A flexible gear and a harmonic reducer having the same.

Abstract

This invention provides a flexible gear and a harmonic reducer having the same. The flexible gear has a cylindrical structure and includes a transmission part. Along the axial direction of the transmission part, the inner peripheral wall of the transmission part has a segmented structure, and the segmented structure includes at least a first shaft segment, a second shaft segment, and a third shaft segment connected in sequence. The average wall thickness of the transmission part at the second shaft segment is not only greater than the average wall thickness of the transmission part at the first shaft segment but also greater than the average wall thickness of the transmission part at the third shaft segment. The outer peripheral wall of the transmission part has external teeth. The first and third shaft segments have unequal inner diameter structures, while the second shaft segment has a constant inner diameter structure. Along the direction from the first shaft segment to the third shaft segment, the inner diameter of the first shaft segment gradually decreases, and the inner diameter of the third shaft segment gradually increases, making it easier for the outer ring of the flexible bearing to be pressed into the inner side of the second shaft segment, and the outer ring of the flexible bearing is interference-fitted with the second shaft segment. This increases the wall thickness of the transmission part at the external teeth, improves the load-bearing strength of the external teeth, and solves the problem of easy cracking of the side wall of the transmission part at the external teeth.

Description

Technical Field

[0001] This invention belongs to the field of speed reducer technology, and particularly relates to a flexible gear and a harmonic speed reducer having the same. Background Technology

[0002] Harmonic reducers mainly consist of a rigid wheel, a flexible wheel, and a wave generator. They have advantages such as high transmission accuracy, large speed ratio, small size, simple structure, and wide application range. The working process of a harmonic reducer involves the rotation of a hollow shaft, with a flexible bearing causing elastic deformation of the flexible wheel. The external teeth of the flexible wheel mesh with the internal teeth of the rigid wheel, thereby transmitting motion and power. The main problem in the development of the harmonic reducer industry is its lifespan. Failures can be caused by fractures at the root of the external teeth of the flexible wheel, tears at the flange, or the detachment of the wave generator.

[0003] The flexible gear is the core component of the harmonic generator, and the wall thickness of the flexible gear at the external tooth is a critical dimension. In existing harmonic reducers, the wall thickness of the flexible gear at the external tooth is too small, resulting in low load-bearing strength of the flexible gear. This leads to easy breakage of the external tooth and easy cracking of the side wall of the flexible gear at the external tooth, shortening the life of the flexible gear and causing functional failure. Summary of the Invention

[0004] In view of this, the present invention provides a flexible gear and a harmonic reducer having the same, to solve the problems in existing harmonic reducers such as the flexible gear having too small a wall thickness at the external teeth, which leads to easy breakage of the external teeth, easy cracking of the flexible gear sidewall at the external teeth, and short lifespan of the flexible gear.

[0005] This invention provides a flexible wheel for a harmonic reducer. The flexible wheel has a cylindrical structure and includes a transmission part. Along the axial direction of the transmission part, the inner peripheral wall of the transmission part has a segmented structure, and the segmented structure includes at least a first shaft segment, a second shaft segment, and a third shaft segment connected in sequence. The average wall thickness of the transmission part at the second shaft segment is not only greater than the average wall thickness of the transmission part at the first shaft segment but also greater than the average wall thickness of the transmission part at the third shaft segment.

[0006] The outer peripheral wall of the transmission part is formed with external teeth.

[0007] Alternatively, the second shaft segment has a constant inner diameter structure, while the first and third shaft segments have unequal inner diameter structures.

[0008] Further optionally, along the direction from the first shaft segment to the third shaft segment, the inner diameter of the first shaft segment gradually decreases, and the inner diameter of the third shaft segment gradually increases.

