Axial closed rolling forming method for barrel part with groove inside

Abstract

The invention provides an axial closed rolling forming method for a barrel part with a groove inside, which comprises the following steps: carrying out special-shaped ring rolling treatment on an upset and punched ring blank with a rectangular cross section to obtain a barrel blank with symmetrical steps at the end parts of the two sides; the cylinder blank is divided into two parts along the central plane of a cylinder shaft, and two same cylinder blanks with L-shaped sections are obtained; one barrel blank is placed in a barrel-shaped lower die of a rolling machine, a conical roller is adopted for rolling the upper end face of the barrel blank downwards, meanwhile, the conical roller rotates around a conical shaft and drives the barrel blank to rotate, and when the conical roller reaches the target downward pressing distance, a barrel part with a groove inside is obtained, and the barrel-shaped lower die is provided with a protrusion corresponding to the groove inside the barrel part; and the outer edge of the demolding plate abuts against the lower end face of the cylinder wall of the cylinder part, the demolding plate is moved upwards, the cylinder part is driven to move upwards, and demolding is completed. The problems that in the prior art, forming defects exist, equipment is limited, materials are wasted, streamlines are damaged, and demolding is difficult are solved.

Description

Technical Field

[0001] The invention relates to the technical field of metal plastic forming, in particular to an axial closed rolling forming method of a cylindrical part with an internal groove. Background Art

[0002] Complex-section cylindrical parts, critical load-bearing components in aerospace equipment, are widely used in the manufacture of rocket fuselages, aircraft fuselages, and space station hulls. A typical example of this type of part is a cylindrical part with internal grooves, characterized by complex cross-sectional profiles and deep walls. Die forging or ring rolling are traditional forming techniques for producing such parts.

[0003] However, the existing technology has the following prominent problems: (1) Forming defects: The traditional ring rolling process uses radial extrusion as the main loading method, which is prone to end face pits and folding defects when forming the groove, and requires complex processes such as riveting and upsetting to control, resulting in a low yield rate; (2) Equipment limitations: The traditional die forging process requires the use of a 10,000-ton press, and the traditional ring rolling process has poor adaptability to special-shaped sections and cannot achieve the overall forming of deep cylinder wall grooves; (3) Material waste and streamline damage: The traditional ring rolling process cannot form parts with irregular grooves in one go, and requires subsequent cutting processes. The cutting process not only reduces material utilization, but also seriously damages the metal streamline; (4) Difficulty in demolding: The internal groove of the formed cylinder part forms a mechanical bite with the mold protrusion, and the geometric locking force needs to be overcome during demolding. The traditional process lacks an effective demolding mechanism, and forced demolding can easily cause deformation of the cylinder part or damage to the mold.

[0004] Therefore, there is an urgent need to develop new processes and equipment suitable for integrally forming the above-mentioned cylindrical parts with internal grooves, so as to make up for the shortcomings of the existing technology. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides an axial closed rolling forming method for a cylindrical member with an internal groove, which solves the problems of forming defects, equipment limitations, material waste, streamline destruction, and demolding difficulties in the prior art.

[0006] According to an embodiment of the present invention, a method for axially closed rolling forming of a cylindrical member with an internal groove comprises the following steps:

[0007] The rectangular cross-section ring blank after upsetting and punching is subjected to special-shaped ring rolling to obtain a tube blank with symmetrical steps on both ends;

[0008] Dividing the cylinder into two along the center plane of the cylinder axis to obtain two cylinders with the same L-shaped cross-section;

[0009] Place one of the tube blanks in the cylindrical lower die of a rolling press, and use a tapered roller to roll down the upper end face of the tube blank. At the same time, the tapered roller rotates around its tapered axis, driving the tube blank to rotate. When the tapered roller reaches the target pressing distance, an inner-grooved cylindrical part is obtained. The cylindrical lower die has a protrusion corresponding to the inner groove of the cylindrical part.

[0010] Let the outer edge of the stripping plate abut against the lower end face of the barrel wall of the cylindrical part, and move the stripping plate upward to drive the cylindrical part upward to complete demolding.

[0011] Preferably, before subjecting the rectangular-section ring blank after upsetting and punching to special-shaped ring rolling to obtain a tube blank with symmetric steps at both ends, the steps of obtaining the rectangular-section ring blank include:

[0012] Blank cutting: Calculate and determine the specifications and weight of the blank according to the geometric shape of the inner-grooved cylindrical part to be formed, and use a sawing machine to cut the blank on a round bar.

[0013] Heating: Heat the blank to the forgeable temperature of the material according to the thermoplastic forming requirements of the blank. After heat preservation, take it out of the furnace for subsequent forging modification.

[0014] Forging modification: Stretch the blank axially, then upset it axially, repeat this process three times of stretching and two times of upsetting, and then stretch it axially and roll and flatten the end face.

[0015] Punching: Heat the blank and upset it axially, then select a punch to punch holes, then roll and trim the blank to eliminate large R corners, and return it to the furnace for heat preservation to obtain a rectangular-section ring blank.

[0016] Preferably, after obtaining two identical L-shaped-section tube blanks, heat treatment is required for the L-shaped-section tube blanks. The heat treatment is to heat the L-shaped-section tube blanks to the forgeable temperature of the material and set the heat preservation time according to the specifications of the L-shaped-section tube blanks.

