Compact joint
Through compact joint design, combined with the advantages of harmonic reducers and cycloid pinwheel reducers, the problems of difficult processing and poor rigidity of existing robot joints are solved, and a compact structure, reduced parts and improved detection accuracy are achieved, meeting the needs of miniaturization and lightweighting.
Patent Information
- Application Number
- CN202422980142.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2034-12-04
AI Technical Summary
Existing robot joints are difficult to process, have many parts and poor rigidity, making it difficult to meet the needs of miniaturization and lightweighting.
It adopts a compact joint design, combining the advantages of harmonic reducer and cycloid pinwheel reducer, adopts the tooth profile of harmonic reducer to reduce the processing difficulty and the number of parts, and increases the torque through the design of meshing gears and inner ring gears, uses rigid parts such as outer ring and meshing gears, and integrates direct force sensors to improve detection accuracy.
It achieves a compact structure, reduces processing difficulty and the number of parts, enhances joint rigidity, improves detection accuracy and responsiveness, and meets the requirements of miniaturization and lightweighting.
Smart Images
Figure CN223419593U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of robot joints, and particularly relates to a compact joint. Background Art
[0002] Small robots, especially collaborative robots, are required to be miniaturized, lightweight, and modular. Robotic joint assemblies are the foundation of modular robots. Integrated joints offer numerous advantages, simplifying design, facilitating rapid assembly, and enabling customization of robots to meet specific functional requirements. Robotic joints are key components, and their design directly impacts their overall performance. Joint size is a key factor influencing the overall size of a robot.
[0003] Existing integrated joints use harmonic reducers or cycloid reducers. Cycloid reducers are difficult to manufacture and require many parts. Harmonic reducers use flexible wheels to transmit power, resulting in poor rigidity. Utility Model Content
[0004] In order to solve the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a compact joint, reduce the processing difficulty and the number of parts, and ensure the rigidity of the joint.
[0005] The technical solution adopted by this utility model is:
[0006] A compact joint includes a shell, a motor stator is fixedly connected to the shell, a motor rotor is built in the motor stator, a magnetic steel is fixedly connected to the motor rotor, an eccentric shaft is fixedly connected to the motor rotor, a meshing gear and an inner ring are rotatably connected to the eccentric shaft, the inner ring is circumferentially fixed relative to the meshing gear, an outer ring is fixedly connected to one end of the shell, an inner gear ring is arranged inside the outer ring, the meshing gear meshes with the inner gear ring, and the number of teeth of the meshing gear is less than the number of teeth of the inner gear ring.
[0007] The motor's rotor rotates, driving the eccentric, which in turn, through rollers, drives the meshing gears to roll in mesh with the inner ring gear. Because the meshing gears have fewer teeth than the inner ring gear, after one rotation of the eccentric, the meshing gears rotate less relative to the inner ring gear by the angle corresponding to the fewer teeth, thus reducing speed and increasing torque.
[0008] The motor stator, motor rotor, eccentric shaft, meshing gear, inner ring, outer ring, etc. of the utility model are all arranged in the housing, and each structure is closely arranged. The utility model adopts an integrated design and has a compact structure.
[0009] This utility model combines the advantages of harmonic reducers and cycloid pinwheel reducers, adopts the tooth profile of harmonic reducer, reduces the processing difficulty and the number of parts compared with cycloid pinwheel reducer; the outer ring and meshing gears are both rigid parts, the elastic deformation of the parts is small, and has stronger rigidity than the harmonic reducer.
[0010] As a preferred solution of the present invention, an inner ring connecting ring is rotatably connected to the eccentric shaft, and the inner ring connecting ring is located on the side of the meshing gear away from the inner ring. The inner ring and the inner ring connecting ring are meshed with each other and locked with screws. A cross sliding fork is provided between the inner ring and the meshing gear, and between the meshing gear and the inner ring connecting ring.
[0011] There are two or more meshing gears, evenly distributed circumferentially within the outer ring. The meshing gears engage the eccentric shaft via rollers. The meshing gears are slidably connected to the inner ring and the inner ring connecting ring via a cross-shaped sliding fork. The inner ring and the inner ring connecting ring are profiled and locked with screws, thereby fixing the inner ring and the inner ring connecting ring to each other. The inner ring, the first cross-shaped sliding fork, the first meshing gear, the second meshing gear, the second cross-shaped sliding fork, and the inner ring connecting ring are connected into a whole. The rotational torque of the meshing gears is transmitted to the cross-shaped sliding fork, which in turn transmits the torque to the inner ring and the inner ring connecting ring.
