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Electric drive axle descriptionAbstract: An electric drive axle, which is located between and powers the left and right drive wheels of an automotive vehicle, includes an electric motor and left and right torque couplings. Torque developed by the motor transfers through the torque couplings to axle shafts which are connected to the drive wheels. Each torque coupling includes a magnetic particle clutch and a planetary set organized such that the current flowing through the electromagnet of the clutch controls the torque delivered through the coupler. The magnetic particle clutches also accommodate slippage so that the drive wheels may rotate at different angular velocities.BACKGROUND OF THE INVENTION This invention relates in general to automotive vehicles and, more particularly, to an electically-powered drive axle for an automotive vehicle. The typical automobile derives all the power required to propel it from an internal combustion engine which is coupled to left and right drive wheels through a transmission and differential. Indeed, the differential divides the torque produced by the engine evenly between the drive wheels to which it is coupled. Recently several automotive manufacturers have demonstrated an interest in automobiles that in one way or another utilize electric motors to propel the vehicles. But these vehicles still rely on differentials of conventional construction to divide torque between the left and right drive wheels and to accommodate variations in speed between the drive wheels, such as when the vehicle negotiates a turn. However, an equal division of torque between the drive wheels on each side of a differential is not always desirable. For example, if the traction available to one of the drive wheels is diminished, most of the torque should flow to the other drive wheel. Also in turns, handling improves if most of the torque flows to the drive wheel on the outside of the turn. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a schematic view of an automotive vehicle provided with an electric drive axle constructed in accordance with an embodying the present invention;FIG. 2 is an end view of the vehicle cut away to show the electric drive axle; FIG. 3 is a sectional view of the drive axle; FIG. 4 is an enlarged sectional of one of the torque couplers in the drive axle; FIG. 5 is an end view of a vehicle provided with a modified electric drive axle; FIG. 6 is a sectional view of the modified electric drive axle. DETAIL DESCRIPTION OF THE INVENTION Referring now to the drawings, an automotive vehicle A (FIG. 1) has a left and right drive wheels 2 and 4, respectively, that are powered through an electric drive axle B. To this end, the vehicle A has a source 6 of electrical energy, which could be a generator powered by an internal combustion engine or a bank of batteries or even fuel cells. In any event, the energy source 6 and the drive axle B are mounted on a supporting structure 8, which could be a frame or a unified body, and the supporting structure 8 is in turn supported in part by the wheels 2 and 4. The drive axle B is coupled to the wheels 2 and 4 through left and right axle shafts 10 and 12. It is organized about an axis X and includes (FIG. 2) a housing 20, an electric motor 22, and left and right torque bias couplings 24 and 26, respectively. The motor 18 and couplings 24 and 26 are located within the housing 20. The motor 18, which is of the radial flux construction, includes (FIG. 3) a stator 30 which is mounted in the housing 20 in a