Patent ID: 12202134

DESCRIPTION OF EMBODIMENTS

The purpose of improving the followability of the driven part to the driving part was achieved by using double coils for the driving part and the movable part.

That is, the bending operation mechanism (1) includes a driving part (5), a driven part (7), and a linking part (9). The driving part (5) is elastically bendable, and the driven part (7) is provided apart from the driving part (5) and is elastically bendable. The linking part (9) connects between the driving part (5) and the driven part (7), and pulls and bends the driven part (7) according to the bending of the driving part (5).

Each of the driving part (5) and the driven part (7) includes an inner coil part (19) and an outer coil part (21) that are bendable in the axial direction, and corresponding wound parts (19a) of the inner coil part (19) are fitted in the pitches (21b) in adjacent wound parts (21a) of the outer coil part (21).

The length (L1) from the connection position of the linking part (9) with respect to the driving part (5) to the base end part (13) of the driving part (5) are allowable to be different from the length (L2) from the connection position of the linking part (9) with respect to the driven part (7) to the base end part (13) of the driven part (7).

In this case, the driving part (5) and the driven part (7) have different lengths in the axial direction, and the linking part (9) may connect the tip parts (11) of the driving part (5) and the driven part (7).

The linking part (9) is a cord-like member (25) that connects positions radially displaced from the center of the driving part (5) and the driven part (7). When θ1is the bending angle of the driving part (5), θ2is the bending angle of the driven part (7), r1is the amount of displacement of the cord-like member (25) at the driving part (5), and r2is the amount of displacement of the cord-like member (25) at the driven part (7), there is a relationship of θ1:θ2=r2:r1.

The linking part (9) includes one or more cord-like members (25), and each cord-like member (25) may connect the driving part (5) and the driven part (7) at positions different by 180 degrees in the circumferential direction.

Each cord-like member (25) is helically formed between the driving part (5) and the driven part (7) and the spiral shape between the driving part (5) and the driven part (7) causes the cord-like members (25) to be displaced by 180 degrees corresponding to the connection at the positions differing by 180 degrees.

Example 1

[Bending Operation Mechanism]

FIG.1is a perspective view showing a bending operation mechanism according to example 1 of the invention.FIG.2is an enlarged perspective view of a driving part of the bending operation mechanism.FIG.3is a perspective cross-sectional view of a part of the driving part. (A) and (B) ofFIG.4are cross-sectional views showing an inner cylinder used in the driving part, (A) ofFIG.4shows a normal state, and (B) ofFIG.4shows a bending state. (A) and (B) ofFIG.5are schematic cross-sectional views of the bending operation mechanism, (A) ofFIG.5shows a normal state, and (B) ofFIG.5shows a bending state.FIG.6is a perspective view showing the state of the drive wire of the bending operation mechanism.

The bending operation mechanism1is applied to joint function parts of various devices such as manipulators, robots, and actuators for medical and industrial purposes. A joint function part is an apparatus, a mechanism, a device or the like, with the functions as a joint that bends and extends.

The bending operation mechanism1of this example includes a shaft3, a driving part5, a driven part7, a linking part9, a flexible tube10as a flexible member, and a push-pull cable12.

The shaft3has a hollow tubular shape formed by metal or the like, for example, a cylindrical shape. A driving part5and a driven part7are provided at both ends of the shaft3. The shaft3thus functions as a base on which the driving part5and the driven part7are provided. For the base of the driving part5and the driven part7, an appropriate member may be used instead of the shaft3according to the equipment to which the bending operation mechanism1is applied.

The driving part5is coaxially provided at one end of the shaft3and configured to be elastically bendable in the axial direction. The axial direction means a direction along the axial center of the bending operation mechanism1, and includes directions strictly parallel to the axial center as well as slightly inclined directions.

The driving part5is a part that is directly or indirectly operated by the operator, and performs a bending motion according to the operation. The driving part5of this example includes a base part11, a movable part13, an inner cylinder15, and an outer cylinder17.

