JP2002000552A - Flexible tube for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible tube for endoscope which is excellent in operability for insertion by specifying the flexibility changing rate of the tube in the longitudinal direction. SOLUTION: The flexibility changing rate B ( X, Y}= W(X)-W(Y)}/W(Y)) of this flexible tube 1 provided in the inserting section of an endoscope meets the relations of 0.2<=B L/3, 0)<=1.5, 0<=B 2L/3, L/3)<=0.4, and 0<=B L, 2L/3)<=0.5 when the length of the tube 1 between front-side and base-side datum points 13 and 14 which are respectively positioned 125 mm inward from both ends of the tube 1 is L mm and the magnitudes of pressing forces when a measuring spot at X mm and Y mm base-side end side from the front-side datum point 13 is displaced by 50 mm in the pressing direction by pressing the measuring spot while the tube 1 is supported by two knife edges separated from each other by a span of 200 mm so that the measuring spot may become the center of the span are W(X) and W(Y), respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube for an endoscope.

[0002]

2. Description of the Related Art An insertion portion of a medical endoscope into a body cavity is provided inside a tubular member by, for example, an optical fiber, an electric cable,
Cables, tubes, and the like are arranged and inserted. Most of the entire length of the tubular member is constituted by a flexible (elastic) endoscope flexible tube, and a distal end thereof is connected to a curved portion as a foremost portion. The bending portion can be operated in the bending direction from the operation portion via a wire disposed inside the flexible tube for an endoscope.

In endoscopy, an endoscope is inserted deep into a body cavity such as the stomach, duodenum, small intestine or large intestine. At this time, since the flexible tube for an endoscope is inserted along a bent body cavity, the operability of the insertion largely depends on the flexibility of the flexible tube for an endoscope.

More specifically, when the distal end to the proximal end of the flexible tube for an endoscope is roughly divided into a distal end portion, an intermediate portion, and a proximal portion, the distal end portion has a curved portion in a deep part of the body. One that is sufficiently soft has good insertion operability so that it can smoothly advance following a steep lumen. Also, the wrist is easy to apply pushing force and torsion (rotation),
Preferably, the stiffness is relatively high. In addition, the intermediate portion ensures that the pushing force and rotation applied at the proximal portion are transmitted to the distal portion, and that the patient does not feel pain, so the intermediate portion between the distal portion and the proximal portion is used. It is preferable to have appropriate rigidity.

In view of the above, conventionally, for the purpose of improving the operability of insertion, a flexible endoscope having a structure in which the flexibility changes along the longitudinal direction of the flexible tube for an endoscope has been used. There was a tube. Such flexible tubes for endoscopes have a configuration in which the rigidity increases stepwise from the distal end to the proximal end, or have a substantially constant ratio (ratio) from the distal end to the proximal end. In some cases, the rigidity is increased.

However, the manner of changing the flexibility of the flexible tube for an endoscope along the longitudinal direction has not been optimized from the viewpoint of the operability of insertion. For this reason, for example, when the tip portion has high flexibility, the middle portion becomes too soft, and the pushing force and torsion from the hand portion are not reliably transmitted to the tip portion (the pushing property and the torque transmitting property are not good). ). On the other hand, when the intermediate portion has sufficient rigidity, the rigidity of the distal end portion is too strong and the distal end portion cannot bend to a sufficiently small radius of curvature along a curved lumen. .

That is, in the conventional flexible tube for an endoscope, the flexibility of each part is not balanced, so that the overall operability of insertion has not been satisfactory. . For this reason, not only is the examination time prolonged because the insertion operation is time-consuming, but also there is an adverse effect that the burden and pain on the patient increases.

[0008]

SUMMARY OF THE INVENTION The present invention defines a degree of change in flexibility along a longitudinal direction, and an object of the present invention is to provide a flexible tube for an endoscope having excellent insertion operability. Is to provide.

[0009]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) A flexible tube for an endoscope, wherein a position at a distance of 125 mm from a distal end of the flexible tube for an endoscope in a proximal direction is defined as a distal-side reference point, When a position at a distance of 125 mm in the distal direction from the proximal end of the flexible tube is defined as a proximal-side reference point, and the length between the distal-side reference point and the proximal-side reference point is defined as Lmm, the following equation is used. The flexibility change rate B {X, Y} determined by (I) is represented by the following equation: B {X, Y} = {W (X) −W (Y)} / W (Y) (I) In the formula, W (X) and W (Y) are measured at a position at a distance of X mm and Y mm from the distal-side reference point in the base end direction, respectively. Supporting the flexible tube for the endoscope so as to be the center of the span, pressing the measurement location, the measurement location is in the pressing direction. It represents the magnitude of the pressing force when displaced by 50 mm.) 0.2 ≦ B {L / 3, 0} ≦ 1.5, 0 ≦ B {2L / 3, L / 3} ≦ 0.4, and , 0 ≦ B
A flexible tube for an endoscope, which satisfies the relationship of {L, 2L / 3} ≦ 0.5.
Thus, a flexible tube for an endoscope having excellent insertion operability can be provided.

(2) The rate of change in flexibility B {X, Y}
B 、 L / 3,0｝> B ｛L, 2L / 3｝> B ｛2L /
3. The flexible tube for an endoscope according to the above (1), which satisfies a relationship of 3, L / 3｝. Thereby, the operability of the insertion is further improved.

(3) The flexibility change rate B {X, Y}
Is 0.2 ≦ (5 / m) · B {mL / 15,0} ≦ 1.5, 0 ≦ (5 / m) · B} (m) m + 5) · L / 15, L / 3｝
≦ 0.4 and 0 ≦ (5 / m) · B ｛(m + 10)
The flexible tube for an endoscope according to the above (1) or (2), which satisfies the following relationship: L / 15, 2L / 3 ／ ≦ 0.5. Thereby, the operability of the insertion is further improved.

(4) The rate of change in flexibility B {X, Y}
Is any one of the above (1) to (3) that satisfies the relationship of B {(nL / 15 + L / 15), (nL / 15)} ≧ 0 for all n that are integers from 0 to 14. 4. The flexible tube for an endoscope according to claim 1. Thereby, the operability of the insertion is further improved.

(5) The method according to any one of the above (1) to (4), wherein the magnitude W (0) of the pressing force with the reference point on the tip side as a measurement point is 1.0 to 9 N. Flexible tube for endoscope.

[0015] Thereby, the followability of the distal end portion to the body cavity is improved, and the operability of insertion is further improved.

(6) The endoscope according to any one of the above (1) to (5), comprising a tubular core material and a single-layer or multi-layer laminated outer skin coated on the outer periphery of the core material. Flexible tube. Thereby, sufficient mechanical strength can be secured.

(7) The flexibility is changed along the longitudinal direction by changing the thickness and / or the constituent material of at least one of the layers constituting the outer skin along the longitudinal direction. The flexible tube for an endoscope according to the above (6). Thereby, a suitable flexibility change rate can be easily obtained.

