阅读说明：本技术 半空心螺纹铆钉及其单边连接方法 (Semi-hollow threaded rivet and unilateral connection method thereof ) 是由 杨炳鑫 李永兵 马运五 山河 雷海洋 于 2020-04-01 设计创作，主要内容包括：一种半空心螺纹铆钉,包括：一体成形的铆钉头和空心结构的铆钉体,该铆钉体从下而上依次包括：流钻部、攻丝部和螺纹部,其中：流钻部和攻丝部位于空心结构的外缘,流钻部的底端为楔形锥角。本发明通过攻丝与拧紧实现螺纹连接,最终形成螺纹-固相复合连接；铆接完成后,铆钉尖端未刺穿下层板材,保证了接头的密封性,提升抗腐蚀能力；由于下层板无尖锐凸起,使该工艺可以用于型材外其他类型的连接,扩大了工艺的应用范围。(A semi-hollow threaded rivet comprising: integrative shaping rivet head and hollow structure's rivet body, this rivet body from down and upward include in proper order: a flow drill portion, a thread forming portion, and a threaded portion, wherein: the flow drilling part and the tapping part are positioned at the outer edge of the hollow structure, and the bottom end of the flow drilling part is provided with a wedge-shaped taper angle. The invention realizes the threaded connection through tapping and screwing, and finally forms the thread-solid phase composite connection; after riveting is finished, the tip of the rivet does not pierce through the lower-layer plate, so that the sealing property of the joint is ensured, and the corrosion resistance is improved; because the lower plate has no sharp bulge, the process can be used for other types of connection outside the section bar, and the application range of the process is expanded.)

1. A semi-hollow threaded rivet, comprising: integrative shaping rivet head and hollow structure's rivet body, this rivet body from down and upward include in proper order: a flow drill portion, a thread forming portion, and a threaded portion, wherein: the flow drilling part and the tapping part are positioned at the outer edge of the hollow structure, and the bottom end of the flow drilling part is provided with a wedge-shaped taper angle.

2. A semi-hollow threaded rivet according to claim 1, in which the rivet head is provided coaxially with a locating hole at its upper end and with a recessed chip-collecting groove at its lower end from the inside to the outside and with an integrally attached bearing surface.

3. A semi-hollow threaded rivet according to claim 2, in which the locating hole is in the form of an inverted truncated cone, the periphery of which is provided with a driving structure; the driving structure is in a quadrangle quincuncial shape, a hexagon shape or consists of a plurality of wedge-shaped tooth structures, and the whole body is designed to be a bulge or a groove.

4. A semi-hollow threaded rivet according to claim 1 wherein the heights of the flow drill portion, the tapping portion and the threaded portion are such that: h₁＝K₁H₂，H₁+H₂＝K₂R₁，H₁+H₂+H₃H, wherein: h is the height of the rivet body, H₁Height of the flow-drilling part, H₂Height of the tapping portion, H₃Height of the threaded portion, R₁Is the outside diameter of the rivet body, K₁And K₂Is a correction factor.

5. A semi-hollow threaded rivet according to claim 1 or 4, in which the height of the rivet body is such that: h ═ t₁+Kt₂-0.2, wherein: h is the rivet body height, t₁Thickness of upper connecting member, t₂The thickness of the lower layer connecting piece is shown, and K is a correction coefficient.

6. A semi-hollow threaded rivet according to claim 1, in which the depth of the hollow formation of the rivet body is such that:wherein: h is the depth of the hollow structure, t is the total thickness of the parts to be connected, delta is the elongation of the lower layer of the connecting part, R₁Is the outside diameter of the rivet body, R₂Is the inner diameter of the rivet body, K₃Is a correction factor.

