WO2017215621A1

WO2017215621A1 - Tooth profile design method for three-dimensional high-rigidity harmonic speed reducer

Info

Publication number: WO2017215621A1
Application number: PCT/CN2017/088374
Authority: WO
Inventors: 吴文
Original assignee: 南通慧幸智能科技有限公司
Priority date: 2016-06-16
Filing date: 2017-06-15
Publication date: 2017-12-21
Also published as: CN106090185A; CN106090185B

Abstract

Disclosed is a tooth profile design method for a three-dimensional high-rigidity harmonic speed reducer. The harmonic speed reducer comprises a wave generator (4), a rigid gear (2) and a flexible gear (3). The rigid gear (2) is engaged with the flexible gear (3). The wave generator (4) is in contact with an inner wall of the flexible gear (3). Both the rigid gear (2) and the flexible gear (3) are involute gears. The tooth number of the rigid gear (2) is Z₁, and the tooth number of the flexible gear (3) is Z₂, where Z₁ - Z₂ = 2. The modification coefficient of the rigid gear (2) is x₁, the modification coefficient of the flexible gear (3) is x₂, where x₁ < x₂, and the modification difference is Δx = x₁- x₂. Material removing and profile modification are performed on two sides or the top of the addendum circle of the rigid gear (2) and/or the flexible gear (3). The implementation of the tooth profile design method is convenient, the machining cost is lower, the purpose of large-area engagement is achieved, the torsional deformation resistance and bearing capacity of the harmonic speed reducer are improved, and the service life of the harmonic speed reducer is prolonged.

Description

Tooth shape design method of three-dimensional high rigidity harmonic reducer

The present invention claims priority to Chinese Patent Application No. 201610430574.1, entitled "Tooth Design Method for Three-Dimensional High-Rigid Harmonic Reducer", submitted to the State Intellectual Property Office of China on June 16, 2016.

Technical field

The present application generally relates to the technical field of harmonic reducers, and more particularly to a tooth design method for a three-dimensional high-rigidity harmonic reducer.

Background technique

Rigidity is an important indicator for evaluating the performance of harmonic gear reducers. The good rigidity indicates that the harmonic gear reducer has good resistance to torsional deformation, large bearing capacity and long service life.

At present, there are mainly the following methods for improving the rigidity of the harmonic gear reduction device:

(1) Improve the gear strength by changing the gear material. The Chinese patent document CN201180014539.7 discloses a technical solution for heat-treating the flex wheel of the harmonic gear reduction device to change the crystal phase structure of the metal to improve the strength of the gear. The Chinese patent document CN201410372571.8 discloses that a gear material with high fatigue strength can be obtained by changing the composition and proportion of the metal material of the gear, and the above two methods increase the manufacturing cost although feasible;

(2) Increasing the meshing contact area by changing the tooth shape. Through the tooth design, more meshing teeth and meshing area can be obtained. Under the same load, the average load per tooth will be reduced, so that the life of the harmonic gear reducer is extended and the maximum can be withstood. The load will also become larger. At present, the tooth profile of the harmonic gear reduction device mainly has a circular arc tooth shape, an involute tooth shape, and a bevel tooth shape, and each of these tooth shapes has its own advantages and disadvantages. According to the Chinese patent document CN103748382A, according to the formula of the motion trajectory of the middle surface of the flexible wheel, the different sections of the flexible wheel are differently displaced to obtain a similar curve tooth shape as the tooth shape of the rigid-flex wheel, and according to the deviation coefficient of the flexible wheel The shape of the tooth surface of the soft tooth has been repaired in three directions. Although there is a certain theoretical basis, the actual production cannot be processed. The Chinese patent document CN201410309903.8 discloses that the enveloping and fitting calculation is carried out on the tooth root arc portion of the rigid wheel using the tooth tooth motion trajectory of the front section of the flexible wheel; the flexible wheel rear cross section is used in the arc portion of the tooth top of the rigid wheel. The enveloping and fitting calculation of the tooth tooth trajectory results in a double arc tooth shape with a common tangent, so that the flexible wheel and the rigid wheel are continuously conjugated over the entire meshing interval, although the number of meshing teeth can be increased and the meshing contact surface can be increased. However, because special tools are required for machining, and the shape of the cutting tool is complicated, the cost is high and it is not easy to promote. U.S. Patent No. 6,467,375 discloses the use of an involute profile, which can reduce the cost of tooling. However, the engagement of the flexible wheel of this solution only maintains good meshing at the opening and does not form a large area of engagement. Limited capacity and insufficient service life.