[0012] As a preferred solution of the present invention, the inner ring is fixedly connected to a detection center tube, which is sleeved in the eccentric shaft, and a detection center ring is fixed to the end of the detection center tube away from the inner ring, on which the output magnetic steel is installed; the end of the outer shell away from the outer ring is fixedly connected to a back cover, on which a detection plate is installed, and on which an output detection element for detecting the output magnetic steel is installed.
[0013] As a preferred solution of the present invention, an input detection magnet is installed on the motor rotor, and an input detection element for detecting the input detection magnet is installed on the detection board.
[0014] As a preferred solution of the present invention, a magnetic shield is fixed on the detection board, and the magnetic shield separates the input detection element and the output detection element, thereby reducing mutual interference and improving detection accuracy.
[0015] As a preferred solution of the present invention, a driving board is installed on the rear cover, and the detection board and the motor stator are electrically connected to the driving board.
[0016] As a preferred solution of the present invention, the housing is fixedly connected to the motor stator via a first pin, and the motor rotor is fixedly connected to the eccentric shaft via a second pin. The first pin serves to fix the motor stator, and the second pin serves to transmit the torsional load.
[0017] As a preferred embodiment of the present invention, the outer ring comprises an inner outer ring, a deformable ring, and an outer outer ring, which are fixedly connected in sequence from the inside out. The inner outer ring is connected to an iron core support, which is mounted on an iron core. The outer outer ring is connected to an induction coil symmetrical to the iron core. This integrated direct force sensor offers greater responsiveness than strain gauge force measurement methods, with a smaller detection component. The outer ring is hollowed out, eliminating the need for additional space in the joint.
[0018] As a preferred solution of the present invention, the outer ring, inner ring and the deformable ring are an integral part, and the two ends of the deformable ring are provided with an upper retaining ring and a lower retaining ring welded to the outer ring and inner ring.
[0019] As a preferred solution of the present invention, rollers are provided between the inner ring and the outer ring, and the outer ring, the inner ring and the rollers form a cross roller bearing.
[0020] The beneficial effects of the utility model are:
[0021] 1. This utility model combines the advantages of harmonic reducer and cycloid pinwheel reducer, adopts the tooth profile of harmonic reducer, reduces the processing difficulty and the number of parts compared with cycloid pinwheel reducer; the outer ring and meshing gear are both rigid parts, the elastic deformation of the parts is small, and it has stronger rigidity than the harmonic reducer.
[0022] 2. The motor stator, motor rotor, eccentric shaft, meshing gear, inner ring, outer ring, etc. of the utility model are all arranged in the housing, and each structure is closely arranged. The utility model adopts an integrated design and has a compact structure.
[0023] 3. The utility model integrates a direct force sensor, which has a higher responsiveness than the strain gauge force detection method, and the detection component is smaller in size. The outer ring is hollowed out and does not occupy additional space in the joint. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a cross-sectional view of the utility model in Example 1;
[0025] Figure 2 It is a left side view of the utility model in Example 1;
[0026] Figure 3 It is a cross-sectional view of the utility model in Example 2;
[0027] Figure 4 It is a left side view of the utility model in Example 2;
[0028] Figure 5 It is a structural diagram of the outer ring in Example 2.
[0029] In the figure: 1-outer ring; 2-inner ring; 3-inner ring connecting ring; 4-meshing gear; 5-cross sliding fork; 6-roller; 7-eccentric shaft; 8-large bearing; 9-housing; 10-first pin; 11-motor stator; 12-coil; 13-magnet; 14-motor rotor; 15-input detection magnet; 16-input detection element; 17-magnetic shield; 18-detection plate; 19-detection center tube; 20-detection center ring; 21-small bearing; 22-output magnet; 23-output detection element; 24-back cover; 25-drive plate; 26-sealing cover; 27-second pin; 28-roller; 29-lower retaining ring; 30-upper retaining ring; 31-iron core; 32-induction coil; 1.1-outer ring inner ring; 1.2-deformation ring; 1.3-outer ring outer ring; 1.1.1-iron core support. DETAILED DESCRIPTION
[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.
[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without inventive effort are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features therein may be combined with each other unless there is a conflict.
