WO2021098412A1

WO2021098412A1 - Gear-pin dual-mode meshing small-tooth-difference planetary gear pair and precision speed reducer

Info

Publication number: WO2021098412A1
Application number: PCT/CN2020/120743
Authority: WO
Inventors: 李轩; 李伟达; 黄剑斌; 杨杰; 孙立宁
Original assignee: 苏州大学
Priority date: 2019-11-20
Filing date: 2020-10-14
Publication date: 2021-05-27
Also published as: CN110966355B; CN110966355A

Abstract

The present invention relates to a gear-pin dual-mode meshing small-tooth-difference planetary gear pair and a precision speed reducer. The gear-pin dual-mode meshing small-tooth-difference planetary gear pair comprises an inner gear and a plurality of outer gears; the inner gear is provided with a first arc containing groove and a first curve tooth profile; the outer gears are provided with second arc containing grooves and second curve tooth profiles; a first roller pin is arranged in the first arc containing groove; second roller pins are arranged in the second arc containing grooves; and a meshing process of the inner gear and the outer gears comprises meshing of the first roller pin and the second curved tooth profiles, meshing of the first roller pin and the second roller pins, and meshing of the first curved tooth profile and the second roller pins. The present invention has the characteristics of multiple teeth, multiple points and rolling contact; gear tooth loads can be reduced; a dynamic pressure oil film is formed; the error homogenization effect is significant; and the bearing capacity, the transmission efficiency and the transmission precision of the reducer can be improved.

Description

Gear-needle dual-mode meshing planetary gear pair with small tooth difference and precision reducer

Technical field

The invention relates to the technical field of precision transmission, in particular to a planetary gear pair and a precision reducer with a tooth-pin dual-mode meshing small tooth difference planetary gear pair.

Background technique

With the development of machinery in the direction of high efficiency, precision and multi-function, higher requirements are put forward for the function and performance of gear transmission. For example, the precision cycloid reducer used in the field of industrial robots requires excellent characteristics such as high load-bearing capacity, high precision, and high rigidity. At present, my country's precision cycloid reducer is heavily dependent on imports and is monopolized by Japanese companies. Although domestic enterprises have invested a lot of material and financial resources in the development of the precision reducer, with high-end machine tools and advanced equipment, the machining ability can obtain high machining accuracy, and the system errors of the reducer have been eliminated, but there is still random processing. Errors result in a big gap between products in terms of accuracy retention, service life and production costs compared with foreign countries.

In order to overcome the above-mentioned problems, the existing Chinese invention patent (CN108843746A) discloses a precision reducer for robots, including a decelerating part, the decelerating part includes: an eccentric wheel, a cycloid wheel, and a needle gear; the pendulum The thread wheel includes: a first cycloidal wheel and a second cycloidal wheel arranged side by side; the needle gear includes: a needle gear housing, needle teeth arranged in the needle gear housing, and an outer ring fixed on the needle gear housing A bearing equipped with the needle teeth, the inner ring of the bearing is sleeved in the middle of the needle teeth, the needle teeth are arranged around the inner circumferential wall of the needle tooth shell to form a ring needle tooth group, the first cycloid and the second The cycloidal wheel meshes with the two ends of the needle teeth respectively. The above-mentioned needle gear is supported by the bearing and the cycloidal gear is rolling transmission, which reduces the wear of the cycloidal gear and the needle gear transmission. Although the service life of the cycloidal gear reducer is improved, the eccentric shaft has an eccentric phase and high-precision machining. The technical problem is high, the production cost is high, and the accuracy is not easy to guarantee.

Summary of the invention

For this reason, the technical problem to be solved by the present invention is to overcome the problems of poor reliability, difficult processing, and high cost in the prior art, thereby providing a high-performance, high-precision and economically-processed double-die meshing planetary gear with small tooth difference. Vice and precision reducer.

