JPH09148814A - Driving device of expansion tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent buckling from generating in a tube even if a pulley rotates in an unintended direction at the time of an assembling that the edge of a flexible tube is restrained on a groove part for winding pulley. SOLUTION: This device is provided with a pulley 9 having a groove part 9a for winding connecting the one end of a flexible tube 2 with the side of an expansion tube and restraining the restraining part of the other end and the rotation driving source. On the axial line of the pulley 9, a screw rod 21 which freely slides in only an axial direction is provided and a male screw part 21b screwing into the female screw part 7c on the side of the pulley 9 is provided. A brake spring 23 pressing this screw rod 21 in an axial direction is provided at the one end and the slip plate 25 which is abutted on the edge of the pulley 9 at the time of a reverse rotation is provided at the other end. Engagement parts 26 and 27 for rotation transmission engaging within the range of a relative rotation are provided between a freely rotatable gear 13 for rotation transmission in the pulley 9 and the outer peripheral part of the boss part 9d. The moving amount to the other side of the screw rod 21 is set larger than the moving amount to the one side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a telescopic tube used as an on-vehicle electric corner pole provided in, for example, a bumper of an automobile.

[0002]

2. Description of the Related Art For example, it has been a conventional practice to attach a telescopic tube called a corner pole to a bumper of an automobile so that a driver can easily see the end of the automobile when the vehicle is put in a garage, in parallel parking, or when moving sideways. It is being appreciated. Some of such corner poles are configured so that they can be housed in a bumper by being driven by an electric actuator except when necessary in order to avoid damage when not in use.

In such a stowable electric corner pole, a flexible tube is inserted into a telescopic tube, one end of the flexible tube is connected to a tubular body on the tip side constituting the telescopic tube, and the other end is rotationally driven. It is connected to a pulley that is driven to rotate by an electric motor that is a power source, and the tube is extended or wound by the rotation of this pulley to extend or shorten the expandable tube. For example, the structure shown in Japanese Utility Model Laid-Open No. 6-75893. It has been known.

[0004] Such a conventionally known electric type corner pole 1 will be described with reference to FIG. 3. In FIG. 1, reference numeral 1 denotes a telescopic tube which is constructed by fitting a plurality of tubular bodies.
Is a flexible tube whose one end is connected to one tubular body (not shown) that constitutes this telescopic tube 1, and the telescopic tube assembly 3 which is a sub-assembly is constructed by assembling these flexible tubes. The flexible tube 2 is a wire made of metal or synthetic resin, and has a spherical locking portion 2a fixed to the other end, which is a winding end for a pulley on the drive unit side, which will be described later. Reference numeral 4 in the drawing denotes a decorative ring that is attached to the bumper B of the automobile as a telescopic tube holding portion and holds the telescopic tube 2 for housing or projecting.

Reference numeral 5 denotes a drive unit for expanding and contracting the expandable tube 1, and a pulley for winding and unwinding the flexible tube 2 and a rotation transmission mechanism (not shown) thereof for the case 6, and this case 6 An electric motor 7 which is a rotary drive source attached to the motor, a controller (not shown) for controlling the rotation of the motor 7, and a cylinder which is tangentially extended from a part of the case 6 and serves as a housing portion for the expansion tube 1. It is configured by the shape portion 8 and the like.

The expandable tube assembly 3 and the drive unit 5 having such a structure are separately assembled as shown in FIG. 3, and the engaging portion 2a of the flexible tube 2 is finally assembled.
4 (a) and (b) as shown in FIGS. 4 (a) and 4 (b), by engaging with a locking groove 9b formed in a part of the tube winding groove 9a formed in the pulley 9 in the case 6, In this state, by rotating the motor 7 in the winding direction,
It is assembled by winding it in the groove 9a of the pulley 9 and storing the expandable tube 1 in the tubular portion 8.

