Single-sided Graded Transmission Four-planet-row Continuously Variable Transmission Mechanism and Its Variable Speed Method

Abstract

The present invention discloses a four-planetary-row continuously variable transmission mechanism with unilateral stepped transmission and its speed change method, belonging 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 third sun gear on the third 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 planetary carrier on the third planetary row. The third planetary 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 planetary carrier. A transmission stage is additionally provided between the first planetary row of the four-planetary-row continuously variable transmission mechanism with unilateral stepped transmission of the present invention and the first driving member, and the transmission ratio provided by the transmission stage broadens the power selection range of the first driving member.

Description

Technical Field

[0001] The present invention relates to the technical field of continuously variable transmissions, and particularly relates to a four planetary gear row continuously variable transmission mechanism with unilateral stepped transmission and a speed change method thereof. 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. 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 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, to expand the transmission ratio range, a large number of gears need to be set, resulting in a slow shift process and complex operation, making many large truck 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 gear row continuously variable transmission mechanism with unilateral stepped transmission and a speed change method thereof.

[0004] To achieve the above object, the technical solution of the present invention is a four-planetary-row continuously variable transmission mechanism with unilateral stepped transmission, including a first planetary row, a second planetary row, a third planetary row, and a fourth planetary row. The third sun gear on the third 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 by 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 planetary carrier on the third planetary row. The third planetary carrier 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 planetary carrier on the fourth planetary row. The first planetary carrier on the first planetary row, the second planetary 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-speed connecting body. A one-way stopper is provided on the same-speed connecting body. The third sun gear is connected to the transmission gear A through a transmission shaft that sequentially passes through the third planetary carrier, the second connecting shaft, the fourth sun gear, the fourth planetary carrier, and the output component. The transmission gear B is connected to a second driving member through a second input shaft. The first sun gear on the first planetary row is connected to a first driving member through a first input shaft that sequentially passes through the first connecting shaft, the second sun gear, the third sun gear, the transmission shaft, and the transmission gear A.

[0005] As a further description of the present invention, the first connecting shaft, the second sun gear, the third sun gear, the third planetary carrier, the second connecting shaft, the fourth sun gear, the fourth planetary carrier, the output component, 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 planetary carrier, the second planetary carrier, the third ring gear, and the fourth ring gear.

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

[0008] As a further description of the present invention, it is set that: the rotational speeds of the first driving member and the first sun gear are N1; the rotational speed of the third sun gear is N2, the transmission ratio of the transmission stage is i, the rotational speed of the second driving member is N2×i, 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 to 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 rotational directions are both positive, so that the rotational 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 rotational 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 rotational directions are both positive, so that the rotational 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 rotational 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 rotational directions are both positive. At this time, the rotational direction of the rotational speed N6 of the output member is reverse. In order to avoid the situation where the rotational direction of the rotational speed N6 of the output member is reverse, a one-way stopper is provided on the same-rotational-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 rotational 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 rotational 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 rotational directions are both positive, so that the rotational speed N6 of the output member is equal in magnitude to the rotational speeds N1 of the first sun gear and N2 of the third sun gear, and the rotational 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 rotational 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 rotational 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 to rotate at a speed of N2 in the forward direction. The first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear have a tendency to rotate in the reverse direction. 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 to rotate at a speed of N1 in the forward direction. The first planet carrier, the second planet carrier, the third ring gear, and the fourth ring gear have a tendency to rotate in the reverse direction. 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 unilateral step-by-step transmission four-planetary-gear continuously variable transmission mechanism and its variable speed 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 variable speed 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 second input shaft and the transmission shaft in the unilateral step-by-step transmission four-planetary-gear continuously variable transmission mechanism of the present invention. By changing the tooth number ratio of the transmission gear A and the transmission gear B, the purpose of changing the transmission ratio between the second driving member and the third sun gear is achieved. Therefore, on the premise of achieving the same usage effect, the transmission ratio provided by the transmission stage broadens the power selection range of the second driving member. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the unilateral step-by-step transmission four-planetary-gear continuously variable transmission mechanism 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 of the combination 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;

[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 and the rotation directions are both positive;

[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 and the rotation directions are both positive;

[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 third sun gear rotates in the positive direction when the first driving member fails in the embodiment of the present invention;

[0027] Figure 11 It is a rotational speed vector diagram when the first driving member rotates in the positive direction when the second driving member fails in 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 the 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, we need to explain the purpose of applying for the embodiments of the present invention. We aim to solve the problems of inherent shift shock and power interruption 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 very large number of gears need to be set, resulting in a slow shift process and complex operation, which is the reason why many truck drivers are reluctant to step on the brakes; the shift process of AMT transmissions relies on complex control strategies, making it difficult to grasp the accurate shift 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 unilateral step - by - step transmission is proposed to solve the existing problems.

