JP6233099B2 - Damping member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a damping member for damping sound and vibration and a method for manufacturing the same.

  In transportation equipment such as automobiles, railway vehicles, ships, and airplanes, sound and vibration are generated due to various factors.

  For example, an engine or motor that is a power source of an automobile generates sound and vibration when driven. Further, when the vehicle is running, sound and vibration are generated in the vehicle body due to road surface unevenness and the like. If such sound and vibration are transmitted as they are to the interior of the vehicle (cabin), the passengers in the vehicle are uncomfortable.

  Therefore, techniques for suppressing the sound and vibration as described above have been developed. For example, Patent Document 1 describes an asphalt sheet. The asphalt sheet of Patent Document 1 is used by being affixed to a vehicle floor panel as a countermeasure against vehicle vibration and noise.

  For example, Patent Document 2 discloses a sound attenuation patch. The sound attenuating patch of Patent Document 2 is bonded to the main panel via an adhesive layer, and attenuates noise and vibration.

Japanese Patent Laid-Open No. 10-324186 Special table 2013-535030 gazette

  When an asphalt sheet as described in Patent Document 1 is used, an effect of suppressing sound and vibration is recognized. However, the thickness of the asphalt sheet itself is as thick as 3 to 6 mm. For this reason, for example, when an asphalt sheet is affixed to a dash panel and a floor panel of an automobile, the interior space becomes narrow.

  Further, in Patent Document 2, a plate-like member made of metal is used as a sound attenuation patch. However, as a result of intensive studies by the present inventors, a plate-like member may be simply pasted on a dash panel of an automobile or the like. It was found that sound and vibration could not be sufficiently suppressed. Specifically, for example, simply attaching a plate-like member to the dash panel cannot sufficiently improve the rigidity of the dash panel. For this reason, it has been found that the vibration characteristics of the dash panel in the low frequency range cannot be improved, and the sound and vibration may not be sufficiently suppressed in the dash panel.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a damping member having a small thickness that can sufficiently suppress transmission of sound and vibration, and a method for manufacturing the same.

  The present invention provides a damping member comprising a metal main body, an adhesive layer applied to the main body, and a metal patch member attached to the main body via the adhesive layer. In order to improve the vibration characteristics of the damping member while preventing an increase in thickness of the damping member, intensive studies were conducted.

  As a result, in order to improve the vibration characteristics of the damping member while preventing an increase in the thickness of the damping member, a plurality of convex surfaces and a plurality of concave surfaces are formed on the surface of the patch member opposite to the main body. It has been found that it is important that the main body portion and the patch member have an uneven cross-sectional shape (embossed shape). More specifically, when the main body portion and the patch member have a concavo-convex shape, the rigidity of the attenuation member is improved. Therefore, even if the thickness of the main body portion and the patch member is reduced, the rigidity of the attenuation member is sufficiently increased. Can be secured. As a result, the rigidity of the damping member can be sufficiently improved while preventing an increase in the thickness of the damping member, so that the vibration characteristics (particularly, the vibration characteristics in the low frequency range) of the damping member can be sufficiently improved.

  As a result of the study by the present inventors, it is found that the patch member preferably has a 30 mm square region in which the area ratio of the concave surface is 30% or more and 70% or less in order to obtain the above effect. It was.

  The present invention has been completed on the basis of the above findings, and the gist of the present invention is the following damping member and manufacturing method thereof.

(1) A metal and plate-like main body, an adhesive layer applied to the main body, and a metal and plate-like patch member attached to the main body via the adhesive layer. Prepared,
The main body portion and the patch member have a concavo-convex shape so that a plurality of convex surfaces and a plurality of concave surfaces are formed on the surface of the patch member opposite to the main body portion,
The damping member, wherein the surface of the patch member has a 30 mm square region in which the area ratio of the concave surface is 30% to 70%.

  (2) The attenuation member according to (1), wherein the height of the convex surface is 0.5 to 8.0 mm with reference to the concave surface.

  (3) The attenuation member according to (1) or (2), wherein the patch member has a thickness of 0.3 to 2.0 mm.

  (4) The attenuation member according to any one of (1) to (3), wherein at least a part of a portion of the main body portion to which the patch member is not attached has an uneven cross-sectional shape.

