阅读说明：本技术 一种高锁紧防裂纹的芯轴及其收口方法 (High-locking anti-crack mandrel and closing method thereof ) 是由 郭双双 魏亮亮 刘玉生 齐增星 单垄垄 于 2021-08-02 设计创作，主要内容包括：本发明创造提供了一种高锁紧防裂纹的芯轴及其收口方法,包括以下步骤：S1：在螺母内穿入芯轴,芯轴穿入位置应包含住螺母上要收口的位置；S2：使用收口模具对螺母进行收口,螺母收口部位的内螺纹受到收口模和芯轴的挤压,其内螺纹的螺纹牙的形态产生受控变化。本发明创造所述的一种高锁紧防裂纹的芯轴及其收口方法,能够在常温下进行,可产生较高的锁紧力矩,可防止出现裂纹。(The invention provides a high-locking anti-crack mandrel and a closing method thereof, which comprise the following steps: s1: a core shaft penetrates into the nut, and the penetrating position of the core shaft comprises a position to be closed on the nut; s2: and closing the nut by using a closing-up die, wherein the internal thread at the closing-up part of the nut is extruded by a closing-up die and a mandrel, and the shape of the thread teeth of the internal thread is subjected to controlled change. The high-locking anti-crack mandrel and the closing method thereof can be carried out at normal temperature, can generate higher locking torque and can prevent cracks.)

1. The utility model provides a dabber of crackle is prevented to high locking which characterized in that: the outer wall of the mandrel is provided with an external thread, the thread angle, the pitch diameter, the small diameter and the pitch of the external thread are equal to those of the bolt external thread corresponding to the nut internal thread, and the major diameter of the external thread is smaller than that of the bolt external thread corresponding to the nut internal thread.

2. The high lock crack resistant mandrel of claim 1 wherein: the major diameter range of the mandrel external thread is as follows: d2- (d1-d3)/4 is not less than d and not more than d2+ (d1-d 3)/4;

the major diameter of the bolt external thread corresponding to the nut internal thread is d 1;

the pitch diameter of the bolt external thread corresponding to the nut internal thread is d 2;

the minor diameter of the external thread of the bolt corresponding to the internal thread of the nut is d 3;

the major diameter of the mandrel external thread is d.

3. The high lock crack resistant mandrel of claim 1 wherein: the large diameter position of the external thread of the mandrel is a plane or a curved surface.

4. The high lock crack resistant mandrel of claim 1 wherein: the shaft core is of a fixed solid structure.

5. The high lock crack resistant mandrel of claim 1 wherein: the axle core is the components of a whole that can function independently structure that can expand and contract, the axle core includes the fixed axle, screw thread dabber inner core, a plurality of screw thread dabber multilobe shell, screw thread dabber inner core sets up in the fixed axle, a plurality of screw thread dabber multilobe shell sets up the one end at the fixed axle along the circumference, the inside wall setting of a plurality of screw thread dabber multilobe shell is on the circumference in gap, external screw thread on the outer wall of dabber is located the outer wall of screw thread dabber multilobe shell, be equipped with the through-hole coaxial with the gap on the fixed axle, the diameter of through-hole is the diameter of screw thread dabber inner core at least, the diameter in gap is less than the diameter of through-hole.

6. The high lock crack resistant mandrel of claim 4 wherein: one end of the threaded mandrel inner core is conical, and a reducing transition section is arranged at the joint of the through hole of the fixing shaft and the gap.

7. The high lock crack resistant mandrel of claim 5, wherein: the fixed shaft is made of flexible materials or elastic materials, and the threaded mandrel multi-petal shell is made of metal materials.

8. A closing method of a high-locking anti-crack mandrel, which adopts the mandrel for closing a nut as claimed in any one of claims 1 to 6, and is characterized in that: the method comprises the following steps:

s1: a core shaft penetrates into the nut, and the penetrating position of the core shaft comprises a position to be closed on the nut;

s2: and closing the nut by using a closing-up die, wherein the internal thread at the closing-up part of the nut is extruded by a closing-up die and a mandrel, and the shape of the thread teeth of the internal thread is subjected to controlled change.

