Harmonic reducer

Abstract

The utility model relates to the technical field of speed reducers, in particular to a harmonic speed reducer which comprises an outer ring, an inner ring, a crossed roller bearing, an oil storage sealing piece, a rigid wheel installed on one side of the inner ring, a flexible wheel installed on the side, away from the steel wheel, of the outer ring, and a wave generator installed on the inner ring of the flexible wheel. One end of the flexible gear extends towards the rigid gear in the inner ring, and the outer teeth on the flexible gear are meshed with the inner teeth on the rigid gear; the wave generator is located on the inner side of the rigid wheel and comprises a cam and a flexible ball bearing, and the flexible ball bearing is made of ceramic materials. The utility model has the advantages of meeting the requirements of compactness, easiness in production and assembly and long service life at the same time.

Description

Technical Field

[0001] This application relates to the technical field of speed reducers, and particularly to a harmonic speed reducer. Background Technology

[0002] Harmonic reducers, as key components in the field of mechanical transmission, are widely used in robotics, aerospace, medical devices, and many other fields. They mainly consist of core components such as a flexspline, crossed roller bearings, a rigid wheel, and a wave generator. Among these, the wave generator plays a crucial role, being a combination of a cam and a flexible ball bearing. Through its unique structural design and motion mechanism, the wave generator cleverly and precisely converts the rotational motion of the input shaft into harmonic vibrations of the flexspline, thereby achieving efficient and precise speed reduction transmission.

[0003] In recent years, with the rapid development of technology, the application scenarios of harmonic reducers have been continuously expanding and deepening. In emerging application fields such as miniaturized robots and precision medical devices, more stringent requirements have been placed on the compactness of harmonic reducers. At the same time, to ensure the long-term stable operation of equipment, expectations for their service life are also increasing.

[0004] Research has revealed that the lifespan of harmonic reducers largely depends on key components such as flexible ball bearings, crossed roller bearings, and flexsplines. Traditional harmonic reducers struggle to simultaneously meet the dual requirements of compactness and long lifespan in the design and material selection of these components. For example, pursuing a longer lifespan might involve using larger bearings, which undoubtedly increases the overall size and weight, failing to meet compactness requirements. Conversely, solely pursuing a compact design might require compromises in materials or structure, thereby affecting the lifespan of the harmonic reducer or increasing the difficulty of its manufacturing and assembly. This contradiction limits the application and development of harmonic reducers in many scenarios where both compactness and long lifespan are critical. Utility Model Content

[0005] To meet the requirements of compactness, ease of production and assembly, and long service life, this application provides a harmonic reducer.

[0006] This application provides a harmonic reducer, which adopts the following technical solution:

[0007] A harmonic reducer includes an outer ring, an inner ring, a crossed roller bearing and an oil reservoir seal disposed between the outer ring and the inner ring, a rigid wheel mounted on one side of the inner ring, a flexible wheel mounted on the side of the outer ring away from the rigid wheel, and a wave generator mounted on the inner ring of the flexible wheel. One end of the flexible wheel extends into the inner ring towards the rigid wheel, and the external teeth on the flexible wheel mesh with the internal teeth on the rigid wheel. The wave generator is located inside the rigid wheel and includes a cam and a flexible ball bearing made of ceramic material.

[0008] By adopting the above technical solution, the overall structure is compact, and the use of a split design for the inner ring and rigid wheel reduces the difficulty of processing. The design of the oil reservoir seal can store oil, improve the lubrication cycle of the crossed roller bearing, and increase the service life of the crossed roller bearing. The lifespan of flexible ball bearings primarily depends on lubrication. However, flexible ball bearings operate at high speeds, generating heat that can easily cause lubricating oil to leak out. Therefore, by using ceramic materials, several advantages are achieved. First, ceramic bearings have a low coefficient of friction, meaning that even with thinned or insufficient grease, their lubrication capacity remains comparable to that of steel bearings using traditional lubricants. Second, ceramic bearings have a long service life due to the lower heat generated by friction, especially at high speeds, which helps extend the lifespan and lubrication cycle of the wave generator. Third, the manufacturing process of ceramic bearings utilizes precision machining equipment and techniques, resulting in high accuracy. Furthermore, the low coefficient of thermal expansion of ceramic materials allows wave generators equipped with ceramic bearings to maintain good accuracy even at high temperatures. Fourth, ceramic bearings are lighter than steel ball bearings, resulting in a smaller moment of inertia in wave generators equipped with ceramic bearings, which helps improve the transmission accuracy of the reducer. Fifth, the elastic modulus of ceramics is higher than that of steel, increasing the rigidity of the reducer, improving its stiffness and response speed, and reducing errors.

