CN114769454A

CN114769454A - Flexible gear and strengthening and toughening cold machining method thereof

Info

Publication number: CN114769454A
Application number: CN202210416628.4A
Authority: CN
Inventors: 夏琴香; 程秀全; 肖刚锋; 郭明天
Original assignee: Guangzhou Guanglei Electromechanical Equipment Technology Co ltd; South China University of Technology SCUT
Current assignee: Guangzhou Guanglei Electromechanical Equipment Technology Co ltd; South China University of Technology SCUT
Priority date: 2022-04-20
Filing date: 2022-04-20
Publication date: 2022-07-22
Anticipated expiration: 2042-04-20
Also published as: CN114769454B

Abstract

The invention discloses a flexible gear and a strengthening and toughening cold processing method thereof; the method comprises the steps of spinning a steel plate blank by a three-spinning wheel single-pass staggered spinning blank consisting of a double-faced spinning wheel and two conical-faced spinning wheels, spinning the tooth form of a part by a toothed spinning wheel, and finally cutting a small amount of redundant materials at the mouth and the bottom and drilling the bottom to finish the efficient strengthening and toughening cold processing preparation of the flexible wheel part. The method completely reserves the internal fiber tissue of the material of the flexible working part of the part, and is favorable for improving the product quality and prolonging the service life of the part. And the production process is simplified, the processing flow is obviously shortened, and the production efficiency is effectively improved. Meanwhile, the equipment is simple, and the manufacturing cost of parts is reduced.

Description

Flexible gear and strengthening and toughening cold machining method thereof

Technical Field

The invention relates to the field of special processing of mechanical engineering, in particular to a flexible gear (cup-shaped harmonic flexible gear) and a strengthening and toughening cold processing method thereof.

Background

The harmonic gear reducer is widely applied to the fields of aviation, aerospace, robots and the like, wherein a cup-shaped flexible gear part needs to keep excellent flexibility in the working process, the wall thickness of a non-tooth part is only 0.4mm, the thickness of a tooth part is usually only 0.7mm, the processing is difficult, and the following processing methods are mainly adopted at present;

firstly, a bar stock is directly cut to obtain a blank, and then gear cutting is carried out. But not only the material waste is serious, but also the fibers in the material are cut off, thereby reducing the strength and the fatigue life of the workpiece;

secondly, a forging method is adopted to roughly manufacture a shallow and thick cup-shaped blank, then a blank for cutting machining is manufactured through flow spinning, and finally teeth are manufactured through cutting, so that the thickness of the part meets the design requirement, the utilization rate of the material is improved to a certain extent, and the integrity of the fiber tissue in the material is still damaged;

thirdly, spin forming is performed using a slab, but in order to improve the spinnability of the material, various methods of heating or applying a pulse current to assist spin forming are used, which leads to the defects of complicated processing apparatus, complicated processing process, and the like, and finally leads to the increase of the processing cost and rejection rate of parts.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the prior art and provide a flexible gear and a strengthening and cold-processing method thereof.

The invention is realized by the following technical scheme:

a method for strengthening and toughening cold working of a flexible gear comprises the following steps:

step one, calculating the thickness of a tooth part blank:

firstly, calculating the material area of the cross section of the tooth part 13 of the flexible gear;

under the condition of keeping the cross section area and the inner diameter of the tooth part 13 unchanged, calculating the thickness of the blank required by the tooth part 13;

step two, blanking of the plate blank:

selecting steel plates with the same thickness according to the thickness of the bottom 11 of the flexible gear, increasing the length of the flexible gear by 5-10 mm, filling the structure of the bottom 11 to calculate the volume of a blank, calculating the diameter of a circular plate blank according to the volume, and finally punching and blanking;

step three, spinning and blank making:

positioning the circular slab on a core mold 5 and clamping the slab by a tail jacking block 3; uniformly distributing a double-faced spinning wheel 6 and two conical spinning wheels 7 around the circumference of the core mold 5, wherein the two conical spinning wheels 7 keep equidistant positions in the axial direction and the radial direction, and the double-faced spinning wheel 6 and the conical spinning wheels 7 are arranged at equal intervals in the axial direction and the radial direction;

then, the clearance between the core mould and the double-surface spinning wheel 6 and the conical surface spinning wheel 7 is finely adjusted, which specifically comprises the following steps:

the clearance between the double-faced spinning roller 6 and the core mold 5 is adjusted to be the thickness of the bottom 11 of the flexible gear; then the clearance between the two conical spinning wheels 7 and the core mould 5 is adjusted to the thickness required by the wall part 12 of the flexible wheel until the spinning of the wall part 12 is finished; after the spinning of the wall part 12 is finished, the gaps between the two conical spinning wheels 7 and the core die 5 are adjusted to the thickness required by the tooth part 13 of the flexible wheel (controlled by a numerical control program carried by the equipment) until the spinning of the tooth part 13 is finished; finally, the thickness required by the tooth parts 13 and the wall parts 12 is obtained;

step four, rotating the teeth: the core mold 5 is fed in the radial direction by a toothed rotary wheel 8 to perform rotary machining on the tooth portion 13 of the flexible wheel.

