JP7217825B2 - Flexible member - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flexible member provided for a joint function part of a robot or the like.

2. Description of the Related Art Robots, manipulators, actuators, and the like in various fields have a joint function part that enables a bending motion by using a flexible member. A coil spring is disclosed in Patent Document 1 as a flexible member used in such a joint function portion.

Although the coil spring can ensure a high degree of freedom for the bending motion of the joint function part, there is a limit to miniaturization due to the need to ensure load resistance and flexibility.

JP 2014-38075 A

The problem to be solved is that there is a limit to ensuring load resistance and flexibility while achieving miniaturization.

The present invention comprises a body portion in which a plurality of closed annular wave washers are laminated in the axial direction and adjacent portions are joined by a plurality of joint portions, and which is bendable in the axial direction by elastic deformation of the wave washers, Each of the plurality of joints has a pair of linear welds, and one of the pair of welds is oriented in a direction that intersects a first line radially extending from the center of the wave washer. The most principal feature is the flexible member formed on a second line extending in the direction of the second line, and the other welded portion is formed on a third line extending in a direction crossing the second line.

Since the present invention enables bending by deformation of a plurality of wave washers, it is possible to obtain a flexible member that is compact and has excellent load resistance and flexibility.

Moreover, according to the present invention, it is possible to reliably suppress unevenness in the stress acting around the joint.

FIG. 11 is a perspective view showing a manipulator using a flexible member (Example 1); It is a front view which shows the manipulator of FIG. 1 (Example 1). FIG. 2 is a cross-sectional view of the manipulator of FIG. 1 (Example 1); 1. It is a perspective view which abbreviate|omits a part of manipulator of FIG. 1 and mainly shows a joint function part (Example 1). FIG. 5 is a side view mainly showing the joint function part of FIG. 4 (Example 1). FIG. 6 is an enlarged view of a VI portion of FIG. 5 (Example 1); FIG. 5 is a cross-sectional view showing the flexible member of the joint function part taken along the line VII-VII in FIG. 4, where (A) shows normal state and (B) shows flexed state (Example 1). FIG. 3 is a perspective view showing a wave washer having a joint (Example 1). FIG. 9 is a plan view showing an enlarged joint portion of FIG. 8 (Example 1). FIG. 4 is a plan view conceptually showing a welding spot of a welded portion of a joint (Example 1). FIG. 10 is a perspective view showing a wave washer having a joint portion according to a comparative example (Example 1). The stress distribution of the wave washer according to the comparative example of FIG. 11 is shown, FIG. 12(A) is a perspective view of the entire wave washer, and FIG. 12(B) is an enlarged view of the XII section of FIG. 1). The stress distribution of the wave washer of FIG. 8 is shown, FIG. 13(A) is a perspective view of the entire wave washer, and FIG. 13(B) is an enlarged view of section XIII of FIG. 13(A) (Example 1). It is a top view which shows the joint part which concerns on a modification (Example 1). FIG. 11 is a plan view showing a joint portion according to another modified example (Example 1); FIG. 11 is a plan view showing a joint portion according to another modified example (Example 1);

The purpose of making it possible to obtain a flexible member having excellent load resistance and flexibility while achieving miniaturization has been achieved while improving durability.

That is, the flexible member has a main body portion in which a plurality of closed annular wave washers are laminated in the axial direction and adjacent portions thereof are joined by a plurality of joint portions, and which is bendable in the axial direction due to elastic deformation of the wave washers. wherein each of the plurality of joints comprises a pair of linear welds, one of the welds extending in a direction intersecting a first line extending radially from the center of the wave washer. It is formed on a second line and the other welded portion is formed on a third line extending in a direction crossing the second line.

The pair of welded portions may be formed in a continuous linear shape.

The pair of welded portions may be V-shaped so as to overlap each other on the inner peripheral side of the wave washer.

Each of the plurality of wave washers has a plurality of peaks and valleys between the peaks in the circumferential direction, and the peaks and valleys of adjacent wave washers are in contact with each other. may be joined by a joining portion.

[Manipulator structure]
1 is a perspective view showing a manipulator using a flexible member according to Embodiment 1 of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a cross-sectional view of the same.

In this embodiment, a medical manipulator 5 will be described as an example of a robot, manipulator, or actuator having a joint function part 3 using a flexible member 1 .

