中国地质大学长城学院本科毕业设计外文资料翻译系别工程技术系专业机械设计制造及其自动化学生姓名彭江鹤学号 05211534指导教师王泽河职称教授2015 年 5 月 4 日液压传动系统作者：Hopmans, ArthurH.摘要液压传动是由液压泵、液压控制阀、液压执行元件和液压辅件组成的液压系统。

液压泵把机械能转换成液体的压力能，液压控制阀和液压辅件控制液压介质的压力、流量和流动方向，将液压泵输出的压力能传给执行元件，执行元件将液体压力能转换为机械能，以完成要求的动作。

关键词：液压传动；气压传动；传动系统；许多液压传动先前已经设计出允许操作者无限变化输出的变速器，或甚至逆转的传动装置的输出作为相对于输入。

通常情况下，这已经通过使用一个旋转斜盘是要么由操作者手动或操作液压动机来改变通过旋转泵头部具有轴向移动的活塞流动的液压流体的。

液压流体从泵头活塞的流动，依次转动的马达头通过激励相应的一组活塞在其中违背一固定凸轮的，因此，旋转安装在电动机头的输出轴。

通常情况下，在现有技术的变速器已被被设置有各种功能，例如齿轮减速，刹车设定装置等。

不幸的是，这些功能通常是提供外部发送的和显著增加整个装置的体积和质量。

申请人确定，这是很期望具有其中基本上所有的这些需要或希望的功能，可以在内部提供的发送，同时还产生一个非常有效的和非常有效的传输的综合传输。

特别是，这种类型的变速器上经常使用的设备，如“零转动半径”剪草机之类的其中一个潜在的危险情况面对操作者，旁观者和设备本身，如果设备我们允许继续被推进应的操作者释放控制，由于当操作者无意中从装置抛出或变得受伤。

因此，“故障自动刹车”机制经常被设置为传输自动地返回到中立配置在这种情况下，使得该装置不会继续供电，如果控制被释放。

先前传输这种类型的一般依靠某种外部设备，比如其目的是为了在操作者控制轴返回到中立位置应操作者释放所述轴的反操作偏压弹簧。

这种类型的外部设备，可以容易地由用户或篡改损坏。

这种回归函数中性到传输本身的整合允许在外部零件的减少可被损坏或不适当取出并大大降低，以支持传输的各种功能所需的外部结构。

在这种类型的用于割草机的使用和类似的传输经常遇到的另一个问题是，操作时会略生涩或有弹性，因为操作者通常无法顺利地控制从一个速度到另一个的过渡，往往试图使突然变化。

从这些生涩的操作震动有一种倾向，穿更重的机器和操作上也是如此。

因此，理想的是抑制这种传输的输出，以防止这种不平稳的运动。

不仅是它是期望能够有一个返回到中立的功能，如desribed以上，但还希望为操作者有积极的感觉为中立位置时，不论操作者从空档移动到前进或从中立扭转。

此功能在本文中称为积极中性功能，并且在一般情况下，该功能需要操作者在从发送到任何一个正向或反向方向的中立姿势变换扩展更多的能量或运动相比，量能量消耗或运动需从一个速度转移到另一个在一个特定的方向。

与上面提到的其它特征，最好是需要提供此功能的结构的发送本身内掺入。

为了方便和简单起见，优选的是，发送直接从马达传动系接收电力而没有穿过齿轮减速装置。

不幸的是，大部分的输出要求是这样的，输出旋转速度必须大大降低相比，直接从马达所采取的输入转速。

因此，还希望该传输包含一个内部的齿轮减速系统允许大量减少输出速度比输入速度，即使当具有轴向移动的活塞驱动输出电动机的类型的液压传动装置的取向，以提供最大输出速度。

应注意的是，在一些比最大功率低输出速度时，几乎所有的可变输出传动装置本身提供的一些齿轮，由于一种或另一种电源旁路的减少，但没有已知的申请人的现有技术的变速器的提供大幅的内部的齿轮减速在全输出）。