[0032] Example 1:
[0033] like Figure 1 and Figure 2 As shown, the compact joint of this embodiment includes an inner rotor motor assembly and a reducer component. The inner rotor motor assembly, serving as the joint's power source, consists of a motor stator 11, coils 12, magnets 13, a motor rotor 14, and input detection magnets 15. The motor stator 11 is secured to the inner wall of the housing 9 via a first pin 10. The motor rotor 14 is connected to the eccentric shaft 7 via a second pin 27, which transmits torsional loads.
[0034] The reducer assembly includes an outer ring 1, which is connected to the housing 9 via screws and locating pins. Inside the outer ring 1 is an inner gear ring, which is meshed with two or more meshing gears 4. The meshing gears 4 are evenly distributed around the circumference of the outer ring 1. The meshing gears 4 engage with an eccentric shaft 7 via rollers 6. The meshing gears 4 are slidably connected to the inner ring 2 and the inner ring connecting ring 3 via a crosshair 5. The inner ring 2 and the inner ring connecting ring 3 are profiled and locked with screws, thereby securing the inner ring 2 and the inner ring connecting ring 3. This unit connects the inner ring 2, the first crosshair 5, the first meshing gear 4, the second meshing gear 4, the second crosshair 5, and the inner ring connecting ring 3 into a single unit. The rotational torque of the meshing gear 4 is transmitted to the crosshair 5, which in turn transmits the torque to the inner ring 2 and the inner ring connecting ring 3.
[0035] After the motor rotor 14 rotates, it drives the eccentric wheel to rotate. The rotation of the eccentric wheel drives the meshing gear 4 to mesh and roll with the inner teeth of the outer ring 1 through the roller 6. Since the meshing gear 4 has fewer teeth than the inner ring gear, after the eccentric wheel rotates one circle, the angle of rotation of the meshing gear 4 relative to the inner ring gear is less than one circle by the angle relative to the fewer teeth, thereby achieving the purpose of reducing the speed and increasing the torque.
[0036] Outer ring 1 is designed with grooves for rollers 28, and inner ring 2 also has grooves for rollers 28. After rollers 28 are inserted into the grooves, outer ring 1 and inner ring 2 form a crossed roller bearing. These two rings also serve as structural components of the reducer. The integrated design of the structural components and transmission components makes the structure more compact, reducing the number of parts, simplifying processing, and lowering assembly complexity and cost.
[0037] The detection center tube 19 is connected to the inner ring 2 by screws. The detection center ring 20 is fixed to the detection center tube 19. The detection center ring 20 is connected to the rear cover 24 by a small bearing 21. The output magnet 22 is arranged on the detection center ring 20. At the same time, the input detection magnet 15 is also arranged inside the motor rotor 14. The rear cover 24 is installed at the rear end of the motor. The rear cover 24 is connected to the outer shell 9 by screws and limits the axial freedom of the motor. A detection plate 18 is installed on the rear cover 24 relative to the inner surface of the joint. Two sets of Hall detection elements are arranged on the detection plate 18. The input detection element 16 detects the input detection magnet 15, and the output detection element 23 detects the output magnet 22, so that the joint achieves the purpose of closed-loop control. The two sets of detection elements and the detected magnet 13 are separated by a shielding cover to reduce mutual interference and improve detection accuracy.
[0038] A drive board 25 is arranged outside the rear cover 24. The detection board 18 is electrically connected to the drive board 25, and the motor is also electrically connected to the drive board 25. A cover 26 is installed at the rear end of the drive board 25. The cover 26 is fixed to the rear cover 24 with screws to ensure the protection and dustproof requirements of the drive board 25.
[0039] The utility model combines the advantages of a harmonic reducer and a cycloid pinwheel reducer, adopts the tooth profile of a harmonic reducer, reduces the processing difficulty and the number of parts compared to a cycloid pinwheel reducer; the outer ring 1 and the meshing gear 4 are both rigid parts, the elastic deformation of the parts is small, and they have stronger rigidity than a harmonic reducer.
[0040] The motor stator 11, the motor rotor 14, the eccentric shaft 7, the meshing gear 4, the inner ring 2, the outer ring 1, etc. of the present invention are all arranged in the housing 9, and each structure is closely arranged. The present invention adopts an integrated design and has a compact structure.
[0041] Example 2:
[0042] like Figures 3 to 5 As shown, the compact joint with its own torque detection device in this embodiment includes a sensor assembly, a reducer component and an inner rotor motor assembly.
