Aluminum piston integral forming machining process

Abstract

The invention discloses an aluminum piston integral forming machining process, and relates to the technical field of aluminum piston integral forming, and the aluminum piston integral forming machining process comprises the following steps of aluminum bar cutting, flame heating, primary forming, secondary stamping and high-temperature and low-temperature switching heating. The non-electric clamping and fixing in the piston punch forming process can be completed by arranging the clamping mechanism on the first transmission mechanism and the limiting and carrying mechanism on the second transmission mechanism, meanwhile, the piston in the clamping process can be limited and moved, and the overall stability during secondary punching in the piston integrated forming process is improved. Mechanical carrying of the aluminum column in the stamping table in the piston integrated forming process is achieved, and the overall operation safety is improved while the piston stamping forming efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of integrated aluminum piston molding, and in particular to an integrated aluminum piston molding processing technology. Background Art

[0002] As the requirements of automobiles for engine power, economy, environmental protection and reliability are becoming more and more stringent, pistons have developed into high-tech products that integrate light-weight and high-strength new materials, special-shaped outer cylindrical composite surfaces, special-shaped pin holes and other new technologies to ensure the heat resistance, wear resistance, stable guidance and good sealing function of the piston, reduce the friction power loss of the engine, and reduce fuel consumption, noise and emissions;

[0003] As a typical key automotive component, the piston has strong process characteristics in cutting and processing. The domestic piston manufacturing industry usually consists of a machining production line composed of general-purpose machine tools and special equipment that combines the process characteristics of pistons. Therefore, special equipment becomes the key equipment for piston cutting and processing. Its function and precision will directly affect the quality indicators of the key characteristics of the final product.

[0004] According to the patent document with publication number CN103978057A, the forming of the aluminum piston is carried out in the mold, and considering the stability of the piston during the forming process, midway cooling and secondary stamping operations are also performed to improve the overall quality of the piston. However, for the subsequent operation and movement of the piston, the movement operation involved in the production line cannot guarantee the stability of the formed piston, which is easy to cause the piston to deform during the secondary stamping process, resulting in an increase in the scrap rate of the one-piece piston.

[0005] Therefore, we propose an integrated aluminum piston molding process. Summary of the invention

[0006] The purpose of the present invention is to provide an integrated aluminum piston forming process to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: an integrated aluminum piston forming process, comprising the following steps:

[0008] Step 1: Cut the aluminum rod using a cutting assembly according to the piston forming length;

[0009] Step 2: Flame heating: use a flame at 800°C to heat the cut aluminum block, and move the heated aluminum block to the top of the placement table;

[0010] Step 3: One-time forming: use the transmission mechanism 1 to cooperate with the lifting mechanism to clamp the heated aluminum block and move it to the top of the mold cavity 1. Use the upper punch 1 to apply 2000t pressure to extrude the aluminum block to complete the piston forming;

[0011] Step 4: Secondary stamping: After the stamping is completed, the piston is ejected from the die cavity 1, and at the same time, the limit conveying mechanism on the side of the upper slide of the transmission mechanism 2 carries the piston to the slide. At the same time, the transmission mechanism 1 drives the new aluminum block to the die cavity 1. As the aluminum block is formed, the piston cooled in the cooling chamber is moved to the die cavity 2 again through the limit conveying mechanism, and the transmission mechanism 1 drives the newly formed piston to the slide. Finally, the limit conveying mechanism on the slide 2 clamps the piston after the secondary stamping and discharges it from the stamping table;

[0012] Step 5: High-temperature and low-temperature switching heating, use a heating furnace to bake the aluminum piston twice, the high-temperature baking temperature is controlled at 250°C, the low-temperature baking temperature is controlled at 120°C, and the single baking time is controlled at 1-1.5h.

[0013] Among them, the one-piece forming processing technology of the aluminum piston is realized by relying on a processing device, specifically including a stamping table, in which an upper punching table 1 and an upper punching table 2 are installed, a lower die table is installed on the inner wall of the bottom of the stamping table, and a die cavity 1 and a die cavity 2 are opened on the top of the lower die table, a cooling cavity is opened on the top of the lower die table and located between the die cavity 1 and the die cavity 2, a slide is slidably connected in the cooling cavity, and a liquid inlet box is fixed to the bottom of the lower die table by bolts.