In the second step, in the punching and blanking process, a central hole is punched according to the position of the axis of the bottom 11 of the flexible gear, and a side hole with the diameter smaller than that of the central hole is punched at one side of the central hole, so that the blank is positioned and prevented from rotating during spinning operation.

After the tooth rotating operation is completed, a finishing process is also performed: and cutting off redundant materials at the mouth part 14 and the bottom part 11 of the flexible gear part, and finishing the processing of the circular hole at the bottom part of the flexible gear part.

When the step three is arranged in a staggered manner, the position sequence is as follows: the double-face spinning wheel 6 is axially arranged in the front radial direction and the conical-face spinning wheel 7 is axially arranged in the rear radial direction.

And step four, when the rotary teeth are formed, a rotary wheel 8 with teeth is adopted for feeding along the radial direction.

Step four, when the rotary teeth are formed, two symmetrically arranged toothed rotary wheels 8 can be adopted for feeding along the radial direction; the two rotary wheels with teeth 8 have the same shape, and the tooth shapes are aligned and kept to rotate synchronously during installation.

The flexible gear obtained by the processing method can be applied to the fields of aviation, aerospace, robots and the like.

Compared with the prior art, the invention has the following advantages and effects:

the flexible gear is prepared by adopting a steel plate blank, spinning the steel plate blank by a three-spinning wheel single-pass staggered spinning blank consisting of a double-faced spinning wheel and two conical spinning wheels, spinning the tooth shape of a part by a toothed spinning wheel, and finally cutting and drilling the bottom of the part by a small amount of redundant materials at the mouth and the bottom of the part to finish the efficient strengthening and toughening cold processing preparation of the flexible gear part. The method completely reserves the fiber tissue in the material of the flexible working part of the part, and is beneficial to improving the product quality and prolonging the service life of the part. And the production process is simplified, the processing flow is obviously shortened, and the production efficiency is effectively improved. Meanwhile, the equipment is simple, and the manufacturing cost of parts is reduced.

Drawings

FIG. 1 is a schematic view of a compliant gear to be produced by the present invention;

FIG. 2 is a schematic diagram of the present invention for calculating the volume of material required for a compliant gear;

FIG. 3 is a schematic of the original blanking profile of the inventive gear;

FIG. 4 is a schematic view of the spinning wheel arrangement and spinning trajectory of the present invention;

FIG. 5 is a schematic drawing of the spinning of the present invention using a single toothed spinning wheel to form teeth.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Examples

FIG. 1 shows a structure diagram of a flexible gear part, and the material is 40 CrNiMoA. The cold working preparation method comprises the following steps:

(1) tooth blank thickness calculation: in the tooth-shaped part of the part, the cross-sectional area of the material can be calculated to be 109mm²The thickness of the tooth blank can be calculated to be 0.7mm, as shown in fig. 2, while keeping the inner diameter constant and the cross-sectional area constant. That is, in the case of spinning the blank, the thickness of the wall portion was 0.45mm, and the thickness of the tooth portion was 0.7mm, which was different by 0.25 mm.

(2) Blanking of a plate blank: lengthening the mouth part of the blank calculated in the previous step by 8mm to reach a total length of 38mm, and filling the bottom of the blank with a thickness of 2.5mm, as shown in FIG. 2, wherein the total material volume required by calculation is 8100mm³. By referring to the thickness of the bottom of the part of 2.5mm, a 2.5mm thick 40CrNiMoA steel plate was selected, and the diameter of the round billet was calculated to be 64.5 mm. A central hole phi 14 at the bottom of the reference part punches a hole phi 12 at the center of the blank, and then a bolt hole phi 6.3 is selected optionally, and a hole phi 6 is punched at the original position, as shown in figure 3.

(3) Spinning and blank making: as shown in fig. 4, the round slab 4 is pressed against the core mold 5 by the positioning pins 1, the rotation preventing pins 2 and the tail knock block 3. A complex surface spinning wheel 6 and two conical surface spinning wheels 7 are uniformly wound around the core mould 5 at an interval of 120 degrees (only one conical surface spinning wheel is schematically shown in fig. 4), the two conical surface spinning wheels 7 are positioned at equidistant positions in the axial direction and the radial direction, and the axial offset behind the motion direction of the complex surface spinning wheel 6 is 8mm.

