JPH0327603A - Automatic antenna system - Google Patents

Abstract

PURPOSE:To eliminate the need for the mechanism converting a rotary motion into a straight motion, to make the weight of the system light and to improve the energy conversion efficiency by using an ultrasonic wave linear motor so as to move directly a drive member in the axial direction of an antenna rod. CONSTITUTION:An alternate voltage is applied to one or both of piezoelectric elements 11, 12 of an ultrasonic wave linear motor 5 to excite a vibrator 9. A longitudinal vibration and a torsional vibration are synthesized to the tip of legs 6, 7 to generate an elliptic vibration moved in a specific direction. Thus, the drive cable 3 is moved to any of axial directions of an antenna rod 2 in the rotating direction of the elliptic vibration and the rod 2 linked with one end of the cable 3 is shrinked in the axial direction. In this case, the phase of the alternate voltage applied to the piezoelectric elements 11, 12 is varied to change the rotating direction of the elliptic vibration, then the moving direction of the cable 3 is controlled. Thus, the drive mechanism converting the rotary motion into the straight line motion is not required thereby making the weight light and eliminating energy loss.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic antenna device that extends and contracts an antenna rod of a car radio or the like by remote control.

[Prior Art] Conventionally, in this type of automatic antenna device, a flexible cable is pushed through the inside of a telescopic antenna rod that is extendable and retractable in the axial direction, and one end of this cable is While connected to the tip of the antenna rod, the other end is connected to a drive mechanism, and the drive mechanism, which is activated in conjunction with a radio switch in the vehicle interior, connects the cable in the axial direction of the antenna rod. A structure is known in which the antenna rod is expanded and contracted by moving the antenna rod.

In such an automatic antenna device, the drive mechanism reduces the rotation of the motor using a worm gear mechanism and transmits it to the pinion gear, as shown in Japanese Patent Laid-Open No. 62-206902, for example. A device is known in which the rotation is transmitted to a rack formed on the side surface of the cable and converted into linear motion, thereby moving the cable in the axial direction of the antenna member.

[Problems to be Solved by the Invention] By the way, in the above-mentioned conventional automatic antenna device, since a motor is used as an actuator, the motor generates noise while the antenna rod is expanding and contracting, and this noise can cause radio interference. This has the disadvantage of deteriorating the reception condition.

In addition, it is necessary to provide a drive mechanism that converts the rotational motion of the motor into linear motion, which increases the weight of the device.Furthermore, the drive mechanism uses a worm gear with poor transmission efficiency, which reduces energy conversion efficiency. It also had the disadvantage of being low.

In addition, when the motor is stopped, the extension and retraction movement of the antenna rod is restricted by the self-stop action of the single-arm gear of the drive mechanism, so even if the antenna rod needs to be extended or retracted manually due to damage to the motor, etc. Another drawback was that it was virtually impossible to operate.

This invention was made in view of the above-mentioned circumstances, and is an automatic antenna device that can be lightweight by omitting a drive mechanism, can be operated manually, does not cause noise interference to the radio, and has high energy conversion efficiency. The purpose is to provide

[Means for Solving 11B] In order to solve the above problem, the present invention moves the drive shaft using an ultrasonic linear motor described in Japanese Patent Application No. 1-55572 previously filed by the present applicant. This allows the antenna rod to expand and contract.

That is, in the present invention, a drive shaft, one end of which is connected to the tip of the antenna rod, is pushed into the interior of a telescopic antenna rod provided in a telescopic manner, and the drive shaft is moved in the axial direction by an actuator. In the automatic antenna device that extends and contracts the antenna rod by moving the actuator, a vibrating element is attached to a vibrating body made of an elastic body as the actuator, and the vibrating element vibrates the vibrating body. An ultrasonic wave that generates longitudinal vibration and bending vibration at the end of a vibrating body, generates a driving force by elliptical vibration that is a combination of these longitudinal vibrations and bending vibration, and uses this driving force to move the drive shaft in the axial direction. This is achieved by using a linear mode.

[Function] According to the above configuration, the drive member is moved toward the antenna by the linear driving force of the ultrasonic linear motor. Move it in the axial direction of the 2nd door. This eliminates the need for a mechanism for converting rotational motion into linear motion, which makes it possible to reduce the weight of the device, and eliminates energy loss through these mechanisms, improving energy conversion efficiency.

