CN103557219B - Light bolt fastening piece, its processing method and mould - Google Patents

Abstract

The invention relates to a lightweight bolt fastener for aerospace applications. The bus bar of the transition part is designed as a smooth curve approximately sinusoidal, the inclination angle of the cone section of the transition part is relatively small, the transition part is relatively short, and the structure is relatively reasonable; The screw hole is relatively short, which is convenient for installation, and also reduces the overall length of the bolt, thereby reducing weight; using the light bolt transition part car-rolling R mold, ingeniously strengthens the weak stress of the transition part , the mold of rolling R is simple, low in cost, easy to operate and higher in efficiency; the wrench pin used in conjunction with the light bolt fastener can bear a larger wrenching torque than the hexagonal wrench pin, and further reduces The length of the wrench pin is reduced, and the service life of the wrench pin is prolonged.

Description

Lightweight bolt fastener, its processing method and mold

technical field

The invention relates to a lightweight bolt fastener (also known as a high-lock bolt) for aerospace. The invention also relates to the processing method of the transition portion on the bolt fastener and the die for rolling R.

Background technique

In the field of aviation and aerospace, light bolt fasteners are widely used in the connection of airframe structures and important parts due to their light weight, high strength, and good fatigue performance.

Western developed countries started earlier in research and production in this field. At present, there are mainly LiSi in France, SPS in the United States and Alcoa, each of which has its own method for the shape, structure and processing technology of light bolt fasteners, and has formed some relatively mature patents. For example, Heck International Corporation, a subsidiary of Alcoa, applied for a patent named "Light Threaded Fasteners and Rolling Dies" on October 5, 1999, with a patent number of 99812743. The main features of its bolt fasteners are : "The thread blank has a large diameter shank and a small diameter shank, the small diameter shank is smoothly connected from the large diameter to the small diameter by a transition; the tapered section of the transition is relative to a straight line perpendicular to the axial direction of the bolt Extend an inclination angle, the inclination angle is between 25° and 35°, and in some cases, 25° to 55° can be used". The advantage of this patent is that the end of the light bolt fastener is ≤1.0P. The disadvantage is that the inclination angle of the cone section of the transition part is between 25° and 35°, and even a conservative design of 25° to 55° can be adopted. The length of the lightweight bolt fastener is relatively long, and the weight loss is relatively small.

In China, there are mainly fastener manufacturers such as Aerospace Seiko (Tianjin), 694 Factory, 3117 Factory, 3536 Factory, and 625 Institute. Among them, Aerospace Seiko (Tianjin) applied for a patent titled "High Lock Bolt with Groove End, Its Processing Method and Roller" on July 10, 2012, with the patent number 201210236979. Its main features are: "a A high-lock bolt with a groove ending, comprising a nut, a polished rod section, a threaded section and a finishing section, characterized in that: the finishing section is a groove, the circumferential surface of the groove is a conical surface, and the conical surface The small end of the conical surface is connected with the polished rod section, and the large end of the conical surface is connected with the threaded section. The connection between the groove, the polished rod section and the threaded section is a transition connection of an arc surface; the groove of the ending section is formed by roller rolling ". On April 21, 2008, Guizhou Aerospace Seiko (i.e. 3536 factory) applied for a patent named "High Lock Bolt" with a patent number of 200820300593. Its main features are: "a high lock bolt with a bolt head, It consists of a screw rod and a threaded section, and is characterized in that: an inner hexagonal hole is provided at the end of the threaded section."

To sum up, domestic and foreign fastener companies have mainly conducted research and applied for related patents on the structure of the transition section of the light bolt, the processing method of the transition section, the processing mold and the screw hole at the tail, etc., but are currently facing The problem of light bolt finishing design and its processing optimization (as shown in Figure 1).

At present, my country's aerospace industry is in a stage of vigorous development, and there is a huge demand for light bolt fasteners, but the import price is expensive, there is a problem of conversion between imperial and metric standards, and the delivery cycle cannot be guaranteed. In order to meet the requirements of the development and localization of aerospace, it is urgent for us to improve, optimize or design new fasteners to break through the technological blockade of foreign countries.

