WO2011148892A1 - Remote operation type actuator - Google Patents

Abstract

A remote operation type actuator, capable of changing by remote operation the attitude of a tool provided to the front end of the actuator body, capable of reliably supporting the actuator body, and capable of accurately changing the position and attitude of the actuator body. An actuator body (5) is provided with an elongated spindle guide section (3), a front end member (2) which is mounted to the front end of the spindle guide section (3) in such a manner that the attitude of the front end member (2) can be changed, a tool (1) which is rotatably provided to the front end member (2), and a body's base end housing (4) to which the base end of the spindle guide section (3) is joined. A link operation device (7) for supporting the actuator body (5) is configured by connecting an output member (105) on the body's base end housing (4) side to an input member (104) on the base member (6) side in such a manner that the position and attitude of the output member (105) can be changed through three or more sets of link mechanisms (101). The remote operation type actuator is also provided with flexible wires (9A, 9B) for transmitting to the actuator body (5) the rotational force of a rotational tool drive source (41) and an attitude changing drive source (42).

Description

Remote control type actuator Related applications

This application claims the priority of Japanese Patent Application No. 2010-122395 filed on May 28, 2010, which is incorporated herein by reference in its entirety.

The present invention relates to a remote operation type 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 surgery in which a joint that has been 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.

In artificial joint replacement surgery, skin incision and muscle cutting are involved. 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 US Pat. No. 5,769,092

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, the bones of patients undergoing artificial joint replacement 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 remotely change the posture of the tool provided at the tip for the purpose of relatively easily and accurately processing the hole for inserting the artificial joint. . 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. Further, it is expected that the pipe portion has a curved portion, and it is desired that the posture changing operation can be surely performed even in that case.

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.

Also, when a person directly operates a remote control type actuator, hand tremors etc. affect the positioning accuracy of the tool with respect to the workpiece. Therefore, a lot of experience is required to process with high accuracy. In particular, when the guide portion has a curved shape, it is difficult to predict the position of the tool provided at the tip of the guide portion, and the operation becomes more complicated and difficult. Along with that, the cutting time also becomes longer. When using a remote control type actuator for an artificial joint replacement operation, if the cutting time is long, the burden on the patient is large.

Therefore, the remote operation type actuator is a remote operation type actuator supported by a support device having one degree of freedom or two degrees of freedom or more. Thereby, adverse effects such as hand tremors can be eliminated. As this type of remote operation type actuator, for example, the one described in Patent Document 5 is known. However, since the remote control type actuator cannot change the posture of the tool, it cannot perform fine machining. It was.

According to the present invention, the posture of a tool provided at the tip of the actuator body can be changed by remote control, the actuator body is securely supported, the actuator body is lightweight, and its position and posture are accurately changed. An object of the present invention is to provide a remotely operated actuator capable of performing

In the remote control type actuator according to the present invention, the position and orientation of the actuator body having a tool at the tip can be changed with respect to the base member by the link actuator. The actuator main body includes 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 the tool provided rotatably on the tip member; And a main body base end housing to which the base end of the spindle guide portion is coupled. The tip member rotatably supports a spindle that holds the tool, and the spindle guide portion includes a rotation shaft that transmits the rotation of a tool rotation drive source to the spindle, and guide holes that penetrate both ends. And a posture operation member that changes the posture of the tip member when the tip is in contact with the tip member is movably inserted into the guide hole so that the rotation of the posture change drive source can be moved forward and backward. It is assumed that an operation conversion mechanism that converts and advances and retracts the posture operation member is provided in the main body base end housing.

In the link actuating device, an output member coupled directly or indirectly to the main body proximal housing is connected to three or more sets of link mechanisms with respect to an input member coupled directly or indirectly to the base member. The link mechanism is connected to the input member and the output member in such a manner that one end of the link mechanism can be rotated, and the input side and output side end link members are connected to the input member and the output member. A central link member rotatably connected to the other end of each end link member, and each link mechanism has a geometric model expressing each link member as a straight line, the central portion of the central link member The input side portion and the output side portion are symmetrical with each other, and each of the two or more sets of link mechanisms is moved to two or more sets of the link mechanisms of the three or more sets of link mechanisms. It is allowed and that provided a link mechanism drive source for controlling the attitude of the output member. Then, either or both of the tool rotation drive source and the attitude change drive source are provided on the input member or the base member of the link actuator, and the rotational force of the drive source is converted to the rotary shaft or the motion conversion. A flexible wire is provided for transmission to the mechanism.

The link actuating device can be rephrased as follows. That is, the link actuating device connects the end link members so as to be rotatable with respect to the input member and the output member provided on the input side and the output side, respectively, and centers the end link members on the input side and the output side. There are three or more sets of link mechanisms that are rotatably connected to the link members, the input side and the output side are geometrically the same with respect to the cross section at the center of each link mechanism, and each of the link mechanisms connected to the input members Among the rotation pairs of the link mechanism, a link mechanism drive source that arbitrarily controls the posture of the output member is provided for two or more sets of link mechanisms.

According to this configuration, a bone or the like is cut by the rotation of the tool provided on 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 at a position away from the tip member, and the posture change of the tip member is performed by remote control. Since the posture operation member is inserted into the guide hole, the posture operation member does not shift in the direction intersecting the longitudinal direction, and can always act properly on the tip member, and the posture change operation of the tip member Is done accurately.

The main body base end housing of the actuator body is fixed to the output member of the link actuator, and the actuator body is supported by the link actuator, so that the position and posture of the actuator body are stabilized. In the link actuating device, a two-degree-of-freedom mechanism in which an output member can be moved in two orthogonal axes is constituted by three or more sets of link mechanisms and a link mechanism drive source. This two-degree-of-freedom mechanism can widen the movable range of the output member. For example, the maximum bending angle between the central axis of the input member and the central axis of the output member is about ± 90 °, and the turning angle of the output member relative to the input member can be set in the range of 0 ° to 360 °. By providing a link mechanism drive source that arbitrarily controls the posture of the output member for two or more sets of link pairs of each link mechanism connected to the input member, the output member can be in any posture. Easy to decide. The reason why the number of rotation pairs of the link mechanism provided with the link mechanism drive source is two or more is that it is necessary to determine the posture of the output member with respect to the input member.

As described above, the actuator body can be stably supported at an arbitrary position and posture by the link actuating device, and the posture change of the tip member with respect to the spindle guide portion can be accurately performed, so that fine machining can be performed. Specifically, processing of a narrow portion and processing with high accuracy can be performed. Moreover, the processing time can be shortened. Thereby, a patient's burden can be reduced when using it for an operation.

In this invention, it is preferable that the axis of the end on the drive unit housing side of the rotating shaft is parallel to a central axis passing through the spherical center of the output member. With this configuration, the rotary shaft of the motion conversion mechanism and the rotary shaft for rotating the tool can be provided in the drive unit housing in parallel with each other, and the drive unit housing can be simplified.

