Flexible bearings for external gear harmonic transmission devices

Abstract

The present invention discloses a flexible bearing for an external-tooth harmonic drive device, comprising a flexible outer ring and a flexible inner ring, a cage connected between the two rings, a plurality of rollers disposed on the cage, an unevenly thick flexible inner ring, a uniformly thick outer ring, flexspline teeth disposed on the outer ring, and an input rotor sleeved within the inner ring. The outer wall of the input rotor is circular to drive the deformation of the flexible inner ring. The present invention effectively reduces assembly difficulty, simplifies the assembly process, and significantly improves assembly precision.

Description

Technical Field

[0001] The present invention relates to the technical field of harmonic gear transmission, and in particular to a flexible bearing for an external gear harmonic transmission device. Background Art

[0002] The external gear harmonic drive is a gear transmission mechanism that relies on elastic deformation motion to achieve transmission, such as Figure 1 As shown, existing external-tooth harmonic transmission devices generally consist of a rigid wheel 1, a flexspline 2, a flexible bearing 4, and an elliptical wave generator 3 that causes radial deformation of the flexspline 2. During assembly, the flexible bearing 4 is sleeved onto the outside of the wave generator 3, which is then mounted inside the flexspline 2. Rotation of the wave generator 3 causes deformation of the flexible bearing 4 and the flexspline 2, thereby meshing the flexspline 2 with the rigid wheel 1 and achieving transmission. However, this structure is complex to assemble and requires high assembly precision, making it difficult to assemble, and thus unable to effectively guarantee assembly precision. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a flexible bearing for an external gear harmonic transmission device, which can effectively reduce the difficulty of assembly, simplify the assembly process, and help improve the assembly accuracy.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A flexible bearing for an external-tooth harmonic transmission device comprises a flexible outer ring and a flexible inner ring, wherein a retaining frame is connected between the flexible outer ring and the flexible inner ring, a plurality of rollers are provided on the retaining frame, the wall thickness of the flexible inner ring is unevenly set, the wall thickness of the flexible outer ring is uniformly set, the flexible outer ring is provided with flexspline teeth, the interior of the flexible inner ring is used to sleeve an input rotor, and the outer wall of the input rotor is circular to drive the flexible inner ring to deform.

[0006] In one embodiment, the outer wall of the flexible inner ring is circular, the inner wall of the flexible inner ring is elliptical, the inner wall of the flexible outer ring is circular, and flexible gear teeth are provided on the outer wall of the flexible outer ring.

[0007] In one embodiment, the flexspline teeth and the flexible outer ring are integrally formed or separately formed.

[0008] In one embodiment, the roller is spherical or cylindrical.

[0009] In one embodiment, the retaining frame is provided with a plurality of grooves, and the roller is placed in each of the grooves.

[0010] In one embodiment, the groove is an open groove.

[0011] In one embodiment, the opening groove is an arc-shaped groove.

[0012] In one embodiment, the plurality of rollers are arranged in one row or two rows.

[0013] In one embodiment, the flexible outer ring is a deformable metal ring or plastic ring, and the flexible inner ring is also a deformable metal ring or plastic ring.

[0014] The present invention has the following beneficial effects: the flexible bearing of the present invention has the functions of a bearing, a flexible wheel and a wave generator. When used in an external tooth harmonic transmission device, there is no need to install a wave generator and a flexible wheel separately, thereby greatly reducing the assembly difficulty, simplifying the assembly process, greatly improving the assembly accuracy, and reducing the processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of an external gear harmonic transmission device in the prior art;

[0016] Figure 2 is a schematic structural diagram of the flexible bearing of the present invention;

[0017] Figure 3 yes Figure 2 A cross-sectional view of a flexible bearing in the AA direction is shown;

[0018] Figure 4 yes Figure 2 A cross-sectional view of another flexible bearing in the AA direction is shown;

[0019] Figure 5 yes Figure 2 A cross-sectional view of another flexible bearing in the AA direction is shown;

[0020] Figure 6 yes Figure 2 Schematic diagram of the assembly process of the flexible bearing and the input rotor shown;

[0021] Figure 7 yes Figure 6 The structural diagram of the flexible bearing and the input rotor after assembly is completed is shown;

[0022] Figure 8 1 is a schematic structural diagram of the external gear harmonic transmission device of the present invention;

[0023] Figure 9 3D exploded diagram of the external gear harmonic transmission device of the present invention;

[0024] In the figure: 1, rigid wheel, 11, internal teeth, 2, flexspline, 3, wave generator, 4, flexible bearing, 41, flexible outer ring, 411, flexspline teeth, 42, flexible inner ring, 43, cage, 431, groove, 44, roller, 5, input rotor, 6, input shaft. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0026] like Figure 2 As shown, this embodiment discloses a flexible bearing 4, including a flexible outer ring 41 and a flexible inner ring 42, a retaining frame 43 is connected between the flexible outer ring 41 and the flexible inner ring 42, a plurality of rollers 44 are provided on the retaining frame 43, the wall thickness of the flexible inner ring 42 is unevenly set, and the wall thickness of the flexible outer ring 41 is uniformly set, and the flexible outer ring 41 is provided with flexible wheel teeth 411 to engage with the internal teeth 11 on the rigid wheel 1, and the interior of the flexible inner ring 42 is used to sleeve the input rotor 5 (power source), and the outer wall of the input rotor 5 is circular to drive the flexible inner ring 42 to deform.