fixed position around the axis X. It also includes a rotor 32 which is located within the stator 30 where it revolves about the axis X. The rotor 32 includes a motor shaft 34 which at its ends is supported in the housing 20 on antifriction bearing 36. The housing 20 also encloses the two torque couplings 24 and 26, each of which includes a drive hub 40, a magnetic particle clutch 42, a planetary gear set 44, and a drive flange 46. They too are organized along the axis X. The two drive hubs 40 are connected to the motor shaft 34 of the rotor 32 through splines or other devices which enable them to rotate with the shaft 34 and transfer torque from the rotor 32 to their respective torque couplings 24 and 26. Indeed, the two drive hubs 40 rotate in the bearings 36 and support the shaft 34 and likewise the rotor 32 on the bearings 36. The drive flanges 46 are for the most part located externally of the housing 20 and serve to couple their respective torque couplings 24 and 26 to the axle shafts 10 and 12. The drive hubs 40 function as torque input members, whereas the drive flanges 46 serve as torque output members. The clutch 42 for each torque coupling 24 and 26 includes (FIG. 4) an electromagnet 50 and an armature 52. Both are annular in configuration and are organized about the axis X. The armature 52 resides within the electromagnetic 50, with the two being separated by antifriction bearings to the maintain a uniform annular gap g between them. The gap g contains magnetic particles. In the absence of a magnetic field at the gap g, the magnet 50 and armature 52 can rotate, essentially freely with respect to each other. However, when an electrical current is directed through the magnet 52, torque applied to the magnet 52 will transfer to the armature 54. Some slippage between the two may and in most instances will occur. The magnet 50 around its periphery carries slip rings 56 which are wiped by brushes 58 fitted to the housing 20. The brushes 58 in turn are connected to a source of electrical energy, the potential of which may be varied to vary the current in the electromagnet 52 and the strength of the magnetic field it produces. This controls the torque transferred by the clutch 42. The electromagnet 50 of the clutch 42 is secured firmly to the flange of the drive hub 36 at that end of the motor shaft 34 nearest the coupling 24 or 26 of which the clutch 42 is a component. Thus, the electromagnet 52 rotates with the rotor 32 of the electric motor 32. Should the electromagnet 52 be energized, torque applied to the electromagnet 52 will transfer to the armature 54. The planetary set 44 for each torque coupling 24 and 26 includes (FIG. 4) a sun gear 64, a ring gear 66, and planet gears 68 located between and engaged with the sun and ring gears 64 and 66. In addition, it has a carrier 70 which establishes the axes about which the planet gears 68 rotate. The sun gear 64 lies along the axis X, its axis coinciding with the axis X. It is provided with a stub shaft 72 which projects into the armature 56 of the clutch 42, to which it is coupled through mating splines. The ring gear 66 is attached to the electromagnet 54 of the clutch 42 and to the flange on the drive hub 40 at the end of the motor shaft 34, so that the hub 36, the electromagnet 54, and the ring gear 66 rotate in unison about the axis X and at the same angular velocity. The carrier 70 has pins 74 which project into the planet gears 68, so that the planet gears 68, when they rotate, revolve about the pins 74. The pins 74 thus establish the axes of rotation for the planet