[0007]

However, according to the expansion tube driving device having the above-described structure, when the expansion tube assembly 3 is assembled in the driving device unit 5, a part of the flexible tube 2 is buckled. There is a risk that it will occur, and it is desirable to take some measures. That is, such buckling is caused by engaging the engaging portion 2a at the tip of the flexible tube 2 with the engaging groove portion 9b in the groove portion 9a on the pulley 9 side at the time of the above-described assembly, Motor 7 in the state
4 is mistakenly driven to rotate in the extension direction of the expansion tube 1 as shown by the UP direction in FIG.
Here, 2b in FIG. 4A indicates a deformed portion of the buckled tube 2.

When such deformation due to buckling occurs, internal stress is generated in the flexible tube 2 when the flexible tube 2 is wound around the pulley 9, and on the other hand, when unrolled,
Internal stress occurs that returns to a deformed state. In order to prevent the above-mentioned buckling, it is necessary to increase the wire diameter of the flexible tube 2 and increase its rigidity. On the other hand, when it is significantly buckled during assembly, it needs to be replaced, which often causes waste.

As a result of various studies on the above-mentioned problems in assembling the expansion tube assembly 3 into the drive unit 5, the present inventor has found the following two points.

(1) Contradiction between buckling resistance and bending stress of the flexible tube 2 Even in the current corner poles, locking means are attached to the rising end and the falling end, but at the time of locking, especially the rising end is locked. At this time, since the tube 2 receives a compressive force from the motor 7 due to the torque increased by the reduction gear mechanism, if the tube 2 does not have an appropriate rigidity, the compressive force as shown in FIG. Will lose and buckle. Therefore, if the wire diameter of the tube 2 is increased, the buckling resistance is
Since the bending moment M is
Is expressed by M = E × I / R. Here, E is the Young's modulus of the material, R is the bending radius of the material, r is the radius of the flexible tube 2, I is the second moment of the flexible tube 2, and I = π × (r ₂ ⁴
And -r ₁ ⁴⁾ / ^4. From the above calculation formula, it is understood that the bending strength of the tube 2 increases with the fourth power of the radius. This is effective.

On the contrary, from the viewpoint of bending stress, the bending stress σ is calculated by σ = r / R × E. The property of this equation means that the bending stress increases in proportion to the radius of the tube 2.

(2) Possibility of buckling due to reverse bending of the flexible tube 2 At present, the direction in which the expansion tube assembly 3 including the expansion tube 1 and the flexible tube 2 is inserted into the drive unit 5 is. As shown in FIGS. 3 and 4A and 4B, while the pulley 9 is rotated by the motor 7, the engaging portion 2a at the tip of the flexible tube 2 forming the expansion tube assembly 3 is pulled by the pulley. 9
The tip of the tube 2 is pressed so as to be sandwiched in the locking groove portion 9b due to the sandwiching. As a result, when the tube locking portion 2a is sandwiched in the locking groove portion 9b, the tube 2 is wound by the pulley 9.

However, if the person who assembles is mistaken in the operation and pushes the tube 2 and then rotates the motor 7 in the wrong direction, that is, in the feeding direction of the telescopic tube 1 (UP direction in the figure), the tip of the tube 2 is rotated. There is a drawback that the portion buckles to generate the deformed portion 2b. Therefore, in order to prevent the buckling of the flexible tube 2 of the expansion tube assembly 3 during assembly, it is necessary to give due consideration to the above-mentioned problems. It is desired to take some measures that can solve the problem of increasing the size of the motor 7 and increasing the size of the entire device.

The present invention has been made in view of the above circumstances, and it is easy to assemble or replace a rear assembly type telescopic tube assembly using a telescopic tube as a corner pole and a flexible tube to a drive unit. In addition, it does not cause deformation due to buckling of the flexible tube due to reverse rotation of the motor as in the conventional case, and the position of the tube locking part and the groove on the pulley side can be easily aligned during this assembly. In addition, it is an object of the present invention to obtain a drive device for a telescopic tube that can be used to downsize the motor and the entire device.

