An 8-stage dual-mode logic-power split combined transmission

Abstract

The present invention discloses an 8-stage dual-mode logic-power split combined transmission, which relates to the field of heavy vehicle transmissions and includes: a single-row confluence planetary gear set, an input shaft, a first planetary gear set, a second planetary gear set, four clutches, and two brakes. The modular dual-mode logic speed-changing unit and the series-combined structure are used to efficiently increase or decrease the gear modes, so as to achieve a large range of changes in the transmission ratio; a single-row confluence mechanism is selected to reduce the complexity of the speed-changing system structure, and the problem that it is difficult for the single-row confluence mechanism to achieve multi-stage stepless speed change is solved by adjusting the shifting elements and the displacement ratio of the variable pump; by preferably the positive and negative changes and the change range of the variable pump displacement, that is, by limiting the rotation speed and steering corresponding to the input of the hydraulic transmission part, the circulating power phenomenon of the confluence mechanism is avoided, and the output power of the confluence mechanism and the overall efficiency of the speed-changing system are improved.

Description

Technical Field

[0001] The present invention relates to the field of heavy vehicle transmissions, and particularly to an 8-stage dual-state logic-power split combined transmission. Background Art

[0002] With the continuous improvement of China's economic development level and the mechanization and intelligentization of key industries, the types of heavy vehicles in the fields of engineering, agriculture, and military are becoming more diverse, more widely used, and the technical requirements are becoming more advanced.

[0003] Different types of heavy vehicles have different requirements for the transmission system. In order to meet the power performance, economy, and operation convenience of drivers of heavy vehicles, the advanced transmissions currently applied to heavy vehicles mainly include: electronically controlled mechanical automatic transmission (AMT, stepped), power shift transmission (PST, stepped), dual-state logic transmission (BLT, stepped), hydrostatic transmission (HST, stepless), and hydro-mechanical continuously variable split transmission (HMCVT, stepless). Other types of transmissions, such as fully automatic hydraulic transmission (AT), dual-clutch automatic transmission (DCT), and metal belt continuously variable automatic transmission (CVT), cannot meet the usage requirements of various heavy vehicles due to their own transmission characteristics, load, cost, reliability, size, and structural complexity.

[0004] Among the transmissions currently used in heavy vehicles, the AMT has fewer gear stages and cannot achieve stepless speed change and power shift; the PST has more gear stages and can achieve power shift but also cannot achieve stepless speed change; the BLT has more gear positions and can largely reduce the shift shock and improve the shift smoothness, but the structure is complex and cannot achieve stepless speed change; the HST has advantages such as large transmission torque, small volume, and fast start, but due to the narrow high-efficiency area, the transmission efficiency is not high.

[0005] The current classic HMCVT can achieve stepless speed change. It divides the power output by the power source into two paths through a pair of gears. One path realizes stepless speed change through hydrostatic transmission, and the other path converges with it through a pair of gears and a planetary gear mechanism. Finally, the power is output through the planetary gear mechanism or a pair of gears. During the power transmission process, different stages of stepless speed change and power shift between different stages can be realized through a wet clutch. The converging mechanism couples the power flows of the mechanical transmission part and the hydraulic transmission part. While having the characteristics of stepless speed regulation and large load bearing of the hydraulic transmission part, the overall transmission efficiency of the transmission system is improved through the coupling with the mechanical transmission part.

[0006] Classic HMCVT confluence mechanisms mostly use double-row planetary gear mechanisms, and single-row confluence mechanisms are difficult to achieve coordination between multiple stages. Double-row confluence mechanisms achieve power coupling through the structure of front frame and rear ring (i.e., the planetary frame of the front planetary gear mechanism is consolidated with the gear ring of the rear planetary gear mechanism) or front ring and rear frame, but at the same time, this structure increases the complexity of the system and the difficulty of processing the planetary gear mechanism.

[0007] The classic HMCVT achieves stepless change of speed ratio by changing the displacement ratio through the change of the inclination angle of the variable pump swash plate, and then changes the gears through the corresponding shift actuator. One gear position corresponds to one shift actuator. In order to obtain a larger transmission ratio range, the transmission often has more shift actuators, which makes the system structure complicated and makes it inconvenient to add gears later.

