Core gripping method and core gripping device

Abstract

To provide a core gripping method which can obtain sufficient gripping force.SOLUTION: A method for gripping a core used for casting has: a preparation step for preparing a core with at least one of a projection and a groove open on the surface, as a core; an arrangement step for arranging a suction nozzle in contact with the core in such a manner that at least one of the external side face of the projection and the internal side face of the groove comes in contact with the inner circumferential face of the suction nozzle; and a suction step for creating negative pressure inside the suction nozzle.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a core gripping method and a core gripping device. [Background technology]

[0002] Various methods for gripping cores used in casting have been proposed. For example, Patent Document 1 discloses a method for gripping cores using multiple pickers with expandable and contractible gripping parts at their tips. In this method, the gripping parts are inserted into holes in the core, and then the gripping parts are expanded to grip the core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-061989 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology for gripping the core as described above, there is a demand for a technology that can improve the gripping force on the core. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a method for gripping a core used in casting, the method comprising: a preparation step of preparing a core having at least one of a protrusion and a groove opening on its outer surface; an arrangement step of arranging the suction nozzle on the core so that at least one of an outer side surface of the protrusion and an inner side surface of the groove faces an inner peripheral surface of the suction nozzle; and a suction step of creating a negative pressure inside the suction nozzle. According to this configuration, the suction nozzle is positioned on the core so that at least one of the outer side surface of the protrusion and the inner side surface of the groove faces the inner surface of the suction nozzle. Therefore, compared to a configuration in which the inner surface of the suction nozzle does not face the core, the suction force of the suction nozzle is increased during the suction process, thereby obtaining a greater gripping force. (2) In the method for holding a core of the above form, the positioning step may include a step of positioning the suction nozzle in contact with the core so that the portion of the inner surface of the suction nozzle that contacts at least one of the outer side surface of the protrusion and the inner side surface of the groove is parallel to at least one of the outer side surface of the protrusion and the inner side surface of the groove. According to this configuration, in the placement step, the suction nozzle is placed in contact with the core so that the portion of its inner peripheral surface that contacts at least one of the outer side surface of the protrusion and the inner side surface of the groove is parallel to at least one of the outer side surface of the protrusion and the inner side surface of the groove, thereby making it possible to increase the contact area between the inner peripheral surface of the suction nozzle and the core compared to a configuration in which the inner peripheral surface of the suction nozzle is not in contact with at least one of the outer side surface of the protrusion and the outer side surface of the groove in parallel, thereby increasing the suction force of the suction nozzle in the suction step and obtaining a greater gripping force. (3) In the method for gripping a core of the above-described form, the protrusion may have a columnar external shape, and the positioning step may include a step of positioning the suction nozzle on the core so that the suction nozzle surrounds the entire protrusion. According to this configuration, the suction nozzle is positioned facing the core so as to surround the entire protrusion, and therefore, compared to a configuration in which only a portion of the protrusion is covered, the suction force of the suction nozzle can be increased during the suction process, resulting in a greater gripping force. (4) In the method for holding a core of the above form, the groove portion may have a ring-shaped external shape in a plan view, and the positioning step may include a step of positioning the suction nozzle in the core so that the tip of the suction nozzle is inserted around the entire circumference of the groove portion. According to this configuration, the suction nozzle is positioned in the core so that the tip of the suction nozzle is inserted around the entire circumference of the groove portion. Therefore, compared to a configuration in which the suction nozzle is inserted into only a portion of the groove portion, the suction force of the suction nozzle can be increased during the suction process, resulting in a greater gripping force. (5) In the method for holding a core of the above-described form, the preparation step may include a step of preparing a core formed so that the protrusion and the groove are continuous as the core, and the placement step may include a step of placing the suction nozzle on the core so that both the outer side surface of the protrusion and the inner side surface of the groove face the inner peripheral surface of the suction nozzle. According to this embodiment, the protrusion and the groove are formed continuously on the core, and the suction nozzle is positioned in the positioning step so that its inner circumferential surface faces both the outer side surface of the protrusion and the inner side surface of the groove, which makes it possible to increase the facing area between the inner circumferential surface of the suction nozzle and the core compared to a configuration in which the core has only one of the protrusion and the groove and its inner circumferential surface faces only one of the outer side surface of the protrusion and the inner side surface of the groove, thereby increasing the suction force of the suction nozzle in the suction step and obtaining a greater gripping force. The present disclosure can be realized in various forms other than the core gripping method, such as a computer program that realizes the core gripping method, a non-transitory recording medium on which the computer program is recorded, a core gripping device, etc. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a core holding device according to one embodiment of the present disclosure. [Figure 2] FIG. [Figure 3] FIG. 10 is a perspective view showing an example of a core having a protrusion. [Figure 4] 4 is a flowchart showing steps of a core gripping method in the first embodiment. [Figure 5]FIG. 10 is a cross-sectional view showing an example in which a suction nozzle is arranged on a core having a protrusion. [Figure 6] FIG. 1 is a perspective view showing an example of a core having a groove. [Figure 7] FIG. 10 is a cross-sectional view showing an example in which a suction nozzle is arranged on a core having a groove. [Figure 8] FIG. 11 is a perspective view showing an example of a core according to a third embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing an example in which a suction nozzle is arranged on a core according to the third embodiment. [Figure 10] FIG. 10 is a perspective view showing an example of a core according to a fourth embodiment. [Figure 11] FIG. 10 is a perspective view showing a suction nozzle of a core holding device according to a fourth embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing an example in which a suction nozzle is arranged on a core according to a fourth embodiment. [Figure 13] FIG. 10 is a cross-sectional view showing an example of a core having both a protrusion and a groove. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: A1. Core gripping device: FIG. 1 is an explanatory diagram showing the schematic configuration of a core gripping device 100 according to one embodiment of the present disclosure. FIG. 1 shows the gripping device 100 gripping a core 20. The core 20 is a mold used to form a hollow casting during casting. The core 20 is manufactured by thermally curing resin-coated sand. The core gripping device 100 is used to grip the core 20. Note that in this embodiment, "gripping a core" has a broader meaning that includes not only grabbing a portion of the core 20 by suction, but also supporting or holding a portion of the core 20 by suction. The core gripping device 100 includes a lifter 1, an arm 2, a suction nozzle 3, a suction device 4, and a hose 5.

