High-performance cycloid joint

Abstract

The invention discloses a high-performance cycloid joint, and relates to the technical field of robot joints. The frameless torque motor is installed in the tail end of the gear pin shell, the cycloid speed reducer is installed in the head end of the gear pin shell, the contact part of two cycloid gears is completely replaced by a needle bearing structure, the eccentric shaft is sleeved on the front half section of the center cylinder, the rear half section of the center cylinder extends into the rotor and is rotatably connected with the rotor, and the output disc is rotatably installed in an inner hole of the head end cover. The head end of the center cylinder extends out of the output disc and is fixedly connected with the output disc, and the PCB is fixed outside the tail end cover and connected with the two encoder magnetic rings to measure the rotating speed of the output disc and the rotor in real time. A frameless torque motor and a cycloid speed reducer are integrated and optimized, sliding friction is converted into rolling friction through a needle bearing structure, the transmission efficiency is improved, internal wiring of the joint is achieved through a center cylinder, the control precision is improved through an input encoder and an output encoder, and meanwhile good transparency is achieved; and when impacted, force can be transmitted to the motor part to reduce the risk of damage to the speed reducer.

Description

Technical Field

[0001] The invention relates to the technical field of robot joints, in particular to a high-performance cycloid joint. Background Art

[0002] As the actuator of the robot, the joint converts the received electrical signal into angular displacement or angular velocity on the motor shaft and outputs it after passing through the reducer. Each joint movement of the robot depends on the joint drive to achieve multi-degree-of-freedom movement. At present, joint motors mostly use planetary reducers, which have compact structure, large reduction ratio and high transmission efficiency.

[0003] However, humanoid robots require a smaller and more stable reducer to achieve flexible movement of robot joints under heavy loads. Compared with traditional planetary reducers, cycloid reducers have the advantages of high precision, high efficiency, stable operation and long service life, and are compact and small in size. Due to the use of the planetary transmission principle, the input and output shafts are on the same axis, making the model as small as possible, making it more suitable as a joint for humanoid robots.

[0004] However, at present, the integration and control accuracy of the joints to the cycloid reducer are not high, which can easily cause damage to the cycloid reducer when subjected to external impact. In addition, the traditional cycloid reducer directly transmits the output shaft through the cycloid gear, which produces strong sliding friction, and the transmission efficiency needs to be further improved. In addition, humanoid robots generally have a high degree of freedom, and the corresponding number of joints is large, which also poses a problem for the routing of joints at this stage. Summary of the invention

[0005] In order to address the shortcomings of the background technology, the present invention provides a high-performance cycloid joint, which integrates and optimizes a frameless torque motor and a cycloid reducer, converts sliding friction into rolling friction through a needle bearing structure to improve transmission efficiency, realizes internal wiring of the joint through a center tube, and has input and output encoders to improve control accuracy. At the same time, it has good transparency and can transmit force to the motor part when impacted to reduce the risk of reducer damage.

[0006] To achieve the above object, the present invention adopts the following technical scheme: a high-performance cycloid joint, comprising a housing portion, an output transmission portion, a cycloid reducer, a frameless torque motor and a PCB board;

[0007] The housing portion includes a pin housing, a head end cover and a tail end cover, the pin housing is a cylindrical structure, the head end cover and the tail end cover are annular structures and are respectively fixed at the head and tail ends of the pin housing;

[0008] The frameless torque motor comprises a stator and a rotor, wherein the stator is coaxially limited and inserted inside the end of the pin housing, and the rotor is coaxially clearance-fitted and arranged inside the stator;

[0009] The cycloid reducer is installed inside the front end of the gear pin housing, and includes an eccentric shaft, two cycloid gears, multiple output pins and multiple cylindrical pins. The eccentric shaft is directly connected to the rotor for transmission. A circle of needle rollers is respectively arranged between the two cycloid gears and the eccentric shaft. The multiple output pins are uniformly inserted between the output disk and the pin fixing disk along the circumferential direction. The middle section of the output pin is covered with a first needle roller bearing and passes through the bearing through holes correspondingly arranged on the two cycloid gears. The multiple cylindrical pins are uniformly inserted between the front end cover and the middle prefabricated convex ring on the inner wall of the gear pin housing along the circumferential direction. The middle section of the cylindrical pin is covered with a second needle roller bearing and contacts and cooperates with the tooth profiles of the two cycloid gears.