The base part11is a columnar body, such as a circular columnar body, made of resin, metal or the like. The base part11is attached to one end of the shaft3and constitutes the base end part of the driving part5. Note that the base part11is not limited to a columnar body, and may be formed in an appropriate form according to the equipment to which the bending operation mechanism1is applied.

The movable part13is, like the base part11, a columnar body, such as a circular columnar body, made of resin, metal or the like. The movable part13constitutes the tip part of the driving part5. Note that the movable part13also has an appropriate form according to the equipment to which the bending operation mechanism1is applied, and is not limited to a columnar body.

The movable part13is supported by the base part11that is displaceable in the axial direction by the inner cylinder15and the outer cylinder17.

The inner cylinder15is arranged along the axial direction of the driving part5. The inner cylinder15is a double coil that is able to be elastically bent and restored in the axial direction, and includes an inner coil part19and an outer coil part21.

The inner coil part19and the outer coil part21are each made of metal, resin or the like, and are elastic coil springs that are bendable in the axial direction. The cross-sectional shape of the wires of the inner coil part19and the outer coil part21is circular. However, the cross-sectional shape is not limited to a circle, and may be a semicircle, an ellipse or the like.

The inner coil part19has a smaller center diameter than the outer coil part21and is screwed into the outer coil part21. The center diameters of the inner coil part19and the outer coil part21are constant from one end to the other end in the axial direction. However, the center diameter of the outer coil part21may also be changed in the axial direction.

The outer coil part21has pitches21b, which are a plurality of gaps separating between axially adjacent wound parts21a(adjacent wound parts21a) in the axial direction. Corresponding wound parts19aof the inner coil part19are fitted into the plurality of pitches21bfrom the inside. Due to this fitting, the wound parts19aof the inner coil part19contact both the adjacent wound parts21aof the outer coil part21.

On the other hand, the inner coil part19has pitches19bas a plurality of gaps separating between axially adjacent wound parts19a(between wound parts19a) in the axial direction. Corresponding wound parts21aof the outer coil part21are fitted into the plurality of pitches19bfrom the outside. Due to this fitting, the wound parts21aof the outer coil part21contact both the adjacent wound parts19aof the inner coil part19.

With such a configuration, the inner cylinder15is restricted from being compressed in the axial direction.

The outer cylinder17is a cylindrical body arranged concentrically with the inner cylinder15and covering the outer circumference of the inner cylinder15. The outer cylinder17of this example is constructed by laminating a plurality of wave washers23in the axial direction. Axially adjacent wave washers23are joined together. This outer cylinder17is bendable by elastic deformation of the wave washers23.

Each wave washer23is formed in a closed ring from metal, resin or the like. Between the wave washers23adjacent in the axial direction, the ridge23aof one wave washer23abuts against the trough23bof the other wave washer23, and the abutting ridges23aand troughs23bare joined by any suitable means such as welding or bonding.

A plurality of flat washers24having a smaller deformation amount than the wave washers23are attached to both ends of the outer cylinder17in the axial direction. The base part11and the movable part13are connected to both ends of the outer cylinder17via the flat washers24. This connection is made by suitable means such as welding. Note that the flat washer24may be omitted.

The outer cylinder17is provided with insertion holes23cand24acommunicating in the axial direction between the ridges23aand the troughs23bof each wave washer23and at the part of the flat washer24corresponding thereto. The insertion holes23cand24aof this example are provided at intervals of 90 degrees in the circumferential direction.

The drive wire25of the linking part9is axially inserted through the insertion holes23cand24a. Thereby, the outer cylinder17functions as a guide that holds the drive wire25at a predetermined position.

It should be noted that the outer cylinder17is not limited to the one in which the wave washers23are laminated, and may be configured by other flexible members. For example, the outer cylinder17may be composed of a bellows made of a tubular body having a corrugated cross section or a double coil similar to the inner cylinder15.

