阅读说明：本技术 一种大曲率半圆弧状管口加强件滚弯成型模具和成型方法 (Roll bending forming die and method for large-curvature semicircular arc pipe orifice reinforcement ) 是由 白颖 钟李欣 闫宝强 李世峰 黄润卓 范子翠 于 2019-08-02 设计创作，主要内容包括：本申请公开了一种大曲率半圆弧状管口加强件滚弯成型模具和成型方法,成型模具含有成型凸轮、成型凹轮和从动凹轮,成型凸轮、成型凹轮以及从动凹轮分别安装于不对称三轴滚弯机的三个不同的滚轴上。成型时先进行毛坯定位,然后设定成型凸轮、成型凹轮和从动凹轮相对位置关系,其次利用三轴滚弯设备成型,最后管口加强件从三根同步旋转的滚轴间通过,并连续产生轴向和纵向塑性弯曲变形,从而获得所需的截面形状和弧度外形。(The application discloses big camber semicircle arcuation mouth of pipe reinforcement rolls curved forming die and forming method, forming die contain shaping cam, shaping concave wheel and driven concave wheel, and shaping cam, shaping concave wheel and driven concave wheel are installed respectively on the roller bearing of three difference of asymmetric triaxial roll bending machine. During forming, a blank is positioned, relative position relations of a forming cam, a forming concave wheel and a driven concave wheel are set, then three-axis roll bending equipment is used for forming, and finally a pipe orifice reinforcing piece passes through three rollers which rotate synchronously and continuously generates axial and longitudinal plastic bending deformation, so that the required cross section shape and radian appearance are obtained.)

1. The roll bending forming die for the large-curvature semicircular arc pipe orifice reinforcement part is characterized by comprising a forming cam, a forming concave wheel and a driven concave wheel, wherein the forming cam, the forming concave wheel and the driven concave wheel are respectively arranged on three different rolling shafts of an asymmetric triaxial roll bending machine.

2. The roll bending forming die for the large-curvature semi-circular arc-shaped pipe orifice reinforcement piece according to claim 1, wherein the longitudinal outer profile section of the forming cam is matched with the inner shape of the section of the pipe orifice reinforcement piece, the longitudinal outer profile section of the forming concave wheel is matched with the outer shape of the section of the pipe orifice reinforcement piece, the outer shape profile of the driven concave wheel is consistent with that of the forming concave wheel, and the forming cam and the forming concave wheel are guided and positioned through the outer clamping groove.

3. The roll bending die for the large-curvature semi-circular arc-shaped pipe orifice reinforcing member as claimed in claim 2, wherein the distance between the clamping grooves is matched with the size of the cross-section development blank of the pipe orifice reinforcing member.

4. The roll bending mold for the large-curvature semi-circular pipe orifice reinforcement as claimed in claim 1, wherein the asymmetric three-axis roll bending machine comprises an upper roller, a lower roller and a side roller, the upper roller and the lower roller are in a same vertical plane, the side roller is located at a same side of the upper roller and the lower roller, the forming cam is mounted on the upper roller, the forming concave wheel is mounted on the lower roller, and the driven concave wheel is mounted on the side roller.

5. A roll bending forming method for a large-curvature semicircular arc pipe orifice reinforcement is characterized by comprising the following steps:

5-1, positioning the blank;

5-2, setting the relative position relation of the forming cam, the forming concave wheel and the driven concave wheel;

5-3, forming by using a three-axis roll bending device;

5-4 the orifice reinforcement passes between three rollers rotating synchronously and continuously produces axial and longitudinal plastic bending deformation, thus obtaining the required section shape and radian profile.

6. The roll bending forming method for the large-curvature semi-arc pipe orifice reinforcement piece according to claim 5, wherein the specific process of the step 5-1 is as follows:

and placing the unfolded blank of the pipe orifice reinforcement between clamping grooves of the forming concave wheel, and adjusting the distance between the upper rolling shaft and the lower rolling shaft by using a machine tool rotating shaft to ensure that the gap between the forming cam and the forming concave wheel is equal to the material thickness of the pipe orifice reinforcement.

7. The roll bending method for forming a large-curvature semi-circular arc pipe orifice reinforcing member according to claim 5, wherein the step 5-2 comprises the steps of:

7-1, determining the position of the arc center O of the pipe orifice reinforcement;

7-2, determining the longitudinal displacement of the side roller;

7-3 adjusting the relative positions of the forming cam, the forming concave wheel and the driven concave wheel.

8. The roll bending forming method for the large-curvature semi-arc pipe orifice reinforcement piece according to claim 7, wherein the specific process of the step 7-1 is as follows:

and preliminarily determining the position of the arc center O of the pipe orifice reinforcement according to the connecting line of the molding cam and the axis of the molding concave wheel and the integral arc radius R1 of the pipe orifice reinforcement.

