Welding auxiliary device and shield body assembling and welding auxiliary clamp of shield tunneling machine

Abstract

The welding auxiliary device comprises an adjusting screw rod, a first mounting plate and a second mounting plate, the bottom of the first mounting plate is connected with a first to-be-welded assembly, a first through hole is formed in the first mounting plate, the bottom of the second mounting plate is connected with a second to-be-welded assembly, and a second through hole is formed in the second mounting plate. A second through hole corresponding to the first through hole is formed in the second mounting plate, one end of the adjusting screw rod sequentially penetrates through the first nut, the first through hole and the second nut, and the other end of the adjusting screw rod sequentially penetrates through the third nut, the second through hole and the fourth nut; and external threads on the adjusting screw rod are matched with internal threads of the first nut, the second nut, the third nut and the fourth nut, so that the distance between parts to be welded can be adjusted, accurate alignment of welding interfaces is ensured, stable fixing support is provided in the welding process, and the welding precision is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel engineering machinery, in particular to a welding auxiliary device and a shield body assembly welding auxiliary fixture for a shield machine, which is specifically suitable for shield body assembly welding of a shield machine. Background Art

[0002] A shield machine is a comprehensive construction machine that integrates multiple functions, including tunneling, slag removal, and support. As one of its core components, the shield bears immense earth and water pressure while maintaining high structural integrity and sealing to ensure stability and safety during tunneling. Therefore, welding quality during shield assembly is particularly important. Traditional shield assembly and welding work can easily lead to deformation due to the heavy workload. The shield is typically composed of multiple large metal components, which require precise alignment before welding. However, due to material properties, machining errors, and component movement and deformation during welding, ensuring accurate welding is difficult. Furthermore, existing welding aids are often limited to simple positioning fixtures or manual adjustment devices, making it difficult to achieve high-precision alignment and fixation in complex and changing welding environments. Especially during the assembly of large shields, due to the large size and weight of the components, traditional manual or semi-automatic alignment methods are not only inefficient but also difficult to achieve ideal welding accuracy.

[0003] In view of the above technical problems, there is an urgent need for a welding auxiliary tool that is efficient, accurate and can precisely adjust the relative positions between the components to be welded to ensure the accurate alignment of the welding interface; at the same time, it can provide stable fixed support during the welding process, thereby improving the precision control problem during the shield assembly welding process of the shield machine. Summary of the Invention

[0004] The purpose of the utility model is to overcome the problem in the prior art that deformation is easily caused due to the large welding workload during the shield assembly and welding work of the shield body of the shield machine, and to provide a welding auxiliary device and a shield body welding auxiliary fixture that ensure the accurate alignment of the welding interface and provide stable fixed support during the welding process.

[0005] In order to achieve the above objectives, the technical solution of the present utility model is:

[0006] A welding auxiliary device, comprising a first mounting plate, a second mounting plate, and an adjustment device, wherein the bottom of the first mounting plate is connected to a first component to be welded, and a first through hole is formed on the first mounting plate; the bottom of the second mounting plate is connected to a second component to be welded, and a second through hole corresponding to the first through hole is formed on the second mounting plate;

[0007] The adjusting device cooperates with the first through hole and the second through hole to adjust the distance between the first mounting plate and the second mounting plate. The adjusting device includes an adjusting screw, a first nut, a second nut, a third nut and a fourth nut. One end of the adjusting screw passes through the first nut, the first through hole and the second nut in sequence, and the other end of the adjusting screw passes through the third nut, the second through hole and the fourth nut in sequence. The external thread on the adjusting screw cooperates with the internal thread of the first nut, the second nut, the third nut and the fourth nut.

[0008] A first rib is provided between the first mounting plate and the first component to be welded, the side of the first rib is vertically connected to the first mounting plate, and the bottom of the first rib is connected to the first component to be welded;

[0009] A second rib plate is provided between the second mounting plate and the second component to be welded, the side of the second rib plate is vertically connected to the second mounting plate, and the bottom of the second rib plate is connected to the second component to be welded.

[0010] Two first through holes are symmetrically provided on the first mounting plate, and two second through holes are symmetrically provided on the second mounting plate. The two first through holes and the two second through holes are arranged in a one-to-one correspondence, and each group of corresponding first through holes and second through holes cooperates with one of the adjustment devices.

