JP6948694B2 - Variable surface shape structure - Google Patents

Description

The present disclosure relates to a variable surface shape structure in which the shape of the surface changes.

There are cases where you want to change the frictional characteristics of the surface of a robot hand, transport belt, building floor, etc., depending on the application and environment. Regarding friction control, the development of materials whose surface condition changes by receiving an external force is underway.

Non-Patent Document 1 discloses a composite material in which a woven fabric is embedded in the surface of rubber as a base material. In this composite material, when the rubber of the base material is compressed, the structural change of the cloth fiber overlaps with the wrinkle structure generated on the surface, and the frictional force on the surface changes.

Kousuke Suzuki, Yuji Hirai and Takaya Ohzono, "Oscillating Friction on Shape-Tunable Wrinkles", Applied Materials and Interfaces, 20 years 6, No. 13, p. 10121-10131

The composite material according to Non-Patent Document 1 needs to use a flexible material that expands and contracts as a base material, is easily worn, and is easily affected by the environmental temperature, so that its use may be limited. Further, since general mechanical parts are required to have dimensional accuracy in assembly and the like, deformation of the base material is difficult to tolerate. The present inventors have come to think that there is room for improvement in terms of versatility of the variable surface shape structure used for friction control.

The present disclosure has been made in view of such circumstances, and one of the purposes thereof is to provide a highly versatile surface shape variable structure.

In order to solve the above problems, the surface shape variable structure of a certain aspect of the present disclosure includes an internal space formed in the member and a surface portion covering at least a part of the internal space. The surface portion receives a force from the internal space side and changes from a convex shape to a concave shape or from a concave shape to a convex shape with respect to the internal space, and the surface portion is in a convex shape from the surface of the member. It is provided at a position where it does not protrude, and the surface side of the member comes into contact with another member via a fluid.
Another aspect of the present disclosure is also a variable surface shape structure. This structure includes an internal space formed in the member and a surface portion that covers at least a part of the internal space. The surface portion includes a central portion and an annular portion in which the inner peripheral edge is connected to the outer peripheral edge of the central portion, and the pressure from the internal space side increases in a state where both the central portion and the annular portion have a concave shape. And, while maintaining the concave shape of the central part, the annular part changes from the concave shape to the convex shape, the central part is concave, and the annular part is convex, and the internal space side. When the pressure from is increased, the annular portion maintains the convex shape while the central portion changes from the concave shape to the convex shape.

According to the present disclosure, it is possible to provide a highly versatile surface shape variable structure.

It is a perspective view of the member provided with the surface shape variable structure which concerns on 1st Embodiment. It is a top view of the member provided with the surface shape variable structure which concerns on 1st Embodiment. 3 (a) to 3 (b) are cross-sectional views taken along the line AA of FIG. 2 and show how the shape of the surface portion changes. It is a figure which shows the result of having measured the height of the surface part which concerns on 1st Embodiment. It is a figure which shows the result of having measured the friction coefficient of the member provided with the surface shape variable structure which concerns on 1st Embodiment. 6 (a) to 6 (b) are cross-sectional views of a member having a surface shape variable structure according to a second embodiment, and are views showing how the shape of the surface portion changes. 7 (a) to 7 (b) are cross-sectional views of the member provided with the surface shape variable structure according to the third embodiment, and are views showing how the shape of the surface portion changes. It is a top view of the member provided with the surface shape variable structure which concerns on 4th Embodiment. 9 (a) to 9 (c) are cross-sectional views of the member of FIG. 8 and show how the shape of the surface portion changes. It is a top view which shows the modification of the surface shape variable structure. It is the schematic of the BB cross section of FIG.

In the following embodiments, the same components are designated by the same reference numerals, and duplicate description will be omitted. Further, in each drawing, for convenience of explanation, some of the components are omitted as appropriate.