9. The roll bending forming method for the large-curvature semi-arc pipe orifice reinforcement piece according to claim 7, wherein the specific process of the step 7-2 is as follows:

the shape of the section of the driven concave wheel notch is matched with the longitudinal projection of the forming cam and the forming concave wheel, and the lateral adjusting handle is used for adjusting the longitudinal displacement of the side roller. The height of the side roller is determined according to the integral arc radius R1 of the pipe orifice reinforcement, the radius of the clamping groove in the driven concave wheel is R2, and the displacement of the driven concave wheel is adjusted to ensure that the distance d from the axis to the circle center O is less than R1+ R2.

10. The roll bending forming method for the large-curvature semi-arc pipe orifice reinforcement piece according to claim 7, wherein the specific processes of the step 7-3 are as follows:

and (3) preliminarily adjusting the distance between the rollers, rolling for a section, measuring by using a sample plate, and further adjusting the distance between the rollers according to the measurement result, wherein the distance d from the axle center of the driven concave wheel to the center O of the pipe orifice reinforcement is R1+ R2-L.

11. The roll bending method for forming a large-curvature semi-circular arc pipe orifice reinforcement member according to claim 10, wherein the size of L is mainly determined by the mechanical properties of the material, i.e. the yield limit and the elastic modulus of the material, and for the a286 alloy material, the value of L is 20-25 mm.

12. The roll bending forming method for the large-curvature semi-arc pipe orifice reinforcement piece according to claim 5, wherein the specific processes of the step 5-3 are as follows:

the unfolded blank enters the clamping groove of the forming concave wheel, is extruded by the forming cam to generate plastic bending deformation along the cross section shape of the roller, and generates friction force between the unfolded blank and the roller under the rotation of the forming concave wheel so as to enable the material to continuously advance, and when the unfolded blank touches the driven concave wheel, lateral pressure is generated so as to enable the pipe orifice reinforcement to be formed.

Technical Field

The invention relates to a sheet metal part forming technology in the field of aircraft manufacturing, in particular to a roll bending forming die and a forming method for a large-curvature semi-arc pipe orifice reinforcing part.

Background

In order to improve the taking-off and landing performance of the turboprop under complex conditions such as high-temperature plateau airports, full-load conditions and the like, a large amount of high-temperature-resistant novel materials and special structures are designed, and particularly in the design of an exhaust pipeline near an engine, an iron-based precipitation-hardening type high-temperature alloy A286 is used for replacing the conventional titanium alloy structural member, so that the high-temperature use environment of not lower than 600-700 ℃ is met.

The pipe orifices of the pipelines such as the exhaust pipe of the turboprop branch aircraft, the silencing cabin and the like are provided with series of semicircular trapezoid-section pipe orifice reinforcements made of high-temperature alloy A286, so that the rigidity and the sealing property of the thin-wall pipe fitting are improved. The A286 alloy has high yield strength, large elastic modulus and high hardening index, so the material has large cold forming resistance, large resilience after forming and difficult finishing.

The curvature of the pipe orifice reinforcing part is large and is in a semi-closed shape, and wrinkles which cannot be eliminated can be generated by traditional punch forming. In aviation enterprises, such as stretch bending forming or numerical control roll bending forming, the method is not suitable for processing the reinforcing rib groove structure sheet metal part with a small section and a diameter of not more than 300 mm. The manually-formed A286 alloy pipe orifice reinforcing piece is high in difficulty and poor in surface quality, a heating correction procedure needs to be arranged in order to ensure the fitting degree of the part and the pipe wall, the manufacturing cost is high, and the production flow is complex. The molding of the semi-circular arc rib groove structural member has the technical constraint brought by the material performance and the process bottleneck brought by the complex structure.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a roll bending method and a forming mold for a nozzle reinforcement having a closed overall shape and a trapezoidal cross section. By utilizing the three-axis roll bending forming principle of a three-roll bending machine, a combined die structure of a pipe orifice reinforcing part and a forming method for mechanically and accurately processing a high-strength alloy closed sheet metal reinforcing part are designed, and efficient forming of parts is realized.

The roll bending forming die comprises a forming cam, a forming concave wheel and a driven concave wheel, wherein the longitudinal outer contour section of the forming cam is matched with the inner shape of the section of the pipe orifice reinforcement, the longitudinal outer contour section of the forming concave wheel is matched with the outer shape of the section of the pipe orifice reinforcement, the outer shape contour of the driven concave wheel is consistent with that of the forming concave wheel, the forming cam and the forming concave wheel are guided and positioned through an outer side clamping groove, and the distance between the clamping grooves is matched with the size of a developed blank of the section of the pipe orifice reinforcement. The asymmetric three-shaft roll bending machine comprises an upper rolling shaft, a lower rolling shaft and side rolling shafts, wherein the upper rolling shaft and the lower rolling shaft are positioned on the same vertical plane, the side rolling shafts are positioned on the same side of the upper rolling shaft and the lower rolling shaft, a forming cam is arranged on the upper rolling shaft, a forming concave wheel is arranged on the lower rolling shaft, and a driven concave wheel is arranged on the side rolling shafts.