[0009] Optionally, a flexible bearing is provided on the inner side of the second shaft segment, satisfying s1 = 0.5*(D c -d1), d1=|k1*H+D r+k2|, where 0 < H < H1, 0.01745 ≤ k1 ≤ 0.17633, -0.2 ≤ k2 ≤ 0;

[0010] where s1 is the wall thickness of the transmission part at the first shaft section, D c is the outer diameter of the transmission part, d1 is the inner diameter of the first shaft section, H1 is the axial length of the first shaft section, H is the axial length between any cross-section of the transmission part and the preset end face, D r is the diameter of the outer ring of the flexible bearing, k1 and k2 are coefficients; the preset end face is the end face of the transmission part close to the first shaft section;

[0011] Preferably, k1 = -0.087798 and k2 = -0.114.

[0012] Further optionally, it satisfies s2 = 0.5*(D c - d2), d2 = |k3*D r |, where H1 < H < H2, -0.9985 ≤ k3 ≤ -0.999;

[0013] where s2 is the wall thickness of the transmission part at the second shaft section, d2 is the inner diameter of the second shaft section, H2 is the axial length of the second shaft section, and k3 is a coefficient;

[0014] Preferably, k3 = -0.9995.

[0015] Further optionally, it satisfies s3 = 0.5*(D c - d3), d3 = |k4*H + D r + k5|, where H2 < H < H3, 0.01745 ≤ k4 ≤ 0.0874, 0.38 ≤ k5 ≤ 0.49;

[0016] where s3 is the wall thickness of the transmission part at the third shaft section, d3 is the inner diameter of the third shaft section, H3 is the axial length of the third shaft section, and k4 and k5 are coefficients;

[0017] Preferably, k4 = 0.034954 and k5 = 0.285.

[0018] The present invention also provides a harmonic reducer, which includes the flexspline and the wave generator described in any one of the above; the wave generator includes a hollow shaft and a flexible bearing, and the hollow shaft is formed with a cam; the hollow shaft is arranged inside the flexspline, and the cam is connected to the transmission part through the flexible bearing.

[0019] Further optionally, a first conical structure is formed on the outer peripheral wall of the cam, and the taper of the first conical structure is ε1, satisfying 2.5° ≤ ε1 ≤ 3.5°;

[0020] The inner ring of the flexible bearing has a second conical structure formed on its inner peripheral wall. The taper of the second conical structure is ε2, which satisfies 2.5°≤ε2≤3.5°.

[0021] Further optionally, the first tapered structure comprises two, the two first tapered structures being symmetrical about the central cross-section of the cam; the second tapered structure comprises two, the two second tapered structures being symmetrical about the central cross-section of the inner ring of the flexible bearing;

[0022] The two first conical structures are connected at their smallest outer diameter ends, and the two second conical structures are connected at their largest inner diameter ends; or the two first conical structures are connected at their largest outer diameter ends, and the two second conical structures are connected at their smallest inner diameter ends.

[0023] Further optionally, the flexible wheel also includes a transition section and a connecting section, and the transmission section, the transition section and the connecting section are arranged and connected in sequence; the harmonic reducer also includes a rigid wheel, a rigid wheel flange and a rigid bearing;

[0024] The rigid wheel has internal teeth and is sleeved on the outside of the flexible wheel, with the internal teeth meshing with the external teeth; the rigid wheel flange is disposed at one end of the rigid wheel and connected to the rigid wheel, and the rigid wheel flange is located on the side of the transmission part away from the transition part;

[0025] The rigid bearing is disposed at the other end of the rigid wheel away from the rigid wheel flange and is connected to the rigid wheel. The rigid bearing is sleeved on the outside of the transition part, and the end of the rigid bearing away from the rigid wheel is connected to the connecting part.

[0026] Compared with the prior art, the main advantages of the present invention are as follows:

[0027] (1) The structure of the transmission part was optimized by designing the inner peripheral wall of the transmission part as a segmented structure, which increased the wall thickness of the transmission part at the external teeth, ensuring that the wall thickness between the tooth root of the external teeth and the second shaft segment was maximized, thereby improving the load-bearing strength of the flexible wheel and extending its lifespan. This solved the problems of the external teeth being prone to breakage due to the insufficient wall thickness of the transmission part at the external teeth, the sidewall of the transmission part being prone to cracking, and the flexible wheel having a short lifespan.