[0014] Furthermore, a transmission mechanism 1 is fixed on the stamping table by bolts, a clamping mechanism is installed on the transmission mechanism 1, a placing table is installed at the bottom of the transmission mechanism 1, and a lifting mechanism is installed at the bottom of the placing table.

[0015] Furthermore, a transmission mechanism 2 is fixed to the inner wall of the stamping table by bolts, and a slide 1 and a slide 2 are evenly slidably connected on the transmission mechanism 2, and a limited transport mechanism is installed on the slide 1 and the slide 2.

[0016] Furthermore, the limiting transport mechanism includes a cylinder column, limiting cylinder 1 and limiting cylinder 2, the slide 1 and the slide 2 are slidably connected to the top of the cylinder column, the top inner wall of the cylinder column is fixed to the limiting cylinder 1 by bolts, and the bottom inner wall of the cylinder column is fixed to the limiting cylinder 2 by bolts.

[0017] Furthermore, the limiting transport mechanism also includes a tooth column and an abutment column. The outer wall of the cylinder column is symmetrically fixed with the tooth column by spot welding. The cylinder column is slidably connected with the abutment column inside the limiting cylinder 2, and the protrusion on the outer wall of the abutment column abuts with the limiting cylinder 2. One end of the abutment column passes through the cylinder column and is fixed with a lock by spot welding.

[0018] Furthermore, a placement plate is slidably connected to the two gear columns, a tooth plate is symmetrically slidably connected in the groove on the top of the placement plate, a transmission box is symmetrically fixed on both sides of the top of the placement plate, the gear in the transmission box is meshed and connected to the outer wall of the gear column, and the other side of the gear is correspondingly meshed and connected to the tooth plate, and an arc clamp is symmetrically slidably connected to the bottom of the placement plate, and one side of the top of the arc clamp passes through the groove and is fixed to the tooth plate accordingly.

[0019] Furthermore, a positioning block is fixedly connected to the bottom of the placement plate and located on the opposite side of the arc clamp, a locking block is fixed to the top of the placement plate by bolts, and the locking block and the locking head are arranged correspondingly, an electric push rod is fixed to the top of slide one and slide two by bolts, and one end of the electric push rod is fixed to the outer wall of the column.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. In the present invention, by installing relevant conveying mechanisms on the stamping table, the clamping mechanism and the limit conveying mechanism are used to position and move the placed aluminum column and the stamped piston semi-finished product. Compared with manual clamping and placement, the moving efficiency is high and the operation safety performance is improved. At the same time, it is convenient to improve the aluminum piston forming rate. The upper punching platform 1 and the upper punching platform 2 are set on the entire stamping table, and a cooling chamber is installed between the two. The circuit design is carried out through the piston integrated forming process, which improves the overall stamping forming efficiency of the piston;

[0022] 2. In the present invention, an electric push rod is used to move the position of the cylinder on the slide, so that when the arc clamp at the bottom of the placement plate reaches the outer wall of the piston, the position of the cylinder itself is adjusted to automatically control the rotation of the gear in the transmission box, and drive the arc clamp connected to the gear plate to move. At the same time, when the cylinder rises, the arc clamp automatically fits the outer wall of the piston. At the same time, the positioning block set at the bottom of the placement plate squeezes the piston groove to avoid deflection of the piston during clamping. Finally, after the arc clamp completely clamps the piston, the slide moves to drive the entire piston to leave the stamping table. The limiting and transporting mechanism as a whole adjusts the height of the cylinder through the electric push rod, thereby completing the non-electrical clamping and fixing of the piston. At the same time, the piston can be limited during the clamping process, thereby improving the overall stability of the piston during the secondary stamping in the one-piece forming process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a process flow chart of the integrated forming process of the aluminum piston of the present invention;

[0024] Figure 2 It is an overall schematic diagram of the aluminum piston integrated molding processing equipment of the present invention;

[0025] Figure 3 It is a schematic diagram of the installation of the transmission mechanism 1 and the transmission mechanism 2 on the top of the lower die table of the present invention;