[0009] The lifter 1 moves the arm 2 and the suction nozzle 3 in a vertical direction D1. The lifter 1 is suspended from a rail 6 and can move along the rail 6 in a horizontal direction D2.

[0010] The arm 2 is attached to the tip of the lifter 1. A suction nozzle 3 is attached to the tip of the arm 2. The arm 2 is configured so that multiple types of suction nozzles 3 can be replaced using an auto tool changer.

[0011] FIG. 2 is a perspective view showing the suction nozzle 3. The suction nozzle 3 may be, for example, hollow cylindrical, truncated conical, or bell-shaped. The suction nozzle 3 has an inner circumferential surface 30 and a tip 31. The inner circumferential surface 30 is a circumferential surface facing the hollow portion inside the suction nozzle 3. The suction nozzle 3 is shaped so that the inner circumferential surface 30 of the suction nozzle 3 faces the outer side surface 23 of the protruding portion 21 of the core 20 (described later). The tip 31 is the end of the suction nozzle 3 and is shaped so that it can come into contact with the outer surface of the core 20. The suction nozzle 3 is made of, for example, resin, rubber, etc. The suction nozzle 3 is formed, for example, using a 3D printer.

[0012] As shown in FIG. 1, the suction device 4 sucks in outside air. The suction device 4 is connected to the suction nozzle 3 via a hose 5. The hose 5 is a pipe made of, for example, polyvinyl chloride or rubber. When the inner circumferential surface 30 of the suction nozzle 3 faces the outer side surface 23 of the protruding portion 21 of the core 20, the suction device 4 sucks in air, creating a negative pressure inside the suction nozzle 3. This causes the core 20 to be gripped by the suction nozzle 3. The phrase "the inner circumferential surface 30 faces the outer side surface 23" refers not only to cases where there is a gap between the inner circumferential surface 30 and the outer side surface 23, but also to cases where the inner circumferential surface 30 and the outer side surface 23 are in contact. Note that the tip 31 of the suction nozzle 3 and the surface of the core 20 may be in contact.

