行星齒輪減速器中英文翻譯英文資料

1、附錄 附錄附錄 1 ：英文原文Planetary GearsIntroductionThe Tamiya planetary gearbox is driven by a small DC motor that runs at about 10,500 rpm on 3.0V DC and draws about 1.0A. The maximum speed ratio is 1:400, giving an output speed

2、 of about 26 rpm. Four planetary stages are supplied with the gearbox, two 1:4 and two 1:5, and any combination can be selected. Not only is this a good drive for small mechanical applications, it provides an excellent r

3、eview of epicycle gear trains. The gearbox is a very well-designed plastic kit that can be assembled in about an hour with very few tools. The source for the kit is given in the References.Let's begin by reviewing th

4、e fundamentals of gearing, and the trick of analyzing epicyclic gear trains.Epicyclic Gear TrainsA pair of spur gears is represented in the diagram by their pitch circles, which are tangent at the pitch point P. The mesh

5、ing gear teeth extend beyond the pitch circle by the addendum, and the spaces between them have a depth beneath the pitch circle by the dedendum. If the radii of the pitch circles are a and b, the distance between the ge

6、ar shafts is a + b. In the action of the gears, the pitch circles roll on one another without slipping. To ensure this, the gear teeth must have a proper shape so that when the driving gear moves uniformly, so does the d

7、riven gear. This means that the line of pressure, normal to the tooth profiles in contact, passes through the pitch point. Then, the transmission of power will be free of vibration and high speeds are possible. We won

8、9;t talk further about gear teeth here, having stated this fundamental principle of gearing.The trick is that any motion of the gear train can carried out by first holding the arm fixed and rotating the gears relative to

9、 one another, and then locking the train and rotating it about the fixed axis. The net motion is the sum or difference of multiples of the two separate motions that satisfies the conditions of the problem (usually that o

10、ne element is held fixed). To carry out this program, construct a table in which the angular velocities of the gears and arm are listed for each, for each of the two cases. The locked train gives 1, 1, 1, 1 for arm, gear

11、 1, gear 2 and gear 3. Arm fixed gives 0, 1, -N1/N2, -N1/N3. Suppose we want the velocity ration between the arm and gear 1, when gear 3 is fixed. Multiply the first row by a constant so that when it is added to the seco

12、nd row, the velocity of gear 3 will be zero. This constant is N1/N3. Now, doing one displacement and then the other corresponds to adding the two rows. We find N1/N3, 1 + N1/N3, N1/N3 - N1/N2.The first number is the arm

13、velocity, the second the velocity of gear 1, so the velocity ratio between them is N1/(N1 + N3), after multiplying through by N3. This is the velocity ratio we need for the Tamiya gearbox, where the ring gear does not ro

14、tate, the sun gear is the input, and the arm is the output. The procedure is general, however, and will work for any epicyclic train.One of the Tamiya planetary gear assemblies has N1 = N2 = 16, N3 = 48, while the other

15、has N1 = 12, N2 = 18, N3 = 48. Because the planetary gears must fit between the sun and ring gears, the condition N3 = N1 + 2N2 must be satisfied. It is indeed satisfied for the numbers of teeth given. The velocity ratio

16、 of the first set will be 16/(48 + 16) = 1/4. The velocity ratio of the second set will be 12/(48 + 12) = 1/5. Both ratios are as advertised. Note that the sun gear and arm will rotate in the same direction.The best gene

17、ral method for solving epicyclic gear trains is the tabular method, since it does not contain hidden assumptions like formulas, nor require the work of the vector method. The first step is to isolate the epicyclic train,

18、 separating the gear trains for inputs and outputs from it. Find the input speeds or turns, using the input gear trains. There are, in general, two inputs, one of which may be zero in simple problems. Now prepare two row

19、s of the table of turns or angular velocities. The first row corresponds to rotating around the epicyclic axis once, and consists of all 1's. Write down the second row assuming that the arm velocity is zero, using th

20、e known gear ratios. The row that you want is a linear combination of these two rows, with unknown multipliers x and y. Summing the entries for the input gears gives two simultaneous linear equations for x and y in terms

21、 of the known input velocities. Now the sum of the two rows multiplied by their respective multipliers gives the speeds of all the gears of interest. Finally, find the output speed with the aid of the output gear train.