Trimming tool, can making apparatus, trimming method, and can

Abstract

To provide a trimming tool, a can manufacturing apparatus, and a trimming method capable of suppressing adhesion of metal powder to a die and reducing a forming load during diameter expansion after trimming. And to provide a can capable of suppressing the cut surface of the curl part from becoming conspicuous due to metallic luster.SOLUTION: A trimming tool 40 for trimming an opening of a cylindrical can W includes a cutting-edge 42a that cuts the opening of the can W while rotating around a central shaft C of the trimming tool 40 and forms a cut surface 105 facing one side in an axial direction in the opening, and the cutting-edge 42a extends toward one side in the axial direction as it goes inward in a radial direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a trimming tool, a can manufacturing apparatus, a trimming method, and a can. [Background technology]

[0002] BACKGROUND ART Bottle can manufacturing apparatuses (hereinafter, sometimes referred to as can manufacturing apparatuses) that manufacture bottle cans (threaded cans) by performing various processes on the openings of cylindrical cans (DI cans) have been known. For example, Patent Document 1 discloses a trimming device (trimming tool) for a bottle can manufacturing apparatus that cuts the open end of the mouth portion of a formed bottle-shaped body during the process of forming a bottle can, thereby adjusting the length of the bottle-shaped body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-251513 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of can manufacturing device, the opening of the can is sometimes trimmed with a trimming tool and then enlarged with an enlargement tool. During this enlargement process, the cut surface of the trimmed can opening comes into contact with the die used for the enlargement process, which can result in burrs and other problems, such as buildup, in which metal powder such as aluminum powder adheres from the cut surface to the die.

[0005] Furthermore, this type of can manufacturing apparatus has room for improvement in terms of reducing the forming load during the diameter expansion process after the trimming process.

[0006] Furthermore, in cans such as bottle cans, a curled portion is formed at the opening of the can. In this case, the diameter expansion process after the trimming process includes curling. The curling process causes the cut surface at the curled portion to be folded back toward the bottom of the can. In this state, the cut surface of the curled portion stands out more than its surroundings due to its metallic luster (it stands out badly), which may affect the exterior design, etc.

[0007] The present invention aims to provide a trimming tool, a can manufacturing apparatus, and a trimming method that can prevent metal powder from adhering to a mold during diameter expansion after trimming and reduce the forming load. Another object of the present invention is to provide a can that can prevent the cut surface of the curled portion from being unnoticeable due to metallic luster. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides the following means.

[0009] [Aspect 1 of the present invention] A trimming tool for trimming the opening of a cylindrical can, the trimming tool having a cutting blade that cuts the opening while rotating around a central axis of the trimming tool and forms a cutting surface on the opening that faces one axial side, the cutting blade extending radially inward toward one axial side.

[0010] In the trimming tool of the present invention, the cutting edges extend radially inward toward one axial side. That is, the cutting edges extend at an angle with respect to an imaginary plane extending in a direction (plane direction) perpendicular to the central axis of the trimming tool (corresponding to the can axis of the can). Therefore, the cut surface of the opening of the can trimmed by the cutting edges also extends at an angle toward one axial side as it extends radially inward.

[0011] By sloping the cut surface of the can in this manner, the following effects are achieved when the opening of the can is expanded with an expansion tool after trimming. That is, the expansion die is more likely to come into contact with the corner (sharp portion) where the inner circumferential surface of the can opening and the cut surface connect, while contact with the cut surface is suppressed. The metal material of the can is exposed at the cut surface, and direct contact between this cut surface and the die is suppressed, so the generation of burrs is suppressed and the phenomenon of metal powder adhering to the die (build-up) is significantly suppressed. Furthermore, by reducing the frequency of burr generation, the occurrence of thread marks and the like caused by burrs is also suppressed.

[0012] Furthermore, during the diameter expansion process, the mold first comes into contact with the corner (sharp portion) where the can wall is thin, making the open end of the can more easily deform with a small force. In other words, the open end of the can is more likely to warp and bend. This makes it possible to reduce the forming load during the diameter expansion process. Because the forming load during the diameter expansion process can be kept small, contact between the mold and the cut surface can be more reliably suppressed, build-up can be stably suppressed, and it also becomes easier to achieve thinner cans.

[0013] As described above, according to the present invention, it is possible to suppress adhesion of metal powder to the die during diameter expansion processing after trimming processing, and also to reduce the molding load.

[0014] [Aspect 2 of the present invention] The trimming tool of aspect 1, further comprising a diameter guide that is inserted into the opening along an axial direction, and the cutting blade is rotatable about the central axis relative to the diameter guide.

[0015] In this case, the cutting blade can be rotated around the central axis to form a cut surface at the opening by fitting the aperture guide into the opening of the can and fixing the opening with the aperture guide, allowing for the accurate and stable formation of a cut surface with the desired inclined surface shape.

[0016] [Embodiment 3 of the present invention] 3. The trimming tool according to claim 1, wherein an angle formed between an imaginary line perpendicular to the central axis and the cutting edge when viewed from the radial direction is 3° to 40°.

[0017] When the angle is 3° or more, contact between the die and the cut surface can be more stably suppressed during the diameter expansion process. If the angle is 40° or less, defects caused by excessive thinning of the opening edge (sharp portion) of the can are suppressed. Specifically, defects such as wavy cut shapes along the circumferential direction of the cut surface are suppressed. From the viewpoint of further enhancing the above-mentioned effects, the angle is more preferably 10° or more and 30° or less, and even more preferably 10° or more and 20° or less.

[0018] [Aspect 4 of the present invention] Aspect 4. The trimming tool according to any one of aspects 1 to 3, wherein the can is a can body for a bottle can, the opening of which is threaded with a cap.

[0019] [Embodiment 5 of the present invention] The trimming tool according to any one of aspects 1 to 3, wherein the can is a cylindrical cup body with a bottom and a peripheral wall on which the opening is located, and the peripheral wall has a diameter dimension that increases from the bottom wall toward the opening.

[0020] The trimming tool of the present invention can be applied to various types of cans (bottle cans, expanded diameter cups (cup bodies)) that are provided with a process for expanding the diameter of the opening of the can after trimming, thereby achieving the above-mentioned excellent effects.