[0013] FIG. 3 is a perspective view showing an example of a core 20 having a protrusion 21. Note that FIG. 3 shows only a portion of the core 20, with the remaining portions omitted. The core 20 of this embodiment has the protrusion 21. The protrusion 21 has a columnar external shape, for example, a substantially truncated cone shape as shown in FIG. 3. The height of the protrusion 21 is, for example, 10 mm to 40 mm. The diameter of the protrusion 21 is, for example, 30 mm to 60 mm. The protrusion 21 has an outer side surface 23. The outer side surface 23 faces the inner circumferential surface 30 of the suction nozzle 3 when the suction nozzle 3 is placed on the core 20.

[0014] A2. Core gripping method: 4 is a flowchart showing the steps of the core gripping method in the first embodiment. A core 20 having a protrusion 21 is prepared (P105). Step P105 may include a step of manufacturing or preparing a core 20 provided with a protrusion 21 dedicated to gripping for carrying out the method of this embodiment. Step P105 may also include a step of manufacturing or preparing a core 20 provided with a protrusion for forming a groove in the casting. In such a case, the protrusion for forming the groove will also be used as the protrusion 21 for gripping. Step P105 is also referred to as a preparation step.

[0015] The suction nozzle 3 is placed on the core 20 so that the outer side surface 23 of the protrusion 21 faces the inner peripheral surface 30 of the suction nozzle 3 (P110). FIG. 5 is a cross-sectional view showing an example of how the suction nozzle 3 is placed on the core 20. FIG. 5 shows a cross-section of the core 20 having a protrusion 21 that is approximately truncated cone, i.e., a cross-section along the height direction of the core 20 shown in FIG. 3, along with a cross-section of the suction nozzle 3. As shown in FIG. 5, the suction nozzle 3 is placed so as to surround the entire protrusion 21. The suction nozzle 3 is also placed so that the outer side surface 23 of the protrusion 21 faces the entire periphery of the inner peripheral surface 30. The suction nozzle 3 is also placed so that the tip 31 of the suction nozzle 3 is in contact with the outer surface of the core 20. Note that step P110 is also referred to as a placement step.

[0016] The suction nozzle 3 is then placed under negative pressure to suck the core 20 (P115). After the suction nozzle 3 is placed, the suction device 4 is activated to create a negative pressure inside the suction nozzle 3. This causes the core 20 to be gripped by the suction nozzle 3. The gripped core 20 is transported to a predetermined position in the mold used for casting by operating the lifter 1, and is then placed in the mold by stopping the suction device 4. Note that step P115 is also called the suction step.

[0017] As in the core gripping method of this embodiment, the effect of positioning the suction nozzle 3 on the core 20 in the placement process (P110) so as to surround the entire protrusion 21 and so that the outer side surface 23 of the protrusion 21 faces the inner surface 30 of the suction nozzle 3 will be described.

[0018] Because the core 20 is made of sand, it has many holes on its surface and inside. The air being sucked can pass through these many holes. Therefore, when suction is performed while the protruding portion 21 is covered with the suction nozzle 3, the air passes through the core 20 (protruding portion 21) inside the suction nozzle 3, generating air resistance inside the suction nozzle 3. This air resistance creates a larger negative pressure inside the suction nozzle 3 during suction. Furthermore, by positioning the suction nozzle 3 so that the outer side surface 23 of the protruding portion 21 is in contact with the inner surface 30 of the suction nozzle 3, the suction nozzle 3 and the core 20 can be brought into closer contact, thereby creating a larger negative pressure inside the suction nozzle 3 during suction.

