Abstract:
Disclosed is a power antenna apparatus for automatically extracting/retracting an antenna. A motor is controlled by a control circuit to generate a rotational force. An antenna housing has a guide slot extending longitudinally on an inner surface thereof. A rotary member is installed in the antenna housing and is rotated by the motor. A coil spring is rotatably accommodated in the antenna housing and one end thereof is fixed to the rotary member. An antenna conveying member is received together with the antenna within the coil spring as being fixedly coupled with the antenna by a lower end of the antenna. The antenna conveying member has protrusions which are loosely inserted into the guide slot of the antenna housing and conveys the antenna along with the guide slot to extract or retract the antenna by means of a rotation of the coil spring. Other embodiments are disclosed for flexible installation of the apparatus. Application of the apparatus to a wireless telephone is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a power antenna apparatus, and more particularly, relates to a power antenna apparatus which, in a mobile communication apparatus such as a cellular phone and the like, enables an antenna to be automatically drawn out or led in. 
     2. Description of the Prior Art 
     Generally, a power antenna apparatus pulls an antenna into an antenna housing when not in use, draws out the antenna from the antenna housing by a rotational force of an electric motor when in use, and leads to pull the antenna again into the antenna housing when the use of the antenna is completed. 
     Recent researches into and developments on the technology of power antennas have been applied to antennas for mobile communication apparatuses such as mobile telephones, cellular phones and a personal communication system. 
     There has been a technology in which the drawing-out or the lead-in of an antenna is controlled by installing a rod at a lower end portion of the antenna and by transporting a screw rod with a turning force of an electric motor. Here, because the screw rod needs to be transported, a length of an antenna housing is required to be twice as long as a drawing-out length of the antenna. Also, because an external force which has an influence on the antenna is delivered to a transport mechanism as it stands, the external force acts on the transport mechanism or on the electric motor and thereby they are apt to be damaged or broken down. 
     In U.S. Pat. No. 5,497,506, disclosed is a technology in which the drawing-out or the lead-in of an antenna is activated by installing a transport nut at a lower end portion of the antenna and by transporting the transport nut under the guidance of a spiral of a screw rod with a turning force of the screw rod which is rotated by an electric motor. In this patent, because the screw rod is received into an inner side of a pipe-shaped antenna, a length of an antenna housing is required to be the same as a drawing-out length of the antenna. Similarly, because an external force which has an influence on the antenna is delivered to a transport mechanism as it stands, the external force acts on the transport mechanism or on the electric motor and thereby they are apt to be damaged or broken down. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide a power antenna apparatus in which, while an antenna transport assembly transports under guidance of a spiral of a rotating coil spring, a drawing-out or a lead-in of an antenna is controlled, an external force acted on the antenna is absorbed at the same time, and thereby the durability of a driving apparatus can be improved. 
     It is another object of the present invention to provide a power antenna apparatus in which an external force is absorbed by a coil spring and thereby a motor control circuit is configured by a simplified on/off control. 
     It is a further object of the present invention to provide a wireless communication apparatus which adopts the power antenna. 
     It is a fourth object of the present invention of the present invention to provide a power antenna apparatus which a motor as a power source for driving the antenna can allow to installed in a random place so that its application field can be extended to a mobile telephone with a narrow permissible space for installation. 
     According to the present invention, there is provided a power antenna apparatus for extracting/retracting an antenna from/into an antenna housing, comprising; a driving means for generating a rotational force; and a transporting means, accommodated in the antenna housing, for carrying the antenna in a longitudinal direction of the antenna as being conveyed along a spiral of a coil spring which is rotated by the driving means. 