The next step is to adjust the clearance between the spinning roller and the core mold: the clearance between the double-surface spinning wheel and the core mold is adjusted to be 2.5mm, and the clearances between the two conical surface spinning wheels and the core mold are both adjusted to be 0.45 mm. During spinning, as shown in fig. 4, the conical surface spinning roller moves according to the track B, the axial offset between the spinning rollers is kept, the feeding track of the double-surface spinning roller can be synchronous with the conical surface spinning roller or can move according to the track A, and the spinning of the blank is completed through single-pass spinning, so that the blank shown in fig. 2 is obtained.

(4) Rotating the teeth: as shown in fig. 5, the blank is subjected to a rotary-toothed machining by feeding a toothed rotary wheel 8 in a trajectory C.

Preferably, two identical toothed rotary wheels can be symmetrically arranged on two sides of the core mold, and the blank is synchronously subjected to rotary tooth forming, so that the shape deviation caused by eccentric load can be overcome. The two toothed rotating wheels are required to ensure that the tooth profiles are aligned and can rotate synchronously during installation.

(5) Trimming: and (5) cutting off a small amount of redundant materials at the mouth and the bottom of the semi-finished product after the teeth are rotated according to the size requirement, and finishing the processing of the circular hole at the bottom of the part.

As described above, the present invention can be preferably implemented.

The present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents and fall within the scope of the present invention.

Claims

1. A flexible gear strengthening and toughening cold working method is characterized by comprising the following steps:

step one, calculating the thickness of a tooth part blank:

firstly, calculating the material area of the cross section of a tooth part (13) of the flexible gear;

under the condition of keeping the cross section area and the inner diameter of the tooth part (13) unchanged, calculating the thickness of the blank required by the tooth part (13);

step two, blanking of the plate blank:

selecting steel plates with the same thickness according to the thickness of the bottom (11) of the flexible gear, increasing the length of the flexible gear by 5-10 mm, filling the structure of the bottom (11) to calculate the volume of a blank, calculating the diameter of a circular plate blank according to the volume, and finally punching and blanking;

step three, spinning and blank making:

positioning a circular slab (4) on a core mold (5) and clamping the slab by using a tail jacking block (3); uniformly distributing a double-surface spinning wheel (6) and two conical surface spinning wheels (7) around the circumference of a core mold (5), wherein the two conical surface spinning wheels (7) keep equidistant positions in the axial direction and the radial direction, and the double-surface spinning wheel (6) and the conical surface spinning wheels (7) are arranged at equal intervals in the axial direction and the radial direction;

then, the clearance between the core mould and the compound surface spinning wheel (6) and the conical surface spinning wheel (7) is finely adjusted, specifically:

adjusting the gap between the complex surface spinning wheel (6) and the core mould (5) to the thickness of the bottom (11) of the flexible wheel; then the gaps between the two conical spinning wheels (7) and the core die (5) are adjusted to the thickness required by the wall part (12) of the flexible wheel until the spinning of the wall part (12) is finished; after the spinning of the wall part (12) is finished, the gaps between the two conical spinning wheels (7) and the core die (5) are adjusted to be the thickness required by the tooth part (13) of the flexible wheel until the spinning of the tooth part (13) is finished; finally, the thickness required by the tooth part (13) and the wall part (12) is obtained;

step four, rotating the teeth: the core mold (5) is fed in the radial direction by a rotary wheel (8) with teeth, and the teeth (13) of the flexible wheel are processed by rotary teeth.

2. The flexible gear strengthening and toughening cold working method according to claim 1, wherein in the second step, a central hole is punched according to the position of the axis of the flexible gear bottom (11) in the punching and blanking process, and a side hole with a diameter smaller than that of the central hole is punched at one side of the central hole for positioning and preventing the blank from rotating in the spinning process.

3. The flexspline strengthening and cold working method of claim 2 wherein, in step four, after the rotation of the spline, there is a trimming process: and cutting off redundant materials at the mouth (14) and the bottom (11) of the flexible gear part, and finishing the processing of the circular holes at the bottom of the flexible gear part.

4. The flexspline strengthening and cold working method according to claim 3, wherein the three steps are staggered and arranged in the following position sequence: the double-surface rotating wheel (6) is axially arranged in the front radial direction and is arranged outside, and the conical surface rotating wheel (7) is axially arranged in the rear radial direction.

5. The flexspline toughening cold working process of claim 4, wherein in step four, the helical teeth are formed by feeding a single toothed wheel (8) radially.

6. The flexspline toughening cold working method according to claim 4, wherein in step four, when forming the helical teeth, two symmetrically arranged toothed rotating wheels (8) are used for feeding in the radial direction.

7. The flexspline toughening cold working process according to claim 6, wherein the two toothed rotors (8) are identical in shape and mounted to ensure tooth alignment and maintain synchronous rotation.

8. A flexible wheel for use in aeronautics, astronautics or robotics applications obtainable by a process according to any one of claims 1 to 7.