[0008] The displacement ratio of the classic HMCVT variable displacement pump often changes from ε2 (the maximum displacement ratio selected) to ε1 (the minimum displacement ratio selected), and then from ε1 to ε2. The confluence mechanism is a differential gear system containing a double-row planetary gear mechanism. When the two input components in the differential gear system input a specific speed and direction, a circulating power phenomenon will occur, reducing the output power of the confluence mechanism and the overall efficiency of the transmission system.

[0009] In view of this, how to reduce the complexity of the power-split combination transmission system, realize multi-stage coordination of a single-row merging mechanism, reduce system complexity while increasing the stages to obtain a wide range of transmission ratios, solve the problem of circulating power in the merging mechanism, and further improve the overall efficiency of the transmission system are technical problems that people in this field urgently need to solve. Summary of the invention

[0010] The object of the present invention is to provide an 8-stage binary logic-power split combination transmission to solve the problems existing in the prior art.

[0011] To achieve the above object, the present invention provides the following solution: The present invention provides an 8-stage binary logic-power split combined transmission, comprising:

[0012] A convergent planetary gear, the convergent planetary gear comprising a convergent planetary gear center wheel, a convergent planetary gear planet carrier and a convergent planetary gear ring which are meshed and connected in sequence from the inside to the outside;

[0013] An input shaft, the input shaft is connected to the planet carrier of the convergent planetary gear through the first gear pair, the first transmission shaft and the second gear pair; and is connected to the central gear of the convergent planetary gear through the pump front gear pair, the variable pump, the quantitative motor, the motor rear gear pair and the second transmission shaft;

[0014] A first planetary row, wherein the converging planetary row gear ring is drivingly connected to the first planetary row via a third transmission shaft;

[0015] The second planetary gear set, the first planetary gear set is in transmission connection with the second planetary gear set, the second planetary gear set is in transmission connection with at least two clutches, and the clutches are in transmission connection with the output shaft;

[0016] The transmission ratio of the hydro-mechanical continuously variable transmission subsystem is i HM :

[0017]

[0018] where: k0 = the number of teeth of the ring gear of the compound planetary gear set ÷ the number of teeth of the sun gear of the compound planetary gear set;

[0019] i 01 is the transmission ratio of the first gear pair;

[0020] i 02 is the transmission ratio of the second gear pair;

[0021] i p is the transmission ratio of the gear pair in front of the pump;

[0022] i m is the transmission ratio of the gear pair behind the motor;

[0023] ε is the displacement ratio of the variable pump;

[0024] k0, i 01 , i 02 , i p , i m are fixed values, ε is a variable and its range of variation is [-1, 0], and i HM can vary continuously.

[0025] Furthermore, the first planetary gear set includes a first planetary gear set sun gear, a first planetary gear set planet carrier, and a first planetary gear set ring gear that are meshed and connected in sequence from the inside to the outside;

[0026] The first planetary gear set sun gear is in transmission connection with the third transmission shaft, the first planetary gear set sun gear is in transmission connection with the first planetary gear set ring gear through a first clutch, and the first planetary gear set ring gear is connected to a first brake, and the first brake can brake the first planetary gear set ring gear.

[0027] Furthermore, the second planetary gear set includes: a second planetary gear set sun gear, a second planetary gear set planet carrier, and a second planetary gear set ring gear that are meshed and connected in sequence from the inside to the outside;

[0028] The first planetary gear set planet carrier is in transmission connection with the second planetary gear set sun gear through a fourth transmission shaft, the second planetary gear set sun gear is in transmission connection with the second planetary gear set ring gear through a second clutch, and the second planetary gear set ring gear is connected to a second brake, and the second brake can brake the second planetary gear set ring gear.

[0029] Further, it further includes:

[0030] A third clutch, the carrier of the second planetary gear set is drivingly connected to the third clutch through a fifth transmission shaft, and the third clutch is drivingly connected to the output shaft through a third gear pair;

[0031] A fourth clutch, the carrier of the second planetary gear set is drivingly connected to the fourth clutch through a fifth transmission shaft, and the fourth clutch is drivingly connected to the output shaft through a fourth gear pair.

