Eccentric sleeve polishing device for shearing machine

Abstract

The invention discloses an eccentric sleeve polishing device for a plate shearing machine in the field of eccentric sleeve processing of a plate shearing machine, comprising a base, a first square groove and a third square groove are provided at the upper end of the base, a first guide groove is provided at the side end of the first square groove, a first threaded block is slidably arranged in the first guide groove, a first support plate is fixedly connected to the upper end of the first threaded block, a hydraulic cylinder is fixedly connected to the front end of the first support plate, a hydraulic rod is sleeved in the hydraulic cylinder, and a grinding block is fixedly connected to the front end surface of the hydraulic rod; the first threaded block is threadedly connected to a screw rod, a first bevel gear is fixedly connected to the side end of the screw rod, a second bevel gear is meshed with the first bevel gear, a first rotating shaft is fixedly connected to the front end of the second bevel gear, and a first disc is fixedly connected to the front end of the first rotating shaft. The invention has a simple structure and low manufacturing cost, and only simple operation is required to achieve the purpose of changing the size of the end face and adjusting the distance between the two clamps.

Description

Technical Field

[0001] The invention relates to the field of eccentric sleeve processing of shearing machines, in particular to an eccentric sleeve polishing device for shearing machines. Background Art

[0002] Shearing machine is a machine that shears plates by reciprocating linear motion of one blade relative to another blade. It uses the moving upper blade and the fixed lower blade, and adopts a reasonable blade gap to apply shear force to metal plates of various thicknesses, so that the plates are broken and separated according to the required size. Shearing machine is a kind of forging machine, and its main function is metal processing industry. Shearing machine is a kind of shearing equipment widely used in machining, which can shear steel plates of various thicknesses. Commonly used shearing machines are divided into three types: flat shearing, rolling shearing and vibration shearing. The products are widely used in aviation, light industry, metallurgy, chemical industry, construction, shipbuilding, automobile, electricity, electrical appliances, decoration and other industries to provide the required special machinery and complete sets of equipment. The eccentric sleeve is an internal part of the shearing machine. When installing the eccentric sleeve, the surface of the eccentric sleeve needs to be polished to meet a certain roughness.

[0003] However, when the traditional eccentric sleeve polishing device is grinding the outer cylindrical surface of the eccentric sleeve, it is unable to adjust the size of the fixture end face according to the size of the eccentric sleeve end face. Different fixtures need to be replaced when processing eccentric sleeves of different sizes. This is not only time-consuming and labor-intensive, but also increases the use cost and wastes resources. When the traditional eccentric sleeve polishing device is adjusting the processing length, it relies on moving the tailstock to adjust the distance between the fixtures. When moving the tailstock, it is necessary to loosen the fixing stud and then hold the eccentric sleeve for comparison, and try it out while moving, which increases the difficulty of length adjustment.

[0004] Therefore, those skilled in the art provide a polishing device for an eccentric sleeve of a shearing machine to solve the problems raised in the above background technology. Summary of the invention

[0005] The purpose of the present invention is to provide an eccentric sleeve polishing device for a plate shearing machine to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The eccentric sleeve polishing device of the shearing machine comprises a base, the upper end of the base is provided with a first square groove and a third square groove, the side end of the first square groove is provided with a first guide groove, a first threaded block is slidably arranged in the first guide groove, the upper end of the first threaded block is fixedly connected to a first support plate, the front end of the first support plate is fixedly connected to a hydraulic cylinder, a hydraulic rod is sleeved in the hydraulic cylinder, and a grinding block is fixedly connected to the front end surface of the hydraulic rod; the first threaded block is threadedly connected to a screw rod, the side end of the screw rod is fixedly connected to a first bevel gear, the first bevel gear is meshed with a second bevel gear, the front end of the second bevel gear is fixedly connected to a first rotating shaft, the front end of the first rotating shaft is fixedly connected to a first disc, and the first The front end of a disc is fixedly connected to a first handle; a second guide groove is opened at a side end of the third groove, and a third threaded block and a fourth threaded block are slidably arranged in the second guide groove, and the upper end of the third threaded block is fixedly connected to a second support plate, and the front end of the second support plate is rotatably connected to a clamping device, and the rear end of the second support plate is fixedly connected to a motor; the third threaded block and the fourth pattern block are threadedly connected to a bidirectional threaded rod, and the rear end of the bidirectional threaded rod is fixedly connected to a fifth bevel gear, and the fifth bevel gear is meshed with a fourth bevel gear, and the front end of the fourth bevel gear is fixedly connected to a third rotating shaft, and the front end of the third rotating shaft is fixedly connected to the second disc, and the front end of the second disc is fixedly connected to the second handle.