9. A closing method of a high locking crack prevention mandrel as claimed in claim 8, wherein: the axle core is fixed entity structure, and the axle core directly closes to penetrate and unload the nut soon through the screw thread in S1 and with the dabber is unloaded, but the axle core is the components of a whole that can expand and contract components of a whole that can function independently structure, directly closes to penetrate and unload through the screw thread in S1 and with the dabber is unloaded, in the gap of inserting the multi-petal shell of screw mandrel with the screw mandrel inner core in S1, extract the back in unloading the dabber with the screw mandrel inner core from the multi-petal shell of screw mandrel, the pitch diameter and the path of the external screw thread of the multi-petal shell of screw mandrel can reduce.

10. A closing method of a high locking crack prevention mandrel as claimed in claim 9, wherein: the number of the petals of the mandrel multi-petal shell is equal to the number of the closing die heads in the step S2, and the closing die in the step S2 is positioned in the middle of the threaded mandrel multi-petal shell, cannot be positioned at the edge of the threaded mandrel multi-petal shell, and cannot be positioned in the gap between the threaded mandrel multi-petal shells.

Technical Field

The invention belongs to the technical field of fastener manufacturing, and particularly relates to a high-locking anti-crack mandrel and a closing method thereof.

Background

The all-metal self-locking nut is a nut with a self-locking effect, and has a large application range and application amount. The locking structures of nuts are of various types, and can be divided into mechanically fixed locking structures and friction force increasing locking structures according to the working principle, wherein the friction force increasing locking structures can be divided into effective torque type locking structures and free rotation type locking structures according to the locking principle. The effective moment refers to the measured rotation moment of the threaded connection pair when the nut is smoothly rotated under the condition of not bearing axial load. The torque has a locking function of resisting relative rotation between the threaded connection pairs. The locking behavior of such nuts is not completely dependent on the pretensioning force of the screw connection. Such as: self-locking nut. The effective torque type self-locking nut can be divided into an all-metal self-locking nut and a non-metal insert self-locking nut. The working principle of the all-metal self-locking nut is as follows: the locking structure of the self-locking nut is subjected to compression deformation, and when the threads of the locking part of the self-locking nut are screwed with the bolt, the self-locking nut is extruded by the threads of the bolt to restore the original shape, so that the nut generates elastic deformation and elastic deformation force, and friction torque for preventing rotation, namely the locking torque of the self-locking nut, is generated due to the interference effect of the elastic deformation force on the threads of the bolt.

Generally, a greater amount of crimping is required to produce a higher tightening torque, but as the amount of crimping increases, the risk of cracking in the internal thread increases. And the internal thread is ensured to have no crack while ensuring enough locking torque, and the difficulty is very high. A common improvement is to heat the pinch-off and increase the plasticity by heating the nut, thus reducing the risk of cracks. However, heating brings a series of problems of heating mode, heating transfer, temperature control, nut material heat influence, nut surface heat influence, shrinking die thermal expansion and cold contraction size change, shrinking die thermal working life, thermal protection and the like.

Disclosure of Invention

In view of the above, the invention aims to provide a high-locking anti-crack mandrel and a closing method thereof.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

the utility model provides a dabber for nut binding off, is equipped with the external screw thread on the outer wall of dabber, the profile angle, pitch diameter, path and the pitch of external screw thread are equal to the profile angle, pitch diameter, path and the pitch of the bolt external screw thread that the nut internal thread corresponds, the major diameter of external screw thread is less than the major diameter of the bolt external screw thread that the nut internal thread corresponds.

The major diameter range of the mandrel external thread is as follows: d2- (d1-d3)/4 is not less than d and not more than d2+ (d1-d 3)/4;

the major diameter of the bolt external thread corresponding to the nut internal thread is d 1;

the pitch diameter of the bolt external thread corresponding to the nut internal thread is d 2;

the minor diameter of the external thread of the bolt corresponding to the internal thread of the nut is d 3;

the major diameter of the mandrel external thread is d.