[0011] The first rib is located between the two first through holes, and the second rib is located between the two second through holes.

[0012] Annular washers are provided between the first nut and the first mounting plate, between the first mounting plate and the second nut, between the third nut and the second mounting plate, and between the second mounting plate and the fourth nut. The annular washers are sleeved on the adjusting screw.

[0013] The annular washer includes a flat washer and a spring washer. The first nut and the second nut are pressed together with the first mounting plate through the spring washer and the flat washer respectively. The third nut and the fourth nut are pressed together with the second mounting plate through the spring washer and the flat washer respectively.

[0014] The shield machine shield body welding auxiliary fixture includes a plurality of the above-mentioned welding auxiliary devices;

[0015] Multiple welding auxiliary devices are arranged at equal intervals along the welding groove, and the welding groove is opened between the first component to be welded and the second component to be welded. The first component to be welded and the second component to be welded are both segmented shield shells of the shield body of the shield machine.

[0016] The first component to be welded and the second component to be welded are both arc-shaped steel plates, and the first component to be welded and the second component to be welded are located on the same cylindrical surface.

[0017] The groove is a V-shaped groove.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The present invention provides a welding auxiliary device comprising an adjustment device, a first mounting plate, and a second mounting plate. The bottoms of the first and second mounting plates are connected to two components to be welded. A first through-hole is defined in the first mounting plate, and a second through-hole corresponding to the first through-hole is defined in the second mounting plate. The adjustment device cooperates with the first and second through-holes to adjust the distance between the first and second mounting plates. The adjustment device comprises an adjustment screw, a first nut, a second nut, a third nut, and a fourth nut. One end of the adjustment screw passes through the first nut, the first through-hole, and the second nut, respectively, and the other end passes through the third nut, the second through-hole, and the fourth nut, respectively. Thus, by rotating the first, second, third, and fourth nuts, the first and second mounting plates can be slid relative to the adjustment screw, fine-tuning the spacing between the first and second mounting plates. This, in turn, changes the spacing between the two components to be welded, connected to the bottoms of the first and second mounting plates, to meet welding process requirements and facilitate the assembly welding of the two components to be welded. Therefore, the present design can accurately adjust the spacing between the components to be welded, facilitating the assembly welding of the two components to be welded.

[0020] 2. In a welding auxiliary device of the present invention, a first rib is provided on the outer side of the first mounting plate, and a second rib is provided on the outer side of the second mounting plate. The rib is provided to increase the structural strength of the welding auxiliary device, which facilitates the assembly welding operation of large equipment. At the same time, two first through holes are symmetrically provided on the first mounting plate, and two second through holes are symmetrically provided on the second mounting plate. The two first through holes correspond to the two second through holes in a one-to-one manner, and each group of corresponding first through holes and second through holes is slidably matched with an adjusting screw. Each welding auxiliary device is adjusted by two adjusting screws and matching nuts, and the adjustment accuracy is high. Therefore, in this design, ribs are provided at both the first mounting plate and the second mounting plate to enhance their structural strength. At the same time, each welding auxiliary device adjusts the spacing of the components to be welded by two adjusting screws and matching nuts, and the adjustment accuracy is high.

[0021] 3. In this welding auxiliary device, a spring washer and a flat washer are provided between the nut and the mounting plate. The spring washer is used to increase friction after the nut is tightened, preventing the nut from loosening due to vibration or temperature changes during the welding process. The flat washer is used to prevent scratches on the mounting plate caused by friction and extrusion, thereby improving the connection stability and further more stably fixing the relative position of the components to be welded. Therefore, this design uses spring washers and flat washers to prevent the nut from loosening during the welding process, improve the connection stability, and further more stably fix the relative position of the components to be welded.