Summary of the invention

In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a tooth type design method for a three-dimensional high-rigidity harmonic reducer, which is capable of solving the problem of poor resistance to torsional deformation of a harmonic gear reducer existing in the prior art, and carrying The problem is small capacity, short service life and difficult gear processing.

The present application provides a tooth type design method for a three-dimensional high-rigidity harmonic reducer including a wave generator, a rigid wheel and a flexible wheel, the rigid wheel meshes with the flexible wheel, and the inner wall of the wave generator and the flexible wheel In contact, the rigid wheel and the flexible wheel are both involute gears, the number of teeth of the rigid wheel is Z ₁ , the number of teeth of the flexible wheel is Z ₂ , and Z ₁ -Z ₂ = 2; The displacement coefficient of the wheel is x ₁ , the displacement coefficient x _{2 of} the flex wheel, x ₁ <x ₂ , the displacement difference Δx=x ₁ -x ₂ ;

A material removal treatment is performed on both sides or the top of the toothed circle of the rigid wheel and/or the flexible wheel.

According to the above solution provided by the present invention, both the rigid wheel and the flexible wheel are involute gears, and can be processed by conventional gear shaping and hobbing, without any processing difficulties, and is easy to implement and the processing cost is also low. The rigid wheel and the soft wheel form a negative displacement difference, achieving the purpose of large-area meshing, and improving the anti-torsion deformation capability, bearing capacity and service life of the harmonic reducer. In addition, as the meshing area is increased, in order to prevent interference between the rigid wheel and the flex wheel, the material removal processing is performed on both sides or the top of the tooth tip circle of the rigid wheel and/or the flexible wheel, that is, in the tooth. The certain material is removed from the web, so that there is no interference between the gears of the rigid wheel and the flexible wheel, which not only meets the requirements of high load capacity, but also prolongs the service life of the rigid wheel and the flexible wheel.

DRAWINGS

Other features, objects, and advantages of the present application will become more apparent from the detailed description of the accompanying drawings.

1 is a schematic structural diagram of a harmonic reducer obtained by implementing a tooth type design method for a three-dimensional high-rigidity harmonic reducer according to an embodiment of the present invention;

2 is a schematic view showing a movement trajectory of a positive displacement differential flex wheel relative to a rigid wheel;

Figure 3 is a schematic view showing the movement trajectory of the zero-variable difference soft wheel relative to the rigid wheel;

4 is a schematic view showing a movement trajectory of a negative displacement differential wheel relative to a rigid wheel;

Figure 5 is a schematic view of the negative displacement difference meshing area;

Figure 6 is a schematic view of the positive displacement difference meshing area;

Figure 7 is a schematic view showing the tooth profile of the rigid wheel and the shape of the gear shaping cutter;

Figure 8 is a schematic view of a tooth profile of a flex wheel and a tooth profile of a hobbing cutter;

9 is a schematic diagram of interference judgment between a rigid wheel and a flexible wheel;

Figure 10 is a schematic view of three repairing shapes of the round top chamfer of the soft tooth;

Figure 11 is a cross-sectional view of the tooth surface of the flex spline after the chamfer is rounded;

Figure 12 is a schematic view showing the movement of the top of the soft tooth after round chamfering;

Figure 13 is a schematic view showing three maintenance shapes after the dome portion of the soft tooth tip is removed;

Figure 14 is a cross-sectional view showing the dome portion of the tooth surface in the direction of the tooth surface of the flex spun;

Figure 15 is a schematic view showing the movement of the dome portion of the flexible gear tooth tip after removal;

Figure 16 is a schematic view showing three maintenance shapes after the dome portion of the rigid tooth tip is removed;

Figure 17 is a cross-sectional view showing the dome portion of the tooth-toothed surface in the direction of the tooth surface;

Figure 18 is a schematic view showing the movement of the dome of the rigid tooth tip after removal;

Figure 19 is a schematic view showing the movement path of the flexible wheel opening;

Figure 20 is a schematic view showing the movement path of the middle of the fla

detailed description

The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention, rather than the invention. It should also be noted that, for the convenience of description, only parts related to the invention are shown in the drawings.