7. A single-side connection method of a semi-hollow threaded rivet according to any one of claims 1 to 6, characterized in that a to-be-connected piece is pressed by a blank holder, the rivet and a driving head matched with the rivet are assembled and then placed on an upper-layer connecting piece and are coaxial with the blank holder, and the rivet and the to-be-connected piece form a thread-solid phase composite connection without piercing the to-be-connected piece sequentially through a penetrating stage, a tapping stage and a screwing stage;

the penetration stage is specifically as follows: the driving head drives the rivet to penetrate into the upper layer connecting piece in a high-speed rotation and low-speed feeding mode until the flow drilling part of the rivet completely enters the to-be-connected piece so as to form solid phase connection between the inner side and the outer side of the rivet, and at the moment, the to-be-connected piece is softened by friction heat generation of the flow drilling part and the lower layer connecting piece generates plastic flow;

the tapping stage specifically comprises: the driving head drives the rivet to reduce the rotating speed, and the tapping part is contacted with the to-be-connected piece to form threads;

the tightening stage is specifically as follows: the driving head drives the rivet to further reduce the rotating speed, and the threads on the outer side of the rivet body are sequentially meshed with the to-be-connected piece in a threaded mode until the torque of the driving head reaches a preset value, and then stopping.

8. The single-sided connection method of claim 7, wherein the parts to be connected are two or more layers, wherein: the upper layer connecting piece is a light alloy sheet, a composite material or a steel plate, and the lowest layer connecting piece is a sheet, a light alloy casting or an extruded section.

9. The single-sided connection method of claim 7, wherein the upper connection member is a steel plate having a strength of more than 400MPa or a thickness of more than 1.5mm, and a preformed hole is formed to prevent the rivet from being melted due to an excessively high hardness of the plate.

Technical Field

The invention relates to a technology in the field of unilateral connection, in particular to a semi-hollow threaded rivet and a unilateral connection method thereof.

Background

Light-weight structures such as light alloy castings and extruded profiles are widely applied to the manufacture of shells of automobiles, locomotives, rockets and the like because of the obvious advantage of the light-weight structures in comparison with plates in the aspect of thin-wall structural rigidity. However, when connecting closed/semi-closed profiles or light alloy castings, due to space constraints, a double-sided connection is difficult to achieve and requires the use of a single-sided connection technique. In the existing unilateral connection technology, a through hole needs to be prefabricated on a connecting plate in the core-pulling riveting technology, so that the production tact is reduced, difficulty is brought to production due to the high requirement on the coaxiality of the prefabricated hole and a rivet, and the metal scraps generated by the prefabricated hole can bring discomfort to a user. The flow drilling and riveting technology does not need to prefabricate holes, but because the screws need to penetrate all connecting plates, the sealing performance of the joint is reduced, and the corrosion resistance of the joint is reduced; the light alloy softened in the perforation process is squeezed into the plates, so that gaps appear in the joints; the screw tail end and the thread forming area have no practical effect on the connection strength, the length and the weight of the screw are additionally increased, the screw is not beneficial to light weight, and the application of the screw in a smaller cavity structure is limited.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a semi-hollow threaded rivet and a unilateral connection method thereof.

The invention is realized by the following technical scheme:

the invention relates to a semi-hollow threaded rivet, comprising: integrative shaping rivet head and hollow structure's rivet body, this rivet body from down and upward include in proper order: a flow drill portion, a thread forming portion, and a threaded portion, wherein: the flow drill portion and the tapping portion are located at the outer edge of the hollow structure.

The heights of the flow drilling part, the tapping part and the thread part simultaneously satisfy the following conditions: h₁＝K₁H₂，H₁+H₂＝K₂R₁，H₁+H₂+H₃H, wherein: h is the height of the rivet body, H₁Height of the flow-drilling part, H₂Height of the tapping portion, H₃Height of the threaded portion, R₁Is the outside diameter of the rivet body, K₁And K₂Is a correction factor; the integrated design of the flow drilling part, the tapping part and the thread part realizes the integration of drilling, tapping and connecting operations, and the thread-solid phase composite connecting joint is obtained after the process is finished.