[0015]

In order to meet such demands, a drive device for an expansion tube according to the present invention includes an expansion tube which is formed by elastically fitting a plurality of tubes, and A flexible tube whose one end is connected to one of the tubular bodies constituting the above, and a winding groove portion for locking the locking portion provided at the other end of the flexible tube and winding the flexible tube. It has a pulley and a rotary drive source for expanding and contracting the expansion tube by winding or unwinding the flexible tube on the pulley by driving the pulley through a reduction gear mechanism. A screw rod which is slidably supported only in the axial direction and has an external thread portion on the outer peripheral portion that is screwed into an internal thread portion formed on the inner peripheral portion of the shaft hole of the pulley, and a brake spring that urges this screw rod in the axial direction. And the pulley is the axis of the screw rod The slip plate that comes into contact with the end of the pulley when it moves in the direction and regulates its movement, and the reduction gear mechanism that is rotatably provided on the outer periphery of the boss of the pulley and receives the rotation transmission from the rotary drive source. A gear is provided, and an engaging portion for transmitting rotation is provided between the final gear and the pulley within a range of one relative rotation, and the amount of movement of the screw rod to the other is provided. The brake spring is set so as to be larger than the one-way movement amount.

According to the present invention, when the rotation in the first direction is transmitted from the rotary drive source to the final gear constituting the reduction gear mechanism and the engaging portion on the final gear side to the pulley. , The flexible tube is fed out, the screw rod moves in one direction and compresses the brake spring, and the reaction of the flexible rod causes the boss of the pulley to press against the slip plate, tightening the screw with the pulley. Stops the rotation of the pulley, and when the rotation driving source transmits the rotation in the second direction to the pulley, the flexible tube is wound and the screw rod moves in the other direction, It is configured so that the tightening action of the screw is not generated.

According to the present invention, at the time of assembling the expansion tube assembly and the drive unit, the engaging portion at the tip of the flexible tube is engaged with the engaging groove portion in the winding groove portion on the pulley side. Even if the rotary drive source is rotated in the reverse direction in this state, the pulley remains in the locked state, and the conventional deformation due to buckling in the vicinity of the tube locking portion does not occur. Further, according to the present invention as described above, the flexible tube is drawn out or wound up by the pulley driven by the electric motor to form a telescopic tube to which one end of the tube is connected. The expansion tube can be extended or shortened by the movement of.

Here, the expandable tube is obtained by combining a plurality of tubular bodies having different diameters in a fitted state, and letting out the smallest diameter tube through the flexible tube in the axial direction or retracting it. It is an expandable and contractible tubular body, and is used, for example, as an on-vehicle electric corner pole or antenna. The drive unit is an electric motor as a rotary drive source,
It is composed of a reduction gear mechanism, a pulley, and the like, and winds and pays out the flexible tube. The final gear that constitutes the reduction gear mechanism is a pulley that is rotatably fitted around the boss of the pulley. The engaging portion that engages the final gear and the pulley within one rotation refers to an engaging piece that faces both members in the same rotation path.

[0019]

1 and 2 show an embodiment of a drive device for an expansion tube according to the present invention. In these drawings, in this embodiment, the expansion tube 1 is used as a bumper of an automobile. A case will be described in which it is installed upright and is used as a vehicle-mounted electric corner pole. It should be noted that the same or corresponding parts as those described with reference to FIGS.

Reference numeral 11 in the figure denotes a motor shaft 7 of the electric motor 7.
A worm 12 is fixed by press-fitting to a, a large gear 12a serving as a worm wheel with which the worm 11 meshes, and a stepped gear forming a reduction gear mechanism for transmitting rotational power, and 13 a stepped gear 12 Small gear 12
Final gears that also form a reduction gear mechanism that meshes with b, and are arranged in an internal space formed by the case body 14, the lid body 15, and the bottom lid 16 that form the case 6.

