Improved speed reducer

Abstract

The invention relates to an improved speed reducer which comprises a base body. The input shaft is rotatably arranged in the mounting cavity and is provided with a transmission wave surface of which the lower surface is fluctuant; the output shaft is provided with a first gear ring opposite to the transmission wave surface; an outer ring of the flexible gear is restrained in the mounting cavity, an inner ring of the flexible gear is clamped between the transmission wave surface and the first gear ring, and the lower surface of the inner ring is provided with a second gear ring which can be driven by the transmission wave surface to generate local deformation so as to be meshed with or separated from the first gear ring; the positioning piece is arranged close to the inner wall face of the base body, first positioning teeth are arranged on the top of the positioning piece, and second positioning teeth meshed with the first positioning teeth for limiting are arranged on the lower surface of the flexible gear outer ring. The meshing limiting between the flexible gear outer ring and the positioning piece increases the force transmission surface, and when the partial deformation of the flexible gear inner ring transmits the circumferential unbalanced force to the flexible gear outer ring, the force transmission and dispersion can be carried out by means of the meshing relationship, so that the stress of each part of the flexible gear positioning surface is uniform, and the problem of local cracking of the flexible gear is avoided.

Description

Technical Field

[0001] This invention relates to the field of speed reducer technology, specifically to an improved speed reducer. Background Technology

[0002] Currently, reduction structures based on the principle of low tooth difference reduction are relatively mature in existing technologies.

[0003] The applicant's earlier application CN202211549585.3, "A Reducer," discloses a structure including a housing, an input shaft, a pulsator, an output component, and an elastic gear. The elastic gear is located within a cavity and sleeved around the periphery of the input shaft. Its outer circumference is fixedly connected to the housing. Along the axial direction of the input shaft, its position near the inner circumference is located between the pulsator and the output component. Driven by the pulsator, it locally undergoes elastic deformation along the axial direction of the input shaft towards the output component, thereby driving the output component to rotate around the axis of the input shaft. In the above solution, the elastic gear can undergo local deformation along the axial direction of the output shaft under relatively small forces, thereby ensuring the load-bearing capacity of the reducer while reducing losses.

[0004] To constrain the position of the elastic gear, the aforementioned elastic gear is inserted into the housing via its outer ring segment and positioned using a locking screw aligned with the axial direction of the elastic gear. During transmission, the elastic gear undergoes localized deformation, resulting in significant differences in force across the inner ring segment in the circumferential direction. This force is transmitted to the outer ring segment. Due to the small contact area between the locking screw and the outer ring segment, long-term uneven stress on the outer ring segment can easily lead to localized cracking of the elastic gear, severely impacting its service life. Furthermore, the head of the locking screw needs to occupy a certain height in the axial direction, requiring a space to be machined in the housing to accommodate the screw head, which is inconvenient for production and assembly.

[0005] Therefore, the current reducer structure needs further improvement. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide an improved reducer that can make the flexural gear positioning surface uniformly stressed, thereby avoiding local cracking and improving service life, in light of the current state of the prior art.

[0007] The second technical problem to be solved by the present invention is to provide an improved speed reducer that is easy to manufacture and assemble, in light of the current state of the prior art.

[0008] The technical solution adopted by the present invention to solve at least one of the above-mentioned technical problems is as follows:

[0009] An improved speed reducer includes:

[0010] The substrate has an installation cavity;

[0011] An input shaft is at least partially rotatably disposed in a mounting cavity and is provided with a transmission wave surface arranged circumferentially and having an undulating lower surface. The transmission wave surface includes at least two downward protrusions and two upward arches. The protrusions and arches are arranged alternately and smoothly connected in the circumferential direction of the input shaft.

[0012] The output shaft is rotatably disposed below the transmission wave surface and has a first gear ring opposite to the transmission wave surface;

[0013] The flexible wheel has an outer ring constrained in the mounting cavity and an inner ring sandwiched between the transmission wave surface and the first gear ring. The lower surface of the inner ring is provided with a second gear ring that can undergo local deformation under the drive of the transmission wave surface, thereby engaging or disengaging with the first gear ring.