[0021] [Aspect 6 of the present invention] a holding table that is rotated intermittently about a table axis; and a processing table that is moved back and forth relative to the holding table in the table axis direction, wherein the holding table has a plurality of chucks that hold a plurality of cans, and the processing table has a plurality of processing tools that process each of the cans held by each of the chucks, the plurality of processing tools including a trimming tool according to any one of aspects 1 to 5 and an expansion tool that expands the diameter of an opening of the can using a mold, and the trimming tool is positioned upstream of the expansion tool in the processing order for the cans around the table axis.

[0022] According to the can manufacturing apparatus of the present invention, after the trimming tool forms an inclined cut surface on the opening of the can, the opening is enlarged by the diameter enlargement tool, thereby stably achieving the above-mentioned effects.

[0023] [Embodiment 7 of the present invention] A trimming method for trimming an opening of a cylindrical can, the method comprising: rotating the can and a cutting blade relatively around a can axis of the can to cut the opening; forming a cut surface on the opening that faces one side in the can axial direction; and the cut surface extending toward one side in the can axial direction as it moves inward in the can radial direction.

[0024] According to the trimming method of the present invention, the cut surface of the can opening cut by the cutting blade extends at an angle toward one side in the can axial direction as it moves radially inward, thereby achieving the same excellent effects as those of the trimming tool described above when enlarging the can opening after trimming.

[0025] [Embodiment 8 of the present invention] A trimming method according to aspect 7, wherein the can has a metal substrate and an inner coating film formed on the inner surface of the substrate, and the cutting blade cuts the substrate and the inner coating film positioned at the opening to form the cut surface.

[0026] In this case, the inner coating film is more likely to be positioned at the corner (sharp portion) where the inner circumferential surface of the can opening and the cut surface are connected. More specifically, the inner coating film is more likely to be located at the tip of the sharp portion. Therefore, when the can opening is expanded after trimming, the expansion die is more likely to come into contact with the inner coating film of the sharp portion, while contact with the metal substrate exposed at the cut surface is more suppressed. Furthermore, after the expansion process begins, the die presses the opening via the inner coating film, deforming the opening. Therefore, the phenomenon of metal powder adhering to the die (build-up) can be more significantly suppressed.

[0027] [Embodiment 9 of the present invention] a can having a cylindrical peripheral wall, the peripheral wall having: a tapered portion disposed at an opening of the peripheral wall and decreasing in diameter toward one side in the can axis direction; and a curled portion disposed at the opening of the peripheral wall and connected to one end of the tapered portion in the can axis direction, the curled portion having an expanded diameter portion connected to one end of the tapered portion in the can axis direction and increasing in diameter toward one side in the can axis direction; and an outer tube portion connected to an outer end of the expanded diameter portion in the can radial direction and extending from a connection with the expanded diameter portion to the other side in the can axis direction, the outer tube portion being disposed at the other end of the outer tube portion in the can axis direction and having a cut surface facing an outer peripheral surface of the tapered portion, the cut surface extending toward one side in the can axis direction as it moves inward in the can radial direction.

[0028] According to the can of the present invention, the cut surface located at the curled portion extends radially inward and toward one side in the can axial direction, following the inclination of the outer peripheral surface of the tapered portion. This makes the cut surface less visible from the outside radially, thereby preventing the cut surface with a metallic luster from standing out more than its surroundings. Furthermore, the small gap between the outer peripheral surface of the tapered portion and the cut surface of the curled portion prevents liquids (beverages, etc.) from seeping into the curled portion through this gap. [Effects of the Invention]

[0029] The trimming tool, can manufacturing apparatus, and trimming method of the above aspects of the present invention can prevent metal powder from adhering to the mold during diameter expansion after trimming and can reduce the forming load. Furthermore, the can of the above aspects of the present invention can prevent the cut surface of the curled portion from being unnoticeable due to metallic luster. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a side view schematically showing a can manufacturing apparatus according to the present embodiment. [Figure 2] FIG. 2 is a schematic view showing a cross section taken along line II-II in FIG. [Figure 3] FIG. 3 is a side view (longitudinal cross-sectional view) showing a part of the trimming tool of this embodiment in cross section. [Figure 4] FIG. 4 is a vertical cross-sectional view that schematically shows a part (mold) of a diameter expansion tool that performs diameter expansion on the opening of the can after trimming. [Figure 5] FIG. 5 is a cross-sectional image (X-ray image) showing a part of the opening (near the curled portion) of the can of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] A can manufacturing apparatus 1, a trimming tool 40, a trimming method, and a bottle-shaped can (can) P according to one embodiment of the present invention will be described with reference to the drawings. As shown in Figures 1 and 2, the can manufacturing apparatus 1 of this embodiment is a so-called bottle necker (bottle can manufacturing apparatus) that manufactures bottle cans (product cans) P of a predetermined shape by performing multiple types of forming processes, including die processing and rotation processing, on a cylindrical can (intermediate formed can) W, which is a workpiece.

[0032] The cans W supplied as workpieces to the can manufacturing apparatus 1 are DI cans that have been subjected to DI (Drawing & Ironing) processing, printing, painting, etc. in processes upstream of the can manufacturing apparatus 1. DI cans are formed into a bottomed cylindrical shape by subjecting a disk-shaped blank punched out of an aluminum alloy plate material to a cupping process (drawing process), a DI process (drawing and ironing process), a trimming process, a printing process, a painting process, etc.

[0033] 4, the can W in this embodiment has a substrate 101 made of metal such as an aluminum alloy, an outer coating film 102 provided on the outer surface of the substrate 101, and an inner coating film 103 provided on the inner surface of the substrate 101. Note that Fig. 4 schematically shows the opening of the can W. The outer coating film 102 and the inner coating film 103 are made of a non-metallic material, specifically, for example, a resin.

[0034] The can W has a cylindrical peripheral wall (can body) and a generally disc-shaped bottom wall (can bottom). In this embodiment, the central axis of the can W is called the can axis, and the direction in which the can axis extends is called the can axial direction. In each drawing, the can axial direction corresponds to the X-axis direction. In the can axial direction, the direction from the bottom wall of the can W toward the opening of the peripheral wall (-X side) is called one side in the can axial direction, and the direction from the opening of the peripheral wall toward the bottom wall (+X side) is called the other side in the can axial direction. Note that the one side in the can axial direction (-X side) may also be called the opening side in the can axial direction or simply the opening side, and the other side in the can axial direction (+X side) may also be called the bottom side in the can axial direction or simply the bottom side.

