JP2001258826A - Endoscopic control cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the sliding resistance between a transmission coil and a flexible sleeve and also minimize the fluctuating width of the leading length of the transmission coil from the flexible sleeve by bending by setting the wire diameter of the transmission coil substantially the same, and forming the transmission coil into a minor coil part with a small outer diameter in an angle part and a major coil part with a large diameter in a soft part. SOLUTION: This control cable 41 for remotely moving a movable lens 31a in the optical axial direction by a motor 51 comprises the transmission coil 43 inserted into the flexible sleeve 42. The transmission coil 43 is formed of the coil of a metal wire rod having the same wire diameter, which forms the minor coil 43a in the angle part 3b and the major coil part 43b in the soft part 3c. The outer diameter of the minor coil part 43a is set smaller than the dimension of the minor axis when the flexible sleeve 42 is most flattened. The minor coil part 43a and the major coil part 43b are mutually connected through a joint member 57 provided in the position of the connection part of the angle part 3b to the soft part 3c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope used for medical purposes and the like, in which one end is connected to the movable member so as to remotely drive a movable member provided at the distal end of an insertion portion. And a control cable for an endoscope, the other end of which is connected to a drive unit provided in a main body operation unit.

[0002]

2. Description of the Related Art In general, an endoscope used for medical purposes or the like is a universal endoscope which is detachably connected to an insertion portion into a body cavity, a light source device, and the like, to a main body operation portion which is grasped and operated by an operator. It is roughly configured by providing a series of cords. Due to its structure and function, the insertion portion is composed of a distal end hard portion, an angle portion, and a flexible portion from the distal end side, and the flexible portion has most of the length from the side of the connecting portion to the main body operation portion. And bends in any direction along. The distal end hard portion is provided with an illumination portion, an observation portion, and the like on the distal end surface thereof, and has an opening for a treatment tool lead-out portion for leading a treatment tool such as forceps. By bending the angle portion by remote operation from the main body operation portion side, the hard distal end portion can be directed in an arbitrary direction.

As described above, at least the illuminating section and the observation section are provided on the distal end hard section, and the illuminating section faces the exit end of a light guide made of an optical fiber bundle. Through the main body operation unit and into the universal cord. Further, an objective optical system is mounted on the observation unit. When the objective optical system is configured as an electronic endoscope, a solid-state imaging device is arranged at an image forming position in the objective optical system. Here, the observation unit is generally arranged at a substantially central position in a longitudinal section of the hard distal end portion, and one or a plurality of illumination units are provided at positions close to the observation unit.

The objective optical system provided in the observation section includes an objective lens group, and this objective lens group is usually composed of a plurality of lenses. Depending on the site to be observed, the purpose of the treatment, and the like, it is desirable to change the depth of focus for the observation target, the imaging magnification, the viewing angle, and the like. Therefore, it is conventionally known that one or a plurality of lenses in the objective lens group is formed as a movable lens movable in the optical axis direction and the movable lens is moved.

Various types of driving means for moving the movable lens in the optical axis direction have been proposed, but a control cable is generally used.
Connect a movable lens to the distal end of this control cable, and extend the base end thereof into the main body operation unit,
The movable lens is configured to be moved in the optical axis direction by remote control. As a specific configuration of the control cable, a cable in which a transmission member is inserted into a flexible sleeve can be cited. Here, since the driving of the movable lens is a linear movement, an operating wire for pushing and pulling can be used as the transmission member provided in the flexible sleeve. However, when using the operation wire, a spring acts on the operation wire to urge the operation wire in the pulling direction, and the movable lens is moved by pulling the operation wire in a direction against the urging force of the spring. However, there is a problem in that the positioning accuracy is not sufficiently obtained and the operation wire is elongated.

In consideration of the above points, there is known a transmission member using a flexible shaft for transmitting a rotational force. The flexible shaft is composed of a transmission coil in which a metal wire is wound in a tight coil shape. In order to convert the rotation by the transmission coil into a linear motion of the movable lens, for example, the tip of the transmission coil is connected to a screw shaft, and the screw shaft is rotatably supported by a shaft support member. A nut is connected to and provided on the movable lens frame on which is mounted, and the nut is screwed to the screw shaft. Accordingly, the position of the movable lens can be strictly controlled, and the movable lens can be held at an arbitrary position, which is extremely advantageous from the viewpoint of operability.

