阅读说明：本技术 一种螺栓热锻设备及制备工艺 (Bolt hot forging equipment and preparation process ) 是由 曾晖 汪豪豪 张楠楠 杨照军 陈元 于 2020-04-21 设计创作，主要内容包括：本发明属于螺栓热锻技术领域,尤其是一种螺栓热锻设备,现提出如下方案,包括进料输送组件、热锻组件和退火处理组件,所述退火处理组件包括降温保持机构和升温保持机构,所述降温保持机构和升温保持机构中间的底部连接有对接管,降温保持机构和升温保持机构之间安装有转运机构,降温保持机构包括与对接管连通的箱体,箱体远离对接管的一端上方安装有与其连通的伸入管,伸入管的内部安装沿其长度方向等距设置的第一导向单元。本发明实现了螺栓热锻胚料退火过程的连续性生产,能够将退火降温的余热利用在退火升温阶段,实现螺栓热锻的连续性生产,提高螺栓生产效率和自动化程度,减小占地空间,提升效率。(The invention belongs to the technical field of bolt hot forging, and particularly provides a bolt hot forging device which comprises a feeding conveying assembly, a hot forging assembly and an annealing treatment assembly, wherein the annealing treatment assembly comprises a cooling maintaining mechanism and a heating maintaining mechanism, a butt joint pipe is connected to the bottom of the middle of the cooling maintaining mechanism and the heating maintaining mechanism, a transfer mechanism is arranged between the cooling maintaining mechanism and the heating maintaining mechanism, the cooling maintaining mechanism comprises a box body communicated with the butt joint pipe, an extension pipe communicated with the box body is arranged above one end, far away from the butt joint pipe, of the box body, and first guide units which are equidistantly arranged along the length direction of the extension pipe are arranged in the extension pipe. The invention realizes the continuous production of the annealing process of the bolt hot forging blank, can utilize the afterheat of annealing cooling in the annealing heating stage, realizes the continuous production of the bolt hot forging, improves the production efficiency and the automation degree of the bolt, reduces the occupied space and improves the efficiency.)

1. The utility model provides a bolt hot forging equipment, includes feeding conveyor components, hot forging subassembly (1) and annealing processing subassembly, a serial communication port, annealing processing subassembly includes cooling retaining mechanism (2) and intensification retaining mechanism (3), the bottom in the middle of cooling retaining mechanism (2) and intensification retaining mechanism (3) is connected with butt joint pipe (8), install transfer mechanism (9) between cooling retaining mechanism (2) and the intensification retaining mechanism (3), cooling retaining mechanism (2) include box (201) with butt joint pipe (8) intercommunication, box (201) are kept away from the one end top of butt joint pipe (8) and are installed rather than the pipe (12) that stretches into of intercommunication, the internally mounted of stretching into pipe (12) is along first guide unit (5) that its length direction equidistance set up, the opening part top of stretching into pipe (12) is installed conversion mechanism (4), the internally mounted of box (201) has two sets of second guide unit (6) that the equidistance set up along its horizontal direction, a plurality of groups of third guide units (7) which are arranged at equal intervals along the horizontal direction are arranged between the two groups of second guide units (6), the fourth guide units (11) which are arranged at equal intervals along the vertical direction of the box body (201) are arranged at one ends, close to the extending pipes (12), of the two groups of second guide units (6), and the heat conduction coil pipes (10) of the spiral structures which are distributed at equal intervals along the height direction of the heat conduction coil pipes are arranged inside the box body (201).

2. The bolt hot forging equipment according to claim 1, wherein the transfer mechanism (9) comprises two groups of chains (901) which are arranged in parallel and are of an annular structure, connecting rods (902) which are arranged at equal intervals along the length direction of the two groups of chains (901) are fixedly connected between the two groups of chains (901), one end of each connecting rod (902) is fixedly connected with a clamping plate (903), one end, far away from the connecting rods (902), of each clamping plate (903) is provided with a mounting groove (904) which is of a long strip-shaped structure, two groups of movable plates (905) are slidably connected inside the mounting groove (904), one end, far away from each other, of each movable plate (905) is fixedly connected with a spring fixedly connected with the inner side wall of the mounting groove (904), one side, close to each other, of each movable plate (905) is provided with two groups of clamping plates (906) which are distributed along.