gears 68. In addition, the carrier 70 has a spindle 76 which projects through the end of the housing 20 and there is fitted with the drive flange 46. The left axle shaft 10 is connected through a universal joint to the drive flange 46 for the left torque coupling 24, whereas the right axle shaft 12 is connected through another universal joint to the drive flange 46 of the right torque coupling 26. The motor 22 drives the two axle shafts 10 and 12 through their respective torque couplings 24 and 26. The magnetic particle clutches 24 and 26 control the distribution of torque to the two axle shafts 10 and 12. In the operation of the drive axle A, the electrical energy source 6 produces an electrical current which powers the motor 22, causing the rotor 32 and motor shaft 34 of the motor 22 to rotate about the axis X. The motor shaft 34 delivers the torque to the two torque couplings 24 and 26. In each torque coupling 24 and 26, torque from the motor 22 is applied through the hub 40 at that coupling 24 or 26 to the electromagnet 50 of the clutch 42 and to the ring gear 66 of the planetary set 44 simultaneously. Here the torque splits. Some of it passes from the ring gear 66 through the planetary gears 68 to the carrier 70 and thence to the drive flange 46 through the spindle 76. The remainder of the torque, assuming that the electromagnet 50 of the clutch 42 is energized, passes through the gap g to the armature 52 of the clutch 42. The armature 52 rotates and transfers the component of the torque passing through the clutch 42 to the sun gear 64 of the planetary set 44, inasmuch as the armature 52 and sun gear 64 are coupled through the stub shaft 72 of the latter. The sun gear 64 transfers the torque to the planet gears 68 where it combines with the torque transferred from the ring gear 66, so that the carrier 70 and the drive flange 78 see essentially the full torque applied at the hub 40. In other words, the torque flows through each torque coupling 24 and 26 in two paths-a mechanical path, including the ring gear 68, planet gears 68 and carrier 70, and a clutch path, including the electromagnet 50 and armature 52 of the clutch 42, and the sun gear 64, planet gears 68 and carrier 70, of the planetary set 44. Most of the torque transfers through the mechanical path, with the apportionment between the two paths depending on the gear ratio U between ring gear 66 and the sun gear 64. The higher the ratio, the less the amount of torque transferred through the clutch path. The relationship between the torque in the two paths may be expressed with a plot on Cartesian coordinates (FIG. 5). The arrangement is such that a small change in torque transferred through the clutch 42 results in a much greater change in torque transmitted through the coupling 24 or 26 of which the clutch 42 is a component, and the torque transmitted through the clutch 42 is dependent on the magnitude of the current passing through the electromagnet 50 of the clutch 42. The torque varies almost linearly with the current passing through the electromagnet 50. By controlling the current in the clutches 42 of the two torque couplings 24 and 26, the torque can be divided between the two drive wheels 2 and 4 to best accommodate the driving conditions under which the vehicle A operates. For example, if the vehicle A negotiates a left turn, particularly at higher speeds, more torque should be delivered the right drive wheel 2 than to the left drive wheel 4. The clutches 42 in the two torque couplings 24 and 26 are adjusted accordingly. To this end the vehicle A may be