The driven part7is coaxially provided at the other end of the shaft3and is provided apart from the driving part5. The driven part7constitutes a joint function part of a device to which the bending operation mechanism1is applied, and is configured to be elastically bendable in the axial direction. The bending of the driven part7is performed by following the bending of the driving part5.

The driven part7of this example has the same structure as the driving part5and is composed of a base part11, a movable part13, an inner cylinder15and an outer cylinder17. Therefore, each part of the driven part7may be referred to by replacing the description of the driving part5with the driven part7.

Note that the driven part7is configured in the opposite direction to the driving part5. Therefore, the bending direction of the driven part7is opposite to the bending direction of the driving part5. The movable part13of the driven part7constitutes a tip part of the driven part7, and an end effector or the like is attached thereto according to the equipment to which the bending operation mechanism1is applied.

The linking part9connects between the driving part5and the driven part7and pulls and bends the driven part7according to the bending of the driving part5. The linking part9includes a plurality of mutually parallel drive wires25as one or more cord-like members. In this example, four drive wires25are provided.

Each drive wire25is a cord-like member made of metal or the like. The drive wire25has a degree of flexibility that does not hinder bending and restoration of the driving part5and the driven part7of the bending operation mechanism1.

The cross-sectional shape of the drive wire25may be circular like the insertion holes23cand24aof the outer cylinder17, or may be oval or rectangular. Further, the drive wire25may be a stranded wire, a NiTi (nickel titanium) single wire, a piano wire, an articulated rod, a chain, a cord, a thread, a rope or the like, as long as the drive wire25is a cord-like member.

The drive wire25is axially inserted through the shaft3, the driving part5, and the driven part7. In the driving part5and the driven part7, the drive wire25is inserted through the insertion holes23cand24aof the outer cylinder17and guided. Inside the shaft3, the drive wire25is guided by a guide member not shown. The guide member is a plate or the like fixed inside the shaft3, and may have an insertion hole, a slit, or the like through which the drive wire25is inserted.

According to this guide, the drive wire25extends axially at a position radially displaced from the centers of the driving part5, the driven part7, and the shaft3when the bending operation mechanism1is straight (extended).

Both ends of the drive wire25are connected to positions displaced in the radial direction from the center of the movable part13as the tip parts of the driving part5and the driven part7according to the guide of the drive wire25. Thus, the drive wire25as the linking part9is configured to connect the positions displaced in the radial direction from the centers of the driving part5and the driven part7.

In this example, the amount of displacement r1of the drive wire25at the driving part5is equal to the amount of displacement r2of the drive wire25at the driven part7. Although the drive wire25connects between the movable parts13of the driving part5and the driven part7under tension, the tension of the drive wire25may be appropriately set according to the characteristics or the like of the bending operation mechanism1.

Both ends of the drive wire25are positioned in connection holes13aprovided in the movable part13, and are prevented from coming off by being engaged with the movable part13by end processing or the like. Both ends of the drive wire25are thereby connected to the driving part and the driven part7.

Therefore, in the drive wire25of this example, the engagement positions with the movable parts13on both sides are the connection positions of the linking part9with the driving part5and the driven part7. The connection positions are axial positions corresponding to each other, and are symmetrical with respect to a radial line passing through the center of the bending operation mechanism1in the axial direction in this example. The connection may be made by an appropriate technique such as welding or adhesion, and the connection position may be set according to the connection technique.

The length L1from the connection position of the linking part9to the driving part5to the base part11as the base end part of the driving part5is the same as the length L2from the connection position of the linking part9to the driven part7to the base part11as the base end part of the driven part7.

The length L1is the length from the connection position of the linking part9to the driving part5to an arbitrary axial position of the base part11of the driving part5. Similarly, the length L2is the length from the connection position of the linking part9to the driven part7to an arbitrary axial position of the base part11of the driven part7. The arbitrary axial positions of the base part11are axial positions corresponding to each other, and in this example, mean symmetrical positions with respect to a line passing through the axial center of the bending operation mechanism1along the radial direction.