3. The bolt hot forging equipment according to claim 1, wherein the conversion mechanism (4) comprises a linear module (401) fixedly connected with the inner side wall of the top of the extension pipe (12), the linear module (401) is arranged along the length direction of the extension pipe (12), a fixing plate (402) vertically arranged with the length direction of the linear module is fixedly connected with the bottom output end of the linear module (401), a rotating shaft (403) arranged along the length direction of the linear module (401) is movably sleeved on the fixing plate (402), a clamping jaw air cylinder (404) is fixedly connected with one end of the rotating shaft (403), and a first motor fixedly connected with the fixing plate (402) is installed at the other end of the rotating shaft (403).

4. The bolt hot forging equipment according to claim 1, wherein the first guide unit (5) comprises rotating rollers which are arranged at equal intervals along the box body (201) and movably sleeved with the box body (201), chain wheels which are linked with the chain (901) are fixedly sleeved on the outer rings of the rotating rollers, the first guide unit (5) is consistent with the second guide unit (6), the third guide unit (7) and the fourth guide unit (11) in structure, the number of the third guide unit (7) is at least 2, the rotating rollers on the fourth guide unit (11) are distributed along the vertical direction, the rotating rollers on the first guide unit (5), the rotating rollers on the second guide unit (6) and the rotating rollers on the third guide unit (7) are distributed along the horizontal direction, and a second motor is installed at one end of each rotating roller, which extends out of the box body (201).

5. The bolt hot forging equipment according to claim 1, wherein the cooling maintaining mechanism (2) and the heating maintaining mechanism (3) are consistent in structure and symmetrically distributed along the butt joint pipe (8), an air cylinder is fixedly connected to the inner side wall of the extension pipe (12), a push rod with a conical structure at the front end is installed at the output end of the air cylinder, the push rod is located between the two groups of clamping plates (906) of the transfer mechanism (9), and a cooling coil is installed inside the butt joint pipe (8).

6. The bolt hot forging equipment according to claim 1, wherein a feeding end of the uppermost heat conducting coil (10) of the cooling and maintaining mechanism (2) is communicated with a discharging end of the lowermost heat conducting coil (10) of the warming and maintaining mechanism (3) through a conduit, a discharging end of the lowermost heat conducting coil (10) of the cooling and maintaining mechanism (2) is communicated with a feeding end of the uppermost heat conducting coil (10) of the warming and maintaining mechanism (3), a discharging end of the heat conducting coil (10) above the cooling and maintaining mechanism (2) is communicated with a feeding end of the heat conducting coil (10) below the cooling and maintaining mechanism, a discharging end of the heat conducting coil (10) above the warming and maintaining mechanism (3) is communicated with a feeding end of the heat conducting coil (10) below the warming and maintaining mechanism, a liquid pump is installed on the conduit, and a heat pipe is installed inside the warming and maintaining mechanism (3).

7. A bolt hot forging preparation process is characterized by comprising the following steps;

s1, preparing a straight strip, conveying the strip to a hot forging component (1) for hot forging after material breaking through a feeding conveying component, wherein the feeding conveying component adopts a stepped automatic feeding device and then is placed into a forging die of the hot forging component (1) for hot forging forming to obtain a blank, a middle superaudio induction heater device arranged at the front end of the hot forging component (1) is used for heating, the temperature is controlled to be 900 ℃ plus materials during heating, the heat preservation time is 3-5S, and the frequency is 220 kHz plus materials 250 kHz;

s2 annealing the blank, taking the blank through the conversion mechanism (4), then placing the blank on two groups of clamping plates (906) on the transfer mechanism (9), carrying out temperature reduction and heat preservation on the blank through the temperature reduction and heat preservation mechanism (2) and the temperature rise and heat preservation mechanism (3) in sequence under the transportation of the transfer mechanism (9), wherein the annealing temperature is adjusted to 380 ℃ plus 340 ℃, the heat preservation is 20-40min, the blank is cooled to 260 ℃ plus 250 ℃ in the butt joint pipe (8), the temperature is increased to 450 ℃ plus 400 ℃ when being conveyed to the temperature rise and heat preservation mechanism (3), the heat preservation is 5-10min, the blank output from the temperature rise and heat preservation mechanism (3) is cooled to 210 ℃ plus 200 ℃, and standing is 1-2 h;

s3 is sequentially subjected to alkali washing, water washing, acid washing, water washing, phosphorization and water washing, and finally surface phosphorization treatment to obtain the prepared bolt.

