CN115229018A - A kind of forming method of non-standard nut - Google Patents

Abstract

The invention discloses a method for forming a non-standard nut, which comprises the steps of: fixing a bolt on a first connected part, and the connecting thread of the bolt is located on the side close to the second connected part; pre-tightening in a theoretical axial direction The bolt is stretched by force; the geometric parameters of the axial section of the bolt at the connecting thread are obtained; the geometric parameters of the thread of the non-standard nut are determined according to the geometric parameters of the axial section of the connecting thread; out the non-standard nut. The application of non-standard nuts in thread tightening improves the adverse effect of the poor uniformity of stress distribution of metric threaded connections on their connection performance, and solves the problem of the easy generation of connection pairs due to the concentration of occlusal force between existing metric threaded connections. The phenomenon of failure improves the strength and fatigue resistance of the connection pair, the non-standard nut has better strength and mechanical reliability, and the connection strength of the bolt pair is improved.

Description

A kind of forming method of non-standard nut

technical field

The invention relates to the technical field of non-standard fasteners, in particular to a method for forming a non-standard nut.

Background technique

Nut and bolt connection is one of the most commonly used fastening methods. When a normal nut and bolt are used to fix a mechanical part, the thread engagement force tends to concentrate on the 1st to 3rd thread area of the thread near the mating surface under the action of the pre-tightening force. The resulting high stress amplitude causes the fasteners to easily break and fail at this position during the operation of the machine, or cause the fasteners to lose too much preload under long-term service conditions, and the connected parts may slip. Migration fails. The mechanical properties of fasteners are not only related to product reliability, but also to production costs and maintenance costs. In order to solve the above-mentioned related technical problems, it is necessary to develop a non-standard nut.

In summary, how to effectively solve the problem that the connection pair is prone to failure due to the concentration of the occlusal force between the existing metric threaded connections is an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a non-standard nut forming method, the non-standard nut forming method solves the problem that the connection pair is easy to fail due to the concentration of the occlusal force between the existing metric threaded connections, and improves the connection pair. fatigue resistance.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

A method for forming a non-standard nut, comprising the steps of:

Fix the bolt on the first connected part, and the connecting thread of the bolt is located on the side close to the second connected part;

stretching the bolt with theoretical axial preload;

Obtain the geometric parameters of the axial section of the bolt at the connection thread;

Design the thread geometry parameters of the non-standard nut according to the axial section geometry parameters of the connecting thread;

According to the thread geometry parameters, the non-standard nut is processed.

Optionally, in determining the thread geometry parameters of the non-standard nut according to the axial section geometry parameters of the connecting thread, the axial section geometry parameters are the same as the thread geometry parameters.

Optionally, after processing the non-standard nut, the process of connecting the non-standard nut to the bolt includes:

Screw the non-standard nut into the bolt through the thread;

The bolt is stretched with an actual axial preload, and the actual axial preload is equal to the theoretical axial preload;

Keeping the actual pre-tightening force, tighten the non-standard nut to fit the second connected piece.

Optionally, the bolt is a single-ended bolt with a bolt head or a stud bolt with a tightening nut connected at one end.

Optionally, fixing the bolt on the first connected member includes:

screw the bolt head of the bolt into the thread of the first connected part, or fasten the nut to fit the end face of the first connected part;

The bolt head or the end face of the fastening nut is welded on the first connected part.

Optionally, before screwing the non-standard nut onto the bolt through a thread, the method further includes: connecting a washer to the bolt.

The method for forming a non-standard nut provided by the present invention includes the steps of: fixing a bolt on the first connected part, and the connecting thread of the bolt is located on the side close to the second connected part; stretching with a theoretical axial pre-tightening force Bolt; obtain the geometrical parameters of the axial section of the bolt at the connecting thread; determine the geometrical parameters of the thread of the non-standard nut according to the geometrical parameters of the axial section of the connecting thread; process the non-standard nut according to the geometrical parameters of the thread.

By applying the technical solution provided by the embodiment of the present invention, the non-standard nut is applied in the thread tightening, which improves the adverse effect of the poor uniformity of stress distribution of the metric threaded connection on its connection performance, and solves the problem between the existing metric threaded connection. The phenomenon that the connection pair is prone to failure due to the concentration of the occlusal force of the screw teeth, optimizes the distribution of the load between the threaded connection pairs, obtains a more reasonable stress distribution of the threaded connection, improves the force of the threaded connection, and improves the connection pair. The strength and fatigue resistance provide more reasonable suggestions for the design optimization of threaded fasteners; the non-standard nut has better strength and mechanical reliability, and its maintenance friendliness after mass production can reduce the overall cost; bolt pair connection The strength is improved, the interface size of the connected parts can be optimized, and the design cost can be reduced.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a flow chart of a method for forming a non-standard nut provided by a specific embodiment of the present invention;

Fig. 2 is the schematic diagram of bolt fixing;

Fig. 3 is the schematic diagram of bolt stretching;

Figure 4 is a schematic diagram of a non-standard nut connection;

Figure 5 is a schematic diagram of the tension bolt after the non-standard nut is connected;

Fig. 6 is the schematic diagram of non-standard nut tightening;

FIG. 7 is a schematic structural diagram of a non-standard nut and a bolted connector.