[0014] It also includes a positioning element arranged close to the inner wall of the substrate, the top of which is provided with a first positioning tooth, and the lower surface of the outer ring of the flexible wheel is provided with a second positioning tooth that meshes with and limits the first positioning tooth.

[0015] With the above structure, the outer ring of the flexible wheel and the positioning component are limited by the meshing of positioning teeth. This structure increases the force transmission surface and the force is evenly distributed. When the inner ring of the flexible wheel deforms locally and transmits the uneven force in the circumferential direction to the outer ring of the flexible wheel, the force can be transmitted and dispersed by the meshing relationship between the teeth, so that the force is evenly distributed on the positioning surface of the flexible wheel, thereby avoiding the problem of local cracking of the flexible wheel.

[0016] Preferably, the first positioning teeth consist of several teeth that at least cover a partial area of ​​the top of the positioning member, and correspondingly, the second positioning teeth consist of several teeth that at least cover a partial area of ​​the lower surface of the outer ring of the flexible wheel. Due to the greatly increased contact surface caused by the meshing relationship between the teeth, even if the meshing structure of the teeth does not completely cover the entire circumferential direction, it can still achieve good positioning and uniform force transmission.

[0017] Further preferably, several of the first positioning teeth are arranged sequentially in the circumferential direction of the positioning member to form a third toothed ring. Correspondingly, several of the second positioning teeth cover the circumferential direction of the flexible wheel outer ring and form a fourth toothed ring. This forms a tooth-to-tooth meshing structure that covers the circumferential direction, which can maximize the force transmission surface and obtain the best positioning reliability and balanced force transmission effect.

[0018] To improve the compactness and reliability of the positioning of the outer ring of the flexible wheel, the diameter of the mounting cavity above the flexible wheel is smaller than the diameter below it, and a stepped surface is formed at the joint, which abuts against the upper surface of the outer ring of the flexible wheel.

[0019] Preferably, the first positioning tooth is arranged near the outer edge of the upper surface of the positioning member, and the second positioning tooth is arranged near the outer edge of the outer ring of the flexspline. After the first and second positioning teeth mesh, the outer surface of the integral structure is arranged close to the inner wall of the mounting cavity. This structure helps to improve the compactness and reliability of the assembly between the positioning structure and the mounting cavity, thereby avoiding unorienting deformation of the outer ring of the flexspline.

[0020] Preferably, the stepped surface extends radially inward from its center to form a first inclined surface. The stepped surface located on the periphery of the first inclined surface presses against the upper surface of the flexure, and the radial width of the formed pressing surface is greater than the radial width of the first positioning tooth and / or the second positioning tooth. This structure helps to ensure the clamping effect on the outer ring of the flexure.

[0021] As an improvement, the positioning member is formed in an annular shape with its outer surface close to the inner wall of the mounting cavity. A limiting member is provided in the mounting cavity to axially limit the positioning member against the inner wall of the cavity. Preferably, the positioning member has a positioning hole extending radially through it. A screw passes through this positioning hole and locks itself against the inner wall of the mounting cavity; the screw constitutes the limiting member. This structure achieves axial limiting of the flexible wheel radially, which is not only unrestricted by height space, facilitating production and assembly, but also provides excellent axial limiting of the flexible wheel, ensuring uniform force distribution on both the upper and lower surfaces of the flexible wheel's outer ring.

[0022] Preferably, a transmission assembly capable of rolling contact between the transmission wave surface and the upper surface of the inner ring of the flexspline is provided. This transmission assembly includes multiple independent rollers and independent cages, with a roller positioned between two adjacent cages. The cages are used to limit the position of the rollers. Setting the transmission assembly as multiple independent rollers and cages allows for a closer fit between the rollers and the transmission wave surface, improving transmission accuracy.

