CN109458441A

CN109458441A - A kind of cam-type wave generator

Info

Publication number: CN109458441A
Application number: CN201811382706.3A
Authority: CN
Inventors: 庄剑毅; 刘青; 汤秀清
Original assignee: Guangzhou Haozhi Electromechanical Co Ltd
Current assignee: Guangzhou Haozhi Electromechanical Co Ltd
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2019-03-12
Anticipated expiration: 2038-11-20
Also published as: CN109458441B

Abstract

The invention discloses a kind of cam-type wave generators, including cam and are sheathed on the flexible bearing of cam, the polar equation of the cam profile of cam are as follows: in 0≤ψ≤β-β₁Section, ρ_Δ=r+ [ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]；In β-β₁The section≤ψ≤β, ρ_Δ=r+ [ω₀ ^*m/(A‑4/π)][Acosψ+ψsinβsinψ‑4/π]+0.5Δ₀{1+cos[π(ψ‑β)/β₁]}；In β≤ψ≤β+β₂Section, ρ_Δ=r+ [ω₀ ^*m/(A‑4/π)][Bsinψ+(π/2‑ψ)cosβcosψ‑4/π]+0.5Δ₀{1+cos[π(ψ‑β)/β₂]}；In β+β₂The section≤ψ≤90, ρ_Δ=r+ [ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]；Cam profile is acted on using four power of amendment type, bearing capacity, efficiency and the service life of harmonic speed reducer complete machine is promoted, makees the cam contour curve shape of use by correcting force F, improve the deformation and stress condition of flexible bearing；By optimizing the parameter value of cam contour curve, improve the stress value and meshing quality of flexbile gear.

Description

Cam type wave generator

Technical Field

The invention relates to a wave generator, in particular to a cam-type wave generator.

Background

The harmonic reducer is a transmission device which uses the wave generator to make the flexible gear generate controllable elastic deformation wave, and realizes motion and power transmission by the interaction with the rigid gear. The wave generator is a component which makes the flexible gear generate continuous deformation wave, and the form and geometric parameters of the wave generator not only determine the shape of the original curve of the harmonic gear drive, but also have important influence on the meshing performance of the drive and the strength of the flexible gear.

The wave generators may be classified into various types of wave generators, such as a cam type, a roller type, and a disc type, according to the structure. The cam type wave generator can enable the meshing of the flexible gear and the rigid gear to reach an ideal state, and has stable operation, high precision and higher efficiency; and because the stress distribution state in the flexible gear is improved, the bearing capacity is high, and the flexible gear is suitable for transmission with higher requirement on transmission precision. At present, the harmonic reducer mainly adopts a cam type wave generator.

The cam type wave generator is composed of a cam designed and made according to the motion rule of flexible wheel deformation wave, and a flexible bearing capable of working in a deformation state is sleeved on the outer surface of the cam. The deformation shape and the deformation amount of the cam directly determine the deformation shape and the deformation amount of the flexible gear, and are very important for the working capacity of the whole harmonic reducer, so the design of the cam profile is the main content of the design of the cam type wave generator.

The four-force cam profile can improve the stress value and the meshing quality of the flexible gear by changing the action angle (noted as β) of the force F, and is better than the cosine cam in overall performance.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a cam-type wave generator with high use efficiency and long service life.

The purpose of the invention is realized by adopting the following technical scheme:

a cam type wave generator comprises a cam and a flexible bearing sleeved on the cam, wherein the polar coordinate equation of the cam contour line of the cam is that psi is more than or equal to 0 and less than or equal to β - β₁Interval ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]At β - β₁Interval of phi ≤ and β, rho_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₁]Phi is not less than β but not more than β + β₂Interval ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₂]At β + β₂Phi is not less than 90 interval, rho_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]Wherein A is sin β + (pi/2- β) cos β, B is cos β + β sin β, r is the radius of the flexible wheel, m is the modulus of the flexible wheel, omega₀ ^*The maximum radial deformation coefficient; delta₀Defining a numerical value according to design requirements for correcting extreme value, β is a force action angle, β₁For correction range near the major axis β₂Is the correction range near the minor axis.

Further, ω is₀ ^*＝ω₀M, wherein ω₀Is the maximum radial deflection.