A pulley 9 for winding and unwinding the flexible tube 2 is arranged in the case 6 described above, and a mechanical positioning means (not shown) for rotationally positioning the pulley 9 is provided. ), And further, printed circuit boards 17 and 18 for providing various electric circuit parts are arranged at appropriate positions, and a signal line 19 to an LED for illumination in an expansion tube assembly (see FIG. 3) (not shown) is externally provided. Has been pulled out. Further, reference numeral 20 in the drawing denotes an opening provided in a part of the case main body 14 which serves as an entrance / exit of the flexible tube 2.

Reference numeral 21 denotes a screw rod disposed on the axis of the pulley 9 between the case body 14 and the bottom cover 16 which form the case 6, and the upper end portion 21a of the screw rod 21.
Is formed in an I-cut shape and has a body hole 2 of the same shape
2 is engaged with and supported, so that it is movable only in the axial direction. Further, a brake spring 23 is interposed between the lower end portion of the screw rod 21 and the bottom cover 16, whereby the screw rod 21 is always given an upward biasing force. Further, in this screw rod 21, a male screw portion 21b is formed on the outer peripheral portion except the I-cut upper end portion 21a.

On the other hand, a female screw portion 9c screwed to the male screw portion 21b is formed on the inner peripheral portion of the shaft hole of the pulley 9. Therefore, when the pulley 9 rotates, the screw rod 21, which is movable only in the axial direction and whose rotation is restricted, moves up and down. Here, this screw rod 21
Corresponds to the rotating shaft of the pulley 9, and the pulley 9 is pivotally supported between the case body 14 and the bottom cover 16.

In the figure, 9d is a boss portion provided on the pulley 9 and having the female screw portion 9c on the inner peripheral portion thereof.
A gap is always provided at the lower end of the, and a slip plate 25 is provided at the upper end. As a result, when the pulley 9 rotates, the pulley 9 can move downward, and when the pulley 9 moves upward, the pulley 9 makes sliding contact while being restricted in movement by the slip plate 25. In addition,
The final gear 13 is rotatably supported on the outer periphery of the boss 9d.

Thus, the final gear 1 which is relatively rotatable
As shown in FIGS. 1 and 2, between 3 and the pulley 9, as an engaging portion for allowing both members to rotate within one rotation and for allowing both members to rotate integrally, Engagement piece 2
6, 27 are provided at one or several places in the circumferential direction. Therefore, the rotation of the motor 7 proceeds from the worm 11 through the gear 12 and the final gear 13 to the engaging pieces 27, 26.
Is transmitted to the pulley 9 and the flexible tube 2 is wound or unwound.

Here, the female screw portion 9c of the pulley 9 described above
The female screw portion 21b of the screw rod 21 constitutes a brake mechanism for locking the rotation of the pulley 9 at the ascending end and the descending end when the flexible tube 2, that is, the expandable tube 1 is expanded and contracted. That is, the pulley 9 is rotated by the rotation transmission from the motor 7, and the screw rod 21 is rotated by the screw action.
When the spring 23 descends against the biasing force, the pulley 9 rises due to its reaction, and the upper end of the boss 9d is pressed against the slip plate 25 and slidably contacts both screw parts 9d and 21b. The tightening action stops the rotation of the pulley 9. Further, when the pulley 9 is reversed and rotated to release the brake, the slip plate 2
The smooth sliding contact with 5 allows the brakes to be smoothly released by rotating with the frictional resistance at the time of the reversal start being reduced to the minimum. The brake spring 2 described above
3 has a function of promoting loosening of the screw portion at the time of this reversal. At this time, the screw rod 21
Goes up, and conversely, the pulley 9 goes down.

According to the above construction, when the motor 7 starts rotating, the worm 1 press-fitted into the motor shaft 7a.
1 also starts rotating at the same time. This power is sequentially transmitted to the gear 12 and further to the gear 13. When the gear 13 is transmitted to the gear 13, the gear 13 and the pulley 9 have a rotatable structure. Therefore, after the gear 13 rotates by a certain angle, the gear 13 is rotated.
The engaging piece 26 provided at the end collides with and engages with the engaging piece 27 on the pulley 9 side, and the gear 13 pushes and rotates the pulley 9 in the same direction as it is.