[0026] Figure 4 This is a schematic diagram of the installation structure of the liquid inlet box at the bottom of the lower die table of the present invention;

[0027] Figure 5 It is a schematic diagram of the installation structure of the second upper slide and the second slide of the transmission mechanism of the present invention;

[0028] Figure 6 It is a schematic diagram of the overall structure of the second upper limit transport mechanism of the slide table of the present invention;

[0029] Figure 7 It is a schematic diagram of the installation structure of the first limiting cylinder and the second limiting cylinder in the cylinder column of the present invention;

[0030] Figure 8 This is a schematic diagram of the structure in which the tooth plate movably drives the arc clamp to complete the clamping of the piston.

[0031] In the figure: 1, punching table; 2, upper punching table 1; 3, upper punching table 2; 4, placing table; 5, lifting mechanism; 6, transmission mechanism 1; 7, clamping mechanism; 8, transmission mechanism 2; 9, slide 1; 10, slide 2; 11, lower die table; 12, mold cavity 1; 13, cooling cavity; 14, slide; 15, mold cavity 2; 16, liquid inlet box; 17, limit transport mechanism; 171, cylinder column; 172, limit cylinder 1; 173, limit cylinder 2; 174, tooth column; 175, abutment column; 176, lock; 18, electric push rod; 19, placing plate; 20, locking block; 21, tooth plate; 22, arc clamp; 23, transmission box; 24, positioning block. DETAILED DESCRIPTION

[0032] 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.

[0033] See also Figure 1-8 , the present invention provides a technical solution:

[0034] Embodiment 1: To speed up the piston stamping forming rate and avoid the time-consuming and labor-intensive problem of manually clamping the upper and lower dies of the piston, Figure 2 As shown, by installing the transmission mechanism 1 6 and the transmission mechanism 2 8 in the stamping table 1, the piston is automatically clamped and displaced during the stamping process, and multiple forming stamping and cooling of the piston are completed during the displacement process;

[0035] according to Figure 1In the piston integral stamping forming step shown, the aluminum column heated by 800°C high temperature jet flame is placed on the placement table 4, and the heated aluminum column is moved to the mold cavity 12 on the lower mold table 11 in coordination with the activity of the lifting mechanism 5 and the vertical clamping of the clamping mechanism 7. Compared with the limit transfer mechanism 17 installed on the transmission mechanism 2 8, the entire clamping mechanism 7 does not need to pay attention to the position and direction of the aluminum column during the clamping process. It only needs to set a conventional clamp to clamp the outer wall of the aluminum column, and move the aluminum column to the mold cavity 12 under the operation of the transmission mechanism 1 6;

[0036] As for the stamping work of the entire aluminum column, an upper punch platform 2 and an upper punch platform 2 3 are installed on the stamping table 1, and a mold cavity 12 and a mold cavity 2 15 are respectively opened on the surface of the lower mold platform 11 corresponding to the upper punch platform 1 2 and the upper punch platform 2 3. According to the piston forming appearance, an upper punch head is installed on the stamping side of the entire upper punch platform 1 2 and the upper punch platform 2 3 for single-sided groove stamping of the aluminum column. At the same time, the entire mold cavity 12 and the mold cavity 2 15 are installed with a telescopic pad. When the punch head extrude the aluminum column in the mold cavity 1 12 or the mold cavity 2 15, the semi-finished piston is automatically ejected after the stamping is completed. At the same time, the pad radius is smaller than the piston, which is convenient for the subsequent limiting and handling mechanism 17 to grasp and transport the semi-finished piston.

[0037] The surface temperature of the semi-finished piston after 2000 tons of stamping is relatively high. During the stamping process, the lubricating oil is cooled. At high temperatures, the position of the die cavity 12 is prone to ignition. Subsequently, the semi-finished piston needs to be cooled by water after the first stamping. A cooling cavity 13 is provided on the lower die table 11 and between the die cavity 12 and the die cavity 2 15.