[0023] Preferably, the roller is formed as a cylindrical structure extending radially along the flexure, the side of the cage is formed as a figure-eight structure, and an oil groove is formed between the opposing surfaces of two adjacent cages to constrain the rotation of a roller. This structure facilitates lubrication of the roller, ensuring its continuous and flexible operation.

[0024] Preferably, the inner and outer edges of the transmission wave surface are respectively provided with downwardly extending protrusions, and a limiting groove for constraining the upper end of the transmission assembly is formed between the inner and outer protrusions. This structure facilitates the limiting of independent rollers and cages, and improves the reliability of the engagement between the transmission assembly and the flexspline.

[0025] Further preferably, the lower surface of the convex edge forms a floating structure that conforms to the undulation trend of the transmission wave surface. Setting the undulation trend of the convex edge and the transmission wave surface to be the same can maintain the stability of the radial centrifugal force, which is beneficial to improving the force transmission accuracy.

[0026] Preferably, a transmission sleeve extending downward into the mounting cavity is provided at the central part of the input shaft, and the output shaft is spaced around the outer periphery of the transmission sleeve and rotates with the outer circumference of the transmission sleeve through a tapered roller bearing with a smaller upper end and a larger lower end. Compared with the multi-part transmission structure in the prior art, this structure is simple, easy to manufacture, and conducive to increasing load capacity.

[0027] Preferably, the inner cavity of the output shaft forms a tapered structure with a smaller upper end and a larger lower end, and the inner wall of the output shaft is machined integrally with the outer ring of the tapered roller bearing. This structure helps to further improve the reliability of the component fit and increase the load capacity.

[0028] To facilitate the constraint of the tapered roller bearing, a locking member is threadedly connected to the lower end of the transmission sleeve. The periphery of this locking member rests against the tapered roller bearing via a washer, thereby limiting the axial position of the tapered roller bearing. Compared to the large locking nuts in the prior art, this structure reduces the restriction on axial length.

[0029] Preferably, the flexible wheel is provided with radially extending opening slots, and there are at least two sets of opening slots arranged at intervals in the circumferential direction of the flexible wheel. This structure can reduce the deformation force of the flexible wheel, making it easier for the flexible wheel to undergo local deformation and reset in the circumferential direction, thereby further improving the service life of the flexible wheel.

[0030] Compared with the prior art, the advantages of the present invention are as follows: The present invention provides a positioning component for positioning the outer ring of the flexible wheel in the mounting cavity of the base. The outer ring of the flexible wheel and the positioning component are limited by the meshing of positioning teeth. This structure increases the force transmission surface and the force is evenly distributed. When the inner ring of the flexible wheel is locally deformed and the uneven force in the circumferential direction is transmitted to the outer ring of the flexible wheel, the force can be transmitted and dispersed by the meshing relationship between the teeth, so that the force is evenly distributed on the positioning surface of the flexible wheel, thereby avoiding the problem of local cracking of the flexible wheel and improving the service life of the flexible wheel. The improved positioning structure does not require axial locking with screws and does not require relief holes to be opened in the base or corresponding structure, which facilitates production and assembly. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0032] Figure 2 for Figure 1 Another angle view;

[0033] Figure 3 This is a cross-sectional view of Embodiment 1 of the present invention;

[0034] Figure 4 for Figure 3 Enlarged view of section A;

[0035] Figure 5 for Figure 4 Another angle view;

[0036] Figure 6 This is an exploded view of Embodiment 1 of the present invention;

[0037] Figure 7 This is a partial structural diagram of the transmission assembly in Embodiment 1 of the present invention;

[0038] Figure 8 This is a schematic diagram of the input shaft in Embodiment 1 of the present invention;

[0039] Figure 9 This is a schematic diagram of the flexible wheel in Embodiment 2 of the present invention. Detailed Implementation

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] In the description of this invention, it should be understood that if terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0042] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact, or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. Where applicable, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this invention are for illustrative purposes only and do not represent the only possible implementation.

