JP2004016337A - Actuator support structure for endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of an actuator by simple constitution in an endoscope comprising a small precise actuator for driving an optical member in an insertion part. <P>SOLUTION: A cylindrical actuator housing longer than an actuator assembly obtained by joining the actuator and a deceleration gear housing part coaxially is provided in the insertion part to house the actuator assembly in the actuator housing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
【Technical field】
The present invention relates to a support structure for an actuator for driving an optical member, which is provided at the distal end of an insertion section of an endoscope.
[0002]
[Prior art and its problems]
An endoscope that has a movable optical member at the distal end of an insertion section and performs zooming and focusing by driving the optical member by a motor (actuator) has been proposed. Although the diameter of the insertion portion of the endoscope varies, the motor housed at the distal end is an expensive micro motor having a diameter of several millimeters. In particular, this type of motor is handled as an assembly in which the motor body and the gear head (reduction gear housing) are joined in advance, and the joint between the motor body and the gear head and the connection between the motor body and the power supply lead wire. It is desired to ensure the durability of such parts.
[0003]
[Object of the invention]
An object of the present invention is to improve the durability around an actuator with a simple structure in an endoscope having an actuator for driving an optical member in an insertion portion.
[0004]
Summary of the Invention
According to the present invention, an actuator assembly formed by coaxially joining a cylindrical actuator and a reduction gear accommodating portion of the actuator is supported in an insertion portion, and an optical member constituting an objective optical system is driven by driving the actuator assembly. In an endoscope to be moved in the axial direction, a cylindrical actuator housing longer than the actuator assembly is provided in the insertion section, and the actuator assembly is housed in the actuator housing.
[0005]
In the actuator support structure of the present invention, it is preferable that the joint portion of the lead wire for supplying power to the actuator assembly is located in the actuator housing, and the adhesive is filled between the joint portion of the lead wire and the inner peripheral surface of the actuator housing.
[0006]
The cylindrical actuator housing can be provided, for example, parallel to the fixed cylinder centered on the optical axis of the objective optical system, eccentric from its axis. For example, when the optical member driven by the actuator is a movable lens group forming a part of the objective optical system and an imaging element provided at an image forming position of the objective optical system, the fixed cylinder provided with the actuator housing is movable. It is possible to provide a movable support tube that houses the holding frame for the lens group and the holding frame for the image sensor movably in the optical axis direction. Further, when the optical member driven by the actuator is only the movable lens group that forms a part of the objective optical system, the fixed cylinder provided with the actuator housing is provided at the image forming position of the objective optical system including the movable lens group. Can be used as a holding frame for the image sensor fixed to the image pickup device.
[0007]
The present invention also supports an actuator having a cylindrical shape as a whole having an actuator, a reduction gear accommodating portion of the actuator, and a lead wire joint to the actuator coaxially at the distal end of the insertion portion, and driving the actuator assembly. In an endoscope for moving an optical member constituting an objective optical system in the optical axis direction, the insertion section has a cylindrical shape substantially concentric with the actuator assembly, and the entire actuator assembly from the reduction gear storage section to the lead wire joint section. Is provided with an actuator housing long enough to accommodate the actuator housing.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An electronic endoscope 10 shown in FIG. 1 is a medical endoscope, and includes an insertion unit 11 inserted into a body cavity, and an operation unit 12 connected to a base side thereof and gripped and operated by an operator. I have. The insertion portion 11 has a tip portion 13, a bending portion 14, and a flexible tube portion 15 in this order from the tip side. The flexible tube portion 15 of the insertion portion 11 is flexible and flexible, and its base end is covered with a rubber stopper 16 to protect it from excessive deformation. When the endoscope is used, the buckle rubber 16 is not inserted into the body cavity. The bending section 14 can be bent by rotating a bending operation knob 17 provided on the operation section 12. A universal tube 18 extends laterally from the operation section 12, and a connector section 19 provided at the end of the universal tube 18 can be connected to an external processor (image processing apparatus) not shown. .
