Power dividing planetary harmonic reducer

Abstract

The invention discloses a power dividing planetary harmonic reducer, which belongs to the technical field of reducers and comprises an input shaft, the input shaft is fixedly connected with a wave generator, the outer side of the wave generator is covered with a flexible gear, the outer gear ring end of the flexible gear is meshed with a steel wheel inner gear ring of a steel wheel, the steel wheel outer gear ring of the steel wheel is meshed with a planet wheel, and the planet wheel is arranged on a planet carrier. A rigid inner gear ring is meshed with the outer periphery of the planet wheel; an output shell is rotatably arranged at the shaft end of the planet carrier; the cylinder end of the flexible gear is fixedly connected with an output shaft, and the output shaft is located in the center of the output shell. Through the harmonic differential gear train, the transmitted torque can be increased in a mode of power shunting and joint output of the flexible gear and the planet carrier, machining is convenient, assembling is easy, the whole machine structure is compact, the transmission ratio is increased, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a power split planetary harmonic reducer. Background Art

[0002] Planetary transmission has the advantages of strong load-bearing capacity, compact structure, and strong adaptability. It is widely used in various engineering machinery such as wind power generation, aviation, and automobiles. However, single-stage planetary transmission has the problem of small transmission ratio; harmonic transmission is a kind of high-torque transmission that uses elastic deformation. It has the advantages of large transmission ratio, high transmission accuracy, and small size. It is widely used in precision machinery fields such as industrial robots, collaborative robots, and aerospace. However, due to the thin-walled characteristics of the flexible wheel, harmonic transmission has the problems of insufficient rigidity and weak load-bearing capacity. Therefore, the planetary harmonic transmission that combines planetary transmission and harmonic transmission has overcome the problems of single-stage planetary transmission and single-stage harmonic transmission and has received extensive research in recent years.

[0003] Publication No. CN110307299B discloses a planetary harmonic combination reducer, which is composed of a planetary drive and a harmonic drive connected in series, wherein the planetary drive serves as input and the flexible wheel in the harmonic serves as output, thereby improving the transmission ratio and increasing the transmitted torque. However, the flexible wheel cannot withstand excessive torque due to its thin-walled characteristics. Publication No. CN117605807B discloses a power-dividing harmonic reducer, which is composed of a planetary drive and a harmonic drive connected in parallel, wherein the planet carrier of the planetary drive serves as input, and power diversion is achieved through the common output of the sun gear and the flexible wheel, thereby increasing the transmission ratio and reducing the torque transmitted by the flexible wheel. However, the cam in the harmonic reducer is usually small in size, and embedding the planetary drive in the cam will cause problems of difficulty in planetary-level processing and assembly.

[0004] In order to solve the above problems, the present invention provides a planetary harmonic reducer with power splitting. By replacing the sun gear in the planetary transmission with a harmonic differential gear train, internal and external teeth are set in the rigid wheel, and the power is split to the harmonic differential gear train and the planetary gear train through the internal and external teeth of the rigid wheel. The cam in the harmonic reducer is used as the input, and the flexible wheel and the planet carrier jointly output to realize power splitting, thereby increasing the transmission ratio of the reducer and reducing the bearing torque of the flexible wheel, extending the service life of the flexible wheel, and avoiding the problem of difficult processing and assembly. Summary of the invention

[0005] The purpose of the present invention is to provide a power split planetary harmonic reducer to solve the above-mentioned problems.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a power split planetary harmonic reducer, comprising an input shaft, the input shaft is fixedly connected to a wave generator, an outer cover of the wave generator is provided with a flexible wheel, an outer gear ring end of the flexible wheel is meshed with an inner gear ring of a steel wheel, the outer gear ring of the steel wheel is meshed with a planetary wheel, the planetary wheel is arranged on a planetary carrier, and a rigid inner gear ring is meshed on the outer periphery of the planetary wheel; an output housing is rotatably provided at the shaft end of the planetary carrier; a barrel end of the flexible wheel is fixedly connected to an output shaft, the output shaft is located at the center of the output housing, and the output shaft and the output housing are an integrally formed structure.

[0008] Furthermore, the wave generator includes a cam, and a flexible bearing is provided between the cam and the flexible wheel.

[0009] Furthermore, the output housing is provided with a plurality of through holes which match with the shaft ends of the planet carrier.

[0010] Furthermore, a tapered roller bearing is provided between the output housing and the shaft end of the planet carrier.

[0011] Furthermore, the shaft end sleeve of the planet carrier is provided with a spline that meshes with the planetary gear.

[0012] Furthermore, the flexible wheel is a flexible thin-walled cylindrical structure, including an outer gear ring of the flexible wheel that is flush with the end surface of the inner gear ring of the steel wheel.

