JP2010088643A - Remote control type actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remote control type actuator in which the posture of a tool provided on the distal end of an elongate pipe part can be changed by remote control and the rigidity of the pipe part is high. <P>SOLUTION: The remote control type actuator includes a spindle guide part 3 in an elongate shape as the pipe part, a distal end member 2 attached to the distal end so as to freely change the posture, and a drive part housing to which the proximal end of the spindle guide part 3 is connected. The distal end member 2 freely rotatably supports a spindle 13 holding the tool 1. The spindle guide part 3 has a shell pipe 25, a rotary shaft 22 and a guide pipe 30, and a posture operating member 31 for changing the posture of the distal end member 2 is inserted into the guide pipe 30. The hollow hole 24 of the shell pipe 25 comprises a circular hole part 24a at the center part and a groove-like part 24b recessed from the circular hole part 24a to the outer diameter side. The rotary shaft 22 is disposed to the circular hole part 24a and the guide pipe 30 is disposed to the groove-like part 24b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a remotely operated actuator that can change the posture of a tool by remote operation and is used for medical use, machining, and the like.

  There are remote-operated actuators that are used for bone processing for medical purposes and drilling and cutting for mechanical processing. The remote operation type actuator remotely controls a tool provided at the end of a long and narrow pipe portion having a linear shape or a curved shape. However, since the conventional remote control actuator only controls the rotation of the tool by remote control, in the case of medical use, it was difficult to process a complicated shape or a part that is difficult to see from the outside. Further, in drilling, it is required that not only a straight line but also a curved shape can be processed. Furthermore, in the cutting process, it is required that a deep part inside the groove can be processed. Hereinafter, taking the medical use as an example, the prior art and problems of the remote control type actuator will be described.

  In the field of orthopedics, there is an artificial joint replacement operation in which a joint that has become worn out due to bone aging or the like is replaced with a new artificial one. In this operation, it is necessary to process the patient's living bone so that the artificial joint can be inserted. In order to increase the adhesive strength between the living bone and the artificial joint after the operation, the shape of the artificial joint is required. It is required to process with high accuracy.

  For example, in hip joint replacement surgery, an artificial joint insertion hole is formed in the medullary cavity at the center of the femur bone. In order to maintain the contact strength between the artificial joint and the bone, it is necessary to increase the contact area between them, and the hole for inserting the artificial joint is processed into an elongated shape extending to the back of the bone. As a medical actuator used for such a bone cutting process, a tool is rotatably provided at the distal end of an elongated pipe portion, and by driving a rotational drive source such as a motor provided on the proximal end side of the pipe portion, There exists a thing of the structure which rotates a tool via the rotating shaft arrange | positioned inside (for example, patent document 1). In this type of medical actuator, the rotating part exposed to the outside is only the tool at the tip, so that the tool can be inserted deep into the bone.

Artificial joint replacement surgery involves skin incision and muscle cutting. That is, the human body must be damaged. In order to minimize the scratches, the pipe part may not be straight but may be appropriately curved. In order to cope with such a situation, there are the following conventional techniques. For example, in Patent Document 2, an intermediate portion of a pipe portion is bent twice, and the axial center position on the distal end side and the axial center position on the proximal end side of the pipe portion are shifted. There are other known cases where the axial position of the pipe portion is shifted between the tip end side and the axial center side. In Patent Document 3, the pipe portion is rotated 180 degrees.
JP 2007-301149 A U.S. Pat. No. 4,466,429 US Pat. No. 4,265,231 JP 2001-17446 A

  If there is a wide gap between the living bone and the artificial joint with the artificial joint inserted in the artificial bone insertion hole of the living bone, the adhesion time after the operation becomes longer, so the gap is as narrow as possible. desirable. It is also important that the contact surface between the living bone and the artificial joint is smooth, and high accuracy is required for processing the hole for inserting the artificial joint. However, no matter what the shape of the pipe part, the operating range of the tool is limited by the shape of the pipe part. It is difficult to process the artificial joint insertion hole so that the gap is narrow and the contact surface of both is smooth.

  Generally, bones of patients undergoing artificial joint replacement surgery are often weakened due to aging or the like, and the bones themselves may be deformed. Therefore, it is more difficult to process the artificial joint insertion hole than is normally conceivable.

  Therefore, the present applicant tried to make it possible to change the posture of the tool by remote operation in order to make it possible to process the artificial joint insertion hole relatively easily and accurately. This is because, if the posture of the tool can be changed, the tool can be held in an appropriate posture regardless of the shape of the pipe portion. However, since the tool is provided at the tip of the elongated pipe portion, there are many restrictions in providing a mechanism for changing the posture of the tool, and a device for overcoming it is necessary. Note that some medical actuators that do not have an elongated pipe part can change the position of the part where the tool is provided relative to the hand-held part (for example, Patent Document 4), but the position of the tool can be changed remotely. Nothing has been proposed to make it happen.

  In a remote control type actuator in which a tool is provided at the tip of an elongated pipe portion, when an external force is applied to the tool or the like, it is conceivable that the position of the tool is shifted due to the bending of the elongated pipe portion. If the position of the tool is shifted, accurate machining and accurate tool posture control cannot be performed. In addition, if the pipe portion is easily bent, the cutting force is less likely to act perpendicularly on the workpiece, resulting in poor machinability. For these reasons, the pipe portion is required to have sufficient rigidity.

  The present invention provides a remotely operated actuator that can change the posture of a tool provided at the tip of an elongated pipe portion by remote control, has a high rigidity of a spindle guide portion as a pipe portion, and has good assemblability. It is an issue.

  A remote-control actuator according to the present invention includes an elongated spindle guide portion, a tip member attached to the tip of the spindle guide portion via a tip member connecting portion so that the posture can be freely changed, and a base end of the spindle guide portion And a drive unit housing coupled thereto, the tip member rotatably supporting a spindle for holding a tool, the spindle guide unit including a hollow outer pipe serving as an outer shell of the spindle guide portion, and the outer shell. A rotating shaft that is provided in a hollow hole that penetrates both ends of the pipe and transmits the rotation of a driving source for tool rotation in the drive unit housing to the spindle, and a hollow guide pipe that is provided in the hollow hole and penetrates both ends And a guide for a posture operation member that changes the posture of the tip member by advancing and retracting with the tip contacting the tip member. An attitude change drive source is provided in the drive section housing for allowing the attitude control member to be advanced and retracted in the interior of the drive, and the hollow hole has a circular hole at the center and an outer diameter from the circular hole. The rotary shaft is disposed in the circular hole portion, and the guide pipe is disposed in the groove portion.

