Protective material

Abstract

To provide a protective member covering and protecting at least a part of an object space which has little restriction in materials composing a member body molded into a shape of the protective member, whose configuration is simplified, and which is easy to secure a sufficient heat radiation function and an electromagnetic wave shield function.SOLUTION: A protective member includes a member body. The member body includes a wall part covering at least a part of an object space and is configured by forming a spray coating by thermal spraying on at least an inner surface being a surface on the object space side of the wall part of a base material molded into the shape of a casing, a case, a housing, a pipe or a cover or an outer surface opposite the inner surface of the wall part. The spray coating contains a metallic material.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a protective member that covers and protects at least a part of a target space.

Background Art

[0002] Protective members such as a housing, a case, a casing, a pipe, or a cover that covers and protects at least a part of a target space are conventionally known. In the target space, for example, electronic components that are easily affected by electromagnetic waves and have a large amount of heat generation, and motors and battery units that themselves emit electromagnetic waves are arranged as objects.

[0003] In such a case, it is desirable that the protective member has a function of blocking electromagnetic waves (electromagnetic shielding function) by the material itself forming it and a function of releasing heat from the target space side to the space on the opposite side sandwiching the target space and the protective member (heat dissipation function). As typical materials that satisfy such a demand, metal materials such as iron and copper can be considered, but metal materials have a problem that the specific gravity is large and it is difficult to reduce the weight of the protective member.

[0004] To improve this problem, a protective member is known that includes a member body formed into the shape of a housing, a case, a casing, a pipe, or a cover, and a metal plate is embedded in the member body or a metal mesh is laid on the surface of the member body (for example, see Patent Document 1).

[0005] The protective member in the above document has a great merit in that an electromagnetic shielding function and a heat dissipation function can be imparted by a metal plate or a metal mesh regardless of the type of the material constituting the member body.

[0006] However, a space and members for positioning and fixing a metal plate or a metal mesh formed separately from the member body are separately required, and the configuration becomes complicated.

[0007] Furthermore, in order to provide sufficient heat dissipation to the protective material, it is necessary to form the metal plate or metal mesh into a shape with a large surface area, but it can be difficult to ensure this requirement in the space surrounding heat-generating elements such as electronic components.

[0008] On the other hand, simply laying a metal mesh may not provide sufficient electromagnetic shielding to the protective material. Furthermore, in the case of metal plates, a certain thickness is required, which necessitates a large burial space, making it difficult to meet this requirement in some locations.

[0009] In other words, in some cases, a metal plate or metal mesh formed separately from the main component may not be able to adequately ensure electromagnetic shielding or heat dissipation functions. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2009-83599 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The objective is to provide a protective member that covers and protects at least a portion of a target space, has fewer constraints on the material constituting the member body formed into the shape of the protective member, has a simplified structure, and easily ensures sufficient heat dissipation and electromagnetic wave shielding functions. [Means for solving the problem]

[0012] To solve the above problems, a protective member for protecting a target space is provided, comprising a member body, the member body including a wall portion that covers at least a part of the target space, and formed by forming a thermal spray coating by thermal spraying on at least one of the inner surface of the wall portion that faces the target space or the outer surface that is opposite to the inner surface of the wall portion, the thermal spray coating containing a metal material. Ta It is characterized by the following:

[0013] The thermal spray coating may be formed continuously over the range from the inner surface to the outer surface of the member body, thereby configuring it to release heat from the target space to the outside.

[0014] The thermal spray coating may contain a conductive metal material.

[0015] The thermal spray coating may contain a ferroelectric material, a high-permeability material, or a material that causes loss of conductivity.

[0016] The thermal spray coating may contain a resin material or a ceramic material.

[0017] The member body has a plurality of divided pieces, and at least a part of the base material is formed by joining adjacent divided pieces together, and at least a part of the joining portion which is the part of the divided piece that is joined to another divided piece, A thermal spray coating is formed that is continuous with the thermal spray coating on the inner surface and extends to the outer surface, or a thermal spray coating is formed that is continuous with the thermal spray coating on the outer surface and extends to the inner surface. A thermal spray coating may be formed.

[0018] Each of the two joining portions that are joined together may have a joining surface formed on it that is in surface contact with the other, and the thermal spray coating may be formed on at least one of the two joining surfaces.