[0027] Among them, the inner wall of the flexible outer ring 41 is circular, and the outer wall of the flexible outer ring 41 is provided with flexible wheel teeth 411 to engage with the inner teeth 11 on the rigid wheel 1. The outer wall of the flexible inner ring 42 is circular, and the inner wall of the flexible inner ring 42 is elliptical to achieve an uneven wall thickness setting of the flexible inner ring 42.

[0028] The flexible inner ring 42 in the flexible bearing and the input rotor 5 serving as the power source can be connected by interference fit, bonding, keyway connection or locking.

[0029] It can be understood that the flexible outer ring 41 and the flexible inner ring 42 are both made of flexible materials so as to be deformed to a certain extent during movement.

[0030] In one embodiment, the flexspline teeth 411 and the flexible outer ring 41 are integrally formed to facilitate processing and improve processing accuracy. For example, the flexspline teeth 411 and the flexible outer ring 41 can be integrally formed by injection molding, which can greatly reduce processing costs.

[0031] In one embodiment, the roller 44 is spherical or cylindrical.

[0032] In one embodiment, Figure 9 As shown, a plurality of grooves 431 are provided on the retaining frame 43 , and a roller 44 is placed in each groove 431 .

[0033] In one embodiment, the groove 431 is an open groove.

[0034] In one embodiment, the opening groove is an arc-shaped groove.

[0035] In one embodiment, the plurality of rollers 44 are arranged in one row or two rows, for example, they may be double-row rollers or needle bearings.

[0036] In one embodiment, the flexible outer ring 41 is a deformable metal ring or plastic ring, and the flexible inner ring 42 is also a deformable metal ring or plastic ring.

[0037] The flexible bearing 4 of this embodiment can be Figure 3 The cup type shown, Figure 4 The top hat type shown or Figure 5 The pancake type shown is suitable for different harmonic drive devices. Figure 3-Figure 5 It can be seen that the wall thickness of the flexible inner ring 42 is uneven. The connection hole position at the bottom of the flexible outer ring 41 of the cup-shaped and top-hat-shaped flexible bearings should be consistent with the connection hole position at the bottom of the original flexible wheel of the external gear harmonic transmission device; the height of the flexible inner ring 42 of the pancake-shaped flexible bearing should be twice the height of the traditional flexible bearing, and the bearing should be a double-row roller or needle roller bearing.

[0038] like Figure 8-Figure 9 As shown, this embodiment also discloses an external tooth harmonic transmission device, comprising the flexible bearing 4 described in any one of the above items, an input rotor 5 and a rigid wheel 1, the rigid wheel 1 is provided with internal teeth 11 for meshing with the flexible wheel teeth 411 of the flexible bearing 4, the outer wall of the input rotor 5 is circular, the input rotor 5 is sleeved on the flexible inner ring 42 of the flexible bearing 4, the flexible bearing 4 is sleeved inside the rigid wheel 1, and the input rotor 5 is connected to the input shaft 6.

[0039] In addition, the outer wall of the input rotor 5 of this embodiment only needs to be processed into a circle, avoiding the use of the elliptical structure of the conventional wave generator in the prior art, and greatly reducing the processing difficulty and cost.

[0040] The external-tooth harmonic transmission device may be an external-tooth harmonic reducer.