[0038] like Figure 4 As shown, a liquid inlet box 16 is installed at the bottom of the entire cooling chamber 13 to continuously transport cooling water to the cooling chamber 13. After the punch head at the bottom of the upper punching platform 12 descends, the semi-finished piston placed on the top of the slide 14 will also be driven to descend together, so that the semi-finished piston on the top of the slide 14 is pressed down into the water in the cooling chamber 13 to complete the rapid cooling of the semi-finished piston. Compared with unloading from the surface of the punching platform 1 and then cooling, the cooling rate of the semi-finished piston is reduced;

[0039] Along with the water cooling work of the piston semi-finished product, in order to further complete the stable forming of the piston groove, another stamping is required. For this purpose, the semi-cooled piston stamping work is completed in the mold cavity 15 under the operation of the upper punching platform 2 3. As for the limiting movement of the entire piston semi-finished product, the transmission mechanism 2 8 and the upper limiting conveying mechanism 17 are required to prevent the steering deviation of the piston semi-finished product caused during the movement, which leads to the failure of the piston stamping during the secondary stamping. The piston after the secondary stamping is moved out of the stamping platform 1 through the limiting conveying mechanism 17, and then moved to the baking oven for high and low temperature switching heating, high temperature piston strengthening and low temperature piston stabilization, and finally the piston surface blade cutting and drilling work are performed on the lathe to complete the entire piston molding.

[0040] Example 2: Figure 5 As shown, slide 1 9 and slide 2 10 are installed on transmission mechanism 2 8, slide 1 9 and the clamping mechanism on transmission mechanism 1 6 are used to move the pistons on the surfaces of cavity 1 12 and cavity 2 15, and the upper limit conveying mechanism 17 on slide 2 10 is responsible for clamping and discharging the pistons formed by secondary stamping on die table 2, and the piston stamping process of the top of lower die table 11 is moved through the cooperation and sliding of slide 1 9 and slide 2 10, thereby improving the entire piston stamping continuity and stamping rate;

[0041] For the entire limiting transport mechanism 17 Figure 6 As shown, an electric push rod 18 is symmetrically fixed on the slide 10 by bolts, and the electric push rod 18 is connected to the limit conveying mechanism 17, wherein the cylinder 171 of the main body is slidably connected to the slide 10, and slides up and down on the surface of the slide 10 through the electric push rod 18, and a placement plate 19 is slidably connected to the bottom of the tooth column 174 symmetrically connected to the outer wall of the cylinder 171, and a transmission box 23 is symmetrically arranged on the placement plate 19, and a gear set is installed in the transmission box 23;

[0042] The gear on the outer side of the gear set is meshed and connected with the toothed plate 21 on the placement plate 19, and the gear on the inner side of the transmission box 23 is meshed and connected with the toothed column 174. Therefore, the toothed column 174 slides on the placement plate 19 to realize the sliding of the toothed plate 21 on the top of the placement plate 19. At the same time, the arc clamps 22 symmetrically arranged at the bottom of the placement plate 19 are correspondingly connected to the toothed plate 21. With the sliding of the toothed plate 21, the two arc clamps 22 at the bottom can clamp the outer wall of the piston. At the same time, balls are evenly embedded at the bottom of the arc clamps 22, which is convenient for the subsequent pressing of the entire arc clamp 22 onto the lower die table 11 and can also perform a smooth moving operation.

[0043] The entire cylinder 171 is also fixedly connected with a limiting cylinder 172 and a limiting cylinder 2 173. Figure 7As shown, the abutment column 175 slidably connected in the cylinder 171 is hung on the limiting cylinder 173 through the protrusion on the outer wall, and the abutment column 175 is fixedly connected to the outer wall of the cylinder 171 with a lock 176, as shown in FIG. Figure 8 As shown, in normal state, the lock head 176 is engaged with the groove of the lock block 20 fixed on the top of the placement plate 19, and the electric push rod 18 moves to control the entire arc clamp 22 to move on the top of the lower die table 11;

[0044] When the arc clamp 22 moves to the outer side of the piston where the stamping of the surface of the mold cavity 12 is completed, the arc clamp 22 presses down to push the entire placement plate 19 to slide upward on the surface of the tooth column 174. During the sliding process, the gear inside the transmission box 23 contacts the tooth column 174, and during the rotation process, the distance between the arc clamps 22 on both sides of the bottom of the placement plate 19 is increased. At the same time, the lock head 176 in the lock block 20 starts to push the abutment column 175 to slide in the cylinder column 171 as the placement plate 19 rises. The outer wall protrusion of the abutment column 175 starts to slide upward in the cylinder column 171, and after the protrusion on the abutment column 175 contacts the limit cylinder 172, it is limited by the cross section of the limit cylinder 172 and drives the entire abutment column 175 to rotate at an angle.