[0032] The following specifically describes the embodiments of the present invention with reference to the accompanying drawings. First, let's introduce the specific structure of the embodiments of the present invention.

[0033] See Figure 1, a four-planetary-row continuously variable transmission mechanism with unilateral stepped transmission, comprising a first planetary row 1, a second planetary row 2, a third planetary row 3 and a fourth planetary row 4. The third sun gear 301 on the third planetary row 3 is connected to a transmission stage 5. The transmission stage 5 includes a transmission gear A501 and a transmission gear B502, and the transmission gear A501 and the transmission gear B502 are meshed through 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 planetary carrier 302 on the third planetary row 3. The third planetary 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 planetary carrier 402 on the fourth planetary row 4. The first planetary carrier 102 on the first planetary row 1, the second planetary 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 a same-speed connecting body. A one-way stopper 11 is arranged on the same-speed connecting body. The third sun gear 301 on the third planetary row 3 is connected to the transmission gear A501 through a transmission shaft 12 that sequentially passes through the third planetary carrier 302, the second connecting shaft 9, the fourth sun gear 401, the fourth planetary carrier 402 and the output component 10. The transmission gear B502 is connected to a second driving member through a second input shaft 7. The first sun gear 101 on the first planetary row 1 is connected to a first driving member through a first input shaft 6 that sequentially passes through the first connecting shaft 8, the second sun gear 201, the third sun gear 301, the transmission shaft 12 and the transmission gear A501.

[0034] See Figure 1 , the first planetary row 1 includes a first sun gear 101, a first planetary carrier 102 and a first ring gear 103. The second planetary row 2 includes a second sun gear 201, a second planetary carrier 202 and a second ring gear 203. The third planetary row 3 includes a third sun gear 301, a third planetary carrier 302 and a third ring gear 303. The fourth planetary row 4 includes a fourth sun gear 401, a fourth planetary carrier 402 and a fourth ring gear 403. In practical applications, the first connecting shaft 8, the second sun gear 201, the third sun gear 301, the third planetary carrier 302, the second connecting shaft 9, the fourth sun gear 401, the fourth planetary carrier 402, the output component 10, the transmission shaft 12 and the transmission gear A501 are all through hollow structures. 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.

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

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

[0037] According to the basic principle of planetary gears, if 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 third sun gear 301 is N2, the transmission ratio of transmission stage 5 is i, and the rotational speed of the second driving member is N2×i; the rotational speed of the first driving member is the same as that of the first sun gear 101, which is set as N1; 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, which is set as N3; the rotational speeds of the first ring gear 103 and the second sun gear 201 are the same, which is set 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, which is set as N5; the rotational speed of the fourth planet carrier 402 is the same as that of the output member 10, which is set 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 The length of the line segment in the figure 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] By 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 Figure 3 shown is obtained.

[0041] See Figure 3 , when any two 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 of the first driving member is determined and the rotational speed N2×i 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 of the first driving member and the rotational speed N2×i 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, the continuous stepless change 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 unilateral stepped transmission in the embodiment of the present invention will be described in combination with specific working conditions.

[0043] 1. Starting condition

[0044] SeeFigure 3 When starting, the vehicle 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 part 10 is gradually accelerated, and the steering is positive. In this condition, the power of the first driving part and the second driving part is coupled together, and the speed is reduced while the torque is increased for output, so that the vehicle accelerates forward.

[0045] 2. Acceleration and deceleration 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 speed N1 of the first sun gear 101 and the rotational speed N2 of the third sun gear 301 and the degree of acceleration and deceleration, the first driving part and the second driving part can achieve a gradual increase or decrease in the rotational speed N6 of the output part 10, with the steering being positive, so that the vehicle accelerates or decelerates forward.

[0047] In addition, as Figure 8 shown, the speed regulation method 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 part 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 101 by the first driving part to adjust the magnitude of the rotational speed N6 of the output part 10. Therefore, in the process of accelerating or decelerating the rotational speed N6 of the output part 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 different, and the control system controls according to the current working condition. 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 condition

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

[0050] See also Figure 7 If the vehicle needs to reach a higher speed after reaching the aforementioned maximum speed, the first drive element's rotational speed N1 can be reduced, which will also reduce the rotational speed N1 of the first sun gear 101. The second drive element maintains the rotational speed N2 of the third sun gear 301 at the maximum speed, allowing the rotational speed N6 of the output element 10 to continue to increase. The maximum vehicle speed is determined by the rotational speed N6 of the output element 10, which can be set by controlling the rotational speeds N1 of the first drive element and N2 of the second drive element × i. Therefore, by simply selecting a second drive element with a lower rotational speed, a very high output speed can be achieved, further reducing the power requirements of the drive element.

