CN111635984A - A hand-held tension-torsion coupling cold extrusion strengthening device and strengthening method for holes - Google Patents

Abstract

The invention discloses a hand-held tension-torsion coupling cold extrusion strengthening device for holes and a strengthening method, comprising a mandrel, a mandrel connector, a driving screw, a jacket, an outer hexagonal screw and a locking cover; a threaded end of the mandrel It passes through the jacking head and is threadedly connected to one end of the mandrel connector; the other end of the mandrel connector is threadedly connected to the driving screw; ; The cylindrical end of the outer hexagonal screw is matched with the small gap of the hole wall in the stepped hole of the outer casing; the threaded connection between the locking cover and the outer casing limits the outer hexagonal screw in the stepped hole of the outer casing. The invention provides a fatigue strengthening device with small volume, simple structure and low economic cost for small batches and poor openness of aircraft connecting holes, and effectively solves the problem that the current cold extrusion strengthening device adopts hydraulic pressure as tensile power, and the structural volume Huge, complex, and expensive problems.

Description

A hand-held tension-torsion coupling cold extrusion strengthening device and strengthening method for holes

technical field

The invention belongs to the technical field of machining, and in particular relates to a hand-held tension-torsion coupling cold extrusion strengthening device for holes and a strengthening method.

Background technique

In the process of aircraft manufacturing, a large number of mechanical connection structures exist. The amount of fasteners for an aircraft can reach hundreds of thousands to millions, and it will still not be able to be replaced in the foreseeable future. However, the aircraft structure is often subjected to fatigue loads during the service process. The mechanical connection holes destroy the continuity of the overall structure, cause stress concentration, and are prone to initial damage. It is a typical fatigue risk point of the overall structure. Therefore, how to improve the fatigue performance of mechanical connection holes, especially key load-bearing connection holes, has always been an important research content to improve the reliability of aircraft.

Cold extrusion strengthening under suitable strengthening amount can significantly improve the fatigue performance of mechanical connection holes, and has many advantages such as no change of structural size and no extra weight. Usually cold extrusion strengthening is divided into direct cold extrusion and cold extrusion with bushing: direct cold extrusion directly extrudes the connecting hole wall through the mandrel to force it to undergo plastic deformation, and the microstructure of the hole wall material is improved after extrusion. The hole wall forms beneficial residual compressive stress, thereby improving the fatigue performance of the hole; cold extrusion with bushing (such as slotted bushing, pressing bushing, etc.) Pressing the bushing, the bushing expands and then further squeezes the hole wall, which can effectively avoid the damage of the hole wall and improve the uniformity of residual stress distribution. No matter direct cold extrusion or cold extrusion with bushing, cold extrusion strengthening equipment is required to provide tensile force to the mandrel during the strengthening process. The current cold extrusion strengthening device usually uses hydraulic pressure as the stretching power, the structure is bulky, the system is complicated, and usually expensive The invention patent with the machine and patent number of 201910749455.6 discloses a deep-hole ultrasonic vibration impact strengthening device and method. Although these inventions can achieve high-quality cold extrusion strengthening of holes, in practice, there are many assembly environments with poor openness in aircraft manufacturing. Obviously, the strengthening equipment with large structures cannot be effectively used. In addition, in the process of aircraft maintenance, the number of holes to be strengthened is usually small and the structural openness is poor. Considering the cost, expensive large-scale strengthening equipment is not suitable. The invention with the patent number of 201910637084.2 discloses a rotary hole cold extrusion strengthening device and method. Although the invention is significantly smaller than the hydraulic cold extrusion strengthening equipment, it is compared with many narrow operating environments in the aircraft manufacturing process. , the volume is still too large, it is difficult to strengthen, and the structure and operation process of the invention are complicated.

SUMMARY OF THE INVENTION

The purpose of the present invention is to aim at the above-mentioned deficiencies in the prior art, and to provide a hole-hand-held tension-twist coupling cold extrusion strengthening device and strengthening method for the aircraft mechanical connection holes with a small number and poor openness, In order to solve the problems that the current cold extrusion strengthening device uses hydraulic pressure as the stretching power, the structure is bulky, the system is complex, and the price is expensive.

