Patent Publication Number: US-2020288945-A1

Title: Insertion apparatus, connection structure of exterior member, and endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2018/034477 filed on Sep. 18, 2018 and claims benefit of Japanese Application No. 2017-230644 filed in Japan on Nov. 30, 2017, the entire contents of which are incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an insertion apparatus which includes a first exterior member, and a second exterior member disposed at a position where the second exterior member is adjacent to the first exterior member in a longitudinal axis direction of the first exterior member, a connection structure of an exterior member, and an endoscope. 
     2. Description of the Related Art 
     Recently, an insertion apparatus such as an endoscope has been widely used in the medical field and the industrial field. 
     With respect to an endoscope, the endoscope having the following structure is well known, that is, the endoscope including: an insertion portion which is inserted into a subject; an operation portion which is connected to a proximal end of the insertion portion (hereinafter, simply referred to as a proximal end) in a direction along a longitudinal axis of the insertion portion (hereinafter, simply referred to as a longitudinal axis direction); a universal cord which extends from the operation portion; and a connector which is mounted on an extending end of the universal cord and is detachably connected to an external apparatus. 
     In the endoscope having such a configuration, with respect to an exterior of the endoscope, for example, an exterior of the operation portion of the endoscope, there has been well known a configuration where the exterior is formed by connecting a plurality of exterior members along the above-mentioned longitudinal axis. 
     For example, there has been well known a configuration where an exterior of an operation portion is formed by connecting along the longitudinal axis a first exterior member formed in a barrel shape and a second exterior member disposed at a position adjacently to the first exterior member in a longitudinal axis direction and formed in a barrel shape. 
     More specifically, there has also been well known a structure where a first exterior member and a second exterior member are connected to each other in a state where a small diameter part having a barrel shape and a narrow diameter which is formed on a distal end side of the second exterior member in the longitudinal axis direction (hereinafter, simply referred to as a distal end side) is inserted into the -first exterior member, and an end surface of a part of the second exterior member having a diameter which changes is made to abut against a proximal end surface of the first exterior member along the longitudinal axis so that the end surface is positioned along the longitudinal axis. 
     There has been also well known a structure where a watertight state of a connection part is maintained by bringing a water tightness maintaining member such as an O-shaped ring mounted on an outer peripheral surface of a small diameter part into contact with an inner peripheral surface of a first exterior member. 
     Further, in Japanese Patent Application Laid-Open Publication No. 2006-130238, a configuration is disclosed where an elastically deformable sealing member is filled in a gap at a connection part between exterior members, and the gap between the exterior members is sealed by collapsing the sealing member between both exterior members along a longitudinal axis. 
     In the above-mentioned configuration where the first exterior member and the second exterior member are connected to each other, it is necessary to provide a positioning member to at least one of the first exterior member and the second exterior member so as to prevent the occurrence of a phenomenon that the first exterior member is rotated with respect to the second exterior member in a circumferential direction, or a phenomenon that the first exterior member is displaced with respect to the second exterior member along the longitudinal axis for controlling a compression amount of the sealing member. 
     This is because when the position of the first exterior member with respect to the second exterior member is displaced in the longitudinal axis direction and in the circumferential direction, accuracy in collapsing the sealing member (a control of a compression amount) between both exterior members becomes unstable and hence, an external appearance of a connection part does not become smooth and exhibits poor appearance. 
     In view of such circumstances, for example, there has been also well known a configuration where positioning between both exterior members is performed by making a convex portion formed on an outer peripheral surface of a small diameter part and a recessed portion formed on an inner peripheral surface of the first exterior member engage with each other by fitting. 
     SUMMARY OF THE INVENTION 
     An insertion apparatus according to an aspect of the present invention includes: a first exterior member; a second exterior member disposed at a position where the second exterior member is adjacent to the first exterior member in a longitudinal axis direction of the first exterior member; a sealing member disposed at a connection part between the first exterior member and the second exterior member in the longitudinal axis direction, the sealing member being configured to deform elastically; and a positioning member disposed in a spaced-apart manner from the sealing member in the longitudinal axis direction or in a circumferential direction around a longitudinal axis of the first exterior member, the positioning member configured to position the first exterior member with respect to the second exterior member in the longitudinal axis direction and in the circumferential direction. 