[0007]

The angle portion constituting the insertion portion of the endoscope is for directing the hard distal end portion in a desired direction, and is provided by remote control from an angle operation device provided in the main body operation portion. It is configured to be curved. The bending of the angle portion is mainly for changing the viewing field of the endoscope. The insertion portion is inserted into a narrow body cavity to perform examinations and diagnoses. In order to smoothly and surely change the observation field of view even in a narrow body cavity, it is desirable that the entire length of the angle portion be as short as possible. In addition, in order to minimize the occurrence of blind spots in the observation field, the bending angle must be as large as possible. Therefore, when the angle portion is bent to the maximum bending angle state, the radius of curvature is extremely small, and it is configured to be able to bend sharply, for example, at an angle of 180 ° or near. In addition, since the insertion path in the body cavity has a complicatedly curved shape, the flexible section connected to the angle section has flexibility in the bending direction, and this flexible section can follow the bending of the insertion path and be flexible. It is configured to bend in the direction of.

When the insertion portion is inserted into the body cavity, at least the flexible portion is bent to some extent. Therefore, when the transmission coil inserted through the inside of the flexible sleeve is driven to rotate, the transmission coil slides on the inner surface of the flexible sleeve. However, the rotational force of the transmission coil is smoothly transmitted to the tip as long as the flexible sleeve has a small curvature when bent and is gently bent.

However, in a state where the angle portion is bent to the maximum bending state, the flexible sleeve follows and bends, so that the flexible sleeve is deformed to be flat. On the other hand, since the transmission coil is formed by winding a metal wire, it has flexibility in the bending direction, but its sectional shape does not change. Moreover, the rigidity against bending is higher in the transfer coil than in the flexible sleeve. Therefore, when the angle portion is in the maximum bending state, the transmission coil is in a state of being pressed against the flexible sleeve. When the transmission coil is rotationally driven in this state, the transmission coil is strongly pressed against the inner surface of the flexible sleeve, so that the sliding resistance against the rotation is increased, and the driving torque is significantly increased. As a result, if the rotation of the transmission coil is driven by, for example, a motor provided in the main body operation unit, the load on the motor increases. For this reason, it is necessary for the motor that drives the transmission coil to reliably apply a rotational force to the tip even when the load is maximum, that is, when the angle portion is in the maximum bending state. For this reason, a large motor must be used, and as a result, inconveniences such as an increase in the size of the main body operation unit and an increase in the weight, which increases the burden on the operator, and the like occur. Similarly, when the transmission coil is rotated manually, the operability is significantly reduced because the resistance to the rotation is increased.

The above-described increase in the driving torque of the transmission coil is caused by the sliding friction between the transmission coil and the flexible sleeve. Therefore, if the diameter difference between the transmission coil and the flexible sleeve is increased, this is increased. The sliding resistance between the transfer coil and the flexible sleeve can be reduced. For example, the inner diameter of the flexible sleeve, even if the angle portion becomes the maximum curved state and the flexible sleeve is flattened and deformed into an elliptical shape, at least a state larger than the outer diameter of the transmission coil, that is, the flexible sleeve By making the outer diameter of the transmission coil smaller than the dimension in the short axis direction, the sliding resistance during rotation of the transmission coil can be significantly reduced.

When the control cable is bent, the transfer coil moves in the axial direction with respect to the flexible sleeve. In other words, in the bent state, the length of the transfer coil in the flexible sleeve changes depending on whether the transfer coil follows the inside or outside of the bent portion on the inner surface of the flexible sleeve. Therefore, if the transfer coil cannot be moved in the axial direction with respect to the flexible sleeve, the transfer coil meanders inside the flexible sleeve and the sliding resistance during rotation increases. is there. Therefore, when the control cable is bent,
The length of the transfer coil leading out of the flexible sleeve must be allowed to vary. For this reason, the absorbing portion that allows the change of the lead-out length is provided on the drive portion side, but the larger the diameter difference between the transfer coil and the flexible sleeve, the larger the fluctuation width of the lead-out length of the transfer coil. Becomes larger. Therefore, problems such as an increase in the size of the absorption section provided in the main body operation section and an increase in weight occur.

