Positive and negative tooth combined threaded connection structure

Abstract

The invention discloses a positive and negative tooth combined threaded connection structure which comprises a connecting piece, a connected piece, a connecting nut and a bolt. The connecting piece, the connected piece and the connecting nut are all provided with mounting holes for bolts to penetrate through. A nut end is arranged at one end, far away from the connecting piece, of the connected piece, and an internal thread is arranged at the nut end; the connecting nut comprises a nut main body and an outer nut extending outwards; the outer nut is provided with an internal thread and an external thread, the nut body is provided with an internal thread, the internal thread of the nut body is connected with the internal thread of the outer nut to form a complete internal thread of the connecting nut, and the external thread of the outer nut and the internal thread of the nut end form a first thread pair; the internal thread of the connecting nut and the bolt form a second thread pair, and the looseness of the first thread pair is larger than that of the second thread pair.

Description

Technical Field

[0001] The present invention belongs to the technical field of bolt - nut connection, and particularly relates to a combined left - hand and right - hand thread connection. Background Art

[0002] Vibration can cause bolts to loosen or wear. Over time, this can lead to the failure of the bolt pre - tightening force, and further cause relative displacement between the connecting parts, between the connecting parts and the bolt - nut, thus losing the connection function. Summary of the Invention

[0003] Object of the Invention: To solve the deficiencies in the background art, the present invention proposes a combined left - hand and right - hand thread connection structure, which can be used in all fields that require bolt - nut combination connection.

[0004] Technical Solution: A combined left - hand and right - hand thread connection structure includes: a connecting part, a connected part, a connecting nut and a bolt; the connecting part, the connected part and the connecting nut are all provided with mounting holes for the bolt to pass through; at one end of the connected part away from the connecting part, there is a nut end, and the nut end is provided with an internal thread; the connecting nut includes a nut body and an external nut extending outwards; the external nut is provided with an internal thread and an external thread, the nut body is provided with an internal thread, the internal thread of the nut body is continuous with the internal thread of the external nut to form a complete internal thread of the connecting nut, and the external thread of the external nut and the internal thread of the nut end form a first thread pair; the internal thread of the connecting nut and the bolt form a second thread pair, and the looseness of the first thread pair is greater than that of the second thread pair.

[0005] Further, it also includes a counter - nut; the counter - nut is fixedly connected to the top of the bolt.

[0006] Further, the helix direction of the internal thread of the nut end is opposite to that of the internal thread of the connecting nut.

[0007] Further, the pitch of the internal thread of the nut end is greater than the pitch of the internal thread of the connecting nut.

[0008] Further, the helix direction of the external thread of the external nut is opposite to that of the internal thread of the connecting nut.

[0009] Further, the diameter of the mounting hole is the same as the diameter of the bolt.

[0010] Advantageous Effects: Compared with the prior art, the present invention has the following advantages:

[0011] (1) While the connected parts of the present invention are effectively connected by bolts and nuts, through the connection between the nut end of the connected part and the outer nut of the connecting nut, the connection rigidity between the connected part and the bolts and nuts is greatly increased, eliminating the relative displacement between the connecting parts and between the connecting parts and the bolts and nuts caused by the clearance resulting from the bolt hole being larger than the bolt diameter;

[0012] (2) The present invention can greatly reduce problems such as bolt loosening and wear of the end faces of the connecting parts caused by vibration, greatly improving the stability of the connection structure; at the same time, the installation of the present invention is more convenient and labor-saving, and the double-nut method can better ensure bolt anti-loosening;

[0013] (3) An internal thread is added to the nut end of the connected part of the present invention. After installation, the connecting nut and the nut end of the connected part are relatively fixed to form a connecting part, achieving an overall effect. If relative lateral displacement occurs, not only does the end face need to overcome the frictional force, but it also needs to climb along the tooth angle, increasing the difficulty of displacement. This climbing will also greatly increase the bolt pre-tightening force; therefore, the present invention makes it more difficult and with a smaller amplitude for relative lateral displacement to occur between the two connecting parts through the rigid transmission of the bolt, protecting the connected part and the objects inside the end face of the connected part;

[0014] (4) The pitch of the internal thread at the nut end of the connected part designed in the present invention is greater than the tooth pitch of the internal thread of the connecting nut, resulting in inconsistent lifting angles of the two threads when loosening occurs, locking the nut; and physically ensuring that the looseness of the thread pair formed by the two is greater than that of the thread pair formed by the connecting nut and the bolt, ensuring that the looseness of this thread pair is greater after tightening. In the double-nut tightening, its rotation direction is opposite to that of the counter nut, ensuring greater frictional force between the two nuts and playing an overall anti-loosening role;

[0015] (5) The connecting nut designed in the present invention has internal and external reverse threads, and the pitch of the internal thread at the nut end of the connected part is greater than the tooth pitch of the internal thread of the connecting nut. Once the two thread pairs enter the engaged state and rotate, the nut will move in the opposite direction to the bolt. Then, only by rotating the bolt can the bolt be tightened unidirectionally without the need to additionally fix the nut, making the installation more convenient and reliable;

[0016] (6) While the bolts and nuts are effectively connected in the present invention, the connection rigidity between the connected part and the bolts and nuts is greatly increased, eliminating the relative displacement between the connecting parts and between the connecting parts and the bolts and nuts caused by the clearance generated after the bolt hole is larger than the bolt diameter, thereby reducing or avoiding bolt loosening and wear of the end faces of the connecting parts caused by vibration, and greatly improving the structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a combined positive and reverse thread connection structure proposed by the present invention;

[0018] Figure 2DN15 flange structure diagram made by using a positive and negative thread combination thread connection structure proposed by the present invention. Detailed implementation manners

[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the specific implementation manners and with reference to the accompanying drawings. It should be understood that these descriptions are exemplary and are not intended to limit the scope of the present invention.

