JPH06312384A - Self-propelling device - Google Patents

Abstract

PURPOSE:To provide a self-propelling device which is excellent in shock resistance, having a prolonged use life, by reducing the number of components so as to miniaturize the self-propelling device so that it can easily run even through a meandering pipe line. CONSTITUTION:A self-propelling device 1 is composed of an axially expandable piezoelectric element 5, a movable element 4 attached at one axially end of the piezoelectric element 5, for receiving a frictional force from a stationary member, and control means for controlling the drive power applied to the piezoelectric element 5, so as to move the movable element 4 with the use of the inertia force of the piezoelectric element 5 and the frictional force given to the element 4 which are obtained when the piezoelectric element 5 is axially expanded and contracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-propelled device that uses a piezoelectric element (including an electrostrictive element) to expand and contract to make it self-propelled.

[0002]

2. Description of the Related Art As a self-propelled device of this type, for example, one disclosed in Japanese Patent Laid-Open No. 4-176770 has been proposed. This is because one end of the piezoelectric element in the expansion / contraction axis direction is fixed to a moving body that is slidably frictionally engaged with the inner surface of the pipe, and the inertial body is fixed to the other end of the piezoelectric element in the expansion / contraction axis direction. It is configured.

When operating this self-propelled device, an inertial force resulting from the inertial action generated in the inertial body when the piezoelectric element is suddenly expanded or contracted is applied to the movable body.
The moving body is slid against the surface of the stationary portion to move the self-propelled device little by little.

[0004]

In such a conventional self-propelled device, a movable body is fixed to one end of the piezoelectric element in the expansion / contraction axis direction, and inertia is applied to the other end of the piezoelectric element in the expansion / contraction axis direction. Since the body is fixed, the number of components increases, the self-propelled device becomes large in size, and this is likely to cause a problem in designing equipment using the device. In addition, there is a problem that processing and assembling costs increase.

Further, when the self-propelled device receives a mechanical shock from the outside, the inertial force generated in the inertial body may be applied to the piezoelectric element as an excessive shock and damage the piezoelectric element. The present invention has been made by paying attention to the above circumstances, and an object thereof is to reduce the number of constituent parts, to reduce the cost of processing and assembling, and to make the self-propelled device as a whole small and tortuous. Another object of the present invention is to provide a self-propelled device that can easily travel on a moving road and is less likely to be damaged by a piezoelectric element when receiving a mechanical shock from the outside.

[0006]

SUMMARY OF THE INVENTION A self-propelled device according to the present invention comprises a piezoelectric element which is capable of expanding and contracting in the axial direction, a movable body which is attached to one end of the piezoelectric element in the axial direction and which receives a frictional force from a stationary member, Control of traveling operation of moving the moving body by utilizing the inertial force of the piezoelectric element and the frictional force received by the moving body when the piezoelectric element expands and contracts in the axial direction by controlling the drive voltage applied to the piezoelectric element Means and means are provided.

[0007]

When a drive voltage is applied to the piezoelectric element through the control means, the piezoelectric element expands and contracts, and the expanding and contracting operation of the piezoelectric element imparts an impact force to the moving body. To move.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and operation of a conceptual first embodiment of the present invention will be described with reference to FIGS. The self-propelled device 1 of the present embodiment is for guiding the traveling of the brush 3 inside the channel 2 of the endoscope.

The self-propelled device 1 has a movable body 4 which frictionally engages with the inner surface of a channel 2 as a stationary member and receives a frictional force from the inner surface, and one end of which extends and contracts in the axial direction attached to the movable body 4. A movable actuator 6 including a possible laminated piezoelectric element (PZT) 5 is provided.

The laminated piezoelectric element 5 has one end in the expansion / contraction axis direction fixed to the moving body 4. Further, electrodes are connected in parallel to each of the laminated piezoelectric materials of the laminated piezoelectric element 5. The lead wire for connecting the one electrode and the lead wire for connecting the other electrode are bundled together to form a lead wire bundle 7 from the rear end side of the laminated piezoelectric element 5 to the channel 2
Is led to the rear through the inside of. This lead wire bundle 7
Is connected to a drive power source (not shown), and the control means controls the applied voltage to the laminated piezoelectric element 5.

A brush 3 for cleaning the inner surface of the channel 2
Are provided at the tip of the moving body 4 arranged on the tip side of the moving actuator 6, and the moving actuator 6 reciprocates the self-propelled device 1 to cause the brush 3 to move.
Also reciprocates in the channel 2 to clean the inner surface of the channel 2.