Furthermore, the large diameter position of the internal thread of the mandrel is a plane or a curved surface.

Further, the shaft core is of a fixed solid structure.

Further, the axle core is the components of a whole that can expand and contract structure, and the axle core includes the fixed axle, screw thread dabber inner core, a plurality of screw thread dabber multi-petal shell, and screw thread dabber inner core sets up in the fixed axle, and a plurality of screw thread dabber multi-petal shell sets up the one end at the fixed axle along the circumference, and the inside wall setting of a plurality of screw thread dabber multi-petal shell is on the circumference in gap, and the external screw thread on the outer wall of dabber is located the outer wall of screw thread dabber multi-petal shell, is equipped with the through-hole coaxial with the gap on the fixed axle, and the diameter of through-hole is the diameter of screw thread dabber inner core at least, and the diameter in gap is less than the diameter of through-hole.

Furthermore, one end of the threaded mandrel inner core is conical, and a reducing transition section is arranged at the joint of the through hole of the fixing shaft and the gap.

Furthermore, the shaft core is made of flexible materials or elastic materials, such as beryllium copper, nickel-titanium alloy, spring steel, rubber and latex, and the multi-petal shell of the threaded shaft core is made of metal materials.

A high-locking anti-crack mandrel and a closing method thereof comprise the following steps:

s1: a core shaft penetrates into the nut, and the penetrating position of the core shaft comprises a position to be closed on the nut;

s2: and closing the nut by using a closing-up die, wherein the internal thread at the closing-up part of the nut is extruded by a closing-up die and a mandrel, and the shape of the thread teeth of the internal thread is subjected to controlled change.

Furthermore, the shaft core is of a fixed solid structure, and the shaft core is directly screwed into and out of the nut through threads in the process of S1 and the process of unloading the shaft core.

Furthermore, the shaft core is of an expandable and contractible split structure, the shaft core is directly screwed and penetrated through threads in S1 and the process of unloading the shaft core, the inner core of the threaded shaft core is inserted into a gap of the multi-petal shell of the threaded shaft core in S1, and after the inner core of the threaded shaft core is pulled out of the multi-petal shell of the threaded shaft core, the middle diameter and the small diameter of the external thread of the multi-petal shell of the threaded shaft core can be reduced.

Furthermore, the number of the petals of the mandrel multi-petal shell is equal to the number of the closing dies in the step S2, and the closing position of the closing die in the step S2 should be at the middle position of the threaded mandrel multi-petal shell, cannot be located at the edge position of the closing die on the threaded mandrel multi-petal shell, and cannot be located at the gap between the threaded mandrel multi-petal shells.

Compared with the prior art, the high-locking anti-crack mandrel and the closing method thereof have the following beneficial effects:

according to the high-locking anti-crack mandrel and the closing method thereof, the relatively large locking torque can be generated at normal temperature with relatively small closing deformation, the defects such as cracks and the like are avoided, the expandable and contractible threads with the split structure are used, and when the threads are screwed in and out of the nut, more convenience can be obtained through expansion and contraction of the middle diameter and the small diameter of the multi-lobe shell of the threaded mandrel, and the threaded mandrel is convenient to disassemble.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the invention without limitation. In the drawings:

FIG. 1 is a schematic view of a self-locking nut that has not yet been necked-in deformed;

FIG. 2 is a schematic view of the closing-up effect obtained by closing up the nut shown in FIG. 1 in a conventional manner;

FIG. 3 is a photomicrograph of the thread in the necked-in area of FIG. 2 showing cracking;

FIG. 4 is a schematic view of a mandrel for holding a solid structure in accordance with the present invention;

FIG. 5 is a schematic view of the threads after the mandrel of the present invention has been threaded into a nut;

FIG. 6 is a schematic view of the nut shown in FIG. 1 after being closed up by the method of the present invention;

FIG. 7 is a photomicrograph of the internal threads of the necked-in portion of FIG. 6;

FIG. 8 is a schematic view of the core of the split expandable and contractible mandrel of the present invention in a pulled-out state;

fig. 9 is a schematic view of the mandrel core in a plugged state of the expandable split structure of the invention.