[0046] Example 1:

[0047] like Figures 1-8 As shown, the improved reducer in this embodiment includes a base 1, an input shaft 2, an output shaft 3, a flexible wheel 4, and a positioning component 5.

[0048] The base 1 is provided with a mounting cavity 11; the input shaft 2 is rotatably disposed in the mounting cavity 11 at least partially, and is provided with a transmission wave surface 21 arranged circumferentially and having an undulating lower surface. The specific structure of the transmission wave surface 21 is consistent with the applicant's prior application CN202211549585.3, and will not be described in detail here; the output shaft 3 is rotatably disposed below the transmission wave surface 21 and has a first gear ring 31 opposite to the transmission wave surface 21; the outer ring 41 of the flexible wheel 4 is constrained in the mounting cavity 11, and the inner ring 42 is clamped between the transmission wave surface 21 and the first gear ring 31. The lower surface of the inner ring 42 is provided with a second gear ring 43 that can undergo partial deformation under the drive of the transmission wave surface 21, thereby engaging or disengaging with the first gear ring 31; the positioning member 5 is arranged close to the inner wall of the base 1, and the top of the positioning member 5 is provided with a first positioning tooth 51. The lower surface of the outer ring 41 of the flexible wheel 4 is provided with a second positioning tooth 44 that engages and limits the first positioning tooth 51.

[0049] In this embodiment, the flexible wheel 4 is annular and made of deformable and repositionable metal sheet. The body of the flexible wheel 4 in this embodiment adopts a planar structure, but it can also adopt an inclined structure as in CN202211549585.3.

[0050] In this embodiment, the transmission wave surface 21 includes at least two downward protruding portions and two upward arched portions. The protruding portions and arched portions are staggered and smoothly connected around the input shaft. Figure 8 The transmission wave surface 21 shown is composed of three downward protrusions and three upward arches that are alternately connected. It is understood that other numbers of downward protrusions and upward arches can be provided according to transmission requirements such as transmission ratio.

[0051] With the above structure, the outer ring 41 of the flexible wheel 4 is limited by the meshing of the positioning teeth. This structure increases the force transmission surface and the force is evenly distributed. When the inner ring 42 of the flexible wheel 4 is locally deformed and the unbalanced force in the circumferential direction is transmitted to the outer ring 41 of the flexible wheel 4, the force can be transmitted and distributed by the meshing relationship between the teeth, so that the force is evenly distributed on the positioning surface of the flexible wheel 4, thereby avoiding the problem of local cracking of the flexible wheel 4.

[0052] In this embodiment, the first positioning teeth 51 are a plurality of teeth that at least cover a partial area of ​​the top of the positioning member 5, and correspondingly, the second positioning teeth 44 are a plurality of teeth that at least cover a partial area of ​​the lower surface of the outer ring 41 of the flexible wheel 4. Due to the greatly increased contact surface caused by the meshing relationship between the teeth, even if the meshing structure between the teeth does not completely cover the circumferential direction, it can still achieve a good positioning and uniform force transmission effect.

[0053] Preferably, a plurality of first positioning teeth 51 are arranged sequentially in the circumferential direction of the positioning member 5 to form a third tooth ring. Correspondingly, a plurality of second positioning teeth 44 cover the circumferential direction of the outer ring 41 of the flexible wheel 4 and form a fourth tooth ring. This forms a tooth-to-tooth meshing structure that can cover the circumferential direction, which can maximize the force transmission surface and obtain the best positioning reliability and balanced force transmission effect.

[0054] To improve the compactness and reliability of the positioning of the outer ring 41 of the flexible wheel 4, the diameter of the mounting cavity 11 above the flexible wheel 4 is smaller than the diameter below it, and a stepped surface 12 is formed at the joint, which presses against the upper surface of the outer ring 41 of the flexible wheel 4.

