主题：说几种中古坦克的散热 -- epimetheus

The Tiger was one of the first tanks to make widespread use of the double differential.

第一种广泛使用双差速的应该是虎式，（尽管不是严格的第一种，或是广义的第一种，但是最为著名的）

The more complex double differential system is similar to the controlled differential in basic concept, in that it controls the speed of the tracks by controlling the rotation of the idlers. However, in this case two complete differentials are used, one for each track, and the idlers are controlled not by a brake, but a second power shaft, the steering shaft.[3]

双差速转向系统是更加复杂的（和二级行星相比，需要有来自发动机、或者说来自变速箱之前的一路动力；需要连接两侧行星排的横轴，以及一侧反向惰轮），在理念上则是和控差速转向相同的（？），即通过控制一套惰轮来实现两侧转速的不同（克利夫兰可以广义地理解为使用双联外啮合行星排、以独特方式实现左右差动连接的双差速）。这需要两套差速装置，对应两套履带，而被控制的惰轮不是通过制动实现的，而是另一套转向流，转向传动轴。（这显然描述的是双行星汇流排实现的，下文中就有例外，即双中央差速桥实现的）

Normally the steering shaft is connected to the engine directly, instead of the output from the transmission. This means it spins at a relatively narrow range of RPM compared to the main drive shaft. The steering shaft is split into two output shafts through a clutch system that allows the outputs to spin forward, backward, or not at all. An idler reverses the direction on one side, so they always spin in opposite directions.[3]

通常转向传动轴连接到发动机，而不是传动的输出（变速器的输出），这样和直驶一路相比，转向流转速变化很小。通过离合器，这个转向流的传动轴以不同方式接通两侧的转向副轴，令其正传、反转、或是不转。两侧的“惰轮”是差动动作的，旋转方向相反（所谓的惰轮，往往是行星排的太阳轮。这里描述的是零差速的，实际上还能细分，可是既然下文中零独立单独分列出来，这就当是仅限于零差速的）

With the clutch off, so the shaft does not spin, the idlers in the two differentials are fixed in place. This is just like the controlled differential with the brake on. When the steering clutch is engaged, the shaft spins one of the idler sets forward and the other backward, causing one track to speed up and the other to slow down.[3]

离合器断开，则转向流的轴不会转动，两个差速器的“惰轮”将会是静止的，就像是控差速设计中制动器抱死一样（？？不应该是不施加制动么？brake的on、off难道含义特殊？）。离合器连接，这个轴令一侧“惰轮”前进、另一侧反转，令一侧输出轴加速另一侧减速。

Since the speed difference of the two tracks is independent of the gearbox selection, this makes the steering effect less pronounced at higher speeds; this means the tank has a longer turning radius at higher speeds, which is generally what is wanted. The system, however, produces only one radius for any given gearbox selection.[6]

由于两侧履带的速度差是档位无关的（从绝对转速的角度衡量，的确速度差是恒定的。行星排三个元件之间的角速度是线性加权关系，用于控制转动的太阳轮转速变化范围是档位无关的。之前的习惯是以转速比例表示的，犯了思维定势的错误。），这样在高速（高档位下）转向作用没有那么明显，也就是说高速的转向半径更大，这是一种很好的特性。不过这样的系统在一个档位下仅仅产生一个转向半径（取决于转向流本身有没有变速功能。S35是单一半径的机械实现，而虎式就不是，有两个半径，战后的HP250等等有两个、LSG3000有三个）

The system is fully regenerative: all of the engine's power reaches the track either through the main driveshaft or the steering system; none of the energy is being lost to brakes or clutches. Additionally, since power is fed around the transmission to the steering system, in some designs the tank can be turned even when the main gearbox is not engaged. The limitation on this feature is the strength of the steering shaft, which has to be strong enough to move the tank if this feature is desired, but otherwise can be made lighter if this is not needed.[6]