Technical Field

The invention relates to the technical field of bolt hot forging, in particular to bolt hot forging equipment and a preparation process.

Background

In a plurality of large-scale construction projects or traffic construction projects, bolts required by the large-scale machine cannot be met by common bolts, so that hot-forged bolts appear at this time, the bolts with high strength can meet the requirements of the large-scale machine, annealing treatment is required in the process of producing the hot-forged bolts, the operation of the existing annealing mode is unchanged, and the continuous production capacity is poor, so that bolt hot-forging equipment and a bolt hot-forging preparation process are required.

Disclosure of Invention

The bolt hot forging equipment and the preparation process provided by the invention solve the problems in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a bolt hot forging device comprises a feeding conveying assembly, a hot forging assembly and an annealing treatment assembly, wherein the annealing treatment assembly comprises a cooling retaining mechanism and a heating retaining mechanism, the bottom between the cooling retaining mechanism and the heating retaining mechanism is connected with a butt pipe, a transfer mechanism is installed between the cooling retaining mechanism and the heating retaining mechanism, the cooling retaining mechanism comprises a box body communicated with the butt pipe, an extension pipe communicated with the box body is installed above one end of the box body, which is far away from the butt pipe, a first guide unit is installed inside the extension pipe and is equidistantly arranged along the length direction of the extension pipe, a conversion mechanism is installed above an opening of the extension pipe, two groups of second guide units are installed inside the box body and are equidistantly arranged along the horizontal direction of the extension pipe, a plurality of groups of third guide units are installed between the two groups of second guide units and are equidistantly arranged along the horizontal direction, and a fourth guide unit is installed at one end of the two groups of second guide units, which is near the extension pipe, the inside of box is installed along its direction of height equidistance distribution's helical structure's heat conduction coil pipe.

Preferably, the transport mechanism includes two sets of parallel arrangement's loop configuration's chain, the rigid coupling has the connecting rod that sets up along its length direction equidistance between two sets of chains, the one end rigid coupling of connecting rod has the grip block, the mounting groove of rectangular shape structure is seted up to the one end that the connecting rod was kept away from to the grip block, the inside sliding connection of mounting groove has two sets of fly leafs, the one end rigid coupling that two sets of fly leafs were kept away from each other has the spring with the mounting groove inside wall consolidation, two sets of splint that distribute along vertical direction are installed to one side that two sets of fly leafs are close to each other.

Preferably, the shifter includes and stretches into the sharp module of tub top inside wall rigid coupling, and sharp module sets up along the length direction who stretches into the pipe, and the bottom output rigid coupling of sharp module has the fixed plate rather than the perpendicular setting of length direction, and the fixed plate activity cup joints the pivot that sets up along sharp module length direction, and the one end rigid coupling of pivot has the clamping jaw cylinder, and the first motor with the fixed plate rigid coupling is installed to the other end of pivot.

Preferably, first guide unit includes the live-rollers that sets up along the box equidistance, and the live-rollers cup joints with the box activity, the fixed sprocket that links with the chain that has cup jointed in outer lane of live-rollers, first guide unit and second guide unit, third guide unit and fourth guide unit's structure is unanimous, the quantity of third guide unit is 2 groups at least, the live-rollers on the fourth guide unit distributes along vertical direction, the live-rollers on the first guide unit, the live-rollers on the second guide unit and the live-rollers on the third guide unit all distribute along the horizontal direction, the second motor is installed to the one end that the live-rollers stretches out the box.

Preferably, cooling retaining mechanism and intensification retaining mechanism structure are unanimous and along the butt joint pipe symmetric distribution, stretch into intraductal lateral wall rigid coupling and have the cylinder, and the push rod that the front end is conical structure is installed to the cylinder output, and the push rod is located the position between two sets of splint of transport mechanism, and butt joint pipe internally mounted has cooling coil.