[0055] In this embodiment, the first positioning tooth 51 is arranged near the outer edge of the upper surface of the positioning member 5, and the second positioning tooth 44 is arranged near the outer edge of the outer ring 41 of the flexible wheel 4. After the first positioning tooth 51 and the second positioning tooth 44 mesh, the outer surface of the integral part is arranged close to the inner wall of the mounting cavity 11. This structure helps to improve the assembly compactness and reliability between the positioning structure and the mounting cavity 11, so as to avoid the non-directional deformation of the outer ring 41 of the flexible wheel 4.

[0056] The aforementioned stepped surface 12 extends radially inward from its center to form a first inclined surface 121. The stepped surface 12 located around the first inclined surface 121 presses against the upper surface of the flexible wheel 4, and the radial width of the formed pressing surface is greater than the radial width of the first positioning tooth 51 and the second positioning tooth 44. This structure helps to ensure the pressing effect on the outer ring 41 of the flexible wheel 4.

[0057] In this embodiment, the positioning member 5 is formed in an annular shape with its outer surface close to the inner wall of the mounting cavity 11. A limiting member 6 is provided in the mounting cavity 11 to axially limit the positioning member 5 to the inner wall of the mounting cavity 11. The positioning member 5 has a positioning hole 52 extending radially through it. A screw passes through the positioning hole 52 and locks itself to the inner wall of the mounting cavity 11; the screw constitutes the limiting member 6. This structure achieves axial limiting of the flexible wheel 4 radially, which is not only unrestricted by height space, facilitating production and assembly, but also provides a good axial limiting effect on the flexible wheel 4, ensuring uniform force on both the upper and lower surfaces of the outer ring 41 of the flexible wheel 4.

[0058] In this embodiment, a transmission assembly 7 is provided between the transmission wave surface 21 and the upper surface of the inner ring 42 of the flexible wheel 4, which can roll with both. The transmission assembly 7 includes multiple independent rollers 71 and independent cages 72. A roller 71 is disposed between two adjacent cages 72, and the cages 72 are used to limit the position of the rollers 71. By setting the transmission assembly 7 as multiple independent rollers 71 and cages 72, the fit between the rollers 71 and the transmission wave surface 21 can be more precise, thereby improving the transmission accuracy.

[0059] The roller 71 is formed as a cylindrical structure extending radially along the flexible wheel 4, and the side of the cage 72 is formed as a figure-eight structure. An oil groove 73 is formed between the opposing surfaces of two adjacent cages 72 to constrain the rotation of a roller 71. This structure facilitates lubrication of the roller 71 and ensures its flexible operation.

[0060] In this embodiment, the inner and outer edges of the transmission wave surface 21 are respectively provided with downwardly extending protrusions 22, and a limiting groove 23 is formed between the inner and outer protrusions 22 to constrain the upper end of the transmission assembly 7. This structure facilitates the limiting of the independent rollers 71 and the cage 72, improving the reliability of the engagement between the transmission assembly 7 and the transmission wave surface 21 and the flexible wheel 4. The lower surface of the aforementioned protrusions 22 forms a floating structure 221 that conforms to the undulation trend of the transmission wave surface 21. Setting the undulation trend of the protrusions 22 and the transmission wave surface 21 to be the same structure can maintain the stability of the radial centrifugal force, which is beneficial to improving the force transmission accuracy.

[0061] In this embodiment, a transmission sleeve 24 is provided at the center of the input shaft 2, extending downward into the mounting cavity 11. The output shaft 3 is spaced around the transmission sleeve 24 and rotates with the outer circumference of the transmission sleeve 24 through a tapered roller bearing 8 with a smaller upper end and a larger lower end. Compared with the multi-part transmission structure in the prior art, this structure is simple, easy to manufacture, and beneficial for increasing load capacity.

[0062] In this embodiment, the inner cavity of the output shaft 3 is formed into a tapered structure with a smaller upper end and a larger lower end, and the inner wall of the output shaft 3 is machined integrally with the outer ring 41 of the tapered roller bearing 8. This structure helps to further improve the reliability of the component fit and increase the load capacity.