[0017] Preferably, the step of using a tapered roller to roll down the upper end face of the tube blank, and at the same time, the tapered roller rotates around its tapered axis, driving the tube blank to rotate, and when the tapered roller reaches the target pressing distance, obtaining an inner-grooved cylindrical part includes:

[0018] Arrange the tapered roller on one side of the upper end face of the tube blank, and let the bottom face of the tapered roller roll down the upper end face of the tube blank.

[0019] During the rolling forming process, on the one hand, the tapered roller moves downward, and on the other hand, it rotates around its tapered axis. The frictional force between the tapered roller and the tube blank drives the tube blank to rotate, and the frictional force between the tube blank and the cylindrical lower die drives the cylindrical lower die and the tube blank to rotate synchronously.

[0020] As the cone roller continues to move downward, continuous plastic deformation is generated between the groove tooth forming area of the tube blank and the cone roller and the cylindrical lower die, gradually filling into the groove of the inner groove die. When the cone roller reaches the target downward pressing distance, an inner-grooved cylindrical part is finally obtained.

[0021] Preferably, after arranging the cone roller on one side of the upper end face of the tube blank, a pressure roller is arranged on the other side of the upper end face of the tube blank transversely relative to the cone roller, and the pressure roller presses the upper end face of the tube blank.

[0022] Preferably, when the lower bottom surface of the cone roller rolls over the upper end face of the tube blank, on any contact line between the cone roller and the tube blank, the condition that the cone roller bites into the tube blank must be satisfied, that is:

[0023]

[0024] In the formula, β is the friction angle on the interface, and α is the biting angle.

[0025] The feed distance Δh of the cone roller downward after one rotation of the tube blank must satisfy:

[0026] Δh ≤ 4β 2 S a tanγ

[0027] In the formula, S a represents the distance from the contact line between the cone roller and the upper end face of the tube blank to the vertex O' of the cone roller, and γ is the angle between the cone axis and the horizontal plane.

[0028] The value conditions of the downward pressing speed v of the cone roller and the rotational speed n1 around its cone axis must satisfy:

[0029]

[0030] In the formula, R w is the radius of the middle wall thickness of the upper end face of the tube blank, R a is the meshing line radius of the cone roller at R w , and η is the tangential slip coefficient.

[0031] Preferably, grooves with different axial heights are distributed at the inner port on one side of the inner-grooved cylindrical part.

[0032] Preferably, the L-shaped cross-section tube blank is divided into a groove tooth forming area and a long tube wall. The volume of the groove tooth forming area is equal to the volume of the groove tooth area of the inner-grooved cylindrical part. The arm length and wall thickness of the long tube wall are equal to the arm length and wall thickness of the inner-grooved cylindrical part, and the L-shaped cross-section tube blank has the same weight as the inner-grooved cylindrical part.

[0033] Preferably, the outer edge of the demolding plate abuts against the lower end face of the barrel wall of the barrel member, and the demolding plate is moved upward to drive the barrel member to move upward to complete demolding, including:

[0034] Let the demolding oil cylinder pass through the demolding hole of the wedge-shaped track and abut against the concave portion of the demolding plate, and then let the outer edge of the demolding plate abut against the lower end face of the barrel wall of the barrel member;

[0035] Drive the demolding plate to move upward through the demolding oil cylinder, drive the barrel member to move upward along the movable groove of the demolding plate, gradually separate from the cylindrical lower die, and then take out the barrel member to complete the demolding of the barrel member.

[0036] Preferably, after the demolding of the barrel member is completed, heat treatment needs to be performed on the barrel member, and the heat treatment is adjusted and selected according to the material of the barrel member.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] Compared with the ordinary ring rolling method, axial pressure is the main loading method of the present invention. Through the new technological path of L-shaped barrel blank segmentation and reformation, combined with the synergistic effect of the rotation of the tapered roller and the protrusion of the cylindrical lower die, the integral forming of the barrel member with internal grooves can be achieved at one time. At the same time, through the constraint of the mold groove of the cylindrical lower die, the forming accuracy of the groove tooth area of the barrel blank can be fully guaranteed. Compared with the traditional die forging method, the tapered roller performs "axial" local and progressive rolling on the upper end of the barrel blank, and can achieve forming under a smaller load, with low equipment cost investment. It solves the problems of forming defects, equipment limitations, material waste and streamline damage existing in the prior art, improves the material utilization rate while maintaining the complete metal streamline. In addition, after the rolling forming, the formed barrel member is driven to move upward by the upward movement of the demolding plate, so that the barrel member can be taken out from the cylindrical lower die, realizing the rapid demolding of the barrel member, and solving the problem of difficult demolding existing in the prior art, saving labor and time costs. Description of the Drawings

[0039] Figure 1 It is a process flow diagram of an axial closed-die rolling forming method for a barrel member with internal grooves in Embodiment 1 of the present invention;

[0040] Figure 2 It is a flow step diagram of an axial closed-die rolling forming method for a barrel member with internal grooves in Embodiment 1 of the present invention.

[0041] Figure 3 It is a specific flow chart of the rolling forming of an axial closed-die rolling forming method for a barrel member with internal grooves in Embodiment 1 of the present invention.

