Threaded nail and nail sleeve, and nail sleeve manufacturing method

Abstract

The present invention discloses a threaded pull-out nail and its nail sleeve, and a method for manufacturing the nail sleeve. The method comprises the following steps: sequentially dividing the nail sleeve semi-finished product into a first length segment greater than the length of the insert, a second length segment, and a third length segment greater than the length of the closing portion; heat-treating the first length segment of the nail sleeve semi-finished product at a first heating temperature, and heat-treating the second length segment of the nail sleeve semi-finished product at a second heating temperature; the first heating temperature is higher than the second heating temperature; after heat-treating the first length segment and the second length segment, performing deep cold treatment on the nail sleeve semi-finished product, so that the first length segment constitutes the main deformation segment of the nail sleeve, the second length segment constitutes the transition deformation segment of the nail sleeve, and the third length segment constitutes the supporting segment of the nail sleeve. The present invention enables the nail sleeve to form a three-segment incremental structure of low strength, medium strength, and high strength, so that the length segments of different strengths play their due roles, improve the quality stability of the product, and ensure that the pier head of the riveted installation of the threaded pull-out nail is in a bell tower shape.

Description

Technical Field

[0001] The invention relates to the technical field of fasteners, and in particular to a threaded pull-out nail, a nail sleeve and a nail sleeve manufacturing method. Background Art

[0002] The structures of high-end equipment such as aerospace are generally designed to be compact. The connection and installation space of these compactly designed structural parts is relatively small. Ordinary bolt and nut fasteners cannot meet the installation requirements of these occasions because they need to be installed on both sides. Therefore, in these narrow spaces, single-sided fasteners are generally selected, such as threaded pull-out nails, also known as core-pulling rivets. With the increasing application of composite materials in aircraft and the increasing amount of use, the application of threaded pull-out nails suitable for composite material connection is becoming more and more extensive and the amount of use is increasing. The typical representative of this type of threaded pull-out nail is the large-foot type pull-out nail, which mainly relies on the deformation of the nail sleeve to produce a large foot and cooperate with the nail body to lock the installation interlayer. In order to make the nail sleeve deform smoothly, in the prior art, the nail sleeve will be heat-treated during the manufacturing process of the nail sleeve. The heating methods of heat treatment mainly include electric furnace heating, resistance heating, salt bath heating and vacuum heating. However, the above methods can only heat the nail sleeve as a whole, so the overall organization of the nail sleeve will change, and the product quality stability is poor. Summary of the invention

[0003] The purpose of the present invention is to provide a threaded nail and its nail sleeve, and a nail sleeve manufacturing method, so as to solve the technical problem that the nail sleeve is heat treated during the current manufacturing process of the nail sleeve, causing the overall structure of the nail sleeve to change and the product quality stability is poor.

[0004] The above-mentioned purpose of the present invention can be achieved by adopting the following technical solutions:

[0005] The present invention provides a method for manufacturing a nail sleeve, wherein the first end of the nail sleeve can form a closing portion after the nail sleeve is assembled with a core rod, and the second end of the nail sleeve is provided with a stepped hole for installing an insert, and the length of the insert is less than the length of the stepped hole; the method for manufacturing the nail sleeve comprises the following steps: preparing a nail sleeve blank; machining the stepped hole at one end of the nail sleeve blank to obtain a nail sleeve semi-finished product; dividing the nail sleeve semi-finished product into a first length segment, a second length segment and a third length segment in sequence from one end of the nail sleeve semi-finished product close to the stepped hole to the other end of the nail sleeve semi-finished product; wherein the length of the first length segment is greater than the length of the insert the length of the insert, the second length segment is connected to the first length segment, and the length of the third length segment is greater than the length of the closing portion; the first length segment of the semi-finished nail sleeve is heat treated at a first heating temperature, and the second length segment of the semi-finished nail sleeve is heat treated at a second heating temperature; wherein the first heating temperature is higher than the second heating temperature; after the first length segment and the second length segment are heat treated, the semi-finished nail sleeve is cryogenically treated, so that the first length segment constitutes the main deformation segment of the nail sleeve, the second length segment constitutes the transition deformation segment of the nail sleeve, and the third length segment constitutes the supporting segment of the nail sleeve.