[0010] The output transmission part includes an output disk, a center cylinder and a pin fixing disk. The center cylinder is coaxially arranged inside the gear pin housing. The eccentric shaft is hollow and sleeved on the front half of the center cylinder. The rear half of the center cylinder extends into the center hole of the rotor and is rotatably connected thereto. The output disk is rotatably installed in the inner hole of the head end cover. The head end of the center cylinder extends out through a through hole preset in the center of the output disk and is connected and fixed thereto. The through hole preset in the center of the pin fixing disk is connected and supported by the end of the outer wall of the eccentric shaft through a bearing.

[0011] The inner side of the PCB board is connected to an input encoder magnetic ring and an output encoder magnetic ring. The end of the center tube is fixed with an output shaft sleeve connected to the output encoder magnetic ring to measure the rotation speed of the output disk in real time. The end of the rotor is fixed with an input shaft sleeve connected to the input encoder magnetic ring to measure the rotation speed of the rotor in real time.

[0012] Furthermore, a heat sink is provided at the end of the outer wall of the pin housing to dissipate heat for the frameless torque motor.

[0013] Furthermore, the input encoder magnetic ring is sleeved outside the output encoder magnetic ring.

[0014] Furthermore, the two cycloid gears have a phase difference of 180° during rotation.

[0015] Furthermore, the inner end of the stator is limited by a prefabricated stepped surface at a corresponding position of the inner wall of the pin housing, an annular groove is provided on the outer edge of the stator and a support ring is mounted thereon, and the support ring is limited by pressing the end cover.

[0016] Furthermore, bearings are respectively arranged between the rotor and the inner hole of the end cover, between the head end of the outer wall of the eccentric shaft and the output disk, and between the outer side of the pin fixing disk and the prefabricated convex ring in the middle of the inner wall of the gear pin housing for connection and support.

[0017] Furthermore, a shaft spacer ring is arranged between the eccentric shaft and a bearing connected and supported with the output disc.

[0018] Furthermore, an inner spacer is arranged between the two cycloid gears, and outer spacers are arranged between the two cycloid gears and the output disk and the pin fixing disk, respectively.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention integrates and optimizes the frameless torque motor, cycloid reducer, and PCB board, with a compact structure. The central tube is used to realize the internal wiring of the joint, so that the line can go out from the head end of the joint, solving the wiring problem at the joint of the humanoid robot. While completing the basic motion function, it is more convenient to be applied to the humanoid robot;

[0021] 3. The present invention arranges the input and output encoders at the inner side of the PCB board at the end of the joint at the same time, and can realize high-precision position control by measuring the motor input speed and the output speed after deceleration by the cycloid reducer respectively. In addition, this arrangement of the encoders leaves more space on the PCB board for configuring other sensors and other equipment;

[0022] 4. The cycloid reducer in the joint of the present invention converts sliding friction into rolling friction by replacing all contact parts of the cycloid gear with needle bearing structures, which can reduce wear and run more smoothly, and has higher efficiency than traditional cycloid reducers;

[0023] 5. The structural form of the joint of the present invention has good transparency. When the output disk of the joint is impacted by the outside world, the force can be transmitted to the frameless torque motor part, thereby reducing the risk of damage to the cycloid reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an axonometric diagram of the overall structure of the cycloid joint of the present invention;

[0025] Figure 2 It is an exploded view of the overall structure of the cycloid joint of the present invention;

[0026] Figure 3 is a sectional view of the overall structure of the cycloid joint of the present invention;

[0027] Figure 4 is an axonometric schematic diagram of a cycloid gear in a cycloid joint of the present invention;

[0028] Figure 5 is an axonometric schematic diagram of a cycloid reducer in a cycloid joint of the present invention;

[0029] Figure 6 It is an exploded view of the frameless torque motor in the cycloid joint of the present invention.