[0042] Figure 4Schematic cross-sectional structure diagram of the L-shaped cylinder blank in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0043] Figure 5 Schematic assembly structure diagram during the downward rolling process in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0044] Figure 6 Mathematical model of the conical roller biting into the cylinder blank in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0045] Figure 7 Schematic structure diagram of the inner groove die in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0046] Figure 8 Schematic structure diagram of the outer surrounding cylinder in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0047] Figure 9 Schematic structure diagram of the wedge-shaped track in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0048] Figure 10 Schematic structure diagram of the stripping plate in the axial closed-die rolling forming method of an internally grooved cylinder part according to Embodiment 1 of the present invention;

[0049] Figure 11 Schematic dimension diagram of the target internally grooved cylinder part according to Embodiment 2 of the present invention;

[0050] Figure 12 Schematic cross-sectional structure diagram of the internally grooved cylinder part according to Embodiment 2 of the present invention.

[0051] In the above-mentioned drawings: 1. L-shaped cross-section cylinder blank; 2. Inner groove die; 3. Outer surrounding cylinder; 4. Wedge-shaped track; 5. Stripping plate; 6. Positioning pin; 7. Conical roller; 11. Groove tooth forming area; 12. Long cylinder wall; 21. Stripping plate moving groove; 22. Inner die wedge-shaped groove; 31. Outer die wedge-shaped groove; 41. Demolding hole; 42. Bolt counterbore; 43. Positioning pin hole. Detailed implementation manners

[0052] The technical solutions in the present invention will be further described below with reference to the drawings and embodiments.

[0053] Embodiment 1

[0054] As Figure 1 And Figure 2As shown in the figure, an axial closed die forging forming method for a cylindrical body part with internal grooves according to an embodiment of the present invention includes the following steps:

[0055] S1. Subject the rectangular-section ring blank after upsetting and punching to special-shaped ring rolling to obtain a cylindrical blank with symmetrical steps at both ends;

[0056] Among them, before subjecting the rectangular-section ring blank after upsetting and punching to special-shaped ring rolling to obtain a cylindrical blank with symmetrical steps at both ends, the steps of obtaining the rectangular-section ring blank include:

[0057] Blank cutting: Calculate and determine the specifications and weight of the blank according to the geometric shape of the cylindrical body part with internal grooves to be formed, and use a sawing machine to cut the blank on a round bar;

[0058] Heating: Heat the blank to the forging temperature of the material according to the thermoplastic forming requirements of the blank, keep it warm, and then take it out of the furnace for subsequent forging improvement;

[0059] Forging improvement: Stretch the blank axially, then upset it axially, repeat this three times of stretching and two times of upsetting, and then stretch it axially and roll and flatten the end face;

[0060] Punching: Heat the blank and upset it axially, then select a punch to punch a hole, then roll and trim the blank to eliminate the large R corner, and put it back into the furnace for heat preservation to obtain a rectangular-section ring blank.

[0061] S2. Divide the cylindrical blank into two equal parts along the central plane of the cylinder axis to obtain two identical L-shaped cross-section cylindrical blanks 1;

[0062] Among them, as Figure 4 shown, the L-shaped cross-section cylindrical blank 1 is divided into a groove tooth forming area 11 and a long cylinder wall 12. The volume of the groove tooth forming area 11 is equal to the volume of the groove tooth area of the cylindrical body part with internal grooves, and the arm length and wall thickness of the long cylinder wall 12 are equal to the arm length and wall thickness of the cylindrical body part with internal grooves. The weight of the L-shaped cross-section cylindrical blank 1 is the same as that of the cylindrical body part with internal grooves.

[0063] After obtaining the two identical L-shaped cross-section cylindrical blanks 1, before rolling the obtained L-shaped cross-section cylindrical blanks 1, it is necessary to perform a heat preservation treatment on the L-shaped cross-section cylindrical blanks 1. The heat preservation treatment is: heat the L-shaped cross-section cylindrical blanks 1 to the forging temperature of the material, and then set the conventional heat preservation time according to the specifications of the L-shaped cross-section cylindrical blanks 1.

[0064] S3. Place one of the cylindrical blanks in the cylindrical lower die of the rolling press, and use the tapered roller 7 to roll down the upper end face of the cylindrical blank. At the same time, the tapered roller 7 rotates around the tapered shaft, driving the cylindrical blank to rotate. When the tapered roller 7 reaches the target downward pressing distance, a cylindrical body part with internal grooves is obtained. The cylindrical lower die has a protrusion corresponding to the internal groove of the cylindrical body part;

[0065] Among them, as Figure 3 shown, the upper end face of the cylindrical blank is rolled downward by the tapered roller 7. At the same time, the tapered roller 7 rotates around the tapered axis, driving the cylindrical blank to rotate. When the tapered roller 7 reaches the target downward pressing distance, an inner-grooved cylindrical body part is obtained, including:

[0066] S31. Arrange the tapered roller 7 on one side of the upper end face of the cylindrical blank, and roll the lower bottom surface of the tapered roller 7 on the upper end face of the cylindrical blank;

[0067] Specifically, as Figure 5 shown, the cylindrical lower die is composed of an inner groove die 2, an outer surrounding cylinder 3, a wedge-shaped track 4, a stripping plate 5 and a positioning pin 6. The gap between the inner groove die 2 and the outer surrounding cylinder 3 forms a cylindrical wall cavity. The inner groove die 2 and the outer surrounding cylinder 3 are connected to the working platform of the rolling press through the wedge-shaped track 4. The wedge-shaped track 4 passes through the inner groove die 2, the outer surrounding cylinder 3 and the stripping plate 5 and is connected to the working platform of the rolling press by bolts. The inner groove die 2 and the outer surrounding cylinder 3 determine the central position through the positioning pin 6 on the wedge-shaped track 4.