The correction coefficient K₁Preferably [1.2,2.0 ]]，K₂Preferably [0.5,0.8 ]]。

The height of the rivet body satisfies: h ═ t₁+Kt₂-0.2, wherein: h is the rivet body height, t₁Thickness of upper connecting member, t₂The thickness of the lower layer connecting piece is shown, and K is a correction coefficient; by optimizing the height of the rivet body, the extrusion amount of a workpiece material in the construction process is accurately controlled, and the lower layer plate is ensured not to be penetrated, and meanwhile, a longer connection length is provided.

The correction factor K is preferably [1.5,2.0 ].

The depth of the hollow structure of the rivet body satisfies the following requirements:wherein: h is the depth of the hollow structure, t is the total thickness of the parts to be connected, delta is the elongation of the lower layer of the connecting part, R₁Is the outside diameter of the rivet body, R₂Is the inner diameter of the rivet body, K₃Is a correction factor; flow space is provided for the extruded workpiece material while reducing the weight of the joint.

The correction coefficient K₃Preferably [0.01,0.04 ]]。

The invention relates to a single-side connection method of a semi-hollow threaded rivet.

The penetration stage is specifically as follows: the driving head drives the rivet to penetrate into the upper layer connecting piece in a high-speed rotation and low-speed feeding mode until the flow drilling part of the rivet completely enters the to-be-connected piece so as to form solid phase connection between the inner side and the outer side of the rivet, and at the moment, the to-be-connected piece is softened by friction heat generation of the flow drilling part and the lower layer connecting piece generates plastic flow.

The tapping stage specifically comprises: the driving head drives the rivet to reduce the rotating speed, and the tapping part is contacted with the to-be-connected piece to form threads.

The tightening stage is specifically as follows: the driving head drives the rivet to further reduce the rotating speed, and the threads on the outer side of the rivet body are sequentially meshed with the to-be-connected piece in a threaded mode until the torque of the driving head reaches a preset value, and then stopping.

Technical effects

The invention integrally solves the problems in the prior art that: the flowing drilling and riveting technology needs to penetrate all connecting plates to reduce the sealing performance of the joint, so that the corrosion resistance of the joint is reduced; the light alloy softened in the perforation process is squeezed into the plates, so that gaps appear in the joints; the screw tail end and the thread forming area have no practical effect on the connection strength, the length and the weight of the screw are additionally increased, the screw is not beneficial to light weight, and a plurality of problems such as application of the screw in a smaller cavity structure are limited.

Compared with the prior art, the flow drill, the tapping and the thread are sequentially designed on the outer wall of the semi-hollow rivet from bottom to top, the thread connection is realized through tapping and screwing, and finally the thread-solid phase composite connection is formed; after riveting is finished, the tip of the rivet does not pierce through the lower-layer plate, so that the sealing property of the joint is ensured, and the corrosion resistance is improved; because the lower layer plate has no sharp bulge, the process can be used for connecting other types outside the section bar, and the application range of the process is expanded; the semi-hollow structural design makes the rivet body grow thick on the one hand to transmit bigger moment of torsion, provide higher screw thread load, on the other hand has alleviateed the quality of rivet, makes the demand that lightweight production more satisfied of this technology.

Drawings

FIG. 1 is a schematic structural view of the present invention;

in the figure: a is a front view; b is a top view;

FIG. 2 is a schematic structural view of a rivet;

in the figure: a is a schematic illustration of the rivet of example 1; b is a schematic rivet view of example 2; c is a schematic rivet view of example 3;

FIG. 3 is a diagram showing the application process of example 1;

in the figure: a is a schematic diagram of step 1; b is a schematic diagram of step 2; c is a schematic diagram of step 3; d is a schematic diagram of step 4; e is a schematic representation of the thread-solid phase composite joint formed in example 1;

FIG. 4 is a diagram showing the application of example 2;

in the figure: a is a schematic diagram of step 1; b is a schematic diagram of step 2; c is a schematic diagram of step 3; d is a schematic diagram of step 4; e is a schematic representation of the thread-solid phase composite joint formed in example 2;

