Antenna for satellite navigation

Abstract

To provide an antenna for satellite navigation capable of properly preventing immersion of seawater or the like.SOLUTION: In the antenna for satellite navigation, a resin-made upper cover and a resin-made lower cover 22 are joined via a waterproof packing to constitute a housing, components including an antenna module are housed in the housing, and a metallic fixture 6 is attached to the 22a of the lower surface of the lower cover 22. A vent hole 22c penetrating the lower cover 22 is formed, a first water-immersion preventing cylinder 22d provided on a lower surface 22a of the lower cover 22 and extending downward in a cylindrical shape surrounding the vent hole 22c, and a second water-immersion preventing cylinder 22e provided on the lower surface 22a of the lower cover 22 and extending downward in a cylindrical shape surrounding the first water-immersion preventing cylinder 22d are provided, and a slit-shaped water drainage portion extending from a free end edge of the first water-immersion preventing cylinder 22d is formed on the first water-immersion preventing cylinder 22d.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a satellite navigation antenna for receiving signals from satellites. [Background technology]

[0002] For example, ships are equipped with satellite navigation antennas that receive signals from satellites in order to calculate and acquire information on the ship's heading, attitude, etc. This satellite navigation antenna has a housing made up of a resin upper cover and a lower cover joined together via waterproof packing, and this housing houses an antenna module, electronic components, etc.

[0003] Because such satellite navigation antennas are installed exposed outdoors, sudden temperature changes in the morning and evening can cause a pressure difference between the inside and outside of the housing, which can lead to seawater, rainwater, etc. being sucked into the housing through deteriorated (sagging) parts of the waterproof packing. For this reason, a method has been adopted in which ventilation holes are provided in the housing to eliminate the pressure difference between the inside and outside due to temperature changes. Furthermore, to prevent seawater and other water from entering through these ventilation holes, a technique is known in which waterproofing means such as an impermeable material or a labyrinth structure is provided in the ventilation holes (see, for example, Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 7-14677 Summary of the Invention [Problem to be solved by the invention]

[0005] However, waterproofing means made of impermeable materials not only take time to eliminate the internal and external pressure difference, but also have the risk of clogging due to aging and other factors. Furthermore, it is difficult to design ventilation holes in places that are not exposed to seawater, and even if waterproofing means with a labyrinth structure are installed, it is difficult to achieve a strict waterproofing rating (for example, IPX6 rating, which requires a water flow of 100 L / min from all directions over a surface area of ​​1 m2). 2 It is difficult to prevent flooding with specifications that state that there will be no flooding even if water is sprayed for one minute per unit, for a total of three minutes or more.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a satellite navigation antenna that can appropriately prevent ingress of water such as seawater. [Means for solving the problem]

[0007] In order to achieve the above object, the invention described in claim 1 is a satellite navigation antenna in which a housing is formed by joining a resin upper cover and a lower cover via a waterproof gasket, components including an antenna module are housed within the housing, and a metal fixing bracket is attached to the underside of the lower cover, wherein an air vent is formed through the lower cover, and the antenna is equipped with a first water-proof tube that is tubular and extends downward and is provided on the underside of the lower cover to surround the air vent, and a second water-proof tube that is tubular and extends downward and is provided on the underside of the lower cover to surround the first water-proof tube, and wherein the first water-proof tube is formed with a slit-shaped drain portion extending from the free edge of the first water-proof tube.

[0008] The invention described in claim 2 is characterized in that, in the satellite navigation antenna described in claim 1, an inclined portion is formed on the upper surface of the lower cover, which slopes downward toward the air vent.

[0009] The invention as set forth in claim 3 is characterized in that, in the satellite navigation antenna as set forth in claim 1, a waterproof wall is provided on the upper surface of the lower cover so as to surround the ventilation hole.

[0010] The invention as set forth in claim 4 is characterized in that, in the satellite navigation antenna as set forth in claim 3, the waterproof wall is formed with a notched drainage portion that allows water to pass through. [Effects of the Invention]

[0011] According to the invention described in claim 1, the air vent in the lower cover is surrounded by a first water-proof tube, which is in turn surrounded by a second water-proof tube. Therefore, for seawater or other water to enter the housing, it must first pass over the second water-proof tube and then the first water-proof tube to reach the air vent, thereby making it possible to properly and reliably prevent the ingress of seawater or other water. Furthermore, a drain is formed from the free edge of the first water-proof tube, making it possible to prevent seawater or other water from accumulating or adhering to the free end or open end of the first water-proof tube due to surface tension.

