JP7159783B2 - Waterproof structure of case material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a waterproof structure for a case member of a vehicle display device or the like.

2. Description of the Related Art Conventionally, a waterproof structure is known in which a set of cases is fixed with screws via a waterproof packing. The waterproof packing is inserted into the body of the screw and placed between the head of the screw and the case. The screw is tightened while compressing the waterproof packing via the head, thereby imparting waterproofness to the screwed portion.

Japanese Unexamined Patent Application Publication No. 2010-32470

When the screw is tightened, the waterproof packing, which is in contact with the head, receives frictional resistance as the head rotates and twists. Depending on the size of the waterproof packing, such as when the waterproof packing is thick, this twisting may cause shearing of the waterproof packing, which may reduce the waterproof performance of the waterproof structure.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a waterproof structure for a case member that can reduce deterioration in waterproofness during assembly work.

In order to solve the above-described problems, a waterproof structure for a case member according to the present invention provides a head, a body connected to the head, and a body provided between the head and the body. a stepped portion having an outer diameter smaller than the outer diameter of the body portion and larger than the outer diameter of the body; and insertion of the screw having an inner diameter larger than the head and supporting the head. a first recess having a first support surface perpendicular to the direction of the insertion; and a first recess provided on the far side in the insertion direction of the first recess and having an outer diameter smaller than the outer diameter of the head and larger than the inner diameter of the stepped portion. a second recess having a second support surface orthogonal to the insertion direction and accommodating the stepped portion; a case member fixed to an object; supported by the second support surface in a state of being compressed by the screw through the stepped portion; 2, a sealing member for waterproofing the back side in the insertion direction from the supporting surface.

In the waterproof structure of the case member according to the present invention, it is possible to reduce deterioration in waterproofness during assembly work.

1 is a front view of a display device to which a waterproof structure of a case member according to the present invention is applied; FIG. Rear view of the display device. Sectional drawing which follows the III-III line of FIG.

An embodiment of a waterproof structure for a case member according to the present invention will be described with reference to the accompanying drawings. The waterproof structure of the case member according to the present invention can be applied, for example, to display devices mounted on vehicles such as automobiles and motorcycles, ships, agricultural machinery, and construction machinery. An example in which the waterproof structure of the present embodiment is applied to a vehicle display device will be described below.

FIG. 1 is a front view of a display device 1 to which a waterproof structure of a case member according to the present invention is applied.
FIG. 2 is a rear view of the display device 1. FIG.
FIG. 3 is a cross-sectional view taken along line III--III in FIG.

In the following description, "front (front)", "back (back)", "upper", "lower", "right", and "left" are defined as "Fr." Re.", "To.", "Bo.", "R", and "L".

The display device 1 mainly has a case 10 , a display unit 20 and a circuit board 30 .

The case 10 has a lower case (case member) 11 , an upper case 12 and a middle case 13 .

The lower case 11 and the upper case 12 are made of black resin (for example, polypropylene). The lower case 11 is fixed to the upper case 12 with screws 50 using the waterproof structure 2, which will be described later. Thereby, the lower case 11 and the upper case 12 form an internal space, and the display unit 20 and the circuit board 30 are accommodated in this internal space.

The upper case 12 has an opening 12a covered with a transparent plate 15 . The translucent plate 15 is a flat plate provided to protect the display unit 20 and the circuit board 30 inside the case 10 from dust and the like. The translucent plate 15 has a transmissive area in an area corresponding to the display area of the display panel 21 of the display unit 20, and has a light shielding area in an area other than the transmissive area. This allows the viewer to visually recognize the display area of the display panel 21 located on the rear side.

The middle case 13 is made of white synthetic resin (for example, polypropylene), and fixes and supports the display unit 20 and the circuit board 30 in the internal space of the case 10 .

The display unit 20 has a display panel 21 and a backlight unit (not shown).

The display panel 21 is a TFT (Thin Film Transistor) liquid crystal display panel of a normally black type (black display when no voltage is applied). The display panel 21 has a pair of surface glass substrates enclosing a liquid crystal layer. Transparent electrodes of ITO (Indium Tin Oxide) or the like are formed on the pair of glass substrates. The display panel 21 also has a pair of surface polarizing plates (polarizing filters) arranged to sandwich the pair of surface glass substrates. The display panel 21 is connected to the circuit board 30 via FPCs (Flexible Printed Circuits). The display panel 21 is controlled by the control section of the circuit board 30 so that a driving voltage is applied to the liquid crystal layer through the transparent electrodes. As a result, the orientation of liquid crystal molecules in the liquid crystal layer is controlled, and an image is displayed by changing the transmittance of each pixel of the display panel 21 .