[0019] On the other hand, in a comparative example, when the suction nozzle 3 is in contact with the flat outer surface of the core 20 only at its tip 31, there is almost no area of ​​the core 20 inside the suction nozzle 3, so air resistance inside the suction nozzle 3 is smaller and it is not possible to obtain a large negative pressure inside the suction nozzle 3 compared to the core gripping method of this embodiment. Also, in the comparative example, the suction nozzle 3 and core 20 are in contact only at the tip 31, so air is more likely to leak out of the suction nozzle 3 during suction compared to the core gripping method of this embodiment. In this way, the core gripping method of this embodiment can obtain a larger negative pressure inside the suction nozzle 3 during suction compared to the core gripping method of the comparative example, so the suction force of the suction nozzle 3 can be made larger and the gripping force of the core 20 can be made larger.

[0020] A3. Evaluation of gripping force: The gripping force was evaluated for two cases: when the suction nozzle 3 was positioned on a generally truncated cone-shaped protrusion 21 as shown in FIGS. 3 and 5 so that the outer side surface 23 of the protrusion 21 faced the inner peripheral surface 30 of the suction nozzle 3; and when the suction nozzle 3 was positioned so that only the tip 31 was in contact with the flat outer surface of the core 20. In this embodiment, the "gripping force" refers to the weight of the largest core 20 that can be gripped by the gripping device 100. The gripping force was evaluated by hanging various weights from the pre-weighed core 20, in order from lightest to heaviest, on the core 20 and determining the total weight of the core 20 and the weights just before the core 20 could no longer be gripped. The suction nozzle 3 used had a hollow, generally cylindrical shape as shown in FIG. 2, and was shaped so that the outer side surface 23 of the protrusion 21 faced the inner peripheral surface 30 of the suction nozzle 3 along the entire circumference. When the suction nozzle 3 was placed on the protrusion 21, the gripping force was 9.3 kg. On the other hand, when the suction nozzle 3 was placed on a flat outer surface, the gripping force was 5.4 kg. As described above, it was found that by placing the suction nozzle 3 so that the outer side surface 23 of the protrusion 21 faces the inner circumferential surface 30 of the suction nozzle 3, it is possible to increase the gripping force compared to a configuration in which the suction nozzle 3 is placed on a flat outer surface. This is thought to be because, first, the presence of the core 20 (protrusion 21) inside the suction nozzle 3 generates air resistance within the suction nozzle 3 during suction, resulting in a larger negative pressure within the suction nozzle 3; and second, by placing the suction nozzle 3 so that the outer side surface 23 of the protrusion 21 faces the inner circumferential surface 30 of the suction nozzle 3 over the entire circumference, a larger negative pressure is generated within the suction nozzle 3 during suction.

[0021] According to the core gripping device 100 of the first embodiment described above, the suction nozzle 3 is configured so that it can be positioned so that the inner circumferential surface 30 faces the outer side surface 23 of the protruding portion 21 of the core 20, and therefore, compared to a configuration in which the inner circumferential surface 30 does not face the outer side surface 23, a greater negative pressure can be obtained within the suction nozzle 3 when the suction device 4 is operating. In other words, a greater suction force can be obtained, and the core 20 can be gripped with a greater gripping force.

[0022] Furthermore, according to the core gripping method of the first embodiment described above, in the placement step (P110), the suction nozzle 3 is placed on the core 20 so that the outer side surface 23 of the protrusion 21 faces the inner circumferential surface 30 of the suction nozzle 3, so that a greater negative pressure can be obtained inside the suction nozzle 3 during suction, compared to a configuration in which the outer side surface 23 and the inner circumferential surface 30 are not placed face to face. In other words, a greater suction force can be obtained, and the core 20 can be gripped with a greater gripping force.

[0023] Furthermore, the protrusion 21 of the core 20 prepared in the preparation step (P105) may not only be a protrusion provided on the core 20 for the sole purpose of gripping, but may also be a protrusion provided for forming a groove in the casting to be cast using the core 20. Therefore, by using such a protrusion to grip the core 20, the gripping force can be easily increased.

[0024] Furthermore, since the core 20 is gripped by suction, damage to the core 20 due to external forces can be reduced even when a relatively heavy core 20 is gripped, compared to a configuration in which the core 20 is clamped by a robot arm.

[0025] Furthermore, since the core 20 is grasped by suction, no space is required to insert the robot arm, compared to a configuration in which the core 20 is scooped up from below with a robot arm, and even cores 20 with complex shapes can be grasped.

