Swing type harmonic reducer

Abstract

The embodiment of the invention discloses a swing type harmonic reducer. The swing type harmonic reducer comprises a cylindrical shell, a rigid wheel, a balance wheel and a harmonic generator. The rigid gear is rotationally installed in the cylindrical shell, the gear face, facing the interior of the cylindrical shell, of the rigid gear is a conical face, auxiliary gear teeth are arranged on the conical face of the rigid gear, a ball groove is formed in the center of the gear face, close to the auxiliary gear teeth, of the rigid gear, and the gear face, away from the ball groove, of the rigid gear is connected with an output shaft. The balance wheel is arranged in the cylindrical shell, the wheel face, facing the rigid wheel, of the balance wheel is provided with main wheel teeth, the difference between the tooth number of the main wheel teeth and the tooth number of the auxiliary wheel teeth is one, the center of the end face, close to the main wheel teeth, of the balance wheel is fixedly provided with a ball joint, the ball joint is matched with the ball groove in a rotating and swinging mode, and the side, away from the ball joint, of the balance wheel is provided with a swinging receiving face. And the swing receiving surface is integrally connected with the balance wheel. By adopting the arrangement, the embodiment of the invention has the advantages of high rigidity, strong loading capacity, high back clearance precision, long service life and simple structure.

Description

Technical Field

[0001] The present application belongs to the technical field of high-precision reducer structure and high-precision dividing plate structure, and specifically relates to a swing-type harmonic reducer. Background Art

[0002] There are two main types of robot joint reducers currently used in the market: RV reducers (such as Figure 1 as shown) and harmonic reducer (as Figure 2 shown).

[0003] The existing RV reducer consists of a planetary gear reducer front stage and a cycloid pinwheel reducer rear stage. The RV reducer has a compact structure, a large transmission ratio, and a transmission mechanism with a self-locking function under certain conditions. It is one of the most commonly used reducers and has low vibration, low noise, and low energy consumption. The RV reducer has the following disadvantages:

[0004] ① Large backlash and poor precision. The backlash is generally around 1 arc minute. The main reasons for the backlash in the RV reducer are the cycloid tooth profile error, the needle roller and needle roller tooth profile error, the cycloid wheel eccentricity error and other errors. Various errors can be directly converted into a tooth profile error equivalent to the needle roller. Due to the many error factors, and the error amplification effect of the cycloid wheel tooth profile and eccentric structure, the backlash is large. See Figure 3 In contrast, the harmonic reducer structure has almost no error amplification effect. Therefore, even the pure high-precision cycloid reducer on the market is basically around 1 arc minute, which is difficult to reduce further. ② The eccentric bearing is subjected to large force: see Figure 3 Tooth profile error comparison and force analysis: providing the same size of circumferential force T, the cycloid needle requires a larger inter-tooth pressure N, resulting in a larger radial force R of the cycloid wheel, which in turn causes a large force on the eccentric bearing. A large load-bearing bearing must be selected, otherwise the service life will be reduced.

[0005] The existing harmonic gear reducer is a kind of reduction device, which consists of three basic components: a fixed internal gear wheel, a flexible wheel (i.e., an elastic thin-walled sleeve cup whose base is connected to the output shaft "making a gear ring on the generatrix at the beginning of the flexible wheel"), and a wave generator that causes radial deformation of the flexible wheel. Harmonic gear reducers have the following disadvantages:

[0006] ① Low stiffness (generally about 20-30% of RV reducer) and poor load capacity, especially when the load is large, the accuracy and life will decrease rapidly (the life of harmonic reducer is usually about 10-30% of RV reducer). Figure 2It can be seen that the main reason is that the purpose of tooth meshing and withdrawal can only be achieved by relying on the deformation of the flexwheel cylinder (the deformation is generated by the ellipse of the harmonic generator), but the gear teeth are located on a thin-walled flexwheel cylinder. The thin and long wall of the flexwheel cylinder leads to poor torsional stiffness, especially when the load is large. The flexwheel cylinder at the base of the gear teeth has been deformed, and the gear teeth are in a non-ideal meshing state, which leads to rapid wear. Some manufacturers make the wall of the flexwheel cylinder thicker and shorter in order to improve torsional stiffness, but it will increase the starting torque (the force that causes the deformation of the flexwheel cylinder will increase), and the elastic deformation stress of the flexwheel cylinder will also increase, resulting in premature fatigue fracture of the flexwheel cylinder and fatigue damage of the harmonic generator bearing. ② Another reason for low life: Due to the sliding between the gear teeth, the pressure angle is large, which leads to wear and reduces the life.

[0007] From this, it can be seen that the existing harmonic gear reducers mainly have the following problems: 1. Insufficient rigidity; 2. Weak load capacity; 3. Small backlash and high precision; 4. Short service life; 5. Simple structure; while the RV reducer mainly has the following problems: 1. High rigidity; 2. Strong load capacity; 3. Large backlash and low precision; 4. Long service life; 5. Complex structure; The advantages and disadvantages of the two are exactly opposite, so there is a need for an improved space that has the advantages of both. Summary of the invention

[0008] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a swing-type harmonic reducer having the advantages of high rigidity, strong load capacity, high backlash accuracy, long service life and simple structure.

