Hollow large-speed-ratio 3K planetary speed reduction type electric drive joint

Abstract

The invention discloses a hollow large-speed-ratio 3K planetary speed reduction type electric drive joint which comprises a shell and further comprises an inner rotor motor, a hollow pipe, a 3K planetary speed reduction mechanism and a power output mechanism which are arranged in the shell. The inner rotor motor comprises a motor stator and a motor rotor arranged in the motor stator; the 3K planetary reduction mechanism comprises a sun wheel shaft, a first planetary gear, a fixed gear ring, a second planetary gear, a planetary carrier and an output gear ring; the sun wheel shaft comprises a main shaft body and a sun wheel arranged on one side of the main shaft body in a coaxial and synchronous rotation mode. The hollow pipe is provided with a second middle hole, one end of the hollow pipe is rotationally connected with the shell, the middle of the hollow pipe penetrates through the sun wheel shaft and the planet carrier, and the other end of the hollow pipe is fixedly connected with a power output mechanism. Wiring arrangement of the electrically-driven joint is facilitated, the reduction ratio is large, the integration degree is high, the envelope size is small, and the torque density is high.

Description

TECHNICAL FIELD

[0001] The present application relates to a robot electric drive joint, in particular to a hollow large speed ratio 3K planetary reduction type electric drive joint. BACKGROUND

[0002] The main technical routes of the electric drive joint for the robot rotary actuator at present are divided into three categories: harmonic reducer electric drive joint, RV reducer electric drive joint and planetary reduction electric drive joint, each has advantages and disadvantages, and the market will coexist for a long time. The planetary reduction electric drive joint has the advantages of strong anti-torque impact capacity, high efficiency, long service life and low manufacturing cost, and the market mainstream planetary reduction electric drive joint adopts 2K-H planetary transmission (NGW type simple planetary transmission and NW type composite planetary transmission belong to 2K-H planetary transmission category), which is usually not hollow. The hollow structure is convenient for wiring arrangement, so the hollow structure is more in line with the market development demand. At the same time, under the requirement of robot application scene, the electric drive joint needs to achieve large torque density, so that the reducer is required to have large reduction ratio. The maximum speed ratio of the existing hollow planetary reducer is small (usually the maximum speed ratio is not higher than 25), which cannot meet the market demand. Some technical documents record that the planetary reduction electric drive joint adopts the technical scheme of setting 3K planetary reduction structure in the motor stator inside the outer rotor frameless torque motor. Although the large speed ratio reduction is realized in the theoretical level, there is no commercialized product to verify the engineering feasibility, and since the 3K planetary reduction structure is arranged in the motor stator inside the outer rotor frameless torque motor, the hollow structure cannot be realized, and it is not conducive to heat dissipation, and the thermal power limits the performance of the joint. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a hollow large speed ratio 3K planetary reduction type electric drive joint, which is beneficial to the wiring arrangement of the electric drive joint, has large reduction ratio, high integration, small envelope size and high torque density.

[0004] The hollow large speed ratio 3K planetary reduction type electric drive joint in the present application comprises a shell, an inner rotor motor, a hollow tube, a 3K planetary reduction mechanism and a power output mechanism arranged in the shell; The inner rotor motor comprises a motor stator and a motor rotor arranged in the motor stator; The 3K planetary reduction mechanism comprises a sun gear shaft, a first planetary gear, a fixed ring gear, a second planetary gear, a planet carrier and an output ring gear; The sun shaft comprises a main shaft body and a sun gear arranged on one side of the main shaft body in a coaxial synchronous rotation manner, the motor rotating shaft has a first middle hole, the first middle hole is sleeved on the main shaft body in a coaxial synchronous rotation manner; the fixed gear ring is fixed in position; the first planetary gear is engaged between the sun gear and the fixed gear ring; the first planetary gear and the second planetary gear are connected in a coaxial synchronous rotation manner and are both rotationally installed on the planet carrier; the second planetary gear is engaged with the output gear ring, the output gear ring is fixedly connected with the power output mechanism, and the power output mechanism is rotationally connected with the shell; The hollow pipe has a second middle hole, one end of the hollow pipe is rotationally connected with the shell, the middle part of the hollow pipe passes through the sun shaft and the planet carrier, and the other end of the hollow pipe is fixedly connected with the power output mechanism.