The figures are marked as follows:

Non-standard nut 1, bolt 2, bolt head 3, second connected part 4, first connected part 5, washer 6.

Detailed ways

The core of the present invention is to provide a non-standard nut forming method. The non-standard nut forming method solves the problem that the connection pair is easy to fail due to the concentration of the occlusal force between the existing metric threaded connections, and improves the connection pair. fatigue resistance.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1. FIG. 1 is a flowchart of a method for forming a non-standard nut provided by a specific embodiment of the present invention. The forming method for a non-standard nut includes the following steps:

S110: Fix the bolt 2 on the first connected member 5, and the connecting thread of the bolt 2 is located on the side close to the second connected member 4;

In practical application, the end of the bolt 2 with the connecting thread penetrates through the first connected part 5 , the connecting thread penetrates from the second connected part 4 , and the connecting thread extends out of the second connected part 4 . The end of the bolt 2 away from the connecting thread is fixed on the second connected member 4, and the connecting thread of the bolt 2 has not been deformed at this time, as shown in FIG. 2 .

S120: Pull bolt 2 with theoretical axial preload;

In practical applications, the magnitude of the axial tensile preload required by the bolt 2 to connect the first connected part 5 and the second connected part 4 is determined empirically, that is, the theoretical axial preload is determined, and the The theoretical axial preload force Fz1 of this magnitude stretches the bolt 2 from one side of the connecting thread, and applies a theoretical axial preload force to the bolt 2, as shown in Figure 3.

S130: Obtain the geometric parameters of the axial section of the bolt 2 at the connection thread;

In practical application, the bolt 2 produces tensile deformation under the action of the theoretical axial preload force Fz1, and the geometric characteristics of the connecting thread of the bolt 2 change under the theoretical axial preload force, which is recorded in the theoretical axial preload force. The geometric parameters of the axial section of the bolt 2 under the pre-tightening force, that is, to obtain the geometric parameters of the axial section of the bolt 2 at the connection thread. The geometric parameters of the axial section include but are not limited to the profile, profile angle, thread pitch, rise angle, number of lines, etc.

S140: Determine the thread geometry parameters of the non-standard nut 1 according to the axial section geometry parameters of the connecting thread;

In practical applications, when the nut is fastened to bolt 2 and the connection thread is stretched and deformed, the thread geometry parameters of the nut match the axial section geometry parameters of bolt 2 after stretching, that is, the thread geometry parameters of the nut match those of bolt 2. The geometric parameters of the axial section at the connecting thread are similar or even the same. Therefore, the thread geometry parameters of the non-standard nut 1 can be determined according to the axial section geometry parameters of the connecting thread.

S150: According to the geometric parameters of the thread, the non-standard nut 1 is processed.

In practical applications, after the thread geometry parameters of the non-standard nut 1 are determined, the non-standard nut 1 can be processed. It should be noted that the above example takes triangular thread as an example, but the thread design of the non-standard nut 1 should not be limited to the form of the tooth shape, including but not limited to trapezoid, arc, rectangle and the like. The non-standard nut 1 can be freely designed through the cylindrical parts, especially the bolt 2, under the action of different pre-tightening forces, to improve the stress of the thread and reduce the axial deformation of the thread according to the application conditions.

By applying the technical solution provided by the embodiment of the present invention, the non-standard nut 1 is applied in the thread tightening, which improves the adverse effect of the poor uniformity of stress distribution of the metric threaded connection on its connection performance, and solves the problem between the existing metric threaded connection. The phenomenon that the connection pair is prone to failure due to the concentration of the occlusal force of the screw teeth, optimizes the distribution of the load between the threaded connection pairs, obtains a more reasonable stress distribution of the threaded connection, improves the stress of the threaded connection, and improves the connection pair. The strength and fatigue resistance of threaded fasteners provide more reasonable suggestions for the design optimization of threaded fasteners; the non-standard nut 1 has better strength and mechanical reliability, and its maintenance friendliness after mass production can reduce the overall cost; bolts The connection strength of the two pairs is improved, which can optimize the interface size of the connected parts, thereby reducing design costs.

In one embodiment, in designing the thread geometry parameters of the non-standard nut 1 according to the axial section geometry parameters of the connecting thread, the axial section geometry parameters are the same as the thread geometry parameters, and the connection thread between the non-standard nut 1 and the bolt 2 is completely Matching, the metric thread connection will not produce the concentration of the occlusal force of the screw teeth, and the connection pair is not easy to fail.

On the basis of the above specific embodiments, after processing the non-standard nut 1, the process of connecting the non-standard nut 1 to the bolt 2 may include:

Screw the non-standard nut 1 into the bolt 2 through the thread;

Stretch bolt 2 with the actual axial preload, and the actual axial preload is equal to the theoretical axial preload;

Keeping the actual pre-tightening force, tighten the non-standard nut 1 to fit the second connected piece 4 .