[0006] In an embodiment of the present invention, the length of the first length segment is L1, the length of the insert is l1, and they have the relationship: 0.5mm≤(L1-l1)≤2.0mm; the length of the third length segment is L3, the length of the closing portion is l2, and they have the relationship: 1.5mm≤(L3-l2)≤5.5mm.

[0007] In an embodiment of the present invention, the first heating temperature is 950°C to 1050°C, and the second heating temperature is 850°C to 950°C.

[0008] In an embodiment of the present invention, the heating method for heat treating the first length segment and the second length segment is induction heating.

[0009] In an embodiment of the present invention, the heat treatment of the first length segment includes: sleeveing ​​a first induction heating coil outside the first length segment for induction heating; wherein the length of the first induction heating coil is equal to the length of the first length segment; the heat treatment of the second length segment includes: sleeveing ​​a second induction heating coil outside the second length segment for induction heating; wherein the length of the second induction heating coil is equal to the length of the second length segment.

[0010] In an embodiment of the present invention, the preparation of the nail sleeve blank comprises: using a hard stainless steel pipe to obtain the nail sleeve blank; wherein the tensile strength of the hard stainless steel pipe is 800Mpa to 1050Mpa.

[0011] In an embodiment of the present invention, the cryogenic treatment of the semi-finished nail sleeve comprises: placing the semi-finished nail sleeve in a cold box for cryogenic treatment; wherein the cold box is filled with liquid nitrogen and the temperature in the cold box is -90°C.

[0012] In an embodiment of the present invention, after heat treating the first length segment and the second length segment and before cryogenically treating the semi-finished nail sleeve product, the method further includes: blowing inert gas into the semi-finished nail sleeve product to rapidly cool the semi-finished nail sleeve product.

[0013] In an embodiment of the present invention, before heat treating the first length segment and the second length segment, it also includes: cleaning the surface dirt of the nail sleeve semi-finished product; after deep freezing the nail sleeve semi-finished product, it also includes: performing surface lubrication treatment on the nail sleeve semi-finished product.

[0014] The present invention also provides a nail sleeve, which is made by the above-mentioned nail sleeve manufacturing method; the second end of the nail sleeve is provided with a step hole, and the nail sleeve forms a main deformation section, a transition deformation section and a support section in sequence from the second end to the first end.

[0015] The present invention also provides a threaded pull-out nail, comprising the above-mentioned nail sleeve, the threaded pull-out nail also comprising a core rod, a nail body, an insert and a drive nut, the first end of the core rod is provided with a head boss, the nail sleeve, the nail body and the drive nut are sequentially sleeved on the core rod from the second end of the core rod, the first end of the nail sleeve abuts against the head boss, the insert is inserted into the step hole of the nail sleeve from the second end of the nail sleeve and sleeved on the core rod, the first end of the nail body is inserted into the step hole, and the second end of the nail body abuts against the drive nut; the first end of the nail sleeve forms a closing portion by lateral compression.

[0016] The characteristics and advantages of the present invention are:

[0017] The threaded pull-out nail, its nail sleeve, and the nail sleeve manufacturing method of the present invention divide the nail sleeve semi-finished product into a first length section, a second length section, and a third length section, and design the length of each length section, and then heat treat the first length section and the second length section at different heating temperatures. Since the heating temperature of the first length section is higher than the heating temperature of the second length section, the third length section is not heat treated, so that the strength of the first length section becomes lower and the plasticity becomes better. The length section is used to form the main deformation section of the nail sleeve, and expansion deformation occurs during the installation process of the threaded pull-out nail, reducing the installation driving force and resistance of the threaded pull-out nail, thereby facilitating the improvement of The second length segment has a stable installation effect, and the strength and plasticity of the first length segment are inferior to those of the first length segment. The length segment is used to form a transition deformation segment of the nail sleeve, which is convenient for forming the bell-shaped pier head of the nail sleeve. The third length segment can maintain high strength and is used as a supporting segment of the nail sleeve, so that it can bear the axial force applied by the core rod during the installation of the threaded nail. Therefore, the present invention can form a unique three-stage incremental structure of low strength-medium strength-high strength from the second end to the first end of the nail sleeve, so that the length segments of different strengths can play their due role, improve the quality stability of the product, and ensure that the pier head of the riveted installation of the threaded nail is in a bell tower shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a schematic structural diagram of the nail sleeve in the present invention.

[0020] Figure 2 It is the appearance diagram of the threaded nail puller in the present invention.

[0021] Figure 3 It is a cross-sectional view of the threaded nail extraction device in the present invention.

[0022] Figure 4 It is a cross-sectional view of the threaded nail after installation in the present invention.

[0023] Figure 5 It is the metallographic structure diagram of the main deformation section in the nail sleeve of the present invention.

[0024] Figure 6 It is the metallographic structure diagram of the transition deformation section in the nail sleeve of the present invention.

[0025] Figure 7 The figure is a metallographic structure diagram of the support section in the nail sleeve of the present invention.

[0026] In the figure:

[0027] 1. Nail sleeve; 11. Step hole; 12. Perforation; 13. Closing part; 14. Main deformation section; 15. Transition deformation section; 16. Support section; 2. Core rod; 21. Head boss; 22. Neck breaking groove; 3. Insert; 4. Nail body; 41. Guide cone; 42. Limiting platform; 5. Drive nut; 61. First length section; 62. Second length section; 63. Third length section; 7. Installation interlayer; 71. Outer side surface; 72. Inner side surface. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Implementation Method 1

[0030] like Figures 1 to 3 As shown, the present invention provides a method for manufacturing a nail sleeve, which is used to manufacture a nail sleeve 1. The first end of the nail sleeve 1 can form a closing portion 13 after the nail sleeve 1 is assembled with the core rod 2. The second end of the nail sleeve 1 is provided with a step hole 11 for installing an insert 3, and the length of the insert 3 is less than the length L0 of the step hole 11.

[0031] The outer wall surface of the nail sleeve 1 manufactured by the nail sleeve manufacturing method of the present invention is generally a cylindrical surface, that is, no closing portion 13 is formed, and the nail sleeve 1 is also formed with a through hole 12 that is connected to the step hole 11 and extends to the first end of the nail sleeve 1. When the finished nail sleeve 1 is assembled with the core rod 2, that is, the nail sleeve 1 is sleeved on the core rod 2, the first end of the nail sleeve 1 (that is, the end of the nail sleeve 1 abutting against the head boss 21 of the core rod 2) can be horizontally squeezed (that is, radially inwardly compressed) to form a closing portion 13 with increased strength and hardness at the first end of the nail sleeve 1. The outer diameter of the closing portion 13 is smaller than the outer diameter of the main body of the nail sleeve 1. The length of the closing portion 13 is not specifically limited and can be adjusted according to the outer diameter of the nail sleeve 1. For example, the larger the outer diameter of the nail sleeve 1, the longer the length of the closing portion 13 is, and the smaller the outer diameter of the nail sleeve 1 is, the shorter the length of the closing portion 13 is.

