JPH0731608Y2 - Rod antenna - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a rod antenna that is configured to be extendable and retractable and is installed in an automobile or the like.

[Prior art]

As such a rod antenna, it is equipped with an antenna element in which a plurality of poles having different diameters are elastically fitted and connected to each other, and "bush made of elastic material" or "a strip wound in an annular shape" is provided between the poles in the connecting portion. It has been known in the past to reduce the pole sliding noise and waterproof by inserting a "resin-shaped film piece" (Shokai 51-128446,
See each bulletin No. Sho 61-70406).

[Problems to be Solved by the Invention] The problem here is that, in the case of the "bush made of an elastic material", there is expansion and contraction according to the temperature change due to the use environment, and in order to absorb this, there is a problem with the pole. It requires some clearance between them, making it difficult to achieve the intended purpose. Also, in the case of "a strip of resin film wound in an annular shape", it may have a waterproof effect by bending so that the middle part bulges when expanding each pole, but during expansion and contraction sliding of each pole. It is difficult to maintain the curved shape when shrinking or
The point is that clearance with the pole occurs and the intended purpose cannot be achieved sufficiently. In order to achieve the intended purpose even during expansion / contraction of each pole or during contraction, it is necessary to limit the material of the "resin film piece" to a soft material with extremely strong deformation creep. In this case, there are problems that dust and mud are likely to be caught inside the pole, the sliding friction resistance is increased, the surface of the pole is easily scratched, and the expansion / contraction driving force of the pole is increased. Therefore, the present invention is a rod antenna that can always expect a good waterproofing effect regardless of the temperature change due to the use environment and the expansion / contraction state of the pole, and can avoid the inclusion of dust or mud, the damage to the pole, the increase in driving force, etc. The purpose is to provide.

[Means for Solving the Problems]

For this purpose, the present invention comprises an antenna element in which a plurality of poles having different diameters are telescopically fitted and connected, and a sleeve fitted between the poles of the antenna element,
The sleeve is provided with a radial elastic force by cutting over the entire length to elastically contact the inner surface of the large diameter side pole, and the tip portion is tapered in diameter by a plurality of notches extending in the axial direction from the tip surface. It is made of a hard material that can elastically contact the outer surface of the small diameter side pole, and the tip of each large diameter side pole is tapered to reduce the diameter by engaging with the tip of the sleeve. By forming an inner taper portion that elastically contacts the outer surface of each small diameter side pole.

[Action]

In such a means, when the antenna element is stretched and an initial load is applied between the plurality of poles, the sleeve elastically contacting the inner surface of the large-diameter side pole has a plurality of notches at the tip of the large-diameter side pole. The diameter is reduced in a taper shape by engagement with the inner surface tapered portion, and is held in a state of elastically contacting the outer surface of the small diameter side pole. In this way, even if there is a clearance between the tip of the large-diameter side pole and the outer surface of the small-diameter side pole, a waterproof seal is provided between the two poles via the sleeve. Here, since the sleeve has an elastic force in the radial direction due to the slitting over the entire length, it can sufficiently absorb expansion and contraction according to temperature changes due to the use environment, and even after the initial load between the poles is removed, The tip is kept tapered to reduce the diameter and seal between the poles.
Therefore, a good waterproof effect can always be expected regardless of the temperature change due to the use environment and the expansion / contraction state of the pole. Further, since the sleeve is made of a hard material, dust and mud are not entrained, sliding resistance is reduced, and scratches on the pole and increase in driving force can be avoided.

