Low-return-difference cycloidal speed reducer for heavy industrial equipment

Abstract

The utility model discloses a low return difference cycloidal speed reducer for heavy industrial equipment, which comprises a needle shell, a bearing inner ring is arranged on the inner side of the needle shell, a rear planet carrier is arranged at the left end of the needle shell, a front planet carrier is arranged at the right end of the needle shell, and a hexagon socket cap screw is fixed between the rear planet carrier and the front planet carrier. A framework oil seal is arranged between the needle shell and the rear planet carrier, a speed reduction structure used for driving the rear planet carrier to rotate and output is arranged in the needle shell, an input gear shaft is arranged on the inner side of the rear planet carrier and the inner side of the front planet carrier, and a driving structure used for driving the speed reduction structure to rotate is arranged on the input gear shaft. According to the low-return-difference cycloidal speed reducer for the heavy industrial equipment, the needle shell and the external rack are installed and fixed, the input gear shaft is connected with an external power source, and therefore a speed reduction structure can drive the rear planet carrier to rotate and output stably.

Description

Technical Field

[0001] The utility model relates to the technical field of reducers, in particular to a low-backlash cycloid reducer for heavy industrial equipment. Background Art

[0002] The RV (rotor-vector) drive for robots (a crank-type closed differential gear train) is a new type of transmission developed based on the cycloid drive. Its key features are three advantages (high transmission ratio, high load capacity, and high rigidity), two highs (high motion precision and high transmission efficiency), and one small difference (low backlash). Compared to simple cycloid planetary drives, it boasts a smaller footprint and greater overload capacity, earning it widespread attention both domestically and internationally. In Japanese robot transmissions, it has largely replaced simple cycloid planetary drives and harmonic drives. The RV drive has two extremely stringent technical specifications: transmission error cannot exceed 1'; and backlash must not exceed 1' to 1.5', depending on the RV reducer model. Furthermore, when operating under rated load, the total backlash, including backlash caused by elastic deformation, cannot exceed 6'.

[0003] In this field, patented technologies such as the one described in Grant Publication No. CN115163757B describe a high-precision cycloid differential gear reducer, comprising an input gear shaft and a two-stage reduction mechanism. The two-stage reduction mechanism includes an internally meshing first-stage planetary reduction mechanism consisting of the input gear shaft and internal gear, and a second-stage two-tooth-difference cycloid pinwheel planetary reduction mechanism consisting of a double-piece cycloid gear, a pinion housing, a splined eccentric shaft assembly, pinions, and a planetary carrier. The reducer's inner and outer raceways are integrated with the components, reducing the reducer's size while maintaining the bearings' inherent load capacity. The bearings between the cycloid gear and eccentric sleeve, and between the planetary carrier and pinion housing, are assembled by inserting steel balls from either the inner or outer side of the components. This effectively and rationally increases the number of steel balls, further improving the bearing's support capacity and ensuring the overall rigidity and strength of the device. Given the high load capacity and high transmission accuracy of high-precision cycloid differential gear reducers for robots, designing a compact, high-precision, and low-cost RV reducer presents a significant challenge. Although the technology described in patent CN115163757B has made some innovations in bearing design and assembly, there is still room for improvement in further reducing backlash, improving transmission accuracy, and optimizing overall structural design. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the utility model provides a low-backlash cycloid reducer for heavy industrial equipment, which solves the problems of unreasonable reducer structure, low crankshaft strength and poor impact resistance.