The backlight unit is provided on the back side of the display panel 21 . The backlight unit consists of a light source substrate and a light guide, and illuminates the display panel 21 from the rear side. The light source substrate mounts a plurality of LEDs (Light Emitting Diodes), which is an example of a light source. The light source board is connected to the circuit board 30 via a flexible board such as FPC. When a drive current is supplied to the LED, the LED emits light toward the display panel 21 (light guide). The light guide guides the light emitted by the LED toward the display panel 21 . The light guide is a transparent resin (for example, polymethyl methacrylate resin (PMMA)) formed in a flat plate shape.

The circuit board 30 mainly has a control section for controlling the display unit 20 . The control unit has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and executes predetermined arithmetic processing according to a program written in the ROM, for example. The control unit acquires, for example, vehicle speed, engine speed, various vehicle information, navigation information, and the like from an ECU (Electronic Control Unit) of the vehicle via various sensors and the like. The control unit causes the display unit 20 to display information based on the acquired information.

Next, the waterproof structure 2 used when fixing the lower case 11 and the upper case 12 with screws 50 will be described. The waterproof structure 2 may be applied to all locations where the screws 50 shown in FIG. 2 are provided, or may be applied only to necessary locations.

As shown in FIG. 3 , the waterproof structure 2 includes a screw 50 , a lower case 11 as an outer case, an upper case 12 as an object, and a waterproof packing (sealing member) 60 .

The screw 50 has a head portion 51 , a body portion 53 and a stepped portion 55 . The screw 50 has a head portion 51, a stepped portion 55, and a body portion 53 in order along the insertion direction of the screw 50 (from the rear to the front).

The head portion 51 is exposed from the back surface 11 a of the lower case 11 and is a flat plate-shaped flange portion for the body portion 53 . The head 51 has a groove- or hole-like operating recess 52 for turning and tightening the screw 50 with a tool.

The body portion 53 is connected substantially perpendicularly to the head portion 51 . The trunk portion 53 has a screw portion that is helically threaded on the end side opposite to the connection end.

The stepped portion 55 is provided between the head portion 51 and the body portion 53 . The step portion 55 has an outer diameter Db that is smaller than the outer diameter Da of the head portion 51 and larger than the outer diameter Dc of the body portion 53 (Da>Db>Dc).

The lower case 11 has a through hole 70 for passing the screw 50 therethrough. The through hole 70 has a first recess 71 , a second recess 73 and a third recess 75 . The through-hole 70 has a first recess 71 , a second recess 73 , and a third recess 75 in sequence along the insertion direction of the screw 50 . The lower case 11 is fixed to the upper case 12 (object) with the screws 50 by inserting the screws 50 into the first recess 71 , the second recess 73 and the third recess 75 .

The first recess 71 has an inner diameter D<b>1 that is larger than the outer diameter Da of the head 51 . The first concave portion 71 is a concave portion with respect to the back surface 11 a of the lower case 11 . The first recess 71 has a first support surface 72 perpendicular to the insertion direction of the screw 50 . The first recess 71 supports the head 51 with the first support surface 72 .

The second recessed portion 73 is provided on the far side in the insertion direction from the first recessed portion 71 . The second recessed portion 73 has an inner diameter D2 (Da>D2>Db) that is smaller than the outer diameter Da of the head portion 51 and larger than the outer diameter Db of the stepped portion 55 . The second recessed portion 73 is a recessed portion with respect to the first support surface 72 . The second recess 73 has a second support surface 74 orthogonal to the insertion direction. The second recess 73 supports the waterproof packing 60 with the second support surface 74 . Also, the second recess 73 accommodates the stepped portion 55 without being in contact with the stepped portion 55 .

The third recessed portion 75 is provided on the far side in the insertion direction from the second recessed portion 73 . The third recess 75 has an inner diameter D3 (Dp>D3>Dc) that is smaller than the outer diameter Dp of the waterproof packing 60 and larger than the outer diameter Dc of the trunk portion 53 . The third recessed portion 75 is a recessed portion from the second support surface 74 .

The upper case 12 has a screw cylinder portion 80 at a position corresponding to the through hole 70 of the lower case 11 . The screw cylinder portion 80 has a cylindrical shape integrally formed with the upper case 12 so as to protrude toward the lower case 11 (toward the rear side). The screw cylinder part 80 has an insert nut 81 inside. The insert nut 81 is provided by insert molding and has a threaded hole 82 corresponding to the screw 50 .

The waterproof packing 60 is an annular member made of black synthetic rubber, and waterproofs the back side of the second support surface 74 in the insertion direction. The waterproof packing 60 has an outer diameter Dp that is larger than the outer diameter Db of the stepped portion 55 and smaller than the inner diameter D2 of the second recess 73 . The waterproof packing 60 has an outer diameter Dp (D2>Dp>Db>D3) larger than the inner diameter D3 of the third recess 75. As shown in FIG. Moreover, the waterproof packing 60 has an inner diameter that allows it to be inserted into the trunk portion 53 and has as little a gap as possible with respect to the trunk portion 53 . The waterproof packing 60 is supported by the second support surface 74 while being in contact with the stepped portion 55 and compressed by the screws 50 .