(5) A method of manufacturing a damping member including a main body and a patch member,
Applying an adhesive to a predetermined region of the first metal plate serving as the main body;
Attaching the second metal plate to be the patch member to the predetermined region of the first metal plate;
An unevenness is formed in the first metal plate and the second metal plate by sandwiching the first metal plate and the second metal plate by an upper punch having an uneven shape on the lower surface and a lower punch having an uneven shape on the upper surface. While cutting the first metal plate into a predetermined shape by the upper punch and the lower punch, to obtain the main body and the patch member,
In the step of obtaining the main body portion and the patch member, a plurality of convex surfaces and a plurality of concave surfaces are formed on the surface of the patch member opposite to the main body portion, and the area ratio of the concave surface to the surface is 30. A method for manufacturing an attenuation member, wherein irregularities are formed on the main body portion and the patch member so as to have a 30 mm square region that is not less than 70% and not more than 70%.

  According to the present invention, it is possible to obtain a damping member having a small thickness that can sufficiently suppress transmission of sound and vibration.

1 is an external perspective view of a damping member according to an embodiment of the present invention. Sectional drawing of the attenuation member which concerns on one Embodiment of this invention Top view of patch member The figure for demonstrating an example of the manufacturing method of a damping member The figure for demonstrating an example of the manufacturing method of a damping member External perspective view of a damping member according to another embodiment of the present invention External perspective view of shock absorber tower Cross section of trunk floor panel External perspective view of floor tunnel Sectional drawing which shows the other example of a patch member The top view which shows the damping member of this invention example and the comparative example 1 The figure which shows the bending rigidity of the damping member of this invention example and Comparative Examples 1 and 2.

  Hereinafter, the damping member of the present invention will be described in detail. FIG. 1 is an external perspective view of an attenuation member 10 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the attenuation member 10. FIG. 3 is a plan view of the patch member 16 described later. The damping member 10 is used as, for example, a dash panel of an automobile.

  As shown in FIGS. 1 and 2, the damping member 10 includes a plate-like main body 12, an adhesive layer 14 (see FIG. 2) applied to the main body 12, and the main body through the adhesive layer 14. 12 and a plate-like patch member 16 bonded to 12. In the present embodiment, the patch member 16 is smaller than the main body 12 in plan view. The main body 12 and the patch member 16 are joined at a plurality of spot welds SW. Thus, in this embodiment, the main-body part 12 and the patch member 16 are being mutually fixed by the adhesive agent and spot welding.

  As shown in FIG. 1, when the damping member 10 is used as a dash panel of an automobile, a cross member 19 is provided on the front surface of the damping member 10 (the front surface in the front-rear direction of the automobile). In the present embodiment, the patch member 16 is provided at a position facing the cross member 19 with the main body 12 interposed therebetween.

  The main body 12 and the patch member 16 are made of a metal material. More specifically, the main body 12 is made of, for example, a steel plate (thin steel plate), and the patch member 16 is made of, for example, a metal plate such as a steel plate (thin steel plate), a stainless steel plate, or an aluminum plate. The tensile strength of the patch member 16 is, for example, 270 to 1180 MPa. As an adhesive agent used as the adhesive bond layer 14, an acrylic resin can be used, for example.

  As shown in FIG. 2, the patch member 16 has an uneven cross-sectional shape (embossed shape). As shown in FIGS. 2 and 3, the patch member 16 has a plurality of convex surfaces 16 a, a plurality of concave surfaces 16 b, and a plurality of inclined surfaces 16 c on the surface 17 a opposite to the main body portion 12. The convex surface 16a is a surface protruding to the opposite side of the main body 12 with respect to the concave surface 16b. The inclined surface 16c is a surface that connects the convex surface 16a and the concave surface 16b and is inclined with respect to the convex surface 16a and the concave surface 16b. Each of the convex surface 16a and the concave surface 16b has a quadrangular shape in plan view or a combination of a plurality of quadrangles. In the present embodiment, a plurality of convex surfaces 16a, a plurality of concave surfaces 16b, and a plurality of inclined surfaces 16c are formed on the entire patch member 16. In FIG. 3, the concave surface 16b is hatched so that the convex surface 16a and the concave surface 16b can be clearly recognized.