[0032] Further, when the first brake is disengaged, the first clutch is engaged, the second brake is engaged, the second clutch is disengaged, the third clutch is engaged, and the fourth clutch is disengaged, the transmission is in the first forward gear of the forward gear range;

[0033] When the first brake is disengaged, the first clutch is engaged, the second brake is engaged, the second clutch is disengaged, the third clutch is disengaged, and the fourth clutch is engaged, the transmission is in the second forward gear of the forward gear range;

[0034] When the first brake is disengaged, the first clutch is engaged, the second brake is disengaged, the second clutch is engaged, the third clutch is engaged, and the fourth clutch is disengaged, the transmission is in the third forward gear of the forward gear range;

[0035] When the first brake is disengaged, the first clutch is engaged, the second brake is disengaged, the second clutch is engaged, the third clutch is disengaged, and the fourth clutch is engaged, the transmission is in the fourth forward gear of the forward gear range;

[0036] When the first brake is engaged, the first clutch is disengaged, the second brake is engaged, the second clutch is disengaged, the third clutch is engaged, and the fourth clutch is disengaged, the transmission is in the first reverse gear of the reverse gear range;

[0037] When the first brake is engaged, the first clutch is disengaged, the second brake is engaged, the second clutch is disengaged, the third clutch is disengaged, and the fourth clutch is engaged, the transmission is in the second reverse gear of the reverse gear range;

[0038] When the first brake is engaged, the first clutch is disengaged, the second brake is disengaged, the second clutch is engaged, the third clutch is engaged, and the fourth clutch is disengaged, the transmission is in the third reverse gear of the reverse gear range;

[0039] When the first brake is engaged, the first clutch is disengaged, the second brake is disengaged, the second clutch is engaged, the third clutch is disengaged, and the fourth clutch is engaged, the transmission is in the fourth reverse gear of the reverse gear range.

[0040] Further, the transmission ratio corresponding to the first forward gear is i HM ×(1 + k2)×i1;

[0041] The transmission ratio corresponding to the second forward section is i HM ×(1 + k2)×i2;

[0042] The transmission ratio corresponding to the third forward section is i HM ×i1;

[0043] The transmission ratio corresponding to the fourth forward section is i HM ×i2;

[0044] The transmission ratio corresponding to the first reverse section is i HM ×(1 - k1)×(1 + k2)×i1;

[0045] The transmission ratio corresponding to the second reverse section is i HM ×(1 - k1)×(1 + k2)×i2;

[0046] The transmission ratio corresponding to the third reverse section is i HM ×(1 - k1)×i1;

[0047] The transmission ratio corresponding to the fourth reverse section is i HM ×(1 - k1)×i2;

[0048] Where k1 = the number of teeth of the ring gear of the first planetary gear set ÷ the number of teeth of the sun gear of the first planetary gear set, k2 = the number of teeth of the ring gear of the second planetary gear set ÷ the number of teeth of the sun gear of the second planetary gear set, i1 is the transmission ratio of the third gear pair, and i2 is the transmission ratio of the fourth gear pair. When the transmission switches between forward and reverse gear positions at the same gear position or between adjacent gear positions, the final transmission ratio of the previous gear position is equal to the starting transmission ratio of the next gear position.

[0049] Further, in the same gear position, the ratio between the maximum transmission ratio and the minimum transmission ratio is q, and in the same gear position and adjacent gear positions, the ratio q1 between the transmission ratios corresponding to the same variable pump displacement ratio is q1 = q.

[0050] The present invention discloses the following technical effects:

[0051] 1. The present invention couples the power flows of the mechanical transmission part and the hydraulic transmission part. While having the characteristics of stepless speed regulation and large load bearing of the hydraulic transmission part, it also improves the overall transmission efficiency of the speed change system through coupling with the mechanical transmission part.