     A connection structure of an exterior member according to an aspect of the present invention includes: a first exterior member; a second exterior member disposed at a position where the second exterior member is adjacent to the first exterior member in a longitudinal axis direction of the first exterior member; a sealing member disposed at a connection part between the first exterior member and the second exterior member in the longitudinal axis direction, the sealing member being configured to deform elastically; and a positioning member disposed in a spaced-apart manner from the sealing member in the longitudinal axis direction or in a circumferential direction around a longitudinal axis of the first exterior member, the positioning member configured to position the first exterior member with respect to the second exterior member in the longitudinal axis direction and in the circumferential direction. 
     An endoscope according to an aspect of the present invention includes: an operation portion which includes a first exterior member, a second exterior member disposed at a position where the second exterior member is adjacent to the first exterior member in a longitudinal axis direction of the first exterior member, and a sealing member disposed at a connection part between the first exterior member and the second exterior member in the longitudinal axis direction, the sealing member being configured to deform elastically; and an insertion portion connected to the operation portion on a first exterior member side, wherein the first exterior member and the second exterior member include a positioning member disposed in a spaced-apart manner from the sealing member in the longitudinal axis direction or in a circumferential direction around a longitudinal axis of the first exterior member, the positioning member configured to position the first exterior member with respect to the second exterior member in the longitudinal axis direction and in the circumferential direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing an external appearance of an endoscope according to an embodiment; 
         FIG. 2  is a plan view showing an exterior of an operation portion in  FIG. 1  in an enlarged manner; 
         FIG. 3  is a cross-sectional view of the exterior of the operation portion taken along a line III-III in  FIG. 2 ; 
         FIG. 4  is a cross-sectional view of the exterior of the operation portion taken along a line IV-IV in  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of the exterior of the operation portion taken along a line V-V in  FIG. 2 ; 
         FIG. 6  is an enlarged cross-sectional view of a part in  FIG. 5  surrounded by a line VI; 
         FIG. 7  is an enlarged cross-sectional view of a part in  FIG. 3  surrounded by a line VII; 
         FIG. 8  is an enlarged cross-sectional view of a part in  FIG. 7  surrounded by a line VIII; 
         FIG. 9  is a cross-sectional view of the exterior of the operation portion taken along a line IX-IX in  FIG. 7 ; 
         FIG. 10  is a partial perspective view schematically showing a recessed portion formed on an inner peripheral surface of a distal end of a small diameter part of a second exterior member in  FIG. 7 ; 
         FIG. 11  is a partial perspective view schematically showing an end portion side of a convex portion in  FIG. 7  which engages with the recessed portion in  FIG. 10 ; and 
         FIG. 12  is a partial perspective view schematically showing a state where the convex portion in  FIG. 11  engages with the recessed portion in  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Hereinafter, an embodiment of the present invention is described with reference to drawings. Drawings are schematic views. Accordingly, it should be kept in mind that a relationship between a thickness and a width of each member, a ratio between thicknesses of respective members and the like differ from the corresponding relationships of members of an actual insertion apparatus. Needless to say, portions of the insertion apparatus are described with different size relationships or different ratios between the drawings. 
     In the embodiment described hereinafter, the description is made by taking an endoscope as an example of an insertion apparatus. 
       FIG. 1  is a view showing an external appearance of an endoscope according to this embodiment.  FIG. 2  is a plan view showing an exterior of an operation portion in  FIG. 1  in an enlarged manner.  FIG. 3  is a cross-sectional view of the exterior of the operation portion taken along a line III-III in  FIG. 2 .  FIG. 4  is a cross-sectional view of the exterior of the operation portion taken along a line IV-IV in  FIG. 3 .  FIG. 5  is a cross-sectional view of the exterior of the operation portion taken along a line V-V in  FIG. 2 . 
       FIG. 6  is an enlarged cross-sectional view of a part in  FIG. 5  surrounded by a line VI.  FIG. 7  is an enlarged cross-sectional view of a part in  FIG. 3  surrounded by a line VII.  FIG. 8  is an enlarged cross-sectional view of a part in  FIG. 7  surrounded by a line VIII.  FIG. 9  is a cross-sectional view of the exterior of the operation portion taken along a line IX-IX in  FIG. 7 . 