[0008] As a further solution of the present invention: the lower end of the base is fixedly connected with supporting legs, and the supporting legs are evenly distributed at the lower end of the bottom plate. By using this device, stable support can be achieved.

[0009] As a further scheme of the present invention: the clamping device includes a sleeve, a fixed shaft is fixedly arranged in the sleeve, the front end of the fixed shaft is fixedly connected to the first connecting block, the front end of the first connecting block is fixedly connected to the connecting shaft, the front end of the connecting shaft is fixedly connected to the clamping plate, the front end of the first connecting block is rotatably arranged with a second connecting block, a stepped groove is provided in the second connecting block, the front end of the second connecting block is fixedly connected to a fixing plate, the rear end of the fixing plate is fixedly connected to a disc-shaped tooth, the disc-shaped tooth is meshed with a third bevel gear, the upper end of the third bevel gear is provided with a hexagonal groove, and the lower end of the bevel gear is rotatably connected to the second rotating shaft; the front end of the fixing plate is fixedly connected to a disc-shaped thread, the disc-shaped thread is threadedly connected to the second thread block, and the upper end of the second thread block is fixedly connected to the telescopic plate; the front end of the sleeve is fixedly connected to a protective cover, the front end of the protective cover is provided with a square hole, and the side end of the square hole is provided with a second square groove, so that the size of the end face of the clamp can be changed by using this device.

[0010] As a further solution of the present invention: the second threaded block and the telescopic plate slide in the square hole and correspond to the square holes one by one. The second threaded block and the telescopic plate are evenly distributed at the front end of the disc-shaped thread. By using this device, stable clamping of the eccentric sleeve can be achieved.

[0011] As a further solution of the present invention: the second square grooves are symmetrically distributed on both sides of the square groove. By using this device, the telescopic plate can slide stably without deviation.

[0012] As a further solution of the present invention: the front end of the base is fixedly connected with a first fixing block, and the first fixing blocks are evenly distributed on the side end of the base, and the first rotating shaft passes through the first fixing block. By using this device, the first rotating shaft can be fixed.

[0013] As a further solution of the present invention: a second fixing block is fixedly connected to the rear end of the base side, and the third rotating shaft passes through the second fixing block. By using this device, the third rotating shaft can be fixed.

[0014] As a further solution of the present invention: the first square groove, the first threaded block, the first support plate, the screw rod, the first bevel gear, and the second bevel gear are symmetrically distributed at both ends of the base. By using this device, the eccentric sleeve can be polished, and the movement of the hydraulic rod can achieve the purpose of centering.

[0015] As a further solution of the present invention: the second guide grooves are symmetrically distributed on both sides of the third rectangular groove. By using this device, the third thread block and the fourth thread block can slide stably without deviation.

[0016] As a further solution of the present invention: the third threaded block, the fourth threaded block, the second support plate and the clamping device are symmetrically distributed at both ends of the third triangular groove, the thread directions of the third threaded block and the fourth threaded block are opposite, and the thread shapes of the third threaded block and the fourth threaded block are triangular. By using this device, the clamping device can be moved to the middle or to both sides at the same time, and it will self-lock when clamping the eccentric sleeve.

[0017] Beneficial Effects

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. By holding the hexagonal wrench against the hexagonal groove and turning the hexagonal wrench, the third bevel gear is rotated. As the third bevel gear rotates, the fixed plate is rotated under the action of the disc-shaped teeth. The rotation of the fixed plate causes the second threaded block threadedly connected to the front end of the fixed plate to slide. As the second threaded block moves in the square hole, the telescopic plate is driven to slide in the second square groove, thereby solving the problem that the end face size cannot be changed.

