Four-planetary-row stepless speed change mechanism with hierarchical input and its speed change method

Abstract

The four planetary row continuously variable transmission mechanism with hierarchical input and its speed change method disclosed by the present invention belong to the technical field of continuously variable transmissions. It includes a first planetary row, a second planetary row, a third planetary row, and a fourth planetary row. The first sun gear on the first planetary row is connected to a transmission stage. The transmission stage includes a transmission gear A and a transmission gear B. The first ring gear on the first planetary row is connected to the second sun gear on the second planetary row through a first connecting shaft. The second ring gear on the second planetary row is connected to the third planet carrier on the third planetary row. The third planet carrier on the third planetary row is connected to the fourth sun gear on the fourth planetary row through a second connecting shaft. An output component is connected to the fourth planet carrier on the fourth planetary row. A one-way stopper is provided on one side of the same-speed connecting body. A transmission stage is additionally provided between the first planetary row of the four planetary row continuously variable transmission mechanism with hierarchical input of the present invention and the first driving part. The transmission ratio provided by the transmission stage broadens the power selection range of the first driving part.

Description

Technical Field

[0001] The present invention relates to the technical field of continuously variable transmissions, and particularly relates to a four planetary row continuously variable transmission mechanism with hierarchical input and its speed change method. Background Art

[0002] With the increasing social requirements for environmental protection, electric vehicle technology has become the mainstream research direction of major automobile manufacturers. Currently, most electric vehicles use a reducer with a fixed speed ratio. Although a large speed ratio reducer can be selected to meet the power requirements during vehicle starting and climbing, the large speed ratio limits the vehicle's ability to reach a high maximum speed, which is also the reason why the maximum speed of electric vehicles on the market is generally lower than that of fuel vehicles. In order to balance the vehicle's maximum speed and climbing ability, many automobile manufacturers have started to install AMT transmissions on electric vehicles. However, the AMT transmission belongs to a stepped transmission in principle and inherently has problems such as shift shock and power interruption; the transmission ratio range of the AMT transmission is restricted by the gear settings. When applied to heavy vehicles, in order to expand the transmission ratio range, a very large number of gears need to be set, resulting in a slow shift process and complex operation, which makes many large vehicle drivers reluctant to step on the brakes; the shift process of the AMT transmission relies on complex control strategies, making it difficult to grasp the accurate shift timing, resulting in high energy consumption and low efficiency; the structure of the AMT transmission is complex, with high manufacturing costs and difficult maintenance. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and design a four planetary row continuously variable transmission mechanism with hierarchical input and its speed change method.

[0004] To achieve the above object, the technical solution of the present invention is a four-planetary-row continuously variable transmission mechanism with hierarchical input, including a first planetary row, a second planetary row, a third planetary row, and a fourth planetary row. The first sun gear on the first planetary row is connected to a transmission stage. The transmission stage includes a transmission gear A and a transmission gear B. The transmission gear A and the transmission gear B are meshed through external teeth. The first ring gear on the first planetary row is connected to the second sun gear on the second planetary row through a first connecting shaft. The second ring gear on the second planetary row is connected to the third planet carrier on the third planetary row. The third planet carrier on the third planetary row is connected to the fourth sun gear on the fourth planetary row through a second connecting shaft. An output component is connected to the fourth planet carrier on the fourth planetary row. The first planet carrier on the first planetary row, the second planet carrier on the second planetary row, the third ring gear on the third planetary row, and the fourth ring gear on the fourth planetary row are all connected to a same-rotation-speed connecting body. A one-way stopper is provided on the same-rotation-speed connecting body. The first sun gear on the first planetary row is connected to the transmission gear A through a transmission shaft. The transmission gear B is connected to a first driving member through a first input shaft. The third sun gear on the third planetary row is connected to a second driving member through a second input shaft that sequentially passes through the second sun gear, the first connecting shaft, the first sun gear, the transmission shaft, and the transmission gear A.

[0005] As a further description of the present invention, the second sun gear, the first connecting shaft, the first sun gear, the transmission shaft, and the transmission gear A are all of a through-hollow structure.

[0006] As a further description of the present invention, the one-way stopper is used to limit the rotation directions of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear.