Preferably, the feed end of the uppermost heat-conducting coil of the cooling and maintaining mechanism is communicated with the discharge end of the lowermost heat-conducting coil of the warming and maintaining mechanism through a guide pipe, the discharge end of the lowermost heat-conducting coil of the cooling and maintaining mechanism is communicated with the feed end of the uppermost heat-conducting coil of the warming and maintaining mechanism, the discharge end of the upper heat-conducting coil of the cooling and maintaining mechanism is communicated with the feed end of the adjacent lower heat-conducting coil, the discharge end of the upper heat-conducting coil of the warming and maintaining mechanism is communicated with the feed end of the adjacent lower heat-conducting coil, a liquid pump is installed on the guide pipe, and an auxiliary heat pipe is installed.

A bolt hot forging preparation process comprises the following steps;

s, preparing a straight strip material, conveying the strip material to a hot forging assembly for hot forging through a feeding conveying assembly after the strip material is cut off, wherein the feeding conveying assembly adopts a stepped automatic feeding device and then is placed into a forging die of the hot forging assembly for hot forging forming to obtain a blank, wherein a middle superaudio induction heater device arranged at the front end of the hot forging assembly is used for heating, the temperature is controlled to be 800-plus 900 ℃ during heating, the heat preservation time is 3-5S, and the frequency is 220-plus 250 kHz;

s2, annealing the blank, taking the blank through a conversion mechanism, then placing the blank on two groups of clamping plates on a transfer mechanism, transporting the blank along the transfer mechanism, sequentially carrying out cooling and heat preservation through a cooling and holding mechanism and a heating and heat preservation through a heating and holding mechanism, wherein the annealing temperature is adjusted to be 380 ℃ plus one material and is kept for 20-40min, cooling to be 260 ℃ plus one material in a butt joint pipe, heating to be 450 ℃ plus one material when transporting to the heating and holding mechanism, keeping the temperature for 5-10min, cooling the blank output from the heating and holding mechanism to be 210 ℃ plus one material 200 ℃ plus one material, and standing for 1-2 h;

s3 is sequentially subjected to alkali washing, water washing, acid washing, water washing, phosphorization and water washing, and finally surface phosphorization treatment to obtain the prepared bolt.

In the present invention,

through the hot forging subassembly that sets up, cooling retaining mechanism, the box, intensification retaining mechanism, the shifter, the straight line module, the fixed plate, the apparatus further comprises a rotating shaft, the clamping jaw cylinder, first guide unit, the second guide unit, the third guide unit, the butt joint pipe, transport mechanism, the chain, the connecting rod, the grip block, the mounting groove, the fly leaf, splint, the pull rod, the heat conduction coil pipe, fourth guide unit and the pipe that stretches into, make this design realize the continuity production of bolt hot forging stock annealing process, can be in annealing intensification stage with the waste heat utilization of annealing cooling, realize the continuity production of bolt hot forging, improve bolt production efficiency and degree of automation, reduce occupation of land space, the lifting efficiency.

Drawings

FIG. 1 is a schematic structural diagram of an annealing treatment assembly of a bolt hot forging device according to the present invention;

FIG. 2 is a schematic structural view of a bolt hot forging apparatus according to the present invention;

FIG. 3 is a partially enlarged schematic structural view of a bolt hot forging apparatus according to the present invention;

FIG. 4 is a schematic structural diagram of a transfer mechanism of a bolt hot forging device according to the present invention

Fig. 5 is a schematic structural diagram of a bolt hot forging device conversion mechanism provided by the invention.