Next, the operation of the moving actuator 6 in the self-propelled device 1 having the above structure will be described. First, FIG.
A case where the first drive voltage having the waveform shown in (A) is applied will be described. In this case, the moving actuator 6 is
It operates in the procedure of a, b, a in (A).

First, as shown in FIG. 3 (A) 1, the moving body 4 is stationary in a state of frictionally engaging with the inner peripheral surface of the channel 2. Then, in this state, when the drive voltage having the waveform shown in FIG. 2A is applied, the piezoelectric element 5 is slowly contracted in the region a of the waveform, and is rapidly extended in the region b.

That is, since the piezoelectric element 5 contracts slowly in the region a of the drive waveform, in this case, the moving body 4 maintains the state of being held by the frictional force on the inner peripheral surface of the channel 2.
Further, in the region b of the drive waveform, the piezoelectric element 5 rapidly expands, so that an impact force that presses the moving body 4 to the left in FIG. 3 is generated in the moving body 4 for the following reason. That is, an inertial force is generated due to the mass of the piezoelectric element 5 itself, and the moving body 4 moves a minute amount to the left in FIG. 4 due to the impact force from the piezoelectric element 5. In this case, the weight of the piezoelectric element 5 and the moving body 4
The center of gravity determined by both the mass M and the
As shown in (b) of (A), it moves a small amount to the left in the figure.
In the subsequent region a, the piezoelectric element 5 contracts slowly.
By repeating this, the position of the center of gravity is moved to the left in the figure by a small amount.

On the other hand, when the second drive voltage having the waveform shown in FIG. 2 (B) is applied, the operation is performed in the procedure of c, d, c in FIG. 3 (B). In the c region of this drive waveform, the piezoelectric element 5 expands slowly, and in the d region, it contracts sharply, and this expansion / contraction cycle is repeated. Then, in the c region of the drive waveform, the piezoelectric element 5
In the case of slowly extending, the moving body 4 maintains the stationary state by the frictional force acting on the contact surface with the inner surface of the channel 2 as shown in c of FIG. 3 (B).

Further, the piezoelectric element 5 contracts abruptly in the d region of the drive waveform. In this case, the abrupt contraction of the piezoelectric element 5 causes the moving body 4 to be pulled to the right in FIG. 3B. Since a force is generated, the moving body 4 moves to the piezoelectric element 5
As a fixed point, the center of gravity determined by the own weight of the piezoelectric element 5 and the mass M of the moving body 4 due to the impact force from
It moves to the right in the figure as shown in.

Therefore, the operation of the moving actuator 6 as a unit is such that when the first drive voltage having the waveform shown in FIG. 2A is applied to the piezoelectric element 5, the moving body 4 moves to the left in FIG. The self-propelled device 1 moves in the channel 2 in the distal direction (FIG. 1). When the second drive voltage having the waveform of FIG. 2B is applied to the piezoelectric element 5, the moving body 4 moves to the right in FIG. 3, and the self-propelled device 1 moves backward in the channel 2. Return to (Fig. 1).

Here, since the moving actuator 6 for driving the self-propelled device 1 is composed of only the moving body 4 and the piezoelectric element 5 and the inertia body used in the conventional moving actuator is omitted, it is omitted. Compared with the moving actuator, the number of constituent parts can be reduced, processing and assembly costs can be reduced, and the overall structure of the self-propelled device 1 can be downsized. Therefore, it can be easily incorporated into a device to which the piezoelectric element 5 is applied, and the piezoelectric element 5 is less likely to be damaged when an external mechanical shock is applied to the piezoelectric element 5.

Therefore, the axial size of the self-propelled device 1 can be shortened, the passage through the bent portion of the endoscope channel 2 becomes easy, and the cleaning efficiency by the brush 3 increases. As the waveform of the drive voltage applied to the piezoelectric element 5, a drive voltage having a waveform as shown in FIGS. 4 and 5 can be used. When the voltage having the drive waveform shown in FIG. 4A is applied to the piezoelectric element 4, the time differential value of the voltage is inverted discontinuously (the movement of the piezoelectric element 5 suddenly changes from the expansion direction to the contraction direction). At P, the moving body 4 slides to the left. The step movement amount at this time is usually about several μm or less. When the voltage having the drive waveform shown in FIG. 4B is applied to the piezoelectric element 5, the time differential value of the voltage is discontinuously inverted (the point where the movement of the piezoelectric element 5 suddenly changes from the contracting direction to the extending direction). At P, the moving body 4 slides to the right. It does not slip at other points in the drive waveform.