       FIG. 10  is a partial perspective view schematically showing a recessed portion formed on an inner peripheral surface of a distal end of a small diameter part of a second exterior member in  FIG. 7 .  FIG. 11  is a partial perspective view schematically showing an end portion side of a convex portion in  FIG. 7  which engages with the recessed portion in  FIG. 10 .  FIG. 12  is a partial perspective view schematically showing a state where the convex portion in  FIG. 11  engages with the recessed portion in  FIG. 10 . 
     As shown in  FIG. 1 , a main part of the endoscope  1  is formed of: an insertion portion  2  which has flexibility, is inserted into a subject, and extends in a longitudinal axis direction N which is a direction of a longitudinal axis; an operation portion  6  which is connected to a proximal end of the insertion portion  2  by way of a bend preventing member  15  in the longitudinal axis direction N; a universal cord  11  which extends from the operation portion  6  by way of a bend preventing member  16 ; and a connector  12  which is mounted on an extending end of the universal cord  11 . 
     The endoscope  1  is electrically connected to external apparatuses such as a controller and an illumination apparatus by way of the connector  12 . 
     A treatment instrument insertion opening  13  is formed on the operation portion  6 . The treatment instrument insertion opening  13  is formed so as to allow a treatment instrument to be inserted into a subject through a treatment instrument insertion tube passage (not shown in the drawing) formed in the insertion portion  2  and the operation portion  6 . 
     The operation portion  6  includes: a vertical bending operation knob  7  which bends a bending portion  4  (described later) of the insertion portion  2  in a vertical direction; and a lateral bending operation knob  9  which bends the bending portion  4  in a lateral direction. 
     The operation portion  6  further includes: a fixing lever  8  which fixes a rotary position of the vertical bending operation knob  7 ; and a fixing knob  10  which fixes a rotary position of the lateral bending operation knob  9 . 
     The insertion portion  2  includes a distal end portion  3 , the bending portion  4 , and a flexible tube portion  5  which are arranged in this order from a distal end side, and is formed in an elongated shape. 
     The bending portion  4  is bent in a plurality of directions, for example, in four directions, that is, in the upward, downward, leftward, and rightward directions due to rotary operations of the vertical bending operation knob  7  and the lateral bending operation knob  9  mounted on the operation portion  6 . With such operations, the bending portion  4  can change an observation direction of an observation optical system (not shown in the drawing) which is mounted in the distal end portion  3 , and can enhance inserting ability of the distal end portion  3  into a subject. 
     The flexible tube portion  5  is connected to a proximal end side of the bending portion  4  in the longitudinal axis direction N (hereinafter, simply referred to as a proximal end side), and has flexibility to an extent that the flexible tube portion  5  can be bent in a passive manner. 
     As shown in  FIG. 2 to 5 , an exterior  6   g  of the operation portion  6  is formed of: a first exterior member  30  which is positioned on a bend preventing member  15  side and on which the treatment instrument insertion opening  13  is formed; and a second exterior member  50  which is disposed at a proximal end of the first exterior member  30 , that is, at a position disposed adjacently to the first exterior member  30  in the longitudinal axis direction N. Various knobs  7 ,  9 , and  10  and the lever  8  described above are mounted on the second exterior member  50 . 
     As shown in  FIG. 3  to  FIG. 5 , the first exterior member  30  and the second exterior member  50  are respectively formed in an elongated barrel shape in the longitudinal axis direction N. 
     As shown in  FIG. 3  to  FIG. 5  and  FIG. 7 , a small diameter part  51  having a diameter narrowed in an inside direction KI with respect to a radial direction K is formed on a distal end side of the second exterior member  50 , and the second exterior member  50  is connected to the first exterior member  30  due to engagement of the small diameter part  51  with an inner periphery of the first exterior member  30  on a proximal end side. 
     An O-shaped ring groove  51   w  is formed in a circumferential shape on an outer peripheral surface  51   g  of the small diameter part  51  in a circumferential direction C. An O-shaped ring  60  which is a water tightness maintaining member is fitted in the O-shaped ring groove  51   w.    
     Due to the provision of the O-shaped ring  60  fitted in the O-shaped ring groove  51   w,  when the small diameter part  51  is fitted and coupled in an inner periphery of the first exterior member  30  on a proximal end side, watertight sealing is provided between an inner peripheral surface  30   n  of the first exterior member  30  and the outer peripheral surface  51   g  of the small diameter part  51 . 
     The O-shaped ring  60  is disposed more inside than a sealing member  40  described later in the radial direction K. 
