Construction machinery working tool for conveying sand and method of manufacturing the same

Abstract

To provide a long-life construction machinery working tool for conveying sand including a fluororesin-metal bonded body in which a fluororesin material and a metal material are directly bonded without using an adhesive, rivets, or the like and in which peeling between the fluororesin material and the metal material and damage or the like to the fluororesin material due to friction with sand or the like are effectively suppressed, and a method of simply and efficiently manufacturing the construction machinery working tool.SOLUTION: A construction machinery working tool for conveying sand includes a fluororesin metal bonded body provided by laminating a fluororesin plate and a metal plate on an inner surface of a metal container with the fluororesin plate as a surface, the metal plate is longer and / or wider than the fluororesin plate, a direct bonded interface in which the metal plate and the fluororesin plate are directly bonded is formed at the overlapping surface between the fluororesin plate and the metal plate, and a hemmed portion is formed by folding back an edge of the metal plate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a loading platform, a construction machinery tool such as a shovel, a bucket, and a hopper used for transporting, loading, and discharging earth and sand, etc., and a manufacturing method thereof.

Background Art

[0002] In the civil engineering and construction industry, it is essential to transport a large amount of earth and sand cargo, etc. Regarding the transportation of such earth and sand cargo, there are improvement requirements from various viewpoints. For example, although a steel plate is generally used as the loading platform of a dump truck, a loading platform made of steel is heavy. On the other hand, the total weight of a vehicle when driving on the road is limited by the Road Traffic Law. In order to transport more gravel, earth and sand, etc. at one time, it is necessary to reduce the weight of the vehicle itself.

[0003] Here, if the loading platform is made of an aluminum alloy, the weight of the vehicle can be reduced. However, the wear resistance of the aluminum alloy material is significantly lower than that of the steel material. When gravel or earth and sand are repeatedly loaded and unloaded, the wear progresses severely. Considering this wear, it is necessary to increase the thickness of the aluminum alloy plate, which not only increases the weight, but also has a problem that the slipperiness of earth and sand, etc. on the surface of the aluminum alloy plate is poor, and earth and sand cargo, etc. cannot be smoothly unloaded unless the inclination of the loading platform is made steep.

[0004] In contrast, the inventors have proposed, in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2022-049070), a loading platform for transporting earth and sand, etc., which has a fluororesin material provided on the inner surface of a steel loading platform, has a joint portion where the steel loading platform and the fluororesin material are directly joined, and when the fluororesin material is peeled off from the steel loading platform at the joint portion, the fluororesin material extends in a fibrous form from the surface of the steel loading platform.

[0005] In the loading platform for transporting earth and sand described in Patent Document 1, by means of the fluororesin material provided on the inner surface of the steel loading platform, it is possible to efficiently suppress the remaining adhered soil even compared with the loading platform having a steel plate floor structure, and it is possible to provide a loading platform for transporting earth and sand etc. that can maintain the said effect even when repeatedly transporting earth and sand etc.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the loading platform for transporting earth and sand etc. described in the above Patent Document 1, even when the fluororesin material and the steel loading platform are directly joined and firmly joined to the extent that "when the fluororesin material is peeled off from the steel loading platform at the joint, the fluororesin material extends in a fibrous form from the surface of the steel loading platform", with the increase in the usage time, problems such as damage and peeling of the fluororesin material have occurred.

[0008] In view of the problems in the prior art as described above, an object of the present invention is to provide a construction machinery working tool for transporting earth and sand having a fluororesin - metal joined body in which a fluororesin plate and a metal plate are directly joined, without using adhesives, rivet fastening, etc., and a long - life construction machinery working tool for transporting earth and sand in which peeling between the fluororesin plate and the metal plate due to rubbing of earth and sand etc. and damage to the fluororesin plate are effectively suppressed, and a simple and efficient manufacturing method thereof.

Means for Solving the Problems

[0009] In order to achieve the above object, the present inventor has conducted intensive research on the structure of the fluororesin-metal bonded body used for the construction machinery working tool for earth and sand transportation. As a result, in the fluororesin-metal bonded body in which the fluororesin plate and the metal plate are directly bonded, it has been found that using a fluororesin-metal bonded body having a hemming process part in which the end part of the metal plate is bent is effective, and thus the present invention has been achieved.

[0010] That is, the present invention is On the inner surface of a metal container, a fluororesin-metal bonded body in which a fluororesin plate and a metal plate are laminated is provided such that the fluororesin plate is on the surface, The metal plate is larger in length and / or width than the fluororesin plate, On the overlapping surface of the fluororesin plate and the metal plate, a direct bonding interface in which the metal plate and the fluororesin plate are directly bonded is formed, It has a hemming process part in which the end part of the metal plate is bent, and provides a construction machinery working tool for earth and sand transportation, characterized by the above.

[0011] Hemming process means a process of bending the end of a plate by 180° and pressing it flat. Conventionally, general hemming process aims to ensure safety, reinforcement, and improve appearance by taking the edge of a structural part.