Further, when the structural length-diameter ratio k of the flexible gear is>0.4, number of teeth Z>130, ω₀ ^*1.0 to 1.3, β is 25 to 35 degrees, delta₀Is (0.01 to 0.04) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is>0.4, number of teeth Z>130, ω₀ ^*1.1 to 1.2, β is 25 to 30 degrees, delta₀Is (0.02-0.03) omega₀ ^*m，β₁Is 20 to β₂Is 20-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is>0.4, when the number of teeth Z is less than or equal to 130, omega₀ ^*0.7 to 1.0, β is 25 to 35 DEG, Delta₀Is (0.01 to 0.04) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is>0.4, when the number of teeth Z is less than or equal to 130, omega₀ ^*0.8 to 0.9, β is 30 to 35 degrees, delta₀Is (0.02-0.03) omega₀ ^*m，β₁Is 20 to β₂Is 20-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 0.4>130, ω₀ ^*1.0 to 1.3, β is 15 to 25 degrees, delta₀Is (0.01-0.03) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 0.4>130, ω₀ ^*1.2 to 1.3, β is 20 to 25 degrees, delta₀Is (0.01-0.02) omega₀ ^*m，β₁Is 10 to β₂Is 20-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 130, omega₀ ^*0.7 to 1.0, β is 15 to 25 DEG, Delta₀Is (0.01-0.03) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

Further, when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 130, omega₀ ^*0.8 to 0.9, β is 15 to 20 degrees, delta₀Is (0.01-0.02) omega₀ ^*m，β₁Is 10 to β₂Is 20-40 degrees.

Compared with the prior art, the cam of the cam type wave generator adopts the modified four-force action cam profile to improve the bearing capacity, efficiency and service life of the whole harmonic reducer, and the deformation and stress conditions of the flexible bearing are improved by modifying the shape of the cam profile curve at the action of the force F; by optimizing the parameter value of the convex profile curve, the stress value and the meshing quality of the flexible gear are improved.

Drawings

FIG. 1 is a schematic view of a prior art lobed wave generator;

FIG. 2 is a simplified schematic diagram of a flexspline thin-walled ring;

FIG. 3 is a cam profile of the cam wave generator of FIG. 1 under four forces;

FIG. 4 is a front and rear comparative view of a cam profile modification of a cam of the cam wave generator of the present invention;

FIG. 5 is an enlarged view of FIG. 4 at cam wave generator A;

fig. 6 is a polar coordinate comparison before and after a first quadrant cam profile modification of the cam generator of fig. 4.

In the figure: 10. a cam; 20. a compliant bearing; 30. a flexible gear.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the prior art, as shown in fig. 1, a cam type wave generator is composed of a cam 10 designed and manufactured according to the motion law of a deformation wave of a flexible gear 30, and a flexible bearing 20 capable of working in a deformation state is sleeved outside the cam 10. The deformed shape and amount of deformation of the cam 10 directly determine the deformed shape and amount of deformation of the flexspline 30, and are important to the operation capability of the entire harmonic reducer.

In the prior art, the four force action cam profile is expressed as follows: the flexspline 30 can be regarded as oneAs shown in FIG. 3 (the thin-wall ring is simplified into a circle), the thin-wall ring deforms under the action of four forces F with an included angle of β, the neutral circle deforms along with the deformation, and the deformed neutral circle is a four-force action cam profile line₀(ii) a Radial deformation omega and omega of other points (with an included angle phi with the X axis) on the neutral circle₀The relationship of (a) to (b) is as follows:

in the interval of phi being more than or equal to 0 and less than or equal to β,

ω＝[ω₀/(A-4/π)][Acosψ+ψsinβsinψ-4/π](1)

wherein, A is sin β + (pi/2- β) cos β, B is cos β + β sin β, omega is₀The maximum radial deformation, omega the radial deformation omega, and β the included angle of force.

When the phi is not less than β and not more than 90,

ω＝[ω₀/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π](2)

wherein, A is sin β + (pi/2- β) cos β, B is cos β + β sin β, omega is₀Maximum radial deflection, omega radial deflection, and β force angle.

The included angle between the point P on the neutral circle and the X axis before deformation is ∠ POX, and the point P 'reaching the cam profile after deformation is considered to remain unchanged in engineering application, namely the included angle ∠ P' OX is ∠ POX.

At the same time, ω₀The ratio of the modulus m of the flexspline 30 to the maximum radial deformation coefficient ω₀ ^*Namely:

ω₀＝ω₀ ^*m (3)

thus, the polar equation for the four force action cam profile can be expressed as:

ρ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π](4)

wherein A is sin β + (pi/2- β) cos β, m is modulus of the flexible wheel 30, omega₀ ^*The maximum radial deflection coefficient, β the force angle, and r the radius of the flexspline 30.

When the phi is not less than β and not more than 90,

ρ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π](5)

wherein, B is cos β + β sin β, m is the modulus of the flexible wheel 30, omega₀ ^*The maximum radial deflection coefficient, β the force angle, and r the radius of the flexspline 30.

