RV speed reducer for robot

Abstract

The RV speed reducer for the robot comprises an input shaft, a planetary gear mechanism, a crankshaft, a pin wheel housing, a housing, an output disc and a pre-tightening adjusting mechanism, the planetary gear mechanism is arranged at the output end of the input shaft, the input end of the input shaft is connected with a driving motor, and the pin wheel housing is connected with the driving motor. The crankshaft is driven by the planetary gear mechanism to rotate, eccentric parts are arranged on the two sides of the crankshaft, cycloidal gears are symmetrically arranged on the two eccentric parts, cycloidal teeth subjected to bidirectional modification are arranged on the peripheries of the cycloidal gears, the pin wheel shell is arranged on the inner side of the shell, and a plurality of circles of pin teeth are arranged on the inner periphery of the pin wheel shell. According to the RV speed reducer, by optimizing cycloidal gear tooth shape modification parameters (0.02-0.04 mm bidirectional modification) and pin gear non-uniform distribution design, the contact stress peak value is remarkably reduced; a pre-tightening adjusting mechanism is adopted to dynamically compensate the meshing clearance, so that the return difference is stabilized within one arc minute; and the planetary gear adopts a 1: 3 high reduction ratio design, so that a compact structure is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of robot joints, and in particular to an RV reducer for a robot. Background Art

[0002] RV reducer (also known as planetary cycloidal pinwheel reducer) is mainly composed of a primary planetary gear transmission and a secondary cycloidal pinwheel transmission. It is a new type of cycloidal pinwheel planetary transmission reducer. RV reducers are mostly used in the joints of industrial robots. The loads they bear during operation are usually large, which puts high demands on the rigidity, impact resistance, wear resistance, life and other performance of RV reducers.

[0003] Common RV reducers on the market generally have the following problems:

[0004] 1. The tooth shape of traditional cycloid gears is not optimized, which easily leads to stress concentration and insufficient service life;

[0005] 2. The meshing clearance between the needle teeth and the cycloid teeth cannot be adjusted, and the hysteresis increases after long-term wear;

[0006] 3. The unreasonable design of the planetary gear transmission ratio affects the miniaturization of the reducer;

[0007] 4. The coaxiality error of the input and output shafts is large, which affects the robot's motion accuracy.

[0008] Therefore, it is necessary to design an RV reducer with high precision, dynamically adjustable meshing clearance and low vibration. Summary of the invention

[0009] In view of the technical defects existing in the background technology, the present invention proposes an RV reducer for a robot, which solves the above technical problems and meets the actual needs. The specific technical solution is as follows:

[0010] A RV reducer for a robot comprises: an input shaft, a planetary gear mechanism, a crankshaft, a pinion gear housing, a housing, an output disc and a preload adjustment mechanism, wherein the planetary gear mechanism is arranged at the output end of the input shaft, the input end of the input shaft is connected to a driving motor, the crankshaft is driven to rotate by the planetary gear mechanism and is provided with eccentric parts on both sides, the two eccentric parts are symmetrically provided with cycloid wheels, the outer periphery of the cycloid wheel is provided with cycloid teeth that have been modified in both directions, the pinion gear housing is arranged on the inner side of the housing and is provided with a plurality of circles of pinion teeth on the inner periphery, the output disc is connected to the cycloid wheel through an involute spline, the preload adjustment mechanism comprises a butterfly spring group and an adjusting bolt, which are used to adjust the meshing clearance between the pinion teeth and the cycloid teeth, the modification amount & of the cycloid teeth satisfies: 0.02mm≤&≤0.04mm, and the modification direction comprises tooth root modification and tooth top modification.

[0011] Furthermore, the tooth number ratio of the sun gear to the planetary gear in the planetary gear mechanism is 1:3, and the module is 0.6mm-1mm.

[0012] Furthermore, it also includes a magnetic fluid sealing ring, which is arranged in the gap between the output disk and the shell.

[0013] Furthermore, the input shaft is a hollow structure with a keyway provided on the inner wall for passing cables or air pipes through the robot joints.

[0014] Furthermore, the tooth top modification amount &1 and the tooth root modification amount &2 of the cycloid tooth satisfy: &1 / &2=1.2-1.5.

[0015] Furthermore, the shell is made of carbon fiber reinforced aluminum alloy material, and the volume fraction of carbon fiber is 15%-25%.

[0016] Furthermore, it also includes a temperature sensor and a vibration sensor, which are embedded in the inner wall of the pinion housing and are used to monitor the operating status of the reducer in real time.

[0017] Furthermore, the distribution density of the needle teeth is increased by 15-25% in the area of ​​maximum meshing stress of the cycloid wheel, and is equidistantly distributed in the remaining areas.

[0018] Furthermore, the diameter of the needle teeth in the maximum stress area is 0.05-0.1 mm larger than that in other areas.

[0019] Furthermore, the magnetic fluid material of the magnetic fluid sealing ring is Fe3O4-based nanofluid, and the magnetic induction intensity is 0.3-0.5T.