[0012] On the other hand, in the fluororesin-metal bonded body used for the construction machinery working tool for earth and sand transportation of the present invention, a direct bonding interface in which the metal plate and the fluororesin plate are directly bonded is formed on the overlapping surface of the fluororesin plate and the metal plate. By forming a hemming process part in which the end part of the metal plate is bent, the long life of the fluororesin plate against rubbing of earth and sand is achieved.

[0013] More specifically, damage to the fluororesin plate and peeling of the fluororesin plate from the metal plate due to residual stress applied to the direct bonding interface formed on the overlapping surface of the fluororesin plate and the metal plate are suppressed by the hemming process part formed at the end of the fluororesin-metal bonded body, and the long life of the fluororesin-metal bonded body is achieved.

[0014] In addition, since the hemming portion is convex with respect to the surface of the fluororesin plate, for example, when earth and sand continuously come into contact with and slide on it, the surface of the hemming portion (metal plate) is preferentially worn, and wear of the relatively low-hardness fluororesin plate can be suppressed. Further, in the fluororesin-metal bonded body used for the construction machinery working tool for transporting earth and sand of the present invention, since the fluororesin plate and the metal plate are directly bonded at the overlapping surface, even when the hemming portion is damaged, the influence on the entire fluororesin-metal bonded body can be minimized.

[0015] Moreover, it is preferable that the construction machinery working tool for transporting earth and sand of the present invention is any one of a loading platform, a bucket, and a hopper. In these construction working tools for transporting earth and sand, where damage due to abrasion of earth and sand occurs significantly, the damage can be extremely effectively suppressed by providing the fluororesin-metal bonded body at an appropriate position of the metal base material.

[0016] In addition, in the fluororesin-metal bonded body used for the construction machinery working tool for transporting earth and sand of the present invention, it is preferable that the fluororesin plate is polytetrafluoroethylene (PTFE). Polytetrafluoroethylene has a molecular structure in which carbon atoms and fluorine atoms are linearly connected, the arrangement of atoms in the molecule is dense and symmetrical, and the charge polarization is extremely small. Polytetrafluoroethylene is particularly chemically stable among fluororesins due to this molecular structure, and has excellent characteristics such as non-stickiness, low friction, heat resistance, and chemical resistance, so that the construction machinery working tool for transporting earth and sand can have a longer service life.

[0017] Further, in the construction machinery working tool for transporting earth and sand of the present invention, it is preferable that the fluororesin-metal bonding body is provided at the corner of the metal container. Since the adhering residual soil due to transporting earth and sand is significantly formed at the corner of the container, by providing a fluororesin plate in this area, the adhering residual soil can be extremely effectively reduced. When mechanically fastening using rivets or screws, in addition to the joining to the corner being difficult compared to the joining to the flat surface, a gap is likely to occur between the surface of the metal container and the fluororesin plate. On the other hand, in the construction machinery working tool for transporting earth and sand of the present invention, since the fluororesin plate is directly joined to the inner surface of the metal container, a joint equivalent to that of the flat surface can be formed even at the corner.

[0018] Further, in the fluororesin-metal bonding body used in the construction machinery working tool for transporting earth and sand of the present invention, it is preferable that the thickness of the fluororesin plate is 0.25 to 5 mm. By setting the plate thickness of the fluororesin plate to 0.25 mm or more, deterioration of characteristics such as wear and frictional sliding resistance of the fluororesin plate during long-term durability can be suppressed, and by setting it to 5 mm or less, an increase in the weight and cost of the fluororesin-metal bonding body due to the fluororesin plate can be suppressed.

[0019] Further, in the resin-metal bonding body used in the construction machinery working tool for transporting earth and sand of the present invention, it is preferable that the fluororesin plate and the metal plate of the hemming processed portion are joined or adhered. In the fluororesin-metal bonding body, the fluororesin plate and the metal plate are integrated by the direct joint portion of the overlapping portion. However, by joining or adhering the fluororesin plate and the metal plate of the hemming processed portion, the joint state between the fluororesin plate and the metal plate becomes stronger, high reliability is imparted to the fluororesin-metal bonding body, and further long life can be achieved.

[0020] Furthermore, in the fluororesin-metal joint used in the construction machinery working tool for earth and sand transportation of the present invention, it is preferable that the fluororesin-metal joint and the metal container are welded and fastened with the bent portion of the metal plate as the welding margin. When it is necessary to attach the fluororesin-metal joint to an appropriate metal base material, the fluororesin-metal joint and the metal base material can be welded and fastened with the hemming processed portion (metal plate) as the welding margin. In the fluororesin-metal joint used in the construction machinery working tool for earth and sand transportation of the present invention, since the fluororesin plate and the metal plate are directly joined at the overlapping surface, when the hemming processed portion is used as the welding margin, it is not necessary to consider the heat influence during welding on the joint portion.

[0021] Also, the present invention is a method for manufacturing a construction machinery working tool for earth and sand transportation of the present invention, wherein a fluororesin-metal joint in which a fluororesin plate and a metal plate are laminated is installed on the inner surface of a metal container such that the fluororesin plate is on the surface, the fluororesin-metal joint has a hemming processed portion in which the end portion of the metal plate is bent, and the fluororesin-metal joint and the metal container are welded and fastened with the bent portion of the metal plate as the welding margin, and a method for manufacturing a construction machinery working tool for earth and sand transportation, which is characterized by the above, is also provided.