[0045] Then, when the electric push rod 18 drives the entire cylinder 171 to rise, the placement plate 19 remains stationary at this time, and drives the gear in the transmission box 23 to rotate during the sliding process of the tooth column 174, thereby driving the arc clamp 22 connected to the tooth plate 21 to move towards each other, thereby clamping the mold cavity 12, the mold cavity 2 15 and the piston placed on the top of the slide 14, and at the same time, the positioning block 24 installed at the bottom of the placement plate 19 abuts against the piston stamping port to avoid rotation during the piston clamping and moving process, resulting in subsequent stamping and piston forming failure;

[0046] After the entire arc clamp 22 completes clamping the outer wall of the piston, the electric push rod 18 drives the entire cylinder 171 to rise, and the tooth column 174 cannot slide normally on the placement plate 19. At this time, the stable bottom of the placement plate 19 moves with the piston, and after the piston at the bottom of the electric push rod 18 contacts the table, the arc clamp 22 automatically unfolds, and at the same time, the lock head 176 begins to move into the lock block 20, and rotates under the limit of the limit cylinder 172. After the lock head 176 rotates, the lock block 20 is re-locked. At this time, the piston has been detached from the arc clamp 22, completing the limit movement of the entire piston, ensuring the stability of the placement position of the piston during stamping.

[0047] In the present invention, according to the piston forming length, the aluminum rod is cut by using a cutting assembly, the aluminum column is heated by spraying flames through a heating mechanism, the cut aluminum block is heated by a flame at a temperature of 800°C, and the heated aluminum block is moved to the top of a placing table 4, the transmission mechanism 6 is used to cooperate with the lifting mechanism 5 to clamp the heated aluminum block and move it to the top of a mold cavity 12, and the upper punching table 2 is used to apply a pressure of 2000t to extrude the aluminum block to complete the piston forming;

[0048] After the stamping is completed, the mold cavity 12 ejects the piston. At the same time, the transmission mechanism 2 8 and the side limiting and transporting mechanism 17 on the slide 9 drive the cylinder 171 to move through the electric push rod 18, so that the arc clamp 22 carries the piston to the slide 14. At the same time, the transmission mechanism 16 drives the new aluminum block to the mold cavity 12. As the aluminum block is formed, the piston cooled in the cooling chamber 13 is moved to the mold cavity 2 15 again through the limiting and transporting mechanism 17, and the transmission mechanism 16 drives the newly formed piston to the slide 14. Finally, the limiting and transporting mechanism 17 on the slide 2 10 clamps the piston after the secondary stamping and discharges it from the stamping table 1, so that the piston is integrally formed on the stamping table 1.

[0049] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. The one-piece forming process of aluminum piston is characterized by: The following steps are involved: Step 1: Cut the aluminum rod using a cutting assembly according to the piston forming length; Step 2: flame heating, using a flame at a temperature of 800° C. to heat the cut aluminum block, and moving the heated aluminum block to the top of the placement table (4); Step 3: One-step forming: using the transmission mechanism 1 (6) to cooperate with the lifting mechanism (5) to clamp the heated aluminum block and move it to the top of the mold cavity 1 (12), and using the upper punch 1 (2) to apply a pressure of 2000 tons to extrude the aluminum block to complete the piston forming; Step 4: Secondary stamping. After the stamping is completed, the piston is ejected from the die cavity 1 (12). At the same time, the transmission mechanism 2 (8) upper slide 1 (9) side limit transport mechanism (17) carries the piston to the slide (14). At the same time, the transmission mechanism 1 (6) drives the new aluminum block to the die cavity 1 (12). As the aluminum block is formed, the piston cooled in the cooling chamber (13) is moved to the die cavity 2 (15) again through the limit transport mechanism (17). The transmission mechanism 1 (6) drives the newly formed piston to the slide (14). Finally, the limit transport mechanism (17) of the slide 2 (10) clamps the piston after the secondary stamping and discharges it from the stamping table (1). Step 5: High-temperature and low-temperature switching heating, use a heating furnace to bake the aluminum piston twice, the high-temperature baking temperature is controlled at 250°C, the low-temperature baking temperature is controlled at 120°C, and the single baking time is controlled at 1-1.5h.