[0030] In the figure: 11, output plate; 12, center tube; 13, pin fixing plate; 14, output shaft sleeve; 15, input shaft sleeve; 16, head end cover; 17, gear needle housing; 18, first set screw; 19, second set screw; 2, cycloid reducer; 201, eccentric shaft; 202, needle roller; 203, first cycloid gear; 203A, first bearing through hole; 204, second cycloid gear; 204A, second bearing through hole; 20 5. First needle roller bearing; 206. Output pin shaft; 207. Shaft spacer ring; 208. Outer spacer ring; 209. Inner spacer ring; 210. Cylindrical pin; 211. Second needle roller bearing; 3. Frameless torque motor; 31. Stator; 32. Rotor; 33. Support ring; 34. Washer; 35. End cover; 36. Keyway transmission mechanism; 37. Positioning pin; 4. PCB board; 41. Input encoder magnetic ring; 42. Output encoder magnetic ring. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] like Figure 1 to Figure 6 As shown, a high-performance cycloid joint is assembled and combined with Figure 1 As shown, it includes five parts: a housing part, an output transmission part, a cycloid reducer 2, a frameless torque motor 3 and a PCB board 4.

[0033] Combination Figure 2 As shown, the housing portion includes a pin housing 17, a head end cover 16 and an end cover 35. The pin housing 17 is a cylindrical structure, and the first and second ends of the pin housing are used to load the cycloid reducer 2 and the frameless torque motor 3, respectively. A heat sink can be provided at the end of the outer wall of the pin housing 17 to dissipate heat for the frameless torque motor 3. The head end cover 16 and the end cover 35 are both annular structures, fixed to the first and second ends of the pin housing 17 by screws, and are used to package and position the cycloid reducer 2 and the frameless torque motor 3, respectively.

[0034] Combination Figure 2-3 , Figure 6As shown, the frameless torque motor 3 includes a stator 31 and a rotor 32. The stator 31 is coaxially inserted into the end of the pin housing 17. The outer wall of the stator 31 is circumferentially positioned with the pin housing 17 by a positioning pin 37. The inner end of the stator 31 is limited by a prefabricated stepped surface at a corresponding position of the inner wall of the pin housing 17. The outer end of the stator 31 is limited by a press-fit end cover 35. An annular groove can be set on the edge of the outer end of the stator 31 and a support ring 33 can be set. A gasket 34 is installed between the end cover 35 and the pin housing 17, so that the support ring 33 can better press the stator 31 when tightening the screws of the end cover 35. The rotor 32 is coaxially arranged inside the stator 31 with clearance fit. The rotor 32 is connected and supported by a bearing and the inner hole of the end cover 35. When the frameless torque motor 3 is started, the rotor 32 rotates to provide power input for the joint.

[0035] Combination Figure 3 As shown, the output transmission part includes an output disk 11, a center tube 12 and a pin fixing disk 13. The center tube 12 is coaxially arranged inside the pin housing 17, so that the wire can be connected to the frameless torque motor 3 and the PCB board 4 through the center tube 12. The rear half of the center tube 12 extends into the center hole of the rotor 32 and is rotatably connected to it through a bearing. The output disk 11 is rotatably installed in the inner hole of the head end cover 16 through a bearing. The head end of the center tube 12 extends out through a preset through hole in the center of the output disk 11 and is expanded with a flange plate to be fixed to it by screws. The pin fixing disk 13 is arranged inside the pin housing 17 between the cycloid reducer 2 and the frameless torque motor 3, and is a symmetrical structure with the output disk 11, and is used for loading the output pin 206 in the subsequent cycloid reducer 2.