provided with accelerometers for determining lateral and longitudinal accelerations and yaw, and hence the severity of turns negotiated, as well as speed sensors for determining the velocities of the two axle shafts 10 and 12, preferably from the antilock braking system for the wheels 2 and 4. More sensors may determine the position of the steering wheel and the temperatures of the clutches 42 and of the wheel service brakes. These sensors produce signals which may be fed to a microprocessor in the vehicle, which microprocessor would determine the best apportionment of torque between the two driving wheels 2 and 4 and control the current in the clutches 42 of the two torque couplings 10 and 12 accordingly. A modified electric drive axle C (FIGS. 6 & 7) likewise distributes torque between the left and right drive wheels 2 and 4, apportioning it best to respond to the conditions under which the vehicle A operates. It includes (FIG. 7) an axial flux motor 84, a housing 86 in which the two torque couplings 24 and 26 are enclosed, and a right angle drive 88 located within the housing 86 between the motor 84 and the hubs 40 of the torque couplings 24 and 26. The motor 84 includes a stator 92 and a rotor 94, as well as a motor shaft 96 in which the rotor 94 is mounted. The shaft 96 rotates about an axis Y oriented at a right angle to the axis X. The right angle drive 88 includes a pinion shaft 100 which rotates in the housing 86 about the axis X on antifriction bearings 102. One end of the shaft 100 is connected to the motor shaft 94, while the other end has a beveled pinion 104 on it. In addition, the right angle drive 88 has a connecting shaft 106 which extends between the two hubs 40 and rotates about the axis X. Its ends are fitted to the two drive hubs 40 with mating splines, and the hubs 40 rotate in the housing 86 on bearings 36. The motor 84, when energized, applies torque to and rotates the pinion shaft 100. The pinion 104 at the end of the shaft 100 rotates the spur gear 108 which in turn rotates the connecting shaft 106 and the hubs 40 at the end of it. The hubs 40 deliver the torque to the torque couplings 24 and 26 which function as they do in the drive axle A. Other so-called hook ups are possible for the two torque couplings 24 and 26-one, for example, in which the armature 52 of the clutch 42 may be connected to the drive hub 40. Also the positions of the clutch 42 and 44 in each of the torque couplings 24 and 26 may be reversed, with the clutch 42 being connected to the drive flange 46.TABLE-US-00001 ELECTRIC DRIVE AXLE A automotive vehicle B electric drive axle C electric drive axle X axis 2 drive wheel 4 drive wheel 6 energy source 8 supporting structure 10 left axle shaft 12 right axle shaft 20 housing 22 motor 24 left torque coupling 26 right torque coupling 30 stator 32 rotor 34 shaft 36 bearings 40 drive hub 42 magnetic clutch 44 planetary set 46 drive flange 50 electromagnet 52 armature 54 bearings 56 slip rings 58 brushes 62 64 sun gear 66 ring gear 68 planet gears 70 carrier 72 stub shaft 74 pins 76 spindle 84 motor 86 housing 88 right angle drive 90 92 stator 94 rotor 96 motor shaft 100 pinion shaft 102 bearings 104 pinion 106 connecting shaft 108 spur gear 电力驱动桥说明书摘要：电动驱动桥一般是安装在车辆的左右驱动轮之间，包括一个电机和左右联轴器。扭矩通过联轴器传到与驱动轮相连的半轴。每个联轴器包括一个磁粉离合器和一个行星组，所以通过调节离合器中的电磁体的电流就能控制经过联轴器传递的扭矩大小。磁粉离合器还能允许滑移，因此驱动轮能得到不同的角速度。发明背景这项发明一般和汽车，尤其是电驱动汽车有联系。典型的汽车输出所需要的能量是从内燃机的做功通过差速器分至左右驱动轮。事实上，差速器把发动机的力矩平均分给了驱动轮，这对力矩是共轭的。最近几次有汽车制造商对利用电机推进车辆感兴趣。但是这些车辆的差速的实现仍然靠传统的差速器将转矩分至左右驱动轮，且能适应驱动轮的速度变化范围小，例如，当车辆转弯时。然而，能把扭矩平均分给驱动轮的差速器并不是一直我们所需要的产品。