic technology and the rapid development of hydraulic components, higher requirements have come into being for flow and pressure of hydraulic pumps, torque and speed of motors as well as noise, efficiency, service life, impact resistance, specific power, control method and others. New sealing and lubrication methods for applying relevant technologies and advanced materials have attracted much attention of some scholars for improving the hydraulic transmission and components, while other researchers are trying to change part of friction material to improve the performances and increase the life span of the motors. All of these researches are based on the existing operating principles of hydraulic pumps and motors. However, few studies are carried out on the operating principle of hydraulic components 14. Generally, the commonly used hydraulic transmission systems consist of single pumps and single motors with one rotator corresponding to one stator in one shell 5, 6. Although having been widely used, there are still some disadvantages for this kind of transmission systems in practical applications:1) Several fixed displacement pumps are needed when there is a requirement for a number of different fixed flow rates in a hydraulic system at the same time.2) When two or more variable flow rates are necessary in a hydraulic system, more than two variable displacement pumps are required to accomplish the work.3) When there are two or even more different pressures in one hydraulic system, one pump as energy resource can not work for compression. Thus, release valve(s) must be used. Note that the compression release valve is a waste of energy, because the energy in this valve produces no power and the lost power is transformed into heat in the hydraulic system. It is also a direct cause to higher temperature of oil, which will lead to leak, abrasion and lower efficiency and may also reduce the service life of the hydraulic system. It is just designed to supply different pressure hydraulic system using one pump.4) When more than one actuator need to achieve a synchronized movement in different pressures and flows, one conventional hydraulic pump can not satisfy the requirement. It is more difficult to realize synchronized movement with different cylinder diameters when the number of cylinders is odd. 5) When one motor is required to output multiple fixed torques and constant rotating speeds, the existing fixed displacement motors can not meet the needs yet.In summary, it is not easy to solve the above mentioned problems for hydraulic transmission in practical use. Developing some new types of hydraulic components and transmission modes are one solution to practical needs. The successful test of double-stator motor (pump) can lay a good foundation for further studies on multi-pump and multi- motor hydraulic systems. A multi-pump and multi-motor transmission system and the graphic symbols of these novel hydraulic components are defined in this paper. By taking a single-acting fixed displacement multi-pumps and multimotors as an example, the output rotational speeds in various connections are analyzed in detail, after briefly reviewing the principles of the double-stator pump (motor).It is a significant and challenging issue to study the theory of multi-pump and multi-motor hydraulic system based on the existing structure and operating principles of hydraulic components. For this reason, we try to innovate in the field of structure and operating principles of components and develop a series of novel ones, which can better solve the above problems.2 Definition of multi-pumps and multi-motorsThe equal width and curvilinear double-stators pump (motor), which has a China patent, was successfully tested under the support of the National Nature Science Foundation of China.When it is used as the pump, several pumps can be formed in one shell. It is different from the existing hydraulic components with several pumps in one shell and the number of pumps, stators and rotors are the same. For this kind of pump, no matter how many pumps there are, just one stator (or one rotor) corresponding to two rotors (or two stators) is needed. It has the advantages of small size, light weight, simple structure, high efficiency in specific power and can output several different flow rates. This type of novel pump is called multi-pumps-in-one-shell. Similarly, when it is used as the motor, we can obtain a certain number of motors in one shell and input different flow rates. The multi-speed motor or differential motor can also be acquired. Likewise, this kind of motor is called multi- motors-in-one-shell. The novel hydraulic transmission, which is composed of double-stators, multi-pumps and multi-motors, is defined as the multi-pump and multi-motor transmission. There are several different combinations, such as single-pump with singlemotor, single-pump with multi-motors, multi-pumps with single-motor and multi-pumps with multi-motors. In multipump and multi-motor systems, some typical circuits, such as synchronization circuit of single-acting and double-acting cylinder, single-acting and double-acting cylinder with multistage speed-regulating circuits, can be obtained by the combination of the hydraulic cylinder and the multi-pumps.3 Structure and operating principlesThe