     As another preferable aspect of the present invention, there is provided a power antenna apparatus for automatically extracting/retracting an antenna of a wireless communication device, comprising; a motor for generating a rotational force by using an electric energy; a motor control means for controlling operation of the motor by providing a driving power in response to a communication-start signal and a communication-end signal of the wireless communication device; an antenna housing having a guide slot extending longitudinally on an inner surface of the antenna housing; a rotary member installed at one end of the antenna housing and rotated by the motor; a coil spring rotatably accommodated in the antenna housing, one end of the coil spring being fixed to the rotary member; and an antenna conveying member received together with the antenna within the coil spring as being fixedly coupled with the antenna by a lower end of the antenna, having protrusions which are loosely inserted into the guide slot of the antenna housing, for conveying the antenna along with the guide slot to extract or retract the antenna by means of rotation of the coil spring. 
     As a further preferable aspect of the present invention, there is provided a power antenna apparatus for automatically extracting/retracting an antenna in a longitudinal direction of the antenna, comprising; a motor, having a driving shaft, for generating a rotational force by using an electric energy; a deceleration gear assembly engaged with the driving shaft of the motor; an antenna housing having a guide slot extending longitudinally on an inner surface of the antenna housing; a rotary member rotatably accommodated in the antenna housing and rotated by a transferred rotational force originated from the motor; a force transferring means, both ends thereof being fixed to the deceleration gear assembly and the rotary member, for transferring the rotational force of the motor to the rotary member; a coil spring rotatably accommodated in the antenna housing, one end of the coil spring being fixed to the rotary member, rotated together with the rotary member; and an antenna carrying member received together with the antenna in the coil spring as being fixedly coupled with the antenna by a lower end of the antenna, having protrusions which are loosely with the guide slot of the antenna housing, for carrying the antenna along with the guide slot to extract or retract the antenna by means of rotation of the coil spring. 
     As an preferable aspect of an application of the power antenna apparatus to a wireless communication apparatus, for example, a cellular phone and the like, there is provided a wireless communication apparatus having an antenna which is moved in a length direction thereof so as to be extracted from or retracted into a case of the wireless communication apparatus, the wireless communication apparatus comprising; a means for inputting/outputting an information; a transmitting/receiving circuit means for processing an input/output signal from the inputting/outputting means, for modulating the processed input/output signal into a radio signal and then transmitting the modulated radio signal through the antenna, or for demodulating a signal received through the antenna, processing the demodulated signal and providing the processed signal to the inputting/outputting means; a driving means for generating a rotational force in response to an operation of the transmitting/receiving circuit means; and a means for carrying the antenna, tightly coupled with the antenna, the carrying means moving in a longitudinal direction of the antenna along a spiral of a coil spring when the coil spring is rotated by the rotational force of the driving means, thereby carrying the antenna in the longitudinal direction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and other advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings, in which: 
     FIG. 1 is a perspective view for showing a structure of a power antenna apparatus according to an embodiment of the present invention; 
     FIGS. 2A to  2 C are views for showing structures of a plane, front and side of a rotation driving unit, respectively; 
     FIG. 3 is a disassembly perspective view for showing a structure of the power antenna apparatus shown in FIG. 1; 
     FIG. 4 is a view for showing a portion of a mobile telephone which adopts the power antenna apparatus according to the present invention; 
     FIG. 5 is a view for showing a structure of a wireless communication apparatus according to an embodiment of the present invention; 
     FIG. 6 is a flow chart for illustrating a control operation of a motor control section according to an embodiment of the present invention; 
     FIG. 7 is a view for showing a lead-in state of the power antenna apparatus shown in FIG. 1; 
     FIG. 8 is a view for showing a drawing-out state of the power antenna apparatus shown in FIG. 1; 
     FIG. 9 is a perspective view for showing a structure of a power antenna apparatus according to another embodiment of the present invention; 
     FIG. 10 is a view for showing a structure of a power antenna apparatus according to a further embodiment of the present invention; 
     FIG. 11 is a perspective view for showing a structure of the power antenna apparatus according to the present invention; 
     FIG. 12 is a disassembly perspective view of a power antenna apparatus according to a fourth embodiment of the present invention; 
     FIGS. 13A and 13B are a front view and a side view of a motor unit of the power antenna apparatus shown in FIG. 11; and 
     FIG. 14 is a sectional view of a wire assembly cut along line A—A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, a preferred embodiment of the present invention will be explained in detail with reference to the accompanying drawings. 