某些使用这种类型的变速器的车辆包括制动器从而有效地防止车辆在电动机驱动的传输被停止移动。

这些制动器通常手动应用和要求的结构安装在车辆上的大量。

特别是，这种类型的驻车制动器通常包括：一个操作者的杠杆臂与相关联的键的杠杆臂连接到制动机构，这反过来，锁定驱动轮，传动轴或类似物。

再次，为了简化该结构和集成的制动功能到传输，它被认为是理想的申请人构建的发送，将有内部结构来自动接合驻车制动时的马达驱动的传送被停止。

虽然这种类型的驻车制动器是非常有利的，它也有必要提供一种具有倍率结构这将允许操作者选择性地覆盖制动这样的制动器;例如，当操作员希望对车辆推到不同的位置时，马达将无法启动。

此外，有利的是具有这种类型，它允许操作者选择性地接合时，电动机被操作的制动器的制动系统。

这允许操作者从车辆在电机，而不必担心车辆滚动下坡等的运行卸除。

申请人还认为有希望的是提供一种移植块地安装在泵头部和马达头其中将纳入必要流动通道的发送之间，止回阀等，以非常有效地和简单地提供用于流的流体围绕传动和消除需要用于连接泵头部和马达头软管。

移植块还设置有一个流体流旁路到允许操作者推动相关联的车辆没有流体锁定车辆的车轮的液压动作。

一个统一的传输本文中所描述的类型的进一步优选的特征包括，对于某些实施方案中，车辆车轮可以直接在传输的输出轴安装，而在车辆的相对侧透射驱动轮由单个输入驱动共同轴，还同时提供一个齿轮减速，如上所述，内部的传输。