[0020] Compared with the prior art, the RV reducer for a robot provided by the present invention has the following beneficial effects:

[0021] The present invention discloses an RV reducer for robots, which significantly reduces the contact stress peak value by optimizing the cycloid gear tooth modification parameters (0.02-0.04mm bidirectional modification) and the non-uniform distribution design of the pin teeth; a preload adjustment mechanism is used to dynamically compensate the meshing clearance, so that the backlash is stabilized within 1 arc minute; and a 1:3 high reduction ratio design is used for the planetary gear to achieve a compact structure. The reducer has high precision (coaxiality error ≤ 0.008mm), long life (≥ 15,000 hours) and low vibration characteristics, and is suitable for the joints of six-axis industrial robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an RV reducer for a robot in the present invention.

[0023] Figure 2 This is a schematic diagram of the internal structure of an RV reducer for a robot in the present invention.

[0024] Figure 3 It is a schematic diagram of the structure of the shell in the present invention.

[0025] Figure 4 It is a schematic diagram of the connection between the crankshaft and the planetary gear mechanism in the present invention.

[0026] Figure 5 This is a schematic diagram of the bottom structure of an RV reducer for a robot in the present invention.

[0027] Among them, 1. input shaft, 2. planetary gear mechanism, 3. crankshaft, 4. pinion housing, 5. housing, 6. output disc, 7. preload adjustment mechanism, 8. eccentric part, 9. cycloid wheel, 10. cycloid tooth, 11. involute spline, 12. sun gear, 13. planetary gear, 14. magnetic fluid sealing ring, 15. keyway. DETAILED DESCRIPTION

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "middle", "inside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0029] The implementation modes of the present invention are described below in conjunction with the accompanying drawings and relevant embodiments. The implementation modes of the present invention are not limited to the following embodiments, and the present invention relates to relevant necessary components in the technical field, which should be regarded as the known technology in the technical field and can be known and mastered by the technical personnel in the technical field.

[0030] See also Figure 1-5, an RV reducer for a robot, comprising: an input shaft 1, a planetary gear mechanism 2, a crank shaft 3, a pinion housing 4, a housing 5, an output disk 6 and a preload adjustment mechanism 7, wherein the planetary gear mechanism 2 is arranged at the output end of the input shaft 1, and the input end of the input shaft 1 is connected to a driving motor, the crank shaft 3 is driven to rotate by the planetary gear mechanism 2 and is provided with eccentric parts 8 on both sides, the two eccentric parts 8 are symmetrically provided with cycloid wheels 8, the outer periphery of the cycloid wheel 8 is provided with cycloid teeth 10 that have been modified in both directions, the pinion housing 4 is arranged on the inner side of the housing 5 and is provided with a plurality of circles of pinions on the inner periphery, the output disk 6 is connected to the cycloid wheel 8 through an involute spline 11, and the preload adjustment mechanism 7 comprises a butterfly spring group and an adjusting bolt for adjusting the meshing clearance between the pinion teeth and the cycloid teeth 10, and the prior art mostly adopts static adjustment with gaskets, which cannot dynamically adapt to wear. Dynamic compensation of meshing clearance can be achieved through butterfly spring group and adjusting bolt, and the backlash is stably controlled at ≤1 arc minute. The backlash of traditional fixed clearance design can reach 2-3 arc minutes after wear; the preload force can be adjusted without disassembly, and the maintenance cost is reduced by 60%. The shaping amount of the cycloid tooth 10 meets the following requirements: 0.02mm≤&≤0.04mm, and the shaping direction includes root shaping and tooth top shaping. The use of two-way shaping of tooth top and tooth root and limiting the shaping amount range can reduce stress concentration on the tooth surface, increase the service life to 15,000 hours, reduce meshing impact noise, and reduce vibration amplitude by 42%.

[0031] In one embodiment of the present invention, the gear ratio of the sun gear 12 and the planetary gear 13 in the planetary gear mechanism 2 is 1:3, and the module is 0.6mm-1mm. The reduction ratio is increased to 30-50:1 at the same volume, and the structure is compact and suitable for miniaturized robot joints.

[0032] In one embodiment of the present invention, a magnetic fluid sealing ring 14 is further included, and the magnetic fluid sealing ring 14 is disposed at the gap between the output disk 6 and the housing 5. The sealing life of a conventional rubber seal is about 2-3 years, but after using the magnetic fluid sealing ring 14, the sealing life is extended to more than 5 years, and the magnetic fluid sealing ring 14 is resistant to high temperatures and can be applied to robots in extreme environments.

[0033] In one embodiment of the present invention, the input shaft 1 is a hollow structure, and a keyway 15 is provided on the inner wall for cables or gas pipelines passing through the robot joints. The hollow input shaft 1 reduces the robot joint wiring space by 40%, and is suitable for the narrow joint cavity of the collaborative robot.

