Planetary gearbox

Abstract

FIELD: planetary gearboxes.SUBSTANCE: planetary gearbox comprises a housing, a planetary mechanism with paired short and long satellites, five brakes and three clutches. The planetary mechanism comprises a small sun wheel connected to short satellites, a large sun wheel connected to long satellites, a first crown wheel connected to long satellites and an output shaft, and a second crown wheel connected to short satellites. The short and long satellites engage with each other and are mounted on the pinion carrier. The brakes connect the housing respectively to the large sun wheel, the second crown wheel and the pinion carrier, the body to the third crown wheel, the body to the second small crown wheel. Three clutches connect the input shaft to the pinion carrier, small sun wheel and large sun wheel respectively.EFFECT: operational capabilities of a self-propelled vehicle transmission with a planetary gearbox are expanded by increasing the number of gears to fourteen: ten forward gears and four reverse gears.1 cl, 1 dwg, 2 tbl

Description

[0001] The technical solution relates to transport engineering and is intended for use in transmissions of self-propelled vehicles.

[0002] Planetary gearboxes are widely used in transmissions of self-propelled vehicles for various purposes. There are planetary gearboxes containing an input (drive) shaft, an output (slave) shaft, a planetary mechanism with paired satellites, sun and crown wheels mounted on the carrier, all mounted in a housing. The main links of the planetary mechanism are equipped with clutches and brakes for connection with the input shaft and the housing (Filichkin N.V. Analysis of planetary gearboxes of transport and traction machines: Textbook. Computer version. - Chelyabinsk: Publishing house of SUSU, 2008). A disadvantage of such planetary gearboxes is the small number of stages - three or four forward gears and one reverse gear, which may be insufficient for the transmissions of machines operating in a wide range of loads.

[0003] The prototype chosen is the planetary gearbox, which is closest in technical essence to the proposed device, according to the Russian Federation patent for utility model No. 238489, comprising a housing, a planetary mechanism installed in the housing with paired short and long satellites, having a small sun wheel connected to the short satellites, a large sun wheel connected to the long satellites, a first crown wheel connected to the long satellites and an output shaft, a second crown wheel connected to the short satellites, wherein the short and long satellites engage with each other and are installed on the planet carrier, three brakes connecting the housing respectively with the large sun wheel, the second crown wheel and the planet carrier, and three clutches connecting the input shaft respectively with the planet carrier, the small sun wheel and the large sun wheel. The prototype has eight different gears: six forward gears and two reverse gears.The disadvantage of the prototype is the relatively small total number of forward and reverse gears when used in transmissions of self-propelled vehicles operated in difficult road conditions and off-road.

[0004] The objective of this invention is to expand the operational capabilities of the transmission of a self-propelled vehicle with a planetary gearbox, made on the basis of a planetary mechanism with paired satellites.

[0005] The stated problem is achieved in that a planetary gearbox comprising a housing, a planetary mechanism installed in the housing with paired short and long satellites, having a small sun wheel connected to the short satellites, a large sun wheel connected to the long satellites, a first crown wheel connected to the long satellites and an output shaft, a second crown wheel connected to the short satellites, wherein the short and long satellites engage with each other and are mounted on the planet carrier, three brakes connecting the housing respectively with the large sun wheel, the second crown wheel and the planet carrier, three clutches connecting the input shaft respectively with the planet carrier, the small sun wheel and the large sun wheel, is provided with a third crown wheel connected to the long satellites, a second large sun wheel connected to the long satellites, a fourth the brake connecting the third crown wheel to the body, the fifth brake,connecting the second small crown wheel to the body,

[0006] The figure shows the basic kinematic diagram of a planetary gearbox. Friction clutches and disc brakes are used as control elements.

[0007] The planetary gearbox components are mounted in a fixed housing 1. The planetary gearbox comprises an input shaft 2, an output shaft 3, a small sun wheel 4, a first large sun wheel 5, a second large sun wheel 6, a large crown wheel 7, a first small crown wheel 8 connected to the output shaft 3, and a second small crown wheel 9. Short satellites 11 and long satellites 12 are mounted on the carrier 10 and engage with each other. The short satellites 11 engage with the small sun wheel 4 and the large crown wheel 7. The long satellites 10 engage with the first large sun wheel 5, the second large sun wheel 6, the first small crown wheel 8, and the second small crown wheel 9.

[0008] Eight control devices are used to control the planetary gearbox: three clutches and five brakes. Planet carrier 8 is connected to input shaft 2 via clutch 13. Small sun wheel 4 is connected to drive shaft 2 via clutch 14. The first large sun wheel 5 is connected to drive shaft 2 via clutch 15. Brake 16 stops small sun wheel 4. Brake 17 stops the second large sun wheel 6. Brake 18 stops planet carrier 9. Brake 19 stops the second small crown wheel 9. Brake 20 stops the large crown wheel 7.