[0009]
As shown in FIG. 2, a light distribution lens 21 is fixed to a front end surface of a distal end rigid member 20 constituting the distal end portion 13, and the light exit end of a light guide fiber bundle 22 is fixed to the light distribution lens 21. Are facing each other. The light guide fiber bundle 22 is provided from the insertion portion 11 through the universal tube 18 to the connector portion 19, and distributes illumination light from a light source provided in the processor with the connector portion 19 connected to the processor. It can be guided to the lens 21. In the insertion portion 11, the light guide fiber bundle 22 is protected by a fiber protection coil 23 outside the light guide fiber bundle. The fiber protection coil 23 is fixed to the outer surface of the light guide fiber bundle 22.
[0010]
Further, in the distal end rigid member 20, the first lens group L1 fixed via the fixed lens frame 25 and the first lens group L1 are supported so as to be relatively movable in the optical axis direction from the object side. An objective optical system including the second lens unit L2 and the third lens unit L3 is provided. In the following description, the optical axis direction refers to the optical axis direction of the objective optical system.
[0011]
Behind the third lens group L3, an image sensor unit 26 movable in the optical axis direction is provided separately from the lens groups L2 and L3. The image pickup device unit 26 has a CCD (image pickup device) (not shown) and a buffer substrate built therein, and an image of an object to be observed by the objective optical system is formed on a light receiving surface of the CCD to generate an image signal. An image signal transmission cable 27 is connected to the rear end of the image sensor unit 26. The image signal transmission cable 27 has a structure in which a plurality of lead wires extending from the buffer substrate is covered with a tube made of polyurethane or the like, and is provided from the insertion portion 11 to the connector portion 19 via the universal tube 18. I have. The processor to which the connector unit 19 is connected can display an electronic image on a monitor or record the image on an image recording medium based on the image signal sent via the image signal transmission cable 27. A cover glass 28 is attached to the front surface of the image sensor unit 26.
[0012]
The electronic endoscope 10 changes the focal length of the objective optical system by moving the second and third lens groups L2 and L3 and the image sensor unit 26 in the optical axis direction, and relatively observes the observation field of view. It is possible to switch between a normal observation visual field having a wide range and a narrow enlarged observation visual field. The focal length switching (zoom) mechanism will be described.
[0013]
A cylindrical outer tube (fixed tube, movable support tube) 29 having a cylindrical shape centered on the optical axis of the objective optical system is fixed in the distal end rigid member 20. The fixed lens frame 25 described above is fitted to the front end of the outer tube 29, and the lens press ring 30 is fixed to the rear of the fixed lens frame 25. The position of the first lens unit L1 in the optical axis direction is determined by abutting on a flange formed on the lens holding ring 30. A rotation guide pin 31 protrudes from the lens press ring 30 in the outer diameter direction. The rotation guide pin 31 guides a rotation of a cam ring 32 rotatably supported inside the outer tube 29. It is engaged with the groove 33. The rotation guide groove 33 is formed in the circumferential direction around the optical axis of the objective optical system. Due to the relationship between the rotation guide groove 33 and the rotation guide pin 31, the cam ring 32 is moved in the optical axis direction. Is guided so as to be able to rotate only in the circumferential direction without moving.
[0014]
The cam ring 32 is formed with two different types of cam grooves 34 and 35. A cam pin 37 of a rectilinear frame 36 is engaged with the first cam groove 34. The rectilinear frame 36 is integrated with the image sensor frame 38, and the image sensor frame 38 is guided linearly in the optical axis direction of the objective optical system by a not-shown rectilinear guide formed on the inner peripheral surface of the outer tube 29. . A female screw 39 is formed in the imaging element frame 38, and a lead screw 41 formed on the outer peripheral surface of the screw shaft 40 is screwed to the female screw 39. The screw shaft 40 is rotated by a motor assembly (actuator assembly) 42. Therefore, when the screw shaft 40 is rotated in the normal or reverse direction by the motor assembly 42, the image sensor frame 38 advances and retreats in the optical axis direction due to the relationship between the lead screw 41 and the female screw 39, and the rectilinear frame 36 moves together with the image sensor frame 38. I do. The cam ring 32 is rotated via the cam pins 37 and the cam grooves 34 by the movement of the imaging element frame 38 and the rectilinear frame 36 in the optical axis direction. The operation of the motor is operated by an operation switch 43 provided on the operation unit 12.