(8) The outer shell has a portion composed of a laminate having an inner layer, an outer layer, and at least one intermediate layer located therebetween.
Or the flexible tube for endoscopes according to (7).

As a result, various performances required for the flexible tube for an endoscope can be improved, and a suitable rate of change in flexibility can be obtained.

(9) The flexible tube for an endoscope according to any one of the above (6) to (8), wherein the outer cover is formed by coating an outer periphery of the core material by extrusion. Thereby, a flexible tube for an endoscope can be manufactured with good productivity and preferably.

(10) The core material includes a spiral tube formed by spirally winding a belt-shaped material, and a braided body that is formed by braiding a thin wire, which is coated on the outer periphery of the spiral tube and braided. The flexible tube for an endoscope according to any one of (6) to (9). Thereby, sufficient mechanical strength can be secured.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a flexible tube for an endoscope according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an overall view showing an electronic endoscope (electronic scope) having an insertion portion flexible tube to which the flexible tube for an endoscope of the present invention is applied. Hereinafter, in FIG. 1, the upper side will be described as a “base end” and the lower side as a “distal end”.

As shown in FIG. 1, the electronic endoscope 10 includes a flexible insertion tube 1 having a long elasticity and a curved portion 5 connected to a distal end 11 of the insertion flexible tube 1. , Insertion part flexible tube 1
Provided at the base end 12 of the electronic endoscope 10
It comprises an operation unit 6 for operating the whole, a connecting portion flexible tube 7 connected to the operating portion 6, and a light source insertion portion 8 provided on the distal end side of the connecting portion flexible tube 7.

The flexible insertion tube 1 is used by being inserted into a lumen of a living body. The operation unit 6 is provided with operation knobs 61 and 62 on its side surface. These operation knobs 61 and 6
2, the wire (not shown) disposed in the insertion section flexible tube 1 is pulled, and the distal end 1 of the insertion section flexible tube 1 is pulled.
The bending portion 5 connected to 1 is bent in four directions, and the bending direction can be freely changed.

An image pickup device (CCD) (not shown) for picking up an image of a subject at an observation site is provided at the distal end of the bending section 5, and an image signal connector 82 is provided at the distal end of the light source insertion section 8. Have been. The image signal connector 82 is connected to a light source processor (not shown),
Further, the light source processor device is connected to a monitor device (not shown) via a cable.

A light source connector 81 is provided at the tip of the light source insertion portion 8, and the light source connector 81 is connected to a light source processor. The light emitted from the light source in the light source processor device is connected to the light source connector 81, the light source insertion portion 8, the connection portion flexible tube 7, the operation portion 6,
The light passes through a light guide (not shown) composed of an optical fiber bundle continuously disposed in the insertion portion flexible tube 1 and the bending portion 5, and is irradiated from the distal end portion of the bending portion 5 onto the observation site to be illuminated.

The reflected light (subject image) from the observation site illuminated by the illumination light is picked up by an image pickup device. An image signal corresponding to the subject image picked up by the image pickup device is output via a buffer (not shown).

This image signal is continuously arranged in the bending section 5, the insertion section flexible tube 1, the operation section 6 and the connection section flexible tube 7, and the image sensor and the image signal connector 82 Is transmitted to the light source insertion unit 8 via an image signal cable (not shown) for connecting.

Then, predetermined processing (for example, signal processing, image processing, and the like) is performed in the light source insertion unit 8 and the light source processor, and then input to the monitor. In the monitor device, an image (electronic image) captured by the image sensor,
That is, an endoscope monitor image of a moving image is displayed.

The overall configuration of the electronic endoscope 10 having the flexible insertion tube 1 to which the flexible tube for an endoscope of the present invention is applied has been described above. Needless to say, the present invention can be applied to a flexible tube of a fiber endoscope.

FIG. 2 is a view showing the entire appearance of an insertion portion flexible tube to which the flexible tube for an endoscope of the present invention is applied, and FIG. 3 is a diagram for measuring the flexibility of the flexible tube for an endoscope. FIG. 4 is a diagram showing a method for performing the operation. In the following description, the left side (the distal end 11 side of the insertion section flexible tube 1) in FIG. 2 is “front”, and the right side (the insertion section flexible tube 1) in FIG.
Is referred to as “rear”.

The flexible tube 1 shown in FIG. 2 has a flexibility (elasticity) that changes along the longitudinal direction. The term “flexibility” as used herein refers to the flexibility of the insertion section flexible tube 1 alone, excluding optical fibers, cables, tubes, and the like that are inserted into the insertion section flexible tube 1 when assembled as an endoscope. Say gender.

The flexibility of the flexible tube for an endoscope generally corresponds to that shown in FIG.
Can be measured by the method shown in FIG. The method for measuring the flexibility will be described below.

First, the insertion portion flexible tube 1 is straightened in a state where no external force acts (natural state), and two knife edges 90 (support points) having a span of a predetermined distance (length indicated by S in FIG. 3). ). At this time, the flexible measurement point is located at the center (center) of the span. Next, from the side opposite to the side where the knife edge 90 is in contact,
The measurement location is pressed in a direction perpendicular to the longitudinal direction (arrow W in FIG. 3). The pressing force causes the insertion portion flexible tube 1
Is deflected, and the measuring point is the direction in which the pressing force acts (pressing direction)
Then, the magnitude of the pressing force W when displacing a predetermined distance (the length indicated by T in FIG. 3) is measured.

If the magnitude of the pressing force W required to displace the measurement location by a certain distance T is large, the flexibility of the location is small (high rigidity). Conversely, if the pressing force W is small, It can be said that the flexibility of the portion is large (high elasticity).

Here, the span of the knife edge 90 is set to 2
The flexibility is measured based on the magnitude of the pressing force W when the measurement location is displaced by 50 mm. The magnitude of the pressing force W measured under such conditions is hereinafter referred to as “bending stiffness” of the measurement location.

At the time of measurement, the knife edge 90 and the flexible tube 1 are not fixed. For this reason, in a state where the insertion portion flexible tube 1 is bent by pressing the measurement portion, the length of the insertion portion flexible tube 1 located between the spans may be longer than 200 mm.

The bending stiffness of the flexible insertion tube 1 measured as described above changes along the longitudinal direction. The state of the change will be described below.

However, in the above-described flexibility measuring method, the flexibility near both ends of the flexible tube 1 cannot be measured. Therefore, in order to exclude portions near both ends where the flexibility cannot be measured, the concept of reference points 13 and 14 located inside a predetermined distance from both ends of the insertion portion flexible tube 1 will be introduced below. The change in flexibility between points will be described.

