Insertion equipment, attachment tool and drive force transmission unit

In an insertion equipment, a cover film forming part of an outer periphery surface of an insertion section has flexibility and is formed of a resilient material. In the insertion section, a protrusion protruding to an outer periphery side is covered by the cover film from the outer periphery side, and the protrusion moves around a longitudinal axis with respect to the cover film due to a transmission of a drive force for rotating an attachment tool. A ring member of the attachment tool is attached to the outer periphery side of the cover film in a state that the protrusion is pressed to an inner periphery side by the ring member via the cover film, and is rotatable around the longitudinal axis with respect to the cover film.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to insertion equipment including an insertion tool and an attachment tool attached to the insertion tool's insertion section. The present invention further relates to an attachment tool provided in the insertion equipment, and a drive force transmission unit configured to transmit a drive force from the insertion section to the attachment tool in the insertion equipment.

2. Description of the Related Art

International Publication No. 2013/038720 discloses a spiral unit (attachment tool) attached to an outer periphery surface of an insertion section of an endoscope (insertion tool). The spiral unit is detachably attached to the insertion section in a state in which it covers the insertion section from an outer periphery side, and includes a spiral fin extending spirally with a longitudinal axis as the center. In the insertion section, a rotor body is attached to a base portion. Also in the insertion section, a cylindrical cover film is attached to the base portion, the cover film covering the rotor body from the outer periphery side. Due to the drive force transmitted in a state in which the spiral unit is attached to the insertion section, the rotor body rotates about the longitudinal axis and presses the spiral unit through the cover film. In this manner, the drive force is transmitted from the rotor body of the insertion section to the spiral unit, causing the spiral unit to rotate about the longitudinal axis. At this point, the spiral unit rotates around the longitudinal axis toward the side where the rotor body rotates.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the invention, insertion equipment including: an insertion tool which includes an insertion section extending along a longitudinal axis; an attachment tool which is attached to an outer periphery surface of the insertion section, part or all of the attachment tool being configured to rotate around the longitudinal axis due to a drive force transmitted from the insertion section; a cover film which forms part of the outer periphery surface of the insertion section, the cover film having flexibility and being formed of a resilient material; one or more protrusions which protrude to an outer periphery side, and which are covered by the cover film from the outer periphery side in the insertion section, the one or more protrusions being configured to move around the longitudinal axis with respect to the cover film due to a transmission of the drive force for rotating the attachment tool; and a ring member which forms part of an inner periphery surface of the attachment tool, and which is attached to the outer periphery side of the cover film in a state in which the protrusions are pressed to a side toward the longitudinal axis by the ring member via the cover film, the ring member being rotatable around the longitudinal axis with respect to the cover film.

According to one another aspect of the invention, an attachment tool which is used together with an insertion tool, the insertion tool including an insertion section, a cover film, and one or more protrusions, the insertion section extending along a longitudinal axis, the cover film forming part of an outer periphery surface of the insertion section, the cover film having flexibility and being formed of a resilient material, the one or more protrusions protruding to an outer periphery side, the protrusions being covered by the cover film from the outer periphery side in the insertion section, the protrusions being configured to move, due to a transmission of a drive force, around the longitudinal axis with respect to the cover film, the attachment tool being attached to the outer periphery surface of the insertion section, the attachment tool including: a driven section which is configured to rotate around the longitudinal axis due to the drive force transmitted through the insertion section; and a ring member which is coupled to the driven section, and which forms part of an inner periphery surface of the attachment tool, the ring member being attached to the outer periphery side of the cover film in a state in which the protrusions are pressed to an inner periphery side by the ring member via the cover film, the ring member being rotatable around the longitudinal axis with respect to the cover film.