foundation of multi-pump and multi-motor transmission system is multi-pumps and multi-motors, which is based on the study of double-stator pump and motor. Currently, the basic structure feature of the hydraulic pumps and motors is that one rotator corresponds to one stator in one shell. This type of novel motor/pump is different from the current pumps and motors in that it has two stators corresponding to one rotor and a certain number of input and output ports which are dependent on action times. This new type of structure is called double-stators and can be used as pump or motor for practical needs. For example, the equal width and curvilinear double- stator pump (motor) (see Figure 1) proposed in this paper includes an inner stator (1), an outer stator (3), a rotor (2), an inner roller (6), a connecting-bar (7) and an outer roller (8). Two pairs of inlet and outlet ports on the shell are used for suction and delivery action. The distance between the inner and the outer stator is equal and both of their fringes are resembled curves. In order to form a variable volume there is a certain distance between the centers of rotor and stator. The control volume of the outer pump is formed by the outer stator, the outer roller(s), the rotor, the connecting-bar and two side plates. The inlet and outlet segments are controlled by the valve plate which is located on the two side plates to achieve the functions of a pump. Likewise, the control volume of the inner pump is composed of the inner stator, the inner roller(s), the connecting-bar, the rotor and the two side plates. Thus, the inner and outer pumps are in one pump-shell. Compared with the pump with the same action times and volume, there is one pump or more for single-acting double-stator pump. Hence, the displacement is enlarged and the specific power is increased. As a result, the rollers, the rolling frictions among rollers and stators can reduce the damage due to friction. Figure 1 (a) Structure section of the single-acting double-stator; (b) prototype of single-acting double-stator; (c) testing system; (d) connection unit. 1, Inner stator; 2, rotor; 3, outer stator; 4, variable volume of outer pump; 5, variable volume of inner pump; 6, inner roller; 7,connecting-bar; 8, outer roller.Figure 2 Operating principle of triple-acting double-stator multi-pumps.Furthermore, if we change the shape of the inner stator and the outer stator, then the double-acting, the triple-acting and even the multiple-acting double-stator pump can be acquired. There are four sub-pumps for double-acing double stator multi-pumps. For triple-acting double-stator multipumps, there are six pumps in one shell, which includes three inner pumps and three outer pumps with equal displacement, respectively. Six motors are formed when it is used as motor. All of these sub-pumps can work alone or be combined, according to the actual requirement. Double roller with a connecting-bar can be designed as rectangle sliders, single-roller, concentric circle vane, etc. 7, 8. The structure of triple-acting double-stator multi-pumps (multi-motors) with rollers is shown in Figure 2. Its basic structure includes an outer stator 1, a rotor 3, an inner stator 4 and roller 2.4 Graphic symbolsIn order to clearly describe this new industry innovation, it is needed to design the graphic symbols of these novel hydraulic components. Considering the existing rules of graphic symbol, five rules are established as follows: Rule 1: As several pumps/motors exist in one shell, using the same stators and rotors, and driven by the same axis, we adopt the coaxial graphic symbol. Rule 2: One circle stands for the outer pump/motor. Two concentric circles represent the inner pump/motor.Rule 3: The number of triangles located by the side of semi-circle is the same as the number of sub-motors or sub-pumps.Rule 4: The two-way triangle in a circle represents the reversible multi-pumps or multi-motors.Rule 5: The expression way of variable displacement of multi-pump (multi-motor) is the same as before.For example, the single-acting reversible variable displacement multi-pumps is shown in Figures 3(a) and (b) illuminates a double-acting reversible fixed displacement multi-motors.Figure 3 Some graphic symbols of multi-pumps and multi-motorsFigure 4 Connection modes of single-acting reversible fixed displacement multi-pumps5 The ways of oil supply of multi-pumpsDifferent output and input flow rates can be acquired by changing the connection mode of the multi-pumps or the multi-motors, respectively. Here, different output flow rates of multi-pumps which are used as energy resource are studied in detail. Several different fixed flow rates can be supplied by one multi-pump by changing the connection ways of itself when it is used in one hydraulic system. For different pressure systems, the pressure reducing valve is not necessary when one multi-pump is used as energy resource. There are three different connection ways for single- acting multi-motor; see Figure 4. Let and be the displacements of the inner and outer pump, respectively, and be the rotating speed of the electro-motor. Thus, the output flow has three different values.The connection mode of the inner pump working alone is shown in Figure 4(a). Under this condition, the output flow rate is expressed