[0022] 4. In the shield body welding auxiliary fixture of the present invention, multiple welding auxiliary devices are arranged at equal intervals along the welding groove of the component to be welded. Since the shield body component of the shield machine is a large structural part, the shield body of the shield machine is usually assembled and welded by multiple arc-shaped block shields. The welding workload is large and the welding groove is long, which makes it difficult to accurately dock and fix the components to be welded during the welding process. During the welding process, the movement or deformation of the components can easily affect the welding accuracy. By using multiple welding auxiliary devices, the alignment time of the components to be welded can be saved, and the docking and fixing of the block shields can be facilitated. At the same time, by using multiple welding auxiliary devices, the distance between the components to be welded can be fine-tuned, thereby improving the welding accuracy. Therefore, in this design, by arranging multiple welding auxiliary devices at equal intervals along the welding groove of the components to be welded, the alignment time of the components to be welded can be saved, and the distance between the components to be welded can be fine-tuned, which is conducive to improving the welding accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of the present utility model.

[0024] Figure 2 It is a schematic diagram of the top view of the welding auxiliary device.

[0025] Figure 3 It is a structural diagram of the shield machine shield body welding auxiliary fixture.

[0026] In the figure: adjusting screw 1, first nut 11, second nut 12, third nut 13, fourth nut 14, first mounting plate 2, first through hole 21, first rib 22, second mounting plate 3, second through hole 31, second rib 32, annular washer 4, flat washer 41, spring washer 42, first component to be welded 10, second component to be welded 20, welding groove 30. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0028] See also Figures 1 to 3 A welding auxiliary device includes an adjustment device, a first mounting plate 2, and a second mounting plate 3. The bottom of the first mounting plate 2 is connected to the first component to be welded 10, and the first mounting plate 2 is provided with a first through hole 21. The bottom of the second mounting plate 3 is connected to the second component to be welded 20, and the second mounting plate 3 is provided with a second through hole 31 corresponding to the first through hole 21.

[0029] The adjusting device cooperates with the first through hole 21 and the second through hole 31 to adjust the distance between the first mounting plate 2 and the second mounting plate 3. The adjusting device includes an adjusting screw 1, a first nut 11, a second nut 12, a third nut 13 and a fourth nut 14. One end of the adjusting screw 1 passes through the first nut 11, the first through hole 21 and the second nut 12 in sequence, and the other end of the adjusting screw 1 passes through the third nut 13, the second through hole 31 and the fourth nut 14 in sequence. The external thread on the adjusting screw 1 cooperates with the internal thread of the first nut 11, the second nut 12, the third nut 13 and the fourth nut 14.

[0030] A first rib plate 22 is provided between the first mounting plate 2 and the first component to be welded 10. The side of the first rib plate 22 is vertically connected to the first mounting plate 2, and the bottom of the first rib plate 22 is connected to the first component to be welded 10.

[0031] A second rib plate 32 is provided between the second mounting plate 3 and the second component to be welded 20 . The side of the second rib plate 32 is vertically connected to the second mounting plate 3 , and the bottom of the second rib plate 32 is connected to the second component to be welded 20 .

[0032] The first rib plate 22 and the second rib plate 32 are provided to strengthen the structural strength of the welding auxiliary device, so as to prevent the first mounting plate 2 and the second mounting plate 3 from being deformed under the influence of the weight of the large structural member during welding, thereby affecting the welding accuracy.

[0033] The first mounting plate 2 has two symmetrical first through holes 21, and the second mounting plate 3 has two symmetrical second through holes 31. The two first through holes 21 and the two second through holes 31 are arranged in a one-to-one correspondence, and each set of corresponding first through holes 21 and second through holes 31 cooperates with one of the adjustment devices. Specifically, Figure 2 As shown, in each welding auxiliary device, two adjusting devices are symmetrically arranged, and each adjusting device consists of an adjusting screw 1 and a first nut 11, a second nut 12, a third nut 13 and a fourth nut 14. Through the above two sets of adjusting mechanisms, the distance between the two welding bodies can be adjusted conveniently and quickly to ensure that the distance between the welding bodies is the size required by the process.

[0034] The first rib 22 is located between the two first through holes 21, and the second rib 32 is located between the two second through holes 31. Figure 2 As shown, the two first through holes 21 and the first rib 22 are symmetrically arranged with the symmetry plane being the same, and the two second through holes 31 are symmetrically arranged with the second rib 32 being the symmetry plane.

[0035] An annular washer 4 is provided between the first nut 11 and the first mounting plate 2, between the first mounting plate 2 and the second nut 12, between the third nut 13 and the second mounting plate 3, and between the second mounting plate 3 and the fourth nut 14. The annular washer 4 is sleeved on the adjusting screw 1.