[0005] In order to achieve the purpose of the above-mentioned reducer having a reasonable structure, high crankshaft strength and good impact resistance, the utility model provides the following technical solutions: a low backlash cycloid reducer for heavy industrial equipment, comprising a needle housing, a bearing inner ring being provided on the inner side of the needle housing, a rear planetary carrier being provided on the left end of the needle housing, a front planetary carrier being provided on the right end of the needle housing, a hexagonal cylindrical head screw being fixed between the rear planetary carrier and the front planetary carrier, a skeleton oil seal being provided between the needle housing and the rear planetary carrier, a reduction structure for driving the rear planetary carrier to rotate and output being provided inside the needle housing, an input gear shaft being provided on the inner side of the rear planetary carrier and the front planetary carrier, and a drive structure for driving the reduction structure to rotate being provided on the input gear shaft;

[0006] The drive structure includes planetary gears, inner washers, and inner tapered roller bearings. The planetary gears are provided in three groups, and the three groups of planetary gears are meshed with the input gear shaft. The surface of the input gear shaft is movably engaged with the inner washers. The inner tapered roller bearings are mounted on the input gear shaft and fixedly connected to the input gear shaft via the inner washers.

[0007] The deceleration structure includes a needle roller, a rear cycloid wheel, a front cycloid wheel, a steel retaining frame needle roller, an outer gasket, an outer tapered roller bearing, a retaining ring for a hole and an eccentric shaft. The planetary gear is mounted and fixed on the eccentric shaft. The needle roller is movably connected to the inner wall tooth groove of the needle housing. The needle roller is located between the needle housing and the rear cycloid wheel and the front cycloid wheel. The surface of the eccentric shaft is mounted with a steel retaining frame needle roller. The steel retaining frame needle roller is located inside the end face through hole of the rear cycloid wheel and the front cycloid wheel. The outer gasket is movably clamped on the eccentric shaft. The outer gasket is located on the outside of the steel retaining frame needle roller. Outer tapered roller bearings are mounted on both ends of the eccentric shaft. The outer tapered roller bearings are mounted and fixed on the eccentric shaft through retaining rings for a hole.

[0008] Preferably, the planetary gear has 61 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 12 mm.

[0009] Preferably, the input gear shaft has 17 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 18 mm.

[0010] Preferably, the eccentricity of the eccentric shaft is 2 mm.

[0011] Preferably, the number of teeth of the rear cycloid wheel and the front cycloid wheel is 39, the outer diameter of the needle gear sleeve is Φ8mm, the eccentricity is 2mm, the center circle diameter of the needle wheel is Φ220mm, and the tooth width is 18.9mm.

[0012] Preferably, the outer diameter of the needle roller is Φ8 mm and the length is 39.8 mm.

[0013] Preferably, the needle housing has 40 teeth, a center circle diameter of Φ220 mm, and a needle tooth diameter of Φ8 mm.

[0014] Compared with the existing technology, the utility model provides a low backlash cycloid reducer for heavy industrial equipment, which has the following beneficial effects:

[0015] This low-backlash cycloid reducer for heavy-duty industrial equipment features a rational structure. The cycloid gear utilizes a single-differential gear structure, resulting in superior meshing precision compared to double-differential gearing. The cycloid gear, needle roller, and needle housing all utilize rolling friction contact, resulting in excellent rigidity. The input shaft utilizes a double-support structure, ensuring stable transmission and low vibration. The single-differential gear meshing facilitates achieving high drive train error and backlash requirements, resulting in improved rigidity and reduced backlash, thus preventing jitter and excessive damping vibration during reducer operation. The planetary carrier utilizes a columnar taper pin connection structure, characterized by its simplicity, ease of machining, and high strength. Furthermore, the high-precision taper pin connection ensures consistent machining and assembly.

[0016] 2. This low-backlash cycloid reducer for heavy industrial equipment has the characteristics of reasonable structure, small size, high efficiency and low cost, which broadens the application scope of RV reducers. The advantages of this utility model are simplified structural design, convenient parts processing and manufacturing, and reduced costs. At the same time, it has the characteristics of high efficiency, light weight, stable operation, impact resistance, low noise, strong overload capacity and long life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural assembly diagram of a low backlash cycloid reducer for heavy industrial equipment described in the utility model;

[0018] Figure 2 This is a structural schematic diagram of a low-backlash cycloid reducer for heavy industrial equipment described in the utility model.