In the figure: the device comprises a hot forging assembly 1, a cooling holding mechanism 2, a box 201, a heating holding mechanism 3, a conversion mechanism 4, a 401 linear module, a 402 fixing plate, a 403 rotating shaft, a 404 clamping jaw air cylinder, a 5 first guide unit, a 6 second guide unit, a 7 third guide unit, an 8 butt joint pipe, a 9 transfer mechanism, a 901 chain, a 902 connecting rod, a 903 clamping plate, a 904 mounting groove, a 905 movable plate, a 906 clamping plate, a 907 pull rod, a 10 heat conducting coil pipe, a 11 fourth guide unit and a 12 extension pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1-5, a bolt hot forging device comprises a feeding conveying assembly, a hot forging assembly 1 and an annealing treatment assembly, wherein the annealing treatment assembly comprises a cooling retaining mechanism 2 and a heating retaining mechanism 3, a butt joint pipe 8 is connected to the bottom between the cooling retaining mechanism 2 and the heating retaining mechanism 3, a transfer mechanism 9 is installed between the cooling retaining mechanism 2 and the heating retaining mechanism 3, the cooling retaining mechanism 2 comprises a box 201 communicated with the butt joint pipe 8, an extension pipe 12 communicated with the box 201 is installed above one end of the box 201 far away from the butt joint pipe 8, first guide units 5 equidistantly arranged along the length direction of the extension pipe 12 are installed inside the extension pipe 12, a conversion mechanism 4 is installed above an opening of the extension pipe 12, two groups of second guide units 6 equidistantly arranged along the horizontal direction of the box 201 are installed inside the box 201, a plurality of groups of third guide units 7 equidistantly arranged along the horizontal direction are installed between the two groups of second guide units 6, the two sets of second guiding units 6 are provided with fourth guiding units 11 arranged along the vertical direction of the box 201 at equal intervals near one end of the extending pipe 12, and the box 201 is internally provided with heat conducting coil pipes 10 distributed along the height direction at equal intervals and in a spiral structure.

Further, transport mechanism 9 includes two sets of parallel arrangement's loop configuration's chain 901, the rigid coupling has the connecting rod 902 that sets up along its length direction equidistance between two sets of chains 901, the one end rigid coupling of connecting rod 902 has grip block 903, the mounting groove 904 of rectangular shape structure is seted up to the one end that connecting rod 902 was kept away from to grip block 903, the inside sliding connection of mounting groove 904 has two sets of fly leafs 905, the one end rigid coupling that two sets of fly leafs 905 kept away from each other has the spring with the mounting groove 904 inside wall consolidation, two sets of splint 906 that distribute along vertical direction are installed to the one side that two sets of fly leafs 905 are close to each other, two sets of splint 906's.

Particularly, the conversion mechanism 4 includes a linear module 401 fixedly connected to the inner side wall of the top of the extension pipe 12, the linear module 401 is disposed along the length direction of the extension pipe 12, a fixing plate 402 vertically disposed along the length direction is fixedly connected to the bottom output end of the linear module 401, a rotating shaft 403 disposed along the length direction of the linear module 401 is movably sleeved on the fixing plate 402, a clamping jaw cylinder 404 is fixedly connected to one end of the rotating shaft 403, and a first motor fixedly connected to the fixing plate 402 is mounted at the other end of the rotating shaft 403.

It is worth to say that, the first guiding unit 5 includes the live-rollers that set up along box 201 equidistance, and the live-rollers and box 201 activity cup joint, the outer lane of live-rollers is fixed to cup joint the sprocket that links with chain 901, first guiding unit 5 and second guiding unit 6, the structure of third guiding unit 7 and fourth guiding unit 11 is unanimous, the quantity of third guiding unit 7 is 2 groups at least, the quantity that is arranged in between cooling retention mechanism 2 and the heating retention mechanism 3 of third guiding unit 7 selects according to annealing time length, the live-rollers on the fourth guiding unit 11 distributes along the vertical direction, the live-rollers on first guiding unit 5, the live-rollers on second guiding unit 6 and the live-rollers on third guiding unit 7 all distribute along the horizontal direction, the live-rollers stretch out the one end of box 201 and install the second motor.

In addition, cooling retaining mechanism 2 and 3 structures of intensification retaining mechanism are unanimous and along 8 symmetric distributions of butt joint pipe, and it has the cylinder to stretch into 12 inside wall rigid couplings of pipe, and the push rod that the front end is conical structure is installed to the cylinder output, and the push rod is located the position between two sets of splint 906 of transport mechanism 9, and 8 internally mounted have cooling coil to butt joint pipe.

