CN217809559U - Extrusion device - Google Patents

Abstract

The utility model belongs to the technical field of the equipment is reinforceed in the cold extrusion in hole, a extrusion device is disclosed. The extrusion device comprises a core rod and a support rod, wherein one end of the core rod is a working end, a mounting hole is formed in the center of the axial direction of the working end, a plurality of working rings with the diameters larger than the diameters of workpiece assembling holes are convexly arranged on the periphery of the free end of the working end at intervals, an extrusion seam is formed in the hole wall of the mounting hole along the axial direction of the core rod, so that the diameters of the working rings can be reduced, and the working end can be sleeved with a workpiece. The support rod is inserted into the mounting hole before the mandrel is drawn out of the workpiece assembly hole to support the side wall of the mounting hole, and the assembly hole is subjected to multiple extrusion strengthening by the working ring in the process of drawing the mandrel out of the workpiece assembly hole so that the assembly hole wall forms a uniform residual stress field, thereby prolonging the service life of the workpiece. Meanwhile, the diameter of the working ring can not change and ensure the good extrusion effect of the assembly hole, and the working ring can not generate plastic deformation at the same time, so that the service life of the extrusion device is ensured.

Description

Extrusion device

Technical Field

The utility model relates to a hole cold extrusion reinforces equipment technical field, especially relates to an extrusion device.

Background

The assembly holes are formed in most of parts on the aircraft, and the parts are connected and assembled through the fasteners installed in the assembly holes, so that stress concentration is easily formed on the hole edges of the assembly holes, cracks are easily generated, the fatigue performance of the parts is reduced, and the service life of the parts is shortened.

In order to solve the problems, the cold extrusion strengthening of the perforated structural part by adopting the slotted bush and the solid extrusion device in the prior art is an advanced hole cold extrusion strengthening technology in the current aircraft manufacturing industry, and can delay the generation of cracks around the assembly hole, increase the fatigue performance of the assembly hole workpiece and prolong the service life of the assembly hole workpiece. However, the slotted bush is adopted, so that the slotted bush is in indirect contact with the hole wall of the assembly hole, one part of the extrusion amount acts on the hole wall, and the other part of the extrusion amount can cause plastic deformation of the slotted bush, the service life of the slotted bush is shortened, the slotted bush cannot be subjected to multiple times of extrusion strengthening, and the cost of the hole extrusion strengthening process is increased. However, the solid core extrusion device is adopted, the extrusion device is in direct contact with the hole wall, and the diameter of the solid core extrusion device is invariable, so that the method cannot perform extrusion strengthening with large extrusion amount, and the extrusion strengthening effect of the assembly hole is not obvious.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a can carry out many times extrusion and reinforce, the assembly hole extrusion reinforces effectual and longe-lived extrusion device.

To achieve the purpose, the utility model adopts the following technical proposal:

an extrusion apparatus comprising:

one end of the mandrel is a working end, a mounting hole is formed in the axial center of the working end, a plurality of working rings are arranged on the free end of the working end in a protruding mode at intervals in the circumferential direction, the diameter of each working ring is larger than the diameter of an assembling hole of a workpiece, an extrusion seam is formed in the hole wall of each mounting hole in the axial direction of the mandrel, so that the diameter of each working ring can be reduced, and the workpiece can be sleeved on the working end;

and the support rod is inserted into the mounting hole so as to limit the diameter of the working ring.

Preferably, the working end comprises:

the working part is provided with a working ring in the circumferential direction;

the workpiece passes through the working part and is sleeved on the placing part; and

the diameter of the working part is larger than that of the placing part, and the transition part is located between the working part and the placing part and is uniformly transited from the working part to the placing part.

Preferably, the free end of the working portion is tapered in diameter to provide a mounting guide for the workpiece.

Preferably, a transition fillet is arranged between the working ring and the working part.

Preferably, the distance between two adjacent working rings is smaller than the thickness of the workpiece.

Preferably, the end point of the extrusion seam is provided with a stop-grain hole.

Preferably, the ratio between the length of the squeeze gap and the diameter of the mounting hole is less than 7.

Preferably, one end of the support rod is gradually reduced in diameter.

Preferably, the length of the support rod is longer than the depth of the mounting hole.