[0009] The purpose of this application is achieved through the following technical solutions:

[0010] The present application proposes an oscillating harmonic reducer, comprising a cylindrical shell, a rigid wheel, a balance wheel, and a harmonic generator; the rigid wheel is rotatably installed in the cylindrical shell, the wheel surface of the rigid wheel facing the cylindrical shell is a conical surface, the conical surface of the rigid wheel is provided with secondary gear teeth, a ball groove is provided at the center of the wheel surface of the rigid wheel close to the secondary gear teeth, and the wheel surface of the rigid wheel away from the ball groove is integrally connected with an output shaft; the balance wheel is arranged in the cylindrical shell, the wheel surface of the balance wheel facing the rigid wheel is provided with main gear teeth, the number of teeth of the main gear teeth differs from the number of teeth of the secondary gear teeth by 1, and a ball joint is fixedly provided at the center of the end surface of the balance wheel close to the main gear teeth The ball joint and the ball groove are fixed with the ball center and rotate and swing together. A swing receiving surface is arranged on the side of the balance wheel away from the ball joint. A groove is arranged on the swing receiving surface. The groove of the swing receiving surface is connected with the balance wheel as a whole. The harmonic generator has a swing driving inclined surface. The swing receiving surface and the swing driving inclined surface are contact-coupled through rolling bodies in the groove. The rotation of the input shaft drives the swing driving inclined surface to rotate. Driven by the swing driving inclined surface, the balance wheel swings periodically in a wave shape along a ring about the ball joint, so that the main gear teeth of the balance wheel gradually mesh with the secondary gear teeth of the rigid wheel, thereby driving the rigid wheel and the output shaft to rotate.

[0011] Furthermore, the inner circumferential surface of the cylindrical shell is provided with a plurality of long arc grooves, which are evenly spaced along the circumferential direction and extend along the length direction of the cylindrical shell; the outer circumferential surface of the balance wheel is provided with a plurality of arc grooves, which are evenly spaced along the circumferential direction; the arc grooves of the balance wheel are the same in number and correspond to the long arc grooves of the cylindrical shell, the arc direction of the arc grooves is consistent with the arc direction of the long arc grooves, and a plurality of first rolling bodies are arranged in the arc grooves and the long arc grooves, and the first rolling bodies abut against the inner walls of the relative arc grooves and the long arc grooves.

[0012] Furthermore, the swing driving inclined surface is integrally connected to an input shaft, the input shaft and the cylindrical shell remain relatively concentric and only rotate, the input shaft drives the swing driving inclined surface to rotate as a driving source, the swing driving inclined surface has a swing angle deviation relative to the center of the ball groove when rotating, the swing driving inclined surface is provided with an annular groove, the annular groove and the swing receiving surface of the balance wheel are contact-coupled through rolling bodies, the input shaft drives the swing driving inclined surface to rotate, and the deviation angle generated about the ball joint during rotation drives the balance wheel to swing.

[0013] Furthermore, the end surface of the balance wheel facing the rigid wheel is a large-angle conical surface or can even be a flat surface.

[0014] Furthermore, the tooth profile of the main gear of the balance wheel is a double elliptical curve tooth profile to ensure 100% full tooth engagement between the teeth.

[0015] Furthermore, the ball center of the ball joint, the cone top of the balance wheel, the cone top of the rigid wheel, and the eccentricity of the swing driving inclined surface of the harmonic generator during operation are all concentrically arranged.

[0016] Furthermore, the inner wall of the ball groove is coupled to the outer peripheral surface of the ball joint directly or through a rolling body.

[0017] Furthermore, the rigid wheel and the balance wheel are both made of rigid materials.

[0018] Furthermore, an oil seal is provided in the gap between the outer peripheral surface of the rigid wheel and the inner wall of the cylindrical shell.

[0019] This application has the following beneficial effects:

[0020] 1) The speed reduction is achieved between the balance wheel and the rigid wheel through the swing of the balance wheel. The force is transmitted between the balance wheel and the rigid wheel through nearly 100% inter-tooth meshing. The balance wheel transmits the force to the cylindrical housing through the rolling body in the radial groove, and the balance wheel outputs the force through the gear teeth through the rigid wheel output shaft. In this way, the force transmission path is a rigid body, so that the reducer has high force transmission rigidity and strong load carrying capacity. Nearly 100% of the multi-teeth are meshed at the same time, which is nearly 3 times the number of teeth meshed at the same time in the harmonic reducer, and the force transmission capacity of the teeth is also high.

[0021] 2) The balance wheel and the rigid wheel of the present application adopt a large-angle bevel gear structure, and both the main wheel teeth and the secondary wheel teeth adopt a double elliptical curve tooth shape. Therefore, the perfect match of the large-angle bevel gear and the double elliptical curve tooth shape can fully achieve 100% meshing. Nearly 100% inter-tooth meshing can not only improve the high rigidity of force transmission, but also have strong load-bearing capacity; nearly 100% multi-teeth meshing at the same time is nearly 3 times the number of teeth meshing at the same time of the harmonic reducer. According to the error averaging principle, the backlash accuracy will be slightly higher than that of the harmonic reducer. Due to the concentric structure of the teeth of the balance wheel and the rigid wheel, the tooth shape error is directly reflected in the backlash error, so the backlash accuracy is high.