In order to solve the above technical problems, a tooth-pin dual-mode meshing planetary gear pair with a small tooth difference of the present invention includes an internal gear and a plurality of external gears. The internal gear is provided with a first arc containing groove and a first curved tooth. The external gear is provided with a second arc containing groove and a second curved tooth profile, wherein the first arc containing groove is provided with a first needle roller, and the second arc containing groove is provided with The second needle roller, during the meshing process of the internal gear and the external gear, includes the meshing of the first needle roller and the second curved tooth profile, the first needle roller and the second roller The meshing of the needle and the meshing of the first curved tooth profile and the second needle roller.

In an embodiment of the present invention, for the curved tooth profile Σ(x ₁ , y ₁ ) of the internal gear, the tooth profile equation is:

among them,

They are the rotation angle of the internal gear and the external gear respectively, θ is the variable of the arc angle of the needle roller, z ₁ is the number of teeth of the internal gear, r ₂ is the second needle roller radius in the second arc containing groove, e is the crank shaft eccentricity, R ₂ is the index circle radius of the second needle roller in the second arc containing groove,

It is the meshing limit value.

In an embodiment of the present invention, for the curved tooth profile Γ(x ₂ , y ₂ ) of the external gear, the tooth profile equation is:

Among them, φ ₁ and φ ₂ are the rotation angle of the internal gear and the rotation angle of the external gear, respectively, and z ₂ is the number of teeth of the external gear.

In an embodiment of the present invention, the first needle roller radius r ₁ and the index circle radius R ₁ in the first arc containing groove are obtained by the following steps: determine the external gear according to the structural size and transmission ratio of the transmission device The number of teeth z ₁ , the number of teeth z _{2 of the} internal gear, and the second needle roller radius r _{2 in the} second circular arc containment groove, and the indexing circle radius R _{2 are used} to preliminarily determine the initial value of the eccentricity e; The law of motion, the curve tooth profile equation ∑(x ₁ , y ₁ ) of the internal gear and the curve tooth profile equation Γ(x ₂ , y ₂ ) of the external gear are calculated by the envelope method; the curve tooth profile equation of the internal gear ∑ (x ₁ ,y ₁ ) in

Fit function

Solve the problem, get the first needle roller radius r ₁ and the first needle roller center coordinates (x ₀ , y ₀ ) in the first arc containing groove, where (x _1i , y _1i ) are the internal gear tooth profile coordinates, n is the number of data points; calculate the fitting gap

Judge the size of the fitting gap and the design gap C ₀ , if 0＜C≤C ₀ , then the design parameters of this group meet the design requirements, determine the design parameters R ₁ =y ₀ , r ₁ , and end the design process; otherwise, you need to change Optimize the parameter eccentricity e and external gear index circle radius R ₂ , and recalculate until the design requirements are met.

In an embodiment of the present invention, the external gear includes a first external gear and a second external gear, the first external gear and the second external gear are arranged in a phase of 180°, and the first external gear and the second external gear A needle roller isolation retaining ring is arranged between the two external gears.

The present invention also provides a precision reducer, including the pinion-tooth dual-mode meshing planetary gear pair with small tooth difference, a combined double eccentric crankshaft, an involute planetary gear and a sun gear shaft as described in any one of the above, wherein The combined double eccentric crankshaft is equipped with an external gear of the toothed pin double-mode meshing with a planetary gear pair with a small tooth difference, the combined double eccentric crankshaft includes a spline shaft, and the involute planetary gear is mounted on the On the spline shaft, the sun gear shaft is located at the center of the precision reducer, and the involute planetary gear meshes with the sun gear shaft.

In an embodiment of the present invention, the combined double eccentric crankshaft further includes a first inner spline sleeve, a second inner spline sleeve, a first inner spline eccentric sleeve, and a second inner spline eccentric sleeve , Wherein the first inner spline sleeve, the second inner spline sleeve, the first inner spline eccentric sleeve, and the second inner spline eccentric sleeve are all installed on the spline shaft, and the combined type The double eccentric crankshaft is supported on the planet carrier.

In an embodiment of the present invention, the first internal spline eccentric sleeve and the second internal spline eccentric sleeve are arranged in a 180° phase arrangement, and both have an even number of teeth with the spline shaft, and the first The outer circles of the inner spline eccentric sleeve and the second inner spline eccentric sleeve are both bearing raceways with single ribs.

