CN114769454B - A flexspline and its strengthening and toughening cold working method - Google Patents

Abstract

The invention discloses a flexible gear and a strengthening and toughening cold processing method thereof; the method comprises the steps of adopting a steel plate blank, spinning and forming a blank through a three-spinning roller formed by a compound-surface spinning roller and two conical-surface spinning rollers in a single-pass staggered way, spinning and forming the tooth shape of a part through a toothed spinning roller, and finally cutting and forming a small amount of redundant materials at the mouth and the bottom and forming holes at the bottom to finish the high-efficiency toughening cold-working 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.

Description

A flexspline and its strengthening and toughening cold working method

technical field

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

Background technique

Harmonic gear reducers have been widely used in aviation, aerospace, robotics and other fields. The cup-shaped flexspline parts must maintain excellent flexibility during work. The wall thickness of the toothless part is only 0.4mm, and the toothed part The thickness is often only 0.7mm, and the processing is more difficult. At present, there are mainly the following processing methods;

One is that the blank is obtained by direct cutting of the bar stock, and then the gear cutting process is performed. But this not only wastes material seriously, but also cuts off the internal fibers of the material, thereby reducing the strength and fatigue life of the workpiece;

The second is to use the forging method to roughly produce shallow and thick cup-shaped blanks, and then flow-spin the blanks for cutting processing, and finally cut the teeth to make the thickness of the parts meet the design requirements, which improves the material to a certain extent. The utilization rate of the material, but still destroys the integrity of the fiber structure inside the material;

The third is that the slab is used for spinning forming processing, but in order to improve the spinability of the material, various heating or pulse current loading methods are used to assist spinning forming, which leads to defects such as complicated processing devices and cumbersome processing processes. , resulting in higher parts processing costs and scrap rates.

Contents of the invention

The object of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art, and provide a flexspline and its strengthening and toughening cold working method.

The present invention realizes through following technical scheme:

A method for strengthening and toughening cold working of flexwheels, comprising the steps of:

Step 1, the calculation of the thickness of the tooth blank:

First calculate the material area of the tooth portion 13 cross-section of the flexspline;

In the case of keeping the cross-sectional area of the tooth portion 13 constant and the internal diameter constant, calculate the blank thickness required for the tooth portion 13;

Step 2, slab blanking:

Select steel plates of the same thickness according to the thickness of the bottom 11 of the flexspline, increase the length of the flexspline by 5-10 mm, fill up the structure of the bottom 11 to calculate the volume of the blank, and then use this volume to calculate the diameter of the circular slab, and finally punch down material;

Step 3, spin blank:

Position the circular slab on the mandrel 5, and clamp it with the tail top block 3; distribute a complex surface roller 6 and two conical rollers 7 evenly around the core mold 5, and the two conical rollers 7 maintain equidistant positions in both the axial and radial directions, while the multi-faced roller 6 and the conical roller 7 are arranged at a staggered distance in the axial and radial directions;

Next, fine-tune the gap between the multi-surface rotary wheel 6 and the conical surface rotary wheel 7 and the mandrel, specifically:

Adjust the gap between the double-faced roller 6 and the mandrel 5 to the thickness of the bottom 11 of the flexspline; then adjust the gap between the two conical rollers 7 and the core mold 5 to the required thickness of the wall 12 of the flexspline until The spinning of the wall part 12 is completed; after the spinning of the wall part 12 is completed, (controlled by the numerical control program that comes with the equipment) the gap between the two conical surface spinning wheels 7 and the mandrel 5 is adjusted to be set by the tooth part 13 of the flexspline. Thickness is required until the spinning of the tooth part 13 is completed; finally, the required thickness of the tooth part 13 and the wall part 12 is obtained;

Step 4, tooth rotation: use the toothed wheel 8 to feed radially along the mandrel 5, and perform tooth rotation processing on the tooth part 13 of the flexspline.

In the above step 2, during the stamping and blanking process, a center hole is punched out according to the position of the axis of the flexspline bottom 11, and then a side hole with a diameter smaller than the center hole is punched out on one side of the center hole for use in Positioning and preventing blank rotation during spinning.