[0019] The symbols in the accompanying drawings are described as follows:

[0020] 1. Needle housing; 2. Bearing inner ring; 3. Rear planetary carrier; 4. Front planetary carrier; 5. Hexagon socket head screw; 6. Skeleton oil seal; 7. Needle roller; 8. Rear cycloid pulley; 9. Front cycloid pulley; 10. Needle roller with steel cage; 11. Outer gasket; 12. External tapered roller bearing; 13. Circlip for hole; 14. Eccentric shaft; 15. Planetary gear; 16. Inner gasket; 17. Internal tapered roller bearing; 18. Input gear shaft. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not 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 efforts are within the scope of protection of the present invention.

[0022] See also Figure 1-2 The utility model provides a low backlash cycloid reducer for heavy industrial equipment, including a needle housing 1, a bearing inner ring 2 is provided on the inner side of the needle housing 1, a rear planetary carrier 3 is provided on the left end of the needle housing 1, and a front planetary carrier 4 is provided on the right end of the needle housing 1. The left and right ends of the needle housing 1 are respectively rotatably connected with the rear planetary carrier 3 and the front planetary carrier 4 through the bearing inner ring 2, a hexagon socket cylindrical head screw 5 is fixed between the rear planetary carrier 3 and the front planetary carrier 4, and the rear planetary carrier 3 and the front planetary carrier 4 are fixedly connected through the hexagon socket cylindrical head screw 5, a skeleton oil seal 6 is provided between the needle housing 1 and the rear planetary carrier 3, a reduction structure for driving the rear planetary carrier 3 to rotate and output is provided inside the needle housing 1, an input gear shaft 18 is provided on the inner side of the rear planetary carrier 3 and the front planetary carrier 4, and a driving structure for driving the reduction structure to rotate is provided on the input gear shaft 18;

[0023] The drive structure includes planetary gears 15, inner washers 16, and inner tapered roller bearings 17. There are three sets of planetary gears 15, and the three sets of planetary gears 15 are meshed with the input gear shaft 18. The surface of the input gear shaft 18 is movably engaged with the inner washers 16. The inner tapered roller bearings 17 are mounted on the input gear shaft 18 and are fixedly connected to the input gear shaft 18 via the inner washers 16.

[0024] The reduction structure includes a needle roller 7, a rear cycloid wheel 8, a front cycloid wheel 9, a steel cage needle roller 10, an outer gasket 11, an outer tapered roller bearing 12, a hole retaining ring 13 and an eccentric shaft 14. The planetary gear 15 is fixed on the eccentric shaft 14. The needle roller 7 is movably connected to the inner wall tooth groove of the needle housing 1. The needle roller 7 is located between the needle housing 1 and the rear cycloid wheel 8 and the front cycloid wheel 9. The surface of the eccentric shaft 14 is installed with a steel cage needle roller 10. The steel cage needle roller 10 is located inside the end face through hole of the rear cycloid wheel 8 and the front cycloid wheel 9. The outer gasket 11 is movably clamped on the eccentric shaft 14. The outer gasket 11 is located on the outside of the steel cage needle roller 10. External tapered roller bearings 12 are installed at both ends of the eccentric shaft 14. The outer tapered roller bearing 12 is fixed on the eccentric shaft 14 with a retaining ring 13 through the hole. The reducer of this structure has two stages of reduction. The first stage is a planetary reduction mechanism, which mainly includes three planetary gears 15 and an input gear shaft 18. The second stage is a cycloid pinwheel planetary reduction mechanism, which mainly includes three eccentric shafts 14, two rear cycloid wheels 8 and a front cycloid wheel 9, a rear planetary carrier 3 and a front planetary carrier 4, forty needle rollers 7 and a needle shell 1. The two rear cycloid wheels 8 and the front cycloid wheel 9 and the needle shell 1 have differential teeth meshing to form a reduction, and the planetary carrier outputs. The two-stage reduction mechanism forms a planetary mechanism. The planetary mechanism directly designs the bearing inner ring 2 on the outer circle of the rear planetary carrier 3 and the front planetary carrier 4. The structure is compact and reduces the manufacturing difficulty.