In an embodiment of the present invention, the planet carrier includes a first end disc and a second end disc, and the first end disc and the second end disc are supported inside the internal gear.

In an embodiment of the present invention, the involute planetary gear has internal splines, which have the same number of teeth as the spline shaft and are used in cooperation.

Compared with the prior art, the above-mentioned technical solution of the present invention has the following advantages:

The tooth-pin dual-mode meshing planetary gear pair and precision reducer of the present invention includes an internal gear and a plurality of external gears. The internal gear is provided with a first arc containing groove and a first curved tooth profile, The external gear is provided with a second circular arc containing groove and a second curved tooth profile, wherein the first circular arc containing groove is provided with a first needle roller, and the second circular arc containing groove is provided with a second Needle rollers. During the meshing process of the internal gear and the external gear, the meshing of the first needle roller and the second curved tooth profile, the meshing of the first needle roller and the second needle roller The meshing and the meshing between the second needle roller and the first curved tooth profile form a "needle roller-needle" and "tooth profile-needle" dual-mode meshing gear pair, because the gear pair has multiple teeth The advantages of simultaneous contact, multi-point meshing on a single tooth, rolling contact with needles, etc., are beneficial to improve and reduce the meshing force on the gear, form a dynamic pressure oil film, and help improve the load-bearing capacity and transmission efficiency of the reducer; in addition, the The contact deformation and movement wear of the gear pair under the action of the load will make all the tooth profile random errors approach the error average value, the error averaging effect is obvious, and the transmission accuracy is high; in addition, the rollers with different machining accuracy can be selected. The needle adjusts the meshing gap, so there is no need to modify the tooth profile.

Description of the drawings

In order to make the content of the present invention easier to be understood clearly, the following further describes the present invention in detail according to specific embodiments of the present invention and in conjunction with the accompanying drawings.

Figure 1 is a schematic diagram of a planetary gear pair with a small tooth difference between the tooth-pin dual-mode meshing of the present invention;

Figure 2 is a partial enlarged view of the "tooth profile-needle" meshing of the present invention;

Figure 3 is a partial enlarged view of the "needle-needle-roller" tooth top meshing of the present invention;

Figure 4 is a partial enlarged view of the tooth side meshing of the "needle-needle roller" of the present invention;

Figure 5 is an assembly diagram of the precision reducer of the present invention;

Figure 6 is a cross-sectional view of the precision reducer of the present invention;

Figure 7 is a schematic diagram of the combined double eccentric crankshaft of the present invention;

Figure 8 is a schematic diagram of the spline shaft of the present invention;

Figure 9 is a perspective view of the inner spline eccentric sleeve of the present invention;

Fig. 10 is a front view of the inner spline eccentric sleeve of the present invention.

Description of reference signs in the specification: 10-internal gear, 11-first arc containing groove, 12-first curved tooth profile, 13-first needle roller, 20-external gear, 20A-first external gear, 20B-th Two external gears, 21-second arc containment groove, 22-second curved tooth profile, 23-second needle roller, 24-needle roller spacer ring, 30-combined double eccentric crankshaft, 31-spline shaft , 32A-first inner spline bushing, 32B-second inner spline bushing, 33A-first inner spline eccentric bushing, 33B-second inner spline eccentric bushing, 330-phase mark hole, 331-bearing Raceway, 34A-first circlip, 34B-second circlip, 34C-sleeve, 40-involute planetary gear, 50-sun gear shaft, 60A-first end disc, 60B-second end Disc, 71A-first cylindrical roller bearing, 71B-second cylindrical roller bearing, 72A-first tapered roller bearing, 72B-second tapered roller bearing, 73A-first bearing, 73B-second bearing, 74-Oil seal.