According to one another aspect of the invention, a drive force transmission unit including: a cover film which extends along a central axis, the cover film having flexibility and being formed of a resilient material; one or more protrusions which protrude to an outer periphery side, and which are covered by the cover film from the outer periphery side, the one or more protrusions being configured to move, due to a transmission of a drive force, around the central axis with respect to the cover film; and a ring member which is attached to the outer periphery side of the cover film in a state in which the protrusions are pressed by the ring member via the cover film to an inner periphery side, the ring member being rotatable around the central axis with respect to the cover film.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

A first embodiment of the present invention will be described with reference toFIGS. 1 to 5.FIG. 1is a view showing the insertion equipment1. As shown inFIG. 1, the insertion equipment1includes an endoscope2that is an insertion tool, and a spiral unit10that is an attachment tool. The endoscope2includes an insertion section3, the insertion section3having a longitudinal axis C as a central axis. One side of a direction along the longitudinal axis C (longitudinal axial direction) is a distal side (arrow C1side inFIG. 1), and a side opposite to the distal side is the proximal side (arrow C2side inFIG. 1). The insertion section3extends along the longitudinal axis C, from the proximal side to the distal side. The insertion section3has an outer periphery surface7. The endoscope2includes an operation section5provided on the proximal side with respect to the insertion section3. To the operation section5, one end of a universal cord6is connected.

The insertion equipment1is used together with peripheral devices. The peripheral devices include an image processing device (not shown) such as an image processor, a light source device (not shown) such as a lamp, a drive control device (not shown) including an electric power source, a conversion circuit, a processor and a storage medium, an operation input device (not shown) such as a foot switch, and a display device (not shown) such as a monitor. The other end of the universal cord6is detachably connected to, for example, the light source device that is one of the peripheral devices.

In the endoscope2, an imaging cable (not shown) and a light guide (not shown) extend through an interior of the insertion section3, an interior of the operation section5, and an interior of the universal cord6. An imaging element (not shown) such as a CCD is provided inside a distal portion of the insertion section3. The imaging element takes images of an imaging subject through an observation window (not shown), the observation window being provided on the outer surface of the distal portion of the insertion section3. Then, via the imaging cable, imaging signals are transmitted to the image processing device (not shown), and then the image processing device performs the image processing. In this manner, the image processing device generates the images of the imaging subject, and then the generated images of the imaging subject is displayed at the display device (not shown). Light emitted from the light source device (not shown) is further guided through the light guide. Then, from an illumination window (not shown) provided on the outer surface of the distal portion of the insertion section3, the guided light is irradiated on the imaging subject.

The spiral unit10is formed into a cylindrical shape. In the insertion equipment1, the spiral unit (attachment tool)10is detachably attached to the outer periphery surface7of the insertion section3in a state in which the insertion section3is inserted through the spiral unit10. In a state in which the spiral unit10is attached to the insertion section3, the central axis of the spiral unit10is approximately coaxial with the longitudinal axis C of the insertion section3. The spiral unit10has an inner periphery surface11. The spiral unit10further includes a driven section (driven object)12to be driven, and a connector part (connector)13connected to the insertion section3. The driven section12is connected to the distal side of the connector part13. The driven section12includes a cylindrical tube main body15extending along the longitudinal axis C (central axis of spiral unit10), and a spiral fin16protruding to the outer periphery side on the outer periphery surface of the tube main body15. The spiral fin16extends spirally about the longitudinal axis C (central axis of the spiral unit10).

The connector part13includes a cylindrical ring member17forming part of the inner periphery surface11of the spiral unit10, and a cover18covering the outer periphery side of the ring member17. The ring member17is formed of an elastomer material or a resilient resin material. Therefore, the ring member17is elastically deformable.FIG. 2is a view showing the connector part13of the spiral unit10in a state where the spiral unit10is detached from the insertion section3, in a cross-section that intersects (approximately perpendicularly) the central axis (longitudinal axis C) of the spiral unit10. The ring member17, as shown inFIG. 2, has an inner diameter D0in a state in which the spiral unit10is detached from the insertion section3. The ring member17further has an inner peripheral length L0. Since the ring member17is cylindrical, the inner periphery surface of the ring member17is formed into a smooth curved surface. In the embodiment, the entire spiral unit (attachment tool)10including the driven section (driven object)12and the connector part (connector)13is rotatable about the longitudinal axis C.