[0026] B. Second embodiment: B1. Shape of core 20: FIG. 6 is a perspective view showing an example of a core 20 having a groove 22. Note that FIG. 6 shows only a portion of the core 20, omitting the other portions. While the core 20 of the first embodiment had a protrusion 21, the core 20 of the second embodiment has a groove 22 instead of the protrusion 21. The groove 22 is a depression that opens into the outer surface of the core 20. The groove 22 has a substantially annular external shape in a plan view. The depth of the groove 22 is, for example, 10 mm to 40 mm. The width of the groove 22 is, for example, 2 mm. The groove 22 has an inner side surface 24. Of the side surfaces of the groove 22, the inner side surface 24 is the side surface that is closer to the inner circumferential surface 30 of the core 20 when the suction nozzle 3 is placed on the core 20. The inner side surface 24 in this embodiment is the side surface that is located more inward in a plan view.

[0027] The suction nozzle 3 in the core holding device of the second embodiment has a shape that allows it to be arranged so that the inner side surface 24 of the groove portion 22 faces the inner peripheral surface 30 of the suction nozzle 3 over the entire circumference. Such a shape is a hollow, approximately cylindrical shape as shown in FIG.

[0028] The configuration of the core holding device of the second embodiment is the same as the configuration of the core holding device 100 of the first embodiment, so a detailed description thereof will be omitted.

[0029] B2. Core gripping method: The core holding method of the second embodiment differs from the core holding method of the first embodiment in the core 20 prepared in the preparation step (P105) and the way in which the suction nozzle 3 is arranged in the arrangement step (P110). The other steps are the same as the core holding method of the first embodiment, so detailed explanations thereof will be omitted.

[0030] In the preparation step (P105) of the second embodiment, instead of the core 20 having the protrusion 21 of the first embodiment, a core 20 having a groove 22 as shown in FIG. 6 is prepared. The preparation step (P105) of the second embodiment may include a step of manufacturing or preparing a core 20 provided with a groove 22 dedicated to gripping. The preparation step (P105) may also include a step of manufacturing or preparing a core 20 provided with a groove for forming a protrusion in a casting. In such a configuration, the groove for forming the protrusion is also used as the groove 22 for gripping.

[0031] In the arrangement step (P110) of the second embodiment, the suction nozzle 3 is arranged so that the inner side surface 24 of the groove 22 faces the inner peripheral surface 30 of the suction nozzle 3. FIG. 7 is a cross-sectional view showing an example of how the suction nozzle 3 is arranged on the core 20. FIG. 7 shows a cross section of the core 20 having a groove 22 that is substantially annular in plan view, i.e., a cross section taken along the height direction of the core 20 shown in FIG. 6, together with a cross section of the suction nozzle 3. As shown in FIG. 7, the suction nozzle 3 is arranged so that the tip 31 is inserted around the entire circumference of the groove 22. The suction nozzle 3 is also arranged so that the tip 31 is in contact with the outer surface of the core 20.

[0032] According to the core gripping device of the second embodiment described above, the suction nozzle 3 is configured so that it can be positioned so that the inner circumferential surface 30 faces the inner side surface 24 of the groove portion 22 of the core 20, and therefore, compared to a configuration in which the inner circumferential surface 30 does not face the inner side surface 24, a greater negative pressure can be obtained within the suction nozzle 3 when the suction device 4 is operating. In other words, a greater suction force can be obtained, and the core 20 can be gripped with a greater gripping force.

[0033] Furthermore, according to the core gripping method of the second embodiment described above, in the placement step (P110), the suction nozzle 3 is placed on the core 20 so that the inner side surface 24 of the groove 22 faces the inner circumferential surface 30 of the suction nozzle 3, so that a greater negative pressure can be obtained inside the suction nozzle 3 during suction, compared to a configuration in which the inner side surface 24 and the inner circumferential surface 30 are not placed face to face. In other words, a greater suction force can be obtained, and the core 20 can be gripped with a greater gripping force.

[0034] Furthermore, the groove portion 22 of the core 20 prepared in the preparation step (P105) may not only be a groove provided in the core 20 for the exclusive purpose of gripping, but may also be a groove provided for forming a protrusion on the casting to be cast using the core 20. Therefore, by using such a groove to grip the core 20, the gripping force can be easily increased.