[0022] In the method for manufacturing a construction machinery working tool for earth and sand transportation of the present invention, since a fluororesin-metal joint having a hemming processed portion is used, the fluororesin-metal joint and the metal container can be welded and fastened with the hemming processed portion (the bent portion of the metal plate) as the welding margin. By welding and fastening the fluororesin-metal joint and the metal base material with the hemming processed portion as the welding margin, the distance between the joint portion and the welded portion of the fluororesin-metal joint and the metal base material can be ensured, and it is not necessary to consider the heat influence during welding on the joint portion.

[0023] In a fluororesin-metal bonded body, the position, shape, and size of the hemming process formed at the end of the metal plate may be appropriately adjusted according to the position, shape, and size of the direct bonding interface between the fluororesin plate and the metal plate on the overlapping surface, the shape, size, and desired mechanical properties of the fluororesin-metal bonded body, etc., but it is preferable to optimize it with respect to the residual stress applied to the direct bonding interface.

[0024] Moreover, the manufacturing method of the fluororesin-metal bonded body used in the construction machinery working tool for earth and sand transportation of the present invention is not particularly limited as long as the effects of the present invention are not impaired. However, after irradiating the surface of the metal plate with a pulsed laser in an oxidizing atmosphere to form a surface modified region, it is preferable to bring the surface modified region into contact with the fluororesin plate and raise the temperature of the overlapping surface by laser irradiation to form a direct bonding interface.

[0025] By irradiating the surface of the metal plate with a pulsed laser in an oxidizing atmosphere, an oxide cluster composed of fine oxide particles can be formed on the surface. The oxide cluster on the surface of the metal plate can promote the dissociation of the C-F bond of the fluororesin material when the resin plate is heated. Although the reason for the promotion of the dissociation is not necessarily clear, it is considered that metal oxide particles having an appropriate curvature (energy state) exhibit a so-called catalytic action. In addition, functional groups such as carboxyl groups generated by the dissociation can bond with the metal elements contained in the metal material to form a strong resin-metal direct bonding interface.

[0026] Furthermore, in the fluororesin-metal bonded body, it is preferable to bond or adhere the fluororesin plate and the metal plate at the hemming process part. Since no stress for peeling the contact surface between the fluororesin plate and the metal plate is applied at the hemming process part, by bonding or adhering the fluororesin plate and the metal plate at the hemming process part, the reliability of the fluororesin-metal bonded body can be enhanced, and the separation of the fluororesin plate from the metal plate can be effectively suppressed.

[0027] In addition, in the construction machine working tool for earth and sand transportation of the present invention, it is preferable to arrange the fluororesin-metal joint at the corner of the metal container. Earth and sand often remain at the corners of the metal container, and by providing the fluororesin-metal joint in this area, the removal of earth and sand from the metal container can be carried out efficiently and smoothly.

Advantages of the Invention

[0028] According to the construction machine working tool for earth and sand transportation of the present invention and its manufacturing method, in the construction machine working tool for earth and sand transportation having a fluororesin-metal joint in which a fluororesin material and a metal material are directly joined without using an adhesive or rivet fastening, etc., the peeling of the fluororesin material and the metal material due to rubbing of earth and sand and the damage of the fluororesin material are effectively suppressed, and a long-life construction machine working tool for earth and sand transportation and its simple and efficient manufacturing method can be provided.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0030] Hereinafter, exemplary embodiments of the construction machinery working tool for earth and sand transportation and its manufacturing method according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these only. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions may be omitted. Further, since the drawings are for conceptually explaining the present invention, the dimensions of each component shown and the ratios thereof may be different from the actual ones.

[0031] 1. Construction Machinery Working Tool for Earth and Sand Transportation An embodiment of the construction machinery working tool for earth and sand transportation will be described by taking the loading platform of a dump truck as a representative example. FIG. 1 is a schematic view showing an example of the loading platform for earth and sand transportation according to the present invention. The loading platform 2 for earth and sand transportation shown in FIG. 1 is the loading platform of a dump truck, and a fluororesin-metal bonded body 6 in which a fluororesin plate and a metal plate are laminated is provided on the inner surface of a metal container 4 so that the fluororesin plate is on the surface.

[0032] The method of fixing the fluororesin-metal bonded body 6 to the inner surface of the metal container 4 is not particularly limited as long as the effects of the present invention are not impaired, but it is preferable that the metal material of the fluororesin-metal bonded body 6 and the metal container 4 are welded.

[0033] Further, the fluororesin-metal bonded body 6 does not need to cover the entire inner surface of the metal container 4 and can be provided in a region where the adhesion of earth and sand is remarkable. For example, in the case of the loading platform of a dump truck, by providing the fluororesin-metal bonded body 6 at at least the corner portions of the metal container 4, the adhesion of earth and sand to the loading platform can be effectively suppressed.