[0028] (2) Both the first and third shaft sections have unequal inner diameter structures, while the second shaft section has an equal inner diameter structure. Along the direction from the first shaft section to the third shaft section, the inner diameter of the first shaft section gradually decreases, while the inner diameter of the third shaft section gradually increases, making it easier for the outer ring of the flexible bearing to be pressed into the inner side of the second shaft section, and the outer ring of the flexible bearing is interference-fitted with the second shaft section.

[0029] The first, second, and third shaft segments were calculated using corresponding formulas, which optimized the wall thickness of the flexible wheel, increased the wall thickness of the transmission part at the external teeth, and improved the load-bearing strength of the external teeth.

[0030] (3) The hollow shaft forms a cam, and the outer peripheral wall of the cam forms a first conical structure. The inner peripheral wall of the inner ring of the flexible bearing forms a second conical structure. The first conical structure and the second conical structure cooperate to achieve an interference fit between the inner ring of the flexible bearing and the cam. A certain preload and resistance are formed between the two, which improves the reliability of the connection between the two and avoids the flexible bearing from being subjected to unbalanced force during use, causing the flexible bearing to slide up and down along the hollow shaft and fall off. This makes the wave generator composed of the hollow shaft and the flexible bearing more stable, improves the transmission efficiency between the cam and the flexible bearing, effectively improves the input torque of the harmonic reducer, and makes the harmonic reducer have a higher load-bearing capacity. Attached Figure Description

[0031] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0032] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0033] Figure 1a , Figure 1b , Figure 1c and Figure 1d This is a schematic diagram of the structure of a flexible wheel embodiment provided by the present invention;

[0034] Figure 2a for Figure 1b Enlarged view of point A in the middle;

[0035] Figure 2b for Figure 1c Enlarged view at point B in the middle;

[0036] Figure 3a , Figure 3b and Figure 3c A schematic diagram of the structure of an embodiment of the flexible bearing provided by the present invention;

[0037] Figure 4a , Figure 4b , Figure 4c and Figure 4d A schematic diagram of the hollow shaft embodiment provided by the present invention;

[0038] Figure 5 This is a schematic diagram of the assembly structure of the flexible wheel and flexible bearing embodiment provided by the present invention;

[0039] Figure 6a , Figure 6b , Figure 6c and Figure 6d This is a schematic diagram of the assembly structure of the hollow shaft and flexible bearing embodiment provided by the present invention;

[0040] Figure 7a and Figure 7b This is a schematic diagram of the assembly structure of an embodiment of the harmonic reducer provided by the present invention;

[0041] Figure 7c This is an exploded structural diagram of an embodiment of the harmonic reducer provided by the present invention;

[0042] In the picture:

[0043] 1-Flexible gear; 11-Transmission part; 111-First shaft section; 112-Second shaft section; 113-Third shaft section; 114-External gear; 12-Transition part; 13-Connecting part; 14-Preset end face;

[0044] 21-Hollow shaft; 211-Cam; 22-Flexible bearing;

[0045] 3-Harmonic reducer; 31-Rigid wheel flange; 32-Rigid wheel; 33-Rigid bearing; 34-Angular contact ball bearing; 35-Skeleton oil seal; 36-Flexible wheel flange. Detailed Implementation

[0046] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0048] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0049] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0050] In existing harmonic reducers, the wall thickness of the flexure at the external teeth is too small, resulting in low load-bearing strength of the flexure. This leads to easy breakage of the external teeth and easy cracking of the sidewall of the flexure at the external teeth, shortening the life of the flexure and causing functional failure.

[0051] This invention creatively provides a flexible wheel for a harmonic reducer. The flexible wheel has a cylindrical structure and includes a transmission part. Along the axial direction of the transmission part, the inner peripheral wall of the transmission part has a segmented structure, and the segmented structure includes at least a first shaft segment, a second shaft segment, and a third shaft segment connected in sequence. The average wall thickness of the transmission part at the second shaft segment is not only greater than the average wall thickness of the transmission part at the first shaft segment but also greater than the average wall thickness of the transmission part at the third shaft segment. The outer peripheral wall of the transmission part is formed with external teeth.