FIG. 5 is a diagram showing the application process of example 3;

in the figure: a is a schematic diagram of step 1; b is a schematic diagram of step 2; c is a schematic diagram of step 3; d is a schematic diagram of step 4; e is a schematic representation of the thread-solid phase composite joint formed in example 3;

in the figure: the rivet comprises a rivet 1, a driving head 2, a blank holder 3, a to-be-connected part 4, a prefabricated hole 5, a rivet head 101, a rivet body 102, a positioning hole 103, a driving structure 104, a chip collecting groove 105, a bearing surface 106, a threaded part 107, a tapping part 108, a flow drilling part 109, a taper angle 110, an upper layer connecting part 401, a middle layer connecting part 402 and a lower layer connecting part 403.

Detailed Description

Example 1

The to-be-connected member 4 employed in the present embodiment includes: an upper layer connecting piece 401 with the mark AA6061-T6 and a lower layer connecting piece 403 with the mark 6005A-T6; the thickness of the upper layer connecting piece 401 is 2.5 mm; the thickness of the lower connecting piece 403 is 4.0 mm.

As shown in fig. 1, the present embodiment relates to a half hollow threaded rivet comprising: a rivet head 101 and a rivet body 102 are integrally connected.

The height of the rivet 1 is 10.6 mm; the height of the rivet head 101 is 2.0mm, and the diameter of the rivet head is 10.0 mm.

The center of the upper end of the rivet head 101 is provided with a positioning hole 103, and six driving structures 104 which are uniformly distributed and are in a wedge-shaped tooth shape are arranged outside the positioning hole 103.

The tooth depth of the driving structure 104 is 1.2 mm.

The lower end of the rivet head 101 is provided with an integrated concave chip collecting groove 105 and a supporting surface 106 from inside to outside, wherein: the chip pockets 105 are connected to the rivet body 102.

The chip collection groove 105 and the support surface 106 are both roughened surfaces that are sanded to maintain good sealing with the upper connecting member 401, and the chip collection groove 105 is sized according to the size of the rivet 1.

The inner diameter of the chip collecting groove 105 is 7.0mm, the outer diameter of the chip collecting groove is 8.5mm, and the deepest height of the chip collecting groove is 0.5 mm.

The rivet body 102 sequentially comprises from top to bottom: a threaded portion 107, a tapped portion 108, and a flow drilling portion 109, wherein: the hardness of the flow drilling portion 109 is greater than that of the threaded portion 107 and the tapping portion 108 to facilitate the penetration of the flow drilling into the member to be connected 4.

The bottom end of the flow drilling portion 109 is provided with a wedge angle 110, the tip of the angle 110 being located between the inner and outer walls of the rivet body 102.

The tapping part 108 is used for machining an internal thread on the inner wall of a hole formed by flow drilling of the member 4 to be connected so as to create a foundation for tightening the threaded part 107 of the rivet 1.

The thread 107 is intended to form a threaded connection with the part 4 to be connected, the thread being provided on the outside and/or inside of the rivet body 102 and being a standard connection thread, a fine triangular thread or a coarse triangular thread.

The thread has the same direction of rotation as the drive structure 104 and is actually a single thread or a multiple thread.

The thread of the thread part 107 described in this embodiment is provided on the outside of the rivet body 102, and the thread is a single thread, and the thread is screwed in the same direction as the rotation direction of the driver 2, as shown in fig. 2 a.

The height of the rivet body 102 is 8.6mm, the inner diameter of the rivet body is 4.2mm, the outer diameter of the rivet body is 7.0mm, and the depth of a lower section hollow structure of the rivet body is 4.8 mm; the height of the thread part 107 is 4.1 mm; the height of the tapping part 108 is 1.5 mm; the height of the flow drilling part 109 is 3.0 mm.

The rivet 1 is made of nickel-based alloy, cobalt-based alloy or boron-treated medium carbon steel.