[0034] FIG. 2 is a schematic view showing an example of the fluororesin-metal bonded body 6. FIG. 2 shows a plan view and a cross-sectional view from the fluororesin plate side. The fluororesin-metal bonded body 6 is a resin-metal bonded body in which a fluororesin plate 8 and a metal plate 10 are laminated. The metal plate 10 is larger in length and / or width than the fluororesin plate 8. A direct bonding interface 12 where the metal plate 10 and the fluororesin plate 8 are directly bonded is formed on the overlapping surface of the fluororesin plate 8 and the metal plate 10, and it has a hemming portion 14 where the end portion of the metal plate 10 is bent.

[0035] In the plan view of FIG. 2, the position of the direct bonding interface 12 is indicated by a dotted line. The position, shape, and size of the direct bonding interface 12 are not particularly limited as long as the effects of the present invention are not impaired, and may be appropriately adjusted according to the types, shapes, and sizes of the fluororesin plate 8 and the metal plate 10, the usage mode of the fluororesin-metal bonded body 6, etc. For example, when obtaining a rectangular fluororesin-metal bonded body 6, an appropriate number of linear direct bonding interfaces 12 parallel to the long side and / or the short side may be formed.

[0036] Further, in the fluororesin-metal bonded body 6, since the vicinity of both ends of the direct bonding interface 12 is constrained by the hemming portion 14, even when shear residual stress is applied to the direct bonding interface 12, damage to the fluororesin plate 8 and separation of the fluororesin plate 8 and the metal plate 10 are extremely effectively suppressed. The position, shape, and size of the hemming portion 14 may be appropriately adjusted according to the shape and size of the direct bonding interface 12 and the fluororesin-metal bonded body 6, etc. As shown in FIG. 2, when a linear direct bonding interface 12 is formed, it is preferable to design so that both ends of the direct bonding interface 12 are sufficiently constrained.

[0037] The material of the fluororesin plate 8 is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known fluororesins can be used. However, it is more preferable that the fluororesin plate 8 is polytetrafluoroethylene. By using polytetrafluoroethylene as the fluororesin plate 8, good chemical resistance, abrasion resistance, flame retardancy, water and oil repellency, etc. can be imparted to the fluororesin-metal bonded body 6, and the loading platform 2 for earth and sand transportation can be suitably used as various construction machinery working tools for earth and sand transportation.

[0038] The thickness of the fluororesin plate 8 is preferably 0.25 to 5 mm. By setting the thickness of the fluororesin plate 8 to 0.25 mm or more, it is possible to suppress deterioration of characteristics such as wear and frictional sliding resistance of the fluororesin plate 8 during long-term durability. By setting it to 5 mm or less, it is possible to suppress an increase in the weight and cost of the fluororesin-metal bonded body 6 due to the fluororesin plate 8. Here, the thickness of the fluororesin plate 8 is more preferably 0.5 to 3 mm, and most preferably 0.75 to 2 mm.

[0039] The material of the metal plate 10 is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known metals can be used. However, it is preferably any one of an aluminum material, an aluminum alloy material, a titanium material, a titanium alloy material, and a steel material. The metal plate 10 made of these metals and the fluororesin plate 8 can form a high-strength direct bonding interface 12. In addition, by using an aluminum material and an aluminum alloy material, a relatively inexpensive and lightweight fluororesin-metal bonded body 6 can be realized. By using a titanium material and a titanium alloy material, a lightweight fluororesin-metal bonded body 6 with excellent corrosion resistance can be realized. By using a steel material, an inexpensive fluororesin-metal bonded body 6 with excellent mechanical properties can be realized.

[0040] Also, the shape and size of the fluororesin plate 8 and the metal plate 10 are not particularly limited as long as the effects of the present invention are not impaired. However, since it is necessary to form a hemming portion 14 by folding back the end portion of the metal plate 10, the metal plate 10 before hemming is larger in width and / or length than the fluororesin plate 8.

[0041] Figure 3 shows a schematic cross-sectional view of the fluororesin-metal bonded body 6 when the fluororesin plate 8 and the metal plate 10 are joined or adhered in the hemming portion 14. In the hemming portion 14, a joining or adhesion interface 16 is formed between the fluororesin plate 8 and the metal plate 10. In the hemming portion 14, since stress in the direction of peeling the fluororesin plate 8 and the metal plate 10 is not applied, the fluororesin plate 8 and the metal plate 10 can be firmly joined or adhered. Here, the method of joining or adhering the fluororesin plate 8 and the metal plate 10 is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known joining methods or adhesion methods can be used. For example, the joining methods described in JP-A-2018-103548, JP-A-2019-123153, and International Publication No. 2021 / 230025 can be preferably used.

[0042] When the fluororesin plate 8 and the metal plate 10 are joined or adhered only in the hemming portion 14 without forming a direct joining interface 12 in which the metal plate 10 and the fluororesin plate 8 are directly joined on the overlapping surface of the fluororesin plate 8 and the metal plate 10, the fluororesin plate 8 and the metal plate 10 cannot be sufficiently adhered and fixed. As a result, damage to the fluororesin plate 8, separation between the fluororesin plate 8 and the metal plate 10, etc. are likely to occur, and the long life of the fluororesin-metal bonded body 6 and the loading platform 2 for earth and sand transportation cannot be achieved.