[First Embodiment]
Before concretely explaining the variable surface shape structure according to the first embodiment, an outline will be described. The surface shape variable structure according to the first embodiment includes an internal space formed in the member and a surface portion covering at least a part of the internal space, and is formed in the vicinity of the surface of the member. The surface portion receives a changing pressure in the internal space and changes into a convex shape or a concave shape with respect to the internal space. The pressure in the interior space is controlled, for example, by a pump. When the pressure in the internal space exceeds a predetermined value, the surface portion changes from a concave shape to a convex shape and protrudes from the member, and the friction coefficient of the member surface increases. Further, when the pressure in the internal space falls below a predetermined value, the surface portion changes from a convex shape to a concave shape and becomes a recessed state from the member, and the friction coefficient of the member surface decreases. With such a structure, the frictional characteristics of the member surface can be controlled by changing the shape of the surface portion according to the pressure in the internal space.

FIG. 1 is a perspective view of a member 12 having a surface shape variable structure 10 according to the first embodiment, and FIG. 2 is a plan view thereof. 3A and 3B are cross-sectional views taken along the line AA of FIG. 2, showing how the shape of the surface portion 22 of the variable surface shape structure 10 changes. As shown in each figure, a Cartesian coordinate system including an x-axis, a y-axis, and a z-axis is defined. The x-axis and y-axis are orthogonal to each other within the bottom surface of the member 12. The z-axis extends in a direction perpendicular to the x-axis and the y-axis. The positive directions of the x-axis, y-axis, and z-axis are defined in the directions of the arrows in each figure, and the negative directions are defined in the directions opposite to the arrows. In the following description, the direction parallel to the x-axis may be referred to as "left-right direction", the positive direction side of the x-axis may be referred to as "right side", and the negative direction side of the x-axis may be referred to as "left side". The direction parallel to the y-axis may be referred to as the "front-back direction", the positive direction side of the y-axis may be referred to as the "front side", and the negative direction side of the y-axis may be referred to as the "rear side". Further, the direction parallel to the z-axis may be referred to as "vertical direction", the positive direction side of the z-axis may be referred to as "upper side", and the negative direction side of the z-axis may be referred to as "lower side".

The member 12 is formed of a resin material in a rectangular parallelepiped shape, and is provided with a total of nine surface shape variable structures 10 arranged in three rows in a direction parallel to the x-axis and a direction parallel to the y-axis. The resin material forming the member 12 preferably has a tensile strength of 40 to 55 MPa, a tensile elastic modulus of 1800 to 2100 MPa, and a fracture elongation rate of 5 to 35% in accordance with JIS K7161. Further, it is preferable that the bending strength according to JIS K7171 is 60 to 80 MPa and the flexural modulus is 1900 to 2400 MPa. Further, the compressive strength according to JIS K7181 is preferably 70 to 80 MPa. The density of the resin material forming the member 12 was 1111 kg / m ³ at 23 ° C. The member 12 has a width in the left-right direction and a depth in the front-rear direction of 36 mm, and a height in the up-down direction of 16 mm.

As shown in FIG. 3, the surface shape variable structure 10 includes a recessed portion 20 forming an internal space 24 and a surface portion 22. The recessed portion 20 is formed so as to be recessed in a columnar shape from the upper surface of the member 12 downward. The surface portion 22 is formed in a curved shape in a cross section parallel to the z-axis and in a circular shape having the same diameter as the recessed portion 20 in a plan view. Further, the surface portion 22 is integrally formed with the same resin material as the member 12 at the open end of the recessed portion 20, and covers and seals the recessed portion 20. The diameter of the recess 20 and the surface 22 in a plan view is 6 mm, and the distance between the variable surface shape structure 10 in the left-right direction and the front-rear direction is 3 mm. The thickness of the surface portion 22 is 0.2 mm, and the radius of curvature passing through the center is 25 mm.