In general, when designing the cam profile, r and m are known, by adjusting ω₀ ^*And β, the shape of the cam profile can be changed to ultimately adjust the compliance 30 deformation, stress level, and engagement quality.

In the present invention, based on the conventional four-force action cam profile, the angle β is used as a reference, and a certain range of [ - β 1, β 2 ] is set for both sides]The curve point (b) is subjected to local radial deformation correction, and if the correction amount is Δ, the corrected four-force action cam profile is: rho_Δ＝ρ+Δ。

By using cosine correction, Δ is designed as follows:

phi is more than or equal to 0 and less than or equal to β - β₁Interval, Δ ═ 0;

at β - β₁The interval phi is not less than β, and delta is 0.5 delta₀{1+cos[π(ψ-β)/β₁]} (6)

Phi is not less than β and not more than β + β₂Interval, Δ ═ 0.5 Δ₀{1+cos[π(ψ-β)/β₂]} (7)

At β + β₂The phi is not less than 90, and delta is 0;

wherein, Delta₀To define the value for the extreme correction amount according to the design requirement β₁To approximate the correction range of the major axis, β₂Is the correction range near the minor axis.

The polar equation for the modified four-force action cam profile may then be expressed as:

phi is more than or equal to 0 and less than or equal to β - β₁The interval of time is,

ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]； (8)

At β - β₁The psi is not less than β,

ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₁]}； (9)

wherein A is sin β + (pi/2- β) cos β, m is modulus of the flexible wheel 30, omega₀ ^*The maximum radial deformation coefficient, β the included angle of force, r the radius of the flexible wheel 30, and delta₀β being extreme values of correction₁A correction range near the long axis.

Phi is not less than β and not more than β + β₂The interval of time is,

ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₂]}； (10)

wherein, B is cos β + β sin β, m is the modulus of the flexible wheel 30, omega₀ ^*The maximum radial deformation coefficient, β the included angle of force, r the radius of the flexible wheel 30, and delta₀β being extreme values of correction₂Is the correction range near the minor axis.

At β + β₂The psi is not less than 90,

ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]； (11)

When designing the cam profile, r and m are known, and ω is determined to completely determine the shape of the cam profile₀ ^*、β、Δ₀、β₁、β₂And the values of the 5 parameters are equal. The values of these parameters are related to the structural aspect ratio k (as shown in fig. 1, k ═ d/L) and the number of teeth Z of the flexspline 30, and the preferred ranges are shown in table 1.

TABLE 1

The optimum value ranges are shown in table 2.

TABLE 2

The effect of the modified four force action cam profile is illustrated below.

Taking a harmonic reducer of a certain specification as an example, it is known that k is 0.5 > 0.4, Z is 100, r is 40, and m is 0.8;

according to Table 2, ω₀ ^*、β、Δ₀、β₁、β₂The values of the 5 parameters are as follows:

ω₀ ^*＝0.9，β＝30°，Δ₀＝0.02·ω₀ ^*·m＝0.014，β₁＝20°，β₂＝30°。

according to the equations 4 and 5, the cam profile equation before repair is obtained as follows:

ρ＝40+[0.9*0.8/(1.407-4/π)][1.407*cosψ+ψsin30°*sinψ-4/π],ψ∈[0,30°]；

ρ＝40+[0.9*0.8/(1.407-4/π)][1.128*sinψ+(π/2-ψ)cos30°*cosψ-4/π],ψ∈[0,β]。

wherein, A is 30 degree (+ (pi/2-30 degree)) cos30 degree is 1.407,

B＝cos30°+30°sin30°＝1.128。

an unmodified cam profile and unmodified cam polar coordinates can be derived.

According to the following formula:

ρ_Δ＝40+[0.9*0.8/(1.407-4/π)][1.407*cosψ+ψsin30°sinψ-4/π]，ψ∈[0,10°]；

ρ_Δ＝40+[0.9*0.8/(1.407-4/π)][1.407*cosψ+ψsin30°sinψ-4/π]+0.5*0.014*{1+cos[π(ψ-30°)/20°]}，ψ∈[10°，30°]；

ρ_Δ＝r+[0.9*0.8/(1.407-4/π)][1.128*sinψ+(π/2-ψ)cos30°*cosψ-4/π]+0.5*0.014*{1+cos[π(ψ-30°)/30°]}，ψ∈[30°，60°]；

ρ_Δ＝40+[0.9*0.8/(1.407-4/π)][1.128*sinψ+(π/2-ψ)cos30°*cosψ-4/π]，ψ∈[60°，90°]；

wherein,

A＝sin30°+(π/2-30°)cos30°＝1.407,

B＝cos30°+30°sin30°＝1.128。

the cam profile after the modification and the polar coordinates of the cam after the modification can be obtained.