[0015]
The image sensor unit 26 is fixed inside the image sensor frame 38, and the image sensor unit 26 moves in the optical axis direction integrally with the image sensor frame 38. Specifically, the outside of the image pickup device unit 26 is covered with a shield pipe 44 for ground, and the outside thereof is further covered with an insulating tape 45, and the image pickup device frame 38 is fitted outside the insulating tape 45.
[0016]
The cam pin 51 of the movable lens group frame 50 that holds the second and third lens groups L2 and L3 is engaged with the second cam groove 35 formed in the cam ring 32. The cam pin 51 has a distal end engaged with the cam groove 35, and a region closer to the proximal end than the distal end engaged with a rectilinear guide slot 52 formed in the rectilinear frame 36 in the optical axis direction. The movable lens group frame 50 is guided linearly in the optical axis direction due to the engagement relationship between 51 and the linear guide slot 52. The cam groove 35 is a cam groove that is inclined with respect to the optical axis. When the cam ring 32 rotates, the movable lens group frame 50 moves in the optical axis direction due to the relationship between the cam groove 35 and the cam pin 51. That is, the second and third lens groups L2 and L3 held by the movable lens group frame 50 move in the optical axis direction. A compression coil spring 53 for removing backlash is provided between the front end surface of the movable lens group frame 50 and the lens holding ring 30, and the movable lens group frame 50 is urged rearward in the optical axis direction.
[0017]
The above focal length switching mechanism operates as follows. FIG. 2 shows a normal observation visual field state. When the enlarged observation visual field position is selected by the operation switch 43 from this state, the screw shaft 40 is rotated by the motor assembly 42, and the image sensor frame 38 and the rectilinear frame 36 holding the image sensor unit 26 move backward in the optical axis direction. . The rearward movement of the image sensor frame 38 and the rectilinear frame 36 causes the cam ring 32 to rotate due to the relationship between the cam groove 34 and the cam pin 37. When the cam ring 32 rotates, the movable lens group frame 50 holding the second and third lens groups L2 and L3 moves forward in the optical axis direction due to the relationship between the cam groove 35 and the cam pin 51. That is, when switching from the normal observation visual field to the enlarged observation visual field, the second and third movable lens groups L2 and L3 approach the first lens group L1 that does not move, and the image sensor unit 26 is separated rearward. At the time of switching from the enlarged observation visual field to the normal observation visual field, the focal length switching mechanism operates in the reverse manner. That is, when the operation switch 43 is operated, the screw shaft 40 is rotated in the reverse direction by the motor, and the image sensor frame 38 and the rectilinear frame 36 move forward in the optical axis direction and return to the position shown in FIG. At the same time, in response to the movement of the image sensor frame 38 and the rectilinear frame 36, the cam ring 32 rotates in the opposite direction to that when switching to the enlarged observation field, and the movable lens group frame 50 moves backward in the optical axis direction. Return to the position of FIG.