[0007] The present invention also provides a speed change method for a four-planetary-gear continuously variable transmission mechanism based on hierarchical input. The first driving member and the first sun gear are connected through a first input shaft, a transmission stage, and a transmission shaft, such that the rotational speed of the first driving member and the rotational speed of the first sun gear are in a proportional relationship according to the transmission ratio of the transmission stage; the second driving member and the third sun gear are connected through a second input shaft, such that the rotational speed of the second driving member and the rotational speed of the third sun gear are the same; the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are all connected to the same-rotational-speed connecting body, such that the rotational speeds of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are the same; the first ring gear and the second sun gear are connected through a first connecting shaft, such that the rotational speed of the first ring gear and the rotational speed of the second sun gear are the same; the second ring gear is connected to the third planet carrier, and the third planet carrier is connected to the fourth sun gear through a second connecting shaft, such that the rotational speeds of the second ring gear, the third planet carrier, and the fourth sun gear are the same; the fourth planet carrier is connected to the output member, such that the rotational speed of the fourth planet carrier and the rotational speed of the output member are the same.

[0008] As a further description of the present invention, it is set that: the rotational speed of the first sun gear is N1, the transmission ratio of the transmission stage is i, the rotational speed of the first driving member is N1×i, the rotational speeds of the second driving member and the third sun gear are N2, the rotational speeds of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are N3, the rotational speeds of the first ring gear and the second sun gear are N4, the rotational speeds of the second ring gear, the third planet carrier, and the fourth sun gear are N5, and the rotational speeds of the fourth planet carrier and the output member are N6; when any two of the values of N1, N2, N3, N4, N5, and N6 are determined, the other four values can be calculated through the proportional relationship of the line segments in the vector diagram; by driving the first driving member and the second driving member to adjust and control the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear, continuous stepless change of the rotational speed N6 of the output member is achieved. Among them, when the rotational speed N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear is 0, the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear is set as P; by driving the first driving member and the second driving member to adjust and control the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear, the output states of the output member include state A, state B, state C, state D, and state E.

[0009] As a further description of the present invention, in the state A, the rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are 0. The first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear to be P, and the rotation directions are both positive, so that the rotation direction of the rotational speed N6 of the output member is positive. At this time, the transmission ratio is in the maximum state.

[0010] As a further description of the present invention, in the state B, the rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are not 0, and the rotation direction is positive. The first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear to be less than P, and the rotation directions are both positive, so that the rotation direction of the rotational speed N6 of the output member is positive.

[0011] As a further description of the present invention, in the state C, the rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear are not 0, and the rotation direction is reverse. The first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear to be greater than P, and the rotation directions are both positive. At this time, the rotation direction of the rotational speed N6 of the output member is reverse. In order to avoid the situation where the rotation direction of the rotational speed N6 of the output member is reverse, a one-way stopper is provided on the same-speed connecting body connected to the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear. The one-way stopper restricts the rotation direction of the rotational speed N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear to be only positive and not reverse, so that the rotation direction of the rotational speed N6 of the output member is always positive.

[0012] As a further description of the present invention, in the state D, the first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear to be 1, and the rotation directions are both positive, so that the rotational speed N6 of the output member is equal to the rotational speeds N1 of the first sun gear and N2 of the third sun gear in magnitude, and the rotation directions are both positive. At this time, the transmission ratio is 1.

[0013] As a further description of the present invention, in the state E, the first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear to be less than 1, and the rotation directions are both positive, so that the rotational speed N6 of the output member is greater than the rotational speeds N1 of the first sun gear and N2 of the third sun gear, and the rotation direction is positive.

[0014] As a further illustration of the present invention, when the first driving member fails, the second driving member drives the third sun gear at a rotational speed of N2 and in the forward direction. The rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear have a reverse tendency. At this time, the one-way stopper restricts their reverse rotation, making the rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear zero. The rotational speed N6 of the output member rotates in the forward direction, and the power of the second driving member is output through the third planetary gear set and the fourth planetary gear set after decelerating and increasing torque.

[0015] As a further illustration of the present invention, when the second driving member fails, the first driving member drives the first sun gear at a rotational speed of N1 and in the forward direction. The rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear have a reverse tendency. At this time, the one-way stopper restricts their reverse rotation, making the rotational speeds N3 of the first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear zero. The rotational speed N6 of the output member rotates in the forward direction, and the power of the first driving member is output through the first planetary gear set, the second planetary gear set, and the fourth planetary gear set after decelerating and increasing torque.