[0036] like Figure 1 、 Figure 2 As shown, the annular washer 4 includes a flat washer 41 and a spring washer 42. The spring washer 42 is arranged close to the nut. The first nut 11 and the second nut 12 are pressed together with the first mounting plate 2 through the spring washer 42 and the flat washer 41 in turn. The third nut 13 and the fourth nut 14 are pressed together with the second mounting plate 3 through the spring washer 42 and the flat washer 41 in turn.

[0037] The spring washer 42 provides a continuous spring force after the nut is tightened, thereby increasing friction and preventing the nut from loosening due to vibration or temperature changes during the welding process. The flat washer 41 prevents scratches on the mounting plate due to friction and compression, improves the connection stability, and thus more stably fixes the relative position of the components to be welded.

[0038] The invention discloses a shield body welding auxiliary fixture for a shield machine, which is used for welding a plurality of shield shell blocks together to finally obtain a cylindrical shield body of the shield machine.

[0039] When the first component to be welded 10 and the second component to be welded 20 are welded together, Figure 3 As shown, the first component to be welded 10 and the second component to be welded 20 are both curved steel plates, and the first curved shell 10 and the second curved shell 20 are arranged in sequence on the same cylindrical surface. A welding groove 30 is defined at the connection between the first component to be welded 10 and the second component to be welded 20. Specifically, the groove 30 can be a V-shaped groove, or other groove shapes such as a U-shaped groove, a K-shaped groove, or an X-shaped groove.

[0040] Since the shield body of the shield machine is a large structural component and has a long length along the welding groove 30 , a plurality of welding auxiliary devices are arranged at equal intervals along the welding groove 30 to ensure welding accuracy.

[0041] Before welding, the positional relationship between the first component to be welded 10 and the second component to be welded 20 (the two segmented shields to be welded) is preliminarily determined. According to the positional relationship between the first component to be welded 10 and the second component to be welded 20, the first mounting plate 2 and the second mounting plate 3 in the welding auxiliary device are respectively welded to both sides of the welding groove 30.

[0042] Subsequently, the first assembly to be welded 10 and the second assembly to be welded 20 are spliced together by the shield body welding auxiliary fixture of the shield machine. Specifically, for each welding auxiliary device set at the welding groove 30, the first mounting plate 2 and the second mounting plate 3 in the welding auxiliary device are first aligned, and one end of the adjusting screw 1 is passed through the first nut 11, the first through hole 21 and the second nut 12 on the first mounting plate 2 in sequence, and the other end of the adjusting screw 1 is passed through the third nut 13, the second through hole 31 on the second mounting plate 3 and the fourth nut 14 in sequence, and the first nut 11, the second nut 12, the third nut 13 and the fourth nut 14 are rotated to fine-tune the connection. The spacing between the first component to be welded 10 at the bottom of the first mounting plate 2 and the second component to be welded 20 connected to the bottom of the second mounting plate 3 is adjusted so that the spacing between the first component to be welded 10 and the second component to be welded 20 meets the process requirements, and then the first nut 11 and the second nut 12 are tightened to fix the position of the first component to be welded 10, and the third nut 13 and the fourth nut 14 are tightened to fix the position of the second component to be welded 20. At this time, the relative positions of the first component to be welded 10 and the second component to be welded 20 are fixed, and then the welding groove 30 is bottom welded and filled welded, and the first component to be welded 10 and the second component to be welded 20 are welded together.

[0043] Through multiple welding auxiliary devices, the spacing between the first component to be welded 10 and the second component to be welded 20 at various positions along the welding groove 30 is adjusted, and the two shield shells to be welded are fixed by the welding auxiliary devices, which effectively reduces the deformation and relative displacement of the shield shells during the welding process and effectively improves the welding accuracy.

[0044] By using the above method, multiple shield shells are welded together so that the multiple shield shells are welded on the same circle to obtain a complete shield body of the shield machine.