  Although detailed description is omitted, as shown in FIG. 2, the surface 17b of the patch member 16 on the main body 12 side is parallel to the plurality of convex surfaces 16a, the plurality of concave surfaces 16b, and the plurality of inclined surfaces 16c, respectively. A plurality of surfaces are formed. That is, in the present embodiment, the surfaces 17a and 17b of the patch member 16 are configured to be parallel (or substantially parallel) to each other. In the present embodiment, the portion of the main body 12 that faces the patch member 16 has a cross-sectional uneven shape similar to that of the patch member 16.

  The thickness t1 of the main body 12 is, for example, 0.5 to 3.2 mm, and more preferably 0.7 to 2.3 mm. The thickness t2 of the patch member 16 is, for example, 0.3 to 2.0 mm, and more preferably 0.4 to 1.0 mm. The height h1 of the convex surface 16a with respect to the concave surface 16b is, for example, 0.5 to 8.0 mm, and more preferably 1.0 to 5.0 mm.

  Referring to FIG. 3, the patch member 16 is configured such that the area ratio (area ratio in plan view) of the concave surface 16 b is 30% or more and 70% or less in an arbitrary 30 mm square region 18. In other words, the surface 17a of the patch member 16 has a 30 mm square region 18 in which the area ratio of the concave surface 16b is 30% to 70%.

  4 and 5 are diagrams for explaining an example of a manufacturing method of the damping member 10. In FIG. 5, illustration of the adhesive layer 14 is omitted.

  As shown in FIG. 4A, for example, first, a first metal plate 20 (hereinafter abbreviated as metal plate 20) and a second metal plate 22 (hereinafter abbreviated as metal plate 22) are prepared. Then, an adhesive is applied to the predetermined region 24 of the metal plate 20. Next, as shown in FIG. 4B, a metal plate 22 is attached to the region 24 where the adhesive is applied. Then, as shown in FIG.4 (c), the main-body part 12 and the patch member 16 are joined by spot welding. FIG. 4C shows a plurality of spot welds SW formed by spot welding.

  After the metal plate 22 is attached to the metal plate 20, as shown in FIG. 5, irregularities are formed on the metal plate 20 and the metal plate 22 using, for example, a press machine 30. The press machine 30 includes, for example, a hollow upper die 32a, a hollow lower die 32b, a columnar upper punch 34a, and a columnar lower punch 34b. The upper punch 34a and the lower punch 34b are provided in the hollow portions of the upper die 32a and the lower die 32b so as to be vertically movable. A plurality of irregularities are formed on the lower surface of the upper punch 34a and the upper surface of the lower punch 34b, respectively.

  Hereinafter, a method for forming irregularities on the metal plates 20 and 22 will be specifically described. As shown in FIG. 5A, for example, first, the metal plates 20 and 22 are supported by the upper die 32a and the lower die 32b. Next, as shown in FIG. 5B, the metal plates 20 and 22 supported by the upper die 32a and the lower die 32b are clamped (pressed) by the upper punch 34a and the lower punch 34b. Thereby, irregularities are formed on the metal plates 20 and 22.

  Thereafter, as shown in FIG. 5C, the upper punch 34a and the lower punch 34b are moved downward with respect to the upper die 32a and the lower die 32b in a state where the metal plates 20 and 22 are sandwiched between the upper punch 34a and the lower punch 34b. (Or upward). Thereby, as shown to FIG.5 (c) and (d), the predetermined area | region of the metal plate 20 is cut | disconnected, and the attenuation member 10 is completed. Thus, in this embodiment, the attenuation member 10 can be produced in a short time by cutting the metal plate 20 into a predetermined shape while forming irregularities on the metal plates 20 and 22.

  In the damping member 10 according to the present invention, as described above, the main body portion 12 and the patch member 16 have a concavo-convex shape. Therefore, even if the thickness of the main body portion 12 and the patch member 16 is reduced, the rigidity of the damping member 10 is increased. It can be improved sufficiently. Thereby, the rigidity of the attenuation member 10 can be sufficiently improved while suppressing an increase in the thickness of the attenuation member 10. That is, the vibration characteristic in the low frequency region of the damping member 10 can be improved while suppressing an increase in the thickness of the damping member 10. Therefore, for example, by using the damping member 10 as a dash panel of an automobile, it is possible to sufficiently suppress the transmission of sound and vibration into the vehicle while preventing the interior space of the automobile from becoming narrow.