     FIG. 1 is a perspective view showing a preferred embodiment of a power antenna apparatus according to the present invention. As shown in FIG. 1; the power antenna apparatus comprises an antenna  10 , a driving unit  20  and a transport unit  30 . 
     FIG. 2 a  is a plan view showing the driving unit, FIG. 2 b  is a front view thereof and FIG. 2 c  is a side view seen from the left thereof. As shown in FIG. 2, driving unit  20  comprises a housing  22 , a motor  24 , a driving gear  26  and a following gear  28 . 
     Housing  22  comprises a motor supporting member  22   a  which has a cylindrical shape and of which one side is opened, and a couple of L-shaped supports which consist of extension portions extending parallel with a driving shaft  24   a  of motor  24  from both edges of motor supporting member  22   a  facing with each other and crank-shaped bent portions  22   c  bent from edges of extension portions  22   b . At both edges of bent portions  22   c  facing with each other, shaft holes  22   d  are formed so as to insert bosses  28   a  and  28   b  of following gear  28  therethrough. Driving gear  26  is a worm coupled to driving shaft  24   a  of motor  24 , and following gear  28  is a worm wheel positioned between a pair of bent portions  22   c , a shaft of following gear  28  being inserted into a pair of shaft holes  22   d . Worm and worm wheel  26  and  28  are engaged with each other. Shaft holes  22   d  have an inner diameter so that antenna  10  can pass therethrough. Lower boss  28   b  of worm wheel  28  is longer than an upper boss  28   a . The motor is a coreless type direct current (DC) motor whose diameter is, for example, about 4-6 mm. 
     Transport unit  30  comprises an antenna housing  31 , for example, being cylinder-shaped, a coil spring  32 , an upper supporting member  33 , a lower supporting member  34 , a carrying member  35  and a housing stopple  36 . 
     Antenna housing  31  is formed at an inner wall thereof with guide slots  31   a  extending longitudinally thereof and receives coil spring  32 . Coil spring  32  is rotatably supported by upper and lower supporting members  33  and  34 . Upper supporting member  33  is rotatably assembled at a latching groove  33   a  thereof to a shoulder  31   b  formed around an upper entrance of antenna housing  31 . An upper edge of coil spring  32  is press-fitted to an outer wall of boss  33   b . Preferably, an inner wall of upper supporting member  33  and an outer wall of lower boss  28   b  of following gear  28  are tightly coupled so as to ensure a stable transmission of the rotational force originated from motor  24 . Housing stopple  36  is press-fitted into a lower entrance of antenna housing  31 . 
     Carrying member  35 , having a cylinder shape, is placed inside of coil spring  32  and is formed with a couple of protrusions  35   a  which are protruded through coil spring  32  and are inserted to guide slots  31   a  formed at the inner wall of antenna housing  31 . Preferably, protrusions  35   a  have a rod shape. Antenna  10  is inserted at a lower edge thereof to a hole  35   b  of carrying member  35 . 
     Preferably, transport unit  30  is made of a resilient material so that it can be installed even in a space which is not straight. Even if antenna housing  31  and coil spring  32  are bent slightly, the bent structure cannot affect to a vertical movement of carrying member  35  since a pitch of the coil is much shorter than a whole length of coil spring  32 . 
     Hereinafter, the assembling process of the power antenna apparatus according to the present invention will be described with reference to the accompanying drawings. FIG. 3 is an exploded perspective view showing an embodiment according to the present invention. 
     At first, carrying member  35  is installed inside coil spring  32 . Upper supporting member  33  is press-fitted into an upper edge of coil spring  32  and lower supporting member  34  is assembled to a lower edge of coil spring  32 . Housing stopple  36  is press-fitted into the lower entrance of antenna housing  31 . Then, the coil spring assembly is inserted to the upper entrance of antenna housing  31 . Upper supporting member  33  is press-fitted at latching groove  33   a  thereof to shoulder  31   b  formed on an upper inner wall of antenna housing  31 , thereby completing the assembling of the transport unit  30 . 