[0045] The principle of this utility model is described as follows:

[0046] When two components to be welded need to be welded, according to the welding requirements, the first mounting plate 2 is welded on the first component to be welded 10 near the welding groove, and the second mounting plate 3 is welded on the second component to be welded 20 near the welding groove 30. The first mounting plate 2 and the second mounting plate 3 are connected by adjusting the screw 1, so that one end of the adjusting screw 1 passes through the first nut 11, the first through hole 21 and the second nut 12 in sequence, and the other end of the adjusting screw 1 passes through the third nut 13, the second through hole 31 and the fourth nut 14 in sequence. Then, by rotating the nuts, fine-tune the distance between the first mounting plate 2 and the second mounting plate 3 so that the distance between the first component to be welded 10 and the second component to be welded 20 meets the process requirements. Then, the position of the first component to be welded 10 is fixed by the first nut 11 and the second nut 12, and the position of the second component to be welded 20 is fixed by the third nut 13 and the fourth nut 14. At this time, the relative positions of the first component to be welded 10 and the second component to be welded 20 are fixed, and then the welding operation is performed on the welding groove 30.

[0047] Example 1:

[0048] A welding auxiliary device, the welding auxiliary device includes a first mounting plate 2, a second mounting plate 3 and an adjusting device, the bottom of the first mounting plate 2 is connected to the first component to be welded 10, the first mounting plate 2 is provided with a first through hole 21, the bottom of the second mounting plate 3 is connected to the second component to be welded 20, and the second mounting plate 3 is provided with a second through hole 31 corresponding to the first through hole 21; the adjusting device cooperates with the first through hole 21 and the second through hole 31 to adjust the distance between the first mounting plate 2 and the second mounting plate 3, the adjusting device includes an adjusting screw 1, a first nut 11, a second nut 12, a third nut 13 and a fourth nut 14, one end of the adjusting screw 1 passes through the first nut 11, the first through hole 21 and the second through hole 31 in sequence Hole 21 and the second nut 12, the other end of the adjusting screw 1 passes through the third nut 13, the second through hole 31 and the fourth nut 14 in sequence, and the external thread on the adjusting screw 1 cooperates with the internal thread of the first nut 11, the second nut 12, the third nut 13 and the fourth nut 14; a first rib plate 22 is arranged between the first mounting plate 2 and the first component to be welded 10, the side of the first rib plate 22 is vertically connected to the first mounting plate 2, and the bottom of the first rib plate 22 is connected to the first component to be welded 10; a second rib plate 32 is arranged between the second mounting plate 3 and the second component to be welded 20, the side of the second rib plate 32 is vertically connected to the second mounting plate 3, and the bottom of the second rib plate 32 is connected to the second component to be welded 20.

[0049] Example 2:

[0050] Example 2 is basically the same as Example 1, except that:

[0051] Two first through holes 21 are symmetrically provided on the first mounting plate 2, and two second through holes 31 are symmetrically provided on the second mounting plate 3. The two first through holes 21 and the two second through holes 31 are arranged in a one-to-one correspondence, and each group of corresponding first through holes 21 and second through holes 31 cooperates with one of the adjustment devices; the first rib plate 22 is located between the two first through holes 21, and the second rib plate 32 is located between the two second through holes 31.

[0052] Example 3:

[0053] Example 3 is basically the same as Example 2, except that:

[0054] An annular washer 4 is provided between the first nut 11 and the first mounting plate 2, between the first mounting plate 2 and the second nut 12, between the third nut 13 and the second mounting plate 3, and between the second mounting plate 3 and the fourth nut 14. The annular washer 4 is sleeved on the adjusting screw 1; the annular washer 4 includes a flat washer 41 and a spring washer 42, and the spring washer 42 is arranged close to the nut. The first nut 11 and the second nut 12 are pressed and fitted with the first mounting plate 2 in turn through the spring washer 42 and the flat washer 41, and the third nut 13 and the fourth nut 14 are pressed and fitted with the second mounting plate 3 in turn through the spring washer 42 and the flat washer 41.

[0055] Example 4:

[0056] A shield machine shield body welding auxiliary fixture, the shield machine shield body welding auxiliary fixture includes multiple welding auxiliary devices described in Example 1; multiple welding auxiliary devices are arranged at equal intervals along the welding groove 30, the welding groove 30 is opened between the first component to be welded 10 and the second component to be welded 20, the first component to be welded 10 and the second component to be welded 20 are both block shield shells of the shield body of the shield machine; the first component to be welded 10 and the second component to be welded 20 are both arc-shaped steel plates, and the first arc-shaped shell 10 and the second arc-shaped shell 20 are arranged in sequence on the same cylindrical surface; the groove 30 is a V-shaped groove.

