Large-speed-ratio speed change and differential mechanism based on planetary gear train

Abstract

The speed change and differential mechanism based on the planetary gear train is mainly composed of three stages of planet rows, the first-stage planet row is of a traditional NGW structure, and a sun gear of the first-stage planet row serves as power input; the second-level planet row and the third-level planet row are duplex planet rows arranged side by side, a gear ring of the second-level planet row and a sun gear of the third-level planet row are the same part, a planet carrier of the second-level planet row serves as an output end 1, and a gear ring of the third-level planet row serves as an output end 2. Through the combination mode of the single-planet-carrier gear train and the double-planet-carrier gear train, the speed ratio of the speed reducer can be increased, meanwhile, the functions of the two output ends are achieved under the condition that a differential mechanism is omitted, the two output ends can achieve the same speed or differential speed, and therefore the weight and the size of the speed reducer are reduced; and the high-speed and light-weight requirements of an electric drive system can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of speed reducers, and particularly to a large speed ratio variable speed and differential mechanism based on a planetary gear train. Background Art

[0002] A planetary gear speed reducer is a precision speed reducer, which mainly realizes the speed reduction transmission between the input shaft and the output shaft through the meshing transmission of planetary gears. Due to its characteristics such as high precision, high efficiency, and high load-bearing capacity, the planetary gear speed reducer is widely used in various industries.

[0003] The existing electric drive planetary gear speed reducer generally has a reduction ratio difficult to exceed 11 because it adopts the traditional NW architecture form. A low reduction ratio means it is difficult to match a high-speed motor with the NW configuration planetary gear speed reducer; at the same time, in order to realize the differential function of two output ends in the NW configuration speed reducer, a special differential mechanism generally needs to be integrated in the transmission. The speed reducer with a special differential is not only heavy but also large in volume, and it is difficult to meet the requirements of high speed and light weight of the electric drive system. Summary of the Invention

[0004] The purpose of the present invention is to provide a large speed ratio variable speed and differential mechanism based on a planetary gear train to solve the problems raised in the above background art.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A large speed ratio variable speed and differential mechanism based on a planetary gear train, including a housing. A first-stage ring gear fixed to the housing is provided inside the housing. A first-stage planetary gear is meshed with the first-stage ring gear. A first-stage sun gear is meshed with the first-stage planetary gear. A first-second-stage sun gear is meshed with a first-second-stage planetary gear. A first-second-stage planetary gear is meshed with a first-stage internal and external gear ring. A first-third-stage planetary gear is meshed with the first-stage internal and external gear ring. A first-third-stage ring gear is sleeved on the first-stage internal and external gear ring, and the first-third-stage ring gear is meshed with the first-third-stage planetary gear.

[0006] As a further technical solution of the present invention, a first-stage planetary carrier is rotatably connected inside the housing. The first-stage planetary gear is rotatably connected to the first-stage planetary carrier, and the first-stage planetary carrier is fixedly connected to the first-second-stage sun gear.

[0007] As a further technical solution of the present invention, a first-second-stage planetary carrier is rotatably connected inside the housing, and the first-second-stage planetary gear is rotatably connected to the first-second-stage planetary carrier.

[0008] As a further technical solution of the present invention, a first-third-stage planetary carrier is fixedly connected inside the housing, and the first-third-stage planetary gear is rotatably connected to the first-third-stage planetary carrier.

[0009] As a further technical solution of the present invention, mounting plates are fixedly connected to the outer walls on both sides of the housing.

[0010] As a further technical solution of the present invention, mounting holes are formed in the outer wall on one side of the mounting plate.

[0011] As a further technical solution of the present invention, a bearing is fixedly connected inside the housing.

[0012] As a further technical solution of the present invention, a coupling is rotatably connected to the bearing, and the coupling is fixedly connected to the first-stage sun gear.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: By combining a single planetary carrier gear train and a double planetary carrier gear train, while increasing the reduction ratio of the reducer, the functions of two output ends are achieved without a differential, and the two output ends can rotate at the same speed or different speeds, thereby reducing the weight and volume of the reducer, and meeting the requirements of high-speed and lightweight of the electric drive system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is a schematic three-dimensional structure diagram of the whole of the present invention; Figure 2 It is a schematic transmission structure diagram of Embodiment 1 of the present invention; Figure 3 It is a schematic transmission structure diagram of Embodiment 2 of the present invention.