[0022] 3) The balance wheel of the present application adopts a ball joint that is concentric with the ball groove of the rigid wheel and is connected by swinging and rotating. This co-centric (also cone-tip) coupling method can, on the one hand, eliminate radial wear of the tooth profile, and on the other hand, the wear of the ball joint is in the same direction as the wear of the tooth, which is conducive to debugging and reuse after wear.

[0023] 4) When the input shaft of the harmonic reducer rotates one circle, the gear teeth are pushed in and out at least twice, while this reducer only has one time, which reduces the number of wear times by half, thus reducing wear. In addition, the pressure angle of the harmonic reducer tooth profile is generally around 20°, while this application requires the pressure angle to be less than 10°. The same force is transmitted, which will result in reduced friction between teeth, reduce wear, and increase life. Nearly 100% of the teeth are engaged simultaneously, which is nearly 3 times the number of teeth engaged simultaneously in the harmonic reducer. The force converted to a single tooth will also be reduced to 1 / 3, thereby reducing wear and increasing life.

[0024] 5) An integrated simple overall force transmission structure: that is, the swing-type harmonic reducer of the present application includes a simple harmonic generation method, a radial spherical constant velocity coupling force transmission method of the balance wheel (when the balance wheel is used as the output, the constant velocity meaning of this coupling is used), a conical center (also the cone tip) positioning method of the harmonic reduction mechanism, a conical reduction structure, etc., which condenses multiple functional requirements into such simple parts (rigid wheel, balance wheel, cylindrical housing, harmonic generator), and the simple structure is convenient for reducing costs and mass production.

[0025] 6) Small starting torque: There is no need to overcome the elastic deformation of the flexible wheel cylinder of the commonly used harmonic reducer, so the starting torque is small.

[0026] 7) Compared with the existing RV reducer and harmonic gear reducer, the RV reducer has the advantages of excellent rigidity, strong load capacity and long service life; it also has the advantages of high backlash accuracy and simple structure of the harmonic reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the RV reducer principle of the prior art.

[0028] Figure 2 The figure is a schematic diagram of the principle of a harmonic reducer in the prior art.

[0029] Figure 3 Schematic diagram of tooth profile error comparison and force analysis.

[0030] Figure 4 This is a principle analysis diagram of the RV reducer (cycloidal reducer) and the harmonic reducer in the prior art.

[0031] Figure 5 For Figure 4 The inner ring tooth height transformation principle diagram of the cycloid needle reducer and harmonic reducer analyzed and the improved swing harmonic reduction principle diagram.

[0032] Figure 6 This is a schematic diagram of the principle of the swing harmonic reducer of this application.

[0033] Figure 7 Based on Figure 6 Schematic diagram of the appearance structure of the swing type harmonic reducer.

[0034] Figure 8 for Figure 7 sectional view of .

[0035] Fig. 9 for Figure 8 A partial enlarged view of point A in the middle.

[0036] Fig.10 for Figure 7 Exploded cross-sectional view.

[0037] In the figure:

[0038] 1. Cylindrical housing; 11. Front cylinder; 111. Rounded corner groove; 12. Middle cylinder; 121. Long arc groove; 13. Rear cylinder; 131. Circular arc groove; 14. Oil seal;

[0039] 2. rigid wheel; 21. ball groove; 22. auxiliary gear teeth; 23. output shaft; 24. annular step groove;

[0040] 3. Balance wheel; 31. Ball joint; 32. Main wheel teeth; 33. Arc groove; 34. Groove;

[0041] 4. harmonic swing generator; 41. input shaft; 42. driving pressure plate; 421. swing driving inclined surface; 422. bearing convex ring; 423. annular groove; 43. input connecting groove shaft hole;

[0042] 5. The first rolling body; 6. The second rolling body; 7. The third rolling body; 8. The fourth rolling body; 9. The fifth rolling body. DETAILED DESCRIPTION

[0043] The present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The terms such as "upper", "inner", "middle", "left", "right" and "one" cited in this specification are only for the convenience of description, and are not used to limit the scope of implementation of the present application. The change or adjustment of their relative relationship shall also be regarded as the scope of implementation of the present application without substantially changing the technical content.

[0044] This application aims at the main problems of harmonic gear reducers in the prior art: 1. Insufficient rigidity; 2. Weak load capacity; 3. Small backlash and high precision; 4. Short service life; 5. Simple structure; The main problems of RV reducers: 1. High rigidity; 2. Strong load capacity; 3. Large backlash and low precision; 4. Long service life; 5. Complex structure; Therefore, a swing-type harmonic reducer is designed. The idea and principle of this reducer: whether it is a cycloidal needle reducer or a harmonic reducer, the rigid outer ring is sleeved with a moving inner ring. The one with only one contact is a single-wave harmonic reducer. The inner ring is rigid and can only achieve contact by eccentricity, which is called an eccentric reducer with small tooth difference. In order to reduce the wear between teeth, the tooth shape is changed to cylindrical and cycloidal, which is a cycloidal reducer. The one with two-point contact is a double-wave harmonic reducer. In order to achieve two-point contact, the inner ring adopts elastic deformation, which is commonly known as a harmonic reducer. This harmonic deceleration method has an implicit problem: ① The difference in the diameter of the inner and outer rings must be greater than at least one tooth height to achieve the gap between teeth, so the difference in the number of teeth is generally 2 to 6, or even more. If the number of teeth differs too much, the reduction ratio will be small, and the purpose of a large reduction ratio cannot be achieved. ② Reducing the tooth height to achieve the gap between teeth can achieve a large reduction ratio with a relatively small difference in the number of teeth, but too small a tooth height will lead to discontinuous meshing transmission.