The present invention has been made in view of the above points, and an object of the present invention is to drive a movable member provided at the distal end of an insertion portion by using a transfer coil and a flexible sleeve. It is an object of the present invention to minimize the sliding resistance between them and to minimize the fluctuation width of the length of the transfer coil derived from the flexible sleeve due to bending.

[0013]

In order to achieve the above-mentioned object, the present invention provides a movable member mounted on a distal end of an insertion portion which is provided in the order of a distal hard portion, an angle portion, and a soft portion from the distal end side. In order to drive by remote control from the main body operation unit connected to the base end of the insertion unit, a metal wire is spirally wound, one end is connected to the movable member, and the other end is connected to the rotation drive unit. An endoscope control cable including a connected transmission coil and a flexible sleeve through which the transmission coil is inserted and having both ends fixed, wherein the transmission coil has the same wire diameter. The coil portion is composed of two coil portions having different outer diameters. The inside of the angle portion has no small-diameter coil portion, and the inside of the flexible portion has no large-diameter coil portion. And the flexible part The connecting member connection location or the vicinity thereof is to its characterized in that a structure for coupling to rotate integrally.

Here, the difference between the outer diameter of the small-diameter coil portion and the inner diameter of the flexible tube is smaller than the deformation amount when the angle portion is in the maximum bending state and the flexible sleeve is flattened. In other words, it is desirable to set the outer diameter of the small-diameter coil portion to be smaller than the dimension in the short-axis direction when the angle portion is in the maximum bending state and the flexible sleeve is deformed to be flat. As an example of a movable member provided at the distal end of the insertion section in the endoscope, there is a movable lens of an objective lens group provided at the distal end hard portion. Aside from the case where the transfer coil rotates in one direction, the case where the transfer coil rotates in the forward and reverse directions, the transfer coil is wound in the opposite direction to each other.
It is desirable to use a heavy coil.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, an electronic endoscope using a solid-state imaging device is configured, and a part of an objective lens group forming an objective optical system of the electronic endoscope is moved in an optical axis direction. Although described below, the endoscope and the movable member provided at the distal end of the insertion portion thereof are not limited thereto.

FIG. 1 shows a schematic configuration of the entire endoscope. As is apparent from FIG. 1, the endoscope 1 is generally configured by connecting an insertion section 3 into a body cavity or the like to a main body operation section 2 and pulling out a universal cord 4 from the main body operation section 2. Things. The insertion section 3 connected to the main body operation section 2 is divided into a distal end hard section 3a, an angle section 3b, and a flexible section 3c in order from the distal end side in terms of function and structure.

The distal end hard portion 3a is made of a hard member,
As shown in FIG. 2, an illumination unit 10, an observation unit 11, a treatment tool lead-out unit 12, and a cleaning nozzle 13 are provided on the tip surface, and a jet water supply unit 14 is further opened. The angle portion 3b is configured to be able to bend in up, down, left, and right directions by an angle knob 5 provided on the main body operation portion 2 so as to turn the distal end hard portion 3a provided with the observation portion 11 and the like in a desired direction. I have. Furthermore, the flexible portion 3c occupies most of the length of the insertion portion 3, and the flexible portion 3c has a structure that is flexible in the bending direction and has crush resistance.
Therefore, it will bend in any direction along the insertion path.