As shown inFIG. 1, in the endoscope2, a motor casing21is attached to the operation section5. Inside the motor casing21, an electric motor22is provided as a drive source. To the electric motor22, one end of an electric wiring (not shown) is connected. The electric wiring is connected to the drive control device (not shown) being one of the peripheral devices, running through the interior of the operation section5and through the interior of the universal cord6. The drive control device controls the supply state of the drive electric power to the electric motor22based on the operation input at the operation input device (not shown), and controls the drive state of the electric motor22. Supplying drive electric power to the electric motor22drives the electric motor22and generates a drive force causing the spiral unit10(driven section12) to rotate (orbit) about the longitudinal axis C (central axis of spiral unit10).

The insertion section3includes a distal-side flexible tube section23, and a proximal-side flexible tube section25located on the proximal side with respect to the distal-side flexible tube section23. The proximal end of the proximal-side flexible tube section25is connected to the operation section5. A base portion (stator)27formed of a hard material is provided between the distal-side flexible tube section23and the proximal-side flexible tube section25. In other words, the distal-side flexible tube section23is connected to the proximal-side flexible tube section25via the base portion27. In a state in which the spiral unit10is attached to the insertion section3, the outer periphery side of the base portion27is covered by the connector part13(proximal portion of spiral unit10) of the spiral unit10, and the spiral unit10extends from a region located on the outer periphery side of the base portion27toward the distal side. The outer periphery side of the distal-side flexible tube section23is then covered by the driven section12. Note that the number of members forming the base portion (stator)27is not limited, and that the base portion27may be formed from one member or from a plurality of members.

FIGS. 3 and 4are views showing a configuration of the base portion27and its vicinity in a state in which the spiral unit10is attached to the outer periphery surface7of the insertion section3.FIG. 3shows a cross-section approximately parallel to the longitudinal axis C, andFIG. 4shows a cross-section that intersects (approximately perpendicularly) the longitudinal axis C and that extends through the connector part13. As shown inFIGS. 1, 3, and 4, a drive gear31is disposed inside the insertion section3. The drive gear31is attached to the base portion27. Inside the proximal-side flexible tube section25, a drive shaft32extends from the proximal side to the distal side. The central axis of the drive shaft32is approximately parallel to the longitudinal axis C. The proximal end (one end) of the drive shaft32is connected to a gear train33inside the operation section5. The gear train33is connected to the electric motor22that is the drive source. In other words, the drive shaft32is connected to the electric motor22via the gear train33. Further, the distal end of the drive shaft32is connected to the drive gear31. As the electric motor22is driven, the drive force is transmitted via the gear train33to the drive shaft32so as to cause the drive shaft32to rotate around the central axis of the drive shaft32. In this manner, the drive force is transmitted to the drive gear31so as to cause the drive gear31to rotate.

The insertion section3includes a rotor body (rotor)35attached to the base portion27from the outer periphery side. The rotor body35is rotatable with respect to the base portion27about the longitudinal axis C. The rotor body35includes a rotor base36having a cylindrical shape, and (in the embodiment: six) rollers (rotation members)37attached to the rotor base36. On the inner periphery surface of the rotor base36, an inner peripheral gear38is formed. The inner peripheral gear38extends across the entire periphery around the longitudinal axis C. The drive gear31engages with the inner peripheral gear38. Therefore, as the drive gear31rotates, the drive force is transmitted to the rotor body35, and the rotor base36and the rollers37rotate (revolve) together around the longitudinal axis C.

As shown inFIGS. 1, 3 and 4, each of the rollers37is rotatable (pivot able) with respect to the rotor base36about its corresponding rotation axis (the corresponding one of P). Each of the rollers37forms a corresponding protrusion (the corresponding one of41). Each of the protrusions41protrudes to the outer periphery side of the rotor body35. As the drive force is transmitted to the rotor body35and thereby causes the rotor body35to rotate around the longitudinal axis C with respect to the base portion27, each of the protrusions41moves around the longitudinal axis C with respect to the base portion27. The protrusions41(rollers37) are arranged to be spaced apart from each other around the longitudinal axis C.