[0063] To facilitate the constraint of the tapered roller bearing 8, a locking member 25 is threadedly connected to the lower end of the transmission sleeve 24. The periphery of the locking member 25 rests against the tapered roller bearing 8 via a washer 26, thereby limiting the axial position of the tapered roller bearing 8. Compared with the large locking nut in the prior art, this structure reduces the restriction on axial length.

[0064] In this embodiment, a positioning element 5 is provided in the mounting cavity 11 of the base 1 for positioning the outer ring 41 of the flexible wheel 4. The outer ring 41 of the flexible wheel 4 and the positioning element 5 are limited by the meshing of positioning teeth. This structure increases the force transmission surface and the force is evenly distributed. When the inner ring 42 of the flexible wheel 4 is locally deformed and the uneven force in the circumferential direction is transmitted to the outer ring 41 of the flexible wheel 4, the force can be transmitted and distributed by the meshing relationship between the teeth, so that the force is evenly distributed on the positioning surface of the flexible wheel 4, thereby avoiding the problem of local cracking of the flexible wheel 4 and improving the service life of the flexible wheel 4. The improved positioning structure does not require axial locking with screws and does not require relief holes to be opened on the base 1 or the corresponding structure, which facilitates production and assembly.

[0065] The reducer in this embodiment can be used at the joints of an intelligent robot to provide precise force transmission for the robot's fine movements.

[0066] Example 2:

[0067] The difference between this embodiment and Embodiment 1 is that: Figure 9 As shown, the flexible wheel 4 in this embodiment is provided with radially extending opening slots 45, which are vertically continuous. Multiple sets of opening slots 45 are arranged at intervals along the circumference of the flexible wheel 4. This structure reduces the deformation force of the flexible wheel, making it easier for the flexible wheel to undergo local deformation and recovery in the circumferential direction, further improving the service life of the flexible wheel. Furthermore, with this structure, due to the better deformation effect of the flexible wheel, the thickness of the main body of the flexible wheel can be increased. For example, the thickness of the main body of the flexible wheel in this embodiment can be more than twice the thickness of the main body of the flexible wheel in Embodiment 1, greatly improving the stiffness and load-bearing capacity of the flexible wheel, thereby increasing the output load of the reducer and meeting the needs of more industries.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An improved speed reducer, comprising: The substrate (1) is provided with an installation cavity (11); The input shaft (2) is at least partially rotatably disposed in the mounting cavity (11) and is provided with a transmission wave surface (21) arranged circumferentially and having an undulating lower surface. The transmission wave surface (21) includes at least two downward protrusions and two upward arches. The protrusions and arches are arranged alternately and smoothly connected in the circumferential direction of the input shaft. The output shaft (3) is rotatably disposed below the transmission wave surface (21) and has a first gear ring (31) opposite to the transmission wave surface (21); The flexible wheel (4) has an outer ring (41) constrained in the mounting cavity (11) and an inner ring (42) sandwiched between the transmission wave surface (21) and the first gear ring (31). The lower surface of the inner ring (42) is provided with a second gear ring (43) that can undergo local deformation under the drive of the transmission wave surface (21) to engage or disengage with the first gear ring (31). The feature is that it further includes a positioning member (5) arranged close to the inner wall of the substrate (1), the top of the positioning member (5) is provided with a first positioning tooth (51), and the lower surface of the outer ring (41) of the flexible wheel (4) is provided with a second positioning tooth (44) that meshes with and limits the first positioning tooth (51).

2. The improved reducer according to claim 1, characterized in that: The first positioning teeth (51) are a plurality of teeth that at least cover a local area of ​​the top of the positioning member (5), and correspondingly, the second positioning teeth (44) are a plurality of teeth that at least cover a local area of ​​the lower surface of the outer ring (41) of the flexible wheel (4).

3. The improved reducer according to claim 2, characterized in that: Several first positioning teeth (51) are arranged sequentially in the circumferential direction of the positioning member (5) to form a third tooth ring. Correspondingly, several second positioning teeth (44) cover the circumferential direction of the outer ring (41) of the flexible wheel (4) and form a fourth tooth ring.