     Upper supporting member  33  of assembled transport unit  30  is press-fitted into lower boss  28   b  of following gear  28  of driving unit  20 , thereby assembling transport unit  30  to driving unit  20 . 
     Antenna  10  is inserted through a shaft hole  28   c  of following gear  28  and is further inserted into the hole formed at carrying member  35  of transport unit  30 , thereby completing the assembling thereof. 
     FIG. 4 is a cross-sectional view showing the power antenna apparatus of a wireless communication apparatus such as a cellular phone and the like. Driving unit  20  is installed inside a case  50  of the cellular phone. Lower boss  28   b  of following gear  28  is protruded outside the case by a predetermined distance through an opening  50   a  formed at case  50  so as to be assembled to transport unit  30 . Transport unit  30  is installed at a rear portion of the case at which a battery pack (not shown) is assembled. Accordingly, transport unit  30  is installed between the battery pack and a rear wall of case  50  so that transport unit  30  is not exposed to an outside thereof after the battery pack is assembled. As mentioned above, for coupling driving unit  20  with transport unit  30 , driving unit  20  is assembled at lower boss  28   b  of following gear  28  thereof to the hole formed at upper supporting member  33 . In the state that driving unit  20  and transport unit  30  are assembled with case  50 , antenna  10  is inserted through a bore (not shown) formed at a center of a coil antenna  51 , then being further inserted through shaft hole  28   c  of following gear  28 , being finally inserted into the hole formed at carrying member  35  previously inserted into antenna housing  31 . Coil antenna  51  is screwed to an antenna connection section (not shown) of a transmitter-receiver circuit. 
     Therefore, driving unit  20  is assembled into the case at the same time when inside elements of the cellular phone are assembled into the case. Transport unit  30  and antenna  10  are easily assembled from the outside thereof after the casing process is finished. The above described structure can compatibly be installed in an installing space of a conventional cellular phone. When antenna  10  is fully extracted, a metal part  10   a  of a lower portion of antenna  10  makes contact with a metal part  51   a  of a lower portion of coil antenna  51  so as to electrically communicate with the transmitter-receiver circuit. 
     FIG. 5 shows a circuit of the wireless communication apparatus shown in FIG.  4 . As shown in FIG. 5, the cellular phone comprises an input-output section  52 , transmitter/receiver circuits  54 , a power supplier  56  and a motor control section  40 . 
     Input-output section  52  comprises a microphone  52   a , a speaker  52   b , a keypad  52   c  and a liquid crystal display section  52   d . Transmitter/receiver circuits  54  comprise a signal processing section  54   a , a transmitting section  54   b  and a receiving section  54   c . Input-output section  52  inputs a sound information through microphone  52   a  and outputs the sound information through speaker  52   b . And, input-output section  52  inputs a function command and a telephone number by keypad  52   c  and displays the function, number and characters on liquid crystal display section  52   d  with regards to the input. 
     In transmitter/receiver circuits  54 , the input and output signals from input-output section  52  are signal-processed at signal processing section  54   a  and are modulated to a high frequency signal by transmitting section  54   b  so as to transmit the modulated signal through antenna  10 . A signal received through antenna  10  is demodulated by receiving section  54   c , is processed by signal processing section  54   a  and is then given to input-output section  52 . Also, signal processing section  54   a  of transmitter/receiver circuits  54  generates a communication-start signal and a communication-end signal. 
     Power section  56  receives an energy from a battery  58  so as to generate operating voltages(B+) for each circuit section. 