As shown in FIG. 2, a position at a distance of 125 mm from the distal end 11 to the proximal end 12 of the flexible tube 1 is defined as a distal-side reference point 13, and 125 mm from the proximal end 12 to the distal end 11. The position at the distance of is referred to as the base end reference point 14. Between the distal-side reference point 13 and the proximal-side reference point 14, the insertion portion flexible tube 1
(Flexural rigidity) can be measured.

The reference point 13 on the distal side and the reference point 1 on the proximal side
4 is L mm. That is, the total length of the flexible tube 1 is (L + 250) mm. Hereinafter, a position at a distance of X mm from the distal-side reference point 13 in the direction of the base end 12 is referred to as a “X mm position”. According to this, for example, the distal-side reference point 13 is a “0 mm position”, and the proximal-side reference point 14 is a “L mm position”.

The change in flexibility along the longitudinal direction of the flexible tube 1 of the insertion portion is represented by a flexibility change rate B {X, Y} determined by the following equation (I). B {X, Y} = {W (X) -W (Y)} / W (Y) (I)

In the formula (I), W (X) and W (Y) are
With the position of X mm and the position of Y mm as measurement points, respectively, the magnitude of the pressing force W when the flexibility is measured by the above-described method is shown. That is, W (X) and W
(Y) represents the bending stiffness at the position of Xmm and the position of Ymm, respectively.

According to the flexibility change rate B {X, Y}, Ym
The increase ratio of the bending stiffness at the position of X mm to the bending stiffness at the position of m is expressed. For example, if B {X, Y} = 0, the bending stiffness at the position of Xmm is the same as the bending stiffness at the position of Ymm, and if B {X, Y} = 1, the bending stiffness at the position of Xmm The rigidity is twice the bending rigidity at the position of Ymm.

In the following, the flexible tube 1 of the insertion portion is divided into a distal end portion 15, an intermediate portion 16, and a hand portion 17, and the change in the flexibility of each of these portions along the longitudinal direction is represented by a flexibility change rate B ｛X , Y}. Here, the tip portion 15 is a portion from the tip 11 to a position of (L / 3) mm, and the intermediate portion 16 is
The portion from the position (L / 3) mm to the position (2L / 3) mm, and the hand portion 17 is the portion from the position (2L / 3) mm to the base end 12.

The ratio (ratio) of the change in flexibility when the tip 15 is viewed as a whole is represented by the rate of change in flexibility B {L / 3, 0}. The insertion portion flexible tube 1 has a flexibility change rate B ｛L /
The value of 3,0｝ is 0.2 or more and 1.5 or less.
This means that the bending stiffness at the position of (L / 3) mm is 2 with respect to the bending stiffness at the position of 0 mm, that is, the bending point at the tip side reference point 13.
It means that it increases by 0 to 150% (increases by 1.2 to 2.5 times). Also, B {L / 3,0}
Is more preferably 0.3 or more and 1.4 or less.

In the distal end portion 15, the ratio of the change in flexibility (the ratio of the change in bending stiffness) is relatively large. Therefore, (L /
3) The bending rigidity is sufficiently reduced from the position of mm toward the tip 11. Therefore, the distal end portion 15 has sufficiently high flexibility. Thereby, the tip 15
Can bend to a sufficiently small radius of curvature along a deeply curved lumen in the body. For this reason, the tip 15
It has good followability when advancing deep into a body cavity, and is particularly excellent in operability when inserting it into the deepest part such as the large intestine. In addition, since the distal end portion 15 has high flexibility, the body is hardly damaged and the safety is excellent.

The bending stiffness of the reference point 13 on the tip side, that is,
W (0) is not particularly limited, but is preferably from 1.0 to 9N, more preferably from 2 to 8N in the case of a medical endoscope. Thereby, the followability of the distal end portion 15 to the body cavity is improved, and the operability and safety of insertion are further improved.

When the value of the flexibility change rate B {L / 3,0} is 0.
If it is smaller than 2, the flexibility of the distal end portion 15 and the pushability and torque transmission cannot be compatible.

If the value of the rate of change in flexibility B {L / 3, 0} is larger than 1.5, the bending stiffness at the position of (L / 3) mm becomes too high, and the followability to the lumen becomes poor. Getting worse. Further, the burden and distress on the patient also increases.

The ratio (ratio) of the change in flexibility when the intermediate portion 16 is viewed as a whole is as follows: the rate of change in flexibility B ｛2L / 3, L /
It is represented by 3｝. The insertion portion flexible tube 1 has a flexibility change rate B
The value of {2L / 3, L / 3} is 0 or more and 0.4 or less. This is because the bending stiffness at the position (2L / 3) mm is 0 to 40% with respect to the bending stiffness at the position (L / 3) mm.
It means that it increases (becomes 1 to 1.4 times). The value of B {2L / 3, L / 3} is
More preferably, it is 0.05 or more and 0.3 or less.

In the intermediate portion 16, the ratio of the change in the flexibility (the ratio of the change in the bending rigidity) is relatively small. Further, since the rate of change in the flexibility of the distal end portion 15 is relatively large, the distal end portion 15 is generally flexible as described above, but the bending rigidity at the position of (L / 3) mm is moderate. It has become something. Therefore, the intermediate part 1
No. 6 has a moderate rate of change in bending stiffness (ratio), and has moderate bending stiffness of a medium size over the entire length.

With such a configuration, the intermediate portion 16 has sufficient bending rigidity to reliably transmit the pushing force and the torsion (rotation) applied to the proximal portion 17 to the distal end portion 15 over its entire length. Across, it is prepared. Thereby, the insertion portion flexible tube 1 is excellent in pushability and torque transmission.

Further, since the intermediate portion 16 has a moderate bending rigidity and a moderate size, it does not strongly press the wall of the body cavity, so that the burden and pain on the patient can be reduced. .

Since the intermediate portion 16 has a relatively small change rate (ratio) in bending rigidity, the force applied from the hand portion 17, such as pushing force or twisting, is applied to the tip portion 15 in a natural manner. Is transmitted. Therefore, the distal end portion 15 does not move unexpectedly of the operator, and the operator can operate the distal end portion 15 as desired, and an excellent operational feeling can be obtained.
Furthermore, since the bending rigidity does not become too high even in the portion close to the hand portion 17, the burden and pain on the patient does not increase.

If the value of the rate of change in flexibility B {2L / 3, L / 3} is smaller than 0, a portion where the bending rigidity is too small occurs in the intermediate portion 16. As a result, the intermediate portion 16 bends even smaller than the radius of curvature necessary to follow the curvature of the body cavity (formation of a loop), and the pushing force from the hand portion 17 is hardly transmitted to the distal end portion 15 (buckling). State).

The rate of change in flexibility B 可 撓 2L / 3, L /
If the value of 3｝ is larger than 0.4, the bending rigidity becomes too high, particularly in the portion close to the hand portion 17, so that the flexibility becomes extremely small, and the burden and pain on the patient increase. It becomes difficult to use it as a flexible tube for an endoscope.