Then, since the female screw portion 9c on the pulley 9 side and the male screw portion 21b of the screw rod 21 are screwed together, the screw rod 21 moves downward in the figure and compresses the brake spring 23. In such a state, the reaction causes the boss portion 9d of the pulley 9 to move to the slip plate 2
5 is brought into pressure contact with and in sliding contact. As a result, the rotation of the pulley 9 is stopped by the tightening action of the screw portions.

The above operation is an operation when the expandable tube 1 pushes the tube 2 from the down side (winding side of the tube 2) to the up side (feeding side of the tube 2). As a result, when the rotation of the pulley 9 is stopped, the compressive force on the tube 2 is no longer applied, so that buckling of the tube 2 on the pulley 9 side in the vicinity of the locking portion 2a does not occur. This is because the rotation of the pulley 9 is appropriately braked and stopped at a predetermined stop position by the screwing of the threaded portion with a simple structure, and the state is maintained. This is because when the three-dimensional body 3 and the drive unit 5 are assembled, the acting force for buckling the tube 2 is constrained so as not to work.

Next, when the motor 7 is rotated in the opposite direction to the above, the worms 11,
The rotational power is transmitted in the order of the gear 12 and the gear 13, and the gear 13 rotates in the opposite direction to that described above. At this time,
After one rotation, the engagement piece 26 of the gear 13 collides with the engagement piece 27 on the pulley 9 side from the side opposite to that at the time of up operation. Then, due to this impact, the slip plate 23, the pulley 9, and the female screw portion 9 of the pulley 9
The friction between c and the male screw portion 21b of the screw rod 21 changes from static friction to dynamic friction, and smooth rotation starts. here,
Since the upper end portion 21a of the rod 21 has an I-cut shape and is fitted in the I-cut hole portion 22 of the case 6, the rod 21 thereafter does not rotate and only moves up and down. Continue the rotational movement.

Further, since the end surface P of the upper end 21a of the screw rod 21 and the lower surface Q of the I-cut hole 22 of the case body 14 have a sufficient distance, when the winding of the flexible tube 2 is completed. However, the screw parts 21b, 9 of both members
c cannot be tightened. Of course, this is not necessary because no buckling force is generated on the winding side.

Next, prevention of reverse winding of the tube 2 when the expansion tube assembly 3 is inserted into the case 6 will be described. That is, as shown in FIGS. 4A and 4B described above, the relative positions of the winding groove 9a of the flexible tube 2 and the tube insertion opening 20 on the case 6 side may be the same. For example, when the engaging portion 2a of the tube 2 is inserted, the engaging portion 2a bush B on the distal end side of the tube 2 automatically fits in the winding groove portion. Even if the user erroneously operates the motor 7 in this state and rotates the motor 7 in the up side, that is, in the tube feeding direction, the pulley 9 does not rotate because it is in the locked state. That is, the reverse winding state, which has been a problem in the past, does not occur. Of course, if the pulley 9 is rotated in the normal direction, the pulley 9 starts to rotate smoothly according to the principle described above, the engaging portion 9a is pulled in, and the tube 2 is wound up.

Therefore, in such a structure, the post-expansion type expansion / contraction tube assembly 3 including the expansion / contraction tube 1 as the corner pole and the flexible tube 2 can be easily attached to or replaced with the drive unit 5. In addition, the deformation of the flexible tube 2 due to the reverse rotation of the motor 7 unlike the conventional case does not occur, and at the time of this assembly, the engaging portion 2a on the tube 2 side and the engaging groove portion 9b on the pulley 9 side are formed. The alignment of can be done easily. Further, in such a configuration, since the tube 2 having a relatively small diameter can be used, the driving force of the motor 7 may be small, so that the motor 7 can be downsized and the entire drive unit 5 can be downsized. .

