Joint actuator and two-stage planetary reduction transmission mechanism thereof

Abstract

The invention discloses a two-stage planetary reduction transmission mechanism which comprises a first-stage planetary transmission mechanism and a second-stage planetary transmission mechanism. The first-stage planetary transmission mechanism comprises a first-stage sun gear and a first-stage gear ring; a plurality of first-stage planet gears and a first-stage planet carrier for mounting the first-stage planet gears are arranged between the first-stage sun gear and the first-stage gear ring; the first-stage planet gear is respectively meshed with the first-stage sun gear and the first-stage gear ring; the second-stage planetary transmission mechanism comprises a second-stage sun gear and a second-stage gear ring; a plurality of second-stage planet gears and a second-stage planet carrier for mounting the second-stage planet gears are arranged between the second-stage sun gear and the second-stage gear ring; the second-stage planet gear is respectively meshed with the second-stage sun gear and the second-stage gear ring; the fixing sleeve is arranged outside the first-stage gear ring and the second-stage gear ring in a sleeving mode, and the first-stage gear ring and the second-stage gear ring are in synchronous running fit with the fixing sleeve; the first-stage sun gear and the second-stage sun gear can rotate around the axis of the first-stage sun gear and the axis of the second-stage sun gear respectively. The invention further discloses a joint actuator.

Description

Technical Field

[0001] The present invention belongs to the technical field of robotics, and specifically relates to a joint actuator and its two-stage planetary reduction transmission mechanism. Background Art

[0002] As the core power component of a robot system, the robot joint actuator undertakes the key function of converting electrical energy into mechanical motion, and its performance directly affects the motion accuracy, load capacity, response speed and overall reliability of the robot. From a technical composition perspective, a typical joint actuator usually consists of modules such as a drive motor, a reduction mechanism, a sensor system, and a control unit. These components achieve functions such as torque amplification, motion conversion, and closed-loop control through precise integration. With the continuous expansion of robot application scenarios, from industrial manufacturing to medical services, from space exploration to home services, the performance requirements for joint actuators are becoming increasingly diversified and stringent.

[0003] Mechanically reduced joint actuators have long dominated the field of industrial robots. Their core technical feature is to reduce the output speed of the motor and amplify the torque through the principle of gear meshing. Such actuators usually adopt a three-stage architecture: the high-speed end provides the original power with a servo motor; the intermediate stage is a precision reducer to achieve speed and torque variation; the output end integrates a position / torque sensor to form a closed-loop control. According to the type of reduction mechanism, the mainstream solutions can be divided into three categories: harmonic reducers, planetary reducers, and RV reducers, each with distinct performance characteristics and application scenarios. Among them, the planetary reducer adopts a multi-stage gear parallel shunt structure, with advantages of high rigidity and large load-bearing capacity, and is commonly used in large-load industrial robots. However, if a large transmission ratio is to be achieved with existing planetary reducers, it will lead to an increase in the radial size, restricting their application in scenarios with limited space. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a joint actuator and its two-stage planetary reduction transmission mechanism, which can not only meet the requirement of a large transmission ratio, but also reduce the radial size.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention first proposes a two-stage planetary reduction transmission mechanism, including a first-stage planetary transmission mechanism and a second-stage planetary transmission mechanism;

[0007] The first-stage planetary transmission mechanism includes a first-stage sun gear and a first-stage ring gear. Between the first-stage sun gear and the first-stage ring gear, there are provided a number of first-stage planetary gears and a first-stage planetary carrier for mounting the first-stage planetary gears; the first-stage planetary gears are respectively meshed with the first-stage sun gear and the first-stage ring gear;

[0008] The secondary planetary transmission mechanism includes a secondary sun gear and a secondary ring gear. Between the secondary sun gear and the secondary ring gear, there are provided a number of secondary planet gears and a secondary planet carrier for mounting the secondary planet gears. The secondary planet gears are respectively meshed with the secondary sun gear and the secondary ring gear.

[0009] It further includes a fixed sleeve sleeved outside the first-stage ring gear and the secondary ring gear. The fixed sleeve is fixedly arranged, and the first-stage ring gear and the secondary ring gear are in synchronous rotation fit with the fixed sleeve. The first-stage sun gear and the secondary sun gear can both rotate around their axes, and there is a transmission connection between the first-stage planet carrier and the secondary sun gear.