[0032] The method for manufacturing a nail sleeve of the present invention comprises the following steps: preparing a nail sleeve blank; processing a step hole 11 at one end of the nail sleeve blank to obtain a nail sleeve semi-finished product; dividing the nail sleeve semi-finished product into a first length section 61, a second length section 62 and a third length section 63 in sequence from one end of the nail sleeve semi-finished product close to the step hole 11 to the other end of the nail sleeve semi-finished product; wherein the length L1 of the first length section 61 is greater than the length l1 of the insert 3, the second length section 62 is connected to the first length section 61, and the length L3 of the third length section 63 is greater than the closing portion 1 3; the first length segment 61 of the semi-finished nail sleeve is heat-treated at a first heating temperature, and the second length segment 62 of the semi-finished nail sleeve is heat-treated at a second heating temperature; wherein the first heating temperature is higher than the second heating temperature; after the first length segment 61 and the second length segment 62 are heat-treated, the semi-finished nail sleeve is cryogenically treated, so that the first length segment 61 constitutes the main deformation segment 14 of the nail sleeve 1, the second length segment 62 constitutes the transition deformation segment 15 of the nail sleeve 1, and the third length segment 63 constitutes the supporting segment 16 of the nail sleeve 1.

[0033] The method for manufacturing a nail sleeve of the present invention divides the nail sleeve semi-finished product into a first length section 61, a second length section 62 and a third length section 63, and designs the length of each length section, and then heat-treats the first length section 61 and the second length section 62 at different heating temperatures. Since the heating temperature of the first length section 61 is higher than the heating temperature of the second length section 62, the third length section 63 is not heat-treated, so that the strength of the first length section 61 becomes lower and the plasticity becomes better. The main deformation section 14 of the nail sleeve 1 is formed by using the length section, and expansion deformation occurs during the installation process of the threaded nail, thereby reducing the installation driving force and resistance of the threaded nail, thereby facilitating the improvement of the thread. The second length segment 62 has a stable installation effect, and the strength and plasticity of the second length segment 62 are inferior to those of the first length segment 61. This length segment is used to form the transition deformation segment 15 of the nail sleeve 1, which is convenient for forming the bell-shaped pier head of the nail sleeve 1. The third length segment 63 can maintain high strength and is used as the supporting segment 16 of the nail sleeve 1, so that it can bear the axial force applied by the core rod 2 during the installation process of the threaded nail. Therefore, the present invention can form a unique three-stage increasing structure of low strength-medium strength-high strength from the second end to the first end of the nail sleeve 1, so that the length segments of different strengths can play their due role, improve the quality stability of the product, and ensure that the pier head of the riveted installation of the threaded nail is in a bell tower shape.

[0034] like Figures 1 to 3As shown, the prepared nail sleeve 1 is assembled with the core rod 2, the nail body 4, the insert 3 and the drive nut 5 to form a threaded screw. The first end of the core rod 2 is provided with a head boss 21. The nail sleeve 1, the nail body 4 and the drive nut 5 are sequentially sleeved on the core rod 2 from the second end of the core rod 2. The insert 3 is inserted into the step hole 11 of the nail sleeve 1 and sleeved on the core rod 2. The first end of the nail sleeve 1 abuts against the head boss 21. The first end of the nail body 4 is inserted into the step hole 11, and the second end of the nail body 4 abuts against the drive nut 5. In addition, a neck-breaking groove 22 is also provided on the core rod 2. Among them, a limiting platform 42 is provided at the second end of the nail body 4, and the limiting platform 42 abuts against the boss of the drive nut 5. A guide cone 41 is provided at the first end of the nail body 4, and the guide cone 41 is gradually set in the direction of the nail sleeve 1 to guide the insert 3 and the main deformation section 14 of the nail sleeve 1 to expand and deform.