In other words, according to the above configuration, the pulley 7 is rotated in the first direction from the motor 7 via the final gear 13 which constitutes the reduction gear mechanism and the engaging portion 26 on the final gear 13 side. When transmitted, the flexible tube 2 can be fed out, the screw rod 21 moves downward to compress the brake spring 23, and the boss 9d of the pulley 9 presses against the slip plate 23 by its reaction. The rotation of the pulley 9 can be stopped by the screw tightening action with the pulley 9 caused by. Further, when the rotation in the second direction is transmitted from the motor 7 to the pulley 9,
While the flexible tube 2 is being wound, the screw rod 21 moves upward, and the screw tightening action with the pulley 9 does not occur.

Therefore, when the telescopic tube assembly 3 and the drive unit 5 are assembled, the locking portion 2a at the tip of the flexible tube 2 is fitted into the locking groove portion 9b in the winding groove portion 9a on the pulley 9 side. Even if the motor 7 is rotated in the reverse direction in the engaged state, the pulley 9 maintains the locked state, and buckling does not occur near the engaging portion 2a of the tube 2 as in the conventional case. Of course, when the flexible tube 2 is drawn out or wound up by the pulley 9 driven by the motor 7, the distal end side tube body forming the expandable tube 1 to which one end of this tube 2 is connected is expanded and contracted. The tube 1 can be extended or shortened.

Here, in the above-described embodiment, although the concrete illustration and description are omitted, in the expansion tube 1 used as a corner pole, its assembly 3, and its drive unit 5, the structure of each part is as follows. , For example, actual Kaihei 6-
It is free to appropriately adopt the structure and shape as shown in Japanese Patent No. 75893.

The present invention is not limited to the structures described in the above-mentioned embodiments, and it is needless to say that the shape, structure, etc. of each part may be appropriately modified or changed, and various modified examples may be considered. To be Further, in the above-described embodiment, the case where the drive device for the expansion tube according to the present invention is applied to the vehicle-mounted electric corner pole has been described, but the present invention is not limited to this. Of course, it can be applied to equipment and devices similar to the above. Further, an illumination portion that can be recognized even at night may be formed on the above-described expandable tube 1, and the tubular body forming this expandable tube 1 may be formed of a conductive material.

[0038]

EXAMPLE An expandable / contractible tube 1 can be obtained by combining a plurality of tubular bodies having different diameters in a fitted state, and letting out the smallest diameter tube through the flexible tube 2 in the axial direction and winding it. It is composed of a simple tubular body and is used for an on-vehicle electric corner pole. Further, the drive unit 5 includes an electric motor 7 as a rotary drive source and reduction gear mechanisms 11, 12, 1
3, the pulley 9 and the like, and winds and pays out the flexible tube 2.

Further, the final gear 13 constituting the reduction gear mechanism is rotatably fitted around the boss portion 9d of the pulley 9. Further, the engaging portions 26 and 27 for engaging the final gear 13 and the pulley 9 within one rotation are constituted by engaging pieces facing both members in the same rotation locus.

[0040]

As described above, according to the expansion tube driving device of the present invention, the flexible tube having one end connected to one of the tubular members constituting the expansion tube and the engaging member provided at the other end. A pulley with a winding groove that locks the stopper and winds the flexible tube, and drives this pulley via a reduction gear mechanism to wind the flexible tube around the pulley and then extend and contract it. Equipped with a rotary drive source for expanding and contracting the pipe, a male screw part that is slidably supported only in the axial direction on the pulley axis and that is screwed into a female screw part formed on the inner peripheral part of the pulley shaft hole is on the outer peripheral part. A screw rod, a brake spring that urges the screw rod in the axial direction, a slip plate that restricts the movement of the pulley that comes into contact with the pulley end when the pulley moves in the axial direction, and a boss portion of the pulley Rotatable around the outer periphery And a final gear constituting a reduction gear mechanism that receives the rotation transmission from the rotary drive source, and the rotation transmission is performed by engaging the final gear and the pulley within a range of relative one rotation. Since the engaging portion is provided and the movement amount of the screw rod to the other side is set to be larger than the movement amount to the one side where the brake spring is provided, it will be described below in spite of the simple configuration. It has an excellent effect.