[0052] The structure of the transmission part was optimized by designing the inner peripheral wall of the transmission part as a segmented structure, increasing the wall thickness of the transmission part at the external teeth, ensuring the maximum wall thickness between the tooth root of the external teeth and the second shaft segment, improving the load-bearing strength of the flexible wheel, and increasing the service life of the flexible wheel; solving the problems of the external teeth being prone to breakage due to the insufficient wall thickness of the transmission part at the external teeth, the side walls of the transmission part being prone to cracking at the external teeth, and the short service life of the flexible wheel.

[0053] Example 1

[0054] <Flexible Wheel>

[0055] like Figure 1a , Figure 1b , Figure 1c and Figure 1dAs shown, this embodiment provides a flexible wheel 1 for a harmonic reducer 3. The flexible wheel 1 has a cylindrical structure and includes a transmission part 11, a transition part 12 and a connecting part 13 connected in sequence. The transmission part 11, the transition part 12 and the connecting part 13 are coaxially arranged. The transmission part 11 is used to transmit motion and power, the transition part 12 is used to connect the transmission part 11 and the connecting part 13, and the connecting part 13 is used to connect other components.

[0056] Along the axial direction of the transmission part 11, the inner peripheral wall of the transmission part 11 has a segmented structure, and the segmented structure includes a first shaft segment 111, a second shaft segment 112, and a third shaft segment 113 connected in sequence. The first shaft segment 111, the second shaft segment 112, and the third shaft segment 113 are coaxially arranged. The average wall thickness of the transmission part 11 at the second shaft segment 112 is not only greater than the average wall thickness of the transmission part 11 at the first shaft segment 111, but also greater than the average wall thickness of the transmission part 11 at the third shaft segment 113. The end of the transmission part 11 near the first shaft segment 111 has an open structure.

[0057] External teeth 114 are formed on the outer periphery of the transmission part 11; such as Figure 5 As shown, a flexible bearing 22 is provided on the inner side of the second shaft segment 112. Specifically, the inner circumference of the second shaft segment 112 is interference-fitted with the outer ring of the flexible bearing 22.

[0058] In summary, the structure of the transmission part 11 has been optimized, and the wall thickness of the transmission part at the external teeth has been significantly increased, so that the tooth root of the external teeth 114 is effectively connected to the outer peripheral wall of the transmission part, thereby improving the load-bearing capacity of the external teeth 114, further improving the load-bearing strength of the flexible wheel 1, extending the service life of the flexible wheel 1, avoiding the problem that the external teeth 114 are prone to breakage due to the insufficient wall thickness of the transmission part at the external teeth and the second shaft part is prone to cracking, thus solving the problems of low load-bearing capacity and short service life of the flexible wheel 1.

[0059] Furthermore, the second shaft segment 112 has a constant inner diameter structure, while the first shaft segment 111 and the third shaft segment 113 both have unequal inner diameter structures;

[0060] Along the direction from the first shaft segment 111 to the third shaft segment 113, the inner diameter of the first shaft segment 111 gradually decreases, and the inner diameter of the third shaft segment 113 gradually increases; this makes it easier for the outer ring of the flexible bearing 22 to be pressed into the inner side of the second shaft segment 112, making the connection between the outer ring of the flexible bearing 22 and the second shaft segment 112 more reliable, and improving the transmission efficiency between the flexible bearing 22 and the second shaft segment 112.