[0036] Combination Figure 2 to Figure 5As shown, the cycloid reducer 2 includes an eccentric shaft 201, a first cycloid gear 203, a second cycloid gear 204, a plurality of output pins 206 and a plurality of cylindrical pins 210. The eccentric shaft 201 is hollow and sleeved on the front half of the central tube 12, and is connected and driven with the rotor 32 through a keyway transmission mechanism 36. The head end of the outer wall of the eccentric shaft 201 is connected and supported with the output disk 11 through a bearing, two eccentric annular grooves are arranged in the middle of the outer wall of the eccentric shaft 201, the end of the outer wall of the eccentric shaft 201 is connected and supported with a through hole preset in the center of the pin fixing disk 13 through a bearing, and the outer side of the pin fixing disk 13 is connected and supported with the annular surface of the prefabricated convex ring in the middle of the inner wall of the pin housing 17 through a bearing. The first cycloid gear 203 and the second cycloid gear 204 have the same configuration. The middle holes of the first cycloid gear 203 and the second cycloid gear 204 are respectively mounted on the two eccentric annular grooves of the eccentric shaft 201, and a circle of needle rollers 202 are respectively arranged in the two eccentric annular grooves. The first cycloid gear 203 is located between the middle hole and the edge tooth profile and a plurality of first bearing through holes 203A are evenly arranged along the circumference, and the second cycloid gear 204 is located between the middle hole and the edge tooth profile and a plurality of second bearing through holes 204A are evenly arranged along the circumference. The first cycloid gear 203 and the second cycloid gear 204 are 180° out of phase during rotation, which offsets the impact to a certain extent. The plurality of output pins 206 are evenly inserted between the pin holes opened on the edge of the output disk 11 and the pin fixing disk 13 along the circumference, and the middle sections of the plurality of output pins 206 are respectively mounted with first needle roller bearings 205 and pass through the corresponding first bearing through hole 203A and the second bearing through hole 204A. The plurality of cylindrical pins 210 are inserted uniformly along the circumferential direction between the pin holes opened on the edge of the prefabricated convex ring in the middle of the inner wall of the pin housing 17, and the middle sections of the plurality of cylindrical pins 210 are respectively covered with the second needle roller bearings 211 and contact and cooperate with the edge tooth profiles of the first cycloid gear 203 and the second cycloid gear 204. In addition, in order to maintain the axial spacing, an axial spacer ring 207 is provided between the eccentric shaft 201 and the bearing connected and supported by the output disk 11, an inner spacer ring 209 is provided between the first cycloid gear 203 and the second cycloid gear 204, and an outer spacer ring 208 is provided between the first cycloid gear 203 and the output disk 11 and between the second cycloid gear 204 and the pin shaft fixing disk 13.

[0037] Combination Figure 2 , Figure 3As shown, the PCB board 4 is coaxially fixed to the outside of the end cover 35, and the PCB board 4 integrates a motor driver, a host computer communication module, a control module and a sensor, etc. An input encoder magnetic ring 41 and an output encoder magnetic ring 42 are connected to the inside of the PCB board 4, and the input encoder magnetic ring 41 is sleeved on the outside of the output encoder magnetic ring 42. The output shaft sleeve 14 is fixedly installed at the end of the center tube 12 by the first set screw 18, and the output shaft sleeve 14 is connected and fixed with the output encoder magnetic ring 42. The output encoder magnetic ring 42 is driven to rotate by the center tube 12, and the data is read by the PCB board 4 to measure the speed of the output disk 11 in real time, that is, the joint output speed; the input shaft sleeve 15 is fixedly installed at the end of the rotor 32 by the second set screw 19, and the input shaft sleeve 15 is connected and fixed with the input encoder magnetic ring 41. The input encoder magnetic ring 41 is driven to rotate by the rotor 32, and the data is read by the PCB board 4 to measure the speed of the rotor 32 in real time, that is, the motor input speed.