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 , a harmonic reducer obtained by implementing a tooth type design method for a three-dimensional high-rigidity harmonic reducer according to an embodiment of the present invention, wherein the harmonic reducer includes a wave generator 4 and a rigid wheel 2 The flexible wheel 3, the rigid wheel 2 meshes with the flexible wheel 3, the wave generator 4 is in contact with the inner wall of the flexible wheel 3, the rigid wheel 2 and the flexible wheel 3 are both involute gears, and the wave generator 4 is composed of an elliptical cam and a flexible bearing The elliptical cam is inserted in the inner ring of the flexible bearing, and the outer ring of the flexible bearing is in contact with the inner wall of the flexible wheel 3, and the flexible wheel 3 is also deformed into an elliptical shape and meshes with the rigid wheel at the long axis, and the flexible wheel 3 The short shaft is completely disengaged from the rigid wheel 2. The number of teeth of the rigid wheel 2 is Z ₁ , the number of teeth of the flex wheel 3 is Z ₂ , and Z ₁ -Z ₂ = 2; the coefficient of displacement of the rigid wheel 2 is x ₁ , and the coefficient of displacement of the flex wheel 3 is x ₂ , x ₁ <x ₂ , the displacement difference Δx=x ₁ -x ₂ ; the material removal treatment is performed on both sides or the top of the addendum 2 and/or the addendum circle of the flex wheel 3. According to the actual situation, the parts on both sides of the tooth top circle of the flexible wheel 3 can be removed by cutting off the material to prevent the interference, and the top of the tooth top circle of the rigid wheel 2 can be cut off. The method is removed to achieve the purpose of shape modification to prevent interference, and of course, the portion on both sides of the tooth top circle of the flexible wheel 3 and the top material of the addendum circle of the rigid wheel 2 can be removed at the same time, of course, the rigid wheel 2 The material removal of the flexible wheel 3 can be modified not only in the manner described above.

According to the above solution provided by the present invention, both the rigid wheel and the flexible wheel are involute gears, and can be processed by conventional gear shaping and hobbing, without any processing difficulties, and is easy to implement and the processing cost is also low. The rigid wheel and the soft wheel form a negative displacement difference, achieving the purpose of large-area meshing, and improving the anti-torsion deformation capability, bearing capacity and service life of the harmonic reducer. In addition, as the meshing area is increased, in order to prevent interference between the rigid wheel and the flex wheel, the material removal processing is performed on both sides or the top of the tooth tip circle of the rigid wheel and/or the flexible wheel, that is, in the tooth. A certain amount of material is removed from the web so that there is no gap between the ring of the rigid wheel and the flexible wheel. Interference is currently occurring, which not only satisfies the demand for high load capacity, but also prolongs the service life of the rigid wheel and the flexible wheel.

The top circle of the soft tooth is tangent to the involute flank on both sides of the flex wheel, so it is very suitable to use the trajectory of the trajectory to explain the condition of meshing with the rigid wheel. The technical solution of the present invention will be described in detail below with reference to three comparative examples. The negative displacement difference is used to realize the large-area meshing between the rigid wheel and the flexible wheel, and the ability to resist torsional deformation is strong, the bearing capacity is large, and the service life is long.

As shown in Fig. 2, when the displacement difference between the rigid wheel and the flexible wheel is positive, at the opening of the flexible wheel, the trajectory of the center of the top circle of the soft tooth is obviously crossed and turned, which is for the tooth profile of the rigid wheel. Engagement occurs if it leaves quickly and only a few teeth come into contact.

As shown in Fig. 3, when the displacement difference between the rigid wheel and the flexible wheel is zero, at the opening of the flexible wheel, the center of the circular motion of the top circle of the soft tooth forms a sharp shape at the highest point, although there is no cross turn, the flexible wheel The distance between the center of the addendum circle and the tooth profile of the rigid wheel is increasing, which means that only a few teeth of the tip end are in contact with the rigid wheel and gradually drift away.