FIG. 3 shows a cross section of a portion on the distal end side of the insertion portion 3. As is apparent from this figure, the distal end hard portion 3a has a main body block 20 made of, for example, a metal, and a through hole is formed in a required portion of the main body block 20 so as to penetrate in the axial direction. An insulating cap 21 is attached to the tip end surface of the main body block 20, and is fixed to the main body block 20 by a set screw 22. The angle portion 3b has a node ring structure in which a large number of angle rings 23 are sequentially pivoted by pivot pins 24. A metal net, fluorine rubber, EPD and the like are provided around the node ring structure composed of the angle rings 23.
A cover member 25 including an outer layer made of M, urethane rubber or the like is provided. Further, four operation wires 26 extend from the inside of the angle portion 3b toward the flexible portion 3c, and these operation wires 26 form a pair at the top and bottom and at the left and right, respectively. Pull one,
When the other is extended, the angle portion 3b is bent in the vertical direction. When one of the pair of left and right operation wires is pulled, and when the other is extended, the angle portion 3b is curved in the left and right direction.

The angle portion 3b is operated to bend up and down and left and right. The reason for bending the angle portion 3b in this way is to direct the hard distal end portion 3a in a desired direction. Accordingly, the distal end hard portion 3a can be directed in a desired direction in the insertion path where the insertion portion 3 is bent or branched. Further, when the insertion section 3 is arranged at a position in the body cavity where observation or diagnosis is performed, the angle section 3b is operated to bend when changing the direction of the observation visual field. The degree of bending at the time of the angle operation for changing the observation direction is, for example, a maximum bending angle of 18
It is bent at an extremely large bending angle, such as 0 ° or more. In addition, since the bending portion is bent to the maximum bending angle in a narrow body cavity, the length of the angle portion 3b is not much shorter than the entire length of the flexible portion 3c. You will bend.

The tip ring 23a located at the leading end of the multiple connected angle rings 23 constituting the angle portion 3b is connected to the main body block 20.
Therefore, in the insertion portion 3, the hard portion is a portion from the distal end surface of the insulating cap 21 to the position of the pivotal connection between the distal end ring 23a of the angle portion 3b and the other angle ring 23 pivotally connected thereto.

Observation section 11 provided at the tip of tip hard section 3a
Will be described with reference to FIG. 4 to FIG. First, in FIGS. 4 and 5, reference numeral 30 denotes a lens assembly constituting an objective optical system.
Is an observation unit mounting portion 11a provided on the main body block 20 (FIG. 3).
The objective lens system 30 includes an objective lens group 31. The optical path from the objective lens group 31 is 90 ° downward by the prism 32. It can be bent toward. The solid-state image sensor 33a joined to the prism 32 is located at the image forming position of the objective lens group 31.
Solid-state imaging device assembly 3 comprising a substrate and its substrate 33b
3 are arranged. In addition, a filter 34 having desired characteristics is provided between the objective lens group 31 and the prism 32, and an aperture (not shown) and the like are provided in addition to these.

A part (one or a plurality) of lenses 31a constituting the objective lens group 31 is a movable lens movable in the optical axis direction, and the remaining lens 31b is a fixed lens. The fixed lens 31b is fixedly mounted on a lens support frame 35 constituting a fixed lens frame, and the lens support frame 35 is joined to the surface of the prism 32. The movable lens 31a is mounted on the movable lens frame 36, and the movable lens frame 36 is slid along the inner surface of the lens support frame 35, so that the movable lens 31a is moved to the position shown in FIG. It will move in the optical axis direction between the positions shown. Therefore, the movable lens 31a is
Is a movable member provided at the tip of the.

As shown in FIG. 6, in order to make the optical axes of the movable lens 31a and the fixed lens 31b exactly coincide with each other,
The movable lens frame 36 provided with the movable lens 31a is movable in the optical axis direction in the lens support frame 35, and is fixedly held in other directions, that is, in a direction orthogonal to the optical axis and a tilting direction. I have. The movable lens frame 36 is provided with an arm portion 37 connected thereto. The arm portion 37 is provided on a lens support frame 35 with a slit 35 provided in the optical axis direction.
a to the outside through a nut 3
8 are connected in series. Here, the width dimension of the arm portion 37 substantially matches the groove width of the slit 35a, thereby restricting the movement of the movable lens frame 36 in the rotation direction.