Further, since the driving member is directly moved by the ultrasonic linear motor, the movement of the driving member is restricted by the frictional force acting between the ultrasonic linear motor and the driving member. Therefore, by operating the antenna rod against the frictional force, its length can be manually adjusted to a desired length.

Furthermore, since the driving member is moved by the ultrasonic vibration of the ultrasonic linear motor, electromagnetic noise is not generated during the expansion and contraction operation of the antenna rod, and radio interference is avoided.

[Example 1] An example of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes a main body of the apparatus, and a telescopic antenna rod 2 is attached to the upper part of the main body 1 of the apparatus.

This antenna rod 2 is made up of a plurality of rod members whose diameters are gradually reduced, which are sequentially coaxially and slidably fitted together to form a single extensible rod.

Furthermore, a drive cable (drive member) 3 is disposed inside the antenna rod 2 . This drive cable 3 is
It is made of a material having appropriate flexibility and is formed into a band shape, one end of which is connected to the tip 2a of the antenna rod 2. The other end of the antenna rod 2 is stored in a cable storage chamber 4 formed in the lower part of the device main body 1, and is wound along the inner wall of the cable storage chamber 4.

The drive cable 3 is connected to the ultrasonic linear motor 5.
The antenna rod 2 is moved in the axial direction of the antenna rod 2 by being brought into contact with the antenna rod 2.

The ultrasonic linear motor 5 will be explained below with reference to FIG.

In FIG. 2, reference numerals 6 and 7 are leg parts parallel to each other, and 8 is a body part connecting the base ends of these leg parts 6 and 7. 9.

The materials and dimensions of these leg members 6, 7 and body part 8 are selected as appropriate, but in the illustrated example, an elastic body made of aluminum is used as the material, body part 8 has 5@II openings x 26 holes, and leg part 6
, 7 is said to be a 5ll yoke x 15ssL. Vibrating body 9
Other materials that can be used include metal materials such as duralumin, iron, brass, or stainless steel, inorganic materials such as alumina, glass, or silicon carbide, and organic materials such as polyimide resin or nylon.

The corner of the vibrating body 9 has a diameter of 45 mm with respect to the legs 6, 7 and the body 8.
The mounting surface is chamfered at an angle of 1
Piezoelectric elements (vibration elements) 11 and 12 are attached to 0 using adhesive or the like. This piezoelectric element 1112 uses a laminated piezoelectric actuator or a single plate of piezoelectric ceramics, and is configured to ultrasonically vibrate in a direction perpendicular to the mounting surface 10 by an alternating voltage applied from a power source (not shown). The dimensions of the piezoelectric elements l1 and 12 are also appropriately selected in the same manner as the legs 6 and 7, etc., but in the example, those of 5@MenguchiX9@IIL are used.

Three guide rollers 13 are disposed along the longitudinal direction of the body 8 at positions facing the tips of the legs 6 and 7, respectively. Each of these guide rollers 13 is connected to each leg 6.
, 7, and its both ends are rotatably supported by the device main body 1.

Further, a six part 14 is formed in the center of the upper part of the apparatus main body 1, and a biasing pin l5 having a conical tip is fitted into this hole part l4 so as to be slidable in the axial direction. A spring 17 is disposed between the flange 16 formed near the tip of the biasing bottle l5 and the device main body 1, and the panel 17
The biasing pin l5 is always biased toward the body 8, and its tip is curved so that it is engaged with a recess l8 formed in the center of the upper surface of the body 8, and thereby the vibrating body 9 each leg 6, 7 of is biased towards the drive cable 3;
A drive cable 3 is supported between the legs 6, 7 and each guide roller l3.

Next, the operation of the automatic antenna device configured as above will be explained.

When an alternating voltage in the ultrasonic frequency range is applied to one or both of the piezoelectric elements l1 and l2 of the ultrasonic linear motor 5 to vibrate the vibrating body 9, longitudinal vibrations are generated at the tips of the legs 6 and 7. and the bending vibration are combined to generate elliptical vibration (elliptic vibration) that rotates in a specific direction. As a result, the drive cable 3 moves in either one of the axial directions of the antenna rod 2 in accordance with the rotating direction of the elliptical vibration, and as the drive cable 3 moves, the antenna connected to one end of the drive cable 3 The rod 2 is expanded and contracted in the axial direction.