A roll bending forming method for a large-curvature semicircular arc pipe orifice reinforcement comprises the following steps:

1, positioning a blank; and placing the unfolded blank of the pipe orifice reinforcement between clamping grooves of the forming concave wheel, and adjusting the distance between the upper rolling shaft and the lower rolling shaft by using a machine tool rotating shaft to ensure that the gap between the forming cam and the forming concave wheel is equal to the material thickness of the pipe orifice reinforcement.

2, setting the relative position relation of the forming cam, the forming concave wheel and the driven concave wheel;

2-1, determining the position of an arc center O of the pipe orifice reinforcement; and preliminarily determining the position of the arc center O of the pipe orifice reinforcement according to the connecting line of the molding cam and the axis of the molding concave wheel and the integral arc radius R1 of the pipe orifice reinforcement.

2-2, determining the longitudinal displacement of the side roller; the shape of the section of the driven concave wheel notch is matched with the longitudinal projection of the forming cam and the forming concave wheel, and the lateral adjusting handle is used for adjusting the longitudinal displacement of the side roller. The height of the side roller is determined according to the integral arc radius R1 of the pipe orifice reinforcement, the radius of the clamping groove in the driven concave wheel is R2, and the displacement of the driven concave wheel is adjusted to ensure that the distance d from the axis to the circle center O is less than R1+ R2.

2-3, adjusting the relative positions of the forming cam, the forming concave wheel and the driven concave wheel. The distance between the rollers is preliminarily adjusted, the rollers are rolled for one section and are measured by a sample plate, then the distance between the rollers is further adjusted according to the measurement result, the distance d from the axle center of the driven concave wheel to the center O of the pipe orifice reinforcing piece is R1+ R2-L, and the value of L is 20-25 mm aiming at the A286 alloy material.

3, forming by using a three-axis roll bending device; the unfolded blank enters the clamping groove of the forming concave wheel, is extruded by the forming cam to generate plastic bending deformation along the cross section shape of the roller, and generates friction force between the unfolded blank and the roller under the rotation of the forming concave wheel so as to enable the material to continuously advance, and when the unfolded blank touches the driven concave wheel, lateral pressure is generated so as to enable the pipe orifice reinforcement to be formed.

The 4-nozzle reinforcement passes through three rollers which rotate synchronously and continuously generates axial and longitudinal plastic bending deformation, thereby obtaining the required section shape and radian profile.

The invention has the beneficial effects that: 1) the forming die adopts a combined forming structure of three sets of rollers, so that the plane shrinkage deformation of a plate is converted into longitudinal extrusion drawing deformation, the deformation mode of the material is changed, a reinforcing rib groove structural member with larger curvature, more closed or even close to a closed round shape can be formed, and the problems that a high-temperature alloy large-curvature revolving body reinforcing member is difficult to form, has large resilience and the like are solved. 2) The installation and operation method of the forming die is simple and convenient, is easy to popularize and realize, and simultaneously adopts the section expansion size for direct forming, thereby reducing the workload of cutting and correcting. 3) The forming method overcomes the defects of high difficulty in manual forming, difficulty in restoring resilience and the like of the traditional punch forming unstable wrinkling, gets rid of dependence on human operating skills, improves the forming accuracy of parts and finally obtains a smooth and streamlined product. 4) The combined die is simple in structure and easy to realize, parts with different curvatures can be formed by using the rollers with a group of section shapes, the number of dies is small, the manufacturing cost is low, and the product quality is stable.

The present application is described in further detail below with reference to the accompanying drawings of embodiments.

Drawings

FIG. 1 is a schematic view of the overall structure and cross-section of a large curvature, trapezoidal notch orifice stiffener

FIG. 2 is a schematic view of the structure of a male mold and a female mold for forming a combined forming mold

FIG. 3 is a schematic view showing the assembling positions of the parts of the combined forming die and the unfolded blank

FIG. 4 is a schematic view showing the position adjustment of the driven concave wheel of the combined forming die

FIG. 5 is a schematic view of the roll-formed nozzle reinforcement

The numbering in the figures illustrates: 1 orifice reinforcement, 2 trapezoidal notches, 3 forming cams, 4 forming concave wheels, 5 driven concave wheels, 6 clamping grooves, 7 unfolded blanks, 8 upper rolling shafts, 9 lower rolling shafts and 10 side rolling shafts

Detailed Description

Referring to the accompanying drawings, an airplane part provided by the embodiment is shown in fig. 1, the part 1 is a large-curvature high-strength alloy sheet metal part, the section of the part is a trapezoid notch 2 and is used for reinforcing the strength and the sealing performance of a pipe fitting, the biggest problem of forming by using the prior art is that the stamping forming is unstable and wrinkles seriously, the manual forming is difficult to yield materials, the dependence on the technical level of workers is large, the surface quality of the part is poor, and the part cannot be formed by aiming at a structure with the integral arc exceeding 1/2 circles.