     A radius of the second exterior member  50  changes at a part of the outer peripheral surface  51   g  of the small diameter part  51  disposed at a position on a more proximal end side than the O-shaped ring groove  51   w.  A sealing member fitting groove  51   v  is formed circumferentially on this part. 
     The sealing member  40  which is elastically deformable and has a ring-shape is fitted in the sealing member fitting groove  51   v  in an exposed manner to the outside, the sealing member fitting groove  51   v  being disposed at a connecting portion F which is a connection part between the first exterior member  30  and the second exterior member  50  in the longitudinal axis direction N. 
     In other words, the sealing member  40  fitted in the sealing member fitting groove  51   v  is a member which, when the second exterior member  50  is connected to the first exterior member  30 , seals a gap formed between a proximal end surface  30   k  of the first exterior member  30  and an end surface  50   s  of the sealing member fitting groove  51   v  of the second exterior member  50  in the radial direction K in the longitudinal axis direction N. Such sealing is provided by the elastic deformation of the sealing member  40  generated by compression of the sealing member  40  by the proximal end surface  30   k  and the end surface  50   s  in the longitudinal axis direction N. 
     In this case, as shown in  FIG. 8 , a compressive cross-sectional area B of the sealing member  40  may preferably be formed smaller than a space cross-sectional area A defined by the sealing member  40 , an outer peripheral surface  30   g  of the first exterior member  30  and an outer peripheral surface  50   g  of the second exterior member  50 . With such a configuration, when the sealing member  40  is compressed in the longitudinal axis direction N, there is no possibility that the sealing member  40  projects from the sealing member fitting groove  51   v  in an outside direction KO with respect to the radial direction K relative to the outer peripheral surfaces  30   g,    50   g  and hence, an external appearance of the connecting portion F becomes smooth whereby the external appearance of the connecting portion F is enhanced. 
     As shown in  FIG. 9 , an inner peripheral surface  40   n  of the sealing member  40  disposed circumferentially is formed into a shape where, in a non-compressed state, only two protruding portions  40   d  which protrude in the inside direction KI with respect to the radial direction K and face each other are brought into contact with a bottom surface of the sealing member fitting groove  51   v.    
     In other words, when the sealing member  40  disposed circumferentially is in a non-compressed state, the inner peripheral surface  40   n  is disposed with a gap S formed between the sealing member  40  and the bottom surface of the sealing member fitting groove  51   v  except for two protruding portions  40   d.    
     The reason is as follows. When the sealing member  40  is compressed in the longitudinal axis direction N, a diameter enlarging direction of the sealing member  40  with respect to the radial direction K is guided in the inside direction KI due to the gap S, that is, the gap S absorbs the compression of the sealing member  40 . Accordingly, it is possible to prevent the occurrence of a phenomenon that a diameter of the sealing member  40  is enlarged in the outside direction KO so that the sealing member  40  projects from the sealing member fitting groove  51   v  in the outside direction KO whereby an external appearance of the connecting portion F can be enhanced. 
     Further, only two protruding portions  40   d  which face each other are brought into contact with the inner peripheral surface  40   n  and hence, positioning of the sealing member  40  in the sealing member fitting groove  51   v  in a circumferential direction C can be easily performed. 
     To enhance an external appearance of the connecting portion F, the sealing member  40  may be integrally formed with either the first exterior member  30  or the second exterior member  50 . 
     In this case, a seam between the sealing member  40  and the first exterior member  30  or the second exterior member  50  becomes smooth when the sealing member  40  is integrally formed with the first exterior member  30  or the second exterior member  50  and hence, the external appearance of the connecting portion F is enhanced. 
     The sealing member  40  is formed with an elastic modulus smaller than an elastic modulus of the first exterior member  30  and an elastic modulus of the second exterior member  50 . 
     The reason is as follows. In a case where the elastic modulus of the sealing member  40  is set higher than the elastic modulus of the first exterior member  30  and the elastic modulus of the second exterior member  50 , when the sealing member  40  is compressed in the longitudinal axis direction N by the proximal end surface  30   k  and the end surface  50   s,  the first exterior member  30  and the second exterior member  50  are deformed. 
     In other words, with the above-mentioned configuration, the deformation of the first exterior member  30  and the second exterior member  50  can be prevented and hence, the external appearance of the connecting portion F can be enhanced. 