[0068] Before rolling, embed the long cylindrical wall 12 of the L-shaped cross-section cylindrical blank 1 downward into the cylindrical wall cavity surrounded by the inner groove die 2 and the outer surrounding cylinder 3. Place the inner diameter protruding part of the groove tooth forming area 11 of the L-shaped cross-section cylindrical blank 1 on the upper end face of the groove of the inner groove die 2. Arrange the tapered roller 7 on one side of the upper end face of the L-shaped cross-section cylindrical blank 1. Preferably, a pressure roller can be arranged on the other side of the upper end face of the L-shaped cross-section cylindrical blank 1 transversely relative to the tapered roller 7. The pressure roller presses the upper end face of the L-shaped cross-section cylindrical blank 1 to prevent the L-shaped cross-section cylindrical blank 1 from warping and misaligning under the action of the tapered roller 7.

[0069] S32. During the rolling forming process, on the one hand, the tapered roller 7 moves downward, and on the other hand, it rotates around its tapered axis. The frictional force between the tapered roller 7 and the cylindrical blank drives the cylindrical blank to rotate, and the frictional force between the cylindrical blank and the cylindrical lower die drives the cylindrical lower die and the cylindrical blank to rotate synchronously;

[0070] Specifically, during the rolling process, the lower bottom surface of the tapered roller 7 rolls the upper end surface of the L-shaped cross-section tube blank 1. During the rolling forming process, on the one hand, the tapered roller 7 moves downward at a speed v, and on the other hand, it rotates around its tapered axis at a rotational speed n1. The frictional force between the tapered roller 7 and the L-shaped cross-section tube blank 1 drives the L-shaped cross-section tube blank 1 to rotate at a rotational speed n2, and the frictional force between the L-shaped cross-section tube blank 1 and the cylindrical lower die drives the cylindrical lower die to rotate synchronously with the L-shaped cross-section tube blank 1. As the tapered roller 7 continuously moves downward, the groove tooth forming area 11 of the L-shaped cross-section tube blank 1 undergoes continuous plastic deformation between the tapered roller 7 and the cylindrical lower die, gradually filling into the groove of the inner groove die 2, and finally obtaining a cylindrical part with an internal groove.

[0071] Among them, as Figure 6 shown, when the lower bottom surface of the tapered roller 7 rolls the upper end surface of the tube blank, on any contact line between the tapered roller 7 and the tube blank, the condition that the tapered roller 7 bites into the tube blank must be satisfied, that is, the horizontal friction component in the contact area must exceed the horizontal component of the pressure, that is:

[0072]

[0073] In the formula, β is the friction angle on the interface, and α is the bite-in angle.

[0074] Furthermore, α can be approximately equal to the ratio of the contact arc length l to the equivalent rolling radius R l That is:

[0075]

[0076] In the formula, R l can be calculated according to the geometric relationship as R l = R a / cosγ, R a is the radius of the tapered roller 7 at the contact line, and γ is the angle between the tapered axis and the horizontal.

[0077] The contact arc length l can be expressed as:

[0078]

[0079] In the formula, S a represents the distance from the contact line to the vertex O' of the tapered roller 7, and Δh represents the downward feed distance of the tapered roller 7 after one revolution of the blank.

[0080] From this, it can be obtained that:

[0081] Δh ≤ 4β 2 S a tanγ

[0082] In the formula, this formula represents the condition of the downward feeding distance at the contact line where the tapered roller 7 bites into the tube blank.

[0083] The downward feeding distance Δh of the tapered roller 7 after one revolution of the tube blank must satisfy:

[0084] Furthermore, the ratio of the downward speed v of the tapered roller 7 to the rotational speed n2 of the tube blank is expressed as the downward feeding distance Δh of the tapered roller 7 after one revolution of the blank, that is:

[0085]

[0086] The relationship between the active rotational speed n1 of the tapered roller 7 and the passive rotational speed n2 of the tube blank is:

[0087]

[0088] In the formula, R w is the radius of the middle wall thickness of the upper end face of the tube blank, and R a is the meshing line radius of the tapered roller 7 at R w , and η is the slip coefficient in the tangential direction, and its value range is between 0.5 and 1.3.

[0089] From this, it can be obtained that:

[0090]

[0091] Furthermore, it can be obtained that:

[0092]

[0093] In the formula, this formula represents the value conditions of v and n1 when the tapered roller 7 bites into the tube blank at the contact line.

[0094] Preferably, the taper of the tapered roller 7 is 60°.

[0095] Preferably, the rotational speed of the tapered roller 7 is 35 r / min, and the downward pressing speed of the tapered roller 7 is 2 mm / s.

[0096] S33. As the tapered roller 7 continues to move downward, the groove tooth forming area 11 of the tube blank undergoes continuous plastic deformation between the tapered roller 7 and the cylindrical lower die, and gradually fills into the groove of the inner groove die 2. When the tapered roller 7 reaches the target downward pressing distance, an inner-grooved cylindrical part is finally obtained.