The insertion section3is provided with a cover film42that covers, from the outer periphery side, the rotor body35including the protrusions41. The cover film42extends along the longitudinal axis C (central axis of the cover film). The cover film is formed of a resilient material, such as a rubber, and has flexibility. Part of the outer periphery surface7of the insertion section3is formed of the cover film42. Both the proximal end and the distal end of the cover film42are fixed via adhesion or the like to the outer periphery surface of the base portion (stator)27. This regulates the rotation around the longitudinal axis C (around the central axis of the cover film42) with respect to the base portion27of the cover film (coat)42. Therefore, as the drive force is transmitted to the rotor body35, and thereby causes the rotor body35to rotate around the longitudinal axis C with respect to the cover film42, the protrusions41move, together with the rotor base36, around the longitudinal axis C with respect to the cover film42.

Each of the protrusions41presses the cover film42from the inner periphery side to the outer periphery side. In this manner, the cover film42is elastically deformed by the pressing force from the protrusions41, and protrudes to the outer periphery side in locations (sites) where the cover film42is pressed by the respective protrusions41. By this, in each of the locations where the cover film42is pressed by the protrusions41, an apex (corresponding one of E) protruding to the outer periphery side is formed on the outer periphery surface of the cover film42. By connecting, in the cross-section that intersects (approximately perpendicularly) the longitudinal axis C, each of the apexes E in a straight line to its adjacent apex (corresponding one of E) around the longitudinal axis C, a hexagon (polygon) H1is formed. Since the protrusions41in the embodiment are arranged at approximately equal intervals around the longitudinal axis C, the apexes E are also arranged at approximately equal intervals around the longitudinal axis C. The hexagon H1is therefore a regular hexagon (regular polygon) having the longitudinal axis C as the center. Each of the apexes E forms the vertex of the hexagon H1. Each of the straight lines connecting each of the apexes E to its adjacent apex (corresponding one of E) around the longitudinal axis C forms an edge of the hexagon H1.

Here, in the cross-section that intersects the longitudinal axis C and that passes through the protrusions41, the outer periphery surface of the cover film42has approximately the same shape as the above-mentioned hexagon H1, and the outer peripheral length of the cover film42has approximately the same length as a peripheral length L1of the hexagon H1. The hexagon H1in the embodiment is a regular hexagon having the longitudinal axis C as the center. Thus, the peripheral length L1of the hexagon H1is expressed by Equation (1) to define a radius R1of a circumcircle H2of the hexagon H1. Note that the circumcircle H2is approximately the same as a trajectory circle through which each of the apexes E formed in the cover film42runs in the move of the protrusions41around the longitudinal axis C, and that the radius R1is the same as the distance from the longitudinal axis C to each of the apexes E. The peripheral length L1of the hexagon H1is expressed by Equation (2) to define both a pitch radius R2of each of the rollers37being the distance from the longitudinal axis C to the axis (corresponding on of P) of each of the rollers37, and a peripheral length S1of one roller37.
L1≈6·R1  (1)
L1≈6·R2+S1  (2)

In a state in which the spiral unit (attachment tool)10is attached to the outer periphery surface7of the insertion section3, in other words, in a state in which the connector part13is connected to the insertion section3, the ring member17is attached to the outer periphery side of the cover film42. The spiral unit10including the ring member17is rotatable around the longitudinal axis C with respect to the base portion27and the cover film42. The inner peripheral length L0of the ring member17is longer than the peripheral length L1of the aforementioned hexagon (regular polygon) H1. Also, the inner peripheral length L0of the ring member17is shorter than the peripheral length L2of the circumcircle H2of the hexagon H1. As described above, in the embodiment, an even number of protrusions41(apexes E) is provided, and the hexagon H1is a regular hexagon having the longitudinal axis C as a center. Therefore, since the inner peripheral length L0is longer than the peripheral length L1but shorter than the peripheral length L2, the inner diameter D0of the ring member17, in a state where the spiral unit10is detached from the insertion section3, is larger than the width across flats A1of the hexagon H1but smaller than the width across corner A2of the hexagon H1.