[0019] The aforementioned joining surface may be formed flat.

[0020] The member body has a plurality of divided pieces, and at least a part of the base material is formed by joining adjacent divided pieces. Bolt insertion holes for fastening and fixing both are formed in each of the connected divided pieces. The thermal spray coating is formed on the inner peripheral surface of each insertion hole. The thermal spray coatings formed on the inner peripheral surfaces of two insertion holes through which the same bolt is inserted are connected and continuous, and one of Thermal spraying the coatings is formed in a range reaching the outer surface to while the other Thermal spraying coating may be formed in a range reaching the inner surface.

Advantages of the Invention

[0021] Since the member body integrally has a thermal spray coating on its inner surface or outer surface side, it becomes easy to ensure an electromagnetic wave shielding function and a heat dissipation function without complicating its structure. Also, generally, since thermal spraying is possible for various types of materials, there are few restrictions on the materials that can be adopted for the member body.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view for explaining the configuration of a plasma spraying apparatus for spraying a thermal spraying material onto a base material. [Figure 2] It is a cross-sectional view of a case applied to the present invention. [Figure 3] It is a cross-sectional view showing the configuration of a modified example of the case shown in FIG. 2. [Figure 4] It is a cross-sectional view showing the configuration of a modified example of the case shown in FIG. 2. [Figure 5] It is a cross-sectional view of a case according to another embodiment of the present invention. [Figure 6] It is an enlarged view of a joint portion of the case in FIG. 5. [Figure 7] It is a cross-sectional view of a case according to another embodiment of the present invention. [Figure 8] It is an enlarged view of a joint portion of the case in FIG. 7.

Embodiments for Carrying Out the Invention

[0023] The protective member to which the present invention is applied is primarily composed of a member body molded into the shape of a housing, case, pipe, or cover that covers at least a portion of the target space. The member body has a wall portion that covers part or all of the target space and is formed by thermal spraying a thermal spray material onto at least one of the surface of the wall portion facing the target space (inner surface) or the surface opposite to the inner surface (outer surface) of the wall portion, which is formed in the same shape as the member body, to form a thermal spray coating.

[0024] Any material that can be thermally sprayed can be used as the base material, and it is desirable to select one that is lightweight and has high strength. Specifically, various materials such as resin materials, glass materials, ceramic materials, wood, paper materials, or composites thereof can be selected. The strength of resin materials may be improved by using fibrous materials such as carbon fibers or glass fibers. Specifically, CFRP and GFRP are envisioned as resin materials, but the material is not limited to these.

[0025] The thermal spray material (thermal spray coating) contains at least a metallic material (preferably a conductive metallic material, a ferroelectric material, or a high-permeability material), and more specifically, is composed of a mixture of a base material and an additive. In the thermal spray coating after spraying, the additive is dispersed in the base material and is located in countless positions. In other words, the additive functions as a filler material.

[0026] The additives are made in granular form. Furthermore, the additives consist of one or more materials selected according to the functions required of the protective component. These functions broadly include electromagnetic shielding and heat dissipation, as well as heat resistance (fire resistance), weather resistance (specifically protection from ultraviolet rays), chemical resistance, and antibacterial properties.

[0027] To achieve electromagnetic shielding functionality, at least two methods are possible: a means to reflect radio waves (reflection means) and a means to absorb radio waves (absorption means).

[0028] In the reflective method, radio waves are reflected by forming a network of conductive metals within the thermal spray coating. In the absorbing method, radio waves are absorbed by thermal energy conversion (Joule heating) by including ferroelectric materials, high permeability materials, or conductive loss materials as additives.

[0029] Conductive metals can include various conductive metals such as aluminum (Al), copper (Cu), zinc (Zn), or composite materials thereof. Examples of high permeability materials include Sendust (Fe-Si-Al alloy), ferrite, amorphous alloys, or composite materials thereof.

[0030] Typical ferroelectric materials include barium titanate (BaTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), or composite materials thereof. Examples of conductive loss materials include carbon-based materials.