     Motor control section  40  comprises a power section  42  and a control section  44  consisting of microprocessors. The operating voltage(B+) supplied from power section  42  is adjusted to a driving voltage(Vcc) through a power circuit  42  so as to be transmitted to control section  44 . Also, from transmitter/receiver circuits  54 , the communication-start and communication-end signals are transmitted to control section  44 . Control section  44  comprises a one-chip microprocessor and receives the communication-start and communication-end signals so as to drive motor  24  clockwise or counterclockwise during a predetermined time. 
     Hereinafter, the operation of the present invention will be described with reference to the accompanying drawings, especially FIG.  6 . 
     At an initial state, antenna  10  is retracted in antenna housing  31  as shown in FIG.  7 . At this state, when the user opens a flip-type cover and pushes a button, the communication-start signal is transmitted to control section  44  through transmitter/receiver circuits  54  and is checked by control section  44  (step ST 100 ). That is, when the input of the communication-start signal is detected, control section  44  drives motor  24  to be rotated in a positive direction, that is, a forward direction (step ST 102 ). 
     While motor  24  is rotating in the positive direction, a rotational force is transmitted to coil spring  32  through driving gear  26 , following gear  28  and upper supporting member  33  in turn so that coil spring  32  rotates counterclockwise when being viewed from a lower entrance of antenna housing  31 . At this time, a spiral slant of the coil spring  32  thrusts protrusions  35   a  of carrying member  35  into a spiral direction of the coil spring  32 . Since protrusions  35   a  are confined within guide slots  31   a  and thus a tangential component with respect to the rotational axis of a spiral directional force can not contribute to an effective movement of carrying member  35  into a circumferential direction and only a vertical component of the spiral directional force is effective for a movement of carrying member  35 , protrusions  35   a  are forced to move upward along guide slots  31   a . Accordingly, as carrying member  35  moves upward along guide slots  31   a , antenna  10 , whose lower end is tightly coupled with carrying member  35 , moves upward so as to be extracted from antenna housing  31 . 
     Control section  44  compares an operation time of motor  24  in the positive direction with a predetermined time (step ST 104 ). For this comparison, control section  44  accumulates the operation time during the operation of motor  24 . When the operation time is below the predetermined time, control section  44  keeps on the accumulation of the the operation time (step ST 106 ), and implements again step ST 104 . When the accumulated operation reaches the predetermined time, control section  44  stops the operation of motor  24  (step ST 112 ) and returns to step ST 100 . That is, the predetermined time is the time to be taken for antenna  10  to be fully extracted from antenna housing  31  as shown in FIG. 8 from a state of being fully embedded in antenna housing  31  as shown in FIG.  7 . The predetermined time can be obtained by a method of trial and error under a specified condition of the power antenna apparatus. Here, preferably motor  24  is controlled to rotate further so that coil spring  32  can be rotated further one or two turns over an expected moving distance so as to push up the metal part  10   a  of the lower end of antenna  10  to a contacting portion of a cellular phone circuitry. This improves a contacting reliability so as to avoid a sensitivity decrease and a noise generation, thereby improving the communication quality. 
     When the user closes the flip-type cover after the communication is finished or pushes an end button, transmitter/receiver circuits  54  generate the communication-end signal and control section  44  checks the generation of the communication-end signal (step ST 108 ). That is, when the communication-end signal is checked at step ST 108 , control section  44  drives motor  24  in a negative direction, that is, a backward direction (step ST 110 ). By the backward rotation of motor  24 , a rotational force is transmitted to coil spring  32  through driving gear  26 , following gear  28  and upper supporting member  33  in turn so as to rotate coil spring  32  clockwise. 