[0097] Specifically, the target downward pressing distance S is equal to the height h1 of the blank forming area minus the distance h2 from the upper end face of the die groove area to the upper end face of the die (or the height h2 of the blank immersed in the die before processing in the blank forming area), and grooves with different axial heights are distributed at the inner port on one side of the obtained inner-grooved cylindrical part.

[0098] S4. Make the outer edge of the demolding template 5 abut against the lower end face of the barrel wall of the barrel member, move the demolding template 5 upward to drive the barrel member to move upward and complete demolding.

[0099] Among them, the step of making the outer edge of the demolding template 5 abut against the lower end face of the barrel wall of the barrel member, moving the demolding template 5 upward to drive the barrel member to move upward and complete demolding includes:

[0100] Make the demolding oil cylinder pass through the demolding hole 41 of the wedge-shaped track 4 and abut against the recess of the demolding template 5, and then make the outer edge of the demolding template 5 abut against the lower end face of the barrel wall of the barrel member;

[0101] Drive the demolding template 5 to move upward through the demolding oil cylinder, drive the barrel member to move upward along the demolding template movable groove 21, gradually separate from the cylindrical lower mold, and then take out the barrel member to complete the demolding of the barrel member.

[0102] Specifically, as Figure 7 shown, the maximum outer diameter of the inner groove mold 2 is equal to the inner diameter of the hot size of the long barrel wall 12 of the barrel blank; the groove geometry of the inner groove mold 2 matches the geometry of the inner groove of the cylindrical part. The mold wall of the inner groove mold 2 is symmetrically provided with a demolding template movable groove 21, and the demolding template movable groove 21 is used to ensure the up-and-down free movement of the demolding template 5. After the mold wall of the inner groove mold 2 rotates 90° relative to the demolding template movable groove 21, an inner mold wedge-shaped groove 22 is symmetrically opened, and the inner mold wedge-shaped groove 22 is used to ensure the passing of the wedge-shaped track 4.

[0103] As Figure 8 shown, the inner diameter of the outer surrounding cylinder 3 is equal to the outer diameter of the hot size of the long barrel wall 12 of the barrel blank. The mold wall of the outer surrounding cylinder 3 is symmetrically provided with an outer mold wedge-shaped groove 31, and the wedge-shaped groove is used to ensure the passing of the wedge-shaped track 4.

[0104] As Figure 9 shown, the wedge-shaped track 4 is used to limit the up-and-down movement of the inner groove mold 2 and the outer surrounding cylinder 3. The cross-sectional geometry and size of the wedge-shaped track 4 match the geometry and size of the inner mold wedge-shaped groove 22 of the inner groove mold 2 and the outer mold wedge-shaped groove 31 of the outer surrounding cylinder 3. A demolding hole 41 is opened at the center of the wedge-shaped track 4, and the demolding hole 41 is used to ensure the free expansion and contraction of the jacking oil cylinder on the rolling press workbench. Six bolt counterbore holes 42 are symmetrically drilled along the length direction of the wedge-shaped track 4, and the bolt counterbore holes 42 are used to ensure that bolts fix the wedge-shaped track 4 on the rolling press workbench. Eight positioning pin holes 43 are drilled along the length and width symmetry directions of the wedge-shaped track 4, and the positioning pin holes 43 are used to fix the positioning pin 6, and the positioning pin 6 is used to position the center position of the cylindrical lower mold on the rolling press workbench.

[0105] As shown Figure 10 in the figure, the center of the demolding plate 5 is a concave structure, and the concave structure is placed above the demolding hole 41 of the wedge-shaped track 4. The outer edge radius of the demolding plate 5 is the same as the inner diameter of the outer cylinder, and the width of the demolding plate 5 is the same as the groove width of the demolding plate moving groove 21.

[0106] During the demolding process, the demolding oil cylinder passes through the demolding hole 41 of the wedge-shaped track 4 and presses against the concave part of the demolding plate 5. The outer edge of the demolding plate 5 presses against the lower end face of the barrel wall of the inner grooved barrel part forging. The inner grooved barrel part forging and the demolding plate 5 move upward along the demolding plate moving groove 21 to complete demolding.

[0107] After the barrel part is demolded, heat treatment needs to be carried out on the barrel part, and the heat treatment is adjusted and selected according to the material of the barrel part.

[0108] Specifically, when the barrel part is made of 7050 aluminum alloy (the material of the barrel part includes but is not limited to 7050 aluminum alloy), the heat treatment includes quenching and artificial aging treatment. Among them, quenching includes: heat preservation treatment at 477±5°C for 6h, and then water cooling; artificial aging treatment includes: heat preservation treatment at 120±5°C for 6h, and then heat preservation treatment at 175±5°C for 6h, and then air cooling.

[0109] The detailed working process of this embodiment is as follows:

[0110] First, blanking, according to the geometric shape of the inner grooved barrel part to be formed, calculate and determine the specifications and weights of the blanks, and use a sawing machine to cut the blanks on the round bar; then heating, heat the blanks to the forging temperature of the material according to the thermoplastic forming requirements of the blank materials, and after heat preservation, take them out of the furnace for subsequent forging; then forging, elongate the blank axially, then upset it axially, repeat three elongations and two upsets in this way, and then elongate it axially and roll it to a flat end face; then punching, heat the blank and upset it axially, then select a punch to punch holes, then roll and trim the blank and eliminate the large R corner, and return to the furnace for heat preservation; then ring rolling, perform special-shaped cross-section ring rolling treatment on the rectangular cross-section ring blank after upsetting and punching to obtain a barrel blank with symmetric steps at both ends; finally cutting, cut the barrel blank with symmetric steps at both ends in half along the barrel axis center plane to obtain two identical L-shaped cross-section barrel blanks 1, and return to the furnace for heat preservation.