[0010] Furthermore, internal splines are provided inside the fixed sleeve, external splines are respectively provided on the first-stage ring gear and the secondary ring gear, and the first-stage ring gear and the secondary ring gear are in spline fit with the fixed sleeve respectively.

[0011] Furthermore, a spacer sleeve is provided between the first-stage ring gear and the secondary ring gear, and the spacer sleeve is used to adjust the distance between the first-stage ring gear and the secondary ring gear.

[0012] Furthermore, the first-stage planet carrier is arranged between the first-stage planet gears and the secondary planet gears, and the first-stage planet carrier and the secondary sun gear rotate synchronously.

[0013] Furthermore, the rotating shafts of the first-stage planet carrier and the secondary sun gear are integrally formed.

[0014] The present invention also proposes a joint actuator, which includes a housing. Inside the housing, there is provided a motor assembly. The motor assembly includes a stator and a rotor sleeved outside the stator. A central through hole is provided inside the stator, and the two-stage planetary reduction transmission mechanism as described above is installed in the central through hole. The fixed sleeve is sleeved inside the central through hole and fixedly connected to the housing. The first-stage sun gear is in transmission connection with the rotor, and an output flange is provided on the secondary planet carrier.

[0015] Furthermore, the housing includes a housing body and an end cover covered on the housing body.

[0016] Furthermore, a connection disk is connected to the rotor. The connection disk is located between the housing body and the stator. An axially extending connection portion is provided at the center of the connection disk, and a connection through hole is provided inside the connection portion. The rotating shaft of the first-stage sun gear is installed in the connection through hole.

[0017] Furthermore, a relief hole for the connection portion is provided on the housing body. The inner diameter of the long ring gear is larger than the outer diameter of the connection portion. Deep groove ball bearings are respectively provided between the connection portion and the housing body and the long ring gear.

[0018] Furthermore, the fixed sleeve is fixedly connected to the end cover, a cross roller bearing is provided between the fixed sleeve, the end cover and the secondary planetary carrier, and a shaft sleeve is provided on the second planetary carrier and is located between the inner ring of the cross roller bearing and the secondary gear ring, and the shaft sleeve is used to locate the positions of the primary gear ring and the secondary gear ring in the axial direction.

[0019] The beneficial effects of the present invention are:

[0020] The joint actuator of the present invention, by setting a primary planetary transmission mechanism and a secondary planetary transmission mechanism, connects the rotor with the primary sun gear, connects the primary planet carrier with the secondary sun gear, and sets an output flange on the secondary planet carrier. In this way, the primary planetary gear is respectively engaged with the primary ring gear and the primary sun gear to achieve primary reduction, and the secondary planetary gear is respectively engaged with the secondary ring gear and the secondary sun gear to achieve secondary reduction. In this way, the total reduction transmission ratio of the two-stage planetary reduction transmission mechanism is the product of the transmission ratio of the primary planetary transmission mechanism and the transmission ratio of the secondary planetary transmission mechanism, that is, the two-stage reduction can meet the requirements of a larger transmission ratio, and can reduce the transmission ratios of the primary planetary transmission mechanism and the secondary planetary transmission mechanism respectively, thereby reducing the radial direction of the two-stage planetary reduction transmission mechanism. size; by setting a fixed sleeve, and arranging the primary gear ring and the secondary gear ring in the fixed sleeve and rotating synchronously with the fixed sleeve, and fixing the fixed sleeve in the central through hole of the stator, the axial length of the joint actuator can be reduced; in addition, by setting the primary gear ring and the secondary gear ring separately, the transmission ratio of the primary planetary transmission mechanism and the secondary planetary transmission mechanism can be flexibly adjusted, which can not only meet the requirements of a larger transmission ratio, but also by adjusting the transmission ratio of the primary planetary transmission mechanism and the secondary planetary transmission mechanism, the load capacity of the primary planetary transmission mechanism and the secondary planetary transmission mechanism can be flexibly adjusted to meet the load requirements; in summary, the joint actuator of the present invention can not only achieve the requirements of a larger transmission ratio, but also reduce the radial size without increasing the axial size. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0022] Figure 1 It is a structural schematic diagram of an embodiment of a joint actuator of the present invention;

[0023] Figure 2 for Figure 1 Left axonometric view of

[0024] Figure 3 for Figure 1 Right axonometric view.