[0057] The above description is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the content disclosed in the present invention should be included in the protection scope recorded in the claims.

Claims

1. A welding auxiliary device, characterized in that: The welding auxiliary device comprises a first mounting plate (2), a second mounting plate (3) and an adjusting device, wherein the bottom of the first mounting plate (2) is connected to the first component to be welded (10), and the first mounting plate (2) is provided with a first through hole (21); the bottom of the second mounting plate (3) is connected to the second component to be welded (20), and the second mounting plate (3) is provided with a second through hole (31) corresponding to the first through hole (21); The adjusting device cooperates with the first through hole (21) and the second through hole (31) to adjust the distance between the first mounting plate (2) and the second mounting plate (3). The adjusting device comprises an adjusting screw (1), a first nut (11), a second nut (12), a third nut (13) and a fourth nut (14). One end of the adjusting screw (1) passes through the first nut (11), the first through hole (21) and the second nut (12) in sequence, and the other end of the adjusting screw (1) passes through the third nut (13), the second through hole (31) and the fourth nut (14) in sequence. The external thread on the adjusting screw (1) cooperates with the internal thread of the first nut (11), the second nut (12), the third nut (13) and the fourth nut (14).

2. A welding auxiliary device according to claim 1, characterized in that: A first rib plate (22) is provided between the first mounting plate (2) and the first assembly to be welded (10), the side of the first rib plate (22) being vertically connected to the first mounting plate (2), and the bottom of the first rib plate (22) being connected to the first assembly to be welded (10); A second rib plate (32) is provided between the second mounting plate (3) and the second assembly to be welded (20), the side of the second rib plate (32) being vertically connected to the second mounting plate (3), and the bottom of the second rib plate (32) being connected to the second assembly to be welded (20).

3. A welding auxiliary device according to claim 2, characterized in that: Two first through holes (21) are symmetrically provided on the first mounting plate (2), and two second through holes (31) are symmetrically provided on the second mounting plate (3). The two first through holes (21) and the two second through holes (31) are arranged in a one-to-one correspondence, and each group of corresponding first through holes (21) and second through holes (31) cooperates with one of the adjustment devices.

4. A welding auxiliary device according to claim 3, characterized in that: The first rib (22) is located between the two first through holes (21), and the second rib (32) is located between the two second through holes (31).

5. The welding auxiliary device according to claim 1, characterized in that: An annular washer (4) is provided between the first nut (11) and the first mounting plate (2), between the first mounting plate (2) and the second nut (12), between the third nut (13) and the second mounting plate (3), and between the second mounting plate (3) and the fourth nut (14), and the annular washer (4) is sleeved on the adjusting screw (1).

6. A welding auxiliary device according to claim 5, characterized in that: The annular washer (4) comprises a flat washer (41) and a spring washer (42); the first nut (11) and the second nut (12) are press-fitted with the first mounting plate (2) via the spring washer (42) and the flat washer (41) in sequence; the third nut (13) and the fourth nut (14) are press-fitted with the second mounting plate (3) via the spring washer (42) and the flat washer (41) in sequence.

7. A shield machine shield welding auxiliary fixture, characterized by: The shield machine shield welding auxiliary fixture includes a plurality of welding auxiliary devices according to any one of claims 1 to 5; A plurality of the welding auxiliary devices are arranged at equal intervals along the welding groove (30), and the welding groove (30) is opened between the first component to be welded (10) and the second component to be welded (20), and the first component to be welded (10) and the second component to be welded (20) are both block shield shells of the shield body of the shield machine.

8. The shield welding auxiliary fixture for a shield machine according to claim 7, characterized in that: The first component to be welded (10) and the second component to be welded (20) are both arc-shaped steel plates, and the first component to be welded (10) and the second component to be welded (20) are located on the same cylindrical surface.

9. The shield welding auxiliary fixture for a shield machine according to claim 7, characterized in that: The groove (30) is a V-shaped groove.

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