[0016] The four-planetary-gear continuously variable transmission mechanism with hierarchical input and its speed change method provided by the present invention change the transmission ratio between the input end and the output end by adjusting the rotational speeds of the first driving member and the second driving member and through the cooperation among the first planetary gear set, the second planetary gear set, the third planetary gear set, the fourth planetary gear set, and the one-way stopper, realizing stepless speed change at the output end. This speed change mechanism has the advantages of high transmission efficiency, large output torque, no power interruption, simple and reliable structure, low manufacturing cost, easy maintenance, and simple and convenient speed regulation. In addition, a transmission stage is provided between the first input shaft and the transmission shaft in the four-planetary-gear continuously variable transmission mechanism with hierarchical input of the present invention. The transmission stage changes the transmission ratio between the first driving member and the first sun gear by changing the tooth number ratio of the transmission gear A and the transmission gear B. Therefore, on the premise of achieving the same use effect, the transmission ratio provided by the transmission stage broadens the power selection range of the first driving member. Brief Description of the Drawings

[0017] Figure 1 is a schematic diagram of the four-planetary-gear continuously variable transmission mechanism with hierarchical input provided by an embodiment of the present invention;

[0018] Figure 2 is a rotational speed vector diagram of the first planetary gear set, the second planetary gear set, the third planetary gear set, and the fourth planetary gear set provided by an embodiment of the present invention;

[0019] Figure 3 is a rotational speed vector diagram obtained by combining the first planetary gear set, the second planetary gear set, the third planetary gear set, and the fourth planetary gear set provided by an embodiment of the present invention;

[0020] Figure 4 It is a rotational speed vector diagram when the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear provided by the embodiment of the present invention is less than P;

[0021] Figure 5 It is a rotational speed vector diagram when the magnitude ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear provided by the embodiment of the present invention is greater than P;

[0022] Figure 6 It is a rotational speed vector diagram when the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the second sun gear provided by the embodiment of the present invention is equal to 1;

[0023] Figure 7 It is a rotational speed vector diagram when the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the second sun gear provided by the embodiment of the present invention is less than 1;

[0024] Figure 8 It is a rotational speed vector diagram when the rotational speed N1 of the first sun gear provided by the embodiment of the present invention remains unchanged and the rotational speed N2 of the third sun gear is adjusted;

[0025] Figure 9 It is a rotational speed vector diagram when the rotational speed N2 of the third sun gear provided by the embodiment of the present invention remains unchanged and the rotational speed N1 of the first sun gear is adjusted;

[0026] Figure 10 It is a rotational speed vector diagram when the first driving member fails and the rotation direction of the third sun gear is positive provided by the embodiment of the present invention;

[0027] Figure 11 It is a rotational speed vector diagram when the second driving member fails and the rotation direction of the first sun gear is positive provided by the embodiment of the present invention;

[0028] Figure 12 It is a rotational speed vector diagram when the ratio of the rotational speed N1 of the first sun gear and the rotational speed N2 of the third sun gear provided by the embodiment of the present invention is equal to P and their rotation directions are both reverse.

[0029] Reference numerals:

[0030] 1 - First planetary gear set, 101 - First sun gear, 102 - First planet carrier, 103 - First ring gear, 2 - Second planetary gear set, 201 - Second sun gear, 202 - Second planet carrier, 203 - Second ring gear, 3 - Third planetary gear set, 301 - Third sun gear, 302 - Third planet carrier, 303 - Third ring gear, 4 - Fourth planetary gear set, 401 - Fourth sun gear, 402 - Fourth planet carrier, 403 - Fourth ring gear, 5 - Transmission stage, 501 - Transmission gear A, 502 - Transmission gear B, 6 - First input shaft, 7 - Second input shaft, 8 - First connecting shaft, 9 - Second connecting shaft, 10 - Output component, 11 - One - way stopper, 12 - Transmission shaft. Detailed implementation mode

[0031] First of all, we need to explain the purpose of applying for the embodiments of the present invention. We aim to solve the problems existing in AMT transmissions, such as jerky shifting and power interruption inherent in AMT transmissions; the transmission ratio range of AMT transmissions is restricted by gear settings. When applied to heavy - duty vehicles, to expand the transmission ratio range, a large number of gears need to be set, resulting in a slow shifting process and complex operation, which is the reason why many truck drivers are reluctant to step on the brakes; the shifting process of AMT transmissions relies on complex control strategies, making it difficult to grasp the accurate shifting timing, and there are problems of high energy consumption and low efficiency; the structure of AMT transmissions is complex, with high manufacturing costs and difficult maintenance. Therefore, a four - planetary - row continuously variable transmission mechanism with hierarchical input is proposed to solve the existing problems.

[0032] The following will specifically describe the embodiments of the present invention with reference to the accompanying drawings. First, we will introduce the specific structure of the embodiments of the present invention.