[0005] Further, the shell comprises a motor half shell and a reducer half shell, the opposite sides of the motor half shell and the reducer half shell are both open structures, and the opposite sides of the motor half shell and the reducer half shell are fixedly connected; the inner rotor motor is arranged in the motor half shell, and the 3K planetary reduction mechanism is arranged in the reducer half shell.

[0006] Further, the motor half shell and the hollow pipe are connected through a first bearing, the motor half shell and the main shaft body are connected through a second bearing, and the reducer half shell and the power output mechanism are connected through a third bearing.

[0007] Further, the sun shaft has a third middle hole, the planet carrier has a fourth middle hole, and the third middle hole and the fourth middle hole are arranged on the outside of the hollow pipe in a coaxial opposite rotation manner.

[0008] Further, the planet carrier is a floating planet carrier. A bearing mounting seat is arranged between the floating planet carrier and the inner rotor motor, the bearing mounting seat comprises an inner seat body, a partition plate and an outer seat body, the inner seat body is arranged on the side of the partition plate along the second middle hole in a radially inward direction, and the outer seat body is arranged on the side of the partition plate along the second middle hole in a radially outward direction. The inner seat body and the main shaft body are connected through a fourth bearing, the outer seat body is fixedly connected with the shell, the fixed gear ring is fixedly connected with the outer seat body, one end of the floating planet carrier close to the motor rotor is sleeved on the inner seat body, the fourth middle hole is in clearance fit with the inner seat body, and one end of the floating planet carrier close to the power output mechanism is suspended.

[0009] Optionally, the planet carrier is a rotating planet carrier. Two ends of the rotating type planet carrier are respectively installed through a fifth bearing and a sixth bearing; One end of the rotating type planet carrier close to the motor rotor is provided with a first extension part, and one end of the rotating type planet carrier close to the power output mechanism is provided with a second extension part; an inner ring of the fifth bearing is sleeved on the main shaft body, and an outer ring of the fifth bearing is sleeved in the first extension part; an inner ring of the sixth bearing is sleeved on the second extension part, and an outer ring of the sixth bearing is sleeveled in the power output mechanism; The fixed gear ring is fixedly connected with the shell.

[0010] Further, the third bearing is a crossed roller bearing, and the crossed roller bearing is axially positioned through a fixed ring and a retainer.

[0011] Further, the first planetary gear and the second planetary gear form a double planetary gear, the double planetary gear is rotatably installed on a planet shaft pin through a planet wheel bearing, and the planet pin is fixedly connected with the planet carrier.

[0012] Further, the motor rotor is a frameless torque motor rotor, the motor rotor comprises a magnetic steel and a rotor punching sheet, a plurality of clamping seats are arranged on one side of the rotor punching sheet radially outward along a first middle hole, the plurality of clamping seats are arranged at intervals in a circumferential direction, a clamping groove is formed between two adjacent clamping seats, and the magnetic steel is arranged in the clamping groove.

[0013] Further, the two sides of each clamping seat are inclined surfaces, the inclined surfaces are inclined from inside to outside along the first middle hole and towards the inside of the clamping groove; an end portion of each clamping seat away from the first middle hole is provided with a limiting corner extending to the inside of the clamping groove towards two sides, a corner of the magnetic steel is provided with a chamfer matched with the shape of the limiting corner; and the inside of each clamping seat is provided with a lightening groove.

[0014] The present application has the following advantages: (1) The inner rotor motor is adopted, compared with the outer rotor motor, the torque response is faster, and the heat dissipation performance is better, meanwhile, the second middle hole of the hollow pipe penetrates along the axial direction, the hollow pipe passes through the sun gear shaft and the planet carrier, a larger hollow size can be realized, and the wiring arrangement of the electric drive joint is facilitated.