[0052] The present invention can solve the problem of circulating power in the confluence mechanism, improve the output power of the confluence mechanism and the overall efficiency of the transmission system, and the technical effect is achieved in the following ways: 1. Limit the transmission ratio, direction and speed of the corresponding inputs of the mechanical transmission part and the hydraulic transmission part to avoid circulating power and improve the transmission efficiency of the system, wherein the direction and speed refer to the direction and speed of the fixed-displacement motor. By adjusting the inclination angle of the swash plate of the variable pump, the speed and direction of the fixed-displacement motor can be controlled, thereby controlling the speed and direction of the confluence planetary gear input, thereby avoiding circulating power. 2. The preferred range of the variable pump displacement ratio of the present invention is [-1, 0], and the hydrostatic transmission efficiency corresponding to this range is relatively high, which can effectively avoid power circulation. At the same time, the variable pump displacement ratio changes within a smaller range, which makes it easier to design the transmission controller and change the response characteristics of the transmission.

[0053] 2. The present invention can achieve the effect of multiple stage changes in the forward stage and the reverse stage by providing a second planetary gear and multiple clutches connected to the output shaft. The present invention can achieve stepless speed change with a large speed change range, and can provide technical support for the engine to be in the optimal working range for a long time.

[0054] 3. When switching gears, the final transmission ratio of the previous gear is equal to the initial transmission ratio of the next gear, which can greatly improve the smoothness of gear shifting and avoid the feeling of frustration when shifting gears.

[0055] 4. This application adopts a single-row convergent planetary gear, and the center wheel of the convergent planetary gear only moves in one direction, which can avoid the problem of fatigue failure caused by the bidirectional movement of the double-row convergent planetary gear, thereby improving the transmission stability, reliability and service life of each component. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0057] Figure 1 It is the overall structural layout diagram of the present invention;

[0058] Figure 2 It is the forward section variable pump displacement ratio-transmission ratio curve diagram;

[0059] Figure 3 It is the reverse stage variable pump displacement ratio-transmission ratio curve diagram;

[0060] Figure 4 This is the power flow diagram for the forward section;

[0061] Figure 5 It is the power flow direction diagram of the second stage of the forward section;

[0062] Figure 6 It is the power flow direction diagram of the third stage of the forward section;

[0063] Figure 7 It is the power flow direction diagram of the fourth stage of the forward section;

[0064] Figure 8 It is the power flow direction diagram of the first stage of the reverse section;

[0065] Figure 9 It is the power flow direction diagram of the second stage of the reverse section;

[0066] Figure 10 It is the power flow direction diagram of the third stage of the reverse section;

[0067] Figure 11 It is the power flow direction diagram of the fourth stage of the reverse section;

[0068] Among them, 1. input shaft; 2. pump front gear pair; 3. variable pump; 4. fixed-displacement motor; 5. motor rear gear pair; 6. sun gear carrier of the compound planetary gear train; 7. ring gear of the compound planetary gear train; 8. first brake; 9. sun gear carrier of the first planetary gear train; 10. second brake; 11. fourth transmission shaft; 12. sun gear carrier of the second planetary gear train; 13. central gear of the second planetary gear train; 14. third clutch; 15. fourth clutch; 16. output shaft; 17. fourth gear pair; 18. fifth transmission shaft; 19. third gear pair; 20. ring gear of the second planetary gear train; 21. second clutch; 22. central gear of the first planetary gear train; 23. ring gear of the first planetary gear train; 24. first clutch; 25. third transmission shaft; 26. second gear pair; 27. central gear of the compound planetary gear train; 28. second transmission shaft; 29. first transmission shaft; 30. first gear pair. Specific embodiments

[0069] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0070] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0071] Refer to Figure 1The embodiment of the present invention provides an 8-stage binary logic-power split combined transmission, including: a confluence planetary gear, the confluence planetary gear includes a confluence planetary gear center wheel 27, a confluence planetary gear carrier 6 and a confluence planetary gear ring 7 which are meshed and connected in sequence from the inside to the outside; an input shaft 1, the input shaft 1 is respectively connected to the confluence planetary gear carrier 6 through a first gear pair 30, a first transmission shaft 29 and a second gear pair 26; the input shaft 1 is connected to the confluence planetary gear center wheel 27 through a pump front gear pair 2, a variable pump 3, a quantitative motor 4, a motor rear gear pair 5 and a second transmission shaft 28; a first planetary gear, the confluence planetary gear ring 7 is connected to the first planetary gear through a third transmission shaft 25; a second planetary gear, the first planetary gear is connected to the second planetary gear, the second planetary gear is connected to at least two clutches, and the clutch is connected to the output shaft 16;