[0043] 2. Method for manufacturing a construction machine working tool for earth and sand transportation The method for manufacturing a construction machine working tool for earth and sand transportation according to the present invention will be described by taking the case of manufacturing the loading platform 2 for earth and sand transportation as a representative example.

[0044] On the inner surface of the metal container 4, a fluororesin-metal bonded body 6 in which the fluororesin plate 8 and the metal plate 10 are laminated is installed so that the fluororesin plate 8 is on the surface. Since the fluororesin-metal bonded body 6 has a hemming portion 14 in which the end portion of the metal plate 10 is bent, by welding and fastening the fluororesin-metal bonded body 6 and the metal container 4 using the bent portion of the metal plate 10 as a welding allowance, the loading platform 2 for earth and sand transportation can be obtained.

[0045] Since the fluororesin-metal bonded body 6 having the hemming portion 14 is used, the fluororesin-metal bonded body 6 and the metal container 4 can be welded and fastened with the hemming portion 14 (the bent portion of the metal plate) serving as the welding margin. By welding and fastening the fluororesin-metal bonded body 6 and the metal base material with the hemming portion 14 serving as the welding margin, the distance between the joint portion and the welded portion of the fluororesin-metal bonded body 6 and the metal base material can be ensured, and it is not necessary to consider the thermal influence during welding on the joint portion.

[0046] Also, the location where the fluororesin-metal bonded body 6 is disposed is not particularly limited as long as the effects of the present invention are not impaired, but it is preferable to dispose the fluororesin-metal bonded body 6 at the corner portion of the metal container 4. Sediment often remains at the corner portion of the metal container 4, and by providing the fluororesin-metal bonded body 6 in this region, the removal of sediment from the metal container 4 can be performed efficiently and smoothly.

[0047] FIG. 4 is a process diagram for obtaining the fluororesin-metal bonded body 6 used for the sediment transport bed 2. The manufacturing method of the fluororesin-metal bonded body 6 includes a first step (S01) of laminating the fluororesin plate 8 and the metal plate 10 to form a superposed surface, a second step (S02) of forming a direct bonding interface 12 between the fluororesin plate 8 and the metal plate 10 on the superposed surface, and a third step (S03) of performing hemming on the end portion of the metal plate 10. Further, as an optional step, a fourth step (S04) of joining or adhering the fluororesin plate 8 and the metal plate 10 of the hemming portion 14 can be performed. Hereinafter, each step will be described in detail.

[0048] (1) First step (S01: Superposed surface forming step) The first step (S01) is a step of superposing the fluororesin plate 8 and the metal plate 10 to form a superposed surface in order to form the direct bonding interface 12 in the second step (S02). Considering the hemming in the third step (S03), it is necessary to adjust the positions of the fluororesin plate 8 and the metal plate 10 so that the end portion of the metal plate 10 is outside the fluororesin plate 8.

[0049] Further, for example, in the second step (S02), when the superposition surface is heated by laser irradiation to form the direct bonding interface 12, as a pretreatment for the first step (S01), it is preferable to irradiate the surface of the metal plate 10 with a pulsed laser in an oxidizing atmosphere to form a surface modification region.

[0050] The laser used for the pretreatment is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known lasers can be used. For example, a semiconductor laser that can efficiently heat the metal plate 10 can be preferably used. The irradiation energy of one pulse of the pulsed laser is preferably 0.2 to 1.0 mj. By setting the irradiation energy of one pulse of the pulsed laser to 0.2 to 1.0 mj, metal oxide particles having a particle size of 5 to 500 nm are continuously joined in the irradiation region to form a metal oxide particle cluster, and the maximum height (Sz) of the surface of the metal oxide particle cluster can be set to 50 nm to 3 μm.

[0051] Further, in a state where the fluororesin plate 8 and the metal plate 10 are overlapped, by bringing a heat-resistant glass plate or the like into contact with the surface of one or both of the materials to be joined to perform overall restraint, the materials to be joined can be brought into closer contact with each other, and displacement of the bonding interface during laser irradiation in the second step (S02) can be suppressed. Note that it is preferable to use a heat-resistant glass having excellent laser transmissivity.

[0052] The material of the fluororesin plate 8 is not particularly limited as long as the effects of the present invention are not impaired, and conventionally known fluororesins can be used. Examples of such fluororesins include polytetrafluoroethylene (PTFE, melting point: 327°C), polychlorotrifluoroethylene (PCTFE, melting point: 220°C), polyvinylidene fluoride (PVDF, melting point: 151 - 178°C), polyvinyl fluoride (PVF, melting point 203°C), tetrafluoroethylene - hexafluoropropylene copolymer (FEP, melting point: 250 - 275°C), tetrafluoroethylene - perfluoroalkyl vinyl ether copolymer (PFA, melting point: 302 - 310°C), tetrafluoroethylene - ethylene copolymer (ETFE, melting point: 218 - 270°C), tetrafluoroethylene - perfluorodioxole copolymer (TFE / PDD), chlorotrifluoroethylene - ethylene copolymer (ECTFE, melting point: 245°C), etc. For example, by using the bonding method described in Patent Document 1 above, the fluororesin plate 8 and the metal plate 10 can be directly bonded, and a direct bonding interface 12 excellent in high - temperature strength can be obtained without using an adhesive. Therefore, it is preferable to use polytetrafluoroethylene (PTFE, melting point: 327°C) with a high melting point.