In the above step 4, after the gear rotation operation is completed, there is another trimming process: cutting off the excess material at the mouth 14 and bottom 11 of the flexspline part, and completing the processing of the round hole at the bottom of the flexspline part.

When the above step 3 is arranged in a staggered distance, the position sequence is as follows: the axial direction of the complex surface roller 6 is in the front radial direction, and the axial direction of the conical surface roller 7 is in the rear radial direction.

In the above step 4, when the spiral tooth is formed, a toothed spiral wheel 8 is used to feed in the radial direction.

In the above step 4, when the spiral tooth is formed, preferably, two symmetrically arranged toothed spiral wheels 8 can be used to feed in the radial direction; the two toothed spiral wheels 8 have the same shape, and the teeth are aligned and synchronized during installation. turn.

The flexible spline obtained by the processing method of the present invention can be applied in the fields of aviation, spaceflight, robot and the like.

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

The flexible spline of the present invention is prepared by using a steel plate blank, spinning the billet through a three-roller single-pass staggered pitch consisting of a double-faced roller and two conical rollers, and then spinning the tooth shape of the part through a toothed roller, and finally Then, a small amount of excess material at the mouth and bottom is cut and holes are made at the bottom to complete the high-efficiency strengthening and toughening cold processing of flexspline parts. This method completely preserves the internal fiber structure of the material in the flexible working part of the part, which is beneficial to improving product quality and service life of the part. Moreover, the production process is simplified, the processing flow is significantly shortened, and the production efficiency is effectively improved. Simultaneously, the equipment is simple and the manufacturing cost of parts is reduced.

Description of drawings

Fig. 1 is the flexible gear schematic diagram to be prepared by the present invention;

Fig. 2 is the schematic diagram of the principle of calculating the material volume required by the flexible gear in the present invention;

Fig. 3 is a schematic diagram of the original blanking shape of the gear of the present invention;

Fig. 4 is a schematic diagram of the wheel layout and the spinning track of the present invention;

Fig. 5 is a schematic diagram of the spinning of the present invention using a single toothed wheel.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments.

Example

Figure 1 shows the structural diagram of the flexspline parts, the material is 40CrNiMoA. The cold working preparation method steps are as follows:

(1) Calculation of the thickness of the tooth blank: In the tooth shape part of the part, the cross-sectional area of the material can be calculated as 109mm ² , and the thickness of the tooth blank can be calculated while keeping the inner diameter and cross-sectional area constant. is 0.7mm, as shown in Figure 2. That is, when spinning the blank, the thickness of the wall is 0.45mm, the thickness of the teeth is 0.7mm, and the difference between the two is 0.25mm.

(2) Slab blanking: lengthen the length of the billet mouth calculated in the previous step by 8mm, so that the total length reaches 38mm, and then fill up all parts of the bottom with a thickness of 2.5mm, as shown in Figure 2, calculate the total material required The volume is 8100mm ³ . Referring to the thickness of the bottom part of 2.5mm, select 40CrNiMoA steel plate with a thickness of 2.5mm, so the diameter of the round billet can be calculated as 64.5mm. Referring to the center hole φ14 at the bottom of the part, punch a φ12 hole in the center of the blank, and then choose a bolt hole φ6.3, and punch a φ6 hole at the original position, as shown in Figure 3.

(3) Spinning blank: as shown in Figure 4, the round slab 4 is pressed against the mandrel 5 with the positioning pin 1, the anti-rotation pin 2 and the tail top block 3. A complex surface roller 6 and two conical surface rollers 7 are spaced at 120° evenly around the mandrel 5 (only one conical surface roller is schematically shown in Fig. 4 ), and the two conical surface rollers 7 are located on the shaft The equidistant position in the direction and radial direction, the axial offset behind the moving direction of the complex surface roller 6 is 8mm.

The next step is to adjust the gap between the rotary wheel and the core mold: adjust the gap between the compound surface rotary wheel and the core mold to 2.5mm, and adjust the gap between the two conical surface rotary wheels and the core mold to 0.45mm. During spinning, as shown in Figure 4, the conical rollers move according to track B, and the axial offset between the rollers is maintained, while the feed track of the compound rollers can be synchronized with the conical rollers , can also move according to track A, complete the spinning of the blank through single-pass spinning, and obtain the blank shown in Figure 2.