In order to achieve the above object, the technical scheme that the present invention takes is:

A hand-held tension-torsion coupling cold extrusion strengthening device with holes, which comprises a mandrel, a mandrel connector, a driving screw, a jacket, an outer hexagonal screw and a locking cover; the threaded end of the mandrel passes through the jacking head and One end of the mandrel connector is threadedly connected; the other end of the mandrel connector is threadedly connected to the driving screw; The cylindrical end of the casing is matched with the hole wall in the stepped hole of the outer casing with a small gap; and the outer hexagonal screw is restricted in the stepped hole of the outer casing through the threaded connection of the locking cover and the casing.

Preferably, the reinforcing heads of the mandrel are spaced at the same central angle to cut the sector cylindrical surface corresponding to the central angle along the length direction of the mandrel.

Preferably, one end of the cylindrical boss of the mandrel connector is provided with an external thread, and the other end is provided with a central internal thread hole.

Preferably, the mandrel connector is threadedly connected to the drive screw through the cylindrical boss end, and is threadedly connected to the mandrel through the central inner threaded hole.

Preferably, one end of the driving screw has an internal threaded hole; the other end is in the shape of an inner hexagon, and the outer hexagonal shape is a circular boss with a hexagonal boss, and a left-handed internal threaded hole is provided in the center.

A hand-held tension-torsion coupling cold extrusion strengthening method for holes, comprising:

A. Cold extrusion strengthening of connecting holes without bushings;

B. Strengthen the connection hole with bushing by cold extrusion.

Preferably, the cold extrusion strengthening of the connecting hole without bushing in A includes:

A1. The threaded end of the mandrel passes through the hole to be strengthened, and then passes through the central through hole of the jacking head and is threadedly connected to the mandrel connector;

A2. Connect the mandrel connector to the drive screw thread, and the jacking head to the outer casing thread;

A3. Use an outer hexagonal wrench to hold the outer hexagonal screw, keep the outer hexagonal screw from rotating in the circumferential direction, insert the inner hexagonal wrench into the inner hexagonal end of the driving screw, rotate the inner hexagonal wrench slowly at a constant speed, and the rotation of the driving screw drives the axial direction of the mandrel Linear motion and circumferential rotational motion;

A4. After the strengthening head of the mandrel completely passes through the hole, a tension-torsion coupling cold pressure strengthening is completed, the driving screw is reversely rotated to return the driving screw to the initial position, and the mandrel is removed to complete a strengthening;

A5. Repeat steps A1 to A4 for the next reinforcement.

Preferably, the cold extrusion strengthening of the connecting hole with the bushing in B includes:

B1. The threaded end of the mandrel is threadedly connected to the mandrel connector, the mandrel connector is threadedly connected to the driving screw, and the jacking head is threadedly connected to the outer casing;

B2. Set the bushing on the mandrel, pass the head of the mandrel through the hole to be strengthened, and slide the bushing into the hole to be strengthened;

B3. Insert the hexagonal wrench into the hexagonal end of the driving screw, keep the circumferential direction of the driving screw stationary, use the hexagonal wrench to rotate the outer hexagonal screw, and the driving screw drives the mandrel to move linearly. When the bushing is squeezed and deformed by the mandrel, it is fixed in After the hole wall, stop rotating the outer hexagonal screw;

B4. Keep the outer hexagonal rotary member static in the circumferential direction, rotate the driving screw, drive the axial linear motion and circumferential rotational motion of the mandrel, and perform the pull-rotation coupling cold extrusion strengthening on the hole;

B5. After the strengthening head of the mandrel completely passes through the hole, a tension-torsion coupling cold pressure strengthening is completed, and the driving screw is rotated in the reverse direction to make the driving screw return to the initial position, that is, a strengthening is completed;

B6. Repeat steps B1 to B5 for the next reinforcement.