[0033] See Figure 1, the four planetary row continuously variable transmission mechanism with hierarchical input according to the embodiment of the present invention includes a first planetary row 1, a second planetary row 2, a third planetary row 3, and a fourth planetary row 4. The first sun gear 101 on the first planetary row 1 is connected to a transmission stage 5. The transmission stage 5 includes a transmission gear A 501 and a transmission gear B 502, and the transmission gear A 501 and the transmission gear B 502 are meshed by external teeth. The first ring gear 103 on the first planetary row 1 is connected to the second sun gear 201 on the second planetary row 2 through a first connecting shaft 8. The second ring gear 203 on the second planetary row 2 is connected to the third planet carrier 302 on the third planetary row 3. The third planet carrier 302 on the third planetary row 3 is connected to the fourth sun gear 401 on the fourth planetary row 4 through a second connecting shaft 9. An output component 10 is connected to the fourth planet carrier 402 on the fourth planetary row 4. The first planet carrier 102 on the first planetary row 1, the second planet carrier 202 on the second planetary row 2, the third ring gear 303 on the third planetary row 3, and the fourth ring gear 403 on the fourth planetary row 4 are all connected to the same-speed connecting body. A one-way stopper 11 is provided on one side of the same-speed connecting body. The first sun gear 101 on the first planetary row 1 is connected to the transmission gear A 501 through a transmission shaft 12. The transmission gear B 502 is connected to a first driving member through a first input shaft 6. The third sun gear 301 on the third planetary row 3 is connected to a second driving member through a second input shaft 7 that sequentially passes through the second sun gear 201, the first connecting shaft 8, the first sun gear 101, the transmission shaft 12, and the transmission gear A 501.

[0034] See Figure 1 , the first planetary row 1 includes a first sun gear 101, a first planet carrier 102, and a first ring gear 103. The second planetary row 2 includes a second sun gear 201, a second planet carrier 202, and a second ring gear 203. The third planetary row 3 includes a third sun gear 301, a third planet carrier 302, and a third ring gear 303. The fourth planetary row 4 includes a fourth sun gear 401, a fourth planet carrier 402, and a fourth ring gear 403. In practical applications, the second sun gear 201, the first connecting shaft 8, the first sun gear 101, the transmission shaft 12, and the transmission gear A 501 are all designed with a through hollow structure. The one-way stopper 11 is used to limit the rotation direction of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403.

[0035] Next, we need to describe the speed change method of the four planetary row continuously variable transmission mechanism based on hierarchical input in combination with the specific structure of the embodiment of the present invention.

[0036] According to the basic principle of planetary gears, if the speeds of any two of the three components of the sun gear, the ring gear, and the planet carrier are determined, the speed of the other component is also determined, and their speed relationship is in a corresponding proportional relationship according to the number of teeth of the sun gear and the number of teeth of the ring gear.

[0037] According to the basic principle of planetary gears, when the rotational speeds of any two of the three components, namely the sun gear, the ring gear, and the planet carrier, are the same, the rotational speed of the other component is also the same.

[0038] Therefore, the rotational speed of the first sun gear 101 is N1, the transmission ratio of the transmission stage 5 is i, and the rotational speed of the first driving member is N1×i; the rotational speeds of the second driving member and the third sun gear 301 are the same, designated as N2; the rotational speeds of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403 are the same, designated as N3; the rotational speeds of the first ring gear 103 and the second sun gear 201 are the same, designated as N4; the rotational speeds of the second ring gear 203, the third planet carrier 302, and the fourth sun gear 401 are the same, designated as N5; the rotational speeds of the fourth planet carrier 402 and the output member 10 are the same, designated as N6.

[0039] According to the rotational speed vector calculation method of planetary gears, the rotational speed vector diagrams of the first planetary gear set 1, the second planetary gear set 2, the third planetary gear set 3, and the fourth planetary gear set 4 are obtained, as Figure 2 shown. Figure 2 In the figure, the length of the line segment represents the magnitude of the rotational speed, and the arrow direction represents the rotational speed direction. It is defined that the upward arrow is the positive rotation direction, and the downward arrow is the reverse rotation direction.

[0040] Combining the rotational speed vector diagrams of the first planetary gear set 1, the second planetary gear set 2, the third planetary gear set 3, and the fourth planetary gear set 4, the rotational speed vector diagram as shown in Figure 3 is obtained.

[0041] Refer to Figure 3 , when any two of the values of N1, N2, N3, N4, N5, and N6 are determined, the other four values can be calculated through the proportional relationship of the line segments in the vector diagram. That is, when the rotational speed N1×i of the first driving member is determined and the rotational speed N2 of the second driving member is determined, then the rotational speed N6 of the output member 10 is also uniquely determined. By adjusting the rotational speed N1×i of the first driving member and the rotational speed N2 of the second driving member to control the rotational speed N1 of the first sun gear 101 and the rotational speed N2 of the third sun gear 301, continuous stepless variation of the rotational speed N6 of the output member 10 can be achieved.

[0042] Next, the speed change principle of the four-planetary-gear stepless speed change mechanism with hierarchical input according to the embodiments of the present invention will be described in combination with specific working conditions.