[0045] First of all, the application must ensure that the inner ring is rigid and does not deform, in order to eliminate the disadvantage of low force transmission stiffness caused by the thin wall of the inner ring of harmonic deceleration. Secondly, in order to achieve a large reduction ratio, the minimum difference in the number of teeth is selected to be 1 tooth. This results in the difference in the diameter of the inner and outer rings being less than the tooth height, causing interference and unable to achieve the crossover between teeth. Figure 4 and Figure 5 As shown, in order to reduce the tooth height and achieve continuity of meshing, the inner and outer circles of the cylinder are converted into inner and outer cones with the same cone tip. The cylinder can be regarded as a cone with the cone tip infinitely far away; the tooth height on the cylinder converted into the tooth height in the direction perpendicular to the cone surface is the cosine relationship of the cone angle, so the larger the cone angle, the smaller the tooth height.

[0046] The following is a detailed introduction to the structure of the swing type harmonic reducer of the present application:

[0047] This embodiment proposes a swing type harmonic reducer, such as Figures 6 to 10As shown, it includes a cylindrical housing 1, a rigid wheel 2, a balance wheel 3, and a harmonic swing generator 4. The rigid wheel 2 is rotatably mounted in the cylindrical housing 1, and the wheel surface of the rigid wheel 2 facing the cylindrical housing 1 is a conical surface. The conical surface of the rigid wheel 2 is provided with secondary gear teeth 22, and the secondary gear teeth 22 are distributed along the circumferential direction. A ball groove 21 is provided at the center of the wheel surface of the rigid wheel 2 close to the secondary gear teeth 22, and the wheel surface of the rigid wheel 2 away from the ball groove 21 is connected to an output shaft 23. The balance wheel 3 is arranged in the cylindrical housing 1, and the wheel surface of the balance wheel 3 facing the rigid wheel 2 is provided with main gear teeth 32, and the number of the main gear teeth 32 differs from the number of the secondary gear teeth 22 by 1 tooth. A ball joint 31 is fixedly arranged at the center of the end surface of the balance wheel 3 close to the main gear teeth 32, and the ball joint 31 is matched with the ball groove 21 for rotation and swinging, and the end surface of the balance wheel 3 away from the ball joint 31 has a swing receiving surface.

[0048] The harmonic generator has a swing driving inclined plane, which is only rotatably mounted in the cylindrical housing. The swing driving inclined plane is located on the side of the balance wheel away from the rigid wheel. The swing driving inclined plane faces the swing receiving surface of the balance wheel, which drives the balance wheel to swing due to the rotation of the inclined plane. The swing driving inclined plane has a swing angle relative to the ball center of the ball groove. The swing driving inclined plane is offset from the receiving surface of the balance wheel. Driven by the swing driving inclined plane, the balance wheel 3 swings periodically along the annular wave shape about the ball joint 31, so that the main gear teeth 32 of the balance wheel 3 gradually mesh with the secondary gear teeth 22 of the rigid wheel 2, thereby driving the rigid wheel 2 and the output shaft 23 to decelerate.

[0049] Based on the above settings, the deceleration principle of the swing harmonic reducer is as follows:

[0050] Comparing the present application with the cycloidal needle reducer principle and the harmonic accelerator principle of the prior art, the swing harmonic reducer of the present application is the same as the harmonic reducer (cycloidal needle reducer), the balance wheel 3 (equivalent to the flexible wheel or cycloidal wheel of the existing harmonic reducer) and the rigid wheel 2 (equivalent to the rigid wheel 2 or needle wheel of the existing harmonic reducer) have the same spherical center (also called the cone tip), and the balance wheel 3 only swings but does not rotate under the driving action of the harmonic generator, and the rigid wheel 2 only rotates along the coaxial line. The periodic oscillation of the balance wheel 3 along the circumferential direction is also called harmonic motion. The torque is transmitted between the balance wheel 3 and the rigid wheel 2 through the meshing of the main gear teeth 32 and the secondary gear teeth 22. The harmonic motion causes the balance wheel 3 to gradually go in and out, wherein the secondary gear teeth 22 and the main gear teeth 32 both adopt a double elliptical tooth shape, which can perfectly ensure that all the gear teeth participate in the meshing. Since the balance wheel 3 has one more or less gear tooth than the rigid wheel 2, the balance wheel 3 meshes in sequence along the circumferential direction (i.e., the gear teeth insert and withdraw). After one week, the rigid wheel 2 rotates more or less by an angle of one tooth relative to the balance wheel 3 (i.e., the output is opposite to the input), and the balance wheel 3 only swings but does not rotate. The output of the angle of one tooth that the rigid wheel 2 rotates more or less is the output speed after deceleration, which achieves the purpose of deceleration. The deceleration ratio depends on the number of teeth of the rigid wheel 2 or the balance wheel 3.