  According to this structure, cutting of a bone etc. is performed by rotation of the tool provided in the tip member. In this case, when the posture operation member is moved forward and backward by the posture change drive source, the tip of the posture operation member acts on the tip member, so that the posture can be changed to the tip of the spindle guide portion via the tip member connecting portion. The position of the tip member attached to is changed. The posture changing drive source is provided in the drive portion housing on the proximal end side of the spindle guide portion, and the posture change of the tip member is performed by remote control. Since the posture operation member is inserted into the hollow guide pipe, the posture operation member does not shift in the direction intersecting the longitudinal direction, and can always act properly on the tip member. The posture changing operation is performed accurately.

  Since the hollow hole of the outer pipe is composed of a circular hole at the center and a groove-like part recessed from the circular hole to the outer diameter side, the thickness of the portion other than the groove-like part of the outer pipe should be increased. Can do. As a result, the rigidity of the spindle guide portion (secondary moment of section) is increased, the positioning accuracy of the tip member is improved, and the machinability is improved. For example, the cross-sectional secondary moment of the outer pipe is ½ or more of the solid shaft with the same outer diameter. Further, since the guide pipe is arranged in the groove-like portion, the guide pipe can be easily positioned in the circumferential direction, and the assemblability is good.

In this invention, the posture operation member may be composed of a plurality of force transmission members arranged in a line along the length direction of the guide pipe, or a wire along the length direction of the guide pipe. it can.
In either case, the posture operation member can be advanced and retracted by the posture change drive source. Further, the posture operation member is flexible as a whole, and can follow the bending of the spindle guide portion.

  In the present invention, the guide pipe and the posture operation member inserted into the guide pipe are provided in only one place, a restoring elastic member for urging the tip member toward a predetermined posture is provided, and the posture operation member is The posture of the tip member can be changed against the biasing force of the restoring elastic member. Further, the guide pipe and the posture operation member inserted into the guide pipe are provided at two locations, the posture change drive source is individually provided for each posture operation member, and the posture control members of the two locations are provided. You may change and maintain the attitude | position of the said front-end | tip member by the balance of the acting force to a front-end | tip member. In these cases, the posture of the tip member can be changed around one posture changing axis. In the latter, since the tip member is pressurized by two posture operation members, the posture stability of the tip member can be improved as compared with the former in which pressure is applied by only one posture operation member.

  Further, the tip member connecting portion supports the tip member so as to be tiltable in an arbitrary direction, and the guide pipe and the posture operation member inserted into the guide pipe are arranged around the tilt center of the tip member. The posture changing drive source is provided individually for each posture operation member, and the posture of the tip member is adjusted by balancing the acting forces of the posture operation members of the three or more locations on the tip member. It may be changed and maintained. In this case, the posture of the tip member can be changed around the two posture change axes. In this configuration, since the tip member is pressurized by three or more posture operation members, the posture stability of the tip member can be further improved.

In the present invention, when a plurality of rolling bearings that rotatably support the rotating shaft in the spindle guide portion are provided, it is desirable to provide a spring element that applies a preload to the rolling bearings between adjacent rolling bearings.
In order to improve the finish of processing, it is preferable to rotate the spindle at high speed. When the spindle is rotated at a high speed, there is an effect of reducing cutting resistance acting on the tool. Since the rotational force is transmitted to the spindle through a thin rotating shaft made of a wire or the like, it is necessary to preload the rolling bearing that supports the rotating shaft in order to realize high-speed rotation of the spindle. If a spring element for this preload is provided between adjacent rolling bearings, the spring element can be provided without increasing the diameter of the spindle guide portion.

Moreover, when the rolling bearing which supports the said rotating shaft in the said spindle guide part rotatably is provided, the outer diameter surface of this rolling bearing can be supported by the said guide pipe.
By using the guide pipe, the outer diameter surface of the rolling bearing can be supported without using an extra member.

In the case of providing a bearing that rotatably supports the rotating shaft in the spindle guide portion, a cooling unit that cools the bearing with a coolant that passes through the inside of the outer pipe may be provided.
Rotating members such as a spindle and a rotating shaft that rotate the tool generate heat due to rotational friction. Along with this, the bearing is heated. If a cooling means is provided, a bearing and the said heat_generation | fever location can be cooled with a cooling fluid. If the coolant is allowed to pass through the outer pipe, there is no need to provide a separate coolant supply pipe, and the spindle guide portion can be simplified and reduced in diameter.
Furthermore, the effect of lubricating the bearing with the coolant is also obtained. If the coolant is also used for the lubrication of the bearing, it is not necessary to use grease or the like generally used for the bearing, and it is not necessary to provide a separate lubricating device.

Moreover, you may provide the cooling means which cools the said tool with the cooling fluid which passes through the inside of the said outer pipe, or the cooling fluid supplied from the outside.
At the time of processing, the tool and the work piece generate heat. If the cooling means is provided, the tool and the workpiece can be cooled by the coolant.

In the present invention, a pipe fixing portion that fixes the outer pipe and the guide pipe may be provided.
Since the outer pipe and the guide pipe are fixed by the pipe fixing portion, the rigidity of the spindle guide portion is further enhanced.

The pipe fixing portion may be configured such that an opening communicating with the inside and the outside is provided in a peripheral wall of the outer pipe, and the periphery of the opening in the outer pipe and the guide pipe are fixed by brazing or welding. Alternatively, the pipe fixing portion may be configured to fix the outer pipe and the guide pipe by laser welding from the outer diameter surface side of the outer pipe.
In any case, the outer pipe and the guide pipe can be fixed relatively easily and firmly. In particular, since the latter does not require an opening in the outer pipe compared to the former, the rigidity of the spindle guide portion can be further increased and the assemblability is improved.