The manipulator 5 constitutes the tip of a robot arm of a surgical robot and is operated by a doctor or the like. Note that the manipulator 5 may be a manual manipulator directly operated by a doctor or the like without being attached to a surgical robot. Robots, manipulators, or actuators to which the flexible member 1 can be applied are not limited to the manipulator 5, and may be those in other fields such as industrial robots.

The manipulator 5 has a shaft portion 7 , a joint function portion 3 and an end effector 9 .

The shaft portion 7 is formed in a hollow tubular shape, for example, a cylindrical shape. A drive wire 11 for driving the joint function portion 3 and a push-pull cable 13 for driving the end effector 9 pass through the shaft portion 7 . An end effector 9 is provided at the distal end of the shaft portion 7 via the joint function portion 3 .

The joint function part 3 performs a bending motion in the axial direction according to the operation of the drive wire 11 . The axial direction means a direction along the axis of the flexible member 1, which will be described later, and does not have to be a direction strictly parallel to the axis, but also includes a direction slightly inclined with respect to the axis. Details of the joint function part 3 will be described later.

The end effector 9 is a device that is attached to the movable portion 17 of the joint function portion 3 and performs a desired operation. The end effector 9 of this embodiment is a forceps and has a pair of grasping portions 9a and 9b. The end effector 9 can be oriented in a desired direction according to the bending motion of the joint function part 3, and the pair of grip parts 9a and 9b can be opened and closed according to the operation of the push-pull cable 13. As shown in FIG.

The end effector 9 is not limited to forceps, and may be scissors, a grasping retractor, a needle driver, a camera, or the like.

[Structure of Joint Function]
4 is a perspective view mainly showing the joint function part 3 with a part of the manipulator 5 of FIG. 1 omitted, FIG. 5 is a side view of the same, FIG. 6 is an enlarged view of the VI part of FIG. 7A and 7B are cross-sectional views showing the flexible member 1 of the joint function portion 3 taken along the line VII-VII in FIG. 4, FIG. 7A showing normal state, and FIG.

As shown in FIGS. 1 to 7, the joint function portion 3 includes a base portion 15, a movable portion 17, and a flexible member 1. FIG.

The base portion 15 is formed of metal or the like in a cylindrical shape and attached to the tip of the shaft portion 7 . The push-pull cable 13 is axially inserted through the axial center of the base 15, and the drive wire 11 is axially inserted around it.

The movable portion 17 is formed of metal or the like in a cylindrical shape and attached to the end effector 9 . A push-pull cable 13 is inserted through the axial center portion of the movable portion 17 , and the tip of the push-pull cable 13 is coupled to the end effector 9 .

The movable portion 17 is supported by the base portion 15 via the flexible member 1, and the distal end portion of the drive wire 11 is fixed. Therefore, the movable portion 17 can be displaced with respect to the base portion 15 by operating the drive wire 11 to orient the end effector 9 in a desired direction.

The flexible member 1 enables bending motion of the joint function portion 3 and is interposed between the base portion 15 and the movable portion 17 . The flexible member 1 bends according to displacement of the movable portion 17 with respect to the base portion 15 . A drive wire 11 and a push-pull cable 13 are axially passed through the flexible member 1 .

Both ends of the body portion 19 of the flexible member 1 are fixed to the base portion 15 and the movable portion 17, respectively. It should be noted that this fixation can be performed by a joint portion 21 or other fixation means, which will be described later.

The body portion 19 is formed by laminating a plurality of wave washers 23 in the axial direction and joining the wave washers 23 adjacent to each other in the axial direction. The body portion 19 can be bent by elastic deformation of the wave washer 23 .

Each wave washer 23 is a plate material formed of metal or the like in a closed ring shape. The wave washer 23 of this embodiment is an annular plate member made of stainless steel, and has a constant radial width and plate thickness between the inner and outer peripheries 23e and 23f.

Each wave washer 23 has a plurality of peaks 23a in the circumferential direction and valleys 23b between adjacent peaks 23a. The wave washer 23 of this embodiment has two ridges 23a that face each other in the radial direction, and two troughs 23b that face each other in the diametrical direction between the ridges 23a. Therefore, in this embodiment, the peak portions 23a and the valley portions 23b are alternately provided at intervals of 90 degrees in the circumferential direction.