[0061] like Figure 2a and Figure 2b As shown, to address the problem that the unreasonable wall thickness design of the transmission part 11 at the external tooth 114 leads to easy breakage of the external tooth 114 and easy failure of the flexible wheel 1, this embodiment proposes that a flexible bearing 22 be provided on the inner circumference side of the second shaft section 112, and the first shaft section 111 satisfies s1=0.5*(D c-d1), where d1 = |k1*H + D r + k2|, 0 < H < H1, 0.01745 ≤ k1 ≤ 0.17633, -0.2 ≤ k2 ≤ 0;

[0062] Where, s1 is the wall thickness of the transmission part 11 at the first shaft segment 111, D c is the outer diameter of the transmission part 11, d1 is the inner diameter of the first shaft segment 111, H1 is the axial length of the first shaft segment 111, H is the axial length between any cross-section of the transmission part 11 and the preset end face 14, D r is the diameter of the outer ring of the flexible bearing 22, k1 and k2 are coefficients; the preset end face 14 is the end face of the transmission part 11 close to the first shaft segment 111;

[0063] Preferably, k1 = -0.087798, k2 = -0.114.

[0064] Further, the second shaft segment 112 satisfies s2 = 0.5*(D c - d2), where d2 = |k3*D r |, H1 < H < H2, -0.9985 ≤ k3 ≤ -0.999;

[0065] Where, s2 is the wall thickness of the transmission part 11 at the second shaft segment 112, d2 is the inner diameter of the second shaft segment 112, H2 is the axial length of the second shaft segment 112, k3 is a coefficient;

[0066] Preferably, k3 = -0.9995.

[0067] In addition, the third shaft segment 113 satisfies s3 = 0.5*(D c - d3), where d3 = |k4*H + D r + k5|, H2 < H < H3, 0.01745 ≤ k4 ≤ 0.0874, 0.38 ≤ k5 ≤ 0.49;

[0068] Where, s3 is the wall thickness of the transmission part 11 at the third shaft segment 113, d3 is the inner diameter of the third shaft segment 113, H3 is the axial length of the third shaft segment 113, k4 and k5 are coefficients;

[0069] Preferably, k4 = 0.034954, k5 = 0.285.

[0070] The first shaft segment 111, the second shaft segment 112 and the third shaft segment 113 are calculated using the corresponding formulas respectively, which optimizes the wall thickness of the flexspline 1, increases the wall thickness of the transmission part 11 at the external teeth 114, and improves the bearing strength of the external teeth 114.

[0071] Specifically, in this embodiment, the diameters and heights of each shaft segment of the transmission part 11 and the diameter of the outer ring of the flexible bearing 22 are defined. Taking the preset end face 14 as the reference, d refers to the inner diameter of the transmission part 11, H is the axial length between any cross-section of the transmission part 11 and the preset end face 14, and D r is the diameter of the outer ring of the flexible bearing 22; H1 is the axial length of the first shaft segment 111. Along the direction from the first shaft segment 111 to the second shaft segment 112, the inner diameter of the first shaft segment 111 gradually decreases and it is a conical structure. The taper of the first shaft segment 111 is α. The function of this design is to facilitate the introduction of the flexible bearing 22 into the inner side of the second shaft segment 112. The inner diameter d1 of the first shaft segment 111 = |-0.087798H + D r - 0.114| (0 < H < H1);

[0072] The second shaft segment 112 is a straight cylinder. H2 is the axial length of the second shaft segment 112. The second shaft segment 112 keeps the distance between the tooth root of the external tooth 114 and the second shaft segment 112 the largest. The outer ring of the flexible bearing 22 is in interference fit with the second shaft segment 112, so that the flexspline 1 meshes with the rigid ring 32. The inner diameter d2 of the second shaft segment 112 = |-0.9995D r | (H1 < H < H2);

[0073] H3 is the axial length of the third shaft segment 113. Along the direction from the second shaft segment 112 to the third shaft segment 113, the inner diameter of the third shaft segment 113 gradually increases and it is a conical structure. The taper of the third shaft segment 113 is β. The straight line of the third shaft segment 113 can increase the wall thickness value K of the second shaft segment 112. The inner diameter d3 of the third shaft segment 112 = |0.034954H + D r + 0.285| (H2 < H < H3); The axial lengths of the first shaft segment 111, the second shaft segment 112, and the third shaft segment 113 satisfy: H3 > H2 > H1.