The waveform shown in FIG. 5 can be driven similarly to the case shown in FIG. 2, but the waveform shown in (a) moves to the left and the waveform shown in (b). Then move to the right.

Next, the configuration and operation of the second conceptual embodiment of the present invention will be described with reference to FIG. The second embodiment is an example in which the above-mentioned lead wire bundle 7 is omitted. The moving actuator 12 in this embodiment has an internal unit consisting of a battery 9, a drive circuit 10 and a connecting portion 11 in an airtight or liquid-tight state in a circular tube body 8 frictionally engaging with the inner peripheral surface of the channel 2. To form a moving body, and one end of the laminated piezoelectric element 5 is attached through the connecting portion 11 of the internal unit. This laminated piezoelectric element 5 is hermetically sealed in a circular tube 8 by a sealing material 13 made of a suitable elastic material such as epoxy resin that allows each piezoelectric material to expand and contract in the axial direction. Lead wires (not shown) connected in parallel are connected to the drive circuit 10 as a control means and the battery at the connection portion 11.
The operation of the control means may be controlled by a switch arranged in the self-propelled device 1, or may be remotely controlled by using ultrasonic waves or the like. Therefore, the lead wire bundle 7 in the first embodiment is unnecessary.

In this embodiment, the laminated piezoelectric element 5 is a circular tube 8
Although sealed inside, since this sealing material 13 has elasticity, this piezoelectric element 5 performs the same expansion / contraction operation as described in connection with the first embodiment, and the expansion / contraction operation of this piezoelectric element 5 is performed. The mobile actuator 12 travels in the same manner.

In the case of this embodiment, by omitting the inertial body as described above, the cost can be reduced and the size can be made smaller than that of the conventional moving actuator, and the moving actuator 12 as a whole has the circular tube 8. Since it is sealed inside, the shock resistance is further improved while maintaining the hermeticity.

FIG. 7 shows a self-propelled device 15 according to the third embodiment, in which a plurality of moving actuators 16 are connected in series. The moving body 17 and the piezoelectric element 18 of the moving actuator 16 are formed in the same manner as in the first embodiment, and are connected in series via lead wire bundles 19, respectively. However, each moving body 17 has a brush 3a on its peripheral portion, and frictionally engages with the inner surface of the channel 2 via the brush 3a.

In this embodiment, the three moving actuators 16 on the front end side and the two moving actuators 1 on the rear end side are included.
6 is connected in the opposite direction. A lead wire bundle 19 is extended rearward from the moving body 17 of the moving actuator 16 on the rearmost end side, and each piezoelectric element 18 is connected to a drive power source (not shown) via the lead wire bundle 19, and each piezoelectric element 5 is connected by a control means. The applied voltage to is controlled.
In this case, for example, when the drive voltage having the waveform shown in FIG. 2A is applied to the piezoelectric elements 18 of the three moving actuators 16 on the front end side, the piezoelectric elements of the two moving actuators 16 on the rear end side are, for example, The drive voltage having the waveform shown in FIG. 2B is applied so that each moving actuator 16 moves in the same direction in the channel 2.

A plurality of such moving actuators 16
In the self-propelled device 15 provided with, since each moving actuator 16 is miniaturized, even if the endoscope channel 2 or another pipe is meandering, it can travel inside thereof. is there. Moreover, since the number of the brushes 3a is increased, the cleaning efficiency is improved.

FIG. 8 shows a fourth embodiment. The self-propelled device 20 of this embodiment is for guiding the travel of the insertion portion 23 of the endoscope inside the conduit 2a. That is, the moving actuator 22 of the self-propelled device 20 is composed of a front end member 24 as a moving body and a hollow laminated piezoelectric element (PZT) 25 having one end connected to the front end member 24. The piezoelectric element 25 is formed with insertion holes 26 and 27 through which the insertion portion 23 of the direct-viewing endoscope can be inserted. The insertion hole 26 of the front end member 24 is formed to have a small diameter that allows the insertion portion 23 of the endoscope to be closely inserted, and the insertion hole 27 of the piezoelectric element 25 is formed to have a large diameter that allows the insertion portion 23 of the endoscope to be loosely inserted. ing. Further, the front end member 24 is provided with a set screw 28 for tightening and fixing the insertion portion 23 passed through the insertion hole 26. The insertion portion 23 of the endoscope has an insertion hole 27 for the hollow laminated piezoelectric element 27 as shown in FIG.
It is inserted through the insertion hole 26 of the front end member 24 through and is fixed to the front end member 24 with a set screw 28. The front end portion 23a of the insertion portion 23 for direct observation is exposed from the front end surface of the front end member 4 and faces forward.

