外文資料--the file transmission gear selection of the basic parameters

1、<p>　　THE FILE TRANSMISSION GEAR SELECTION </p><p>　　OF THE BASIC PARAMETERS</p><p>　　1, Reasonable choice of module:</p><p>　　Modulus is an important gear basic parameters, th

2、e greater the modulus, the greater the tooth thickness, the bending strength of gear is also greater, and its greater carrying capacity. Instead modulus smaller tooth thickness will be thinner, the bending strength of ge

3、ar will be smaller. The low profile of the gear, due to the low rotational speed, torque, and gear of the relatively large bending stress, so need to choose a larger module in order to ensure its strength. And high-speed

4、 file gear,</p><p>　　In a modern gearbox design, the file selection module gear is different. For example, a transmission gear of a file to the five-gear gear module are: 3.5; 3; 2.75; 2.5; 2; to change over

5、 the past modulus or modulus of the same can not be the situation of Latin America.</p><p>　　2, a reasonable selection of pressure angle:</p><p>　　When a gear module and set the number of teeth,

6、 the gear diameter is determined, and the gear tooth involute base circle depends on the size, the size of the base circle and under pressure angle. For the same pitch circle of gear, if its pitch circle a different pres

7、sure angle, base circle is different. When the greater the pressure angle, the base circle diameter of the smaller, more curved involute, tooth root of the tooth will thicken, increase the tooth surface radius of curvatu

8、re, which can</p><p>　　For example: a gear module 3, the number of teeth of 30, when the pressure angle of 17.5 degrees for the circular tooth thickness of the base to 5.341; when the pressure angle of 25 de

9、grees, the tooth thickness of the base circle to 6.716; its base circle to increase the tooth thickness 25%, so increase the pressure angle to increase their flexural strength.</p><p>　　3, A reasonable selec

10、tion of Helix Angle:</p><p>　　Compared with the straight gear, helical gear drive with a smooth, coincidence degree, the impact is small and the advantages of small noise. As a result of the present with syn

11、chronous transmission, and transmission will no longer be a direct mobile gear meshing with another gear, but with all the gears are meshing, so that'll bring convenience to the use of helical gear, so to bring the g

12、earbox synchronizer Most of the use of helical gear.</p><p>　　Helical gear as a result of the characteristics of the entire tooth width decision not to enter the mesh at the same time all but one end of firs

13、t gear into the mesh, with the drive gear along the tooth width direction mesh gradually until all the teeth have wide access to mesh, so the actual meshing helical gear spur the region than the large. When the tooth whe

14、n a certain width, the contact ratio of helical gear with helix angle increases. Carrying capacity is also stronger, have better stabil</p><p>　　In the modern design of the gearbox, in order to ensure smooth

15、 gear drive, low noise and less impact, all . Files forgear should choose a larger helix angle, generally about 30 high-speed gear as a result of the higher speed, for a smooth, low impact, low noise, so the use of smal

16、l modulus, large helical angle; and low-profile gear module using the larger, smaller helix angle.</p><p>　　4, The perspective of a reasonable modification is selected:</p><p>　　With good condit

17、ions for the lubrication of the hardened gear is generally believed that the main danger is in the cycle under alternating stress, the fatigue crack Dedendum gradual expansion of the tooth root fracture caused by the fai

18、lure. Failure in the gear transmission is a part of this. In order to avoid a broken tooth, should be to maximize the tooth root bending strength, and the use is changed, and can achieve this objective. Under normal circ

19、umstances, the greater the coefficient, the </p><p>　　In the hardened gear, the tooth surface pitting failure is one of the reasons off. Increased engagement angle, can reduce the inter-tooth contact stress

20、and maximum slip rates, can greatly increase the ability of anti-pitting. And increased engagement angle, it must have a gear shift is introduced, thereby enhancing contact strength of tooth surface can improve the flexu

21、ral strength of tooth roots, so as to enhance the effect of the carrying capacity of gears. However, for helical gear drive, va</p><p>　　Therefore, in the design of a modern gearbox, the majority of all reas

22、onable use of gear shift is the angle in order to maximize its advantages. Mainly in the following design criteria:</p><p>　　low profile for the gear pair, the driving gear of the coefficient should be large

23、r than the passive gear shift coefficient, and pair of high-speed profile, the driving gear of the coefficient should be less than passive coefficient gear.</p><p>　　gear with the modification coefficient in

24、creased gradually stalls xiajiang. This is because low-grade zones as a result of low rotational speed, torque, and gear for high intensity, so the need to use more of the modification coefficient da.</p><p>

25、;　　The total of the gear profile shift coefficient is positive (of the angle shift as amended), and increased with the stalls and gradually decreased. The smaller the total coefficient, a pair of pair of tooth root of th

26、e thickness of the total will be thin, tooth root becomes weak, the lower the bending strength, but decreased as a result of the stiffness of the tooth, easy to absorb shock and vibration, so can reduce the noise. And to

27、oth contact ratio will increase, which bear a single tooth at t</p><p>　　5, to improve tip high coefficient:</p><p>　　Top gear in the transmission of high quality factor, the impact of focusing

28、on adaptation, in the main impact of helical gear contact ratio face. Coincidence degree by the end of the formula, we can see that when the number of teeth and meshing certain angle, the tooth tip is affected by tooth p

29、ressure angle coefficient of the top high impact factor the greater the high-tip, round tip the greater the pressure angle, contact ratio is The greater and ore stable drive. However, the high coefficient</p><

30、p>　　Top gear in the transmission of high quality factor, the impact of focusing on adaptation, in the main impact of helical gear contact ratio face. Coincidence degree by the end of the formula, we can see that when

31、the number of teeth and meshing certain angle, the tooth tip is affected by tooth pressure angle coefficient of the top high impact factor the greater the high-tip, round tip the greater the pressure angle, contact ratio

32、 is The greater and more stable drive. However, the high coefficien</p><p>　　The above is from the module, pressure angle, helix angle, coefficient and a high coefficient of this addendum to an independent a

33、nalysis of the five aspects of gear design trends. In fact between the various para-meters are inter-related, involved with each other, the choice of transmission parameters, it is necessary to take into account their st