[0111] After the holding time is reached, the inner groove mold 2 and the outer cylinder 3 are first placed on the rolling machine workbench, and then the wedge-shaped track 4 is passed through the inner groove mold 2 and the outer cylinder 3, and the positioning pins 6 are fixed in the positioning pin holes 43 of the wedge-shaped track 4, so that the inner groove mold 2 and the outer cylinder 3 are in the space surrounded by multiple positioning pins 6 to position the cylindrical lower mold on the rolling machine workbench. After adjusting the positions together (the inner groove mold 2 and the outer cylinder 3 are concentric, and the fixing holes of the wedge-shaped track 4 should be aligned with the screw holes of the rolling machine workbench), the wedge-shaped track 4 is fixed to the rolling machine workbench by bolts. After all the molds are fixed, the long cylinder wall 12 of the obtained L-shaped cross-section cylinder blank 1 is embedded downward in the cylinder wall cavity surrounded by the inner groove mold 2 and the outer cylinder 3, and the inner diameter of the groove tooth forming area 11 of the cylinder blank is protruded. The outgoing part is placed on the upper end face of the groove of the inner groove die 2, and the tapered roller 7 is arranged on one side of the upper end face of the L-shaped cross-section tube blank 1, so that the lower bottom face of the tapered roller 7 rolls the upper end face of the L-shaped cross-section tube blank 1. During the rolling forming process, the tapered roller 7 moves downward at a speed v on the one hand, and rotates around its tapered axis at a speed n1 on the other hand. The friction between the tapered roller 7 and the L-shaped cross-section tube blank 1 drives the L-shaped cross-section tube blank 1 to rotate, and the friction between the L-shaped cross-section tube blank 1 and the cylindrical lower die drives the cylindrical lower die and the L-shaped cross-section tube blank 1 to rotate synchronously. As the tapered roller 7 continues to move downward, the groove tooth forming area 11 of the L-shaped cross-section tube blank 1 produces continuous plastic deformation between the tapered roller 7 and the cylindrical lower die, and gradually fills into the groove of the inner groove die 2. When the tapered roller 7 reaches the target downward pressing distance, a cylindrical part with an internal groove can be obtained.

[0112] After obtaining the cylindrical part with an internal groove, the demoulding oil cylinder is allowed to pass through the demoulding hole 41 of the wedge-shaped track 4 to press against the recessed part of the demoulding plate 5, and then the outer edge of the demoulding plate 5 is allowed to press against the lower end surface of the cylinder wall of the cylindrical part. The demoulding oil cylinder drives the demoulding plate 5 to move upward, and drives the cylindrical part to move upward along the movable groove 21 of the demoulding plate, so that the cylindrical part can be separated from the cylinder wall cavity surrounded by the inner groove mold 2 and the outer surrounding cylinder 3, and then the cylindrical part is taken out, thereby completing the demoulding of the cylindrical part.

[0113] Compared with the ordinary ring rolling method, the axial pressure is the main loading method of the present invention. Through the new process path of splitting and reforming the L-shaped tube blank, combined with the synergistic effect of the rotation of the conical roller 7 and the protrusion of the cylindrical lower die, the integral forming of the cylindrical body part with internal grooves can be achieved at one time. At the same time, through the constraint of the mold groove of the cylindrical lower die, the forming accuracy of the groove tooth area of the tube blank can be fully guaranteed. Compared with the traditional die forging method, the conical roller 7 performs "axial" local and progressive rolling on the upper end of the tube blank, which can achieve forming under a smaller load, with low equipment cost investment, solving the problems of forming defects, equipment limitations, material waste and streamline damage existing in the prior art, improving the material utilization rate while maintaining the complete metal streamline. In addition, after the rolling forming, the formed cylindrical body part is driven to move upward by the upward movement of the demoulding plate 5, so that the cylindrical body part can be taken out from the cylindrical lower die, realizing the rapid demoulding of the cylindrical body part and solving the problem of difficult demoulding existing in the prior art, saving labor and time costs.

[0114] Embodiment 2

[0115] As Figure 11 and Figure 12 shown, this embodiment provides a cylindrical body part with internal grooves. The maximum outer diameter of the cylindrical body part is 600 mm, the inner diameter of the groove end is 490 mm, the inner diameter of the long barrel wall 12 is 530 mm, the barrel height is 223 mm, the highest point of the groove step is 40 mm, and the lowest point of the groove step is 35 mm. The material of the cylindrical body part with internal grooves is 7050 aluminum alloy, the density is 2.82 g / cm3, the Poisson's ratio v is 0.32 - 0.36, the Young's modulus E is 70000 MPa, the yield strength σ s is 455 MPa, and the tensile strength σ p is 524 MPa.