The ridges 23a and the troughs 23b are formed by arcuately curved regions extending from the inner circumference 23e to the outer circumference 23f of the wave washer 23 in the axial direction. Between the wave washers 23 adjacent in the axial direction, the crests 23a of one wave washer 23 are in contact with the troughs 23b of the other wave washer. Due to the expansion and contraction of these peaks 23a and valleys 23b, each wave washer 23 can be deformed by elastic expansion and contraction in the axial direction.

The peak portions 23a and the valley portions 23b that contact each other are joined by the joining portions 21 at their contact portions. As a result, the body portion 19 of the flexible member 1 is maintained in a layered state. Details of the joint portion 21 will be described later.

In each wave washer 23, the peak portion 23a and the valley portion 23b are continuous with an inclined portion 23c. The inclined portion 23c is inclined in the circumferential direction and has a slightly twisted shape between the inner periphery 23e and the outer periphery 23f.

The inclined portion 23c is provided with an insertion hole 23d as a portion through which the drive wire 11 is passed. A plurality of insertion holes 23 d are provided in the circumferential direction of the body portion 19 . In this embodiment, since four drive wires 11 are provided at every 90 degrees in the circumferential direction, four insertion holes 23d are also provided at every 90 degrees in the circumferential direction accordingly.

Between the inclined portions 23c of the wave washers 23 adjacent in the axial direction, the insertion holes 23d communicate in the axial direction, and the drive wire 11 is inserted through the communicating insertion holes 23d. By this insertion, the flexible member 1 functions as a guide for axially passing the drive wire 11 as a through portion and for holding it in a predetermined position.

The shape of the insertion hole 23 d is substantially circular and larger than the diameter of the drive wire 11 . This difference in diameter allows inclination and displacement of the inclined portion 23c. In addition, the shape of the insertion hole 23d is not limited to a circular shape, and may be another shape such as a rectangular shape.

The shape, material, etc. of the wave washer 23 can be appropriately changed according to the characteristics required for the flexible member 1, and the like. The number of peaks 23a and valleys 23b, the radius of curvature, the angle of inclination of the inclined portion 23c, and the like can also be changed as appropriate according to the characteristics required of the flexible member 1 and the like.

[Joint]
8 is a perspective view showing a wave washer having a joint 21, FIG. 9 is an enlarged plan view showing the joint 21 of FIG. 8, and FIG. 27 is a plan view conceptually showing 27. FIG.

The joint portions 21 are arranged at regular intervals in the circumferential direction of the wave washer 23 . In this embodiment, the joints 21 are arranged every 90 degrees.

Each joint 21 consists of a pair of linear welds 25a and 25b. The pair of welded portions 25a and 25b are gradually spaced apart in the circumferential direction from the inner circumference 23e side of the wave washer 23 toward the outer circumference 23f side. Thereby, the joint portion 21 suppresses a difference in the amount of deformation between the inner periphery 23e and the outer periphery 23f of the wave washer 23 when the body portion 19 of the flexible member 1 is bent.

In this embodiment, the pair of welded portions 25a and 25b are each formed in a continuous linear shape and form a V-shape that overlaps with each other on the inner circumference 23e side of the wave washer 23. As shown in FIG.

Specifically, the welded portions 25a and 25b are formed by spot welding, and the adjacent welded spots 27 overlap or contact each other in plan view to form a continuous line. In this example, adjacent weld spots 27 overlap.

One of the welded portions 25a and 25b of the pair of welded portions 25a and 25b is formed on a second line L2 extending in a direction intersecting a first line L1 extending radially from the center of the wave washer 23. , the other welded portion 25b is formed on a third line L3 extending in a direction crossing the second line L2.

In this embodiment, the second line L2 and the third line L3 are symmetrical about the first line L1, and the angle θ between the second line L2 and the third line L3 is approximately 35 degrees. The welded portions 25a and 25b are formed linearly so that the center of the welded spot 27 is positioned on the second line L2 and the third line L3, respectively, and the opening angle is formed by the second line L2 and the third line L3. It is approximately 35 degrees which coincides with the angle θ.

The shapes of the welded portions 25a and 25b can be appropriately set according to the difference in the amount of deformation between the inner and outer peripheries 23e and 23f of the wave washer 23, as in the modifications described later.

[Bending motion of joint functional part]
In the joint function part 3 , when the doctor operates the manipulator 5 , the flexible member 1 is bent by pulling any one of the drive wires 11 . This joint function part 3 can be bent in all directions by 360 degrees by pulling several drive wires 11 in combination.