这允许在部件高度有效的利用，并减少并为简化起见，在所得的载体。

可替代地，传输是足够柔韧的，对于一些实施例中，输入轴可以是成角度的相对于可以由泵头部和马达头变速器之间的移植块的修改来实现输出轴。

此外，积分电荷泵被确定为所希望的。

电荷泵由开关输入轴，其提供化妆液压流体到泵头部，同时允许循环流体用于冷却和过滤的驱动。

Hydraulic transmission systemMany hydraulic transmissions have been previously designed which allow an operator to infinitely vary the output of the transmission or even to reverse the output of the transmission as compared to the input. Normally, this has been accomplished by use of a swash plate which is either manually operated by the operator or hydraulically motivated to vary flow of hydraulic fluid through a rotating pump head having axially moving pistons. The flow of hydraulic fluid from the pump head pistons, in turn, rotates a motor head by motivating a corresponding set of pistons therein acting against a fixed cam and, consequently, rotates an output axle attached to the motor head.Typically, the prior art transmissions have been provided with various features such as gear reduction, brake setting equipment and the like. Unfortunately, these features are usually provided external of the transmission and significantly add to the volume and mass of the overall apparatus. Applicants determined that it was quite desirable to have an integrated transmission wherein substantially all of these necessary or desirable functions could be provided internally in the transmission, while also producing a highly effective and quite efficient transmission.In particular, transmissions of this type are frequently used on equipment such as "zero turning radius" lawnmowers and the like wherein a potentially dangerous situation confronts the operator, bystander and the equipment itself if the device us allowed to continue to be propelled should the operator release thecontrols, as when the operator is inadvertently thrown from the device or becomes injured. Therefore, a "deadman" mechanism is often provided for automatically returning the transmission to a neutral configuration in such a situation such that the device does not continue to be powered, if the controls are released.Previous transmissions of this type have generally relied on some kind of external device such as counter-operating biasing springs which are designed to return the operator control shaft to a neutral position should the operator release the shaft. External devices of this type can be easily tampered with by a user or damaged. Integration of such a return to neutral function into the transmission itself allows for a reduction in external parts which can be damaged or inappropriately removed and substantially reduces the external structure required to support various features of the transmission.Another problem frequently encountered in transmissions of this type for use in lawnmowers and the like is that operation tends to be somewhat jerky or bouncy, as the operator is usually unable to smoothly control the transition from one speed to another and often attempts to make abrupt changes. Vibration from such jerky operation has a tendency to wear more heavily on the machine and the operator as well. Consequently, it is desirable to dampen the output of such a transmission to prevent such jerky motion.Not only is it desirable to be able to have a return to neutral function, as desribed above, but it is also desirable for the operator to have a positive feel for the neutral position, whether the operator is moving from neutral to forward or from neutral to reverse. This feature is referred to herein as a positive neutral function and, in general, the feature requires that the operator extend more energy or movement in converting from the neutral orientation of the transmission to either a forward or reverse orientation, as compared to the amount of energy expended or movement required to transfer from one speed to another in a particular direction. As with the other features noted above, it is desirable that the structure required to provide this feature be incorporated within the transmission itself.For reasons of convenience and simplicity, it is preferable that the transmission receive power directly from the motor drive train without passing through gear reduction apparatus. Unfortunately, most output requirements are such that the output rotational speed must be substantially reduced as compared to the input rotational speed taken directly from the motor. Consequently, it is further desirable that the transmission incorporate an internal gear reduction system allowing for a substantial reduction in output speed as compared to input speed, even when the hydrostatic transmission of the type having axially moving pistons driving the output motor is oriented to provide the maximum output speed. (It is noted that at some lower than maximum output speeds, virtually all variable output transmissions inherently provide some gear reduction because ofpower bypass of one type or another, but none of the prior art transmissions known to applicants provide a substantial internal gear reduction at full output).Certain of the vehicles utilizing transmissions of this type include brakes which effectively prevent the vehicle from moving when the motor driving the transmission is stopped. These brakes are usually manually applied and require a substantial amount of structure mounted on the vehicle. In particular, parking brakes of this type have usually included an operator lever arm with an associated linkage connecting the lever arm to a brake mechanism which, in turn, locks the drive wheels, drive shaft or the like. Again, to simplify this structure and to integrate the braking function into the transmission, it was deemed desirable by applicants to construct a transmission which would have internal structure to automatically engage a parking brake when the motor driving the transmission was stopped.While a parking brake of this type is highly advantageous, it is also necessary to provide such a brake with an override structure which will allow the operator to selectively override the brake; for example, where the operator wishes to push the vehicle to a different position when the motor will not start. Further, it is advantageous to have a braking system of this type which allows the operator to selectively engage the brake when the motor is operating. This allows the operator to dismount from the vehicle while the motor is running without fear of the vehicle rolling downhill or the like.Applicants also deemed it desirable to provide a porting block mountable between the pump head and motor head of the transmission which would incorporate necessary flow channels, check valves and the like to very effectively and simply provide for flow of fluid about the transmission and to eliminate the need for hoses connecting the pump head and motor head. The porting block is also provided with a fluid flow bypass to allow an operator to push an associated vehicle without the hydraulic action of the fluid locking the wheels of the vehicle.Further desirable features of a unified transmission of the type described herein include that, for certain embodiments the vehicle wheels may be mounted directly on output shafts of the transmission, while transmission driving wheels on opposite sides of the vehicle are driven in common by a single input shaft, also while providing for a gear reduction, as described above, internal of the transmission. This allows for a highly efficient use of and reduction in parts and for simplicity in the resulting vehicle. Alternatively, the transmission is sufficiently flexible that for some embodiments, the input shaft may be angled relative to the output shaft which can be accomplished by modification of the porting block between the pump head and the motor head of the transmission. In addition, an integral charge pump was determined to be desirable. The charge pump is driven by the imput shaft which provides makeup hydraulic fluid to the pump head while allowing circulation of the fluid for cooling and filtering.。