The motion conversion mechanism is a screw mechanism type linear motion mechanism that converts a rotational motion of the flexible wire into a linear reciprocating motion, and the posture operation member is a final output portion of the motion conversion mechanism that is the linear motion mechanism. You may move forward and backward. When the motion conversion mechanism is a screw mechanism type linear motion mechanism, it is possible to generate a large thrust with a small and compact structure. In this case, the rotating shaft of the screw mechanism and the rotating shaft for rotating the tool are parallel to each other.

In addition, the motion conversion mechanism is configured by combining a worm that rotates by the rotation of the flexible wire and a worm wheel that meshes with the worm, and a contact portion that is a part of the worm wheel includes the posture operation member. The posture operation member may be moved back and forth by sliding contact. Even when the motion conversion mechanism is configured by combining a worm and a worm wheel, a large thrust can be generated with a small and compact structure. In this case, the worm and the rotating shaft for rotating the tool are parallel to each other.

In the present invention, it is preferable that a through hole is provided in each of the input member and the output member and the flexible wire is provided through each through hole. If the flexible wire is provided through the through holes of the input member and the output member, the flexible wire always passes through the inside of each link mechanism regardless of the posture of each link mechanism. Thereby, it can prevent that a flexible wire contacts other members.

In this invention, the flexible wire may be guided by a wire guide member fixed to the central link member and positioned inside each link mechanism. Regardless of the posture of each link mechanism, the central link member of at least two of the three or more link mechanisms passes on one orbital circle. Therefore, if a flexible wire is guided by a wire guide member fixed to the central link member and positioned inside each link mechanism, interference between the flexible wire and other members, for example, the central link member and the end link member Can be prevented.

In the present invention, the flexible wire supports a flexible inner wire whose both ends are a rotational input end and an output end, respectively, in a flexible outer tube by a plurality of rolling bearings. A structure in which a spring element for applying a preload to these rolling bearings is provided between adjacent rolling bearings is preferable. An inner wire can be protected by providing the inner wire which becomes a rotating shaft of a flexible wire inside the outer tube. The inner wire is rotatably supported by a plurality of rolling bearings, and a spring element is provided between adjacent rolling bearings, so that the natural frequency of the inner wire can be suppressed from being lowered, and the inner wire can be rotated at high speed.

In this invention, it is preferable to provide a reduction mechanism for reducing the rotation of the flexible wire on the output side of the flexible wire. The rotations of the tool rotation drive source and the attitude change drive source are decelerated by the reduction mechanism and transmitted to the rotation shaft of the motion conversion mechanism and the rotation shaft for tool rotation. Since the speed reduction mechanism is provided, even if the torque output from the tool rotation drive source or the posture change drive source is small, a large torque can be generated on the rotary shaft of the motion conversion mechanism and the rotary shaft for tool rotation. In particular, since the posture changing operation of the tip member performed by driving the posture changing drive source requires a large torque at a relatively low rotational speed, the effect of providing a speed reduction mechanism is great. If a speed reduction mechanism is provided, as described above, even if the torque acting on the flexible wire is small, a large torque can be generated, so that a thin flexible wire can be used. As a result, the minimum curvature of the flexible wire can be reduced, and it is easy to cope with changes in the posture of each link mechanism of the link actuator. Further, since the twist of the flexible wire is small, the positioning accuracy of the tool provided on the tip member is good.

It is preferable to provide a position detection means for detecting the operating position of the power transmission member in the power transmission member between the speed reduction mechanism and the posture operation member. The advance / retreat position of the posture operation member can be estimated from the operation position of the power transmission member detected by the position detection means. By using the information regarding the position of the posture operation member estimated as described above, the posture change drive source can be feedback-controlled. Therefore, even if the flexible wire is twisted, the positioning control of the tip member can be performed accurately.

In the case of having the position detection means, the input member and the output member are each provided with a through hole, and each through hole is provided with a wiring connecting the position detection means and a control unit for receiving a detection signal of the position detection means. good. If the wiring of the position detection means is provided through the through holes of the input member and the output member, the wiring always passes inside each link mechanism regardless of the posture of each link mechanism. As a result, the wiring can be prevented from contacting other members.

In this invention, the spindle guide portion may have a curved portion. If the posture operation member is made 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 operation type actuator of the present invention is suitable as an actuator for medical surgery because it has the above-described actions and effects.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the present invention.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and description, and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.
It is a side view showing a schematic structure of a remote control type actuator concerning a 1st embodiment of this invention. It is a side view which shows schematic structure of the remote control type actuator concerning 2nd Embodiment of this invention. (A) is a longitudinal sectional view of the tip member and spindle guide portion of the remote control type actuator shown in FIG. 1, (B) is a sectional view taken along the line IIIB-IIIB, and (C) is a connection structure of the tip member and the rotating shaft. FIG. (A) is a longitudinal sectional view of the main body base end housing of the remote control type actuator, and (B) is a sectional view taken along the line IVB-IVB. It is a front view of the link operating device of the remote control type actuator. It is a front view which shows the different state of the link actuating device. It is a perspective view of the link actuating device. It is the schematic diagram which expressed one of the link mechanisms of the link actuating device with a straight line. It is a longitudinal cross-sectional view of the input member of the link actuator, the input side end link member, and the central link member. (A) The longitudinal cross-sectional view of the flexible wire of the remote operation type actuator, (B) is an XB part enlarged view, (C) is an XC part enlarged view. It is a front view of a different link actuator. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 11. (A) is a longitudinal sectional view of a main body base end housing having a different internal configuration, and (B) is a sectional view taken along line XIIIB-XIIIB. (A) is a longitudinal sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to a third embodiment having a different mechanism for changing the posture of the distal end member, and (B) is a sectional view taken along the line XIVB-XIVB. (A) is a longitudinal sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to a fourth embodiment in which the mechanism for changing the posture of the distal end member is further different, and (B) is a sectional view taken along the line XVB-XVB. . (A) is a longitudinal sectional view of a distal end member and a spindle guide portion of a remote control type actuator according to a fifth embodiment in which the mechanism for changing the attitude of the distal end member is further different, and (B) is a sectional view taken along the line XVIB-XVIB. . (A) is a longitudinal sectional view of a main body base end housing of the remote control type actuator shown in FIGS. 15 and 16, and (B) is a sectional view taken along the line XVIIB-XVIIB.

1 and 2 are diagrams showing a schematic configuration of a remote control type actuator according to first and second embodiments of the present invention. In this remote operation type actuator, the position and posture of an actuator body 5 having a rotary tool 1 at its tip can be changed by a link actuator 7 with respect to a drive unit housing 6 as a base member. The actuator body 5 is attached to the output member 105 of the link actuator 7 via the attachment member 100. In the drive unit housing 6, drive sources 41, 42, and 121 for operating each operation part of the remote control type actuator are provided. The rotational forces of the tool rotation drive source 41 and the attitude change drive source 42 are transmitted to the actuator body 5 via the flexible wires 9A and 9B, respectively. Each drive source 41, 42, 121 is controlled by a controller 8 connected to the drive unit housing 6.