Contents of the invention

The present invention aims to provide a light-duty bolt fastener with reasonable structure, easy installation and sufficient weight reduction. The transition part of the fastener is relatively short, the inclination angle of the cone section is relatively small, and the structure of the transition part is reasonable; The wrench hole at the tail of the bolt has a large wrenching torque and a relatively short wrench hole, which facilitates installation and reduces the overall length of the bolt, thereby reducing weight. At the same time, the invention provides the turning-rolling R mold of the light bolt transition part, which strengthens the weak stress of the transition part, and the turning-rolling R mold has simple structure, low cost, easy operation and high efficiency. The invention also provides an installation tool matched with the light bolt fastener.

One of the technical measures adopted in the present invention is: the bus bar of the transition part of the light bolt is designed as a smooth curve approximately sinusoidal, and the inclination angle of the cone section of the transition part is adjusted accordingly. The specific technical scheme is as follows:

Lightweight bolt fasteners, consisting of a bolt head and a screw rod, the bolt head can be a flat head or a countersunk head, and can also be applied to bolts of any head shape; the screw rod includes a cylindrical smooth rod with one end starting from the bolt head There is a polished rod section at the top, a threaded section with external threads at the axial end of the screw, and a relatively short transition part smoothly transitioned between the polished rod section and the threaded section. The diameter of the polished rod section is greater than that of the threaded section, and the transition portion starts from the polished rod section with a large diameter and is connected with the root of the threaded section with a small diameter in a transition trend of gradually decreasing outer diameter.

The transition part is composed of the first arc segment, the second arc segment, the front cone segment, the third arc segment, and the rear cone segment, which are smoothly transitioned from the beginning to the end. The first arc segment has a relatively large radius, which starts at The end of the polished rod section extends radially inwards gradually to connect with the second arc section with a smaller radius, and the second arc section and the third arc section are separated by a front The conical segments are smoothly connected, and the end of the third arc segment extends radially outward gradually and is connected to a rear conical segment, which is connected to the adjacent end of the threaded segment via a conventional fillet transition.

The angle between the front cone section or its extension line and a straight line perpendicular to the bolt axis is the front cone section inclination angle At, and the angle range of the front cone section inclination angle At is 10°≤At<25° ;

The angle between the rear cone section or its extension line and a straight line parallel to the bolt axis is the rear cone section inclination angle A0, and the angle range of the rear cone section inclination angle A0 is 15°≤A0≤45° .

The second technical measure that the present invention adopts is: the wrenching hole at the bolt tail has been redesigned, and the conventional hexagonal wrenching hole is changed into a hexagonal torx wrench hole.

The bolt tail of the existing light-duty bolt fastener is provided with an inner hexagonal wrench hole, the influence of the depth and shape on the strength performance of the bolt cannot exceed the standard value, and it is required that no slippage will occur when the installation torque is reached. This conventional internal hexagonal wrench hole must reach a certain depth to ensure that it can carry sufficient wrenching torque, which will inevitably increase the length of the threaded section and the weight of the overall bolt; in order to minimize the thread length of the bolt and reach the bolt For the purpose of weight reduction, the present invention improves the original hexagonal wrench hole into a hexagonal torx wrench hole. The specific structure is six smooth arc-shaped clamping flaps that are prominent and evenly distributed in the circumferential direction. The hexagonal torx wrench hole of the clamping flap can carry a larger wrenching torque at a relatively short axial depth, thereby reducing the length of the bolt thread section and the wrench pin, achieving bolt weight reduction and extending the wrench pin. service life.

The third technical measure adopted by the present invention is: the transition part of the light bolt has a weak point of stress, which requires cold working to meet the physical properties. For this reason, the present invention provides a kind of processing method of light-duty bolt transition part, utilizes turning machine tool to carry out turning, then utilizes conventional rolling process to carry out rolling to transition part, namely adopts the processing technology of turning first and then rolling to transition part, The weak point of stress in the transition part is strengthened. A mold used in the lathing-then-rolling process includes a reverse turning tool 8 mounted on a tool bar 6 via a screw 7 , and a roller 10 mounted on a tool handle 13 via a bearing 11 and a roller 12 . The light-duty bolt 9 is clamped by a turning machine tool, and then R is reversed and then rolled to the size required by cold processing, which effectively strengthens the weak stress of the transition part. Compared with the rolling and rolling dies that cost tens of thousands of yuan, the rolling R mold has simple structure, low cost, easy operation and higher efficiency.

The fourth technical measure adopted by the present invention is to provide a mounting tool used in conjunction with the hexagon socket wrench hole at the tail of the light bolt of the present invention, the mounting tool has a mounting head 14, a wrench rod 15 and a wrench head 16. The wrench head 16 is changed from a conventional hexagonal structure to a hexagonal quincunx structure, which can carry a larger wrenching torque than the hexagonal wrench pin, and further reduces the length of the wrench pin and prolongs the wrench. pin life.