Preferably, the pressing device further comprises:

two auxiliary plates are arranged on two of the workpieces, and a through hole with the same diameter as the diameter of the workpiece assembling hole is formed in the center of each auxiliary plate.

Has the advantages that: the utility model discloses an extrusion device has seted up the mounting hole through the work end at the plug, and the extrusion seam has been seted up along the axial of plug to the pore wall of mounting hole for the diameter that sets up in the diameter of work end periphery is greater than the working ring of work piece pilot hole can reduce, thereby makes the work piece can locate on the plug through the pilot hole cover. The plurality of working rings are arranged at the working end of the mandrel in a protruding mode at intervals, the supporting rods are inserted into the mounting holes before the workpiece assembling holes are drawn out of the mandrel, so that the side walls of the mounting holes are supported, and in the process that the workpiece assembling holes are drawn out of the mandrel, the assembling holes are subjected to multiple times of extrusion strengthening of the working rings, so that the assembling hole walls form uniform residual stress fields, and the service life of the workpiece can be prolonged. Meanwhile, the diameter of the working ring can not change and ensure the good extrusion effect of the assembly hole, and the working ring can not generate plastic deformation while the support rod ensures the service life of the extrusion device.

Drawings

Fig. 1 is a first schematic structural diagram of an extrusion apparatus provided in an embodiment of the present invention;

fig. 2 is a schematic structural diagram ii of an extrusion apparatus according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a mandrel provided by an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a support rod provided by the embodiment of the present invention;

fig. 5 is a schematic structural diagram of a workpiece according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an auxiliary board provided in an embodiment of the present invention;

fig. 7 is a graph showing the distance between the hole wall penetration layer of the assembly hole and the hole wall and the residual stress;

fig. 8 is a graph showing the distance between the middle layer of the hole wall of the assembly hole and the hole wall and the residual stress;

fig. 9 is a graph showing the distance between the hole wall extrusion layer of the assembly hole and the hole wall and the change of the residual stress;

fig. 10 is a graph showing the distance between the hole wall penetration layer and the hole wall and the residual stress of the assembly hole in three cases according to the embodiment of the present invention;

fig. 11 is a graph showing the distance between the middle layer of the hole wall of the assembly hole and the hole wall and the change of the residual stress in three cases;

fig. 12 is a graph showing the distance between the hole wall extrusion layer of the assembly hole and the hole wall and the change of the residual stress in three cases.

In the figure:

100. a core rod; 110. a working end; 111. a working part; 1111. a working ring; 1112. transition fillets; 112. a placement section; 113. a transition portion; 114. extruding the seam; 1141. a pattern-stop hole; 115. mounting holes; 120. an installation end;

200. a support rod;

300. a workpiece; 310. an assembly hole;

400. an auxiliary plate; 410. and (6) a via hole.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature "on," "above" and "over" the second feature may include the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is at a higher level than the second feature. "beneath," "under" and "beneath" a first feature includes the first feature being directly beneath and obliquely beneath the second feature, or simply indicating that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

The embodiment provides an extrusion device, which can extrude assembly holes on parts assembled into an aircraft, so that the assembly holes form a uniform residual stress field, and the service life of the parts is prolonged.

In the prior art, a slotted bushing and a solid extrusion device are often adopted to carry out cold extrusion strengthening on a structural part with holes. However, the use of the split bush causes plastic deformation of the split bush, reduces the service life of the split bush, prevents the split bush from being subjected to multiple extrusion strengthening, and increases the cost of the hole extrusion strengthening process. However, the solid extrusion device is adopted, and the diameter of the solid extrusion device is invariable, so that the method cannot perform extrusion strengthening with large extrusion amount, and the extrusion strengthening effect of the assembly hole is not obvious.