     As shown in  FIG. 6  and  FIG. 10 , a protruding portion  52  which protrudes in the inside direction KI with respect to the radial direction K and has a circumferential shape in a circumferential direction C is formed on a distal end of an inner peripheral surface  51   n  of the small diameter part  51  in the longitudinal axis direction N (hereinafter, simply referred to as the distal end). 
     A recessed portion  53  is formed in a part of the protruding portion  52  in the circumferential direction C. The recessed portion  53  has a shape where a side of the recessed portion  53  in the inside direction KI is closed, and the recessed portion  53  penetrates the protruding portion  52  in the longitudinal axis direction N. 
     A plurality of recessed portions  53  may be formed in the protruding portion  52  in the circumferential direction C. 
     Further, as shown in  FIG. 5 ,  FIG. 7 , and  FIG. 12 , after the first exterior member  30  is connected to the second exterior member  50 , with respect to the inner peripheral surface  30   n  of the first exterior member  30  on a proximal end side, at a position in the circumferential direction C which faces the recessed portion  53  in the longitudinal axis direction N which is also the position disposed in a spaced-apart manner from the sealing member  40  in the radial direction K and in the longitudinal direction N, more specifically, at the position on a more distal end side than the sealing member  40  and the O-shaped ring  60 , two convex portions  31 ,  32  and two longitudinal positioning convex portions  33  are respectively formed. These convex portions  31 ,  32  and longitudinal positioning convex portions  33  are formed as positioning members for positioning the first exterior member  30  with respect to the second exterior member  50  in the longitudinal axis direction N and the circumferential direction C along with abutting and contacting of the first exterior member  30  to the second exterior member  50 . 
     The convex portions  31 ,  32 , and two longitudinal positioning convex portions  33  are formed in an elongated shape in the longitudinal axis direction N, and are formed in a shape projecting from the inner peripheral surface  30   n  in the inside direction KI with respect to the radial direction K. 
     When the first exterior member  30  and the second exterior member  50  are connected to each other, as shown in  FIG. 7  and  FIG. 12 , the respective end surfaces  33   m  of two longitudinal positioning convex portions  33  abut against a distal end surface  52   m  of the protruding portion  52  so that the first exterior member  30  is positioned with respect to the second exterior member  50  in the longitudinal axis direction N. 
     With such a configuration, it is possible to prevent the occurrence of a phenomenon that the sealing member  40  is excessively compressed so that a compression amount is increased whereby the sealing member  40  projects from the outer peripheral surfaces  30   g,    50   g  in the outside direction KO. 
     As shown in  FIG. 11 , notched portions  31   h,    32   h  are respectively formed on the convex portions  31 ,  32  such that the diameters of the convex portions  31 ,  32  become small on a distal end side in the outside direction KO with respect to the radial direction K. As a result, protruding projections  31   i,    32   i  are respectively formed on the convex portions  31 ,  32 . 
     The protruding projections  31   i,    32   i  engage with the recessed portion  53  by fitting when the first exterior member  30  and the second exterior member  50  are connected to each other. 
     As shown in  FIG. 6  and  FIG. 12 , notched surfaces  31   m,    32   m  which are formed by the notched portions  31   h,    32   h  of the convex portions  31 ,  32  form abutting surfaces which abut against the distal end surface  52   m  of the protruding portion  52  when the protruding projections  31   i,    32   i  engage with the recessed portion  53 . 
     Due to abutting of the notched surfaces  31   m,    32   m  against the distal end surface  52   m,  when the first exterior member  30  and the second exterior member  50  are connected to each other, the first exterior member  30  is positioned with respect to the second exterior member  50  in the longitudinal axis direction N. 
     With such a configuration, it is possible to prevent the occurrence of a phenomenon that the sealing member  40  is excessively compressed so that a compression amount is increased whereby the sealing member  40  projects from the outer peripheral surfaces  30   g,    50   g  in the outside direction KO. 
     Positioning of the first exterior member  30  with respect to the second exterior member  50  may be performed using only the above-mentioned longitudinal positioning convex portions  33  without using the convex portions  31 ,  32 . Conversely, positioning of the first exterior member  30  with respect to the second exterior member  50  may be performed using only the convex portions  31 ,  32  without using the longitudinal positioning convex portions  33 . 