     At this time, the spiral slant of coil spring  32  urges protrusions  35   a  of carrying member  35  to a spiral direction. In this case, in the opposite of the case of the counterclockwise rotation of coil spring  32 , since protrusions  35   a  are confined by guide slots  31   a , only a vertical downward component of the spiral directional force is effective and protrusions  35   a  are forced to move downward along guide slots  31   a . Accordingly, carrying member  35  moves downward along guide slots  31   a  and thus antenna  10  of which the lower end is secured to carrying member  35  moves downward so as to retract into antenna housing  31 . Control section  44  also compares the operation time of the motor in the downward movement with the predetermined time (step ST 104 ). When the operation time is below the predetermined time, control section  44  keeps on the accumulation of the operation time (step ST 106 ) and carries out step ST 104  again. When the accumulated operation time becomes equal to the predetermined time, control section  44  stops the operation of motor  24  (step ST 112 ) and returns to step ST 100 . Here, the predetermined time is a time to be taken for antenna  10  to be fully retracted into antenna housing  31  as shown in FIG. 7 from a state of being fully extracted from antenna housing  31  as shown in FIG.  8 . Logically, an identical time can be applied as the predetermined time in both of the extraction and retraction. Here, motor  24  is controlled to rotate further so that coil spring  32  is rotated further one or two turns over the expected moving distance so as to attach a head of antenna  10  to the cellular phone case. 
     Meanwhile, when an external force is applied to the antenna during the movement of the antenna, that is, when the antenna is interfered by an obstacle in an extracting path upon being extracted or the antenna is held back by a hand upon being retracted, the external force will be transferred to carrying member  35  so as to stop a movement of carrying member  35 . But even in this case, motor  24  will be continuously driven to rotate coil spring  32  with overcoming the external force until the predetermined time would pass, but carrying member  35  can not advance forward. Accordingly, in both cases of the extraction and the retraction, one portion of coil spring  32  to be passed with respect to a current position of carrying member  35  is turned sparse in a coil turn to experience a tension. And, the other portion of coil spring  32  that has been already passed by carrying member  35  is turned dense in the coil turn to experience a compression. At this state, when the external force is removed, carrying member  35  moves quickly until the tension or the compression is relaxed. As a result, there is no difference in an advanced distance during a time interval with or without being interfered by the external force. 
     FIG. 9 depicts a second embodiment according to the present invention. The same elements other than the elements explained below are given to the same numerals. As shown in FIG. 9, the second embodiment is different from the first embodiment on the grounds that there are provided spur gears as a means for transferring the rotational force of a motor  64  in a driving unit  60  and that motor  64  is aligned laterally. That is, a driving gear  66  is coupled to a driving shaft of motor  64  and a following gear  68  is assembled to an upper edge of an extension portion  62   a  of a housing  62 . Driving and following gears  66  and  68  are engaged with each other. 
     FIG. 10 depicts a third embodiment according to the present invention. The same elements other than the elements explained below are given to the same numerals. As shown in FIG. 10, a motor  70  is installed within a lower entrance of antenna housing  31  and lower supporting member  34   a  is coupled to the driving shaft of motor  70 . Coil spring  32  is press-fitted into a boss of lower supporting member  34  so that lower supporting member  34  can directly transfer the rotational force of motor  70  to coil spring  32 . In this embodiment, despite not being shown in FIG. 10 precisely, a motor module including a deceleration gear assembly installed within a motor housing can be recommended as motor  70  in order to obtain a large torque. 
     FIGS. 11 to  14  illustrate a fourth embodiment of the present invention. In FIG. 11, the power antenna apparatus includes an antenna  110 , a driving unit  120  and a transport unit  130 . Referring to FIG. 12, driving unit  120  comprises a motor  210 , a deceleration gear assembly  220  for reducing an output speed of motor  210 , and a driving force transmission means  290  being connected to an output terminal of deceleration gear assembly  220  by a portion thereof and also being connected to transport unit  130 . A coreless-type direct current motor whose size is as small as a diameter of 4 to 6 mm is also recommendable as motor  210 . Reduction gear assembly  220  includes a first gear  222 , with a first diameter, installed to a driving shaft  212  of motor  210 ; a second gear  224 , with a second diameter larger than the first diameter, geared with first gear  222 ; a third gear  226 , with a third diameter smaller than the second diameter, installed on a rotation shaft  225  extended from a center of second gear  224 ; and a fourth gear  228 , with a fourth diameter larger than the third diameter, geared with third gear  226 . A cylindrical element  229  with a blind hole  229   a  of a predetermined depth is extended from a canter of fourth gear  228 . 