When at least one of the drive wires 11 is pulled and bent, the flexible member 1 is bent while the peaks 23a and troughs 23b are compressed in the bending inner portion with respect to the neutral axis, as shown in FIG. 7(B). The peaks 23a and valleys 23b are stretched in the outer portion.

By such deformation, the inclined portions 23c through which the operated drive wire 11 is inserted become closer to each other, and the flexible member 1 bends as a whole. This realizes a bending motion with high linearity in the load characteristics between the bending angle and the load.

At the time of such bending, the joining portion 21 suppresses the difference in the amount of deformation between the inner and outer circumferences 23e and 23f of the wave washers 23 of the flexible member 1 .

Specifically, the pair of welded portions 25a and 25b of the joint portion 21 are gradually separated in the circumferential direction from the inner circumference 23e side toward the outer circumference 23f side, so that the outer circumference 23f of the wave washer 23 is separated from the welded portion 25a. , 25b, the deformation is suppressed.

On the other hand, in the inner circumference 23e of the wave washer 23, the welded portions 25a and 25b are close to each other, and in the present embodiment, they overlap, so deformation is not suppressed unlike the outer circumference 23f.

Therefore, in each wave washer 23, the deformation amounts of the inner and outer peripheries 23e and 23f are adjusted, and occurrence of a difference in the deformation amounts of the inner and outer peripheries 23e and 23f of the wave washer 23 is suppressed.

As a result, the unevenness of the stress acting around the joint 21 is suppressed, the maximum stress is reduced, and the durability of the flexible member 1 is improved.

[Stress distribution]
FIG. 11 is a perspective view showing a wave washer 23A having a joint portion 21A according to a comparative example. FIG. 12 shows the stress distribution of the wave washer 23A according to the comparative example, FIG. 12(A) is a perspective view of the entire wave washer 23A, and FIG. 12(B) is an enlarged view of the XII portion of FIG. 12(A). . 13 shows the stress distribution of the wave washer 23 according to Example 1, FIG. 13(A) is a perspective view of the entire wave washer 23, and FIG. 13(B) is an enlarged view of section XIII of FIG. 13(A). be.

The wave washer 23A used in the flexible member (not shown) of Comparative Example and the wave washer 23 used in the flexible member 1 of Example 1 were compared in stress distribution during bending.

The flexible member of the comparative example is obtained by laminating wave washers 23A in the same manner as in the first embodiment and joining adjacent portions thereof, and has the same configuration as in the first example except for the shape of the joining portion 21A. The joints 21A each consist of a single welded portion 25A formed along the radial direction of the wave washer 23A.

In the wave washer 23A of this comparative example, there is a difference in the amount of deformation between the inner and outer circumferences 23Ae and 23Af during bending, and as a result, there is a portion with locally high stress on the inner circumference 23Ae side in the region along the joint portion 21A. I know it exists. The maximum stress at this time was 1186 MPa. In addition, in FIG. 12, the darker the color, the higher the stress (the same applies to FIG. 13).

On the other hand, in the wave washer 23 of Example 1, the difference in the amount of deformation between the inner and outer circumferences 23e and 23f during bending is suppressed, so that the area along the joint 21 extends from the inner circumference 23e side to the outer circumference 23f side. It can be seen that the stress is made uniform. The maximum stress at this time was 997 MPa, and a decrease of about 16% was observed.

In Example 1, when the opening angles between the welded portions 25a and 25b were changed to 30 degrees, 35 degrees and 40 degrees, the maximum stress was 1061 MPa, 997 MPa and 1184 MPa, respectively.

Therefore, in this embodiment, it is preferable to set the opening angle of the welded portions 25a and 25b to 30 to 40 degrees, particularly 35 degrees.

A preferred opening angle of the welded portions 25a and 25b varies depending on the width and shape of the wave washer 23 and the like.

[Effect of Example 1]
As described above, in the flexible member 1 of the present embodiment, a plurality of closed annular wave washers 23 are laminated in the axial direction and adjacent portions are joined by a plurality of joint portions 21, so that the wave washers 23 are elastically deformed. A plurality of joints 21 are formed by a pair of linear welds 25a gradually spaced apart in the circumferential direction from the inner periphery 23e of the wave washer 23 toward the outer periphery 23f. , 25b.