The actuator body 5 includes a distal end member 2 that holds the rotary tool 1, an elongated spindle guide portion 3 that is attached to the distal end of the distal end member 2 so that its posture can be freely changed, and a proximal end of the spindle guide portion 3. A main body proximal housing 4 coupled thereto. In the main body base end housing 4, a later-described operation conversion mechanism 44 is provided. FIG. 1 and FIG. 2 are different from each other in the actuator body 5. In FIG. 1, the spindle guide 3 is straight, whereas in FIG. 2, the spindle guide 3 is curved. is there.

3A to 3C, the internal structure of the tip member 2 and the spindle guide part 3 will be described. 3 (A) to 3 (C) show the remote control type actuator of FIG. 1. Even when the spindle guide portion 3 has a straight shape as shown in FIG. 1, the spindle guide portion 3 is curved as shown in FIG. Even when the shape is the same, the internal structures of the tip member 2 and the spindle guide portion 3 are basically the same.

As shown in FIG. 3 (A), 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, which is one axis that passes through the center of curvature O and is orthogonal to the center line CL, the guide surfaces F1 and F2 pass through the point O. A cylindrical surface with the axis as the center may be used.

The spindle guide portion 3 has a rotating shaft 22 that transmits the rotation of the tool rotation drive source 41 (FIG. 1) to the spindle 13. The rotation shaft 22 is provided from the spindle guide portion 3 to the main body base end housing 4 (FIG. 1), and its base end is located near the base end of the main body base end housing 4 (FIG. 1). 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. 3C, 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 O 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.

3 (A) has an outer pipe 25 that is an outer shell of the spindle guide portion 3, and the rotating shaft 22 is located at the center of the outer pipe 25. As shown in FIG. The rotating shaft 22 is rotatably supported by a plurality of rolling bearings 26 that are disposed 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.

Between the inner diameter surface of the outer pipe 25 and the rotary shaft 22, one guide pipe 30 penetrating at both ends is provided, and the posture operation member 31 advances and retreats in the guide hole 30 a which is the inner diameter hole of the guide pipe 30. It is inserted freely. In this example, the posture operation member 31 includes a wire 31a and columnar pins 31b provided at both ends thereof. The distal end of the columnar pin 31b on the distal end member 2 side is spherical and is in contact with the proximal end surface of the housing 11 of the distal end member 2. The distal end of the columnar pin 31b on the main body base housing 4 side is also spherical, and is in contact with the front surface of a linear motion member 51 (FIGS. 4A and 4B) described later.

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.

Further, between the inner diameter surface of the outer pipe 25 and the rotary shaft 22, as shown in FIG. 3B, a plurality of lines are provided on the same pitch circle C as the guide pipe 30 separately from the guide pipe 30. A reinforcing shaft 34 is arranged. These reinforcing shafts 34 are for ensuring the rigidity of the spindle guide portion 3. The intervals between the guide pipe 30 and the reinforcing shaft 34 are equal. The guide pipe 30 and the reinforcing shaft 34 are in contact with the inner diameter surface of the outer pipe 25 and the outer diameter surface of the rolling bearing 26. Thereby, the outer diameter surface of the rolling bearing 26 is supported.

4 (A) and 4 (B) show the internal structure of the main body base end housing 4. As shown in FIG. 4A, the rotation shaft 22 is provided in the left and right direction in the main body base end housing 4, and the base end is interposed via the inner wire 72 and the coupling 40 of the flexible wire 9 A. Are combined. Thereby, the rotation of the tool rotation drive source 41 (FIG. 1) is transmitted to the rotation shaft 22. The tool rotation drive source 41 is, for example, an electric motor. Further, the main body base end housing 4 rotates the output of the speed reduction mechanism 43, and the speed reduction mechanism 43 that decelerates and outputs the rotation of the posture changing drive source 42 (FIG. 1) transmitted by the flexible wire 9B. A motion converting mechanism 44 is provided as a linear motion mechanism that converts motion into linear reciprocating motion. The attitude changing drive source 42 is a rotary actuator. The rotary actuator may be an electric type or a fluid pressure type. The flexible wires 9A and 9B will be described in detail later.

The motion conversion mechanism 44 is a linear motion mechanism having a screw mechanism. Specifically, the motion converting mechanism 44 includes a ball screw 47 supported at both ends by bearings 45 and one end connected to the output shaft 43a of the speed reduction mechanism 43 via a coupling 46, and screwed into the ball screw 47. A ball screw mechanism 49 including a nut 48 is provided, and a linear motion member 51 guided to be movable in the axial direction of the ball screw 47 by a linear guide 50 (FIG. 4B) is fixed to the nut 48. Yes. The linear motion member 51 is a final output portion of the motion conversion mechanism 44, and the columnar pin 31 b at the proximal end of the posture operation member 31 is in contact with a contact portion 51 a formed of the distal end surface of the linear motion member 51.

The rotation of the output shaft 43a of the speed reduction mechanism 43 is converted into a linear motion by the ball screw mechanism 49, and the linear motion member 51 linearly moves along the linear guide 50 (FIG. 4B). When the linear motion member 51 moves to the left side of FIG. 4A, the posture operation member 31 pushed by the linear motion member 51 advances, and when the linear motion member 51 moves to the right side, the restoring elasticity The posture operation member 31 is retracted by being pushed back by the elastic repulsive force of the member 32 (FIG. 3A).

As shown in FIG. 4B, a linear scale 52 is installed on the linear motion member 51, and the scale of the linear scale 52 is read by a linear encoder 53 fixed to the main body base end housing 4. The linear scale 52 and the linear encoder 53 constitute position detecting means 54 for detecting the advancing / retreating position of the posture operation member 31. More precisely, the output of the linear encoder 53 is transmitted to the advance / retreat position estimation means 55, and the advance / retreat position estimation means 55 estimates the advance / retreat position of the posture operation member 31. That is, the position detection unit 54 detects the operating position of the linear motion member 51 that is a power transmission unit between the speed reduction mechanism 43 and the posture operation member 31, and estimates the advance / retreat position of the posture operation member 31 from the detection result.

The advance / retreat position estimation means 55 has a relationship setting means (not shown) in which the relationship between the advance / retreat position of the posture operation member 31 and the output signal of the linear encoder 53 is set by an arithmetic expression or a table, etc. The advance / retreat position of the posture operation member 31 is estimated from the signal using the relationship setting means. The advance / retreat position estimation means 55 may be provided in the controller 8 (FIG. 1) or may be provided in an external control device. The controller 8 controls the posture changing drive source 42 based on the detection value of the advance / retreat position estimating means 55.