[0043] The inner rotor motor assembly, serving as the joint's power source, comprises a motor stator 11, coils 12, magnets 13, a motor rotor 14, and an input detection magnet 15. The electronic stator is secured to the inner wall of the housing 9 via a first pin 10, while the motor rotor 14 is connected to the eccentric shaft 7 via a second pin 27. The first pin 10 secures the motor, while the second pin 27 transmits the torsional load.
[0044] The reducer assembly includes an outer ring 1, which is connected to the housing 9 via screws and locating pins. Inside the outer ring 1 is an inner gear ring, housing two or more meshing gears 4 that mesh with the inner gears. The meshing gears 4 are evenly distributed around the circumference of the outer ring 1. The meshing gears 4 engage with an eccentric shaft 7 via rollers 6. The meshing gears 4 are slidably connected to the inner ring 2 and the inner ring connecting ring 3 via a crosshair 5. The inner ring 2 and the inner ring connecting ring 3 are profiled and locked with screws, securing the inner ring 2 and the inner ring connecting ring 3. This secures the inner ring 2, the first crosshair 5, the first meshing gear 4, the second meshing gear 4, the second crosshair 5, and the inner ring connecting ring 3 into a single unit. The rotational torque of the meshing gear 4 is transmitted to the crosshair 5, which in turn transmits the torque to the inner ring 2 and the inner ring connecting ring 3.
[0045] After the motor rotor 14 rotates, it drives the eccentric wheel to rotate. The rotation of the eccentric wheel drives the meshing gear 4 to mesh and roll with the inner teeth of the outer ring 1 through the roller 6. Since the meshing gear 4 has fewer teeth than the inner teeth of the outer ring 1, after the eccentric wheel rotates one circle, the angle of rotation of the meshing gear 4 relative to the inner gear ring is less than one circle by the angle relative to the fewer teeth, thereby achieving the purpose of reducing the speed and increasing the torque.
[0046] The outer ring 1 comprises an inner ring 1.1, a deforming ring 1.2, an outer ring 1.3, and a core support 1.1.1. Together with the core 31 and the induction coil 32, they form a force sensor. The core 31 is fixed to the core support 1.1.1, and the induction coil 32 is fixed near the outer ring 1.3. The core support 1.1.1 is connected to the inner ring 1.1. When the inner ring 1.1 is subjected to a torsional torque, the deforming ring 1.2 deforms, causing the inner ring 1.1 and the outer ring 1.3 to move relative to each other circumferentially. This also causes the core 31 on the core support 1.1.1 to move closer to or further away from the induction coil 32. This causes the electrical signal within the coil 12 to change, and after calibration, the force applied can be calculated.
[0047] An upper retaining ring 30 and a lower retaining ring 29 are welded to each end of the outer and inner rings 1.1, respectively. The lower retaining ring 29 is designed with a groove for rollers 28, and the inner ring 2 also has a groove for rollers 28. With rollers 28 inserted into the grooves, the outer and inner rings 1 and 2 form a crossed roller bearing. The outer and inner rings 1 and 2 serve as structural components of the reducer itself, integrating the structural components and transmission components for a more compact design, reducing the number of parts, eases machining difficulty, and reduces assembly complexity and cost. The outer ring 1 is designed with two materials and secured together through an interference fit and the welding of the upper and lower retaining rings 30 and 29. This reduces the mass of the outer ring 1 and the entire joint while maintaining high rigidity.
[0048] The detection center tube 19 is connected to the end face of the inner ring 2 via screws. The detection center ring 20 is fixed to the detection center tube 19. The detection center ring 20 is connected to the rear cover 24 by a small bearing 21. The detection center ring 20 is equipped with an output magnet 22. At the same time, the input detection magnet 15 is also arranged inside the motor rotor 14. The rear cover 24 is installed at the rear end of the motor. The rear cover 24 is connected to the outer shell 9 via screws and also limits the axial freedom of the motor. The detection plate 18 is mounted on the rear cover 24 relative to the inner surface of the joint. The detection plate 18 is equipped with two sets of Hall effect detection elements, one inside and one outside. The input detection element 16 detects the input detection magnet 15, and the output detection element 23 detects the output magnet 22, thereby achieving closed-loop control of the joint. The two sets of detection elements and the detected magnet 13 are separated by a shielding cover, reducing mutual interference and improving detection accuracy.