A coil 30 for protecting the piezoelectric material is wound around the outer periphery of the hollow laminated piezoelectric element 25. A lead wire 31 for voltage application is connected to the electrode 25 a of the laminated piezoelectric element 25.
Reference numeral 1 is guided rearward in the conduit 2a along the insertion portion 23 of the endoscope. The lead wire 31 is fixed to the outer periphery of the insertion portion 23 by using a stopper 32. In this way, the lead wire 31 is connected to a drive power source (not shown), and the voltage applied to the laminated piezoelectric element 25 is controlled by the control means.

The outer diameter of the front end member 24 of the self-propelled device 20 is larger than that of the laminated piezoelectric element 25.
The front end member 24 contacts the inner surface of the conduit 2a and receives a frictional force, and the rear end side of the laminated piezoelectric element 25 does not contact the inner surface of the conduit 2a. In FIG. 8, the front end portion 2
4 is not in contact with the inner surface of the conduit 2a,
The front end member 24 may have any shape as long as it can receive a frictional force from the inner surface of the conduit 2a, and may have a gap in part as shown in FIG.
As shown in FIG.

The moving actuator 22 of the self-propelled device 20 in this embodiment operates in the same manner as the moving actuator 6 described with reference to FIGS. And
When the self-propelled device 20 moves in the conduit 2a, the insertion portion 23 of the endoscope fixed to the front end member 23 is also moved along the conduit 2a.

FIG. 9 shows a fifth embodiment of the present invention, which is an example in which the frictional force acting between the moving body 34 and the inner surface of the conduit 2a by magnetism is increased. In this embodiment, a laminated piezoelectric element 35 having a hollow structure is arranged on the front end side, and a movable body 34 is arranged on the rear end side. This moving body 34
As described above, the insertion portion 23 of the endoscope is inserted into the hollow laminated piezoelectric element 35, and the insertion portion 23 moves the moving body 3
It is fixed to 4 by, for example, a set screw (not shown).
Furthermore, the moving body 34 is formed of a magnetic body (it is not always necessary to form the moving body).

Inside the moving body 34, an electromagnetic coil 36 is concentrically arranged around the center of the axis, whereby the moving body 34 is constructed as an electromagnet. The lead wire 37 leading to the electromagnetic coil 36 and the lead wire 31 for voltage application leading to the electrode 35a of the multi-layer piezoelectric element 35 as described above are put together and a stopper 32 is used to insert the insertion portion 23.
It is stopped on the outer circumference of. The lead wire 31 for voltage application is guided rearward through a through hole 38 formed in the moving body 34.

In this embodiment, the moving body 34 is constructed as an electromagnet. When the traveling operation is performed as described above, the electromagnetic coil 36 is excited to move the moving body 34 to the conduit 2a.
The magnetic attraction to the inner surface of the is performed. Therefore, the frictional force of the moving body 34 with respect to the inner surface of the conduit 2a can be increased, and the operation can be stabilized.
Since the frictional force with respect to the wall surface of the conduit 2a can be increased, the mass of the moving body 34 can be reduced accordingly. Further, the traveling speed and the traveling force can be increased. Further, when the pipeline to be traveled is not horizontal, for example, a vertical pipeline or an inclined pipeline can be easily moved along the inner surface thereof. Others are the same as the above-mentioned embodiment.

In this embodiment, instead of forming the electromagnet, the member of the moving body may be formed of a permanent magnet. However, in the case of using an electromagnet, the electromagnet may be excited only in the step in which the moving body should be kept stationary so that the stationary force is increased.

FIG. 10 shows a sixth embodiment of the present invention. In this sixth embodiment, a balloon 39 is used instead of the electromagnet for increasing the frictional force in the fifth embodiment.
Is provided on the outer periphery of the moving body 34. Balloon 3
The inside of 9 is connected to a supply path 40 and a discharge path 41 formed inside the moving body 34, and a supply tube 42 is connected to the supply path 40 and a discharge tube 43 is connected to the discharge path 41. The supply tube 42 and the discharge tube 43 are stopped together with the lead wire 31 for voltage application on the outer periphery of the insertion portion 23 by a stopper 32.