[0025] Furthermore, the planetary gear 15 has 61 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 12 mm, which facilitates the engagement of the input gear shaft 18 with the three sets of planetary gears 15 to drive the three sets of eccentric shafts 14 to rotate.

[0026] Furthermore, the input gear shaft 18 has 17 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 18 mm. By connecting the input gear shaft 18 to an external power source, the input gear shaft 18 can be driven to rotate, and then the input gear shaft 18 can drive the three sets of planetary gears 15 to rotate.

[0027] Furthermore, the eccentric distance of the eccentric shaft 14 is 2 mm. During the eccentric rotation of the eccentric shaft 14, the steel cage needle roller 7 can stably drive the rear cycloid wheel 8 and the front cycloid wheel 9 to eccentrically swing during the rotation.

[0028] Furthermore, the number of teeth of the rear cycloid wheel 8 and the front cycloid wheel 9 is 39, the outer diameter of the needle gear sleeve is Φ8mm, the eccentricity is 2mm, the center circle diameter of the needle wheel is Φ220mm, and the tooth width is 18.9mm. When the rear cycloid wheel 8 and the front cycloid wheel 9 are deflected, the needle roller 7 and the inner wall tooth groove of the needle housing 1 are staggered and connected, thereby driving the rear planetary carrier 3 to output.

[0029] Furthermore, the outer diameter of the needle roller 7 is Φ8 mm and the length is 39.8 mm. When the rear cycloid wheel 8 and the front cycloid wheel 9 deflect, the needle roller 7 can be driven to rotate in the tooth groove of the inner wall of the needle housing 1.

[0030] Furthermore, the needle housing 1 has 40 teeth, a center circle diameter of Φ220 mm, and a needle tooth diameter of Φ8 mm. When the needle roller 7 is staggered with the inner wall tooth grooves of the needle housing 1, it can drive the rear planetary carrier 3 to rotate and output.

[0031] During use, the needle housing 1 is fixed to the external frame, and the input gear shaft 18 is connected to the external power source to drive the input gear shaft 18 to rotate, and then the input gear shaft 18 can drive the three sets of planetary gears 15 to rotate, and the planetary gears 15 can drive the eccentric shaft 14 to rotate eccentrically. In the process of eccentric rotation of the eccentric shaft 14, the outer tapered roller bearing 12 can be axially limited by the hole retaining ring 13, so that the outer tapered roller bearing 12 can support and rotate both ends of the eccentric shaft 14. The structure is compact, so that the eccentric shaft 14 can more stably drive the steel cage needle roller 10 to rotate. Thereby, the steel retainer needle roller 10 can stably drive the rear cycloid wheel 8 and the front cycloid wheel 9 to eccentrically swing during the rotation process, and when the rear cycloid wheel 8 and the front cycloid wheel 9 deflect, the needle roller 7 can be driven to rotate in the inner wall tooth groove of the needle shell 1, so that the needle roller 7 and the inner wall tooth groove of the needle shell 1 are staggered and connected, and the left and right ends of the eccentric shaft 14 are respectively connected to the end face through holes of the rear planetary carrier 3 and the front planetary carrier 4 through the steel retainer needle rollers 10 on both sides. Therefore, the eccentric shaft 14 can drive the rear planetary carrier 3 and the front planetary carrier 4 to rotate at the same time when rotating, so that the rear planetary carrier 3 can output with a larger torque.