这种系统是完全再生的，所有的发动机动力通过主直驶路径或是转向路径来到两侧驱动轴，没有通过离合器被隔离或是被制动器消耗（然而再生的含义本身并不是动力输出到两侧驱动轴，而是内侧回收的功率的再利用！！例如双侧独立动力传动的再生问题就很值得推敲。没有再生能力的情况中，这个回收的动力或是被离合器隔离后消耗，或是和输入一起被制动器消耗。而动力的回收也要求内外两侧具有完全的连接，因此往往两个描述是伴生的，想要回收就有动力的连接传递。但是立意不同，需要强调的是，内侧经常是能量/功率流入而不是输出的）另外在某些设计中，由于双流的特性，即使主直驶一路不传递动力，动力也能通过转向流来到两侧，不过这一点需要转向的传动轴足够强壮，若是不需要这一特性，（也就是等同于原地转向），转向传动部分可以更加轻量化一些。（例如BMP3上的静液转向机就是较为羸弱的）

Double differentials were first used in experiments in France starting in 1921, and found on many heavy tanks of World War II, including the German Tigers. The addition of a continuously variable output using a hydrostatic transmission was used on the Char B1, providing smooth changes in turning radius that eliminated the system's main drawback. The low efficiency of this system meant it was not widely used, but rapid improvement in hydrodynamic fluid couplings made it common in the post-war era. Most Western tank designs since the 1960s have used a variation on this design, notably the M60 Patton and M1 Abrams.[6]

1921年法国首先实验双差速系统（前文不是还说英国1924年发明的吗？？？疑似是双中央差速桥的那个设计，而不是双汇流排实现的，其大量细节将不符合前述的描述），并且出现在很多二战重型坦克上，例如虎式（好像当时除此之外并不是很多啊）。使用连续可变液压\静液传动作为转向流，最早出现在法国的CharB1上，能够进行平滑的无极的转向（这是典型的双中央差速桥的设计，没有行星汇流排，尽管前文中的“惰轮”说法也没有明确表示行星排）。这个系统的低效的不足，意味着没法得到广泛的应用，但是到了战后，静液传动技术的发展快速弥补了这一不足。从60年代起，大量西方设计使用了这类设计，尤其是M60、M1（M60不是！！CD850是一种梅里特三差速系统，通过制动器控制转向！！！见下文）

The Churchill was the first tank to use the triple differential steering system.

最先用在丘吉尔上

This system was devised by Dr. H. E. Merritt, Director of Tank Design at Woolwich Arsenal, and manufactured by David Brown Ltd.

设计者是woolwich兵工厂坦克设计部门负责人亨利爱德华梅里特博士，生产方是大卫布朗公司

The triple differential is a modification to the double differential, replacing the steering clutches with a single braked differential similar to a controlled differential. This third differential produces any desired output speed in the steering shaft, compared to the double differential where the speed of the shaft is fixed. This output drives the steering idlers of an otherwise unchanged double differential, producing continuously variable steering. It has all the advantages of the double differential, while the only disadvantage is that the brake on the third differential dissipates some energy while slipping, but this is dependent only on the amount of energy being used to steer the vehicle, not the total energy being delivered to the tracks.[6]

这是一种修改的的双差速转向系统，将原本通过离合器控制的转向流以制动控制的差速器取代，就像是控差速系统一样（意思应该是仅仅需要操作两个制动器）。第三个差速器能够为转向流提供任意的转速，而不是双差速那种固定的速度。这个增加的制动的差速器两端的动力，驱动双差速系统中两个差速器的“惰轮”，产生任意连续变化的转向速度差。这种设计几乎具有双差速的所有优点（再生能力、较高的效率、转向行为和速度的匹配），而其主要的缺点是第三个差速器关联的制动器上滑动摩擦的损耗。但是这个缺点和这个差速器上需要传递的能量大小相关，整体上的效率还是较好的（威尔逊在40年代的报告中就曾经指出，在低速低档位下，三差速系统效率要比二级行星转向还差，而t54为例这时效率再低也基本是80%左右，这显然是因为低速下更多的能量从这个差苏桥传递，而此时本质上是大比例的功率通过一个差速器制动原理的环节传递，差速器制动环节消耗的能量很高、效率很低，典形的情况效率远低于50%，整体上拉低了转向系统效率。而又重又慢的“土龟”尽管能够做出较为灵活的动作，背后恐怕是深踩油门、拉杆拉到底）