[0025] Description of reference numerals:

[0026] 10 - Housing; 101 - Protrusion; 102 - Connecting hole; 11 - End cover; 12 - Stator; 13 - Rotor; 14 - Fixed sleeve; 15 - First - stage sun gear; 16 - First - stage ring gear; 17 - First - stage planet gear; 18 - First - stage planet carrier; 19 - Second - stage sun gear; 20 - Second - stage ring gear; 21 - Second - stage planet gear; 22 - Second - stage planet carrier; 23 - Output flange; 24 - Connecting plate; 241 - Connecting part; 242 - Connecting through - hole; 25 - Magnetic bead; 26 - Deep - groove ball bearing; 27 - Deep - groove ball bearing; 28 - Crossed roller bearing; 29 - Spacer sleeve; 30 - Bush; 31 - Circuit board. Detailed implementation manner

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the specific embodiments cited are not intended to limit the present invention.

[0028] As Figure 1 shown, the joint actuator of this embodiment includes a housing, and a motor assembly is provided inside the housing. In this embodiment, the housing includes a housing 10 and an end cover 11 mounted on the housing, and the end cover 11 and the housing 10 are fixedly connected. The motor assembly includes a stator 12 and a rotor 13 sleeved outside the stator 12. A central through - hole is provided in the stator, and a two - stage planetary reduction transmission mechanism is installed in the central through - hole.

[0029] In this embodiment, the two - stage planetary reduction transmission mechanism includes a first - stage planetary transmission mechanism, a second - stage planetary transmission mechanism, and a fixed sleeve 14. Specifically, the first - stage planetary transmission mechanism includes a first - stage sun gear 15 and a first - stage ring gear 16. Between the first - stage sun gear 15 and the first - stage ring gear 16, there are several first - stage planet gears 17 and a first - stage planet carrier 18 for installing the first - stage planet gears 17. The first - stage planet gears 17 are respectively meshed with the first - stage sun gear 15 and the first - stage ring gear 16. The second - stage planetary transmission mechanism includes a second - stage sun gear 19 and a second - stage ring gear 20. Between the second - stage sun gear 19 and the second - stage ring gear 20, there are several second - stage planet gears 21 and a second - stage planet carrier 22 for installing the second - stage planet gears 21. The second - stage planet gears 21 are respectively meshed with the second - stage sun gear 19 and the second - stage ring gear 20.

[0030] In this embodiment, the fixed sleeve 14 is sleeved outside the first-stage gear ring 16 and the second-stage gear ring 20, and the fixed sleeve 14 is fixedly arranged. The first-stage gear ring 16 and the second-stage gear ring 20 are in synchronous rotation fit with the fixed sleeve 14. That is, in this embodiment, the first-stage gear ring 16 and the second-stage gear ring 20 are fixed and do not rotate. Specifically, in this embodiment, internal splines are provided in the fixed sleeve 14, external splines are respectively provided on the first-stage gear ring 16 and the second-stage gear ring 20, and the first-stage gear ring 16 and the second-stage gear ring 20 are respectively in spline fit with the fixed sleeve 14. In this way, through the spline fit, the axial positions of the first-stage gear ring 16 and the second-stage gear ring 20 in the fixed sleeve 14 can be adjusted, and the first-stage gear ring 16 and the second-stage gear ring 20 can be prevented from rotating relative to the fixed sleeve 14.

[0031] In this embodiment, the first-stage sun gear 15 and the second-stage sun gear 19 can both rotate around their axes, and the first-stage planet carrier 18 is in transmission connection with the second-stage sun gear 19. Specifically, the first-stage planet carrier 18 is arranged between the first-stage planet gears 17 and the second-stage planet gears 21, and the first-stage planet carrier 18 and the second-stage sun gear 19 rotate synchronously. In a preferred embodiment of this embodiment, the rotating shafts of the first-stage planet carrier 18 and the second-stage sun gear 19 are integrally formed, which can simplify the structure.

[0032] In this embodiment, the fixed sleeve 14 is sleeved in the central through hole and fixedly connected to the housing. The first-stage sun gear 15 is in transmission connection with the rotor 13, and an output flange 23 is provided on the second-stage planet carrier 22. Specifically, a connection disk 24 is connected to the rotor 13, and the connection disk 24 is located between the housing 10 and the stator 12. An axially extending connection portion 241 is provided at the center of the connection disk 24, a connection through hole 242 is provided in the connection portion 241, and the rotating shaft of the first-stage sun gear 15 is installed in the connection through hole 242. In this embodiment, the first-stage sun gear 15 rotates synchronously with the rotor 13 through the connection disk 24. In this embodiment, a magnetic bead 25 is provided at one end of the connection through hole 242 facing away from the first-stage sun gear 15.