[0035] Combination Figure 4 As shown, the installation process of the threaded pull-out nail is as follows: insert the assembled threaded pull-out nail into the installation hole from the outside of the installation interlayer 7 until the limiting platform 42 of the nail body 4 abuts against the outer side surface 71 of the installation interlayer 7, so that the nail sleeve 1, the insert 3 and the head boss 21 of the core rod 2 all pass through the installation hole and extend to the inner side of the installation interlayer 7, and then rotate the driving nut 5 to pull the core rod 2 outward, and the head boss 21 of the core rod 2 presses against the closing part 13 of the support section 16 of the nail sleeve 1 to drive the nail sleeve 1 to move outward (that is, move toward the side close to the installation interlayer 7), so that the nail sleeve 1 The main deformation section 14 and the insert 3 are gradually expanded, and the sleeve length on the nail body 4 is gradually increased, and then the core rod 2 is continuously pulled outward, so that the main deformation section 14 of the nail sleeve 1 abuts against the inner side surface 72 of the installation interlayer 7, and then the main deformation section 14 and the transition deformation section 15 of the nail sleeve 1 are deformed under the pressure of the inner side surface 73 of the installation interlayer 7 and the head boss 21 of the core rod 2 to form a large foot (i.e., pier head), so that the installation interlayer 7 is locked by the limiting platform 42 of the nail body 4 and the large bottom angle formed by the nail sleeve 1, and then the core rod 2 is broken from the breaking groove. Among them, the use of the insert 3 can reduce the friction resistance between the nail sleeve 1 and the nail body 4 and the core rod 2, and is conducive to expanding the deformation of the nail sleeve 1.

[0036] refer to Figure 1As shown, in an embodiment of the present invention, preparing a nail sleeve blank includes: using a tube body to cut and process into a nail sleeve blank; wherein the nail sleeve blank has an axially penetrating through hole. Specifically, the tube body is a hard stainless steel tube, and the tensile strength of the hard stainless steel tube is 800Mpa to 1050Mpa, ensuring that the support section 16 formed by the third length section 63 that is not subsequently heat treated has high strength. The length of the nail sleeve blank is substantially the same as the designed length of the nail sleeve 1. The inner diameter of the through hole is substantially the same as the designed inner diameter of the through hole 12 of the nail sleeve 1. Further, in the preparation step of the semi-finished nail sleeve, one end of the through hole of the nail sleeve blank is expanded by lathing to form a step hole 11, and the other end of the through hole constitutes a through hole 12. That is to say, the semi-finished nail sleeve before heat treatment is exactly the same in shape and size as the finished nail sleeve finally obtained by the nail sleeve manufacturing method of the present invention.

[0037] Combination Figures 1 to 3 As shown, in the embodiment of the present invention, the length of the first length segment 61 is L1, the length of the insert 3 is l1, and the relationship is: 0.5mm≤(L1-l1)≤2.0mm; the length of the third length segment 63 is L3, the length of the closing portion 13 is l2, and the relationship is: 1.5mm≤(L3-l2)≤5.5mm. The length of the second length segment 62 is L2, which is equal to the total length of the semi-finished nail sleeve (that is, the length L of the nail sleeve) minus the sum of the length L1 of the first length segment 61 and the length L3 of the third length segment 63.

[0038] Combination Figure 1 As shown, in an embodiment of the present invention, the first heating temperature is 950°C to 1050°C, and the second heating temperature is 850°C to 950°C. Preferably, the heating methods for heat treatment of the first length segment 61 and the second length segment 62 are both induction heating, that is, electromagnetic induction heating. The segmented heat treatment of the semi-finished nail sleeve by induction heating can ensure that the heating temperatures of the first length segment 61 and the second length segment 62 are accurate and do not affect each other, and can also avoid the third length segment 63 being heated and affecting its organization. It is suitable for the heat treatment of large quantities of semi-finished nail sleeves, which is beneficial to improve the manufacturing efficiency of large quantities of nail sleeves 1, and is also suitable for the heat treatment of small quantities of semi-finished nail sleeves, with low energy consumption and high cost performance, which is beneficial to reduce the manufacturing cost of small quantities of nail sleeves 1.

[0039] Specifically, heat treatment of the first length segment 61 includes: sleeve a first induction heating coil outside the first length segment 61 for induction heating; wherein the length of the first induction heating coil is equal to the length L1 of the first length segment 61. Heat treatment of the second length segment 62 includes: sleeve a second induction heating coil outside the second length segment 62 for induction heating; wherein the length of the second induction heating coil is equal to the length L2 of the second length segment 62.