[0043] 1. Starting condition

[0044] Refer to Figure 3, when starting, it starts to accelerate. The first driving part and the second driving part control the rotational speeds N1 of the first sun gear 101 and N2 of the third sun gear 301 to be both positive in terms of steering, and control the ratio of the rotational speed N1 of the first sun gear 101 to the rotational speed N2 of the third sun gear 301 to be equal to P in terms of rotational speed. The rotational speed N6 of the output component 10 is gradually accelerated, and the steering is positive. In this working condition, the power of the first driving part and the second driving part is coupled together, output with deceleration and increased torque, so that the vehicle accelerates forward.

[0045] 2. Acceleration and deceleration working conditions

[0046] See Figure 4 , when accelerating and decelerating, the first driving part and the second driving part control the steering of both the first sun gear 101 and the third sun gear 301 to be positive in terms of steering, and control the ratio of the rotational speed N1 of the first sun gear 101 to the rotational speed N2 of the third sun gear 301 to be less than P in terms of rotational speed. By controlling the magnitudes of the rotational speeds N1 of the first sun gear 101 and N2 of the third sun gear 301 and the degree of acceleration and deceleration by the first driving part and the second driving part, the rotational speed N6 of the output component 10 can be gradually increased or decreased, the steering is positive, so that the vehicle accelerates or decelerates forward.

[0047] In addition, as Figure 8 shown, the speed regulation methods for acceleration and deceleration can also be to maintain the rotational speed N1 of the first sun gear 101 unchanged by the first driving part, and adjust the magnitude of the rotational speed N2 of the third sun gear 301 by the second driving part to adjust the magnitude of the rotational speed N6 of the output component 10; as Figure 9 shown, it can also be to maintain the rotational speed N2 of the third sun gear 301 unchanged by the second driving part, and adjust the magnitude of the rotational speed N1 of the first sun gear by the first driving part to adjust the magnitude of the rotational speed N6 of the output component 10. Therefore, in the process of accelerating or decelerating the rotational speed N6 of the output component 10, the first driving part and the second driving part can control the acceleration, deceleration and speed maintenance of the first driving part and the second driving part according to their respective high-efficiency working areas and the current working condition of the control system. In this way, both the first driving part and the second driving part can work in their respective high-efficiency working areas for a long time, thus achieving the effect of energy saving.

[0048] 3. Maximum vehicle speed working condition

[0049] See Figure 6 , when the first driving part and the second driving part control the magnitudes of the rotational speeds N1 of the first sun gear 101 and N2 of the third sun gear 301 to be equal, the steering is both positive, and both reach the maximum rotational speed, the rotational speed N6 of the output component 10 is also equal to the rotational speeds N1 of the first sun gear 101 and N2 of the third sun gear 301. It can be set that the vehicle reaches the maximum vehicle speed in this state.

[0050] See Figure 7 , if the vehicle needs to reach a higher speed when it has reached the above maximum speed state, the rotation speed N1×i of the first driving part can be reduced, and the rotation speed N1 of the first sun gear 101 will also be relatively reduced. The second driving part maintains the rotation speed N2 of the third sun gear 301 at the maximum speed unchanged, so that the rotation speed N6 of the output part 10 continues to increase. The maximum speed is determined by the magnitude of the rotation speed N6 of the output part 10, and the magnitude of the rotation speed N6 of the output part 10 can be set by controlling the rotation speed N1×i of the first driving part and the rotation speed N2 of the second driving part. Therefore, as long as a first driving part with a lower rotation speed is selected, a very high output rotation speed can be achieved, and the power requirement for the used driving part is further reduced.

[0051] For the above-mentioned starting condition and acceleration / deceleration condition, the occurrence of a dangerous condition needs to consider how to avoid it.

[0052] Example: See Figure 5 , when the rotation speed control of the first driving part and the second driving part is inaccurate or the control fails, and the ratio of the magnitude of the rotation speed N1 of the first sun gear 101 to the rotation speed N2 of the third sun gear 301 is greater than P, and the rotation directions of the first sun gear 101 and the third sun gear 301 are both positive, it may cause the rotation direction of the rotation speed N6 of the output part 10 to be reversed. At this time, the vehicle suddenly reverses, and serious accidents are extremely likely to occur. To prevent this situation from happening, a one-way stopper 11 is set on the same-speed connecting body jointly connected by the first planet carrier 102, the second planet carrier 202, the third ring gear 303 and the fourth ring gear 403, so as to limit the rotation direction of the rotation speed N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303 and the fourth ring gear 403 to be only positive and not negative. In this way, it is ensured that the rotation direction of the rotation speed N6 of the output part 10 is always positive. Therefore, when this dangerous condition occurs, since the one-way stopper 11 restricts the rotation direction of the rotation speed N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303 and the fourth ring gear 403 to be only positive and not negative, at this time, the first driving part and the second driving part will drag each other, and the ratio of the magnitude of the rotation speed N1 of the first sun gear 101 to the rotation speed N2 of the third sun gear 301 is always equal to P, and the rotation speed N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303 and the fourth ring gear 403 is equal to 0, so that the rotation direction of the rotation speed N6 of the output part 10 can only be positive, and therefore the vehicle will not suddenly reverse.