[0053] The metal plate 10 used as the material to be bonded is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known metal materials can be used. For example, in addition to various steel materials, stainless steel, titanium, titanium alloy, aluminum, aluminum alloy, magnesium, magnesium alloy, copper, copper alloy, etc. can be used. From the viewpoint of specific strength, it is preferable to use aluminum, aluminum alloy, titanium, and titanium alloy. From the viewpoints of corrosion resistance, etc., it is preferable to use stainless steel, titanium, and titanium alloy. Also, from the viewpoints of price and mechanical properties, it is preferable to use steel materials.

[0054] (2) Second step (S02: Direct bonding interface formation step) The second step (S02) is a step for forming the direct bonding interface 12 by raising the temperature of the overlapping surface by laser irradiation.

[0055] In the second step (S02), when the fluororesin plate 8 is transparent, it is preferable to irradiate the laser from the side of the fluororesin plate 8, and when the fluororesin plate 8 is opaque, it is preferable to irradiate the laser from the side of the metal plate 10. By irradiating the laser from the side of the fluororesin plate 8 when the fluororesin plate 8 is transparent and irradiating the laser from the side of the metal plate 10 when the fluororesin plate 8 is opaque, the temperature of the joint interface can be efficiently increased. Further, by irradiating the laser from the side of the metal plate 10, it can be used as a joint material regardless of the type of the fluororesin plate 8. Furthermore, by heating from the side of the metal plate 10, a space can be provided on the side of the fluororesin plate 8, and pressure can be applied from the surface of the fluororesin plate 8 as necessary.

[0056] In the second step (S02), it is preferable to apply a pressure of 5 MPa or more to the joint interface. By applying a pressure of 5 MPa or more to the joint interface, the fluororesin plate 8 and the metal plate 10 can be brought into close contact with each other, and a strong direct joint interface 12 can be obtained. In addition, even when bubbles or the like are formed in the joint portion as the temperature rises, the bubbles can be discharged to the outside of the system.

[0057] Further, by adding a pressing step, the direct joint interface 12 can be homogenized, and the variation in quality can be reduced. Due to the pressing, for example, since the softened fluororesin plate 8 spreads beyond the range of the heat affected zone of the metal plate 10, the direct joint interface 12 between the metal plate 10 and the fluororesin plate 8 can be expanded.

[0058] When pressing the joint interface, in the first step (S01), by bringing a heat-resistant glass plate or the like into contact with the surface of one or both of the joint materials and restraining the whole surface, the joint interface can be more easily pressed.

[0059] Regarding the process parameters related to laser irradiation such as laser output, scanning speed, and focal length, they may be appropriately selected according to the type and size of the joint material, the area of the joint interface, and the mechanical properties required for the fluororesin-metal joint 6.

[0060] (3) Third Process (S03: Hemming Process) The third process (S03) is a process for performing hemming on the end portion of the metal plate 10. Although shear residual stress is inevitably generated at the direct bonding interface 12 formed in the second process (S02), by forming a hemming portion at the end of the fluororesin-metal bonded body 6, the shear deformation of the direct bonding interface 12 can be extremely effectively suppressed.

[0061] The position, shape, and size of the hemming portion 14 formed at the end of the metal plate 10 may be appropriately adjusted according to the position, shape, and size of the direct bonding interface 12 between the fluororesin plate 8 and the metal plate 10 on the overlapping surface, the shape, size, and desired mechanical properties of the fluororesin-metal bonded body 6, etc., but it is preferable to optimize it with respect to the residual stress applied to the direct bonding interface 12.

[0062] Also, the method and processing conditions of the hemming process are not particularly limited as long as the effects of the present invention are not impaired, and conventionally known hemming methods and processing conditions can be used. For example, it is preferable to perform hemming using an appropriate roller hemming device.

[0063] (4) Hemming Portion Bonding Process The hemming portion bonding process is an optional process and is a process for bonding or adhering the fluororesin plate 8 and the metal plate 10 of the hemming portion 14.

[0064] Since stress for peeling the contact surface between the fluororesin plate 8 and the metal plate 10 is not applied at the hemming portion 14, by bonding or adhering the fluororesin plate 8 and the metal plate 10 at the hemming portion 14, the reliability of the fluororesin-metal bonded body 6 can be enhanced, and separation of the fluororesin plate 8 from the metal plate 10 can be effectively suppressed.

[0065] The method of joining or adhering the fluororesin plate 8 and the metal plate 10 is not particularly limited as long as the effects of the present invention are not impaired, and various conventionally known joining methods or adhering methods can be used. For example, the joining methods described in JP-A-2018-103548, JP-A-2019-123153, and WO 2021 / 230025 can be preferably used.