[0074] <Wave generator>

[0075] As Figure 3a and Figure 4a shown, this embodiment provides a wave generator. The wave generator includes a hollow shaft 21 and a flexible bearing 22. The hollow shaft 21 is formed with a cam 211. The cam 211 is an annular structure and the cam 211 is coaxially arranged with the hollow shaft 21; The hollow shaft 21 is arranged inside the flexspline 1, and the cam 211 is connected to the transmission part 11 through the flexible bearing 22; Specifically, the outer ring of the flexible bearing 22 is in interference fit with the inner peripheral wall of the second shaft part, and the inner ring of the flexible bearing 22 is in interference fit with the outer peripheral side of the cam 211; The outer contour of the cam 211 is an ellipse or a cosine structure.

[0076] As Figure 3b 、 Figure 3c 、 Figure 4b , Figure 4c and Figure 4d As shown, in response to the problem that the inner ring of the flexible bearing 22 is easily detached due to the unreliable connection between the cam 211 and the inner ring of the flexible bearing 22, this embodiment proposes that the outer peripheral wall of the cam 211 is formed with a first conical structure, the taper of the first conical structure being ε1, which satisfies 2.5°≤ε1≤3.5°.

[0077] The inner ring of the flexible bearing 22 has a second conical structure formed on its inner peripheral wall. The taper of the second conical structure is ε2, which satisfies 2.5°≤ε2≤3.5°.

[0078] In summary, the first and second conical structures work together to achieve an interference fit between the inner ring of the flexible bearing 22 and the cam 211. This creates a certain preload and resistance between the two, improving the reliability of their connection. It also prevents the flexible bearing 22 from slipping and falling off along the hollow shaft 21 due to unbalanced forces during use. This makes the wave generator composed of the hollow shaft 21 and the flexible bearing 22 more stable, improves the transmission efficiency between the cam 211 and the flexible bearing 22, effectively increases the input torque of the harmonic reducer 3, and gives the harmonic reducer 3 a higher load-bearing capacity.

[0079] Furthermore, the first tapered structure comprises two, and the two first tapered structures are symmetrical about the central cross-section of the cam 211; the second tapered structure comprises two, and the two second tapered structures are symmetrical about the central cross-section of the inner ring of the flexible bearing 22;

[0080] like Figure 6a , Figure 6b , Figure 6c and Figure 6d As shown, the two first conical structures are connected at their smallest outer diameter ends, correspondingly, as... Figure 3b As shown, the two second conical structures are connected at their maximum inner diameter ends to ensure that the first and second conical structures are compatible and to improve the reliability of the connection between the cam 211 and the inner ring of the flexible bearing 22. Specifically, the minimum inner diameter of the two second conical structures is r1, and the maximum inner diameter of the two second conical structures is r2.

[0081] Harmonic reducer

[0082] like Figure 7a , Figure 7b and Figure 7c As shown, this embodiment also provides a harmonic generator, including a rigid wheel 32, a rigid wheel flange 31, a rigid bearing 33, a flexible wheel flange 36, the aforementioned flexible wheel 1, and a wave generator;

[0083] The rigid wheel 32 has internal teeth and is sleeved on the outside of the flexible wheel 1 and coaxially arranged with the flexible wheel 1. The internal teeth mesh with the external teeth 114, which can realize the transmission of motion and power between the flexible wheel 1 and the rigid wheel 32. The rigid wheel flange 31 is arranged at one end of the rigid wheel 32 and is fixedly connected to the rigid wheel 32 by bolts. The rigid wheel flange 31 is located on the side of the transmission part 11 away from the transition part 12. The rigid wheel flange 31 is connected to the actuator and can drive the actuator to move. The actuator can be a specific actuator in bionic machinery, lifting machinery, petrochemical machinery, textile machinery, agricultural machinery, and medical devices, for example, the actuator can be a robotic arm. The inner peripheral wall of the rigid wheel flange 31 forms a first through hole and a second through hole. The hollow shaft 21 passes through the first through hole and the second through hole. An angular contact ball bearing 34 is arranged between the hollow shaft 21 and the first through hole, and a skeleton oil seal 35 is arranged between the hollow shaft 21 and the first through hole.