[0020] 2. Hold the eccentric sleeve close to the grinding block with your hand, start the hydraulic pump, and push the hydraulic rod forward under the action of the hydraulic cylinder. When the grinding block on the other side also touches the eccentric sleeve, turn off the hydraulic pump. At this time, turn the second handle. The rotation of the second handle drives the rotation of the third rotating shaft. The rotation of the third rotating shaft will cause the fourth bevel gear to rotate. The rotation of the fourth bevel gear and the fifth bevel gear meshing with it will also rotate. As the fifth bevel gear rotates, the third thread block and the fourth thread block will move in the third triangular groove. This solves the problem of inconvenience in adjusting the distance between the clamps.

[0021] 3. By turning on the motor, the motor drives the clamping device to rotate, and then the first handle is rotated. As the first handle rotates, the first rotating shaft rotates. The rotation of the first rotating shaft causes the first threaded block to slide in the first square groove. As the first threaded block slides, the grinding block moves on the outer cylindrical surface of the eccentric sleeve, thereby achieving the purpose of polishing the eccentric sleeve, greatly reducing the labor intensity of workers and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a schematic diagram of the overall structure of the present invention viewed from above;

[0024] Figure 3 It is a schematic diagram of the disassembled structure of the clamping device in the present invention;

[0025] Figure 4 It is a structural schematic diagram of the cross section of the clamping device in the present invention;

[0026] Figure 5 For the present invention Figure 4 Schematic diagram of the structure with part A enlarged.

[0027] In the figure: 1-base, 2-leg, 3-first square groove, 4-first guide groove, 5-first support plate, 6-first threaded block, 7-hydraulic cylinder, 8-hydraulic rod, 9-grinding block, 10-first bevel gear, 11-second bevel gear, 12-first rotating shaft, 13-first fixed block, 14-first disc, 15-first handle, 16-second support plate, 17-clamping device, 1701-sleeve, 1702-third bevel gear, 1703-fixed shaft, 1704-disc-shaped teeth, 1705-fixed plate, 1706-disc-shaped thread, 1707-first connecting block, 1708-telescopic Plate, 1709-second threaded block, 1710-protective cover, 1711-square hole, 1712-second square groove, 1713-hexagonal groove, 1714-second rotating shaft, 1715-step groove, 1716-clamp plate, 1717-connecting shaft, 1718-second connecting block, 18-third rectangular groove, 19-second guide groove, 20-third threaded block, 21-fourth threaded block, 22-second disc, 23-second handle, 24-fourth bevel gear, 25-fifth bevel gear, 26-third rotating shaft, 27-second fixed block, 28-screw, 29-motor, 30-bidirectional threaded rod. 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] See also Figures 1 to 5In the embodiment of the present invention, the eccentric sleeve polishing device of the shearing machine includes a base 1, a first square groove 3 and a third square groove 18 are opened on the upper end of the base 1, a first guide groove 4 is opened on the side end of the first square groove 3, a first threaded block 6 is slidably arranged in the first guide groove 4, a first support plate 5 is fixedly connected to the upper end of the first threaded block 6, a hydraulic cylinder 7 is fixedly connected to the front end of the first support plate 5, a hydraulic rod 8 is sleeved in the hydraulic cylinder 7, and a grinding block 9 is fixedly connected to the front end surface of the hydraulic rod 8; the first threaded block 6 is threadedly connected to a screw rod 28, a first bevel gear 10 is fixedly connected to the side end of the screw rod 28, the first bevel gear 10 is meshed with a second bevel gear 11, a first rotating shaft 12 is fixedly connected to the front end of the second bevel gear 11, a first rotating shaft 12 is fixedly connected to the front end of the first rotating shaft 12, and a first disc 14 is fixedly connected to the front end of the first disc 14. The front end is fixedly connected with the first handle 15; the side end of the third groove 18 is provided with a second guide groove 19, and the third threaded block 20 and the fourth threaded block 21 are slidably arranged in the second guide groove 19, the upper end of the third threaded block 20 is fixedly connected with the second support plate 16, the front end of the second support plate 16 is rotatably connected with the clamping device 17, and the rear end of the second support plate 16 is fixedly connected with the motor 29; the third threaded block 20 and the fourth pattern block are threadedly connected with the bidirectional threaded rod 30, the rear end of the bidirectional threaded rod 30 is fixedly connected with the fifth bevel gear 25, the fifth bevel gear 25 is meshed with the fourth bevel gear 24, the front end of the fourth bevel gear 24 is fixedly connected with the third rotating shaft 26, the front end of the third rotating shaft 26 is fixedly connected with the second disc 22, and the front end of the second disc 22 is fixedly connected with the second handle 23.

