Waterproof structure of the housing and manufacturing method of packing

Abstract

To provide a water-proof structure which is desirable for a relatively large housing and can improve the quality and design of a product.SOLUTION: A housing formed by joining a plurality of case bodies together includes: an inner arrangement member attached to the inside of the housing; and a packing formed in a round shape to be arranged along the boundary of joint of the case bodies. The packing is pressed against the case bodies along the joint boundary part by the inner arrangement member.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a waterproof structure for a housing and a method for manufacturing a packing used in the waterproof structure. [Background technology]

[0002] Examples of waterproof structures in the housing of an electronic device, such as a communication device, are shown in Figures 8 and 9. Figure 8 shows a structure in which packing 102 is placed at the joint of an upper case 100 and a lower case 101 joined with screws 103. Figure 9 is a plan view of the housing, showing the state in which upper case 100 and lower case 101 are joined with a large number of screws 103, with annular packing 102 placed inside. As shown in Figs. 8 and 9, a rubber packing 102 is sandwiched in a recess formed by an upper case 100 and a lower case 101, and the packing is screwed in to provide waterproofing.

[0003] Further examples of waterproof structures are shown in Patent Documents 1 and 2 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2011 / 114614 [Patent Document 2] JP 2013-207668 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when using an annular packing as in the waterproof structure shown in FIG. 8 and FIG. 9, the packing becomes larger as the housing becomes larger. When molding packings using a mold, the mold must also become larger in size in proportion to the size of the packing. Also, one mold can only produce one packing at a time. These factors lead to an increase in the unit price of the part and a decrease in manufacturing efficiency.

[0006] Also, to ensure waterproofing and to prevent deformation of the case due to pressure from the packing, it is necessary to keep the spacing of the screws 103 constant, as shown in Fig. 9. If the housing becomes larger, a large number of screws 103 will be required. In particular, for products where design is important, having a large number of exposed screws 103 will detract from the design.

[0007] Therefore, an object of the present invention is to provide a waterproof structure that can be easily adapted to larger housings and a method for manufacturing a packing with high manufacturing efficiency. [Means for solving the problem]

[0008] The waterproof structure of a housing according to the present invention comprises an internal placement member attached to a housing formed by joining a plurality of case bodies, and a ring-shaped gasket that can be positioned along the joint boundary of the plurality of case bodies, and is configured so that the internal placement member presses the gasket against the plurality of case bodies along the joint boundary. For example, in the case of an upper case and a lower case, the packing is pressed along the joint boundary by the internally disposed member.

[0009] The method for manufacturing a gasket according to the present invention includes a step of forming a string-like body by extrusion molding, and a step of generating functional groups that serve as the source of hydrogen bonds on both end surfaces of the string-like body and bonding the two ends together through hydrogen bonds to form a ring. This allows the production of an annular packing without using adhesive. Effect of the Invention

[0010] According to the waterproof structure of the present invention, since the packing is pressed against the case by the internally disposed member, there is no need to deal with the reaction force of the packing in the direction in which multiple cases are joined, and for example, the number of screws can be reduced. This is suitable for the design of even large housings. Furthermore, according to the method for producing a packing of the present invention, it is possible to produce an annular packing with an advantageous cost and improve production efficiency. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an exploded perspective view of a housing according to the embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of a frame according to the embodiment. [Diagram 3] FIG. 2 is an explanatory diagram of a packing according to an embodiment. [Figure 4] FIG. 4 is an explanatory diagram of a flap of the packing according to the embodiment. [Diagram 5] 6A to 6C are explanatory diagrams of deflection of flaps of the packing according to the embodiment. [Figure 6] FIG. 2 is a cross-sectional view of a housing according to an embodiment. [Figure 7] FIG. 4 is an explanatory diagram showing an enlarged view of a portion where a packing is arranged in the embodiment. [Figure 8] FIG. 1 is an explanatory diagram of a conventional waterproof structure. [Figure 9] FIG. 1 is a plan view of a housing having a conventional waterproof structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a waterproof structure and a method for manufacturing a packing according to an embodiment of the present invention will be described with reference to Figs. The exploded perspective view of FIG. 1 shows an upper case 1 and a lower case 2 that constitute a housing 10 of an electronic device according to an embodiment, a frame 3 that is disposed within the housing 10, a packing 4, and screws 5 and 6 for attaching these.

