Flexible bearings for internal gear harmonic transmission devices

Abstract

The present invention discloses a flexible bearing for an internal gear harmonic drive device, comprising a flexible outer ring and a flexible inner ring, a retainer connected between the flexible outer ring and the flexible inner ring, a plurality of rollers disposed on the retainer, the flexible outer ring having an uneven wall thickness, the flexible inner ring having a uniform wall thickness, and flexible spline teeth connected to the flexible inner ring. The flexible outer ring is configured to be sleeved within an input rotor, the inner wall of which is circular. 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 internal gear harmonic transmission device. Background Art

[0002] The internal gear harmonic drive is a gear transmission mechanism that relies on elastic deformation motion to achieve transmission. It is generally composed of a rigid inner wheel, a flexible outer wheel, a flexible bearing, and an elliptical wave generator that causes the flexible outer wheel to undergo radial deformation.

[0003] When assembling an internal gear harmonic drive, the following method can be used: insert the flexible bearing into the interior of the flexspline and expand the interior of the flexspline. During movement, the wave generator ellipse pushes outward to deform the flexible bearing and the flexspline. However, this structure is complex to assemble and requires high assembly precision. It is difficult to assemble and is prone to damage to the flexspline during assembly.

[0004] The specification of the patent document with Chinese patent publication number CN209370384U discloses an internal gear harmonic reducer, which consists of a flexspline, a rigid pulley and a wave generator. During assembly, the wave generator has a built-in flexible bearing installed inside the wave generator, and the flexspline is installed inside the flexible bearing. The wave generator is provided with an extrusion roller portion to squeeze the flexspline through the extrusion roller portion to cause the flexspline to deform. However, although the reducer structure relatively reduces the difficulty of installing the flexspline, the flexspline, the flexible bearing and the wave generator are all independent parts. The assembly of the flexspline and the flexible bearing, and the flexible bearing and the wave generator still requires high assembly precision, and the assembly is complex and difficult.

[0005] In summary, existing internal gear harmonic transmission devices all have the problem of being difficult to assemble and being unable to effectively ensure assembly accuracy. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a flexible bearing for an internal gear harmonic transmission device, which can effectively reduce the difficulty of assembly, simplify the assembly process, and help improve the assembly accuracy.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] A flexible bearing for an internal gear harmonic reduction 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, and a plurality of rollers are provided on the retaining frame. The wall thickness of the flexible outer ring is unevenly set, and the wall thickness of the flexible inner ring is uniformly set. The flexible inner ring is connected to flexible spline teeth. The flexible outer ring is used to be sleeved inside an input rotor, and the inner wall of the input rotor is circular.

[0009] In one embodiment, the outer wall of the flexible outer ring is elliptical, the inner wall of the flexible outer ring is circular, the outer wall of the flexible inner ring is circular, and the flexspline teeth are provided on the inner wall of the flexible inner ring.

[0010] In one embodiment, the flexspline teeth and the flexible inner ring are integrally formed or separately formed.

[0011] In one embodiment, the roller is spherical or cylindrical.

[0012] In one embodiment, the retaining frame is provided with a plurality of grooves, and the roller is placed in each of the grooves.

[0013] In one embodiment, the groove is an open groove.

[0014] In one embodiment, the opening groove is an arc-shaped groove.

[0015] In one embodiment, the plurality of rollers are arranged in one row or two rows.

[0016] 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.

[0017] 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 internal gear 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

[0018] Figure 1 is a schematic structural diagram of the flexible bearing of the present invention;

[0019] Figure 2 yes Figure 1 A cross-sectional view of a flexible bearing in the AA direction is shown;

[0020] Figure 3 yes Figure 1 A cross-sectional view of another flexible bearing in the AA direction is shown;

[0021] Figure 4 yes Figure 1 A cross-sectional view of another flexible bearing in the AA direction is shown;

[0022] Figure 5 yes Figure 1 Schematic diagram of the assembly process of the flexible bearing and the input rotor shown;

[0023] Figure 6 yes Figure 5 The structural diagram of the flexible bearing and the input rotor after assembly is completed is shown;

[0024] Figure 7 It is a structural schematic diagram of the internal gear harmonic transmission device of the present invention;

[0025] Figure 8 3D exploded diagram of the internal gear harmonic transmission device of the present invention;

[0026] In the figure: 1, flexible outer ring, 2, flexible inner ring, 21, flexspline teeth, 3, cage, 31, grooves, 4, rollers, 5, input rotor, 6, rigid wheel, 61, external teeth, 7, output shaft. DETAILED DESCRIPTION

[0027] 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.