[0035] The direction perpendicular to the can axis is called the can radial direction. The direction toward the can axis is called the inner can radial direction, and the direction away from the can axis is called the outer can radial direction. The direction around the can axis is called the can circumferential direction.

[0036] In the can manufacturing apparatus 1, a bottle necking process is performed on the opening of a bottomed, cylindrical can W, thereby forming a mouth portion and a shoulder portion (see the shape of the bottle-shaped can P in Fig. 2). The mouth portion is the smallest diameter portion of the peripheral wall of the can W. The shoulder portion is located between the mouth portion and the body portion, which is the largest diameter portion of the peripheral wall of the can W, and has a tapered shape that gradually reduces in diameter from the body portion to the mouth portion along the can axial direction.

[0037] The bottle-shaped can P produced by processing the can W by the can manufacturing apparatus 1 is filled with a beverage or other contents in a process subsequent to the can manufacturing apparatus 1, and is sealed by screwing a cap onto the mouth portion. That is, in this embodiment, the can W is a can body for the bottle-shaped can P, the opening of which is screwed onto a cap. Other configurations of the bottle-shaped can P will be described separately below.

[0038] As shown in Figures 1 and 2, the can manufacturing apparatus 1 includes an apparatus main body 4, a holding table 3, a processing table 2, a shaft portion 5, a crank mechanism 8, a drive motor 11, a table index mechanism 9, a supply wheel 10, a discharge wheel 14, a wheel index mechanism 15, and a conveying means 12.

[0039] The processing table 2 and the holding table 3 have respective central axes, i.e., table axes TA, which extend horizontally, and are arranged coaxially with each other. The processing table 2 and the holding table 3 are arranged side by side in the direction in which the table axes TA extend, and are opposed to each other.

[0040] In this embodiment, the direction in which the table axis TA extends is called the table axis direction. In each drawing, the table axis direction corresponds to the X-axis direction. Within the table axis direction, the direction from the holding table 3 to the processing table 2 (-X side) is called one side of the table axis direction, and the direction from the processing table 2 to the holding table 3 (+X side) is called the other side of the table axis direction. The table axis direction can also be referred to as the front-to-rear direction. In this case, one side of the table axis direction (-X side) corresponds to the front side, and the other side of the table axis direction (+X side) corresponds to the rear side.

[0041] The direction perpendicular to the table axis TA is called the table radial direction. Within the table radial direction, the direction approaching the table axis TA is called the inner table radial direction, and the direction away from the table axis TA is called the outer table radial direction. The direction of rotation around the table axis TA is called the table circumferential direction.

[0042] The device body 4 supports the holding table 3, the processing table 2, the shaft portion 5, the crank mechanism 8, the table index mechanism 9, the drive motor 11, the supply wheel 10, the discharge wheel 14, and the wheel index mechanism 15. The conveying means 12 extends outside the device body 4.

[0043] Although detailed illustration is omitted, the device main body 4 has, for example, a base, a frame attached to the base, and an exterior member that covers the base and the frame. The base is installed on the floor of a facility such as a factory. The frame is assembled on the base and fixed to the base with fastening members such as bolts, welding, etc. The exterior member has a housing shape and includes multiple plate-like members. Part of the exterior member is an openable door that can be opened and closed during maintenance of the components of the device, etc.

[0044] The holding table 3 is called, for example, a turntable or an index table. The holding table 3 has a circular annular shape. The holding table 3 is, for example, a large-diameter (for example, a radius of 650 mm or more) circular ring-shaped or disk-shaped table.

[0045] A plurality of chucks 7 are arranged at equal pitches along the circumferential direction of the table on the outer periphery of the surface of the holding table 3 facing one side (-X side) in the table axial direction. That is, the holding table 3 has a plurality of chucks 7 arranged side by side in the circumferential direction of the table on the outer periphery of the holding table 3. The plurality of chucks 7 hold a plurality of cans W.

[0046] Specifically, each chuck 7 holds the bottom of a can W. The can W held by the chuck 7 has its opening facing one side (-X side) in the table axial direction, facing the processing table 2. The holding table 3 is intermittently rotated in the table circumferential direction by a table index mechanism 9. That is, the holding table 3 holds a plurality of cans W and is intermittently rotated around the table axis TA.

[0047] In this embodiment, the direction in the table circumferential direction in which the holding table 3 is intermittently rotated relative to the processing table 2 is called the holding table rotation direction R1, and the opposite rotation direction is called the opposite direction to the holding table rotation direction R1 or the anti-holding table rotation direction.

[0048] The holding table rotation direction R1 is the same direction as the direction in which a plurality of processing tools 6 (described later) provided on the processing table 2 are arranged around the table in the order of processing the can W. Therefore, the holding table rotation direction R1 can be rephrased as the downstream side of the processing order for the can W (or simply the processing forward direction), and the direction opposite to the holding table rotation direction R1 (counter-holding table rotation direction) can be rephrased as the upstream side of the processing order for the can W.

[0049] The processing table 2 is called, for example, a die table. The processing table 2 has a circular annular shape. The processing table 2 is, for example, a large-diameter circular ring-shaped or disk-shaped table. The diameter dimension (outer diameter dimension) of the processing table 2 is approximately the same as the diameter dimension of the holding table 3.

[0050] The processing table 2 is supported by the device body 4 via a shaft 5. The shaft 5 is fixed to the processing table 2 and extends in the table axial direction around the table axis TA. The shaft 5 penetrates the holding table 3 in the table axial direction. The shaft 5 is movable in the table axial direction relative to the holding table 3. The shaft 5 is supported by the device body 4 so as to be slidable in the table axial direction, and the other end of the shaft 5 in the table axial direction (+X side) is connected to a connecting rod 18 of the crank mechanism 8, which will be described later.

[0051] The processing table 2 is disposed opposite to one side (-X side) in the table axial direction of the holding table 3. The processing table 2 is reciprocated by a crank mechanism 8 relative to the holding table 3 in the table axial direction.

[0052] The processing table 2 has a plurality of processing tools 6 that process each can W held by each chuck 7. The multiple processing tools 6 are arranged side by side in the table circumferential direction on the outer periphery of the processing table 2. Specifically, the multiple processing tools 6 are arranged at equal pitches along the table circumferential direction on the outer periphery of the processing table 2, and are each arranged opposite the multiple cans W held by the holding table 3 from one side in the table axial direction. The multiple processing tools 6 are of different types.

