On-vehicle rod antenna device

Abstract: An on-vehicle rod antenna device comprises an antenna rod, and an antenna base comprising a joint section to which the antenna rod is connected, in which the joint section comprises a tip portion, the tip portion is covered with the antenna rod in a state of connecting the antenna rod, and a substantially hemisphere recess or salient engaging with an inner circumferential surface of the antenna rod is formed on an outer circumferential surface of the tip portion.

Description: The present invention relates to an on-vehicle rod antenna device. FIG. 1A is a figure which shows an external configuration of the conventional on-vehicle rod antenna device. The rod antenna device 10 is constructed such that the antenna rod 13 is screwed and attached to the joint assembly 12 rotatably provided on the antenna base 11 mounted on the vehicle as shown in FIG. 1A. FIG. 1B is a figure which shows an external configuration of the joint assembly 12, especially, in a state of detaching the antenna rod 13. In FIG. 1B, the antenna rod cover 13a forms the outer surface of the above-mentioned antenna rod 13. A tip portion of the joint assembly 12 is covered with the antenna rod cover 13a by attaching the antenna rod 13. The plurality of hexahedron-shaped the projections 12b (for example, at 4 portions) made of the resin with the ABS resin etc. is radially formed, along outer circumferential surface of the metal cylindrical body 12a screwed at inner circumferential surface on an tip portion of the joint assembly 12. FIG. 1C shows an outline view of the joint assembly 12. A size of the outside diameter at the end surface position of the outer circumferential surface of each the projections 12b is set slightly larger than a size of the inside diameter of this contact portion of the antenna rod cover 13a with the corresponding elasticity. When screwing and attaching the antenna rod 13 to mount it on the joint assembly 12, the inner surface of the antenna rod cover 13a is pushed by the projections 12b and transformed with elasticity. Thereby, the antenna rod 13 is prevented from loosening and departing from the joint assembly 12 by the outside power such as the vibrations. That is, the projections 12b of the joint assembly 12 are formed as a stopper of the antenna rod 13 loosening to the vibration, etc. of the vehicle where the on-vehicle rod antenna device 10 is attached. In the antenna rod 13 attached on the joint assembly 12, the installation metal fittings (not shown in the figure) with a tip portion which screws to the above-mentioned cylindrical body 12a in cylindrical bottom of the antenna rod cover 13a are laid underground. Then, the antenna rod element (not shown in the figure) is drawn out and undergrounded to the axis portion of the antenna rod cover 13a so as to be connected with this installation metal fittings. The outside diameter at the outer circumferential surface position of the projections 12b of the joint assembly 12 is set larger than the inside diameter at the position where the antenna rod cover 13a of the corresponding antenna rod 13 corresponds as mentioned above. By screwing the installation metal fittings of the antenna rod 13 to the cylindrical body 12a of the joint assembly 12, when the antenna rod 13 is connected with the joint assembly 12, The projections 12b transform the antenna rod 13 by the elasticity of the antenna rod cover 13a and the frictional force corresponding to the elasticity power is given to the inner surface of the antenna rod cover 13a. As a result, the antenna rod 13 is prevented from loosening from the joint assembly 12 by the vibration of the vehicle etc. Therefore, since the locking effect of the projections 12b of the joint assembly 12 changes greatly according to largeness of elasticity of antenna rod cover 13, largeness of friction with inside of the antenna rod cover 13, the outside diameter at the outer circumferential surface position and a size of the antenna rod cover 13a inside diameter. A very small allowance is required at the manufacturing, there is a disadvantage of raising the manufacturing cost as a result. In addition, when the outer circumferential surface of the projections 12b wear out by repeating the attaching/detaching of the antenna rod 13 to the joint assembly 12, an initial locking effect is lost at once. In EC safety standard (European safety standard), so that the projection object mounted on the car may never give the person harm, even the state of detaching the antenna rod 13, it is a reference that all positions where the human body may be contacted to the joint assembly 12 have the roundness of R 2.5 mm or more (5 mm or more in the diameter) and the small R and the corner of less than R 2.5 mm are prohibited. However, the cylindrical body 12a and the projections 12b of the joint assembly 12 and the neighborhood thereof have small R and the corner of less than R 2.5 mm as seen from FIG. 1C. Therefore, it is not possible to agree with the above-mentioned EC safety standard. An object of the present invention is to provide an on-board rod antenna device in which a sufficient locking effect can be maintained for a long period without requiring a sever size accuracy in manufacturing, and a pointed component is not exposed to an outside, where the human body may be contacted, even in a state of detaching the antenna rod. EP-A-0 800 226 discloses an