Since the inner peripheral length L0is shorter than the peripheral length L2of the circumcircle H2(since the inner diameter D0is smaller than the width across corner A2), the ring member17is pressed, in a state in which the ring member17is attached to the outer periphery side of the cover film42, from each of the protrusions41to the outer periphery side via the cover film42, by which the ring member17elastically deforms. Therefore, the ring member17presses, in a state in which the spiral unit10is attached to the insertion section3, each of the protrusions41via the cover film42to the inner periphery side (side toward longitudinal axis C). The inner peripheral length L0is longer than the peripheral length L1of the hexagon that is approximately the same length as the outer peripheral length of the cover film42. Thus, in a state where the ring member17is attached to the outer periphery side of the cover film42, the ring member17is in contact with the cover film (coat)42from the outer periphery side only in the regions where the apexes E (protrusions41) are located and the vicinities thereof around the longitudinal axis C. In the regions away from any of the apexes E, such as in the regions between each of the apexes E and the adjacent apex (corresponding one of E) around the longitudinal axis C, the ring member17is away from the cover film42and not in contact with the cover film42.

Note that the inner peripheral length L0of the ring member17is shorter than the peripheral length L2of the circumcircle H2and the ring member17is elastically deformed by each of the protrusions41pressing the ring member17, so that, in the regions away from any of the apexes E around the longitudinal axis C, the inner periphery surface of the ring member17is located on the inner periphery side with respect to the circumcircle H2of the hexagon H1. However, since the difference between the inner peripheral length L0of the ring member17and the peripheral length L2of the circumcircle H2(i.e., the difference between the inner diameter D0and the width across corner A2) is very small, the displacement of the inner periphery surface of the ring member17with respect to the circumcircle H2of the hexagon H1toward the inner periphery side at the locations away from any of the apexes E around the longitudinal axis C is minute. Therefore, inFIG. 4, the displacement of the inner periphery surface of the ring member17with respect to the circumcircle H2of the hexagon H1at the locations away from any of the apexes E around the longitudinal axis C is not shown, and the inner periphery surface of the ring member17is shown as having approximately the same shape as the circumcircle H2.

FIG. 5is a view explaining the configuration for transmitting the drive force to rotate the spiral unit10(driven section12) around the longitudinal axis C from the protrusions41(rotor body35) to the connector part13of the spiral unit10. In the embodiment, the drive force transmission unit40configured to transmit the drive force from the insertion section3to the connector part13of the spiral unit (attachment tool)10is formed of the protrusions41, the cover film42, and the ring member17.

When the rotor body35shown inFIGS. 1, 3 and 4rotates with respect to the cover film42toward one side (side of arrow Y1) around the longitudinal axis C, each of the rollers37rotates counterclockwise around its own rotation axis P. As shown inFIG. 5, each of the protrusions41moves (clockwise inFIG. 5) around the longitudinal axis C toward one side (arrow X1inFIG. 5). In this manner, the location (site) pressed by each of the protrusions41in the cover film42also moves to the side where the protrusions41move around the longitudinal axis C. In other words, each of the apexes E, which protrude to the outer periphery side in the cover film42and at which the ring member17is in contact with the cover film42, moves toward the side where the protrusions41move around the longitudinal axis C (side of arrow Y1inFIG. 5). As the apexes E of the cover film42pressed by the protrusions41move around the longitudinal axis C, a traveling wave is generated in the cover film (coat)42. The traveling wave proceeds to the side where the protrusions41move around the longitudinal axis C (arrow X2inFIG. 5).