[0066] As described above, the representative embodiments of the present invention have been described. However, the present invention is not limited to these, and various design changes are possible, and all of these design changes are included in the technical scope of the present invention.

Example

[0067] 《Example》 (1) Production of fluororesin-metal bonded body Laser irradiation was performed on the surface of a 1.0 mm × 100 mm × 1000 mm stainless steel (SUH409L) plate in the atmosphere to form a surface-modified region (pre-treatment in the first step). An YLP pulsed laser manufactured by IPG was used as the laser, and the laser irradiation conditions were an average output of 50 W (energy of one pulse: 1 mJ), a focus diameter of 59 μm, and a scanning speed of 15000588.5 μm / s. In the surface-modified region, modification was performed at pitches of 90 μm (X direction: width direction of the plate) and 250 μm (Y direction: length direction of the plate) over the entire surface of the stainless steel plate. In addition, in the width direction of the plate, for the purpose of suppressing partial peeling of the resin material and the metal material during the production process of the resin-metal bonded body, a range of 10 mm from the end (region 8 in the plan view of FIG. 1) was further modified at pitches of 30 μm (X direction: width direction of the plate) and 70 μm (Y direction: length direction of the plate).

[0068] Next, the surface of the stainless steel plate on which the surface-modified region was formed was brought into contact with the surface of the fluororesin plate to form a superposed surface (first step). The fluororesin plate was a 1.0 mm × 90 mm × 1000 mm polytetrafluoroethylene (PTFE) plate. By aligning the width centers of the stainless steel plate and the fluororesin plate and superposing them, both ends of the width of the fluororesin plate protruded 5.0 mm outward from the stainless steel plate.

[0069] Next, a laser was irradiated from the stainless steel plate side to raise the temperature of the joint interface having a surface-modified region, and a direct joint interface between the stainless steel plate and the fluororesin plate was formed to obtain a resin-metal bonded body (second step). In the second step, a k8w semiconductor laser manufactured by Laserline was used, and a zoom homogenizer was used in the optical system to form a 9 mm × 100 mm line laser, which was scanned at an output of 8000 w and a scanning speed of 9 mm / s for 1000 mm. Also, in the second step, a pressure of about 15 MPa was applied to the joint interface.

[0070] Next, the stainless steel plate outside the end of the fluororesin plate was bent 180° toward the fluororesin plate side and hemming was performed (third step). An external view photograph of the obtained fluororesin-metal bonded body (actual fluororesin-metal bonded body) is shown in Fig. 5.

[0071] (2) Manufacture of a loading platform for earth and sand transportation The obtained fluororesin-metal bonded body was placed at the corner of the loading platform (metal container) of the dump truck shown in Fig. 1. Specifically, the stainless steel of the hemming portion of the fluororesin-metal bonded body and the surface of the loading platform were welded to obtain a construction machine working tool for earth and sand transportation of the present invention.

[0072] <<Comparative Example>> A fluororesin-metal bonded body (comparative fluororesin-metal bonded body) was obtained in the same manner as in the example except that hemming was not performed on the stainless steel plate outside the end of the fluororesin plate. Also, a construction machine working tool for earth and sand transportation, which is a comparative example of the present invention, was obtained in the same manner as in the example except that the end of the stainless steel plate and the surface of the loading platform were welded.

[0073] [Evaluation] Assuming a case where the fluororesin-metal bonded body is provided inside the loading platform of a dump truck, the durability of the fluororesin plate that slides against the loaded material was evaluated for the fluororesin-metal bonded body before attachment to the loading platform.

[0074] Assume that the maximum load is applied to the surface of the fluororesin plate when unloading starts from the loaded state. For a general 10-ton dump truck, the weight of its own weight per unit area of the inner surface height of 53 cm on the loading platform (when the unit volume weight during loading is 2.0 tons / m 3 In the case of, the weight of its own weight (2000 kg × 0.53 × test installation area) is applied. A load material with a standard volume (thickness 70 mm) and a weight compensation weight (iron piece) were placed on it and slid in the load material bin to observe the change of the fluororesin plate.

[0075] Here, assume that the dump unloading is 2.5 times a day and the operation of the dump truck is 300 days a year. The number of load cycles due to the rubbing of the load material is 2.5 times / day × 300 days / year = 750 times / year. The reference value with a nominal wear life of 5 years is 750 times / year × 5 years = 3750 times (1875 reciprocations). Therefore, the maximum number of tests was set to 2000 reciprocations.

[0076] Figure 6 shows an external photo of the device used in the test. A roller compactor (Pavement Survey & Test Method Handbook B002·6) was used for the test device. With the roller part fixed to the support by a chain and removed, a bin (load material bin) for applying the load material to the sample surface was fixed in the central part.

[0077] For the load material, concrete waste was crushed by a crusher, and the steel bars and crushed pieces with a particle size of 45 mm or more were removed. The load material was classified by particle size (37.5 mm or more, 22.4 - 37.5 mm, 13.2 - 22.4 mm, 13.2 mm or less). For those with different particle sizes mixed, all were filled without compaction. First, the largest particle size (for example, 40 mm or more) was arranged as evenly as possible under the load material bin, and the gaps were filled sequentially (if the largest is 40 mm or more, it was filled with 40 - 25 mm and then the gap was filled with 25 - 13 mm), and finally, the particle size of 13 mm or less was adjusted to a predetermined height (30 mm below the upper end of the load bin).