The hand-held tension-torsion coupling cold extrusion strengthening device and strengthening method for holes provided by the present invention have the following beneficial effects:

The invention realizes the direct hand-held tension-torsion coupled cold extrusion of the hole and the tension-torsion coupled hand-held cold extrusion with the bushing hole through the mutual cooperation of the driving screw and the outer hexagonal screw, which is suitable for small batches and poor openness. The aircraft connecting hole provides a fatigue strengthening device with small volume, simple structure and low economic cost, which effectively solves the problems that the current cold extrusion strengthening device uses hydraulic pressure as the tensile power, the structure is bulky, the system is complex, and the price is expensive. .

In addition, the present invention reduces the strengthening resistance by cutting the cylindrical surface of the strengthening head of the mandrel with the same central angle, thereby reducing the difficulty of strengthening and the degree of damage to the hole wall; the uniformity of stress distribution around the hole is improved by means of tension and torsion coupling, and there are It is beneficial to improve the fatigue life-enhancing effect of cold extrusion.

Description of drawings

FIG. 1 is a front view and a cross-sectional view of a hand-held tension-twist coupled cold extrusion strengthening device for holes.

Figure 2 is an isometric view of a mandrel of a hand-held tension-torsion coupled cold extrusion strengthening device for holes.

Figure 3 is an isometric view of the jacking head of the hand-held tension-torsional coupled cold extrusion strengthening device for the hole.

Figure 4 is an isometric view of a mandrel connector of a hand-held tension-torsional coupled cold extrusion strengthening device for holes.

Figure 5 is an isometric view of an outer hexagonal screw of a hand-held tension-torsion coupled cold extrusion strengthening device for holes.

Among them, 1. mandrel; 2. jacking head; 3. mandrel connector; 4. jacket; 5. outer hexagonal screw; 6. locking cover; 7. driving screw.

Detailed ways

The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Such changes are obvious within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions and creations utilizing the inventive concept are within the scope of protection.

According to an embodiment of the present application, referring to FIG. 1 , the hand-held tension-torsion-coupling cold extrusion strengthening device for holes in this solution includes a mandrel 1 , a jacking head 2 , a mandrel connector 3 , a driving screw 7 , and a jacket 4 , Outer hexagon screw 5 and locking cover 6.

The above components will be described in detail below:

Referring to Figure 2, mandrel 1, the reinforcing head of the mandrel 1 is spaced at the same central angle and the cylindrical surface is cut flat to reduce the strengthening resistance, and is used to squeeze the hole to be strengthened.

Referring to Figure 4, the mandrel connector 3 is used for the transition connection between the mandrel 1 and the driving screw 7, and is flange-like. According to the different external thread sizes of different types of mandrels 1, the mandrel connector 3 is designed into multiple models, each model only has a different size of the central internal thread hole, and is matched with different types of mandrels 1.

The driving screw 7 is used to drive the linear and rotational movement of the mandrel 1, with a left-handed external thread, one end has an internal threaded hole, and the other end is in the shape of an internal hexagon; the external hexagonal screw 5 is used to drive the linear movement of the mandrel 11, which is A round boss with a hexagonal boss with a left-hand female threaded hole in the center.

Outer cover 4, used to provide hand-holding, has a stepped hole in the center and internally threaded holes at both ends.

The locking cover 6 is used to cover the outer hexagonal screw 5 in the outer casing 4, with a central through hole and an external thread at the small diameter end.

Referring to Figure 3, the jacking head 2, used for jacking the workpiece, has a central through hole, and the cylindrical boss at the connecting end has an external thread.

The connection relationship between the above components is:

The threaded end of the mandrel 1 passes through the jacking head 2 and is threadedly connected to one end of the mandrel connector 3, the other end of the mandrel connector 3 is threadedly connected to the drive screw 7, and the periphery of the drive screw 7 is threadedly connected to the outer casing 4.

Referring to FIG. 5 , after the central through hole of the jacking head 2 passes through the mandrel 1 , it is threadedly connected to the outer casing 4 . There is a stepped hole in the center of the outer casing 4, and both ends of the stepped hole are internally threaded holes. Connection, the outer hexagonal screw 5 is limited to the stepped hole of the outer casing 4.