[0035] Furthermore, since the core 20 is gripped by suction, damage to the core 20 due to external forces can be reduced even when a relatively heavy core 20 is gripped, compared to a configuration in which the core 20 is clamped by a robot arm.

[0036] Furthermore, since the core 20 is grasped by suction, no space is required to insert the robot arm, compared to a configuration in which the core 20 is scooped up from below with a robot arm, and therefore even cores 20 having complex shapes can be grasped.

[0037] C. Third embodiment: C1. Shape of core 20: Fig. 8 is a perspective view showing an example of a core 20 of the third embodiment. Note that Fig. 8 shows only a portion of the core 20, with the remaining portions omitted. While the core 20 of the first embodiment had a protrusion 21 that was approximately frustum-shaped, the core 20 of the third embodiment has a protrusion 21a that is an annular sector-shaped pillar. In other words, the annular sector-shaped pillar is a pillar whose cross section in the height direction is approximately arc-shaped.

[0038] The core holding device of the third embodiment has the same configuration as the core holding device 100 of the first embodiment, and therefore detailed description thereof will be omitted.

[0039] C2. Core gripping method: The core holding method of the third embodiment differs from the core holding method of the first embodiment in that, in the placement step (P110), the suction nozzle 3 is placed so that the outer side surface 23a of the protrusion 21a faces a part of the inner peripheral surface 30 of the suction nozzle 3. The other steps are the same as the core holding method of the first embodiment, so detailed description thereof will be omitted.

[0040] Fig. 9 is a cross-sectional view showing an example of how a suction nozzle 3 is arranged on a core 20 of the third embodiment. Fig. 9 shows a cross section of a core 20 having a protruding portion 21a that is an annular sector shape in a plan view, i.e., a cross section along the height direction of the core 20 shown in Fig. 8, together with the suction nozzle 3. As shown in Fig. 9, the suction nozzle 3 is arranged so that a portion of the inner circumferential surface 30 faces the outer side surface 23a on the radially outer side of the protruding portion 21a. Even with this arrangement, air resistance is generated at the protruding portion 21a inside the suction nozzle 3 during suction, and a larger negative pressure can be obtained inside the suction nozzle 3. This increases the suction force of the suction nozzle 3, thereby increasing the gripping force.

[0041] The core holding device and core holding method of the third embodiment described above have the same effects as the core holding device 100 and core holding method of the first embodiment.

[0042] D. Fourth embodiment: D1. Shape of the core 20 and the suction nozzle 3a: FIG. 10 is a perspective view showing an example of a core 20 of the fourth embodiment. Note that FIG. 10 shows only a portion of the core 20, with the remaining portions omitted. While the core 20 of the second embodiment had a groove 22 that was approximately annular in plan view, the core 20 of the fourth embodiment has a groove 22a that is an annular sector in plan view. The groove 22a of the fourth embodiment can also be said to be a partially filled-in version of the groove 22 of the second embodiment. The groove 22a has an inner side surface 24a. The inner side surface 24a is one of the side surfaces of the groove 22a. In this embodiment, a case will be described in which the inner side surface 24a is the radially inner surface of the annular sector.

[0043] Fig. 11 is a perspective view showing a suction nozzle 3a in a core gripping device according to the fourth embodiment. As shown in Fig. 11, the suction nozzle 3a of the fourth embodiment has an insertion portion 33. The insertion portion 33 is a portion that protrudes from the tip side of the suction nozzle 3. The insertion portion 33 is inserted into the groove portion 22a.

[0044] The core holding device of the fourth embodiment has the same configuration as the core holding device of the first embodiment except for the shape of the suction nozzle 3a, so a detailed description thereof will be omitted.

[0045] D2. Core gripping method: The core holding method of the fourth embodiment differs from the core holding method of the second embodiment in that, in the placement step (P110), the suction nozzle 3a is placed so that the inner side surface 24a of the groove portion 22a faces the inner circumferential surface 30a of the insertion portion 33. The other steps are the same as the core holding method of the second embodiment, so detailed explanations thereof will be omitted.

