WO2020238075A1

WO2020238075A1 - Double-arc gapped meshing small-tooth-difference planetary transmission device

Info

Publication number: WO2020238075A1
Application number: PCT/CN2019/119448
Authority: WO
Inventors: 李伟达; 李轩; 杨杰
Original assignee: 苏州博安捷机器人科技有限公司
Priority date: 2019-05-29
Filing date: 2019-11-19
Publication date: 2020-12-03
Also published as: CN110067833A; CN110067833B

Abstract

Provided is a double-arc gapped meshing small-tooth-difference planetary transmission device, comprising: a box body and an eccentric shaft (1) arranged in the box body, wherein a first eccentric part (2) and a second eccentric part (3) of the eccentric shaft are respectively provided with two outer gears (4); and an inner gear (6) is arranged on the inner wall of the box body corresponding to the outer gear, the inner gear being meshed with the outer gears in a matched mode, a plurality of driving pins (7) being further arranged between the two outer gears, two ends of each driving pin being connected and matched with two end discs (9) to form a planetary carrier structure and output power, the tooth profile of the inner gear and the tooth profile of each outer gear being both arcs, and an initial meshing gap existing between the inner gear and each outer gear. Thus, the problems of complex curve high-precision machining and tooth profile modification are solved, and a good precision operation effect is maintained.

Description

Planetary transmission device with double circular arcs with clearance meshing and small tooth difference

Technical field

The invention relates to the technical field of gear transmissions, in particular to a planetary transmission device with double circular arcs with clearance meshing and less tooth difference

Background technique

Due to the advantages of large transmission ratio, compact structure, large carrying capacity and high transmission efficiency, planetary transmission with small tooth difference has been widely used in power transmission fields such as metallurgy, mining and chemical industry. Due to the large number of meshing teeth, this transmission has obvious error averaging effect. In recent years, it has received more and more attention in precision transmission fields such as robots, aerospace and CNC machine tools.

The existing implementation schemes include cycloidal pin wheel few tooth difference planetary transmission, involute few tooth difference planetary transmission and so on.

The tooth profiles of the conjugate gears of the existing planetary transmission with small tooth difference are complex curves such as involutes and involutes, cycloids and arcs, resulting in relatively complicated manufacturing and difficult to ensure accuracy, especially the processing of cycloids. Generally, it needs to be carried out on special machine tools. The processing cost is high, and it is difficult to match the design curve with the processed curve. This high-precision modification method was once controlled by foreign companies.

Summary of the invention

The technical problem to be solved by the present invention is to provide a planetary transmission device with double-arc gap meshing and small tooth difference, which solves the problems of high-precision machining of complex curves and tooth profile modification, and maintains a good precision operation effect.

In order to solve the above technical problems, the present invention provides a double-arc gap meshing planetary transmission device with small tooth difference, comprising a box body and an eccentric shaft arranged in the box body, a first eccentric part and a second eccentric shaft of the eccentric shaft Two external gears are respectively provided on the parts, internal gears are provided on the inner wall of the box corresponding to the external gears, and the internal gears mesh with the external gears. A plurality of driving pins are also provided between the two external gears. Both ends of the driving pin are connected with the two end plates to form a planet carrier structure and output power. The tooth profile of the internal gear and the external gear are both arcs, and there is an initial meshing gap between the internal gear and the external gear.

Further, both the internal gear and the external gear have gear teeth with arc-shaped tooth profiles.

Further, the tooth profile of the internal gear is obtained by an inner roller needle arranged on the tooth portion, the inner roller is provided with a containing groove on the corresponding tooth portion, and the outer gear has an arc-shaped tooth profile. Gear teeth.

Further, the tooth profile of the external gear is obtained by an outer roller needle arranged on the tooth portion, the outer roller is provided with a containing groove on the corresponding tooth portion, and the inner gear has a circular arc tooth profile. Gear teeth.

Further, the tooth profile of the internal gear is obtained by an inner roller needle arranged on the tooth part, the inner roller is provided with a containing groove on the corresponding tooth part, and the tooth profile of the external gear is set by The outer roller needle on the tooth is obtained, and the outer roller is provided with a containing groove on the corresponding tooth.

Further, the box body is also provided with a needle roller limit retaining ring.