An internal space 24 is formed between the recess 20 and the surface 22. A connecting hole 16 for connecting the internal space 24 is formed between the recessed portions 20 adjacent to each other in the member 12. Further, a connecting hole 16 extends from the recessed portion 20 in the center of the right column toward the right side, and a connecting port 14 connected to a pump (not shown) is formed on the side surface of the member 12. With such a configuration, the pump can be connected to the connection port 14 and the pressure in each internal space 24 can be adjusted at the same time.

When the pressure in the internal space 24 is reduced by the pump connected to the connection port 14, a downward force acts on the surface portion 22, and as shown in FIG. 3A, the surface portion 22 has a concave shape with respect to the internal space 24. Become. Further, when the pressure in the internal space 24 is increased, an upward force acts on the surface portion 22, and the surface portion 22 has a convex shape with respect to the internal space 24 as shown in FIG. 3 (b). In this way, the surface portion 22 changes into a concave shape or a convex shape with a predetermined pressure value in the internal space 24 as a boundary. When the pressure in the internal space 24 changes from less than a predetermined value to a predetermined value or more, the surface portion 22 changes from a concave shape to a convex shape. Further, when the pressure in the internal space 24 changes from a state of being equal to or higher than a predetermined value to less than a predetermined value, the surface portion 22 changes from a convex shape to a concave shape.

FIG. 4 is a diagram showing the result of measuring the height of the surface portion 22 according to the first embodiment. In the graph of FIG. 4, the horizontal axis shows the position in the left-right direction, and the vertical axis shows the height of the surface portion 22 in which the upper surface position of the member 12 is zero in the vertical direction. The surface portion 22 projects about 300 μm from the upper surface of the member 12 in a convex shape. In this state, since the surface portion 22 protrudes from the upper surface of the member 12, the friction coefficient of the upper surface of the member 12 is higher than that in the concave state. Further, the surface portion 22 is recessed by about 300 μm from the upper surface of the member 12 in a concave shape. In this state, since the surface portion 22 is recessed from the upper surface of the member 12, the friction coefficient of the upper surface of the member 12 is lower than that in the convex state.

FIG. 5 is a diagram showing the results of measuring the friction coefficient of the member 12 including the surface shape variable structure 10 according to the first embodiment. Using a block-on-disk friction tester, the upper surface of the member 12 was pressed against the glass plate with a constant load, and the friction coefficient when the glass plate was rotated was measured. In the graph of FIG. 5, the horizontal axis represents the measurement time and the vertical axis represents the friction coefficient μ. About 70 seconds after the start of measurement, the pressure in the internal space 24 was changed to change the surface portion 22 from a convex shape to a concave shape. The average value of the friction coefficient μ when the surface portion 22 had a convex shape was 0.55. Further, the average value of the friction coefficient μ in the state where the surface portion 22 was concave was 0.33. From this result, it can be seen that the surface portion 22 can be changed into a convex shape or a concave shape by the pressure of the internal space 24, and the friction coefficient on the upper surface of the member 12 can be controlled.

The surface shape variable structure 10 according to the first embodiment has been described above. In the surface shape variable structure 10, the surface portion 22 changes into a convex shape or a concave shape according to the pressure in the internal space 24. Thereby, the friction coefficient of the surface of the member 12 can be controlled. The member 12 including the variable surface shape structure 10 can be formed by using a metal material or the like in addition to the resin material, and has a higher degree of freedom in material selection as compared with the prior art. Further, since the shape of the member 12 does not change, it can be incorporated into various mechanical parts and the like.

For example, the surface shape variable structure 10 may be provided on the gripping surface of the robot hand. When holding a slippery object, the surface portion 22 is formed into a convex shape to increase the friction coefficient of the gripping surface. This makes it difficult to drop the object. If you have a non-slip object, make the surface 22 concave to reduce the coefficient of friction. As a result, wear of the surface portion 22 can be suppressed.