[0013] The housing 10 is an example of a housing for a transmitter for controlling an unmanned flying object or a moving object, such as a drone, a small fixed-wing airplane, a small helicopter, a small car (a so-called radio-controlled car), etc. However, the waterproof structure and the manufacturing method of the packing of the present technology are not limited to these transmitters, and can be applied to the waterproof structure of the housing of various electronic devices and the packing used in the waterproof structure.

[0014] For the sake of explanation, up / down, front / back, left / right will be used in the directions shown in Fig. 1. That is, the direction between the top and bottom surfaces of the housing 10 is the up / down direction, the long direction of the plane of the housing 10 is the left / right direction, and the short direction of the plane of the housing 10 is the front / back direction.

[0015] Housing 10 of the transmitter according to the embodiment is formed by joining upper case 1 and lower case 2 shown in Fig. 1. Upper case 1 and lower case 2 are joined by abutting a lower edge 60a of upper case 1 and an upper edge 60b of lower case 2 against each other, thereby forming an enclosed space inside housing 10. The abutting portion of lower edge 60a and upper edge 60b forms a joining boundary 60 between upper case 1 and lower case 2 (see Fig. 7).

[0016] The joint boundary 60 between the upper case 1 and the lower case 2 is a portion where water may enter the housing 10. Therefore, a waterproof packing 4 and a frame 3 that presses the packing 4 against the housing 10 from the inside are attached to the joint boundary 60.

[0017] The frame 3 is formed of, for example, resin. The frame base 31 constituting the frame 3 has a shape corresponding to the bottom edge 60a of the upper case 1 and the top edge 60b of the lower case 2 (see FIGS. 1 and 2). That is, the frame base 31 has an annular shape and size that is arranged inside the joint boundary 60 and along the joint boundary 60 within the housing 10.

[0018] The frame base 31 has holes in a flange portion integrally formed therewith and screw holes 32, 33 formed as a cylindrical portion. A total of 14 screw holes 33 are provided: four cylindrical portions on the front side, four cylindrical portions on the rear side, three cylindrical portions on the left side, and three cylindrical portions on the right side. The 14 screw holes 33 correspond to 14 screw holes (not shown) provided on the underside of the upper case 1, and are screwed into by the 14 screws 6. In this way, the frame 3 is fixed to the upper case 1.

[0019] Two screw holes 32 are provided in the flanges at the left and right corners on the rear side of the frame base 31, and also in the two cylindrical parts that protrude most toward the center on the left and right front sides. This results in the screw holes 32 being formed at positions that are approximately the four corners. These four screw holes 32 correspond to the four screw holes 21 in the lower case 2 and also correspond to four screw holes (not shown) provided on the underside of the upper case 1, and are screwed together with four screws 5 (only two shown). This fastens the lower case 2, frame 3, and upper case 1 together.

[0020] The packing 4 is made of, for example, silicone rubber and has an annular circumferential length that goes around the inside of the housing 10 along the joint boundary 60 between the upper case 1 and the lower case 2.

[0021] 3 shows a partially cut away state of the annular packing 4. Also, FIG. 4 shows the cross-sectional shape of the packing 4. The cross section of the packing 4 is substantially Σ-shaped as shown in the figure. That is, the packing 4 has a shape in which a pair of flaps 41, 42 protruding from both edges of a base portion 40 are formed. The flap 41 is shaped to protrude from the upper edge 43 of the base 40 in a direction approaching the other flap 42 toward the tip 41a. The flap 42 is shaped to protrude from the lower edge 44 of the base 40 in a direction approaching the other flap 41 toward the tip 42a. Roughly speaking, the flaps 41, 42 protrude in a direction such that the angle θ with respect to the base 40 is an acute angle, as shown in the figure. For the sake of explanation, the space sandwiched between such flaps 41, 42 is referred to as the "flap inner space 50."

[0022] By providing the flaps 41, 42, when the packing 4 abuts against a surface 70 indicated by a dashed line in FIG. 5, the flaps 41, 42 bend in a direction narrowing the space 50 inside the flap as shown in the figure.