Detailed ways

Example one

As shown in Figure 1, Figure 2, Figure 3, and Figure 4, this embodiment provides a pinion double-mode meshing planetary gear pair with a small tooth difference, including an internal gear 10 and a plurality of external gears 20. The internal gear 10 is A first arc containing groove 11 and a first curved tooth profile 12 are provided. The external gear 20 is provided with a second arc containing groove 21 and a second curved tooth profile 22, wherein the first arc containing groove 11 A first roller needle 13 is provided inside, a second roller needle 23 is provided in the second arc containing groove 21, and the internal gear 10 and the external gear 11 include the first roller during the meshing process. The meshing of the needle 13 and the second curved tooth profile 22, the meshing of the first needle 13 and the second needle roller 23, and the meshing of the first curved tooth profile 12 and the second needle 23 Meshing.

The tooth-pin dual-mode meshing planetary gear pair with small tooth difference in this embodiment includes an internal gear 10 and a plurality of external gears 20. The internal gear 10 is provided with a first arc containing groove 11 and a first curved tooth profile. 12. The external gear 20 is provided with a second circular arc containing groove 21 and a second curved tooth profile 22, wherein the first circular arc containing groove 11 is provided with a first roller needle 13, and the second circular arc A second needle roller 23 is provided in the containing groove 21. During the meshing process of the internal gear 10 and the external gear 11, the meshing process of the first needle roller 13 and the second curved tooth profile 22 is included. The meshing of the first needle roller 13 and the second needle roller 23, and the meshing of the first curved tooth profile 12 and the tooth side of the second needle roller 23, form "needle roller-needle roller" and "tooth roller". Profile-needle" dual-mode meshing gear pair, because the gear pair has the advantages of multi-tooth simultaneous contact, multi-point meshing on a single tooth, rolling contact with needles, etc., which is beneficial to improve and reduce the meshing force on the gear and form a dynamic The oil pressure film is beneficial to improve the load-carrying capacity and transmission efficiency of the reducer; in addition, the contact deformation and motion wear of the gear pair under load make the random error of all tooth profiles close to the average error, and the error is equalized The effect is obvious and the transmission accuracy is high; in addition, the meshing gap can be adjusted by selecting rollers with different machining accuracy, so there is no need to modify the tooth profile.

In order to achieve the tooth-pin dual-mode meshing, the curve tooth profile Σ(x ₁ , y ₁ ) of the internal gear 10 has the tooth profile equation:

among them,

They are the internal gear 10 rotation angle and the external gear 20 rotation angle, θ is the variable of the arc angle of the needle roller, z ₁ is the number of teeth of the internal gear, r ₂ is the radius of the second needle 23 in the second arc containing groove 21, and e is the crankshaft Eccentricity, R ₂ is the index circle radius of the second needle roller 23 in the second arc containing groove 21,

It is the meshing limit value.

For the curved tooth profile Γ(x ₂ , y ₂ ) of the external gear 20, the tooth profile equation is:

Among them, φ ₁ and φ ₂ are the rotation angle of the internal gear 10 and the rotation angle of the external gear 20, and z ₂ is the number of teeth of the external gear 20.

_{In addition, the radius r 1} and the index circle radius R ₁ of the first needle roller 13 in the first arc containing groove 11 are obtained by the following steps:

Step S1: The transmission frame size, transmission ratio, determining the number of teeth of the external gear 20 z _1, the number of teeth of the internal gear 10 and a second needle z ₂ second arcuate groove 21 is 23 inclusive radius r _2, the pitch circle Radius R ₂ , initially determine the initial value of eccentricity e;

Step S2: According to the law of relative motion between the internal gear 10 and the external gear 20, the curve tooth profile equation ∑(x ₁ , y ₁ ) of the internal gear 10 and the curve tooth profile equation Γ(x ₂ ,y ₂ );

Step S3: For the curve tooth profile equation ∑(x ₁ , y ₁ ) of the internal gear 10

Fit function

_{Solve the problem and obtain the radius r 1} of the first needle roller 13 and the center coordinates (x ₀ , y ₀ ) of the first needle roller 13 in the first arc containing groove 11, where (x _1i , y _1i ) is the internal gear with 10 teeth Profile coordinate value, n is the number of data points;

Step S4: Calculate the fitting gap

Step S5: Determine the size of the fitting gap and the design gap C _0. _{If 0 <C ≤ C 0} , then the set of design parameters meet the design requirements, determine the design parameters R ₁ =y ₀ , r ₁ , and end the design process; otherwise, It is necessary to change the optimized parameter eccentricity e and the 20 indexing circle radius R _{2 of the} external gear, and recalculate until the design requirements are met.