[0038] The high-performance cycloid joint of the present invention can be obtained through the above design. The frameless torque motor 3 occupies a small space and has a high degree of designability. When working, the PCB board 4 sends a signal to the frameless torque motor 3, and the rotor 32 drives the eccentric shaft 201 to rotate synchronously through the keyway transmission mechanism 36. Due to the characteristics of the edge tooth profile curves of the first cycloid gear 203 and the second cycloid gear 204, the first cycloid gear 203 and the second cycloid gear 204 are restricted by the second needle roller bearings 211 on the multiple cylindrical pins 210. The first cycloid gear 203 and the second cycloid gear 204 perform both orbital and rotational movements. When the rotor 32 rotates one circle, the eccentric shaft 201 also rotates one circle, and the first cycloid gear 203 and the second cycloid gear 204 rotate one tooth in the opposite direction to reduce speed, and then transmit to the output disk 11 for rotation through the first needle roller bearings 205 on the multiple output pin shafts 206, thereby obtaining a lower output speed and a larger torque, which has the advantages of high efficiency, high torque, stability, high precision and long life.

[0039] The high-performance cycloid joint of the present invention is provided with a needle roller 202 between the first cycloid gear 203, the second cycloid gear 204 and the eccentric shaft 201, so that the first cycloid gear 203 and the second cycloid gear 204 can be regarded as the outer ring of the needle roller bearing structure, the eccentric shaft 201 can be regarded as the inner ring of the needle roller bearing structure, and the whole can be regarded as a needle roller bearing structure. By providing the needle roller bearing structure at the contact part of the first cycloid gear 203 and the second cycloid gear 204, including the needle roller 202, the first needle roller bearing 205, and the second needle roller bearing 211, the sliding friction is converted into Rolling friction can reduce wear, and the reduction of friction also makes the joint more transparent. When the output disk 11 of the joint is impacted by the outside world, it can transfer force to the frameless torque motor 3, reducing the risk of damage to the cycloid reducer. For example, when the robot jumps and falls to the ground, the leg joints of the robot will be greatly impacted. At this time, due to the smaller friction, the impact force on the output disk 11 can be quickly reversed on the rotor 32 through the cycloid reducer 2, so that the robot can be controlled to land smoothly by controlling the torque of the frameless torque motor 3. In addition, the eccentric shaft 201 and the center tube 12 are both hollow structures, which facilitates the wire to be connected to the frameless torque motor 3 and the PCB board 4 through the center of the joint.

[0040] Compared with a modular robot joint disclosed in the Chinese authorized invention patent with publication number CN114043523B previously applied by the inventor team of this application, the rotational motion of the frameless torque motor is transmitted to the planetary carrier of the planetary gear train through the sun gear of the planetary gear train, and then the planetary carrier drives the crankshaft to move, and then outputs the rotational motion of the needle roller shell through the cycloid gear. In comparison, the high-performance cycloid joint of the present invention is:

[0041] 1. The keyway transmission mechanism 36 is directly used to drive the eccentric shaft 201 to rotate, and the eccentric shaft 201 drives the first cycloid gear 203 and the second cycloid gear 204 to rotate. The first cycloid gear 203 and the second cycloid gear 204 drive the output disk 11 to rotate through the first needle bearings 205 on the multiple output pins 206. The power is not transmitted through the planetary gear reducer, which improves the transparency and efficiency of the system;