[0030] Among them, the lower end of the base 1 is fixedly connected with the support legs 2, and the support legs 2 are evenly distributed at the lower end of the bottom plate. By using this device, stable support can be achieved; the clamping device 17 includes a sleeve 1701, a fixed shaft 1703 is fixedly arranged in the sleeve 1701, a first connecting block 1707 is fixedly connected to the front end of the fixed shaft 1703, a connecting shaft 1717 is fixedly connected to the front end of the first connecting block 1707, a clamping plate 1716 is fixedly connected to the front end of the connecting shaft 1717, a second connecting block 1718 is rotatably arranged at the front end of the first connecting block 1707, a stepped groove 1715 is opened in the second connecting block 1718, a fixed plate 1705 is fixedly connected to the front end of the second connecting block 1718, and the fixed plate 1705 The rear end is fixedly connected with a disc-shaped tooth 1704, the disc-shaped tooth 1704 is meshed with the third bevel gear 1702, the upper end of the third bevel gear 1702 is provided with a hexagonal groove 1713, and the lower end of the bevel gear is rotatably connected with a second rotating shaft 1714; the front end of the fixed plate 1705 is fixedly connected with a disc-shaped thread 1706, the disc-shaped thread 1706 is threadedly connected with a second thread block 1709, and the upper end of the second thread block 1709 is fixedly connected with a telescopic plate 1708; the front end of the sleeve 1701 is fixedly connected with a protective cover 1710, the front end of the protective cover 1710 is provided with a square hole 1711, and the side end of the square hole 1711 is provided with a second square groove 1712. By using this device, the size of the end face of the clamp can be changed.

[0031] The second threaded block 1709 and the telescopic plate 1708 slide in the square hole 1711 and correspond to the square hole 1711 one by one. The second threaded block 1709 and the telescopic plate 1708 are evenly distributed at the front end of the disc-shaped thread 1706. By using this device, the eccentric sleeve can be stably clamped; the second square groove 1712 is symmetrically distributed on both sides of the square groove. By using this device, the telescopic plate 1708 can slide stably without deviation; the front end of the base 1 side is fixedly connected with the first fixed block 13, and the first fixed blocks 13 are evenly distributed on the side end of the base 1, and the first rotating shaft 12 passes through the first fixed block 13. By using this device, the first rotating shaft 12 can be fixed; the rear end of the base 1 side is fixedly connected with the second fixed block 27, and the third rotating shaft 26 passes through the second fixed block 27. By using this device, the third rotating shaft 26 can be fixed; the first square The shaped groove 3, the first threaded block 6, the first support plate 5, the screw 28, the first bevel gear 10, and the second bevel gear 11 are symmetrically distributed at both ends of the base 1. By using this device, the eccentric sleeve can be polished, and the movement of the hydraulic rod 8 can achieve the purpose of centering; the second guide groove 19 is symmetrically distributed on both sides of the third shaped groove 18. By using this device, the third threaded block 20 and the fourth threaded block 21 can slide stably without deviation; the third threaded block 20, the fourth threaded block 21, the second support plate 16 and the clamping device 17 are symmetrically distributed at both ends of the third shaped groove 18, the third threaded block 20 and the fourth threaded block 21 have opposite thread directions, and the thread shape of the third threaded block 20 and the fourth threaded block 21 is triangular. By using this device, the clamping device 17 can be moved to the middle or to both sides at the same time, and it will self-lock when clamping the eccentric sleeve.