[0013] Furthermore, the outer gear ring of the flexible wheel and the inner gear ring of the steel wheel are double circular arc gears, and the outer gear ring of the steel wheel, the planetary gear and the rigid inner gear ring of the steel wheel are involute gears.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are:

[0015] In the power split planetary harmonic reducer of the invention, the wave generator, the flexible wheel, and the inner gear ring of the rigid wheel constitute a harmonic differential gear system. The wave generator is connected to the input shaft as the input. The flexible wheel and the rigid wheel are not fixed. The outer teeth of the flexible wheel mesh with the inner teeth of the rigid wheel to drive the rigid wheel to move. At the same time, the flexible wheel cylinder is connected to the output end through bolts as the output; the outer gear ring of the rigid wheel serves as the sun gear, meshes with the planetary gear and makes it move. The movement of the planetary gear drives the movement of the planetary carrier. The inner gear ring is fixed, and the inner gear ring is connected to the output end as the output. In short, the present invention adopts a combined structure of planetary transmission and harmonic transmission. On the basis of not changing the size of the planetary transmission structure, the power is transmitted to the output end cover through the planetary carrier and the flexible wheel cylinder, which increases the motion transmission torque and realizes a high reduction ratio. At the same time, the harmonic transmission and the planetary transmission are used to output the power together, which shares the torque carried by the flexible wheel, increases the transmission ratio, and improves the service life of the flexible wheel. In addition, the power split can be realized through the harmonic differential gear system. The way of outputting the flexible wheel and the planetary carrier together increases the transmitted torque, and the processing is convenient, the assembly is simple, and the overall structure is compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 This is an exploded view of the power split planetary harmonic reducer of the present invention;

[0018] Figure 2 This is the transmission principle diagram of the power split planetary harmonic reducer of the present invention;

[0019] Figure 3 It is a cross-sectional view of the power split planetary harmonic reducer of the present invention;

[0020] Figure 4 It is a structural schematic diagram of the planetary gear and the planetary carrier;

[0021] Figure 5 It is a schematic diagram of the rigid wheel structure;

[0022] Figure 6 It is a schematic diagram of the flexible wheel structure;

[0023] Explanation of the reference numerals: 1. rigid inner gear ring; 2. output housing; 3. output shaft; 4. flexible wheel; 5. rigid wheel outer gear ring; 6. tapered roller bearing; 7. planetary gear; 8. planetary carrier; 9. rigid wheel inner gear ring; 10. flexible bearing; 11. cam; 12; input shaft; 13. wave generator. DETAILED DESCRIPTION

[0024] like Figure 1-6 As shown, a power split planetary harmonic reducer includes an input shaft 12, the input shaft 12 is fixedly connected to a wave generator 13, the wave generator 13 includes a cam 11, and a flexible bearing 10 is installed between the cam 11 and the flexible wheel 4. The input shaft 12 is connected to the cam 11 through a flat key to transmit power.

[0025] The outer side of the wave generator 13 is equipped with a flexible wheel 4, and the outer gear ring end of the flexible wheel 4 is meshed with the inner gear ring 9 of the steel wheel, and the outer gear ring 5 of the steel wheel is meshed with the planetary wheel 7. The flexible wheel 4 is a flexible thin-walled cylindrical structure, including the outer gear ring of the flexible wheel 4 and the end surface of the inner gear ring 9 of the steel wheel. The wave generator 13 is stretched to force the flexible wheel 4 to undergo elastic deformation, and the cam 11 drives the flexible wheel 4 to move. The outer gear ring on the flexible wheel 4 and the inner gear ring 9 of the steel wheel are meshed with each other, and a cycle of meshing, meshing, and meshing out occurs. At the same time, the barrel end of the flexible wheel 4 is fixedly connected to the output shaft 3 to provide output power. The planetary wheel 7 is installed on the planetary carrier 8, and the outer periphery of the planetary wheel 7 is meshed with a rigid inner gear ring 1, which is fixed. The output housing 2 is rotatably installed on the shaft end of the planetary carrier 8, and the output housing 2 is driven to rotate when the planetary carrier 8 rotates. The output shaft 3 is located at the center of the output housing 2 , and the output shaft 3 and the output housing 2 are an integrally formed structure.

[0026] Specifically, when the inner gear ring 9 of the steel wheel rotates, the steel wheel also rotates. Since the rotation speed of the steel wheel is lower than the rotation speed of the flexible wheel 4, the rotation of the steel wheel does not hinder the meshing, engagement and disengagement operation process of the flexible wheel 4. When the steel wheel rotates, the outer gear ring 5 of the steel wheel serves as the sun gear of the planetary mechanism, which drives the planetary wheel 7 meshing with it to rotate, and the planetary wheel 7 drives the output housing 2 to rotate, so that the output end of the reducer in this embodiment is changed from a single output shaft 3 to an output shaft 3 and an output housing 2, which shares the torque carried by the flexible wheel 4, increases the transmission ratio, and improves the service life of the flexible wheel 4.

[0027] Design Principle of Power Split Planetary Harmonic Reducer

[0028] Assume that the input speed of the wave generator is n1, the output speed of the flexible wheel and the planet carrier is n2, and the speed of the rigid wheel is nc.