[0031] Furthermore, when heat resistance is important, alumina (Al2O3), zirconia (ZrO2), or composite materials thereof are used; when heat dissipation is important, magnesium oxide (MgO), silicon carbide (SiC), alumina (Al2O3), aluminum nitride (AlN), or composite materials thereof are used; when weather resistance due to ultraviolet absorption is important, titanium oxide (TiO2), etc. are used; and when infrared radiation is important, iron sand, etc. are used.

[0032] The base material is formed into granules, similar to the additives. The thermal spray material is a mixed powder in which the base material and additives are mixed in predetermined proportions. The base material can be made of synthetic resins or ceramics, etc., with the aim of preventing oxidation and deterioration of the additives.

[0033] In addition, the electromagnetic shielding function of the thermal spray coating may be enhanced by including a metal material in the base material, or the dielectric absorption loss of the thermal spray coating may be enhanced by including a resin material or ceramic material in the base material.

[0034] In this example, plasma spraying is used as the thermal spraying method, but it is not limited to this method; high-speed gas flame spraying, gas flame spraying, arc spraying, etc., can also be used.

[0035] Figure 1 is a side view illustrating the configuration of a plasma spraying apparatus for spraying thermal spray material onto a substrate. The plasma spraying apparatus includes a spray gun (plasma spray torch) 51 whose axis is directed toward the substrate W that is to be sprayed. The spray gun 51 has a cathode 52, a positive electrode 53, a supply port (supply unit) 54 that supplies granular thermal spray material along with a carrier gas to the generated plasma jet PJ, and a supply port (supply unit) 56 that supplies working gas (plasma gas) to the two electrodes 52 and 53.

[0036] The cathode 52 is a linear terminal located on the axis S, with its tip facing the substrate 1. The anode 53 is located closer to the substrate W than the cathode 52 and is formed into a cylindrical shape with the same axis as the cathode 52, and at least a part of it constitutes a nozzle for ejecting the plasma jet PJ.

[0037] The supply port 54 is positioned on the tip side of the nozzle 53 (in the illustrated example, closer to the substrate W than the nozzle 53) so as to intersect (perpendicular to) the axis O of the nozzle 53, and its tip-side supply port 54a is close to the open end of the anode 53 that is farther from the cathode 52. The supply port 56 is positioned on the cathode 52 side so as to intersect (perpendicular to) the axis O of the cathode 52, and its tip-side supply port 56a is directed toward the cathode 52.

[0038] A thermal spraying method using this plasma spraying apparatus will now be described. First, a DC voltage is applied to two electrodes 52 and 53 using a power supply (not shown) to generate an arc, and working gas is supplied to the arc from the supply port 56a of the supply port 56, generating a plasma jet PJ that is ejected from the nozzle 54 along its axis O onto the substrate W.

[0039] In this state, when granular thermal spray material is supplied to the plasma jet PJ along with the carrier gas from the supply port 54, the thermal spray material is melted and accelerated as it collides with the surface of the substrate W, forming a thermal spray coating on the surface, thereby completing the manufacture of the protective member (member body).

[0040] This thermal spray coating 2 makes it possible to impart the various functions described above to the protective member, allowing it to be used in a variety of applications.

[0041] Examples of devices to which protective materials can be applied include PC casings, electronic control units (PCU, ECU), information and communication terminals such as smartphones and portable tablets, batteries, inverters, converters, motors, wireless power supply systems, electromechanical systems, cameras, GPS sensors or millimeter-wave radar, and other collision avoidance sensors installed in automobiles.

[0042] In addition, X-ray imaging equipment, ultrasound diagnostic equipment, wireless portable DR, radiograph equipment, This protective component can also be applied to health, medical, and nursing care-related equipment such as mammography systems, AEDs, hyperthermia devices, microwave therapy devices, catheterization lab equipment, automated laboratory chemical analyzers, ICU data management systems, medical telemetry systems, electrocardiogram monitors, nursing care robots, rehabilitation and functional training equipment, or automated excretion processing devices.

[0043] Furthermore, this protective material can also be applied to aerospace-related equipment such as aircraft and ship beacons, air traffic control tower radio equipment, stealth and radar wave countermeasures equipment, satellite cameras, weather radar, or the interior walls of space stations.