[0072] The transmission ratio of the hydraulic mechanical continuously variable transmission subsystem is i HM :

[0073]

[0074] Where: k0 = number of teeth on the planetary gear ring 7 ÷ number of teeth on the planetary gear center 27;

[0075] i 01 The first gear pair has a 30 gear ratio;

[0076] i 02 is the transmission ratio of the second gear pair 26;

[0077] i p is the transmission ratio of the pump front gear pair 2;

[0078] i m The gear ratio of the motor rear gear pair is 5;

[0079] ε is the displacement ratio of variable pump 3;

[0080] k0、i 01 、i 02 、i p 、i m is a quantitative variable, ε is a variable with a range of [-1, 0], i HM Capable of stepless change.

[0081] In this embodiment, the first planetary gear set includes a first planetary gear set sun gear 22, a first planetary gear set planet carrier 9, and a first planetary gear set ring gear 23 that are meshed and connected in sequence from the inside to the outside; the first planetary gear set sun gear 22 is drivingly connected to the third transmission shaft 25, the first planetary gear set sun gear 22 is drivingly connected to the first planetary gear set ring gear 23 through the first clutch 24, the first planetary gear set ring gear 23 is connected to the first brake 8, and the first brake 8 can brake the first planetary gear set ring gear 23. The second planetary gear set includes: a second planetary gear set sun gear 13, a second planetary gear set planet carrier 12, and a second planetary gear set ring gear 20 that are meshed and connected in sequence from the inside to the outside; the first planetary gear set planet carrier 9 is drivingly connected to the second planetary gear set sun gear 13 through the fourth transmission shaft 11, the second planetary gear set sun gear 13 is drivingly connected to the second planetary gear set ring gear 20 through the second clutch 21, the second planetary gear set ring gear 20 is connected to the second brake 10, and the second brake 10 can brake the second planetary gear set ring gear 20.

[0082] In this embodiment, it further includes: a third clutch 14, the second planetary gear set planet carrier 12 is drivingly connected to the third clutch 14 through the fifth transmission shaft 18, and the third clutch 14 is drivingly connected to the output shaft 16 through the third gear pair 19; a fourth clutch 15, the second planetary gear set planet carrier 12 is drivingly connected to the fourth clutch 15 through the fifth transmission shaft 18, and the fourth clutch 15 is drivingly connected to the output shaft 16 through the fourth gear pair 17. When the third clutch 14 and the fourth clutch 15 are in a separated state, they are idling on the fifth transmission shaft 18; when the third clutch 14 and the fourth clutch 15 are in a combined state, they are fixedly connected to the fifth transmission shaft 18. Power is transmitted from the fifth transmission shaft 18 to the output shaft 16 through the third clutch 14 (the fourth clutch 15) and the third gear pair 19 (the fourth gear pair 17). It can be said that the third clutch 14 connects the fifth transmission shaft 18 and the third gear pair 19; the fourth clutch 15 connects the fifth transmission shaft 18 and the fourth gear pair 17.

[0083] In this embodiment, both the forward gear position and the reverse gear position each include four gear positions.

[0084] When the first brake 8 is disengaged, the first clutch 24 is engaged, the second brake 10 is engaged, the second clutch 21 is disengaged, the third clutch 14 is engaged, and the fourth clutch 15 is disengaged, the transmission is in the first forward gear position of the forward gear position;

[0085] When the first brake 8 is disengaged, the first clutch 24 is engaged, the second brake 10 is engaged, the second clutch 21 is disengaged, the third clutch 14 is disengaged, and the fourth clutch 15 is engaged, the transmission is in the second forward gear position of the forward gear position;