In the present invention, the spindle guide portion may have a curved portion.
Since the posture operation member is flexible, even if there is a curved portion in the spindle guide portion, it can be advanced and retracted in the guide hole.

  The remote control type actuator according to the present invention comprises an elongated spindle guide portion, a tip member attached to the tip of the spindle guide portion via a tip member connecting portion so that the posture can be freely changed, and a base end of the spindle guide portion. A drive housing that is coupled, the tip member rotatably supports a spindle that holds a tool, the spindle guide portion is a hollow outer pipe that is an outer shell of the spindle guide portion, and the outer pipe A rotating shaft that is provided in a hollow hole that penetrates both ends of the tool and transmits the rotation of a drive source for rotating the tool in the drive unit housing to the spindle, and a hollow guide pipe that is provided in the hollow hole and penetrates both ends. An attitude control member that changes the attitude of the tip member by moving forward and backward with the tip contacting the tip member. A posture changing drive source is provided in the drive unit housing to be inserted into and retracted freely and the posture operating member is moved forward and backward. The hollow hole has a central circular hole and an outer diameter side from the circular hole. Since the rotary shaft is disposed in the circular hole portion and the guide pipe is disposed in the groove portion, the posture of the tool provided at the tip of the elongated pipe portion can be remotely controlled. It can be changed, the rigidity of the spindle guide portion as the pipe portion is high, and the assemblability is good.

  An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, the remote control type actuator includes a tip member 2 for holding a rotary tool 1, an elongated spindle guide portion 3 having the tip member 2 attached to the tip so that the posture can be freely changed, and the spindle guide. A drive unit housing 4a to which the base end of the unit 3 is coupled, and a controller 5 for controlling the tool rotation drive mechanism 4b and the attitude change drive mechanism 4c in the drive unit housing 4a are provided. The drive unit housing 4a constitutes the drive unit 4 together with the built-in tool rotation drive mechanism 4b and posture changing drive mechanism 4c.

  As shown in FIG. 2, the tip member 2 has a spindle 13 rotatably supported by a pair of bearings 12 inside a substantially cylindrical housing 11. The spindle 13 has a cylindrical shape with an open end, and the shank 1a of the tool 1 is inserted into the hollow portion in a fitted state, and the shank 1a is non-rotatably coupled by the rotation prevention pin 14. The tip member 2 is attached to the tip of the spindle guide portion 3 via the tip member connecting portion 15. The tip member connecting portion 15 is a means for supporting the tip member 2 so that the posture thereof can be freely changed, and includes a spherical bearing. Specifically, the distal end member connecting portion 15 includes a guided portion 11 a that is a reduced inner diameter portion of the proximal end of the housing 11 and a hook-shaped portion of a retaining member 21 that is fixed to the distal end of the spindle guide portion 3. It is comprised with the guide part 21a. The guide surfaces F1 and F2 that are in contact with each other 11a and 21a are spherical surfaces having a center of curvature O located on the center line CL of the spindle 13 and having a smaller diameter toward the proximal end side. As a result, the tip member 2 is prevented from being detached from the spindle guide portion 3 and is supported so as to be freely changeable in posture. In this example, since the tip member 2 is configured to change the posture around the X axis passing through the center of curvature O, the guide surfaces F1 and F2 may be cylindrical surfaces having the X axis passing through the point O as an axis. .

  The spindle guide portion 3 has a rotating shaft 22 that transmits the rotational force of the tool rotation drive source 41 (FIG. 3) in the drive portion housing 4 a to the spindle 13. In this example, the rotating shaft 22 is a wire and can be elastically deformed to some extent. As the material of the wire, for example, metal, resin, glass fiber or the like is used. The wire may be a single wire or a stranded wire. As shown in FIG. 2C, the spindle 13 and the rotary shaft 22 are connected so as to be able to transmit rotation via a joint 23 such as a universal joint. The joint 23 includes a groove 13 a provided at the closed base end of the spindle 13 and a protrusion 22 a provided at the distal end of the rotating shaft 22 and engaged with the groove 13 a. The center of the connecting portion between the groove 13a and the protrusion 22a is at the same position as the center of curvature O of the guide surfaces F1 and F2. The rotating shaft 22 and the protrusion 22a may be configured as separate members.

The spindle guide portion 3 has an outer pipe 25 that is an outer portion of the spindle guide portion 3. The outer pipe 25 has a hollow shape penetrating at both ends, and the hollow hole 24 extends from the circular hole portion 24a at the center portion to the outer diameter side from a circumferential position that forms a phase of 180 degrees on the outer periphery of the circular hole portion 24a. It consists of two recessed grooves 24b. The peripheral wall at the tip of the groove-like portion 24b has a semicircular cross section. For example, the outer diameter of the outer pipe 25 is 8 to 10 mm, and the inner diameter of portions other than the groove-like portion 24 is 3 to 5 mm. Further, as the material of the outer pipe 25, stainless steel, titanium or the like is suitable.
By making the outer pipe 25 have the above-described cross-sectional shape, the thickness t of the outer pipe 25 other than the groove-like portion 24b can be increased. Thereby, the cross-sectional secondary moment of the outer pipe 25 can be set to 1/2 or more of the solid shaft with the same outer diameter. For example, in the case of a solid shaft made of stainless steel and having an outer diameter of 8 mm, the secondary moment of section is about 200 mm ⁴ .

  The rotary shaft 22 is disposed in the circular hole portion 24 a of the hollow hole 24. The rotating shaft 22 is rotatably supported by a plurality of rolling bearings 26 that are arranged apart from each other in the axial direction. Between each rolling bearing 26, spring elements 27A and 27B for generating a preload on the rolling bearing 26 are provided. The spring elements 27A and 27B are, for example, compression coil springs. There are an inner ring spring element 27A for generating a preload on the inner ring of the rolling bearing 26 and an outer ring spring element 27B for generating a preload on the outer ring, which are arranged alternately. The retaining member 21 is fixed to the pipe end portion 25a of the outer pipe 25 by a fixing pin 28, and rotatably supports the distal end portion of the rotary shaft 22 via a rolling bearing 29 at the distal end inner peripheral portion thereof. The pipe end portion 25a may be a separate member from the outer pipe 25 and may be joined by welding or the like.