The triple differential was used primarily on war-time and post-war British tanks, first on the Churchill tank and later on the Cromwell tank and its follow-on designs. It gave these designs unparalleled maneuverability and the ability to climb that was not matched by other designs until well into the Cold War. The basic version continued to be used on British designs until the TN 10 of the Conqueror and the TN 12 on the Chieftain. This system is generally not used today, in favour of improved hydrodynamic transmissions in the double differential, starting with the transmission in the Challenger.[6][7]

三差速系统主要应用在二战以及战后的英国坦克上，首先出现在丘吉尔，之后是克伦威尔……。这些坦克具有当时最好的操控性、最好的爬坡性能，直到冷战持续深入。最后的设计是征服者的TN10、酋长的TN12（蝎的TN15）。现在这些系统基本不使用了（海峡对岸还有，也就是前文中错误归类的CD850），现在设计的偏好是有着液力变速环节的双差速转向系统，英国从挑战者开始使用新设计。

The Panther was the sole operational user of the Maybach system.使用迈巴赫双差速的基本上只有黑豹

The Maybach system is essentially a simplified version of the double differential, or more accurately in mechanical terms, a double controlled differential. It replaces the double differential's forward and reverse steering shaft and clutch system with a single shaft that spins in one direction, and brakes on the idlers. Like the controlled differential, the brakes are normally applied to keep the idlers fixed. The steering inputs release one or the other brake to cause the idler to spin and that track to slow. Unlike the full double differential, the other side is not sped up so the system is not fully regenerative, and since both idler sets spin in the same direction, it does not offer neutral steering.[3]

迈巴赫双差速系统基本上是一种简化了的双差速系统，或者从机械的角度是一种双可控差速系统（问题是人家是左右独立变化的）。取代了双差速系统中可以正向或是反向旋转的副轴、离合系统，而仅仅使用一个单向旋转的轴、两侧“惰轮”的制动器。和控差速转向一样，直行中制动器发挥作用令“惰轮”固定。转向中，一侧的制动器释放，令“惰轮”开始旋转，这一侧的履带减速。不同于完整的双差速系统，另一侧的速度不会变化，因此，不是完全再生的。此外由于两侧的“惰轮”旋转方向相同，也不具有中心转向能力。（这里对于再生的理解还是存在分歧。再生的本意应该是功率\能量的回收，而不是整体速度的保持。黑豹进行规定半径的转向，这时从内侧回收的能量全部用于驱动外侧了，是完全再生的。此外，尽管黑豹没有中心转向能力，理论上当变速箱是空档，动力仅仅从一侧的太阳轮输入，负载作用下另一侧的齿圈会自动反转，还是可能实现中心转向的，尽管实际上黑豹转向流可能过于羸弱，强度不足以驱动整车）

The Maybach system was used only on a single design, the Panther tank. The late-war state of Germany's economy, especially machining capability and supply of strong materials, meant that only small numbers of the complex double differential could be produced. For the Panther, intended to be mass-produced, Maybach designed the AK7-200 transmission with a number of design notes intended to simplify production.

迈巴赫双差速系统仅有一个应用案例，即黑豹。战争后期德国的经济能力、尤其是机加工能力、高强度金属生产能力的制约，限制了复杂双差速系统的生产（最大的制约是在侧传动/终端减速器部分，而不是转向机本身，尽管转向机自身的参数不合适造成了这个问题的放大）。黑豹在设计的时候就强调生产性，其AK7-200传动系统设计中也有明显简化的意图。（相比于双差速的简化；或者说相对于基于行星排的等效离合传动的最小修改，在变速箱参数设计上与转向系统解耦）

While tracks could not be angled in their entirety, it was possible to put distort the track so that the tracked vehicle took a curved path. The front bogies on the British Universal Carrier were mounted on a crosstube that ran through the hull. Turning the steering wheel displaced the bogies to the left or right inducing a modest turn. Further turning of the wheel engaged braking on one side or the other. The Light Tank Mk VII Tetrarch used a similar system but the front wheels and two middle wheels on either side pivoted to induce the warp.[8]

UC载具使用车底横轴连接的悬挂组左右平移实现履带扭曲。而使用大轮子的郡主等等则是轮子自身的转动 （可以想象轮子和诱导齿之间的切割摩擦很厉害）。显然作为一种轻度的、大半径的转向方式，更小的半径还是需要进行施加制动力（从传承上是差速器制动模式，那么是不是有必要加上差速锁？）。

The Char Saint-Chamond used a petrol-electric transmission.Porsche's Elefant tank destroyer used a petrol-electric transmission, but proved highly unreliable.