[0009] In one embodiment, the rollers of the flexible ball bearing are made of Si3N4.

[0010] By adopting the above technical solution, Si3N4 has the advantages of high strength, lightweight properties and environmental resistance, which can further improve the service life of roller balls.

[0011] In one embodiment: a sealing cavity for installing an oil reservoir seal is provided between the outer ring and the inner ring on the side where the rigid wheel is located, and the sealing cavity is connected to the mounting cavity of the crossed roller bearing.

[0012] By adopting the above technical solution, an oil storage seal is installed through a sealed cavity, and oil replenishment of the crossed roller bearing is achieved by communicating with the installation cavity.

[0013] In one embodiment: the oil storage seal includes a body and a deformable part, the body is C-shaped, the deformable part closes the C-shaped opening of the body, and a deformable cavity is formed between the deformable part and the body.

[0014] By adopting the above technical solution, the C-shaped main body and the deformation part set at the C-shaped opening position are configured so that when lubricating oil enters the sealing cavity, it can push the deformation part to deform into the C-shaped opening of the main body, thereby forming an oil reservoir. When the lubricating oil in the crossed roller bearing decreases, the restoring force of the deformation part can replenish the lubricating oil in the sealing cavity into the crossed roller bearing.

[0015] In one embodiment, the deformable part is configured as an arc-shaped structure protruding outward from the C-shaped opening of the main body.

[0016] By adopting the above technical solution, the deformation of the deformed part can be increased, thereby increasing the oil storage capacity.

[0017] In one embodiment: the main body includes a sealing part and a skeleton, the sealing part includes an outer sealing part that abuts against an outer ring and an inner sealing part that abuts against an inner ring, the outer sealing part and the inner sealing part are disconnected, and the skeleton is embedded outside the sealing part and maintains the abutment between the outer sealing part and the inner sealing part.

[0018] By adopting the above technical solution, the disconnected outer and inner sealing parts are set, which facilitates the production of oil storage seals. The skeleton setting can support the sealing part on the one hand, and prevent the disconnected positions of the outer and inner sealing parts from being misaligned during use, which would lead to seal failure.

[0019] In one embodiment: the inner sealing portion extends obliquely downward toward the cross roller bearing direction with a sealing lip, one end of the deformable portion is connected to the sealing lip, and the end of the sealing lip extends out of the deformable portion.

[0020] By adopting the above technical solution, the sealing lip not only achieves a seal with the inner ring, but also guides the lubricating oil so that it can better act on the deformed part.

[0021] In one embodiment, a spring is fitted onto the sealing lip.

[0022] By adopting the above technical solution, a force is applied to the sealing lip towards the inner ring by a spring, which prevents the sealing lip from lifting and failing during the deformation process of the deformable part.

[0023] In one embodiment, the outer circumference of the rigid wheel is provided with abutting protrusions for abutting against the oil storage seal.

[0024] By adopting the above technical solution, the anti-protrusion can limit the oil storage seal and prevent it from falling out of the sealing cavity.

[0025] In one embodiment: the abutting protrusion at least partially abuts against the skeleton.

[0026] By adopting the above technical solution, the oil storage seal can be better constrained by the skeleton. Attached Figure Description

[0027] Figure 1 This is a structural schematic diagram of this embodiment;

[0028] Figure 2This is a partial structural diagram of this embodiment, showing the state of the deformed part after deformation.