In order to solve the above problem, as shown in fig. 1-2, the extrusion apparatus of the present embodiment includes a mandrel 100 and a support rod 200, wherein one end of the mandrel 100 is a working end 110, a mounting hole 115 is formed in an axial center of the working end 110, a plurality of working rings 1111 having a diameter larger than that of the assembly holes 310 of the workpiece 300 are protruded on an outer periphery of a free end of the working end 110 at intervals, and an extrusion slit 114 is formed on a hole wall of the mounting hole 115 along the axial direction of the mandrel 100, so that the diameter of the working rings 1111 can be reduced, and the workpiece 300 can be sleeved on the working end 110. The support rods 200 are inserted into the mounting holes 115 before the mandrel 100 is drawn out of the assembly holes 310 to provide support for the sidewalls of the mounting holes 115, and the assembly holes 310 are subjected to multiple compression strengthening by the working rings 1111 during the process of drawing the mandrel 100 out of the assembly holes 310, so that the hole walls of the assembly holes 310 form a uniform residual stress field, thereby prolonging the service life of the workpiece 300. Meanwhile, the support rod 200 can ensure that the diameter of the working ring 1111 is not changed to ensure good extrusion effect of the assembly hole 310, and the working ring 1111 is not subjected to plastic deformation, thereby ensuring the service life of the extrusion device.

Turning now to the mandrel 100 in detail, as shown in fig. 3, one end of the mandrel 100 is a working end 110, and the other end is a mounting end 120, wherein the mounting end 120 is mounted on a drawing device, and the drawing device can provide a drawing force to the mandrel 100, so that the working end 110 of the mandrel 100 can be drawn out of the assembly hole 310 of the workpiece 300. Alternatively, the drawing device may be a telescopic motor, the mounting end 120 is provided with a thread, and the mounting end 120 may be screwed to an output end of the telescopic motor. Of course, the drawing device may have another structure as long as it can drive the mandrel 100 to perform a drawing motion, and this embodiment is not limited in particular. The working end 110 includes a working portion 111, a placing portion 112 and a transition portion 113, wherein the working ring 1111 is disposed on the circumferential direction of the working portion 111, the workpiece 300 is sleeved on the placing portion 112 through the working portion 111, the diameter of the working portion 111 is larger than that of the placing portion 112, and the transition portion 113 is located between the working portion 111 and the placing portion 112 and is uniformly transited from the working portion 111 to the placing portion 112. The working portion 111 can prevent the stress concentration from occurring at the joint between the working ring 1111 and the mandrel 100 due to a severe transition between the working ring 1111 and the mandrel 100, thereby reducing the life of the mandrel 100. The transition portion 113 enables the mandrel 100 to be gradually and uniformly stressed on the assembly hole 310 when the mandrel is drawn out of the assembly hole 310, avoids transition difficulty of the assembly hole 310 during severe transition between the placing portion 112 and the working portion 111 when the placing portion 112 reaches the working portion 111, and avoids damage caused by large stress on a joint of the placing portion 112 and the working portion 111.

Further, a transition fillet 1112 is arranged between the working ring 1111 and the working portion 111, so that stress concentration of the workpiece 300 on the working portion 111 when the workpiece passes through the working ring 1111 can be prevented, the hole wall of the assembling hole 310 can be prevented from being damaged, and fatigue cracks can be effectively prevented from being initiated.

Further, the distance between two adjacent working rings 1111 is smaller than the thickness of the workpiece 300, so that the hole wall of the assembly hole 310 of the workpiece 300 can continuously and uninterruptedly receive the action of the working rings 1111 when passing through the working rings 1111, and finally obtain a good mechanical effect, and the problem of rebound caused by too far distance between two adjacent working rings 1111 is avoided.

In the present embodiment, the thickness of the workpiece 300 is 3mm, so the distance between two adjacent working rings 1111 of the present embodiment is less than 3mm, and of course, in other embodiments, the distance between two adjacent working rings 1111 is determined according to the thickness of the workpiece 300 of the corresponding embodiment.

Alternatively, as shown in fig. 3, the free end of the working portion 111 is tapered toward the free end to provide a guide for the workpiece 300 to facilitate nesting of the workpiece 300 on the placing portion 112 through the free end.

As shown in fig. 3, the end point of the pressing slit 114 is located at the placing portion 112, and a thread-stop hole 1141 is opened at the important point of the pressing slit 114. The anti-crack hole 1141 can prevent cracks from occurring due to the existence of the slit, and ensure the service life of the mandrel 100.

Further, the ratio of the length of the extrusion slit 114 to the diameter of the mounting hole 115 is less than 7, thereby ensuring the rigidity of the mandrel 100.

Further, the plurality of extrusion slits 114 are symmetrically formed in the hole wall of the mounting hole 115, so that the extrusion force of the working ring 1111 against the hole wall of the mounting hole 310 is uniform when the mandrel 100 is drawn out of the mounting hole 310, thereby ensuring a good machining effect of the workpiece 300.