2. The aluminum piston integral molding process according to claim 1, characterized in that: The aluminum piston integral molding processing technology is implemented by relying on a processing device, and specifically comprises a punching table (1), wherein an upper punching table (2) and an upper punching table (3) are installed in the punching table (1), a lower die table (11) is installed on the inner wall of the bottom of the punching table (1), a die cavity (12) and a die cavity (15) are opened on the top of the lower die table (11), a cooling cavity (13) is opened on the top of the lower die table (11) and located between the die cavity (12) and the die cavity (15), a slide (14) is slidably connected in the cooling cavity (13), and a liquid inlet box (16) is fixed to the bottom of the lower die table (11) by bolts.

3. The aluminum piston integral molding process according to claim 2, characterized in that: A transmission mechanism (6) is fixed to the punching table (1) by bolts, a material clamping mechanism (7) is installed on the transmission mechanism (6), a placement table (4) is installed at the bottom of the transmission mechanism (6), and a lifting mechanism (5) is installed at the bottom of the placement table (4).

4. The aluminum piston integral molding process according to claim 3 is characterized in that: The inner wall of the punching table (1) is fixed with a transmission mechanism 2 (8) by bolts, and the transmission mechanism 2 (8) is evenly slidably connected with a slide table 1 (9) and a slide table 2 (10), and a limited position transport mechanism (17) is installed on the slide table 1 (9) and the slide table 2 (10).

5. The aluminum piston integral molding process according to claim 4, characterized in that: The position-limiting transport mechanism (17) comprises a cylinder column (171), a position-limiting cylinder 1 (172) and a position-limiting cylinder 2 (173); the top of the slide 1 (9) and the slide 2 (10) are slidably connected with the cylinder column (171); the top inner wall of the cylinder column (171) is fixed to the position-limiting cylinder 1 (172) by bolts; the bottom inner wall of the cylinder column (171) is fixed to the position-limiting cylinder 2 (173) by bolts.

6. The aluminum piston integral molding process according to claim 5, characterized in that: The position limiting transport mechanism (17) further comprises a tooth column (174) and an abutment column (175); the tooth column (174) is symmetrically fixed to the outer wall of the cylinder column (171) by spot welding; the cylinder column (171) is slidably connected to the abutment column (175) inside the second position limiting cylinder (173); a protrusion on the outer wall of the abutment column (175) abuts against the second position limiting cylinder (173); one end of the abutment column (175) passes through the cylinder column (171) and is fixed with a lock head (176) by spot welding.

7. The aluminum piston integral molding process according to claim 6, characterized in that: A placement plate (19) is slidably mounted on the two tooth columns (174), a tooth plate (21) is symmetrically slidably connected in a groove at the top of the placement plate (19), a transmission box (23) is symmetrically fixed on both sides of the top of the placement plate (19), an internal gear of the transmission box (23) is meshingly connected to the outer wall of the tooth column (174), and the other side of the gear is correspondingly meshingly connected to the tooth plate (21), and an arc clamp (22) is symmetrically slidably connected to the bottom of the placement plate (19), and one side of the top of the arc clamp (22) passes through the groove and is correspondingly fixed to the tooth plate (21).

8. The aluminum piston integral molding process according to claim 7, characterized in that: A positioning block (24) is fixedly connected to the bottom of the placement plate (19) and located on the opposite side of the arc clamp (22); a locking block (20) is fixed to the top of the placement plate (19) by bolts, and the locking block (20) and the locking head (176) are arranged correspondingly; an electric push rod (18) is fixed to the top of the slide table (9) and the slide table (10) by bolts, and one end of the electric push rod (18) is fixed to the outer wall of the column (171).

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