[0051] The deceleration part of the swing-type harmonic reducer of the present application is completely different from the common harmonic reducer and cycloid needle reducer structure. The main differences are: ① It is a conical gear meshing structure; ② It is a double elliptical tooth shape that matches the conical structure and can achieve 100% full tooth meshing; ③ The pressure angle of the double elliptical tooth shape is less than 10°; ④ The harmonics generated by the harmonic generator are swinging; ⑤ There is a constant velocity coupling structure between the balance wheel and the cylindrical shell; ⑥ The teeth are meshed, and the constant velocity coupling and the harmonic generator are mainly based on the ball center of the ball joint. Common harmonic deceleration is that the inner and outer cylindrical structures are matched with involute or cycloid needle or double arc tooth shapes. The outer ring does not rotate, but the inner ring rotates. The present application adopts an inner and outer cone structure (that is, the balance wheel 3 and the rigid wheel 2 structure) with a double elliptical tooth shape matching structure of the main gear teeth 32 and the secondary gear teeth 22 (such as Figure 3 The force analysis shows that the balance wheel 3 is both a moving wheel and a fixed wheel that does not rotate, while the rigid wheel 2 is stationary and only rotates the output wheel. The difference compared with the harmonic reducer is that the moving circle of the harmonic reducer is a flexible wheel, an elastic thin-walled cylinder, and the double-wave action is radial deformation. The moving tooth of the present application is the balance wheel 3, which is a solid body and the action is a single-wave swing.

[0052] In this embodiment, the cylindrical shell 1 includes a front cylinder 11, a middle cylinder 12 and a rear cylinder 13 which are connected by bolts and screws. The middle cylinder 12 is located between the front cylinder 11 and the rear cylinder 13. The inner diameters of the front cylinder 11 and the rear cylinder 13 are both larger than the inner diameter of the middle cylinder 12. The rigid wheel 2 is rotatably installed on the inner circumference of the front cylinder 11. A rounded groove 111 is provided on the edge of the inner circumference of the front cylinder 11 near the middle cylinder 12. An annular step groove 24 is provided on the outer circumference of the rigid wheel 2. The annular step groove 24 corresponds to the rounded groove 111. A plurality of fourth rolling bodies 8 are arranged between the annular step groove 24 and the rounded groove 111. The plurality of fourth rolling bodies 8 are formed into an integrated ring shape by a steel frame. The fourth rolling bodies 8 are abutted against the inner walls of the annular step groove 24 and the rounded groove 111 to realize the function of rotationally connecting the rigid wheel 2 and the front cylinder 11.

[0053] In this embodiment, in order to make the balance wheel 3 perform stable swinging motion under the driving action of the harmonic swing generator 4; the inner circumference of the middle cylinder 12 is provided with a plurality of long arc grooves 121, which are evenly spaced along the circumferential direction of the middle cylinder 12, and the number of the long arc grooves 121 is equal to the number of the arc grooves 33 of the balance wheel, and the long arc grooves 121 extend along the length direction of the middle cylinder 12, and the arc center of the long arc groove 121 faces the inside of the middle cylinder 12; the outer circumference of the balance wheel 3 is provided with a plurality of arc grooves 33, which are evenly spaced along the circumferential direction, and the number of the arc grooves 33 is the same as and corresponds to the long arc grooves 121, and the arc direction of the arc groove 33 is consistent with the arc direction of the long arc groove 121; a plurality of first rolling bodies 5 are arranged between the arc grooves 33 and the long arc grooves 121, and the first rolling bodies 5 are against the inner walls of the opposite arc grooves 33 and the long arc groove 121, so as to improve the stability of the swinging drive and reduce the friction during the swinging motion. At the same time, all the first rolling elements 5 between the inner circumference of the middle cylinder 12 and the outer circumference of the balance wheel 3 are framed into an integrated structure by a steel frame to maintain the integrity of all the first rolling elements 5 .

[0054] like Figures 6 to 10 As shown, the harmonic swing generator 4 includes an input shaft 41 and a driving plate 42. The input shaft 41 can be driven to rotate by a motor. The driving plate 42 is rotatably installed in the rear cylinder 13 of the cylindrical shell 1. The driving plate 42 is located on the side of the balance wheel 3 away from the rigid wheel 2. A connecting groove 43 is opened in the center of the driving plate 42. The input shaft 41 and the connecting groove 43 are limitedly fixed by the special shape of the connecting groove 43, or can be further connected and fixed by interference fit, so that the input shaft 41 can drive the driving plate 42 to rotate. The driving pressure plate 42 is in the shape of a round handle. A convex ring 422 is raised on one side of the outer circumference of the driving pressure plate 42 close to the balance wheel 3. An annular inner angle is formed between the convex ring 422 and the outer circumference of the driving pressure plate 42. An arc groove 131 is provided on the edge of the inner circumference of the rear cylinder 13 close to the middle cylinder 12. The annular inner angle of the driving pressure plate 42 and the arc groove 131 of the middle cylinder 12 are arranged opposite to each other, and a plurality of fifth rolling bodies 9 are arranged between the annular inner angle and the arc groove 131. The fifth rolling body 9 abuts against the inner wall of the annular inner angle and the inner wall of the arc groove 131, and a plurality of fifth rolling bodies 9 are formed into an integrated structure by a steel frame to maintain the integrity of all the fifth rolling bodies 9; wherein, the end face of the driving pressure plate 42 facing the balance wheel 3 is a swing driving inclined surface 421, the inclination angle of the inclined surface 421 is the same as the maximum swing amplitude of the balance wheel 3, and the swing driving inclined surface 421 of the driving pressure plate 42 abuts against the end face of the balance wheel 3.