     When driving shaft  212  and the rotation shaft of second gear  224  are aligned in parallel, first gear  222  and second gear  224  are geared in a spur gear way with each other. When driving shaft  212  and the rotation shaft of second gear  224  are aligned perpendicularly, first gear  222  and second gear  224  are geared in a worm-worm wheel gear way with each other. 
     Transport unit  130  includes a cylinder type antenna housing  131 , a coil spring  132 , a carrying member  135 , a housing stopple  133  and a rotation member  300 . Carrying member  135  is the same with carrying member  35  aforementioned . 
     Antenna housing  131  is formed on an inner wall with a pair of guide slots  131   a  extending laterally and receives coil spring  132 . Coil spring  132  is rotatably supported and confined within antenna housing  131  by housing stopple  133  and rotation member  300 . Housing stopple  133  is press-fitted into an upper top portion of antenna housing  131 . 
     Rotation member  300  is a cylinder type member and is formed on an outer surface with a circular groove  310 . Rotation member  300  has a cylindrical neck  320  which extends a predetermined length from a top surface thereof. Cylindrical neck  320  has a blind hole  330  of a predetermined diameter which extends thereinto from a base surface thereof. Antenna housing  131  is formed on a lower side of an inner surface thereof with a circular projection  131   b  so that, when being inserted into antenna housing  131 , rotation member  300  is engaged with circular groove  310  with a margin to be set rotatably. 
     Driving force transmission means  290  includes a flexible wire  230  that both ends thereof are press-fitted into blind hole  229   a  of cylindrical member  229  and blind hole  330  of rotation member  300 , respectively. Flexible wire  230  cam be made of, for example, a Fe-Ni alloy. Preferably, flexible wire  230  is recommended to have a tensile strength as strong as 100 kgf/mm 2 , a coefficient of thermal expansion as low as 5×10 −6 /, a rupture strength as strong as 16 times or more. Here, the rupture strength can be defined as a twist-time of the flexible wire being turned into a twisted state at which the flexible wire will begin to be broken down when the flexible is twisted in a speed of 60 rpm under a condition of a ratio of a diameter to a length being 100. As for another embodiment, flexible wire  230  can be made of a strong synthetic resin against the twist. Moreover, driving force transmission means  290  can further include a reinforcing member in order to minimize the twist phenomenon of flexible wire  230  by a rotation of motor  210 . The reinforcing member includes multiple solid members  240  being regularly arranged along with flexible wire  230  and being tightly extrapolated to flexible wire  230 . Effective reinforcement can be accomplished because the whole length of flexible wire  230  has little change and a length to be twisted in reality can be reduced owing to solid members  240 . According to an installation location of motor  210 , flexible wire  230  is arranged between motor  210  and rotation member  300  so as to minimize a degree of suspension curvature of flexible wire  230 . A wire assembly  290 , as a simple constitution of driving force transmission means  290 , is covered up by a covering cable  250 . Covering cable  250  is manufactured by a multiple steel wire fiber being twisted, having a cylindrical cavity, being flexible and strong against a mechanical compression or twist. Covering cable  250  is pasted on an inner surface being contacted with wire assembly  290  with a grease  255  so as to reduce a frictional force caused by a rotation of wire assembly  290 . The whole length of wire assembly  290  is received by covering cable  250  so that, while motor  210  is in operation, wire assembly  290  can be prevented from being vibrated and dropped and thus wire assembly  290  can be rotated smoothly. 
     Meanwhile, carrying member  135  is formed on an outer surface with a pair of protrusions  135   a  extending out coil spring  132  and being inserted into a pair of guide slots  131   a  of antenna housing  131 . When coil spring  132  is rotated, carrying member  135  is carried along a spiral of coil spring  132  into a lateral direction of antenna  110  to extract of retract antenna  110 . 