[0078] The weight of the load material packed by the above work was calculated (measured by the weight reduced from the prepared load material), and the insufficient part was adjusted with a weight (iron piece).

[0079] Next, the OFF counter of the roller compactor was set to 2000 times and it was started. At this time, if it was determined that the balance of the loaded material was damaged after startup and the rubbing load changed significantly, the loading state was corrected appropriately each time. After the test, the state of the fluororesin plate was visually inspected to evaluate the durability of the fluororesin-metal joint. When the fluororesin plate peeled off and the surface of the stainless steel plate was exposed, the test was terminated at that point. The test was carried out on three test fluororesin-metal joints and three comparative fluororesin-metal joints each.

[0080] Photographs of the appearance of the test fluororesin-metal joints and the comparative fluororesin-metal joints after the test are shown in Fig. 7. For all the test specimens of the test fluororesin-metal joints, no peeling of the fluororesin or significant damage was observed after 2000 reciprocations. On the other hand, for the comparative fluororesin-metal joints, there was a test specimen in which the fluororesin plate peeled off significantly after 1353 reciprocations of sliding. Also, for the other test specimens, although the fluororesin plate did not peel off after 2000 reciprocations of sliding, a large number of deep streak-like grooves were formed, indicating that the damage was greater compared to the test fluororesin-metal joints.

[0081] Fig. 8 shows the change over time of the surface of the fluororesin plate of the test fluororesin-metal joints with an increase in the number of sliding times. Although the fine scratches on the surface of the fluororesin plate increased somewhat with an increase in the number of sliding times, no significant damage or the like was formed at all, indicating that the test fluororesin-metal joints have extremely good durability.

[0082] From the above results, it was confirmed that damage to the fluororesin plate, peeling of the fluororesin plate from the metal plate, etc., which are caused by the residual stress applied to the fluororesin-metal direct bonding interface formed on the overlapping surface of the fluororesin plate and the metal plate, are suppressed by the hemming process part formed at the end of the fluororesin-metal joint, and the fluororesin-metal joint can have a longer life. Also, since the hemming process part is convex compared to the surface of the fluororesin plate, it can be seen that when earth and sand continuously come into contact and slide, wear of the relatively soft fluororesin plate can be suppressed.

Explanation of reference numerals

[0083] 2 ··· Loading platform for transporting earth and sand 4 ··· Metal container 6 ··· Fluororesin-metal bonding body 8 ··· Fluororesin plate 10 ··· Metal plate 12 ··· Direct bonding interface 14 ··· Hemming processed part 16 ··· Adhesive interface

Claims

1. A fluororesin-metal bonded body in which a fluororesin plate and a metal plate are laminated is provided on the inner surface of a metal container so that the fluororesin plate is on the surface, the metal plate is larger in length and / or width than the fluororesin plate, a direct bonding interface where the metal plate and the fluororesin plate are directly bonded is formed on the overlapping surface of the fluororesin plate and the metal plate, having a hemming process part in which the end part of the metal plate is bent, A construction machinery working tool for transporting earth and sand, characterized by the above.

2. It is any one of a loading platform, a bucket, and a hopper, The construction machinery working tool for transporting earth and sand according to Claim 1, characterized by the above.

3. The fluororesin plate is polytetrafluoroethylene, The construction machinery working tool for transporting earth and sand according to Claim 1 or 2, characterized by the above.

4. The fluororesin-metal bonded body is provided at the corner part of the metal container, The construction machinery working tool for transporting earth and sand according to Claim 1 or 2, characterized by the above.

5. The thickness of the fluororesin plate is 0.25 to 5 mm, The construction machinery working tool for transporting earth and sand according to Claim 1 or 2, characterized by the above.

6. The fluororesin plate and the metal plate of the hemming process part are joined or adhered, The construction machinery working tool for transporting earth and sand according to Claim 1 or 2, characterized by the above.

7. Using the bent part of the metal plate as a welding substitute, the fluororesin-metal bonded body and the metal container are welded and fastened, The construction machinery working tool for transporting earth and sand according to Claim 1 or 2, characterized by the above.

8. A manufacturing method of the construction machinery working tool for transporting earth and sand according to Claim 1 or 2, A fluororesin-metal bonded body in which a fluororesin plate and a metal plate are laminated is installed on the inner surface of a metal container so that the fluororesin plate is on the surface, The fluororesin-metal bonded body has a hemming process part in which the end part of the metal plate is bent, Using the bent part of the metal plate as a welding substitute, the fluororesin-metal bonded body and the metal container are welded and fastened, A manufacturing method of a construction machinery working tool for transporting earth and sand, characterized by the above.

9. Arranging the fluororesin-metal bonded body at the corner part of the metal container, The manufacturing method of the construction machinery working tool for transporting earth and sand according to Claim 8, characterized by the above.

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