As shown in Fig. 4, when the displacement difference between the rigid wheel and the flexible wheel is negative, at the opening of the flexible wheel, the trajectory of the center of the top circle of the soft tooth is rounded at the highest point and the tooth profile of the rigid wheel is also step by step. Almost equidistant travel paths, which means that more meshing teeth are available, creating a wide range of contacts.

However, the meshing condition of the soft teeth at the opening does not reproduce other cross sections, and the axial length of the ellipse along the axis of the flex wheel becomes smaller with the axial length of the ellipse, and the trajectory of each cross section also changes. The crossover phenomenon of the positive displacement gradually disappears, and the bottom of the soft tooth becomes a trajectory similar to the negative displacement, and the negative displacement is closer to the tooth profile of the rigid wheel under the trajectory, which means the rigid and flexible wheels. Interference begins to occur between the two, and the positive displacement and zero displacement do not have this phenomenon.

5 and 6 respectively show the reduction ratio of the 80th harmonic gear reducer negative displacement difference and the positive displacement difference of the meshing area, compared with the positive displacement difference of the meshing area, Figure 5, Figure 6, the horizontal axis In order to determine the number of teeth, the vertical axis is the position of the tooth width from the front to the front, wherein the opening is the front section, that is, the position of the longitudinal axis 10. The position indicating X in the figure is the interference position, and the position indicating O is the meshing position. In the application of the present application, the amount of meshing is 17.5%, and the amount of meshing of the positive displacement is only 2%. The meshing area of the negative displacement difference of this patent is much higher than the positive displacement difference, but the interference area from the middle to the bottom is also large, so the tooth shape of the negative wheel and/or the rigid wheel of the negative displacement must be repaired. Shape, after the middle to bottom interference portion is removed, the negative displacement difference meshing area is still much higher than the positive displacement difference, and therefore, from the middle of the rigid wheel and/or the flexible wheel tooth to the bottom The material removal treatment is described. In addition, the distribution of the meshing is not concentrated on the middle long axis (the 31st to 49th tooth positions), and the bottom direction is diffused to both sides (19-33, 47-61), which forms a dispersion effect on the load-bearing stress of the flexible wheel. Helps to greatly increase the life of the reducer. It can be seen that the harmonic gear reducer with negative displacement has higher bearing capacity and longer life than the positive-variable harmonic gear reducer.

Referring to Figures 7 and 8, in order to make the harmonic reducer have a large meshing area and avoid the interference between the flexible wheel and the rigid wheel, the method is adopted when the reduction ratio of the harmonic reducer is less than or equal to 60. The wheel is made of gear teeth, the full height coefficient of the gear of the rigid wheel h ₁ *=1.0～1.3, the pitch pitch coefficient P _D1 *=0.9～1.3, the tooth height coefficient of the gear of the rigid wheel is h*=1.1～ 1.4, the tooth tip radius coefficient r _d1 *=0.3~0.6, the root radius coefficient of the pinion tooth r _a1 *=0.4~1.0; the soft wheel is made by hobbing, the full height coefficient of the tooth of the soft wheel h ₂ *=1.1～1.4, the pitch pitch coefficient of the hobbing cutter for machining the flexible wheel P _D2 *=0.7～1.1, the radius coefficient of the hobbing cutter tip circle r _d2 *=0.5～0.9, the radius coefficient of the root of the hobbing cutter r _a2 *=0.3 to 0.7; soft tooth tip clearance coefficient j ₁ *=0.1 to 0.3, soft tooth root gap coefficient j ₂ *=0.1 to 0.4, meshing tooth height coefficient H _w *=0.9 to 1.2. The headgear coefficient of the soft tooth is the ratio of the gap between the bottom of the rigid tooth to the top of the soft tooth and the modulus. The coefficient of the root of the soft tooth is the ratio of the gap between the tooth tip of the rigid wheel to the root of the soft tooth and the modulus. The high coefficient is the ratio of the distance between the tooth tip of the engagement position and the tip of the adjacent rigid wheel to the modulus.