  One of the hollow holes 24 (upper side in FIG. 2) is provided with a hollow guide pipe 30 penetrating at both ends. And the attitude | position operation member 31 is penetrated by the guide hole 30a which is an internal diameter hole of this guide pipe 30 so that advance / retreat is possible. In this example, the posture operation member 31 is a wire. The distal end of the posture operation member 31 is spherical, and the spherical distal end is in contact with the bottom surface of the radial groove portion 11 b formed on the base end surface of the housing 11. The groove 11b and the posture operation member 31 constitute an anti-rotation mechanism 37, and the tip member 2 inserted into the groove 11b hits the side surface of the groove 11b, so that the tip member 2 is in front of the spindle guide 3. Rotation around the center line CL of the member 2 is prevented.

  For example, compression is provided between the proximal end surface of the housing 11 of the distal end member 2 and the distal end surface of the outer pipe 25 of the spindle guide portion 3 at a position 180 degrees relative to the circumferential position where the posture operation member 31 is located. A restoring elastic member 32 made of a coil spring is provided. The restoring elastic member 32 acts to urge the tip member 2 toward a predetermined posture.

  A solid reinforcing shaft 34 is disposed in the groove portion 24b on the other side (lower side in FIG. 2) of the hollow hole 24. The reinforcing shaft 34 is for ensuring the rigidity of the spindle guide portion 3. The guide pipe 30 and the reinforcing shaft 34 are located on the same pitch circle C, and the guide pipe 30 and the reinforcing shaft 34 support the outer diameter surface of the rolling bearing 26.

  FIG. 3 shows a tool rotation drive mechanism 4b and a posture change drive mechanism 4c in the drive unit housing 4a. The tool rotation drive mechanism 4 b includes a tool rotation drive source 41 controlled by the controller 5. The tool rotation drive source 41 is, for example, an electric motor, and its output shaft 41 a is coupled to the proximal end of the rotation shaft 22. The posture changing drive mechanism 4 c includes a posture changing drive source 42 controlled by the controller 5. The posture changing drive source 42 is, for example, an electric linear actuator, and the movement of the output rod 42 a that moves in the left-right direction in FIG. 3A is transmitted to the posture operating member 31 through the force transmission mechanism 43. The boost transmission mechanism 43 has a lever 43b that is rotatable around a support shaft 43a. The force of the output rod 42a acts on an action point P1 of the lever 43b that is long from the support shaft 43a. The force is applied to the posture operation member 31 at the force point P <b> 2 having a short distance, and the output of the posture changing drive source 42 is increased and transmitted to the posture operation member 31. If the boost transmission mechanism 43 is provided, a large force can be applied to the posture operation member 31 even with a linear actuator having a small output, and thus the linear actuator can be downsized. The rotary shaft 22 passes through an opening 44 formed in the lever 43b. Instead of providing a linear actuator or the like, the posture of the tip member 2 may be remotely operated manually.

  The posture change drive mechanism 4c is provided with an operation amount detector 45 for detecting the operation amount of the posture change drive source 42. The detection value of the movement amount detector 45 is output to the posture detection means 46. The posture detection means 46 detects the tilt posture of the tip member 2 around the X axis (FIG. 2) based on the output of the movement amount detector 45. The posture detection means 46 has relationship setting means (not shown) in which the relationship between the tilt posture and the output signal of the motion amount detector 45 is set by an arithmetic expression or a table, and the relationship is determined from the input output signal. The tilting posture is detected using setting means. This posture detection means 46 may be provided in the controller 5 or may be provided in an external control device.

  The posture changing drive mechanism 4c is provided with a wattmeter 47 that detects the amount of power supplied to the posture changing drive source 42, which is an electric actuator. The detected value of the supplied wattmeter 47 is output to the load detecting means 48. The load detection means 48 detects the load acting on the tip member 2 based on the output of the wattmeter 47. The load detection means 48 has relation setting means (not shown) in which the relation between the load and the output signal of the supplied wattmeter 47 is set by an arithmetic expression or a table, and the relation setting means is determined from the input output signal. The load is detected using. The load detecting means 48 may be provided in the controller 5 or may be provided in an external control device.

  The controller 5 controls the tool rotation drive source 41 and the posture change drive source 42 based on the detection values of the posture detection means 46 and the load detection means 48.

The operation of this remote control type actuator will be described.
When the tool rotation drive source 41 is driven, the rotational force is transmitted to the spindle 13 via the rotation shaft 22, and the tool 1 rotates together with the spindle 13. The load acting on the tip member 2 when the tool 1 is rotated to cut bone or the like is detected by the load detection means 48 from the detection value of the supply wattmeter 47. By controlling the feed amount of the entire remote operation type actuator and the posture change of the distal end member 2 described later according to the load value thus detected, the load acting on the distal end member 2 can be appropriately maintained while maintaining the load. Cutting can be performed.

  At the time of use, the posture changing drive source 42 is driven to change the posture of the tip member 2 by remote control. For example, when the posture operating member 31 is advanced to the distal end side by the posture changing drive source 42, the housing 11 of the distal end member 2 is pushed by the posture operating member 31, and the distal end member 2 is directed downward in FIG. The posture is changed along the guide surfaces F1 and F2 toward the side. On the other hand, when the posture operation member 31 is retracted by the posture changing drive source 42, the housing 11 of the tip member 2 is pushed back by the elastic repulsive force of the restoring elastic member 32, and the tip member 2 is shown in FIG. The posture is changed along the guide surfaces F1 and F2 to the side facing upward. At that time, the pressure of the posture operation member 31, the elastic repulsive force of the restoring elastic member 32, and the reaction force from the retaining member 21 act on the tip member connecting portion 15, and the balance of these acting forces The posture of the tip member 2 is determined. The posture of the tip member 2 is detected by the posture detection means 46 from the detection value of the movement amount detector 45. Therefore, the posture of the tip member 2 can be appropriately controlled by remote operation.

  Further, since the rotation preventing mechanism 37 for preventing the tip member 2 from rotating around the center line CL of the tip member 2 with respect to the spindle guide portion 3 is provided, the posture operation for controlling the advancement and retreat of the posture operation member 31 is provided. Even when the tip member 2 that holds the tool 1 becomes uncontrollable due to a failure of the drive mechanism 4c or its control device, the tip member 2 rotates around the center line CL and damages the periphery of the machining site, It is possible to prevent the member 2 itself from being damaged.