[0055] In particular, by combining the main gear teeth 32 and the auxiliary gear teeth 22 with double elliptical tooth shapes, the function of all gear teeth of the balance wheel 3 and the rigid wheel 2 being involved in the meshing can be achieved.

[0056] Therefore, during the rotation of the input shaft 41, the driving pressure plate 42 will be driven to rotate at the same time. During one rotation, the inclined surface 421 of the driving pressure plate 42 will squeeze the balance wheel 3 to perform synchronous swinging motion in the circumferential direction, so that the edge of the balance wheel 3 will swing periodically at a certain swinging angle in the circumferential direction without rotating. In this process, the main wheel teeth 32 of the balance wheel 3 and the secondary wheel teeth 22 of the rigid wheel 2 will be inserted and removed one by one to achieve periodic meshing. After one week, the rigid wheel 2 rotates one tooth more relative to the balance wheel 3 (that is, the output is opposite to the input), and the balance wheel 3 only swings but does not rotate. The output of the one tooth angle of the rigid wheel 2 is the output speed after deceleration, which achieves the purpose of deceleration. The reduction ratio depends on the number of teeth of the rigid wheel 2.

[0057] In order to make the inclined surface 421 of the driving pressure plate 42 drive the balance wheel 3 to swing more smoothly and reduce the friction between the driving pressure plate 42 and the balance wheel 3. The inclined surface 421 of the driving pressure plate 42 is provided with an annular groove 423, and the end surface of the balance wheel 3 facing the driving pressure plate 42 is provided with a groove 34, the groove 34 and the annular groove 423 correspond to each other, and a plurality of second rolling bodies 6 are arranged between the groove 34 and the annular groove 423, and the second rolling bodies 6 are against the inner walls of the annular groove 423 and the groove 34, so as to reduce the friction between the driving pressure plate 42 and the balance wheel 3 by using the second rolling bodies 6. Among them, a plurality of second rolling bodies 6 are integrated into a structure through a steel frame to maintain the integrity of all second rolling bodies 6.

[0058] In this embodiment, Figure 4 The known harmonic deceleration methods in the prior art have an implicit problem: ① The diameter difference between the inner and outer rings must be greater than one tooth height to achieve the gap between teeth, so the difference in the number of teeth is generally 2 to 6, or even more. If the difference in the number of teeth is too large, the reduction ratio will be small, and the purpose of a large reduction ratio cannot be achieved. ② Reducing the tooth height (too small a tooth height will cause discontinuous meshing transmission) can achieve a large reduction ratio with a relatively small difference in the number of teeth. The idea and principle of this patent are: ① It is necessary to ensure that the inner ring is rigid and does not deform, in order to eliminate the disadvantage of low rigidity caused by the deformation of the thin wall of the inner ring of harmonic deceleration; second, in order to achieve a large reduction ratio, the minimum difference in the number of teeth is selected to be 1 tooth; this causes the diameter difference between the inner and outer rings to be less than the tooth height, causing interference and unable to achieve the gap between teeth. ② In order to reduce the tooth height, the cylindrical inner and outer rings of the harmonic reducer in the prior art are converted into inner and outer cones with the same cone tip (i.e., the balance wheel 3 and rigid wheel 2 structure of this embodiment), and the cylinder can be regarded as a cone with the cone tip infinitely far away; wherein, the tooth height on the cylinder converted into the tooth height in the direction perpendicular to the cone surface is in the cosine relationship of the cone angle, so the larger the cone angle, the smaller the tooth height.

[0059] Therefore, based on the above design ideas, in order to reduce the tooth height of the main gear teeth 32 of the balance wheel 3 and the auxiliary gear teeth 22 of the steel wheel 2, it is necessary to increase the cone angle of the relative end faces of the balance wheel 3 and the steel wheel 2, wherein the cone angle of the end face of the balance wheel 3 facing the steel wheel 2 can even be increased to a plane with a cone angle of 180°, so the end face of the balance wheel 3 facing the steel wheel 2 is a cone surface or even a plane with a large cone angle. Among them, the steel wheel 2 and the balance wheel 3 select large-angle conical gears, and the specific angle must be selected in conjunction with other structures. The cosine relationship of a circle is exactly an ellipse, and considering the issue of giving way, the modified double elliptical tooth profile as the tooth profile of the main gear teeth 32 and the auxiliary gear teeth 22 can achieve 100% meshing of all teeth.

[0060] In this embodiment, in order to reduce the friction between the ball joint 31 and the ball groove 21 and improve the smoothness of the rotational movement of the two, a plurality of third rolling bodies 7 are provided on the inner wall of the ball groove 21, and the peripheral surface of the ball joint 31 abuts against the third rolling bodies 7. Among them, the plurality of third rolling bodies 7 are integrated into an integrated structure by a steel frame to maintain the integrity of all the third rolling bodies 7.