[0015] (2) The sun gear shaft of the 3K planetary reduction mechanism of the application extends into the interior of the motor rotor, the inner rotor motor and the power output mechanism are respectively located at different sides of the 3K planetary reduction mechanism, the motor torque is reduced and the torque is increased through the 3K planetary reduction mechanism composed of the sun gear shaft, the first planetary gear, the fixed gear ring, the second planetary gear, the planet carrier and the output gear ring, and then the power is output by the power output mechanism, the 3K planetary reduction mechanism can realize large speed ratio reduction. Moreover, the axial arrangement form of the 3K planetary reduction mechanism and the inner rotor motor reduces the radial size of the joint, compared with the radial arrangement form, the speed reduction ratio of the application is larger under the premise of the same joint diameter, the sun gear shaft of the 3K planetary reduction mechanism extends into the motor rotor, which reduces the axial size of the joint, has high integration degree and small envelope size, and higher torque density can be realized under the same envelope size. When applied to the robot joint, a large speed ratio of 99 can be achieved under the condition that the outer diameter of the joint is Φ125mm and the inner diameter of the hollow tube is Φ10mm, and the highest operating speed of the joint assembly can reach 400rpm, which is much higher than the current market products.

[0016] (3) When the planet carrier of the application is a floating planet carrier, the floating planet carrier of the 3K planetary reduction mechanism is completely floating without bearing support, and the completely floating design can ensure the uniform distribution of the load between the planetary gears; moreover, the bearing mounting seat divides the motor half shell and the reducer half shell into two sealed chambers, so that the inner rotor motor and the gears of the 3K planetary reduction mechanism are respectively located in independent sealed chambers, and the lubricating grease in the interior of the reducer half shell cannot flow into the interior of the motor half shell.

[0017] (4) When the planet carrier of the application is a rotating planet carrier, the fifth bearing provides a radial outward supporting force for the side of the rotating planet carrier close to the sun gear shaft, and the sixth bearing provides a radial inward supporting force for the side of the rotating planet carrier close to the power output mechanism, and the inner and outer supporting can improve the stability of the rotating planet carrier. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to make the purpose, technical scheme and beneficial effects of the application more clear, the application provides the following drawings for illustration: Figure 1 It is a structural schematic view of the first embodiment; Figure 2 It is a sectional schematic view of the first embodiment; Figure 3 It is a transmission principle schematic view of the first embodiment; Figure 4 It is a structural schematic view of the 3K planetary reduction mechanism of the first embodiment; Figure 5 It is a structural schematic view of the double planetary gear composed of the first planetary gear and the second planetary gear of the first embodiment or the second embodiment; Figure 6 This is a schematic diagram of the motor rotor structure of Embodiment 1 or Embodiment 2; Figure 7 This is a partially enlarged structural schematic diagram of the motor rotor of Embodiment 1 or Embodiment 2; Figure 8 This is a schematic diagram of the structure of Example 2; Figure 9 This is a cross-sectional schematic diagram of Example 2; Figure 10 This is a schematic diagram of the transmission principle in Example 2; Figure 11 This is a schematic diagram of the 3K planetary reduction mechanism in Example 2; Figure 12 This is a cross-sectional schematic diagram of Example 2 (the motor stator, double planetary gears, and hollow tubes are omitted).

[0019] The following labels are used in the attached diagram: 1-Motor half-shell, 2-Motor rotor, 201-First central hole, 202-Rotor lamination, 203-Magnet, 204-Card holder, 205-Bevel, 206-Limit angle, 207-Chamfer, 208-Weight reduction groove, 3-Motor stator, 4-Fixed gear ring, 5-Output gear ring, 6-Power output mechanism, 7-Third bearing, 8-Reducer half-shell, 9-Fixed ring, 10-Retaining ring, 11-Hollow tube, 1101-Second central hole, 12a-Floating planetary carrier, 12b-Rotating planetary carrier, 1 201-Fourth central hole, 1203-First extension, 1202-Second extension, 13-Sixth bearing, 14-Planetary shaft pin, 15-Planetary gear bearing, 16-Second planetary gear, 17-First planetary gear, 18-Sun gear shaft, 1801-Main shaft, 1802-Sun gear, 1803-Third central hole, 19a-Fourth bearing, 19b-Fifth bearing, 20-Second bearing, 21-First bearing, 22-Bearing mounting seat, 2201-Inner seat, 2203-Partition plate, 2202-Outer seat. Detailed Implementation