As the traveling wave moves, each point on the outer periphery surface of the cover film42moves elliptically (arrows X3inFIG. 5). The rotation of the elliptical motion is counter to the travel direction of the protrusions41(travel direction of the traveling wave). InFIG. 5, as each of the protrusions41moves clockwise around the longitudinal axis C, each point on the outer periphery surface of the cover film42moves elliptically counterclockwise. The outer periphery surface of the cover film42is in contact with the ring member17in the locations (of the apexes E protruding to the outer periphery side in the cover film42) where pressed by each of the protrusions41to the outer periphery side. Therefore, at the apexes E of the cover film42, due to the elliptical motion of the outer periphery surface of the cover film42, a force (frictional force) F1acts on the ring member17toward the side opposite to the side where the traveling wave travels, the ring member17being in contact from the outer periphery side. Due to the force F1, the spiral unit (attachment tool)10including the ring member17rotates around the longitudinal axis C to the side opposite to the side where the traveling wave is making the motion (arrow X4inFIG. 5). Since the traveling wave inFIG. 5moves clockwise (on the side of arrow Y1) around the longitudinal axis C, the ring member17and the driven section12rotate counterclockwise (on the side of arrow Y2) around the longitudinal axis C.

Note that the traveling wave is likewise generated by a piezoelectric element in a stator of an ultrasonic motor. Each point on the stator's outer surface makes elliptical motions due to the motion of the traveling wave, and the rotor in contact with the stator's outer surface is caused to rotate toward the side opposite to the side where the traveling wave moves. Therefore, the principle of rotating the spiral unit10toward the side opposite to the side where the traveling wave is making the motion by the traveling wave of the embodiment is similar to the principle of rotating the rotor with respect to the stator by the traveling wave generated in the ultrasonic motor's stator.

As described above, each of the protrusions41(rollers37) of the embodiment moves to one side (arrow Y1side) around the longitudinal axis C, so that a drive force is transmitted to the ring member17, and the spiral unit10including the ring member17moves to the side (arrow Y2side) opposite to the side where the protrusions41move around the longitudinal axis C. Similarly, even when each of the protrusions41moves to the other side (arrow Y2side) around the longitudinal axis C, the drive force is transmitted to the ring member17, and the spiral unit10including the ring member17moves to the side (arrow Y1side) opposite to the side where the protrusions41move around the longitudinal axis C.

Next, the functions and advantages of the insertion equipment1of the embodiment will be described. When observing the lumen using the insertion equipment1, the spiral unit (attachment tool)10is attached to the insertion section3of the endoscope (insertion tool)2, and the insertion section3and the spiral unit10are inserted into the lumen. By performing an operation input using the operation input device (not shown), the electric motor (drive source)22is driven, and, as described above, the drive force is transmitted to the spiral unit10via the insertion section3. As a result, the spiral unit10rotates about the longitudinal axis C. When the spiral unit is rotated in a state in which the spiral fin16is pressed by the wall of the lumen to the inner periphery side, a propulsion force to the distal side or the proximal side (one of the sides in the direction along the longitudinal axis C) acts upon the insertion section3and the spiral unit10. The propulsion force improves the mobility of the insertion section3in the lumen. Since, here, each of the rollers37is rotatable about its own rotation axis (corresponding one of P), the friction between the rollers37and the cover film (cover tube)42is reduced.

In the embodiment, in a state where the protrusions41are pressed via the cover film42to the inner periphery side, a cylindrical ring member17is attached to the outer periphery side of the cover film42, and the inner periphery surface of the ring member17is formed into a smoothly curved surface. In other words, since the drive force in the embodiment is transmitted from the protrusions to the ring member17as described above, in the connector part13of the spiral unit (attachment tool)10including the ring member17, it is not necessary to provide protrusions (protruding portions) or the like that protrudes to the inner periphery side and is pressed by the protrusions41. As a result, the configuration of the connector part13is simplified, and the labor and cost of manufacturing the spiral unit (attachment tool)10are reduced. Since the connector part13is not provided with the protrusions protruding to the inner periphery side, the outer diameter of the spiral unit10including the connector part13can be reduced in diameter. As a result, in the portion of the insertion equipment1, in which the spiral unit10covers the outer periphery side of the insertion section3, the outer diameter can be reduced.