  In this embodiment, after the patch member 16 is attached to the main body 12, the main body 12 and the patch member 16 are simultaneously formed with unevenness. In this case, since the adhesive layer 14 having a uniform thickness can be formed in the entire area between the main body 12 and the patch member 16, the vibration characteristics of the damping member 10 can be reliably improved.

  In this embodiment, when the main body 12 having a predetermined shape is cut out from the metal plate 20, the metal plates 20 and 22 are formed with irregularities. That is, in one process, the main body portion 12 can be cut out and the unevenness can be formed. Thereby, the increase in a processing process can be suppressed and processing cost can be reduced.

  In the present embodiment, the patch member 16 is provided at a position facing the cross member 19. Here, the present inventors have studied in detail the transmission path of sound and vibration from the drive source of the automobile to the interior (cabin). As a result, it was found that the main transmission path of sound and vibration from the drive source to the vehicle includes the joint between the main body 12 and the cross member 19. Therefore, in the present embodiment, the patch member 16 is provided at a position facing the cross member 19. As a result, transmission of sound and vibration into the vehicle can be more reliably suppressed.

  In the above-described embodiment, the case where the whole patch member 16 has a cross-sectional uneven shape has been described, but only a part of the patch member 16 may have a cross-sectional uneven shape. In other words, a part of the patch member 16 may be a simple plate shape having no unevenness.

  In the above-described embodiment, the case where the portion of the main body portion 12 where the patch member 16 is affixed has a concavo-convex shape, but the portion of the main body portion 12 where the patch member 16 is not attached is described. At least a portion may have a concavo-convex shape. In this case, since the rigidity of the portion of the main body 12 where the patch member 16 is not attached can be improved, the rigidity of the attenuation member 10 can be further improved while suppressing an increase in the thickness of the attenuation member 10. Thereby, the vibration characteristic in the low frequency region of the damping member 10 can be further improved. In the case where a part of the main body portion 12 has a concavo-convex shape, for example, a plurality of convex surfaces are formed on the surface of the main body portion 12 such that a region similar to the region 18 of the patch member 16 is formed in the main body portion 12. And forming a plurality of concave surfaces.

  In the above-described embodiment, the damping member 10 having the single patch member 16 has been described. For example, as shown in FIG. 6, the damping member 10a may include a plurality of patch members 40a and 40b. In this case, for example, since the patch members 40a and 40b can be attached only to the portions where the vibration characteristics are particularly desired to be improved, the patch members 40a and 40b can be made small. Thereby, the attenuation member 10a can be reduced in weight.

  In the above-described embodiment, the case where each of the convex surface 16a and the concave surface 16b has a square shape in plan view or a combination of a plurality of quadrangles has been described, but the shape of the convex surface and the concave surface is not limited to the above-described example. For example, each of the convex surface and / or the concave surface may have a polygonal shape other than a quadrangle or a combination of a plurality of polygons other than a quadrangle. For example, the convex surface and / or the concave surface may each have a circular shape or an elliptical shape. Further, each of the convex surface and / or the concave surface may have an outer edge that is regularly or irregularly curved. The shape of the inclined surface may be appropriately changed according to the shape of the convex surface and the concave surface. Further, instead of the inclined surface, a surface perpendicular to the convex surface and the concave surface may be provided.

  In the above-described embodiment, the case where the damping member of the present invention is used as a dash panel has been described. However, the damping member of the present invention may be used as a member other than the dash panel.

  For example, as shown in FIG. 7, the damping member of the present invention may be used as the shock absorber tower 42. The shock absorber tower 42 includes a main body portion 44 that houses a shock absorber (not shown), and a hollow disk-shaped patch member 46 that is attached to the main body portion 44 via an adhesive layer (not shown). The patch member 46 is affixed to the top 44a of the main body 44 (a portion that supports a shock absorber (not shown)). The main body 44 and the patch member 46 are made of the same material as the main body 12 and the patch member 16 described above, and have the same uneven shape as the main body 12 and the patch member 16. Moreover, the main-body part 44 and the patch member 46 are joined by spot welding.