5 and 6 are front views showing different states of the link actuator, and FIG. 7 is a perspective view of the link actuator. The link actuating device 7 includes an output member 105 coupled to the body base end housing 4 of the actuator body 5 via an attachment member 100 (FIG. 1) with respect to the input member 104 coupled to the drive unit housing 6. The position and orientation are connected to each other through a pair of link mechanisms 101, 102, and 103 (hereinafter referred to as “101 to 103”). 5 and 6, only one set of link mechanisms 101 out of the three sets of link mechanisms 101 to 103 is displayed.

Each of the link mechanisms 101 to 103 includes input side end link members 101a, 102a, and 103a (hereinafter referred to as “101a to 103a”), central link members 101b, 102b, and 103b (hereinafter referred to as “101b to 103b”). And an end link member 101c, 102c, 103c (hereinafter referred to as “101c to 103c”) on the output side, and forms a three-joint link mechanism composed of four rotating pairs. Specifically, one end of the input side end link members 101a to 103a is rotatably connected to the input member 104, and one end of the output side end link members 101c to 103c is rotatably connected to the output member 105. The other ends of the input-side end link members 101a to 103a and the output-side end link members 101c to 103c are rotatably connected to both ends of the central link members 101b to 103b, respectively.

The end link members 101a to 103a and 101c to 103c on the input side and the output side have a spherical link structure, and the spherical link centers PA and PC in the three sets of link mechanisms 101 to 103 are coincident with each other. The distance from the PC is the same. The rotational pair axis that is a connecting portion of the end link members 101a to 103a, 101c to 103c and the central link members 101b to 103b may have a certain crossing angle or may be parallel.

That is, the three sets of link mechanisms 101 to 103 have the same geometric shape. The geometrically identical shape means that a geometric model expressing each link member 101a to 103a, 101b to 103b, 101c to 103c as a straight line is an input side portion and an output side portion with respect to the central portion of the central link members 101b to 103b. Is a symmetrical shape. FIG. 8 represents one link mechanism 102 with a straight line.

The link mechanisms 101 to 103 of this embodiment are of a rotationally symmetric type, and the positional relationship between the input member 104 and the end link members 101a to 103a and the output member 105 and the end link members 101c to 103c is the center link member 101b to The position configuration is rotationally symmetric with respect to the center line A of 103b. 5 shows a state where the central axis B of the input member 104 and the central axis C of the output member 105 are collinear. FIG. 6 shows the central axis C of the output member 105 with respect to the central axis B of the input member 104. Shows a state where a predetermined operating angle is taken. Even if the postures of the link mechanisms 101 to 103 are changed, the distance L between the spherical links PA and PC on the input side and the output side does not change.

As shown in FIG. 9, the input member 104 has a through-hole 106 for insertion of a flexible wire in the center thereof along the axial direction, and a donut having a spherical outer shape so that a large angle can be taken. Further, it has a structure in which through holes 108 for inserting shaft members are formed at equal intervals in the circumferential direction in the radial direction, and the shaft members 110 are inserted into the through holes 108 via bearings 109. . The output member 105 has the same structure, and a through-hole 106 (FIG. 7) for inserting a flexible wire is formed along the axial direction at the center.

The bearing 109 includes a bearing outer ring fitted in the through hole 108 of the input member 104, a bearing inner ring fitted on the shaft member 110, and a ball or the like rotatably inserted between the bearing outer ring and the bearing inner ring. It consists of moving objects. The outer end portion of the shaft member 110 protrudes from the input member 104, and the end link members 101a, 102a, 103a and the gear member 111 are coupled to the protruding portion, and a predetermined preload amount is applied to the bearing 109 by tightening with the nut 113. Granted and fixed. The gear member 111 constitutes a part of an angle control mechanism 120 of link mechanisms 101 to 103 to be described later. A bearing 109 that rotatably supports the shaft member 110 with respect to the input member 104 is prevented from coming off from the input member 104 by a retaining ring 112.

The shaft member 110, the end link members 101a to 103a, and the gear member 111 are coupled by caulking or the like. It is possible to combine by key or serration. In that case, loosening of the coupling structure can be prevented and transmission torque can be increased.

By providing the gear member 111 at the outer end of the shaft member 110, a wide inner space S is formed inside the through hole 106 for inserting the flexible wire of the input member 104 and the link mechanisms 101 to 103. Yes. In the inner space S, flexible wires 9A and 9B are provided.

As the bearing 109, an angular ball bearing, a roller bearing, or a sliding bearing can be used in addition to the arrangement of two ball bearings as shown. The output member 105 has the same structure as the input member 104 except that the gear member 111 is not provided at the outer end portion of the shaft member 110. Although the circumferential position of the shaft member 110 may not be equal, the input member 104 and the output member 105 need to have the same circumferential positional relationship. The input member 104 and the output member 105 are shared by the three sets of link mechanisms 101 to 103, and the end link members 101a to 103a and 101c to 103c are connected to each shaft member 110.

The end link members 101a to 103a, 101c to 103c are L-shaped, one side is coupled to the shaft member 110 protruding from the input member 104 and the output member 105, and the other side is coupled to the central link members 101b to 103b. The end link members 101a to 103a and 101c to 103c have shapes in which the bent base end inside of the shaft portion 115 located on the link center side is largely cut so that a large angle can be taken.

The central link members 101b to 103b are substantially L-shaped and have through holes 114 on both sides. The central link members 101b to 103b have shapes in which the circumferential side surfaces are cut so that a large angle can be obtained. A shaft portion 115 integrally bent from the other sides of the end link members 101a to 103a and 101c to 103c is inserted through the through holes 114 on both sides of the central link members 101b to 103b via a bearing 116.

The bearing 116 includes a bearing outer ring fitted in the through hole 114 of the central link members 101b to 103b, a bearing inner ring fitted to the shaft portion 115 of the end link members 101a to 103a, 101c to 103c, and a bearing outer ring. And a rolling element such as a ball rotatably inserted between the bearing inner rings. A bearing 116 that rotatably supports the central link members 101b to 103b with respect to the end link members 101a to 103a and 101c to 103c is prevented from being detached from the central link members 101b to 103b by a retaining ring 117.

In the link mechanisms 101 to 103, the angle and length of the shaft member 110 of the input member 104 and the output member 105, and the geometric shapes of the end link members 101a to 103a and 101c to 103c are equal on the input side and the output side. When the shapes of the central link members 101b to 103b are the same on the input side and the output side, the central link members 101b to 103b and the input / output members 104 and 105 are connected to the symmetry plane of the central link members 101b to 103b. If the angular positional relationship between the end link members 101a to 103a and 101c to 103c is the same on the input side and the output side, the input member 104 and the end link members 101a to 103a are output from the geometric symmetry. The member 105 and the end link members 101c to 103c move in the same manner, and the input side and the output side rotate the same time. Will rotate at a constant speed turned the corner. The plane of symmetry of the central link members 101b to 103b when rotating at a constant speed is referred to as a uniform speed bisector.

For this reason, by arranging a plurality of link mechanisms 101 to 103 having the same geometric shape sharing the input / output members 104 and 105 on the circumference, the central link member 101b is a position where the plurality of link mechanisms 101 to 103 can move without contradiction. ˜103b is limited to the motion only on the uniform speed bisector, and the constant speed rotation can be obtained even if the input side and the output side take any operating angle.