[0042] 2. The output mode is different. The prior application uses the roller shell of the cycloid reducer as the output, while the present invention uses the output disk 11 as the output. Such torque transmission increases the reliability and stability of the transmission and can meet the requirements of greater torque. While meeting the same torque, the thickness of the first cycloid gear 203 and the second cycloid gear 204 of the present invention can be smaller, and the overall structure is more compact.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high performance cycloid joint, characterized in that: It comprises a housing part, an output transmission part, a cycloid reducer (2), a frameless torque motor (3) and a PCB board (4); The housing portion comprises a pin housing (17), a head end cover (16) and a tail end cover (35); the pin housing (17) is a cylindrical structure; the head end cover (16) and the tail end cover (35) are annular structures and are respectively fixed at the head and tail ends of the pin housing (17); The frameless torque motor (3) comprises a stator (31) and a rotor (32); the stator (31) is coaxially limitedly inserted inside the end of the pin housing (17); and the rotor (32) is coaxially clearance-fittedly arranged inside the stator (31); The cycloid reducer (2) is installed inside the head end of the pin gear housing (17), and comprises an eccentric shaft (201), two cycloid gears, a plurality of output pins (206) and a plurality of cylindrical pins (210); the eccentric shaft (201) is directly connected to the rotor (32) for transmission; a circle of needle rollers (202) is respectively arranged between the two cycloid gears and the eccentric shaft (201); the plurality of output pins (206) are uniformly inserted between the output disk (11) and the pin shaft fixing disk (13) along the circumferential direction; the middle section of the output pin (206) is sleeved with a first needle roller bearing (205) and passes through the bearing through holes correspondingly arranged on the two cycloid gears; the plurality of cylindrical pins (210) are uniformly inserted between the head end cover (16) and the middle prefabricated convex ring on the inner wall of the pin gear housing (17) along the circumferential direction; the middle section of the cylindrical pin (210) is sleeved with a second needle roller bearing (211) and contacts and cooperates with the tooth profiles of the two cycloid gears; The output transmission part comprises an output disk (11), a center tube (12) and a pin fixing disk (13); the center tube (12) is coaxially arranged inside a pin housing (17); the eccentric shaft (201) is hollowly arranged and sleeved on a front half of the center tube (12); the rear half of the center tube (12) extends into a center hole of a rotor (32) and is rotatably connected thereto; the output disk (11) is rotatably mounted in an inner hole of a head end cover (16); the head end of the center tube (12) extends out through a through hole preset in the center of the output disk (11) and is connected and fixed thereto; the through hole preset in the center of the pin fixing disk (13) is connected and supported by an outer wall end of the eccentric shaft (201) via a bearing; An input encoder magnetic ring (41) and an output encoder magnetic ring (42) are connected to the inner side of the PCB board (4); an output shaft sleeve (14) is fixed at the end of the central tube (12) and connected to the output encoder magnetic ring (42) to measure the rotation speed of the output disk (11) in real time; and an input shaft sleeve (15) is fixed at the end of the rotor (32) and connected to the input encoder magnetic ring (41) to measure the rotation speed of the rotor (32) in real time.

2. A high performance cycloid joint according to claim 1, characterized in that: A heat sink is arranged at the end of the outer wall of the pin housing (17) to dissipate heat for the frameless torque motor (3).

3. A high performance cycloid joint according to claim 1 or 2, characterized in that: The input encoder magnetic ring (41) is sleeved outside the output encoder magnetic ring (42).

4. A high performance cycloid joint according to claim 1, characterized in that: The two cycloid gears have a phase difference of 180° during rotation.

5. A high performance cycloid joint according to claim 1, characterized in that: The inner end of the stator (31) is limited by a prefabricated stepped surface at a corresponding position of the inner wall of the pin housing (17); an annular groove is provided on the outer edge of the stator (31) and a support ring (33) is mounted thereon; the support ring (33) is limited by a press-fitting end cover (35).

6. A high performance cycloid joint according to claim 1, characterized in that: Bearings are provided between the rotor (32) and the inner hole of the end cover (35), between the head end of the outer wall of the eccentric shaft (201) and the output disk (11), and between the outer side of the pin fixing disk (13) and the prefabricated convex ring in the middle of the inner wall of the pin housing (17) for connection and support.

7. A high performance cycloid joint according to claim 6, characterized in that: A shaft spacer ring (207) is arranged between the eccentric shaft (201) and a bearing connected and supported with the output disc (11).

8. A high performance cycloid joint according to claim 1, characterized in that: An inner spacer (209) is arranged between the two cycloid gears, and outer spacers (208) are arranged respectively between the two cycloid gears and the output disk (11) and the pin shaft fixing disk (13).

Images