In order to make the harmonic reducer have a large meshing area and avoid the interference between the flexible wheel and the rigid wheel, the method is adopted when the reduction ratio of the harmonic reducer is greater than 60, the rigid wheel is processed by the gear shaping, and the rigid wheel is formed. The full height coefficient of the tooth h ₁ *=1.2～1.6, the pitch pitch coefficient P _D1 *=0.9～1.4, the tooth height coefficient h*=1.1～1.4 of the gear shaping cutter of the processing wheel, the tip radius coefficient of the gear shaping cutter r _d1 *=0.2～0.6, the radius coefficient of the root of the gear tooth is r _a1 *=0.6～0.9; the soft wheel is made of hobbing, the full height coefficient of the tooth of the soft wheel is h ₂ *=1.3～1.6, the processing soft wheel The pitch pitch coefficient of the hobbing cutter is P _D2 *=0.7～1.2, the radish cutter tip circle radius coefficient r _d2 *=0.5～0.8, the hobbing cutter root circle radius coefficient r _a2 *=0.4～0.8; The tooth head clearance coefficient j ₁ *=0.1 to 0.3, the soft tooth root gap coefficient j ₂ *=0.2 to 0.5, and the meshing tooth height coefficient H _w *=1.0 to 1.3.

Further, referring to FIG. 9, the interference starting position of the rigid wheel and the flexible wheel is obtained according to the following relationship, and the material removal processing is performed on the bottom of the rigid wheel and/or the flexible wheel at least from the interference starting position. ;

X ₃ =-r _b1 ·sin(α'-δ);

Y ₃ =r _b1 ·cos(α'-δ);

_{l = d a1 / 2-j} 2 + r a1;

X ₄ = l·cosβ;

Y ₄ = l·sinβ;

Where d _w1 is the rigid wheel meshing pitch diameter, α' is the meshing pressure angle, α is the tool pressure angle, T is the reduction ratio, r _b1 is the rigid wheel base circle radius, and δ is the rigid wheel tooth profile declination, that is, just The angle between the gear tooth profile and the center line of the rigid gear tooth, d _a1 is the outer diameter of the rigid wheel, j ₂ is the soft tooth root clearance, r _a1 is the radius of the rigid tooth tip circle, r _b1 is the radius of the rigid wheel base circle, l For the distance from the center of the round tooth to the center of the outer diameter of the rigid wheel, r _a1 is the radius of the tooth tip circle, α' is the meshing pressure angle, δ is the pinion angle of the rigid wheel, and ρ is the rim of the rigid wheel conjugate The radius, that is, the radius of the circle coincident with the tooth profile of the rigid wheel, l is the distance from the center of the toroid of the rigid wheel to the center of the outer diameter of the rigid wheel, and β is the angle of the center of the tooth of the rigid tooth, that is, the top of the wheel The angle from the center of the circle to the center line of the rigid tooth tooth, (X ₂ , Y ₂ ) is the coordinate of the motion of the center of the round tooth of the soft tooth, (X ₃ , Y ₃ ) is the coordinate of the center of the circle of the conjugate curvature of the rigid wheel, and r _a2 is soft. The radius of the tooth tip circle, (X ₄ , Y ₄ ) is the center coordinate of the top circle of the rigid tooth, r _a2 is the radius of the top circle of the soft tooth, and r _a1 is the radius of the top circle of the rigid tooth.

In the above formula,

For the tooth profile interference judgment formula, only when the coordinate of the motion circle of the center of the soft tooth tooth circle satisfies the above relationship, it means that the flexible wheel of the corresponding coordinate position does not interfere with the rigid wheel, and if the soft wheel and the rigid wheel interfere, the The coordinate position pair begins to modify the tooth width of the rigid wheel and/or the flex wheel.

In the above formula,

For the judgment formula of the tooth top circle interference, only when the coordinate of the motion of the top circle of the soft tooth tooth circle satisfies the above relationship, it means that the flexible wheel of the corresponding coordinate position does not interfere with the rigid wheel, and if the soft wheel and the rigid wheel interfere, the This coordinate position is used to modify the tooth width of the rigid wheel and/or the flex wheel.