antenna comprising a tube-shaped flange and a coupling set at an angle of 90 degrees. A sleeve continues upward and accommodates the wire, while the flange possesses a circumferential groove for catching in a recess, with a double undercut, in the housing. The flange is made with a slot for locating in the recess to prevent radial play, and the sleeve is made of flexible material. WO 99 13530 A discloses a dual band frequency antenna adapted for panel mounting, which may be mounted to a vehicle and which includes an inner conductive element in the form of an elongated rod and an outer conductive element in the form of a conductive sleeve. The rod is connected to a base portion. WO 99 48167 A discloses an antenna device which may be attached to an automobile by magnetic fastening means, the antenna comprising a rod portion which is screwed to a base portion. The present invention provides a rod antenna device as set out in appended claim 1. The invention can be more fully under stood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1A to FIG. 1C are figures which show the external configuration etc. of the conventional on-vehicle rod antenna device; FIG. 2A to FIG. 2C are figures which show the external configuration etc. of the on-vehicle rod antenna device according to the embodiment of the present invention; and FIG. 3 is a sectional view which shows especially a connection structure of the joint assembly and the antenna rod in FIG. 2A to FIG. 2C. Hereinafter, the on-vehicle rod antenna device according to the embodiment of the present invention will be explained referring to the drawings. FIG. 2A shows an external configuration of the on-vehicle rod antenna device according to the embodiment of the present invention. In FIG. 2A, the on-vehicle rod antenna device 20 is constructed by screwing and attaching the antenna rod 23 to the joint assembly 22 rotatably provided to the antenna base 21 mounted on the vehicle. FIG. 2B is a figure which shows an external configuration of the joint assembly 22, especially, in a state of detaching the antenna rod 23. The antenna rod cover 23a forms the outer surface of the above-mentioned the antenna rod 23, and is a cover made of, for example, the resin having elasticity such as rubber and the elastomer resin. Tip portion 22a of the joint assembly 22 is covered with the antenna rod cover 23a by attaching the antenna rod 23. The plurality of (for example, four) substantially hemisphere salients 22b are radially formed about along the outer circumferential surface of the tip portion 22a of the joint assembly 22. FIG. 2C shows outline view of the joint assembly 22. The salients 22b are made of, for example, the resin with the ABS resin etc. and are formed with the tip portion 22a as one body. The recesses 23b are formed to be engaged with the salients 22b at the inner circumferential surface of the antenna rod cover 23a corresponding to the salients 22b in a state that the above-mentioned antenna rod 23 is screwed and attached on the joint assembly 22. That is, a side where the recesses 23b of the antenna rod cover 23a are formed is moved along axial direction by properly transforming by the elasticity of the salients 22b formed in the outer circumference of the tip portion 22a of the joint assembly 22, when screwing and attaching the antenna rod 23 to the joint assembly 22. The antenna rod 23 engages with the salients 22b formed on the outer circumferential surface of the tip portion 22a when the recesses 23b reaches a predetermined position of the joint assembly 22. As a result, the antenna rod 23 is set to the state that the transformation by elasticity is released. When the antenna rod 23 is loosened to detach the antenna rod 23 from the joint assembly 22 in the state that the recesses 23b of the antenna rod cover 23a engages with the salients 22b of the tip portion 22a, it is necessary to transform the antenna rod cover 23a again by the elasticity by the salients 22b of the tip portion 22a. Therefore, the antenna rod 23 is not detached from the joint assembly 22 by loosening by the outside power such as the vibrations of the vehicle where the on-vehicle rod antenna device 20 according to this embodiment is attached, since resistance is generated for loosening the antenna rod 23. FIG. 3 is a sectional view to explain the screw attachment structure of the above-mentioned joint assembly 22 and the antenna rod 23. The cylindrical joint section 22c which is screwed at inner surface thereof is laid underground at the center of the tip portion 22a made of the resin so as not to be exposed from the tip surface of the tip portion 22a for the upper portion of the joint assembly 22 as shown in FIG. 3. The locking salients 22b are formed on the outer circumferential surface on the tip portion 22a as one body. On the other hand, the clamp 23c in which the screw section which screws the joint section 22c is formed to the point thereof is undergrounded in cylindrical bottom of the antenna rod cover 23a. The antenna rod element 23d is drawn out and is undergrounded in the axis section of the antenna rod cover 23a to connect with the clamp 23c. Therefore, when the clamp 23c of the antenna rod 23 is screwed to the joint section 22c of the joint assembly 22 to attach the antenna rod 23 to the joint assembly 22, the point of the attached side of the antenna rod cover 23a of the antenna rod 23 is properly transformed by the