According to an embodiment of the present application, a hand-held tension-torsion coupling cold extrusion strengthening method for holes, comprising:

A. Cold extrusion strengthening of connecting holes without bushings;

B. Strengthen the connection hole with bushing by cold extrusion.

Among them, the cold extrusion strengthening of the connecting hole without bushing in A includes:

Step A1, the threaded end of the mandrel 1 passes through the hole to be strengthened, and then passes through the central through hole of the jacking head 2 to be threadedly connected to the mandrel connector 3;

Step A2, screw the mandrel connector 3 with the drive screw 7, and screw the jacking head 2 with the jacket 4;

Step A3: Use an external hexagonal wrench to hold the external hexagonal screw 5, keep the external hexagonal screw 5 from rotating in the circumferential direction, insert the internal hexagonal wrench into the internal hexagonal end of the driving screw 7, rotate the internal hexagonal wrench slowly at a constant speed, and the driving screw 7 rotates Drive the mandrel 1 to move axially linearly and rotate in the circumferential direction;

Step A4: After the strengthening head of the mandrel 1 completely passes through the hole, a tension-torsion coupling cold pressure strengthening is completed, the driving screw 7 is reversely rotated to return the driving screw 7 to the initial position, and the mandrel 1 is removed to complete a strengthening;

Step A5: Repeat Step A1 to Step A4 for the next reinforcement.

The cold extrusion strengthening of the connecting hole with the bushing in B includes:

Step B1, the threaded end of the mandrel 1 is threadedly connected to the mandrel connector 3, the mandrel connector 3 is threadedly connected to the driving screw 7, and the jacking head 2 is threadedly connected to the outer sleeve 4;

Step B2, set the bushing on the mandrel, pass the head of the mandrel through the hole to be strengthened, and slide the bushing into the hole to be strengthened;

Step B3: Insert the hexagonal wrench into the hexagonal end of the driving screw 7, keep the driving screw 7 stationary in the circumferential direction, use the external hexagonal wrench to rotate the external hexagonal screw 5, and the driving screw 7 drives the mandrel 1 to move linearly, and when the bushing is cored After the rod 1 is squeezed and deformed and fixed on the hole wall, stop rotating the outer hexagonal screw 5;

Step B4, keeping the outer hexagonal screw 5 stationary in the circumferential direction, rotating the driving screw 7, driving the axial linear motion and circumferential rotational motion of the mandrel, and performing pulling and rotating coupling cold extrusion strengthening on the hole;

Step B5, when the strengthening head of the mandrel 1 completely passes through the hole, complete a tension-torsion coupling cold pressure strengthening, and reversely rotate the driving screw 7 to make the driving screw 7 return to the initial position, that is, a strengthening is completed;

Step B6: Repeat Step B1 to Step B5 for the next strengthening.

The present invention realizes the direct hand-held tension-torsion coupled cold extrusion of the hole and the tension-torsion coupled hand-held cold extrusion with a bushing hole through the mutual cooperation of the driving screw 7 and the outer hexagonal screw 5, which is a small batch, open The aircraft connection hole with poor performance provides a fatigue strengthening device with small volume, simple structure and low economic cost.

In addition, the present invention cuts the cylindrical surface of the reinforcement head of the mandrel 1 at intervals with the same central angle, thereby reducing the reinforcement resistance, the difficulty of reinforcement and the degree of damage to the hole wall; the uniformity of stress distribution around the hole is improved by means of tension-torsion coupling, It is beneficial to improve the fatigue life-enhancing effect of cold extrusion.

Although the specific embodiments of the invention have been described in detail with reference to the accompanying drawings, they should not be construed as limiting the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative work still belong to the protection scope of this patent.