  Since the posture operation member 31 is inserted through the guide hole 30a of the guide pipe 30, the posture operation member 31 does not shift in the direction intersecting the longitudinal direction and can always act properly on the tip member 2. Thus, the posture changing operation of the tip member 2 is accurately performed. Further, since the posture operation member 31 is made of a wire and is flexible, the posture changing operation of the tip member 2 is reliably performed even when the spindle guide portion 3 is curved. Furthermore, since the center of the connecting portion between the spindle 13 and the rotating shaft 22 is at the same position as the center of curvature O of the guide surfaces F1 and F2, a force for pushing and pulling against the rotating shaft 22 by changing the posture of the tip member 2 is increased. Accordingly, the posture of the tip member 2 can be changed smoothly.

  This remote control type actuator is used, for example, for cutting the medullary cavity of bone in artificial joint replacement surgery. During the operation, all or part of the distal end member 2 is inserted into the patient's body. The For this reason, if the posture of the tip member 2 can be changed by remote control as described above, the bone can be processed while the tool 1 is always held in an appropriate posture, and the artificial joint insertion hole is finished with high accuracy. Can do.

  The elongated spindle guide portion 3 is provided with a rotating shaft 22 at the center of the outer pipe 25, and around the rotating shaft 22, a guide pipe 30 accommodating a posture operation member 31 and a reinforcing shaft 34 are mutually connected 180. By disposing at the circumferential position forming the phase of the degree, the rotating shaft 22, the guide pipe 30, and the reinforcing shaft 34 can be provided in a well-balanced manner.

  Since the portion of the outer pipe 25 other than the groove-like portion 24b is thick, the spindle guide portion 3 has high rigidity (secondary moment of cross section). Therefore, the positioning accuracy of the tip member 2 is improved and the machinability is improved. Further, by arranging the guide pipe 30 and the reinforcing shaft 34 in the groove-like portion 24b, the guide pipe 30 and the reinforcing shaft 34 can be easily positioned in the circumferential direction, and the assemblability is good.

  Since the outer diameter surface of the rolling bearing 26 that supports the rotating shaft 22 is supported by the guide pipe 30 and the reinforcing shaft 34, the outer diameter surface of the rolling bearing 26 can be supported without using extra members. Moreover, since the preload is applied to the rolling bearing 26 by the spring elements 27A and 27B, the rotating shaft 22 made of a wire can be rotated at a high speed. Therefore, machining can be performed by rotating the spindle 13 at a high speed, the machining finish is good, and the cutting resistance acting on the tool 1 can be reduced. Since the spring elements 27A and 27B are provided between the adjacent rolling bearings 26, the spring elements 27A and 27B can be provided without increasing the diameter of the spindle guide portion 3.

In order to further increase the rigidity of the spindle guide portion 3, the outer pipe 25 and the guide pipe 30 may be fixed by a pipe fixing portion 70 as shown in FIG. The pipe fixing portion 70 of FIG. 5 is provided with an opening 71 communicating with the inside and outside of the peripheral wall of the outer pipe 25, and the periphery of the opening 71 in the outer pipe 25 and the guide pipe 30 are fixed by brazing or welding 72. . The pipe fixing portion 70 in FIG. 6 is obtained by fixing the outer pipe 25 and the guide pipe 30 by laser welding 73 from the outer diameter surface side of the outer pipe 25. Any pipe fixing part 70 can fix the outer pipe 25 and the guide pipe 30 relatively easily and firmly. In particular, the latter does not require the opening 71 in the outer pipe 25 as compared with the former, so that the rigidity of the spindle guide 3 can be further increased and the assemblability is improved.
Although illustration is omitted, even if the outer pipe 25 and the reinforcing shaft 34 are fixed by the same method as described above, the rigidity of the spindle guide portion 3 can be increased.

  This remote control type actuator can be provided with a cooling means 50 for cooling the tool 1 or the like as shown in FIG. 4 by utilizing the fact that the spindle guide portion 3 is hollow. That is, the cooling means 50 includes a coolant supply device 51 provided outside the remote control type actuator, and a tool that passes from the coolant supply device 51 through the inside of the drive unit housing 4a, the spindle guide portion 3, and the tip member 2. 1 is a coolant supply pipe 52 that guides the coolant to 1, and a portion 52 a of the coolant supply pipe 52 that passes through the spindle guide portion 3 is the outer pipe 25 itself that is the coolant supply pipe 52, and cools the inside of the outer pipe 25. The liquid passes through. The coolant guided to the tool 1 is discharged to the outer periphery of the tool 1. If such a cooling means 50 is provided, the heat generating locations such as the tool 1, the workpiece, the spindle 13, the rotary shaft 22, and the bearings 26 and 29 can be cooled by the coolant. Since the coolant is allowed to pass through the outer pipe 25, it is not necessary to provide a separate coolant supply pipe, and the spindle guide portion 3 can be simplified and reduced in diameter. Further, the cooling liquid may be used for lubricating the rolling bearings 26 and 29. By doing so, it is not necessary to use grease or the like generally used for bearings, and it is not necessary to provide a separate lubricating device. It is also possible to adopt a circulation type configuration in which the coolant guided to the tool 1 is returned to the coolant supply device 51 without being discharged to the outer periphery of the tool 1. Further, when the flow rate of the coolant passing through the outer pipe 25 is small, the tool 1 and the workpiece may be cooled by further supplying the coolant from the outside.

  The cooling liquid is preferably water or physiological saline. This is because if the coolant is water or physiological saline, the coolant does not adversely affect the living body when the tip member 2 is inserted into the living body to perform processing. When the coolant is water or physiological saline, it is desirable that the material of the parts in contact with the coolant is stainless steel having excellent corrosion resistance. Other parts constituting this remote control type actuator may also be made of stainless steel.

  In each of the above embodiments, the posture operation member 31 pushes the housing 11 to change the posture of the tip member 2. However, as shown in FIG. 7, the tip of the posture operation member 31 made of a wire and the housing 11 are connected to the connecting member 31a. The posture operation member 31 is retracted to the proximal end side by a posture change drive source (not shown) so that the posture operation member 31 pulls the housing 11 to change the posture of the distal end member 2. Also good. In this case, the restoring elastic member 32 is a tension coil spring.