[0023] Such a packing 4 is manufactured as follows. (1st step) A string-like body is formed by extrusion molding. In other words, a string-like shape is formed with a cross-sectional shape as shown in Figure 4. The shape of the flaps 41 and 42 is made into a string-like shape by extrusion because it would be difficult to manufacture using a mold that opens up and down due to undercuts. The extruded string-like body is cut to a predetermined length, that is, to a length that wraps around the inside of the housing 10 along the joint boundary 60.

[0024] (2nd process) Functional groups that can form hydrogen bonds are generated on both end faces (cut ends) of a string-like body of a specified length, and the string is bonded together by hydrogen bonds to form a ring.

[0025] The packing 4 is made by gluing both ends of a string-like body together to form a ring, and this joining can be achieved by using an adhesive, or by melting the material with a solvent or heat, and then fusing it. However, these methods inevitably result in damage to the cross-sectional shape due to the adhesive or melted material spilling out. In the vicinity of these spilled areas, there are areas where the adhesion between the packing 4 and the housing 10 becomes discontinuous, which can become a path for water to leak in.

[0026] In addition, the hardness of the adhesive or welding portion is different from that of the base material, and generally becomes harder than the base material in many cases. In this case, the flaps 41 and 42 formed on the packing 4 may not deform as intended, which is also a factor that threatens waterproofing.

[0027] When considering the factors that cause adhesives to adhere to things, it is known that there are three factors: the anchor effect, van der Waals forces, and hydrogen bonds. In particular, it is said that the effect of hydrogen bonds is the greatest. Therefore, it is believed that sufficient adhesive strength can be obtained if functional groups that are the source of hydrogen bonds can be directly added to the surface of the material. Therefore, in this embodiment, the surface of the end face (cut face) of the silicone rubber molded into a string-like body having the cross section shown in Figure 4 is treated to directly generate functional groups, which are then bonded using hydrogen bonds. In this way, problems expected with adhesives, welding, etc. are avoided, and sufficient waterproof performance can be achieved.

[0028] The annular packing 4 manufactured as described above has its base portion 40 attached to the outer circumferential surface of the frame 3 . 7, a recess is formed on the outer periphery of the frame 3 as a packing mounting portion 35, and the packing 4 is fitted from the periphery into this packing mounting portion 35. In this state, the flaps 41, 42 protrude outward in the circumferential direction of the frame 3.

[0029] The frame 3 with the gasket 4 fitted in it is first attached to the upper case 1 with 16 screws 6 , and then fastened together with the upper case 1 and the lower case 2 with four more screws 5 .

[0030] A cross-sectional view of such a housing 10 is shown in Fig. 6. This is a cross-section in the FF direction of Fig. 1. The part circled by the dashed line in Fig. 6 is shown in an enlarged manner in Fig. 7.

[0031] The frame 3 is arranged so as to be fitted into the groove 11 provided in the upper case 1 and the groove 22 provided in the lower case 2. As a result, the flaps 41, 42 of the packing 4 attached to the packing attachment portion 35 are pressed against the inner surface of the housing 10. That is, the joint boundary 60 between the upper case 1 and the lower case 2 is positioned between the tip ends 41a, 42a of the flaps 41, 42, and the flap 41 is pressed against the upper case 1 and bends, and the flap 42 is pressed against the lower case 2 and bends. That is, as shown in FIG. 5, the flaps 41, 42 bend in a direction in which the space 50 inside the flap becomes narrower.

[0032] In this manner, the flaps 41, 42 are pressed against the upper case 1 and the lower case 2 from the inside by the frame 3, thereby generating the contact pressure necessary for waterproofing. The joint boundary 60 is then positioned so as to face the flap inner space 50 . Therefore, the entire periphery of the joint boundary 60, which may be susceptible to water ingress, faces the flap inner space 50, and this flap inner space 50 is sealed from the inside of the housing by the contact pressure of the flaps 41 and 42. This provides a sufficient waterproof function.

[0033] 7, the upper case 1 and the lower case 2 are fitted together with the protrusion 23 of the lower case 2 fitting into the recess 12 of the upper case 1, and then fastened with the screw 5. This increases the unity of the upper case 1 and the lower case 2, and the pressing force of the flaps 41, 42 is applied to the upper case 1 and the lower case 2 approximately evenly, so that excessive pressing force is not applied to either the upper case 1 or the lower case 2.