[0040] refer to Figure 1 As shown, in an embodiment of the present invention, performing cryogenic treatment on the semi-finished nail sleeve product includes: placing the semi-finished nail sleeve product in a cold box for cryogenic treatment; wherein the cold box is filled with liquid nitrogen, and the temperature in the cold box is -90°C.

[0041] In addition, after heat treatment of the first length section 61 and the second length section 62 and before cryogenic treatment of the semi-finished nail sleeve, the method further includes: blowing inert gas to the semi-finished nail sleeve to rapidly cool the semi-finished nail sleeve, wherein the inert gas includes but is not limited to argon.

[0042] refer to Figure 1 As shown, in the embodiment of the present invention, the first length segment 61 and the second length segment 62 can be heat-treated separately and then blow-cooled separately, for example, the first length segment 61 is first heat-treated at a first heating temperature by the first induction heating coil, and then the semi-finished nail sleeve is blow-cooled, and then the second length segment 62 is heat-treated at a second heating temperature by the second induction heating coil, and then the semi-finished nail sleeve is blow-cooled. The first length segment 61 and the second length segment 62 can also be heat-treated at the same time and then blow-cooled at the same time, for example, the first induction heating coil is sleeved outside the first length segment 61, and the second induction heating coil is sleeved outside the second length segment 62, so that the first length segment 61 and the second length segment 62 are heat-treated at the corresponding heating temperature, and then the semi-finished nail sleeve is blow-cooled.

[0043] Before heat treating the first length section 61 and the second length section 62, the method further includes: cleaning the surface dirt of the nail sleeve semi-finished product; after deep freezing the nail sleeve semi-finished product, the method further includes: performing surface lubrication treatment on the nail sleeve semi-finished product; wherein the surface lubrication treatment includes but is not limited to coating the surface of the nail sleeve semi-finished product with aviation aluminum paint or molybdenum disulfide-based lubricant.

[0044] refer to Figure 1 As shown, in order to better understand and implement the nail sleeve manufacturing method of the present invention, two specific embodiments are provided:

[0045] In a specific embodiment, a nail sleeve 1 with an outer diameter of 5 mm and a length L of 10 mm is prepared, and the length l1 of the insert 3 configured for the nail sleeve 1 is 2.2 mm to 2.6 mm, and the length l2 of the preformed closing portion 13 is 0.5 mm to 1.5 mm. The length of the semi-finished nail sleeve is 10 mm, and the length L0 of the step hole 11 is 3.5 mm; the semi-finished nail sleeve is divided into a first length section 61 with a length L1 of 3.5 mm to 4.0 mm, a second length section 62 with a length L2 of 3 mm, and a third length section 63 with a length L3 of 3.0 mm to 3.5 mm from the end face of the first end where the step hole 11 is provided to the end face of the second end of the semi-finished nail sleeve in sequence; the first length section 61 of the semi-finished nail sleeve is heated to 1000° C. to 1150° C. by a first induction heating coil with a length of 3.5 mm to 4.0 mm, and then cooled by air blowing; the second length tube of the semi-finished nail sleeve is heated to 900° C. to 950° C. by a second induction heating coil with a length of 3 mm, and then cooled by air blowing; the semi-finished nail sleeve after heat treatment and cooling is placed in a cold box at -90° C. for deep cooling.