Since the amounts of displacement r1and r2are equal as described above, in this example, the bending angle θ1when the driving part5is bent is equal to the bending angle θ2of the driven part7bent following the driving part5. The relationship between the length bending angles θ1and02and the amounts of displacement r1and r2is θ1:θ2=r2:r1. In addition, the bending angle refers to the central angle of the axial center of the inner cylinder15and the outer cylinder17which are responsible for the bending motion.

The flexible tube10is positioned at the axial center part of the bending operation mechanism1and is a cylindrical member made of resin or the like. Both ends of the flexible tube10are inserted through the inner cylinders15of the driving part5and the driven part7. This flexible tube10has a degree of flexibility that does not hinder the bending and restoration of the driving part5and the driven part7.

The push-pull cable12is inserted through the flexible tube10. The push-pull cable12operates an end effector or the like by advancing and retreating.

Depending on the device, it is possible to use a drive member such as an air tube other than the push-pull cable12, or another member having flexibility. Also, depending on the device, either one or both of the flexible members of the flexible tube10and the push-pull cable12may be omitted.

[Motion]

In the bending operation mechanism1of this example shown in (A) ofFIG.4and (A) ofFIG.5, when in a straight (extended) state where the driving part5and the driven part7are not bent, the corresponding wound parts19aof the inner coil part19are fitted between adjacent wound parts21aof the outer coil part21of the inner cylinder15in the driving part5and the driven part7.

Therefore, in the bending operation mechanism1, the inner and outer coil parts19and21of the inner cylinder15are not compressed even if a compressive force in the axial direction acts on the driving part5or the driven part7. As a result, the driving part5and the driven part7are not pushed in, and the length of the central part is able to be maintained.

Therefore, before the operator bends the driving part5, the driving part5and the driven part7are prevented from being pushed inadvertently, and the lengths of the central parts of the driving part5and the driven part7are prevented from fluctuating.

In this bending operation mechanism1, when bending the driven part7, the operator bends the driving part5in any direction in all directions of 360 degrees. As a result, any one or a plurality of drive wires25are pulled, and the driven part7is pulled and driven to be bent. Therefore, the end effector or the like of the equipment to which the bending operation mechanism1is applied is able to be oriented in a desired direction.

When the drive wire25is pulled, as shown in (B) ofFIG.4and (B) ofFIG.5, the pitches21bbetween the adjacent wound parts21aof the outer coil part21of the inner cylinder15becomes smaller on the inner side of the bend, and the pitches21bbetween the adjacent wound parts21aof the outer coil part21of the inner cylinder15on the outer side of the bend increases. As a result, the length of the central part of the inner cylinder15does not change even when bent, and the posture is stabilized.

At this time, the inner coil part19of the inner cylinder15is pushed out toward the outside of the bend. This extrusion of the inner coil part19is permitted by the increased pitches21bbetween adjacent wound parts21aof the outer coil part21of the inner cylinder15at the bent outer part. Therefore, the bending motion is able to be performed smoothly.

Moreover, during bending, the corresponding wound parts19aof the inner coil part19continue to fit between the adjacent wound parts21aof the outer coil part21of the inner cylinder15.

Therefore, as in the straight state, the driving part5and the driven part7are prevented from being pushed inadvertently due to compression in the axial direction, and fluctuations in the length of the central part is able to be suppressed. Therefore, the driven part7linearly follows the bending of the driving part5and bends with good followability.

Effect of Example 1

As described above, this example includes the elastically bendable driving part5, the elastically bendable driven part7provided apart from the driving part5, and the linking part9that connects the driving part5and the driven part7and pulls and bends the driven part7according to bending of the driving part5.