[0020] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0021] Example 1: like Figures 1-7 As shown, a hollow high-ratio 3K planetary reduction electric drive joint in this embodiment includes a housing, an inner rotor motor, a hollow tube 11, a 3K planetary reduction mechanism, and a power output mechanism 6 disposed within the housing. The internal rotor motor includes a motor stator 3 and a motor rotor 2 disposed inside the motor stator 3. The 3K planetary deceleration mechanism comprises a sun wheel shaft 18, a first planetary gear 17, a fixed gear ring 4, a second planetary gear 16, a planet carrier and an output gear ring 5; The sun wheel shaft 18 comprises a main shaft body 1801 and a sun wheel 1802 arranged on one side of the main shaft body 1801 in a coaxial synchronous rotation manner, the inside of the motor rotating shaft has a first middle hole 201, the first middle hole 201 is sleeved on the main shaft body 1801 in a coaxial synchronous rotation manner; the fixed gear ring 4 is fixed in position; the first planetary gear 17 is engaged between the sun wheel 1802 and the fixed gear ring 4; the first planetary gear 17 and the second planetary gear 16 are connected in a coaxial synchronous rotation manner and are both rotationally installed on the planet carrier; the second planetary gear 16 is engaged with the output gear ring 5, the output gear ring 5 is fixedly connected with the power output mechanism 6, and the power output mechanism 6 is rotationally connected with the shell; The hollow pipe 11 has a second middle hole 1101, one end of the hollow pipe 11 is rotationally connected with the shell, the middle part of the hollow pipe 11 passes through the sun wheel shaft 18 and the planet carrier, and the other end of the hollow pipe 11 is fixedly connected with the power output mechanism 6.

[0022] The first middle hole 201 of the motor rotating shaft is sleeved on the main shaft body 1801 in a coaxial synchronous rotation manner, that is, the first middle hole 201 of the motor rotating shaft is fixedly connected with the main shaft body 1801, and the connection mode can be interference fit to realize the connection of the two, or can be spline combined axial limiting structure to realize the connection of the two.

[0023] The electric drive joint adopts an inner rotor motor, which has faster torque response and better heat dissipation performance compared with an outer rotor motor, and meanwhile, the second middle hole 1101 of the hollow pipe 11 penetrates in the axial direction, the hollow pipe 11 passes through the sun wheel shaft 18 and the planet carrier, and a larger hollow size can be realized, which is conducive to the wiring arrangement of the electric drive joint.

[0024] 3K planetary reduction mechanism sun gear shaft 18 extends the main shaft body 1801 into the interior of the motor rotor 2, and the inner rotor motor and the power output mechanism 6 are respectively located on different sides of the 3K planetary reduction mechanism. The motor torque is reduced and increased in torque by the 3K planetary reduction mechanism composed of the sun gear shaft 18, the first planetary gear 17, the fixed gear ring 4, the second planetary gear 16, the planet carrier, and the output gear ring 5, and then the power is output by the power output mechanism 6. The 3K planetary reduction mechanism can achieve large speed ratio reduction. Moreover, the axial arrangement form of the 3K planetary reduction mechanism and the inner rotor motor reduces the radial size of the joint. Compared with the radial arrangement form, the same joint diameter premise, the technical scheme of the embodiment has a larger speed ratio, and the sun gear shaft 18 of the 3K planetary reduction mechanism extends into the motor rotor 2, which reduces the axial size of the joint, has high integration, and has small envelope size. Under the condition of the same envelope size, higher torque density can be achieved. When applied to a robot joint, a speed ratio of 99 can be achieved under the condition that the outer diameter of the joint is Φ125mm and the inner diameter of the hollow tube 11 is Φ10mm. The highest operating speed of the joint assembly can reach 400rpm, which is much higher than the current market products.