     As shown in  FIG. 6 ,  FIG. 10 , and  FIG. 12 , outer peripheral side surfaces  31   d,    32   d  of the protruding projections  31   i,    32   i  in the outside direction KO with respect to the radial direction K form contact surfaces which are brought into contact with respective opening end surfaces  52   r  of the recessed portion  53  substantially parallel to the longitudinal axis direction N when the protruding projections  31   i,    32   i  engage with the recessed portion  53 . 
     Since the outer peripheral side surfaces  31   d,    32   d  are brought into contact with the respective opening end surfaces  52   r,  when the first exterior member  30  and the second exterior member  50  are connected to each other, the first exterior member  30  is positioned with respect to the second exterior member  50  in the circumferential direction C. 
     The reason why the positioning member is formed of two convex portions such as the convex portions  31 ,  32  is as follows. With the use of two convex portions, a strength of the positioning member can be increased with certainty compared to the case where one convex portion is used. Accordingly, the positioning member may be formed of one convex portion in the case where such requirement can be ignored. 
     In the case where a plurality of recessed portions  53  are formed with respect to the protruding portions  52  in a circumferential direction C, two convex portions  31 ,  32  may be formed on the inner peripheral surface  30   n  for each recessed portion  53 . 
     Other configurations are equal to the corresponding configurations of the conventional exterior  6   g.    
     In this manner, according to this embodiment, the case is described where the first exterior member  30  and the second exterior member  50  are connected to each other and, thereafter, positioning of the first exterior member  30  with respect to the second exterior member  50  in the longitudinal axis direction N and the circumferential direction C is performed by making the convex portions  31 ,  32  engage with the recessed portion  53  at a position other than the connecting portion F, more specifically, at the position in a spaced-apart manner in the inside direction KI. with respect to the radial direction K relative to the sealing member  40  and also in a spaced-apart manner toward a distal end side in the longitudinal axis direction N relative to the sealing member  40  and the O-shaped ring  60 . 
     In this manner, the configuration where positioning is performed in the vicinity of the sealing member  40  and the O-shaped ring  60  at the connecting portion F is not adopted and hence, it is possible to prevent a diameter of the connecting portion F from becoming large-sized due to the positioning member. 
     Positioning of the first exterior member  30  with respect to the second exterior member  50  in the longitudinal axis direction N can be performed with certainty by making the respective notched surfaces  31   m,    32   m  abut against the distal end surface  52   m  and hence, a compression amount of the sealing member  40  can be controlled with high accuracy. Further, positioning of the first exterior member  30  with respect to the second exterior member  50  in the circumferential direction C can be performed with certainty by bringing the outer peripheral side surfaces  31   d,    32   d  into contact with the respective opening end surfaces  52   r.    
     In this manner, since there is no possibility that the first exterior member  30  is displaced with respect to the second exterior member  50  in the longitudinal axis direction N and in the circumferential direction C, that is, since the positioning accuracy can be enhanced, excessive compression of the sealing member  40  can be prevented. Accordingly, an external appearance of the endoscope  1  at the connecting portion F can be enhanced. 
     As has been described above, it is possible to provide the endoscope  1  having the configuration where the first exterior member  30  can be positioned with respect to the second exterior member  50  in the longitudinal axis direction N and in the circumferential direction C with a favorable external appearance without increasing the diameter of the connecting portion F. 
     In the above-mentioned embodiment, the exterior  6   g  has been described by taking the case where the exterior  6   g  is firmed of two exterior members consisting of the first exterior member  30  and the second exterior member  50  as an example. Needless to say, the present invention is applicable to a connection structure where three or more exterior members are connected to each other. 
     In the above-mentioned embodiment, the configuration is described where the small diameter part  51  of the second exterior member  50  is inserted into the first exterior member  30 . However, as an opposite case, the present invention is also applicable to a configuration where a small diameter part formed on the proximal end side of the first exterior member  30  is inserted into the second exterior member  50 . 
     The insertion apparatus is described by exemplifying the endoscope. However, the present invention is not limited to such an endoscope. Needless to say, the present invention is applicable to other insertion apparatuses such as a treatment instrument. 
     The exterior of the insertion apparatus is also not limited to the exterior  6   g  of the operation portion  6  of the endoscope  1 . Needless to say, the present invention is applicable to the connection structure of other exterior members of the endoscope  1 , and the connection structure of exterior members of the insertion apparatus other than the endoscope.