[0034] The above-described embodiment provides the following advantages. The waterproof structure of the embodiment includes a frame 3 (internal arrangement member) attached within the housing 10, which is formed by joining an upper case 1 and a lower case 2, and a ring-shaped packing 4 that can be arranged along a joint boundary 60 between the upper case 1 and the lower case 2. The frame 3 presses the packing 4 against the upper case 1 and the lower case 2 along the joint boundary 60.

[0035] In this structure, the gasket 4 is pressed by the frame 3 in a direction (left-right or front-back) different from the joining direction (up-down direction) of the upper case 1 and the lower case 2 when they are screwed together. Therefore, there is no need to place a large number of screws 5 at regular intervals to join the upper case 1 and the lower case 2, and the reduction in the number of screws visible on the exterior is preferable from the standpoint of design. In order to withstand the reaction force of the pressing of the packing 4, it is sufficient to use a large number of screws 5, 6 at appropriate intervals to secure the frame 3, and there is no need to particularly increase the joining strength between the upper case 1 and the lower case 2. Therefore, the screws 5 exposed from the housing 10 should only be at the four corners, and a large number of screws 6 that are not exposed should be used.

[0036] Furthermore, if the packing 4 were pressed by the upper case 1 and the lower case 2 instead of the frame 3, the contact portions of the packing 4 between the upper case 1 and the lower case 2 would need to have rigidity to withstand the reaction force against the pressing, and a certain degree of thickness would be required. In the case of this embodiment, such requirements are eliminated, which increases the freedom in the shape design and thickness size of the upper case 1 and the lower case 2, and also makes it difficult for sink marks to occur during resin molding when the case is made thicker, improving product quality.

[0037] In this embodiment, the packing 4 has a pair of flaps 41, 42 protruding from both edges (43, 44) of the base portion 40 shaped along the joint boundary 60. One flap 41 is pressed against the upper case 1, and the other flap 42 is pressed against the lower case 2. The flaps 41, 42 are pressed against the upper case 1 and the lower case 2 from the inside, causing the flaps 41, 42 to bend. In other words, the packing 4 does not compress the entire packing when it is pressed against the upper case 1 and the lower case 2, but rather causes the flaps 41, 42 to bend, thereby generating the contact pressure required for waterproofing.

[0038] This prevents the rigidity required for the upper case 1 and the lower case 2 from being excessive, and also enables a stable waterproof function to be maintained even in the event of size errors. That is, the flaps 41, 42 can increase the amount of protrusion from the base portion 40, absorbing any error in the distance from the frame 3 to the upper case 1 and the lower case 2, and a pressed-contact state can be obtained. Furthermore, when the flaps 41, 42 are deflected, the reaction force acting on the upper case 1 and the lower case 2 is smaller than when the entire case is compressed, and the rigidity required for the upper case 1 and the lower case 2 can be reduced.

[0039] In this embodiment, each of the flaps 41, 42 is shaped to protrude in a direction approaching the other flap as it approaches the tip end portions 41a, 42a. The flaps 41, 42 are pressed against the upper case 1 and the lower case 2 in a positional relationship in which they sandwich the line of the joint boundary 60 from above and below. The flap 41 is shaped to protrude from the upper edge 43 of the base portion 40 in a direction approaching the other flap 42 toward the tip 41a, and the flap 42 is shaped to protrude from the lower edge 44 of the base portion 40 in a direction approaching the other flap 41 toward the tip 42a. For this reason, when the flaps 41, 42 are pressed against the upper case 1 and the lower case 2, they bend toward the flap inner space 50.

[0040] This improves the waterproof function because the water pressure when water enters the case works to push up the flaps 41, 42, and the flaps 41, 42 are pressed against the upper case 1 and the lower case 2 more strongly by being pushed up.

[0041] In this embodiment, the frame 3 is fixed to the upper case 1 using screws 6 that are disposed inside the housing 10 and do not protrude to the outside of the housing. The frame 3 presses the packing 4, so the frame 3 bears the pressing reaction force, but the frame 3 is fixed to the upper case 1 by means of screws 6 that screw into the screw holes 33. The screws 6 are not exposed on the surface of the housing 10. By using a large number of such screws 6, the frame 3 can be properly fixed around the entire circumference of the packing 4, and can also be made to be able to withstand the reaction force of the packing 4.