[0086] When the first brake 8 is disengaged, the first clutch 24 is engaged, the second brake 10 is disengaged, the second clutch 21 is engaged, the third clutch 14 is engaged, and the fourth clutch 15 is disengaged, the transmission is in the third forward gear of the forward gear range;

[0087] When the first brake 8 is disengaged, the first clutch 24 is engaged, the second brake 10 is disengaged, the second clutch 21 is engaged, the third clutch 14 is disengaged, and the fourth clutch 15 is engaged, the transmission is in the fourth forward gear of the forward gear range;

[0088] When the first brake 8 is engaged, the first clutch 24 is disengaged, the second brake 10 is engaged, the second clutch 21 is disengaged, the third clutch 14 is engaged, and the fourth clutch 15 is disengaged, the transmission is in the first reverse gear of the reverse gear range;

[0089] When the first brake 8 is engaged, the first clutch 24 is disengaged, the second brake 10 is engaged, the second clutch 21 is disengaged, the third clutch 14 is disengaged, and the fourth clutch 15 is engaged, the transmission is in the second reverse gear of the reverse gear range;

[0090] When the first brake 8 is engaged, the first clutch 24 is disengaged, the second brake 10 is disengaged, the second clutch 21 is engaged, the third clutch 14 is engaged, and the fourth clutch 15 is disengaged, the transmission is in the third reverse gear of the reverse gear range;

[0091] When the first brake 8 is engaged, the first clutch 24 is disengaged, the second brake 10 is disengaged, the second clutch 21 is engaged, the third clutch 14 is disengaged, and the fourth clutch 15 is engaged, the transmission is in the fourth reverse gear of the reverse gear range.

[0092] The following table is a schematic table of the disengagement and engagement of each clutch and brake corresponding to each gear position:

[0093]

[0094] In this embodiment, the transmission ratio corresponding to the first forward gear is i HM ×(1 + k2)×i1;

[0095] The transmission ratio corresponding to the second forward gear is i HM ×(1 + k2)×i2;

[0096] The transmission ratio corresponding to the third forward gear is i HM ×i1;

[0097] The transmission ratio corresponding to the fourth forward gear is i HM ×i2;

[0098] The transmission ratio corresponding to the first reverse gear is i HM×(1 - k1)×(1 + k2)×i1;

[0099] The transmission ratio corresponding to the second reverse section is i HM ×(1 - k1)×(1 + k2)×i2;

[0100] The transmission ratio corresponding to the third reverse section is i HM ×(1 - k1)×i1;

[0101] The transmission ratio corresponding to the fourth reverse section is i HM ×(1 - k1)×i2;

[0102] Wherein, k1 = the number of teeth of the ring gear of the first planetary gear set ÷ the number of teeth of the sun gear of the first planetary gear set, k2 = the number of teeth of the ring gear of the second planetary gear set ÷ the number of teeth of the sun gear of the second planetary gear set, i1 is the transmission ratio of the third gear pair, i2 is the transmission ratio of the fourth gear pair. When the transmission switches between forward gears or reverse gears at the same gear position or between adjacent gear positions, the termination transmission ratio of the previous gear position is equal to the starting transmission ratio of the next gear position.

[0103] Such as Figure 2 and Figure 3 shown Figure 2 is the forward gear position variable pump 3 displacement ratio - transmission ratio curve graph, Figure 3 is the reverse gear position variable pump 3 displacement ratio - transmission ratio curve graph. When the transmission switches between the same gear position or between adjacent gear positions, the termination transmission ratio of the previous gear position is equal to the starting transmission ratio of the next gear position (it should be noted that within the same gear position, the gear positions can only be switched sequentially in order, and the adjacent gear position switch refers to switching from the first forward gear to the second forward gear, from the third forward gear to the second forward gear, etc.). For example, when the gear position switches from the first forward gear to the second forward gear, as Figure 2 shown, the termination transmission ratio i HM (ε = -1)×(1 + k2)×i1 of the first forward gear is equal to the starting transmission ratio i HM (ε = 0)×(1 + k2)×i2 of the second forward gear (note: Figure 2 and Figure 3 The curve changes from right to left, and the starting displacement ratio of each gear position is 0). Within the same gear position, the ratio between the maximum transmission ratio and the minimum transmission ratio is q. In the same gear position and between adjacent gear positions, the ratio q1 of the transmission ratios corresponding to the same variable pump 3 displacement ratio is q. For example, in the first forward gear, When the variable pump 3 displacement ratio is ε = -1, the ratio between the transmission ratios corresponding to the second forward gear and the first forward gear