[0032] The working principle of the present invention is:

[0033] When using the present invention, the device is placed where it is needed. When adjusting the size of the end face of the clamp, the hexagonal wrench is held by hand against the hexagonal groove 1713 and rotated, thereby causing the third bevel gear 1702 to rotate. As the third bevel gear 1702 rotates, the fixed plate 1705 rotates under the action of the disc-shaped teeth 1704. The rotation of the fixed plate 1705 causes the second threaded block 1709 threadedly connected to the front end of the fixed plate 1705 to slide. As the second threaded block 1709 moves in the square hole 1711, it drives the telescopic plate 1708 to slide in the second square groove 1712. As the telescopic plate 1708 continues to extend outward, the size of the end face of the clamp is adjusted.

[0034] When adjusting the length between the clamps according to the length of the eccentric sleeve, first hold the eccentric sleeve with your hand against the grinding block 9, start the hydraulic pump, and push the hydraulic rod 8 forward under the action of the hydraulic cylinder 7. When the grinding block 9 on the other side also touches the eccentric sleeve, turn off the hydraulic pump, and then turn the second handle 23. The rotation of the second handle 23 drives the rotation of the third rotating shaft 26. The rotation of the third rotating shaft 26 will cause the fourth bevel gear 24 to rotate. The rotation of the fourth bevel gear 24 and the fifth bevel gear 25 meshing therewith will also rotate. As the fifth bevel gear 25 rotates, the third threaded block 20 and the fourth threaded block 21 will move in the third triangular groove 18, thereby achieving the purpose of clamping the eccentric sleeve.

[0035] When the eccentric sleeve is being polished, the motor 29 is turned on, the motor 29 drives the clamping device 17 to rotate, and then the first handle 15 is rotated. As the first handle 15 rotates, the first rotating shaft 12 is rotated. When the first rotating shaft 12 rotates, the second bevel gear 11 drives the first bevel gear 10 to rotate. As the first bevel gear 10 rotates, the first threaded block 6 slides in the first square groove 3. The sliding of the first threaded block 6 in the first square groove 3 causes the polishing block 9 to polish the outer cylindrical surface of the eccentric sleeve. The present invention has a simple structure and a low manufacturing cost. Only simple operations are required to change the size of the end face and adjust the distance between the two clamps, which greatly reduces the labor intensity of workers and improves work efficiency.