[0044] Furthermore, this protective component can also be applied to control panel cabinets, various sensors and laser measuring instruments, earthquake sensors (seismometers), seismic sensors (earthquake detectors), and outdoor equipment such as surveillance cameras.

[0045] Figure 2 is a cross-sectional view of a case applied to the present invention. The case, which seals and covers the entire target space S in which the object O is placed, is composed of a case body (member body) 1 formed in the shape of a rectangular parallelepiped. Incidentally, the case body 1 has, as described above, a peripheral wall portion that surrounds the periphery of the target space S, a bottom portion that covers the side directly below the target space S, and a ceiling portion that covers the side directly above the target space S.

[0046] A portion or all (in the illustrated example) of the surface layer of the case body 1, including its outer or inner surface (outer surface in the illustrated example), is covered by a thermal spray coating 2. In other words, a thermal spray coating 2 is formed on the inner or outer surface of the case body 1.

[0047] The case body 1 is composed of multiple segmented pieces 3, 3. The segmented pieces 3, 3 are joined together by welding the joints 4, 4 of adjacent segmented pieces 3, 3 to each other, or by fixing them with fasteners or the like, thereby forming at least a part (all in the illustrated example) of the case.

[0048] The divided pieces 3,3 in this example are a pair of upper and lower halves that constitute a rectangular parallelepiped case. That is, each halved piece 3 is molded in a concave shape with one side open (specifically, a rectangular parallelepiped shape with one side open). The open side of the halved piece 3 constitutes a joint 4 that connects to the other halved piece 3.

[0049] The pair of halves 3,3 are positioned with their inner surfaces facing each other so that the rectangular annular joints 4,4 face each other, and the joints 4,4 are fixed together by welding or the like.

[0050] Specifically, the opposing end faces 4a, 4a of the upper and lower joints 4, 4 become the joining surfaces that are joined in a surface-to-surface contact state. This joining surface 4a is a flat surface formed in a rectangular annular shape along the outer circumferential surface of the case when viewed from the bottom or in a plan view. The thermal spray coating 2 is formed over the entire or substantially entire area including one or both (one in the illustrated example) of this pair of joining surfaces 4a, 4a.

[0051] Furthermore, objects O such as motors and electronic circuits that generate electromagnetic waves, or electronic components that may malfunction due to electromagnetic interference, are placed in the target space S formed inside the base material 1.

[0052] In a case configured as described above, even if a resin material with a low specific gravity is selected as the base material 1 to reduce the overall weight, sufficient electromagnetic shielding functionality can be provided to the case by selecting an appropriate material as the thermal spray material.

[0053] Furthermore, it is possible to appropriately select materials from the above-mentioned options to ensure the various functions described above as thermal spray materials, thereby providing the necessary functions.

[0054] As shown in Figure 3, the thermal spray coating 2 may be given multiple functions. In the example shown in the figure, an electrical circuit or electronic device containing an IC chip that generates electromagnetic noise is placed in the target space S as the object O. The main material (substrate) of the case body 1 is made of synthetic resin. The thermal spray coating 2 has a two-layer structure and is formed on the inner or outer side (in the illustrated example) of the case body 1.

[0055] The inner layer 2a, located inside the thermal spray coating 2, enhances its ability to absorb electromagnetic noise from the object O. Specifically, the inner layer 2a is an electromagnetic wave absorbing coating. On the other hand, the outer layer 2b, located outside the thermal spray coating 2, enhances its ability to reflect or absorb external electromagnetic waves. Specifically, the outer layer 2b uses a conductive metal coating to increase reflection loss.

[0056] This configuration prevents electromagnetic waves from leaking out of the case from the object O, and also effectively prevents malfunctions of the object O due to electromagnetic noise. In other words, it is possible to achieve both the function of preventing electromagnetic interference (EMI) and the function of preventing electromagnetic interference (EMS).

[0057] Incidentally, when using a metal case to shield external electromagnetic waves from the object O, while the reflection of external electromagnetic waves can prevent their transmission, electromagnetic waves generated by the object O itself are reflected from the inner surface of the case and irradiate the object O, causing malfunctions. However, with a structure like the one shown in Figure 3, electromagnetic waves from the object O can be absorbed by the inner layer 2a, thus improving this drawback.