As shown in fig. 3, the present embodiment relates to a single-side connection method for a half hollow threaded rivet, which specifically includes the following steps:

step 1, preparation stage: the blank holder 3 compresses the to-be-connected piece 4, the driving head 2 is meshed with the driving structure 104 of the rivet 1 to drive the rivet 1 to rotate forwards and backwards at a low speed so as to ensure that the driving head 2 and the driving structure 104 of the rivet 1 form stable matching, and meanwhile, the driving head 2 drives the rivet 1 to feed at a low speed at a position coaxial with the blank holder 3 so that the taper angle 110 of the rivet 1 is in surface contact with the upper-layer connecting piece 401.

Step 2, a penetrating stage: the driving head 2 drives the rivet 1 to feed at the rotation speed of 4000rpm and the speed of 1mm/s, the rivet penetrates into the upper layer connecting piece 401 for 3mm until the flow drilling part 109 of the rivet completely enters the piece 4 to be connected, the upper layer connecting piece 401 is softened by heat generated by the friction of the flow drilling part 109, the lower layer connecting piece 403 generates plastic flow, solid-phase connection is formed between the inner side and the outer side of the rivet 1 and the piece 4 to be connected, and a softening foundation is also created for tapping and screwing.

Step 3, tapping: the driving head 2 is rotated at 2500rpm, fed by 4.5mm, and the tapping portion 108 of the rivet 1 comes into contact with and forms a thread with the member to be connected 4.

Step 4, screwing stage: the driver bit 2 is rotated at 200rpm, the screw portion 107 of the rivet 1 is successively brought into screw engagement with the upper connecting member 401 and the lower connecting member 403, and the driver bit 2 stops when the torque reaches 10N · m.

Step 5, forming a composite joint: the driving head 2 is reversely fed and withdrawn, the supporting surface 106 is pressed with the upper surface of the upper connecting piece 401 to enable burrs and debris to be wrapped in the concave chip collecting groove 105, the pressing effect of the supporting surface 106 prevents the torque in the joint from being attenuated and loosening, and the thread part 107 and the flow drill part 109 of the rivet 1 and the to-be-connected piece 4 form a non-pierced thread-solid phase composite joint.

The diameter of the blank holder 3 is 12mm, and the movement of the blank holder is controlled by a spring mechanism.

The rotating speed of the driving head 2 in the step 3 is lower than that in the step 2 so as to prevent metal chips generated when the threads are meshed; the rotating speed of the driving head 2 in the step 4 is lower than that in the step 3 so as to avoid the damage of the hole wall thread of the to-be-connected piece 4.

Metallographic observation is carried out on the joint, so that good threaded connection is realized between the rivet and the workpiece, and the tip of the rivet is in solid-phase connection with the workpiece and between the two layers of workpieces; the joint is subjected to a tensile-shear test, and the strength of the joint exceeds that of the AA6061-T6 aluminum alloy base metal.

Compared with the existing flowing drilling and riveting process, the joint obtained in the embodiment has the advantages that the corrosion resistance of the joint is obviously improved because the rivet does not pierce through the lower-layer connecting piece; in the embodiment, the threaded connection is formed at the interface with the workpiece, and meanwhile, the friction heat is accumulated through the high-speed rotation of the flow drill part 109, so that the solid-phase connection is formed between the upper and lower plates, and the mechanical property of the joint is improved.

Example 2

As shown in fig. 4, the to-be-connected member 4 employed in the present embodiment includes: an upper layer connector 401, a middle layer connector 402 and a lower layer connector 403; the upper layer connecting piece 401 is 6A01-T5 aluminum alloy with the thickness of 1 mm; the middle layer connecting piece 402 is AZ31B magnesium alloy with the thickness of 1 mm; the lower connecting piece 403 is a 6005A-T6 profile with the thickness of 3.0mm, and the depth of the hollow structure is 18 mm.

Compared with example 1, the height of the rivet 1 of this example is 9.6mm, the inner diameter thereof is 3.6mm, the outer diameter thereof is 6.0mm, and the weight thereof is 2.0 g; the height of the rivet body 102 is 7.6mm, and the depth of the lower section hollow structure is 5.2 mm; the height of the threaded portion 107 is 3.6 mm; the height of the tapping part 108 is 1.5 mm; the height of the flow drilling section 109 is 2.5 mm.