[0116] The axial closed-die rolling forming method of the cylindrical body part with internal grooves in this embodiment includes the following steps:

[0117] (1) Blank making:

[0118] According to Figure 11 the geometric dimensions shown, determine the blank with a specification of Φ350×259 mm and a weight of 73.7 kg cut from a circular bar stock, and heat the blank to 420 ± 10 °C for heat preservation treatment for 180 min.

[0119] Then draw the blank axially to L = (300 ± 10) mm, and then upset it axially to H = (250 ± 10) mm. Repeat this process of three draws and two upsets, and finally draw and round the blank axially to H = (300 ± 5) mm, and then roll and flatten the end face.

[0120] The blank is then heated to 420±10°C and kept warm for 120 minutes, then axially upset to H=(150±5)mm, and then punched with a Φ95mm-Φ125mm punch, with a punch core thickness of ≤75mm; the blank is rounded to trim the bulge and eliminate the large R angle.

[0121] The blank is then heated to 420±10° C. and kept warm for 100 minutes, and then rolled on a ring rolling mill into a tube blank with symmetrical steps on both ends.

[0122] The tube blank with symmetrical steps on both ends is divided into two along the center plane of the tube axis to obtain two identical L-shaped cross-section tube blanks 1, which are returned to the furnace and kept warm for 90 minutes.

[0123] (2) Axial closed rolling forming:

[0124] Setting rolling parameters: according to the hot forging requirements of 7050 aluminum alloy, the rotation speed of the tapered roller 7 is set to 35r / min, the pressing speed is 2mm / s, and the pressing displacement of the tapered roller 7 is set to 27mm according to the height of the groove tooth forming area 11 of the L-shaped cross-section tube blank 1 above the mold part.

[0125] The tube blank obtained in step (1) is returned to the furnace while hot and kept warm for 90 minutes before being taken out. The long tube wall 12 of the tube blank is embedded downward in the tube wall cavity surrounded by the inner groove mold 2 and the outer surrounding cylinder 3. The inner diameter protruding part of the groove tooth forming area 11 of the tube blank is placed on the upper end face of the groove of the inner groove mold 2, and the tapered roller 7 is arranged on one side of the upper end face of the tube blank.

[0126] At the start of rolling, the lower surface of the tapered roller 7 rolls the upper end surface of the tube blank. During the rolling process, the tapered roller 7 moves downward at a speed of 2 mm / s and rotates around its tapered axis at a speed of 35 r / min. The friction between the tapered roller 7 and the tube blank drives the tube blank to rotate, while the friction between the tube blank and the cylindrical lower die drives the cylindrical lower die and the tube blank to rotate synchronously. As the tapered roller 7 continues to move downward, the groove-toothed forming area 11 of the tube blank undergoes continuous plastic deformation between the tapered roller 7 and the cylindrical lower die, gradually filling the groove of the inner groove die 2.

[0127] When the tapered roller 77 reaches the target downward pressing distance, the tapered roller 7 moves upward to leave the inner grooved cylindrical part, the demoulding cylinder passes through the demoulding hole 41 of the wedge-shaped track 4 and presses against the recessed part of the demoulding plate 5, the outer edge of the demoulding plate 5 presses against the lower end face of the cylinder wall of the inner grooved cylindrical part, the inner grooved cylindrical part and the demoulding plate 5 move upward along the movable groove 21 of the demoulding plate, the inner grooved cylindrical part is taken out, and the demoulding of the inner grooved cylindrical part is completed.

[0128] (3) Heat treatment:

[0129] The grooved cylindrical body part obtained in step (2) is subjected to quenching heat treatment, with the heating temperature being 477 ± 5 °C, holding for 6 h and then water cooling;

[0130] Then, the grooved cylindrical body part is subjected to artificial aging treatment, with the heating temperature being 120 ± 5 °C, holding for 6 h, then the heating temperature being 175 ± 5 °C, holding for 6 h and then air cooling.

[0131] The embodiment of the present invention can integrally form a grooved cylindrical body part under a relatively small load, with high material utilization rate and forming quality, and easy demolding.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. An axial closed-die rolling forming method for a cylindrical body part with internal grooves, characterized in that: It includes the following steps: Perform special-shaped ring rolling on the upset-forged and punched rectangular-section ring blank to obtain a cylindrical blank with symmetrical steps at both ends; Cut the cylindrical blank in half along the central plane of the cylinder axis to obtain two identical L-shaped-section cylindrical blanks; Place one of the cylindrical blanks in the cylindrical lower die of a rolling press, and use a tapered roller to roll down the upper end face of the cylindrical blank. At the same time, the tapered roller rotates around the taper axis, driving the cylindrical blank to rotate. When the tapered roller reaches the target downward pressing distance, an inner-grooved cylindrical part is obtained. The cylindrical lower die has a protrusion corresponding to the inner groove of the cylindrical part; Let the outer edge of the stripping plate abut against the lower end face of the barrel wall of the cylindrical part, and move the stripping plate upward to drive the cylindrical part upward to complete demoulding.