Drawings

1-position one; 2-position two; 3-voids; 4-position three; 5-a threaded mandrel multi-lobed housing; 6-gap.

Detailed Description

It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings, which are merely for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "connected" are to be construed broadly, e.g. as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

The invention will be described in detail with reference to the following embodiments with reference to the attached drawings.

A high-locking anti-crack closing method comprises the following three steps: step one, a core shaft penetrates into a nut, and the penetrating position of the core shaft comprises a position to be closed on the nut; secondly, closing the nut by using a closing-up die, wherein the internal thread at the closing-up part of the nut is extruded by a closing-up die and a core shaft, and the form of the thread tooth is controlled to change; and step three, unloading the mandrel. Wherein step three may optionally not be performed.

The nut refers to a self-locking nut which needs to be subjected to closing deformation but is not subjected to closing deformation, and the nut comprises an internal thread structure.

The mandrel is a mandrel with a special external thread, and the mandrel can be screwed in and out by freely screwing the special external thread with the nut which is not closed up. The tooth form of the special external thread is obtained by modifying the external thread of the bolt corresponding to the internal thread of the nut. The thread form angle, the pitch diameter, the small diameter and the pitch of the special external thread are equal to those of the external thread of the bolt corresponding to the internal thread of the nut. The major diameter of the special external thread is smaller than that of the bolt external thread corresponding to the nut internal thread and is approximately equal to the pitch diameter of the bolt external thread corresponding to the nut internal thread, and the major diameter of the special external thread can be flat or warped to a certain extent. The tooth form of the special external thread is designed in such a way that after the mandrel is screwed into the nut, a space with a specific volume in a specific form is formed between the large diameter of the external thread of the mandrel and the large diameter of the internal thread of the nut. The space is used for enabling the extruded internal thread to deform and flow into the specific space in the second step, so that the shape of the internal thread ridge is changed specifically. When the form of the inner thread tooth at the closing position of the nut generates the specific change, the thread pair between the nut and the bolt is changed from integral clearance fit into local interference fit, and by the method, enough locking torque can be generated when the closing amount is small. In the second step, after the nut is extruded, the deformation space of the nut is controlled, and cracks are not easy to generate.

The structure of the thread part of the mandrel is divided into two types. The first is to fix the thread of the solid structure, i.e. to make a special external thread on the solid cylinder. The threaded mandrel of the first construction is threaded directly into and out of the nut in the first closing step and the third closing step. The second kind is the screw thread of the components of a whole that can function independently structure that can expand and contract, the components of a whole that can function independently structure screw thread mainly comprises two parts structure, be screw mandrel multi-disc shell and screw mandrel inner core respectively, with the screw mandrel inner core fill in the screw mandrel multi-disc shell, can make the screw mandrel multi-disc shell inflation, screw pitch diameter and path after the inflation equals pitch diameter and the path of the external screw thread that the nut internal thread corresponds, extract back in the screw mandrel multi-disc shell with the screw mandrel inner core, the pitch diameter and the path of screw mandrel multi-disc shell can reduce. In the first closing step and the third step of the threaded mandrel with the second structure, when the threads are screwed in and penetrate into and out of the nut, more convenience can be obtained through expansion and contraction of the middle diameter and the small diameter of the multi-section shell of the threaded mandrel. And the number of the petals of the multi-petal shell of the threaded mandrel is equal to the number of the closing-in pressure heads in the second step, and when the closing-in is performed in the second step, the closing-in pressure heads are pressed at the middle position of the entity of the multi-petal shell of the threaded mandrel, but cannot be pressed at the edge position of the shell and cannot be pressed at the gap between the shells.