[0042] The frame 3 includes a frame base 31 formed along the joint boundary 60 between the upper case 1 and the lower case 2, and the packing 4 is attached to the outer periphery of this frame base 31. The packing 4 is therefore pressed against the upper case 1 and the lower case 2 with a uniform pressure all around the joint boundary 60, providing a high level of waterproofing. The frame 3 is then fixed with a large number of screws 5 and 6 spaced at approximately equal intervals, which allows the pressure to be applied uniformly.

[0043] In other words, the design of the housing 10 is not marred by a large number of screws, and the waterproof function of the appropriate packing 4 can be maintained. Furthermore, by fastening the frame 3 with screws at a large number of points, the thickness required for rigidity can be reduced, making it suitable as an internal component of the housing 10.

[0044] In the embodiment, the method for manufacturing the gasket 4 includes a process for forming a string-like body by extrusion molding, and a process for generating functional groups that serve as the source of hydrogen bonds on both end surfaces of the string-like body and bonding them together by hydrogen bonding to form a ring shape. This allows the production of an annular packing without using adhesive.

[0045] The larger the housing is and the longer the overall perimeter of the joint boundary 60 is, the larger the annular packing becomes. In this case, if the packing is manufactured using a mold, the mold size becomes larger and only one piece is molded at a time, which is disadvantageous in terms of cost and manufacturing efficiency. In addition, it is difficult to mold an undercut shape such as the flaps 41 and 42. Therefore, the packing 4 of the embodiment is formed into a string-like shape having a base portion 40 and flaps 41, 42 by extrusion molding using a die. Then, the end faces of the string-like shape of a predetermined length are bonded together by hydrogen bonding without using adhesive to form a ring. This makes it possible to reduce manufacturing costs and improve manufacturing efficiency, and also makes it possible to manufacture the packing 4 having the flaps 41, 42. Furthermore, by not using adhesive, there is no overflow of adhesive on the bonding surface, and a ring-like body with a uniform surface can be formed, and high waterproof performance can be maintained.

[0046] The present invention is not limited to the transmitter housing 10 of the embodiment, but is suitable for various housings, particularly housings for electronic devices. Also, the present invention is not limited to a housing made up of upper and lower cases such as the upper case 1 and the lower case 2, but can be applied to a housing made up of a left case and a right case joined together, a housing made up of three or more case bodies joined together, etc.

[0047] Although the frame 3 has been exemplified as an internally disposed member, the internally disposed member may have any shape that corresponds to the joint boundary 60 of the housing. The shape of the packing 4 may also vary depending on the joint boundary 60 of the housing. [Explanation of symbols]

[0048] 1 Upper case 2 Lower case 3 Frame 4. Packing 5,6 Screws 10. Chassis 21,32,33 Screw holes 31 Frame base 35 Packing attachment part 40 Base 41,42 Flap 41a,42a Tip 43 Upper edge 44 Lower edge 50 Flap inner space 60 Junction boundary

Claims

1. In a housing formed by joining a plurality of case bodies, An internally disposed member attached within the housing; A ring-shaped packing that can be arranged along the joint boundaries of the plurality of case bodies; Equipped with The packing is pressed against the plurality of case bodies along the joint boundary by the internally disposed member. Waterproof construction of the housing.

2. The packing is The annular base portion has a pair of flaps protruding from one edge and the other edge of the annular base portion. A flap protruding from one edge portion is pressed against one of the case bodies to be joined, The flap protruding from the other edge portion is configured to be pressed against the other case body to be joined. The waterproof structure for a housing according to claim 1.

3. Each of the pair of flaps is shaped to protrude in a direction approaching the other flap as it approaches the tip side. The waterproof structure for a housing according to claim 2.

4. The internally disposed member is The housing is fixed to the case body using a screw inside the housing that is not exposed to the outside of the housing. The waterproof structure for a housing according to any one of claims 1 to 3.

5. forming a string-like body by extrusion molding; A step of forming functional groups that serve as the source of hydrogen bonds on both end surfaces of the string-like body and bonding the two ends by hydrogen bonds to form a ring is performed. Manufacturing method of packing.

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