[0009] The planetary gearbox operates as follows. Rotation from the engine is transmitted to input shaft 2. In the initial (neutral) state, all clutches and brakes are disengaged, motion from input shaft 2 is not transmitted to output shaft 3. When the corresponding clutches and brakes are engaged in pairs, the planetary gearbox links are connected in a specific kinematic diagram, ensuring the corresponding gear ratio. The changed torque from the first small crown wheel 8 is transmitted to output shaft 3. The numbers of possible stages and the control elements engaged in this process (marked with the + symbol) are given in Tables 1 and 2. Direct transmission with a single gear ratio can be obtained in one of three ways by pairing clutches 13, 14, 15. The abbreviations PH and ZH denote the forward and reverse stages, respectively.

[0010] Table 1 shows the states of the planetary gearbox, provided that the numbers of teeth of all satellites 11 are the same, and wheels 5 and 6, 8 and 9 are equal in pairs.

[0011]

[0012] When simulating the operation of this planetary gearbox by enumerating all possible clutch and brake engagement options, it is theoretically possible to obtain sixteen possible gear ratios, including a single ratio for direct forward transmission. However, two of these sixteen options are inoperative:

[0013] 1) simultaneous engagement of clutch 13 and brake 18;

[0014] 2) simultaneous engagement of clutch 14 and brake 16.

[0015] These clutch and brake combinations block the operation of the planetary gearbox.

[0016] Of the remaining fourteen possible planetary gearbox states, with a common single planetary gear 12 engaging in five external engagements with central gears 6, 9, 5, 8, and planetary gear 11, only ten operational variants can be realized. Since long planetary gear 12 has a single gear ring, the planetary gearbox gear ratio for stages 7, 10, 12, and 13 is infinite, and no motion is transmitted from input shaft 2 to output shaft 3.

[0017] To overcome this limitation on the gear ratio and the number of operable stages, let us assume that the numbers of teeth of small central gears 6 and 5 and large central gears 9 and 8 will not be equal to each other. The difference in the number of teeth in this case may be one or two teeth due to the correction of the gear mesh geometry. With this approach, it is necessary to fulfill additional conditions of geometric synthesis: coaxiality, assembly, and proximity. Let us assume that the numbers of teeth of small central gears 6 and 5 are 29 and 31, respectively, and of large central gears 9 and 8 are 73 and 71, respectively, provided that three pairs of satellites 11 and 12 with a number of teeth equal to 20 and with the same center distance a are installed. wI =25.6⋅m for the first and third stages. And for the second stage, we will take the center distance a wII=31.2⋅m, and we obtain, based on the additional conditions of geometric synthesis, the following numbers of teeth: 20 for the small central wheel 4, 40 for the satellite 11 and 100 for the large central wheel 7. The external gear engagement of the satellites 11 and 12 will have an interaxial distance of a wIII =30.4⋅m.

[0018] Table 2 shows the states of the planetary gearbox under the condition that the numbers of teeth of the satellites 11, 12 and the central wheels 5 and 6, 8 and 9 are not equal.

[0019]

[0020] Thus, the proposed planetary gearbox, compared to the prototype, provides fourteen different stages: ten forward stages and four reverse stages using only one planetary mechanism with paired satellites. The proposed planetary gearbox can be used, in particular, in hydromechanical transmissions of cars and trucks, buses and tractors together with a hydrodynamic converter. The number of working stages in this planetary gearbox will depend on its operating conditions in a particular vehicle, which is determined by the purpose of the vehicle and the required gear ratios in the transmission. For example, stages with numbers 6, 7, 13 (Table2) with high gear ratios may be in demand, in particular, in transmissions of trucks, tractors, quarry dump trucks and off-road vehicles, depending on their operating conditions and the characteristics of the power plant (engine).

Claims

A planetary gearbox comprising a housing, a planetary mechanism mounted in the housing with paired short and long satellites, having a small sun wheel connected to the short satellites, a large sun wheel connected to the long satellites, a first crown wheel connected to the long satellites and an output shaft, a second crown wheel connected to the short satellites, wherein the short and long satellites engage with each other and are mounted on a planet carrier, three brakes connecting the housing respectively to the large sun wheel, the second crown wheel and the planet carrier, three clutches connecting the input shaft respectively to the planet carrier, the small sun wheel and the large sun wheel, characterized in that it is provided with a third crown wheel connected to the long satellites, a second large sun wheel connected to the long satellites, a fourth brake connecting the third crown wheel to the housing wheel, fifth brake,connecting the second small crown wheel to the body,

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