4. The improved reducer according to claim 1, characterized in that: The mounting cavity (11) is located above the flexible wheel (4) with a smaller diameter than the diameter below it and forms a stepped surface (12) at the joint, which presses against the upper surface of the outer ring (41) of the flexible wheel (4).

5. The improved reducer according to claim 4, characterized in that: The first positioning tooth (51) is arranged near the outer edge of the upper surface of the positioning member (5), and the second positioning tooth (44) is arranged near the outer edge of the outer ring (41) of the flexible wheel (4). After the first positioning tooth (51) and the second positioning tooth (44) mesh, the outer surface of the integral is arranged close to the inner wall of the mounting cavity (11).

6. The improved reducer according to claim 4, characterized in that: The stepped surface (12) extends radially inward from its middle part to form a first inclined surface (121). The stepped surface (12) located on the periphery of the first inclined surface (121) presses against the upper surface of the flexible wheel (4), and the radial width of the formed pressing surface is greater than the radial width of the first positioning tooth (51) and / or the second positioning tooth (44).

7. The improved reducer according to claim 1, characterized in that: The positioning element (5) is formed into a ring and its outer surface is close to the inner wall of the mounting cavity (11). The mounting cavity (11) is provided with a limiting element (6) that can axially limit the positioning element (5) and the inner wall of the mounting cavity (11).

8. The improved reducer according to claim 7, characterized in that: The positioning member (5) has a positioning hole (52) that extends radially through it. The screw is inserted into the positioning hole (52) and locked to the inner wall of the mounting cavity (11). The screw constitutes the limiting member (6).

9. The improved reducer according to any one of claims 1 to 8, characterized in that: A transmission assembly (7) capable of rolling cooperation between the transmission wave surface (21) and the upper surface of the inner ring (42) of the flexible wheel (4) is provided. The transmission assembly (7) includes multiple independent rollers (71) and independent cages (72). A roller (71) is provided between two adjacent cages (72). The cages (72) are used to limit the position of the rollers (71).

10. The improved reducer according to claim 9, characterized in that: The roller (71) is formed as a cylindrical structure extending radially along the flexible wheel (4), and the side of the cage (72) is formed as a figure-eight structure. An oil groove (73) is formed between the opposite surfaces of two adjacent cages (72) for rotating and constraining a roller (71).

11. The improved reducer according to claim 9, characterized in that: The inner and outer edges of the transmission wave surface (21) are respectively provided with downwardly extending convex edges (22), and a limiting groove (23) for constraining the upper end of the transmission assembly (7) is formed between the inner and outer convex edges (22).

12. The improved reducer according to claim 11, characterized in that: The lower surface of the convex edge (22) forms a floating structure (221) that conforms to the undulation trend of the transmission wave surface (21).

13. The improved reducer according to any one of claims 1 to 8, characterized in that: The input shaft (2) has a transmission sleeve (24) that extends downward into the mounting cavity (11) at its central part. The output shaft (3) is spaced around the transmission sleeve (24) and rotates with the outer circumference of the transmission sleeve (24) through a tapered roller bearing (8) with a smaller upper end and a larger lower end.

14. The improved reducer according to claim 13, characterized in that: The inner cavity of the output shaft (3) forms a tapered structure with a small upper end and a large lower end, and the inner wall of the output shaft (3) is machined as a single unit with the outer ring (41) of the tapered roller bearing (8).

15. The improved reducer according to claim 13, characterized in that: The lower end of the transmission sleeve (24) is threadedly connected to a fastener (25), the periphery of which is abutted against the tapered roller bearing (8) by a gasket, for limiting the axial position of the tapered roller bearing (8).

16. The improved reducer according to any one of claims 1 to 8, characterized in that: The flexible wheel is provided with radially extending opening slots, and there are at least two sets of opening slots arranged at intervals in the circumferential direction of the flexible wheel.

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