[0046] In another specific embodiment, a nail sleeve 1 with an outer diameter of 8 mm and a length L of 14 mm is prepared, and the length l1 of the insert 3 configured for the nail sleeve 1 is 3.6 mm to 3.9 mm, and the length l2 of the preformed closing portion 13 is 1.5 mm to 2.5 mm. The length of the semi-finished nail sleeve is 14 mm, and the length L0 of the step hole 11 is 4.5 mm; the semi-finished nail sleeve is divided into a first length section 61 with a length L1 of 4.5 mm to 5.0 mm, a second length section 62 with a length L2 of 2.5 mm to 3.0 mm, and a third length section 63 with a length L3 of 6.0 mm to 7.0 mm from the end face of the first end where the step hole 11 is provided to the end face of the second end of the semi-finished nail sleeve in sequence; the first length section 61 of the semi-finished nail sleeve is heated to 1000° C. to 1150° C. by a first induction heating coil with a length of 4.5 mm to 5.0 mm, and then cooled by air blowing; the second length tube of the semi-finished nail sleeve is heated to 900° C. to 950° C. by a second induction heating coil with a length of 2.5 mm to 3.0 mm, and then cooled by air blowing; the semi-finished nail sleeve after heat treatment and cooling is placed in a cold box at -90° C. for deep cooling.

[0047] The nail sleeve 1 obtained in the above two specific embodiments has a hardness of 156Hv for the main deformation section 14 corresponding to the first length section 61, a hardness of 256Hv for the transition deformation section 15 corresponding to the second length section 62, and a hardness of 350Hv for the support section 16 corresponding to the third length section 63. Figures 5 to 7It can be seen from the metallographic structures of each section that the main deformation section 14 and the transition deformation section 15 are both low-hardness austenite structures obtained after heat treatment. The main deformation section 14 has a small hardness value and the corresponding structure has large grains. The transition deformation section 15 has the second-best hardness and the corresponding grains are finer. The support section 16 has the highest hardness and the corresponding grains are relatively small and has a deformed martensite structure with high strength and hardness.

[0048] Implementation Method 2

[0049] like Figure 1 As shown, the present invention also provides a nail sleeve 1, which is made by a nail sleeve manufacturing method; the nail sleeve manufacturing method in this embodiment is the same as the nail sleeve manufacturing method in embodiment 1 in terms of specific structure, working principle and beneficial effects, which will not be repeated here. The second end of the nail sleeve 1 is provided with a step hole 11, and the nail sleeve 1 sequentially forms a main deformation section 14, a transition deformation section 15 and a support section 16 from the second end to the first end.

[0050] Implementation Method 3

[0051] like Figures 1 to 3 The present invention further provides a threaded nail extractor, comprising a nail sleeve 1. The specific structure, working principle and beneficial effects of the nail sleeve 1 in this embodiment are the same as those of the nail sleeve 1 in the second embodiment, and will not be repeated here.

[0052] The threaded screw also includes a core rod 2, a nail body 4, an insert 3 and a drive nut 5. The first end of the core rod 2 is provided with a head boss 21. The nail sleeve 1, the nail body 4 and the drive nut 5 are sequentially sleeved on the core rod 2 from the second end of the core rod 2. The first end of the nail sleeve 1 abuts against the head boss 21. The insert 3 is inserted into the step hole 11 of the nail sleeve 1 from the second end of the nail sleeve 1 and sleeved on the core rod 2. The first end of the nail body 4 is inserted into the step hole 11, and the second end of the nail body 4 abuts against the drive nut 5. The first end of the nail sleeve 1 is compressed laterally to form a closing portion 13. Among them, the second end of the nail body 4 is provided with a limiting platform 42, and the limiting platform 42 abuts against the boss of the drive nut 5.

[0053] The above are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A method for manufacturing a nail sleeve, characterized in that: Used to manufacture a nail sleeve, wherein the first end of the nail sleeve can form a closing portion after the nail sleeve is assembled with the core rod, and the second end of the nail sleeve is provided with a stepped hole for installing an insert, and the length of the insert is less than the length of the stepped hole; The nail sleeve manufacturing method comprises the following steps: Prepare nail sleeve blanks; Processing the step hole at one end of the nail sleeve blank to obtain a nail sleeve semi-finished product; The semi-finished nail sleeve is divided into a first length segment, a second length segment and a third length segment in sequence from one end of the semi-finished nail sleeve near the step hole to the other end of the semi-finished nail sleeve; wherein the length of the first length segment is greater than the length of the insert, the second length segment is connected to the first length segment, and the length of the third length segment is greater than the length of the closing portion; Heat-treating a first length section of the semi-finished nail sleeve product at a first heating temperature, and heat-treating a second length section of the semi-finished nail sleeve product at a second heating temperature; wherein the first heating temperature is higher than the second heating temperature; After the first length segment and the second length segment are heat treated, the nail sleeve semi-finished product is cryogenically treated, so that the first length segment constitutes the main deformation segment of the nail sleeve, the second length segment constitutes the transition deformation segment of the nail sleeve, and the third length segment constitutes the supporting segment of the nail sleeve.