[0084] A rigid bearing 33 is disposed at the other end of the rigid wheel 32 away from the rigid wheel flange 31 and is connected to the rigid wheel 32. The rigid bearing 33 is sleeved on the outside of the transition part 12, and the end of the rigid bearing 33 away from the rigid wheel 32 is connected to the connecting part 13 and the flexible wheel flange 36. Specifically, the connecting part 13 forms an annular mounting groove. The end of the inner ring of the rigid bearing 33 near the rigid wheel 32 is fixedly connected to the rigid wheel 32. The end of the inner ring of the rigid bearing 33 away from the rigid wheel 32 is connected to the connecting part 13. The end of the outer ring of the rigid bearing 33 away from the rigid wheel 32 is connected to the flexible wheel flange 36.

[0085] The cam 211 is interference-fitted with the inner ring of the flexible bearing 22, and the outer ring of the flexible bearing 22 is interference-fitted with the inner circumferential wall of the second shaft section 112. The outer teeth 114 of the flexible wheel 1 mesh with the inner teeth of the rigid wheel 32. Along the axial direction of the rigid wheel 32, the rigid wheel flange 31, the rigid wheel 32, the rigid bearing 33, and the flexible wheel flange 36 are arranged and connected in sequence. Increasing the wall thickness of the transmission part 11 at the outer teeth improves the load-bearing strength of the flexible wheel 1, expands the application range of the flexible wheel 1, and makes the same flexible wheel 1 applicable to different rigid wheels 32, thereby improving the service life of the harmonic reducer 3.

[0086] The hollow shaft 21 rotates at high speed, and the flexible bearing 22 drives the flexible wheel 1 to undergo continuous periodic flexible deformation. A portion of the external teeth 114 of the flexible wheel 1 meshes with a portion of the internal teeth of the rigid wheel 32. The number of teeth on the external teeth 114 of the flexible wheel 1 is two fewer than the number of teeth on the internal teeth of the rigid wheel 32. The two mesh with each other to form a small tooth difference transmission. The rigid wheel 32 rotates, and then the rigid wheel flange 31 drives the actuator to move.

[0087] Example 2

[0088] Unlike Embodiment 1, the two first conical structures are connected at their largest outer diameter ends, and the two second conical structures are connected at their smallest inner diameter ends, ensuring that the first and second conical structures are compatible and improving the reliability of the connection between the cam 211 and the inner ring of the flexible bearing 22.

[0089] Exemplary embodiments of this disclosure have been specifically shown and described above. It should be understood that this disclosure is not limited to the detailed structures, arrangements, or implementations described herein; rather, this disclosure is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A harmonic reducer, characterized in that, The device includes a flexible wheel (1) and a wave generator; the flexible wheel (1) has a cylindrical structure and includes a transmission part (11); along the axial direction of the transmission part (11), the inner peripheral wall of the transmission part (11) has a segmented structure, and the segmented structure includes at least a first shaft segment (111), a second shaft segment (112), and a third shaft segment (113) connected in sequence; the average wall thickness of the transmission part (11) at the second shaft segment (112) is not only greater than the average wall thickness of the transmission part (11) at the first shaft segment (111) but also greater than the average wall thickness of the transmission part (11) at the third shaft segment (113); the outer peripheral wall of the transmission part (11) is formed with external teeth (114); The wave generator includes a hollow shaft (21) and a flexible bearing (22). The hollow shaft (21) has a cam (211). The hollow shaft (21) is located inside the flexible wheel (1), and the cam (211) is connected to the transmission part (11) through the flexible bearing (22). The outer peripheral wall of the cam (211) has a first conical structure, and the inner peripheral wall of the inner ring of the flexible bearing (22) has a second conical structure; the first conical structure and the second conical structure cooperate to achieve an interference fit between the inner ring of the flexible bearing (22) and the cam (211).