The ratio (ratio) of the change in flexibility when the hand portion 17 is viewed as a whole is represented by the change ratio B {L, 2L / 3}.
It is represented by The insertion portion flexible tube 1 has a flexibility change rate B ｛L,
The value of 2L / 3｝ is 0 or more and 0.5 or less. This is because the bending stiffness at the position of (2L / 3) mm is L
mm, that is, the bending rigidity of the base-side reference point 14 is 0.
５０50% increase (1 to 1.5 times). The value of B {L, 2L / 3} is more preferably 0.1 or more and 0.4 or less.

In the hand portion 17, the ratio of the change in flexibility (the ratio of the change in bending stiffness) is a medium size. Thereby, the bending rigidity increases at an appropriate rate from the medium bending rigidity at the position of (2L / 3) mm, which is the boundary between the intermediate portion 16 and the hand portion 17, toward the base end 12. Therefore, since the hand portion 17 has a relatively high and sufficient rigidity particularly in the latter half thereof, it is easy to apply an operating force such as a pushing force or a twisting force. Further, the pushing force and torsion applied to the hand portion 17 can be efficiently transmitted to the intermediate portion 16.

The value of the flexibility change rate B {L, 2L / 3} is 0
If it is smaller, the bending stiffness of the hand portion 17, especially in the latter half, is insufficient, and it is difficult to apply an operating force.

If the value of the rate of change in flexibility B {L, 2L / 3} is larger than 0.5, the bending rigidity of the hand portion 17 becomes too large, and the flexibility becomes extremely small. In addition, it becomes difficult to use the flexible tube for an endoscope.

The ratio (ratio) of the overall change in the flexibility of the distal end portion 15, the intermediate portion 16, and the proximal portion 17 as described above is B 、 L / 3, 0｝> B ｛L. , 2L / 3｝> B ｛2L /
It is preferable to satisfy the relationship of 3, L / 3 ／. This is because the ratio (ratio) of the general flexibility change in each part of the flexible tube 1 is
The largest at the tip 15, then at the hand 16,
It means that it is the smallest in the middle part 16. This allows
The balance between each of the distal end portion 15, the intermediate portion 16, and the hand portion 17 is more excellent, and the above-described effect is more significantly exerted.

Further, in the tip portion 15, the flexibility change rate B {X, Y} is 0.2 ≦ 5 · B {L / 15,0} ≦ 1.5, 0.2 ≦ (5/2 ) · B {2L / 15,0} ≦ 1.5, 0.2 ≦ (5/3) · B {L / 5,0} ≦ 1.5 and 0.2 ≦ (5/4). B {4L / 15,0} ≦ 1.
It is preferable to satisfy the following relationship:

That is, the rate of change in flexibility B {X, Y} is
It is preferable that the relationship of 0.2 ≦ (5 / m) · B {mL / 15,0} ≦ 1.5 is satisfied for all m that is an integer of 1 to 4.

These relations are determined by comparing the reference point 13 on the distal side with (L
/ 3) Each point that divides the distance from the position of mm into 5 equal parts, that is,
(L / 15) mm position, (2L / 15) mm position,
The ratio (ratio) of the change in flexibility between the position of (L / 5) mm and the position of (4L / 15) mm and the tip-side reference point 13 is the change in flexibility of the entire tip portion 15, respectively. Means the same as (ratio). This allows
The change in the flexibility of the distal end portion 15 becomes smooth, and the above-described effect is more exerted.

Similarly, in the intermediate portion 16, the rate of change in flexibility B {X, Y} is 0 ≦ 5 · B {2L / 5, L / 3} ≦ 0.4, 0 ≦ (5/2 ) · B {7L / 15, L / 3} ≦ 0.4, 0 ≦ (5/3) · B {8L / 15, L / 3} ≦ 0.4,
And 0 ≦ (5/4) · B {3L / 5, L / 3} ≦
0.4, is preferably satisfied.

That is, the rate of change in flexibility B {X, Y} is
0 ≦ (5 / m) · B {(m + 5) · L / 15, L / 3} for all m that are integers from 1 to 4.
It is preferable to satisfy the relationship of ≦ 0.4.

These relations are as follows: each point dividing the intermediate portion 16 into five equal parts, that is, a position of (2L / 5) mm, (7L / 1
5) mm position, (8L / 15) mm position and (3
The ratio (ratio) of the change in flexibility between the position of (L / 5) mm and the position of (L / 3) mm is the same as the ratio (ratio) of the change in flexibility of the entire intermediate portion 16. It means to be about. Thereby, the change in the flexibility of the intermediate portion 16 becomes smooth, and the above-described effect is more exerted.

Similarly, in the hand portion 17, the flexibility change rate B {X, Y} is 0 ≦ 5 · B {11L / 15, 2L / 3} ≦ 0.5, 0 ≦ (5 / 2) · B {4L / 5, 2L / 3} ≦ 0.5, 0 ≦ (5/3) · B {13L / 15, 2L / 3} ≦ 0.
5 and 0 ≦ (5/4) · B ｛14L / 15,2L
It is preferable that the following relationship be satisfied.

That is, the rate of change in flexibility B {X, Y} is
0 ≦ (5 / m) · B ｛(m + 10) · L / 15, 2L /
It is preferable to satisfy the relationship of 3｝ ≦ 0.5.

These relations are as follows: each point which divides the distance between the position of (2L / 3) mm and the base end reference point 14 into five equal parts, ie, the position of (11L / 15) mm, (4L / 5) mm position, (13L / 15) mm position and (14L / 1
5) The ratio (ratio) of the change in flexibility between the position of mm and the position of (2L / 3) mm is approximately the same as the ratio (ratio) of the change in flexibility of the entire wrist portion 17, respectively. It means becoming. Thereby, the change in the flexibility of the hand portion 17 becomes smooth, and the above-described effect is more significantly exerted.

Further, it is preferable that the flexible tube 1 of the insertion portion has a higher bending rigidity as the distance from the distal end 11 to the proximal end 12 increases (however, a portion having a constant bending rigidity may be provided). . Such a change in the bending stiffness is such that the bending stiffness of each point that divides the distance between the distal-side reference point 13 and the proximal-side reference point 15 into 15 equal parts is W (0) ≦ W (L / 15) ≦ W ( 2L / 15) ≦ W (L
/5)≤.........≤W(4L/5)≤W(13L/1
5) ≦ W (14L / 15) ≦ W (L) By satisfying the relationship:

That is, when expressed by the rate of change in flexibility B {X, Y}, for all n which are integers from 0 to 14, B {(nL / 15 + L / 15), (nL / 15)} It is preferable to satisfy the relationship of ≧ 0.

As a result, the pushability and the torque transmission are further improved. In addition, the balance between the distal end portion 15, the intermediate portion 16, and the proximal portion 17 is more excellent.