[0058] Furthermore, if a case made of synthetic resin is used, shielding electromagnetic waves from the object O becomes inherently difficult. Moreover, in such cases, if a sheet material with electromagnetic shielding properties is attached to the inner surface, it is necessary to lay the sheet material without any gaps across the entire inner surface, which is time-consuming, and depending on the shape of the case, it may be impossible to do so at all. In contrast, the structure shown in Figure 3 does not have these problems.

[0059] Furthermore, if the case body 1 is constructed by forming a thermal spray coating 2 having electromagnetic wave absorbing properties on the outer surface or on the outer side of a base material formed in the shape of a conductive metal case, the same functionality as shown in Figure 3 can be provided. However, in this case, since conductive metal material is used as the main material, the case itself becomes heavy. In contrast, the configuration shown in Figure 3 makes it easy to reduce weight.

[0060] Furthermore, it is not necessary to form the thermal spray coating 2 in multiple layers; it is also possible to provide multiple functions with a single layer.

[0061] Furthermore, the case does not necessarily need to seal the target space S; as shown in Figure 4, it may have an opening 1a that leaves part or most of the space open. Also, although Figure 2 illustrates an example in which one member body 1 is composed of multiple molded pieces, the member body 1 may be composed of a single molded member, as shown in Figure 4.

[0062] Furthermore, the number of segmented pieces 3 constituting the main body 1 is not limited to two; there can be three, four, or any other number. In addition, in the figure, a thermal spray coating 2 is formed on the inner surface of the main body 1.

[0063] Furthermore, the formation of the thermal spray coating 2 on the joint surfaces 4a, 4a is not mandatory and may be omitted. In this case, if the thermal spray coating 2 is formed on the outer or inner surface after joining the multiple divided pieces 3, 3 at the joint surfaces 4a, 4a, the boundary between the outer surfaces or the boundary between the inner surfaces of the divided pieces 3, 3 will be covered by the thermal spray coating 2, resulting in a flush surface and preventing electromagnetic waves from entering through the gap formed between the joint surfaces 4a, 4a.

[0064] Next, other embodiments of the present invention will be described based on Figures 5 and 6, with respect to aspects that differ from the embodiments described above.

[0065] Figure 5 is a cross-sectional view of a case according to another embodiment of the present invention, and Figure 6 is an enlarged view of the joint portion of the case in Figure 5. The member body 1 is composed of a pair of upper and lower divided pieces 3, 3. However, unlike the above-described embodiment, the pair of divided pieces 3, 3 are not molded to be vertically symmetrical with respect to each other. Instead, the two are joined by fitting and inserting the outer circumferential surface of the joint portion 7, which is the open side portion of the other divided piece 3, into the inner circumferential surface of the joint portion 6, which is the open side portion of one divided piece 3.

[0066] In other words, a joint surface 6a is formed over the entire circumference of the inner circumferential surface of the joint 6 located at the lower part of one divided piece 3 (specifically the upper divided piece 3), and a joint surface 7a is formed over the entire circumference of the inner circumferential surface of the joint 7 located at the upper part of the other divided piece 3 (specifically the lower divided piece 3).

[0067] In this example, since the peripheral walls of each segmented piece 3,3 are formed in a rectangular annular shape in a plan view, the joint surfaces 6a,7a can be brought into surface contact with each other by a combination of flat surfaces. However, if a part of the peripheral wall of case 1 is curved in an arc shape in a plan view, the joint surfaces 6a,7a are also formed in a corresponding arc shape or the like. Then, a thermal spray coating 2 is formed over the entire joint surfaces 6a,7a of the member body 1.

[0068] Furthermore, the joints 6 and 7, which are the parts where the upper and lower divided pieces 3, 3 overlap and are joined together, are each provided with through holes 6b and 7b, through which the fastening bolts 8 are inserted together. The through holes 6b and 7b are formed in the area from the inner surface to the outer surface of each divided piece 3 (base material 1).

[0069] A thermal spray coating 2 is formed on the entire inner surface of the insertion holes 6b and 7b. The joints 6 and 7 are fastened and fixed together by bolts 8, which are inserted into the insertion holes 6b and 7b and whose tips protrude from the joints 6 and 7, and nuts 9 that are screw-engaged to the tips of bolts 8, thereby joining and fixing the divided pieces 3 and 3 together.