(4) Tooth rotation: As shown in Figure 5, a toothed wheel 8 is used to feed the blank according to the track C to process the tooth rotation.

Preferably, two completely identical toothed wheels can be symmetrically arranged on both sides of the mandrel to synchronously form the blank, which can overcome the shape deviation caused by the eccentric load. At this time, the two toothed wheels are required to ensure that the teeth are aligned and can rotate synchronously during installation.

(5) Trimming: According to the size requirements, a small amount of excess material at the mouth and bottom of the semi-finished product after the tooth rotation is cut off, and the processing of the round hole at the bottom of the part is completed.

As described above, the present invention can be preferably carried out.

The implementation of the present invention is not limited by the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods, and are all included in within the protection scope of the present invention.

Claims (8)

1. a flexwheel strengthening and toughening cold working method is characterized in that comprising the steps: Step 1, the calculation of the thickness of the tooth blank: First calculate the material area of the tooth portion (13) cross-section of the flexspline; In the case of keeping the cross-sectional area of the tooth portion (13) constant and the internal diameter constant, calculate the blank thickness required by the tooth portion (13); Step 2, slab blanking: Select a steel plate of the same thickness according to the thickness of the bottom (11) of the flexspline, increase the length of the flexspline by 5 to 10 mm, fill up the structure of the bottom (11) to calculate the volume of the blank, and then use this volume to calculate the diameter of the circular slab , and finally stamping and blanking; Step 3, spin blank: Position the circular slab (4) on the mandrel (5), and clamp it with the end top block (3); place a double-faced roller (6) and two conical rollers (7) around the mandrel ( 5) Evenly distributed in the circumferential direction, the two conical surface rollers (7) maintain equidistant positions in the axial and radial directions, and the complex surface roller (6) and the conical surface roller (7) are axially and radially Even staggered layout; Next, fine-tune the gap between the complex surface wheel (6) and the tapered surface wheel (7) and the mandrel, specifically: Adjust the gap between the compound roller (6) and the mandrel (5) to the thickness of the bottom (11) of the flexible wheel; then adjust the gaps between the two conical rollers (7) and the mandrel (5) to The required thickness of the wall part (12) of the wheel, until the spinning of the wall part (12) is completed; All are adjusted to the required thickness of the tooth portion (13) of the flexspline until the spinning of the tooth portion (13) is completed; finally the required thickness of the tooth portion (13) and the wall portion (12) is obtained; Step 4, tooth rotation: use the toothed wheel (8) to feed radially along the mandrel (5), and process the tooth part (13) of the flexspline. 2. according to claim 1 described flexspline strengthening and toughening cold working method, it is characterized in that, in step 2, in stamping and blanking process, punch out a center hole according to the axis position of flexspline bottom (11), and then On one side of the center hole, a side hole with a diameter smaller than the center hole is punched out, which is used for positioning and preventing the blank from rotating during the spinning operation. 3. The flexspline strengthening and toughening cold working method according to claim 2 is characterized in that, in step 4, after the gear rotation operation is completed, there is also a finishing process: the mouth (14) and bottom (11) of the flexspline part Excess material is cut off and the round hole at the bottom of the flexible spline part is finished. 4. According to claim 3, the flexwheel strengthening and toughening cold working method is characterized in that, when step 3 is arranged at a staggered distance, the position sequence is: the compound surface roller (6) is axially in front and radially outward, and the conical surface roller (7) The axial direction is in the rear radial direction. 5. The flexwheel strengthening and toughening cold working method according to claim 4, characterized in that, in step 4, when the spiral teeth are formed, a single toothed spiral wheel (8) is used to feed in the radial direction. 6. The flexwheel strengthening and toughening cold working method according to claim 4, characterized in that, in step 4, when the spiral teeth are formed, two symmetrically arranged toothed spiral wheels (8) are used to feed in the radial direction. 7. The cold working method for strengthening and toughening flexwheels according to claim 6, characterized in that the two toothed wheels (8) have the same shape, and the alignment of the tooth shapes is ensured and the synchronous rotation is maintained during installation. 8. The processing method according to any one of claims 1-7, the obtained flexible spline is applied in the field of aviation, spaceflight or robot.

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