Example one

Fig. 4 is a schematic view of a mandrel for holding a solid structure according to the present invention. The mandrel is provided with a special external thread, and the tooth form of the special external thread is obtained by modifying the external thread of the bolt corresponding to the internal thread of the nut. The thread form angle, the pitch diameter, the small diameter and the pitch of the special external thread are equal to those of the external thread of the bolt corresponding to the internal thread of the nut. The major diameter of the special external thread is smaller than that of the bolt external thread corresponding to the nut internal thread and is approximately equal to the pitch diameter of the bolt external thread corresponding to the nut internal thread. The difference between the external thread of the spindle and the external thread of the bolt corresponding to the nut in the present invention is shown by the dotted line in fig. 4.

The nut shown in fig. 1 is necked in using three steps of the invention: step one, threading the core shaft shown in figure 4 into the nut shown in figure 5 through screwing, wherein the threading position of the core shaft already comprises the position to be closed on the nut, and a gap 3 with a specific volume in a specific form is formed between the major diameter of the external thread of the core shaft and the major diameter of the internal thread of the nut; step two, using a closing-in die to close the nut, wherein the closing-in amount of the invention adopted in the embodiment is only one third of the closing-in amount of the traditional method, and when closing in, the internal thread at the closing-in position of the nut is extruded by a closing-in die and a core shaft, so that the internal thread metal entity deforms and flows into the gap 3, as shown in the position three 4 in fig. 6; and thirdly, the core shaft is rotationally unloaded, and the self-locking nut which has the locking torque required by the product standard and has no cracks is obtained. The microscopic metallography of the internal thread at the closed part is shown in figure 7.

Example two

Fig. 8 is a schematic view showing a state where the mandrel core of the expandable and contractible split structure of the present invention is pulled out, fig. 9 is a schematic view showing a state where the mandrel core of the expandable and contractible split structure of the present invention is plugged in, and the number of the lobes of the multi-lobed shell of the threaded mandrel in this embodiment is three. The method for closing the nut by using the mandrel comprises the following three steps: step one, a core shaft shown in a figure 8 is penetrated into a nut, the penetrating position of the core shaft comprises a position to be closed on the nut, and then an inner core is inserted into the core shaft to enable the core shaft to be in a state shown in a figure 9, or the core shaft is screwed into the nut after being changed into the state shown in the figure 9; secondly, closing the nut by using a closing-up die, wherein the closing-up position corresponds to the middle position of the multi-petal shell 5 of the threaded mandrel of the mandrel, but cannot correspond to the edge position of the multi-petal shell 5 of the threaded mandrel and cannot correspond to the gap 6, the internal thread at the closing-up position of the nut is extruded by the closing-up die and the mandrel, and the shape of the thread teeth of the nut is subjected to controlled change; and step three, pulling out the inner core from the mandrel to enable the mandrel to be in the state shown in the figure 8, and then unloading the mandrel from the nut.

Comparative example 1

Fig. 1 is a self-locking nut which is not yet subjected to necking deformation, the necking effect obtained after three-point necking is performed on the self-locking nut in a traditional mode is shown in fig. 2, a first position 1 in the drawing is an external surface indentation left for necking, internal threads at a second corresponding position 2 are also deformed, and in order to achieve the locking torque required by product standards, the necking deformation amount is required to be large enough.

TABLE 1 closing amount and tightening torque of example 1, example 2, and comparative example 1

	Example 1	Example 2	Comparative example 1
				Amount of closing up	0.1mm	0.1mm	0.3mm
Locking torque	3.2Nm	3.1Nm	3Nm

As can be seen from table 1, the closing amount of examples 1 and 2 is 0.1, the closing amount of comparative example 1 is 0.3, the tightening torque of example 1 is 3.2Nm, the tightening torque of example 2 is 3.1Nm, and the tightening torque of comparative example 1 is 3Nm, so that a large tightening torque can be generated at a small closing deformation amount at normal temperature, the female screw in comparative example 2 is deformed as can be seen from the position two 2 in fig. 2, and the type deformation amount of the female screw in example 1 is small as can be seen from fig. 6.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the invention, so that any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present invention, should be included in the scope of the present invention.