In summary, the modified cam profile front-rear pair is shown in fig. 4 and 5, and the modified first quadrant cam front-rear polar coordinates (with the unmodified cam profile as the reference) are shown in fig. 6.

The invention improves the deformation and stress conditions of the flexible bearing 20 by correcting the convex profile curve shape of the action of the force F; meanwhile, the stress value and the meshing quality of the flexible gear 30 are improved by optimizing the parameter value of the convex profile curve; therefore, the bearing capacity and the service life of the whole harmonic reducer are greatly improved, and meanwhile, the transmission efficiency is also improved slightly.

Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes should fall within the scope of the claims of the present invention.

Claims

1. A cam-type wave generator comprises a cam and a flexible bearing sleeved on the cam, and is characterized in that: the polar coordinate equation of the cam profile line of the cam is as follows:

phi is more than or equal to 0 and less than or equal to β - β₁Interval ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]；

At β - β₁Interval of phi ≤ and β, rho_Δ＝r+[ω₀ ^*m/(A-4/π)][Acosψ+ψsinβsinψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₁]}；

Phi is not less than β and not more than β + β₂Interval ρ_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]+0.5Δ₀{1+cos[π(ψ-β)/β₂]}；

At β + β₂Phi is not less than 90 interval, rho_Δ＝r+[ω₀ ^*m/(A-4/π)][Bsinψ+(π/2-ψ)cosβcosψ-4/π]；

Wherein, A is sin β + (pi/2- β) cos β, B is cos β + β sin β, r is the radius of the flexible wheel, m is the modulus of the flexible wheel, omega₀ ^*The maximum radial deformation coefficient; delta₀Defining a numerical value according to design requirements for correcting extreme value, β is a force action angle, β₁For correction range near the major axis β₂Is the correction range near the minor axis.

2. The cam-type wave generator of claim 1, wherein: the omega₀ ^*＝ω₀M, wherein ω₀Is the maximum radial deflection.

3. The cam-type wave generator of claim 1, wherein: when the structural length-diameter ratio k of the flexible gear is>0.4, number of teeth Z>130, ω₀ ^*1.0 to 1.3, β is 25 to 35 degrees, delta₀Is (0.01 to 0.04) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

4. The cam-type wave generator of claim 3, wherein: when the structural length-diameter ratio k of the flexible gear is>0.4, number of teeth Z>130, ω₀ ^*1.1 to 1.2, β is 25 to 30 degrees, delta₀Is (0.02-0.03) omega₀ ^*m，β₁Is 20 to β₂Is 20-40 degrees.

5. The cam-type wave generator of claim 1, wherein: when the structure of the flexible gearAspect ratio k>0.4, when the number of teeth Z is less than or equal to 130, omega₀ ^*0.7 to 1.0, β is 25 to 35 DEG, Delta₀Is (0.01 to 0.04) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

6. The cam-type wave generator of claim 5, wherein: when the structural length-diameter ratio k of the flexible gear is>0.4, when the number of teeth Z is less than or equal to 130, omega₀ ^*0.8 to 0.9, β is 30 to 35 degrees, delta₀Is (0.02-0.03) omega₀ ^*m，β₁Is 20 to β₂Is 20-40 degrees.

7. The cam-type wave generator of claim 1, wherein: when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4, the number of teeth Z>130, ω₀ ^*1.0 to 1.3, β is 15 to 25 degrees, delta₀Is (0.01-0.03) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

8. The cam-type wave generator of claim 7, wherein: when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4, the number of teeth Z>130, ω₀ ^*1.2 to 1.3, β is 20 to 25 degrees, delta₀Is (0.01-0.02) omega₀ ^*m，β₁Is 10 to β₂Is 20-40 degrees.

9. The cam-type wave generator of claim 1, wherein: when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 130, omega₀ ^*0.7 to 1.0, β is 15 to 25 DEG, Delta₀Is (0.01-0.03) omega₀ ^*m，β₁Is 5 to β₂Is 5-40 degrees.

10. Cam-type wave generator according to claim 9, characterized in thatIn the following steps: when the structural length-diameter ratio k of the flexible gear is less than or equal to 0.4 and the tooth number Z is less than or equal to 130, omega₀ ^*0.8 to 0.9, β is 15 to 20 degrees, delta₀Is (0.01-0.02) omega₀ ^*m，β₁Is 10 to β₂Is 20-40 degrees.