[0033] In this embodiment, a relief hole for the connection portion 241 is provided on the housing 10, and the inner diameter of the fixed sleeve 14 is larger than the outer diameter of the connection portion 241. Deep groove ball bearings 26 and 27 are respectively provided between the connection portion 241 and the housing 10 and the fixed sleeve 14.

[0034] In this embodiment, the fixed sleeve 14 is fixedly connected to the end cover 11, and a crossed roller bearing 28 is provided between the fixed sleeve 14 and the end cover 11 and the secondary planet carrier 22. In this embodiment, a spacer sleeve 29 is provided between the first ring gear 16 and the second ring gear 20. The spacer sleeve 29 is used to adjust the distance between the first ring gear 16 and the second ring gear 20. One end of the first ring gear 16 facing away from the second ring gear 20 is in limit fit with the outer ring of the deep groove ball bearing 27. In this embodiment, a bushing 30 is sleeved on the secondary planet carrier 22 between the inner ring of the crossed roller bearing 28 and the second ring gear 20. Under the axial positioning action of the spacer sleeve 29 and the bushing 30, the positions of the first ring gear 16 and the second ring gear 20 in the axial direction can be positioned.

[0035] Specifically, in this embodiment, the number of teeth of the first planet gears 17 is equal to that of the second planet gears 21, the number of teeth of the first sun gear 15 is equal to that of the second sun gear 19, and the number of teeth of the first ring gear 16 is equal to that of the second ring gear 20. That is, in this embodiment, the transmission ratios of the first planetary transmission mechanism and the second planetary transmission mechanism are the same. Of course, in some other embodiments, the transmission ratios of the first planetary transmission mechanism and the second planetary transmission mechanism may also be different. For example, the number of teeth of the first planet gears 17 and the second planet gears 21 can be set to be unequal, the number of teeth of the first sun gear 15 and the second sun gear 19 can be set to be unequal, or the number of teeth of the first ring gear 16 and the second ring gear 20 can be set to be unequal, which will not be elaborated here. Particularly, the transmission ratio of the first planetary transmission mechanism can be flexibly adjusted by adjusting the number of teeth of the first ring gear 16, the first planet gears 17, and the first sun gear 15. Similarly, the transmission ratio of the second planetary transmission mechanism can be flexibly adjusted by adjusting the number of teeth of the second ring gear 20, the second planet gears 21, and the second sun gear 19. By adjusting the transmission ratios of the first planetary transmission mechanism and the second planetary transmission mechanism, the load capacities of the first planetary transmission mechanism and the second planetary transmission mechanism can also be flexibly adjusted to meet the load requirements.

[0036] A convex portion 101 is provided on the end surface of the housing 10 of this embodiment, and connection holes 102 are provided at intervals on the convex portion 101. The convex portion 101 and the connection holes 102 are used for installing the circuit board 31, etc., which will not be elaborated here.

[0037] The joint actuator of this embodiment, by setting a primary planetary transmission mechanism and a secondary planetary transmission mechanism, connects the rotor to the primary sun gear, connects the primary planet carrier to the secondary sun gear, and sets an output flange on the secondary planet carrier. In this way, the primary planetary gear is respectively engaged with the primary ring gear and the primary sun gear to achieve primary reduction, and the secondary planetary gear is respectively engaged with the secondary ring gear and the secondary sun gear to achieve secondary reduction. In this way, the total reduction transmission ratio of the two-stage planetary reduction transmission mechanism is the product of the transmission ratio of the primary planetary transmission mechanism and the transmission ratio of the secondary planetary transmission mechanism, that is, the two-stage reduction can meet the requirements of a larger transmission ratio, and can reduce the transmission ratios of the primary planetary transmission mechanism and the secondary planetary transmission mechanism respectively, thereby reducing the radial direction of the two-stage planetary reduction transmission mechanism. size; by setting a fixed sleeve, and arranging the primary gear ring and the secondary gear ring in the fixed sleeve and rotating synchronously with the fixed sleeve, and fixing the fixed sleeve in the central through hole of the stator, the axial length of the joint actuator can be reduced; in addition, by setting the primary gear ring and the secondary gear ring separately, the transmission ratio of the primary planetary transmission mechanism and the secondary planetary transmission mechanism can be flexibly adjusted, which can not only meet the requirements of a larger transmission ratio, but also by adjusting the transmission ratio of the primary planetary transmission mechanism and the secondary planetary transmission mechanism, the load capacity of the primary planetary transmission mechanism and the secondary planetary transmission mechanism can be flexibly adjusted to meet the load requirements; in summary, the joint actuator of this embodiment can not only achieve the requirements of a larger transmission ratio, but also reduce the radial size without increasing the axial size.