2. The axial closed-die rolling forming method for a cylindrical body part with internal grooves as claimed in claim 1, wherein: Before performing special-shaped ring rolling on the upset-forged and punched rectangular-section ring blank to obtain a cylindrical blank with symmetrical steps at both ends, the steps of obtaining the rectangular-section ring blank include: Blank cutting: According to the geometric shape of the inner-grooved cylindrical part to be formed, calculate and determine the specifications and weight of the blank, and use a sawing machine to cut the blank on a round bar; Heating: Heat the blank to the forgeable temperature of the material according to the thermoplastic forming requirements of the blank. After heat preservation, take it out of the furnace for subsequent forging; Forging modification: Stretch the blank axially, then upset it axially, repeat three stretches and two upsets in this way, and then stretch axially and roll and flatten the end face; Punching: Heat the blank and upset it axially, then select a punch to punch holes, then roll and trim the blank to eliminate large R corners, and return it to the furnace for heat preservation to obtain a rectangular-section ring blank.

3. The axial closed-die rolling forming method of a cylindrical body part with internal grooves as claimed in claim 1, wherein: After obtaining the two identical L-shaped-section cylindrical blanks, heat preservation treatment needs to be performed on the L-shaped-section cylindrical blanks. The heat preservation treatment is to heat the L-shaped-section cylindrical blanks to the forgeable temperature of the material and set the heat preservation time according to the specifications of the L-shaped-section cylindrical blanks.

4. A method for axial closed-die rolling forming of a cylindrical body part with internal grooves as claimed in claim 1, characterized in that: The step of using a tapered roller to roll down the upper end face of the cylindrical blank, and at the same time, the tapered roller rotates around the taper axis, driving the cylindrical blank to rotate. When the tapered roller reaches the target downward pressing distance, an inner-grooved cylindrical part is obtained, including: Arrange the tapered roller on one side of the upper end face of the cylindrical blank, and let the bottom surface of the tapered roller roll down the upper end face of the cylindrical blank; During the rolling forming process, the tapered roller moves downward on the one hand and rotates around its taper axis on the other hand. The frictional force between the tapered roller and the cylindrical blank drives the cylindrical blank to rotate, and the frictional force between the cylindrical blank and the cylindrical lower die drives the cylindrical lower die to rotate synchronously with the cylindrical blank; As the tapered roller continues to move downward, continuous plastic deformation occurs in the groove tooth forming area of the cylindrical blank between the tapered roller and the cylindrical lower die, and gradually fills into the groove of the inner groove die. When the tapered roller reaches the target downward pressing distance, an inner-grooved cylindrical part is finally obtained.

5. A method for axial closed-die rolling forming of a cylindrical body part with internal grooves as claimed in claim 4, characterized in that: After arranging the tapered roller on one side of the upper end face of the cylindrical blank, arrange a pressure roller on the other side of the upper end face of the cylindrical blank transversely relative to the tapered roller, and the pressure roller presses the upper end face of the cylindrical blank.

6. The axial closed-die rolling forming method of an inner-grooved cylindrical body part as claimed in claim 4, wherein: When the bottom surface of the tapered roller rolls down the upper end face of the cylindrical blank, on any contact line between the tapered roller and the cylindrical blank, the condition that the tapered roller bites into the cylindrical blank must be satisfied, that is: In the formula, β is the friction angle at the interface, and α is the bite-in angle. The feeding distance Δh downward of the conical roller after the cylindrical blank rotates one circle must satisfy: Δh ≤ 4β 2 S a tanγ Wherein, S a represents the distance from the contact line between the conical roller and the upper end face of the cylindrical blank to the vertex O' of the conical roller, and γ is the angle between the conical axis and the horizontal plane. The value conditions of the downward pressing speed v of the conical roller and the rotational speed n1 around its conical axis must satisfy: Wherein, R w is the radius of the middle wall thickness of the upper end face of the cylinder blank, and R a is the meshing line radius of the tapered roller at R w , and η is the slip coefficient in the tangential direction.

7. The axial closed die rolling forming method for a cylindrical body part with internal grooves as claimed in claim 1, characterized in that: Axially different-height grooves are distributed at the inner port on one side of the inner grooved cylindrical body part.

8. The axial closed-die rolling forming method of a cylindrical body part with internal grooves as claimed in claim 1, wherein: The L-shaped cross-section cylindrical blank is divided into a groove tooth forming area and a long cylindrical wall. The volume of the groove tooth forming area is equal to the volume of the groove tooth area of the inner grooved cylindrical body part. The arm length and wall thickness of the long cylindrical wall are equal to the arm length and wall thickness of the inner grooved cylindrical body part, and the L-shaped cross-section cylindrical blank has the same weight as the inner grooved cylindrical body part.

9. A method for axial closed-die rolling forming of a cylindrical body part with internal grooves as claimed in claim 1, characterized in that: Let the outer edge of the stripping template abut against the lower end face of the cylindrical wall of the cylindrical body part, and move the stripping template upward to drive the cylindrical body part to move upward to complete stripping, including: Let the stripping oil cylinder pass through the stripping hole of the wedge-shaped track and abut against the concave part of the stripping template, and then let the outer edge of the stripping template abut against the lower end face of the cylindrical wall of the cylindrical body part; Drive the stripping template to move upward through the stripping oil cylinder, drive the cylindrical body part to move upward along the movable groove of the stripping template, gradually separate from the cylindrical lower die, and then take out the cylindrical body part to complete the stripping of the cylindrical body part.

10. A method for axial closed-die rolling forming of a cylindrical body part with internal grooves as claimed in claim 1, characterized in that: After the cylindrical body part is stripped, heat treatment needs to be carried out on the cylindrical body part, and the heat treatment is adjusted and selected according to the material of the cylindrical body part.

Images