[0016] In the figure: 11, the first-stage sun gear; 12, the first-stage planetary gear; 13, the first-stage planetary carrier; 14, the first-stage ring gear; 15, the second-stage sun gear; 16, the second-stage planetary carrier; 17, the second-stage planetary gear; 18, the first-stage internal and external tooth ring; 19, the first-third planetary gear; 20, the first-third planetary carrier; 21, the first-third ring gear; 31, the second-stage sun gear; 32, the second-stage planetary gear; 33, the second-stage planetary carrier; 34, the second-stage ring gear; 35, the second-second sun gear; 36, the second-second planetary carrier; 37, the second-second planetary gear; 38, the second-stage internal and external tooth ring; 39, the second-third planetary gear; 40, the second-third planetary carrier; 41, the second-third ring gear; 3, the housing; 4, the mounting plate; 5, the mounting hole; 6, the bearing; 7, the coupling. DETAILED DESCRIPTION OF THE INVENTION

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] Please refer to the attached Figure 1 - attached Figure 3 , a technical solution provided by the present invention: Embodiment

[0019] A large speed ratio variable speed and differential mechanism based on a planetary gear train, including a housing 3. Inside the housing 3, a first-stage ring gear 14 is provided. A first-stage planet gear 12 is meshed and connected to the first-stage ring gear 14. A first-stage sun gear 11 is meshed and connected to the first-stage planet gear 12. A second-stage sun gear 15 is meshed and connected to a second-stage planet gear 17. A first-stage internal and external gear ring 18 is sleeved on the second-stage sun gear 15, and the first-stage internal and external gear ring 18 is meshed and connected to the second-stage planet gear 17 and a third-stage planet gear 19. ， A third-stage ring gear 21 is sleeved on the first internal and external gear ring 18, and the third-stage ring gear 21 is meshed and connected to the third-stage planet gear 19; the first-stage ring gear 14 is fixed to the housing 3; the first-stage planet gear 12 is rotatably connected to a first-stage planet carrier 13, and the first-stage planet carrier 13 is fixedly connected to the second-stage sun gear 15; the second-stage planet gear 17 is rotatably connected to a second-stage planet carrier 16, and the second-stage planet carrier 16 serves as output 1; a third-stage planet carrier 20 is fixedly connected inside the housing 3, and the third-stage planet gear 19 is rotatably connected to the third-stage planet carrier 20; the third-stage ring gear 21 serves as output 2; mounting plates 4 are fixedly connected to the outer walls on both sides of the housing 3; mounting holes 5 are provided on the outer wall of one side of the mounting plate 4, and the mounting plate 4 and the mounting holes 5 are used to mount the housing 3; a bearing 6 is fixedly connected inside the housing 3, and the bearing 6 is used to mount a coupling 7; the coupling 7 is rotatably connected to the bearing 6, and the coupling 7 is fixedly connected to the first-stage sun gear 11, and the coupling 7 is used to connect the motor output end and the first-stage sun gear 11. Embodiment

[0020] A large speed ratio variable speed and differential mechanism based on a planetary gear train, including a housing 3. A second first-stage ring gear 34 is arranged inside the housing 3. A second first-stage planet gear 32 is meshed and connected to the second first-stage ring gear 34. A second first-stage sun gear 31 is meshed and connected to the second first-stage planet gear 32. A second second-stage sun gear 35 is meshed and connected to a second second-stage planet gear 37. A second first-stage internal and external gear ring 38 is sleeved on the second second-stage sun gear 35, and the second first-stage internal and external gear ring 38 is internally meshed with the second second-stage planet gear 37 and externally meshed with a second third-stage planet gear 39. ， A second third-stage ring gear 41 is sleeved on the second first-stage internal and external gear ring 38, and the second third-stage ring gear 41 is meshed and connected to the second third-stage planet gear 39; the second first-stage ring gear 34 is fixed on the housing 3; the second first-stage planet gear 32 is rotatably connected to a second first-stage planet carrier 33, and the second first-stage planet carrier 33 is fixedly connected to the second second-stage sun gear 15; the second second-stage planet gear 37 is rotatably connected to a second second-stage planet carrier 36, and the second second-stage planet carrier 36 serves as output 1; the second first-stage ring gear 34 is fixedly connected to a second third-stage planet carrier 40, and the second third-stage planet carrier 40 is rotatably connected to the first third-stage planet gear 39; the second third-stage ring gear 41 serves as output 2; mounting plates 4 are fixedly connected to the outer walls on both sides of the housing 3; mounting holes 5 are formed in the outer wall of one side of the mounting plate 4, and the mounting plate 4 and the mounting holes 5 are used for mounting the housing 3; a bearing 6 is fixedly connected inside the housing 3, and the bearing 6 is used for mounting a coupling 7; the coupling 7 is rotatably connected to the bearing 6, and the coupling 7 is fixedly connected to the second first-stage sun gear 31, and the coupling 7 is used for connecting the motor output end and the second first-stage sun gear 31.