[0038] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A two-stage planetary reduction drive mechanism, characterized in that: It includes a first-stage planetary transmission mechanism and a second-stage planetary transmission mechanism; The first-stage planetary transmission mechanism includes a first-stage sun gear and a first-stage ring gear. Between the first-stage sun gear and the first-stage ring gear, there are provided a number of first-stage planetary gears and a first-stage planetary carrier for mounting the first-stage planetary gears; the first-stage planetary gears are respectively meshed with the first-stage sun gear and the first-stage ring gear; The second-stage planetary transmission mechanism includes a second-stage sun gear and a second-stage ring gear. Between the second-stage sun gear and the second-stage ring gear, there are provided a number of second-stage planetary gears and a second-stage planetary carrier for mounting the second-stage planetary gears; the second-stage planetary gears are respectively meshed with the second-stage sun gear and the second-stage ring gear; It further includes a fixed sleeve sleeved outside the first-stage ring gear and the second-stage ring gear. The fixed sleeve is fixedly arranged, and the first-stage ring gear and the second-stage ring gear are in synchronous rotation fit with the fixed sleeve; the first-stage sun gear and the second-stage sun gear can both rotate around their axes, and the first-stage planetary carrier is in transmission connection with the second-stage sun gear.

2. The two-stage planetary reduction transmission mechanism according to claim 1, wherein: Internal splines are provided in the fixed sleeve, and external splines are respectively provided on the first-stage ring gear and the second-stage ring gear. The first-stage ring gear and the second-stage ring gear are respectively in spline fit with the fixed sleeve.

3. The two-stage planetary reduction drive mechanism according to claim 2, wherein: A spacer sleeve is provided between the first-stage ring gear and the second-stage ring gear, and the spacer sleeve is used to adjust the distance between the first-stage ring gear and the second-stage ring gear.

4. The two-stage planetary reduction drive mechanism according to claim 1, characterized in that: The first-stage planetary carrier is arranged between the first-stage planetary gears and the second-stage planetary gears, and the first-stage planetary carrier rotates synchronously with the second-stage sun gear.

5. The two-stage planetary reduction drive mechanism according to claim 4, characterized in that: The rotating shafts of the first-stage planetary carrier and the second-stage sun gear are integrally formed.

6. An articular actuator, characterized in that: It includes a housing. Inside the housing, there is provided a motor assembly. The motor assembly includes a stator and a rotor sleeved outside the stator. A central through hole is provided in the stator, and a two-stage planetary reduction transmission mechanism as described in any one of claims 1-5 is installed in the central through hole; the fixed sleeve is sleeved in the central through hole and fixedly connected to the housing. The first-stage sun gear is in transmission connection with the rotor, and an output flange is provided on the second-stage planetary carrier.

7. The joint actuator according to claim 6, characterized in that: The housing includes a housing body and an end cover covered on the housing body.

8. The joint actuator according to claim 7, wherein: A connection disk is connected to the rotor. The connection disk is located between the housing body and the stator; an axially extending connection portion is provided at the center of the connection disk, and a connection through hole is provided in the connection portion. The rotating shaft of the first-stage sun gear is installed in the connection through hole.

9. The joint actuator according to claim 8, wherein: A relief hole for the connection portion is provided on the housing body. The inner diameter of the long ring gear is larger than the outer diameter of the connection portion; deep groove ball bearings are respectively provided between the connection portion and the housing body and the long ring gear.

10. The joint actuator according to claim 7, characterized in that: The fixed sleeve is fixedly connected to the end cover. Crossed roller bearings are provided between the fixed sleeve and the end cover and the second-stage planetary carrier. A sleeve is sleeved on the second planetary carrier and located between the inner ring of the crossed roller bearing and the second-stage ring gear. The sleeve is used to position the first-stage ring gear and the second-stage ring gear in the axial direction.

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