[0025] In the embodiment, the shell includes a motor half-shell 1 and a reducer half-shell 8, and the opposite sides of the motor half-shell 1 and the reducer half-shell 8 are open structures, and the opposite sides of the motor half-shell 1 and the reducer half-shell 8 are fixedly connected. The inner rotor motor is arranged in the motor half-shell 1, and the 3K planetary reduction mechanism is arranged in the reducer half-shell 8.

[0026] The connection mode of the motor half-shell 1 and the reducer half-shell 8 can be a threaded fastener connection mode. The motor half-shell 1 and the reducer half-shell 8 are both half-shell structures, which together form a complete shell, and can be beneficial to the lightweight of the shell.

[0027] In the embodiment, the motor half-shell 1 is connected with the hollow tube 11 through a first bearing 21, the motor half-shell 1 is connected with the main shaft body 1801 through a second bearing 20, and the reducer half-shell 8 is connected with the power output mechanism 6 through a third bearing 7. In the embodiment, the third bearing 7 is a cross roller bearing, and the cross roller bearing is axially positioned by a fixed ring 9 and a retainer 10. The first bearing 21, the second bearing 20, and the third bearing 7 can adopt a conventional deep groove ball bearing.

[0028] In the embodiment, the sun gear shaft 18 has a third through hole 1803 in the interior, the planet carrier has a fourth through hole 1201 in the interior, and the third through hole 1803 and the fourth through hole 1201 are arranged on the outside of the hollow tube 11 in a coaxial relative rotation mode.

[0029] The second middle hole 1101 and the third middle hole 1803 are coaxially and oppositely rotatable outside the hollow tube 11, that is, the inner diameter of the second middle hole 1101 and the third middle hole 1803 is greater than the outer diameter of the hollow tube 11, so that the sun gear shaft 18 and the planet carrier do not interfere with the outside of the hollow tube 11 when rotating.

[0030] In the embodiment, the planet carrier is a floating planet carrier 12a. The floating planet carrier 12a and the inner rotor motor are provided with a bearing mounting seat 22, the bearing mounting seat 22 includes an inner seat body 2201, a partition plate 2203 and an outer seat body 2202, the inner seat body 2201 is arranged on the side of the partition plate 2203 along the second middle hole 1101 in the radial direction, and the outer seat body 2202 is arranged on the side of the partition plate 2203 along the second middle hole 1101 in the radial direction. The inner seat body 2201 is connected with the main shaft body 1801 through a fourth bearing 19a, the outer seat body 2202 is fixedly connected with the housing, the fixed gear ring 4 is fixedly connected with the outer seat body 2202, one end of the floating planet carrier 12a close to the motor rotor 2 is sleeved on the inner seat body 2201, and the fourth middle hole 1201 is gap-fitted with the inner seat body 2201, and the other end of the floating planet carrier 12a close to the power output mechanism 6 is suspended. The fourth bearing 19a can be a conventional deep groove ball bearing.

[0031] The fixed gear ring 4 and the bearing mounting seat 22 of the 3K planetary reduction mechanism are fixedly connected with the reducer half housing 8, the output gear ring 5 of the 3K planetary reducer is fixedly connected with the power output mechanism 6, the output shaft is supported on the reducer half housing 8 through a cross roller bearing, the floating planet carrier 12a of the 3K planetary reduction mechanism is not supported by a bearing and is completely floating, and the completely floating design can ensure uniform distribution of loads between the planet gears.

[0032] The bearing mounting seat 22 divides the motor half housing 1 and the reducer half housing 8 into two sealed chambers, so that the gears of the inner rotor motor and the 3K planetary reduction mechanism are respectively located in independent sealed chambers, and the lubricating grease in the reducer half housing 8 does not flow into the motor half housing 1.

[0033] In the embodiment, the first planetary gear 17 and the second planetary gear 16 form a double planetary gear, which is rotatably installed on the planet shaft pin 14 through the planetary wheel bearing 15, and the planet wheel pin is fixedly connected with the planet carrier. The coaxial synchronous rotation connection between the first planetary gear 17 and the second planetary gear 16 means that the first planetary gear 17 and the second planetary gear 16 can be integrally formed to form a double planetary gear, which is rotatably installed on the planet shaft pin 14 through the planetary wheel bearing 15. The connection between the first planetary gear 17 and the second planetary gear 16 can also be a spline combined axial limiting structure to fix the two gears on the same gear shaft to realize the connection of the two gears, and the gear shaft is rotatably installed on the planet shaft pin 14 through the planetary wheel bearing 15.