Early steering systems were inefficient and lost so much power that they were ineffective for heavy vehicles. Holt Manufacturing Company (the ancestor of Caterpillar Inc.) whose track design influenced early tanks, experimented with a petrol-electric transmission in their Holt gas electric tank. A comparable design was used on the French Saint-Chamond and in turn adapted to be fitted in one British Mark II heavy tank to compete against other transmission developments including a Mk II fitted with a British Westinghouse petrol-electric and the original prototype heavy tank "Mother" with a Daimler petrol-electric drive. The winner was a conventional design with epicyclic gearboxes.[9] None of these were particularly successful, although several hundred units of the Saint-Chamond were produced.[10]

早期的转向系统效率不高，损失功率很大，于是不适用于重型车辆。霍尔特制造公司的履带设计影响了早期坦克，再其霍尔特油电坦克上实验了汽油电传系统。相似的角色是法国圣沙蒙，并且进一步影响了英国Mk2上的试装实验，和同时Mk2平台上的别的传动设计进行比较，保罗了威斯丁豪斯的油电传动、戴姆勒的油电传动。最后的胜利者是威尔逊的常规机械的行星排设计。那些油电传动在30吨级的英国坦克上面并不成功，尽管在法国圣沙蒙产量达到数百。

While moderately successful, these early systems were large and extremely heavy; the one in the Saint-Chamond added five tons.[10][11] The other designs, and follow-ons using a similar system, were generally dismissed as impractical.[11]

尽管仅仅是部分的成功，早期的电传系统体积很大、重量很重，例如圣沙蒙达的传动部分到了5吨。同时、后续的一些设计，也因此被认为无法实用。（齿轮的确可以在这个层面做到最好，后来的也是在齿轮基础上增加液压调速）

Some of the first attempts at new electric transmissions were made by the British in the early-war period for the TOG1 heavy tank design (a petrol engine drove twin generators which powered one electric motor per track), and by the Germans as part of mid-war experiments in heavy tanks. The most notable among the German efforts was the VK 4501 (P), a design by Porsche for a heavy tank which lost out to Henschel.[12] The 100 or so chassis from this rejected design were converted to a self-propelled anti-tank gun, the Elefant (initially "Ferdinand") Panzerjäger.[13] This style of transmission was also used in the super-heavy Panzer VIII Maus. In practice, the powertrain of the Porsche designs proved even less reliable than the traditional type, and by the late war era the supply of copper was too limited to consider using so much in drivetrain motors.[14]

在二战前英国TOG1上实验了新的电传动系统，含有一台汽油机带动两台发电机、驱动两侧的两个电机。德国在战争中期为重型坦克进行了实验，典形的是vk4501P，竞争虎式项目的垂直装甲的设计。虎式最后还是选择了亨舍尔的设计。大约提前生产的100辆的地盘被改装成为自行反坦克炮\歼击车，初期叫做斐迪南，后期叫做象。超重型的鼠式也实用了电传动。应用中，保时捷的设计要比亨舍尔的常规机械设计更加不可靠。等到战争后期铜的短缺也令电传动的生产变得不可能。

（保时捷电传动的可靠性到底怎么样？？按照找到的说法，最初比较中，即希特勒生日的那次，保时捷的4501由于转向中履带铲起过多泥土而陷车，这本身和传动无关，而同一天斐迪南上面是出现过发动机过热、机械故障等较多的问题，亨舍尔设计貌似并不优越。象式的过热问题，是不是加强散热风道就可以解决？？是不是存在电气损坏和机械损坏？？铜到底是不是42年战争中期制约电传动的主要因素？？）