When modifying the tooth width of the rigid wheel and/or the flexible wheel, it is necessary to simultaneously consider the tooth profile interference judgment formula and the tip circle interference judgment formula, which needs to be performed from the coordinate position of the first interference point obtained in the second formula. Retouching treatment.

For example, as shown in FIGS. 10 and 11, the three sides of the round top of the sprocket wheel are chamfered in the form of a material removal process, and the portion of the sprocket toothed groove at the opening is not modified, only for the tooth width. The portion extending from the middle to the bottom is shaped, and the amount of modification near the opening (ie, the amount of material removed and/or the depth of the shape) is small, and the amount of deformation extends to the bottom along the axis of the flex wheel. And gradually increase, after reaching the specified amount, the amount of modification remains stable. That is, as shown in Fig. 11, the right side is the direction of the opening of the flexible wheel, the left side is the bottom direction of the flexible wheel, and the amount of modification is gradually increased from right to left (from the right to the right in the upper right corner of Fig. 11) The diagonal line inclined to the left is stable after reaching a certain level (shown by the horizontal line connected to the lower end of the oblique line in Fig. 11). As shown in Fig. 12, after the modification, the rigid wheel and the flexible wheel do not interfere during the movement.

For example, as shown in FIGS. 13 and 14, the top portion of the top circle of the flex spun is subjected to a material removal treatment, and the portion of the flex spun tooth at the opening is not modified, and only extends from the middle to the bottom of the rack. The portion is subjected to the shaping treatment, and the amount of the trimming near the opening (that is, the amount of the removed material and/or the depth of the trimming) is small, and the amount of the trimming increases toward the bottom along the axis of the flex wheel, and gradually increases. After the specified amount is reached, the amount of modification remains stable. That is, as shown in Fig. 14, the right side is the direction of the opening of the flexible wheel, the left side is the bottom direction of the flexible wheel, and the amount of modification is gradually increased from right to left (from the right to the right in the upper right corner of Fig. 14) The diagonal line inclined to the left is stable after reaching a certain level (shown by the horizontal line connected to the lower end of the oblique line in Fig. 14). As shown in Fig. 15, after the modification, the rigid wheel and the flexible wheel do not interfere during the movement.

For example, as shown in FIGS. 16 and 17, the top portion of the rigid tooth tip circle is subjected to the material removal maintenance treatment, and the portion of the rigid wheel tooth groove located at the opening is not modified, and only the middle portion of the rigid wheel extends to the bottom. The portion is subjected to the shaping treatment, and the amount of the trimming near the opening (that is, the amount of material removed and/or the depth of the trimming) is small, and the amount of the trimming is gradually increased toward the bottom along the axis of the rigid wheel, After the specified amount is reached, the amount of modification remains stable. That is, as shown in FIG. 17, the right side is the direction in which the rigid wheel is located at the opening, the left side is the direction in which the rigid wheel is located at the bottom, and the amount of modification is gradually increased from right to left (from the upper right corner in FIG. 17 The diagonal line inclined from right to left) remains stable after reaching a certain level (shown by the horizontal line connected to the high end of the oblique line in Fig. 17). As shown in Fig. 18, after the modification, the rigid wheel and the flexible wheel do not interfere during the movement. Of course, there is a simple way to avoid interference, and the individual (or simultaneous) tooth width of the rigid and flexible wheels is shortened. The use of the opening to the middle section length avoids the area of the second half of the interference, which is also in accordance with the requirements of this patent.