The rotating parts of the four rotary pairs in each link mechanism 101 to 103, that is, the two link portions of the end link members 101a to 103a, 101c to 103c and the input / output members 104 and 105, and the end link members 101a to 103a, By adopting a bearing structure for the two connecting portions 101c to 103c and the central link members 101b to 103b, it is possible to reduce frictional resistance at the connecting portions and reduce rotational resistance, thereby ensuring smooth power transmission. And durability can be improved.

In this bearing structure, by applying preload, radial gaps and thrust gaps can be eliminated, rattling at the connecting part can be suppressed, the rotational phase difference between the input and output can be eliminated, and constant velocity can be maintained and vibration and vibration can be maintained. Generation of abnormal noise can be suppressed. In particular, in the bearing structure, backlash generated between input and output can be reduced by making the bearing gap a negative gap.

The link actuating device 7 controls the angle of the input side end link members 101a to 103a with respect to the input member 104 for the two or more link mechanisms 101 to 103, so that Control posture of freedom. 5 to 9, the angles of the end link members 101a to 103a of all the link mechanisms 101 to 103 are controlled. As shown in FIG. 7, the angle control mechanism 120 of the end link members 101a to 103a is provided with a link mechanism drive source 121 fixed to the drive section housing 6, and the drive section housing 6 of the link mechanism drive source 121 is provided. A bevel gear 123 is attached to an output shaft 122 projecting from the shaft, and a gear portion of the gear member 111 attached to the shaft member 110 of the input member 104 is meshed with the bevel gear 123. The link mechanism drive source 121 is, for example, an electric motor. By rotating the link mechanism drive source 121, the rotation is transmitted to the shaft member 110 via the bevel gear 123 and the gear member 111, and the end link members 101 a to 103 a change in angle with respect to the input member 104.

According to the configuration of the link operating device 7, the movable range of the output member 105 relative to the input member 104 can be widened. For example, the maximum bending angle between the central axis B of the input member 104 and the central axis C of the output member 105 can be about ± 90 °. Further, the turning angle of the output member 105 relative to the input member 104 can be set in the range of 0 ° to 360 °. By providing a link mechanism drive source 121 that arbitrarily controls the posture of the output member 105 at the rotational pair of the link mechanisms 101 to 103 connected to the input member 104, the output member 105 can be easily placed in any posture. It is decided. Since force is transmitted from the input member 104 to the output member 105 at a constant speed, the operation of the output member 105 is smooth. In this embodiment, the link mechanism drive source 121 is provided for each pair of rotation pairs of the input member 104 and the link mechanisms 101 to 103. However, if the link mechanism drive source 121 is provided for two or more pairs, the input member is provided. The posture of the output member 105 with respect to 104 can be determined.

Further, the link actuating device 7 of this configuration includes the bearing outer ring in the input / output members 104 and 105 and connects the bearing inner ring to the end link members 101a to 103a and 101c to 103c. Since the bearing structure is embedded, the outer shapes of the input / output members 104 and 105 can be enlarged without increasing the overall outer shape. Therefore, it is easy to secure a mounting space for mounting the input member 104 to the drive unit housing 6 and a mounting space for mounting the output member 105 to the main body base end housing 4.

10A to 10C show detailed structures of the flexible wires 9A and 9B. The flexible wires 9A and 9B include a flexible outer tube 71, a flexible inner wire 72 provided at a central position inside the outer tube 71, and the inner wire 72 with respect to the outer tube 71. And a plurality of rolling bearings 73 that are rotatably supported. Both ends of the inner wire 72 become a rotation input end 72a and an output end 72b, respectively. The outer tube 71 is made of resin, for example. As the inner wire 72, for example, a wire such as metal, resin, glass fiber or the like is used. The wire may be a single wire or a stranded wire.

The respective rolling bearings 73 are arranged at regular intervals along the center line of the outer tube 71, and spring elements 74 </ b> I and 74 </ b> O that apply preload to the rolling bearings 73 are provided between the adjacent rolling bearings 73. It has been. The spring elements 74I and 74O are compression coil springs, for example, and are provided so that the windings surround the outer periphery of the inner wire 72. The spring elements include an inner ring spring element 74I that generates a preload on the inner ring of the rolling bearing 73 and an outer ring spring element 74O that generates a preload on the outer ring, which are alternately arranged.

At both ends of the outer tube 71, joints 75 for connecting the outer tube 71 to other members are provided. The joint 75 includes a male screw member 76 and a female screw member 73. The male screw member 76 is a cylindrical member in which a through hole 77 is formed on the inner periphery, and a male screw portion 78 is formed on the outer periphery of the central portion in the axial direction. At one end in the axial direction of the male screw member 76, a cylindrical portion 79 having the same inner diameter and outer diameter and extending in the axial direction is provided. The cylindrical portion 79 has an outer diameter that fits into the inner diameter portion of the outer tube 71. Further, a flange portion 80 that extends to the outer diameter side is provided at the other end in the axial direction. The flange portion 80 is a coupling means for coupling to other members, and through holes 81 for inserting fasteners such as bolts are formed at a plurality of locations in the circumferential direction. The through-hole 77 has an inner diameter that gradually increases from the cylindrical portion 79 side toward the flange portion 80 side in the order of the small diameter portion 77a, the medium diameter portion 77b, and the large diameter portion 77c. A rolling bearing 82 that rotatably supports the inner wire 72 is fitted into the medium diameter portion 77b.

The female screw member 83 is a cylindrical member having a cylindrical portion 84 and a collar portion 85 extending from one end of the cylindrical portion 84 to the inner diameter side. A female screw portion 86 that is screwed into the male screw portion 78 of the male screw member 76 is formed. The inner diameter of the collar-shaped portion 85 is set to a dimension such that the outer tube 71 is fitted to the outer periphery.

When connecting the outer tube 71 to another member, first, the cylindrical portion 79 of the male screw member 76 is fitted to the inner diameter portion of the outer tube 71, and the collar portion 85 of the female screw member 83 is the same as that of the outer tube 71. In a state of being fitted to the outer diameter portion of the end, the male screw portion 78 of the male screw member 76 and the female screw portion 86 of the female screw member 83 are screwed together. As a result, the cylindrical portion 79 of the male screw member 76 and the flange-like portion 85 of the female screw member 83 sandwich and fix one end of the outer tube 71 from inside and outside. The inner wire 72 is inserted into the through hole 77 of the male screw member 76 and supported by a rolling bearing 82 fitted into the middle diameter portion 77 b of the through hole 77. Next, the flange portion 80 of the male screw member 76 is coupled to another member to be coupled. In the case of the flexible wire 9A, the other members to be coupled are the housing of the tool rotation drive source 41 and the main body base end housing 4, and in the case of the flexible wire 9B, the posture change drive source 42 and the deceleration. It is a housing of the mechanism 43. This coupling is performed by a fixing tool (not shown) such as a bolt inserted through the through hole 81. Thus, the coupling between the outer tube 71 and the other members is completed, and the states shown in FIGS. 10A to 10C are obtained.