The insertion section flexible tube 1 may be of any configuration as long as it satisfies the above-described flexibility change rate. For example, the insertion section flexible tube 1 may be configured as described below. The flexibility change rate as described is obtained.

FIG. 4 is a longitudinal sectional view showing an embodiment of the flexible tube 1 of the insertion portion. 4, the right side is the base end 12 side (hand side) and the left side is the front end 11 side.

As shown in FIG. 4, the flexible tube 1 has a core material 2 and an outer cover 3 covering the outer periphery thereof. In addition, the insertion portion flexible tube 1 has a space 23 in which instruments (not shown) such as an optical fiber, an electric cable, a cable or a tube can be arranged and inserted.
Is provided.

The core member 2 is composed of a spiral tube 21 and a braided tube (braided body) 22 that covers the outer periphery of the spiral tube 21, and is formed as a tube-like long object as a whole. The core material 2 has an effect of reinforcing the insertion portion flexible tube 1. In particular, by combining the spiral tube 21 and the mesh tube 22,
The insertion portion flexible tube 1 can ensure sufficient mechanical strength. Although not shown, the core material 2 is composed of a double spiral tube 21,
Alternatively, by providing three layers, higher mechanical strength can be obtained.

The spiral tube 21 is formed by spirally winding a belt-like material with a uniform diameter at intervals. As a material constituting the belt-like material, for example, stainless steel, a copper alloy, or the like is preferably used.

The mesh tube 22 is formed by braiding a plurality of thin lines made of metal or non-metal. As a material constituting the fine wire, for example, stainless steel, a copper alloy, or the like is preferably used.

The outer periphery of the core material 2 is covered with an outer skin 3. The outer cover 3 is formed of a laminate having an inner layer 31, an outer layer 32, and an intermediate layer 33.

The inner layer 31 is formed on the innermost side of the outer skin 3 and is in close contact with the core material 2.

The inner layer 31 has an adhesive property (coupling force) with the core material 2.
It is preferable to be composed of a material having a high Thereby, the outer skin 3 is securely fixed to the core material 2. Therefore, the outer skin 3 expands and contracts sufficiently in accordance with the bending of the flexible tube 1 of the insertion portion, and the elasticity of the flexible tube 1 of the insertion portion is high.
Therefore, the insertion portion flexible tube 1 is less likely to buckle, and the insertion operability is more excellent. Also, even if used repeatedly, the outer skin 3 is hard to peel off from the core material 2,
It will be excellent in durability.

The thickness of the inner layer 31 is substantially constant along the longitudinal direction. The average thickness of the inner layer 31 is not particularly limited, but is usually preferably 0.05 to 0.8 mm, and more preferably 0.05 to 0.4 mm.

The constituent material of the inner layer 31 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (PE)
T), polyesters such as polybutylene terephthalate,
Polyurethane, polystyrene resin, polytetrafluoroethylene, fluorine-based resin such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, polyurethane-based elastomer, polyester-based elastomer, polyolefin-based elastomer, polyamide-based One or a combination of two or more of various elastomers such as an elastomer, a polystyrene-based elastomer, a fluorine-based elastomer, a silicone rubber, a fluorine rubber, and a latex rubber can be used.

Among these, polyurethane-based elastomers, polyolefin-based elastomers, and polyester-based elastomers are particularly preferred because of their excellent adhesion to the core material 2.

The outer layer 32 is formed on the outermost side of the outer skin 3. The hardness of the outer layer 32 is set relatively high, and is higher than the hardness of the inner layer 31 and the intermediate layer 33. As a result, the outer skin 3 can be used even if it is used repeatedly.
The surface is not easily scratched, and does not easily cause cracks or the like.

Here, usually, when the hardness of the outer layer 32 is made relatively high in consideration of the chemical resistance and the difficulty of scratching, the elasticity (flexibility) of the flexible tube 1 is increased. It may decrease. On the other hand, in the insertion portion flexible tube 1,
By providing the flexible intermediate layer 33 as described later,
There is no such fear.

The thickness of the outer layer 32 varies from the distal end 11 to the proximal end 12.
It gradually increases toward. The average thickness of the outer layer 32 is not particularly limited, but is usually 0.05 to 0.8 m.
m, more preferably 0.05 to 0.4 mm.

The outer layer 32 is preferably made of a material having chemical resistance. Thereby, even if the washing and disinfection are repeatedly performed, the outer skin 3 is hardly deteriorated, and the outer skin 3 hardens, and the flexibility is reduced, and the outer skin 3 is hardly peeled off from the mesh tube 22 due to cracks or the like.

The constituent material of the outer layer 32 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (PE)
T), polyesters such as polybutylene terephthalate,
Polyurethane, polystyrene resin, polytetrafluoroethylene, fluorine-based resin such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimide, polyurethane-based elastomer, polyester-based elastomer, polyolefin-based elastomer, polyamide-based One or a combination of two or more of various elastomers such as an elastomer, a polystyrene-based elastomer, a fluorine-based elastomer, a silicone rubber, a fluorine rubber, and a latex rubber can be used.

Among them, in particular, polyolefins such as ethylene-vinyl acetate copolymer, fluorine resins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer, polyester elastomers, polyolefin elastomers, fluorine elastomers, Silicone rubber and fluoro rubber are preferable because of their excellent chemical resistance.

The intermediate layer 33 is formed between the inner layer 31 and the outer layer 32. The intermediate layer 33 is a layer that is more flexible (excellent in elasticity) than the outer layer 32 and the inner layer 31.

The thickness of the intermediate layer 33 is gradually reduced from the distal end 11 toward the proximal end 12, as opposed to the outer layer 32.
The total thickness of the outer layer 32 and the intermediate layer 33 is substantially constant along the longitudinal direction.

With such a configuration, the outer skin 3 has a substantially constant overall thickness along the longitudinal direction, but has a portion where the ratio of the thickness of the outer layer 32 having high hardness is large (that is, a relatively flexible portion). The smaller the ratio of the thickness of the intermediate layer 33), the greater the rigidity against tension and bending. Therefore,
The outer skin 3 has higher rigidity as it is closer to the base end 12.

Due to the change in the rigidity of the outer cover 3 along the longitudinal direction, the flexibility (bending rigidity) of the flexible tube 1 changes along the longitudinal direction. The bending rigidity of the flexible tube 1 can be freely adjusted by changing the ratio of the thickness of the outer layer 32 to the thickness of the intermediate layer 33. Accordingly, in the flexible tube 1 of the insertion portion, the above-described flexibility change rate can be obtained by appropriately changing the thickness ratio between the outer layer 32 and the intermediate layer 33 along the longitudinal direction.

Also, the intermediate layer 33 is formed by the inner layer 31 and the outer layer 3.
2 is more flexible than the intermediate layer 33.
Exerts a cushioning function between the inner layer 31 and the outer layer 32. For this reason, the elasticity of the insertion portion flexible tube 1 is improved, and the insertion operability is further improved.