[0029] 1) From the power transmission, it can be known that the input speed n1 of the wave generator is transmitted to the flexible wheel through harmonic deformation as n2, the flexible wheel meshes with the inner gear ring of the rigid wheel to transmit the speed to the rigid wheel as nc, the outer gear ring of the rigid wheel meshes with the planetary gear, the planetary gear drives the planetary carrier to rotate, and transmits the power to the planetary carrier as n2;

[0030] 2) Apply a speed of -nc to the entire planetary harmonic reducer. At this time, the rigid wheel, planet carrier, and inner ring gear form a planetary gear train. The planetary gear train transmission ratio calculation formula shows that:

[0031]

[0032] Solution Right now After the gear train conversion, the flexspline speed becomes 0, and it can be considered that the flexspline is fixed. The wave generator, flexspline, and rigid wheel inner gear ring constitute a harmonic gear train. The formula for calculating the transmission ratio of the harmonic gear train shows that:

[0033]

[0034] By expressing nc with n2, we can get the relationship between n1 and n2, that is, the transmission ratio of the whole machine can be obtained:

[0035]

[0036] The output housing 2 is provided with a plurality of through holes matched with the shaft ends of the planet carrier 8, and a tapered roller bearing 6 is installed between the output housing 2 and the shaft ends of the planet carrier 8, that is, a tapered roller bearing 6 is provided between the through holes and the shaft ends.

[0037] The shaft end of the planet carrier 8 is sleeved with a spline that meshes with the planet gear 7 .

[0038] The outer gear ring of the flexible wheel 4 and the inner gear ring 9 of the steel wheel are double circular arc gears, and the outer gear ring 5 of the steel wheel, the planetary gear 7 and the rigid inner gear ring 1 are involute gears.

[0039] The action process of the present invention is as follows:

[0040] First, the input shaft 12 drives the wave generator 13 to rotate, and the wave generator 13 is stretched to force the flexible wheel 4 to undergo elastic deformation, and the cam 11 drives the flexible wheel 4 to move, and the outer gear ring on the flexible wheel 4 and the inner gear ring 9 of the steel wheel are meshed with each other, and a cycle of meshing in, meshing in, and meshing out occurs. At the same time, the barrel end of the flexible wheel 4 is fixedly connected to the output shaft 3 to provide output power;

[0041] Afterwards, the steel wheel rotates under the action of the flexible wheel 4, and the outer gear ring 5 of the steel wheel serves as the sun wheel of the planetary mechanism, which drives the planetary wheel 7 meshing with it to rotate, and the planetary wheel 7 drives the planetary carrier 8 to rotate, and the planetary carrier 8 drives the output housing 2 to rotate to provide output power;

[0042] Finally, the output shaft 3 and the output housing 2 rotate under the action of the output power, and jointly drive the part to be rotated to rotate.

[0043] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A power split planetary harmonic reducer, characterized in that: The invention comprises an input shaft (12), wherein the input shaft (12) is fixedly connected to a wave generator (13), an outer cover of the wave generator (13) is provided with a flexible wheel (4), an outer gear ring end of the flexible wheel (4) is meshed with an inner gear ring (9) of a steel wheel, an outer gear ring (5) of the steel wheel is meshed with a planetary wheel (7), the planetary wheel (7) is arranged on a planetary carrier (8), and a rigid inner gear ring (1) is meshed around the outer periphery of the planetary wheel (7); an output housing (2) is rotatably provided at the shaft end of the planetary carrier (8); a barrel end of the flexible wheel (4) is fixedly connected to an output shaft (3), the output shaft (3) is located at the center of the output housing (2), and the output shaft (3) and the output housing (2) are an integrally formed structure.

2. The power split planetary harmonic reducer according to claim 1, characterized in that: The wave generator (13) comprises a cam (11), and a flexible bearing (10) is arranged between the cam (11) and the flexible wheel (4).

3. The power split planetary harmonic reducer according to claim 1, characterized in that: The output housing (2) is provided with a plurality of through holes which match the shaft ends of the planet carrier (8).

4. The power split planetary harmonic reducer according to claim 1, characterized in that: A tapered roller bearing (6) is arranged between the output housing (2) and the shaft end of the planet carrier (8).

5. The power split planetary harmonic reducer according to claim 1, characterized in that: The shaft end sleeve of the planet carrier (8) is provided with a spline that meshes with the planet gear (7).

6. The power split planetary harmonic reducer according to claim 1, characterized in that: The flexible wheel (4) is a flexible thin-walled cylindrical structure, including an outer gear ring of the flexible wheel (4) and an end surface of an inner gear ring (9) of the steel wheel flush with each other.

7. The power split planetary harmonic reducer according to claim 1, characterized in that: The outer gear ring of the flexible wheel (4) and the inner gear ring (9) of the steel wheel are double circular arc gears, and the outer gear ring (5), the planetary wheel (7) and the rigid inner gear ring (1) of the steel wheel are involute gears.

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