The inner periphery surface of the ring member17being a smooth curved surface is in contact with the apexes E against the cover film42. Therefore, in a state in which the ring member17is attached to the outer periphery side of the cover film42, the load from the ring member17(spiral unit10) to the cover film42is reduced. In this manner, the concentration of stress on the cover film42is reduced, and the durability of the cover film42is improved.

When the load to the driven section (driven object)12, for example, the pressing force from the lumen wall or the like to the driven section12, becomes excessively large, the inner periphery surface (contact surface to the cover film42) of the ring member17slips with respect to the apexes E of the cover film42because the inner periphery surface of the ring member17being the smooth curved surface is in contact with the cover film (coat)42. As a result, even when each of the protrusions41moves around the longitudinal axis C by the drive force transmitted from the electric motor22and the traveling wave is generated in the cover film42, a drive force from the protrusions41is not transmitted through the cover film42to the ring member17in the drive force transmission unit40. Therefore, even when the protrusions41move around the longitudinal axis C, the spiral unit10including the driven section12does not rotate around the longitudinal axis C. Therefore, in the embodiment, in a state where an excessive load is applied to the driven section12, the drive force is prevented from being transmitted to the spiral unit10, and the spiral unit10is prevented from rotating around the longitudinal axis C. In other words, a mechanical torque limit is formed by the drive force transmission unit40.

In the drive force transmission unit40, the reduction ratio ε of the rotational speed of the ring member17with respect to the motion speed of each of the protrusions41(apexes E) is expressed by Equation (3), using the inner peripheral length L0of the aforementioned ring member17and the peripheral length L1of the hexagon H1having approximately the same length as the outer peripheral length of the cover film42.
ε=(L1−L0)/L0  (3)

Here, the inner peripheral length L0of the ring member17is longer than the peripheral length L1of the hexagon H1. Therefore, the reduction ratio ε is a negative value. The fact here that the reduction ratio ε in the Equation (3) is a negative value shows that the ring member17rotates toward the side opposite to the side where the protrusions41(apexes E) move around the longitudinal axis C. Equation (3) further shows that the absolute value of the reduction ratio ε is smaller than 1. Therefore, the rotational speed of the ring member17is decelerated with respect to the motion speed of each of the protrusions41(apexes E). As the rotation speed of the ring member17is decelerated with respect to the motion speed of the protrusions41, the rotation torque for rotating the ring member17is amplified with respect to the rotation torque for moving the protrusions41. For example, when the reduction ratio ε is −0.9 and the protrusions41move around the longitudinal axis C at 50 rpm, the ring member17rotates toward the side opposite to the side where the protrusions41move around the longitudinal axis C at 45 rpm.

Since the rotational speed of the ring member17is decelerated with respect to the motion speed of the protrusion41as described above (because the rotary torque of the ring member17is amplified from the protrusions41), it is possible to increase the rotation speed of the rotor body35and to reduce the rotary torque of the rotor body35. In other words, even if the rotary torque of the rotor body35is small, the rotary torque of the spiral unit20can be increased. Therefore, in the configuration in which the drive force is transmitted from the electric motor22to the rotor body35, it is possible to reduce the speed reduction amount (i.e., the torque amplification amount). In this manner, simplification and miniaturization of the configuration for transmitting the drive force from the electric motor22to the rotor body35can be realized.

Note that the number of protrusions41(rollers37) is not limited to the aforementioned embodiments. As long as it is one or more, the number of protrusions41is not limited to six. However, the number of protrusions41is preferably between 5 and 8.