[0053] 4. Reverse condition

[0054] See Figure 12, when reversing, the first driving member and the second driving member are activated to accelerate. The first driving member and the second driving member control both the first sun gear 101 and the third sun gear 301 to be in the reverse direction in terms of steering, and control the ratio of the rotational speed N1 of the first sun gear 101 to the rotational speed N2 of the third sun gear 301 to be equal to P in terms of rotational speed. The rotational speed N6 of the output member 10 is gradually accelerated, and the steering is in the reverse direction. Under this condition, the power of the first driving member and the second driving member is coupled together, output with deceleration and torque increase, so that the vehicle accelerates backward.

[0055] In addition to the above normal conditions and dangerous conditions, there are also some emergency conditions that need to be addressed, and the embodiments of the present invention have taken them into consideration and solved them.

[0056] Example: Refer to Figure 10 , when the first driving member fails, the rotational speed of the second driving member driving the third sun gear 301 is N2, and the steering is in the forward direction. The rotational speeds N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403 have a reverse rotation tendency. At this time, the one-way stopper 11 restricts its reverse rotation, so that the rotational speeds N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403 are 0, and the rotational speed N6 of the output member 10 rotates forward. The power of the second driving member is output with deceleration and torque increase through the third planetary gear set 3 and the fourth planetary gear set 4, so that the vehicle can continue to accelerate or decelerate forward.

[0057] Refer to Figure 11 , when the second driving member fails, the rotational speed of the first driving member driving the first sun gear 101 is N1, and the steering is in the forward direction. The rotational speeds N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403 have a reverse rotation tendency. At this time, the one-way stopper 11 restricts its reverse rotation, so that the rotational speeds N3 of the first planet carrier 102, the second planet carrier 202, the third ring gear 303, and the fourth ring gear 403 are 0, and the rotational speed N6 of the output member 10 rotates forward. The power of the first driving member is output with deceleration and torque increase through the first planetary gear set 1, the second planetary gear set 2, and the fourth planetary gear set 4, so that the vehicle can continue to accelerate or decelerate forward.

[0058] It can be seen that when one driving member fails, the other driving member can still drive the vehicle. Although the power performance decreases, the vehicle can be driven to the repair location or a safe location by relying on one driving member, which can greatly improve the reliability of the vehicle.

[0059] The four-planetary-gearset continuously variable transmission mechanism with hierarchical input and its transmission method provided by the embodiments of the present invention have the following advantages:

[0060] 1. The stepless speed change mechanism with hierarchical input of four planetary rows according to the embodiment of the present invention has no power interruption during the speed regulation process, and operates quietly and smoothly. When users use the vehicle, they will have a better experience, which can greatly meet the customer needs in terms of perception and lay a very good foundation for the promotion and use of this product.

[0061] 2. The stepless speed change mechanism with hierarchical input of four planetary rows according to the embodiment of the present invention can achieve large torque at the output end from low speed to high speed. By outputting a large torque, the vehicle has the ability to accelerate quickly when starting, and the large torque can enable the vehicle to climb a greater slope when climbing a hill. The large torque can also meet the vehicle use needs of more people, making the audience of this product larger.

[0062] 3. The stepless speed change mechanism with hierarchical input of four planetary rows according to the embodiment of the present invention can achieve stepless and continuous change of the output speed. The input driving member can work in the high-efficiency range for a long time, improving the working efficiency, achieving a more energy-saving effect in terms of energy use, and making more contributions to energy conservation.

[0063] 4. The stepless speed change mechanism with hierarchical input of four planetary rows according to the embodiment of the present invention has simple and convenient speed regulation. Only by controlling the speeds of the first driving member and the second driving member can stepless and continuous change of the output speed be achieved, thereby reducing the requirements of the vehicle for the control system, making the promotion and use range of this product wider, and ensuring the promotion and popularity of this product to a certain extent.

[0064] 5. The power of the first driving member and the second driving member in the embodiment of the present invention is coupled to drive the vehicle to travel. When one of the driving members fails, the other driving member can still continue to drive the vehicle, ensuring that when the vehicle owner uses the car, even if one driving member fails, the vehicle owner can still rely on the other driving member to drive the car and drive the car to the repair location in time, avoiding the occurrence of the need to call a tow truck and better taking care of the vehicle use experience of the vehicle owner.