[0036] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A polishing device for an eccentric sleeve of a plate shearing machine, comprising a base (1), characterized in that: The upper end of the base (1) is provided with a first square groove (3) and a third square groove (18); the side end of the first square groove (3) is provided with a first guide groove (4); a first threaded block (6) is slidably arranged in the first guide groove (4); the upper end of the first threaded block (6) is fixedly connected to a first support plate (5); the front end of the first support plate (5) is fixedly connected to a hydraulic cylinder (7); a hydraulic rod (8) is sleeved in the hydraulic cylinder (7); a grinding block (9) is fixedly connected to the front end surface of the hydraulic rod (8); the first threaded block (6) is threadedly connected to a screw rod (28); the side end of the screw rod (28) is fixedly connected to a first bevel gear (10); the first bevel gear (10) is meshed with a second bevel gear (11); the second bevel gear (11) is meshed with a second bevel gear (12); the second bevel gear (12) is meshed with a second bevel gear (13); the first bevel gear (10) is meshed with a second bevel gear (14); the second bevel gear (11) is meshed with a second bevel gear (15); the first bevel gear (10) is meshed with a second bevel gear (16); the first bevel gear (10) is meshed with a second bevel gear (11); the second bevel gear (11) is meshed with a second bevel gear (13); the first bevel gear (10) is meshed with a second bevel gear (15); the first bevel gear (10) is meshed with a second bevel gear (16); the first bevel gear (10) is meshed with a second bevel gear (11); the first bevel gear (11) is meshed with a second bevel gear (13); the first bevel gear (10) is meshed with a second bevel gear (13); the first bevel gear (10) is meshed with a second bevel gear (13); the The front end of the wheel (11) is fixedly connected to a first rotating shaft (12), the front end of the first rotating shaft (12) is fixedly connected to a first disc (14), and the front end of the first disc (14) is fixedly connected to a first handle (15); a second guide groove (19) is provided at a side end of the third groove (18), a third threaded block (20) and a fourth threaded block (21) are slidably arranged in the second guide groove (19), the upper end of the third threaded block (20) is fixedly connected to a second supporting plate (16), the front end of the second supporting plate (16) is rotatably connected to a clamping device (17), and the rear end of the second supporting plate (16) is fixedly connected to a motor (29); the third threaded block (20) and the fourth threaded block are threadedly connected to a bidirectional threaded rod (30), The rear end of the bidirectional threaded rod (30) is fixedly connected to a fifth bevel gear (25), the fifth bevel gear (25) is meshed with a fourth bevel gear (24), the front end of the fourth bevel gear (24) is fixedly connected to a third rotating shaft (26), the front end of the third rotating shaft (26) is fixedly connected to a second disc (22), the front end of the second disc (22) is fixedly connected to a second handle (23); the lower end of the base (1) is fixedly connected to a support leg (2), the support leg (2) is evenly distributed at the lower end of the bottom plate; the clamping device (17) comprises a sleeve (1701), a fixed shaft (1703) is fixedly arranged inside the sleeve (1701), the front end of the fixed shaft (1703) is fixedly connected to a first connecting block (1707), the The front end of the first connecting block (1707) is fixedly connected to a connecting shaft (1717), the front end of the connecting shaft (1717) is fixedly connected to a clamping plate (1716), the front end of the first connecting block (1707) is rotatably provided with a second connecting block (1718), a stepped groove (1715) is provided in the second connecting block (1718), the front end of the second connecting block (1718) is fixedly connected to a fixing plate (1705), the rear end of the fixing plate (1705) is fixedly connected to a disc-shaped tooth (1704), the disc-shaped tooth (1704) is meshed with a third bevel gear (1702), the upper end of the third bevel gear (1702) is provided with a hexagonal groove (1713), and the lower end of the bevel gear is rotatably connected to a second rotating shaft (1714);The front end of the fixing plate (1705) is fixedly connected with a disc-shaped thread (1706), the disc-shaped thread (1706) is threadedly connected with a second thread block (1709), and the upper end of the second thread block (1709) is fixedly connected with a telescopic plate (1708); the front end of the sleeve (1701) is fixedly connected with a protective cover (1710), the front end of the protective cover (1710) is provided with a square hole (1711), and the side end of the square hole (1711) is provided with a second square groove (1712). ; 2. The eccentric sleeve polishing device for shearing machine according to claim 1 is characterized in that: The second thread block (1709) and the telescopic plate (1708) slide in the square hole (1711) and correspond one-to-one with the square hole (1711). The second thread block (1709) and the telescopic plate (1708) are evenly distributed at the front end of the disc-shaped thread (1706).

3. The eccentric sleeve polishing device for shearing machine according to claim 1 is characterized in that: The second square grooves (1712) are symmetrically distributed on both sides of the square groove.

4. The eccentric sleeve polishing device for shearing machine according to claim 1, characterized in that: A first fixing block (13) is fixedly connected to the front end of the base (1), and the first fixing blocks (13) are evenly distributed on the side end of the base (1), and the first rotating shaft (12) passes through the first fixing block (13).

5. The eccentric sleeve polishing device for shearing machine according to claim 1, characterized in that: A second fixing block (27) is fixedly connected to the rear end of the base (1), and the third rotating shaft (26) passes through the second fixing block (27).

6. The eccentric sleeve polishing device for shearing machine according to claim 1, characterized in that: The first square groove (3), the first threaded block (6), the first support plate (5), the screw rod (28), the first bevel gear (10), and the second bevel gear (11) are symmetrically distributed at two ends of the base (1).

7. The eccentric sleeve polishing device for shearing machine according to claim 1, characterized in that: The second guide grooves (19) are symmetrically distributed on both sides of the third rectangular groove (18).

8. The eccentric sleeve polishing device for shearing machine according to claim 1, characterized in that: The third thread block (20), the fourth thread block (21), the second support plate (16) and the clamping device (17) are symmetrically distributed at two ends of the third triangular groove (18); the thread directions of the third thread block (20) and the fourth thread block (21) are opposite, and the thread shapes of the third thread block (20) and the fourth thread block (21) are triangular.

Images