Each of the driving part5and the driven part7includes an inner coil part19and an outer coil part21that are bendable in the axial direction and the corresponding wound parts19aof the inner coil part19are fitted into the pitches21bbetween the adjacent wound parts21aof the outer coil part21.

Therefore, in this example, pushing of the driving part5and the driven part7in the axial direction is suppressed during bending and during non-bending before and after bending, and the followability of the driven part7to the driving part5is able to be improved, and enables intuitive operation.

Further, the linking part9is a drive wire25as a cord-like member that connects positions radially displaced from the center of the driving part5and the driven part7, and when the bending operation mechanism1sets so that the bending angle of the driving part5is θ1, θ2is the bending angle of the driven part7, r1is the amount of displacement of the drive wire25at the driving part and r2is the amount of displacement of the drive wire25at the driven part7, there is a relationship of θ1:θ2=r2:r1.

In this example, since pushing of the driving part5and the driven part7in the axial direction is suppressed, the relationship between the lengths L1and L2of the driving part5and the driven part7is maintained, and the θ1:θ2=r2:r1relationship is able to be reliably obtained. Therefore, the bending angles θ1and θ2of the driving part5and the driven part7is able to be set accurately according to the amount of displacement of the drive wire25.

In this example, the amounts of displacement r1and r2are set equal, and the bending angles θ1and θ2are set equal so the driven part7is able to be reliably bent by the amount of bending of the driving part5, and a more intuitive operation becomes possible.

Example 2

(A) and (B) ofFIG.7are schematic cross-sectional views of a bending operation mechanism according to example 2 of the invention, with (A) ofFIG.7showing a normal state and (B) ofFIG.7showing a bending state.FIG.8is a perspective view showing the state of the drive wire of the bending operation mechanism ofFIG.7. In addition, in Example 2, the same code is attached to the structure corresponding to example 1, and the repeated description is omitted.

In Example 2, the drive wires25as the respective cord-like members connect the driving part and the driven part7at positions different by 180 degrees in the circumferential direction. Others are the same as example 1.

That is, each drive wire25is provided so as to be gradually displaced in the circumferential direction so as to form a spiral shape, and is displaced from the connection position to the movable part13of the driving part5and the connection position to the movable part13of the driven part7by 180 degrees in the circumferential direction. The amount of displacement of the drive wire25is not limited to 180 degrees, but may be any other angle, and the driving part5and the driven part7may be connected at different positions in the circumferential direction according to this angle.

The drive wire25of this example is formed in a spiral shape within the shaft3that includes the driving part5and the driven part7, and due to the spiral shape in the shaft3, the drive wire25is displaced 180 degrees in the circumferential direction corresponding to the connection at positions different by 180 degrees. In other words, the drive wire25is not spiral but parallel in the driving part5and the driven part7. However, the drive wire25may be configured in a spiral shape as a whole from the movable part13of the driving part5to the movable part13of the driven part7.

In the shaft3, a plurality of holding members or the like arranged in the axial direction are formed with holding holes that are gradually displaced in the circumferential direction, and the drive wire25is inserted through the holding hole to hold the spiral shape. The drive wire25is inserted through the driving part5and the driven part7in the same manner as in the example 1.

In example 2, the driven part7is able to be bent in the direction in which the driving part5is bent, and a more intuitive operation is able to be performed. Further, in this example, since the drive wire25is spiral only within the shaft3, the structures of the driving part5and the driven part7are prevented from being complicated, the operation is stabilized, and versatility is improved. In addition, even in the example 2, the same effects as in the example 1 are able to be obtained.

Example 3

FIG.9is a schematic cross-sectional view showing a bending operation mechanism according to Example 3 of the present invention when bent. In addition, in Example 3, the same code is attached to the structure corresponding to Example 1, and the repeated description is omitted.

In the example 3, the length L1from the connection position of the linking part9to the driving part5to the base part11as the base end part of the driving part5is longer than the length L2from the connection position of the linking part9to the driven part7to the base part11as the base end part of the driven part7. Others are the same as example 1.