[0065] 6. Compared with the traditional driving method of a single driving member, using the product according to the embodiment of the present invention can not only adopt a dual driving member for driving, but also select a driving member with a smaller volume and a lower speed for adaptation. The small-volume driving member is more conducive to the layout design of the driving member in the vehicle body, more convenient for the aesthetic design of the vehicle body shape in the later stage, and using a smaller driving member can save costs.

[0066] 7. The stepless speed change mechanism with hierarchical input of four planetary rows according to the embodiment of the present invention has a high transmission efficiency. Under the same working conditions, a motor with a lower power and a lower speed can be selected as the driving member. Compared with a high-power battery, a small-power battery can better prevent the occurrence of battery overheating, and indirectly improves the use safety of the battery through the embodiment of the present invention.

[0067] 8. The four planetary row continuously variable transmission mechanism with hierarchical input in the embodiment of the present invention adopts four planetary row transmissions, which increases the transmission ratio and further increases the torque. It can be applied to heavy-duty vehicles such as trucks, muck trucks, and buses with larger loads, further broadening the scope of application of the embodiment of the present invention.

[0068] 9. The connection ends of the input end and the output end of the four planetary row continuously variable transmission mechanism with hierarchical input in the embodiment of the present invention are respectively arranged at both ends thereof, avoiding the situation that the input end and the output end affect each other during operation, thereby reducing the overall failure rate.

[0069] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that those skilled in the art may make to some parts thereof all reflect the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A speed change method for a four - planetary - row continuously variable transmission mechanism with hierarchical input, characterized in that, The stepless speed change mechanism of four planetary trains with hierarchical input includes a first planetary train (1), a second planetary train (2), a third planetary train (3) and a fourth planetary train (4). The first sun gear (101) on the first planetary train (1) is connected to a transmission stage (5). The transmission stage (5) includes a transmission gear A (501) and a transmission gear B (502). The transmission gear A (501) and the transmission gear B (502) are meshed by external teeth. The first ring gear (103) on the first planetary train (1) is connected to the second sun gear (201) on the second planetary train (2) through a first connecting shaft (8). The second ring gear (203) on the second planetary train (2) is connected to the third planetary carrier (302) on the third planetary train (3). The third planetary carrier (302) on the third planetary train (3) is connected to the fourth sun gear (401) on the fourth planetary train (4) through a second connecting shaft (9). An output component (10) is connected to the fourth planetary carrier (402) on the fourth planetary train (4). The first planetary carrier (102) on the first planetary train (1), the second planetary carrier (202) on the second planetary train (2), the third ring gear (303) on the third planetary train (3) and the fourth ring gear (403) on the fourth planetary train (4) are all connected to a same-rotation-speed connecting body. A one-way stopper (11) is arranged on the same-rotation-speed connecting body. The first sun gear (101) on the first planetary train (1) is connected to the transmission gear A (501) through a transmission shaft (12). The transmission gear B (502) is connected to a first driving member through a first input shaft (6). The third sun gear (301) on the third planetary train (3) is connected to a second driving member through a second input shaft (7) that sequentially passes through the second sun gear (201), the first connecting shaft (8), the first sun gear (101), the transmission shaft (12) and the transmission gear A (501); The second sun gear (201), the first connecting shaft (8), the first sun gear (101), the transmission shaft (12) and the transmission gear A (501) are all of a through-hollow structure; The one-way stopper (11) is used to limit the rotation directions of the first planetary carrier (102), the second planetary carrier (202), the third ring gear (303) and the fourth ring gear (403); The first driving member and the first sun gear (101) are connected through the first input shaft (6), the transmission stage (5) and the transmission shaft (12), so that the rotational speed of the first driving member and the rotational speed of the first sun gear (101) are in a proportional relationship according to the transmission ratio of the transmission stage (5); the second driving member and the third sun gear (301) are connected through the second input shaft (7), so that the rotational speed of the second driving member is the same as the rotational speed of the third sun gear (301); the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) are all connected to the same-rotational-speed connecting body, so that the rotational speeds of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) are the same; the first ring gear (103) and the second sun gear (201) are connected through the first connecting shaft (8), so that the rotational speed of the first ring gear (103) is the same as the rotational speed of the second sun gear (201); the second ring gear (203) is connected to the third planet carrier (302), and the third planet carrier (302) is connected to the fourth sun gear (401) through the second connecting shaft (9), so that the rotational speeds of the second ring gear (203), the third planet carrier (302) and the fourth sun gear (401) are the same; the fourth planet carrier (402) is connected to the output member (10), so that the rotational speed of the fourth planet carrier (402) is the same as the rotational speed of the output member (10).