[0012] Furthermore, if seawater or other substances accumulate or adhere, without a drain, the water pressure from the explosive water current could push the seawater or other substances upward and cause it to seep in through the air vent. However, because a drain is provided, seawater or other substances flow from the drain to the outside of the first water-blocking tube. This makes it possible to prevent seawater or other substances from being pushed up and seeping in through the air vent. Meanwhile, because outside air is drawn into the housing via the second water-blocking tube, the first water-blocking tube, and the air vent, no pressure difference occurs between the inside and outside of the housing, preventing seawater or other substances from being sucked into the housing.

[0013] According to the invention described in claim 2, an inclined portion that descends toward the air vent is formed on the upper surface of the lower cover, so that even if seawater or the like seeps in through the air vent, the infiltrated seawater or the like can be made to flow from the inclined portion toward the air vent and drained out through the air vent.

[0014] According to the invention described in claim 3, a waterproof wall is provided on the upper surface of the lower cover to surround the ventilation hole, so that even if seawater or the like enters through the ventilation hole, it is possible to prevent the infiltrated seawater or the like from spreading inside the housing.

[0015] According to the invention described in claim 4, since a drainage section is formed in the waterproof wall, even if seawater or the like seeps into the housing through the waterproof gasket, the seeped seawater or the like can be drawn into the inside of the waterproof wall through the drainage section and drained through the air vent. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing an upper cover side of a satellite navigation antenna according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing the lower cover side of the satellite navigation antenna of FIG. 1. [Figure 3] 3 is an enlarged perspective view showing a first water-entering cylinder and a second water-entering cylinder in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the first water-entering cylinder and the second water-entering cylinder in FIG. 3 taken along a first vertical plane. FIG. [Figure 5] 4 is a cross-sectional view of the first water-entering cylinder and the second water-entering cylinder in a second vertical plane of FIG. 3. FIG. [Figure 6] 3 is a perspective view showing the periphery of the waterproof wall on the upper surface of the lower cover of FIG. 2. FIG. [Figure 7] FIG. 2 is a perspective view showing the satellite navigation antenna of FIG. 1 with the upper cover removed. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described below based on the illustrated embodiments.

[0018] 1 to 7 show an embodiment of the present invention, and Fig. 1 and Fig. 2 are perspective views showing the upper cover 21 side and the lower cover 22 side of a satellite navigation antenna 1 according to this embodiment. This satellite navigation antenna 1 is an antenna for receiving signals from satellites, and in this embodiment, it is assumed to be mounted on a ship.

[0019] This satellite navigation antenna 1 has a housing 20 formed by joining the outer peripheries of a resin upper cover 21 and a lower cover 22 via waterproof packing 3, and components including an antenna module 5 are housed inside this housing 20, with a metal fixing bracket 6 attached to the underside (outer surface) 22a of the lower cover 22. By fixing the fixing bracket 6 to the ship, the lower cover 22 is on the lower side and the upper cover 21 is on the upper side, and the entire antenna extends approximately horizontally and is installed on the ship.

[0020] That is, as shown in Fig. 1, upper cover 21 is made of a single-piece molded plastic, has a roughly three-pronged planar shape, has cylindrical portions 21a with hemispherical upper parts at each end, and has a dome-shaped hemispherical portion 21b in the center. Similarly, lower cover 22 is made of a single-piece molded plastic, has a roughly three-pronged planar shape, and has a connector portion 22b for connecting a cable in the center, as shown in Fig. 2.

[0021] 7, a three-pronged base 4 made of sheet metal is attached to the upper surface (inner surface) of the lower cover 22. Each tip of this base 4 rises upward, and an antenna module 5 is disposed on each mounting plate portion 41 at the upper end, and a processing unit (arithmetic unit) 40 is disposed in the center of the base 4.

[0022] Meanwhile, string-like waterproof packing 3 is arranged along the outer periphery of lower cover 22, and upper cover 21 is placed over lower cover 22 and joined (bolted) to join upper cover 21 and lower cover 22 via waterproof packing 3 to form housing 20. In this state, antenna modules 5 are housed in the tops of the three cylindrical portions 21a, respectively, and processing unit 40 is housed in hemispherical portion 21b.

[0023] In the housing 20 sealed in this manner, as shown in Figures 3 to 5, an air vent 22c, a first water-blocking tube 22d, and a second water-blocking tube 22e are provided in the center of the lower cover 22.

[0024] The ventilation holes 22c are holes that penetrate the lower cover 22, and the size, area and number of the ventilation holes 22c are set so that seawater and the like are unlikely to penetrate into the housing 20, and so that outside air is taken into the housing 20 and no pressure difference occurs between the inside and outside of the housing 20.