In order to ensure stable output and stable operation of the entire device, the external gear 20 includes a first external gear 20A and a second external gear 20B, and the first external gear 20A and the second external gear 20B are arranged in a 180° phase; In order to prevent two adjacent needle rollers from moving in the axial direction, a needle roller spacer 24 is arranged between the first external gear 20A and the second external gear 20B, so as to ensure the axial positioning.

Example two

As shown in Figures 5 and 6 and Figures 7 and 8, this embodiment provides a precision reducer, including the pinion-tooth dual-mode meshing planetary gear pair with small tooth difference and the combined double-eccentric crankshaft described in the first embodiment. 30. The involute planetary gear 40 and the sun gear shaft 50, wherein the combined double eccentric crankshaft 30 is mounted on the external gear 20 of the toothed pin double-mode meshing planetary gear pair with a small tooth difference, and the combined double eccentric The crankshaft 30 includes a spline shaft 31, the involute planetary gear 40 is mounted on the spline shaft 31, the sun gear shaft 50 is located at the center of the precision reducer, and the involute planetary gear 40 meshes with the sun gear shaft 50.

The precision reducer described in this embodiment includes the pinion-tooth dual-mode meshing planetary gear pair with small tooth difference, the combined double eccentric crankshaft 30, the involute planetary gear 40 and the sun gear shaft 50 described in the first embodiment. The combined double-eccentric crankshaft 30 is equipped with the external gear 20 of the toothed pin double-mode meshing planetary gear pair with a small tooth difference, the combined double-eccentric crankshaft 30 includes a spline shaft 31, the involute planet The gear 40 is mounted on the spline shaft 31, the sun gear shaft 50 is located in the center of the precision reducer, and the involute planetary gear 40 meshes with the sun gear shaft 50 to realize the first-stage reduction , The second-stage deceleration is achieved through the tooth-needle dual-mode meshing planetary gear pair with a small tooth difference and finally the power is output, so as to achieve the purpose of deceleration. The present invention adopts "needle roller-needle" and "tooth profile-needle roller". "Dual-mode meshing gear pair, so while realizing deceleration, it also has all the advantages contained in the first embodiment.

As shown in Figure 7, the combined double eccentric crankshaft 30 also includes a first inner spline sleeve 32A, a second inner spline sleeve 32B, a first inner spline eccentric sleeve 33A, and a second inner spline eccentric sleeve. Sleeve 33B, wherein the first inner spline sleeve 31A, the second inner spline sleeve 32B, the first inner spline eccentric sleeve 33A, and the second inner spline eccentric sleeve 33B are all installed on the spline shaft 31 Above, and the combined double eccentric crankshaft 30 is supported on the planet carrier, thereby helping to solve the problem of high-precision machining of the crankshaft eccentric phase, not only the machining process is simple, the precision is high, and the machining accuracy is better.

As shown in Figures 9 and 10, the first internal spline eccentric sleeve 33A and the second internal spline eccentric sleeve 33B are arranged in a phase of 180° and are processed with a phase marking hole 330, and are connected to the spline shaft 31 have even-numbered teeth, so as to solve the problem of high-precision machining of the crank shaft eccentric phase; the outer circles of the first inner spline eccentric sleeve 33A and the second inner spline eccentric sleeve 33B are bearing rollers with single ribs Road 331 not only has simple processing technology and high precision, but also has better processing accuracy. In addition, the spline shaft 31 is further provided with a first elastic retaining ring 34A, a second elastic retaining ring 34B, and a sleeve 34C. The first elastic retaining ring 34A and the sleeve 34C can be used to position the gradually The open-line planetary gear 40 can position the first inner spline sleeve 32A, the second inner spline sleeve 32B, the first inner spline eccentric sleeve 33A, and the first inner spline sleeve 34C through the second elastic retaining ring 34B and the sleeve 34C. The second internal spline eccentric sleeve 33B. In addition, the involute planetary gear 40 has internal splines, and the number of teeth is equal to and used in conjunction with the spline shaft 31, so as to help ensure the smooth operation of the entire device.