[0053] As shown in FIG. 1, the central axis (tool central axis) C of each processing tool 6 extends parallel to the table axis TA. In this embodiment, the direction in which the central axis C of the processing tool 6 extends is referred to as the axial direction. The axial direction is the same direction as the table axial direction and corresponds to the X-axis direction in each drawing. In this embodiment, one axial side corresponds to one side (-X side) in the table axial direction, and the other axial side corresponds to the other side (+X side) in the table axial direction. The axial direction can also be referred to as the front-to-rear direction. In this case, one axial side (-X side) corresponds to the front side, and the other axial side (+X side) corresponds to the rear side.

[0054] The direction perpendicular to the central axis C is called the radial direction. Of the radial directions, the direction approaching the central axis C is called the radially inner direction, and the direction away from the central axis C is called the radially outer direction. The direction going around the central axis C is called the circumferential direction.

[0055] The axial direction may be referred to as the tool axial direction to distinguish it from the table axial direction, the radial direction may be referred to as the tool radial direction to distinguish it from the table radial direction, and the circumferential direction may be referred to as the tool circumferential direction to distinguish it from the table circumferential direction.

[0056] The central axis C of the processing tool 6, the central axis of the chuck 7 facing the processing tool 6, and the can axis of the can W held by the chuck 7 are arranged coaxially with each other during processing of the can W. Each processing tool 6 faces each can W from one axial side (one side in the tool axial direction, i.e., the -X side). Processing is performed on the can W by the processing tool 6 with the central axis of the chuck 7 and the can axis of the can W aligned with the central axis C of the processing tool 6. Here, the one axial side corresponds to one side (-X side) in the can axial direction, and the other axial side corresponds to the other side (+X side) in the can axial direction. Therefore, the one axial side (-X side) may be referred to as the opening side in the can axial direction or simply as the opening side, and the other axial side (+X side) may be referred to as the bottom side in the can axial direction or simply as the bottom side.

[0057] The processing table 2 has mounting holes (not shown) that penetrate the processing table 2 in the table axis direction (X axis direction). A plurality of mounting holes are provided in the processing table 2. The plurality of mounting holes are arranged in a line in the table circumferential direction on the outer periphery of the processing table 2. A plurality (a plurality of types) of processing tools 6 are lined up in the order of processing on the can W along the holding table rotation direction R1 and attached to each mounting hole.

[0058] The multiple processing tools 6 include multiple die processing tools and multiple rotary processing tools. In this embodiment, the die processing tools and the rotary processing tools are detachably attached to multiple mounting holes in the processing table 2 in the order in which they are to be processed on the can W. Note that an oiling tool that applies oil to the portion of the can W to be processed may be detachably attached to one or more of the multiple mounting holes.

[0059] The multiple die processing tools move axially (in the can axial direction) relative to the can W, and perform various die processing such as drawing (diameter reduction processing) and diameter expansion processing on the opening of the can W. One die processing tool performs one type (predetermined) of die processing on the can W.

[0060] Specifically, the multiple die processing tools include a diameter reduction processing tool (not specifically shown) that reduces the diameter of the opening of the can W using a die, and a diameter expansion processing tool 71 that expands the diameter of the opening of the can W using a die 72, as shown in Figure 4.

[0061] Although not specifically shown, the die of the diameter reduction tool has a diameter reduction surface that gradually or stepwise reduces in diameter (the diameter dimension becomes smaller) toward one axial side (-X side). When the diameter reduction tool is used to reduce the opening of the can W (necking), at least the diameter reduction surface of the die comes into contact with the opening of the can W. A plurality of diameter reduction tools are provided at intervals from each other in the circumferential direction of the table. However, only one diameter reduction tool may be provided.

[0062] The die 72 of the expansion tool 71 has an expansion surface 73 that expands (increases in diameter) gradually or stepwise toward one axial side (-X side). When the opening of the can W is expanded by the expansion tool 71, at least the expansion surface 73 of the die 72 comes into contact with the opening of the can W. A plurality of expansion tools 71 are provided at intervals from each other in the circumferential direction of the table. Note that only one expansion tool 71 may be provided.

[0063] The multiple rotary processing tools perform various rotary processing operations such as trimming, thread forming, curling, and slot (curl crushing) on ​​the opening of the can W by rotating in the circumferential direction (around the can axis) relative to the can W. One rotary processing tool performs one type (predetermined) of rotary processing on the can W.

[0064] 3 shows a trimming tool 40, which is one of the plurality of rotary processing tools. In this embodiment, the plurality of processing tools 6 includes the trimming tool 40 and an expansion tool 71. The trimming tool 40 is disposed upstream of the expansion tool 71 in the processing order for the can W around the table axis TA. The detailed configuration of the trimming tool 40 will be described separately later.

[0065] 1, the crank mechanism 8 reciprocates the processing table 2 in the table axis direction relative to the holding table 3. The crank mechanism 8 has a drive shaft 16 to which rotation (rotational driving force) from the drive motor 11 is input, a crank shaft 17 connected to the drive shaft 16 and rotated around the axis O of the drive shaft 16 as the drive shaft 16 rotates, and a connecting rod 18 connecting the crank shaft 17 to the shaft section 5. The crank mechanism 8 converts the rotational motion around the axis O input to the drive shaft 16 from the drive motor 11 into linear motion in the table axis direction and outputs it to the shaft section 5. The drive motor 11 is, for example, an inverter motor.

[0066] The table index mechanism 9 rotates and stops (intermittently rotates) the holding table 3 in the table circumferential direction for each stroke of reciprocating movement along the table axis direction of the processing table 2. The table index mechanism 9 has a structure that intermittently rotates the holding table 3 around the table axis TA relative to the processing table 2 in accordance with the crank angle around the drive shaft 16 of the crank mechanism 8.

[0067] Therefore, the holding table 3 and the processing table 2 are repeatedly moved toward and away from each other in the table axial direction by the crank mechanism 8, and are intermittently rotated relative to each other in the table circumferential direction by the table index mechanism 9. Specifically, the processing table 2 moves toward and away from the holding table 3 in the table axial direction, and during one stroke (reciprocating movement) of this approaching and separating, the holding table 3 rotates (intermittently rotates) by a predetermined amount relative to the processing table 2 in the table circumferential direction.