Compared with the embodiment 1, the rivet body 102 of the present embodiment has a plurality of grooves on the inner cavity wall of the lower portion, as shown in fig. 2 b.

Compared with the embodiment 1, in the step 2 of the embodiment, the driving head 2 drives the rivet 1 to feed for 2.5mm at the rotating speed of 3600rpm and the feeding speed of 0.8 mm/s; in step 3, the driving head 2 drives the rivet 1 to feed for 4.0mm at the rotating speed of 2500 rpm; in step 4, the driving head 2 drives the rivet 1 at a rotation speed of 200rpm until the torque reaches 10 N.m.

In the case that the depth of the hollow structure of the lower connecting piece 403 is shallow, compared with the case that a screw (with the size of M5 × 28.5mm and the weight of 5.0g) specially used for FDS (manufactured by Arnold company, germany) is adopted, the mass of a single connecting point is reduced by 3/5, and the problem that the small hollow structure section is difficult to connect due to the long length of the flow drilling screw is solved.

Example 3

As shown in fig. 5, the to-be-connected member 4 employed in the present embodiment includes: upper layer connectors 401 and lower layer connectors 403; the upper layer connecting piece 401 is DP590 high-strength steel with the thickness of 2.0mm and is provided with a prefabricated hole 5; the lower connecting member 403 is a6061-T6 aluminum plate with a thickness of 3.5 mm.

Compared with the embodiment 1, the height of the rivet 1 of the embodiment is 9.0mm, the inner diameter is 3.2mm, and the outer diameter is 6.0 mm; the height of the rivet body 102 is 7.0mm, and the depth of the lower section hollow structure is 4.2 mm; the height of the threaded portion 107 is 3.0 mm; the height of the tapping part 108 is 1.5 mm; the height of the flow drilling section 109 is 2.5 mm.

Compared with embodiment 1, the rivet body 102 of this embodiment has a triangular thread on the lower inner cavity wall, as shown in fig. 2 c.

Compared with the embodiment 1, in the step 1 of the embodiment, the rivet 1, the driving head 2, the blank holder 3 and the prefabricated hole 5 are coaxially arranged, and the driving head 2 drives the rivet 1 to feed so that the taper angle 110 of the rivet 1 penetrates through the prefabricated hole 5 of the upper layer connecting piece 401 and contacts with the upper surface of the lower layer connecting plate 403; in the step 2, the driving head 2 rotates at the rotating speed of 3600rpm and drives the rivet 1 to feed for 2.5mm at the feeding speed of 1 mm/s; in step 3, the driving head 2 drives the rivet 1 to feed for 4.0mm at the rotating speed of 2500 rpm; in step 4, the driving head 2 drives the rivet 1 at a rotation speed of 200rpm until the torque reaches 8 N.m.

The problem that high-strength steel plates are connected with light alloy is solved through the prefabricated holes 5 in the embodiment. Compared with the flow drilling screw process, the rivet 1 adopted by the embodiment is in a semi-hollow design, and the rivet body 102 becomes thicker, so that larger riveting force is transmitted, and higher thread load is provided.

In conclusion, the tip of the rivet does not pierce the lower-layer plate, and compared with the existing unilateral connection process such as a loose core riveting technology and a flowing drilling and riveting technology, the joint sealing performance and the corrosion resistance are greatly improved. Compared with the flowing drilling and riveting process, on one hand, the rivet is of a semi-hollow structure, the design enables the rivet body to be thickened so as to transmit larger torque, the thread load is obviously improved, meanwhile, the rivet quality can be reduced by 3/5, and the process can meet the requirement of light-weight production; on the other hand, the joint obtained by the device realizes the solid-phase connection between the rivet and the workpiece besides the threaded connection, and the bearing capacity of the joint is improved by the threaded-solid-phase composite connection.

The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.