In order to ensure stable output and stable operation of the entire device, the external gear 20 includes a first external gear 20A and a second external gear 20B, and the first external gear 20A and the second external gear 20B are arranged in a 180° phase; The first external gear 20A and the first external gear 20B are evenly distributed with two or three coordinate holes to facilitate positioning, and pass through the first cylindrical roller bearing 71A, the second cylindrical roller bearing 71B and the combined double The eccentric crankshaft 30 is matched, and the combined double eccentric crankshaft 30 is supported in the planet carrier through the first tapered roller bearing 74A and the second tapered roller bearing 74B. Specifically, the first cylindrical roller bearing 71A is mounted on the first internal spline eccentric sleeve 33A, the first external gear 20A is mounted on the first cylindrical roller bearing 71A, and the first tapered roller The sub-bearing 74A is installed on the first inner spline sleeve 32A, the first tapered roller bearing 74A is fixed on the planet carrier; the second cylindrical roller bearing 71B is installed on the second inner The spline eccentric sleeve 33B, the second external gear 20B is mounted on the second cylindrical roller bearing 71B, the second tapered roller bearing 74B is mounted on the second inner spline sleeve 32B, the The second tapered roller bearing 74B is fixed on the planet carrier, thereby ensuring the stability of power transmission.

The planet carrier includes a first end disc 60A and a second end disc 60B, and the first end disc 60A and the second end disc 60B are supported inside the internal gear 10. Specifically, the first end disc 60A and the second end disc 60B are supported inside the internal gear 10 through a first bearing 73A and a second bearing 73B, respectively, and are sealed by an oil seal 74. Specifically, the first end disk 60A is mounted on the first bearing 73A, and the second end disk 60B is mounted on the second bearing 73B.

In the precision reducer of this embodiment, each of the involute planetary gears 40 meshes with the sun gear shaft 50, and the rotation of the sun gear shaft 50 drives the movement of the involute planetary gears 40 to achieve In the first stage of speed reduction, the involute planetary gear 40 is mounted on the spline shaft 31 of the combined double eccentric crankshaft 30, and the movement of the involute planetary gear 40 drives the combined double eccentric crankshaft 30 movement, the first external gear 20A of the pinion double-mode meshing planetary gear pair with small tooth difference passes through the first cylindrical roller bearing 71A and the second external gear 20B through the second cylindrical roller bearing 71B and The combined double eccentric crankshaft 30 cooperates to drive the movement of the external gear 20, so as to achieve the second-stage deceleration through the tooth-pin double-mode meshing of the planetary gear pair with small tooth difference, and finally through the first end plate The planetary carrier composed of 60A and the second end plate 60B will output the power.

Obviously, the foregoing embodiments are merely examples for clear description, and are not intended to limit the implementation manners. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is unnecessary and impossible to list all the implementation methods here. The obvious changes or changes derived from this are still within the protection scope created by the present invention.

Claims

A tooth-pin dual-mode meshing planetary gear pair with small tooth difference, comprising an internal gear and a plurality of external gears, characterized in that: the internal gear is provided with a first arc containing groove and a first curved tooth profile, and the external gear The gear is provided with a second circular arc containing groove and a second curved tooth profile, wherein the first circular arc containing groove is provided with a first needle roller, and the second circular arc containing groove is provided with a second needle roller, The meshing process of the internal gear and the external gear includes the meshing of the first needle roller and the second curved tooth profile, the meshing of the first needle roller and the second needle roller, and The meshing of the first curved tooth profile and the second needle roller.
The tooth-pin dual-mode meshing planetary gear pair with small tooth difference according to claim 1, characterized in that the curve tooth profile Σ(x 1 , y 1 ) of the internal gear, the tooth profile equation is:

among them,
They are the rotation angle of the internal gear and the rotation angle of the external gear, θ is the variable of the arc angle of the needle roller, z 1 is the number of teeth of the internal gear, r 2 is the second needle roller radius in the second arc containing groove, and e is the crank shaft eccentricity. , R 2 is the index circle radius of the second needle roller in the second arc containing groove,
It is the meshing limit value.
The tooth-pin dual-mode meshing planetary gear pair with small tooth difference according to claim 1, characterized in that: the curve tooth profile Γ(x 2 , y 2 ) of the external gear, the tooth profile equation is:

Among them, φ 1 and φ 2 are the rotation angle of the internal gear and the rotation angle of the external gear, respectively, and z 2 is the number of teeth of the external gear.
The tooth-pin dual-mode meshing small tooth difference planetary gear pair according to claim 1, characterized in that: the first needle roller radius r 1 and the index circle radius R 1 in the first arc containing groove are determined by the following steps obtain:

Step S1: Determine the number of teeth z 1 of the external gear, the number of teeth z 2 of the internal gear, and the second needle roller radius r 2 and the indexing circle radius R 2 in the second arc containing groove according to the structural size and transmission ratio of the transmission device, Preliminarily determine the initial value of the eccentricity e;

Step S2: According to the relative motion law of the internal gear and the external gear, the curve tooth profile equation Σ(x 1 , y 1 ) of the internal gear and the curve tooth profile equation Γ(x 2 , y 2) of the external gear are calculated by the envelope method );

Step S3: The curve tooth profile equation Σ(x 1 , y 1 ) of the internal gear is
Fit function
Solve the problem, get the first needle roller radius r 1 and the first needle roller center coordinates (x 0 , y 0 ) in the first arc containing groove, where (x 1i , y 1i ) are the internal gear tooth profile coordinates, n is the number of data points;

Step S4: Calculate the fitting gap

Step S5: Determine the size of the fitting gap and the design gap C 0. If 0 <C ≤ C 0 , then the set of design parameters meet the design requirements, determine the design parameters R 1 =y 0 , r 1 , and end the design process; otherwise, It is necessary to change the optimized parameters eccentricity e, the external gear indexing circle radius R 2 , and recalculate until the design requirements are met.
The tooth-pin dual-mode meshing planetary gear pair with small tooth difference according to claim 1, wherein the external gear includes a first external gear and a second external gear, and the first external gear and the second external gear form The phase arrangement is 180°, and a needle roller isolation retainer ring is arranged between the first external gear and the second external gear.
A precision reducer, characterized in that it comprises the tooth-pin dual-mode meshing planetary gear pair with a small tooth difference according to any one of claims 1-5, a combined double-eccentric crankshaft, an involute planetary gear and a sun gear Shaft, wherein the combined double eccentric crankshaft is mounted on the external gear of the toothed pin double mode to engage a planetary gear pair with a small tooth difference, the combined double eccentric crankshaft includes a spline shaft, and the involute planetary gear Installed on the spline shaft, the sun gear shaft is located at the center of the precision reducer, and the involute planetary gear meshes with the sun gear shaft.
The precision reducer according to claim 6, characterized in that: the combined double eccentric crankshaft further comprises a first inner spline bushing, a second inner spline bushing, a first inner spline eccentric bushing, and a second inner spline bushing. Two internal spline eccentric sleeves, wherein the first internal spline sleeve, the second internal spline sleeve, the first internal spline eccentric sleeve, and the second internal spline eccentric sleeve are all mounted on the spline shaft , And the combined double eccentric crankshaft is supported on the planet carrier.
The precision reducer according to claim 7, characterized in that: the first internal spline eccentric sleeve and the second internal spline eccentric sleeve are arranged in a 180° phase arrangement, and both have an even number with the spline shaft. For the teeth, the outer circles of the first internal spline eccentric sleeve and the second internal spline eccentric sleeve are both bearing raceways with single ribs.
The precision reducer according to claim 7, wherein the planet carrier includes a first end disc and a second end disc, and the first end disc and the second end disc are supported on the internal gear internal.
The precision reducer according to claim 6, wherein the involute planetary gear has internal splines, and the number of teeth is equal to the spline shaft and used in cooperation.