Therefore, in this embodiment, the linearity of the load characteristic between the bending angle and the load can be enhanced, and it is possible to obtain a flexible member that is compact and has excellent load resistance and flexibility.

Moreover, in this embodiment, the pair of welded portions 25a and 25b suppresses the difference in the amount of deformation between the inner and outer circumferences 23e and 23f when the wave washer 23 is deformed. is suppressed, the maximum stress is reduced, and the durability of the flexible member 1 can be improved.

One of the welded portions 25a and 25b is formed on a second line L2 extending in a direction intersecting a first line L1 extending radially from the center of the wave washer 23, and the other welded portion 25b is formed on a third line L3 extending in a direction crossing the second line L2.

Therefore, in the present embodiment, it is possible to reliably suppress uneven stress acting around the joint 21 .

In addition, since the pair of welded portions 25a and 25b are formed in continuous lines, the stress can be made uniform along the welded portions 25a and 25b.

In addition, since the pair of welded portions 25a and 25b are V-shaped and overlap each other on the inner circumference 23e side of the wave washer 23, the amount of deformation is not inadvertently suppressed at the inner circumference 23e of the wave washer 23. . Therefore, the pair of welded portions 25a and 25b can reduce the amount of deformation of the outer circumference 23f of the wave washer 23 to be adjusted.

Further, in the present embodiment, the expansion and contraction of the peak portions 23a and the valley portions 23b of the main body portion 19 can reliably perform the bending motion.

Furthermore, in this embodiment, the contacting peak portions 23a and valley portions 23b are joined together, so that the flexible member 1 having excellent torsional rigidity can be obtained.

In addition, in this embodiment, since the plurality of wave washers 23 have insertion holes 23d through which the drive wires 11 are inserted, the body portion 19 can be used as a guide for the drive wires 11, and the drive wires 11 can be positioned appropriately. It is possible to hold and perform a more stable and accurate bending motion.

[Modification]
Modified examples of the shape of the joint 21 are shown in FIGS. 14 to 16. FIG.

In the modified example of FIG. 14, the welded portions 25a and 25b are spaced apart in the circumferential direction without being overlapped on the inner circumference 23e side.

In the modified example of FIG. 15, the third line L3 overlaps the first line L1, and accordingly the other welded portion 25b extends radially.

In the modification of FIG. 16, welded portions 25a and 25b are formed in a curved shape.

In addition, the shape of the joint portion 21 can be appropriately set according to the difference in the amount of deformation between the inner and outer circumferences 23e and 23f of the wave washer 23, as described above. For example, welds 25a and 25b may be dashed by spacing adjacent weld spots 27 apart. Also, the opening angle and length of the welded portions 25a and 25b can be changed. Furthermore, it is also possible to change the shape of only one of the welded portions 25a and 25b. In addition, the joint portion 21 of Example 1 has a gap with respect to the inner circumference 23e and the outer circumference 23f of the wave washer 23 in plan view, but it is also possible to have a shape extending from the inner circumference 23e to the outer circumference 23f. is.

1 Flexible member 15 Base portion 17 Movable portion 19 Body portion 21 Joint portion 23 Wave washer 23a Peak portion 23b Valley portion 23e Inner circumference 23f Outer circumference 25a, 25b Welded portion L1 First line L2 Second line L3 Third line

Claims (4)

A main body portion in which a plurality of closed annular wave washers are laminated in the axial direction and adjacent portions are joined by a plurality of joint portions so as to be bendable in the axial direction by elastic deformation of the wave washers,
each of the plurality of joints includes a pair of linear welds,
One of the pair of welds is formed on a second line extending in a direction crossing a first line extending radially from the center of the wave washer, and the other weld is formed on the second line. formed on a third line extending in a direction intersecting with
Flexible member. The flexible member of claim 1, comprising:
The pair of welds are each formed in a continuous line,
Flexible member. The flexible member of claim 2, wherein
The pair of welded parts are V-shaped overlapping each other on the inner peripheral side of the wave washer,
Flexible member. The flexible member according to any one of claims 1 to 3,
Each of the plurality of wave washers has a plurality of ridges and troughs between the ridges in the circumferential direction, and the ridges and troughs of adjacent wave washers abut against each other. parts joined by said joints respectively,
Flexible member.

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