With the above configuration, the movement of the movable lens frame 36 other than in the optical axis direction is almost completely restricted. The movable lens frame 36 moves in the optical axis direction by moving the nut portion 38 in a direction parallel to the optical axis along the screw axis 40. As described above, the movable lens 31a can be moved in the optical axis direction because of the observation depth, the imaging magnification,
This is for making at least one of the viewing angle and the like variable. Therefore, the movable lens 31a is a movable member provided at the tip of the insertion section 3.

The movable lens 31a is movable by remote control from the main body operation unit 2. For this purpose, a projection 35b is continuously provided on the lens support frame 35, and a shaft support member 39 formed in a substantially cylindrical shape is continuously provided on the projection 35b. The screw shaft 40 includes a screw rod portion 40a and a rotating shaft portion 40b. The rotating shaft portion 40b is rotatably and non-movably inserted into an insertion hole 39a formed in the shaft support member 39. The screw rod portion 40a projects a predetermined length forward from the shaft support member 39 by a predetermined length.
Reference numeral 8 is screwed into the projecting portion of the threaded rod portion 40a.

Reference numeral 41 denotes a control cable. The control cable 41 comprises a flexible sleeve 42 in which a transmission coil 43 is inserted. The distal end of the transmission coil 43 is connected to the screw shaft 40 by a connecting member 44. The connecting member 44 has a screw rod portion 4 that is screwed into the screw shaft 40 in a cylindrical body portion 44a into which the distal end portion of the transmission coil 43 is inserted and fixed by soldering, brazing, or the like.
4b, the screw rod portion 44b is screwed into the screw shaft 40 and fixed with an adhesive or the like. Therefore, the flexible end of the transmission coil 43 is the base end of the cylindrical body 44a. On the other hand, the distal end of the flexible sleeve 42 is inserted and fitted into a connection ring 45 screwed to the base end of the shaft support member 39, and is fixed by means of adhesion or the like. On the side, a fastening ring 46 is fitted and fixed by using an adhesive or the like. Accordingly, the flexible end of the flexible sleeve 42 is located at the base end of the connection ring 45 and the clamping ring 46. If the end positions of the connection ring 45 and the tightening ring 46 are different, the end position of the member located closer to the base end is changed to the flexible sleeve 4.
2 is the flexible end position.

When the proximal end of the transmission coil 43 is rotated around the axis in the flexible sleeve 42, the rotational force is applied to the screw shaft 4
0, the screw shaft 40 rotates, and the nut portion 38 and the movable lens frame 36 connected thereto move. In order to fix the screw shaft 40 so as not to move in the axial direction during this time, the outer diameter of the connecting member 44 is
The diameter of the hole 9a is larger than the diameter of the hole 9a. A flange 40c is formed on the rotary shaft 40b of the screw shaft 40, and the connecting member 44 and the flange 40c are in contact with the front and rear end faces of the insertion hole 39a.

The control cable 41 extends from the insertion section 3 into the main body operation section 2 and is connected to the rotation drive section. Therefore, FIGS. 7 and 8 show the configuration of this rotation drive unit. In the drawing, reference numeral 2a denotes a main plate of the main body operation unit 2, and a support member 50 is fixedly provided on the main plate 2a. The support member 50 is provided with a motor support unit 50a and a sleeve mounting unit 50b. Have been.

Motor support 50a of support member 50
Is fixedly provided with a motor 51 for rotationally driving the transmission coil 43 of the control cable 41. A rotating shaft 51a of the motor 51 is provided so as to be connected to a rotating cylinder 52. A hollow portion 52a having an open end is formed in the rotating cylinder 52 along the center axis of rotation. A slide piece 53 is axially movable by a predetermined stroke in the portion 52a, and is non-rotatably mounted. The slide piece 53 has a main body 53a that slides along the inner surface of the hollow portion 52a of the rotary cylinder 52. Detents 53b, 53b project from the main body 53a at two upper and lower positions. It is provided as follows. On the other hand, the rotary cylinder 52 has slits 52b, 5
2b are formed, and the rotation stopper 5 of the slide piece 53 is formed.
3b is projected from the slit 52b, so that the slide piece 53 rotates integrally with the rotary cylinder 52.