[0068] Then, with each stroke of the processing table 2 and the holding table 3 moving towards or away from each other, a predetermined processing is performed on the can W held by the chuck 7 of the holding table 3 by each processing tool 6 of the processing table 2, and the holding table 3 moves the can W downstream in the processing order (in the holding table rotation direction R1) to the processing position by the next (different) processing tool 6. By repeating this operation, the can W held by the holding table 3 is processed sequentially by the multiple processing tools 6 provided on the processing table 2, and when processing by all the processing tools 6 is completed, a bottle can P having a predetermined shape is obtained.

[0069] As shown in FIG. 2, the supply wheel 10 supplies cans W to the holding table 3. The supply wheel 10 is called an in-feed wheel and is generally cylindrical. The supply wheel 10 receives cans W supplied to a chute 13 from outside the can manufacturing apparatus 1 (an earlier process than the can manufacturing apparatus 1) and delivers the cans W to the holding table 3. The supply wheel 10 has a wheel axis SA, which is its central axis, extending parallel to the table axis TA, and is supported by the apparatus main body 4. The supply wheel 10 rotates around the wheel axis SA in a wheel rotation direction R2.

[0070] The discharge wheel 14 discharges the processed cans W (bottle cans P) from the holding table 3. The discharge wheel 14 is called a discharge wheel and is generally cylindrical. The discharge wheel 14 receives the cans W (bottle cans P) that have been processed by the can manufacturing apparatus 1 from the holding table 3 and hands them over (discharges) them to the conveying means 12. The conveying means 12 conveys the bottle cans P toward the outside of the can manufacturing apparatus 1 (to a process downstream of the can manufacturing apparatus 1). The discharge wheel 14 has a wheel axis DA, which is its central axis, extending parallel to the table axis TA, and is supported by the apparatus main body 4. The discharge wheel 14 rotates around the wheel axis DA in a wheel rotation direction R3.

[0071] The supply wheel 10 has a plurality of recessed pockets 23 capable of holding the peripheral walls of cans W. The plurality of pockets 23 are arranged on the outer periphery of the supply wheel 10 at equal intervals in the circumferential direction of the wheel about the wheel axis SA. The discharge wheel 14 has a plurality of recessed pockets 24 capable of holding the peripheral walls of cans W (bottle-shaped cans P). The plurality of pockets 24 are arranged on the outer periphery of the discharge wheel 14 at equal intervals in the circumferential direction of the wheel about the wheel axis DA. Note that the pockets 23, 24 are partially omitted from illustration in FIG. 2.

[0072] These pockets 23, 24 are formed with concave curved surfaces, with cross sections perpendicular to the wheel axes SA, DA being concave arc-shaped, corresponding to the cylindrical peripheral wall of the can W. Suction holes communicating with an air suction source (not shown) are opened on the inner surfaces of the pockets 23, 24. The pockets 23, 24 can hold the can W by the air suction force of the air suction source acting on the peripheral wall of the can W through the suction holes.

[0073] The wheel index mechanism 15 intermittently rotates the supply wheel 10 and the discharge wheel 14 around the wheel axes SA and DA in synchronization with the intermittent rotation of the holding table 3 around the table axis TA.

[0074] Specifically, the supply wheel 10 and the discharge wheel 14 are intermittently rotated by the wheel index mechanism 15 in wheel rotation directions R2 and R3 (clockwise around the wheel axes SA and DA in the example of Figure 2), which are opposite to the holding table rotation direction R1 (counterclockwise around the table axis TA in the example of Figure 2).

[0075] When the supply wheel 10 rotates intermittently and the can W held in the pocket 23 of the supply wheel 10 is positioned so as to overlap the chuck 7 of the holding table 3 (directly above the chuck 7) as viewed from the table axial direction, a pushing portion (not shown) provided on the processing table 2 pushes the can W toward the other side (+X side) in the table axial direction. As a result, the can W is transferred from the pocket 23 to the chuck 7 and held by the chuck 7.

[0076] Furthermore, the can W held by the chuck 7 of the holding table 3 is transferred in the holding table rotation direction R1 with each stroke of the processing table 2, and when all processing is completed and the can W is positioned so as to overlap with the pocket 24 of the discharge wheel 14 (directly below the pocket 24) as viewed from the table axial direction, an ejection piston provided in the chuck 7 pushes out the can W (a bottle-shaped can P that has been fully processed) toward one side (the -X side) in the table axial direction. As a result, the can W (bottle-shaped can P) is transferred from the chuck 7 to the pocket 24 and held in the pocket 24.

[0077] The bottle cans P held in the pockets 24 are transferred around the wheel axis DA as the discharge wheel 14 rotates intermittently, and are then released from the pockets 24 and transferred to the conveying means 12.

[0078] The drive motor 11, crank mechanism 8, table index mechanism 9, and wheel index mechanism 15 are mechanically linked together so that they can be synchronized with one another by, for example, gears, belts, joints, etc. In other words, the rotational driving force of the drive motor 11 drives the crank mechanism 8, table index mechanism 9, and wheel index mechanism 15 in synchronization with one another.

[0079] Next, the trimming tool 40 of this embodiment will be described with reference to Fig. 3. The trimming tool 40 is a rotary tool that performs trimming on the opening (mouth portion) of the can W. Specifically, the trimming tool 40 cuts the end of one side (-X side) in the can axial direction of the opening of the can W around the entire circumference of the can, thereby forming an annular cut surface 105 whose position in the can axial direction is constant around the entire circumference of the can.

[0080] As shown in FIG. 3, the trimming tool 40 includes a tool body 41, a cutting tip 42, a tip holder 43, a cutting edge position adjuster 44, a bore guide 45, and a bearing 46.

[0081] The tool body 41 has a columnar shape centered on the central axis (tool central axis) C of the trimming tool 40 and extends in the axial direction. In this embodiment, the tool body 41 has a multi-stage columnar shape whose diameter gradually decreases toward the other axial side (+X side).

[0082] Although not shown in the figures, the tool body 41 is connected via a sprocket, a belt, etc. to a rotary machining motor attached to the machining table 2. The tool body 41 rotates around the central axis C due to the rotation of the rotary machining motor.

[0083] The tool body 41 has a recess 41a. The recess 41a is recessed radially inward from the outer circumferential surface of the tool body 41. The recess 41a also has a wall surface 41b facing the other axial side (+X side).