In the aforementioned embodiment and the like, each of the rollers37forms a corresponding one of the protrusions41, but it is not limited thereto. The rollers37thus do not necessarily have to rotate around the rotation axis P. In a modification, rollers (37) are not provided and the rotor body (35) is formed integrally solely from the rotor base (36). Each of the protrusions (41) is formed in the rotor base (36). In the modification, a traveling wave is likewise generated in the cover film (42) by the protrusions (41) moving around the longitudinal axis C. The ring member (17) rotates around the longitudinal axis C toward the side opposite to the side where the protrusions (41) and the traveling wave are making the motion.

Further, in the aforementioned embodiment and the like, the inner peripheral gear38is formed in the rotor base36of the rotor body35, but it is not limited thereto. In a modification (not shown), the inner peripheral gear (38) engaging with the drive gear (31) is formed on the inner periphery surface of a cylindrical member, the cylindrical member being a separate member from the rotary body (35). The rotor body (35) includes a rotor base (36) as a supporting member, and one or more rollers (37), and the rollers (37) are in contact with the outer periphery surface of the cylindrical member from the outer periphery side. In the modification, the drive force is transmitted from the drive gear (31) to the cylindrical member, and the cylindrical member rotates around the longitudinal axis C, whereby the drive force is transmitted from the cylindrical member to the rollers (37) of the rotor body (35). As a result, each of the rollers (37) rotates (pivots) about the rotation axis (P) approximately parallel to the longitudinal axis (C) and moves (revolves) around the longitudinal axis (C). In other words, each of the rollers (37) makes a planetary motion. At this point, the rollers (37) rotate toward the side where the cylindrical member rotates around the longitudinal axis (C). As the rollers (37) move around the longitudinal axis (C), the rotor body (35) rotates around the longitudinal axis (C).

According to the modification, each of the rollers (37) also forms a corresponding one of protrusions (41). As described above, each of the protrusions (41) moves around the longitudinal axis C due to the rotation of the rotor body (35). In the modification, a traveling wave is likewise generated in the cover film (42) by the motion of the protrusions (41) around the longitudinal axis C. The ring member (17) then rotates around the longitudinal axis C toward the side opposite to the side where the protrusions (41) and the traveling wave are moving.

In the aforementioned embodiment and the like, the spiral unit (10) has been described as an example of the attachment tool that was attached to the insertion section (3), but the attachment tool is not limited to the spiral unit (10). For example, in the attachment tool according to a modification, a belt member comes into contact with the driven section (12) from the outer periphery side. In this case, when the drive force is transmitted to the ring member (17) and the ring member (17) and the driven section (12) rotate around the longitudinal axis (C), the drive force is transmitted from the driven section (12) to the belt member, and the belt member moves to the proximal side or to the distal side. In other words, according to the modification, as the drive force is transmitted, part of the attachment tool is rotated around the longitudinal axis (C).

In the aforementioned embodiments and the like, the endoscope (2) has been described as an example of the insertion tool, but the insertion tool is not limited to the endoscope (2). For example, the aforementioned configuration may be applied to insertion equipment in which a manipulator is used as the insertion tool.

In the aforementioned embodiment and the like, the insertion tool (2) includes the insertion section (3) extending along the longitudinal axis (C), the attachment tool (10) is attached to the outer periphery surface (7) of the insertion section (3), and, as the drive force is transmitted from the insertion section (3), part or all rotates around the longitudinal axis (C). The cover film (42) forms part of the outer periphery surface (7) of the insertion section (3), has flexibility, and is formed of a resilient material. The insertion section (3) includes one or more protrusions (41) protruding to the outer periphery side, and the protrusions (41) are covered by the cover film (42) from the outer periphery side, and, as the drive force for rotating the attachment tool (10) is transmitted, the protrusions (41) move around the longitudinal axis (C) with respect to the cover film (42). The attachment tool (10) includes the ring member (17) forming part of the inner periphery surface (11), and, in a state in which the protrusions (41) are pressed via the cover film (42) to the inner periphery side, the ring member (17) is attached to the aforementioned outer periphery side of the cover film (42). The ring member (17) is rotatable around the longitudinal axis (C) with respect to the cover film (42).