[0041] The working principle of the flexible bearing of this embodiment is as follows: Figure 6 As shown, when the input rotor 5 is installed in the flexible bearing 4, since the outer wall of the input rotor 5 is circular and the wall thickness of the flexible outer ring 42 is uneven, the elliptical inner wall of the flexible inner ring 42 will be stretched into a circle by the outer wall of the input rotor 4 (the long axis of the elliptical inner wall is compressed inward and the short axis is stretched outward). Figure 6The direction of the middle arrow is the deformation direction of the flexible bearing 4. Since the wall thickness of the flexible inner ring 42 is uneven, the outer wall of the flexible inner ring 42 becomes an ellipse after being expanded. The endpoint of the major axis of the ellipse is located at the thickest part of the wall thickness of the flexible inner ring 42, and the endpoint of the minor axis is located at the thinnest part of the wall thickness of the flexible inner ring 42. Correspondingly, the flexible outer ring 41 also becomes an ellipse under the action of the roller 44. The structure of the flexible bearing 4 after expansion is as shown in FIG. Figure 7 As shown. When the flexible bearing 4 is working in the external gear harmonic drive device, the input rotor 5 drives the flexible inner ring 42 to rotate together, so that the major and minor axis positions of the ellipse formed after the flexible outer ring 41 is expanded continuously change, so that the flexible spline teeth 411 at different positions engage with the internal teeth 11 of the rigid wheel 1, thereby driving the rigid wheel 1 to rotate. During this process, the flexible spline teeth 411 at the major axis of the ellipse formed after the flexible outer ring 41 is expanded engage with the internal teeth 11 on the rigid wheel 1, and the flexible spline teeth 411 at the minor axis disengage from the internal teeth 11 on the rigid wheel 1. In addition, the input rotor 5 and the flexible inner ring 42 remain relatively stationary (rotating synchronously), thereby avoiding the problem of fracture due to stress concentration at the thinner wall of the flexible inner ring 42.

[0042] In the above process, the elliptical deformation of the flexible outer ring 41 caused by the cooperation of the input rotor 5 with a circular outer wall and the flexible inner ring 42 with uneven wall thickness is used to directly drive the rotation of the external rigid wheel 1. The entire driving process does not require the additional provision of a wave generator and a flexible wheel. This completely changes the structure of the external tooth harmonic transmission device in the prior art, which must be composed of a rigid wheel, a flexible wheel, a flexible bearing and a wave generator, and changes the way in which the rigid wheel must be driven to rotate by a wave generator. It also solves the problem of the external tooth harmonic transmission device in the prior art being difficult to assemble and the inability to ensure assembly accuracy. At the same time, the outer wall of the input rotor 5 is circular, avoiding the elliptical structure in the prior art, which also greatly reduces the machining difficulty and production cost of the rotor.

[0043] The external tooth harmonic transmission mechanism in traditional technology requires the use of an input rotor and a wave generator as active parts, and a flexible bearing as a completely passive part. However, this application directly changes the structure of the traditional flexible bearing. The inner ring of the traditional flexible bearing has a uniform wall thickness, while this application designs the inner ring of the flexible bearing to be an elliptical structure with uneven wall thickness, so that the flexible bearing can generate mechanical waves by itself while retaining the bearing function. The flexible bearing has changed from a completely passive part in the past to a semi-active part, and can actively generate mechanical waves while passively assuming the bearing function.

[0044] The flexible outer ring 41 in the flexible bearing of this embodiment plays the role of both the outer ring of the bearing and the role of the flexible wheel in the prior art. The flexible inner ring 42 plays the role of both the inner ring of the bearing and the role of the wave generator in the prior art. Therefore, when the flexible bearing 4 of this embodiment is used in the external tooth harmonic reduction device, there is no need to install the wave generator 3 and the flexible wheel 2 separately, which greatly reduces the assembly difficulty and simplifies the assembly process. At the same time, since the functions of the wave generator and the flexible wheel can be directly realized on the flexible bearing, the assembly accuracy is greatly improved and the processing cost is reduced.

[0045] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A flexible bearing for an external gear harmonic transmission device, characterized in that: The flexible outer ring comprises a flexible inner ring, a retainer being connected between the flexible outer ring and the flexible inner ring, a plurality of rollers being provided on the retainer, the wall thickness of the flexible inner ring being uneven, the wall thickness of the flexible outer ring being uniform, the flexible outer ring being provided with flexspline teeth, the interior of the flexible inner ring being used to sleeve an input rotor, the outer wall of the input rotor being circular to drive the flexible inner ring to deform; The outer wall of the flexible inner ring is circular, the inner wall of the flexible inner ring is elliptical, the inner wall of the flexible outer ring is circular, and flexible gear teeth are provided on the outer wall of the flexible outer ring.

2. The flexible bearing according to claim 1, characterized in that: The flexspline teeth and the flexible outer ring are integrally formed or separately formed.

3. The flexible bearing according to claim 1, wherein: The roller is spherical or cylindrical.

4. The flexible bearing according to claim 1, wherein: The retaining frame is provided with a plurality of grooves, and the roller is placed in each of the grooves.

5. The flexible bearing according to claim 4, characterized in that: The groove is an open groove.

6. The flexible bearing according to claim 5, characterized in that: The opening groove is an arc-shaped groove.

7. The flexible bearing according to claim 1, wherein: The plurality of rollers are arranged in one row or two rows.

8. The flexible bearing according to claim 1, wherein: The flexible outer ring is a deformable metal ring or plastic ring, and the flexible inner ring is also a deformable metal ring or plastic ring.

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