2. The speed change method of the four planetary gear trains continuously variable transmission mechanism with hierarchical input according to claim 1, characterized in that, Settings: The rotational speed of the first sun gear (101) is N1, the transmission ratio of the transmission stage (5) is i, the rotational speed of the first driving member is N1×i, the rotational speeds of the second driving member and the third sun gear (301) are N2, the rotational speeds of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) are N3, the rotational speeds of the first ring gear (103) and the second sun gear (201) are N4, the rotational speeds of the second ring gear (203), the third planet carrier (302) and the fourth sun gear (401) are N5, and the rotational speeds of the fourth planet carrier (402) and the output member (10) are N6; when any two of the values of N1, N2, N3, N4, N5, and N6 are determined, the other four values can be calculated through the proportional relationship of the line segments in the vector diagram; by driving the first driving member and the second driving member to adjust and control the rotational speed N1 of the first sun gear (101) and the rotational speed N2 of the third sun gear (301), continuous stepless change of the rotational speed N6 of the output member (10) is achieved. Among them, when the rotational speed N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) is 0, the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) is set as P; by driving the first driving member and the second driving member to adjust and control the rotational speed N1 of the first sun gear (101) and the rotational speed N2 of the third sun gear (301), the output states of the output member (10) include state A, state B, state C, state D, and state E.

3. The speed change method of the four planetary gear trains continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, In state A, the rotational speed N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) is 0, the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) controlled by the first driving member and the second driving member is P, and the rotation directions are both positive, so that the rotation direction of the rotational speed N6 of the output member (10) is positive. At this time, the transmission ratio is in the maximum state.

4. The speed change method of the four planetary gear row continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, In state B, the rotational speed N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) is not 0, the rotation direction is positive, the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) controlled by the first driving member and the second driving member is less than P, and the rotation directions are both positive, so that the rotation direction of the rotational speed N6 of the output member (10) is positive.

5. The speed change method of the four planetary row continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, In the state C, the rotational speeds N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303), and the fourth ring gear (403) are not zero, and the rotation directions are reverse. The first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) to be greater than P, and the rotation directions are both forward. At this time, the rotation direction of the rotational speed N6 of the output member (10) is reverse. To avoid the situation where the rotation direction of the rotational speed N6 of the output member (10) is reverse, a one-way stopper (11) is provided on the same-speed connection body connecting the first planet carrier (102), the second planet carrier (202), the third ring gear (303), and the fourth ring gear (403). The one-way stopper (11) restricts the rotation direction of the rotational speed N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303), and the fourth ring gear (403) to be only forward and not reverse, so that the rotation direction of the rotational speed N6 of the output member (10) is always forward.

6. The speed change method of the four planetary row continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, In the state D, the first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) to be 1, and the rotation directions are both forward, making the rotational speed N6 of the output member (10) equal in magnitude to the rotational speeds N1 of the first sun gear (101) and N2 of the third sun gear (301), and the rotation directions are both forward. At this time, the transmission ratio is 1.

7. The speed change method of the four planetary gear row continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, In the state E, the first driving member and the second driving member control the ratio of the rotational speed N1 of the first sun gear (101) to the rotational speed N2 of the third sun gear (301) to be less than 1, and the rotation directions are both forward, making the rotational speed N6 of the output member (10) greater than the rotational speeds N1 of the first sun gear (101) and N2 of the third sun gear (301), and the rotation direction is forward.

8. The speed change method of the four planetary row continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, When the first driving member fails, the second driving member drives the third sun gear (301) at a rotational speed of N2, and the rotation direction is forward. The rotational speeds N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303), and the fourth ring gear (403) have a reverse rotation tendency. At this time, the one-way stopper (11) restricts its reverse rotation, making the rotational speeds N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303), and the fourth ring gear (403) zero. The rotational speed N6 of the output member (10) rotates forward, and the power of the second driving member is output through the third planetary gear set (3) and the fourth planetary gear set (4) after decelerating and increasing torque.

9. The speed change method of the four planetary gear trains continuously variable transmission mechanism with hierarchical input according to claim 2, characterized in that, When the second driving member fails, the rotational speed of the first sun gear (101) driven by the first driving member is N1, and the rotation direction is forward. The rotational speeds N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) tend to reverse. At this time, the one-way stopper (11) restricts their reverse rotation, so that the rotational speeds N3 of the first planet carrier (102), the second planet carrier (202), the third ring gear (303) and the fourth ring gear (403) are 0, the rotational speed N6 of the output member (10) rotates forward, and the power of the first driving member is output through the first planetary gear set (1), the second planetary gear set (2) and the fourth planetary gear set (4) after deceleration and torque increase.

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