For ease of understanding, the above steps are combined for description below.

In practical application, the non-standard nut 1 is screwed into the cylindrical bolt 2 through the thread before the tensile force is applied, as shown in FIG. 4 .

When the bolt 2 is stretched again under the same working conditions as S120, the actual axial preload force Fz2 is the same or similar to the theoretical axial preload force Fz1 in S120, and the error does not exceed ±%2, as shown in Figure 5.

Maintain the actual axial preload force Fz2 in S120 and tighten the non-standard nut 1 to fit the second connected member 4, the thread of which is basically compatible with the changed geometry of the bolt 2 thread, as shown in FIG. 6 .

As shown in FIG. 7 , FIG. 7 shows the non-standard threaded connection in the installed state, which is completely penetrated by the bolt 2 , and the non-standard nut 1 and the bolt 2 are arranged on the surface of the second connected member 4 . On the surface of the first connected member 5, the bolt 2 and the bolt head 3 are arranged. The non-standard nut 1 and the bolt head 3 compress the bolt 2 from both sides of the second connected part 4 and the first connected part 5 , and fix the second connected part 4 and the first connected part 5 .

The non-standard nut 1 solves the phenomenon that the connection pair is prone to failure due to the concentration of the occlusal force between the existing metric threaded connections, optimizes the distribution of the load between the threaded connection pairs, and obtains a more reasonable stress distribution for the threaded connection. The stress of the threaded connection is improved, and the strength and fatigue resistance of the connection pair are improved.

In an embodiment, the above example takes the tensile method as an example, but the application of the non-standard nut 1 should not be limited to the installation form. The bolt 2 can be a single-head bolt 2 with a bolt head 3, or can be connected at one end. The stud bolt 2 with the fastening nut should not limit the fastening form of the other end of the fastener of the bolt 2, including but not limited to the bolt head 3 and the fastened threaded connection, which are widely used.

On the basis of the above embodiment, the bolt 2 is fixed on the first connected member 5, including:

Screw the bolt head 3 of the bolt 2 into the thread of the first connected part 5, or fasten the nut to fit the end face of the first connected part 5;

The end face of the bolt head 3 or the fastening nut is welded to the first connected member 5 .

In practical applications, the bolt 2 and the first connected member 5 can be connected by thread, which is detachable and convenient for connection; it can also be connected by welding, riveting, etc., the connection is firm and reliable, there are many connection forms, and the connection is convenient.

On the basis of the above specific embodiments, before screwing the non-standard nut 1 into the bolt 2 through the thread, it also includes: connecting the gasket 6 to the bolt 2, the gasket 6 can increase the contact area and reduce the pressure, Protect non-standard nuts 1 and bolts 2. Of course, the connection through the gasket 6 is only a preferred embodiment, not the only one. The gasket 6 is not necessarily required, and the gasket 6 may not be directly connected.

The non-standard nut 1 should not limit the attachment of the fastener, such as the gasket 6, nor the structural form and size of the connecting piece and the connected piece, including but not limited to hexagonal flange nuts.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other.

The molding method of the non-standard nut provided by the present invention has been described in detail above. The principles and implementations of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A molding method of a non-standard nut is characterized by comprising the following steps:

fixing a bolt on the first connected piece, wherein the connecting thread of the bolt is positioned on one side close to the second connected piece;

stretching the bolt with a theoretical axial pretension;

acquiring the axial section geometric parameters of the bolt at the connecting thread;

determining the thread geometric parameters of the non-standard nut according to the axial section geometric parameters of the connecting thread;

and processing the non-standard nut according to the geometrical parameters of the thread.

2. The method of claim 1, wherein in designing the thread geometry of the non-standard nut based on the axial cross-sectional geometry of the connecting thread, the axial cross-sectional geometry is the same as the thread geometry.

3. The method for forming the non-standard nut according to claim 1 or 2, wherein the step of attaching the non-standard nut to the bolt after the non-standard nut is machined comprises:

screwing the non-standard nut into the bolt through threads;

stretching the bolt by using an actual axial pretightening force, wherein the actual axial pretightening force is equal to the theoretical axial pretightening force;

and keeping the actual pretightening force, and screwing the non-standard nut to be attached to the second connected piece.

4. The method for forming a non-standard nut according to claim 3, wherein the bolt is a single head bolt having a bolt head or a double head bolt having a fastening nut attached to one end thereof.

5. The method for forming a non-standard nut according to claim 4, wherein the step of fixing the bolt to the first member to be connected includes:

screwing the bolt head of the bolt into the thread of the first connected piece, or attaching a fastening nut to the end face of the first connected piece;

and welding the end face of the bolt head or the fastening nut to the first connected piece.

6. The method for forming a non-standard nut according to claim 3, wherein before screwing the non-standard nut onto the bolt, the method further comprises: attaching a washer to the bolt.

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