Description of drawings

Fig. 1 is a schematic diagram of light bolt structure;

Fig. 2 is a schematic diagram of the bus bar of the light bolt transition part and the inclination angle At of the front cone section Zt of the transition part and the inclination angle A0 of the ZO section of the rear cone section;

Figure 3-4 is a schematic diagram of the structure where the wrenching hole at the tail of the light bolt is a hexagonal torx hole;

Figure 5 is an enlarged schematic diagram of the light-duty bolt transition part where cold working is required to meet the physical properties;

Fig. 6 is a schematic diagram of the mold of the light bolt transition part turning-rolling R;

7-8 are structural schematic diagrams of the hexagonal quincunx wrench pin.

Detailed ways

The specific embodiments of the present invention are given below with reference to the accompanying drawings, which are used to further describe the structure of the present invention.

Example 1

The present invention will be further elaborated below in conjunction with the accompanying drawings. As shown in FIG. 1 , the present invention provides a lightweight bolt fastener, which consists of a bolt head 1 , a polished rod section 2 , a transition section 3 and a threaded section 4 . The transition part 3 starts from the large-diameter polished rod section 2 and is connected with the root of the small-diameter threaded section 4 in a transition trend of gradually decreasing outer diameter. In the present invention, the generatrix of the light bolt transition part 3 (that is, the transition line from the proximal end of the maximum clamping length on the polished rod section to the beginning of the complete thread on the threaded section) is designed to be a smooth curve approximately sinusoidal, by the first Arc section L1, second arc section L2, front cone section Zt, third arc section L3, and rear cone section ZO are formed by a smooth transition from the beginning to the end. The first arc section L1 has a relatively large radius and starts from the polished rod The end of the segment and gradually radially extends inward to connect with the second arc segment L2 with a smaller radius, and the second arc segment L2 and the third arc segment L3 are cut between the two arc segments by an inner common tangent The front cone segment Zt is smoothly connected, the end of the third arc segment L3 gradually extends radially outward and is connected with the rear cone segment ZO, and the rear cone segment ZO is connected to the adjacent threaded segment through a conventional fillet transition end. The inclination angle At of the front cone section Zt of the transition part 3 (the angle between the front cone section Zt or its extension line and a straight line perpendicular to the bolt axis) is 10°, and the inclination angle A0 of the rear cone section ZO (rear cone section The angle between ZO or its extension line and a straight line parallel to the bolt axis) is 15°, as shown in Figure 2. When the dimensions of R2, R3 and R4 are constant, if At is too large or A0 is too small, the axial length of the transition part 3 is relatively long, which is not conducive to reducing the bolt length and achieving the purpose of bolt weight reduction; if At is too small, the busbar of the transition part 3 The front cone section Zt cannot be smoothly formed, and the rear cone section ZO of the busbar of the transition part 3 is too large to be rolled and threaded, which is prone to defects such as folding, flanging and cracks.

Figures 3 to 4 are schematic diagrams showing that the wrenching hole 5 at the tail of the light bolt is a hexagonal torx hole. The current light-duty bolts (whether domestic or foreign) have hexagonal holes at the tail. Because the wrenching torque is relatively small and easy to slip, the hexagonal holes are relatively deep, which has a certain impact on the load-bearing strength of light-duty bolts. The screwing hole at the tail of the light bolt is designed as a hexagonal torx hole. The specific structure is six smooth arc-shaped clamping flaps that are prominent and evenly distributed in the circumferential direction. The hexagonal torx screwing hole with the arc-shaped clamping flaps can The relatively short axial depth bears a larger wrenching torque, thereby reducing the length of the bolt thread and the length of the wrench pin, reducing the weight of the bolt and prolonging the service life of the wrench pin.

Fig. 5 is an enlarged schematic diagram of the transition part of the light bolt that requires cold working to meet the physical properties, that is, the transition part has a stress weak point that requires cold working to meet the physical properties. For this reason, the present invention provides a kind of mold that carries out car-rolling R process at light bolt transition part, as shown in Figure 6, by tool bar 6, screw 7, reverse turning tool 8, roller 10, bearing 11, roller 12 and handle of a knife 13 forms. The light-duty bolt 9 is clamped by a turning machine tool, and then R is reversed and then rolled to the size required by cold processing, which effectively strengthens the weak stress of the transition part. Compared with the rolling and rolling dies that cost tens of thousands of yuan, the rolling R mold has simple structure, low cost, easy operation and higher efficiency.