[0029] In the diagram, 100 is the outer ring; 200 is the inner ring; 300 is the crossed roller bearing; 400 is the oil reservoir seal; 410 is the main body; 411 is the skeleton; 412 is the sealing part; 4121 is the outer sealing part; 4122 is the inner sealing part; 4123 is the sealing lip; 4124 is the spring; 420 is the deformation part; 500 is the rigid wheel; 510 is the internal gear; 520 is the abutment protrusion; 600 is the flexible wheel; 610 is the external gear; 620 is the oil reservoir gap; 630 is the oil reservoir cavity; 700 is the wave generator; 710 is the cam; and 720 is the flexible ball bearing. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the accompanying drawings.

[0031] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0032] A type of harmonic reducer, such as Figure 1 As shown, it includes an outer ring 100, an inner ring 200, a crossed roller bearing 300 and an oil reservoir seal 400 disposed between the outer ring 100 and the inner ring 200, a rigid wheel 500 mounted on one side of the inner ring 200, a flexible wheel 600 mounted on the side of the outer ring 100 away from the rigid wheel, and a wave generator 700 mounted on the inner ring 200 of the flexible wheel 600. One end of the flexible wheel 600 extends into the inner ring 200 toward the rigid wheel 500, and the external teeth 610 on the flexible wheel 600 mesh with the internal teeth 510 on the rigid wheel 500.

[0033] The flexible wheel 600 and the outer ring 100, and the rigid wheel 500 and the inner ring 200, are all fixedly connected by bolts. Additionally, sealing rings are provided between the flexible wheel 600 and the outer ring 100, and between the rigid wheel 500 and the inner ring 200. An oil reservoir gap 620 is formed between the outer ring 100, the inner ring 200, the rigid wheel 500, and the flexible wheel 600. Furthermore, the inner ring 200 is recessed on its inner side facing the end where the steel wheel is located, and this recessed design allows the oil reservoir gap 620 to be located at the end where the rigid wheel 500 is located, forming an oil reservoir cavity 630. The oil reservoir cavity 630 allows for the storage of more lubricating oil, and its proximity to the internal gear 510 and the external gear 610 makes it easier to supply lubricating oil to them.

[0034] The wave generator 700 is located inside the rigid wheel 500. The wave generator 700 includes a cam 710 and a flexible ball bearing 720. The flexible ball bearing 720 is made of ceramic material, and the roller ball material of the flexible ball bearing 720 is Si3N4.

[0035] like Figure 2 As shown, a sealing cavity for installing the oil reservoir seal 400 is provided between the outer ring 100 and the inner ring 200 on the side where the rigid wheel 500 is located. The sealing cavity communicates with the mounting cavity of the crossed roller bearing 300. The side wall of the sealing cavity near the side where the crossed roller bearing 300 is located is inclined, and the communication channel between the sealing cavity and the mounting cavity of the crossed roller bearing 300 is located at the bottom of the inclination. The inclination forms a guide, facilitating the delivery of lubricating oil into the mounting cavity of the crossed roller bearing 300. The oil reservoir seal 400 is installed through the sealing cavity, and the oil supply to the crossed roller bearing 300 is achieved through the communication with the mounting cavity.

[0036] The oil reservoir seal 400 includes a main body 410 and a deformable portion 420. The main body 410 has a C-shaped structure, and the deformable portion 420 closes the C-shaped opening of the main body 410, forming a deformable cavity between the deformable portion 420 and the main body 410. The deformable portion 420 is configured with an arc-shaped structure protruding outward from the C-shaped opening of the main body 410. When the seal is filled with lubricating oil, pressure can push the deformable portion 420 to deform and form the seal. Figure 2 The concave state shown in the figure allows for the replenishment of lubricating oil in the crossed roller bearing 300 during lubrication loss, thanks to the restoring force of the deformation part 420.

[0037] The main body 410 includes a sealing part 412 and a frame 411. The sealing part 412 includes an outer sealing part 4121 that abuts against the outer ring 100 and an inner sealing part 4122 that abuts against the inner ring 200. The outer sealing part 4121 and the inner sealing part 4122 are disconnected. The frame 411 is embedded outside the sealing part 412 and maintains the abutment between the outer sealing part 4121 and the inner sealing part 4122.