[0018]
The motor assembly 42, which is the drive source of the above focal length switching mechanism, includes a gear head (reduction gear housing) 55 into which the base end of the screw shaft 40 is inserted, and a motor body (actuator) having substantially the same diameter as the gear head 55. A motor terminal 57 (lead wire joint) to which a power supply lead wire 58 is connected protrudes from the rear end of the motor main body 56. A reduction gear train (not shown) is provided in the gear head 55, and transmits the driving force of the motor to the screw shaft 40 protruding from the gear head 55 via the reduction gear train. Further, a lead wire 58 is soldered to the motor terminal 57. The lead wire 58 is housed in a motor drive cable (actuator drive cable) 60 and is connected to a power supply circuit (not shown). When the operation switch 43 is operated, the lead wire 58 is connected to the motor body via the lead wire 58. Drive power is supplied to 56.
[0019]
As shown in FIG. 2, the motor assembly 42 is housed in a cylindrical motor housing (actuator housing) 61 concentric with the motor assembly 42. The motor housing 61 is formed on a housing member 62 whose unit shape is shown in FIG. The housing member 62 has a detachable ring portion 63 fitted to the rear end of the outer tube 29 that houses the above-described focal length switching mechanism. The motor housing 61 is eccentric from the center of the detachable ring portion 63. It is protruded at the position. A circular hole 64 through which the image signal transmission cable 27 is inserted is formed at the center of the attachment / detachment ring 63. The housing member 62 can be fixed to the outer tube 29 by engaging a fixing rivet 66 (FIG. 2) with a rivet hole 65 formed in the detachable ring portion 63. A screw or the like may be used as a means for fixing the outer cylinder 35 and the housing member 62. Since the outer cylinder tube 29 is fixed to the distal end rigid member 20, by fixing the outer cylinder tube 29 to the outer cylinder tube 29, the housing member 62, that is, the motor housing 61 becomes a fixing member at the distal end of the insertion portion.
[0020]
At the time of assembly, the motor assembly 42 is inserted into the motor housing 61 with the gear head 55 side first, and when a predetermined amount is inserted, the end of the gear head 55 contacts the insertion positioning step 67 formed inside the motor housing 61. Touch The inner diameter of the motor housing 61 is smaller than the outer diameter of the motor assembly 42 in front of the insertion positioning step 67 (the left-hand direction in FIG. 2), and the insertion of the motor assembly 42 is restricted. The motor housing 61 is formed to be longer in the axial direction than the motor assembly 42, and at the time of this insertion restriction, the motor assembly 42 is moved from the front end side gear head 55 to the rear end side motor terminal 57 (connection portion of the lead wire 58). Up to that point, almost the entirety is stored in the motor housing 61. The screw shaft 40 projects forward through a shaft insertion hole 68 formed at the front end of the motor housing 61, and screwes the lead screw 41 to the female screw 39. Subsequently, an adhesive 59 is filled around the soldered motor terminals 57 and lead wires 58, and the motor housing 61, the motor assembly 42, and the motor drive cable 60 are fixed. At this time, since the motor housing 61 surrounds the vicinity of the lead wire joint, the adhesive 59 is unlikely to leak to the outside, and the bonding operation can be easily performed.
[0021]
In the motor support structure described above, since the entire motor assembly 42 is covered and protected by the motor housing 61, the possibility that the motor assembly 42, which is an expensive precision component, is damaged due to a load is reduced. For example, when the bending portion 14 is bent or the flexible tube portion 15 is bent, the motor drive cable 60 passing through the inside thereof is pushed and pulled. Here, since the entire motor assembly 42 is housed and fixed so as to be integrated with the motor housing 61, the push-pull force acting on the motor drive cable 60 is applied to the housing member 62 having the motor housing 61, and A larger fixing member is received by the outer tube 29 to which the housing member 62 is fixed, so that no excessive load is applied to the motor assembly 42. Therefore, it is possible to prevent breakage of a portion such as a joint between the gear head 55 and the motor body 56 and a connection between the motor drive cable 60 and the motor assembly 42.