A method for forming a double-arc gap meshing gear pair includes the following steps:

Step 1) Determine the number of teeth of the external gear z ₁ , the number of teeth of the internal gear z ₂ and the arc radius of the external gear tooth profile r _o according to the structural size and transmission ratio of the transmission device, and preliminarily determine the eccentricity e and the index circle radius of the external gear R _o Range and initial value;

The arc tooth profile equation of the external gear is:

Among them, θ is the arc angle variable;

Step 2) According to the relative motion law of the internal gear and the external gear, use the arc of the external gear tooth profile to envelop the conjugate tooth profile curve of the internal gear to determine the internal gear conjugate tooth profile equation f(x ₂ ,y ₂ ) And the meshing equation Φ, the conjugate tooth profile equation is obtained as follows:

among them,

They are the rotation angles of internal and external gears, λ = ez ₁ /R _o ;

Step 3) Calculate the meshing limit function Φ _{t of the} internal gear tooth profile and solve the meshing limit value θ _t simultaneously with the meshing equation. The equations can be as follows:

The solution is available, the meshing limit value

Step 4) Fit the function in the range of [-θ _t ,θ _t ]

Solve to obtain the single-tooth arc profile radius r _i and the center coordinates (x _c , y _c ) of the internal gear;

Among them, (x _2j ,y _2j ) is the coordinate value of the conjugate tooth profile of the internal gear, and n is the number of data points;

Step 5) Calculate the fitting gap

Step 6) Determine the size of the fitting gap and the initial meshing gap limit value c _0. If 0 <c _i ≤ c ₀ , then the set of design parameters meets the design requirements, determine the design parameters R _i and r _i , and end the design process, and vice versa , You need to change the optimized parameters eccentricity e, external gear indexing circle radius _Ro , and recalculate until the design requirements are met.

The beneficial effects of the present invention:

1. The double-arc tooth profile meshing can avoid the processing of complex curves, and the arc processing is less difficult; the processing technology is simple and the precision is high, and it has better processing economic precision.

2. The backlash meshing gear pair is equivalently obtained by the conjugate meshing tooth profile, and the meshing running state is good; at the same time, the number of meshing teeth is large, the meshing range is large, and the bearing capacity is high; the error equalization effect is obvious, which can reduce the transmission error and improve the transmission accuracy .

3. This method first calculates the arc tooth profile of the external gear, and derives the meshing conjugate tooth profile, arc tooth profile, tooth profile radius, and circle parameters of the internal gear according to the arc tooth profile of the external gear. The transmission device does not need to be modified later, and the gap can be ensured and effectively controlled during design.

4. The transmission device adopts a simple support structure to withstand large external axial force and radial force, and can achieve coaxial dual output; it adopts oil seal for complete sealing, ensuring good lubrication conditions.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of the present invention;

Figure 2 is an exploded schematic diagram of part of the structure of the present invention;

Figure 3 is a schematic diagram of the gear pair meshing of the present invention;

Figure 4 is a schematic diagram of the head gap in Figure 3 of the present invention;

Figure 5 is a schematic diagram of the bottom gap in Figure 3 of the present invention;

Figure 6 is a schematic diagram of the side gap in Figure 3 of the present invention;

Fig. 7 is a schematic diagram of equivalent conjugate meshing of the gear pair in Fig. 3 of the present invention;

Figure 8 is a schematic diagram of the integral gear tooth structure of the present invention;

Figure 9 is a schematic diagram of the head gap in Figure 8 of the present invention;

Figure 10 is a schematic diagram of the bottom gap in Figure 8 of the present invention;

Figure 11 is a schematic diagram of the side gap in Figure 8 of the present invention;

Figure 12 is a schematic structural view of the present invention with an inner needle roller;

Figure 13 is a schematic diagram of the head gap in Figure 12 of the present invention;

Figure 14 is a schematic diagram of the bottom gap in Figure 12 of the present invention;

Figure 15 is a schematic diagram of the side gap in Figure 12 of the present invention;

Figure 16 is a schematic view of the structure of the present invention with external needle rollers;

Figure 17 is a schematic diagram of the head gap in Figure 16 of the present invention;

Figure 18 is a schematic diagram of the bottom gap in Figure 16 of the present invention;

Figure 19 is a schematic diagram of the side gap in Figure 16 of the present invention;

Fig. 20 is a flow chart of the formation of the double-arc gapped meshing gear pair of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the cited embodiments are not intended to limit the present invention.

Referring to Figures 1 to 3, an embodiment of the double-arc gap meshing planetary transmission device with small tooth difference of the present invention includes a box body, an eccentric shaft 1 arranged in the box body, and a first eccentric portion 2 of the eccentric shaft Two external gears 4 are respectively provided on the second eccentric part 3 and an internal gear 6 is provided on the inner wall of the box corresponding to the external gear. The internal gear meshes with the external gear, and a plurality of drives are also provided between the two external gears. Pin 7, the two ends of a plurality of driving pins are connected with two end disks 9 to form a planet carrier structure and output power; the end disks are fixed by an oil seal 10 and a bearing 11 to ensure output stability. The matching relationship is shown in Fig. 1.