Besides, the feed end of the heat conducting coil 10 at the top of the cooling maintaining mechanism 2 is communicated with the discharge end of the heat conducting coil 10 at the bottom of the heating maintaining mechanism 3 through a guide pipe, the discharge end of the heat conducting coil 10 at the bottom of the cooling maintaining mechanism 2 is communicated with the feed end of the heat conducting coil 10 at the top of the heating maintaining mechanism 3, the discharge end of the heat conducting coil 10 at the top of the cooling maintaining mechanism 2 is communicated with the feed end of the heat conducting coil 10 at the adjacent lower side, the discharge end of the heat conducting coil 10 at the top of the heating maintaining mechanism 3 is communicated with the feed end of the heat conducting coil 10 at the adjacent lower side, a liquid pump is installed on the guide pipe, and the.

A bolt hot forging preparation process comprises the following steps;

s1, preparing a straight strip, conveying the strip to the hot forging component 1 for hot forging after material breaking through the feeding conveying component, wherein the feeding conveying component adopts a stepped automatic feeding device and then is placed into a forging die of the hot forging component 1 for hot forging forming to obtain a blank, a middle superaudio induction heater device arranged at the front end of the hot forging component 1 is used for heating, the temperature is controlled to be 800-900 ℃, the heat preservation time is 3-5S, and the frequency is 220-250 kHz;

s2 annealing the blank, fetching the blank by the conversion mechanism 4, when fetching, the linear module 401 extends into the hot forging component 1, from the clamp on the hot forging component 1, then the clamping jaw cylinder 404 is started to clamp the hot forged blank, then the blank is conveyed to the inner part of the extension pipe 12 on the cooling and holding mechanism 2 by the linear module 401, simultaneously when the clamping plate 903 on the transfer mechanism 9 moves to the position of the push rod on the extension pipe 12, the cylinder on the push rod is started to extend the push rod between the two groups of clamping plates 906 on the clamping plate 903, the clamping plates 906 are spread, then the first motor on the conversion mechanism 4 is started, the clamping jaw cylinder 404 rotates 90 degrees to move the blank to the horizontal state, then the linear module 401 conveys the blank to the position close to the push rod, the blank is positioned between the two groups of clamping plates 906, the air pipe is closed, and the push rod returns to the initial position, clamping the blank by a clamping plate 906 under the action of a spring, starting a clamping jaw air cylinder 404, loosening the clamped blank by a clamping jaw on the clamping jaw air cylinder 404, sequentially placing the hot-forged blank on a clamping plate 903 on a transfer mechanism 9, then sequentially passing through a cooling and maintaining mechanism 2 along with the transportation of the transfer mechanism 9 for cooling and heat preservation and a heating and heat preservation mechanism 3 for heating and heat preservation, wherein the annealing temperature is adjusted to be 380 ℃ plus 340 ℃, the heat preservation is 20-40min, the blank is cooled to be 260 ℃ plus 250 ℃ in a butt joint pipe 8, the temperature is increased to be 450 ℃ when being conveyed to the heating and maintaining mechanism 3, the heat preservation is 5-10min, the blank output from the heating and maintaining mechanism 3 is cooled to be 210 ℃ plus 200 ℃, and standing is 1-2 h;

when the temperature is reduced, a liquid pump on the guide pipe is started, heat conducting oil with a coil pipe 10 on the temperature reduction keeping mechanism 2 is conveyed to the temperature rise keeping mechanism 3, so that the preheating emitted by temperature reduction is conveyed to the temperature rise keeping mechanism 3, the preheating is recycled, and an auxiliary heat pipe is utilized for auxiliary heating in the temperature rise keeping mechanism 3;

s3 sequentially carrying out alkali washing, water washing, acid washing, water washing, phosphating and water washing, and finally carrying out surface phosphating treatment to obtain the prepared bolt;

according to the design, the continuous production of the annealing process of the bolt hot forging blank is realized, the waste heat of annealing and cooling can be utilized in the annealing and heating stage, the continuous production of the bolt hot forging is realized, the bolt production efficiency and the automation degree are improved, the occupied space is reduced, and the efficiency is improved.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the equipment or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" 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" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.