举个例子，如果一个驱动轮的牵引扭矩降低，那么大部分的扭矩应该流向另一个驱动轮。还有在转弯时，如果大部分的扭矩流向外侧的驱动轮，那么应做改善处理。简要介绍几个图纸的意见图1是从一个原理的角度来展示电动汽车电驱动桥的发明；图2是从车辆尾部的一个剖切面来展示电驱动桥；图3表示的是驱动桥的分解图；图4是一个耦合器在驱动桥上的放大截面图；图5是改进的车辆驱动桥的的最终观点；图6是修改后的电驱动桥的局部观点。详细说明现在要提到一些些图纸，一辆汽车A（图1）有左右驱动轮2和4，分别通过电驱动桥B传递动力。为此，车辆A有一个电源装置6，可以使用内燃机或一组蓄电池甚至燃料电池给电机供电。在任何情况下，电源装置6和驱动桥B是被支承在支护结构8上的，支护结构可以是一个框架或一个阀体，支护结构8是轮流支护在轮子2和4之间。驱动桥B通过左、右半轴10和12联接到车轮2和4。他的结构包括一根轴X和一个桥壳20，左右转矩分别被传递至联轴器24和26。电机18和联轴器24和26被安装在桥壳20上。电机18的径向结构包括（图3）一个定子30，它是安装在桥壳20的一个轴向固定位置。它也包括了在定子30里面围绕轴X旋转的转子32。转子32包括一个末端固定在位于桥壳20里滚动轴承36上的电机轴34。桥壳20也拥有两个扭矩联轴器24和26，它们每一个都包括一个驱动鼓40，一个磁粉离合器42，一组行星齿轮44，一个驱动器法兰46。它们也沿着轴X分布。这两个驱动鼓40通过花键或其他装置联接到转子32上的电机轴34上，使他们与电机轴34共同旋转并将扭矩从转子32传送到联轴器24和26。而且，这两个驱动鼓40也在轴承36上旋转，并且轴承36支承着电机轴34，同也支承着转子32。驱动法兰46大多数是位于桥壳20的外部，从而将力矩作用于联轴器24和26并分别作用到半轴10和12。驱动鼓40的功能是作为力矩输入，然而驱动法兰46则是作为力矩输出。离合器42和力矩联轴器24和26，包括（图4）一个电磁体50和一个电枢52。两者都是环型配置在轴X上的。电枢52位于电磁体50里面，二者是被抗磨轴承和环型均匀的间隙g给分开的。g的间隙含有磁粉颗粒。在g里无磁场时，电磁体50和电枢52可以旋转，本质上没有联系。然而，当电流定向的通过电磁体52，电磁体52上的转矩会被转移到电枢54上。在大多数情况下这两者之间的一些滑移将要发生。电磁体50绕着安装了电刷58的周边滑环56进行调整到壳20。电刷58反过来被连接到一个电源，画出了相应的电位变化，并可以根据不同的电流来做电磁体52的磁场强度的管理。通过离合器42控制转矩的传递。离合器42中的电磁体50被离合器42的一个组件驱动法兰固定在靠近联轴器24和36的电机轴34的末端。因此，电磁体52的旋转与转子32同步。如果电磁铁52被通电，那么电磁体52的转矩被转移到电枢54。每个联轴器24和26中的行星组44包括（图4）一个太阳轮64，一个齿圈66和处于两者之间的行星齿轮68并且和太阳轮64、齿圈66啮合。此外，它还有一个安置在行星齿轮中心轴的行星架70。太阳轮64躺在轴X上，它的轴正好与轴X重回。它有一个短轴77，通过外花键和离合器42的电枢56相连。齿圈66是连接到离合器42上的电磁体54，并且连接电机轴34末端的驱动法兰40，所以，电磁体54和齿圈66在轴X上同步旋转，并且保持同样的角速度。行星架70有插脚74连接到行星齿轮68，所以，当行星齿轮68旋转时，插脚74也跟着旋转。插脚74在行星齿轮68中设立旋转轴。此外，行星架70还有一个通过桥壳20末端和适合驱动法兰46的主轴76。左半轴10通过一个万向节到驱动法兰46和左边的联轴器相连，而右半轴12通过另外一个万向节到驱动法兰46和右边联轴器26相连。电机22通过各自的联轴器24和26驱动两个半轴10和12。磁粉离合器24和26控制左右半轴10和12的力矩分布。在运行的驱动桥A中，电源装置6提供电机22所需的电流，使电机22的转子32和电机轴34绕轴X旋转。电机轴34将力矩传送到两个联轴器24和26。在每个联轴器24和26上，力矩从运转的电机22通过在联轴器24和26上的鼓40传到离合器42上的电磁体50，同时传到行星齿轮44上的齿圈66。在这里扭矩被分开。一步份扭矩从齿圈66通过行星齿轮68传到行星架70，并且从那里通过主轴76传到驱动法兰46。如果离合器42上的电磁体50是通电的，那么剩下的扭矩通过间隙g传到离合器42上的电枢52。电枢52旋转并且通过离合器42对行星组44的上的太阳轮64的作用改变扭矩，因为电枢52和太阳轮64是通过传动轴的尾端相连接的。太阳轮64旋转传递扭矩到行星齿轮68，在这里它将与齿圈66传递的扭矩相结合，所以行星架70和驱动法兰78看起来在鼓40上作用了力矩。换句话说，力矩流向联轴器24和26有两条路径，一条机械路径，包括齿圈68、行星齿轮68和行星架70，一条离合器路径包括电磁体50和离合器42上的电枢52，和行星组44上的太阳轮64、行星齿轮68和行星架70。大部分的力矩传递通过机械路径，两条路径传递的力矩分配是靠齿圈66和太阳轮64的齿数比U决定的。比例越高，则越少的扭矩通过离合器路径传递。扭矩在这两条路径间的关系可以用笛卡尔坐标表示（图5）。在这种安排上，对通过离合器42传递的扭矩一个小的改变，将导致通过离合器42的组件联轴器24和26传递的扭矩较大的变化，并且离合器42传递扭矩的大小取决于传送离合器42上的电磁体50的电流的大小。当转矩变化是，电流几乎线性通过电磁体50。通过控制两联轴器24和26上的离合器42的电流，扭矩能以最佳条件被分配到运行车辆A的两个驱动轮2和4上。例如，如果车辆A左转弯时，特别是高速左转弯时，比左驱动轮4更多的扭矩将被传递到右驱动轮2。因此两个联轴器24和26上的离合器42将有相应的调整。为此车辆A可以装备加速度计来决定侧面和纵向的加速度并做调整，所以调整的结果就是和速度传感器一样来决定两个半轴10和12的转速，因此更适用于车轮2和4的刹车系统。更多的传感器能决定方向盘的位置以及离合器42和刹车系统的温度。这些传感器产生信号并将信号传给车辆上的微处理器，微处理器将决定两个驱动轮2和4之间的扭矩分配，因此来控制两个联轴器10和12上的离合器42。一种改进的电驱动桥C（图6和7）同样的也能在车辆A运转的条件下按最佳比例分配左右驱动轮2和4之间的扭矩。它包括（图7）一个轴向通量电机84和封闭在一个壳86里的两个联轴器24和26，以及一个位于桥壳86里在电机84和联轴器24和26上的毂40之间的主传动器88。电机84包括一个定子92和一个转子94，以及安装在转子94上的电机轴96。电机轴96绕着轴Y旋转朝着直角上的轴X。主传动器88包括一个小齿轮轴100，它位于桥壳86里面在滚动轴承102上绕轴X旋转。传动轴100的一端和电机轴94连接，而另一端有一个斜齿轮104在上面。此外，主传动器88和传动轴106连接，传动轴延伸在鼓40和旋转轴X之间。传动轴的末端用花键和两个驱动鼓40配合连接，并且鼓40在桥壳86里面的轴承36上旋转。最后，主传动器88在联轴器24上的毂36上装有斜齿轮108。齿轮108和小齿轮104啮合。当电机84通电，将扭矩传递个小齿轮100。在传动轴100末端的小齿轮104绕着斜齿轮108旋转，斜齿轮旋转连接传动轴106和鼓40的末端。鼓40传递扭矩到联轴器24和26，这是它在驱动桥A中的功用。对于两个联轴器24和26来说，其他所谓的“环环相扣”是可能的，例如，离合器42上的电枢52可能与驱动鼓40有联系。同样由于离合器42被连接到驱动法兰46，离合器42和44在每个联轴器24和26中的位置也可以颠倒。TABLE-US-00001电驱动桥：A-汽车 B-电驱动桥 C-电驱动桥 X-轴 2-驱动轮 4-驱动轮 6-电源 8-支撑架 10-左半轴 12-右半轴 20-桥壳 22-电机 24-左联轴器 26-右联轴器 30-定子 32-转子 34-传动轴 36-轴承 40-驱动鼓 42-磁粉离合器 44-行星组 46-驱动法兰 50-电磁体 52-电枢 54-轴承 56-滑环 58-电刷 62、64-太阳轮 66-齿圈 68-行星齿轮 70-行星架 72-外半轴 74-插脚 76-主轴 84-电动机 86-桥壳 88-主传动器 90、92-定子 94-转子 96-电机轴 100-小齿轮轴 102-轴承 104-小齿轮 106-联接轴 108-直齿轮
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