[0104] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0105] The embodiments described above are only for describing the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An 8 - segment dual - state logic - power split combined transmission, characterized in that, Comprising: A compound planetary gear set, said compound planetary gear set including a compound planetary gear set sun gear (27), a compound planetary gear set planet carrier (6), and a compound planetary gear set ring gear (7) which are meshed and connected in sequence from inside to outside; An input shaft (1), said input shaft (1) being respectively in transmission connection with the compound planetary gear set planet carrier (6) through a first gear pair (30), a first transmission shaft (29), and a second gear pair (26); and being in transmission connection with the compound planetary gear set sun gear (27) through a pre-pump gear pair (2), a variable pump (3), a fixed-displacement motor (4), a post-motor gear pair (5), and a second transmission shaft (28); A first planetary gear set, said compound planetary gear set ring gear (7) being in transmission connection with the first planetary gear set through a third transmission shaft (25); A second planetary gear set, said first planetary gear set being in transmission connection with the second planetary gear set, said second planetary gear set being in transmission connection with at least two clutches, and said clutches being in transmission connection with an output shaft (16); The transmission ratio of the hydraulic mechanical continuously variable subsystem is i HM , wherein: k0 = number of teeth of the compound planetary gear set ring gear (7) ÷ number of teeth of the compound planetary gear set sun gear (27); i 01 is the transmission ratio of the first gear pair (30); i 02 is the transmission ratio of the second gear pair (26); i p is the transmission ratio of the front pump gear pair (2); i m is the transmission ratio of the motor rear gear pair (5); ε is the displacement ratio of the variable pump (3); k0, i 01 , i 02 , i p , i m is a fixed quantity, ε is a variable with a range of [-1, 0], and i HM can vary steplessly; By limiting the variation range of ε to [-1, 0] and limiting the transmission ratios corresponding to the inputs of the mechanical transmission part and the hydraulic transmission part, the rotation direction and speed of the fixed-displacement motor (4) to avoid circulating power; by adjusting the swash plate angle of the variable pump (3) to control the rotation speed and rotation direction of the fixed-displacement motor (4), thereby controlling the rotation speed and rotation direction of the input of the compound planetary gear set.

2. An 8-stage dual-state logic-power split combined transmission according to claim 1, characterized in that Said first planetary gear set includes a first planetary gear set sun gear (22), a first planetary gear set planet carrier (9), and a first planetary gear set ring gear (23) which are meshed and connected in sequence from inside to outside; Said first planetary gear set sun gear (22) is in transmission connection with the third transmission shaft (25), said first planetary gear set sun gear (22) is in transmission connection with the first planetary gear set ring gear (23) through a first clutch (24), and said first planetary gear set ring gear (23) is connected to a first brake (8), and said first brake (8) can brake the first planetary gear set ring gear (23).

3. An 8-stage dual-state logic-power split combined transmission according to claim 2, characterized in that, Said second planetary gear set includes: a second planetary gear set sun gear (13), a second planetary gear set planet carrier (12), and a second planetary gear set ring gear (20) which are meshed and connected in sequence from inside to outside; Said first planetary gear set planet carrier (9) is in transmission connection with the second planetary gear set sun gear (13) through a fourth transmission shaft (11), said second planetary gear set sun gear (13) is in transmission connection with the second planetary gear set ring gear (20) through a second clutch (21), and said second planetary gear set ring gear (20) is connected to a second brake (10), and said second brake (10) can brake the second planetary gear set ring gear (20).