The cushion function of the intermediate layer 33 will be described in more detail. When the flexible tube 1 is bent, the elasticity of the intermediate layer 33 is excellent, so that the deformed intermediate layer 33 exerts a strong restoring force. And the middle layer 33
Is sandwiched between the inner layer 31 and the outer layer 32 having relatively high hardness, the restoring force of the intermediate layer 33 is smaller than that of the inner layer 31 and the outer layer 3.
It is transmitted to 2 efficiently. Therefore, almost all of the restoring force of the intermediate layer 33 is used for restoring the bending of the insertion portion flexible tube 1. Therefore, by adopting such a configuration, the flexible tube 1 is excellent in elasticity.

Further, by making the thickness of the outer cover 3 substantially constant along the longitudinal direction, the entire outer diameter of the flexible tube 1 is substantially constant. For this reason, even in a portion having a large bending rigidity near the base end 12, the diameter does not increase, so that the burden and pain on the patient can be further reduced.

The average thickness of the intermediate layer 33 is not particularly limited, but is usually preferably 0.05 to 0.8 mm, more preferably 0.05 to 0.4 mm.

The constituent material of the intermediate layer 33 is not particularly limited. For example, polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyethylene terephthalate (P
ET), polyesters such as polybutylene terephthalate, polyurethanes, polystyrene resins, polytetrafluoroethylene, fluorine resins such as ethylene-tetrafluoroethylene copolymer, various flexible resins such as polyimides, polyurethane elastomers, Among various elastomers such as polyester elastomer, polyolefin elastomer, polyamide elastomer, polystyrene elastomer, fluorine elastomer, silicone rubber, fluorine rubber, latex rubber, etc.
Species or a combination of two or more can be used.

Of these, polyurethane elastomers, polyolefin elastomers and polyester elastomers having low hardness are particularly preferred because of their excellent flexibility (elasticity).

In this embodiment, the intermediate layer 33 has a single-layer structure, but may have a structure in which two or more intermediate layers 33 are formed.

The average thickness of the entire outer skin 3 is not particularly limited, and is usually preferably 0.15 to 0.9 mm, more preferably 0.3 to 0.8 mm.

According to the insertion section flexible tube 1 described above, the inner layer 31, the outer layer 32, and the intermediate layer 33 are provided over the entire length of the laminate constituting the outer cover 3. Also,
It is not necessary to change the composition of the material constituting each of these layers along the longitudinal direction. Therefore, the characteristics of each layer of the laminate do not differ between the portions of the laminate, and are provided over the entire length of the laminate. Therefore, the adhesiveness of the inner layer 31 to the core material 2, the chemical resistance of the outer layer 32, and the flexibility of the intermediate layer 33 can be improved over the entire length of the laminate. Thereby, the durability, chemical resistance, and elasticity of the flexible tube for an endoscope can be improved over the entire length of the laminate. As described above, according to the flexible tube 1 of the insertion portion, a change in flexibility (bending rigidity) along the longitudinal direction can be obtained while maintaining various excellent characteristics over the entire length of the laminate.

The method of manufacturing the flexible tube 1 is not particularly limited. However, the flexible tube 1 can be manufactured continuously by covering the core 2 with the core 2 by extrusion molding. According to the extruder having a plurality of extrusion ports, the inner layer 31, the outer layer 32, and the intermediate layer 33 can be simultaneously extruded, and the laminated body can be coated on the core material 2.

At this time, the thickness of each layer can be freely adjusted by adjusting the supply amount of the constituent material of each layer from each extrusion port (the supply amount per unit time) and the moving speed of the core material 2. it can.

The material temperature during extrusion molding is not particularly limited, but is preferably, for example, about 130 to 220 ° C., and more preferably about 165 to 205 ° C. If the material temperature during extrusion is in such a temperature range,
The material is excellent in formability of the outer cover 3. Therefore, the uniformity of the thickness of the outer cover 3 is improved.

Although the flexible tube for an endoscope of the present invention has been described above, the present invention is not limited to these.

For example, in order to obtain the above-described flexibility change rate, the following configuration may be employed instead of the configuration described above.

When the outer shell is composed of a single layer, the constituent material (composition) of the layer is changed along the longitudinal direction. In the case where the outer skin is formed of a laminate, at least one of the layers is formed by changing the constituent material (composition) of the layer along the longitudinal direction. -When the outer skin is composed of a laminate, the number of layers is changed along the longitudinal direction. For example, the tip portion has a single layer, the middle portion has two layers, and the hand portion has three layers. -The outer skin is formed by connecting two or more tubes with different physical properties.・ Change the wall thickness or spiral pitch of the spiral tube along the longitudinal direction. -It is assumed that the above configuration or a combination of a plurality of configurations other than the above is combined.

[0113]

The present invention will now be described by way of Examples and Comparative Examples.
This will be described in more detail.

1. Production of Flexible Tube for Endoscope (Example 1) First, a stainless steel strip having a width of 3 mm was wound to produce a spiral tube 21 having an outer diameter of 9.9 mm and an inner diameter of 9.6 mm. Next, a braided tube 2 in which ten thin wires of stainless steel having a diameter of φ0.1 mm are arranged in a line at a time.
2 was produced. The spiral tube 21 is covered with the mesh tube 22,
Core material 2 was obtained.

Next, on the outer periphery of the core material 2 by extrusion molding,
An outer skin 3 composed of three layers of an inner layer 31, an outer layer 32, and an intermediate layer 33 was covered to produce a 1.6 m long flexible tube for an endoscope. Therefore, the distal reference point 13 and the proximal reference point 14
(Lmm) is 1350 mm. That is, L = 1350.

The thickness of the inner layer 31 was set to 0.1 mm over the entire length of the flexible tube for an endoscope. The thickness of the outer layer 32 is
1, the position (45) of 0.05 mm and (L / 3) mm
0.25 mm at (0 mm position), (2L / 3) m
0.28 mm at position m (position 900 mm),
The thickness at the base end 12 was 0.4 mm, and the thickness gradually increased at a constant rate in the direction from the front end 11 to the base end 12 between these points.

The thickness of the intermediate layer 33 is 0.35 mm at the tip 11, 0.16 mm at the (L / 3) mm position (450 mm position), and 0.16 mm at the (2L / 3) mm position (900 mm position). 0.15mm, proximal end 12
In each of the points, the thickness gradually decreases at a constant rate in the direction from the distal end 11 to the proximal end 12. Table 1 shows constituent materials of each layer of the outer cover 3 in the flexible tube for an endoscope of Example 1.

(Example 2) A flexible tube for an endoscope was produced in the same manner as in Example 1 except that the thicknesses of the outer layer 32 and the intermediate layer 33 of the outer cover 3 were changed as follows.