  Here, the present inventors have studied in detail the transmission path of sound and vibration from the drive source of the automobile to the interior of the vehicle. As a result, it was found that the shock absorber tower is included in the main transmission path of sound and vibration from the drive source to the vehicle interior. Furthermore, as a result of the study by the present inventors, it has been found that the vibration becomes large at the top of the shock absorber tower. Therefore, the present inventors have arranged the patch member 46 on the top 44a of the shock absorber tower 42. As a result, the rigidity of the top 44a of the shock absorber tower 42 can be improved, and sound and vibration can be efficiently suppressed in the shock absorber tower 42.

  For example, the damping member of the present invention may be used as the trunk floor panel 48 as shown in FIG. The trunk floor panel 48 includes a main body 50 that forms the bottom of the trunk, and a patch member 52 that is attached to the main body 50 via an adhesive layer (not shown). The main body 50 has a housing portion 50 a that houses the spare tire 54. The patch member 52 has a disk shape and is attached to the bottom surface of the accommodating portion 50a. The main body 50 and the patch member 52 are made of the same material as the main body 12 and the patch member 16 described above, and have the same uneven shape as the main body 12 and the patch member 16. Moreover, the main-body part 50 and the patch member 52 are joined by spot welding.

  By providing the patch member 52 as described above, the rigidity of the bottom surface of the housing portion 50a can be improved. Thereby, even when the spare tire 54 sways in the housing portion 50a while the vehicle is running, the vibration of the housing portion 50a can be suppressed. As a result, transmission of sound and vibration from the trunk floor panel 48 into the vehicle can be suppressed.

  For example, as shown in FIG. 9, the damping member of the present invention may be used as a floor tunnel portion 56 (a member constituting a car floor). The floor tunnel portion 56 includes a main body portion 58 bent so as to protrude upward, and a patch member 60 attached to the main body portion 58 via an adhesive layer (not shown). The patch member 60 is attached so as to cover at least a part of the main body 58 from above. The main body 58 and the patch member 60 are made of the same material as the main body 12 and the patch member 16 described above, and have the same uneven shape as the main body 12 and the patch member 16. Moreover, the main-body part 58 and the patch member 60 are joined by spot welding.

  By providing the patch member 60 as described above, the rigidity of the floor tunnel portion 56 can be improved, and the vibration characteristics of the floor tunnel portion 56 can be improved. Thereby, it can suppress that the vibration and sound which generate | occur | produced with the drive source are transmitted in the vehicle via the floor tunnel part 56. FIG.

  Although the detailed description with reference to the drawings is omitted, the damping member of the present invention may be used as another automobile part such as a floor panel or a wheel house inner.

  In the above-described embodiment, the patch member 16 has been described in which the plurality of convex surfaces 16a have the same height and the plurality of concave surfaces 16b have the same height. The heights of the surfaces 62a, 62b, 62c, 62d, 62e, 62f, and 62g may be different. For example, when the plurality of surfaces 62a to 62g shown in FIG. 10 exist in the region 18 (see FIG. 3), the height H1 of the highest surface 62e and the lowest surface 62b. The surface 62b, 62d, 62f at a position lower than the height H3 is defined as a concave surface, and the surfaces 62a, 62c, 62e, 62g at a position higher than the concave surface are defined with respect to a height H3 intermediate to the height H2. Convex surface. Further, although detailed description is omitted, in the damping member provided with the patch member 62, the portion of the main body portion that faces the patch member 62 has a cross-sectional uneven shape similar to that of the patch member 62.

  Hereinafter, the effects of the present invention will be described more specifically by way of examples. However, the present invention is not limited to the following examples.

  In order to verify the effect of the present invention, the present inventors produced the damping member of the present invention and the damping members of Comparative Examples 1 and 2. As shown in Table 1 below, the damping members of the present invention example and comparative example 1 were constituted by a main body portion and a patch member. On the other hand, the damping member of Comparative Example 2 was composed of only the main body, that is, a single plate.

  As shown in Table 1 and FIG. 11, in the damping members of the present invention example and the comparative example 1, a 440 MPa class steel plate having a thickness of 1.0 mm, a length of 500 mm, and a width of 600 mm was used as the main body. As the patch member, a mild steel plate having a thickness of 0.4 mm, a length of 400 mm, and a width of 500 mm was used. The patch member was affixed to the center of the main body using acrylic resin. After affixing the patch member to the main body, the outer periphery of the patch member was joined to the main body by spot welding. Spot welding was performed at a pitch of 50 mm. In the damping member of Comparative Example 2, a 440 MPa class steel plate having a thickness of 1.4 mm, a length of 500 mm, and a width of 600 mm was used as the main body.