     With reference to FIG. 12, an assembly order of transport unit  130  will be described below. Firstly, coil spring  132 , having being received in an inner space thereof with carrying member  135 , is inserted through an upper entrance into antenna housing  131 , and then housing stopple  133  is press-fitted into the upper entrance of antenna housing  131 . Next, rotation member  300  is pushed into a lower entrance of antenna housing  131  so as to make circular groove  310  of rotation member  300  be fitted to circular protrusion  131   b  formed in the inner surface of antenna housing  131 . By doing this, a work of assembling transport unit  130  can be completed. 
     Both motor  210  and deceleration gear assembly  220  can be assembled into a single motor unit  201 . FIGS. 13A and 13B are a front view and a side view of motor unit  201 , respectively. Respective gears are rotatably supported by an inner wall of a motor unit case  203 . 
     Next, after a decision on where motor unit  201  is to be installed, wire assembly  290  with solid member  240 , coupled with solid member  240  and then covered by covering cable  250 , is press-fitted into blind hole  330  of rotation member  300  by one edge and to blind hole  229   a  of cylindrical member  229  protruded out from motor unit  201  by the other edge. 
     As shown in FIG. 14, wire assembly  290  is fully covered by covering cable  250  according to an installation location and a slant angle. When motor  210  is in operation, wire assembly  290  is rotated with experiencing a slight frictional force owing to grease layer  255  pasted on the contact between the inner surface of covering cable  250  and wire assembly  290 . Covering cable  250  receives a full length of wire assembly  290  therein, and thus a vibration and a drop of wire assembly  290  can be prevented. 
     If power antenna apparatus  100  of the fourth embodiment is applied to a wireless telephone as a cellular phone or the like, driving unit  120  is cased in an antenna housing of the wireless telephone together with other devices of the wireless telephone, and transport unit  130  and antenna  110  are simply assembled into the antenna housing after completion of the casing work. The structure as such makes possible the adaptive installation of power antenna apparatus  100  within a space of a conventional telephone As described above, an external force applied to the antenna is absorbed by the coil spring so as to prevent the external force from being transmitted to the driving device, thereby improving the reliability thereof and simplifying a control scheme of a driving motor into an ON/OFF control method making control circuit design work easy. 
     Also, the coil spring transmits the rotational force so as to simplify the construction thereof, thereby reducing the cost thereof and easily assembling the power antenna apparatus. 
     Moreover, an employed coil spring, as having a predetermined number of turns, control work to extract/retract the antenna can be performed by operating the driving motor to be rotated over predetermined times with little loss of energy. 
     Furthermore, the power antenna apparatus can be adapted to a conventional cellular phone by changing the conventional design slightly. 
     Furthermore, while the antenna is extracting, using a coil spring enables a compression to be applied in an extracting direction so as to make the metal part of the antenna contact with the cellular phone circuitry. Also, while the antenna is retracting, using the coil spring enables a compression to applied in a retracting direction so as to make the head of the antenna contact with the case. 
     Especially, according to the fourth embodiment, since the power antenna apparatus is structured so that the motor can transmit its driving force to the antenna with little dependency on the installation location of the motor, the motor is more free from the installation location, thereby extending an applicability of the power antenna apparatus. 
     Furthermore, according to the above-described structure of the power antenna apparatus, even when the antenna housing and the coil spring are bent slightly, the antenna transmission is not interfered therewith so that the power antenna apparatus can be installed even in a space which is not straight. 
     Furthermore, so far, the present invention is described with a structure in which the coil antenna and the antenna are separated from each other, but the present invention is more available at a structure in which both antennas are integrally formed. In the integrated antenna structure, the coil antenna is assembled to the head of the antenna when the antenna is extracted, so a vibration caused by the self-weight of the integrated antenna structure is not negligible. But the vibration can be absorbed in the coil spring according to the present invention. 
     While the present invention has been particularly shown and described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that various changes and modifications can be made within the scope of the invention as hereinafter claimed.