The surface shape variable structure 10 may be provided on the transport surface of the transport belt. When a slippery object is placed, the surface portion 22 is formed into a convex shape to increase the coefficient of friction. This makes it difficult for the object to slip off the transport belt. When a non-slip object is placed, the surface portion 22 is made concave to reduce the coefficient of friction. As a result, wear of the surface portion 22 can be suppressed.

The surface shape variable structure 10 may be provided on the surface of the floor material or the sole. In this case, the friction coefficient of the surface is optimized according to the temperature, humidity, and weather, so that it is not slippery and easy to walk regardless of the environment.

The surface shape variable structure 10 may be provided on the surface of the component or the surface of the spacer inserted between the components. In this case, the surface portion 22 can be changed into a convex shape or a concave shape according to the gap between the parts, and the dimensional tolerance of the parts can be absorbed.

The surface shape variable structure 10 may be provided on the surface of the door stopper. In this case, for example, the shape of the surface portion 22 is changed by a switch. This makes it possible to easily perform operations such as restricting the opening and closing of the door and opening the door.

The surface shape variable structure 10 may be provided on the surface of a fall prevention member such as furniture. In this case, a fall prevention member is inserted between the top surface and the ceiling of the installed furniture, and the shape of the surface portion 22 is changed according to the interval. As a result, furniture and the like can be easily prevented from tipping over.

The surface shape variable structure 10 may be provided on the inner peripheral surface of the bearing that supports the shaft. In this case, depending on the usage situation, the surface portion 22 can be formed into a convex shape to brake the rotation of the shaft, or the surface portion 22 can be formed into a concave shape to reduce the frictional force with the shaft.

The surface shape variable structure 10 may be provided on the inner peripheral surface of the pipe or the flow path through which the fluid flows. In this case, the flow rate can be controlled by changing the shape of the surface portion 22.

The surface shape variable structure 10 may be provided on the surface of the actuator. In this case, when the surface portion 22 has a convex shape, other parts can be pushed and moved with high accuracy by a minute distance.

In the member 12 according to the first embodiment, the internal space 24 of the surface shape variable structure 10 is connected by the connecting hole 16, but the present invention is not limited to this. Different pumps may be connected to each or a plurality of structural groups of the variable surface shape structure 10 to individually change the pressure in the internal space. As a result, the shape of the surface portion 22 can be changed depending on the location, and the friction coefficient of the surface of the member 12 can be locally controlled.

In the surface shape variable structure 10 according to the first embodiment, the pressure in the internal space 24 is adjusted by using a pump, but the pressure is not limited to this. For example, the pump may circulate a liquid such as water or oil to adjust the pressure in the internal space 24. In this case as well, the friction coefficient of the surface of the member 12 can be controlled by changing the shape of the surface portion 22.

In the surface shape variable structure 10 according to the first embodiment, the surface portion 22 is integrally formed of the same material as the member 12, but the present invention is not limited to this. For example, the surface portion 22 may be formed of a material different from that of the member 12 and joined to the open end of the recessed portion 20. In this case as well, the coefficient of friction on the surface of the member 12 can be controlled in the same manner. The material of the member 12 and the surface portion 22 is not limited to the resin material, and may be a metal material. When a metal material is used, wear resistance is improved.

In the surface shape variable structure 10 according to the first embodiment, the surface portion 22 has a curved shape, but the present invention is not limited to this. The surface portion 22 may be polygonal in a plan view, convex or concave, and may be a cone or a polyhedron.

[Second Embodiment]
6 (a) and 6 (b) are cross-sectional views of the member 12 including the surface shape variable structure 30 according to the second embodiment, and are views showing how the shape of the surface portion 32 changes. The surface shape variable structure 30 according to the second embodiment is provided in a position where the surface portion 32 does not protrude from the opening of the recessed portion 20 and the surface of the member 12 in a convex shape. It is different from the form of.