Next, the effect of screwing the lower case 11 and the upper case 12 to obtain the waterproof structure 2 will be described. In the following description, when the lower case 11 and the upper case 12 are screwed together, the middle case 13 is tightened together through the fixing hole 14 of the middle case 13 .

First, the upper case 12 is placed as a reference so that the position of the insert nut 81 of the upper case 12, the position of the fixing hole 14 of the middle case 13, and the through hole 70 of the lower case 11 are aligned. At this time, the packing 18 is fitted into the space formed by the ends 11b and 12b of the lower case 11 and the upper case 12, which are the abutting portions. As a result, the peripheral edges of the lower case 11 and the upper case 12 are kept watertight.

Next, with the waterproof packing 60 attached to the body portion 53 of the screw 50 , the body portion 53 of the screw 50 is inserted into the through hole 70 of the lower case 11 . By applying a tool to the operation concave portion 52 of the head portion 51 and turning the screw 50 to tighten it, the body portion 53 is stopped in the screw hole 82 provided in the insert nut 81 of the upper case 12 . As a result, the lower case 11, the upper case 12 and the middle case 13 are fastened together.

In such a waterproof structure 2, the entire back surface 60b of the waterproof packing 60, which is the surface facing the head portion 51, does not come into contact with the screw 50 when screwed. That is, since the screw 50 has the stepped portion 55 having the outer diameter Db smaller than the outer diameter Da of the head portion 51, the contact area between the back surface 60b of the waterproof packing 60 and the screw 50 can be reduced. As a result, frictional resistance between the screw 50 and the waterproof packing 60 can be reduced during tightening, and twisting and breakage of the waterproof packing 60 can be reduced.

Also, the outer diameter Dp of the waterproof packing 60 is smaller than the inner diameter D2 of the second recess 73 . Therefore, the wall surface 73a of the second concave portion 73 and the waterproof packing 60 are not in contact with each other during tightening, and the waterproof structure 2 can further reduce twisting of the waterproof packing 60 .

Furthermore, the through-hole 70 has a third recess 75 in order to reduce the area of the second support surface 74 that contacts and supports the front surface 60a of the waterproof packing 60 (opposite surface of the back surface 60b). Therefore, the contact area between the front surface 60a of the waterproof packing 60 and the second support surface 74 can be reduced. Therefore, the waterproof structure 2 can further reduce twisting of the waterproof packing 60 .

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

For example, the object to which the outer case (lower case 11) is fixed is not limited to another case (upper case 12), and may be a heat sink or a display unit.

1 display device 2 waterproof structure 10 case 11 lower case (case member)
11a back surface 11b end 12 upper case 13 middle case 12a opening 12b end 15 translucent plate 18 packing 20 display unit 21 display panel 30 circuit board 31 fixing hole 50 screw 51 head 52 operation recess 53 body 55 step 60 waterproof Packing (sealing material)
60a front surface 60b rear surface 70 through hole 71 first recess 72 first support surface 73 second recess 73a wall surface 74 second support surface 75 third recess 80 screw cylinder 81 insert nut 82 screw hole
Da, Db , Dc, Dp outer diameter
D1, D2, D3 inner diameter

Claims (3)

a head portion, a trunk portion connected to the head portion, and an outer diameter provided between the head portion and the trunk portion that is smaller than the outer diameter of the head portion and larger than the outer diameter of the trunk portion. a screw having a shoulder;
a first recess having an inner diameter larger than that of the head and having a first support surface perpendicular to the insertion direction of the screw that supports the head; a second recess having an inner diameter smaller than the outer diameter of the head portion and larger than the outer diameter of the stepped portion, having a second support surface perpendicular to the insertion direction, and accommodating the stepped portion; a case member that is fixed to an object by the screws by inserting the screws into the first recess and the second recess;
It is supported by the second supporting surface in a state of being compressed by the screw through the stepped portion, has an outer diameter larger than the outer diameter of the stepped portion, and is waterproof on the far side in the insertion direction from the second supporting surface. A waterproof structure for a case member, comprising: a sealing member that 2. The waterproof structure for a case member according to claim 1, wherein said sealing member has an outer diameter smaller than an inner diameter of said second recess. 3. The case member further comprises a third recess provided on the back side in the insertion direction of the second recess and having an inner diameter smaller than an outer diameter of the seal member and larger than an outer diameter of the body. 2. The waterproof structure of the case member according to 1.

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