[0020] As Figure 1 shown, this embodiment proposes a positive and negative thread combination thread connection structure, which mainly includes: a connecting member 1, a connected member 2, a connecting nut 3, an opposing nut 4 and a bolt 5. The connected member 2 is provided with a nut end 21. The connecting nut 3 includes a nut body 31 and an outer nut 32 extending outwards. The internal thread of the outer nut 32 is continuous with the internal thread of the nut body 31 and matches the thread of the bolt 5. The external thread of the outer nut 32 matches the internal thread of the nut end 21 on the connected member 2, that is, the connected member 2 is threadedly connected to the outer nut 32 of the connecting nut 3 through its nut end 21.

[0021] After the bolt 5 passes through the through hole of the connecting member 1, it forms a threaded connection with the internal thread of the connecting nut 3 that has been threadedly connected to the connected member 2. After the bolt 5 passes through the connecting nut 3, it is connected and fixed to the internal thread of the opposing nut 4, thereby completing the connection between the connecting member 1 and the connected member 2. The opposing nut 4 is used to fix the top of the bolt 5 and plays a role in preventing loosening of the double nuts. In this embodiment, through the rigid transmission of the bolt, it is more difficult and with a smaller amplitude for the two connecting members to have a lateral relative displacement.

[0022] Now, the details of the connection structure in this embodiment will be further described. The helix direction of the internal thread of the nut end 21 on the connected member 2 is opposite to the helix direction of the internal thread of the connecting nut 3, and the pitch of the internal thread of the nut end 21 on the connected member 2 is greater than the pitch of the internal thread of the connecting nut 3, making the looseness of its thread pair greater than that of the thread pair formed by the connecting nut 3 and the bolt 5. The helix direction of the external thread of the connecting nut 3 is opposite to the helix direction of its internal thread. According to the pitch size, the external thread diameter is reduced, and the clearance between its threads is increased, that is, the internal thread of the nut end 21 on the connected member 2 is connected to the external thread of the connecting nut 3 and the clearance is increased. Through the clearance, the position requirements for the porous connecting body can be reduced, thereby eliminating the overall machining error, reducing the precision requirements and costs, and replacing precision machining with rough machining.

[0023] In this embodiment, the clearance between the internal thread of the nut end 21 and the external thread of the outer nut 32 can be appropriately adjusted to facilitate the concentricity requirements during the installation of multiple bolts.

[0024] The through hole that cooperates with the bolt 5 in this embodiment is designed according to the mating method of a reamed hole bolt of the same specification, so that the through hole of the bolt connection member is infinitely reduced and approaches the bolt diameter, eliminating the possibility of lateral displacement.

[0025] Figure 2 The figure shows a schematic diagram of applying a positive and negative thread combination thread connection structure proposed in this embodiment to a DN15 flange structure.

Claims

1. A positive and negative thread combination thread connection structure, characterized in that: include: A connecting member (1), a connected member (2), a connecting nut (3) and a bolt (5); The connecting member (1), the connected member (2) and the connecting nut (3) are all provided with mounting holes for the bolts (5) to pass through; A nut end (21) is provided at one end of the connected member (2) away from the connecting member (1), and the nut end (21) is provided with an internal thread; The connecting nut (3) comprises a nut body (31) and an outer nut (32) extending outward; the outer nut (32) is provided with an inner thread and an outer thread, the nut body (31) is provided with an inner thread, the inner thread of the nut body (31) is connected with the inner thread of the outer nut to form a complete inner thread of the connecting nut (3), and the outer thread of the outer nut (32) and the inner thread of the nut end (21) form a first thread pair; the inner thread of the connecting nut (3) and the bolt (5) form a second thread pair, and the looseness of the first thread pair is greater than the looseness of the second thread pair.

2. A positive and negative thread combination thread connection structure according to claim 1, characterized in that: It also includes a top nut (4); the top nut (4) is fixedly connected to the top of the bolt (5).

3. The positive and negative thread combination thread connection structure according to claim 1, characterized in that: The rotation direction of the internal thread of the nut end (21) is opposite to the rotation direction of the internal thread of the connecting nut (3).

4. The positive and negative thread combination thread connection structure according to claim 1, characterized in that: The pitch of the internal thread of the nut end (21) is greater than the pitch of the internal thread of the connecting nut (3).

5. The positive and negative thread combination thread connection structure according to claim 1, characterized in that: The rotation direction of the external thread of the external nut (32) is opposite to the rotation direction of the internal thread of the connecting nut (3).

6. The positive and negative thread combination thread connection structure according to claim 1, characterized in that: The diameter of the mounting hole is consistent with the diameter of the bolt (5).

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