[0061] In this embodiment, both the rigid wheel 2 and the balance wheel 3 are made of rigid materials. Therefore, under the driving action of the harmonic oscillation generator 4, the friction damage of the driving pressure plate 42 on the balance wheel 3 can be reduced, and the meshing damage between the main gear teeth 32 and the auxiliary gear teeth 22 can be reduced, so as to achieve the effect of increasing the service life of the balance wheel 3 and the rigid wheel 2.

[0062] In the present invention, the first rolling body 5, the second rolling body 6, the third rolling body 7, the fourth rolling body 8, and the fifth rolling body 9 can be spherical balls, cylindrical balls, conical balls, arc-shaped balls, etc.

[0063] In this embodiment, in order to improve the rotation or swing flexibility of the entire structure of the swing-type harmonic reducer, a large amount of lubrication is provided in the cylindrical shell 1 to reduce friction, and an oil seal 14 is provided in the gap between the outer peripheral surface of the rigid wheel 2 and the inner wall of the front cylinder 11 of the cylindrical shell 1, and an oil seal 14 is also provided in the gap between the driving pressure plate 42 and the rear cylinder 13. The oil seal 14 is used to prevent leakage of lubricating oil to achieve long-term effective lubrication.

[0064] The beneficial effects of the swing harmonic reducer of this application are as follows:

[0065] (1) Compared with the harmonic reducer of the prior art

[0066] 1. High backlash accuracy. The tooth profile error directly reflects the backlash accuracy. At the same time, the number of meshing teeth is close to 100% (harmonic is generally 33%). The error equalization effect is stronger, making the average backlash (backlash) smaller and the step accuracy higher. Considering the low utilization rate of the effective force of the tooth top part and the purpose of providing a reserve for reuse after tooth wear and storing lubricating oil, part of the tooth top is abandoned, thereby reducing the radial force, so that the actual meshing can be close to 90%, which is much higher than the common harmonic reducer. In this way, it can replace the common harmonic reducer from the perspective of accuracy.

[0067] 2. High rigidity and strong load-carrying capacity: The gear teeth are located on the rigid foundation of the balance wheel 3, and the small deformation does not affect the meshing. In addition, the number of meshing teeth can be close to 90%. Finally, the force is transferred to the cylindrical shell through the spherical constant velocity coupling on the side of the balance wheel 3 (the high rigidity can be increased as required), while the commonly used harmonic reducer flexible wheel gear teeth are located on the elastic deformation flexible wheel cylinder. Finally, the force is transmitted to the output through the gear teeth on the flexible wheel cylinder and the flexible wheel cylinder. Compared with the rigid balance wheel 3 and the thin-walled flexible wheel cylinder, the force transmission rigidity is significantly improved. This directly targets the weaknesses of the existing harmonic reducer and can replace the existing harmonic reducer.

[0068] 3. Long life. The following measures are adopted: ① The rigid wheel 2 matrix itself is a solid rigidity, and the balance wheel 3 matrix is ​​thickened as much as possible to ensure that the teeth are located on the rigid body foundation and reduce the basic deformation of the teeth. ② Reduce the pressure angle of the teeth to below 10°. When transmitting the same torque, the positive pressure between the teeth becomes smaller, and the effective pressure utilization rate is high. Secondly, the number of meshing teeth is nearly three times that of the existing harmonic reduction, and the pressure of a single tooth is reduced to nearly 1 / 3 of it. In this way, firstly, the pressure is small and the deformation is small, and secondly, the small pressure can reduce wear; ③ Select commonly used high-speed steel as the gear material, which has higher heat treatment hardness and is more wear-resistant, which can reduce wear. ④ Reduce relative sliding between teeth: The generator of this patent completes the full tooth height cut-in and exit once in one rotation, while the commonly used harmonic reducer completes the full tooth cut-in and exit twice a week. In this way, it replaces the harmonic reducer from the perspective of long life and strong overload capacity.

[0069] 4. Small starting torque: There is no need to overcome the elastic deformation of the flexible wheel cylinder of the commonly used harmonic reducer, so the starting torque is small.

[0070] 5. The structure is simple, and the number of main parts is equivalent to that of the harmonic reducer: the main parts are also three (rigid wheel 2, balance wheel 3, harmonic generator 4), which is convenient for mass production.

[0071] (2) Compared with the RV reducer of the prior art

[0072] 1. High force transmission rigidity, small additional force, no need for large load bearings. Since the number of teeth meshing at the same time is close to 100% (the theory of double cycloid gear is also 100%), see Figure 3According to the "Tooth Error Comparison and Force Analysis Diagram", due to the cycloidal tooth shape, the tooth force transmission efficiency of the harmonic reducer is much higher than that of the cycloidal tooth when transmitting the same magnitude of force T in the circumferential direction, so the force transmission stiffness is at least equivalent to that of the RV reducer. At the same time, the additional force generated, such as the radial force R, is also small, and the overall structural deformation is small. Compared with the RV harmonic generator structure, the eccentric large bearing required by the cycloidal reducer is removed to achieve high load-bearing, and the radial force R is very small, so the RV reducer can be replaced from the perspective of force transmission stiffness.