[0022]
FIG. 4 shows a second embodiment of the motor support structure according to the present invention. FIG. 4 shows only the main part of the objective optical system and the focal length switching mechanism at the distal end of the insertion section, and does not show other members. In the endoscope of this embodiment, a fixed lens frame 70 that supports the first lens unit L1, a connection tube 71 and a straight guide tube 72 inside the fixed lens frame 70, and an image sensor frame (fixed tube) that fits into the rear end of the connection tube 71 ) 73, fixed lens frames 74 that are located between the imaging element frame 73 and the straight guide cylinder 72 and that support the fourth lens unit L4 are fixing members at the distal end of the insertion portion.
[0023]
A cam ring 75 is rotatably fitted around the optical axis between the connection cylinder 71 and the straight guide cylinder 72. The two lens grooves L a and 75 b of the cam ring 75 are The cam pins 78 and 79 of the movable lens frames 76 and 77 that hold the third lens group L3 are engaged. The regions on the base end side of the cam pins 78 and 79 are guided in the optical axis direction by a linear guide slot formed in the linear guide tube 72 in the optical axis direction. A gear 75c is formed on the outer peripheral surface of the rear end portion of the cam ring 75, and a motor shaft gear 83 extended from a motor assembly 82 described later meshes with the gear 75c. Accordingly, the cam ring 75 is rotated by driving the motor, and when the cam ring 75 is rotated, the second lens unit L2 and the third lens unit L3 move straight in the optical axis direction according to the shape of the cam groove, and the zooming operation is performed. .
[0024]
The image sensor frame 73 which has a single shape in FIG. 5 includes two cylindrical portions, an image sensor housing cylinder portion 81 for housing the image sensor unit 80 and a large-diameter motor housing portion (actuator housing) 84 for housing the motor assembly 82. And a small-diameter motor housing (actuator housing) 85 that can be inserted into and removed from the large-diameter motor housing 84 as a separate member.
[0025]
The motor assembly 86 has a large-diameter gear head (reduction gear housing) 87 corresponding to the inner diameter of the large-diameter motor housing portion 84 and is joined to the rear end of the gear head 87 to correspond to the inner diameter of the small-diameter motor housing portion 85. And a motor body 88 having a small diameter. An insertion positioning step 89 is formed in the large-diameter motor housing section 84, and the motor assembly 86 can be inserted until the gear head 87 comes into contact with the insertion positioning step 89. At the time of the insertion restriction, the motor shaft gear 83 meshes with the gear 75c of the cam ring 75. Subsequently, when the small-diameter motor housing portion 85 is inserted into the large-diameter motor housing portion 84, the motor body 88 and the connection portion between the motor terminal 90 and the lead wire 91 on the rear end side are covered by the small-diameter motor housing portion 85. . Further, by filling the inside of the opening of the small-diameter motor housing portion 85 with the adhesive 92, the motor drive cable 93 containing the lead wire 91 and the motor assembly 86 are fixed to the small-diameter motor housing portion 85. .
[0026]
In the above-described second embodiment, the entire motor assembly 86 is housed and fixed in a cylindrical motor housing including the first and second motor housing portions 84 and 85. Therefore, similarly to the first embodiment, a load applied when the motor drive cable 93 is pushed or pulled is received by the image sensor frame 73, and no load is applied to the motor assembly 86. Therefore, damage to the joint between the gear head 87 and the motor main body 88 and the joint between the motor assembly 86 and the motor drive cable 93 in the motor assembly 86 can be prevented.
[0027]
Although the illustrated embodiment has been described as a support structure for a motor that rotates a drive shaft, the present invention is also applicable to a support structure for an actuator other than such a type of motor.
[0028]
【The invention's effect】
As is clear from the above, according to the actuator support structure of the present invention, the durability around the small precision actuator provided inside the distal end of the insertion portion can be improved with a simple structure.
[Brief description of the drawings]
FIG. 1 is an external view of an endoscope to which an actuator support structure of the present invention is applied.
FIG. 2 is a cross-sectional view of the vicinity of a distal end of an insertion portion of the endoscope of FIG.