The thickness of the outer layer 32 is set at 0.1 at the tip 11.
08mm, (L / 3) mm position (450mm position)
At 0.28 mm, (2L / 3) mm position (90
03), 0.33 mm at the base end 12 and 0.45 mm at the base end 12.
It was set to gradually increase at a fixed rate in the direction from 1 to the base end 12.

The thickness of the intermediate layer 33 is 0.47 mm at the tip 11, 0.27 mm at the (L / 3) mm position (450 mm position), and 0.27 mm at the (2L / 3) mm position (900 mm position). 0.22mm, proximal end 12
In each of the points, the thickness gradually decreases at a constant rate in the direction from the front end 11 to the base end 12. Table 1 shows constituent materials of each layer of the outer cover 3 in the flexible tube for an endoscope of Example 2.

(Comparative Example 1) The outer periphery of a core material 2 similar to that of Example 1 was covered with an outer skin composed of two layers of an inner layer 31 and an outer layer 32 by extrusion molding, and an endoscope having a length of 1.6 m was obtained. A flexible tube for a mirror was manufactured.

The thickness of the inner layer 31 is set at 0.1 at the tip 11.
5 mm, 0.35 mm at the proximal end 12 and the distal end 11
From the base end 12 at a constant rate.

The outer layer 32 has a thickness of 0.1 mm at the tip 11.
05 mm, 0.2 mm at the proximal end 12, and
From the base end 12 to the base end 12 at a constant rate. Table 1 shows constituent materials of each layer of the outer cover 3 in the flexible tube for an endoscope of Comparative Example 1.

(Comparative Example 2) The outer periphery of a core material 2 similar to that of Example 1 was covered with an outer skin composed of two layers of an inner layer 31 and an outer layer 32 by extrusion molding, and an endoscope having a length of 1.6 m was obtained. A flexible tube for a mirror was manufactured.

The inner layer 31 has a thickness of 0.1 mm at the tip 11.
37mm, (L / 3) mm position (450mm position)
At a position of 0.35 mm and (2L / 3) mm (90
06 mm) and 0.03 mm at the proximal end 12, and the thickness between the points is
In the direction from 1 toward the base end 12, the pressure gradually decreases at a constant rate.

The thickness of the outer layer 32 is set at 0.1 at the tip 11.
03mm, (L / 3) mm position (450mm position)
At a position of 0.2 mm and (2L / 3) mm (900
mm) and 0.39 mm at the proximal end 12, and the thickness between the points is
From the base end 12 toward the base end 12 at a constant rate. Table 1 shows constituent materials of each layer of the outer cover 3 in the flexible tube for an endoscope of Comparative Example 2.

[0127]

[Table 1]

The materials A to E in Table 1 are as follows. Material A: Medium hardness polyurethane elastomer (JIS
Material A: Low-hardness polyurethane-based elastomer (JIS according to K 7311)
Material A: High hardness polyester elastomer (JIS)
Material D: Medium hardness polyurethane-based elastomer (JIS)
Material A: High hardness polyolefin-based elastomer (JIS)
Hardness according to K 7311 A 95 °)

[0129] 2. Measurement of rate of change in flexibility The rate of change in flexibility of the flexible tube for an endoscope in each of the examples and comparative examples was measured. First, according to the above-described method, the distal-side reference point 13 (0 mm position), the proximal-side reference point 14 (Lmm position), and the distal-side reference point 13 and the proximal-side reference point 14.
The bending stiffness at each point that divides 15 into 15 was measured.

The bending stiffness of the distal-side reference point 13 was determined for each of the flexible tubes for endoscopes of the examples and the comparative examples.
It is shown in Table 2.

Also, the tip side reference point 13 (0 mm position)
Where the bending stiffness is 1, the position (0 mm position, (L / 15) mm position, (2L
/ 15) mm, (L / 5) mm, (4L /
Table 2 shows the magnitude (ratio) of the bending stiffness at the position of 15) mm and at the position of (L / 3) mm) for the flexible tubes for endoscopes of each of the examples and the comparative examples.

[0132]

[Table 2]

When the bending stiffness at the position of (L / 3) mm is set to 1, each point ((L / 3) m
m position, (2L / 5) mm position, (7L / 15) m
m position, (8L / 15) mm position, (3L / 5) m
Table 3 shows the magnitude (ratio) of the bending rigidity at the position of m and at the position of (2L / 3) mm for the flexible tubes for endoscopes of each of the examples and the comparative examples.

[0134]

[Table 3]

When the bending stiffness at the position of (2L / 3) mm is set to 1, each point ((2L / 3
3) mm position, (11L / 15) mm position, (4L
/ 5) mm position, (13L / 15) mm position, (1
Table 4 shows the magnitude (ratio) of the bending rigidity at the position of 4 L / 15) mm and the position of L mm) for the flexible tubes for endoscopes of each of the examples and the comparative examples.

[0136]

[Table 4]

From the values of the bending stiffness at each point of the tip 15 shown in Table 2, the rate of change in the flexibility of the tip 15, 5 · B ｛L / 1
5,0｝, (5/2) · B {2L / 15,0}, (5 /
3) · B ｛L / 5,0｝, (5/4) · B ｛4L / 1
5,0} and B {L / 3,0}. These values are shown in Table 5 for the flexible tube for an endoscope of each of the examples and the comparative examples.

[0138]

[Table 5]

From the values of the bending stiffness at each point of the intermediate portion 16 shown in Table 3, the rate of change in the flexibility of the intermediate portion 16 was calculated as 5 · B ・ 2L /
5, L / 3｝, (5/2) · B ｛7L / 15, L /
3｝, (5/3) · B {8L / 15, L / 3｝, (5 /
4) · B {3L / 5, L / 3} and B {2L / 3, L
/ 3} is required. These values are shown in Table 6 for the flexible tube for an endoscope of each of the examples and the comparative examples.

[0140]

[Table 6]

From the values of the bending stiffness at each point of the hand portion 17 shown in Table 4, the rate of change in the flexibility of the hand portion 17 was calculated as follows: 5 · B ｛11 L /
15,2L / 3｝, (5/2) · B ｛4L / 5,2L /
3｝, (5/3) · B {13L / 15, 2L / 3},
(5/4) · B {14L / 15, 2L / 3} and B
{L, 2L / 3} is obtained. These values are shown in Table 7 for the flexible tube for an endoscope of each of the examples and the comparative examples.

[0142]

[Table 7]

3. Evaluation of operability of insertion of flexible tube for endoscope The operability of insertion of each flexible tube for endoscope produced in each of Examples and Comparative Examples was evaluated.

An electronic endoscope 10 shown in FIG. 1 was manufactured using each flexible tube for an endoscope as a flexible tube for an insertion portion. The insertion portion of each of the manufactured electronic endoscopes 10 was inserted into a biological model imitating a human body cavity, and a portion corresponding to the large intestine of the biological model was inserted until the distal end of the insertion portion (the distal end of the curved portion 5) passed.