When the upper surface side of the member 12 comes into contact with another member via an oil film formed by the lubricating oil, when the pressure in the internal space 24 is adjusted to change the surface portion 32 into a convex or concave shape, an oil film between the members is formed. Thickness changes. When the surface portion 32 has a convex shape, the lubricating oil is pushed out from the recessed portion 20, so that the oil film between the members becomes thicker than when the surface portion 32 has a concave shape. When the surface portion 32 has a concave shape, the lubricating oil enters the recessed portion 20, so that the oil film between the members becomes thinner than when the surface portion 32 has a convex shape. Thereby, the oil film thickness can be adjusted to control the contact state between the members.

The second embodiment has been described above. The surface shape variable structure 30 according to the second embodiment may be provided on the inner peripheral surface of the pipe or the flow path through which the fluid flows, as in the first embodiment. In this case, the flow rate of the fluid flowing through the pipe or the like can be controlled by changing the shape of the surface portion 32.

Further, the surface shape variable structure 30 may be provided on the suction surface of the suction pad. In this case, if the surface portion 32 is changed from a convex shape to a concave shape while the suction surface is pressed against the object, the surface portion 32 is attracted to the object due to the negative pressure generated in the recessed portion 20. By utilizing the negative pressure generated in each surface shape variable structure 30, the entire surface can be adsorbed under a uniform load, and it is less likely to be damaged when holding a thin work such as a silicon wafer.

[Third Embodiment]
7 (a) and 7 (b) are cross-sectional views of the member 12 including the surface shape variable structure 40 according to the third embodiment, and are views showing how the surface portion 42 is deformed. The surface shape variable structure 40 according to the third embodiment is different from the first and second embodiments in that the surface shape variable structure 40 includes an actuator 46 provided in the internal space 24 and pushes and pulls the surface portion 42 in the vertical direction. do.

The actuator 46 includes an arm 48 provided at the bottom of the recess 20 and having an upper end connected to the lower side surface of the surface 42. The actuator 46 is controlled by a control device (not shown) to move the arm 48 in the vertical direction to change the surface portion 42 into a convex shape or a concave shape. When the actuator 46 pushes up the arm 48 upward, the surface portion 42 becomes convex. Further, when the arm 48 is pulled downward, the surface portion 42 becomes concave.

The third embodiment has been described above. By using the actuator 46, the response speed of the shape change of the surface portion 42 is improved as compared with the case where the pressure of the internal space 24 is changed by the pump.

[Fourth Embodiment]
FIG. 8 is a plan view of the member 12 including the surface shape variable structure 50 according to the fourth embodiment. 9 (a) to 9 (c) are cross-sectional views of the member 12 of FIG. 8 and show how the surface portion 52 is deformed. The surface shape variable structure 50 according to the fourth embodiment is different from the first to third embodiments in that the surface portion 52 includes a central portion 54 and an annular portion 56.

The central portion 54 and the annular portion 56 are integrally formed of the same resin material as the member 12, and each has a curved shape in a cross section parallel to the z-axis. The central portion 54 is formed in a circular shape, and the outer peripheral edge is connected to the inner peripheral edge of the annular portion 56. The annular portion 56 is formed in an annular shape, and the outer peripheral edge is connected to the open end of the recessed portion 20. The radius of curvature of the central portion 54 is smaller than the radius of curvature of the annular portion 56.

FIG. 9A shows a state in which both the central portion 54 and the annular portion 56 have a concave shape. When the pressure in the internal space 24 increases from this state, as shown in FIG. 9B, the annular portion 56 first changes to a convex shape with respect to the internal space 24. Since the annular portion 56 projects upward from the surface of the member 12, the friction coefficient of the surface of the member 12 becomes larger than that in the state of FIG. 9A. When the pressure in the internal space 24 is further increased, as shown in FIG. 9C, the central portion 54 changes to a convex shape with respect to the internal space 24. Since the central portion 54 protrudes upward from the annular portion 56, the friction coefficient on the surface of the member 12 is further increased as compared with the state shown in FIG. 9B. In this way, the surface portion 52 includes a central portion 54 and an annular portion 56 that are deformed by different pressures, and the friction coefficient of the surface of the member 12 can be controlled in three stages.

