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CN-122014812-A - High-precision low-noise harmonic reducer

CN122014812ACN 122014812 ACN122014812 ACN 122014812ACN-122014812-A

Abstract

The invention provides a high-precision low-noise harmonic reducer which comprises a wave generator, a flexible gear and a rigid gear, wherein the wave generator is embedded into the flexible gear and is used for driving the flexible gear to elastically deform, the flexible gear and the rigid gear are in meshed transmission, the wave generator comprises a cam and a flexible bearing sleeved on the cam, the cam profile of the cam adopts a cosine cam profile, the flexible bearing adopts a four-point contact ball bearing structure, the flexible bearing is in interference fit with the cam and the flexible gear, a gear ring of the flexible gear adopts an involute profile structure, a correspondingly meshed rigid gear tooth ring adopts a conjugate tooth profile conjugate with the involute profile, the meshing precision and the smoothness are obviously improved through the precise matching of the involute profile with the rigid gear conjugate tooth profile of a specific parameter of the flexible gear, the adopted cosine cam profile is continuous in first-order derivative and second-order derivative, so that the deformation speed and acceleration of the flexible gear are stably changed, no abrupt impact is caused, the running noise is greatly reduced, and the invention also carries out carburizing quenching of the flexible gear, the rigid gear and the cam nitriding treatment, and the anti-deformation capability can be improved.

Inventors

  • ZHANG ZHENFENG

Assignees

  • 宁波博银谐波科技有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. The high-precision low-noise harmonic reducer comprises a wave generator (1), a flexible gear (2) and a rigid gear (3), wherein the wave generator (1) is embedded into the flexible gear (2) and is used for driving the flexible gear (2) to elastically deform, the flexible gear (2) and the rigid gear (3) are in meshed transmission, and the high-precision low-noise harmonic reducer is characterized in that the wave generator (1) comprises a cam (11) and a flexible bearing (12) sleeved on the cam (11), a cosine cam profile is adopted by a cam profile of the cam (11), a four-point contact ball bearing structure is adopted by the flexible bearing (12), the flexible bearing (12) is in interference fit with the cam (11) and the flexible gear (2), an involute tooth profile structure is adopted by a gear ring of the flexible gear (2), and a conjugate tooth profile conjugated with the involute tooth profile is adopted by a corresponding meshed rigid gear (3) gear ring.
  2. 2. The high-precision low-noise harmonic reducer according to claim 1, characterized in that the cosine cam profile polar equation of the cam (11) is r=r0+w·cos (nθ); Wherein R is the polar diameter, R0 is the base radius of the cam, w is the maximum deformation of the cam, n is the harmonic frequency, and θ is the polar angle.
  3. 3. The high-precision low-noise harmonic reducer is characterized in that the flexible bearing (12) comprises an inner ring (121), an outer ring (122) and a plurality of rolling bodies (123) arranged between the inner ring (121) and the outer ring (122), the rolling bodies (123) are made of zirconia ceramic materials, and the inner ring (121) and the outer ring (122) are made of GCr15 bearing steel materials.
  4. 4. The high-precision low-noise harmonic reducer according to claim 3 is characterized in that the surface of the rolling body (123) is polished, the inner ring (121) and the outer ring (122) are subjected to quenching tempering treatment, and raceways of the inner ring (121) and the outer ring (122) are designed to be convexities.
  5. 5. The high-precision low-noise harmonic reducer according to claim 1, wherein the involute profile of the flexspline (2) is generated by adopting a standard involute equation, and a polar coordinate equation is r=rb/cos alpha; wherein r is the polar diameter of any point of the involute, rb is the base radius of the flexspline, and alpha is the pressure angle of the involute at the point; the calculation formula of the base circle radius rb of the flexible gear is rb=0.5×mzcos alpha 0, wherein m is a modulus, z is the number of teeth, and alpha 0 is the pressure angle of the reference circle.
  6. 6. The high-precision low-noise harmonic reducer is characterized in that specific parameters of the involute profile of the flexible gear (2) are modulus 0.254mm, tooth number 200, reference circle pressure angle 28.6 degrees, tooth top coefficient 0.875, top clearance coefficient 0.25, deflection coefficient 0< x <0.2 and meshing gap 0.5-2 μm, and the deflection coefficient is of positive deflection design and is used for improving meshing depth and avoiding overlapping interference of two sides of a tooth shape.
  7. 7. The high-precision low-noise harmonic reducer according to claim 1, wherein the flexspline (2) is designed in an axial shape modification, and the tooth surface is shaped like a drum in the axial direction.
  8. 8. The high-precision low-noise harmonic reducer is characterized in that the generation method of the conjugate tooth profile of the rigid gear (3) is characterized in that the method is based on the principle of gear engagement and is generated by adopting an envelope method on the premise that cosine cam profile parameters of a wave generator (1) and involute tooth profile parameters of a flexible gear (2) are determined, the coordinate values of discrete points of the tooth profile of the rigid gear (3) are calculated by establishing a flexible gear tooth profile motion equation and combining with an elastic deformation displacement equation of the flexible gear (2) driven by the wave generator (1), and then a three-time spline interpolation algorithm is adopted to smoothly fit and generate a complete tooth profile, and the generation process takes constant meshing clearance as a constraint condition to ensure meshing precision.
  9. 9. The high-precision low-noise harmonic reducer is characterized in that a polyurethane elastic noise reduction coating is arranged on the inner side of a gear ring of the rigid gear (3), and the surface of the coating is provided with diamond-shaped anti-slip textures.
  10. 10. The high-precision low-noise harmonic reducer is characterized in that the flexible gear (2) is made of 20CrMnTi alloy structural steel and is subjected to carburizing and quenching treatment, the rigid gear (3) is made of 40Cr alloy structural steel and is subjected to quenching and tempering treatment, and the cam surface is subjected to nitriding treatment.