[0084] The cutting tip 42 is a so-called cutting insert. The cutting tip 42 is made of, for example, cemented carbide. In this embodiment, the cutting tip 42 has a polygonal plate shape, such as a triangular plate shape. The cutting tip 42 has a cutting edge 42a. That is, the trimming tool 40 has the cutting edge 42a.

[0085] The cutting edge 42a is disposed opposite from the one axial side at an end portion on one axial side (-X side) of the opening of the can W. The cutting edge 42a extends radially inward toward the one axial side. In this embodiment, the cutting edge 42a is linear.

[0086] 3, the angle β formed between the cutting edge 42a and an imaginary straight line VL perpendicular to the central axis C is, for example, 3° or more and 40° or less. The angle β is more preferably, for example, 10° or more and 30° or less, and even more preferably, for example, 10° or more and 20° or less. In this embodiment, the angle β is approximately 15°.

[0087] The tip holding part 43 holds the cutting tip 42 and is fixed to the tool body 41 by a fastening member 47 such as a bolt. Specifically, the tip holding part 43 is attached to a recess 41a of the tool body 41. The cutting tip 42 is disposed at the end of the tip holding part 43 on the other axial side (+X side). The cutting tip 42 is detachably fixed to the tip holding part 43 by a clamp screw or the like.

[0088] In this embodiment, the cutting edge position adjustment portion 44 has a male screw shape extending in the axial direction. The cutting edge position adjustment portion 44 has a male screw shaft 44a and a screw head portion 44b arranged on one axial side (-X side) of the male screw shaft 44a. The male screw shaft 44a is screwed into a female screw hole (not shown) that opens on an end face of the tip holding portion 43 facing one axial side (-X side). The screw head portion 44b contacts a wall surface 41b of the recess 41a from the other axial side (+X side).

[0089] The cutting tip 42 can be moved in the axial direction together with the tip holder 43 by adjusting the amount by which the male screw shaft 44a of the cutting edge position adjustment part 44 is screwed into the female screw hole of the tip holder 43. In this way, the cutting edge position adjustment part 44 can adjust the axial position of the cutting edge 42a with respect to the opening of the can W.

[0090] The bore guide 45 has a cylindrical shape centered on the central axis C and extends in the axial direction. The bore guide 45 is rotatably supported by the tool body 41 via a bearing 46. The bore guide 45 is disposed on the other axial side (+X side) of the cutting tip 42.

[0091] In this embodiment, the outer peripheral surface of the bore guide 45 has a tapered surface shape that extends radially inward as it approaches the other axial side (+X side). When the processing table 2 moves toward the other side (+X side) in the table axial direction toward the holding table 3, the bore guide 45 is inserted into the opening of the can W along the axial direction. At this time, the end of the bore guide 45 on one axial side (-X side) fits into the opening of the can W. In this state, the cutting edge 42a of the cutting tip 42 is brought into contact with the end of the opening of the can W on one axial side (-X side).

[0092] When the tool body 41 is rotated around the central axis C by the rotation of the rotary processing motor, the bore guide 45 that fits into the opening of the can W does not rotate, but the cutting tip 42 rotates together with the tool body 41. That is, the cutting blade 42a is rotatable around the central axis C relative to the bore guide 45. While rotating around the central axis C of the trimming tool 40, the cutting blade 42a cuts the opening of the can W and forms a cut surface 105 at the opening that faces one axial side (-X side).

[0093] Specifically, the cutting surface 105 extends radially inward and toward one axial side (-X side) in accordance with the shape of the cutting edge 42a (see FIG. 4). As shown in FIG. 3, when viewed from the radial direction, the angle formed between the cutting surface 105 and an imaginary line VL perpendicular to the central axis C is the same value as the angle β described above.

[0094] Furthermore, when the processing table 2 moves away from the holding table 3 toward one side (-X side) in the table axial direction, the diameter guide 45 is pulled out from inside the opening of the can W toward one side (-X side) in the axial direction.

[0095] Next, a method for trimming the opening of the can W using the trimming tool 40 of this embodiment will be described. The trimming method of this embodiment trims the opening of a cylindrical can W, and cuts the opening by rotating the can W and the cutting blade 42a relatively around the can axis of the can W (corresponding to around the central axis C). Specifically, the cutting blade 42a is rotated around the can axis with respect to the can W to cut the opening, and a cut surface 105 facing one side in the can axial direction (corresponding to one axial side) is formed in the opening. This cut surface 105 extends toward one side in the can axial direction as it moves inward in the can radial direction (corresponding to the radially inward direction).

[0096] Specifically, the cutting blade 42a cuts the substrate 101, the outer coating film 102, and the inner coating film 103 placed at the opening of the can W, forming the cut surface 105 having the above-mentioned inclined surface shape (see Figure 4).

[0097] Next, the bottle-shaped can (can) P of this embodiment will be described in detail. 2, the bottle-shaped can P has a cylindrical shape with a bottom, and includes a cylindrical peripheral wall (can body) and a plate-shaped bottom wall (can bottom). The bottle-shaped can P of this embodiment is manufactured by performing curling, slotting, etc. on the opening of the can W, on which the cut surface 105 has been formed by the trimming method described above.

[0098] 5 is a cross-sectional image (X-ray image) showing a part of the opening (mouth portion) of the bottle-can P. The peripheral wall of the bottle-can P has a tapered portion 110 that is disposed at the opening of the peripheral wall and that decreases in diameter toward one side (-X side) in the can axial direction, and a curled portion 120 that is disposed at the opening of the peripheral wall and connected to the end of the tapered portion 110 on one side in the can axial direction.

[0099] The curled portion 120 is connected to one end of the tapered portion 110 in the can axis direction and has an expanded diameter portion 121 that expands in diameter toward one side in the can axis direction, and an outer tube portion 122 that is connected to the outer end of the expanded diameter portion 121 in the can axis direction and extends from the connection with the expanded diameter portion 121 to the other side (+X side) in the can axis direction.

[0100] 5, in a vertical cross-sectional view of the mouth portion of the bottle-can P, the expanded diameter portion 121 has a curved shape that is convex toward one side in the can axis direction. The outer cylinder portion 122 has a substantially cylindrical shape centered on the can axis.