From this state, the outer tube 71 is released from the restraint by the cylindrical portion 79 of the male screw member 76 and the flange portion 85 of the female screw member 83 by unscrewing the male screw portion 78 and the female screw portion 86. The connection with the member is released. The outer tube 71 and other members can be easily combined and released.

Further, in a state in which the outer tube 71 and the joint 75 are coupled, the coupling operation (flange portion 80) of the male screw member 76 may be used to perform coupling operation and release operation between the flexible wires 9A and 9B and other members. The joining operation and the releasing operation of these flexible wires 9A, 9B and other members are further facilitated.

A coupling 89 connected to the rotary shaft 88 is provided at the input end 72a and the output end 72b of the inner wire 72. The rotary shaft 88 connected to the input end 72a of the inner wire 72 of the flexible wire 9A is the output shaft 41a (FIG. 5) of the tool rotation drive source 41, and the rotary shaft 88 connected to the output end 72b is This is the base end of the rotating shaft 22 (FIGS. 4A and 4B). The rotary shaft 88 connected to the input end 72a of the inner wire 72 of the flexible wire 9B is the output shaft 42a (FIG. 5) of the attitude changing drive source 42, and the rotary shaft connected to the output end 72b. Reference numeral 88 denotes an input shaft 43 b (FIG. 4A) of the speed reduction mechanism 43.

The coupling 89 shown in the figure has a through hole 89a penetrating in the axial direction, and two screw holes 89b are provided in the axial direction between the through hole 89a and the outer periphery. By inserting the inner wire 72 and the rotating shaft body 88 into the through-hole 89a from both sides and pressing the tip of a screw member (not shown) such as a bolt screwed into the screw hole 89b against the inner wire 72 and the rotating shaft body 88, The inner wire 72 and the rotating shaft body 88 are fixed to the coupling 89 to connect the inner wire 72 and the rotating shaft body 88. The coupling 89 only needs to be able to connect the inner wire 72 and the rotating shaft body 88 so as to be able to transmit rotation, and may have a configuration other than the above.

The flexible wires 9A and 9B having this configuration are provided with spring elements 74I and 74O for applying a preload to the rolling bearings 73 between the adjacent rolling bearings 73, so that the natural frequency of the inner wire 72 is lowered. This can be suppressed and the inner wire 72 can be rotated at high speed. Since the inner ring spring element 74I and the outer ring spring element 74O are alternately arranged along the length of the inner wire 72, the spring elements 74I and 74O can be provided without increasing the diameter of the outer tube 71.

In the case of the flexible wire 9B, a reduction mechanism 43 that decelerates and outputs the rotation of the inner wire 72 is provided on the output side of the inner wire 72. Even if the torque transmitted by the inner wire 72 is small, a large torque can be generated. . Therefore, it is possible to realize a flexible wire 9B having a compact structure and high flexibility.

The operation of this remote control type actuator will be explained. As shown in FIG. 1, the actuator body 5 is supported by the link actuating device 7, and driven by the link mechanism drive source 121, the actuator body 5 is moved in the two orthogonal axes so as to have an appropriate position and posture. Hold. The link operating mechanism 7 has a wide movable range of the output member 105 with respect to the input member 104, and the actuator body 5 can be easily determined in an arbitrary posture. Moreover, since the actuator main body 5 is supported by the link actuator 7, the position and posture of the actuator main body 5 are stabilized.

When the tool rotation drive source 41 is driven, the rotation is transmitted to the spindle 13 (FIG. 3A) via the inner wire 72 and the rotating shaft 22 of the flexible wire 9A shown in FIG. 13 and the tool 1 rotate. A bone or the like is cut by the rotating tool 1. At that time, the posture changing drive source 42 is controlled by the controller 8 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, the housing 11 of the distal end member 2 is pushed by the posture operating member 31, and the distal end member 2 rotates around the X axis (FIG. 3B)
In FIG. 3A, the posture is changed along the guide surfaces F1 and F2 to the side where the front end side is directed downward. On the contrary, when the posture operation member 31 is retracted, 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 guided to the side in which the tip side is upward in FIG. The posture is changed along the planes F1 and F2. At this 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 are acting on the tip member connecting portion 15, and the balance of these acting forces The posture of the tip member 2 is determined.

The advance / retreat of the posture operation member 31 is performed as follows in detail. That is, the rotation of the posture changing drive source 42 is transmitted to the speed reduction mechanism 43 via the inner wire 72 of the flexible wire 9B shown in FIG. Further, the rotational motion of the output shaft 43b of the speed reduction mechanism 43 is converted into a linear reciprocating motion by the motion conversion mechanism 44 and transmitted to the linear motion member 51 which is an output member. The forward / backward movement of the linear motion member 51 is transmitted from the contact portion 51a to the proximal end of the posture operation member 31, and the posture operation member 31 moves forward / backward. Since the speed reduction mechanism 43 is provided, a large acting force can be applied to the linear motion member 51 by generating a large torque even if the torque output from the attitude changing drive source 42 is small. Therefore, the posture operation member 31 can be reliably advanced and retracted, and the tool 1 provided on the tip member 2 can be accurately positioned. Further, since the actuator main body 5 is not provided with the tool rotation drive source 41 and the posture change drive source 42, the weight of the actuator main body 5 can be reduced. As a result, the moment of inertia acting on the link mechanisms 101 to 103 shown in FIG. 7 is reduced, and the link mechanism drive source 121 can be downsized.

The posture of the tip member 2 is obtained from the forward / backward position of the posture operation member 31 detected by the position detection means 54 (FIG. 4B). Positioning accuracy of the tool 1 can be improved by performing feedback control that feeds back the detected value of the position detecting means 54, more precisely the detected value of the linear encoder 53, to the controller 8 to control the output amount of the attitude changing drive source 42. Can be made.

As shown in FIG. 3A, since the posture operation member 31 is inserted into the guide hole 30a, the posture operation member 31 is not displaced in the direction intersecting the longitudinal direction, and is always relative to the tip member 2. It can act appropriately and the posture changing operation of the tip member 2 is accurately performed. Further, since the posture operation member 31 is flexible, the posture changing operation of the tip member 2 is reliably performed even when the spindle guide portion 3 has a curved portion. 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. In addition, since the actuator body 5 is supported in a stable state, the operation is easy and the processing time can be shortened. Thereby, a patient's burden can be reduced when using it for an operation.

The elongated spindle guide portion 3 needs to be provided with the rotating shaft 22 and the posture operation member 31 in a protected state. As shown in FIG. 3B, the rotating shaft 22 is provided at the center of the outer pipe 25. By providing a configuration in which the guide pipe 30 accommodating the posture operation member 31 and the reinforcing shaft 34 are arranged side by side in the circumferential direction between the outer pipe 25 and the rotation shaft 22, the rotation shaft 22 and the posture operation member are arranged. 31 can be protected and rigidity can be ensured while reducing the weight by hollowing the inside. Also, the overall balance 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.