  FIG. 8 shows a different embodiment. In this remote operation type actuator, a guide pipe 30 is provided instead of the reinforcing shaft 34 in the embodiment of FIGS. 1 to 3, and the posture operation member 31 can be moved forward and backward in a guide hole 30a which is an inner diameter hole of the guide pipe 30. It is inserted. That is, the two sets of the guide pipe 30 and the posture operation member 31 are arranged at circumferential positions that are 180 degrees in phase with each other. The restoring elastic member 32 is not provided. The guide surfaces F1 and F2 are spherical surfaces whose center of curvature is the point O, or cylindrical surfaces whose axis is the X axis passing through the point O.

  The drive unit 4 (not shown) is provided with two posture change drive sources 42 (not shown) for individually moving the two posture operation members 31 forward and backward, and these two posture change drives. The posture of the tip member 2 is changed by driving the sources 42 in opposite directions. For example, when the upper posture operation member 31 in FIG. 8 is advanced to the distal end side and the lower posture operation member 31 is retracted, the housing 11 of the distal end member 2 is pushed by the upper posture operation member 31. The posture of the tip member 2 is changed along the guide surfaces F1 and F2 to the side where the tip side faces downward in FIG. Conversely, when both posture operation members 31 are moved back and forth, the housing 11 of the tip member 2 is pushed by the lower posture operation member 31, so that the tip member 2 is directed upward in FIG. 8A. The posture is changed along the guide surfaces F1 and F2 to the side. At that time, the pressure of the two upper and lower posture operating members 31 and the reaction force from the retaining member 21 are acting on the tip member connecting portion 15, and the posture of the tip member 2 is determined by the balance of these acting forces. Is done. In this configuration, the housing 11 of the tip member 2 is pressurized by the two posture operation members 31, so that the posture stability of the tip member 2 is improved as compared with the embodiment in which the pressure is applied by only one posture operation member 31. Can be increased.

  FIG. 9 shows a further different embodiment. In this remote-controlled actuator, the hollow hole 24 of the outer pipe 25 is recessed from the circumferential position that forms a phase of 120 degrees to the outer periphery of the circular hole 24a at the center and the outer periphery of the circular hole 24a. It consists of three groove-like parts 24b. A guide pipe 30 is provided in each groove-like portion 24b, and a posture operation member 31 is inserted into a guide hole 30a that is an inner diameter hole of the guide pipe 30 so as to be able to advance and retract. In this example, each posture operation member 31 includes a wire 31b and a columnar pin 31c provided on the distal end side of the wire 31b. The distal end of the columnar pin 31 c is spherical, and the spherical distal end is in contact with the bottom surface of the radial groove 11 b formed on the proximal end surface of the housing 11. The restoring elastic member 32 is not provided. The guide surfaces F1 and F2 are spherical surfaces whose center of curvature is a point O, and the tip member 2 can tilt in any direction.

The drive unit 4 is provided with three posture change drive sources 42 (42U, 42L, 42R) (FIG. 12) for individually moving the three posture operation members 31 (31U, 31L, 31R) forward and backward. The attitude of the tip member 2 is changed by driving these three attitude changing drive sources 42 in conjunction with each other.
For example, when the upper one posture operation member 31U in FIG. 9 is advanced to the distal end side and the other two posture operation members 31L and 31R are moved backward, the upper posture operation member 31U causes the housing 11 of the distal end member 2 to move. By being pushed, the tip member 2 changes its posture along the guide surfaces F1 and F2 to the side in which the tip side faces downward in FIG. At this time, each posture changing drive source 42 is controlled so that the amount of advance / retreat of each posture operation member 31 is appropriate. When each posture operation member 31 is moved back and forth, the housing 11 of the tip member 2 is pushed by the left and right posture operation members 31L and 31R, so that the tip member 2 moves to the side where the tip side is upward in FIG. 9A. The posture is changed along the guide surfaces F1 and F2.
Further, when the left posture operation member 31L is advanced to the distal end side and the right posture operation member 31R is moved backward while the upper posture operation member 31U is stationary, the distal end member 2 is moved by the left posture operation member 31L. When the housing 11 is pushed, the tip member 2 changes its posture along the guide surfaces F1 and F2 to the right, that is, the side facing the back side of the paper surface in FIG. 9A. When the left and right posture operation members 31L and 31R are moved back and forth, the housing 11 of the tip member 2 is pushed by the right posture operation member 31R, so that the tip member 2 moves along the guide surfaces F1 and F2 toward the left side. Change the posture.
Thus, by providing the posture operation member 31 at three positions in the circumferential direction, the tip member 2 can be changed in posture in the directions of the upper, lower, left and right axes (X axis, Y axis). At that time, the pressure of the three posture operating members 31 and the reaction force from the retaining member 21 are acting on the tip member connecting portion 15, and the posture of the tip member 2 is determined by the balance of these acting forces. The In this configuration, since the pressure is applied to the housing 11 of the tip member 2 by the three posture operation members 31, the posture stability of the tip member 2 can be further improved. If the number of posture operation members 31 is further increased, the posture stability of the tip member 2 can be further enhanced.

  As shown in FIGS. 10 and 11, the posture operation member 31 may be composed of a plurality of force transmission members arranged without gaps in the length direction of the guide hole 30 a. In the example of FIG. 10, a plurality of force transmission members are balls 31d, and columnar pins 31c are provided on the front end side of the balls 31d. In the example of FIG. 11, the plurality of force transmission members are columnar bodies 31e such as cylinders, and columnar pins 31c are provided on the front end side of the columnar bodies 31e. The columnar pin 31 c is the same as described above, and its spherical tip is in contact with the bottom surface of the radial groove 11 b formed on the base end surface of the housing 11.