[0028] like Figure 1 As shown, this embodiment discloses a flexible bearing for an internal tooth harmonic transmission device, including a flexible outer ring 1 and a flexible inner ring 2, a retaining frame 3 is connected between the flexible outer ring 1 and the flexible inner ring 2, a plurality of rollers 4 are arranged on the retaining frame 3, the wall thickness of the flexible outer ring 1 is unevenly set, and the wall thickness of the flexible inner ring 2 is uniformly set, and the flexible inner ring 2 is connected with a flexible wheel tooth 21 for meshing with the external teeth 61 on the rigid wheel 6, the flexible outer ring 1 is used to be sleeved on the inside of the input rotor 5 (power source), and the inner wall of the input rotor 5 is circular to drive the flexible outer ring 1 to deform.

[0029] The outer wall of the flexible outer ring 1 is elliptical, and the inner wall of the flexible outer ring 1 is circular, so that the wall thickness of the flexible outer ring 1 is unevenly set. The outer wall of the flexible inner ring 2 is circular, and the inner wall of the flexible inner ring 2 is provided with flexible gear teeth 21.

[0030] The flexible outer ring 1 in the flexible bearing and the input rotor 5 as the power source can be connected by interference fit, bonding, keyway connection or locking.

[0031] It can be understood that the flexible outer ring 1 and the flexible inner ring 2 are both made of flexible materials so as to be able to undergo certain deformation during movement.

[0032] In one embodiment, the flexspline teeth 21 and the flexible inner ring 2 are integrally formed to facilitate processing and improve machining accuracy. For example, the flexspline teeth 21 and the flexible inner ring 2 can be integrally molded using injection molding, significantly reducing processing costs. Alternatively, the flexspline teeth 21 and the flexible inner ring 2 can be formed separately, with the flexspline teeth 21 assembled onto the flexible inner ring 2 after processing.

[0033] In one embodiment, in the present invention, the flexible outer ring 1 of the flexible bearing and the input rotor 5 as the power source can be connected by interference fit, bonding, keyway connection or locking.

[0034] In one embodiment, the roller 4 is spherical or cylindrical.

[0035] In one embodiment, Figure 8 As shown, a plurality of grooves 31 are provided on the retaining frame 3 , and a roller 4 is placed in each groove 31 .

[0036] In one embodiment, the groove 31 is an open groove.

[0037] In one embodiment, the opening groove is an arc-shaped groove.

[0038] In one embodiment, the plurality of grooves 31 are evenly distributed along the circumference.

[0039] In one embodiment, the plurality of rollers 4 are arranged in one row or two rows, for example, they may be double-row rollers or needle roller bearings.

[0040] In one embodiment, the flexible outer ring 1 is a deformable metal ring or plastic ring, and the flexible inner ring 2 is also a deformable metal ring or plastic ring.

[0041] The flexible bearing of this embodiment can be Figure 2 The cup type shown, Figure 3 The top hat type shown or Figure 4 The pancake type shown is suitable for different harmonic drive devices. Figure 2-Figure 4 It can be seen that the wall thickness of the flexible outer ring 1 is uneven. The connection hole position at the bottom of the flexible inner ring 2 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 internal gear harmonic transmission device; the height of the flexible outer ring 1 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.

[0042] like Figure 7-Figure 8 As shown, this embodiment also discloses an internal tooth harmonic transmission device, comprising any of the above-mentioned flexible bearings, an input rotor 5 and a rigid wheel 6, the rigid wheel 6 being provided with external teeth 61 for engaging with the flexible wheel teeth 21 of the flexible bearing, the inner wall of the input rotor 5 being circular to facilitate compression deformation of the flexible outer ring 1, the interior of the input rotor 5 being sleeved with a flexible bearing, the flexible inner ring 2 of the flexible bearing being sleeved with a rigid wheel 6, and the rigid wheel 6 being connected to an output shaft 7.