[0021] Working principle: When implementing the first embodiment of the present invention, first install the housing 3 at a designated position through the mounting holes 5 on the mounting plate 4, and then connect the output end of the motor and the first-stage sun gear 11 through the coupling 7 on the bearing 6 as the input. When the first-stage sun gear 11 rotates with the input, the first-stage sun gear 11 drives the first-stage planet gear 12, and the first-stage planet gear 12 drives the first-stage planet carrier 13. Since the first-stage ring gear is fixed to the housing, the rotation speed of the first-stage planet carrier is determined by the rotation speed of the first-stage sun gear; the rotation speed of the second-stage sun gear 15 is the same as that of the first-stage planet carrier 13. The second-stage sun gear 15 drives the second-stage planet gear 17 to rotate, and the second-stage planet gear 17 simultaneously drives the second-stage planet carrier 16 and the first-stage internal and external gear ring 18 to rotate. The first-stage internal and external gear ring 18 drives the third-stage planet gear 19 to rotate, and the third-stage planet gear 19 drives the third-stage ring gear 21 to rotate; since the third-stage planet carrier 20 is fixed, the rotation speed of the third-stage ring gear is determined by the rotation speed of the first-stage internal and external gear ring 18, and the rotation speed of the first-stage internal and external gear ring 18 is jointly determined by the second-stage sun gear 15 and the second-stage planet carrier 16. Therefore, when the first-stage sun gear 11 receives the input, the second-stage planet carrier 16 and the third-stage ring gear 21 will jointly output, and the output rotation speeds of the first-stage planet carrier 12 and the third-stage ring gear 21 are interlocked with each other.Assume that the number of teeth Z1 of the first-stage sun gear 11 is 80, the number of teeth Z14 of the first-stage ring gear 14 is 120, the number of teeth Z15 of the second-stage sun gear 15 is 40, the internal number of teeth Z191 of the first-stage internal and external gear ring 19 is 80 and its external number of teeth Z192 is 90, and the number of teeth Z21 of the third-stage ring gear 21 is 135; the speed ratio of the first planetary gear set i1 = 120 / 80 = 1.5. The motor torque T0 is input to the first-stage sun gear 11 through the coupling 7. After being amplified by the first planetary gear set, the torque T15 input to the second-stage sun gear 15 by the first planetary carrier 13 is T15=(1 + i1)*T0 = 2.5T0; looking only at the second planetary gear train, its speed ratio i2 = 80 / 40 = 2, and looking only at the third planetary gear train, its speed ratio i3 = 135 / 90 = 1.5; at the same time, since the input torque obtained by the second-stage sun gear 15 as the input end of the second planetary gear set is T15 = 2.5T0, then the output torque T16 of the first and second planetary carrier 16 as the output end 1 is T16=-(1 + i2)*2.5T0 = -7.5T0, and the external tooth torque of the first-stage internal and external gear ring 18 is T182=-i2*T15 = -5T0. The output torque of the third-stage ring gear 21 as the output end 2 is T21 = i3*T182 = -7.5T0. From the above conclusions, it can be seen that the output torque of the first and second planetary carrier 16 at the output end 1 is equal to the output torque of the third-stage ring gear 21, and the sum of the output torques is T16 + T21 = -15T0. Therefore, the speed ratio i of the planetary reduction mechanism designed based on this number of teeth is i = 15T0 / T0 = 15; similarly, the rotation speed formula of the entire planetary structure can be calculated as: n1 - 7.5*(n16 + n21)=0, where n1 is the rotation speed of the first-stage sun gear 11 as the input end, n16 is the rotation speed of the first and second planetary carrier 16 as the output end 1, and n21 is the rotation speed of the third-stage planetary carrier 21 as the output end 2. When the vehicle is driving straight, the rotation speeds of the left and right output ends of the reduction gearbox are the same. At this time, n16 = n21 = n1 / 15; when the vehicle is turning, there will be a speed difference n between the left and right output ends of the reduction gearbox. If the rotation speed n16 of the first and second planetary carrier 16 at the output end 1 is n16 = n1 / 15 - 0.5n, then the rotation speed n21 of the third-stage ring gear at the output end 2 is n21 = n1 / 15 + 0.5n. From the above calculation results, it can be seen that this planetary mechanism can not only achieve a large torque ratio but also output an additional differential function. It can be seen that the reduction ratio of the structure of this application is not calculated by multiplying step by step as in the traditional calculation of the reduction ratio, but by considering this three-stage planetary gear reducer as a whole. At the same time, the traditional planetary reduction mechanism has only one output, while the structure of this application has two outputs, and the two outputs can meet the requirements of the traditional differential function. Through reasonable tooth number matching, the same torque can be obtained at the two output ends at the same time.