  As described above, when the posture operation member 31 includes a plurality of force transmission members 31 d and 31 e, the posture of the tip member 2 is changed by moving the tip member 2 toward the side pressing the tip member 2 at the tip of the posture operation member 31. Let Even if the posture operation member 31 is composed of a plurality of force transmission members 31d and 31e, it is possible to reliably act on the tip member 2. Since the force transmission members 31d and 31e are arranged in the guide hole 30a, the posture operation member 31 does not shift in the direction intersecting the longitudinal direction, and can always act properly on the tip member 2. The posture changing operation of the tip member 2 is accurately performed. Even if each of the force transmission members 31d and 31e is a rigid body, the posture operation member 31 as a whole is flexible, so that the posture changing operation of the tip member 2 can be performed even when provided on the curved spindle guide portion 3. Surely done.

  10 and 11 show an example in which the posture operation member 31 is provided at three circumferential positions at a phase of 120 degrees, but the posture operation member 31 is at two positions at a phase of 180 degrees. Even when the circumferential position is provided, or when the posture operation member 31 provided at one place in the circumferential direction is combined with the restoring elastic member 32 corresponding thereto, the force transmission members 31d and 31e are configured. The posture operation member 31 can be applied.

  When the posture operation member 31 is provided at three locations in the circumferential direction as shown in FIGS. 9, 10, and 11, the posture change drive mechanism 4c can be configured as shown in FIG. 12, for example. That is, three posture change drive sources 42 (42U, 42L, 42R) for individually moving the posture operation members 31 (31U, 31L, 31R) forward and backward are arranged in parallel on the left and right sides, and each posture change drive source is provided. A lever 43b (43bU, 43bL, 43bR) corresponding to 42 is provided so as to be rotatable around a common support shaft 43a, and each lever 43b has a long distance from the support shaft 43a at an action point P1 (P1U, P1L, P1R). The force of the output rod 42a (42aU, 42aL, 42aR) of each posture changing drive source 42 is applied, and a force is applied to the posture operating member 31 at a force point P2 (P2U, P2L, P2R) having a short distance from the support shaft 43a. As a configuration. Thereby, the output of each posture change drive source 42 can be increased and transmitted to the corresponding posture operation member 31. The rotary shaft 22 passes through an opening 44 formed in the lever 43bU for the upper posture operation member 31U.

  FIG. 13 is a cutaway side view of a tool rotation drive mechanism and a posture change drive mechanism of an embodiment in which the configuration of the posture operation drive mechanism 4c is different, and FIG. 14 is an enlarged view of a connection portion between the posture operation member 31 and the drive unit housing 4a. FIG. In this embodiment, a male screw portion 36a is formed at the base end of the posture operation member 31 made of a wire, and this male screw portion 36a is screwed with a female screw portion 36b formed in the drive portion housing 4a. The male screw portion 36a and the female screw portion 36b constitute a screw mechanism 36. By rotating the base end of the posture operating member 31 by driving the posture changing drive source 42, the posture operating member 31 moves forward and backward by the action of the screw mechanism 36.

  In the posture changing drive mechanism 4 c, for example, the rotation of the output shaft 42 a of the posture changing drive source 42 formed of an electric rotary actuator is reduced and transmitted to the base end of the posture operating member 31 via the reduction rotation transmission mechanism 49. . The decelerating rotation transmission mechanism 49 is rotatably supported by a circular spur gear 49a attached to the output shaft 42a of the attitude changing drive source 42, and a support member 60 fixed to the drive unit housing 4a, and meshes with the circular spur gear 49a. The rotation is transmitted from the sector spur gear 49b to the base end side extension 63 of the posture operation member 31 by the rotation sliding portion 62 provided on the rotation center axis of the sector spur gear 49b. The sector spur gear 49 b has a larger pitch circle diameter than the circular spur gear 49 a, and the rotation of the output shaft 42 a is decelerated and transmitted to the base end of the posture operation member 31. Providing the decelerating rotation transmission mechanism 49 allows the base end of the posture operating member 31 to rotate at a low speed even with a small rotary actuator that rotates at high speed, so that a small rotary actuator can be used as the posture changing drive source 42. It becomes possible. The tool rotation drive mechanism 4b has the same configuration as described above.

In each of the above embodiments, the rotation prevention mechanism 37 of the tip member 2 is provided, but the rotation prevention mechanism 37 may not be provided.
Further, even when the guide pipe 30 and the posture operation member 31 are provided at a plurality of locations in the circumferential direction, the outer pipe 25 and each guide pipe 30 may be fixed by the pipe fixing portion 70. Thereby, the rigidity of the spindle guide part 3 can further be improved.

  In each of the above embodiments, the spindle guide portion 3 has a linear shape. However, in the remote control type actuator of the present invention, the posture operation member 31 is flexible, and the posture of the tip member 2 is maintained even when the spindle guide portion 3 is curved. Since the changing operation is performed reliably, the spindle guide portion 3 may be curved in the initial state as shown in FIG. Alternatively, only a part of the spindle guide portion 3 may be curved. If the spindle guide portion 3 is curved, it may be possible to insert the distal end member 2 to the back of the bone, which is difficult to reach in the straight shape, so that the hole for artificial joint insertion can be accurately processed in artificial joint replacement surgery. It becomes possible to finish.

  When the spindle guide portion 3 has a curved shape, the outer pipe 25, the guide pipe 30, and the reinforcing shaft 34 need to have a curved shape. The rotating shaft 22 is preferably made of a material that is easily deformed, and for example, a shape memory alloy is suitable.

  The medical remote control actuator has been described above, but the present invention can be applied to remote control actuators for other purposes. For example, in the case of machining, drilling of a curved hole or cutting of a deep part inside the groove is possible.