[0038] The inner sealing portion 4122 extends obliquely downward toward the crossed roller bearing 300 with a sealing lip 4123. One end of the deformable portion 420 is connected to the sealing lip 4123, and the end of the sealing lip 4123 extends out of the deformable portion 420. The sealing lip 4123 serves two purposes: firstly, it achieves a seal with the inner ring 200, and secondly, it guides the lubricating oil, allowing it to act more effectively on the deformable portion 420.

[0039] A spring 4124 is fitted on the sealing lip 4123. The spring 4124 applies a force toward the inner ring 200 to the sealing lip 4123 to prevent the sealing lip 4123 from lifting up and failing during the deformation of the deformable part 420.

[0040] Furthermore, the outer circumference of the rigid wheel 500 is provided with an abutment protrusion 520 for abutting against the oil reservoir seal 400, and the abutment protrusion 520 at least partially abuts against the frame 411. The abutment protrusion 520 can limit the oil reservoir seal 400 and prevent it from falling out of the seal, and the abutment against the frame 411 can better limit the oil reservoir seal 400.

[0041] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A harmonic reducer characterized by: The application relates to a cross-roller bearing, which comprises an outer ring (100), an inner ring (200), a cross-roller bearing (300) arranged between the outer ring (100) and the inner ring (200), an oil storage sealing element (400), a rigid gear (500) arranged on one side of the inner ring (200), a flexible gear (600) arranged on the side of the outer ring (100) away from the rigid gear (500), and a wave generator (700) arranged in the inner ring (200) of the flexible gear (600), wherein one end of the flexible gear (600) extends into the inner ring (200) and towards the rigid gear (500), and the external teeth (610) of the flexible gear (600) are engaged with the internal teeth (510) of the rigid gear (500); the wave generator (700) is arranged on the inner side of the rigid gear (500), and the wave generator (700) comprises a cam (710) and a flexible ball bearing (720), wherein the flexible ball bearing (720) is made of ceramic material.

2. The harmonic reducer of claim 1, wherein: The material of the roller ball of the flexible ball bearing (720) is Si3N4.

3. The harmonic reducer of claim 1, wherein: A sealing cavity for mounting the oil storage sealing element (400) is arranged on the side of the outer ring (100) and the inner ring (200) where the rigid gear (500) is arranged, and the sealing cavity is communicated with the mounting cavity of the cross-roller bearing (300).

4. The harmonic reducer of claim 2, wherein: The oil storage sealing element (400) comprises a main body (410) and a deformation part (420), the main body (410) is in C shape, the deformation part (420) closes the C-shaped opening of the main body (410), and a deformation cavity is formed between the deformation part (420) and the main body (410).

5. The harmonic reducer of claim 4, wherein: The deformation part (420) is arranged in arc shape protruding outwardly towards the C-shaped opening of the main body (410).

6. The harmonic reducer of claim 5, wherein: The main body (410) comprises a sealing part (412) and a framework (411), the sealing part (412) comprises an outer sealing part (4121) abutting against the outer ring (100) and an inner sealing part (4122) abutting against the inner ring (200), the outer sealing part (4121) and the inner sealing part (4122) are arranged in discontinuous mode, and the framework (411) is embedded outside the sealing part (412) and keeps the outer sealing part (4121) and the inner sealing part (4122) abutting.

7. The harmonic reducer of claim 6, characterized by: The inner sealing part (4122) extends downwardly and obliquely towards the cross-roller bearing (300) and is provided with a sealing lip (4123), one end of the deformation part (420) is connected to the sealing lip (4123), and the end of the sealing lip (4123) extends outwardly from the deformation part (420).

8. The harmonic reducer of claim 7, characterized by: The sealing lip (4123) is sleeved with a spring (4124).

9. The harmonic reducer of claim 6, wherein: The outer circle of the rigid gear (500) is provided with an abutting protrusion (520) for abutting against the oil storage sealing element (400).

10. The harmonic reducer of claim 9, characterized by: The abutting protrusion (520) is at least partially abutted against the framework (411).

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