[0032] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low backlash cycloid reducer for heavy industrial equipment, comprising a needle housing (1), characterized in that: A bearing inner ring (2) is provided on the inner side of the needle housing (1), a rear planetary carrier (3) is provided on the left end of the needle housing (1), and a front planetary carrier (4) is provided on the right end of the needle housing (1). The left and right ends of the needle housing (1) are rotatably connected to the rear planetary carrier (3) and the front planetary carrier (4) respectively through the bearing inner ring (2). A hexagon socket head screw (5) is fixed between the rear planetary carrier (3) and the front planetary carrier (4), and the rear planetary carrier (3) and the front planetary carrier (4) are fixedly connected through the hexagon socket head screw (5). A skeleton oil seal (6) is provided between the needle housing (1) and the rear planetary carrier (3). A reduction structure for driving the rear planetary carrier (3) to rotate and output is provided inside the needle housing (1). An input gear shaft (18) is provided on the inner side of the rear planetary carrier (3) and the front planetary carrier (4). A driving structure for driving the reduction structure to rotate is provided on the input gear shaft (18).

2. The low backlash cycloid reducer for heavy industrial equipment according to claim 1, characterized in that: The driving structure comprises a planetary gear (15), an inner gasket (16) and an inner tapered roller bearing (17); the planetary gear (15) is provided in three groups, and the three groups of planetary gears (15) are meshed with an input gear shaft (18); the surface of the input gear shaft (18) is movably engaged with the inner gasket (16); the inner tapered roller bearing (17) is mounted on the input gear shaft (18); and the inner tapered roller bearing (17) is fixedly connected to the input gear shaft (18) via the inner gasket (16).

3. The low backlash cycloid reducer for heavy industrial equipment according to claim 2, characterized in that: The deceleration structure comprises a needle roller (7), a rear cycloid wheel (8), a front cycloid wheel (9), a steel retaining frame needle roller (10), an outer gasket (11), an outer tapered roller bearing (12), a hole retaining ring (13) and an eccentric shaft (14); the planetary gear (15) is fixed on the eccentric shaft (14); the needle roller (7) is movably connected to the inner wall tooth groove of the needle housing (1); the needle roller (7) is located between the needle housing (1) and the rear cycloid wheel (8) and the front cycloid wheel (9); the surface of the eccentric shaft (14) is installed with a steel retaining frame needle roller (10); the steel retaining frame needle roller (10) is located inside the end surface through holes of the rear cycloid wheel (8) and the front cycloid wheel (9).

4. The low backlash cycloid reducer for heavy industrial equipment according to claim 3, characterized in that: The outer gasket (11) is movably connected to the eccentric shaft (14), and the outer gasket (11) is located outside the steel retaining needle roller (10). External tapered roller bearings (12) are installed at both ends of the eccentric shaft (14), and the external tapered roller bearings (12) are fixed to the eccentric shaft (14) through a retaining ring (13) through a hole.

5. The low backlash cycloid reducer for heavy industrial equipment according to claim 2, characterized in that: The planetary gear (15) has 61 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 12 mm.

6. The low backlash cycloid reducer for heavy industrial equipment according to claim 1, characterized in that: The input gear shaft (18) has 17 teeth, a module of 1.5, a pressure angle of 20°, and a tooth width of 18 mm.

7. The low backlash cycloid reducer for heavy industrial equipment according to claim 3, characterized in that: The eccentricity of the eccentric shaft (14) is 2 mm.

8. The low backlash cycloid reducer for heavy industrial equipment according to claim 3, characterized in that: The number of teeth of the rear cycloid wheel (8) and the front cycloid wheel (9) is 39, the outer diameter of the needle tooth sleeve is Φ8mm, the eccentricity is 2mm, the diameter of the needle wheel center circle is Φ220mm, and the tooth width is 18.9mm.

9. The low backlash cycloid reducer for heavy industrial equipment according to claim 3, characterized in that: The outer diameter of the needle roller (7) is Φ8 mm and the length is 39.8 mm.

10. The low backlash cycloid reducer for heavy industrial equipment according to claim 1, characterized in that: The needle housing (1) has 40 teeth, a center circle diameter of Φ220 mm, and a needle tooth diameter of Φ8 mm.

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