[0046] FIG. 12 is a cross-sectional view showing an example of the arrangement of a suction nozzle 3a on a core 20 of the fourth embodiment. FIG. 12 shows a cross section of a core 20 having an annular sector-shaped groove 22a in a plan view, i.e., a cross section along the height direction of the core 20 shown in FIG. 10, along with the suction nozzle 3a. As shown in FIG. 12, the suction nozzle 3a is arranged so that a portion of the inner circumferential surface 30 on the tip side, i.e., the inner circumferential surface 30a of the insertion portion 33, faces the inner side surface 24a of the groove 22a. The suction nozzle 3a is also arranged so that both the tip 34 of the insertion portion 33 and the tip 31 of the suction nozzle 3a are in contact with the core 20. This arrangement also generates air resistance within the suction nozzle 3a during suction, allowing for a larger negative pressure within the suction nozzle 3a. This increases the suction force of the suction nozzle 3, thereby increasing the gripping force.

[0047] According to the core holding device and core holding method of the fourth embodiment described above, the same effects as those of the core holding device and core holding method of the second embodiment are achieved.

[0048] E. Other Embodiments: (E1) In the arrangement step (P110) of the first embodiment, the suction nozzle 3 may be arranged in contact with the core 20 so that a portion of the inner circumferential surface 30 of the suction nozzle 3 that contacts the outer side surface 23 of the protrusion 21 is parallel to the outer side surface 23 of the protrusion 21. Furthermore, in the arrangement step (P110) of the second embodiment, the suction nozzle 3 may be arranged in contact with the core 20 so that a portion of the inner circumferential surface 30 of the suction nozzle 3 that contacts the inner side surface 24 of the groove 22 is parallel to the inner side surface 24 of the groove 22. This configuration increases the contact area between the inner circumferential surface 30 of the suction nozzle 3 and the core 20, thereby increasing the suction force of the suction nozzle 3 and providing a greater gripping force compared to a configuration in which the inner circumferential surface 30 of the suction nozzle 3 is not arranged in parallel to the outer side surface 23 of the protrusion 21 or the inner side surface 24 of the groove 22.

[0049] (E2) FIG. 13 is a cross-sectional view showing an example of a core 20 in which the protrusions 21 and the grooves 22 are formed so as to be continuous. In each embodiment, an example has been described in which the core 20 has either the protrusions 21 or the grooves 22, but the present disclosure is not limited to this. The core 20 may have both the protrusions 21 and the grooves 22. In this configuration, in the placement step (P110), the suction nozzle 3 may be placed on the core 20 so that both the outer side surface 23 of the protrusions 21 and the inner side surface 24 of the grooves 22 face the inner circumferential surface 30 of the suction nozzle 3. With this configuration, compared to a configuration using a core 20 having only either the protrusions 21 or the grooves 22, the facing area between the inner circumferential surface 30 of the suction nozzle 3 and the core 20 can be made larger, thereby obtaining a greater gripping force.

[0050] (E3) In each embodiment, when the core 20 has a protrusion 21, the suction nozzle 3 may be arranged so as to cover a part of the height of the protrusion 21. In other words, the tip 31 of the suction nozzle 3 does not have to be in contact with the outer surface of the core 20. Even with this configuration, a large gripping force can be obtained.

[0051] (E4) In each embodiment, when the core 20 has a groove 22, the suction nozzle 3 may be arranged so as to be inserted into a portion of the groove 22 in the height direction. In other words, the tip 31 of the suction nozzle 3 does not have to be in contact with the outer surface of the core 20. Even with this configuration, a large gripping force can be obtained.

[0052] (E5) In each embodiment, if the protrusion 21 or groove 22 has a structure provided exclusively for gripping, the groove 22 of the core 20 may be filled with a protective member after the core 20 is placed in the mold. When molten metal flows into the groove 22 and hardens, a protrusion having a shape corresponding to the groove 22 is formed in the casting. For example, if the shape of the groove 22 is approximately annular in plan view, the formation of a protrusion in the casting can be prevented by filling the groove 22 with a substantially cylindrical protective member having a through hole in the center and then pouring the molten metal into it. Note that the shape of the protective member is not limited to being approximately cylindrical and may be any shape corresponding to the groove 22.