The number of end discs can be two, which are respectively arranged on both ends of the eccentric shaft in the axial direction to form a bidirectional output effect.

The eccentric shaft drives the outer gear to eccentrically rotate, and the outer gear meshes with the inner gear, and forms the effect of rotating output with less tooth difference. The tooth profile of the internal gear teeth and the tooth profile of the external gear teeth are all circular arcs. The circular arc design is adopted, that is, there is no problem of complex curve modification. The circular arc is easy to prepare, and the preparation accuracy is high. After forming, the arc does not need to be modified by the arc curve, so the preparation difficulty is greatly reduced. As shown in Figures 4 to 6, the initial meshing gap can be generated after the arc structure is assembled, and the gap is stable and controllable; and the double arc design After meshing, the number of meshing teeth can be increased. With reference to the conjugate meshing effect shown in FIG. 7, the meshing range is large, the load-bearing capacity is greatly improved, and the transmission error can be reduced and the transmission accuracy can be improved. In this structural design, the tooth grooves between adjacent gear teeth do not participate in meshing (that is, the tooth grooves between adjacent tooth profiles).

Specifically, the tooth profile of the internal gear mentioned above is obtained by the inner needle 41 arranged on the tooth, and the tooth profile of the external gear is obtained by the outer needle 61 arranged on the tooth. The outer surface of the needle is It is a circular arc structure. Further, a needle roller limit retaining ring 12 is also provided in the box. The needle roller limit retaining ring restricts the matching position of the inner needle and the outer needle to prevent the movement of the needle. When the double needle roller structure is adopted, the needle roller preparation technology is mature and the cost is low; the inner gear and the two outer gears are slotted to accommodate the above inner and outer needles, which is also very convenient, that is, the outer needle Containment grooves are provided on the corresponding teeth and can be formed by conventional processing methods, with high processing accuracy and low difficulty. And in the process of meshing operation, both the inner needle roller and the outer needle roller can perform self-rotating motion. Therefore, while the outer gear drives the outer needle roller to rotate, the outer needle roller can also mesh with the inner needle roller to generate self-rotating motion, thereby reducing the time of meshing rotation. The friction of the teeth reduces the meshing loss and improves the output capacity.

In one embodiment, referring to Figures 8 to 11, both the internal gear and the external gear have teeth with arc-shaped tooth profiles, between the internal gear and its corresponding gear teeth, and between the external gear and its corresponding gear teeth They are all integrally formed structures with stable structure, low preparation cost and low preparation difficulty.

In one embodiment, referring to Figures 12 to 15, the tooth profile of the internal gear is obtained by the inner roller needle arranged on the tooth portion. The outer surface of the needle roller is the arc structure, and the inner roller corresponds to the tooth A containing groove is provided on the part to install and accommodate the inner needle roller. The outer gear has gear teeth with an arc-shaped tooth profile. The outer gear and the gear teeth are integrally formed. The preparation cost is low, the preparation difficulty is small, and the inner needle roller effectively reduces the meshing Rotation loss.

In one embodiment, referring to Figures 16 to 19, the tooth profile of the external gear is obtained by the outer roller needle arranged on the tooth part. The outer surface of the needle roller is the arc structure, and the outer roller corresponds to the tooth A containment groove is provided on the part for mounting and accommodating the outer needle roller. The inner gear has gear teeth with an arc-shaped tooth profile. The inner gear and the gear teeth are integrally formed. The preparation cost is low, the preparation difficulty is small, and the outer needle roller effectively reduces the meshing Rotation loss.

Referring to FIG. 20, the present application also provides a method for forming a double-arc gap meshing gear pair, which includes the following steps:

First determine the arc tooth profile of the external gear, referring to the following equation:

Among them, θ is the arc angle variable;

among them,

Step 3) Calculate the meshing limit function Φ _{t of the} tooth profile of the internal gear and solve the meshing limit value θ _t together with the meshing equation. The equations can be as follows:

The solution is available, the meshing limit value

Step 4) Fit the function in the range of [-θ _t ,θ _t ]

Solve to obtain the single-tooth arc tooth profile radius r _i and the center coordinates (x _c , y _c ) of the internal gear;