The fourth embodiment has been described above. If one or more annular portions are provided between the outer circumference of the annular portion 56 and the open end of the recessed portion 20, the friction coefficient can be controlled in four or more steps.

The present disclosure has been described above based on the examples. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components and combinations of each processing process, and that such modifications are also within the scope of the present disclosure. .. For example, as shown in FIG. 10, a pillar body 62 may be provided between the surface shape variable structures 60, and the surface portion 64 may be supported by a plurality of pillar bodies 62. FIG. 11 is a schematic view of a cross section taken along the line BB of FIG. In this case, since the connecting holes connecting the variable surface shape structures 60 are enlarged and the pressure in the internal space 24 can be easily maintained uniformly, the simultaneous control of the plurality of variable surface shape structures 60 can be easily performed.

The outline of one aspect of the present disclosure is as follows. The surface shape variable structure of an aspect of the present disclosure includes an internal space formed in the member and a surface portion covering at least a part of the internal space. The surface portion receives a force from the internal space side and changes from a convex shape to a concave shape or from a concave shape to a convex shape with respect to the internal space.

According to this aspect, the surface portion changes to a convex shape or a concave shape by receiving a force from the internal space side. The member provided with the variable surface shape structure can be formed by using a metal material or the like in addition to the resin material, and has a high degree of freedom in material selection. Moreover, since the shape of the member itself does not change, it can be incorporated into various machine parts and is highly versatile.

The shape of the surface portion may change due to the changing pressure in the internal space. In this case, the shape of the surface portion can be controlled by changing the pressure in the internal space with a simple configuration.

An actuator provided in the internal space to push and pull the surface portion may be further provided. In this case, the response speed for deforming the surface portion can be increased.

The surface portion may protrude from the surface of the member in a convex shape. In this case, the coefficient of friction of the surface of the member provided with the variable surface shape structure can be controlled.

The surface portion may be provided at a position where it does not protrude from the surface of the member in a convex shape. In this case, in a configuration in which a member provided with a variable surface shape structure comes into contact with another member via a fluid such as lubricating oil, the thickness of the fluid between the members is adjusted and contacted by changing the shape of the surface portion. You can control the state.

The surface portion includes a central portion and an annular portion in which the inner peripheral edge is connected to the outer peripheral edge of the central portion, and the central portion and the annular portion independently change to a convex shape or a concave shape with respect to the internal space. good. In this case, since the shape of the surface portion changes in three steps, the friction coefficient of the surface and the thickness of the fluid between the members can be controlled in three steps or more.

10, 30, 40, 50, 60 Surface shape variable structure, 20 recesses, 22, 32, 42, 52, 64 surface parts, 46 actuators, 54 central parts, 56 annular parts.

Claims (2)

The internal space formed in the member and
A surface portion that covers at least a part of the internal space is provided.
The surface portion receives a force from the internal space side and changes from a convex shape to a concave shape or from a concave shape to a convex shape with respect to the internal space.
The surface portion is provided at a position where it does not protrude from the surface of the member in a convex shape.
A variable surface shape structure characterized in that the surface side of the member comes into contact with another member via a fluid. The internal space formed in the member and
A surface portion that covers at least a part of the internal space is provided.
The surface portion includes a central portion and an annular portion whose inner peripheral edge is connected to the outer peripheral edge of the central portion.
When the pressure from the internal space side increases in a state where both the central portion and the annular portion have a concave shape, the annular portion changes from a concave shape to a convex shape while maintaining the concave shape of the central portion. Changed to
When the pressure from the internal space side increases in a state where the central portion has a concave shape and the annular portion has a convex shape, the central portion changes from a concave shape to a convex shape while changing. A surface shape variable structure characterized in that the annular portion maintains a convex shape.

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