[0101] The outer cylinder portion 122 has a cut surface 105 located at the end of the outer cylinder portion 122 on the other side (+X side) in the can axial direction. The cut surface 105 of the outer cylinder portion 122 faces the other side in the can axial direction. More specifically, in the trimming method described above, after the cut surface 105 facing one side in the can axial direction is formed at the opening of the can W, the opening is curled, and the cut surface 105 of the bottle-shaped can P is folded back toward the can bottom.

[0102] 5, the cut surface 105 of the outer tubular portion 122 faces the outer peripheral surface of the tapered portion 110. This cut surface 105 extends toward one side (-X side) in the can axial direction as it moves inward in the can radial direction. In the illustrated example, the cut surface 105 of the outer tubular portion 122 and the outer peripheral surface of the tapered portion 110 are approximately parallel to each other. There may be a gap between the cut surface 105 of the outer tubular portion 122 and the outer peripheral surface of the tapered portion 110, or they may be in contact with each other.

[0103] In the trimming tool 40 of the present embodiment described above, the cutting edge 42a extends radially inward and toward one axial side. That is, the cutting edge 42a extends at an angle with respect to an imaginary plane extending in a direction (plane direction) perpendicular to the central axis C of the trimming tool 40 (corresponding to the can axis of the can W). Therefore, the cut surface 105 of the opening of the can W cut by the cutting edge 42a also extends radially inward and at an angle toward one axial side.

[0104] The inclination of the cut surface 105 of the can W in this manner provides the following advantageous effects when the opening of the can W is expanded by the expansion tool 71 after trimming. Specifically, as shown in FIG. 4 , the expansion die 72 is more likely to come into contact with the corner (sharp portion) where the inner circumferential surface of the opening of the can W and the cut surface 105 join, while contact with the cut surface 105 is suppressed. The metal material (base material 101) of the can W is exposed at the cut surface 105, and direct contact between the cut surface 105 and the die 72 is suppressed. This suppresses the generation of burrs and significantly reduces the buildup of metal powder adhering to the die 72. Furthermore, the reduction in the frequency of burr generation also suppresses the occurrence of thread flaws and the like caused by burrs.

[0105] Furthermore, during the diameter expansion process, the die 72 first comes into contact with the corner (sharp portion) where the can W has a thin wall thickness, making the open end of the can W more likely to deform with a small force. In other words, the open end of the can W is more likely to warp and bend. This makes it possible to reduce the forming load during the diameter expansion process. Since the forming load during the diameter expansion process can be kept small, contact between the die 72 and the cut surface 105 can be more reliably suppressed, which stably suppresses buildup and also makes it easier to thin the can W.

[0106] As described above, according to this embodiment, it is possible to prevent metal powder from adhering to the die 72 during the diameter expansion process after the trimming process, and also to reduce the molding load. In this embodiment, the "diameter expansion process" refers to a diameter expansion process performed on a workpiece when forming, for example, a bulge or a curled portion at the opening (mouth portion) of a can W that is a bottle-shaped can P.

[0107] In this embodiment, the cutting blade 42 a is rotatable around the central axis C relative to the bore guide 45 . In this case, the diameter guide 45 is fitted into the opening of the can W, and while the opening is fixed by the diameter guide 45, the cutting blade 42a is rotated around the central axis C to form the cut surface 105 at the opening. The cut surface 105 having the desired inclined surface shape can be formed with high precision and stability.

[0108] In this embodiment, as shown in FIG. 3, the angle β formed between the cutting edge 42a and an imaginary line VL perpendicular to the central axis C when viewed from the radial direction is equal to or greater than 3° and equal to or less than 40°.

[0109] If the angle β is 3° or more, contact between the die 72 and the cut surface 105 can be more stably suppressed during the diameter expansion process. An angle β of 40° or less suppresses defects caused by excessive thinning of the open end (sharp portion) of the can W. Specifically, for example, defects such as the cut shape of the cut surface 105 undulating in the circumferential direction are suppressed. From the viewpoint of further enhancing the above-mentioned effects, the angle β is more preferably 10° or more and 30° or less, and even more preferably 10° or more and 20° or less.

[0110] In this embodiment, the trimming tool 40 is provided with a cutting edge position adjustment portion 44 that can adjust the axial position of the cutting edge 42a relative to the opening of the can W. In this case, by adjusting the axial position of the cutting blade 42a, it is possible to adjust the axial position of the cut surface 105 formed at the opening of the can W. Therefore, the cutting accuracy of the opening of the can W by the cutting blade 42a can be more stably improved.

[0111] In the can manufacturing apparatus 1 of this embodiment, the trimming tool 40 is disposed upstream of the diameter expansion tool 71 in the order of processing the can W around the table axis TA. According to the can manufacturing apparatus 1 of this embodiment, after the trimming tool 40 forms the inclined cut surface 105 at the opening of the can W, the opening is subjected to diameter expansion processing by the diameter expansion processing tool 71. Therefore, the above-mentioned operational effects are stably achieved.

[0112] In addition, in the trimming method for trimming the opening of the can W described in this embodiment, the can W and the cutting blade 42a are rotated relatively around the can axis of the can W to cut the opening of the can W, and a cut surface 105 facing one side in the can axis direction is formed in this opening, and the cut surface 105 extends toward one side in the can axis direction as it moves inward in the can radial direction.

[0113] According to the trimming method of this embodiment, the cut surface 105 of the opening of the can W cut by the cutting blade 42a extends at an incline toward one side in the can axial direction as it moves inward in the can radial direction. Therefore, when the opening of the can W is enlarged after trimming, excellent effects similar to those of the trimming tool 40 described above can be obtained.

[0114] In the trimming method of this embodiment, the cutting blade 42 a cuts the substrate 101 , the outer coating film 102 , and the inner coating film 103 arranged at the opening of the can W, and forms the cut surface 105 .

[0115] In this case, the inner surface coating film 103 is likely to be disposed at the corner (sharp portion) where the inner circumferential surface of the opening of the can W and the cut surface 105 join. More specifically, the inner surface coating film 103 is likely to be located at the tip of the sharp portion. Therefore, when the opening of the can W is expanded after the trimming process, the die 72 for the expansion process (specifically, the expansion surface 73) is likely to come into contact with the inner surface coating film 103 of the sharp portion, while contact with the metal substrate 101 exposed at the cut surface 105 is more suppressed. Furthermore, after the expansion process begins, the die 72 presses the opening via the inner surface coating film 103, deforming the opening. Therefore, the phenomenon of metal powder adhering to the die 72 (build-up) can be more significantly suppressed.