2. The method for manufacturing a nail sleeve according to claim 1, characterized in that: The length of the first length segment is L1, and the length of the insert is l1, which has the relationship: 0.5 mm ≤ (L1-l1) ≤ 2.0 mm; The length of the third length segment is L3, and the length of the closing portion is l2, and they have the relationship: 1.5mm≤(L3-l2)≤5.5mm.

3. The method for manufacturing a nail sleeve according to claim 1, characterized in that: The first heating temperature is 950°C to 1050°C, and the second heating temperature is 850°C to 950°C.

4. The method for manufacturing a nail sleeve according to any one of claims 1 to 3, characterized in that: The heating methods for heat treating the first length segment and the second length segment are both induction heating.

5. The method for manufacturing a nail sleeve according to claim 4, characterized in that: The heat treatment of the first length segment includes: placing a first induction heating coil outside the first length segment for induction heating; wherein the length of the first induction heating coil is equal to the length of the first length segment; The heat treatment of the second length segment includes: placing a second induction heating coil outside the second length segment for induction heating; wherein the length of the second induction heating coil is equal to the length of the second length segment.

6. The method for manufacturing a nail sleeve according to claim 1, characterized in that: The preparing of the nail sleeve blank comprises: using a hard stainless steel pipe to obtain the nail sleeve blank; wherein the hard stainless steel pipe has a tensile strength of 800Mpa to 1050Mpa.

7. The method for manufacturing a nail sleeve according to claim 1, characterized in that: The cryogenic treatment of the semi-finished nail sleeve comprises: placing the semi-finished nail sleeve in a cold box for cryogenic treatment; wherein the cold box is filled with liquid nitrogen, and the temperature in the cold box is -90°C.

8. The method for manufacturing a nail sleeve according to claim 1, characterized in that: After the first length segment and the second length segment are heat treated and before the semi-finished nail sleeve product is cryogenically treated, the method further includes: blowing inert gas toward the semi-finished nail sleeve product to rapidly cool the semi-finished nail sleeve product.

9. The method for manufacturing a nail sleeve according to claim 1, characterized in that: Before heat treating the first length section and the second length section, the method further includes: cleaning the surface dirt of the nail sleeve semi-finished product; After the semi-finished nail sleeve product is subjected to deep cryogenic treatment, the method further comprises: performing surface lubrication treatment on the semi-finished nail sleeve product.

10. A nail sleeve, characterized in that: The nail sleeve is manufactured by the nail sleeve manufacturing method described in any one of claims 1 to 9; the second end of the nail sleeve is provided with a step hole, and the nail sleeve forms a main deformation section, a transition deformation section and a support section in sequence from the second end to the first end.

11. A threaded nail extractor, characterized in that: Including the nail sleeve as described in claim 10, the threaded nail also includes a core rod, a nail body, an insert and a drive nut, the first end of the core rod is provided with a head boss, the nail sleeve, the nail body and the drive nut are sequentially sleeved on the core rod from the second end of the core rod, the first end of the nail sleeve abuts against the head boss, the insert is inserted into the step hole of the nail sleeve from the second end of the nail sleeve and sleeved on the core rod, the first end of the nail body is inserted into the step hole, and the second end of the nail body abuts against the drive nut; the first end of the nail sleeve forms a closing portion by lateral compression.

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