The slide piece 53 has a connecting portion 53c.
The transmission coil 43 of the flexible shaft 41 is bonded and brazed to the connecting portion 53c.
It is provided fixed by means such as a clamp. As a result, when the motor 51 is driven to rotate, the rotary cylinder 52 rotates integrally therewith. The rotation of the rotary cylinder 52 is transmitted to the slide piece 53, and the transmission coil 43 provided in connection with the slide piece 53 is provided. Is transmitted to the motor. In the drawing, reference numeral 54 denotes a stopper ring attached to the tip of the rotary cylinder 52.

The sleeve mounting portion 50b of the support member 50 is formed of a tapered cylindrical member whose outer diameter continuously decreases as it goes toward the distal end, and the transmission coil 43 passes through the inside thereof. ing. A ring-shaped wedge member 55 is fitted into the sleeve mounting portion 50b, and a screw ring 56 for driving the wedge member 55 is fitted.
Are screwed into the sleeve mounting portion 50b. Therefore, the proximal end of the flexible sleeve 42 is connected to the sleeve mounting portion 50b.
The wedge member 55 is fitted around the outer periphery of the sleeve mounting portion 50b.
By pushing in the direction to get on the tapered surface of
The distal end portion of the flexible sleeve 42 is clamped between the sleeve mounting portion 50b and the wedge member 55, so that the fixing can be performed.

When the movable lens 31a is disposed at the image forming side position shown in FIG. 4, the image forming magnification by the objective optical system is small and the viewing angle is wide. When the motor 51 is operated to rotate the transmission coil 43 of the control cable 41 around the axis in the flexible sleeve 42, the rotation is transmitted to the screw shaft 40, and the screw shaft 40 rotates. Therefore, the movable lens 31a is displaced to the subject side position shown in FIG. At this position, the imaging magnification by the objective optical system increases and the viewing angle decreases. In addition, the depth of focus of the movable lens 31a at each of these positions also changes, and the depth of focus becomes shallow at the position on the subject side. The position of FIG. 4 and the position of FIG. 5 may be set as the reciprocating stroke end positions, and the movable lens 31a may be stopped at an arbitrary position between them.

As described above, the transmission coil 43 of the control cable 41 connected to the screw shaft 40 for moving the movable lens 31a in the direction of the optical axis includes the flexible sleeve 4
In the state of being inserted into the main body operating portion 2, the rotary cylinder 52 is extended from the angle portion 3 b of the insertion portion 3 through the flexible portion 3 c into the main body operating portion 2 and connected to the motor 51 mounted on the main body operating portion 2. Are linked. Here, the transmission coil 43
Is composed of a metal wire wound in the form of a contact coil and rotates in forward and reverse directions.

As shown in FIG. 9, the transmission coil 43 has the same metal wire diameter as that of the transmission coil 43, but has a portion in the angle portion 3b and a portion in the flexible portion 3c. Have different coil diameters. Accordingly, a small-diameter coil portion 43a having a small coil diameter is formed from a connection portion to the connection member 44 connected to the screw shaft 40 to a position in the angle portion 3b. 3c is a large-diameter coil portion 43b having a large coil diameter. And these small diameter coil parts 4
3a and the large-diameter coil portion 43b are connected via a joint member 57 provided at a position of a connection portion between the angle portion 3b and the flexible portion 3c.

The joint 57 is provided with a large-diameter coil 43a.
The small-diameter coil portion 43b is connected to the small-diameter coil portion 43a so that the small-diameter rod portion 57a substantially coincides with the inner diameter of the small-diameter coil portion 43a. The connecting side to the coil portion 43b has a large-diameter rod portion 57b substantially matching the inner diameter of the large-diameter coil portion 43b, and the transition between the small-diameter rod portion 57a and the large-diameter rod portion 57b is a large-diameter coil. The flange portion 57c has a size not exceeding the outer diameter of the portion 43b. The small-diameter rod portion 57a is inserted into the base end of the small-diameter coil portion 43a, and the large-diameter rod portion 57b is inserted into the distal end of the large-diameter coil portion 43b. I am trying to do it.