[0116] In addition, in the bottle-shaped can (can) P of this embodiment, the outer tubular portion 122 of the curled portion 120 has a cut surface 105 facing the outer peripheral surface of the tapered portion 110, and this cut surface 105 extends toward one side in the can axial direction as it moves inward in the can radial direction. In other words, the cut surface 105 of the curled portion 120 extends so as to follow the slope of the outer peripheral surface of the tapered portion 110. This makes cut surface 105 less visible from the outside in the radial direction of the can, thereby preventing cut surface 105, which has a metallic luster, from standing out more than its surroundings, i.e., preventing it from standing out in an undesirable way. Also, since the gap between the outer circumferential surface of tapered portion 110 and cut surface 105 of curled portion 120 is kept small, it prevents liquid (beverage) or the like from seeping into curled portion 120 through this gap.

[0117] The present invention is not limited to the above-described embodiment, and the configuration can be changed within the scope of the present invention, as will be described below.

[0118] The trimming tool 40 may include a plurality of cutting tips 42, i.e., cutting edges 42a, spaced apart from one another in the circumferential direction about the central axis C. Accordingly, a plurality of tip holders 43 and a plurality of cutting edge position adjusters 44 may be provided in the circumferential direction about the central axis C at intervals.

[0119] The present invention may also be applied to a can manufacturing apparatus for manufacturing various types of cans other than bottle-shaped cans, a trimming tool provided in the can manufacturing apparatus, and a trimming method. Specifically, the can is not limited to the bottle-shaped can described above, but may also be, for example, a cylindrical cup-shaped body with a bottom and a peripheral wall where an opening is located, and a bottom wall. The diameter of the peripheral wall increases from the bottom wall toward the opening. That is, the diameter of the peripheral wall increases from the bottom wall toward one side in the can axial direction. This can is a so-called expanding diameter cup.

[0120] The present invention achieves the above-mentioned excellent effects by being applied to various cans (the bottle cans and the expanded diameter cups (cup bodies) described above) that are provided with a process for expanding the diameter of the opening of the can after trimming.

[0121] In the above-described embodiment, an example has been described in which the cutting blade 42a rotates around the can axis relative to the can W, thereby forming the cut surface 105 at the opening of the can W, but this is not limiting. That is, the cut surface may be formed at the opening of the can by rotating the can around the can axis relative to the cutting blade.

[0122] The present invention may be combined with the various configurations described in the above-described embodiments and modifications, and may also include additions, omissions, substitutions, and other modifications of the configurations, without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the above-described embodiments, but is limited only by the claims. [Industrial Applicability]

[0123] The trimming tool, can manufacturing apparatus, and trimming method of the present invention can prevent metal powder from adhering to the mold during diameter expansion after trimming, and can reduce the forming load. Furthermore, the can of the present invention can prevent the cut surface of the curled portion from being unnoticeable due to metallic luster. Therefore, the present invention has industrial applicability. [Explanation of symbols]

[0124] 1...can manufacturing device, 2...processing table, 3...holding table, 6...processing tool, 7...chuck, 40...trimming tool, 42a...cutting blade, 45...diameter guide, 71...expansion tool, 72...mold, 101...substrate, 103...inner surface coating, 105...cut surface, 110...tapered portion, 120...curled portion, 121...expansion portion, 122...outer cylinder portion, C...center axis (can axis), P...bottle can (can), TA...table axis, VL...imaginary line, W...can, β...angle

Claims

1. A trimming tool for trimming an opening of a cylindrical can, a cutting blade that cuts the opening while rotating around a central axis of the trimming tool and forms a cutting surface in the opening that faces one axial side; The cutting edge extends toward one axial side as it moves radially inward. Trimming tool.

2. a bore guide inserted into the opening along the axial direction; The cutting blade is rotatable around the central axis relative to the bore guide. The trimming tool according to claim 1 .

3. When viewed from the radial direction, an angle formed between a virtual line perpendicular to the central axis and the cutting edge is 3° or more and 40° or less. The trimming tool according to claim 1 or 2.

4. The can is a can body for a bottle can with a cap screwed onto the opening. The trimming tool according to claim 1 or 2.

5. the can is a cylindrical cup body with a bottom including a peripheral wall in which the opening is disposed and a bottom wall, The peripheral wall has a diameter that increases from the bottom wall toward the opening. The trimming tool according to claim 1 or 2.

6. a holding table that can be rotated intermittently around a table axis; a processing table that can be reciprocated in a table axis direction relative to the holding table, the holding table has a plurality of chucks for holding a plurality of cans; the processing table has a plurality of processing tools for processing each of the cans held by each of the chucks; The plurality of processing tools include: The trimming tool according to claim 1 or 2; and a diameter expansion tool for expanding the diameter of the opening of the can using a die, The trimming tool is disposed upstream of the diameter expansion tool in the processing order for the can around the table axis. Can manufacturing equipment.

7. A trimming method for trimming an opening of a cylindrical can, comprising: The can and the cutting blade are rotated relatively around the can axis of the can to cut the opening, and a cut surface facing one side in the can axis direction is formed in the opening. the cut surface extends toward one side in the can axial direction as it moves inward in the can radial direction; Trimming method.

8. The can is A metal substrate; an inner surface coating film provided on the inner surface of the substrate; The cutting blade cuts the substrate and the inner coating film disposed in the opening to form the cut surface. The trimming method according to claim 7.

9. A can having a cylindrical peripheral wall, The peripheral wall is a tapered portion disposed at an opening of the peripheral wall, the tapered portion decreasing in diameter toward one side in the can axial direction; a curled portion that is disposed at an opening in the peripheral wall and is connected to one end of the tapered portion in the can axial direction, The curled portion is an expanding diameter portion connected to one end of the tapered portion in the can axial direction and expanding in diameter toward the one side in the can axial direction; an outer cylinder portion connected to an outer end of the expanded diameter portion in the can radial direction and extending from a connection portion with the expanded diameter portion to the other side in the can axial direction, the outer cylinder portion is disposed at the other end of the outer cylinder portion in the can axial direction and has a cut surface facing an outer peripheral surface of the tapered portion, the cut surface extends toward one side in the can axial direction as it moves inward in the can radial direction; can.

Images