Step 5) Calculate the fitting gap

Since the complex curve is the characteristic of multi-tooth meshing with small tooth difference transmission, theoretically all teeth are in contact, half of the gears participate in torque transmission, and the coincidence degree is large, which leads to the need to modify the conjugate tooth profile in the actual application process to prevent The tooth profile interference is caused by machining and assembly errors. The modification provides a meshing gap to form a lubricating oil film and improve the lubrication conditions. After the modification, the number of meshing teeth will be reduced; the arc-shaped internal gear and external gear formed by the above method can Used directly, the gap value can exist, and because it is not a complex curve during processing, the processing accuracy is high, and it can be used directly within the designed gap value without modification. Therefore, the new double needle roller meshing gear with clearance is designed to replace the complex The curved gear pair fundamentally solves the problems of high-precision machining of mixed curves and tooth profile modification. Reduce the manufacturing difficulty and processing cost, and at the same time ensure that in the presence of the meshing gap, the number of meshing teeth is large, the overlap is large, and the high load-bearing capacity is maintained.

The above embodiments are only preferred embodiments for fully explaining the present invention, and the protection scope of the present invention is not limited thereto. The equivalent substitutions or changes made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims

A planetary transmission device with double-arc meshing and small tooth difference, comprising a box body and an eccentric shaft arranged in the box body. The first eccentric part and the second eccentric part of the eccentric shaft are respectively provided with two external gears, An internal gear is provided on the inner wall of the box corresponding to the external gear, and the internal gear meshes with the external gear. The feature is that a plurality of driving pins are also provided between the two external gears, and the two ends of the driving pins are connected with The two end discs are connected and cooperated to form a planet carrier structure and output power. The tooth profile of the internal gear and the external gear are both arcs, and there is an initial meshing gap between the internal gear and the external gear.
The double-arc backlash meshing planetary transmission device with less tooth difference according to claim 1, wherein the internal gear and the external gear both have gear teeth with arc-shaped tooth profiles.
The double-arc backlash meshing planetary transmission device with a small tooth difference according to claim 1, wherein the tooth profile of the internal gear is obtained by an internal roller needle arranged on the tooth portion, and the internal roller is directed against The corresponding tooth part is provided with a containing groove, and the external gear has teeth with a circular arc tooth profile.
The double-arc backlash meshing planetary transmission device with a small tooth difference according to claim 1, wherein the tooth profile of the external gear is obtained by an external needle arranged on the tooth, and the external roller is directed against The corresponding tooth portion is provided with a containing groove, and the internal gear has gear teeth with a circular arc tooth profile.
The double-arc backlash meshing planetary transmission device with a small tooth difference according to claim 1, wherein the tooth profile of the internal gear is obtained by an internal roller needle arranged on the tooth portion, and the internal roller is directed against The corresponding tooth portion is provided with a containing groove, the tooth profile of the external gear is obtained by an outer roller needle provided on the tooth portion, and the corresponding tooth portion is provided with a containing groove.
The double-arc gapped meshing planetary transmission device with a small tooth difference according to any one of claims 3 to 5, wherein a needle roller limit retaining ring is also provided in the box body.
A method for forming a double-arc gap meshing gear pair is characterized in that it comprises the following steps:

Step 1) Determine the number of teeth of the external gear z 1 , the number of teeth of the internal gear z 2 and the arc radius of the external gear tooth profile r o according to the structural size and transmission ratio of the transmission device, and preliminarily determine the eccentricity e and the index circle radius of the external gear R o Range and initial value;

The arc tooth profile equation of the external gear is:

Among them, θ is the arc angle variable;

Step 2) According to the relative motion law of the internal gear and the external gear, use the arc of the external gear tooth profile to envelop the conjugate tooth profile curve of the internal gear to determine the internal gear conjugate tooth profile equation f(x 2 ,y 2 ) And the meshing equation Φ, the conjugate tooth profile equation is obtained as follows:

among them,
They are the rotation angles of internal and external gears, λ = ez 1 /R o ;

Step 3) Calculate the meshing limit function Φ t of the tooth profile of the internal gear and solve the meshing limit value θ t together with the meshing equation. The equations can be as follows:

The solution is available, the meshing limit value

Step 4) Fit the function in the range of [-θ t ,θ t ]
Solve to obtain the single-tooth arc tooth profile radius r i and the center coordinates (x c , y c ) of the internal gear;

Among them, (x 2j ,y 2j ) is the coordinate value of the conjugate tooth profile of the internal gear, and n is the number of data points;

Step 5) Calculate the fitting gap

Step 6) Determine the size of the fitting gap and the initial meshing gap limit value c 0 , such as 0 <c i ≤ c 0 , then the set of design parameters meet the design requirements, determine the design parameters R i and r i , and end the design process, and vice versa , You need to change the optimized parameters eccentricity e, external gear indexing circle radius Ro , and recalculate until the design requirements are met.