[0025] The first water-entry prevention cylinder 22d is a cylinder that surrounds the air vents 22c and is molded integrally with the lower cover 22 so as to extend downward from the underside 22a of the lower cover 22. The inner diameter of the first water-entry prevention cylinder 22d is set to a size that can surround all of the air vents 22c and to prevent seawater and other liquids from seeping in. The axial length of the first water-entry prevention cylinder 22d is set to prevent seawater and other liquids from seeping in from the open end toward the air vents 22c.

[0026] 3 and 4, the first water-entry prevention cylinder 22d is formed with a slit-shaped drain section 22f extending from its free edge. This drain section 22f has a predetermined width and extends from the free edge of the first water-entry prevention cylinder 22d toward the air vent 22c, and its width and length are set so that seawater and the like that has accumulated or adhered to the free end and open end of the first water-entry prevention cylinder 22d can be drained to the outside of the first water-entry prevention cylinder 22d.

[0027] In other words, if there were no drain section 22f, seawater or the like that has accumulated or adhered to the free end and open end of first water-entering cylinder 22d would be pushed up by the water pressure of the explosive water current and could seep through vent hole 22c into housing 20. For this reason, the width and length of drain section 22f are set so that seawater or the like that has accumulated or adhered to the free end and open end of first water-entering cylinder 22d can flow from drain section 22f to the outside of first water-entering cylinder 22d.

[0028] The second water-entry prevention cylinder 22e is a cylindrical body that surrounds the first water-entry prevention cylinder 22d and is molded integrally with the lower cover 22 so as to extend downward from the underside 22a of the lower cover 22. The inner diameter of the second water-entry prevention cylinder 22e is larger than the outer diameter of the first water-entry prevention cylinder 22d and is set so that seawater and the like do not easily penetrate into the first water-entry prevention cylinder 22d. The axial length of the second water-entry prevention cylinder 22e is set so that the free end of the second water-entry prevention cylinder 22e protrudes beyond the free end of the first water-entry prevention cylinder 22d, thereby making it difficult for seawater and the like to penetrate into the first water-entry prevention cylinder 22d.

[0029] The first water-entry prevention cylinder 22d and the second water-entry prevention cylinder 22e are formed coaxially. Note that, although this embodiment has been described with the first water-entry prevention cylinder 22d and the second water-entry prevention cylinder 22e being cylindrical, they may be tubular in shape other than cylindrical depending on the surrounding shape, components, etc.

[0030] 5 and 6, an inclined portion 22g that slopes downward toward the ventilation hole 22c is formed on the upper surface of the lower cover 22. This inclined portion 22g is a portion that is located around the ventilation hole 22c on the upper and inner surfaces of the lower cover 22, and is formed so as to slope downward toward the ventilation hole 22c so that seawater and the like that accumulates or adheres to this inclined portion 22g flows toward the ventilation hole 22c. The area and size of this inclined portion 22g are set to an area where seawater and the like that has entered through the ventilation hole 22c and the like can accumulate or adhere.

[0031] Furthermore, a waterproof wall 22h is provided on the upper surface of lower cover 22 so as to surround ventilation hole 22c. This waterproof wall 22h is a barrier to prevent seawater and the like that has entered through ventilation hole 22c from spreading inside housing 20, and it rises from the upper surface of lower cover 22, extends in a ring shape (in this embodiment, a rectangle with rounded corners) so as to surround ventilation hole 22c, and is molded integrally with lower cover 22. The area and size of this waterproof wall 22h are set within inclined portion 22g (smaller than inclined portion 22g) and to an area that seawater and the like that has entered through ventilation hole 22c can reach, taking into consideration the surrounding shape, components, and the like.

[0032] This waterproof wall 22h is formed with a plurality of notched drainage sections 22k that allow water to pass through. These drainage sections 22k are passages that allow seawater and other water that has seeped in through the waterproof packing 3 to be drawn into the waterproof wall 22h and to be discharged through the air vents 22c, and are formed by cutting out a portion of the waterproof wall 22h to provide a gap. The width, position, and number of these drainage sections 22k are set so that seawater and other water that has seeped in through the waterproof packing 3 can be reliably drawn into the waterproof wall 22h, and so that seawater and other water within the waterproof wall 22h is less likely to flow out of the waterproof wall 22h. In this embodiment, one drainage section 22k is formed on each of the two short sides of the substantially rectangular waterproof wall 22h.