[0049] The utility model combines the advantages of a harmonic reducer and a cycloid pinwheel reducer, adopts the tooth profile of a harmonic reducer, reduces the processing difficulty and the number of parts compared to a cycloid pinwheel reducer; the outer ring 1 and the meshing gear 4 are both rigid parts, the elastic deformation of the parts is small, and they have stronger rigidity than a harmonic reducer.
[0050] The motor stator 11, the motor rotor 14, the eccentric shaft 7, the meshing gear 4, the inner ring 2, the outer ring 1, etc. of the present invention are all arranged in the housing 9, and each structure is closely arranged. The present invention adopts an integrated design and has a compact structure.
[0051] The utility model integrates a direct force sensor, which has a higher responsiveness than the strain gauge force detection method, and the detection component is smaller in size. The outer ring 1 is hollowed out and does not occupy additional space in the joint.
[0052] The present invention is not limited to the above-mentioned optional implementation methods. Anyone can derive various other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any technical solution that falls within the scope defined by the claims of the present invention shall fall within the scope of protection of the present invention.
Claims
1. A compact joint, characterized in that: The invention comprises a housing (9), wherein a motor stator (11) is fixedly connected to the housing (9), a motor rotor (14) is built in the motor stator (11), a magnetic steel (13) is fixedly connected to the motor rotor (14), the motor rotor (14) is fixedly connected to an eccentric shaft (7), a meshing gear (4) and an inner ring (2) are rotatably connected to the eccentric shaft (7), the inner ring (2) is circumferentially fixed relative to the meshing gear (4), one end of the housing (9) is fixedly connected to an outer ring (1), an inner gear ring is arranged in the outer ring (1), the meshing gear (4) meshes with the inner gear ring, and the number of teeth of the meshing gear (4) is less than the number of teeth of the inner gear ring.
2. A compact joint according to claim 1, characterized in that: An inner ring connecting ring (3) is rotatably connected to the eccentric shaft (7). The inner ring connecting ring (3) is located on a side of the meshing gear (4) away from the inner ring (2). The inner ring (2) and the inner ring connecting ring (3) are fixed by contour meshing and screw locking. A cross sliding fork (5) is provided between the inner ring (2) and the meshing gear (4) and between the meshing gear (4) and the inner ring connecting ring (3).
3. A compact joint according to claim 1, characterized in that: The inner ring (2) is fixedly connected to a detection center tube (19), which is sleeved in the eccentric shaft (7). A detection center ring (20) is fixed to the end of the detection center tube (19) away from the inner ring (2), and an output magnetic steel (22) is installed on the detection center ring (20); the outer shell (9) is fixedly connected to a rear cover (24) at one end away from the outer ring (1), and a detection plate (18) is installed on the rear cover (24), and an output detection element (23) for detecting the output magnetic steel (22) is installed on the detection plate (18).
4. A compact joint according to claim 3, characterized in that: An input detection magnet (15) is mounted on the motor rotor (14), and an input detection element (16) for detecting the input detection magnet (15) is mounted on the detection plate (18).
5. A compact joint according to claim 4, characterized in that: A magnetic shielding cover (17) is fixed on the detection plate (18), and the magnetic shielding cover (17) separates the input detection element (16) and the output detection element (23).
6. A compact joint according to claim 4, characterized in that: A driving plate (25) is mounted on the rear cover (24), and the detection plate (18) and the motor stator (11) are both electrically connected to the driving plate (25).
7. The compact joint according to claim 1, characterized in that: The housing (9) is fixedly connected to the motor stator (11) via a first pin (10), and the motor rotor (14) is fixedly connected to the eccentric shaft (7) via a second pin (27).
8. The compact joint according to claim 1, characterized in that: The outer ring (1) comprises an outer ring inner ring, a deformation ring (1.2) and an outer ring outer ring (1.3) which are fixedly connected in sequence from the inside to the outside; the outer ring inner ring (1.1) is connected to an iron core support, an iron core (31) is mounted on the iron core support, and the outer ring outer ring (1.3) is connected to an induction coil (32) symmetrical to the iron core (31).
9. A compact joint according to claim 8, characterized in that: The outer ring and inner ring (1.1) and the deformation ring (1.2) are an integral part; an upper retaining ring (30) is welded to one end of the deformation ring (1.2), and a lower retaining ring (29) is welded to the other end of the deformation ring (1.2).
10. A compact joint according to any one of claims 1 to 9, characterized in that: A roller (28) is provided between the inner ring (2) and the outer ring (1); the outer ring (1), the inner ring (2) and the roller (28) form a cross roller bearing.