It is a figure which shows schematic structure of the remote control type actuator concerning embodiment of this invention. (A) is a cross-sectional view of the tip member and spindle guide portion of the remote operation type actuator, (B) is a IIB-IIB cross-sectional view thereof, (C) is a diagram showing a connection structure between the tip member and the rotating shaft, (D ) Is a view of the housing of the tip member as seen from the base end side. (A) is the figure which combined and displayed the control system in the front view of the tool rotation drive mechanism and attitude | position change drive mechanism of the remote operation type | mold actuator, (B) is the IIIB-IIIB sectional drawing. It is a figure which shows schematic structure at the time of providing a cooling means in the remote control type actuator of FIG. (A) is sectional drawing of the front-end | tip member and spindle guide part of the remote control type actuator concerning different embodiment of this invention, (B) is the top view. (A) is sectional drawing of the front-end | tip member and spindle guide part of the remote control type actuator concerning further different embodiment of this invention, (B) is the top view. (A) is a sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to a different embodiment of the present invention, (B) is a sectional view of VIIB-VIIB, and (C) is a proximal end side housing of the distal end member. It is the figure seen from. (A) is a sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to still another embodiment of the present invention, (B) is a sectional view of the VIIIB-VIIIB, and (C) is a proximal end of a housing of the distal end member. It is the figure seen from the side. (A) is a sectional view of a tip member and a spindle guide portion of a remote control type actuator according to still another embodiment of the present invention, (B) is a sectional view of IXB-IXB, and (C) is a base end of a housing of the tip member. It is the figure seen from the side. (A) is a sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to still another embodiment of the present invention, (B) is an XB-XB sectional view thereof, and (C) is a proximal end of a housing of the distal end member. It is the figure seen from the side. (A) is a sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to still another embodiment of the present invention, (B) is a sectional view of the XIB-XIB, and (C) is a proximal end of a housing of the distal end member. It is the figure seen from the side. FIG. 12 is a cutaway side view of the tool rotation drive mechanism and the attitude change drive mechanism of the remote operation type actuator shown in FIGS. 9, 10, and 11. FIG. 6 is a cutaway side view of a tool rotation drive mechanism and a posture change drive mechanism of a remote operation type actuator having different configurations of posture operation drive mechanisms. It is an enlarged view of the connection part of the attitude | position operation member and drive part housing of the remote control type actuator. It is a figure which shows schematic structure of the remote control type actuator from which the shape of a spindle guide part differs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tool 2 ... Tip member 3 ... Spindle guide part 4a ... Drive part housing 5 ... Controller 13 ... Spindle 15 ... Tip member connection part 22 ... Rotating shaft 24 ... Hollow hole 24a ... Circular hole part 24b ... Groove-like part 25 ... Outer Pipes 26, 29 ... Rolling bearings 27A, 27B ... Spring element 30 ... Guide pipe 30a ... Guide hole 31 ... Posture operating member 32 ... Restoring elastic member 34 ... Reinforcement shaft 41 ... Tool rotation drive source 42 ... Posture change drive source 70 ... Pipe fixing part 71 ... Opening 72 ... Brazing or welding 73 ... Laser welding

Claims (14)

An elongated spindle guide part, a tip member attached to the tip of the spindle guide part via a tip member connecting part so that the posture can be freely changed, and a drive part housing to which the base end of the spindle guide part is coupled. ,
The tip member rotatably supports a spindle that holds a tool, and the spindle guide portion is provided in a hollow outer pipe that is an outer shell of the spindle guide portion, and in a hollow hole that penetrates both ends of the outer pipe. A rotation shaft for transmitting the rotation of the drive source for rotating the tool in the drive unit housing to the spindle, and a hollow guide pipe provided in the hollow hole and penetrating at both ends, the tip of which is the tip member. A posture operation member for changing the posture of the tip member by contact and advance / retreat operation is inserted into the guide pipe so as to freely advance and retract, and a posture change drive source for moving the posture operation member forward and backward is provided in the drive unit housing,
The hollow hole is composed of a circular hole portion at the center and a groove-like portion recessed from the circular hole portion toward the outer diameter side, the rotating shaft is arranged in the circular hole portion, and the groove-like portion is A remote control type actuator characterized by arranging a guide pipe.   2. The remote control type actuator according to claim 1, wherein a secondary moment of section of the outer pipe is equal to or greater than ½ of a solid shaft having the same outer diameter.   3. The posture operation member according to claim 1, wherein the posture operation member includes a plurality of force transmission members arranged in a line along the length direction of the guide pipe or a wire along the length direction of the guide pipe. Remote control type actuator.   4. The restoring elasticity according to claim 1, wherein the guide pipe and the posture operation member inserted into the guide pipe are provided at only one position, and the tip member is urged toward a predetermined posture side. 5. A remote operation type actuator provided with a member, wherein the posture operation member changes the posture of the tip member against an urging force of the elastic member for restoration.   4. The guide pipe and the posture operation member inserted into the guide pipe are provided at two locations according to claim 1, and the posture change drive source is individually provided for each posture operation member. A remote-operated actuator that is provided on the front end and changes and maintains the posture of the tip member by balancing the acting forces of the two posture operation members on the tip member.   4. The posture according to claim 1, wherein the tip end connecting member supports the tip member so as to be tiltable in an arbitrary direction, and is inserted into the guide pipe and the guide pipe. 5. Operation members are provided at three or more positions around the tilt center of the tip member, and the posture changing drive source is provided individually for each posture operation member, to the tip member of the three or more posture operation members. A remote-operated actuator that changes and maintains the posture of the tip member by balancing the acting forces.   The rolling bearing according to claim 1, wherein a plurality of rolling bearings that rotatably support the rotating shaft in the spindle guide portion are provided, and a preload is applied to the rolling bearings between adjacent rolling bearings. Remote control type actuator with spring element to give.   The remote operation according to any one of claims 1 to 7, wherein a rolling bearing that rotatably supports the rotating shaft in the spindle guide portion is provided, and an outer diameter surface of the rolling bearing is supported by the guide pipe. Type actuator.   9. The remote control type actuator according to claim 7, further comprising a cooling unit that cools the bearing with a coolant that passes through the inside of the outer pipe.   10. The remote control type actuator according to claim 1, further comprising a cooling unit that cools the tool with a coolant that passes through the inside of the outer pipe or a coolant supplied from outside. 11.   11. The remote operation type actuator according to claim 1, further comprising a pipe fixing portion that fixes the outer pipe and the guide pipe.   12. The remote according to claim 11, wherein the pipe fixing portion is provided with an opening communicating with the inside and outside of the peripheral wall of the outer pipe, and the periphery of the opening in the outer pipe and the guide pipe are fixed by brazing or welding. Operation type actuator.   12. The remote control type actuator according to claim 11, wherein the pipe fixing portion fixes the outer pipe and the guide pipe by laser welding from an outer diameter surface side of the outer pipe.   14. The remote control type actuator according to claim 1, wherein the spindle guide portion has a curved portion.

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