[0051] Regarding the above-mentioned starting conditions and acceleration and deceleration conditions, there is a dangerous condition that needs to be considered and how to avoid it.

[0052] Example: See Figure 5 When the speed control of the first and second drive members is inaccurate or fails, the ratio of the speed N1 of the first sun gear 101 to the speed N2 of the third sun gear 301 may be greater than P. If both the first and third sun gears 101 and 301 are rotating in the forward direction, the speed N6 of the output member 10 may steer in the reverse direction. This could cause the vehicle to suddenly roll back, potentially leading to a serious accident. To prevent this, a one-way stopper 11 is provided on the speed-matching connector connecting the first planetary carrier 102, the second planetary carrier 202, the third ring gear 303, and the fourth ring gear 403. This restricts the speed N3 of the first planetary carrier 102, the second planetary carrier 202, the third ring gear 303, and the fourth ring gear 403 to only forward and not reverse. This ensures that the speed N6 of the output member 10 always steers in the forward direction. Therefore, when this dangerous working condition occurs, since the one-way stopper 11 limits the rotational speed N3 of the first planetary carrier 102, the second planetary carrier 202, the third ring gear 303 and the fourth ring gear 403 to only forward and not reverse, the first driving member and the second driving member will drag each other. 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 always equal to P, and the rotational speed N3 of the first planetary carrier 102, the second planetary carrier 202, the third ring gear 303 and the fourth ring gear 403 is equal to 0, so that the rotational speed N6 of the output component 10 can only turn in the forward direction, so the vehicle will not suddenly reverse.

[0053] 4. Reversing conditions

[0054] See also 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. In this working condition, the power of the first driving member and the second driving member is coupled together, decelerated and torque-increased for output, so that the vehicle accelerates and reverses.

[0055] In addition to the above normal working conditions and dangerous working conditions, there are also some emergency working conditions that need to be dealt with, and all of these are considered and solved in the embodiments of the present invention.

[0056] Example: Refer to Figure 10 , when the first driving member fails, the rotational speed of the third sun gear 301 driven by the second driving member 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 trend. 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 in the forward direction, and the power of the second driving member is decelerated and torque-increased through the third planetary gear set 3 and the fourth planetary gear set 4 for output, so that the vehicle can continue to accelerate or decelerate and move forward.

[0057] Refer to Figure 11 , 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 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 trend. 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 in the forward direction, and the power of the first driving member is decelerated and torque-increased through the first planetary gear set 1, the second planetary gear set 2, and the fourth planetary gear set 4 for output, so that the vehicle can continue to accelerate or decelerate and move forward.

[0058] It can be seen that when one driving member fails, the other driving member can still drive the vehicle to travel. 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 single-sided hierarchical transmission four-planetary-gear continuously variable transmission mechanism and its transmission method provided by the embodiments of the present invention have the following advantages:

[0060] 1. The stepless speed change mechanism with single-sided stepped transmission 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 stably. When users use the vehicle, they will have a better experience, which can greatly meet the customer needs in terms of senses and lay a very good foundation for the promotion and use of this product.

[0061] 2. The stepless speed change mechanism with single-sided stepped transmission 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 large torque, the vehicle has the ability to accelerate quickly when starting, and the large torque enables 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 single-sided stepped transmission 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 part can work in the high-efficiency range for a long time, improving the working efficiency, achieving a more energy-saving effect in the use of energy, and making more contributions to energy conservation.

[0063] 4. The stepless speed change mechanism with single-sided stepped transmission 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 part and the second driving part 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. In the embodiment of the present invention, the power of the first driving part and the second driving part is coupled to drive the vehicle to travel. When one of the driving parts fails, the other driving part can still continue to drive the vehicle, ensuring that when the vehicle owner uses the car, even if one driving part fails, the vehicle owner can still rely on the other driving part 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 part, using the product according to the embodiment of the present invention can not only adopt dual driving parts for driving, but also select driving parts with smaller volume and lower speed for adaptation. The driving parts with smaller volume are more conducive to the layout design of the driving parts in the vehicle body, more convenient for the aesthetic design of the vehicle body shape in the later stage, and the use of smaller driving parts can save costs.