FIG. 3 is a single perspective view of a housing member having a motor housing provided inside a distal end of an insertion portion in FIG. 2;
FIG. 4 is a cross-sectional view of the vicinity of a distal end of an insertion portion according to a second embodiment of the present invention.
5 is an exploded perspective view showing an image sensor frame having a large-diameter motor housing portion and a small-diameter motor housing portion provided in the distal end of the insertion portion in FIG. 4;
[Explanation of symbols]
REFERENCE SIGNS LIST 10 electronic endoscope 11 insertion section 12 operation section 13 distal end section 14 bending section 15 flexible tube section 17 bending operation knob 26 imaging element unit 29 outer tube (fixed tube, movable support tube)
32 Cam ring 36 Linear frame 38 Image sensor frame 40 Screw shaft 42 Motor assembly (actuator assembly)
50 Movable lens group frame 55 Gear head (reduction gear storage section)
56 Motor body (actuator)
57 Motor terminal 58 Lead wire 60 Motor drive cable (actuator drive cable)
61 Motor housing (actuator housing)
62 Housing member 63 Removable ring part 67 Insertion positioning step part 71 Connection cylinder 72 Straight guide cylinder 73 Image sensor frame (fixed cylinder)
75 Cam ring 80 Image sensor unit 81 Image sensor storage cylinder 82 Motor assembly (actuator assembly)
83 Motor shaft gear 84 Large diameter motor housing (actuator housing)
85 Small diameter motor housing (actuator housing)
87 Gear head (reduction gear storage section)
88 Motor body (actuator)
89 Insertion positioning step 90 Motor terminal 91 Lead wire 92 Adhesive 93 Motor drive cable L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group

Claims (7)

An actuator assembly formed by coaxially joining a cylindrical actuator and a reduction gear accommodating portion of the actuator is supported in the insertion portion, and the optical member constituting the objective optical system is moved in the optical axis direction by driving the actuator assembly. Endoscope
An actuator support structure for an endoscope, wherein a cylindrical actuator housing longer than an actuator assembly is provided in an insertion portion, and the actuator assembly is housed in the actuator housing. 2. The endoscope according to claim 1, wherein a joint of a lead wire connected to the actuator is located in the actuator housing, and an adhesive is filled between the joint of the lead wire and an inner peripheral surface of the actuator housing. Mirror actuator support structure. 3. The actuator support structure according to claim 1, further comprising: a fixed cylinder centered on an optical axis of the objective optical system in the insertion portion, wherein the actuator housing is provided at a position eccentric to an axis of the fixed cylinder. An endoscope actuator support structure provided in parallel with the endoscope. 4. The actuator support structure according to claim 3, wherein the optical member driven by the actuator assembly is a movable lens group forming a part of the objective optical system, and an image sensor provided at an image forming position of the objective optical system.
The actuator support structure for an endoscope, wherein the fixed cylinder is a movable support cylinder that accommodates the holding frame for the movable lens group and the holding frame for the image sensor so as to be movable in the optical axis direction. 4. The actuator supporting structure according to claim 3, wherein the optical member driven by the actuator assembly is a movable lens group forming a part of an objective optical system,
An actuator support structure, wherein the fixed cylinder is a holding frame of an image sensor fixed to an image forming position of an objective optical system including the movable lens group. An overall cylindrical actuator assembly having an actuator, a reduction gear accommodating portion of the actuator, and a lead wire connecting portion to the actuator on the same axis is supported in the insertion portion, and the objective optical system is configured by driving the actuator assembly. In an endoscope that moves an optical member to be moved in the optical axis direction,
An endoscope having a cylindrical shape substantially concentric with the actuator assembly in the insertion portion and having an actuator housing long enough to house the entire actuator assembly from the reduction gear housing to the lead wire joint. Actuator support structure. 7. The actuator support structure of an endoscope according to claim 6, wherein an adhesive is filled between the lead wire joint and an inner peripheral surface of the actuator housing.

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