The example of FIG. 1 in which the spindle guide portion 3 of the actuator body 5 is linear has been described above. However, since the posture operation member 31 is flexible, the spindle guide portion 3 is curved as shown in FIG. In addition, the posture changing operation of the tip member 2 can be performed reliably. 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 be curved. The rotating shaft 22 is preferably made of a material that is easily deformed, and for example, a shape memory alloy is suitable.

11 and 12 show different configurations of the link actuator. In this link actuating device 7, a wire guide member 141 is fixedly provided on a central link member 101b of one link mechanism 101, and the flexible wire 9A, 9B is guided by this wire guide member 141. . The wire guide member 141 includes a support portion 141a whose base end is fixed to the central link member 101b, and a C-shaped guide portion 141b provided integrally at the distal end of the support portion 141a. The cut 141ba of the guide portion 141b has a size smaller than the diameter of the flexible wires 9A and 9B, and a circular opening 141c through which the flexible wires 9A and 9B pass is formed in the center. The center of the opening 141c is a position that coincides with the center 144 of the orbital circle 143 of the central link member 101b.

The central link member of at least two of the three or more link mechanisms passes on one orbital circle 143 regardless of the posture of each of the link mechanisms 101 to 103. Therefore, if the flexible wires 9A and 9B are guided by the wire guide member 141 fixed to the central link member 101b, the flexible wires 9A and 9B and other members, for example, other central link members 102b and 103b and end portions Interference with the link members 102a, 102c, 103a, 103c can be prevented. Further, the center 144 of the orbital circle 143 of the central link member 101b is always located on a straight line connecting the spherical link centers on the input side and the output side, and the distance L between the spherical link centers is the posture of each link mechanism 101-103. Since the center of the guide portion 141b of the wire guide member 141 matches the center 144 of the orbital circle 143 of the central link member 101b as described above, the flexible wire 9A , 9B can be arranged at the shortest distance at a position where there is no distance fluctuation.

FIGS. 13A and 13B show different examples of the motion conversion mechanism. The motion conversion mechanism 44 is configured by combining a worm 57 and a worm wheel 58. Specifically, the motion conversion mechanism 44 includes a worm 57 supported at both ends by bearings 45 and one end connected to the output shaft 43a of the speed reduction mechanism 43 via a coupling 46, and the worm 57 supported by the support shaft 59. And a worm wheel 58 that meshes with 57. The worm wheel 58 is a final output portion of the motion conversion mechanism 44, and the base end of the posture operation member 31 is in contact with a contact portion 58 a formed of the distal end surface of the worm wheel 58. The worm wheel 58 has a shape in which teeth are provided only at a part of the circumference, and has an opening 58b through which the rotary shaft 22 is inserted.

The rotation of the output shaft 42 a of the attitude changing drive source 42 is decelerated by the decelerating mechanism 43, further decelerated by the decelerating mechanism including the worm 57 and the worm wheel 58, and transmitted to the worm wheel 58. While the contact portion 58a of the worm wheel 58 is in sliding contact with the posture operation member 31, the worm wheel 58 swings, thereby causing the posture operation member 31 to move forward and backward. That is, when the contact portion 58a rotates to the left in FIG. 13A, the posture operation member 31 pushed by the contact portion 58a moves forward, and when the contact portion 58a rotates to the right side, The posture operation member 31 is retracted by being pushed back by the elastic repulsive force of the elastic member 32.

The advance / retreat position of the posture operation member 31 is detected by the position detection means 54. In the case of this example, the position detecting means 54 includes a detected portion 60 provided on the back surface of the worm wheel 58 and a detecting portion 61 that is fixed to the main body base end housing 4 and detects the displacement of the detected portion 60. And become. The position detection means 54 may be optical or magnetic. Precisely, the output of the detection unit 61 is transmitted to the advance / retreat position estimation means 55, and the advance / retreat position estimation means 55 estimates the advance / retreat position of the posture operation member 31. That is, the position detection means 54 detects the operating position of the worm wheel 58 that is a power transmission means between the speed reduction mechanism 43 and the posture operation member 31, and estimates the advance / retreat position of the posture operation member 31 from this detection result.

14 (A) and 14 (B) show a third embodiment in which the configuration for changing the posture of the tip member 2 is different. This remote operation type actuator is provided with two guide pipes 30 at circumferential positions that are 180 degrees in phase with each other in the outer pipe 25, and in the guide hole 30 a that is the inner diameter hole of the guide pipe 30, the same as described above. A posture operation member 31 including a posture operation wire 31a and a columnar pin 31b is inserted so as to freely advance and retract. Between the two guide pipes 30, a plurality of reinforcing shafts 34 are arranged on the same pitch circle C as the guide pipe 30. 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. 14A is advanced to the distal end side and the lower posture operation member 31 is moved backward, the housing 11 of the distal end member 2 is pushed by the upper posture operation member 31. Thus, the posture of the tip member 2 is changed along the guide surfaces F1 and F2 to the side with the tip side facing downward in FIG. On the other hand, 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. 14A. 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.

15 (A) and 15 (B) show a fourth embodiment in which the configuration for changing the posture of the tip member 2 is further different. This remote control type actuator is provided with three guide pipes 30 at circumferential positions at a phase of 120 degrees in the outer pipe 25, and the same posture as described above in a guide hole 30 a which is an inner diameter hole of the guide pipe 30. The operating member 31 is inserted so as to freely advance and retract. Between the three guide pipes 30, a plurality of reinforcing shafts 34 are arranged on the same pitch circle C as the guide pipes 30. 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 (not shown) for individually moving the three posture operation members 31 (31U, 31L, 31R) forward and backward. The posture of the tip member 2 is changed by driving the drive sources in association with each other.

For example, when one upper posture operation member 31U in FIG. 15B 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 moves the tip member 2 When the housing 11 is pressed, the distal end member 2 changes its posture along the guide surfaces F1 and F2 to the side in which the distal end side faces downward in FIG. At this time, each posture change drive source 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 in which the tip side is upward in FIG. The posture is changed along the guide surfaces F1 and F2.

Further, when the left posture operation member 31L is advanced and the right posture operation member 31R is retracted while the upper posture operation member 31U is stationary, the left posture operation member 31L is moved backward. When the housing 11 is pressed, 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. 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 to the left side along the guide surfaces F1 and F2. Change the posture.

Thus, by providing the posture operation member 31 at three positions in the circumferential direction, the posture of the tip member 2 can be changed 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.