【Example】

An embodiment of the present invention will be specifically described below with reference to the drawings. In the rod antenna shown in FIG. 1, reference numeral 1 is an antenna element, and a plurality of poles 2, 3 and 4 having different diameters are telescopically fitted and connected, and an antenna top 5 is fixed to a tip pole 2. Has been done. Further, reference numeral 6 is an antenna housing cylinder, and the antenna element 1 can be housed in a contracted state. Here, as shown in FIG. 2, a sleeve 7 is inserted between the poles 2, 3 and 4 of the antenna element 1. The sleeve 7 is made of a hard material, that is, metal such as phosphor bronze, brass, nickel silver, or hard plastic such as nylon, polyacetal, or Teflon. A plurality of cuts 7a extending along the axial direction are formed at the tip of the sleeve 7, and a slit 7b bent in a "dogleg" shape is formed at one position in the circumferential direction over the entire length. It is possible to reduce the diameter with elasticity in the radial direction (see Fig. 3). On the other hand, the tips of the poles 2, 3 and 4 are drawn, and the inner surfaces thereof are each formed with a taper of about 3 to 10% of the inner diameter to form, for example, an inner taper portion 4a. In FIG. 2, reference numerals 8 and 9 are a stopper ring and a sliding spring mounted on the base end of the small diameter side pole 3, respectively. The rod antenna having the above structure is assembled so that each sleeve 7 is elastically contacted with, for example, the inner surface of the pole 4 on the larger diameter side, as shown in FIG. Therefore, when the antenna element 1 is stretched and an initial load is applied between the plurality of poles 2, 3, and 4, for example, the sleeve 7 elastically contacting the inner surface of the large diameter side pole 4 has a base end portion of the small diameter side pole 3. It moves upward along the large diameter side pole 4 due to the engagement with the stopper ring 8 mounted on (see FIG. 4 (b)). The tip of the sleeve 7 is guided by the inner surface tapered portion 4a of the large-diameter side pole 4 so as to be tapered so that the notches 7a come into close contact with each other (see FIG. 5). It is held in a state of being elastically contacted with (see FIG. 4 (c)). In this way, even if there is a clearance between the tip of the large diameter side pole 4 and the outer surface of the small diameter side pole 3, the two poles 3 and 4 are reliably waterproof-sealed via the sleeve 7. Here, since the sleeve 7 has the elastic force in the radial direction due to the slit 7b over the entire length, it is possible to sufficiently absorb the expansion and contraction according to the temperature change due to the use environment such as high temperature and cold. Further, even after the initial load between the poles 2, 3 and 4 is removed, the plurality of notches 7a keep the tip portion tapered in diameter and seal between the poles 3 and 4. Therefore, a good waterproofing effect can always be expected irrespective of the temperature change due to the use environment and the expansion / contraction state of the pole. Further, since the sleeve 7 is made of a hard material, dust and mud are not caught when the antenna element 1 expands and contracts, and the sliding resistance is small. Therefore, it is possible to avoid damage to the poles 2, 3 and 4 and increase in driving force. Furthermore, the slit 7b formed in the sleeve 7 has a "dogleg shape".
Since it is a refracted shape, it has a labyrinth effect, which is advantageous in terms of waterproof effect. In addition, this slit 7b is a "dogleg"
However, the straight type or the electric type may be used. Here, due to the presence of the sleeve 7, the connecting portions of the respective poles 2, 3, 4 are free from rattling, and the collision at the time of extension can be alleviated. Therefore, the antenna element 1 reduces sliding noise and collision noise of the pole. The sleeve 7 in the above embodiment may be made of a conductive synthetic resin mixed with metal powder, or a conductive synthetic resin having a sandwich structure in which conductors are sandwiched. Since it is performed at the tip of the pole, it is advantageous in terms of antenna characteristics.

[Effect of device]

As described above, in the present invention, when the antenna element is extended and an initial load is applied between the plurality of poles, the sleeve elastically contacting the inner surface of the large-diameter side pole has a plurality of notches, and the tip portion has a large-diameter side. The diameter of the pole is reduced by being engaged with the tapered portion of the inner surface of the pole, and the pole is held in a state of being elastically contacted with the outer surface of the small diameter side pole. In this way, even if there is a clearance between the tip of the large-diameter side pole and the outer surface of the small-diameter side pole, a waterproof seal is provided between the two poles via the sleeve. Here, since the sleeve has an elastic force in the radial direction due to the slitting over the entire length, it can sufficiently absorb expansion and contraction according to temperature changes due to the use environment, and even after the initial load between the poles is removed, The tip is kept tapered to reduce the diameter and seal between the poles.
Therefore, a good waterproof effect can always be expected regardless of the temperature change due to the use environment and the expansion / contraction state of the pole. Further, since the sleeve is made of a hard material, dust and mud are not entrained, sliding resistance is reduced, and scratches on the pole and increase in driving force can be avoided.

[Brief description of drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention, FIG. 2 is a sectional view of a main part of the embodiment, FIG. 3 is a perspective view of a sleeve used in the embodiment in a free state, and FIG. (A), (b) and (c) are explanatory views of the operation of the main part, and FIG. 5 is a perspective view of the sleeve in a reduced diameter state. 1 ... antenna element, 2,3,4 ... pole, 4a ... inner taper part, 5 ... antenna top, 6 ... antenna storage cylinder, 7 ... sleeve, 7a ... notch, 7b ... cut , 8
…… Stopper ring, 9 …… Sliding spring.

Claims (3)

[Scope of utility model registration request] 1. An antenna element, comprising a plurality of poles having different diameters that are telescopically fitted and connected to each other, and a sleeve fitted between the poles of the antenna element. Provides elastic force in the radial direction to elastically contact the inner surface of the large-diameter side pole, and the plurality of notches extending in the axial direction from the distal end surface reduces the diameter of the distal end in a taper shape to elastically contact the outer surface of the small-diameter side pole. It is made of a hard material that can be contacted, and the tip of each large diameter side pole is tapered to reduce the outer surface of each small diameter side pole by engaging with the tip of the above sleeve. A rod antenna, characterized in that an inner taper portion is formed to elastically contact with the rod antenna. 2. The rod antenna according to claim 1, wherein the sleeve is made of conductive synthetic resin. 3. The rod antenna according to claim 1, wherein the slits along the entire length of the sleeve have a bent shape.