In this example, the length of the driving part5is longer than the length of the driven part7in the axial direction, and the drive wire25of the linking part9is connected to the movable parts13of the driving part5and the driven part7as in example 1.

Note that the length L1may be formed shorter than the length L2. In this case, the length of the driving part5is made shorter in the axial direction than the length of the driven part7, and the drive wire25of the linking part9connects between the movable parts13of the driving part5and the driven part7as in example 1. Therefore, in this example, the length L1may be different from the length L2.

In example 3, as in example 1, the bending angle θ1of the driving part5and the bending angle θ2of the driven part7are equal so the amount of displacement of the movable part13of the driving part5to reach the bending angle θ1is larger than the amount of displacement of the movable part13of the driven part7to reach the bending angle θ2.

As a result, a small displacement of the movable part13of the driven part7is able to be controlled by a large displacement of the movable part13of the driving part5. The delicate movement of the driven part7is made possible without reducing the size of the driving part5, the operability of the delicate movement is able to be improved, and operation errors are able to be suppressed.

Conversely, if the length L1is shorter than the length L2, a small displacement of the movable part13of the driving part5is able to control a large displacement of the movable part13of the driven part7, and the driven part7can be caused to make a large displacement without increasing the size of the driving part5.

In addition, this example is also able to achieve the same effects as example 2.

Example 4

FIG.10is a schematic cross-sectional view showing a bending operation mechanism according to example 4 of the invention when bent. In addition, in example 4, the same code is attached to the structure corresponding to example 2, and the repeated description is omitted.

In the example 4, the amount of displacement r1of the drive wire25in the driving part5is made larger than the amount of displacement r2of the drive wire25in the driven part7. Others are the same as the example 1.

That is, the outer cylinder17of the driving part5has a larger diameter than the outer cylinder17of the driven part7, and accordingly the insertion hole23cof the driving part5is arranged radially outside the insertion hole23cof the driven part7. By inserting the drive wire25through the insertion hole23c, the amount of displacement r1is made larger than the amount of displacement r2.

Therefore, the bending angle θ1of the driving part5is smaller than the bending angle θ2of the driven part7from the relationship of θ1:θ2=r2:r1. Note that the amount of displacement r1may be smaller than the amount of displacement r2.

In the example 4, it is possible to cause the driven part7to perform a bending operation with a large bending angle θ2by the bending operation with a small bending angle θ1of the driving part5. Therefore, in this example, the driven part7is able to be greatly bent with a small operating force. Moreover, the diameter of the driving part5is able to be increased to facilitate operation, and bending is able to be performed with a smaller operating force.

Conversely, when the amount of displacement r1is smaller than the amount of displacement r2, the bending operation with the large bending angle θ1of the driving part5is able to cause the driven part7to perform the bending operation with the small bending angle θ2. Therefore, it is possible to perform delicate movements of the driven part7, improve the operability of the delicate movements, and suppress operational errors.

In addition, even in the example 4, the same effect as the example 2 are able to be obtained.

Example 5

FIG.11is a schematic view showing the state of the drive wire of the bending operation mechanism according to example 5 of the invention. In addition, in example 4, the same code is attached to the structure corresponding to example 1, and the repeated description is omitted. In this example, three drive wires25are used. Others are the same as the example 1. The three drive wires25are arranged at predetermined intervals in the circumferential direction, and connect the driving part5and the driven part7at positions facing each other in the axial direction.

Even in the example 5, the same effects as in the example 1 are able to be obtained.

FIG.12is a schematic view showing a state of a drive wire of a bending operation mechanism according to a modification of the example 5.FIG.13is a conceptual view showing connection positions of drive wires of the bending operation mechanism ofFIG.12.

As a modification, in example 5, being the same as example 2, the drive wire25connects the driving part5and the driven part7at positions different by 180 degrees in the circumferential direction.

This modified example is able to achieve the same effects as the example 2.