2. The harmonic reducer according to claim 1, characterized in that, The second shaft segment (112) has a constant inner diameter structure, while the first shaft segment (111) and the third shaft segment (113) have unequal inner diameter structures.

3. The harmonic reducer according to claim 2, characterized in that, Along the direction from the first shaft segment (111) to the third shaft segment (113), the inner diameter of the first shaft segment (111) gradually decreases, and the inner diameter of the third shaft segment (113) gradually increases.

4. The harmonic reducer according to claim 3, characterized in that, The flexible bearing (22) is provided on the inner side of the second shaft segment (112), satisfying s1=0.5*(D c -d1), d1=|k1*H+D r +k2 |,0 <H<H1,k1=-0.087798,k2=-0.114; Wherein, s1 is the wall thickness of the transmission part (11) at the first shaft section (111), and D c d1 is the outer diameter of the transmission part (11), d1 is the inner diameter of the first shaft segment (111), H1 is the axial length of the first shaft segment (111), H is the axial length between any cross section of the transmission part (11) and the preset end face (14), and D r k1 and k2 are coefficients, representing the diameter of the outer ring of the flexible bearing (22); the preset end face (14) is the end face of the transmission part (11) near the first shaft segment (111).

5. The harmonic reducer according to claim 4, characterized in that, Satisfying s² = 0.5*(D) c -d2), d2=|k3*D r |, H1 <H<H2,k3=-0.9995; Wherein, s2 is the wall thickness of the transmission part (11) at the second shaft section (112), d2 is the inner diameter of the second shaft section (112), H2 is the axial length of the second shaft section (112), and k3 is a coefficient.

6. The harmonic reducer according to claim 5, characterized in that, full foot s3=0.5*(D c -d3), d3 = |k4*H+D r +k5|, H2 <H<H3,k4=0.034954,k5=0.285; Wherein, s3 is the wall thickness of the transmission part (11) at the third shaft section (113), d3 is the inner diameter of the third shaft section (113), H3 is the axial length of the third shaft section (113), and k4 and k5 are coefficients.

7. The harmonic reducer according to claim 1, characterized in that, The cam (211) and the hollow shaft (21) are coaxially arranged; The taper of the first conical structure is ε1, which satisfies 2.5°≤ε1≤3.5°; The taper of the second conical structure is ε2, which satisfies 2.5°≤ε2≤3.5°.

8. The harmonic reducer according to claim 1, characterized in that, The first tapered structure comprises two, and the two first tapered structures are symmetrical about the central cross-section of the cam (211); the second tapered structure comprises two, and the two second tapered structures are symmetrical about the central cross-section of the inner ring of the flexible bearing (22); The two first conical structures are connected at their smallest outer diameter ends, and the two second conical structures are connected at their largest inner diameter ends; or the two first conical structures are connected at their largest outer diameter ends, and the two second conical structures are connected at their smallest inner diameter ends.

9. The harmonic reducer according to claim 1, characterized in that, The flexible wheel (1) also includes a transition section (12) and a connecting section (13), and the transmission section (11), the transition section (12) and the connecting section (13) are arranged and connected in sequence; the harmonic reducer (3) also includes a rigid wheel (32), a rigid wheel flange (31) and a rigid bearing (33); The rigid wheel (32) has internal teeth and is sleeved on the outside of the flexible wheel (1), and the internal teeth mesh with the external teeth (114); the rigid wheel flange (31) is disposed at one end of the rigid wheel (32) and connected to the rigid wheel (32), and the rigid wheel flange (31) is located on the side of the transmission part (11) away from the transition part (12); The rigid bearing (33) is disposed at the other end of the rigid wheel (32) away from the rigid wheel flange (31) and connected to the rigid wheel (32). The rigid bearing (33) is sleeved on the outside of the transition part (12), and the end of the rigid bearing (33) away from the rigid wheel (32) is connected to the connecting part (13).

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