According to the present invention, when the telescopic tube assembly and the drive unit are assembled, the engaging portion at the tip of the flexible tube is engaged with the engaging groove portion in the winding groove portion on the pulley side. Even if the rotary drive source is rotated in the reverse direction in this state, the pulley remains in the locked state, and the conventional deformation due to buckling in the vicinity of the locking portion of the tube does not occur.

Further, according to the present invention, since there is no fear of deformation due to buckling of the flexible tube, it is possible to reduce the wire diameter of this flexible tube, which allows the pulley side to be reduced. The winding diameter of the tube and the winding load are also reduced, and as a result, the motor can be downsized and the entire apparatus can be downsized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a drive device for an expansion tube according to the present invention and showing a main body portion of the drive device.

FIG. 2 is a perspective view showing a main configuration of FIG.

FIG. 3 is an exploded view illustrating a schematic configuration of a vehicle-mounted electric corner pole to which the expansion tube drive device according to the present invention is applied.

4A and 4B show pulleys for winding and unwinding a flexible tube in a drive device for a telescopic tube, wherein FIG. 4A is a development view and FIG. 4B is a schematic view.

[Explanation of symbols]

1 ... Telescopic tube, 2 ... Flexible tube, 2a ... Locking part, 3 ...
Expansion tube assembly, 5 ... Drive unit, 6 ... Case, 7
... Electric motor (rotational drive source), 7a ... Motor shaft, 8 ... Cylindrical part, 9 ... Pulley, 9a ... Winding groove part, 9b ... Locking groove part, 9c ... Female screw part, 9d ... Boss part, 11 ... Worm ,
12 ... stepped gear, 13 ... final gear (reduction gear mechanism),
14 ... Case body, 15 ... Lid, 16 ... Bottom lid, 20 ... Tube opening, 21 ... Screw rod, 21a ... Upper end, 21b ... Male thread, 22 ... Body hole, 23 ... Brake spring, 25 ... slip plates, 26, 27 ... engaging pieces (engaging portions).

Claims (2)

[Claims] 1. An expandable tube which is formed by elastically fitting a plurality of tube bodies, and a flexible tube whose one end is connected to one of the tube bodies forming the expandable tube. A pulley having a winding groove for locking the locking portion provided at the other end of the flexible tube and for winding the flexible tube;
In a drive device for an expansion tube provided with a rotary drive source for driving the pulley via a reduction gear mechanism, the device is supported slidably only in the axial direction on the axis line of the pulley and in the inner peripheral portion of the shaft hole of the pulley. A threaded rod having an external threaded portion on the outer peripheral portion that is screwed into the formed female threaded portion, a brake spring that biases this threaded rod in the axial direction, and a pulley end portion when the pulley moves in the axial direction of the threaded rod. The final gear is provided with a slip plate that abuts and regulates the movement thereof, and a final gear that is rotatably provided on the outer peripheral portion of the boss portion of the pulley and that constitutes a reduction gear mechanism that receives rotation transmission from the rotary drive source. An engaging portion for transmitting rotation by engaging within a range of relative one rotation between the wheel and the pulley, and the amount of movement of the screw rod to the other side is controlled by the brake. Drive of the telescopic tube, characterized in that set to be larger than the amount of motion to one in which a root. 2. The expansion tube drive device according to claim 1, wherein the rotary drive source rotates the pulley in the first direction through the final gear forming the reduction gear mechanism and the engaging portion on the final gear side. When transmitted, the flexible tube is fed out, the screw rod moves in one direction to compress the brake spring, and the reaction thereof causes the boss portion of the pulley to press-contact the slip plate. The rotation of the pulley is stopped by the tightening action of the screw, and when the rotation in the second direction is transmitted from the rotation drive source to the pulley, the flexible tube is wound and the screw rod Is configured to move in the other direction so that the tightening action of the screw with the pulley does not occur.