As will be described in detail below, as shown in fig. 1 to 2 and 4, the diameter of the end of the support rod 200 inserted into the mounting hole 115 is gradually reduced to form a guide for facilitating the insertion of the support rod 200.

Further, the length of the support rod 200 is longer than the depth of the installation hole 115, thereby giving sufficient support force to the mandrel 100 so that the mandrel 100 has sufficient rigidity when being withdrawn out of the fitting hole 310 so that the hole wall of the fitting hole 310 is sufficiently processed.

Alternatively, as shown in fig. 1, 2 and 6, the pressing device further includes two auxiliary plates 400, one auxiliary plate 400 is disposed on each side of the workpiece 300, a through hole 410 having the same diameter as the assembly hole 310 is formed in the center of the auxiliary plate 400, and the auxiliary plates 400 can protect the hole wall of the assembly hole 310 from deformation due to stress during the process of drawing the mandrel 100 out of the workpiece 300, thereby ensuring the processing quality of the workpiece 300.

In order to verify the processing effect of the extrusion device of the embodiment, ABAQUS finite element simulation analysis software is used to establish a three-dimensional finite element simulation analysis model of the mandrel 100, the support bar 200 and the workpiece 300, wherein the workpiece 300 is a TC4 titanium alloy perforated structural member, the size is 60mm × 60mm × 10mm, the diameter of a central hole is 12.12mm, the number of slits of the slit extrusion mandrel 100 is 4, the width of the slits is 0.8mm, the diameter of the working ring 1111 is 12.173mm, and a hole extrusion strengthening process simulation with a relative extrusion amount of 5% is performed. In the hole extrusion strengthening simulation analysis model, material properties, grid division conditions, boundaries and constraint conditions are the same, the number of the working rings 1111 of the extrusion core rod 100 is only changed, and the influence of extrusion times on the residual stress field formed on the hole wall of the porous structural part is contrastively analyzed.

After the hole extrusion strengthening, residual compressive stresses in the radial direction, the tangential direction and the plate thickness direction are formed on the hole wall of the assembly hole 310, and the influence of the tangential residual stresses on the performance of the workpiece 300 is the largest, so that only the tangential residual stresses formed at different positions on the hole wall of the assembly hole 310 are analyzed.

Tangential residual stresses of different positions of the hole walls of the mandrel 100 and the assembly hole 310 are extracted, and the hole wall of the assembly hole 310 is divided into three uniform layers, namely a hole wall extrusion layer, a hole wall middle layer and a hole wall extrusion layer.

As can be seen from fig. 7 to 9, the compressive stress field formed by the hole wall extrusion layer is smaller than that of the intermediate layer and the extrusion layer for the same hole extrusion strengthening times and the same distance from the hole wall. The change trend of the residual stress field formed by the hole wall intermediate layer and the extruded layer is the same along with the gradual increase of the distance from the hole wall. The depth of residual compressive stress field layers formed by the hole wall extrusion layer, the middle layer and the extrusion layer is not changed when the hole wall extrusion strengthening times are different, but the surface residual compressive stress and the maximum residual compressive stress of the hole wall extrusion layer are obviously improved, and the residual compressive stress field formed by the hole wall middle layer and the extrusion layer does not change obviously. Because the residual compressive stress field formed by the hole wall extrusion layer is smaller than that of the middle layer and the extrusion layer under the condition of the same extrusion strengthening times, when the workpiece 300 bears external load, fatigue cracks are easily generated in the hole wall extrusion layer. By continuously and repeatedly extruding and strengthening the hole wall of the assembly hole 310, the residual compressive stress on the surface of the hole wall of the extrusion layer is obviously improved, and the maximum residual compressive stress of the extrusion layer is increased, so that the fatigue strength can be improved and the service life can be prolonged by reasonably and repeatedly extruding and strengthening the workpiece 300.

Further, in order to verify that the structure of the pressing apparatus of the present embodiment is optimal for processing the workpiece 300, the present embodiment also performs simulation analysis on two other different conditions by using ABAQUS finite element simulation analysis software, so as to compare with the results of the pressing apparatus described above. The above case is defined as case one, and the other two cases are as follows:

case two: the distance between two adjacent working rings 1111 on the mandrel 100 is 10mm, the thickness of the workpiece 300 is less than 10mm, one working ring 1111 is extruded, and after the hole wall of the assembly hole 310 rebounds, the other working ring 1111 starts to be extruded and strengthened.