Here, the transmission coil 43 is connected to the small-diameter coil section 4.
The connecting portion between 3a and the large-diameter coil portion 43b is hardened by the length of the joint portion 57. However, as is clear from FIG. 3, a connecting ring 58 is provided at the connecting portion between the angle portion 3b and the soft portion 3c, and the length H at which the connecting ring 58 is located is a hard portion. If the length of the joint portion 57 is set to a size that does not substantially protrude from the connection ring 58, even if the transmission coil 43 is hardened at this portion, the flexibility in the bending direction of the insertion portion 3 is particularly high. Has no effect.

The movable lens 31a is moved in the optical axis direction not only when the angle portion 3b is straight, but also when the angle portion 3b is curved. Therefore, at this time, the transmission coil 43
Will slide with the inner surface of the flexible sleeve 42. Therefore, the sliding resistance is minimized by making at least the inner surface of the flexible sleeve 42 slippery.
Even so, if the transmission coil 43 is strongly pressed against the flexible sleeve 42, the sliding resistance increases, and rotation transmission unevenness may occur, or in extreme cases, the lock state may be established. When the flexible sleeve 42 is sharply bent, the flexible sleeve 42 is deformed so as to be in a flat state against its shape retention.
In particular, when the angle portion 3b is bent to the maximum bending angle, the flexible sleeve 42 is most greatly deformed. Here, in the case where the degree of flattening is reduced by giving the flexible sleeve 42 a rigidity that does not easily bend, the bending rigidity of the entire insertion portion 3 increases, and the insertability deteriorates. Such inconveniences occur.

From the above, as shown in FIG.
In a state where no bending force is applied to the flexible sleeve 42, the flexible sleeve 42 is held in a circular shape as shown by a virtual line, and when the angle portion 3b is bent to the maximum bending angle, as shown by a solid line in FIG. As a result, even if the flattened state is attained, a space is secured so that the movement of the transfer coil 43 in the flexible sleeve 42 is not restricted as much as possible. Therefore, transmitting the D ₁ of the FIG. 10 coil 43
Dimension greater outer diameter, when the length of the short axis at the time when the most flattened flexible sleeve 42 to D _2, the same or a D ₂ and D _1, or towards the D ₂ of the small-diameter coil portion 43a of the And As a result, even if the angle portion 3b is bent to the maximum bending angle state, a space is provided in which the transfer coil 43 can still move within the cross section of the flexible sleeve 42. In other words, no matter how the flexible sleeve 42 is flattened,
A sufficient diameter difference is provided between the inner diameter of the flexible sleeve 42 and the outer diameter of the transmission coil 43 so as to secure a space at least as large as the outer diameter of the transmission coil 43. It is for this reason that the portion of the transmission coil 43 located in the angle portion 3b is the small-diameter coil portion 43a. Therefore, as the outer diameter of the small-diameter coil portion 43a is reduced, the transmission coil 43 can be smoothly rotated with a light load even in a state where the angle portion 3b is curved.

By the way, if the diameter difference between the flexible sleeve 42 and the transmission coil 43 is too large, when the insertion portion 3 bends along the insertion path, the transmission coil 43 moves in the axial direction of the flexible sleeve 42. Will move. here,
The base end of the transmission coil 43 is derived from the end of the flexible sleeve 42 by a predetermined length and is connected to the motor 51 as a driving unit, so that the derived length of the transmission coil 43 varies. . Then, in order to absorb the variation of the lead-out length, the flexible sleeve 42 is connected to the sleeve mounting portion 50 of the support member 50 on the base end side of the control cable 41.
b and the transfer coil 43 is
, The slide piece 53 is movable in the axial direction with respect to the rotary cylinder 52, and is connected so as to rotate integrally. The slide piece 53 can be reciprocated by the stroke S shown in FIG. However, if the amount of movement of the transmission coil 43 exceeds this stroke S, the transmission coil 43 will meander in the flexible sleeve 43, and will hinder smooth transmission of rotation.