By supplying the pressurized fluid to the balloon 39 through the supply tube 42, the balloon 39 is inflated and pressed against the inner surface of the running pipeline 2a. This can increase the frictional force on the inner surface of the conduit 2a. This embodiment can travel not only when the conduit 2a is made of a magnetic material, but also inside the conduit made of a non-magnetic material.

FIG. 11 shows a self-propelled device according to a seventh embodiment of the present invention. This self-propelled device is formed as a medical capsule 50 that can be moved to an arbitrary site such as the stomach or duodenum.

The medical capsule 50 has a capsule main body 52 as a moving body that engages with the inner surface of the body cavity 2b, and a fixed portion 54 protruding inward of the capsule main body 52. Moving actuator 56 composed of possible laminated piezoelectric elements 55a and 55b
a and 56b. These laminated piezoelectric elements 55a,
Lead wire bundles 51a, 51b connected to the electrodes of each piezoelectric material are extended from the rear end side of 55b, and these lead wire bundles 51a, 51b are guided rearward from the capsule body 52 as an insulating cord 51, and a driving power source (not shown). The control unit controls the applied voltage to the laminated piezoelectric element 5.

In this embodiment, the pH detecting section 53 is arranged at the tip of the capsule body 52, and the pH detecting section 53 is provided.
An amplifier 57 and a telemetry unit 58 electrically connected to
And a power source 59 are housed in the capsule body 52,
Information is exchanged with the outside through the telemetry unit 58.
The entire capsule body 52 is formed in a closed structure,
The location where the pH detector 53 is disposed and the location where the insulating cord 51 is led out are also sealed.

The medical capsule 50 has two moving accumulators 56a and 56a which operate in the same manner as the above-mentioned embodiment.
By including b, these moving accumulators 5
By driving 6a and 56b individually, it is possible to travel in any direction. For example, when the moving accumulators 56a and 56b are simultaneously driven so as to operate in the same direction and at the same speed, the medical capsule 50 moves straight, and when driven only in one direction or in the opposite direction, it rotates. Although two moving accumulators are provided in this embodiment,
You may provide 3 or 4 or more as needed.

[0041]

As is apparent from the above, according to the self-propelled device of the present invention, the number of constituent parts can be reduced, processing and assembly costs can be reduced, and the structure of the self-propelled device can be made compact. In addition, it is possible to easily travel on a winding road, and the piezoelectric element is less likely to be damaged when a mechanical shock is applied from the outside, and the service life can be extended.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a self-propelled device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of a drive voltage applied to a piezoelectric element.

FIG. 3 is an explanatory view showing a principle of traveling operation by a moving actuator.

FIG. 4 is another waveform diagram of the drive voltage applied to the piezoelectric element.

FIG. 5 is another waveform diagram of the drive voltage applied to the piezoelectric element.

FIG. 6 is a schematic diagram of a self-propelled device according to a second embodiment.

FIG. 7 is an explanatory diagram of a self-propelled device according to a third embodiment.

FIG. 8 is an explanatory view showing a cross section of a part of a self-propelled device according to a fourth embodiment.

FIG. 9 is a partial sectional view of a self-propelled device according to a fifth embodiment.

FIG. 10 is a partial sectional view of a self-propelled device according to a sixth embodiment.

FIG. 11 is an explanatory diagram of a self-propelled device according to a seventh embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Self-propelled device, 2 ... Channel, 3 ... Brush, 4 ... Moving body, 5 ... Piezoelectric element, 6 ... Moving accumulator, 7 ... Lead wire bundle.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Keiichi Arai 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Yutaka Tatsuno 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Kenji Yoshino 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Yasuhiro Ueda 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Sakae Takehata 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd.

Claims (1)

[Claims] 1. A piezoelectric element that is capable of expanding and contracting in the axial direction, a moving body that is attached to one end of the piezoelectric element in the axial direction and that receives a frictional force from a stationary member, and a drive voltage that is applied to the piezoelectric element is controlled to control the piezoelectric element. Self-propelled, characterized by comprising: a traveling operation control means for moving the moving body by utilizing the inertial force of the piezoelectric element and the frictional force received by the moving body when the piezoelectric element expands and contracts in the axial direction. apparatus.