In the evaluation of the operability of the insertion, the operability of the insertion at that time is determined by the pushability (the pushing force applied from the hand 17 is reliably transmitted to the tip 11) and the torque transmission (the hand 17). The tip 11 surely follows the torsion added to the rotation) and rotates).
The evaluation was made according to the scale of the scale.

◎: Very good indentation (or torque transmission),
The insertion operation can be performed smoothly. ：: The pushability (or torque transmission) is good, and the insertion operation can be performed almost without hindrance. Δ: Pushing property (or torque transmitting property) is somewhat poor, and it takes time to insert and cannot be inserted quickly. X: The pushability (or torque transmission) is poor, and insertion is not possible within a reasonable time. Table 8 shows the evaluation results of the operability of insertion.

[0147]

[Table 8]

As is evident from the results shown in Table 8, the electronic endoscope 10 manufactured using the flexible tube for an endoscope of Examples 1 and 2 has excellent pushability and torque transmission. Was. In addition, the followability to the lumen was excellent. For this reason, it was possible to insert the target site quickly (within 5 minutes).

On the other hand, in the electronic endoscope 10 manufactured using the flexible tube for an endoscope of Comparative Example 1, a portion having a low bending rigidity was generated, and the pushability and the torque transmission were inferior. For this reason, it was not possible to insert the target site within 10 minutes.

Further, in the electronic endoscope 10 manufactured using the flexible tube for an endoscope of Comparative Example 2, it is assumed that the bending rigidity is too large from the middle of the flexible tube of the insertion portion and is almost inflexible. Therefore, the followability of the portion to the curved lumen was extremely poor. For this reason, the tip of the insertion portion (the tip of the curved portion 5) could not reach the target site. Therefore, the operability of insertion could not be evaluated.

[0151]

As described above, according to the present invention, it is possible to optimize the rate of change of flexibility along the longitudinal direction of the flexible tube for an endoscope, thereby improving the pushability and torque transmission. Operability is improved, and thus excellent insertion operability is obtained.

In particular, by optimizing the flexibility of the distal end portion and the rate of change thereof, excellent followability to the body cavity can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall view showing an electronic endoscope having an insertion portion flexible tube to which the endoscope flexible tube of the present invention is applied.

FIG. 2 is a longitudinal sectional view showing the overall appearance of an insertion portion flexible tube to which the endoscope flexible tube of the present invention is applied.

FIG. 3 is a longitudinal sectional view showing a method for measuring the flexibility of a flexible tube for an endoscope.

FIG. 4 is a longitudinal sectional view of the flexible tube of the insertion portion shown in FIG. 2;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 insertion section flexible tube 11 distal end of insertion section flexible tube 12 proximal end of insertion section flexible tube 13 distal reference point 14 proximal reference point 15 distal section 16 middle section 17 hand section 2 core material 21 spiral pipe 22 Reticulated tube 23 Space 3 Outer skin 31 Inner layer 32 Outer layer 33 Intermediate layer 5 Bending section 6 Operating section 61, 62 Operating knob 7 Connecting section flexible tube 8 Light source insertion section 81 Light source connector 82 Image signal connector 90 Knife edge 10 Electronic Endoscope

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yutaka Abe 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. (72) Inventor Tadashi Kasai 2-36, Maenocho, Itabashi-ku, Tokyo 9 Asahi Gaku Kogyo Co., Ltd. F term (reference) 3H111 AA02 BA01 BA15 BA18 CA03 CB06 CB14 CB29 DA26 DB21 EA04 EA17 4C061 FF24 HH31 JJ01 JJ06

Claims (10)

[Claims] 1. A flexible tube for an endoscope, wherein a position at a distance of 125 mm in a proximal direction from a distal end of the flexible tube for an endoscope is set as a distal-side reference point, When a position at a distance of 125 mm in the distal direction from the proximal end of the flexible tube is defined as a proximal-side reference point, and a length between the distal-side reference point and the proximal-side reference point is defined as Lmm, the following expression ( The rate of change of flexibility B {X, Y} determined by I) is given by B {X, Y} = {W (X) -W (Y)} / W (Y) (I) , W (X) and W (Y) are measured at positions X mm and Y mm in the proximal direction from the distal-side reference point, respectively, and the measurement points are defined as two knife edges having a span of 200 mm. The flexible tube for the endoscope is supported so as to be at the center of the span, and the measurement point is pressed, and the measurement point is moved 50 degrees in the pressing direction. represents the magnitude of the pressing force when displaced by m.) 0.2 ≦ B {L / 3, 0} ≦ 1.5, 0 ≦ B {2L / 3, L / 3} ≦ 0.4, and , 0 ≦ B
A flexible tube for an endoscope, which satisfies the relationship of {L, 2L / 3} ≦ 0.5. 2. The rate of change in flexibility B {X, Y} is B {L / 3, 0}> B {L, 2L / 3}> B｝ 2L /
The flexible tube for an endoscope according to claim 1, wherein a relationship of 3, L / 3｝ is satisfied. 3. The flexibility change rate B {X, Y} is 1 to 3.
For all m that is an integer of 4, 0.2 ≦ (5 / m) · B {mL / 15,0} ≦ 1.5, 0 ≦ (5 / m) · B} (m + 5) · L / 15, L / 3｝
≦ 0.4 and 0 ≦ (5 / m) · B ｛(m + 10)
3. The flexible tube for an endoscope according to claim 1, wherein the following relationship is satisfied: L / 15, 2L / 3 ／ 0.5. 4. The rate of change in flexibility B {X, Y} is 0 to 4.
The endoscope according to any one of claims 1 to 3, wherein a relation of B {(nL / 15 + L / 15), (nL / 15)} ≥0 is satisfied for all n that is an integer of 14. Flexible tube. 5. The endoscope according to claim 1, wherein the magnitude W (0) of the pressing force with the distal-side reference point as a measurement point is 1.0 to 9N. Flexible tube. 6. The flexible tube for an endoscope according to claim 1, comprising a tubular core material and a single-layer or multi-layer laminated outer skin coated on the outer periphery of the core material. 7. The flexibility is changed along the longitudinal direction by changing the thickness and / or the constituent material of at least one of the layers constituting the outer skin along the longitudinal direction. The flexible tube for an endoscope according to claim 6. 8. The outer shell has a portion composed of a laminate having an inner layer, an outer layer, and at least one intermediate layer located therebetween.
4. The flexible tube for an endoscope according to claim 1. 9. The flexible tube for an endoscope according to claim 6, wherein the outer cover is formed by coating an outer periphery of the core material by extrusion molding. 10. The core material includes: a spiral tube formed by spirally winding a strip-shaped material; and a braided body formed by braiding a thin wire, which is coated on an outer periphery of the spiral tube and braided. 10. The flexible tube for an endoscope according to any one of 6 to 9.