[0053] (E6) In each embodiment, the protrusion 21 of the core 20 is described as being in the shape of a substantially truncated cone or a circular sector-shaped column, but the shape of the protrusion 21 is not limited to these. The shape of the protrusion 21 may be any shape, such as a cylinder or a rectangular parallelepiped. In such a case, the suction nozzle 3 is configured to be able to be arranged so that the outer side surface 23 and the inner peripheral surface 30 of the protrusion 21 face each other.

[0054] (E7) In each embodiment, the groove 22 of the core 20 is described as being generally annular or annular sector-shaped in plan view, but the shape of the groove 22 is not limited to these. The shape of the groove 22 may be any shape, such as a polygon, a straight line, or an arc, in plan view. In such cases, the suction nozzle 3, 3a is configured to be able to be positioned so that the inner side surface 24 of the groove 22 faces the inner circumferential surface 30.

[0055] (E8) In each embodiment, the protrusion 21 may have a tapered shape formed to become narrower toward the outside of the core 20 in a cross-sectional view. Also, the groove 22 may have a tapered shape formed so that the space of the groove 22 becomes wider toward the outside of the core 20 in a cross-sectional view. According to such an embodiment, the suction nozzle 3 can be positioned in the protrusion 21 or the groove 22 more smoothly than in a configuration in which the protrusion 21 or the groove 22 is not tapered.

[0056] (E9) In each embodiment, the number of suction nozzles 3 used for a single core 20 is not limited to one, and any number of two or more may be used.

[0057] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0058] 1...lifter, 2...arm, 3, 3a...suction nozzle, 4...suction device, 5...hose, 6...rail, 20...core, 21, 21a...protrusion, 22, 22a...groove, 23, 23a...external side, 24, 24a...internal side, 30, 30a...inner peripheral surface, 31...tip, 32...outer edge, 33...insertion portion, 34...tip, 100...core gripping device, D1...vertical direction, D2...horizontal direction

Claims

1. A method for gripping a core used in casting, comprising: a preparation step of preparing a core having at least one of a protrusion and a groove opening on an outer surface thereof; an arrangement step of arranging the suction nozzle on the core so that at least one of an outer side surface of the protrusion and an inner side surface of the groove faces an inner peripheral surface of the suction nozzle; a suction step of creating a negative pressure inside the suction nozzle; A method for gripping a core, comprising:

2. 2. The method for gripping a core according to claim 1, the positioning step includes a step of positioning the suction nozzle in contact with the core such that a portion of the inner peripheral surface of the suction nozzle that contacts at least one of the outer side surface of the protrusion and the inner side surface of the groove is parallel to at least one of the outer side surface of the protrusion and the inner side surface of the groove. Method of gripping the core.

3. 3. The method for holding a core according to claim 1 or 2, The protrusion has a columnar external shape, the arranging step includes a step of arranging the suction nozzle on the core so that the suction nozzle surrounds the entire protrusion. Method of gripping the core.

4. 3. The method for holding a core according to claim 1 or 2, The groove portion has an annular appearance shape in a plan view, the arranging step includes a step of arranging the suction nozzle in the core so that a tip of the suction nozzle is inserted around the entire circumference of the groove portion. Method of gripping the core.

5. 3. The method for holding a core according to claim 1 or 2, the preparing step includes a step of preparing a core in which the protrusion and the groove are formed so as to be continuous with each other, the arranging step includes a step of arranging the suction nozzle in the core so that both the outer side surface of the protrusion and the inner side surface of the groove face the inner peripheral surface of the suction nozzle. Method of gripping the core.

6. A core holding device used in casting, a suction nozzle having an inner peripheral surface, the suction nozzle being configured to be able to be arranged so that the inner peripheral surface faces at least one of an outer side surface of a protrusion in the core and an inner side surface of a groove that opens into the outer surface of the core; a suction device connected to the suction nozzle by a hose and configured to create a negative pressure inside the suction nozzle; A core gripping device comprising:

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