elasticity by the salients 22b provided on the outer circumferential surface of the tip portion 22a of the joint assembly 22. The antenna rod cover 23a moves along the axial direction thereof while the resistance is generated. The transformation by the above-mentioned elasticity is released if the recesses 23b is engaged with the salients 22b formed on the outer circumferential surface of the tip portion 22a of the joint assembly 22, when the recesses 23b formed in the antenna rod cover 23a reaches even a predetermined position to the joint assembly 22. When the antenna rod 23 is loosened to detach the antenna rod 23 from the joint assembly 22 in the state that the recesses 23b of the antenna rod cover 23a engages with the salients 22b of the tip portion 22a, it is necessary to transform the antenna rod cover 23a again by the elasticity by the salients 22b of the tip portion 22a. Therefore, since resistance is generated for loosening the antenna rod 23. Therefore, the antenna rod 23 is not detached from the joint assembly 22 by loosening by the outside power such as the vibrations of the vehicle where the on-vehicle rod antenna device 20 according to this embodiment is attached. Therefore, a sufficient locking effect can be achieved. As described above, the locking effect can be achieved by engagement of the recesses 23b formed on the inner circumferential surface of the antenna rod cover 23a of the joint assembly 22 and the salients 22b provided on the outer circumferential surface if the tip portion 22a the antenna rod 23. In addition, since each shape thereof has a substantially comparatively large hemisphere, it becomes possible to maintain a sufficient locking effect for a long period without requiring a sever size accuracy. The entire surface of the tip portion 22a of the joint assembly 22 can be shaped to have sufficient large roundness, especially as shown in FIG. 2C. The joint section 22c which is the clamp is constructed to prevent from projecting to the surface. Therefore, a sufficient safe structure can be obtained, since a pointed component is not exposed outside where the human body may be contacted, even in the state of detaching the antenna rod 23 from the joint assembly 22. In the above-mentioned embodiment, the embodiment in which the substantially hemisphere salients 22b are provided on the joint assembly 22 and the recesses 23b are provided to the antenna rod 23 of the antenna rod 23 is explained, but the present invention is not limited to the embodiment. For example, the recesses may be provided on the joint assembly 22 and the salient may be provided on the antenna rod 23. The on-vehicle rod antenna device according to the above-mentioned embodiment of the present invention is characterized by comprising: an antenna rod; and an antenna base comprising a joint section to which the antenna rod is connected, in which the joint section comprises a tip portion, the tip portion is covered with the antenna rod in a state of connecting the antenna rod, and a substantially hemisphere recess or salient engaging with an inner circumferential surface of the antenna rod is formed on an outer circumferential surface of the tip portion. As mentioned above, the locking effect can be achieved by the engagement of a comparatively large substantially hemisphere salients and recesses formed on the tip portion of the joint section and the inner circumferential surface of the antenna rod. Therefore, it becomes possible to maintain a sufficient locking effect for a long period without requiring a sever size accuracy. In addition, the entire surface of the tip portion of the joint section can be shaped to have sufficient large roundness. Therefore, a pointed component is not exposed outside, where the human body can be contacted, even in the state of detaching the antenna rod. In this embodiment, preferable manners are as follows. (1) ) A tip surface of the tip portion has a curved surface. In the state of detaching the antenna rod, the projection object mounted on the car does not give the person harm. (2) at least a part of the tip portion and the antenna rod has an elasticity body. The locking effect can be easily achieved without requiring a complex structural body.

Claims: A rod antenna device comprising: an antenna rod (23); and an antenna base (21) comprising a joint section (22) to which said antenna rod is connected, wherein said joint section comprises a tip portion (22a), said tip portion is covered with said antenna rod in a state of connecting said antenna rod, and a recess or salient engaging with an inner circumferential surface of said antenna rod is formed on an outer circumferential surface of said tip portion, characterised in that the rod antenna device is an on-vehicle rod antenna device further comprising a screw section (22C) which screws and connects said antenna rod with said joint section, and the recess or salient is substantially hemispherical. The on-vehicle rod antenna device according to claim 1, wherein a tip surface of said tip portion has a curved surface. The on-vehicle rod antenna device according to claim 1 or claim 2, wherein at least a part of said tip portion and said antenna rod has an elastic body.

Inventors: KAWAHATA JUNICHI, WANG JINSONG, KAWAHATA, JUNICHI, WANG, JINSONG
Applicants: HARADA IND CO LTD, HARADA INDUSTRY CO., LTD.
Application year: 2001
Main classification: H01Q1
IPC codes: H01Q1, H01Q9