Figures 7 to 8 are schematic diagrams of hexagonal torx wrench pins, which are wrench pins used in conjunction with the hexagonal torx wrench holes of the light bolts. Usually the wrench pin is clamped on the light-duty bolt installation tool. The specific structure is six smooth arc-shaped clamping flaps that protrude and are evenly distributed in the circumferential direction. When installing light-duty bolt fasteners, they are used to fix Light bolts are not turned. Compared with the hexagonal wrench pin, the hexagonal wrench pin can carry a larger wrenching torque, further reduces the length of the wrench pin, and prolongs the service life of the wrench pin.

Example 2

The difference between this embodiment and embodiment 1 is that

The angle between the front cone section or its extension line and a straight line perpendicular to the bolt axis is the front cone section inclination angle At, and its angle range is 24 °; the rear cone section or its extension line is parallel to The included angle between a straight line in the axial direction of the bolt is the inclination angle A0 of the rear cone section, and the angle range thereof is 45°.

Example 3

The difference between this embodiment and embodiment 1 is that

The included angle between the front cone section or its extension line and a straight line perpendicular to the bolt axis is the front cone section inclination angle At, and its angle range is 15 °; the rear cone section or its extension line is parallel to The included angle between a straight line in the axial direction of the bolt is the inclination angle A0 of the rear cone section, and the angle range thereof is 25°.

In summary, the present invention provides four technical measures, so that the inclination angle of the cone section is relatively small, the transition part is relatively short, the length of the bolt is reduced, the transition part is a smooth curve approximately sinusoidal, and the structure is more reasonable; the bolt tail The hexagonal plum blossom-shaped wrench hole has a large wrenching torque and relatively short wrench hole, which facilitates installation and reduces the overall length of the bolt, thereby reducing weight; the light bolt transition part car-rolled R The die, which ingeniously strengthens the weak stress of the transition part, the die of rolling R is simple, low in cost, easy to operate and higher in efficiency; The pin can carry a larger wrenching torque, further reduces the length of the wrench pin, and prolongs the service life of the wrench pin.

Claims (5)

1. light bolt fastening piece, is made up of bolt head, polished rod section, transition part and thread section, it is characterized in that: the busbar of described transition part is the smoothed curve in near-sinusoidal, transition part inner cone section Zt tilt anglethe angular range of At is 10 °≤At < 25 °, transition part rear cone section ZO inclines oblique anglethe angular range of A0 is 15 °≤A0≤45 °;

Described transition part is formed by connecting by the first segmental arc, the second segmental arc, inner cone section, the 3rd segmental arc, rear cone section head and the tail rounding off, described first segmental arc has relatively large radius, its end starting from polished rod section also radially extends to gradually and is connected with second segmental arc with small radii, be smoothly connected by the inner cone section be cut between two segmental arcs public between described second segmental arc and the 3rd segmental arc, the end of described 3rd segmental arc gradually outward radial extends and is connected with rear cone section, and described rear cone section is connected to the abutting end of thread section via the round-corner transition of routine;

Described transition part inner cone section tilt angleat refer to perpendicular to bolt axis to straight line and angle between transition part inner cone section or its line stretcher;

Described transition part rear cone section tilt anglea0 refer to be parallel to bolt axis to straight line and angle between the rear cone section of transition part or its line stretcher.

2. light bolt fastening piece as claimed in claim 1, is characterized in that: the twisting hole of described thread section afterbody is designed to interior hexagonal plum blossom hole;

Described interior hexagonal plum blossom holeconcrete structure is outstanding, be distributed in circumferencial direction six smooth arcuation clamping lobes.

3. light bolt fastening piece as claimed in claim 1, is characterized in that described bolt head is the flat globular model of plane or the countersunk head shape of band tapering.

4. the method for the transition part of a processing light bolt fastening piece as claimed in claim 1, the processing technology of rolling after it is characterized in that adopting first car, namely turning class lathe is first utilized to carry out turning, then utilize conventional technique for rolling to carry out rolling to transition part, make it to be cold working to the weak part of transition part stress to meet its physical property requirements.

5. be applied to a mould for method described in claim 4, it is characterized in that comprising the anti-lathe tool be installed on by screw on knife bar, and be installed on the roller on handle of a knife by bearing and roller bearing.