[0070] Next, other embodiments of the present invention will be described with reference to Figures 7 and 8, showing how they differ from the embodiments described above.

[0071] Figure 7 is a cross-sectional view of a case according to another embodiment of the present invention, and Figure 8 is an enlarged view of the joint portion of the case in Figure 7. The base material 1 is composed of a pair of upper and lower divided pieces 3, 3. The pair of divided pieces 3, 3 are molded to be symmetrical in shape. An annular flange-shaped joint portion 11 is formed at the open end of each divided piece 3, extending integrally outward around its entire circumference.

[0072] The joining surfaces 11a, 11a of the upper and lower joints 11, 11 are formed horizontally and flat. A thermal spray coating 2 is formed over the entire area of ​​one or both (both in the illustrated example) of the pair of joining surfaces 11a.

[0073] The upper and lower divided pieces 3,3 are fastened and secured together by bolts 12, with their joint surfaces 11a,11a in close contact. The bolts 12 are inserted together into the through holes 11b,11b drilled in the pair of joints 11,11, with their ends protruding from either the upper or lower joint. Nuts 13 are screw-engaged onto these ends, and by tightening the bolts 12 in this state, the joints 11,11 are fastened and secured together, and the divided pieces 3,3 are joined by their joint surfaces 11a,11a.

[0074] Incidentally, since this joint 11 is located in a part that is not on either the inner or outer surface of the member body 1, there is little need to form a thermal spray coating 2 on the inner circumferential surface of the through hole 11b drilled in the joint. However, this is not prohibited.

[0075] Also, the figure 7 As shown by the dashed line, the thermal spray coating 2 may be formed continuously from the outer surface to the inner surface or from the inner surface to the outer surface of the member body 1. In this case, the heat generated on the object O side can be released to the outside of the case through the thermal spray coating 2, improving the heat dissipation function.

[0076] Furthermore, Figure 7 A heat sink or other heat dissipation body 14, shown by dashed lines, may be provided on the outer surface of the case in contact with the thermal spray coating 2 to further efficiently cool the target space S. Incidentally, if the target object O is a heat-generating circuit or electronic component, it is desirable to provide this object in contact with the thermal spray coating 2 as well. [Explanation of Symbols]

[0077] 1. Main component 2. Thermal spray coating 3 pieces 4 Joint 4a Joint surface (end surface) 6 Joint 6a Joint surface 6b Through hole 7 Joint 7a Joint surface 7b Through hole 11 Joint 11a Joint surface S Target space

Claims

1. A protective member that protects the target space, Equipped with a main component, The member body is constructed by forming a thermal spray coating by thermal spraying on at least one of the inner surface of the wall portion that faces the target space or the outer surface that is opposite to the inner surface of the wall portion, which is a base material molded into the shape of a housing, case, pipe, or cover, and which includes a wall portion that covers at least a part of the target space. The aforementioned thermal spray coating contains a metal material, The thermal spray coating is formed continuously over the range from the inner surface to the outer surface of the member body, thereby configuring it to release heat from the target space to the outside. The member body has a plurality of divided pieces, By joining adjacent divided pieces together, at least a portion of the base material is formed. Each of the connecting segments is provided with a through-hole through which a bolt is inserted to fasten and secure the two together. The thermal spray coating is formed on the inner circumferential surface of each insertion hole. The thermal spray coatings formed on the inner circumferential surfaces of two through-holes through which the same bolt is inserted are connected and continuous, and one of the thermal spray coatings is formed to the extent that it reaches the outer surface, while the other thermal spray coating is formed to the extent that it reaches the inner surface. A protective member characterized by the following features.

2. At least a portion of the joint portion of the divided piece that is joined to another divided piece has a thermal spray coating that is continuous with the thermal spray coating on the inner surface and extends to the outer surface, or a thermal spray coating that is continuous with the thermal spray coating on the outer surface and extends to the inner surface. The protective member according to claim 1.

3. Each of the two joining parts that connects them has a joining surface formed on it that makes surface contact with the other. The thermal spray coating is formed on at least one of the two joining surfaces to be joined. The protective member according to claim 2.

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