It is disclosed above that the displacement difference of the rigid wheel and the flexible wheel affects the movement track of the flexible wheel, the negative displacement difference can provide a larger meshing range, and the meshing of the negative displacement difference at the opening is concentrated on the root of the rigid wheel. In the vicinity, as the cross section of the flexible wheel moves, the meshing zone is turned to the top of the rigid tooth due to the smaller aspect ratio of the moving track, and the interference between the top of the rigid rigid tooth is larger. If only the meshing area is considered from the opening to the center line of the flexible bearing, the tooth profile of the rigid wheel can be approximated to the trajectory of the flexible wheel on different sections by selecting the appropriate meshing pressure angle, which can form a large-area meshing result. . The meshing pressure angle is not the tool pressure angle, but the actual pressure angle of the tooth profile after machining. The same tool pressure angle will change the tooth profile due to the displacement, and the positive displacement will cause the meshing pressure angle to be larger. The negative displacement difference causes the meshing pressure angle to become small. The important influence of the meshing pressure angle on the meshing of the rigid wheel and the flexible wheel, as shown in Figs. 19 and 20, respectively, is the motion trajectory of the harmonic gear reducer with a reduction ratio of 120 at the soft wheel opening and the middle of the tooth surface. It is not difficult to see that at the opening of the flexible wheel, the top circle of the soft wheel tooth mainly meshes with the upper part of the involute tooth profile of the rigid wheel. In the middle of the tooth surface of the soft wheel, the top circle of the soft tooth tooth and the involute of the rigid wheel are mainly and a lower tooth profile engaging an addendum circle, soft tooth top circle curve trajectory height shorter, wider width, trajectory angle from the point of view, is _{_{ε 1 <α '<ε 2}} , so the closer the soft tooth surface At the bottom, the more likely it is to interfere. The harmonic gear reducer achieves the purpose of zero backlash by the preload between the rigid wheel and the flexible wheel, and the pre-pressure is derived from the wave generator, so that the flexible bearing center line to the flexible wheel opening is an effective action area. The center line of the flexible bearing is close to the middle of the tooth surface of the flexure, so the meshing range must also be considered in this area. In order to obtain more meshing range from the soft wheel opening to the middle of the soft tooth surface, it is only necessary to adjust the meshing pressure angle α' to satisfy the condition of α'≌(ε1+ε2)/2, that is, in the soft wheel. At the opening, the top circle of the soft tooth is in contact with the involute profile of the rigid wheel, and in the middle of the soft tooth, the round top of the soft tooth is in contact with the top circle of the rigid tooth to obtain a large area of engagement.

In actual use, in order to unify the outer diameter of the rigid wheel, different reduction ratios will have different displacement coefficients, so the engagement pressure angle will also change, and the corresponding tool pressure angle ranges from 22.5° to 28°.

The above description is only a preferred embodiment of the present application and a description of the principles of the applied technology. Those skilled in the art should understand that the scope of the invention referred to in the present application is not limited to the above. The technical solutions of the specific combination of the technical features are also included in other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are combined with the technical features disclosed in the present application, but are not limited to the technical features having similar functions.

Claims

A tooth type design method for a three-dimensional high-rigidity harmonic reducer, the harmonic reducer comprising a wave generator, a rigid wheel and a flexible wheel, the rigid wheel meshes with the flexible wheel, and the wave generator is in contact with the inner wall of the flexible wheel, said spline and the flexspline are involute gear, wherein the number of teeth of the circular spline is Z 1, the number of teeth of said flexspline Z 2, and Z 1 -Z 2 = 2; the The displacement coefficient of the rigid wheel is x 1 , the displacement coefficient x 2 of the flex wheel, x 1 <x 2 , and the displacement difference Δx=x 1 -x 2 ;

A material removal treatment is performed on both sides or the top of the toothed circle of the rigid wheel and/or the flexible wheel.
The tooth type design method of the three-dimensional high-rigidity harmonic reducer according to claim 1, wherein the material removal processing is performed from a middle portion to a bottom portion of the rigid wheel and/or the flexible wheel tooth width .
The tooth type design method of the three-dimensional high-rigidity harmonic reducer according to claim 1 or 2, wherein the reduction ratio of the harmonic reducer is less than or equal to 60, and the rigid wheel is formed by inserting teeth. The full height coefficient h 1 * = 1.0 to 1.3 of the rigid wheel, the pitch pitch coefficient P D1 * = 0.9 to 1.3, and the gear tooth height coefficient h * = 1.1 to 1.4 of the rigid wheel is processed, the insertion The tooth cutter tip circle radius coefficient r d1 * = 0.3 ~ 0.6, the pinion cutter root circle radius coefficient r a1 * = 0.4 ~ 1.0;