Case three: the distance between two adjacent working rings 1111 on the mandrel 100 is 24mm, and a transition structure is arranged between the working rings 1111 and the working part 111, so that the working rings 1111 and the working part 111 are in uniform transition.

The tangential residual stresses at different positions of the wall of the pilot hole 310 of the mandrel 100 in the above three cases were extracted, and the results shown in fig. 10 to 12 were obtained.

As can be seen from fig. 10 to 12, after the mandrel bar 100 for three cases performs extrusion strengthening on the pilot hole 310, the residual stress field formed by the hole wall of the hole-wall extrusion layer is larger than that formed by the middle layer and the extrusion layer. Because the core rod 100 in the three cases is only different in structural form, and the diameters of the working rings 1111 are the same, the depths of residual compressive stress fields formed by the hole wall extrusion layer, the hole wall intermediate layer and the hole wall extrusion layer after hole extrusion strengthening are the same, but the surface residual compressive stress and the maximum residual compressive stress formed by the hole wall extrusion layer and the hole wall extrusion layer after extrusion strengthening of the assembly hole 310 in the first case are obviously greater than those in the second case and the third case.

Because the residual stress field formed by the squeezed-in end of the hole wall of the assembly hole 310 is smaller than that of the intermediate layer and the squeezed-out layer, when the workpiece 300 is subjected to an external alternating load, the squeezed-in layer of the hole wall is firstly subjected to fatigue failure. The surface residual compressive stress and the maximum residual compressive stress formed by the hole wall extrusion layer after the extrusion strengthening of the assembly hole 310 in the case one are more remarkable than those in the case two and the case three, so that the hole extrusion strengthening effect in the case one is better than that in the case two and the case three.

It is obvious that the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, rearrangements and substitutions will now occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. An extrusion apparatus, comprising:

a mandrel (100), one end of which is a working end (110), wherein a mounting hole (115) is formed in the axial center of the working end (110), a plurality of working rings (1111) are convexly arranged at intervals in the circumferential direction of the free end of the working end (110), the diameter of each working ring (1111) is larger than the diameter of an assembling hole (310) of a workpiece (300), a pressing seam (114) is formed in the hole wall of each mounting hole (115) along the axial direction of the mandrel (100) so that the diameter of each working ring (1111) can be reduced, and the workpiece (300) can be sleeved on the working end (110);

a support rod (200) inserted in the mounting hole (115) to limit the size of the diameter of the work ring (1111).

2. Extrusion apparatus according to claim 1, wherein the working end (110) comprises:

a working section (111), the working ring (1111) being provided in a circumferential direction of the working section (111);

the workpiece (300) penetrates through the working part (111) and is sleeved on the placing part (112); and

the diameter of the working part (111) is larger than that of the placing part (112), and the transition part (113) is located between the working part (111) and the placing part (112) and is uniformly transited from the working part (111) to the placing part (112).

3. Press according to claim 2, wherein the free end of the working portion (111) is tapered in diameter to provide a mounting guide for the workpiece (300).

4. Extrusion apparatus according to claim 2, characterized in that transition fillets (1112) are provided between the working ring (1111) and the working portion (111).

5. Extrusion apparatus according to claim 1, characterized in that the distance between two adjacent working rings (1111) is smaller than the thickness of the workpiece (300).

6. Extrusion apparatus according to claim 2, wherein the extrusion slit (114) has a pilot hole (1141) at its end.

7. Extrusion apparatus according to claim 1, wherein the ratio between the length of the extrusion slit (114) and the diameter of the mounting hole (115) is less than 7.

8. Extrusion apparatus according to any of claims 1 to 7, wherein the support bar (200) has one end with a decreasing diameter.

9. Extrusion apparatus according to any of claims 1-7, wherein the length of the support bar (200) is longer than the depth of the mounting hole (115).

10. The extrusion apparatus of any one of claims 1 to 7, further comprising:

two auxiliary plates (400), wherein one auxiliary plate (400) is arranged on each of the two workpieces (300), and a through hole (410) with the same diameter as that of the assembly hole (310) is formed in the center of each auxiliary plate (400).

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