[0043] In addition, the inner wall of the input rotor 5 of this embodiment only needs to be processed into a circle, avoiding the conventional elliptical structure in the prior art, and greatly reducing the processing difficulty and cost.

[0044] The internal gear harmonic transmission device may be an internal gear harmonic reducer.

[0045] The working principle of the flexible bearing of this embodiment is as follows: Figure 5 As shown, when the flexible bearing is installed in the input rotor 5, since the inner wall of the input rotor 5 is circular and the wall thickness of the flexible outer ring 1 is uneven, the elliptical outer wall of the flexible outer ring 1 will be compressed into a circle by the inner hole of the input rotor 5 (the long axis of the elliptical outer wall is compressed inwards and the short axis is stretched outwards). Figure 5 The direction of the middle arrow is the deformation direction of the flexible bearing. Due to the uneven wall thickness of the flexible outer ring 1, the inner wall of the flexible outer ring 1 becomes an ellipse after compression. The endpoint of the major axis of the ellipse is located at the thinnest part of the wall thickness of the flexible outer ring 1, and the endpoint of the minor axis is located at the thickest part of the wall thickness of the flexible outer ring 1. Correspondingly, the flexible inner ring 2 also becomes an ellipse under the action of the roller 4. The compressed flexible bearing is as follows Figure 6 As shown. When the flexible bearing is operating in an internal gear harmonic drive device, the input rotor 5 drives the flexible outer ring 1 to rotate together, causing the major and minor axes of the ellipse formed after the flexible inner ring 2 is compressed to continuously change, thereby causing the flexspline teeth 21 at different positions to mesh with the outer teeth 61 of the rigid wheel 6, thereby driving the rigid wheel 6 to rotate. During this process, the flexspline teeth 21 at the minor axis of the ellipse formed after the flexible inner ring 2 is compressed to mesh with the outer teeth 61 on the rigid wheel 6, while the flexspline teeth 21 at the major axis disengage from the outer teeth 61 on the rigid wheel 6, thereby improving the operating accuracy. In addition, the input rotor 5 and the flexible outer ring 1 remain relatively stationary (rotating synchronously), thereby avoiding the problem of fracture due to stress concentration at the thinner wall of the flexible outer ring 1.

[0046] In the above process, the elliptical deformation of the flexible inner ring 2 caused by the cooperation of the input rotor 5 with a circular inner wall and the flexible outer ring 1 with uneven wall thickness is used to directly drive the rotation of the internal rigid wheel 6. 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 internal tooth harmonic transmission device in the prior art, which must be composed of a rigid wheel, a flexible outer wheel, a flexible bearing and a wave generator, and changes the way in which the wave generator is required to drive the rigid wheel to rotate. It also solves the problem of the internal tooth harmonic transmission device in the prior art being difficult to assemble and the inability to ensure assembly accuracy. At the same time, the inner 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.

[0047] The internal gear 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 outer ring of the traditional flexible bearing has a uniform wall thickness, while this application designs the outer 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. While passively assuming the bearing function, it can actively generate mechanical waves.

[0048] The flexible inner ring 2 in the flexible bearing of this embodiment plays the role of the inner ring of the bearing and also plays the role of the flexible wheel in the prior art. The flexible outer ring 1 plays the role of the outer ring of the bearing and also plays the role of the wave generator in the prior art. Therefore, when the flexible bearing of this embodiment is used in the internal gear harmonic reduction device, there is no need to install the wave generator and the flexible wheel 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.

[0049] 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 internal gear harmonic transmission device, characterized in that: It includes a flexible outer ring and a flexible inner ring, 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 outer ring is unevenly set, the wall thickness of the flexible inner ring is uniformly set, the flexible inner ring is connected to the flexible spline teeth, the flexible outer ring is used to be sleeved inside the input rotor, the inner wall of the input rotor is circular to drive the flexible outer ring to deform; the outer wall of the flexible outer ring is elliptical, the inner wall of the flexible outer ring is circular, the outer wall of the flexible inner ring is circular, and the inner wall of the flexible inner ring is provided with the flexible spline teeth.

2. The flexible bearing according to claim 1, characterized in that: The flexspline teeth and the flexible inner 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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