16 (A) and 16 (B) show a fifth embodiment in which the internal structure of the spindle guide portion 3 is different from that shown in FIGS. 15 (A) and 15 (B). The spindle guide portion 3 of the remote control type actuator is configured so that the hollow hole 24 of the outer pipe 25 is out of the circumferential position where the central circular hole portion 24a and the outer periphery of the circular hole portion 24a form a phase of 120 degrees with each other. It consists of three groove-like parts 24b recessed to the radial side. The peripheral wall at the tip of the groove-like portion 24b has a semicircular cross section. And the rotating shaft 22 and the rolling bearing 26 are accommodated in the circular hole 24a, and the attitude | position operation member 31 (31U, 31L, 31R) is accommodated in each groove-shaped part 24b.

Since the outer pipe 25 has the above-described cross-sectional shape, the thickness t of the outer pipe 25 other than the groove-like portion 24b is increased, and the secondary moment of the outer pipe 25 is increased. That is, the rigidity of the spindle guide portion 3 is increased. Thereby, the positioning accuracy of the tip member 2 can be improved and the machinability can be improved. Further, since the guide pipe 30 is disposed in the groove-like portion 24b, the guide pipe 30 can be easily positioned in the circumferential direction, and the assemblability is good.

When the posture operation member 31 is provided at three places in the circumferential direction as shown in FIGS. 15A and 15B and FIGS. 16A and 16B, the motion conversion mechanism 44 is, for example, shown in FIG. , (B). FIGS. 17A and 17B show an example in which the motion conversion mechanism is a linear motion mechanism type. Each motion conversion mechanism 44 is arranged radially about the rotation shaft 22. That is, three motion conversion mechanisms 44 (44U, 44L, 44, 44L, 44L, 44L, 44L, 44L, 44L, 44L, 44L, 44L, 44L) 44R). Each posture-changing drive source is provided in a drive unit housing (not shown), and its rotation is transmitted to the speed reduction mechanism 43 via the flexible wire 9B and decelerated by the speed reduction mechanism 43 before the motion conversion mechanism. 44.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily assume various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Tool 2 ... Tip member 3 ... Spindle guide part 4 ... Main body base end housing 5 ... Actuator main body 6 ... Drive part housing (base member)
DESCRIPTION OF SYMBOLS 7 ... Link actuator 8 ... Controller 9A, 9B ... Flexible wire 13 ... Spindle 15 ... Tip member connection part 22 ... Rotating shaft 30 ... Guide pipe 30a ... Guide hole 31 ... Posture operation member 41 ... Tool rotation drive source 42 ... attitude change drive source 43 ... deceleration mechanism 44 ... motion conversion mechanism 49 ... ball screw mechanism 54 ... position detection hand 57 ... worm 58 ... worm wheel 71 ... outer tube 72 ... inner wire 73 ... rolling bearing 74I ... spring element 74O for inner ring ... outer ring spring elements 101, 102, 103 ... link mechanisms 101a, 102a, 103a ... input side end link members 101b, 102b, 103b ... center link members 101c, 102c, 103c ... output side end link members 104 ... Input member 105 ... output member 106 ... through hole 121 for insertion of flexible wire ... link構用 drive source 141 ... wire guide members 143 ... orbital circle of the intermediate link member

Claims (12)

1. A remote control type actuator body having a tool at the tip, the position and posture of the base member being changeable by a link actuator,
   The actuator body includes an elongated spindle guide part, a tip member attached to the tip of the spindle guide part via a tip member coupling part so that the posture can be freely changed, and the tool provided rotatably on the tip member; A main body base end housing to which a base end of the spindle guide portion is coupled,
   The tip member rotatably supports a spindle that holds the tool, and the spindle guide portion includes a rotation shaft that transmits the rotation of a tool rotation drive source to the spindle, and guide holes that penetrate both ends. And a posture operation member for changing the posture of the tip member when the tip is in contact with the tip member is inserted into the guide hole so as to be able to move forward and backward. An operation conversion mechanism that converts and moves the posture operation member forward and backward is provided in the main body proximal housing,
   In the link actuating device, an output member coupled directly or indirectly to the main body proximal housing is connected to the input member coupled directly or indirectly to the base member via three or more sets of link mechanisms. The link mechanism is connected to the input member and the output member in such a manner that one end of the link mechanism is rotatably connected to the input and output end link members, and the input side and the output side. A central link member rotatably connected to the other end of each end link member,
   Each of the link mechanisms has a shape in which a geometric model expressing each link member as a straight line has a shape in which an input side portion and an output side portion are symmetrical with respect to a central portion of the central link member, and the three or more sets of links It is assumed that a link mechanism drive source that controls the posture of the output member by operating each of the two or more sets of link mechanisms is provided in two or more sets of link mechanisms in the mechanism.
   Either or both of the tool rotation drive source and the attitude change drive source are provided on the input member or the base member of the link actuator, and the rotational force of the drive source is applied to the rotary shaft or the motion conversion mechanism. A remotely operated actuator provided with a flexible wire for transmission.
2. 2. The remote control type actuator according to claim 1, wherein an axis of an end of the rotating shaft on the drive unit housing side is parallel to a central axis passing through a spherical center of the output member.
3. 3. The motion converting mechanism according to claim 2, wherein the motion converting mechanism is a screw mechanism type linear motion mechanism that converts the rotational motion of the flexible wire into a linear reciprocating motion, and the final output portion of the motion converting mechanism that is the linear motion mechanism. A remote operation type actuator that causes the posture operation member to advance and retract.
4. 3. The motion conversion mechanism according to claim 2, wherein the motion conversion mechanism is configured by combining a worm that rotates by rotation of the flexible wire and a worm wheel that meshes with the worm, and a contact portion that is a part of the worm wheel has the posture. A remote operation type actuator that slides and contacts the operation member to move the posture operation member back and forth.
5. 2. The remote control type actuator according to claim 1, wherein the input member and the output member are each provided with a through hole, and the through hole is provided with the flexible wire.
6. 2. The remote control type actuator according to claim 1, wherein the flexible wire is fixed to the central link member and is guided by a wire guide member positioned inside each link mechanism.
7. 2. The flexible wire according to claim 1, wherein the flexible wire is rotatably supported by a plurality of rolling bearings in a flexible outer tube, the flexible inner wires having both ends serving as a rotation input end and a rotation end, respectively. A remote control type actuator having a structure in which a spring element is provided between adjacent rolling bearings to apply a preload to the rolling bearings.
8. 2. The remote control type actuator according to claim 1, wherein a reduction mechanism for reducing the rotation of the flexible wire is provided on the output side of the flexible wire.
9. 9. The remote operation type actuator according to claim 8, wherein the power transmission member between the speed reduction mechanism and the posture operation member is provided with a position detection means for detecting an operating position of the power transmission member.
10. 10. The remote control type according to claim 9, wherein the input member and the output member are each provided with a through-hole, and each through-hole is provided through a wiring connecting the position detection means and a control unit for receiving a detection signal of the position detection means. Actuator.
11. 2. The remote control type actuator according to claim 1, wherein the spindle guide portion has a curved portion.
12. The remote control type actuator according to claim 1, which is for medical surgery.

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