[0033] Additionally, a plurality of bolt holes (screw holes) for attaching the fixing bracket 6 are formed in the underside 22a of the lower cover 22. Meanwhile, a plurality of bolt insertion holes are formed in the fixing bracket 6, and by inserting bolts into the bolt insertion holes and tightening them, the fixing bracket 6 is attached to the underside 22a of the lower cover 22, as shown in Fig. 2. In this state, a hole is formed in the fixing bracket 6 to allow the second water entry prevention tube 22e to pass through, so that the first water entry prevention tube 22d and the second water entry prevention tube 22e are exposed to the outside.

[0034] In the satellite navigation antenna 1 configured as described above, the air vent 22c of the lower cover 22 is surrounded by the first water-proof tube 22d, which is in turn surrounded by the second water-proof tube 22e. Therefore, for seawater or the like to enter the housing 20, it must first pass over the second water-proof tube 22e and then over the first water-proof tube 22d to reach the air vent 22c, thereby making it possible to properly and reliably prevent the intrusion of seawater or the like. Furthermore, because the drain 22f is formed from the free edge of the first water-proof tube 22d, it is possible to prevent seawater or the like from accumulating or adhering to the free end / open end of the first water-proof tube 22d due to surface tension.

[0035] Furthermore, if seawater or other liquids accumulate or adhere to the free end or open end of first water-entering cylinder 22d, without drain 22f, the water pressure from the explosive water current would push the seawater or other liquids upward and risk infiltrating through vent 22c. However, because drain 22f is provided, seawater or other liquids flow from drain 22f to the outside of first water-entering cylinder 22d. This makes it possible to prevent seawater or other liquids from being pushed upward and infiltrating through vent 22c into housing 20. Meanwhile, because outside air is drawn into housing 20 via second water-entering cylinder 22e, first water-entering cylinder 22d, and vent 22c, no pressure difference occurs between the inside and outside of housing 20, preventing seawater or other liquids from being sucked into housing 20.

[0036] In addition, since an inclined portion 22g that descends toward the ventilation hole 22c is formed on the upper surface of the lower cover 22, even if seawater or the like seeps in through the ventilation hole 22c, the infiltrated seawater or the like can be made to flow from the inclined portion 22g toward the ventilation hole 22c and be drained from the ventilation hole 22c.

[0037] Furthermore, a waterproof wall 22h is provided on the upper surface of the lower cover 22 so as to surround the ventilation hole 22c, so that even if seawater or the like seeps in through the ventilation hole 22c, it is possible to prevent the inundated seawater or the like from spreading inside the housing 20.

[0038] Furthermore, since the water-repellent wall 22h is formed with a drainage section 22k, even if seawater or the like seeps into the housing 20 through the waterproof packing 3, the seeping seawater or the like can be drawn into the inside of the water-repellent wall 22h through the drainage section 22k and drained through the ventilation hole 22c.

[0039] Although the embodiments of the present invention have been described above, the specific configuration is not limited to the above embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. For example, in the above embodiments, the air vent 22c, the first water entry prevention cylinder 22d, and the second water entry prevention cylinder 22e are provided in positions where the fixing bracket 6 overlaps, but they may also be provided in positions where they do not overlap. [Explanation of symbols]

[0040] 1. Satellite navigation antenna 20 Case 21 Upper cover 22 Lower cover 22a Bottom side 22c Ventilation hole 22d First flood prevention tube 22e Second flood protection tube 22f Draining section 22g inclined part 22h waterproof wall 22k drainage section 3 Waterproof packing 5 Antenna Module 6 Fixing bracket

Claims

1. A satellite navigation antenna comprising a housing formed by joining a resin upper cover and a lower cover via a waterproof packing, components including an antenna module housed in the housing, and a metal fixing bracket attached to the underside of the lower cover, A vent hole is formed through the lower cover, a first water-blocking tube that is provided on the underside of the lower cover, surrounds the ventilation hole, and extends downward; a second water-blocking tube that is provided on the underside of the lower cover, surrounds the first water-blocking tube, and extends downward; wherein the first water-blocking cylinder is formed with a slit-shaped drain portion extending from a free edge of the first water-blocking cylinder.

2. An inclined portion that slopes downward toward the ventilation hole is formed on the upper surface of the lower cover.

2. The satellite navigation antenna according to claim 1.

3. A waterproof wall is provided on the upper surface of the lower cover so as to surround the ventilation hole.

2. The satellite navigation antenna according to claim 1.

4. The waterproof wall has a notched drainage section through which water passes.

4. The satellite navigation antenna according to claim 3.

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