  In the present invention example, the patch member and the main body portion (specifically, the portion of the main body portion facing the patch member so that the height of the convex surface of the patch member (corresponding to the height h1 in FIG. 2) is 3 mm. ) Was embossed. On the other hand, the damping members of Comparative Examples 1 and 2 are not embossed.

  The first-order mode frequencies of the present invention and the damping members of Comparative Examples 1 and 2 having the above-described configurations were measured by experiments. The measurement results are shown in Table 2 below. In Table 2, the frequencies of the damping members of the present invention and Comparative Examples 1 and 2 are shown in a dimensionless manner with the frequency of the damping member of Comparative Example 2 as a reference.

  Comparing the inventive example and the comparative example, the frequency of the primary mode of the inventive example is about 1.5 times that of the comparative examples 1 and 2. From this result, it can be seen that according to the present invention, the vibration characteristics of the damping member in the low frequency region can be improved.

  Furthermore, the inventors obtained the bending rigidity of the damping members of the present invention example and the comparative examples 1 and 2 through experiments. In FIG. 12, the bending rigidity of the damping member of the example of this invention and the comparative examples 1 and 2 is shown. In FIG. 12, the bending rigidity of the damping members of the present invention example and Comparative Examples 1 and 2 is shown in a dimensionless manner with reference to the bending rigidity of the damping member of Comparative Example 2.

  As shown in FIG. 12, it can be seen that the bending rigidity of the damping member of Comparative Example 1 in which the patch member is simply bonded to the main body is significantly lower than that of the damping member of Comparative Example 2 made of a single plate. On the other hand, in the damping member of the present invention example in which the main body portion and the patch member were embossed, the bending rigidity was significantly increased as compared with the damping member of Comparative Example 2 made of a single plate. That is, the excellent effect of the present invention was confirmed.

  Since the damping member of the present invention is thin and can sufficiently suppress transmission of sound and vibration, it can be suitably used as a component for transportation equipment. For example, by using the damping member of the present invention as an automobile part, it is possible to sufficiently suppress the transmission of sound and vibration into the vehicle while preventing the vehicle interior space from becoming narrow.

10, 10a Damping member 12, 44, 50, 58 Body 14 Adhesive layer 16, 40a, 40b, 46, 52, 60, 62 Patch member 16a Convex surface 16b Concave surface 18 Region

Claims (5)

A metal and plate-like main body, an adhesive layer applied to the main body, and a metal and plate-like patch member attached to the main body via the adhesive layer;
The main body portion and the patch member have a concavo-convex shape so that a plurality of convex surfaces and a plurality of concave surfaces are formed on the surface of the patch member opposite to the main body portion,
The damping member, wherein the surface of the patch member has a 30 mm square region in which the area ratio of the concave surface is 30% to 70%.   The damping member according to claim 1, wherein the height of the convex surface is 0.5 to 8.0 mm with respect to the concave surface.   The attenuation member according to claim 1 or 2, wherein the patch member has a thickness of 0.3 to 2.0 mm.   The damping member according to any one of claims 1 to 3, wherein at least a part of a portion of the main body portion to which the patch member is not attached has a concavo-convex shape. A method of manufacturing a damping member including a main body and a patch member,
Applying an adhesive to a predetermined region of the first metal plate serving as the main body;
Attaching the second metal plate to be the patch member to the predetermined region of the first metal plate;
An unevenness is formed in the first metal plate and the second metal plate by sandwiching the first metal plate and the second metal plate by an upper punch having an uneven shape on the lower surface and a lower punch having an uneven shape on the upper surface. While cutting the first metal plate into a predetermined shape by the upper punch and the lower punch, to obtain the main body and the patch member,
In the step of obtaining the main body portion and the patch member, a plurality of convex surfaces and a plurality of concave surfaces are formed on the surface of the patch member opposite to the main body portion, and the area ratio of the concave surface to the surface is 30. A method for manufacturing an attenuation member, wherein irregularities are formed on the main body portion and the patch member so as to have a 30 mm square region that is not less than 70% and not more than 70%.

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