Description

High-precision low-noise harmonic reducer Technical Field The invention relates to the technical field of wave generator processing, in particular to a high-precision low-noise harmonic reducer. Background The harmonic reducer is a precise transmission mechanism for realizing motion and power transmission by means of elastic deformation of a flexible gear, has the advantages of large transmission ratio, small volume, light weight, stable transmission and the like, and is widely applied to the fields of high-end equipment such as industrial robots, aerospace equipment, precise machine tools and the like. In the prior art, the design and manufacturing scheme of the harmonic reducer have a plurality of limitations that firstly, a standard involute tooth profile is adopted for a flexible gear, the design of a deflection coefficient is unreasonable, tooth overlapping interference is easy to occur after long-term operation, meanwhile, tooth surfaces of the flexible gear are not subjected to targeted modification, so that the distribution of meshing contact pressure is uneven, fatigue deformation of the flexible gear is aggravated, transmission gaps are increased, positioning accuracy is reduced, secondly, an elliptical contour line is generally adopted for a cam of a wave generator, speed and acceleration mutation exists in the deformation process of the flexible gear, deformation impact and stress concentration are caused, noise is obviously increased under high-speed operation conditions, the deformation resistance of a single-row flexible bearing adopted by a part of scheme is insufficient, vibration and noise problems are further aggravated, thirdly, the materials of the flexible gear, a rigid gear and the flexible bearing are poor in matching property with a heat treatment process, abrasion resistance of the flexible gear surface is insufficient, the flexible bearing rolling body and a roller path are easy to wear, the whole service life of the reducer is short, the maintenance cost is high, and fourthly, the rigid gear profile is designed to be simply adapted to the flexible gear profile, conjugation optimization is not based on the principle of meshing stability and the bearing capacity is limited. Aiming at the core defects of the prior art, the development of a harmonic reducer with the characteristics of high precision, low noise and long service life is needed to meet the high-performance application requirements of the field of high-end equipment. Disclosure of Invention The invention aims to solve the technical problem of providing a harmonic reducer with high precision and low noise performance. The technical scheme is that the high-precision low-noise harmonic reducer comprises a wave generator, a flexible gear and a rigid gear, wherein the wave generator is embedded into the flexible gear and is used for driving the flexible gear to elastically deform, the flexible gear and the rigid gear are in meshed transmission, the wave generator comprises a cam and a flexible bearing sleeved on the cam, a cam profile of the cam adopts a cosine cam profile, the flexible bearing adopts a four-point contact ball bearing structure, the flexible bearing is in interference fit with the cam and the flexible gear, a gear ring of the flexible gear adopts an involute profile structure, and a rigid gear tooth ring which is correspondingly meshed adopts a conjugate tooth profile conjugated with the involute profile. The cam is connected with the input shaft through involute splines, the spline modulus is 1mm, the number of teeth is 18, the pressure angle is 30 degrees, the matching precision is H7/H6, and no gap is reserved in power transmission. Preferably, the polar coordinate equation of the cosine cam profile of the cam is represented by r=R0+w·cos (nθ), wherein R is the polar diameter (i.e., the distance from any point on the cosine profile to the polar origin), R0 is the radius of the cam base circle (value of 17.78 mm), w is the maximum deformation of the cam (value of 0.25 mm), n is the harmonic number (value of 2, corresponding to a double wave harmonic reducer), and θ is the polar angle (the included angle between the polar diameter and the polar axis, and the value range is 0 ° -360 °). The cosine cam profile can make the deformation process of the flexible gear transition smoothly, and reduce deformation impact and stress concentration. Preferably, the flexible bearing comprises an inner ring, an outer ring and a plurality of rolling bodies arranged between the inner ring and the outer ring, wherein the rolling bodies are made of zirconia ceramic materials, and the inner ring and the outer ring are made of GCr15 bearing steel materials. Preferably, the surface of the rolling body is polished, the roughness Ra is less than or equal to 0.01 mu m, the hardness of the inner ring and the outer ring is HRC60-64 after quenching and tempering treatment, the roller paths of the inner ring and the outer ring adopt a c