4. An 8-section dual-state logic-power split combined transmission according to claim 3, characterized in that, Further comprising: A third clutch (14), said second planetary gear set planet carrier (12) is in transmission connection with the third clutch (14) through a fifth transmission shaft (18), and said third clutch (14) is in transmission connection with the output shaft (16) through a third gear pair (19); The fourth clutch (15), the second planetary carrier (12) is drivingly connected to the fourth clutch (15) through a fifth transmission shaft (18), and the fourth clutch (15) is drivingly connected to the output shaft (16) through a fourth gear pair (17).

5. The eight-stage two-state logic-power split combined transmission according to claim 4, characterized in that: When the first brake (8) is disengaged, the first clutch (24) is engaged, the second brake (10) is engaged, the second clutch (21) is disengaged, the third clutch (14) is engaged, and the fourth clutch (15) is disengaged, the transmission is in the first forward stage of the forward gear position; When the first brake (8) is disengaged, the first clutch (24) is engaged, the second brake (10) is engaged, the second clutch (21) is disengaged, the third clutch (14) is disengaged, and the fourth clutch (15) is engaged, the transmission is in the second forward stage of the forward gear position; When the first brake (8) is disengaged, the first clutch (24) is engaged, the second brake (10) is disengaged, the second clutch (21) is engaged, the third clutch (14) is engaged, and the fourth clutch (15) is disengaged, the transmission is in the third forward stage of the forward gear position; When the first brake (8) is disengaged, the first clutch (24) is engaged, the second brake (10) is disengaged, the second clutch (21) is engaged, the third clutch (14) is disengaged, and the fourth clutch (15) is engaged, the transmission is in the fourth forward stage of the forward gear position; When the first brake (8) is engaged, the first clutch (24) is disengaged, the second brake (10) is engaged, the second clutch (21) is disengaged, the third clutch (14) is engaged, and the fourth clutch (15) is disengaged, the transmission is in the first reverse stage of the reverse gear position; When the first brake (8) is engaged, the first clutch (24) is disengaged, the second brake (10) is engaged, the second clutch (21) is disengaged, the third clutch (14) is disengaged, and the fourth clutch (15) is engaged, the transmission is in the second reverse stage of the reverse gear position; When the first brake (8) is engaged, the first clutch (24) is disengaged, the second brake (10) is disengaged, the second clutch (21) is engaged, the third clutch (14) is engaged, and the fourth clutch (15) is disengaged, the transmission is in the third reverse stage of the reverse gear position; When the first brake (8) is engaged, the first clutch (24) is disengaged, the second brake (10) is disengaged, the second clutch (21) is engaged, the third clutch (14) is disengaged, and the fourth clutch (15) is engaged, the transmission is in the fourth reverse stage of the reverse gear position.

6. The eight-stage two-state logic-power split combined transmission according to claim 5, characterized in that: The transmission ratio corresponding to the first forward section is i HM ×1 + k2×i1; The transmission ratio corresponding to the second forward section is i HM ×1 + k2×i2; The transmission ratio corresponding to the third forward section is i HM ×i1; The transmission ratio corresponding to the fourth forward gear segment is i HM × i2; The transmission ratio corresponding to the first backward section is i HM ×1 - k1×1 + k2×i1; The transmission ratio corresponding to the second reverse section is i HM ×1 - k1×1 + k2×i2; The transmission ratio corresponding to the third reverse section is i HM ×1 - k1×i1; The transmission ratio corresponding to the fourth backward section is i HM ×1 - k1×i2; Among them, k1 = the number of teeth of the ring gear of the first planetary gear set ÷ the number of teeth of the sun gear of the first planetary gear set, k2 = the number of teeth of the ring gear of the second planetary gear set ÷ the number of teeth of the sun gear of the second planetary gear set, i1 is the transmission ratio of the third gear pair, and i2 is the transmission ratio of the fourth gear pair. When the transmission switches between forward gears or reverse gears at the same gear position or between adjacent gear positions, the final transmission ratio of the previous gear position is equal to the starting transmission ratio of the next gear position.

7. An 8 - segment dual - state logic - power split combined transmission according to claim 6, characterized in that: In the same gear position, the ratio between the maximum transmission ratio and the minimum transmission ratio of the transmission is q. In the same gear position and adjacent gear positions, the ratio q1 of the transmission ratios corresponding to the same variable pump displacement ratio is q.

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