[0022] The working principle of the second embodiment is the same as that of the first embodiment. The only difference is that in the second embodiment, the second and third planet carriers 40 are not directly fixed to the housing, but are fixedly connected to the second and first gear rings 34 to achieve fixation.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0024] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-speed ratio speed change and differential mechanism based on a planetary gear system, comprising a housing (3), characterized in that: A first-stage ring gear (14) is arranged in the housing (3); the first-stage ring gear (14) is fixed on the housing (3) and meshingly connected with a first-stage planetary gear (12); the first-stage planetary gear (12) is meshingly connected with a first-stage sun gear (11); the first-stage sun gear (15) is meshingly connected with a first-stage planetary gear (17); the first-stage planetary gear (17) is meshingly connected with a first-stage internal and external gear ring gear (18); the first-stage internal and external gear ring gear (18) is meshingly connected with a first-stage tertiary planetary gear (19); the first-stage internal and external gear ring gear (18) is sleeved with a first-stage tertiary gear ring (21); and the first-stage tertiary gear ring (21) is meshingly connected with the first-stage tertiary planetary gear (19).

2. A large speed ratio speed change and differential mechanism based on a planetary gear system according to claim 1, characterized in that: The first-stage planetary gear (12) is rotatably connected to a first-stage planetary carrier (13), and the first-stage planetary carrier (13) is fixedly connected to a first-stage sun gear (15).

3. A large speed ratio speed change and differential mechanism based on a planetary gear system according to claim 1, characterized in that: The housing (3) is rotatably connected to a first and second planet carrier (16), and the first and second planet wheels (17) are rotatably connected to the first and second planet carrier (16).

4. The large speed ratio transmission and differential mechanism based on a planetary gear system according to claim 1, characterized in that: A first third-stage planet carrier (20) is fixedly connected inside the housing (3), and the first third-stage planet gear (19) is rotatably connected to the first third-stage planet carrier (20).

5. The large speed ratio speed change and differential mechanism based on a planetary gear system according to claim 3, characterized in that: Mounting plates (4) are fixedly connected to the outer walls on both sides of the housing (3).

6. A large speed ratio speed change and differential mechanism based on a planetary gear system according to claim 4, characterized in that: A mounting hole (5) is provided on an outer wall of one side of the mounting plate (4).

7. The large speed ratio speed change and differential mechanism based on a planetary gear system according to claim 1, characterized in that: A bearing (6) is fixedly connected inside the housing (3).

8. The large speed ratio transmission and differential mechanism based on a planetary gear system according to claim 6, characterized in that: A coupling (7) is rotatably connected to the bearing (6), and the coupling (7) is fixedly connected to the first primary sun gear (11).

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