[0073] 2. The tooth profile error of this harmonic reducer makes the influence of the inter-tooth clearance on the backlash (backlash) more direct. At the same time, the number of teeth involved in the meshing has a significant averaging effect. Unlike the cycloidal pin gear, which has the effect of amplifying the backlash, the accuracy is significantly improved. Even if the processing accuracy is very low, it will easily exceed the backlash accuracy of the RV reducer, thereby replacing the RV reducer from the perspective of accuracy.

[0074] 3. The RV reducer not only has a primary reduction structure, a secondary reduction cycloid pin reduction structure, but also an output force transmission structure: the cycloid wheel torque force is output to the output force transmission mechanism on the central axis, which directly affects the output backlash error and torque stiffness. This patent is a direct output of the rigid wheel 2. Comprehensive comparison shows that the reducer of this patent has only three main parts, which is much simpler than the RV reducer structure, so the cost is low and it is easier to replace the RV reducer from a cost perspective.

[0075] The implementation methods of the present application are not limited to this. According to the above content of the present application, by utilizing common technical knowledge and customary means in the field, without departing from the above basic technical ideas of the present application, the present application may also make other various forms of modification, replacement or combination, all of which fall within the scope of protection of the present application.

Claims

1. A swing type harmonic reducer, characterized in that: include: Cylindrical shell; A rigid wheel, the rigid wheel is rotatably mounted in the cylindrical housing, the wheel surface of the rigid wheel facing the cylindrical housing is a conical surface, the conical surface of the rigid wheel is provided with auxiliary gear teeth, a ball groove is provided at the center of the wheel surface of the rigid wheel close to the auxiliary gear teeth, and the wheel surface of the rigid wheel away from the ball groove is integrally connected with an output shaft; A balance wheel, the balance wheel is arranged in the cylindrical housing, the wheel surface of the balance wheel facing the rigid wheel is provided with main gear teeth, the number of teeth of the main gear teeth differs from the number of teeth of the auxiliary gear teeth by 1, a ball joint is fixedly provided at the end surface center of the balance wheel close to the main gear teeth, the ball joint and the ball groove are co-centered and rotate and swing in coordination, a swing receiving surface is provided on the side of the balance wheel away from the ball joint, the swing receiving surface is provided with a groove, and the groove of the swing receiving surface is connected to the balance wheel as a whole; A harmonic generator, wherein the harmonic generator has a swing driving inclined surface, the swing receiving surface and the swing driving inclined surface are contact-coupled through rolling bodies in a groove, the rotation of the input shaft drives the swing driving inclined surface to rotate, and under the drive of the swing driving inclined surface, the balance wheel swings periodically in a wave shape along a ring about the ball joint, so that the main gear teeth of the balance wheel gradually mesh with the secondary gear teeth of the rigid wheel, thereby driving the rigid wheel and the output shaft to rotate.

2. The oscillating harmonic reducer according to claim 1, characterized in that: The inner circumference of the cylindrical shell is provided with a plurality of long arc grooves, which are evenly spaced along the circumferential direction and extend along the length direction of the cylindrical shell. The outer circumference of the balance wheel is provided with a plurality of arc grooves, which are evenly spaced along the circumferential direction. The arc grooves of the balance wheel are the same in number and correspond to the long arc grooves of the cylindrical shell, and the arc direction of the arc grooves is consistent with the arc direction of the long arc grooves. A plurality of first rolling bodies are arranged in the arc grooves and the long arc grooves, and the first rolling bodies abut against the inner walls of the relative arc grooves and the long arc grooves.

3. The oscillating harmonic reducer according to claim 2, characterized in that: The swing driving inclined surface is integrally connected with an input shaft, and the input shaft and the cylindrical shell are relatively concentric and only rotate. The input shaft drives the swing driving inclined surface to rotate as a driving source. When rotating, the swing driving inclined surface has a swing angle deviation relative to the ball center of the ball groove. The swing driving inclined surface is provided with an annular groove, and the annular groove is coupled with the swing receiving surface of the balance wheel through rolling body contact. The input shaft drives the swing driving inclined surface to rotate, and the deviation angle generated about the ball joint during rotation drives the swing of the balance wheel.

4. The oscillating harmonic reducer according to claim 1, characterized in that: The end surface of the balance wheel facing the rigid wheel is a large-angle conical surface or can even be a flat surface.

5. The oscillating harmonic reducer according to claim 1 or 4, characterized in that: The gear tooth profiles of the balance wheel and the rigid wheel are double elliptical curve tooth profiles to ensure 100% full tooth engagement between the teeth.

6. The oscillating harmonic reducer according to claim 1, characterized in that: The ball center of the ball joint, the cone top of the balance wheel, the cone top of the rigid wheel, and the eccentricity of the swing driving inclined surface of the harmonic generator during operation are all concentrically arranged.

7. The oscillating harmonic reducer according to claim 1, characterized in that: The inner wall of the ball groove can be coupled to the outer peripheral surface of the ball joint directly or through rolling bodies.

8. The oscillating harmonic reducer according to claim 1, characterized in that: The rigid wheel and the balance wheel are both made of rigid materials.

9. The oscillating harmonic reducer according to claim 1, characterized in that: An oil seal is provided in the gap between the outer peripheral surface of the rigid wheel and the inner wall of the cylindrical shell.

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