[0034] In one embodiment of the present invention, the tooth top modification amount &1 and the tooth root modification amount &2 of the cycloid tooth 10 satisfy: &1 / &2=1.2-1.5.

[0035] In one embodiment of the present invention, the housing 5 is made of carbon fiber reinforced aluminum alloy material, and the volume fraction of carbon fiber is 15%-25%. Lightweight and high rigidity are combined to reduce the inertia of robot joints.

[0036] In one embodiment of the present invention, a temperature sensor and a vibration sensor are also included, which are embedded in the inner wall of the pin gear housing 4 and used to monitor the operating state of the reducer in real time. The temperature sensor and vibration sensor can be intelligently monitored to achieve predictive monitoring.

[0037] In one embodiment of the present invention, the distribution density of the needle teeth is increased by 15-25% in the maximum meshing stress area of ​​the cycloid wheel 8, and is equidistantly distributed in the remaining areas.

[0038] In one embodiment of the present invention, the diameter of the needle teeth in the maximum stress area is 0.05-0.1 mm larger than that in the remaining areas.

[0039] In one embodiment of the present invention, the magnetic fluid material of the magnetic fluid sealing ring 14 is Fe3O4-based nanofluid, and the magnetic induction intensity is 0.3-0.5T.

[0040] The present invention discloses an RV reducer for robots. The cycloid wheel 8 is optimized for tooth modification parameters (0.02-0.04mm), bidirectional modification, and non-uniform distribution of pin teeth, which significantly reduces the contact stress peak value. The preload adjustment mechanism 7 is used to dynamically compensate the meshing clearance, so that the backlash is stabilized within 1 arc minute. The planetary gear adopts a 1:3 high reduction ratio design to achieve a compact structure. The reducer has high precision (coaxiality error ≤ 0.008mm), long life (≥ 15,000 hours), and low vibration characteristics, and is suitable for the joints of six-axis industrial robots.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An RV reducer for a robot, characterized in that: include: An input shaft (1), a planetary gear mechanism (2), a crankshaft (3), a pinion housing (4), a housing (5), an output disc (6) and a preload adjustment mechanism (7), wherein the planetary gear mechanism (2) is arranged at the output end of the input shaft (1), the input end of the input shaft (1) is connected to a drive motor, the crankshaft (3) is driven to rotate by the planetary gear mechanism (2) and has eccentric parts (8) on both sides, the two eccentric parts (8) are symmetrically provided with cycloid wheels (8), and the outer periphery of the cycloid wheels (8) is provided with A cycloid tooth (10) is provided which has been subjected to bidirectional shaping. The pin tooth housing (4) is arranged on the inner side of a housing (5) and has a plurality of circles of pin teeth on the inner circumference. The output disc (6) is connected to a cycloid wheel (8) via an involute spline (11). The preload adjustment mechanism (7) comprises a butterfly spring assembly and an adjusting bolt for adjusting the meshing clearance between the pin teeth and the cycloid tooth (10). The shaping amount & of the cycloid tooth (10) satisfies: 0.02 mm ≤ & ≤ 0.04 mm, and the shaping direction comprises tooth root shaping and tooth top shaping.

2. The RV reducer for a robot according to claim 1, characterized in that: The gear ratio between the sun gear (12) and the planet gear (13) in the planetary gear mechanism (2) is 1:3, and the module is 0.6 mm-1 mm.

3. The RV reducer for a robot according to claim 1, characterized in that: It also comprises a magnetic fluid sealing ring (14), wherein the magnetic fluid sealing ring (14) is arranged at the gap between the output disk (6) and the housing (5).

4. The RV reducer for a robot according to claim 1, characterized in that: The input shaft (1) is a hollow structure, and a keyway (15) is provided on the inner wall thereof for a cable or an air pipeline passing through a robot joint.

5. The RV reducer for a robot according to claim 1, characterized in that: The tooth top modification amount &1 and the tooth root modification amount &2 of the cycloid tooth (10) satisfy: &1 / &2=1.2-1.

5.

6. The RV reducer for a robot according to claim 1, characterized in that: The shell (5) is made of carbon fiber reinforced aluminum alloy material, and the volume fraction of carbon fiber is 15%-25%.

7. The RV reducer for a robot according to claim 1, characterized in that: It also includes a temperature sensor and a vibration sensor, which are embedded in the inner wall of the pin gear housing (4) and are used to monitor the operating status of the reducer in real time.

8. The RV reducer for a robot according to claim 1, characterized in that: The distribution density of the needle teeth increases by 15-25% in the maximum meshing stress area of ​​the cycloid wheel (8), and is equidistantly distributed in the remaining areas.

9. The RV reducer for a robot according to claim 8, characterized in that: The diameter of the needle teeth in the maximum stress area is 0.05-0.1 mm larger than that in the remaining areas.

10. The RV reducer for a robot according to claim 3, characterized in that: The magnetic fluid material of the magnetic fluid sealing ring (14) is Fe3O4-based nanofluid, and the magnetic induction intensity is 0.3-0.5T.

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