By the way, even if the flexible portion 3c bends along the insertion path, the bend is gradual.
Since there is no possibility that the flexible sleeve 42 is deformed so as to be flattened in the inside, it is not necessary to make the diameter difference between the outer diameter of the transfer coil 43 and the inner diameter of the flexible sleeve 43 too large. For this reason, the flexible portion 3c of the transmission coil 43
The portion located inside the inside is a large-diameter coil portion 43b to minimize the difference in diameter from the inner diameter of the flexible sleeve 42. Since the length of the flexible portion 3c is much longer than that of the angle portion 3b, reducing the diameter difference between the transmission coil 43 and the flexible sleeve 42 at this portion reduces the insertion portion 3c. Of the transfer coil 43 from the flexible sleeve 42 when the is bent.

Accordingly, the movable stroke range S of the slide piece 53 for absorbing the fluctuation width of the length of the transfer coil 43 with respect to the flexible sleeve 42 can be minimized. As a result, the total length of the connection mechanism of the control cable 41 to the motor 51 as the drive unit can be reduced, and the drive unit can be reduced in size, size, and weight.

In the above-described embodiment, the transmission coil constituting the control cable is configured to be driven by the motor. However, the transmission coil may be configured to be driven by a manual operation or the like. The mechanism for absorbing the movement of the transmission coil is not limited to those shown in FIGS.

[0043]

According to the present invention, the sliding resistance between the transmission coil and the flexible sleeve is minimized when the movable member provided at the tip of the insertion portion is driven. In addition, the variation in the length of the lead-out of the transfer coil from the flexible sleeve due to bending can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an endoscope showing one embodiment of the present invention.

FIG. 2 is an external view showing a distal end surface of an insertion portion of the endoscope in FIG. 1;

FIG. 3 is a longitudinal sectional view of the vicinity of a distal end of an insertion portion.

FIG. 4 is a longitudinal sectional view showing a driving mechanism of a movable lens of an observation unit.

FIG. 5 is a sectional view similar to FIG. 4, showing a state in which the movable lens is advanced.

FIG. 6 is an exploded perspective view of the lens assembly.

FIG. 7 is a plan view of a movable lens driving unit provided in the main body operation unit.

8 is a longitudinal sectional view of FIG.

FIG. 9 is a sectional view of a transmission coil.

FIG. 10 is a sectional view showing a state of the control cable when the angle portion is bent.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Endoscope 2 Main body operation part 3 Insertion part 3a Hard tip part 3b Angle part 11 Observation part 30 Lens assembly 31 Objective lens group 31a Movable lens 36 Movable lens frame 41 Control cable 42 Flexible sleeve 43 Transmission coil 43a Small diameter coil part 43b Large-diameter coil part 50 Support member 50a Motor support part 50b Sleeve mounting part 51 Motor 52 Rotating cylinder 52b Slit 53 Slide piece 54 Stopper ring 57 Joint part

Claims (4)

[Claims] 1. A movable member mounted on a distal end of an insertion portion connected in order of a distal end hard portion, an angle portion, and a soft portion from a distal end side from a main body operation portion connected to a base end portion of the insertion portion. In order to drive, a metal wire is spirally wound, one end is connected to the movable member, and the other end is connected to a rotary drive unit, and the transfer coil is inserted, and both ends are fixed. In the control cable for an endoscope comprising: a flexible sleeve, the transmission coil is formed of two coil portions having substantially the same wire diameter and different outer diameters; A small-diameter coil portion having a small outer diameter is not provided.A large-diameter coil portion having a large outer diameter is provided within the flexible portion. Both of these coil portions are integrated by a connecting member at or near a connection position between the angle portion and the flexible portion. rotation Endoscopic control cable, characterized in that it has a configuration that connects to so that. 2. An outer diameter of the small-diameter coil portion is set to be smaller than a dimension in a short-axis direction when the angle portion is in a maximum curved state and the flexible sleeve is deformed so as to be flattened. The control cable for an endoscope according to claim 1, wherein 3. The control cable for an endoscope according to claim 1, wherein the movable member is a movable lens of an objective lens group provided at the distal end hard portion. 4. The transmission coil comprises a contact coil,
2. The control cable for an endoscope according to claim 1, wherein said contact coil is constituted by a double coil wound in mutually opposite directions.