Claims (8)

1. A hand-held tension-torsion coupling cold extrusion strengthening device of a hole is characterized in that: comprising a mandrel, a mandrel connector, a driving screw, an outer sleeve, an outer hexagonal screw and a locking cover; the thread of the mandrel is The end passes through the jacking head and is threadedly connected to one end of the mandrel connector; the other end of the mandrel connector is threadedly connected to the drive screw; Both ends are internally threaded holes; the cylindrical end of the outer hexagonal screw is matched with the hole wall in the stepped hole of the outer casing with a small gap; and the threaded connection between the locking cover and the outer casing limits the outer hexagonal screw to the outer casing inside the step hole. 2 . The hand-held tension-torsion coupling cold extrusion strengthening device for holes according to claim 1 , wherein the reinforcing head of the mandrel is spaced at the same central angle, and the sector cylinder corresponding to the central angle is cut along the length direction of the mandrel. 3 . noodle. 3 . The hand-held tension-torsion coupling cold extrusion strengthening device for holes according to claim 1 , wherein the cylindrical boss at one end of the mandrel connector has an external thread, and the other end has a central internal thread hole. 4 . 4 . The hand-held tension-torsion coupling cold extrusion strengthening device for holes according to claim 3 , wherein the mandrel connector is threadedly connected to the drive screw through the cylindrical boss end, and is connected to the mandrel through the central inner threaded hole. 5 . Threaded connection. 5. The hand-held tension-torsion coupling cold extrusion strengthening device for holes according to claim 1, characterized in that: one end of the driving screw has an inner threaded hole; The circular boss of the table has a left-handed internal thread hole in the center. 6. A hand-held tension-torsion coupling cold extrusion strengthening method according to any one of claims 1-5, characterized in that, comprising: A. Cold extrusion strengthening of connecting holes without bushings; B. Strengthen the connection hole with bushing by cold extrusion. 7 . The hand-held tension-torsion coupling cold extrusion strengthening method for holes according to claim 6 , wherein the cold extrusion strengthening of the connecting holes without bushings in said A comprises: 8 . A1. The threaded end of the mandrel passes through the hole to be strengthened, and then passes through the central through hole of the jacking head and is threadedly connected to the mandrel connector; A2. Connect the mandrel connector to the drive screw thread, and the jacking head to the outer casing thread; A3. Use an outer hexagonal wrench to hold the outer hexagonal screw, keep the outer hexagonal screw from rotating in the circumferential direction, insert the inner hexagonal wrench into the inner hexagonal end of the driving screw, rotate the inner hexagonal wrench slowly at a constant speed, and the rotation of the driving screw drives the axial direction of the mandrel Linear motion and circumferential rotational motion; A4. After the strengthening head of the mandrel completely passes through the hole, a tension-torsion coupling cold pressure strengthening is completed, the driving screw is reversely rotated to return the driving screw to the initial position, and the mandrel is removed to complete a strengthening; A5. Repeat steps A1 to A4 for the next reinforcement. 8 . The hand-held tension-torsion coupling cold extrusion strengthening method for holes according to claim 6 , wherein the cold extrusion strengthening of the connecting holes with bushings in said B comprises: B1. The threaded end of the mandrel is threadedly connected to the mandrel connector, the mandrel connector is threadedly connected to the driving screw, and the jacking head is threadedly connected to the outer casing; B2. Set the bushing on the mandrel, pass the head of the mandrel through the hole to be strengthened, and slide the bushing into the hole to be strengthened; B3. Insert the hexagonal wrench into the hexagonal end of the driving screw, keep the driving screw circumferentially stationary, use the external hexagonal wrench to rotate the outer hexagonal screw, and the driving screw drives the mandrel to move linearly. When the bushing is squeezed and deformed by the mandrel, it is fixed in After the hole wall, stop rotating the outer hexagonal screw; B4. Keep the outer hexagonal rotary member static in the circumferential direction, rotate the driving screw, drive the axial linear motion and circumferential rotational motion of the mandrel, and carry out the pull-rotation coupling cold extrusion strengthening for the hole; B5. After the strengthening head of the mandrel completely passes through the hole, a tension-torsion coupling cold pressure strengthening is completed, and the driving screw is rotated in the reverse direction to make the driving screw return to the initial position, that is, a strengthening is completed; B6. Repeat steps B1 to B5 for the next reinforcement.

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