At this time, the rotation direction of the elliptical vibration can be changed by changing the selection state of each piezoelectric element 11, 12, the phase of the alternating voltage applied to each piezoelectric element 1l, 12, etc. It is possible to control three movement directions. Moreover, the piezoelectric element l of the ultrasonic linear motor 5
When the voltage is not applied to the antenna rods 1 and 12, the drive cable 3 is supported between the legs 6 and 7 and the guide roller l3, and the frictional force acting therebetween and the rod members constituting the antenna rod 2 are antenna rod 2 due to the frictional force between
The expansion and contraction of is prevented.

As explained above, according to the automatic antenna device of this embodiment, the antenna rod 2 can be expanded and contracted by controlling the ultrasonic linear motor 5.
The antenna rod 2 can be freely controlled remotely, such as by extending or contracting it.

Moreover, the drive cable 3 is driven by the ultrasonic linear motor 5.
can be directly linearly moved in the axial direction of the antenna rod 2, so the drive mechanism that converts rotational movement into linear movement remains unchanged. Therefore, the weight of the device can be significantly reduced, and there is no energy loss associated with the drive mechanism, improving energy conversion efficiency and reducing the burden on the vehicle battery.

In addition, since the drive cable 3 is supported by the frictional force between the legs 6 and 7 of the ultrasonic linear motor 5 and the drive cable 3, the force of the spring 17 that biases the ultrasonic linear motor 5 is By appropriately selecting , the antenna rod 2 can be manually extended and contracted against the above-mentioned frictional force.

Furthermore, since the drive cable 3 is moved by ultrasonic vibrations of the ultrasonic linear motor 5, no electromagnetic noise is generated, and as a result, noise interference to the radio when the antenna rod 2 is extended or retracted is eliminated.

In addition, in this embodiment, in particular, the guide roller l3 is connected to each leg portion 6,
Although three antennas are provided at each end of each leg 6, the automatic antenna device of the present invention is not limited to this.
The number can be selected as appropriate, such as one in seven or four or more. Further, as shown in FIG. 3, the guide roller 13
Alternatively, the drive cable 3 may be sandwiched between two ultrasonic linear motors 5.

In addition, in this embodiment, the vibrating body 9 has two legs 6 and 7.
Although the body portion 8 and the body portion 8 are formed into a substantially F-shape, the present invention is not limited to this.
Of course, it is also possible to perform deformation such as curving the.

Moreover, it goes without saying that the legs 6 and 7 do not have to be arranged parallel to each other.

Further, the dimensions, arrangement, shape, etc. of each part of the ultrasonic linear motor illustrated in this embodiment are merely examples, and these can be arbitrarily changed in design depending on the overall shape of the automatic antenna device.

[Effects] As explained above, according to the present invention, since the driving member can be directly moved in the axial direction of the antenna rod by the ultrasonic linear motor, there is no need for a mechanism to convert rotational motion into linear motion. As a result, the weight of the device can be significantly reduced, and energy loss associated with the interposition of a drive mechanism is eliminated, improving energy conversion efficiency and reducing the burden on the battery.

In addition, since the drive member is directly driven by the ultrasonic linear motor, the antenna rod can be manually extended or contracted to the desired length by operating the antenna rod against the frictional force that acts between them. can be done.

Furthermore, since the drive member is moved by ultrasonic vibrations of the ultrasonic linear motor, no electromagnetic noise is generated, and noise interference with the radio during the expansion and contraction operations of the antenna rod is eliminated.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a diagram showing the overall configuration of an ultrasonic linear motor, and FIG. 3 is a diagram showing a modification of the above embodiment. Moving object, 11, 12...Piezoelectric element (vibrating element).

Claims (1)

[Scope of Claims] A driving member having one end connected to the distal end of the antenna rod and the other end protruding from the proximal end of the antenna rod is disposed inside the extendable antenna rod. In an automatic antenna device that extends and contracts the antenna rod by moving a driving member in the axial direction of the antenna rod using an actuator, the actuator includes a vibrating body made of an elastic body, and a vibration that excites the vibrating body. An element is attached, and the vibrating element generates longitudinal vibration and bending vibration at the end of the vibrating body, and a driving force is generated by an elliptical vibration that is a combination of the longitudinal vibration and bending vibration, and this driving force causes the driving member to An automatic antenna device characterized by using an ultrasonic linear motor that moves the antenna in the axial direction.