[0066] 7. The stepless speed change mechanism with unilateral stepped transmission of 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 part. Compared with a high-power battery, a low-power battery can better prevent the occurrence of battery overheating, thereby indirectly improving the safety of battery use through the embodiment of the present invention.

[0067] 8. The stepless speed change mechanism with unilateral stepped transmission of the embodiment of the present invention adopts a four-planetary row transmission, 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 a greater load, further broadening the scope of application of the embodiment of the present invention.

[0068] 9. The connection ends of the first driving part, the second driving part, and the output component of the stepless speed change mechanism with unilateral stepped transmission of the embodiment of the present invention are all arranged at one end of the stepless speed change mechanism, so that the input and output of power are both at one end of the stepless speed change mechanism. Moreover, the first input shaft passes through the second input shaft and the second driving part to be connected to the first driving part. Such a design can greatly improve the utilization rate of space and make the layout and space utilization rate of the entire power equipment more reasonable.

[0069] 10. A transmission stage is arranged between the second input shaft and the transmission shaft of the stepless speed change mechanism with unilateral stepped transmission of the embodiment of the present invention. By changing the tooth number ratio of the transmission gear A and the transmission gear B, the purpose of changing the transmission ratio between the second driving part and the third sun gear is achieved. 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 second driving part.

[0070] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that may be made to some parts by those skilled in the art of the present technology all reflect the principles of the present invention and are within the protection scope of the present invention.

Claims

1. A speed change method for a four planetary gear train continuously variable transmission mechanism with unilateral stepped transmission, characterized in that, The four planetary row continuously variable transmission mechanism with unilateral hierarchical transmission includes a first planetary row (1), a second planetary row (2), a third planetary row (3) and a fourth planetary row (4). The third sun gear (301) on the third planetary row (3) 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 through 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 planetary carrier (302) on the third planetary row (3). The third planetary carrier (302) 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 planetary carrier (402) on the fourth planetary row (4). The first planetary carrier (102) on the first planetary row (1), the second planetary 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 a same-speed connecting body. A one-way stopper (11) is arranged on the same-speed connecting body. The third sun gear (301) is connected to the transmission gear A (501) through a transmission shaft (12) sequentially passing through the third planetary carrier (302), the second connecting shaft (9), the fourth sun gear (401), the fourth planetary carrier (402) and the output component (10). The transmission gear B (502) is connected to a second driving member through a second input shaft (7). The first sun gear (101) on the first planetary row (1) is connected to a first driving member through a first input shaft (6) sequentially passing through the first connecting shaft (8), the second sun gear (201), the third sun gear (301), the transmission shaft (12) and the transmission gear A (501); The first connecting shaft (8), the second sun gear (201), the third sun gear (301), the third planetary carrier (302), the second connecting shaft (9), the fourth sun gear (401), the fourth planetary carrier (402), the output component (10), 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 is connected to the first sun gear (101) through the first input shaft (6), so that the rotational speed of the first driving member is the same as that of the first sun gear (101); the second driving member and the third sun gear (301) are connected through the second input shaft (7), the transmission stage (5), and the transmission shaft (12), so that the rotational speed of the second driving member and the rotational speed of the third sun gear (301) are in a proportional relationship according to the transmission ratio of the transmission stage (5); 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-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 that 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 that of the output member (10).

2. The speed change method of the four planetary row continuously variable transmission mechanism with unilateral hierarchical transmission according to claim 1, characterized in that, Settings: The rotational speed of the first driving member and the rotational speed of the first sun gear (101) are N1; the rotational speed of the third sun gear (301) is N2, the transmission ratio of the transmission stage (5) is i, the rotational speed of the second driving member is N2×i, 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 row continuously variable transmission mechanism with unilateral hierarchical transmission 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, making the rotation direction of the rotational speed N6 of the output member (10) positive. At this time, it is in the state of the maximum transmission ratio.

4. The speed change method of the four planetary row continuously variable transmission mechanism with unilateral hierarchical transmission 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, and 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, making the rotation direction of the rotational speed N6 of the output member (10) positive.

5. The speed change method of the four planetary row continuously variable transmission mechanism with unilateral hierarchical transmission 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 connecting body connected to 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 unilateral hierarchical transmission 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, so that the rotational speed N6 of the output member (10) is 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 stepless speed change mechanism with four planetary rows of unilateral stepped transmission 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, so that the rotational speed N6 of the output member (10) is 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 unilateral hierarchical transmission 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, 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 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 row continuously variable transmission mechanism with unilateral stepped transmission 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 direction of rotation 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, 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 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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