[0034] In the embodiment, the motor rotor 2 is a frameless torque motor rotor 2, which includes a magnetic steel 203 and a rotor punching sheet 202. A plurality of clamping seats 204 are arranged on the side of the rotor punching sheet 202 radially outward of the first middle hole 201. The plurality of clamping seats 204 are arranged at intervals in the circumferential direction, and a clamping groove is formed between adjacent two clamping seats 204. The magnetic steel 203 is arranged in the clamping groove.

[0035] In the embodiment, the two sides of each clamping seat 204 are inclined surfaces 205, which are inclined in the direction of the inside of the clamping groove along the first middle hole 201 radially from the inside to the outside. The end of each clamping seat 204 away from the first middle hole 201 is provided with a limiting corner 206 extending to the inside of the clamping groove towards the two sides. The corner of the magnetic steel 203 is provided with a chamfer 207 matched with the shape of the limiting corner 206. The inside of each clamping seat 204 is provided with a weight-reducing groove 208.

[0036] The magnetic steel 203 is fixed in the clamping groove by the fixing glue, and the stability of the magnetic steel 203 is further enhanced by the inclined surface 205 and the limiting corner 206, so that the magnetic steel 203 will not fall off due to excessive centrifugal force in high-speed operation, realizing the high-speed operation of the internal rotor motor. The structural design of the inclined surface 205, the limiting corner 206 and the chamfer 207 can further increase the contact area of the magnetic steel 203 and the rotor punching sheet 202, and further increase the reliability of the high-speed operation of the motor.

[0037] Embodiment two: As Figures 5-12As shown, the hollow large speed ratio 3K planetary reduction type electric driving joint in the embodiment comprises a shell, further comprises an inner rotor motor, a hollow pipe 11, a 3K planetary reduction mechanism and a power output mechanism 6 arranged in the shell; wherein the shell, the inner rotor motor, the hollow pipe 11 and the power output mechanism 6 in the embodiment are basically the same as the structure in the first embodiment, the floating type planet carrier 12a in the 3K planetary reduction mechanism in the embodiment is replaced by a rotating type planet carrier 12b, both ends of the rotating type planet carrier 12b are installed through the fifth bearing 19b and the sixth bearing 13 respectively, and the bearing mounting seat 22 is cancelled, and the structure of the fixed ring gear 4 directly fixedly connected with the shell is adopted.

[0038] Specifically, In the embodiment, the inner rotor motor comprises a motor stator 3 and a motor rotor 2 arranged inside the motor stator 3; The 3K planetary reduction mechanism comprises a sun gear shaft 18, a first planetary gear 17, a fixed ring gear 4, a second planetary gear 16, a planet carrier and an output ring gear 5; The sun gear shaft 18 comprises a main shaft body 1801 and a sun gear 1802 arranged on one side of the main shaft body 1801 in a coaxial synchronous rotating manner, the inside of the motor shaft has a first middle hole 201, the first middle hole 201 is sleeved on the main shaft body 1801 in a coaxial synchronous rotating manner; the fixed ring gear 4 is fixed in position; the first planetary gear 17 is engaged between the sun gear 1802 and the fixed ring gear 4; the first planetary gear 17 and the second planetary gear 16 are connected in a coaxial synchronous rotating manner, and are both rotatably installed on the planet carrier; the second planetary gear 16 is engaged with the output ring gear 5, the output ring gear 5 is fixedly connected with the power output mechanism 6, and the power output mechanism 6 is rotatably connected with the shell; The hollow pipe 11 has a second middle hole 1101, one end of the hollow pipe 11 is rotatably connected with the shell, the middle part of the hollow pipe 11 passes through the sun gear shaft 18 and the planet carrier, and the other end of the hollow pipe 11 is fixedly connected with the power output mechanism 6.