The flexible wheel is formed by hobbing, the full height coefficient h 2 * =1.1-1.4 of the flexible wheel, and the hobbing pitch pitch coefficient P D2 * =0.7-1.1 of the flexible wheel is processed. roller cutter tip radius factor r d2 * = 0.5 ~ 0.9, the rolling cutter dedendum circle radius factor r a2 * = 0.3 ~ 0.7;

The soft tooth tip clearance coefficient j 1 * = 0.1 to 0.3, the soft tooth root gap coefficient j 2 * = 0.1 to 0.4, and the meshing tooth height coefficient H w * = 0.9 to 1.2.
The tooth type design method of the three-dimensional high-rigidity harmonic reducer according to claim 1 or 2, wherein the reduction ratio of the harmonic reducer is greater than 60, and the rigid wheel is formed by inserting teeth. The full height coefficient h 1 * = 1.2 to 1.6 of the rigid wheel, the pitch pitch coefficient P D1 * = 0.9 to 1.4, and the tooth height coefficient h * = 1.1 to 1.4 of the gear shaping cutter of the rigid wheel is processed. cutter tip radius factor r d1 * = 0.2 ~ 0.6, the shaper cutter dedendum circle radius factor r a1 * = 0.6 ~ 0.9;

The flexspline is formed by hobbing, the whole depth of the flexspline coefficient h 2 * = 1.3 ~ 1.6, the pitch diameter of the roller cutter processing of the flexspline pitch coefficient P D2 * = 0.7 ~ 1.2, the The hobbing cutter tip circle radius coefficient r d2 * = 0.5 ~ 0.8, the hobbing cutter root circle radius coefficient r a2 * = 0.4 ~ 0.8;

The soft tooth tip clearance coefficient j 1 * = 0.1 to 0.3, the soft tooth root gap coefficient j 2 * = 0.2 to 0.5, and the meshing tooth height coefficient H w * = 1.0 to 1.3.
The tooth type design method of the three-dimensional high-rigidity harmonic reducer according to claim 1 or 2, wherein the interference between the rigid wheel and the flexible wheel is obtained according to the following relation Starting position, and at least starting from the interference starting position, performing the material removal modification process on the rigid wheel and/or the bottom of the flexible wheel;

X 3 =-r b1 ·sin(α'-δ);

Y 3 =r b1 ·cos(α'-δ);

l=d a1 /2-j 2 +r a1 ;

X 4 = l·cosβ;

Y 4 = l · sinβ;

Where d w1 is the rigid wheel meshing pitch diameter, α' is the meshing pressure angle, α is the tool pressure angle, T is the reduction ratio, r b1 is the rigid wheel base circle radius, δ is the rigid wheel tooth profile declination, d a1 is The outer diameter of the rigid wheel, j 2 is the root pitch of the soft gear, r a1 is the radius of the top circle of the rigid wheel, r b1 is the radius of the base circle of the rigid wheel, and l is the distance from the center of the round tooth to the center of the outer diameter of the rigid wheel. r a1 is the radius of the tooth tip circle, α' is the meshing pressure angle, δ is the pinion angle of the rigid wheel, ρ is the radius of the conjugate curvature circle of the rigid wheel, and l is the center of the round tooth to the outer diameter of the outer diameter of the rigid wheel The distance is β, which is the center angle of the crown of the rigid tooth, and (X 2 , Y 2 ) is the coordinate of the motion of the center of the round tooth of the soft tooth. (X 3 , Y 3 ) is the coordinate of the center of the circle of the conjugate curvature of the rigid wheel, r A2 is the radius of the top circle of the soft tooth, (X 4 , Y 4 ) is the center coordinate of the top circle of the rigid tooth, r a2 is the radius of the top circle of the soft tooth, and r a1 is the radius of the top circle of the rigid tooth.
The tooth form design method of the three-dimensional high-rigidity harmonic reducer according to claim 5, wherein the tool pressure angle α ranges from 22.5° to 28°.
A tooth type design method for a three-dimensional high-rigidity harmonic reducer according to claim 5, wherein

Where ε 1 is the trajectory angle at the opening of the flex wheel, and ε 2 is the trajectory angle at the middle of the flex wheel.