Forming die that this application provided is shown as drawing 2 fried four minutes in the drawing 3, forming die contains forming cam 3, shaping concave wheel 4 and driven concave wheel 5, 3 vertical outline cross-sections of forming cam and the trapezoidal notch 2 of mouth of pipe reinforcement 1 in the shape phase-match, 4 vertical outline cross-sections of shaping concave wheel and the trapezoidal notch 2 appearance phase-match of mouth of pipe reinforcement 1, 5 appearance profiles of driven concave wheel keep unanimous with shaping concave wheel 4, forming cam 3 and shaping concave wheel 4 carry out guide orientation through outside draw-in groove 6, draw-in groove 6 intervals and the 7 size phase-matches of the cross-section expansion blank of mouth of pipe reinforcement 1.

Before forming, the forming cam 3, the forming concave wheel 4 and the driven concave wheel 5 are respectively arranged on three different rolling shafts of an asymmetric three-shaft bending roll, the asymmetric three-shaft bending roll comprises an upper rolling shaft 8, a lower rolling shaft 9 and side rolling shafts 10, the upper rolling shaft 8 and the lower rolling shaft 9 are positioned on the same vertical plane, the side rolling shafts 10 are positioned on the same side of the upper rolling shaft 8 and the lower rolling shaft 9, the forming cam 3 is arranged on the upper rolling shaft 8, the forming concave wheel 4 is arranged on the lower rolling shaft 9, and the driven concave wheel 5 is arranged on the side rolling shafts 10.

In the application, the position of each part of the forming die is adjusted as shown in figure 4, an expanded blank 7 of a pipe orifice reinforcement member 1 is placed between clamping grooves 6 of a forming concave wheel 4, the distance between an upper rolling shaft 8 and a lower rolling shaft 9 is adjusted by using a machine tool rotating shaft, the gap between a forming cam 3 and the forming concave wheel 4 is equal to the material thickness of the pipe orifice reinforcement member 1, the section of a notch of a driven concave wheel 5 is matched with the longitudinal projection of the forming cam 3 and the forming concave wheel 4, the longitudinal displacement of a side rolling shaft 10 is adjusted by a lateral adjusting handle, the height of the driven concave wheel 5 is determined according to the integral arc radius R1 of the pipe orifice reinforcement member 1, the arc circle center O of the pipe orifice reinforcement member 1 can be preliminarily determined on the connecting line of the axes of the forming cam 3 and the forming concave wheel 4, the radius of the clamping groove in the driven concave wheel 5 is R2, the displacement of the driven concave wheel 5 is adjusted, the distance d from the axes to the circle center, usually, the distance between the rollers is preliminarily adjusted according to the experience, the plates are rolled for a section and measured by a template, then the distance between the rollers is further adjusted according to the measurement result, the readjusted distance mainly depends on the mechanical property of the material, and for the A286 thin-wall large-curvature pipe orifice reinforcing member 1, the distance d from the axle center of the driven concave wheel 5 to the center O of the pipe orifice reinforcing member 1 is R1+ R2- (20-25) mm.

The three-axis roll bending device is used for forming, an unfolded blank 7 enters a clamping groove 6 of a forming concave wheel 4, is extruded by a forming cam 3 to be subjected to plastic bending deformation along the cross section shape of a roller, and under the rotation of the forming concave wheel 4, friction force is generated between the unfolded blank 7 and the roller to enable a material to continuously advance, and when the unfolded blank touches a driven concave wheel 5, lateral pressure is generated to force a pipe orifice reinforcing part 1 to have a certain curvature.

The orifice reinforcement 1 passes between three rollers rotating synchronously and is continuously subjected to axial and longitudinal plastic bending deformation to obtain the desired cross-sectional shape and arc profile.

It should be noted that the integral arc radius of the pipe orifice reinforcement formed by the roll bending forming method is not less than 1.2 times of the working radius of the forming cam; meanwhile, a small section of linear area exists at two ends of the reinforcing piece of the roll-bending forming pipe orifice, and mainly due to the fact that a gap between the forming concave wheel and the driven concave wheel causes the deformed material of the initial section to lack of longitudinal support, process compensation is considered on the length of the unfolded blank in calculation, and the compensation amount of a single-side process is larger than the distance between a lower roller of the forming concave wheel and a side roller of the driven concave wheel after installation and positioning.