[0039] In the embodiment, the shell comprises a motor half shell 1 and a reducer half shell 8, the opposite sides of the motor half shell 1 and the reducer half shell 8 are both open structures, and the opposite sides of the motor half shell 1 and the reducer half shell 8 are fixedly connected; the inner rotor motor is arranged in the motor half shell 1, and the 3K planetary reduction mechanism is arranged in the reducer half shell 8.

[0040] In the embodiment, the motor half shell 1 is connected with the hollow tube 11 through the first bearing 21, the motor half shell 1 is connected with the main shaft body 1801 through the second bearing 20, and the reducer half shell 8 is connected with the power output mechanism 6 through the third bearing 7.

[0041] In the embodiment, the sun gear shaft 18 has a third middle hole 1803 in the inside, the planet carrier has a fourth middle hole 1201 in the inside, and the second middle hole 1101 and the third middle hole 1803 are both externally sleeved on the hollow tube 11 in a coaxial relative rotation manner.

[0042] In the embodiment, the planet carrier is a rotating planet carrier 12b. The two ends of the rotating planet carrier 12b are respectively installed through the fifth bearing 19b and the sixth bearing 13. The one end of the rotating planet carrier 12b close to the motor rotor 2 is provided with a first extension 1203, and the one end of the rotating planet carrier 12b close to the power output mechanism 6 is provided with a second extension 1202; the inner ring of the fifth bearing 19b is externally sleeved on the main shaft body 1801, and the outer ring of the fifth bearing 19b is internally sleeved on the first extension 1203; the inner ring of the sixth bearing 13 is externally sleeved on the second extension 1202, and the outer ring of the sixth bearing 13 is internally sleeved on the power output mechanism 6; and the fixed gear ring 4 is fixedly connected with the housing. The fifth bearing 19b and the sixth bearing 13 can adopt a conventional deep groove ball bearing.

[0043] Compared with the floating planet carrier 12a in the first embodiment, the rotating planet carrier 12b is adopted in the embodiment, the fifth bearing 19b provides a radial outward supporting force for the side of the rotating planet carrier 12b close to the sun gear shaft 18, the sixth bearing 13 provides a radial inward supporting force for the side of the rotating planet carrier 12b close to the power output mechanism 6, and the inner and outer supporting can improve the stability of the rotating planet carrier 12b.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A hollow large speed ratio 3K planetary reduction electric drive joint comprising a housing, characterized in that: It also includes an inner rotor motor, a hollow tube (11), a 3K planetary reduction mechanism and a power output mechanism (6) arranged in the shell; The inner rotor motor includes a motor stator (3) and a motor rotor (2) arranged inside the motor stator (3); The 3K planetary reduction mechanism includes a sun gear shaft (18), a first planetary gear (17), a fixed gear ring (4), a second planetary gear (16), a planet carrier and an output gear ring (5); The sun gear shaft (18) includes a main shaft body (1801) and a sun gear (1802) arranged on one side of the main shaft body (1801) in a coaxial synchronous rotating manner, the inside of the motor rotating shaft has a first middle hole (201), the first middle hole (201) is sleeved on the main shaft body (1801) in a coaxial synchronous rotating manner; the fixed gear ring (4) is fixed in position; the first planetary gear (17) is engaged between the sun gear (1802) and the fixed gear ring (4); the first planetary gear (17) and the second planetary gear (16) are connected in a coaxial synchronous rotating manner and are both rotatingly installed on the planet carrier; the second planetary gear (16) is engaged with the output gear ring (5), the output gear ring (5) is fixedly connected with the power output mechanism (6), and the power output mechanism (6) is rotatingly connected with the shell; The hollow tube (11) has a second middle hole (1101), one end of the hollow tube (11) is rotatingly connected with the shell, the middle part of the hollow tube (11) passes through the sun gear shaft (18) and the planet carrier, and the other end of the hollow tube (11) is fixedly connected with the power output mechanism (6).

2. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 1, characterized in that: The shell includes a motor half shell (1) and a reducer half shell (8), the opposite sides of the motor half shell (1) and the reducer half shell (8) are both open structures, and the opposite sides of the motor half shell (1) and the reducer half shell (8) are fixedly connected; the inner rotor motor is arranged in the motor half shell (1), and the 3K planetary reduction mechanism is arranged in the reducer half shell (8).

3. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 2, characterized in that: The motor half shell (1) and the hollow tube (11) are connected through a first bearing (21), the motor half shell (1) and the main shaft body (1801) are connected through a second bearing (20), and the reducer half shell (8) and the power output mechanism (6) are connected through a third bearing (7).

4. The hollow large-ratio 3K planetary reduction electrically driven articulation according to any one of claims 1-3, characterized in that: The inside of the sun gear shaft (18) has a third middle hole (1803), the inside of the planet carrier has a fourth middle hole (1201), and the third middle hole (1803) and the fourth middle hole (1201) are arranged outside the hollow tube (11) in a coaxial opposite rotating manner.

5. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 4, characterized in that: The planet carrier is a floating planet carrier (12a); The floating planetary carrier (12a) and the inner rotor motor are provided with a bearing mounting seat (22), the bearing mounting seat (22) comprises an inner seat body (2201), a partition plate (2203) and an outer seat body (2202), the inner seat body (2201) is arranged on the side of the partition plate (2203) along the second middle hole (1101) radially inward, and the outer seat body (2202) is arranged on the side of the partition plate (2203) along the second middle hole (1101) radially outward; The inner seat body (2201) is connected with the main shaft body (1801) through the fourth bearing (19a), the outer seat body (2202) is fixedly connected with the shell, the fixed gear ring (4) is fixedly connected with the outer seat body (2202), one end of the floating planetary carrier (12a) close to the motor rotor (2) is sleeved on the inner seat body (2201), and the fourth middle hole (1201) is in clearance fit with the inner seat body (2201); and one end of the floating planetary carrier (12a) close to the power output mechanism (6) is suspended.

6. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 4, characterized in that: The planetary carrier is a rotary planetary carrier (12b); Both ends of the rotary planetary carrier (12b) are installed through the fifth bearing (19b) and the sixth bearing (13) respectively; One end of the rotary planetary carrier (12b) close to the motor rotor (2) is provided with a first extension part (1203), one end of the rotary planetary carrier (12b) close to the power output mechanism (6) is provided with a second extension part (1202), the inner ring of the fifth bearing (19b) is sleeved on the main shaft body (1801), the outer ring of the fifth bearing (19b) is sleeved in the first extension part (1203), the inner ring of the sixth bearing (13) is sleeved on the second extension part (1202), and the outer ring of the sixth bearing (13) is sleeved in the power output mechanism (6); The fixed gear ring (4) is fixedly connected with the shell.

7. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 4, characterized in that: The third bearing (7) is a cross roller bearing, and the cross roller bearing is axially positioned through a fixed ring (9) and a retainer (10).

8. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 1, characterized in that: The first planetary gear (17) and the second planetary gear (16) constitute a double planetary gear, the double planetary gear is rotatably installed on a planetary shaft pin (14) through a planetary wheel bearing (15), and the planetary wheel pin is fixedly connected with the planetary carrier.

9. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 1, characterized in that: The motor rotor (2) is a frameless torque motor rotor (2), the motor rotor (2) comprises a magnetic steel (203) and a rotor punching sheet (202), a plurality of clamping seats (204) are arranged on the side of the rotor punching sheet (202) along the first middle hole (201) radially outward, the plurality of clamping seats (204) are arranged at intervals in the circumferential direction, one clamping groove is formed between adjacent two clamping seats (204), and the magnetic steel (203) is arranged in the clamping groove.

10. The hollow large-ratio 3K planetary reduction electrically driven articulation according to claim 9, characterized in that: Both sides of each of the card seats (204) are inclined surfaces (205) inclined from inside to outside along the first middle hole (201) in a direction towards the inside of the card slot; the end of each of the card seats (204) away from the first middle hole (201) is provided with a limiting corner (206) extending to the inside of the card slot towards both sides, and a chamfer (207) on the corner of the magnetic steel (203) is provided with a shape matched with the limiting corner (206); the inside of each of the card seats (204) is provided with a weight-reducing groove (208).

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